[svn-r27237] Description:

    Merge v3 metadata cache changes to trunk.  Yay! :-)

Tested on:
    MacOSX/64 10.10.3 (amazon) w/serial & parallel
    Linux/32 2.6.x (jam) w/serial & parallel
    (daily tested on branch)

80 files changed, 11390 insertions, 8004 deletions

diff --git a/src/H5AC.c b/src/H5AC.c
index db5a06f..c6b0b47 100644
--- a/src/H5AC.c
+++ b/src/H5AC.c
@@ -128,8 +128,7 @@ static herr_t H5AC__receive_haddr_list(MPI_Comm mpi_comm, int *num_entries_ptr,
     haddr_t **haddr_buf_ptr_ptr);
 static herr_t H5AC__receive_candidate_list(const H5AC_t *cache_ptr,
     int *num_entries_ptr, haddr_t **haddr_buf_ptr_ptr);
-static herr_t H5AC__receive_and_apply_clean_list(H5F_t *f, hid_t primary_dxpl_id,
-    hid_t secondary_dxpl_id);
+static herr_t H5AC__receive_and_apply_clean_list(H5F_t *f, hid_t dxpl_id);
 static herr_t H5AC__tidy_cache_0_lists(H5AC_t *cache_ptr, int num_candidates,
     haddr_t *candidates_list_ptr);
 static herr_t H5AC__rsp__dist_md_write__flush(H5F_t *f, hid_t dxpl_id);
@@ -201,6 +200,7 @@ static const char *H5AC_entry_type_names[H5AC_NTYPES] =
     "fixed array data block",
     "fixed array data block pages",
     "superblock",
+    "driver info",
     "test entry"	/* for testing only -- not used for actual files */
 };
 
@@ -575,7 +575,7 @@ H5AC_dest(H5F_t *f, hid_t dxpl_id)
 #endif /* H5_HAVE_PARALLEL */
 
     /* Destroy the cache */
-    if(H5C_dest(f, dxpl_id, H5AC_dxpl_id) < 0)
+    if(H5C_dest(f, dxpl_id) < 0)
         HGOTO_ERROR(H5E_CACHE, H5E_CANTFREE, FAIL, "can't destroy cache")
     f->shared->cache = NULL;
 
@@ -628,8 +628,7 @@ H5AC_expunge_entry(H5F_t *f, hid_t dxpl_id, const H5AC_class_t *type,
     HDassert(f->shared);
     HDassert(f->shared->cache);
     HDassert(type);
-    HDassert(type->clear);
-    HDassert(type->dest);
+    HDassert(type->serialize);
     HDassert(H5F_addr_defined(addr));
 
 #if H5AC__TRACE_FILE_ENABLED
@@ -645,7 +644,7 @@ H5AC_expunge_entry(H5F_t *f, hid_t dxpl_id, const H5AC_class_t *type,
 }
 #endif /* H5AC__TRACE_FILE_ENABLED */
 
-    if(H5C_expunge_entry(f, dxpl_id, H5AC_dxpl_id, type, addr, flags) < 0)
+    if(H5C_expunge_entry(f, dxpl_id, type, addr, flags) < 0)
         HGOTO_ERROR(H5E_CACHE, H5E_CANTEXPUNGE, FAIL, "H5C_expunge_entry() failed.")
 
 done:
@@ -710,7 +709,7 @@ H5AC_flush(H5F_t *f, hid_t dxpl_id)
 
     /* Flush the cache */
     /* (Again, in parallel - writes out the superblock) */
-    if(H5C_flush_cache(f, dxpl_id, H5AC_dxpl_id, H5AC__NO_FLAGS_SET) < 0)
+    if(H5C_flush_cache(f, dxpl_id, H5AC__NO_FLAGS_SET) < 0)
         HGOTO_ERROR(H5E_CACHE, H5E_CANTFLUSH, FAIL, "Can't flush cache.")
 
 done:
@@ -818,8 +817,7 @@ H5AC_insert_entry(H5F_t *f, hid_t dxpl_id, const H5AC_class_t *type, haddr_t add
     HDassert(f->shared);
     HDassert(f->shared->cache);
     HDassert(type);
-    HDassert(type->flush);
-    HDassert(type->size);
+    HDassert(type->serialize);
     HDassert(H5F_addr_defined(addr));
     HDassert(thing);
 
@@ -841,7 +839,7 @@ H5AC_insert_entry(H5F_t *f, hid_t dxpl_id, const H5AC_class_t *type, haddr_t add
 #endif /* H5AC__TRACE_FILE_ENABLED */
 
     /* Insert entry into metadata cache */
-    if(H5C_insert_entry(f, dxpl_id, H5AC_dxpl_id, type, addr, thing, flags) < 0)
+    if(H5C_insert_entry(f, dxpl_id, type, addr, thing, flags) < 0)
         HGOTO_ERROR(H5E_CACHE, H5E_CANTINS, FAIL, "H5C_insert_entry() failed")
 
 #if H5AC__TRACE_FILE_ENABLED
@@ -1138,9 +1136,8 @@ done:
  */
 void *
 H5AC_protect(H5F_t *f, hid_t dxpl_id, const H5AC_class_t *type, haddr_t addr,
-    void *udata, H5AC_protect_t rw)
+    void *udata, unsigned flags)
 {
-    unsigned		protect_flags = H5C__NO_FLAGS_SET;
     void *		thing;          /* Pointer to native data structure for entry */
 #if H5AC__TRACE_FILE_ENABLED
     char                trace[128] = "";
@@ -1156,47 +1153,36 @@ H5AC_protect(H5F_t *f, hid_t dxpl_id, const H5AC_class_t *type, haddr_t addr,
     HDassert(f->shared);
     HDassert(f->shared->cache);
     HDassert(type);
-    HDassert(type->flush);
-    HDassert(type->load);
+    HDassert(type->serialize);
     HDassert(H5F_addr_defined(addr));
 
+    /* Check for unexpected flags -- H5C__FLUSH_COLLECTIVELY_FLAG
+     * only permitted in the parallel case.
+     */
+#ifdef H5_HAVE_PARALLEL
+    HDassert(0 == (flags & (unsigned)(~(H5C__READ_ONLY_FLAG | \
+                                        H5C__FLUSH_LAST_FLAG | \
+                                        H5C__FLUSH_COLLECTIVELY_FLAG))));
+#else /* H5_HAVE_PARALLEL */
+    HDassert(0 == (flags & (unsigned)(~(H5C__READ_ONLY_FLAG | \
+                                        H5C__FLUSH_LAST_FLAG))));
+#endif /* H5_HAVE_PARALLEL */
+
     /* Check for invalid access request */
-    if(0 == (H5F_INTENT(f) & H5F_ACC_RDWR) && rw == H5AC_WRITE)
+    if((0 == (H5F_INTENT(f) & H5F_ACC_RDWR)) &&  (0 == (flags & H5C__READ_ONLY_FLAG)))
 	HGOTO_ERROR(H5E_CACHE, H5E_BADVALUE, NULL, "no write intent on file")
 
 #if H5AC__TRACE_FILE_ENABLED
-    /* For the protect call, only the addr and type id is really necessary
-     * in the trace file.  Include the size of the entry protected as a
-     * sanity check.  Also indicate whether the call was successful to
-     * catch occult errors.
+    /* For the protect call, only the addr, size, type id, and flags are 
+     * necessary in the trace file.  Also indicate whether the call was 
+     * successful to catch occult errors.
      */
-    if(NULL != (trace_file_ptr = H5C_get_trace_file_ptr(cache_ptr))) {
-
-	const char * rw_string;
-
-        if ( rw == H5AC_WRITE ) {
-
-	    rw_string = "H5AC_WRITE";
-
-	} else if ( rw == H5AC_READ ) {
-
-	    rw_string = "H5AC_READ";
-
-	} else {
-
-	    rw_string = "???";
-	}
-
-        sprintf(trace, "%s 0x%lx %d %s", FUNC, (unsigned long)addr,
-		(int)(type->id), rw_string);
-    }
+    if(NULL != (trace_file_ptr = H5C_get_trace_file_ptr(cache_ptr)))
+        sprintf(trace, "%s 0x%lx %d 0x%x", FUNC, (unsigned long)addr,
+		(int)(type->id), flags);
 #endif /* H5AC__TRACE_FILE_ENABLED */
 
-    if ( rw == H5AC_READ )
-	protect_flags |= H5C__READ_ONLY_FLAG;
-
-    if(NULL == (thing = H5C_protect(f, dxpl_id, H5AC_dxpl_id, type, addr, udata, protect_flags)))
-
+    if(NULL == (thing = H5C_protect(f, dxpl_id, type, addr, udata, flags)))
         HGOTO_ERROR(H5E_CACHE, H5E_CANTPROTECT, NULL, "H5C_protect() failed.")
 
 #if H5AC__TRACE_FILE_ENABLED
@@ -1438,8 +1424,8 @@ H5AC_unprotect(H5F_t *f, hid_t dxpl_id, const H5AC_class_t *type, haddr_t addr,
     HDassert(f->shared);
     HDassert(f->shared->cache);
     HDassert(type);
-    HDassert(type->clear);
-    HDassert(type->flush);
+    HDassert(type->deserialize);
+    HDassert(type->image_len);
     HDassert(H5F_addr_defined(addr));
     HDassert(thing);
     HDassert( ((H5AC_info_t *)thing)->addr == addr );
@@ -1462,9 +1448,11 @@ H5AC_unprotect(H5F_t *f, hid_t dxpl_id, const H5AC_class_t *type, haddr_t addr,
      *  the entry.
      */
     if(dirtied && !deleted) {
+        hbool_t		curr_compressed = FALSE; /* dummy for call */
         size_t		curr_size = 0;
+        size_t		curr_compressed_size = 0; /* dummy for call */
 
-        if((type->size)(f, thing, &curr_size) < 0)
+        if((type->image_len)(thing, &curr_size, &curr_compressed, &curr_compressed_size) < 0)
             HGOTO_ERROR(H5E_CACHE, H5E_CANTGETSIZE, FAIL, "Can't get size of thing")
 
         if(((H5AC_info_t *)thing)->size != curr_size)
@@ -1483,7 +1471,7 @@ H5AC_unprotect(H5F_t *f, hid_t dxpl_id, const H5AC_class_t *type, haddr_t addr,
     } /* end if */
 #endif /* H5_HAVE_PARALLEL */
 
-    if(H5C_unprotect(f, dxpl_id, H5AC_dxpl_id, type, addr, thing, flags) < 0)
+    if(H5C_unprotect(f, dxpl_id, type, addr, thing, flags) < 0)
         HGOTO_ERROR(H5E_CACHE, H5E_CANTUNPROTECT, FAIL, "H5C_unprotect() failed.")
 
 #ifdef H5_HAVE_PARALLEL
@@ -3419,7 +3407,7 @@ H5AC__propagate_and_apply_candidate_list(H5F_t  *f, hid_t dxpl_id)
         aux_ptr->write_permitted = TRUE;
 
         /* Apply the candidate list */
-        result = H5C_apply_candidate_list(f, dxpl_id, dxpl_id, cache_ptr, num_candidates,
+        result = H5C_apply_candidate_list(f, dxpl_id, cache_ptr, num_candidates,
             candidates_list_ptr, aux_ptr->mpi_rank, aux_ptr->mpi_size);
 
         /* Disable writes again */
@@ -3563,7 +3551,7 @@ H5AC__propagate_flushed_and_still_clean_entries_list(H5F_t  *f, hid_t dxpl_id)
         HDassert(H5SL_count(aux_ptr->c_slist_ptr) == 0);
     } /* end if */
     else {
-        if(H5AC__receive_and_apply_clean_list(f, dxpl_id, H5AC_dxpl_id) < 0)
+        if(H5AC__receive_and_apply_clean_list(f, dxpl_id) < 0)
             HGOTO_ERROR(H5E_CACHE, H5E_SYSTEM, FAIL, "Can't receive and/or process clean slist broadcast.")
     } /* end else */
 
@@ -3667,7 +3655,7 @@ done:
  */
 #ifdef H5_HAVE_PARALLEL
 static herr_t
-H5AC__receive_and_apply_clean_list(H5F_t *f, hid_t primary_dxpl_id, hid_t secondary_dxpl_id)
+H5AC__receive_and_apply_clean_list(H5F_t *f, hid_t dxpl_id)
 {
     H5AC_t             * cache_ptr;
     H5AC_aux_t         * aux_ptr;
@@ -3693,7 +3681,7 @@ H5AC__receive_and_apply_clean_list(H5F_t *f, hid_t primary_dxpl_id, hid_t second
 
     if(num_entries > 0)
         /* mark the indicated entries as clean */
-        if(H5C_mark_entries_as_clean(f, primary_dxpl_id, secondary_dxpl_id, (int32_t)num_entries, haddr_buf_ptr) < 0)
+        if(H5C_mark_entries_as_clean(f, dxpl_id, (int32_t)num_entries, haddr_buf_ptr) < 0)
             HGOTO_ERROR(H5E_CACHE, H5E_SYSTEM, FAIL, "Can't mark entries clean.")
 
     /* if it is defined, call the sync point done callback.  Note
@@ -3860,7 +3848,7 @@ H5AC__rsp__dist_md_write__flush(H5F_t *f, hid_t dxpl_id)
         aux_ptr->write_permitted = TRUE;
 
         /* Apply the candidate list */
-        result = H5C_apply_candidate_list(f, dxpl_id, dxpl_id, cache_ptr, num_entries,
+        result = H5C_apply_candidate_list(f, dxpl_id, cache_ptr, num_entries,
             haddr_buf_ptr, aux_ptr->mpi_rank, aux_ptr->mpi_size);
 
         /* Disable writes again */
@@ -4073,7 +4061,7 @@ H5AC__rsp__p0_only__flush(H5F_t *f, hid_t dxpl_id)
         aux_ptr->write_permitted = TRUE;
 
         /* Flush the cache */
-        result = H5C_flush_cache(f, dxpl_id, dxpl_id, H5AC__NO_FLAGS_SET);
+        result = H5C_flush_cache(f, dxpl_id, H5AC__NO_FLAGS_SET);
 
         /* Disable writes again */
         aux_ptr->write_permitted = FALSE;
@@ -4197,7 +4185,7 @@ H5AC__rsp__p0_only__flush_to_min_clean(H5F_t *f, hid_t dxpl_id)
             aux_ptr->write_permitted = TRUE;
 
             /* Flush the cache */
-            result = H5C_flush_to_min_clean(f, dxpl_id, H5AC_dxpl_id);
+            result = H5C_flush_to_min_clean(f, dxpl_id);
 
             /* Disable writes again */
             aux_ptr->write_permitted = FALSE;
diff --git a/src/H5ACpkg.h b/src/H5ACpkg.h
index 950bdea..28965d2 100644
--- a/src/H5ACpkg.h
+++ b/src/H5ACpkg.h
@@ -392,6 +392,12 @@ typedef struct H5AC_aux_t
 
 } H5AC_aux_t; /* struct H5AC_aux_t */
 
+/* Package scoped functions */
+H5_DLL herr_t H5AC_set_sync_point_done_callback(H5C_t *cache_ptr,
+    void (*sync_point_done)(int num_writes, haddr_t *written_entries_tbl));
+H5_DLL herr_t H5AC_set_write_done_callback(H5C_t * cache_ptr,
+    void (* write_done)(void));
+
 #endif /* H5_HAVE_PARALLEL */
 
 #endif /* _H5ACpkg_H */
diff --git a/src/H5ACprivate.h b/src/H5ACprivate.h
index a4e7c5a..584ce9d 100644
--- a/src/H5ACprivate.h
+++ b/src/H5ACprivate.h
@@ -79,6 +79,7 @@ typedef enum {
     H5AC_FARRAY_DBLOCK_ID, /*fixed array data block	     	     */
     H5AC_FARRAY_DBLK_PAGE_ID, /*fixed array data block page          */
     H5AC_SUPERBLOCK_ID, /* file superblock                           */
+    H5AC_DRVRINFO_ID,   /* driver info block (supplements superblock)*/
     H5AC_TEST_ID,	/*test entry -- not used for actual files    */
     H5AC_NTYPES		/* Number of types, must be last             */
 } H5AC_type_t;
@@ -91,6 +92,17 @@ typedef enum {
  * times for debugging purposes.
  *
  * Hence the following, somewhat odd set of #defines.
+ *
+ * NOTE: test/cache plays games with the f->shared->cache, and thus 
+ *       setting H5AC_DUMP_STATS_ON_CLOSE will generate constant, 
+ *	 irrelevant data when run with that test program.  See 
+ * 	 comments on setup_cache() / takedown_cache() in test/cache_common.c.
+ *       for details.
+ *
+ *	 If you need to dump stats at file close in test/cache.c,
+ *	 use the dump_stats parameter to takedown_cache(), or call 
+ *	 H5C_stats() directly.
+ *					JRM -- 4/12/15
  */
 #if H5C_COLLECT_CACHE_STATS
 
@@ -113,81 +125,48 @@ typedef enum {
 /*
  * Class methods pertaining to caching.	 Each type of cached object will
  * have a constant variable with permanent life-span that describes how
- * to cache the object.	 That variable will be of type H5AC_class_t and
- * have the following required fields...
- *
- * LOAD:	Loads an object from disk to memory.  The function
- *		should allocate some data structure and return it.
- *
- * FLUSH:	Writes some data structure back to disk.  It would be
- *		wise for the data structure to include dirty flags to
- *		indicate whether it really needs to be written.	 This
- *		function is also responsible for freeing memory allocated
- *		by the LOAD method if the DEST argument is non-zero (by
- *              calling the DEST method).
- *
- * DEST:	Just frees memory allocated by the LOAD method.
- *
- * CLEAR:	Just marks object as non-dirty.
- *
- * NOTIFY:	Notify client that an action on an entry has taken/will take
- *              place
- *
- * SIZE:	Report the size (on disk) of the specified cache object.
- *		Note that the space allocated on disk may not be contiguous.
+ * to cache the object.
  */
 
-#define H5AC_CALLBACK__NO_FLAGS_SET             H5C_CALLBACK__NO_FLAGS_SET
-#define H5AC_CALLBACK__SIZE_CHANGED_FLAG	H5C_CALLBACK__SIZE_CHANGED_FLAG
-#define H5AC_CALLBACK__MOVED_FLAG             H5C_CALLBACK__MOVED_FLAG
+#define H5AC__SERIALIZE_RESIZED_FLAG	H5C__SERIALIZE_RESIZED_FLAG
+#define H5AC__SERIALIZE_MOVED_FLAG	H5C__SERIALIZE_MOVED_FLAG
+#define H5AC__SERIALIZE_COMPRESSED_FLAG	H5C__SERIALIZE_COMPRESSED_FLAG
 
 /* Aliases for 'notify action' type & values */
 typedef H5C_notify_action_t     H5AC_notify_action_t;
 #define H5AC_NOTIFY_ACTION_AFTER_INSERT H5C_NOTIFY_ACTION_AFTER_INSERT
+#define H5AC_NOTIFY_ACTION_AFTER_LOAD   H5C_NOTIFY_ACTION_AFTER_LOAD
+#define H5AC_NOTIFY_ACTION_AFTER_FLUSH	H5C_NOTIFY_ACTION_AFTER_FLUSH
 #define H5AC_NOTIFY_ACTION_BEFORE_EVICT H5C_NOTIFY_ACTION_BEFORE_EVICT
 
-typedef H5C_load_func_t		H5AC_load_func_t;
-typedef H5C_flush_func_t	H5AC_flush_func_t;
-typedef H5C_dest_func_t		H5AC_dest_func_t;
-typedef H5C_clear_func_t	H5AC_clear_func_t;
-typedef H5C_notify_func_t	H5AC_notify_func_t;
-typedef H5C_size_func_t		H5AC_size_func_t;
+#define H5AC__CLASS_NO_FLAGS_SET 	H5C__CLASS_NO_FLAGS_SET
+#define H5AC__CLASS_SPECULATIVE_LOAD_FLAG H5C__CLASS_SPECULATIVE_LOAD_FLAG
+#define H5AC__CLASS_COMPRESSED_FLAG	H5C__CLASS_COMPRESSED_FLAG
 
-typedef H5C_class_t			H5AC_class_t;
+/* The following flags should only appear in test code */
+#define H5AC__CLASS_NO_IO_FLAG		H5C__CLASS_NO_IO_FLAG
+#define H5AC__CLASS_SKIP_READS		H5C__CLASS_SKIP_READS
+#define H5AC__CLASS_SKIP_WRITES		H5C__CLASS_SKIP_WRITES
 
+typedef H5C_get_load_size_func_t	H5AC_get_load_size_func_t;
+typedef H5C_deserialize_func_t		H5AC_deserialize_func_t;
+typedef H5C_image_len_func_t		H5AC_image_len_func_t;
 
-/* The H5AC_NSLOTS #define is now obsolete, as the metadata cache no longer
- * uses slots.  However I am leaving it in for now to avoid modifying the
- * interface between the metadata cache and the rest of HDF.  It should
- * be removed when we get to dealing with the size_hint parameter in
- * H5AC_create().
- *						JRM - 5/20/04
- *
- * Old comment on H5AC_NSLOTS follows:
- *
- * A cache has a certain number of entries.  Objects are mapped into a
- * cache entry by hashing the object's file address.  Each file has its
- * own cache, an array of slots.
- */
-#define H5AC_NSLOTS     10330           /* The library "likes" this number... */
-
-
-typedef H5C_cache_entry_t		H5AC_info_t;
+#define H5AC__SERIALIZE_NO_FLAGS_SET    H5C__SERIALIZE_NO_FLAGS_SET
+#define H5AC__SERIALIZE_RESIZED_FLAG    H5C__SERIALIZE_RESIZED_FLAG
+#define H5AC__SERIALIZE_MOVED_FLAG      H5C__SERIALIZE_MOVED_FLAG
 
+typedef H5C_pre_serialize_func_t	H5AC_pre_serialize_func_t;
+typedef H5C_serialize_func_t		H5AC_serialize_func_t;
+typedef H5C_notify_func_t		H5AC_notify_func_t;
+typedef H5C_free_icr_func_t		H5AC_free_icr_func_t;
+typedef H5C_clear_func_t		H5AC_clear_func_t;
+typedef H5C_get_fsf_size_t		H5AC_get_fsf_size_t;
 
-/*===----------------------------------------------------------------------===
- *                             Protect Types
- *===----------------------------------------------------------------------===
- *
- * These are for the wrapper functions to H5AC_protect. They specify what
- * type of operation you're planning on doing to the metadata. The
- * Flexible Parallel HDF5 locking can then act accordingly.
- */
+typedef H5C_class_t			H5AC_class_t;
 
-typedef enum H5AC_protect_t {
-    H5AC_WRITE,                 /* Protect object for writing                */
-    H5AC_READ                   /* Protect object for reading                */
-} H5AC_protect_t;
+/* Cache entry info */
+typedef H5C_cache_entry_t		H5AC_info_t;
 
 
 /* Typedef for metadata cache (defined in H5Cpkg.h) */
@@ -317,6 +296,7 @@ H5_DLLVAR hid_t H5AC_ind_dxpl_id;
 #define H5AC__FLUSH_CLEAR_ONLY_FLAG	  H5C__FLUSH_CLEAR_ONLY_FLAG
 #define H5AC__FLUSH_MARKED_ENTRIES_FLAG   H5C__FLUSH_MARKED_ENTRIES_FLAG
 #define H5AC__FLUSH_IGNORE_PROTECTED_FLAG H5C__FLUSH_IGNORE_PROTECTED_FLAG
+#define H5AC__READ_ONLY_FLAG		  H5C__READ_ONLY_FLAG
 #define H5AC__FREE_FILE_SPACE_FLAG	  H5C__FREE_FILE_SPACE_FLAG
 #define H5AC__TAKE_OWNERSHIP_FLAG         H5C__TAKE_OWNERSHIP_FLAG
 #define H5AC__FLUSH_LAST_FLAG		  H5C__FLUSH_LAST_FLAG
@@ -346,7 +326,7 @@ H5_DLL herr_t H5AC_insert_entry(H5F_t *f, hid_t dxpl_id, const H5AC_class_t *typ
 H5_DLL herr_t H5AC_pin_protected_entry(void *thing);
 H5_DLL herr_t H5AC_create_flush_dependency(void *parent_thing, void *child_thing);
 H5_DLL void * H5AC_protect(H5F_t *f, hid_t dxpl_id, const H5AC_class_t *type,
-    haddr_t addr, void *udata, H5AC_protect_t rw);
+    haddr_t addr, void *udata, unsigned flags);
 H5_DLL herr_t H5AC_resize_entry(void *thing, size_t new_size);
 H5_DLL herr_t H5AC_unpin_entry(void *thing);
 H5_DLL herr_t H5AC_destroy_flush_dependency(void *parent_thing, void *child_thing);
@@ -359,10 +339,6 @@ H5_DLL herr_t H5AC_move_entry(H5F_t *f, const H5AC_class_t *type,
 H5_DLL herr_t H5AC_dest(H5F_t *f, hid_t dxpl_id);
 H5_DLL herr_t H5AC_expunge_entry(H5F_t *f, hid_t dxpl_id,
     const H5AC_class_t *type, haddr_t addr, unsigned flags);
-H5_DLL herr_t H5AC_set_sync_point_done_callback(H5C_t *cache_ptr,
-    void (*sync_point_done)(int num_writes, haddr_t *written_entries_tbl));
-H5_DLL herr_t H5AC_set_write_done_callback(H5C_t * cache_ptr,
-                                           void (* write_done)(void));
 H5_DLL herr_t H5AC_get_cache_auto_resize_config(const H5AC_t * cache_ptr,
     H5AC_cache_config_t *config_ptr);
 H5_DLL herr_t H5AC_get_cache_size(H5AC_t *cache_ptr, size_t *max_size_ptr,
diff --git a/src/H5B.c b/src/H5B.c
index 765a57e..b1f3388 100644
--- a/src/H5B.c
+++ b/src/H5B.c
@@ -336,7 +336,7 @@ H5B_find(H5F_t *f, hid_t dxpl_id, const H5B_class_t *type, haddr_t addr, void *u
     cache_udata.f = f;
     cache_udata.type = type;
     cache_udata.rc_shared = rc_shared;
-    if(NULL == (bt = (H5B_t *)H5AC_protect(f, dxpl_id, H5AC_BT, addr, &cache_udata, H5AC_READ)))
+    if(NULL == (bt = (H5B_t *)H5AC_protect(f, dxpl_id, H5AC_BT, addr, &cache_udata, H5AC__READ_ONLY_FLAG)))
 	HGOTO_ERROR(H5E_BTREE, H5E_CANTPROTECT, FAIL, "unable to load B-tree node")
 
     rt = bt->nchildren;
@@ -485,7 +485,7 @@ H5B__split(H5F_t *f, hid_t dxpl_id, H5B_ins_ud_t *bt_ud, unsigned idx,
     cache_udata.f = f;
     cache_udata.type = shared->type;
     cache_udata.rc_shared = bt_ud->bt->rc_shared;
-    if(NULL == (split_bt_ud->bt = (H5B_t *)H5AC_protect(f, dxpl_id, H5AC_BT, split_bt_ud->addr, &cache_udata, H5AC_WRITE)))
+    if(NULL == (split_bt_ud->bt = (H5B_t *)H5AC_protect(f, dxpl_id, H5AC_BT, split_bt_ud->addr, &cache_udata, H5AC__NO_FLAGS_SET)))
 	HGOTO_ERROR(H5E_BTREE, H5E_CANTPROTECT, FAIL, "unable to protect B-tree")
     split_bt_ud->bt->level = bt_ud->bt->level;
 
@@ -518,7 +518,7 @@ H5B__split(H5F_t *f, hid_t dxpl_id, H5B_ins_ud_t *bt_ud, unsigned idx,
     if(H5F_addr_defined(bt_ud->bt->right)) {
         H5B_t   *tmp_bt;
 
-        if(NULL == (tmp_bt = (H5B_t *)H5AC_protect(f, dxpl_id, H5AC_BT, bt_ud->bt->right, &cache_udata, H5AC_WRITE)))
+        if(NULL == (tmp_bt = (H5B_t *)H5AC_protect(f, dxpl_id, H5AC_BT, bt_ud->bt->right, &cache_udata, H5AC__NO_FLAGS_SET)))
             HGOTO_ERROR(H5E_BTREE, H5E_CANTPROTECT, FAIL, "unable to load right sibling")
 
         tmp_bt->left = split_bt_ud->addr;
@@ -597,7 +597,7 @@ H5B_insert(H5F_t *f, hid_t dxpl_id, const H5B_class_t *type, haddr_t addr, void
     cache_udata.type = type;
     cache_udata.rc_shared = rc_shared;
     bt_ud.addr = addr;
-    if(NULL == (bt_ud.bt = (H5B_t *)H5AC_protect(f, dxpl_id, H5AC_BT, addr, &cache_udata, H5AC_WRITE)))
+    if(NULL == (bt_ud.bt = (H5B_t *)H5AC_protect(f, dxpl_id, H5AC_BT, addr, &cache_udata, H5AC__NO_FLAGS_SET)))
         HGOTO_ERROR(H5E_BTREE, H5E_CANTPROTECT, FAIL, "unable to locate root of B-tree")
 
     /* Insert the object */
@@ -901,7 +901,7 @@ H5B__insert_helper(H5F_t *f, hid_t dxpl_id, H5B_ins_ud_t *bt_ud,
              * Follow the minimum branch out of this node to a subtree.
              */
             child_bt_ud.addr = bt->child[idx];
-            if(NULL == (child_bt_ud.bt = (H5B_t *)H5AC_protect(f, dxpl_id, H5AC_BT, child_bt_ud.addr, &cache_udata, H5AC_WRITE)))
+            if(NULL == (child_bt_ud.bt = (H5B_t *)H5AC_protect(f, dxpl_id, H5AC_BT, child_bt_ud.addr, &cache_udata, H5AC__NO_FLAGS_SET)))
                 HGOTO_ERROR(H5E_BTREE, H5E_CANTPROTECT, H5B_INS_ERROR, "unable to load node")
 
             if((int)(my_ins = H5B__insert_helper(f, dxpl_id, &child_bt_ud, type,
@@ -947,7 +947,7 @@ H5B__insert_helper(H5F_t *f, hid_t dxpl_id, H5B_ins_ud_t *bt_ud,
             */
             idx = bt->nchildren - 1;
             child_bt_ud.addr = bt->child[idx];
-            if(NULL == (child_bt_ud.bt = (H5B_t *)H5AC_protect(f, dxpl_id, H5AC_BT, child_bt_ud.addr, &cache_udata, H5AC_WRITE)))
+            if(NULL == (child_bt_ud.bt = (H5B_t *)H5AC_protect(f, dxpl_id, H5AC_BT, child_bt_ud.addr, &cache_udata, H5AC__NO_FLAGS_SET)))
                 HGOTO_ERROR(H5E_BTREE, H5E_CANTPROTECT, H5B_INS_ERROR, "unable to load node")
 
             if((int)(my_ins = H5B__insert_helper(f, dxpl_id, &child_bt_ud, type,
@@ -1002,7 +1002,7 @@ H5B__insert_helper(H5F_t *f, hid_t dxpl_id, H5B_ins_ud_t *bt_ud,
 	 */
 	HDassert(idx < bt->nchildren);
 	child_bt_ud.addr = bt->child[idx];
-        if(NULL == (child_bt_ud.bt = (H5B_t *)H5AC_protect(f, dxpl_id, H5AC_BT, child_bt_ud.addr, &cache_udata, H5AC_WRITE)))
+        if(NULL == (child_bt_ud.bt = (H5B_t *)H5AC_protect(f, dxpl_id, H5AC_BT, child_bt_ud.addr, &cache_udata, H5AC__NO_FLAGS_SET)))
             HGOTO_ERROR(H5E_BTREE, H5E_CANTPROTECT, H5B_INS_ERROR, "unable to load node")
 
 	if((int)(my_ins = H5B__insert_helper(f, dxpl_id, &child_bt_ud, type,
@@ -1164,7 +1164,7 @@ H5B__iterate_helper(H5F_t *f, hid_t dxpl_id, const H5B_class_t *type, haddr_t ad
     cache_udata.f = f;
     cache_udata.type = type;
     cache_udata.rc_shared = rc_shared;
-    if(NULL == (bt = (H5B_t *)H5AC_protect(f, dxpl_id, H5AC_BT, addr, &cache_udata, H5AC_READ)))
+    if(NULL == (bt = (H5B_t *)H5AC_protect(f, dxpl_id, H5AC_BT, addr, &cache_udata, H5AC__READ_ONLY_FLAG)))
         HGOTO_ERROR(H5E_BTREE, H5E_CANTPROTECT, H5_ITER_ERROR, "unable to load B-tree node")
 
     /* Iterate over node's children */
@@ -1287,7 +1287,7 @@ H5B__remove_helper(H5F_t *f, hid_t dxpl_id, haddr_t addr, const H5B_class_t *typ
     cache_udata.f = f;
     cache_udata.type = type;
     cache_udata.rc_shared = rc_shared;
-    if(NULL == (bt = (H5B_t *)H5AC_protect(f, dxpl_id, H5AC_BT, addr, &cache_udata, H5AC_WRITE)))
+    if(NULL == (bt = (H5B_t *)H5AC_protect(f, dxpl_id, H5AC_BT, addr, &cache_udata, H5AC__NO_FLAGS_SET)))
 	HGOTO_ERROR(H5E_BTREE, H5E_CANTPROTECT, H5B_INS_ERROR, "unable to load B-tree node")
 
     rt = bt->nchildren;
@@ -1387,7 +1387,7 @@ H5B__remove_helper(H5F_t *f, hid_t dxpl_id, haddr_t addr, const H5B_class_t *typ
                  * "critical" for any child in its node to maintain this
                  * consistency (and avoid breaking key/child consistency) */
                 if(H5F_addr_defined(bt->left)) {
-                    if(NULL == (sibling = (H5B_t *)H5AC_protect(f, dxpl_id, H5AC_BT, bt->left, &cache_udata, H5AC_WRITE)))
+                    if(NULL == (sibling = (H5B_t *)H5AC_protect(f, dxpl_id, H5AC_BT, bt->left, &cache_udata, H5AC__NO_FLAGS_SET)))
                         HGOTO_ERROR(H5E_BTREE, H5E_CANTPROTECT, H5B_INS_ERROR, "unable to load node from tree")
 
                     /* Copy right-most key from deleted node to right-most key
@@ -1404,7 +1404,7 @@ H5B__remove_helper(H5F_t *f, hid_t dxpl_id, haddr_t addr, const H5B_class_t *typ
                     sibling = NULL;   /* Make certain future references will be caught */
                 } /* end if */
                 if(H5F_addr_defined(bt->right)) {
-                    if(NULL == (sibling = (H5B_t *)H5AC_protect(f, dxpl_id, H5AC_BT, bt->right, &cache_udata, H5AC_WRITE)))
+                    if(NULL == (sibling = (H5B_t *)H5AC_protect(f, dxpl_id, H5AC_BT, bt->right, &cache_udata, H5AC__NO_FLAGS_SET)))
                         HGOTO_ERROR(H5E_BTREE, H5E_CANTPROTECT, H5B_INS_ERROR, "unable to unlink node from tree")
 
                     /* Copy left-most key from deleted node to left-most key in
@@ -1524,7 +1524,7 @@ H5B__remove_helper(H5F_t *f, hid_t dxpl_id, haddr_t addr, const H5B_class_t *typ
         HDassert(level > 0);
 
         /* Update the rightmost key in the left sibling */
-        if(NULL == (sibling = (H5B_t *)H5AC_protect(f, dxpl_id, H5AC_BT, bt->left, &cache_udata, H5AC_WRITE)))
+        if(NULL == (sibling = (H5B_t *)H5AC_protect(f, dxpl_id, H5AC_BT, bt->left, &cache_udata, H5AC__NO_FLAGS_SET)))
             HGOTO_ERROR(H5E_BTREE, H5E_CANTPROTECT, H5B_INS_ERROR, "unable to protect node")
 
         HDmemcpy(H5B_NKEY(sibling, shared, sibling->nchildren),
@@ -1539,7 +1539,7 @@ H5B__remove_helper(H5F_t *f, hid_t dxpl_id, haddr_t addr, const H5B_class_t *typ
         HDassert(level > 0);
 
         /* Update the lefttmost key in the right sibling */
-        if(NULL == (sibling = (H5B_t *)H5AC_protect(f, dxpl_id, H5AC_BT, bt->right, &cache_udata, H5AC_WRITE)))
+        if(NULL == (sibling = (H5B_t *)H5AC_protect(f, dxpl_id, H5AC_BT, bt->right, &cache_udata, H5AC__NO_FLAGS_SET)))
             HGOTO_ERROR(H5E_BTREE, H5E_CANTPROTECT, H5B_INS_ERROR, "unable to protect node")
 
         HDmemcpy(H5B_NKEY(sibling, shared, 0),
@@ -1646,7 +1646,7 @@ H5B_delete(H5F_t *f, hid_t dxpl_id, const H5B_class_t *type, haddr_t addr, void
     cache_udata.f = f;
     cache_udata.type = type;
     cache_udata.rc_shared = rc_shared;
-    if(NULL == (bt = (H5B_t *)H5AC_protect(f, dxpl_id, H5AC_BT, addr, &cache_udata, H5AC_WRITE)))
+    if(NULL == (bt = (H5B_t *)H5AC_protect(f, dxpl_id, H5AC_BT, addr, &cache_udata, H5AC__NO_FLAGS_SET)))
         HGOTO_ERROR(H5E_BTREE, H5E_CANTPROTECT, FAIL, "unable to load B-tree node")
 
     /* Iterate over all children in tree, deleting them */
@@ -1908,7 +1908,7 @@ H5B__get_info_helper(H5F_t *f, hid_t dxpl_id, const H5B_class_t *type, haddr_t a
     cache_udata.f = f;
     cache_udata.type = type;
     cache_udata.rc_shared = rc_shared;
-    if(NULL == (bt = (H5B_t *)H5AC_protect(f, dxpl_id, H5AC_BT, addr, &cache_udata, H5AC_READ)))
+    if(NULL == (bt = (H5B_t *)H5AC_protect(f, dxpl_id, H5AC_BT, addr, &cache_udata, H5AC__READ_ONLY_FLAG)))
 	HGOTO_ERROR(H5E_BTREE, H5E_CANTPROTECT, FAIL, "unable to load B-tree node")
 
     /* Cache information from this node */
@@ -1932,7 +1932,7 @@ H5B__get_info_helper(H5F_t *f, hid_t dxpl_id, const H5B_class_t *type, haddr_t a
     while(H5F_addr_defined(next_addr)) {
         /* Protect the next node to the right */
         addr = next_addr;
-        if(NULL == (bt = (H5B_t *)H5AC_protect(f, dxpl_id, H5AC_BT, addr, &cache_udata, H5AC_READ)))
+        if(NULL == (bt = (H5B_t *)H5AC_protect(f, dxpl_id, H5AC_BT, addr, &cache_udata, H5AC__READ_ONLY_FLAG)))
             HGOTO_ERROR(H5E_BTREE, H5E_CANTPROTECT, FAIL, "B-tree node")
 
         /* Cache information from this node */
@@ -2059,7 +2059,7 @@ H5B_valid(H5F_t *f, hid_t dxpl_id, const H5B_class_t *type, haddr_t addr)
     cache_udata.f = f;
     cache_udata.type = type;
     cache_udata.rc_shared = rc_shared;
-    if(NULL == (bt = (H5B_t *)H5AC_protect(f, dxpl_id, H5AC_BT, addr, &cache_udata, H5AC_READ)))
+    if(NULL == (bt = (H5B_t *)H5AC_protect(f, dxpl_id, H5AC_BT, addr, &cache_udata, H5AC__READ_ONLY_FLAG)))
 	HGOTO_ERROR(H5E_BTREE, H5E_CANTPROTECT, FAIL, "unable to protect B-tree node")
 
 done:
diff --git a/src/H5B2.c b/src/H5B2.c
index 0c0f24f..7b5aa16 100644
--- a/src/H5B2.c
+++ b/src/H5B2.c
@@ -155,8 +155,9 @@ H5B2_create(H5F_t *f, hid_t dxpl_id, const H5B2_create_t *cparam, void *ctx_udat
 
     /* Look up the B-tree header */
     cache_udata.f = f;
+    cache_udata.addr = hdr_addr;
     cache_udata.ctx_udata = ctx_udata;
-    if(NULL == (hdr = (H5B2_hdr_t *)H5AC_protect(f, dxpl_id, H5AC_BT2_HDR, hdr_addr, &cache_udata, H5AC_WRITE)))
+    if(NULL == (hdr = (H5B2_hdr_t *)H5AC_protect(f, dxpl_id, H5AC_BT2_HDR, hdr_addr, &cache_udata, H5AC__NO_FLAGS_SET)))
         HGOTO_ERROR(H5E_BTREE, H5E_CANTPROTECT, NULL, "unable to load B-tree header")
 
     /* Point v2 B-tree wrapper at header and bump it's ref count */
@@ -215,8 +216,9 @@ H5B2_open(H5F_t *f, hid_t dxpl_id, haddr_t addr, void *ctx_udata)
 
     /* Look up the B-tree header */
     cache_udata.f = f;
+    cache_udata.addr = addr;
     cache_udata.ctx_udata = ctx_udata;
-    if(NULL == (hdr = (H5B2_hdr_t *)H5AC_protect(f, dxpl_id, H5AC_BT2_HDR, addr, &cache_udata, H5AC_READ)))
+    if(NULL == (hdr = (H5B2_hdr_t *)H5AC_protect(f, dxpl_id, H5AC_BT2_HDR, addr, &cache_udata, H5AC__READ_ONLY_FLAG)))
 	HGOTO_ERROR(H5E_BTREE, H5E_CANTPROTECT, NULL, "unable to load B-tree header")
 
     /* Check for pending heap deletion */
@@ -479,7 +481,7 @@ H5B2_find(H5B2_t *bt2, hid_t dxpl_id, void *udata, H5B2_found_t op,
         H5B2_node_ptr_t next_node_ptr;      /* Node pointer info for next node */
 
         /* Lock B-tree current node */
-        if(NULL == (internal = H5B2__protect_internal(hdr, dxpl_id, curr_node_ptr.addr, curr_node_ptr.node_nrec, depth, H5AC_READ)))
+        if(NULL == (internal = H5B2__protect_internal(hdr, dxpl_id, curr_node_ptr.addr, curr_node_ptr.node_nrec, depth, H5AC__READ_ONLY_FLAG)))
             HGOTO_ERROR(H5E_BTREE, H5E_CANTPROTECT, FAIL, "unable to load B-tree internal node")
 
         /* Locate node pointer for child */
@@ -542,7 +544,7 @@ H5B2_find(H5B2_t *bt2, hid_t dxpl_id, void *udata, H5B2_found_t op,
         H5B2_leaf_t *leaf;          /* Pointer to leaf node in B-tree */
 
         /* Lock B-tree leaf node */
-        if(NULL == (leaf = H5B2__protect_leaf(hdr, dxpl_id, curr_node_ptr.addr, curr_node_ptr.node_nrec, H5AC_READ)))
+        if(NULL == (leaf = H5B2__protect_leaf(hdr, dxpl_id, curr_node_ptr.addr, curr_node_ptr.node_nrec, H5AC__READ_ONLY_FLAG)))
             HGOTO_ERROR(H5E_BTREE, H5E_CANTPROTECT, FAIL, "unable to protect B-tree leaf node")
 
         /* Locate record */
@@ -662,7 +664,7 @@ H5B2_index(H5B2_t *bt2, hid_t dxpl_id, H5_iter_order_t order, hsize_t idx,
         unsigned u;                         /* Local index variable */
 
         /* Lock B-tree current node */
-        if(NULL == (internal = H5B2__protect_internal(hdr, dxpl_id, curr_node_ptr.addr, curr_node_ptr.node_nrec, depth, H5AC_READ)))
+        if(NULL == (internal = H5B2__protect_internal(hdr, dxpl_id, curr_node_ptr.addr, curr_node_ptr.node_nrec, depth, H5AC__READ_ONLY_FLAG)))
             HGOTO_ERROR(H5E_BTREE, H5E_CANTPROTECT, FAIL, "unable to load B-tree internal node")
 
         /* Search for record with correct index */
@@ -734,7 +736,7 @@ H5B2_index(H5B2_t *bt2, hid_t dxpl_id, H5_iter_order_t order, hsize_t idx,
         H5B2_leaf_t *leaf;          /* Pointer to leaf node in B-tree */
 
         /* Lock B-tree leaf node */
-        if(NULL == (leaf = H5B2__protect_leaf(hdr, dxpl_id, curr_node_ptr.addr, curr_node_ptr.node_nrec, H5AC_READ)))
+        if(NULL == (leaf = H5B2__protect_leaf(hdr, dxpl_id, curr_node_ptr.addr, curr_node_ptr.node_nrec, H5AC__READ_ONLY_FLAG)))
             HGOTO_ERROR(H5E_BTREE, H5E_CANTPROTECT, FAIL, "unable to protect B-tree leaf node")
 
         /* Sanity check index */
@@ -1070,7 +1072,7 @@ H5B2_modify(H5B2_t *bt2, hid_t dxpl_id, void *udata, H5B2_modify_t op,
         H5B2_node_ptr_t next_node_ptr;      /* Node pointer info for next node */
 
         /* Lock B-tree current node */
-        if(NULL == (internal = H5B2__protect_internal(hdr, dxpl_id, curr_node_ptr.addr, curr_node_ptr.node_nrec, depth, H5AC_WRITE)))
+        if(NULL == (internal = H5B2__protect_internal(hdr, dxpl_id, curr_node_ptr.addr, curr_node_ptr.node_nrec, depth, H5AC__NO_FLAGS_SET)))
             HGOTO_ERROR(H5E_BTREE, H5E_CANTPROTECT, FAIL, "unable to load B-tree internal node")
 
         /* Locate node pointer for child */
@@ -1142,7 +1144,7 @@ H5B2_modify(H5B2_t *bt2, hid_t dxpl_id, void *udata, H5B2_modify_t op,
         hbool_t changed = FALSE;/* Whether the 'modify' callback changed the record */
 
         /* Lock B-tree leaf node */
-        if(NULL == (leaf = H5B2__protect_leaf(hdr, dxpl_id, curr_node_ptr.addr, curr_node_ptr.node_nrec, H5AC_WRITE)))
+        if(NULL == (leaf = H5B2__protect_leaf(hdr, dxpl_id, curr_node_ptr.addr, curr_node_ptr.node_nrec, H5AC__NO_FLAGS_SET)))
             HGOTO_ERROR(H5E_BTREE, H5E_CANTPROTECT, FAIL, "unable to protect B-tree leaf node")
 
         /* Locate record */
@@ -1276,7 +1278,7 @@ H5B2_close(H5B2_t *bt2, hid_t dxpl_id)
 
         /* Lock the v2 B-tree header into memory */
         /* (OK to pass in NULL for callback context, since we know the header must be in the cache) */
-        if(NULL == (hdr = (H5B2_hdr_t *)H5AC_protect(bt2->f, dxpl_id, H5AC_BT2_HDR, bt2_addr, NULL, H5AC_WRITE)))
+        if(NULL == (hdr = (H5B2_hdr_t *)H5AC_protect(bt2->f, dxpl_id, H5AC_BT2_HDR, bt2_addr, NULL, H5AC__NO_FLAGS_SET)))
             HGOTO_ERROR(H5E_BTREE, H5E_CANTPROTECT, FAIL, "unable to protect v2 B-tree header")
 
         /* Set the shared v2 B-tree header's file context for this operation */
@@ -1352,8 +1354,9 @@ H5B2_delete(H5F_t *f, hid_t dxpl_id, haddr_t addr, void *ctx_udata,
 HDfprintf(stderr, "%s: addr = %a\n", FUNC, addr);
 #endif /* QAK */
     cache_udata.f = f;
+    cache_udata.addr = addr;
     cache_udata.ctx_udata = ctx_udata;
-    if(NULL == (hdr = (H5B2_hdr_t *)H5AC_protect(f, dxpl_id, H5AC_BT2_HDR, addr, &cache_udata, H5AC_WRITE)))
+    if(NULL == (hdr = (H5B2_hdr_t *)H5AC_protect(f, dxpl_id, H5AC_BT2_HDR, addr, &cache_udata, H5AC__NO_FLAGS_SET)))
         HGOTO_ERROR(H5E_BTREE, H5E_CANTPROTECT, FAIL, "unable to protect v2 B-tree header")
 
     /* Remember the callback & context for later */
diff --git a/src/H5B2cache.c b/src/H5B2cache.c
index 3b30e02..64e304c 100644
--- a/src/H5B2cache.c
+++ b/src/H5B2cache.c
@@ -37,7 +37,6 @@
 #include "H5private.h"		/* Generic Functions			*/
 #include "H5B2pkg.h"		/* v2 B-trees				*/
 #include "H5Eprivate.h"		/* Error handling		  	*/
-#include "H5MFprivate.h"	/* File memory management		*/
 #include "H5WBprivate.h"        /* Wrapped Buffers                      */
 
 
@@ -50,9 +49,6 @@
 #define H5B2_INT_VERSION 0              /* Internal node */
 #define H5B2_LEAF_VERSION 0             /* Leaf node */
 
-/* Size of stack buffer for serialized headers */
-#define H5B2_HDR_BUF_SIZE               128
-
 
 /******************/
 /* Local Typedefs */
@@ -69,22 +65,32 @@
 /********************/
 
 /* Metadata cache callbacks */
-static H5B2_hdr_t *H5B2__cache_hdr_load(H5F_t *f, hid_t dxpl_id, haddr_t addr, void *udata);
-static herr_t H5B2__cache_hdr_flush(H5F_t *f, hid_t dxpl_id, hbool_t destroy, haddr_t addr, H5B2_hdr_t *hdr, unsigned H5_ATTR_UNUSED * flags_ptr);
-static herr_t H5B2__cache_hdr_dest(H5F_t *f, H5B2_hdr_t *hdr);
-static herr_t H5B2__cache_hdr_clear(H5F_t *f, H5B2_hdr_t *hdr, hbool_t destroy);
-static herr_t H5B2__cache_hdr_size(const H5F_t *f, const H5B2_hdr_t *hdr, size_t *size_ptr);
-static H5B2_internal_t *H5B2__cache_internal_load(H5F_t *f, hid_t dxpl_id, haddr_t addr, void *udata);
-static herr_t H5B2__cache_internal_flush(H5F_t *f, hid_t dxpl_id, hbool_t destroy, haddr_t addr, H5B2_internal_t *i, unsigned H5_ATTR_UNUSED * flags_ptr);
-static herr_t H5B2__cache_internal_dest(H5F_t *f, H5B2_internal_t *internal);
-static herr_t H5B2__cache_internal_clear(H5F_t *f, H5B2_internal_t *i, hbool_t destroy);
-static herr_t H5B2__cache_internal_size(const H5F_t *f, const H5B2_internal_t *i, size_t *size_ptr);
-static H5B2_leaf_t *H5B2__cache_leaf_load(H5F_t *f, hid_t dxpl_id, haddr_t addr, void *udata);
-static herr_t H5B2__cache_leaf_flush(H5F_t *f, hid_t dxpl_id, hbool_t destroy, haddr_t addr, H5B2_leaf_t *l, unsigned H5_ATTR_UNUSED * flags_ptr);
-static herr_t H5B2__cache_leaf_dest(H5F_t *f, H5B2_leaf_t *leaf);
-static herr_t H5B2__cache_leaf_clear(H5F_t *f, H5B2_leaf_t *l, hbool_t destroy);
-static herr_t H5B2__cache_leaf_size(const H5F_t *f, const H5B2_leaf_t *l, size_t *size_ptr);
-
+static herr_t H5B2__cache_hdr_get_load_size(const void *udata, size_t *image_len);
+static void *H5B2__cache_hdr_deserialize(const void *image, size_t len,
+    void *udata, hbool_t *dirty);
+static herr_t H5B2__cache_hdr_image_len(const void *thing, size_t *image_len,
+    hbool_t *compressed_ptr, size_t *compressed_image_len_ptr);
+static herr_t H5B2__cache_hdr_serialize(const H5F_t *f, void *image, size_t len,
+    void *thing);
+static herr_t H5B2__cache_hdr_free_icr(void *thing);
+
+static herr_t H5B2__cache_int_get_load_size(const void *udata, size_t *image_len);
+static void *H5B2__cache_int_deserialize(const void *image, size_t len,
+    void *udata, hbool_t *dirty);
+static herr_t H5B2__cache_int_image_len(const void *thing, size_t *image_len,
+    hbool_t *compressed_ptr, size_t *compressed_image_len_ptr);
+static herr_t H5B2__cache_int_serialize(const H5F_t *f, void *image, size_t len,
+    void *thing);
+static herr_t H5B2__cache_int_free_icr(void *thing);
+
+static herr_t H5B2__cache_leaf_get_load_size(const void *udata, size_t *image_len);
+static void *H5B2__cache_leaf_deserialize(const void *image, size_t len,
+    void *udata, hbool_t *dirty);
+static herr_t H5B2__cache_leaf_image_len(const void *thing, size_t *image_len,
+    hbool_t *compressed_ptr, size_t *compressed_image_len_ptr);
+static herr_t H5B2__cache_leaf_serialize(const H5F_t *f, void *image, size_t len,
+    void *thing);
+static herr_t H5B2__cache_leaf_free_icr(void *thing);
 
 /*********************/
 /* Package Variables */
@@ -92,35 +98,53 @@ static herr_t H5B2__cache_leaf_size(const H5F_t *f, const H5B2_leaf_t *l, size_t
 
 /* H5B2 inherits cache-like properties from H5AC */
 const H5AC_class_t H5AC_BT2_HDR[1] = {{
-    H5AC_BT2_HDR_ID,
-    (H5AC_load_func_t)H5B2__cache_hdr_load,
-    (H5AC_flush_func_t)H5B2__cache_hdr_flush,
-    (H5AC_dest_func_t)H5B2__cache_hdr_dest,
-    (H5AC_clear_func_t)H5B2__cache_hdr_clear,
-    (H5AC_notify_func_t)NULL,
-    (H5AC_size_func_t)H5B2__cache_hdr_size,
+    H5AC_BT2_HDR_ID,                    /* Metadata client ID */
+    "v2 B-tree header",                 /* Metadata client name (for debugging) */
+    H5FD_MEM_BTREE,                     /* File space memory type for client */
+    H5AC__CLASS_NO_FLAGS_SET,           /* Client class behavior flags */
+    H5B2__cache_hdr_get_load_size,      /* 'get_load_size' callback */
+    H5B2__cache_hdr_deserialize,        /* 'deserialize' callback */
+    H5B2__cache_hdr_image_len,          /* 'image_len' callback */
+    NULL,                               /* 'pre_serialize' callback */
+    H5B2__cache_hdr_serialize,          /* 'serialize' callback */
+    NULL,                               /* 'notify' callback */
+    H5B2__cache_hdr_free_icr,           /* 'free_icr' callback */
+    NULL,				/* 'clear' callback */
+    NULL,				/* 'fsf_size' callback */
 }};
 
 /* H5B2 inherits cache-like properties from H5AC */
 const H5AC_class_t H5AC_BT2_INT[1] = {{
-    H5AC_BT2_INT_ID,
-    (H5AC_load_func_t)H5B2__cache_internal_load,
-    (H5AC_flush_func_t)H5B2__cache_internal_flush,
-    (H5AC_dest_func_t)H5B2__cache_internal_dest,
-    (H5AC_clear_func_t)H5B2__cache_internal_clear,
-    (H5AC_notify_func_t)NULL,
-    (H5AC_size_func_t)H5B2__cache_internal_size,
+    H5AC_BT2_INT_ID,                    /* Metadata client ID */
+    "v2 B-tree internal node",          /* Metadata client name (for debugging) */
+    H5FD_MEM_BTREE,                     /* File space memory type for client */
+    H5AC__CLASS_NO_FLAGS_SET,           /* Client class behavior flags */
+    H5B2__cache_int_get_load_size,      /* 'get_load_size' callback */
+    H5B2__cache_int_deserialize,        /* 'deserialize' callback */
+    H5B2__cache_int_image_len,          /* 'image_len' callback */
+    NULL,                               /* 'pre_serialize' callback */
+    H5B2__cache_int_serialize,          /* 'serialize' callback */
+    NULL,                               /* 'notify' callback */
+    H5B2__cache_int_free_icr,           /* 'free_icr' callback */
+    NULL,				/* 'clear' callback */
+    NULL,				/* 'fsf_size' callback */
 }};
 
 /* H5B2 inherits cache-like properties from H5AC */
 const H5AC_class_t H5AC_BT2_LEAF[1] = {{
-    H5AC_BT2_LEAF_ID,
-    (H5AC_load_func_t)H5B2__cache_leaf_load,
-    (H5AC_flush_func_t)H5B2__cache_leaf_flush,
-    (H5AC_dest_func_t)H5B2__cache_leaf_dest,
-    (H5AC_clear_func_t)H5B2__cache_leaf_clear,
-    (H5AC_notify_func_t)NULL,
-    (H5AC_size_func_t)H5B2__cache_leaf_size,
+    H5AC_BT2_LEAF_ID,                   /* Metadata client ID */
+    "v2 B-tree leaf node",              /* Metadata client name (for debugging) */
+    H5FD_MEM_BTREE,                     /* File space memory type for client */
+    H5AC__CLASS_NO_FLAGS_SET,           /* Client class behavior flags */
+    H5B2__cache_leaf_get_load_size,     /* 'get_load_size' callback */
+    H5B2__cache_leaf_deserialize,       /* 'deserialize' callback */
+    H5B2__cache_leaf_image_len,         /* 'image_len' callback */
+    NULL,                               /* 'pre_serialize' callback */
+    H5B2__cache_leaf_serialize,         /* 'serialize' callback */
+    NULL,                               /* 'notify' callback */
+    H5B2__cache_leaf_free_icr,          /* 'free_icr' callback */
+    NULL,				/* 'clear' callback */
+    NULL,				/* 'fsf_size' callback */
 }};
 
 
@@ -136,7 +160,38 @@ const H5AC_class_t H5AC_BT2_LEAF[1] = {{
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5B2__cache_hdr_load
+ * Function:    H5B2__cache_hdr_get_load_size
+ *
+ * Purpose:     Compute the size of the data structure on disk.
+ *
+ * Return:      Non-negative on success/Negative on failure
+ *
+ * Programmer:  Quincey Koziol
+ *              koziol@hdfgroup.org
+ *              May 18, 2010
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+H5B2__cache_hdr_get_load_size(const void *_udata, size_t *image_len)
+{
+    const H5B2_hdr_cache_ud_t *udata = (const H5B2_hdr_cache_ud_t *)_udata; /* User data for callback */
+
+    FUNC_ENTER_STATIC_NOERR
+
+    /* Check arguments */
+    HDassert(udata);
+    HDassert(image_len);
+
+    /* Set the image length size */
+    *image_len = H5B2_HEADER_SIZE_FILE(udata->f);
+
+    FUNC_LEAVE_NOAPI(SUCCEED)
+} /* end H5B2__cache_hdr_get_load_size() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:	H5B2__cache_hdr_deserialize
  *
  * Purpose:	Loads a B-tree header from the disk.
  *
@@ -149,8 +204,9 @@ const H5AC_class_t H5AC_BT2_LEAF[1] = {{
  *
  *-------------------------------------------------------------------------
  */
-static H5B2_hdr_t *
-H5B2__cache_hdr_load(H5F_t *f, hid_t dxpl_id, haddr_t addr, void *_udata)
+static void *
+H5B2__cache_hdr_deserialize(const void *_image, size_t H5_ATTR_UNUSED len,
+    void *_udata, hbool_t H5_ATTR_UNUSED *dirty)
 {
     H5B2_hdr_t		*hdr = NULL;    /* B-tree header */
     H5B2_hdr_cache_ud_t *udata = (H5B2_hdr_cache_ud_t *)_udata;
@@ -159,78 +215,59 @@ H5B2__cache_hdr_load(H5F_t *f, hid_t dxpl_id, haddr_t addr, void *_udata)
     uint16_t            depth;          /* Depth of B-tree */
     uint32_t            stored_chksum;  /* Stored metadata checksum value */
     uint32_t            computed_chksum; /* Computed metadata checksum value */
-    H5WB_t              *wb = NULL;     /* Wrapped buffer for header data */
-    uint8_t             hdr_buf[H5B2_HDR_BUF_SIZE]; /* Buffer for header */
-    uint8_t		*buf;           /* Pointer to header buffer */
-    const uint8_t	*p;             /* Pointer into raw data buffer */
+    const uint8_t	*image = (const uint8_t *)_image;       /* Pointer into raw data buffer */
     H5B2_hdr_t		*ret_value;     /* Return value */
 
     FUNC_ENTER_STATIC
 
     /* Check arguments */
-    HDassert(f);
-    HDassert(H5F_addr_defined(addr));
+    HDassert(image);
     HDassert(udata);
 
     /* Allocate new B-tree header and reset cache info */
     if(NULL == (hdr = H5B2__hdr_alloc(udata->f)))
         HGOTO_ERROR(H5E_BTREE, H5E_CANTALLOC, NULL, "allocation failed for B-tree header")
 
-    /* Wrap the local buffer for serialized header info */
-    if(NULL == (wb = H5WB_wrap(hdr_buf, sizeof(hdr_buf))))
-        HGOTO_ERROR(H5E_BTREE, H5E_CANTINIT, NULL, "can't wrap buffer")
-
-    /* Get a pointer to a buffer that's large enough for header */
-    if(NULL == (buf = (uint8_t *)H5WB_actual(wb, hdr->hdr_size)))
-        HGOTO_ERROR(H5E_BTREE, H5E_NOSPACE, NULL, "can't get actual buffer")
-
-    /* Read header from disk */
-    if(H5F_block_read(f, H5FD_MEM_BTREE, addr, hdr->hdr_size, dxpl_id, buf) < 0)
-        HGOTO_ERROR(H5E_BTREE, H5E_READERROR, NULL, "can't read B-tree header")
-
-    /* Get temporary pointer to serialized header */
-    p = buf;
-
     /* Magic number */
-    if(HDmemcmp(p, H5B2_HDR_MAGIC, (size_t)H5_SIZEOF_MAGIC))
+    if(HDmemcmp(image, H5B2_HDR_MAGIC, (size_t)H5_SIZEOF_MAGIC))
 	HGOTO_ERROR(H5E_BTREE, H5E_BADVALUE, NULL, "wrong B-tree header signature")
-    p += H5_SIZEOF_MAGIC;
+    image += H5_SIZEOF_MAGIC;
 
     /* Version */
-    if(*p++ != H5B2_HDR_VERSION)
+    if(*image++ != H5B2_HDR_VERSION)
 	HGOTO_ERROR(H5E_BTREE, H5E_BADRANGE, NULL, "wrong B-tree header version")
 
     /* B-tree class */
-    id = (H5B2_subid_t)*p++;
+    id = (H5B2_subid_t)*image++;
     if(id >= H5B2_NUM_BTREE_ID)
         HGOTO_ERROR(H5E_BTREE, H5E_BADTYPE, NULL, "incorrect B-tree type")
 
     /* Node size (in bytes) */
-    UINT32DECODE(p, cparam.node_size);
+    UINT32DECODE(image, cparam.node_size);
 
     /* Raw key size (in bytes) */
-    UINT16DECODE(p, cparam.rrec_size);
+    UINT16DECODE(image, cparam.rrec_size);
 
     /* Depth of tree */
-    UINT16DECODE(p, depth);
+    UINT16DECODE(image, depth);
 
     /* Split & merge %s */
-    cparam.split_percent = *p++;
-    cparam.merge_percent = *p++;
+    cparam.split_percent = *image++;
+    cparam.merge_percent = *image++;
 
     /* Root node pointer */
-    H5F_addr_decode(udata->f, (const uint8_t **)&p, &(hdr->root.addr));
-    UINT16DECODE(p, hdr->root.node_nrec);
-    H5F_DECODE_LENGTH(udata->f, p, hdr->root.all_nrec);
+    H5F_addr_decode(udata->f, (const uint8_t **)&image, &(hdr->root.addr));
+    UINT16DECODE(image, hdr->root.node_nrec);
+    H5F_DECODE_LENGTH(udata->f, image, hdr->root.all_nrec);
 
     /* Metadata checksum */
-    UINT32DECODE(p, stored_chksum);
+    UINT32DECODE(image, stored_chksum);
 
     /* Sanity check */
-    HDassert((size_t)(p - (const uint8_t *)buf) == hdr->hdr_size);
+    HDassert((size_t)(image - (const uint8_t *)_image) == hdr->hdr_size);
 
     /* Compute checksum on entire header */
-    computed_chksum = H5_checksum_metadata(buf, (hdr->hdr_size - H5B2_SIZEOF_CHKSUM), 0);
+    computed_chksum = H5_checksum_metadata(_image, (hdr->hdr_size - H5B2_SIZEOF_CHKSUM), 0);
 
     /* Verify checksum */
     if(stored_chksum != computed_chksum)
@@ -242,131 +279,59 @@ H5B2__cache_hdr_load(H5F_t *f, hid_t dxpl_id, haddr_t addr, void *_udata)
         HGOTO_ERROR(H5E_BTREE, H5E_CANTINIT, NULL, "can't initialize B-tree header info")
 
     /* Set the B-tree header's address */
-    hdr->addr = addr;
+    hdr->addr = udata->addr;
+
+    /* Sanity check */
+    HDassert((size_t)(image - (const uint8_t *)_image) <= len);
 
     /* Set return value */
     ret_value = hdr;
 
 done:
-    /* Release resources */
-    if(wb && H5WB_unwrap(wb) < 0)
-        HDONE_ERROR(H5E_BTREE, H5E_CLOSEERROR, NULL, "can't close wrapped buffer")
     if(!ret_value && hdr)
         if(H5B2__hdr_free(hdr) < 0)
             HDONE_ERROR(H5E_BTREE, H5E_CANTRELEASE, NULL, "can't release v2 B-tree header")
 
     FUNC_LEAVE_NOAPI(ret_value)
-} /* end H5B2__cache_hdr_load() */ /*lint !e818 Can't make udata a pointer to const */
+} /* end H5B2__cache_hdr_deserialize() */
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5B2__cache_hdr_flush
+ * Function:    H5B2__cache_hdr_image_len
  *
- * Purpose:	Flushes a dirty B-tree header to disk.
+ * Purpose:     Compute the size of the data structure on disk.
  *
- * Return:	Non-negative on success/Negative on failure
+ * Return:      Non-negative on success/Negative on failure
  *
- * Programmer:	Quincey Koziol
- *		koziol@ncsa.uiuc.edu
- *		Feb 1 2005
+ * Programmer:  Quincey Koziol
+ *              koziol@hdfgroup.org
+ *              May 20, 2010
  *
  *-------------------------------------------------------------------------
  */
 static herr_t
-H5B2__cache_hdr_flush(H5F_t *f, hid_t dxpl_id, hbool_t destroy, haddr_t addr,
-    H5B2_hdr_t *hdr, unsigned H5_ATTR_UNUSED * flags_ptr)
+H5B2__cache_hdr_image_len(const void *_thing, size_t *image_len,
+    hbool_t H5_ATTR_UNUSED *compressed_ptr, size_t H5_ATTR_UNUSED *compressed_image_len_ptr)
 {
-    H5WB_t      *wb = NULL;             /* Wrapped buffer for header data */
-    uint8_t     hdr_buf[H5B2_HDR_BUF_SIZE]; /* Buffer for header */
-    herr_t      ret_value = SUCCEED;    /* Return value */
+    const H5B2_hdr_t *hdr = (const H5B2_hdr_t *)_thing;      /* Pointer to the B-tree header */
 
-    FUNC_ENTER_STATIC
+    FUNC_ENTER_STATIC_NOERR
 
     /* Check arguments */
-    HDassert(f);
-    HDassert(H5F_addr_defined(addr));
     HDassert(hdr);
+    HDassert(image_len);
 
-    if(hdr->cache_info.is_dirty) {
-        uint8_t	*buf;           /* Pointer to header buffer */
-        uint8_t *p;             /* Pointer into raw data buffer */
-        uint32_t metadata_chksum; /* Computed metadata checksum value */
-
-        /* Set the B-tree header's file context for this operation */
-        hdr->f = f;
-
-        /* Wrap the local buffer for serialized header info */
-        if(NULL == (wb = H5WB_wrap(hdr_buf, sizeof(hdr_buf))))
-            HGOTO_ERROR(H5E_BTREE, H5E_CANTINIT, FAIL, "can't wrap buffer")
-
-        /* Get a pointer to a buffer that's large enough for header */
-        if(NULL == (buf = (uint8_t *)H5WB_actual(wb, hdr->hdr_size)))
-            HGOTO_ERROR(H5E_BTREE, H5E_NOSPACE, FAIL, "can't get actual buffer")
-
-        /* Get temporary pointer to serialized header */
-        p = buf;
-
-        /* Magic number */
-        HDmemcpy(p, H5B2_HDR_MAGIC, (size_t)H5_SIZEOF_MAGIC);
-        p += H5_SIZEOF_MAGIC;
-
-        /* Version # */
-        *p++ = H5B2_HDR_VERSION;
-
-        /* B-tree type */
-        *p++ = hdr->cls->id;
+    /* Set the image length size */
+    *image_len = hdr->hdr_size;
 
-        /* Node size (in bytes) */
-        UINT32ENCODE(p, hdr->node_size);
-
-        /* Raw key size (in bytes) */
-        UINT16ENCODE(p, hdr->rrec_size);
-
-        /* Depth of tree */
-        UINT16ENCODE(p, hdr->depth);
-
-        /* Split & merge %s */
-        H5_CHECK_OVERFLOW(hdr->split_percent, /* From: */ unsigned, /* To: */ uint8_t);
-        *p++ = (uint8_t)hdr->split_percent;
-        H5_CHECK_OVERFLOW(hdr->merge_percent, /* From: */ unsigned, /* To: */ uint8_t);
-        *p++ = (uint8_t)hdr->merge_percent;
-
-        /* Root node pointer */
-        H5F_addr_encode(f, &p, hdr->root.addr);
-        UINT16ENCODE(p, hdr->root.node_nrec);
-        H5F_ENCODE_LENGTH(f, p, hdr->root.all_nrec);
-
-        /* Compute metadata checksum */
-        metadata_chksum = H5_checksum_metadata(buf, (hdr->hdr_size - H5B2_SIZEOF_CHKSUM), 0);
-
-        /* Metadata checksum */
-        UINT32ENCODE(p, metadata_chksum);
-
-        /* Write the B-tree header. */
-        HDassert((size_t)(p - buf) == hdr->hdr_size);
-        if(H5F_block_write(f, H5FD_MEM_BTREE, addr, hdr->hdr_size, dxpl_id, buf) < 0)
-            HGOTO_ERROR(H5E_BTREE, H5E_CANTFLUSH, FAIL, "unable to save B-tree header to disk")
-
-        hdr->cache_info.is_dirty = FALSE;
-    } /* end if */
-
-    if(destroy)
-        if(H5B2__cache_hdr_dest(f, hdr) < 0)
-            HGOTO_ERROR(H5E_BTREE, H5E_CANTFREE, FAIL, "unable to destroy B-tree header")
-
-done:
-    /* Release resources */
-    if(wb && H5WB_unwrap(wb) < 0)
-        HDONE_ERROR(H5E_BTREE, H5E_CLOSEERROR, FAIL, "can't close wrapped buffer")
-
-    FUNC_LEAVE_NOAPI(ret_value)
-} /* H5B2__cache_hdr_flush() */
+    FUNC_LEAVE_NOAPI(SUCCEED)
+} /* end H5B2__cache_hdr_image_len() */
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5B2__cache_hdr_dest
+ * Function:	H5B2__cache_hdr_serialize
  *
- * Purpose:	Destroys a B-tree header in memory.
+ * Purpose:	Flushes a dirty B-tree header to disk.
  *
  * Return:	Non-negative on success/Negative on failure
  *
@@ -377,109 +342,132 @@ done:
  *-------------------------------------------------------------------------
  */
 static herr_t
-H5B2__cache_hdr_dest(H5F_t *f, H5B2_hdr_t *hdr)
+H5B2__cache_hdr_serialize(const H5F_t *f, void *_image, size_t H5_ATTR_UNUSED len,
+    void *_thing)
 {
-    herr_t ret_value = SUCCEED;     /* Return value */
+    H5B2_hdr_t *hdr = (H5B2_hdr_t *)_thing;     /* Pointer to the B-tree header */
+    uint8_t *image = (uint8_t *)_image;         /* Pointer into raw data buffer */
+    uint32_t metadata_chksum;                   /* Computed metadata checksum value */
 
-    FUNC_ENTER_STATIC
+    FUNC_ENTER_STATIC_NOERR
 
-    /* Check arguments */
+    /* check arguments */
+    HDassert(f);
+    HDassert(image);
     HDassert(hdr);
-    HDassert(hdr->rc == 0);
 
-    /* If we're going to free the space on disk, the address must be valid */
-    HDassert(!hdr->cache_info.free_file_space_on_destroy || H5F_addr_defined(hdr->cache_info.addr));
+    /* Magic number */
+    HDmemcpy(image, H5B2_HDR_MAGIC, (size_t)H5_SIZEOF_MAGIC);
+    image += H5_SIZEOF_MAGIC;
+
+    /* Version # */
+    *image++ = H5B2_HDR_VERSION;
 
-    /* Check for freeing file space for B-tree header */
-    if(hdr->cache_info.free_file_space_on_destroy) {
-        /* Release the space on disk */
-        /* (XXX: Nasty usage of internal DXPL value! -QAK) */
-        if(H5MF_xfree(f, H5FD_MEM_BTREE, H5AC_dxpl_id, hdr->cache_info.addr, (hsize_t)hdr->hdr_size) < 0)
-            HGOTO_ERROR(H5E_BTREE, H5E_CANTFREE, FAIL, "unable to free v2 B-tree header")
-    } /* end if */
+    /* B-tree type */
+    *image++ = hdr->cls->id;
 
-    /* Release B-tree header info */
-    if(H5B2__hdr_free(hdr) < 0)
-        HGOTO_ERROR(H5E_BTREE, H5E_CANTFREE, FAIL, "unable to free v2 B-tree header info")
+    /* Node size (in bytes) */
+    UINT32ENCODE(image, hdr->node_size);
 
-done:
-    FUNC_LEAVE_NOAPI(ret_value)
-} /* end H5B2__cache_hdr_dest() */
+    /* Raw key size (in bytes) */
+    UINT16ENCODE(image, hdr->rrec_size);
+
+    /* Depth of tree */
+    UINT16ENCODE(image, hdr->depth);
+
+    /* Split & merge %s */
+    H5_CHECK_OVERFLOW(hdr->split_percent, /* From: */ unsigned, /* To: */ uint8_t);
+    *image++ = (uint8_t)hdr->split_percent;
+    H5_CHECK_OVERFLOW(hdr->merge_percent, /* From: */ unsigned, /* To: */ uint8_t);
+    *image++ = (uint8_t)hdr->merge_percent;
+
+    /* Root node pointer */
+    H5F_addr_encode(f, &image, hdr->root.addr);
+    UINT16ENCODE(image, hdr->root.node_nrec);
+    H5F_ENCODE_LENGTH(f, image, hdr->root.all_nrec);
+
+    /* Compute metadata checksum */
+    metadata_chksum = H5_checksum_metadata(_image, (hdr->hdr_size - H5B2_SIZEOF_CHKSUM), 0);
+
+    /* Metadata checksum */
+    UINT32ENCODE(image, metadata_chksum);
+
+    /* Sanity check */
+    HDassert((size_t)(image - (uint8_t *)_image) <= len);
+
+    FUNC_LEAVE_NOAPI(SUCCEED)
+} /* H5B2__cache_hdr_serialize() */
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5B2__cache_hdr_clear
+ * Function:	H5B2__cache_hdr_free_icr
  *
- * Purpose:	Mark a B-tree header in memory as non-dirty.
+ * Purpose:	Destroy/release an "in core representation" of a data
+ *              structure
  *
  * Return:	Non-negative on success/Negative on failure
  *
- * Programmer:	Quincey Koziol
- *		koziol@ncsa.uiuc.edu
- *		Feb  1 2005
+ * Programmer:	Mike McGreevy
+ *              mcgreevy@hdfgroup.org
+ *              June 18, 2008
  *
  *-------------------------------------------------------------------------
  */
 static herr_t
-H5B2__cache_hdr_clear(H5F_t *f, H5B2_hdr_t *hdr, hbool_t destroy)
+H5B2__cache_hdr_free_icr(void *thing)
 {
-    herr_t ret_value = SUCCEED;         /* Return value */
+    herr_t ret_value = SUCCEED;     /* Return value */
 
     FUNC_ENTER_STATIC
 
-    /*
-     * Check arguments.
-     */
-    HDassert(hdr);
-
-    /* Reset the dirty flag.  */
-    hdr->cache_info.is_dirty = FALSE;
+    /* Check arguments */
+    HDassert(thing);
 
-    if(destroy)
-        if(H5B2__cache_hdr_dest(f, hdr) < 0)
-	    HGOTO_ERROR(H5E_BTREE, H5E_CANTFREE, FAIL, "unable to destroy B-tree header")
+    /* Destroy v2 B-tree header */
+    if(H5B2__hdr_free((H5B2_hdr_t *)thing) < 0)
+        HGOTO_ERROR(H5E_BTREE, H5E_CANTFREE, FAIL, "unable to free v2 B-tree header")
 
 done:
     FUNC_LEAVE_NOAPI(ret_value)
-} /* end H5B2__cache_hdr_clear() */
+} /* H5B2__cache_hdr_free_icr() */
 
 
 /*-------------------------------------------------------------------------
- * Function:    H5B2__cache_hdr_size
+ * Function:    H5B2__cache_int_get_load_size
  *
- * Purpose:     Compute the size in bytes of a B-tree header
- *              on disk, and return it in *size_ptr.  On failure,
- *              the value of *size_ptr is undefined.
+ * Purpose:     Compute the size of the data structure on disk.
  *
- * Return:      SUCCEED (Can't fail)
+ * Return:      Non-negative on success/Negative on failure
  *
  * Programmer:  Quincey Koziol
  *              koziol@hdfgroup.org
- *              Feb 1 2005
+ *              May 18, 2010
  *
  *-------------------------------------------------------------------------
  */
 static herr_t
-H5B2__cache_hdr_size(const H5F_t H5_ATTR_UNUSED *f, const H5B2_hdr_t *hdr, size_t *size_ptr)
+H5B2__cache_int_get_load_size(const void *_udata, size_t *image_len)
 {
+    const H5B2_internal_cache_ud_t *udata = (const H5B2_internal_cache_ud_t *)_udata; /* User data for callback */
+
     FUNC_ENTER_STATIC_NOERR
 
     /* Check arguments */
-    HDassert(f);
-    HDassert(hdr);
-    HDassert(size_ptr);
+    HDassert(udata);
+    HDassert(udata->hdr);
+    HDassert(image_len);
 
-    /* Set size value */
-    *size_ptr = hdr->hdr_size;
+    /* Set the image length size */
+    *image_len = udata->hdr->node_size;
 
     FUNC_LEAVE_NOAPI(SUCCEED)
-} /* H5B2__cache_hdr_size() */
+} /* end H5B2__cache_int_get_load_size() */
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5B2__cache_internal_load
+ * Function:	H5B2__cache_int_deserialize
  *
- * Purpose:	Loads a B-tree internal node from the disk.
+ * Purpose:	Deserialize a B-tree internal node from the disk.
  *
  * Return:	Success:	Pointer to a new B-tree internal node.
  *              Failure:        NULL
@@ -490,12 +478,13 @@ H5B2__cache_hdr_size(const H5F_t H5_ATTR_UNUSED *f, const H5B2_hdr_t *hdr, size_
  *
  *-------------------------------------------------------------------------
  */
-static H5B2_internal_t *
-H5B2__cache_internal_load(H5F_t *f, hid_t dxpl_id, haddr_t addr, void *_udata)
+static void *
+H5B2__cache_int_deserialize(const void *_image, size_t H5_ATTR_UNUSED len,
+    void *_udata, hbool_t H5_ATTR_UNUSED *dirty)
 {
     H5B2_internal_cache_ud_t *udata = (H5B2_internal_cache_ud_t *)_udata;     /* Pointer to user data */
     H5B2_internal_t	*internal = NULL;       /* Internal node read */
-    const uint8_t	*p;             /* Pointer into raw data buffer */
+    const uint8_t	*image = (const uint8_t *)_image;       /* Pointer into raw data buffer */
     uint8_t		*native;        /* Pointer to native record info */
     H5B2_node_ptr_t	*int_node_ptr;  /* Pointer to node pointer info */
     uint32_t            stored_chksum;  /* Stored metadata checksum value */
@@ -506,8 +495,7 @@ H5B2__cache_internal_load(H5F_t *f, hid_t dxpl_id, haddr_t addr, void *_udata)
     FUNC_ENTER_STATIC
 
     /* Check arguments */
-    HDassert(f);
-    HDassert(H5F_addr_defined(addr));
+    HDassert(image);
     HDassert(udata);
 
     /* Allocate new internal node and reset cache info */
@@ -515,9 +503,6 @@ H5B2__cache_internal_load(H5F_t *f, hid_t dxpl_id, haddr_t addr, void *_udata)
 	HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, NULL, "memory allocation failed")
     HDmemset(&internal->cache_info, 0, sizeof(H5AC_info_t));
 
-    /* Set the B-tree header's file context for this operation */
-    udata->hdr->f = f;
-
     /* Increment ref. count on B-tree header */
     if(H5B2__hdr_incr(udata->hdr) < 0)
         HGOTO_ERROR(H5E_BTREE, H5E_CANTINC, NULL, "can't increment ref. count on B-tree header")
@@ -525,23 +510,17 @@ H5B2__cache_internal_load(H5F_t *f, hid_t dxpl_id, haddr_t addr, void *_udata)
     /* Share B-tree information */
     internal->hdr = udata->hdr;
 
-    /* Read header from disk */
-    if(H5F_block_read(f, H5FD_MEM_BTREE, addr, udata->hdr->node_size, dxpl_id, udata->hdr->page) < 0)
-        HGOTO_ERROR(H5E_BTREE, H5E_READERROR, NULL, "can't read B-tree internal node")
-
-    p = udata->hdr->page;
-
     /* Magic number */
-    if(HDmemcmp(p, H5B2_INT_MAGIC, (size_t)H5_SIZEOF_MAGIC))
+    if(HDmemcmp(image, H5B2_INT_MAGIC, (size_t)H5_SIZEOF_MAGIC))
         HGOTO_ERROR(H5E_BTREE, H5E_BADVALUE, NULL, "wrong B-tree internal node signature")
-    p += H5_SIZEOF_MAGIC;
+    image += H5_SIZEOF_MAGIC;
 
     /* Version */
-    if(*p++ != H5B2_INT_VERSION)
+    if(*image++ != H5B2_INT_VERSION)
 	HGOTO_ERROR(H5E_BTREE, H5E_BADRANGE, NULL, "wrong B-tree internal node version")
 
     /* B-tree type */
-    if(*p++ != (uint8_t)udata->hdr->cls->id)
+    if(*image++ != (uint8_t)udata->hdr->cls->id)
         HGOTO_ERROR(H5E_BTREE, H5E_BADTYPE, NULL, "incorrect B-tree type")
 
     /* Allocate space for the native keys in memory */
@@ -560,11 +539,11 @@ H5B2__cache_internal_load(H5F_t *f, hid_t dxpl_id, haddr_t addr, void *_udata)
     native = internal->int_native;
     for(u = 0; u < internal->nrec; u++) {
         /* Decode record */
-        if((udata->hdr->cls->decode)(p, native, udata->hdr->cb_ctx) < 0)
+        if((udata->hdr->cls->decode)(image, native, udata->hdr->cb_ctx) < 0)
             HGOTO_ERROR(H5E_BTREE, H5E_CANTDECODE, NULL, "unable to decode B-tree record")
 
         /* Move to next record */
-        p += udata->hdr->rrec_size;
+        image += udata->hdr->rrec_size;
         native += udata->hdr->cls->nrec_size;
     } /* end for */
 
@@ -572,10 +551,10 @@ H5B2__cache_internal_load(H5F_t *f, hid_t dxpl_id, haddr_t addr, void *_udata)
     int_node_ptr = internal->node_ptrs;
     for(u = 0; u < (unsigned)(internal->nrec + 1); u++) {
         /* Decode node pointer */
-        H5F_addr_decode(udata->f, (const uint8_t **)&p, &(int_node_ptr->addr));
-        UINT64DECODE_VAR(p, int_node_ptr->node_nrec, udata->hdr->max_nrec_size);
+        H5F_addr_decode(udata->f, (const uint8_t **)&image, &(int_node_ptr->addr));
+        UINT64DECODE_VAR(image, int_node_ptr->node_nrec, udata->hdr->max_nrec_size);
         if(udata->depth > 1)
-            UINT64DECODE_VAR(p, int_node_ptr->all_nrec, udata->hdr->node_info[udata->depth - 1].cum_max_nrec_size)
+            UINT64DECODE_VAR(image, int_node_ptr->all_nrec, udata->hdr->node_info[udata->depth - 1].cum_max_nrec_size)
         else
             int_node_ptr->all_nrec = int_node_ptr->node_nrec;
 
@@ -584,13 +563,13 @@ H5B2__cache_internal_load(H5F_t *f, hid_t dxpl_id, haddr_t addr, void *_udata)
     } /* end for */
 
     /* Compute checksum on internal node */
-    computed_chksum = H5_checksum_metadata(udata->hdr->page, (size_t)(p - (const uint8_t *)udata->hdr->page), 0);
+    computed_chksum = H5_checksum_metadata(_image, (size_t)(image - (const uint8_t *)_image), 0);
 
     /* Metadata checksum */
-    UINT32DECODE(p, stored_chksum);
+    UINT32DECODE(image, stored_chksum);
 
     /* Sanity check parsing */
-    HDassert((size_t)(p - (const uint8_t *)udata->hdr->page) <= udata->hdr->node_size);
+    HDassert((size_t)(image - (const uint8_t *)_image) <= len);
 
     /* Verify checksum */
     if(stored_chksum != computed_chksum)
@@ -605,224 +584,194 @@ done:
             HDONE_ERROR(H5E_BTREE, H5E_CANTFREE, NULL, "unable to destroy B-tree internal node")
 
     FUNC_LEAVE_NOAPI(ret_value)
-} /* H5B2__cache_internal_load() */ /*lint !e818 Can't make udata a pointer to const */
+} /* H5B2__cache_int_deserialize() */
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5B2__cache_internal_flush
+ * Function:    H5B2__cache_int_image_len
  *
- * Purpose:	Flushes a dirty B-tree internal node to disk.
+ * Purpose:     Compute the size of the data structure on disk.
  *
- * Return:	Non-negative on success/Negative on failure
+ * Return:      Non-negative on success/Negative on failure
  *
- * Programmer:	Quincey Koziol
- *		koziol@ncsa.uiuc.edu
- *		Feb 3 2005
+ * Programmer:  Quincey Koziol
+ *              koziol@hdfgroup.org
+ *              May 20, 2010
  *
  *-------------------------------------------------------------------------
  */
 static herr_t
-H5B2__cache_internal_flush(H5F_t *f, hid_t dxpl_id, hbool_t destroy, haddr_t addr, H5B2_internal_t *internal, unsigned H5_ATTR_UNUSED * flags_ptr)
+H5B2__cache_int_image_len(const void *_thing, size_t *image_len,
+    hbool_t H5_ATTR_UNUSED *compressed_ptr, size_t H5_ATTR_UNUSED *compressed_image_len_ptr)
 {
-    herr_t      ret_value = SUCCEED;    /* Return value */
+    const H5B2_internal_t *internal = (const H5B2_internal_t *)_thing;      /* Pointer to the B-tree internal node */
 
-    FUNC_ENTER_STATIC
+    FUNC_ENTER_STATIC_NOERR
 
     /* Check arguments */
-    HDassert(f);
-    HDassert(H5F_addr_defined(addr));
     HDassert(internal);
     HDassert(internal->hdr);
+    HDassert(image_len);
 
-    if(internal->cache_info.is_dirty) {
-        uint8_t *p;             /* Pointer into raw data buffer */
-        uint8_t *native;        /* Pointer to native record info */
-        H5B2_node_ptr_t *int_node_ptr;      /* Pointer to node pointer info */
-        uint32_t metadata_chksum; /* Computed metadata checksum value */
-        unsigned u;             /* Local index variable */
-
-        /* Set the B-tree header's file context for this operation */
-        internal->hdr->f = f;
-
-        p = internal->hdr->page;
-
-        /* Magic number */
-        HDmemcpy(p, H5B2_INT_MAGIC, (size_t)H5_SIZEOF_MAGIC);
-        p += H5_SIZEOF_MAGIC;
-
-        /* Version # */
-        *p++ = H5B2_INT_VERSION;
-
-        /* B-tree type */
-        *p++ = internal->hdr->cls->id;
-        HDassert((size_t)(p - internal->hdr->page) == (H5B2_INT_PREFIX_SIZE - H5B2_SIZEOF_CHKSUM));
-
-        /* Serialize records for internal node */
-        native = internal->int_native;
-        for(u = 0; u < internal->nrec; u++) {
-            /* Encode record */
-            if((internal->hdr->cls->encode)(p, native, internal->hdr->cb_ctx) < 0)
-                HGOTO_ERROR(H5E_BTREE, H5E_CANTENCODE, FAIL, "unable to encode B-tree record")
-
-            /* Move to next record */
-            p += internal->hdr->rrec_size;
-            native += internal->hdr->cls->nrec_size;
-        } /* end for */
-
-        /* Serialize node pointers for internal node */
-        int_node_ptr = internal->node_ptrs;
-        for(u = 0; u < (unsigned)(internal->nrec + 1); u++) {
-            /* Encode node pointer */
-            H5F_addr_encode(f, &p, int_node_ptr->addr);
-            UINT64ENCODE_VAR(p, int_node_ptr->node_nrec, internal->hdr->max_nrec_size);
-            if(internal->depth > 1)
-                UINT64ENCODE_VAR(p, int_node_ptr->all_nrec, internal->hdr->node_info[internal->depth - 1].cum_max_nrec_size);
-
-            /* Move to next node pointer */
-            int_node_ptr++;
-        } /* end for */
-
-        /* Compute metadata checksum */
-        metadata_chksum = H5_checksum_metadata(internal->hdr->page, (size_t)(p - internal->hdr->page), 0);
-
-        /* Metadata checksum */
-        UINT32ENCODE(p, metadata_chksum);
-
-	/* Write the B-tree internal node */
-        HDassert((size_t)(p - internal->hdr->page) <= internal->hdr->node_size);
-	if(H5F_block_write(f, H5FD_MEM_BTREE, addr, internal->hdr->node_size, dxpl_id, internal->hdr->page) < 0)
-	    HGOTO_ERROR(H5E_BTREE, H5E_CANTFLUSH, FAIL, "unable to save B-tree internal node to disk")
+    /* Set the image length size */
+    *image_len = internal->hdr->node_size;
 
-	internal->cache_info.is_dirty = FALSE;
-    } /* end if */
-
-    if(destroy)
-        if(H5B2__cache_internal_dest(f, internal) < 0)
-	    HGOTO_ERROR(H5E_BTREE, H5E_CANTFREE, FAIL, "unable to destroy B-tree internal node")
-
-done:
-    FUNC_LEAVE_NOAPI(ret_value)
-} /* H5B2__cache_internal_flush() */
+    FUNC_LEAVE_NOAPI(SUCCEED)
+} /* end H5B2__cache_int_image_len() */
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5B2__cache_internal_dest
+ * Function:	H5B2__cache_int_serialize
  *
- * Purpose:	Destroys a B-tree internal node in memory.
+ * Purpose:	Serializes a B-tree internal node for writing to disk.
  *
  * Return:	Non-negative on success/Negative on failure
  *
  * Programmer:	Quincey Koziol
  *		koziol@ncsa.uiuc.edu
- *		Feb 2 2005
+ *		Feb 3 2005
  *
  *-------------------------------------------------------------------------
  */
 static herr_t
-H5B2__cache_internal_dest(H5F_t *f, H5B2_internal_t *internal)
+H5B2__cache_int_serialize(const H5F_t *f, void *_image, size_t H5_ATTR_UNUSED len,
+    void *_thing)
 {
-    herr_t ret_value = SUCCEED;     /* Return value */
+    H5B2_internal_t *internal = (H5B2_internal_t *)_thing;      /* Pointer to the B-tree internal node */
+    uint8_t *image = (uint8_t *)_image; /* Pointer into raw data buffer */
+    uint8_t *native;        /* Pointer to native record info */
+    H5B2_node_ptr_t *int_node_ptr;      /* Pointer to node pointer info */
+    uint32_t metadata_chksum; /* Computed metadata checksum value */
+    unsigned u;             /* Local index variable */
+    herr_t      ret_value = SUCCEED;    /* Return value */
 
     FUNC_ENTER_STATIC
 
-    /* Check arguments */
+    /* check arguments */
     HDassert(f);
+    HDassert(image);
     HDassert(internal);
     HDassert(internal->hdr);
 
-    /* If we're going to free the space on disk, the address must be valid */
-    HDassert(!internal->cache_info.free_file_space_on_destroy || H5F_addr_defined(internal->cache_info.addr));
+    /* Magic number */
+    HDmemcpy(image, H5B2_INT_MAGIC, (size_t)H5_SIZEOF_MAGIC);
+    image += H5_SIZEOF_MAGIC;
+
+    /* Version # */
+    *image++ = H5B2_INT_VERSION;
 
-    /* Check for freeing file space for B-tree internal node */
-    if(internal->cache_info.free_file_space_on_destroy) {
-        /* Release the space on disk */
-        /* (XXX: Nasty usage of internal DXPL value! -QAK) */
-        if(H5MF_xfree(f, H5FD_MEM_BTREE, H5AC_dxpl_id, internal->cache_info.addr, (hsize_t)internal->hdr->node_size) < 0)
-            HGOTO_ERROR(H5E_BTREE, H5E_CANTFREE, FAIL, "unable to free v2 B-tree internal node")
-    } /* end if */
+    /* B-tree type */
+    *image++ = internal->hdr->cls->id;
+    HDassert((size_t)(image - (uint8_t *)_image) == (H5B2_INT_PREFIX_SIZE - H5B2_SIZEOF_CHKSUM));
 
-    /* Release v2 b-tree internal node */
-    if(H5B2__internal_free(internal) < 0)
-        HGOTO_ERROR(H5E_BTREE, H5E_CANTFREE, FAIL, "unable to release v2 B-tree internal node")
+    /* Serialize records for internal node */
+    native = internal->int_native;
+    for(u = 0; u < internal->nrec; u++) {
+        /* Encode record */
+        if((internal->hdr->cls->encode)(image, native, internal->hdr->cb_ctx) < 0)
+            HGOTO_ERROR(H5E_BTREE, H5E_CANTENCODE, FAIL, "unable to encode B-tree record")
+
+        /* Move to next record */
+        image += internal->hdr->rrec_size;
+        native += internal->hdr->cls->nrec_size;
+    } /* end for */
+
+    /* Serialize node pointers for internal node */
+    int_node_ptr = internal->node_ptrs;
+    for(u = 0; u < (unsigned)(internal->nrec + 1); u++) {
+        /* Encode node pointer */
+        H5F_addr_encode(f, &image, int_node_ptr->addr);
+        UINT64ENCODE_VAR(image, int_node_ptr->node_nrec, internal->hdr->max_nrec_size);
+        if(internal->depth > 1)
+            UINT64ENCODE_VAR(image, int_node_ptr->all_nrec, internal->hdr->node_info[internal->depth - 1].cum_max_nrec_size);
+
+        /* Move to next node pointer */
+        int_node_ptr++;
+    } /* end for */
+
+    /* Compute metadata checksum */
+    metadata_chksum = H5_checksum_metadata(_image, (size_t)(image - (uint8_t *)_image), 0);
+
+    /* Metadata checksum */
+    UINT32ENCODE(image, metadata_chksum);
+
+    /* Sanity check */
+    HDassert((size_t)(image - (uint8_t *)_image) <= len);
 
 done:
     FUNC_LEAVE_NOAPI(ret_value)
-} /* end H5B2__cache_internal_dest() */
+} /* H5B2__cache_int_serialize() */
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5B2__cache_internal_clear
+ * Function:	H5B2__cache_int_free_icr
  *
- * Purpose:	Mark a B-tree internal node in memory as non-dirty.
+ * Purpose:	Destroy/release an "in core representation" of a data
+ *              structure
  *
  * Return:	Non-negative on success/Negative on failure
  *
- * Programmer:	Quincey Koziol
- *		koziol@ncsa.uiuc.edu
- *		Feb  2 2005
+ * Programmer:	Mike McGreevy
+ *              mcgreevy@hdfgroup.org
+ *              June 18, 2008
  *
  *-------------------------------------------------------------------------
  */
 static herr_t
-H5B2__cache_internal_clear(H5F_t *f, H5B2_internal_t *internal, hbool_t destroy)
+H5B2__cache_int_free_icr(void *thing)
 {
-    herr_t ret_value = SUCCEED;
+    herr_t ret_value = SUCCEED;     /* Return value */
 
     FUNC_ENTER_STATIC
 
-    /*
-     * Check arguments.
-     */
-    HDassert(internal);
-
-    /* Reset the dirty flag.  */
-    internal->cache_info.is_dirty = FALSE;
+    /* Check arguments */
+    HDassert(thing);
 
-    if(destroy)
-        if(H5B2__cache_internal_dest(f, internal) < 0)
-	    HGOTO_ERROR(H5E_BTREE, H5E_CANTFREE, FAIL, "unable to destroy B-tree internal node")
+    /* Release v2 B-tree internal node */
+    if(H5B2__internal_free((H5B2_internal_t *)thing) < 0)
+        HGOTO_ERROR(H5E_BTREE, H5E_CANTFREE, FAIL, "unable to release v2 B-tree internal node")
 
 done:
     FUNC_LEAVE_NOAPI(ret_value)
-} /* end H5B2__cache_internal_clear() */
+} /* H5B2__cache_int_free_icr() */
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5B2__cache_internal_size
+ * Function:    H5B2__cache_leaf_get_load_size
  *
- * Purpose:	Compute the size in bytes of a B-tree internal node
- *		on disk, and return it in *size_ptr.  On failure,
- *		the value of *size_ptr is undefined.
+ * Purpose:     Compute the size of the data structure on disk.
  *
- * Return:	Non-negative on success/Negative on failure
+ * Return:      Non-negative on success/Negative on failure
  *
- * Programmer:	Quincey Koziol
- *		koziol@ncsa.uiuc.edu
- *		Feb 2 2005
+ * Programmer:  Quincey Koziol
+ *              koziol@hdfgroup.org
+ *              May 18, 2010
  *
  *-------------------------------------------------------------------------
  */
 static herr_t
-H5B2__cache_internal_size(const H5F_t H5_ATTR_UNUSED *f, const H5B2_internal_t *internal, size_t *size_ptr)
+H5B2__cache_leaf_get_load_size(const void *_udata, size_t *image_len)
 {
+    const H5B2_leaf_cache_ud_t *udata = (const H5B2_leaf_cache_ud_t *)_udata; /* User data for callback */
+
     FUNC_ENTER_STATIC_NOERR
 
     /* Check arguments */
-    HDassert(internal);
-    HDassert(internal->hdr);
-    HDassert(size_ptr);
+    HDassert(udata);
+    HDassert(udata->hdr);
+    HDassert(image_len);
 
-    /* Set size value */
-    *size_ptr = internal->hdr->node_size;
+    /* Set the image length size */
+    *image_len = udata->hdr->node_size;
 
     FUNC_LEAVE_NOAPI(SUCCEED)
-} /* H5B2__cache_internal_size() */
+} /* end H5B2__cache_leaf_get_load_size() */
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5B2__cache_leaf_load
+ * Function:	H5B2__cache_leaf_deserialize
  *
- * Purpose:	Loads a B-tree leaf from the disk.
+ * Purpose:	Deserialize a B-tree leaf from the disk.
  *
  * Return:	Success:	Pointer to a new B-tree leaf node.
  *		Failure:	NULL
@@ -833,12 +782,13 @@ H5B2__cache_internal_size(const H5F_t H5_ATTR_UNUSED *f, const H5B2_internal_t *
  *
  *-------------------------------------------------------------------------
  */
-static H5B2_leaf_t *
-H5B2__cache_leaf_load(H5F_t H5_ATTR_UNUSED *f, hid_t dxpl_id, haddr_t addr, void *_udata)
+static void *
+H5B2__cache_leaf_deserialize(const void *_image, size_t H5_ATTR_UNUSED len,
+    void *_udata, hbool_t H5_ATTR_UNUSED *dirty)
 {
     H5B2_leaf_cache_ud_t *udata = (H5B2_leaf_cache_ud_t *)_udata;
     H5B2_leaf_t		*leaf = NULL;   /* Pointer to lead node loaded */
-    const uint8_t	*p;             /* Pointer into raw data buffer */
+    const uint8_t	*image = (const uint8_t *)_image;       /* Pointer into raw data buffer */
     uint8_t		*native;        /* Pointer to native keys */
     uint32_t            stored_chksum;  /* Stored metadata checksum value */
     uint32_t            computed_chksum; /* Computed metadata checksum value */
@@ -848,8 +798,7 @@ H5B2__cache_leaf_load(H5F_t H5_ATTR_UNUSED *f, hid_t dxpl_id, haddr_t addr, void
     FUNC_ENTER_STATIC
 
     /* Check arguments */
-    HDassert(f);
-    HDassert(H5F_addr_defined(addr));
+    HDassert(image);
     HDassert(udata);
 
     /* Allocate new leaf node and reset cache info */
@@ -857,9 +806,6 @@ H5B2__cache_leaf_load(H5F_t H5_ATTR_UNUSED *f, hid_t dxpl_id, haddr_t addr, void
 	HGOTO_ERROR(H5E_BTREE, H5E_CANTALLOC, NULL, "memory allocation failed")
     HDmemset(&leaf->cache_info, 0, sizeof(H5AC_info_t));
 
-    /* Set the B-tree header's file context for this operation */
-    udata->hdr->f = udata->f;
-
     /* Increment ref. count on B-tree header */
     if(H5B2__hdr_incr(udata->hdr) < 0)
         HGOTO_ERROR(H5E_BTREE, H5E_CANTINC, NULL, "can't increment ref. count on B-tree header")
@@ -867,23 +813,17 @@ H5B2__cache_leaf_load(H5F_t H5_ATTR_UNUSED *f, hid_t dxpl_id, haddr_t addr, void
     /* Share B-tree header information */
     leaf->hdr = udata->hdr;
 
-    /* Read header from disk */
-    if(H5F_block_read(udata->f, H5FD_MEM_BTREE, addr, udata->hdr->node_size, dxpl_id, udata->hdr->page) < 0)
-        HGOTO_ERROR(H5E_BTREE, H5E_READERROR, NULL, "can't read B-tree leaf node")
-
-    p = udata->hdr->page;
-
     /* Magic number */
-    if(HDmemcmp(p, H5B2_LEAF_MAGIC, (size_t)H5_SIZEOF_MAGIC))
+    if(HDmemcmp(image, H5B2_LEAF_MAGIC, (size_t)H5_SIZEOF_MAGIC))
 	HGOTO_ERROR(H5E_BTREE, H5E_BADVALUE, NULL, "wrong B-tree leaf node signature")
-    p += H5_SIZEOF_MAGIC;
+    image += H5_SIZEOF_MAGIC;
 
     /* Version */
-    if(*p++ != H5B2_LEAF_VERSION)
+    if(*image++ != H5B2_LEAF_VERSION)
 	HGOTO_ERROR(H5E_BTREE, H5E_BADRANGE, NULL, "wrong B-tree leaf node version")
 
     /* B-tree type */
-    if(*p++ != (uint8_t)udata->hdr->cls->id)
+    if(*image++ != (uint8_t)udata->hdr->cls->id)
         HGOTO_ERROR(H5E_BTREE, H5E_BADTYPE, NULL, "incorrect B-tree type")
 
     /* Allocate space for the native keys in memory */
@@ -897,27 +837,30 @@ H5B2__cache_leaf_load(H5F_t H5_ATTR_UNUSED *f, hid_t dxpl_id, haddr_t addr, void
     native = leaf->leaf_native;
     for(u = 0; u < leaf->nrec; u++) {
         /* Decode record */
-        if((udata->hdr->cls->decode)(p, native, udata->hdr->cb_ctx) < 0)
+        if((udata->hdr->cls->decode)(image, native, udata->hdr->cb_ctx) < 0)
             HGOTO_ERROR(H5E_BTREE, H5E_CANTENCODE, NULL, "unable to decode B-tree record")
 
         /* Move to next record */
-        p += udata->hdr->rrec_size;
+        image += udata->hdr->rrec_size;
         native += udata->hdr->cls->nrec_size;
     } /* end for */
 
     /* Compute checksum on leaf node */
-    computed_chksum = H5_checksum_metadata(udata->hdr->page, (size_t)(p - (const uint8_t *)udata->hdr->page), 0);
+    computed_chksum = H5_checksum_metadata(_image, (size_t)(image - (const uint8_t *)_image), 0);
 
     /* Metadata checksum */
-    UINT32DECODE(p, stored_chksum);
+    UINT32DECODE(image, stored_chksum);
 
     /* Sanity check parsing */
-    HDassert((size_t)(p - (const uint8_t *)udata->hdr->page) <= udata->hdr->node_size);
+    HDassert((size_t)(image - (const uint8_t *)_image) <= udata->hdr->node_size);
 
     /* Verify checksum */
     if(stored_chksum != computed_chksum)
 	HGOTO_ERROR(H5E_BTREE, H5E_BADVALUE, NULL, "incorrect metadata checksum for v2 leaf node")
 
+    /* Sanity check */
+    HDassert((size_t)(image - (const uint8_t *)_image) <= len);
+
     /* Set return value */
     ret_value = leaf;
 
@@ -927,96 +870,46 @@ done:
             HDONE_ERROR(H5E_BTREE, H5E_CANTFREE, NULL, "unable to destroy B-tree leaf node")
 
     FUNC_LEAVE_NOAPI(ret_value)
-} /* H5B2__cache_leaf_load() */ /*lint !e818 Can't make udata a pointer to const */
+} /* H5B2__cache_leaf_deserialize() */
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5B2__cache_leaf_flush
+ * Function:    H5B2__cache_leaf_image_len
  *
- * Purpose:	Flushes a dirty B-tree leaf node to disk.
+ * Purpose:     Compute the size of the data structure on disk.
  *
- * Return:	Non-negative on success/Negative on failure
+ * Return:      Non-negative on success/Negative on failure
  *
- * Programmer:	Quincey Koziol
- *		koziol@ncsa.uiuc.edu
- *		Feb 2 2005
+ * Programmer:  Quincey Koziol
+ *              koziol@hdfgroup.org
+ *              May 20, 2010
  *
  *-------------------------------------------------------------------------
  */
 static herr_t
-H5B2__cache_leaf_flush(H5F_t *f, hid_t dxpl_id, hbool_t destroy, haddr_t addr, H5B2_leaf_t *leaf, unsigned H5_ATTR_UNUSED * flags_ptr)
+H5B2__cache_leaf_image_len(const void *_thing, size_t *image_len,
+    hbool_t H5_ATTR_UNUSED *compressed_ptr, size_t H5_ATTR_UNUSED *compressed_image_len_ptr)
 {
-    herr_t      ret_value = SUCCEED;    /* Return value */
+    const H5B2_leaf_t *leaf = (const H5B2_leaf_t *)_thing;      /* Pointer to the B-tree leaf node  */
 
-    FUNC_ENTER_STATIC
+    FUNC_ENTER_STATIC_NOERR
 
     /* Check arguments */
-    HDassert(f);
-    HDassert(H5F_addr_defined(addr));
     HDassert(leaf);
     HDassert(leaf->hdr);
+    HDassert(image_len);
 
-    if(leaf->cache_info.is_dirty) {
-        uint8_t *p;             /* Pointer into raw data buffer */
-        uint8_t *native;        /* Pointer to native keys */
-        uint32_t metadata_chksum; /* Computed metadata checksum value */
-        unsigned u;             /* Local index variable */
-
-        /* Set the B-tree header's file context for this operation */
-        leaf->hdr->f = f;
-
-        p = leaf->hdr->page;
-
-        /* magic number */
-        HDmemcpy(p, H5B2_LEAF_MAGIC, (size_t)H5_SIZEOF_MAGIC);
-        p += H5_SIZEOF_MAGIC;
-
-        /* version # */
-        *p++ = H5B2_LEAF_VERSION;
-
-        /* b-tree type */
-        *p++ = leaf->hdr->cls->id;
-        HDassert((size_t)(p - leaf->hdr->page) == (H5B2_LEAF_PREFIX_SIZE - H5B2_SIZEOF_CHKSUM));
+    /* Set the image length size */
+    *image_len = leaf->hdr->node_size;
 
-        /* Serialize records for leaf node */
-        native = leaf->leaf_native;
-        for(u = 0; u < leaf->nrec; u++) {
-            /* Encode record */
-            if((leaf->hdr->cls->encode)(p, native, leaf->hdr->cb_ctx) < 0)
-                HGOTO_ERROR(H5E_BTREE, H5E_CANTENCODE, FAIL, "unable to encode B-tree record")
-
-            /* Move to next record */
-            p += leaf->hdr->rrec_size;
-            native += leaf->hdr->cls->nrec_size;
-        } /* end for */
-
-        /* Compute metadata checksum */
-        metadata_chksum = H5_checksum_metadata(leaf->hdr->page, (size_t)(p - leaf->hdr->page), 0);
-
-        /* Metadata checksum */
-        UINT32ENCODE(p, metadata_chksum);
-
-	/* Write the B-tree leaf node */
-        HDassert((size_t)(p - leaf->hdr->page) <= leaf->hdr->node_size);
-	if(H5F_block_write(f, H5FD_MEM_BTREE, addr, leaf->hdr->node_size, dxpl_id, leaf->hdr->page) < 0)
-	    HGOTO_ERROR(H5E_BTREE, H5E_CANTFLUSH, FAIL, "unable to save B-tree leaf node to disk")
-
-	leaf->cache_info.is_dirty = FALSE;
-    } /* end if */
-
-    if(destroy)
-        if(H5B2__cache_leaf_dest(f, leaf) < 0)
-	    HGOTO_ERROR(H5E_BTREE, H5E_CANTFREE, FAIL, "unable to destroy B-tree leaf node")
-
-done:
-    FUNC_LEAVE_NOAPI(ret_value)
-} /* H5B2__cache_leaf_flush() */
+    FUNC_LEAVE_NOAPI(SUCCEED)
+} /* end H5B2__cache_leaf_image_len() */
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5B2__cache_leaf_dest
+ * Function:	H5B2__cache_leaf_serialize
  *
- * Purpose:	Destroys a B-tree leaf node in memory.
+ * Purpose:	Serializes a B-tree leaf node for writing to disk.
  *
  * Return:	Non-negative on success/Negative on failure
  *
@@ -1027,102 +920,90 @@ done:
  *-------------------------------------------------------------------------
  */
 static herr_t
-H5B2__cache_leaf_dest(H5F_t *f, H5B2_leaf_t *leaf)
+H5B2__cache_leaf_serialize(const H5F_t *f, void *_image, size_t H5_ATTR_UNUSED len,
+    void *_thing)
 {
-    herr_t ret_value = SUCCEED;     /* Return value */
+    H5B2_leaf_t *leaf = (H5B2_leaf_t *)_thing;      /* Pointer to the B-tree leaf node  */
+    uint8_t *image = (uint8_t *)_image;         /* Pointer into raw data buffer */
+    uint8_t *native;            /* Pointer to native keys */
+    uint32_t metadata_chksum;   /* Computed metadata checksum value */
+    unsigned u;                 /* Local index variable */
+    herr_t ret_value = SUCCEED; /* Return value */
 
     FUNC_ENTER_STATIC
 
-    /* Check arguments */
+    /* check arguments */
     HDassert(f);
+    HDassert(image);
     HDassert(leaf);
     HDassert(leaf->hdr);
 
-    /* If we're going to free the space on disk, the address must be valid */
-    HDassert(!leaf->cache_info.free_file_space_on_destroy || H5F_addr_defined(leaf->cache_info.addr));
-
-    /* Check for freeing file space for B-tree leaf node */
-    if(leaf->cache_info.free_file_space_on_destroy) {
-        /* Release the space on disk */
-        /* (XXX: Nasty usage of internal DXPL value! -QAK) */
-        if(H5MF_xfree(f, H5FD_MEM_BTREE, H5AC_dxpl_id, leaf->cache_info.addr, (hsize_t)leaf->hdr->node_size) < 0)
-            HGOTO_ERROR(H5E_BTREE, H5E_CANTFREE, FAIL, "unable to free v2 B-tree leaf node")
-    } /* end if */
+    /* magic number */
+    HDmemcpy(image, H5B2_LEAF_MAGIC, (size_t)H5_SIZEOF_MAGIC);
+    image += H5_SIZEOF_MAGIC;
 
-    /* Destroy v2 b-tree leaf node */
-    if(H5B2__leaf_free(leaf) < 0)
-        HGOTO_ERROR(H5E_BTREE, H5E_CANTFREE, FAIL, "unable to destroy B-tree leaf node")
+    /* version # */
+    *image++ = H5B2_LEAF_VERSION;
 
-done:
-    FUNC_LEAVE_NOAPI(ret_value)
-} /* end H5B2__cache_leaf_dest() */
+    /* B-tree type */
+    *image++ = leaf->hdr->cls->id;
+    HDassert((size_t)(image - (uint8_t *)_image) == (H5B2_LEAF_PREFIX_SIZE - H5B2_SIZEOF_CHKSUM));
 
-
-/*-------------------------------------------------------------------------
- * Function:	H5B2__cache_leaf_clear
- *
- * Purpose:	Mark a B-tree leaf node in memory as non-dirty.
- *
- * Return:	Non-negative on success/Negative on failure
- *
- * Programmer:	Quincey Koziol
- *		koziol@ncsa.uiuc.edu
- *		Feb  2 2005
- *
- *-------------------------------------------------------------------------
- */
-static herr_t
-H5B2__cache_leaf_clear(H5F_t *f, H5B2_leaf_t *leaf, hbool_t destroy)
-{
-    herr_t ret_value = SUCCEED;
+    /* Serialize records for leaf node */
+    native = leaf->leaf_native;
+    for(u = 0; u < leaf->nrec; u++) {
+        /* Encode record */
+        if((leaf->hdr->cls->encode)(image, native, leaf->hdr->cb_ctx) < 0)
+            HGOTO_ERROR(H5E_BTREE, H5E_CANTENCODE, FAIL, "unable to encode B-tree record")
 
-    FUNC_ENTER_STATIC
+        /* Move to next record */
+        image += leaf->hdr->rrec_size;
+        native += leaf->hdr->cls->nrec_size;
+    } /* end for */
 
-    /*
-     * Check arguments.
-     */
-    HDassert(leaf);
+    /* Compute metadata checksum */
+    metadata_chksum = H5_checksum_metadata(_image, (size_t)((const uint8_t *)image - (const uint8_t *)_image), 0);
 
-    /* Reset the dirty flag.  */
-    leaf->cache_info.is_dirty = FALSE;
+    /* Metadata checksum */
+    UINT32ENCODE(image, metadata_chksum);
 
-    if(destroy)
-        if(H5B2__cache_leaf_dest(f, leaf) < 0)
-	    HGOTO_ERROR(H5E_BTREE, H5E_CANTFREE, FAIL, "unable to destroy B-tree leaf node")
+    /* Sanity check */
+    HDassert((size_t)(image - (uint8_t *)_image) <= len);
 
 done:
     FUNC_LEAVE_NOAPI(ret_value)
-} /* end H5B2__cache_leaf_clear() */
+} /* H5B2__cache_leaf_serialize() */
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5B2__cache_leaf_size
+ * Function:	H5B2__cache_leaf_free_icr
  *
- * Purpose:	Compute the size in bytes of a B-tree leaf node
- *		on disk, and return it in *size_ptr.  On failure,
- *		the value of *size_ptr is undefined.
+ * Purpose:	Destroy/release an "in core representation" of a data
+ *              structure
  *
  * Return:	Non-negative on success/Negative on failure
  *
- * Programmer:	Quincey Koziol
- *		koziol@ncsa.uiuc.edu
- *		Feb 2 2005
+ * Programmer:	Mike McGreevy
+ *              mcgreevy@hdfgroup.org
+ *              June 18, 2008
  *
  *-------------------------------------------------------------------------
  */
 static herr_t
-H5B2__cache_leaf_size(const H5F_t H5_ATTR_UNUSED *f, const H5B2_leaf_t *leaf, size_t *size_ptr)
+H5B2__cache_leaf_free_icr(void *thing)
 {
-    FUNC_ENTER_STATIC_NOERR
+    herr_t ret_value = SUCCEED;     /* Return value */
 
-    /* check arguments */
-    HDassert(leaf);
-    HDassert(leaf->hdr);
-    HDassert(size_ptr);
+    FUNC_ENTER_STATIC
 
-    /* Set size value */
-    *size_ptr = leaf->hdr->node_size;
+    /* Check arguments */
+    HDassert(thing);
 
-    FUNC_LEAVE_NOAPI(SUCCEED)
-} /* H5B2__cache_leaf_size() */
+    /* Destroy v2 B-tree leaf node */
+    if(H5B2__leaf_free((H5B2_leaf_t *)thing) < 0)
+        HGOTO_ERROR(H5E_BTREE, H5E_CANTFREE, FAIL, "unable to destroy B-tree leaf node")
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* H5B2__cache_leaf_free_icr() */
 
diff --git a/src/H5B2dbg.c b/src/H5B2dbg.c
index 50283f8..6e1250b 100644
--- a/src/H5B2dbg.c
+++ b/src/H5B2dbg.c
@@ -123,8 +123,9 @@ H5B2__hdr_debug(H5F_t *f, hid_t dxpl_id, haddr_t addr, FILE *stream, int indent,
      * Load the B-tree header.
      */
     cache_udata.f = f;
+    cache_udata.addr = addr;
     cache_udata.ctx_udata = dbg_ctx;
-    if(NULL == (hdr = (H5B2_hdr_t *)H5AC_protect(f, dxpl_id, H5AC_BT2_HDR, addr, &cache_udata, H5AC_READ)))
+    if(NULL == (hdr = (H5B2_hdr_t *)H5AC_protect(f, dxpl_id, H5AC_BT2_HDR, addr, &cache_udata, H5AC__READ_ONLY_FLAG)))
 	HGOTO_ERROR(H5E_BTREE, H5E_CANTLOAD, FAIL, "unable to load B-tree header")
 
     /* Set file pointer for this B-tree operation */
@@ -241,8 +242,9 @@ H5B2__int_debug(H5F_t *f, hid_t dxpl_id, haddr_t addr, FILE *stream, int indent,
      * Load the B-tree header.
      */
     cache_udata.f = f;
+    cache_udata.addr = hdr_addr;
     cache_udata.ctx_udata = dbg_ctx;
-    if(NULL == (hdr = (H5B2_hdr_t *)H5AC_protect(f, dxpl_id, H5AC_BT2_HDR, hdr_addr, &cache_udata, H5AC_READ)))
+    if(NULL == (hdr = (H5B2_hdr_t *)H5AC_protect(f, dxpl_id, H5AC_BT2_HDR, hdr_addr, &cache_udata, H5AC__READ_ONLY_FLAG)))
 	HGOTO_ERROR(H5E_BTREE, H5E_CANTLOAD, FAIL, "unable to load B-tree header")
 
     /* Set file pointer for this B-tree operation */
@@ -253,7 +255,7 @@ H5B2__int_debug(H5F_t *f, hid_t dxpl_id, haddr_t addr, FILE *stream, int indent,
      */
     H5_CHECK_OVERFLOW(nrec, unsigned, uint16_t);
     H5_CHECK_OVERFLOW(depth, unsigned, uint16_t);
-    if(NULL == (internal = H5B2__protect_internal(hdr, dxpl_id, addr, (uint16_t)nrec, (uint16_t)depth, H5AC_READ)))
+    if(NULL == (internal = H5B2__protect_internal(hdr, dxpl_id, addr, (uint16_t)nrec, (uint16_t)depth, H5AC__READ_ONLY_FLAG)))
 	HGOTO_ERROR(H5E_BTREE, H5E_CANTLOAD, FAIL, "unable to load B-tree internal node")
 
     /* Print opening message */
@@ -375,8 +377,9 @@ H5B2__leaf_debug(H5F_t *f, hid_t dxpl_id, haddr_t addr, FILE *stream, int indent
      * Load the B-tree header.
      */
     cache_udata.f = f;
+    cache_udata.addr = hdr_addr;
     cache_udata.ctx_udata = dbg_ctx;
-    if(NULL == (hdr = (H5B2_hdr_t *)H5AC_protect(f, dxpl_id, H5AC_BT2_HDR, hdr_addr, &cache_udata, H5AC_READ)))
+    if(NULL == (hdr = (H5B2_hdr_t *)H5AC_protect(f, dxpl_id, H5AC_BT2_HDR, hdr_addr, &cache_udata, H5AC__READ_ONLY_FLAG)))
 	HGOTO_ERROR(H5E_BTREE, H5E_CANTPROTECT, FAIL, "unable to protect B-tree header")
 
     /* Set file pointer for this B-tree operation */
@@ -386,7 +389,7 @@ H5B2__leaf_debug(H5F_t *f, hid_t dxpl_id, haddr_t addr, FILE *stream, int indent
      * Load the B-tree leaf node
      */
     H5_CHECK_OVERFLOW(nrec, unsigned, uint16_t);
-    if(NULL == (leaf = H5B2__protect_leaf(hdr, dxpl_id, addr, (uint16_t)nrec, H5AC_READ)))
+    if(NULL == (leaf = H5B2__protect_leaf(hdr, dxpl_id, addr, (uint16_t)nrec, H5AC__READ_ONLY_FLAG)))
 	HGOTO_ERROR(H5E_BTREE, H5E_CANTPROTECT, FAIL, "unable to protect B-tree leaf node")
 
     /* Print opening message */
diff --git a/src/H5B2int.c b/src/H5B2int.c
index 638b4b3..0f884c2 100644
--- a/src/H5B2int.c
+++ b/src/H5B2int.c
@@ -215,9 +215,9 @@ H5B2__split1(H5B2_hdr_t *hdr, hid_t dxpl_id, uint16_t depth,
         right_addr = internal->node_ptrs[idx + 1].addr;
 
         /* Protect both leaves */
-        if(NULL == (left_int = H5B2__protect_internal(hdr, dxpl_id, left_addr, internal->node_ptrs[idx].node_nrec, (uint16_t)(depth - 1), H5AC_WRITE)))
+        if(NULL == (left_int = H5B2__protect_internal(hdr, dxpl_id, left_addr, internal->node_ptrs[idx].node_nrec, (uint16_t)(depth - 1), H5AC__NO_FLAGS_SET)))
             HGOTO_ERROR(H5E_BTREE, H5E_CANTPROTECT, FAIL, "unable to protect B-tree internal node")
-        if(NULL == (right_int = H5B2__protect_internal(hdr, dxpl_id, right_addr, internal->node_ptrs[idx + 1].node_nrec, (uint16_t)(depth - 1), H5AC_WRITE)))
+        if(NULL == (right_int = H5B2__protect_internal(hdr, dxpl_id, right_addr, internal->node_ptrs[idx + 1].node_nrec, (uint16_t)(depth - 1), H5AC__NO_FLAGS_SET)))
             HGOTO_ERROR(H5E_BTREE, H5E_CANTPROTECT, FAIL, "unable to protect B-tree internal node")
 
         /* More setup for child nodes */
@@ -244,9 +244,9 @@ H5B2__split1(H5B2_hdr_t *hdr, hid_t dxpl_id, uint16_t depth,
         right_addr = internal->node_ptrs[idx + 1].addr;
 
         /* Protect both leaves */
-        if(NULL == (left_leaf = H5B2__protect_leaf(hdr, dxpl_id, left_addr, internal->node_ptrs[idx].node_nrec, H5AC_WRITE)))
+        if(NULL == (left_leaf = H5B2__protect_leaf(hdr, dxpl_id, left_addr, internal->node_ptrs[idx].node_nrec, H5AC__NO_FLAGS_SET)))
             HGOTO_ERROR(H5E_BTREE, H5E_CANTPROTECT, FAIL, "unable to protect B-tree leaf node")
-        if(NULL == (right_leaf = H5B2__protect_leaf(hdr, dxpl_id, right_addr, internal->node_ptrs[idx + 1].node_nrec, H5AC_WRITE)))
+        if(NULL == (right_leaf = H5B2__protect_leaf(hdr, dxpl_id, right_addr, internal->node_ptrs[idx + 1].node_nrec, H5AC__NO_FLAGS_SET)))
             HGOTO_ERROR(H5E_BTREE, H5E_CANTPROTECT, FAIL, "unable to protect B-tree leaf node")
 
         /* More setup for child nodes */
@@ -403,7 +403,7 @@ H5B2__split_root(H5B2_hdr_t *hdr, hid_t dxpl_id)
         HGOTO_ERROR(H5E_BTREE, H5E_CANTINIT, FAIL, "unable to create new internal node")
 
     /* Protect new root node */
-    if(NULL == (new_root = H5B2__protect_internal(hdr, dxpl_id, hdr->root.addr, hdr->root.node_nrec, hdr->depth, H5AC_WRITE)))
+    if(NULL == (new_root = H5B2__protect_internal(hdr, dxpl_id, hdr->root.addr, hdr->root.node_nrec, hdr->depth, H5AC__NO_FLAGS_SET)))
         HGOTO_ERROR(H5E_BTREE, H5E_CANTPROTECT, FAIL, "unable to protect B-tree internal node")
 
     /* Set first node pointer in root node to old root node pointer info */
@@ -467,9 +467,9 @@ H5B2__redistribute2(H5B2_hdr_t *hdr, hid_t dxpl_id, uint16_t depth,
         right_addr = internal->node_ptrs[idx + 1].addr;
 
         /* Lock left & right B-tree child nodes */
-        if(NULL == (left_internal = H5B2__protect_internal(hdr, dxpl_id, left_addr, internal->node_ptrs[idx].node_nrec, (uint16_t)(depth - 1), H5AC_WRITE)))
+        if(NULL == (left_internal = H5B2__protect_internal(hdr, dxpl_id, left_addr, internal->node_ptrs[idx].node_nrec, (uint16_t)(depth - 1), H5AC__NO_FLAGS_SET)))
             HGOTO_ERROR(H5E_BTREE, H5E_CANTPROTECT, FAIL, "unable to protect B-tree leaf node")
-        if(NULL == (right_internal = H5B2__protect_internal(hdr, dxpl_id, right_addr, internal->node_ptrs[idx + 1].node_nrec, (uint16_t)(depth - 1), H5AC_WRITE)))
+        if(NULL == (right_internal = H5B2__protect_internal(hdr, dxpl_id, right_addr, internal->node_ptrs[idx + 1].node_nrec, (uint16_t)(depth - 1), H5AC__NO_FLAGS_SET)))
             HGOTO_ERROR(H5E_BTREE, H5E_CANTPROTECT, FAIL, "unable to protect B-tree leaf node")
 
         /* More setup for child nodes */
@@ -492,9 +492,9 @@ H5B2__redistribute2(H5B2_hdr_t *hdr, hid_t dxpl_id, uint16_t depth,
         right_addr = internal->node_ptrs[idx + 1].addr;
 
         /* Lock left & right B-tree child nodes */
-        if(NULL == (left_leaf = H5B2__protect_leaf(hdr, dxpl_id, left_addr, internal->node_ptrs[idx].node_nrec, H5AC_WRITE)))
+        if(NULL == (left_leaf = H5B2__protect_leaf(hdr, dxpl_id, left_addr, internal->node_ptrs[idx].node_nrec, H5AC__NO_FLAGS_SET)))
             HGOTO_ERROR(H5E_BTREE, H5E_CANTPROTECT, FAIL, "unable to protect B-tree leaf node")
-        if(NULL == (right_leaf = H5B2__protect_leaf(hdr, dxpl_id, right_addr, internal->node_ptrs[idx + 1].node_nrec, H5AC_WRITE)))
+        if(NULL == (right_leaf = H5B2__protect_leaf(hdr, dxpl_id, right_addr, internal->node_ptrs[idx + 1].node_nrec, H5AC__NO_FLAGS_SET)))
             HGOTO_ERROR(H5E_BTREE, H5E_CANTPROTECT, FAIL, "unable to protect B-tree leaf node")
 
         /* More setup for child nodes */
@@ -704,11 +704,11 @@ H5B2__redistribute3(H5B2_hdr_t *hdr, hid_t dxpl_id, uint16_t depth,
         right_addr = internal->node_ptrs[idx + 1].addr;
 
         /* Lock B-tree child nodes */
-        if(NULL == (left_internal = H5B2__protect_internal(hdr, dxpl_id, left_addr, internal->node_ptrs[idx - 1].node_nrec, (uint16_t)(depth - 1), H5AC_WRITE)))
+        if(NULL == (left_internal = H5B2__protect_internal(hdr, dxpl_id, left_addr, internal->node_ptrs[idx - 1].node_nrec, (uint16_t)(depth - 1), H5AC__NO_FLAGS_SET)))
             HGOTO_ERROR(H5E_BTREE, H5E_CANTPROTECT, FAIL, "unable to protect B-tree internal node")
-        if(NULL == (middle_internal = H5B2__protect_internal(hdr, dxpl_id, middle_addr, internal->node_ptrs[idx].node_nrec, (uint16_t)(depth - 1), H5AC_WRITE)))
+        if(NULL == (middle_internal = H5B2__protect_internal(hdr, dxpl_id, middle_addr, internal->node_ptrs[idx].node_nrec, (uint16_t)(depth - 1), H5AC__NO_FLAGS_SET)))
             HGOTO_ERROR(H5E_BTREE, H5E_CANTPROTECT, FAIL, "unable to protect B-tree internal node")
-        if(NULL == (right_internal = H5B2__protect_internal(hdr, dxpl_id, right_addr, internal->node_ptrs[idx + 1].node_nrec, (uint16_t)(depth - 1), H5AC_WRITE)))
+        if(NULL == (right_internal = H5B2__protect_internal(hdr, dxpl_id, right_addr, internal->node_ptrs[idx + 1].node_nrec, (uint16_t)(depth - 1), H5AC__NO_FLAGS_SET)))
             HGOTO_ERROR(H5E_BTREE, H5E_CANTPROTECT, FAIL, "unable to protect B-tree internal node")
 
         /* More setup for child nodes */
@@ -737,11 +737,11 @@ H5B2__redistribute3(H5B2_hdr_t *hdr, hid_t dxpl_id, uint16_t depth,
         right_addr = internal->node_ptrs[idx + 1].addr;
 
         /* Lock B-tree child nodes */
-        if(NULL == (left_leaf = H5B2__protect_leaf(hdr, dxpl_id, left_addr, internal->node_ptrs[idx - 1].node_nrec, H5AC_WRITE)))
+        if(NULL == (left_leaf = H5B2__protect_leaf(hdr, dxpl_id, left_addr, internal->node_ptrs[idx - 1].node_nrec, H5AC__NO_FLAGS_SET)))
             HGOTO_ERROR(H5E_BTREE, H5E_CANTPROTECT, FAIL, "unable to protect B-tree leaf node")
-        if(NULL == (middle_leaf = H5B2__protect_leaf(hdr, dxpl_id, middle_addr, internal->node_ptrs[idx].node_nrec, H5AC_WRITE)))
+        if(NULL == (middle_leaf = H5B2__protect_leaf(hdr, dxpl_id, middle_addr, internal->node_ptrs[idx].node_nrec, H5AC__NO_FLAGS_SET)))
             HGOTO_ERROR(H5E_BTREE, H5E_CANTPROTECT, FAIL, "unable to protect B-tree leaf node")
-        if(NULL == (right_leaf = H5B2__protect_leaf(hdr, dxpl_id, right_addr, internal->node_ptrs[idx + 1].node_nrec, H5AC_WRITE)))
+        if(NULL == (right_leaf = H5B2__protect_leaf(hdr, dxpl_id, right_addr, internal->node_ptrs[idx + 1].node_nrec, H5AC__NO_FLAGS_SET)))
             HGOTO_ERROR(H5E_BTREE, H5E_CANTPROTECT, FAIL, "unable to protect B-tree leaf node")
 
         /* More setup for child nodes */
@@ -1084,9 +1084,9 @@ H5B2__merge2(H5B2_hdr_t *hdr, hid_t dxpl_id, uint16_t depth,
         right_addr = internal->node_ptrs[idx + 1].addr;
 
         /* Lock left & right B-tree child nodes */
-        if(NULL == (left_internal = H5B2__protect_internal(hdr, dxpl_id, left_addr, internal->node_ptrs[idx].node_nrec, (uint16_t)(depth - 1), H5AC_WRITE)))
+        if(NULL == (left_internal = H5B2__protect_internal(hdr, dxpl_id, left_addr, internal->node_ptrs[idx].node_nrec, (uint16_t)(depth - 1), H5AC__NO_FLAGS_SET)))
             HGOTO_ERROR(H5E_BTREE, H5E_CANTPROTECT, FAIL, "unable to protect B-tree internal node")
-        if(NULL == (right_internal = H5B2__protect_internal(hdr, dxpl_id, right_addr, internal->node_ptrs[idx + 1].node_nrec, (uint16_t)(depth - 1), H5AC_WRITE)))
+        if(NULL == (right_internal = H5B2__protect_internal(hdr, dxpl_id, right_addr, internal->node_ptrs[idx + 1].node_nrec, (uint16_t)(depth - 1), H5AC__NO_FLAGS_SET)))
             HGOTO_ERROR(H5E_BTREE, H5E_CANTPROTECT, FAIL, "unable to protect B-tree internal node")
 
         /* More setup for accessing child node information */
@@ -1109,9 +1109,9 @@ H5B2__merge2(H5B2_hdr_t *hdr, hid_t dxpl_id, uint16_t depth,
         right_addr = internal->node_ptrs[idx + 1].addr;
 
         /* Lock left & right B-tree child nodes */
-        if(NULL == (left_leaf = H5B2__protect_leaf(hdr, dxpl_id, left_addr, internal->node_ptrs[idx].node_nrec, H5AC_WRITE)))
+        if(NULL == (left_leaf = H5B2__protect_leaf(hdr, dxpl_id, left_addr, internal->node_ptrs[idx].node_nrec, H5AC__NO_FLAGS_SET)))
             HGOTO_ERROR(H5E_BTREE, H5E_CANTPROTECT, FAIL, "unable to protect B-tree leaf node")
-        if(NULL == (right_leaf = H5B2__protect_leaf(hdr, dxpl_id, right_addr, internal->node_ptrs[idx + 1].node_nrec, H5AC_WRITE)))
+        if(NULL == (right_leaf = H5B2__protect_leaf(hdr, dxpl_id, right_addr, internal->node_ptrs[idx + 1].node_nrec, H5AC__NO_FLAGS_SET)))
             HGOTO_ERROR(H5E_BTREE, H5E_CANTPROTECT, FAIL, "unable to protect B-tree leaf node")
 
         /* More setup for accessing child node information */
@@ -1246,11 +1246,11 @@ H5B2__merge3(H5B2_hdr_t *hdr, hid_t dxpl_id, uint16_t depth,
         right_addr = internal->node_ptrs[idx + 1].addr;
 
         /* Lock B-tree child nodes */
-        if(NULL == (left_internal = H5B2__protect_internal(hdr, dxpl_id, left_addr, internal->node_ptrs[idx - 1].node_nrec, (uint16_t)(depth - 1), H5AC_WRITE)))
+        if(NULL == (left_internal = H5B2__protect_internal(hdr, dxpl_id, left_addr, internal->node_ptrs[idx - 1].node_nrec, (uint16_t)(depth - 1), H5AC__NO_FLAGS_SET)))
             HGOTO_ERROR(H5E_BTREE, H5E_CANTPROTECT, FAIL, "unable to protect B-tree internal node")
-        if(NULL == (middle_internal = H5B2__protect_internal(hdr, dxpl_id, middle_addr, internal->node_ptrs[idx].node_nrec, (uint16_t)(depth - 1), H5AC_WRITE)))
+        if(NULL == (middle_internal = H5B2__protect_internal(hdr, dxpl_id, middle_addr, internal->node_ptrs[idx].node_nrec, (uint16_t)(depth - 1), H5AC__NO_FLAGS_SET)))
             HGOTO_ERROR(H5E_BTREE, H5E_CANTPROTECT, FAIL, "unable to protect B-tree internal node")
-        if(NULL == (right_internal = H5B2__protect_internal(hdr, dxpl_id, right_addr, internal->node_ptrs[idx + 1].node_nrec, (uint16_t)(depth - 1), H5AC_WRITE)))
+        if(NULL == (right_internal = H5B2__protect_internal(hdr, dxpl_id, right_addr, internal->node_ptrs[idx + 1].node_nrec, (uint16_t)(depth - 1), H5AC__NO_FLAGS_SET)))
             HGOTO_ERROR(H5E_BTREE, H5E_CANTPROTECT, FAIL, "unable to protect B-tree internal node")
 
         /* More setup for accessing child node information */
@@ -1279,11 +1279,11 @@ H5B2__merge3(H5B2_hdr_t *hdr, hid_t dxpl_id, uint16_t depth,
         right_addr = internal->node_ptrs[idx + 1].addr;
 
         /* Lock B-tree child nodes */
-        if(NULL == (left_leaf = H5B2__protect_leaf(hdr, dxpl_id, left_addr, internal->node_ptrs[idx - 1].node_nrec, H5AC_WRITE)))
+        if(NULL == (left_leaf = H5B2__protect_leaf(hdr, dxpl_id, left_addr, internal->node_ptrs[idx - 1].node_nrec, H5AC__NO_FLAGS_SET)))
             HGOTO_ERROR(H5E_BTREE, H5E_CANTPROTECT, FAIL, "unable to protect B-tree leaf node")
-        if(NULL == (middle_leaf = H5B2__protect_leaf(hdr, dxpl_id, middle_addr, internal->node_ptrs[idx].node_nrec, H5AC_WRITE)))
+        if(NULL == (middle_leaf = H5B2__protect_leaf(hdr, dxpl_id, middle_addr, internal->node_ptrs[idx].node_nrec, H5AC__NO_FLAGS_SET)))
             HGOTO_ERROR(H5E_BTREE, H5E_CANTPROTECT, FAIL, "unable to protect B-tree leaf node")
-        if(NULL == (right_leaf = H5B2__protect_leaf(hdr, dxpl_id, right_addr, internal->node_ptrs[idx + 1].node_nrec, H5AC_WRITE)))
+        if(NULL == (right_leaf = H5B2__protect_leaf(hdr, dxpl_id, right_addr, internal->node_ptrs[idx + 1].node_nrec, H5AC__NO_FLAGS_SET)))
             HGOTO_ERROR(H5E_BTREE, H5E_CANTPROTECT, FAIL, "unable to protect B-tree leaf node")
 
         /* More setup for accessing child node information */
@@ -1460,7 +1460,7 @@ H5B2__swap_leaf(H5B2_hdr_t *hdr, hid_t dxpl_id, uint16_t depth,
         child_addr = internal->node_ptrs[idx].addr;
 
         /* Lock B-tree child nodes */
-        if(NULL == (child_internal = H5B2__protect_internal(hdr, dxpl_id, child_addr, internal->node_ptrs[idx].node_nrec, (uint16_t)(depth - 1), H5AC_WRITE)))
+        if(NULL == (child_internal = H5B2__protect_internal(hdr, dxpl_id, child_addr, internal->node_ptrs[idx].node_nrec, (uint16_t)(depth - 1), H5AC__NO_FLAGS_SET)))
             HGOTO_ERROR(H5E_BTREE, H5E_CANTPROTECT, FAIL, "unable to protect B-tree internal node")
 
         /* More setup for accessing child node information */
@@ -1475,7 +1475,7 @@ H5B2__swap_leaf(H5B2_hdr_t *hdr, hid_t dxpl_id, uint16_t depth,
         child_addr = internal->node_ptrs[idx].addr;
 
         /* Lock B-tree child node */
-        if(NULL == (child_leaf = H5B2__protect_leaf(hdr, dxpl_id, child_addr, internal->node_ptrs[idx].node_nrec, H5AC_WRITE)))
+        if(NULL == (child_leaf = H5B2__protect_leaf(hdr, dxpl_id, child_addr, internal->node_ptrs[idx].node_nrec, H5AC__NO_FLAGS_SET)))
             HGOTO_ERROR(H5E_BTREE, H5E_CANTPROTECT, FAIL, "unable to protect B-tree leaf node")
 
         /* More setup for accessing child node information */
@@ -1538,7 +1538,7 @@ H5B2__insert_leaf(H5B2_hdr_t *hdr, hid_t dxpl_id, H5B2_node_ptr_t *curr_node_ptr
     HDassert(H5F_addr_defined(curr_node_ptr->addr));
 
     /* Lock current B-tree node */
-    if(NULL == (leaf = H5B2__protect_leaf(hdr, dxpl_id, curr_node_ptr->addr, curr_node_ptr->node_nrec, H5AC_WRITE)))
+    if(NULL == (leaf = H5B2__protect_leaf(hdr, dxpl_id, curr_node_ptr->addr, curr_node_ptr->node_nrec, H5AC__NO_FLAGS_SET)))
         HGOTO_ERROR(H5E_BTREE, H5E_CANTPROTECT, FAIL, "unable to protect B-tree leaf node")
 
     /* Must have a leaf node with enough space to insert a record now */
@@ -1637,7 +1637,7 @@ H5B2__insert_internal(H5B2_hdr_t *hdr, hid_t dxpl_id, uint16_t depth,
     HDassert(H5F_addr_defined(curr_node_ptr->addr));
 
     /* Lock current B-tree node */
-    if(NULL == (internal = H5B2__protect_internal(hdr, dxpl_id, curr_node_ptr->addr, curr_node_ptr->node_nrec, depth, H5AC_WRITE)))
+    if(NULL == (internal = H5B2__protect_internal(hdr, dxpl_id, curr_node_ptr->addr, curr_node_ptr->node_nrec, depth, H5AC__NO_FLAGS_SET)))
         HGOTO_ERROR(H5E_BTREE, H5E_CANTPROTECT, FAIL, "unable to protect B-tree internal node")
 
     /* Split or redistribute child node pointers, if necessary */
@@ -1834,7 +1834,7 @@ done:
  */
 H5B2_leaf_t *
 H5B2__protect_leaf(H5B2_hdr_t *hdr, hid_t dxpl_id, haddr_t addr, uint16_t nrec,
-    H5AC_protect_t rw)
+    unsigned flags)
 {
     H5B2_leaf_cache_ud_t udata;         /* User-data for callback */
     H5B2_leaf_t *ret_value;             /* Return value */
@@ -1845,13 +1845,16 @@ H5B2__protect_leaf(H5B2_hdr_t *hdr, hid_t dxpl_id, haddr_t addr, uint16_t nrec,
     HDassert(hdr);
     HDassert(H5F_addr_defined(addr));
 
+    /* only H5AC__READ_ONLY_FLAG may appear in flags */
+    HDassert((flags & (unsigned)(~H5AC__READ_ONLY_FLAG)) == 0);
+
     /* Set up user data for callback */
     udata.f = hdr->f;
     udata.hdr = hdr;
     H5_CHECKED_ASSIGN(udata.nrec, uint16_t, nrec, unsigned)
 
     /* Protect the leaf node */
-    if(NULL == (ret_value = (H5B2_leaf_t *)H5AC_protect(hdr->f, dxpl_id, H5AC_BT2_LEAF, addr, &udata, rw)))
+    if(NULL == (ret_value = (H5B2_leaf_t *)H5AC_protect(hdr->f, dxpl_id, H5AC_BT2_LEAF, addr, &udata, flags)))
         HGOTO_ERROR(H5E_BTREE, H5E_CANTPROTECT, NULL, "unable to protect B-tree leaf node")
 
 done:
@@ -1953,7 +1956,7 @@ done:
  */
 H5B2_internal_t *
 H5B2__protect_internal(H5B2_hdr_t *hdr, hid_t dxpl_id, haddr_t addr,
-    uint16_t nrec, uint16_t depth, H5AC_protect_t rw)
+    uint16_t nrec, uint16_t depth, unsigned flags)
 {
     H5B2_internal_cache_ud_t udata;     /* User data to pass through to cache 'deserialize' callback */
     H5B2_internal_t *ret_value;         /* Return value */
@@ -1965,6 +1968,9 @@ H5B2__protect_internal(H5B2_hdr_t *hdr, hid_t dxpl_id, haddr_t addr,
     HDassert(H5F_addr_defined(addr));
     HDassert(depth > 0);
 
+    /* only H5AC__READ_ONLY_FLAG may appear in flags */
+    HDassert((flags & (unsigned)(~H5AC__READ_ONLY_FLAG)) == 0);
+
     /* Set up user data for callback */
     udata.f = hdr->f;
     udata.hdr = hdr;
@@ -1972,7 +1978,7 @@ H5B2__protect_internal(H5B2_hdr_t *hdr, hid_t dxpl_id, haddr_t addr,
     udata.depth = depth;
 
     /* Protect the internal node */
-    if(NULL == (ret_value = (H5B2_internal_t *)H5AC_protect(hdr->f, dxpl_id, H5AC_BT2_INT, addr, &udata, rw)))
+    if(NULL == (ret_value = (H5B2_internal_t *)H5AC_protect(hdr->f, dxpl_id, H5AC_BT2_INT, addr, &udata, flags)))
         HGOTO_ERROR(H5E_BTREE, H5E_CANTPROTECT, NULL, "unable to protect B-tree internal node")
 
 done:
@@ -2021,7 +2027,7 @@ H5B2__iterate_node(H5B2_hdr_t *hdr, hid_t dxpl_id, uint16_t depth,
         H5B2_internal_t *internal;     /* Pointer to internal node */
 
         /* Lock the current B-tree node */
-        if(NULL == (internal = H5B2__protect_internal(hdr, dxpl_id, curr_node->addr, curr_node->node_nrec, depth, H5AC_READ)))
+        if(NULL == (internal = H5B2__protect_internal(hdr, dxpl_id, curr_node->addr, curr_node->node_nrec, depth, H5AC__READ_ONLY_FLAG)))
             HGOTO_ERROR(H5E_BTREE, H5E_CANTPROTECT, FAIL, "unable to protect B-tree internal node")
 
         /* Set up information about current node */
@@ -2040,7 +2046,7 @@ H5B2__iterate_node(H5B2_hdr_t *hdr, hid_t dxpl_id, uint16_t depth,
         H5B2_leaf_t *leaf;             /* Pointer to leaf node */
 
         /* Lock the current B-tree node */
-        if(NULL == (leaf = H5B2__protect_leaf(hdr, dxpl_id, curr_node->addr, curr_node->node_nrec, H5AC_READ)))
+        if(NULL == (leaf = H5B2__protect_leaf(hdr, dxpl_id, curr_node->addr, curr_node->node_nrec, H5AC__READ_ONLY_FLAG)))
             HGOTO_ERROR(H5E_BTREE, H5E_CANTPROTECT, FAIL, "unable to protect B-tree leaf node")
 
         /* Set up information about current node */
@@ -2125,7 +2131,7 @@ H5B2__remove_leaf(H5B2_hdr_t *hdr, hid_t dxpl_id, H5B2_node_ptr_t *curr_node_ptr
 
     /* Lock current B-tree node */
     leaf_addr = curr_node_ptr->addr;
-    if(NULL == (leaf = H5B2__protect_leaf(hdr, dxpl_id, leaf_addr, curr_node_ptr->node_nrec, H5AC_WRITE)))
+    if(NULL == (leaf = H5B2__protect_leaf(hdr, dxpl_id, leaf_addr, curr_node_ptr->node_nrec, H5AC__NO_FLAGS_SET)))
         HGOTO_ERROR(H5E_BTREE, H5E_CANTPROTECT, FAIL, "unable to protect B-tree leaf node")
 
     /* Sanity check number of records */
@@ -2234,7 +2240,7 @@ H5B2__remove_internal(H5B2_hdr_t *hdr, hid_t dxpl_id, hbool_t *depth_decreased,
 
     /* Lock current B-tree node */
     internal_addr = curr_node_ptr->addr;
-    if(NULL == (internal = H5B2__protect_internal(hdr, dxpl_id, internal_addr, curr_node_ptr->node_nrec, depth, H5AC_WRITE)))
+    if(NULL == (internal = H5B2__protect_internal(hdr, dxpl_id, internal_addr, curr_node_ptr->node_nrec, depth, H5AC__NO_FLAGS_SET)))
         HGOTO_ERROR(H5E_BTREE, H5E_CANTPROTECT, FAIL, "unable to protect B-tree internal node")
 
     /* Determine the correct number of records to merge at */
@@ -2443,7 +2449,7 @@ H5B2__remove_leaf_by_idx(H5B2_hdr_t *hdr, hid_t dxpl_id,
 
     /* Lock B-tree leaf node */
     leaf_addr = curr_node_ptr->addr;
-    if(NULL == (leaf = H5B2__protect_leaf(hdr, dxpl_id, leaf_addr, curr_node_ptr->node_nrec, H5AC_WRITE)))
+    if(NULL == (leaf = H5B2__protect_leaf(hdr, dxpl_id, leaf_addr, curr_node_ptr->node_nrec, H5AC__NO_FLAGS_SET)))
         HGOTO_ERROR(H5E_BTREE, H5E_CANTPROTECT, FAIL, "unable to protect B-tree leaf node")
 
     /* Sanity check number of records */
@@ -2551,7 +2557,7 @@ H5B2__remove_internal_by_idx(H5B2_hdr_t *hdr, hid_t dxpl_id,
 
     /* Lock current B-tree node */
     internal_addr = curr_node_ptr->addr;
-    if(NULL == (internal = H5B2__protect_internal(hdr, dxpl_id, internal_addr, curr_node_ptr->node_nrec, depth, H5AC_WRITE)))
+    if(NULL == (internal = H5B2__protect_internal(hdr, dxpl_id, internal_addr, curr_node_ptr->node_nrec, depth, H5AC__NO_FLAGS_SET)))
         HGOTO_ERROR(H5E_BTREE, H5E_CANTPROTECT, FAIL, "unable to protect B-tree internal node")
     HDassert(internal->nrec == curr_node_ptr->node_nrec);
     HDassert(depth == hdr->depth || internal->nrec > 1);
@@ -2827,7 +2833,7 @@ H5B2__neighbor_leaf(H5B2_hdr_t *hdr, hid_t dxpl_id, H5B2_node_ptr_t *curr_node_p
     HDassert(op);
 
     /* Lock current B-tree node */
-    if(NULL == (leaf = H5B2__protect_leaf(hdr, dxpl_id, curr_node_ptr->addr, curr_node_ptr->node_nrec, H5AC_READ)))
+    if(NULL == (leaf = H5B2__protect_leaf(hdr, dxpl_id, curr_node_ptr->addr, curr_node_ptr->node_nrec, H5AC__READ_ONLY_FLAG)))
         HGOTO_ERROR(H5E_BTREE, H5E_CANTPROTECT, FAIL, "unable to protect B-tree leaf node")
 
     /* Locate node pointer for child */
@@ -2914,7 +2920,7 @@ H5B2__neighbor_internal(H5B2_hdr_t *hdr, hid_t dxpl_id, uint16_t depth,
     HDassert(op);
 
     /* Lock current B-tree node */
-    if(NULL == (internal = H5B2__protect_internal(hdr, dxpl_id, curr_node_ptr->addr, curr_node_ptr->node_nrec, depth, H5AC_READ)))
+    if(NULL == (internal = H5B2__protect_internal(hdr, dxpl_id, curr_node_ptr->addr, curr_node_ptr->node_nrec, depth, H5AC__READ_ONLY_FLAG)))
         HGOTO_ERROR(H5E_BTREE, H5E_CANTPROTECT, FAIL, "unable to protect B-tree internal node")
 
     /* Locate node pointer for child */
@@ -2987,7 +2993,7 @@ H5B2__delete_node(H5B2_hdr_t *hdr, hid_t dxpl_id, uint16_t depth,
         unsigned u;                    /* Local index */
 
         /* Lock the current B-tree node */
-        if(NULL == (internal = H5B2__protect_internal(hdr, dxpl_id, curr_node->addr, curr_node->node_nrec, depth, H5AC_WRITE)))
+        if(NULL == (internal = H5B2__protect_internal(hdr, dxpl_id, curr_node->addr, curr_node->node_nrec, depth, H5AC__NO_FLAGS_SET)))
             HGOTO_ERROR(H5E_BTREE, H5E_CANTPROTECT, FAIL, "unable to protect B-tree internal node")
 
         /* Set up information about current node */
@@ -3004,7 +3010,7 @@ H5B2__delete_node(H5B2_hdr_t *hdr, hid_t dxpl_id, uint16_t depth,
         H5B2_leaf_t *leaf;             /* Pointer to leaf node */
 
         /* Lock the current B-tree node */
-        if(NULL == (leaf = H5B2__protect_leaf(hdr, dxpl_id, curr_node->addr, curr_node->node_nrec, H5AC_WRITE)))
+        if(NULL == (leaf = H5B2__protect_leaf(hdr, dxpl_id, curr_node->addr, curr_node->node_nrec, H5AC__NO_FLAGS_SET)))
             HGOTO_ERROR(H5E_BTREE, H5E_CANTPROTECT, FAIL, "unable to protect B-tree leaf node")
 
         /* Set up information about current node */
@@ -3063,7 +3069,7 @@ H5B2__node_size(H5B2_hdr_t *hdr, hid_t dxpl_id, uint16_t depth,
     HDassert(depth > 0);
 
     /* Lock the current B-tree node */
-    if(NULL == (internal = H5B2__protect_internal(hdr, dxpl_id, curr_node->addr, curr_node->node_nrec, depth, H5AC_READ)))
+    if(NULL == (internal = H5B2__protect_internal(hdr, dxpl_id, curr_node->addr, curr_node->node_nrec, depth, H5AC__READ_ONLY_FLAG)))
         HGOTO_ERROR(H5E_BTREE, H5E_CANTPROTECT, FAIL, "unable to protect B-tree internal node")
 
     /* Recursively descend into child nodes, if we are above the "twig" level in the B-tree */
diff --git a/src/H5B2pkg.h b/src/H5B2pkg.h
index a2d32e6..b13c58d 100644
--- a/src/H5B2pkg.h
+++ b/src/H5B2pkg.h
@@ -231,6 +231,7 @@ typedef enum H5B2_nodepos_t {
 /* Callback info for loading a free space header into the cache */
 typedef struct H5B2_hdr_cache_ud_t {
     H5F_t *f;                   /* File that v2 b-tree header is within */
+    haddr_t addr;               /* Address of B-tree header in the file */
     void *ctx_udata;            /* User-data for protecting */
 } H5B2_hdr_cache_ud_t;
 
@@ -305,11 +306,11 @@ H5_DLL herr_t H5B2__hdr_delete(H5B2_hdr_t *hdr, hid_t dxpl_id);
 
 /* Routines for operating on leaf nodes */
 H5B2_leaf_t *H5B2__protect_leaf(H5B2_hdr_t *hdr, hid_t dxpl_id, haddr_t addr,
-    uint16_t nrec, H5AC_protect_t rw);
+    uint16_t nrec, unsigned flags);
 
 /* Routines for operating on internal nodes */
 H5_DLL H5B2_internal_t *H5B2__protect_internal(H5B2_hdr_t *hdr, hid_t dxpl_id,
-    haddr_t addr, uint16_t nrec, uint16_t depth, H5AC_protect_t rw);
+    haddr_t addr, uint16_t nrec, uint16_t depth, unsigned flags);
 
 /* Routines for allocating nodes */
 H5_DLL herr_t H5B2__split_root(H5B2_hdr_t *hdr, hid_t dxpl_id);
@@ -347,7 +348,7 @@ H5_DLL herr_t H5B2__neighbor_leaf(H5B2_hdr_t *hdr, hid_t dxpl_id,
 /* Routines for removing records */
 H5_DLL herr_t H5B2__remove_internal(H5B2_hdr_t *hdr, hid_t dxpl_id,
     hbool_t *depth_decreased, void *swap_loc, uint16_t depth,
-    H5AC_info_t *parent_cache_info, hbool_t *parent_cache_info_dirtied_ptr,
+    H5AC_info_t *parent_cache_info, unsigned *parent_cache_info_flags_ptr,
     H5B2_nodepos_t curr_pos, H5B2_node_ptr_t *curr_node_ptr, void *udata,
     H5B2_remove_t op, void *op_data);
 H5_DLL herr_t H5B2__remove_leaf(H5B2_hdr_t *hdr, hid_t dxpl_id,
@@ -355,8 +356,8 @@ H5_DLL herr_t H5B2__remove_leaf(H5B2_hdr_t *hdr, hid_t dxpl_id,
     void *udata, H5B2_remove_t op, void *op_data);
 H5_DLL herr_t H5B2__remove_internal_by_idx(H5B2_hdr_t *hdr, hid_t dxpl_id,
     hbool_t *depth_decreased, void *swap_loc, uint16_t depth,
-    H5AC_info_t *parent_cache_info, hbool_t *parent_cache_info_dirtied_ptr,
-    H5B2_node_ptr_t *curr_node_ptr, H5B2_nodepos_t curr_pos, hsize_t idx,
+    H5AC_info_t *parent_cache_info, unsigned *parent_cache_info_flags_ptr,
+    H5B2_node_ptr_t *curr_node_ptr, H5B2_nodepos_t curr_pos, hsize_t n,
     H5B2_remove_t op, void *op_data);
 H5_DLL herr_t H5B2__remove_leaf_by_idx(H5B2_hdr_t *hdr, hid_t dxpl_id,
     H5B2_node_ptr_t *curr_node_ptr, H5B2_nodepos_t curr_pos,
diff --git a/src/H5B2test.c b/src/H5B2test.c
index 1d31af8..35771f2 100644
--- a/src/H5B2test.c
+++ b/src/H5B2test.c
@@ -430,7 +430,7 @@ H5B2_get_node_info_test(H5B2_t *bt2, hid_t dxpl_id, void *udata,
         H5B2_node_ptr_t next_node_ptr;      /* Node pointer info for next node */
 
         /* Lock B-tree current node */
-        if(NULL == (internal = H5B2__protect_internal(hdr, dxpl_id, curr_node_ptr.addr, curr_node_ptr.node_nrec, depth, H5AC_READ)))
+        if(NULL == (internal = H5B2__protect_internal(hdr, dxpl_id, curr_node_ptr.addr, curr_node_ptr.node_nrec, depth, H5AC__READ_ONLY_FLAG)))
             HGOTO_ERROR(H5E_BTREE, H5E_CANTPROTECT, FAIL, "unable to load B-tree internal node")
 
         /* Locate node pointer for child */
@@ -470,7 +470,7 @@ H5B2_get_node_info_test(H5B2_t *bt2, hid_t dxpl_id, void *udata,
         H5B2_leaf_t *leaf;          /* Pointer to leaf node in B-tree */
 
         /* Lock B-tree leaf node */
-        if(NULL == (leaf = H5B2__protect_leaf(hdr, dxpl_id, curr_node_ptr.addr, curr_node_ptr.node_nrec, H5AC_READ)))
+        if(NULL == (leaf = H5B2__protect_leaf(hdr, dxpl_id, curr_node_ptr.addr, curr_node_ptr.node_nrec, H5AC__READ_ONLY_FLAG)))
             HGOTO_ERROR(H5E_BTREE, H5E_CANTPROTECT, FAIL, "unable to protect B-tree leaf node")
 
         /* Locate record */
diff --git a/src/H5Bcache.c b/src/H5Bcache.c
index a161e88..dfa4dab 100644
--- a/src/H5Bcache.c
+++ b/src/H5Bcache.c
@@ -37,7 +37,6 @@
 #include "H5private.h"		/* Generic Functions			*/
 #include "H5Bpkg.h"		/* B-link trees				*/
 #include "H5Eprivate.h"		/* Error handling		  	*/
-#include "H5MFprivate.h"	/* File memory management		*/
 
 
 /****************/
@@ -55,11 +54,14 @@
 /********************/
 
 /* Metadata cache callbacks */
-static H5B_t *H5B__load(H5F_t *f, hid_t dxpl_id, haddr_t addr, void *udata);
-static herr_t H5B__flush(H5F_t *f, hid_t dxpl_id, hbool_t destroy, haddr_t addr, H5B_t *b, unsigned H5_ATTR_UNUSED * flags_ptr);
-static herr_t H5B__dest(H5F_t *f, H5B_t *bt);
-static herr_t H5B__clear(H5F_t *f, H5B_t *b, hbool_t destroy);
-static herr_t H5B__compute_size(const H5F_t *f, const H5B_t *bt, size_t *size_ptr);
+static herr_t H5B__get_load_size(const void *udata, size_t *image_len);
+static void *H5B__deserialize(const void *image, size_t len, void *udata,
+    hbool_t *dirty);
+static herr_t H5B__image_len(const void *thing, size_t *image_len, 
+    hbool_t *compressed_ptr, size_t *compressed_image_len_ptr);
+static herr_t H5B__serialize(const H5F_t *f, void *image, size_t len,
+    void *thing);
+static herr_t H5B__free_icr(void *thing);
 
 
 /*********************/
@@ -68,13 +70,19 @@ static herr_t H5B__compute_size(const H5F_t *f, const H5B_t *bt, size_t *size_pt
 
 /* H5B inherits cache-like properties from H5AC */
 const H5AC_class_t H5AC_BT[1] = {{
-    H5AC_BT_ID,
-    (H5AC_load_func_t)H5B__load,
-    (H5AC_flush_func_t)H5B__flush,
-    (H5AC_dest_func_t)H5B__dest,
-    (H5AC_clear_func_t)H5B__clear,
-    (H5AC_notify_func_t)NULL,
-    (H5AC_size_func_t)H5B__compute_size,
+    H5AC_BT_ID,                         /* Metadata client ID */
+    "v1 B-tree",                        /* Metadata client name (for debugging) */
+    H5FD_MEM_BTREE,                     /* File space memory type for client */
+    H5AC__CLASS_NO_FLAGS_SET,           /* Client class behavior flags */
+    H5B__get_load_size,                 /* 'get_load_size' callback */
+    H5B__deserialize,                   /* 'deserialize' callback */
+    H5B__image_len,                     /* 'image_len' callback */
+    NULL,                               /* 'pre_serialize' callback */
+    H5B__serialize,                     /* 'serialize' callback */
+    NULL,                               /* 'notify' callback */
+    H5B__free_icr,                      /* 'free_icr' callback */
+    NULL,				/* 'clear" callback */
+    NULL,                               /* 'fsf_size' callback */
 }};
 
 /*******************/
@@ -84,35 +92,71 @@ const H5AC_class_t H5AC_BT[1] = {{
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5B__load
+ * Function:    H5B__get_load_size
  *
- * Purpose:	Loads a B-tree node from the disk.
+ * Purpose:     Compute the size of the data structure on disk.
+ *
+ * Return:      Non-negative on success/Negative on failure
+ *
+ * Programmer:  Quincey Koziol
+ *              koziol@hdfgroup.org
+ *              May 18, 2010
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+H5B__get_load_size(const void *_udata, size_t *image_len)
+{
+    const H5B_cache_ud_t *udata = (const H5B_cache_ud_t *)_udata;       /* User data for callback */
+    H5B_shared_t *shared;       /* Pointer to shared B-tree info */
+
+    FUNC_ENTER_STATIC_NOERR
+
+    /* Check arguments */
+    HDassert(udata);
+    HDassert(image_len);
+
+    /* Get shared info for B-tree */
+    shared = (H5B_shared_t *)H5UC_GET_OBJ(udata->rc_shared);
+    HDassert(shared);
+
+    /* Set the image length size */
+    *image_len = shared->sizeof_rnode;
+
+    FUNC_LEAVE_NOAPI(SUCCEED)
+} /* end H5B__get_load_size() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:    H5B__deserialize
+ *
+ * Purpose:     Deserialize the data structure from disk.
  *
  * Return:	Success:	Pointer to a new B-tree node.
  *		Failure:	NULL
  *
- * Programmer:	Robb Matzke
- *		matzke@llnl.gov
- *		Jun 23 1997
+ * Programmer:  Quincey Koziol
+ *              koziol@hdfgroup.org
+ *              Mar 24, 2008
  *
  *-------------------------------------------------------------------------
  */
-static H5B_t *
-H5B__load(H5F_t *f, hid_t dxpl_id, haddr_t addr, void *_udata)
+static void *
+H5B__deserialize(const void *_image, size_t H5_ATTR_UNUSED len, void *_udata,
+    hbool_t H5_ATTR_UNUSED *dirty)
 {
     H5B_t *bt = NULL;           /* Pointer to the deserialized B-tree node */
     H5B_cache_ud_t *udata = (H5B_cache_ud_t *)_udata;       /* User data for callback */
     H5B_shared_t *shared;       /* Pointer to shared B-tree info */
-    const uint8_t *p;           /* Pointer into raw data buffer */
+    const uint8_t *image = (const uint8_t *)_image;     /* Pointer into image buffer */
     uint8_t *native;            /* Pointer to native keys */
     unsigned u;                 /* Local index variable */
     H5B_t *ret_value;           /* Return value */
 
     FUNC_ENTER_STATIC
 
-    /* Check arguments */
-    HDassert(f);
-    HDassert(H5F_addr_defined(addr));
+    /* check arguments */
+    HDassert(image);
     HDassert(udata);
 
     /* Allocate the B-tree node in memory */
@@ -134,53 +178,50 @@ H5B__load(H5F_t *f, hid_t dxpl_id, haddr_t addr, void *_udata)
     if(NULL == (bt->child = H5FL_SEQ_MALLOC(haddr_t, (size_t)shared->two_k)))
 	HGOTO_ERROR(H5E_BTREE, H5E_CANTALLOC, NULL, "can't allocate buffer for child addresses")
 
-    if(H5F_block_read(f, H5FD_MEM_BTREE, addr, shared->sizeof_rnode, dxpl_id, shared->page) < 0)
-	HGOTO_ERROR(H5E_BTREE, H5E_READERROR, NULL, "can't read B-tree node")
-
-    /* Set the pointer into the raw data buffer */
-    p = shared->page;
-
     /* magic number */
-    if(HDmemcmp(p, H5B_MAGIC, (size_t)H5_SIZEOF_MAGIC))
+    if(HDmemcmp(image, H5B_MAGIC, (size_t)H5_SIZEOF_MAGIC))
 	HGOTO_ERROR(H5E_BTREE, H5E_BADVALUE, NULL, "wrong B-tree signature")
-    p += 4;
+    image += H5_SIZEOF_MAGIC;
 
     /* node type and level */
-    if(*p++ != (uint8_t)udata->type->id)
+    if(*image++ != (uint8_t)udata->type->id)
 	HGOTO_ERROR(H5E_BTREE, H5E_CANTLOAD, NULL, "incorrect B-tree node type")
-    bt->level = *p++;
+    bt->level = *image++;
 
     /* entries used */
-    UINT16DECODE(p, bt->nchildren);
+    UINT16DECODE(image, bt->nchildren);
 
     /* Check if bt->nchildren is greater than two_k */
     if(bt->nchildren > shared->two_k)
         HGOTO_ERROR(H5E_BTREE, H5E_BADVALUE, NULL, "number of children is greater than maximum")
 
     /* sibling pointers */
-    H5F_addr_decode(udata->f, (const uint8_t **)&p, &(bt->left));
-    H5F_addr_decode(udata->f, (const uint8_t **)&p, &(bt->right));
+    H5F_addr_decode(udata->f, (const uint8_t **)&image, &(bt->left));
+    H5F_addr_decode(udata->f, (const uint8_t **)&image, &(bt->right));
 
     /* the child/key pairs */
     native = bt->native;
     for(u = 0; u < bt->nchildren; u++) {
         /* Decode native key value */
-        if((udata->type->decode)(shared, p, native) < 0)
+        if((udata->type->decode)(shared, image, native) < 0)
             HGOTO_ERROR(H5E_BTREE, H5E_CANTDECODE, NULL, "unable to decode key")
-        p += shared->sizeof_rkey;
+        image += shared->sizeof_rkey;
         native += udata->type->sizeof_nkey;
 
         /* Decode address value */
-        H5F_addr_decode(udata->f, (const uint8_t **)&p, bt->child + u);
+        H5F_addr_decode(udata->f, (const uint8_t **)&image, bt->child + u);
     } /* end for */
 
     /* Decode final key */
     if(bt->nchildren > 0) {
         /* Decode native key value */
-        if((udata->type->decode)(shared, p, native) < 0)
+        if((udata->type->decode)(shared, image, native) < 0)
             HGOTO_ERROR(H5E_BTREE, H5E_CANTDECODE, NULL, "unable to decode key")
     } /* end if */
 
+    /* Sanity check */
+    HDassert((size_t)((const uint8_t *)image - (const uint8_t *)_image) <= len);
+
     /* Set return value */
     ret_value = bt;
 
@@ -190,223 +231,151 @@ done:
             HDONE_ERROR(H5E_BTREE, H5E_CANTFREE, NULL, "unable to destroy B-tree node")
 
     FUNC_LEAVE_NOAPI(ret_value)
-} /* end H5B__load() */  /*lint !e818 Can't make udata a pointer to const */
+} /* end H5B__deserialize() */
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5B__flush
+ * Function:    H5B__image_len
  *
- * Purpose:	Flushes a dirty B-tree node to disk.
+ * Purpose:     Compute the size of the data structure on disk.
  *
  * Return:      Non-negative on success/Negative on failure
  *
- * Programmer:	Robb Matzke
- *		matzke@llnl.gov
- *		Jun 23 1997
+ * Programmer:  Quincey Koziol
+ *              koziol@hdfgroup.org
+ *              May 20, 2010
  *
  *-------------------------------------------------------------------------
  */
 static herr_t
-H5B__flush(H5F_t *f, hid_t dxpl_id, hbool_t destroy, haddr_t addr, H5B_t *bt, unsigned H5_ATTR_UNUSED * flags_ptr)
+H5B__image_len(const void *_thing, size_t *image_len,
+    hbool_t H5_ATTR_UNUSED *compressed_ptr, size_t H5_ATTR_UNUSED *compressed_image_len_ptr)
 {
+    const H5B_t *bt = (const H5B_t *)_thing;        /* Pointer to the B-tree node */
     H5B_shared_t *shared;       /* Pointer to shared B-tree info */
-    herr_t      ret_value = SUCCEED;    /* Return value */
 
-    FUNC_ENTER_STATIC
+    FUNC_ENTER_STATIC_NOERR
 
-    /* check arguments */
-    HDassert(f);
-    HDassert(H5F_addr_defined(addr));
+    /* Check arguments */
     HDassert(bt);
+    HDassert(image_len);
+
+    /* Get shared info for B-tree */
     shared = (H5B_shared_t *)H5UC_GET_OBJ(bt->rc_shared);
     HDassert(shared);
-    HDassert(shared->type);
-    HDassert(shared->type->encode);
 
-    if(bt->cache_info.is_dirty) {
-        uint8_t    *p;              /* Pointer into raw data buffer */
-        uint8_t    *native;         /* Pointer to native keys */
-        unsigned    u;              /* Local index variable */
-
-        p = shared->page;
-
-        /* magic number */
-        HDmemcpy(p, H5B_MAGIC, (size_t)H5_SIZEOF_MAGIC);
-        p += 4;
-
-        /* node type and level */
-        *p++ = (uint8_t)shared->type->id;
-        H5_CHECK_OVERFLOW(bt->level, unsigned, uint8_t);
-        *p++ = (uint8_t)bt->level;
-
-        /* entries used */
-        UINT16ENCODE(p, bt->nchildren);
-
-        /* sibling pointers */
-        H5F_addr_encode(f, &p, bt->left);
-        H5F_addr_encode(f, &p, bt->right);
-
-        /* child keys and pointers */
-        native = bt->native;
-        for(u = 0; u < bt->nchildren; ++u) {
-            /* encode the key */
-            if(shared->type->encode(shared, p, native) < 0)
-                HGOTO_ERROR(H5E_BTREE, H5E_CANTENCODE, FAIL, "unable to encode B-tree key")
-            p += shared->sizeof_rkey;
-            native += shared->type->sizeof_nkey;
-
-            /* encode the child address */
-            H5F_addr_encode(f, &p, bt->child[u]);
-        } /* end for */
-        if(bt->nchildren > 0) {
-            /* Encode the final key */
-            if(shared->type->encode(shared, p, native) < 0)
-                HGOTO_ERROR(H5E_BTREE, H5E_CANTENCODE, FAIL, "unable to encode B-tree key")
-        } /* end if */
-
-	/*
-         * Write the disk page.	We always write the header, but we don't
-         * bother writing data for the child entries that don't exist or
-         * for the final unchanged children.
-	 */
-	if(H5F_block_write(f, H5FD_MEM_BTREE, addr, shared->sizeof_rnode, dxpl_id, shared->page) < 0)
-	    HGOTO_ERROR(H5E_BTREE, H5E_CANTFLUSH, FAIL, "unable to save B-tree node to disk")
-
-	bt->cache_info.is_dirty = FALSE;
-    } /* end if */
-
-    if(destroy)
-        if(H5B__dest(f, bt) < 0)
-	    HGOTO_ERROR(H5E_BTREE, H5E_CANTFREE, FAIL, "unable to destroy B-tree node")
+    /* Set the image length size */
+    *image_len = shared->sizeof_rnode;
 
-done:
-    FUNC_LEAVE_NOAPI(ret_value)
-} /* end H5B__flush() */
+    FUNC_LEAVE_NOAPI(SUCCEED)
+} /* end H5B__image_len() */
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5B__dest
+ * Function:    H5B__serialize
  *
- * Purpose:	Destroys a B-tree node in memory.
+ * Purpose:     Serialize the data structure for writing to disk.
  *
- * Return:	Non-negative on success/Negative on failure
+ * Return:      Non-negative on success/Negative on failure
  *
- * Programmer:	Quincey Koziol
- *		koziol@ncsa.uiuc.edu
- *		Jan 15 2003
+ * Programmer:  Quincey Koziol
+ *              koziol@hdfgroup.org
+ *              Mar 24, 2008
  *
  *-------------------------------------------------------------------------
  */
 static herr_t
-H5B__dest(H5F_t *f, H5B_t *bt)
+H5B__serialize(const H5F_t *f, void *_image, size_t H5_ATTR_UNUSED len,
+    void *_thing)
 {
-    herr_t ret_value = SUCCEED;         /* Return value */
+    H5B_t *bt = (H5B_t *)_thing;        /* Pointer to the B-tree node */
+    H5B_shared_t *shared;               /* Pointer to shared B-tree info */
+    uint8_t    *image = (uint8_t *)_image;      /* Pointer into image buffer */
+    uint8_t    *native;                 /* Pointer to native keys */
+    unsigned    u;                      /* Local index counter */
+    herr_t      ret_value = SUCCEED;    /* Return value */
 
     FUNC_ENTER_STATIC
 
-    /*
-     * Check arguments.
-     */
-    HDassert(f);
+    /* check arguments */
+    HDassert(image);
     HDassert(bt);
     HDassert(bt->rc_shared);
+    shared = (H5B_shared_t *)H5UC_GET_OBJ(bt->rc_shared);
+    HDassert(shared);
+    HDassert(shared->type);
+    HDassert(shared->type->encode);
 
-    /* If we're going to free the space on disk, the address must be valid */
-    HDassert(!bt->cache_info.free_file_space_on_destroy || H5F_addr_defined(bt->cache_info.addr));
+    /* magic number */
+    HDmemcpy(image, H5B_MAGIC, (size_t)H5_SIZEOF_MAGIC);
+    image += 4;
 
-    /* Check for freeing file space for B-tree node */
-    if(bt->cache_info.free_file_space_on_destroy) {
-        H5B_shared_t *shared;               /* Pointer to shared B-tree info */
+    /* node type and level */
+    *image++ = (uint8_t)shared->type->id;
+    H5_CHECK_OVERFLOW(bt->level, unsigned, uint8_t);
+    *image++ = (uint8_t)bt->level;
 
-        /* Get the pointer to the shared B-tree info */
-        shared = (H5B_shared_t *)H5UC_GET_OBJ(bt->rc_shared);
-        HDassert(shared);
+    /* entries used */
+    UINT16ENCODE(image, bt->nchildren);
+
+    /* sibling pointers */
+    H5F_addr_encode(f, &image, bt->left);
+    H5F_addr_encode(f, &image, bt->right);
 
-        /* Release the space on disk */
-        /* (XXX: Nasty usage of internal DXPL value! -QAK) */
-        if(H5MF_xfree(f, H5FD_MEM_BTREE, H5AC_dxpl_id, bt->cache_info.addr, (hsize_t)shared->sizeof_rnode) < 0)
-            HGOTO_ERROR(H5E_BTREE, H5E_CANTFREE, FAIL, "unable to free B-tree node")
+    /* child keys and pointers */
+    native = bt->native;
+    for(u = 0; u < bt->nchildren; ++u) {
+        /* encode the key */
+        if(shared->type->encode(shared, image, native) < 0)
+            HGOTO_ERROR(H5E_BTREE, H5E_CANTENCODE, FAIL, "unable to encode B-tree key")
+        image += shared->sizeof_rkey;
+        native += shared->type->sizeof_nkey;
+
+        /* encode the child address */
+        H5F_addr_encode(f, &image, bt->child[u]);
+    } /* end for */
+    if(bt->nchildren > 0) {
+        /* Encode the final key */
+        if(shared->type->encode(shared, image, native) < 0)
+            HGOTO_ERROR(H5E_BTREE, H5E_CANTENCODE, FAIL, "unable to encode B-tree key")
     } /* end if */
 
-    /* Destroy B-tree node */
-    if(H5B__node_dest(bt) < 0)
-        HGOTO_ERROR(H5E_BTREE, H5E_CANTFREE, FAIL, "unable to destroy B-tree node")
+    /* Sanity check */
+    HDassert((size_t)((const uint8_t *)image - (const uint8_t *)_image) <= len);
 
 done:
     FUNC_LEAVE_NOAPI(ret_value)
-} /* end H5B__dest() */
+} /* end H5B__serialize() */
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5B__clear
+ * Function:    H5B__free_icr
  *
- * Purpose:	Mark a B-tree node in memory as non-dirty.
+ * Purpose:     Destroy/release an "in core representation" of a data structure
  *
- * Return:	Non-negative on success/Negative on failure
+ * Return:      Non-negative on success/Negative on failure
  *
- * Programmer:	Quincey Koziol
- *		koziol@ncsa.uiuc.edu
- *		Mar 20 2003
+ * Programmer:  Quincey Koziol
+ *              koziol@hdfgroup.org
+ *              Mar 26, 2008
  *
  *-------------------------------------------------------------------------
  */
 static herr_t
-H5B__clear(H5F_t *f, H5B_t *bt, hbool_t destroy)
+H5B__free_icr(void *thing)
 {
-    herr_t ret_value = SUCCEED;
+    herr_t      ret_value = SUCCEED;    /* Return value */
 
     FUNC_ENTER_STATIC
 
-    /*
-     * Check arguments.
-     */
-    HDassert(bt);
-
-    /* Reset the dirty flag.  */
-    bt->cache_info.is_dirty = FALSE;
+    /* Check arguments */
+    HDassert(thing);
 
-    if(destroy)
-        if(H5B__dest(f, bt) < 0)
-	    HGOTO_ERROR(H5E_BTREE, H5E_CANTFREE, FAIL, "unable to destroy B-tree node")
+    /* Destroy B-tree node */
+    if(H5B__node_dest((H5B_t *)thing) < 0)
+        HGOTO_ERROR(H5E_BTREE, H5E_CANTFREE, FAIL, "unable to destroy B-tree node")
 
 done:
     FUNC_LEAVE_NOAPI(ret_value)
-} /* end H5B__clear() */
-
-
-/*-------------------------------------------------------------------------
- * Function:	H5B__compute_size
- *
- * Purpose:	Compute the size in bytes of the specified instance of
- *		H5B_t on disk, and return it in *len_ptr.  On failure,
- *		the value of *len_ptr is undefined.
- *
- * Return:	Non-negative on success/Negative on failure
- *
- * Programmer:	John Mainzer
- *		5/13/04
- *
- *-------------------------------------------------------------------------
- */
-static herr_t
-H5B__compute_size(const H5F_t H5_ATTR_UNUSED *f, const H5B_t *bt, size_t *size_ptr)
-{
-    H5B_shared_t        *shared;        /* Pointer to shared B-tree info */
-
-    FUNC_ENTER_STATIC_NOERR
-
-    /* check arguments */
-    HDassert(f);
-    HDassert(bt);
-    HDassert(bt->rc_shared);
-    shared = (H5B_shared_t *)H5UC_GET_OBJ(bt->rc_shared);
-    HDassert(shared);
-    HDassert(shared->type);
-    HDassert(size_ptr);
-
-    /* Set size value */
-    *size_ptr = shared->sizeof_rnode;
-
-    FUNC_LEAVE_NOAPI(SUCCEED)
-} /* H5B__compute_size() */
+} /* end H5B__free_icr() */
 
diff --git a/src/H5Bdbg.c b/src/H5Bdbg.c
index 526a647..e6d54dc 100644
--- a/src/H5Bdbg.c
+++ b/src/H5Bdbg.c
@@ -89,7 +89,7 @@ H5B_debug(H5F_t *f, hid_t dxpl_id, haddr_t addr, FILE *stream, int indent, int f
     cache_udata.f = f;
     cache_udata.type = type;
     cache_udata.rc_shared = rc_shared;
-    if(NULL == (bt = (H5B_t *)H5AC_protect(f, dxpl_id, H5AC_BT, addr, &cache_udata, H5AC_READ)))
+    if(NULL == (bt = (H5B_t *)H5AC_protect(f, dxpl_id, H5AC_BT, addr, &cache_udata, H5AC__READ_ONLY_FLAG)))
 	HGOTO_ERROR(H5E_BTREE, H5E_CANTPROTECT, FAIL, "unable to load B-tree node")
 
     /*
@@ -206,7 +206,7 @@ H5B__assert(H5F_t *f, hid_t dxpl_id, haddr_t addr, const H5B_class_t *type, void
     cache_udata.f = f;
     cache_udata.type = type;
     cache_udata.rc_shared = rc_shared;
-    bt = (H5B_t *)H5AC_protect(f, dxpl_id, H5AC_BT, addr, &cache_udata, H5AC_READ);
+    bt = (H5B_t *)H5AC_protect(f, dxpl_id, H5AC_BT, addr, &cache_udata, H5AC__READ_ONLY_FLAG);
     HDassert(bt);
     shared = (H5B_shared_t *)H5UC_GET_OBJ(bt->rc_shared);
     HDassert(shared);
@@ -227,7 +227,7 @@ H5B__assert(H5F_t *f, hid_t dxpl_id, haddr_t addr, const H5B_class_t *type, void
      * test.
      */
     for(ncell = 0; cur; ncell++) {
-	bt = (H5B_t *)H5AC_protect(f, dxpl_id, H5AC_BT, cur->addr, &cache_udata, H5AC_READ);
+	bt = (H5B_t *)H5AC_protect(f, dxpl_id, H5AC_BT, cur->addr, &cache_udata, H5AC__READ_ONLY_FLAG);
 	HDassert(bt);
 
 	/* Check node header */
diff --git a/src/H5C.c b/src/H5C.c
index 5cdd65f..fc4e8a5 100644
--- a/src/H5C.c
+++ b/src/H5C.c
@@ -85,12 +85,23 @@
 #include "H5FDprivate.h"	/* File drivers				*/
 #include "H5FLprivate.h"	/* Free Lists                           */
 #include "H5Iprivate.h"		/* IDs			  		*/
+#include "H5MFprivate.h"	/* File memory management		*/
 #include "H5MMprivate.h"	/* Memory management			*/
 #include "H5Pprivate.h"         /* Property lists                       */
 #include "H5SLprivate.h"	/* Skip lists				*/
 
 
 /*
+ * Private macros.
+ */
+#if H5C_DO_MEMORY_SANITY_CHECKS
+#define H5C_IMAGE_EXTRA_SPACE 8
+#define H5C_IMAGE_SANITY_VALUE "DeadBeef"
+#else /* H5C_DO_MEMORY_SANITY_CHECKS */
+#define H5C_IMAGE_EXTRA_SPACE 0
+#endif /* H5C_DO_MEMORY_SANITY_CHECKS */
+
+/*
  * Private file-scope variables.
  */
 
@@ -103,27 +114,21 @@ H5FL_DEFINE_STATIC(H5C_t);
  */
 
 static herr_t H5C__auto_adjust_cache_size(H5F_t * f,
-                                          hid_t primary_dxpl_id,
-                                          hid_t secondary_dxpl_id,
-                                          hbool_t write_permitted,
-                                          hbool_t * first_flush_ptr);
+                                          hid_t dxpl_id,
+                                          hbool_t write_permitted);
 
 static herr_t H5C__autoadjust__ageout(H5F_t * f,
+                                      hid_t dxpl_id,
                                       double hit_rate,
                                       enum H5C_resize_status * status_ptr,
                                       size_t * new_max_cache_size_ptr,
-                                      hid_t primary_dxpl_id,
-                                      hid_t secondary_dxpl_id,
-                                      hbool_t write_permitted,
-                                      hbool_t * first_flush_ptr);
+                                      hbool_t write_permitted);
 
 static herr_t H5C__autoadjust__ageout__cycle_epoch_marker(H5C_t * cache_ptr);
 
 static herr_t H5C__autoadjust__ageout__evict_aged_out_entries(H5F_t * f,
-                                                    hid_t primary_dxpl_id,
-                                                    hid_t secondary_dxpl_id,
-                                                    hbool_t write_permitted,
-                                                    hbool_t * first_flush_ptr);
+                                                       hid_t dxpl_id,
+                                                       hbool_t write_permitted);
 
 static herr_t H5C__autoadjust__ageout__insert_new_marker(H5C_t * cache_ptr);
 
@@ -135,19 +140,16 @@ static herr_t H5C__flash_increase_cache_size(H5C_t * cache_ptr,
                                              size_t old_entry_size,
                                              size_t new_entry_size);
 
-static herr_t H5C_flush_single_entry(H5F_t *       	 f,
-                                     hid_t               primary_dxpl_id,
-                                     hid_t               secondary_dxpl_id,
-                                     const H5C_class_t * type_ptr,
-                                     haddr_t             addr,
-                                     unsigned            flags,
-                                     hbool_t *           first_flush_ptr,
-                                     hbool_t    del_entry_from_slist_on_destroy);
+static herr_t H5C_flush_single_entry(const H5F_t *	 f,
+                                     hid_t 		 dxpl_id,
+                                     haddr_t		 addr,
+                                     unsigned	         flags,
+                                     hbool_t del_entry_from_slist_on_destroy,
+                                     int64_t		*entry_size_change_ptr);
 
-static herr_t H5C_flush_invalidate_cache(H5F_t *  f,
-	                                 hid_t    primary_dxpl_id,
-				         hid_t    secondary_dxpl_id,
-					 unsigned flags);
+static herr_t H5C_flush_invalidate_cache(const H5F_t *  f,
+                                          hid_t    dxpl_id,
+			                  unsigned flags);
 
 static void * H5C_load_entry(H5F_t *             f,
                              hid_t               dxpl_id,
@@ -156,19 +158,16 @@ static void * H5C_load_entry(H5F_t *             f,
                              void *              udata);
 
 static herr_t H5C_make_space_in_cache(H5F_t * f,
-                                      hid_t   primary_dxpl_id,
-                                      hid_t   secondary_dxpl_id,
-                                      size_t  space_needed,
-                                      hbool_t write_permitted,
-                                      hbool_t * first_flush_ptr);
+                                      hid_t   dxpl_id,
+       	                              size_t  space_needed,
+                                      hbool_t write_permitted);
 
 static herr_t H5C_tag_entry(H5C_t * cache_ptr, 
                             H5C_cache_entry_t * entry_ptr,
                             hid_t dxpl_id);
 
 static herr_t H5C_flush_tagged_entries(H5F_t * f, 
-                                       hid_t primary_dxpl_id, 
-                                       hid_t secondary_dxpl_id, 
+                                       hid_t dxpl_id, 
                                        H5C_t * cache_ptr, 
                                        haddr_t tag);
 
@@ -176,20 +175,29 @@ static herr_t H5C_mark_tagged_entries(H5C_t * cache_ptr,
                                       haddr_t tag);
 
 static herr_t H5C_flush_marked_entries(H5F_t * f, 
-                                       hid_t primary_dxpl_id, 
-                                       hid_t secondary_dxpl_id, 
+                                       hid_t dxpl_id, 
                                        H5C_t * cache_ptr);
 
 #if H5C_DO_TAGGING_SANITY_CHECKS
 static herr_t H5C_verify_tag(int id, haddr_t tag);
 #endif
 
+#if H5C_DO_SLIST_SANITY_CHECKS
+static hbool_t H5C_entry_in_skip_list(H5C_t * cache_ptr, 
+                                      H5C_cache_entry_t *target_ptr);
+#endif /* H5C_DO_SLIST_SANITY_CHECKS */
+
 #if H5C_DO_EXTREME_SANITY_CHECKS
 static herr_t H5C_validate_lru_list(H5C_t * cache_ptr);
 static herr_t H5C_validate_pinned_entry_list(H5C_t * cache_ptr);
 static herr_t H5C_validate_protected_entry_list(H5C_t * cache_ptr);
 #endif /* H5C_DO_EXTREME_SANITY_CHECKS */
 
+#if 0 /* debugging routines */
+herr_t H5C_dump_cache(H5C_t * cache_ptr, const char *  cache_name);
+herr_t H5C_dump_cache_skip_list(H5C_t * cache_ptr, char * calling_fcn);
+#endif /* debugging routines */
+
 
 /****************************************************************************
  *
@@ -208,25 +216,53 @@ static herr_t H5C_validate_protected_entry_list(H5C_t * cache_ptr);
 
 #define H5C__EPOCH_MARKER_TYPE	H5C__MAX_NUM_TYPE_IDS
 
-static void *H5C_epoch_marker_load(H5F_t *f, hid_t dxpl_id, haddr_t addr,
-                                   void *udata);
-static herr_t H5C_epoch_marker_flush(H5F_t *f, hid_t dxpl_id, hbool_t dest,
-                                     haddr_t addr, void *thing,
-				     unsigned *flags_ptr);
-static herr_t H5C_epoch_marker_dest(H5F_t *f, void *thing);
-static herr_t H5C_epoch_marker_clear(H5F_t *f, void *thing, hbool_t dest);
-static herr_t H5C_epoch_marker_notify(H5C_notify_action_t action, void *thing);
-static herr_t H5C_epoch_marker_size(const H5F_t *f, const void *thing, size_t *size_ptr);
+static herr_t H5C__epoch_marker_get_load_size(const void *udata_ptr,
+		                            size_t *image_len_ptr);
+static void * H5C__epoch_marker_deserialize(const void * image_ptr,
+		                            size_t len,
+			                    void * udata,
+			                    hbool_t * dirty_ptr);
+static herr_t H5C__epoch_marker_image_len(const void * thing,
+		                          size_t *image_len_ptr,
+                                          hbool_t *compressed_ptr,
+                                          size_t *compressed_len_ptr);
+static herr_t H5C__epoch_marker_pre_serialize(const H5F_t *f,
+		                             hid_t dxpl_id,
+                                             void * thing,
+                                             haddr_t addr,
+		                             size_t len,
+					     size_t compressed_len,
+		                             haddr_t * new_addr_ptr,
+		                             size_t * new_len_ptr,
+					     size_t * new_compressed_len_ptr,
+		                             unsigned * flags_ptr);
+static herr_t H5C__epoch_marker_serialize(const H5F_t *f,
+		                          void * image_ptr,
+		                          size_t len,
+                                          void * thing);
+static herr_t H5C__epoch_marker_notify(H5C_notify_action_t action, void *thing);
+static herr_t H5C__epoch_marker_free_icr(void * thing);
+
+static herr_t H5C__epoch_marker_clear(const H5F_t *f, void * thing, 
+                                      hbool_t about_to_destroy);
+static herr_t H5C__epoch_marker_fsf_size(const void H5_ATTR_UNUSED * thing, 
+                                         size_t H5_ATTR_UNUSED * fsf_size_ptr);
 
 const H5C_class_t epoch_marker_class =
 {
-    /* id    = */ H5C__EPOCH_MARKER_TYPE,
-    /* load  = */ &H5C_epoch_marker_load,
-    /* flush = */ &H5C_epoch_marker_flush,
-    /* dest  = */ &H5C_epoch_marker_dest,
-    /* clear = */ &H5C_epoch_marker_clear,
-    /* notify = */&H5C_epoch_marker_notify,
-    /* size  = */ &H5C_epoch_marker_size
+    /* id               = */ H5C__EPOCH_MARKER_TYPE,
+    /* name             = */ "epoch marker",
+    /* mem_type         = */ H5FD_MEM_DEFAULT, /* value doesn't matter */
+    /* flags		= */ H5AC__CLASS_NO_FLAGS_SET,
+    /* get_load_size    = */ H5C__epoch_marker_get_load_size,
+    /* deserialize      = */ H5C__epoch_marker_deserialize,
+    /* image_len        = */ H5C__epoch_marker_image_len,
+    /* pre_serialize    = */ H5C__epoch_marker_pre_serialize,
+    /* serialize        = */ H5C__epoch_marker_serialize,
+    /* notify           = */ H5C__epoch_marker_notify,
+    /* free_icr         = */ H5C__epoch_marker_free_icr,
+    /* clear            = */ H5C__epoch_marker_clear,
+    /* fsf_size         = */ H5C__epoch_marker_fsf_size,
 };
 
 
@@ -239,107 +275,114 @@ const H5C_class_t epoch_marker_class =
  *                                                     JRM - 11/16/04
  *
  ***************************************************************************/
-
-static void *
-H5C_epoch_marker_load(H5F_t H5_ATTR_UNUSED * f,
-                      hid_t H5_ATTR_UNUSED dxpl_id,
-                      haddr_t H5_ATTR_UNUSED addr,
-                      void H5_ATTR_UNUSED * udata)
+static herr_t
+H5C__epoch_marker_get_load_size(const void H5_ATTR_UNUSED *udata_ptr,
+    size_t H5_ATTR_UNUSED *image_len_ptr)
 {
-    void * ret_value = NULL;      /* Return value */
+    FUNC_ENTER_STATIC_NOERR /* Yes, even though this pushes an error on the stack */
 
-    FUNC_ENTER_NOAPI_NOINIT
+    HERROR(H5E_CACHE, H5E_SYSTEM, "called unreachable fcn.");
 
-    HGOTO_ERROR(H5E_CACHE, H5E_SYSTEM, NULL, "called unreachable fcn.")
+    FUNC_LEAVE_NOAPI(FAIL)
+} /* end H5C__epoch_marker_get_load_size() */
 
-done:
+
+static void *
+H5C__epoch_marker_deserialize(const void H5_ATTR_UNUSED * image_ptr, size_t H5_ATTR_UNUSED len,
+    void H5_ATTR_UNUSED * udata, hbool_t H5_ATTR_UNUSED * dirty_ptr)
+{
+    FUNC_ENTER_STATIC_NOERR /* Yes, even though this pushes an error on the stack */
 
-    FUNC_LEAVE_NOAPI(ret_value)
-}
+    HERROR(H5E_CACHE, H5E_SYSTEM, "called unreachable fcn.");
 
+    FUNC_LEAVE_NOAPI(NULL)
+} /* end H5C__epoch_marker_deserialize() */
 
 
 static herr_t
-H5C_epoch_marker_flush(H5F_t H5_ATTR_UNUSED *f,
-                       hid_t H5_ATTR_UNUSED dxpl_id,
-                       hbool_t H5_ATTR_UNUSED dest,
-                       haddr_t H5_ATTR_UNUSED addr,
-                       void H5_ATTR_UNUSED *thing,
-		       unsigned H5_ATTR_UNUSED * flags_ptr)
+H5C__epoch_marker_image_len(const void H5_ATTR_UNUSED *thing,
+    size_t H5_ATTR_UNUSED *image_len_ptr, hbool_t H5_ATTR_UNUSED *compressed_ptr,
+    size_t H5_ATTR_UNUSED *compressed_len_ptr)
 {
-    herr_t ret_value = FAIL;      /* Return value */
+    FUNC_ENTER_STATIC_NOERR /* Yes, even though this pushes an error on the stack */
 
-    FUNC_ENTER_NOAPI_NOINIT
+    HERROR(H5E_CACHE, H5E_SYSTEM, "called unreachable fcn.");
 
-    HGOTO_ERROR(H5E_CACHE, H5E_SYSTEM, FAIL, "called unreachable fcn.")
+    FUNC_LEAVE_NOAPI(FAIL)
+} /* end H5C__epoch_marker_image_len() */
 
-done:
+
+static herr_t
+H5C__epoch_marker_pre_serialize(const H5F_t H5_ATTR_UNUSED *f, hid_t H5_ATTR_UNUSED dxpl_id,
+    void H5_ATTR_UNUSED *thing, haddr_t H5_ATTR_UNUSED addr, size_t H5_ATTR_UNUSED len,
+    size_t H5_ATTR_UNUSED compressed_len, haddr_t H5_ATTR_UNUSED *new_addr_ptr, 
+    size_t H5_ATTR_UNUSED *new_len_ptr, size_t H5_ATTR_UNUSED *new_compressed_len_ptr,
+    unsigned H5_ATTR_UNUSED *flags_ptr)
+{
+    FUNC_ENTER_STATIC_NOERR /* Yes, even though this pushes an error on the stack */
 
-    FUNC_LEAVE_NOAPI(ret_value)
-}
+    HERROR(H5E_CACHE, H5E_SYSTEM, "called unreachable fcn.");
 
+    FUNC_LEAVE_NOAPI(FAIL)
+} /* end H5C__epoch_marker_pre_serialize() */
 
 
 static herr_t
-H5C_epoch_marker_dest(H5F_t H5_ATTR_UNUSED * f,
-                      void H5_ATTR_UNUSED * thing)
+H5C__epoch_marker_serialize(const H5F_t H5_ATTR_UNUSED *f, void H5_ATTR_UNUSED *image_ptr,
+    size_t H5_ATTR_UNUSED len, void H5_ATTR_UNUSED *thing)
 {
-    herr_t ret_value = FAIL;      /* Return value */
-
-    FUNC_ENTER_NOAPI_NOINIT
+    FUNC_ENTER_STATIC_NOERR /* Yes, even though this pushes an error on the stack */
 
-    HGOTO_ERROR(H5E_CACHE, H5E_SYSTEM, FAIL, "called unreachable fcn.")
+    HERROR(H5E_CACHE, H5E_SYSTEM, "called unreachable fcn.");
 
-done:
-
-    FUNC_LEAVE_NOAPI(ret_value)
-}
+    FUNC_LEAVE_NOAPI(FAIL)
+} /* end H5C__epoch_marker_serialize() */
 
+
 static herr_t
-H5C_epoch_marker_clear(H5F_t H5_ATTR_UNUSED * f,
-                       void H5_ATTR_UNUSED * thing,
-                       hbool_t H5_ATTR_UNUSED dest)
+H5C__epoch_marker_notify(H5C_notify_action_t H5_ATTR_UNUSED action,
+                       void H5_ATTR_UNUSED * thing)
 {
-    herr_t ret_value = FAIL;      /* Return value */
-
-    FUNC_ENTER_NOAPI_NOINIT
+    FUNC_ENTER_STATIC_NOERR /* Yes, even though this pushes an error on the stack */
 
-    HGOTO_ERROR(H5E_CACHE, H5E_SYSTEM, FAIL, "called unreachable fcn.")
+    HERROR(H5E_CACHE, H5E_SYSTEM, "called unreachable fcn.");
 
-done:
-
-    FUNC_LEAVE_NOAPI(ret_value)
-}
+    FUNC_LEAVE_NOAPI(FAIL)
+} /* end H5C__epoch_marker_notify() */
 
+
 static herr_t
-H5C_epoch_marker_notify(H5C_notify_action_t H5_ATTR_UNUSED action,
-                       void H5_ATTR_UNUSED * thing)
+H5C__epoch_marker_free_icr(void H5_ATTR_UNUSED * thing)
 {
-    herr_t ret_value = FAIL;      /* Return value */
+    FUNC_ENTER_STATIC_NOERR /* Yes, even though this pushes an error on the stack */
 
-    FUNC_ENTER_NOAPI_NOINIT
+    HERROR(H5E_CACHE, H5E_SYSTEM, "called unreachable fcn.");
 
-    HGOTO_ERROR(H5E_CACHE, H5E_SYSTEM, FAIL, "called unreachable fcn.")
+    FUNC_LEAVE_NOAPI(FAIL)
+} /* end H5C__epoch_marker_free_icr() */
 
-done:
-    FUNC_LEAVE_NOAPI(ret_value)
-}
-
-static herr_t
-H5C_epoch_marker_size(const H5F_t H5_ATTR_UNUSED * f,
-                      const void H5_ATTR_UNUSED * thing,
-                      size_t H5_ATTR_UNUSED * size_ptr)
+
+static herr_t 
+H5C__epoch_marker_clear(const H5F_t H5_ATTR_UNUSED *f, void H5_ATTR_UNUSED * thing, hbool_t H5_ATTR_UNUSED about_to_destroy)
 {
-    herr_t ret_value = FAIL;      /* Return value */
+    FUNC_ENTER_STATIC_NOERR /* Yes, even though this pushes an error on the stack */
 
-    FUNC_ENTER_NOAPI_NOINIT
+    HERROR(H5E_CACHE, H5E_SYSTEM, "called unreachable fcn.");
 
-    HGOTO_ERROR(H5E_CACHE, H5E_SYSTEM, FAIL, "called unreachable fcn.")
+    FUNC_LEAVE_NOAPI(FAIL)
+} /* end H5C__epoch_marker_clear() */
 
-done:
+
+static herr_t 
+H5C__epoch_marker_fsf_size(const void H5_ATTR_UNUSED * thing, size_t H5_ATTR_UNUSED *fsf_size_ptr)
+{
+    FUNC_ENTER_STATIC_NOERR /* Yes, even though this pushes an error on the stack */
+
+    HERROR(H5E_CACHE, H5E_SYSTEM, "called unreachable fcn.");
+
+    FUNC_LEAVE_NOAPI(FAIL)
+} /* end H5C__epoch_marker_fsf_size() */
 
-    FUNC_LEAVE_NOAPI(ret_value)
-}
 
 
 /*-------------------------------------------------------------------------
@@ -423,21 +466,46 @@ done:
  * Programmer:  John Mainzer
  *              3/17/10
  *
+ * Changes:     Ported code to detect next entry status changes as the 
+ *              the result of a flush from the serial code in the scan of 
+ *              the LRU.  Also added code to detect and adapt to the 
+ *              removal from the cache of the next entry in the scan of 
+ *		the LRU.
+ *
+ *		Note that at present, all of these changes should not 
+ *		be required as the operations on entries as they are 
+ *		flushed that can cause these condiditions are not premitted
+ *		in the parallel case.  However, Quincey indicates that 
+ *		this may change, and thus has requested the modification.
+ *
+ *		Note the assert(FALSE) in the if statement whose body 
+ *		restarts the scan of the LRU.  As the body of the if 
+ *		statement should be unreachable, it should never be 
+ *		triggered until the constraints on the parallel case 
+ *		are relaxed.  Please remove the assertion at that time.
+ *
+ *		Also added warning on the Pinned Entry List scan, as it
+ *		is potentially subject to the same issue.  As there is 
+ *		no cognate of this scan in the serial code, I don't have
+ *		a fix to port to it.
+ *
+ *						JRM -- 4/10/19
+ *		
  *-------------------------------------------------------------------------
  */
 #ifdef H5_HAVE_PARALLEL
 #define H5C_APPLY_CANDIDATE_LIST__DEBUG 0
 herr_t
 H5C_apply_candidate_list(H5F_t * f,
-                         hid_t primary_dxpl_id,
-                         hid_t secondary_dxpl_id,
+                         hid_t dxpl_id,
                          H5C_t * cache_ptr,
                          int num_candidates,
                          haddr_t * candidates_list_ptr,
                          int mpi_rank,
                          int mpi_size)
 {
-    hbool_t             first_flush = FALSE;
+    hbool_t		restart_scan;
+    hbool_t		prev_is_dirty;
     int                 i;
     int			m;
     int			n;
@@ -457,6 +525,7 @@ H5C_apply_candidate_list(H5F_t * f,
     int               * candidate_assignment_table = NULL;
     haddr_t		addr;
     H5C_cache_entry_t *	clear_ptr = NULL;
+    H5C_cache_entry_t *	next_ptr = NULL;
     H5C_cache_entry_t *	entry_ptr = NULL;
     H5C_cache_entry_t *	flush_ptr = NULL;
     H5C_cache_entry_t * delayed_ptr = NULL;
@@ -634,16 +703,29 @@ H5C_apply_candidate_list(H5F_t * f,
      * should be reworked to account for additional cases.
      * ===================================================================== */
 
+    HDassert(entries_to_flush >= 0);
+
+    restart_scan = FALSE;
     entries_examined = 0;
     initial_list_len = cache_ptr->LRU_list_len;
     entry_ptr = cache_ptr->LRU_tail_ptr;
 
     /* Examine each entry in the LRU list */
-    while((entry_ptr != NULL) && (entries_examined <= initial_list_len) &&
-            ((entries_cleared + entries_flushed) < num_candidates)) {
+    while ( ( entry_ptr != NULL ) 
+            && 
+            ( entries_examined <= (entries_to_flush + 1) * initial_list_len ) 
+            &&
+            ( (entries_cleared + entries_flushed) < num_candidates ) ) {
+
+        if ( entry_ptr->prev != NULL )
+            prev_is_dirty = entry_ptr->prev->is_dirty;
 
         /* If this process needs to clear this entry. */
         if(entry_ptr->clear_on_unprotect) {
+
+            HDassert(entry_ptr->is_dirty);
+
+            next_ptr = entry_ptr->next; 
             entry_ptr->clear_on_unprotect = FALSE;
             clear_ptr = entry_ptr;
             entry_ptr = entry_ptr->prev;
@@ -654,20 +736,26 @@ H5C_apply_candidate_list(H5F_t * f,
               (long long)clear_ptr->addr);
 #endif /* H5C_APPLY_CANDIDATE_LIST__DEBUG */
 
+	    /* No need to check for the next entry in the scan being 
+             * removed from the cache, as this call to H5C_flush_single_entry()
+             * will not call either the pre_serialize or serialize callbacks.
+             */
+
             if(H5C_flush_single_entry(f,
-                                      primary_dxpl_id,
-                                      secondary_dxpl_id,
-                                      clear_ptr->type,
+                                      dxpl_id,
                                       clear_ptr->addr,
                                       H5C__FLUSH_CLEAR_ONLY_FLAG,
-                                      &first_flush,
-                                      TRUE) < 0)
+                                      TRUE, 
+                                      NULL) < 0)
                 HGOTO_ERROR(H5E_CACHE, H5E_SYSTEM, FAIL, "Can't clear entry.")
         } /* end if */
 
         /* Else, if this process needs to flush this entry. */
         else if (entry_ptr->flush_immediately) {
 
+	    HDassert(entry_ptr->is_dirty);
+
+            next_ptr = entry_ptr->next; 
             entry_ptr->flush_immediately = FALSE;
             flush_ptr = entry_ptr;
             entry_ptr = entry_ptr->prev;
@@ -678,22 +766,94 @@ H5C_apply_candidate_list(H5F_t * f,
               (long long)flush_ptr->addr);
 #endif /* H5C_APPLY_CANDIDATE_LIST__DEBUG */
 
+            /* reset entries_removed_counter and
+             * last_entry_removed_ptr prior to the call to
+             * H5C_flush_single_entry() so that we can spot
+             * unexpected removals of entries from the cache,
+             * and set the restart_scan flag if proceeding
+             * would be likely to cause us to scan an entry
+             * that is no longer in the cache.
+             *
+             * Note that as of this writing (April 2015) this 
+             * case cannot occur in the parallel case.  However 
+             * Quincey is making noises about changing this, hence 
+             * the insertion of this test.
+             *
+             * Note also that there is no test code to verify 
+             * that this code actually works (although similar code
+             * in the serial version exists and is tested).  
+             * 
+             * Implementing a test will likely require implementing
+             * flush op like facilities in the parallel tests.  At
+             * a guess this will not be terribly painful, but it 
+             * will take a bit of time.
+             */
+            cache_ptr->entries_removed_counter = 0;
+            cache_ptr->last_entry_removed_ptr  = NULL;
+
             if(H5C_flush_single_entry(f,
-                                      primary_dxpl_id,
-                                      secondary_dxpl_id,
-                                      flush_ptr->type,
+                                      dxpl_id,
                                       flush_ptr->addr,
                                       H5C__NO_FLAGS_SET,
-                                      &first_flush,
-                                      TRUE) < 0)
+                                      TRUE,
+                                      NULL) < 0)
                 HGOTO_ERROR(H5E_CACHE, H5E_SYSTEM, FAIL, "Can't flush entry.")
+
+            if ( ( cache_ptr->entries_removed_counter > 1 ) ||
+                 ( cache_ptr->last_entry_removed_ptr == entry_ptr ) )
+
+                restart_scan = TRUE;
+
         } /* end else-if */
 
         /* Otherwise, no action to be taken on this entry. Grab the next. */
         else {
             entry_ptr = entry_ptr->prev;
+
+            if ( entry_ptr != NULL )
+                next_ptr = entry_ptr->next; 
+
         } /* end else */
 
+        if ( ( entry_ptr != NULL ) 
+             &&
+             ( ( restart_scan )
+               ||
+               ( entry_ptr->is_dirty != prev_is_dirty )
+               ||
+               ( entry_ptr->next != next_ptr )
+               ||
+               ( entry_ptr->is_protected )
+               ||
+               ( entry_ptr->is_pinned ) 
+             ) 
+           ) {
+
+            /* something has happened to the LRU -- start over
+             * from the tail.
+             *
+             * Recall that this code should be un-reachable at present,
+             * as all the operations by entries on flush that could cause
+             * it to be reachable are disallowed in the parallel case at
+             * present.  Hence the following assertion which should be 
+             * removed if the above changes.
+             */
+
+	    HDassert( ! restart_scan );
+            HDassert( entry_ptr->is_dirty == prev_is_dirty );
+            HDassert( entry_ptr->next == next_ptr );
+            HDassert( ! entry_ptr->is_protected );
+            HDassert( ! entry_ptr->is_pinned );
+
+            HDassert(FALSE); /* see comment above */
+
+            restart_scan = FALSE;
+            entry_ptr = cache_ptr->LRU_tail_ptr;
+/* 
+	    H5C__UPDATE_STATS_FOR_LRU_SCAN_RESTART(cache_ptr)
+*/
+        }
+
         entries_examined++;
     } /* end while */
 
@@ -705,6 +865,30 @@ H5C_apply_candidate_list(H5F_t * f,
 
     /* It is also possible that some of the cleared entries are on the
      * pinned list.  Must scan that also.
+     *
+     * WARNING:
+     *
+     *	As we now allow unpinning, and removal of other entries as a side 
+     *  effect of flushing an entry, it is possible that the next entry
+     *  in a PEL scan could either be no longer pinned, or no longer in
+     *  the cache by the time we get to it.
+     *
+     *  At present, this is not possible in this case, as we disallow such
+     *  operations in the parallel version of the library.  However, Quincey
+     *  has been making noises about relaxing this.  If and when he does,
+     *  we have a potential problem here.
+     *
+     *  The same issue exists in the serial cache, and there are tests 
+     *  to detect this problem when it occurs, and adjust to it.  As seen
+     *  above in the LRU scan, I have ported such tests to the parallel 
+     *  code where a close cognate exists in the serial code.  
+     *
+     *  I haven't done so here, as there are no PEL scans where the problem
+     *  can occur in the serial code.  Needless to say, this will have to 
+     *  be repaired if the constraints on pre_serialize and serialize 
+     *  callbacks are relaxed in the parallel version of the metadata cache.
+     *
+     *						JRM -- 4/1/15
      */
 
 #if H5C_APPLY_CANDIDATE_LIST__DEBUG
@@ -772,14 +956,12 @@ H5C_apply_candidate_list(H5F_t * f,
 #endif /* H5C_APPLY_CANDIDATE_LIST__DEBUG */
 
                 if(H5C_flush_single_entry(f,
-                                          primary_dxpl_id,
-                                          secondary_dxpl_id,
-                                          clear_ptr->type,
-                                          clear_ptr->addr,
-                                          H5C__FLUSH_CLEAR_ONLY_FLAG,
-                                          &first_flush,
-                                          TRUE) < 0)
-                    HGOTO_ERROR(H5E_CACHE, H5E_SYSTEM, FAIL, "Can't clear entry.")
+                                      dxpl_id,
+                                      clear_ptr->addr,
+                                      H5C__FLUSH_CLEAR_ONLY_FLAG,
+                                      TRUE,
+                                      NULL) < 0)
+                HGOTO_ERROR(H5E_CACHE, H5E_SYSTEM, FAIL, "Can't clear entry.")
             } /* end else-if */
 
             /* Else, if this process needs to independently flush this entry. */
@@ -795,14 +977,12 @@ H5C_apply_candidate_list(H5F_t * f,
 #endif /* H5C_APPLY_CANDIDATE_LIST__DEBUG */
 
                 if(H5C_flush_single_entry(f,
-                                          primary_dxpl_id,
-                                          secondary_dxpl_id,
-                                          flush_ptr->type,
-                                          flush_ptr->addr,
-                                          H5C__NO_FLAGS_SET,
-                                          &first_flush,
-                                          TRUE) < 0)
-                    HGOTO_ERROR(H5E_CACHE, H5E_SYSTEM, FAIL, "Can't flush entry.")
+                                      dxpl_id,
+                                      flush_ptr->addr,
+                                      H5C__NO_FLAGS_SET,
+                                      TRUE,
+                                      NULL) < 0)
+                HGOTO_ERROR(H5E_CACHE, H5E_SYSTEM, FAIL, "Can't clear entry.")
             } /* end else-if */
         } /* end if */
 
@@ -843,13 +1023,11 @@ H5C_apply_candidate_list(H5F_t * f,
         } /* end if */
 
         if(H5C_flush_single_entry(f,
-                                  primary_dxpl_id,
-                                  secondary_dxpl_id,
-                                  delayed_ptr->type,
+                                  dxpl_id,
                                   delayed_ptr->addr,
                                   H5C__NO_FLAGS_SET,
-                                  &first_flush,
-                                  TRUE) < 0)
+                                  TRUE,
+                                  NULL) < 0)
             HGOTO_ERROR(H5E_CACHE, H5E_SYSTEM, FAIL,
                         "Can't flush entry collectively.")
 
@@ -1184,6 +1362,9 @@ H5C_create(size_t		      max_cache_size,
     /* Tagging Field Initializations */
     cache_ptr->ignore_tags                      = FALSE;
 
+    cache_ptr->slist_changed			= FALSE;
+    cache_ptr->slist_change_in_pre_serialize	= FALSE;
+    cache_ptr->slist_change_in_serialize	= FALSE;
     cache_ptr->slist_len			= 0;
     cache_ptr->slist_size			= (size_t)0;
 
@@ -1197,6 +1378,9 @@ H5C_create(size_t		      max_cache_size,
         (cache_ptr->index)[i] = NULL;
     }
 
+    cache_ptr->entries_removed_counter		= 0;
+    cache_ptr->last_entry_removed_ptr		= NULL;
+
     cache_ptr->pl_len				= 0;
     cache_ptr->pl_size				= (size_t)0;
     cache_ptr->pl_head_ptr			= NULL;
@@ -1271,11 +1455,8 @@ H5C_create(size_t		      max_cache_size,
     /* Set non-zero/FALSE/NULL fields for epoch markers */
     for ( i = 0; i < H5C__MAX_EPOCH_MARKERS; i++ )
     {
-        (cache_ptr->epoch_marker_active)[i]		 = FALSE;
-#ifndef NDEBUG
         ((cache_ptr->epoch_markers)[i]).magic		 =
 					       H5C__H5C_CACHE_ENTRY_T_MAGIC;
-#endif /* NDEBUG */
         ((cache_ptr->epoch_markers)[i]).addr		 = (haddr_t)i;
         ((cache_ptr->epoch_markers)[i]).type		 = &epoch_marker_class;
     }
@@ -1530,9 +1711,7 @@ H5C_def_auto_resize_rpt_fcn(H5C_t * cache_ptr,
  *-------------------------------------------------------------------------
  */
 herr_t
-H5C_dest(H5F_t * f,
-         hid_t	 primary_dxpl_id,
-         hid_t	 secondary_dxpl_id)
+H5C_dest(H5F_t * f, hid_t dxpl_id)
 {
     H5C_t * cache_ptr = f->shared->cache;
     herr_t ret_value = SUCCEED;      /* Return value */
@@ -1544,8 +1723,7 @@ H5C_dest(H5F_t * f,
     HDassert(cache_ptr->magic == H5C__H5C_T_MAGIC);
 
     /* Flush and invalidate all cache entries */
-    if(H5C_flush_invalidate_cache(f, primary_dxpl_id, secondary_dxpl_id,
-                H5C__NO_FLAGS_SET) < 0 )
+    if(H5C_flush_invalidate_cache(f, dxpl_id, H5C__NO_FLAGS_SET) < 0 )
         HGOTO_ERROR(H5E_CACHE, H5E_CANTFLUSH, FAIL, "unable to flush cache")
 
     if(cache_ptr->slist_ptr != NULL) {
@@ -1570,7 +1748,9 @@ H5C_dest(H5F_t * f,
 #endif /* H5C_DO_SANITY_CHECKS */
 #endif /* NDEBUG */
 
+#ifndef NDEBUG
     cache_ptr->magic = 0;
+#endif /* NDEBUG */
 
     cache_ptr = H5FL_FREE(H5C_t, cache_ptr);
 
@@ -1595,17 +1775,16 @@ done:
  *-------------------------------------------------------------------------
  */
 herr_t
-H5C_expunge_entry(H5F_t *             f,
-                  hid_t               primary_dxpl_id,
-                  hid_t               secondary_dxpl_id,
-                  const H5C_class_t * type,
-                  haddr_t 	      addr,
-                  unsigned 	      flags)
+H5C_expunge_entry(H5F_t *f, hid_t dxpl_id, const H5C_class_t *type,
+    haddr_t addr, unsigned flags)
 {
     H5C_t *		cache_ptr;
-    herr_t		result;
-    hbool_t		first_flush = TRUE;
     H5C_cache_entry_t *	entry_ptr = NULL;
+    unsigned            flush_flags = (H5C__FLUSH_INVALIDATE_FLAG | H5C__FLUSH_CLEAR_ONLY_FLAG);
+#if H5C_DO_SANITY_CHECKS
+    hbool_t entry_was_dirty;
+    hsize_t entry_size;
+#endif /* H5C_DO_SANITY_CHECKS */
     herr_t		ret_value = SUCCEED;      /* Return value */
 
     FUNC_ENTER_NOAPI(FAIL)
@@ -1616,8 +1795,6 @@ H5C_expunge_entry(H5F_t *             f,
     HDassert(cache_ptr);
     HDassert(cache_ptr->magic == H5C__H5C_T_MAGIC);
     HDassert(type);
-    HDassert(type->clear);
-    HDassert(type->dest);
     HDassert(H5F_addr_defined(addr));
 
 #if H5C_DO_EXTREME_SANITY_CHECKS
@@ -1641,27 +1818,34 @@ H5C_expunge_entry(H5F_t *             f,
     if(entry_ptr->is_pinned)
         HGOTO_ERROR(H5E_CACHE, H5E_CANTEXPUNGE, FAIL, "Target entry is pinned.")
 
-    /* Pass along 'free file space' flag to cache client */
-    entry_ptr->free_file_space_on_destroy = ( (flags & H5C__FREE_FILE_SPACE_FLAG) != 0 );
-
     /* If we get this far, call H5C_flush_single_entry() with the
      * H5C__FLUSH_INVALIDATE_FLAG and the H5C__FLUSH_CLEAR_ONLY_FLAG.
      * This will clear the entry, and then delete it from the cache.
      */
-    result = H5C_flush_single_entry(f,
-                                    primary_dxpl_id,
-                                    secondary_dxpl_id,
-                                    entry_ptr->type,
-                                    entry_ptr->addr,
-                                    H5C__FLUSH_INVALIDATE_FLAG | H5C__FLUSH_CLEAR_ONLY_FLAG,
-                                    &first_flush,
-                                    TRUE);
 
-    if ( result < 0 ) {
+    /* Pass along 'free file space' flag to  cache client.  */
+    flush_flags |= (flags & H5C__FREE_FILE_SPACE_FLAG);
 
-        HGOTO_ERROR(H5E_CACHE, H5E_CANTEXPUNGE, FAIL, \
-                    "H5C_flush_single_entry() failed.")
+#if H5C_DO_SANITY_CHECKS
+    entry_was_dirty = entry_ptr->is_dirty;
+    entry_size      = entry_ptr->size;
+#endif /* H5C_DO_EXTREME_SANITY_CHECKS */
+
+    if(H5C_flush_single_entry(f, dxpl_id, entry_ptr->addr, flush_flags, TRUE, NULL) < 0)
+        HGOTO_ERROR(H5E_CACHE, H5E_CANTEXPUNGE, FAIL, "H5C_flush_single_entry() failed.")
+
+#if H5C_DO_SANITY_CHECKS
+    if ( entry_was_dirty )
+    {
+        /* we have just removed an entry from the skip list.  Thus 
+         * we must touch up cache_ptr->slist_len_increase and
+         * cache_ptr->slist_size_increase to keep from skewing
+         * the sanity checks on flushes.
+         */
+        cache_ptr->slist_len_increase -= 1;
+        cache_ptr->slist_size_increase -= (int64_t)(entry_size);
     }
+#endif /* H5C_DO_SANITY_CHECKS */
 
 done:
 #if H5C_DO_EXTREME_SANITY_CHECKS
@@ -1698,10 +1882,24 @@ done:
  * Programmer:  John Mainzer
  *		6/2/04
  *
+ * Changes:	Modified function to test for slist chamges in 
+ *		pre_serialize and serialize callbacks, and re-start
+ *		scans through the slist when such changes occur.
+ *
+ *		This has been a potential problem for some time,
+ *		and there has been code in this function to deal 
+ *		with elements of this issue.  However the shift 
+ *		to the V3 cache in combination with the activities
+ *		of some of the cache clients (in particular the 
+ *		free space manager and the fractal heap) have
+ *		made this re-work necessary.
+ *
+ *						JRM -- 12/13/14
+ *
  *-------------------------------------------------------------------------
  */
 herr_t
-H5C_flush_cache(H5F_t *f, hid_t primary_dxpl_id, hid_t secondary_dxpl_id, unsigned flags)
+H5C_flush_cache(H5F_t *f, hid_t dxpl_id, unsigned flags)
 {
     H5C_t * cache_ptr = f->shared->cache;
     herr_t              status;
@@ -1709,9 +1907,9 @@ H5C_flush_cache(H5F_t *f, hid_t primary_dxpl_id, hid_t secondary_dxpl_id, unsign
     hbool_t             destroy;
     hbool_t		flushed_entries_last_pass;
     hbool_t		flush_marked_entries;
-    hbool_t		first_flush = TRUE;
     hbool_t		ignore_protected;
     hbool_t		tried_to_flush_protected_entry = FALSE;
+    hbool_t		restart_slist_scan;
     int32_t		passes = 0;
     int32_t		protected_entries = 0;
     H5SL_node_t * 	node_ptr = NULL;
@@ -1722,6 +1920,10 @@ H5C_flush_cache(H5F_t *f, hid_t primary_dxpl_id, hid_t secondary_dxpl_id, unsign
     int64_t		flushed_entries_size = 0;
     int64_t		initial_slist_len = 0;
     size_t              initial_slist_size = 0;
+    int64_t		entry_size_change;
+    int64_t	      * entry_size_change_ptr = &entry_size_change;
+#else /* H5C_DO_SANITY_CHECKS */
+    int64_t           * entry_size_change_ptr = NULL;
 #endif /* H5C_DO_SANITY_CHECKS */
 
     FUNC_ENTER_NOAPI(FAIL)
@@ -1758,10 +1960,7 @@ H5C_flush_cache(H5F_t *f, hid_t primary_dxpl_id, hid_t secondary_dxpl_id, unsign
 
     if ( destroy ) {
 
-        status = H5C_flush_invalidate_cache(f,
-			                    primary_dxpl_id,
-					    secondary_dxpl_id,
-					    flags);
+        status = H5C_flush_invalidate_cache(f, dxpl_id, flags);
 
         if ( status < 0 ) {
 
@@ -1780,6 +1979,18 @@ H5C_flush_cache(H5F_t *f, hid_t primary_dxpl_id, hid_t secondary_dxpl_id, unsign
 
 	flushed_entries_last_pass = TRUE;
 
+        /* set the cache_ptr->slist_change_in_pre_serialize and
+	 * cache_ptr->slist_change_in_serialize to false.
+         *
+         * These flags are set to TRUE by H5C_flush_single_entry if the 
+ 	 * slist is modified by a pre_serialize or serialize call respectively.
+         * H5C_flush_cache uses these flags to detect any modifications
+         * to the slist that might corrupt the scan of the slist -- and 
+	 * restart the scan in this event.
+         */
+        cache_ptr->slist_change_in_pre_serialize = FALSE;
+        cache_ptr->slist_change_in_serialize = FALSE;
+
         while ( ( passes < H5C__MAX_PASSES_ON_FLUSH ) &&
 		( cache_ptr->slist_len != 0 ) &&
 		( protected_entries == 0 ) &&
@@ -1797,18 +2008,6 @@ H5C_flush_cache(H5F_t *f, hid_t primary_dxpl_id, hid_t secondary_dxpl_id, unsign
             {
                 hbool_t flushed_during_dep_loop = FALSE;
 
-                /* Start at beginning of skip list each time */
-                node_ptr = H5SL_first(cache_ptr->slist_ptr);
-                HDassert( node_ptr != NULL );
-
-                /* Get cache entry for this node */
-                next_entry_ptr = (H5C_cache_entry_t *)H5SL_item(node_ptr);
-                if ( NULL == next_entry_ptr )
-                    HGOTO_ERROR(H5E_CACHE, H5E_SYSTEM, FAIL, "next_entry_ptr == NULL ?!?!")
-                HDassert( next_entry_ptr->magic == H5C__H5C_CACHE_ENTRY_T_MAGIC );
-                HDassert( next_entry_ptr->is_dirty );
-                HDassert( next_entry_ptr->in_slist );
-
 #if H5C_DO_SANITY_CHECKS
                 /* For sanity checking, try to verify that the skip list has
                  * the expected size and number of entries at the end of each
@@ -1818,8 +2017,10 @@ H5C_flush_cache(H5F_t *f, hid_t primary_dxpl_id, hid_t secondary_dxpl_id, unsign
                  * or may not flush all the entries in the slist.
                  *
                  * To make things more entertaining, with the advent of the
-                 * fractal heap, the entry flush callback can cause entries
-                 * to be dirtied, resized, and/or moved.
+                 * fractal heap, the entry serialize callback can cause entries
+                 * to be dirtied, resized, and/or moved.  Also, the 
+                 * pre_serialize callback can result in an entry being 
+                 * removed from the cache via the take ownership flag.
                  *
                  * To deal with this, we first make note of the initial
                  * skip list length and size:
@@ -1834,7 +2035,8 @@ H5C_flush_cache(H5F_t *f, hid_t primary_dxpl_id, hid_t secondary_dxpl_id, unsign
                 flushed_entries_size = 0;
 
                 /* As mentioned above, there is the possibility that
-                 * entries will be dirtied, resized, and/or flushed during
+                 * entries will be dirtied, resized, flushed, or removed
+                 * from the cache via the take ownership flag  during
                  * our pass through the skip list.  To capture the number
                  * of entries added, and the skip list size delta,
                  * zero the slist_len_increase and slist_size_increase of
@@ -1851,53 +2053,60 @@ H5C_flush_cache(H5F_t *f, hid_t primary_dxpl_id, hid_t secondary_dxpl_id, unsign
                  */
 #endif /* H5C_DO_SANITY_CHECKS */
 
-                while ( node_ptr != NULL )
+                restart_slist_scan = TRUE;
+
+                while ( ( restart_slist_scan ) || ( node_ptr != NULL ) )
                 {
-                    entry_ptr = next_entry_ptr;
+                    if ( restart_slist_scan )
+                    {
+                        restart_slist_scan = FALSE;
 
-                    /* With the advent of the fractal heap, it is possible
-                     * that the flush callback will dirty and/or resize
-                     * other entries in the cache.  In particular, while
-                     * Quincey has promised me that this will never happen,
-                     * it is possible that the flush callback for an
-                     * entry may protect an entry that is not in the cache,
-                     * perhaps causing the cache to flush and possibly
-                     * evict the entry associated with node_ptr to make
-                     * space for the new entry.
-                     *
-                     * Thus we do a bit of extra sanity checking on entry_ptr,
-                     * and break out of this scan of the skip list if we
-                     * detect minor problems.  We have a bit of leaway on the
-                     * number of passes though the skip list, so this shouldn't
-                     * be an issue in the flush in and of itself, as it should
-                     * be all but impossible for this to happen more than once
-                     * in any flush.
-                     *
-                     * Observe that that breaking out of the scan early
-                     * shouldn't break the sanity checks just after the end
-                     * of this while loop.
-                     *
-                     * If an entry has merely been marked clean and removed from
-                     * the s-list, we simply break out of the scan.
-                     *
-                     * If the entry has been evicted, we flag an error and
-                     * exit.
-                     */
-#ifndef NDEBUG
-                    if ( entry_ptr->magic != H5C__H5C_CACHE_ENTRY_T_MAGIC ) {
+                        /* Start at beginning of skip list */
+                        node_ptr = H5SL_first(cache_ptr->slist_ptr);
 
-                        HGOTO_ERROR(H5E_CACHE, H5E_SYSTEM, FAIL, "entry_ptr->magic is invalid ?!?!")
+                        if ( node_ptr == NULL )
+                        {
+                            /* the slist is empty -- break out of inner loop */
+			    break;
+                        }
+                        HDassert( node_ptr != NULL );
 
-                    } else
-#endif /* NDEBUG */
-                    if ( ( ! entry_ptr->is_dirty ) ||
-                         ( ! entry_ptr->in_slist ) ) {
+                        /* Get cache entry for this node */
+                        next_entry_ptr = 
+                            (H5C_cache_entry_t *)H5SL_item(node_ptr);
 
-                        /* the s-list has been modified out from under us.
-                         * break out of the loop.
-                         */
-                        goto end_of_inner_loop;;
+                        if(NULL == next_entry_ptr)
+                            HGOTO_ERROR(H5E_CACHE, H5E_SYSTEM, FAIL, \
+                                        "next_entry_ptr == NULL ?!?!")
+
+                        HDassert( next_entry_ptr->magic == \
+                                  H5C__H5C_CACHE_ENTRY_T_MAGIC );
+                        HDassert( next_entry_ptr->is_dirty );
+                        HDassert( next_entry_ptr->in_slist );
                     }
+                    
+                    entry_ptr = next_entry_ptr;
+
+                    /* With the advent of the fractal heap, the free space
+                     * manager, and the version 3 cache, it is possible
+                     * that the pre-serialize or serialize callback will 
+                     * dirty, resize, or take ownership of other entries 
+                     * in the cache.  
+                     *
+                     * To deal with this, I have inserted code to detect any
+                     * change in the skip list not directly under the control
+                     * of this function.  If such modifications are detected,
+                     * we must re-start the scan of the skip list to avoid 
+                     * the possibility that the target of the next_entry_ptr
+                     * may have been flushed or deleted from the cache.
+                     *
+                     * To verify that all such possibilities have been dealt
+                     * with, we do a bit of extra sanity checking on 
+                     * entry_ptr.
+                     */
+                    HDassert(entry_ptr->magic == H5C__H5C_CACHE_ENTRY_T_MAGIC);
+                    HDassert(entry_ptr->in_slist);
+                    HDassert(entry_ptr->is_dirty);
 
                     /* increment node pointer now, before we delete its target
                      * from the slist.
@@ -1911,6 +2120,7 @@ H5C_flush_cache(H5F_t *f, hid_t primary_dxpl_id, hid_t secondary_dxpl_id, unsign
                         HDassert( next_entry_ptr->magic == H5C__H5C_CACHE_ENTRY_T_MAGIC );
                         HDassert( next_entry_ptr->is_dirty );
                         HDassert( next_entry_ptr->in_slist );
+                        HDassert( entry_ptr != next_entry_ptr );
                     } else {
                         next_entry_ptr = NULL;
 		    }
@@ -1927,9 +2137,9 @@ H5C_flush_cache(H5F_t *f, hid_t primary_dxpl_id, hid_t secondary_dxpl_id, unsign
 
                         if ( entry_ptr->is_protected ) {
 
-                            /* we probably have major problems -- but lets flush
-                             * everything we can before we decide whether to flag
-                             * an error.
+                            /* we probably have major problems -- but lets 
+                             * flush everything we can before we decide 
+                             * whether to flag an error.
                              */
                             tried_to_flush_protected_entry = TRUE;
                             protected_entries++;
@@ -1944,15 +2154,14 @@ H5C_flush_cache(H5F_t *f, hid_t primary_dxpl_id, hid_t secondary_dxpl_id, unsign
 #if H5C_DO_SANITY_CHECKS
                                 flushed_entries_count++;
                                 flushed_entries_size += (int64_t)entry_ptr->size;
+                                entry_size_change = 0;
 #endif /* H5C_DO_SANITY_CHECKS */
                                 status = H5C_flush_single_entry(f,
-                                                                primary_dxpl_id,
-                                                                secondary_dxpl_id,
-                                                                NULL,
-                                                                entry_ptr->addr,
-                                                                flags,
-                                                                &first_flush,
-                                                                FALSE);
+                                                            dxpl_id,
+                                                            entry_ptr->addr,
+                                                            flags,
+                                                            FALSE,
+                                                            entry_size_change_ptr);
                                 if ( status < 0 ) {
 
                                     /* This shouldn't happen -- if it does, 
@@ -1961,7 +2170,35 @@ H5C_flush_cache(H5F_t *f, hid_t primary_dxpl_id, hid_t secondary_dxpl_id, unsign
                                     HGOTO_ERROR(H5E_CACHE, H5E_CANTFLUSH, FAIL, \
                                                 "dirty pinned entry flush failed.")
                                 } /* end if */
+
+#if H5C_DO_SANITY_CHECKS
+                                /* it is possible that the entry size changed
+                                 * during flush -- update flushed_entries_size
+                                 * to account for this.
+                                 */
+                                flushed_entries_size += entry_size_change;
+#endif /* H5C_DO_SANITY_CHECKS */
+
                                 flushed_during_dep_loop = TRUE;
+
+                                if ((cache_ptr->slist_change_in_serialize) ||
+                                    (cache_ptr->slist_change_in_pre_serialize))
+                                {
+                                    /* The slist has been modified by something
+                                     * other than the simple removal of the 
+                                     * of the flushed entry after the flush.
+                                     * 
+                                     * This has the potential to corrupt the
+                                     * scan through the slist, so restart it.
+                                     */
+                                    restart_slist_scan = TRUE;
+                                    cache_ptr->slist_change_in_pre_serialize 
+                                        = FALSE;
+                                    cache_ptr->slist_change_in_serialize 
+                                        = FALSE;
+
+				    H5C__UPDATE_STATS_FOR_SLIST_SCAN_RESTART(cache_ptr)
+                                }
                             } /* end if */
                             else if(entry_ptr->flush_dep_height < curr_flush_dep_height)
                                 /* This shouldn't happen -- if it does, just scream and die.  */
@@ -1977,15 +2214,14 @@ H5C_flush_cache(H5F_t *f, hid_t primary_dxpl_id, hid_t secondary_dxpl_id, unsign
 #if H5C_DO_SANITY_CHECKS
                                 flushed_entries_count++;
                                 flushed_entries_size += (int64_t)entry_ptr->size;
+                                entry_size_change = 0;
 #endif /* H5C_DO_SANITY_CHECKS */
                                 status = H5C_flush_single_entry(f,
-                                                                primary_dxpl_id,
-                                                                secondary_dxpl_id,
-                                                                NULL,
-                                                                entry_ptr->addr,
-                                                                flags,
-                                                                &first_flush,
-                                                                FALSE);
+                                                            dxpl_id,
+                                                            entry_ptr->addr,
+                                                            flags,
+                                                            FALSE,
+                                                            entry_size_change_ptr);
                                 if ( status < 0 ) {
 
                                     /* This shouldn't happen -- if it does, 
@@ -1994,14 +2230,42 @@ H5C_flush_cache(H5F_t *f, hid_t primary_dxpl_id, hid_t secondary_dxpl_id, unsign
                                     HGOTO_ERROR(H5E_CACHE, H5E_CANTFLUSH, FAIL, \
                                                 "Can't flush entry.")
                                 }
+
+#if H5C_DO_SANITY_CHECKS
+                                /* it is possible that the entry size changed
+                                 * during flush -- update flushed_entries_size
+                                 * to account for this.
+                                 */
+                                flushed_entries_size += entry_size_change;
+#endif /* H5C_DO_SANITY_CHECKS */
+
                                 flushed_during_dep_loop = TRUE;
+
+                                if ((cache_ptr->slist_change_in_serialize) ||
+                                    (cache_ptr->slist_change_in_pre_serialize))
+                                {
+                                    /* The slist has been modified by something
+                                     * other than the simple removal of the 
+                                     * of the flushed entry after the flush.
+                                     * 
+                                     * This has the potential to corrupt the
+                                     * scan through the slist, so restart it.
+                                     */
+                                    restart_slist_scan = TRUE;
+                                    cache_ptr->slist_change_in_pre_serialize 
+                                        = FALSE;
+                                    cache_ptr->slist_change_in_serialize 
+                                        = FALSE;
+
+                                    H5C__UPDATE_STATS_FOR_SLIST_SCAN_RESTART(cache_ptr)
+                                }
                             } /* end if */
                             else if(entry_ptr->flush_dep_height < curr_flush_dep_height)
                                 /* This shouldn't happen -- if it does, just scream and die.  */
                                 HGOTO_ERROR(H5E_CACHE, H5E_CANTFLUSH, FAIL,  "dirty entry below current flush dep. height.")
                         } /* end else */
                     } /* end if */
-                } /* while ( node_ptr != NULL ) */
+                } /* while ( ( restart_slist_scan ) || ( node_ptr != NULL ) ) */
 
                 /* Check for incrementing flush dependency height */
                 if(flushed_during_dep_loop) {
@@ -2020,7 +2284,8 @@ H5C_flush_cache(H5F_t *f, hid_t primary_dxpl_id, hid_t secondary_dxpl_id, unsign
                     curr_flush_dep_height++;
 
             } /* while ( curr_flush_dep_height <= H5C__NUM_FLUSH_DEP_HEIGHTS) */
-end_of_inner_loop:
+
+            passes++;
 
 #if H5C_DO_SANITY_CHECKS
             /* Verify that the slist size and length are as expected. */
@@ -2032,8 +2297,6 @@ end_of_inner_loop:
 		       flushed_entries_size) == cache_ptr->slist_size );
 #endif /* H5C_DO_SANITY_CHECKS */
 
-	    passes++;
-
 	} /* while */
 
         HDassert( protected_entries <= cache_ptr->pl_len );
@@ -2098,12 +2361,10 @@ done:
  */
 herr_t
 H5C_flush_to_min_clean(H5F_t * f,
-                       hid_t   primary_dxpl_id,
-                       hid_t   secondary_dxpl_id)
+		       hid_t    dxpl_id)
 {
     H5C_t *             cache_ptr;
     herr_t      	result;
-    hbool_t		first_flush = TRUE;
     hbool_t		write_permitted;
 #if 0 /* modified code -- commented out for now */
     int			i;
@@ -2146,11 +2407,9 @@ H5C_flush_to_min_clean(H5F_t * f,
     }
 #if 1 /* original code */
     result = H5C_make_space_in_cache(f,
-                                     primary_dxpl_id,
-                                     secondary_dxpl_id,
+                                     dxpl_id,
                                      (size_t)0,
-                                     write_permitted,
-                                     &first_flush);
+                                     write_permitted);
 
     if ( result < 0 ) {
 
@@ -2645,8 +2904,7 @@ H5C_get_trace_file_ptr_from_entry(const H5C_cache_entry_t *entry_ptr)
  */
 herr_t
 H5C_insert_entry(H5F_t *             f,
-                 hid_t		     primary_dxpl_id,
-                 hid_t		     secondary_dxpl_id,
+                 hid_t		     dxpl_id,
                  const H5C_class_t * type,
                  haddr_t 	     addr,
                  void *		     thing,
@@ -2654,7 +2912,6 @@ H5C_insert_entry(H5F_t *             f,
 {
     H5C_t *             cache_ptr;
     herr_t		result;
-    hbool_t		first_flush = TRUE;
     hbool_t		insert_pinned;
     hbool_t             flush_last;
 #ifdef H5_HAVE_PARALLEL
@@ -2678,8 +2935,6 @@ H5C_insert_entry(H5F_t *             f,
     HDassert( cache_ptr );
     HDassert( cache_ptr->magic == H5C__H5C_T_MAGIC );
     HDassert( type );
-    HDassert( type->flush );
-    HDassert( type->size );
     HDassert( H5F_addr_defined(addr) );
     HDassert( thing );
 
@@ -2718,15 +2973,16 @@ H5C_insert_entry(H5F_t *             f,
             HGOTO_ERROR(H5E_CACHE, H5E_CANTINS, FAIL, "duplicate entry in cache.")
     } /* end if */
 
-#ifndef NDEBUG
     entry_ptr->magic = H5C__H5C_CACHE_ENTRY_T_MAGIC;
-#endif /* NDEBUG */
     entry_ptr->cache_ptr = cache_ptr;
     entry_ptr->addr  = addr;
     entry_ptr->type  = type;
 
+    entry_ptr->image_ptr = NULL;
+    entry_ptr->image_up_to_date = FALSE;
+
     /* Apply tag to newly inserted entry */
-    if(H5C_tag_entry(cache_ptr, entry_ptr, primary_dxpl_id) < 0)
+    if(H5C_tag_entry(cache_ptr, entry_ptr, dxpl_id) < 0)
         HGOTO_ERROR(H5E_CACHE, H5E_CANTTAG, FAIL, "Cannot tag metadata entry")
 
     entry_ptr->is_protected = FALSE;
@@ -2747,10 +3003,27 @@ H5C_insert_entry(H5F_t *             f,
     /* not protected, so can't be dirtied */
     entry_ptr->dirtied  = FALSE;
 
-    /* Retrieve the size of the thing */
-    if((type->size)(f, thing, &(entry_ptr->size)) < 0)
+    /* Retrieve the size of the thing.  Set the compressed field to FALSE
+     * and the compressed_size field to zero first, as they may not be 
+     * initialized by the image_len call.
+     */
+    entry_ptr->compressed = FALSE;
+    entry_ptr->compressed_size = 0;
+    if((type->image_len)(thing, &(entry_ptr->size), &(entry_ptr->compressed), 
+                         &(entry_ptr->compressed_size)) < 0)
         HGOTO_ERROR(H5E_RESOURCE, H5E_CANTGETSIZE, FAIL, "Can't get size of thing")
     HDassert(entry_ptr->size > 0 &&  entry_ptr->size < H5C_MAX_ENTRY_SIZE);
+    HDassert(((type->flags & H5C__CLASS_COMPRESSED_FLAG) != 0) ||
+             (entry_ptr->compressed == FALSE));
+
+    /* entry has just been inserted -- thus compressed size cannot have 
+     * been computed yet.  Thus if entry_ptr->compressed is TRUE, 
+     * entry_ptr->size must equal entry_ptr->compressed_size.
+     */
+    HDassert((entry_ptr->compressed == FALSE) ||
+             (entry_ptr->size == entry_ptr->compressed_size));
+    HDassert((entry_ptr->compressed == TRUE) || 
+             (entry_ptr->compressed_size == 0));
 
     entry_ptr->in_slist = FALSE;
 
@@ -2761,7 +3034,6 @@ H5C_insert_entry(H5F_t *             f,
 
     entry_ptr->flush_in_progress = FALSE;
     entry_ptr->destroy_in_progress = FALSE;
-    entry_ptr->free_file_space_on_destroy = FALSE;
 
     /* Initialize flush dependency height fields */
     entry_ptr->flush_dep_parent = NULL;
@@ -2860,11 +3132,9 @@ H5C_insert_entry(H5F_t *             f,
          */
 
         result = H5C_make_space_in_cache(f,
-                                         primary_dxpl_id,
-                                         secondary_dxpl_id,
+                                         dxpl_id,
                                          space_needed,
-                                         write_permitted,
-                                         &first_flush);
+                                         write_permitted);
 
         if ( result < 0 ) {
 
@@ -2956,18 +3226,39 @@ done:
  * Programmer:  John Mainzer
  *              7/5/05
  *
+ * Changes:     Tidied up code, removeing some old commented out 
+ *		code that had been left in pending success of the 
+ *		new version.
+ *
+ *		Note that unlike H5C_apply_candidate_list(), 
+ *		H5C_mark_entries_as_clean() makes all its calls to 
+ *		H6C_flush_single_entry() with the 
+ *		H5C__FLUSH_CLEAR_ONLY_FLAG set.  As a result, 
+ *		the pre_serialize() and serialize calls are not made.
+ *
+ *		This then implies that (assuming such actions were 
+ *		permitted in the parallel case) no loads, dirties, 
+ *		resizes, or removals of other entries can occur as 
+ *		a side effect of the flush.  Hence, there is no need
+ *		for the checks for entry removal / status change 
+ *		that I ported to H5C_apply_candidate_list().
+ *
+ *		However, if (in addition to allowing such operations
+ *		in the parallel case), we allow such operations outside
+ *		of the pre_serialize / serialize routines, this may 
+ *		cease to be the case -- requiring a review of this 
+ *		function.
+ *
  *-------------------------------------------------------------------------
  */
 #ifdef H5_HAVE_PARALLEL
 herr_t
 H5C_mark_entries_as_clean(H5F_t *  f,
-                          hid_t     primary_dxpl_id,
-                          hid_t     secondary_dxpl_id,
+                          hid_t     dxpl_id,
                           int32_t   ce_array_len,
                           haddr_t * ce_array_ptr)
 {
     H5C_t *             cache_ptr;
-    hbool_t		first_flush = TRUE;
     int			entries_cleared;
     int			entries_examined;
     int                 i;
@@ -3061,27 +3352,9 @@ H5C_mark_entries_as_clean(H5F_t *  f,
 #endif /* H5C_DO_SANITY_CHECKS */
             HGOTO_ERROR(H5E_CACHE, H5E_SYSTEM, FAIL, \
                         "Listed entry not dirty?!?!?.")
-#if 0 /* original code */
-        } else if ( entry_ptr->is_protected ) {
-
-            entry_ptr->clear_on_unprotect = TRUE;
 
         } else {
 
-            if ( H5C_flush_single_entry(f,
-                                        primary_dxpl_id,
-                                        secondary_dxpl_id,
-                                        entry_ptr->type,
-                                        addr,
-                                        H5C__FLUSH_CLEAR_ONLY_FLAG,
-                                        &first_flush,
-                                        TRUE) < 0 ) {
-
-                HGOTO_ERROR(H5E_CACHE, H5E_SYSTEM, FAIL, "Can't clear entry.")
-            }
-        }
-#else /* modified code */
-        } else {
             /* Mark the entry to be cleared on unprotect.  We will
              * scan the LRU list shortly, and clear all those entries
              * not currently protected.
@@ -3102,13 +3375,32 @@ H5C_mark_entries_as_clean(H5F_t *  f,
 	    }
 #endif /* H5C_DO_SANITY_CHECKS */
         }
-#endif /* end modified code */
     }
-#if 1 /* modified code */
+
     /* Scan through the LRU list from back to front, and flush the
      * entries whose clear_on_unprotect flags are set.  Observe that
      * any protected entries will not be on the LRU, and therefore
      * will not be flushed at this time.
+     *
+     * Note that unlike H5C_apply_candidate_list(), 
+     * H5C_mark_entries_as_clean() makes all its calls to 
+     * H6C_flush_single_entry() with the H5C__FLUSH_CLEAR_ONLY_FLAG 
+     * set.  As a result, the pre_serialize() and serialize calls are 
+     * not made.
+     *
+     * This then implies that (assuming such actions were 
+     * permitted in the parallel case) no loads, dirties, 
+     * resizes, or removals of other entries can occur as 
+     * a side effect of the flush.  Hence, there is no need
+     * for the checks for entry removal / status change 
+     * that I ported to H5C_apply_candidate_list().
+     *
+     * However, if (in addition to allowing such operations
+     * in the parallel case), we allow such operations outside
+     * of the pre_serialize / serialize routines, this may 
+     * cease to be the case -- requiring a review of this 
+     * point.
+     *					JRM -- 4/7/15
      */
 
     entries_cleared = 0;
@@ -3128,13 +3420,11 @@ H5C_mark_entries_as_clean(H5F_t *  f,
             entries_cleared++;
 
             if ( H5C_flush_single_entry(f,
-                                        primary_dxpl_id,
-                                        secondary_dxpl_id,
-                                        clear_ptr->type,
+                                        dxpl_id,
                                         clear_ptr->addr,
                                         H5C__FLUSH_CLEAR_ONLY_FLAG,
-                                        &first_flush,
-                                        TRUE) < 0 ) {
+                                        TRUE,
+                                        NULL) < 0 ) {
 
                 HGOTO_ERROR(H5E_CACHE, H5E_SYSTEM, FAIL, "Can't clear entry.")
             }
@@ -3165,13 +3455,11 @@ H5C_mark_entries_as_clean(H5F_t *  f,
             entries_cleared++;
 
             if ( H5C_flush_single_entry(f,
-                                        primary_dxpl_id,
-                                        secondary_dxpl_id,
-                                        clear_ptr->type,
+                                        dxpl_id,
                                         clear_ptr->addr,
                                         H5C__FLUSH_CLEAR_ONLY_FLAG,
-                                        &first_flush,
-                                        TRUE) < 0 ) {
+                                        TRUE,
+                                        NULL) < 0 ) {
 
                 HGOTO_ERROR(H5E_CACHE, H5E_SYSTEM, FAIL, "Can't clear entry.")
             }
@@ -3202,7 +3490,6 @@ H5C_mark_entries_as_clean(H5F_t *  f,
     }
     HDassert( (entries_cleared + i) == ce_array_len );
 #endif /* H5C_DO_SANITY_CHECKS */
-#endif /* modified code */
 
 done:
 
@@ -3278,6 +3565,7 @@ H5C_mark_entry_dirty(void *thing)
 
         /* mark the entry as dirty if it isn't already */
         entry_ptr->is_dirty = TRUE;
+	entry_ptr->image_up_to_date = FALSE;
 
 	if ( was_pinned_unprotected_and_clean ) {
 
@@ -3427,36 +3715,32 @@ H5C_move_entry(H5C_t *	     cache_ptr,
         was_dirty = entry_ptr->is_dirty;
 #endif /* H5C_MAINTAIN_CLEAN_AND_DIRTY_LRU_LISTS */
 
-	if ( ! ( entry_ptr->flush_in_progress ) ) {
-
-            entry_ptr->is_dirty = TRUE;
-	}
+        entry_ptr->is_dirty = TRUE;
+        /* This shouldn't be needed, but it keeps the test code happy */
+        entry_ptr->image_up_to_date = FALSE;
 
         H5C__INSERT_IN_INDEX(cache_ptr, entry_ptr, FAIL)
 
-	if ( ! ( entry_ptr->flush_in_progress ) ) {
-
-            H5C__INSERT_ENTRY_IN_SLIST(cache_ptr, entry_ptr, FAIL)
+        H5C__INSERT_ENTRY_IN_SLIST(cache_ptr, entry_ptr, FAIL)
 
 #if H5C_DO_SANITY_CHECKS
 
-            if ( removed_entry_from_slist ) {
-
-		/* we just removed the entry from the slist.  Thus we
-		 * must touch up cache_ptr->slist_len_increase and
-		 * cache_ptr->slist_size_increase to keep from skewing
-		 * the sanity checks.
-		 */
-		HDassert( cache_ptr->slist_len_increase > 1 );
-		HDassert( cache_ptr->slist_size_increase > 
-                          (int64_t)(entry_ptr->size) );
+        if ( removed_entry_from_slist ) {
 
-		cache_ptr->slist_len_increase -= 1;
-		cache_ptr->slist_size_increase -= (int64_t)(entry_ptr->size);
-	    }
+	    /* we just removed the entry from the slist.  Thus we
+	     * must touch up cache_ptr->slist_len_increase and
+	     * cache_ptr->slist_size_increase to keep from skewing
+	     * the sanity checks.
+	     */
+	    cache_ptr->slist_len_increase -= 1;
+	    cache_ptr->slist_size_increase -= (int64_t)(entry_ptr->size);
+        }
 
 #endif /* H5C_DO_SANITY_CHECKS */
 
+	if ( ! ( entry_ptr->flush_in_progress ) ) {
+
+            /* skip the update if a flush is in progress */
             H5C__UPDATE_RP_FOR_MOVE(cache_ptr, entry_ptr, was_dirty, FAIL)
         }
     }
@@ -3536,6 +3820,11 @@ H5C_resize_entry(void *thing, size_t new_size)
 
         /* mark the entry as dirty if it isn't already */
         entry_ptr->is_dirty = TRUE;
+        entry_ptr->image_up_to_date = FALSE;
+
+        /* Release the current image */
+        if( entry_ptr->image_ptr )
+            entry_ptr->image_ptr = H5MM_xfree(entry_ptr->image_ptr);
 
         /* do a flash cache size increase if appropriate */
         if ( cache_ptr->flash_size_increase_possible ) {
@@ -3743,18 +4032,6 @@ done:
  *		or flushed -- nor may it be accessed by another call to
  *		H5C_protect.  Any attempt to do so will result in a failure.
  *
- *		The primary_dxpl_id and secondary_dxpl_id parameters
- *		specify the dxpl_ids used on the first write occasioned
- *		by the insertion (primary_dxpl_id), and on all subsequent
- *		writes (secondary_dxpl_id).  This is useful in the
- *		metadata cache, but may not be needed elsewhere.  If so,
- *		just use the same dxpl_id for both parameters.
- *
- *		All reads are performed with the primary_dxpl_id.
- *
- *		Similarly, the primary_dxpl_id is passed to the
- *		check_write_permitted function if it is called.
- *
  * Return:      Success:        Ptr to the desired entry
  *              Failure:        NULL
  *
@@ -3776,12 +4053,21 @@ done:
  *              entries long before we actually have to evict something
  *              to make space.
  *
+ *		JRM -- 9/1/14
+ *		Replace the old rw parameter with the flags parameter.
+ *		This allows H5C_protect to accept flags other than 
+ *		H5C__READ_ONLY_FLAG.  
+ *
+ *		Added support for the H5C__FLUSH_LAST_FLAG and 
+ *		H5C__FLUSH_COLLECTIVELY_FLAG flags.  At present, these 
+ *		flags are only applied if the entry is not in cache, and 
+ *		is loaded into the cache as a result of this call.
+ *
  *-------------------------------------------------------------------------
  */
 void *
 H5C_protect(H5F_t *		f,
-            hid_t	        primary_dxpl_id,
-            hid_t	        secondary_dxpl_id,
+            hid_t	        dxpl_id,
             const H5C_class_t * type,
             haddr_t 	        addr,
             void *              udata,
@@ -3789,9 +4075,12 @@ H5C_protect(H5F_t *		f,
 {
     H5C_t *		cache_ptr;
     hbool_t		hit;
-    hbool_t		first_flush;
     hbool_t		have_write_permitted = FALSE;
     hbool_t		read_only = FALSE;
+    hbool_t             flush_last;
+#ifdef H5_HAVE_PARALLEL
+    hbool_t             flush_collectively;
+#endif /* H5_HAVE_PARALLEL */
     hbool_t		write_permitted;
     herr_t		result;
     size_t		empty_space;
@@ -3812,8 +4101,6 @@ H5C_protect(H5F_t *		f,
     HDassert( cache_ptr );
     HDassert( cache_ptr->magic == H5C__H5C_T_MAGIC );
     HDassert( type );
-    HDassert( type->flush );
-    HDassert( type->load );
     HDassert( H5F_addr_defined(addr) );
 
 #if H5C_DO_EXTREME_SANITY_CHECKS
@@ -3827,6 +4114,10 @@ H5C_protect(H5F_t *		f,
 #endif /* H5C_DO_EXTREME_SANITY_CHECKS */
 
     read_only          = ( (flags & H5C__READ_ONLY_FLAG) != 0 );
+    flush_last         = ( (flags & H5C__FLUSH_LAST_FLAG) != 0 );
+#ifdef H5_HAVE_PARALLEL
+    flush_collectively = ( (flags & H5C__FLUSH_COLLECTIVELY_FLAG) != 0 );
+#endif /* H5_HAVE_PARALLEL */
 
     /* first check to see if the target is in cache */
     H5C__SEARCH_INDEX(cache_ptr, addr, entry_ptr, NULL)
@@ -3845,7 +4136,7 @@ H5C_protect(H5F_t *		f,
            from disk. */
 
         /* Get the dataset transfer property list */
-        if(NULL == (dxpl = (H5P_genplist_t *)H5I_object_verify(primary_dxpl_id, H5I_GENPROP_LST)))
+        if(NULL == (dxpl = (H5P_genplist_t *)H5I_object_verify(dxpl_id, H5I_GENPROP_LST)))
             HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, NULL, "not a property list");
 
         /* Get the tag from the DXPL */
@@ -3871,7 +4162,7 @@ H5C_protect(H5F_t *		f,
 
         hit = FALSE;
 
-        thing = H5C_load_entry(f, primary_dxpl_id, type, addr, udata);
+        thing = H5C_load_entry(f, dxpl_id, type, addr, udata);
 
         if ( thing == NULL ) {
 
@@ -3881,7 +4172,7 @@ H5C_protect(H5F_t *		f,
         entry_ptr = (H5C_cache_entry_t *)thing;
 
         /* Apply tag to newly protected entry */
-        if(H5C_tag_entry(cache_ptr, entry_ptr, primary_dxpl_id) < 0)
+        if(H5C_tag_entry(cache_ptr, entry_ptr, dxpl_id) < 0)
             HGOTO_ERROR(H5E_CACHE, H5E_CANTTAG, NULL, "Cannot tag metadata entry")
 
         /* If the entry is very large, and we are configured to allow it,
@@ -3936,7 +4227,6 @@ H5C_protect(H5F_t *		f,
 
                     have_write_permitted = TRUE;
 
-                    first_flush = TRUE;
                 }
             } else {
 
@@ -3944,7 +4234,6 @@ H5C_protect(H5F_t *		f,
 
                 have_write_permitted = TRUE;
 
-                first_flush = TRUE;
             }
 
             HDassert( entry_ptr->size <= H5C_MAX_ENTRY_SIZE );
@@ -3985,10 +4274,10 @@ H5C_protect(H5F_t *		f,
              * see no point in worrying about the fourth.
              */
 
-            result = H5C_make_space_in_cache(f, primary_dxpl_id,
-                                             secondary_dxpl_id,
-                                             space_needed, write_permitted,
-                                             &first_flush);
+            result = H5C_make_space_in_cache(f, 
+                                             dxpl_id, 
+                                             space_needed,
+                                             write_permitted);
 
             if ( result < 0 ) {
 
@@ -4002,7 +4291,24 @@ H5C_protect(H5F_t *		f,
          *
          * This is no longer true -- due to a bug fix, we may modify
          * data on load to repair a file.
+         *
+         *   *******************************************
+         *
+         * Set the flush_last (and possibly flush_collectively) fields 
+ 	 * of the newly loaded entry before inserting it into the 
+         * index.  Must do this, as the index tracked the number of 
+         * entries with the flush_last field set, but assumes that 
+         * the field will not change after insertion into the index.
+         *
+         * Note that this means that the H5C__FLUSH_LAST_FLAG and 
+         * H5C__FLUSH_COLLECTIVELY_FLAG flags are ignored if the 
+         * entry is already in cache.
          */
+        entry_ptr->flush_me_last = flush_last;
+#ifdef H5_HAVE_PARALLEL
+        entry_ptr->flush_me_collectively = flush_collectively;
+#endif
+
         H5C__INSERT_IN_INDEX(cache_ptr, entry_ptr, NULL)
 
         if ( ( entry_ptr->is_dirty ) && ( ! (entry_ptr->in_slist) ) ) {
@@ -4017,11 +4323,11 @@ H5C_protect(H5F_t *		f,
          */
         H5C__UPDATE_RP_FOR_INSERTION(cache_ptr, entry_ptr, NULL)
 
-        /* If the entry's type has a 'notify' callback send a 'after insertion'
+        /* If the entry's type has a 'notify' callback send a 'after load'
          * notice now that the entry is fully integrated into the cache.
          */
         if(entry_ptr->type->notify &&
-                (entry_ptr->type->notify)(H5C_NOTIFY_ACTION_AFTER_INSERT, entry_ptr) < 0)
+                (entry_ptr->type->notify)(H5C_NOTIFY_ACTION_AFTER_LOAD, entry_ptr) < 0)
             HGOTO_ERROR(H5E_CACHE, H5E_CANTNOTIFY, NULL, "can't notify client about entry inserted into cache")
     }
 
@@ -4083,7 +4389,6 @@ H5C_protect(H5F_t *		f,
 
                     have_write_permitted = TRUE;
 
-                    first_flush = TRUE;
                 }
             } else {
 
@@ -4091,7 +4396,6 @@ H5C_protect(H5F_t *		f,
 
                 have_write_permitted = TRUE;
 
-                first_flush = TRUE;
             }
         }
 
@@ -4100,10 +4404,8 @@ H5C_protect(H5F_t *		f,
                (cache_ptr->resize_ctl).epoch_length ) ) {
 
             result = H5C__auto_adjust_cache_size(f,
-                                                 primary_dxpl_id,
-                                                 secondary_dxpl_id,
-                                                 write_permitted,
-                                                 &first_flush);
+                                                 dxpl_id,
+                                                 write_permitted);
             if ( result != SUCCEED ) {
 
                 HGOTO_ERROR(H5E_CACHE, H5E_CANTPROTECT, NULL, \
@@ -4137,10 +4439,10 @@ H5C_protect(H5F_t *		f,
 		if(cache_ptr->index_size > cache_ptr->max_cache_size)
                     cache_ptr->cache_full = TRUE;
 
-                result = H5C_make_space_in_cache(f, primary_dxpl_id,
-                                                 secondary_dxpl_id,
-                                                 (size_t)0, write_permitted,
-                                                 &first_flush);
+                result = H5C_make_space_in_cache(f,
+                                                 dxpl_id,
+                                                 (size_t)0,
+                                                 write_permitted);
 
                 if ( result < 0 ) {
 
@@ -4636,6 +4938,10 @@ done:
  *              total_entries_skipped_in_msic, total_entries_scanned_in_msic,
  *              and max_entries_skipped_in_msic fields.
  *
+ *		JRM -- 4/11/15
+ *		Added code displaying the new slist_scan_restarts,
+ *		LRU_scan_restarts, and hash_bucket_scan_restarts fields;
+ *
  *-------------------------------------------------------------------------
  */
 herr_t
@@ -4659,6 +4965,7 @@ H5C_stats(H5C_t * cache_ptr,
     int64_t     total_clears = 0;
     int64_t     total_flushes = 0;
     int64_t     total_evictions = 0;
+    int64_t     total_take_ownerships = 0;
     int64_t     total_moves = 0;
     int64_t     total_entry_flush_moves = 0;
     int64_t     total_cache_flush_moves = 0;
@@ -4687,6 +4994,8 @@ H5C_stats(H5C_t * cache_ptr,
 
     FUNC_ENTER_NOAPI(FAIL)
 
+    HDassert( cache_ptr->magic == H5C__H5C_T_MAGIC );
+
     /* This would normally be an assert, but we need to use an HGOTO_ERROR
      * call to shut up the compiler.
      */
@@ -4713,6 +5022,7 @@ H5C_stats(H5C_t * cache_ptr,
         total_clears            += cache_ptr->clears[i];
         total_flushes           += cache_ptr->flushes[i];
         total_evictions         += cache_ptr->evictions[i];
+        total_take_ownerships   += cache_ptr->take_ownerships[i];
         total_moves             += cache_ptr->moves[i];
 	total_entry_flush_moves += cache_ptr->entry_flush_moves[i];
 	total_cache_flush_moves += cache_ptr->cache_flush_moves[i];
@@ -4864,11 +5174,16 @@ H5C_stats(H5C_t * cache_ptr,
               (long)max_read_protects);
 
     HDfprintf(stdout,
-              "%s  Total clears / flushes / evictions = %ld / %ld / %ld\n",
+              "%s  Total clears / flushes             = %ld / %ld\n",
               cache_ptr->prefix,
               (long)total_clears,
-              (long)total_flushes,
-              (long)total_evictions);
+              (long)total_flushes);
+
+    HDfprintf(stdout,
+              "%s  Total evictions / take ownerships  = %ld / %ld\n",
+              cache_ptr->prefix,
+              (long)total_evictions,
+              (long)total_take_ownerships);
 
     HDfprintf(stdout,
 	      "%s  Total insertions(pinned) / moves   = %ld(%ld) / %ld\n",
@@ -4940,6 +5255,13 @@ H5C_stats(H5C_t * cache_ptr,
               (long long)(cache_ptr->total_entries_scanned_in_msic -
                             cache_ptr->entries_scanned_to_make_space));
 
+    HDfprintf(stdout, 
+              "%s  slist/LRU/hash bkt scan restarts   = %lld / %lld / %lld.\n",
+              cache_ptr->prefix, 
+              (long long)(cache_ptr->slist_scan_restarts),
+              (long long)(cache_ptr->LRU_scan_restarts),
+              (long long)(cache_ptr->hash_bucket_scan_restarts));
+
 #if H5C_COLLECT_CACHE_ENTRY_STATS
 
     HDfprintf(stdout, "%s  aggregate max / min accesses       = %d / %d\n",
@@ -4993,11 +5315,16 @@ H5C_stats(H5C_t * cache_ptr,
                       (int)(cache_ptr->max_read_protects[i]));
 
             HDfprintf(stdout,
-                     "%s    clears / flushes / evictions   = %ld / %ld / %ld\n",
+                      "%s    clears / flushes               = %ld / %ld\n", 
                       cache_ptr->prefix,
                       (long)(cache_ptr->clears[i]),
-                      (long)(cache_ptr->flushes[i]),
-                      (long)(cache_ptr->evictions[i]));
+                      (long)(cache_ptr->flushes[i]));
+
+            HDfprintf(stdout,
+                      "%s    evictions / take ownerships    = %ld / %ld\n",
+                      cache_ptr->prefix,
+                      (long)(cache_ptr->evictions[i]),
+                      (long)(cache_ptr->take_ownerships[i]));
 
             HDfprintf(stdout,
                       "%s    insertions(pinned) / moves     = %ld(%ld) / %ld\n",
@@ -5092,6 +5419,11 @@ done:
  *              total_entries_skipped_in_msic, total_entries_scanned_in_msic,
  *              and max_entries_skipped_in_msic fields.
  *
+ *		JRM 4/11/15
+ *		Added code to initialize the new slist_scan_restarts,
+ *		LRU_scan_restarts, hash_bucket_scan_restarts, and 
+ *		take_ownerships fields.
+ *
  *-------------------------------------------------------------------------
  */
 void
@@ -5125,6 +5457,7 @@ H5C_stats__reset(H5C_t H5_ATTR_UNUSED * cache_ptr)
         cache_ptr->clears[i]			= 0;
         cache_ptr->flushes[i]			= 0;
         cache_ptr->evictions[i]	 		= 0;
+        cache_ptr->take_ownerships[i] 		= 0;
         cache_ptr->moves[i]	 		= 0;
         cache_ptr->entry_flush_moves[i]		= 0;
         cache_ptr->cache_flush_moves[i]		= 0;
@@ -5167,6 +5500,10 @@ H5C_stats__reset(H5C_t H5_ATTR_UNUSED * cache_ptr)
     cache_ptr->max_entries_scanned_in_msic      = 0;
     cache_ptr->entries_scanned_to_make_space    = 0;
 
+    cache_ptr->slist_scan_restarts		= 0;
+    cache_ptr->LRU_scan_restarts		= 0;
+    cache_ptr->hash_bucket_scan_restarts	= 0;
+
 #if H5C_COLLECT_CACHE_ENTRY_STATS
 
     for ( i = 0; i <= cache_ptr->max_type_id; i++ )
@@ -5319,6 +5656,107 @@ done:
 
 
 /*-------------------------------------------------------------------------
+ * Function:    H5C_dump_cache_skip_list
+ *
+ * Purpose:     Debugging routine that prints a summary of the contents of 
+ *		the skip list used by the metadata cache metadata cache to 
+ *		maintain an address sorted list of dirty entries.
+ *
+ * Return:      Non-negative on success/Negative on failure
+ *
+ * Programmer:  John Mainzer
+ *              11/15/14
+ *
+ *-------------------------------------------------------------------------
+ */
+#if 0 /* debugging routine */
+herr_t
+H5C_dump_cache_skip_list(H5C_t * cache_ptr, char * calling_fcn)
+{
+    herr_t              ret_value = SUCCEED;   /* Return value */
+    int                 i;
+    H5C_cache_entry_t * entry_ptr = NULL;
+    H5SL_node_t *       node_ptr = NULL;
+
+    FUNC_ENTER_NOAPI(FAIL)
+
+    HDassert(cache_ptr != NULL);
+    HDassert(cache_ptr->magic == H5C__H5C_T_MAGIC);
+    HDassert(calling_fcn != NULL);
+
+    HDfprintf(stdout, "\n\nDumping metadata cache skip list from %s.\n",
+              calling_fcn);
+    HDfprintf(stdout, "	slist len = %d.\n", cache_ptr->slist_len);
+    HDfprintf(stdout, "	slist size = %lld.\n", 
+              (long long)(cache_ptr->slist_size));
+
+    if ( cache_ptr->slist_len > 0 )
+    {
+        /* If we get this far, all entries in the cache are listed in the
+         * skip list -- scan the skip list generating the desired output.
+         */
+
+        HDfprintf(stdout,
+                  "Num:    Addr:               Len: Prot/Pind: Dirty: Type:\n");
+
+        i = 0;
+
+        node_ptr = H5SL_first(cache_ptr->slist_ptr);
+
+        if ( node_ptr != NULL ) {
+
+            entry_ptr = (H5C_cache_entry_t *)H5SL_item(node_ptr);
+
+        } else {
+
+            entry_ptr = NULL;
+        }
+
+        while ( entry_ptr != NULL ) {
+
+            HDassert( entry_ptr->magic == H5C__H5C_CACHE_ENTRY_T_MAGIC );
+
+            HDfprintf(stdout,
+               "%s%d       0x%016llx  %4lld    %d/%d       %d    %s\n",
+               cache_ptr->prefix, i,
+               (long long)(entry_ptr->addr),
+               (long long)(entry_ptr->size),
+               (int)(entry_ptr->is_protected),
+               (int)(entry_ptr->is_pinned),
+               (int)(entry_ptr->is_dirty),
+               entry_ptr->type->name);
+
+            HDfprintf(stdout, "		node_ptr = 0x%llx, item = 0x%llx\n",
+                      (unsigned long long)node_ptr,
+                      (unsigned long long)H5SL_item(node_ptr));
+
+            /* increment node_ptr before we delete its target */
+            node_ptr = H5SL_next(node_ptr);
+
+            if ( node_ptr != NULL ) {
+
+                entry_ptr = (H5C_cache_entry_t *)H5SL_item(node_ptr);
+
+            } else {
+
+                entry_ptr = NULL;
+            }
+
+            i++;
+        }
+    }
+
+    HDfprintf(stdout, "\n\n");
+
+done:
+
+    FUNC_LEAVE_NOAPI(ret_value)
+
+} /* H5C_dump_cache_skip_list() */
+#endif /* debugging routine */
+
+
+/*-------------------------------------------------------------------------
  * Function:    H5C_unpin_entry_from_client()
  *
  * Purpose:	Internal routine to unpin a cache entry from a client action.
@@ -5474,8 +5912,7 @@ done:
  */
 herr_t
 H5C_unprotect(H5F_t *		  f,
-              hid_t		  primary_dxpl_id,
-              hid_t		  secondary_dxpl_id,
+              hid_t		  dxpl_id,
               const H5C_class_t * type,
               haddr_t		  addr,
               void *		  thing,
@@ -5515,8 +5952,6 @@ H5C_unprotect(H5F_t *		  f,
     HDassert( cache_ptr );
     HDassert( cache_ptr->magic == H5C__H5C_T_MAGIC );
     HDassert( type );
-    HDassert( type->clear );
-    HDassert( type->flush );
     HDassert( H5F_addr_defined(addr) );
     HDassert( thing );
     HDassert( ! ( pin_entry && unpin_entry ) );
@@ -5615,6 +6050,19 @@ H5C_unprotect(H5F_t *		  f,
         /* Mark the entry as dirty if appropriate */
         entry_ptr->is_dirty = (entry_ptr->is_dirty || dirtied);
 
+        /* the image_up_to_date field was introduced to support 
+         * journaling.  Until we re-introduce journaling, this 
+         * field should be equal to !entry_ptr->is_dirty.  
+         *
+         * When journaling is re-enabled it should be set 
+         * to FALSE if dirtied is TRUE.
+         */
+#if 1 /* JRM */
+	entry_ptr->image_up_to_date = FALSE;
+#else /* JRM */
+	entry_ptr->image_up_to_date = !entry_ptr->is_dirty;
+#endif /* JRM */
+
         /* Update index for newly dirtied entry */
         if(was_clean && entry_ptr->is_dirty)
 	    H5C__UPDATE_INDEX_FOR_ENTRY_DIRTY(cache_ptr, entry_ptr)
@@ -5656,13 +6104,6 @@ H5C_unprotect(H5F_t *		  f,
          *                                             JRM - 5/19/04
          */
         if ( deleted ) {
-
-            /* the following first flush flag will never be used as we are
-             * calling H5C_flush_single_entry with both the
-             * H5C__FLUSH_CLEAR_ONLY_FLAG and H5C__FLUSH_INVALIDATE_FLAG flags.
-	     * However, it is needed for the function call.
-             */
-            hbool_t	dummy_first_flush = TRUE;
             unsigned    flush_flags = (H5C__FLUSH_CLEAR_ONLY_FLAG |
                                          H5C__FLUSH_INVALIDATE_FLAG);
 
@@ -5684,36 +6125,40 @@ H5C_unprotect(H5F_t *		  f,
                             "hash table contains multiple entries for addr?!?.")
             }
 
-            /* Pass along 'free file space' flag to cache client */
-
-            entry_ptr->free_file_space_on_destroy = free_file_space;
+            /* Set the 'free file space' flag for the flush, if needed */
+            if(free_file_space)
+                flush_flags |= H5C__FREE_FILE_SPACE_FLAG;
 
             /* Set the "take ownership" flag for the flush, if needed */
             if(take_ownership)
                 flush_flags |= H5C__TAKE_OWNERSHIP_FLAG;
 
             if ( H5C_flush_single_entry(f,
-                                        primary_dxpl_id,
-                                        secondary_dxpl_id,
-                                        type,
+                                        dxpl_id,
                                         addr,
                                         flush_flags,
-                                        &dummy_first_flush,
-                                        TRUE) < 0 ) {
+                                        TRUE,
+                                        NULL) < 0 ) {
 
                 HGOTO_ERROR(H5E_CACHE, H5E_CANTUNPROTECT, FAIL, "Can't flush.")
             }
+
+#if H5C_DO_SANITY_CHECKS
+	    if ( ( take_ownership ) && ( ! was_clean ) )
+            {
+                /* we have just removed an entry from the skip list.  Thus 
+                 * we must touch up cache_ptr->slist_len_increase and
+                 * cache_ptr->slist_size_increase to keep from skewing
+                 * the sanity checks on flushes.
+                 */
+                cache_ptr->slist_len_increase -= 1;
+                cache_ptr->slist_size_increase -= (int64_t)(entry_ptr->size);
+            }
+#endif /* H5C_DO_SANITY_CHECKS */
         }
 #ifdef H5_HAVE_PARALLEL
         else if ( clear_entry ) {
 
-            /* the following first flush flag will never be used as we are
-             * calling H5C_flush_single_entry with the
-	     * H5C__FLUSH_CLEAR_ONLY_FLAG flag.  However, it is needed for
-	     * the function call.
-             */
-            hbool_t		dummy_first_flush = TRUE;
-
             /* verify that the target entry is in the cache. */
 
             H5C__SEARCH_INDEX(cache_ptr, addr, test_entry_ptr, FAIL)
@@ -5730,13 +6175,11 @@ H5C_unprotect(H5F_t *		  f,
             }
 
             if ( H5C_flush_single_entry(f,
-                                        primary_dxpl_id,
-                                        secondary_dxpl_id,
-                                        type,
+                                        dxpl_id,
                                         addr,
                                         H5C__FLUSH_CLEAR_ONLY_FLAG,
-                                        &dummy_first_flush,
-                                        TRUE) < 0 ) {
+                                        TRUE,
+                                        NULL) < 0 ) {
 
                 HGOTO_ERROR(H5E_CACHE, H5E_CANTUNPROTECT, FAIL, "Can't clear.")
             }
@@ -6392,10 +6835,8 @@ done:
  */
 static herr_t
 H5C__auto_adjust_cache_size(H5F_t * f,
-                            hid_t primary_dxpl_id,
-                            hid_t secondary_dxpl_id,
-                            hbool_t write_permitted,
-                            hbool_t * first_flush_ptr)
+                            hid_t dxpl_id,
+                            hbool_t write_permitted)
 {
     H5C_t *			cache_ptr = f->shared->cache;
     herr_t			result;
@@ -6596,13 +7037,11 @@ H5C__auto_adjust_cache_size(H5F_t * f,
                     } else {
 
                         result = H5C__autoadjust__ageout(f,
+                                                         dxpl_id,
                                                          hit_rate,
                                                          &status,
                                                          &new_max_cache_size,
-                                                         primary_dxpl_id,
-                                                         secondary_dxpl_id,
-                                                         write_permitted,
-                                                         first_flush_ptr);
+                                                         write_permitted);
 
                         if ( result != SUCCEED ) {
 
@@ -6745,13 +7184,11 @@ done:
  */
 static herr_t
 H5C__autoadjust__ageout(H5F_t * f,
+                        hid_t dxpl_id,
                         double hit_rate,
                         enum H5C_resize_status * status_ptr,
                         size_t * new_max_cache_size_ptr,
-                        hid_t primary_dxpl_id,
-                        hid_t secondary_dxpl_id,
-                        hbool_t write_permitted,
-                        hbool_t * first_flush_ptr)
+                        hbool_t write_permitted)
 {
     H5C_t *     cache_ptr = f->shared->cache;
     herr_t	result;
@@ -6792,8 +7229,7 @@ H5C__autoadjust__ageout(H5F_t * f,
         if ( cache_ptr->max_cache_size > (cache_ptr->resize_ctl).min_size ){
 
             /* evict aged out cache entries if appropriate... */
-            if(H5C__autoadjust__ageout__evict_aged_out_entries(f, primary_dxpl_id,
-                    secondary_dxpl_id, write_permitted, first_flush_ptr) < 0)
+            if(H5C__autoadjust__ageout__evict_aged_out_entries(f, dxpl_id, write_permitted) < 0)
                 HGOTO_ERROR(H5E_CACHE, H5E_SYSTEM, FAIL, "error flushing aged out entries.")
 
             /* ... and then reduce cache size if appropriate */
@@ -6990,20 +7426,32 @@ done:
  *
  * Programmer:  John Mainzer, 11/22/04
  *
+ * Changes:	Modified function to detect deletions of entries
+ *              during a scan of the LRU, and where appropriate,
+ *              restart the scan to avoid proceeding with a next
+ *              entry that is no longer in the cache.
+ *
+ *              Note the absence of checks after flushes of clean
+ *              entries.  As a second entry can only be removed by
+ *              by a call to the pre_serialize or serialize callback
+ *              of the first, and as these callbacks will not be called
+ *              on clean entries, no checks are needed.
+ *
+ *                                              JRM -- 4/6/15
+ *
  *-------------------------------------------------------------------------
  */
 static herr_t
 H5C__autoadjust__ageout__evict_aged_out_entries(H5F_t * f,
-                                                hid_t   primary_dxpl_id,
-                                                hid_t   secondary_dxpl_id,
-                                                hbool_t write_permitted,
-                                                hbool_t * first_flush_ptr)
+                                                hid_t   dxpl_id,
+                                                hbool_t write_permitted)
 {
     H5C_t *		cache_ptr = f->shared->cache;
     herr_t              result;
     size_t		eviction_size_limit;
     size_t		bytes_evicted = 0;
     hbool_t		prev_is_dirty = FALSE;
+    hbool_t             restart_scan;
     H5C_cache_entry_t * entry_ptr;
     H5C_cache_entry_t * next_ptr;
     H5C_cache_entry_t * prev_ptr;
@@ -7032,13 +7480,17 @@ H5C__autoadjust__ageout__evict_aged_out_entries(H5F_t * f,
 
     if ( write_permitted ) {
 
+        restart_scan = FALSE;
         entry_ptr = cache_ptr->LRU_tail_ptr;
 
         while ( ( entry_ptr != NULL ) &&
                 ( (entry_ptr->type)->id != H5C__EPOCH_MARKER_TYPE ) &&
                 ( bytes_evicted < eviction_size_limit ) )
         {
+            HDassert(entry_ptr->magic == H5C__H5C_CACHE_ENTRY_T_MAGIC);
             HDassert( ! (entry_ptr->is_protected) );
+            HDassert( ! (entry_ptr->is_read_only) );
+            HDassert( (entry_ptr->ro_ref_count) == 0 );
 
 	    next_ptr = entry_ptr->next;
             prev_ptr = entry_ptr->prev;
@@ -7050,26 +7502,39 @@ H5C__autoadjust__ageout__evict_aged_out_entries(H5F_t * f,
 
             if ( entry_ptr->is_dirty ) {
 
+                /* reset entries_removed_counter and
+                 * last_entry_removed_ptr prior to the call to
+                 * H5C_flush_single_entry() so that we can spot
+                 * unexpected removals of entries from the cache,
+                 * and set the restart_scan flag if proceeding
+                 * would be likely to cause us to scan an entry
+                 * that is no longer in the cache.
+                 */
+                cache_ptr->entries_removed_counter = 0;
+                cache_ptr->last_entry_removed_ptr  = NULL;
+
                 result = H5C_flush_single_entry(f,
-                                                primary_dxpl_id,
-                                                secondary_dxpl_id,
-                                                entry_ptr->type,
+                                                dxpl_id,
                                                 entry_ptr->addr,
                                                 H5C__NO_FLAGS_SET,
-                                                first_flush_ptr,
-                                                FALSE);
+                                                FALSE,
+                                                NULL);
+
+                if ( ( cache_ptr->entries_removed_counter > 1 ) ||
+                     ( cache_ptr->last_entry_removed_ptr == prev_ptr ) )
+
+                    restart_scan = TRUE;
+
             } else {
 
                 bytes_evicted += entry_ptr->size;
 
                 result = H5C_flush_single_entry(f,
-                                                primary_dxpl_id,
-                                                secondary_dxpl_id,
-                                                entry_ptr->type,
+                                                dxpl_id,
                                                 entry_ptr->addr,
                                                 H5C__FLUSH_INVALIDATE_FLAG,
-                                                first_flush_ptr,
-                                                TRUE);
+                                                TRUE,
+                                                NULL);
             }
 
             if ( result < 0 ) {
@@ -7079,30 +7544,25 @@ H5C__autoadjust__ageout__evict_aged_out_entries(H5F_t * f,
             }
 
             if ( prev_ptr != NULL ) {
-#ifndef NDEBUG
-                if ( prev_ptr->magic != H5C__H5C_CACHE_ENTRY_T_MAGIC ) {
-
-                    /* something horrible has happened to *prev_ptr --
-                     * scream and die.
-                     */
-                    HGOTO_ERROR(H5E_CACHE, H5E_SYSTEM, FAIL, \
-                                "*prev_ptr corrupt")
 
-                } else
-#endif /* NDEBUG */
-		if ( ( prev_ptr->is_dirty != prev_is_dirty )
-                         ||
-                         ( prev_ptr->next != next_ptr )
-                         ||
-                         ( prev_ptr->is_protected )
-                         ||
-                         ( prev_ptr->is_pinned ) ) {
+		if ( ( restart_scan )
+                     ||
+                     ( prev_ptr->is_dirty != prev_is_dirty )
+                     ||
+                     ( prev_ptr->next != next_ptr )
+                     ||
+                     ( prev_ptr->is_protected )
+                     ||
+                     ( prev_ptr->is_pinned ) ) {
 
                     /* something has happened to the LRU -- start over
 		     * from the tail.
                      */
+                    restart_scan = FALSE;
                     entry_ptr = cache_ptr->LRU_tail_ptr;
 
+		    H5C__UPDATE_STATS_FOR_LRU_SCAN_RESTART(cache_ptr)
+
                 } else {
 
                     entry_ptr = prev_ptr;
@@ -7161,13 +7621,11 @@ H5C__autoadjust__ageout__evict_aged_out_entries(H5F_t * f,
             if ( ! (entry_ptr->is_dirty) ) {
 
                 result = H5C_flush_single_entry(f,
-                                                primary_dxpl_id,
-                                                secondary_dxpl_id,
-                                                entry_ptr->type,
+                                                dxpl_id,
                                                 entry_ptr->addr,
                                                 H5C__FLUSH_INVALIDATE_FLAG,
-                                                first_flush_ptr,
-                                                TRUE);
+                                                TRUE,
+                                                NULL);
 
                 if ( result < 0 ) {
 
@@ -7177,6 +7635,10 @@ H5C__autoadjust__ageout__evict_aged_out_entries(H5F_t * f,
             }
             /* just skip the entry if it is dirty, as we can't do
              * anything with it now since we can't write.
+	     *
+	     * Since all entries are clean, serialize() will not be called,
+	     * and thus we needn't test to see if the LRU has been changed
+	     * out from under us.
              */
 
             entry_ptr = prev_ptr;
@@ -7640,17 +8102,45 @@ done:
  * Programmer:  John Mainzer
  *		3/24/065
  *
+ * Changes:     Modified function to test for slist chamges in
+ *              pre_serialize and serialize callbacks, and re-start
+ *              scans through the slist when such changes occur.
+ *
+ *              This has been a potential problem for some time,
+ *              and there has been code in this function to deal
+ *              with elements of this issue.  However the shift
+ *              to the V3 cache in combination with the activities
+ *              of some of the cache clients (in particular the
+ *              free space manager and the fractal heap) have
+ *              made this re-work necessary in H5C_flush_cache.
+ *
+ *		At present, this issue doesn't seem to be causing problems
+ *		in H5C_flush_invalidate_cache().  However, it seems 
+ *		prudent to port the H5C_flush_cache changes to this 
+ *		function as well.
+ *
+ *                                              JRM -- 12/14/14
+ *
+ *		Added code to track entry size change during flush single
+ *		entry.  This didn't used to be a problem, as the entry 
+ *		was largely removed from the cache data structures before
+ *		the flush proper.  However, re-entrant calls to the cache
+ *		in the parallel case required a re-factoring of the 
+ *		H5C_flush_single_entry() function to keep entries fully
+ *		in the cache until after the pre-serialize and serialize
+ *		calls.
+ *                                               JRM -- 12/25/14
+ *
  *-------------------------------------------------------------------------
  */
 static herr_t
-H5C_flush_invalidate_cache(H5F_t * f,
-                           hid_t    primary_dxpl_id,
-                           hid_t    secondary_dxpl_id,
+H5C_flush_invalidate_cache(const H5F_t * f,
+                           hid_t    dxpl_id,
 			   unsigned flags)
 {
     H5C_t *		cache_ptr = f->shared->cache;
     herr_t              status;
-    hbool_t		first_flush = TRUE;
+    hbool_t             restart_slist_scan;
     int32_t		protected_entries = 0;
     int32_t		i;
     int32_t		cur_pel_len;
@@ -7661,10 +8151,14 @@ H5C_flush_invalidate_cache(H5F_t * f,
     H5C_cache_entry_t *	entry_ptr = NULL;
     H5C_cache_entry_t *	next_entry_ptr = NULL;
 #if H5C_DO_SANITY_CHECKS
-    int64_t		actual_slist_len = 0;
+    int64_t		flushed_slist_len = 0;
     int64_t		initial_slist_len = 0;
-    size_t              actual_slist_size = 0;
+    int64_t             flushed_slist_size = 0;
     size_t              initial_slist_size = 0;
+    int64_t		entry_size_change;
+    int64_t	      * entry_size_change_ptr = &entry_size_change;
+#else /* H5C_DO_SANITY_CHECKS */
+    int64_t           * entry_size_change_ptr = NULL;
 #endif /* H5C_DO_SANITY_CHECKS */
     herr_t		ret_value = SUCCEED;
 
@@ -7743,25 +8237,6 @@ H5C_flush_invalidate_cache(H5F_t * f,
              * may be created by the flush call backs.  Thus it is possible
              * that the slist will not be empty after we finish the scan.
              */
-            if ( cache_ptr->slist_len == 0 ) {
-
-                node_ptr = NULL;
-                HDassert( cache_ptr->slist_size == 0 );
-
-            } else {
-
-                /* Start at beginning of skip list each time */
-                node_ptr = H5SL_first(cache_ptr->slist_ptr);
-                HDassert( node_ptr != NULL );
-
-                /* Get cache entry for this node */
-                next_entry_ptr = (H5C_cache_entry_t *)H5SL_item(node_ptr);
-                if ( NULL == next_entry_ptr )
-                    HGOTO_ERROR(H5E_CACHE, H5E_SYSTEM, FAIL, "next_entry_ptr == NULL ?!?!")
-                HDassert( next_entry_ptr->magic == H5C__H5C_CACHE_ENTRY_T_MAGIC );
-                HDassert( next_entry_ptr->is_dirty );
-                HDassert( next_entry_ptr->in_slist );
-            }
 
 #if H5C_DO_SANITY_CHECKS
             /* Depending on circumstances, H5C_flush_single_entry() will
@@ -7785,63 +8260,80 @@ H5C_flush_invalidate_cache(H5F_t * f,
             cache_ptr->slist_len_increase = 0;
             cache_ptr->slist_size_increase = 0;
 
-            /* Finally, reset the actual_slist_len and actual_slist_size
+            /* Finally, reset the flushed_slist_len and flushed_slist_size
              * fields to zero, as these fields are used to accumulate
              * the slist lenght and size that we see as we scan through
              * the slist.
              */
-            actual_slist_len = 0;
-            actual_slist_size = 0;
+            flushed_slist_len = 0;
+            flushed_slist_size = 0;
 #endif /* H5C_DO_SANITY_CHECKS */
 
-            while ( node_ptr != NULL )
+            /* set the cache_ptr->slist_change_in_pre_serialize and
+             * cache_ptr->slist_change_in_serialize to false.
+             *
+             * These flags are set to TRUE by H5C_flush_single_entry if the
+             * slist is modified by a pre_serialize or serialize call 
+             * respectively.
+             *
+             * H5C_flush_invalidate_cache() uses these flags to detect any 
+             * modifications to the slist that might corrupt the scan of 
+             * the slist -- and restart the scan in this event.
+             */
+            cache_ptr->slist_change_in_pre_serialize = FALSE;
+            cache_ptr->slist_change_in_serialize = FALSE;
+
+            /* this done, start the scan of the slist */
+
+            restart_slist_scan = TRUE;
+
+            while ( ( restart_slist_scan ) || ( node_ptr != NULL ) )
             {
-                entry_ptr = next_entry_ptr;
+                if ( restart_slist_scan )
+                {
+                    restart_slist_scan = FALSE;
 
-                /* With the advent of the fractal heap, it is possible
-                 * that the flush callback will dirty and/or resize
-                 * other entries in the cache.  In particular, while
-                 * Quincey has promised me that this will never happen,
-                 * it is possible that the flush callback for an
-                 * entry may protect an entry that is not in the cache,
-                 * perhaps causing the cache to flush and possibly
-                 * evict the entry associated with node_ptr to make
-                 * space for the new entry.
-                 *
-                 * Thus we do a bit of extra sanity checking on entry_ptr,
-                 * and break out of this scan of the skip list if we
-                 * detect major problems.  We have a bit of leaway on the
-                 * number of passes though the skip list, so this shouldn't
-                 * be an issue in the flush in and of itself, as it should
-                 * be all but impossible for this to happen more than once
-                 * in any flush.
-                 *
-                 * Observe that that breaking out of the scan early
-                 * shouldn't break the sanity checks just after the end
-                 * of this while loop.
-                 *
-                 * If an entry has merely been marked clean and removed from
-                 * the s-list, we simply break out of the scan.
-                 *
-                 * If the entry has been evicted, we flag an error and
-                 * exit.
-                 */
-#ifndef NDEBUG
-                if ( entry_ptr->magic != H5C__H5C_CACHE_ENTRY_T_MAGIC ) {
+                    /* Start at beginning of skip list */
+                    node_ptr = H5SL_first(cache_ptr->slist_ptr);
 
-                    HGOTO_ERROR(H5E_CACHE, H5E_SYSTEM, FAIL, "entry_ptr->magic is invalid ?!?!")
+                    if ( node_ptr == NULL )
+                    {
+                        /* the slist is empty -- break out of inner loop */
+                        break;
+                    }
+                    HDassert( node_ptr != NULL );
 
-                } else
-#endif /* NDEBUG */
-                if ( ( ! entry_ptr->is_dirty ) ||
-                     ( ! entry_ptr->in_slist ) ) {
+                    /* Get cache entry for this node */
+                    next_entry_ptr = (H5C_cache_entry_t *)H5SL_item(node_ptr);
 
-                    /* the s-list has been modified out from under us.
-                     * break out of the loop.
-                     */
-                    goto end_of_inner_loop;;
+                    if(NULL == next_entry_ptr)
+                        HGOTO_ERROR(H5E_CACHE, H5E_SYSTEM, FAIL, \
+                                    "next_entry_ptr == NULL ?!?!")
+
+                    HDassert( next_entry_ptr->magic == \
+                              H5C__H5C_CACHE_ENTRY_T_MAGIC );
+                    HDassert( next_entry_ptr->is_dirty );
+                    HDassert( next_entry_ptr->in_slist );
                 }
 
+                entry_ptr = next_entry_ptr;
+
+                /* It is possible that entries will be dirtied, resized, 
+                 * flushed, or removed from the cache via the take ownership
+                 * flag as the result of pre_serialize or serialized callbacks. 
+                 * 
+                 * This in turn can corrupt the scan through the slist.
+                 *
+                 * We test for slist modifications in the pre_serialize 
+                 * and serialize callbacks, and restart the scan of the 
+                 * slist if we find them.  However, best we do some extra
+                 * sanity checking just in case.
+                 */
+
+                HDassert( entry_ptr->magic == H5C__H5C_CACHE_ENTRY_T_MAGIC );
+                HDassert( entry_ptr->in_slist );
+                HDassert( entry_ptr->is_dirty );
+
                 /* increment node pointer now, before we delete its target
                  * from the slist.
                  */
@@ -7854,6 +8346,7 @@ H5C_flush_invalidate_cache(H5F_t * f,
                     HDassert( next_entry_ptr->magic == H5C__H5C_CACHE_ENTRY_T_MAGIC );
                     HDassert( next_entry_ptr->is_dirty );
                     HDassert( next_entry_ptr->in_slist );
+                    HDassert( entry_ptr != next_entry_ptr );
                 } else {
                     next_entry_ptr = NULL;
 	        }
@@ -7877,21 +8370,6 @@ H5C_flush_invalidate_cache(H5F_t * f,
                        ( cache_ptr->num_last_entries >=
                          cache_ptr->slist_len ) ) ) {
 
-#if H5C_DO_SANITY_CHECKS
-                    /* update actual_slist_len & actual_slist_size before
-                     * the flush.  Note that the entry will be removed
-                     * from the slist after the flush, and thus may be
-                     * resized by the flush callback.  This is OK, as
-                     * we will catch the size delta in
-                     * cache_ptr->slist_size_increase.
-                     *
-                     * Note that we include pinned entries in this count, even
-                     * though we will not actually flush them.
-                     */
-                    actual_slist_len++;
-                    actual_slist_size += entry_ptr->size;
-#endif /* H5C_DO_SANITY_CHECKS */
-
                     if ( entry_ptr->is_protected ) {
 
                         /* we have major problems -- but lets flush
@@ -7907,14 +8385,26 @@ H5C_flush_invalidate_cache(H5F_t * f,
                          * as pinned entries can't be evicted.
                          */
                         if(entry_ptr->flush_dep_height == curr_flush_dep_height ) {
+#if H5C_DO_SANITY_CHECKS
+                            /* update flushed_slist_len & flushed_slist_size 
+                             * before the flush.  Note that the entry will 
+                             * be removed from the slist after the flush, 
+                             * and thus may be resized by the flush callback.
+                             * This is OK, as we will catch the size delta in
+                             * cache_ptr->slist_size_increase.
+                             *
+                             */
+                            flushed_slist_len++;
+                            flushed_slist_size += (int64_t)entry_ptr->size;
+		            entry_size_change = 0;
+#endif /* H5C_DO_SANITY_CHECKS */
+
                             status = H5C_flush_single_entry(f,
-                                                            primary_dxpl_id,
-                                                            secondary_dxpl_id,
-                                                            NULL,
+                                                            dxpl_id,
                                                             entry_ptr->addr,
                                                             H5C__NO_FLAGS_SET,
-                                                            &first_flush,
-                                                            FALSE);
+                                                            FALSE,
+                                                            entry_size_change_ptr);
                             if ( status < 0 ) {
 
                                 /* This shouldn't happen -- if it does, we 
@@ -7924,7 +8414,32 @@ H5C_flush_invalidate_cache(H5F_t * f,
                                 HGOTO_ERROR(H5E_CACHE, H5E_CANTFLUSH, FAIL, \
                                             "dirty pinned entry flush failed.")
                             } /* end if */
+
+#if H5C_DO_SANITY_CHECKS
+                            /* entry size may have changed during the flush.
+                             * Update flushed_slist_size to account for this.
+                             */
+                            flushed_slist_size += entry_size_change;
+#endif /* H5C_DO_SANITY_CHECKS */
+
                             flushed_during_dep_loop = TRUE;
+
+                            if ( ( cache_ptr->slist_change_in_serialize ) ||
+                                 ( cache_ptr->slist_change_in_pre_serialize ) )
+                            {
+                                /* The slist has been modified by something
+                                 * other than the simple removal of the
+                                 * of the flushed entry after the flush.
+                                 *
+                                 * This has the potential to corrupt the
+                                 * scan through the slist, so restart it.
+                                 */
+                                restart_slist_scan = TRUE;
+                                cache_ptr->slist_change_in_pre_serialize 
+                                    = FALSE;
+                                cache_ptr->slist_change_in_serialize = FALSE;
+				H5C__UPDATE_STATS_FOR_SLIST_SCAN_RESTART(cache_ptr);
+                            }
                         } /* end if */
                         else if(entry_ptr->flush_dep_height < curr_flush_dep_height)
                             /* This shouldn't happen -- if it does, just scream and die.  */
@@ -7932,15 +8447,26 @@ H5C_flush_invalidate_cache(H5F_t * f,
                     } /* end if */
                     else {
                         if(entry_ptr->flush_dep_height == curr_flush_dep_height ){
+#if H5C_DO_SANITY_CHECKS
+                            /* update flushed_slist_len & flushed_slist_size 
+                             * before the flush.  Note that the entry will 
+                             * be removed from the slist after the flush, 
+                             * and thus may be resized by the flush callback.
+                             * This is OK, as we will catch the size delta in
+                             * cache_ptr->slist_size_increase.
+                             *
+                             */
+                            flushed_slist_len++;
+                            flushed_slist_size += (int64_t)entry_ptr->size;
+		            entry_size_change = 0;
+#endif /* H5C_DO_SANITY_CHECKS */
 
                             status = H5C_flush_single_entry(f,
-                                                            primary_dxpl_id,
-                                                            secondary_dxpl_id,
-                                                            NULL,
-                                                            entry_ptr->addr,
-                                                            (cooked_flags | H5C__FLUSH_INVALIDATE_FLAG),
-                                                            &first_flush,
-                                                            TRUE);
+                                    dxpl_id,
+                                    entry_ptr->addr,
+                                    (cooked_flags | H5C__FLUSH_INVALIDATE_FLAG),
+                                    TRUE,
+                                    entry_size_change_ptr);
                             if ( status < 0 ) {
 
                                 /* This shouldn't happen -- if it does, we 
@@ -7950,7 +8476,32 @@ H5C_flush_invalidate_cache(H5F_t * f,
                                 HGOTO_ERROR(H5E_CACHE, H5E_CANTFLUSH, FAIL, \
                                             "dirty entry flush destroy failed.")
                             } /* end if */
+
+#if H5C_DO_SANITY_CHECKS
+                            /* entry size may have changed during the flush.
+                             * Update flushed_slist_size to account for this.
+                             */
+                            flushed_slist_size += entry_size_change;
+#endif /* H5C_DO_SANITY_CHECKS */
+
                             flushed_during_dep_loop = TRUE;
+
+                            if ((cache_ptr->slist_change_in_serialize) ||
+                                (cache_ptr->slist_change_in_pre_serialize))
+                            {
+                                /* The slist has been modified by something
+                                 * other than the simple removal of the
+                                 * of the flushed entry after the flush.
+                                 *
+                                 * This has the potential to corrupt the
+                                 * scan through the slist, so restart it.
+                                 */
+                                restart_slist_scan = TRUE;
+                                cache_ptr->slist_change_in_pre_serialize
+                                    = FALSE;
+                                cache_ptr->slist_change_in_serialize = FALSE;
+				H5C__UPDATE_STATS_FOR_SLIST_SCAN_RESTART(cache_ptr)
+                            }
                         } /* end if */
                         else if(entry_ptr->flush_dep_height < curr_flush_dep_height)
                             /* This shouldn't happen -- if it does, just scream and die.  */
@@ -7971,11 +8522,10 @@ H5C_flush_invalidate_cache(H5F_t * f,
 
             if ( node_ptr == NULL ) {
 
-                HDassert( (actual_slist_len + cache_ptr->slist_len) ==
+                HDassert( (flushed_slist_len + cache_ptr->slist_len) ==
                           (initial_slist_len + cache_ptr->slist_len_increase) );
-                HDassert( (actual_slist_size + cache_ptr->slist_size) ==
-                          (initial_slist_size + 
-                           (size_t)(cache_ptr->slist_size_increase)) );
+                HDassert( (flushed_slist_size + (int64_t)cache_ptr->slist_size) ==
+                          ((int64_t)initial_slist_size + cache_ptr->slist_size_increase) );
             }
 #endif /* H5C_DO_SANITY_CHECKS */
 
@@ -7997,9 +8547,7 @@ H5C_flush_invalidate_cache(H5F_t * f,
                 while ( next_entry_ptr != NULL )
                 {
                     entry_ptr = next_entry_ptr;
-#ifndef NDEBUG
                     HDassert( entry_ptr->magic == H5C__H5C_CACHE_ENTRY_T_MAGIC );
-#endif /* NDEBUG */
 
                     next_entry_ptr = entry_ptr->ht_next;
                     HDassert ( ( next_entry_ptr == NULL ) ||
@@ -8028,14 +8576,40 @@ H5C_flush_invalidate_cache(H5F_t * f,
                              * If we can, go ahead and flush.
                              */
                             if(entry_ptr->flush_dep_height == curr_flush_dep_height ){
+				/* if *entry_ptr is dirty, it is possible 
+                                 * that one or more other entries may be 
+                                 * either removed from the cache, loaded 
+                                 * into the cache, or moved to a new location
+                                 * in the file as a side effect of the flush.
+                                 *
+                                 * If this happens, and one of the target 
+                                 * entries happens to be the next entry in 
+                                 * the hash bucket, we could find ourselves 
+				 * either find ourselves either scanning a 
+                                 * non-existant entry, scanning through a 
+                                 * different bucket, or skipping an entry.
+                                 *
+                                 * Neither of these are good, so restart the 
+                                 * the scan at the head of the hash bucket 
+                                 * after the flush if *entry_ptr was dirty,
+                                 * on the off chance that the next entry was
+                                 * a target.
+                                 *
+                                 * This is not as inefficient at it might seem,
+                                 * as hash buckets typically have at most two
+                                 * or three entries.
+                                 */
+                                hbool_t entry_was_dirty;
+
+                                entry_was_dirty = entry_ptr->is_dirty;
+
                                 status = H5C_flush_single_entry(f,
-                                                                primary_dxpl_id,
-                                                                secondary_dxpl_id,
-                                                                NULL,
-                                                                entry_ptr->addr,
-                                                                (cooked_flags | H5C__FLUSH_INVALIDATE_FLAG),
-                                                                &first_flush,
-                                                                TRUE);
+                                    dxpl_id,
+                                    entry_ptr->addr,
+                                    (cooked_flags | H5C__FLUSH_INVALIDATE_FLAG),
+                                    TRUE,
+                                    NULL);
+
                                 if ( status < 0 ) {
 
                                     /* This shouldn't happen -- if it does, 
@@ -8045,6 +8619,17 @@ H5C_flush_invalidate_cache(H5F_t * f,
                                     HGOTO_ERROR(H5E_CACHE, H5E_CANTFLUSH, FAIL, \
                                                 "Entry flush destroy failed.")
                                 }
+
+				if ( entry_was_dirty ) {
+
+                                    /* update stats for hash bucket scan
+                                     * restart here.
+                                     *                   -- JRM 
+                                     */
+                                    next_entry_ptr = cache_ptr->index[i];
+				    H5C__UPDATE_STATS_FOR_HASH_BUCKET_SCAN_RESTART(cache_ptr)
+                                }
+
                                 flushed_during_dep_loop = TRUE;
                             } /* end if */
                             else if(entry_ptr->flush_dep_height < curr_flush_dep_height)
@@ -8060,7 +8645,7 @@ H5C_flush_invalidate_cache(H5F_t * f,
                      * of pinned entries from pass to pass.  If it stops
                      * shrinking before it hits zero, we scream and die.
                      */
-                    /* if the flush function on the entry we last evicted
+                    /* if the serialize function on the entry we last evicted
                      * loaded an entry into cache (as Quincey has promised me
                      * it never will), and if the cache was full, it is
                      * possible that *next_entry_ptr was flushed or evicted.
@@ -8069,8 +8654,13 @@ H5C_flush_invalidate_cache(H5F_t * f,
                      * test is triggred, we are accessing a deallocated piece
                      * of dynamically allocated memory, so we just scream and
                      * die.
+                     *
+                     * Update: The code to restart the scan after flushes
+                     *         of dirty entries should make it impossible 
+                     *         to satisfy the following test.  Leave it in
+                     *         in case I am wrong.
+                     *                                    -- JRM
                      */
-#ifndef NDEBUG
                     if ( ( next_entry_ptr != NULL ) &&
                          ( next_entry_ptr->magic !=
                            H5C__H5C_CACHE_ENTRY_T_MAGIC ) ) {
@@ -8081,7 +8671,6 @@ H5C_flush_invalidate_cache(H5F_t * f,
                         HGOTO_ERROR(H5E_CACHE, H5E_SYSTEM, FAIL, \
                                     "next_entry_ptr->magic is invalid?!?!?.")
                     }
-#endif /* NDEBUG */
                 } /* end while loop scanning hash table bin */
             } /* end for loop scanning hash table */
 
@@ -8099,7 +8688,6 @@ H5C_flush_invalidate_cache(H5F_t * f,
                 curr_flush_dep_height++;
 
         } /* end while loop over flush dependency heights */
-end_of_inner_loop:
 
 	old_pel_len = cur_pel_len;
 	cur_pel_len = cache_ptr->pel_len;
@@ -8177,22 +8765,9 @@ done:
  *		Attempts to flush a protected entry will result in an
  *		error.
  *
- *		*first_flush_ptr should be true if only one
- *		flush is contemplated before the next load, or if this
- *		is the first of a sequence of flushes that will be
- *		completed before the next load.  *first_flush_ptr is set
- *		to false if a flush actually takes place, and should be
- *		left false until the end of the sequence.
- *
- *		The primary_dxpl_id is used if *first_flush_ptr is TRUE
- *		on entry, and a flush actually takes place.  The
- *		secondary_dxpl_id is used in any subsequent flush where
- *		*first_flush_ptr is FALSE on entry.
- *
  *		If the H5C__FLUSH_INVALIDATE_FLAG flag is set, the entry will
- *		be cleared and not flushed -- in the case *first_flush_ptr,
- *		primary_dxpl_id, and secondary_dxpl_id are all irrelevent,
- *		and the call can't be part of a sequence of flushes.
+ *		be cleared and not flushed, and the call can't be part of a
+ *              sequence of flushes.
  *
  *		If the caller knows the address of the skip list node at
  *		which the target entry resides, it can avoid a lookup
@@ -8209,26 +8784,57 @@ done:
  *
  * Programmer:  John Mainzer, 5/5/04
  *
+ * Changes:	Refactored function to remove the type_ptr parameter.
+ *
+ *						JRM -- 8/7/14
+ *
+ *              Added code to check for slist changes in pre_serialize and
+ *              serialize calls, and set 
+ *              cache_ptr->slist_change_in_pre_serialize and 
+ *		cache_ptr->slist_change_in_serialize as appropriate.
+ *
+ *                                              JRM -- 12/13/14
+ *
+ *		Refactored function to delay all modifications of the 
+ *		metadata cache data structures until after any calls 
+ *		to the pre-serialize or serialize callbacks.  
+ *
+ *		Need to do this, as some pre-serialize or serialize 
+ *		calls result in calls to the metadata cache and 
+ *		modifications to its data structures.  Thus, at the
+ *		time of any such call, the target entry flags and 
+ *		the metadata cache must all be consistant.
+ *
+ *		Also added the entry_size_change_ptr parameter, which 
+ *              allows the function to report back any change in the size 
+ *		of the entry during the flush.  Such size changes may 
+ *		occur during the pre-serialize callback.
+ *
+ *						JRM -- 12/24/14
+ *
  *-------------------------------------------------------------------------
  */
 static herr_t
-H5C_flush_single_entry(H5F_t *	   	   f,
-                       hid_t 		   primary_dxpl_id,
-                       hid_t 		   secondary_dxpl_id,
-                       const H5C_class_t * type_ptr,
+H5C_flush_single_entry(const H5F_t *	   f,
+                       hid_t 		   dxpl_id,
                        haddr_t		   addr,
                        unsigned	     	   flags,
-                       hbool_t *	   first_flush_ptr,
-                       hbool_t		   del_entry_from_slist_on_destroy)
+                       hbool_t		   del_entry_from_slist_on_destroy,
+                       int64_t *           entry_size_change_ptr)
 {
     H5C_t *	     	cache_ptr = f->shared->cache;
     hbool_t		destroy;		/* external flag */
     hbool_t		clear_only;		/* external flag */
+    hbool_t		free_file_space;	/* external flag */
     hbool_t		take_ownership;		/* external flag */
+    hbool_t		write_entry;		/* internal flag */
+    hbool_t		destroy_entry;		/* internal flag */
     hbool_t		was_dirty;
-    hbool_t		destroy_entry;
     herr_t		status;
-    unsigned		flush_flags = H5C_CALLBACK__NO_FLAGS_SET;
+    haddr_t		new_addr = HADDR_UNDEF;
+    haddr_t		old_addr = HADDR_UNDEF;
+    size_t		new_len = 0;
+    size_t		new_compressed_len = 0;
     H5C_cache_entry_t * entry_ptr = NULL;
     herr_t		ret_value = SUCCEED;      /* Return value */
 
@@ -8238,11 +8844,15 @@ H5C_flush_single_entry(H5F_t *	   	   f,
     HDassert( cache_ptr );
     HDassert( cache_ptr->magic == H5C__H5C_T_MAGIC );
     HDassert( H5F_addr_defined(addr) );
-    HDassert( first_flush_ptr );
+
+    /* If defined, initialize *entry_size_change_ptr to 0 */
+    if(entry_size_change_ptr != NULL)
+        *entry_size_change_ptr = 0;
 
     /* setup external flags from the flags parameter */
     destroy                = ((flags & H5C__FLUSH_INVALIDATE_FLAG) != 0);
     clear_only             = ((flags & H5C__FLUSH_CLEAR_ONLY_FLAG) != 0);
+    free_file_space        = ((flags & H5C__FREE_FILE_SPACE_FLAG) != 0);
     take_ownership         = ((flags & H5C__TAKE_OWNERSHIP_FLAG) != 0);
 
     /* Set the flag for destroying the entry, based on the 'take ownership'
@@ -8256,6 +8866,14 @@ H5C_flush_single_entry(H5F_t *	   	   f,
     /* attempt to find the target entry in the hash table */
     H5C__SEARCH_INDEX(cache_ptr, addr, entry_ptr, FAIL)
 
+    /* we will write the entry to disk if it exists, is dirty, and if the 
+     * clear only flag is not set.
+     */
+    if ( ( entry_ptr != NULL ) && ( entry_ptr->is_dirty ) && ( ! clear_only ) )
+        write_entry = TRUE;
+    else
+        write_entry = FALSE;
+
     /* run initial sanity checks */
 #if H5C_DO_SANITY_CHECKS
     if ( entry_ptr != NULL ) {
@@ -8264,6 +8882,8 @@ H5C_flush_single_entry(H5F_t *	   	   f,
 
         if ( entry_ptr->in_slist ) {
 
+	    HDassert(entry_ptr->is_dirty);
+
             if ( ( ( entry_ptr->flush_marker ) && ( ! entry_ptr->is_dirty ) ) ||
                  ( entry_ptr->addr != addr ) ) {
 
@@ -8272,6 +8892,10 @@ H5C_flush_single_entry(H5F_t *	   	   f,
             }
         } else {
 
+	    HDassert(!entry_ptr->is_dirty);
+	    HDassert(!entry_ptr->flush_marker);
+	    HDassert(entry_ptr->addr == addr);
+
             if ( ( entry_ptr->is_dirty ) ||
                  ( entry_ptr->flush_marker ) ||
                  ( entry_ptr->addr != addr ) ) {
@@ -8285,22 +8909,32 @@ H5C_flush_single_entry(H5F_t *	   	   f,
 
     if ( ( entry_ptr != NULL ) && ( entry_ptr->is_protected ) )
     {
+	HDassert(!entry_ptr->is_protected);
 
         /* Attempt to flush a protected entry -- scream and die. */
         HGOTO_ERROR(H5E_CACHE, H5E_PROTECT, FAIL, \
                     "Attempt to flush a protected entry.")
     }
 
-    if ( ( entry_ptr != NULL ) &&
-         ( ( type_ptr == NULL ) || ( type_ptr->id == entry_ptr->type->id ) ) )
+    /* if the entry exists, set entry_ptr->flush_in_progress = TRUE
+     * and set entry_ptr->flush_marker = FALSE
+     *
+     * in the parallel case, do some sanity checking in passing.
+     */
+    if ( entry_ptr != NULL )
     {
         /* we have work to do */
+	HDassert(entry_ptr->type);
+
+        was_dirty = entry_ptr->is_dirty;  /* needed later for logging */
 
 	/* We will set flush_in_progress back to FALSE at the end if the
 	 * entry still exists at that point.
 	 */
 	entry_ptr->flush_in_progress = TRUE;
 
+        entry_ptr->flush_marker = FALSE;
+
 #ifdef H5_HAVE_PARALLEL
 #ifndef NDEBUG
         /* If MPI based VFD is used, do special parallel I/O sanity checks.
@@ -8314,7 +8948,7 @@ H5C_flush_single_entry(H5F_t *	   	   f,
             unsigned coll_meta;         /* Collective metadata write flag */
 
             /* Get the dataset transfer property list */
-            if(NULL == (dxpl = H5I_object(primary_dxpl_id)))
+            if(NULL == (dxpl = H5I_object(dxpl_id)))
                 HGOTO_ERROR(H5E_CACHE, H5E_BADTYPE, FAIL, "not a dataset transfer property list")
 
             /* Get the collective metadata write property */
@@ -8326,273 +8960,644 @@ H5C_flush_single_entry(H5F_t *	   	   f,
         } /* end if */
 #endif /* NDEBUG */
 #endif /* H5_HAVE_PARALLEL */
+    }
 
-        was_dirty = entry_ptr->is_dirty;
-
-        entry_ptr->flush_marker = FALSE;
-
-        if ( clear_only ) {
-            H5C__UPDATE_STATS_FOR_CLEAR(cache_ptr, entry_ptr)
-        } else {
-            H5C__UPDATE_STATS_FOR_FLUSH(cache_ptr, entry_ptr)
-        }
-
-        if ( destroy ) {
-            H5C__UPDATE_STATS_FOR_EVICTION(cache_ptr, entry_ptr)
-        }
+    if ( ( entry_ptr != NULL ) && ( write_entry ) )
+    {
+        /* serialize the entry if necessary, and then write it to disk. */
 
-        /* If the entry's type has a 'notify' callback and the entry is about
-         * to be removed from the cache, send a 'before eviction' notice while
-         * the entry is still fully integrated in the cache.
-         */
-        if(destroy) {
-            if(entry_ptr->type->notify &&
-                    (entry_ptr->type->notify)(H5C_NOTIFY_ACTION_BEFORE_EVICT, entry_ptr) < 0)
-                HGOTO_ERROR(H5E_CACHE, H5E_CANTNOTIFY, FAIL, "can't notify client about entry to evict")
-        } /* end if */
+        unsigned serialize_flags = H5C__SERIALIZE_NO_FLAGS_SET;
 
-        /* Always remove the entry from the hash table on a destroy.  On a
-         * flush with destroy, it is cheaper to discard the skip list all at
-         * once rather than remove the entries one by one, so we only delete
-         * from the slist only if requested.
+	/* The entry is dirty, and we are doing either a flush,
+	 * or a flush destroy.  In either case, serialize the
+	 * entry and write it to disk.
          *
-         * We must do deletions now as the callback routines will free the
-         * entry if destroy is true.
+         * Note that this may cause the entry to be re-sized and/or
+         * moved in the cache.  
 	 *
-	 * Note that it is possible that the entry will be moved during
-	 * its call to flush.  This will upset H5C_move_entry() if we
-	 * don't tell it that it doesn't have to worry about updating the
-	 * index and SLIST.  Use the destroy_in_progress field for this
-	 * purpose.
+         * As we will not update the metadata cache's data structures 
+         * until we we finish the write, we must touch up these 
+         * data structures for size and location changes even if we 
+         * are about to delete the entry from the cache (i.e. on a 
+         * flush destroy).
          */
-        if ( destroy ) {
 
-            entry_ptr->destroy_in_progress = TRUE;
+        HDassert(entry_ptr->is_dirty);
 
-            H5C__DELETE_FROM_INDEX(cache_ptr, entry_ptr)
+#if H5C_DO_SANITY_CHECKS
+        if ( ( cache_ptr->check_write_permitted == NULL ) && 
+             ( !(cache_ptr->write_permitted) ) )
 
-            if ( ( entry_ptr->in_slist ) &&
-                 ( del_entry_from_slist_on_destroy ) ) {
+            HGOTO_ERROR(H5E_CACHE, H5E_SYSTEM, FAIL, \
+                       "Write when writes are always forbidden!?!?!")
+#endif /* H5C_DO_SANITY_CHECKS */
 
-                H5C__REMOVE_ENTRY_FROM_SLIST(cache_ptr, entry_ptr)
+        if ( NULL == entry_ptr->image_ptr ) 
+        {
+            size_t image_size;
+
+            if ( entry_ptr->compressed )
+                image_size = entry_ptr->compressed_size;
+            else
+                image_size = entry_ptr->size;
+
+            HDassert(image_size > 0);
+
+            entry_ptr->image_ptr = 
+                H5MM_malloc(image_size + H5C_IMAGE_EXTRA_SPACE);
+
+            if ( NULL == entry_ptr->image_ptr) 
+            {
+                HGOTO_ERROR(H5E_CACHE, H5E_CANTALLOC, FAIL, \
+                       "memory allocation failed for on disk image buffer")
             }
-        }
+#if H5C_DO_MEMORY_SANITY_CHECKS
 
-        /* Update the replacement policy for the flush or eviction.
-         * Again, do this now so we don't have to reference freed
-         * memory in the destroy case.
-         */
-        if ( destroy ) { /* AKA eviction */
+            HDmemcpy(((uint8_t *)entry_ptr->image_ptr) + image_size, 
+                     H5C_IMAGE_SANITY_VALUE, H5C_IMAGE_EXTRA_SPACE);
 
-            H5C__UPDATE_RP_FOR_EVICTION(cache_ptr, entry_ptr, FAIL)
+#endif /* H5C_DO_MEMORY_SANITY_CHECKS */
 
-        } else {
+        } /* end if */
 
-            H5C__UPDATE_RP_FOR_FLUSH(cache_ptr, entry_ptr, FAIL)
-        }
+        if ( ! (entry_ptr->image_up_to_date) ) 
+        {
+            /* reset cache_ptr->slist_changed so we can detect slist
+             * modifications in the pre_serialize call.
+             */
+            cache_ptr->slist_changed = FALSE;
+
+            /* make note of the entry's current address */
+            old_addr = entry_ptr->addr;
+
+            /* Call client's pre-serialize callback, if there's one */
+            if ( ( entry_ptr->type->pre_serialize != NULL ) && 
+                 ( (entry_ptr->type->pre_serialize)(f, dxpl_id, 
+                                                    (void *)entry_ptr,
+                                                    entry_ptr->addr, 
+                                                    entry_ptr->size,
+						    entry_ptr->compressed_size,
+                                                    &new_addr, &new_len, 
+                                                    &new_compressed_len,
+                                                    &serialize_flags) < 0 ) )
+            {
+                HGOTO_ERROR(H5E_CACHE, H5E_CANTFLUSH, FAIL, \
+                            "unable to pre-serialize entry")
+            }
 
-        /* Clear the dirty flag only, if requested */
-        if ( clear_only ) {
+            /* set cache_ptr->slist_change_in_pre_serialize if the 
+             * slist was modified.
+             */
+            if ( cache_ptr->slist_changed )
+                cache_ptr->slist_change_in_pre_serialize = TRUE;
 
-	    if ( destroy ) {
-#ifndef NDEBUG
-		/* we are about to call the clear callback with the
-		 * destroy flag set -- this will result in *entry_ptr
-		 * being freed.  Set the magic field to bad magic
-		 * so we can detect a freed cache entry if we see
-		 * one.
+            /* Check for any flags set in the pre-serialize callback */
+            if ( serialize_flags != H5C__SERIALIZE_NO_FLAGS_SET ) 
+            {
+                /* Check for unexpected flags from serialize callback */
+                if ( serialize_flags & ~(H5C__SERIALIZE_RESIZED_FLAG | 
+                                         H5C__SERIALIZE_MOVED_FLAG |
+                                         H5C__SERIALIZE_COMPRESSED_FLAG))
+                {
+                    HGOTO_ERROR(H5E_CACHE, H5E_CANTFLUSH, FAIL, \
+                                "unknown serialize flag(s)")
+                }
+#ifdef H5_HAVE_PARALLEL
+                /* In the parallel case, resizes and moves in
+                 * the serialize operation can cause problems.
+                 * If they occur, scream and die.
+                 *
+                 * At present, in the parallel case, the aux_ptr
+                 * will only be set if there is more than one
+                 * process.  Thus we can use this to detect
+                 * the parallel case.
+                 *
+                 * This works for now, but if we start using the
+                 * aux_ptr for other purposes, we will have to
+                 * change this test accordingly.
+                 *
+                 * NB: While this test detects entryies that attempt
+                 *     to resize or move themselves during a flush
+                 *     in the parallel case, it will not detect an
+                 *     entry that dirties, resizes, and/or moves
+                 *     other entries during its flush.
+                 *
+                 *     From what Quincey tells me, this test is
+                 *     sufficient for now, as any flush routine that
+                 *     does the latter will also do the former.
+                 *
+                 *     If that ceases to be the case, further
+                 *     tests will be necessary.
+                 */
+                if ( cache_ptr->aux_ptr != NULL )
+
+                    HGOTO_ERROR(H5E_CACHE, H5E_SYSTEM, FAIL, \
+                             "resize/move in serialize occured in parallel case.")
+#endif /* H5_HAVE_PARALLEL */
+
+                /* Resize the buffer if required */
+                if ( ( ( ! entry_ptr->compressed ) &&
+                       ( serialize_flags & H5C__SERIALIZE_RESIZED_FLAG ) ) ||
+                     ( ( entry_ptr->compressed ) &&
+                       ( serialize_flags & H5C__SERIALIZE_COMPRESSED_FLAG ) ) )
+                {
+                    size_t new_image_size;
+
+            	    if ( entry_ptr->compressed )
+                        new_image_size = new_compressed_len;
+                    else
+                        new_image_size = new_len;
+
+                    HDassert(new_image_size > 0);
+
+                    /* Release the current image */
+                    if ( entry_ptr->image_ptr )
+                    {
+                        entry_ptr->image_ptr = H5MM_xfree(entry_ptr->image_ptr);
+                    }
+
+                    /* Allocate a new image buffer */
+                    entry_ptr->image_ptr = 
+                        H5MM_malloc(new_image_size + H5C_IMAGE_EXTRA_SPACE);
+
+                    if ( NULL == entry_ptr->image_ptr )
+                    {
+                        HGOTO_ERROR(H5E_CACHE, H5E_CANTALLOC, FAIL, \
+                              "memory allocation failed for on disk image buffer")
+                    }
+
+#if H5C_DO_MEMORY_SANITY_CHECKS
+
+                    HDmemcpy(((uint8_t *)entry_ptr->image_ptr) + new_image_size,
+                             H5C_IMAGE_SANITY_VALUE, 
+                             H5C_IMAGE_EXTRA_SPACE);
+
+#endif /* H5C_DO_MEMORY_SANITY_CHECKS */
+
+                } /* end if */
+
+		/* If required, update the entry and the cache data structures
+                 * for a resize.
 		 */
-		entry_ptr->magic = H5C__H5C_CACHE_ENTRY_T_BAD_MAGIC;
-#endif /* NDEBUG */
-                entry_ptr->cache_ptr = NULL;
-	    }
-            /* Call the callback routine to clear all dirty flags for object */
-            if ( (entry_ptr->type->clear)(f, entry_ptr, destroy_entry) < 0 ) {
+                if ( serialize_flags & H5C__SERIALIZE_RESIZED_FLAG ) {
+
+                    H5C__UPDATE_STATS_FOR_ENTRY_SIZE_CHANGE(cache_ptr, \
+                                                            entry_ptr, new_len)
+
+                    /* update the hash table for the size change*/
+                    H5C__UPDATE_INDEX_FOR_SIZE_CHANGE(cache_ptr, \
+                                                      entry_ptr->size, \
+                                                      new_len, entry_ptr, \
+                                                      !(entry_ptr->is_dirty));
+
+                    /* The entry can't be protected since we are
+                     * in the process of flushing it.  Thus we must
+                     * update the replacement policy data
+                     * structures for the size change.  The macro
+                     * deals with the pinned case.
+                     */
+                    H5C__UPDATE_RP_FOR_SIZE_CHANGE(cache_ptr, entry_ptr, new_len);
 
-                HGOTO_ERROR(H5E_CACHE, H5E_CANTFLUSH, FAIL, "can't clear entry")
-            }
-        } else {
+                    /* as we haven't updated the cache data structures for 
+                     * for the flush or flush destroy yet, the entry should
+                     * be in the slist.  Thus update it for the size change.
+                     */
+		    HDassert(entry_ptr->in_slist);
+                    H5C__UPDATE_SLIST_FOR_SIZE_CHANGE(cache_ptr, entry_ptr->size, \
+                                                      new_len)
+
+		    /* if defined, update *entry_size_change_ptr for the 
+                     * change in entry size.
+                     */
+                    if(entry_size_change_ptr != NULL)
+                        *entry_size_change_ptr = (int64_t)new_len - (int64_t)(entry_ptr->size);
+
+                    /* finally, update the entry for its new size */
+                    entry_ptr->size = new_len;
+                } /* end if */
 
+                /* If required, udate the entry and the cache data structures 
+                 * for a move 
+                 */
+                if(serialize_flags & H5C__SERIALIZE_MOVED_FLAG) 
+                {
 #if H5C_DO_SANITY_CHECKS
-            if ( ( entry_ptr->is_dirty ) &&
-                 ( cache_ptr->check_write_permitted == NULL ) &&
-                 ( ! (cache_ptr->write_permitted) ) )
+                    int64_t saved_slist_len_increase;
+                    int64_t saved_slist_size_increase;
+#endif /* H5C_DO_SANITY_CHECKS */
 
-                HGOTO_ERROR(H5E_CACHE, H5E_SYSTEM, FAIL, \
-                            "Write when writes are always forbidden!?!?!")
+                    H5C__UPDATE_STATS_FOR_MOVE(cache_ptr, entry_ptr)
+
+                    if ( entry_ptr->addr == old_addr )
+                    {
+                        /* we must update cache data structures for the 
+                         * change in address.
+                         */
+
+                        /* delete the entry from the hash table and the slist */
+                        H5C__DELETE_FROM_INDEX(cache_ptr, entry_ptr)
+                        H5C__REMOVE_ENTRY_FROM_SLIST(cache_ptr, entry_ptr)
+
+		        /* update the entry for its new address */
+                        entry_ptr->addr = new_addr;
+
+		        /* and then reinsert in the index and slist */
+                        H5C__INSERT_IN_INDEX(cache_ptr, entry_ptr, FAIL)
+
+#if H5C_DO_SANITY_CHECKS
+		        /* save cache_ptr->slist_len_increase and 
+                         * cache_ptr->slist_size_increase before the 
+                         * reinsertion into the slist, and restore 
+                         * them afterwards to avoid skewing our sanity
+                         * checking.
+                         */
+                        saved_slist_len_increase = cache_ptr->slist_len_increase;
+                        saved_slist_size_increase = cache_ptr->slist_size_increase;
 #endif /* H5C_DO_SANITY_CHECKS */
 
-	    if ( destroy ) {
-#ifndef NDEBUG
-	        /* we are about to call the flush callback with the
-	         * destroy flag set -- this will result in *entry_ptr
-	         * being freed.  Set the magic field to bad magic
-	         * so we can detect a freed cache entry if we see
-	         * one.
-	         */
-	        entry_ptr->magic = H5C__H5C_CACHE_ENTRY_T_BAD_MAGIC;
-#endif /* NDEBUG */
-                entry_ptr->cache_ptr = NULL;
-	    }
+                        H5C__INSERT_ENTRY_IN_SLIST(cache_ptr, entry_ptr, FAIL)
 
-            /* Only block for all the processes on the first piece of metadata
-             */
+#if H5C_DO_SANITY_CHECKS
+                        cache_ptr->slist_len_increase = saved_slist_len_increase;
+                        cache_ptr->slist_size_increase = saved_slist_size_increase;
+#endif /* H5C_DO_SANITY_CHECKS */
+                    }
+                    else /* move is alread done for us -- just do sanity checks */
+                    {
+                        HDassert(entry_ptr->addr == new_addr);
+                    }
+                } /* end if */
 
-            if ( *first_flush_ptr && entry_ptr->is_dirty ) {
+                if ( serialize_flags & H5C__SERIALIZE_COMPRESSED_FLAG ) {
+		    /* just save the new compressed entry size in 
+                     * entry_ptr->compressed_size.  We don't need to 
+ 		     * do more, as compressed size is only used for I/O.
+                     */
+                    HDassert(entry_ptr->compressed);
+                    entry_ptr->compressed_size = new_compressed_len;
+                }
+            } /* end if ( serialize_flags != H5C__SERIALIZE_NO_FLAGS_SET ) */
 
-                status = (entry_ptr->type->flush)(f, primary_dxpl_id, destroy_entry,
-                                                 entry_ptr->addr, entry_ptr,
-						 &flush_flags);
-                *first_flush_ptr = FALSE;
+            /* Serialize object into buffer */
+            {
+                size_t image_len;
 
-            } else {
+                if ( entry_ptr->compressed )
+                    image_len = entry_ptr->compressed_size;
+                else
+                    image_len = entry_ptr->size;
+
+                /* reset cache_ptr->slist_changed so we can detect slist
+                 * modifications in the serialize call.
+                 */
+                cache_ptr->slist_changed = FALSE;
+
+            
+                if ( entry_ptr->type->serialize(f, entry_ptr->image_ptr, 
+                                                image_len,
+                                                (void *)entry_ptr) < 0 )
+                {
+                    HGOTO_ERROR(H5E_CACHE, H5E_CANTFLUSH, FAIL, \
+                                "unable to serialize entry")
+                }
 
-                status = (entry_ptr->type->flush)(f, secondary_dxpl_id,
-                                                 destroy_entry, entry_ptr->addr,
-                                                 entry_ptr, &flush_flags);
+                /* set cache_ptr->slist_change_in_serialize if the 
+                 * slist was modified.
+                 */
+                if ( cache_ptr->slist_changed )
+                    cache_ptr->slist_change_in_pre_serialize = TRUE;
+
+#if H5C_DO_MEMORY_SANITY_CHECKS
+
+                HDassert(0 == HDmemcmp(((uint8_t *)entry_ptr->image_ptr) + 
+                                       image_len, 
+                                       H5C_IMAGE_SANITY_VALUE, 
+                                       H5C_IMAGE_EXTRA_SPACE));
+
+#endif /* H5C_DO_MEMORY_SANITY_CHECKS */
+
+                entry_ptr->image_up_to_date = TRUE;
             }
+        } /* end if ( ! (entry_ptr->image_up_to_date) ) */
+
+        /* Finally, write the image to disk.  
+         * 
+         * Note that if either the H5C__CLASS_NO_IO_FLAG or the 
+         * the H5AC__CLASS_SKIP_WRITES flag is set in the 
+         * in the entry's type, we silently skip the write.  This
+         * flag should only be used in test code. 
+         */
+        if ( ( ((entry_ptr->type->flags) & H5C__CLASS_NO_IO_FLAG) == 0 ) &&
+             ( ((entry_ptr->type->flags) & H5C__CLASS_SKIP_WRITES) == 0 ) )
+        {
+	    /* If compression is not enabled, the size of the entry on 
+             * disk is entry_prt->size.  However if entry_ptr->compressed
+             * is TRUE, the on disk size is entry_ptr->compressed_size.
+             */
+            size_t image_size;
 
-            if ( status < 0 ) {
+            if ( entry_ptr->compressed )
+                image_size = entry_ptr->compressed_size;
+            else
+                image_size = entry_ptr->size;
 
+            if ( ( H5F_block_write(f, entry_ptr->type->mem_type, 
+                                   entry_ptr->addr,
+                                   image_size, dxpl_id, 
+                                   entry_ptr->image_ptr) < 0 ) )
+            {
                 HGOTO_ERROR(H5E_CACHE, H5E_CANTFLUSH, FAIL, \
-                            "unable to flush entry")
+                           "Can't write image to file.")
             }
+        }
 
-#ifdef H5_HAVE_PARALLEL
-            if ( flush_flags != H5C_CALLBACK__NO_FLAGS_SET ) {
-
-                /* In the parallel case, flush operations can
-		 * cause problems.  If they occur, scream and
-		 * die.
-		 *
-		 * At present, in the parallel case, the aux_ptr
-		 * will only be set if there is more than one
-		 * process.  Thus we can use this to detect
-		 * the parallel case.
-		 *
-		 * This works for now, but if we start using the
-		 * aux_ptr for other purposes, we will have to
-		 * change this test accordingly.
-		 *
-		 * NB: While this test detects entryies that attempt
-		 *     to resize or move themselves during a flush
-		 *     in the parallel case, it will not detect an
-		 *     entry that dirties, resizes, and/or moves
-		 *     other entries during its flush.
-		 *
-		 *     From what Quincey tells me, this test is
-		 *     sufficient for now, as any flush routine that
-		 *     does the latter will also do the former.
-		 *
-		 *     If that ceases to be the case, further
-		 *     tests will be necessary.
-		 */
-		if ( cache_ptr->aux_ptr != NULL )
+        /* if the entry has a notify callback, notify it that we have 
+         * just flushed the entry.
+         */
 
-                    HGOTO_ERROR(H5E_CACHE, H5E_SYSTEM, FAIL, \
-		        "resize/move in serialize occured in parallel case.")
+        if ( ( entry_ptr->type->notify ) &&
+             ( (entry_ptr->type->notify)(H5C_NOTIFY_ACTION_AFTER_FLUSH, 
+                                         entry_ptr) < 0 ) )
+        {
+            HGOTO_ERROR(H5E_CACHE, H5E_CANTNOTIFY, FAIL, \
+                        "can't notify client of entry flush")
+        }
+    } /* if ( ( entry_ptr != NULL ) && ( write_entry ) ) */
 
-	    }
-#endif /* H5_HAVE_PARALLEL */
+
+    /* At this point, all pre-serialize and serialize calls have been
+     * made if it was appropriate to make them.  Similarly, the entry
+     * has been written to disk if desired.
+     *
+     * Thus it is now safe to update the cache data structures for the 
+     * flush.
+     */
+
+    if ( entry_ptr != NULL )
+    {
+        /* start by updating the statistics */
+
+        if ( clear_only ) {
+
+	    /* only log a clear if the entry was dirty */
+            if ( was_dirty ) {
+
+                H5C__UPDATE_STATS_FOR_CLEAR(cache_ptr, entry_ptr)
+            }
+        } else if ( write_entry ) {
+
+	    HDassert( was_dirty );
+
+	    /* only log a flush if we actually wrote to disk */
+            H5C__UPDATE_STATS_FOR_FLUSH(cache_ptr, entry_ptr)
+
+        }
+
+        if ( destroy ) 
+        {
+            if ( take_ownership )
+            {
+                HDassert(!destroy_entry);
+            }
+            else
+            {
+                HDassert(destroy_entry);
+            }
+
+	    H5C__UPDATE_STATS_FOR_EVICTION(cache_ptr, entry_ptr, \
+                                           take_ownership)
         }
 
-        if ( ( ! destroy ) && ( entry_ptr->in_slist ) ) {
+        /* If the entry's type has a 'notify' callback and the entry is about
+         * to be removed from the cache, send a 'before eviction' notice while
+         * the entry is still fully integrated in the cache.
+         */
+        if ( destroy ) {
+
+            if ( ( entry_ptr->type->notify ) &&
+                 ( (entry_ptr->type->notify)(H5C_NOTIFY_ACTION_BEFORE_EVICT, 
+                                             entry_ptr) < 0 ) )
+            {
+                HGOTO_ERROR(H5E_CACHE, H5E_CANTNOTIFY, FAIL, \
+                            "can't notify client about entry to evict")
+            }
+        } /* end if */
 
-            H5C__REMOVE_ENTRY_FROM_SLIST(cache_ptr, entry_ptr)
 
+        /* Update the cache internal data structures. */
+        if ( destroy ) 
+        {
+            /* Update the cache internal data structures as appropriate
+             * for a destroy.  Specifically:
+             *
+             * 1) Delete it from the index
+             *
+             * 2) Delete it from the skip list if requested.
+             *
+             * 3) Update the replacement policy for eviction
+             *
+             * Finally, if the destroy_entry flag is set, discard the 
+             * entry.
+             */
+
+            H5C__DELETE_FROM_INDEX(cache_ptr, entry_ptr)
+
+            if ( ( entry_ptr->in_slist ) &&
+                 ( del_entry_from_slist_on_destroy ) ) {
+
+                H5C__REMOVE_ENTRY_FROM_SLIST(cache_ptr, entry_ptr)
+            }
+
+            H5C__UPDATE_RP_FOR_EVICTION(cache_ptr, entry_ptr, FAIL)
         }
+        else
+        {
+            HDassert(clear_only || write_entry);
+            HDassert(entry_ptr->is_dirty);
+            HDassert(entry_ptr->in_slist);
+
+            /* We are either doing a flush or a clear.
+	     *
+	     * A clear and a flush are the same from the point of
+	     * view of the replacement policy and the slist.  
+             * Hence no differentiation between them.
+             *
+	     * 					JRM -- 7/7/07
+	     */
+
+            H5C__UPDATE_RP_FOR_FLUSH(cache_ptr, entry_ptr, FAIL)
 
-	if ( ( ! destroy ) && ( was_dirty ) ) {
+            H5C__REMOVE_ENTRY_FROM_SLIST(cache_ptr, entry_ptr)
+
+
+            /* mark the entry as clean and update the index for 
+             * entry clean.  Also, call the clear callback 
+             * if defined.
+             */
+
+	    entry_ptr->is_dirty = FALSE;
 
             H5C__UPDATE_INDEX_FOR_ENTRY_CLEAN(cache_ptr, entry_ptr);
+
+            if ( ( entry_ptr->type->clear != NULL ) &&
+                 ( (entry_ptr->type->clear)(f, (void *)entry_ptr, FALSE) ) )
+            {
+                HGOTO_ERROR(H5E_CACHE, H5E_CANTFLUSH, FAIL, \
+                            "unable to clear entry")
+            }
         }
 
-        if ( ! destroy ) { /* i.e. if the entry still exists */
+        /* reset the flush_in progress flag */
 
-            HDassert( !(entry_ptr->is_dirty) );
-            HDassert( !(entry_ptr->flush_marker) );
-            HDassert( !(entry_ptr->in_slist) );
-            HDassert( !(entry_ptr->is_protected) );
-            HDassert( !(entry_ptr->is_read_only) );
-            HDassert( (entry_ptr->ro_ref_count) == 0 );
+        entry_ptr->flush_in_progress = FALSE;
 
-	    if ( (flush_flags & H5C_CALLBACK__SIZE_CHANGED_FLAG) != 0 ) {
+    } /* end if */
 
-		/* The entry size changed as a result of the flush.
-		 *
-		 * Most likely, the entry was compressed, and the
-		 * new version is of a different size than the old.
-		 *
-		 * In any case, we must update entry and cache size
-		 * accordingly.
-		 */
-		size_t new_size;
 
-                if ( (entry_ptr->type->size)(f, (void *)entry_ptr, &new_size)
-                     < 0 ) {
+    /* Internal cache data structures should now be up to date, and 
+     * consistant with the status of the entry.  
+     *
+     * Now discard the entry if appropriate.
+     */
+    if ( entry_ptr != NULL )
+    {
+        if ( destroy )
+        {
+	    /* start by freeing the buffer for the on disk image */
+	    if(entry_ptr->image_ptr != NULL)
+                entry_ptr->image_ptr = H5MM_xfree(entry_ptr->image_ptr);
+
+            /* Check whether we should free the space in the file that 
+             * the entry occupies 
+             */
+            if ( free_file_space ) 
+            {
+
+		size_t fsf_size;
+
+                /* Sanity checks */
+                HDassert(H5F_addr_defined(entry_ptr->addr));
+                HDassert(!H5F_IS_TMP_ADDR(f, entry_ptr->addr));
+#ifndef NDEBUG
+{
+                hbool_t curr_compressed = FALSE;
+                size_t curr_len;
+                size_t curr_compressed_len = 0;
+
+                /* Get the actual image size for the thing again */
+                entry_ptr->type->image_len((void *)entry_ptr, &curr_len, &curr_compressed, &curr_compressed_len);
+                HDassert(curr_len == entry_ptr->size);
+		HDassert(curr_compressed == entry_ptr->compressed);
+                HDassert(curr_compressed_len == entry_ptr->compressed_size);
+}
+#endif /* NDEBUG */
 
-                    HGOTO_ERROR(H5E_RESOURCE, H5E_CANTGETSIZE, FAIL, \
-                                "Can't get entry size after flush")
+		/* if the file space free size callback is defined, use
+ 		 * it to get the size of the block of file space to free.
+ 		 * Otherwise use entry_ptr->compressed_size if 
+                 * entry_ptr->compressed == TRUE, and entry_ptr->size
+                 * if entry_ptr->compressed == FALSE.
+                 */
+		if ( entry_ptr->type->fsf_size )
+                {
+		    if ( (entry_ptr->type->fsf_size)((void *)entry_ptr, 
+                                                      &fsf_size) < 0 )
+                    {
+                        HGOTO_ERROR(H5E_CACHE, H5E_CANTFREE, FAIL, \
+                                    "unable to get file space free size")
+                    }
+                }
+                else if ( entry_ptr->compressed ) /* use compressed size */
+                {
+                    fsf_size = entry_ptr->compressed_size;
+                }
+                else /* no file space free size callback -- use entry size */
+                {
+		    fsf_size = entry_ptr->size;
                 }
 
-		if ( new_size != entry_ptr->size ) {
+                /* Release the space on disk */
+                if ( H5MF_xfree(f, entry_ptr->type->mem_type, dxpl_id, 
+                                entry_ptr->addr, (hsize_t)fsf_size) < 0)
+                {
+                    HGOTO_ERROR(H5E_CACHE, H5E_CANTFREE, FAIL, \
+                                "unable to free file space for cache entry")
+                }
+            } /* end if ( free_file_space ) */
 
-                    HDassert( entry_ptr->size < H5C_MAX_ENTRY_SIZE );
 
-                    /* update the hash table for the size change
-		     * We pass TRUE as the was_clean parameter, as we
-		     * have already updated the clean and dirty index
-		     * size fields for the fact that the entry has
-		     * been flushed. (See above call to
-		     * H5C__UPDATE_INDEX_FOR_ENTRY_CLEAN()).
-		     */
-	            H5C__UPDATE_INDEX_FOR_SIZE_CHANGE((cache_ptr), \
-				                      (entry_ptr->size), \
-                                                      (new_size), \
-						      (entry_ptr), \
-						      (TRUE))
-
-		    /* The entry can't be protected since we just flushed it.
-		     * Thus we must update the replacement policy data
-		     * structures for the size change.  The macro deals
-		     * with the pinned case.
-		     */
-		    H5C__UPDATE_RP_FOR_SIZE_CHANGE(cache_ptr, entry_ptr, \
-				                   new_size)
+	    /* Reset the pointer to the cache the entry is within. -QAK */
+            entry_ptr->cache_ptr = NULL;
 
-		    /* The entry can't be in the slist, so no need to update
-		     * the slist for the size change.
-		     */
+            /* increment entries_removed_counter and set 
+             * last_entry_removed_ptr.  As we are likely abuut to 
+             * free the entry, recall that last_entry_removed_ptr 
+             * must NEVER be dereferenced.
+             *
+	     * Recall that these fields are maintained to allow functions
+	     * that perform scans of lists of entries to detect the 
+	     * unexpected removal of entries (via expunge, eviction, 
+             * or take ownership at present), so that they can re-start
+	     * their scans if necessary.
+             */
+            cache_ptr->last_entry_removed_ptr++;
+            cache_ptr->last_entry_removed_ptr = entry_ptr;
 
-		    /* update stats for the size change */
-		    H5C__UPDATE_STATS_FOR_ENTRY_SIZE_CHANGE(cache_ptr, \
-				                            entry_ptr, \
-							    new_size)
+            /* Check for actually destroying the entry in memory */
+            /* (As opposed to taking ownership of it) */
+            if ( destroy_entry ) 
+            {
+                /* if the entry is dirty and it has a clear callback,
+                 * call this callback now.  Since this callback exists,
+                 * it follows tht the client maintains its own dirty bits, 
+                 * which must be cleared before the entry is freed to avoid 
+                 * sanity check failures.  Also clear the dirty flag for 
+                 * the same reason.
+                 */
 
-		    /* finally, update the entry size proper */
-		    entry_ptr->size = new_size;
-		}
-	    }
+                if ( entry_ptr->is_dirty ) {
 
-	    if ( (flush_flags & H5C_CALLBACK__MOVED_FLAG) != 0 ) {
-
-		/* The entry was moved as the result of the flush.
-		 *
-		 * Most likely, the entry was compressed, and the
-		 * new version is larger than the old and thus had
-		 * to be relocated.
-		 *
-		 * At preset, all processing for this case is
-		 * handled elsewhere.  But lets keep the if statement
-		 * around just in case.
-		 */
+                    entry_ptr->is_dirty = FALSE;
 
-	    }
+                    if ( ( entry_ptr->type->clear != NULL ) &&
+                         ( (entry_ptr->type->clear)(f, (void *)entry_ptr, TRUE) ) )
+                    {
+                        HGOTO_ERROR(H5E_CACHE, H5E_CANTFLUSH, FAIL, \
+                                    "unable to clear entry")
+                    }
+                }
+
+                /* we are about to discard the in core representation --
+                 * set the magic field to bad magic so we can detect a
+                 * freed entry if we see one.
+                 */
+	        entry_ptr->magic = H5C__H5C_CACHE_ENTRY_T_BAD_MAGIC;
 
-        /* reset the flush_in progress flag */
-	    entry_ptr->flush_in_progress = FALSE;
-        }
 
+                /* verify that the image has been freed */
+                HDassert( entry_ptr->image_ptr == NULL );
+
+                if ( entry_ptr->type->free_icr((void *)entry_ptr) < 0 )
+                {
+                    HGOTO_ERROR(H5E_CACHE, H5E_CANTFLUSH, FAIL, \
+                                "free_icr callback failed.")
+                }
+            } 
+            else 
+            {
+                HDassert(take_ownership);
+
+                /* client is taking ownership of the entry.
+                 * set bad magic here too so the cache will choke 
+                 * unless the entry is re-inserted properly
+                 */
+	        entry_ptr->magic = H5C__H5C_CACHE_ENTRY_T_BAD_MAGIC;
+            }
+        } /* if ( destroy ) */
+    }
+
+    if ( entry_ptr != NULL )
+    {
         if ( cache_ptr->log_flush ) {
 
             status = (cache_ptr->log_flush)(cache_ptr, addr, was_dirty, flags);
@@ -8606,8 +9611,14 @@ H5C_flush_single_entry(H5F_t *	   	   f,
     }
 
 done:
-    HDassert( ( destroy ) || 
+
+    HDassert( ( ret_value != SUCCEED ) || ( destroy_entry ) || 
               ( ( entry_ptr ) && ( ! entry_ptr->flush_in_progress ) ) );
+
+    HDassert( ( ret_value != SUCCEED ) || ( destroy_entry ) || 
+              ( take_ownership ) ||
+              ( ( entry_ptr ) && ( ! entry_ptr->is_dirty ) ) );
+
     FUNC_LEAVE_NOAPI(ret_value)
 } /* H5C_flush_single_entry() */
 
@@ -8637,8 +9648,19 @@ H5C_load_entry(H5F_t *             f,
                haddr_t             addr,
                void *              udata)
 {
+    hbool_t		dirty = FALSE;  /* Flag indicating whether thing was dirtied during deserialize */
+    hbool_t		compressed = FALSE; /* flag indicating whether thing */
+ 					/* will be run through filters on    */
+                                        /* on read and write.  Usually FALSE */
+					/* set to true if appropriate.       */
+    size_t		compressed_size = 0; /* entry compressed size if     */
+                                        /* known -- otherwise uncompressed.  */
+				        /* Zero indicates compression not    */
+                                        /* enabled.                          */
+    void *		image = NULL;   /* Buffer for disk image */
     void *		thing = NULL;   /* Pointer to thing loaded */
     H5C_cache_entry_t *	entry;          /* Alias for thing loaded, as cache entry */
+    size_t              len;            /* Size of image in file */
     unsigned            u;              /* Local index variable */
     void *		ret_value;      /* Return value */
 
@@ -8648,14 +9670,310 @@ H5C_load_entry(H5F_t *             f,
     HDassert(f->shared);
     HDassert(f->shared->cache);
     HDassert(type);
-    HDassert(type->load);
-    HDassert(type->size);
+
+    /* verify absence of prohibited or unsupported type flag combinations */
+    HDassert(!(type->flags & H5C__CLASS_NO_IO_FLAG));
+ 
+    /* for now, we do not combine the speculative load and compressed flags */
+    HDassert(!((type->flags & H5C__CLASS_SPECULATIVE_LOAD_FLAG) &&
+               (type->flags & H5C__CLASS_COMPRESSED_FLAG)));
+
+    /* Can't see how skip reads could be usefully combined with 
+     * either the speculative read or compressed flags.  Hence disallow.
+     */
+    HDassert(!((type->flags & H5C__CLASS_SKIP_READS) &&
+               (type->flags & H5C__CLASS_SPECULATIVE_LOAD_FLAG)));
+    HDassert(!((type->flags & H5C__CLASS_SKIP_READS) &&
+               (type->flags & H5C__CLASS_COMPRESSED_FLAG)));
+
     HDassert(H5F_addr_defined(addr));
+    HDassert(type->get_load_size);
+    HDassert(type->deserialize);
+
+    /* Call the get_load_size callback, to retrieve the initial 
+     * size of image 
+     */
+    if(type->get_load_size(udata, &len) < 0)
+        HGOTO_ERROR(H5E_CACHE, H5E_CANTGET, NULL, "can't retrieve image size")
+
+    HDassert(len > 0);
+
+    /* Check for possible speculative read off the end of the file */
+    if(type->flags & H5C__CLASS_SPECULATIVE_LOAD_FLAG) {
+
+/* Quincey has added patches for eoa calculations -- leave the original
+ * code around until we see the effect of these patches.
+ *                                         JRM -- 1/1/15
+ */
+#if 0 /* original code */ /* JRM */
+	/* the original version of this code has several problems:
+         *
+         * First, the sblock is not available until the sblock 
+         * has been read in, which causes a seg fault.  This is 
+         * dealt with easily enough by testing to see if 
+         * f->shared->sblock is NULL, and calling H5FD_get_base_addr()
+         * to obtain the base addr when it is.
+         *
+         * The second issue is more subtle.  H5F_get_eoa() calls 
+         * H5FD_get_eoa().  However, this function returns the EOA as 
+         * a relative address -- i.e. relative to the base address.
+         * This means that the base addr + addr < eoa sanity check will
+         * fail whenever the super block is not at address 0 when 
+         * reading in the first chunk of the super block.
+         * 
+         * To address these issues, I have rewritten the code to 
+         * simply verify that the address plus length is less than 
+         * the eoa.  I think this is sufficient, but further testing
+         * should tell me if it isn't.
+         *                                      JRM -- 8/29/14
+         */
+        haddr_t eoa;                /* End-of-allocation in the file */
+        haddr_t base_addr;          /* Base address of file data */
+
+        /* Get the file's end-of-allocation value */
+        eoa = H5F_get_eoa(f, type->mem_type);
+        HDassert(H5F_addr_defined(eoa));
+
+        /* Get the file's base address */
+	if ( f->shared->sblock ) 
+
+            base_addr = H5F_BASE_ADDR(f);
+
+	else { /* sblock not loaded yet -- use file driver info */
+
+	    HDassert(f->shared->lf);
+	    base_addr = H5FD_get_base_addr(f->shared->lf);
+
+	}
+        HDassert(H5F_addr_defined(base_addr));
+
+        /* Check for bad address in general */
+        if((addr + base_addr) > eoa)
+            HGOTO_ERROR(H5E_CACHE, H5E_BADVALUE, NULL, \
+	                "address of object past end of allocation")
+
+        /* Check if the amount of data to read will be past the eoa */
+        if((addr + base_addr + len) > eoa)
+            /* Trim down the length of the metadata */
+            len = (size_t)(eoa - (addr + base_addr));
+
+#else /* modified code */ /* JRM */
+
+        haddr_t eoa;                /* End-of-allocation in the file */
+        H5FD_mem_t  cooked_type;
+
+	/* if type == H5FD_MEM_GHEAP, H5F_block_read() forces 
+         * type to H5FD_MEM_DRAW via its call to H5F__accum_read().
+         * Thus we do the same for purposes of computing the eoa
+         * for sanity checks.
+         */
+        cooked_type = 
+           (type->mem_type == H5FD_MEM_GHEAP) ? H5FD_MEM_DRAW : type->mem_type;
+
+        /* Get the file's end-of-allocation value */
+        eoa = H5F_get_eoa(f, cooked_type);
+
+        HDassert(H5F_addr_defined(eoa));
+
+        /* Check for bad address in general */
+        if ( H5F_addr_gt(addr, eoa) )
+
+            HGOTO_ERROR(H5E_CACHE, H5E_BADVALUE, NULL, \
+	                "address of object past end of allocation")
+
+        /* Check if the amount of data to read will be past the eoa */
+        if( H5F_addr_gt((addr + len), eoa) ) {
+
+            /* Trim down the length of the metadata */
+
+            /* Note that for some cache clients, this will cause an 
+             * assertion failure.		JRM -- 8/29/14
+             */
+            len = (size_t)(eoa - addr);
+        }
+
+        if ( len <= 0 )
+            HGOTO_ERROR(H5E_CACHE, H5E_BADVALUE, NULL, \
+	                "len not positive after adjustment for EOA.")
+
+#endif /* modified code */ /* JRM */
+    }
+    /* Allocate the buffer for reading the on-disk entry image */
+    if(NULL == (image = H5MM_malloc(len + H5C_IMAGE_EXTRA_SPACE)))
+
+        HGOTO_ERROR(H5E_CACHE, H5E_CANTALLOC, NULL, \
+                    "memory allocation failed for on disk image buffer.")
+
+#if H5C_DO_MEMORY_SANITY_CHECKS
+    HDmemcpy(((uint8_t *)image) + len, H5C_IMAGE_SANITY_VALUE, H5C_IMAGE_EXTRA_SPACE);
+#endif /* H5C_DO_MEMORY_SANITY_CHECKS */
+
+    /* Get the on-disk entry image */
+    if ( 0 == (type->flags & H5C__CLASS_SKIP_READS) )
+        if(H5F_block_read(f, type->mem_type, addr, len, dxpl_id, image) < 0)
+            HGOTO_ERROR(H5E_CACHE, H5E_READERROR, NULL, "Can't read image*")
+
+    /* Deserialize the on-disk image into the native memory form */
+    if(NULL == (thing = type->deserialize(image, len, udata, &dirty)))
+        HGOTO_ERROR(H5E_CACHE, H5E_CANTLOAD, NULL, "Can't deserialize image")
+
+    /* If the client's cache has an image_len callback, check it */
+    if(type->image_len) {
+        size_t	new_len;        /* New size of on-disk image */
+
+	/* set magic and type field in *entry_ptr.  While the image_len 
+         * callback shouldn't touch the cache specific fields, it may check 
+         * these fields to ensure that it it has received the expected 
+         * value.
+         *
+         * Note that this initialization is repeated below on the off 
+         * chance that we had to re-try the deserialization.
+         */
+        entry = (H5C_cache_entry_t *)thing;
+        entry->magic = H5C__H5C_CACHE_ENTRY_T_MAGIC;
+        entry->type  = type;
+
+	/* verify that compressed and compressed_len are initialized */
+        HDassert(compressed == FALSE);
+        HDassert(compressed_size == 0);
+
+        /* Get the actual image size for the thing */
+        if(type->image_len(thing, &new_len, &compressed, &compressed_size) < 0)
+
+	    HGOTO_ERROR(H5E_CACHE, H5E_CANTGET, NULL, \
+                        "can't retrieve image length")
+
+	if(new_len == 0)
+
+	    HGOTO_ERROR(H5E_CACHE, H5E_BADVALUE, NULL, "image length is 0")
+
+        HDassert(((type->flags & H5C__CLASS_COMPRESSED_FLAG) != 0) ||
+                 ((compressed == FALSE) && (compressed_size == 0)));
+        HDassert((compressed == TRUE) || (compressed_size == 0));
+
+	if(new_len != len) {
+
+            if(type->flags & H5C__CLASS_COMPRESSED_FLAG) {
+
+                /* if new_len != len, then compression must be 
+                 * enabled on the entry.  In this case, the image_len
+                 * callback should have set compressed to TRUE, set 
+                 * new_len equal to the uncompressed size of the 
+                 * entry, and compressed_len equal to the compressed
+                 * size -- which must equal len.
+                 *
+                 * We can't verify the uncompressed size, but we can 
+		 * verify the rest with the following assertions.
+                 */
+		HDassert(compressed);
+                HDassert(compressed_size == len);
+
+		/* new_len should contain the uncompressed size.  Set len
+                 * equal to new_len, so that the cache will use the 
+                 * uncompressed size for purposes of space allocation, etc.
+                 */
+                len = new_len;
+
+            } else if (type->flags & H5C__CLASS_SPECULATIVE_LOAD_FLAG) {
+
+                void *new_image;       /* Buffer for disk image */
+
+		/* compressed must be FALSE, and compressed_size 
+                 * must be zero.
+                 */
+		HDassert(!compressed);
+		HDassert(compressed_size == 0);
+
+                /* Adjust the size of the image to match new_len */
+                if(NULL == (new_image = H5MM_realloc(image, 
+                                            new_len + H5C_IMAGE_EXTRA_SPACE)))
+
+                    HGOTO_ERROR(H5E_CACHE, H5E_CANTALLOC, NULL, \
+                               "image null after H5MM_realloc()")
+
+                image = new_image;
+
+#if H5C_DO_MEMORY_SANITY_CHECKS
+
+                HDmemcpy(((uint8_t *)image) + new_len, 
+                         H5C_IMAGE_SANITY_VALUE, H5C_IMAGE_EXTRA_SPACE);
+
+#endif /* H5C_DO_MEMORY_SANITY_CHECKS */
+
+                /* If the thing's image needs to be bigger for a speculatively
+                 *      loaded thing, free the thing and retry with new length
+                 */
+                if (new_len > len) {
+
+                    /* Release previous (possibly partially initialized) 
+                     * thing.  Note that we must set entry->magic to 
+                     * H5C__H5C_CACHE_ENTRY_T_BAD_MAGIC and set one or 
+                     * two other fields before the call to free_icr
+                     * so as to avoid sanity check failures.
+                     */
+                    entry->magic = H5C__H5C_CACHE_ENTRY_T_BAD_MAGIC;
+
+                    entry->addr  = addr;
+
+                    if ( type->free_icr(thing) < 0 )
+
+                        HGOTO_ERROR(H5E_CACHE, H5E_CANTFLUSH, NULL, \
+                                    "free_icr callback failed")
+
+                    /* Go get the on-disk image again */
+                    if(H5F_block_read(f, type->mem_type, addr, 
+                                      new_len, dxpl_id, image) < 0)
+
+                        HGOTO_ERROR(H5E_CACHE, H5E_CANTLOAD, NULL, \
+                                    "Can't read image")
+
+                    /* Deserialize on-disk image into native memory 
+                     * form again 
+                     */
+                    if(NULL == (thing = type->deserialize(image, new_len, 
+                                                          udata, &dirty)))
 
-    if(NULL == (thing = (type->load)(f, dxpl_id, addr, udata)))
+                        HGOTO_ERROR(H5E_CACHE, H5E_CANTLOAD, NULL, \
+                                    "Can't deserialize image")
 
-        HGOTO_ERROR(H5E_CACHE, H5E_CANTLOAD, NULL, "unable to load entry")
+#ifndef NDEBUG
+    		    {
+			/* new_compressed and new_compressed_size must be 
+                         * initialize to FALSE / 0 respectively, as clients
+                         * that don't use compression may ignore these two 
+                         * parameters.
+                         */
+                        hbool_t new_compressed = FALSE;
+                        size_t new_compressed_size = 0;
+                        size_t new_new_len;
+
+                        /* Get the actual image size for the thing again.  Note
+                         * that since this is a new thing, we have to set 
+                         * the magic and type fields again so as to avoid
+                         * failing sanity checks.
+                         */
+                        entry = (H5C_cache_entry_t *)thing;
+                        entry->magic = H5C__H5C_CACHE_ENTRY_T_MAGIC;
+                        entry->type  = type;
+
+                        type->image_len(thing, &new_new_len, &new_compressed, &new_compressed_size);
+                        HDassert(new_new_len == new_len);
+                        HDassert(!new_compressed);
+                        HDassert(new_compressed_size == 0);
+    		    }
+#endif /* NDEBUG */
+                } /* end if (new_len > len) */
+
+                /* Retain adjusted size */
+                len = new_len;
 
+            } else { /* throw an error */
+
+                HGOTO_ERROR(H5E_CACHE, H5E_UNSUPPORTED, NULL, \
+                     "size of non-speculative, non-compressed object changed")
+            }
+	} /* end if (new_len != len) */
+    } /* end if */
 
     entry = (H5C_cache_entry_t *)thing;
 
@@ -8663,35 +9981,39 @@ H5C_load_entry(H5F_t *             f,
      *
      * However, when this code is used in the metadata cache, it is
      * possible that object headers will be dirty at this point, as
-     * the load function will alter object headers if necessary to
+     * the deserialize function will alter object headers if necessary to
      * fix an old bug.
      *
-     * To support this bug fix, I have replace the old assert:
-     *
-     * 	HDassert( entry->is_dirty == FALSE );
-     *
-     * with:
+     * In the following assert:
      *
-     * 	HDassert( ( entry->is_dirty == FALSE ) || ( type->id == 5 ) );
+     * 	HDassert( ( dirty == FALSE ) || ( type->id == 5 || type->id == 6 ) );
      *
-     * Note that type id 5 is associated with object headers in the metadata
-     * cache.
+     * note that type ids 5 & 6 are associated with object headers in the 
+     * metadata cache.
      *
      * When we get to using H5C for other purposes, we may wish to
      * tighten up the assert so that the loophole only applies to the
      * metadata cache.
      */
 
-    HDassert( ( entry->is_dirty == FALSE ) || ( type->id == 5 ) );
-#ifndef NDEBUG
+    HDassert( ( dirty == FALSE ) || ( type->id == 5 || type->id == 6) );
+
     entry->magic                = H5C__H5C_CACHE_ENTRY_T_MAGIC;
-#endif /* NDEBUG */
     entry->cache_ptr            = f->shared->cache;
     entry->addr                 = addr;
+    entry->size                 = len;
+    HDassert(entry->size < H5C_MAX_ENTRY_SIZE);
+    entry->compressed		= compressed;
+    entry->compressed_size	= compressed_size;
+    entry->image_ptr            = image;
+    entry->image_up_to_date     = TRUE;
     entry->type                 = type;
+    entry->is_dirty	        = dirty;
+    entry->dirtied              = FALSE;
     entry->is_protected         = FALSE;
     entry->is_read_only         = FALSE;
     entry->ro_ref_count         = 0;
+    entry->is_pinned            = FALSE;
     entry->in_slist             = FALSE;
     entry->flush_marker         = FALSE;
 #ifdef H5_HAVE_PARALLEL
@@ -8700,13 +10022,6 @@ H5C_load_entry(H5F_t *             f,
 #endif /* H5_HAVE_PARALLEL */
     entry->flush_in_progress    = FALSE;
     entry->destroy_in_progress  = FALSE;
-    entry->free_file_space_on_destroy = FALSE;
-
-    if((type->size)(f, thing, &(entry->size)) < 0)
-
-        HGOTO_ERROR(H5E_RESOURCE, H5E_CANTGETSIZE, NULL, "Can't get size of thing")
-
-    HDassert( entry->size < H5C_MAX_ENTRY_SIZE );
 
     /* Initialize flush dependency height fields */
     entry->flush_dep_parent = NULL;
@@ -8727,6 +10042,18 @@ H5C_load_entry(H5F_t *             f,
     ret_value = thing;
 
 done:
+    /* Cleanup on error */
+    if(NULL == ret_value) {
+
+        /* Release resources */
+        if ( thing && type->free_icr(thing) < 0 )
+
+            HDONE_ERROR(H5E_CACHE, H5E_CANTFLUSH, NULL, \
+                        "free_icr callback failed")
+
+        if(image)
+            image = H5MM_xfree(image);
+    } /* end if */
 
     FUNC_LEAVE_NOAPI(ret_value)
 } /* H5C_load_entry() */
@@ -8765,36 +10092,45 @@ done:
  *
  * Programmer:  John Mainzer, 5/14/04
  *
- *              JRM -- 11/13/08
- *              Modified function to always observe the min_clean_size
- *              whether we are maintaining the clean and dirt LRU lists
- *              or not.  To do this, we had to add the new clean_index_size
- *              and dirty_index_size fields to H5C_t, and supporting code
- *              as needed throughout the cache.
+ * Changes:     Modified function to skip over entries with the 
+ *		flush_in_progress flag set.  If this is not done,
+ *		an infinite recursion is possible if the cache is 
+ *		full, and the pre-serialize or serialize routine 
+ *		attempts to load another entry.
  *
- *              The purpose of this modification is to avoid "metadata
- *              blizzards" in the write only case.  In such instances,
- *              the cache was allowed to fill with dirty metadata.  When
- *              we finally needed to evict an entry to make space, we had
- *              to flush out a whole cache full of metadata -- which has
- *              interesting performance effects.  We hope to avoid (or
- *              perhaps more accurately hide) this effect by maintaining
- *              the min_clean_size, which should force us to start flushing
- *              entries long before we actually have to evict something
- *              to make space.
+ *		This error was exposed by a re-factor of the 
+ *		H5C_flush_single_entry() routine.  However, it was 
+ *		a potential bug from the moment that entries were 
+ *		allowed to load other entries on flush.
+ *
+ *		In passing, note that the primary and secondary dxpls 
+ *		mentioned in the comment above have been replaced by 
+ *		a single dxpl at some point, and thus the discussion 
+ *		above is somewhat obsolete.  Date of this change is 
+ *		unkown.
+ *
+ *						JRM -- 12/26/14
+ *
+ *		Modified function to detect deletions of entries 
+ *		during a scan of the LRU, and where appropriate, 
+ *		restart the scan to avoid proceeding with a next 
+ *		entry that is no longer in the cache.
+ *
+ *		Note the absence of checks after flushes of clean 
+ *		entries.  As a second entry can only be removed by 
+ *		by a call to the pre_serialize or serialize callback
+ *		of the first, and as these callbacks will not be called
+ *		on clean entries, no checks are needed.
+ *
+ *						JRM -- 4/6/15
  *
- *              MAM -- 01/06/09
- *              Added code to maintain clean_entries_skipped and total_entries
- *              scanned statistics.
  *-------------------------------------------------------------------------
  */
 static herr_t
 H5C_make_space_in_cache(H5F_t *	f,
-                        hid_t	primary_dxpl_id,
-                        hid_t	secondary_dxpl_id,
+                        hid_t	dxpl_id,
 		        size_t	space_needed,
-                        hbool_t	write_permitted,
-                        hbool_t * first_flush_ptr)
+                        hbool_t	write_permitted)
 {
     H5C_t *		cache_ptr = f->shared->cache;
     herr_t		result;
@@ -8807,6 +10143,7 @@ H5C_make_space_in_cache(H5F_t *	f,
     size_t		empty_space;
     hbool_t		prev_is_dirty = FALSE;
     hbool_t             didnt_flush_entry = FALSE;
+    hbool_t		restart_scan;
     H5C_cache_entry_t *	entry_ptr;
     H5C_cache_entry_t *	prev_ptr;
     H5C_cache_entry_t *	next_ptr;
@@ -8817,13 +10154,12 @@ H5C_make_space_in_cache(H5F_t *	f,
     HDassert( f );
     HDassert( cache_ptr );
     HDassert( cache_ptr->magic == H5C__H5C_T_MAGIC );
-    HDassert( first_flush_ptr != NULL );
-    HDassert( ( *first_flush_ptr == TRUE ) || ( *first_flush_ptr == FALSE ) );
     HDassert( cache_ptr->index_size ==
 	      (cache_ptr->clean_index_size + cache_ptr->dirty_index_size) );
 
     if ( write_permitted ) {
 
+        restart_scan = FALSE;
         initial_list_len = cache_ptr->LRU_list_len;
         entry_ptr = cache_ptr->LRU_tail_ptr;
 
@@ -8854,6 +10190,7 @@ H5C_make_space_in_cache(H5F_t *	f,
                 ( entry_ptr != NULL )
               )
         {
+            HDassert(entry_ptr->magic == H5C__H5C_CACHE_ENTRY_T_MAGIC);
             HDassert( ! (entry_ptr->is_protected) );
             HDassert( ! (entry_ptr->is_read_only) );
             HDassert( (entry_ptr->ro_ref_count) == 0 );
@@ -8866,7 +10203,8 @@ H5C_make_space_in_cache(H5F_t *	f,
 		prev_is_dirty = prev_ptr->is_dirty;
 	    }
 
-            if ( (entry_ptr->type)->id != H5C__EPOCH_MARKER_TYPE ) {
+            if ( ( (entry_ptr->type)->id != H5C__EPOCH_MARKER_TYPE ) &&
+                 ( ! entry_ptr->flush_in_progress ) ) {
 
                 didnt_flush_entry = FALSE;
 
@@ -8881,14 +10219,29 @@ H5C_make_space_in_cache(H5F_t *	f,
                     }
 #endif /* H5C_COLLECT_CACHE_STATS */
 
+		    /* reset entries_removed_counter and 
+                     * last_entry_removed_ptr prior to the call to 
+                     * H5C_flush_single_entry() so that we can spot 
+                     * unexpected removals of entries from the cache,
+                     * and set the restart_scan flag if proceeding 
+                     * would be likely to cause us to scan an entry 
+                     * that is no longer in the cache.
+                     */
+                    cache_ptr->entries_removed_counter = 0;
+                    cache_ptr->last_entry_removed_ptr  = NULL;
+
                     result = H5C_flush_single_entry(f,
-                                                    primary_dxpl_id,
-                                                    secondary_dxpl_id,
-                                                    entry_ptr->type,
+                                                    dxpl_id,
                                                     entry_ptr->addr,
                                                     H5C__NO_FLAGS_SET,
-                                                    first_flush_ptr,
-                                                    FALSE);
+                                                    FALSE,
+                                                    NULL);
+
+		    if ( ( cache_ptr->entries_removed_counter > 1 ) ||
+                         ( cache_ptr->last_entry_removed_ptr == prev_ptr ) )
+
+                        restart_scan = TRUE;
+
                 } else if ( (cache_ptr->index_size + space_needed)
                               >
                              cache_ptr->max_cache_size ) {
@@ -8897,13 +10250,12 @@ H5C_make_space_in_cache(H5F_t *	f,
 #endif /* H5C_COLLECT_CACHE_STATS */
 
                     result = H5C_flush_single_entry(f,
-                                                    primary_dxpl_id,
-                                                    secondary_dxpl_id,
-                                                    entry_ptr->type,
+                                                    dxpl_id,
                                                     entry_ptr->addr,
                                                     H5C__FLUSH_INVALIDATE_FLAG,
-                                                    first_flush_ptr,
-                                                    TRUE);
+                                                    TRUE,
+                                                    NULL);
+
                 } else {
 
                     /* We have enough space so don't flush clean entry.
@@ -8924,7 +10276,8 @@ H5C_make_space_in_cache(H5F_t *	f,
 
             } else {
 
-                /* Skip epoch markers.  Set result to SUCCEED to avoid
+                /* Skip epoch markers and entries that are in the process
+                 * of being flushed.  Set result to SUCCEED to avoid
                  * triggering the error code below.
                  */
                 didnt_flush_entry = TRUE;
@@ -8938,26 +10291,20 @@ H5C_make_space_in_cache(H5F_t *	f,
             }
 
 	    if ( prev_ptr != NULL ) {
-#ifndef NDEBUG
-		if ( prev_ptr->magic != H5C__H5C_CACHE_ENTRY_T_MAGIC ) {
-
-		    /* something horrible has happened to *prev_ptr --
-		     * scream and die.
-		     */
-                    HGOTO_ERROR(H5E_CACHE, H5E_SYSTEM, FAIL, \
-				"*prev_ptr corrupt 1")
 
-                }
-#endif /* NDEBUG */
 		if ( didnt_flush_entry ) {
 
-		    /* epoch markers don't get flushed, so the sanity checks
-		     * on normal entries will fail -- thus just set entry_ptr
-		     * to prev_ptr and go on.
+		    /* epoch markers don't get flushed, and we don't touch 
+                     * entries that are in the process of being flushed.
+                     * Hence no need for sanity checks, as we haven't 
+                     * flushed anything.  Thus just set entry_ptr to prev_ptr 
+                     * and go on.
 		     */
                     entry_ptr = prev_ptr;
 
-		} else if ( ( prev_ptr->is_dirty != prev_is_dirty )
+		} else if ( ( restart_scan ) 
+                            ||
+                            ( prev_ptr->is_dirty != prev_is_dirty )
 		            ||
 		            ( prev_ptr->next != next_ptr )
 		            ||
@@ -8968,7 +10315,9 @@ H5C_make_space_in_cache(H5F_t *	f,
 		    /* something has happened to the LRU -- start over
 		     * from the tail.
 		     */
+                    restart_scan = FALSE;
 	            entry_ptr = cache_ptr->LRU_tail_ptr;
+		    H5C__UPDATE_STATS_FOR_LRU_SCAN_RESTART(cache_ptr)
 
 		} else {
 
@@ -9056,13 +10405,11 @@ H5C_make_space_in_cache(H5F_t *	f,
             prev_ptr = entry_ptr->aux_prev;
 
             result = H5C_flush_single_entry(f,
-                                            primary_dxpl_id,
-                                            secondary_dxpl_id,
-                                            entry_ptr->type,
+                                            dxpl_id,
                                             entry_ptr->addr,
                                             H5C__FLUSH_INVALIDATE_FLAG,
-                                            first_flush_ptr,
-                                            TRUE);
+                                            TRUE,
+                                            NULL);
 
             if ( result < 0 ) {
 
@@ -9070,6 +10417,12 @@ H5C_make_space_in_cache(H5F_t *	f,
                             "unable to flush entry")
             }
 
+	    /* we are scanning the clean LRU, so the serialize function
+	     * will not be called on any entry -- thus there is no
+	     * concern about the list being modified out from under
+	     * this function.
+	     */
+
             entry_ptr = prev_ptr;
 	    entries_examined++;
         }
@@ -9482,6 +10835,66 @@ done:
 
 /*-------------------------------------------------------------------------
  *
+ * Function:    H5C_entry_in_skip_list
+ *
+ * Purpose:     Debugging function that scans skip list to see if it 
+ *		is in present.  We need this, as it is possible for 
+ *		an entry to be in the skip list twice.
+ *
+ * Return:      FALSE if the entry is not in the skip list, and TRUE 
+ *		if it is.
+ *
+ * Programmer:  John Mainzer, 11/1/14
+ *
+ * Changes:
+ *
+ *		None.
+ *
+ *-------------------------------------------------------------------------
+ */
+#if H5C_DO_SLIST_SANITY_CHECKS
+
+static hbool_t
+H5C_entry_in_skip_list(H5C_t * cache_ptr, H5C_cache_entry_t *target_ptr)
+{
+    hbool_t in_slist              = FALSE;
+    H5SL_node_t *       node_ptr  = NULL;
+    H5C_cache_entry_t *	entry_ptr = NULL;
+
+    HDassert( cache_ptr );
+    HDassert( cache_ptr->magic == H5C__H5C_T_MAGIC );
+    HDassert( cache_ptr->slist_ptr );
+
+    node_ptr = H5SL_first(cache_ptr->slist_ptr);
+
+    while ( ( node_ptr != NULL ) && ( ! in_slist ) )
+    {
+        entry_ptr = (H5C_cache_entry_t *)H5SL_item(node_ptr);
+
+	HDassert( entry_ptr );
+	HDassert( entry_ptr->magic == H5C__H5C_CACHE_ENTRY_T_MAGIC );
+        HDassert( entry_ptr->is_dirty );
+        HDassert( entry_ptr->in_slist );
+
+        if ( entry_ptr == target_ptr ) {
+
+	    in_slist = TRUE;
+
+	} else {
+
+	    node_ptr = H5SL_next(node_ptr);
+	}
+    }
+
+    return(in_slist);
+
+} /* H5C_entry_in_skip_list() */
+
+#endif /* H5C_DO_SLIST_SANITY_CHECKS */
+
+
+/*-------------------------------------------------------------------------
+ *
  * Function:    H5C_get_entry_ptr_from_addr()
  *
  * Purpose:     Debugging function that attempts to look up an entry in the 
@@ -9784,7 +11197,7 @@ done:
  *-------------------------------------------------------------------------
  */
 static herr_t
-H5C_flush_tagged_entries(H5F_t * f, hid_t primary_dxpl_id, hid_t secondary_dxpl_id, H5C_t * cache_ptr, haddr_t tag)
+H5C_flush_tagged_entries(H5F_t * f, hid_t dxpl_id, H5C_t * cache_ptr, haddr_t tag)
 {
     herr_t      ret_value = SUCCEED;
 
@@ -9800,7 +11213,7 @@ H5C_flush_tagged_entries(H5F_t * f, hid_t primary_dxpl_id, hid_t secondary_dxpl_
         HGOTO_ERROR(H5E_CACHE, H5E_CANTFLUSH, FAIL, "Can't mark tagged entries")
 
     /* Flush all marked entries */
-    if(H5C_flush_marked_entries(f, primary_dxpl_id, secondary_dxpl_id, cache_ptr) < 0)
+    if(H5C_flush_marked_entries(f, dxpl_id, cache_ptr) < 0)
         HGOTO_ERROR(H5E_CACHE, H5E_CANTFLUSH, FAIL, "Can't flush marked entries")
 
 done:
@@ -9873,7 +11286,7 @@ H5C_mark_tagged_entries(H5C_t * cache_ptr, haddr_t tag)
  *-------------------------------------------------------------------------
  */
 static herr_t
-H5C_flush_marked_entries(H5F_t * f, hid_t primary_dxpl_id, hid_t secondary_dxpl_id, H5C_t * cache_ptr)
+H5C_flush_marked_entries(H5F_t * f, hid_t dxpl_id, H5C_t * cache_ptr)
 { 
     herr_t ret_value = SUCCEED;
 
@@ -9885,8 +11298,7 @@ H5C_flush_marked_entries(H5F_t * f, hid_t primary_dxpl_id, hid_t secondary_dxpl_
     HDassert(cache_ptr->magic == H5C__H5C_T_MAGIC);
 
     /* Flush all marked entries */
-    if(H5C_flush_cache(f, primary_dxpl_id, secondary_dxpl_id,
-            H5C__FLUSH_MARKED_ENTRIES_FLAG | H5C__FLUSH_IGNORE_PROTECTED_FLAG) < 0)
+    if(H5C_flush_cache(f, dxpl_id, H5C__FLUSH_MARKED_ENTRIES_FLAG | H5C__FLUSH_IGNORE_PROTECTED_FLAG) < 0)
         HGOTO_ERROR(H5E_CACHE, H5E_CANTFLUSH, FAIL, "Can't flush cache")
 
 done:
@@ -9929,7 +11341,7 @@ H5C_verify_tag(int id, haddr_t tag)
          * constraints are met. */
 
         /* Superblock */
-        if(id == H5AC_SUPERBLOCK_ID) {
+        if((id == H5AC_SUPERBLOCK_ID) || (id == H5AC_DRVRINFO_ID)) {
             if(tag != H5AC__SUPERBLOCK_TAG)
                 HGOTO_ERROR(H5E_CACHE, H5E_CANTTAG, FAIL, "superblock not tagged with H5AC__SUPERBLOCK_TAG")
         }
@@ -10001,10 +11413,9 @@ H5C_retag_copied_metadata(H5C_t * cache_ptr, haddr_t metadata_tag)
 
         next_entry_ptr = cache_ptr->index[u];
         while(next_entry_ptr != NULL) {
-            if(cache_ptr->index[u] != NULL) {
+            if(cache_ptr->index[u] != NULL)
                 if((cache_ptr->index[u])->tag == H5AC__COPIED_TAG)
                     (cache_ptr->index[u])->tag = metadata_tag;
-            } /* end if */
 
             next_entry_ptr = next_entry_ptr->ht_next;
         } /* end while */
diff --git a/src/H5Cpkg.h b/src/H5Cpkg.h
index 5df84cd..988dfff 100644
--- a/src/H5Cpkg.h
+++ b/src/H5Cpkg.h
@@ -60,7 +60,7 @@
 /* Cache configuration settings */
 #define H5C__HASH_TABLE_LEN     (64 * 1024) /* must be a power of 2 */
 #define H5C__H5C_T_MAGIC	0x005CAC0E
-#define H5C__MAX_NUM_TYPE_IDS	27
+#define H5C__MAX_NUM_TYPE_IDS	28
 #define H5C__PREFIX_LEN		32
 
 /****************************************************************************
@@ -573,6 +573,15 @@ if ( ( (entry_ptr) == NULL ) ||                                                \
 #define H5C__UPDATE_STATS_FOR_UNPIN(cache_ptr, entry_ptr) \
 	((cache_ptr)->unpins)[(entry_ptr)->type->id]++;
 
+#define H5C__UPDATE_STATS_FOR_SLIST_SCAN_RESTART(cache_ptr) \
+	((cache_ptr)->slist_scan_restarts)++;
+
+#define H5C__UPDATE_STATS_FOR_LRU_SCAN_RESTART(cache_ptr) \
+	((cache_ptr)->LRU_scan_restarts)++;
+
+#define H5C__UPDATE_STATS_FOR_HASH_BUCKET_SCAN_RESTART(cache_ptr) \
+	((cache_ptr)->hash_bucket_scan_restarts)++;
+
 #if H5C_COLLECT_CACHE_ENTRY_STATS
 
 #define H5C__RESET_CACHE_ENTRY_STATS(entry_ptr) \
@@ -599,9 +608,12 @@ if ( ( (entry_ptr) == NULL ) ||                                                \
     ((entry_ptr)->flushes)++;                                     \
 }
 
-#define H5C__UPDATE_STATS_FOR_EVICTION(cache_ptr, entry_ptr)             \
-{                                                                        \
-    (((cache_ptr)->evictions)[(entry_ptr)->type->id])++;                 \
+#define H5C__UPDATE_STATS_FOR_EVICTION(cache_ptr, entry_ptr, take_ownership) \
+{                                                                            \
+    if ( take_ownership )                                                    \
+        (((cache_ptr)->take_ownerships)[(entry_ptr)->type->id])++;           \
+    else                                                                     \
+        (((cache_ptr)->evictions)[(entry_ptr)->type->id])++;                 \
     if ( (entry_ptr)->accesses >                                         \
             ((cache_ptr)->max_accesses)[(entry_ptr)->type->id] )         \
         ((cache_ptr)->max_accesses)[(entry_ptr)->type->id] =             \
@@ -709,8 +721,13 @@ if ( ( (entry_ptr) == NULL ) ||                                                \
         (((cache_ptr)->pinned_flushes)[(entry_ptr)->type->id])++; \
 }
 
-#define H5C__UPDATE_STATS_FOR_EVICTION(cache_ptr, entry_ptr)      \
-    (((cache_ptr)->evictions)[(entry_ptr)->type->id])++;
+#define H5C__UPDATE_STATS_FOR_EVICTION(cache_ptr, entry_ptr, take_ownership) \
+{                                                                            \
+    if ( take_ownership )                                                    \
+        (((cache_ptr)->take_ownerships)[(entry_ptr)->type->id])++;           \
+    else                                                                     \
+        (((cache_ptr)->evictions)[(entry_ptr)->type->id])++;                 \
+}
 
 #define H5C__UPDATE_STATS_FOR_INSERTION(cache_ptr, entry_ptr)        \
 {                                                                    \
@@ -780,10 +797,13 @@ if ( ( (entry_ptr) == NULL ) ||                                                \
 #define H5C__UPDATE_STATS_FOR_INSERTION(cache_ptr, entry_ptr)
 #define H5C__UPDATE_STATS_FOR_CLEAR(cache_ptr, entry_ptr)
 #define H5C__UPDATE_STATS_FOR_FLUSH(cache_ptr, entry_ptr)
-#define H5C__UPDATE_STATS_FOR_EVICTION(cache_ptr, entry_ptr)
+#define H5C__UPDATE_STATS_FOR_EVICTION(cache_ptr, entry_ptr, take_ownership)
 #define H5C__UPDATE_STATS_FOR_PROTECT(cache_ptr, entry_ptr, hit)
 #define H5C__UPDATE_STATS_FOR_PIN(cache_ptr, entry_ptr)
 #define H5C__UPDATE_STATS_FOR_UNPIN(cache_ptr, entry_ptr)
+#define H5C__UPDATE_STATS_FOR_SLIST_SCAN_RESTART(cache_ptr)
+#define H5C__UPDATE_STATS_FOR_LRU_SCAN_RESTART(cache_ptr)
+#define H5C__UPDATE_STATS_FOR_HASH_BUCKET_SCAN_RESTART(cache_ptr)
 
 #endif /* H5C_COLLECT_CACHE_STATS */
 
@@ -828,11 +848,25 @@ if ( ( (cache_ptr) == NULL ) ||                                         \
      ( H5C__HASH_FCN((entry_ptr)->addr) >= H5C__HASH_TABLE_LEN ) ||     \
      ( (cache_ptr)->index_size !=                                       \
        ((cache_ptr)->clean_index_size +                                 \
-	(cache_ptr)->dirty_index_size) ) ) {                            \
+	(cache_ptr)->dirty_index_size) ) ||                             \
+     ( (cache_ptr)->index_size < ((cache_ptr)->clean_index_size) ) ||   \
+     ( (cache_ptr)->index_size < ((cache_ptr)->dirty_index_size) ) ) {  \
     HGOTO_ERROR(H5E_CACHE, H5E_SYSTEM, fail_val,                        \
                "Pre HT insert SC failed")                               \
 }
 
+#define H5C__POST_HT_INSERT_SC(cache_ptr, fail_val)                     \
+if ( ( (cache_ptr) == NULL ) ||                                         \
+     ( (cache_ptr)->magic != H5C__H5C_T_MAGIC ) ||                      \
+     ( (cache_ptr)->index_size !=                                       \
+       ((cache_ptr)->clean_index_size +                                 \
+	(cache_ptr)->dirty_index_size) ) ||                             \
+     ( (cache_ptr)->index_size < ((cache_ptr)->clean_index_size) ) ||   \
+     ( (cache_ptr)->index_size < ((cache_ptr)->dirty_index_size) ) ) {  \
+    HGOTO_ERROR(H5E_CACHE, H5E_SYSTEM, fail_val,                        \
+               "Post HT insert SC failed")                              \
+}
+
 #define H5C__PRE_HT_REMOVE_SC(cache_ptr, entry_ptr)                     \
 if ( ( (cache_ptr) == NULL ) ||                                         \
      ( (cache_ptr)->magic != H5C__H5C_T_MAGIC ) ||                      \
@@ -853,10 +887,28 @@ if ( ( (cache_ptr) == NULL ) ||                                         \
        ( (entry_ptr)->ht_prev != NULL ) ) ||                            \
      ( (cache_ptr)->index_size !=                                       \
        ((cache_ptr)->clean_index_size +                                 \
-	(cache_ptr)->dirty_index_size) ) ) {                            \
+	(cache_ptr)->dirty_index_size) ) ||                             \
+     ( (cache_ptr)->index_size < ((cache_ptr)->clean_index_size) ) ||   \
+     ( (cache_ptr)->index_size < ((cache_ptr)->dirty_index_size) ) ) {  \
     HGOTO_ERROR(H5E_CACHE, H5E_SYSTEM, FAIL, "Pre HT remove SC failed") \
 }
 
+#define H5C__POST_HT_REMOVE_SC(cache_ptr, entry_ptr)                     \
+if ( ( (cache_ptr) == NULL ) ||                                          \
+     ( (cache_ptr)->magic != H5C__H5C_T_MAGIC ) ||                       \
+     ( (entry_ptr) == NULL ) ||                                          \
+     ( ! H5F_addr_defined((entry_ptr)->addr) ) ||                        \
+     ( (entry_ptr)->size <= 0 ) ||                                       \
+     ( (entry_ptr)->ht_prev != NULL ) ||                                 \
+     ( (entry_ptr)->ht_prev != NULL ) ||                                 \
+     ( (cache_ptr)->index_size !=                                        \
+       ((cache_ptr)->clean_index_size +                                  \
+	(cache_ptr)->dirty_index_size) ) ||                              \
+     ( (cache_ptr)->index_size < ((cache_ptr)->clean_index_size) ) ||    \
+     ( (cache_ptr)->index_size < ((cache_ptr)->dirty_index_size) ) ) {   \
+    HGOTO_ERROR(H5E_CACHE, H5E_SYSTEM, FAIL, "Post HT remove SC failed") \
+}
+
 /* (Keep in sync w/H5C_TEST__PRE_HT_SEARCH_SC macro in test/cache_common.h -QAK) */
 #define H5C__PRE_HT_SEARCH_SC(cache_ptr, Addr, fail_val)                    \
 if ( ( (cache_ptr) == NULL ) ||                                             \
@@ -915,6 +967,8 @@ if ( ( (cache_ptr) == NULL ) ||                                         \
      ( (cache_ptr)->index_size !=                                       \
        ((cache_ptr)->clean_index_size +                                 \
         (cache_ptr)->dirty_index_size) ) ||                             \
+     ( (cache_ptr)->index_size < ((cache_ptr)->clean_index_size) ) ||   \
+     ( (cache_ptr)->index_size < ((cache_ptr)->dirty_index_size) ) ||   \
      ( ( !( was_clean ) ||                                              \
 	    ( (cache_ptr)->clean_index_size < (old_size) ) ) &&         \
 	  ( ( (was_clean) ) ||                                          \
@@ -933,6 +987,8 @@ if ( ( (cache_ptr) == NULL ) ||                                           \
      ( (cache_ptr)->index_size !=                                         \
 	  ((cache_ptr)->clean_index_size +                                \
            (cache_ptr)->dirty_index_size) ) ||                            \
+     ( (cache_ptr)->index_size < ((cache_ptr)->clean_index_size) ) ||     \
+     ( (cache_ptr)->index_size < ((cache_ptr)->dirty_index_size) ) ||     \
      ( ( !((entry_ptr)->is_dirty ) ||                                     \
 	    ( (cache_ptr)->dirty_index_size < (new_size) ) ) &&           \
 	  ( ( ((entry_ptr)->is_dirty)  ) ||                               \
@@ -953,7 +1009,9 @@ if (                                                                          \
     ( (cache_ptr)->index_size < (entry_ptr)->size ) ||                        \
     ( (cache_ptr)->dirty_index_size < (entry_ptr)->size ) ||                  \
     ( (cache_ptr)->index_size !=                                              \
-       ((cache_ptr)->clean_index_size + (cache_ptr)->dirty_index_size) ) ) {  \
+       ((cache_ptr)->clean_index_size + (cache_ptr)->dirty_index_size) ) ||   \
+    ( (cache_ptr)->index_size < ((cache_ptr)->clean_index_size) ) ||          \
+    ( (cache_ptr)->index_size < ((cache_ptr)->dirty_index_size) ) ) {         \
     HGOTO_ERROR(H5E_CACHE, H5E_SYSTEM, FAIL,                                  \
                 "Pre HT update for entry clean SC failed")                    \
 }
@@ -968,21 +1026,27 @@ if (                                                                          \
     ( (cache_ptr)->index_size < (entry_ptr)->size ) ||                        \
     ( (cache_ptr)->clean_index_size < (entry_ptr)->size ) ||                  \
     ( (cache_ptr)->index_size !=                                              \
-       ((cache_ptr)->clean_index_size + (cache_ptr)->dirty_index_size) ) ) {  \
+       ((cache_ptr)->clean_index_size + (cache_ptr)->dirty_index_size) ) ||   \
+    ( (cache_ptr)->index_size < ((cache_ptr)->clean_index_size) ) ||          \
+    ( (cache_ptr)->index_size < ((cache_ptr)->dirty_index_size) ) ) {         \
     HGOTO_ERROR(H5E_CACHE, H5E_SYSTEM, FAIL,                                  \
                 "Pre HT update for entry dirty SC failed")                    \
 }
 
 #define H5C__POST_HT_UPDATE_FOR_ENTRY_CLEAN_SC(cache_ptr, entry_ptr)        \
-if ( (cache_ptr)->index_size !=                                             \
-       ((cache_ptr)->clean_index_size + (cache_ptr)->dirty_index_size) ) {  \
+if ( ( (cache_ptr)->index_size !=                                           \
+       ((cache_ptr)->clean_index_size + (cache_ptr)->dirty_index_size) ) || \
+     ( (cache_ptr)->index_size < ((cache_ptr)->clean_index_size) ) ||       \
+     ( (cache_ptr)->index_size < ((cache_ptr)->dirty_index_size) ) ) {      \
     HGOTO_ERROR(H5E_CACHE, H5E_SYSTEM, FAIL,                                \
                 "Post HT update for entry clean SC failed")                 \
 }
 
 #define H5C__POST_HT_UPDATE_FOR_ENTRY_DIRTY_SC(cache_ptr, entry_ptr)        \
-if ( (cache_ptr)->index_size !=                                             \
-       ((cache_ptr)->clean_index_size + (cache_ptr)->dirty_index_size) ) {  \
+if ( ( (cache_ptr)->index_size !=                                           \
+       ((cache_ptr)->clean_index_size + (cache_ptr)->dirty_index_size) ) || \
+     ( (cache_ptr)->index_size < ((cache_ptr)->clean_index_size) ) ||       \
+     ( (cache_ptr)->index_size < ((cache_ptr)->dirty_index_size) ) ) {      \
     HGOTO_ERROR(H5E_CACHE, H5E_SYSTEM, FAIL,                                \
                 "Post HT update for entry dirty SC failed")                 \
 }
@@ -990,7 +1054,9 @@ if ( (cache_ptr)->index_size !=                                             \
 #else /* H5C_DO_SANITY_CHECKS */
 
 #define H5C__PRE_HT_INSERT_SC(cache_ptr, entry_ptr, fail_val)
+#define H5C__POST_HT_INSERT_SC(cache_ptr, fail_val)
 #define H5C__PRE_HT_REMOVE_SC(cache_ptr, entry_ptr)
+#define H5C__POST_HT_REMOVE_SC(cache_ptr, entry_ptr)
 #define H5C__PRE_HT_SEARCH_SC(cache_ptr, Addr, fail_val)
 #define H5C__POST_SUC_HT_SEARCH_SC(cache_ptr, entry_ptr, Addr, k, fail_val)
 #define H5C__POST_HT_SHIFT_TO_FRONT(cache_ptr, entry_ptr, k, fail_val)
@@ -1026,9 +1092,10 @@ if ( (cache_ptr)->index_size !=                                             \
 	(cache_ptr)->clean_index_size += (entry_ptr)->size;  \
     if ((entry_ptr)->flush_me_last) {                        \
         (cache_ptr)->num_last_entries++;                     \
-        HDassert((cache_ptr)->num_last_entries == 1);        \
+        HDassert((cache_ptr)->num_last_entries <= 2);        \
     }                                                        \
     H5C__UPDATE_STATS_FOR_HT_INSERTION(cache_ptr)            \
+    H5C__POST_HT_INSERT_SC(cache_ptr, fail_val)              \
 }
 
 #define H5C__DELETE_FROM_INDEX(cache_ptr, entry_ptr)          \
@@ -1052,9 +1119,10 @@ if ( (cache_ptr)->index_size !=                                             \
 	(cache_ptr)->clean_index_size -= (entry_ptr)->size;   \
     if ((entry_ptr)->flush_me_last) {                         \
         (cache_ptr)->num_last_entries--;                      \
-        HDassert((cache_ptr)->num_last_entries == 0);         \
+        HDassert((cache_ptr)->num_last_entries <= 1);         \
     }                                                         \
     H5C__UPDATE_STATS_FOR_HT_DELETION(cache_ptr)              \
+    H5C__POST_HT_REMOVE_SC(cache_ptr, entry_ptr)              \
 }
 
 #define H5C__SEARCH_INDEX(cache_ptr, Addr, entry_ptr, fail_val)             \
@@ -1205,9 +1273,20 @@ if ( (cache_ptr)->index_size !=                                             \
  *		able to dirty, resize and/or move entries during the
  *		flush.
  *
+ *		JRM -- 12/13/14
+ *		Added code to set cache_ptr->slist_changed to TRUE 
+ *		when an entry is inserted in the slist.
+ *
  *-------------------------------------------------------------------------
  */
 
+#if H5C_DO_SLIST_SANITY_CHECKS
+#define ENTRY_IN_SLIST(cache_ptr, entry_ptr) \
+    H5C_entry_in_skip_list((cache_ptr), (entry_ptr))
+#else /* H5C_DO_SLIST_SANITY_CHECKS */
+#define ENTRY_IN_SLIST(cache_ptr, entry_ptr) FALSE
+#endif /* H5C_DO_SLIST_SANITY_CHECKS */
+
 #if H5C_DO_SANITY_CHECKS
 
 #define H5C__INSERT_ENTRY_IN_SLIST(cache_ptr, entry_ptr, fail_val)             \
@@ -1218,12 +1297,14 @@ if ( (cache_ptr)->index_size !=                                             \
     HDassert( (entry_ptr)->size > 0 );                                         \
     HDassert( H5F_addr_defined((entry_ptr)->addr) );                           \
     HDassert( !((entry_ptr)->in_slist) );                                      \
+    HDassert( !ENTRY_IN_SLIST((cache_ptr), (entry_ptr)) );                     \
                                                                                \
     if(H5SL_insert((cache_ptr)->slist_ptr, entry_ptr, &(entry_ptr)->addr) < 0) \
         HGOTO_ERROR(H5E_CACHE, H5E_BADVALUE, (fail_val),                       \
                     "Can't insert entry in skip list")                         \
                                                                                \
     (entry_ptr)->in_slist = TRUE;                                              \
+    (cache_ptr)->slist_changed = TRUE;                                         \
     (cache_ptr)->slist_len++;                                                  \
     (cache_ptr)->slist_size += (entry_ptr)->size;                              \
     (cache_ptr)->slist_len_increase++;                                         \
@@ -1244,12 +1325,14 @@ if ( (cache_ptr)->index_size !=                                             \
     HDassert( (entry_ptr)->size > 0 );                                         \
     HDassert( H5F_addr_defined((entry_ptr)->addr) );                           \
     HDassert( !((entry_ptr)->in_slist) );                                      \
+    HDassert( !ENTRY_IN_SLIST((cache_ptr), (entry_ptr)) );                     \
                                                                                \
     if(H5SL_insert((cache_ptr)->slist_ptr, entry_ptr, &(entry_ptr)->addr) < 0) \
         HGOTO_ERROR(H5E_CACHE, H5E_BADVALUE, (fail_val),                       \
                     "Can't insert entry in skip list")                         \
                                                                                \
     (entry_ptr)->in_slist = TRUE;                                              \
+    (cache_ptr)->slist_changed = TRUE;                                         \
     (cache_ptr)->slist_len++;                                                  \
     (cache_ptr)->slist_size += (entry_ptr)->size;                              \
                                                                                \
@@ -1290,6 +1373,10 @@ if ( (cache_ptr)->index_size !=                                             \
  *		Updated sanity checks for the new is_read_only and
  *		ro_ref_count fields in H5C_cache_entry_t.
  *
+ *		JRM -- 12/13/14
+ *		Added code to set cache_ptr->slist_changed to TRUE 
+ *		when an entry is removed from the slist.
+ *
  *-------------------------------------------------------------------------
  */
 
@@ -1311,6 +1398,7 @@ if ( (cache_ptr)->index_size !=                                             \
                     "Can't delete entry from skip list.")           \
                                                                     \
     HDassert( (cache_ptr)->slist_len > 0 );                         \
+    (cache_ptr)->slist_changed = TRUE;                              \
     (cache_ptr)->slist_len--;                                       \
     HDassert( (cache_ptr)->slist_size >= (entry_ptr)->size );       \
     (cache_ptr)->slist_size -= (entry_ptr)->size;                   \
@@ -1341,6 +1429,11 @@ if ( (cache_ptr)->index_size !=                                             \
  *		able to dirty, resize and/or move entries during the
  *		flush.
  *
+ *		JRM -- 12/13/14
+ *		Note that we do not set cache_ptr->slist_changed to TRUE 
+ *		in this case, as the structure of the slist is not
+ *		modified.
+ *
  *-------------------------------------------------------------------------
  */
 
@@ -2706,6 +2799,10 @@ if ( (cache_ptr)->index_size !=                                             \
  *		   the max_cache_size limit until the next time the cache
  *		   attempts to load or insert an entry.
  *
+ *		d) When the evictions_enabled field is false (see below),
+ *		   the cache size will increase without limit until the
+ *		   field is set to true.
+ *
  * min_clean_size: Nominal minimum number of clean bytes in the cache.
  *              The cache attempts to maintain this number of bytes of
  *              clean data so as to avoid case b) above.  Again, this is
@@ -2756,7 +2853,7 @@ if ( (cache_ptr)->index_size !=                                             \
  *              This value should not be mistaken for footprint of the
  *              cache in memory.  The average cache entry is small, and
  *              the cache has a considerable overhead.  Multiplying the
- *              index_size by two should yield a conservative estimate
+ *              index_size by three should yield a conservative estimate
  *              of the cache's memory footprint.
  *
  * clean_index_size: Number of bytes of clean entries currently stored in
@@ -2767,12 +2864,7 @@ if ( (cache_ptr)->index_size !=                                             \
  *
  *		WARNING:
  *
- *		1) The clean_index_size field is not maintained by the
- *		   index macros, as the hash table doesn't care whether
- *		   the entry is clean or dirty.  Instead the field is
- *		   maintained in the H5C__UPDATE_RP macros.
- *
- *		2) The value of the clean_index_size must not be mistaken
+ *		   The value of the clean_index_size must not be mistaken
  *		   for the current clean size of the cache.  Rather, the
  *		   clean size of the cache is the current value of
  *		   clean_index_size plus the amount of empty space (if any)
@@ -2784,13 +2876,6 @@ if ( (cache_ptr)->index_size !=                                             \
  *		Thus we should have the invariant that clean_index_size +
  *		dirty_index_size == index_size.
  *
- *		WARNING:
- *
- *		1) The dirty_index_size field is not maintained by the
- *		   index macros, as the hash table doesn't care whether
- *		   the entry is clean or dirty.  Instead the field is
- *		   maintained in the H5C__UPDATE_RP macros.
- *
  * index:	Array of pointer to H5C_cache_entry_t of size
  *		H5C__HASH_TABLE_LEN.  At present, this value is a power
  *		of two, not the usual prime number.
@@ -2806,6 +2891,37 @@ if ( (cache_ptr)->index_size !=                                             \
  *		changing the H5C__HASH_FCN macro and the deletion of the
  *		H5C__HASH_MASK #define.  No other changes should be required.
  *
+ * With the addition of the take ownership flag, it is possible that 
+ * an entry may be removed from the cache as the result of the flush of 
+ * a second entry.  In general, this causes little trouble, but it is 
+ * possible that the entry removed may be the next entry in the scan of 
+ * a list.  In this case, we must be able to detect the fact that the 
+ * entry has been removed, so that the scan doesn't attempt to proceed with
+ * an entry that is no longer in the cache.
+ *
+ * The following fields are maintained to facilitate this.
+ *
+ * entries_removed_counter:	Counter that is incremented each time an
+ *		entry is removed from the cache by any means (eviction, 
+ *		expungement, or take ownership at this point in time).
+ *		Functions that perform scans on lists may set this field
+ *		to zero prior to calling H5C_flush_single_entry().  
+ *		Unexpected changes to the counter indicate that an entry 
+ *		was removed from the cache as a side effect of the flush.
+ *
+ * last_entry_removed_ptr:	Pointer to the instance of H5C_cache_entry_t
+ *		which contained the last entry to be removed from the cache,
+ *		or NULL if there either is no such entry, or if a function
+ *		performing a scan of a list has set this field to NULL prior
+ *		to calling H5C_flush_single_entry().
+ *
+ *		WARNING!!! This field must NEVER be dereferenced.  It is 
+ *		maintained to allow functions that perform scans of lists
+ *		to compare this pointer with their pointers to next, thus
+ *		allowing them to avoid unnecessary restarts of scans if the
+ *		pointers don't match, and if entries_removed_counter is 
+ *		one.
+ *
  *
  * With the addition of cache entry tagging, it is possible that 
  * an entry may be inserted into the cache without a tag during testing
@@ -2825,6 +2941,21 @@ if ( (cache_ptr)->index_size !=                                             \
  * are flushed. (this has been changed -- dirty entries are now removed from
  * the skip list as they are flushed.  JRM - 10/25/05)
  *
+ * slist_changed: Boolean flag used to indicate whether the contents of 
+ *		the slist has changed since the last time this flag was
+ *		reset.  This is used in the cache flush code to detect 
+ *		conditions in which pre-serialize or serialize callbacks
+ *		have modified the slist -- which obliges us to restart 
+ *		the scan of the slist from the beginning.
+ *
+ * slist_change_in_pre_serialize: Boolean flag used to indicate that 
+ *		a pre_serialize call has modified the slist since the 
+ *		last time this flag was reset.
+ *
+ * slist_change_in_serialize: Boolean flag used to indicate that 
+ *		a serialize call has modified the slist since the 
+ *		last time this flag was reset.
+ *
  * slist_len:   Number of entries currently in the skip list
  *              used to maintain a sorted list of dirty entries in the
  *              cache.
@@ -2855,6 +2986,11 @@ if ( (cache_ptr)->index_size !=                                             \
  *              explicit tests for that case should be added when said
  *              HDasserts are removed.
  *
+ *		Update: There are now two possible last entries
+ *		(superblock and file driver info message).  This
+ *		number will probably increase as we add superblock
+ *		messages.   JRM -- 11/18/14
+ *
  * With the addition of the fractal heap, the cache must now deal with
  * the case in which entries may be dirtied, moved, or have their sizes
  * changed during a flush.  To allow sanity checks in this situation, the
@@ -2863,10 +2999,11 @@ if ( (cache_ptr)->index_size !=                                             \
  *
  * slist_len_increase: Number of entries that have been added to the
  * 		slist since the last time this field was set to zero.
+ *		Note that this value can be negative.
  *
  * slist_size_increase: Total size of all entries that have been added
  * 		to the slist since the last time this field was set to
- * 		zero.
+ * 		zero.  Note that this value can be negative.
  *
  *
  * When a cache entry is protected, it must be removed from the LRU
@@ -2905,9 +3042,9 @@ if ( (cache_ptr)->index_size !=                                             \
  *         replacement policy code).
  *
  *      2) A pinned entry can be accessed or modified at any time.
- *         Therefore, the cache must check with the entry owner
- *         before flushing it.  If permission is denied, the
- *         cache just skips the entry in the flush.
+ *         This places an additional burden on the associated pre-serialize
+ *	   and serialize callbacks, which must ensure the the entry is in 
+ *	   a consistant state before creating an image of it.
  *
  *      3) A pinned entry can be marked as dirty (and possibly
  *         change size) while it is unprotected.
@@ -2965,7 +3102,8 @@ if ( (cache_ptr)->index_size !=                                             \
  * be collective and the other processes will not know to participate.
  *
  * To deal with this issue, I have modified the usual LRU policy by adding
- * clean and dirty LRU lists to the usual LRU list.
+ * clean and dirty LRU lists to the usual LRU list.  In general, these 
+ * lists are only exist in parallel builds.
  *
  * The clean LRU list is simply the regular LRU list with all dirty cache
  * entries removed.
@@ -2982,7 +3120,7 @@ if ( (cache_ptr)->index_size !=                                             \
  *
  * Even if we start with a completely clean cache, a sequence of protects
  * without unprotects can empty the clean LRU list.  In this case, the
- * cache must grow temporarily.  At the next write, we will attempt to
+ * cache must grow temporarily.  At the next sync point, we will attempt to
  * evict enough entries to reduce index_size to less than max_cache_size.
  * While this will usually be possible, all bets are off if enough entries
  * are protected.
@@ -2992,14 +3130,14 @@ if ( (cache_ptr)->index_size !=                                             \
  *
  * LRU_list_len:  Number of cache entries currently on the LRU list.
  *
- *              Observe that LRU_list_len + pl_len must always equal
- *              index_len.
+ *              Observe that LRU_list_len + pl_len + pel_len must always 
+ *		equal index_len.
  *
  * LRU_list_size:  Number of bytes of cache entries currently residing on the
  *              LRU list.
  *
- *              Observe that LRU_list_size + pl_size must always equal
- *              index_size.
+ *              Observe that LRU_list_size + pl_size + pel_size must always 
+ *		equal index_size.
  *
  * LRU_head_ptr:  Pointer to the head of the doubly linked LRU list.  Cache
  *              entries on this list are linked by their next and prev fields.
@@ -3244,6 +3382,11 @@ if ( (cache_ptr)->index_size !=                                             \
  *		equal to the array index has been evicted from the cache in
  *		the current epoch.
  *
+ * take_ownerships: Array of int64 of length H5C__MAX_NUM_TYPE_IDS + 1.  The 
+ *		cells are used to record the number of times an entry with 
+ *		type id equal to the array index has been removed from the 
+ *		cache via the H5C__TAKE_OWNERSHIP_FLAG in the current epoch.
+ *
  * moves:       Array of int64 of length H5C__MAX_NUM_TYPE_IDS + 1.  The cells
  *		are used to record the number of times an entry with type
  *		id equal to the array index has been moved in the current
@@ -3252,7 +3395,7 @@ if ( (cache_ptr)->index_size !=                                             \
  * entry_flush_moves: Array of int64 of length H5C__MAX_NUM_TYPE_IDS + 1. 
  * 		The cells are used to record the number of times an entry
  * 		with type id equal to the array index has been moved
- * 		during its flush callback in the current epoch.
+ * 		during its pre-serialize callback in the current epoch.
  *
  * cache_flush_moves: Array of int64 of length H5C__MAX_NUM_TYPE_IDS + 1. 
  * 		The cells are used to record the number of times an entry
@@ -3297,7 +3440,8 @@ if ( (cache_ptr)->index_size !=                                             \
  * entry_flush_size_changes:  Array of int64 of length
  * 		H5C__MAX_NUM_TYPE_IDS + 1.  The cells are used to record
  * 		the number of times an entry with type id equal to the
- * 		array index has changed size while in its flush callback.
+ * 		array index has changed size while in its pre-serialize 
+ *		callback.
  *
  * cache_flush_size_changes:  Array of int64 of length
  * 		H5C__MAX_NUM_TYPE_IDS + 1.  The cells are used to record
@@ -3370,7 +3514,33 @@ if ( (cache_ptr)->index_size !=                                             \
  *
  * entries_scanned_to_make_space: Number of entries scanned only when looking
  *              for entries to evict in order to make space in cache.
-
+ *
+ * 
+ * As entries are now capable of moving, loading, dirtying, and deleting 
+ * other entries in their pre_serialize and serialize callbacks, it has 
+ * been necessary to insert code to restart scans of lists so as to avoid 
+ * improper behavior if the next entry in the list is the target of one on 
+ * these operations.
+ *
+ * The following fields are use to count such occurances.  They are used 
+ * both in tests (to verify that the scan has been restarted), and to 
+ * obtain estimates of how frequently these restarts occur.
+ *
+ * slist_scan_restarts: Number of times a scan of the slist (that contains
+ *		calls to H5C_flush_single_entry()) has been restarted to 
+ *		avoid potential issues with change of status of the next 
+ *		entry in the scan.
+ *
+ * LRU_scan_restarts: Number of times a scan of the LRU list (that contains
+ *              calls to H5C_flush_single_entry()) has been restarted to 
+ *              avoid potential issues with change of status of the next 
+ *              entry in the scan.
+ *
+ * hash_bucket_scan_restarts: Number of times a scan of a hash bucket list
+ *		(that contains calls to H5C_flush_single_entry()) has been 
+ *		restarted to avoid potential issues with change of status 
+ *		of the next entry in the scan.
+ *
  * The remaining stats are collected only when both H5C_COLLECT_CACHE_STATS
  * and H5C_COLLECT_CACHE_ENTRY_STATS are true.
  *
@@ -3438,9 +3608,17 @@ struct H5C_t {
     size_t			dirty_index_size;
     H5C_cache_entry_t *		(index[H5C__HASH_TABLE_LEN]);
 
+    /* Fields to detect entries removed during scans */
+    int64_t			entries_removed_counter;
+    H5C_cache_entry_t *		last_entry_removed_ptr;
+
     /* Field to disable tag validation */
     hbool_t                     ignore_tags;
 
+    /* Fields for maintaining list of in-order entries, for flushing */
+    hbool_t			slist_changed;
+    hbool_t			slist_change_in_pre_serialize;
+    hbool_t			slist_change_in_serialize;
     int32_t                     slist_len;
     size_t                      slist_size;
     H5SL_t *                    slist_ptr;
@@ -3515,6 +3693,7 @@ struct H5C_t {
     int64_t                     clears[H5C__MAX_NUM_TYPE_IDS + 1];
     int64_t                     flushes[H5C__MAX_NUM_TYPE_IDS + 1];
     int64_t                     evictions[H5C__MAX_NUM_TYPE_IDS + 1];
+    int64_t                     take_ownerships[H5C__MAX_NUM_TYPE_IDS + 1];
     int64_t                     moves[H5C__MAX_NUM_TYPE_IDS + 1];
     int64_t                     entry_flush_moves[H5C__MAX_NUM_TYPE_IDS + 1];
     int64_t                     cache_flush_moves[H5C__MAX_NUM_TYPE_IDS + 1];
@@ -3559,6 +3738,11 @@ struct H5C_t {
     int32_t                     max_entries_skipped_in_msic;
     int32_t                     max_entries_scanned_in_msic;
     int64_t                     entries_scanned_to_make_space;
+ 
+    /* Fields for tracking skip list scan restarts */
+    int64_t			slist_scan_restarts;
+    int64_t			LRU_scan_restarts;
+    int64_t			hash_bucket_scan_restarts;
 
 #if H5C_COLLECT_CACHE_ENTRY_STATS
     int32_t                     max_accesses[H5C__MAX_NUM_TYPE_IDS + 1];
diff --git a/src/H5Cprivate.h b/src/H5Cprivate.h
index 3413381..a9ffb70 100644
--- a/src/H5Cprivate.h
+++ b/src/H5Cprivate.h
@@ -40,9 +40,30 @@
 /* Library Private Macros */
 /**************************/
 
-#define H5C_DO_SANITY_CHECKS		0
+#ifndef NDEBUG
+#define H5C_DO_SANITY_CHECKS		1
+#define H5C_DO_SLIST_SANITY_CHECKS	0
 #define H5C_DO_TAGGING_SANITY_CHECKS	1
 #define H5C_DO_EXTREME_SANITY_CHECKS	0
+#else /* NDEBUG */
+/* With rare execptions, the following defines should be set 
+ * to 0 if NDEBUG is defined 
+ */
+#define H5C_DO_SANITY_CHECKS		0
+#define H5C_DO_SLIST_SANITY_CHECKS	0
+#define H5C_DO_TAGGING_SANITY_CHECKS	0
+#define H5C_DO_EXTREME_SANITY_CHECKS	0
+#endif /* NDEBUG */
+
+/* Note: The memory sanity checks aren't going to work until I/O filters are
+ *      changed to call a particular alloc/free routine for their buffers,
+ *      because the H5AC__SERIALIZE_RESIZED_FLAG set by the fractal heap
+ *      direct block serialize callback calls H5Z_pipeline().  When the I/O
+ *      filters are changed, then we should implement "cache image alloc/free"
+ *      routines that the fractal heap direct block (and global heap) serialize
+ *      calls can use when resizing (and re-allocating) their image in the
+ *      cache. -QAK */
+#define H5C_DO_MEMORY_SANITY_CHECKS	0
 
 /* This sanity checking constant was picked out of the air.  Increase
  * or decrease it if appropriate.  Its purposes is to detect corrupt
@@ -53,9 +74,15 @@
 #define H5C_MAX_ENTRY_SIZE		((size_t)(32 * 1024 * 1024))
 
 /* H5C_COLLECT_CACHE_STATS controls overall collection of statistics
- * on cache activity.  In general, this #define should be set to 0.
+ * on cache activity.  In general, this #define should be set to 1 in
+ * debug mode, and 0 in production mode..
  */
+
+#ifndef NDEBUG
+#define H5C_COLLECT_CACHE_STATS	1
+#else /* NDEBUG */
 #define H5C_COLLECT_CACHE_STATS	0
+#endif /* NDEBUG */
 
 /* H5C_COLLECT_CACHE_ENTRY_STATS controls collection of statistics
  * in individual cache entries.
@@ -82,10 +109,20 @@
 #define H5C_MAINTAIN_CLEAN_AND_DIRTY_LRU_LISTS  0
 #endif /* H5_HAVE_PARALLEL */
 
-/* Flags returned from the 'flush' callback */
-#define H5C_CALLBACK__NO_FLAGS_SET		0x0
-#define H5C_CALLBACK__SIZE_CHANGED_FLAG		0x1
-#define H5C_CALLBACK__MOVED_FLAG		0x2
+/* Flags for cache client class behavior */
+#define H5C__CLASS_NO_FLAGS_SET			((unsigned)0x0)
+#define H5C__CLASS_SPECULATIVE_LOAD_FLAG	((unsigned)0x1)
+#define H5C__CLASS_COMPRESSED_FLAG		((unsigned)0x2)
+/* The following flags may only appear in test code */
+#define H5C__CLASS_NO_IO_FLAG			((unsigned)0x4)
+#define H5C__CLASS_SKIP_READS			((unsigned)0x8)
+#define H5C__CLASS_SKIP_WRITES			((unsigned)0x10)
+
+/* Flags for pre-serialize callback */
+#define H5C__SERIALIZE_NO_FLAGS_SET	((unsigned)0)
+#define H5C__SERIALIZE_RESIZED_FLAG	((unsigned)0x1)
+#define H5C__SERIALIZE_MOVED_FLAG	((unsigned)0x2)
+#define H5C__SERIALIZE_COMPRESSED_FLAG  ((unsigned)0x4)
 
 /* Upper and lower limits on cache size.  These limits are picked
  * out of a hat -- you should be able to change them as necessary.
@@ -112,11 +149,9 @@
  */
 #define H5C__NUM_FLUSH_DEP_HEIGHTS            6
 
-#ifndef NDEBUG
 /* Values for cache entry magic field */
 #define H5C__H5C_CACHE_ENTRY_T_MAGIC		0x005CAC0A
 #define H5C__H5C_CACHE_ENTRY_T_BAD_MAGIC	0xDeadBeef
-#endif /* NDEBUG */
 
 /* Cache configuration validation definitions */
 #define H5C_RESIZE_CFG__VALIDATE_GENERAL        0x1
@@ -169,9 +204,13 @@
  * These flags apply to H5C_insert_entry():
  * 	H5C__SET_FLUSH_MARKER_FLAG
  * 	H5C__PIN_ENTRY_FLAG
+ *	H5C__FLUSH_LAST_FLAG		; super block only
+ *	H5C__FLUSH_COLLECTIVELY_FLAG	; super block only
  *
  * These flags apply to H5C_protect()
  * 	H5C__READ_ONLY_FLAG
+ *	H5C__FLUSH_LAST_FLAG		; super block only 
+ *	H5C__FLUSH_COLLECTIVELY_FLAG	; super block only
  *
  * These flags apply to H5C_unprotect():
  * 	H5C__SET_FLUSH_MARKER_FLAG
@@ -223,63 +262,842 @@
 typedef struct H5C_t H5C_t;
 
 
-/*
- * Class methods pertaining to caching.	 Each type of cached object will
- * have a constant variable with permanent life-span that describes how
- * to cache the object.	 That variable will be of type H5C_class_t and
- * have the following required fields...
+/***************************************************************************
+ *
+ * Struct H5C_class_t
+ *
+ * Instances of H5C_class_t are used to specify the callback functions
+ * used by the metadata cache for each class of metadata cache entry.
+ * The fields of the structure are discussed below:
+ *
+ * id:	Integer field containing the unique ID of the class of metadata
+ * 	cache entries.
+ *
+ * name: Pointer to a string containing the name of the class of metadata
+ * 	cache entries.
+ *
+ * mem_type:  Instance of H5FD_mem_t, that is used to supply the
+ * 	mem type passed into H5F_block_read().
+ *
+ * flags:  Flags indicating class-specific behavior.
+ *
+ *	Whoever created the flags field neglected to document the meanings 
+ *      of the flags he created.  Hence the following discussion of the 
+ *	H5C__CLASS_SPECULATIVE_LOAD_FLAG and (to a lesser extent) 
+ *	H5C__CLASS_COMPRESSED_FLAG should be viewed with suspicion, 
+ *	as the meanings are divined from the source code, and thus may be 
+ *	inaccurate.  Please correct any errors you find.
+ *
+ *	Possible flags are:
+ *
+ *	H5C__CLASS_NO_FLAGS_SET: No special processing.
+ *
+ *	H5C__CLASS_SPECULATIVE_LOAD_FLAG: This flag appears to be used
+ *		only in H5C_load_entry().  When it is set, entries are 
+ *		permitted to change their sizes on the first attempt 
+ *		to load.  
+ *
+ *		If the new size is larger than the old, the read buffer
+ *		is reallocated to the new size, loaded from file, and the 
+ *		deserialize routine is called a second time on the 
+ *		new buffer.  The entry returned by the first call to 
+ *		the deserialize routine is discarded (via the free_icr
+ *		call) after the new size is retrieved (via the image_len
+ *		call).  Note that the new size is used as the size of the 
+ *		entry in the cache.
+ *
+ *		If the new size is smaller than the old, no new loads 
+ *		or desearializes are performed, but the new size becomes
+ *		the size of the entry in the cache.
+ *
+ *		When this flag is set, an attempt to read past the 
+ *		end of file is pemitted.  In this case, if the size 
+ *		returned get_load_size callback would result in a 
+ *		read past the end of file, the size is trunkated to 
+ *		avoid this, and processing proceeds as normal.
  *
- * LOAD:	Loads an object from disk to memory.  The function
- *		should allocate some data structure and return it.
+ *	H5C__CLASS_COMPRESSED_FLAG: This flags indicates that the entry 
+ *		may be compressed -- i.e. its on disk image is run through 
+ *		filters on the way to and from disk.  Thus the uncompressed 
+ *		(or unfiltered) size of the entry may be different from the 
+ *		size of the entry in file.  
  *
- * FLUSH:	Writes some data structure back to disk.  It would be
- *		wise for the data structure to include dirty flags to
- *		indicate whether it really needs to be written.	 This
- *		function is also responsible for freeing memory allocated
- *		by the LOAD method if the DEST argument is non-zero (by
- *              calling the DEST method).
+ *		This has the following implications:
  *
- * DEST:	Just frees memory allocated by the LOAD method.
+ *		On load, uncompressed size and load size may be different.  
+ *		Presumably, load size will be smaller than uncompressed 
+ *		size, but there is no requirement for this in the code 
+ *		(but note that I have inserted an assertion to this effect, 
+ *		which has not been triggered to date).
  *
- * CLEAR:	Just marks object as non-dirty.
+ *		On insertion, compressed (AKA filtered, AKA on disk) size 
+ *		is unknown, as the entry has yet to be run through filters.
+ *		Compressed size is computed whenever the entry is 
+ *		written (or the image is updated -- not relevant until 
+ *		journaling is brought back).
  *
- * NOTIFY:	Notify client that an action on an entry has taken/will take
- *              place
+ *		On dirty (of a clean entry), compressed (AKA filtered, 
+ *		AKA on disk) size becomes unknown.  Thus, compressed size
+ *		must be computed by the pre-serialize callback before the 
+ *		entry may be written.  
  *
- * SIZE:	Report the size (on disk) of the specified cache object.
- *		Note that the space allocated on disk may not be contiguous.
- */
+ *		Once the compressed size becomes unknown, it remains so 
+ *		until the on disk image is constructed.  
+ *
+ *		Observe that the cache needs to know the size of the entry
+ *		for space allocation purposes.  Since the compressed size 
+ *		can change or become unknown, it uses the uncompressed
+ *		size which may change, but which should always be known.  
+ *		The compressed size is used only for journaling and disk I/O.
+ *
+ *		While there is no logical reason why they could not be 
+ *		combined, due to absence of need and for simplicity of code, 
+ *		the cache does not permit both the the 
+ *		H5C__CLASS_COMPRESSED_FLAG and the 
+ *		H5C__CLASS_SPECULATIVE_LOAD_FLAG to be set in the same 
+ *		instance of H5C_class_t.
+ *
+ *      The following flags may only appear in test code.
+ *
+ *	H5C__CLASS_NO_IO_FLAG:  This flag is intended only for use in test 
+ *		code.  When it is set, any attempt to load an entry of 
+ *		the type with this flag set will trigger an assertion 
+ *		failure, and any flush of an entry with this flag set 
+ *		will not result in any write to file.
+ *
+ *	H5C__CLASS_SKIP_READS: This flags is intended only for use in test
+ *		code.  When it is set, reads on load will be skipped,
+ *		and an uninitialize buffer will be passed to the 
+ *		deserialize function.
+ *
+ *	H5C__CLASS_SKIP_WRITES: This flags is intended only for use in test
+ *		code.  When it is set, writes of buffers prepared by the 
+ *		serialize callback will be skipped.
+ *
+ * GET_LOAD_SIZE: Pointer to the 'get load size' function.
+ *
+ * 	This function must be able to determine the size of the disk image of
+ *      a metadata cache entry, given the 'udata' that will be passed to the
+ *      'deserialize' callback.
+ *
+ *	Note that if either the H5C__CLASS_SPECULATIVE_LOAD_FLAG or
+ *	the H5C__CLASS_COMPRESSED_FLAG is set, the disk image size 
+ *	returned by this callback is either a first guess (if the 
+ *	H5C__CLASS_SPECULATIVE_LOAD_FLAG is set) or (if the
+ *      H5C__CLASS_COMPRESSED_FLAG is set), the exact on disk size 
+ *	of the entry whether it has been run through filters or not.
+ *	In all other cases, the value returned should be the correct 
+ *	uncompressed size of the entry.
+ *
+ *	The typedef for the deserialize callback is as follows:
+ *
+ * 	   typedef herr_t (*H5C_get_load_size_func_t)(void *udata_ptr,
+ * 	                                           size_t *image_len_ptr);
+ *
+ *	The parameters of the deserialize callback are as follows:
+ *
+ *	udata_ptr: Pointer to user data provided in the protect call, which
+ *         	will also be passed through to the deserialize callback.
+ *
+ *	image_len_ptr: Pointer to the location in which the length in bytes 
+ *		of the in file image to be deserialized is to be returned.
+ *
+ *              This value is used by the cache to determine the size of
+ *              the disk image for the metadata, in order to read the disk
+ *              image from the file.
+ *
+ *	Processing in the get_load_size function should proceed as follows:
+ *
+ *	If successful, the function will place the length of the on disk
+ *	image associated with supplied user data in *image_len_ptr, and 
+ *	then return SUCCEED.
+ *
+ *	On failure, the function must return FAIL and push error information
+ *	onto the error stack with the error API routines, without modifying
+ *      the value pointed to by the image_len_ptr.
+ *
+ *
+ * DESERIALIZE: Pointer to the deserialize function.
+ *
+ * 	This function must be able to read a buffer containing the on disk 
+ *	image of a metadata cache entry, allocate and load the equivalent 
+ *	in core representation, and return a pointer to that representation.
+ *
+ *	The typedef for the deserialize callback is as follows:
+ *
+ * 	   typedef void *(*H5C_deserialize_func_t)(const void * image_ptr,
+ * 	                                           size_t len,
+ *                                                 void * udata_ptr,
+ *                                                 boolean * dirty_ptr);
+ *
+ *	The parameters of the deserialize callback are as follows:
+ *
+ *	image_ptr: Pointer to a buffer of length len containing the
+ *		contents of the file starting at addr and continuing
+ *		for len bytes.
+ *
+ *	len:    Length in bytes of the in file image to be deserialized.
+ *
+ *              This parameter is supplied mainly for sanity checking.
+ *              Sanity checks should be performed when compiled in debug
+ *              mode, but the parameter may be unused when compiled in
+ *              production mode.
+ *
+ *	udata_ptr: Pointer to user data provided in the protect call, which
+ *         	must be passed through to the deserialize callback.
+ *
+ *      dirty_ptr:  Pointer to boolean which the deserialize function
+ *      	must use to mark the entry dirty if it has to modify
+ *      	the entry to clean up file corruption left over from
+ *      	an old bug in the HDF5 library.
+ *
+ *	Processing in the deserialize function should proceed as follows:
+ *
+ *      If the image contains valid data, and is of the correct length,
+ *      the deserialize function must allocate space for an in core
+ *      representation of that data, load the contents of the image into
+ *      the space allocated for the in core representation, and return
+ *      a pointer to the in core representation.  Observe that an
+ *      instance of H5C_cache_entry_t must be the first item in this
+ *      representation.  The cache will initialize it after the callback
+ *      returns.
+ *
+ *      Note that the structure of the in core representation is otherwise
+ *      up to the cache client.  All that is required is that the pointer
+ *      returned be sufficient for the clients purposes when it is returned
+ *      on a protect call.
+ *
+ *      If the deserialize function has to clean up file corruption
+ *      left over from an old bug in the HDF5 library, it must set
+ *      *dirty_ptr to TRUE.  If it doesn't, no action is needed as
+ *      *dirty_ptr will be set to FALSE before the deserialize call.
+ *
+ *      If the operation fails for any reason (i.e. bad data in buffer, bad
+ *      buffer length, malloc failure, etc.) the function must return NULL and
+ *      push error information on the error stack with the error API routines.
+ *
+ *	Exceptions to the above:
+ *
+ *	If the H5C__CLASS_SPECULATIVE_LOAD_FLAG is set, the buffer supplied
+ *	to the function need not be currect on the first invocation of the 
+ *	callback in any single attempt to load the entry.
+ *
+ *	In this case, if the buffer is larger than necessary, the function
+ *	should load the entry as described above and not flag an error due
+ *	to the oversized buffer.  The cache will correct its mis-apprehension
+ *	of the entry size with a subsequent call to the image_len callback.
+ *
+ *	If the buffer is too small, and this is the first deserialize call
+ *	in the entry load operation, the function should not flag an error.
+ *	Instead, it must compute the correct size of the entry, allocate an
+ *	in core representation and initialize it to the extent that an 
+ *	immediate call to the image len callback will return the correct 
+ *	image size.
+ *
+ *	In this case, when the deserialize callback returns, the cache will
+ *	call the image length callback, realize that the supplied buffer was
+ *	too small, discard the returned in core representation, allocate
+ *	and load a new buffer of the correct size from file, and then call
+ *	the deserialize callback again.
+ *
+ *	If the H5C__CLASS_COMPRESSED_FLAG is set, exceptions are as per the
+ *	H5C__CLASS_SPECULATIVE_LOAD_FLAG, save that only oversized buffers
+ *	are permitted.
+ *
+ *
+ * IMAGE_LEN: Pointer to the image length callback.
+ *
+ *	This callback exists primarily to support 
+ *	H5C__CLASS_SPECULATIVE_LOAD_FLAG and H5C__CLASS_COMPRESSED_FLAG 
+ *	discussed above, although it is also used to obtain the size of 
+ *	newly inserted entries.
+ *
+ *	In the case of the H5C__CLASS_SPECULATIVE_LOAD_FLAG, it is used to
+ *	allow the client to change the size of an entry in the deserialize
+ *	callback.
+ *
+ *	For the H5C__CLASS_COMPRESSED_FLAG, it is used to allow the client
+ *	to indicate whether the entry is compressed (i.e. whether entries
+ *	are run through filters) and if so, to report both the uncompressed 
+ *	and the compressed entry size (i.e. the actual on disk size after
+ *	the entry has been run through filters) if that value is known.
+ *
+ *	The callback is also used in H5C_insert_entry() to obtain the 
+ *	size of the newly inserted entry.
+ *
+ *      The typedef for the image_len callback is as follows:
+ *
+ *      typedef herr_t (*H5C_image_len_func_t)(void *thing,
+ *                                           size_t *image_len_ptr,
+ *                                           hbool_t *compressed_ptr,
+ *                                           size_t *compressed_image_len_ptr);
+ *
+ * 	The parameters of the image_len callback are as follows:
+ *
+ *	thing:  Pointer to the in core representation of the entry.
+ *
+ *	image_len_ptr: Pointer to size_t in which the callback will return
+ *		the length (in bytes) of the cache entry.
+ *
+ *		If the H5C__CLASS_COMPRESSED_FLAG is not set in the 
+ *		associated instance of H5C_class_t, or if the flag is 
+ *		set, and the callback sets *compressed_ptr to FALSE,
+ *		this size is the actual size of the entry on disk.
+ *
+ *		Otherwise, this size is the uncompressed size of the 
+ *		entry -- which the cache will use for all purposes OTHER
+ *		than journal writes and disk I/O.
+ *
+ *	compressed_ptr: Pointer to a boolean flag indicating whether 
+ *		the cache entry will be compressed / uncompressed on 
+ *		disk writes / reads.
+ *
+ *		If the H5C__CLASS_COMPRESSED_FLAG is not set in the
+ *              associated instance of H5C_class_t, *compressed_ptr 
+ *		must be set to FALSE.
+ *
+ *		If the H5C__CLASS_COMPRESSED_FLAG is set in the
+ *              associated instance of H5C_class_t, and filters are 
+ *		not enabled, *compressed_ptr must be set to FALSE.
+ *
+ *		If the H5C__CLASS_COMPRESSED_FLAG is set in the
+ *              associated instance of H5C_class_t, and filters are
+ *		enabled, the callback must set *compressed_ptr to TRUE.
+ *
+ *		Note that *compressed_ptr will always be set to FALSE 
+ *		by the caller prior to invocation of the callback.  Thus 
+ *		callbacks for clients that don't set the 
+ *		H5C__CLASS_COMPRESSED_FLAG can ignore this parameter.
+ *
+ *	compressed_image_len_ptr: Pointer to size_t in which the callback 
+ *		may return the length (in bytes) of the compressed on 
+ *		disk image of the entry, or the uncompressed size if the
+ *		compressed size has not yet been calculated.
+ *
+ *		Since computing the compressed image len is expensive, 
+ *		the callback should only report the most recently computed
+ *		value -- which will typically be incorrect if the entry
+ *		is dirty.
+ *
+ *		If *compressed_ptr is set to FALSE, *compressed_image_len_ptr
+ *		should be set to zero.  However, as *compressed_image_len_ptr
+ *		will be initialize to zero prior to the call, the callback 
+ *		need not modify it if the H5C__CLASS_COMPRESSED_FLAG is 
+ *		not set.
+ *
+ *	If the H5C__CLASS_COMPRESSED_FLAG is not set in the associated 
+ *	instance of H5C_class_t, processing in the image_len function 
+ *	should proceed as follows:
+ *
+ *	If successful, the function will place the length of the on disk
+ *	image associated with the in core representation provided in the
+ *	thing parameter in *image_len_ptr, and then return SUCCEED.  Since
+ *	*compressed_ptr and *compressed_image_len_ptr will be initialized to 
+ *	FALSE and zero respectively before the call, the callback need not
+ *	modify these values, and may declare the associated parameters as 
+ *	UNUSED.
+ *
+ *	If the H5C__CLASS_COMPRESSED_FLAG is set in the associated 
+ *      instance of H5C_class_t, processing in the image_len function 
+ *      should proceed as follows:
+ *
+ *	If successful, the function will place the uncompressed length of 
+ *	the on disk image associated with the in core representation 
+ *	provided in the thing parameter in *image_len_ptr.  If filters 
+ *	are not enabled for the entry, it will set *compressed_ptr to FALSE,
+ *      and *compressed_image_len_ptr to zero.  If filters are enabled, 
+ *	it will set *compressed_ptr to TRUE.  In this case, it must set 
+ *	*compressed_image_len_ptr equal to the last computed compressed
+ *	if the compressed size, or to the uncompressed size if that value
+ *	is yet to be computed.  In all cases, it will return SUCCEED if 
+ *	successful.
+ *
+ *	In either case, if the function fails, it must return FAIL and 
+ *	push error information onto the error stack with the error API 
+ *	routines, and return without modifying the values pointed to by 
+ *	the image_len_ptr, compressed_ptr, and compressed_image_len_ptr
+ *	parameters.
+ *
+ * PRE_SERIALIZE: Pointer to the pre-serialize callback.
+ *
+ *	The pre-serialize callback is invoked by the metadata cache before
+ *	it needs a current on-disk image of the metadata entry for purposes
+ *	either constructing a journal or flushing the entry to disk.
+ *
+ *      If the client needs to change the address or compressed or 
+ *	uncompressed length of the entry prior to flush, the pre-serialize 
+ *	callback is responsible for these actions, so that the actual 
+ *	serialize callback (described below) is only responsible for 
+ *	serializing the data structure, not moving it on disk or resizing it.
+ *
+ *	In addition, the client may use the pre-serialize callback to 
+ *	ensure that the entry is ready to be flushed -- in particular, 
+ *	if the entry contains references to other entries that are in 
+ *	temporary file space, the pre-serialize callback must move those
+ *	entries into real file space so that the serialzed entry will 
+ *	contain no invalid data.
+ *
+ *	One would think that the base address and length of
+ *	the length of the entry's image on disk would be well known. 
+ *	However, that need not be the case as free space section info
+ *	entries will change size (and possibly location) depending on the 
+ *	number of blocks of free space being manages, and fractal heap 
+ *	direct blocks can change compressed size (and  possibly location) 
+ *	on serialization if compression is enabled.  Similarly, it may
+ *	be necessary to move entries from temporary to real file space.
+ *
+ *	The pre-serialize callback must report any such changes to the 
+ *	cache, which must then update its internal structures as needed.
+ *
+ *	The typedef for the pre-serialize callback is as follows:
+ *
+ *	typedef herr_t (*H5C_pre_serialize_func_t)(const H5F_t *f,
+ *                                             hid_t dxpl_id,
+ *                                             void * thing,
+ *                                             haddr_t addr,
+ *                                             size_t len,
+ *					       size_t compressed_len,
+ *                                             haddr_t * new_addr_ptr,
+ *                                             size_t * new_len_ptr,
+ *					       size_t * new_compressed_len_ptr,
+ *                                             unsigned * flags_ptr);
+ *
+ *	The parameters of the pre-serialize callback are as follows:
+ *
+ *	f:	File pointer -- needed if other metadata cache entries
+ *		must be modified in the process of serializing the
+ *		target entry.
+ *
+ *	dxpl_id: dxpl_id passed with the file pointer to the cache, and
+ *	        passed on to the callback.  Necessary as some callbacks
+ *	        revise the size and location of the target entry, or
+ *	        possibly other entries on pre-serialize.
+ *
+ *	thing:  Pointer to void containing the address of the in core
+ *		representation of the target metadata cache entry. 
+ *		This is the same pointer returned by a protect of the
+ *		addr and len given above.
+ *
+ *	addr:   Base address in file of the entry to be serialized.
+ *
+ *		This parameter is supplied mainly for sanity checking.
+ *		Sanity checks should be performed when compiled in debug
+ *		mode, but the parameter may be unused when compiled in
+ *		production mode.
+ *
+ *	len:    Length in bytes of the in file image of the entry to be
+ *		serialized.  Also the size the image passed to the 
+ *		serialize callback (discussed below) unless either that 
+ *		value is altered by this function, or the entry will be
+ *		compressed.  In the latter case, the compressed size
+ *		of the entry will be reported in *new_compressed_len_ptr.
+ *
+ *		This parameter is supplied mainly for sanity checking.
+ *		Sanity checks should be performed when compiled in debug
+ *		mode, but the parameter may be unused when compiled in
+ *		production mode.
+ *
+ *	compressed_len: If the entry is to be compressed (i.e. run through 
+ *		filters) prior to flush, Length in bytes of the last know 
+ *		compressed size of the entry -- or the uncompressed size 
+ *		if no such value exists (i.e. the entry has been inserted, 
+ *		but never flushed).  This parameter should be set to zero
+ *		in all other cases.
+ *
+ *		This parameter is supplied mainly for sanity checking.
+ *		Sanity checks should be performed when compiled in debug
+ *		mode, but the parameter may be unused when compiled in
+ *		production mode.
+ *
+ *	new_addr_ptr:  Pointer to haddr_t.  If the entry is moved by
+ *		the serialize function, the new on disk base address must
+ *		be stored in *new_addr_ptr, and the appropriate flag set
+ *		in *flags_ptr.  
+ *
+ *		If the entry is not moved by the serialize function, 
+ *		*new_addr_ptr is undefined on pre-serialize callback 
+ *		return.
+ *
+ *	new_len_ptr:  Pointer to size_t.  If the entry is resized by the
+ *		serialize function, the new length of the on disk image
+ *		must be stored in *new_len_ptr, and the appropriate flag set
+ *              in *flags_ptr.
+ *
+ *		If the entry is not resized by the pre-serialize function, 
+ *		*new_len_ptr is undefined on pre-serialize callback 
+ *		return.
+ *
+ *	new_compressed_len_ptr: Pointer to size_t.  If the image will be
+ *		compressed (i.e. run through filters) prior to being 
+ *		written to disk, the compressed size (in bytes) of the
+ *		on disk image must be stored in *new_compressed_len_ptr,
+ *		and the appropriate flag set in *flags_ptr.  
+ *
+ *	flags_ptr:  Pointer to an unsigned integer used to return flags
+ *		indicating whether the preserialize function resized or moved
+ *		the entry, or computed its compressed size.  If the entry was 
+ *		neither resized or moved, nor will be compressed,
+ *		the serialize function must set *flags_ptr to zero. 
+ *		H5C__SERIALIZE_RESIZED_FLAG, H5C__SERIALIZE_MOVED_FLAG
+ *		and H5C__SERIALIZE_COMPRESSED_FLAG must be set to indicate 
+ *		a resize, a move, or compression respectively.
+ *
+ *	        If the H5C__SERIALIZE_RESIZED_FLAG is set, the new length
+ *	        must be stored in *new_len_ptr.
+ *
+ *	        If the H5C__SERIALIZE_MOVED_FLAG flag is set, the
+ *	        new image base address must be stored in *new_addr_ptr. 
+ *
+ *		If the H5C__SERIALIZE_COMPRESSED_FLAG is set, the 
+ *		compressed size of the new image must be stored in 
+ *		*new_compressed_len_ptr. 
+ *
+ *	Processing in the pre-serialize function should proceed as follows:
+ *
+ *	The pre-serialize function must examine the in core representation
+ *	indicated by the thing parameter, if the pre-serialize function does
+ *      not need to change the size or location of the on-disk image, or
+ *	compute its compress size, it must set *flags_ptr to zero. 
+ *
+ *	If the (uncompressed) size of the on-disk image must be changed, 
+ *	the pre-serialize function must load the length of the new image 
+ *	into *new_len_ptr, and set the H5C__SERIALIZE_RESIZED_FLAG in 
+ *	*flags_ptr. 
+ *
+ *	If the base address of the on disk image must be changed, the
+ *      pre-serialize function must set *new_addr_ptr to the new base address,
+ *      and set the H5C__SERIALIZE_MOVED_FLAG in *flags_ptr.
+ *
+ *	If the H5C__CLASS_COMPRESSED_FLAG is set in the assocated instance
+ *	of H5C_class_t, and filters (i.e. compression) are enabled, the 
+ *	pre-serialize function must compute the compressed size of the 
+ *	on disk image, and if it has changed, load this value into 
+ *	*new_compressed_len_ptr, and set H5C__SERIALIZE_COMPRESSED_FLAG in 
+ *	*flags_ptr.
+ *
+ *	Note that to do this, the preserialize function will typically have 
+ *	to serialize the entry, and run it through the filters to obtain 
+ *	the compressed size.  For efficiency, the compressed image may
+ *	be stored to be copied into the supplied buffer by the 
+ *	serialize callback.  Needless to say this is awkward.  We may
+ *	want to re-work the API for cache clients to simplify this.
+ *
+ *	In addition, the pre-serialize callback may perform any other 
+ *	processing required before the entry is written to disk
+ *
+ *	If it is successful, the function must return SUCCEED. 
+ *
+ *	If it fails for any reason, the function must return FAIL and
+ *	push error information on the error stack with the error API
+ *	routines.
+ *
+ *
+ * SERIALIZE: Pointer to the serialize callback.
+ *
+ *	The serialize callback is invoked by the metadata cache whenever
+ *	it needs a current on disk image of the metadata entry for purposes
+ *	either constructing a journal entry or flushing the entry to disk.
+ *
+ *	At this point, the base address and length of the entry's image on
+ *      disk must be well known and not change during the serialization
+ *      process. 
+ *
+ *	While any size and/or location changes must have been handled 
+ *	by a pre-serialize call, the client may elect to handle any other 
+ *	changes to the entry required to place it in correct form for 
+ *	writing to disk in this call.
+ *
+ *	The typedef for the serialize callback is as follows:
+ *
+ *	typedef herr_t (*H5C_serialize_func_t)(const H5F_t *f,
+ *                                             void * image_ptr,
+ *                                             size_t len,
+ *                                             void * thing);
+ *
+ *	The parameters of the serialize callback are as follows:
+ *
+ *	f:	File pointer -- needed if other metadata cache entries
+ *		must be modified in the process of serializing the
+ *		target entry.
+ *
+ *	image_ptr: Pointer to a buffer of length len bytes into which a
+ *		serialized image of the target metadata cache entry is
+ *		to be written.
+ *
+ * 		Note that this buffer will not in general be initialized
+ * 		to any particular value.  Thus the serialize function may
+ * 		not assume any initial value and must set each byte in
+ * 		the buffer.
+ *
+ *	len:    Length in bytes of the in file image of the entry to be
+ *		serialized.  Also the size of *image_ptr (below).  If 
+ *		compression is not enabled, this value is simply the 
+ *		uncompressed size of the entry's image on disk.  If 
+ *		compression is enabled, this value is the size of the 
+ *		compressed image.
+ *
+ *		This parameter is supplied mainly for sanity checking.
+ *		Sanity checks should be performed when compiled in debug
+ *		mode, but the parameter may be unused when compiled in
+ *		production mode.
+ *
+ *	thing:  Pointer to void containing the address of the in core
+ *		representation of the target metadata cache entry. 
+ *		This is the same pointer returned by a protect of the
+ *		addr and len given above.
+ *
+ *	Processing in the serialize function should proceed as follows:
+ *
+ *	If there are any remaining changes to the entry required before 
+ *	write to disk, they must be dealt with first.
+ *
+ *	The serialize function must then examine the in core 
+ *	representation indicated by the thing parameter, and write a 
+ *	serialized (and possibly compressed) image of its contents into 
+ *	the provided buffer. 
+ *
+ *	If it is successful, the function must return SUCCEED. 
+ *
+ *	If it fails for any reason, the function must return FAIL and
+ *	push error information on the error stack with the error API
+ *	routines.
+ *
+ *
+ * NOTIFY: Pointer to the notify callback.
+ *
+ *      The notify callback is invoked by the metadata cache when a cache
+ *      action on an entry has taken/will take place and the client indicates
+ *      it wishes to be notified about the action.
+ *
+ *	The typedef for the notify callback is as follows:
+ *
+ *	typedef herr_t (*H5C_notify_func_t)(H5C_notify_action_t action,
+ *                                          void *thing);
+ *
+ * 	The parameters of the notify callback are as follows:
+ *
+ *	action: An enum indicating the metadata cache action that has taken/
+ *              will take place.
+ *
+ *	thing:  Pointer to void containing the address of the in core
+ *		representation of the target metadata cache entry.  This
+ *		is the same pointer that would be returned by a protect
+ *		of the addr and len of the entry. 
+ *
+ *	Processing in the notify function should proceed as follows:
+ *
+ *	The notify function may perform any action it would like, including
+ *      metadata cache calls.
+ *
+ *	If the function is successful, it must return SUCCEED. 
+ *
+ *	If it fails for any reason, the function must return FAIL and
+ *	push error information on the error stack with the error API
+ *	routines. 
+ *
+ *
+ * FREE_ICR: Pointer to the free ICR callback.
+ *
+ *	The free ICR callback is invoked by the metadata cache when it
+ *	wishes to evict an entry, and needs the client to free the memory
+ *	allocated for the in core representation. 
+ *
+ *	The typedef for the free ICR callback is as follows:
+ *
+ *	typedef herr_t (*H5C_free_icr_func_t)(void * thing));
+ *
+ * 	The parameters of the free ICR callback are as follows:
+ *
+ *	thing:  Pointer to void containing the address of the in core
+ *		representation of the target metadata cache entry.  This
+ *		is the same pointer that would be returned by a protect
+ *		of the addr and len of the entry. 
+ *
+ *	Processing in the free ICR function should proceed as follows:
+ *
+ *	The free ICR function must free all memory allocated to the
+ *	in core representation. 
+ *
+ *	If the function is successful, it must return SUCCEED. 
+ *
+ *	If it fails for any reason, the function must return FAIL and
+ *	push error information on the error stack with the error API
+ *	routines. 
+ *
+ *	At least when compiled with debug, it would be useful if the
+ *	free ICR call would fail if the in core representation has been
+ *	modified since the last serialize of clear callback.
+ *
+ * CLEAR: Pointer to the clear callback.
+ *
+ *	In principle, there should be no need for the clear callback,
+ *	as the dirty flag should be maintained by the metadata cache.
+ *.  
+ *	However, some clients maintain dirty bits on internal data, 
+ *	and we need some way of keeping these dirty bits in sync with 
+ *	those maintained by the metadata cache.  This callback exists
+ *	to serve this purpose.  If defined, it is called whenever the 
+ *	cache marks dirty entry clean, or when the cache is about to 
+ *	discard a dirty entry without writing it to disk (This 
+ *	happens as the result of an unprotect call with the 
+ *	H5AC__DELETED_FLAG set, and the H5C__TAKE_OWNERSHIP_FLAG not
+ *	set.)
+ *
+ *	Arguably, this functionality should be in the NOTIFY callback.
+ *	However, this callback is specific to only a few clients, and 
+ *	it will be called relatively frequently.  Hence it is made its
+ *	own callback to minimize overhead.
+ *
+ *	The typedef for the clear callback is as follows:
+ *
+ *	typedef herr_t (*H5C_clear_func_t)(const H5F_t *f,
+ *                                         void * thing, 
+ *                                         hbool_t about_to_destroy);
+ *
+ *	The parameters of the clear callback are as follows:
+ *
+ *	f:	File pointer.
+ *
+ *	thing:  Pointer to void containing the address of the in core
+ *		representation of the target metadata cache entry.  This
+ *		is the same pointer that would be returned by a protect()
+ *		call of the associated addr and len.
+ *
+ *	about_to_destroy: Boolean flag used to indicate whether the 
+ *		metadata cache is about to destroy the target metadata
+ *		cache entry.  The callback may use this flag to omit
+ *		operations that are irrelevant it the entry is about 
+ *		to be destroyed.
+ *
+ *	Processing in the clear function should proceed as follows:
+ *
+ *	Reset all internal dirty bits in the target metadata cache entry.
+ *
+ *	If the about_to_destroy flag is TRUE, the clear function may 
+ *	ommit any dirty bit that will not trigger a sanity check failure 
+ *	or otherwise cause problems in the subsequent free icr call.
+ *	In particular, the call must ensure that the free icr call will
+ *	not fail due to changes prior to this call, and after the 
+ *	last serialize or clear call.
+ *
+ *	If the function is successful, it must return SUCCEED. 
+ *
+ *	If it fails for any reason, the function must return FAIL and
+ *	push error information on the error stack with the error API
+ *	routines. 
+ *
+ * GET_FSF_SIZE: Pointer to the get file space free size callback.
+ *
+ *	In principle, there is no need for the get file space free size
+ *	callback.  However, as an optimization, it is sometimes convenient
+ *	to allocate and free file space for a number of cache entries 
+ *	simultaneously in a single contiguous block of file space.
+ *
+ *	File space allocation is done by the client, so the metadata cache
+ *	need not be involved.  However, since the metadata cache typically
+ *      handles file space release when an entry is destroyed, some 
+ *	adjustment on the part of the metadata cache is required for this
+ *	operation.
+ *
+ *      The get file space free size callback exists to support this 
+ *	operation.
+ *
+ *	If a group of cache entries that were allocated as a group are to 
+ *	be discarded and their file space released, the type of the first
+ *	(i.e. lowest address) entry in the group must implement the 
+ *	get free file space size callback.  
+ *
+ *	To free the file space of all entries in the group in a single 
+ *	operation, first expunge all entries other than the first without 
+ *	the free file space flag.  
+ *
+ *	Then, to complete the operation, unprotect or expunge the first
+ *	entry in the block with the free file space flag set.  Since 
+ *	the get free file space callback is implemented, the metadata 
+ *	cache will use this callback to get the size of the block to be
+ *	freed, instead of using the size of the entry as is done otherwise.
+ *
+ *	At present this callback is used only by the H5FA and H5EA dblock
+ *	and dblock page client classes.
+ *
+ *      The typedef for the clear callback is as follows:
+ *
+ *      typedef herr_t (*H5C_get_fsf_size_t)(const void * thing,
+ *                                                size_t *fsf_size_ptr);
+ *
+ *      The parameters of the clear callback are as follows:
+ *
+ *      thing:  Pointer to void containing the address of the in core
+ *              representation of the target metadata cache entry.  This
+ *              is the same pointer that would be returned by a protect()
+ *              call of the associated addr and len.
+ *
+ *	fs_size_ptr: Pointer to size_t in which the callback will return
+ *              the size of the piece of file space to be freed.  Note 
+ *		that the space to be freed is presumed to have the same 
+ *		base address as the cache entry.
+ *
+ *      The function simply returns the size of the block of file space
+ *	to be freed in *fsf_size_ptr.  
+ *
+ *	If the function is successful, it must return SUCCEED.
+ *
+ *      If it fails for any reason, the function must return FAIL and
+ *      push error information on the error stack with the error API
+ *      routines.
+ *
+ ***************************************************************************/
 
 /* Actions that can be reported to 'notify' client callback */
 typedef enum H5C_notify_action_t {
-    H5C_NOTIFY_ACTION_AFTER_INSERT,     /* Entry has been added to the cache */
-                                        /* (could be loaded from file with
-                                         *      'protect' call, or inserted
-                                         *      with 'set' call)
+    H5C_NOTIFY_ACTION_AFTER_INSERT,     /* Entry has been added to the cache 
+                                         * via the insert call
+                                         */
+    H5C_NOTIFY_ACTION_AFTER_LOAD,	/* Entry has been loaded into the 
+                                         * from file via the protect call
+                                         */
+    H5C_NOTIFY_ACTION_AFTER_FLUSH,	/* Entry has just been flushed to
+ 					 * file.
+                                         */
+    H5C_NOTIFY_ACTION_BEFORE_EVICT      /* Entry is about to be evicted 
+                                         * from cache.
                                          */
-    H5C_NOTIFY_ACTION_BEFORE_EVICT      /* Entry is about to be evicted from cache */
 } H5C_notify_action_t;
 
 /* Cache client callback function pointers */
-typedef void *(*H5C_load_func_t)(H5F_t *f, hid_t dxpl_id, haddr_t addr,
-    void *udata);
-typedef herr_t (*H5C_flush_func_t)(H5F_t *f, hid_t dxpl_id, hbool_t dest,
-    haddr_t addr, void *thing, unsigned *flags_ptr);
-typedef herr_t (*H5C_dest_func_t)(H5F_t *f, void *thing);
-typedef herr_t (*H5C_clear_func_t)(H5F_t *f, void *thing, hbool_t dest);
+typedef herr_t (*H5C_get_load_size_func_t)(const void *udata_ptr,
+    size_t *image_len_ptr);
+typedef void *(*H5C_deserialize_func_t)(const void *image_ptr,
+    size_t len, void *udata_ptr, hbool_t *dirty_ptr);
+typedef herr_t (*H5C_image_len_func_t)(const void *thing,
+    size_t *image_len_ptr, hbool_t *compressed_ptr, size_t *compressed_image_len_ptr);
+typedef herr_t (*H5C_pre_serialize_func_t)(const H5F_t *f, hid_t dxpl_id,
+    void *thing, haddr_t addr, size_t len, size_t compressed_len,
+    haddr_t *new_addr_ptr, size_t *new_len_ptr, size_t *new_compressed_len_ptr,
+    unsigned *flags_ptr);
+typedef herr_t (*H5C_serialize_func_t)(const H5F_t *f, void *image_ptr,
+    size_t len, void *thing);
 typedef herr_t (*H5C_notify_func_t)(H5C_notify_action_t action, void *thing);
-typedef herr_t (*H5C_size_func_t)(const H5F_t *f, const void *thing,
-    size_t *size_ptr);
+typedef herr_t (*H5C_free_icr_func_t)(void *thing);
+typedef herr_t (*H5C_clear_func_t)(const H5F_t *f, void * thing, 
+    hbool_t about_to_destroy);
+typedef herr_t (*H5C_get_fsf_size_t)(const void * thing, size_t *fsf_size_ptr);
 
 /* Metadata cache client class definition */
 typedef struct H5C_class_t {
-    int			id;
-    H5C_load_func_t	load;
-    H5C_flush_func_t	flush;
-    H5C_dest_func_t	dest;
-    H5C_clear_func_t	clear;
-    H5C_notify_func_t	notify;
-    H5C_size_func_t	size;
+    int				id;
+    const char *		name;
+    H5FD_mem_t			mem_type;
+    unsigned			flags;
+    H5C_get_load_size_func_t 	get_load_size;
+    H5C_deserialize_func_t 	deserialize;
+    H5C_image_len_func_t	image_len;
+    H5C_pre_serialize_func_t	pre_serialize;
+    H5C_serialize_func_t	serialize;
+    H5C_notify_func_t		notify;
+    H5C_free_icr_func_t	        free_icr;
+    H5C_clear_func_t		clear;
+    H5C_get_fsf_size_t		fsf_size;
 } H5C_class_t;
 
 /* Type defintions of callback functions used by the cache as a whole */
@@ -312,7 +1130,7 @@ typedef herr_t (*H5C_log_flush_func_t)(H5C_t *cache_ptr, haddr_t addr,
  *              just before the entry is freed.
  *
  *              This is necessary, as the LRU list can be changed out
- *              from under H5C_make_space_in_cache() by the flush
+ *              from under H5C_make_space_in_cache() by the serialize
  *              callback which may change the size of an existing entry,
  *              and/or load a new entry while serializing the target entry.
  *
@@ -325,18 +1143,66 @@ typedef herr_t (*H5C_log_flush_func_t)(H5C_t *cache_ptr, haddr_t addr,
  *              detect this case, and re-start its scan from the bottom
  *              of the LRU when this situation occurs.
  *
- *              This field is only compiled in debug mode.
+ * cache_ptr:	Pointer to the cache that this entry is contained within.
  *
  * addr:	Base address of the cache entry on disk.
  *
- * size:	Length of the cache entry on disk.  Note that unlike normal
- *		caches, the entries in this cache are of variable length.
- *		The entries should never overlap, and when we do writebacks,
- *		we will want to writeback adjacent entries where possible.
+ * size:	Length of the cache entry on disk in bytes(exception: if 
+ *		the entry is compressed on disk, this field contains the 
+ *		uncompressed size of the entry -- see discussion of 
+ *		compressed entries below).  Note that unlike normal 
+ *		caches, the entries in this cache are of arbitrary size.
+ *
+ *		With the exception of compressed entries, the file space
+ *		allocations for cache entries implied by the addr and size
+ *		fields must be disjoint.  For compressed entries,
+ *		the size field contains the uncompressed size -- thus in
+ *		in this case, substitution of compressed size for size 
+ *		must result in disjoint file space allocations.  However, 
+ *		as discussed below, the compressed size may not be know.
+ *
+ *		Any entry whose associated instance of H5C_class_t has the
+ *		H5C__CLASS_COMPRESSED_FLAG set may be compressed.  When
+ *		an entry is compressed (that is, when filters are enabled
+ *		on it), the compressed flag (see below) must be set, and 
+ *		the compressed size (if known), must be stored in 
+ *		the compressed_size field.
+ *
+ *		Since the compressed size will be unknown unless the 
+ *		entry is clean, or has an up to date image (see the 
+ *		image_ptr and image_up_to_date fields below), we use the 
+ *		uncompressed size for all purposes other than disk I/O.  
+ *		
+ * compressed:	Boolean flag that is set iff the instance of H5C_class_t
+ *		associated with the entry has the H5C__CLASS_COMPRESSED_FLAG
+ *		set, and filters are enabled on the entry.
+ *
+ * compressed_size: If compressed is TRUE, this field contains the actual
+ *		compressed size of the entry in bytes, which is also its 
+ *		true size on disk -- or the uncompressed size if the 
+ *		compressed size is unknown (i.e. the entry has been 
+ *		inserted in the cache, but it has not been compressed yet).
+ *              Note that this value will usually be incorrect if the 
+ *		entry is dirty.
+ *
+ *		Since this value is frequently out of date and expensive to 
+ *		compute, it is used only for disk I/O.  The uncompressed 
+ *		size of the entry (stored in the size field above) is used 
+ *		for all other purposes (i.e. computing the sum of the sizes 
+ *		of all entries in the cache, etc.).
+ *
+ *		If compressed is FALSE, this field should contain 0.
+ *
+ * image_ptr:	Pointer to void.  When not NULL, this field points to a
+ * 		dynamically allocated block of size bytes in which the
+ * 		on disk image of the metadata cache entry is stored.
+ *
+ * 		If the entry is dirty, the pre-serialize and serialize 
+ *		callbacks must be used to update this image before it is 
+ *		written to disk
  *
- *		NB: At present, entries need not be contiguous on disk.  Until
- *		    we fix this, we can't do much with writing back adjacent
- *		    entries.
+ * image_up_to_date:  Boolean flag that is set to TRUE when *image_ptr
+ * 		is up to date, and set to false when the entry is dirtied.
  *
  * type:	Pointer to the instance of H5C_class_t containing pointers
  *		to the methods for cache entries of the current type.  This
@@ -366,6 +1232,9 @@ typedef herr_t (*H5C_log_flush_func_t)(H5C_t *cache_ptr, haddr_t addr,
  *		      modules using the cache.  These still clear the
  *		      is_dirty field as before.  -- JRM 7/5/05
  *
+ *		Update: Management of the is_dirty field is now entirely
+ *		      in the cache.		 -- JRM 7/5/07
+ *
  * dirtied:	Boolean flag used to indicate that the entry has been
  * 		dirtied while protected.
  *
@@ -422,9 +1291,10 @@ typedef herr_t (*H5C_log_flush_func_t)(H5C_t *cache_ptr, haddr_t addr,
  * 		   policy code (LRU at present).
  *
  * 		2) A pinned entry can be accessed or modified at any time.
- * 		   Therefore, the cache must check with the entry owner
- * 		   before flushing it.  If permission is denied, the
- * 		   cache does not flush the entry.
+ * 		   This places an extra burden on the pre-serialize and 
+ *		   serialize callbacks, which must ensure that a pinned 
+ *		   entry is consistant and ready to write to disk before 
+ *		   generating an image.
  *
  * 		3) A pinned entry can be marked as dirty (and possibly
  *		   change size) while it is unprotected.
@@ -466,6 +1336,11 @@ typedef herr_t (*H5C_log_flush_func_t)(H5C_t *cache_ptr, haddr_t addr,
  *              will need to be expanded and tested appropriately if that
  *              functionality is desired.
  *
+ *		Update: There are now two possible last entries
+ *                   	(superblock and file driver info message).  This
+ *                   	number will probably increase as we add superblock
+ *                   	messages.   JRM -- 11/18/14
+ *
  * clear_on_unprotect:  Boolean flag used only in PHDF5.  When H5C is used
  *		to implement the metadata cache In the parallel case, only
  *		the cache with mpi rank 0 is allowed to actually write to
@@ -493,11 +1368,6 @@ typedef herr_t (*H5C_log_flush_func_t)(H5C_t *cache_ptr, haddr_t addr,
  * destroy_in_progress:  Boolean flag that is set to true iff the entry
  * 		is in the process of being flushed and destroyed.
  *
- * free_file_space_on_destroy:  Boolean flag that is set to true iff the entry
- * 		is in the process of being flushed and destroyed and the file
- *              space used by the object should be freed by the cache client's
- *              'dest' callback routine.
- *
  *
  * Fields supporting the 'flush dependency' feature:
  *
@@ -581,63 +1451,43 @@ typedef herr_t (*H5C_log_flush_func_t)(H5C_t *cache_ptr, haddr_t addr,
  * The use of the replacement policy fields under the Modified LRU policy
  * is discussed below:
  *
- * next:	Next pointer in either the LRU or the protected list,
- *		depending on the current value of protected.  If there
- *		is no next entry on the list, this field should be set
- *		to NULL.
+ * next:	Next pointer in either the LRU, the protected list, or 
+ *		the pinned list depending on the current values of 
+ *		is_protected and is_pinned.  If there is no next entry 
+ *		on the list, this field should be set to NULL.
  *
- * prev:	Prev pointer in either the LRU or the protected list,
- *		depending on the current value of protected.  If there
- *		is no previous entry on the list, this field should be
- *		set to NULL.
+ * prev:	Prev pointer in either the LRU, the protected list,
+ *		or the pinned list depending on the current values of 
+ *		is_protected and is_pinned.  If there is no previous 
+ *		entry on the list, this field should be set to NULL.
  *
  * aux_next:	Next pointer on either the clean or dirty LRU lists.
- *		This entry should be NULL when protected is true.  When
- *		protected is false, and dirty is true, it should point
- *		to the next item on the dirty LRU list.  When protected
- *		is false, and dirty is false, it should point to the
- *		next item on the clean LRU list.  In either case, when
- *		there is no next item, it should be NULL.
+ *		This entry should be NULL when either is_protected or 
+ *		is_pinned is true.  
+ *
+ *		When is_protected and is_pinned are false, and is_dirty is 
+ *		true, it should point to the next item on the dirty LRU 
+ *		list.  
+ *
+ *		When is_protected and is_pinned are false, and is_dirty is 
+ *		false, it should point to the next item on the clean LRU 
+ *		list.  In either case, when there is no next item, it 
+ *		should be NULL.
  *
  * aux_prev:	Previous pointer on either the clean or dirty LRU lists.
- *		This entry should be NULL when protected is true.  When
- *		protected is false, and dirty is true, it should point
- *		to the previous item on the dirty LRU list.  When protected
- *		is false, and dirty is false, it should point to the
- *		previous item on the clean LRU list.  In either case, when
- *		there is no previous item, it should be NULL.
- *
- *
- * Fields supporting metadata journaling:
- *
- * last_trans:	unit64_t containing the ID of the last transaction in
- * 		which this entry was dirtied.  If journaling is disabled,
- * 		or if the entry has never been dirtied in a transaction,
- * 		this field should be set to zero.  Once we notice that
- * 		the specified transaction has made it to disk, we will
- * 		reset this field to zero as well.
- *
- * 		We must maintain this field, as to avoid messages from
- * 		the future, we must not flush a dirty entry to disk
- * 		until the last transaction in which it was dirtied
- * 		has made it to disk in the journal file.
- *
- * trans_next:  Next pointer in the entries modified in the current
- * 		transaction list.  This field should always be null
- * 		unless journaling is enabled, the entry is dirty,
- * 		and last_trans field contains the current transaction
- * 		number.  Even if all these conditions are fulfilled,
- * 		the field will still be NULL if this is the last
- * 		entry on the list.
- *
- * trans_prev:  Previous pointer in the entries modified in the current
- * 		transaction list.  This field should always be null
- * 		unless journaling is enabled, the entry is dirty,
- * 		and last_trans field contains the current transaction
- * 		number.  Even if all these conditions are fulfilled,
- * 		the field will still be NULL if this is the first
- * 		entry on the list.
+ *		This entry should be NULL when either is_protected or 
+ *		is_pinned is true.  
+ *
+ *		When is_protected and is_pinned are false, and is_dirty is 
+ *		true, it should point to the previous item on the dirty 
+ *		LRU list.  
+ *	
+ *		When is_protected and is_pinned are false, and is_dirty 
+ *		is false, it should point to the previous item on the 
+ *		clean LRU list.  
  *
+ *		In either case, when there is no previous item, it should 
+ *		be NULL.
  *
  * Cache entry stats collection fields:
  *
@@ -659,12 +1509,14 @@ typedef herr_t (*H5C_log_flush_func_t)(H5C_t *cache_ptr, haddr_t addr,
  *
  ****************************************************************************/
 typedef struct H5C_cache_entry_t {
-#ifndef NDEBUG
     uint32_t			magic;
-#endif /* NDEBUG */
     H5C_t                     * cache_ptr;
     haddr_t			addr;
     size_t			size;
+    hbool_t			compressed;
+    size_t			compressed_size;
+    void  		      *	image_ptr;
+    hbool_t			image_up_to_date;
     const H5C_class_t	      *	type;
     haddr_t		        tag;
     hbool_t			is_dirty;
@@ -683,7 +1535,6 @@ typedef struct H5C_cache_entry_t {
 #endif /* H5_HAVE_PARALLEL */
     hbool_t			flush_in_progress;
     hbool_t			destroy_in_progress;
-    hbool_t		        free_file_space_on_destroy;
 
     /* fields supporting the 'flush dependency' feature: */
     struct H5C_cache_entry_t  *	flush_dep_parent;
@@ -1012,12 +1863,11 @@ H5_DLL void H5C_def_auto_resize_rpt_fcn(H5C_t *cache_ptr, int32_t version,
     double hit_rate, enum H5C_resize_status status,
     size_t old_max_cache_size, size_t new_max_cache_size,
     size_t old_min_clean_size, size_t new_min_clean_size);
-H5_DLL herr_t H5C_dest(H5F_t *f, hid_t primary_dxpl_id, hid_t secondary_dxpl_id);
-H5_DLL herr_t H5C_expunge_entry(H5F_t *f, hid_t primary_dxpl_id, hid_t secondary_dxpl_id,
+H5_DLL herr_t H5C_dest(H5F_t *f, hid_t dxpl_id);
+H5_DLL herr_t H5C_expunge_entry(H5F_t *f, hid_t dxpl_id,
     const H5C_class_t *type, haddr_t addr, unsigned flags);
-H5_DLL herr_t H5C_flush_cache(H5F_t *f, hid_t primary_dxpl_id, hid_t secondary_dxpl_id,
-    unsigned flags);
-H5_DLL herr_t H5C_flush_to_min_clean(H5F_t *f, hid_t primary_dxpl_id, hid_t secondary_dxpl_id);
+H5_DLL herr_t H5C_flush_cache(H5F_t *f, hid_t dxpl_id, unsigned flags);
+H5_DLL herr_t H5C_flush_to_min_clean(H5F_t *f, hid_t dxpl_id);
 H5_DLL herr_t H5C_get_cache_auto_resize_config(const H5C_t *cache_ptr,
     H5C_auto_size_ctl_t *config_ptr);
 H5_DLL herr_t H5C_get_cache_size(H5C_t *cache_ptr, size_t *max_size_ptr,
@@ -1031,17 +1881,17 @@ H5_DLL herr_t H5C_get_entry_status(const H5F_t *f, haddr_t addr,
 H5_DLL herr_t H5C_get_evictions_enabled(const H5C_t *cache_ptr, hbool_t *evictions_enabled_ptr);
 H5_DLL FILE *H5C_get_trace_file_ptr(const H5C_t *cache_ptr);
 H5_DLL FILE *H5C_get_trace_file_ptr_from_entry(const H5C_cache_entry_t *entry_ptr);
-H5_DLL herr_t H5C_insert_entry(H5F_t *f, hid_t primary_dxpl_id, hid_t secondary_dxpl_id,
-    const H5C_class_t *type, haddr_t addr, void *thing, unsigned int flags);
-H5_DLL herr_t H5C_mark_entries_as_clean(H5F_t *f, hid_t primary_dxpl_id,
-    hid_t secondary_dxpl_id, int32_t ce_array_len, haddr_t *ce_array_ptr);
+H5_DLL herr_t H5C_insert_entry(H5F_t *f, hid_t dxpl_id, const H5C_class_t *type,
+    haddr_t addr, void *thing, unsigned int flags);
+H5_DLL herr_t H5C_mark_entries_as_clean(H5F_t *f, hid_t dxpl_id, int32_t ce_array_len,
+    haddr_t *ce_array_ptr);
 H5_DLL herr_t H5C_mark_entry_dirty(void *thing);
 H5_DLL herr_t H5C_move_entry(H5C_t *cache_ptr, const H5C_class_t *type,
     haddr_t old_addr, haddr_t new_addr);
 H5_DLL herr_t H5C_pin_protected_entry(void *thing);
 H5_DLL herr_t H5C_create_flush_dependency(void *parent_thing, void *child_thing);
-H5_DLL void * H5C_protect(H5F_t *f, hid_t primary_dxpl_id, hid_t secondary_dxpl_id,
-    const H5C_class_t *type, haddr_t addr, void *udata, unsigned flags);
+H5_DLL void * H5C_protect(H5F_t *f, hid_t dxpl_id, const H5C_class_t *type,
+    haddr_t addr, void *udata, unsigned flags);
 H5_DLL herr_t H5C_reset_cache_hit_rate_stats(H5C_t *cache_ptr);
 H5_DLL herr_t H5C_resize_entry(void *thing, size_t new_size);
 H5_DLL herr_t H5C_set_cache_auto_resize_config(H5C_t *cache_ptr,
@@ -1055,17 +1905,17 @@ H5_DLL void H5C_stats__reset(H5C_t *cache_ptr);
 H5_DLL herr_t H5C_dump_cache(H5C_t *cache_ptr, const char *cache_name);
 H5_DLL herr_t H5C_unpin_entry(void *thing);
 H5_DLL herr_t H5C_destroy_flush_dependency(void *parent_thing, void *child_thing);
-H5_DLL herr_t H5C_unprotect(H5F_t *f, hid_t primary_dxpl_id, hid_t secondary_dxpl_id,
-    const H5C_class_t *type, haddr_t addr, void *thing, unsigned int flags);
+H5_DLL herr_t H5C_unprotect(H5F_t *f, hid_t dxpl_id, const H5C_class_t *type,
+    haddr_t addr, void *thing, unsigned int flags);
 H5_DLL herr_t H5C_validate_resize_config(H5C_auto_size_ctl_t *config_ptr,
     unsigned int tests);
 H5_DLL herr_t H5C_ignore_tags(H5C_t *cache_ptr);
 H5_DLL void H5C_retag_copied_metadata(H5C_t *cache_ptr, haddr_t metadata_tag);
 
 #ifdef H5_HAVE_PARALLEL
-H5_DLL herr_t H5C_apply_candidate_list(H5F_t *f, hid_t primary_dxpl_id,
-    hid_t secondary_dxpl_id, H5C_t *cache_ptr, int num_candidates,
-    haddr_t *candidates_list_ptr, int mpi_rank, int mpi_size);
+H5_DLL herr_t H5C_apply_candidate_list(H5F_t *f, hid_t dxpl_id,
+    H5C_t *cache_ptr, int num_candidates, haddr_t *candidates_list_ptr,
+    int mpi_rank, int mpi_size);
 H5_DLL herr_t H5C_construct_candidate_list__clean_cache(H5C_t *cache_ptr);
 H5_DLL herr_t H5C_construct_candidate_list__min_clean(H5C_t *cache_ptr);
 #endif /* H5_HAVE_PARALLEL */
diff --git a/src/H5Dlayout.c b/src/H5Dlayout.c
index d7d7b88..01898f2 100644
--- a/src/H5Dlayout.c
+++ b/src/H5Dlayout.c
@@ -253,7 +253,7 @@ H5D__layout_oh_create(H5F_t *file, hid_t dxpl_id, H5O_t *oh, H5D_t *dset,
             HGOTO_ERROR(H5E_DATASET, H5E_CANTINIT, FAIL, "unable to create EFL file name heap")
 
         /* Pin the heap down in memory */
-        if(NULL == (heap = H5HL_protect(file, dxpl_id, efl->heap_addr, H5AC_WRITE)))
+        if(NULL == (heap = H5HL_protect(file, dxpl_id, efl->heap_addr, H5AC__NO_FLAGS_SET)))
             HGOTO_ERROR(H5E_DATASET, H5E_CANTPROTECT, FAIL, "unable to protect EFL file name heap")
 
         /* Insert "empty" name first */
diff --git a/src/H5EA.c b/src/H5EA.c
index 37682e7..d96f9c2 100644
--- a/src/H5EA.c
+++ b/src/H5EA.c
@@ -148,7 +148,7 @@ HDfprintf(stderr, "%s: Called\n", FUNC);
 	H5E_THROW(H5E_CANTALLOC, "memory allocation failed for extensible array info")
 
     /* Lock the array header into memory */
-    if(NULL == (hdr = H5EA__hdr_protect(f, dxpl_id, ea_addr, ctx_udata, H5AC_WRITE)))
+    if(NULL == (hdr = H5EA__hdr_protect(f, dxpl_id, ea_addr, ctx_udata, H5AC__NO_FLAGS_SET)))
 	H5E_THROW(H5E_CANTPROTECT, "unable to load extensible array header")
 
     /* Point extensible array wrapper at header and bump it's ref count */
@@ -209,7 +209,7 @@ H5EA_open(H5F_t *f, hid_t dxpl_id, haddr_t ea_addr, void *ctx_udata))
 #ifdef QAK
 HDfprintf(stderr, "%s: ea_addr = %a\n", FUNC, ea_addr);
 #endif /* QAK */
-    if(NULL == (hdr = H5EA__hdr_protect(f, dxpl_id, ea_addr, ctx_udata, H5AC_READ)))
+    if(NULL == (hdr = H5EA__hdr_protect(f, dxpl_id, ea_addr, ctx_udata, H5AC__READ_ONLY_FLAG)))
         H5E_THROW(H5E_CANTPROTECT, "unable to load extensible array header, address = %llu", (unsigned long long)ea_addr)
 
     /* Check for pending array deletion */
@@ -333,7 +333,7 @@ END_FUNC(PRIV)  /* end H5EA_get_addr() */
  */
 BEGIN_FUNC(STATIC, ERR,
 herr_t, SUCCEED, FAIL,
-H5EA__lookup_elmt(const H5EA_t *ea, hid_t dxpl_id, hsize_t idx, H5AC_protect_t thing_acc,
+H5EA__lookup_elmt(const H5EA_t *ea, hid_t dxpl_id, hsize_t idx, unsigned thing_acc,
     void **thing, uint8_t **thing_elmt_buf, hsize_t *thing_elmt_idx,
     H5EA__unprotect_func_t *thing_unprot_func))
 
@@ -362,6 +362,9 @@ HDfprintf(stderr, "%s: Index %Hu\n", FUNC, idx);
     HDassert(thing_elmt_buf);
     HDassert(thing_unprot_func);
 
+    /* only the H5AC__READ_ONLY_FLAG may be set in thing_acc */
+    HDassert((thing_acc & (unsigned)(~H5AC__READ_ONLY_FLAG)) == 0);
+
     /* Set the shared array header's file context for this operation */
     hdr->f = ea->f;
 
@@ -377,7 +380,7 @@ HDfprintf(stderr, "%s: Index %Hu\n", FUNC, idx);
 HDfprintf(stderr, "%s: Index block address not defined!\n", FUNC, idx);
 #endif /* QAK */
         /* Check if we are allowed to create the thing */
-        if(H5AC_WRITE == thing_acc) {
+        if(0 == (thing_acc & H5AC__READ_ONLY_FLAG)) { /* i.e. r/w access */
             /* Create the index block */
             hdr->idx_blk_addr = H5EA__iblock_create(hdr, dxpl_id, &stats_changed);
             if(!H5F_addr_defined(hdr->idx_blk_addr))
@@ -435,7 +438,7 @@ HDfprintf(stderr, "%s: dblk_idx = %u, iblock->ndblk_addrs = %Zu\n", FUNC, dblk_i
             /* Check if the data block has been allocated on disk yet */
             if(!H5F_addr_defined(iblock->dblk_addrs[dblk_idx])) {
                 /* Check if we are allowed to create the thing */
-                if(H5AC_WRITE == thing_acc) {
+                if(0 == (thing_acc & H5AC__READ_ONLY_FLAG)) { /* i.e. r/w access */
                     haddr_t dblk_addr;        /* Address of data block created */
                     hsize_t dblk_off;         /* Offset of data block in array */
 
@@ -475,7 +478,7 @@ HDfprintf(stderr, "%s: dblk_idx = %u, iblock->ndblk_addrs = %Zu\n", FUNC, dblk_i
             /* Check if the super block has been allocated on disk yet */
             if(!H5F_addr_defined(iblock->sblk_addrs[sblk_off])) {
                 /* Check if we are allowed to create the thing */
-                if(H5AC_WRITE == thing_acc) {
+                if(0 == (thing_acc & H5AC__READ_ONLY_FLAG)) { /* i.e. r/w access */
                     haddr_t sblk_addr;        /* Address of data block created */
 
                     /* Create super block */
@@ -508,7 +511,7 @@ HDfprintf(stderr, "%s: dblk_idx = %u, sblock->ndblks = %Zu\n", FUNC, dblk_idx, s
             /* Check if the data block has been allocated on disk yet */
             if(!H5F_addr_defined(sblock->dblk_addrs[dblk_idx])) {
                 /* Check if we are allowed to create the thing */
-                if(H5AC_WRITE == thing_acc) {
+                if(0 == (thing_acc & H5AC__READ_ONLY_FLAG)) { /* i.e. r/w access */
                     haddr_t dblk_addr;        /* Address of data block created */
                     hsize_t dblk_off;         /* Offset of data block in array */
 
@@ -568,7 +571,7 @@ HDfprintf(stderr, "%s: sblock->dblk_page_size = %Zu\n", FUNC, sblock->dblk_page_
                 /* Check if page has been initialized yet */
                 if(!H5VM_bit_get(sblock->page_init, page_init_idx)) {
                     /* Check if we are allowed to create the thing */
-                    if(H5AC_WRITE == thing_acc) {
+                    if(0 == (thing_acc & H5AC__READ_ONLY_FLAG)) { /* i.e. r/w access */
                         /* Create the data block page */
                         if(H5EA__dblk_page_create(hdr, dxpl_id, sblock, dblk_page_addr) < 0)
                             H5E_THROW(H5E_CANTCREATE, "unable to create data block page")
@@ -677,7 +680,7 @@ HDfprintf(stderr, "%s: Index %Hu\n", FUNC, idx);
     hdr->f = ea->f;
 
     /* Look up the array metadata containing the element we want to set */
-    if(H5EA__lookup_elmt(ea, dxpl_id, idx, H5AC_WRITE, &thing, &thing_elmt_buf, &thing_elmt_idx, &thing_unprot_func) < 0)
+    if(H5EA__lookup_elmt(ea, dxpl_id, idx, H5AC__NO_FLAGS_SET, &thing, &thing_elmt_buf, &thing_elmt_idx, &thing_unprot_func) < 0)
         H5E_THROW(H5E_CANTPROTECT, "unable to protect array metadata")
 
     /* Sanity check */
@@ -762,7 +765,7 @@ HDfprintf(stderr, "%s: Index block address is: %a\n", FUNC, hdr->idx_blk_addr);
         hdr->f = ea->f;
 
         /* Look up the array metadata containing the element we want to set */
-        if(H5EA__lookup_elmt(ea, dxpl_id, idx, H5AC_READ, &thing, &thing_elmt_buf, &thing_elmt_idx, &thing_unprot_func) < 0)
+        if(H5EA__lookup_elmt(ea, dxpl_id, idx, H5AC__READ_ONLY_FLAG, &thing, &thing_elmt_buf, &thing_elmt_idx, &thing_unprot_func) < 0)
             H5E_THROW(H5E_CANTPROTECT, "unable to protect array metadata")
 
         /* Check if the thing holding the element has been created yet */
@@ -905,7 +908,7 @@ HDfprintf(stderr, "%s: Index %Hu\n", FUNC, idx);
     HDassert(ea);
 
     /* Look up the array metadata containing the element we want to set */
-    if(H5EA__lookup_elmt(ea, dxpl_id, idx, H5AC_WRITE, &thing, &thing_elmt_buf, &thing_elmt_idx, &thing_unprot_func) < 0)
+    if(H5EA__lookup_elmt(ea, dxpl_id, idx, H5AC__NO_FLAGS_SET, &thing, &thing_elmt_buf, &thing_elmt_idx, &thing_unprot_func) < 0)
         H5E_THROW(H5E_CANTPROTECT, "unable to protect array metadata")
 
     /* Sanity check */
@@ -960,7 +963,7 @@ HDfprintf(stderr, "%s: Index %Hu\n", FUNC, idx);
     HDassert(ea);
 
     /* Look up the array metadata containing the element we want to set */
-    if(H5EA__lookup_elmt(ea, dxpl_id, idx, H5AC_READ, &thing, &thing_elmt_buf, &thing_elmt_idx, &thing_unprot_func) < 0)
+    if(H5EA__lookup_elmt(ea, dxpl_id, idx, H5AC__READ_ONLY_FLAG, &thing, &thing_elmt_buf, &thing_elmt_idx, &thing_unprot_func) < 0)
         H5E_THROW(H5E_CANTPROTECT, "unable to protect array metadata")
 
     /* Sanity check */
@@ -1048,7 +1051,7 @@ HDfprintf(stderr, "%s: Called\n", FUNC);
 
         /* Lock the array header into memory */
         /* (OK to pass in NULL for callback context, since we know the header must be in the cache) */
-        if(NULL == (hdr = H5EA__hdr_protect(ea->f, dxpl_id, ea_addr, NULL, H5AC_WRITE)))
+        if(NULL == (hdr = H5EA__hdr_protect(ea->f, dxpl_id, ea_addr, NULL, H5AC__NO_FLAGS_SET)))
             H5E_THROW(H5E_CANTLOAD, "unable to load extensible array header")
 
         /* Set the shared array header's file context for this operation */
@@ -1112,7 +1115,7 @@ H5EA_delete(H5F_t *f, hid_t dxpl_id, haddr_t ea_addr, void *ctx_udata))
 #ifdef QAK
 HDfprintf(stderr, "%s: ea_addr = %a\n", FUNC, ea_addr);
 #endif /* QAK */
-    if(NULL == (hdr = H5EA__hdr_protect(f, dxpl_id, ea_addr, ctx_udata, H5AC_WRITE)))
+    if(NULL == (hdr = H5EA__hdr_protect(f, dxpl_id, ea_addr, ctx_udata, H5AC__NO_FLAGS_SET)))
         H5E_THROW(H5E_CANTPROTECT, "unable to protect extensible array header, address = %llu", (unsigned long long)ea_addr)
 
     /* Check for files using shared array header */
diff --git a/src/H5EAcache.c b/src/H5EAcache.c
index 70686fb..0d83fb3 100644
--- a/src/H5EAcache.c
+++ b/src/H5EAcache.c
@@ -57,13 +57,6 @@
 #define H5EA_SBLOCK_VERSION     0               /* Super block */
 #define H5EA_DBLOCK_VERSION     0               /* Data block */
 
-/* Size of stack buffer for serialization buffers */
-#define H5EA_HDR_BUF_SIZE       512
-#define H5EA_IBLOCK_BUF_SIZE    512
-#define H5EA_SBLOCK_BUF_SIZE    512
-#define H5EA_DBLOCK_BUF_SIZE    512
-#define H5EA_DBLK_PAGE_BUF_SIZE 512
-
 
 /******************/
 /* Local Typedefs */
@@ -80,35 +73,59 @@
 /********************/
 
 /* Metadata cache (H5AC) callbacks */
-static H5EA_hdr_t *H5EA__cache_hdr_load(H5F_t *f, hid_t dxpl_id, haddr_t addr, void *udata);
-static herr_t H5EA__cache_hdr_flush(H5F_t *f, hid_t dxpl_id, hbool_t destroy, haddr_t addr, H5EA_hdr_t *hdr, unsigned * flags_ptr);
-static herr_t H5EA__cache_hdr_clear(H5F_t *f, H5EA_hdr_t *hdr, hbool_t destroy);
-static herr_t H5EA__cache_hdr_size(const H5F_t *f, const H5EA_hdr_t *hdr, size_t *size_ptr);
-static herr_t H5EA__cache_hdr_dest(H5F_t *f, H5EA_hdr_t *hdr);
-static H5EA_iblock_t *H5EA__cache_iblock_load(H5F_t *f, hid_t dxpl_id, haddr_t addr, void *udata);
-static herr_t H5EA__cache_iblock_flush(H5F_t *f, hid_t dxpl_id, hbool_t destroy, haddr_t addr, H5EA_iblock_t *iblock, unsigned * flags_ptr);
-static herr_t H5EA__cache_iblock_clear(H5F_t *f, H5EA_iblock_t *iblock, hbool_t destroy);
-static herr_t H5EA__cache_iblock_notify(H5AC_notify_action_t action, H5EA_iblock_t *iblock);
-static herr_t H5EA__cache_iblock_size(const H5F_t *f, const H5EA_iblock_t *iblock, size_t *size_ptr);
-static herr_t H5EA__cache_iblock_dest(H5F_t *f, H5EA_iblock_t *iblock);
-static H5EA_sblock_t *H5EA__cache_sblock_load(H5F_t *f, hid_t dxpl_id, haddr_t addr, void *udata);
-static herr_t H5EA__cache_sblock_flush(H5F_t *f, hid_t dxpl_id, hbool_t destroy, haddr_t addr, H5EA_sblock_t *sblock, unsigned * flags_ptr);
-static herr_t H5EA__cache_sblock_clear(H5F_t *f, H5EA_sblock_t *sblock, hbool_t destroy);
-static herr_t H5EA__cache_sblock_size(const H5F_t *f, const H5EA_sblock_t *sblock, size_t *size_ptr);
-static herr_t H5EA__cache_sblock_notify(H5AC_notify_action_t action, H5EA_sblock_t *sblock);
-static herr_t H5EA__cache_sblock_dest(H5F_t *f, H5EA_sblock_t *sblock);
-static H5EA_dblock_t *H5EA__cache_dblock_load(H5F_t *f, hid_t dxpl_id, haddr_t addr, void *udata);
-static herr_t H5EA__cache_dblock_flush(H5F_t *f, hid_t dxpl_id, hbool_t destroy, haddr_t addr, H5EA_dblock_t *dblock, unsigned * flags_ptr);
-static herr_t H5EA__cache_dblock_clear(H5F_t *f, H5EA_dblock_t *dblock, hbool_t destroy);
-static herr_t H5EA__cache_dblock_size(const H5F_t *f, const H5EA_dblock_t *dblock, size_t *size_ptr);
-static herr_t H5EA__cache_dblock_notify(H5AC_notify_action_t action, H5EA_dblock_t *dblock);
-static herr_t H5EA__cache_dblock_dest(H5F_t *f, H5EA_dblock_t *dblock);
-static H5EA_dblk_page_t *H5EA__cache_dblk_page_load(H5F_t *f, hid_t dxpl_id, haddr_t addr, void *udata);
-static herr_t H5EA__cache_dblk_page_flush(H5F_t *f, hid_t dxpl_id, hbool_t destroy, haddr_t addr, H5EA_dblk_page_t *dblk_page, unsigned * flags_ptr);
-static herr_t H5EA__cache_dblk_page_clear(H5F_t *f, H5EA_dblk_page_t *dblk_page, hbool_t destroy);
-static herr_t H5EA__cache_dblk_page_size(const H5F_t *f, const H5EA_dblk_page_t *dblk_page, size_t *size_ptr);
-static herr_t H5EA__cache_dblk_page_notify(H5AC_notify_action_t action, H5EA_dblk_page_t *dblk_page);
-static herr_t H5EA__cache_dblk_page_dest(H5F_t *f, H5EA_dblk_page_t *dblk_page);
+static herr_t H5EA__cache_hdr_get_load_size(const void *udata, size_t *image_len);
+static void *H5EA__cache_hdr_deserialize(const void *image, size_t len,
+    void *udata, hbool_t *dirty);
+static herr_t H5EA__cache_hdr_image_len(const void *thing, size_t *image_len,
+    hbool_t *compressed_ptr, size_t *compressed_image_len_ptr);
+static herr_t H5EA__cache_hdr_serialize(const H5F_t *f, void *image, size_t len,
+    void *thing);
+static herr_t H5EA__cache_hdr_free_icr(void *thing);
+
+static herr_t H5EA__cache_iblock_get_load_size(const void *udata, size_t *image_len);
+static void *H5EA__cache_iblock_deserialize(const void *image, size_t len,
+    void *udata, hbool_t *dirty);
+static herr_t H5EA__cache_iblock_image_len(const void *thing, 
+    size_t *image_len, hbool_t *compressed_ptr, 
+    size_t *compressed_image_len_ptr);
+static herr_t H5EA__cache_iblock_serialize(const H5F_t *f, void *image, size_t len,
+    void *thing);
+static herr_t H5EA__cache_iblock_notify(H5AC_notify_action_t action, void *thing);
+static herr_t H5EA__cache_iblock_free_icr(void *thing);
+
+static herr_t H5EA__cache_sblock_get_load_size(const void *udata, size_t *image_len);
+static void *H5EA__cache_sblock_deserialize(const void *image, size_t len,
+    void *udata, hbool_t *dirty);
+static herr_t H5EA__cache_sblock_image_len(const void *thing, 
+    size_t *image_len, hbool_t *compressed_ptr, 
+    size_t *compressed_image_len_ptr);
+static herr_t H5EA__cache_sblock_serialize(const H5F_t *f, void *image, size_t len,
+    void *thing);
+static herr_t H5EA__cache_sblock_notify(H5AC_notify_action_t action, void *thing);
+static herr_t H5EA__cache_sblock_free_icr(void *thing);
+
+static herr_t H5EA__cache_dblock_get_load_size(const void *udata, size_t *image_len);
+static void *H5EA__cache_dblock_deserialize(const void *image, size_t len,
+    void *udata, hbool_t *dirty);
+static herr_t H5EA__cache_dblock_image_len(const void *thing, 
+    size_t *image_len, hbool_t *compressed_ptr, 
+    size_t *compressed_image_len_ptr);
+static herr_t H5EA__cache_dblock_serialize(const H5F_t *f, void *image, size_t len,
+    void *thing);
+static herr_t H5EA__cache_dblock_notify(H5AC_notify_action_t action, void *thing);
+static herr_t H5EA__cache_dblock_free_icr(void *thing);
+static herr_t H5EA__cache_dblock_fsf_size(const void *thing, size_t *fsf_size);
+
+static herr_t H5EA__cache_dblk_page_get_load_size(const void *udata, size_t *image_len);
+static void *H5EA__cache_dblk_page_deserialize(const void *image, size_t len,
+    void *udata, hbool_t *dirty);
+static herr_t H5EA__cache_dblk_page_image_len(const void *thing, 
+    size_t *image_len, hbool_t *compressed_ptr, 
+    size_t *compressed_image_len_ptr);
+static herr_t H5EA__cache_dblk_page_serialize(const H5F_t *f, void *image, size_t len,
+    void *thing);
+static herr_t H5EA__cache_dblk_page_notify(H5AC_notify_action_t action, void *thing);
+static herr_t H5EA__cache_dblk_page_free_icr(void *thing);
 
 
 /*********************/
@@ -117,57 +134,87 @@ static herr_t H5EA__cache_dblk_page_dest(H5F_t *f, H5EA_dblk_page_t *dblk_page);
 
 /* H5EA header inherits cache-like properties from H5AC */
 const H5AC_class_t H5AC_EARRAY_HDR[1] = {{
-    H5AC_EARRAY_HDR_ID,
-    (H5AC_load_func_t)H5EA__cache_hdr_load,
-    (H5AC_flush_func_t)H5EA__cache_hdr_flush,
-    (H5AC_dest_func_t)H5EA__cache_hdr_dest,
-    (H5AC_clear_func_t)H5EA__cache_hdr_clear,
-    (H5AC_notify_func_t)NULL,
-    (H5AC_size_func_t)H5EA__cache_hdr_size,
+    H5AC_EARRAY_HDR_ID,                 /* Metadata client ID */
+    "Extensible Array Header",          /* Metadata client name (for debugging) */
+    H5FD_MEM_EARRAY_HDR,                /* File space memory type for client */
+    H5AC__CLASS_NO_FLAGS_SET,           /* Client class behavior flags */
+    H5EA__cache_hdr_get_load_size,      /* 'get_load_size' callback */
+    H5EA__cache_hdr_deserialize,        /* 'deserialize' callback */
+    H5EA__cache_hdr_image_len,          /* 'image_len' callback */
+    NULL,                               /* 'pre_serialize' callback */
+    H5EA__cache_hdr_serialize,          /* 'serialize' callback */
+    NULL,                               /* 'notify' callback */
+    H5EA__cache_hdr_free_icr,           /* 'free_icr' callback */
+    NULL,				/* 'clear' callback */
+    NULL,                               /* 'fsf_size' callback */
 }};
 
 /* H5EA index block inherits cache-like properties from H5AC */
 const H5AC_class_t H5AC_EARRAY_IBLOCK[1] = {{
-    H5AC_EARRAY_IBLOCK_ID,
-    (H5AC_load_func_t)H5EA__cache_iblock_load,
-    (H5AC_flush_func_t)H5EA__cache_iblock_flush,
-    (H5AC_dest_func_t)H5EA__cache_iblock_dest,
-    (H5AC_clear_func_t)H5EA__cache_iblock_clear,
-    (H5AC_notify_func_t)H5EA__cache_iblock_notify,
-    (H5AC_size_func_t)H5EA__cache_iblock_size,
+    H5AC_EARRAY_IBLOCK_ID,              /* Metadata client ID */
+    "Extensible Array Index Block",     /* Metadata client name (for debugging) */
+    H5FD_MEM_EARRAY_IBLOCK,             /* File space memory type for client */
+    H5AC__CLASS_NO_FLAGS_SET,           /* Client class behavior flags */
+    H5EA__cache_iblock_get_load_size,   /* 'get_load_size' callback */
+    H5EA__cache_iblock_deserialize,     /* 'deserialize' callback */
+    H5EA__cache_iblock_image_len,       /* 'image_len' callback */
+    NULL,                               /* 'pre_serialize' callback */
+    H5EA__cache_iblock_serialize,       /* 'serialize' callback */
+    H5EA__cache_iblock_notify,          /* 'notify' callback */
+    H5EA__cache_iblock_free_icr,        /* 'free_icr' callback */
+    NULL,				/* 'clear' callback */
+    NULL,                               /* 'fsf_size' callback */
 }};
 
 /* H5EA super block inherits cache-like properties from H5AC */
 const H5AC_class_t H5AC_EARRAY_SBLOCK[1] = {{
-    H5AC_EARRAY_SBLOCK_ID,
-    (H5AC_load_func_t)H5EA__cache_sblock_load,
-    (H5AC_flush_func_t)H5EA__cache_sblock_flush,
-    (H5AC_dest_func_t)H5EA__cache_sblock_dest,
-    (H5AC_clear_func_t)H5EA__cache_sblock_clear,
-    (H5AC_notify_func_t)H5EA__cache_sblock_notify,
-    (H5AC_size_func_t)H5EA__cache_sblock_size,
+    H5AC_EARRAY_SBLOCK_ID,              /* Metadata client ID */
+    "Extensible Array Super Block",     /* Metadata client name (for debugging) */
+    H5FD_MEM_EARRAY_SBLOCK,             /* File space memory type for client */
+    H5AC__CLASS_NO_FLAGS_SET,           /* Client class behavior flags */
+    H5EA__cache_sblock_get_load_size,   /* 'get_load_size' callback */
+    H5EA__cache_sblock_deserialize,     /* 'deserialize' callback */
+    H5EA__cache_sblock_image_len,       /* 'image_len' callback */
+    NULL,                               /* 'pre_serialize' callback */
+    H5EA__cache_sblock_serialize,       /* 'serialize' callback */
+    H5EA__cache_sblock_notify,          /* 'notify' callback */
+    H5EA__cache_sblock_free_icr,        /* 'free_icr' callback */
+    NULL,				/* 'clear' callback */
+    NULL,                               /* 'fsf_size' callback */
 }};
 
 /* H5EA data block inherits cache-like properties from H5AC */
 const H5AC_class_t H5AC_EARRAY_DBLOCK[1] = {{
-    H5AC_EARRAY_DBLOCK_ID,
-    (H5AC_load_func_t)H5EA__cache_dblock_load,
-    (H5AC_flush_func_t)H5EA__cache_dblock_flush,
-    (H5AC_dest_func_t)H5EA__cache_dblock_dest,
-    (H5AC_clear_func_t)H5EA__cache_dblock_clear,
-    (H5AC_notify_func_t)H5EA__cache_dblock_notify,
-    (H5AC_size_func_t)H5EA__cache_dblock_size,
+    H5AC_EARRAY_DBLOCK_ID,              /* Metadata client ID */
+    "Extensible Array Data Block",      /* Metadata client name (for debugging) */
+    H5FD_MEM_EARRAY_DBLOCK,             /* File space memory type for client */
+    H5AC__CLASS_NO_FLAGS_SET,           /* Client class behavior flags */
+    H5EA__cache_dblock_get_load_size,   /* 'get_load_size' callback */
+    H5EA__cache_dblock_deserialize,     /* 'deserialize' callback */
+    H5EA__cache_dblock_image_len,       /* 'image_len' callback */
+    NULL,                               /* 'pre_serialize' callback */
+    H5EA__cache_dblock_serialize,       /* 'serialize' callback */
+    H5EA__cache_dblock_notify,          /* 'notify' callback */
+    H5EA__cache_dblock_free_icr,        /* 'free_icr' callback */
+    NULL,				/* 'clear' callback */
+    H5EA__cache_dblock_fsf_size,        /* 'fsf_size' callback */
 }};
 
 /* H5EA data block page inherits cache-like properties from H5AC */
 const H5AC_class_t H5AC_EARRAY_DBLK_PAGE[1] = {{
-    H5AC_EARRAY_DBLK_PAGE_ID,
-    (H5AC_load_func_t)H5EA__cache_dblk_page_load,
-    (H5AC_flush_func_t)H5EA__cache_dblk_page_flush,
-    (H5AC_dest_func_t)H5EA__cache_dblk_page_dest,
-    (H5AC_clear_func_t)H5EA__cache_dblk_page_clear,
-    (H5AC_notify_func_t)H5EA__cache_dblk_page_notify,
-    (H5AC_size_func_t)H5EA__cache_dblk_page_size,
+    H5AC_EARRAY_DBLK_PAGE_ID,           /* Metadata client ID */
+    "Extensible Array Data Block Page", /* Metadata client name (for debugging) */
+    H5FD_MEM_EARRAY_DBLK_PAGE,          /* File space memory type for client */
+    H5AC__CLASS_NO_FLAGS_SET,           /* Client class behavior flags */
+    H5EA__cache_dblk_page_get_load_size, /* 'get_load_size' callback */
+    H5EA__cache_dblk_page_deserialize,  /* 'deserialize' callback */
+    H5EA__cache_dblk_page_image_len,    /* 'image_len' callback */
+    NULL,                               /* 'pre_serialize' callback */
+    H5EA__cache_dblk_page_serialize,    /* 'serialize' callback */
+    H5EA__cache_dblk_page_notify,       /* 'notify' callback */
+    H5EA__cache_dblk_page_free_icr,     /* 'free_icr' callback */
+    NULL,				/* 'clear' callback */
+    NULL,                               /* 'fsf_size' callback */
 }};
 
 
@@ -183,97 +230,111 @@ const H5AC_class_t H5AC_EARRAY_DBLK_PAGE[1] = {{
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5EA__cache_hdr_load
+ * Function:    H5EA__cache_hdr_get_load_size
+ *
+ * Purpose:     Compute the size of the data structure on disk.
+ *
+ * Return:      Non-negative on success/Negative on failure
+ *
+ * Programmer:  Quincey Koziol
+ *              koziol@hdfgroup.org
+ *              July 16, 2013
+ *
+ *-------------------------------------------------------------------------
+ */
+BEGIN_FUNC(STATIC, NOERR,
+herr_t, SUCCEED, -,
+H5EA__cache_hdr_get_load_size(const void *_udata, size_t *image_len))
+
+    /* Local variables */
+    const H5EA_hdr_cache_ud_t *udata = (const H5EA_hdr_cache_ud_t *)_udata; /* User data for callback */
+
+    /* Check arguments */
+    HDassert(udata);
+    HDassert(udata->f);
+    HDassert(H5F_addr_defined(udata->addr));
+    HDassert(image_len);
+
+    /* Set the image length size */
+    *image_len = (size_t)H5EA_HEADER_SIZE_FILE(udata->f);
+
+END_FUNC(STATIC)   /* end H5EA__cache_hdr_get_load_size() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:	H5EA__cache_hdr_deserialize
  *
- * Purpose:	Loads an extensible array header from the disk.
+ * Purpose:	Loads a data structure from the disk.
  *
- * Return:	Success:	Pointer to a new extensible array
+ * Return:	Success:	Pointer to a new B-tree.
  *		Failure:	NULL
  *
  * Programmer:	Quincey Koziol
- *		koziol@hdfgroup.org
- *		Aug 26 2008
+ *              koziol@hdfgroup.org
+ *              July 16, 2013
  *
  *-------------------------------------------------------------------------
  */
 BEGIN_FUNC(STATIC, ERR,
-H5EA_hdr_t *, NULL, NULL,
-H5EA__cache_hdr_load(H5F_t *f, hid_t dxpl_id, haddr_t addr, void *udata))
+void *, NULL, NULL,
+H5EA__cache_hdr_deserialize(const void *_image, size_t len, void *_udata,
+    hbool_t H5_ATTR_UNUSED *dirty))
 
     /* Local variables */
     H5EA_cls_id_t       id;		/* ID of extensible array class, as found in file */
     H5EA_hdr_t		*hdr = NULL;    /* Extensible array info */
-    size_t		size;           /* Header size */
-    H5WB_t              *wb = NULL;     /* Wrapped buffer for header data */
-    uint8_t             hdr_buf[H5EA_HDR_BUF_SIZE]; /* Buffer for header */
-    uint8_t		*buf;           /* Pointer to header buffer */
-    const uint8_t	*p;             /* Pointer into raw data buffer */
+    H5EA_hdr_cache_ud_t *udata = (H5EA_hdr_cache_ud_t *)_udata;
+    const uint8_t	*image = (const uint8_t *)_image;       /* Pointer into raw data buffer */
     uint32_t            stored_chksum;  /* Stored metadata checksum value */
     uint32_t            computed_chksum; /* Computed metadata checksum value */
 
     /* Check arguments */
-    HDassert(f);
-    HDassert(H5F_addr_defined(addr));
+    HDassert(image);
+    HDassert(udata);
+    HDassert(udata->f);
+    HDassert(H5F_addr_defined(udata->addr));
 
     /* Allocate space for the extensible array data structure */
-    if(NULL == (hdr = H5EA__hdr_alloc(f)))
+    if(NULL == (hdr = H5EA__hdr_alloc(udata->f)))
 	H5E_THROW(H5E_CANTALLOC, "memory allocation failed for extensible array shared header")
 
     /* Set the extensible array header's address */
-    hdr->addr = addr;
-
-    /* Wrap the local buffer for serialized info */
-    if(NULL == (wb = H5WB_wrap(hdr_buf, sizeof(hdr_buf))))
-	H5E_THROW(H5E_CANTINIT, "can't wrap buffer")
-
-    /* Compute the 'base' size of the extensible array header on disk */
-    size = H5EA_HEADER_SIZE_HDR(hdr);
-
-    /* Get a pointer to a buffer that's large enough for serialized header */
-    if(NULL == (buf = (uint8_t *)H5WB_actual(wb, size)))
-	H5E_THROW(H5E_CANTGET, "can't get actual buffer")
-
-    /* Read header from disk */
-    if(H5F_block_read(f, H5FD_MEM_EARRAY_HDR, addr, size, dxpl_id, buf) < 0)
-	H5E_THROW(H5E_READERROR, "can't read extensible array header")
-
-    /* Get temporary pointer to serialized header */
-    p = buf;
+    hdr->addr = udata->addr;
 
     /* Magic number */
-    if(HDmemcmp(p, H5EA_HDR_MAGIC, (size_t)H5_SIZEOF_MAGIC))
+    if(HDmemcmp(image, H5EA_HDR_MAGIC, (size_t)H5_SIZEOF_MAGIC))
 	H5E_THROW(H5E_BADVALUE, "wrong extensible array header signature")
-    p += H5_SIZEOF_MAGIC;
+    image += H5_SIZEOF_MAGIC;
 
     /* Version */
-    if(*p++ != H5EA_HDR_VERSION)
+    if(*image++ != H5EA_HDR_VERSION)
 	H5E_THROW(H5E_VERSION, "wrong extensible array header version")
 
     /* Extensible array class */
-    id = (H5EA_cls_id_t)*p++;
+    id = (H5EA_cls_id_t)*image++;
     if(id >= H5EA_NUM_CLS_ID)
 	H5E_THROW(H5E_BADTYPE, "incorrect extensible array class")
     hdr->cparam.cls = H5EA_client_class_g[id];
 
     /* General array creation/configuration information */
-    hdr->cparam.raw_elmt_size = *p++;          /* Element size in file (in bytes) */
-    hdr->cparam.max_nelmts_bits = *p++;        /* Log2(Max. # of elements in array) - i.e. # of bits needed to store max. # of elements */
-    hdr->cparam.idx_blk_elmts = *p++;          /* # of elements to store in index block */
-    hdr->cparam.data_blk_min_elmts = *p++;     /* Min. # of elements per data block */
-    hdr->cparam.sup_blk_min_data_ptrs = *p++;  /* Min. # of data block pointers for a super block */
-    hdr->cparam.max_dblk_page_nelmts_bits = *p++;  /* Log2(Max. # of elements in data block page) - i.e. # of bits needed to store max. # of elements in data block page */
+    hdr->cparam.raw_elmt_size = *image++;          /* Element size in file (in bytes) */
+    hdr->cparam.max_nelmts_bits = *image++;        /* Log2(Max. # of elements in array) - i.e. # of bits needed to store max. # of elements */
+    hdr->cparam.idx_blk_elmts = *image++;          /* # of elements to store in index block */
+    hdr->cparam.data_blk_min_elmts = *image++;     /* Min. # of elements per data block */
+    hdr->cparam.sup_blk_min_data_ptrs = *image++;  /* Min. # of data block pointers for a super block */
+    hdr->cparam.max_dblk_page_nelmts_bits = *image++;  /* Log2(Max. # of elements in data block page) - i.e. # of bits needed to store max. # of elements in data block page */
 
     /* Array statistics */
-    hdr->stats.computed.hdr_size = size;                        /* Size of header in file */
-    H5F_DECODE_LENGTH(f, p, hdr->stats.stored.nsuper_blks);    /* Number of super blocks created */
-    H5F_DECODE_LENGTH(f, p, hdr->stats.stored.super_blk_size); /* Size of super blocks created */
-    H5F_DECODE_LENGTH(f, p, hdr->stats.stored.ndata_blks);     /* Number of data blocks created */
-    H5F_DECODE_LENGTH(f, p, hdr->stats.stored.data_blk_size);  /* Size of data blocks created */
-    H5F_DECODE_LENGTH(f, p, hdr->stats.stored.max_idx_set);    /* Max. index set (+1) */
-    H5F_DECODE_LENGTH(f, p, hdr->stats.stored.nelmts);         /* Number of elements 'realized' */
+    hdr->stats.computed.hdr_size = len;                        /* Size of header in file */
+    H5F_DECODE_LENGTH(udata->f, image, hdr->stats.stored.nsuper_blks);    /* Number of super blocks created */
+    H5F_DECODE_LENGTH(udata->f, image, hdr->stats.stored.super_blk_size); /* Size of super blocks created */
+    H5F_DECODE_LENGTH(udata->f, image, hdr->stats.stored.ndata_blks);     /* Number of data blocks created */
+    H5F_DECODE_LENGTH(udata->f, image, hdr->stats.stored.data_blk_size);  /* Size of data blocks created */
+    H5F_DECODE_LENGTH(udata->f, image, hdr->stats.stored.max_idx_set);    /* Max. index set (+1) */
+    H5F_DECODE_LENGTH(udata->f, image, hdr->stats.stored.nelmts);         /* Number of elements 'realized' */
 
     /* Internal information */
-    H5F_addr_decode(f, &p, &hdr->idx_blk_addr); /* Address of index block */
+    H5F_addr_decode(udata->f, &image, &hdr->idx_blk_addr); /* Address of index block */
 
     /* Index block statistics */
     if(H5F_addr_defined(hdr->idx_blk_addr)) {
@@ -298,26 +359,26 @@ H5EA__cache_hdr_load(H5F_t *f, hid_t dxpl_id, haddr_t addr, void *udata))
 
     /* Sanity check */
     /* (allow for checksum not decoded yet) */
-    HDassert((size_t)(p - buf) == (size - H5EA_SIZEOF_CHKSUM));
+    HDassert((size_t)(image - (const uint8_t *)_image) == (len - H5EA_SIZEOF_CHKSUM));
 
     /* Compute checksum on entire header */
     /* (including the filter information, if present) */
-    computed_chksum = H5_checksum_metadata(buf, (size_t)(p - buf), 0);
+    computed_chksum = H5_checksum_metadata(_image, (size_t)(image - (const uint8_t *)_image), 0);
 
     /* Metadata checksum */
-    UINT32DECODE(p, stored_chksum);
-
-    /* Sanity check */
-    HDassert((size_t)(p - buf) == size);
+    UINT32DECODE(image, stored_chksum);
 
     /* Verify checksum */
     if(stored_chksum != computed_chksum)
 	H5E_THROW(H5E_BADVALUE, "incorrect metadata checksum for extensible array header")
 
+    /* Sanity check */
+    HDassert((size_t)(image - (const uint8_t *)_image) == len);
+
     /* Finish initializing extensible array header */
-    if(H5EA__hdr_init(hdr, udata) < 0)
+    if(H5EA__hdr_init(hdr, udata->ctx_udata) < 0)
 	H5E_THROW(H5E_CANTINIT, "initialization failed for extensible array header")
-    HDassert(hdr->size == size);
+    HDassert(hdr->size == len);
 
     /* Set return value */
     ret_value = hdr;
@@ -325,263 +386,211 @@ H5EA__cache_hdr_load(H5F_t *f, hid_t dxpl_id, haddr_t addr, void *udata))
 CATCH
 
     /* Release resources */
-    if(wb && H5WB_unwrap(wb) < 0)
-	H5E_THROW(H5E_CLOSEERROR, "can't close wrapped buffer")
     if(!ret_value)
         if(hdr && H5EA__hdr_dest(hdr) < 0)
             H5E_THROW(H5E_CANTFREE, "unable to destroy extensible array header")
 
-END_FUNC(STATIC)   /* end H5EA__cache_hdr_load() */
+END_FUNC(STATIC)   /* end H5EA__cache_hdr_deserialize() */
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5EA__cache_hdr_flush
+ * Function:    H5EA__cache_hdr_image_len
  *
- * Purpose:	Flushes a dirty extensible array header to disk.
+ * Purpose:     Compute the size of the data structure on disk.
  *
- * Return:	Non-negative on success/Negative on failure
+ * Return:      Non-negative on success/Negative on failure
  *
- * Programmer:	Quincey Koziol
- *		koziol@hdfgroup.org
- *		Aug 26 2008
+ * Programmer:  Quincey Koziol
+ *              koziol@hdfgroup.org
+ *              July 16, 2013
  *
  *-------------------------------------------------------------------------
  */
-BEGIN_FUNC(STATIC, ERR,
-herr_t, SUCCEED, FAIL,
-H5EA__cache_hdr_flush(H5F_t *f, hid_t dxpl_id, hbool_t destroy, haddr_t addr,
-    H5EA_hdr_t *hdr, unsigned H5_ATTR_UNUSED * flags_ptr))
+BEGIN_FUNC(STATIC, NOERR,
+herr_t, SUCCEED, -,
+H5EA__cache_hdr_image_len(const void *_thing, size_t *image_len,
+    hbool_t H5_ATTR_UNUSED *compressed_ptr, size_t H5_ATTR_UNUSED *compressed_image_len_ptr))
 
-    H5WB_t *wb = NULL;                  /* Wrapped buffer for header data */
-    uint8_t hdr_buf[H5EA_HDR_BUF_SIZE]; /* Buffer for header */
+    /* Local variables */
+    const H5EA_hdr_t *hdr = (const H5EA_hdr_t *)_thing;      /* Pointer to the object */
 
-    /* check arguments */
-    HDassert(f);
-    HDassert(H5F_addr_defined(addr));
+    /* Check arguments */
     HDassert(hdr);
+    HDassert(image_len);
 
-    if(hdr->cache_info.is_dirty) {
-        uint8_t	*buf;           /* Temporary raw data buffer */
-        uint8_t *p;             /* Pointer into raw data buffer */
-        size_t	size;           /* Header size on disk */
-        uint32_t metadata_chksum; /* Computed metadata checksum value */
-
-        /* Wrap the local buffer for serialized header info */
-        if(NULL == (wb = H5WB_wrap(hdr_buf, sizeof(hdr_buf))))
-            H5E_THROW(H5E_CANTINIT, "can't wrap buffer")
-
-        /* Compute the size of the array header on disk */
-        size = hdr->size;
-
-        /* Get a pointer to a buffer that's large enough for serialized header */
-        if(NULL == (buf = (uint8_t *)H5WB_actual(wb, size)))
-            H5E_THROW(H5E_CANTGET, "can't get actual buffer")
+    /* Set the image length size */
+    *image_len = hdr->size;
 
-        /* Get temporary pointer to serialized header */
-        p = buf;
+END_FUNC(STATIC)   /* end H5EA__cache_hdr_image_len() */
 
-        /* Magic number */
-        HDmemcpy(p, H5EA_HDR_MAGIC, (size_t)H5_SIZEOF_MAGIC);
-        p += H5_SIZEOF_MAGIC;
-
-        /* Version # */
-        *p++ = H5EA_HDR_VERSION;
+
+/*-------------------------------------------------------------------------
+ * Function:	H5EA__cache_hdr_serialize
+ *
+ * Purpose:	Flushes a dirty object to disk.
+ *
+ * Return:	Non-negative on success/Negative on failure
+ *
+ * Programmer:	Quincey Koziol
+ *              koziol@hdfgroup.org
+ *              July 16, 2013
+ *
+ *-------------------------------------------------------------------------
+ */
+BEGIN_FUNC(STATIC, NOERR,
+herr_t, SUCCEED, -,
+H5EA__cache_hdr_serialize(const H5F_t *f, void *_image, size_t H5_ATTR_UNUSED len,
+    void *_thing))
 
-        /* Extensible array type */
-        *p++ = hdr->cparam.cls->id;
+    /* Local variables */
+    H5EA_hdr_t *hdr = (H5EA_hdr_t *)_thing;      /* Pointer to the extensible array header */
+    uint8_t *image = (uint8_t *)_image;         /* Pointer into raw data buffer */
+    uint32_t metadata_chksum;   /* Computed metadata checksum value */
 
-        /* General array creation/configuration information */
-        *p++ = hdr->cparam.raw_elmt_size;          /* Element size in file (in bytes) */
-        *p++ = hdr->cparam.max_nelmts_bits;        /* Log2(Max. # of elements in array) - i.e. # of bits needed to store max. # of elements */
-        *p++ = hdr->cparam.idx_blk_elmts;          /* # of elements to store in index block */
-        *p++ = hdr->cparam.data_blk_min_elmts;     /* Min. # of elements per data block */
-        *p++ = hdr->cparam.sup_blk_min_data_ptrs;  /* Min. # of data block pointers for a super block */
-        *p++ = hdr->cparam.max_dblk_page_nelmts_bits;  /* Log2(Max. # of elements in data block page) - i.e. # of bits needed to store max. # of elements in data block page */
+    /* check arguments */
+    HDassert(f);
+    HDassert(image);
+    HDassert(hdr);
 
-        /* Array statistics */
-        H5F_ENCODE_LENGTH(f, p, hdr->stats.stored.nsuper_blks);    /* Number of super blocks created */
-        H5F_ENCODE_LENGTH(f, p, hdr->stats.stored.super_blk_size); /* Size of super blocks created */
-        H5F_ENCODE_LENGTH(f, p, hdr->stats.stored.ndata_blks);     /* Number of data blocks created */
-        H5F_ENCODE_LENGTH(f, p, hdr->stats.stored.data_blk_size);  /* Size of data blocks created */
-        H5F_ENCODE_LENGTH(f, p, hdr->stats.stored.max_idx_set);    /* Max. index set (+1) */
-        H5F_ENCODE_LENGTH(f, p, hdr->stats.stored.nelmts);         /* Number of elements 'realized' */
+    /* Magic number */
+    HDmemcpy(image, H5EA_HDR_MAGIC, (size_t)H5_SIZEOF_MAGIC);
+    image += H5_SIZEOF_MAGIC;
 
-        /* Internal information */
-        H5F_addr_encode(f, &p, hdr->idx_blk_addr);  /* Address of index block */
+    /* Version # */
+    *image++ = H5EA_HDR_VERSION;
 
-        /* Compute metadata checksum */
-        metadata_chksum = H5_checksum_metadata(buf, (size_t)(p - buf), 0);
+    /* Extensible array type */
+    *image++ = hdr->cparam.cls->id;
 
-        /* Metadata checksum */
-        UINT32ENCODE(p, metadata_chksum);
+    /* General array creation/configuration information */
+    *image++ = hdr->cparam.raw_elmt_size;          /* Element size in file (in bytes) */
+    *image++ = hdr->cparam.max_nelmts_bits;        /* Log2(Max. # of elements in array) - i.e. # of bits needed to store max. # of elements */
+    *image++ = hdr->cparam.idx_blk_elmts;          /* # of elements to store in index block */
+    *image++ = hdr->cparam.data_blk_min_elmts;     /* Min. # of elements per data block */
+    *image++ = hdr->cparam.sup_blk_min_data_ptrs;  /* Min. # of data block pointers for a super block */
+    *image++ = hdr->cparam.max_dblk_page_nelmts_bits;  /* Log2(Max. # of elements in data block page) - i.e. # of bits needed to store max. # of elements in data block page */
 
-	/* Write the array header. */
-        HDassert((size_t)(p - buf) == size);
-	if(H5F_block_write(f, H5FD_MEM_EARRAY_HDR, addr, size, dxpl_id, buf) < 0)
-            H5E_THROW(H5E_WRITEERROR, "unable to save extensible array header to disk")
+    /* Array statistics */
+    H5F_ENCODE_LENGTH(f, image, hdr->stats.stored.nsuper_blks);    /* Number of super blocks created */
+    H5F_ENCODE_LENGTH(f, image, hdr->stats.stored.super_blk_size); /* Size of super blocks created */
+    H5F_ENCODE_LENGTH(f, image, hdr->stats.stored.ndata_blks);     /* Number of data blocks created */
+    H5F_ENCODE_LENGTH(f, image, hdr->stats.stored.data_blk_size);  /* Size of data blocks created */
+    H5F_ENCODE_LENGTH(f, image, hdr->stats.stored.max_idx_set);    /* Max. index set (+1) */
+    H5F_ENCODE_LENGTH(f, image, hdr->stats.stored.nelmts);         /* Number of elements 'realized' */
 
-	hdr->cache_info.is_dirty = FALSE;
-    } /* end if */
+    /* Internal information */
+    H5F_addr_encode(f, &image, hdr->idx_blk_addr);  /* Address of index block */
 
-    if(destroy)
-        if(H5EA__cache_hdr_dest(f, hdr) < 0)
-            H5E_THROW(H5E_CANTFREE, "unable to destroy extensible array header")
+    /* Compute metadata checksum */
+    metadata_chksum = H5_checksum_metadata(_image, (size_t)(image - (uint8_t *)_image), 0);
 
-CATCH
+    /* Metadata checksum */
+    UINT32ENCODE(image, metadata_chksum);
 
-    /* Release resources */
-    if(wb && H5WB_unwrap(wb) < 0)
-	H5E_THROW(H5E_CLOSEERROR, "can't close wrapped buffer")
+    /* Sanity check */
+    HDassert((size_t)(image - (uint8_t *)_image) <= len);
 
-END_FUNC(STATIC)   /* end H5EA__cache_hdr_flush() */
+END_FUNC(STATIC)   /* end H5EA__cache_hdr_serialize() */
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5EA__cache_hdr_clear
+ * Function:	H5EA__cache_hdr_free_icr
  *
- * Purpose:	Mark a extensible array header in memory as non-dirty.
+ * Purpose:	Destroy/release an "in core representation" of a data
+ *              structure
  *
  * Return:	Non-negative on success/Negative on failure
  *
  * Programmer:	Quincey Koziol
- *		koziol@hdfgroup.org
- *		Aug 26 2008
+ *              koziol@hdfgroup.org
+ *              July 16, 2013
  *
  *-------------------------------------------------------------------------
  */
 BEGIN_FUNC(STATIC, ERR,
 herr_t, SUCCEED, FAIL,
-H5EA__cache_hdr_clear(H5F_t *f, H5EA_hdr_t *hdr, hbool_t destroy))
+H5EA__cache_hdr_free_icr(void *thing))
 
-    /* Sanity check */
-    HDassert(hdr);
-
-    /* Reset the dirty flag.  */
-    hdr->cache_info.is_dirty = FALSE;
+    /* Check arguments */
+    HDassert(thing);
 
-    if(destroy)
-        if(H5EA__cache_hdr_dest(f, hdr) < 0)
-            H5E_THROW(H5E_CANTFREE, "unable to destroy extensible array header")
+    /* Release the extensible array header */
+    if(H5EA__hdr_dest((H5EA_hdr_t *)thing) < 0)
+        H5E_THROW(H5E_CANTFREE, "can't free extensible array header")
 
 CATCH
 
-END_FUNC(STATIC)   /* end H5EA__cache_hdr_clear() */
+END_FUNC(STATIC)   /* end H5EA__cache_hdr_free_icr() */
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5EA__cache_hdr_size
+ * Function:    H5EA__cache_iblock_get_load_size
  *
- * Purpose:	Compute the size in bytes of a extensible array header
- *		on disk, and return it in *size_ptr.  On failure,
- *		the value of *size_ptr is undefined.
+ * Purpose:     Compute the size of the data structure on disk.
  *
- * Return:	Non-negative on success/Negative on failure
+ * Return:      Non-negative on success/Negative on failure
  *
- * Programmer:	Quincey Koziol
- *		koziol@hdfgroup.org
- *		Aug 26 2008
+ * Programmer:  Quincey Koziol
+ *              koziol@hdfgroup.org
+ *              July 17, 2013
  *
  *-------------------------------------------------------------------------
  */
-/* ARGSUSED */
 BEGIN_FUNC(STATIC, NOERR,
 herr_t, SUCCEED, -,
-H5EA__cache_hdr_size(const H5F_t H5_ATTR_UNUSED *f, const H5EA_hdr_t *hdr,
-    size_t *size_ptr))
-
-    /* Sanity check */
-    HDassert(f);
-    HDassert(hdr);
-    HDassert(size_ptr);
-
-    /* Set size value */
-    *size_ptr = hdr->size;
-
-END_FUNC(STATIC)   /* end H5EA__cache_hdr_size() */
+H5EA__cache_iblock_get_load_size(const void *_udata, size_t *image_len))
 
-
-/*-------------------------------------------------------------------------
- * Function:	H5EA__cache_hdr_dest
- *
- * Purpose:	Destroys an extensible array header in memory.
- *
- * Return:	Non-negative on success/Negative on failure
- *
- * Programmer:	Quincey Koziol
- *		koziol@hdfgroup.org
- *		Aug 26 2008
- *
- *-------------------------------------------------------------------------
- */
-/* ARGSUSED */
-BEGIN_FUNC(STATIC, ERR,
-herr_t, SUCCEED, FAIL,
-H5EA__cache_hdr_dest(H5F_t *f, H5EA_hdr_t *hdr))
+    /* Local variables */
+    const H5EA_hdr_t *hdr = (const H5EA_hdr_t *)_udata; /* User data for callback */
+    H5EA_iblock_t iblock;           /* Fake index block for computing size */
 
     /* Check arguments */
-    HDassert(f);
     HDassert(hdr);
+    HDassert(image_len);
 
-    /* Verify that header is clean */
-    HDassert(hdr->cache_info.is_dirty == FALSE);
-
-    /* If we're going to free the space on disk, the address must be valid */
-    HDassert(!hdr->cache_info.free_file_space_on_destroy || H5F_addr_defined(hdr->cache_info.addr));
-
-    /* Check for freeing file space for extensible array header */
-    if(hdr->cache_info.free_file_space_on_destroy) {
-        /* Sanity check address */
-        HDassert(H5F_addr_eq(hdr->addr, hdr->cache_info.addr));
-
-        /* Release the space on disk */
-        /* (XXX: Nasty usage of internal DXPL value! -QAK) */
-        if(H5MF_xfree(f, H5FD_MEM_EARRAY_HDR, H5AC_dxpl_id, hdr->cache_info.addr, (hsize_t)hdr->size) < 0)
-            H5E_THROW(H5E_CANTFREE, "unable to free extensible array header")
-    } /* end if */
+    /* Set up fake index block for computing size on disk */
+    HDmemset(&iblock, 0, sizeof(iblock));
+    iblock.hdr = (H5EA_hdr_t *)hdr;     /* Casting away 'const' OK - QAK */
+    iblock.nsblks = H5EA_SBLK_FIRST_IDX(hdr->cparam.sup_blk_min_data_ptrs);
+    iblock.ndblk_addrs = 2 * ((size_t)hdr->cparam.sup_blk_min_data_ptrs - 1);
+    iblock.nsblk_addrs = hdr->nsblks - iblock.nsblks;
 
-    /* Release the extensible array header */
-    if(H5EA__hdr_dest(hdr) < 0)
-        H5E_THROW(H5E_CANTFREE, "can't free extensible array header")
-
-CATCH
+    /* Set the image length size */
+    *image_len = (size_t)H5EA_IBLOCK_SIZE(&iblock);
 
-END_FUNC(STATIC)   /* end H5EA__cache_hdr_dest() */
+END_FUNC(STATIC)   /* end H5EA__cache_iblock_get_load_size() */
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5EA__cache_iblock_load
+ * Function:	H5EA__cache_iblock_deserialize
  *
- * Purpose:	Loads an extensible array index block from the disk.
+ * Purpose:	Loads a data structure from the disk.
  *
- * Return:	Success:	Pointer to a new extensible array index block
+ * Return:	Success:	Pointer to a new B-tree.
  *		Failure:	NULL
  *
  * Programmer:	Quincey Koziol
- *		koziol@hdfgroup.org
- *		Sep  9 2008
+ *              koziol@hdfgroup.org
+ *              July 17, 2013
  *
  *-------------------------------------------------------------------------
  */
 BEGIN_FUNC(STATIC, ERR,
-H5EA_iblock_t *, NULL, NULL,
-H5EA__cache_iblock_load(H5F_t *f, hid_t dxpl_id, haddr_t addr, void *_udata))
+void *, NULL, NULL,
+H5EA__cache_iblock_deserialize(const void *_image, size_t len,
+    void *_udata, hbool_t H5_ATTR_UNUSED *dirty))
 
     /* Local variables */
-    H5EA_hdr_t    *hdr = (H5EA_hdr_t *)_udata;   /* Shared extensible array information */
     H5EA_iblock_t	*iblock = NULL; /* Index block info */
-    size_t		size;           /* Index block size */
-    H5WB_t              *wb = NULL;     /* Wrapped buffer for index block data */
-    uint8_t             iblock_buf[H5EA_IBLOCK_BUF_SIZE]; /* Buffer for index block */
-    uint8_t		*buf;           /* Pointer to index block buffer */
-    const uint8_t	*p;             /* Pointer into raw data buffer */
+    H5EA_hdr_t *hdr = (H5EA_hdr_t *)_udata;     /* User data for callback */
+    const uint8_t	*image = (const uint8_t *)_image;       /* Pointer into raw data buffer */
     uint32_t            stored_chksum;  /* Stored metadata checksum value */
     uint32_t            computed_chksum; /* Computed metadata checksum value */
     haddr_t             arr_addr;       /* Address of array header in the file */
     size_t              u;              /* Local index variable */
 
-    /* Sanity check */
-    HDassert(f);
-    HDassert(H5F_addr_defined(addr));
+    /* Check arguments */
+    HDassert(image);
     HDassert(hdr);
 
     /* Allocate the extensible array index block */
@@ -589,41 +598,23 @@ H5EA__cache_iblock_load(H5F_t *f, hid_t dxpl_id, haddr_t addr, void *_udata))
 	H5E_THROW(H5E_CANTALLOC, "memory allocation failed for extensible array index block")
 
     /* Set the extensible array index block's address */
-    iblock->addr = addr;
-
-    /* Wrap the local buffer for serialized info */
-    if(NULL == (wb = H5WB_wrap(iblock_buf, sizeof(iblock_buf))))
-	H5E_THROW(H5E_CANTINIT, "can't wrap buffer")
-
-    /* Compute the size of the extensible array index block on disk */
-    size = H5EA_IBLOCK_SIZE(iblock);
-
-    /* Get a pointer to a buffer that's large enough for serialized info */
-    if(NULL == (buf = (uint8_t *)H5WB_actual(wb, size)))
-	H5E_THROW(H5E_CANTGET, "can't get actual buffer")
-
-    /* Read index block from disk */
-    if(H5F_block_read(f, H5FD_MEM_EARRAY_IBLOCK, addr, size, dxpl_id, buf) < 0)
-	H5E_THROW(H5E_READERROR, "can't read extensible array index block")
-
-    /* Get temporary pointer to serialized header */
-    p = buf;
+    iblock->addr = hdr->idx_blk_addr;
 
     /* Magic number */
-    if(HDmemcmp(p, H5EA_IBLOCK_MAGIC, (size_t)H5_SIZEOF_MAGIC))
+    if(HDmemcmp(image, H5EA_IBLOCK_MAGIC, (size_t)H5_SIZEOF_MAGIC))
 	H5E_THROW(H5E_BADVALUE, "wrong extensible array index block signature")
-    p += H5_SIZEOF_MAGIC;
+    image += H5_SIZEOF_MAGIC;
 
     /* Version */
-    if(*p++ != H5EA_IBLOCK_VERSION)
+    if(*image++ != H5EA_IBLOCK_VERSION)
 	H5E_THROW(H5E_VERSION, "wrong extensible array index block version")
 
     /* Extensible array type */
-    if(*p++ != (uint8_t)hdr->cparam.cls->id)
+    if(*image++ != (uint8_t)hdr->cparam.cls->id)
 	H5E_THROW(H5E_BADTYPE, "incorrect extensible array class")
 
     /* Address of header for array that owns this block (just for file integrity checks) */
-    H5F_addr_decode(f, &p, &arr_addr);
+    H5F_addr_decode(hdr->f, &image, &arr_addr);
     if(H5F_addr_ne(arr_addr, hdr->addr))
 	H5E_THROW(H5E_BADVALUE, "wrong extensible array header address")
 
@@ -632,40 +623,40 @@ H5EA__cache_iblock_load(H5F_t *f, hid_t dxpl_id, haddr_t addr, void *_udata))
     /* Decode elements in index block */
     if(hdr->cparam.idx_blk_elmts > 0) {
         /* Convert from raw elements on disk into native elements in memory */
-        if((hdr->cparam.cls->decode)(p, iblock->elmts, (size_t)hdr->cparam.idx_blk_elmts, hdr->cb_ctx) < 0)
+        if((hdr->cparam.cls->decode)(image, iblock->elmts, (size_t)hdr->cparam.idx_blk_elmts, hdr->cb_ctx) < 0)
             H5E_THROW(H5E_CANTDECODE, "can't decode extensible array index elements")
-        p += (hdr->cparam.idx_blk_elmts * hdr->cparam.raw_elmt_size);
+        image += (hdr->cparam.idx_blk_elmts * hdr->cparam.raw_elmt_size);
     } /* end if */
 
     /* Decode data block addresses in index block */
     if(iblock->ndblk_addrs > 0) {
         /* Decode addresses of data blocks in index block */
         for(u = 0; u < iblock->ndblk_addrs; u++)
-            H5F_addr_decode(f, &p, &iblock->dblk_addrs[u]);
+            H5F_addr_decode(hdr->f, &image, &iblock->dblk_addrs[u]);
     } /* end if */
 
     /* Decode super block addresses in index block */
     if(iblock->nsblk_addrs > 0) {
         /* Decode addresses of super blocks in index block */
         for(u = 0; u < iblock->nsblk_addrs; u++)
-            H5F_addr_decode(f, &p, &iblock->sblk_addrs[u]);
+            H5F_addr_decode(hdr->f, &image, &iblock->sblk_addrs[u]);
     } /* end if */
 
     /* Sanity check */
     /* (allow for checksum not decoded yet) */
-    HDassert((size_t)(p - buf) == (size - H5EA_SIZEOF_CHKSUM));
+    HDassert((size_t)(image - (const uint8_t *)_image) == (len - H5EA_SIZEOF_CHKSUM));
 
     /* Save the index block's size */
-    iblock->size = size;
+    iblock->size = len;
 
     /* Compute checksum on index block */
-    computed_chksum = H5_checksum_metadata(buf, (size_t)(p - buf), 0);
+    computed_chksum = H5_checksum_metadata((const uint8_t *)_image, (size_t)(image - (const uint8_t *)_image), 0);
 
     /* Metadata checksum */
-    UINT32DECODE(p, stored_chksum);
+    UINT32DECODE(image, stored_chksum);
 
     /* Sanity check */
-    HDassert((size_t)(p - buf) == iblock->size);
+    HDassert((size_t)(image - (const uint8_t *)_image) == iblock->size);
 
     /* Verify checksum */
     if(stored_chksum != computed_chksum)
@@ -677,161 +668,128 @@ H5EA__cache_iblock_load(H5F_t *f, hid_t dxpl_id, haddr_t addr, void *_udata))
 CATCH
 
     /* Release resources */
-    if(wb && H5WB_unwrap(wb) < 0)
-	H5E_THROW(H5E_CLOSEERROR, "can't close wrapped buffer")
     if(!ret_value)
         if(iblock && H5EA__iblock_dest(iblock) < 0)
             H5E_THROW(H5E_CANTFREE, "unable to destroy extensible array index block")
 
-END_FUNC(STATIC)   /* end H5EA__cache_iblock_load() */
+END_FUNC(STATIC)   /* end H5EA__cache_iblock_deserialize() */
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5EA__cache_iblock_flush
+ * Function:    H5EA__cache_iblock_image_len
+ *
+ * Purpose:     Compute the size of the data structure on disk.
+ *
+ * Return:      Non-negative on success/Negative on failure
  *
- * Purpose:	Flushes a dirty extensible array index block to disk.
+ * Programmer:  Quincey Koziol
+ *              koziol@hdfgroup.org
+ *              July 17, 2013
+ *
+ *-------------------------------------------------------------------------
+ */
+BEGIN_FUNC(STATIC, NOERR,
+herr_t, SUCCEED, -,
+H5EA__cache_iblock_image_len(const void *_thing, size_t *image_len,
+    hbool_t H5_ATTR_UNUSED *compressed_ptr, size_t H5_ATTR_UNUSED *compressed_image_len_ptr))
+
+    /* Local variables */
+    const H5EA_iblock_t *iblock = (const H5EA_iblock_t *)_thing;      /* Pointer to the object */
+
+    /* Check arguments */
+    HDassert(iblock);
+    HDassert(image_len);
+
+    /* Set the image length size */
+    *image_len = iblock->size;
+
+END_FUNC(STATIC)   /* end H5EA__cache_iblock_image_len() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:	H5EA__cache_iblock_serialize
+ *
+ * Purpose:	Flushes a dirty object to disk.
  *
  * Return:	Non-negative on success/Negative on failure
  *
  * Programmer:	Quincey Koziol
- *		koziol@hdfgroup.org
- *		Sep  9 2008
+ *              koziol@hdfgroup.org
+ *              July 17, 2013
  *
  *-------------------------------------------------------------------------
  */
 BEGIN_FUNC(STATIC, ERR,
 herr_t, SUCCEED, FAIL,
-H5EA__cache_iblock_flush(H5F_t *f, hid_t dxpl_id, hbool_t destroy, haddr_t addr,
-    H5EA_iblock_t *iblock, unsigned H5_ATTR_UNUSED * flags_ptr))
+H5EA__cache_iblock_serialize(const H5F_t *f, void *_image, size_t H5_ATTR_UNUSED len,
+    void *_thing))
 
     /* Local variables */
-    H5WB_t *wb = NULL;                  /* Wrapped buffer for serializing data */
-    uint8_t ser_buf[H5EA_IBLOCK_BUF_SIZE]; /* Serialization buffer */
+    H5EA_iblock_t *iblock = (H5EA_iblock_t *)_thing;      /* Pointer to the object to serialize */
+    uint8_t *image = (uint8_t *)_image;         /* Pointer into raw data buffer */
+    uint32_t metadata_chksum;   /* Computed metadata checksum value */
 
-    /* Sanity check */
+    /* check arguments */
     HDassert(f);
-    HDassert(H5F_addr_defined(addr));
+    HDassert(image);
     HDassert(iblock);
     HDassert(iblock->hdr);
 
-    if(iblock->cache_info.is_dirty) {
-        uint8_t	*buf;           /* Temporary raw data buffer */
-        uint8_t *p;             /* Pointer into raw data buffer */
-        size_t	size;           /* Index block size on disk */
-        uint32_t metadata_chksum; /* Computed metadata checksum value */
-
-        /* Wrap the local buffer for serialized info */
-        if(NULL == (wb = H5WB_wrap(ser_buf, sizeof(ser_buf))))
-            H5E_THROW(H5E_CANTINIT, "can't wrap buffer")
-
-        /* Compute the size of the index block on disk */
-        size = iblock->size;
-
-        /* Get a pointer to a buffer that's large enough for serialized info */
-        if(NULL == (buf = (uint8_t *)H5WB_actual(wb, size)))
-            H5E_THROW(H5E_CANTGET, "can't get actual buffer")
-
-        /* Get temporary pointer to serialized info */
-        p = buf;
+    /* Get temporary pointer to serialized info */
 
-        /* Magic number */
-        HDmemcpy(p, H5EA_IBLOCK_MAGIC, (size_t)H5_SIZEOF_MAGIC);
-        p += H5_SIZEOF_MAGIC;
-
-        /* Version # */
-        *p++ = H5EA_IBLOCK_VERSION;
-
-        /* Extensible array type */
-        *p++ = iblock->hdr->cparam.cls->id;
-
-        /* Address of array header for array which owns this block */
-        H5F_addr_encode(f, &p, iblock->hdr->addr);
-
-        /* Internal information */
-
-        /* Encode elements in index block */
-        if(iblock->hdr->cparam.idx_blk_elmts > 0) {
-            /* Convert from native elements in memory into raw elements on disk */
-            if((iblock->hdr->cparam.cls->encode)(p, iblock->elmts, (size_t)iblock->hdr->cparam.idx_blk_elmts, iblock->hdr->cb_ctx) < 0)
-                H5E_THROW(H5E_CANTENCODE, "can't encode extensible array index elements")
-            p += (iblock->hdr->cparam.idx_blk_elmts * iblock->hdr->cparam.raw_elmt_size);
-        } /* end if */
-
-        /* Encode data block addresses in index block */
-        if(iblock->ndblk_addrs > 0) {
-            size_t u;               /* Local index variable */
+    /* Magic number */
+    HDmemcpy(image, H5EA_IBLOCK_MAGIC, (size_t)H5_SIZEOF_MAGIC);
+    image += H5_SIZEOF_MAGIC;
 
-            /* Encode addresses of data blocks in index block */
-            for(u = 0; u < iblock->ndblk_addrs; u++)
-                H5F_addr_encode(f, &p, iblock->dblk_addrs[u]);
-        } /* end if */
+    /* Version # */
+    *image++ = H5EA_IBLOCK_VERSION;
 
-        /* Encode data block addresses in index block */
-        if(iblock->nsblk_addrs > 0) {
-            size_t u;               /* Local index variable */
+    /* Extensible array type */
+    *image++ = iblock->hdr->cparam.cls->id;
 
-            /* Encode addresses of super blocks in index block */
-            for(u = 0; u < iblock->nsblk_addrs; u++)
-                H5F_addr_encode(f, &p, iblock->sblk_addrs[u]);
-        } /* end if */
+    /* Address of array header for array which owns this block */
+    H5F_addr_encode(f, &image, iblock->hdr->addr);
 
-        /* Compute metadata checksum */
-        metadata_chksum = H5_checksum_metadata(buf, (size_t)(p - buf), 0);
+    /* Internal information */
 
-        /* Metadata checksum */
-        UINT32ENCODE(p, metadata_chksum);
+    /* Encode elements in index block */
+    if(iblock->hdr->cparam.idx_blk_elmts > 0) {
+        /* Convert from native elements in memory into raw elements on disk */
+        if((iblock->hdr->cparam.cls->encode)(image, iblock->elmts, (size_t)iblock->hdr->cparam.idx_blk_elmts, iblock->hdr->cb_ctx) < 0)
+            H5E_THROW(H5E_CANTENCODE, "can't encode extensible array index elements")
+        image += (iblock->hdr->cparam.idx_blk_elmts * iblock->hdr->cparam.raw_elmt_size);
+    } /* end if */
 
-	/* Write the index block */
-        HDassert((size_t)(p - buf) == size);
-	if(H5F_block_write(f, H5FD_MEM_EARRAY_IBLOCK, addr, size, dxpl_id, buf) < 0)
-            H5E_THROW(H5E_WRITEERROR, "unable to save extensible array index block to disk")
+    /* Encode data block addresses in index block */
+    if(iblock->ndblk_addrs > 0) {
+        size_t u;               /* Local index variable */
 
-	iblock->cache_info.is_dirty = FALSE;
+        /* Encode addresses of data blocks in index block */
+        for(u = 0; u < iblock->ndblk_addrs; u++)
+            H5F_addr_encode(f, &image, iblock->dblk_addrs[u]);
     } /* end if */
 
-    if(destroy)
-        if(H5EA__cache_iblock_dest(f, iblock) < 0)
-            H5E_THROW(H5E_CANTFREE, "unable to destroy extensible array index block")
-
-CATCH
+    /* Encode data block addresses in index block */
+    if(iblock->nsblk_addrs > 0) {
+        size_t u;               /* Local index variable */
 
-    /* Release resources */
-    if(wb && H5WB_unwrap(wb) < 0)
-	H5E_THROW(H5E_CLOSEERROR, "can't close wrapped buffer")
+        /* Encode addresses of super blocks in index block */
+        for(u = 0; u < iblock->nsblk_addrs; u++)
+            H5F_addr_encode(f, &image, iblock->sblk_addrs[u]);
+    } /* end if */
 
-END_FUNC(STATIC)   /* end H5EA__cache_iblock_flush() */
+    /* Compute metadata checksum */
+    metadata_chksum = H5_checksum_metadata(_image, (size_t)(image - (uint8_t *)_image), 0);
 
-
-/*-------------------------------------------------------------------------
- * Function:	H5EA__cache_iblock_clear
- *
- * Purpose:	Mark a extensible array index block in memory as non-dirty.
- *
- * Return:	Non-negative on success/Negative on failure
- *
- * Programmer:	Quincey Koziol
- *		koziol@hdfgroup.org
- *		Sept 9 2008
- *
- *-------------------------------------------------------------------------
- */
-BEGIN_FUNC(STATIC, ERR,
-herr_t, SUCCEED, FAIL,
-H5EA__cache_iblock_clear(H5F_t *f, H5EA_iblock_t *iblock, hbool_t destroy))
+    /* Metadata checksum */
+    UINT32ENCODE(image, metadata_chksum);
 
     /* Sanity check */
-    HDassert(iblock);
-
-    /* Reset the dirty flag */
-    iblock->cache_info.is_dirty = FALSE;
-
-    if(destroy)
-        if(H5EA__cache_iblock_dest(f, iblock) < 0)
-            H5E_THROW(H5E_CANTFREE, "unable to destroy extensible array index block")
+    HDassert((size_t)(image - (uint8_t *)_image) <= len);
 
 CATCH
 
-END_FUNC(STATIC)   /* end H5EA__cache_iblock_clear() */
+END_FUNC(STATIC)   /* end H5EA__cache_iblock_serialize() */
 
 
 /*-------------------------------------------------------------------------
@@ -843,13 +801,16 @@ END_FUNC(STATIC)   /* end H5EA__cache_iblock_clear() */
  *
  * Programmer:	Quincey Koziol
  *		koziol@hdfgroup.org
- *		Mar 31 2009
+ *              July 17, 2013
  *
  *-------------------------------------------------------------------------
  */
 BEGIN_FUNC(STATIC, ERR,
 herr_t, SUCCEED, FAIL,
-H5EA__cache_iblock_notify(H5AC_notify_action_t action, H5EA_iblock_t *iblock))
+H5EA__cache_iblock_notify(H5AC_notify_action_t action, void *_thing))
+
+    /* Local variables */
+    H5EA_iblock_t *iblock = (H5EA_iblock_t *)_thing;      /* Pointer to the object */
 
     /* Sanity check */
     HDassert(iblock);
@@ -857,11 +818,16 @@ H5EA__cache_iblock_notify(H5AC_notify_action_t action, H5EA_iblock_t *iblock))
     /* Determine which action to take */
     switch(action) {
         case H5AC_NOTIFY_ACTION_AFTER_INSERT:
+        case H5AC_NOTIFY_ACTION_AFTER_LOAD:
             /* Create flush dependency on extensible array header */
             if(H5EA__create_flush_depend((H5AC_info_t *)iblock->hdr, (H5AC_info_t *)iblock) < 0)
                 H5E_THROW(H5E_CANTDEPEND, "unable to create flush dependency between index block and header, address = %llu", (unsigned long long)iblock->addr)
             break;
 
+	case H5AC_NOTIFY_ACTION_AFTER_FLUSH:
+	    /* do nothing */
+	    break;
+
         case H5AC_NOTIFY_ACTION_BEFORE_EVICT:
             /* Destroy flush dependency on extensible array header */
             if(H5EA__destroy_flush_depend((H5AC_info_t *)iblock->hdr, (H5AC_info_t *)iblock) < 0)
@@ -878,165 +844,155 @@ END_FUNC(STATIC)   /* end H5EA__cache_iblock_notify() */
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5EA__cache_iblock_size
+ * Function:	H5EA__cache_iblock_free_icr
  *
- * Purpose:	Compute the size in bytes of a extensible array index block
- *		on disk, and return it in *size_ptr.  On failure,
- *		the value of *size_ptr is undefined.
+ * Purpose:	Destroy/release an "in core representation" of a data
+ *              structure
  *
  * Return:	Non-negative on success/Negative on failure
  *
  * Programmer:	Quincey Koziol
- *		koziol@hdfgroup.org
- *		Sept 9 2008
+ *              koziol@hdfgroup.org
+ *              July 17, 2013
  *
  *-------------------------------------------------------------------------
  */
-/* ARGSUSED */
-BEGIN_FUNC(STATIC, NOERR,
-herr_t, SUCCEED, -,
-H5EA__cache_iblock_size(const H5F_t H5_ATTR_UNUSED *f, const H5EA_iblock_t *iblock,
-    size_t *size_ptr))
+BEGIN_FUNC(STATIC, ERR,
+herr_t, SUCCEED, FAIL,
+H5EA__cache_iblock_free_icr(void *thing))
 
-    /* Sanity check */
-    HDassert(f);
-    HDassert(iblock);
-    HDassert(size_ptr);
+    /* Check arguments */
+    HDassert(thing);
+
+    /* Release the extensible array index block */
+    if(H5EA__iblock_dest((H5EA_iblock_t *)thing) < 0)
+        H5E_THROW(H5E_CANTFREE, "can't free extensible array index block")
 
-    /* Set size value */
-    *size_ptr = iblock->size;
+CATCH
 
-END_FUNC(STATIC)   /* end H5EA__cache_iblock_size() */
+END_FUNC(STATIC)   /* end H5EA__cache_iblock_free_icr() */
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5EA__cache_iblock_dest
+ * Function:    H5EA__cache_sblock_get_load_size
  *
- * Purpose:	Destroys an extensible array index block in memory.
+ * Purpose:     Compute the size of the data structure on disk.
  *
- * Return:	Non-negative on success/Negative on failure
+ * Return:      Non-negative on success/Negative on failure
  *
- * Programmer:	Quincey Koziol
- *		koziol@hdfgroup.org
- *		Sep  9 2008
+ * Programmer:  Quincey Koziol
+ *              koziol@hdfgroup.org
+ *              July 17, 2013
  *
  *-------------------------------------------------------------------------
  */
-BEGIN_FUNC(STATIC, ERR,
-herr_t, SUCCEED, FAIL,
-H5EA__cache_iblock_dest(H5F_t *f, H5EA_iblock_t *iblock))
-
-    /* Sanity check */
-    HDassert(f);
-    HDassert(iblock);
-
-    /* Verify that index block is clean */
-    HDassert(iblock->cache_info.is_dirty == FALSE);
-
-    /* If we're going to free the space on disk, the address must be valid */
-    HDassert(!iblock->cache_info.free_file_space_on_destroy || H5F_addr_defined(iblock->cache_info.addr));
+BEGIN_FUNC(STATIC, NOERR,
+herr_t, SUCCEED, -,
+H5EA__cache_sblock_get_load_size(const void *_udata, size_t *image_len))
 
-    /* Check for freeing file space for extensible array index block */
-    if(iblock->cache_info.free_file_space_on_destroy) {
-        /* Sanity check address */
-        HDassert(H5F_addr_eq(iblock->addr, iblock->cache_info.addr));
+    /* Local variables */
+    const H5EA_sblock_cache_ud_t *udata = (const H5EA_sblock_cache_ud_t *)_udata;      /* User data */
+    H5EA_sblock_t sblock;           /* Fake super block for computing size */
 
-        /* Release the space on disk */
-        /* (XXX: Nasty usage of internal DXPL value! -QAK) */
-        if(H5MF_xfree(f, H5FD_MEM_EARRAY_IBLOCK, H5AC_dxpl_id, iblock->cache_info.addr, (hsize_t)iblock->size) < 0)
-            H5E_THROW(H5E_CANTFREE, "unable to free extensible array index block")
+    /* Check arguments */
+    HDassert(udata);
+    HDassert(udata->hdr);
+    HDassert(udata->parent);
+    HDassert(udata->sblk_idx > 0);
+    HDassert(H5F_addr_defined(udata->sblk_addr));
+    HDassert(image_len);
+
+    /* Set up fake super block for computing size on disk */
+    /* (Note: extracted from H5EA__sblock_alloc) */
+    HDmemset(&sblock, 0, sizeof(sblock));
+    sblock.hdr = udata->hdr;
+    sblock.ndblks = udata->hdr->sblk_info[udata->sblk_idx].ndblks;
+    sblock.dblk_nelmts = udata->hdr->sblk_info[udata->sblk_idx].dblk_nelmts;
+
+    /* Check if # of elements in data blocks requires paging */
+    if(sblock.dblk_nelmts > udata->hdr->dblk_page_nelmts) {
+        /* Compute # of pages in each data block from this super block */
+        sblock.dblk_npages = sblock.dblk_nelmts / udata->hdr->dblk_page_nelmts;
+
+        /* Sanity check that we have at least 2 pages in data block */
+        HDassert(sblock.dblk_npages > 1);
+
+        /* Sanity check for integer truncation */
+        HDassert((sblock.dblk_npages * udata->hdr->dblk_page_nelmts) == sblock.dblk_nelmts);
+
+        /* Compute size of buffer for each data block's 'page init' bitmask */
+        sblock.dblk_page_init_size = ((sblock.dblk_npages) + 7) / 8;
+        HDassert(sblock.dblk_page_init_size > 0);
     } /* end if */
 
-    /* Release the index block */
-    if(H5EA__iblock_dest(iblock) < 0)
-        H5E_THROW(H5E_CANTFREE, "can't free extensible array index block")
-
-CATCH
+    /* Set the image length size */
+    *image_len = (size_t)H5EA_SBLOCK_SIZE(&sblock);
 
-END_FUNC(STATIC)   /* end H5EA__cache_iblock_dest() */
+END_FUNC(STATIC)   /* end H5EA__cache_sblock_get_load_size() */
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5EA__cache_sblock_load
+ * Function:	H5EA__cache_sblock_deserialize
  *
- * Purpose:	Loads an extensible array super block from the disk.
+ * Purpose:	Loads a data structure from the disk.
  *
- * Return:	Success:	Pointer to a new extensible array super block
+ * Return:	Success:	Pointer to a new B-tree.
  *		Failure:	NULL
  *
  * Programmer:	Quincey Koziol
- *		koziol@hdfgroup.org
- *		Sep 30 2008
+ *              koziol@hdfgroup.org
+ *              July 17, 2013
  *
  *-------------------------------------------------------------------------
  */
 BEGIN_FUNC(STATIC, ERR,
-H5EA_sblock_t *, NULL, NULL,
-H5EA__cache_sblock_load(H5F_t *f, hid_t dxpl_id, haddr_t addr, void *_udata))
+void *, NULL, NULL,
+H5EA__cache_sblock_deserialize(const void *_image, size_t len,
+    void *_udata, hbool_t H5_ATTR_UNUSED *dirty))
 
     /* Local variables */
     H5EA_sblock_t	*sblock = NULL; /* Super block info */
-    H5EA_sblock_cache_ud_t *udata = (H5EA_sblock_cache_ud_t *)_udata;      /* User data for loading super block */
-    size_t		size;           /* Super block size */
-    H5WB_t              *wb = NULL;     /* Wrapped buffer for super block data */
-    uint8_t             sblock_buf[H5EA_IBLOCK_BUF_SIZE]; /* Buffer for super block */
-    uint8_t		*buf;           /* Pointer to super block buffer */
-    const uint8_t	*p;             /* Pointer into raw data buffer */
+    H5EA_sblock_cache_ud_t *udata = (H5EA_sblock_cache_ud_t *)_udata;      /* User data */
+    const uint8_t	*image = (const uint8_t *)_image;       /* Pointer into raw data buffer */
     uint32_t            stored_chksum;  /* Stored metadata checksum value */
     uint32_t            computed_chksum; /* Computed metadata checksum value */
     haddr_t             arr_addr;       /* Address of array header in the file */
     size_t              u;              /* Local index variable */
 
     /* Sanity check */
-    HDassert(f);
-    HDassert(H5F_addr_defined(addr));
-    HDassert(udata && udata->hdr && udata->parent && udata->sblk_idx > 0);
+    HDassert(udata);
+    HDassert(udata->hdr);
+    HDassert(udata->parent);
+    HDassert(udata->sblk_idx > 0);
+    HDassert(H5F_addr_defined(udata->sblk_addr));
 
     /* Allocate the extensible array super block */
     if(NULL == (sblock = H5EA__sblock_alloc(udata->hdr, udata->parent, udata->sblk_idx)))
 	H5E_THROW(H5E_CANTALLOC, "memory allocation failed for extensible array super block")
 
     /* Set the extensible array super block's address */
-    sblock->addr = addr;
-
-    /* Wrap the local buffer for serialized info */
-    if(NULL == (wb = H5WB_wrap(sblock_buf, sizeof(sblock_buf))))
-	H5E_THROW(H5E_CANTINIT, "can't wrap buffer")
-
-    /* Compute the size of the extensible array super block on disk */
-    size = H5EA_SBLOCK_SIZE(sblock);
-
-    /* Get a pointer to a buffer that's large enough for serialized info */
-    if(NULL == (buf = (uint8_t *)H5WB_actual(wb, size)))
-	H5E_THROW(H5E_CANTGET, "can't get actual buffer")
-
-    /* Read super block from disk */
-    if(H5F_block_read(f, H5FD_MEM_EARRAY_SBLOCK, addr, size, dxpl_id, buf) < 0)
-	H5E_THROW(H5E_READERROR, "can't read extensible array super block")
-
-    /* Get temporary pointer to serialized header */
-    p = buf;
+    sblock->addr = udata->sblk_addr;
 
     /* Magic number */
-    if(HDmemcmp(p, H5EA_SBLOCK_MAGIC, (size_t)H5_SIZEOF_MAGIC))
+    if(HDmemcmp(image, H5EA_SBLOCK_MAGIC, (size_t)H5_SIZEOF_MAGIC))
 	H5E_THROW(H5E_BADVALUE, "wrong extensible array super block signature")
-    p += H5_SIZEOF_MAGIC;
+    image += H5_SIZEOF_MAGIC;
 
     /* Version */
-    if(*p++ != H5EA_SBLOCK_VERSION)
+    if(*image++ != H5EA_SBLOCK_VERSION)
 	H5E_THROW(H5E_VERSION, "wrong extensible array super block version")
 
     /* Extensible array type */
-    if(*p++ != (uint8_t)udata->hdr->cparam.cls->id)
+    if(*image++ != (uint8_t)udata->hdr->cparam.cls->id)
 	H5E_THROW(H5E_BADTYPE, "incorrect extensible array class")
 
     /* Address of header for array that owns this block (just for file integrity checks) */
-    H5F_addr_decode(f, &p, &arr_addr);
+    H5F_addr_decode(udata->hdr->f, &image, &arr_addr);
     if(H5F_addr_ne(arr_addr, udata->hdr->addr))
 	H5E_THROW(H5E_BADVALUE, "wrong extensible array header address")
 
     /* Offset of block within the array's address space */
-    UINT64DECODE_VAR(p, sblock->block_off, udata->hdr->arr_off_size);
+    UINT64DECODE_VAR(image, sblock->block_off, udata->hdr->arr_off_size);
 
     /* Internal information */
 
@@ -1045,29 +1001,29 @@ H5EA__cache_sblock_load(H5F_t *f, hid_t dxpl_id, haddr_t addr, void *_udata))
         size_t tot_page_init_size = sblock->ndblks * sblock->dblk_page_init_size;        /* Compute total size of 'page init' buffer */
 
         /* Retrieve the 'page init' bitmasks */
-        HDmemcpy(sblock->page_init, p, tot_page_init_size);
-        p += tot_page_init_size;
+        HDmemcpy(sblock->page_init, image, tot_page_init_size);
+        image += tot_page_init_size;
     } /* end if */
 
     /* Decode data block addresses */
     for(u = 0; u < sblock->ndblks; u++)
-        H5F_addr_decode(f, &p, &sblock->dblk_addrs[u]);
+        H5F_addr_decode(udata->hdr->f, &image, &sblock->dblk_addrs[u]);
 
     /* Sanity check */
     /* (allow for checksum not decoded yet) */
-    HDassert((size_t)(p - buf) == (size - H5EA_SIZEOF_CHKSUM));
+    HDassert((size_t)(image - (const uint8_t *)_image) == (len - H5EA_SIZEOF_CHKSUM));
 
     /* Save the super block's size */
-    sblock->size = size;
+    sblock->size = len;
 
     /* Compute checksum on super block */
-    computed_chksum = H5_checksum_metadata(buf, (size_t)(p - buf), 0);
+    computed_chksum = H5_checksum_metadata(_image, (size_t)(image - (const uint8_t *)_image), 0);
 
     /* Metadata checksum */
-    UINT32DECODE(p, stored_chksum);
+    UINT32DECODE(image, stored_chksum);
 
     /* Sanity check */
-    HDassert((size_t)(p - buf) == sblock->size);
+    HDassert((size_t)(image - (const uint8_t *)_image) == sblock->size);
 
     /* Verify checksum */
     if(stored_chksum != computed_chksum)
@@ -1079,183 +1035,115 @@ H5EA__cache_sblock_load(H5F_t *f, hid_t dxpl_id, haddr_t addr, void *_udata))
 CATCH
 
     /* Release resources */
-    if(wb && H5WB_unwrap(wb) < 0)
-	H5E_THROW(H5E_CLOSEERROR, "can't close wrapped buffer")
     if(!ret_value)
         if(sblock && H5EA__sblock_dest(sblock) < 0)
             H5E_THROW(H5E_CANTFREE, "unable to destroy extensible array super block")
 
-END_FUNC(STATIC)   /* end H5EA__cache_sblock_load() */
+END_FUNC(STATIC)   /* end H5EA__cache_sblock_deserialize() */
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5EA__cache_sblock_flush
+ * Function:    H5EA__cache_sblock_image_len
  *
- * Purpose:	Flushes a dirty extensible array super block to disk.
+ * Purpose:     Compute the size of the data structure on disk.
  *
- * Return:	Non-negative on success/Negative on failure
+ * Return:      Non-negative on success/Negative on failure
  *
- * Programmer:	Quincey Koziol
- *		koziol@hdfgroup.org
- *		Sep 30 2008
+ * Programmer:  Quincey Koziol
+ *              koziol@hdfgroup.org
+ *              July 17, 2013
  *
  *-------------------------------------------------------------------------
  */
-BEGIN_FUNC(STATIC, ERR,
-herr_t, SUCCEED, FAIL,
-H5EA__cache_sblock_flush(H5F_t *f, hid_t dxpl_id, hbool_t destroy, haddr_t addr,
-    H5EA_sblock_t *sblock, unsigned H5_ATTR_UNUSED * flags_ptr))
+BEGIN_FUNC(STATIC, NOERR,
+herr_t, SUCCEED, -,
+H5EA__cache_sblock_image_len(const void *_thing, size_t *image_len,
+    hbool_t H5_ATTR_UNUSED *compressed_ptr, size_t H5_ATTR_UNUSED *compressed_image_len_ptr))
 
     /* Local variables */
-    H5WB_t *wb = NULL;                  /* Wrapped buffer for serializing data */
-    uint8_t ser_buf[H5EA_SBLOCK_BUF_SIZE]; /* Serialization buffer */
+    const H5EA_sblock_t *sblock = (const H5EA_sblock_t *)_thing;      /* Pointer to the object */
 
-    /* Sanity check */
-    HDassert(f);
-    HDassert(H5F_addr_defined(addr));
+    /* Check arguments */
     HDassert(sblock);
-    HDassert(sblock->hdr);
+    HDassert(image_len);
 
-    if(sblock->cache_info.is_dirty) {
-        uint8_t	*buf;           /* Temporary raw data buffer */
-        uint8_t *p;             /* Pointer into raw data buffer */
-        size_t	size;           /* Index block size on disk */
-        uint32_t metadata_chksum; /* Computed metadata checksum value */
-        size_t u;               /* Local index variable */
+    /* Set the image length size */
+    *image_len = sblock->size;
 
-        /* Wrap the local buffer for serialized info */
-        if(NULL == (wb = H5WB_wrap(ser_buf, sizeof(ser_buf))))
-            H5E_THROW(H5E_CANTINIT, "can't wrap buffer")
-
-        /* Compute the size of the super block on disk */
-        size = sblock->size;
-
-        /* Get a pointer to a buffer that's large enough for serialized info */
-        if(NULL == (buf = (uint8_t *)H5WB_actual(wb, size)))
-            H5E_THROW(H5E_CANTGET, "can't get actual buffer")
-
-        /* Get temporary pointer to serialized info */
-        p = buf;
-
-        /* Magic number */
-        HDmemcpy(p, H5EA_SBLOCK_MAGIC, (size_t)H5_SIZEOF_MAGIC);
-        p += H5_SIZEOF_MAGIC;
-
-        /* Version # */
-        *p++ = H5EA_SBLOCK_VERSION;
-
-        /* Extensible array type */
-        *p++ = sblock->hdr->cparam.cls->id;
-
-        /* Address of array header for array which owns this block */
-        H5F_addr_encode(f, &p, sblock->hdr->addr);
-
-        /* Offset of block in array */
-        UINT64ENCODE_VAR(p, sblock->block_off, sblock->hdr->arr_off_size);
-
-        /* Internal information */
-
-        /* Check for 'page init' bitmasks for this super block */
-        if(sblock->dblk_npages > 0) {
-            size_t tot_page_init_size = sblock->ndblks * sblock->dblk_page_init_size;        /* Compute total size of 'page init' buffer */
-
-            /* Store the 'page init' bitmasks */
-            HDmemcpy(p, sblock->page_init, tot_page_init_size);
-            p += tot_page_init_size;
-        } /* end if */
-
-        /* Encode addresses of data blocks in super block */
-        for(u = 0; u < sblock->ndblks; u++)
-            H5F_addr_encode(f, &p, sblock->dblk_addrs[u]);
-
-        /* Compute metadata checksum */
-        metadata_chksum = H5_checksum_metadata(buf, (size_t)(p - buf), 0);
-
-        /* Metadata checksum */
-        UINT32ENCODE(p, metadata_chksum);
-
-	/* Write the super block */
-        HDassert((size_t)(p - buf) == size);
-	if(H5F_block_write(f, H5FD_MEM_EARRAY_SBLOCK, addr, size, dxpl_id, buf) < 0)
-            H5E_THROW(H5E_WRITEERROR, "unable to save extensible array super block to disk")
-
-	sblock->cache_info.is_dirty = FALSE;
-    } /* end if */
-
-    if(destroy)
-        if(H5EA__cache_sblock_dest(f, sblock) < 0)
-            H5E_THROW(H5E_CANTFREE, "unable to destroy extensible array super block")
-
-CATCH
-
-    /* Release resources */
-    if(wb && H5WB_unwrap(wb) < 0)
-	H5E_THROW(H5E_CLOSEERROR, "can't close wrapped buffer")
-
-END_FUNC(STATIC)   /* end H5EA__cache_sblock_flush() */
+END_FUNC(STATIC)   /* end H5EA__cache_sblock_image_len() */
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5EA__cache_sblock_clear
+ * Function:	H5EA__cache_sblock_serialize
  *
- * Purpose:	Mark a extensible array super block in memory as non-dirty.
+ * Purpose:	Flushes a dirty object to disk.
  *
  * Return:	Non-negative on success/Negative on failure
  *
  * Programmer:	Quincey Koziol
- *		koziol@hdfgroup.org
- *		Sept 30 2008
+ *              koziol@hdfgroup.org
+ *              July 17, 2013
  *
  *-------------------------------------------------------------------------
  */
-BEGIN_FUNC(STATIC, ERR,
-herr_t, SUCCEED, FAIL,
-H5EA__cache_sblock_clear(H5F_t *f, H5EA_sblock_t *sblock, hbool_t destroy))
+BEGIN_FUNC(STATIC, NOERR,
+herr_t, SUCCEED, -,
+H5EA__cache_sblock_serialize(const H5F_t *f, void *_image, size_t H5_ATTR_UNUSED len,
+    void *_thing))
 
-    /* Sanity check */
+    /* Local variables */
+    H5EA_sblock_t *sblock = (H5EA_sblock_t *)_thing;      /* Pointer to the object to serialize */
+    uint8_t *image = (uint8_t *)_image;         /* Pointer into raw data buffer */
+    uint32_t metadata_chksum;   /* Computed metadata checksum value */
+    size_t u;                   /* Local index variable */
+
+    /* check arguments */
+    HDassert(f);
+    HDassert(image);
     HDassert(sblock);
+    HDassert(sblock->hdr);
 
-    /* Reset the dirty flag */
-    sblock->cache_info.is_dirty = FALSE;
+    /* Magic number */
+    HDmemcpy(image, H5EA_SBLOCK_MAGIC, (size_t)H5_SIZEOF_MAGIC);
+    image += H5_SIZEOF_MAGIC;
 
-    if(destroy)
-        if(H5EA__cache_sblock_dest(f, sblock) < 0)
-            H5E_THROW(H5E_CANTFREE, "unable to destroy extensible array super block")
+    /* Version # */
+    *image++ = H5EA_SBLOCK_VERSION;
 
-CATCH
+    /* Extensible array type */
+    *image++ = sblock->hdr->cparam.cls->id;
 
-END_FUNC(STATIC)   /* end H5EA__cache_sblock_clear() */
+    /* Address of array header for array which owns this block */
+    H5F_addr_encode(f, &image, sblock->hdr->addr);
 
-
-/*-------------------------------------------------------------------------
- * Function:	H5EA__cache_sblock_size
- *
- * Purpose:	Compute the size in bytes of a extensible array super block
- *		on disk, and return it in *size_ptr.  On failure,
- *		the value of *size_ptr is undefined.
- *
- * Return:	Non-negative on success/Negative on failure
- *
- * Programmer:	Quincey Koziol
- *		koziol@hdfgroup.org
- *		Sept 30 2008
- *
- *-------------------------------------------------------------------------
- */
-/* ARGSUSED */
-BEGIN_FUNC(STATIC, NOERR,
-herr_t, SUCCEED, -,
-H5EA__cache_sblock_size(const H5F_t H5_ATTR_UNUSED *f, const H5EA_sblock_t *sblock,
-    size_t *size_ptr))
+    /* Offset of block in array */
+    UINT64ENCODE_VAR(image, sblock->block_off, sblock->hdr->arr_off_size);
 
-    /* Sanity check */
-    HDassert(sblock);
-    HDassert(size_ptr);
+    /* Internal information */
+
+    /* Check for 'page init' bitmasks for this super block */
+    if(sblock->dblk_npages > 0) {
+        size_t tot_page_init_size = sblock->ndblks * sblock->dblk_page_init_size;        /* Compute total size of 'page init' buffer */
 
-    /* Set size value */
-    *size_ptr = sblock->size;
+        /* Store the 'page init' bitmasks */
+        HDmemcpy(image, sblock->page_init, tot_page_init_size);
+        image += tot_page_init_size;
+    } /* end if */
+
+    /* Encode addresses of data blocks in super block */
+    for(u = 0; u < sblock->ndblks; u++)
+        H5F_addr_encode(f, &image, sblock->dblk_addrs[u]);
+
+    /* Compute metadata checksum */
+    metadata_chksum = H5_checksum_metadata(_image, (size_t)(image - (uint8_t *)_image), 0);
+
+    /* Metadata checksum */
+    UINT32ENCODE(image, metadata_chksum);
+
+    /* Sanity check */
+    HDassert((size_t)(image - (uint8_t *)_image) <= len);
 
-END_FUNC(STATIC)   /* end H5EA__cache_sblock_size() */
+END_FUNC(STATIC)   /* end H5EA__cache_sblock_serialize() */
 
 
 /*-------------------------------------------------------------------------
@@ -1273,7 +1161,10 @@ END_FUNC(STATIC)   /* end H5EA__cache_sblock_size() */
  */
 BEGIN_FUNC(STATIC, ERR,
 herr_t, SUCCEED, FAIL,
-H5EA__cache_sblock_notify(H5AC_notify_action_t action, H5EA_sblock_t *sblock))
+H5EA__cache_sblock_notify(H5AC_notify_action_t action, void *_thing))
+
+    /* Local variables */
+    H5EA_sblock_t *sblock = (H5EA_sblock_t *)_thing;      /* Pointer to the object */
 
     /* Sanity check */
     HDassert(sblock);
@@ -1281,11 +1172,16 @@ H5EA__cache_sblock_notify(H5AC_notify_action_t action, H5EA_sblock_t *sblock))
     /* Determine which action to take */
     switch(action) {
         case H5AC_NOTIFY_ACTION_AFTER_INSERT:
+        case H5AC_NOTIFY_ACTION_AFTER_LOAD:
             /* Create flush dependency on index block */
             if(H5EA__create_flush_depend((H5AC_info_t *)sblock->parent, (H5AC_info_t *)sblock) < 0)
                 H5E_THROW(H5E_CANTDEPEND, "unable to create flush dependency between super block and index block, address = %llu", (unsigned long long)sblock->addr)
             break;
 
+	case H5AC_NOTIFY_ACTION_AFTER_FLUSH:
+	    /* do nothing */
+	    break;
+
         case H5AC_NOTIFY_ACTION_BEFORE_EVICT:
             /* Destroy flush dependency on index block */
             if(H5EA__destroy_flush_depend((H5AC_info_t *)sblock->parent, (H5AC_info_t *)sblock) < 0)
@@ -1302,135 +1198,158 @@ END_FUNC(STATIC)   /* end H5EA__cache_sblock_notify() */
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5EA__cache_sblock_dest
+ * Function:	H5EA__cache_sblock_free_icr
  *
- * Purpose:	Destroys an extensible array super block in memory.
+ * Purpose:	Destroy/release an "in core representation" of a data
+ *              structure
  *
  * Return:	Non-negative on success/Negative on failure
  *
  * Programmer:	Quincey Koziol
- *		koziol@hdfgroup.org
- *		Sep 30 2008
+ *              koziol@hdfgroup.org
+ *              July 17, 2013
  *
  *-------------------------------------------------------------------------
  */
 BEGIN_FUNC(STATIC, ERR,
 herr_t, SUCCEED, FAIL,
-H5EA__cache_sblock_dest(H5F_t *f, H5EA_sblock_t *sblock))
+H5EA__cache_sblock_free_icr(void *thing))
 
-    /* Sanity check */
-    HDassert(f);
-    HDassert(sblock);
+    /* Check arguments */
+    HDassert(thing);
 
-    /* Verify that super block is clean */
-    HDassert(sblock->cache_info.is_dirty == FALSE);
+    /* Release the extensible array super block */
+    if(H5EA__sblock_dest((H5EA_sblock_t *)thing) < 0)
+        H5E_THROW(H5E_CANTFREE, "can't free extensible array super block")
 
-    /* If we're going to free the space on disk, the address must be valid */
-    HDassert(!sblock->cache_info.free_file_space_on_destroy || H5F_addr_defined(sblock->cache_info.addr));
+CATCH
 
-    /* Check for freeing file space for extensible array super block */
-    if(sblock->cache_info.free_file_space_on_destroy) {
-        /* Sanity check address */
-        HDassert(H5F_addr_eq(sblock->addr, sblock->cache_info.addr));
+END_FUNC(STATIC)   /* end H5EA__cache_sblock_free_icr() */
 
-        /* Release the space on disk */
-        /* (XXX: Nasty usage of internal DXPL value! -QAK) */
-        if(H5MF_xfree(f, H5FD_MEM_EARRAY_SBLOCK, H5AC_dxpl_id, sblock->cache_info.addr, (hsize_t)sblock->size) < 0)
-            H5E_THROW(H5E_CANTFREE, "unable to free extensible array super block")
-    } /* end if */
+
+/*-------------------------------------------------------------------------
+ * Function:    H5EA__cache_dblock_get_load_size
+ *
+ * Purpose:     Compute the size of the data structure on disk.
+ *
+ * Return:      Non-negative on success/Negative on failure
+ *
+ * Programmer:  Quincey Koziol
+ *              koziol@hdfgroup.org
+ *              July 17, 2013
+ *
+ *-------------------------------------------------------------------------
+ */
+BEGIN_FUNC(STATIC, NOERR,
+herr_t, SUCCEED, -,
+H5EA__cache_dblock_get_load_size(const void *_udata, size_t *image_len))
 
-    /* Release the super block */
-    if(H5EA__sblock_dest(sblock) < 0)
-        H5E_THROW(H5E_CANTFREE, "can't free extensible array super block")
+    /* Local variables */
+    const H5EA_dblock_cache_ud_t *udata = (const H5EA_dblock_cache_ud_t *)_udata;      /* User data */
+    H5EA_dblock_t dblock;           /* Fake data block for computing size */
 
-CATCH
+    /* Check arguments */
+    HDassert(udata);
+    HDassert(udata->hdr);
+    HDassert(udata->parent);
+    HDassert(udata->nelmts > 0);
+    HDassert(image_len);
+
+    /* Set up fake data block for computing size on disk */
+    /* (Note: extracted from H5EA__dblock_alloc) */
+    HDmemset(&dblock, 0, sizeof(dblock));
+
+    /* need to set:
+     * 
+     *    dblock.hdr
+     *    dblock.npages
+     *    dblock.nelmts
+     *
+     * before we invoke either H5EA_DBLOCK_PREFIX_SIZE() or 
+     * H5EA_DBLOCK_SIZE().
+     */
+    dblock.hdr = udata->hdr;
+    dblock.nelmts = udata->nelmts;
+
+    if(udata->nelmts > udata->hdr->dblk_page_nelmts) {
+        /* Set the # of pages in the direct block */
+        dblock.npages = udata->nelmts / udata->hdr->dblk_page_nelmts;
+        HDassert(udata->nelmts==(dblock.npages * udata->hdr->dblk_page_nelmts));
+    } /* end if */
 
-END_FUNC(STATIC)   /* end H5EA__cache_sblock_dest() */
+    /* Set the image length size */
+    if(!dblock.npages)
+        *image_len = H5EA_DBLOCK_SIZE(&dblock);
+    else
+        *image_len = H5EA_DBLOCK_PREFIX_SIZE(&dblock);
+
+END_FUNC(STATIC)   /* end H5EA__cache_dblock_get_load_size() */
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5EA__cache_dblock_load
+ * Function:	H5EA__cache_dblock_deserialize
  *
- * Purpose:	Loads an extensible array data block from the disk.
+ * Purpose:	Loads a data structure from the disk.
  *
- * Return:	Success:	Pointer to a new extensible array data block
+ * Return:	Success:	Pointer to a new B-tree.
  *		Failure:	NULL
  *
  * Programmer:	Quincey Koziol
- *		koziol@hdfgroup.org
- *		Sep 16 2008
+ *              koziol@hdfgroup.org
+ *              July 17, 2013
  *
  *-------------------------------------------------------------------------
  */
 BEGIN_FUNC(STATIC, ERR,
-H5EA_dblock_t *, NULL, NULL,
-H5EA__cache_dblock_load(H5F_t *f, hid_t dxpl_id, haddr_t addr, void *_udata))
+void *, NULL, NULL,
+H5EA__cache_dblock_deserialize(const void *_image, size_t len,
+    void *_udata, hbool_t H5_ATTR_UNUSED *dirty))
 
     /* Local variables */
     H5EA_dblock_t	*dblock = NULL; /* Data block info */
-    H5EA_dblock_cache_ud_t *udata = (H5EA_dblock_cache_ud_t *)_udata;      /* User data for loading data block */
-    size_t		size;           /* Data block size */
-    H5WB_t              *wb = NULL;     /* Wrapped buffer for data block data */
-    uint8_t             dblock_buf[H5EA_DBLOCK_BUF_SIZE]; /* Buffer for data block */
-    uint8_t		*buf;           /* Pointer to data block buffer */
-    const uint8_t	*p;             /* Pointer into raw data buffer */
+    H5EA_dblock_cache_ud_t *udata = (H5EA_dblock_cache_ud_t *)_udata;      /* User data */
+    const uint8_t	*image = (const uint8_t *)_image;       /* Pointer into raw data buffer */
     uint32_t            stored_chksum;  /* Stored metadata checksum value */
     uint32_t            computed_chksum; /* Computed metadata checksum value */
     haddr_t             arr_addr;       /* Address of array header in the file */
 
-    /* Sanity check */
-    HDassert(f);
-    HDassert(H5F_addr_defined(addr));
-    HDassert(udata && udata->hdr && udata->parent && udata->nelmts > 0);
+    /* Check arguments */
+    HDassert(udata);
+    HDassert(udata->hdr);
+    HDassert(udata->parent);
+    HDassert(udata->nelmts > 0);
+    HDassert(H5F_addr_defined(udata->dblk_addr));
 
     /* Allocate the extensible array data block */
     if(NULL == (dblock = H5EA__dblock_alloc(udata->hdr, udata->parent, udata->nelmts)))
 	H5E_THROW(H5E_CANTALLOC, "memory allocation failed for extensible array data block")
 
-    /* Set the extensible array data block's information */
-    dblock->addr = addr;
-
-    /* Wrap the local buffer for serialized info */
-    if(NULL == (wb = H5WB_wrap(dblock_buf, sizeof(dblock_buf))))
-	H5E_THROW(H5E_CANTINIT, "can't wrap buffer")
+    HDassert(((!dblock->npages) && (len == H5EA_DBLOCK_SIZE(dblock))) || 
+             (len == H5EA_DBLOCK_PREFIX_SIZE(dblock)));
 
-    /* Compute the size of the extensible array data block on disk */
-    if(!dblock->npages)
-        size = H5EA_DBLOCK_SIZE(dblock);
-    else
-        size = H5EA_DBLOCK_PREFIX_SIZE(dblock);
-
-    /* Get a pointer to a buffer that's large enough for serialized info */
-    if(NULL == (buf = (uint8_t *)H5WB_actual(wb, size)))
-	H5E_THROW(H5E_CANTGET, "can't get actual buffer")
-
-    /* Read data block from disk */
-    if(H5F_block_read(f, H5FD_MEM_EARRAY_DBLOCK, addr, size, dxpl_id, buf) < 0)
-	H5E_THROW(H5E_READERROR, "can't read extensible array data block")
-
-    /* Get temporary pointer to serialized header */
-    p = buf;
+    /* Set the extensible array data block's information */
+    dblock->addr = udata->dblk_addr;
 
     /* Magic number */
-    if(HDmemcmp(p, H5EA_DBLOCK_MAGIC, (size_t)H5_SIZEOF_MAGIC))
+    if(HDmemcmp(image, H5EA_DBLOCK_MAGIC, (size_t)H5_SIZEOF_MAGIC))
 	H5E_THROW(H5E_BADVALUE, "wrong extensible array data block signature")
-    p += H5_SIZEOF_MAGIC;
+    image += H5_SIZEOF_MAGIC;
 
     /* Version */
-    if(*p++ != H5EA_DBLOCK_VERSION)
+    if(*image++ != H5EA_DBLOCK_VERSION)
 	H5E_THROW(H5E_VERSION, "wrong extensible array data block version")
 
     /* Extensible array type */
-    if(*p++ != (uint8_t)udata->hdr->cparam.cls->id)
+    if(*image++ != (uint8_t)udata->hdr->cparam.cls->id)
 	H5E_THROW(H5E_BADTYPE, "incorrect extensible array class")
 
     /* Address of header for array that owns this block (just for file integrity checks) */
-    H5F_addr_decode(f, &p, &arr_addr);
+    H5F_addr_decode(udata->hdr->f, &image, &arr_addr);
     if(H5F_addr_ne(arr_addr, udata->hdr->addr))
 	H5E_THROW(H5E_BADVALUE, "wrong extensible array header address")
 
     /* Offset of block within the array's address space */
-    UINT64DECODE_VAR(p, dblock->block_off, udata->hdr->arr_off_size);
+    UINT64DECODE_VAR(image, dblock->block_off, udata->hdr->arr_off_size);
 
     /* Internal information */
 
@@ -1438,26 +1357,27 @@ H5EA__cache_dblock_load(H5F_t *f, hid_t dxpl_id, haddr_t addr, void *_udata))
     if(!dblock->npages) {
         /* Decode elements in data block */
         /* Convert from raw elements on disk into native elements in memory */
-        if((udata->hdr->cparam.cls->decode)(p, dblock->elmts, udata->nelmts, udata->hdr->cb_ctx) < 0)
+        if((udata->hdr->cparam.cls->decode)(image, dblock->elmts, udata->nelmts, udata->hdr->cb_ctx) < 0)
             H5E_THROW(H5E_CANTDECODE, "can't decode extensible array data elements")
-        p += (udata->nelmts * udata->hdr->cparam.raw_elmt_size);
+        image += (udata->nelmts * udata->hdr->cparam.raw_elmt_size);
     } /* end if */
 
     /* Sanity check */
     /* (allow for checksum not decoded yet) */
-    HDassert((size_t)(p - buf) == (size - H5EA_SIZEOF_CHKSUM));
+    HDassert((size_t)(image - (const uint8_t *)_image) == (len - H5EA_SIZEOF_CHKSUM));
 
     /* Set the data block's size */
+    /* (Note: This is not the same as the image length, for paged data blocks) */
     dblock->size = H5EA_DBLOCK_SIZE(dblock);
 
     /* Compute checksum on data block */
-    computed_chksum = H5_checksum_metadata(buf, (size_t)(p - buf), 0);
+    computed_chksum = H5_checksum_metadata(_image, (size_t)(image - (const uint8_t *)_image), 0);
 
     /* Metadata checksum */
-    UINT32DECODE(p, stored_chksum);
+    UINT32DECODE(image, stored_chksum);
 
     /* Sanity check */
-    HDassert((size_t)(p - buf) == size);
+    HDassert((size_t)(image - (const uint8_t *)_image) == len);
 
     /* Verify checksum */
     if(stored_chksum != computed_chksum)
@@ -1469,151 +1389,116 @@ H5EA__cache_dblock_load(H5F_t *f, hid_t dxpl_id, haddr_t addr, void *_udata))
 CATCH
 
     /* Release resources */
-    if(wb && H5WB_unwrap(wb) < 0)
-	H5E_THROW(H5E_CLOSEERROR, "can't close wrapped buffer")
     if(!ret_value)
         if(dblock && H5EA__dblock_dest(dblock) < 0)
             H5E_THROW(H5E_CANTFREE, "unable to destroy extensible array data block")
 
-END_FUNC(STATIC)   /* end H5EA__cache_dblock_load() */
+END_FUNC(STATIC)   /* end H5EA__cache_dblock_deserialize() */
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5EA__cache_dblock_flush
+ * Function:    H5EA__cache_dblock_image_len
  *
- * Purpose:	Flushes a dirty extensible array data block to disk.
+ * Purpose:     Compute the size of the data structure on disk.
  *
- * Return:	Non-negative on success/Negative on failure
+ * Return:      Non-negative on success/Negative on failure
  *
- * Programmer:	Quincey Koziol
- *		koziol@hdfgroup.org
- *		Sep 18 2008
+ * Programmer:  Quincey Koziol
+ *              koziol@hdfgroup.org
+ *              July 17, 2013
  *
  *-------------------------------------------------------------------------
  */
-BEGIN_FUNC(STATIC, ERR,
-herr_t, SUCCEED, FAIL,
-H5EA__cache_dblock_flush(H5F_t *f, hid_t dxpl_id, hbool_t destroy, haddr_t addr,
-    H5EA_dblock_t *dblock, unsigned H5_ATTR_UNUSED * flags_ptr))
+BEGIN_FUNC(STATIC, NOERR,
+herr_t, SUCCEED, -,
+H5EA__cache_dblock_image_len(const void *_thing, size_t *image_len,
+    hbool_t H5_ATTR_UNUSED *compressed_ptr, size_t H5_ATTR_UNUSED *compressed_image_len_ptr))
 
     /* Local variables */
-    H5WB_t *wb = NULL;                  /* Wrapped buffer for serializing data */
-    uint8_t ser_buf[H5EA_DBLOCK_BUF_SIZE]; /* Serialization buffer */
+    const H5EA_dblock_t *dblock = (const H5EA_dblock_t *)_thing;      /* Pointer to the object */
 
-    /* Sanity check */
-    HDassert(f);
-    HDassert(H5F_addr_defined(addr));
+    /* Check arguments */
     HDassert(dblock);
-    HDassert(dblock->hdr);
+    HDassert(image_len);
 
-    if(dblock->cache_info.is_dirty) {
-        uint8_t	*buf;           /* Temporary raw data buffer */
-        uint8_t *p;             /* Pointer into raw data buffer */
-        size_t	size;           /* Index block size on disk */
-        uint32_t metadata_chksum; /* Computed metadata checksum value */
-
-        /* Wrap the local buffer for serialized info */
-        if(NULL == (wb = H5WB_wrap(ser_buf, sizeof(ser_buf))))
-            H5E_THROW(H5E_CANTINIT, "can't wrap buffer")
-
-        /* Compute the size of the data block on disk */
-        if(!dblock->npages)
-            size = dblock->size;
-        else
-            size = H5EA_DBLOCK_PREFIX_SIZE(dblock);
-
-        /* Get a pointer to a buffer that's large enough for serialized info */
-        if(NULL == (buf = (uint8_t *)H5WB_actual(wb, size)))
-            H5E_THROW(H5E_CANTGET, "can't get actual buffer")
-
-        /* Get temporary pointer to serialized info */
-        p = buf;
-
-        /* Magic number */
-        HDmemcpy(p, H5EA_DBLOCK_MAGIC, (size_t)H5_SIZEOF_MAGIC);
-        p += H5_SIZEOF_MAGIC;
-
-        /* Version # */
-        *p++ = H5EA_DBLOCK_VERSION;
-
-        /* Extensible array type */
-        *p++ = dblock->hdr->cparam.cls->id;
-
-        /* Address of array header for array which owns this block */
-        H5F_addr_encode(f, &p, dblock->hdr->addr);
-
-        /* Offset of block in array */
-        UINT64ENCODE_VAR(p, dblock->block_off, dblock->hdr->arr_off_size);
-
-        /* Internal information */
-
-        /* Only encode elements if the data block is not paged */
-        if(!dblock->npages) {
-            /* Encode elements in data block */
-
-            /* Convert from native elements in memory into raw elements on disk */
-            if((dblock->hdr->cparam.cls->encode)(p, dblock->elmts, dblock->nelmts, dblock->hdr->cb_ctx) < 0)
-                H5E_THROW(H5E_CANTENCODE, "can't encode extensible array data elements")
-            p += (dblock->nelmts * dblock->hdr->cparam.raw_elmt_size);
-        } /* end if */
-
-        /* Compute metadata checksum */
-        metadata_chksum = H5_checksum_metadata(buf, (size_t)(p - buf), 0);
-
-        /* Metadata checksum */
-        UINT32ENCODE(p, metadata_chksum);
-
-	/* Write the data block */
-        HDassert((size_t)(p - buf) == size);
-	if(H5F_block_write(f, H5FD_MEM_EARRAY_DBLOCK, addr, size, dxpl_id, buf) < 0)
-            H5E_THROW(H5E_WRITEERROR, "unable to save extensible array data block to disk")
-
-	dblock->cache_info.is_dirty = FALSE;
-    } /* end if */
-
-    if(destroy)
-        if(H5EA__cache_dblock_dest(f, dblock) < 0)
-            H5E_THROW(H5E_CANTFREE, "unable to destroy extensible array data block")
-
-CATCH
-
-    /* Release resources */
-    if(wb && H5WB_unwrap(wb) < 0)
-	H5E_THROW(H5E_CLOSEERROR, "can't close wrapped buffer")
+    /* Set the image length size */
+    if(!dblock->npages)
+        *image_len = dblock->size;
+    else
+        *image_len = (size_t)H5EA_DBLOCK_PREFIX_SIZE(dblock);
 
-END_FUNC(STATIC)   /* end H5EA__cache_dblock_flush() */
+END_FUNC(STATIC)   /* end H5EA__cache_dblock_image_len() */
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5EA__cache_dblock_clear
+ * Function:	H5EA__cache_dblock_serialize
  *
- * Purpose:	Mark a extensible array data block in memory as non-dirty.
+ * Purpose:	Flushes a dirty object to disk.
  *
  * Return:	Non-negative on success/Negative on failure
  *
  * Programmer:	Quincey Koziol
- *		koziol@hdfgroup.org
- *		Sept 18 2008
+ *              koziol@hdfgroup.org
+ *              July 17, 2013
  *
  *-------------------------------------------------------------------------
  */
 BEGIN_FUNC(STATIC, ERR,
 herr_t, SUCCEED, FAIL,
-H5EA__cache_dblock_clear(H5F_t *f, H5EA_dblock_t *dblock, hbool_t destroy))
+H5EA__cache_dblock_serialize(const H5F_t *f, void *_image, size_t H5_ATTR_UNUSED len,
+    void *_thing))
 
-    /* Sanity check */
+    /* Local variables */
+    H5EA_dblock_t *dblock = (H5EA_dblock_t *)_thing;      /* Pointer to the object to serialize */
+    uint8_t *image = (uint8_t *)_image;         /* Pointer into raw data buffer */
+    uint32_t metadata_chksum;   /* Computed metadata checksum value */
+
+    /* check arguments */
+    HDassert(f);
+    HDassert(image);
     HDassert(dblock);
+    HDassert(dblock->hdr);
 
-    /* Reset the dirty flag */
-    dblock->cache_info.is_dirty = FALSE;
+    /* Magic number */
+    HDmemcpy(image, H5EA_DBLOCK_MAGIC, (size_t)H5_SIZEOF_MAGIC);
+    image += H5_SIZEOF_MAGIC;
 
-    if(destroy)
-        if(H5EA__cache_dblock_dest(f, dblock) < 0)
-            H5E_THROW(H5E_CANTFREE, "unable to destroy extensible array data block")
+    /* Version # */
+    *image++ = H5EA_DBLOCK_VERSION;
+
+    /* Extensible array type */
+    *image++ = dblock->hdr->cparam.cls->id;
+
+    /* Address of array header for array which owns this block */
+    H5F_addr_encode(f, &image, dblock->hdr->addr);
+
+    /* Offset of block in array */
+    UINT64ENCODE_VAR(image, dblock->block_off, dblock->hdr->arr_off_size);
+
+    /* Internal information */
+
+    /* Only encode elements if the data block is not paged */
+    if(!dblock->npages) {
+        /* Encode elements in data block */
+
+        /* Convert from native elements in memory into raw elements on disk */
+        if((dblock->hdr->cparam.cls->encode)(image, dblock->elmts, dblock->nelmts, dblock->hdr->cb_ctx) < 0)
+            H5E_THROW(H5E_CANTENCODE, "can't encode extensible array data elements")
+        image += (dblock->nelmts * dblock->hdr->cparam.raw_elmt_size);
+    } /* end if */
+
+    /* Compute metadata checksum */
+    metadata_chksum = H5_checksum_metadata(_image, (size_t)(image - (uint8_t *)_image), 0);
+
+    /* Metadata checksum */
+    UINT32ENCODE(image, metadata_chksum);
+
+    /* Sanity check */
+    HDassert((size_t)(image - (uint8_t *)_image) <= len);
 
 CATCH
 
-END_FUNC(STATIC)   /* end H5EA__cache_dblock_clear() */
+END_FUNC(STATIC)   /* end H5EA__cache_dblock_serialize() */
 
 
 /*-------------------------------------------------------------------------
@@ -1631,19 +1516,27 @@ END_FUNC(STATIC)   /* end H5EA__cache_dblock_clear() */
  */
 BEGIN_FUNC(STATIC, ERR,
 herr_t, SUCCEED, FAIL,
-H5EA__cache_dblock_notify(H5AC_notify_action_t action, H5EA_dblock_t *dblock))
+H5EA__cache_dblock_notify(H5AC_notify_action_t action, void *_thing))
 
-    /* Sanity check */
+    /* Local variables */
+    H5EA_dblock_t *dblock = (H5EA_dblock_t *)_thing;      /* Pointer to the object */
+
+    /* Check arguments */
     HDassert(dblock);
 
     /* Determine which action to take */
     switch(action) {
         case H5AC_NOTIFY_ACTION_AFTER_INSERT:
+        case H5AC_NOTIFY_ACTION_AFTER_LOAD:
             /* Create flush dependency on parent */
             if(H5EA__create_flush_depend((H5AC_info_t *)dblock->parent, (H5AC_info_t *)dblock) < 0)
                 H5E_THROW(H5E_CANTDEPEND, "unable to create flush dependency between data block and parent, address = %llu", (unsigned long long)dblock->addr)
             break;
 
+	case H5AC_NOTIFY_ACTION_AFTER_FLUSH:
+	    /* do nothing */
+	    break;
+
         case H5AC_NOTIFY_ACTION_BEFORE_EVICT:
             /* Destroy flush dependency on parent */
             if(H5EA__destroy_flush_depend((H5AC_info_t *)dblock->parent, (H5AC_info_t *)dblock) < 0)
@@ -1660,171 +1553,175 @@ END_FUNC(STATIC)   /* end H5EA__cache_dblock_notify() */
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5EA__cache_dblock_size
+ * Function:	H5EA__cache_dblock_free_icr
  *
- * Purpose:	Compute the size in bytes of a extensible array data block
- *		on disk, and return it in *size_ptr.  On failure,
- *		the value of *size_ptr is undefined.
+ * Purpose:	Destroy/release an "in core representation" of a data
+ *              structure
  *
  * Return:	Non-negative on success/Negative on failure
  *
  * Programmer:	Quincey Koziol
- *		koziol@hdfgroup.org
- *		Sept 18 2008
+ *              koziol@hdfgroup.org
+ *              July 17, 2013
  *
  *-------------------------------------------------------------------------
  */
-/* ARGSUSED */
-BEGIN_FUNC(STATIC, NOERR,
-herr_t, SUCCEED, -,
-H5EA__cache_dblock_size(const H5F_t H5_ATTR_UNUSED *f, const H5EA_dblock_t *dblock,
-    size_t *size_ptr))
+BEGIN_FUNC(STATIC, ERR,
+herr_t, SUCCEED, FAIL,
+H5EA__cache_dblock_free_icr(void *thing))
 
-    /* Sanity check */
-    HDassert(f);
-    HDassert(dblock);
-    HDassert(size_ptr);
+    /* Check arguments */
+    HDassert(thing);
 
-    /* Set size value */
-    if(!dblock->npages)
-        *size_ptr = dblock->size;
-    else
-        *size_ptr = H5EA_DBLOCK_PREFIX_SIZE(dblock);
+    /* Release the extensible array data block */
+    if(H5EA__dblock_dest((H5EA_dblock_t *)thing) < 0)
+        H5E_THROW(H5E_CANTFREE, "can't free extensible array data block")
+
+CATCH
 
-END_FUNC(STATIC)   /* end H5EA__cache_dblock_size() */
+END_FUNC(STATIC)   /* end H5EA__cache_dblock_free_icr() */
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5EA__cache_dblock_dest
+ * Function:    H5EA__cache_dblock_fsf_size
  *
- * Purpose:	Destroys an extensible array data block in memory.
+ * Purpose:     Tell the metadata cache the actual amount of file space
+ *              to free when a dblock entry is destroyed with the free
+ *              file space block set.
  *
- * Return:	Non-negative on success/Negative on failure
+ *              This function is needed when the data block is paged, as
+ *              the datablock header and all its pages are allocted as a
+ *              single contiguous chunk of file space, and must be
+ *              deallocated the same way.
  *
- * Programmer:	Quincey Koziol
- *		koziol@hdfgroup.org
- *		Sep 18 2008
+ *              The size of the chunk of memory in which the dblock
+ *              header and all its pages is stored in the size field,
+ *              so we simply pass that value back to the cache.
+ *
+ *              If the datablock is not paged, then the size field of
+ *              the cache_info contains the correct size.  However this
+ *              value will be the same as the size field, so we return
+ *              the contents of the size field to the cache in this case
+ *              as well.
+ *
+ * Return:      Non-negative on success/Negative on failure
+ *
+ * Programmer:  John Mainzer
+ *              12/5/14
  *
  *-------------------------------------------------------------------------
  */
-/* ARGSUSED */
-BEGIN_FUNC(STATIC, ERR,
-herr_t, SUCCEED, FAIL,
-H5EA__cache_dblock_dest(H5F_t *f, H5EA_dblock_t *dblock))
+BEGIN_FUNC(STATIC, NOERR,
+herr_t, SUCCEED, -,
+H5EA__cache_dblock_fsf_size(const void *_thing, size_t *fsf_size))
 
-    /* Sanity check */
-    HDassert(f);
+    /* Local variables */
+    const H5EA_dblock_t *dblock = (const H5EA_dblock_t *)_thing;        /* Pointer to the object */
+
+    /* Check arguments */
     HDassert(dblock);
+    HDassert(dblock->cache_info.magic == H5C__H5C_CACHE_ENTRY_T_MAGIC);
+    HDassert(dblock->cache_info.type == H5AC_EARRAY_DBLOCK);
+    HDassert(fsf_size);
 
-    /* Verify that data block is clean */
-    HDassert(dblock->cache_info.is_dirty == FALSE);
+    *fsf_size = dblock->size;
 
-    /* If we're going to free the space on disk, the address must be valid */
-    HDassert(!dblock->cache_info.free_file_space_on_destroy || H5F_addr_defined(dblock->cache_info.addr));
+END_FUNC(STATIC)   /* end H5EA__cache_dblock_fsf_size() */
 
-    /* Check for freeing file space for extensible array data block */
-    if(dblock->cache_info.free_file_space_on_destroy) {
-        /* Sanity check address */
-        HDassert(H5F_addr_eq(dblock->addr, dblock->cache_info.addr));
+
+/*-------------------------------------------------------------------------
+ * Function:    H5EA__cache_dblk_page_get_load_size
+ *
+ * Purpose:     Compute the size of the data structure on disk.
+ *
+ * Return:      Non-negative on success/Negative on failure
+ *
+ * Programmer:  Quincey Koziol
+ *              koziol@hdfgroup.org
+ *              July 17, 2013
+ *
+ *-------------------------------------------------------------------------
+ */
+BEGIN_FUNC(STATIC, NOERR,
+herr_t, SUCCEED, -,
+H5EA__cache_dblk_page_get_load_size(const void *_udata, size_t *image_len))
 
-        /* Release the space on disk */
-        /* (Includes space for pages!) */
-        /* (XXX: Nasty usage of internal DXPL value! -QAK) */
-        if(H5MF_xfree(f, H5FD_MEM_EARRAY_DBLOCK, H5AC_dxpl_id, dblock->cache_info.addr, (hsize_t)dblock->size) < 0)
-            H5E_THROW(H5E_CANTFREE, "unable to free extensible array data block")
-    } /* end if */
+    /* Local variables */
+    const H5EA_dblk_page_cache_ud_t *udata = (const H5EA_dblk_page_cache_ud_t *)_udata;      /* User data */
 
-    /* Release the data block */
-    if(H5EA__dblock_dest(dblock) < 0)
-        H5E_THROW(H5E_CANTFREE, "can't free extensible array data block")
+    /* Check arguments */
+    HDassert(udata);
+    HDassert(udata->hdr);
+    HDassert(udata->parent);
+    HDassert(image_len);
 
-CATCH
+    *image_len = (size_t)H5EA_DBLK_PAGE_SIZE(udata->hdr);
 
-END_FUNC(STATIC)   /* end H5EA__cache_dblock_dest() */
+END_FUNC(STATIC)   /* end H5EA__cache_dblk_page_get_load_size() */
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5EA__cache_dblk_page_load
+ * Function:	H5EA__cache_dblk_page_deserialize
  *
- * Purpose:	Loads an extensible array data block page from the disk.
+ * Purpose:	Loads a data structure from the disk.
  *
- * Return:	Success:	Pointer to a new extensible array data block page
+ * Return:	Success:	Pointer to a new B-tree.
  *		Failure:	NULL
  *
  * Programmer:	Quincey Koziol
- *		koziol@hdfgroup.org
- *		Nov 20 2008
+ *              koziol@hdfgroup.org
+ *              July 17, 2013
  *
  *-------------------------------------------------------------------------
  */
 BEGIN_FUNC(STATIC, ERR,
-H5EA_dblk_page_t *, NULL, NULL,
-H5EA__cache_dblk_page_load(H5F_t *f, hid_t dxpl_id, haddr_t addr, void *_udata))
+void *, NULL, NULL,
+H5EA__cache_dblk_page_deserialize(const void *_image, size_t len,
+    void *_udata, hbool_t H5_ATTR_UNUSED *dirty))
 
     /* Local variables */
     H5EA_dblk_page_t	*dblk_page = NULL; /* Data block page info */
     H5EA_dblk_page_cache_ud_t *udata = (H5EA_dblk_page_cache_ud_t *)_udata;      /* User data for loading data block page */
-    size_t		size;           /* Data block page size */
-    H5WB_t              *wb = NULL;     /* Wrapped buffer for data block page data */
-    uint8_t             dblk_page_buf[H5EA_DBLK_PAGE_BUF_SIZE]; /* Buffer for data block page */
-    uint8_t		*buf;           /* Pointer to data block page buffer */
-    const uint8_t	*p;             /* Pointer into raw data buffer */
+    const uint8_t	*image = (const uint8_t *)_image;       /* Pointer into raw data buffer */
     uint32_t            stored_chksum;  /* Stored metadata checksum value */
     uint32_t            computed_chksum; /* Computed metadata checksum value */
 
     /* Sanity check */
-    HDassert(f);
-    HDassert(H5F_addr_defined(addr));
-    HDassert(udata && udata->hdr && udata->parent);
+    HDassert(udata);
+    HDassert(udata->hdr);
+    HDassert(udata->parent);
+    HDassert(H5F_addr_defined(udata->dblk_page_addr));
 
     /* Allocate the extensible array data block page */
     if(NULL == (dblk_page = H5EA__dblk_page_alloc(udata->hdr, udata->parent)))
 	H5E_THROW(H5E_CANTALLOC, "memory allocation failed for extensible array data block page")
 
-    /* Set the extensible array data block's information */
-    dblk_page->addr = addr;
-
-    /* Wrap the local buffer for serialized info */
-    if(NULL == (wb = H5WB_wrap(dblk_page_buf, sizeof(dblk_page_buf))))
-	H5E_THROW(H5E_CANTINIT, "can't wrap buffer")
-
-    /* Compute the size of the extensible array data block page on disk */
-    size = H5EA_DBLK_PAGE_SIZE(udata->hdr);
-
-    /* Get a pointer to a buffer that's large enough for serialized info */
-    if(NULL == (buf = (uint8_t *)H5WB_actual(wb, size)))
-	H5E_THROW(H5E_CANTGET, "can't get actual buffer")
-
-    /* Read data block page from disk */
-    if(H5F_block_read(f, H5FD_MEM_EARRAY_DBLK_PAGE, addr, size, dxpl_id, buf) < 0)
-	H5E_THROW(H5E_READERROR, "can't read extensible array data block page")
-
-    /* Get temporary pointer to serialized header */
-    p = buf;
+    /* Set the extensible array data block page's information */
+    dblk_page->addr = udata->dblk_page_addr;
 
     /* Internal information */
 
     /* Decode elements in data block page */
     /* Convert from raw elements on disk into native elements in memory */
-    if((udata->hdr->cparam.cls->decode)(p, dblk_page->elmts, udata->hdr->dblk_page_nelmts, udata->hdr->cb_ctx) < 0)
+    if((udata->hdr->cparam.cls->decode)(image, dblk_page->elmts, udata->hdr->dblk_page_nelmts, udata->hdr->cb_ctx) < 0)
         H5E_THROW(H5E_CANTDECODE, "can't decode extensible array data elements")
-    p += (udata->hdr->dblk_page_nelmts * udata->hdr->cparam.raw_elmt_size);
+    image += (udata->hdr->dblk_page_nelmts * udata->hdr->cparam.raw_elmt_size);
 
     /* Sanity check */
     /* (allow for checksum not decoded yet) */
-    HDassert((size_t)(p - buf) == (size - H5EA_SIZEOF_CHKSUM));
+    HDassert((size_t)(image - (const uint8_t *)_image) == (len - H5EA_SIZEOF_CHKSUM));
 
     /* Set the data block page's size */
-    dblk_page->size = size;
+    dblk_page->size = len;
 
-    /* Compute checksum on data block */
-    computed_chksum = H5_checksum_metadata(buf, (size_t)(p - buf), 0);
+    /* Compute checksum on data block page */
+    computed_chksum = H5_checksum_metadata(_image, (size_t)(image - (const uint8_t *)_image), 0);
 
     /* Metadata checksum */
-    UINT32DECODE(p, stored_chksum);
+    UINT32DECODE(image, stored_chksum);
 
     /* Sanity check */
-    HDassert((size_t)(p - buf) == dblk_page->size);
+    HDassert((size_t)(image - (const uint8_t *)_image) == dblk_page->size);
 
     /* Verify checksum */
     if(stored_chksum != computed_chksum)
@@ -1836,129 +1733,94 @@ H5EA__cache_dblk_page_load(H5F_t *f, hid_t dxpl_id, haddr_t addr, void *_udata))
 CATCH
 
     /* Release resources */
-    if(wb && H5WB_unwrap(wb) < 0)
-	H5E_THROW(H5E_CLOSEERROR, "can't close wrapped buffer")
     if(!ret_value)
         if(dblk_page && H5EA__dblk_page_dest(dblk_page) < 0)
             H5E_THROW(H5E_CANTFREE, "unable to destroy extensible array data block page")
 
-END_FUNC(STATIC)   /* end H5EA__cache_dblk_page_load() */
+END_FUNC(STATIC)   /* end H5EA__cache_dblk_page_deserialize() */
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5EA__cache_dblk_page_flush
+ * Function:    H5EA__cache_dblk_page_image_len
  *
- * Purpose:	Flushes a dirty extensible array data block page to disk.
+ * Purpose:     Compute the size of the data structure on disk.
  *
- * Return:	Non-negative on success/Negative on failure
+ * Return:      Non-negative on success/Negative on failure
  *
- * Programmer:	Quincey Koziol
- *		koziol@hdfgroup.org
- *		Nov 20 2008
+ * Programmer:  Quincey Koziol
+ *              koziol@hdfgroup.org
+ *              July 17, 2013
  *
  *-------------------------------------------------------------------------
  */
-BEGIN_FUNC(STATIC, ERR,
-herr_t, SUCCEED, FAIL,
-H5EA__cache_dblk_page_flush(H5F_t *f, hid_t dxpl_id, hbool_t destroy, haddr_t addr,
-    H5EA_dblk_page_t *dblk_page, unsigned H5_ATTR_UNUSED * flags_ptr))
+BEGIN_FUNC(STATIC, NOERR,
+herr_t, SUCCEED, -,
+H5EA__cache_dblk_page_image_len(const void *_thing, size_t *image_len,
+    hbool_t H5_ATTR_UNUSED *compressed_ptr, size_t H5_ATTR_UNUSED *compressed_image_len_ptr))
 
     /* Local variables */
-    H5WB_t *wb = NULL;                  /* Wrapped buffer for serializing data */
-    uint8_t ser_buf[H5EA_DBLK_PAGE_BUF_SIZE]; /* Serialization buffer */
+    const H5EA_dblk_page_t *dblk_page = (const H5EA_dblk_page_t *)_thing;      /* Pointer to the object */
 
-    /* Sanity check */
-    HDassert(f);
-    HDassert(H5F_addr_defined(addr));
+    /* Check arguments */
     HDassert(dblk_page);
-    HDassert(dblk_page->hdr);
-
-    if(dblk_page->cache_info.is_dirty) {
-        uint8_t	*buf;           /* Temporary raw data buffer */
-        uint8_t *p;             /* Pointer into raw data buffer */
-        size_t	size;           /* Index block size on disk */
-        uint32_t metadata_chksum; /* Computed metadata checksum value */
-
-        /* Wrap the local buffer for serialized info */
-        if(NULL == (wb = H5WB_wrap(ser_buf, sizeof(ser_buf))))
-            H5E_THROW(H5E_CANTINIT, "can't wrap buffer")
-
-        /* Compute the size of the data block on disk */
-        size = dblk_page->size;
-
-        /* Get a pointer to a buffer that's large enough for serialized info */
-        if(NULL == (buf = (uint8_t *)H5WB_actual(wb, size)))
-            H5E_THROW(H5E_CANTGET, "can't get actual buffer")
-
-        /* Get temporary pointer to serialized info */
-        p = buf;
-
-        /* Internal information */
-
-        /* Encode elements in data block page */
-
-        /* Convert from native elements in memory into raw elements on disk */
-        if((dblk_page->hdr->cparam.cls->encode)(p, dblk_page->elmts, dblk_page->hdr->dblk_page_nelmts, dblk_page->hdr->cb_ctx) < 0)
-            H5E_THROW(H5E_CANTENCODE, "can't encode extensible array data elements")
-        p += (dblk_page->hdr->dblk_page_nelmts * dblk_page->hdr->cparam.raw_elmt_size);
-
-        /* Compute metadata checksum */
-        metadata_chksum = H5_checksum_metadata(buf, (size_t)(p - buf), 0);
-
-        /* Metadata checksum */
-        UINT32ENCODE(p, metadata_chksum);
-
-	/* Write the data block */
-        HDassert((size_t)(p - buf) == size);
-	if(H5F_block_write(f, H5FD_MEM_EARRAY_DBLK_PAGE, addr, size, dxpl_id, buf) < 0)
-            H5E_THROW(H5E_WRITEERROR, "unable to save extensible array data block page to disk")
-
-	dblk_page->cache_info.is_dirty = FALSE;
-    } /* end if */
+    HDassert(image_len);
 
-    if(destroy)
-        if(H5EA__cache_dblk_page_dest(f, dblk_page) < 0)
-            H5E_THROW(H5E_CANTFREE, "unable to destroy extensible array data block page")
-
-CATCH
-
-    /* Release resources */
-    if(wb && H5WB_unwrap(wb) < 0)
-	H5E_THROW(H5E_CLOSEERROR, "can't close wrapped buffer")
+    /* Set the image length size */
+    *image_len = dblk_page->size;
 
-END_FUNC(STATIC)   /* end H5EA__cache_dblk_page_flush() */
+END_FUNC(STATIC)   /* end H5EA__cache_dblk_page_image_len() */
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5EA__cache_dblk_page_clear
+ * Function:	H5EA__cache_dblk_page_serialize
  *
- * Purpose:	Mark a extensible array data block page in memory as non-dirty.
+ * Purpose:	Flushes a dirty object to disk.
  *
  * Return:	Non-negative on success/Negative on failure
  *
  * Programmer:	Quincey Koziol
- *		koziol@hdfgroup.org
- *		Nov 20 2008
+ *              koziol@hdfgroup.org
+ *              July 17, 2013
  *
  *-------------------------------------------------------------------------
  */
 BEGIN_FUNC(STATIC, ERR,
 herr_t, SUCCEED, FAIL,
-H5EA__cache_dblk_page_clear(H5F_t *f, H5EA_dblk_page_t *dblk_page, hbool_t destroy))
+H5EA__cache_dblk_page_serialize(const H5F_t *f, void *_image, size_t H5_ATTR_UNUSED len,
+    void *_thing))
 
-    /* Sanity check */
+    /* Local variables */
+    H5EA_dblk_page_t *dblk_page = (H5EA_dblk_page_t *)_thing;      /* Pointer to the object to serialize */
+    uint8_t *image = (uint8_t *)_image;         /* Pointer into raw data buffer */
+    uint32_t metadata_chksum;   /* Computed metadata checksum value */
+
+    /* Check arguments */
+    HDassert(f);
+    HDassert(image);
     HDassert(dblk_page);
+    HDassert(dblk_page->hdr);
+
+    /* Internal information */
 
-    /* Reset the dirty flag */
-    dblk_page->cache_info.is_dirty = FALSE;
+    /* Encode elements in data block page */
 
-    if(destroy)
-        if(H5EA__cache_dblk_page_dest(f, dblk_page) < 0)
-            H5E_THROW(H5E_CANTFREE, "unable to destroy extensible array data block page")
+    /* Convert from native elements in memory into raw elements on disk */
+    if((dblk_page->hdr->cparam.cls->encode)(image, dblk_page->elmts, dblk_page->hdr->dblk_page_nelmts, dblk_page->hdr->cb_ctx) < 0)
+        H5E_THROW(H5E_CANTENCODE, "can't encode extensible array data elements")
+    image += (dblk_page->hdr->dblk_page_nelmts * dblk_page->hdr->cparam.raw_elmt_size);
+
+    /* Compute metadata checksum */
+    metadata_chksum = H5_checksum_metadata(_image, (size_t)(image - (uint8_t *)_image), 0);
+
+    /* Metadata checksum */
+    UINT32ENCODE(image, metadata_chksum);
+
+    /* Sanity check */
+    HDassert((size_t)(image - (uint8_t *)_image) <= len);
 
 CATCH
 
-END_FUNC(STATIC)   /* end H5EA__cache_dblk_page_clear() */
+END_FUNC(STATIC)   /* end H5EA__cache_dblk_page_serialize() */
 
 
 /*-------------------------------------------------------------------------
@@ -1976,7 +1838,10 @@ END_FUNC(STATIC)   /* end H5EA__cache_dblk_page_clear() */
  */
 BEGIN_FUNC(STATIC, ERR,
 herr_t, SUCCEED, FAIL,
-H5EA__cache_dblk_page_notify(H5AC_notify_action_t action, H5EA_dblk_page_t *dblk_page))
+H5EA__cache_dblk_page_notify(H5AC_notify_action_t action, void *_thing))
+
+    /* Local variables */
+    H5EA_dblk_page_t *dblk_page = (H5EA_dblk_page_t *)_thing;      /* Pointer to the object */
 
     /* Sanity check */
     HDassert(dblk_page);
@@ -1984,11 +1849,16 @@ H5EA__cache_dblk_page_notify(H5AC_notify_action_t action, H5EA_dblk_page_t *dblk
     /* Determine which action to take */
     switch(action) {
         case H5AC_NOTIFY_ACTION_AFTER_INSERT:
+        case H5AC_NOTIFY_ACTION_AFTER_LOAD:
             /* Create flush dependency on parent */
             if(H5EA__create_flush_depend((H5AC_info_t *)dblk_page->parent, (H5AC_info_t *)dblk_page) < 0)
                 H5E_THROW(H5E_CANTDEPEND, "unable to create flush dependency between data block page and parent, address = %llu", (unsigned long long)dblk_page->addr)
             break;
 
+	case H5AC_NOTIFY_ACTION_AFTER_FLUSH:
+	    /* do nothing */
+	    break;
+
         case H5AC_NOTIFY_ACTION_BEFORE_EVICT:
             /* Destroy flush dependency on parent */
             if(H5EA__destroy_flush_depend((H5AC_info_t *)dblk_page->parent, (H5AC_info_t *)dblk_page) < 0)
@@ -2005,70 +1875,31 @@ END_FUNC(STATIC)   /* end H5EA__cache_dblk_page_notify() */
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5EA__cache_dblk_page_size
+ * Function:	H5EA__cache_dblk_page_free_icr
  *
- * Purpose:	Compute the size in bytes of a extensible array data block page
- *		on disk, and return it in *size_ptr.  On failure,
- *		the value of *size_ptr is undefined.
+ * Purpose:	Destroy/release an "in core representation" of a data
+ *              structure
  *
  * Return:	Non-negative on success/Negative on failure
  *
  * Programmer:	Quincey Koziol
- *		koziol@hdfgroup.org
- *		Nov 20 2008
+ *              koziol@hdfgroup.org
+ *              July 17, 2013
  *
  *-------------------------------------------------------------------------
  */
-/* ARGSUSED */
-BEGIN_FUNC(STATIC, NOERR,
-herr_t, SUCCEED, -,
-H5EA__cache_dblk_page_size(const H5F_t H5_ATTR_UNUSED *f, const H5EA_dblk_page_t *dblk_page,
-    size_t *size_ptr))
-
-    /* Sanity check */
-    HDassert(f);
-    HDassert(dblk_page);
-    HDassert(size_ptr);
-
-    /* Set size value */
-    *size_ptr = dblk_page->size;
-
-END_FUNC(STATIC)   /* end H5EA__cache_dblk_page_size() */
-
-
-/*-------------------------------------------------------------------------
- * Function:	H5EA__cache_dblk_page_dest
- *
- * Purpose:	Destroys an extensible array data block page in memory.
- *
- * Note:	Does _not_ free the space for the page on disk, that is
- *              handled through the data block that "owns" the page.
- *
- * Return:	Non-negative on success/Negative on failure
- *
- * Programmer:	Quincey Koziol
- *		koziol@hdfgroup.org
- *		Nov 20 2008
- *
- *-------------------------------------------------------------------------
- */
-/* ARGSUSED */
 BEGIN_FUNC(STATIC, ERR,
 herr_t, SUCCEED, FAIL,
-H5EA__cache_dblk_page_dest(H5F_t H5_ATTR_UNUSED *f, H5EA_dblk_page_t *dblk_page))
-
-    /* Sanity check */
-    HDassert(f);
-    HDassert(dblk_page);
+H5EA__cache_dblk_page_free_icr(void *thing))
 
-    /* Verify that data block page is clean */
-    HDassert(dblk_page->cache_info.is_dirty == FALSE);
+    /* Check arguments */
+    HDassert(thing);
 
-    /* Release the data block page */
-    if(H5EA__dblk_page_dest(dblk_page) < 0)
+    /* Release the extensible array data block page */
+    if(H5EA__dblk_page_dest((H5EA_dblk_page_t *)thing) < 0)
         H5E_THROW(H5E_CANTFREE, "can't free extensible array data block page")
 
 CATCH
 
-END_FUNC(STATIC)   /* end H5EA__cache_dblk_page_dest() */
+END_FUNC(STATIC)   /* end H5EA__cache_dblk_page_free_icr() */
 
diff --git a/src/H5EAdbg.c b/src/H5EAdbg.c
index ff55722..9c3ce6d 100644
--- a/src/H5EAdbg.c
+++ b/src/H5EAdbg.c
@@ -119,7 +119,7 @@ H5EA__hdr_debug(H5F_t *f, hid_t dxpl_id, haddr_t addr, FILE *stream, int indent,
     } /* end if */
 
     /* Load the extensible array header */
-    if(NULL == (hdr = H5EA__hdr_protect(f, dxpl_id, addr, dbg_ctx, H5AC_READ)))
+    if(NULL == (hdr = H5EA__hdr_protect(f, dxpl_id, addr, dbg_ctx, H5AC__READ_ONLY_FLAG)))
 	H5E_THROW(H5E_CANTPROTECT, "unable to load extensible array header")
 
     /* Print opening message */
@@ -218,14 +218,14 @@ H5EA__iblock_debug(H5F_t *f, hid_t dxpl_id, haddr_t H5_ATTR_UNUSED addr, FILE *s
     } /* end if */
 
     /* Load the extensible array header */
-    if(NULL == (hdr = H5EA__hdr_protect(f, dxpl_id, hdr_addr, dbg_ctx, H5AC_READ)))
+    if(NULL == (hdr = H5EA__hdr_protect(f, dxpl_id, hdr_addr, dbg_ctx, H5AC__READ_ONLY_FLAG)))
 	H5E_THROW(H5E_CANTPROTECT, "unable to load extensible array header")
 
     /* Sanity check */
     HDassert(H5F_addr_eq(hdr->idx_blk_addr, addr));
 
     /* Protect index block */
-    if(NULL == (iblock = H5EA__iblock_protect(hdr, dxpl_id, H5AC_READ)))
+    if(NULL == (iblock = H5EA__iblock_protect(hdr, dxpl_id, H5AC__READ_ONLY_FLAG)))
         H5E_THROW(H5E_CANTPROTECT, "unable to protect extensible array index block, address = %llu", (unsigned long long)hdr->idx_blk_addr)
 
     /* Print opening message */
@@ -343,12 +343,12 @@ H5EA__sblock_debug(H5F_t *f, hid_t dxpl_id, haddr_t addr, FILE *stream, int inde
     } /* end if */
 
     /* Load the extensible array header */
-    if(NULL == (hdr = H5EA__hdr_protect(f, dxpl_id, hdr_addr, dbg_ctx, H5AC_READ)))
+    if(NULL == (hdr = H5EA__hdr_protect(f, dxpl_id, hdr_addr, dbg_ctx, H5AC__READ_ONLY_FLAG)))
 	H5E_THROW(H5E_CANTPROTECT, "unable to load extensible array header")
 
     /* Protect super block */
     /* (Note: setting parent of super block to 'hdr' for this operation should be OK -QAK) */
-    if(NULL == (sblock = H5EA__sblock_protect(hdr, dxpl_id, (H5EA_iblock_t *)hdr, addr, sblk_idx, H5AC_READ)))
+    if(NULL == (sblock = H5EA__sblock_protect(hdr, dxpl_id, (H5EA_iblock_t *)hdr, addr, sblk_idx, H5AC__READ_ONLY_FLAG)))
         H5E_THROW(H5E_CANTPROTECT, "unable to protect extensible array super block, address = %llu", (unsigned long long)addr)
 
     /* Print opening message */
@@ -437,12 +437,12 @@ H5EA__dblock_debug(H5F_t *f, hid_t dxpl_id, haddr_t addr, FILE *stream, int inde
     } /* end if */
 
     /* Load the extensible array header */
-    if(NULL == (hdr = H5EA__hdr_protect(f, dxpl_id, hdr_addr, dbg_ctx, H5AC_READ)))
+    if(NULL == (hdr = H5EA__hdr_protect(f, dxpl_id, hdr_addr, dbg_ctx, H5AC__READ_ONLY_FLAG)))
 	H5E_THROW(H5E_CANTPROTECT, "unable to load extensible array header")
 
     /* Protect data block */
     /* (Note: setting parent of data block to 'hdr' for this operation should be OK -QAK) */
-    if(NULL == (dblock = H5EA__dblock_protect(hdr, dxpl_id, hdr, addr, dblk_nelmts, H5AC_READ)))
+    if(NULL == (dblock = H5EA__dblock_protect(hdr, dxpl_id, hdr, addr, dblk_nelmts, H5AC__READ_ONLY_FLAG)))
         H5E_THROW(H5E_CANTPROTECT, "unable to protect extensible array data block, address = %llu", (unsigned long long)addr)
 
     /* Print opening message */
diff --git a/src/H5EAdblkpage.c b/src/H5EAdblkpage.c
index 37fd68b..5d188c2 100644
--- a/src/H5EAdblkpage.c
+++ b/src/H5EAdblkpage.c
@@ -210,7 +210,7 @@ END_FUNC(PKG)   /* end H5EA__dblk_page_create() */
 BEGIN_FUNC(PKG, ERR,
 H5EA_dblk_page_t *, NULL, NULL,
 H5EA__dblk_page_protect(H5EA_hdr_t *hdr, hid_t dxpl_id, H5EA_sblock_t *parent,
-    haddr_t dblk_page_addr, H5AC_protect_t rw))
+    haddr_t dblk_page_addr, unsigned flags))
 
     /* Local variables */
     H5EA_dblk_page_cache_ud_t udata;      /* Information needed for loading data block page */
@@ -223,12 +223,16 @@ HDfprintf(stderr, "%s: Called\n", FUNC);
     HDassert(hdr);
     HDassert(H5F_addr_defined(dblk_page_addr));
 
+    /* only the H5AC__READ_ONLY_FLAG may be set */
+    HDassert((flags & (unsigned)(~H5AC__READ_ONLY_FLAG)) == 0);
+
     /* Set up user data */
     udata.hdr = hdr;
     udata.parent = parent;
+    udata.dblk_page_addr = dblk_page_addr;
 
     /* Protect the data block page */
-    if(NULL == (ret_value = (H5EA_dblk_page_t *)H5AC_protect(hdr->f, dxpl_id, H5AC_EARRAY_DBLK_PAGE, dblk_page_addr, &udata, rw)))
+    if(NULL == (ret_value = (H5EA_dblk_page_t *)H5AC_protect(hdr->f, dxpl_id, H5AC_EARRAY_DBLK_PAGE, dblk_page_addr, &udata, flags)))
         H5E_THROW(H5E_CANTPROTECT, "unable to protect extensible array data block page, address = %llu", (unsigned long long)dblk_page_addr)
 
 CATCH
diff --git a/src/H5EAdblock.c b/src/H5EAdblock.c
index dd1e7b0..24be87a 100644
--- a/src/H5EAdblock.c
+++ b/src/H5EAdblock.c
@@ -304,7 +304,7 @@ END_FUNC(PKG)   /* end H5EA__dblock_sblk_idx() */
 BEGIN_FUNC(PKG, ERR,
 H5EA_dblock_t *, NULL, NULL,
 H5EA__dblock_protect(H5EA_hdr_t *hdr, hid_t dxpl_id, void *parent,
-    haddr_t dblk_addr, size_t dblk_nelmts, H5AC_protect_t rw))
+    haddr_t dblk_addr, size_t dblk_nelmts, unsigned flags))
 
     /* Local variables */
     H5EA_dblock_cache_ud_t udata;      /* Information needed for loading data block */
@@ -318,13 +318,17 @@ HDfprintf(stderr, "%s: Called\n", FUNC);
     HDassert(H5F_addr_defined(dblk_addr));
     HDassert(dblk_nelmts);
 
+    /* only the H5AC__READ_ONLY_FLAG may be set */
+    HDassert((flags & (unsigned)(~H5AC__READ_ONLY_FLAG)) == 0);
+
     /* Set up user data */
     udata.hdr = hdr;
     udata.parent = parent;
     udata.nelmts = dblk_nelmts;
+    udata.dblk_addr = dblk_addr;
 
     /* Protect the data block */
-    if(NULL == (ret_value = (H5EA_dblock_t *)H5AC_protect(hdr->f, dxpl_id, H5AC_EARRAY_DBLOCK, dblk_addr, &udata, rw)))
+    if(NULL == (ret_value = (H5EA_dblock_t *)H5AC_protect(hdr->f, dxpl_id, H5AC_EARRAY_DBLOCK, dblk_addr, &udata, flags)))
         H5E_THROW(H5E_CANTPROTECT, "unable to protect extensible array data block, address = %llu", (unsigned long long)dblk_addr)
 
 CATCH
@@ -399,7 +403,7 @@ HDfprintf(stderr, "%s: Called\n", FUNC);
     HDassert(dblk_nelmts > 0);
 
     /* Protect data block */
-    if(NULL == (dblock = H5EA__dblock_protect(hdr, dxpl_id, parent, dblk_addr, dblk_nelmts, H5AC_WRITE)))
+    if(NULL == (dblock = H5EA__dblock_protect(hdr, dxpl_id, parent, dblk_addr, dblk_nelmts, H5AC__NO_FLAGS_SET)))
         H5E_THROW(H5E_CANTPROTECT, "unable to protect extensible array data block, address = %llu", (unsigned long long)dblk_addr)
 
     /* Check if this is a paged data block */
diff --git a/src/H5EAhdr.c b/src/H5EAhdr.c
index 76ea6d8..e30bbac 100644
--- a/src/H5EAhdr.c
+++ b/src/H5EAhdr.c
@@ -627,16 +627,25 @@ END_FUNC(PKG)   /* end H5EA__hdr_modified() */
 BEGIN_FUNC(PKG, ERR,
 H5EA_hdr_t *, NULL, NULL,
 H5EA__hdr_protect(H5F_t *f, hid_t dxpl_id, haddr_t ea_addr, void *ctx_udata,
-    H5AC_protect_t rw))
+    unsigned flags))
 
     /* Local variables */
+    H5EA_hdr_cache_ud_t udata;  /* User data for cache callbacks */
 
     /* Sanity check */
     HDassert(f);
     HDassert(H5F_addr_defined(ea_addr));
 
+    /* only the H5AC__READ_ONLY_FLAG may appear in flags */
+    HDassert((flags & (unsigned)(~H5AC__READ_ONLY_FLAG)) == 0);
+
+    /* Set up user data for cache callbacks */
+    udata.f = f;
+    udata.addr = ea_addr;
+    udata.ctx_udata = ctx_udata;
+
     /* Protect the header */
-    if(NULL == (ret_value = (H5EA_hdr_t *)H5AC_protect(f, dxpl_id, H5AC_EARRAY_HDR, ea_addr, ctx_udata, rw)))
+    if(NULL == (ret_value = (H5EA_hdr_t *)H5AC_protect(f, dxpl_id, H5AC_EARRAY_HDR, ea_addr, &udata, flags)))
         H5E_THROW(H5E_CANTPROTECT, "unable to protect extensible array header, address = %llu", (unsigned long long)ea_addr)
 
 CATCH
diff --git a/src/H5EAiblock.c b/src/H5EAiblock.c
index 3c2894a..364b443 100644
--- a/src/H5EAiblock.c
+++ b/src/H5EAiblock.c
@@ -279,7 +279,7 @@ END_FUNC(PKG)   /* end H5EA__iblock_create() */
  */
 BEGIN_FUNC(PKG, ERR,
 H5EA_iblock_t *, NULL, NULL,
-H5EA__iblock_protect(H5EA_hdr_t *hdr, hid_t dxpl_id, H5AC_protect_t rw))
+H5EA__iblock_protect(H5EA_hdr_t *hdr, hid_t dxpl_id, unsigned flags))
 
 #ifdef QAK
 HDfprintf(stderr, "%s: Called\n", FUNC);
@@ -288,8 +288,11 @@ HDfprintf(stderr, "%s: Called\n", FUNC);
     /* Sanity check */
     HDassert(hdr);
 
+    /* only the H5AC__READ_ONLY_FLAG may be set */
+    HDassert((flags & (unsigned)(~H5AC__READ_ONLY_FLAG)) == 0);
+
     /* Protect the index block */
-    if(NULL == (ret_value = (H5EA_iblock_t *)H5AC_protect(hdr->f, dxpl_id, H5AC_EARRAY_IBLOCK, hdr->idx_blk_addr, hdr, rw)))
+    if(NULL == (ret_value = (H5EA_iblock_t *)H5AC_protect(hdr->f, dxpl_id, H5AC_EARRAY_IBLOCK, hdr->idx_blk_addr, hdr, flags)))
         H5E_THROW(H5E_CANTPROTECT, "unable to protect extensible array index block, address = %llu", (unsigned long long)hdr->idx_blk_addr)
 
 CATCH
@@ -361,7 +364,7 @@ HDfprintf(stderr, "%s: Called\n", FUNC);
     HDassert(H5F_addr_defined(hdr->idx_blk_addr));
 
     /* Protect index block */
-    if(NULL == (iblock = H5EA__iblock_protect(hdr, dxpl_id, H5AC_WRITE)))
+    if(NULL == (iblock = H5EA__iblock_protect(hdr, dxpl_id, H5AC__NO_FLAGS_SET)))
         H5E_THROW(H5E_CANTPROTECT, "unable to protect extensible array index block, address = %llu", (unsigned long long)hdr->idx_blk_addr)
 
     /* Check for index block having data block pointers */
@@ -436,7 +439,6 @@ H5EA__iblock_dest(H5EA_iblock_t *iblock))
 
     /* Sanity check */
     HDassert(iblock);
-    HDassert(iblock->rc == 0);
 
     /* Check if shared header field has been initialized */
     if(iblock->hdr) {
diff --git a/src/H5EApkg.h b/src/H5EApkg.h
index 5382eac..d328c05 100644
--- a/src/H5EApkg.h
+++ b/src/H5EApkg.h
@@ -229,7 +229,6 @@ typedef struct H5EA_iblock_t {
     haddr_t     *sblk_addrs;    /* Buffer for addresses of super blocks in index block */
 
     /* Internal array information (not stored) */
-    size_t      rc;             /* Reference count of objects using this block */
     H5EA_hdr_t	*hdr;	        /* Shared array header info	              */
     haddr_t     addr;           /* Address of this index block on disk	      */
     size_t      size;           /* Size of index block on disk		      */
@@ -251,7 +250,6 @@ typedef struct H5EA_sblock_t {
     uint8_t     *page_init;     /* Bitmap of whether a data block page is initialized */
 
     /* Internal array information (not stored) */
-    size_t      rc;             /* Reference count of objects using this block */
     H5EA_hdr_t	*hdr;	        /* Shared array header info	              */
     H5EA_iblock_t *parent;	/* Parent object for super block (index block) */
     haddr_t     addr;           /* Address of this index block on disk	      */
@@ -312,11 +310,19 @@ struct H5EA_t {
 
 /* Metadata cache callback user data types */
 
+/* Info needed for loading header */
+typedef struct H5EA_hdr_cache_ud_t {
+    H5F_t      *f;              /* Pointer to file for extensible array */
+    haddr_t    addr;            /* Address of header on disk */
+    void       *ctx_udata;      /* User context for class */
+} H5EA_hdr_cache_ud_t;
+
 /* Info needed for loading super block */
 typedef struct H5EA_sblock_cache_ud_t {
     H5EA_hdr_t    *hdr;         /* Shared extensible array information */
     H5EA_iblock_t *parent;      /* Pointer to parent object for super block (index block) */
     unsigned sblk_idx;          /* Index of super block */
+    haddr_t sblk_addr;          /* Address of super block */
 } H5EA_sblock_cache_ud_t;
 
 /* Info needed for loading data block */
@@ -324,12 +330,14 @@ typedef struct H5EA_dblock_cache_ud_t {
     H5EA_hdr_t    *hdr;         /* Shared extensible array information */
     void *parent;               /* Pointer to parent object for data block (index or super block) */
     size_t nelmts;              /* Number of elements in data block */
+    haddr_t dblk_addr;          /* Address of data block */
 } H5EA_dblock_cache_ud_t;
 
 /* Info needed for loading data block page */
 typedef struct H5EA_dblk_page_cache_ud_t {
     H5EA_hdr_t    *hdr;         /* Shared extensible array information */
     H5EA_sblock_t *parent;      /* Pointer to parent object for data block page (super block) */
+    haddr_t dblk_page_addr;     /* Address of data block page */
 } H5EA_dblk_page_cache_ud_t;
 
 #ifdef H5EA_TESTING
@@ -388,7 +396,7 @@ H5_DLL herr_t H5EA__hdr_fuse_incr(H5EA_hdr_t *hdr);
 H5_DLL size_t H5EA__hdr_fuse_decr(H5EA_hdr_t *hdr);
 H5_DLL herr_t H5EA__hdr_modified(H5EA_hdr_t *hdr);
 H5_DLL H5EA_hdr_t *H5EA__hdr_protect(H5F_t *f, hid_t dxpl_id, haddr_t ea_addr,
-    void *ctx_udata, H5AC_protect_t rw);
+    void *ctx_udata, unsigned flags);
 H5_DLL herr_t H5EA__hdr_unprotect(H5EA_hdr_t *hdr, hid_t dxpl_id, unsigned cache_flags);
 H5_DLL herr_t H5EA__hdr_delete(H5EA_hdr_t *hdr, hid_t dxpl_id);
 H5_DLL herr_t H5EA__hdr_dest(H5EA_hdr_t *hdr);
@@ -398,7 +406,7 @@ H5_DLL H5EA_iblock_t *H5EA__iblock_alloc(H5EA_hdr_t *hdr);
 H5_DLL haddr_t H5EA__iblock_create(H5EA_hdr_t *hdr, hid_t dxpl_id,
     hbool_t *stats_changed);
 H5_DLL H5EA_iblock_t *H5EA__iblock_protect(H5EA_hdr_t *hdr, hid_t dxpl_id,
-    H5AC_protect_t rw);
+    unsigned flags);
 H5_DLL herr_t H5EA__iblock_unprotect(H5EA_iblock_t *iblock, hid_t dxpl_id,
     unsigned cache_flags);
 H5_DLL herr_t H5EA__iblock_delete(H5EA_hdr_t *hdr, hid_t dxpl_id);
@@ -410,7 +418,8 @@ H5_DLL H5EA_sblock_t *H5EA__sblock_alloc(H5EA_hdr_t *hdr, H5EA_iblock_t *parent,
 H5_DLL haddr_t H5EA__sblock_create(H5EA_hdr_t *hdr, hid_t dxpl_id,
     H5EA_iblock_t *parent, hbool_t *stats_changed, unsigned sblk_idx);
 H5_DLL H5EA_sblock_t *H5EA__sblock_protect(H5EA_hdr_t *hdr, hid_t dxpl_id,
-    H5EA_iblock_t *parent, haddr_t sblk_addr, unsigned sblk_idx, H5AC_protect_t rw);
+    H5EA_iblock_t *parent, haddr_t sblk_addr, unsigned sblk_idx, 
+    unsigned flags);
 H5_DLL herr_t H5EA__sblock_unprotect(H5EA_sblock_t *sblock, hid_t dxpl_id,
     unsigned cache_flags);
 H5_DLL herr_t H5EA__sblock_delete(H5EA_hdr_t *hdr, hid_t dxpl_id,
@@ -424,7 +433,7 @@ H5_DLL haddr_t H5EA__dblock_create(H5EA_hdr_t *hdr, hid_t dxpl_id, void *parent,
     hbool_t *stats_changed, hsize_t dblk_off, size_t nelmts);
 H5_DLL unsigned H5EA__dblock_sblk_idx(const H5EA_hdr_t *hdr, hsize_t idx);
 H5_DLL H5EA_dblock_t *H5EA__dblock_protect(H5EA_hdr_t *hdr, hid_t dxpl_id,
-    void *parent, haddr_t dblk_addr, size_t dblk_nelmts, H5AC_protect_t rw);
+    void *parent, haddr_t dblk_addr, size_t dblk_nelmts, unsigned flags);
 H5_DLL herr_t H5EA__dblock_unprotect(H5EA_dblock_t *dblock, hid_t dxpl_id,
     unsigned cache_flags);
 H5_DLL herr_t H5EA__dblock_delete(H5EA_hdr_t *hdr, hid_t dxpl_id, void *parent,
@@ -436,7 +445,7 @@ H5_DLL H5EA_dblk_page_t *H5EA__dblk_page_alloc(H5EA_hdr_t *hdr, H5EA_sblock_t *p
 H5_DLL herr_t H5EA__dblk_page_create(H5EA_hdr_t *hdr, hid_t dxpl_id,
     H5EA_sblock_t *parent, haddr_t addr);
 H5_DLL H5EA_dblk_page_t *H5EA__dblk_page_protect(H5EA_hdr_t *hdr, hid_t dxpl_id,
-    H5EA_sblock_t *parent, haddr_t dblk_page_addr, H5AC_protect_t rw);
+    H5EA_sblock_t *parent, haddr_t dblk_page_addr, unsigned flags);
 H5_DLL herr_t H5EA__dblk_page_unprotect(H5EA_dblk_page_t *dblk_page,
     hid_t dxpl_id, unsigned cache_flags);
 H5_DLL herr_t H5EA__dblk_page_dest(H5EA_dblk_page_t *dblk_page);
diff --git a/src/H5EAsblock.c b/src/H5EAsblock.c
index 1cc8bd9..33f34c9 100644
--- a/src/H5EAsblock.c
+++ b/src/H5EAsblock.c
@@ -276,7 +276,7 @@ END_FUNC(PKG)   /* end H5EA__sblock_create() */
 BEGIN_FUNC(PKG, ERR,
 H5EA_sblock_t *, NULL, NULL,
 H5EA__sblock_protect(H5EA_hdr_t *hdr, hid_t dxpl_id, H5EA_iblock_t *parent,
-    haddr_t sblk_addr, unsigned sblk_idx, H5AC_protect_t rw))
+    haddr_t sblk_addr, unsigned sblk_idx, unsigned flags))
 
     /* Local variables */
     H5EA_sblock_cache_ud_t udata;      /* Information needed for loading super block */
@@ -290,13 +290,17 @@ HDfprintf(stderr, "%s: Called\n", FUNC);
     HDassert(hdr);
     HDassert(H5F_addr_defined(sblk_addr));
 
+    /* only the H5AC__READ_ONLY_FLAG may be set */
+    HDassert((flags & (unsigned)(~H5AC__READ_ONLY_FLAG)) == 0);
+
     /* Set up user data */
     udata.hdr = hdr;
     udata.parent = parent;
     udata.sblk_idx = sblk_idx;
+    udata.sblk_addr = sblk_addr;
 
     /* Protect the super block */
-    if(NULL == (ret_value = (H5EA_sblock_t *)H5AC_protect(hdr->f, dxpl_id, H5AC_EARRAY_SBLOCK, sblk_addr, &udata, rw)))
+    if(NULL == (ret_value = (H5EA_sblock_t *)H5AC_protect(hdr->f, dxpl_id, H5AC_EARRAY_SBLOCK, sblk_addr, &udata, flags)))
         H5E_THROW(H5E_CANTPROTECT, "unable to protect extensible array super block, address = %llu", (unsigned long long)sblk_addr)
 
 CATCH
@@ -370,7 +374,7 @@ HDfprintf(stderr, "%s: Called\n", FUNC);
     HDassert(H5F_addr_defined(sblk_addr));
 
     /* Protect super block */
-    if(NULL == (sblock = H5EA__sblock_protect(hdr, dxpl_id, parent, sblk_addr, sblk_idx, H5AC_WRITE)))
+    if(NULL == (sblock = H5EA__sblock_protect(hdr, dxpl_id, parent, sblk_addr, sblk_idx, H5AC__NO_FLAGS_SET)))
         H5E_THROW(H5E_CANTPROTECT, "unable to protect extensible array super block, address = %llu", (unsigned long long)sblk_addr)
 
     /* Iterate over data blocks */
@@ -412,7 +416,6 @@ H5EA__sblock_dest(H5EA_sblock_t *sblock))
 
     /* Sanity check */
     HDassert(sblock);
-    HDassert(sblock->rc == 0);
 #ifdef QAK
 HDfprintf(stderr, "%s: sblock->hdr->dblk_page_nelmts = %Zu, sblock->ndblks = %Zu, sblock->dblk_nelmts = %Zu\n", FUNC, sblock->hdr->dblk_page_nelmts, sblock->ndblks, sblock->dblk_nelmts);
 #endif /* QAK */
diff --git a/src/H5FA.c b/src/H5FA.c
index 1acb10b..bfb2a00 100644
--- a/src/H5FA.c
+++ b/src/H5FA.c
@@ -141,7 +141,7 @@ HDfprintf(stderr, "%s: Called\n", FUNC);
 	H5E_THROW(H5E_CANTALLOC, "memory allocation failed for fixed array info")
 
     /* Lock the array header into memory */
-    if(NULL == (hdr = H5FA__hdr_protect(f, dxpl_id, fa_addr, ctx_udata, H5AC_WRITE)))
+    if(NULL == (hdr = H5FA__hdr_protect(f, dxpl_id, fa_addr, ctx_udata, H5AC__NO_FLAGS_SET)))
 	H5E_THROW(H5E_CANTPROTECT, "unable to load fixed array header")
 
     /* Point fixed array wrapper at header and bump it's ref count */
@@ -201,7 +201,7 @@ H5FA_open(H5F_t *f, hid_t dxpl_id, haddr_t fa_addr, void *ctx_udata))
 #ifdef H5FA_DEBUG
 HDfprintf(stderr, "%s: fa_addr = %a\n", FUNC, fa_addr);
 #endif /* H5FA_DEBUG */
-    if(NULL == (hdr = H5FA__hdr_protect(f, dxpl_id, fa_addr, ctx_udata, H5AC_READ)))
+    if(NULL == (hdr = H5FA__hdr_protect(f, dxpl_id, fa_addr, ctx_udata, H5AC__READ_ONLY_FLAG)))
         H5E_THROW(H5E_CANTPROTECT, "unable to load fixed array header, address = %llu", (unsigned long long)fa_addr)
 
     /* Check for pending array deletion */
@@ -359,7 +359,7 @@ HDfprintf(stderr, "%s: fixed array data block address not defined!\n", FUNC, idx
     HDassert(idx < hdr->cparam.nelmts);
 
     /* Protect data block */
-    if(NULL == (dblock = H5FA__dblock_protect(hdr, dxpl_id, hdr->dblk_addr, H5AC_WRITE)))
+    if(NULL == (dblock = H5FA__dblock_protect(hdr, dxpl_id, hdr->dblk_addr, H5AC__NO_FLAGS_SET)))
 	H5E_THROW(H5E_CANTPROTECT, "unable to protect fixed array data block, address = %llu", (unsigned long long)hdr->dblk_addr)
 
     /* Check for paging data block */
@@ -400,7 +400,7 @@ HDfprintf(stderr, "%s: fixed array data block address not defined!\n", FUNC, idx
 	} /* end if */
 
         /* Protect the data block page */
-	if(NULL == (dblk_page = H5FA__dblk_page_protect(hdr, dxpl_id, dblk_page_addr, dblk_page_nelmts, H5AC_WRITE)))
+	if(NULL == (dblk_page = H5FA__dblk_page_protect(hdr, dxpl_id, dblk_page_addr, dblk_page_nelmts, H5AC__NO_FLAGS_SET)))
 	    H5E_THROW(H5E_CANTPROTECT, "unable to protect fixed array data block page, address = %llu", (unsigned long long)dblk_page_addr)
 
         /* Set the element in the data block page */
@@ -467,7 +467,7 @@ HDfprintf(stderr, "%s: Index %Hu\n", FUNC, idx);
     else {
         /* Get the data block */
         HDassert(H5F_addr_defined(hdr->dblk_addr));
-        if(NULL == (dblock = H5FA__dblock_protect(hdr, dxpl_id, hdr->dblk_addr, H5AC_READ)))
+        if(NULL == (dblock = H5FA__dblock_protect(hdr, dxpl_id, hdr->dblk_addr, H5AC__READ_ONLY_FLAG)))
             H5E_THROW(H5E_CANTPROTECT, "unable to protect fixed array data block, address = %llu", (unsigned long long)hdr->dblk_addr)
 
         /* Check for paged data block */
@@ -507,7 +507,7 @@ HDfprintf(stderr, "%s: Index %Hu\n", FUNC, idx);
                     dblk_page_nelmts = dblock->dblk_page_nelmts;
 
                 /* Protect the data block page */
-                if(NULL == (dblk_page = H5FA__dblk_page_protect(hdr, dxpl_id, dblk_page_addr, dblk_page_nelmts, H5AC_READ)))
+                if(NULL == (dblk_page = H5FA__dblk_page_protect(hdr, dxpl_id, dblk_page_addr, dblk_page_nelmts, H5AC__READ_ONLY_FLAG)))
                     H5E_THROW(H5E_CANTPROTECT, "unable to protect fixed array data block page, address = %llu", (unsigned long long)dblk_page_addr)
 
                 /* Retrieve element from data block */
@@ -592,7 +592,7 @@ HDfprintf(stderr, "%s: Called\n", FUNC);
 
         /* Lock the array header into memory */
         /* (OK to pass in NULL for callback context, since we know the header must be in the cache) */
-        if(NULL == (hdr = H5FA__hdr_protect(fa->f, dxpl_id, fa_addr, NULL, H5AC_WRITE)))
+        if(NULL == (hdr = H5FA__hdr_protect(fa->f, dxpl_id, fa_addr, NULL, H5AC__NO_FLAGS_SET)))
             H5E_THROW(H5E_CANTLOAD, "unable to load fixed array header")
 
         /* Set the shared array header's file context for this operation */
@@ -655,7 +655,7 @@ H5FA_delete(H5F_t *f, hid_t dxpl_id, haddr_t fa_addr, void *ctx_udata))
 #ifdef H5FA_DEBUG
 HDfprintf(stderr, "%s: fa_addr = %a\n", FUNC, fa_addr);
 #endif /* H5FA_DEBUG */
-    if(NULL == (hdr = H5FA__hdr_protect(f, dxpl_id, fa_addr, ctx_udata, H5AC_WRITE)))
+    if(NULL == (hdr = H5FA__hdr_protect(f, dxpl_id, fa_addr, ctx_udata, H5AC__NO_FLAGS_SET)))
         H5E_THROW(H5E_CANTPROTECT, "unable to protect fixed array header, address = %llu", (unsigned long long)fa_addr)
 
     /* Check for files using shared array header */
diff --git a/src/H5FAcache.c b/src/H5FAcache.c
index 9a1fc57..298eb56 100644
--- a/src/H5FAcache.c
+++ b/src/H5FAcache.c
@@ -55,11 +55,6 @@
 #define H5FA_HDR_VERSION        0               /* Header */
 #define H5FA_DBLOCK_VERSION     0               /* Data block */
 
-/* Size of stack buffer for serialization buffers */
-#define H5FA_HDR_BUF_SIZE       512
-#define H5FA_DBLOCK_BUF_SIZE    512
-#define H5FA_DBLK_PAGE_BUF_SIZE 512
-
 
 /******************/
 /* Local Typedefs */
@@ -76,23 +71,35 @@
 /********************/
 
 /* Metadata cache (H5AC) callbacks */
-static H5FA_hdr_t *H5FA__cache_hdr_load(H5F_t *f, hid_t dxpl_id, haddr_t addr, void *udata);
-static herr_t H5FA__cache_hdr_flush(H5F_t *f, hid_t dxpl_id, hbool_t destroy, haddr_t addr, H5FA_hdr_t *hdr, unsigned * flags_ptr);
-static herr_t H5FA__cache_hdr_clear(H5F_t *f, H5FA_hdr_t *hdr, hbool_t destroy);
-static herr_t H5FA__cache_hdr_size(const H5F_t *f, const H5FA_hdr_t *hdr, size_t *size_ptr);
-static herr_t H5FA__cache_hdr_dest(H5F_t *f, H5FA_hdr_t *hdr);
-
-static H5FA_dblock_t *H5FA__cache_dblock_load(H5F_t *f, hid_t dxpl_id, haddr_t addr, void *udata);
-static herr_t H5FA__cache_dblock_flush(H5F_t *f, hid_t dxpl_id, hbool_t destroy, haddr_t addr, H5FA_dblock_t *dblock, unsigned * flags_ptr);
-static herr_t H5FA__cache_dblock_clear(H5F_t *f, H5FA_dblock_t *dblock, hbool_t destroy);
-static herr_t H5FA__cache_dblock_size(const H5F_t *f, const H5FA_dblock_t *dblock, size_t *size_ptr);
-static herr_t H5FA__cache_dblock_dest(H5F_t *f, H5FA_dblock_t *dblock);
-
-static H5FA_dblk_page_t *H5FA__cache_dblk_page_load(H5F_t *f, hid_t dxpl_id, haddr_t addr, void *udata);
-static herr_t H5FA__cache_dblk_page_flush(H5F_t *f, hid_t dxpl_id, hbool_t destroy, haddr_t addr, H5FA_dblk_page_t *dblk_page, unsigned * flags_ptr);
-static herr_t H5FA__cache_dblk_page_clear(H5F_t *f, H5FA_dblk_page_t *dblk_page, hbool_t destroy);
-static herr_t H5FA__cache_dblk_page_size(const H5F_t *f, const H5FA_dblk_page_t *dblk_page, size_t *size_ptr);
-static herr_t H5FA__cache_dblk_page_dest(H5F_t *f, H5FA_dblk_page_t *dblk_page);
+static herr_t H5FA__cache_hdr_get_load_size(const void *udata, size_t *image_len);
+static void *H5FA__cache_hdr_deserialize(const void *image, size_t len,
+    void *udata, hbool_t *dirty);
+static herr_t H5FA__cache_hdr_image_len(const void *thing, size_t *image_len,
+    hbool_t *compressed_ptr, size_t *compressed_image_len_ptr);
+static herr_t H5FA__cache_hdr_serialize(const H5F_t *f, void *image, size_t len,
+    void *thing);
+static herr_t H5FA__cache_hdr_free_icr(void *thing);
+
+static herr_t H5FA__cache_dblock_get_load_size(const void *udata, size_t *image_len);
+static void *H5FA__cache_dblock_deserialize(const void *image, size_t len,
+    void *udata, hbool_t *dirty);
+static herr_t H5FA__cache_dblock_image_len(const void *thing, 
+    size_t *image_len, hbool_t *compressed_ptr, 
+    size_t *compressed_image_len_ptr);
+static herr_t H5FA__cache_dblock_serialize(const H5F_t *f, void *image, size_t len,
+    void *thing);
+static herr_t H5FA__cache_dblock_free_icr(void *thing);
+static herr_t H5FA__cache_dblock_fsf_size(const void *thing, size_t *fsf_size);
+
+static herr_t H5FA__cache_dblk_page_get_load_size(const void *udata, size_t *image_len);
+static void *H5FA__cache_dblk_page_deserialize(const void *image, size_t len,
+    void *udata, hbool_t *dirty);
+static herr_t H5FA__cache_dblk_page_image_len(const void *thing, 
+    size_t *image_len, hbool_t *compressed_ptr, 
+    size_t *compressed_image_len_ptr);
+static herr_t H5FA__cache_dblk_page_serialize(const H5F_t *f, void *image, size_t len,
+    void *thing);
+static herr_t H5FA__cache_dblk_page_free_icr(void *thing);
 
 
 /*********************/
@@ -101,36 +108,53 @@ static herr_t H5FA__cache_dblk_page_dest(H5F_t *f, H5FA_dblk_page_t *dblk_page);
 
 /* H5FA header inherits cache-like properties from H5AC */
 const H5AC_class_t H5AC_FARRAY_HDR[1] = {{
-    H5AC_FARRAY_HDR_ID,
-    (H5AC_load_func_t)H5FA__cache_hdr_load,
-    (H5AC_flush_func_t)H5FA__cache_hdr_flush,
-    (H5AC_dest_func_t)H5FA__cache_hdr_dest,
-    (H5AC_clear_func_t)H5FA__cache_hdr_clear,
-    (H5AC_notify_func_t)NULL,
-    (H5AC_size_func_t)H5FA__cache_hdr_size,
+    H5AC_FARRAY_HDR_ID,                 /* Metadata client ID */
+    "Fixed-array Header",               /* Metadata client name (for debugging) */
+    H5FD_MEM_FARRAY_HDR,                /* File space memory type for client */
+    H5AC__CLASS_NO_FLAGS_SET,           /* Client class behavior flags */
+    H5FA__cache_hdr_get_load_size,      /* 'get_load_size' callback */
+    H5FA__cache_hdr_deserialize,        /* 'deserialize' callback */
+    H5FA__cache_hdr_image_len,          /* 'image_len' callback */
+    NULL,                               /* 'pre_serialize' callback */
+    H5FA__cache_hdr_serialize,          /* 'serialize' callback */
+    NULL,                               /* 'notify' callback */
+    H5FA__cache_hdr_free_icr,           /* 'free_icr' callback */
+    NULL,				/* 'clear' callback */
+    NULL,                               /* 'fsf_size' callback */
 }};
 
-
 /* H5FA data block inherits cache-like properties from H5AC */
 const H5AC_class_t H5AC_FARRAY_DBLOCK[1] = {{
-    H5AC_FARRAY_DBLOCK_ID,
-    (H5AC_load_func_t)H5FA__cache_dblock_load,
-    (H5AC_flush_func_t)H5FA__cache_dblock_flush,
-    (H5AC_dest_func_t)H5FA__cache_dblock_dest,
-    (H5AC_clear_func_t)H5FA__cache_dblock_clear,
-    (H5AC_notify_func_t)NULL,
-    (H5AC_size_func_t)H5FA__cache_dblock_size,
+    H5AC_FARRAY_DBLOCK_ID,              /* Metadata client ID */
+    "Fixed Array Data Block",           /* Metadata client name (for debugging) */
+    H5FD_MEM_FARRAY_DBLOCK,             /* File space memory type for client */
+    H5AC__CLASS_NO_FLAGS_SET,           /* Client class behavior flags */
+    H5FA__cache_dblock_get_load_size,   /* 'get_load_size' callback */
+    H5FA__cache_dblock_deserialize,     /* 'deserialize' callback */
+    H5FA__cache_dblock_image_len,       /* 'image_len' callback */
+    NULL,                               /* 'pre_serialize' callback */
+    H5FA__cache_dblock_serialize,       /* 'serialize' callback */
+    NULL,                               /* 'notify' callback */
+    H5FA__cache_dblock_free_icr,        /* 'free_icr' callback */
+    NULL,				/* 'clear' callback */
+    H5FA__cache_dblock_fsf_size,        /* 'fsf_size' callback */
 }};
 
 /* H5FA data block page inherits cache-like properties from H5AC */
 const H5AC_class_t H5AC_FARRAY_DBLK_PAGE[1] = {{
-    H5AC_FARRAY_DBLK_PAGE_ID,
-    (H5AC_load_func_t)H5FA__cache_dblk_page_load,
-    (H5AC_flush_func_t)H5FA__cache_dblk_page_flush,
-    (H5AC_dest_func_t)H5FA__cache_dblk_page_dest,
-    (H5AC_clear_func_t)H5FA__cache_dblk_page_clear,
-    (H5AC_notify_func_t)NULL,
-    (H5AC_size_func_t)H5FA__cache_dblk_page_size,
+    H5AC_FARRAY_DBLK_PAGE_ID,           /* Metadata client ID */
+    "Fixed Array Data Block Page",      /* Metadata client name (for debugging) */
+    H5FD_MEM_FARRAY_DBLK_PAGE,          /* File space memory type for client */
+    H5AC__CLASS_NO_FLAGS_SET,           /* Client class behavior flags */
+    H5FA__cache_dblk_page_get_load_size, /* 'get_load_size' callback */
+    H5FA__cache_dblk_page_deserialize,  /* 'deserialize' callback */
+    H5FA__cache_dblk_page_image_len,    /* 'image_len' callback */
+    NULL,                               /* 'pre_serialize' callback */
+    H5FA__cache_dblk_page_serialize,    /* 'serialize' callback */
+    NULL,                               /* 'notify' callback */
+    H5FA__cache_dblk_page_free_icr,     /* 'free_icr' callback */
+    NULL,				/* 'clear' callback */
+    NULL,                               /* 'fsf_size' callback */
 }};
 
 
@@ -146,88 +170,101 @@ const H5AC_class_t H5AC_FARRAY_DBLK_PAGE[1] = {{
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5FA__cache_hdr_load
+ * Function:    H5FA__cache_hdr_get_load_size
+ *
+ * Purpose:     Compute the size of the data structure on disk.
+ *
+ * Return:      Non-negative on success/Negative on failure
+ *
+ * Programmer:  Quincey Koziol
+ *              koziol@hdfgroup.org
+ *              July 31, 2013
+ *
+ *-------------------------------------------------------------------------
+ */
+BEGIN_FUNC(STATIC, NOERR,
+herr_t, SUCCEED, -,
+H5FA__cache_hdr_get_load_size(const void *_udata, size_t *image_len))
+
+    /* Local variables */
+    const H5FA_hdr_cache_ud_t *udata = (const H5FA_hdr_cache_ud_t *)_udata; /* User data for callback */
+
+    /* Check arguments */
+    HDassert(udata);
+    HDassert(udata->f);
+    HDassert(image_len);
+
+    /* Set the image length size */
+    *image_len = (size_t)H5FA_HEADER_SIZE_FILE(udata->f);
+
+END_FUNC(STATIC)   /* end H5FA__cache_hdr_get_load_size() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:	H5FA__cache_hdr_deserialize
  *
- * Purpose:	Loads a fixed array header from the disk.
+ * Purpose:	Loads a data structure from the disk.
  *
- * Return:	Success:	Pointer to a new fixed array
+ * Return:	Success:	Pointer to a new B-tree.
  *		Failure:	NULL
  *
- * Programmer:	Vailin Choi
- *              Thursday, April 30, 2009
+ * Programmer:	Quincey Koziol
+ *              koziol@hdfgroup.org
+ *              August 12, 2013
  *
  *-------------------------------------------------------------------------
  */
 BEGIN_FUNC(STATIC, ERR,
-H5FA_hdr_t *, NULL, NULL,
-H5FA__cache_hdr_load(H5F_t *f, hid_t dxpl_id, haddr_t addr, void *udata))
+void *, NULL, NULL,
+H5FA__cache_hdr_deserialize(const void *_image, size_t len,
+    void *_udata, hbool_t H5_ATTR_UNUSED *dirty))
 
     /* Local variables */
     H5FA_cls_id_t       id;		/* ID of fixed array class, as found in file */
     H5FA_hdr_t		*hdr = NULL;    /* Fixed array info */
-    size_t		size;           /* Header size */
-    H5WB_t              *wb = NULL;     /* Wrapped buffer for header data */
-    uint8_t             hdr_buf[H5FA_HDR_BUF_SIZE]; /* Buffer for header */
-    uint8_t		*buf;           /* Pointer to header buffer */
-    const uint8_t	*p;             /* Pointer into raw data buffer */
+    H5FA_hdr_cache_ud_t *udata = (H5FA_hdr_cache_ud_t *)_udata;
+    const uint8_t	*image = (const uint8_t *)_image;       /* Pointer into raw data buffer */
     uint32_t            stored_chksum;  /* Stored metadata checksum value */
     uint32_t            computed_chksum; /* Computed metadata checksum value */
 
     /* Check arguments */
-    HDassert(f);
-    HDassert(H5F_addr_defined(addr));
+    HDassert(udata);
+    HDassert(udata->f);
+    HDassert(H5F_addr_defined(udata->addr));
 
     /* Allocate space for the fixed array data structure */
-    if(NULL == (hdr = H5FA__hdr_alloc(f)))
+    if(NULL == (hdr = H5FA__hdr_alloc(udata->f)))
 	H5E_THROW(H5E_CANTALLOC, "memory allocation failed for fixed array shared header")
 
     /* Set the fixed array header's address */
-    hdr->addr = addr;
-
-    /* Wrap the local buffer for serialized info */
-    if(NULL == (wb = H5WB_wrap(hdr_buf, sizeof(hdr_buf))))
-	H5E_THROW(H5E_CANTINIT, "can't wrap buffer")
-
-    /* Compute the 'base' size of the fixed array header on disk */
-    size = H5FA_HEADER_SIZE_HDR(hdr);
-
-    /* Get a pointer to a buffer that's large enough for serialized header */
-    if(NULL == (buf = (uint8_t *)H5WB_actual(wb, size)))
-	H5E_THROW(H5E_CANTGET, "can't get actual buffer")
-
-    /* Read header from disk */
-    if(H5F_block_read(f, H5FD_MEM_FARRAY_HDR, addr, size, dxpl_id, buf) < 0)
-	H5E_THROW(H5E_READERROR, "can't read fixed array header")
-
-    /* Get temporary pointer to serialized header */
-    p = buf;
+    hdr->addr = udata->addr;
 
     /* Magic number */
-    if(HDmemcmp(p, H5FA_HDR_MAGIC, (size_t)H5_SIZEOF_MAGIC))
+    if(HDmemcmp(image, H5FA_HDR_MAGIC, (size_t)H5_SIZEOF_MAGIC))
 	H5E_THROW(H5E_BADVALUE, "wrong fixed array header signature")
-    p += H5_SIZEOF_MAGIC;
+    image += H5_SIZEOF_MAGIC;
 
     /* Version */
-    if(*p++ != H5FA_HDR_VERSION)
+    if(*image++ != H5FA_HDR_VERSION)
 	H5E_THROW(H5E_VERSION, "wrong fixed array header version")
 
     /* Fixed array class */
-    id = (H5FA_cls_id_t)*p++;
+    id = (H5FA_cls_id_t)*image++;
     if(id >= H5FA_NUM_CLS_ID)
 	H5E_THROW(H5E_BADTYPE, "incorrect fixed array class")
     hdr->cparam.cls = H5FA_client_class_g[id];
 
     /* General array creation/configuration information */
-    hdr->cparam.raw_elmt_size = *p++;         	   /* Element size in file (in bytes) */
-    hdr->cparam.max_dblk_page_nelmts_bits = *p++;  /* Log2(Max. # of elements in data block page) -
-						      i.e. # of bits needed to store max. # of
-						      elements in data block page. */
+    hdr->cparam.raw_elmt_size = *image++;             /* Element size in file (in bytes) */
+    hdr->cparam.max_dblk_page_nelmts_bits = *image++; /* Log2(Max. # of elements in data block page) -
+						         i.e. # of bits needed to store max. # of
+						         elements in data block page. */
 
     /* Array statistics */
-    H5F_DECODE_LENGTH(f, p, hdr->cparam.nelmts);	/* Number of elements */
+    H5F_DECODE_LENGTH(udata->f, image, hdr->cparam.nelmts);	/* Number of elements */
 
     /* Internal information */
-    H5F_addr_decode(f, &p, &hdr->dblk_addr); 		/* Address of index block */
+    H5F_addr_decode(udata->f, &image, &hdr->dblk_addr); 		/* Address of index block */
 
     /* Check for data block */
     if(H5F_addr_defined(hdr->dblk_addr)) {
@@ -250,26 +287,26 @@ H5FA__cache_hdr_load(H5F_t *f, hid_t dxpl_id, haddr_t addr, void *udata))
 
     /* Sanity check */
     /* (allow for checksum not decoded yet) */
-    HDassert((size_t)(p - buf) == (size - H5FA_SIZEOF_CHKSUM));
+    HDassert((size_t)(image - (const uint8_t *)_image) == (len - H5FA_SIZEOF_CHKSUM));
 
     /* Compute checksum on entire header */
     /* (including the filter information, if present) */
-    computed_chksum = H5_checksum_metadata(buf, (size_t)(p - buf), 0);
+    computed_chksum = H5_checksum_metadata(_image, (size_t)(image - (const uint8_t *)_image), 0);
 
     /* Metadata checksum */
-    UINT32DECODE(p, stored_chksum);
+    UINT32DECODE(image, stored_chksum);
 
     /* Sanity check */
-    HDassert((size_t)(p - buf) == size);
+    HDassert((size_t)(image - (const uint8_t *)_image) == len);
 
     /* Verify checksum */
     if(stored_chksum != computed_chksum)
 	H5E_THROW(H5E_BADVALUE, "incorrect metadata checksum for fixed array header")
 
     /* Finish initializing fixed array header */
-    if(H5FA__hdr_init(hdr, udata) < 0)
+    if(H5FA__hdr_init(hdr, udata->ctx_udata) < 0)
 	H5E_THROW(H5E_CANTINIT, "initialization failed for fixed array header")
-    HDassert(hdr->size == size);
+    HDassert(hdr->size == len);
 
     /* Set return value */
     ret_value = hdr;
@@ -277,326 +314,277 @@ H5FA__cache_hdr_load(H5F_t *f, hid_t dxpl_id, haddr_t addr, void *udata))
 CATCH
 
     /* Release resources */
-    if(wb && H5WB_unwrap(wb) < 0)
-	H5E_THROW(H5E_CLOSEERROR, "can't close wrapped buffer")
     if(!ret_value)
         if(hdr && H5FA__hdr_dest(hdr) < 0)
             H5E_THROW(H5E_CANTFREE, "unable to destroy fixed array header")
 
-END_FUNC(STATIC)   /* end H5FA__cache_hdr_load() */
+END_FUNC(STATIC)   /* end H5FA__cache_hdr_deserialize() */
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5FA__cache_hdr_flush
+ * Function:    H5FA__cache_hdr_image_len
  *
- * Purpose:	Flushes a dirty fixed array header to disk.
+ * Purpose:     Compute the size of the data structure on disk.
  *
- * Return:	Non-negative on success/Negative on failure
+ * Return:      Non-negative on success/Negative on failure
  *
- * Programmer:	Vailin Choi
- *              Thursday, April 30, 2009
+ * Programmer:  Quincey Koziol
+ *              koziol@hdfgroup.org
+ *              August 12, 2013
  *
  *-------------------------------------------------------------------------
  */
-BEGIN_FUNC(STATIC, ERR,
-herr_t, SUCCEED, FAIL,
-H5FA__cache_hdr_flush(H5F_t *f, hid_t dxpl_id, hbool_t destroy, haddr_t addr,
-    H5FA_hdr_t *hdr, unsigned H5_ATTR_UNUSED * flags_ptr))
+BEGIN_FUNC(STATIC, NOERR,
+herr_t, SUCCEED, -,
+H5FA__cache_hdr_image_len(const void *_thing, size_t *image_len,
+    hbool_t H5_ATTR_UNUSED *compressed_ptr, size_t H5_ATTR_UNUSED *compressed_image_len_ptr))
 
-    H5WB_t *wb = NULL;                  /* Wrapped buffer for header data */
-    uint8_t hdr_buf[H5FA_HDR_BUF_SIZE]; /* Buffer for header */
+    /* Local variables */
+    const H5FA_hdr_t *hdr = (const H5FA_hdr_t *)_thing;      /* Pointer to the object */
 
-    /* check arguments */
-    HDassert(f);
-    HDassert(H5F_addr_defined(addr));
+    /* Check arguments */
     HDassert(hdr);
+    HDassert(image_len);
 
-    if(hdr->cache_info.is_dirty) {
-        uint8_t	*buf;           /* Temporary raw data buffer */
-        uint8_t *p;             /* Pointer into raw data buffer */
-        size_t	size;           /* Header size on disk */
-        uint32_t metadata_chksum; /* Computed metadata checksum value */
-
-        /* Wrap the local buffer for serialized header info */
-        if(NULL == (wb = H5WB_wrap(hdr_buf, sizeof(hdr_buf))))
-            H5E_THROW(H5E_CANTINIT, "can't wrap buffer")
-
-        /* Compute the size of the array header on disk */
-        size = hdr->size;
-
-        /* Get a pointer to a buffer that's large enough for serialized header */
-        if(NULL == (buf = (uint8_t *)H5WB_actual(wb, size)))
-            H5E_THROW(H5E_CANTGET, "can't get actual buffer")
-
-        /* Get temporary pointer to serialized header */
-        p = buf;
+    /* Set the image length size */
+    *image_len = hdr->size;
 
-        /* Magic number */
-        HDmemcpy(p, H5FA_HDR_MAGIC, (size_t)H5_SIZEOF_MAGIC);
-        p += H5_SIZEOF_MAGIC;
+END_FUNC(STATIC)   /* end H5FA__cache_hdr_image_len() */
 
-        /* Version # */
-        *p++ = H5FA_HDR_VERSION;
+
+/*-------------------------------------------------------------------------
+ * Function:	H5FA__cache_hdr_serialize
+ *
+ * Purpose:	Flushes a dirty object to disk.
+ *
+ * Return:	Non-negative on success/Negative on failure
+ *
+ * Programmer:	Quincey Koziol
+ *              koziol@hdfgroup.org
+ *              August 12, 2013
+ *
+ *-------------------------------------------------------------------------
+ */
+BEGIN_FUNC(STATIC, NOERR,
+herr_t, SUCCEED, -,
+H5FA__cache_hdr_serialize(const H5F_t *f, void *_image, size_t H5_ATTR_UNUSED len,
+    void *_thing))
 
-        /* Fixed array type */
-        *p++ = hdr->cparam.cls->id;
+    /* Local variables */
+    H5FA_hdr_t *hdr = (H5FA_hdr_t *)_thing;     /* Pointer to the fixed array header */
+    uint8_t *image = (uint8_t *)_image;         /* Pointer into raw data buffer */
+    uint32_t metadata_chksum;   /* Computed metadata checksum value */
 
-        /* General array creation/configuration information */
-        *p++ = hdr->cparam.raw_elmt_size;          /* Element size in file (in bytes) */
-        *p++ = hdr->cparam.max_dblk_page_nelmts_bits;  /* Log2(Max. # of elements in data block page) - i.e. # of bits needed to store max. # of elements in data block page */
+    /* check arguments */
+    HDassert(f);
+    HDassert(image);
+    HDassert(hdr);
 
-        /* Array statistics */
-        H5F_ENCODE_LENGTH(f, p, hdr->stats.nelmts);       /* Number of elements for the fixed array */
+    /* Magic number */
+    HDmemcpy(image, H5FA_HDR_MAGIC, (size_t)H5_SIZEOF_MAGIC);
+    image += H5_SIZEOF_MAGIC;
 
-        /* Internal information */
-        H5F_addr_encode(f, &p, hdr->dblk_addr);  /* Address of fixed array data block */
+    /* Version # */
+    *image++ = H5FA_HDR_VERSION;
 
-        /* Compute metadata checksum */
-        metadata_chksum = H5_checksum_metadata(buf, (size_t)(p - buf), 0);
+    /* Fixed array type */
+    *image++ = hdr->cparam.cls->id;
 
-        /* Metadata checksum */
-        UINT32ENCODE(p, metadata_chksum);
+    /* General array creation/configuration information */
+    *image++ = hdr->cparam.raw_elmt_size;          /* Element size in file (in bytes) */
+    *image++ = hdr->cparam.max_dblk_page_nelmts_bits;  /* Log2(Max. # of elements in data block page) - i.e. # of bits needed to store max. # of elements in data block page */
 
-	/* Write the array header. */
-        HDassert((size_t)(p - buf) == size);
-	if(H5F_block_write(f, H5FD_MEM_FARRAY_HDR, addr, size, dxpl_id, buf) < 0)
-            H5E_THROW(H5E_WRITEERROR, "unable to save fixed array header to disk")
+    /* Array statistics */
+    H5F_ENCODE_LENGTH(f, image, hdr->stats.nelmts);       /* Number of elements for the fixed array */
 
-	hdr->cache_info.is_dirty = FALSE;
-    } /* end if */
+    /* Internal information */
+    H5F_addr_encode(f, &image, hdr->dblk_addr);  /* Address of fixed array data block */
 
-    if(destroy)
-        if(H5FA__cache_hdr_dest(f, hdr) < 0)
-            H5E_THROW(H5E_CANTFREE, "unable to destroy fixed array header")
+    /* Compute metadata checksum */
+    metadata_chksum = H5_checksum_metadata(_image, (size_t)(image - (uint8_t *)_image), 0);
 
-CATCH
+    /* Metadata checksum */
+    UINT32ENCODE(image, metadata_chksum);
 
-    /* Release resources */
-    if(wb && H5WB_unwrap(wb) < 0)
-	H5E_THROW(H5E_CLOSEERROR, "can't close wrapped buffer")
+    /* Sanity check */
+    HDassert((size_t)(image - (uint8_t *)_image) <= len);
 
-END_FUNC(STATIC)   /* end H5FA__cache_hdr_flush() */
+END_FUNC(STATIC)   /* end H5FA__cache_hdr_serialize() */
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5FA__cache_hdr_clear
+ * Function:	H5FA__cache_hdr_free_icr
  *
- * Purpose:	Mark a fixed array header in memory as non-dirty.
+ * Purpose:	Destroy/release an "in core representation" of a data
+ *              structure
  *
  * Return:	Non-negative on success/Negative on failure
  *
- * Programmer:	Vailin Choi
- *              Thursday, April 30, 2009
+ * Programmer:	Quincey Koziol
+ *              koziol@hdfgroup.org
+ *              August 12, 2013
  *
  *-------------------------------------------------------------------------
  */
 BEGIN_FUNC(STATIC, ERR,
 herr_t, SUCCEED, FAIL,
-H5FA__cache_hdr_clear(H5F_t *f, H5FA_hdr_t *hdr, hbool_t destroy))
-
-    /* Sanity check */
-    HDassert(hdr);
+H5FA__cache_hdr_free_icr(void *thing))
 
-    /* Reset the dirty flag.  */
-    hdr->cache_info.is_dirty = FALSE;
+    /* Check arguments */
+    HDassert(thing);
 
-    if(destroy)
-        if(H5FA__cache_hdr_dest(f, hdr) < 0)
-            H5E_THROW(H5E_CANTFREE, "unable to destroy fixed array header")
+    /* Release the extensible array header */
+    if(H5FA__hdr_dest((H5FA_hdr_t *)thing) < 0)
+        H5E_THROW(H5E_CANTFREE, "can't free fixed array header")
 
 CATCH
 
-END_FUNC(STATIC)   /* end H5FA__cache_hdr_clear() */
+END_FUNC(STATIC)   /* end H5FA__cache_hdr_free_icr() */
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5FA__cache_hdr_size
+ * Function:    H5FA__cache_dblock_get_load_size
  *
- * Purpose:	Compute the size in bytes of a fixed array header
- *		on disk, and return it in *size_ptr.  On failure,
- *		the value of *size_ptr is undefined.
+ * Purpose:     Compute the size of the data structure on disk.
  *
- * Return:	Non-negative on success/Negative on failure
+ * Return:      Non-negative on success/Negative on failure
  *
- * Programmer:	Vailin Choi
- *              Thursday, April 30, 2009
+ * Programmer:  Quincey Koziol
+ *              koziol@hdfgroup.org
+ *              August 12, 2013
  *
  *-------------------------------------------------------------------------
  */
-/* ARGSUSED */
 BEGIN_FUNC(STATIC, NOERR,
 herr_t, SUCCEED, -,
-H5FA__cache_hdr_size(const H5F_t H5_ATTR_UNUSED *f, const H5FA_hdr_t *hdr,
-    size_t *size_ptr))
-
-    /* Sanity check */
-    HDassert(f);
-    HDassert(hdr);
-    HDassert(size_ptr);
-
-    /* Set size value */
-    *size_ptr = hdr->size;
-
-END_FUNC(STATIC)   /* end H5FA__cache_hdr_size() */
+H5FA__cache_dblock_get_load_size(const void *_udata, size_t *image_len))
 
-
-/*-------------------------------------------------------------------------
- * Function:	H5FA__cache_hdr_dest
- *
- * Purpose:	Destroys a fixed array header in memory.
- *
- * Return:	Non-negative on success/Negative on failure
- *
- * Programmer:	Vailin Choi
- *              Thursday, April 30, 2009
- *
- *-------------------------------------------------------------------------
- */
-/* ARGSUSED */
-BEGIN_FUNC(STATIC, ERR,
-herr_t, SUCCEED, FAIL,
-H5FA__cache_hdr_dest(H5F_t *f, H5FA_hdr_t *hdr))
+    /* Local variables */
+    const H5FA_dblock_cache_ud_t *udata = (const H5FA_dblock_cache_ud_t *)_udata;      /* User data */
+    H5FA_dblock_t dblock;           /* Fake data block for computing size */
+    size_t	dblk_page_nelmts;	/* # of elements per data block page */
 
     /* Check arguments */
-    HDassert(f);
-    HDassert(hdr);
-
-    /* Verify that header is clean */
-    HDassert(hdr->cache_info.is_dirty == FALSE);
-
-    /* If we're going to free the space on disk, the address must be valid */
-    HDassert(!hdr->cache_info.free_file_space_on_destroy || H5F_addr_defined(hdr->cache_info.addr));
-
-    /* Check for freeing file space for fixed array header */
-    if(hdr->cache_info.free_file_space_on_destroy) {
-        /* Sanity check address */
-        HDassert(H5F_addr_eq(hdr->addr, hdr->cache_info.addr));
-
-        /* Release the space on disk */
-        /* (XXX: Nasty usage of internal DXPL value! -QAK) */
-        if(H5MF_xfree(f, H5FD_MEM_FARRAY_HDR, H5AC_dxpl_id, hdr->cache_info.addr, (hsize_t)hdr->size) < 0)
-            H5E_THROW(H5E_CANTFREE, "unable to free fixed array header")
+    HDassert(udata);
+    HDassert(udata->hdr);
+    HDassert(image_len);
+
+    /* Set up fake data block for computing size on disk */
+    /* (Note: extracted from H5FA__dblock_alloc) */
+    HDmemset(&dblock, 0, sizeof(dblock));
+
+    /* Set up fake data block for computing size on disk
+     *
+     * need: dblock->hdr
+     *       dblock->npages
+     *       dblock->dblk_page_init_size
+     */
+
+    dblock.hdr = udata->hdr;
+    dblk_page_nelmts = (size_t)1 << udata->hdr->cparam.max_dblk_page_nelmts_bits;
+    if(udata->hdr->cparam.nelmts > dblk_page_nelmts) {
+        dblock.npages = (size_t)(((udata->hdr->cparam.nelmts + dblk_page_nelmts) - 1) / dblk_page_nelmts);
+        dblock.dblk_page_init_size = (dblock.npages + 7) / 8;
     } /* end if */
 
-    /* Release the fixed array header */
-    if(H5FA__hdr_dest(hdr) < 0)
-        H5E_THROW(H5E_CANTFREE, "can't free fixed array header")
-
-CATCH
+    /* Set the image length size */
+    if(!dblock.npages)
+        *image_len = (size_t)H5FA_DBLOCK_SIZE(&dblock);
+    else
+        *image_len = (size_t)H5FA_DBLOCK_PREFIX_SIZE(&dblock);
 
-END_FUNC(STATIC)   /* end H5FA__cache_hdr_dest() */
+END_FUNC(STATIC)   /* end H5FA__cache_dblock_get_load_size() */
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5FA__cache_dblock_load
+ * Function:	H5FA__cache_dblock_deserialize
  *
- * Purpose:	Loads a fixed array data block from the disk.
+ * Purpose:	Loads a data structure from the disk.
  *
- * Return:	Success:	Pointer to a new fixed array data block
+ * Return:	Success:	Pointer to a new B-tree.
  *		Failure:	NULL
  *
- * Programmer:	Vailin Choi
- *              Thursday, April 30, 2009
+ * Programmer:	Quincey Koziol
+ *              koziol@hdfgroup.org
+ *              August 14, 2013
  *
  *-------------------------------------------------------------------------
  */
 BEGIN_FUNC(STATIC, ERR,
-H5FA_dblock_t *, NULL, NULL,
-H5FA__cache_dblock_load(H5F_t *f, hid_t dxpl_id, haddr_t addr, void *_udata))
+void *, NULL, NULL,
+H5FA__cache_dblock_deserialize(const void *_image, size_t len,
+    void *_udata, hbool_t H5_ATTR_UNUSED *dirty))
 
     /* Local variables */
     H5FA_dblock_t  *dblock = NULL;  /* Data block info */
     H5FA_dblock_cache_ud_t *udata = (H5FA_dblock_cache_ud_t *)_udata; /* User data for loading data block */
-    size_t	   size;            /* Data block size */
-    H5WB_t         *wb = NULL;      /* Wrapped buffer for data block data */
-    uint8_t        dblock_buf[H5FA_DBLOCK_BUF_SIZE]; /* Buffer for data block */
-    uint8_t	   *buf;             /* Pointer to data block buffer */
-    const uint8_t  *p;              /* Pointer into raw data buffer */
+    const uint8_t  *image = (const uint8_t *)_image;    /* Pointer into raw data buffer */
     uint32_t       stored_chksum;   /* Stored metadata checksum value */
     uint32_t       computed_chksum; /* Computed metadata checksum value */
     haddr_t        arr_addr;        /* Address of array header in the file */
 
     /* Sanity check */
-    HDassert(f);
-    HDassert(H5F_addr_defined(addr));
-    HDassert(udata && udata->hdr);
+    HDassert(udata);
+    HDassert(udata->hdr);
 
     /* Allocate the fixed array data block */
     if(NULL == (dblock = H5FA__dblock_alloc(udata->hdr)))
 	H5E_THROW(H5E_CANTALLOC, "memory allocation failed for fixed array data block")
 
-    /* Set the fixed array data block's information */
-    dblock->addr = addr;
-
-    /* Wrap the local buffer for serialized info */
-    if(NULL == (wb = H5WB_wrap(dblock_buf, sizeof(dblock_buf))))
-	H5E_THROW(H5E_CANTINIT, "can't wrap buffer")
-
-    /* Compute the size of the fixed array data block on disk */
-    if(!dblock->npages)
-        size = (size_t)H5FA_DBLOCK_SIZE(dblock);
-    else
-        size = H5FA_DBLOCK_PREFIX_SIZE(dblock);
-
-    /* Get a pointer to a buffer that's large enough for serialized info */
-    if(NULL == (buf = (uint8_t *)H5WB_actual(wb, size)))
-	H5E_THROW(H5E_CANTGET, "can't get actual buffer")
+    HDassert(((!dblock->npages) && (len == (size_t)H5FA_DBLOCK_SIZE(dblock))) 
+             || (len == (size_t)H5FA_DBLOCK_PREFIX_SIZE(dblock)));
 
-    /* Read data block from disk */
-    if(H5F_block_read(f, H5FD_MEM_FARRAY_DBLOCK, addr, size, dxpl_id, buf) < 0)
-	H5E_THROW(H5E_READERROR, "can't read fixed array data block")
-
-    /* Get temporary pointer to serialized header */
-    p = buf;
+    /* Set the fixed array data block's information */
+    dblock->addr = udata->dblk_addr;
 
     /* Magic number */
-    if(HDmemcmp(p, H5FA_DBLOCK_MAGIC, (size_t)H5_SIZEOF_MAGIC))
+    if(HDmemcmp(image, H5FA_DBLOCK_MAGIC, (size_t)H5_SIZEOF_MAGIC))
 	H5E_THROW(H5E_BADVALUE, "wrong fixed array data block signature")
-    p += H5_SIZEOF_MAGIC;
+    image += H5_SIZEOF_MAGIC;
 
     /* Version */
-    if(*p++ != H5FA_DBLOCK_VERSION)
+    if(*image++ != H5FA_DBLOCK_VERSION)
 	H5E_THROW(H5E_VERSION, "wrong fixed array data block version")
 
     /* Fixed array type */
-    if(*p++ != (uint8_t)udata->hdr->cparam.cls->id)
+    if(*image++ != (uint8_t)udata->hdr->cparam.cls->id)
 	H5E_THROW(H5E_BADTYPE, "incorrect fixed array class")
 
     /* Address of header for array that owns this block (just for file integrity checks) */
-    H5F_addr_decode(f, &p, &arr_addr);
+    H5F_addr_decode(udata->hdr->f, &image, &arr_addr);
     if(H5F_addr_ne(arr_addr, udata->hdr->addr))
 	H5E_THROW(H5E_BADVALUE, "wrong fixed array header address")
 
     /* Page initialization flags */
     if(dblock->npages > 0) {
-	HDmemcpy(dblock->dblk_page_init, p, dblock->dblk_page_init_size);
-        p += dblock->dblk_page_init_size;
+	HDmemcpy(dblock->dblk_page_init, image, dblock->dblk_page_init_size);
+        image += dblock->dblk_page_init_size;
     } /* end if */
 
     /* Only decode elements if the data block is not paged */
     if(!dblock->npages) {
         /* Decode elements in data block */
         /* Convert from raw elements on disk into native elements in memory */
-        if((udata->hdr->cparam.cls->decode)(p, dblock->elmts, (size_t)udata->hdr->stats.nelmts, udata->hdr->cb_ctx) < 0)
+        if((udata->hdr->cparam.cls->decode)(image, dblock->elmts, (size_t)udata->hdr->cparam.nelmts, udata->hdr->cb_ctx) < 0)
             H5E_THROW(H5E_CANTDECODE, "can't decode fixed array data elements")
-        p += (udata->hdr->stats.nelmts * udata->hdr->cparam.raw_elmt_size);
+        image += (udata->hdr->cparam.nelmts * udata->hdr->cparam.raw_elmt_size);
     } /* end if */
 
     /* Sanity check */
     /* (allow for checksum not decoded yet) */
-    HDassert((size_t)(p - buf) == (size - H5FA_SIZEOF_CHKSUM));
+    HDassert((size_t)(image - (const uint8_t *)_image) == (len - H5FA_SIZEOF_CHKSUM));
 
     /* Set the data block's size */
     dblock->size = H5FA_DBLOCK_SIZE(dblock);
 
     /* Compute checksum on data block */
-    computed_chksum = H5_checksum_metadata(buf, (size_t)(p - buf), 0);
+    computed_chksum = H5_checksum_metadata(_image, (size_t)(image - (const uint8_t *)_image), 0);
 
     /* Metadata checksum */
-    UINT32DECODE(p, stored_chksum);
+    UINT32DECODE(image, stored_chksum);
 
     /* Sanity check */
-    HDassert((size_t)(p - buf) == size);
+    HDassert((size_t)(image - (const uint8_t *)_image) == len);
 
     /* Verify checksum */
     if(stored_chksum != computed_chksum)
@@ -608,317 +596,292 @@ H5FA__cache_dblock_load(H5F_t *f, hid_t dxpl_id, haddr_t addr, void *_udata))
 CATCH
 
     /* Release resources */
-    if(wb && H5WB_unwrap(wb) < 0)
-	H5E_THROW(H5E_CLOSEERROR, "can't close wrapped buffer")
     if(!ret_value)
         if(dblock && H5FA__dblock_dest(dblock) < 0)
             H5E_THROW(H5E_CANTFREE, "unable to destroy fixed array data block")
 
-END_FUNC(STATIC)   /* end H5FA__cache_dblock_load() */
+END_FUNC(STATIC)   /* end H5FA__cache_dblock_deserialize() */
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5FA__cache_dblock_flush
+ * Function:    H5FA__cache_dblock_image_len
  *
- * Purpose:	Flushes a dirty fixed array data block to disk.
+ * Purpose:     Compute the size of the data structure on disk.
  *
- * Return:	Non-negative on success/Negative on failure
+ * Return:      Non-negative on success/Negative on failure
  *
- * Programmer:	Vailin Choi
- *              Thursday, April 30, 2009
+ * Programmer:  Quincey Koziol
+ *              koziol@hdfgroup.org
+ *              August 14, 2013
  *
  *-------------------------------------------------------------------------
  */
-BEGIN_FUNC(STATIC, ERR,
-herr_t, SUCCEED, FAIL,
-H5FA__cache_dblock_flush(H5F_t *f, hid_t dxpl_id, hbool_t destroy, haddr_t addr,
-    H5FA_dblock_t *dblock, unsigned H5_ATTR_UNUSED * flags_ptr))
+BEGIN_FUNC(STATIC, NOERR,
+herr_t, SUCCEED, -,
+H5FA__cache_dblock_image_len(const void *_thing, size_t *image_len,
+    hbool_t H5_ATTR_UNUSED *compressed_ptr, size_t H5_ATTR_UNUSED *compressed_image_len_ptr))
 
     /* Local variables */
-    H5WB_t *wb = NULL;                     /* Wrapped buffer for serializing data */
-    uint8_t ser_buf[H5FA_DBLOCK_BUF_SIZE]; /* Serialization buffer */
+    const H5FA_dblock_t *dblock = (const H5FA_dblock_t *)_thing;      /* Pointer to the object */
 
-    /* Sanity check */
-    HDassert(f);
-    HDassert(H5F_addr_defined(addr));
+    /* Check arguments */
     HDassert(dblock);
-    HDassert(dblock->hdr);
-
-    if(dblock->cache_info.is_dirty) {
-        uint8_t	*buf;           /* Temporary raw data buffer */
-        uint8_t *p;             /* Pointer into raw data buffer */
-        size_t	size;           /* Index block size on disk */
-        uint32_t metadata_chksum; /* Computed metadata checksum value */
+    HDassert(image_len);
 
-        /* Wrap the local buffer for serialized info */
-        if(NULL == (wb = H5WB_wrap(ser_buf, sizeof(ser_buf))))
-            H5E_THROW(H5E_CANTINIT, "can't wrap buffer")
-
-        /* Compute the size of the data block on disk */
-        if(!dblock->npages)
-            size = (size_t)dblock->size;
-        else
-            size = H5FA_DBLOCK_PREFIX_SIZE(dblock);
+    /* Set the image length size */
+    if(!dblock->npages)
+        *image_len = (size_t)dblock->size;
+    else
+        *image_len = H5FA_DBLOCK_PREFIX_SIZE(dblock);
 
-        /* Get a pointer to a buffer that's large enough for serialized info */
-        if(NULL == (buf = (uint8_t *)H5WB_actual(wb, size)))
-            H5E_THROW(H5E_CANTGET, "can't get actual buffer")
+END_FUNC(STATIC)   /* end H5FA__cache_dblock_image_len() */
 
-        /* Get temporary pointer to serialized info */
-        p = buf;
+
+/*-------------------------------------------------------------------------
+ * Function:	H5FA__cache_dblock_serialize
+ *
+ * Purpose:	Flushes a dirty object to disk.
+ *
+ * Return:	Non-negative on success/Negative on failure
+ *
+ * Programmer:	Quincey Koziol
+ *              koziol@hdfgroup.org
+ *              August 14, 2013
+ *
+ *-------------------------------------------------------------------------
+ */
+BEGIN_FUNC(STATIC, ERR,
+herr_t, SUCCEED, FAIL,
+H5FA__cache_dblock_serialize(const H5F_t *f, void *_image, size_t H5_ATTR_UNUSED len,
+    void *_thing))
 
-        /* Magic number */
-        HDmemcpy(p, H5FA_DBLOCK_MAGIC, (size_t)H5_SIZEOF_MAGIC);
-        p += H5_SIZEOF_MAGIC;
+    /* Local variables */
+    H5FA_dblock_t *dblock = (H5FA_dblock_t *)_thing;      /* Pointer to the object to serialize */
+    uint8_t *image = (uint8_t *)_image;         /* Pointer into raw data buffer */
+    uint32_t metadata_chksum; /* Computed metadata checksum value */
 
-        /* Version # */
-        *p++ = H5FA_DBLOCK_VERSION;
+    /* Check arguments */
+    HDassert(f);
+    HDassert(image);
+    HDassert(dblock);
+    HDassert(dblock->hdr);
 
-        /* Fixed array type */
-        *p++ = dblock->hdr->cparam.cls->id;
+    /* Magic number */
+    HDmemcpy(image, H5FA_DBLOCK_MAGIC, (size_t)H5_SIZEOF_MAGIC);
+    image += H5_SIZEOF_MAGIC;
 
-        /* Address of array header for array which owns this block */
-        H5F_addr_encode(f, &p, dblock->hdr->addr);
+    /* Version # */
+    *image++ = H5FA_DBLOCK_VERSION;
 
-        /* Page init flags */
-	if(dblock->npages > 0) {
-	    /* Store the 'page init' bitmasks */
-            HDmemcpy(p, dblock->dblk_page_init, dblock->dblk_page_init_size);
-            p += dblock->dblk_page_init_size;
-	} /* end if */
+    /* Fixed array type */
+    *image++ = dblock->hdr->cparam.cls->id;
 
-        /* Only encode elements if the data block is not paged */
-        if(!dblock->npages) {
-            /* Encode elements in data block */
+    /* Address of array header for array which owns this block */
+    H5F_addr_encode(f, &image, dblock->hdr->addr);
 
-            /* Convert from native elements in memory into raw elements on disk */
-            H5_CHECK_OVERFLOW(dblock->hdr->cparam.nelmts, /* From: */hsize_t, /* To: */size_t);
-            if((dblock->hdr->cparam.cls->encode)(p, dblock->elmts, (size_t)dblock->hdr->cparam.nelmts, dblock->hdr->cb_ctx) < 0)
-                H5E_THROW(H5E_CANTENCODE, "can't encode fixed array data elements")
-            p += (dblock->hdr->cparam.nelmts * dblock->hdr->cparam.raw_elmt_size);
-        } /* end if */
+    /* Page init flags */
+    if(dblock->npages > 0) {
+        /* Store the 'page init' bitmasks */
+        HDmemcpy(image, dblock->dblk_page_init, dblock->dblk_page_init_size);
+        image += dblock->dblk_page_init_size;
+    } /* end if */
 
-        /* Compute metadata checksum */
-        metadata_chksum = H5_checksum_metadata(buf, (size_t)(p - buf), 0);
+    /* Only encode elements if the data block is not paged */
+    if(!dblock->npages) {
+        /* Encode elements in data block */
 
-        /* Metadata checksum */
-        UINT32ENCODE(p, metadata_chksum);
+        /* Convert from native elements in memory into raw elements on disk */
+        H5_CHECK_OVERFLOW(dblock->hdr->cparam.nelmts, /* From: */hsize_t, /* To: */size_t);
+        if((dblock->hdr->cparam.cls->encode)(image, dblock->elmts, (size_t)dblock->hdr->cparam.nelmts, dblock->hdr->cb_ctx) < 0)
+            H5E_THROW(H5E_CANTENCODE, "can't encode fixed array data elements")
+        image += (dblock->hdr->cparam.nelmts * dblock->hdr->cparam.raw_elmt_size);
+    } /* end if */
 
-	/* Write the data block */
-        HDassert((size_t)(p - buf) == size);
-	if(H5F_block_write(f, H5FD_MEM_FARRAY_DBLOCK, addr, size, dxpl_id, buf) < 0)
-            H5E_THROW(H5E_WRITEERROR, "unable to save fixed array data block to disk")
+    /* Compute metadata checksum */
+    metadata_chksum = H5_checksum_metadata(_image, (size_t)(image - (uint8_t *)_image), 0);
 
-	dblock->cache_info.is_dirty = FALSE;
-    } /* end if */
+    /* Metadata checksum */
+    UINT32ENCODE(image, metadata_chksum);
 
-    if(destroy)
-        if(H5FA__cache_dblock_dest(f, dblock) < 0)
-            H5E_THROW(H5E_CANTFREE, "unable to destroy fixed array data block")
+    /* Sanity check */
+    HDassert((size_t)(image - (uint8_t *)_image) <= len);
 
 CATCH
 
-    /* Release resources */
-    if(wb && H5WB_unwrap(wb) < 0)
-	H5E_THROW(H5E_CLOSEERROR, "can't close wrapped buffer")
-
-END_FUNC(STATIC)   /* end H5FA__cache_dblock_flush() */
+END_FUNC(STATIC)   /* end H5FA__cache_dblock_serialize() */
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5FA__cache_dblock_clear
+ * Function:	H5FA__cache_dblock_free_icr
  *
- * Purpose:	Mark a fixed array data block in memory as non-dirty.
+ * Purpose:	Destroy/release an "in core representation" of a data
+ *              structure
  *
  * Return:	Non-negative on success/Negative on failure
  *
- * Programmer:	Vailin Choi
- *              Thursday, April 30, 2009
+ * Programmer:	Quincey Koziol
+ *              koziol@hdfgroup.org
+ *              August 14, 2013
  *
  *-------------------------------------------------------------------------
  */
 BEGIN_FUNC(STATIC, ERR,
 herr_t, SUCCEED, FAIL,
-H5FA__cache_dblock_clear(H5F_t *f, H5FA_dblock_t *dblock, hbool_t destroy))
+H5FA__cache_dblock_free_icr(void *_thing))
 
-    /* Sanity check */
-    HDassert(dblock);
+    H5FA_dblock_t *dblock = (H5FA_dblock_t *)_thing;    /* Pointer to the object */
 
-    /* Reset the dirty flag */
-    dblock->cache_info.is_dirty = FALSE;
+    /* Check arguments */
+    HDassert(dblock);
 
-    if(destroy)
-        if(H5FA__cache_dblock_dest(f, dblock) < 0)
-            H5E_THROW(H5E_CANTFREE, "unable to destroy fixed array data block")
+    /* Release the fixed array data block */
+    if(H5FA__dblock_dest(dblock) < 0)
+        H5E_THROW(H5E_CANTFREE, "can't free fixed array data block")
 
 CATCH
 
-END_FUNC(STATIC)   /* end H5FA__cache_dblock_clear() */
+END_FUNC(STATIC)   /* end H5FA__cache_dblock_free_icr() */
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5FA__cache_dblock_size
- *
- * Purpose:	Compute the size in bytes of a fixed array data block
- *		on disk, and return it in *size_ptr.  On failure,
- *		the value of *size_ptr is undefined.
- *
+ * Function:	H5FA__cache_dblock_fsf_size
+ *
+ * Purpose:	Tell the metadata cache the actual amount of file space
+ *		to free when a dblock entry is destroyed with the free
+ *		file space block set.
+ *
+ *		This function is needed when the data block is paged, as 
+ *		the datablock header and all its pages are allocted as a
+ *		single contiguous chunk of file space, and must be 
+ *		deallocated the same way.
+ *
+ *		The size of the chunk of memory in which the dblock
+ *		header and all its pages is stored in the size field,
+ *		so we simply pass that value back to the cache.
+ *
+ *		If the datablock is not paged, then the size field of 
+ *		the cache_info contains the correct size.  However this
+ *		value will be the same as the size field, so we return
+ *		the contents of the size field to the cache in this case
+ *		as well.
+ *		
  * Return:	Non-negative on success/Negative on failure
  *
- * Programmer:	Vailin Choi
- *              Thursday, April 30, 2009
+ * Programmer:	John Mainzer
+ *              12/5/14
  *
  *-------------------------------------------------------------------------
  */
-/* ARGSUSED */
 BEGIN_FUNC(STATIC, NOERR,
 herr_t, SUCCEED, -,
-H5FA__cache_dblock_size(const H5F_t H5_ATTR_UNUSED *f, const H5FA_dblock_t *dblock,
-    size_t *size_ptr))
+H5FA__cache_dblock_fsf_size(const void *_thing, size_t *fsf_size))
 
-    /* Sanity check */
-    HDassert(f);
+    const H5FA_dblock_t *dblock = (const H5FA_dblock_t *)_thing;    /* Pointer to the object */
+
+    /* Check arguments */
     HDassert(dblock);
-    HDassert(size_ptr);
+    HDassert(dblock->cache_info.magic == H5C__H5C_CACHE_ENTRY_T_MAGIC);
+    HDassert(dblock->cache_info.type == H5AC_FARRAY_DBLOCK);
+    HDassert(fsf_size);
 
-    /* Set size value */
-    if(!dblock->npages)
-        *size_ptr = (size_t)dblock->size;
-    else
-        *size_ptr = H5FA_DBLOCK_PREFIX_SIZE(dblock);
+    *fsf_size = dblock->size;
 
-END_FUNC(STATIC)   /* end H5FA__cache_dblock_size() */
+END_FUNC(STATIC)   /* end H5FA__cache_dblock_fsf_size() */
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5FA__cache_dblock_dest
+ * Function:    H5FA__cache_dblk_page_get_load_size
  *
- * Purpose:	Destroys a fixed array data block in memory.
+ * Purpose:     Compute the size of the data structure on disk.
  *
- * Return:	Non-negative on success/Negative on failure
+ * Return:      Non-negative on success/Negative on failure
  *
- * Programmer:	Vailin Choi
- *              Thursday, April 30, 2009
+ * Programmer:  Quincey Koziol
+ *              koziol@hdfgroup.org
+ *              August 14, 2013
  *
  *-------------------------------------------------------------------------
  */
-/* ARGSUSED */
-BEGIN_FUNC(STATIC, ERR,
-herr_t, SUCCEED, FAIL,
-H5FA__cache_dblock_dest(H5F_t *f, H5FA_dblock_t *dblock))
-
-    /* Sanity check */
-    HDassert(f);
-    HDassert(dblock);
-
-    /* Verify that data block is clean */
-    HDassert(dblock->cache_info.is_dirty == FALSE);
-
-    /* If we're going to free the space on disk, the address must be valid */
-    HDassert(!dblock->cache_info.free_file_space_on_destroy || H5F_addr_defined(dblock->cache_info.addr));
-
-    /* Check for freeing file space for fixed array data block */
-    if(dblock->cache_info.free_file_space_on_destroy) {
-        /* Sanity check address */
-        HDassert(H5F_addr_eq(dblock->addr, dblock->cache_info.addr));
+BEGIN_FUNC(STATIC, NOERR,
+herr_t, SUCCEED, -,
+H5FA__cache_dblk_page_get_load_size(const void *_udata, size_t *image_len))
 
-        /* Release the space on disk */
-        /* (Includes space for pages!) */
-        /* (XXX: Nasty usage of internal DXPL value! -QAK) */
-        if(H5MF_xfree(f, H5FD_MEM_FARRAY_DBLOCK, H5AC_dxpl_id, dblock->cache_info.addr, (hsize_t)dblock->size) < 0)
-            H5E_THROW(H5E_CANTFREE, "unable to free fixed array data block")
-    } /* end if */
+    /* Local variables */
+    const H5FA_dblk_page_cache_ud_t *udata = (const H5FA_dblk_page_cache_ud_t *)_udata;      /* User data */
 
-    /* Release the data block */
-    if(H5FA__dblock_dest(dblock) < 0)
-        H5E_THROW(H5E_CANTFREE, "can't free fixed array data block")
+    /* Check arguments */
+    HDassert(udata);
+    HDassert(udata->hdr);
+    HDassert(udata->nelmts > 0);
+    HDassert(image_len);
 
-CATCH
+    *image_len = (size_t)H5FA_DBLK_PAGE_SIZE(udata->hdr, udata->nelmts);
 
-END_FUNC(STATIC)   /* end H5FA__cache_dblock_dest() */
+END_FUNC(STATIC)   /* end H5FA__cache_dblk_page_get_load_size() */
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5FA__cache_dblk_page_load
+ * Function:	H5FA__cache_dblk_page_deserialize
  *
- * Purpose:	Loads a fixed array data block page from the disk.
+ * Purpose:	Loads a data structure from the disk.
  *
- * Return:	Success:	Pointer to a new fixed array data block page
+ * Return:	Success:	Pointer to a new B-tree.
  *		Failure:	NULL
  *
- * Programmer:	Vailin Choi
- *              Thursday, April 30, 2009
+ * Programmer:	Quincey Koziol
+ *              koziol@hdfgroup.org
+ *              August 14, 2013
  *
  *-------------------------------------------------------------------------
  */
 BEGIN_FUNC(STATIC, ERR,
-H5FA_dblk_page_t *, NULL, NULL,
-H5FA__cache_dblk_page_load(H5F_t *f, hid_t dxpl_id, haddr_t addr, void *_udata))
+void *, NULL, NULL,
+H5FA__cache_dblk_page_deserialize(const void *_image, size_t len,
+    void *_udata, hbool_t H5_ATTR_UNUSED *dirty))
 
     /* Local variables */
     H5FA_dblk_page_t	*dblk_page = NULL; /* Data block page info */
     H5FA_dblk_page_cache_ud_t *udata = (H5FA_dblk_page_cache_ud_t *)_udata; /* User data for loading data block page */
-    size_t		size;           /* Data block page size */
-    H5WB_t              *wb = NULL;     /* Wrapped buffer for data block page data */
-    uint8_t             dblk_page_buf[H5FA_DBLK_PAGE_BUF_SIZE]; /* Buffer for data block page */
-    uint8_t		*buf;           /* Pointer to data block page buffer */
-    const uint8_t	*p;             /* Pointer into raw data buffer */
+    const uint8_t	*image = (const uint8_t *)_image;       /* Pointer into raw data buffer */
     uint32_t            stored_chksum;  /* Stored metadata checksum value */
     uint32_t            computed_chksum; /* Computed metadata checksum value */
 
     /* Sanity check */
-    HDassert(f);
-    HDassert(H5F_addr_defined(addr));
-    HDassert(udata && udata->hdr && udata->nelmts > 0);
+    HDassert(udata);
+    HDassert(udata->hdr);
+    HDassert(udata->nelmts > 0);
+    HDassert(H5F_addr_defined(udata->dblk_page_addr));
 
     /* Allocate the fixed array data block page */
     if(NULL == (dblk_page = H5FA__dblk_page_alloc(udata->hdr, udata->nelmts)))
 	H5E_THROW(H5E_CANTALLOC, "memory allocation failed for fixed array data block page")
 
     /* Set the fixed array data block's information */
-    dblk_page->addr = addr;
-
-    /* Wrap the local buffer for serialized info */
-    if(NULL == (wb = H5WB_wrap(dblk_page_buf, sizeof(dblk_page_buf))))
-	H5E_THROW(H5E_CANTINIT, "can't wrap buffer")
-
-    /* Compute the size of the fixed array data block page on disk */
-    size = H5FA_DBLK_PAGE_SIZE(udata->hdr, udata->nelmts);
-
-    /* Get a pointer to a buffer that's large enough for serialized info */
-    if(NULL == (buf = (uint8_t *)H5WB_actual(wb, size)))
-	H5E_THROW(H5E_CANTGET, "can't get actual buffer")
-
-    /* Read data block page from disk */
-    if(H5F_block_read(f, H5FD_MEM_FARRAY_DBLK_PAGE, addr, size, dxpl_id, buf) < 0)
-	H5E_THROW(H5E_READERROR, "can't read fixed array data block page")
-
-    /* Get temporary pointer to serialized header */
-    p = buf;
+    dblk_page->addr = udata->dblk_page_addr;
 
     /* Internal information */
 
     /* Decode elements in data block page */
     /* Convert from raw elements on disk into native elements in memory */
-    if((udata->hdr->cparam.cls->decode)(p, dblk_page->elmts, udata->nelmts, udata->hdr->cb_ctx) < 0)
+    if((udata->hdr->cparam.cls->decode)(image, dblk_page->elmts, udata->nelmts, udata->hdr->cb_ctx) < 0)
         H5E_THROW(H5E_CANTDECODE, "can't decode fixed array data elements")
-    p += (udata->nelmts * udata->hdr->cparam.raw_elmt_size);
+    image += (udata->nelmts * udata->hdr->cparam.raw_elmt_size);
 
     /* Sanity check */
     /* (allow for checksum not decoded yet) */
-    HDassert((size_t)(p - buf) == (size - H5FA_SIZEOF_CHKSUM));
+    HDassert((size_t)(image - (const uint8_t *)_image) == (len - H5FA_SIZEOF_CHKSUM));
 
     /* Set the data block page's size */
-    dblk_page->size = size;
+    dblk_page->size = len;
 
     /* Compute checksum on data block */
-    computed_chksum = H5_checksum_metadata(buf, (size_t)(p - buf), 0);
+    computed_chksum = H5_checksum_metadata(_image, (size_t)(image - (const uint8_t *)_image), 0);
 
     /* Metadata checksum */
-    UINT32DECODE(p, stored_chksum);
+    UINT32DECODE(image, stored_chksum);
 
     /* Sanity check */
-    HDassert((size_t)(p - buf) == dblk_page->size);
+    HDassert((size_t)(image - (const uint8_t *)_image) == dblk_page->size);
 
     /* Verify checksum */
     if(stored_chksum != computed_chksum)
@@ -930,192 +893,122 @@ H5FA__cache_dblk_page_load(H5F_t *f, hid_t dxpl_id, haddr_t addr, void *_udata))
 CATCH
 
     /* Release resources */
-    if(wb && H5WB_unwrap(wb) < 0)
-	H5E_THROW(H5E_CLOSEERROR, "can't close wrapped buffer")
     if(!ret_value)
         if(dblk_page && H5FA__dblk_page_dest(dblk_page) < 0)
             H5E_THROW(H5E_CANTFREE, "unable to destroy fixed array data block page")
 
-END_FUNC(STATIC)   /* end H5FA__cache_dblk_page_load() */
+END_FUNC(STATIC)   /* end H5FA__cache_dblk_page_deserialize() */
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5FA__cache_dblk_page_flush
+ * Function:    H5FA__cache_dblk_page_image_len
  *
- * Purpose:	Flushes a dirty fixed array data block page to disk.
+ * Purpose:     Compute the size of the data structure on disk.
  *
- * Return:	Non-negative on success/Negative on failure
+ * Return:      Non-negative on success/Negative on failure
  *
- * Programmer:	Vailin Choi
- *              Thursday, April 30, 2009
+ * Programmer:  Quincey Koziol
+ *              koziol@hdfgroup.org
+ *              August 14, 2013
  *
  *-------------------------------------------------------------------------
  */
-BEGIN_FUNC(STATIC, ERR,
-herr_t, SUCCEED, FAIL,
-H5FA__cache_dblk_page_flush(H5F_t *f, hid_t dxpl_id, hbool_t destroy, haddr_t addr,
-    H5FA_dblk_page_t *dblk_page, unsigned H5_ATTR_UNUSED * flags_ptr))
+BEGIN_FUNC(STATIC, NOERR,
+herr_t, SUCCEED, -,
+H5FA__cache_dblk_page_image_len(const void *_thing, size_t *image_len,
+    hbool_t H5_ATTR_UNUSED *compressed_ptr, size_t H5_ATTR_UNUSED *compressed_image_len_ptr))
 
     /* Local variables */
-    H5WB_t *wb = NULL;                  /* Wrapped buffer for serializing data */
-    uint8_t ser_buf[H5FA_DBLK_PAGE_BUF_SIZE]; /* Serialization buffer */
+    const H5FA_dblk_page_t *dblk_page = (const H5FA_dblk_page_t *)_thing;      /* Pointer to the object */
 
-    /* Sanity check */
-    HDassert(f);
-    HDassert(H5F_addr_defined(addr));
+    /* Check arguments */
     HDassert(dblk_page);
-    HDassert(dblk_page->hdr);
-
-    if(dblk_page->cache_info.is_dirty) {
-        uint8_t	*buf;           /* Temporary raw data buffer */
-        uint8_t *p;             /* Pointer into raw data buffer */
-        size_t	size;           /* Index block size on disk */
-        uint32_t metadata_chksum; /* Computed metadata checksum value */
-
-        /* Wrap the local buffer for serialized info */
-        if(NULL == (wb = H5WB_wrap(ser_buf, sizeof(ser_buf))))
-            H5E_THROW(H5E_CANTINIT, "can't wrap buffer")
-
-        /* Compute the size of the data block on disk */
-        size = dblk_page->size;
-
-        /* Get a pointer to a buffer that's large enough for serialized info */
-        if(NULL == (buf = (uint8_t *)H5WB_actual(wb, size)))
-            H5E_THROW(H5E_CANTGET, "can't get actual buffer")
-
-        /* Get temporary pointer to serialized info */
-        p = buf;
-
-        /* Internal information */
-
-        /* Encode elements in data block page */
-
-        /* Convert from native elements in memory into raw elements on disk */
-        if((dblk_page->hdr->cparam.cls->encode)(p, dblk_page->elmts, dblk_page->nelmts, dblk_page->hdr->cb_ctx) < 0)
-            H5E_THROW(H5E_CANTENCODE, "can't encode fixed array data elements")
-        p += (dblk_page->nelmts * dblk_page->hdr->cparam.raw_elmt_size);
-
-        /* Compute metadata checksum */
-        metadata_chksum = H5_checksum_metadata(buf, (size_t)(p - buf), 0);
-
-        /* Metadata checksum */
-        UINT32ENCODE(p, metadata_chksum);
-
-	/* Write the data block */
-        HDassert((size_t)(p - buf) == size);
-	if(H5F_block_write(f, H5FD_MEM_FARRAY_DBLK_PAGE, addr, size, dxpl_id, buf) < 0)
-            H5E_THROW(H5E_WRITEERROR, "unable to save fixed array data block page to disk")
-
-	dblk_page->cache_info.is_dirty = FALSE;
-    } /* end if */
-
-    if(destroy)
-        if(H5FA__cache_dblk_page_dest(f, dblk_page) < 0)
-            H5E_THROW(H5E_CANTFREE, "unable to destroy fixed array data block page")
+    HDassert(image_len);
 
-CATCH
-
-    /* Release resources */
-    if(wb && H5WB_unwrap(wb) < 0)
-	H5E_THROW(H5E_CLOSEERROR, "can't close wrapped buffer")
+    /* Set the image length size */
+    *image_len = dblk_page->size; 
 
-END_FUNC(STATIC)   /* end H5FA__cache_dblk_page_flush() */
+END_FUNC(STATIC)   /* end H5FA__cache_dblk_page_image_len() */
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5FA__cache_dblk_page_clear
+ * Function:	H5FA__cache_dblk_page_serialize
  *
- * Purpose:	Mark a fixed array data block page in memory as non-dirty.
+ * Purpose:	Flushes a dirty object to disk.
  *
  * Return:	Non-negative on success/Negative on failure
  *
- * Programmer:	Vailin Choi
- *              Thursday, April 30, 2009
+ * Programmer:	Quincey Koziol
+ *              koziol@hdfgroup.org
+ *              August 14, 2013
  *
  *-------------------------------------------------------------------------
  */
 BEGIN_FUNC(STATIC, ERR,
 herr_t, SUCCEED, FAIL,
-H5FA__cache_dblk_page_clear(H5F_t *f, H5FA_dblk_page_t *dblk_page, hbool_t destroy))
+H5FA__cache_dblk_page_serialize(const H5F_t *f, void *_image, size_t H5_ATTR_UNUSED len,
+    void *_thing))
+
+    /* Local variables */
+    H5FA_dblk_page_t *dblk_page = (H5FA_dblk_page_t *)_thing;      /* Pointer to the object to serialize */
+    uint8_t *image = (uint8_t *)_image;         /* Pointer into raw data buffer */
+    uint32_t metadata_chksum;   /* Computed metadata checksum value */
 
     /* Sanity check */
+    HDassert(f);
+    HDassert(image);
     HDassert(dblk_page);
+    HDassert(dblk_page->hdr);
 
-    /* Reset the dirty flag */
-    dblk_page->cache_info.is_dirty = FALSE;
+    /* Internal information */
 
-    if(destroy)
-        if(H5FA__cache_dblk_page_dest(f, dblk_page) < 0)
-            H5E_THROW(H5E_CANTFREE, "unable to destroy fixed array data block page")
+    /* Encode elements in data block page */
 
-CATCH
+    /* Convert from native elements in memory into raw elements on disk */
+    if((dblk_page->hdr->cparam.cls->encode)(image, dblk_page->elmts, dblk_page->nelmts, dblk_page->hdr->cb_ctx) < 0)
+        H5E_THROW(H5E_CANTENCODE, "can't encode fixed array data elements")
+    image += (dblk_page->nelmts * dblk_page->hdr->cparam.raw_elmt_size);
 
-END_FUNC(STATIC)   /* end H5FA__cache_dblk_page_clear() */
+    /* Compute metadata checksum */
+    metadata_chksum = H5_checksum_metadata(_image, (size_t)(image - (uint8_t *)_image), 0);
 
-
-/*-------------------------------------------------------------------------
- * Function:	H5FA__cache_dblk_page_size
- *
- * Purpose:	Compute the size in bytes of a fixed array data block page
- *		on disk, and return it in *size_ptr.  On failure,
- *		the value of *size_ptr is undefined.
- *
- * Return:	Non-negative on success/Negative on failure
- *
- * Programmer:	Vailin Choi
- *              Thursday, April 30, 2009
- *
- *-------------------------------------------------------------------------
- */
-/* ARGSUSED */
-BEGIN_FUNC(STATIC, NOERR,
-herr_t, SUCCEED, -,
-H5FA__cache_dblk_page_size(const H5F_t H5_ATTR_UNUSED *f, const H5FA_dblk_page_t *dblk_page,
-    size_t *size_ptr))
+    /* Metadata checksum */
+    UINT32ENCODE(image, metadata_chksum);
 
     /* Sanity check */
-    HDassert(f);
-    HDassert(dblk_page);
-    HDassert(size_ptr);
+    HDassert((size_t)(image - (uint8_t *)_image) <= len);
 
-    /* Set size value */
-    *size_ptr = dblk_page->size;
+CATCH
 
-END_FUNC(STATIC)   /* end H5FA__cache_dblk_page_size() */
+END_FUNC(STATIC)   /* end H5FA__cache_dblk_page_serialize() */
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5FA__cache_dblk_page_dest
- *
- * Purpose:	Destroys a fixed array data block page in memory.
+ * Function:	H5FA__cache_dblk_page_free_icr
  *
- * Note:	Does _not_ free the space for the page on disk, that is
- *              handled through the data block that "owns" the page.
+ * Purpose:	Destroy/release an "in core representation" of a data
+ *              structure
  *
  * Return:	Non-negative on success/Negative on failure
  *
- * Programmer:	Vailin Choi
- *              Thursday, April 30, 2009
+ * Programmer:	Quincey Koziol
+ *              koziol@hdfgroup.org
+ *              August 14, 2013
  *
  *-------------------------------------------------------------------------
  */
-/* ARGSUSED */
 BEGIN_FUNC(STATIC, ERR,
 herr_t, SUCCEED, FAIL,
-H5FA__cache_dblk_page_dest(H5F_t H5_ATTR_UNUSED *f, H5FA_dblk_page_t *dblk_page))
+H5FA__cache_dblk_page_free_icr(void *thing))
 
-    /* Sanity check */
-    HDassert(f);
-    HDassert(dblk_page);
-
-    /* Verify that data block page is clean */
-    HDassert(dblk_page->cache_info.is_dirty == FALSE);
+    /* Check arguments */
+    HDassert(thing);
 
-    /* Release the data block page */
-    if(H5FA__dblk_page_dest(dblk_page) < 0)
+    /* Release the fixed array data block page */
+    if(H5FA__dblk_page_dest((H5FA_dblk_page_t *)thing) < 0)
         H5E_THROW(H5E_CANTFREE, "can't free fixed array data block page")
 
 CATCH
 
-END_FUNC(STATIC)   /* end H5FA__cache_dblk_page_dest() */
+END_FUNC(STATIC)   /* end H5FA__cache_dblk_page_free_icr() */
 
diff --git a/src/H5FAdbg.c b/src/H5FAdbg.c
index d5239d3..6a84fc9 100644
--- a/src/H5FAdbg.c
+++ b/src/H5FAdbg.c
@@ -117,7 +117,7 @@ H5FA__hdr_debug(H5F_t *f, hid_t dxpl_id, haddr_t addr, FILE *stream, int indent,
     } /* end if */
 
     /* Load the fixed array header */
-    if(NULL == (hdr = H5FA__hdr_protect(f, dxpl_id, addr, dbg_ctx, H5AC_READ)))
+    if(NULL == (hdr = H5FA__hdr_protect(f, dxpl_id, addr, dbg_ctx, H5AC__READ_ONLY_FLAG)))
 	H5E_THROW(H5E_CANTPROTECT, "unable to load fixed array header")
 
     /* Print opening message */
@@ -198,11 +198,11 @@ H5FA__dblock_debug(H5F_t *f, hid_t dxpl_id, haddr_t addr, FILE *stream, int inde
     } /* end if */
 
     /* Load the fixed array header */
-    if(NULL == (hdr = H5FA__hdr_protect(f, dxpl_id, hdr_addr, dbg_ctx, H5AC_READ)))
+    if(NULL == (hdr = H5FA__hdr_protect(f, dxpl_id, hdr_addr, dbg_ctx, H5AC__READ_ONLY_FLAG)))
 	H5E_THROW(H5E_CANTPROTECT, "unable to load fixed array header")
 
     /* Protect data block */
-    if(NULL == (dblock = H5FA__dblock_protect(hdr, dxpl_id, addr, H5AC_READ)))
+    if(NULL == (dblock = H5FA__dblock_protect(hdr, dxpl_id, addr, H5AC__READ_ONLY_FLAG)))
         H5E_THROW(H5E_CANTPROTECT, "unable to protect fixed array data block, address = %llu", (unsigned long long)addr)
 
     /* Print opening message */
@@ -246,7 +246,7 @@ H5FA__dblock_debug(H5F_t *f, hid_t dxpl_id, haddr_t addr, FILE *stream, int inde
 		if(((page_idx + 1) == dblock->npages) && (nelmts_left = hdr->cparam.nelmts % dblock->dblk_page_nelmts))
 		    dblk_page_nelmts = (size_t)nelmts_left;
 
-		if(NULL == (dblk_page = H5FA__dblk_page_protect(hdr, dxpl_id, dblk_page_addr, dblk_page_nelmts, H5AC_READ)))
+		if(NULL == (dblk_page = H5FA__dblk_page_protect(hdr, dxpl_id, dblk_page_addr, dblk_page_nelmts, H5AC__READ_ONLY_FLAG)))
 		    H5E_THROW(H5E_CANTPROTECT, "unable to protect fixed array data block page, address = %llu", (unsigned long long)dblk_page_addr)
 
 		HDfprintf(stream, "%*sElements in page %Zu:\n", indent, "", page_idx);
diff --git a/src/H5FAdblkpage.c b/src/H5FAdblkpage.c
index 1f6b706..e1ea3ac 100644
--- a/src/H5FAdblkpage.c
+++ b/src/H5FAdblkpage.c
@@ -207,7 +207,7 @@ END_FUNC(PKG)   /* end H5FA__dblk_page_create() */
 BEGIN_FUNC(PKG, ERR,
 H5FA_dblk_page_t *, NULL, NULL,
 H5FA__dblk_page_protect(H5FA_hdr_t *hdr, hid_t dxpl_id, haddr_t dblk_page_addr,
-    size_t dblk_page_nelmts, H5AC_protect_t rw))
+    size_t dblk_page_nelmts, unsigned flags))
 
     /* Local variables */
     H5FA_dblk_page_cache_ud_t udata;      /* Information needed for loading data block page */
@@ -220,12 +220,16 @@ HDfprintf(stderr, "%s: Called\n", FUNC);
     HDassert(hdr);
     HDassert(H5F_addr_defined(dblk_page_addr));
 
+    /* only the H5AC__READ_ONLY_FLAG is permitted */
+    HDassert((flags & (unsigned)(~H5AC__READ_ONLY_FLAG)) == 0);
+
     /* Set up user data */
     udata.hdr = hdr;
     udata.nelmts = dblk_page_nelmts;
+    udata.dblk_page_addr = dblk_page_addr;
 
     /* Protect the data block page */
-    if(NULL == (ret_value = (H5FA_dblk_page_t *)H5AC_protect(hdr->f, dxpl_id, H5AC_FARRAY_DBLK_PAGE, dblk_page_addr, &udata, rw)))
+    if(NULL == (ret_value = (H5FA_dblk_page_t *)H5AC_protect(hdr->f, dxpl_id, H5AC_FARRAY_DBLK_PAGE, dblk_page_addr, &udata, flags)))
         H5E_THROW(H5E_CANTPROTECT, "unable to protect fixed array data block page, address = %llu", (unsigned long long)dblk_page_addr)
 
 CATCH
diff --git a/src/H5FAdblock.c b/src/H5FAdblock.c
index e6e0e74..42dafeb 100644
--- a/src/H5FAdblock.c
+++ b/src/H5FAdblock.c
@@ -263,7 +263,7 @@ END_FUNC(PKG)   /* end H5FA__dblock_create() */
 BEGIN_FUNC(PKG, ERR,
 H5FA_dblock_t *, NULL, NULL,
 H5FA__dblock_protect(H5FA_hdr_t *hdr, hid_t dxpl_id, haddr_t dblk_addr,
-    H5AC_protect_t rw))
+    unsigned flags))
 
     /* Local variables */
     H5FA_dblock_cache_ud_t udata;      /* Information needed for loading data block */
@@ -276,11 +276,15 @@ HDfprintf(stderr, "%s: Called\n", FUNC);
     HDassert(hdr);
     HDassert(H5F_addr_defined(dblk_addr));
 
+    /* only the H5AC__READ_ONLY_FLAG flag is permitted */
+    HDassert((flags & (unsigned)(~H5AC__READ_ONLY_FLAG)) == 0);
+
     /* Set up user data */
     udata.hdr = hdr;
+    udata.dblk_addr = dblk_addr;
 
     /* Protect the data block */
-    if(NULL == (ret_value = (H5FA_dblock_t *)H5AC_protect(hdr->f, dxpl_id, H5AC_FARRAY_DBLOCK, dblk_addr, &udata, rw)))
+    if(NULL == (ret_value = (H5FA_dblock_t *)H5AC_protect(hdr->f, dxpl_id, H5AC_FARRAY_DBLOCK, dblk_addr, &udata, flags)))
         H5E_THROW(H5E_CANTPROTECT, "unable to protect fixed array data block, address = %llu", (unsigned long long)dblk_addr)
 
 CATCH
@@ -350,7 +354,7 @@ HDfprintf(stderr, "%s: Called\n", FUNC);
     HDassert(H5F_addr_defined(dblk_addr));
 
     /* Protect data block */
-    if(NULL == (dblock = H5FA__dblock_protect(hdr, dxpl_id, dblk_addr, H5AC_WRITE)))
+    if(NULL == (dblock = H5FA__dblock_protect(hdr, dxpl_id, dblk_addr, H5AC__NO_FLAGS_SET)))
         H5E_THROW(H5E_CANTPROTECT, "unable to protect fixed array data block, address = %llu", (unsigned long long)dblk_addr)
 
     /* Check if data block is paged */
diff --git a/src/H5FAhdr.c b/src/H5FAhdr.c
index 23c20bc..9083a52 100644
--- a/src/H5FAhdr.c
+++ b/src/H5FAhdr.c
@@ -408,16 +408,25 @@ END_FUNC(PKG)   /* end H5FA__hdr_modified() */
 BEGIN_FUNC(PKG, ERR,
 H5FA_hdr_t *, NULL, NULL,
 H5FA__hdr_protect(H5F_t *f, hid_t dxpl_id, haddr_t fa_addr, void *ctx_udata,
-    H5AC_protect_t rw))
+    unsigned flags))
 
     /* Local variables */
+    H5FA_hdr_cache_ud_t udata;  /* User data for cache callbacks */
 
     /* Sanity check */
     HDassert(f);
     HDassert(H5F_addr_defined(fa_addr));
 
+    /* only the H5AC__READ_ONLY_FLAG is permitted */
+    HDassert((flags & (unsigned)(~H5AC__READ_ONLY_FLAG)) == 0);
+
+    /* Set up user data for cache callbacks */
+    udata.f = f;
+    udata.addr = fa_addr;
+    udata.ctx_udata = ctx_udata;
+
     /* Protect the header */
-    if(NULL == (ret_value = (H5FA_hdr_t *)H5AC_protect(f, dxpl_id, H5AC_FARRAY_HDR, fa_addr, ctx_udata, rw)))
+    if(NULL == (ret_value = (H5FA_hdr_t *)H5AC_protect(f, dxpl_id, H5AC_FARRAY_HDR, fa_addr, &udata, flags)))
         H5E_THROW(H5E_CANTPROTECT, "unable to protect fixed array header, address = %llu", (unsigned long long)fa_addr)
 
 CATCH
diff --git a/src/H5FApkg.h b/src/H5FApkg.h
index e7993a6..bed9c83 100644
--- a/src/H5FApkg.h
+++ b/src/H5FApkg.h
@@ -206,15 +206,24 @@ struct H5FA_t {
 
 /* Metadata cache callback user data types */
 
+/* Info needed for loading header */
+typedef struct H5FA_hdr_cache_ud_t {
+    H5F_t      *f;              /* Pointer to file for fixed array */
+    haddr_t    addr;            /* Address of header on disk */
+    void       *ctx_udata;      /* User context for class */
+} H5FA_hdr_cache_ud_t;
+
 /* Info needed for loading data block */
 typedef struct H5FA_dblock_cache_ud_t {
     H5FA_hdr_t *hdr;            /* Shared fixed array information */
+    haddr_t     dblk_addr;      /* Address of data block on disk */
 } H5FA_dblock_cache_ud_t;
 
 /* Info needed for loading data block page */
 typedef struct H5FA_dblk_page_cache_ud_t {
     H5FA_hdr_t *hdr;            /* Shared fixed array information */
     size_t      nelmts;         /* Number of elements in data block page */
+    haddr_t     dblk_page_addr; /* Address of data block page on disk */
 } H5FA_dblk_page_cache_ud_t;
 
 
@@ -254,7 +263,7 @@ H5_DLL herr_t H5FA__hdr_fuse_incr(H5FA_hdr_t *hdr);
 H5_DLL size_t H5FA__hdr_fuse_decr(H5FA_hdr_t *hdr);
 H5_DLL herr_t H5FA__hdr_modified(H5FA_hdr_t *hdr);
 H5_DLL H5FA_hdr_t *H5FA__hdr_protect(H5F_t *f, hid_t dxpl_id, haddr_t fa_addr,
-    void *ctx_udata, H5AC_protect_t rw);
+    void *ctx_udata, unsigned flags);
 H5_DLL herr_t H5FA__hdr_unprotect(H5FA_hdr_t *hdr, hid_t dxpl_id, unsigned cache_flags);
 H5_DLL herr_t H5FA__hdr_delete(H5FA_hdr_t *hdr, hid_t dxpl_id);
 H5_DLL herr_t H5FA__hdr_dest(H5FA_hdr_t *hdr);
@@ -264,7 +273,7 @@ H5_DLL H5FA_dblock_t *H5FA__dblock_alloc(H5FA_hdr_t *hdr);
 H5_DLL haddr_t H5FA__dblock_create(H5FA_hdr_t *hdr, hid_t dxpl_id, hbool_t *hdr_dirty);
 H5_DLL unsigned H5FA__dblock_sblk_idx(const H5FA_hdr_t *hdr, hsize_t idx);
 H5_DLL H5FA_dblock_t *H5FA__dblock_protect(H5FA_hdr_t *hdr, hid_t dxpl_id,
-    haddr_t dblk_addr, H5AC_protect_t rw);
+    haddr_t dblk_addr, unsigned flags);
 H5_DLL herr_t H5FA__dblock_unprotect(H5FA_dblock_t *dblock, hid_t dxpl_id,
     unsigned cache_flags);
 H5_DLL herr_t H5FA__dblock_delete(H5FA_hdr_t *hdr, hid_t dxpl_id,
@@ -276,7 +285,7 @@ H5_DLL herr_t H5FA__dblk_page_create(H5FA_hdr_t *hdr, hid_t dxpl_id,
     haddr_t addr, size_t nelmts);
 H5_DLL H5FA_dblk_page_t *H5FA__dblk_page_alloc(H5FA_hdr_t *hdr, size_t nelmts);
 H5_DLL H5FA_dblk_page_t *H5FA__dblk_page_protect(H5FA_hdr_t *hdr, hid_t dxpl_id,
-    haddr_t dblk_page_addr, size_t dblk_page_nelmts, H5AC_protect_t rw);
+    haddr_t dblk_page_addr, size_t dblk_page_nelmts, unsigned flags);
 H5_DLL herr_t H5FA__dblk_page_unprotect(H5FA_dblk_page_t *dblk_page,
     hid_t dxpl_id, unsigned cache_flags);
 H5_DLL herr_t H5FA__dblk_page_dest(H5FA_dblk_page_t *dblk_page);
diff --git a/src/H5FDfamily.c b/src/H5FDfamily.c
index d993ad0..9edbc72 100644
--- a/src/H5FDfamily.c
+++ b/src/H5FDfamily.c
@@ -905,7 +905,7 @@ H5FD_family_query(const H5FD_t * _file, unsigned long *flags /* out */)
 
         /* Check for flags that are set by h5repart */
         if(file && file->repart_members)
-            *flags |= H5FD_FEAT_DIRTY_SBLK_LOAD; /* Mark the superblock dirty when it is loaded (so the family member sizes are rewritten) */
+            *flags |= H5FD_FEAT_DIRTY_DRVRINFO_LOAD; /* Mark the superblock dirty when it is loaded (so the family member sizes are rewritten) */
     } /* end if */
 
     FUNC_LEAVE_NOAPI(SUCCEED)
diff --git a/src/H5FDpublic.h b/src/H5FDpublic.h
index df5d5cf..58066cc 100644
--- a/src/H5FDpublic.h
+++ b/src/H5FDpublic.h
@@ -198,12 +198,12 @@ typedef enum H5F_mem_t	H5FD_mem_t;
      */
 #define H5FD_FEAT_IGNORE_DRVRINFO       0x00000020
     /*
-     * Defining the H5FD_FEAT_DIRTY_SBLK_LOAD for a VFL driver means that
-     * the library will mark the superblock dirty when the file is opened
+     * Defining the H5FD_FEAT_DIRTY_DRVRINFO_LOAD for a VFL driver means that
+     * the library will mark the driver info dirty when the file is opened
      * R/W.  This will cause the driver info to be re-encoded when the file
      * is flushed/closed.
      */
-#define H5FD_FEAT_DIRTY_SBLK_LOAD       0x00000040
+#define H5FD_FEAT_DIRTY_DRVRINFO_LOAD   0x00000040
     /*
      * Defining the H5FD_FEAT_POSIX_COMPAT_HANDLE for a VFL driver means that
      * the handle for the VFD (returned with the 'get_handle' callback) is
diff --git a/src/H5FS.c b/src/H5FS.c
index 42ea070..182ac05 100644
--- a/src/H5FS.c
+++ b/src/H5FS.c
@@ -216,7 +216,7 @@ HDfprintf(stderr, "%s: Opening free space manager, fs_addr = %a, nclasses = %Zu\
     cache_udata.addr = fs_addr;
 
     /* Protect the free space header */
-    if(NULL == (fspace = (H5FS_t *)H5AC_protect(f, dxpl_id, H5AC_FSPACE_HDR, fs_addr, &cache_udata, H5AC_READ)))
+    if(NULL == (fspace = (H5FS_t *)H5AC_protect(f, dxpl_id, H5AC_FSPACE_HDR, fs_addr, &cache_udata, H5AC__READ_ONLY_FLAG)))
         HGOTO_ERROR(H5E_FSPACE, H5E_CANTPROTECT, NULL, "unable to load free space header")
 #ifdef H5FS_DEBUG
 HDfprintf(stderr, "%s: fspace->sect_addr = %a\n", FUNC, fspace->sect_addr);
@@ -329,7 +329,7 @@ HDfprintf(stderr, "%s: Deleting free space manager, fs_addr = %a\n", FUNC, fs_ad
 #endif /* H5FS_DEBUG */
 
     /* Protect the free space header */
-    if(NULL == (fspace = (H5FS_t *)H5AC_protect(f, dxpl_id, H5AC_FSPACE_HDR, fs_addr, &cache_udata, H5AC_WRITE)))
+    if(NULL == (fspace = (H5FS_t *)H5AC_protect(f, dxpl_id, H5AC_FSPACE_HDR, fs_addr, &cache_udata, H5AC__NO_FLAGS_SET)))
         HGOTO_ERROR(H5E_FSPACE, H5E_CANTPROTECT, FAIL, "unable to protect free space header")
 
     /* Sanity check */
@@ -361,8 +361,19 @@ HDfprintf(stderr, "%s: Expunging free space section info from cache\n", FUNC);
 #endif /* H5FS_DEBUG */
             /* Evict the free space section info from the metadata cache */
             /* (Free file space) */
-            if(H5AC_expunge_entry(f, dxpl_id, H5AC_FSPACE_SINFO, fspace->sect_addr, H5AC__FREE_FILE_SPACE_FLAG) < 0)
-                HGOTO_ERROR(H5E_HEAP, H5E_CANTREMOVE, FAIL, "unable to remove free space section info from cache")
+            {
+                unsigned cache_flags = H5AC__NO_FLAGS_SET;
+
+                /* if the indirect block is in real file space, tell
+                 * the cache to free its file space.
+                 */
+                if (!H5F_IS_TMP_ADDR(f, fspace->sect_addr))
+                    cache_flags |= H5AC__FREE_FILE_SPACE_FLAG;
+
+                if(H5AC_expunge_entry(f, dxpl_id, H5AC_FSPACE_SINFO, fspace->sect_addr, cache_flags) < 0)
+                    HGOTO_ERROR(H5E_HEAP, H5E_CANTREMOVE, FAIL, "unable to remove free space section info from cache")
+            }
+
 #ifdef H5FS_DEBUG
 HDfprintf(stderr, "%s: Done expunging free space section info from cache\n", FUNC);
 #endif /* H5FS_DEBUG */
@@ -938,7 +949,7 @@ H5FS_free(H5F_t *f, H5FS_t *fspace, hid_t dxpl_id)
             cache_udata.f = f;
             cache_udata.dxpl_id = dxpl_id;
             cache_udata.fspace = fspace;
-	    if(NULL == (fspace->sinfo = (H5FS_sinfo_t *)H5AC_protect(f, dxpl_id, H5AC_FSPACE_SINFO, fspace->sect_addr, &cache_udata, H5AC_READ)))
+	    if(NULL == (fspace->sinfo = (H5FS_sinfo_t *)H5AC_protect(f, dxpl_id, H5AC_FSPACE_SINFO, fspace->sect_addr, &cache_udata, H5AC__READ_ONLY_FLAG)))
 		HGOTO_ERROR(H5E_FSPACE, H5E_CANTPROTECT, FAIL, "unable to protect free space section info")
 
 	    /* Unload and release ownership of the free-space manager section info */
@@ -979,7 +990,7 @@ H5FS_free(H5F_t *f, H5FS_t *fspace, hid_t dxpl_id)
             cache_udata.nclasses = 0;
             cache_udata.classes = NULL;
             cache_udata.cls_init_udata = NULL;
-	    if(NULL == (fspace = (H5FS_t *)H5AC_protect(f, dxpl_id, H5AC_FSPACE_HDR, fspace->addr, &cache_udata, H5AC_READ)))
+	    if(NULL == (fspace = (H5FS_t *)H5AC_protect(f, dxpl_id, H5AC_FSPACE_HDR, fspace->addr, &cache_udata, H5AC__READ_ONLY_FLAG)))
 		HGOTO_ERROR(H5E_FSPACE, H5E_CANTPROTECT, FAIL, "unable to protect free space section info")
 
 	    /* Unpin the free-space manager header */
diff --git a/src/H5FScache.c b/src/H5FScache.c
index 461af99..25a9c5e 100644
--- a/src/H5FScache.c
+++ b/src/H5FScache.c
@@ -49,9 +49,6 @@
 #define H5FS_HDR_VERSION        0               /* Header */
 #define H5FS_SINFO_VERSION      0               /* Serialized sections */
 
-/* Size of stack buffer for serialized headers */
-#define H5FS_HDR_BUF_SIZE               256
-
 
 /******************/
 /* Local Typedefs */
@@ -60,7 +57,7 @@
 /* User data for skip list iterator callback for iterating over section size nodes when syncing */
 typedef struct {
     H5FS_sinfo_t *sinfo;        /* Free space section info */
-    uint8_t **p;                /* Pointer to address of buffer pointer to serialize with */
+    uint8_t **image;            /* Pointer to address of buffer pointer to serialize with */
     unsigned sect_cnt_size;     /* # of bytes to encode section size counts in */
 } H5FS_iter_ud_t;
 
@@ -75,20 +72,35 @@ typedef struct {
 /********************/
 
 /* Section info routines */
-static herr_t H5FS_sinfo_serialize_sect_cb(void *_item, void H5_ATTR_UNUSED *key, void *_udata);
-static herr_t H5FS_sinfo_serialize_node_cb(void *_item, void H5_ATTR_UNUSED *key, void *_udata);
+static herr_t H5FS__sinfo_serialize_sect_cb(void *_item, void H5_ATTR_UNUSED *key, void *_udata);
+static herr_t H5FS__sinfo_serialize_node_cb(void *_item, void H5_ATTR_UNUSED *key, void *_udata);
 
 /* Metadata cache callbacks */
-static H5FS_t *H5FS_cache_hdr_load(H5F_t *f, hid_t dxpl_id, haddr_t addr, void *udata);
-static herr_t H5FS_cache_hdr_flush(H5F_t *f, hid_t dxpl_id, hbool_t destroy, haddr_t addr, H5FS_t *fspace, unsigned H5_ATTR_UNUSED * flags_ptr);
-static herr_t H5FS_cache_hdr_dest(H5F_t *f, H5FS_t *fspace);
-static herr_t H5FS_cache_hdr_clear(H5F_t *f, H5FS_t *fspace, hbool_t destroy);
-static herr_t H5FS_cache_hdr_size(const H5F_t *f, const H5FS_t *fspace, size_t *size_ptr);
-static H5FS_sinfo_t *H5FS_cache_sinfo_load(H5F_t *f, hid_t dxpl_id, haddr_t addr, void *udata);
-static herr_t H5FS_cache_sinfo_flush(H5F_t *f, hid_t dxpl_id, hbool_t destroy, haddr_t addr, H5FS_sinfo_t *sinfo, unsigned H5_ATTR_UNUSED * flags_ptr);
-static herr_t H5FS_cache_sinfo_dest(H5F_t *f, H5FS_sinfo_t *sinfo);
-static herr_t H5FS_cache_sinfo_clear(H5F_t *f, H5FS_sinfo_t *sinfo, hbool_t destroy);
-static herr_t H5FS_cache_sinfo_size(const H5F_t *f, const H5FS_sinfo_t *sinfo, size_t *size_ptr);
+static herr_t H5FS__cache_hdr_get_load_size(const void *udata, size_t *image_len);
+static void *H5FS__cache_hdr_deserialize(const void *image, size_t len,
+    void *udata, hbool_t *dirty);
+static herr_t H5FS__cache_hdr_image_len(const void *thing, size_t *image_len,
+    hbool_t *compressed_ptr, size_t *compressed_image_len_ptr);
+static herr_t H5FS__cache_hdr_pre_serialize(const H5F_t *f, hid_t dxpl_id,
+    void *thing, haddr_t addr, size_t len, size_t compressed_len, 
+    haddr_t *new_addr, size_t *new_len, size_t *new_compressed_len, 
+    unsigned *flags);
+static herr_t H5FS__cache_hdr_serialize(const H5F_t *f, void *image, 
+    size_t len, void *thing);
+static herr_t H5FS__cache_hdr_free_icr(void *thing);
+
+static herr_t H5FS__cache_sinfo_get_load_size(const void *udata, size_t *image_len);
+static void *H5FS__cache_sinfo_deserialize(const void *image, size_t len,
+    void *udata, hbool_t *dirty);
+static herr_t H5FS__cache_sinfo_image_len(const void *thing, size_t *image_len,
+    hbool_t *compressed_ptr, size_t *compressed_image_len_ptr);
+static herr_t H5FS__cache_sinfo_pre_serialize(const H5F_t *f, hid_t dxpl_id,
+    void *thing, haddr_t addr, size_t len, size_t compressed_len, 
+    haddr_t *new_addr, size_t *new_len, size_t *new_compressed_len, 
+    unsigned *flags);
+static herr_t H5FS__cache_sinfo_serialize(const H5F_t *f, void *image,
+    size_t len, void *thing);
+static herr_t H5FS__cache_sinfo_free_icr(void *thing);
 
 
 /*********************/
@@ -97,24 +109,36 @@ static herr_t H5FS_cache_sinfo_size(const H5F_t *f, const H5FS_sinfo_t *sinfo, s
 
 /* H5FS header inherits cache-like properties from H5AC */
 const H5AC_class_t H5AC_FSPACE_HDR[1] = {{
-    H5AC_FSPACE_HDR_ID,
-    (H5AC_load_func_t)H5FS_cache_hdr_load,
-    (H5AC_flush_func_t)H5FS_cache_hdr_flush,
-    (H5AC_dest_func_t)H5FS_cache_hdr_dest,
-    (H5AC_clear_func_t)H5FS_cache_hdr_clear,
-    (H5AC_notify_func_t)NULL,
-    (H5AC_size_func_t)H5FS_cache_hdr_size,
+    H5AC_FSPACE_HDR_ID,                 /* Metadata client ID */
+    "Free Space Header",                /* Metadata client name (for debugging) */
+    H5FD_MEM_FSPACE_HDR,                /* File space memory type for client */
+    H5AC__CLASS_NO_FLAGS_SET,           /* Client class behavior flags */
+    H5FS__cache_hdr_get_load_size,      /* 'get_load_size' callback */
+    H5FS__cache_hdr_deserialize,        /* 'deserialize' callback */
+    H5FS__cache_hdr_image_len,          /* 'image_len' callback */
+    H5FS__cache_hdr_pre_serialize,      /* 'pre_serialize' callback */
+    H5FS__cache_hdr_serialize,          /* 'serialize' callback */
+    NULL,                               /* 'notify' callback */
+    H5FS__cache_hdr_free_icr,           /* 'free_icr' callback */
+    NULL,			        /* 'clear' callback */
+    NULL,                               /* 'fsf_size' callback */
 }};
 
-/* H5FS serialized sections inherit cache-like properties from H5AC */
+/* H5FS section info inherits cache-like properties from H5AC */
 const H5AC_class_t H5AC_FSPACE_SINFO[1] = {{
-    H5AC_FSPACE_SINFO_ID,
-    (H5AC_load_func_t)H5FS_cache_sinfo_load,
-    (H5AC_flush_func_t)H5FS_cache_sinfo_flush,
-    (H5AC_dest_func_t)H5FS_cache_sinfo_dest,
-    (H5AC_clear_func_t)H5FS_cache_sinfo_clear,
-    (H5AC_notify_func_t)NULL,
-    (H5AC_size_func_t)H5FS_cache_sinfo_size,
+    H5AC_FSPACE_SINFO_ID,               /* Metadata client ID */
+    "Free Space Section Info",          /* Metadata client name (for debugging) */
+    H5FD_MEM_FSPACE_SINFO,              /* File space memory type for client */
+    H5AC__CLASS_NO_FLAGS_SET,           /* Client class behavior flags */
+    H5FS__cache_sinfo_get_load_size,    /* 'get_load_size' callback */
+    H5FS__cache_sinfo_deserialize,      /* 'deserialize' callback */
+    H5FS__cache_sinfo_image_len,        /* 'image_len' callback */
+    H5FS__cache_sinfo_pre_serialize,    /* 'pre_serialize' callback */
+    H5FS__cache_sinfo_serialize,        /* 'serialize' callback */
+    NULL,                               /* 'notify' callback */
+    H5FS__cache_sinfo_free_icr,         /* 'free_icr' callback */
+    NULL,			        /* 'clear' callback */
+    NULL,                               /* 'fsf_size' callback */
 }};
 
 
@@ -127,44 +151,73 @@ const H5AC_class_t H5AC_FSPACE_SINFO[1] = {{
 /* Local Variables */
 /*******************/
 
-/* Declare a free list to manage free space section data to/from disk */
-H5FL_BLK_DEFINE_STATIC(sect_block);
-
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5FS_cache_hdr_load
+ * Function:    H5FS__cache_hdr_get_load_size
  *
- * Purpose:	Loads a free space manager header from the disk.
+ * Purpose:     Compute the size of the data structure on disk.
  *
- * Return:      Success:        Pointer to a new free space header
- *              Failure:        NULL
+ * Return:      Non-negative on success/Negative on failure
  *
  * Programmer:  Quincey Koziol
- *              koziol@ncsa.uiuc.edu
- *              May  2 2006
+ *              koziol@hdfgroup.org
+ *              August 14, 2013
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+H5FS__cache_hdr_get_load_size(const void *_udata, size_t *image_len)
+{
+    const H5FS_hdr_cache_ud_t *udata = (const H5FS_hdr_cache_ud_t *)_udata; /* User-data for metadata cache callback */
+
+    FUNC_ENTER_STATIC_NOERR
+
+    /* Check arguments */
+    HDassert(image_len);
+
+    /* Set the image length size */
+    *image_len = (size_t)H5FS_HEADER_SIZE(udata->f);
+
+    FUNC_LEAVE_NOAPI(SUCCEED)
+} /* end H5FS__cache_hdr_get_load_size() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:	H5FS__cache_hdr_deserialize
+ *
+ * Purpose:	Given a buffer containing the on disk image of the free space
+ *      	manager section info, allocate an instance of H5FS_t, load
+ *      	it with the data contained in the image, and return a pointer
+ *              to the new instance.
+ *
+ * Return:	Success:	Pointer to new object
+ *		Failure:	NULL
+ *
+ * Programmer:	Quincey Koziol
+ *		koziol@hdfgroup.org
+ *		August 18 2013
  *
  *-------------------------------------------------------------------------
  */
-static H5FS_t *
-H5FS_cache_hdr_load(H5F_t *f, hid_t dxpl_id, haddr_t addr, void *_udata)
+static void *
+H5FS__cache_hdr_deserialize(const void *_image, size_t len, void *_udata, 
+    hbool_t H5_ATTR_UNUSED *dirty)
 {
     H5FS_t		*fspace = NULL; /* Free space header info */
-    H5FS_hdr_cache_ud_t *udata = (H5FS_hdr_cache_ud_t *)_udata; /* user data for callback */
-    H5WB_t              *wb = NULL;     /* Wrapped buffer for header data */
-    uint8_t             hdr_buf[H5FS_HDR_BUF_SIZE]; /* Buffer for header */
-    uint8_t		*hdr;           /* Pointer to header buffer */
-    const uint8_t	*p;             /* Pointer into raw data buffer */
+    H5FS_hdr_cache_ud_t *udata = (H5FS_hdr_cache_ud_t *)_udata;  /* User data for callback */
+    const uint8_t	*image = (const uint8_t *)_image;       /* Pointer into raw data buffer */
     uint32_t            stored_chksum;  /* Stored metadata checksum value */
     uint32_t            computed_chksum; /* Computed metadata checksum value */
     unsigned            nclasses;       /* Number of section classes */
     H5FS_t		*ret_value;     /* Return value */
 
-    FUNC_ENTER_NOAPI_NOINIT
+    FUNC_ENTER_STATIC
 
     /* Check arguments */
-    HDassert(f);
+    HDassert(image);
     HDassert(udata);
+    HDassert(udata->f);
 
     /* Allocate a new free space manager */
     if(NULL == (fspace = H5FS__new(udata->f, udata->nclasses, udata->classes, udata->cls_init_udata)))
@@ -173,80 +226,69 @@ H5FS_cache_hdr_load(H5F_t *f, hid_t dxpl_id, haddr_t addr, void *_udata)
     /* Set free space manager's internal information */
     fspace->addr = udata->addr;
 
-    /* Wrap the local buffer for serialized header info */
-    if(NULL == (wb = H5WB_wrap(hdr_buf, sizeof(hdr_buf))))
-        HGOTO_ERROR(H5E_FSPACE, H5E_CANTINIT, NULL, "can't wrap buffer")
-
-    /* Get a pointer to a buffer that's large enough for header */
-    if(NULL == (hdr = (uint8_t *)H5WB_actual(wb, fspace->hdr_size)))
-        HGOTO_ERROR(H5E_FSPACE, H5E_NOSPACE, NULL, "can't get actual buffer")
-
-    /* Read header from disk */
-    if(H5F_block_read(f, H5FD_MEM_FSPACE_HDR, addr, fspace->hdr_size, dxpl_id, hdr) < 0)
-	HGOTO_ERROR(H5E_FSPACE, H5E_READERROR, NULL, "can't read free space header")
-
-    p = hdr;
-
     /* Magic number */
-    if(HDmemcmp(p, H5FS_HDR_MAGIC, (size_t)H5_SIZEOF_MAGIC))
+    if(HDmemcmp(image, H5FS_HDR_MAGIC, (size_t)H5_SIZEOF_MAGIC))
 	HGOTO_ERROR(H5E_FSPACE, H5E_CANTLOAD, NULL, "wrong free space header signature")
-    p += H5_SIZEOF_MAGIC;
+    image += H5_SIZEOF_MAGIC;
 
     /* Version */
-    if(*p++ != H5FS_HDR_VERSION)
+    if(*image++ != H5FS_HDR_VERSION)
 	HGOTO_ERROR(H5E_FSPACE, H5E_CANTLOAD, NULL, "wrong free space header version")
 
     /* Client ID */
-    fspace->client = (H5FS_client_t)*p++;
+    fspace->client = (H5FS_client_t)*image++;
     if(fspace->client >= H5FS_NUM_CLIENT_ID)
 	HGOTO_ERROR(H5E_FSPACE, H5E_CANTLOAD, NULL, "unknown client ID in free space header")
 
     /* Total space tracked */
-    H5F_DECODE_LENGTH(udata->f, p, fspace->tot_space);
+    H5F_DECODE_LENGTH(udata->f, image, fspace->tot_space);
 
     /* Total # of free space sections tracked */
-    H5F_DECODE_LENGTH(udata->f, p, fspace->tot_sect_count);
+    H5F_DECODE_LENGTH(udata->f, image, fspace->tot_sect_count);
 
     /* # of serializable free space sections tracked */
-    H5F_DECODE_LENGTH(udata->f, p, fspace->serial_sect_count);
+    H5F_DECODE_LENGTH(udata->f, image, fspace->serial_sect_count);
 
     /* # of ghost free space sections tracked */
-    H5F_DECODE_LENGTH(udata->f, p, fspace->ghost_sect_count);
+    H5F_DECODE_LENGTH(udata->f, image, fspace->ghost_sect_count);
 
     /* # of section classes */
     /* (only check if we actually have some classes) */
-    UINT16DECODE(p, nclasses);
+    UINT16DECODE(image, nclasses);
     if(fspace->nclasses > 0 && fspace->nclasses != nclasses)
 	HGOTO_ERROR(H5E_FSPACE, H5E_CANTLOAD, NULL, "section class count mismatch")
 
     /* Shrink percent */
-    UINT16DECODE(p, fspace->shrink_percent);
+    UINT16DECODE(image, fspace->shrink_percent);
 
     /* Expand percent */
-    UINT16DECODE(p, fspace->expand_percent);
+    UINT16DECODE(image, fspace->expand_percent);
 
-    /* Size of address space free space sections are within (log2 of actual value) */
-    UINT16DECODE(p, fspace->max_sect_addr);
+    /* Size of address space free space sections are within 
+     * (log2 of actual value) 
+     */
+    UINT16DECODE(image, fspace->max_sect_addr);
 
     /* Max. size of section to track */
-    H5F_DECODE_LENGTH(udata->f, p, fspace->max_sect_size);
+    H5F_DECODE_LENGTH(udata->f, image, fspace->max_sect_size);
 
     /* Address of serialized free space sections */
-    H5F_addr_decode(udata->f, &p, &fspace->sect_addr);
+    H5F_addr_decode(udata->f, &image, &fspace->sect_addr);
 
     /* Size of serialized free space sections */
-    H5F_DECODE_LENGTH(udata->f, p, fspace->sect_size);
+    H5F_DECODE_LENGTH(udata->f, image, fspace->sect_size);
 
     /* Allocated size of serialized free space sections */
-    H5F_DECODE_LENGTH(udata->f, p, fspace->alloc_sect_size);
+    H5F_DECODE_LENGTH(udata->f, image, fspace->alloc_sect_size);
 
     /* Compute checksum on indirect block */
-    computed_chksum = H5_checksum_metadata(hdr, (size_t)(p - (const uint8_t *)hdr), 0);
+    computed_chksum = H5_checksum_metadata(_image, (size_t)(image - (const uint8_t *)_image), 0);
 
     /* Metadata checksum */
-    UINT32DECODE(p, stored_chksum);
+    UINT32DECODE(image, stored_chksum);
 
-    HDassert((size_t)(p - (const uint8_t *)hdr) == fspace->hdr_size);
+    /* Sanity check */
+    HDassert((size_t)(image - (const uint8_t *)_image) <= len);
 
     /* Verify checksum */
     if(stored_chksum != computed_chksum)
@@ -257,177 +299,432 @@ H5FS_cache_hdr_load(H5F_t *f, hid_t dxpl_id, haddr_t addr, void *_udata)
 
 done:
     /* Release resources */
-    if(wb && H5WB_unwrap(wb) < 0)
-        HDONE_ERROR(H5E_FSPACE, H5E_CLOSEERROR, NULL, "can't close wrapped buffer")
     if(!ret_value && fspace)
         if(H5FS__hdr_dest(fspace) < 0)
             HDONE_ERROR(H5E_FSPACE, H5E_CANTFREE, NULL, "unable to destroy free space header")
 
     FUNC_LEAVE_NOAPI(ret_value)
-} /* end H5FS_cache_hdr_load() */ /*lint !e818 Can't make udata a pointer to const */
+} /* end H5FS__cache_hdr_deserialize() */
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5FS_cache_hdr_flush
+ * Function:    H5FS__cache_hdr_image_len
  *
- * Purpose:	Flushes a dirty free space header to disk.
+ * Purpose:     Compute the size of the data structure on disk and return
+ *              it in *image_len.
  *
- * Return:	Non-negative on success/Negative on failure
+ * Return:      Non-negative on success/Negative on failure
  *
  * Programmer:  Quincey Koziol
- *              koziol@ncsa.uiuc.edu
- *              May  2 2006
+ *              koziol@hdfgroup.org
+ *              August 14, 2013
  *
  *-------------------------------------------------------------------------
  */
 static herr_t
-H5FS_cache_hdr_flush(H5F_t *f, hid_t dxpl_id, hbool_t destroy, haddr_t addr, H5FS_t *fspace, unsigned H5_ATTR_UNUSED * flags_ptr)
+H5FS__cache_hdr_image_len(const void *_thing, size_t *image_len,
+    hbool_t H5_ATTR_UNUSED *compressed_ptr, size_t H5_ATTR_UNUSED *compressed_image_len_ptr)
 {
-    H5WB_t      *wb = NULL;             /* Wrapped buffer for header data */
-    uint8_t     hdr_buf[H5FS_HDR_BUF_SIZE]; /* Buffer for header */
-    herr_t ret_value = SUCCEED;         /* Return value */
+    const H5FS_t *fspace = (const H5FS_t *)_thing;       /* Pointer to the object */
+
+    FUNC_ENTER_STATIC_NOERR
+
+    /* Check arguments */
+    HDassert(fspace);
+    HDassert(fspace->cache_info.magic == H5C__H5C_CACHE_ENTRY_T_MAGIC);
+    HDassert(fspace->cache_info.type == H5AC_FSPACE_HDR);
+    HDassert(image_len);
+
+    /* Set the image length size */
+    *image_len = fspace->hdr_size;
+
+    FUNC_LEAVE_NOAPI(SUCCEED)
+} /* end H5FS__cache_hdr_image_len() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:	H5FS__cache_hdf_pre_serialize
+ *
+ * Purpose:	The free space manager header contains the address, size, and 
+ *		allocation size of the free space manager section info.  However,
+ *		since it is possible for the section info to either not be allocated
+ *		at all, or be allocated in temporary (AKA imaginary) files space,
+ *		it is possible for the above mentioned fields to contain giberish
+ *		when the free space manager header is serialized.
+ *
+ *		This function exists to prevent this problem.  It does so by 
+ *		forcing allocation of real file space for the section information.
+ *
+ *		Note that in the Version 2 cache, this problem was dealt with by
+ *		simply flushing the section info before flushing the header.  This
+ *		was possible, since the clients handled file I/O directly.  As 
+ *		this responsibility has moved to the cache in Version 3, this 
+ *		solution is no longer directly applicable.
+ *
+ * Return:	Success:	SUCCEED
+ *		Failure:	FAIL
+ *
+ * Programmer:	John Mainzer
+ *		6/21/14
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t 
+H5FS__cache_hdr_pre_serialize(const H5F_t *f, hid_t dxpl_id, void *_thing,
+    haddr_t addr, size_t H5_ATTR_UNUSED len, size_t H5_ATTR_UNUSED compressed_len, 
+    haddr_t *new_addr, size_t *new_len, size_t H5_ATTR_UNUSED *new_compressed_len, 
+    unsigned *flags)
+{
+    H5FS_t 	*fspace = (H5FS_t *)_thing;     /* Pointer to the object */
+    herr_t     	 ret_value = SUCCEED;           /* Return value */
 
-    FUNC_ENTER_NOAPI_NOINIT
+    FUNC_ENTER_STATIC_TAG(dxpl_id, H5AC__FREESPACE_TAG, FAIL)
 
-    /* check arguments */
+    /* Sanity check */
     HDassert(f);
-    HDassert(H5F_addr_defined(addr));
     HDassert(fspace);
-    HDassert(H5F_addr_defined(fspace->addr));
+    HDassert(fspace->cache_info.magic == H5C__H5C_CACHE_ENTRY_T_MAGIC);
+    HDassert(fspace->cache_info.type == H5AC_FSPACE_HDR);
+    HDassert(H5F_addr_defined(addr));
+    HDassert(new_addr);
+    HDassert(new_len);
+    HDassert(flags);
 
-    /* Check if the header "owns" the section info */
     if(fspace->sinfo) {
-        /* Sanity check - should not be trying to destroy header if it still
-         *      "owns" section info
+        /* This implies that the header "owns" the section info.  
+         *
+         * Unfortunately, the comments in the code are not clear as to 
+	 * what this means, but from reviewing the code (most particularly
+         * H5FS_close(), H5FS_sinfo_lock, and H5FS_sinfo_unlock()), I 
+         * gather that it means that the header is maintaining a pointer to 
+         * an instance of H5FS_sinfo_t in which free space data is 
+         * maintained, and either:
+         *
+         * 1) The instance of H5FS_sinfo_t is not in the metadata cache.
+         *
+         *    This will be TRUE iff H5F_addr_defined(fspace->sect_addr) 
+         *    is FALSE, and fspace->sinfo is not NULL.  This is sometimes
+         *    referred to as "floating" section info in the comments.
+         *
+         *    If the section info structure contains free space data 
+         *    that must be placed on disk eventually, then 
+         *
+         *        fspace->serial_sect_count > 0
+         *
+         *    and
+         *
+         *        H5F_addr_defined(fspace->addr)
+         *
+         *    will both be TRUE.  If this contition does not hold, then
+         *    either the free space info is not persistant 
+         *    (!H5F_addr_defined(fspace->addr)???) or the section info 
+         *    contains no free space data that must be written to file 
+         *    ( fspace->serial_sect_count == 0 ).
+         *
+         * 2) The instance of H5FS_sinfo_t is in the metadata cache with
+         *    address in temporary file space (AKA imaginary file space).
+         *    The entry may or may not be protected, and if protected, it 
+         *    may be protected either RW or RO (as indicated by 
+         *    fspace->sinfo_protected and  fspace->sinfo_accmod).
+         *
+         * 3) The instance of H5FS_sinfo_t is in the metadata cache with
+         *    address in real file space.  As in case 2) above, the entry
+         *    may or may not be protected, and if protected, it 
+         *    may be protected either RW or RO (as indicated by 
+         *    fspace->sinfo_protected and  fspace->sinfo_accmod).
+         *
+         * Observe that fspace->serial_sect_count > 0 must be TRUE in 
+         * cases 2) and 3), as the section info should not be stored on 
+         * disk if it doesn't exist.  Similarly, since the section info
+         * will not be stored to disk unless the header is, 
+         * H5F_addr_defined(fspace->addr) must hold as well.
+	 *
+         * As the objective is to touch up the free space manager header
+         * so that it contains sensical data on the size and location of 
+         * the section information, we have to handle each of the above
+         * cases differently.
+         *
+         * Case 1) If either fspace->serial_sect_count == 0 or 
+         *         ! H5F_addr_defined(fspace->addr) do nothing as either 
+         *         the free space manager data is not persistant, or the 
+         *         section info is empty.
+         *
+         *         Otherwise, allocate space for the section info in real
+         *         file space, insert the section info at this location, and 
+         *         set fspace->sect_addr, fspace->sect_size, and 
+         *	   fspace->alloc_sect_size to reflect the new location
+         *	   of the section info.  Note that it is not necessary to
+         *         force a write of the section info.
+         *
+         * Case 2) Allocate space for the section info in real file space,
+         *         and tell the metadata cache to relocate the entry.  
+         *         Update fspace->sect_addr, fspace->sect_size, and 
+         *         fspace->alloc_sect_size to reflect the new location.
+         *
+         * Case 3) Nothing to be done in this case, although it is useful
+         *         to perform sanity checks.
+         *
+         * Note that while we may alter the contents of the free space 
+         * header in cases 1) and 2), there is no need to mark the header 
+         * as dirty, as the metadata cache would not be attempting to 
+         * serialize the header if it though it was clean.
          */
-        HDassert(!destroy);
-
-        /* Check if the section info is dirty */
-        if(fspace->sinfo->dirty) {
-            if(fspace->serial_sect_count > 0) {
-                /* Check if we need to allocate space for  section info */
-                if(H5F_IS_TMP_ADDR(f, fspace->sect_addr) || !H5F_addr_defined(fspace->sect_addr)) {
-                    /* Sanity check */
-                    HDassert(fspace->sect_size > 0);
-
-                    /* Allocate space for the section info in file */
-                    if(HADDR_UNDEF == (fspace->sect_addr = H5MF_alloc(f, H5FD_MEM_FSPACE_SINFO, dxpl_id, fspace->sect_size)))
-                        HGOTO_ERROR(H5E_FSPACE, H5E_NOSPACE, FAIL, "file allocation failed for free space sections")
-                    fspace->alloc_sect_size = (size_t)fspace->sect_size;
-
-                    /* Mark header dirty */
-                    /* (don't use cache API, since we're in a callback) */
-                    fspace->cache_info.is_dirty = TRUE;
-                } /* end if */
-
-                /* Write section info to file */
-                if(H5FS_cache_sinfo_flush(f, dxpl_id, FALSE, fspace->sect_addr, fspace->sinfo, NULL) < 0)
-                    HGOTO_ERROR(H5E_FSPACE, H5E_CANTFLUSH, FAIL, "unable to save free space section info to disk")
+        if(fspace->serial_sect_count > 0 && H5F_addr_defined(fspace->addr)) {
+	    /* Sanity check */
+            HDassert(fspace->sect_size > 0);
+
+            if(!H5F_addr_defined(fspace->sect_addr)) { /* case 1 */
+		/* allocate file space for the section info, and insert it
+                 * into the metadata cache.
+                 */
+                if(HADDR_UNDEF == (fspace->sect_addr = H5MF_alloc((H5F_t *)f, H5FD_MEM_FSPACE_SINFO, dxpl_id, fspace->sect_size)))
+                    HGOTO_ERROR(H5E_FSPACE, H5E_NOSPACE, FAIL, "file allocation failed for free space sections")
+
+                fspace->alloc_sect_size = (size_t)fspace->sect_size;
+		if(H5AC_insert_entry((H5F_t *)f, dxpl_id, H5AC_FSPACE_SINFO, fspace->sect_addr, fspace->sinfo, H5AC__NO_FLAGS_SET) < 0)
+                    HGOTO_ERROR(H5E_FSPACE, H5E_CANTINIT, FAIL, "can't add free space sections to cache")
+
+                HDassert(fspace->sinfo->cache_info.size == fspace->alloc_sect_size);
+
+                /* the metadata cache is now managing the section info, 
+                 * so set fspace->sinfo to NULL.
+                 */
+                fspace->sinfo = NULL;
             } /* end if */
-
-            /* Mark section info clean */
-            fspace->sinfo->dirty = FALSE;
-        } /* end if */
+            else if(H5F_IS_TMP_ADDR(f, fspace->sect_addr)) { /* case 2 */
+                haddr_t new_sect_addr;
+
+		/* move the section info from temporary (AKA imaginary) file
+                 * space to real file space.
+                 */
+
+                /* if my reading of the code is correct, this should always
+                 * be the case.  If not, we will have to add code to resize
+                 * file space allocation for section info as well as moving it.
+                 */
+                HDassert(fspace->sect_size > 0);
+                HDassert(fspace->alloc_sect_size == (size_t)fspace->sect_size);
+
+                /* Allocate space for the section info in file */
+                if(HADDR_UNDEF == (new_sect_addr = H5MF_alloc((H5F_t *)f, H5FD_MEM_FSPACE_SINFO, dxpl_id, fspace->sect_size)))
+                    HGOTO_ERROR(H5E_FSPACE, H5E_NOSPACE, FAIL, "file allocation failed for free space sections")
+
+                fspace->alloc_sect_size = (size_t)fspace->sect_size;
+                HDassert(fspace->sinfo->cache_info.size == fspace->alloc_sect_size);
+
+                /* Let the metadata cache know the section info moved */
+                if(H5AC_move_entry((H5F_t *)f, H5AC_FSPACE_SINFO, fspace->sect_addr, new_sect_addr) < 0)
+                    HGOTO_ERROR(H5E_HEAP, H5E_CANTMOVE, FAIL, "unable to move section info")
+
+                fspace->sect_addr = new_sect_addr;
+            } /* end else-if */
+            else { /* case 3 -- nothing to do but sanity checking */
+                /* if my reading of the code is correct, this should always
+                 * be the case.  If not, we will have to add code to resize
+                 * file space allocation for section info.
+                 */
+                HDassert(fspace->sect_size > 0);
+                HDassert(fspace->alloc_sect_size == (size_t)fspace->sect_size);
+            } /* end else */
+        } /* end else */
+        else {
+            /* for one reason or another (see comment above) there should
+             * not be any file space allocated for the section info.
+             */
+	    HDassert(!H5F_addr_defined(fspace->sect_addr));
+        } /* end else */
     } /* end if */
-    else if(fspace->serial_sect_count > 0)
-	/* Sanity check that section info has address */
-	HDassert(H5F_addr_defined(fspace->sect_addr));
+    else if(H5F_addr_defined(fspace->sect_addr)) {
+        /* Here the metadata cache is managing the section info.  
+         *
+         * Do some sanity checks, and then test to see if the section 
+         * info is in real file space.  If it isn't relocate it into 
+         * real file space lest the header be written to file with 
+         * a nonsense section info address.
+         */
+        HDassert(fspace->serial_sect_count > 0);
+        HDassert(fspace->sect_size > 0);
+        HDassert(fspace->alloc_sect_size == (size_t)fspace->sect_size);
+
+        if(H5F_IS_TMP_ADDR(f, fspace->sect_addr)) {
+            unsigned sect_status = 0;
+            haddr_t new_sect_addr;
+
+	    /* we have work to do -- must relocate section info into 
+             * real file space.
+             *
+             * Since the section info address is in temporary space (AKA
+             * imaginary space), it follows that the entry must be in 
+             * cache.  Further, since fspace->sinfo is NULL, it must be 
+             * unprotected and un-pinned.  Start by verifying this.
+             */
+            if(H5AC_get_entry_status(f, fspace->sect_addr, &sect_status) < 0)
+                HGOTO_ERROR(H5E_FSPACE, H5E_CANTGET, FAIL, "can't get section info status")
+
+            HDassert(sect_status & H5AC_ES__IN_CACHE);
+            HDassert((sect_status & H5AC_ES__IS_PROTECTED) == 0);
+            HDassert((sect_status & H5AC_ES__IS_PINNED) == 0);
 
-    if(fspace->cache_info.is_dirty) {
-        uint8_t	*hdr;                   /* Pointer to header buffer */
-        uint8_t *p;                     /* Pointer into raw data buffer */
-        uint32_t metadata_chksum;       /* Computed metadata checksum value */
+            /* Allocate space for the section info in file */
+            if(HADDR_UNDEF == (new_sect_addr = H5MF_alloc((H5F_t *)f, H5FD_MEM_FSPACE_SINFO, dxpl_id, fspace->sect_size)))
+                HGOTO_ERROR(H5E_FSPACE, H5E_NOSPACE, FAIL, "file allocation failed for free space sections")
 
-        /* Wrap the local buffer for serialized header info */
-        if(NULL == (wb = H5WB_wrap(hdr_buf, sizeof(hdr_buf))))
-            HGOTO_ERROR(H5E_FSPACE, H5E_CANTINIT, FAIL, "can't wrap buffer")
+            fspace->alloc_sect_size = (size_t)fspace->sect_size;
 
-        /* Get a pointer to a buffer that's large enough for header */
-        if(NULL == (hdr = (uint8_t *)H5WB_actual(wb, fspace->hdr_size)))
-            HGOTO_ERROR(H5E_FSPACE, H5E_NOSPACE, FAIL, "can't get actual buffer")
+            /* Sanity check */
+            HDassert(!H5F_addr_eq(fspace->sect_addr, new_sect_addr));
 
-        /* Get temporary pointer to header */
-        p = hdr;
+            /* Let the metadata cache know the section info moved */
+            if(H5AC_move_entry((H5F_t *)f, H5AC_FSPACE_SINFO, fspace->sect_addr, new_sect_addr) < 0)
+                HGOTO_ERROR(H5E_FSPACE, H5E_CANTMOVE, FAIL, "unable to move section info")
 
-        /* Magic number */
-        HDmemcpy(p, H5FS_HDR_MAGIC, (size_t)H5_SIZEOF_MAGIC);
-        p += H5_SIZEOF_MAGIC;
+            /* Update the internal address for the section info */
+            fspace->sect_addr = new_sect_addr;
 
-        /* Version # */
-        *p++ = H5FS_HDR_VERSION;
+            /* No need to mark the header dirty, as we are about to 
+             * serialize it.
+             */
+        } /* end if */
+    } /* end else-if */
+    else {      /* there is no section info at present */
+        /* do some sanity checks */
+        HDassert(fspace->serial_sect_count == 0);
+        HDassert(fspace->tot_sect_count == fspace->ghost_sect_count);
+    } /* end else */
 
-        /* Client ID */
-        *p++ = fspace->client;
+    /* what ever happened above, set *flags to 0 */
+    *flags = 0;
 
-        /* Total space tracked */
-        H5F_ENCODE_LENGTH(f, p, fspace->tot_space);
+done:
+    FUNC_LEAVE_NOAPI_TAG(ret_value, FAIL)
+} /* end H5FS__cache_hdr_pre_serialize() */
 
-        /* Total # of free space sections tracked */
-        H5F_ENCODE_LENGTH(f, p, fspace->tot_sect_count);
+
+/*-------------------------------------------------------------------------
+ * Function:    H5FS__cache_hdr_serialize
+ *
+ * Purpose: 	Given an instance of H5FS_t and a suitably sized buffer,
+ *      	serialize the contents of the instance of H5FS_t and write
+ *      	its contents to the buffer.  This buffer will be used to 
+ *      	write the image of the instance to file.
+ *
+ * Return:      Success:        SUCCEED
+ *              Failure:        FAIL
+ *
+ * Programmer:  John Mainzer
+ *              6/21/14
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+H5FS__cache_hdr_serialize(const H5F_t *f, void *_image, size_t len,
+    void *_thing)
+{
+    H5FS_t     *fspace = (H5FS_t *)_thing;      /* Pointer to the object */
+    uint8_t    *image = (uint8_t *)_image;      /* Pointer into raw data buffer */
+    uint32_t    metadata_chksum;       /* Computed metadata checksum value */
+    herr_t      ret_value = SUCCEED;   /* Return value */
 
-        /* # of serializable free space sections tracked */
-        H5F_ENCODE_LENGTH(f, p, fspace->serial_sect_count);
+    FUNC_ENTER_STATIC_NOERR
 
-        /* # of ghost free space sections tracked */
-        H5F_ENCODE_LENGTH(f, p, fspace->ghost_sect_count);
+    /* Check arguments */
+    HDassert(f);
+    HDassert(image);
+    HDassert(fspace);
+    HDassert(fspace->cache_info.magic == H5C__H5C_CACHE_ENTRY_T_MAGIC);
+    HDassert(fspace->cache_info.type == H5AC_FSPACE_HDR);
+    HDassert(fspace->hdr_size == len);
+
+    /* The section information does not always exits, and if it does, 
+     * it is not always in the cache.  To make matters more interesting, 
+     * even if it is in the cache, it may not be in real file space.
+     *
+     * The pre-serialize function should have moved the section info 
+     * into real file space if necessary before this function was called.
+     * The following asserts are a cursory check on this.
+     */
+    HDassert((! H5F_addr_defined(fspace->sect_addr)) || (! H5F_IS_TMP_ADDR(f, fspace->sect_addr)));
+    HDassert((! H5F_addr_defined(fspace->sect_addr)) || 
+             ((fspace->serial_sect_count > 0) && 
+              (fspace->sect_size > 0) && 
+              (fspace->alloc_sect_size == (size_t)fspace->sect_size)));
 
-        /* # of section classes */
-        UINT16ENCODE(p, fspace->nclasses);
+    /* Magic number */
+    HDmemcpy(image, H5FS_HDR_MAGIC, (size_t)H5_SIZEOF_MAGIC);
+    image += H5_SIZEOF_MAGIC;
 
-        /* Shrink percent */
-        UINT16ENCODE(p, fspace->shrink_percent);
+    /* Version # */
+    *image++ = H5FS_HDR_VERSION;
 
-        /* Expand percent */
-        UINT16ENCODE(p, fspace->expand_percent);
+    /* Client ID */
+    *image++ = fspace->client;
 
-        /* Size of address space free space sections are within (log2 of actual value) */
-        UINT16ENCODE(p, fspace->max_sect_addr);
+    /* Total space tracked */
+    H5F_ENCODE_LENGTH(f, image, fspace->tot_space);
 
-        /* Max. size of section to track */
-        H5F_ENCODE_LENGTH(f, p, fspace->max_sect_size);
+    /* Total # of free space sections tracked */
+    H5F_ENCODE_LENGTH(f, image, fspace->tot_sect_count);
 
-        /* Address of serialized free space sections */
-        H5F_addr_encode(f, &p, fspace->sect_addr);
+    /* # of serializable free space sections tracked */
+    H5F_ENCODE_LENGTH(f, image, fspace->serial_sect_count);
 
-        /* Size of serialized free space sections */
-        H5F_ENCODE_LENGTH(f, p, fspace->sect_size);
+    /* # of ghost free space sections tracked */
+    H5F_ENCODE_LENGTH(f, image, fspace->ghost_sect_count);
 
-        /* Allocated size of serialized free space sections */
-        H5F_ENCODE_LENGTH(f, p, fspace->alloc_sect_size);
+    /* # of section classes */
+    UINT16ENCODE(image, fspace->nclasses);
 
-        /* Compute checksum */
-        metadata_chksum = H5_checksum_metadata(hdr, (size_t)(p - (uint8_t *)hdr), 0);
+    /* Shrink percent */
+    UINT16ENCODE(image, fspace->shrink_percent);
 
-        /* Metadata checksum */
-        UINT32ENCODE(p, metadata_chksum);
+    /* Expand percent */
+    UINT16ENCODE(image, fspace->expand_percent);
 
-	/* Write the free space header. */
-        HDassert((size_t)(p - hdr) == fspace->hdr_size);
-	if(H5F_block_write(f, H5FD_MEM_FSPACE_HDR, addr, fspace->hdr_size, dxpl_id, hdr) < 0)
-	    HGOTO_ERROR(H5E_FSPACE, H5E_CANTFLUSH, FAIL, "unable to save free space header to disk")
+    /* Size of address space free space sections are within (log2 of 
+     * actual value) 
+     */
+    UINT16ENCODE(image, fspace->max_sect_addr);
 
-	fspace->cache_info.is_dirty = FALSE;
-    } /* end if */
+    /* Max. size of section to track */
+    H5F_ENCODE_LENGTH(f, image, fspace->max_sect_size);
 
-    if(destroy)
-        if(H5FS_cache_hdr_dest(f, fspace) < 0)
-	    HGOTO_ERROR(H5E_FSPACE, H5E_CANTFREE, FAIL, "unable to destroy free space header")
+    /* Address of serialized free space sections */
+    H5F_addr_encode(f, &image, fspace->sect_addr);
 
-done:
-    /* Release resources */
-    if(wb && H5WB_unwrap(wb) < 0)
-        HDONE_ERROR(H5E_FSPACE, H5E_CLOSEERROR, FAIL, "can't close wrapped buffer")
+    /* Size of serialized free space sections */
+    H5F_ENCODE_LENGTH(f, image, fspace->sect_size);
+
+    /* Allocated size of serialized free space sections */
+    H5F_ENCODE_LENGTH(f, image, fspace->alloc_sect_size);
+
+    /* Compute checksum */
+    metadata_chksum = H5_checksum_metadata((uint8_t *)_image, (size_t)(image - (uint8_t *)_image), 0);
+
+    /* Metadata checksum */
+    UINT32ENCODE(image, metadata_chksum);
+
+    /* sanity checks */
+    HDassert((size_t)(image - (uint8_t *)_image) == fspace->hdr_size);
 
     FUNC_LEAVE_NOAPI(ret_value)
-} /* H5FS_cache_hdr_flush() */
+} /* H5FS__cache_hdr_serialize() */
+
+/***************************************/
+/* no H5FS__cache_hdr_notify() function */
+/***************************************/
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5FS_cache_hdr_dest
+ * Function:	H5FS__cache_hdr_free_icr
  *
  * Purpose:	Destroys a free space header in memory.
  *
- * Return:	Non-negative on success/Negative on failure
+ * Note:	The metadata cache sets the object's cache_info.magic to
+ *		H5C__H5C_CACHE_ENTRY_T_BAD_MAGIC before calling a free_icr
+ *		callback (checked in assert).
+ *
+ * Return:	Success:        SUCCEED
+ *              Failure:        FAIL
  *
  * Programmer:	Quincey Koziol
  *		koziol@ncsa.uiuc.edu
@@ -436,175 +733,133 @@ done:
  *-------------------------------------------------------------------------
  */
 static herr_t
-H5FS_cache_hdr_dest(H5F_t *f, H5FS_t *fspace)
+H5FS__cache_hdr_free_icr(void *_thing)
 {
-    herr_t ret_value = SUCCEED; /* Return value */
+    H5FS_t *fspace = (H5FS_t *)_thing;  /* Pointer to the object */
+    herr_t ret_value = SUCCEED;         /* Return value */
 
-    FUNC_ENTER_NOAPI_NOINIT
+    FUNC_ENTER_STATIC
 
-    /* Check arguments */
+    /* Sanity checks */
     HDassert(fspace);
+    HDassert(fspace->cache_info.magic == H5C__H5C_CACHE_ENTRY_T_BAD_MAGIC);
+    HDassert(fspace->cache_info.type == H5AC_FSPACE_HDR);
 
     /* We should not still be holding on to the free space section info */
     HDassert(!fspace->sinfo);
 
-    /* If we're going to free the space on disk, the address must be valid */
-    HDassert(!fspace->cache_info.free_file_space_on_destroy || H5F_addr_defined(fspace->cache_info.addr));
-
-    /* Check for freeing file space for free space header */
-    if(fspace->cache_info.free_file_space_on_destroy) {
-        /* Sanity check */
-        HDassert(H5F_addr_defined(fspace->addr));
-
-        /* Release the space on disk */
-        /* (XXX: Nasty usage of internal DXPL value! -QAK) */
-        if(H5MF_xfree(f, H5FD_MEM_FSPACE_HDR, H5AC_dxpl_id, fspace->cache_info.addr, (hsize_t)fspace->hdr_size) < 0)
-            HGOTO_ERROR(H5E_FSPACE, H5E_CANTFREE, FAIL, "unable to free free space header")
-    } /* end if */
-
     /* Destroy free space header */
     if(H5FS__hdr_dest(fspace) < 0)
         HGOTO_ERROR(H5E_FSPACE, H5E_CANTFREE, FAIL, "unable to destroy free space header")
 
 done:
     FUNC_LEAVE_NOAPI(ret_value)
-} /* end H5FS_cache_hdr_dest() */
+} /* end H5FS__cache_hdr_free_icr() */
 
-
-/*-------------------------------------------------------------------------
- * Function:	H5FS_cache_hdr_clear
- *
- * Purpose:	Mark a free space header in memory as non-dirty.
- *
- * Return:	Non-negative on success/Negative on failure
- *
- * Programmer:	Quincey Koziol
- *		koziol@ncsa.uiuc.edu
- *		May  2 2006
- *
- *-------------------------------------------------------------------------
- */
-static herr_t
-H5FS_cache_hdr_clear(H5F_t *f, H5FS_t *fspace, hbool_t destroy)
-{
-    herr_t ret_value = SUCCEED;         /* Return value */
-
-    FUNC_ENTER_NOAPI_NOINIT
-
-    /*
-     * Check arguments.
-     */
-    HDassert(fspace);
-
-    /* Reset the dirty flag.  */
-    fspace->cache_info.is_dirty = FALSE;
-
-    if(destroy)
-        if(H5FS_cache_hdr_dest(f, fspace) < 0)
-	    HGOTO_ERROR(H5E_FSPACE, H5E_CANTFREE, FAIL, "unable to destroy free space header")
-
-done:
-    FUNC_LEAVE_NOAPI(ret_value)
-} /* end H5FS_cache_hdr_clear() */
+/********************************************************/
+/* metadata cache callback definitions for section info */
+/********************************************************/
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5FS_cache_hdr_size
+ * Function:	H5FS__cache_sinfo_get_load_size()
  *
- * Purpose:	Compute the size in bytes of a free space header
- *		on disk, and return it in *size_ptr.  On failure,
- *		the value of *size_ptr is undefined.
+ * Purpose:	Compute the size of the on disk image of the free space 
+ *		manager section info, and place this value in *image_len.
  *
- * Return:	Non-negative on success/Negative on failure
+ * Return:	Success:	SUCCEED
+ *		Failure:	FAIL
  *
- * Programmer:	Quincey Koziol
- *		koziol@ncsa.uiuc.edu
- *		May  2 2006
+ * Programmer:	John Mainzer
+ *		7/7/14
  *
  *-------------------------------------------------------------------------
  */
-static herr_t
-H5FS_cache_hdr_size(const H5F_t H5_ATTR_UNUSED *f, const H5FS_t *fspace, size_t *size_ptr)
+static herr_t 
+H5FS__cache_sinfo_get_load_size(const void  *_udata, size_t *image_len)
 {
-    FUNC_ENTER_NOAPI_NOINIT_NOERR
+    const H5FS_t 		*fspace;        /* free space manager */
+    const H5FS_sinfo_cache_ud_t *udata = (const H5FS_sinfo_cache_ud_t *)_udata; /* User data for callback */
 
-    /* check arguments */
-    HDassert(f);
+    FUNC_ENTER_STATIC_NOERR
+
+    /* Sanity checks */
+    HDassert(udata);
+    fspace = udata->fspace;
     HDassert(fspace);
-    HDassert(size_ptr);
+    HDassert(fspace->sect_size > 0);
+    HDassert(image_len);
 
-    /* Set size value */
-    *size_ptr = fspace->hdr_size;
+    *image_len = (size_t)(fspace->sect_size);
 
     FUNC_LEAVE_NOAPI(SUCCEED)
-} /* H5FS_cache_hdr_size() */
+} /* end H5FS__cache_sinfo_get_load_size() */
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5FS_cache_sinfo_load
+ * Function:	H5FS__cache_sinfo_deserialize
  *
- * Purpose:	Loads free space sections from the disk.
+ * Purpose:	Given a buffer containing the on disk image of the free space
+ *		manager section info, allocate an instance of H5FS_sinfo_t, load
+ *		it with the data contained in the image, and return a pointer to
+ *		the new instance.
  *
- * Return:      Success:        Pointer to a new free space section info
- *              Failure:        NULL
  *
- * Programmer:  Quincey Koziol
- *              koziol@ncsa.uiuc.edu
- *              July 31 2006
+ * Return:	Success:	Pointer to in core representation
+ *		Failure:	NULL
+ *
+ * Programmer:	John Mainzer
+ *		7/7/14
  *
  *-------------------------------------------------------------------------
  */
-static H5FS_sinfo_t *
-H5FS_cache_sinfo_load(H5F_t *f, hid_t dxpl_id, haddr_t H5_ATTR_UNUSED addr, void *_udata)
+static void *
+H5FS__cache_sinfo_deserialize(const void *_image, size_t len, void *_udata,
+    hbool_t *dirty)
 {
-    H5FS_sinfo_t	*sinfo = NULL;  /* Free space section info */
-    H5FS_sinfo_cache_ud_t *udata = (H5FS_sinfo_cache_ud_t *)_udata; /* user data for callback */
-    haddr_t             fs_addr;        /* Free space header address */
-    size_t              old_sect_size;  /* Old section size */
-    uint8_t		*buf = NULL;    /* Temporary buffer */
-    const uint8_t	*p;             /* Pointer into raw data buffer */
-    uint32_t            stored_chksum;  /* Stored metadata checksum value */
-    uint32_t            computed_chksum; /* Computed metadata checksum value */
-    H5FS_sinfo_t	*ret_value;     /* Return value */
-
-    FUNC_ENTER_NOAPI_NOINIT
-
-    /* Check arguments */
-    HDassert(f);
+    H5FS_sinfo_cache_ud_t  *udata = (H5FS_sinfo_cache_ud_t *)_udata;    /* User data for callback */
+    H5FS_t                 *fspace;         /* free space manager */
+    H5FS_sinfo_t           *sinfo = NULL;   /* Free space section info */
+    haddr_t                 fs_addr;        /* Free space header address */
+    size_t                  old_sect_size;  /* Old section size */
+    const uint8_t          *image = (const uint8_t *)_image;    /* Pointer into raw data buffer */
+    uint32_t                stored_chksum;  /* Stored metadata checksum  */
+    uint32_t                computed_chksum; /* Computed metadata checksum */
+    void *                  ret_value;      /* Return value */
+
+    FUNC_ENTER_STATIC
+
+    /* Sanity checks */
+    HDassert(image);
     HDassert(udata);
+    fspace = udata->fspace;
+    HDassert(fspace);
+    HDassert(fspace->sect_size == len);
+    HDassert(dirty);
 
     /* Allocate a new free space section info */
-    if(NULL == (sinfo = H5FS_sinfo_new(udata->f, udata->fspace)))
-	HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, NULL, "memory allocation failed")
-
-    /* Allocate space for the buffer to serialize the sections into */
-    H5_CHECKED_ASSIGN(old_sect_size, size_t, udata->fspace->sect_size, hsize_t);
-    if(NULL == (buf = H5FL_BLK_MALLOC(sect_block, (size_t)udata->fspace->sect_size)))
+    if(NULL == (sinfo = H5FS_sinfo_new(udata->f, fspace)))
         HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, NULL, "memory allocation failed")
 
-    /* Read buffer from disk */
-    if(H5F_block_read(f, H5FD_MEM_FSPACE_SINFO, udata->fspace->sect_addr, (size_t)udata->fspace->sect_size, dxpl_id, buf) < 0)
-	HGOTO_ERROR(H5E_FSPACE, H5E_READERROR, NULL, "can't read free space sections")
-
-    /* Deserialize free sections from buffer available */
-    p = buf;
+    /* initialize old_sect_size */
+    H5_CHECKED_ASSIGN(old_sect_size, size_t, udata->fspace->sect_size, hsize_t);
 
     /* Magic number */
-    if(HDmemcmp(p, H5FS_SINFO_MAGIC, (size_t)H5_SIZEOF_MAGIC))
-	HGOTO_ERROR(H5E_FSPACE, H5E_CANTLOAD, NULL, "wrong free space sections signature")
-    p += H5_SIZEOF_MAGIC;
+    if(HDmemcmp(image, H5FS_SINFO_MAGIC, (size_t)H5_SIZEOF_MAGIC))
+        HGOTO_ERROR(H5E_FSPACE, H5E_CANTLOAD, NULL, "wrong free space sections signature")
+    image += H5_SIZEOF_MAGIC;
 
     /* Version */
-    if(*p++ != H5FS_SINFO_VERSION)
-	HGOTO_ERROR(H5E_FSPACE, H5E_CANTLOAD, NULL, "wrong free space sections version")
+    if(*image++ != H5FS_SINFO_VERSION)
+        HGOTO_ERROR(H5E_FSPACE, H5E_CANTLOAD, NULL, "wrong free space sections version")
 
     /* Address of free space header for these sections */
-    H5F_addr_decode(udata->f, &p, &fs_addr);
+    H5F_addr_decode(udata->f, &image, &fs_addr);
     if(H5F_addr_ne(fs_addr, udata->fspace->addr))
-	HGOTO_ERROR(H5E_FSPACE, H5E_CANTLOAD, NULL, "incorrect header address for free space sections")
+        HGOTO_ERROR(H5E_FSPACE, H5E_CANTLOAD, NULL, "incorrect header address for free space sections")
 
     /* Check for any serialized sections */
-    if(udata->fspace->serial_sect_count > 0) {
+    if(fspace->serial_sect_count > 0) {
         hsize_t old_tot_sect_count;     /* Total section count from header */
         hsize_t old_serial_sect_count;  /* Total serializable section count from header */
         hsize_t old_ghost_sect_count;   /* Total ghost section count from header */
@@ -615,27 +870,27 @@ H5FS_cache_sinfo_load(H5F_t *f, hid_t dxpl_id, haddr_t H5_ATTR_UNUSED addr, void
         sect_cnt_size = H5VM_limit_enc_size((uint64_t)udata->fspace->serial_sect_count);
 
         /* Reset the section count, the "add" routine will update it */
-        old_tot_sect_count = udata->fspace->tot_sect_count;
-        old_serial_sect_count = udata->fspace->serial_sect_count;
-        old_ghost_sect_count = udata->fspace->ghost_sect_count;
-        old_tot_space = udata->fspace->tot_space;
-        udata->fspace->tot_sect_count = 0;
-        udata->fspace->serial_sect_count = 0;
-        udata->fspace->ghost_sect_count = 0;
-        udata->fspace->tot_space = 0;
-
-        /* Walk through the buffer, deserializing sections */
+        old_tot_sect_count = fspace->tot_sect_count;
+        old_serial_sect_count = fspace->serial_sect_count;
+        old_ghost_sect_count = fspace->ghost_sect_count;
+        old_tot_space = fspace->tot_space;
+        fspace->tot_sect_count = 0;
+        fspace->serial_sect_count = 0;
+        fspace->ghost_sect_count = 0;
+        fspace->tot_space = 0;
+
+        /* Walk through the image, deserializing sections */
         do {
             hsize_t sect_size;      /* Current section size */
             size_t node_count;      /* # of sections of this size */
             size_t u;               /* Local index variable */
 
             /* The number of sections of this node's size */
-            UINT64DECODE_VAR(p, node_count, sect_cnt_size);
+            UINT64DECODE_VAR(image, node_count, sect_cnt_size);
             HDassert(node_count);
 
             /* The size of the sections for this node */
-            UINT64DECODE_VAR(p, sect_size, sinfo->sect_len_size);
+            UINT64DECODE_VAR(image, sect_size, sinfo->sect_len_size);
             HDassert(sect_size);
 
             /* Loop over nodes of this size */
@@ -646,324 +901,306 @@ H5FS_cache_sinfo_load(H5F_t *f, hid_t dxpl_id, haddr_t H5_ATTR_UNUSED addr, void
                 unsigned des_flags;     /* Flags from deserialize callback */
 
                 /* The address of the section */
-                UINT64DECODE_VAR(p, sect_addr, sinfo->sect_off_size);
+                UINT64DECODE_VAR(image, sect_addr, sinfo->sect_off_size);
 
                 /* The type of this section */
-                sect_type = *p++;
+                sect_type = *image++;
 
                 /* Call 'deserialize' callback for this section */
                 des_flags = 0;
                 HDassert(udata->fspace->sect_cls[sect_type].deserialize);
-                if(NULL == (new_sect = (*udata->fspace->sect_cls[sect_type].deserialize)(&udata->fspace->sect_cls[sect_type], udata->dxpl_id, p, sect_addr, sect_size, &des_flags)))
+                if(NULL == (new_sect = (*fspace->sect_cls[sect_type].deserialize) (&fspace->sect_cls[sect_type], udata->dxpl_id, image, sect_addr, sect_size, &des_flags)))
                     HGOTO_ERROR(H5E_FSPACE, H5E_CANTDECODE, NULL, "can't deserialize section")
 
-                /* Update offset in serialization buffer */
-                p += udata->fspace->sect_cls[sect_type].serial_size;
+                /* Update offset in serialization image */
+                image += udata->fspace->sect_cls[sect_type].serial_size;
 
                 /* Insert section in free space manager, unless requested not to */
                 if(!(des_flags & H5FS_DESERIALIZE_NO_ADD))
                     if(H5FS_sect_add(udata->f, udata->dxpl_id, udata->fspace, new_sect, H5FS_ADD_DESERIALIZING, NULL) < 0)
                         HGOTO_ERROR(H5E_FSPACE, H5E_CANTINSERT, NULL, "can't add section to free space manager")
             } /* end for */
-        } while(p < ((buf + old_sect_size) - H5FS_SIZEOF_CHKSUM));
+        } while(image < (((const uint8_t *)_image + old_sect_size) - H5FS_SIZEOF_CHKSUM));
 
         /* Sanity check */
-        HDassert((size_t)(p - buf) == (old_sect_size - H5FS_SIZEOF_CHKSUM));
-        HDassert(old_sect_size == udata->fspace->sect_size);
-        HDassert(old_tot_sect_count == udata->fspace->tot_sect_count);
-        HDassert(old_serial_sect_count == udata->fspace->serial_sect_count);
-        HDassert(old_ghost_sect_count == udata->fspace->ghost_sect_count);
-        HDassert(old_tot_space == udata->fspace->tot_space);
+        HDassert((size_t)(image - (const uint8_t *)_image) == (old_sect_size - H5FS_SIZEOF_CHKSUM));
+        HDassert(old_sect_size == fspace->sect_size);
+        HDassert(old_tot_sect_count == fspace->tot_sect_count);
+        HDassert(old_serial_sect_count == fspace->serial_sect_count);
+        HDassert(old_ghost_sect_count == fspace->ghost_sect_count);
+        HDassert(old_tot_space == fspace->tot_space);
     } /* end if */
 
     /* Compute checksum on indirect block */
-    computed_chksum = H5_checksum_metadata(buf, (size_t)(p - (const uint8_t *)buf), 0);
+    computed_chksum = H5_checksum_metadata((const uint8_t *)_image, (size_t)(image - (const uint8_t *)_image), 0);
 
     /* Metadata checksum */
-    UINT32DECODE(p, stored_chksum);
+    UINT32DECODE(image, stored_chksum);
 
     /* Verify checksum */
     if(stored_chksum != computed_chksum)
-	HGOTO_ERROR(H5E_FSPACE, H5E_BADVALUE, NULL, "incorrect metadata checksum for fractal heap indirect block")
+        HGOTO_ERROR(H5E_FSPACE, H5E_BADVALUE, NULL, "incorrect metadata checksum for fractal heap indirect block")
 
     /* Sanity check */
-    HDassert((size_t)(p - (const uint8_t *)buf) == old_sect_size);
+    HDassert((size_t)(image - (const uint8_t *)_image) == old_sect_size);
 
     /* Set return value */
     ret_value = sinfo;
 
 done:
-    if(buf)
-        buf = H5FL_BLK_FREE(sect_block, buf);
     if(!ret_value && sinfo)
         if(H5FS_sinfo_dest(sinfo) < 0)
             HDONE_ERROR(H5E_FSPACE, H5E_CANTFREE, NULL, "unable to destroy free space info")
 
     FUNC_LEAVE_NOAPI(ret_value)
-} /* end H5FS_cache_sinfo_load() */ /*lint !e818 Can't make udata a pointer to const */
+} /* end H5FS__cache_sinfo_deserialize() */
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5FS_sinfo_serialize_sect_cb
+ * Function:    H5FS__cache_sinfo_image_len
  *
- * Purpose:	Skip list iterator callback to serialize free space sections
- *              of a particular size
+ * Purpose:     Compute the size of the data structure on disk and return
+ *              it in *image_len.
  *
- * Return:	Non-negative on success/Negative on failure
+ * Return:      Non-negative on success/Negative on failure
  *
- * Programmer:	Quincey Koziol
- *              Monday, May  8, 2006
+ * Programmer:  Quincey Koziol
+ *              koziol@hdfgroup.org
+ *              August 14, 2013
  *
  *-------------------------------------------------------------------------
  */
 static herr_t
-H5FS_sinfo_serialize_sect_cb(void *_item, void H5_ATTR_UNUSED *key, void *_udata)
+H5FS__cache_sinfo_image_len(const void *_thing, size_t *image_len,
+    hbool_t H5_ATTR_UNUSED *compressed_ptr, size_t H5_ATTR_UNUSED *compressed_image_len_ptr)
 {
-    H5FS_section_class_t *sect_cls;     /* Class of section */
-    H5FS_section_info_t *sect= (H5FS_section_info_t *)_item;   /* Free space section to work on */
-    H5FS_iter_ud_t *udata = (H5FS_iter_ud_t *)_udata; /* Callback info */
-    herr_t ret_value = SUCCEED;         /* Return value */
-
-    FUNC_ENTER_NOAPI_NOINIT
-
-    /* Check arguments. */
-    HDassert(sect);
-    HDassert(udata->sinfo);
-    HDassert(udata->p);
+    const H5FS_sinfo_t *sinfo = (const H5FS_sinfo_t *)_thing;   /* Pointer to the object */
+    const H5FS_t *fspace;               /* Free space header */
 
-    /* Get section's class */
-    sect_cls = &udata->sinfo->fspace->sect_cls[sect->type];
-
-    /* Check if this section should be serialized (i.e. is not a ghost section) */
-    if(!(sect_cls->flags & H5FS_CLS_GHOST_OBJ)) {
-        /* The address of the section */
-        UINT64ENCODE_VAR(*udata->p, sect->addr, udata->sinfo->sect_off_size);
-
-        /* The type of this section */
-        *(*udata->p)++ = (uint8_t)sect->type;
+    FUNC_ENTER_STATIC_NOERR
 
-        /* Call 'serialize' callback for this section */
-        if(sect_cls->serialize) {
-            if((*sect_cls->serialize)(sect_cls, sect, *udata->p) < 0)
-                HGOTO_ERROR(H5E_FSPACE, H5E_CANTSERIALIZE, FAIL, "can't syncronize section")
+    /* Sanity checks */
+    HDassert(sinfo);
+    HDassert(sinfo->cache_info.magic == H5C__H5C_CACHE_ENTRY_T_MAGIC);
+    HDassert(sinfo->cache_info.type == H5AC_FSPACE_SINFO);
+    fspace = sinfo->fspace;
+    HDassert(fspace);
+    HDassert(fspace->cache_info.magic == H5C__H5C_CACHE_ENTRY_T_MAGIC);
+    HDassert(fspace->cache_info.type == H5AC_FSPACE_HDR);
+    HDassert(image_len);
 
-            /* Update offset in serialization buffer */
-            (*udata->p) += sect_cls->serial_size;
-        } /* end if */
-        else
-            HDassert(sect_cls->serial_size == 0);
-    } /* end if */
+    /* Set the image length size */
+    H5_CHECKED_ASSIGN(*image_len, size_t, sinfo->fspace->alloc_sect_size, hsize_t);
 
-done:
-    FUNC_LEAVE_NOAPI(ret_value)
-} /* H5FS_sinfo_serialize_sect_cb() */
+    FUNC_LEAVE_NOAPI(SUCCEED)
+} /* end H5FS__cache_sinfo_image_len() */
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5FS_sinfo_serialize_node_cb
+ * Function:	H5FS__cache_sinfo_pre_serialize
  *
- * Purpose:	Skip list iterator callback to serialize free space sections
- *              in a bin
+ * Purpose:	The objective of this function is to test to see if file space 
+ *		for the section info is located in temporary (AKA imaginary) file 
+ *		space.  If it is, relocate file space for the section info to 
+ *		regular file space.
  *
- * Return:	Non-negative on success/Negative on failure
+ * Return:	Success:	SUCCEED
+ *		Failure:	FAIL
  *
- * Programmer:	Quincey Koziol
- *              Monday, May  8, 2006
+ * Programmer:	John Mainzer
+ *		7/7/14
  *
  *-------------------------------------------------------------------------
  */
-static herr_t
-H5FS_sinfo_serialize_node_cb(void *_item, void H5_ATTR_UNUSED *key, void *_udata)
+static herr_t 
+H5FS__cache_sinfo_pre_serialize(const H5F_t *f, hid_t dxpl_id, void *_thing,
+    haddr_t addr, size_t len, size_t H5_ATTR_UNUSED compressed_len, haddr_t *new_addr,
+    size_t *new_len, size_t H5_ATTR_UNUSED *new_compressed_len, unsigned *flags)
 {
-    H5FS_node_t *fspace_node = (H5FS_node_t *)_item;   /* Free space size node to work on */
-    H5FS_iter_ud_t *udata = (H5FS_iter_ud_t *)_udata; /* Callback info */
-    herr_t ret_value = SUCCEED;         /* Return value */
+    H5FS_sinfo_t 	*sinfo = (H5FS_sinfo_t *)_thing;        /* Pointer to the object */
+    H5FS_t 		*fspace;                /* Free space header */
+    haddr_t             sinfo_addr;             /* Address for section info */
+    herr_t              ret_value = SUCCEED;    /* Return value */
 
-    FUNC_ENTER_NOAPI_NOINIT
+    FUNC_ENTER_STATIC
 
-    /* Check arguments. */
-    HDassert(fspace_node);
-    HDassert(udata->sinfo);
-    HDassert(udata->p);
+    /* Sanity checks */
+    HDassert(f);
+    HDassert(sinfo);
+    HDassert(sinfo->cache_info.magic == H5C__H5C_CACHE_ENTRY_T_MAGIC);
+    HDassert(sinfo->cache_info.type == H5AC_FSPACE_SINFO);
+    fspace = sinfo->fspace;
+    HDassert(fspace->cache_info.magic == H5C__H5C_CACHE_ENTRY_T_MAGIC);
+    HDassert(fspace->cache_info.type == H5AC_FSPACE_HDR);
+    HDassert(fspace->cache_info.is_pinned);
+    HDassert(H5F_addr_defined(addr));
+    HDassert(H5F_addr_eq(fspace->sect_addr, addr));
+    HDassert(fspace->sect_size == len);
+    HDassert(new_addr);
+    HDassert(new_len);
+    HDassert(flags);
 
-    /* Check if this node has any serializable sections */
-    if(fspace_node->serial_count > 0) {
-        /* The number of serializable sections of this node's size */
-        UINT64ENCODE_VAR(*udata->p, fspace_node->serial_count, udata->sect_cnt_size);
+    /* we shouldn't be called if the section info is empty */
+    HDassert(fspace->serial_sect_count > 0);
 
-        /* The size of the sections for this node */
-        UINT64ENCODE_VAR(*udata->p, fspace_node->sect_size, udata->sinfo->sect_len_size);
+    sinfo_addr = addr; /* this will change if we relocate the section data */
 
-        /* Iterate through all the sections of this size */
-        HDassert(fspace_node->sect_list);
-        if(H5SL_iterate(fspace_node->sect_list, H5FS_sinfo_serialize_sect_cb, udata) < 0)
-            HGOTO_ERROR(H5E_FSPACE, H5E_BADITER, FAIL, "can't iterate over section nodes")
+    /* Check for section info at temporary address */
+    if(H5F_IS_TMP_ADDR(f, fspace->sect_addr)) {
+        /* Sanity check */
+        HDassert(fspace->sect_size > 0);
+        HDassert(H5F_addr_eq(fspace->sect_addr, addr));
+
+        /* Allocate space for the section info in file */
+        if(HADDR_UNDEF == (sinfo_addr = H5MF_alloc((H5F_t *)f, H5FD_MEM_FSPACE_SINFO, dxpl_id, fspace->sect_size)))
+            HGOTO_ERROR(H5E_FSPACE, H5E_NOSPACE, FAIL, "file allocation failed for free space sections")
+
+        fspace->alloc_sect_size = (size_t)fspace->sect_size;
+
+        /* Sanity check */
+        HDassert(!H5F_addr_eq(sinfo->fspace->sect_addr, sinfo_addr));
+
+        /* Let the metadata cache know the section info moved */
+        if(H5AC_move_entry((H5F_t *)f, H5AC_FSPACE_SINFO, sinfo->fspace->sect_addr, sinfo_addr) < 0)
+            HGOTO_ERROR(H5E_FSPACE, H5E_CANTMOVE, FAIL, "unable to move section info")
+
+        /* Update the internal address for the section info */
+        sinfo->fspace->sect_addr = sinfo_addr;
+
+        /* Mark free space header as dirty */
+        if(H5AC_mark_entry_dirty(fspace) < 0)
+            HGOTO_ERROR(H5E_FSPACE, H5E_CANTMARKDIRTY, FAIL, "unable to mark free space header as dirty")
+    } /* end if */
+
+    if(!H5F_addr_eq(addr, sinfo_addr)) {
+        *new_addr = sinfo_addr;
+        *flags = H5C__SERIALIZE_MOVED_FLAG;
     } /* end if */
+    else
+        *flags = 0;
 
 done:
     FUNC_LEAVE_NOAPI(ret_value)
-} /* H5FS_sinfo_serialize_node_cb() */
+} /* end H5FS__cache_sinfo_pre_serialize() */
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5FS_cache_sinfo_flush
+ * Function:	H5FS__cache_sinfo_serialize
  *
- * Purpose:	Flushes a dirty free space section info to disk.
+ * Purpose:	Given an instance of H5FS_sinfo_t and a suitably sized buffer,
+ *		serialize the contents of the instance of H5FS_sinfo_t and write 
+ *		its contents to the buffer.  This buffer will be used to write 
+ *		the image of the instance to file.
  *
- * Return:	Non-negative on success/Negative on failure
+ * Return:	Success:	SUCCEED
+ *		Failure:	FAIL
  *
- * Programmer:  Quincey Koziol
- *              koziol@ncsa.uiuc.edu
- *              July 31 2006
+ * Programmer:	John Mainzer
+ *		6/21/14
  *
  *-------------------------------------------------------------------------
  */
-static herr_t
-H5FS_cache_sinfo_flush(H5F_t *f, hid_t dxpl_id, hbool_t destroy, haddr_t addr, H5FS_sinfo_t *sinfo, unsigned H5_ATTR_UNUSED * flags_ptr)
+static herr_t 
+H5FS__cache_sinfo_serialize(const H5F_t *f, void *_image, size_t len,
+    void *_thing)
 {
-    herr_t ret_value = SUCCEED;         /* Return value */
+    H5FS_sinfo_t        *sinfo = (H5FS_sinfo_t *)_thing;        /* Pointer to the object */
+    H5FS_t              *fspace;            /* Free space header */
+    H5FS_iter_ud_t      udata;              /* User data for callbacks */
+    uint8_t             *image = (uint8_t *)_image;     /* Pointer into raw data buffer */
+    uint32_t            metadata_chksum;    /* Computed metadata checksum value */
+    unsigned            bin;                /* Current bin we are on */
+    herr_t              ret_value = SUCCEED; /* Return value */
 
-    FUNC_ENTER_NOAPI_NOINIT
+    FUNC_ENTER_STATIC
 
-    /* check arguments */
+    /* Sanity checks */
     HDassert(f);
-    HDassert(H5F_addr_defined(addr));
+    HDassert(image);
     HDassert(sinfo);
-    HDassert(sinfo->fspace);
-    HDassert(sinfo->fspace->sect_cls);
-
-    if(sinfo->cache_info.is_dirty || sinfo->dirty) {
-        H5FS_iter_ud_t udata;       /* User data for callbacks */
-        uint8_t	*buf = NULL;        /* Temporary raw data buffer */
-        uint8_t *p;                 /* Pointer into raw data buffer */
-        uint32_t metadata_chksum;   /* Computed metadata checksum value */
-        unsigned bin;               /* Current bin we are on */
-
-        /* Sanity check address */
-        if(H5F_addr_ne(addr, sinfo->fspace->sect_addr))
-            HGOTO_ERROR(H5E_FSPACE, H5E_CANTLOAD, FAIL, "incorrect address for free space sections")
+    HDassert(sinfo->cache_info.magic == H5C__H5C_CACHE_ENTRY_T_MAGIC);
+    HDassert(sinfo->cache_info.type == H5AC_FSPACE_SINFO);
+    fspace = sinfo->fspace;
+    HDassert(fspace->cache_info.magic == H5C__H5C_CACHE_ENTRY_T_MAGIC);
+    HDassert(fspace->cache_info.type == H5AC_FSPACE_HDR);
+    HDassert(fspace->cache_info.is_pinned);
+    HDassert(fspace->sect_size == len);
+    HDassert(fspace->sect_cls);
 
-        /* Allocate temporary buffer */
-        if((buf = H5FL_BLK_MALLOC(sect_block, (size_t)sinfo->fspace->sect_size)) == NULL)
-            HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, FAIL, "memory allocation failed")
-
-        p = buf;
-
-        /* Magic number */
-        HDmemcpy(p, H5FS_SINFO_MAGIC, (size_t)H5_SIZEOF_MAGIC);
-        p += H5_SIZEOF_MAGIC;
-
-        /* Version # */
-        *p++ = H5FS_SINFO_VERSION;
-
-        /* Address of free space header for these sections */
-        H5F_addr_encode(f, &p, sinfo->fspace->addr);
-
-        /* Set up user data for iterator */
-        udata.sinfo = sinfo;
-        udata.p = &p;
-        udata.sect_cnt_size = H5VM_limit_enc_size((uint64_t)sinfo->fspace->serial_sect_count);
-
-        /* Iterate over all the bins */
-        for(bin = 0; bin < sinfo->nbins; bin++)
-            /* Check if there are any sections in this bin */
-            if(sinfo->bins[bin].bin_list)
-                /* Iterate over list of section size nodes for bin */
-                if(H5SL_iterate(sinfo->bins[bin].bin_list, H5FS_sinfo_serialize_node_cb, &udata) < 0)
-                    HGOTO_ERROR(H5E_FSPACE, H5E_BADITER, FAIL, "can't iterate over section size nodes")
-
-        /* Compute checksum */
-        metadata_chksum = H5_checksum_metadata(buf, (size_t)(p - buf), 0);
-
-        /* Metadata checksum */
-        UINT32ENCODE(p, metadata_chksum);
-
-        /* Sanity check */
-        HDassert((size_t)(p - buf) == sinfo->fspace->sect_size);
-        HDassert(sinfo->fspace->sect_size <= sinfo->fspace->alloc_sect_size);
-
-        /* Check for section info at temporary address */
-        if(H5F_IS_TMP_ADDR(f, sinfo->fspace->sect_addr)) {
-            /* Sanity check */
-            HDassert(sinfo->fspace->sect_size > 0);
-            HDassert(H5F_addr_eq(sinfo->fspace->sect_addr, addr));
-
-            /* Allocate space for the section info in file */
-            if(HADDR_UNDEF == (addr = H5MF_alloc(f, H5FD_MEM_FSPACE_SINFO, dxpl_id, sinfo->fspace->sect_size)))
-                HGOTO_ERROR(H5E_FSPACE, H5E_NOSPACE, FAIL, "file allocation failed for free space sections")
-            sinfo->fspace->alloc_sect_size = (size_t)sinfo->fspace->sect_size;
+    /* Magic number */
+    HDmemcpy(image, H5FS_SINFO_MAGIC, (size_t)H5_SIZEOF_MAGIC);
+    image += H5_SIZEOF_MAGIC;
 
-            /* Sanity check */
-            HDassert(!H5F_addr_eq(sinfo->fspace->sect_addr, addr));
+    /* Version # */
+    *image++ = H5FS_SINFO_VERSION;
 
-            /* Let the metadata cache know the section info moved */
-            if(H5AC_move_entry(f, H5AC_FSPACE_SINFO, sinfo->fspace->sect_addr, addr) < 0)
-                HGOTO_ERROR(H5E_HEAP, H5E_CANTMOVE, FAIL, "unable to move indirect block")
+    /* Address of free space header for these sections */
+    H5F_addr_encode(f, &image, sinfo->fspace->addr);
 
-            /* Update the internal address for the section info */
-            sinfo->fspace->sect_addr = addr;
+    /* Set up user data for iterator */
+    udata.sinfo = sinfo;
+    udata.image = &image;
+    udata.sect_cnt_size = H5VM_limit_enc_size((uint64_t)sinfo->fspace->serial_sect_count);
 
-            /* Mark free space header as dirty */
-            if(H5AC_mark_entry_dirty(sinfo->fspace) < 0)
-                HGOTO_ERROR(H5E_FSPACE, H5E_CANTMARKDIRTY, FAIL, "unable to mark free space header as dirty")
-        } /* end if */
+    /* Iterate over all the bins */
+    for(bin = 0; bin < sinfo->nbins; bin++)
+        /* Check if there are any sections in this bin */
+        if(sinfo->bins[bin].bin_list)
+            /* Iterate over list of section size nodes for bin */
+            if(H5SL_iterate(sinfo->bins[bin].bin_list, H5FS__sinfo_serialize_node_cb, &udata) < 0)
+                HGOTO_ERROR(H5E_FSPACE, H5E_BADITER, FAIL, "can't iterate over section size nodes")
 
-        /* Write buffer to disk */
-        if(H5F_block_write(f, H5FD_MEM_FSPACE_SINFO, sinfo->fspace->sect_addr, (size_t)sinfo->fspace->sect_size, dxpl_id, buf) < 0)
-            HGOTO_ERROR(H5E_FSPACE, H5E_CANTFLUSH, FAIL, "unable to save free space sections to disk")
 
-        buf = H5FL_BLK_FREE(sect_block, buf);
+    /* Compute checksum */
+    metadata_chksum = H5_checksum_metadata(_image, (size_t)(image - (uint8_t *)_image), 0);
 
-	sinfo->cache_info.is_dirty = FALSE;
-        sinfo->dirty = FALSE;
-    } /* end if */
+    /* Metadata checksum */
+    UINT32ENCODE(image, metadata_chksum);
 
-    if(destroy)
-        if(H5FS_cache_sinfo_dest(f, sinfo) < 0)
-	    HGOTO_ERROR(H5E_FSPACE, H5E_CANTFREE, FAIL, "unable to destroy free space section info")
+    /* Sanity check */
+    HDassert((size_t)(image - (uint8_t *)_image) == sinfo->fspace->sect_size);
+    HDassert(sinfo->fspace->sect_size <= sinfo->fspace->alloc_sect_size);
 
 done:
     FUNC_LEAVE_NOAPI(ret_value)
-} /* H5FS_cache_sinfo_flush() */
+} /* end H5FS__cache_sinfo_serialize() */
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5FS_cache_sinfo_dest
+ * Function:	H5FS__cache_sinfo_free_icr
  *
- * Purpose:	Destroys a free space section info in memory.
+ * Purpose:	Free the memory used for the in core representation of the 
+ *		free space manager section info.
  *
- * Return:	Non-negative on success/Negative on failure
+ * Note:	The metadata cache sets the object's cache_info.magic to
+ *		H5C__H5C_CACHE_ENTRY_T_BAD_MAGIC before calling a free_icr
+ *		callback (checked in assert).
  *
- * Programmer:	Quincey Koziol
- *		koziol@ncsa.uiuc.edu
- *		July 31 2006
+ * Return:	Success:	SUCCEED
+ *		Failure:	FAIL
+ *
+ * Programmer:	John Mainzer
+ *		6/21/14
  *
  *-------------------------------------------------------------------------
  */
-static herr_t
-H5FS_cache_sinfo_dest(H5F_t *f, H5FS_sinfo_t *sinfo)
+static herr_t 
+H5FS__cache_sinfo_free_icr(void *_thing)
 {
-    herr_t ret_value = SUCCEED; /* Return value */
+    H5FS_sinfo_t        *sinfo = (H5FS_sinfo_t *)_thing;    /* Pointer to the object */
+    H5FS_t              *fspace;                /* Free space header */
+    herr_t              ret_value = SUCCEED;    /* Return value */
 
-    FUNC_ENTER_NOAPI_NOINIT
+    FUNC_ENTER_STATIC
 
-    /* Check arguments */
+    /* Sanity checks */
     HDassert(sinfo);
-
-    /* If we're going to free the space on disk, the address must be valid */
-    HDassert(!sinfo->cache_info.free_file_space_on_destroy || H5F_addr_defined(sinfo->cache_info.addr));
-
-    /* Check for freeing file space for free space section info */
-    if(sinfo->cache_info.free_file_space_on_destroy) {
-        /* Sanity check */
-        HDassert(sinfo->fspace->alloc_sect_size > 0);
-
-        /* Release the space on disk */
-        /* (XXX: Nasty usage of internal DXPL value! -QAK) */
-        if(!H5F_IS_TMP_ADDR(f, sinfo->cache_info.addr))
-            if(H5MF_xfree(f, H5FD_MEM_FSPACE_SINFO, H5AC_dxpl_id, sinfo->cache_info.addr, (hsize_t)sinfo->fspace->alloc_sect_size) < 0)
-                HGOTO_ERROR(H5E_FSPACE, H5E_CANTFREE, FAIL, "unable to free free space section info")
-    } /* end if */
+    HDassert(sinfo->cache_info.magic == H5C__H5C_CACHE_ENTRY_T_BAD_MAGIC);
+    HDassert(sinfo->cache_info.type == H5AC_FSPACE_SINFO);
+    fspace = sinfo->fspace;
+    HDassert(fspace->cache_info.magic == H5C__H5C_CACHE_ENTRY_T_MAGIC);
+    HDassert(fspace->cache_info.type == H5AC_FSPACE_HDR);
+    HDassert(fspace->cache_info.is_pinned);
 
     /* Destroy free space info */
     if(H5FS_sinfo_dest(sinfo) < 0)
@@ -971,73 +1208,107 @@ H5FS_cache_sinfo_dest(H5F_t *f, H5FS_sinfo_t *sinfo)
 
 done:
     FUNC_LEAVE_NOAPI(ret_value)
-} /* end H5FS_cache_sinfo_dest() */
+} /* end H5FS__cache_sinfo_free_icr() */
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5FS_cache_sinfo_clear
+ * Function:	H5FS__sinfo_serialize_sect_cb
  *
- * Purpose:	Mark a free space section info in memory as non-dirty.
+ * Purpose:	Skip list iterator callback to serialize free space sections
+ *              of a particular size
  *
  * Return:	Non-negative on success/Negative on failure
  *
  * Programmer:	Quincey Koziol
- *		koziol@ncsa.uiuc.edu
- *		July 31 2006
+ *              Monday, May  8, 2006
  *
  *-------------------------------------------------------------------------
  */
 static herr_t
-H5FS_cache_sinfo_clear(H5F_t *f, H5FS_sinfo_t *sinfo, hbool_t destroy)
+H5FS__sinfo_serialize_sect_cb(void *_item, void H5_ATTR_UNUSED *key, void *_udata)
 {
+    H5FS_section_class_t *sect_cls;     /* Class of section */
+    H5FS_section_info_t *sect= (H5FS_section_info_t *)_item;   /* Free space section to work on */
+    H5FS_iter_ud_t *udata = (H5FS_iter_ud_t *)_udata; /* Callback info */
     herr_t ret_value = SUCCEED;         /* Return value */
 
-    FUNC_ENTER_NOAPI_NOINIT
+    FUNC_ENTER_STATIC
 
-    /*
-     * Check arguments.
-     */
-    HDassert(sinfo);
+    /* Check arguments. */
+    HDassert(sect);
+    HDassert(udata->sinfo);
+    HDassert(udata->image);
 
-    /* Reset the dirty flag.  */
-    sinfo->cache_info.is_dirty = FALSE;
+    /* Get section's class */
+    sect_cls = &udata->sinfo->fspace->sect_cls[sect->type];
 
-    if(destroy)
-        if(H5FS_cache_sinfo_dest(f, sinfo) < 0)
-	    HGOTO_ERROR(H5E_FSPACE, H5E_CANTFREE, FAIL, "unable to destroy free space section info")
+    /* Check if this section should be serialized (i.e. is not a ghost section) */
+    if(!(sect_cls->flags & H5FS_CLS_GHOST_OBJ)) {
+        /* The address of the section */
+        UINT64ENCODE_VAR(*udata->image, sect->addr, udata->sinfo->sect_off_size);
+
+        /* The type of this section */
+        *(*udata->image)++ = (uint8_t)sect->type;
+
+        /* Call 'serialize' callback for this section */
+        if(sect_cls->serialize) {
+            if((*sect_cls->serialize)(sect_cls, sect, *udata->image) < 0)
+                HGOTO_ERROR(H5E_FSPACE, H5E_CANTSERIALIZE, FAIL, "can't syncronize section")
+
+            /* Update offset in serialization buffer */
+            (*udata->image) += sect_cls->serial_size;
+        } /* end if */
+        else
+            HDassert(sect_cls->serial_size == 0);
+    } /* end if */
 
 done:
     FUNC_LEAVE_NOAPI(ret_value)
-} /* end H5FS_cache_sinfo_clear() */
+} /* H5FS__sinfo_serialize_sect_cb() */
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5FS_cache_sinfo_size
+ * Function:	H5FS__sinfo_serialize_node_cb
  *
- * Purpose:	Compute the size in bytes of a free space section info
- *		on disk, and return it in *size_ptr.  On failure,
- *		the value of *size_ptr is undefined.
+ * Purpose:	Skip list iterator callback to serialize free space sections
+ *              in a bin
  *
  * Return:	Non-negative on success/Negative on failure
  *
  * Programmer:	Quincey Koziol
- *		koziol@ncsa.uiuc.edu
- *		July 31 2006
+ *              Monday, May  8, 2006
  *
  *-------------------------------------------------------------------------
  */
 static herr_t
-H5FS_cache_sinfo_size(const H5F_t H5_ATTR_UNUSED *f, const H5FS_sinfo_t *sinfo, size_t *size_ptr)
+H5FS__sinfo_serialize_node_cb(void *_item, void H5_ATTR_UNUSED *key, void *_udata)
 {
-    FUNC_ENTER_NOAPI_NOINIT_NOERR
+    H5FS_node_t *fspace_node = (H5FS_node_t *)_item;   /* Free space size node to work on */
+    H5FS_iter_ud_t *udata = (H5FS_iter_ud_t *)_udata; /* Callback info */
+    herr_t ret_value = SUCCEED;         /* Return value */
 
-    /* check arguments */
-    HDassert(sinfo);
-    HDassert(size_ptr);
+    FUNC_ENTER_STATIC
+
+    /* Check arguments. */
+    HDassert(fspace_node);
+    HDassert(udata->sinfo);
+    HDassert(udata->image);
 
-    /* Set size value */
-    H5_CHECKED_ASSIGN(*size_ptr, size_t, sinfo->fspace->alloc_sect_size, hsize_t);
+    /* Check if this node has any serializable sections */
+    if(fspace_node->serial_count > 0) {
+        /* The number of serializable sections of this node's size */
+        UINT64ENCODE_VAR(*udata->image, fspace_node->serial_count, udata->sect_cnt_size);
 
-    FUNC_LEAVE_NOAPI(SUCCEED)
-} /* H5FS_cache_sinfo_size() */
+        /* The size of the sections for this node */
+        UINT64ENCODE_VAR(*udata->image, fspace_node->sect_size, udata->sinfo->sect_len_size);
+
+        /* Iterate through all the sections of this size */
+        HDassert(fspace_node->sect_list);
+        if(H5SL_iterate(fspace_node->sect_list, H5FS__sinfo_serialize_sect_cb, udata) < 0)
+            HGOTO_ERROR(H5E_FSPACE, H5E_BADITER, FAIL, "can't iterate over section nodes")
+    } /* end if */
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* H5FS__sinfo_serialize_node_cb() */
 
diff --git a/src/H5FSdbg.c b/src/H5FSdbg.c
index b180efd..de66ebd 100644
--- a/src/H5FSdbg.c
+++ b/src/H5FSdbg.c
@@ -121,7 +121,7 @@ H5FS_debug(H5F_t *f, hid_t dxpl_id, haddr_t addr, FILE *stream, int indent, int
     /*
      * Load the free space header.
      */
-    if(NULL == (fspace = (H5FS_t *)H5AC_protect(f, dxpl_id, H5AC_FSPACE_HDR, addr, &cache_udata, H5AC_READ)))
+    if(NULL == (fspace = (H5FS_t *)H5AC_protect(f, dxpl_id, H5AC_FSPACE_HDR, addr, &cache_udata, H5AC__READ_ONLY_FLAG)))
 	HGOTO_ERROR(H5E_FSPACE, H5E_CANTLOAD, FAIL, "unable to load free space header")
 
     /* Print opening message */
@@ -263,7 +263,7 @@ H5FS_sects_debug(H5F_t *f, hid_t dxpl_id, haddr_t H5_ATTR_UNUSED addr, FILE *str
     /*
      * Load the free space header.
      */
-    if(NULL == (fspace = (H5FS_t *)H5AC_protect(f, dxpl_id, H5AC_FSPACE_HDR, fs_addr, &cache_udata, H5AC_READ)))
+    if(NULL == (fspace = (H5FS_t *)H5AC_protect(f, dxpl_id, H5AC_FSPACE_HDR, fs_addr, &cache_udata, H5AC__READ_ONLY_FLAG)))
 	HGOTO_ERROR(H5E_FSPACE, H5E_CANTLOAD, FAIL, "unable to load free space header")
 
     /* Retrieve the client id */
diff --git a/src/H5FSpkg.h b/src/H5FSpkg.h
index 78afde8..2c1eba7 100644
--- a/src/H5FSpkg.h
+++ b/src/H5FSpkg.h
@@ -182,7 +182,9 @@ struct H5FS_t {
     unsigned sinfo_lock_count;  /* # of times the section info has been locked */
     hbool_t sinfo_protected;    /* Whether the section info was protected when locked */
     hbool_t sinfo_modified;     /* Whether the section info has been modified while locked */
-    H5AC_protect_t sinfo_accmode; /* Access mode for protecting the section info */
+    unsigned sinfo_accmode;     /* Access mode for protecting the section info */
+                                /* must be either H5C__NO_FLAGS_SET (i.e r/w)  */
+				/* or H5AC__READ_ONLY_FLAG (i.e. r/o).         */
     size_t max_cls_serial_size; /* Max. additional size of serialized form of section */
     hsize_t    threshold;      	/* Threshold for alignment              */
     hsize_t    alignment;      	/* Alignment                            */
diff --git a/src/H5FSsection.c b/src/H5FSsection.c
index 8fe4075..0b47f51 100644
--- a/src/H5FSsection.c
+++ b/src/H5FSsection.c
@@ -204,7 +204,7 @@ done:
  *-------------------------------------------------------------------------
  */
 static herr_t
-H5FS_sinfo_lock(H5F_t *f, hid_t dxpl_id, H5FS_t *fspace, H5AC_protect_t accmode)
+H5FS_sinfo_lock(H5F_t *f, hid_t dxpl_id, H5FS_t *fspace, unsigned accmode)
 {
     H5FS_sinfo_cache_ud_t cache_udata; /* User-data for cache callback */
     herr_t ret_value = SUCCEED;    /* Return value */
@@ -220,14 +220,21 @@ HDfprintf(stderr, "%s: fspace->alloc_sect_size = %Hu, fspace->sect_size = %Hu\n"
     HDassert(f);
     HDassert(fspace);
 
+    /* only H5AC__READ_ONLY_FLAG may appear in accmode */
+    HDassert((accmode & (unsigned)(~H5AC__READ_ONLY_FLAG)) == 0);
+
     /* If the free space header doesn't already "own" the section info, load
      *  section info or create it
      */
     if(fspace->sinfo) {
         /* Check if the section info was protected & we want a different access mode */
+
+        /* only H5AC__READ_ONLY_FLAG may appear in fspace->sinfo_accmode */
+        HDassert(((fspace->sinfo_accmode) & (unsigned)(~H5AC__READ_ONLY_FLAG)) == 0);
+
         if(fspace->sinfo_protected && accmode != fspace->sinfo_accmode) {
             /* Check if we need to switch from read-only access to read-write */
-            if(H5AC_WRITE == accmode) {
+	    if(0 == (accmode & (unsigned)(~H5AC__READ_ONLY_FLAG))) {
                 /* Unprotect the read-only section info */
                 if(H5AC_unprotect(f, dxpl_id, H5AC_FSPACE_SINFO, fspace->sect_addr, fspace->sinfo, H5AC__NO_FLAGS_SET) < 0)
                     HGOTO_ERROR(H5E_FSPACE, H5E_CANTUNPROTECT, FAIL, "unable to release free space section info")
@@ -236,11 +243,11 @@ HDfprintf(stderr, "%s: fspace->alloc_sect_size = %Hu, fspace->sect_size = %Hu\n"
                 cache_udata.f = f;
                 cache_udata.dxpl_id = dxpl_id;
                 cache_udata.fspace = fspace;
-                if(NULL == (fspace->sinfo = (H5FS_sinfo_t *)H5AC_protect(f, dxpl_id, H5AC_FSPACE_SINFO, fspace->sect_addr, &cache_udata, H5AC_WRITE)))
+                if(NULL == (fspace->sinfo = (H5FS_sinfo_t *)H5AC_protect(f, dxpl_id, H5AC_FSPACE_SINFO, fspace->sect_addr, &cache_udata, H5AC__NO_FLAGS_SET)))
                     HGOTO_ERROR(H5E_FSPACE, H5E_CANTPROTECT, FAIL, "unable to load free space sections")
 
                 /* Switch the access mode we have */
-                fspace->sinfo_accmode = H5AC_WRITE;
+                fspace->sinfo_accmode = H5AC__NO_FLAGS_SET;
             } /* end if */
         } /* end if */
     } /* end if */
@@ -331,7 +338,7 @@ HDfprintf(stderr, "%s: fspace->alloc_sect_size = %Hu, fspace->sect_size = %Hu\n"
     /* Check if we modified any section */
     if(modified) {
         /* Check if the section info was protected with a different access mode */
-        if(fspace->sinfo_protected && fspace->sinfo_accmode != H5AC_WRITE)
+        if(fspace->sinfo_protected && (0 != ((fspace->sinfo_accmode) & H5AC__READ_ONLY_FLAG)))
             HGOTO_ERROR(H5E_FSPACE, H5E_CANTDIRTY, FAIL, "attempt to modify read-only section info")
 
         /* If we modified the section info, mark it dirty */
@@ -915,7 +922,7 @@ H5FS_sect_remove(H5F_t *f, hid_t dxpl_id, H5FS_t *fspace,
     HDassert(sect);
 
     /* Get a pointer to the section info */
-    if(H5FS_sinfo_lock(f, dxpl_id, fspace, H5AC_WRITE) < 0)
+    if(H5FS_sinfo_lock(f, dxpl_id, fspace, H5AC__NO_FLAGS_SET) < 0)
         HGOTO_ERROR(H5E_FSPACE, H5E_CANTGET, FAIL, "can't get section info")
     sinfo_valid = TRUE;
 
@@ -1396,7 +1403,7 @@ HDfprintf(stderr, "%s: *sect = {%a, %Hu, %u, %s}\n", FUNC, sect->addr, sect->siz
     HDassert(sect->size);
 
     /* Get a pointer to the section info */
-    if(H5FS_sinfo_lock(f, dxpl_id, fspace, H5AC_WRITE) < 0)
+    if(H5FS_sinfo_lock(f, dxpl_id, fspace, H5AC__NO_FLAGS_SET) < 0)
         HGOTO_ERROR(H5E_FSPACE, H5E_CANTGET, FAIL, "can't get section info")
     sinfo_valid = TRUE;
 
@@ -1494,7 +1501,7 @@ HDfprintf(stderr, "%s: fspace->ghost_sect_count = %Hu\n", FUNC, fspace->ghost_se
         H5FS_section_info_t *sect;      /* Temporary free space section */
 
         /* Get a pointer to the section info */
-        if(H5FS_sinfo_lock(f, dxpl_id, fspace, H5AC_WRITE) < 0)
+        if(H5FS_sinfo_lock(f, dxpl_id, fspace, H5AC__NO_FLAGS_SET) < 0)
             HGOTO_ERROR(H5E_FSPACE, H5E_CANTGET, FAIL, "can't get section info")
         sinfo_valid = TRUE;
 
@@ -1613,7 +1620,7 @@ H5FS_sect_try_merge(H5F_t *f, hid_t dxpl_id, H5FS_t *fspace, H5FS_section_info_t
     HDassert(sect->size);
 
     /* Get a pointer to the section info */
-    if(H5FS_sinfo_lock(f, dxpl_id, fspace, H5AC_WRITE) < 0)
+    if(H5FS_sinfo_lock(f, dxpl_id, fspace, H5AC__NO_FLAGS_SET) < 0)
 	HGOTO_ERROR(H5E_FSPACE, H5E_CANTGET, FAIL, "can't get section info")
     sinfo_valid = TRUE;
     saved_fs_size = sect->size;
@@ -1849,7 +1856,7 @@ HDfprintf(stderr, "%s: fspace->ghost_sect_count = %Hu\n", FUNC, fspace->ghost_se
 #endif /* QAK */
     if(fspace->tot_sect_count > 0) {
         /* Get a pointer to the section info */
-        if(H5FS_sinfo_lock(f, dxpl_id, fspace, H5AC_WRITE) < 0)
+        if(H5FS_sinfo_lock(f, dxpl_id, fspace, H5AC__NO_FLAGS_SET) < 0)
             HGOTO_ERROR(H5E_FSPACE, H5E_CANTGET, FAIL, "can't get section info")
         sinfo_valid = TRUE;
 
@@ -1997,7 +2004,7 @@ HDfprintf(stderr, "%s: fspace->tot_sect_count = %Hu\n", FUNC, fspace->tot_sect_c
         unsigned bin;           /* Current bin we are on */
 
         /* Get a pointer to the section info */
-        if(H5FS_sinfo_lock(f, dxpl_id, fspace, H5AC_READ) < 0)
+        if(H5FS_sinfo_lock(f, dxpl_id, fspace, H5AC__READ_ONLY_FLAG) < 0)
             HGOTO_ERROR(H5E_FSPACE, H5E_CANTGET, FAIL, "can't get section info")
         sinfo_valid = TRUE;
 
@@ -2089,7 +2096,7 @@ H5FS_sect_change_class(H5F_t *f, hid_t dxpl_id, H5FS_t *fspace,
     HDassert(new_class < fspace->nclasses);
 
     /* Get a pointer to the section info */
-    if(H5FS_sinfo_lock(f, dxpl_id, fspace, H5AC_WRITE) < 0)
+    if(H5FS_sinfo_lock(f, dxpl_id, fspace, H5AC__NO_FLAGS_SET) < 0)
         HGOTO_ERROR(H5E_FSPACE, H5E_CANTGET, FAIL, "can't get section info")
     sinfo_valid = TRUE;
 
@@ -2403,7 +2410,7 @@ H5FS_sect_try_shrink_eoa(const H5F_t *f, hid_t dxpl_id, const H5FS_t *fspace, vo
     /* Check arguments. */
     HDassert(fspace);
 
-    if(H5FS_sinfo_lock(f, dxpl_id, fspace, H5AC_WRITE) < 0)
+    if(H5FS_sinfo_lock(f, dxpl_id, fspace, H5AC__NO_FLAGS_SET) < 0)
         HGOTO_ERROR(H5E_FSPACE, H5E_CANTGET, FAIL, "can't get section info")
     sinfo_valid = TRUE;
 
diff --git a/src/H5Fint.c b/src/H5Fint.c
index df8e886..0e77349 100644
--- a/src/H5Fint.c
+++ b/src/H5Fint.c
@@ -803,6 +803,14 @@ H5F_dest(H5F_t *f, hid_t dxpl_id, hbool_t flush)
                         HDONE_ERROR(H5E_CACHE, H5E_CANTFLUSH, FAIL, "unable to flush cache")
             } /* end if */
 
+            /* if it exists, unpin the driver information block cache entry,
+             * since we're about to destroy the cache 
+             */
+            if(f->shared->drvinfo)
+                if(H5AC_unpin_entry(f->shared->drvinfo) < 0)
+                    /* Push error, but keep going*/
+                    HDONE_ERROR(H5E_FSPACE, H5E_CANTUNPIN, FAIL, "unable to unpin drvinfo")
+
             /* Unpin the superblock, since we're about to destroy the cache */
             if(H5AC_unpin_entry(f->shared->sblock) < 0)
                 /* Push error, but keep going*/
diff --git a/src/H5Fpkg.h b/src/H5Fpkg.h
index 9f70e12..175fa88 100644
--- a/src/H5Fpkg.h
+++ b/src/H5Fpkg.h
@@ -81,6 +81,21 @@
 #define H5F_SUPERBLOCK_FIXED_SIZE ( H5F_SIGNATURE_LEN                   \
         + 1) /* superblock version */
 
+/* The H5F_SUPERBLOCK_MINIMAL_VARLEN_SIZE is the minimal amount of super block
+ * variable length data guarnateed to load the sizeof offsets and the sizeof 
+ * lengths fields in all versions of the superblock.
+ *
+ * This is necessary in the V3 cache, as on the initial load, we need to 
+ * get enough of the superblock to determine its version and size so that
+ * the metadata cache can load the correct amount of data from file to 
+ * allow the second deserialization attempt to succeed.
+ *
+ * The value selected will have to be revisited for each new version 
+ * of the super block.  Note that the current value is one byte larger
+ * than it needs to be. 
+ */
+#define H5F_SUPERBLOCK_MINIMAL_VARLEN_SIZE	7
+
 /* Macros for computing variable-size superblock size */
 #define H5F_SUPERBLOCK_VARLEN_SIZE_COMMON                               \
         (2  /* freespace, and root group versions */			\
@@ -113,20 +128,38 @@
         + (sizeof_addr) /* EOF address */                               \
         + (sizeof_addr) /* root group object header address */          \
         + H5F_SIZEOF_CHKSUM) /* superblock checksum (keep this last) */
-#define H5F_SUPERBLOCK_VARLEN_SIZE(v, f) (				\
-        (v == 0 ? H5F_SUPERBLOCK_VARLEN_SIZE_V0(H5F_SIZEOF_ADDR(f), H5F_SIZEOF_SIZE(f)) : 0) \
-        + (v == 1 ? H5F_SUPERBLOCK_VARLEN_SIZE_V1(H5F_SIZEOF_ADDR(f), H5F_SIZEOF_SIZE(f)) : 0) \
-        + (v == 2 ? H5F_SUPERBLOCK_VARLEN_SIZE_V2(H5F_SIZEOF_ADDR(f)) : 0))
+#define H5F_SUPERBLOCK_VARLEN_SIZE(v, sizeof_addr, sizeof_size) (	\
+        (v == 0 ? H5F_SUPERBLOCK_VARLEN_SIZE_V0(sizeof_addr, sizeof_size) : 0) \
+        + (v == 1 ? H5F_SUPERBLOCK_VARLEN_SIZE_V1(sizeof_addr, sizeof_size) : 0) \
+        + (v == 2 ? H5F_SUPERBLOCK_VARLEN_SIZE_V2(sizeof_addr) : 0))
 
 /* Total size of superblock, depends on superblock version */
-#define H5F_SUPERBLOCK_SIZE(v, f) ( H5F_SUPERBLOCK_FIXED_SIZE           \
-        + H5F_SUPERBLOCK_VARLEN_SIZE(v, f))
+#define H5F_SUPERBLOCK_SIZE(s) ( H5F_SUPERBLOCK_FIXED_SIZE              \
+        + H5F_SUPERBLOCK_VARLEN_SIZE((s)->super_vers, (s)->sizeof_addr, (s)->sizeof_size))
 
 
 /* Forward declaration external file cache struct used below (defined in
  * H5Fefc.c) */
 typedef struct H5F_efc_t H5F_efc_t;
 
+/* Structure for passing 'user data' to superblock cache callbacks */
+typedef struct H5F_superblock_cache_ud_t {
+/* IN: */
+    H5F_t *f;               /* Pointer to file */
+    hbool_t ignore_drvrinfo; /* Indicate if the driver info should be ignored */
+/* OUT: */
+    unsigned sym_leaf_k;    /* Symbol table leaf node's 'K' value */
+    unsigned btree_k[H5B_NUM_BTREE_ID]; /* B-tree key values for each type */
+    haddr_t stored_eof;     /* End-of-file in file */
+    hbool_t drvrinfo_removed; /* Indicate if the driver info was removed */
+} H5F_superblock_cache_ud_t;
+
+/* Structure for passing 'user data' to driver info block cache callbacks */
+typedef struct H5F_drvrinfo_cache_ud_t {
+    H5F_t   *f;               /* Pointer to file */
+    haddr_t driver_addr;      /* address of driver info block */
+} H5F_drvrinfo_cache_ud_t;
+
 /* Structure for metadata & "small [raw] data" block aggregation fields */
 struct H5F_blk_aggr_t {
     unsigned long       feature_flag;   /* Feature flag type */
@@ -176,6 +209,8 @@ typedef struct H5F_mtab_t {
 typedef struct H5F_super_t {
     H5AC_info_t cache_info;     /* Cache entry information structure          */
     unsigned    super_vers;     /* Superblock version                         */
+    uint8_t	sizeof_addr;	/* Size of addresses in file                  */
+    uint8_t	sizeof_size;	/* Size of offsets in file                    */
     uint8_t     status_flags;   /* File status flags                          */
     unsigned    sym_leaf_k;     /* Size of leaves in symbol tables            */
     unsigned    btree_k[H5B_NUM_BTREE_ID]; /* B-tree key values for each type */
@@ -197,6 +232,13 @@ typedef struct H5F_super_t {
 struct H5F_file_t {
     H5FD_t	*lf; 		/* Lower level file handle for I/O	*/
     H5F_super_t *sblock;        /* Pointer to (pinned) superblock for file */
+    H5O_drvinfo_t *drvinfo;	/* Pointer to the (pinned) driver info 
+                                 * cache entry.  This field is only defined
+                                 * for older versions of the super block,
+                                 * and then only when a driver information
+                                 * block is present.  At all other times
+                                 * it should be NULL.
+                                 */
     unsigned	nrefs;		/* Ref count for times file is opened	*/
     unsigned	flags;		/* Access Permissions for file          */
     H5F_mtab_t	mtab;		/* File mount table                     */
@@ -283,6 +325,7 @@ H5FL_EXTERN(H5F_t);
 H5FL_EXTERN(H5F_file_t);
 
 H5_DLLVAR const H5AC_class_t H5AC_SUPERBLOCK[1];
+H5_DLLVAR const H5AC_class_t H5AC_DRVRINFO[1];
 
 
 /******************************/
diff --git a/src/H5Fsuper.c b/src/H5Fsuper.c
index 166247a..e83330d 100644
--- a/src/H5Fsuper.c
+++ b/src/H5Fsuper.c
@@ -258,14 +258,21 @@ H5F__super_read(H5F_t *f, hid_t dxpl_id)
 {
     H5P_genplist_t     *dxpl;               /* DXPL object */
     H5F_super_t *       sblock = NULL;      /* Superblock structure */
+    H5F_superblock_cache_ud_t udata;        /* User data for cache callbacks */
+    H5P_genplist_t     *c_plist;            /* File creation property list  */
     unsigned            sblock_flags = H5AC__NO_FLAGS_SET;       /* flags used in superblock unprotect call      */
     haddr_t             super_addr;         /* Absolute address of superblock */
-    H5AC_protect_t      rw;                 /* Read/write permissions for file  */
-    hbool_t             dirtied = FALSE;    /* Bool for sblock protect call                 */
+    haddr_t             eof;                /* End of file address */
+    unsigned      	rw_flags;           /* Read/write permissions for file */
     herr_t              ret_value = SUCCEED; /* Return value */
 
     FUNC_ENTER_PACKAGE_TAG(dxpl_id, H5AC__SUPERBLOCK_TAG, FAIL)
 
+    /* initialize the drvinfo to NULL -- we will overwrite this if there
+     * is a driver information block 
+     */
+    f->shared->drvinfo = NULL;
+
     /* Get the DXPL plist object for DXPL ID */
     if(NULL == (dxpl = (H5P_genplist_t *)H5I_object(dxpl_id)))
         HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "can't get property list")
@@ -284,23 +291,358 @@ H5F__super_read(H5F_t *f, hid_t dxpl_id)
     } /* end if */
 
     /* Determine file intent for superblock protect */
-    if(H5F_INTENT(f) & H5F_ACC_RDWR)
-        rw = H5AC_WRITE;
-    else
-        rw = H5AC_READ;
+
+    /* Must tell cache at protect time that the super block is to be
+     * flushed last (and collectively in the parallel case).
+     */
+    rw_flags = H5AC__FLUSH_LAST_FLAG;
+#ifdef H5_HAVE_PARALLEL
+    rw_flags |= H5C__FLUSH_COLLECTIVELY_FLAG;
+#endif /* H5_HAVE_PARALLEL */
+    if(!(H5F_INTENT(f) & H5F_ACC_RDWR))
+        rw_flags |= H5AC__READ_ONLY_FLAG;
+
+    /* Get the shared file creation property list */
+    if(NULL == (c_plist = (H5P_genplist_t *)H5I_object(f->shared->fcpl_id)))
+        HGOTO_ERROR(H5E_FILE, H5E_BADTYPE, FAIL, "can't get property list")
+
+    /* Make certain we can read the fixed-size portion of the superblock */
+    if(H5F__set_eoa(f, H5FD_MEM_SUPER, 
+              H5F_SUPERBLOCK_FIXED_SIZE + H5F_SUPERBLOCK_MINIMAL_VARLEN_SIZE) < 0)
+        HGOTO_ERROR(H5E_FILE, H5E_CANTSET, FAIL, "set end of space allocation request failed")
+
+    /* Set up the user data for cache callbacks */
+    udata.f = f;
+    udata.ignore_drvrinfo = H5F_HAS_FEATURE(f, H5FD_FEAT_IGNORE_DRVRINFO);
+    udata.sym_leaf_k = 0;
+    if(H5P_get(c_plist, H5F_CRT_BTREE_RANK_NAME, udata.btree_k) < 0)
+        HGOTO_ERROR(H5E_FILE, H5E_CANTGET, FAIL, "unable to get rank for btree internal nodes")
+    udata.stored_eof = HADDR_UNDEF;
+    udata.drvrinfo_removed = FALSE;
 
     /* Look up the superblock */
-    if(NULL == (sblock = (H5F_super_t *)H5AC_protect(f, dxpl_id, H5AC_SUPERBLOCK, (haddr_t)0, &dirtied, rw)))
+    if(NULL == (sblock = (H5F_super_t *)H5AC_protect(f, dxpl_id, H5AC_SUPERBLOCK, (haddr_t)0, &udata, rw_flags)))
         HGOTO_ERROR(H5E_FILE, H5E_CANTPROTECT, FAIL, "unable to load superblock")
 
-    /* Mark the superblock dirty if it was modified during loading or VFD indicated to do so */
-    if((H5AC_WRITE == rw) && (dirtied || H5F_HAS_FEATURE(f, H5FD_FEAT_DIRTY_SBLK_LOAD)))
-        sblock_flags |= H5AC__DIRTIED_FLAG;
-
     /* Pin the superblock in the cache */
     if(H5AC_pin_protected_entry(sblock) < 0)
         HGOTO_ERROR(H5E_FILE, H5E_CANTPIN, FAIL, "unable to pin superblock")
 
+    /* Mark the superblock dirty if it was modified during loading */
+    if(((rw_flags & H5AC__READ_ONLY_FLAG) == 0) && udata.ignore_drvrinfo && udata.drvrinfo_removed) {
+        HDassert(sblock->super_vers < HDF5_SUPERBLOCK_VERSION_2);
+        sblock_flags |= H5AC__DIRTIED_FLAG;
+    } /* end if */
+
+    /* The superblock must be flushed last (and collectively in parallel) */
+    sblock_flags |= H5AC__FLUSH_LAST_FLAG;
+#ifdef H5_HAVE_PARALLEL
+    sblock_flags |= H5AC__FLUSH_COLLECTIVELY_FLAG;
+#endif /* H5_HAVE_PARALLEL */
+
+    /* Check if superblock address is different from base address and adjust
+     * base address and "end of address" address if so.
+     */
+    if(!H5F_addr_eq(super_addr, sblock->base_addr)) {
+        /* Check if the superblock moved earlier in the file */
+        if(H5F_addr_lt(super_addr, sblock->base_addr))
+            udata.stored_eof -= (sblock->base_addr - super_addr);
+        else
+            /* The superblock moved later in the file */
+            udata.stored_eof += (super_addr - sblock->base_addr);
+
+        /* Adjust base address for offsets of the HDF5 data in the file */
+        sblock->base_addr = super_addr;
+
+        /* Set the base address for the file in the VFD now */
+        if(H5F__set_base_addr(f, sblock->base_addr) < 0)
+            HGOTO_ERROR(H5E_FILE, H5E_CANTSET, FAIL, "failed to set base address for file driver")
+
+        /* Indicate that the superblock should be marked dirty */
+        if((rw_flags & H5AC__READ_ONLY_FLAG) == 0)
+            sblock_flags |= H5AC__DIRTIED_FLAG;
+    } /* end if */
+
+    /* Set information in the file's creation property list */
+    if(H5P_set(c_plist, H5F_CRT_SUPER_VERS_NAME, &sblock->super_vers) < 0)
+        HGOTO_ERROR(H5E_FILE, H5E_CANTSET, FAIL, "unable to set superblock version")
+    if(H5P_set(c_plist, H5F_CRT_ADDR_BYTE_NUM_NAME, &sblock->sizeof_addr) < 0)
+        HGOTO_ERROR(H5E_FILE, H5E_CANTSET, FAIL, "unable to set byte number in an address")
+    if(H5P_set(c_plist, H5F_CRT_OBJ_BYTE_NUM_NAME, &sblock->sizeof_size) < 0)
+        HGOTO_ERROR(H5E_FILE, H5E_CANTSET, FAIL, "unable to set byte number for object size")
+
+    /* Handle the B-tree 'K' values */
+    if(sblock->super_vers < HDF5_SUPERBLOCK_VERSION_2) {
+        /* Sanity check */
+        HDassert(udata.sym_leaf_k != 0);
+
+        /* Set the symbol table internal node 'K' value */
+        if(H5P_set(c_plist, H5F_CRT_SYM_LEAF_NAME, &udata.sym_leaf_k) < 0)
+            HGOTO_ERROR(H5E_FILE, H5E_CANTSET, FAIL, "unable to set rank for symbol table leaf nodes")
+        sblock->sym_leaf_k = udata.sym_leaf_k;
+
+        /* Set the B-tree internal node values, etc */
+        if(H5P_set(c_plist, H5F_CRT_BTREE_RANK_NAME, udata.btree_k) < 0)
+            HGOTO_ERROR(H5E_FILE, H5E_CANTSET, FAIL, "unable to set rank for btree internal nodes")
+        HDmemcpy(sblock->btree_k, udata.btree_k, sizeof(unsigned) * (size_t)H5B_NUM_BTREE_ID);
+    } /* end if */
+    else {
+        /* Get the (default) B-tree internal node values, etc */
+        /* (Note: these may be reset in a superblock extension) */
+        if(H5P_get(c_plist, H5F_CRT_BTREE_RANK_NAME, sblock->btree_k) < 0)
+            HGOTO_ERROR(H5E_FILE, H5E_CANTGET, FAIL, "unable to get rank for btree internal nodes")
+        if(H5P_get(c_plist, H5F_CRT_SYM_LEAF_NAME, &sblock->sym_leaf_k) < 0)
+            HGOTO_ERROR(H5E_FILE, H5E_CANTGET, FAIL, "unable to get rank for btree internal nodes")
+    } /* end else */
+
+    /*
+     * The user-defined data is the area of the file before the base
+     * address.
+     */
+    if(H5P_set(c_plist, H5F_CRT_USER_BLOCK_NAME, &sblock->base_addr) < 0)
+        HGOTO_ERROR(H5E_FILE, H5E_CANTSET, FAIL, "unable to set userblock size")
+
+    /*
+     * Make sure that the data is not truncated. One case where this is
+     * possible is if the first file of a family of files was opened
+     * individually.
+     */
+    if(HADDR_UNDEF == (eof = H5FD_get_eof(f->shared->lf, H5FD_MEM_DEFAULT)))
+        HGOTO_ERROR(H5E_FILE, H5E_CANTGET, FAIL, "unable to determine file size")
+
+    /* (Account for the stored EOA being absolute offset -QAK) */
+    if((eof + sblock->base_addr) < udata.stored_eof)
+        HGOTO_ERROR(H5E_FILE, H5E_TRUNCATED, FAIL, "truncated file: eof = %llu, sblock->base_addr = %llu, stored_eoa = %llu", (unsigned long long)eof, (unsigned long long)sblock->base_addr, (unsigned long long)udata.stored_eof)
+
+    /*
+     * Tell the file driver how much address space has already been
+     * allocated so that it knows how to allocate additional memory.
+     */
+
+    /* Decode the optional driver information block */
+    if(H5F_addr_defined(sblock->driver_addr)) {
+        H5O_drvinfo_t *drvinfo;         /* Driver info */
+        H5F_drvrinfo_cache_ud_t drvrinfo_udata;  /* User data for metadata callbacks */
+        unsigned drvinfo_flags = H5AC__NO_FLAGS_SET;    /* Flags used in driver info block unprotect call */
+
+        /* Sanity check - driver info block should only be defined for
+         *      superblock version < 2.
+         */
+        HDassert(sblock->super_vers < HDF5_SUPERBLOCK_VERSION_2);
+
+        /* Set up user data */
+        drvrinfo_udata.f           = f;
+        drvrinfo_udata.driver_addr = sblock->driver_addr;
+
+        /* extend EOA so we can read at least the fixed sized 
+         * portion of the driver info block 
+         */
+        if(H5FD_set_eoa(f->shared->lf, H5FD_MEM_SUPER, sblock->driver_addr + H5F_DRVINFOBLOCK_HDR_SIZE) < 0) /* will extend eoa later if required */ 
+            HGOTO_ERROR(H5E_FILE, H5E_CANTINIT, FAIL, \
+                        "set end of space allocation request failed")
+
+        /* Look up the driver info block */
+        if(NULL == (drvinfo = (H5O_drvinfo_t *)H5AC_protect(f, dxpl_id, H5AC_DRVRINFO, sblock->driver_addr, &drvrinfo_udata, rw_flags)))
+            HGOTO_ERROR(H5E_FILE, H5E_CANTPROTECT, FAIL, "unable to load driver info block")
+
+        /* Loading the driver info block is enough to set up the right info */
+
+        /* Check if we need to rewrite the driver info block info */
+        if ( ( (rw_flags & H5AC__READ_ONLY_FLAG) == 0 ) &&
+             ( H5F_HAS_FEATURE(f, H5FD_FEAT_DIRTY_DRVRINFO_LOAD) ) ) {
+
+            drvinfo_flags |= H5AC__DIRTIED_FLAG;
+        } /* end if */
+
+        /* set the pin entry flag so that the driver information block 
+         * cache entry will be pinned in the cache.
+         */
+        drvinfo_flags |= H5AC__PIN_ENTRY_FLAG;
+
+        /* Release the driver info block */
+        if(H5AC_unprotect(f, dxpl_id, H5AC_DRVRINFO, sblock->driver_addr, drvinfo, drvinfo_flags) < 0)
+            HGOTO_ERROR(H5E_FILE, H5E_CANTUNPROTECT, FAIL, "unable to release driver info block")
+
+        /* save a pointer to the driver information cache entry */
+        f->shared->drvinfo = drvinfo;
+    } /* end if */
+
+    /* (Account for the stored EOA being absolute offset -NAF) */
+    if(H5F__set_eoa(f, H5FD_MEM_SUPER, udata.stored_eof - sblock->base_addr) < 0)
+        HGOTO_ERROR(H5E_FILE, H5E_CANTSET, FAIL, "unable to set end-of-address marker for file")
+
+    /* Decode the optional superblock extension info */
+    if(H5F_addr_defined(sblock->ext_addr)) {
+        H5O_loc_t ext_loc;      /* "Object location" for superblock extension */
+        H5O_btreek_t btreek;    /* v1 B-tree 'K' value message from superblock extension */
+        H5O_drvinfo_t drvinfo;  /* Driver info message from superblock extension */
+	size_t u; 		/* Local index variable */
+        htri_t status;          /* Status for message existing */
+
+        /* Sanity check - superblock extension should only be defined for
+         *      superblock version >= 2.
+         */
+        HDassert(sblock->super_vers >= HDF5_SUPERBLOCK_VERSION_2);
+
+        /* Check for superblock extension being located "outside" the stored
+         *      'eoa' value, which can occur with the split/multi VFD.
+         */
+        if(H5F_addr_gt(sblock->ext_addr, udata.stored_eof)) {
+            /* Set the 'eoa' for the object header memory type large enough
+             *  to give some room for a reasonably sized superblock extension.
+             *  (This is _rather_ a kludge -QAK)
+             */
+            if(H5F__set_eoa(f, H5FD_MEM_OHDR, (haddr_t)(sblock->ext_addr + 1024)) < 0)
+                HGOTO_ERROR(H5E_FILE, H5E_CANTSET, FAIL, "unable to set end-of-address marker for file")
+        } /* end if */
+
+        /* Open the superblock extension */
+	if(H5F_super_ext_open(f, sblock->ext_addr, &ext_loc) < 0)
+            HGOTO_ERROR(H5E_FILE, H5E_CANTOPENOBJ, FAIL, "unable to open file's superblock extension")
+
+        /* Check for the extension having a 'driver info' message */
+        if((status = H5O_msg_exists(&ext_loc, H5O_DRVINFO_ID, dxpl_id)) < 0)
+            HGOTO_ERROR(H5E_FILE, H5E_EXISTS, FAIL, "unable to read object header")
+        if(status) {
+            /* Check for ignoring the driver info for this file */
+            if(!udata.ignore_drvrinfo) {
+
+                /* Retrieve the 'driver info' structure */
+                if(NULL == H5O_msg_read(&ext_loc, H5O_DRVINFO_ID, &drvinfo, dxpl_id))
+                    HGOTO_ERROR(H5E_FILE, H5E_CANTGET, FAIL, "driver info message not present")
+
+                /* Validate and decode driver information */
+                if(H5FD_sb_load(f->shared->lf, drvinfo.name, drvinfo.buf) < 0)
+                    HGOTO_ERROR(H5E_FILE, H5E_CANTDECODE, FAIL, "unable to decode driver information")
+
+                /* Reset driver info message */
+                H5O_msg_reset(H5O_DRVINFO_ID, &drvinfo);
+            } /* end else */
+        } /* end if */
+
+        /* Read in the shared OH message information if there is any */
+        if(H5SM_get_info(&ext_loc, c_plist, dxpl_id) < 0)
+            HGOTO_ERROR(H5E_FILE, H5E_CANTGET, FAIL, "unable to read SOHM table information")
+
+        /* Check for the extension having a 'v1 B-tree "K"' message */
+        if((status = H5O_msg_exists(&ext_loc, H5O_BTREEK_ID, dxpl_id)) < 0)
+            HGOTO_ERROR(H5E_FILE, H5E_EXISTS, FAIL, "unable to read object header")
+        if(status) {
+            /* Retrieve the 'v1 B-tree "K"' structure */
+            if(NULL == H5O_msg_read(&ext_loc, H5O_BTREEK_ID, &btreek, dxpl_id))
+                HGOTO_ERROR(H5E_FILE, H5E_CANTGET, FAIL, "v1 B-tree 'K' info message not present")
+
+            /* Set non-default v1 B-tree 'K' value info from file */
+            sblock->btree_k[H5B_CHUNK_ID] = btreek.btree_k[H5B_CHUNK_ID];
+            sblock->btree_k[H5B_SNODE_ID] = btreek.btree_k[H5B_SNODE_ID];
+            sblock->sym_leaf_k = btreek.sym_leaf_k;
+
+            /* Set non-default v1 B-tree 'K' values in the property list */
+            if(H5P_set(c_plist, H5F_CRT_BTREE_RANK_NAME, btreek.btree_k) < 0)
+                HGOTO_ERROR(H5E_FILE, H5E_CANTSET, FAIL, "unable to set rank for btree internal nodes")
+            if(H5P_set(c_plist, H5F_CRT_SYM_LEAF_NAME, &btreek.sym_leaf_k) < 0)
+                HGOTO_ERROR(H5E_FILE, H5E_CANTSET, FAIL, "unable to set rank for symbol table leaf nodes")
+        } /* end if */
+
+        /* Check for the extension having a 'free-space manager info' message */
+        if((status = H5O_msg_exists(&ext_loc, H5O_FSINFO_ID, dxpl_id)) < 0)
+            HGOTO_ERROR(H5E_FILE, H5E_EXISTS, FAIL, "unable to read object header")
+        if(status) {
+            H5O_fsinfo_t fsinfo;    /* Free-space manager info message from superblock extension */
+
+            /* Retrieve the 'free-space manager info' structure */
+	    if(NULL == H5O_msg_read(&ext_loc, H5O_FSINFO_ID, &fsinfo, dxpl_id))
+                HGOTO_ERROR(H5E_FILE, H5E_CANTGET, FAIL, "unable to get free-space manager info message")
+
+            /* Check for non-default info */
+	    if(f->shared->fs_strategy != fsinfo.strategy) {
+		f->shared->fs_strategy = fsinfo.strategy;
+
+		/* Set non-default strategy in the property list */
+		if(H5P_set(c_plist, H5F_CRT_FILE_SPACE_STRATEGY_NAME, &fsinfo.strategy) < 0)
+		    HGOTO_ERROR(H5E_FILE, H5E_CANTSET, FAIL, "unable to set file space strategy")
+	    } /* end if */
+	    if(f->shared->fs_threshold != fsinfo.threshold) {
+		f->shared->fs_threshold = fsinfo.threshold;
+
+		/* Set non-default threshold in the property list */
+		if(H5P_set(c_plist, H5F_CRT_FREE_SPACE_THRESHOLD_NAME, &fsinfo.threshold) < 0)
+		    HGOTO_ERROR(H5E_FILE, H5E_CANTSET, FAIL, "unable to set file space strategy")
+	    } /* end if */
+
+	    /* Set free-space manager addresses */
+	    f->shared->fs_addr[0] = HADDR_UNDEF;
+	    for(u = 1; u < NELMTS(f->shared->fs_addr); u++)
+		f->shared->fs_addr[u] = fsinfo.fs_addr[u-1];
+        } /* end if */
+
+        /* Close superblock extension */
+        if(H5F_super_ext_close(f, &ext_loc, dxpl_id, FALSE) < 0)
+	    HGOTO_ERROR(H5E_FILE, H5E_CANTCLOSEOBJ, FAIL, "unable to close file's superblock extension")
+    } /* end if */
+
+    /* Update the driver info if VFD indicated to do so */
+    /* (NOTE: only for later versions of superblock, earlier versions are handled
+     *          earlier in this routine.
+     */
+    if(((rw_flags & H5AC__READ_ONLY_FLAG) == 0) &&
+            sblock->super_vers >= HDF5_SUPERBLOCK_VERSION_2 &&
+            H5F_addr_defined(sblock->ext_addr)) {
+        /* Check for modifying the driver info when opening the file */
+        if(H5F_HAS_FEATURE(f, H5FD_FEAT_DIRTY_DRVRINFO_LOAD)) {
+            size_t          driver_size;    /* Size of driver info block (bytes) */
+
+            /* Check for driver info message */
+            H5_CHECKED_ASSIGN(driver_size, size_t, H5FD_sb_size(f->shared->lf), hsize_t);
+            if(driver_size > 0) {
+                H5O_drvinfo_t drvinfo;      /* Driver info */
+                uint8_t dbuf[H5F_MAX_DRVINFOBLOCK_SIZE];  /* Driver info block encoding buffer */
+
+                /* Sanity check */
+                HDassert(driver_size <= H5F_MAX_DRVINFOBLOCK_SIZE);
+
+                /* Encode driver-specific data */
+                if(H5FD_sb_encode(f->shared->lf, drvinfo.name, dbuf) < 0)
+                    HGOTO_ERROR(H5E_FILE, H5E_CANTINIT, FAIL, "unable to encode driver information")
+
+                /* Set the driver info information for the superblock extension */
+                drvinfo.len = driver_size;
+                drvinfo.buf = dbuf;
+
+                /* Write driver info information to the superblock extension */
+
+#if 1 /* bug fix test code -- tidy this up if all goes well */ /* JRM */
+		/* KLUGE ALERT!!
+		 *
+		 * H5F_super_ext_write_msg() expects f->shared->sblock to 
+		 * be set -- verify that it is NULL, and then set it.
+		 * Set it back to NULL when we are done.
+		 */
+		HDassert(f->shared->sblock == NULL);
+		f->shared->sblock = sblock;
+#endif /* JRM */
+
+                if(H5F_super_ext_write_msg(f, dxpl_id, &drvinfo, H5O_DRVINFO_ID, FALSE) < 0)
+                    HGOTO_ERROR(H5E_FILE, H5E_WRITEERROR, FAIL, "error in writing message to superblock extension")
+
+#if 1 /* bug fix test code -- tidy this up if all goes well */ /* JRM */
+		f->shared->sblock = NULL;
+#endif /* JRM */
+
+            } /* end if */
+        } /* end if */
+        /* Check for eliminating the driver info block */
+        else if(H5F_HAS_FEATURE(f, H5FD_FEAT_IGNORE_DRVRINFO)) {
+            /* Remove the driver info message from the superblock extension */
+            if(H5F_super_ext_remove_msg(f, dxpl_id, H5O_DRVINFO_ID) < 0)
+                HGOTO_ERROR(H5E_FILE, H5E_CANTRELEASE, FAIL, "error in removing message from superblock extension")
+
+            /* Check if the superblock extension was removed */
+            if(!H5F_addr_defined(sblock->ext_addr))
+                sblock_flags |= H5AC__DIRTIED_FLAG;
+        } /* end if */
+    } /* end if */
+
     /* Set the pointer to the pinned superblock */
     f->shared->sblock = sblock;
 
@@ -309,6 +651,32 @@ done:
     if(sblock && H5AC_unprotect(f, dxpl_id, H5AC_SUPERBLOCK, (haddr_t)0, sblock, sblock_flags) < 0)
         HDONE_ERROR(H5E_FILE, H5E_CANTUNPROTECT, FAIL, "unable to close superblock")
 
+    /* If we have failed, make sure no entries are left in the 
+     * metadata cache, so that it can be shut down and discarded.
+     */
+    if(ret_value < 0) { 
+        /* Unpin and discard drvinfo cache entry */
+        if(f->shared->drvinfo) {
+            if(H5AC_unpin_entry(f->shared->drvinfo) < 0)
+                HDONE_ERROR(H5E_FILE, H5E_CANTUNPIN, FAIL, "unable to unpin driver info")
+
+            /* Evict the driver info block from the cache */
+            if(H5AC_expunge_entry(f, dxpl_id, H5AC_DRVRINFO, sblock->driver_addr, H5AC__NO_FLAGS_SET) < 0)
+                HDONE_ERROR(H5E_FILE, H5E_CANTEXPUNGE, FAIL, "unable to expunge driver info block")
+        } /* end if */
+
+        /* Unpin & discard superblock */
+        if(sblock) {
+            /* Unpin superblock in cache */
+            if(H5AC_unpin_entry(sblock) < 0)
+                HDONE_ERROR(H5E_FILE, H5E_CANTUNPIN, FAIL, "unable to unpin superblock")
+
+            /* Evict the superblock from the cache */
+            if(H5AC_expunge_entry(f, dxpl_id, H5AC_SUPERBLOCK, (haddr_t)0, H5AC__NO_FLAGS_SET) < 0)
+                HDONE_ERROR(H5E_FILE, H5E_CANTEXPUNGE, FAIL, "unable to expunge superblock")
+        } /* end if */
+    } /* end if */
+
     FUNC_LEAVE_NOAPI_TAG(ret_value, FAIL)
 } /* end H5F__super_read() */
 
@@ -334,6 +702,8 @@ H5F__super_init(H5F_t *f, hid_t dxpl_id)
 {
     H5F_super_t    *sblock = NULL;      /* Superblock cache structure                 */
     hbool_t         sblock_in_cache = FALSE;    /* Whether the superblock has been inserted into the metadata cache */
+    H5O_drvinfo_t  *drvinfo = NULL;     /* Driver info */
+    hbool_t         drvinfo_in_cache = FALSE;   /* Whether the driver info block has been inserted into the metadata cache */
     H5P_genplist_t *plist;              /* File creation property list                */
     hsize_t         userblock_size;     /* Size of userblock, in bytes                */
     hsize_t         superblock_size;    /* Size of superblock, in bytes               */
@@ -427,11 +797,13 @@ H5F__super_init(H5F_t *f, hid_t dxpl_id)
     if(H5F__set_base_addr(f, sblock->base_addr) < 0)
         HGOTO_ERROR(H5E_FILE, H5E_CANTINIT, FAIL, "failed to set base address for file driver")
 
-    /* Save a local copy of the superblock version number */
+    /* Save a local copy of the superblock version number, size of addresses & offsets */
     sblock->super_vers = super_vers;
+    sblock->sizeof_addr = f->shared->sizeof_addr;
+    sblock->sizeof_size = f->shared->sizeof_size;
 
     /* Compute the size of the superblock */
-    superblock_size = (hsize_t)H5F_SUPERBLOCK_SIZE(super_vers, f);
+    superblock_size = (hsize_t)H5F_SUPERBLOCK_SIZE(sblock);
 
     /* Compute the size of the driver information block */
     H5_CHECKED_ASSIGN(driver_size, size_t, H5FD_sb_size(f->shared->lf), hsize_t);
@@ -446,10 +818,10 @@ H5F__super_init(H5F_t *f, hid_t dxpl_id)
     } /* end if */
 
     /*
-     * Allocate space for the userblock, superblock & driver info blocks.
-     * We do it with one allocation request because the userblock and
-     * superblock need to be at the beginning of the file and only the first
-     * allocation request is required to return memory at format address zero.
+     * Allocate space for the superblock & driver info block.
+     * We do it with one allocation request because the superblock needs to be
+     * at the beginning of the file and only the first allocation request is
+     * required to return memory at format address zero.
      */
     if(super_vers < HDF5_SUPERBLOCK_VERSION_2)
         superblock_size += driver_size;
@@ -466,6 +838,9 @@ H5F__super_init(H5F_t *f, hid_t dxpl_id)
     /* Keep a copy of the superblock info */
     f->shared->sblock = sblock;
 
+    /* set the drvinfo filed to NULL -- will overwrite this later if needed */
+    f->shared->drvinfo = NULL;
+
     /*
      * Determine if we will need a superblock extension
      */
@@ -572,6 +947,33 @@ H5F__super_init(H5F_t *f, hid_t dxpl_id)
                 HGOTO_ERROR(H5E_FILE, H5E_CANTINIT, FAIL, "unable to update free-space info header message")
 	} /* end if */
     } /* end if */
+    else {
+        /* Check for creating an "old-style" driver info block */
+        if(driver_size > 0) {
+            /* Sanity check */
+            HDassert(H5F_addr_defined(sblock->driver_addr));
+
+            /* Allocate space for the driver info */
+            if(NULL == (drvinfo = (H5O_drvinfo_t *)H5MM_calloc(sizeof(H5O_drvinfo_t))))
+                HGOTO_ERROR(H5E_FILE, H5E_CANTALLOC, FAIL, "memory allocation failed for driver info message")
+
+            /* Set up driver info message */
+            /* (NOTE: All the actual information (name & driver information) is
+             *          actually based on the VFD info in the file handle and
+             *          will be encoded by the VFD's 'encode' callback, so it
+             *          doesn't need to be set here. -QAK, 7/20/2013
+             */
+            H5_CHECKED_ASSIGN(drvinfo->len, size_t, H5FD_sb_size(f->shared->lf), hsize_t);
+
+            /* Insert driver info block into cache */
+            if(H5AC_insert_entry(f, dxpl_id, H5AC_DRVRINFO, sblock->driver_addr, drvinfo, H5AC__PIN_ENTRY_FLAG | H5AC__FLUSH_LAST_FLAG | H5AC__FLUSH_COLLECTIVELY_FLAG) < 0)
+                HGOTO_ERROR(H5E_FILE, H5E_CANTINS, FAIL, "can't add driver info block to cache")
+            drvinfo_in_cache = TRUE;
+            f->shared->drvinfo = drvinfo;
+        } /* end if */
+        else
+            HDassert(!H5F_addr_defined(sblock->driver_addr));
+    } /* end if */
 
 done:
     /* Close superblock extension, if it was created */
@@ -580,6 +982,23 @@ done:
 
     /* Cleanup on failure */
     if(ret_value < 0) {
+        /* Check if the driver info block has been allocated yet */
+        if(drvinfo) {
+            /* Check if we've cached it already */
+            if(drvinfo_in_cache) {
+                /* Unpin drvinfo in cache */
+                if(H5AC_unpin_entry(drvinfo) < 0)
+                    HDONE_ERROR(H5E_FILE, H5E_CANTUNPIN, FAIL, "unable to unpin driver info")
+
+                /* Evict the driver info block from the cache */
+                if(H5AC_expunge_entry(f, dxpl_id, H5AC_DRVRINFO, sblock->driver_addr, H5AC__NO_FLAGS_SET) < 0)
+                    HDONE_ERROR(H5E_FILE, H5E_CANTEXPUNGE, FAIL, "unable to expunge driver info block")
+            } /* end if */
+            else
+                /* Free driver info block */
+                H5MM_xfree(drvinfo);
+        } /* end if */
+
         /* Check if the superblock has been allocated yet */
         if(sblock) {
             /* Check if we've cached it already */
@@ -635,6 +1054,14 @@ H5F_super_dirty(H5F_t *f)
     if(H5AC_mark_entry_dirty(f->shared->sblock) < 0)
         HGOTO_ERROR(H5E_FILE, H5E_CANTMARKDIRTY, FAIL, "unable to mark superblock as dirty")
 
+    /* if the driver information block exists, mark it dirty as well 
+     * so that the change in eoa will be reflected there as well if 
+     * appropriate.
+     */
+    if ( f->shared->drvinfo )
+        if(H5AC_mark_entry_dirty(f->shared->drvinfo) < 0)
+            HGOTO_ERROR(H5E_FILE, H5E_CANTMARKDIRTY, FAIL, "unable to mark drvinfo as dirty")
+
 done:
     FUNC_LEAVE_NOAPI(ret_value)
 } /* H5F_super_dirty() */
@@ -698,7 +1125,7 @@ H5F__super_size(H5F_t *f, hid_t dxpl_id, hsize_t *super_size, hsize_t *super_ext
 
     /* Set the superblock size */
     if(super_size)
-	*super_size = (hsize_t)H5F_SUPERBLOCK_SIZE(f->shared->sblock->super_vers, f);
+	*super_size = (hsize_t)H5F_SUPERBLOCK_SIZE(f->shared->sblock);
 
     /* Set the superblock extension size */
     if(super_ext_size) {
diff --git a/src/H5Fsuper_cache.c b/src/H5Fsuper_cache.c
index ded845d..cf14770 100644
--- a/src/H5Fsuper_cache.c
+++ b/src/H5Fsuper_cache.c
@@ -51,9 +51,6 @@
 /* Local Macros */
 /****************/
 
-/* Maximum size of super-block buffers */
-#define H5F_MAX_SUPERBLOCK_SIZE  134
-
 
 /******************/
 /* Local Typedefs */
@@ -70,28 +67,70 @@
 /********************/
 
 /* Metadata cache (H5AC) callbacks */
-static H5F_super_t *H5F_sblock_load(H5F_t *f, hid_t dxpl_id, haddr_t addr, void *udata);
-static herr_t H5F_sblock_flush(H5F_t *f, hid_t dxpl_id, hbool_t destroy, haddr_t addr, H5F_super_t *sblock);
-static herr_t H5F_sblock_dest(H5F_t *f, H5F_super_t * sblock);
-static herr_t H5F_sblock_clear(H5F_t *f, H5F_super_t *sblock, hbool_t destroy);
-static herr_t H5F_sblock_size(const H5F_t *f, const H5F_super_t *sblock, size_t *size_ptr);
+static herr_t H5F__cache_superblock_get_load_size(const void *udata, size_t *image_len);
+static void *H5F__cache_superblock_deserialize(const void *image, size_t len,
+    void *udata, hbool_t *dirty);
+static herr_t H5F__cache_superblock_image_len(const void *thing, 
+    size_t *image_len, hbool_t *compressed_ptr, 
+    size_t *compressed_image_len_ptr);
+static herr_t H5F__cache_superblock_pre_serialize(const H5F_t *f, 
+    hid_t dxpl_id, void *thing, haddr_t addr, size_t len, 
+    size_t compressed_len, haddr_t *new_addr, size_t *new_len, 
+    size_t *new_compressed_len, unsigned *flags);
+static herr_t H5F__cache_superblock_serialize(const H5F_t *f, void *image, size_t len,
+    void *thing);
+static herr_t H5F__cache_superblock_free_icr(void *thing);
+
+static herr_t H5F__cache_drvrinfo_get_load_size(const void *udata, size_t *image_len);
+static void *H5F__cache_drvrinfo_deserialize(const void *image, size_t len,
+    void *udata, hbool_t *dirty);
+static herr_t H5F__cache_drvrinfo_image_len(const void *thing, 
+    size_t *image_len, hbool_t *compressed_ptr, 
+    size_t *compressed_image_len_ptr);
+static herr_t H5F__cache_drvrinfo_serialize(const H5F_t *f, void *image, size_t len,
+    void *thing);
+static herr_t H5F__cache_drvrinfo_free_icr(void *thing);
 
 
 /*********************/
 /* Package Variables */
 /*********************/
 
-/* H5F inherits cache-like properties from H5AC */
+/* H5F superblock inherits cache-like properties from H5AC */
 const H5AC_class_t H5AC_SUPERBLOCK[1] = {{
-    H5AC_SUPERBLOCK_ID,
-    (H5AC_load_func_t)H5F_sblock_load,
-    (H5AC_flush_func_t)H5F_sblock_flush,
-    (H5AC_dest_func_t)H5F_sblock_dest,
-    (H5AC_clear_func_t)H5F_sblock_clear,
-    (H5AC_notify_func_t)NULL,
-    (H5AC_size_func_t)H5F_sblock_size,
+    H5AC_SUPERBLOCK_ID,                 /* Metadata client ID */
+    "Superblock",                       /* Metadata client name (for debugging) */
+    H5FD_MEM_SUPER,                     /* File space memory type for client */
+    H5AC__CLASS_SPECULATIVE_LOAD_FLAG,  /* Client class behavior flags */
+    H5F__cache_superblock_get_load_size,/* 'get_load_size' callback */
+    H5F__cache_superblock_deserialize,  /* 'deserialize' callback */
+    H5F__cache_superblock_image_len,    /* 'image_len' callback */
+    H5F__cache_superblock_pre_serialize,/* 'pre_serialize' callback */
+    H5F__cache_superblock_serialize,    /* 'serialize' callback */
+    NULL,                               /* 'notify' callback */
+    H5F__cache_superblock_free_icr,     /* 'free_icr' callback */
+    NULL,				/* 'clear' callback */
+    NULL,                               /* 'fsf_size' callback */
+}};
+
+/* H5F driver info block inherits cache-like properties from H5AC */
+const H5AC_class_t H5AC_DRVRINFO[1] = {{
+    H5AC_DRVRINFO_ID,                   /* Metadata client ID */
+    "Driver info block",                /* Metadata client name (for debugging) */
+    H5FD_MEM_SUPER,                     /* File space memory type for client */
+    H5AC__CLASS_SPECULATIVE_LOAD_FLAG,  /* Client class behavior flags */
+    H5F__cache_drvrinfo_get_load_size,  /* 'get_load_size' callback */
+    H5F__cache_drvrinfo_deserialize,    /* 'deserialize' callback */
+    H5F__cache_drvrinfo_image_len,      /* 'image_len' callback */
+    NULL,                               /* 'pre_serialize' callback */
+    H5F__cache_drvrinfo_serialize,      /* 'serialize' callback */
+    NULL,                               /* 'notify' callback */
+    H5F__cache_drvrinfo_free_icr,       /* 'free_icr' callback */
+    NULL,				/* 'clear' callback */
+    NULL,                               /* 'fsf_size' callback */
 }};
 
+
 /*****************************/
 /* Library Private Variables */
 /*****************************/
@@ -107,546 +146,470 @@ H5FL_EXTERN(H5F_super_t);
 
 
 /*-------------------------------------------------------------------------
- * Function:    H5F_sblock_load
+ * Function:    H5F__cache_superblock_get_load_size
  *
- * Purpose:     Loads the superblock from the file, and deserializes
- *              its information into the H5F_super_t structure.
+ * Purpose:     Compute the size of the data structure on disk.
  *
- * Return:      Success:        SUCCEED
- *              Failure:        NULL
+ * Return:      Non-negative on success/Negative on failure
  *
- * Programmer:  Mike McGreevy
- *              mamcgree@hdfgroup.org
- *              April 8, 2009
+ * Programmer:  Quincey Koziol
+ *              koziol@hdfgroup.org
+ *              July 17, 2013
  *
  *-------------------------------------------------------------------------
  */
-static H5F_super_t *
-H5F_sblock_load(H5F_t *f, hid_t dxpl_id, haddr_t H5_ATTR_UNUSED addr, void *_udata)
+static herr_t
+H5F__cache_superblock_get_load_size(const void H5_ATTR_UNUSED *udata, size_t *image_len)
 {
-    H5F_super_t        *sblock = NULL;      /* File's superblock */
-    haddr_t             base_addr = HADDR_UNDEF;        /* Base address of file */
-    uint8_t             sbuf[H5F_MAX_SUPERBLOCK_SIZE];     /* Buffer for superblock */
-    H5P_genplist_t     *dxpl;               /* DXPL object */
-    H5P_genplist_t     *c_plist;            /* File creation property list  */
-    H5F_file_t         *shared;             /* shared part of `file'        */
-    H5FD_t             *lf;                 /* file driver part of `shared' */
-    haddr_t             stored_eof;         /* stored end-of-file address in file  */
-    haddr_t             eof;                /* end of file address           */
-    uint8_t             sizeof_addr;        /* Size of offsets in the file (in bytes) */
-    uint8_t             sizeof_size;        /* Size of lengths in the file (in bytes) */
-    const size_t        fixed_size = H5F_SUPERBLOCK_FIXED_SIZE; /*fixed sizeof superblock   */
-    size_t              variable_size;      /*variable sizeof superblock    */
-    uint8_t            *p;                  /* Temporary pointer into encoding buffer */
-    unsigned            super_vers;         /* Superblock version          */
-    hbool_t            *dirtied = (hbool_t *)_udata;  /* Set up dirtied out value */
-    H5F_super_t        *ret_value;          /* Return value */
-
-    FUNC_ENTER_NOAPI_NOINIT
+    FUNC_ENTER_STATIC_NOERR
 
     /* Check arguments */
-    HDassert(f);
-    HDassert(H5F_addr_eq(addr, 0));
-    HDassert(dirtied);
+    HDassert(image_len);
 
-    /* Short cuts */
-    shared = f->shared;
-    lf = shared->lf;
+    /* Set the initial image length size */
+    *image_len = H5F_SUPERBLOCK_FIXED_SIZE +    /* Fixed size of superblock */
+        H5F_SUPERBLOCK_MINIMAL_VARLEN_SIZE;
 
-    /* Get the shared file creation property list */
-    if(NULL == (c_plist = (H5P_genplist_t *)H5I_object(shared->fcpl_id)))
-        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, NULL, "can't get property list")
+    FUNC_LEAVE_NOAPI(SUCCEED)
+} /* end H5F__cache_superblock_get_load_size() */
 
-    /* Get the base address for the file in the VFD */
-    if(HADDR_UNDEF == (base_addr = H5FD_get_base_addr(lf)))
-        HGOTO_ERROR(H5E_FILE, H5E_CANTGET, NULL, "failed to get base address for file driver")
+
+/*-------------------------------------------------------------------------
+ * Function:	H5F__cache_superblock_deserialize
+ *
+ * Purpose:	Loads an object from the disk.
+ *
+ * Return:	Success:	Pointer to new object
+ *		Failure:	NULL
+ *
+ * Programmer:	Quincey Koziol
+ *		koziol@hdfgroup.org
+ *		July 18 2013
+ *
+ *-------------------------------------------------------------------------
+ */
+static void *
+H5F__cache_superblock_deserialize(const void *_image, size_t len, void *_udata,
+    hbool_t H5_ATTR_UNUSED *dirty)
+{
+    H5F_super_t         *sblock = NULL; /* File's superblock */
+    H5F_superblock_cache_ud_t *udata = (H5F_superblock_cache_ud_t *)_udata; /* User data */
+    const uint8_t	*image = (const uint8_t *)_image;       /* Pointer into raw data buffer */
+    size_t              variable_size;  /* Sariable size of superblock */
+    unsigned            super_vers;     /* Superblock version */
+    uint8_t             sizeof_addr;    /* Size of offsets in the file (in bytes) */
+    uint8_t             sizeof_size;    /* Size of lengths in the file (in bytes) */
+    H5F_super_t         *ret_value;     /* Return value */
+
+    FUNC_ENTER_STATIC
+
+    /* Check arguments */
+    HDassert(image);
+    HDassert(udata);
+    HDassert(udata->f);
 
     /* Allocate space for the superblock */
     if(NULL == (sblock = H5FL_CALLOC(H5F_super_t)))
         HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, NULL, "memory allocation failed")
 
-    /* The superblock must be flushed last (and collectively in parallel) */
-    sblock->cache_info.flush_me_last = TRUE;
-#ifdef H5_HAVE_PARALLEL
-    sblock->cache_info.flush_me_collectively = TRUE;
-#endif
-
-    /* Get the DXPL plist object for DXPL ID */
-    if(NULL == (dxpl = (H5P_genplist_t *)H5I_object(dxpl_id)))
-        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, NULL, "can't get property list")
-
-    /* Read fixed-size portion of the superblock */
-    p = sbuf;
-    H5_CHECK_OVERFLOW(fixed_size, size_t, haddr_t);
-    if(H5FD_set_eoa(lf, H5FD_MEM_SUPER, (haddr_t)fixed_size) < 0)
-        HGOTO_ERROR(H5E_FILE, H5E_CANTINIT, NULL, "set end of space allocation request failed")
-    if(H5FD_read(lf, dxpl, H5FD_MEM_SUPER, (haddr_t)0, fixed_size, p) < 0)
-        HGOTO_ERROR(H5E_FILE, H5E_READERROR, NULL, "unable to read superblock")
-
     /* Skip over signature (already checked when locating the superblock) */
-    p += H5F_SIGNATURE_LEN;
+    image += H5F_SIGNATURE_LEN;
 
     /* Superblock version */
-    super_vers = *p++;
+    super_vers = *image++;
     if(super_vers > HDF5_SUPERBLOCK_VERSION_LATEST)
         HGOTO_ERROR(H5E_FILE, H5E_BADVALUE, NULL, "bad superblock version number")
-    if(H5P_set(c_plist, H5F_CRT_SUPER_VERS_NAME, &super_vers) < 0)
-        HGOTO_ERROR(H5E_PLIST, H5E_CANTSET, NULL, "unable to set superblock version")
 
     /* Record the superblock version */
     sblock->super_vers = super_vers;
 
     /* Sanity check */
-    HDassert(((size_t)(p - sbuf)) == fixed_size);
+    HDassert(((size_t)(image - (const uint8_t *)_image)) == H5F_SUPERBLOCK_FIXED_SIZE);
+    HDassert(len >= H5F_SUPERBLOCK_FIXED_SIZE + 6);
+
+    /* Determine the size of addresses & size of offsets, for computing the
+     * variable-sized portion of the superblock.
+     */
+    if(super_vers < HDF5_SUPERBLOCK_VERSION_2) {
+        sizeof_addr = image[4];
+        sizeof_size = image[5];
+    } /* end if */
+    else {
+        sizeof_addr = image[0];
+        sizeof_size = image[1];
+    } /* end else */
+    if(sizeof_addr != 2 && sizeof_addr != 4 &&
+            sizeof_addr != 8 && sizeof_addr != 16 && sizeof_addr != 32)
+        HGOTO_ERROR(H5E_FILE, H5E_BADVALUE, NULL, "bad byte number in an address")
+    if(sizeof_size != 2 && sizeof_size != 4 &&
+            sizeof_size != 8 && sizeof_size != 16 && sizeof_size != 32)
+        HGOTO_ERROR(H5E_FILE, H5E_BADVALUE, NULL, "bad byte number for object size")
+    sblock->sizeof_addr = sizeof_addr;
+    sblock->sizeof_size = sizeof_size;
 
     /* Determine the size of the variable-length part of the superblock */
-    variable_size = (size_t)H5F_SUPERBLOCK_VARLEN_SIZE(super_vers, f);
+    variable_size = (size_t)H5F_SUPERBLOCK_VARLEN_SIZE(super_vers, sizeof_addr, sizeof_size);
     HDassert(variable_size > 0);
-    HDassert(fixed_size + variable_size <= sizeof(sbuf));
 
-    /* Read in variable-sized portion of superblock */
-    if(H5FD_set_eoa(lf, H5FD_MEM_SUPER, (haddr_t)(fixed_size + variable_size)) < 0)
-        HGOTO_ERROR(H5E_FILE, H5E_CANTINIT, NULL, "set end of space allocation request failed")
-    if(H5FD_read(lf, dxpl, H5FD_MEM_SUPER, (haddr_t)fixed_size, variable_size, p) < 0)
-        HGOTO_ERROR(H5E_FILE, H5E_CANTOPENFILE, NULL, "unable to read superblock")
+    /* Handle metadata cache retry for variable-sized portion of the superblock */
+    if(len != (H5F_SUPERBLOCK_FIXED_SIZE + variable_size)) {
+        /* Sanity check */
+        HDassert(len == (H5F_SUPERBLOCK_FIXED_SIZE + H5F_SUPERBLOCK_MINIMAL_VARLEN_SIZE));
 
-    /* Check for older version of superblock format */
-    if(super_vers < HDF5_SUPERBLOCK_VERSION_2) {
-        uint32_t	status_flags;	    /* File status flags	   */
-        unsigned        btree_k[H5B_NUM_BTREE_ID];  /* B-tree internal node 'K' values */
-        unsigned        sym_leaf_k;         /* Symbol table leaf node's 'K' value */
-
-        /* Freespace version (hard-wired) */
-        if(HDF5_FREESPACE_VERSION != *p++)
-            HGOTO_ERROR(H5E_FILE, H5E_BADVALUE, NULL, "bad free space version number")
-
-        /* Root group version number (hard-wired) */
-        if(HDF5_OBJECTDIR_VERSION != *p++)
-            HGOTO_ERROR(H5E_FILE, H5E_BADVALUE, NULL, "bad object directory version number")
-
-        /* Skip over reserved byte */
-        p++;
-
-        /* Shared header version number (hard-wired) */
-        if(HDF5_SHAREDHEADER_VERSION != *p++)
-            HGOTO_ERROR(H5E_FILE, H5E_BADVALUE, NULL, "bad shared-header format version number")
-
-        /* Size of file addresses */
-        sizeof_addr = *p++;
-        if(sizeof_addr != 2 && sizeof_addr != 4 &&
-                sizeof_addr != 8 && sizeof_addr != 16 && sizeof_addr != 32)
-            HGOTO_ERROR(H5E_FILE, H5E_BADVALUE, NULL, "bad byte number in an address")
-        if(H5P_set(c_plist, H5F_CRT_ADDR_BYTE_NUM_NAME, &sizeof_addr) < 0)
-            HGOTO_ERROR(H5E_PLIST, H5E_CANTSET, NULL, "unable to set byte number in an address")
-        shared->sizeof_addr = sizeof_addr;  /* Keep a local copy also */
-
-        /* Size of file sizes */
-        sizeof_size = *p++;
-        if(sizeof_size != 2 && sizeof_size != 4 &&
-                sizeof_size != 8 && sizeof_size != 16 && sizeof_size != 32)
-            HGOTO_ERROR(H5E_FILE, H5E_BADVALUE, NULL, "bad byte number for object size")
-        if(H5P_set(c_plist, H5F_CRT_OBJ_BYTE_NUM_NAME, &sizeof_size) < 0)
-            HGOTO_ERROR(H5E_PLIST, H5E_CANTSET, NULL, "unable to set byte number for object size")
-        shared->sizeof_size = sizeof_size;  /* Keep a local copy also */
-
-        /* Skip over reserved byte */
-        p++;
-
-        /* Various B-tree sizes */
-        UINT16DECODE(p, sym_leaf_k);
-        if(sym_leaf_k == 0)
-            HGOTO_ERROR(H5E_FILE, H5E_BADRANGE, NULL, "bad symbol table leaf node 1/2 rank")
-        if(H5P_set(c_plist, H5F_CRT_SYM_LEAF_NAME, &sym_leaf_k) < 0)
-            HGOTO_ERROR(H5E_PLIST, H5E_CANTSET, NULL, "unable to set rank for symbol table leaf nodes")
-        sblock->sym_leaf_k = sym_leaf_k;    /* Keep a local copy also */
-
-        /* Need 'get' call to set other array values */
-        if(H5P_get(c_plist, H5F_CRT_BTREE_RANK_NAME, btree_k) < 0)
-            HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, NULL, "unable to get rank for btree internal nodes")
-        UINT16DECODE(p, btree_k[H5B_SNODE_ID]);
-        if(btree_k[H5B_SNODE_ID] == 0)
-            HGOTO_ERROR(H5E_FILE, H5E_BADRANGE, NULL, "bad 1/2 rank for btree internal nodes")
-        /*
-         * Delay setting the value in the property list until we've checked
-         * for the indexed storage B-tree internal 'K' value later.
-         */
-
-        /* File status flags (not really used yet) */
-        UINT32DECODE(p, status_flags);
-        HDassert(status_flags <= 255);
-        sblock->status_flags = (uint8_t)status_flags;
-        if(sblock->status_flags & ~H5F_SUPER_ALL_FLAGS)
-            HGOTO_ERROR(H5E_FILE, H5E_BADVALUE, NULL, "bad flag value for superblock")
-
-        /*
-         * If the superblock version # is greater than 0, read in the indexed
-         * storage B-tree internal 'K' value
-         */
-        if(super_vers > HDF5_SUPERBLOCK_VERSION_DEF) {
-            UINT16DECODE(p, btree_k[H5B_CHUNK_ID]);
-            /* Reserved bytes are present only in version 1 */
-            if(super_vers == HDF5_SUPERBLOCK_VERSION_1)
-                p += 2;   /* reserved */
-        } /* end if */
-        else
-            btree_k[H5B_CHUNK_ID] = HDF5_BTREE_CHUNK_IK_DEF;
+        /* Make certain we can read the variabled-sized portion of the superblock */
+        if(H5F__set_eoa(udata->f, H5FD_MEM_SUPER, (haddr_t)(H5F_SUPERBLOCK_FIXED_SIZE + variable_size)) < 0)
+            HGOTO_ERROR(H5E_FILE, H5E_CANTINIT, NULL, "set end of space allocation request failed")
+    } /* end if */
+    else {
+        /* Check for older version of superblock format */
+        if(super_vers < HDF5_SUPERBLOCK_VERSION_2) {
+            uint32_t    status_flags;	    /* File status flags	   */
+            unsigned    sym_leaf_k;         /* Symbol table leaf node's 'K' value */
+            unsigned    snode_btree_k;      /* B-tree symbol table internal node 'K' value */
+            unsigned    chunk_btree_k;      /* B-tree chunk internal node 'K' value */
+
+            /* Freespace version (hard-wired) */
+            if(HDF5_FREESPACE_VERSION != *image++)
+                HGOTO_ERROR(H5E_FILE, H5E_BADVALUE, NULL, "bad free space version number")
+
+            /* Root group version number (hard-wired) */
+            if(HDF5_OBJECTDIR_VERSION != *image++)
+                HGOTO_ERROR(H5E_FILE, H5E_BADVALUE, NULL, "bad object directory version number")
+
+            /* Skip over reserved byte */
+            image++;
+
+            /* Shared header version number (hard-wired) */
+            if(HDF5_SHAREDHEADER_VERSION != *image++)
+                HGOTO_ERROR(H5E_FILE, H5E_BADVALUE, NULL, "bad shared-header format version number")
+
+            /* Size of file addresses */
+            sizeof_addr = *image++;
+            if(sizeof_addr != 2 && sizeof_addr != 4 &&
+                    sizeof_addr != 8 && sizeof_addr != 16 && sizeof_addr != 32)
+                HGOTO_ERROR(H5E_FILE, H5E_BADVALUE, NULL, "bad byte number in an address")
+            sblock->sizeof_addr = sizeof_addr;
+            udata->f->shared->sizeof_addr = sizeof_addr;  /* Keep a local copy also */
+
+            /* Size of file sizes */
+            sizeof_size = *image++;
+            if(sizeof_size != 2 && sizeof_size != 4 &&
+                    sizeof_size != 8 && sizeof_size != 16 && sizeof_size != 32)
+                HGOTO_ERROR(H5E_FILE, H5E_BADVALUE, NULL, "bad byte number for object size")
+            sblock->sizeof_size = sizeof_size;
+            udata->f->shared->sizeof_size = sizeof_size;  /* Keep a local copy also */
+
+            /* Skip over reserved byte */
+            image++;
+
+            /* Various B-tree sizes */
+            UINT16DECODE(image, sym_leaf_k);
+            if(sym_leaf_k == 0)
+                HGOTO_ERROR(H5E_FILE, H5E_BADRANGE, NULL, "bad symbol table leaf node 1/2 rank")
+            udata->sym_leaf_k = sym_leaf_k;    /* Keep a local copy also */
+
+            /* Need 'get' call to set other array values */
+            UINT16DECODE(image, snode_btree_k);
+            if(snode_btree_k == 0)
+                HGOTO_ERROR(H5E_FILE, H5E_BADRANGE, NULL, "bad 1/2 rank for btree internal nodes")
+            udata->btree_k[H5B_SNODE_ID] = snode_btree_k;
 
-        /* Set the B-tree internal node values, etc */
-        if(H5P_set(c_plist, H5F_CRT_BTREE_RANK_NAME, btree_k) < 0)
-            HGOTO_ERROR(H5E_PLIST, H5E_CANTSET, NULL, "unable to set rank for btree internal nodes")
-        HDmemcpy(sblock->btree_k, btree_k, sizeof(unsigned) * (size_t)H5B_NUM_BTREE_ID);    /* Keep a local copy also */
+            /*
+             * Delay setting the value in the property list until we've checked
+             * for the indexed storage B-tree internal 'K' value later.
+             */
 
-        /* Remainder of "variable-sized" portion of superblock */
-        H5F_addr_decode(f, (const uint8_t **)&p, &sblock->base_addr/*out*/);
-        H5F_addr_decode(f, (const uint8_t **)&p, &sblock->ext_addr/*out*/);
-        H5F_addr_decode(f, (const uint8_t **)&p, &stored_eof/*out*/);
-        H5F_addr_decode(f, (const uint8_t **)&p, &sblock->driver_addr/*out*/);
+            /* File status flags (not really used yet) */
+            UINT32DECODE(image, status_flags);
+            HDassert(status_flags <= 255);
+            sblock->status_flags = (uint8_t)status_flags;
+            if(sblock->status_flags & ~H5F_SUPER_ALL_FLAGS)
+                HGOTO_ERROR(H5E_FILE, H5E_BADVALUE, NULL, "bad flag value for superblock")
 
-        /* Allocate space for the root group symbol table entry */
-        HDassert(!sblock->root_ent);
-        if(NULL == (sblock->root_ent = (H5G_entry_t *)H5MM_calloc(sizeof(H5G_entry_t))))
-            HGOTO_ERROR(H5E_FILE, H5E_CANTALLOC, NULL, "can't allocate space for root group symbol table entry")
+            /*
+             * If the superblock version # is greater than 0, read in the indexed
+             * storage B-tree internal 'K' value
+             */
+            if(super_vers > HDF5_SUPERBLOCK_VERSION_DEF) {
+                UINT16DECODE(image, chunk_btree_k);
 
-        /* decode the root group symbol table entry */
-        if(H5G_ent_decode(f, (const uint8_t **)&p, sblock->root_ent) < 0)
-            HGOTO_ERROR(H5E_FILE, H5E_CANTDECODE, NULL, "can't decode root group symbol table entry")
+                /* Reserved bytes are present only in version 1 */
+                if(super_vers == HDF5_SUPERBLOCK_VERSION_1)
+                    image += 2;   /* reserved */
+            } /* end if */
+            else
+                chunk_btree_k = HDF5_BTREE_CHUNK_IK_DEF;
+            udata->btree_k[H5B_CHUNK_ID] = chunk_btree_k;
+
+            /* Remainder of "variable-sized" portion of superblock */
+            H5F_addr_decode(udata->f, (const uint8_t **)&image, &sblock->base_addr/*out*/);
+            H5F_addr_decode(udata->f, (const uint8_t **)&image, &sblock->ext_addr/*out*/);
+            H5F_addr_decode(udata->f, (const uint8_t **)&image, &udata->stored_eof/*out*/);
+            H5F_addr_decode(udata->f, (const uint8_t **)&image, &sblock->driver_addr/*out*/);
+
+            /* Allocate space for the root group symbol table entry */
+            HDassert(!sblock->root_ent);
+            if(NULL == (sblock->root_ent = (H5G_entry_t *)H5MM_calloc(sizeof(H5G_entry_t))))
+                HGOTO_ERROR(H5E_FILE, H5E_CANTALLOC, NULL, "can't allocate space for root group symbol table entry")
+
+            /* decode the root group symbol table entry */
+            if(H5G_ent_decode(udata->f, (const uint8_t **)&image, sblock->root_ent) < 0)
+                HGOTO_ERROR(H5E_FILE, H5E_CANTDECODE, NULL, "can't decode root group symbol table entry")
+
+            /* Set the root group address to the correct value */
+            sblock->root_addr = sblock->root_ent->header;
+
+            /* This step is for h5repart tool only. If user wants to change file driver
+             *  from family to sec2 while using h5repart, set the driver address to
+             *  undefined to let the library ignore the family driver information saved
+             *  in the superblock.
+             */
+            if(udata->ignore_drvrinfo && H5F_addr_defined(sblock->driver_addr)) {
+                /* Eliminate the driver info */
+                sblock->driver_addr = HADDR_UNDEF;
+                udata->drvrinfo_removed = TRUE;
+            } /* end if */
 
-        /* Set the root group address to the correct value */
-        sblock->root_addr = sblock->root_ent->header;
+            /* NOTE: Driver info block is decoded separately, later */
 
-        /*
-         * Check if superblock address is different from base address and
-         * adjust base address and "end of address" address if so.
-         */
-        if(!H5F_addr_eq(base_addr, sblock->base_addr)) {
-            /* Check if the superblock moved earlier in the file */
-            if(H5F_addr_lt(base_addr, sblock->base_addr))
-                stored_eof -= (sblock->base_addr - base_addr);
-            else
-                /* The superblock moved later in the file */
-                stored_eof += (base_addr - sblock->base_addr);
+        } /* end if */
+        else {
+            uint32_t computed_chksum;       /* Computed checksum  */
+            uint32_t read_chksum;           /* Checksum read from file  */
+
+            /* Size of file addresses */
+            sizeof_addr = *image++;
+            if(sizeof_addr != 2 && sizeof_addr != 4 &&
+                    sizeof_addr != 8 && sizeof_addr != 16 && sizeof_addr != 32)
+                HGOTO_ERROR(H5E_FILE, H5E_BADVALUE, NULL, "bad byte number in an address")
+            sblock->sizeof_addr = sizeof_addr;
+            udata->f->shared->sizeof_addr = sizeof_addr;  /* Keep a local copy also */
+
+            /* Size of file sizes */
+            sizeof_size = *image++;
+            if(sizeof_size != 2 && sizeof_size != 4 &&
+                    sizeof_size != 8 && sizeof_size != 16 && sizeof_size != 32)
+                HGOTO_ERROR(H5E_FILE, H5E_BADVALUE, NULL, "bad byte number for object size")
+            sblock->sizeof_size = sizeof_size;
+            udata->f->shared->sizeof_size = sizeof_size;  /* Keep a local copy also */
+
+            /* File status flags (not really used yet) */
+            sblock->status_flags = *image++;
+            if(sblock->status_flags & ~H5F_SUPER_ALL_FLAGS)
+                HGOTO_ERROR(H5E_FILE, H5E_BADVALUE, NULL, "bad flag value for superblock")
+
+            /* Base, superblock extension, end of file & root group object header addresses */
+            H5F_addr_decode(udata->f, (const uint8_t **)&image, &sblock->base_addr/*out*/);
+            H5F_addr_decode(udata->f, (const uint8_t **)&image, &sblock->ext_addr/*out*/);
+            H5F_addr_decode(udata->f, (const uint8_t **)&image, &udata->stored_eof/*out*/);
+            H5F_addr_decode(udata->f, (const uint8_t **)&image, &sblock->root_addr/*out*/);
+
+            /* Compute checksum for superblock */
+            computed_chksum = H5_checksum_metadata(_image, (size_t)(image - (const uint8_t *)_image), 0);
+
+            /* Decode checksum */
+            UINT32DECODE(image, read_chksum);
+
+            /* Verify correct checksum */
+            if(read_chksum != computed_chksum)
+                HGOTO_ERROR(H5E_FILE, H5E_CANTOPENFILE, NULL, "bad checksum on driver information block")
+
+            /* The Driver Information Block may not appear with the version
+             * 2 super block.  Thus we set the driver_addr field of the in 
+             * core representation of the super block HADDR_UNDEF to prevent 
+             * any attempt to load the Driver Information Block.
+             */
+            sblock->driver_addr = HADDR_UNDEF;
+        } /* end else */
+    } /* end else */
 
-            /* Adjust base address for offsets of the HDF5 data in the file */
-            sblock->base_addr = base_addr;
+    /* Sanity check */
+    HDassert((size_t)(image - (const uint8_t *)_image) <= len);
 
-            /* Set the base address for the file in the VFD now */
-            if(H5FD_set_base_addr(lf, sblock->base_addr) < 0)
-                HGOTO_ERROR(H5E_FILE, H5E_CANTSET, NULL, "failed to set base address for file driver")
+    /* Set return value */
+    ret_value = sblock;
 
-            /* Indicate that the superblock should be marked dirty */
-            *dirtied = TRUE;
-        } /* end if */
+done:
+    /* Release the [possibly partially initialized] superblock on error */
+    if(!ret_value && sblock)
+        if(H5F__super_free(sblock) < 0)
+            HDONE_ERROR(H5E_FILE, H5E_CANTFREE, NULL, "unable to destroy superblock data")
 
-        /* This step is for h5repart tool only. If user wants to change file driver
-         *  from family to sec2 while using h5repart, set the driver address to
-         *  undefined to let the library ignore the family driver information saved
-         *  in the superblock.
-         */
-        if(H5F_HAS_FEATURE(f, H5FD_FEAT_IGNORE_DRVRINFO)) {
-            /* Eliminate the driver info */
-            sblock->driver_addr = HADDR_UNDEF;
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5F__cache_superblock_deserialize() */
 
-            /* Indicate that the superblock should be marked dirty */
-            *dirtied = TRUE;
-        } /* end if */
+
+/*-------------------------------------------------------------------------
+ * Function:    H5F__cache_superblock_image_len
+ *
+ * Purpose:     Compute the size of the data structure on disk.
+ *
+ * Return:      Non-negative on success/Negative on failure
+ *
+ * Programmer:  Quincey Koziol
+ *              koziol@hdfgroup.org
+ *              July 19, 2013
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+H5F__cache_superblock_image_len(const void *_thing, size_t *image_len, hbool_t *compressed_ptr, size_t H5_ATTR_UNUSED *compressed_image_len_ptr)
+{
+    const H5F_super_t *sblock = (const H5F_super_t *)_thing;    /* Pointer to the object */
 
-        /* Decode the optional driver information block */
-        if(H5F_addr_defined(sblock->driver_addr)) {
-            uint8_t dbuf[H5F_MAX_DRVINFOBLOCK_SIZE];     /* Buffer for driver info block */
-            char drv_name[9];       /* Name of driver */
-            unsigned drv_vers;      /* Version of driver info block */
-            size_t drv_variable_size; /* Size of variable-length portion of driver info block, in bytes */
-
-            /* Read in fixed-sized portion of driver info block */
-            p = dbuf;
-            if(H5FD_set_eoa(lf, H5FD_MEM_SUPER, sblock->driver_addr + H5F_DRVINFOBLOCK_HDR_SIZE) < 0)
-                HGOTO_ERROR(H5E_FILE, H5E_CANTINIT, NULL, "set end of space allocation request failed")
-            if(H5FD_read(lf, dxpl, H5FD_MEM_SUPER, sblock->driver_addr, (size_t)H5F_DRVINFOBLOCK_HDR_SIZE, p) < 0)
-                HGOTO_ERROR(H5E_FILE, H5E_CANTOPENFILE, NULL, "unable to read driver information block")
-
-            /* Version number */
-            drv_vers = *p++;
-            if(drv_vers != HDF5_DRIVERINFO_VERSION_0)
-                HGOTO_ERROR(H5E_FILE, H5E_CANTOPENFILE, NULL, "bad driver information block version number")
-
-            p += 3; /* reserved bytes */
-
-            /* Driver info size */
-            UINT32DECODE(p, drv_variable_size);
-
-            /* Sanity check */
-            HDassert(H5F_DRVINFOBLOCK_HDR_SIZE + drv_variable_size <= sizeof(dbuf));
-
-            /* Driver name and/or version */
-            HDstrncpy(drv_name, (const char *)p, (size_t)8);
-            drv_name[8] = '\0';
-            p += 8; /* advance past name/version */
-
-            /* Read in variable-sized portion of driver info block */
-            if(H5FD_set_eoa(lf, H5FD_MEM_SUPER, sblock->driver_addr + H5F_DRVINFOBLOCK_HDR_SIZE + drv_variable_size) < 0)
-                HGOTO_ERROR(H5E_FILE, H5E_CANTINIT, NULL, "set end of space allocation request failed")
-            if(H5FD_read(lf, dxpl, H5FD_MEM_SUPER, sblock->driver_addr + H5F_DRVINFOBLOCK_HDR_SIZE, drv_variable_size, p) < 0)
-                HGOTO_ERROR(H5E_FILE, H5E_CANTOPENFILE, NULL, "unable to read file driver information")
-
-            /* Decode driver information */
-            if(H5FD_sb_load(lf, drv_name, p) < 0)
-                HGOTO_ERROR(H5E_FILE, H5E_CANTOPENFILE, NULL, "unable to decode driver information")
-        } /* end if */
-    } /* end if */
-    else {
-        uint32_t computed_chksum;       /* Computed checksum  */
-        uint32_t read_chksum;           /* Checksum read from file  */
-
-        /* Size of file addresses */
-        sizeof_addr = *p++;
-        if(sizeof_addr != 2 && sizeof_addr != 4 &&
-                sizeof_addr != 8 && sizeof_addr != 16 && sizeof_addr != 32)
-            HGOTO_ERROR(H5E_FILE, H5E_BADVALUE, NULL, "bad byte number in an address")
-        if(H5P_set(c_plist, H5F_CRT_ADDR_BYTE_NUM_NAME, &sizeof_addr) < 0)
-            HGOTO_ERROR(H5E_PLIST, H5E_CANTSET, NULL, "unable to set byte number in an address")
-        shared->sizeof_addr = sizeof_addr;  /* Keep a local copy also */
-
-        /* Size of file sizes */
-        sizeof_size = *p++;
-        if(sizeof_size != 2 && sizeof_size != 4 &&
-                sizeof_size != 8 && sizeof_size != 16 && sizeof_size != 32)
-            HGOTO_ERROR(H5E_FILE, H5E_BADVALUE, NULL, "bad byte number for object size")
-        if(H5P_set(c_plist, H5F_CRT_OBJ_BYTE_NUM_NAME, &sizeof_size) < 0)
-            HGOTO_ERROR(H5E_PLIST, H5E_CANTSET, NULL, "unable to set byte number for object size")
-        shared->sizeof_size = sizeof_size;  /* Keep a local copy also */
-
-        /* File status flags (not really used yet) */
-        sblock->status_flags = *p++;
-        if(sblock->status_flags & ~H5F_SUPER_ALL_FLAGS)
-            HGOTO_ERROR(H5E_FILE, H5E_BADVALUE, NULL, "bad flag value for superblock")
-
-        /* Base, superblock extension, end of file & root group object header addresses */
-        H5F_addr_decode(f, (const uint8_t **)&p, &sblock->base_addr/*out*/);
-        H5F_addr_decode(f, (const uint8_t **)&p, &sblock->ext_addr/*out*/);
-        H5F_addr_decode(f, (const uint8_t **)&p, &stored_eof/*out*/);
-        H5F_addr_decode(f, (const uint8_t **)&p, &sblock->root_addr/*out*/);
-
-        /* Compute checksum for superblock */
-        computed_chksum = H5_checksum_metadata(sbuf, (size_t)(p - sbuf), 0);
-
-        /* Decode checksum */
-        UINT32DECODE(p, read_chksum);
-
-        /* Verify correct checksum */
-        if(read_chksum != computed_chksum)
-            HGOTO_ERROR(H5E_FILE, H5E_CANTOPENFILE, NULL, "bad checksum on driver information block")
+    FUNC_ENTER_STATIC_NOERR
 
-        /*
-         * Check if superblock address is different from base address and
-         * adjust base address and "end of address" address if so.
-         */
-        if(!H5F_addr_eq(base_addr, sblock->base_addr)) {
-            /* Check if the superblock moved earlier in the file */
-            if(H5F_addr_lt(base_addr, sblock->base_addr))
-                stored_eof -= (sblock->base_addr - base_addr);
-            else
-                /* The superblock moved later in the file */
-                stored_eof += (base_addr - sblock->base_addr);
+    /* Check arguments */
+    HDassert(sblock);
+    HDassert(sblock->cache_info.magic == H5C__H5C_CACHE_ENTRY_T_MAGIC);
+    HDassert(sblock->cache_info.type == H5AC_SUPERBLOCK);
+    HDassert(image_len);
+    HDassert(compressed_ptr);
 
-            /* Adjust base address for offsets of the HDF5 data in the file */
-            sblock->base_addr = base_addr;
+    /* Set the image length size */
+    *image_len = (size_t)H5F_SUPERBLOCK_SIZE(sblock);
 
-            /* Set the base address for the file in the VFD now */
-            if(H5FD_set_base_addr(lf, sblock->base_addr) < 0)
-                HGOTO_ERROR(H5E_FILE, H5E_CANTSET, NULL, "failed to set base address for file driver")
+    /* Set *compressed_ptr to FALSE unconditionally */
+    *compressed_ptr;
 
-            /* Indicate that the superblock should be marked dirty */
-            *dirtied = TRUE;
-        } /* end if */
+    FUNC_LEAVE_NOAPI(SUCCEED)
+} /* end H5F__cache_superblock_image_len() */
 
-        /* Get the B-tree internal node values, etc */
-        if(H5P_get(c_plist, H5F_CRT_BTREE_RANK_NAME, sblock->btree_k) < 0)
-            HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, NULL, "unable to get rank for btree internal nodes")
-        if(H5P_get(c_plist, H5F_CRT_SYM_LEAF_NAME, &sblock->sym_leaf_k) < 0)
-            HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, NULL, "unable to get rank for btree internal nodes")
-    } /* end else */
+
+/*-------------------------------------------------------------------------
+ * Function:    H5FS__cache_hdf_pre_serialize
+ *
+ * Purpose:	The current use of this function is a cludge to repair an 
+ *		oversight in the conversion of the superblock code to use the 
+ *		version 3 cache.  
+ *
+ *		In the V2 metadata cache callbacks, the superblock dirver info 
+ *     		message was updated in the flush routine.  Note that this 
+ *		operation only applies to version 2 or later superblocks.
+ *
+ *     		Somehow, this functionality was lost in the conversion to use 
+ *     		the V3 cache, causing failures with the multi file driver 
+ *     		(and possibly the family file driver as well).
+ *
+ *     		Performing this operation is impossible in the current 
+ *		serialize routine, as the dxpl_id is not available.  While 
+ *		I am pretty sure that this is not the correct place for this 
+ *		functionality, as I can see it causing problems with both 
+ *		journaling and possibly parallel HDF5 as well, I am placing 
+ *		code for the necessary update in the pre_serialize call for 
+ *		now for testing purposes.  We will almost certainly want to 
+ *		change this.
+ *
+ * Return:      Success:        SUCCEED
+ *              Failure:        FAIL
+ *
+ * Programmer:  John Mainzer
+ *              10/82/14
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+H5F__cache_superblock_pre_serialize(const H5F_t *f, hid_t dxpl_id, 
+    void *_thing, haddr_t H5_ATTR_UNUSED addr, size_t H5_ATTR_UNUSED len, 
+    size_t H5_ATTR_UNUSED compressed_len, haddr_t H5_ATTR_UNUSED *new_addr, 
+    size_t H5_ATTR_UNUSED *new_len, size_t H5_ATTR_UNUSED *new_compressed_len, 
+    unsigned H5_ATTR_UNUSED *flags)
+{
+    H5F_super_t *sblock = (H5F_super_t *)_thing; /* Pointer to the super block */
+    herr_t ret_value = SUCCEED; /* Return value */
 
-    /*
-     * The user-defined data is the area of the file before the base
-     * address.
-     */
-    if(H5P_set(c_plist, H5F_CRT_USER_BLOCK_NAME, &sblock->base_addr) < 0)
-        HGOTO_ERROR(H5E_PLIST, H5E_CANTSET, NULL, "unable to set userblock size")
+    FUNC_ENTER_NOAPI_NOINIT
 
-    /*
-     * Make sure that the data is not truncated. One case where this is
-     * possible is if the first file of a family of files was opened
-     * individually.
-     */
-    if(HADDR_UNDEF == (eof = H5FD_get_eof(lf, H5FD_MEM_DEFAULT)))
-        HGOTO_ERROR(H5E_FILE, H5E_CANTGET, NULL, "unable to determine file size")
-
-    /* (Account for the stored EOF being absolute offset -QAK) */
-    if((eof + sblock->base_addr) < stored_eof)
-        HGOTO_ERROR(H5E_FILE, H5E_TRUNCATED, NULL,
-                    "truncated file: eof = %llu, sblock->base_addr = %llu, stored_eof = %llu",
-                    (unsigned long long)eof, (unsigned long long)sblock->base_addr, (unsigned long long)stored_eof)
-
-    /*
-     * Tell the file driver how much address space has already been
-     * allocated so that it knows how to allocate additional memory.
-     */
-    /* (Account for the stored EOA being absolute offset -NAF) */
-    if(H5FD_set_eoa(lf, H5FD_MEM_SUPER, stored_eof - sblock->base_addr) < 0)
-        HGOTO_ERROR(H5E_FILE, H5E_CANTOPENFILE, NULL, "unable to set end-of-address marker for file")
-
-    /* Read the file's superblock extension, if there is one. */
-    if(H5F_addr_defined(sblock->ext_addr)) {
-        H5O_loc_t ext_loc;      /* "Object location" for superblock extension */
-        H5O_btreek_t btreek;    /* v1 B-tree 'K' value message from superblock extension */
-        H5O_drvinfo_t drvinfo;  /* Driver info message from superblock extension */
-	size_t u; 		/* Local index variable */
-        htri_t status;          /* Status for message existing */
-
-        /* Sanity check - superblock extension should only be defined for
-         *      superblock version >= 2.
+    /* Sanity check */
+    HDassert(f);
+    HDassert(sblock);
+    HDassert(sblock->cache_info.magic == H5C__H5C_CACHE_ENTRY_T_MAGIC);
+    HDassert(sblock->cache_info.type == H5AC_SUPERBLOCK);
+    HDassert(flags);
+
+    if(sblock->super_vers >= HDF5_SUPERBLOCK_VERSION_2) {
+        /* WARNING: This code almost certainly doesn't belong here.  Must
+         *          discuss with Quincey where to put it.  Note issues
+         *          for journaling and possibly parallel.
+         *
+         *                                            -- JRM
          */
-        HDassert(super_vers >= HDF5_SUPERBLOCK_VERSION_2);
-
-        /* Check for superblock extension being located "outside" the stored
-         *      'eoa' value, which can occur with the split/multi VFD.
+        /* Update the driver information message in the superblock extension
+         * if appropriate.
          */
-        if(H5F_addr_gt(sblock->ext_addr, stored_eof)) {
-            /* Set the 'eoa' for the object header memory type large enough
-             *  to give some room for a reasonably sized superblock extension.
-             *  (This is _rather_ a kludge -QAK)
-             */
-            if(H5FD_set_eoa(lf, H5FD_MEM_OHDR, (haddr_t)(sblock->ext_addr + 1024)) < 0)
-                HGOTO_ERROR(H5E_FILE, H5E_CANTOPENFILE, NULL, "unable to set end-of-address marker for file")
-        } /* end if */
+        if(H5F_addr_defined(sblock->ext_addr)) {
+            size_t     driver_size;    /* Size of driver info block (bytes)*/
+            H5O_loc_t  ext_loc;        /* "Object location" for superblock extension */
 
-        /* Open the superblock extension */
-	if(H5F_super_ext_open(f, sblock->ext_addr, &ext_loc) < 0)
-            HGOTO_ERROR(H5E_FILE, H5E_CANTOPENOBJ, NULL, "unable to open file's superblock extension")
+            HDassert(sblock->super_vers >= HDF5_SUPERBLOCK_VERSION_2);
+
+            /* Open the superblock extension's object header */
+            if(H5F_super_ext_open((H5F_t *)f, sblock->ext_addr, &ext_loc) < 0)
+                HGOTO_ERROR(H5E_FILE, H5E_CANTOPENOBJ, FAIL, "unable to open file's superblock extension")
 
-        /* Check for the extension having a 'driver info' message */
-        if((status = H5O_msg_exists(&ext_loc, H5O_DRVINFO_ID, dxpl_id)) < 0)
-            HGOTO_ERROR(H5E_FILE, H5E_CANTGET, NULL, "unable to read object header")
-        if(status) {
             /* Check for ignoring the driver info for this file */
-            if(H5F_HAS_FEATURE(f, H5FD_FEAT_IGNORE_DRVRINFO)) {
-                /* Indicate that the superblock should be marked dirty */
-                *dirtied = TRUE;
-            } /* end if */
-            else {
-                /* Retrieve the 'driver info' structure */
-                if(NULL == H5O_msg_read(&ext_loc, H5O_DRVINFO_ID, &drvinfo, dxpl_id))
-                    HGOTO_ERROR(H5E_FILE, H5E_CANTGET, NULL, "driver info message not present")
-
-                /* Decode driver information */
-                if(H5FD_sb_load(lf, drvinfo.name, drvinfo.buf) < 0)
-                    HGOTO_ERROR(H5E_FILE, H5E_CANTOPENFILE, NULL, "unable to decode driver information")
-
-                /* Reset driver info message */
-                H5O_msg_reset(H5O_DRVINFO_ID, &drvinfo);
-            } /* end else */
-        } /* end if */
+            if(!H5F_HAS_FEATURE(f, H5FD_FEAT_IGNORE_DRVRINFO)) {
+                /* Check for driver info message */
+                H5_CHECKED_ASSIGN(driver_size, size_t, H5FD_sb_size(f->shared->lf), hsize_t);
+                if(driver_size > 0) {
+                    H5O_drvinfo_t drvinfo;      /* Driver info */
+                    uint8_t dbuf[H5F_MAX_DRVINFOBLOCK_SIZE];  /* Driver info block encoding buffer */
 
-        /* Read in the shared OH message information if there is any */
-        if(H5SM_get_info(&ext_loc, c_plist, dxpl_id) < 0)
-            HGOTO_ERROR(H5E_FILE, H5E_CANTOPENFILE, NULL, "unable to read SOHM table information")
-
-        /* Check for the extension having a 'v1 B-tree "K"' message */
-        if((status = H5O_msg_exists(&ext_loc, H5O_BTREEK_ID, dxpl_id)) < 0)
-            HGOTO_ERROR(H5E_FILE, H5E_CANTGET, NULL, "unable to read object header")
-        if(status) {
-            /* Retrieve the 'v1 B-tree "K"' structure */
-            if(NULL == H5O_msg_read(&ext_loc, H5O_BTREEK_ID, &btreek, dxpl_id))
-                HGOTO_ERROR(H5E_FILE, H5E_CANTGET, NULL, "v1 B-tree 'K' info message not present")
-
-            /* Set non-default v1 B-tree 'K' value info from file */
-            sblock->btree_k[H5B_CHUNK_ID] = btreek.btree_k[H5B_CHUNK_ID];
-            sblock->btree_k[H5B_SNODE_ID] = btreek.btree_k[H5B_SNODE_ID];
-            sblock->sym_leaf_k = btreek.sym_leaf_k;
-
-            /* Set non-default v1 B-tree 'K' values in the property list */
-            if(H5P_set(c_plist, H5F_CRT_BTREE_RANK_NAME, btreek.btree_k) < 0)
-                HGOTO_ERROR(H5E_PLIST, H5E_CANTSET, NULL, "unable to set rank for btree internal nodes")
-            if(H5P_set(c_plist, H5F_CRT_SYM_LEAF_NAME, &btreek.sym_leaf_k) < 0)
-                HGOTO_ERROR(H5E_PLIST, H5E_CANTSET, NULL, "unable to set rank for symbol table leaf nodes")
-        } /* end if */
+                    /* Sanity check */
+                    HDassert(driver_size <= H5F_MAX_DRVINFOBLOCK_SIZE);
 
-        /* Check for the extension having a 'free-space manager info' message */
-        if((status = H5O_msg_exists(&ext_loc, H5O_FSINFO_ID, dxpl_id)) < 0)
-            HGOTO_ERROR(H5E_FILE, H5E_CANTGET, NULL, "unable to check object header")
-        if(status) {
-            H5O_fsinfo_t fsinfo;    /* Free-space manager info message from superblock extension */
-
-            /* Retrieve the 'free-space manager info' structure */
-	    if(NULL == H5O_msg_read(&ext_loc, H5O_FSINFO_ID, &fsinfo, dxpl_id))
-                HGOTO_ERROR(H5E_OHDR, H5E_CANTGET, NULL, "unable to get free-space manager info message")
-
-	    if(shared->fs_strategy != fsinfo.strategy) {
-		shared->fs_strategy = fsinfo.strategy;
-
-		/* Set non-default strategy in the property list */
-		if(H5P_set(c_plist, H5F_CRT_FILE_SPACE_STRATEGY_NAME, &fsinfo.strategy) < 0)
-		    HGOTO_ERROR(H5E_FILE, H5E_CANTSET, NULL, "unable to set file space strategy")
-	    } /* end if */
-	    if(shared->fs_threshold != fsinfo.threshold) {
-		shared->fs_threshold = fsinfo.threshold;
-
-		/* Set non-default threshold in the property list */
-		if(H5P_set(c_plist, H5F_CRT_FREE_SPACE_THRESHOLD_NAME, &fsinfo.threshold) < 0)
-		    HGOTO_ERROR(H5E_FILE, H5E_CANTSET, NULL, "unable to set file space strategy")
-	    } /* end if */
-
-	    /* set free-space manager addresses */
-	    shared->fs_addr[0] = HADDR_UNDEF;
-	    for(u = 1; u < NELMTS(f->shared->fs_addr); u++)
-		shared->fs_addr[u] = fsinfo.fs_addr[u-1];
-        } /* end if */
+                    /* Encode driver-specific data */
+                    if(H5FD_sb_encode(f->shared->lf, drvinfo.name, dbuf) < 0)
+                        HGOTO_ERROR(H5E_FILE, H5E_CANTINIT, FAIL, "unable to encode driver information")
 
-        /* Close superblock extension */
-        if(H5F_super_ext_close(f, &ext_loc, dxpl_id, FALSE) < 0)
-	    HGOTO_ERROR(H5E_FILE, H5E_CANTRELEASE, NULL, "unable to close file's superblock extension")
-    } /* end if */
+                    /* Write driver info information to the superblock extension */
+                    drvinfo.len = driver_size;
+                    drvinfo.buf = dbuf;
+                    if(H5O_msg_write(&ext_loc, H5O_DRVINFO_ID, H5O_MSG_FLAG_DONTSHARE, H5O_UPDATE_TIME, &drvinfo, dxpl_id) < 0)
+                        HGOTO_ERROR(H5E_FILE, H5E_WRITEERROR, FAIL, "unable to update driver info header message")
+                } /* end if */
+            } /* end if */
 
-    /* Set return value */
-    ret_value = sblock;
+            /* Close the superblock extension object header */
+            if(H5F_super_ext_close((H5F_t *)f, &ext_loc, dxpl_id, FALSE) < 0)
+                HGOTO_ERROR(H5E_FILE, H5E_CANTCLOSEOBJ, FAIL, "unable to close file's superblock extension")
+        } /* end if */
+    } /* end if */
 
 done:
-    /* Release the [possibly partially initialized] superblock on errors */
-    if(!ret_value && sblock)
-        if(H5F__super_free(sblock) < 0)
-            HDONE_ERROR(H5E_FILE, H5E_CANTFREE, NULL, "unable to destroy superblock data")
-
     FUNC_LEAVE_NOAPI(ret_value)
-} /* end H5F_sblock_load() */
+} /* end H5FS_cache_superblock_pre_serialize() */
 
 
 /*-------------------------------------------------------------------------
- * Function:    H5F_sblock_flush
+ * Function:	H5F__cache_superblock_serialize
  *
- * Purpose:     Flushes the superblock.
+ * Purpose:	Flushes a dirty object to disk.
  *
- * Return:      Success:        SUCCEED
- *              Failure:        NULL
+ * Return:	Non-negative on success/Negative on failure
  *
- * Programmer:  Mike McGreevy
- *              mamcgree@hdfgroup.org
- *              April 8, 2009
+ * Programmer:	Quincey Koziol
+ *		koziol@hdfgroup.org
+ *		July 19 2013
  *
  *-------------------------------------------------------------------------
  */
 static herr_t
-H5F_sblock_flush(H5F_t *f, hid_t dxpl_id, hbool_t destroy, haddr_t H5_ATTR_UNUSED addr,
-    H5F_super_t *sblock)
+H5F__cache_superblock_serialize(const H5F_t *f, void *_image, size_t H5_ATTR_UNUSED len,
+    void *_thing)
 {
-    herr_t          ret_value = SUCCEED;
+    H5F_super_t *sblock = (H5F_super_t *)_thing;      /* Pointer to the object */
+    uint8_t *image = (uint8_t *)_image;         /* Pointer into raw data buffer */
+    haddr_t rel_eof;            /* Relative EOF for file */
+    herr_t ret_value = SUCCEED; /* Return value */
 
-    FUNC_ENTER_NOAPI_NOINIT
+    FUNC_ENTER_STATIC
 
-    /* check arguments */
+    /* Sanity check */
     HDassert(f);
-    HDassert(H5F_addr_eq(addr, 0));
+    HDassert(image);
     HDassert(sblock);
-    
+
     /* Assert that the superblock is marked as being flushed last (and 
        collectively in parallel) */
     /* (We'll rely on the cache to make sure it actually *is* flushed
@@ -656,301 +619,403 @@ H5F_sblock_flush(H5F_t *f, hid_t dxpl_id, hbool_t destroy, haddr_t H5_ATTR_UNUSE
     HDassert(sblock->cache_info.flush_me_collectively);
 #endif
 
-    if(sblock->cache_info.is_dirty) {
-        H5P_genplist_t *dxpl;               /* DXPL object */
-        uint8_t         buf[H5F_MAX_SUPERBLOCK_SIZE + H5F_MAX_DRVINFOBLOCK_SIZE];  /* Superblock & driver info blockencoding buffer */
-        uint8_t        *p;                  /* Ptr into encoding buffer */
-        haddr_t         rel_eof;            /* Relative EOF for file */
-        size_t          superblock_size;    /* Size of superblock, in bytes */
-        size_t          driver_size;        /* Size of driver info block (bytes)*/
+    /* Encode the common portion of the file superblock for all versions */
+    HDmemcpy(image, H5F_SIGNATURE, (size_t)H5F_SIGNATURE_LEN);
+    image += H5F_SIGNATURE_LEN;
+    *image++ = (uint8_t)sblock->super_vers;
 
-        /* Encode the common portion of the file superblock for all versions */
-        p = buf;
-        HDmemcpy(p, H5F_SIGNATURE, (size_t)H5F_SIGNATURE_LEN);
-        p += H5F_SIGNATURE_LEN;
-        *p++ = (uint8_t)sblock->super_vers;
+    /* Check for older version of superblock format */
+    if(sblock->super_vers < HDF5_SUPERBLOCK_VERSION_2) {
+        *image++ = (uint8_t)HDF5_FREESPACE_VERSION;     /* (hard-wired) */
+        *image++ = (uint8_t)HDF5_OBJECTDIR_VERSION;     /* (hard-wired) */
+        *image++ = 0;   /* reserved*/
 
-        /* Check for older version of superblock format */
-        if(sblock->super_vers < HDF5_SUPERBLOCK_VERSION_2) {
-            *p++ = (uint8_t)HDF5_FREESPACE_VERSION;     /* (hard-wired) */
-            *p++ = (uint8_t)HDF5_OBJECTDIR_VERSION;     /* (hard-wired) */
-            *p++ = 0;   /* reserved*/
+        *image++ = (uint8_t)HDF5_SHAREDHEADER_VERSION;  /* (hard-wired) */
+        *image++ = sblock->sizeof_addr;
+        *image++ = sblock->sizeof_size;
+        *image++ = 0;   /* reserved */
 
-            *p++ = (uint8_t)HDF5_SHAREDHEADER_VERSION;  /* (hard-wired) */
-            *p++ = (uint8_t)H5F_SIZEOF_ADDR(f);
-            *p++ = (uint8_t)H5F_SIZEOF_SIZE(f);
-            *p++ = 0;   /* reserved */
+        UINT16ENCODE(image, sblock->sym_leaf_k);
+        UINT16ENCODE(image, sblock->btree_k[H5B_SNODE_ID]);
+        UINT32ENCODE(image, (uint32_t)sblock->status_flags);
 
-            UINT16ENCODE(p, sblock->sym_leaf_k);
-            UINT16ENCODE(p, sblock->btree_k[H5B_SNODE_ID]);
-            UINT32ENCODE(p, (uint32_t)sblock->status_flags);
+        /*
+         * Versions of the superblock >0 have the indexed storage B-tree
+         * internal 'K' value stored
+         */
+        if(sblock->super_vers > HDF5_SUPERBLOCK_VERSION_DEF) {
+            UINT16ENCODE(image, sblock->btree_k[H5B_CHUNK_ID]);
+            *image++ = 0;   /*reserved */
+            *image++ = 0;   /*reserved */
+        } /* end if */
 
-            /*
-             * Versions of the superblock >0 have the indexed storage B-tree
-             * internal 'K' value stored
-             */
-            if(sblock->super_vers > HDF5_SUPERBLOCK_VERSION_DEF) {
-                UINT16ENCODE(p, sblock->btree_k[H5B_CHUNK_ID]);
-                *p++ = 0;   /*reserved */
-                *p++ = 0;   /*reserved */
-            } /* end if */
+        /* Encode the base address */
+        H5F_addr_encode(f, &image, sblock->base_addr);
 
-            /* Encode the base address */
-            H5F_addr_encode(f, &p, sblock->base_addr);
-
-            /* Encode the address of global free-space index */
-            H5F_addr_encode(f, &p, sblock->ext_addr);
-
-            /* Encode the end-of-file address. Note that at this point in time,
-             * the EOF value itself may not be reflective of the file's size, as
-             * we will eventually truncate the file to match the EOA value. As
-             * such, use the EOA value in its place, knowing that the current EOF
-             * value will ultimately match it. */
-            if ((rel_eof = H5FD_get_eoa(f->shared->lf, H5FD_MEM_SUPER)) == HADDR_UNDEF)
-                HGOTO_ERROR(H5E_RESOURCE, H5E_CANTGET, FAIL, "driver get_eoa request failed")
-            H5F_addr_encode(f, &p, (rel_eof + sblock->base_addr));
-
-            /* Encode the driver informaton block address */
-            H5F_addr_encode(f, &p, sblock->driver_addr);
-
-            /* Encode the root group object entry, including the cached stab info */
-            if(H5G_ent_encode(f, &p, sblock->root_ent) < 0)
-                HGOTO_ERROR(H5E_FILE, H5E_CANTENCODE, FAIL, "can't encode root group symbol table entry")
-
-            /* Encode the driver information block. */
-            H5_CHECKED_ASSIGN(driver_size, size_t, H5FD_sb_size(f->shared->lf), hsize_t);
-
-            /* Checking whether driver block address is defined here is to handle backward
-             * compatibility.  If the file was created with v1.6 library or earlier and no
-             * driver info block was written in the superblock, we don't write it either even
-             * though there's some driver info.  Otherwise, the driver block extended will
-             * overwrite the (meta)data right after the superblock. This situation happens to
-             * the family driver particularly.  SLU - 2009/3/24
-             */
-            if(driver_size > 0 && H5F_addr_defined(sblock->driver_addr)) {
-                char driver_name[9];    /* Name of driver, for driver info block */
-                uint8_t *dbuf = p;      /* Pointer to beginning of driver info */
+        /* Encode the address of global free-space index */
+        H5F_addr_encode(f, &image, sblock->ext_addr);
 
-                /* Encode the driver information block */
-                *p++ = HDF5_DRIVERINFO_VERSION_0; /* Version */
-                *p++ = 0; /* reserved */
-                *p++ = 0; /* reserved */
-                *p++ = 0; /* reserved */
+        /* Encode the end-of-file address. Note that at this point in time,
+         * the EOF value itself may not be reflective of the file's size, as
+         * we will eventually truncate the file to match the EOA value. As
+         * such, use the EOA value in its place, knowing that the current EOF
+         * value will ultimately match it. */
+        if ((rel_eof = H5FD_get_eoa(f->shared->lf, H5FD_MEM_SUPER)) == HADDR_UNDEF)
+            HGOTO_ERROR(H5E_RESOURCE, H5E_CANTGET, FAIL, "driver get_eoa request failed")
+        H5F_addr_encode(f, &image, (rel_eof + sblock->base_addr));
 
-                /* Driver info size, excluding header */
-                UINT32ENCODE(p, driver_size);
+        /* Encode the driver informaton block address */
+        H5F_addr_encode(f, &image, sblock->driver_addr);
 
-                /* Encode driver-specific data */
-                if(H5FD_sb_encode(f->shared->lf, driver_name, dbuf + H5F_DRVINFOBLOCK_HDR_SIZE) < 0)
-                    HGOTO_ERROR(H5E_FILE, H5E_CANTINIT, FAIL, "unable to encode driver information")
+        /* Encode the root group object entry, including the cached stab info */
+        if(H5G_ent_encode(f, &image, sblock->root_ent) < 0)
+            HGOTO_ERROR(H5E_FILE, H5E_CANTENCODE, FAIL, "can't encode root group symbol table entry")
 
-                /* Store driver name (set in 'H5FD_sb_encode' call above) */
-                HDmemcpy(p, driver_name, (size_t)8);
+        /* NOTE: Driver info block is handled separately */
 
-                /* Advance buffer pointer past name & variable-sized portion of driver info */
-                /* (for later use in computing the superblock size) */
-                p += 8 + driver_size;
-            } /* end if */
-        } /* end if */
-        else {
-            uint32_t        chksum;                 /* Checksum temporary variable      */
-            H5O_loc_t       *root_oloc;             /* Pointer to root group's object location */
+    } /* end if */
+    else { /* sblock->super_vers >= HDF5_SUPERBLOCK_VERSION_2 */
+        uint32_t        chksum;                 /* Checksum temporary variable      */
+        H5O_loc_t       *root_oloc;             /* Pointer to root group's object location */
 
-            /* Size of file addresses & offsets, and status flags */
-            *p++ = (uint8_t)H5F_SIZEOF_ADDR(f);
-            *p++ = (uint8_t)H5F_SIZEOF_SIZE(f);
-            *p++ = sblock->status_flags;
+        /* Size of file addresses & offsets, and status flags */
+        *image++ = sblock->sizeof_addr;
+        *image++ = sblock->sizeof_size;
+        *image++ = sblock->status_flags;
 
-            /* Encode the base address */
-            H5F_addr_encode(f, &p, sblock->base_addr);
+        /* Encode the base address */
+        H5F_addr_encode(f, &image, sblock->base_addr);
 
-            /* Encode the address of the superblock extension */
-            H5F_addr_encode(f, &p, sblock->ext_addr);
+        /* Encode the address of the superblock extension */
+        H5F_addr_encode(f, &image, sblock->ext_addr);
 
-            /* At this point in time, the EOF value itself may
-             * not be reflective of the file's size, since we'll eventually
-             * truncate it to match the EOA value. As such, use the EOA value
-             * in its place, knowing that the current EOF value will
-             * ultimately match it. */
-            if ((rel_eof = H5FD_get_eoa(f->shared->lf, H5FD_MEM_SUPER)) == HADDR_UNDEF)
-                HGOTO_ERROR(H5E_RESOURCE, H5E_CANTGET, FAIL, "driver get_eoa request failed")
-            H5F_addr_encode(f, &p, (rel_eof + sblock->base_addr));
+        /* At this point in time, the EOF value itself may
+         * not be reflective of the file's size, since we'll eventually
+         * truncate it to match the EOA value. As such, use the EOA value
+         * in its place, knowing that the current EOF value will
+         * ultimately match it. */
+        if ((rel_eof = H5FD_get_eoa(f->shared->lf, H5FD_MEM_SUPER)) == HADDR_UNDEF)
+            HGOTO_ERROR(H5E_RESOURCE, H5E_CANTGET, FAIL, "driver get_eoa request failed")
+        H5F_addr_encode(f, &image, (rel_eof + sblock->base_addr));
 
-            /* Retrieve information for root group */
-            if(NULL == (root_oloc = H5G_oloc(f->shared->root_grp)))
-                HGOTO_ERROR(H5E_FILE, H5E_CANTINIT, FAIL, "unable to retrieve root group information")
+        /* Retrieve information for root group */
+        if(NULL == (root_oloc = H5G_oloc(f->shared->root_grp)))
+            HGOTO_ERROR(H5E_FILE, H5E_CANTINIT, FAIL, "unable to retrieve root group information")
 
-            /* Encode address of root group's object header */
-            H5F_addr_encode(f, &p, root_oloc->addr);
+        /* Encode address of root group's object header */
+        H5F_addr_encode(f, &image, root_oloc->addr);
 
-            /* Compute superblock checksum */
-            chksum = H5_checksum_metadata(buf, ((size_t)H5F_SUPERBLOCK_SIZE(sblock->super_vers, f) - H5F_SIZEOF_CHKSUM), 0);
+        /* Compute superblock checksum */
+        chksum = H5_checksum_metadata(_image, ((size_t)H5F_SUPERBLOCK_SIZE(sblock) - H5F_SIZEOF_CHKSUM), 0);
 
-            /* Superblock checksum */
-            UINT32ENCODE(p, chksum);
+        /* Superblock checksum */
+        UINT32ENCODE(image, chksum);
 
-            /* Sanity check */
-            HDassert((size_t)(p - buf) == (size_t)H5F_SUPERBLOCK_SIZE(sblock->super_vers, f));
-        } /* end else */
+        /* Sanity check */
+        HDassert((size_t)(image - (uint8_t *)_image) == (size_t)H5F_SUPERBLOCK_SIZE(sblock));
+    } /* end else */
 
-        /* Retrieve the total size of the superblock info */
-        H5_CHECKED_ASSIGN(superblock_size, size_t, (p - buf), ptrdiff_t);
+    /* Sanity check */
+    HDassert((size_t)(image - (uint8_t *)_image) <= len);
 
-        /* Double check we didn't overrun the block (unlikely) */
-        HDassert(superblock_size <= sizeof(buf));
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* H5F__cache_superblock_serialize() */
 
-        /* Get the DXPL plist object for DXPL ID */
-        if(NULL == (dxpl = (H5P_genplist_t *)H5I_object(dxpl_id)))
-            HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "can't get property list")
+
+/*-------------------------------------------------------------------------
+ * Function:	H5F__cache_superblock_free_icr
+ *
+ * Purpose:	Destroy/release an "in core representation" of a data
+ *              structure
+ *
+ * Note:	The metadata cache sets the object's cache_info.magic to
+ *		H5C__H5C_CACHE_ENTRY_T_BAD_MAGIC before calling a free_icr
+ *		callback (checked in assert).
+ *
+ * Return:	Non-negative on success/Negative on failure
+ *
+ * Programmer:	Quincey Koziol
+ *              koziol@hdfgroup.org
+ *              July 20, 2013
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+H5F__cache_superblock_free_icr(void *_thing)
+{
+    H5F_super_t *sblock = (H5F_super_t *)_thing;        /* Pointer to the object */
+    herr_t ret_value = SUCCEED;         /* Return value */
 
-        /* Write superblock */
-        /* (always at relative address 0) */
-        if(H5FD_write(f->shared->lf, dxpl, H5FD_MEM_SUPER, (haddr_t)0, superblock_size, buf) < 0)
-            HGOTO_ERROR(H5E_IO, H5E_WRITEERROR, FAIL, "unable to write superblock")
+    FUNC_ENTER_STATIC
 
-        /* Check for newer version of superblock format & superblock extension */
-        if(sblock->super_vers >= HDF5_SUPERBLOCK_VERSION_2 && H5F_addr_defined(sblock->ext_addr)) {
-            H5O_loc_t 	ext_loc;        /* "Object location" for superblock extension */
+    /* Sanity check */
+    HDassert(sblock);
+    HDassert(sblock->cache_info.magic == H5C__H5C_CACHE_ENTRY_T_BAD_MAGIC);
+    HDassert(sblock->cache_info.type == H5AC_SUPERBLOCK);
 
-            /* Open the superblock extension's object header */
-            if(H5F_super_ext_open(f, sblock->ext_addr, &ext_loc) < 0)
-                HGOTO_ERROR(H5E_FILE, H5E_CANTOPENOBJ, FAIL, "unable to open file's superblock extension")
+    /* Destroy superblock */
+    if(H5F__super_free(sblock) < 0)
+        HGOTO_ERROR(H5E_BTREE, H5E_CANTFREE, FAIL, "unable to free superblock")
 
-            /* Check for ignoring the driver info for this file */
-            if(!H5F_HAS_FEATURE(f, H5FD_FEAT_IGNORE_DRVRINFO)) {
-                /* Check for driver info message */
-                H5_CHECKED_ASSIGN(driver_size, size_t, H5FD_sb_size(f->shared->lf), hsize_t);
-                if(driver_size > 0) {
-                    H5O_drvinfo_t drvinfo;      /* Driver info */
-                    uint8_t dbuf[H5F_MAX_DRVINFOBLOCK_SIZE];  /* Driver info block encoding buffer */
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* H5F__cache_superblock_free_icr() */
 
-                    /* Sanity check */
-                    HDassert(driver_size <= H5F_MAX_DRVINFOBLOCK_SIZE);
+
+/*-------------------------------------------------------------------------
+ * Function:    H5F__cache_drvrinfo_get_load_size
+ *
+ * Purpose:     Compute the size of the data structure on disk.
+ *
+ * Return:      Non-negative on success/Negative on failure
+ *
+ * Programmer:  Quincey Koziol
+ *              koziol@hdfgroup.org
+ *              July 20, 2013
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+H5F__cache_drvrinfo_get_load_size(const void H5_ATTR_UNUSED *udata, size_t *image_len)
+{
+    FUNC_ENTER_STATIC_NOERR
 
-                    /* Encode driver-specific data */
-                    if(H5FD_sb_encode(f->shared->lf, drvinfo.name, dbuf) < 0)
-                        HGOTO_ERROR(H5E_FILE, H5E_CANTINIT, FAIL, "unable to encode driver information")
+    /* Check arguments */
+    HDassert(image_len);
 
-                    /* Write driver info information to the superblock extension */
-                    drvinfo.len = driver_size;
-                    drvinfo.buf = dbuf;
-                    if(H5O_msg_write(&ext_loc, H5O_DRVINFO_ID, H5O_MSG_FLAG_DONTSHARE, H5O_UPDATE_TIME, &drvinfo, dxpl_id) < 0)
-                        HGOTO_ERROR(H5E_FILE, H5E_WRITEERROR, FAIL, "unable to update driver info header message")
+    /* Set the initial image length size */
+    *image_len = H5F_DRVINFOBLOCK_HDR_SIZE;     /* Fixed size portion of driver info block */
 
-                } /* end if */
+    FUNC_LEAVE_NOAPI(SUCCEED)
+} /* end H5F__cache_drvrinfo_get_load_size() */
 
-            } /* end if */
+
+/*-------------------------------------------------------------------------
+ * Function:	H5F__cache_drvrinfo_deserialize
+ *
+ * Purpose:	Loads an object from the disk.
+ *
+ * Return:	Success:	Pointer to a new B-tree.
+ *		Failure:	NULL
+ *
+ * Programmer:	Quincey Koziol
+ *		koziol@hdfgroup.org
+ *		July 20 2013
+ *
+ *-------------------------------------------------------------------------
+ */
+static void *
+H5F__cache_drvrinfo_deserialize(const void *_image, size_t len, void *_udata,
+    hbool_t H5_ATTR_UNUSED *dirty)
+{
+    H5O_drvinfo_t       *drvinfo = NULL; /* Driver info */
+    H5F_drvrinfo_cache_ud_t *udata = (H5F_drvrinfo_cache_ud_t *)_udata;     /* User data */
+    const uint8_t	*image = (const uint8_t *)_image;       /* Pointer into raw data buffer */
+    char                drv_name[9];    /* Name of driver */
+    unsigned            drv_vers;       /* Version of driver info block */
+    H5O_drvinfo_t       *ret_value;     /* Return value */
 
-            /* Close the superblock extension object header */
-            if(H5F_super_ext_close(f, &ext_loc, dxpl_id, FALSE) < 0)
-                HGOTO_ERROR(H5E_FILE, H5E_CANTCLOSEOBJ, FAIL, "unable to close file's superblock extension")
-        } /* end if */
+    FUNC_ENTER_STATIC
+
+    /* Sanity check */
+    HDassert(image);
+    HDassert(len >= H5F_DRVINFOBLOCK_HDR_SIZE);
+    HDassert(udata);
+    HDassert(udata->f);
+
+    /* Allocate space for the driver info */
+    if(NULL == (drvinfo = (H5O_drvinfo_t *)H5MM_calloc(sizeof(H5O_drvinfo_t))))
+	HGOTO_ERROR(H5E_FILE, H5E_CANTALLOC, NULL, "memory allocation failed for driver info message")
+
+    /* Version number */
+    drv_vers = *image++;
+    if(drv_vers != HDF5_DRIVERINFO_VERSION_0)
+        HGOTO_ERROR(H5E_FILE, H5E_BADVALUE, NULL, "bad driver information block version number")
+
+    image += 3; /* reserved bytes */
+
+    /* Driver info size */
+    UINT32DECODE(image, drvinfo->len);
+
+    /* Driver name and/or version */
+    HDstrncpy(drv_name, (const char *)image, (size_t)8);
+    drv_name[8] = '\0';
+    image += 8; /* advance past name/version */
+
+    /* Handle metadata cache retry for variable-sized portion of the driver info block */
+    if(len != (H5F_DRVINFOBLOCK_HDR_SIZE + drvinfo->len)) {
+        /* Sanity check */
+        HDassert(len == H5F_DRVINFOBLOCK_HDR_SIZE);
+
+        /* extend the eoa if required so that we can read the complete driver info block */
+        {
+            haddr_t eoa;
+            haddr_t min_eoa;
+
+            /* get current eoa... */
+	    if ((eoa = H5FD_get_eoa(udata->f->shared->lf, H5FD_MEM_SUPER)) == HADDR_UNDEF)
+                HGOTO_ERROR(H5E_RESOURCE, H5E_CANTGET, NULL, "driver get_eoa request failed")
+
+            /* ... if it is too small, extend it. */
+            min_eoa = udata->driver_addr + H5F_DRVINFOBLOCK_HDR_SIZE + drvinfo->len;
+
+            if ( H5F_addr_gt(min_eoa, eoa) )
+                if(H5FD_set_eoa(udata->f->shared->lf, H5FD_MEM_SUPER, min_eoa) < 0)
+                    HGOTO_ERROR(H5E_FILE, H5E_CANTINIT, NULL, \
+                        "set end of space allocation request failed")
+        }        
 
-        /* Reset the dirty flag.  */
-        sblock->cache_info.is_dirty = FALSE;
+    } /* end if */
+    else {
+        /* Validate and decode driver information */
+        if(H5FD_sb_load(udata->f->shared->lf, drv_name, image) < 0)
+            HGOTO_ERROR(H5E_FILE, H5E_CANTDECODE, NULL, "unable to decode driver information")
     } /* end if */
 
-    if(destroy)
-        if(H5F_sblock_dest(f, sblock) < 0)
-            HGOTO_ERROR(H5E_FSPACE, H5E_CLOSEERROR, FAIL, "can't close superblock")
+    /* Sanity check */
+    HDassert((size_t)(image - (const uint8_t *)_image) <= len);
+
+    /* Set return value */
+    ret_value = drvinfo;
 
 done:
+    /* Release the [possibly partially initialized] driver info message on error */
+    if(!ret_value && drvinfo)
+        H5MM_xfree(drvinfo);
+
     FUNC_LEAVE_NOAPI(ret_value)
-} /* end H5F_sblock_flush() */
+} /* end H5F__cache_drvrinfo_deserialize() */
 
 
 /*-------------------------------------------------------------------------
- * Function:    H5F_sblock_dest
+ * Function:    H5F__cache_drvrinfo_image_len
  *
- * Purpose:     Frees memory used by the superblock.
+ * Purpose:     Compute the size of the data structure on disk.
  *
  * Return:      Non-negative on success/Negative on failure
  *
- * Programmer:  Mike McGreevy
- *              April 8, 2009
+ * Programmer:  Quincey Koziol
+ *              koziol@hdfgroup.org
+ *              July 20, 2013
  *
  *-------------------------------------------------------------------------
  */
 static herr_t
-H5F_sblock_dest(H5F_t H5_ATTR_UNUSED *f, H5F_super_t* sblock)
+H5F__cache_drvrinfo_image_len(const void *_thing, size_t *image_len,
+    hbool_t H5_ATTR_UNUSED *compressed_ptr, size_t H5_ATTR_UNUSED *compressed_image_len_ptr)
 {
-    herr_t ret_value = SUCCEED;         /* Return value */
+    const H5O_drvinfo_t *drvinfo = (const H5O_drvinfo_t *)_thing;       /* Pointer to the object */
 
-    FUNC_ENTER_NOAPI_NOINIT
+    FUNC_ENTER_STATIC_NOERR
 
-    /* Sanity check */
-    HDassert(sblock);
+    /* Check arguments */
+    HDassert(drvinfo);
+    HDassert(drvinfo->cache_info.magic == H5C__H5C_CACHE_ENTRY_T_MAGIC);
+    HDassert(drvinfo->cache_info.type == H5AC_DRVRINFO);
+    HDassert(image_len);
+    HDassert(compressed_ptr);
 
-    /* Free superblock */
-    if(H5F__super_free(sblock) < 0)
-        HGOTO_ERROR(H5E_FILE, H5E_CANTFREE, FAIL, "unable to destroy superblock")
+    /* Set the image length size */
+    *image_len = (size_t)(H5F_DRVINFOBLOCK_HDR_SIZE +   /* Fixed-size portion of driver info block */
+        drvinfo->len);                                  /* Variable-size portion of driver info block */
 
-done:
-    FUNC_LEAVE_NOAPI(ret_value)
-} /* end H5F_sblock_dest() */
+    FUNC_LEAVE_NOAPI(SUCCEED)
+} /* end H5F__cache_drvrinfo_image_len() */
 
 
 /*-------------------------------------------------------------------------
- * Function:    H5F_sblock_clear
+ * Function:	H5F__cache_drvrinfo_serialize
  *
- * Purpose:     Mark the superblock as no longer being dirty.
+ * Purpose:	Flushes a dirty object to disk.
  *
- * Return:      Non-negative on success/Negative on failure
+ * Return:	Non-negative on success/Negative on failure
  *
- * Programmer:  Mike McGreevy
- *              April 8, 2009
+ * Programmer:	Quincey Koziol
+ *		koziol@hdfgroup.org
+ *		July 20 2013
  *
  *-------------------------------------------------------------------------
  */
 static herr_t
-H5F_sblock_clear(H5F_t *f, H5F_super_t *sblock, hbool_t destroy)
+H5F__cache_drvrinfo_serialize(const H5F_t *f, void *_image, size_t len,
+    void *_thing)
 {
-    herr_t ret_value = SUCCEED;         /* Return value */
+    H5O_drvinfo_t *drvinfo = (H5O_drvinfo_t *)_thing;   /* Pointer to the object */
+    uint8_t *image = (uint8_t *)_image;         /* Pointer into raw data buffer */
+    uint8_t *dbuf;              /* Pointer to beginning of driver info */
+    herr_t ret_value = SUCCEED; /* Return value */
 
-    FUNC_ENTER_NOAPI_NOINIT
+    FUNC_ENTER_STATIC
 
-    /*
-     * Check arguments.
-     */
-    HDassert(sblock);
+    /* check arguments */
+    HDassert(f);
+    HDassert(image);
+    HDassert(drvinfo);
+    HDassert(drvinfo->cache_info.magic == H5C__H5C_CACHE_ENTRY_T_MAGIC);
+    HDassert(drvinfo->cache_info.type == H5AC_DRVRINFO);
+    HDassert(len == (size_t)(H5F_DRVINFOBLOCK_HDR_SIZE + drvinfo->len));
+
+    /* Save pointer to beginning of driver info */
+    dbuf = image;
+
+    /* Encode the driver information block */
+    *image++ = HDF5_DRIVERINFO_VERSION_0; /* Version */
+    *image++ = 0; /* reserved */
+    *image++ = 0; /* reserved */
+    *image++ = 0; /* reserved */
+
+    /* Driver info size, excluding header */
+    UINT32ENCODE(image, drvinfo->len);
 
-    /* Reset the dirty flag.  */
-    sblock->cache_info.is_dirty = FALSE;
+    /* Encode driver-specific data */
+    if(H5FD_sb_encode(f->shared->lf, (char *)image, dbuf + H5F_DRVINFOBLOCK_HDR_SIZE) < 0)
+        HGOTO_ERROR(H5E_FILE, H5E_CANTINIT, FAIL, "unable to encode driver information")
 
-    if(destroy)
-        if(H5F_sblock_dest(f, sblock) < 0)
-            HGOTO_ERROR(H5E_FILE, H5E_CANTFREE, FAIL, "unable to delete superblock")
+    /* Advance buffer pointer past name & variable-sized portion of driver info */
+    image += 8 + drvinfo->len;
+
+    /* Sanity check */
+    HDassert((size_t)(image - (uint8_t *)_image) <= len);
 
 done:
     FUNC_LEAVE_NOAPI(ret_value)
-} /* end H5F_sblock_clear() */
+} /* H5F__cache_drvrinfo_serialize() */
 
 
 /*-------------------------------------------------------------------------
- * Function:    H5F_sblock_size
+ * Function:	H5F__cache_drvrinfo_free_icr
  *
- * Purpose:     Returns the size of the superblock encoded on disk.
+ * Purpose:	Destroy/release an "in core representation" of a data
+ *              structure
  *
- * Return:      Non-negative on success/Negative on failure
+ * Note:	The metadata cache sets the object's cache_info.magic to
+ *		H5C__H5C_CACHE_ENTRY_T_BAD_MAGIC before calling a free_icr
+ *		callback (checked in assert).
  *
- * Programmer:  Mike McGreevy
- *              April 8, 2009
+ * Return:	Non-negative on success/Negative on failure
+ *
+ * Programmer:	Quincey Koziol
+ *              koziol@hdfgroup.org
+ *              July 20, 2013
  *
  *-------------------------------------------------------------------------
  */
 static herr_t
-H5F_sblock_size(const H5F_t *f, const H5F_super_t *sblock, size_t *size_ptr)
+H5F__cache_drvrinfo_free_icr(void *_thing)
 {
-    FUNC_ENTER_NOAPI_NOINIT_NOERR
+    H5O_drvinfo_t *drvinfo = (H5O_drvinfo_t *)_thing;    /* Pointer to the object */
 
-    /* check arguments */
-    HDassert(f);
-    HDassert(sblock);
-    HDassert(size_ptr);
+    FUNC_ENTER_STATIC_NOERR
+
+    /* Check arguments */
+    HDassert(drvinfo);
+    HDassert(drvinfo->cache_info.magic == H5C__H5C_CACHE_ENTRY_T_BAD_MAGIC);
+    HDassert(drvinfo->cache_info.type == H5AC_DRVRINFO);
 
-    /* Set size value */
-    *size_ptr = (size_t)H5F_SUPERBLOCK_SIZE(sblock->super_vers, f);
+    /* Destroy driver info message */
+    H5MM_xfree(drvinfo);
 
     FUNC_LEAVE_NOAPI(SUCCEED)
-} /* end H5F_sblock_size() */
+} /* H5F__cache_drvrinfo_free_icr() */
 
diff --git a/src/H5Gcache.c b/src/H5Gcache.c
index bedceb6..8dfecb1 100644
--- a/src/H5Gcache.c
+++ b/src/H5Gcache.c
@@ -46,7 +46,6 @@
 /****************/
 
 #define H5G_NODE_VERS           1       /* Symbol table node version number   */
-#define H5G_NODE_BUF_SIZE       512     /* Size of stack buffer for serialized nodes */
 
 
 /******************/
@@ -64,12 +63,14 @@
 /********************/
 
 /* Metadata cache (H5AC) callbacks */
-static H5G_node_t *H5G_node_load(H5F_t *f, hid_t dxpl_id, haddr_t addr, void *udata);
-static herr_t H5G_node_flush(H5F_t *f, hid_t dxpl_id, hbool_t destroy, haddr_t addr,
-			     H5G_node_t *sym, unsigned *flags_ptr);
-static herr_t H5G_node_dest(H5F_t *f, H5G_node_t *sym);
-static herr_t H5G_node_clear(H5F_t *f, H5G_node_t *sym, hbool_t destroy);
-static herr_t H5G_node_size(const H5F_t *f, const H5G_node_t *sym, size_t *size_ptr);
+static herr_t H5G__cache_node_get_load_size(const void *udata, size_t *image_len);
+static void *H5G__cache_node_deserialize(const void *image, size_t len,
+    void *udata, hbool_t *dirty);
+static herr_t H5G__cache_node_image_len(const void *thing, size_t *image_len,
+    hbool_t *compressed_ptr, size_t *compressed_image_len_ptr);
+static herr_t H5G__cache_node_serialize(const H5F_t *f, void *image,
+    size_t len, void *thing);
+static herr_t H5G__cache_node_free_icr(void *thing);
 
 
 /*********************/
@@ -88,13 +89,19 @@ static herr_t H5G_node_size(const H5F_t *f, const H5G_node_t *sym, size_t *size_
 
 /* Symbol table nodes inherit cache-like properties from H5AC */
 const H5AC_class_t H5AC_SNODE[1] = {{
-    H5AC_SNODE_ID,
-    (H5AC_load_func_t)H5G_node_load,
-    (H5AC_flush_func_t)H5G_node_flush,
-    (H5AC_dest_func_t)H5G_node_dest,
-    (H5AC_clear_func_t)H5G_node_clear,
-    (H5AC_notify_func_t)NULL,
-    (H5AC_size_func_t)H5G_node_size,
+    H5AC_SNODE_ID,                      /* Metadata client ID */
+    "Symbol table node",                /* Metadata client name (for debugging) */
+    H5FD_MEM_BTREE,                     /* File space memory type for client */
+    H5AC__CLASS_NO_FLAGS_SET,           /* Client class behavior flags */
+    H5G__cache_node_get_load_size,      /* 'get_load_size' callback */
+    H5G__cache_node_deserialize,        /* 'deserialize' callback */
+    H5G__cache_node_image_len,          /* 'image_len' callback */
+    NULL,                               /* 'pre_serialize' callback */
+    H5G__cache_node_serialize,          /* 'serialize' callback */
+    NULL,                               /* 'notify' callback */
+    H5G__cache_node_free_icr,           /* 'free_icr' callback */
+    NULL,			        /* 'clear' callback */
+    NULL,                               /* 'fsf_size' callback */
 }};
 
 
@@ -106,42 +113,80 @@ H5FL_SEQ_EXTERN(H5G_entry_t);
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5G_node_load
+ * Function:    H5G__cache_node_get_load_size()
  *
- * Purpose:	Loads a symbol table node from the file.
+ * Purpose:	Determine the size of the on disk image of the node, and 
+ *		return this value in *image_len.
  *
- * Return:	Success:	Ptr to the new table.
+ *		Note that this computation requires access to the file pointer,
+ *		which is not provided in the parameter list for this callback.
+ *		Finesse this issue by passing in the file pointer twice to the
+ *		H5AC_protect() call -- once as the file pointer proper, and 
+ *		again as the user data.
+ *      
+ * Return:      Success:        SUCCEED
+ *              Failure:        FAIL
  *
- *		Failure:	NULL
- *
- * Programmer:	Robb Matzke
- *		matzke@llnl.gov
- *		Jun 23 1997
+ * Programmer:  John Mainzer
+ *              7/21/14
  *
  *-------------------------------------------------------------------------
  */
-static H5G_node_t *
-H5G_node_load(H5F_t *f, hid_t dxpl_id, haddr_t addr, void *udata)
+static herr_t
+H5G__cache_node_get_load_size(const void *_udata, size_t *image_len)
 {
-    H5G_node_t		   *sym = NULL;
-    H5WB_t                 *wb = NULL;     /* Wrapped buffer for node data */
-    uint8_t                 node_buf[H5G_NODE_BUF_SIZE]; /* Buffer for node */
-    uint8_t		   *node;           /* Pointer to node buffer */
-    const uint8_t	   *p;
-    H5G_node_t		   *ret_value;	/*for error handling */
-
-    FUNC_ENTER_NOAPI_NOINIT
-
-    /*
-     * Check arguments.
-     */
+    const H5F_t	       *f = (const H5F_t *)_udata;   /* User data for callback */
+
+    FUNC_ENTER_STATIC_NOERR
+
+    /* Sanity checks */
     HDassert(f);
-    HDassert(H5F_addr_defined(addr));
-    HDassert(udata);
+    HDassert(image_len);
+
+    /* report image length */
+    *image_len = (size_t)(H5G_NODE_SIZE(f));
+
+    FUNC_LEAVE_NOAPI(SUCCEED)
+} /* end H5G__cache_node_get_load_size() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:    H5G__cache_node_deserialize
+ *
+ * Purpose:	Given a buffer containing the on disk image of a symbol table
+ *		node, allocate an instance of H5G_node_t, load the contence of the
+ *		image into it, and return a pointer to the instance.
+ *
+ *		Note that deserializing the image requires access to the file 
+ *		pointer, which is not included in the parameter list for this 
+ *		callback.  Finesse this issue by passing in the file pointer 
+ *		twice to the H5AC_protect() call -- once as the file pointer 
+ *		proper, and again as the user data
+ *
+ * Return:      Success:        Pointer to in core representation
+ *              Failure:        NULL
+ *
+ * Programmer:  John Mainzer
+ *              6/21/14
+ *
+ *-------------------------------------------------------------------------
+ */
+static void *
+H5G__cache_node_deserialize(const void *_image, size_t len, void *_udata,
+    hbool_t H5_ATTR_UNUSED *dirty)
+{
+    H5F_t                  *f = (H5F_t *)_udata;        /* User data for callback */
+    H5G_node_t             *sym = NULL; /* Symbol table node created */
+    const uint8_t          *image = (const uint8_t *)_image;    /* Pointer to image to deserialize */
+    void *                  ret_value;  /* Return value */
 
-    /*
-     * Initialize variables.
-     */
+    FUNC_ENTER_STATIC
+
+    /* Sanity checks */
+    HDassert(image);
+    HDassert(len > 0);
+    HDassert(f);
+    HDassert(dirty);
 
     /* Allocate symbol table data structures */
     if(NULL == (sym = H5FL_CALLOC(H5G_node_t)))
@@ -150,262 +195,175 @@ H5G_node_load(H5F_t *f, hid_t dxpl_id, haddr_t addr, void *udata)
     if(NULL == (sym->entry = H5FL_SEQ_CALLOC(H5G_entry_t, (size_t)(2 * H5F_SYM_LEAF_K(f)))))
         HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, NULL, "memory allocation failed")
 
-    /* Wrap the local buffer for serialized node info */
-    if(NULL == (wb = H5WB_wrap(node_buf, sizeof(node_buf))))
-        HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, NULL, "can't wrap buffer")
-
-    /* Get a pointer to a buffer that's large enough for node */
-    if(NULL == (node = (uint8_t *)H5WB_actual(wb, sym->node_size)))
-        HGOTO_ERROR(H5E_SYM, H5E_NOSPACE, NULL, "can't get actual buffer")
-
-    /* Read the serialized symbol table node. */
-    if(H5F_block_read(f, H5FD_MEM_BTREE, addr, sym->node_size, dxpl_id, node) < 0)
-	HGOTO_ERROR(H5E_SYM, H5E_READERROR, NULL, "unable to read symbol table node")
-
-    /* Get temporary pointer to serialized node */
-    p = node;
-
     /* magic */
-    if(HDmemcmp(p, H5G_NODE_MAGIC, (size_t)H5_SIZEOF_MAGIC))
-        HGOTO_ERROR(H5E_SYM, H5E_CANTLOAD, NULL, "bad symbol table node signature")
-    p += H5_SIZEOF_MAGIC;
+    if(HDmemcmp(image, H5G_NODE_MAGIC, (size_t)H5_SIZEOF_MAGIC))
+        HGOTO_ERROR(H5E_SYM, H5E_BADVALUE, NULL, "bad symbol table node signature")
+    image += H5_SIZEOF_MAGIC;
 
     /* version */
-    if(H5G_NODE_VERS != *p++)
-        HGOTO_ERROR(H5E_SYM, H5E_CANTLOAD, NULL, "bad symbol table node version")
+    if(H5G_NODE_VERS != *image++)
+        HGOTO_ERROR(H5E_SYM, H5E_VERSION, NULL, "bad symbol table node version")
 
     /* reserved */
-    p++;
+    image++;
 
     /* number of symbols */
-    UINT16DECODE(p, sym->nsyms);
+    UINT16DECODE(image, sym->nsyms);
 
     /* entries */
-    if(H5G__ent_decode_vec(f, &p, sym->entry, sym->nsyms) < 0)
+    if(H5G__ent_decode_vec(f, &image, sym->entry, sym->nsyms) < 0)
         HGOTO_ERROR(H5E_SYM, H5E_CANTLOAD, NULL, "unable to decode symbol table entries")
 
     /* Set return value */
     ret_value = sym;
 
 done:
-    /* Release resources */
-    if(wb && H5WB_unwrap(wb) < 0)
-        HDONE_ERROR(H5E_SYM, H5E_CLOSEERROR, NULL, "can't close wrapped buffer")
     if(!ret_value)
         if(sym && H5G__node_free(sym) < 0)
             HDONE_ERROR(H5E_SYM, H5E_CANTFREE, NULL, "unable to destroy symbol table node")
 
     FUNC_LEAVE_NOAPI(ret_value)
-} /* end H5G_node_load() */
+} /* end H5G__cache_node_deserialize() */
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5G_node_flush
+ * Function:    H5G__cache_node_image_len
  *
- * Purpose:	Flush a symbol table node to disk.
+ * Purpose:     Compute the size of the data structure on disk and return
+ *              it in *image_len.
  *
- * Return:	Non-negative on success/Negative on failure
+ * Return:      Success:        SUCCEED
+ *              Failure:        FAIL
  *
- * Programmer:	Robb Matzke
- *		matzke@llnl.gov
- *		Jun 23 1997
+ * Programmer:  John Mainzer
+ *              6/21/14
  *
  *-------------------------------------------------------------------------
  */
 static herr_t
-H5G_node_flush(H5F_t *f, hid_t dxpl_id, hbool_t destroy, haddr_t addr, H5G_node_t *sym, unsigned H5_ATTR_UNUSED * flags_ptr)
+H5G__cache_node_image_len(const void *_thing, size_t *image_len,
+    hbool_t H5_ATTR_UNUSED *compressed_ptr, size_t H5_ATTR_UNUSED *compressed_image_len_ptr)
 {
-    H5WB_t     *wb = NULL;     /* Wrapped buffer for node data */
-    uint8_t     node_buf[H5G_NODE_BUF_SIZE]; /* Buffer for node */
-    herr_t      ret_value = SUCCEED;       /* Return value */
+    const H5G_node_t *sym = (const H5G_node_t *)_thing; /* Pointer to object */
 
-    FUNC_ENTER_NOAPI_NOINIT
+    FUNC_ENTER_STATIC_NOERR
 
-    /*
-     * Check arguments.
-     */
-    HDassert(f);
-    HDassert(H5F_addr_defined(addr));
+    /* Sanity checks */
     HDassert(sym);
+    HDassert(sym->cache_info.magic == H5C__H5C_CACHE_ENTRY_T_MAGIC);
+    HDassert(sym->cache_info.type == H5AC_SNODE);
+    HDassert(image_len);
 
-    /*
-     * Write the symbol node to disk.
-     */
-    if(sym->cache_info.is_dirty) {
-        uint8_t	*node;          /* Pointer to node buffer */
-        uint8_t	*p;             /* Pointer into raw data buffer */
-
-        /* Wrap the local buffer for serialized node info */
-        if(NULL == (wb = H5WB_wrap(node_buf, sizeof(node_buf))))
-            HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "can't wrap buffer")
-
-        /* Get a pointer to a buffer that's large enough for node */
-        if(NULL == (node = (uint8_t *)H5WB_actual(wb, sym->node_size)))
-            HGOTO_ERROR(H5E_SYM, H5E_NOSPACE, FAIL, "can't get actual buffer")
-
-        /* Get temporary pointer to serialized symbol table node */
-        p = node;
-
-        /* magic number */
-        HDmemcpy(p, H5G_NODE_MAGIC, (size_t)H5_SIZEOF_MAGIC);
-        p += H5_SIZEOF_MAGIC;
-
-        /* version number */
-        *p++ = H5G_NODE_VERS;
-
-        /* reserved */
-        *p++ = 0;
-
-        /* number of symbols */
-        UINT16ENCODE(p, sym->nsyms);
-
-        /* entries */
-        if(H5G__ent_encode_vec(f, &p, sym->entry, sym->nsyms) < 0)
-            HGOTO_ERROR(H5E_SYM, H5E_CANTENCODE, FAIL, "can't serialize")
-        HDmemset(p, 0, sym->node_size - (size_t)(p - node));
-
-	/* Write the serialized symbol table node. */
-        if(H5F_block_write(f, H5FD_MEM_BTREE, addr, sym->node_size, dxpl_id, node) < 0)
-            HGOTO_ERROR(H5E_SYM, H5E_WRITEERROR, FAIL, "unable to write symbol table node to the file")
-
-        /* Reset the node's dirty flag */
-        sym->cache_info.is_dirty = FALSE;
-    } /* end if */
+    *image_len = sym->node_size;
 
-    /*
-     * Destroy the symbol node?	 This might happen if the node is being
-     * preempted from the cache.
-     */
-    if(destroy)
-        if(H5G_node_dest(f, sym) < 0)
-	    HGOTO_ERROR(H5E_SYM, H5E_CANTFREE, FAIL, "unable to destroy symbol table node")
+    FUNC_LEAVE_NOAPI(SUCCEED)
+} /* end H5G__cache_node_image_len() */
 
-done:
-    /* Release resources */
-    if(wb && H5WB_unwrap(wb) < 0)
-        HDONE_ERROR(H5E_SYM, H5E_CLOSEERROR, FAIL, "can't close wrapped buffer")
 
-    FUNC_LEAVE_NOAPI(ret_value)
-} /* end H5G_node_flush() */
+/*************************************/
+/* no H5G__cache_node_pre_serialize() */
+/*************************************/
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5G_node_dest
+ * Function:    H5G__cache_node_serialize
  *
- * Purpose:	Destroy a symbol table node in memory.
+ * Purpose:	Given a correctly sized buffer and an instace of H5G_node_t,
+ *		serialize the contents of the instance of H5G_node_t, and write
+ *		this data into the supplied buffer.  This buffer will be written
+ *		to disk.
  *
- * Return:	Non-negative on success/Negative on failure
+ * Return:      Success:        SUCCEED
+ *              Failure:        FAIL
  *
- * Programmer:	Quincey Koziol
- *		koziol@ncsa.uiuc.edu
- *		Jan 15 2003
+ * Programmer:  John Mainzer
+ *              7/21/14
  *
  *-------------------------------------------------------------------------
  */
 static herr_t
-H5G_node_dest(H5F_t *f, H5G_node_t *sym)
+H5G__cache_node_serialize(const H5F_t *f, void *_image, size_t len,
+    void *_thing)
 {
-    herr_t ret_value = SUCCEED;         /* Return value */
+    H5G_node_t *sym = (H5G_node_t *)_thing;     /* Pointer to object */
+    uint8_t    *image = (uint8_t *)_image;      /* Pointer into raw data buffer */
+    herr_t      ret_value = SUCCEED;    /* Return value */
 
-    FUNC_ENTER_NOAPI_NOINIT
+    FUNC_ENTER_STATIC
 
-    /*
-     * Check arguments.
-     */
+    /* Sanity checks */
     HDassert(f);
+    HDassert(image);
     HDassert(sym);
+    HDassert(sym->cache_info.magic == H5C__H5C_CACHE_ENTRY_T_MAGIC);
+    HDassert(sym->cache_info.type == H5AC_SNODE);
+    HDassert(len == sym->node_size);
 
-    /* Verify that node is clean */
-    HDassert(sym->cache_info.is_dirty == FALSE);
+    /* magic number */
+    HDmemcpy(image, H5G_NODE_MAGIC, (size_t)H5_SIZEOF_MAGIC);
+    image += H5_SIZEOF_MAGIC;
 
-    /* If we're going to free the space on disk, the address must be valid */
-    HDassert(!sym->cache_info.free_file_space_on_destroy || H5F_addr_defined(sym->cache_info.addr));
+    /* version number */
+    *image++ = H5G_NODE_VERS;
 
-    /* Check for freeing file space for symbol table node */
-    if(sym->cache_info.free_file_space_on_destroy) {
-        /* Release the space on disk */
-        /* (XXX: Nasty usage of internal DXPL value! -QAK) */
-        if(H5MF_xfree(f, H5FD_MEM_BTREE, H5AC_dxpl_id, sym->cache_info.addr, (hsize_t)sym->node_size) < 0)
-            HGOTO_ERROR(H5E_SYM, H5E_CANTFREE, FAIL, "unable to free symbol table node")
-    } /* end if */
+    /* reserved */
+    *image++ = 0;
 
-    /* Destroy symbol table node */
-    if(H5G__node_free(sym) < 0)
-        HGOTO_ERROR(H5E_SYM, H5E_CANTFREE, FAIL, "unable to destroy symbol table node")
+    /* number of symbols */
+    UINT16ENCODE(image, sym->nsyms);
+
+    /* entries */
+    if(H5G__ent_encode_vec(f, &image, sym->entry, sym->nsyms) < 0)
+        HGOTO_ERROR(H5E_SYM, H5E_CANTENCODE, FAIL, "can't serialize")
+
+    /* Clear rest of symbol table node */
+    HDmemset(image, 0, sym->node_size - (size_t)(image - (uint8_t *)_image));
 
 done:
     FUNC_LEAVE_NOAPI(ret_value)
-} /* end H5G_node_dest() */
+} /* end H5G__cache_node_serialize() */
+
+
+/***************************************/
+/* no H5G__cache_node_notify() function */
+/***************************************/
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5G_node_clear
+ * Function:    H5G__cache_node_free_icr
  *
- * Purpose:	Mark a symbol table node in memory as non-dirty.
+ * Purpose:	Destroys a symbol table node in memory.
  *
- * Return:	Non-negative on success/Negative on failure
+ * Note:	The metadata cache sets the object's cache_info.magic to
+ *		H5C__H5C_CACHE_ENTRY_T_BAD_MAGIC before calling a free_icr
+ *		callback (checked in assert).
  *
- * Programmer:	Quincey Koziol
- *		koziol@ncsa.uiuc.edu
- *		Mar 20 2003
+ * Return:      Success:        SUCCEED
+ *              Failure:        FAIL
+ *
+ * Programmer:  John Mainzer
+ *              6/21/14
  *
  *-------------------------------------------------------------------------
  */
 static herr_t
-H5G_node_clear(H5F_t *f, H5G_node_t *sym, hbool_t destroy)
+H5G__cache_node_free_icr(void *_thing)
 {
-    herr_t ret_value = SUCCEED;
+    H5G_node_t *sym = (H5G_node_t *)_thing;     /* Pointer to the object */
+    herr_t      ret_value = SUCCEED;    /* Return value */
 
-    FUNC_ENTER_NOAPI_NOINIT
+    FUNC_ENTER_STATIC
 
-    /*
-     * Check arguments.
-     */
+    /* Sanity checks */
     HDassert(sym);
+    HDassert(sym->cache_info.magic == H5C__H5C_CACHE_ENTRY_T_BAD_MAGIC);
+    HDassert(sym->cache_info.type == H5AC_SNODE);
 
-    /* Reset the node's dirty flag */
-    sym->cache_info.is_dirty = FALSE;
-
-    /*
-     * Destroy the symbol node?	 This might happen if the node is being
-     * preempted from the cache.
-     */
-    if(destroy)
-        if(H5G_node_dest(f, sym) < 0)
-	    HGOTO_ERROR(H5E_SYM, H5E_CANTFREE, FAIL, "unable to destroy symbol table node")
+    /* Destroy symbol table node */
+    if(H5G__node_free(sym) < 0)
+        HGOTO_ERROR(H5E_SYM, H5E_CANTFREE, FAIL, "unable to destroy symbol table node")
 
 done:
     FUNC_LEAVE_NOAPI(ret_value)
-} /* end H5G_node_clear() */
-
-
-/*-------------------------------------------------------------------------
- * Function:	H5G_node_size
- *
- * Purpose:	Compute the size in bytes of the specified instance of
- *		H5G_node_t on disk, and return it in *size_ptr.  On failure
- *		the value of size_ptr is undefined.
- *
- * Return:	Non-negative on success/Negative on failure
- *
- * Programmer:	John Mainzer
- *		5/13/04
- *
- *-------------------------------------------------------------------------
- */
-static herr_t
-H5G_node_size(const H5F_t H5_ATTR_UNUSED *f, const H5G_node_t *sym, size_t *size_ptr)
-{
-    FUNC_ENTER_NOAPI_NOINIT_NOERR
-
-    /*
-     * Check arguments.
-     */
-    HDassert(f);
-    HDassert(size_ptr);
-
-    *size_ptr = sym->node_size;
-
-    FUNC_LEAVE_NOAPI(SUCCEED)
-} /* H5G_node_size() */
+} /* end H5G__cache_node_free_icr() */
 
diff --git a/src/H5Gent.c b/src/H5Gent.c
index 3f243de..3809933 100644
--- a/src/H5Gent.c
+++ b/src/H5Gent.c
@@ -460,7 +460,7 @@ H5G__ent_convert(H5F_t *f, hid_t dxpl_id, H5HL_t *heap, const char *name,
                 targ_oloc.addr = lnk->u.hard.addr;
 
                 /* Get the object header */
-                if(NULL == (oh = H5O_protect(&targ_oloc, dxpl_id, H5AC_READ)))
+                if(NULL == (oh = H5O_protect(&targ_oloc, dxpl_id, H5AC__READ_ONLY_FLAG)))
                     HGOTO_ERROR(H5E_SYM, H5E_CANTPROTECT, FAIL, "unable to protect target object header")
 
                 /* Check if a symbol table message exists */
diff --git a/src/H5Gnode.c b/src/H5Gnode.c
index d695dac..cbb9a8e 100644
--- a/src/H5Gnode.c
+++ b/src/H5Gnode.c
@@ -541,7 +541,7 @@ H5G_node_found(H5F_t *f, hid_t dxpl_id, haddr_t addr, const void H5_ATTR_UNUSED
     /*
      * Load the symbol table node for exclusive access.
      */
-    if(NULL == (sn = (H5G_node_t *)H5AC_protect(f, dxpl_id, H5AC_SNODE, addr, f, H5AC_READ)))
+    if(NULL == (sn = (H5G_node_t *)H5AC_protect(f, dxpl_id, H5AC_SNODE, addr, f, H5AC__READ_ONLY_FLAG)))
 	HGOTO_ERROR(H5E_SYM, H5E_CANTLOAD, FAIL, "unable to protect symbol table node")
 
     /* Get base address of heap */
@@ -647,7 +647,7 @@ H5G_node_insert(H5F_t *f, hid_t dxpl_id, haddr_t addr,
     /*
      * Load the symbol node.
      */
-    if(NULL == (sn = (H5G_node_t *)H5AC_protect(f, dxpl_id, H5AC_SNODE, addr, f, H5AC_WRITE)))
+    if(NULL == (sn = (H5G_node_t *)H5AC_protect(f, dxpl_id, H5AC_SNODE, addr, f, H5AC__NO_FLAGS_SET)))
 	HGOTO_ERROR(H5E_SYM, H5E_CANTLOAD, H5B_INS_ERROR, "unable to protect symbol table node")
 
     /* Get base address of heap */
@@ -691,7 +691,7 @@ H5G_node_insert(H5F_t *f, hid_t dxpl_id, haddr_t addr,
 	if(H5G_node_create(f, dxpl_id, H5B_INS_FIRST, NULL, NULL, NULL, new_node_p/*out*/) < 0)
 	    HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, H5B_INS_ERROR, "unable to split symbol table node")
 
-	if(NULL == (snrt = (H5G_node_t *)H5AC_protect(f, dxpl_id, H5AC_SNODE, *new_node_p, f, H5AC_WRITE)))
+	if(NULL == (snrt = (H5G_node_t *)H5AC_protect(f, dxpl_id, H5AC_SNODE, *new_node_p, f, H5AC__NO_FLAGS_SET)))
 	    HGOTO_ERROR(H5E_SYM, H5E_CANTLOAD, H5B_INS_ERROR, "unable to split symbol table node")
 
 	HDmemcpy(snrt->entry, sn->entry + H5F_SYM_LEAF_K(f),
@@ -808,7 +808,7 @@ H5G_node_remove(H5F_t *f, hid_t dxpl_id, haddr_t addr, void *_lt_key/*in,out*/,
     HDassert(udata && udata->common.heap);
 
     /* Load the symbol table */
-    if(NULL == (sn = (H5G_node_t *)H5AC_protect(f, dxpl_id, H5AC_SNODE, addr, f, H5AC_WRITE)))
+    if(NULL == (sn = (H5G_node_t *)H5AC_protect(f, dxpl_id, H5AC_SNODE, addr, f, H5AC__NO_FLAGS_SET)))
 	HGOTO_ERROR(H5E_SYM, H5E_CANTLOAD, H5B_INS_ERROR, "unable to protect symbol table node")
 
     /* "Normal" removal of a single entry from the symbol table node */
@@ -1001,7 +1001,7 @@ H5G__node_iterate(H5F_t *f, hid_t dxpl_id, const void H5_ATTR_UNUSED *_lt_key, h
     HDassert(udata && udata->heap);
 
     /* Protect the symbol table node & local heap while we iterate over entries */
-    if(NULL == (sn = (H5G_node_t *)H5AC_protect(f, dxpl_id, H5AC_SNODE, addr, f, H5AC_READ)))
+    if(NULL == (sn = (H5G_node_t *)H5AC_protect(f, dxpl_id, H5AC_SNODE, addr, f, H5AC__READ_ONLY_FLAG)))
 	HGOTO_ERROR(H5E_SYM, H5E_CANTLOAD, H5_ITER_ERROR, "unable to load symbol table node")
 
     /*
@@ -1078,7 +1078,7 @@ H5G__node_sumup(H5F_t *f, hid_t dxpl_id, const void H5_ATTR_UNUSED *_lt_key, had
     HDassert(num_objs);
 
     /* Find the object node and add the number of symbol entries. */
-    if(NULL == (sn = (H5G_node_t *)H5AC_protect(f, dxpl_id, H5AC_SNODE, addr, f, H5AC_READ)))
+    if(NULL == (sn = (H5G_node_t *)H5AC_protect(f, dxpl_id, H5AC_SNODE, addr, f, H5AC__READ_ONLY_FLAG)))
 	HGOTO_ERROR(H5E_SYM, H5E_CANTLOAD, H5_ITER_ERROR, "unable to load symbol table node")
 
     *num_objs += sn->nsyms;
@@ -1123,7 +1123,7 @@ H5G__node_by_idx(H5F_t *f, hid_t dxpl_id, const void H5_ATTR_UNUSED *_lt_key, ha
     HDassert(udata);
 
     /* Get a pointer to the symbol table node */
-    if(NULL == (sn = (H5G_node_t *)H5AC_protect(f, dxpl_id, H5AC_SNODE, addr, f, H5AC_READ)))
+    if(NULL == (sn = (H5G_node_t *)H5AC_protect(f, dxpl_id, H5AC_SNODE, addr, f, H5AC__READ_ONLY_FLAG)))
 	HGOTO_ERROR(H5E_SYM, H5E_CANTLOAD, H5_ITER_ERROR, "unable to load symbol table node");
 
     /* Find the node, locate the object symbol table entry and retrieve the name */
@@ -1261,11 +1261,11 @@ H5G__node_copy(H5F_t *f, hid_t dxpl_id, const void H5_ATTR_UNUSED *_lt_key, hadd
     HDassert(udata);
 
     /* load the symbol table into memory from the source file */
-    if(NULL == (sn = (H5G_node_t *)H5AC_protect(f, dxpl_id, H5AC_SNODE, addr, f, H5AC_READ)))
+    if(NULL == (sn = (H5G_node_t *)H5AC_protect(f, dxpl_id, H5AC_SNODE, addr, f, H5AC__READ_ONLY_FLAG)))
 	HGOTO_ERROR(H5E_SYM, H5E_CANTLOAD, H5_ITER_ERROR, "unable to load symbol table node")
 
     /* get the base address of the heap */
-    if(NULL == (heap = H5HL_protect(f, dxpl_id, udata->src_heap_addr, H5AC_READ)))
+    if(NULL == (heap = H5HL_protect(f, dxpl_id, udata->src_heap_addr, H5AC__READ_ONLY_FLAG)))
        HGOTO_ERROR(H5E_SYM, H5E_NOTFOUND, H5_ITER_ERROR, "unable to protect symbol name")
 
     /* copy object in this node one by one */
@@ -1420,7 +1420,7 @@ H5G__node_build_table(H5F_t *f, hid_t dxpl_id, const void H5_ATTR_UNUSED *_lt_ke
      * Save information about the symbol table node since we can't lock it
      * because we're about to call an application function.
      */
-    if(NULL == (sn = (H5G_node_t *)H5AC_protect(f, dxpl_id, H5AC_SNODE, addr, f, H5AC_READ)))
+    if(NULL == (sn = (H5G_node_t *)H5AC_protect(f, dxpl_id, H5AC_SNODE, addr, f, H5AC__READ_ONLY_FLAG)))
 	HGOTO_ERROR(H5E_SYM, H5E_CANTLOAD, H5_ITER_ERROR, "unable to load symbol table node")
 
     /* Check if the link table needs to be extended */
@@ -1527,14 +1527,14 @@ H5G_node_debug(H5F_t *f, hid_t dxpl_id, haddr_t addr, FILE * stream, int indent,
 
     /* Pin the heap down in memory */
     if(heap_addr > 0 && H5F_addr_defined(heap_addr))
-        if(NULL == (heap = H5HL_protect(f, dxpl_id, heap_addr, H5AC_READ)))
+        if(NULL == (heap = H5HL_protect(f, dxpl_id, heap_addr, H5AC__READ_ONLY_FLAG)))
             HGOTO_ERROR(H5E_SYM, H5E_CANTLOAD, FAIL, "unable to protect symbol table heap")
 
     /*
      * If we couldn't load the symbol table node, then try loading the
      * B-tree node.
      */
-    if(NULL == (sn = (H5G_node_t *)H5AC_protect(f, dxpl_id, H5AC_SNODE, addr, f, H5AC_READ))) {
+    if(NULL == (sn = (H5G_node_t *)H5AC_protect(f, dxpl_id, H5AC_SNODE, addr, f, H5AC__READ_ONLY_FLAG))) {
         H5G_bt_common_t	udata;		/*data to pass through B-tree	*/
 
         H5E_clear_stack(NULL); /* discard that error */
diff --git a/src/H5Gstab.c b/src/H5Gstab.c
index 4c338c9..08188ae 100644
--- a/src/H5Gstab.c
+++ b/src/H5Gstab.c
@@ -160,7 +160,7 @@ H5G__stab_create_components(H5F_t *f, H5O_stab_t *stab, size_t size_hint, hid_t
 	HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "can't create heap")
 
     /* Pin the heap down in memory */
-    if(NULL == (heap = H5HL_protect(f, dxpl_id, stab->heap_addr, H5AC_WRITE)))
+    if(NULL == (heap = H5HL_protect(f, dxpl_id, stab->heap_addr, H5AC__NO_FLAGS_SET)))
         HGOTO_ERROR(H5E_SYM, H5E_PROTECT, FAIL, "unable to protect symbol table heap")
 
     /* Insert name into the heap */
@@ -276,7 +276,7 @@ H5G__stab_insert_real(H5F_t *f, const H5O_stab_t *stab, const char *name,
     HDassert(obj_lnk);
 
     /* Pin the heap down in memory */
-    if(NULL == (heap = H5HL_protect(f, dxpl_id, stab->heap_addr, H5AC_WRITE)))
+    if(NULL == (heap = H5HL_protect(f, dxpl_id, stab->heap_addr, H5AC__NO_FLAGS_SET)))
         HGOTO_ERROR(H5E_SYM, H5E_PROTECT, FAIL, "unable to protect symbol table heap")
 
     /* Initialize data to pass through B-tree */
@@ -373,7 +373,7 @@ H5G__stab_remove(const H5O_loc_t *loc, hid_t dxpl_id, H5RS_str_t *grp_full_path_
         HGOTO_ERROR(H5E_SYM, H5E_BADMESG, FAIL, "not a symbol table")
 
     /* Pin the heap down in memory */
-    if(NULL == (heap = H5HL_protect(loc->file, dxpl_id, stab.heap_addr, H5AC_WRITE)))
+    if(NULL == (heap = H5HL_protect(loc->file, dxpl_id, stab.heap_addr, H5AC__NO_FLAGS_SET)))
         HGOTO_ERROR(H5E_SYM, H5E_PROTECT, FAIL, "unable to protect symbol table heap")
 
     /* Initialize data to pass through B-tree */
@@ -431,7 +431,7 @@ H5G__stab_remove_by_idx(const H5O_loc_t *grp_oloc, hid_t dxpl_id, H5RS_str_t *gr
         HGOTO_ERROR(H5E_SYM, H5E_BADMESG, FAIL, "not a symbol table")
 
     /* Pin the heap down in memory */
-    if(NULL == (heap = H5HL_protect(grp_oloc->file, dxpl_id, stab.heap_addr, H5AC_WRITE)))
+    if(NULL == (heap = H5HL_protect(grp_oloc->file, dxpl_id, stab.heap_addr, H5AC__NO_FLAGS_SET)))
         HGOTO_ERROR(H5E_SYM, H5E_PROTECT, FAIL, "unable to protect symbol table heap")
 
     /* Initialize data to pass through B-tree */
@@ -485,7 +485,7 @@ H5G__stab_delete(H5F_t *f, hid_t dxpl_id, const H5O_stab_t *stab)
     HDassert(H5F_addr_defined(stab->heap_addr));
 
     /* Pin the heap down in memory */
-    if(NULL == (heap = H5HL_protect(f, dxpl_id, stab->heap_addr, H5AC_WRITE)))
+    if(NULL == (heap = H5HL_protect(f, dxpl_id, stab->heap_addr, H5AC__NO_FLAGS_SET)))
         HGOTO_ERROR(H5E_SYM, H5E_PROTECT, FAIL, "unable to protect symbol table heap")
 
     /* Set up user data for B-tree deletion */
@@ -546,7 +546,7 @@ H5G__stab_iterate(const H5O_loc_t *oloc, hid_t dxpl_id, H5_iter_order_t order,
 	HGOTO_ERROR(H5E_SYM, H5E_NOTFOUND, FAIL, "unable to determine local heap address")
 
     /* Pin the heap down in memory */
-    if(NULL == (heap = H5HL_protect(oloc->file, dxpl_id, stab.heap_addr, H5AC_READ)))
+    if(NULL == (heap = H5HL_protect(oloc->file, dxpl_id, stab.heap_addr, H5AC__READ_ONLY_FLAG)))
         HGOTO_ERROR(H5E_SYM, H5E_PROTECT, FAIL, "unable to protect symbol table heap")
 
     /* Check on iteration order */
@@ -766,7 +766,7 @@ H5G__stab_get_name_by_idx(const H5O_loc_t *oloc, H5_iter_order_t order, hsize_t
 	HGOTO_ERROR(H5E_SYM, H5E_NOTFOUND, FAIL, "unable to determine local heap address")
 
     /* Pin the heap down in memory */
-    if(NULL == (heap = H5HL_protect(oloc->file, dxpl_id, stab.heap_addr, H5AC_READ)))
+    if(NULL == (heap = H5HL_protect(oloc->file, dxpl_id, stab.heap_addr, H5AC__READ_ONLY_FLAG)))
         HGOTO_ERROR(H5E_SYM, H5E_PROTECT, FAIL, "unable to protect symbol table heap")
 
     /* Remap index for decreasing iteration order */
@@ -888,7 +888,7 @@ H5G__stab_lookup(const H5O_loc_t *grp_oloc, const char *name, H5O_link_t *lnk,
         HGOTO_ERROR(H5E_SYM, H5E_BADMESG, FAIL, "can't read message")
 
     /* Pin the heap down in memory */
-    if(NULL == (heap = H5HL_protect(grp_oloc->file, dxpl_id, stab.heap_addr, H5AC_READ)))
+    if(NULL == (heap = H5HL_protect(grp_oloc->file, dxpl_id, stab.heap_addr, H5AC__READ_ONLY_FLAG)))
         HGOTO_ERROR(H5E_SYM, H5E_PROTECT, FAIL, "unable to protect symbol table heap")
 
     /* Set up user data to pass to 'find' operation callback */
@@ -989,7 +989,7 @@ H5G__stab_lookup_by_idx(const H5O_loc_t *grp_oloc, H5_iter_order_t order, hsize_
 	HGOTO_ERROR(H5E_SYM, H5E_NOTFOUND, FAIL, "unable to determine local heap address")
 
     /* Pin the heap down in memory */
-    if(NULL == (heap = H5HL_protect(grp_oloc->file, dxpl_id, stab.heap_addr, H5AC_READ)))
+    if(NULL == (heap = H5HL_protect(grp_oloc->file, dxpl_id, stab.heap_addr, H5AC__READ_ONLY_FLAG)))
         HGOTO_ERROR(H5E_SYM, H5E_PROTECT, FAIL, "unable to protect symbol table heap")
 
     /* Remap index for decreasing iteration order */
@@ -1081,10 +1081,10 @@ H5G__stab_valid(H5O_loc_t *grp_oloc, hid_t dxpl_id, H5O_stab_t *alt_stab)
     } /* end if */
 
     /* Check if the symbol table message's heap address is valid */
-    if(NULL == (heap = H5HL_protect(grp_oloc->file, dxpl_id, stab.heap_addr, H5AC_READ))) {
+    if(NULL == (heap = H5HL_protect(grp_oloc->file, dxpl_id, stab.heap_addr, H5AC__READ_ONLY_FLAG))) {
         /* Address is invalid, try the heap address in the alternate symbol
          * table message */
-        if(!alt_stab || NULL == (heap = H5HL_protect(grp_oloc->file, dxpl_id, alt_stab->heap_addr, H5AC_READ)))
+        if(!alt_stab || NULL == (heap = H5HL_protect(grp_oloc->file, dxpl_id, alt_stab->heap_addr, H5AC__READ_ONLY_FLAG)))
             HGOTO_ERROR(H5E_HEAP, H5E_NOTFOUND, FAIL, "unable to locate heap")
         else {
             /* The alternate symbol table's heap address is valid.  Adjust the
diff --git a/src/H5Gtest.c b/src/H5Gtest.c
index 89b4a37..1c0adea 100644
--- a/src/H5Gtest.c
+++ b/src/H5Gtest.c
@@ -637,7 +637,7 @@ H5G__verify_cached_stab_test(H5O_loc_t *grp_oloc, H5G_entry_t *ent)
         HGOTO_ERROR(H5E_BTREE, H5E_NOTFOUND, FAIL, "b-tree address is invalid")
 
     /* Verify that the heap address is valid */
-    if(NULL == (heap = H5HL_protect(grp_oloc->file, dxpl_id, stab.heap_addr, H5AC_READ)))
+    if(NULL == (heap = H5HL_protect(grp_oloc->file, dxpl_id, stab.heap_addr, H5AC__READ_ONLY_FLAG)))
         HGOTO_ERROR(H5E_HEAP, H5E_NOTFOUND, FAIL, "heap address is invalid")
 
 done:
@@ -686,7 +686,7 @@ H5G_verify_cached_stabs_test_cb(H5F_t *f, hid_t dxpl_id,
     HDassert(H5F_addr_defined(addr));
 
     /* Load the node */
-    if(NULL == (sn = (H5G_node_t *)H5AC_protect(f, dxpl_id, H5AC_SNODE, addr, f, H5AC_READ)))
+    if(NULL == (sn = (H5G_node_t *)H5AC_protect(f, dxpl_id, H5AC_SNODE, addr, f, H5AC__READ_ONLY_FLAG)))
         HGOTO_ERROR(H5E_SYM, H5E_CANTLOAD, H5_ITER_ERROR, "unable to load symbol table node")
 
     /* Check each target object to see if its stab message (if present) matches
@@ -701,7 +701,7 @@ H5G_verify_cached_stabs_test_cb(H5F_t *f, hid_t dxpl_id,
         targ_oloc.addr = sn->entry[i].header;
 
         /* Load target object header */
-        if(NULL == (targ_oh = H5O_protect(&targ_oloc, dxpl_id, H5AC_READ)))
+        if(NULL == (targ_oh = H5O_protect(&targ_oloc, dxpl_id, H5AC__READ_ONLY_FLAG)))
             HGOTO_ERROR(H5E_SYM, H5E_CANTPROTECT, H5_ITER_ERROR, "unable to protect target object header")
 
         /* Check if a symbol table message exists */
diff --git a/src/H5HF.c b/src/H5HF.c
index f57c5e2..0464da4 100644
--- a/src/H5HF.c
+++ b/src/H5HF.c
@@ -172,7 +172,7 @@ H5HF_create(H5F_t *f, hid_t dxpl_id, const H5HF_create_t *cparam)
         HGOTO_ERROR(H5E_HEAP, H5E_CANTALLOC, NULL, "memory allocation failed for fractal heap info")
 
     /* Lock the heap header into memory */
-    if(NULL == (hdr = H5HF_hdr_protect(f, dxpl_id, fh_addr, H5AC_WRITE)))
+    if(NULL == (hdr = H5HF_hdr_protect(f, dxpl_id, fh_addr, H5AC__NO_FLAGS_SET)))
         HGOTO_ERROR(H5E_HEAP, H5E_CANTPROTECT, NULL, "unable to protect fractal heap header")
 
     /* Point fractal heap wrapper at header and bump it's ref count */
@@ -231,7 +231,7 @@ H5HF_open(H5F_t *f, hid_t dxpl_id, haddr_t fh_addr)
     HDassert(H5F_addr_defined(fh_addr));
 
     /* Load the heap header into memory */
-    if(NULL == (hdr = H5HF_hdr_protect(f, dxpl_id, fh_addr, H5AC_READ)))
+    if(NULL == (hdr = H5HF_hdr_protect(f, dxpl_id, fh_addr, H5AC__READ_ONLY_FLAG)))
         HGOTO_ERROR(H5E_HEAP, H5E_CANTPROTECT, NULL, "unable to protect fractal heap header")
 
     /* Check for pending heap deletion */
@@ -821,7 +821,7 @@ H5HF_close(H5HF_t *fh, hid_t dxpl_id)
         H5HF_hdr_t *hdr;            /* Another pointer to fractal heap header */
 
         /* Lock the heap header into memory */
-        if(NULL == (hdr = H5HF_hdr_protect(fh->f, dxpl_id, heap_addr, H5AC_WRITE)))
+        if(NULL == (hdr = H5HF_hdr_protect(fh->f, dxpl_id, heap_addr, H5AC__NO_FLAGS_SET)))
             HGOTO_ERROR(H5E_HEAP, H5E_CANTPROTECT, FAIL, "unable to protect fractal heap header")
 
         /* Delete heap, starting with header (unprotects header) */
@@ -865,7 +865,7 @@ H5HF_delete(H5F_t *f, hid_t dxpl_id, haddr_t fh_addr)
     HDassert(H5F_addr_defined(fh_addr));
 
     /* Lock the heap header into memory */
-    if(NULL == (hdr = H5HF_hdr_protect(f, dxpl_id, fh_addr, H5AC_WRITE)))
+    if(NULL == (hdr = H5HF_hdr_protect(f, dxpl_id, fh_addr, H5AC__NO_FLAGS_SET)))
         HGOTO_ERROR(H5E_HEAP, H5E_CANTPROTECT, FAIL, "unable to protect fractal heap header")
 
     /* Check for files using shared heap header */
diff --git a/src/H5HFcache.c b/src/H5HFcache.c
index 07e5b36..ec8d9a6 100644
--- a/src/H5HFcache.c
+++ b/src/H5HFcache.c
@@ -53,12 +53,6 @@
 #define H5HF_DBLOCK_VERSION     0               /* Direct block */
 #define H5HF_IBLOCK_VERSION     0               /* Indirect block */
 
-/* Size of stack buffer for serialized headers */
-#define H5HF_HDR_BUF_SIZE       512
-
-/* Size of stack buffer for serialized indirect blocks */
-#define H5HF_IBLOCK_BUF_SIZE    4096
-
 
 /******************/
 /* Local Typedefs */
@@ -79,24 +73,48 @@ static herr_t H5HF__dtable_encode(H5F_t *f, uint8_t **pp, const H5HF_dtable_t *d
 static herr_t H5HF__dtable_decode(H5F_t *f, const uint8_t **pp, H5HF_dtable_t *dtable);
 
 /* Metadata cache (H5AC) callbacks */
-static H5HF_hdr_t *H5HF_cache_hdr_load(H5F_t *f, hid_t dxpl_id, haddr_t addr, void *udata);
-static herr_t H5HF_cache_hdr_flush(H5F_t *f, hid_t dxpl_id, hbool_t destroy, haddr_t addr, H5HF_hdr_t *hdr, unsigned H5_ATTR_UNUSED * flags_ptr);
-static herr_t H5HF_cache_hdr_dest(H5F_t *f, H5HF_hdr_t *hdr);
-static herr_t H5HF_cache_hdr_clear(H5F_t *f, H5HF_hdr_t *hdr, hbool_t destroy);
-static herr_t H5HF_cache_hdr_size(const H5F_t *f, const H5HF_hdr_t *hdr, size_t *size_ptr);
-static H5HF_indirect_t *H5HF_cache_iblock_load(H5F_t *f, hid_t dxpl_id, haddr_t addr, void *udata);
-static herr_t H5HF_cache_iblock_flush(H5F_t *f, hid_t dxpl_id, hbool_t destroy, haddr_t addr, H5HF_indirect_t *iblock, unsigned H5_ATTR_UNUSED * flags_ptr);
-static herr_t H5HF_cache_iblock_dest(H5F_t *f, H5HF_indirect_t *iblock);
-static herr_t H5HF_cache_iblock_clear(H5F_t *f, H5HF_indirect_t *iblock, hbool_t destroy);
-static herr_t H5HF_cache_iblock_notify(H5C_notify_action_t action, H5HF_indirect_t *iblock);
-static herr_t H5HF_cache_iblock_size(const H5F_t *f, const H5HF_indirect_t *iblock, size_t *size_ptr);
-static H5HF_direct_t *H5HF_cache_dblock_load(H5F_t *f, hid_t dxpl_id, haddr_t addr, void *udata);
-static herr_t H5HF_cache_dblock_flush(H5F_t *f, hid_t dxpl_id, hbool_t destroy, haddr_t addr, H5HF_direct_t *dblock, unsigned H5_ATTR_UNUSED * flags_ptr);
-static herr_t H5HF_cache_dblock_dest(H5F_t *f, H5HF_direct_t *dblock);
-static herr_t H5HF_cache_dblock_clear(H5F_t *f, H5HF_direct_t *dblock, hbool_t destroy);
-static herr_t H5HF_cache_dblock_notify(H5C_notify_action_t action, H5HF_direct_t *dblock);
-static herr_t H5HF_cache_dblock_size(const H5F_t *f, const H5HF_direct_t *dblock, size_t *size_ptr);
-
+static herr_t H5HF__cache_hdr_get_load_size(const void *udata, size_t *image_len);
+static void *H5HF__cache_hdr_deserialize(const void *image, size_t len,
+    void *udata, hbool_t *dirty); 
+static herr_t H5HF__cache_hdr_image_len(const void *thing, size_t *image_len,
+    hbool_t *compressed_ptr, size_t *compressed_image_len_ptr);
+static herr_t H5HF__cache_hdr_pre_serialize(const H5F_t *f, hid_t dxpl_id,
+    void *thing, haddr_t addr, size_t len, size_t compressed_len, 
+    haddr_t *new_addr, size_t *new_len, size_t *new_compressed_len, 
+    unsigned *flags); 
+static herr_t H5HF__cache_hdr_serialize(const H5F_t *f, void *image,
+    size_t len, void *thing); 
+static herr_t H5HF__cache_hdr_free_icr(void *thing);
+
+static herr_t H5HF__cache_iblock_get_load_size(const void *udata, size_t *image_len);
+static void *H5HF__cache_iblock_deserialize(const void *image, size_t len,
+    void *udata, hbool_t *dirty); 
+static herr_t H5HF__cache_iblock_image_len(const void *thing, 
+    size_t *image_len, hbool_t *compressed_ptr, 
+    size_t *compressed_image_len_ptr);
+static herr_t H5HF__cache_iblock_pre_serialize(const H5F_t *f, hid_t dxpl_id,
+    void *thing, haddr_t addr, size_t len, size_t compressed_len, 
+    haddr_t *new_addr, size_t *new_len, size_t *new_compressed_len, 
+    unsigned *flags); 
+static herr_t H5HF__cache_iblock_serialize(const H5F_t *f, void *image,
+    size_t len, void *thing); 
+static herr_t H5HF__cache_iblock_notify(H5C_notify_action_t action, void *thing); 
+static herr_t H5HF__cache_iblock_free_icr(void *thing);
+
+static herr_t H5HF__cache_dblock_get_load_size(const void *udata, size_t *image_len);
+static void *H5HF__cache_dblock_deserialize(const void *image, size_t len,
+    void *udata, hbool_t *dirty); 
+static herr_t H5HF__cache_dblock_image_len(const void *thing, 
+    size_t *image_len, hbool_t *compressed_ptr, 
+    size_t *compressed_image_len_ptr);
+static herr_t H5HF__cache_dblock_pre_serialize(const H5F_t *f, hid_t dxpl_id,
+    void *thing, haddr_t addr, size_t len, size_t compressed_len,
+    haddr_t *new_addr, size_t *new_len, size_t *new_compressed_len, 
+    unsigned *flags); 
+static herr_t H5HF__cache_dblock_serialize(const H5F_t *f, void *image,
+    size_t len, void *thing); 
+static herr_t H5HF__cache_dblock_notify(H5C_notify_action_t action, void *thing);
+static herr_t H5HF__cache_dblock_free_icr(void *thing);
 
 /* Debugging Function Prototypes */
 #ifndef NDEBUG
@@ -117,35 +135,53 @@ static herr_t H5HF__cache_verify_descendant_iblocks_clean(H5F_t *f, hid_t dxpl_i
 
 /* H5HF header inherits cache-like properties from H5AC */
 const H5AC_class_t H5AC_FHEAP_HDR[1] = {{
-    H5AC_FHEAP_HDR_ID,
-    (H5AC_load_func_t)H5HF_cache_hdr_load,
-    (H5AC_flush_func_t)H5HF_cache_hdr_flush,
-    (H5AC_dest_func_t)H5HF_cache_hdr_dest,
-    (H5AC_clear_func_t)H5HF_cache_hdr_clear,
-    (H5AC_notify_func_t)NULL,
-    (H5AC_size_func_t)H5HF_cache_hdr_size,
+    H5AC_FHEAP_HDR_ID,                  /* Metadata client ID */
+    "fractal heap header",              /* Metadata client name (for debugging) */
+    H5FD_MEM_FHEAP_HDR,                 /* File space memory type for client */
+    H5AC__CLASS_SPECULATIVE_LOAD_FLAG,  /* Client class behavior flags */
+    H5HF__cache_hdr_get_load_size,      /* 'get_load_size' callback */
+    H5HF__cache_hdr_deserialize,        /* 'deserialize' callback */
+    H5HF__cache_hdr_image_len,          /* 'image_len' callback */
+    H5HF__cache_hdr_pre_serialize,      /* 'pre_serialize' callback */
+    H5HF__cache_hdr_serialize,          /* 'serialize' callback */
+    NULL,                               /* 'notify' callback */
+    H5HF__cache_hdr_free_icr,           /* 'free_icr' callback */
+    NULL,                               /* 'clear' callback */
+    NULL,                               /* 'fsf_size' callback */
 }};
 
 /* H5HF indirect block inherits cache-like properties from H5AC */
 const H5AC_class_t H5AC_FHEAP_IBLOCK[1] = {{
-    H5AC_FHEAP_IBLOCK_ID,
-    (H5AC_load_func_t)H5HF_cache_iblock_load,
-    (H5AC_flush_func_t)H5HF_cache_iblock_flush,
-    (H5AC_dest_func_t)H5HF_cache_iblock_dest,
-    (H5AC_clear_func_t)H5HF_cache_iblock_clear,
-    (H5AC_notify_func_t)H5HF_cache_iblock_notify,
-    (H5AC_size_func_t)H5HF_cache_iblock_size,
+    H5AC_FHEAP_IBLOCK_ID,               /* Metadata client ID */
+    "fractal heap indirect block",      /* Metadata client name (for debugging) */
+    H5FD_MEM_FHEAP_IBLOCK,              /* File space memory type for client */
+    H5AC__CLASS_NO_FLAGS_SET,           /* Client class behavior flags */
+    H5HF__cache_iblock_get_load_size,   /* 'get_load_size' callback */
+    H5HF__cache_iblock_deserialize,     /* 'deserialize' callback */
+    H5HF__cache_iblock_image_len,       /* 'image_len' callback */
+    H5HF__cache_iblock_pre_serialize,   /* 'pre_serialize' callback */
+    H5HF__cache_iblock_serialize,       /* 'serialize' callback */
+    H5HF__cache_iblock_notify,          /* 'notify' callback */
+    H5HF__cache_iblock_free_icr,        /* 'free_icr' callback */
+    NULL,                               /* 'clear' callback */
+    NULL,                               /* 'fsf_size' callback */
 }};
 
 /* H5HF direct block inherits cache-like properties from H5AC */
 const H5AC_class_t H5AC_FHEAP_DBLOCK[1] = {{
-    H5AC_FHEAP_DBLOCK_ID,
-    (H5AC_load_func_t)H5HF_cache_dblock_load,
-    (H5AC_flush_func_t)H5HF_cache_dblock_flush,
-    (H5AC_dest_func_t)H5HF_cache_dblock_dest,
-    (H5AC_clear_func_t)H5HF_cache_dblock_clear,
-    (H5AC_notify_func_t)H5HF_cache_dblock_notify,
-    (H5AC_size_func_t)H5HF_cache_dblock_size,
+    H5AC_FHEAP_DBLOCK_ID,               /* Metadata client ID */
+    "fractal heap direct block",        /* Metadata client name (for debugging) */
+    H5FD_MEM_FHEAP_DBLOCK,              /* File space memory type for client */
+    H5C__CLASS_COMPRESSED_FLAG,         /* Client class behavior flags */
+    H5HF__cache_dblock_get_load_size,   /* 'get_load_size' callback */
+    H5HF__cache_dblock_deserialize,     /* 'deserialize' callback */
+    H5HF__cache_dblock_image_len,       /* 'image_len' callback */
+    H5HF__cache_dblock_pre_serialize,   /* 'pre_serialize' callback */
+    H5HF__cache_dblock_serialize,       /* 'serialize' callback */
+    H5HF__cache_dblock_notify,          /* 'notify' callback */
+    H5HF__cache_dblock_free_icr,        /* 'free_icr' callback */
+    NULL,                               /* 'clear' callback */
+    NULL,                               /* 'fsf_size' callback */
 }};
 
 
@@ -268,119 +304,191 @@ H5HF__dtable_encode(H5F_t *f, uint8_t **pp, const H5HF_dtable_t *dtable)
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5HF_cache_hdr_load
+ * Function:	H5HF__cache_hdr_get_load_size()
  *
- * Purpose:	Loads a fractal heap header from the disk.
+ * Purpose:	Determine the size of the fractal heap header on disk,
+ *		and set *image_len to this value.
  *
- * Return:	Success:	Pointer to a new fractal heap
+ *		This code is based on the old H5HF_cache_hdr_load() routine
+ *		that was used with the version 2 metadata cache.  Note the 
+ *		use of a dummy header to compute the on disk size of the header.
+ *
+ *		Note also that the value returned by this function presumes that 
+ *		there is no I/O filtering data in the header.  If there is, the 
+ *		size reported will be too small, and H5C_load_entry()
+ *		will have to make two tries to load the fractal heap header.
+ *
+ * Return:	Success:	SUCCEED
+ *		Failure:	FAIL
+ *
+ * Programmer:	John Mainzer
+ *		6/21/14
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t 
+H5HF__cache_hdr_get_load_size(const void *_udata, size_t *image_len)
+{
+    const H5HF_hdr_cache_ud_t *udata = (const H5HF_hdr_cache_ud_t *)_udata; /* pointer to user data */
+    H5HF_hdr_t  	dummy_hdr; 	/* dummy header -- to compute size */
+
+    FUNC_ENTER_STATIC_NOERR
+
+    /* Sanity checks */
+    HDassert(udata);
+    HDassert(image_len);
+
+    /* Set the internal parameters for the heap */
+    dummy_hdr.f = udata->f;
+    dummy_hdr.sizeof_size = H5F_SIZEOF_SIZE(udata->f);
+    dummy_hdr.sizeof_addr = H5F_SIZEOF_ADDR(udata->f);
+
+    /* Compute the 'base' size of the fractal heap header on disk */
+    *image_len = (size_t)H5HF_HEADER_SIZE(&dummy_hdr);
+
+    FUNC_LEAVE_NOAPI(SUCCEED)
+} /* end H5HF__cache_hdr_get_load_size() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:	H5HF__cache_hdr_deserialize
+ *
+ * Purpose:	Given a buffer containing an on disk image of a fractal heap
+ *		header block, allocate an instance of H5HF_hdr_t, load the contents
+ *		of the buffer into into the new instance of H5HF_hdr_t, and then
+ *		return a pointer to the new instance.
+ *
+ *		Since H5HF__cache_hdr_get_load_size() reports header on disk size 
+ *		base on the assumption that the header contains no I/O filtering 
+ *		data, it is possible that the provided image will be too small.
+ *
+ *		In this case, we DO NOT flag an error when this is discovered.
+ *		Instead, we make note of the correct image size, and report 
+ *		success.
+ *
+ *		Since H5HF__cache_hdr_image_len() callback is defined, 
+ *		H5C_load_entry() will call H5HF__cache_hdr_image_len() and 
+ *		obtain the correct image length.  
+ *
+ *		Since the H5AC__CLASS_SPECULATIVE_LOAD_FLAG is set, 
+ *		H5C_load_entry() will load an image of the correct size, and 
+ *		then call this function again to deserialize it.  Before doing 
+ *		so, it will also call H5HF__cache_hdr_free_icr() to discard the 
+ *		result of the first deserialize call.
+ *
+ *		Note that the v2 B-tree and free space manager associated 
+ *		with the fractal heap (roots stored in the huge_bt2 and fspace 
+ *		fields respectively) are not loaded at this time.  As best I can
+ *		tell from reviewing the code, they are loaded or created when 
+ *		they are accessed.
+ *
+ * Return:	Success:	Pointer to in core representation
  *		Failure:	NULL
  *
- * Programmer:	Quincey Koziol
- *		koziol@ncsa.uiuc.edu
- *		Feb 24 2006
+ * Programmer:	John Mainzer
+ *		6/21/14
  *
  *-------------------------------------------------------------------------
  */
-static H5HF_hdr_t *
-H5HF_cache_hdr_load(H5F_t *f, hid_t dxpl_id, haddr_t addr, void *_udata)
+static void *
+H5HF__cache_hdr_deserialize(const void *_image, size_t len, void *_udata,
+    hbool_t H5_ATTR_UNUSED *dirty)
 {
-    H5HF_hdr_t		*hdr = NULL;     /* Fractal heap info */
-    H5HF_hdr_cache_ud_t *udata = (H5HF_hdr_cache_ud_t *)_udata;
-    size_t		size;           /* Header size */
-    H5WB_t              *wb = NULL;     /* Wrapped buffer for header data */
-    uint8_t             hdr_buf[H5HF_HDR_BUF_SIZE]; /* Buffer for header */
-    uint8_t		*buf;           /* Pointer to header buffer */
-    const uint8_t	*p;             /* Pointer into raw data buffer */
+    H5HF_hdr_t          *hdr = NULL;     /* Fractal heap info */
+    H5HF_hdr_cache_ud_t *udata = (H5HF_hdr_cache_ud_t *)_udata; /* User data for callback */
+    const uint8_t       *image = (const uint8_t *)_image;       /* Pointer into into supplied image */
+    size_t              size;           /* Header size */
     uint32_t            stored_chksum;  /* Stored metadata checksum value */
     uint32_t            computed_chksum; /* Computed metadata checksum value */
     uint8_t             heap_flags;     /* Status flags for heap */
-    H5HF_hdr_t		*ret_value;     /* Return value */
+    void *              ret_value;      /* Return value */
 
-    FUNC_ENTER_NOAPI_NOINIT
+    FUNC_ENTER_STATIC
 
-    /* Check arguments */
-    HDassert(f);
-    HDassert(H5F_addr_defined(addr));
+    /* Sanity checks */
+    HDassert(image);
+    HDassert(len > 0);
     HDassert(udata);
+    HDassert(dirty);
 
     /* Allocate space for the fractal heap data structure */
     if(NULL == (hdr = H5HF_hdr_alloc(udata->f)))
         HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, NULL, "memory allocation failed")
 
-    /* Wrap the local buffer for serialized header info */
-    if(NULL == (wb = H5WB_wrap(hdr_buf, sizeof(hdr_buf))))
-        HGOTO_ERROR(H5E_HEAP, H5E_CANTINIT, NULL, "can't wrap buffer")
-
     /* Compute the 'base' size of the fractal heap header on disk */
     size = (size_t)H5HF_HEADER_SIZE(hdr);
 
-    /* Get a pointer to a buffer that's large enough for serialized header */
-    if(NULL == (buf = (uint8_t *)H5WB_actual(wb, size)))
-        HGOTO_ERROR(H5E_HEAP, H5E_NOSPACE, NULL, "can't get actual buffer")
-
-    /* Read header from disk */
-    if(H5F_block_read(f, H5FD_MEM_FHEAP_HDR, addr, size, dxpl_id, buf) < 0)
-	HGOTO_ERROR(H5E_HEAP, H5E_READERROR, NULL, "can't read fractal heap header")
-
-    /* Get temporary pointer to serialized header */
-    p = buf;
+    /* the size we have just calculated presumes that there is no I/O 
+     * filter information in the header.  If there is no filter information,
+     * the deserialize operation should succeed.
+     *
+     * If there is filter information, the first attempt to deserialize 
+     * the header will reveal this.  In this case, we will be unable to 
+     * deserialize the header as the supplied image will be too small.
+     * However, we will make note of the correct size and report success 
+     * anyway.  
+     *
+     * When H5C_load_entry() calls H5HF__cache_hdr_image_len(), we will report 
+     * the correct size.  Since the H5C__CLASS_SPECULATIVE_LOAD_FLAG is set,
+     * this will prompt H5C_load_entry() to load the correct size image,
+     * discard the result of the first attempt at deserialization, and 
+     * call this routine a second time to deserialize the correct size 
+     * buffer.
+     */
+    HDassert(size <= len);
 
     /* Magic number */
-    if(HDmemcmp(p, H5HF_HDR_MAGIC, (size_t)H5_SIZEOF_MAGIC))
-        HGOTO_ERROR(H5E_HEAP, H5E_CANTLOAD, NULL, "wrong fractal heap header signature")
-    p += H5_SIZEOF_MAGIC;
+    if(HDmemcmp(image, H5HF_HDR_MAGIC, (size_t)H5_SIZEOF_MAGIC))
+        HGOTO_ERROR(H5E_HEAP, H5E_BADVALUE, NULL, "wrong fractal heap header signature")
+    image += H5_SIZEOF_MAGIC;
 
     /* Version */
-    if(*p++ != H5HF_HDR_VERSION)
+    if(*image++ != H5HF_HDR_VERSION)
         HGOTO_ERROR(H5E_HEAP, H5E_VERSION, NULL, "wrong fractal heap header version")
 
     /* General heap information */
-    UINT16DECODE(p, hdr->id_len);               /* Heap ID length */
-    UINT16DECODE(p, hdr->filter_len);           /* I/O filters' encoded length */
+    UINT16DECODE(image, hdr->id_len);              /* Heap ID length */
+    UINT16DECODE(image, hdr->filter_len);          /* I/O filters' encoded length */
 
     /* Heap status flags */
     /* (bit 0: "huge" object IDs have wrapped) */
     /* (bit 1: checksum direct blocks) */
-    heap_flags = *p++;
+    heap_flags = *image++;
     hdr->huge_ids_wrapped = heap_flags & H5HF_HDR_FLAGS_HUGE_ID_WRAPPED;
     hdr->checksum_dblocks = heap_flags & H5HF_HDR_FLAGS_CHECKSUM_DBLOCKS;
 
     /* "Huge" object information */
-    UINT32DECODE(p, hdr->max_man_size);         /* Max. size of "managed" objects */
-    H5F_DECODE_LENGTH(udata->f, p, hdr->huge_next_id); /* Next ID to use for "huge" object */
-    H5F_addr_decode(udata->f, &p, &hdr->huge_bt2_addr); /* Address of "huge" object tracker B-tree */
+    UINT32DECODE(image, hdr->max_man_size);     /* Max. size of "managed" objects */
+    H5F_DECODE_LENGTH(udata->f, image, hdr->huge_next_id); /* Next ID to use for "huge" object */
+    H5F_addr_decode(udata->f, &image, &hdr->huge_bt2_addr); /* Address of "huge" object tracker B-tree */
 
     /* "Managed" object free space information */
-    H5F_DECODE_LENGTH(udata->f, p, hdr->total_man_free); /* Internal free space in managed direct blocks */
-    H5F_addr_decode(udata->f, &p, &hdr->fs_addr);      /* Address of free section header */
+    H5F_DECODE_LENGTH(udata->f, image, hdr->total_man_free); /* Internal free space in managed direct blocks */
+    H5F_addr_decode(udata->f, &image, &hdr->fs_addr);  /* Address of free section header */
 
     /* Heap statistics */
-    H5F_DECODE_LENGTH(udata->f, p, hdr->man_size);
-    H5F_DECODE_LENGTH(udata->f, p, hdr->man_alloc_size);
-    H5F_DECODE_LENGTH(udata->f, p, hdr->man_iter_off);
-    H5F_DECODE_LENGTH(udata->f, p, hdr->man_nobjs);
-    H5F_DECODE_LENGTH(udata->f, p, hdr->huge_size);
-    H5F_DECODE_LENGTH(udata->f, p, hdr->huge_nobjs);
-    H5F_DECODE_LENGTH(udata->f, p, hdr->tiny_size);
-    H5F_DECODE_LENGTH(udata->f, p, hdr->tiny_nobjs);
+    H5F_DECODE_LENGTH(udata->f, image, hdr->man_size);
+    H5F_DECODE_LENGTH(udata->f, image, hdr->man_alloc_size);
+    H5F_DECODE_LENGTH(udata->f, image, hdr->man_iter_off);
+    H5F_DECODE_LENGTH(udata->f, image, hdr->man_nobjs);
+    H5F_DECODE_LENGTH(udata->f, image, hdr->huge_size);
+    H5F_DECODE_LENGTH(udata->f, image, hdr->huge_nobjs);
+    H5F_DECODE_LENGTH(udata->f, image, hdr->tiny_size);
+    H5F_DECODE_LENGTH(udata->f, image, hdr->tiny_nobjs);
 
     /* Managed objects' doubling-table info */
-    if(H5HF__dtable_decode(hdr->f, &p, &(hdr->man_dtable)) < 0)
+    if(H5HF__dtable_decode(hdr->f, &image, &(hdr->man_dtable)) < 0)
         HGOTO_ERROR(H5E_HEAP, H5E_CANTENCODE, NULL, "unable to encode managed obj. doubling table info")
 
     /* Sanity check */
     /* (allow for checksum not decoded yet) */
-    HDassert((size_t)(p - (const uint8_t *)buf) == (size - H5HF_SIZEOF_CHKSUM));
+    HDassert((size_t)(image - (const uint8_t *)_image) == (size - H5HF_SIZEOF_CHKSUM));
 
     /* Check for I/O filter information to decode */
     if(hdr->filter_len > 0) {
-        size_t filter_info_off;     /* Offset in header of filter information */
         size_t filter_info_size;    /* Size of filter information */
         H5O_pline_t *pline;         /* Pipeline information from the header on disk */
 
-        /* Compute the offset of the filter info in the header */
-        filter_info_off = (size_t)(p - (const uint8_t *)buf);
-
         /* Compute the size of the extra filter information */
         filter_info_size = (size_t)(hdr->sizeof_size     /* Size of size for filtered root direct block */
             + (unsigned)4		/* Size of filter mask for filtered root direct block */
@@ -389,28 +497,27 @@ H5HF_cache_hdr_load(H5F_t *f, hid_t dxpl_id, haddr_t addr, void *_udata)
         /* Compute the heap header's size */
         hdr->heap_size = size + filter_info_size;
 
-        /* Re-size current buffer */
-        if(NULL == (buf = (uint8_t *)H5WB_actual(wb, hdr->heap_size)))
-            HGOTO_ERROR(H5E_HEAP, H5E_NOSPACE, NULL, "can't get actual buffer")
-
-        /* Read in I/O filter information */
-        /* (and the checksum) */
-        if(H5F_block_read(f, H5FD_MEM_FHEAP_HDR, (addr + filter_info_off), (filter_info_size + H5HF_SIZEOF_CHKSUM), dxpl_id, (buf + filter_info_off)) < 0)
-            HGOTO_ERROR(H5E_HEAP, H5E_READERROR, NULL, "can't read fractal heap header's I/O pipeline filter info")
+        if(size == len) 
+	    /* we were supplied with too small a buffer -- goto done
+             * and let H5C_load_entry() retry with a larger buffer
+             */
+	    HGOTO_DONE((void *)hdr)
 
-        /* Point at correct offset in header for the filter information */
-        p = buf + filter_info_off;
+	else
+            if((size + filter_info_size) != len)
+                HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, NULL, "bad image len")
 
         /* Decode the size of a filtered root direct block */
-        H5F_DECODE_LENGTH(udata->f, p, hdr->pline_root_direct_size);
+        H5F_DECODE_LENGTH(udata->f, image, hdr->pline_root_direct_size);
 
         /* Decode the filter mask for a filtered root direct block */
-        UINT32DECODE(p, hdr->pline_root_direct_filter_mask);
+        UINT32DECODE(image, hdr->pline_root_direct_filter_mask);
 
         /* Decode I/O filter information */
-        if(NULL == (pline = (H5O_pline_t *)H5O_msg_decode(hdr->f, udata->dxpl_id, NULL, H5O_PLINE_ID, p)))
+        if(NULL == (pline = (H5O_pline_t *)H5O_msg_decode(hdr->f, udata->dxpl_id, NULL, H5O_PLINE_ID, image)))
             HGOTO_ERROR(H5E_HEAP, H5E_CANTDECODE, NULL, "can't decode I/O pipeline filters")
-        p += hdr->filter_len;
+
+        image += hdr->filter_len;
 
         /* Copy the information into the header's I/O pipeline structure */
         if(NULL == H5O_msg_copy(H5O_PLINE_ID, pline, &(hdr->pline)))
@@ -425,13 +532,13 @@ H5HF_cache_hdr_load(H5F_t *f, hid_t dxpl_id, haddr_t addr, void *_udata)
 
     /* Compute checksum on entire header */
     /* (including the filter information, if present) */
-    computed_chksum = H5_checksum_metadata(buf, (size_t)(p - (const uint8_t *)buf), 0);
+    computed_chksum = H5_checksum_metadata(_image, (size_t)(image - (const uint8_t *)_image), 0);
 
     /* Metadata checksum */
-    UINT32DECODE(p, stored_chksum);
+    UINT32DECODE(image, stored_chksum);
 
     /* Sanity check */
-    HDassert((size_t)(p - (const uint8_t *)buf) == hdr->heap_size);
+    HDassert((size_t)(image - (const uint8_t *)_image) == hdr->heap_size);
 
     /* Verify checksum */
     if(stored_chksum != computed_chksum)
@@ -442,291 +549,324 @@ H5HF_cache_hdr_load(H5F_t *f, hid_t dxpl_id, haddr_t addr, void *_udata)
         HGOTO_ERROR(H5E_RESOURCE, H5E_CANTINIT, NULL, "can't finish initializing shared fractal heap header")
 
     /* Set return value */
-    ret_value = hdr;
+    ret_value = (void *)hdr;
 
 done:
-    /* Release resources */
-    if(wb && H5WB_unwrap(wb) < 0)
-        HDONE_ERROR(H5E_HEAP, H5E_CLOSEERROR, NULL, "can't close wrapped buffer")
     if(!ret_value && hdr)
         if(H5HF_hdr_free(hdr) < 0)
             HDONE_ERROR(H5E_HEAP, H5E_CANTRELEASE, NULL, "unable to release fractal heap header")
 
     FUNC_LEAVE_NOAPI(ret_value)
-} /* end H5HF_cache_hdr_load() */ /*lint !e818 Can't make udata a pointer to const */
+} /* end H5HF__cache_hdr_deserialize() */
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5HF_cache_hdr_flush
+ * Function:	H5HF__cache_hdr_image_len
  *
- * Purpose:	Flushes a dirty fractal heap header to disk.
+ * Purpose:	Return the actual size of the fractal heap header on 
+ *		disk image.  
  *
- * Return:	Non-negative on success/Negative on failure
+ *		If the header contains filter information, this size will be 
+ *		larger than the value returned by H5HF__cache_hdr_get_load_size().  
  *
- * Programmer:	Quincey Koziol
- *		koziol@ncsa.uiuc.edu
- *		Feb 24 2006
+ * Return:	Success:	SUCCEED
+ *		Failure:	FAIL
+ *
+ * Programmer:	John Mainzer
+ *		6/21/14
  *
  *-------------------------------------------------------------------------
  */
-static herr_t
-H5HF_cache_hdr_flush(H5F_t *f, hid_t dxpl_id, hbool_t destroy, haddr_t addr, H5HF_hdr_t *hdr, unsigned H5_ATTR_UNUSED * flags_ptr)
+static herr_t 
+H5HF__cache_hdr_image_len(const void *_thing, size_t *image_len,
+    hbool_t H5_ATTR_UNUSED *compressed_ptr, size_t H5_ATTR_UNUSED *compressed_image_len_ptr)
 {
-    H5WB_t *wb = NULL;                  /* Wrapped buffer for header data */
-    uint8_t hdr_buf[H5HF_HDR_BUF_SIZE]; /* Buffer for header */
-    herr_t ret_value = SUCCEED;         /* Return value */
+    const H5HF_hdr_t  *hdr = (const H5HF_hdr_t *)_thing;    /* Fractal heap info */
 
-    FUNC_ENTER_NOAPI_NOINIT
+    FUNC_ENTER_STATIC_NOERR
 
-    /* check arguments */
-    HDassert(f);
-    HDassert(H5F_addr_defined(addr));
+    /* Sanity checks */
     HDassert(hdr);
+    HDassert(hdr->cache_info.magic == H5C__H5C_CACHE_ENTRY_T_MAGIC);
+    HDassert(hdr->cache_info.type == H5AC_FHEAP_HDR);
+    HDassert(image_len);
 
-    if(hdr->cache_info.is_dirty) {
-        uint8_t	*buf;           /* Temporary raw data buffer */
-        uint8_t *p;             /* Pointer into raw data buffer */
-        size_t	size;           /* Header size on disk */
-        uint8_t heap_flags;     /* Status flags for heap */
-        uint32_t metadata_chksum; /* Computed metadata checksum value */
-
-#ifndef NDEBUG
-{
-        /* Verify that flush dependencies are working correctly.  Do this
-	 * by verifying that either:
-         *
-         * 1) the header has a root iblock, and that the root iblock and all
- 	 *    of its children are clean, or
-         *
-         * 2) The header has a root dblock, which is clean, or
-         *
-         * 3) The heap is empty, and thus the header has neither a root
-         *    iblock no a root dblock.  In this case, the flush ordering
-         *    constraint is met by default.
-	 *
- 	 * Do this with a call to H5HF__cache_verify_hdr_descendants_clean().
-	 */
-	hbool_t descendants_clean = TRUE;
+    *image_len = hdr->heap_size;
 
-	if(H5HF__cache_verify_hdr_descendants_clean(f, dxpl_id, hdr, &descendants_clean) < 0)
-	     HGOTO_ERROR(H5E_HEAP, H5E_SYSTEM, FAIL, "can't verify hdr descendants clean.")
-	HDassert(descendants_clean);
-}
-#endif /* NDEBUG */
+    FUNC_LEAVE_NOAPI(SUCCEED)
+} /* end H5HF__cache_hdr_image_len() */
 
-        /* Set the shared heap header's file context for this operation */
-        hdr->f = f;
-
-        /* Wrap the local buffer for serialized header info */
-        if(NULL == (wb = H5WB_wrap(hdr_buf, sizeof(hdr_buf))))
-            HGOTO_ERROR(H5E_HEAP, H5E_CANTINIT, FAIL, "can't wrap buffer")
-
-        /* Compute the size of the heap header on disk */
-        size = hdr->heap_size;
-
-        /* Get a pointer to a buffer that's large enough for serialized header */
-        if(NULL == (buf = (uint8_t *)H5WB_actual(wb, size)))
-            HGOTO_ERROR(H5E_HEAP, H5E_NOSPACE, FAIL, "can't get actual buffer")
-
-        /* Get temporary pointer to serialized header */
-        p = buf;
-
-        /* Magic number */
-        HDmemcpy(p, H5HF_HDR_MAGIC, (size_t)H5_SIZEOF_MAGIC);
-        p += H5_SIZEOF_MAGIC;
-
-        /* Version # */
-        *p++ = H5HF_HDR_VERSION;
-
-        /* General heap information */
-        UINT16ENCODE(p, hdr->id_len);           /* Heap ID length */
-        UINT16ENCODE(p, hdr->filter_len);       /* I/O filters' encoded length */
-
-        /* Heap status flags */
-        /* (bit 0: "huge" object IDs have wrapped) */
-        /* (bit 1: checksum direct blocks) */
-        heap_flags = 0;
-        heap_flags = (uint8_t)(heap_flags | (hdr->huge_ids_wrapped ? H5HF_HDR_FLAGS_HUGE_ID_WRAPPED : 0));
-        heap_flags = (uint8_t)(heap_flags | (hdr->checksum_dblocks ? H5HF_HDR_FLAGS_CHECKSUM_DBLOCKS : 0));
-        *p++ = heap_flags;
-
-        /* "Huge" object information */
-        UINT32ENCODE(p, hdr->max_man_size);             /* Max. size of "managed" objects */
-        H5F_ENCODE_LENGTH(f, p, hdr->huge_next_id);     /* Next ID to use for "huge" object */
-        H5F_addr_encode(f, &p, hdr->huge_bt2_addr);     /* Address of "huge" object tracker B-tree */
-
-        /* "Managed" object free space information */
-        H5F_ENCODE_LENGTH(f, p, hdr->total_man_free);   /* Internal free space in managed direct blocks */
-        H5F_addr_encode(f, &p, hdr->fs_addr);           /* Address of free section header */
-
-        /* Heap statistics */
-        H5F_ENCODE_LENGTH(f, p, hdr->man_size);
-        H5F_ENCODE_LENGTH(f, p, hdr->man_alloc_size);
-        H5F_ENCODE_LENGTH(f, p, hdr->man_iter_off);
-        H5F_ENCODE_LENGTH(f, p, hdr->man_nobjs);
-        H5F_ENCODE_LENGTH(f, p, hdr->huge_size);
-        H5F_ENCODE_LENGTH(f, p, hdr->huge_nobjs);
-        H5F_ENCODE_LENGTH(f, p, hdr->tiny_size);
-        H5F_ENCODE_LENGTH(f, p, hdr->tiny_nobjs);
-
-        /* Managed objects' doubling-table info */
-        if(H5HF__dtable_encode(hdr->f, &p, &(hdr->man_dtable)) < 0)
-	    HGOTO_ERROR(H5E_HEAP, H5E_CANTENCODE, FAIL, "unable to encode managed obj. doubling table info")
-
-        /* Check for I/O filter information to encode */
-        if(hdr->filter_len > 0) {
-            /* Encode the size of a filtered root direct block */
-            H5F_ENCODE_LENGTH(f, p, hdr->pline_root_direct_size);
+
+/*-------------------------------------------------------------------------
+ * Function:	H5HF__cache_hdr_pre_serialize
+ *
+ * Purpose:	As best I can tell, fractal heap header blocks are always 
+ *		allocated in real file space.  Thus this routine simply verifies
+ *		this, verifies that the len parameter contains the expected
+ *		value, and returns an error if either of these checks fail.
+ *
+ *		When compiled in debug mode, the function also verifies that all
+ *		indirect and direct blocks that are children of the header are 
+ *		either clean, or not in the metadata cache.
+ *
+ * Return:	Success:	SUCCEED
+ *		Failure:	FAIL
+ *
+ * Programmer:	John Mainzer
+ *		6/21/14
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t 
+H5HF__cache_hdr_pre_serialize(const H5F_t *f, hid_t dxpl_id, void *_thing,
+    haddr_t addr, size_t len, size_t H5_ATTR_UNUSED compressed_len, 
+    haddr_t H5_ATTR_UNUSED *new_addr, size_t H5_ATTR_UNUSED *new_len,
+    size_t H5_ATTR_UNUSED *new_compressed_len, unsigned *flags)
+{
+    H5HF_hdr_t *hdr = (H5HF_hdr_t *)_thing;     /* Fractal heap info */
+    herr_t      ret_value = SUCCEED;    /* Return value */
 
-            /* Encode the filter mask for a filtered root direct block */
-            UINT32ENCODE(p, hdr->pline_root_direct_filter_mask);
+    FUNC_ENTER_STATIC
 
-            /* Encode I/O filter information */
-            if(H5O_msg_encode(hdr->f, H5O_PLINE_ID, FALSE, p, &(hdr->pline)) < 0)
-                HGOTO_ERROR(H5E_HEAP, H5E_CANTENCODE, FAIL, "can't encode I/O pipeline fiters")
-            p += hdr->filter_len;
-        } /* end if */
+    /* Sanity checks */
+    HDassert(f);
+    HDassert(hdr);
+    HDassert(hdr->cache_info.magic == H5C__H5C_CACHE_ENTRY_T_MAGIC);
+    HDassert(hdr->cache_info.type == H5AC_FHEAP_HDR);
+    HDassert(H5F_addr_defined(addr));
+    HDassert(addr == hdr->heap_addr);
+    HDassert(new_addr);
+    HDassert(new_len);
+    HDassert(flags);
 
-        /* Compute metadata checksum */
-        metadata_chksum = H5_checksum_metadata(buf, (size_t)(p - buf), 0);
+#ifndef NDEBUG
+{
+    hbool_t descendants_clean = TRUE;
 
-        /* Metadata checksum */
-        UINT32ENCODE(p, metadata_chksum);
+    /* Verify that flush dependencies are working correctly.  Do this
+     * by verifying that either:
+     *
+     * 1) the header has a root iblock, and that the root iblock and all
+     *    of its children are clean, or
+     *
+     * 2) The header has a root dblock, which is clean, or
+     *
+     * 3) The heap is empty, and thus the header has neither a root
+     *    iblock no a root dblock.  In this case, the flush ordering
+     *    constraint is met by default.
+     *
+     * Do this with a call to H5HF__cache_verify_hdr_descendants_clean().
+     */
+    if(H5HF__cache_verify_hdr_descendants_clean((H5F_t *)f, dxpl_id, hdr, &descendants_clean) < 0)
+         HGOTO_ERROR(H5E_HEAP, H5E_SYSTEM, FAIL, "can't verify hdr descendants clean.")
+    HDassert(descendants_clean);
+}
+#endif /* NDEBUG */
 
-	/* Write the heap header. */
-        HDassert((size_t)(p - buf) == size);
-	if(H5F_block_write(f, H5FD_MEM_FHEAP_HDR, addr, size, dxpl_id, buf) < 0)
-	    HGOTO_ERROR(H5E_HEAP, H5E_CANTFLUSH, FAIL, "unable to save fractal heap header to disk")
+    if(H5F_IS_TMP_ADDR(f, addr))
+        HGOTO_ERROR(H5E_HEAP, H5E_BADVALUE, FAIL, "addr in temporary space?!?.");
 
-	hdr->cache_info.is_dirty = FALSE;
-    } /* end if */
+    if(len != hdr->heap_size)
+        HGOTO_ERROR(H5E_HEAP, H5E_BADVALUE, FAIL, "unexpected image len.");
 
-    if(destroy)
-        if(H5HF_cache_hdr_dest(f, hdr) < 0)
-	    HGOTO_ERROR(H5E_HEAP, H5E_CANTFREE, FAIL, "unable to destroy fractal heap header")
+    *flags = 0;
 
 done:
-    /* Release resources */
-    if(wb && H5WB_unwrap(wb) < 0)
-        HDONE_ERROR(H5E_HEAP, H5E_CLOSEERROR, FAIL, "can't close wrapped buffer")
-
     FUNC_LEAVE_NOAPI(ret_value)
-} /* H5HF_cache_hdr_flush() */
+} /* end H5HF__cache_hdr_pre_serialize() */
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5HF_cache_hdr_dest
+ * Function:	H5HF__cache_hdr_serialize
  *
- * Purpose:	Destroys a fractal heap header in memory.
+ * Purpose:	Construct the on disk image of the header, and place it in 
+ *		the buffer pointed to by image.  Return SUCCEED on success,
+ *		and FAIL on failure.
  *
- * Return:	Non-negative on success/Negative on failure
+ * Return:	Success:	SUCCEED
+ *		Failure:	FAIL
  *
- * Programmer:	Quincey Koziol
- *		koziol@ncsa.uiuc.edu
- *		Feb 24 2006
+ * Programmer:	John Mainzer
+ *		6/21/14
  *
  *-------------------------------------------------------------------------
  */
-static herr_t
-H5HF_cache_hdr_dest(H5F_t *f, H5HF_hdr_t *hdr)
+static herr_t 
+H5HF__cache_hdr_serialize(const H5F_t *f, void *_image, size_t len,
+    void *_thing)
 {
+    H5HF_hdr_t *hdr = (H5HF_hdr_t *)_thing;     /* Fractal heap info */
+    uint8_t    *image = (uint8_t *)_image;      /* Pointer into raw data buffer */
+    uint8_t 	heap_flags;             /* Status flags for heap */
+    uint32_t 	metadata_chksum;        /* Computed metadata checksum value */
     herr_t      ret_value = SUCCEED;    /* Return value */
 
-    FUNC_ENTER_NOAPI_NOINIT
+    FUNC_ENTER_STATIC
 
-    /*
-     * Check arguments.
-     */
+    /* Sanity checks */
+    HDassert(f);
+    HDassert(image);
     HDassert(hdr);
-    HDassert(hdr->rc == 0);
+    HDassert(hdr->cache_info.magic == H5C__H5C_CACHE_ENTRY_T_MAGIC);
+    HDassert(hdr->cache_info.type == H5AC_FHEAP_HDR);
+    HDassert(len == hdr->heap_size);
 
-    /* If we're going to free the space on disk, the address must be valid */
-    HDassert(!hdr->cache_info.free_file_space_on_destroy || H5F_addr_defined(hdr->cache_info.addr));
+    /* Set the shared heap header's file context for this operation */
+    hdr->f = f;
+
+    /* Magic number */
+    HDmemcpy(image, H5HF_HDR_MAGIC, (size_t)H5_SIZEOF_MAGIC);
+    image += H5_SIZEOF_MAGIC;
 
-    /* Check for freeing file space for heap header */
-    if(hdr->cache_info.free_file_space_on_destroy) {
-        /* Release the space on disk */
-        /* (XXX: Nasty usage of internal DXPL value! -QAK) */
-        if(H5MF_xfree(f, H5FD_MEM_FHEAP_HDR, H5AC_dxpl_id, hdr->cache_info.addr, (hsize_t)hdr->heap_size) < 0)
-            HGOTO_ERROR(H5E_HEAP, H5E_CANTFREE, FAIL, "unable to free fractal heap header")
+    /* Version # */
+    *image++ = H5HF_HDR_VERSION;
+
+    /* General heap information */
+    UINT16ENCODE(image, hdr->id_len);           /* Heap ID length */
+    UINT16ENCODE(image, hdr->filter_len);       /* I/O filters' encoded length */
+
+    /* Heap status flags */
+    /* (bit 0: "huge" object IDs have wrapped) */
+    /* (bit 1: checksum direct blocks) */
+    heap_flags = 0;
+    heap_flags = (uint8_t)(heap_flags | (hdr->huge_ids_wrapped ? H5HF_HDR_FLAGS_HUGE_ID_WRAPPED : 0));
+    heap_flags = (uint8_t)(heap_flags | (hdr->checksum_dblocks ? H5HF_HDR_FLAGS_CHECKSUM_DBLOCKS : 0));
+    *image++ = heap_flags;
+
+    /* "Huge" object information */
+    UINT32ENCODE(image, hdr->max_man_size);   /* Max. size of "managed" objects */
+    H5F_ENCODE_LENGTH(f, image, hdr->huge_next_id); /* Next ID to use for "huge" object */
+    H5F_addr_encode(f, &image, hdr->huge_bt2_addr); /* Address of "huge" object tracker B-tree */
+
+    /* "Managed" object free space information */
+    H5F_ENCODE_LENGTH(f, image, hdr->total_man_free); /* Internal free space in managed direct blocks */
+    H5F_addr_encode(f, &image, hdr->fs_addr); /* Address of free section header */
+
+    /* Heap statistics */
+    H5F_ENCODE_LENGTH(f, image, hdr->man_size);
+    H5F_ENCODE_LENGTH(f, image, hdr->man_alloc_size);
+    H5F_ENCODE_LENGTH(f, image, hdr->man_iter_off);
+    H5F_ENCODE_LENGTH(f, image, hdr->man_nobjs);
+    H5F_ENCODE_LENGTH(f, image, hdr->huge_size);
+    H5F_ENCODE_LENGTH(f, image, hdr->huge_nobjs);
+    H5F_ENCODE_LENGTH(f, image, hdr->tiny_size);
+    H5F_ENCODE_LENGTH(f, image, hdr->tiny_nobjs);
+
+    /* Managed objects' doubling-table info */
+    if(H5HF__dtable_encode(hdr->f, &image, &(hdr->man_dtable)) < 0)
+        HGOTO_ERROR(H5E_HEAP, H5E_CANTENCODE, FAIL, "unable to encode managed obj. doubling table info")
+
+    /* Check for I/O filter information to encode */
+    if(hdr->filter_len > 0) {
+        /* Encode the size of a filtered root direct block */
+        H5F_ENCODE_LENGTH(f, image, hdr->pline_root_direct_size);
+
+        /* Encode the filter mask for a filtered root direct block */
+        UINT32ENCODE(image, hdr->pline_root_direct_filter_mask);
+
+        /* Encode I/O filter information */
+        if(H5O_msg_encode(hdr->f, H5O_PLINE_ID, FALSE, image, &(hdr->pline)) < 0)
+            HGOTO_ERROR(H5E_HEAP, H5E_CANTENCODE, FAIL, "can't encode I/O pipeline fiters")
+        image += hdr->filter_len;
     } /* end if */
 
-    /* Free the shared info itself */
-    if(H5HF_hdr_free(hdr) < 0)
-        HGOTO_ERROR(H5E_HEAP, H5E_CANTRELEASE, FAIL, "unable to release fractal heap header")
+    /* Compute metadata checksum */
+    metadata_chksum = H5_checksum_metadata(_image, (size_t)(image - (uint8_t *)_image), 0);
+
+    /* Metadata checksum */
+    UINT32ENCODE(image, metadata_chksum);
+
+    /* sanity check */
+    HDassert((size_t)(image - (uint8_t *)_image) == len);
 
 done:
     FUNC_LEAVE_NOAPI(ret_value)
-} /* end H5HF_cache_hdr_dest() */
+} /* end H5HF__cache_hdr_serialize() */
+
+/***************************************/
+/* no H5HF__cache_hdr_notify() function */
+/***************************************/
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5HF_cache_hdr_clear
+ * Function:	H5HF__cache_hdr_free_icr
  *
- * Purpose:	Mark a fractal heap header in memory as non-dirty.
+ * Purpose:	Free the in core representation of the fractal heap header.
  *
- * Return:	Non-negative on success/Negative on failure
+ *		This routine frees just the header itself, not the 
+ *		associated version 2 B-Tree, the associated Free Space Manager,
+ *		nor the indirect/direct block tree that is rooted in the header.
  *
- * Programmer:	Quincey Koziol
- *		koziol@ncsa.uiuc.edu
- *		Feb 24 2006
+ *		This routine also does not free the file space that may
+ *		be allocated to the header.
+ *
+ * Note:	The metadata cache sets the object's cache_info.magic to
+ *		H5C__H5C_CACHE_ENTRY_T_BAD_MAGIC before calling a free_icr
+ *		callback (checked in assert).
+ *
+ * Return:	Success:	SUCCEED
+ *		Failure:	FAIL
+ *
+ * Programmer:	John Mainzer
+ *		6/21/14
  *
  *-------------------------------------------------------------------------
  */
-static herr_t
-H5HF_cache_hdr_clear(H5F_t *f, H5HF_hdr_t *hdr, hbool_t destroy)
+static herr_t 
+H5HF__cache_hdr_free_icr(void *_thing)
 {
-    herr_t ret_value = SUCCEED;         /* Return value */
+    H5HF_hdr_t *hdr = (H5HF_hdr_t *)_thing;     /* Fractal heap info */
+    herr_t      ret_value = SUCCEED;            /* Return value */
 
-    FUNC_ENTER_NOAPI_NOINIT
+    FUNC_ENTER_STATIC
 
-    /*
-     * Check arguments.
-     */
+    /* Sanity checks */
     HDassert(hdr);
+    HDassert(hdr->cache_info.magic == H5C__H5C_CACHE_ENTRY_T_BAD_MAGIC);
+    HDassert(hdr->cache_info.type == H5AC_FHEAP_HDR);
+    HDassert(hdr->rc == 0);
 
-    /* Reset the dirty flag.  */
-    hdr->cache_info.is_dirty = FALSE;
-
-    if(destroy)
-        if(H5HF_cache_hdr_dest(f, hdr) < 0)
-	    HGOTO_ERROR(H5E_HEAP, H5E_CANTFREE, FAIL, "unable to destroy fractal heap header")
+    if(H5HF_hdr_free(hdr) < 0)
+        HGOTO_ERROR(H5E_HEAP, H5E_CANTRELEASE, FAIL, "unable to release fractal heap header")
 
 done:
     FUNC_LEAVE_NOAPI(ret_value)
-} /* end H5HF_cache_hdr_clear() */
+} /* end H5HF__cache_hdr_free_icr() */
+
+/***********************************************************/
+/* metadata cache callback definitions for indirect blocks */
+/***********************************************************/
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5HF_cache_hdr_size
+ * Function:	H5HF__cache_iblock_get_load_size()
  *
- * Purpose:	Compute the size in bytes of a fractal heap header
- *		on disk, and return it in *size_ptr.  On failure,
- *		the value of *size_ptr is undefined.
+ * Purpose:	Compute the size of the on disk image of the indirect 
+ *		block, and place this value in *image_len.
  *
- * Return:	Non-negative on success/Negative on failure
+ * Return:	Success:	SUCCEED
+ *		Failure:	FAIL
  *
- * Programmer:	Quincey Koziol
- *		koziol@ncsa.uiuc.edu
- *		Feb 24 2006
+ * Programmer:	John Mainzer
+ *		6/21/14
  *
  *-------------------------------------------------------------------------
  */
-static herr_t
-H5HF_cache_hdr_size(const H5F_t H5_ATTR_UNUSED *f, const H5HF_hdr_t *hdr, size_t *size_ptr)
+static herr_t 
+H5HF__cache_iblock_get_load_size(const void *_udata, size_t *image_len)
 {
-    FUNC_ENTER_NOAPI_NOINIT_NOERR
+    const H5HF_iblock_cache_ud_t *udata = (const H5HF_iblock_cache_ud_t *)_udata;   /* User data for callback */
 
-    /* Check arguments */
-    HDassert(f);
-    HDassert(hdr);
-    HDassert(size_ptr);
+    FUNC_ENTER_STATIC_NOERR
 
-    /* Set size value */
-    *size_ptr = hdr->heap_size;
+    /* Sanity checks */
+    HDassert(udata);
+    HDassert(image_len);
+   
+    *image_len = (size_t)H5HF_MAN_INDIRECT_SIZE(udata->par_info->hdr, *udata->nrows);
 
     FUNC_LEAVE_NOAPI(SUCCEED)
-} /* H5HF_cache_hdr_size() */
+} /* end H5HF__cache_iblock_get_load_size() */
 
 /***********************************************************/
 /* metadata cache callback definitions for indirect blocks */
@@ -734,53 +874,55 @@ H5HF_cache_hdr_size(const H5F_t H5_ATTR_UNUSED *f, const H5HF_hdr_t *hdr, size_t
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5HF_cache_iblock_load
+ * Function:	H5HF__cache_iblock_deserialize
  *
- * Purpose:	Loads a fractal heap indirect block from the disk.
+ * Purpose:	Given a buffer containing the on disk image of the indirect 
+ *		block, allocate an instance of H5HF_indirect_t, load the data 
+ *		in the buffer into this new instance, and return a pointer to 
+ *		it.
  *
- * Return:	Success:	Pointer to a new fractal heap indirect block
+ *		As best I can tell, the size of the indirect block image is fully
+ *		know before the image is loaded, so this function should succeed
+ *		unless the image is corrupt or memory allocation fails.
  *
+ * Return:	Success:	Pointer to in core representation
  *		Failure:	NULL
  *
- * Programmer:	Quincey Koziol
- *		koziol@ncsa.uiuc.edu
- *		Feb 27 2006
+ * Programmer:	John Mainzer
+ *		6/21/14
  *
  *-------------------------------------------------------------------------
  */
-static H5HF_indirect_t *
-H5HF_cache_iblock_load(H5F_t *f, hid_t dxpl_id, haddr_t addr, void *_udata)
+static void *
+H5HF__cache_iblock_deserialize(const void *_image, size_t len, void *_udata,
+    hbool_t H5_ATTR_UNUSED *dirty)
 {
     H5HF_hdr_t          *hdr;           /* Shared fractal heap information */
-    H5HF_iblock_cache_ud_t *udata = (H5HF_iblock_cache_ud_t *)_udata; /* user data for callback */
-    H5HF_indirect_t	*iblock = NULL; /* Indirect block info */
-    H5WB_t              *wb = NULL;     /* Wrapped buffer for indirect block data */
-    uint8_t             iblock_buf[H5HF_IBLOCK_BUF_SIZE]; /* Buffer for indirect block */
-    uint8_t		*buf;           /* Temporary buffer */
-    const uint8_t	*p;             /* Pointer into raw data buffer */
+    H5HF_iblock_cache_ud_t *udata = (H5HF_iblock_cache_ud_t *)_udata; /* User data for callback */
+    H5HF_indirect_t     *iblock = NULL; /* Indirect block info */
+    const uint8_t       *image = (const uint8_t *)_image;       /* Pointer into raw data buffer */
     haddr_t             heap_addr;      /* Address of heap header in the file */
     uint32_t            stored_chksum;  /* Stored metadata checksum value */
     uint32_t            computed_chksum; /* Computed metadata checksum value */
     unsigned            u;              /* Local index variable */
-    H5HF_indirect_t	*ret_value;     /* Return value */
+    void *              ret_value;      /* Return value */
 
-    FUNC_ENTER_NOAPI_NOINIT
+    FUNC_ENTER_STATIC
 
-    /* Check arguments */
-    HDassert(f);
-    HDassert(H5F_addr_defined(addr));
+    /* Sanity checks */
+    HDassert(image);
     HDassert(udata);
-
-    /* Allocate space for the fractal heap indirect block */
-    if(NULL == (iblock = H5FL_CALLOC(H5HF_indirect_t)))
-        HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, NULL, "memory allocation failed")
-
-    /* Get the pointer to the shared heap header */
+    HDassert(dirty);
     hdr = udata->par_info->hdr;
+    HDassert(hdr->f);
 
     /* Set the shared heap header's file context for this operation */
     hdr->f = udata->f;
 
+    /* Allocate space for the fractal heap indirect block */
+    if(NULL == (iblock = H5FL_CALLOC(H5HF_indirect_t)))
+        HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, NULL, "memory allocation failed")
+
     /* Share common heap information */
     iblock->hdr = hdr;
     if(H5HF_hdr_incr(hdr) < 0)
@@ -791,35 +933,23 @@ H5HF_cache_iblock_load(H5F_t *f, hid_t dxpl_id, haddr_t addr, void *_udata)
     iblock->nrows = *udata->nrows;
     iblock->nchildren = 0;
 
-    /* Wrap the local buffer for serialized indirect block */
-    if(NULL == (wb = H5WB_wrap(iblock_buf, sizeof(iblock_buf))))
-        HGOTO_ERROR(H5E_HEAP, H5E_CANTINIT, NULL, "can't wrap buffer")
-
     /* Compute size of indirect block */
     iblock->size = H5HF_MAN_INDIRECT_SIZE(hdr, iblock->nrows);
 
-    /* Get a pointer to a buffer that's large enough for serialized indirect block */
-    if(NULL == (buf = (uint8_t *)H5WB_actual(wb, iblock->size)))
-        HGOTO_ERROR(H5E_HEAP, H5E_NOSPACE, NULL, "can't get actual buffer")
-
-    /* Read indirect block from disk */
-    if(H5F_block_read(f, H5FD_MEM_FHEAP_IBLOCK, addr, iblock->size, dxpl_id, buf) < 0)
-	HGOTO_ERROR(H5E_HEAP, H5E_READERROR, NULL, "can't read fractal heap indirect block")
-
-    /* Get temporary pointer to serialized indirect block */
-    p = buf;
+    /* sanity check */
+    HDassert(iblock->size == len);
 
     /* Magic number */
-    if(HDmemcmp(p, H5HF_IBLOCK_MAGIC, (size_t)H5_SIZEOF_MAGIC))
-        HGOTO_ERROR(H5E_HEAP, H5E_CANTLOAD, NULL, "wrong fractal heap indirect block signature")
-    p += H5_SIZEOF_MAGIC;
+    if(HDmemcmp(image, H5HF_IBLOCK_MAGIC, (size_t)H5_SIZEOF_MAGIC))
+        HGOTO_ERROR(H5E_HEAP, H5E_BADVALUE, NULL, "wrong fractal heap indirect block signature")
+    image += H5_SIZEOF_MAGIC;
 
     /* Version */
-    if(*p++ != H5HF_IBLOCK_VERSION)
+    if(*image++ != H5HF_IBLOCK_VERSION)
         HGOTO_ERROR(H5E_HEAP, H5E_VERSION, NULL, "wrong fractal heap direct block version")
 
     /* Address of heap that owns this block */
-    H5F_addr_decode(udata->f, &p, &heap_addr);
+    H5F_addr_decode(udata->f, &image, &heap_addr);
     if(H5F_addr_ne(heap_addr, hdr->heap_addr))
         HGOTO_ERROR(H5E_HEAP, H5E_CANTLOAD, NULL, "incorrect heap header address for direct block")
 
@@ -844,7 +974,7 @@ H5HF_cache_iblock_load(H5F_t *f, hid_t dxpl_id, haddr_t addr, void *_udata)
     } /* end else */
 
     /* Offset of heap within the heap's address space */
-    UINT64DECODE_VAR(p, iblock->block_off, hdr->heap_off_size);
+    UINT64DECODE_VAR(image, iblock->block_off, hdr->heap_off_size);
 
     /* Allocate & decode child block entry tables */
     HDassert(iblock->nrows > 0);
@@ -866,7 +996,7 @@ H5HF_cache_iblock_load(H5F_t *f, hid_t dxpl_id, haddr_t addr, void *_udata)
 
     for(u = 0; u < (iblock->nrows * hdr->man_dtable.cparam.width); u++) {
         /* Decode child block address */
-        H5F_addr_decode(udata->f, &p, &(iblock->ents[u].addr));
+        H5F_addr_decode(udata->f, &image, &(iblock->ents[u].addr));
 
         /* Check for heap with I/O filters */
         if(hdr->filter_len > 0) {
@@ -876,7 +1006,7 @@ H5HF_cache_iblock_load(H5F_t *f, hid_t dxpl_id, haddr_t addr, void *_udata)
             /* Decode extra information for direct blocks */
             if(u < (hdr->man_dtable.max_direct_rows * hdr->man_dtable.cparam.width)) {
                 /* Size of filtered direct block */
-                H5F_DECODE_LENGTH(udata->f, p, iblock->filt_ents[u].size);
+                H5F_DECODE_LENGTH(udata->f, image, iblock->filt_ents[u].size);
 
                 /* Sanity check */
                 /* (either both the address & size are defined or both are
@@ -886,7 +1016,7 @@ H5HF_cache_iblock_load(H5F_t *f, hid_t dxpl_id, haddr_t addr, void *_udata)
                     || (!H5F_addr_defined(iblock->ents[u].addr) && iblock->filt_ents[u].size == 0));
 
                 /* I/O filter mask for filtered direct block */
-                UINT32DECODE(p, iblock->filt_ents[u].filter_mask);
+                UINT32DECODE(image, iblock->filt_ents[u].filter_mask);
             } /* end if */
         } /* end if */
 
@@ -901,13 +1031,13 @@ H5HF_cache_iblock_load(H5F_t *f, hid_t dxpl_id, haddr_t addr, void *_udata)
     HDassert(iblock->nchildren);   /* indirect blocks w/no children should have been deleted */
 
     /* Compute checksum on indirect block */
-    computed_chksum = H5_checksum_metadata(buf, (size_t)(p - (const uint8_t *)buf), 0);
+    computed_chksum = H5_checksum_metadata((const uint8_t *)_image, (size_t)(image - (const uint8_t *)_image), 0);
 
     /* Metadata checksum */
-    UINT32DECODE(p, stored_chksum);
+    UINT32DECODE(image, stored_chksum);
 
     /* Sanity check */
-    HDassert((size_t)(p - (const uint8_t *)buf) == iblock->size);
+    HDassert((size_t)(image - (const uint8_t *)_image) == iblock->size);
 
     /* Verify checksum */
     if(stored_chksum != computed_chksum)
@@ -915,7 +1045,7 @@ H5HF_cache_iblock_load(H5F_t *f, hid_t dxpl_id, haddr_t addr, void *_udata)
 
     /* Check if we have any indirect block children */
     if(iblock->nrows > hdr->man_dtable.max_direct_rows) {
-        unsigned indir_rows;      /* Number of indirect rows in this indirect block */
+        unsigned indir_rows;/* Number of indirect rows in this indirect block */
 
         /* Compute the number of indirect rows for this indirect block */
         indir_rows = iblock->nrows - hdr->man_dtable.max_direct_rows;
@@ -928,343 +1058,323 @@ H5HF_cache_iblock_load(H5F_t *f, hid_t dxpl_id, haddr_t addr, void *_udata)
         iblock->child_iblocks = NULL;
 
     /* Set return value */
-    ret_value = iblock;
+    ret_value = (void *)iblock;
 
 done:
-    /* Release resources */
-    if(wb && H5WB_unwrap(wb) < 0)
-        HDONE_ERROR(H5E_HEAP, H5E_CLOSEERROR, NULL, "can't close wrapped buffer")
     if(!ret_value && iblock)
         if(H5HF_man_iblock_dest(iblock) < 0)
             HDONE_ERROR(H5E_HEAP, H5E_CANTFREE, NULL, "unable to destroy fractal heap indirect block")
 
     FUNC_LEAVE_NOAPI(ret_value)
-} /* end H5HF_cache_iblock_load() */
+} /* end H5HF__cache_iblock_deserialize() */
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5HF_cache_iblock_flush
+ * Function:	H5HF__cache_iblock_image_len
  *
- * Purpose:	Flushes a dirty fractal heap indirect block to disk.
+ * Purpose:	Return the size of the on disk image of the iblock.
  *
- * Return:	Non-negative on success/Negative on failure
+ * Return:	Success:	SUCCEED
+ *		Failure:	FAIL
  *
- * Programmer:	Quincey Koziol
- *		koziol@ncsa.uiuc.edu
- *		Mar  6 2006
+ * Programmer:	John Mainzer
+ *		6/21/14
  *
  *-------------------------------------------------------------------------
  */
-static herr_t
-H5HF_cache_iblock_flush(H5F_t *f, hid_t dxpl_id, hbool_t destroy, haddr_t addr, H5HF_indirect_t *iblock, unsigned H5_ATTR_UNUSED * flags_ptr)
+static herr_t 
+H5HF__cache_iblock_image_len(const void *_thing, size_t *image_len,
+    hbool_t H5_ATTR_UNUSED *compressed_ptr, size_t H5_ATTR_UNUSED *compressed_image_len_ptr)
 {
-    H5WB_t      *wb = NULL;             /* Wrapped buffer for indirect block data */
-    uint8_t     iblock_buf[H5HF_IBLOCK_BUF_SIZE]; /* Buffer for indirect block */
-    herr_t      ret_value = SUCCEED;    /* Return value */
+    const H5HF_indirect_t *iblock = (const H5HF_indirect_t *)_thing;    /* Indirect block info */
 
-    FUNC_ENTER_NOAPI_NOINIT
+    FUNC_ENTER_STATIC_NOERR
 
-    /* check arguments */
-    HDassert(f);
-    HDassert(H5F_addr_defined(addr));
+    /* Sanity checks */
     HDassert(iblock);
+    HDassert(iblock->cache_info.magic == H5C__H5C_CACHE_ENTRY_T_MAGIC);
+    HDassert(iblock->cache_info.type == H5AC_FHEAP_IBLOCK);
+    HDassert(image_len);
 
-    if(iblock->cache_info.is_dirty) {
-        H5HF_hdr_t *hdr;                /* Shared fractal heap information */
-        uint8_t	*buf;                   /* Temporary buffer */
-        uint8_t *p;                     /* Pointer into raw data buffer */
-#ifndef NDEBUG
-        unsigned nchildren = 0;         /* Track # of children */
-        unsigned max_child = 0;         /* Track max. child entry used */
-#endif /* NDEBUG */
-        uint32_t metadata_chksum;       /* Computed metadata checksum value */
-        size_t u;                       /* Local index variable */
-
-#ifndef NDEBUG
-{
-        /* Verify that flush dependencies are working correctly.  Do this 
-	 * by verifying that all children of this iblock are clean.
-	 */
-	hbool_t descendants_clean = TRUE;
-	unsigned iblock_status;
-
-        if(H5AC_get_entry_status(f, iblock->addr, &iblock_status) < 0)
-            HGOTO_ERROR(H5E_HEAP, H5E_CANTGET, FAIL, "can't get iblock status")
-
-	/* since the current iblock is the guest of honor in a flush, we know
-         * that it is locked into the cache for the duration of the call.  Hence
-         * there is no need to check to see if it is pinned or protected, or to
-         * protect it if it is not.
-         */
-	if(H5HF__cache_verify_iblock_descendants_clean(f, dxpl_id, iblock, &iblock_status, &descendants_clean) < 0)
-	     HGOTO_ERROR(H5E_HEAP, H5E_SYSTEM, FAIL, "can't verify descendants clean.")
-
-	HDassert(descendants_clean);
-}
-#endif /* NDEBUG */
-
-        /* Get the pointer to the shared heap header */
-        hdr = iblock->hdr;
-
-        /* Set the shared heap header's file context for this operation */
-        hdr->f = f;
-
-        /* Wrap the local buffer for serialized indirect block */
-        if(NULL == (wb = H5WB_wrap(iblock_buf, sizeof(iblock_buf))))
-            HGOTO_ERROR(H5E_HEAP, H5E_CANTINIT, FAIL, "can't wrap buffer")
-
-        /* Get a pointer to a buffer that's large enough for serialized indirect block */
-        if(NULL == (buf = (uint8_t *)H5WB_actual(wb, iblock->size)))
-            HGOTO_ERROR(H5E_HEAP, H5E_NOSPACE, FAIL, "can't get actual buffer")
-
-        /* Get temporary pointer to buffer for serialized indirect block */
-        p = buf;
-
-        /* Magic number */
-        HDmemcpy(p, H5HF_IBLOCK_MAGIC, (size_t)H5_SIZEOF_MAGIC);
-        p += H5_SIZEOF_MAGIC;
-
-        /* Version # */
-        *p++ = H5HF_IBLOCK_VERSION;
-
-        /* Address of heap header for heap which owns this block */
-        H5F_addr_encode(f, &p, hdr->heap_addr);
-
-        /* Offset of block in heap */
-        UINT64ENCODE_VAR(p, iblock->block_off, hdr->heap_off_size);
-
-        /* Encode indirect block-specific fields */
-        for(u = 0; u < (iblock->nrows * hdr->man_dtable.cparam.width); u++) {
-            /* Encode child block address */
-            H5F_addr_encode(f, &p, iblock->ents[u].addr);
+    *image_len = iblock->size;
 
-            /* Check for heap with I/O filters */
-            if(hdr->filter_len > 0) {
-                /* Sanity check */
-                HDassert(iblock->filt_ents);
+    FUNC_LEAVE_NOAPI(SUCCEED)
+} /* end H5HF__cache_iblock_image_len() */
 
-                /* Encode extra information for direct blocks */
-                if(u < (hdr->man_dtable.max_direct_rows * hdr->man_dtable.cparam.width)) {
-                    /* Sanity check */
-                    /* (either both the address & size are defined or both are
-                     *  not defined)
-                     */
-                    HDassert((H5F_addr_defined(iblock->ents[u].addr) && iblock->filt_ents[u].size)
-                        || (!H5F_addr_defined(iblock->ents[u].addr) && iblock->filt_ents[u].size == 0));
+
+/*-------------------------------------------------------------------------
+ * Function:	H5HF__cache_iblock_pre_serialize
+ *
+ * Purpose:	The primary objective of this function is to determine if the
+ *		indirect block is currently allocated in temporary file space,
+ *		and if so, to move it to real file space before the entry is 
+ *		serialized.
+ *
+ *		In debug compiles, this function also verifies that all children
+ *		of this indirect block are either clean or are not in cache.
+ *
+ * Return:	Success:	SUCCEED
+ *		Failure:	FAIL
+ *
+ * Programmer:	John Mainzer
+ *		6/21/14
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t 
+H5HF__cache_iblock_pre_serialize(const H5F_t *f, hid_t dxpl_id, void *_thing,
+    haddr_t addr, size_t H5_ATTR_UNUSED len, size_t H5_ATTR_UNUSED compressed_len,
+    haddr_t *new_addr, size_t H5_ATTR_UNUSED *new_len,
+    size_t H5_ATTR_UNUSED *new_compressed_len, unsigned *flags)
+{
+    H5HF_hdr_t          *hdr;                   /* Shared fractal heap information */
+    H5HF_indirect_t     *iblock = (H5HF_indirect_t *)_thing;    /* Indirect block info */
+    herr_t      	 ret_value = SUCCEED;    /* Return value */
 
-                    /* Size of filtered direct block */
-                    H5F_ENCODE_LENGTH(f, p, iblock->filt_ents[u].size);
+    FUNC_ENTER_STATIC
 
-                    /* I/O filter mask for filtered direct block */
-                    UINT32ENCODE(p, iblock->filt_ents[u].filter_mask);
-                } /* end if */
-            } /* end if */
+    /* Sanity checks */
+    HDassert(f);
+    HDassert(iblock);
+    HDassert(iblock->cache_info.magic == H5C__H5C_CACHE_ENTRY_T_MAGIC);
+    HDassert(iblock->cache_info.type == H5AC_FHEAP_IBLOCK);
+    HDassert(iblock->cache_info.size == iblock->size);
+    HDassert(H5F_addr_defined(addr));
+    HDassert(H5F_addr_eq(iblock->addr, addr));
+    HDassert(new_addr);
+    HDassert(new_len);
+    HDassert(flags);
+    hdr = iblock->hdr;
+    HDassert(hdr);
+    HDassert(hdr->cache_info.magic == H5C__H5C_CACHE_ENTRY_T_MAGIC);
+    HDassert(hdr->cache_info.type == H5AC_FHEAP_HDR);
 
 #ifndef NDEBUG
-            /* Count child blocks */
-            if(H5F_addr_defined(iblock->ents[u].addr)) {
-                nchildren++;
-                if(u > max_child)
-                    max_child = u;
-            } /* end if */
-#endif /* NDEBUG */
-        } /* end for */
-
-        /* Compute checksum */
-        metadata_chksum = H5_checksum_metadata(buf, (size_t)(p - buf), 0);
+{
+    hbool_t 		 descendants_clean = TRUE;
+    unsigned 		 iblock_status = 0;
 
-        /* Metadata checksum */
-        UINT32ENCODE(p, metadata_chksum);
+    /* verify that flush dependencies are working correctly.  Do this
+     * by verifying that all children of this iblock are clean.
+     */
+    if(H5AC_get_entry_status(f, iblock->addr, &iblock_status) < 0)
+        HGOTO_ERROR(H5E_HEAP, H5E_CANTGET, FAIL, "can't get iblock status")
 
-        /* Sanity check */
-        HDassert((size_t)(p - buf) == iblock->size);
-#ifndef NDEBUG
-        HDassert(nchildren == iblock->nchildren);
-        HDassert(max_child == iblock->max_child);
+    /* since the current iblock is the guest of honor in a flush, we know
+     * that it is locked into the cache for the duration of the call.  Hence
+     * there is no need to check to see if it is pinned or protected, or to
+     * protect it if it is not.
+     */
+    if(H5HF__cache_verify_iblock_descendants_clean((H5F_t *)f, dxpl_id, iblock, &iblock_status, &descendants_clean) < 0)
+         HGOTO_ERROR(H5E_HEAP, H5E_SYSTEM, FAIL, "can't verify descendants clean.")
+    HDassert(descendants_clean);
+}
 #endif /* NDEBUG */
 
-        /* Check for needing to re-allocate indirect block from 'temp.' to 'normal' file space */
-        if(H5F_IS_TMP_ADDR(f, addr)) {
-            /* Sanity check */
-            HDassert(H5F_addr_eq(iblock->addr, addr));
+    /* Check to see if we must re-allocate the iblock from temporary to 
+     * normal (AKA real) file space.
+     */
+    if(H5F_IS_TMP_ADDR(f, addr)) {
+        haddr_t iblock_addr;
 
-            /* Allocate 'normal' space for the new indirect block on disk */
-            if(HADDR_UNDEF == (addr = H5MF_alloc(f, H5FD_MEM_FHEAP_IBLOCK, dxpl_id, (hsize_t)iblock->size)))
-                HGOTO_ERROR(H5E_HEAP, H5E_NOSPACE, FAIL, "file allocation failed for fractal heap indirect block")
+        /* Allocate 'normal' space for the new indirect block on disk */
+        if(HADDR_UNDEF == (iblock_addr = H5MF_alloc((H5F_t *)f, H5FD_MEM_FHEAP_IBLOCK, dxpl_id, (hsize_t)iblock->size)))
+            HGOTO_ERROR(H5E_HEAP, H5E_NOSPACE, FAIL, "file allocation failed for fractal heap indirect block")
 
-            /* Sanity check */
-            HDassert(!H5F_addr_eq(iblock->addr, addr));
+        /* Sanity check */
+        HDassert(!H5F_addr_eq(iblock->addr, iblock_addr));
 
-            /* Let the metadata cache know the block moved */
-            if(H5AC_move_entry(f, H5AC_FHEAP_IBLOCK, iblock->addr, addr) < 0)
-                HGOTO_ERROR(H5E_HEAP, H5E_CANTMOVE, FAIL, "unable to move indirect block")
+        /* Let the metadata cache know the block moved */
+        if(H5AC_move_entry((H5F_t *)f, H5AC_FHEAP_IBLOCK, iblock->addr, iblock_addr) < 0)
+            HGOTO_ERROR(H5E_HEAP, H5E_CANTMOVE, FAIL, "unable to move indirect block")
 
-            /* Update the internal address for the block */
-            iblock->addr = addr;
+        /* Update the internal address for the block */
+        iblock->addr = iblock_addr;
 
-            /* Check for root indirect block */
-            if(NULL == iblock->parent) {
-                /* Update information about indirect block's location */
-                hdr->man_dtable.table_addr = addr;
+        /* Check for root indirect block */
+        if(NULL == iblock->parent) {
+            /* Update information about indirect block's location */
+            hdr->man_dtable.table_addr = iblock_addr;
 
-                /* Mark that heap header was modified */
-                if(H5HF_hdr_dirty(hdr) < 0)
-                    HGOTO_ERROR(H5E_HEAP, H5E_CANTDIRTY, FAIL, "can't mark heap header as dirty")
-            } /* end if */
-            else {
-                H5HF_indirect_t *par_iblock;    /* Parent indirect block */
-                unsigned par_entry;             /* Entry in parent indirect block */
+            /* Mark that heap header was modified */
+            if(H5HF_hdr_dirty(hdr) < 0)
+                HGOTO_ERROR(H5E_HEAP, H5E_CANTDIRTY, FAIL, "can't mark heap header as dirty")
+        } /* end if */
+        else {
+            H5HF_indirect_t *par_iblock;    /* Parent indirect block */
+            unsigned par_entry;             /* Entry in parent indirect block */
 
-                /* Get parent information */
-                par_iblock = iblock->parent;
-                par_entry = iblock->par_entry;
+            /* Get parent information */
+            par_iblock = iblock->parent;
+            par_entry = iblock->par_entry;
 
-                /* Update information about indirect block's location */
-                par_iblock->ents[par_entry].addr = addr;
+            /* Update information about indirect block's location */
+            par_iblock->ents[par_entry].addr = iblock_addr;
 
-                /* Mark that parent was modified */
-                if(H5HF_iblock_dirty(par_iblock) < 0)
-                    HGOTO_ERROR(H5E_HEAP, H5E_CANTDIRTY, FAIL, "can't mark heap header as dirty")
-            } /* end if */
+            /* Mark that parent was modified */
+            if(H5HF_iblock_dirty(par_iblock) < 0)
+                HGOTO_ERROR(H5E_HEAP, H5E_CANTDIRTY, FAIL, "can't mark heap header as dirty")
         } /* end if */
 
-        /* Indirect block must be in 'normal' file space now */
-        HDassert(!H5F_IS_TMP_ADDR(f, addr));
-
-	/* Write the indirect block */
-	if(H5F_block_write(f, H5FD_MEM_FHEAP_IBLOCK, addr, iblock->size, dxpl_id, buf) < 0)
-	    HGOTO_ERROR(H5E_HEAP, H5E_CANTFLUSH, FAIL, "unable to save fractal heap indirect block to disk")
-
-        /* Reset dirty flags */
-	iblock->cache_info.is_dirty = FALSE;
+	*new_addr = iblock_addr;
+        *flags = H5C__SERIALIZE_MOVED_FLAG;
     } /* end if */
-
-    if(destroy)
-        if(H5HF_cache_iblock_dest(f, iblock) < 0)
-	    HGOTO_ERROR(H5E_HEAP, H5E_CANTFREE, FAIL, "unable to destroy fractal heap indirect block")
+    else 
+	*flags = 0;
 
 done:
-    /* Release resources */
-    if(wb && H5WB_unwrap(wb) < 0)
-        HDONE_ERROR(H5E_HEAP, H5E_CLOSEERROR, FAIL, "can't close wrapped buffer")
-
     FUNC_LEAVE_NOAPI(ret_value)
-} /* H5HF_cache_iblock_flush() */
+} /* end H5HF__cache_iblock_pre_serialize() */
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5HF_cache_iblock_dest
+ * Function:	H5HF__cache_iblock_serialize
  *
- * Purpose:	Destroys a fractal heap indirect block in memory.
+ * Purpose:	Given a pointer to an iblock, and a pointer to a buffer of 
+ *		the appropriate size, write the contents of the iblock to the 
+ *		buffer in format appropriate for writing to disk.
  *
- * Return:	Non-negative on success/Negative on failure
+ * Return:	Success:	SUCCEED
+ *		Failure:	FAIL
  *
- * Programmer:	Quincey Koziol
- *		koziol@ncsa.uiuc.edu
- *		Mar  6 2006
+ * Programmer:	John Mainzer
+ *		6/21/14
  *
  *-------------------------------------------------------------------------
  */
-static herr_t
-H5HF_cache_iblock_dest(H5F_t *f, H5HF_indirect_t *iblock)
+static herr_t 
+H5HF__cache_iblock_serialize(const H5F_t *f, void *_image, size_t len,
+    void *_thing)
 {
-    herr_t      ret_value = SUCCEED;    /* Return value */
+    H5HF_hdr_t 		*hdr;           /* Shared fractal heap information */
+    H5HF_indirect_t     *iblock = (H5HF_indirect_t *)_thing;     /* Indirect block info */
+    uint8_t 		*image = (uint8_t *)_image;     /* Pointer into raw data buffer */
+#ifndef NDEBUG
+    unsigned 		 nchildren = 0; /* Track # of children */
+    size_t		 max_child = 0; /* Track max. child entry used */
+#endif /* NDEBUG */
+    uint32_t		 metadata_chksum; /* Computed metadata checksum value */
+    size_t 		 u;             /* Local index variable */
+    herr_t               ret_value = SUCCEED;    /* Return value */
 
-    FUNC_ENTER_NOAPI_NOINIT
+    FUNC_ENTER_STATIC_NOERR
 
-    /*
-     * Check arguments.
-     */
+    /* Sanity checks */
+    HDassert(f);
+    HDassert(image);
     HDassert(iblock);
-    HDassert(iblock->rc == 0);
-    HDassert(iblock->hdr);
+    HDassert(iblock->cache_info.magic == H5C__H5C_CACHE_ENTRY_T_MAGIC);
+    HDassert(iblock->cache_info.type == H5AC_FHEAP_IBLOCK);
+    HDassert(iblock->cache_info.size == iblock->size);
+    HDassert(len == iblock->size);
 
-    /* If we're going to free the space on disk, the address must be valid */
-    HDassert(!iblock->cache_info.free_file_space_on_destroy || H5F_addr_defined(iblock->cache_info.addr));
-
-    /* Check for freeing file space for indirect block */
-    if(iblock->cache_info.free_file_space_on_destroy) {
-        /* Check if the indirect block is NOT currently allocated in temp. file space */
-        /* (temp. file space does not need to be freed) */
-        if(!H5F_IS_TMP_ADDR(f, iblock->cache_info.addr)) {
-            /* Release the space on disk */
-            /* (XXX: Nasty usage of internal DXPL value! -QAK) */
-            if(H5MF_xfree(f, H5FD_MEM_FHEAP_IBLOCK, H5AC_dxpl_id, iblock->cache_info.addr, (hsize_t)iblock->size) < 0)
-                HGOTO_ERROR(H5E_HEAP, H5E_CANTFREE, FAIL, "unable to free fractal heap indirect block")
-        } /* end if */
-    } /* end if */
+    /* Indirect block must be in 'normal' file space */
+    HDassert(!H5F_IS_TMP_ADDR(f, iblock->addr));
+    HDassert(H5F_addr_eq(iblock->addr, iblock->cache_info.addr));
 
-    /* Destroy fractal heap indirect block */
-    if(H5HF_man_iblock_dest(iblock) < 0)
-        HGOTO_ERROR(H5E_HEAP, H5E_CANTFREE, FAIL, "unable to destroy fractal heap indirect block")
+    /* Get the pointer to the shared heap header */
+    hdr = iblock->hdr;
 
-done:
-    FUNC_LEAVE_NOAPI(ret_value)
-} /* end H5HF_cache_iblock_dest() */
+    /* Set the shared heap header's file context for this operation */
+    hdr->f = f;
 
-
-/*-------------------------------------------------------------------------
- * Function:	H5HF_cache_iblock_clear
- *
- * Purpose:	Mark a fractal heap indirect block in memory as non-dirty.
- *
- * Return:	Non-negative on success/Negative on failure
- *
- * Programmer:	Quincey Koziol
- *		koziol@ncsa.uiuc.edu
- *		Mar  6 2006
- *
- *-------------------------------------------------------------------------
- */
-static herr_t
-H5HF_cache_iblock_clear(H5F_t *f, H5HF_indirect_t *iblock, hbool_t destroy)
-{
-    herr_t ret_value = SUCCEED;         /* Return value */
+    /* Magic number */
+    HDmemcpy(image, H5HF_IBLOCK_MAGIC, (size_t)H5_SIZEOF_MAGIC);
+    image += H5_SIZEOF_MAGIC;
 
-    FUNC_ENTER_NOAPI_NOINIT
+    /* Version # */
+    *image++ = H5HF_IBLOCK_VERSION;
 
-    /*
-     * Check arguments.
-     */
-    HDassert(iblock);
+    /* Address of heap header for heap which owns this block */
+    H5F_addr_encode(f, &image, hdr->heap_addr);
 
-    /* Reset the dirty flag.  */
-    iblock->cache_info.is_dirty = FALSE;
+    /* Offset of block in heap */
+    UINT64ENCODE_VAR(image, iblock->block_off, hdr->heap_off_size);
 
-    if(destroy)
-        if(H5HF_cache_iblock_dest(f, iblock) < 0)
-	    HGOTO_ERROR(H5E_HEAP, H5E_CANTFREE, FAIL, "unable to destroy fractal heap indirect block")
+    /* Encode indirect block-specific fields */
+    for(u = 0; u < (iblock->nrows * hdr->man_dtable.cparam.width); u++) {
+        /* Encode child block address */
+        H5F_addr_encode(f, &image, iblock->ents[u].addr);
+
+        /* Check for heap with I/O filters */
+        if(hdr->filter_len > 0) {
+            /* Sanity check */
+            HDassert(iblock->filt_ents);
+
+            /* Encode extra information for direct blocks */
+            if(u < (hdr->man_dtable.max_direct_rows * hdr->man_dtable.cparam.width)) {
+                /* Sanity check */
+                /* (either both the address & size are defined or both are
+                 *  not defined)
+                 */
+                HDassert((H5F_addr_defined(iblock->ents[u].addr) && iblock->filt_ents[u].size) 
+                        || (!H5F_addr_defined(iblock->ents[u].addr) && iblock->filt_ents[u].size == 0));
+
+                /* Size of filtered direct block */
+                H5F_ENCODE_LENGTH(f, image, iblock->filt_ents[u].size);
+
+                /* I/O filter mask for filtered direct block */
+                UINT32ENCODE(image, iblock->filt_ents[u].filter_mask);
+            } /* end if */
+        } /* end if */
+
+#ifndef NDEBUG
+        /* Count child blocks */
+        if(H5F_addr_defined(iblock->ents[u].addr)) {
+            nchildren++;
+            if(u > max_child)
+                max_child = u;
+        } /* end if */
+#endif /* NDEBUG */
+    } /* end for */
+
+    /* Compute checksum */
+    metadata_chksum = H5_checksum_metadata((uint8_t *)_image, (size_t)(image - (uint8_t *)_image), 0);
+
+    /* Metadata checksum */
+    UINT32ENCODE(image, metadata_chksum);
+
+    /* Sanity checks */
+    HDassert((size_t)(image - (uint8_t *)_image) == iblock->size);
+#ifndef NDEBUG
+    HDassert(nchildren == iblock->nchildren);
+    HDassert(max_child == iblock->max_child);
+#endif /* NDEBUG */
 
-done:
     FUNC_LEAVE_NOAPI(ret_value)
-} /* end H5HF_cache_iblock_clear() */
+} /* end H5HF__cache_iblock_serialize() */
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5HF_cache_iblock_notify
+ * Function:	H5HF__cache_iblock_notify
  *
- * Purpose:	Setup / takedown flush dependencies as indirect blocks
+ * Purpose:	This function is used to create and destroy flush dependency 
+ *		relationships between iblocks and their parents as indirect blocks
  *		are loaded / inserted and evicted from the metadata cache.
  *
- * Return:	Non-negative on success/Negative on failure
+ *		In general, the parent will be another iblock, but it may be the 
+ *		header if the iblock in question is the root iblock.
+ *
+ * Return:	Success:	SUCCEED
+ *		Failure:	FAIL
  *
  * Programmer:	John Mainzer
- *		5/17/14
+ *		6/21/14
  *
  *-------------------------------------------------------------------------
  */
-static herr_t
-H5HF_cache_iblock_notify(H5C_notify_action_t action, H5HF_indirect_t *iblock)
+static herr_t 
+H5HF__cache_iblock_notify(H5C_notify_action_t action, void *_thing)
 {
-    herr_t ret_value = SUCCEED;         /* Return value */
+    H5HF_indirect_t     *iblock = (H5HF_indirect_t *)_thing;    /* Indirect block info */
+    herr_t      	 ret_value = SUCCEED;    /* Return value */
 
-    FUNC_ENTER_NOAPI_NOINIT
+    FUNC_ENTER_STATIC
 
-    /*
-     * Check arguments.
-     */
+    /* Sanity checks */
     HDassert(iblock);
     HDassert(iblock->cache_info.magic == H5C__H5C_CACHE_ENTRY_T_MAGIC);
+    HDassert(iblock->cache_info.type == H5AC_FHEAP_IBLOCK);
     HDassert(iblock->hdr);
 
     if(action == H5AC_NOTIFY_ACTION_BEFORE_EVICT)
@@ -1309,6 +1419,7 @@ H5HF_cache_iblock_notify(H5C_notify_action_t action, H5HF_indirect_t *iblock)
 
     switch(action) {
         case H5AC_NOTIFY_ACTION_AFTER_INSERT:
+        case H5AC_NOTIFY_ACTION_AFTER_LOAD:
             if(iblock->parent) {        /* this is a child iblock */
                 /* create flush dependency with parent iblock */
                 if(H5AC_create_flush_dependency(iblock->parent, iblock) < 0)
@@ -1321,6 +1432,10 @@ H5HF_cache_iblock_notify(H5C_notify_action_t action, H5HF_indirect_t *iblock)
             } /* end else */
             break;
 
+	case H5AC_NOTIFY_ACTION_AFTER_FLUSH:
+	    /* do nothing */
+	    break;
+
         case H5AC_NOTIFY_ACTION_BEFORE_EVICT:
             if(iblock->fd_parent) {     /* this is a child iblock */
                 /* destroy flush dependency with parent iblock */
@@ -1341,38 +1456,104 @@ H5HF_cache_iblock_notify(H5C_notify_action_t action, H5HF_indirect_t *iblock)
 
 done:
     FUNC_LEAVE_NOAPI(ret_value)
-} /* end H5HF_cache_iblock_notify() */
+} /* end H5HF__cache_iblock_notify() */
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5HF_cache_iblock_size
+ * Function:	H5HF__cache_iblock_free_icr
  *
- * Purpose:	Compute the size in bytes of a fractal heap indirect block
- *		on disk, and return it in *size_ptr.  On failure,
- *		the value of *size_ptr is undefined.
+ * Purpose:	Unlink the supplied instance of H5HF_indirect_t from the 
+ *		fractal heap and free its memory.
  *
- * Return:	Non-negative on success/Negative on failure
+ * Note:	The metadata cache sets the object's cache_info.magic to
+ *		H5C__H5C_CACHE_ENTRY_T_BAD_MAGIC before calling a free_icr
+ *		callback (checked in assert).
  *
- * Programmer:	Quincey Koziol
- *		koziol@ncsa.uiuc.edu
- *		Mar  6 2006
+ * Return:	Success:	SUCCEED
+ *		Failure:	FAIL
+ *
+ * Programmer:	John Mainzer
+ *		6/21/14
  *
  *-------------------------------------------------------------------------
  */
-static herr_t
-H5HF_cache_iblock_size(const H5F_t H5_ATTR_UNUSED *f, const H5HF_indirect_t *iblock, size_t *size_ptr)
+static herr_t 
+H5HF__cache_iblock_free_icr(void *thing)
 {
-    FUNC_ENTER_NOAPI_NOINIT_NOERR
+    H5HF_indirect_t	*iblock = (H5HF_indirect_t *)thing;     /* Fractal heap indirect block to free */
+    herr_t      	 ret_value = SUCCEED;    /* Return value */
 
-    /* Check arguments */
+    FUNC_ENTER_STATIC
+
+    /* Sanity checks */
     HDassert(iblock);
-    HDassert(size_ptr);
+    HDassert(iblock->cache_info.magic == H5C__H5C_CACHE_ENTRY_T_BAD_MAGIC);
+    HDassert(iblock->cache_info.type == H5AC_FHEAP_IBLOCK);
+    HDassert(iblock->rc == 0);
+    HDassert(iblock->hdr);
+
+    /* Destroy fractal heap indirect block */
+    if(H5HF_man_iblock_dest(iblock) < 0)
+        HGOTO_ERROR(H5E_HEAP, H5E_CANTFREE, FAIL, "unable to destroy fractal heap indirect block")
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5HF__cache_iblock_free_icr() */
+
+/*********************************************************/
+/* metadata cache callback definitions for direct blocks */
+/*********************************************************/
+
+
+/*-------------------------------------------------------------------------
+ * Function:	H5HF__cache_dblock_get_load_size()
+ *
+ * Purpose:	Determine the size of the direct block on disk image, and 
+ *		return it in *image_len.
+ *
+ * Return:	Success:	SUCCEED
+ *		Failure:	FAIL
+ *
+ * Programmer:	John Mainzer
+ *		6/21/14
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t 
+H5HF__cache_dblock_get_load_size(const void *_udata, size_t *image_len)
+{
+    const H5HF_dblock_cache_ud_t *udata = (const H5HF_dblock_cache_ud_t *)_udata;    /* User data for callback */
+    const H5HF_parent_t         *par_info; /* Pointer to parent information */
+    const H5HF_hdr_t            *hdr;     /* Shared fractal heap information */
+    size_t                      size;
+
+    FUNC_ENTER_STATIC_NOERR
+
+    /* Sanity checks */
+    HDassert(udata);
+    HDassert(image_len);
+    par_info = (const H5HF_parent_t *)(&(udata->par_info));
+    HDassert(par_info);
+    hdr = par_info->hdr;
+    HDassert(hdr);
+    HDassert(hdr->cache_info.magic == H5C__H5C_CACHE_ENTRY_T_MAGIC);
+    HDassert(hdr->cache_info.type == H5AC_FHEAP_HDR);
+
+    /* Check for I/O filters on this heap */
+    if(hdr->filter_len > 0) {
+        /* Check for root direct block */
+        if(par_info->iblock == NULL)
+            size = hdr->pline_root_direct_size;
+        else
+            size = par_info->iblock->filt_ents[par_info->entry].size;
+    } /* end if */
+    else
+        size = udata->dblock_size;
 
-    /* Set size value */
-    *size_ptr = iblock->size;
+    *image_len = size;
 
     FUNC_LEAVE_NOAPI(SUCCEED)
-} /* H5HF_cache_iblock_size() */
+} /* end H5HF__cache_dblock_get_load_size() */
 
 /*********************************************************/
 /* metadata cache callback definitions for direct blocks */
@@ -1380,49 +1561,55 @@ H5HF_cache_iblock_size(const H5F_t H5_ATTR_UNUSED *f, const H5HF_indirect_t *ibl
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5HF_cache_dblock_load
+ * Function:	H5HF__cache_dblock_deserialize
  *
- * Purpose:	Loads a fractal heap direct block from the disk.
+ * Purpose:	Given a buffer containing the on disk image of a direct
+ *		block, allocate an instance of H5HF_direct_t, load the data
+ *		in the buffer into this new instance, and return a pointer to
+ *		it.
  *
- * Return:	Success:	Pointer to a new fractal heap direct block
+ *		As best I can tell, the size of the direct block image is fully
+ *		know before the image is loaded, so this function should succeed
+ *		unless the image is corrupt or memory allocation fails.
  *
+ * Return:	Success:	Pointer to in core representation
  *		Failure:	NULL
  *
- * Programmer:	Quincey Koziol
- *		koziol@ncsa.uiuc.edu
- *		Feb 27 2006
+ * Programmer:	John Mainzer
+ *		6/21/14
  *
  *-------------------------------------------------------------------------
  */
-static H5HF_direct_t *
-H5HF_cache_dblock_load(H5F_t *f, hid_t dxpl_id, haddr_t addr, void *_udata)
+static void *
+H5HF__cache_dblock_deserialize(const void *_image, size_t len, void *_udata,
+    hbool_t H5_ATTR_UNUSED *dirty)
 {
     H5HF_hdr_t          *hdr;           /* Shared fractal heap information */
     H5HF_dblock_cache_ud_t *udata = (H5HF_dblock_cache_ud_t *)_udata;   /* User data for callback */
     H5HF_parent_t       *par_info;      /* Pointer to parent information */
-    H5HF_direct_t	*dblock = NULL; /* Direct block info */
-    const uint8_t	*p;             /* Pointer into raw data buffer */
+    H5HF_direct_t       *dblock = NULL; /* Direct block info */
+    const uint8_t       *image;         /* Pointer into raw data buffer */
     haddr_t             heap_addr;      /* Address of heap header in the file */
-    H5HF_direct_t	*ret_value;     /* Return value */
+    void *              ret_value;      /* Return value */
 
-    FUNC_ENTER_NOAPI_NOINIT
+    FUNC_ENTER_STATIC
 
-    /* Check arguments */
-    HDassert(f);
-    HDassert(H5F_addr_defined(addr));
-    HDassert(udata != NULL);
-    HDassert(udata->f != NULL);
-    HDassert(udata->dblock_size > 0);
+    /* Sanity checks */
+    HDassert(_image);
+    HDassert(udata);
+    par_info = (H5HF_parent_t *)(&(udata->par_info));
+    HDassert(par_info);
+    hdr = par_info->hdr;
+    HDassert(hdr);
+    HDassert(hdr->cache_info.magic == H5C__H5C_CACHE_ENTRY_T_MAGIC);
+    HDassert(hdr->cache_info.type == H5AC_FHEAP_HDR);
+    HDassert(dirty);
 
     /* Allocate space for the fractal heap direct block */
     if(NULL == (dblock = H5FL_MALLOC(H5HF_direct_t)))
         HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, NULL, "memory allocation failed")
     HDmemset(&dblock->cache_info, 0, sizeof(H5AC_info_t));
 
-    /* Get the pointer to the shared heap header */
-    par_info = (H5HF_parent_t *)(&(udata->par_info));
-    hdr = par_info->hdr;
-
     /* Set the shared heap header's file context for this operation */
     hdr->f = udata->f;
 
@@ -1435,6 +1622,10 @@ H5HF_cache_dblock_load(H5F_t *f, hid_t dxpl_id, haddr_t addr, void *_udata)
     dblock->size = udata->dblock_size;
     dblock->file_size = 0;
 
+    /* initialize fields used in serialization */
+    dblock->write_buf = NULL;
+    dblock->write_size = 0;
+
     /* Allocate block buffer */
 /* XXX: Change to using free-list factories */
     if(NULL == (dblock->blk = H5FL_BLK_MALLOC(direct_block, (size_t)dblock->size)))
@@ -1449,28 +1640,21 @@ H5HF_cache_dblock_load(H5F_t *f, hid_t dxpl_id, haddr_t addr, void *_udata)
         unsigned filter_mask;   /* Excluded filters for direct block */
 
         /* Check for root direct block */
-        if(par_info->iblock == NULL) {
-            /* Sanity check */
-            HDassert(H5F_addr_eq(hdr->man_dtable.table_addr, addr));
-
+        if(par_info->iblock == NULL)
             /* Set up parameters to read filtered direct block */
             read_size = hdr->pline_root_direct_size;
-        } /* end if */
-        else {
-            /* Sanity check */
-            HDassert(H5F_addr_eq(par_info->iblock->ents[par_info->entry].addr, addr));
-
+        else
             /* Set up parameters to read filtered direct block */
             read_size = par_info->iblock->filt_ents[par_info->entry].size;
-        } /* end else */
+        HDassert(len == read_size);
 
-        /* Allocate buffer to perform I/O filtering on */
+        /* Allocate buffer to perform I/O filtering on and copy image into
+         * it.  Must do this as H5Z_pipeline() may re-sized the buffer 
+         * provided to it.
+         */
         if(NULL == (read_buf = H5MM_malloc(read_size)))
             HGOTO_ERROR(H5E_HEAP, H5E_NOSPACE, NULL, "memory allocation failed for pipeline buffer")
-
-        /* Read filtered direct block from disk */
-        if(H5F_block_read(f, H5FD_MEM_FHEAP_DBLOCK, addr, read_size, dxpl_id, read_buf) < 0)
-            HGOTO_ERROR(H5E_HEAP, H5E_READERROR, NULL, "can't read fractal heap direct block")
+        HDmemcpy(read_buf, _image, len);
 
         /* Push direct block data through I/O filter pipeline */
         nbytes = read_size;
@@ -1488,25 +1672,25 @@ H5HF_cache_dblock_load(H5F_t *f, hid_t dxpl_id, haddr_t addr, void *_udata)
         H5MM_xfree(read_buf);
     } /* end if */
     else {
-        /* Read direct block from disk */
-        if(H5F_block_read(f, H5FD_MEM_FHEAP_DBLOCK, addr, dblock->size, dxpl_id, dblock->blk) < 0)
-            HGOTO_ERROR(H5E_HEAP, H5E_READERROR, NULL, "can't read fractal heap direct block")
+        /* copy image to dblock->blk */
+        HDassert(dblock->size == len);
+        HDmemcpy(dblock->blk, _image, dblock->size);
     } /* end else */
 
     /* Start decoding direct block */
-    p = dblock->blk;
+    image = dblock->blk;
 
     /* Magic number */
-    if(HDmemcmp(p, H5HF_DBLOCK_MAGIC, (size_t)H5_SIZEOF_MAGIC))
-        HGOTO_ERROR(H5E_HEAP, H5E_CANTLOAD, NULL, "wrong fractal heap direct block signature")
-    p += H5_SIZEOF_MAGIC;
+    if(HDmemcmp(image, H5HF_DBLOCK_MAGIC, (size_t)H5_SIZEOF_MAGIC))
+        HGOTO_ERROR(H5E_HEAP, H5E_BADVALUE, NULL, "wrong fractal heap direct block signature")
+    image += H5_SIZEOF_MAGIC;
 
     /* Version */
-    if(*p++ != H5HF_DBLOCK_VERSION)
+    if(*image++ != H5HF_DBLOCK_VERSION)
         HGOTO_ERROR(H5E_HEAP, H5E_VERSION, NULL, "wrong fractal heap direct block version")
 
     /* Address of heap that owns this block (just for file integrity checks) */
-    H5F_addr_decode(udata->f, &p, &heap_addr);
+    H5F_addr_decode(udata->f, &image, &heap_addr);
     if(H5F_addr_ne(heap_addr, hdr->heap_addr))
         HGOTO_ERROR(H5E_HEAP, H5E_CANTLOAD, NULL, "incorrect heap header address for direct block")
 
@@ -1521,7 +1705,7 @@ H5HF_cache_dblock_load(H5F_t *f, hid_t dxpl_id, haddr_t addr, void *_udata)
     } /* end if */
 
     /* Offset of heap within the heap's address space */
-    UINT64DECODE_VAR(p, dblock->block_off, hdr->heap_off_size);
+    UINT64DECODE_VAR(image, dblock->block_off, hdr->heap_off_size);
 
     /* Decode checksum on direct block, if requested */
     if(hdr->checksum_dblocks) {
@@ -1529,11 +1713,11 @@ H5HF_cache_dblock_load(H5F_t *f, hid_t dxpl_id, haddr_t addr, void *_udata)
         uint32_t computed_chksum;       /* Computed metadata checksum value */
 
         /* Metadata checksum */
-        UINT32DECODE(p, stored_chksum);
+        UINT32DECODE(image, stored_chksum);
 
         /* Reset checksum field, for computing the checksum */
         /* (Casting away const OK - QAK) */
-        HDmemset((uint8_t *)p - H5HF_SIZEOF_CHKSUM, 0, (size_t)H5HF_SIZEOF_CHKSUM);
+        HDmemset((uint8_t *)image - H5HF_SIZEOF_CHKSUM, 0, (size_t)H5HF_SIZEOF_CHKSUM);
 
         /* Compute checksum on entire direct block */
         computed_chksum = H5_checksum_metadata(dblock->blk, dblock->size, 0);
@@ -1544,10 +1728,10 @@ H5HF_cache_dblock_load(H5F_t *f, hid_t dxpl_id, haddr_t addr, void *_udata)
     } /* end if */
 
     /* Sanity check */
-    HDassert((size_t)(p - dblock->blk) == (size_t)H5HF_MAN_ABS_DIRECT_OVERHEAD(hdr));
+    HDassert((size_t)(image - dblock->blk) == (size_t)H5HF_MAN_ABS_DIRECT_OVERHEAD(hdr));
 
     /* Set return value */
-    ret_value = dblock;
+    ret_value = (void *)dblock;
 
 done:
     if(!ret_value && dblock)
@@ -1555,402 +1739,646 @@ done:
             HDONE_ERROR(H5E_HEAP, H5E_CANTFREE, NULL, "unable to destroy fractal heap direct block")
 
     FUNC_LEAVE_NOAPI(ret_value)
-} /* end H5HF_cache_dblock_load() */
+} /* end H5HF__cache_dblock_deserialize() */
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5HF_cache_dblock_flush
+ * Function:	H5HF__cache_dblock_image_len
  *
- * Purpose:	Flushes a dirty fractal heap direct block to disk.
+ * Purpose:	Report the actual size of the direct block image on disk.
+ *		Note that this value will probably be incorrect if compression 
+ *		is enabled and the entry is dirty.
  *
- * Return:	Non-negative on success/Negative on failure
+ * Return:	Success:	SUCCEED
+ *		Failure:	FAIL
  *
- * Programmer:	Quincey Koziol
- *		koziol@ncsa.uiuc.edu
- *		Feb 27 2006
+ * Programmer:	John Mainzer
+ *		6/21/14
  *
  *-------------------------------------------------------------------------
  */
-static herr_t
-H5HF_cache_dblock_flush(H5F_t *f, hid_t dxpl_id, hbool_t destroy, haddr_t addr, H5HF_direct_t *dblock, unsigned H5_ATTR_UNUSED * flags_ptr)
+static herr_t 
+H5HF__cache_dblock_image_len(const void *_thing, size_t *image_len, hbool_t *compressed_ptr, size_t *compressed_image_len_ptr)
 {
-    herr_t      ret_value = SUCCEED;    /* Return value */
+    const H5HF_direct_t    *dblock = (const H5HF_direct_t *)_thing;     /* Direct block info */
+    const H5HF_indirect_t  *par_iblock; /* Parent iblock */
+    const H5HF_hdr_t  *hdr;             /* Shared fractal heap information */
+    hbool_t	      compressed;
+    size_t            size;
+    size_t	      compressed_size;
 
-    FUNC_ENTER_NOAPI_NOINIT
+    FUNC_ENTER_STATIC_NOERR
 
-    /* check arguments */
-    HDassert(f);
-    HDassert(H5F_addr_defined(addr));
+    /* Sanity checks */
     HDassert(dblock);
+    HDassert(dblock->cache_info.magic == H5C__H5C_CACHE_ENTRY_T_MAGIC);
+    HDassert(dblock->cache_info.type == H5AC_FHEAP_DBLOCK);
+    HDassert(image_len);
+    HDassert(compressed_ptr);
+    HDassert(compressed_image_len_ptr);
 
-    if(dblock->cache_info.is_dirty) {
-        H5HF_hdr_t *hdr;        /* Shared fractal heap information */
-        hbool_t at_tmp_addr = H5F_IS_TMP_ADDR(f, addr);     /* Flag to indicate direct block is at temporary address */
-        void *write_buf;        /* Pointer to buffer to write out */
-        size_t write_size;      /* Size of buffer to write out */
-        uint8_t *p;             /* Pointer into raw data buffer */
+    /* Set up convenience variables */
+    hdr = dblock->hdr;
+    par_iblock = dblock->parent;
 
-        /* Get the pointer to the shared heap header */
-        hdr = dblock->hdr;
+    /* Check for I/O filters on this heap */
+    if(hdr->filter_len > 0) {
 
-        /* Set the shared heap header's file context for this operation */
-        hdr->f = f;
+        /* Filters are enabled, so set compressed to TRUE, and set 
+ 	 * size equal to the uncompressed size of the direct block.
+         * If the data is available, set compressed_size to the compressed
+         * size of the direct block -- otherwise set it equal to the 
+         * uncompressed size.  
+         *
+         * We have three possible scenarios here.
+         *
+         * First, the block may never have been flushed.  In this
+         * case, both dblock->file_size and the size stored in the 
+         * parent (either the header or the parent iblock) will all 
+         * be zero.  In this case, return the uncompressed size 
+         * stored in dblock->size as the compressed size.
+         *
+         * Second, the block may have just been serialized, in which
+         * case, dblock->file_size should be zero, and the correct 
+         * on disk size should be stored in the parent (again, either
+         * the header or the parent iblock as case may be).
+         * 
+         * Third, we may be in the process of discarding this 
+         * dblock without writing it.  In this case, dblock->file_size
+         * should be non-zero and have the correct size.  Note that 
+         * in this case, the direct block will have been detached,
+         * and thus looking up the parent will likely return incorrect
+         * data.
+         */
+        size            = dblock->size;
+        compressed      = TRUE;
+        compressed_size = dblock->size; /* will overwrite if compressed 
+                                         * size is available.
+                                         */
+
+        if(dblock->file_size != 0) 
+            compressed_size = dblock->file_size;
+        else {
+            if(par_iblock) {
+                unsigned          par_entry;  /* Entry in parent indirect block */
 
-        HDassert(dblock->blk);
-        p = dblock->blk;
+                par_entry = dblock->par_entry;
+                compressed_size = par_iblock->filt_ents[par_entry].size;
 
-        /* Magic number */
-        HDmemcpy(p, H5HF_DBLOCK_MAGIC, (size_t)H5_SIZEOF_MAGIC);
-        p += H5_SIZEOF_MAGIC;
+            } /* end if */
+            else {
+                compressed_size = hdr->pline_root_direct_size;
+            }
 
-        /* Version # */
-        *p++ = H5HF_DBLOCK_VERSION;
+            if(compressed_size == 0)
+                compressed_size = dblock->size;
 
-        /* Address of heap header for heap which owns this block */
-        H5F_addr_encode(f, &p, hdr->heap_addr);
+        } /* end else */
+    } /* end if */
+    else {
+        size = dblock->size;
+        compressed = FALSE;
+        compressed_size = 0; /* a convenient, invalid value */
+    }
 
-        /* Offset of block in heap */
-        UINT64ENCODE_VAR(p, dblock->block_off, hdr->heap_off_size);
+    HDassert(size > 0);
 
-        /* Metadata checksum */
-        if(hdr->checksum_dblocks) {
-            uint32_t metadata_chksum;       /* Computed metadata checksum value */
+    *image_len                = size;
+    *compressed_ptr           = compressed;
+    *compressed_image_len_ptr = compressed_size;
 
-            /* Clear the checksum field, to compute the checksum */
-            HDmemset(p, 0, (size_t)H5HF_SIZEOF_CHKSUM);
+    FUNC_LEAVE_NOAPI(SUCCEED)
+} /* end H5HF__cache_dblock_image_len() */
 
-            /* Compute checksum on entire direct block */
-            metadata_chksum = H5_checksum_metadata(dblock->blk, dblock->size, 0);
+
+/*-------------------------------------------------------------------------
+ * Function:	H5HF__cache_dblock_pre_serialize
+ *
+ * Purpose:	In principle, the purpose of this function is to determine
+ *		the size and location of the disk image of the target direct 
+ *		block.  In this case, the uncompressed size of the block is
+ *		fixed, but sined the H5C__CLASS_COMPRESSED_FLAG is set, 
+ *		we may need to compute and report the compressed size.
+ *
+ *		This is a bit sticky in the case of a direct block when I/O 
+ *		filters are enabled, as the size of the compressed version
+ *		of the on disk image is not known until the direct block has 
+ *		been run through the filters.  Further, the location of the 
+ *		on disk image may change if the compressed size of the image 
+ *		changes as well.
+ *
+ *		To complicate matters further, the direct block may have been 
+ *		initially allocated in temporary (AKA imaginary) file space. 
+ *		In this case, we must relocate the direct block's on disk 
+ *		image to real file space regardless of whether it has changed 
+ *		size.
+ *
+ *		One simplifying factor is the direct block's "blk" field, 
+ *		which contains a pointer to a buffer which (with the exception
+ *		of a small header) contains the on disk image in uncompressed 
+ *		form.
+ *
+ *		To square this particular circle, this function does 
+ *		everything the serialize function usually does, with the 
+ *		exception of copying the image into the image buffer provided 
+ *		to the serialize function by the metadata cache.  The data to 
+ *		copy is provided to the serialize function in a buffer pointed
+ *		to by the write_buf field.
+ *
+ *		If I/O filters are enabled, on exit, 
+ *		H5HF__cache_dblock_pre_serialize() sets the write_buf field to 
+ *		point to a buffer containing the filtered image of the direct
+ *		block.  The serialize function should free this block, and set
+ *		the write_buf field to NULL after copying it into the image 
+ *		buffer provided by the metadata cache.
+ *
+ *		If I/O filters are not enabled, this function prepares 
+ *		the buffer pointed to by the blk field for copying to the 
+ *		image buffer provided by the metadata cache, and sets the 
+ *		write_buf field equal to the blk field.  In this case, the 
+ *		serialize function should simply set the write_buf field to 
+ *		NULL after copying the direct block image into the image 
+ *		buffer.
+ *
+ *		In both of the above cases, the length of the buffer pointed 
+ *		to by write_buf is provided in the write_len field.  This 
+ *		field must contain 0 on entry to this function, and should 
+ *		be set back to 0 at the end of the serialize function.
+ *
+ * Return:	Success:	SUCCEED
+ *		Failure:	FAIL
+ *
+ * Programmer:	John Mainzer
+ *		6/21/14
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t 
+H5HF__cache_dblock_pre_serialize(const H5F_t *f, hid_t dxpl_id, void *_thing,
+    haddr_t addr, size_t len, size_t compressed_len, haddr_t *new_addr, 
+    size_t H5_ATTR_UNUSED *new_len, size_t *new_compressed_len, unsigned *flags)
+{
+    hbool_t 		 at_tmp_addr;  /* Flag to indicate direct block is */
+                                       /* at temporary address */
+    haddr_t		 dblock_addr;
+    H5HF_hdr_t          *hdr;           /* Shared fractal heap information */
+    H5HF_direct_t       *dblock = (H5HF_direct_t *)_thing;      /* Direct block info */
+    H5HF_indirect_t 	*par_iblock;    /* Parent indirect block */
+    unsigned		 par_entry;     /* Entry in parent indirect block */
+    void 		*write_buf;     /* Pointer to buffer to write out */
+    size_t 		 write_size;    /* Size of buffer to write out */
+    uint8_t 		*image;         /* Pointer into raw data buffer */
+    unsigned		 dblock_flags = 0;
+    herr_t               ret_value = SUCCEED;    /* Return value */
 
-            /* Metadata checksum */
-            UINT32ENCODE(p, metadata_chksum);
-        } /* end if */
+    FUNC_ENTER_STATIC
 
-        /* Sanity check */
-        HDassert((size_t)(p - dblock->blk) == (size_t)H5HF_MAN_ABS_DIRECT_OVERHEAD(hdr));
+    /* Sanity checks */
+    HDassert(f);
+    HDassert(dblock);
+    HDassert(dblock->cache_info.magic == H5C__H5C_CACHE_ENTRY_T_MAGIC);
+    HDassert(dblock->cache_info.type == H5AC_FHEAP_DBLOCK);
+    HDassert(dblock->write_buf == NULL);
+    HDassert(dblock->write_size == 0);
+    HDassert(dblock->cache_info.size == len);
+    HDassert(H5F_addr_defined(addr));
+    HDassert(len == dblock->size);
+    HDassert(new_addr);
+    HDassert(new_compressed_len);
+    HDassert(flags);
 
-        /* Check for I/O filters on this heap */
-        if(hdr->filter_len > 0) {
-            H5Z_cb_t filter_cb = {NULL, NULL};  /* Filter callback structure */
-            size_t nbytes;                      /* Number of bytes used */
-            unsigned filter_mask = 0;           /* Filter mask for block */
+    /* Set up local variables */
+    hdr = dblock->hdr;
+    dblock_addr = addr;    /* will update dblock_addr if we move the block */
 
-            /* Allocate buffer to perform I/O filtering on */
-            write_size = dblock->size;
-            if(NULL == (write_buf = H5MM_malloc(write_size)))
-                HGOTO_ERROR(H5E_HEAP, H5E_NOSPACE, FAIL, "memory allocation failed for pipeline buffer")
-            HDmemcpy(write_buf, dblock->blk, write_size);
+    /* dblock->size must match dblock->cache_info.size */
+    HDassert(dblock->cache_info.size == dblock->size);
 
-            /* Push direct block data through I/O filter pipeline */
-            nbytes = write_size;
-            if(H5Z_pipeline(&(hdr->pline), 0, &filter_mask, H5Z_ENABLE_EDC, filter_cb, &nbytes, &write_size, &write_buf) < 0)
-                HGOTO_ERROR(H5E_HEAP, H5E_WRITEERROR, FAIL, "output pipeline failed")
+    /* Set the shared heap header's file context for this operation */
+    hdr->f = (H5F_t *)f;
 
-            /* Use the compressed number of bytes as the size to write */
-            write_size = nbytes;
+    HDassert(hdr);
+    HDassert(hdr->cache_info.magic == H5C__H5C_CACHE_ENTRY_T_MAGIC);
+    HDassert(hdr->cache_info.type == H5AC_FHEAP_HDR);
 
-            /* Check for root direct block */
-            if(dblock->parent == NULL) {
-                hbool_t hdr_changed = FALSE;    /* Whether the header information changed */
+    if(dblock->parent) {
+	/* this is the common case, in which the direct block is the child 
+         * of an indirect block.  Set up the convenience variables we will
+         * need if the address and/or compressed size of the on disk image 
+         * of the direct block changes, and do some sanity checking in 
+         * passing.
+         */
+        par_iblock = dblock->parent;
+	par_entry = dblock->par_entry;
 
-                /* Sanity check */
-                HDassert(H5F_addr_eq(hdr->man_dtable.table_addr, addr));
-                HDassert(hdr->pline_root_direct_size > 0);
+	HDassert(par_iblock->cache_info.magic == H5C__H5C_CACHE_ENTRY_T_MAGIC);
+	HDassert(par_iblock->cache_info.type == H5AC_FHEAP_IBLOCK);
+        HDassert(H5F_addr_eq(par_iblock->ents[par_entry].addr, addr));
+    } /* end if */
+    else {
+	/* the direct block is a root direct block -- just set par_iblock
+         * to NULL, as the field will not be used.
+         */
+	par_iblock = NULL;
+    } /* end else */
 
-                /* Check if the filter mask changed */
-                if(hdr->pline_root_direct_filter_mask != filter_mask) {
-                    hdr->pline_root_direct_filter_mask = filter_mask;
-                    hdr_changed = TRUE;
-                } /* end if */
+    at_tmp_addr = H5F_IS_TMP_ADDR(f, addr);
 
-                /* Check if we need to re-size the block on disk */
-                if(hdr->pline_root_direct_size != write_size || at_tmp_addr) {
-                    /* Check if the direct block is NOT currently allocated in temp. file space */
-                    /* (temp. file space does not need to be freed) */
-                    if(!at_tmp_addr) {
-                        /* Release direct block's current disk space */
-                        if(H5MF_xfree(f, H5FD_MEM_FHEAP_DBLOCK, dxpl_id, addr, (hsize_t)hdr->pline_root_direct_size) < 0)
-                            HGOTO_ERROR(H5E_HEAP, H5E_CANTFREE, FAIL, "unable to free fractal heap direct block")
-                    } /* end if */
+    /* Begin by preping the direct block to be written to disk.  Do
+     * this by writing the correct magic number, the dblock version, 
+     * the address of the header, the offset of the block in the heap, 
+     * and the checksum at the beginning of the block.
+     */
 
-                    /* Allocate space for the compressed direct block */
-                    if(HADDR_UNDEF == (addr = H5MF_alloc(f, H5FD_MEM_FHEAP_DBLOCK, dxpl_id, (hsize_t)write_size)))
-                        HGOTO_ERROR(H5E_HEAP, H5E_NOSPACE, FAIL, "file allocation failed for fractal heap direct block")
+    HDassert(dblock->blk);
+    image = dblock->blk;
 
-                    /* Let the metadata cache know, if the block moved */
-                    if(!H5F_addr_eq(hdr->man_dtable.table_addr, addr))
-                        if(H5AC_move_entry(f, H5AC_FHEAP_DBLOCK, hdr->man_dtable.table_addr, addr) < 0)
-                            HGOTO_ERROR(H5E_HEAP, H5E_CANTMOVE, FAIL, "unable to move direct block")
+    /* Magic number */
+    HDmemcpy(image, H5HF_DBLOCK_MAGIC, (size_t)H5_SIZEOF_MAGIC);
+    image += H5_SIZEOF_MAGIC;
 
-                    /* Update information about compressed direct block's location & size */
-                    hdr->man_dtable.table_addr = addr;
-                    hdr->pline_root_direct_size = write_size;
+    /* Version # */
+    *image++ = H5HF_DBLOCK_VERSION;
 
-                    /* Note that heap header was modified */
-                    hdr_changed = TRUE;
-                } /* end if */
+    /* Address of heap header for heap which owns this block */
+    H5F_addr_encode(f, &image, hdr->heap_addr);
 
-                /* Check if heap header was modified */
-                if(hdr_changed)
-                    if(H5HF_hdr_dirty(hdr) < 0)
-                        HGOTO_ERROR(H5E_HEAP, H5E_CANTDIRTY, FAIL, "can't mark heap header as dirty")
-            } /* end if */
-            else {
-                hbool_t par_changed = FALSE;    /* Whether the parent's information changed */
-                H5HF_indirect_t *par_iblock;    /* Parent indirect block */
-                unsigned par_entry;             /* Entry in parent indirect block */
+    /* Offset of block in heap */
+    UINT64ENCODE_VAR(image, dblock->block_off, hdr->heap_off_size);
 
-                /* Get parent information */
-                par_iblock = dblock->parent;
-                par_entry = dblock->par_entry;
+    /* Metadata checksum */
+    if(hdr->checksum_dblocks) {
+        uint32_t metadata_chksum;       /* Computed metadata checksum value */
 
-                /* Sanity check */
-                HDassert(H5F_addr_eq(par_iblock->ents[par_entry].addr, addr));
-                HDassert(par_iblock->filt_ents[par_entry].size > 0);
+        /* Clear the checksum field, to compute the checksum */
+        HDmemset(image, 0, (size_t)H5HF_SIZEOF_CHKSUM);
 
-                /* Check if the filter mask changed */
-                if(par_iblock->filt_ents[par_entry].filter_mask != filter_mask) {
-                    par_iblock->filt_ents[par_entry].filter_mask = filter_mask;
-                    par_changed = TRUE;
-                } /* end if */
+        /* Compute checksum on entire direct block */
+        metadata_chksum = H5_checksum_metadata(dblock->blk, dblock->size, 0);
 
-                /* Check if we need to re-size the block on disk */
-                if(par_iblock->filt_ents[par_entry].size != write_size || at_tmp_addr) {
-                    /* Check if the direct block is NOT currently allocated in temp. file space */
-                    /* (temp. file space does not need to be freed) */
-                    if(!at_tmp_addr) {
-                        /* Release direct block's current disk space */
-                        if(H5MF_xfree(f, H5FD_MEM_FHEAP_DBLOCK, dxpl_id, addr, (hsize_t)par_iblock->filt_ents[par_entry].size) < 0)
-                            HGOTO_ERROR(H5E_HEAP, H5E_CANTFREE, FAIL, "unable to free fractal heap direct block")
-                    } /* end if */
+        /* Metadata checksum */
+        UINT32ENCODE(image, metadata_chksum);
+    } /* end if */
 
-                    /* Allocate space for the compressed direct block */
-                    if(HADDR_UNDEF == (addr = H5MF_alloc(f, H5FD_MEM_FHEAP_DBLOCK, dxpl_id, (hsize_t)write_size)))
-                        HGOTO_ERROR(H5E_HEAP, H5E_NOSPACE, FAIL, "file allocation failed for fractal heap direct block")
+    /* at this point, dblock->blk should point to an uncompressed image of 
+     * the direct block.  If I/O filters are not enabled, this image should
+     * be ready to hand off to the metadata cache.
+     */
 
-                    /* Let the metadata cache know, if the block moved */
-                    if(!H5F_addr_eq(par_iblock->ents[par_entry].addr, addr))
-                        if(H5AC_move_entry(f, H5AC_FHEAP_DBLOCK, par_iblock->ents[par_entry].addr, addr) < 0)
-                            HGOTO_ERROR(H5E_HEAP, H5E_CANTMOVE, FAIL, "unable to move direct block")
+    /* Sanity check */
+    HDassert((size_t)(image - dblock->blk) == (size_t)H5HF_MAN_ABS_DIRECT_OVERHEAD(hdr));
 
-                    /* Update information about compressed direct block's location & size */
-                    par_iblock->ents[par_entry].addr = addr;
-                    par_iblock->filt_ents[par_entry].size = write_size;
+    /* If I/O filters are enabled on this heap, we must run the direct block
+     * image through the filters to obtain the image that we will hand off
+     * to the metadata cache.
+     */
 
-                    /* Note that parent was modified */
-                    par_changed = TRUE;
-                } /* end if */
+    /* Check for I/O filters on this heap */
+    if(hdr->filter_len > 0) {
+        H5Z_cb_t filter_cb = {NULL, NULL};  /* Filter callback structure */
+        size_t nbytes;                      /* Number of bytes used */
+        unsigned filter_mask = 0;           /* Filter mask for block */
 
-                /* Check if parent was modified */
-                if(par_changed)
-                    if(H5HF_iblock_dirty(par_iblock) < 0)
-                        HGOTO_ERROR(H5E_HEAP, H5E_CANTDIRTY, FAIL, "can't mark heap header as dirty")
-            } /* end else */
-        } /* end if */
-        else {
-            write_buf = dblock->blk;
-            write_size = dblock->size;
+        /* Allocate buffer to perform I/O filtering on */
+        write_size = dblock->size;
 
-            /* Check for needing to re-allocate direct block from 'temp.' to 'normal' file space */
-            if(at_tmp_addr) {
-                /* Check for root direct block */
-                if(NULL == dblock->parent) {
-                    /* Sanity check */
-                    HDassert(H5F_addr_eq(hdr->man_dtable.table_addr, addr));
+        if(NULL == (write_buf = H5MM_malloc(write_size)))
+            HGOTO_ERROR(H5E_HEAP, H5E_NOSPACE, FAIL, "memory allocation failed for pipeline buffer")
+        HDmemcpy(write_buf, dblock->blk, write_size);
 
-                    /* Allocate 'normal' space for the direct block */
-                    if(HADDR_UNDEF == (addr = H5MF_alloc(f, H5FD_MEM_FHEAP_DBLOCK, dxpl_id, (hsize_t)write_size)))
-                        HGOTO_ERROR(H5E_HEAP, H5E_NOSPACE, FAIL, "file allocation failed for fractal heap direct block")
+        /* Push direct block data through I/O filter pipeline */
+        nbytes = write_size;
+        if(H5Z_pipeline(&(hdr->pline), 0, &filter_mask, H5Z_ENABLE_EDC, filter_cb, &nbytes, &write_size, &write_buf) < 0)
+            HGOTO_ERROR(H5E_HEAP, H5E_WRITEERROR, FAIL, "output pipeline failed")
+
+        /* Use the compressed number of bytes as the size to write */
+        write_size = nbytes;
+
+        /* If the size and/or location of the on disk image of the 
+         * direct block changes, we must touch up its parent to reflect
+         * these changes.  Do this differently depending on whether the
+         * direct block's parent is an indirect block or (rarely) the 
+         * fractal heap header.  In this case, the direct block is known
+         * as a root direct block.
+         */
 
-                    /* Sanity check */
-                    HDassert(!H5F_addr_eq(hdr->man_dtable.table_addr, addr));
+        /* Check for root direct block */
+        if(dblock->parent == NULL) {
+            hbool_t hdr_changed = FALSE; /* Whether the header info changed */
 
-                    /* Let the metadata cache know the block moved */
-                    if(H5AC_move_entry(f, H5AC_FHEAP_DBLOCK, hdr->man_dtable.table_addr, addr) < 0)
-                        HGOTO_ERROR(H5E_HEAP, H5E_CANTMOVE, FAIL, "unable to move direct block")
+            /* Sanity check */
+            HDassert(H5F_addr_eq(hdr->man_dtable.table_addr, addr));
+            HDassert(hdr->pline_root_direct_size > 0);
 
-                    /* Update information about direct block's location */
-                    hdr->man_dtable.table_addr = addr;
+            /* Check if the filter mask changed */
+            if(hdr->pline_root_direct_filter_mask != filter_mask) {
+                hdr->pline_root_direct_filter_mask = filter_mask;
+                hdr_changed = TRUE;
+            } /* end if */
+
+            /* verify that the cache's last record of the compressed 
+             * size matches the heap's last record.  This value will
+             * likely change shortly.
+             */
+            HDassert(compressed_len == hdr->pline_root_direct_size);
 
-                    /* Mark that heap header was modified */
-                    if(H5HF_hdr_dirty(hdr) < 0)
-                        HGOTO_ERROR(H5E_HEAP, H5E_CANTDIRTY, FAIL, "can't mark heap header as dirty")
+            /* Check if we need to re-size the block on disk */
+            if(hdr->pline_root_direct_size != write_size || at_tmp_addr) {
+                /* Check if the direct block is NOT currently allocated 
+                 * in temp. file space 
+                 *
+                 * (temp. file space does not need to be freed) 
+                 */
+                if(!at_tmp_addr) {
+                    /* Release direct block's current disk space */
+                    if(H5MF_xfree(f, H5FD_MEM_FHEAP_DBLOCK, dxpl_id, addr, (hsize_t)hdr->pline_root_direct_size) < 0)
+                        HGOTO_ERROR(H5E_HEAP, H5E_CANTFREE, FAIL, "unable to free fractal heap direct block")
                 } /* end if */
-                else {
-                    H5HF_indirect_t *par_iblock;    /* Parent indirect block */
-                    unsigned par_entry;             /* Entry in parent indirect block */
 
-                    /* Get parent information */
-                    par_iblock = dblock->parent;
-                    par_entry = dblock->par_entry;
+                /* Allocate space for the compressed direct block */
+                if(HADDR_UNDEF == (dblock_addr = H5MF_alloc((H5F_t *)f, H5FD_MEM_FHEAP_DBLOCK, dxpl_id, (hsize_t)write_size)))
+                    HGOTO_ERROR(H5E_HEAP, H5E_NOSPACE, FAIL, "file allocation failed for fractal heap direct block")
 
-                    /* Sanity check */
-                    HDassert(H5F_addr_eq(par_iblock->ents[par_entry].addr, addr));
+                /* Let the metadata cache know, if the block moved */
+                if(!H5F_addr_eq(hdr->man_dtable.table_addr, dblock_addr))
+                    if(H5AC_move_entry((H5F_t *)f, H5AC_FHEAP_DBLOCK, hdr->man_dtable.table_addr, dblock_addr) < 0)
+                        HGOTO_ERROR(H5E_HEAP, H5E_CANTMOVE, FAIL, "unable to move direct block")
 
-                    /* Allocate 'normal' space for the direct block */
-                    if(HADDR_UNDEF == (addr = H5MF_alloc(f, H5FD_MEM_FHEAP_DBLOCK, dxpl_id, (hsize_t)write_size)))
-                        HGOTO_ERROR(H5E_HEAP, H5E_NOSPACE, FAIL, "file allocation failed for fractal heap direct block")
+                /* Update information about compressed direct block's 
+                 * location & size 
+                 */
+                HDassert(hdr->man_dtable.table_addr == addr);
+                HDassert(hdr->pline_root_direct_size == compressed_len);
+                hdr->man_dtable.table_addr = dblock_addr;
+                hdr->pline_root_direct_size = write_size;
 
-                    /* Sanity check */
-                    HDassert(!H5F_addr_eq(par_iblock->ents[par_entry].addr, addr));
+                /* Note that heap header was modified */
+                hdr_changed = TRUE;
+            } /* end if */
+
+            /* Check if heap header was modified */
+            if(hdr_changed)
+                if(H5HF_hdr_dirty(hdr) < 0)
+                    HGOTO_ERROR(H5E_HEAP, H5E_CANTDIRTY, FAIL, "can't mark heap header as dirty")
+        } /* end if */
+        else { /* the direct block's parent is an indirect block */
+            hbool_t par_changed = FALSE;  /* Whether the parent's infochanged */
 
-                    /* Let the metadata cache know the block moved */
-                    if(H5AC_move_entry(f, H5AC_FHEAP_DBLOCK, par_iblock->ents[par_entry].addr, addr) < 0)
+            /* Sanity check */
+            HDassert(par_iblock);
+            HDassert(par_iblock->filt_ents[par_entry].size > 0);
+
+            /* Check if the filter mask changed */
+            if(par_iblock->filt_ents[par_entry].filter_mask != filter_mask) {
+                par_iblock->filt_ents[par_entry].filter_mask = filter_mask;
+                par_changed = TRUE;
+            } /* end if */
+
+            /* verify that the cache's last record of the compressed 
+             * size matches the heap's last record.  This value will
+             * likely change shortly.
+             */
+            HDassert(compressed_len == par_iblock->filt_ents[par_entry].size);
+
+            /* Check if we need to re-size the block on disk */
+            if(par_iblock->filt_ents[par_entry].size != write_size || at_tmp_addr) {
+                /* Check if the direct block is NOT currently allocated 
+                 * in temp. file space 
+                 *
+                 * (temp. file space does not need to be freed) 
+                 */
+                if(!at_tmp_addr) {
+                    /* Release direct block's current disk space */
+                    if(H5MF_xfree(f, H5FD_MEM_FHEAP_DBLOCK, dxpl_id, addr, (hsize_t)par_iblock->filt_ents[par_entry].size) < 0)
+                        HGOTO_ERROR(H5E_HEAP, H5E_CANTFREE, FAIL, "unable to free fractal heap direct block")
+                } /* end if */
+
+                /* Allocate space for the compressed direct block */
+                if(HADDR_UNDEF == (dblock_addr = H5MF_alloc((H5F_t *)f, H5FD_MEM_FHEAP_DBLOCK, dxpl_id, (hsize_t)write_size)))
+                    HGOTO_ERROR(H5E_HEAP, H5E_NOSPACE, FAIL, "file allocation failed for fractal heap direct block")
+
+                /* Let the metadata cache know, if the block moved */
+                if(!H5F_addr_eq(par_iblock->ents[par_entry].addr, dblock_addr))
+                    if(H5AC_move_entry((H5F_t *)f, H5AC_FHEAP_DBLOCK, par_iblock->ents[par_entry].addr, dblock_addr) < 0)
                         HGOTO_ERROR(H5E_HEAP, H5E_CANTMOVE, FAIL, "unable to move direct block")
 
-                    /* Update information about direct block's location */
-                    par_iblock->ents[par_entry].addr = addr;
+                /* Update information about compressed direct block's 
+                 * location & size 
+                 */
+                HDassert(par_iblock->ents[par_entry].addr == addr);
+                HDassert(par_iblock->filt_ents[par_entry].size == compressed_len);
+                par_iblock->ents[par_entry].addr = dblock_addr;
+                par_iblock->filt_ents[par_entry].size = write_size;
 
-                    /* Mark that parent was modified */
-                    if(H5HF_iblock_dirty(par_iblock) < 0)
-                        HGOTO_ERROR(H5E_HEAP, H5E_CANTDIRTY, FAIL, "can't mark heap header as dirty")
-                } /* end else */
+                /* Note that parent was modified */
+                par_changed = TRUE;
             } /* end if */
+
+            /* Check if parent was modified */
+            if(par_changed)
+                if(H5HF_iblock_dirty(par_iblock) < 0)
+                    HGOTO_ERROR(H5E_HEAP, H5E_CANTDIRTY, FAIL, "can't mark heap header as dirty")
         } /* end else */
+    } /* end if */
+    else {
+        /* I/O filters are not enabled -- thus all we need to do is check to 
+         * see if the direct block is in temporary (AKA imaginary) file 
+         * space, and move it to real file space if it is.
+         *
+         * As in the I/O filters case above, we will have to touch up the 
+         * direct blocks parent if the direct block is relocated.
+         *
+         * Recall that temporary file space need not be freed, which 
+         * simplifies matters slightly.
+         */
+        write_buf = dblock->blk;
+        write_size = dblock->size;
 
-        /* Direct block must be in 'normal' file space now */
-        HDassert(!H5F_IS_TMP_ADDR(f, addr));
+        /* Check to see if we must re-allocate direct block from 'temp.' 
+         * to 'normal' file space 
+         */
+        if(at_tmp_addr) {
+            /* Check for root direct block */
+            if(NULL == dblock->parent) {
+                /* Sanity check */
+                HDassert(H5F_addr_eq(hdr->man_dtable.table_addr, addr));
 
-	/* Write the direct block */
-	if(H5F_block_write(f, H5FD_MEM_FHEAP_DBLOCK, addr, write_size, dxpl_id, write_buf) < 0)
-	    HGOTO_ERROR(H5E_HEAP, H5E_CANTFLUSH, FAIL, "unable to save fractal heap direct block to disk")
+                /* Allocate 'normal' space for the direct block */
+                if(HADDR_UNDEF == (dblock_addr = H5MF_alloc((H5F_t *)f, H5FD_MEM_FHEAP_DBLOCK, dxpl_id, (hsize_t)write_size)))
+                    HGOTO_ERROR(H5E_HEAP, H5E_NOSPACE, FAIL, "file allocation failed for fractal heap direct block")
 
-        /* Release the write buffer, if it was allocated */
-        if(write_buf != dblock->blk)
-            H5MM_xfree(write_buf);
+                /* Sanity check */
+                HDassert(!H5F_addr_eq(hdr->man_dtable.table_addr, dblock_addr));
 
-	dblock->cache_info.is_dirty = FALSE;
-    } /* end if */
+                /* Let the metadata cache know the block moved */
+                if(H5AC_move_entry((H5F_t *)f, H5AC_FHEAP_DBLOCK, hdr->man_dtable.table_addr, dblock_addr) < 0)
+                    HGOTO_ERROR(H5E_HEAP, H5E_CANTMOVE, FAIL, "unable to move direct block")
 
-    if(destroy)
-        if(H5HF_cache_dblock_dest(f, dblock) < 0)
-	    HGOTO_ERROR(H5E_HEAP, H5E_CANTFREE, FAIL, "unable to destroy fractal heap direct block")
+                /* Update information about direct block's location */
+                hdr->man_dtable.table_addr = dblock_addr;
 
-done:
-    FUNC_LEAVE_NOAPI(ret_value)
-} /* H5HF_cache_dblock_flush() */
+                /* Mark that heap header was modified */
+                if(H5HF_hdr_dirty(hdr) < 0)
+                    HGOTO_ERROR(H5E_HEAP, H5E_CANTDIRTY, FAIL, "can't mark heap header as dirty")
+            } /* end if */
+            else { /* the direct block's parent is an indirect block */
+                /* Sanity check */
+                HDassert(par_iblock);
+                HDassert(H5F_addr_eq(par_iblock->ents[par_entry].addr, addr));
 
-
-/*-------------------------------------------------------------------------
- * Function:	H5HF_cache_dblock_dest
- *
- * Purpose:	Destroys a fractal heap direct block in memory.
- *
- * Return:	Non-negative on success/Negative on failure
- *
- * Programmer:	Quincey Koziol
- *		koziol@ncsa.uiuc.edu
- *		Feb 27 2006
- *
- *-------------------------------------------------------------------------
- */
-static herr_t
-H5HF_cache_dblock_dest(H5F_t *f, H5HF_direct_t *dblock)
-{
-    herr_t      ret_value = SUCCEED;    /* Return value */
+                /* Allocate 'normal' space for the direct block */
+                if(HADDR_UNDEF == (dblock_addr = H5MF_alloc((H5F_t *)f, H5FD_MEM_FHEAP_DBLOCK, dxpl_id, (hsize_t)write_size)))
+                    HGOTO_ERROR(H5E_HEAP, H5E_NOSPACE, FAIL, "file allocation failed for fractal heap direct block")
 
-    FUNC_ENTER_NOAPI_NOINIT
+                /* Sanity check */
+                HDassert(!H5F_addr_eq(par_iblock->ents[par_entry].addr, dblock_addr));
 
-    /*
-     * Check arguments.
-     */
-    HDassert(dblock);
+                /* Let the metadata cache know the block moved */
+                if(H5AC_move_entry((H5F_t *)f, H5AC_FHEAP_DBLOCK, par_iblock->ents[par_entry].addr, dblock_addr) < 0)
+                    HGOTO_ERROR(H5E_HEAP, H5E_CANTMOVE, FAIL, "unable to move direct block")
 
-    /* If we're going to free the space on disk, the address must be valid */
-    HDassert(!dblock->cache_info.free_file_space_on_destroy || H5F_addr_defined(dblock->cache_info.addr));
+                /* Update information about direct block's location */
+                par_iblock->ents[par_entry].addr = dblock_addr;
 
-    /* Check for freeing file space for direct block */
-    if(dblock->cache_info.free_file_space_on_destroy) {
-        /* Sanity check */
-        HDassert(dblock->file_size > 0);
-
-        /* Check if the direct block is NOT currently allocated in temp. file space */
-        /* (temp. file space does not need to be freed) */
-        if(!H5F_IS_TMP_ADDR(f, dblock->cache_info.addr)) {
-            /* Release the space on disk */
-            /* (XXX: Nasty usage of internal DXPL value! -QAK) */
-            if(H5MF_xfree(f, H5FD_MEM_FHEAP_DBLOCK, H5AC_dxpl_id, dblock->cache_info.addr, dblock->file_size) < 0)
-                HGOTO_ERROR(H5E_HEAP, H5E_CANTFREE, FAIL, "unable to free fractal heap direct block")
+                /* Mark that parent was modified */
+                if(H5HF_iblock_dirty(par_iblock) < 0)
+                    HGOTO_ERROR(H5E_HEAP, H5E_CANTDIRTY, FAIL, "can't mark heap header as dirty")
+            } /* end else */
         } /* end if */
+    } /* end else */
+
+    /* At this point, write_buf points to a buffer containing the image 
+     * of the direct block that is ready to copy into the image buffer,
+     * and write_size contains the length of this buffer. 
+     *
+     * Also, if image size or address has changed, the direct block's
+     * parent has been modified to reflect the change.
+     *
+     * Now, make note of the pointer and length of the above buffer for
+     * use by the serialize function.
+     */
+    dblock->write_buf = (uint8_t *)write_buf;
+    dblock->write_size = write_size;
+
+    /* finally, pass data back to the metadata cache as appropriate */
+    if(!H5F_addr_eq(addr, dblock_addr)) {
+        dblock_flags |= H5C__SERIALIZE_MOVED_FLAG;
+        *new_addr = dblock_addr;
     } /* end if */
 
-    /* Destroy fractal heap direct block */
-    if(H5HF_man_dblock_dest(dblock) < 0)
-        HGOTO_ERROR(H5E_HEAP, H5E_CANTFREE, FAIL, "unable to destroy fractal heap direct block")
+    if((hdr->filter_len > 0) && (compressed_len != write_size)) {
+        dblock_flags |= H5C__SERIALIZE_COMPRESSED_FLAG;
+        *new_compressed_len = write_size;
+    } /* end if */
+
+    *flags = dblock_flags;
+
+    /* final sanity check */
+    HDassert(dblock->write_buf);
+    HDassert(dblock->write_size > 0);
 
 done:
+    /* discard the write buf if we have an error */
+    if(write_buf && (write_buf != dblock->blk) && (dblock->write_buf == NULL))
+	H5MM_xfree(write_buf);
+
     FUNC_LEAVE_NOAPI(ret_value)
-} /* end H5HF_cache_dblock_dest() */
+} /* end H5HF__cache_dblock_pre_serialize() */
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5HF_cache_dblock_clear
+ * Function:	H5HF__cache_dblock_serialize
  *
- * Purpose:	Mark a fractal heap direct block in memory as non-dirty.
+ * Purpose:	In principle, this function is supposed to construct the on 
+ *		disk image of the direct block, and place that image in the 
+ *		image buffer provided by the metadata cache.
  *
- * Return:	Non-negative on success/Negative on failure
+ *		However, since there are cases in which the pre_serialize 
+ *		function has to construct the on disk image to determine its size 
+ *		and address, this function simply copies the image prepared by
+ *		the pre-serialize function into the supplied image buffer, and 
+ *		discards a buffer if necessary.
  *
- * Programmer:	Quincey Koziol
- *		koziol@ncsa.uiuc.edu
- *		Feb 27 2006
+ * Return:	Success:	SUCCEED
+ *		Failure:	FAIL
+ *
+ * Programmer:	John Mainzer
+ *		6/21/14
  *
  *-------------------------------------------------------------------------
  */
-static herr_t
-H5HF_cache_dblock_clear(H5F_t *f, H5HF_direct_t *dblock, hbool_t destroy)
+static herr_t 
+H5HF__cache_dblock_serialize(const H5F_t *f, void *image, size_t len,
+    void *_thing)
 {
-    herr_t ret_value = SUCCEED;         /* Return value */
+    H5HF_direct_t       *dblock = (H5HF_direct_t *)_thing;      /* Direct block info */
+    herr_t               ret_value = SUCCEED;    /* Return value */
 
-    FUNC_ENTER_NOAPI_NOINIT
+    FUNC_ENTER_STATIC_NOERR
 
-    /*
-     * Check arguments.
-     */
+    /* Sanity checks */
+    HDassert(f);
+    HDassert(image);
+    HDassert(len > 0);
     HDassert(dblock);
+    HDassert(dblock->cache_info.magic == H5C__H5C_CACHE_ENTRY_T_MAGIC);
+    HDassert(dblock->cache_info.type == H5AC_FHEAP_DBLOCK);
+    HDassert((dblock->blk != dblock->write_buf) || (dblock->cache_info.size == dblock->size));
+    HDassert(dblock->write_buf);
+    HDassert(dblock->write_size > 0);
+    HDassert((dblock->blk != dblock->write_buf) || (dblock->write_size == dblock->size));
+    HDassert(dblock->write_size == len);
+
+    /* Copy the image from *(dblock->write_buf) to *image */
+    HDmemcpy(image, dblock->write_buf, dblock->write_size);
+
+    /* Free *(dblock->write_buf) if it was allocated by the 
+     * pre-serialize function 
+     */
+    if(dblock->write_buf != dblock->blk)
+        H5MM_xfree(dblock->write_buf);
 
-    /* Reset the dirty flag.  */
-    dblock->cache_info.is_dirty = FALSE;
-
-    if(destroy)
-        if(H5HF_cache_dblock_dest(f, dblock) < 0)
-	    HGOTO_ERROR(H5E_HEAP, H5E_CANTFREE, FAIL, "unable to destroy fractal heap direct block")
+    /* Reset the write_buf and write_size fields */
+    dblock->write_buf = NULL;
+    dblock->write_size = 0;
 
-done:
     FUNC_LEAVE_NOAPI(ret_value)
-} /* end H5HF_cache_dblock_clear() */
+} /* end H5HF__cache_dblock_serialize() */
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5HF_cache_dblock_notify
+ * Function:	H5HF__cache_dblock_notify
  *
  * Purpose:	Setup / takedown flush dependencies as direct blocks
  *		are loaded / inserted and evicted from the metadata cache.
  *
- * Return:	Non-negative on success/Negative on failure
+ * Return:	Success:	SUCCEED
+ *		Failure:	FAIL
  *
  * Programmer:	John Mainzer
- *		5/17/14
+ *		6/21/14
  *
  *-------------------------------------------------------------------------
  */
-static herr_t
-H5HF_cache_dblock_notify(H5C_notify_action_t action, H5HF_direct_t *dblock)
+static herr_t 
+H5HF__cache_dblock_notify(H5C_notify_action_t action, void *_thing)
 {
-    herr_t ret_value = SUCCEED;         /* Return value */
+    H5HF_direct_t 	*dblock = (H5HF_direct_t *)_thing;      /* Fractal heap direct block */
+    herr_t 		 ret_value = SUCCEED;         /* Return value */
 
-    FUNC_ENTER_NOAPI_NOINIT
+    FUNC_ENTER_STATIC
 
-    /*
-     * Check arguments.
-     */
+    /* Sanity checks */
     HDassert(dblock);
     HDassert(dblock->cache_info.magic == H5C__H5C_CACHE_ENTRY_T_MAGIC);
+    HDassert(dblock->cache_info.type == H5AC_FHEAP_DBLOCK);
     HDassert(dblock->hdr);
     HDassert((dblock->fd_parent) ||
              ((dblock->hdr->man_dtable.curr_root_rows == 0) && (dblock->block_off == (hsize_t)0)));
 
     switch(action) {
         case H5AC_NOTIFY_ACTION_AFTER_INSERT:
+        case H5AC_NOTIFY_ACTION_AFTER_LOAD:
             HDassert(dblock->parent == dblock->fd_parent);
             if(dblock->parent) {        /* this is a leaf dblock */
                 /* create flush dependency with parent iblock */
@@ -1964,6 +2392,10 @@ H5HF_cache_dblock_notify(H5C_notify_action_t action, H5HF_direct_t *dblock)
             } /* end else */
             break;
 
+	case H5AC_NOTIFY_ACTION_AFTER_FLUSH:
+	    /* do nothing */
+	    break;
+
         case H5AC_NOTIFY_ACTION_BEFORE_EVICT:
             HDassert((dblock->parent == dblock->fd_parent) ||
                      ((NULL == dblock->parent) && (dblock->fd_parent)));
@@ -1986,39 +2418,47 @@ H5HF_cache_dblock_notify(H5C_notify_action_t action, H5HF_direct_t *dblock)
 
 done:
     FUNC_LEAVE_NOAPI(ret_value)
-} /* end H5HF_cache_dblock_notify() */
+} /* end H5HF__cache_dblock_notify() */
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5HF_cache_dblock_size
+ * Function:	H5HF__cache_dblock_free_icr
  *
- * Purpose:	Compute the size in bytes of a fractal heap direct block
- *		on disk, and return it in *size_ptr.  On failure,
- *		the value of *size_ptr is undefined.
+ * Purpose:	Free the in core memory allocated to the supplied direct
+ *		block.
  *
- * Return:	Non-negative on success/Negative on failure
+ * Note:	The metadata cache sets the object's cache_info.magic to
+ *		H5C__H5C_CACHE_ENTRY_T_BAD_MAGIC before calling a free_icr
+ *		callback (checked in assert).
  *
- * Programmer:	Quincey Koziol
- *		koziol@ncsa.uiuc.edu
- *		Feb 24 2006
+ * Return:	Success:	SUCCEED
+ *		Failure:	FAIL
+ *
+ * Programmer:	John Mainzer
+ *		6/21/14
  *
  *-------------------------------------------------------------------------
  */
-static herr_t
-H5HF_cache_dblock_size(const H5F_t H5_ATTR_UNUSED *f, const H5HF_direct_t *dblock, size_t *size_ptr)
+static herr_t 
+H5HF__cache_dblock_free_icr(void *_thing)
 {
-    FUNC_ENTER_NOAPI_NOINIT_NOERR
+    H5HF_direct_t       *dblock = (H5HF_direct_t *)_thing;      /* Fractal heap direct block */
+    herr_t      	 ret_value = SUCCEED;    /* Return value */
 
-    /* check arguments */
-    HDassert(dblock);
-    HDassert(size_ptr);
+    FUNC_ENTER_STATIC
 
-    /* Set size value */
-    *size_ptr = dblock->size;
+    /* Sanity checks */
+    HDassert(dblock);
+    HDassert(dblock->cache_info.magic == H5C__H5C_CACHE_ENTRY_T_BAD_MAGIC);
+    HDassert(dblock->cache_info.type == H5AC_FHEAP_DBLOCK);
 
-    FUNC_LEAVE_NOAPI(SUCCEED)
-} /* H5HF_cache_dblock_size() */
+    /* Destroy fractal heap direct block */
+    if(H5HF_man_dblock_dest(dblock) < 0)
+        HGOTO_ERROR(H5E_HEAP, H5E_CANTFREE, FAIL, "unable to destroy fractal heap direct block")
 
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5HF__cache_dblock_free_icr() */
 
 
 /*------------------------------------------------------------------------
@@ -2144,7 +2584,7 @@ H5HF__cache_verify_hdr_descendants_clean(H5F_t *f, hid_t dxpl_id,
                      * in this case, since we know that the entry is in cache,
                      * we can pass NULL udata.
 		     */
-                    if(NULL == (root_iblock = (H5HF_indirect_t *)H5AC_protect(f, dxpl_id, H5AC_FHEAP_IBLOCK, root_iblock_addr, NULL, H5AC_READ)))
+                    if(NULL == (root_iblock = (H5HF_indirect_t *)H5AC_protect(f, dxpl_id, H5AC_FHEAP_IBLOCK, root_iblock_addr, NULL, H5C__READ_ONLY_FLAG)))
                         HGOTO_ERROR(H5E_HEAP, H5E_CANTPROTECT, FAIL, "H5AC_protect() faild.")
                     unprotect_root_iblock = TRUE;
 		} /* end if */
@@ -2205,7 +2645,7 @@ H5HF__cache_verify_hdr_descendants_clean(H5F_t *f, hid_t dxpl_id,
                      * in this case, since we know that the entry is in cache,
                      * we can pass NULL udata.
                      */
-                    if(NULL == (iblock = (H5HF_indirect_t *)H5AC_protect(f, dxpl_id, H5AC_FHEAP_IBLOCK, root_iblock_addr, NULL, H5AC_READ)))
+                    if(NULL == (iblock = (H5HF_indirect_t *)H5AC_protect(f, dxpl_id, H5AC_FHEAP_IBLOCK, root_iblock_addr, NULL, H5C__READ_ONLY_FLAG)))
                         HGOTO_ERROR(H5E_HEAP, H5E_CANTPROTECT, FAIL, "H5AC_protect() faild.")
                     unprotect_root_iblock = TRUE;
                     HDassert(iblock == root_iblock);
@@ -2595,7 +3035,7 @@ H5HF__cache_verify_descendant_iblocks_clean(H5F_t *f, hid_t dxpl_id,
 			    /* in this case, since we know that the      */
 			    /* entry is in cache, we can pass NULL udata */
 
-			    if(NULL == (child_iblock = (H5HF_indirect_t *) H5AC_protect(f, dxpl_id, H5AC_FHEAP_IBLOCK, child_iblock_addr, NULL, H5AC_READ)))
+			    if(NULL == (child_iblock = (H5HF_indirect_t *) H5AC_protect(f, dxpl_id, H5AC_FHEAP_IBLOCK, child_iblock_addr, NULL, H5C__READ_ONLY_FLAG)))
                                 HGOTO_ERROR(H5E_HEAP, H5E_CANTPROTECT, FAIL, "H5AC_protect() faild.")
 			    unprotect_child_iblock = TRUE;
 			} /* end if */
diff --git a/src/H5HFdbg.c b/src/H5HFdbg.c
index 8620f6f..5183b67 100644
--- a/src/H5HFdbg.c
+++ b/src/H5HFdbg.c
@@ -323,7 +323,7 @@ H5HF_hdr_debug(H5F_t *f, hid_t dxpl_id, haddr_t addr, FILE *stream, int indent,
     HDassert(fwidth >= 0);
 
     /* Load the fractal heap header */
-    if(NULL == (hdr = H5HF_hdr_protect(f, dxpl_id, addr, H5AC_READ)))
+    if(NULL == (hdr = H5HF_hdr_protect(f, dxpl_id, addr, H5AC__READ_ONLY_FLAG)))
 	HGOTO_ERROR(H5E_HEAP, H5E_CANTPROTECT, FAIL, "unable to protect fractal heap header")
 
     /* Print the information about the heap's header */
@@ -459,13 +459,13 @@ H5HF_dblock_debug(H5F_t *f, hid_t dxpl_id, haddr_t addr, FILE *stream,
     HDassert(block_size > 0);
 
     /* Load the fractal heap header */
-    if(NULL == (hdr = H5HF_hdr_protect(f, dxpl_id, hdr_addr, H5AC_READ)))
+    if(NULL == (hdr = H5HF_hdr_protect(f, dxpl_id, hdr_addr, H5AC__READ_ONLY_FLAG)))
 	HGOTO_ERROR(H5E_HEAP, H5E_CANTPROTECT, FAIL, "unable to protect fractal heap header")
 
     /*
      * Load the heap direct block
      */
-    if(NULL == (dblock = H5HF_man_dblock_protect(hdr, dxpl_id, addr, block_size, NULL, 0, H5AC_READ)))
+    if(NULL == (dblock = H5HF_man_dblock_protect(hdr, dxpl_id, addr, block_size, NULL, 0, H5AC__READ_ONLY_FLAG)))
 	HGOTO_ERROR(H5E_HEAP, H5E_CANTLOAD, FAIL, "unable to load fractal heap direct block")
 
     /* Print opening message */
@@ -716,13 +716,13 @@ H5HF_iblock_debug(H5F_t *f, hid_t dxpl_id, haddr_t addr, FILE *stream,
     HDassert(nrows > 0);
 
     /* Load the fractal heap header */
-    if(NULL == (hdr = H5HF_hdr_protect(f, dxpl_id, hdr_addr, H5AC_READ)))
+    if(NULL == (hdr = H5HF_hdr_protect(f, dxpl_id, hdr_addr, H5AC__READ_ONLY_FLAG)))
 	HGOTO_ERROR(H5E_HEAP, H5E_CANTPROTECT, FAIL, "unable to protect fractal heap header")
 
     /*
      * Load the heap indirect block
      */
-    if(NULL == (iblock = H5HF_man_iblock_protect(hdr, dxpl_id, addr, nrows, NULL, 0, FALSE, H5AC_READ, &did_protect)))
+    if(NULL == (iblock = H5HF_man_iblock_protect(hdr, dxpl_id, addr, nrows, NULL, 0, FALSE, H5AC__READ_ONLY_FLAG, &did_protect)))
 	HGOTO_ERROR(H5E_HEAP, H5E_CANTLOAD, FAIL, "unable to load fractal heap indirect block")
 
     /* Print the information about the heap's indirect block */
@@ -825,7 +825,7 @@ H5HF_sects_debug(H5F_t *f, hid_t dxpl_id, haddr_t fh_addr,
     HDassert(fwidth >= 0);
 
     /* Load the fractal heap header */
-    if(NULL == (hdr = H5HF_hdr_protect(f, dxpl_id, fh_addr, H5AC_READ)))
+    if(NULL == (hdr = H5HF_hdr_protect(f, dxpl_id, fh_addr, H5AC__READ_ONLY_FLAG)))
 	HGOTO_ERROR(H5E_HEAP, H5E_CANTPROTECT, FAIL, "unable to protect fractal heap header")
 
     /* Initialize the free space information for the heap */
diff --git a/src/H5HFdblock.c b/src/H5HFdblock.c
index 9a8da4a..5dd5b0c 100644
--- a/src/H5HFdblock.c
+++ b/src/H5HFdblock.c
@@ -149,6 +149,9 @@ H5HF_man_dblock_create(hid_t dxpl_id, H5HF_hdr_t *hdr, H5HF_indirect_t *par_iblo
 HDmemset(dblock->blk, 0, dblock->size);
 #endif /* H5_CLEAR_MEMORY */
 
+    dblock->write_buf = NULL;
+    dblock->write_size = 0;
+
     /* Allocate [temporary] space for the direct block on disk */
     if(H5F_USE_TMP_SPACE(hdr->f)) {
         if(HADDR_UNDEF == (dblock_addr = H5MF_alloc_tmp(hdr->f, (hsize_t)dblock->size)))
@@ -308,9 +311,13 @@ H5HF_man_dblock_destroy(H5HF_hdr_t *hdr, hid_t dxpl_id, H5HF_direct_t *dblock,
         } /* end if */
     } /* end else */
 
-    /* Indicate that the indirect block should be deleted & file space freed */
+    /* Indicate that the indirect block should be deleted */
     dblock->file_size = dblock_size;
-    cache_flags |= H5AC__DIRTIED_FLAG | H5AC__DELETED_FLAG | H5AC__FREE_FILE_SPACE_FLAG;
+    cache_flags |= H5AC__DIRTIED_FLAG | H5AC__DELETED_FLAG;
+
+    /* If the dblock is in real file space, also tell the cache to free its file space */
+    if (!H5F_IS_TMP_ADDR(hdr->f, dblock_addr))
+        cache_flags |= H5AC__FREE_FILE_SPACE_FLAG;
 
 done:
     /* Unprotect the indirect block, with appropriate flags */
@@ -436,7 +443,7 @@ done:
 H5HF_direct_t *
 H5HF_man_dblock_protect(H5HF_hdr_t *hdr, hid_t dxpl_id, haddr_t dblock_addr,
     size_t dblock_size, H5HF_indirect_t *par_iblock, unsigned par_entry,
-    H5AC_protect_t rw)
+    unsigned flags)
 {
     H5HF_direct_t *dblock;      /* Direct block from cache */
     H5HF_dblock_cache_ud_t udata;	/* parent and other infor for deserializing direct block */
@@ -451,6 +458,9 @@ H5HF_man_dblock_protect(H5HF_hdr_t *hdr, hid_t dxpl_id, haddr_t dblock_addr,
     HDassert(H5F_addr_defined(dblock_addr));
     HDassert(dblock_size > 0);
 
+    /* only H5AC__READ_ONLY_FLAG may appear in flags */
+    HDassert((flags & (~H5AC__READ_ONLY_FLAG)) == 0);
+
     /* Set up parent info */
     udata.par_info.hdr = hdr;
     udata.par_info.iblock = par_iblock;
@@ -485,7 +495,7 @@ H5HF_man_dblock_protect(H5HF_hdr_t *hdr, hid_t dxpl_id, haddr_t dblock_addr,
     } /* end else */
 
     /* Protect the direct block */
-    if(NULL == (dblock = (H5HF_direct_t *)H5AC_protect(hdr->f, dxpl_id, H5AC_FHEAP_DBLOCK, dblock_addr, &udata, rw)))
+    if(NULL == (dblock = (H5HF_direct_t *)H5AC_protect(hdr->f, dxpl_id, H5AC_FHEAP_DBLOCK, dblock_addr, &udata, flags)))
         HGOTO_ERROR(H5E_HEAP, H5E_CANTPROTECT, NULL, "unable to protect fractal heap direct block")
 
     /* Set the return value */
@@ -512,7 +522,7 @@ done:
 herr_t
 H5HF_man_dblock_locate(H5HF_hdr_t *hdr, hid_t dxpl_id, hsize_t obj_off,
     H5HF_indirect_t **ret_iblock, unsigned *ret_entry, hbool_t *ret_did_protect,
-    H5AC_protect_t rw)
+    unsigned flags)
 {
     haddr_t iblock_addr;            /* Indirect block's address */
     H5HF_indirect_t *iblock;        /* Pointer to indirect block */
@@ -531,6 +541,9 @@ H5HF_man_dblock_locate(H5HF_hdr_t *hdr, hid_t dxpl_id, hsize_t obj_off,
     HDassert(ret_iblock);
     HDassert(ret_did_protect);
 
+    /* only H5AC__READ_ONLY_FLAG may appear in flags */
+    HDassert((flags & (~H5AC__READ_ONLY_FLAG)) == 0);
+
     /* Look up row & column for object */
     if(H5HF_dtable_lookup(&hdr->man_dtable, obj_off, &row, &col) < 0)
         HGOTO_ERROR(H5E_HEAP, H5E_CANTCOMPUTE, FAIL, "can't compute row & column of object")
@@ -539,7 +552,7 @@ H5HF_man_dblock_locate(H5HF_hdr_t *hdr, hid_t dxpl_id, hsize_t obj_off,
     iblock_addr = hdr->man_dtable.table_addr;
 
     /* Lock root indirect block */
-    if(NULL == (iblock = H5HF_man_iblock_protect(hdr, dxpl_id, iblock_addr, hdr->man_dtable.curr_root_rows, NULL, 0, FALSE, rw, &did_protect)))
+    if(NULL == (iblock = H5HF_man_iblock_protect(hdr, dxpl_id, iblock_addr, hdr->man_dtable.curr_root_rows, NULL, 0, FALSE, flags, &did_protect)))
         HGOTO_ERROR(H5E_HEAP, H5E_CANTPROTECT, FAIL, "unable to protect fractal heap indirect block")
 
     /* Check for indirect block row */
@@ -569,7 +582,7 @@ H5HF_man_dblock_locate(H5HF_hdr_t *hdr, hid_t dxpl_id, hsize_t obj_off,
         } /* end if */
 
         /* Lock child indirect block */
-        if(NULL == (new_iblock = H5HF_man_iblock_protect(hdr, dxpl_id, iblock_addr, nrows, iblock, entry, FALSE, rw, &new_did_protect)))
+        if(NULL == (new_iblock = H5HF_man_iblock_protect(hdr, dxpl_id, iblock_addr, nrows, iblock, entry, FALSE, flags, &new_did_protect)))
             HGOTO_ERROR(H5E_HEAP, H5E_CANTPROTECT, FAIL, "unable to protect fractal heap indirect block")
 
         /* Release the current indirect block */
diff --git a/src/H5HFhdr.c b/src/H5HFhdr.c
index cf8da23..340940f 100644
--- a/src/H5HFhdr.c
+++ b/src/H5HFhdr.c
@@ -529,7 +529,7 @@ done:
  *-------------------------------------------------------------------------
  */
 H5HF_hdr_t *
-H5HF_hdr_protect(H5F_t *f, hid_t dxpl_id, haddr_t addr, H5AC_protect_t rw)
+H5HF_hdr_protect(H5F_t *f, hid_t dxpl_id, haddr_t addr, unsigned flags)
 {
     H5HF_hdr_cache_ud_t cache_udata;    /* User-data for callback */
     H5HF_hdr_t *hdr;                    /* Fractal heap header */
@@ -541,12 +541,15 @@ H5HF_hdr_protect(H5F_t *f, hid_t dxpl_id, haddr_t addr, H5AC_protect_t rw)
     HDassert(f);
     HDassert(H5F_addr_defined(addr));
 
+    /* only H5AC__READ_ONLY_FLAG may appear in flags */
+    HDassert((flags & (unsigned)(~H5AC__READ_ONLY_FLAG)) == 0);
+
     /* Set up userdata for protect call */
     cache_udata.f = f;
     cache_udata.dxpl_id = dxpl_id;
 
     /* Lock the heap header into memory */
-    if(NULL == (hdr = (H5HF_hdr_t *)H5AC_protect(f, dxpl_id, H5AC_FHEAP_HDR, addr, &cache_udata, rw)))
+    if(NULL == (hdr = (H5HF_hdr_t *)H5AC_protect(f, dxpl_id, H5AC_FHEAP_HDR, addr, &cache_udata, flags)))
         HGOTO_ERROR(H5E_HEAP, H5E_CANTPROTECT, NULL, "unable to protect fractal heap header")
 
     /* Set the header's address */
@@ -1109,7 +1112,7 @@ H5HF_hdr_update_iter(H5HF_hdr_t *hdr, hid_t dxpl_id, size_t min_dblock_size)
                         HGOTO_ERROR(H5E_HEAP, H5E_CANTALLOC, FAIL, "can't allocate fractal heap indirect block")
 
                     /* Lock new indirect block */
-                    if(NULL == (new_iblock = H5HF_man_iblock_protect(hdr, dxpl_id, new_iblock_addr, child_nrows, iblock, next_entry, FALSE, H5AC_WRITE, &did_protect)))
+                    if(NULL == (new_iblock = H5HF_man_iblock_protect(hdr, dxpl_id, new_iblock_addr, child_nrows, iblock, next_entry, FALSE, H5AC__NO_FLAGS_SET, &did_protect)))
                         HGOTO_ERROR(H5E_HEAP, H5E_CANTPROTECT, FAIL, "unable to protect fractal heap indirect block")
 
                     /* Move iterator down one level (pins indirect block) */
@@ -1303,7 +1306,7 @@ H5HF_hdr_reverse_iter(H5HF_hdr_t *hdr, hid_t dxpl_id, haddr_t dblock_addr)
                 child_nrows = H5HF_dtable_size_to_rows(&hdr->man_dtable, hdr->man_dtable.row_block_size[row]);
 
                 /* Lock child indirect block */
-                if(NULL == (child_iblock = H5HF_man_iblock_protect(hdr, dxpl_id, iblock->ents[curr_entry].addr, child_nrows, iblock, curr_entry, FALSE, H5AC_WRITE, &did_protect)))
+                if(NULL == (child_iblock = H5HF_man_iblock_protect(hdr, dxpl_id, iblock->ents[curr_entry].addr, child_nrows, iblock, curr_entry, FALSE, H5AC__NO_FLAGS_SET, &did_protect)))
                     HGOTO_ERROR(H5E_HEAP, H5E_CANTPROTECT, FAIL, "unable to protect fractal heap indirect block")
 
                 /* Set the current location of the iterator */
diff --git a/src/H5HFiblock.c b/src/H5HFiblock.c
index 4473803..547aaf0 100644
--- a/src/H5HFiblock.c
+++ b/src/H5HFiblock.c
@@ -330,8 +330,15 @@ H5HF_iblock_decr(H5HF_indirect_t *iblock)
 
 	/* Check for expunging the indirect block from the metadata cache */
 	if(expunge_iblock) {
-            /* Evict the indirect block from the metadata cache */
-            if(H5AC_expunge_entry(hdr->f, H5AC_dxpl_id, H5AC_FHEAP_IBLOCK, iblock_addr, H5AC__FREE_FILE_SPACE_FLAG) < 0)
+            unsigned cache_flags = H5AC__NO_FLAGS_SET;
+
+            /* if the indirect block is in real file space, tell 
+             * the cache to free its file space.
+             */
+            if (!H5F_IS_TMP_ADDR(hdr->f, iblock_addr))
+                cache_flags |= H5AC__FREE_FILE_SPACE_FLAG;
+
+            if(H5AC_expunge_entry(hdr->f, H5AC_dxpl_id, H5AC_FHEAP_IBLOCK, iblock_addr, cache_flags) < 0)
                 HGOTO_ERROR(H5E_HEAP, H5E_CANTREMOVE, FAIL, "unable to remove indirect block from cache")
         } /* end if */
     } /* end if */
@@ -424,7 +431,7 @@ H5HF_man_iblock_root_create(H5HF_hdr_t *hdr, hid_t dxpl_id, size_t min_dblock_si
     /* Move current direct block (used as root) into new indirect block */
 
     /* Lock new indirect block */
-    if(NULL == (iblock = H5HF_man_iblock_protect(hdr, dxpl_id, iblock_addr, nrows, NULL, 0, FALSE, H5AC_WRITE, &did_protect)))
+    if(NULL == (iblock = H5HF_man_iblock_protect(hdr, dxpl_id, iblock_addr, nrows, NULL, 0, FALSE, H5AC__NO_FLAGS_SET, &did_protect)))
         HGOTO_ERROR(H5E_HEAP, H5E_CANTPROTECT, FAIL, "unable to protect fractal heap indirect block")
 
     /* Check if there's already a direct block as root) */
@@ -433,7 +440,7 @@ H5HF_man_iblock_root_create(H5HF_hdr_t *hdr, hid_t dxpl_id, size_t min_dblock_si
         H5HF_direct_t *dblock;          /* Pointer to direct block to query */
 
         /* Lock first (root) direct block */
-        if(NULL == (dblock = H5HF_man_dblock_protect(hdr, dxpl_id, hdr->man_dtable.table_addr, hdr->man_dtable.cparam.start_block_size, NULL, 0, H5AC_WRITE)))
+        if(NULL == (dblock = H5HF_man_dblock_protect(hdr, dxpl_id, hdr->man_dtable.table_addr, hdr->man_dtable.cparam.start_block_size, NULL, 0, H5AC__NO_FLAGS_SET)))
             HGOTO_ERROR(H5E_HEAP, H5E_CANTPROTECT, FAIL, "unable to protect fractal heap direct block")
 
         /* Attach direct block to new root indirect block */
@@ -879,7 +886,7 @@ H5HF_man_iblock_root_revert(H5HF_indirect_t *root_iblock, hid_t dxpl_id)
     dblock_size = hdr->man_dtable.cparam.start_block_size;
 
     /* Get pointer to last direct block */
-    if(NULL == (dblock = H5HF_man_dblock_protect(hdr, dxpl_id, dblock_addr, dblock_size, root_iblock, 0, H5AC_WRITE)))
+    if(NULL == (dblock = H5HF_man_dblock_protect(hdr, dxpl_id, dblock_addr, dblock_size, root_iblock, 0, H5AC__NO_FLAGS_SET)))
         HGOTO_ERROR(H5E_HEAP, H5E_CANTPROTECT, FAIL, "unable to protect fractal heap direct block")
     HDassert(dblock->parent == root_iblock);
     HDassert(dblock->par_entry == 0);
@@ -1159,7 +1166,7 @@ done:
 H5HF_indirect_t *
 H5HF_man_iblock_protect(H5HF_hdr_t *hdr, hid_t dxpl_id, haddr_t iblock_addr,
     unsigned iblock_nrows, H5HF_indirect_t *par_iblock, unsigned par_entry,
-    hbool_t must_protect, H5AC_protect_t rw, hbool_t *did_protect)
+    hbool_t must_protect, unsigned flags, hbool_t *did_protect)
 {
     H5HF_parent_t par_info;             /* Parent info for loading block */
     H5HF_indirect_t *iblock = NULL;     /* Indirect block from cache */
@@ -1176,6 +1183,9 @@ H5HF_man_iblock_protect(H5HF_hdr_t *hdr, hid_t dxpl_id, haddr_t iblock_addr,
     HDassert(iblock_nrows > 0);
     HDassert(did_protect);
 
+    /* only H5AC__READ_ONLY_FLAG may appear in flags */
+    HDassert((flags & (unsigned)(~H5AC__READ_ONLY_FLAG)) == 0);
+
     /* Check if we are allowed to use existing pinned iblock pointer */
     if(!must_protect) {
         /* Check for this block already being pinned */
@@ -1235,7 +1245,7 @@ H5HF_man_iblock_protect(H5HF_hdr_t *hdr, hid_t dxpl_id, haddr_t iblock_addr,
         cache_udata.nrows = &iblock_nrows;
 
         /* Protect the indirect block */
-        if(NULL == (iblock = (H5HF_indirect_t *)H5AC_protect(hdr->f, dxpl_id, H5AC_FHEAP_IBLOCK, iblock_addr, &cache_udata, rw)))
+        if(NULL == (iblock = (H5HF_indirect_t *)H5AC_protect(hdr->f, dxpl_id, H5AC_FHEAP_IBLOCK, iblock_addr, &cache_udata, flags)))
             HGOTO_ERROR(H5E_HEAP, H5E_CANTPROTECT, NULL, "unable to protect fractal heap indirect block")
 
         /* Set the indirect block's address */
@@ -1579,7 +1589,7 @@ H5HF_man_iblock_delete(H5HF_hdr_t *hdr, hid_t dxpl_id, haddr_t iblock_addr,
     HDassert(iblock_nrows > 0);
 
     /* Lock indirect block */
-    if(NULL == (iblock = H5HF_man_iblock_protect(hdr, dxpl_id, iblock_addr, iblock_nrows, par_iblock, par_entry, TRUE, H5AC_WRITE, &did_protect)))
+    if(NULL == (iblock = H5HF_man_iblock_protect(hdr, dxpl_id, iblock_addr, iblock_nrows, par_iblock, par_entry, TRUE, H5AC__NO_FLAGS_SET, &did_protect)))
         HGOTO_ERROR(H5E_HEAP, H5E_CANTPROTECT, FAIL, "unable to protect fractal heap indirect block")
     HDassert(iblock->nchildren > 0);
     HDassert(did_protect == TRUE);
@@ -1637,8 +1647,14 @@ H5HF_man_iblock_delete(H5HF_hdr_t *hdr, hid_t dxpl_id, haddr_t iblock_addr,
 }
 #endif /* NDEBUG */
 
-    /* Indicate that the indirect block should be deleted & file space freed */
-    cache_flags |= H5AC__DIRTIED_FLAG | H5AC__DELETED_FLAG | H5AC__FREE_FILE_SPACE_FLAG;
+    /* Indicate that the indirect block should be deleted  */
+    cache_flags |= H5AC__DIRTIED_FLAG | H5AC__DELETED_FLAG;
+
+    /* If the indirect block is in real file space, tell
+     * the cache to free its file space as well.
+     */
+    if (!H5F_IS_TMP_ADDR(hdr->f, iblock_addr))
+        cache_flags |= H5AC__FREE_FILE_SPACE_FLAG;
 
 done:
     /* Unprotect the indirect block, with appropriate flags */
@@ -1680,7 +1696,7 @@ H5HF_man_iblock_size(H5F_t *f, hid_t dxpl_id, H5HF_hdr_t *hdr, haddr_t iblock_ad
     HDassert(heap_size);
 
     /* Protect the indirect block */
-    if(NULL == (iblock = H5HF_man_iblock_protect(hdr, dxpl_id, iblock_addr, nrows, par_iblock, par_entry, FALSE, H5AC_READ, &did_protect)))
+    if(NULL == (iblock = H5HF_man_iblock_protect(hdr, dxpl_id, iblock_addr, nrows, par_iblock, par_entry, FALSE, H5AC__READ_ONLY_FLAG, &did_protect)))
         HGOTO_ERROR(H5E_HEAP, H5E_CANTLOAD, FAIL, "unable to load fractal heap indirect block")
 
     /* Accumulate size of this indirect block */
diff --git a/src/H5HFiter.c b/src/H5HFiter.c
index 137d0ee..262a9ee 100644
--- a/src/H5HFiter.c
+++ b/src/H5HFiter.c
@@ -217,7 +217,7 @@ H5HF_man_iter_start_offset(H5HF_hdr_t *hdr, hid_t dxpl_id,
         } /* end else */
 
         /* Load indirect block for this context location */
-        if(NULL == (iblock = H5HF_man_iblock_protect(hdr, dxpl_id, iblock_addr, iblock_nrows, iblock_parent, iblock_par_entry, FALSE, H5AC_WRITE, &did_protect)))
+        if(NULL == (iblock = H5HF_man_iblock_protect(hdr, dxpl_id, iblock_addr, iblock_nrows, iblock_parent, iblock_par_entry, FALSE, H5AC__NO_FLAGS_SET, &did_protect)))
             HGOTO_ERROR(H5E_HEAP, H5E_CANTPROTECT, FAIL, "unable to protect fractal heap indirect block")
 
         /* Make indirect block the context for the current location */
diff --git a/src/H5HFman.c b/src/H5HFman.c
index 58dab10..5f95a91 100644
--- a/src/H5HFman.c
+++ b/src/H5HFman.c
@@ -161,7 +161,7 @@ H5HF_man_insert(H5HF_hdr_t *hdr, hid_t dxpl_id, size_t obj_size, const void *obj
         HGOTO_ERROR(H5E_HEAP, H5E_CANTGET, FAIL, "can't retrieve direct block information")
 
     /* Lock direct block */
-    if(NULL == (dblock = H5HF_man_dblock_protect(hdr, dxpl_id, dblock_addr, dblock_size, sec_node->u.single.parent, sec_node->u.single.par_entry, H5AC_WRITE)))
+    if(NULL == (dblock = H5HF_man_dblock_protect(hdr, dxpl_id, dblock_addr, dblock_size, sec_node->u.single.parent, sec_node->u.single.par_entry, H5AC__NO_FLAGS_SET)))
         HGOTO_ERROR(H5E_HEAP, H5E_CANTPROTECT, FAIL, "unable to load fractal heap direct block")
 
     /* Insert object into block */
@@ -274,7 +274,11 @@ H5HF_man_op_real(H5HF_hdr_t *hdr, hid_t dxpl_id, const uint8_t *id,
     H5HF_operator_t op, void *op_data, unsigned op_flags)
 {
     H5HF_direct_t *dblock = NULL;       /* Pointer to direct block to query */
-    H5AC_protect_t dblock_access;       /* Access method for direct block */
+    unsigned dblock_access_flags;       /* Access method for direct block */
+                                        /* must equal either 
+                                         * H5AC__NO_FLAGS_SET or 
+                                         * H5AC__READ_ONLY_FLAG
+                                         */
     haddr_t dblock_addr;                /* Direct block address */
     size_t dblock_size;                 /* Direct block size */
     unsigned dblock_cache_flags;        /* Flags for unprotecting direct block */
@@ -298,11 +302,11 @@ H5HF_man_op_real(H5HF_hdr_t *hdr, hid_t dxpl_id, const uint8_t *id,
         /* Check pipeline */
         H5HF_MAN_WRITE_CHECK_PLINE(hdr)
 
-        dblock_access = H5AC_WRITE;
+        dblock_access_flags = H5AC__NO_FLAGS_SET;
         dblock_cache_flags = H5AC__DIRTIED_FLAG;
     } /* end if */
     else {
-        dblock_access = H5AC_READ;
+        dblock_access_flags = H5AC__READ_ONLY_FLAG;
         dblock_cache_flags = H5AC__NO_FLAGS_SET;
     } /* end else */
 
@@ -332,7 +336,7 @@ H5HF_man_op_real(H5HF_hdr_t *hdr, hid_t dxpl_id, const uint8_t *id,
         dblock_size = hdr->man_dtable.cparam.start_block_size;
 
         /* Lock direct block */
-        if(NULL == (dblock = H5HF_man_dblock_protect(hdr, dxpl_id, dblock_addr, dblock_size, NULL, 0, dblock_access)))
+        if(NULL == (dblock = H5HF_man_dblock_protect(hdr, dxpl_id, dblock_addr, dblock_size, NULL, 0, dblock_access_flags)))
             HGOTO_ERROR(H5E_HEAP, H5E_CANTPROTECT, FAIL, "unable to protect fractal heap direct block")
     } /* end if */
     else {
@@ -341,7 +345,7 @@ H5HF_man_op_real(H5HF_hdr_t *hdr, hid_t dxpl_id, const uint8_t *id,
         unsigned entry;                 /* Entry of block */
 
         /* Look up indirect block containing direct block */
-        if(H5HF_man_dblock_locate(hdr, dxpl_id, obj_off, &iblock, &entry, &did_protect, H5AC_READ) < 0)
+        if(H5HF_man_dblock_locate(hdr, dxpl_id, obj_off, &iblock, &entry, &did_protect, H5AC__READ_ONLY_FLAG) < 0)
             HGOTO_ERROR(H5E_HEAP, H5E_CANTCOMPUTE, FAIL, "can't compute row & column of section")
 
         /* Set direct block info */
@@ -359,7 +363,7 @@ H5HF_man_op_real(H5HF_hdr_t *hdr, hid_t dxpl_id, const uint8_t *id,
         } /* end if */
 
         /* Lock direct block */
-        if(NULL == (dblock = H5HF_man_dblock_protect(hdr, dxpl_id, dblock_addr, dblock_size, iblock, entry, dblock_access))) {
+        if(NULL == (dblock = H5HF_man_dblock_protect(hdr, dxpl_id, dblock_addr, dblock_size, iblock, entry, dblock_access_flags))) {
             /* Unlock indirect block */
             if(H5HF_man_iblock_unprotect(iblock, dxpl_id, H5AC__NO_FLAGS_SET, did_protect) < 0)
                 HGOTO_ERROR(H5E_HEAP, H5E_CANTUNPROTECT, FAIL, "unable to release fractal heap indirect block")
@@ -578,7 +582,7 @@ H5HF_man_remove(H5HF_hdr_t *hdr, hid_t dxpl_id, const uint8_t *id)
     } /* end if */
     else {
         /* Look up indirect block containing direct block */
-        if(H5HF_man_dblock_locate(hdr, dxpl_id, obj_off, &iblock, &dblock_entry, &did_protect, H5AC_WRITE) < 0)
+        if(H5HF_man_dblock_locate(hdr, dxpl_id, obj_off, &iblock, &dblock_entry, &did_protect, H5AC__NO_FLAGS_SET) < 0)
             HGOTO_ERROR(H5E_HEAP, H5E_CANTCOMPUTE, FAIL, "can't compute row & column of section")
 
         /* Check for offset of invalid direct block */
diff --git a/src/H5HFpkg.h b/src/H5HFpkg.h
index 63c1a3e..4655d83 100644
--- a/src/H5HFpkg.h
+++ b/src/H5HFpkg.h
@@ -341,7 +341,7 @@ typedef struct H5HF_hdr_t {
     size_t      rc;             /* Reference count of heap's components using heap header */
     haddr_t     heap_addr;      /* Address of heap header in the file */
     size_t      heap_size;      /* Size of heap header in the file */
-    H5AC_protect_t mode;        /* Access mode for heap */
+    unsigned    mode;           /* Access mode for heap */
     H5F_t      *f;              /* Pointer to file for heap */
     size_t      file_rc;        /* Reference count of files using heap header */
     hbool_t     pending_delete; /* Heap is pending deletion */
@@ -424,6 +424,31 @@ typedef struct H5HF_direct_t {
     size_t      size;           /* Size of direct block                       */
     hsize_t     file_size;      /* Size of direct block in file (only valid when block's space is being freed) */
     uint8_t     *blk;           /* Pointer to buffer containing block data    */
+    uint8_t	*write_buf;	/* Pointer to buffer containing the block data */
+                                /* in form ready to copy to the metadata       */
+                                /* cache's image buffer.                       */
+                                /*                                             */
+                                /* This field is used by                       */
+                                /* H5HF_cache_dblock_pre_serialize() to pass   */
+                                /* the serialized image of the direct block to */
+                                /* H5HF_cache_dblock_serialize().  It should   */
+                                /* NULL at all other times.                    */
+                                /*                                             */
+                                /* If I/O filters are enabled, the pre-        */
+                                /* the pre-serialize function will allocate    */
+                                /* a buffer, copy the filtered version of the  */
+                                /* direct block image into it, and place the   */
+                                /* base address of the buffer in this field.   */
+                                /* The serialize function must discard this    */
+                                /* buffer after it copies the contents into    */
+                                /* the image buffer provided by the metadata   */
+                                /* cache.                                      */
+                                /*                                             */
+                                /* If I/O filters are not enabled, the         */
+                                /* write_buf field is simply set equal to the  */
+                                /* blk field by the pre-serialize function,    */
+                                /* and back to NULL by the serialize function. */
+    size_t	write_size;     /* size of the buffer pointed to by write_buf. */
 
     /* Stored values */
     hsize_t     block_off;      /* Offset of the block within the heap's address space */
@@ -597,7 +622,7 @@ H5_DLL hsize_t H5HF_dtable_span_size(const H5HF_dtable_t *dtable, unsigned start
 H5_DLL H5HF_hdr_t * H5HF_hdr_alloc(H5F_t *f);
 H5_DLL haddr_t H5HF_hdr_create(H5F_t *f, hid_t dxpl_id, const H5HF_create_t *cparam);
 H5_DLL H5HF_hdr_t *H5HF_hdr_protect(H5F_t *f, hid_t dxpl_id, haddr_t addr,
-    H5AC_protect_t rw);
+    unsigned flags);
 H5_DLL herr_t H5HF_hdr_finish_init_phase1(H5HF_hdr_t *hdr);
 H5_DLL herr_t H5HF_hdr_finish_init_phase2(H5HF_hdr_t *hdr);
 H5_DLL herr_t H5HF_hdr_finish_init(H5HF_hdr_t *hdr);
@@ -638,7 +663,7 @@ H5_DLL herr_t H5HF_man_iblock_create(H5HF_hdr_t *hdr, hid_t dxpl_id,
 H5_DLL H5HF_indirect_t *H5HF_man_iblock_protect(H5HF_hdr_t *hdr, hid_t dxpl_id,
     haddr_t iblock_addr, unsigned iblock_nrows,
     H5HF_indirect_t *par_iblock, unsigned par_entry, hbool_t must_protect,
-    H5AC_protect_t rw, hbool_t *did_protect);
+    unsigned flags, hbool_t *did_protect);
 H5_DLL herr_t H5HF_man_iblock_unprotect(H5HF_indirect_t *iblock, hid_t dxpl_id,
     unsigned cache_flags, hbool_t did_protect);
 H5_DLL herr_t H5HF_man_iblock_attach(H5HF_indirect_t *iblock, unsigned entry,
@@ -664,10 +689,10 @@ H5_DLL herr_t H5HF_man_dblock_destroy(H5HF_hdr_t *hdr, hid_t dxpl_id,
 H5_DLL H5HF_direct_t *H5HF_man_dblock_protect(H5HF_hdr_t *hdr, hid_t dxpl_id,
     haddr_t dblock_addr, size_t dblock_size,
     H5HF_indirect_t *par_iblock, unsigned par_entry,
-    H5AC_protect_t rw);
+    unsigned flags);
 H5_DLL herr_t H5HF_man_dblock_locate(H5HF_hdr_t *hdr, hid_t dxpl_id,
     hsize_t obj_off, H5HF_indirect_t **par_iblock,
-    unsigned *par_entry, hbool_t *par_did_protect, H5AC_protect_t rw);
+    unsigned *par_entry, hbool_t *par_did_protect, unsigned flags);
 H5_DLL herr_t H5HF_man_dblock_delete(H5F_t *f, hid_t dxpl_id, haddr_t dblock_addr,
     hsize_t dblock_size);
 H5_DLL herr_t H5HF_man_dblock_dest(H5HF_direct_t *dblock);
diff --git a/src/H5HFsection.c b/src/H5HFsection.c
index 01a7b4a..c997119 100644
--- a/src/H5HFsection.c
+++ b/src/H5HFsection.c
@@ -555,7 +555,7 @@ H5HF_sect_single_locate_parent(H5HF_hdr_t *hdr, hid_t dxpl_id, hbool_t refresh,
     HDassert(sect);
 
     /* Look up indirect block containing direct blocks for range */
-    if(H5HF_man_dblock_locate(hdr, dxpl_id, sect->sect_info.addr, &sec_iblock, &sec_entry, &did_protect, H5AC_READ) < 0)
+    if(H5HF_man_dblock_locate(hdr, dxpl_id, sect->sect_info.addr, &sec_iblock, &sec_entry, &did_protect, H5AC__READ_ONLY_FLAG) < 0)
         HGOTO_ERROR(H5E_HEAP, H5E_CANTCOMPUTE, FAIL, "can't compute row & column of section")
 
     /* Increment reference count on indirect block that free section is in */
@@ -776,7 +776,7 @@ H5HF_sect_single_full_dblock(H5HF_hdr_t *hdr, hid_t dxpl_id,
             hdr->man_dtable.curr_root_rows > 0) {
         H5HF_direct_t *dblock;          /* Pointer to direct block for section */
 
-        if(NULL == (dblock = H5HF_man_dblock_protect(hdr, dxpl_id, dblock_addr, dblock_size, sect->u.single.parent, sect->u.single.par_entry, H5AC_WRITE)))
+        if(NULL == (dblock = H5HF_man_dblock_protect(hdr, dxpl_id, dblock_addr, dblock_size, sect->u.single.parent, sect->u.single.par_entry, H5AC__NO_FLAGS_SET)))
             HGOTO_ERROR(H5E_HEAP, H5E_CANTPROTECT, FAIL, "unable to load fractal heap direct block")
         HDassert(H5F_addr_eq(dblock->block_off + dblock_overhead, sect->sect_info.addr));
 
@@ -1094,7 +1094,7 @@ H5HF_sect_single_shrink(H5FS_section_info_t **_sect, void H5_ATTR_UNUSED *_udata
     /* (should be a root direct block) */
     HDassert(dblock_addr == hdr->man_dtable.table_addr);
     if(NULL == (dblock = H5HF_man_dblock_protect(hdr, dxpl_id, dblock_addr,
-            dblock_size, (*sect)->u.single.parent, (*sect)->u.single.par_entry, H5AC_WRITE)))
+            dblock_size, (*sect)->u.single.parent, (*sect)->u.single.par_entry, H5AC__NO_FLAGS_SET)))
         HGOTO_ERROR(H5E_HEAP, H5E_CANTPROTECT, FAIL, "unable to load fractal heap direct block")
     HDassert(H5F_addr_eq(dblock->block_off + dblock_size, (*sect)->sect_info.addr + (*sect)->sect_info.size));
 
@@ -1221,7 +1221,7 @@ H5HF_sect_single_valid(const H5FS_section_class_t H5_ATTR_UNUSED *cls, const H5F
                 H5HF_direct_t *dblock;      /* Direct block for section */
 
                 /* Protect the direct block for the section */
-                dblock = H5HF_man_dblock_protect(iblock->hdr, H5AC_dxpl_id, dblock_addr, dblock_size, iblock, sect->u.single.par_entry, H5AC_READ);
+                dblock = H5HF_man_dblock_protect(iblock->hdr, H5AC_dxpl_id, dblock_addr, dblock_size, iblock, sect->u.single.par_entry, H5AC__READ_ONLY_FLAG);
                 HDassert(dblock);
 
                 /* Sanity check settings for section */
@@ -2536,7 +2536,7 @@ H5HF_sect_indirect_init_rows(H5HF_hdr_t *hdr, hid_t dxpl_id,
 
                     /* If the child indirect block's address is defined, protect it */
                     if(H5F_addr_defined(child_iblock_addr)) {
-                        if(NULL == (child_iblock = H5HF_man_iblock_protect(hdr, dxpl_id, child_iblock_addr, child_nrows, sect->u.indirect.u.iblock, curr_entry, FALSE, H5AC_WRITE, &did_protect)))
+                        if(NULL == (child_iblock = H5HF_man_iblock_protect(hdr, dxpl_id, child_iblock_addr, child_nrows, sect->u.indirect.u.iblock, curr_entry, FALSE, H5AC__NO_FLAGS_SET, &did_protect)))
                             HGOTO_ERROR(H5E_HEAP, H5E_CANTPROTECT, FAIL, "unable to protect fractal heap indirect block")
                     } /* end if */
                     else
@@ -2771,7 +2771,7 @@ H5HF_sect_indirect_revive_row(H5HF_hdr_t *hdr, hid_t dxpl_id, H5HF_free_section_
     HDassert(sect->sect_info.state == H5FS_SECT_SERIALIZED);
 
     /* Look up indirect block containing indirect blocks for section */
-    if(H5HF_man_dblock_locate(hdr, dxpl_id, sect->sect_info.addr, &sec_iblock, NULL, &did_protect, H5AC_READ) < 0)
+    if(H5HF_man_dblock_locate(hdr, dxpl_id, sect->sect_info.addr, &sec_iblock, NULL, &did_protect, H5AC__READ_ONLY_FLAG) < 0)
         HGOTO_ERROR(H5E_HEAP, H5E_CANTCOMPUTE, FAIL, "can't compute row & column of section")
 
     /* Increment reference count on indirect block that free section is in */
diff --git a/src/H5HG.c b/src/H5HG.c
index ac8ed8d..46b535d 100644
--- a/src/H5HG.c
+++ b/src/H5HG.c
@@ -246,7 +246,7 @@ done:
  *-------------------------------------------------------------------------
  */
 H5HG_heap_t *
-H5HG_protect(H5F_t *f, hid_t dxpl_id, haddr_t addr, H5AC_protect_t rw)
+H5HG_protect(H5F_t *f, hid_t dxpl_id, haddr_t addr, unsigned flags)
 {
     H5HG_heap_t *heap;          /* Global heap */
     H5HG_heap_t *ret_value;     /* Return value */
@@ -257,8 +257,11 @@ H5HG_protect(H5F_t *f, hid_t dxpl_id, haddr_t addr, H5AC_protect_t rw)
     HDassert(f);
     HDassert(H5F_addr_defined(addr));
 
+    /* only H5AC__READ_ONLY_FLAG may appear in flags */
+    HDassert((flags & (unsigned)(~H5AC__READ_ONLY_FLAG)) == 0);
+
     /* Lock the heap into memory */
-    if(NULL == (heap = (H5HG_heap_t *)H5AC_protect(f, dxpl_id, H5AC_GHEAP, addr, f, rw)))
+    if(NULL == (heap = (H5HG_heap_t *)H5AC_protect(f, dxpl_id, H5AC_GHEAP, addr, f, flags)))
         HGOTO_ERROR(H5E_HEAP, H5E_CANTPROTECT, NULL, "unable to protect global heap")
 
     /* Set the heap's address */
@@ -440,7 +443,7 @@ H5HG_extend(H5F_t *f, hid_t dxpl_id, haddr_t addr, size_t need)
     HDassert(H5F_addr_defined(addr));
 
     /* Protect the heap */
-    if(NULL == (heap = H5HG_protect(f, dxpl_id, addr, H5AC_WRITE)))
+    if(NULL == (heap = H5HG_protect(f, dxpl_id, addr, H5AC__NO_FLAGS_SET)))
         HGOTO_ERROR(H5E_HEAP, H5E_CANTPROTECT, FAIL, "unable to protect global heap")
 
     /* Re-allocate the heap information in memory */
@@ -554,7 +557,7 @@ H5HG_insert(H5F_t *f, hid_t dxpl_id, size_t size, void *obj, H5HG_t *hobj/*out*/
     } /* end if */
     HDassert(H5F_addr_defined(addr));
 
-    if(NULL == (heap = H5HG_protect(f, dxpl_id, addr, H5AC_WRITE)))
+    if(NULL == (heap = H5HG_protect(f, dxpl_id, addr, H5AC__NO_FLAGS_SET)))
         HGOTO_ERROR(H5E_HEAP, H5E_CANTPROTECT, FAIL, "unable to protect global heap")
 
     /* Split the free space to make room for the new object */
@@ -618,7 +621,7 @@ H5HG_read(H5F_t *f, hid_t dxpl_id, H5HG_t *hobj, void *object/*out*/,
     HDassert(hobj);
 
     /* Load the heap */
-    if(NULL == (heap = H5HG_protect(f, dxpl_id, hobj->addr, H5AC_READ)))
+    if(NULL == (heap = H5HG_protect(f, dxpl_id, hobj->addr, H5AC__READ_ONLY_FLAG)))
 	HGOTO_ERROR(H5E_HEAP, H5E_CANTPROTECT, NULL, "unable to protect global heap")
 
     HDassert(hobj->idx < heap->nused);
@@ -692,7 +695,7 @@ H5HG_link(H5F_t *f, hid_t dxpl_id, const H5HG_t *hobj, int adjust)
 	HGOTO_ERROR(H5E_HEAP, H5E_WRITEERROR, FAIL, "no write intent on file")
 
     /* Load the heap */
-    if(NULL == (heap = H5HG_protect(f, dxpl_id, hobj->addr, H5AC_WRITE)))
+    if(NULL == (heap = H5HG_protect(f, dxpl_id, hobj->addr, H5AC__NO_FLAGS_SET)))
         HGOTO_ERROR(H5E_HEAP, H5E_CANTPROTECT, FAIL, "unable to protect global heap")
 
     if(adjust != 0) {
@@ -755,7 +758,7 @@ H5HG_remove (H5F_t *f, hid_t dxpl_id, H5HG_t *hobj)
         HGOTO_ERROR(H5E_HEAP, H5E_WRITEERROR, FAIL, "no write intent on file")
 
     /* Load the heap */
-    if(NULL == (heap = H5HG_protect(f, dxpl_id, hobj->addr, H5AC_WRITE)))
+    if(NULL == (heap = H5HG_protect(f, dxpl_id, hobj->addr, H5AC__NO_FLAGS_SET)))
         HGOTO_ERROR(H5E_HEAP, H5E_CANTPROTECT, FAIL, "unable to protect global heap")
 
     HDassert(hobj->idx < heap->nused);
diff --git a/src/H5HGcache.c b/src/H5HGcache.c
index aac73ed..5c6bee1 100644
--- a/src/H5HGcache.c
+++ b/src/H5HGcache.c
@@ -62,12 +62,14 @@
 /********************/
 
 /* Metadata cache callbacks */
-static H5HG_heap_t *H5HG_load(H5F_t *f, hid_t dxpl_id, haddr_t addr, void *udata);
-static herr_t H5HG_flush(H5F_t *f, hid_t dxpl_id, hbool_t dest, haddr_t addr,
-			 H5HG_heap_t *heap, unsigned H5_ATTR_UNUSED * flags_ptr);
-static herr_t H5HG_dest(H5F_t *f, H5HG_heap_t *heap);
-static herr_t H5HG_clear(H5F_t *f, H5HG_heap_t *heap, hbool_t destroy);
-static herr_t H5HG_size(const H5F_t *f, const H5HG_heap_t *heap, size_t *size_ptr);
+static herr_t H5HG__cache_heap_get_load_size(const void *udata, size_t *image_len);
+static void *H5HG__cache_heap_deserialize(const void *image, size_t len,
+    void *udata, hbool_t *dirty); 
+static herr_t H5HG__cache_heap_image_len(const void *thing, size_t *image_len,
+    hbool_t *compressed_ptr, size_t *compressed_image_len_ptr);
+static herr_t H5HG__cache_heap_serialize(const H5F_t *f, void *image,
+    size_t len, void *thing); 
+static herr_t H5HG__cache_heap_free_icr(void *thing);
 
 
 /*********************/
@@ -76,13 +78,19 @@ static herr_t H5HG_size(const H5F_t *f, const H5HG_heap_t *heap, size_t *size_pt
 
 /* H5HG inherits cache-like properties from H5AC */
 const H5AC_class_t H5AC_GHEAP[1] = {{
-    H5AC_GHEAP_ID,
-    (H5AC_load_func_t)H5HG_load,
-    (H5AC_flush_func_t)H5HG_flush,
-    (H5AC_dest_func_t)H5HG_dest,
-    (H5AC_clear_func_t)H5HG_clear,
-    (H5AC_notify_func_t)NULL,
-    (H5AC_size_func_t)H5HG_size,
+    H5AC_GHEAP_ID,                      /* Metadata client ID */
+    "global heap",                      /* Metadata client name (for debugging) */
+    H5FD_MEM_GHEAP,                     /* File space memory type for client */
+    H5AC__CLASS_SPECULATIVE_LOAD_FLAG,  /* Client class behavior flags */
+    H5HG__cache_heap_get_load_size,     /* 'get_load_size' callback */
+    H5HG__cache_heap_deserialize,       /* 'deserialize' callback */
+    H5HG__cache_heap_image_len,         /* 'image_len' callback */
+    NULL,                               /* 'pre_serialize' callback */
+    H5HG__cache_heap_serialize,         /* 'serialize' callback */
+    NULL,                               /* 'notify' callback */
+    H5HG__cache_heap_free_icr,          /* 'free_icr' callback */
+    NULL,                               /* 'clear' callback */
+    NULL,                               /* 'fsf_size' callback */
 }};
 
 
@@ -98,162 +106,204 @@ const H5AC_class_t H5AC_GHEAP[1] = {{
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5HG_load
+ * Function:    H5HG__cache_heap_get_load_size()
  *
- * Purpose:	Loads a global heap collection from disk.
+ * Purpose:	Return the initial speculative read size to the metadata 
+ *		cache.  This size will be used in the initial attempt to read 
+ *		the global heap.  If this read is too small, the cache will 
+ *		try again with the correct value obtained from 
+ *		H5HG__cache_heap_image_len().
  *
- * Return:	Success:	Ptr to a global heap collection.
+ * Return:      Success:        SUCCEED
+ *              Failure:        FAIL
  *
- *		Failure:	NULL
+ * Programmer:  John Mainzer
+ *              7/27/14
  *
- * Programmer:	Robb Matzke
- *              Friday, March 27, 1998
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+H5HG__cache_heap_get_load_size(const void H5_ATTR_UNUSED *_udata, size_t *image_len)
+{
+    FUNC_ENTER_STATIC_NOERR
+
+    HDassert(image_len);
+
+    *image_len = (size_t)H5HG_MINSIZE;
+
+    FUNC_LEAVE_NOAPI(SUCCEED)
+} /* end H5HG__cache_heap_get_load_size() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:    H5HG__cache_heap_deserialize
+ *
+ * Purpose:	Given a buffer containing the on disk image of the global 
+ *		heap, deserialize it, load its contents into a newly allocated
+ *		instance of H5HG_heap_t, and return a pointer to the new instance.
+ *
+ *		Note that this heap client uses speculative reads.  If the supplied
+ *		buffer is too small, we simply make note of the correct size, and 
+ *		wait for the metadata cache to try again.
+ *
+ * Return:      Success:        Pointer to in core representation
+ *              Failure:        NULL
+ *
+ * Programmer:  John Mainzer
+ *              7/27/14
  *
  *-------------------------------------------------------------------------
  */
-static H5HG_heap_t *
-H5HG_load(H5F_t *f, hid_t dxpl_id, haddr_t addr, void *udata)
+static void *
+H5HG__cache_heap_deserialize(const void *_image, size_t len, void *_udata,
+    hbool_t H5_ATTR_UNUSED *dirty)
 {
-    H5HG_heap_t	*heap = NULL;
-    uint8_t	*p;
-    size_t	nalloc, need;
-    size_t      max_idx = 0;            /* The maximum index seen */
-    H5HG_heap_t	*ret_value = NULL;      /* Return value */
+    H5F_t       *f = (H5F_t *)_udata;   /* File pointer -- obtained from user data */
+    H5HG_heap_t *heap = NULL;   /* New global heap */
+    uint8_t     *image;         /* Pointer to image to decode */
+    void        *ret_value;     /* Return value */
 
-    FUNC_ENTER_NOAPI_NOINIT
+    FUNC_ENTER_STATIC
 
-    /* check arguments */
+    /* Sanity checks */
+    HDassert(_image);
+    HDassert(len >= (size_t)H5HG_MINSIZE);
     HDassert(f);
-    HDassert(H5F_addr_defined(addr));
-    HDassert(udata);
+    HDassert(dirty);
 
-    /* Read the initial 4k page */
+    /* Allocate a new global heap */
     if(NULL == (heap = H5FL_CALLOC(H5HG_heap_t)))
         HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, NULL, "memory allocation failed")
     heap->shared = H5F_SHARED(f);
-    if(NULL == (heap->chunk = H5FL_BLK_MALLOC(gheap_chunk, (size_t)H5HG_MINSIZE)))
+    if(NULL == (heap->chunk = H5FL_BLK_MALLOC(gheap_chunk, len)))
         HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, NULL, "memory allocation failed")
-    if(H5F_block_read(f, H5FD_MEM_GHEAP, addr, (size_t)H5HG_MINSIZE, dxpl_id, heap->chunk) < 0)
-	HGOTO_ERROR(H5E_HEAP, H5E_READERROR, NULL, "unable to read global heap collection")
-    p = heap->chunk;
+
+    /* copy the image buffer into the newly allocate chunk */
+    HDmemcpy(heap->chunk, _image, len);
+
+    image = heap->chunk;
 
     /* Magic number */
-    if(HDmemcmp(p, H5HG_MAGIC, (size_t)H5_SIZEOF_MAGIC))
-	HGOTO_ERROR(H5E_HEAP, H5E_CANTLOAD, NULL, "bad global heap collection signature")
-    p += H5_SIZEOF_MAGIC;
+    if(HDmemcmp(image, H5HG_MAGIC, (size_t)H5_SIZEOF_MAGIC))
+        HGOTO_ERROR(H5E_HEAP, H5E_CANTLOAD, NULL, "bad global heap collection signature")
+    image += H5_SIZEOF_MAGIC;
 
     /* Version */
-    if(H5HG_VERSION != *p++)
-	HGOTO_ERROR(H5E_HEAP, H5E_CANTLOAD, NULL, "wrong version number in global heap")
+    if(H5HG_VERSION != *image++) 
+        HGOTO_ERROR(H5E_HEAP, H5E_CANTLOAD, NULL, "wrong version number in global heap")
 
     /* Reserved */
-    p += 3;
+    image += 3;
 
     /* Size */
-    H5F_DECODE_LENGTH(f, p, heap->size);
+    H5F_DECODE_LENGTH(f, image, heap->size);
     HDassert(heap->size >= H5HG_MINSIZE);
-
-    /*
-     * If we didn't read enough in the first try, then read the rest of the
-     * collection now.
-     */
-    if(heap->size > H5HG_MINSIZE) {
-	haddr_t next_addr = addr + (hsize_t)H5HG_MINSIZE;
-
-	if(NULL == (heap->chunk = H5FL_BLK_REALLOC(gheap_chunk, heap->chunk, heap->size)))
-	    HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, NULL, "memory allocation failed")
-	if(H5F_block_read(f, H5FD_MEM_GHEAP, next_addr, (heap->size - H5HG_MINSIZE), dxpl_id, heap->chunk + H5HG_MINSIZE) < 0)
-	    HGOTO_ERROR(H5E_HEAP, H5E_READERROR, NULL, "unable to read global heap collection")
-    } /* end if */
-
-    /* Decode each object */
-    p = heap->chunk + H5HG_SIZEOF_HDR(f);
-    nalloc = H5HG_NOBJS(f, heap->size);
-
-    /* Calloc the obj array because the file format spec makes no guarantee
-     * about the order of the objects, and unused slots must be set to zero.
-     */
-    if(NULL == (heap->obj = H5FL_SEQ_CALLOC(H5HG_obj_t, nalloc)))
-	HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, NULL, "memory allocation failed")
-
-    heap->nalloc = nalloc;
-    while(p < (heap->chunk + heap->size)) {
-	if((p + H5HG_SIZEOF_OBJHDR(f)) > (heap->chunk + heap->size)) {
-	    /*
-	     * The last bit of space is too tiny for an object header, so we
-	     * assume that it's free space.
-	     */
-	    HDassert(NULL == heap->obj[0].begin);
-	    heap->obj[0].size = (size_t)(((const uint8_t *)heap->chunk + heap->size) - p);
-	    heap->obj[0].begin = p;
-	    p += heap->obj[0].size;
-	} /* end if */
-        else {
-	    unsigned idx;
-	    uint8_t *begin = p;
-
-	    UINT16DECODE(p, idx);
-
-            /* Check if we need more room to store heap objects */
-            if(idx >= heap->nalloc) {
-                size_t new_alloc;       /* New allocation number */
-                H5HG_obj_t *new_obj;	/* New array of object descriptions */
-
-                /* Determine the new number of objects to index */
-                new_alloc = MAX(heap->nalloc * 2, (idx + 1));
-                HDassert(idx < new_alloc);
-
-                /* Reallocate array of objects */
-                if(NULL == (new_obj = H5FL_SEQ_REALLOC(H5HG_obj_t, heap->obj, new_alloc)))
-                    HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, NULL, "memory allocation failed")
-
-                /* Clear newly allocated space */
-                HDmemset(&new_obj[heap->nalloc], 0, (new_alloc - heap->nalloc) * sizeof(heap->obj[0]));
-
-                /* Update heap information */
-                heap->nalloc = new_alloc;
-                heap->obj = new_obj;
-                HDassert(heap->nalloc > heap->nused);
+    HDassert((len == H5HG_MINSIZE) /* first try */ || 
+             ((len == heap->size) && (len > H5HG_MINSIZE))); /* second try */
+    
+    if(len == heap->size) {     /* proceed with the deserialize */
+        size_t       max_idx = 0;
+        size_t       nalloc;
+
+        /* Decode each object */
+        image = heap->chunk + H5HG_SIZEOF_HDR(f);
+        nalloc = H5HG_NOBJS(f, heap->size);
+
+        /* Calloc the obj array because the file format spec makes no guarantee
+         * about the order of the objects, and unused slots must be set to zero.
+         */
+        if(NULL == (heap->obj = H5FL_SEQ_CALLOC(H5HG_obj_t, nalloc)))
+            HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, NULL, "memory allocation failed")
+        heap->nalloc = nalloc;
+
+        while(image < (heap->chunk + heap->size)) {
+            if((image + H5HG_SIZEOF_OBJHDR(f)) > (heap->chunk + heap->size)) {
+                /*
+                 * The last bit of space is too tiny for an object header, so
+                 * we assume that it's free space.
+                 */
+                HDassert(NULL == heap->obj[0].begin);
+                heap->obj[0].size = (size_t)(((const uint8_t *)heap->chunk + heap->size) - image);
+                heap->obj[0].begin = image;
+                image += heap->obj[0].size;
             } /* end if */
-
-	    UINT16DECODE(p, heap->obj[idx].nrefs);
-	    p += 4; /*reserved*/
-	    H5F_DECODE_LENGTH(f, p, heap->obj[idx].size);
-	    heap->obj[idx].begin = begin;
-
-	    /*
-	     * The total storage size includes the size of the object header
-	     * and is zero padded so the next object header is properly
-	     * aligned. The entire obj array was calloc'ed, so no need to zero
-	     * the space here. The last bit of space is the free space object
-	     * whose size is never padded and already includes the object
-	     * header.
-	     */
-	    if(idx > 0) {
-		need = H5HG_SIZEOF_OBJHDR(f) + H5HG_ALIGN(heap->obj[idx].size);
-
-                if(idx > max_idx)
-                    max_idx = idx;
-	    } /* end if */
-            else
-		need = heap->obj[idx].size;
-	    p = begin + need;
-	} /* end else */
-    } /* end while */
-    HDassert(p == heap->chunk + heap->size);
-    HDassert(H5HG_ISALIGNED(heap->obj[0].size));
-
-    /* Set the next index value to use */
-    if(max_idx > 0)
-        heap->nused = max_idx + 1;
+            else {
+                size_t need;
+                unsigned idx;
+                uint8_t *begin = image;
+
+                UINT16DECODE(image, idx);
+
+                /* Check if we need more room to store heap objects */
+                if(idx >= heap->nalloc) {
+                    size_t new_alloc;       /* New allocation number */
+                    H5HG_obj_t *new_obj;    /* New array of object   descriptions          */
+
+                    /* Determine the new number of objects to index */
+                    new_alloc = MAX(heap->nalloc * 2, (idx + 1));
+                    HDassert(idx < new_alloc);
+
+                    /* Reallocate array of objects */
+                    if(NULL == (new_obj = H5FL_SEQ_REALLOC(H5HG_obj_t, heap->obj, new_alloc)))
+                        HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, NULL, "memory allocation failed")
+
+                    /* Clear newly allocated space */
+                    HDmemset(&new_obj[heap->nalloc], 0, (new_alloc - heap->nalloc) * sizeof(heap->obj[0]));
+
+                    /* Update heap information */
+                    heap->nalloc = new_alloc;
+                    heap->obj = new_obj;
+                    HDassert(heap->nalloc > heap->nused);
+                } /* end if */
+
+                UINT16DECODE(image, heap->obj[idx].nrefs);
+                image += 4; /*reserved*/
+                H5F_DECODE_LENGTH(f, image, heap->obj[idx].size);
+                heap->obj[idx].begin = begin;
+
+                /*
+                 * The total storage size includes the size of the object 
+                 * header and is zero padded so the next object header is 
+                 * properly aligned. The entire obj array was calloc'ed, 
+                 * so no need to zero the space here. The last bit of space 
+                 * is the free space object whose size is never padded and 
+                 * already includes the object header.
+                 */
+                if(idx > 0) {
+                    need = H5HG_SIZEOF_OBJHDR(f) + H5HG_ALIGN(heap->obj[idx].size);
+                    if(idx > max_idx)
+                        max_idx = idx;
+                } /* end if */
+                else
+                    need = heap->obj[idx].size;
+
+                image = begin + need;
+            } /* end else */
+        } /* end while */
+
+        HDassert(image == heap->chunk + heap->size);
+        HDassert(H5HG_ISALIGNED(heap->obj[0].size));
+
+        /* Set the next index value to use */
+        if(max_idx > 0)
+            heap->nused = max_idx + 1;
+        else
+            heap->nused = 1;
+
+        HDassert(max_idx < heap->nused);
+
+        /* Add the new heap to the CWFS list for the file */
+        if(H5F_cwfs_add(f, heap) < 0)
+            HGOTO_ERROR(H5E_HEAP, H5E_CANTINIT, NULL, "unable to add global heap collection to file's CWFS")
+    } /* end if ( len == heap->size ) */
     else
-        heap->nused = 1;
-
-    HDassert(max_idx < heap->nused);
-
-    /* Add the new heap to the CWFS list for the file */
-    if(H5F_cwfs_add(f, heap) < 0)
-	HGOTO_ERROR(H5E_HEAP, H5E_CANTINIT, NULL, "unable to add global heap collection to file's CWFS")
+        /* if len is less than heap size, then the initial speculative 
+         * read was too small.  In this case we return without reporting
+         * failure.  H5C_load_entry() will call H5HG__cache_heap_image_len()
+         * to get the actual read size, and then repeat the read with the 
+         * correct size, and call this function a second time.
+         */
+        HDassert(len < heap->size);
 
     ret_value = heap;
 
@@ -263,154 +313,126 @@ done:
             HDONE_ERROR(H5E_HEAP, H5E_CANTFREE, NULL, "unable to destroy global heap collection")
 
     FUNC_LEAVE_NOAPI(ret_value)
-} /* end H5HG_load() */
+} /* end H5HG__cache_heap_deserialize() */
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5HG_flush
+ * Function:    H5HG__cache_heap_image_len
  *
- * Purpose:	Flushes a global heap collection from memory to disk if it's
- *		dirty.  Optionally deletes teh heap from memory.
+ * Purpose:	Return the on disk image size of the global heap to the 
+ *		metadata cache via the image_len.
  *
- * Return:	Non-negative on success/Negative on failure
+ * Return:      Success:        SUCCEED
+ *              Failure:        FAIL
  *
- * Programmer:	Robb Matzke
- *              Friday, March 27, 1998
+ * Programmer:  John Mainzer
+ *              7/27/14
  *
  *-------------------------------------------------------------------------
  */
 static herr_t
-H5HG_flush(H5F_t *f, hid_t dxpl_id, hbool_t destroy, haddr_t addr, H5HG_heap_t *heap, unsigned H5_ATTR_UNUSED * flags_ptr)
+H5HG__cache_heap_image_len(const void *_thing, size_t *image_len, 
+    hbool_t H5_ATTR_UNUSED *compressed_ptr, size_t H5_ATTR_UNUSED *compressed_image_len_ptr)
 {
-    herr_t ret_value = SUCCEED;       /* Return value */
+    const H5HG_heap_t *heap = (const H5HG_heap_t *)_thing;
 
-    FUNC_ENTER_NOAPI_NOINIT
+    FUNC_ENTER_STATIC_NOERR
 
-    /* Check arguments */
-    HDassert(f);
-    HDassert(H5F_addr_defined(addr));
-    HDassert(H5F_addr_eq(addr, heap->addr));
+    /* Sanity checks */
     HDassert(heap);
+    HDassert(heap->cache_info.magic == H5C__H5C_CACHE_ENTRY_T_MAGIC);
+    HDassert(heap->cache_info.type == H5AC_GHEAP);
+    HDassert(heap->size >= H5HG_MINSIZE);
+    HDassert(image_len);
 
-    if(heap->cache_info.is_dirty) {
-	if(H5F_block_write(f, H5FD_MEM_GHEAP, addr, heap->size, dxpl_id, heap->chunk) < 0)
-	    HGOTO_ERROR(H5E_HEAP, H5E_WRITEERROR, FAIL, "unable to write global heap collection to file")
-	heap->cache_info.is_dirty = FALSE;
-    } /* end if */
+    *image_len = heap->size;
 
-    if(destroy)
-        if(H5HG_dest(f, heap) < 0)
-	    HGOTO_ERROR(H5E_HEAP, H5E_CANTFREE, FAIL, "unable to destroy global heap collection")
+    FUNC_LEAVE_NOAPI(SUCCEED)
+} /* end H5HG__cache_heap_image_len() */
 
-done:
-    FUNC_LEAVE_NOAPI(ret_value)
-} /* end H5HG_flush() */
+/**************************************/
+/* no H5HG_cache_heap_pre_serialize() */
+/**************************************/
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5HG_dest
+ * Function:    H5HG__cache_heap_serialize
+ *
+ * Purpose:	Given an appropriately sized buffer and an instance of 
+ *		H5HG_heap_t, serialize the global heap for writing to file,
+ *		and copy the serialized verion into the buffer.
  *
- * Purpose:	Destroys a global heap collection in memory
  *
- * Return:	Non-negative on success/Negative on failure
+ * Return:      Success:        SUCCEED
+ *              Failure:        FAIL
  *
- * Programmer:	Quincey Koziol
- *              Wednesday, January 15, 2003
+ * Programmer:  John Mainzer
+ *              7/27/14
  *
  *-------------------------------------------------------------------------
  */
 static herr_t
-H5HG_dest(H5F_t *f, H5HG_heap_t *heap)
+H5HG__cache_heap_serialize(const H5F_t *f, void *image, size_t len,
+    void *_thing)
 {
-    herr_t ret_value = SUCCEED;         /* Return value */
+    H5HG_heap_t *heap = (H5HG_heap_t *)_thing;
 
-    FUNC_ENTER_NOAPI_NOINIT
+    FUNC_ENTER_STATIC_NOERR
 
-    /* Check arguments */
+    HDassert(f);
+    HDassert(image);
     HDassert(heap);
+    HDassert(heap->cache_info.magic == H5C__H5C_CACHE_ENTRY_T_MAGIC);
+    HDassert(heap->cache_info.type == H5AC_GHEAP);
+    HDassert(heap->size == len);
+    HDassert(heap->chunk);
 
-    /* Verify that node is clean */
-    HDassert(heap->cache_info.is_dirty == FALSE);
+    /* copy the image into the buffer */
+    HDmemcpy(image, heap->chunk, len);
 
-    /* If we're going to free the space on disk, the address must be valid */
-    HDassert(!heap->cache_info.free_file_space_on_destroy || H5F_addr_defined(heap->cache_info.addr));
-
-    /* Check for freeing file space for globalheap */
-    if(heap->cache_info.free_file_space_on_destroy) {
-        /* Release the space on disk */
-        /* (XXX: Nasty usage of internal DXPL value! -QAK) */
-        if(H5MF_xfree(f, H5FD_MEM_GHEAP, H5AC_dxpl_id, heap->cache_info.addr, (hsize_t)heap->size) < 0)
-            HGOTO_ERROR(H5E_BTREE, H5E_CANTFREE, FAIL, "unable to free global heap")
-    } /* end if */
-
-    /* Destroy global heap collection */
-    if(H5HG_free(heap) < 0)
-        HGOTO_ERROR(H5E_HEAP, H5E_CANTFREE, FAIL, "unable to destroy global heap collection")
+    FUNC_LEAVE_NOAPI(SUCCEED)
+} /* end H5HG__cache_heap_serialize() */
 
-done:
-    FUNC_LEAVE_NOAPI(ret_value)
-} /* H5HG_dest() */
+/****************************************/
+/* no H5HG_cache_heap_notify() function */
+/****************************************/
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5HG_clear
+ * Function:    H5HG__cache_heap_free_icr
  *
- * Purpose:	Mark a global heap in memory as non-dirty.
+ * Purpose:	Free the in memory representation of the supplied global heap.
  *
- * Return:	Non-negative on success/Negative on failure
+ * Note:	The metadata cache sets the object's cache_info.magic to
+ *		H5C__H5C_CACHE_ENTRY_T_BAD_MAGIC before calling a free_icr
+ *		callback (checked in assert).
  *
- * Programmer:	Quincey Koziol
- *              Thursday, March 20, 2003
+ * Return:      Success:        SUCCEED
+ *              Failure:        FAIL
+ *
+ * Programmer:  John Mainzer
+ *              7/27/14
  *
  *-------------------------------------------------------------------------
  */
 static herr_t
-H5HG_clear(H5F_t *f, H5HG_heap_t *heap, hbool_t destroy)
+H5HG__cache_heap_free_icr(void *_thing)
 {
+    H5HG_heap_t *heap = (H5HG_heap_t *)_thing;
     herr_t      ret_value = SUCCEED;    /* Return value */
 
-    FUNC_ENTER_NOAPI_NOINIT
+    FUNC_ENTER_STATIC
 
     /* Sanity checks */
     HDassert(heap);
+    HDassert(heap->cache_info.magic == H5C__H5C_CACHE_ENTRY_T_BAD_MAGIC);
+    HDassert(heap->cache_info.type == H5AC_GHEAP);
 
-    /* Mark heap as clean */
-    heap->cache_info.is_dirty = FALSE;
-
-    if(destroy)
-        if(H5HG_dest(f, heap) < 0)
-	    HGOTO_ERROR(H5E_HEAP, H5E_CANTFREE, FAIL, "unable to destroy global heap collection")
+    /* Destroy global heap collection */
+    if(H5HG_free(heap) < 0)
+        HGOTO_ERROR(H5E_HEAP, H5E_CANTFREE, FAIL, "unable to destroy global heap collection")
 
 done:
     FUNC_LEAVE_NOAPI(ret_value)
-} /* H5HG_clear() */
-
-
-/*-------------------------------------------------------------------------
- * Function:	H5HG_size
- *
- * Purpose:	Compute the size in bytes of the specified instance of
- *              H5HG_heap_t on disk, and return it in *len_ptr.  On failure,
- *              the value of *len_ptr is undefined.
- *
- * Return:	Non-negative on success/Negative on failure
- *
- * Programmer:	John Mainzer
- *              5/13/04
- *
- *-------------------------------------------------------------------------
- */
-static herr_t
-H5HG_size(const H5F_t H5_ATTR_UNUSED *f, const H5HG_heap_t *heap, size_t *size_ptr)
-{
-    FUNC_ENTER_NOAPI_NOINIT_NOERR
-
-    /* Check arguments */
-    HDassert(heap);
-    HDassert(size_ptr);
-
-    *size_ptr = heap->size;
-
-    FUNC_LEAVE_NOAPI(SUCCEED)
-} /* H5HG_size() */
+} /* end H5HG__cache_heap_free_icr() */
 
diff --git a/src/H5HGdbg.c b/src/H5HGdbg.c
index 16d8c49..c79aac8 100644
--- a/src/H5HGdbg.c
+++ b/src/H5HGdbg.c
@@ -103,7 +103,7 @@ H5HG_debug(H5F_t *f, hid_t dxpl_id, haddr_t addr, FILE *stream, int indent,
     HDassert(indent >= 0);
     HDassert(fwidth >= 0);
 
-    if(NULL == (h = H5HG_protect(f, dxpl_id, addr, H5AC_READ)))
+    if(NULL == (h = H5HG_protect(f, dxpl_id, addr, H5AC__READ_ONLY_FLAG)))
         HGOTO_ERROR(H5E_HEAP, H5E_CANTPROTECT, FAIL, "unable to protect global heap collection");
 
     HDfprintf(stream, "%*sGlobal Heap Collection...\n", indent, "");
diff --git a/src/H5HGpkg.h b/src/H5HGpkg.h
index f3546a2..9137e7b 100644
--- a/src/H5HGpkg.h
+++ b/src/H5HGpkg.h
@@ -143,7 +143,7 @@ struct H5HG_heap_t {
 /* Package Private Prototypes */
 /******************************/
 H5_DLL herr_t H5HG_free(H5HG_heap_t *heap);
-H5_DLL H5HG_heap_t *H5HG_protect(H5F_t *f, hid_t dxpl_id, haddr_t addr, H5AC_protect_t rw);
+H5_DLL H5HG_heap_t *H5HG_protect(H5F_t *f, hid_t dxpl_id, haddr_t addr, unsigned flags);
 
 #endif /* _H5HGpkg_H */
 
diff --git a/src/H5HL.c b/src/H5HL.c
index b1b5b24..eae0482 100644
--- a/src/H5HL.c
+++ b/src/H5HL.c
@@ -441,7 +441,7 @@ done:
  *-------------------------------------------------------------------------
  */
 H5HL_t *
-H5HL_protect(H5F_t *f, hid_t dxpl_id, haddr_t addr, H5AC_protect_t rw)
+H5HL_protect(H5F_t *f, hid_t dxpl_id, haddr_t addr, unsigned flags)
 {
     H5HL_cache_prfx_ud_t prfx_udata; /* User data for protecting local heap prefix */
     H5HL_prfx_t *prfx = NULL;   /* Local heap prefix */
@@ -457,14 +457,19 @@ H5HL_protect(H5F_t *f, hid_t dxpl_id, haddr_t addr, H5AC_protect_t rw)
     HDassert(f);
     HDassert(H5F_addr_defined(addr));
 
+    /* only the H5AC__READ_ONLY_FLAG may appear in flags */
+    HDassert((flags & (unsigned)(~H5AC__READ_ONLY_FLAG)) == 0);
+
     /* Construct the user data for protect callback */
+    prfx_udata.made_attempt = FALSE;
     prfx_udata.sizeof_size = H5F_SIZEOF_SIZE(f);
     prfx_udata.sizeof_addr = H5F_SIZEOF_ADDR(f);
     prfx_udata.prfx_addr = addr;
     prfx_udata.sizeof_prfx = H5HL_SIZEOF_HDR(f);
+    prfx_udata.loaded = FALSE;
 
     /* Protect the local heap prefix */
-    if(NULL == (prfx = (H5HL_prfx_t *)H5AC_protect(f, dxpl_id, H5AC_LHEAP_PRFX, addr, &prfx_udata, rw)))
+    if(NULL == (prfx = (H5HL_prfx_t *)H5AC_protect(f, dxpl_id, H5AC_LHEAP_PRFX, addr, &prfx_udata, flags)))
         HGOTO_ERROR(H5E_HEAP, H5E_CANTPROTECT, NULL, "unable to load heap prefix")
 
     /* Get the pointer to the heap */
@@ -486,7 +491,7 @@ H5HL_protect(H5F_t *f, hid_t dxpl_id, haddr_t addr, H5AC_protect_t rw)
             dblk_udata.loaded = FALSE;
 
             /* Protect the local heap data block */
-            if(NULL == (dblk = (H5HL_dblk_t *)H5AC_protect(f, dxpl_id, H5AC_LHEAP_DBLK, heap->dblk_addr, &dblk_udata, rw)))
+            if(NULL == (dblk = (H5HL_dblk_t *)H5AC_protect(f, dxpl_id, H5AC_LHEAP_DBLK, heap->dblk_addr, &dblk_udata, flags)))
                 HGOTO_ERROR(H5E_HEAP, H5E_CANTPROTECT, NULL, "unable to load heap data block")
 
             /* Pin the prefix, if the data block was loaded from file */
@@ -1071,13 +1076,15 @@ H5HL_delete(H5F_t *f, hid_t dxpl_id, haddr_t addr)
     HDassert(H5F_addr_defined(addr));
 
     /* Construct the user data for protect callback */
+    prfx_udata.made_attempt = FALSE;
     prfx_udata.sizeof_size = H5F_SIZEOF_SIZE(f);
     prfx_udata.sizeof_addr = H5F_SIZEOF_ADDR(f);
     prfx_udata.prfx_addr = addr;
     prfx_udata.sizeof_prfx = H5HL_SIZEOF_HDR(f);
+    prfx_udata.loaded = FALSE;
 
     /* Protect the local heap prefix */
-    if(NULL == (prfx = (H5HL_prfx_t *)H5AC_protect(f, dxpl_id, H5AC_LHEAP_PRFX, addr, &prfx_udata, H5AC_WRITE)))
+    if(NULL == (prfx = (H5HL_prfx_t *)H5AC_protect(f, dxpl_id, H5AC_LHEAP_PRFX, addr, &prfx_udata, H5AC__NO_FLAGS_SET)))
         HGOTO_ERROR(H5E_HEAP, H5E_CANTPROTECT, FAIL, "unable to load heap prefix")
 
     /* Get the pointer to the heap */
@@ -1092,7 +1099,7 @@ H5HL_delete(H5F_t *f, hid_t dxpl_id, haddr_t addr)
         dblk_udata.loaded = FALSE;
 
         /* Protect the local heap data block */
-        if(NULL == (dblk = (H5HL_dblk_t *)H5AC_protect(f, dxpl_id, H5AC_LHEAP_DBLK, heap->dblk_addr, &dblk_udata, H5AC_WRITE)))
+        if(NULL == (dblk = (H5HL_dblk_t *)H5AC_protect(f, dxpl_id, H5AC_LHEAP_DBLK, heap->dblk_addr, &dblk_udata, H5AC__NO_FLAGS_SET)))
             HGOTO_ERROR(H5E_HEAP, H5E_CANTPROTECT, FAIL, "unable to load heap data block")
 
         /* Pin the prefix, if the data block was loaded from file */
@@ -1147,13 +1154,15 @@ H5HL_get_size(H5F_t *f, hid_t dxpl_id, haddr_t addr, size_t *size)
     HDassert(size);
 
     /* Construct the user data for protect callback */
+    prfx_udata.made_attempt = FALSE;
     prfx_udata.sizeof_size = H5F_SIZEOF_SIZE(f);
     prfx_udata.sizeof_addr = H5F_SIZEOF_ADDR(f);
     prfx_udata.prfx_addr = addr;
     prfx_udata.sizeof_prfx = H5HL_SIZEOF_HDR(f);
+    prfx_udata.loaded = FALSE;
 
     /* Protect the local heap prefix */
-    if(NULL == (prfx = (H5HL_prfx_t *)H5AC_protect(f, dxpl_id, H5AC_LHEAP_PRFX, addr, &prfx_udata, H5AC_READ)))
+    if(NULL == (prfx = (H5HL_prfx_t *)H5AC_protect(f, dxpl_id, H5AC_LHEAP_PRFX, addr, &prfx_udata, H5AC__READ_ONLY_FLAG)))
         HGOTO_ERROR(H5E_HEAP, H5E_CANTPROTECT, FAIL, "unable to load heap prefix")
 
     /* Get the pointer to the heap */
@@ -1199,13 +1208,15 @@ H5HL_heapsize(H5F_t *f, hid_t dxpl_id, haddr_t addr, hsize_t *heap_size)
     HDassert(heap_size);
 
     /* Construct the user data for protect callback */
+    prfx_udata.made_attempt = FALSE;
     prfx_udata.sizeof_size = H5F_SIZEOF_SIZE(f);
     prfx_udata.sizeof_addr = H5F_SIZEOF_ADDR(f);
     prfx_udata.prfx_addr = addr;
     prfx_udata.sizeof_prfx = H5HL_SIZEOF_HDR(f);
+    prfx_udata.loaded = FALSE;
 
     /* Protect the local heap prefix */
-    if(NULL == (prfx = (H5HL_prfx_t *)H5AC_protect(f, dxpl_id, H5AC_LHEAP_PRFX, addr, &prfx_udata, H5AC_READ)))
+    if(NULL == (prfx = (H5HL_prfx_t *)H5AC_protect(f, dxpl_id, H5AC_LHEAP_PRFX, addr, &prfx_udata, H5AC__READ_ONLY_FLAG)))
         HGOTO_ERROR(H5E_HEAP, H5E_CANTPROTECT, FAIL, "unable to load heap prefix")
 
     /* Get the pointer to the heap */
diff --git a/src/H5HLcache.c b/src/H5HLcache.c
index b2c764d..17ded00 100644
--- a/src/H5HLcache.c
+++ b/src/H5HLcache.c
@@ -69,18 +69,26 @@
 /********************/
 
 /* Metadata cache callbacks */
-static void *H5HL_prefix_load(H5F_t *f, hid_t dxpl_id, haddr_t addr, void *udata);
-static herr_t H5HL_prefix_flush(H5F_t *f, hid_t dxpl_id, hbool_t dest, haddr_t addr,
-    void *thing, unsigned *flags_ptr);
-static herr_t H5HL_prefix_dest(H5F_t *f, void *thing);
-static herr_t H5HL_prefix_clear(H5F_t *f, void *thing, hbool_t destroy);
-static herr_t H5HL_prefix_size(const H5F_t *f, const void *thing, size_t *size_ptr);
-static void *H5HL_datablock_load(H5F_t *f, hid_t dxpl_id, haddr_t addr, void *udata);
-static herr_t H5HL_datablock_flush(H5F_t *f, hid_t dxpl_id, hbool_t dest, haddr_t addr,
-    void *thing, unsigned *flags_ptr);
-static herr_t H5HL_datablock_dest(H5F_t *f, void *thing);
-static herr_t H5HL_datablock_clear(H5F_t *f, void *thing, hbool_t destroy);
-static herr_t H5HL_datablock_size(const H5F_t *f, const void *thing, size_t *size_ptr);
+static herr_t H5HL__cache_prefix_get_load_size(const void *udata, size_t *image_len);
+static void *H5HL__cache_prefix_deserialize(const void *image, size_t len,
+    void *udata, hbool_t *dirty);
+static herr_t H5HL__cache_prefix_image_len(const void *thing, 
+    size_t *image_len, hbool_t *compressed_ptr, 
+    size_t *compressed_image_len_ptr);
+static herr_t H5HL__cache_prefix_serialize(const H5F_t *f, void *image,
+    size_t len, void *thing); 
+static herr_t H5HL__cache_prefix_free_icr(void *thing);
+
+static herr_t H5HL__cache_datablock_get_load_size(const void *udata,
+    size_t *image_len); 
+static void *H5HL__cache_datablock_deserialize(const void *image, size_t len,
+    void *udata, hbool_t *dirty); 
+static herr_t H5HL__cache_datablock_image_len(const void *thing, 
+    size_t *image_len, hbool_t *compressed_ptr, 
+    size_t *compressed_image_len_ptr);
+static herr_t H5HL__cache_datablock_serialize(const H5F_t *f, void *image,
+    size_t len, void *thing); 
+static herr_t H5HL__cache_datablock_free_icr(void *thing);
 
 
 /*********************/
@@ -89,23 +97,35 @@ static herr_t H5HL_datablock_size(const H5F_t *f, const void *thing, size_t *siz
 
 /* H5HL inherits cache-like properties from H5AC */
 const H5AC_class_t H5AC_LHEAP_PRFX[1] = {{
-    H5AC_LHEAP_PRFX_ID,
-    H5HL_prefix_load,
-    H5HL_prefix_flush,
-    H5HL_prefix_dest,
-    H5HL_prefix_clear,
-    NULL,
-    H5HL_prefix_size,
+    H5AC_LHEAP_PRFX_ID,                 /* Metadata client ID */
+    "local heap prefix",                /* Metadata client name (for debugging) */
+    H5FD_MEM_LHEAP,                     /* File space memory type for client */
+    H5AC__CLASS_SPECULATIVE_LOAD_FLAG,  /* Client class behavior flags */
+    H5HL__cache_prefix_get_load_size,   /* 'get_load_size' callback */
+    H5HL__cache_prefix_deserialize,     /* 'deserialize' callback */
+    H5HL__cache_prefix_image_len,       /* 'image_len' callback */
+    NULL,                               /* 'pre_serialize' callback */
+    H5HL__cache_prefix_serialize,       /* 'serialize' callback */
+    NULL,                               /* 'notify' callback */
+    H5HL__cache_prefix_free_icr,        /* 'free_icr' callback */
+    NULL,                               /* 'clear' callback */
+    NULL,                               /* 'fsf_size' callback */
 }};
 
 const H5AC_class_t H5AC_LHEAP_DBLK[1] = {{
-    H5AC_LHEAP_DBLK_ID,
-    H5HL_datablock_load,
-    H5HL_datablock_flush,
-    H5HL_datablock_dest,
-    H5HL_datablock_clear,
-    NULL,
-    H5HL_datablock_size,
+    H5AC_LHEAP_DBLK_ID,                 /* Metadata client ID */
+    "local heap datablock",             /* Metadata client name (for debugging) */
+    H5FD_MEM_LHEAP,                     /* File space memory type for client */
+    H5AC__CLASS_NO_FLAGS_SET,           /* Client class behavior flags */
+    H5HL__cache_datablock_get_load_size,/* 'get_load_size' callback */
+    H5HL__cache_datablock_deserialize,  /* 'deserialize' callback */
+    H5HL__cache_datablock_image_len,    /* 'image_len' callback */
+    NULL,                               /* 'pre_serialize' callback */
+    H5HL__cache_datablock_serialize,    /* 'serialize' callback */
+    NULL,                               /* 'notify' callback */
+    H5HL__cache_datablock_free_icr,     /* 'free_icr' callback */
+    NULL,                               /* 'clear' callback */
+    NULL,                               /* 'fsf_size' callback */
 }};
 
 
@@ -149,7 +169,7 @@ H5HL__fl_deserialize(H5HL_t *heap)
     /* Build free list */
     free_block = heap->free_block;
     while(H5HL_FREE_NULL != free_block) {
-        const uint8_t *p;               /* Pointer into image buffer */
+        const uint8_t *image;           /* Pointer into image buffer */
 
         /* Sanity check */
         if(free_block >= heap->dblk_size)
@@ -163,13 +183,13 @@ H5HL__fl_deserialize(H5HL_t *heap)
         fl->next = NULL;
 
         /* Decode offset of next free block */
-        p = heap->dblk_image + free_block;
-        H5F_DECODE_LENGTH_LEN(p, free_block, heap->sizeof_size);
+        image = heap->dblk_image + free_block;
+        H5F_DECODE_LENGTH_LEN(image, free_block, heap->sizeof_size);
         if(free_block == 0)
             HGOTO_ERROR(H5E_HEAP, H5E_BADVALUE, FAIL, "free block size is zero?")
 
         /* Decode length of this free block */
-        H5F_DECODE_LENGTH_LEN(p, fl->size, heap->sizeof_size);
+        H5F_DECODE_LENGTH_LEN(image, fl->size, heap->sizeof_size);
         if((fl->offset + fl->size) > heap->dblk_size)
             HGOTO_ERROR(H5E_HEAP, H5E_BADRANGE, FAIL, "bad heap free list")
 
@@ -217,17 +237,17 @@ H5HL__fl_serialize(const H5HL_t *heap)
 
     /* Serialize the free list into the heap data's image */
     for(fl = heap->freelist; fl; fl = fl->next) {
-        uint8_t     *p;                     /* Pointer into raw data buffer */
+        uint8_t     *image;     /* Pointer into raw data buffer */
 
         HDassert(fl->offset == H5HL_ALIGN(fl->offset));
-        p = heap->dblk_image + fl->offset;
+        image = heap->dblk_image + fl->offset;
 
         if(fl->next)
-            H5F_ENCODE_LENGTH_LEN(p, fl->next->offset, heap->sizeof_size)
+            H5F_ENCODE_LENGTH_LEN(image, fl->next->offset, heap->sizeof_size)
         else
-            H5F_ENCODE_LENGTH_LEN(p, H5HL_FREE_NULL, heap->sizeof_size)
+            H5F_ENCODE_LENGTH_LEN(image, H5HL_FREE_NULL, heap->sizeof_size)
 
-        H5F_ENCODE_LENGTH_LEN(p, fl->size, heap->sizeof_size)
+        H5F_ENCODE_LENGTH_LEN(image, fl->size, heap->sizeof_size)
     } /* end for */
 
     FUNC_LEAVE_NOAPI_VOID
@@ -235,69 +255,88 @@ H5HL__fl_serialize(const H5HL_t *heap)
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5HL_prefix_load
+ * Function:    H5HL__cache_prefix_get_load_size()
  *
- * Purpose:	Loads a local heap prefix from disk.
+ * Purpose:	Return the size of the buffer the metadata cache should 
+ *		load from file and pass to the deserialize routine.
  *
- * Return:	Success:	Ptr to a local heap memory data structure.
- *		Failure:	NULL
+ *		The version 2 metadata cache callbacks included a test to 
+ *		ensure that the read did not pass the end of file, but this 
+ *		functionality has been moved to H5C_load_entry().  Thus 
+ *		all this function does is set *image_len equal to 
+ *		H5HL_SPEC_READ_SIZE, leaving it to the metadata cache to 
+ *		reduce the size of the read if appropriate.
  *
- * Programmer:	Robb Matzke
- *		matzke@llnl.gov
- *		Jul 17 1997
+ * Return:      Success:        SUCCEED
+ *              Failure:        FAIL
+ *
+ * Programmer:  John Mainzer
+ *              6/21/14
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+H5HL__cache_prefix_get_load_size(const void H5_ATTR_UNUSED *_udata, size_t *image_len)
+{
+    FUNC_ENTER_STATIC_NOERR
+
+    HDassert(image_len);
+
+    *image_len = H5HL_SPEC_READ_SIZE;
+
+    FUNC_LEAVE_NOAPI(SUCCEED)
+} /* end H5HL__cache_prefix_get_load_size() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:    H5HL__cache_prefix_deserialize
+ *
+ * Purpose:	Given a buffer containing the on disk image of the local 
+ *		heap prefix, deserialize it, load its contents into a newly allocated
+ *		instance of H5HL_prfx_t, and return a pointer to the new instance.
+ *
+ * Return:      Success:        Pointer to in core representation
+ *              Failure:        NULL
+ *
+ * Programmer:  John Mainzer
+ *              6/21/14
  *
  *-------------------------------------------------------------------------
  */
 static void *
-H5HL_prefix_load(H5F_t *f, hid_t dxpl_id, haddr_t addr, void *_udata)
+H5HL__cache_prefix_deserialize(const void *_image, size_t len, void *_udata,
+    hbool_t H5_ATTR_UNUSED *dirty)
 {
-    H5HL_t *heap = NULL;            /* Local heap */
-    H5HL_prfx_t *prfx = NULL;       /* Heap prefix deserialized */
+    H5HL_t               *heap = NULL;  /* Local heap */
+    H5HL_prfx_t          *prfx = NULL;  /* Heap prefix deserialized */
+    const uint8_t        *image = (const uint8_t *)_image;      /* Pointer into decoding buffer */
     H5HL_cache_prfx_ud_t *udata = (H5HL_cache_prfx_ud_t *)_udata;       /* User data for callback */
-    uint8_t		buf[H5HL_SPEC_READ_SIZE];   /* Buffer for decoding */
-    size_t	        spec_read_size; /* Size of buffer to speculatively read in */
-    const uint8_t	*p;         /* Pointer into decoding buffer */
-    haddr_t             eoa;        /* Relative end of file address */
-    hsize_t min;                    /* temp min value to avoid macro nesting */
-    H5HL_prfx_t *ret_value;         /* Return value */
+    void                 *ret_value;    /* Return value */
 
-    FUNC_ENTER_NOAPI_NOINIT
+    FUNC_ENTER_STATIC
 
-    /* check arguments */
-    HDassert(f);
-    HDassert(H5F_addr_defined(addr));
+    /* Check arguments */
+    HDassert(image);
+    HDassert(len > 0);
     HDassert(udata);
     HDassert(udata->sizeof_size > 0);
     HDassert(udata->sizeof_addr > 0);
     HDassert(udata->sizeof_prfx > 0);
-    HDassert(udata->sizeof_prfx <= sizeof(buf));
-
-    /* Make certain we don't speculatively read off the end of the file */
-    if(HADDR_UNDEF == (eoa = H5F_get_eoa(f, H5FD_MEM_LHEAP)))
-        HGOTO_ERROR(H5E_HEAP, H5E_CANTGET, NULL, "unable to determine file size")
-
-    /* Compute the size of the speculative local heap prefix buffer */
-    min = MIN(eoa - addr, H5HL_SPEC_READ_SIZE);
-    H5_CHECKED_ASSIGN(spec_read_size, size_t, min, hsize_t);
-    HDassert(spec_read_size >= udata->sizeof_prfx);
-
-    /* Attempt to speculatively read both local heap prefix and heap data */
-    if(H5F_block_read(f, H5FD_MEM_LHEAP, addr, spec_read_size, dxpl_id, buf) < 0)
-	HGOTO_ERROR(H5E_HEAP, H5E_READERROR, NULL, "unable to read local heap prefix")
-    p = buf;
+    HDassert(H5F_addr_defined(udata->prfx_addr));
+    HDassert(dirty);
 
     /* Check magic number */
-    if(HDmemcmp(p, H5HL_MAGIC, (size_t)H5_SIZEOF_MAGIC))
-	HGOTO_ERROR(H5E_HEAP, H5E_BADVALUE, NULL, "bad local heap signature")
-    p += H5_SIZEOF_MAGIC;
+    if(HDmemcmp(image, H5HL_MAGIC, (size_t)H5_SIZEOF_MAGIC)) 
+        HGOTO_ERROR(H5E_HEAP, H5E_BADVALUE, NULL, "bad local heap signature")
+    image += H5_SIZEOF_MAGIC;
 
     /* Version */
-    if(H5HL_VERSION != *p++)
-	HGOTO_ERROR(H5E_HEAP, H5E_BADVALUE, NULL, "wrong version number in local heap")
+    if(H5HL_VERSION != *image++) 
+        HGOTO_ERROR(H5E_HEAP, H5E_BADVALUE, NULL, "wrong version number in local heap")
 
     /* Reserved */
-    p += 3;
-
+    image += 3;
+    
     /* Allocate space in memory for the heap */
     if(NULL == (heap = H5HL_new(udata->sizeof_size, udata->sizeof_addr, udata->sizeof_prfx)))
         HGOTO_ERROR(H5E_HEAP, H5E_CANTALLOC, NULL, "can't allocate local heap structure")
@@ -311,16 +350,16 @@ H5HL_prefix_load(H5F_t *f, hid_t dxpl_id, haddr_t addr, void *_udata)
     heap->prfx_size = udata->sizeof_prfx;
 
     /* Heap data size */
-    H5F_DECODE_LENGTH_LEN(p, heap->dblk_size, udata->sizeof_size);
+    H5F_DECODE_LENGTH_LEN(image, heap->dblk_size, udata->sizeof_size);
 
     /* Free list head */
-    H5F_DECODE_LENGTH_LEN(p, heap->free_block, udata->sizeof_size);
+    H5F_DECODE_LENGTH_LEN(image, heap->free_block, udata->sizeof_size);
 
     if((heap->free_block != H5HL_FREE_NULL) && (heap->free_block >= heap->dblk_size))
         HGOTO_ERROR(H5E_HEAP, H5E_BADVALUE, NULL, "bad heap free list")
 
     /* Heap data address */
-    H5F_addr_decode_len(udata->sizeof_addr, &p, &(heap->dblk_addr));
+    H5F_addr_decode_len(udata->sizeof_addr, &image, &(heap->dblk_addr));
 
     /* Check if heap block exists */
     if(heap->dblk_size) {
@@ -329,35 +368,53 @@ H5HL_prefix_load(H5F_t *f, hid_t dxpl_id, haddr_t addr, void *_udata)
             /* Note that the heap should be a single object in the cache */
             heap->single_cache_obj = TRUE;
 
-            /* Allocate space for the heap data image */
-            if(NULL == (heap->dblk_image = H5FL_BLK_MALLOC(lheap_chunk, heap->dblk_size)))
-                HGOTO_ERROR(H5E_HEAP, H5E_CANTALLOC, NULL, "memory allocation failed")
+            /* Check if the current buffer from the speculative read 
+             * already has the heap data 
+             */
+            if(len >= (heap->prfx_size + heap->dblk_size)) {
+                /* Allocate space for the heap data image */
+                if(NULL == (heap->dblk_image = H5FL_BLK_MALLOC(lheap_chunk, heap->dblk_size)))
+                    HGOTO_ERROR(H5E_HEAP, H5E_CANTALLOC, NULL, "memory allocation failed")
 
-            /* Check if the current buffer from the speculative read already has the heap data */
-            if(spec_read_size >= (heap->prfx_size + heap->dblk_size)) {
-                /* Set p to the start of the data block.  This is necessary
+                /* Set image to the start of the data block.  This is necessary
                  * because there may be a gap between the used portion of the
                  * prefix and the data block due to alignment constraints. */
-                p = buf + heap->prfx_size;
+                image = ((const uint8_t *)_image) + heap->prfx_size;
 
                 /* Copy the heap data from the speculative read buffer */
-                HDmemcpy(heap->dblk_image, p, heap->dblk_size);
+                HDmemcpy(heap->dblk_image, image, heap->dblk_size);
+
+                /* Build free list */
+                if(H5HL__fl_deserialize(heap) < 0)
+                    HGOTO_ERROR(H5E_HEAP, H5E_CANTINIT, NULL, "can't initialize free list")
             } /* end if */
             else {
-                /* Read the local heap data block directly into buffer */
-                if(H5F_block_read(f, H5FD_MEM_LHEAP, heap->dblk_addr, heap->dblk_size, dxpl_id, heap->dblk_image) < 0)
-                    HGOTO_ERROR(H5E_HEAP, H5E_READERROR, NULL, "unable to read heap data")
-            } /* end else */
-
-            /* Build free list */
-            if(H5HL__fl_deserialize(heap) < 0)
-                HGOTO_ERROR(H5E_HEAP, H5E_CANTINIT, NULL, "can't initialize free list")
+		/* the supplied buffer is too small -- We have already made note
+                 * of the correct size, so simply return success.  H5C_load_entry()
+                 * will notice the size discrepency, and re-try the load.
+                 */
+
+                /* Make certain that this is the first try ... */
+                HDassert(!udata->made_attempt);
+
+                /* ... and mark the udata so that we know that we have used up
+                 * our first try.
+                 */
+                udata->made_attempt = TRUE;
+	    } /* end else */
         } /* end if */
-        else
-            /* Note that the heap should _NOT_ be a single object in the cache */
+        else {
+            /* Note that the heap should _NOT_ be a single 
+             * object in the cache 
+             */
             heap->single_cache_obj = FALSE;
+
+	} /* end else */
     } /* end if */
 
+    /* Set flag to indicate prefix from loaded from file */
+    udata->loaded = TRUE;
+
     /* Set return value */
     ret_value = prfx;
 
@@ -375,273 +432,257 @@ done:
     } /* end if */
 
     FUNC_LEAVE_NOAPI(ret_value)
-} /* end H5HL_prefix_load() */
+} /* end H5HL__cache_prefix_deserialize() */
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5HL_prefix_flush
+ * Function:    H5HL__cache_prefix_image_len
  *
- * Purpose:	Flushes a heap from memory to disk if it's dirty.  Optionally
- *		deletes the heap from memory.
+ * Purpose:	Return the on disk image size of a local heap prefix to the 
+ *		metadata cache via the image_len.
  *
- * Return:	Non-negative on success/Negative on failure
+ * Return:      Success:        SUCCEED
+ *              Failure:        FAIL
  *
- * Programmer:	Robb Matzke
- *		matzke@llnl.gov
- *		Jul 17 1997
+ * Programmer:  John Mainzer
+ *              6/21/14
  *
  *-------------------------------------------------------------------------
  */
 static herr_t
-H5HL_prefix_flush(H5F_t *f, hid_t dxpl_id, hbool_t destroy, haddr_t addr,
-    void *thing, unsigned H5_ATTR_UNUSED *flags_ptr)
+H5HL__cache_prefix_image_len(const void *_thing, size_t *image_len,
+    hbool_t H5_ATTR_UNUSED *compressed_ptr, size_t H5_ATTR_UNUSED *compressed_image_len_ptr)
 {
-    H5HL_prfx_t *prfx = (H5HL_prfx_t *)thing;   /* Local heap prefix to flush */
-    H5WB_t *wb = NULL;                  /* Wrapped buffer for heap data */
-    uint8_t heap_buf[H5HL_SPEC_READ_SIZE]; /* Buffer for heap */
-    herr_t ret_value = SUCCEED;         /* Return value */
+    const H5HL_prfx_t *prfx = (const H5HL_prfx_t *)_thing;  /* Pointer to local heap prefix to query */
 
-    FUNC_ENTER_NOAPI_NOINIT
+    FUNC_ENTER_STATIC_NOERR
 
-    /* check arguments */
-    HDassert(f);
-    HDassert(H5F_addr_defined(addr));
+    /* Check arguments */
     HDassert(prfx);
+    HDassert(prfx->cache_info.magic == H5C__H5C_CACHE_ENTRY_T_MAGIC);
+    HDassert(prfx->cache_info.type == H5AC_LHEAP_PRFX);
+    HDassert(image_len);
 
-    if(prfx->cache_info.is_dirty) {
-        H5HL_t *heap = prfx->heap; /* Pointer to the local heap */
-        uint8_t *buf;           /* Pointer to heap buffer */
-        size_t buf_size;        /* Size of buffer for encoding & writing heap info */
-        uint8_t *p;             /* Pointer into raw data buffer */
-
-        /* Wrap the local buffer for serialized heap info */
-        if(NULL == (wb = H5WB_wrap(heap_buf, sizeof(heap_buf))))
-            HGOTO_ERROR(H5E_HEAP, H5E_CANTINIT, FAIL, "can't wrap buffer")
-
-        /* Compute the size of the buffer to encode & write */
-        buf_size = heap->prfx_size;
-        if(heap->single_cache_obj)
-            buf_size += heap->dblk_size;
-
-        /* Get a pointer to a buffer that's large enough for serialized heap */
-        if(NULL == (buf = (uint8_t *)H5WB_actual(wb, buf_size)))
-            HGOTO_ERROR(H5E_HEAP, H5E_NOSPACE, FAIL, "can't get actual buffer")
-
-        /* Update the free block value from the free list */
-        heap->free_block = heap->freelist ? heap->freelist->offset : H5HL_FREE_NULL;
-
-        /* Serialize the heap prefix */
-        p = buf;
-        HDmemcpy(p, H5HL_MAGIC, (size_t)H5_SIZEOF_MAGIC);
-        p += H5_SIZEOF_MAGIC;
-        *p++ = H5HL_VERSION;
-        *p++ = 0;	/*reserved*/
-        *p++ = 0;	/*reserved*/
-        *p++ = 0;	/*reserved*/
-        H5F_ENCODE_LENGTH_LEN(p, heap->dblk_size, heap->sizeof_size);
-        H5F_ENCODE_LENGTH_LEN(p, heap->free_block, heap->sizeof_size);
-        H5F_addr_encode_len(heap->sizeof_addr, &p, heap->dblk_addr);
-
-        /* Check if the local heap is a single object in cache */
-        if(heap->single_cache_obj) {
-            if((size_t)(p - buf) < heap->prfx_size) {
-                size_t gap;         /* Size of gap between prefix and data block */
-
-                /* Set p to the start of the data block.  This is necessary because
-                 * there may be a gap between the used portion of the prefix and the
-                 * data block due to alignment constraints. */
-                gap = heap->prfx_size - (size_t)(p - buf);
-                HDmemset(p, 0, gap);
-                p += gap;
-            } /* end if */
-
-            /* Serialize the free list into the heap data's image */
-            H5HL__fl_serialize(heap);
-
-            /* Copy the heap data block into the cache image */
-            HDmemcpy(p, heap->dblk_image, heap->dblk_size);
-        } /* end if */
-
-        /* Write the prefix [and possibly the data block] to the file */
-        if(H5F_block_write(f, H5FD_MEM_LHEAP, addr, buf_size, dxpl_id, buf) < 0)
-            HGOTO_ERROR(H5E_HEAP, H5E_WRITEERROR, FAIL, "unable to write heap header and data to file")
+    /* Set the prefix's size */
+    *image_len = prfx->heap->prfx_size;
 
-	prfx->cache_info.is_dirty = FALSE;
-    } /* end if */
+    /* If the heap is stored as a single object, add in the 
+     * data block size also 
+     */
+    if(prfx->heap->single_cache_obj)
+        *image_len += prfx->heap->dblk_size;
 
-    /* Should we destroy the memory version? */
-    if(destroy)
-        if(H5HL_prefix_dest(f, prfx) < 0)
-	    HGOTO_ERROR(H5E_HEAP, H5E_CANTFREE, FAIL, "unable to destroy local heap prefix")
 
-done:
-    /* Release resources */
-    if(wb && H5WB_unwrap(wb) < 0)
-        HDONE_ERROR(H5E_HEAP, H5E_CLOSEERROR, FAIL, "can't close wrapped buffer")
+    FUNC_LEAVE_NOAPI(SUCCEED)
+} /* end H5HL__cache_prefix_image_len() */
 
-    FUNC_LEAVE_NOAPI(ret_value)
-} /* end H5HL_prefix_flush() */
+/****************************************/
+/* no H5HL_cache_prefix_pre_serialize() */
+/****************************************/
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5HL_prefix_dest
+ * Function:    H5HL__cache_prefix_serialize
  *
- * Purpose:	Destroys a heap prefix in memory.
+ * Purpose:	Given a pointer to an instance of H5HL_prfx_t and an 
+ *		appropriately sized buffer, serialize the contents of the 
+ *		instance for writing to disk, and copy the serialized data 
+ *		into the buffer.
  *
- * Return:	Non-negative on success/Negative on failure
+ * Return:      Success:        SUCCEED
+ *              Failure:        FAIL
  *
- * Programmer:	Quincey Koziol
- *		koziol@ncsa.uiuc.edu
- *		Jan 15 2003
+ * Programmer:  John Mainzer
+ *              7/21/14
  *
  *-------------------------------------------------------------------------
  */
 static herr_t
-H5HL_prefix_dest(H5F_t *f, void *thing)
+H5HL__cache_prefix_serialize(const H5F_t *f, void *_image, size_t len,
+    void *_thing)
 {
-    H5HL_prfx_t *prfx = (H5HL_prfx_t *)thing;   /* Local heap prefix to destroy */
-    herr_t ret_value = SUCCEED;         /* Return value */
+    H5HL_prfx_t *prfx = (H5HL_prfx_t *)_thing;  /* Pointer to local heap prefix to query */
+    H5HL_t      *heap;          /* Pointer to the local heap */
+    uint8_t     *image = (uint8_t *)_image;     /* Pointer into image buffer */
+    size_t       buf_size;      /* expected size of the image buffer */
 
-    FUNC_ENTER_NOAPI_NOINIT
+    FUNC_ENTER_STATIC_NOERR
 
-    /* check arguments */
+    /* Check arguments */
+    HDassert(f);
+    HDassert(image);
     HDassert(prfx);
-    HDassert(prfx->heap);
+    HDassert(prfx->cache_info.magic == H5C__H5C_CACHE_ENTRY_T_MAGIC);
+    HDassert(prfx->cache_info.type == H5AC_LHEAP_PRFX);
     HDassert(H5F_addr_eq(prfx->cache_info.addr, prfx->heap->prfx_addr));
+    HDassert(prfx->heap);
 
-    /* Verify that entry is clean */
-    HDassert(prfx->cache_info.is_dirty == FALSE);
-
-    /* If we're going to free the space on disk, the address must be valid */
-    HDassert(!prfx->cache_info.free_file_space_on_destroy || H5F_addr_defined(prfx->cache_info.addr));
+    /* Get the pointer to the heap */
+    heap = prfx->heap;
+    HDassert(heap);
 
-    /* Check for freeing file space for local heap prefix */
-    if(prfx->cache_info.free_file_space_on_destroy) {
-        hsize_t free_size;       /* Size of region to free in file */
+    /* Compute the buffer size */
+    buf_size = heap->prfx_size;
+    if(heap->single_cache_obj)
+        buf_size += heap->dblk_size;
+    HDassert(len == buf_size);
+
+    /* Update the free block value from the free list */
+    heap->free_block = heap->freelist ? heap->freelist->offset : H5HL_FREE_NULL;
+
+    /* Serialize the heap prefix */
+    HDmemcpy(image, H5HL_MAGIC, (size_t)H5_SIZEOF_MAGIC);
+    image += H5_SIZEOF_MAGIC;
+    *image++ = H5HL_VERSION;
+    *image++ = 0;       /*reserved*/
+    *image++ = 0;       /*reserved*/
+    *image++ = 0;       /*reserved*/
+    H5F_ENCODE_LENGTH_LEN(image, heap->dblk_size, heap->sizeof_size);
+    H5F_ENCODE_LENGTH_LEN(image, heap->free_block, heap->sizeof_size);
+    H5F_addr_encode_len(heap->sizeof_addr, &image, heap->dblk_addr);
+
+    /* Check if the local heap is a single object in cache */
+    if(heap->single_cache_obj) {
+        if((size_t)(image - (uint8_t *)_image) < heap->prfx_size) {
+            size_t gap;         /* Size of gap between prefix and data block */
+
+            /* Set image to the start of the data block.  This is necessary 
+             * because there may be a gap between the used portion of 
+             * the prefix and the data block due to alignment constraints. 
+             */
+            gap = heap->prfx_size - (size_t)(image - (uint8_t *)_image);
+            HDmemset(image, 0, gap);
+            image += gap;
+        } /* end if */
 
-        /* Compute size to free for later */
-        free_size = prfx->heap->prfx_size;
-        if(prfx->heap->single_cache_obj)
-            free_size += prfx->heap->dblk_size;
+        /* Serialize the free list into the heap data's image */
+        H5HL__fl_serialize(heap);
 
-        /* Free the local heap prefix [and possible the data block] on disk */
-        /* (XXX: Nasty usage of internal DXPL value! -QAK) */
-        if(H5MF_xfree(f, H5FD_MEM_LHEAP, H5AC_dxpl_id, prfx->cache_info.addr, free_size) < 0)
-            HGOTO_ERROR(H5E_HEAP, H5E_CANTFREE, FAIL, "unable to free local heap prefix")
+        /* Copy the heap data block into the cache image */
+        HDmemcpy(image, heap->dblk_image, heap->dblk_size);
     } /* end if */
 
-    /* Destroy local heap prefix */
-    if(H5HL_prfx_dest(prfx) < 0)
-        HGOTO_ERROR(H5E_HEAP, H5E_CANTRELEASE, FAIL, "can't destroy local heap prefix")
+    FUNC_LEAVE_NOAPI(SUCCEED)
+} /* end H5HL__cache_prefix_serialize() */
 
-done:
-    FUNC_LEAVE_NOAPI(ret_value)
-} /* end H5HL_prefix_dest() */
+/******************************************/
+/* no H5HL_cache_prefix_notify() function */
+/******************************************/
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5HL_prefix_clear
+ * Function:    H5HL__cache_prefix_free_icr
  *
- * Purpose:	Mark a local heap prefix in memory as non-dirty.
+ * Purpose:	Free the supplied in core representation of a local heap 
+ *		prefix.
  *
- * Return:	Non-negative on success/Negative on failure
+ *		Note that this function handles the partially initialize prefix 
+ *		from a failed speculative load attempt.  See comments below for 
+ *		details.
  *
- * Programmer:	Quincey Koziol
- *		koziol@ncsa.uiuc.edu
- *		Mar 20 2003
+ * Note:	The metadata cache sets the object's cache_info.magic to
+ *		H5C__H5C_CACHE_ENTRY_T_BAD_MAGIC before calling a free_icr
+ *		callback (checked in assert).
+ *
+ * Return:      Success:        SUCCEED
+ *              Failure:        FAIL
+ *
+ * Programmer:  John Mainzer
+ *              6/21/14
  *
  *-------------------------------------------------------------------------
  */
 static herr_t
-H5HL_prefix_clear(H5F_t H5_ATTR_UNUSED *f, void *thing, hbool_t destroy)
+H5HL__cache_prefix_free_icr(void *_thing)
 {
-    H5HL_prfx_t *prfx = (H5HL_prfx_t *)thing;   /* The local heap prefix to operate on */
-    herr_t ret_value = SUCCEED;         /* Return value */
+    H5HL_prfx_t *prfx = (H5HL_prfx_t *)_thing;  /* Pointer to local heap prefix to query */
+    herr_t       ret_value = SUCCEED;    /* Return value */
 
-    FUNC_ENTER_NOAPI_NOINIT
+    FUNC_ENTER_STATIC
 
-    /* check arguments */
+    /* Check arguments */
     HDassert(prfx);
+    HDassert(prfx->cache_info.magic == H5C__H5C_CACHE_ENTRY_T_BAD_MAGIC);
+    HDassert(prfx->cache_info.type == H5AC_LHEAP_PRFX);
+    HDassert(H5F_addr_eq(prfx->cache_info.addr, prfx->heap->prfx_addr));
 
-    /* Mark heap prefix as clean */
-    prfx->cache_info.is_dirty = FALSE;
-
-    if(destroy)
-        if(H5HL_prefix_dest(f, prfx) < 0)
-	    HGOTO_ERROR(H5E_HEAP, H5E_CANTFREE, FAIL, "unable to destroy local heap prefix")
+    /* Destroy local heap prefix */
+    if(H5HL_prfx_dest(prfx) < 0)
+        HGOTO_ERROR(H5E_HEAP, H5E_CANTRELEASE, FAIL, "can't destroy local heap prefix")
 
 done:
     FUNC_LEAVE_NOAPI(ret_value)
-} /* end H5HL_prefix_clear() */
+} /* end H5HL__cache_prefix_free_icr() */
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5HL_prefix_size
+ * Function:    H5HL__cache_datablock_get_load_size()
  *
- * Purpose:	Compute the size in bytes of the heap prefix on disk,
- *              and return it in *len_ptr.  On failure, the value of *len_ptr
- *              is undefined.
+ * Purpose:	Tell the metadata cache how large a buffer to read from 
+ *		file when loading a datablock.  In this case, we simply lookup
+ *		the correct value in the user data, and return it in *image_len.
  *
- * Return:	Non-negative on success/Negative on failure
+ * Return:      Success:        SUCCEED
+ *              Failure:        FAIL
  *
- * Programmer:	John Mainzer
- *		5/13/04
+ * Programmer:  John Mainzer
+ *              6/21/14
  *
  *-------------------------------------------------------------------------
  */
 static herr_t
-H5HL_prefix_size(const H5F_t H5_ATTR_UNUSED *f, const void *thing, size_t *size_ptr)
+H5HL__cache_datablock_get_load_size(const void *_udata, size_t *image_len)
 {
-    const H5HL_prfx_t *prfx = (const H5HL_prfx_t *)thing;   /* Pointer to local heap prefix to query */
-
-    FUNC_ENTER_NOAPI_NOINIT_NOERR
+    const H5HL_cache_dblk_ud_t *udata = (const H5HL_cache_dblk_ud_t *)_udata; /* User data for callback */
 
-    /* check arguments */
-    HDassert(prfx);
-    HDassert(prfx->heap);
-    HDassert(size_ptr);
+    FUNC_ENTER_STATIC_NOERR
 
-    /* Calculate size of prefix in cache */
-    *size_ptr = prfx->heap->prfx_size;
+    /* Check arguments */
+    HDassert(udata);
+    HDassert(udata->heap);
+    HDassert(udata->heap->dblk_size > 0);
+    HDassert(image_len);
 
-    /* If the heap is stored as a single object, add in the data block size also */
-    if(prfx->heap->single_cache_obj)
-        *size_ptr += prfx->heap->dblk_size;
+    *image_len = udata->heap->dblk_size;
 
     FUNC_LEAVE_NOAPI(SUCCEED)
-} /* H5HL_prefix_size() */
+} /* end H5HL__cache_datablock_get_load_size() */
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5HL_datablock_load
+ * Function:    H5HL__cache_datablock_deserialize
  *
- * Purpose:	Loads a local heap data block from disk.
+ * Purpose:	Given a buffer containing the on disk image of a local 
+ *		heap data block, deserialize it, load its contents into a newly allocated
+ *		instance of H5HL_dblk_t, and return a pointer to the new instance.
  *
- * Return:	Success:	Ptr to a local heap data block memory data structure.
- *		Failure:	NULL
+ * Return:      Success:        Pointer to in core representation
+ *              Failure:        NULL
  *
- * Programmer:	Quincey Koziol
- *		koziol@hdfgroup.org
- *		Jan  5 2010
+ * Programmer:  John Mainzer
+ *              6/21/14
  *
  *-------------------------------------------------------------------------
  */
 static void *
-H5HL_datablock_load(H5F_t *f, hid_t dxpl_id, haddr_t addr, void *_udata)
+H5HL__cache_datablock_deserialize(const void *image, size_t len, void *_udata,
+    hbool_t H5_ATTR_UNUSED *dirty)
 {
-    H5HL_dblk_t *dblk = NULL;       /* Local heap data block deserialized */
-    H5HL_cache_dblk_ud_t *udata = (H5HL_cache_dblk_ud_t *)_udata;       /* User data for callback */
-    H5HL_dblk_t *ret_value;         /* Return value */
+    H5HL_dblk_t          *dblk = NULL;  /* Local heap data block deserialized */
+    H5HL_cache_dblk_ud_t *udata = (H5HL_cache_dblk_ud_t *)_udata; /* User data for callback */
+    void *                ret_value;    /* Return value */
 
-    FUNC_ENTER_NOAPI_NOINIT
+    FUNC_ENTER_STATIC
 
     /* Check arguments */
-    HDassert(f);
-    HDassert(H5F_addr_defined(addr));
+    HDassert(image);
+    HDassert(len > 0);
     HDassert(udata);
     HDassert(udata->heap);
+    HDassert(udata->heap->dblk_size == len);
     HDassert(!udata->heap->single_cache_obj);
     HDassert(NULL == udata->heap->dblk);
+    HDassert(dirty);
 
     /* Allocate space in memory for the heap data block */
     if(NULL == (dblk = H5HL_dblk_new(udata->heap)))
@@ -653,9 +694,8 @@ H5HL_datablock_load(H5F_t *f, hid_t dxpl_id, haddr_t addr, void *_udata)
         if(NULL == (udata->heap->dblk_image = H5FL_BLK_MALLOC(lheap_chunk, udata->heap->dblk_size)))
             HGOTO_ERROR(H5E_HEAP, H5E_CANTALLOC, NULL, "can't allocate data block image buffer")
 
-        /* Read local heap data block */
-        if(H5F_block_read(f, H5FD_MEM_LHEAP, udata->heap->dblk_addr, udata->heap->dblk_size, dxpl_id, udata->heap->dblk_image) < 0)
-            HGOTO_ERROR(H5E_HEAP, H5E_READERROR, NULL, "unable to read local heap data block")
+        /* copy the datablock from the read buffer */
+        HDmemcpy(udata->heap->dblk_image, image, len);
 
         /* Build free list */
         if(H5HL__fl_deserialize(udata->heap) < 0)
@@ -675,180 +715,134 @@ done:
             HDONE_ERROR(H5E_HEAP, H5E_CANTRELEASE, NULL, "unable to destroy local heap data block")
 
     FUNC_LEAVE_NOAPI(ret_value)
-} /* end H5HL_datablock_load() */
+} /* end H5HL__cache_datablock_deserialize() */
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5HL_datablock_flush
+ * Function:    H5HL__cache_datablock_image_len
  *
- * Purpose:	Flushes a heap's data block from memory to disk if it's dirty.
- *              Optionally deletes the heap data block from memory.
+ * Purpose:	Return the size of the on disk image of the datablock.
  *
- * Return:	Non-negative on success/Negative on failure
+ * Return:      Success:        SUCCEED
+ *              Failure:        FAIL
  *
- * Programmer:	Robb Matzke
- *		matzke@llnl.gov
- *		Jul 17 1997
+ * Programmer:  John Mainzer
+ *              6/21/14
  *
  *-------------------------------------------------------------------------
  */
 static herr_t
-H5HL_datablock_flush(H5F_t *f, hid_t dxpl_id, hbool_t destroy, haddr_t addr,
-    void *_thing, unsigned H5_ATTR_UNUSED * flags_ptr)
+H5HL__cache_datablock_image_len(const void *_thing, size_t *image_len,
+    hbool_t H5_ATTR_UNUSED *compressed_ptr, size_t H5_ATTR_UNUSED *compressed_image_len_ptr)
 {
-    H5HL_dblk_t *dblk = (H5HL_dblk_t *)_thing; /* Pointer to the local heap data block */
-    herr_t ret_value = SUCCEED;         /* Return value */
+    const H5HL_dblk_t *dblk = (const H5HL_dblk_t *)_thing;    /* Pointer to the local heap data block */
 
-    FUNC_ENTER_NOAPI_NOINIT
+    FUNC_ENTER_STATIC_NOERR
 
-    /* check arguments */
-    HDassert(f);
-    HDassert(H5F_addr_defined(addr));
+    /* Check arguments */
     HDassert(dblk);
+    HDassert(dblk->cache_info.magic == H5C__H5C_CACHE_ENTRY_T_MAGIC);
+    HDassert(dblk->cache_info.type == H5AC_LHEAP_DBLK);
     HDassert(dblk->heap);
-    HDassert(!dblk->heap->single_cache_obj);
-
-    if(dblk->cache_info.is_dirty) {
-        H5HL_t *heap = dblk->heap;      /* Pointer to the local heap */
-
-        /* Update the free block value from the free list */
-        heap->free_block = heap->freelist ? heap->freelist->offset : H5HL_FREE_NULL;
+    HDassert(dblk->heap->dblk_size > 0);
+    HDassert(image_len);
 
-        /* Serialize the free list into the heap data's image */
-        H5HL__fl_serialize(heap);
-
-        /* Write the data block to the file */
-        if(H5F_block_write(f, H5FD_MEM_LHEAP, heap->dblk_addr, heap->dblk_size, dxpl_id, heap->dblk_image) < 0)
-            HGOTO_ERROR(H5E_HEAP, H5E_WRITEERROR, FAIL, "unable to write heap data block to file")
-
-	dblk->cache_info.is_dirty = FALSE;
-    } /* end if */
+    *image_len = dblk->heap->dblk_size;
 
-    /* Should we destroy the memory version? */
-    if(destroy)
-        if(H5HL_datablock_dest(f, dblk) < 0)
-	    HGOTO_ERROR(H5E_HEAP, H5E_CANTFREE, FAIL, "unable to destroy local heap data block")
+    FUNC_LEAVE_NOAPI(SUCCEED)
+} /* end H5HL__cache_datablock_image_len() */
 
-done:
-    FUNC_LEAVE_NOAPI(ret_value)
-} /* end H5HL_datablock_flush() */
+/*******************************************/
+/* no H5HL_cache_datablock_pre_serialize() */
+/*******************************************/
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5HL_datablock_dest
+ * Function:    H5HL__cache_datablock_serialize
  *
- * Purpose:	Destroys a local heap data block in memory.
+ * Purpose:	Serialize the supplied datablock, and copy the serialized
+ *		image into the supplied image buffer.
  *
- * Return:	Non-negative on success/Negative on failure
+ * Return:      Success:        SUCCEED
+ *              Failure:        FAIL
  *
- * Programmer:	Quincey Koziol
- *		koziol@ncsa.uiuc.edu
- *		Jan 15 2003
+ * Programmer:  John Mainzer
+ *              6/21/14
  *
  *-------------------------------------------------------------------------
  */
 static herr_t
-H5HL_datablock_dest(H5F_t *f, void *_thing)
+H5HL__cache_datablock_serialize(const H5F_t *f, void *image, size_t len,
+    void *_thing)
 {
-    H5HL_dblk_t *dblk = (H5HL_dblk_t *)_thing; /* Pointer to the local heap data block */
-    herr_t ret_value = SUCCEED;         /* Return value */
+    H5HL_t      *heap;          /* Pointer to the local heap */
+    H5HL_dblk_t *dblk = (H5HL_dblk_t *)_thing;  /* Pointer to the local heap data block */
 
-    FUNC_ENTER_NOAPI_NOINIT
+    FUNC_ENTER_STATIC_NOERR
 
     /* Check arguments */
+    HDassert(f);
+    HDassert(image);
     HDassert(dblk);
+    HDassert(dblk->cache_info.magic == H5C__H5C_CACHE_ENTRY_T_MAGIC);
+    HDassert(dblk->cache_info.type == H5AC_LHEAP_DBLK);
     HDassert(dblk->heap);
-    HDassert(!dblk->heap->single_cache_obj);
-    HDassert(H5F_addr_eq(dblk->cache_info.addr, dblk->heap->dblk_addr));
+    heap = dblk->heap;
+    HDassert(heap->dblk_size == len);
+    HDassert(!heap->single_cache_obj);
 
-    /* Verify that entry is clean */
-    HDassert(dblk->cache_info.is_dirty == FALSE);
+    /* Update the free block value from the free list */
+    heap->free_block = heap->freelist ? heap->freelist->offset : H5HL_FREE_NULL;
 
-    /* If we're going to free the space on disk, the address must be valid */
-    HDassert(!dblk->cache_info.free_file_space_on_destroy || H5F_addr_defined(dblk->cache_info.addr));
+    /* Serialize the free list into the heap data's image */
+    H5HL__fl_serialize(heap);
 
-    /* Check for freeing file space for local heap data block */
-    if(dblk->cache_info.free_file_space_on_destroy) {
-        /* Free the local heap data block on disk */
-        /* (XXX: Nasty usage of internal DXPL value! -QAK) */
-        if(H5MF_xfree(f, H5FD_MEM_LHEAP, H5AC_dxpl_id, dblk->cache_info.addr, (hsize_t)dblk->heap->dblk_size) < 0)
-            HGOTO_ERROR(H5E_HEAP, H5E_CANTFREE, FAIL, "unable to free local heap data block")
-    } /* end if */
+    /* Copy the heap's data block into the cache's image */
+    HDmemcpy(image, heap->dblk_image, heap->dblk_size);
 
-    /* Destroy local heap data block */
-    if(H5HL_dblk_dest(dblk) < 0)
-        HGOTO_ERROR(H5E_HEAP, H5E_CANTRELEASE, FAIL, "can't destroy local heap data block")
+    FUNC_LEAVE_NOAPI(SUCCEED)
+} /* end H5HL__cache_datablock_serialize() */
 
-done:
-    FUNC_LEAVE_NOAPI(ret_value)
-} /* end H5HL_datablock_dest() */
+/*********************************************/
+/* no H5HL_cache_datablock_notify() function */
+/*********************************************/
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5HL_datablock_clear
+ * Function:    H5HL__cache_datablock_free_icr
  *
- * Purpose:	Mark a local heap data block in memory as non-dirty.
+ * Purpose:	Free the in memory representation of the supplied local heap data block.
  *
- * Return:	Non-negative on success/Negative on failure
+ * Note:	The metadata cache sets the object's cache_info.magic to
+ *		H5C__H5C_CACHE_ENTRY_T_BAD_MAGIC before calling a free_icr
+ *		callback (checked in assert).
  *
- * Programmer:	Quincey Koziol
- *		koziol@ncsa.uiuc.edu
- *		Mar 20 2003
+ * Return:      Success:        SUCCEED
+ *              Failure:        FAIL
+ *
+ * Programmer:  John Mainzer
+ *              6/21/14
  *
  *-------------------------------------------------------------------------
  */
 static herr_t
-H5HL_datablock_clear(H5F_t *f, void *_thing, hbool_t destroy)
+H5HL__cache_datablock_free_icr(void *_thing)
 {
     H5HL_dblk_t *dblk = (H5HL_dblk_t *)_thing; /* Pointer to the local heap data block */
-    herr_t ret_value = SUCCEED;         /* Return value */
+    herr_t       ret_value = SUCCEED;    /* Return value */
 
-    FUNC_ENTER_NOAPI_NOINIT
+    FUNC_ENTER_STATIC
 
     /* Check arguments */
     HDassert(dblk);
+    HDassert(dblk->cache_info.magic == H5C__H5C_CACHE_ENTRY_T_BAD_MAGIC);
+    HDassert(dblk->cache_info.type == H5AC_LHEAP_DBLK);
 
-    /* Mark local heap data block as clean */
-    dblk->cache_info.is_dirty = FALSE;
-
-    if(destroy)
-        if(H5HL_datablock_dest(f, dblk) < 0)
-	    HGOTO_ERROR(H5E_HEAP, H5E_CANTFREE, FAIL, "unable to destroy local heap data block")
+    /* Destroy the data block */
+    if(H5HL_dblk_dest(dblk) < 0)
+        HGOTO_ERROR(H5E_HEAP, H5E_CANTFREE, FAIL, "unable to destroy local heap data block")
 
 done:
     FUNC_LEAVE_NOAPI(ret_value)
-} /* end H5HL_datablock_clear() */
-
-
-/*-------------------------------------------------------------------------
- * Function:	H5HL_datablock_size
- *
- * Purpose:	Compute the size in bytes of the local heap data block on disk,
- *              and return it in *len_ptr.  On failure, the value of *len_ptr
- *              is undefined.
- *
- * Return:	Non-negative on success/Negative on failure
- *
- * Programmer:	John Mainzer
- *		5/13/04
- *
- *-------------------------------------------------------------------------
- */
-static herr_t
-H5HL_datablock_size(const H5F_t H5_ATTR_UNUSED *f, const void *_thing, size_t *size_ptr)
-{
-    const H5HL_dblk_t *dblk = (const H5HL_dblk_t *)_thing; /* Pointer to the local heap data block */
-
-    FUNC_ENTER_NOAPI_NOINIT_NOERR
-
-    /* check arguments */
-    HDassert(dblk);
-    HDassert(dblk->heap);
-    HDassert(size_ptr);
-
-    /* Set size of data block in cache */
-    *size_ptr = dblk->heap->dblk_size;
-
-    FUNC_LEAVE_NOAPI(SUCCEED)
-} /* H5HL_datablock_size() */
+} /* end H5HL__cache_datablock_free_icr() */
 
diff --git a/src/H5HLdbg.c b/src/H5HLdbg.c
index 4ac22b8..edddd65 100644
--- a/src/H5HLdbg.c
+++ b/src/H5HLdbg.c
@@ -69,7 +69,7 @@ H5HL_debug(H5F_t *f, hid_t dxpl_id, haddr_t addr, FILE * stream, int indent, int
     HDassert(indent >= 0);
     HDassert(fwidth >= 0);
 
-    if(NULL == (h = (H5HL_t *)H5HL_protect(f, dxpl_id, addr, H5AC_READ)))
+    if(NULL == (h = (H5HL_t *)H5HL_protect(f, dxpl_id, addr, H5AC__READ_ONLY_FLAG)))
         HGOTO_ERROR(H5E_HEAP, H5E_CANTLOAD, FAIL, "unable to load heap")
 
     HDfprintf(stream, "%*sLocal Heap...\n", indent, "");
diff --git a/src/H5HLpkg.h b/src/H5HLpkg.h
index 880cc05..75c9959 100644
--- a/src/H5HLpkg.h
+++ b/src/H5HLpkg.h
@@ -122,12 +122,16 @@ struct H5HL_prfx_t {
 /* Callback information for loading local heap prefix from disk */
 typedef struct H5HL_cache_prfx_ud_t {
     /* Downwards */
+    hbool_t made_attempt;               /* Whether the deserialize routine */
+                                        /* was already attempted */
     size_t sizeof_size;                 /* Size of file sizes */
     size_t sizeof_addr;                 /* Size of file addresses */
     haddr_t prfx_addr;                  /* Address of prefix */
     size_t sizeof_prfx;                 /* Size of heap prefix */
 
     /* Upwards */
+    hbool_t loaded;                     /* Whether prefix was loaded */
+                                        /* from file */
 } H5HL_cache_prfx_ud_t;
 
 /* Callback information for loading local heap data block from disk */
diff --git a/src/H5HLprivate.h b/src/H5HLprivate.h
index 0b044b6..3035689 100644
--- a/src/H5HLprivate.h
+++ b/src/H5HLprivate.h
@@ -61,7 +61,7 @@ typedef struct H5HL_t H5HL_t;
  * Library prototypes...
  */
 H5_DLL herr_t H5HL_create(H5F_t *f, hid_t dxpl_id, size_t size_hint, haddr_t *addr/*out*/);
-H5_DLL H5HL_t *H5HL_protect(H5F_t *f, hid_t dxpl_id, haddr_t addr, H5AC_protect_t rw);
+H5_DLL H5HL_t *H5HL_protect(H5F_t *f, hid_t dxpl_id, haddr_t addr, unsigned flags);
 H5_DLL void *H5HL_offset_into(const H5HL_t *heap, size_t offset);
 H5_DLL herr_t H5HL_remove(H5F_t *f, hid_t dxpl_id, H5HL_t *heap, size_t offset,
     size_t size);
diff --git a/src/H5O.c b/src/H5O.c
index 22086fa..d0ace29 100644
--- a/src/H5O.c
+++ b/src/H5O.c
@@ -1652,7 +1652,7 @@ done:
  *-------------------------------------------------------------------------
  */
 H5O_t *
-H5O_protect(const H5O_loc_t *loc, hid_t dxpl_id, H5AC_protect_t prot)
+H5O_protect(const H5O_loc_t *loc, hid_t dxpl_id, unsigned prot_flags)
 {
     H5O_t *oh = NULL;           /* Object header protected */
     H5O_cache_ud_t udata;       /* User data for protecting object header */
@@ -1666,13 +1666,16 @@ H5O_protect(const H5O_loc_t *loc, hid_t dxpl_id, H5AC_protect_t prot)
     HDassert(loc);
     HDassert(loc->file);
 
+    /* prot_flags may only contain the H5AC__READ_ONLY_FLAG */
+    HDassert((prot_flags & (unsigned)(~H5AC__READ_ONLY_FLAG)) == 0);
+
     /* Check for valid address */
     if(!H5F_addr_defined(loc->addr))
         HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, NULL, "address undefined")
 
     /* Check for write access on the file */
     file_intent = H5F_INTENT(loc->file);
-    if((prot == H5AC_WRITE) && (0 == (file_intent & H5F_ACC_RDWR)))
+    if((0 == (prot_flags & H5AC__READ_ONLY_FLAG)) && (0 == (file_intent & H5F_ACC_RDWR)))
 	HGOTO_ERROR(H5E_OHDR, H5E_BADVALUE, NULL, "no write intent on file")
 
     /* Construct the user data for protect callback */
@@ -1688,7 +1691,7 @@ H5O_protect(const H5O_loc_t *loc, hid_t dxpl_id, H5AC_protect_t prot)
     udata.common.addr = loc->addr;
 
     /* Lock the object header into the cache */
-    if(NULL == (oh = (H5O_t *)H5AC_protect(loc->file, dxpl_id, H5AC_OHDR, loc->addr, &udata, prot)))
+    if(NULL == (oh = (H5O_t *)H5AC_protect(loc->file, dxpl_id, H5AC_OHDR, loc->addr, &udata, prot_flags)))
 	HGOTO_ERROR(H5E_OHDR, H5E_CANTPROTECT, NULL, "unable to load object header")
 
     /* Check if there are any continuation messages to process */
@@ -1725,7 +1728,7 @@ H5O_protect(const H5O_loc_t *loc, hid_t dxpl_id, H5AC_protect_t prot)
             /* (which adds to the object header) */
             chk_udata.common.addr = cont_msg_info.msgs[curr_msg].addr;
             chk_udata.size = cont_msg_info.msgs[curr_msg].size;
-            if(NULL == (chk_proxy = (H5O_chunk_proxy_t *)H5AC_protect(loc->file, dxpl_id, H5AC_OHDR_CHK, cont_msg_info.msgs[curr_msg].addr, &chk_udata, prot)))
+            if(NULL == (chk_proxy = (H5O_chunk_proxy_t *)H5AC_protect(loc->file, dxpl_id, H5AC_OHDR_CHK, cont_msg_info.msgs[curr_msg].addr, &chk_udata, prot_flags)))
                 HGOTO_ERROR(H5E_OHDR, H5E_CANTPROTECT, NULL, "unable to load object header chunk")
 
             /* Sanity check */
@@ -1769,7 +1772,7 @@ H5O_protect(const H5O_loc_t *loc, hid_t dxpl_id, H5AC_protect_t prot)
             /* (object header will have been marked dirty during protect, if we
              *  have write access -QAK)
              */
-            if(prot != H5AC_WRITE)
+            if((prot_flags & H5AC__READ_ONLY_FLAG) != 0)
                 oh->prefix_modified = TRUE;
 #ifndef NDEBUG
             else {
@@ -1787,7 +1790,7 @@ H5O_protect(const H5O_loc_t *loc, hid_t dxpl_id, H5AC_protect_t prot)
         } /* end if */
 
         /* Check for any messages that were modified while being read in */
-        if(udata.common.mesgs_modified && prot != H5AC_WRITE)
+        if(udata.common.mesgs_modified && (0 == (prot_flags & H5AC__READ_ONLY_FLAG)))
             oh->mesgs_modified = TRUE;
 
         /* Reset the field that contained chunk 0's size during speculative load */
@@ -1797,7 +1800,7 @@ H5O_protect(const H5O_loc_t *loc, hid_t dxpl_id, H5AC_protect_t prot)
     /* Take care of loose ends for modifications made while bringing in the
      *      object header & chunks.
      */
-    if(prot == H5AC_WRITE) {
+    if(0 == (prot_flags & H5AC__READ_ONLY_FLAG)) {
         /* Check for the object header prefix being modified somehow */
         /* (usually through updating the # of object header messages) */
         if(oh->prefix_modified) {
@@ -1883,7 +1886,7 @@ H5O_pin(const H5O_loc_t *loc, hid_t dxpl_id)
     HDassert(loc);
 
     /* Get header */
-    if(NULL == (oh = H5O_protect(loc, dxpl_id, H5AC_WRITE)))
+    if(NULL == (oh = H5O_protect(loc, dxpl_id, H5AC__NO_FLAGS_SET)))
 	HGOTO_ERROR(H5E_OHDR, H5E_CANTPROTECT, NULL, "unable to protect object header")
 
     /* Increment the reference count on the object header */
@@ -2096,7 +2099,7 @@ H5O_touch(const H5O_loc_t *loc, hbool_t force, hid_t dxpl_id)
     HDassert(loc);
 
     /* Get the object header */
-    if(NULL == (oh = H5O_protect(loc, dxpl_id, H5AC_WRITE)))
+    if(NULL == (oh = H5O_protect(loc, dxpl_id, H5AC__NO_FLAGS_SET)))
 	HGOTO_ERROR(H5E_OHDR, H5E_CANTPROTECT, FAIL, "unable to load object header")
 
     /* Create/Update the modification time message */
@@ -2212,7 +2215,7 @@ H5O_delete(H5F_t *f, hid_t dxpl_id, haddr_t addr)
     loc.holding_file = FALSE;
 
     /* Get the object header information */
-    if(NULL == (oh = H5O_protect(&loc, dxpl_id, H5AC_WRITE)))
+    if(NULL == (oh = H5O_protect(&loc, dxpl_id, H5AC__NO_FLAGS_SET)))
 	HGOTO_ERROR(H5E_OHDR, H5E_CANTPROTECT, FAIL, "unable to load object header")
 
     /* Delete object */
@@ -2296,7 +2299,7 @@ H5O_obj_type(const H5O_loc_t *loc, H5O_type_t *obj_type, hid_t dxpl_id)
     FUNC_ENTER_NOAPI_TAG(dxpl_id, loc->addr, FAIL)
 
     /* Load the object header */
-    if(NULL == (oh = H5O_protect(loc, dxpl_id, H5AC_READ)))
+    if(NULL == (oh = H5O_protect(loc, dxpl_id, H5AC__READ_ONLY_FLAG)))
 	HGOTO_ERROR(H5E_OHDR, H5E_CANTPROTECT, FAIL, "unable to load object header")
 
     /* Retrieve the type of the object */
@@ -2374,7 +2377,7 @@ H5O_obj_class(const H5O_loc_t *loc, hid_t dxpl_id)
     FUNC_ENTER_NOAPI_NOINIT_TAG(dxpl_id, loc->addr, NULL)
 
     /* Load the object header */
-    if(NULL == (oh = H5O_protect(loc, dxpl_id, H5AC_READ)))
+    if(NULL == (oh = H5O_protect(loc, dxpl_id, H5AC__READ_ONLY_FLAG)))
 	HGOTO_ERROR(H5E_OHDR, H5E_CANTPROTECT, NULL, "unable to load object header")
 
     /* Test whether entry qualifies as a particular type of object */
@@ -2671,7 +2674,7 @@ H5O_get_hdr_info(const H5O_loc_t *loc, hid_t dxpl_id, H5O_hdr_info_t *hdr)
     HDmemset(hdr, 0, sizeof(*hdr));
 
     /* Get the object header */
-    if(NULL == (oh = H5O_protect(loc, dxpl_id, H5AC_READ)))
+    if(NULL == (oh = H5O_protect(loc, dxpl_id, H5AC__READ_ONLY_FLAG)))
 	HGOTO_ERROR(H5E_OHDR, H5E_CANTLOAD, FAIL, "unable to load object header")
 
     /* Get the information for the object header */
@@ -2795,7 +2798,7 @@ H5O_get_info(const H5O_loc_t *loc, hid_t dxpl_id, hbool_t want_ih_info,
     HDassert(oinfo);
 
     /* Get the object header */
-    if(NULL == (oh = H5O_protect(loc, dxpl_id, H5AC_READ)))
+    if(NULL == (oh = H5O_protect(loc, dxpl_id, H5AC__READ_ONLY_FLAG)))
 	HGOTO_ERROR(H5E_OHDR, H5E_CANTPROTECT, FAIL, "unable to load object header")
 
     /* Reset the object info structure */
@@ -2916,7 +2919,7 @@ H5O_get_create_plist(const H5O_loc_t *loc, hid_t dxpl_id, H5P_genplist_t *oc_pli
     HDassert(oc_plist);
 
     /* Get the object header */
-    if(NULL == (oh = H5O_protect(loc, dxpl_id, H5AC_READ)))
+    if(NULL == (oh = H5O_protect(loc, dxpl_id, H5AC__READ_ONLY_FLAG)))
 	HGOTO_ERROR(H5E_OHDR, H5E_CANTPROTECT, FAIL, "unable to load object header")
 
     /* Set property values, if they were used for the object */
@@ -2971,7 +2974,7 @@ H5O_get_nlinks(const H5O_loc_t *loc, hid_t dxpl_id, hsize_t *nlinks)
     HDassert(nlinks);
 
     /* Get the object header */
-    if(NULL == (oh = H5O_protect(loc, dxpl_id, H5AC_READ)))
+    if(NULL == (oh = H5O_protect(loc, dxpl_id, H5AC__READ_ONLY_FLAG)))
 	HGOTO_ERROR(H5E_OHDR, H5E_CANTPROTECT, FAIL, "unable to load object header")
 
     /* Retrieve the # of link messages seen when the object header was loaded */
@@ -3088,7 +3091,7 @@ H5O_get_rc_and_type(const H5O_loc_t *loc, hid_t dxpl_id, unsigned *rc, H5O_type_
     HDassert(loc);
 
     /* Get the object header */
-    if(NULL == (oh = H5O_protect(loc, dxpl_id, H5AC_READ)))
+    if(NULL == (oh = H5O_protect(loc, dxpl_id, H5AC__READ_ONLY_FLAG)))
 	HGOTO_ERROR(H5E_OHDR, H5E_CANTPROTECT, FAIL, "unable to load object header")
 
     /* Set the object's reference count */
@@ -3461,7 +3464,7 @@ H5O_dec_rc_by_loc(const H5O_loc_t *loc, hid_t dxpl_id)
     HDassert(loc);
 
     /* Get header */
-    if(NULL == (oh = H5O_protect(loc, dxpl_id, H5AC_READ)))
+    if(NULL == (oh = H5O_protect(loc, dxpl_id, H5AC__READ_ONLY_FLAG)))
        HGOTO_ERROR(H5E_OHDR, H5E_CANTPROTECT, FAIL, "unable to protect object header")
 
     /* Decrement the reference count on the object header */
diff --git a/src/H5Oattribute.c b/src/H5Oattribute.c
index 46e7ce4..52f414b 100644
--- a/src/H5Oattribute.c
+++ b/src/H5Oattribute.c
@@ -483,7 +483,7 @@ H5O_attr_open_by_name(const H5O_loc_t *loc, const char *name, hid_t dxpl_id)
     HDassert(name);
 
     /* Protect the object header to iterate over */
-    if(NULL == (oh = H5O_protect(loc, dxpl_id, H5AC_READ)))
+    if(NULL == (oh = H5O_protect(loc, dxpl_id, H5AC__READ_ONLY_FLAG)))
 	HGOTO_ERROR(H5E_ATTR, H5E_CANTPROTECT, NULL, "unable to load object header")
 
     /* Check for attribute info stored */
@@ -632,7 +632,7 @@ H5O_attr_open_by_idx(const H5O_loc_t *loc, H5_index_t idx_type,
         HGOTO_ERROR(H5E_ATTR, H5E_BADITER, NULL, "can't locate attribute")
 
     /* Protect the object header to iterate over */
-    if(NULL == (oh = H5O_protect(loc, dxpl_id, H5AC_READ)))
+    if(NULL == (oh = H5O_protect(loc, dxpl_id, H5AC__READ_ONLY_FLAG)))
 	HGOTO_ERROR(H5E_ATTR, H5E_CANTPROTECT, NULL, "unable to load object header")
 
     /* Find out whether it has already been opened.  If it has, close the object
@@ -1283,7 +1283,7 @@ H5O_attr_iterate_real(hid_t loc_id, const H5O_loc_t *loc, hid_t dxpl_id,
     HDassert(attr_op);
 
     /* Protect the object header to iterate over */
-    if(NULL == (oh = H5O_protect(loc, dxpl_id, H5AC_READ)))
+    if(NULL == (oh = H5O_protect(loc, dxpl_id, H5AC__READ_ONLY_FLAG)))
 	HGOTO_ERROR(H5E_ATTR, H5E_CANTPROTECT, FAIL, "unable to load object header")
 
     /* Check for attribute info stored */
@@ -1846,7 +1846,7 @@ H5O_attr_exists(const H5O_loc_t *loc, const char *name, hid_t dxpl_id)
     HDassert(name);
 
     /* Protect the object header to iterate over */
-    if(NULL == (oh = H5O_protect(loc, dxpl_id, H5AC_READ)))
+    if(NULL == (oh = H5O_protect(loc, dxpl_id, H5AC__READ_ONLY_FLAG)))
 	HGOTO_ERROR(H5E_ATTR, H5E_CANTPROTECT, FAIL, "unable to load object header")
 
     /* Check for attribute info stored */
@@ -2000,7 +2000,7 @@ H5O_attr_count(const H5O_loc_t *loc, hid_t dxpl_id)
     HDassert(loc);
 
     /* Protect the object header to iterate over */
-    if(NULL == (oh = H5O_protect(loc, dxpl_id, H5AC_READ)))
+    if(NULL == (oh = H5O_protect(loc, dxpl_id, H5AC__READ_ONLY_FLAG)))
 	HGOTO_ERROR(H5E_ATTR, H5E_CANTPROTECT, FAIL, "unable to load object header")
 
     /* Retrieve # of attributes on object */
diff --git a/src/H5Ocache.c b/src/H5Ocache.c
index 816e06a..db1bd1f 100644
--- a/src/H5Ocache.c
+++ b/src/H5Ocache.c
@@ -68,17 +68,25 @@
 /********************/
 
 /* Metadata cache callbacks */
-static H5O_t *H5O_load(H5F_t *f, hid_t dxpl_id, haddr_t addr, void *udata);
-static herr_t H5O_flush(H5F_t *f, hid_t dxpl_id, hbool_t destroy, haddr_t addr, H5O_t *oh, unsigned H5_ATTR_UNUSED * flags_ptr);
-static herr_t H5O_dest(H5F_t *f, H5O_t *oh);
-static herr_t H5O_clear(H5F_t *f, H5O_t *oh, hbool_t destroy);
-static herr_t H5O_size(const H5F_t *f, const H5O_t *oh, size_t *size_ptr);
-
-static H5O_chunk_proxy_t *H5O_cache_chk_load(H5F_t *f, hid_t dxpl_id, haddr_t addr, void *udata);
-static herr_t H5O_cache_chk_flush(H5F_t *f, hid_t dxpl_id, hbool_t destroy, haddr_t addr, H5O_chunk_proxy_t *chk_proxy, unsigned H5_ATTR_UNUSED * flags_ptr);
-static herr_t H5O_cache_chk_dest(H5F_t *f, H5O_chunk_proxy_t *chk_proxy);
-static herr_t H5O_cache_chk_clear(H5F_t *f, H5O_chunk_proxy_t *chk_proxy, hbool_t destroy);
-static herr_t H5O_cache_chk_size(const H5F_t *f, const H5O_chunk_proxy_t *chk_proxy, size_t *size_ptr);
+static herr_t H5O__cache_get_load_size(const void *udata, size_t *image_len);
+static void *H5O__cache_deserialize(const void *image, size_t len,
+    void *udata, hbool_t *dirty); 
+static herr_t H5O__cache_image_len(const void *thing, size_t *image_len,
+    hbool_t *compressed_ptr, size_t *compressed_image_len_ptr);
+static herr_t H5O__cache_serialize(const H5F_t *f, void *image, size_t len,
+    void *thing); 
+static herr_t H5O__cache_free_icr(void *thing);
+static herr_t H5O__cache_clear(const H5F_t *f, void *thing, hbool_t about_to_destroy);
+
+static herr_t H5O__cache_chk_get_load_size(const void *udata, size_t *image_len);
+static void *H5O__cache_chk_deserialize(const void *image, size_t len,
+    void *udata, hbool_t *dirty); 
+static herr_t H5O__cache_chk_image_len(const void *thing, size_t *image_len,
+    hbool_t *compressed_ptr, size_t *compressed_image_len_ptr);
+static herr_t H5O__cache_chk_serialize(const H5F_t *f, void *image, size_t len,
+    void *thing);
+static herr_t H5O__cache_chk_free_icr(void *thing);
+static herr_t H5O__cache_chk_clear(const H5F_t *f, void *thing, hbool_t about_to_destroy);
 
 /* Chunk proxy routines */
 static herr_t H5O__chunk_proxy_dest(H5O_chunk_proxy_t *chunk_proxy);
@@ -99,24 +107,36 @@ static herr_t H5O__add_cont_msg(H5O_cont_msgs_t *cont_msg_info,
 
 /* H5O object header prefix inherits cache-like properties from H5AC */
 const H5AC_class_t H5AC_OHDR[1] = {{
-    H5AC_OHDR_ID,
-    (H5AC_load_func_t)H5O_load,
-    (H5AC_flush_func_t)H5O_flush,
-    (H5AC_dest_func_t)H5O_dest,
-    (H5AC_clear_func_t)H5O_clear,
-    (H5AC_notify_func_t)NULL,
-    (H5AC_size_func_t)H5O_size,
+    H5AC_OHDR_ID,                       /* Metadata client ID */
+    "object header",                    /* Metadata client name (for debugging) */
+    H5FD_MEM_OHDR,                      /* File space memory type for client */
+    H5AC__CLASS_SPECULATIVE_LOAD_FLAG,  /* Client class behavior flags */
+    H5O__cache_get_load_size,           /* 'get_load_size' callback */
+    H5O__cache_deserialize,             /* 'deserialize' callback */
+    H5O__cache_image_len,               /* 'image_len' callback */
+    NULL,                               /* 'pre_serialize' callback */
+    H5O__cache_serialize,               /* 'serialize' callback */
+    NULL,                               /* 'notify' callback */
+    H5O__cache_free_icr,                /* 'free_icr' callback */
+    H5O__cache_clear,                   /* 'clear' callback */
+    NULL,                               /* 'fsf_size' callback */
 }};
 
 /* H5O object header chunk inherits cache-like properties from H5AC */
 const H5AC_class_t H5AC_OHDR_CHK[1] = {{
-    H5AC_OHDR_CHK_ID,
-    (H5AC_load_func_t)H5O_cache_chk_load,
-    (H5AC_flush_func_t)H5O_cache_chk_flush,
-    (H5AC_dest_func_t)H5O_cache_chk_dest,
-    (H5AC_clear_func_t)H5O_cache_chk_clear,
-    (H5AC_notify_func_t)NULL,
-    (H5AC_size_func_t)H5O_cache_chk_size,
+    H5AC_OHDR_CHK_ID,                   /* Metadata client ID */
+    "object header continuation chunk", /* Metadata client name (for debugging) */
+    H5FD_MEM_OHDR,                      /* File space memory type for client */
+    H5AC__CLASS_NO_FLAGS_SET,           /* Client class behavior flags */
+    H5O__cache_chk_get_load_size,       /* 'get_load_size' callback */
+    H5O__cache_chk_deserialize,         /* 'deserialize' callback */
+    H5O__cache_chk_image_len,           /* 'image_len' callback */
+    NULL,                               /* 'pre_serialize' callback */
+    H5O__cache_chk_serialize,           /* 'serialize' callback */
+    NULL,                               /* 'notify' callback */
+    H5O__cache_chk_free_icr,            /* 'free_icr' callback */
+    H5O__cache_chk_clear,               /* 'clear' callback */
+    NULL,                               /* 'fsf_size' callback */
 }};
 
 /* Declare external the free list for H5O_unknown_t's */
@@ -141,55 +161,75 @@ H5FL_SEQ_DEFINE(H5O_cont_t);
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5O_load
+ * Function:    H5O__cache_get_load_size()
  *
- * Purpose:	Loads an object header from disk.
+ * Purpose:	Tell the metadata cache how much data to read from file in 
+ *		the first speculative read for the object header.  Note that we do 
+ *		not have to be concerned about reading past the end of file, as the 
+ *		cache will clamp the read to avoid this if needed.
  *
- * Return:	Success:	Pointer to the new object header.
+ * Return:      Success:        SUCCEED
+ *              Failure:        FAIL
  *
- *		Failure:	NULL
+ * Programmer:  John Mainzer
+ *              7/28/14
  *
- * Programmer:	Robb Matzke
- *		matzke@llnl.gov
- *		Aug  5 1997
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+H5O__cache_get_load_size(const void H5_ATTR_UNUSED *_udata, size_t *image_len)
+{
+    FUNC_ENTER_STATIC_NOERR
+
+    /* Check arguments */
+    HDassert(image_len);
+
+    *image_len = H5O_SPEC_READ_SIZE;
+
+    FUNC_LEAVE_NOAPI(SUCCEED)
+} /* end H5O__cache_get_load_size() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:    H5O__cache_deserialize
+ *
+ * Purpose:	Attempt to deserialize the object header contained in the 
+ *		supplied buffer, load the data into an instance of H5O_t, and 
+ *		return a pointer to the new instance.
+ *
+ *		Note that the object header is read with with a speculative read.  
+ *		If the initial read is too small, make note of this fact and return 
+ *     		without error.  H5C_load_entry() will note the size discrepency
+ *		and retry the deserialize operation with the correct size read.
+ *
+ * Return:      Success:        Pointer to in core representation
+ *              Failure:        NULL
+ *
+ * Programmer:  John Mainzer
+ *              7/28/14
  *
  *-------------------------------------------------------------------------
  */
-static H5O_t *
-H5O_load(H5F_t *f, hid_t dxpl_id, haddr_t addr, void *_udata)
+static void *
+H5O__cache_deserialize(const void *_image, size_t len, void *_udata,
+    hbool_t *dirty)
 {
-    H5O_t	*oh = NULL;     /* Object header read in */
-    H5O_cache_ud_t *udata = (H5O_cache_ud_t *)_udata;       /* User data for callback */
-    H5WB_t      *wb = NULL;     /* Wrapped buffer for prefix data */
-    uint8_t     read_buf[H5O_SPEC_READ_SIZE];       /* Buffer for speculative read */
-    const uint8_t *p;           /* Pointer into buffer to decode */
-    uint8_t     *buf;           /* Buffer to decode */
-    size_t	spec_read_size; /* Size of buffer to speculatively read in */
-    size_t	prefix_size;    /* Size of object header prefix */
-    size_t	buf_size;       /* Size of prefix+chunk #0 buffer */
-    haddr_t     eoa;		/* Relative end of file address	*/
-    H5O_t	*ret_value;     /* Return value */
-
-    FUNC_ENTER_NOAPI_NOINIT
+    H5O_t          *oh = NULL;          /* Object header read in */
+    H5O_cache_ud_t *udata = (H5O_cache_ud_t *)_udata;   /* User data for callback */
+    const uint8_t  *image = (const uint8_t *)_image;    /* Pointer into buffer to decode */
+    size_t          prefix_size;        /* Size of object header prefix */
+    size_t          buf_size;           /* Size of prefix+chunk #0 buffer */
+    void *          ret_value = NULL;   /* Return value */
+
+    FUNC_ENTER_STATIC
 
     /* Check arguments */
-    HDassert(f);
-    HDassert(H5F_addr_defined(addr));
+    HDassert(image);
+    HDassert(len > 0); 
     HDassert(udata);
     HDassert(udata->common.f);
     HDassert(udata->common.cont_msg_info);
-
-    /* Make certain we don't speculatively read off the end of the file */
-    if(HADDR_UNDEF == (eoa = H5F_get_eoa(f, H5FD_MEM_OHDR)))
-        HGOTO_ERROR(H5E_OHDR, H5E_CANTGET, NULL, "unable to determine file size")
-
-    /* Compute the size of the speculative object header buffer */
-    H5_CHECKED_ASSIGN(spec_read_size, size_t, MIN(eoa - addr, H5O_SPEC_READ_SIZE), hsize_t);
-
-    /* Attempt to speculatively read both object header prefix and first chunk */
-    if(H5F_block_read(f, H5FD_MEM_OHDR, addr, spec_read_size, dxpl_id, read_buf) < 0)
-	HGOTO_ERROR(H5E_OHDR, H5E_READERROR, NULL, "unable to read object header")
-    p = read_buf;
+    HDassert(dirty);
 
     /* Allocate space for the object header data structure */
     if(NULL == (oh = H5FL_CALLOC(H5O_t)))
@@ -201,18 +241,18 @@ H5O_load(H5F_t *f, hid_t dxpl_id, haddr_t addr, void *_udata)
 
     /* Check for presence of magic number */
     /* (indicates version 2 or later) */
-    if(!HDmemcmp(p, H5O_HDR_MAGIC, (size_t)H5_SIZEOF_MAGIC)) {
+    if(!HDmemcmp(image, H5O_HDR_MAGIC, (size_t)H5_SIZEOF_MAGIC)) {
         /* Magic number */
-        p += H5_SIZEOF_MAGIC;
+        image += H5_SIZEOF_MAGIC;
 
         /* Version */
-        oh->version = *p++;
-        if(H5O_VERSION_2 != oh->version)
+        oh->version = *image++;
+        if(H5O_VERSION_2 != oh->version) 
             HGOTO_ERROR(H5E_OHDR, H5E_VERSION, NULL, "bad object header version number")
 
         /* Flags */
-        oh->flags = *p++;
-        if(oh->flags & ~H5O_HDR_ALL_FLAGS)
+        oh->flags = *image++;
+        if(oh->flags & ~H5O_HDR_ALL_FLAGS) 
             HGOTO_ERROR(H5E_OHDR, H5E_BADVALUE, NULL, "unknown object header status flag(s)")
 
         /* Number of links to object (unless overridden by refcount message) */
@@ -222,13 +262,13 @@ H5O_load(H5F_t *f, hid_t dxpl_id, haddr_t addr, void *_udata)
         if(oh->flags & H5O_HDR_STORE_TIMES) {
             uint32_t tmp;       /* Temporary value */
 
-            UINT32DECODE(p, tmp);
+            UINT32DECODE(image, tmp);
             oh->atime = (time_t)tmp;
-            UINT32DECODE(p, tmp);
+            UINT32DECODE(image, tmp);
             oh->mtime = (time_t)tmp;
-            UINT32DECODE(p, tmp);
+            UINT32DECODE(image, tmp);
             oh->ctime = (time_t)tmp;
-            UINT32DECODE(p, tmp);
+            UINT32DECODE(image, tmp);
             oh->btime = (time_t)tmp;
         } /* end if */
         else
@@ -236,8 +276,9 @@ H5O_load(H5F_t *f, hid_t dxpl_id, haddr_t addr, void *_udata)
 
         /* Attribute fields */
         if(oh->flags & H5O_HDR_ATTR_STORE_PHASE_CHANGE) {
-            UINT16DECODE(p, oh->max_compact);
-            UINT16DECODE(p, oh->min_dense);
+            UINT16DECODE(image, oh->max_compact);
+            UINT16DECODE(image, oh->min_dense);
+
             if(oh->max_compact < oh->min_dense)
                 HGOTO_ERROR(H5E_OHDR, H5E_BADVALUE, NULL, "bad object header attribute phase change values")
         } /* end if */
@@ -249,19 +290,19 @@ H5O_load(H5F_t *f, hid_t dxpl_id, haddr_t addr, void *_udata)
         /* First chunk size */
         switch(oh->flags & H5O_HDR_CHUNK0_SIZE) {
             case 0:     /* 1 byte size */
-                oh->chunk0_size = *p++;
+                oh->chunk0_size = *image++;
                 break;
 
             case 1:     /* 2 byte size */
-                UINT16DECODE(p, oh->chunk0_size);
+                UINT16DECODE(image, oh->chunk0_size);
                 break;
 
             case 2:     /* 4 byte size */
-                UINT32DECODE(p, oh->chunk0_size);
+                UINT32DECODE(image, oh->chunk0_size);
                 break;
 
             case 3:     /* 8 byte size */
-                UINT64DECODE(p, oh->chunk0_size);
+                UINT64DECODE(image, oh->chunk0_size);
                 break;
 
             default:
@@ -272,7 +313,7 @@ H5O_load(H5F_t *f, hid_t dxpl_id, haddr_t addr, void *_udata)
     } /* end if */
     else {
         /* Version */
-        oh->version = *p++;
+        oh->version = *image++;
         if(H5O_VERSION_1 != oh->version)
             HGOTO_ERROR(H5E_OHDR, H5E_VERSION, NULL, "bad object header version number")
 
@@ -280,13 +321,13 @@ H5O_load(H5F_t *f, hid_t dxpl_id, haddr_t addr, void *_udata)
         oh->flags = H5O_CRT_OHDR_FLAGS_DEF;
 
         /* Reserved */
-        p++;
+        image++;
 
         /* Number of messages */
-        UINT16DECODE(p, udata->v1_pfx_nmesgs);
+        UINT16DECODE(image, udata->v1_pfx_nmesgs);
 
         /* Link count */
-        UINT32DECODE(p, oh->nlink);
+        UINT32DECODE(image, oh->nlink);
 
         /* Reset unused time fields */
         oh->atime = oh->mtime = oh->ctime = oh->btime = 0;
@@ -296,45 +337,36 @@ H5O_load(H5F_t *f, hid_t dxpl_id, haddr_t addr, void *_udata)
         oh->min_dense = 0;
 
         /* First chunk size */
-        UINT32DECODE(p, oh->chunk0_size);
-        if((udata->v1_pfx_nmesgs > 0 && oh->chunk0_size < H5O_SIZEOF_MSGHDR_OH(oh)) ||
-                (udata->v1_pfx_nmesgs == 0 && oh->chunk0_size > 0))
+        UINT32DECODE(image, oh->chunk0_size);
+
+        if((udata->v1_pfx_nmesgs > 0 && 
+                oh->chunk0_size < H5O_SIZEOF_MSGHDR_OH(oh)) ||
+                    (udata->v1_pfx_nmesgs == 0 && oh->chunk0_size > 0))
             HGOTO_ERROR(H5E_OHDR, H5E_BADVALUE, NULL, "bad object header chunk size")
 
         /* Reserved, in version 1 (for 8-byte alignment padding) */
-        p += 4;
+        image += 4;
     } /* end else */
 
     /* Determine object header prefix length */
-    prefix_size = (size_t)(p - (const uint8_t *)read_buf);
+    prefix_size = (size_t)(image - (const uint8_t *)_image);
     HDassert((size_t)prefix_size == (size_t)(H5O_SIZEOF_HDR(oh) - H5O_SIZEOF_CHKSUM_OH(oh)));
 
     /* Compute the size of the buffer used */
     buf_size = oh->chunk0_size + (size_t)H5O_SIZEOF_HDR(oh);
 
-    /* Check if the speculative read was large enough to parse the first chunk */
-    if(spec_read_size < buf_size) {
-        /* Wrap the local buffer for serialized header info */
-        if(NULL == (wb = H5WB_wrap(read_buf, sizeof(read_buf))))
-            HGOTO_ERROR(H5E_OHDR, H5E_CANTINIT, NULL, "can't wrap buffer")
-
-        /* Get a pointer to a buffer that's large enough for serialized header */
-        if(NULL == (buf = (uint8_t *)H5WB_actual(wb, buf_size)))
-            HGOTO_ERROR(H5E_OHDR, H5E_NOSPACE, NULL, "can't get actual buffer")
-
-        /* Copy existing raw data into new buffer */
-        HDmemcpy(buf, read_buf, spec_read_size);
-
-        /* Read rest of the raw data */
-        if(H5F_block_read(f, H5FD_MEM_OHDR, (addr + spec_read_size), (buf_size - spec_read_size), dxpl_id, (buf + spec_read_size)) < 0)
-            HGOTO_ERROR(H5E_OHDR, H5E_READERROR, NULL, "unable to read object header data")
+    /* Check to see if the buffer provided is large enough to contain both 
+     * the prefix and the first chunk.  If it isn't, make note of the desired
+     * size, but otherwise do nothing.  H5C_load_entry() will notice the 
+     * discrepency, load the correct size buffer, and retry the deserialize.
+     */
+    if(len >= buf_size) {
+        /* Parse the first chunk */
+        if(H5O__chunk_deserialize(oh, udata->common.addr, oh->chunk0_size, (const uint8_t *)_image, &(udata->common), dirty) < 0)
+            HGOTO_ERROR(H5E_OHDR, H5E_CANTINIT, NULL, "can't deserialize first object header chunk")
     } /* end if */
     else
-        buf = read_buf;
-
-    /* Parse the first chunk */
-    if(H5O__chunk_deserialize(oh, udata->common.addr, oh->chunk0_size, buf, &(udata->common), &oh->cache_info.is_dirty) < 0)
-        HGOTO_ERROR(H5E_OHDR, H5E_CANTINIT, NULL, "can't deserialize first object header chunk")
+        HDassert(!udata->made_attempt);
 
     /* Note that we've loaded the object header from the file */
     udata->made_attempt = TRUE;
@@ -343,202 +375,234 @@ H5O_load(H5F_t *f, hid_t dxpl_id, haddr_t addr, void *_udata)
     ret_value = oh;
 
 done:
-    /* Release resources */
-    if(wb && H5WB_unwrap(wb) < 0)
-        HDONE_ERROR(H5E_OHDR, H5E_CLOSEERROR, NULL, "can't close wrapped buffer")
-
     /* Release the [possibly partially initialized] object header on errors */
     if(!ret_value && oh)
         if(H5O_free(oh) < 0)
             HDONE_ERROR(H5E_OHDR, H5E_CANTRELEASE, NULL, "unable to destroy object header data")
 
     FUNC_LEAVE_NOAPI(ret_value)
-} /* end H5O_load() */
+} /* end H5O__cache_deserialize() */
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5O_flush
+ * Function:    H5O__cache_image_len
  *
- * Purpose:	Flushes (and destroys) an object header.
+ * Purpose:	Compute the size in bytes of the specified instance of
+ *		H5O_t on disk, and return it in *image_len.  On failure,
+ *		the value of *image_len is undefined.
  *
- * Return:	Non-negative on success/Negative on failure
+ * Return:      Success:        SUCCEED
+ *              Failure:        FAIL
  *
- * Programmer:	Robb Matzke
- *		matzke@llnl.gov
- *		Aug  5 1997
+ * Programmer:  John Mainzer
+ *              7/28/14
  *
  *-------------------------------------------------------------------------
  */
 static herr_t
-H5O_flush(H5F_t *f, hid_t dxpl_id, hbool_t destroy, haddr_t H5_ATTR_UNUSED addr, H5O_t *oh, unsigned H5_ATTR_UNUSED * flags_ptr)
+H5O__cache_image_len(const void *_thing, size_t *image_len,
+    hbool_t H5_ATTR_UNUSED *compressed_ptr, size_t H5_ATTR_UNUSED *compressed_image_len_ptr)
 {
-    herr_t ret_value = SUCCEED; /* Return value */
+    const H5O_t *oh = (const H5O_t *)_thing;    /* Object header to query */
 
-    FUNC_ENTER_NOAPI_NOINIT
+    FUNC_ENTER_STATIC_NOERR
 
     /* Check arguments */
-    HDassert(f);
-    HDassert(H5F_addr_defined(addr));
     HDassert(oh);
+    HDassert(oh->cache_info.magic == H5C__H5C_CACHE_ENTRY_T_MAGIC);
+    HDassert(oh->cache_info.type == H5AC_OHDR);
+    HDassert(image_len);
+
+    /* Report the object header's prefix+first chunk length */
+    if(oh->chunk0_size)
+       *image_len = (size_t)H5O_SIZEOF_HDR(oh) + oh->chunk0_size;
+    else
+       *image_len = oh->chunk[0].size;
+
+    FUNC_LEAVE_NOAPI(SUCCEED)
+} /* end H5O__cache_image_len() */
 
-    /* flush */
-    if(oh->cache_info.is_dirty) {
-        uint8_t	*p;             /* Pointer to object header prefix buffer */
+/********************************/
+/* no H5O_cache_pre_serialize() */
+/********************************/
 
+
+/*-------------------------------------------------------------------------
+ * Function:    H5O__cache_serialize
+ *
+ * Purpose:	Serialize the contents of the supplied object header, and
+ *		load this data into the supplied buffer.
+ *
+ * Return:      Success:        SUCCEED
+ *              Failure:        FAIL
+ *
+ * Programmer:  John Mainzer
+ *              7/28/14
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+H5O__cache_serialize(const H5F_t *f, void *image, size_t len, void *_thing)
+{
+    H5O_t      *oh = (H5O_t *)_thing;   /* Object header to encode */
+    uint8_t     *chunk_image;           /* Pointer to object header prefix buffer */
+    herr_t      ret_value = SUCCEED;    /* Return value */
+
+    FUNC_ENTER_STATIC
+
+    /* Check arguments */
+    HDassert(f);
+    HDassert(image);
+    HDassert(oh);
+    HDassert(oh->cache_info.magic == H5C__H5C_CACHE_ENTRY_T_MAGIC);
+    HDassert(oh->cache_info.type == H5AC_OHDR);
+    HDassert(oh->chunk[0].size == len);
 #ifdef H5O_DEBUG
-H5O_assert(oh);
+    H5O_assert(oh);
 #endif /* H5O_DEBUG */
 
-        /* Point to raw data 'image' for first chunk, which has room for the prefix */
-        p = oh->chunk[0].image;
-
-        /* Later versions of object header prefix have different format and
-         * also require that chunk 0 always be updated, since the checksum
-         * on the entire block of memory needs to be updated if anything is
-         * modified */
-        if(oh->version > H5O_VERSION_1) {
-            uint64_t chunk0_size;       /* Size of chunk 0's data */
+    /* Point to raw data 'image' for first chunk, which 
+     * has room for the prefix 
+     */
+    chunk_image = oh->chunk[0].image;
 
-            HDassert(oh->chunk[0].size >= (size_t)H5O_SIZEOF_HDR(oh));
-            chunk0_size = oh->chunk[0].size - (size_t)H5O_SIZEOF_HDR(oh);
+    /* Later versions of object header prefix have different format and
+     * also require that chunk 0 always be updated, since the checksum
+     * on the entire block of memory needs to be updated if anything is
+     * modified 
+     */
+    if(oh->version > H5O_VERSION_1) {
+        uint64_t chunk0_size;       /* Size of chunk 0's data */
 
-            /* Verify magic number */
-            HDassert(!HDmemcmp(p, H5O_HDR_MAGIC, H5_SIZEOF_MAGIC));
-            p += H5_SIZEOF_MAGIC;
+        HDassert(oh->chunk[0].size >= (size_t)H5O_SIZEOF_HDR(oh));
+        chunk0_size = oh->chunk[0].size - (size_t)H5O_SIZEOF_HDR(oh);
 
-            /* Version */
-            *p++ = oh->version;
+        /* Verify magic number */
+        HDassert(!HDmemcmp(chunk_image, H5O_HDR_MAGIC, H5_SIZEOF_MAGIC));
+        chunk_image += H5_SIZEOF_MAGIC;
 
-            /* Flags */
-            *p++ = oh->flags;
+        /* Version */
+        *chunk_image++ = oh->version;
 
-            /* Time fields */
-            if(oh->flags & H5O_HDR_STORE_TIMES) {
-                UINT32ENCODE(p, oh->atime);
-                UINT32ENCODE(p, oh->mtime);
-                UINT32ENCODE(p, oh->ctime);
-                UINT32ENCODE(p, oh->btime);
-            } /* end if */
+        /* Flags */
+        *chunk_image++ = oh->flags;
 
-            /* Attribute fields */
-            if(oh->flags & H5O_HDR_ATTR_STORE_PHASE_CHANGE) {
-                UINT16ENCODE(p, oh->max_compact);
-                UINT16ENCODE(p, oh->min_dense);
-            } /* end if */
+        /* Time fields */
+        if(oh->flags & H5O_HDR_STORE_TIMES) {
+            UINT32ENCODE(chunk_image, oh->atime);
+            UINT32ENCODE(chunk_image, oh->mtime);
+            UINT32ENCODE(chunk_image, oh->ctime);
+            UINT32ENCODE(chunk_image, oh->btime);
+        } /* end if */
 
-            /* First chunk size */
-            switch(oh->flags & H5O_HDR_CHUNK0_SIZE) {
-                case 0:     /* 1 byte size */
-                    HDassert(chunk0_size < 256);
-                    *p++ = (uint8_t)chunk0_size;
-                    break;
-
-                case 1:     /* 2 byte size */
-                    HDassert(chunk0_size < 65536);
-                    UINT16ENCODE(p, chunk0_size);
-                    break;
-
-                case 2:     /* 4 byte size */
-		    /* use <= 2**32 -1 to stay within 4 bytes integer range */
-                    HDassert(chunk0_size <= 4294967295UL);
-                    UINT32ENCODE(p, chunk0_size);
-                    break;
-
-                case 3:     /* 8 byte size */
-                    UINT64ENCODE(p, chunk0_size);
-                    break;
-
-                default:
-                    HGOTO_ERROR(H5E_OHDR, H5E_BADVALUE, FAIL, "bad size for chunk 0")
-            } /* end switch */
+        /* Attribute fields */
+        if(oh->flags & H5O_HDR_ATTR_STORE_PHASE_CHANGE) {
+            UINT16ENCODE(chunk_image, oh->max_compact);
+            UINT16ENCODE(chunk_image, oh->min_dense);
         } /* end if */
-        else {
-            /* Version */
-            *p++ = oh->version;
 
-            /* Reserved */
-            *p++ = 0;
+        /* First chunk size */
+        switch(oh->flags & H5O_HDR_CHUNK0_SIZE) {
+            case 0:     /* 1 byte size */
+                HDassert(chunk0_size < 256);
+                *chunk_image++ = (uint8_t)chunk0_size;
+                break;
+
+            case 1:     /* 2 byte size */
+                HDassert(chunk0_size < 65536);
+                UINT16ENCODE(chunk_image, chunk0_size);
+                break;
+
+            case 2:     /* 4 byte size */
+                /* use <= 2**32 -1 to stay within 4 bytes integer range */
+                HDassert(chunk0_size <= 4294967295UL);
+                UINT32ENCODE(chunk_image, chunk0_size);
+                break;
 
-            /* Number of messages */
+            case 3:     /* 8 byte size */
+                UINT64ENCODE(chunk_image, chunk0_size);
+                break;
+
+            default:
+                HGOTO_ERROR(H5E_OHDR, H5E_BADVALUE, FAIL, "bad size for chunk 0")
+        } /* end switch */
+    } /* end if */
+    else {
+        /* Version */
+        *chunk_image++ = oh->version;
+
+        /* Reserved */
+        *chunk_image++ = 0;
+
+        /* Number of messages */
 #ifdef H5O_ENABLE_BAD_MESG_COUNT
-            if(oh->store_bad_mesg_count)
-                UINT16ENCODE(p, (oh->nmesgs - 1))
-            else
+        if(oh->store_bad_mesg_count)
+           UINT16ENCODE(chunk_image, (oh->nmesgs - 1))
+        else
 #endif /* H5O_ENABLE_BAD_MESG_COUNT */
-                UINT16ENCODE(p, oh->nmesgs);
-
-            /* Link count */
-            UINT32ENCODE(p, oh->nlink);
+            UINT16ENCODE(chunk_image, oh->nmesgs);
 
-            /* First chunk size */
-            UINT32ENCODE(p, (oh->chunk[0].size - (size_t)H5O_SIZEOF_HDR(oh)));
+        /* Link count */
+        UINT32ENCODE(chunk_image, oh->nlink);
 
-            /* Zero to alignment */
-            HDmemset(p, 0, (size_t)(H5O_SIZEOF_HDR(oh) - 12));
-            p += (size_t)(H5O_SIZEOF_HDR(oh) - 12);
-        } /* end else */
-        HDassert((size_t)(p - oh->chunk[0].image) == (size_t)(H5O_SIZEOF_HDR(oh) - H5O_SIZEOF_CHKSUM_OH(oh)));
+        /* First chunk size */
+        UINT32ENCODE(chunk_image, (oh->chunk[0].size - (size_t)H5O_SIZEOF_HDR(oh)));
 
-        /* Serialize messages for this chunk */
-        if(H5O__chunk_serialize(f, oh, (unsigned)0) < 0)
-            HGOTO_ERROR(H5E_OHDR, H5E_CANTSERIALIZE, FAIL, "unable to serialize first object header chunk")
+        /* Zero to alignment */
+        HDmemset(chunk_image, 0, (size_t)(H5O_SIZEOF_HDR(oh) - 12));
+        chunk_image += (size_t)(H5O_SIZEOF_HDR(oh) - 12);
+    } /* end else */
 
-        /* Write the chunk out */
-        HDassert(H5F_addr_defined(oh->chunk[0].addr));
-        if(H5F_block_write(f, H5FD_MEM_OHDR, oh->chunk[0].addr, oh->chunk[0].size, dxpl_id, oh->chunk[0].image) < 0)
-            HGOTO_ERROR(H5E_OHDR, H5E_WRITEERROR, FAIL, "unable to write object header chunk to disk")
+    HDassert((size_t)(chunk_image - oh->chunk[0].image) == (size_t)(H5O_SIZEOF_HDR(oh) - H5O_SIZEOF_CHKSUM_OH(oh)));
 
-        /* Mark object header as clean now */
-	oh->cache_info.is_dirty = FALSE;
-    } /* end if */
+    /* Serialize messages for this chunk */
+    if(H5O__chunk_serialize(f, oh, (unsigned)0) < 0) 
+        HGOTO_ERROR(H5E_OHDR, H5E_CANTSERIALIZE, FAIL, "unable to serialize first object header chunk")
 
-    /* Destroy the object header, if requested */
-    if(destroy)
-        if(H5O_dest(f, oh) < 0)
-	    HGOTO_ERROR(H5E_OHDR, H5E_CANTFREE, FAIL, "unable to destroy object header data")
+    /* copy the chunk into the image -- this is potentially expensive.  
+     * Can we rework things so that the object header and the cache 
+     * share a buffer?
+     */
+    HDmemcpy(image, oh->chunk[0].image, len);
 
 done:
     FUNC_LEAVE_NOAPI(ret_value)
-} /* end H5O_flush() */
+} /* end H5O__cache_serialize() */
+
+/**********************************/
+/* no H5O_cache_notify() function */
+/**********************************/
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5O_dest
+ * Function:    H5O__cache_free_icr
  *
- * Purpose:	Destroys an object header.
+ * Purpose:	Free the in core representation of the supplied object header.
  *
- * Return:	Non-negative on success/Negative on failure
+ * Note:	The metadata cache sets the object's cache_info.magic to
+ *		H5C__H5C_CACHE_ENTRY_T_BAD_MAGIC before calling a free_icr
+ *		callback (checked in assert).
  *
- * Programmer:	Quincey Koziol
- *		koziol@ncsa.uiuc.edu
- *		Jan 15 2003
+ * Return:      Success:        SUCCEED
+ *              Failure:        FAIL
+ *
+ * Programmer:  John Mainzer
+ *              7/28/14
  *
  *-------------------------------------------------------------------------
  */
 static herr_t
-H5O_dest(H5F_t *f, H5O_t *oh)
-{
-    herr_t ret_value = SUCCEED;         /* Return value */
+H5O__cache_free_icr(void *_thing)
+{ 
+    H5O_t      *oh = (H5O_t *)_thing;   /* Object header to destroy */
+    herr_t      ret_value = SUCCEED;    /* Return value */
 
-    FUNC_ENTER_NOAPI_NOINIT
+    FUNC_ENTER_STATIC
 
     /* Check arguments */
     HDassert(oh);
-    HDassert(oh->rc == 0);
-
-    /* Verify that node is clean */
-    HDassert(!oh->cache_info.is_dirty);
-
-    /* If we're going to free the space on disk, the address must be valid */
-    HDassert(!oh->cache_info.free_file_space_on_destroy || H5F_addr_defined(oh->cache_info.addr));
-
-    /* Check for releasing file space for object header */
-    if(oh->chunk && oh->cache_info.free_file_space_on_destroy) {
-        /* Free main (first) object header "chunk" */
-        /* (XXX: Nasty usage of internal DXPL value! -QAK) */
-        if(H5MF_xfree(f, H5FD_MEM_OHDR, H5AC_dxpl_id, oh->chunk[0].addr, (hsize_t)oh->chunk[0].size) < 0)
-            HGOTO_ERROR(H5E_OHDR, H5E_CANTFREE, FAIL, "unable to free object header")
-    } /* end if */
+    HDassert(oh->cache_info.magic == H5C__H5C_CACHE_ENTRY_T_BAD_MAGIC);
+    HDassert(oh->cache_info.type == H5AC_OHDR);
 
     /* Destroy object header */
     if(H5O_free(oh) < 0)
@@ -546,170 +610,143 @@ H5O_dest(H5F_t *f, H5O_t *oh)
 
 done:
     FUNC_LEAVE_NOAPI(ret_value)
-} /* end H5O_dest() */
+} /* end H5O__cache_free_icr() */
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5O_clear
+ * Function:    H5O__cache_clear
  *
- * Purpose:	Mark a object header in memory as non-dirty.
+ * Purpose: 	Clear all dirty bits associated with this cache entry.
  *
- * Return:	Non-negative on success/Negative on failure
+ *		This is ncessary as the object header cache client maintains 
+ *		its own dirty bits on individual messages.  These dirty bits 
+ *		used to be cleared by the old V2 metadata cache flush callback,
+ *		but now the metadata cache must clear them explicitly, as 
+ *		the serialize callback does not imply that the data has been
+ *		written to disk.
  *
- * Programmer:	Quincey Koziol
- *		koziol@ncsa.uiuc.edu
- *		Mar 20 2003
- *
- * Changes:     In the parallel case, there is the possibility that the
- *              the object header may be flushed by different processes
- *              over the life of the computation.  Thus we must ensure
- *              that the chunk images are up to date before we mark the
- *              messages clean -- as otherwise we may overwrite valid
- *              data with a blank section of a chunk image.
+ *		This callback is also necessary for the parallel case.
  *
- *              To deal with this, I have added code to call
- *              H5O_chunk_serialize() for all chunks before we
- *              mark all messages as clean if we are not destroying the
- *              object.  Do this in the parallel case only, as the problem
- *              can only occur in this context.
+ * Return:      Success:        SUCCEED
+ *              Failure:        FAIL
  *
- *                                              JRM -- 10/12/10
+ * Programmer:  John Mainzer
+ *              9/22/14
  *
  *-------------------------------------------------------------------------
  */
 static herr_t
-H5O_clear(H5F_t *f, H5O_t *oh, hbool_t destroy)
-{
-    unsigned	u;      /* Local index variable */
-    herr_t ret_value = SUCCEED;
+H5O__cache_clear(const H5F_t *f, void *_thing, hbool_t about_to_destroy)
+{ 
+    H5O_t      *oh = (H5O_t *)_thing;   /* Object header to reset */
+    unsigned    u;                      /* Local index variable */
+    herr_t      ret_value = SUCCEED;    /* Return value */
 
-    FUNC_ENTER_NOAPI_NOINIT
+    FUNC_ENTER_STATIC
 
     /* Check arguments */
     HDassert(oh);
+    HDassert(oh->cache_info.magic == H5C__H5C_CACHE_ENTRY_T_MAGIC);
+    HDassert(oh->cache_info.type == H5AC_OHDR);
 
 #ifdef H5_HAVE_PARALLEL
-    if ( ( oh->cache_info.is_dirty ) && ( ! destroy ) ) {
-
-        size_t i;
-
-        /* scan through all chunks associated with the object header,
-         * and cause them to update their images for all entries currently
-         * marked dirty.  Must do this in the parallel case, as it is possible
-         * that this processor may clear this object header several times
-         * before flushing it -- thus causing undefined sections of the image
-         * to be written to disk overwriting valid data.
+    if((oh->nchunks > 0) && (!about_to_destroy)) {
+        /* Scan through chunk 0 (the chunk stored contiguously with this 
+         * object header) and cause it to update its image of all entries 
+         * currently marked dirty.  Must do this in the parallel case, as 
+         * it is possible that this processor may clear this object header 
+         * several times before flushing it -- thus causing undefined 
+         * sections of the image to be written to disk overwriting valid data.
          */
-
-        for ( i = 0; i < oh->nchunks; i++ ) {
-
-            if(H5O__chunk_serialize(f, oh, i) < 0)
-                HGOTO_ERROR(H5E_OHDR, H5E_CANTSERIALIZE, FAIL, "unable to serialize object header chunk")
-        }
-    }
+        if(H5O__chunk_serialize(f, oh, 0) < 0)
+            HGOTO_ERROR(H5E_OHDR, H5E_CANTSERIALIZE, FAIL, "unable to serialize object header chunk")
+    } /* end if */
 #endif /* H5_HAVE_PARALLEL */
 
     /* Mark messages stored with the object header (i.e. messages in chunk 0) as clean */
     for(u = 0; u < oh->nmesgs; u++)
-        oh->mesg[u].dirty = FALSE;
+        if(oh->mesg[u].chunkno == 0)
+            oh->mesg[u].dirty = FALSE;
 
 #ifndef NDEBUG
     /* Reset the number of messages dirtied by decoding */
     oh->ndecode_dirtied = 0;
 #endif /* NDEBUG */
 
-    /* Mark whole header as clean */
-    oh->cache_info.is_dirty = FALSE;
-
-    if(destroy)
-        if(H5O_dest(f, oh) < 0)
-            HGOTO_ERROR(H5E_OHDR, H5E_CANTFREE, FAIL, "unable to destroy object header data")
-
 done:
     FUNC_LEAVE_NOAPI(ret_value)
-} /* end H5O_clear() */
+} /* end H5O__cache_clear() */
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5O_size
+ * Function:    H5O__cache_chk_get_load_size()
  *
- * Purpose:	Compute the size in bytes of the specified instance of
- *              H5O_t on disk, and return it in *len_ptr.  On failure,
- *              the value of *len_ptr is undefined.
+ * Purpose:	Tell the metadata cache how large the on disk image of the 
+ *		chunk proxy is, so it can load the image into a buffer for the 
+ *		deserialize call.  In this case, we simply look up the size in 
+ *		the user data, and return it in *image_len,
  *
- * Return:	Non-negative on success/Negative on failure
+ * Return:      Success:        SUCCEED
+ *              Failure:        FAIL
  *
- * Programmer:	John Mainzer
- *		5/13/04
+ * Programmer:  John Mainzer
+ *              7/28/14
  *
  *-------------------------------------------------------------------------
  */
 static herr_t
-H5O_size(const H5F_t H5_ATTR_UNUSED *f, const H5O_t *oh, size_t *size_ptr)
+H5O__cache_chk_get_load_size(const void *_udata, size_t *image_len)
 {
-    FUNC_ENTER_NOAPI_NOINIT_NOERR
+    const H5O_chk_cache_ud_t *udata = (const H5O_chk_cache_ud_t *)_udata;       /* User data for callback */
 
-    /* check args */
-    HDassert(oh);
-    HDassert(size_ptr);
+    FUNC_ENTER_STATIC_NOERR
 
-    /* Report the object header's prefix+first chunk length */
-    if(oh->chunk0_size)
-       *size_ptr = (size_t)H5O_SIZEOF_HDR(oh) + oh->chunk0_size;
-    else
-       *size_ptr = oh->chunk[0].size;
+    /* Check arguments */
+    HDassert(udata);
+    HDassert(udata->oh);
+    HDassert(image_len);
+
+    *image_len = udata->size;
 
     FUNC_LEAVE_NOAPI(SUCCEED)
-} /* H5O_size() */
+} /* end H5O__cache_chk_get_load_size() */
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5O_cache_chk_load
+ * Function:    H5O__cache_chk_deserialize
  *
- * Purpose:	Loads an object header continuation chunk from disk.
+ * Purpose:	Attempt to deserialize the object header continuation chunk
+ *		contained in the supplied buffer, load the data into an instance 
+ *		of H5O_chunk_proxy_t, and return a pointer to the new instance.
  *
- * Return:	Success:	Pointer to the new object header chunk proxy.
- *		Failure:	NULL
+ * Return:      Success:        Pointer to in core representation
+ *              Failure:        NULL
  *
- * Programmer:	Quincey Koziol
- *		koziol@hdfgroup.org
- *		Jul 12 2008
+ * Programmer:  John Mainzer
+ *              7/28/14
  *
  *-------------------------------------------------------------------------
  */
-static H5O_chunk_proxy_t *
-H5O_cache_chk_load(H5F_t *f, hid_t dxpl_id, haddr_t addr, void *_udata)
+static void *
+H5O__cache_chk_deserialize(const void *image, size_t len, void *_udata,
+    hbool_t *dirty)
 {
-    H5O_chunk_proxy_t	*chk_proxy = NULL;     /* Chunk proxy object */
-    H5O_chk_cache_ud_t *udata = (H5O_chk_cache_ud_t *)_udata;       /* User data for callback */
-    H5WB_t      *wb = NULL;             /* Wrapped buffer for prefix data */
-    uint8_t     chunk_buf[H5O_SPEC_READ_SIZE];       /* Buffer for speculative read */
-    uint8_t     *buf;                   /* Buffer to decode */
-    H5O_chunk_proxy_t	*ret_value;     /* Return value */
+    H5O_chunk_proxy_t  *chk_proxy = NULL;     /* Chunk proxy object */
+    H5O_chk_cache_ud_t *udata = (H5O_chk_cache_ud_t *)_udata;   /* User data for callback */
+    void *              ret_value;      /* Return value */
 
-    FUNC_ENTER_NOAPI_NOINIT
+    FUNC_ENTER_STATIC
 
     /* Check arguments */
-    HDassert(f);
-    HDassert(H5F_addr_defined(addr));
+    HDassert(image);
+    HDassert(len > 0);
     HDassert(udata);
     HDassert(udata->oh);
+    HDassert(dirty);
 
     /* Allocate space for the object header data structure */
-    if(NULL == (chk_proxy = H5FL_CALLOC(H5O_chunk_proxy_t)))
-	HGOTO_ERROR(H5E_OHDR, H5E_CANTALLOC, NULL, "memory allocation failed")
-
-    /* Wrap the local buffer for serialized header info */
-    if(NULL == (wb = H5WB_wrap(chunk_buf, sizeof(chunk_buf))))
-        HGOTO_ERROR(H5E_OHDR, H5E_CANTINIT, NULL, "can't wrap buffer")
-
-    /* Get a pointer to a buffer that's large enough for serialized header */
-    if(NULL == (buf = (uint8_t *)H5WB_actual(wb, udata->size)))
-        HGOTO_ERROR(H5E_OHDR, H5E_NOSPACE, NULL, "can't get actual buffer")
-
-    /* Read rest of the raw data */
-    if(H5F_block_read(f, H5FD_MEM_OHDR, addr, udata->size, dxpl_id, buf) < 0)
-        HGOTO_ERROR(H5E_OHDR, H5E_READERROR, NULL, "unable to read object header continuation chunk")
+    if(NULL == (chk_proxy = H5FL_CALLOC(H5O_chunk_proxy_t))) 
+        HGOTO_ERROR(H5E_OHDR, H5E_CANTALLOC, NULL, "memory allocation failed")
 
     /* Check if we are still decoding the object header */
     /* (as opposed to bringing a piece of it back from the file) */
@@ -719,7 +756,7 @@ H5O_cache_chk_load(H5F_t *f, hid_t dxpl_id, haddr_t addr, void *_udata)
         HDassert(udata->common.cont_msg_info);
 
         /* Parse the chunk */
-        if(H5O__chunk_deserialize(udata->oh, udata->common.addr, udata->size, buf, &(udata->common), &chk_proxy->cache_info.is_dirty) < 0)
+        if(H5O__chunk_deserialize(udata->oh, udata->common.addr, udata->size, (const uint8_t *)image, &(udata->common), dirty) < 0)
             HGOTO_ERROR(H5E_OHDR, H5E_CANTINIT, NULL, "can't deserialize object header chunk")
 
         /* Set the fields for the chunk proxy */
@@ -737,7 +774,7 @@ H5O_cache_chk_load(H5F_t *f, hid_t dxpl_id, haddr_t addr, void *_udata)
         /* Sanity check that the chunk representation we have in memory is 
          * the same as the one being brought in from disk.
          */
-        HDassert(0 == HDmemcmp(buf, chk_proxy->oh->chunk[chk_proxy->chunkno].image, chk_proxy->oh->chunk[chk_proxy->chunkno].size));
+        HDassert(0 == HDmemcmp(image, chk_proxy->oh->chunk[chk_proxy->chunkno].image, chk_proxy->oh->chunk[chk_proxy->chunkno].size));
     } /* end else */
 
     /* Increment reference count of object header */
@@ -748,213 +785,195 @@ H5O_cache_chk_load(H5F_t *f, hid_t dxpl_id, haddr_t addr, void *_udata)
     ret_value = chk_proxy;
 
 done:
-    /* Release resources */
-    if(wb && H5WB_unwrap(wb) < 0)
-        HDONE_ERROR(H5E_OHDR, H5E_CLOSEERROR, NULL, "can't close wrapped buffer")
-
-    /* Release the [possibly partially initialized] object header on errors */
-    if(!ret_value && chk_proxy)
-        if(H5O__chunk_proxy_dest(chk_proxy) < 0)
-	    HDONE_ERROR(H5E_OHDR, H5E_CANTRELEASE, NULL, "unable to destroy object header chunk proxy")
-
     FUNC_LEAVE_NOAPI(ret_value)
-} /* end H5O_cache_chk_load() */
+} /* end H5O__cache_chk_deserialize() */
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5O_cache_chk_flush
+ * Function:    H5O__cache_chk_image_len
  *
- * Purpose:	Flushes (and destroys) an object header continuation chunk.
+ * Purpose:	Return the on disk image size of a object header chunk to the 
+ *		metadata cache via the image_len.
  *
- * Return:	Non-negative on success/Negative on failure
+ * Return:      Success:        SUCCEED
+ *              Failure:        FAIL
  *
- * Programmer:	Quincey Koziol
- *		koziol@hdfgroup.org
- *		Jul 12 2008
+ * Programmer:  John Mainzer
+ *              7/28/14
  *
  *-------------------------------------------------------------------------
  */
 static herr_t
-H5O_cache_chk_flush(H5F_t *f, hid_t dxpl_id, hbool_t destroy, haddr_t addr,
-    H5O_chunk_proxy_t *chk_proxy, unsigned H5_ATTR_UNUSED * flags_ptr)
+H5O__cache_chk_image_len(const void *_thing, size_t *image_len,
+    hbool_t H5_ATTR_UNUSED *compressed_ptr, size_t H5_ATTR_UNUSED *compressed_image_len_ptr)
 {
-    herr_t ret_value = SUCCEED; /* Return value */
-
-    FUNC_ENTER_NOAPI_NOINIT
+    const H5O_chunk_proxy_t * chk_proxy = (const H5O_chunk_proxy_t *)_thing;    /* Chunk proxy to query */
 
-    /* flush */
-    if(chk_proxy->cache_info.is_dirty) {
-        /* Serialize messages for this chunk */
-        if(H5O__chunk_serialize(f, chk_proxy->oh, chk_proxy->chunkno) < 0)
-            HGOTO_ERROR(H5E_OHDR, H5E_CANTSERIALIZE, FAIL, "unable to serialize object header continuation chunk")
+    FUNC_ENTER_STATIC_NOERR
 
-        /* Write the chunk out */
-        HDassert(H5F_addr_defined(chk_proxy->oh->chunk[chk_proxy->chunkno].addr));
-        HDassert(H5F_addr_eq(addr, chk_proxy->oh->chunk[chk_proxy->chunkno].addr));
-        if(H5F_block_write(f, H5FD_MEM_OHDR, addr, chk_proxy->oh->chunk[chk_proxy->chunkno].size, dxpl_id, chk_proxy->oh->chunk[chk_proxy->chunkno].image) < 0)
-            HGOTO_ERROR(H5E_OHDR, H5E_WRITEERROR, FAIL, "unable to write object header continuation chunk to disk")
+    /* Check arguments */
+    HDassert(chk_proxy);
+    HDassert(chk_proxy->cache_info.magic == H5C__H5C_CACHE_ENTRY_T_MAGIC);
+    HDassert(chk_proxy->cache_info.type == H5AC_OHDR_CHK);
+    HDassert(chk_proxy->oh);
+    HDassert(image_len);
 
-        /* Mark object header as clean now */
-	chk_proxy->cache_info.is_dirty = FALSE;
-    } /* end if */
+    *image_len = chk_proxy->oh->chunk[chk_proxy->chunkno].size;
 
-    /* Destroy the object header, if requested */
-    if(destroy)
-        if(H5O_cache_chk_dest(f, chk_proxy) < 0)
-	    HGOTO_ERROR(H5E_OHDR, H5E_CANTFREE, FAIL, "unable to destroy object header continuation chunk data")
+    FUNC_LEAVE_NOAPI(SUCCEED)
+} /* end H5O__cache_chk_image_len() */
 
-done:
-    FUNC_LEAVE_NOAPI(ret_value)
-} /* end H5O_cache_chk_flush() */
+/************************************/
+/* no H5O_cache_chk_pre_serialize() */
+/************************************/
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5O_cache_chk_dest
+ * Function:    H5O__cache_chk_serialize
  *
- * Purpose:	Destroys an object header continuation chunk.
+ * Purpose:	Given a pointer to an instance of an object header chunk and an 
+ *		appropriately sized buffer, serialize the contents of the 
+ *		instance for writing to disk, and copy the serialized data 
+ *		into the buffer.
  *
- * Return:	Non-negative on success/Negative on failure
+ * Return:      Success:        SUCCEED
+ *              Failure:        FAIL
  *
- * Programmer:	Quincey Koziol
- *              koziol@hdfgroup.org
- *              July 12, 2008
+ * Programmer:  John Mainzer
+ *              7/28/14
  *
  *-------------------------------------------------------------------------
  */
 static herr_t
-H5O_cache_chk_dest(H5F_t *f, H5O_chunk_proxy_t *chk_proxy)
+H5O__cache_chk_serialize(const H5F_t *f, void *image, size_t len, void *_thing)
 {
-    herr_t      ret_value = SUCCEED;    /* Return value */
+    H5O_chunk_proxy_t * chk_proxy = (H5O_chunk_proxy_t *)_thing;        /* Object header chunk to serialize */
+    herr_t              ret_value = SUCCEED;    /* Return value */
 
-    FUNC_ENTER_NOAPI_NOINIT
+    FUNC_ENTER_STATIC
 
     /* Check arguments */
+    HDassert(f);
+    HDassert(image);
     HDassert(chk_proxy);
-    HDassert(chk_proxy->chunkno > 0);
-
-    /* Verify that node is clean */
-    HDassert(chk_proxy->cache_info.is_dirty == FALSE);
+    HDassert(chk_proxy->cache_info.magic == H5C__H5C_CACHE_ENTRY_T_MAGIC);
+    HDassert(chk_proxy->cache_info.type == H5AC_OHDR_CHK);
+    HDassert(chk_proxy->oh);
+    HDassert(chk_proxy->oh->chunk[chk_proxy->chunkno].size == len);
 
-    /* If we're going to free the space on disk, the address must be valid */
-    HDassert(!chk_proxy->cache_info.free_file_space_on_destroy || H5F_addr_defined(chk_proxy->cache_info.addr));
-
-    /* Check for releasing file space for object header */
-    if(chk_proxy->cache_info.free_file_space_on_destroy) {
-        /* Release the space on disk */
-        /* (XXX: Nasty usage of internal DXPL value! -QAK) */
-        if(H5MF_xfree(f, H5FD_MEM_OHDR, H5AC_dxpl_id, chk_proxy->oh->chunk[chk_proxy->chunkno].addr, (hsize_t)chk_proxy->oh->chunk[chk_proxy->chunkno].size) < 0)
-            HGOTO_ERROR(H5E_OHDR, H5E_CANTFREE, FAIL, "unable to free object header continuation chunk")
-    } /* end if */
+    /* Serialize messages for this chunk */
+    if(H5O__chunk_serialize(f, chk_proxy->oh, chk_proxy->chunkno) < 0)
+        HGOTO_ERROR(H5E_OHDR, H5E_CANTSERIALIZE, FAIL, "unable to serialize object header continuation chunk")
 
-    /* Destroy object header chunk proxy */
-    if(H5O__chunk_proxy_dest(chk_proxy) < 0)
-        HGOTO_ERROR(H5E_OHDR, H5E_CANTRELEASE, FAIL, "unable to destroy object header chunk proxy")
+    /* copy the chunk into the image -- this is potentially expensive.
+     * Can we rework things so that the chunk and the cache share a buffer?
+     */
+    HDmemcpy(image, chk_proxy->oh->chunk[chk_proxy->chunkno].image, len);
 
 done:
     FUNC_LEAVE_NOAPI(ret_value)
-} /* end H5O_cache_chk_dest() */
+} /* end H5O__cache_chk_serialize() */
+
+/**************************************/
+/* no H5O_cache_chk_notify() function */
+/**************************************/
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5O_cache_chk_clear
- *
- * Purpose:	Mark a object header continuation chunk in memory as non-dirty.
- *
- * Return:	Non-negative on success/Negative on failure
- *
- * Programmer:	Quincey Koziol
- *              koziol@hdfgroup.org
- *              July 12, 2008
+ * Function:    H5O__cache_chk_free_icr
  *
- * Changes:     In the parallel case, there is the possibility that the
- *              the object header chunk may be flushed by different
- *              processes over the life of the computation.  Thus we must
- *              ensure that the chunk image is up to date before we mark its
- *              messages clean -- as otherwise we may overwrite valid
- *              data with a blank section of a chunk image.
+ * Purpose:	Free the in core memory associated with the supplied object
+ *		header continuation chunk.
  *
- *              To deal with this, I have added code to call
- *              H5O_chunk_serialize() for this chunk before we
- *              mark all messages as clean if we are not destroying the
- *              chunk.
+ * Note:	The metadata cache sets the object's cache_info.magic to
+ *		H5C__H5C_CACHE_ENTRY_T_BAD_MAGIC before calling a free_icr
+ *		callback (checked in assert).
  *
- *              Do this in the parallel case only, as the problem
- *              can only occur in this context.
+ * Return:      Success:        SUCCEED
+ *              Failure:        FAIL
  *
- *              Note that at present at least, it seems that this fix
- *              is not necessary, as we don't seem to be able to
- *              generate a dirty chunk without creating a dirty object
- *              header.  However, the object header code will be changing
- *              a lot in the near future, so I'll leave this fix in
- *              for now, unless Quincey requests otherwise.
- *
- *                                              JRM -- 10/12/10
+ * Programmer:  John Mainzer
+ *              7/28/14
  *
  *-------------------------------------------------------------------------
  */
 static herr_t
-H5O_cache_chk_clear(H5F_t *f, H5O_chunk_proxy_t *chk_proxy, hbool_t destroy)
+H5O__cache_chk_free_icr(void *_thing)
 {
-    unsigned	u;      /* Local index variable */
-    herr_t ret_value = SUCCEED;
+    H5O_chunk_proxy_t * chk_proxy = (H5O_chunk_proxy_t *)_thing;        /* Object header chunk proxy to release */
+    herr_t              ret_value = SUCCEED;    /* Return value */
 
-    FUNC_ENTER_NOAPI_NOINIT
+    FUNC_ENTER_STATIC
 
     /* Check arguments */
     HDassert(chk_proxy);
+    HDassert(chk_proxy->cache_info.magic == H5C__H5C_CACHE_ENTRY_T_BAD_MAGIC);
+    HDassert(chk_proxy->cache_info.type == H5AC_OHDR_CHK);
 
-#ifdef H5_HAVE_PARALLEL
-    if((chk_proxy->oh->cache_info.is_dirty) && (!destroy))
-        if(H5O__chunk_serialize(f, chk_proxy->oh, chk_proxy->chunkno) < 0)
-            HGOTO_ERROR(H5E_OHDR, H5E_CANTSERIALIZE, FAIL, "unable to serialize object header chunk")
-#endif /* H5_HAVE_PARALLEL */
-
-    /* Mark messages in chunk as clean */
-    for(u = 0; u < chk_proxy->oh->nmesgs; u++)
-        if(chk_proxy->oh->mesg[u].chunkno == chk_proxy->chunkno)
-            chk_proxy->oh->mesg[u].dirty = FALSE;
-
-    /* Mark as clean */
-    chk_proxy->cache_info.is_dirty = FALSE;
-
-    if(destroy)
-        if(H5O_cache_chk_dest(f, chk_proxy) < 0)
-            HGOTO_ERROR(H5E_OHDR, H5E_CANTFREE, FAIL, "unable to destroy object header continuation chunk data")
+    /* Destroy object header chunk proxy */
+    if(H5O__chunk_proxy_dest(chk_proxy) < 0)
+        HGOTO_ERROR(H5E_OHDR, H5E_CANTRELEASE, FAIL, "unable to destroy object header chunk proxy")
 
 done:
     FUNC_LEAVE_NOAPI(ret_value)
-} /* end H5O_cache_chk_clear() */
+} /* end H5O__cache_chk_free_icr() */
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5O_cache_chk_size
+ * Function:    H5O__cache_chk_clear
  *
- * Purpose:	Compute the size in bytes of the specified instance of
- *              an object header continuation chunk on disk, and return it in
- *              *len_ptr.  On failure, the value of *len_ptr is undefined.
+ * Purpose: 	Clear all dirty bits associated with this cache entry.
  *
- * Return:	Non-negative on success/Negative on failure
+ *		This is ncessary as the object header cache client maintains 
+ *		its own dirty bits on individual messages.  These dirty bits 
+ *		used to be cleared by the old V2 metadata cache flush callback,
+ *		but now the metadata cache must clear them explicitly, as 
+ *		the serialize callback does not imply that the data has been
+ *		written to disk.
  *
- * Programmer:	Quincey Koziol
- *              koziol@hdfgroup.org
- *              July 12, 2008
+ *		This callback is also necessary for the parallel case.
+ *
+ * Return:      Success:        SUCCEED
+ *              Failure:        FAIL
+ *
+ * Programmer:  John Mainzer
+ *              9/22/14
  *
  *-------------------------------------------------------------------------
  */
 static herr_t
-H5O_cache_chk_size(const H5F_t H5_ATTR_UNUSED *f, const H5O_chunk_proxy_t *chk_proxy, size_t *size_ptr)
-{
-    FUNC_ENTER_NOAPI_NOINIT_NOERR
+H5O__cache_chk_clear(const H5F_t *f, void *_thing, hbool_t about_to_destroy)
+{ 
+    H5O_chunk_proxy_t  *chk_proxy = (H5O_chunk_proxy_t *)_thing;        /* Object header chunk to reset */
+    H5O_t              *oh;                     /* Object header for chunk */
+    unsigned            u;                      /* Local index variable */
+    herr_t              ret_value = SUCCEED;    /* Return value */
 
-    /* check args */
+    FUNC_ENTER_STATIC
+
+    /* Check arguments */
     HDassert(chk_proxy);
-    HDassert(size_ptr);
+    HDassert(chk_proxy->cache_info.magic == H5C__H5C_CACHE_ENTRY_T_MAGIC);
+    HDassert(chk_proxy->cache_info.type == H5AC_OHDR_CHK);
+    oh = chk_proxy->oh;
+    HDassert(oh);
+    HDassert(oh->cache_info.magic == H5C__H5C_CACHE_ENTRY_T_MAGIC);
+    HDassert(oh->cache_info.type == H5AC_OHDR);
 
-    /* Report the object header continuation chunk's length */
-    *size_ptr = chk_proxy->oh->chunk[chk_proxy->chunkno].size;
+#ifdef H5_HAVE_PARALLEL
+    if((chk_proxy->oh->cache_info.is_dirty) && (!about_to_destroy))
+        if(H5O__chunk_serialize(f, chk_proxy->oh, chk_proxy->chunkno) < 0)
+            HGOTO_ERROR(H5E_OHDR, H5E_CANTSERIALIZE, FAIL, "unable to serialize object header chunk")
+#endif /* H5_HAVE_PARALLEL */
 
-    FUNC_LEAVE_NOAPI(SUCCEED)
-} /* H5O_cache_chk_size() */
+    /* Mark messages in chunk as clean */
+    for(u = 0; u < chk_proxy->oh->nmesgs; u++)
+        if(chk_proxy->oh->mesg[u].chunkno == chk_proxy->chunkno)
+            chk_proxy->oh->mesg[u].dirty = FALSE;
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5O__cache_chk_clear() */
 
 
 /*-------------------------------------------------------------------------
@@ -1024,7 +1043,7 @@ static herr_t
 H5O__chunk_deserialize(H5O_t *oh, haddr_t addr, size_t len, const uint8_t *image,
     H5O_common_cache_ud_t *udata, hbool_t *dirty)
 {
-    const uint8_t *p;           /* Pointer into buffer to decode */
+    const uint8_t *chunk_image; /* Pointer into buffer to decode */
     uint8_t *eom_ptr;           /* Pointer to end of messages for a chunk */
     size_t curmesg;             /* Current message being decoded in object header */
     unsigned merged_null_msgs = 0;  /* Number of null messages merged together */
@@ -1073,18 +1092,18 @@ H5O__chunk_deserialize(H5O_t *oh, haddr_t addr, size_t len, const uint8_t *image
     HDmemcpy(oh->chunk[chunkno].image, image, oh->chunk[chunkno].size);
 
     /* Point into chunk image to decode */
-    p = oh->chunk[chunkno].image;
+    chunk_image = oh->chunk[chunkno].image;
 
     /* Handle chunk 0 as special case */
     if(chunkno == 0)
         /* Skip over [already decoded] prefix */
-        p += (size_t)(H5O_SIZEOF_HDR(oh) - H5O_SIZEOF_CHKSUM_OH(oh));
+        chunk_image += (size_t)(H5O_SIZEOF_HDR(oh) - H5O_SIZEOF_CHKSUM_OH(oh));
     /* Check for magic # on chunks > 0 in later versions of the format */
     else if(chunkno > 0 && oh->version > H5O_VERSION_1) {
         /* Magic number */
-        if(HDmemcmp(p, H5O_CHK_MAGIC, (size_t)H5_SIZEOF_MAGIC))
+        if(HDmemcmp(chunk_image, H5O_CHK_MAGIC, (size_t)H5_SIZEOF_MAGIC))
             HGOTO_ERROR(H5E_OHDR, H5E_CANTLOAD, FAIL, "wrong object header chunk signature")
-        p += H5_SIZEOF_MAGIC;
+        chunk_image += H5_SIZEOF_MAGIC;
     } /* end if */
 
     /* Save # of messages already inspected */
@@ -1095,7 +1114,7 @@ H5O__chunk_deserialize(H5O_t *oh, haddr_t addr, size_t len, const uint8_t *image
 #ifndef NDEBUG
     nullcnt = 0;
 #endif /* NDEBUG */
-    while(p < eom_ptr) {
+    while(chunk_image < eom_ptr) {
         size_t mesgno;          /* Current message to operate on */
         size_t mesg_size;       /* Size of message read in */
         unsigned id;            /* ID (type) of current message */
@@ -1106,20 +1125,20 @@ H5O__chunk_deserialize(H5O_t *oh, haddr_t addr, size_t len, const uint8_t *image
 
         /* Version # */
         if(oh->version == H5O_VERSION_1)
-            UINT16DECODE(p, id)
+            UINT16DECODE(chunk_image, id)
         else
-            id = *p++;
+            id = *chunk_image++;
 
         /* Check for unknown message ID getting encoded in file */
         if(id == H5O_UNKNOWN_ID)
             HGOTO_ERROR(H5E_OHDR, H5E_CANTLOAD, FAIL, "'unknown' message ID encoded in file?!?")
 
         /* Message size */
-        UINT16DECODE(p, mesg_size);
+        UINT16DECODE(chunk_image, mesg_size);
         HDassert(mesg_size == H5O_ALIGN_OH(oh, mesg_size));
 
         /* Message flags */
-        flags = *p++;
+        flags = *chunk_image++;
         if(flags & ~H5O_MSG_FLAG_BITS)
             HGOTO_ERROR(H5E_OHDR, H5E_CANTLOAD, FAIL, "unknown flag for message")
         if((flags & H5O_MSG_FLAG_SHARED) && (flags & H5O_MSG_FLAG_DONTSHARE))
@@ -1131,17 +1150,17 @@ H5O__chunk_deserialize(H5O_t *oh, haddr_t addr, size_t len, const uint8_t *image
 
         /* Reserved bytes/creation index */
         if(oh->version == H5O_VERSION_1)
-            p += 3; /*reserved*/
+            chunk_image += 3; /*reserved*/
         else {
             /* Only decode creation index if they are being tracked */
             if(oh->flags & H5O_HDR_ATTR_CRT_ORDER_TRACKED)
-                UINT16DECODE(p, crt_idx);
+                UINT16DECODE(chunk_image, crt_idx);
         } /* end else */
 
         /* Try to detect invalidly formatted object header message that
          *  extends past end of chunk.
          */
-        if(p + mesg_size > eom_ptr)
+        if(chunk_image + mesg_size > eom_ptr)
             HGOTO_ERROR(H5E_OHDR, H5E_CANTINIT, FAIL, "corrupt object header")
 
 #ifndef NDEBUG
@@ -1177,7 +1196,7 @@ H5O__chunk_deserialize(H5O_t *oh, haddr_t addr, size_t len, const uint8_t *image
             oh->mesg[mesgno].flags = flags;
             oh->mesg[mesgno].crt_idx = crt_idx;
             oh->mesg[mesgno].native = NULL;
-            oh->mesg[mesgno].raw = (uint8_t *)p;        /* Casting away const OK - QAK */
+            oh->mesg[mesgno].raw = (uint8_t *)chunk_image;        /* Casting away const OK - QAK */
             oh->mesg[mesgno].raw_size = mesg_size;
             oh->mesg[mesgno].chunkno = chunkno;
 
@@ -1233,10 +1252,10 @@ H5O__chunk_deserialize(H5O_t *oh, haddr_t addr, size_t len, const uint8_t *image
         } /* end else */
 
         /* Advance decode pointer past message */
-        p += mesg_size;
+        chunk_image += mesg_size;
 
         /* Check for 'gap' at end of chunk */
-        if((eom_ptr - p) > 0 && (eom_ptr - p) < H5O_SIZEOF_MSGHDR_OH(oh)) {
+        if((eom_ptr - chunk_image) > 0 && (eom_ptr - chunk_image) < H5O_SIZEOF_MSGHDR_OH(oh)) {
             /* Gaps can only occur in later versions of the format */
             HDassert(oh->version > H5O_VERSION_1);
 
@@ -1244,10 +1263,10 @@ H5O__chunk_deserialize(H5O_t *oh, haddr_t addr, size_t len, const uint8_t *image
             HDassert(nullcnt == 0);
 
             /* Set gap information for chunk */
-            oh->chunk[chunkno].gap = (size_t)(eom_ptr - p);
+            oh->chunk[chunkno].gap = (size_t)(eom_ptr - chunk_image);
 
             /* Increment location in chunk */
-            p += oh->chunk[chunkno].gap;
+            chunk_image += oh->chunk[chunkno].gap;
         } /* end if */
     } /* end while */
 
@@ -1257,7 +1276,7 @@ H5O__chunk_deserialize(H5O_t *oh, haddr_t addr, size_t len, const uint8_t *image
         uint32_t computed_chksum;   /* Checksum computed in memory */
 
         /* Metadata checksum */
-        UINT32DECODE(p, stored_chksum);
+        UINT32DECODE(chunk_image, stored_chksum);
 
         /* Compute checksum on chunk */
         computed_chksum = H5_checksum_metadata(oh->chunk[chunkno].image, (oh->chunk[chunkno].size - H5O_SIZEOF_CHKSUM), 0);
@@ -1268,7 +1287,7 @@ H5O__chunk_deserialize(H5O_t *oh, haddr_t addr, size_t len, const uint8_t *image
     } /* end if */
 
     /* Sanity check */
-    HDassert(p == oh->chunk[chunkno].image + oh->chunk[chunkno].size);
+    HDassert(chunk_image == oh->chunk[chunkno].image + oh->chunk[chunkno].size);
 
     /* Do some inspection/interpretation of new messages from this chunk */
     /* (detect continuation messages, ref. count messages, etc.) */
@@ -1390,7 +1409,7 @@ H5O__chunk_serialize(const H5F_t *f, H5O_t *oh, unsigned chunkno)
     /* Extra work, for later versions of the format */
     if(oh->version > H5O_VERSION_1) {
         uint32_t metadata_chksum;   /* Computed metadata checksum value */
-        uint8_t	*p;                 /* Pointer into object header chunk */
+        uint8_t	*chunk_image;       /* Pointer into object header chunk */
 
         /* Check for gap in chunk & zero it out */
         if(oh->chunk[chunkno].gap)
@@ -1401,8 +1420,8 @@ H5O__chunk_serialize(const H5F_t *f, H5O_t *oh, unsigned chunkno)
         metadata_chksum = H5_checksum_metadata(oh->chunk[chunkno].image, (oh->chunk[chunkno].size - H5O_SIZEOF_CHKSUM), 0);
 
         /* Metadata checksum */
-        p = oh->chunk[chunkno].image + (oh->chunk[chunkno].size - H5O_SIZEOF_CHKSUM);
-        UINT32ENCODE(p, metadata_chksum);
+        chunk_image = oh->chunk[chunkno].image + (oh->chunk[chunkno].size - H5O_SIZEOF_CHKSUM);
+        UINT32ENCODE(chunk_image, metadata_chksum);
     } /* end if */
 
 done:
@@ -1443,5 +1462,5 @@ H5O__chunk_proxy_dest(H5O_chunk_proxy_t *chk_proxy)
 
 done:
     FUNC_LEAVE_NOAPI(ret_value)
-} /* H5O_chunk_proxy_dest() */
+} /* H5O__chunk_proxy_dest() */
 
diff --git a/src/H5Ochunk.c b/src/H5Ochunk.c
index 41d3f66..bb82ad1 100644
--- a/src/H5Ochunk.c
+++ b/src/H5Ochunk.c
@@ -184,7 +184,7 @@ H5O_chunk_protect(H5F_t *f, hid_t dxpl_id, H5O_t *oh, unsigned idx)
         chk_udata.size = oh->chunk[idx].size;
 
         /* Get the chunk proxy */
-        if(NULL == (chk_proxy = (H5O_chunk_proxy_t *)H5AC_protect(f, dxpl_id, H5AC_OHDR_CHK, oh->chunk[idx].addr, &chk_udata, H5AC_WRITE)))
+        if(NULL == (chk_proxy = (H5O_chunk_proxy_t *)H5AC_protect(f, dxpl_id, H5AC_OHDR_CHK, oh->chunk[idx].addr, &chk_udata, H5AC__NO_FLAGS_SET)))
             HGOTO_ERROR(H5E_OHDR, H5E_CANTPROTECT, NULL, "unable to load object header chunk")
 
         /* Sanity check */
@@ -337,7 +337,7 @@ H5O_chunk_update_idx(H5F_t *f, hid_t dxpl_id, H5O_t *oh, unsigned idx)
     chk_udata.size = oh->chunk[idx].size;
 
     /* Get the chunk proxy */
-    if(NULL == (chk_proxy = (H5O_chunk_proxy_t *)H5AC_protect(f, dxpl_id, H5AC_OHDR_CHK, oh->chunk[idx].addr, &chk_udata, H5AC_WRITE)))
+    if(NULL == (chk_proxy = (H5O_chunk_proxy_t *)H5AC_protect(f, dxpl_id, H5AC_OHDR_CHK, oh->chunk[idx].addr, &chk_udata, H5AC__NO_FLAGS_SET)))
         HGOTO_ERROR(H5E_OHDR, H5E_CANTPROTECT, FAIL, "unable to load object header chunk")
 
     /* Update index for chunk proxy in cache */
@@ -389,7 +389,7 @@ H5O_chunk_delete(H5F_t *f, hid_t dxpl_id, H5O_t *oh, unsigned idx)
     chk_udata.size = oh->chunk[idx].size;
 
     /* Get the chunk proxy */
-    if(NULL == (chk_proxy = (H5O_chunk_proxy_t *)H5AC_protect(f, dxpl_id, H5AC_OHDR_CHK, oh->chunk[idx].addr, &chk_udata, H5AC_WRITE)))
+    if(NULL == (chk_proxy = (H5O_chunk_proxy_t *)H5AC_protect(f, dxpl_id, H5AC_OHDR_CHK, oh->chunk[idx].addr, &chk_udata, H5AC__NO_FLAGS_SET)))
         HGOTO_ERROR(H5E_OHDR, H5E_CANTPROTECT, FAIL, "unable to load object header chunk")
 
     /* Sanity check */
diff --git a/src/H5Ocopy.c b/src/H5Ocopy.c
index afd8e94..66322da 100644
--- a/src/H5Ocopy.c
+++ b/src/H5Ocopy.c
@@ -379,7 +379,7 @@ H5O_copy_header_real(const H5O_loc_t *oloc_src, H5O_loc_t *oloc_dst /*out*/,
     }
 
     /* Get source object header */
-    if(NULL == (oh_src = H5O_protect(oloc_src, dxpl_id, H5AC_READ)))
+    if(NULL == (oh_src = H5O_protect(oloc_src, dxpl_id, H5AC__READ_ONLY_FLAG)))
         HGOTO_ERROR(H5E_OHDR, H5E_CANTPROTECT, FAIL, "unable to load object header")
 
     /* Retrieve user data for particular type of object to copy */
diff --git a/src/H5Odbg.c b/src/H5Odbg.c
index 0531a90..0388cd5 100644
--- a/src/H5Odbg.c
+++ b/src/H5Odbg.c
@@ -566,7 +566,7 @@ H5O_debug(H5F_t *f, hid_t dxpl_id, haddr_t addr, FILE *stream, int indent, int f
     loc.addr = addr;
     loc.holding_file = FALSE;
 
-    if(NULL == (oh = H5O_protect(&loc, dxpl_id, H5AC_READ)))
+    if(NULL == (oh = H5O_protect(&loc, dxpl_id, H5AC__READ_ONLY_FLAG)))
 	HGOTO_ERROR(H5E_OHDR, H5E_CANTPROTECT, FAIL, "unable to load object header")
 
     /* debug */
diff --git a/src/H5Oefl.c b/src/H5Oefl.c
index e37e9b7..a7ce31a 100644
--- a/src/H5Oefl.c
+++ b/src/H5Oefl.c
@@ -128,7 +128,7 @@ H5O_efl_decode(H5F_t *f, hid_t dxpl_id, H5O_t H5_ATTR_UNUSED *open_oh,
 #ifndef NDEBUG
     HDassert(H5F_addr_defined(mesg->heap_addr));
 
-    if(NULL == (heap = H5HL_protect(f, dxpl_id, mesg->heap_addr, H5AC_READ)))
+    if(NULL == (heap = H5HL_protect(f, dxpl_id, mesg->heap_addr, H5AC__READ_ONLY_FLAG)))
         HGOTO_ERROR(H5E_SYM, H5E_NOTFOUND, NULL, "unable to read protect link value")
 
     s = (const char *)H5HL_offset_into(heap, 0);
@@ -145,7 +145,7 @@ H5O_efl_decode(H5F_t *f, hid_t dxpl_id, H5O_t H5_ATTR_UNUSED *open_oh,
     if(NULL == mesg->slot)
 	HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, NULL, "memory allocation failed")
 
-    if(NULL == (heap = H5HL_protect(f, dxpl_id, mesg->heap_addr, H5AC_READ)))
+    if(NULL == (heap = H5HL_protect(f, dxpl_id, mesg->heap_addr, H5AC__READ_ONLY_FLAG)))
         HGOTO_ERROR(H5E_SYM, H5E_NOTFOUND, NULL, "unable to read protect link value")
     for(u = 0; u < mesg->nused; u++) {
 	/* Name */
@@ -487,7 +487,7 @@ H5O_efl_copy_file(H5F_t H5_ATTR_UNUSED *file_src, void *mesg_src, H5F_t *file_ds
         HGOTO_ERROR(H5E_EFL, H5E_CANTINIT, NULL, "can't create heap")
 
     /* Pin the heap down in memory */
-    if(NULL == (heap = H5HL_protect(file_dst, dxpl_id, efl_dst->heap_addr, H5AC_WRITE)))
+    if(NULL == (heap = H5HL_protect(file_dst, dxpl_id, efl_dst->heap_addr, H5AC__NO_FLAGS_SET)))
         HGOTO_ERROR(H5E_EFL, H5E_PROTECT, NULL, "unable to protect EFL file name heap")
 
     /* Insert "empty" name first */
diff --git a/src/H5Omessage.c b/src/H5Omessage.c
index d361194..c2756ea 100644
--- a/src/H5Omessage.c
+++ b/src/H5Omessage.c
@@ -476,7 +476,7 @@ H5O_msg_read(const H5O_loc_t *loc, unsigned type_id, void *mesg,
     HDassert(type_id < NELMTS(H5O_msg_class_g));
 
     /* Get the object header */
-    if(NULL == (oh = H5O_protect(loc, dxpl_id, H5AC_READ)))
+    if(NULL == (oh = H5O_protect(loc, dxpl_id, H5AC__READ_ONLY_FLAG)))
 	HGOTO_ERROR(H5E_OHDR, H5E_CANTPROTECT, NULL, "unable to protect object header")
 
     /* Call the "real" read routine */
@@ -802,7 +802,7 @@ H5O_msg_count(const H5O_loc_t *loc, unsigned type_id, hid_t dxpl_id)
     HDassert(type);
 
     /* Load the object header */
-    if(NULL == (oh = H5O_protect(loc, dxpl_id, H5AC_READ)))
+    if(NULL == (oh = H5O_protect(loc, dxpl_id, H5AC__READ_ONLY_FLAG)))
 	HGOTO_ERROR(H5E_OHDR, H5E_CANTPROTECT, FAIL, "unable to protect object header")
 
     /* Count the messages of the correct type */
@@ -884,7 +884,7 @@ H5O_msg_exists(const H5O_loc_t *loc, unsigned type_id, hid_t dxpl_id)
     HDassert(type_id < NELMTS(H5O_msg_class_g));
 
     /* Load the object header */
-    if(NULL == (oh = H5O_protect(loc, dxpl_id, H5AC_READ)))
+    if(NULL == (oh = H5O_protect(loc, dxpl_id, H5AC__READ_ONLY_FLAG)))
 	HGOTO_ERROR(H5E_OHDR, H5E_CANTPROTECT, FAIL, "unable to protect object header")
 
     /* Call the "real" exists routine */
@@ -1224,7 +1224,7 @@ H5O_msg_iterate(const H5O_loc_t *loc, unsigned type_id,
     HDassert(op);
 
     /* Protect the object header to iterate over */
-    if(NULL == (oh = H5O_protect(loc, dxpl_id, H5AC_READ)))
+    if(NULL == (oh = H5O_protect(loc, dxpl_id, H5AC__READ_ONLY_FLAG)))
 	HGOTO_ERROR(H5E_OHDR, H5E_CANTPROTECT, FAIL, "unable to protect object header")
 
     /* Call the "real" iterate routine */
@@ -2289,7 +2289,7 @@ H5O_msg_get_chunkno(const H5O_loc_t *loc, unsigned type_id, hid_t dxpl_id)
     HDassert(type);
 
     /* Get the object header */
-    if(NULL == (oh = H5O_protect(loc, dxpl_id, H5AC_READ)))
+    if(NULL == (oh = H5O_protect(loc, dxpl_id, H5AC__READ_ONLY_FLAG)))
 	HGOTO_ERROR(H5E_OHDR, H5E_CANTPROTECT, FAIL, "unable to protect object header")
 
     /* Locate message of correct type */
@@ -2344,7 +2344,7 @@ H5O_msg_lock(const H5O_loc_t *loc, unsigned type_id, hid_t dxpl_id)
     HDassert(type);
 
     /* Get the object header */
-    if(NULL == (oh = H5O_protect(loc, dxpl_id, H5AC_READ)))
+    if(NULL == (oh = H5O_protect(loc, dxpl_id, H5AC__READ_ONLY_FLAG)))
 	HGOTO_ERROR(H5E_OHDR, H5E_CANTPROTECT, FAIL, "unable to protect object header")
 
     /* Locate message of correct type */
@@ -2402,7 +2402,7 @@ H5O_msg_unlock(const H5O_loc_t *loc, unsigned type_id, hid_t dxpl_id)
     HDassert(type);
 
     /* Get the object header */
-    if(NULL == (oh = H5O_protect(loc, dxpl_id, H5AC_READ)))
+    if(NULL == (oh = H5O_protect(loc, dxpl_id, H5AC__READ_ONLY_FLAG)))
 	HGOTO_ERROR(H5E_OHDR, H5E_CANTPROTECT, FAIL, "unable to protect object header")
 
     /* Locate message of correct type */
diff --git a/src/H5Oprivate.h b/src/H5Oprivate.h
index cc262a0..92d0107 100644
--- a/src/H5Oprivate.h
+++ b/src/H5Oprivate.h
@@ -564,6 +564,8 @@ typedef struct H5O_btreek_t {
  * (Data structure in memory)
  */
 typedef struct H5O_drvinfo_t {
+/* Information for H5AC cache functions, _must_ be first field in structure */
+    H5AC_info_t         cache_info;
     char                name[9];                /* Driver name */
     size_t		len;                    /* Length of encoded buffer */
     uint8_t            *buf;                    /* Buffer for encoded info */
@@ -659,7 +661,7 @@ H5_DLL herr_t H5O_create(H5F_t *f, hid_t dxpl_id, size_t size_hint,
 H5_DLL herr_t H5O_open(H5O_loc_t *loc);
 H5_DLL herr_t H5O_close(H5O_loc_t *loc);
 H5_DLL int H5O_link(const H5O_loc_t *loc, int adjust, hid_t dxpl_id);
-H5_DLL H5O_t *H5O_protect(const H5O_loc_t *loc, hid_t dxpl_id, H5AC_protect_t prot);
+H5_DLL H5O_t *H5O_protect(const H5O_loc_t *loc, hid_t dxpl_id, unsigned prot_flags);
 H5_DLL H5O_t *H5O_pin(const H5O_loc_t *loc, hid_t dxpl_id);
 H5_DLL herr_t H5O_unpin(H5O_t *oh);
 H5_DLL herr_t H5O_dec_rc_by_loc(const H5O_loc_t *loc, hid_t dxpl_id);
diff --git a/src/H5Otest.c b/src/H5Otest.c
index d1627ef..e7312ee 100644
--- a/src/H5Otest.c
+++ b/src/H5Otest.c
@@ -108,7 +108,7 @@ H5O_is_attr_dense_test(hid_t oid)
         HGOTO_ERROR(H5E_SYM, H5E_NOTFOUND, FAIL, "object not found")
 
     /* Get the object header */
-    if(NULL == (oh = H5O_protect(loc, H5AC_ind_dxpl_id, H5AC_READ)))
+    if(NULL == (oh = H5O_protect(loc, H5AC_ind_dxpl_id, H5AC__READ_ONLY_FLAG)))
 	HGOTO_ERROR(H5E_OHDR, H5E_CANTPROTECT, FAIL, "unable to load object header")
 
     /* Check for attribute info stored */
@@ -173,7 +173,7 @@ H5O_is_attr_empty_test(hid_t oid)
         HGOTO_ERROR(H5E_SYM, H5E_NOTFOUND, FAIL, "object not found")
 
     /* Get the object header */
-    if(NULL == (oh = H5O_protect(loc, H5AC_ind_dxpl_id, H5AC_READ)))
+    if(NULL == (oh = H5O_protect(loc, H5AC_ind_dxpl_id, H5AC__READ_ONLY_FLAG)))
 	HGOTO_ERROR(H5E_OHDR, H5E_CANTPROTECT, FAIL, "unable to load object header")
 
     /* Check for attribute info stored */
@@ -266,7 +266,7 @@ H5O_num_attrs_test(hid_t oid, hsize_t *nattrs)
         HGOTO_ERROR(H5E_SYM, H5E_NOTFOUND, FAIL, "object not found")
 
     /* Get the object header */
-    if(NULL == (oh = H5O_protect(loc, H5AC_ind_dxpl_id, H5AC_READ)))
+    if(NULL == (oh = H5O_protect(loc, H5AC_ind_dxpl_id, H5AC__READ_ONLY_FLAG)))
 	HGOTO_ERROR(H5E_OHDR, H5E_CANTPROTECT, FAIL, "unable to load object header")
 
     /* Check for attribute info stored */
@@ -361,7 +361,7 @@ H5O_attr_dense_info_test(hid_t oid, hsize_t *name_count, hsize_t *corder_count)
     H5_BEGIN_TAG(H5AC_ind_dxpl_id, loc->addr, FAIL);
 
     /* Get the object header */
-    if(NULL == (oh = H5O_protect(loc, H5AC_ind_dxpl_id, H5AC_READ)))
+    if(NULL == (oh = H5O_protect(loc, H5AC_ind_dxpl_id, H5AC__READ_ONLY_FLAG)))
 	HGOTO_ERROR_TAG(H5E_OHDR, H5E_CANTPROTECT, FAIL, "unable to load object header")
 
     /* Check for attribute info stored */
@@ -452,7 +452,7 @@ H5O_check_msg_marked_test(hid_t oid, hbool_t flag_val)
         HGOTO_ERROR(H5E_SYM, H5E_NOTFOUND, FAIL, "object not found")
 
     /* Get the object header */
-    if(NULL == (oh = H5O_protect(loc, H5AC_ind_dxpl_id, H5AC_READ)))
+    if(NULL == (oh = H5O_protect(loc, H5AC_ind_dxpl_id, H5AC__READ_ONLY_FLAG)))
 	HGOTO_ERROR(H5E_OHDR, H5E_CANTPROTECT, FAIL, "unable to load object header")
 
     /* Locate "unknown" message  */
@@ -511,7 +511,7 @@ H5O_expunge_chunks_test(const H5O_loc_t *loc, hid_t dxpl_id)
     FUNC_ENTER_NOAPI(FAIL)
 
     /* Get the object header */
-    if(NULL == (oh = H5O_protect(loc, dxpl_id, H5AC_WRITE)))
+    if(NULL == (oh = H5O_protect(loc, dxpl_id, H5AC__NO_FLAGS_SET)))
 	HGOTO_ERROR(H5E_OHDR, H5E_CANTPROTECT, FAIL, "unable to protect object header")
 
     /* Safety check */
@@ -571,7 +571,7 @@ H5O_get_rc(const H5O_loc_t *loc, hid_t dxpl_id, unsigned *rc)
     HDassert(rc);
 
     /* Get the object header */
-    if(NULL == (oh = H5O_protect(loc, dxpl_id, H5AC_READ)))
+    if(NULL == (oh = H5O_protect(loc, dxpl_id, H5AC__READ_ONLY_FLAG)))
 	HGOTO_ERROR(H5E_OHDR, H5E_CANTPROTECT, FAIL, "unable to protect object header")
 
     /* Save the refcount for the object header */
diff --git a/src/H5SM.c b/src/H5SM.c
index abdb109..1d391f1 100644
--- a/src/H5SM.c
+++ b/src/H5SM.c
@@ -358,7 +358,7 @@ H5SM_type_shared(H5F_t *f, unsigned type_id, hid_t dxpl_id)
         /* Set up user data for callback */
         cache_udata.f = f;
 
-        if(NULL == (table = (H5SM_master_table_t *)H5AC_protect(f, dxpl_id, H5AC_SOHM_TABLE, H5F_SOHM_ADDR(f), &cache_udata, H5AC_READ)))
+        if(NULL == (table = (H5SM_master_table_t *)H5AC_protect(f, dxpl_id, H5AC_SOHM_TABLE, H5F_SOHM_ADDR(f), &cache_udata, H5AC__READ_ONLY_FLAG)))
             HGOTO_ERROR(H5E_SOHM, H5E_CANTPROTECT, FAIL, "unable to load SOHM master table")
     } /* end if */
     else
@@ -412,7 +412,7 @@ H5SM_get_fheap_addr(H5F_t *f, hid_t dxpl_id, unsigned type_id, haddr_t *fheap_ad
     cache_udata.f = f;
 
     /* Look up the master SOHM table */
-    if(NULL == (table = (H5SM_master_table_t *)H5AC_protect(f, dxpl_id, H5AC_SOHM_TABLE, H5F_SOHM_ADDR(f), &cache_udata, H5AC_READ)))
+    if(NULL == (table = (H5SM_master_table_t *)H5AC_protect(f, dxpl_id, H5AC_SOHM_TABLE, H5F_SOHM_ADDR(f), &cache_udata, H5AC__READ_ONLY_FLAG)))
 	HGOTO_ERROR(H5E_SOHM, H5E_CANTPROTECT, FAIL, "unable to load SOHM master table")
 
     /* Look up index for message type */
@@ -831,7 +831,7 @@ H5SM_convert_btree_to_list(H5F_t * f, H5SM_index_header_t * header, hid_t dxpl_i
     cache_udata.header = header;
 
     /* Protect the SOHM list */
-    if(NULL == (list = (H5SM_list_t *)H5AC_protect(f, dxpl_id, H5AC_SOHM_LIST, header->index_addr, &cache_udata, H5AC_WRITE)))
+    if(NULL == (list = (H5SM_list_t *)H5AC_protect(f, dxpl_id, H5AC_SOHM_LIST, header->index_addr, &cache_udata, H5AC__NO_FLAGS_SET)))
         HGOTO_ERROR(H5E_SOHM, H5E_CANTPROTECT, FAIL, "unable to load SOHM list index")
 
     /* Delete the B-tree and have messages copy themselves to the
@@ -939,7 +939,7 @@ H5SM_can_share(H5F_t *f, hid_t dxpl_id, H5SM_master_table_t *table,
         /* Set up user data for callback */
         cache_udata.f = f;
 
-        if(NULL == (my_table = (H5SM_master_table_t *)H5AC_protect(f, dxpl_id, H5AC_SOHM_TABLE, H5F_SOHM_ADDR(f), &cache_udata, H5AC_READ)))
+        if(NULL == (my_table = (H5SM_master_table_t *)H5AC_protect(f, dxpl_id, H5AC_SOHM_TABLE, H5F_SOHM_ADDR(f), &cache_udata, H5AC__READ_ONLY_FLAG)))
             HGOTO_ERROR(H5E_SOHM, H5E_CANTPROTECT, FAIL, "unable to load SOHM master table")
     } /* end if */
 
@@ -1071,7 +1071,7 @@ H5SM_try_share(H5F_t *f, hid_t dxpl_id, H5O_t *open_oh, unsigned defer_flags,
     cache_udata.f = f;
 
     /* Look up the master SOHM table */
-    if(NULL == (table = (H5SM_master_table_t *)H5AC_protect(f, dxpl_id, H5AC_SOHM_TABLE, H5F_SOHM_ADDR(f), &cache_udata, H5AC_WRITE)))
+    if(NULL == (table = (H5SM_master_table_t *)H5AC_protect(f, dxpl_id, H5AC_SOHM_TABLE, H5F_SOHM_ADDR(f), &cache_udata, H5AC__NO_FLAGS_SET)))
 	HGOTO_ERROR(H5E_SOHM, H5E_CANTPROTECT, FAIL, "unable to load SOHM master table")
 
     /* "complex" sharing checks */
@@ -1277,7 +1277,7 @@ H5SM_write_mesg(H5F_t *f, hid_t dxpl_id, H5O_t *open_oh,
         cache_udata.header = header;
 
         /* The index is a list; get it from the cache */
-        if(NULL == (list = (H5SM_list_t *)H5AC_protect(f, dxpl_id, H5AC_SOHM_LIST, header->index_addr, &cache_udata, defer ? H5AC_READ : H5AC_WRITE)))
+        if(NULL == (list = (H5SM_list_t *)H5AC_protect(f, dxpl_id, H5AC_SOHM_LIST, header->index_addr, &cache_udata, defer ? H5AC__READ_ONLY_FLAG : H5AC__NO_FLAGS_SET)))
 	    HGOTO_ERROR(H5E_SOHM, H5E_CANTPROTECT, FAIL, "unable to load SOHM index")
 
         /* See if the message is already in the index and get its location.
@@ -1530,7 +1530,7 @@ H5SM_delete(H5F_t *f, hid_t dxpl_id, H5O_t *open_oh, H5O_shared_t *sh_mesg)
     cache_udata.f = f;
 
     /* Look up the master SOHM table */
-    if(NULL == (table = (H5SM_master_table_t *)H5AC_protect(f, dxpl_id, H5AC_SOHM_TABLE, H5F_SOHM_ADDR(f), &cache_udata, H5AC_WRITE)))
+    if(NULL == (table = (H5SM_master_table_t *)H5AC_protect(f, dxpl_id, H5AC_SOHM_TABLE, H5F_SOHM_ADDR(f), &cache_udata, H5AC__NO_FLAGS_SET)))
 	HGOTO_ERROR(H5E_SOHM, H5E_CANTPROTECT, FAIL, "unable to load SOHM master table")
 
     /* Find the correct index and try to delete from it */
@@ -1799,7 +1799,7 @@ H5SM_delete_from_index(H5F_t *f, hid_t dxpl_id, H5O_t *open_oh,
         cache_udata.header = header;
 
         /* If the index is stored as a list, get it from the cache */
-        if(NULL == (list = (H5SM_list_t *)H5AC_protect(f, dxpl_id, H5AC_SOHM_LIST, header->index_addr, &cache_udata, H5AC_WRITE)))
+        if(NULL == (list = (H5SM_list_t *)H5AC_protect(f, dxpl_id, H5AC_SOHM_LIST, header->index_addr, &cache_udata, H5AC__NO_FLAGS_SET)))
 	    HGOTO_ERROR(H5E_SOHM, H5E_CANTPROTECT, FAIL, "unable to load SOHM index")
 
         /* Find the message in the list */
@@ -1970,7 +1970,7 @@ H5SM_get_info(const H5O_loc_t *ext_loc, H5P_genplist_t *fc_plist, hid_t dxpl_id)
         cache_udata.f = f;
 
         /* Read the rest of the SOHM table information from the cache */
-        if(NULL == (table = (H5SM_master_table_t *)H5AC_protect(f, dxpl_id, H5AC_SOHM_TABLE, H5F_SOHM_ADDR(f), &cache_udata, H5AC_READ)))
+        if(NULL == (table = (H5SM_master_table_t *)H5AC_protect(f, dxpl_id, H5AC_SOHM_TABLE, H5F_SOHM_ADDR(f), &cache_udata, H5AC__READ_ONLY_FLAG)))
             HGOTO_ERROR(H5E_SOHM, H5E_CANTPROTECT, FAIL, "unable to load SOHM master table")
 
         /* Get index conversion limits */
@@ -2133,7 +2133,7 @@ H5SM_get_refcount(H5F_t *f, hid_t dxpl_id, unsigned type_id,
     tbl_cache_udata.f = f;
 
     /* Look up the master SOHM table */
-    if(NULL == (table = (H5SM_master_table_t *)H5AC_protect(f, dxpl_id, H5AC_SOHM_TABLE, H5F_SOHM_ADDR(f), &tbl_cache_udata, H5AC_READ)))
+    if(NULL == (table = (H5SM_master_table_t *)H5AC_protect(f, dxpl_id, H5AC_SOHM_TABLE, H5F_SOHM_ADDR(f), &tbl_cache_udata, H5AC__READ_ONLY_FLAG)))
 	HGOTO_ERROR(H5E_SOHM, H5E_CANTPROTECT, FAIL, "unable to load SOHM master table")
 
     /* Find the correct index and find the message in it */
@@ -2172,7 +2172,7 @@ H5SM_get_refcount(H5F_t *f, hid_t dxpl_id, unsigned type_id,
         lst_cache_udata.header = header;
 
         /* If the index is stored as a list, get it from the cache */
-        if(NULL == (list = (H5SM_list_t *)H5AC_protect(f, dxpl_id, H5AC_SOHM_LIST, header->index_addr, &lst_cache_udata, H5AC_READ)))
+        if(NULL == (list = (H5SM_list_t *)H5AC_protect(f, dxpl_id, H5AC_SOHM_LIST, header->index_addr, &lst_cache_udata, H5AC__READ_ONLY_FLAG)))
 	    HGOTO_ERROR(H5E_SOHM, H5E_CANTPROTECT, FAIL, "unable to load SOHM index")
 
         /* Find the message in the list */
@@ -2375,7 +2375,7 @@ H5SM_read_mesg(H5F_t *f, const H5SM_sohm_t *mesg, H5HF_t *fheap,
 	        HGOTO_ERROR(H5E_SOHM, H5E_CANTLOAD, FAIL, "unable to open object header")
 
             /* Load the object header from the cache */
-            if(NULL == (oh = H5O_protect(&oloc, dxpl_id, H5AC_READ)))
+            if(NULL == (oh = H5O_protect(&oloc, dxpl_id, H5AC__READ_ONLY_FLAG)))
 	        HGOTO_ERROR(H5E_SOHM, H5E_CANTPROTECT, FAIL, "unable to load object header")
         } /* end if */
         else
@@ -2530,7 +2530,7 @@ H5SM_table_debug(H5F_t *f, hid_t dxpl_id, haddr_t table_addr,
     cache_udata.f = f;
 
     /* Look up the master SOHM table */
-    if(NULL == (table = (H5SM_master_table_t *)H5AC_protect(f, dxpl_id, H5AC_SOHM_TABLE, table_addr, &cache_udata, H5AC_READ)))
+    if(NULL == (table = (H5SM_master_table_t *)H5AC_protect(f, dxpl_id, H5AC_SOHM_TABLE, table_addr, &cache_udata, H5AC__READ_ONLY_FLAG)))
 	HGOTO_ERROR(H5E_SOHM, H5E_CANTPROTECT, FAIL, "unable to load SOHM master table")
 
     HDfprintf(stream, "%*sShared Message Master Table...\n", indent, "");
@@ -2616,7 +2616,7 @@ H5SM_list_debug(H5F_t *f, hid_t dxpl_id, haddr_t list_addr,
     cache_udata.header = &header;
 
     /* Get the list from the cache */
-    if(NULL == (list = (H5SM_list_t *)H5AC_protect(f, dxpl_id, H5AC_SOHM_LIST, list_addr, &cache_udata, H5AC_READ)))
+    if(NULL == (list = (H5SM_list_t *)H5AC_protect(f, dxpl_id, H5AC_SOHM_LIST, list_addr, &cache_udata, H5AC__READ_ONLY_FLAG)))
 	HGOTO_ERROR(H5E_SOHM, H5E_CANTPROTECT, FAIL, "unable to load SOHM index")
 
     HDfprintf(stream, "%*sShared Message List Index...\n", indent, "");
@@ -2693,7 +2693,7 @@ H5SM_ih_size(H5F_t *f, hid_t dxpl_id, hsize_t *hdr_size, H5_ih_info_t *ih_info)
     cache_udata.f = f;
 
     /* Look up the master SOHM table */
-    if(NULL == (table = (H5SM_master_table_t *)H5AC_protect(f, dxpl_id, H5AC_SOHM_TABLE, H5F_SOHM_ADDR(f), &cache_udata, H5AC_READ)))
+    if(NULL == (table = (H5SM_master_table_t *)H5AC_protect(f, dxpl_id, H5AC_SOHM_TABLE, H5F_SOHM_ADDR(f), &cache_udata, H5AC__READ_ONLY_FLAG)))
 	HGOTO_ERROR(H5E_SOHM, H5E_CANTPROTECT, FAIL, "unable to load SOHM master table")
 
     /* Get SOHM header size */
diff --git a/src/H5SMcache.c b/src/H5SMcache.c
index eaeb889..d8c0824 100644
--- a/src/H5SMcache.c
+++ b/src/H5SMcache.c
@@ -47,12 +47,6 @@
 /* Local Macros */
 /****************/
 
-/* Size of stack buffer for serialized tables */
-#define H5SM_TBL_BUF_SIZE       1024
-
-/* Size of stack buffer for serialized list indices */
-#define H5SM_LST_BUF_SIZE       1024
-
 
 /******************/
 /* Local Typedefs */
@@ -64,16 +58,23 @@
 /********************/
 
 /* Metadata cache (H5AC) callbacks */
-static H5SM_master_table_t *H5SM_table_load(H5F_t *f, hid_t dxpl_id, haddr_t addr, void *udata);
-static herr_t H5SM_table_flush(H5F_t *f, hid_t dxpl_id, hbool_t destroy, haddr_t addr, H5SM_master_table_t *table);
-static herr_t H5SM_table_dest(H5F_t *f, H5SM_master_table_t* table);
-static herr_t H5SM_table_clear(H5F_t *f, H5SM_master_table_t *table, hbool_t destroy);
-static herr_t H5SM_table_size(const H5F_t *f, const H5SM_master_table_t *table, size_t *size_ptr);
-static H5SM_list_t *H5SM_list_load(H5F_t *f, hid_t dxpl_id, haddr_t addr, void *udata);
-static herr_t H5SM_list_flush(H5F_t *f, hid_t dxpl_id, hbool_t destroy, haddr_t addr, H5SM_list_t *list);
-static herr_t H5SM_list_dest(H5F_t *f, H5SM_list_t* list);
-static herr_t H5SM_list_clear(H5F_t *f, H5SM_list_t *list, hbool_t destroy);
-static herr_t H5SM_list_size(const H5F_t *f, const H5SM_list_t H5_ATTR_UNUSED *list, size_t *size_ptr);
+static herr_t H5SM__cache_table_get_load_size(const void *udata, size_t *image_len);
+static void *H5SM__cache_table_deserialize(const void *image, size_t len,
+    void *udata, hbool_t *dirty); 
+static herr_t H5SM__cache_table_image_len(const void *thing, size_t *image_len,
+    hbool_t *compressed_ptr, size_t *compressed_image_len_ptr);
+static herr_t H5SM__cache_table_serialize(const H5F_t *f, void *image,
+    size_t len, void *thing); 
+static herr_t H5SM__cache_table_free_icr(void *thing);
+
+static herr_t H5SM__cache_list_get_load_size(const void *udata, size_t *image_len);
+static void *H5SM__cache_list_deserialize(const void *image, size_t len,
+    void *udata, hbool_t *dirty); 
+static herr_t H5SM__cache_list_image_len(const void *thing, size_t *image_len,
+    hbool_t *compressed_ptr, size_t *compressed_image_len_ptr);
+static herr_t H5SM__cache_list_serialize(const H5F_t *f, void *image,
+    size_t len, void *thing);
+static herr_t H5SM__cache_list_free_icr(void *thing);
 
 
 /*********************/
@@ -82,23 +83,35 @@ static herr_t H5SM_list_size(const H5F_t *f, const H5SM_list_t H5_ATTR_UNUSED *l
 
 /* H5SM inherits cache-like properties from H5AC */
 const H5AC_class_t H5AC_SOHM_TABLE[1] = {{
-    H5AC_SOHM_TABLE_ID,
-    (H5AC_load_func_t)H5SM_table_load,
-    (H5AC_flush_func_t)H5SM_table_flush,
-    (H5AC_dest_func_t)H5SM_table_dest,
-    (H5AC_clear_func_t)H5SM_table_clear,
-    (H5AC_notify_func_t)NULL,
-    (H5AC_size_func_t)H5SM_table_size,
+    H5AC_SOHM_TABLE_ID,                 /* Metadata client ID */
+    "shared message table",             /* Metadata client name (for debugging) */
+    H5FD_MEM_SOHM_TABLE,                /* File space memory type for client */
+    H5AC__CLASS_NO_FLAGS_SET,           /* Client class behavior flags */
+    H5SM__cache_table_get_load_size,    /* 'get_load_size' callback */
+    H5SM__cache_table_deserialize,      /* 'deserialize' callback */
+    H5SM__cache_table_image_len,        /* 'image_len' callback */
+    NULL,                               /* 'pre_serialize' callback */
+    H5SM__cache_table_serialize,        /* 'serialize' callback */
+    NULL,                               /* 'notify' callback */
+    H5SM__cache_table_free_icr,         /* 'free_icr' callback */
+    NULL,			        /* 'clear' callback */
+    NULL,                               /* 'fsf_size' callback */
 }};
 
 const H5AC_class_t H5AC_SOHM_LIST[1] = {{
-    H5AC_SOHM_LIST_ID,
-    (H5AC_load_func_t)H5SM_list_load,
-    (H5AC_flush_func_t)H5SM_list_flush,
-    (H5AC_dest_func_t)H5SM_list_dest,
-    (H5AC_clear_func_t)H5SM_list_clear,
-    (H5AC_notify_func_t)NULL,
-    (H5AC_size_func_t)H5SM_list_size,
+    H5AC_SOHM_LIST_ID,                  /* Metadata client ID */
+    "shared message list",              /* Metadata client name (for debugging) */
+    H5FD_MEM_SOHM_TABLE,                /* File space memory type for client */
+    H5AC__CLASS_NO_FLAGS_SET,           /* Client class behavior flags */
+    H5SM__cache_list_get_load_size,     /* 'get_load_size' callback */
+    H5SM__cache_list_deserialize,       /* 'deserialize' callback */
+    H5SM__cache_list_image_len,         /* 'image_len' callback */
+    NULL,                               /* 'pre_serialize' callback */
+    H5SM__cache_list_serialize,         /* 'serialize' callback */
+    NULL,                               /* 'notify' callback */
+    H5SM__cache_list_free_icr,          /* 'free_icr' callback */
+    NULL,			        /* 'clear' callback */
+    NULL,                               /* 'fsf_size' callback */
 }};
 
 
@@ -114,32 +127,76 @@ const H5AC_class_t H5AC_SOHM_LIST[1] = {{
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5SM_table_load
+ * Function:    H5SM__cache_table_get_load_size()
+ *
+ * Purpose:	Return the size of the master table of Shared Object Header 
+ *		Message indexes on disk.  As this cache client doesn't use 
+ *		speculative reads, this value should be accurate.
+ *
+ * Return:      Success:        SUCCEED
+ *              Failure:        FAIL
+ *
+ * Programmer:  John Mainzer
+ *              7/28/14
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+H5SM__cache_table_get_load_size(const void *_udata, size_t *image_len)
+{
+    const H5SM_table_cache_ud_t *udata = (const H5SM_table_cache_ud_t *)_udata;     /* User data for callback */
+
+    FUNC_ENTER_STATIC_NOERR
+
+    /* Check arguments */
+    HDassert(udata);
+    HDassert(udata->f);
+    HDassert(image_len);
+
+    *image_len = H5SM_TABLE_SIZE(udata->f);
+
+    FUNC_LEAVE_NOAPI(SUCCEED)
+} /* end H5SM__cache_table_get_load_size() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:    H5SM__cache_table_deserialize
  *
- * Purpose:	Loads the master table of Shared Object Header Message
- *              indexes.
+ * Purpose:	Given a buffer containing the on disk representation of the 
+ *		master table of Shared Object Header Message indexes, deserialize
+ *		the table, copy the contents into a newly allocated instance of 
+ *		H5SM_master_table_t, and return a pointer to the new instance.
  *
- * Return:	Non-negative on success/Negative on failure
+ * Return:      Success:        Pointer to in core representation
+ *              Failure:        NULL
  *
- * Programmer:	James Laird
- *		November 6, 2006
+ * Programmer:  John Mainzer
+ *              7/28/14
  *
  *-------------------------------------------------------------------------
  */
-static H5SM_master_table_t *
-H5SM_table_load(H5F_t *f, hid_t dxpl_id, haddr_t addr, void H5_ATTR_UNUSED *udata)
+static void *
+H5SM__cache_table_deserialize(const void *_image, size_t len, void *_udata,
+    hbool_t H5_ATTR_UNUSED *dirty)
 {
-    H5SM_master_table_t *table = NULL;
-    H5WB_t        *wb = NULL;         /* Wrapped buffer for table data */
-    uint8_t       tbl_buf[H5SM_TBL_BUF_SIZE]; /* Buffer for table */
-    uint8_t       *buf;               /* Reading buffer */
-    const uint8_t *p;                 /* Pointer into input buffer */
-    uint32_t      stored_chksum;      /* Stored metadata checksum value */
-    uint32_t      computed_chksum;    /* Computed metadata checksum value */
-    size_t        u;                  /* Counter variable for index headers */
-    H5SM_master_table_t *ret_value;
-
-    FUNC_ENTER_NOAPI_NOINIT
+    H5F_t		   *f;                  /* File pointer -- from user data */
+    H5SM_master_table_t    *table = NULL;       /* Shared message table that we deserializing */
+    H5SM_table_cache_ud_t  *udata = (H5SM_table_cache_ud_t *)_udata;    /* Pointer to user data */
+    const uint8_t          *image = (const uint8_t *)_image;    /* Pointer into input buffer */
+    uint32_t                stored_chksum;      /* Stored metadata checksum value */
+    uint32_t                computed_chksum;    /* Computed metadata checksum value */
+    size_t                  u;                  /* Counter variable for index headers */
+    void *                  ret_value;          /* Return value */
+
+    FUNC_ENTER_STATIC
+
+    /* Check arguments */
+    HDassert(image);
+    HDassert(len > 0);
+    HDassert(udata);
+    HDassert(udata->f);
+    f = udata->f;
+    HDassert(dirty);
 
     /* Verify that we're reading version 0 of the table; this is the only
      * version defined so far.
@@ -152,35 +209,18 @@ H5SM_table_load(H5F_t *f, hid_t dxpl_id, haddr_t addr, void H5_ATTR_UNUSED *udat
 
     /* Read number of indexes and version from file superblock */
     table->num_indexes = H5F_SOHM_NINDEXES(f);
-
-    HDassert(addr == H5F_SOHM_ADDR(f));
-    HDassert(addr != HADDR_UNDEF);
     HDassert(table->num_indexes > 0);
 
-    /* Wrap the local buffer for serialized table info */
-    if(NULL == (wb = H5WB_wrap(tbl_buf, sizeof(tbl_buf))))
-        HGOTO_ERROR(H5E_SOHM, H5E_CANTINIT, NULL, "can't wrap buffer")
-
     /* Compute the size of the SOHM table header on disk.  This is the "table"
      * itself plus each index within the table
      */
     table->table_size = H5SM_TABLE_SIZE(f);
-
-    /* Get a pointer to a buffer that's large enough for serialized table */
-    if(NULL == (buf = (uint8_t *)H5WB_actual(wb, table->table_size)))
-        HGOTO_ERROR(H5E_SOHM, H5E_NOSPACE, NULL, "can't get actual buffer")
-
-    /* Read header from disk */
-    if(H5F_block_read(f, H5FD_MEM_SOHM_TABLE, addr, table->table_size, dxpl_id, buf) < 0)
-	HGOTO_ERROR(H5E_SOHM, H5E_READERROR, NULL, "can't read SOHM table")
-
-    /* Get temporary pointer to serialized table */
-    p = buf;
+    HDassert(table->table_size == len);
 
     /* Check magic number */
-    if(HDmemcmp(p, H5SM_TABLE_MAGIC, (size_t)H5_SIZEOF_MAGIC))
-	HGOTO_ERROR(H5E_SOHM, H5E_CANTLOAD, NULL, "bad SOHM table signature")
-    p += H5_SIZEOF_MAGIC;
+    if(HDmemcmp(image, H5SM_TABLE_MAGIC, (size_t)H5_SIZEOF_MAGIC))
+        HGOTO_ERROR(H5E_SOHM, H5E_CANTLOAD, NULL, "bad SOHM table signature")
+    image += H5_SIZEOF_MAGIC;
 
     /* Allocate space for the index headers in memory*/
     if(NULL == (table->indexes = (H5SM_index_header_t *)H5FL_ARR_MALLOC(H5SM_index_header_t, (size_t)table->num_indexes)))
@@ -189,45 +229,45 @@ H5SM_table_load(H5F_t *f, hid_t dxpl_id, haddr_t addr, void H5_ATTR_UNUSED *udat
     /* Read in the index headers */
     for(u = 0; u < table->num_indexes; ++u) {
         /* Verify correct version of index list */
-        if(H5SM_LIST_VERSION != *p++)
+        if(H5SM_LIST_VERSION != *image++) 
             HGOTO_ERROR(H5E_SOHM, H5E_VERSION, NULL, "bad shared message list version number")
 
         /* Type of the index (list or B-tree) */
-        table->indexes[u].index_type= (H5SM_index_type_t)*p++;
+        table->indexes[u].index_type= (H5SM_index_type_t)*image++;
 
         /* Type of messages in the index */
-        UINT16DECODE(p, table->indexes[u].mesg_types);
+        UINT16DECODE(image, table->indexes[u].mesg_types);
 
         /* Minimum size of message to share */
-        UINT32DECODE(p, table->indexes[u].min_mesg_size);
+        UINT32DECODE(image, table->indexes[u].min_mesg_size);
 
         /* List cutoff; fewer than this number and index becomes a list */
-        UINT16DECODE(p, table->indexes[u].list_max);
+        UINT16DECODE(image, table->indexes[u].list_max);
 
         /* B-tree cutoff; more than this number and index becomes a B-tree */
-        UINT16DECODE(p, table->indexes[u].btree_min);
+        UINT16DECODE(image, table->indexes[u].btree_min);
 
         /* Number of messages shared */
-        UINT16DECODE(p, table->indexes[u].num_messages);
+        UINT16DECODE(image, table->indexes[u].num_messages);
 
         /* Address of the actual index */
-        H5F_addr_decode(f, &p, &(table->indexes[u].index_addr));
+        H5F_addr_decode(f, &image, &(table->indexes[u].index_addr));
 
         /* Address of the index's heap */
-        H5F_addr_decode(f, &p, &(table->indexes[u].heap_addr));
+        H5F_addr_decode(f, &image, &(table->indexes[u].heap_addr));
 
         /* Compute the size of a list index for this SOHM index */
         table->indexes[u].list_size = H5SM_LIST_SIZE(f, table->indexes[u].list_max);
     } /* end for */
 
     /* Read in checksum */
-    UINT32DECODE(p, stored_chksum);
+    UINT32DECODE(image, stored_chksum);
 
     /* Sanity check */
-    HDassert((size_t)(p - (const uint8_t *)buf) == table->table_size);
+    HDassert((size_t)(image - (const uint8_t *)_image) == table->table_size);
 
     /* Compute checksum on entire header */
-    computed_chksum = H5_checksum_metadata(buf, (table->table_size - H5SM_SIZEOF_CHECKSUM), 0);
+    computed_chksum = H5_checksum_metadata(_image, (table->table_size - H5SM_SIZEOF_CHECKSUM), 0);
 
     /* Verify checksum */
     if(stored_chksum != computed_chksum)
@@ -237,147 +277,169 @@ H5SM_table_load(H5F_t *f, hid_t dxpl_id, haddr_t addr, void H5_ATTR_UNUSED *udat
     ret_value = table;
 
 done:
-    /* Release resources */
-    if(wb && H5WB_unwrap(wb) < 0)
-        HDONE_ERROR(H5E_SOHM, H5E_CLOSEERROR, NULL, "can't close wrapped buffer")
     if(!ret_value && table)
         if(H5SM_table_free(table) < 0)
             HDONE_ERROR(H5E_SOHM, H5E_CANTFREE, NULL, "unable to destroy sohm table")
 
     FUNC_LEAVE_NOAPI(ret_value)
-} /* end H5SM_table_load() */
+} /* end H5SM__cache_table_deserialize() */
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5SM_table_flush
+ * Function:    H5SM__cache_table_image_len
  *
- * Purpose:	Flushes (and destroys) the table of Shared Object Header
- *              Message indexes.
+ * Purpose:	Compute the size in bytes of the specified instance of
+ *		H5SM_master_table_t on disk, and return it in *image_len.
+ *		On failure, the value of *image_len is undefined.
  *
- * Return:	Non-negative on success/Negative on failure
+ * Return:      Success:        SUCCEED
+ *              Failure:        FAIL
  *
- * Programmer:	James Laird
- *		November 6, 2006
+ * Programmer:  John Mainzer
+ *              7/28/14
  *
  *-------------------------------------------------------------------------
  */
 static herr_t
-H5SM_table_flush(H5F_t *f, hid_t dxpl_id, hbool_t destroy, haddr_t addr, H5SM_master_table_t *table)
+H5SM__cache_table_image_len(const void *_thing, size_t *image_len,
+    hbool_t H5_ATTR_UNUSED *compressed_ptr, size_t H5_ATTR_UNUSED *compressed_image_len_ptr)
 {
-    H5WB_t *wb = NULL;                  /* Wrapped buffer for table data */
-    uint8_t tbl_buf[H5SM_TBL_BUF_SIZE]; /* Buffer for table */
-    herr_t ret_value = SUCCEED;  /* Return value */
+    const H5SM_master_table_t *table = (const H5SM_master_table_t *)_thing;     /* Shared message table to query */
 
-    FUNC_ENTER_NOAPI_NOINIT
+    FUNC_ENTER_STATIC_NOERR
 
-    /* check arguments */
-    HDassert(f);
-    HDassert(H5F_addr_defined(addr));
+    /* Check arguments */
     HDassert(table);
+    HDassert(table->cache_info.magic == H5C__H5C_CACHE_ENTRY_T_MAGIC);
+    HDassert(table->cache_info.type == H5AC_SOHM_TABLE);
+    HDassert(image_len);
 
-    if(table->cache_info.is_dirty) {
-        uint8_t  *buf;               /* Temporary buffer */
-        uint8_t  *p;                 /* Pointer into raw data buffer */
-        uint32_t computed_chksum;    /* Computed metadata checksum value */
-        size_t   u;                  /* Counter variable */
+    *image_len = table->table_size;
 
-        /* Verify that we're writing version 0 of the table; this is the only
-         * version defined so far.
-         */
-        HDassert(H5F_SOHM_VERS(f) == HDF5_SHAREDHEADER_VERSION);
+    FUNC_LEAVE_NOAPI(SUCCEED)
+} /* end H5SM__cache_table_image_len() */
 
-        /* Wrap the local buffer for serialized header info */
-        if(NULL == (wb = H5WB_wrap(tbl_buf, sizeof(tbl_buf))))
-            HGOTO_ERROR(H5E_SOHM, H5E_CANTINIT, FAIL, "can't wrap buffer")
+/***************************************/
+/* no H5SM_cache_table_pre_serialize() */
+/***************************************/
 
-        /* Get a pointer to a buffer that's large enough for serialized table */
-        if(NULL == (buf = (uint8_t *)H5WB_actual(wb, table->table_size)))
-            HGOTO_ERROR(H5E_SOHM, H5E_NOSPACE, FAIL, "can't get actual buffer")
+
+/*-------------------------------------------------------------------------
+ * Function:    H5SM__cache_table_serialize
+ *
+ * Purpose:	Serialize the contents of the supplied shared message table, and
+ *		load this data into the supplied buffer.
+ *
+ * Return:      Success:        SUCCEED
+ *              Failure:        FAIL
+ *
+ * Programmer:  John Mainzer
+ *              7/28/14
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+H5SM__cache_table_serialize(const H5F_t *f, void *_image, size_t len,
+    void *_thing)
+{
+    H5SM_master_table_t *table = (H5SM_master_table_t *)_thing; /* Shared message table to encode */
+    uint8_t            *image = (uint8_t *)_image;      /* Pointer into raw data buffer */
+    uint32_t            computed_chksum;    /* Computed metadata checksum value */
+    size_t              u;                  /* Counter variable */
 
-        /* Get temporary pointer to buffer for serialized table */
-        p = buf;
+    FUNC_ENTER_STATIC_NOERR
 
-        /* Encode magic number */
-        HDmemcpy(p, H5SM_TABLE_MAGIC, (size_t)H5_SIZEOF_MAGIC);
-        p += H5_SIZEOF_MAGIC;
+    /* Check arguments */
+    HDassert(f);
+    HDassert(image);
+    HDassert(table);
+    HDassert(table->cache_info.magic == H5C__H5C_CACHE_ENTRY_T_MAGIC);
+    HDassert(table->cache_info.type == H5AC_SOHM_TABLE);
+    HDassert(table->table_size == len);
 
-        /* Encode each index header */
-        for(u = 0; u < table->num_indexes; ++u) {
-            /* Version for this list */
-            *p++ = H5SM_LIST_VERSION;
+    /* Verify that we're writing version 0 of the table; this is the only
+     * version defined so far.
+     */
+    HDassert(H5F_SOHM_VERS(f) == HDF5_SHAREDHEADER_VERSION);
 
-            /* Is message index a list or a B-tree? */
-            *p++ = table->indexes[u].index_type;
+    /* Encode magic number */
+    HDmemcpy(image, H5SM_TABLE_MAGIC, (size_t)H5_SIZEOF_MAGIC);
+    image += H5_SIZEOF_MAGIC;
 
-            /* Type of messages in the index */
-            UINT16ENCODE(p, table->indexes[u].mesg_types);
+    /* Encode each index header */
+   for(u = 0; u < table->num_indexes; ++u) {
+        /* Version for this list */
+        *image++ = H5SM_LIST_VERSION;
 
-            /* Minimum size of message to share */
-            UINT32ENCODE(p, table->indexes[u].min_mesg_size);
+        /* Is message index a list or a B-tree? */
+        *image++ = table->indexes[u].index_type;
 
-            /* List cutoff; fewer than this number and index becomes a list */
-            UINT16ENCODE(p, table->indexes[u].list_max);
+        /* Type of messages in the index */
+        UINT16ENCODE(image, table->indexes[u].mesg_types);
 
-            /* B-tree cutoff; more than this number and index becomes a B-tree */
-            UINT16ENCODE(p, table->indexes[u].btree_min);
+        /* Minimum size of message to share */
+        UINT32ENCODE(image, table->indexes[u].min_mesg_size);
 
-            /* Number of messages shared */
-            UINT16ENCODE(p, table->indexes[u].num_messages);
+        /* List cutoff; fewer than this number and index becomes a list */
+        UINT16ENCODE(image, table->indexes[u].list_max);
 
-            /* Address of the actual index */
-            H5F_addr_encode(f, &p, table->indexes[u].index_addr);
+        /* B-tree cutoff; more than this number and index becomes a B-tree */
+        UINT16ENCODE(image, table->indexes[u].btree_min);
 
-            /* Address of the index's heap */
-            H5F_addr_encode(f, &p, table->indexes[u].heap_addr);
-        } /* end for */
+        /* Number of messages shared */
+        UINT16ENCODE(image, table->indexes[u].num_messages);
 
-        /* Compute checksum on buffer */
-        computed_chksum = H5_checksum_metadata(buf, (table->table_size - H5SM_SIZEOF_CHECKSUM), 0);
-        UINT32ENCODE(p, computed_chksum);
+        /* Address of the actual index */
+        H5F_addr_encode(f, &image, table->indexes[u].index_addr);
 
-        /* Write the table to disk */
-        HDassert((size_t)(p - buf) == table->table_size);
-	if(H5F_block_write(f, H5FD_MEM_SOHM_TABLE, addr, table->table_size, dxpl_id, buf) < 0)
-	    HGOTO_ERROR(H5E_SOHM, H5E_CANTFLUSH, FAIL, "unable to save sohm table to disk")
+        /* Address of the index's heap */
+        H5F_addr_encode(f, &image, table->indexes[u].heap_addr);
+    } /* end for */
 
-	table->cache_info.is_dirty = FALSE;
-    } /* end if */
+    /* Compute checksum on buffer */
+    computed_chksum = H5_checksum_metadata(_image, (table->table_size - H5SM_SIZEOF_CHECKSUM), 0);
+    UINT32ENCODE(image, computed_chksum);
 
-    if(destroy)
-        if(H5SM_table_dest(f, table) < 0)
-	    HGOTO_ERROR(H5E_SOHM, H5E_CANTFREE, FAIL, "unable to destroy sohm table")
+    /* sanity check */
+    HDassert((size_t)(image - ((uint8_t *)_image)) == table->table_size);
 
-done:
-    /* Release resources */
-    if(wb && H5WB_unwrap(wb) < 0)
-        HDONE_ERROR(H5E_SOHM, H5E_CLOSEERROR, FAIL, "can't close wrapped buffer")
+    FUNC_LEAVE_NOAPI(SUCCEED)
+} /* end H5SM__cache_table_serialize() */
 
-    FUNC_LEAVE_NOAPI(ret_value)
-} /* end H5SM_table_flush() */
+/*****************************************/
+/* no H5SM_cache_table_notify() function */
+/*****************************************/
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5SM_table_dest
+ * Function:    H5SM__cache_table_free_icr
  *
- * Purpose:	Frees memory used by the SOHM table.
+ * Purpose:	Free memory used by the SOHM table.
  *
- * Return:	Non-negative on success/Negative on failure
+ * Note:	The metadata cache sets the object's cache_info.magic to
+ *		H5C__H5C_CACHE_ENTRY_T_BAD_MAGIC before calling a free_icr
+ *		callback (checked in assert).
  *
- * Programmer:	James Laird
- *		November 6, 2006
+ * Return:      Success:        SUCCEED
+ *              Failure:        FAIL
+ *
+ * Programmer:  John Mainzer
+ *              7/28/14
  *
  *-------------------------------------------------------------------------
  */
 static herr_t
-H5SM_table_dest(H5F_t H5_ATTR_UNUSED *f, H5SM_master_table_t* table)
+H5SM__cache_table_free_icr(void *_thing)
 {
-    herr_t ret_value = SUCCEED;         /* Return value */
+    H5SM_master_table_t *table = (H5SM_master_table_t *)_thing;  /* Shared message table to release */
+    herr_t               ret_value = SUCCEED;    /* Return value */
 
-    FUNC_ENTER_NOAPI_NOINIT
+    FUNC_ENTER_STATIC
 
     /* Check arguments */
     HDassert(table);
-    HDassert(table->indexes);
+    HDassert(table->cache_info.magic == H5C__H5C_CACHE_ENTRY_T_BAD_MAGIC);
+    HDassert(table->cache_info.type == H5AC_SOHM_TABLE);
 
     /* Destroy Shared Object Header Message table */
     if(H5SM_table_free(table) < 0)
@@ -385,105 +447,80 @@ H5SM_table_dest(H5F_t H5_ATTR_UNUSED *f, H5SM_master_table_t* table)
 
 done:
     FUNC_LEAVE_NOAPI(ret_value)
-} /* end H5SM_table_dest() */
+} /* end H5SM_cache_table_free_icr() */
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5SM_table_clear
+ * Function:    H5SM__cache_list_get_load_size()
  *
- * Purpose:	Mark this table as no longer being dirty.
+ * Purpose:	Return the on disk size of list of SOHM messages.  In this case,
+ *		we simply look up the size in the user data, and return that value
+ *		in *image_len.
  *
- * Return:	Non-negative on success/Negative on failure
+ * Return:      Success:        SUCCEED
+ *              Failure:        FAIL
  *
- * Programmer:	James Laird
- *		November 6, 2006
+ * Programmer:  John Mainzer
+ *              7/28/14
  *
  *-------------------------------------------------------------------------
  */
 static herr_t
-H5SM_table_clear(H5F_t *f, H5SM_master_table_t *table, hbool_t destroy)
+H5SM__cache_list_get_load_size(const void *_udata, size_t *image_len)
 {
-    herr_t ret_value = SUCCEED;         /* Return value */
-
-    FUNC_ENTER_NOAPI_NOINIT
-
-    /*
-     * Check arguments.
-     */
-    HDassert(table);
-
-    /* Reset the dirty flag.  */
-    table->cache_info.is_dirty = FALSE;
-
-    if(destroy)
-        if(H5SM_table_dest(f, table) < 0)
-	    HGOTO_ERROR(H5E_SOHM, H5E_CANTFREE, FAIL, "unable to delete SOHM master table")
-
-done:
-    FUNC_LEAVE_NOAPI(ret_value)
-} /* end H5SM_table_clear() */
+    const H5SM_list_cache_ud_t *udata = (const H5SM_list_cache_ud_t *)_udata;        /* User data for callback */
 
-
-/*-------------------------------------------------------------------------
- * Function:	H5SM_table_size
- *
- * Purpose:	Returns the size of the table encoded on disk.
- *
- * Return:	Non-negative on success/Negative on failure
- *
- * Programmer:	James Laird
- *		November 6, 2006
- *
- *-------------------------------------------------------------------------
- */
-static herr_t
-H5SM_table_size(const H5F_t H5_ATTR_UNUSED *f, const H5SM_master_table_t *table, size_t *size_ptr)
-{
-    FUNC_ENTER_NOAPI_NOINIT_NOERR
+    FUNC_ENTER_STATIC_NOERR
 
     /* Check arguments */
-    HDassert(f);
-    HDassert(table);
-    HDassert(size_ptr);
+    HDassert(udata);
+    HDassert(udata->header);
+    HDassert(udata->header->list_size > 0);
+    HDassert(image_len);
 
-    /* Set size value */
-    *size_ptr = table->table_size;
+    *image_len = udata->header->list_size;
 
     FUNC_LEAVE_NOAPI(SUCCEED)
-} /* end H5SM_table_size() */
+} /* end H5SM__cache_list_get_load_size() */
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5SM_list_load
+ * Function:    H5SM__cache_list_deserialize
  *
- * Purpose:	Loads a list of SOHM messages.
+ * Purpose:	Given a buffer containing the on disk image of a list of 
+ *		SOHM message, deserialize the list, load it into a newly allocated 
+ *		instance of H5SM_list_t, and return a pointer to same.
  *
- * Return:	Non-negative on success/Negative on failure
+ * Return:      Success:        Pointer to in core representation
+ *              Failure:        NULL
  *
- * Programmer:	James Laird
- *		November 6, 2006
+ * Programmer:  John Mainzer
+ *              7/28/14
  *
  *-------------------------------------------------------------------------
  */
-static H5SM_list_t *
-H5SM_list_load(H5F_t *f, hid_t dxpl_id, haddr_t addr, void *_udata)
+static void *
+H5SM__cache_list_deserialize(const void *_image, size_t len, void *_udata,
+    hbool_t H5_ATTR_UNUSED *dirty)
 {
-    H5SM_list_t *list;          /* The SOHM list being read in */
-    H5SM_list_cache_ud_t *udata = (H5SM_list_cache_ud_t *)_udata; /* User data for callback */
-    H5SM_bt2_ctx_t ctx;         /* Message encoding context */
-    H5WB_t *wb = NULL;          /* Wrapped buffer for list index data */
-    uint8_t lst_buf[H5SM_LST_BUF_SIZE]; /* Buffer for list index */
-    uint8_t *buf;               /* Reading buffer */
-    uint8_t *p;                 /* Pointer into input buffer */
-    uint32_t stored_chksum;     /* Stored metadata checksum value */
-    uint32_t computed_chksum;   /* Computed metadata checksum value */
-    size_t u;                   /* Counter variable for messages in list */
-    H5SM_list_t *ret_value;     /* Return value */
+    H5SM_list_t          *list = NULL;     /* The SOHM list being read in */
+    H5SM_list_cache_ud_t *udata = (H5SM_list_cache_ud_t *)_udata;    /* User data for callback */
+    H5SM_bt2_ctx_t        ctx;             /* Message encoding context */
+    const uint8_t        *image = (const uint8_t *)_image;      /* Pointer into input buffer */
+    uint32_t              stored_chksum;   /* Stored metadata checksum value */
+    uint32_t              computed_chksum; /* Computed metadata checksum value */
+    size_t                u;               /* Counter variable for messages in list */
+    void *                ret_value;       /* Return value */
 
-    FUNC_ENTER_NOAPI_NOINIT
+    FUNC_ENTER_STATIC
 
     /* Check arguments */
+    HDassert(image);
+    HDassert(len > 0);
+    HDassert(udata);
     HDassert(udata->header);
+    HDassert(udata->header->list_size == len);
+    HDassert(dirty);
 
     /* Allocate space for the SOHM list data structure */
     if(NULL == (list = H5FL_MALLOC(H5SM_list_t)))
@@ -495,42 +532,28 @@ H5SM_list_load(H5F_t *f, hid_t dxpl_id, haddr_t addr, void *_udata)
         HGOTO_ERROR(H5E_SOHM, H5E_NOSPACE, NULL, "file allocation failed for SOHM list")
     list->header = udata->header;
 
-    /* Wrap the local buffer for serialized list index info */
-    if(NULL == (wb = H5WB_wrap(lst_buf, sizeof(lst_buf))))
-        HGOTO_ERROR(H5E_SOHM, H5E_CANTINIT, NULL, "can't wrap buffer")
-
-    /* Get a pointer to a buffer that's large enough for serialized list index */
-    if(NULL == (buf = (uint8_t *)H5WB_actual(wb, udata->header->list_size)))
-        HGOTO_ERROR(H5E_SOHM, H5E_NOSPACE, NULL, "can't get actual buffer")
-
-    /* Read list from disk */
-    if(H5F_block_read(f, H5FD_MEM_SOHM_INDEX, addr, udata->header->list_size, dxpl_id, buf) < 0)
-	HGOTO_ERROR(H5E_SOHM, H5E_READERROR, NULL, "can't read SOHM list")
-
-    /* Get temporary pointer to serialized list index */
-    p = buf;
-
     /* Check magic number */
-    if(HDmemcmp(p, H5SM_LIST_MAGIC, (size_t)H5_SIZEOF_MAGIC))
+    if(HDmemcmp(image, H5SM_LIST_MAGIC, (size_t)H5_SIZEOF_MAGIC))
         HGOTO_ERROR(H5E_SOHM, H5E_CANTLOAD, NULL, "bad SOHM list signature")
-    p += H5_SIZEOF_MAGIC;
+    image += H5_SIZEOF_MAGIC;
 
     /* Read messages into the list array */
     ctx.sizeof_addr = H5F_SIZEOF_ADDR(udata->f);
     for(u = 0; u < udata->header->num_messages; u++) {
-        if(H5SM_message_decode(p, &(list->messages[u]), &ctx) < 0)
+        if(H5SM_message_decode(image, &(list->messages[u]), &ctx) < 0)
             HGOTO_ERROR(H5E_SOHM, H5E_CANTLOAD, NULL, "can't decode shared message")
-        p += H5SM_SOHM_ENTRY_SIZE(udata->f);
+
+        image += H5SM_SOHM_ENTRY_SIZE(udata->f);
     } /* end for */
 
     /* Read in checksum */
-    UINT32DECODE(p, stored_chksum);
+    UINT32DECODE(image, stored_chksum);
 
     /* Sanity check */
-    HDassert((size_t)(p - buf) <= udata->header->list_size);
+    HDassert((size_t)(image - (const uint8_t *)_image) <= udata->header->list_size);
 
     /* Compute checksum on entire header */
-    computed_chksum = H5_checksum_metadata(buf, ((size_t)(p - buf) - H5SM_SIZEOF_CHECKSUM), 0);
+    computed_chksum = H5_checksum_metadata(_image, ((size_t)(image - (const uint8_t *)_image) - H5SM_SIZEOF_CHECKSUM), 0);
 
     /* Verify checksum */
     if(stored_chksum != computed_chksum)
@@ -544,9 +567,6 @@ H5SM_list_load(H5F_t *f, hid_t dxpl_id, haddr_t addr, void *_udata)
     ret_value = list;
 
 done:
-    /* Release resources */
-    if(wb && H5WB_unwrap(wb) < 0)
-        HDONE_ERROR(H5E_SOHM, H5E_CLOSEERROR, NULL, "can't close wrapped buffer")
     if(!ret_value && list) {
         if(list->messages)
             list->messages = H5FL_ARR_FREE(H5SM_sohm_t, list->messages);
@@ -554,205 +574,158 @@ done:
     } /* end if */
 
     FUNC_LEAVE_NOAPI(ret_value)
-} /* end H5SM_list_load() */
+} /* end H5SM__cache_list_deserialize() */
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5SM_list_flush
+ * Function:    H5SM__cache_list_image_len
  *
- * Purpose:	Flush this list index.
+ * Purpose:	Get the size of the shared message list on disk.
  *
- * Return:	Non-negative on success/Negative on failure
+ * Return:      Success:        SUCCEED
+ *              Failure:        FAIL
  *
- * Programmer:	James Laird
- *		November 6, 2006
+ * Programmer:  John Mainzer
+ *              7/28/14
  *
  *-------------------------------------------------------------------------
  */
 static herr_t
-H5SM_list_flush(H5F_t *f, hid_t dxpl_id, hbool_t destroy, haddr_t addr, H5SM_list_t *list)
+H5SM__cache_list_image_len(const void *_thing, size_t *image_len,
+    hbool_t H5_ATTR_UNUSED *compressed_ptr, size_t H5_ATTR_UNUSED *compressed_image_len_ptr)
 {
-    H5WB_t *wb = NULL;                  /* Wrapped buffer for list index data */
-    uint8_t lst_buf[H5SM_LST_BUF_SIZE]; /* Buffer for list index */
-    herr_t ret_value = SUCCEED;         /* Return value */
+    const H5SM_list_t *list = (const H5SM_list_t *)_thing;      /* Shared message list to query */
 
-    FUNC_ENTER_NOAPI_NOINIT
+    FUNC_ENTER_STATIC_NOERR
 
-    /* check arguments */
-    HDassert(f);
-    HDassert(H5F_addr_defined(addr));
+    /* Check arguments */
     HDassert(list);
+    HDassert(list->cache_info.magic == H5C__H5C_CACHE_ENTRY_T_MAGIC);
+    HDassert(list->cache_info.type == H5AC_SOHM_LIST);
     HDassert(list->header);
+    HDassert(image_len);
 
-    if(list->cache_info.is_dirty) {
-        H5SM_bt2_ctx_t ctx;         /* Message encoding context */
-        uint8_t *buf;               /* Temporary buffer */
-        uint8_t *p;                 /* Pointer into raw data buffer */
-        uint32_t computed_chksum;   /* Computed metadata checksum value */
-        size_t mesgs_written;       /* Number of messages written to list */
-        size_t u;                   /* Local index variable */
-
-        /* Wrap the local buffer for serialized list index info */
-        if(NULL == (wb = H5WB_wrap(lst_buf, sizeof(lst_buf))))
-            HGOTO_ERROR(H5E_SOHM, H5E_CANTINIT, FAIL, "can't wrap buffer")
-
-        /* Get a pointer to a buffer that's large enough for serialized list index */
-        if(NULL == (buf = (uint8_t *)H5WB_actual(wb, list->header->list_size)))
-            HGOTO_ERROR(H5E_SOHM, H5E_NOSPACE, FAIL, "can't get actual buffer")
-
-        /* Get temporary pointer to buffer for serialized list index */
-        p = buf;
-
-        /* Encode magic number */
-        HDmemcpy(p, H5SM_LIST_MAGIC, (size_t)H5_SIZEOF_MAGIC);
-        p += H5_SIZEOF_MAGIC;
-
-        /* Write messages from the messages array to disk */
-        mesgs_written = 0;
-        ctx.sizeof_addr = H5F_SIZEOF_ADDR(f);
-        for(u = 0; u < list->header->list_max && mesgs_written < list->header->num_messages; u++) {
-            if(list->messages[u].location != H5SM_NO_LOC) {
-                if(H5SM_message_encode(p, &(list->messages[u]), &ctx) < 0)
-                    HGOTO_ERROR(H5E_SOHM, H5E_CANTFLUSH, FAIL, "unable to write shared message to disk")
-
-                p += H5SM_SOHM_ENTRY_SIZE(f);
-                ++mesgs_written;
-            } /* end if */
-        } /* end for */
-        HDassert(mesgs_written == list->header->num_messages);
-
-        /* Compute checksum on buffer */
-        computed_chksum = H5_checksum_metadata(buf, (size_t)(p - buf), 0);
-        UINT32ENCODE(p, computed_chksum);
-#ifdef H5_CLEAR_MEMORY
-HDmemset(p, 0, (list->header->list_size - (size_t)(p - buf)));
-#endif /* H5_CLEAR_MEMORY */
+    *image_len = list->header->list_size;
 
-        /* Write the list to disk */
-        HDassert((size_t)(p - buf) <= list->header->list_size);
-	if(H5F_block_write(f, H5FD_MEM_SOHM_INDEX, addr, list->header->list_size, dxpl_id, buf) < 0)
-	    HGOTO_ERROR(H5E_SOHM, H5E_CANTFLUSH, FAIL, "unable to save sohm table to disk")
-
-        list->cache_info.is_dirty = FALSE;
-    } /* end if */
-
-    if(destroy)
-        if(H5SM_list_dest(f, list) < 0)
-	    HGOTO_ERROR(H5E_SOHM, H5E_CANTFREE, FAIL, "unable to destroy list")
-
-done:
-    /* Release resources */
-    if(wb && H5WB_unwrap(wb) < 0)
-        HDONE_ERROR(H5E_SOHM, H5E_CLOSEERROR, FAIL, "can't close wrapped buffer")
+    FUNC_LEAVE_NOAPI(SUCCEED)
+} /* end H5SM__cache_list_image_len() */
 
-    FUNC_LEAVE_NOAPI(ret_value)
-} /* end H5SM_list_flush() */
+/**************************************/
+/* no H5SM_cache_list_pre_serialize() */
+/**************************************/
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5SM_list_dest
+ * Function:    H5SM__cache_list_serialize
  *
- * Purpose:	Frees all memory used by the list.
+ * Purpose:	Serialize the contents of the supplied shared message list, and
+ *		load this data into the supplied buffer.
  *
- * Return:	Non-negative on success/Negative on failure
+ * Return:      Success:        SUCCEED
+ *              Failure:        FAIL
  *
- * Programmer:	James Laird
- *		November 6, 2006
+ * Programmer:  John Mainzer
+ *              7/28/14
  *
  *-------------------------------------------------------------------------
  */
 static herr_t
-H5SM_list_dest(H5F_t *f, H5SM_list_t* list)
+H5SM__cache_list_serialize(const H5F_t *f, void *_image, size_t len,
+    void *_thing)
 {
-    herr_t ret_value = SUCCEED;         /* Return value */
+    H5SM_list_t *list = (H5SM_list_t *)_thing ;   /* Instance being serialized */
+    H5SM_bt2_ctx_t ctx;         /* Message encoding context */
+    uint8_t *image = (uint8_t *)_image;         /* Pointer into raw data buffer */
+    uint32_t computed_chksum;   /* Computed metadata checksum value */
+    size_t mesgs_serialized;    /* Number of messages serialized */
+    size_t u;                   /* Local index variable */
+    herr_t       ret_value = SUCCEED;    /* Return value */
 
-    FUNC_ENTER_NOAPI_NOINIT
+    FUNC_ENTER_STATIC
 
-    /* Sanity check */
+    /* Check arguments */
+    HDassert(f);
+    HDassert(image);
     HDassert(list);
+    HDassert(list->cache_info.magic == H5C__H5C_CACHE_ENTRY_T_MAGIC);
+    HDassert(list->cache_info.type == H5AC_SOHM_LIST);
     HDassert(list->header);
-    HDassert(list->messages);
+    HDassert(list->header->list_size == len);
+
+    /* Encode magic number */
+    HDmemcpy(image, H5SM_LIST_MAGIC, (size_t)H5_SIZEOF_MAGIC);
+    image += H5_SIZEOF_MAGIC;
+
+    /* serialize messages from the messages array */
+    mesgs_serialized = 0;
+    ctx.sizeof_addr = H5F_SIZEOF_ADDR(f);
+    for(u = 0; ((u < list->header->list_max) && (mesgs_serialized < list->header->num_messages)); u++) {
+        if(list->messages[u].location != H5SM_NO_LOC) {
+            if(H5SM_message_encode(image, &(list->messages[u]), &ctx) < 0)
+                HGOTO_ERROR(H5E_SOHM, H5E_CANTFLUSH, FAIL, "unable to serialize shared message")
+
+            image += H5SM_SOHM_ENTRY_SIZE(f);
+            ++mesgs_serialized;
+        } /* end if */
+    } /* end for */
 
-    /* If we're going to free the space on disk, the address must be valid */
-    HDassert(!list->cache_info.free_file_space_on_destroy || H5F_addr_defined(list->cache_info.addr));
+    HDassert(mesgs_serialized == list->header->num_messages);
 
-    /* Check for freeing file space for shared message index list */
-    if(list->cache_info.free_file_space_on_destroy) {
-        /* Release the space on disk */
-        /* (XXX: Nasty usage of internal DXPL value! -QAK) */
-        if(H5MF_xfree(f, H5FD_MEM_SOHM_INDEX, H5AC_dxpl_id, list->cache_info.addr, (hsize_t)list->header->list_size) < 0)
-            HGOTO_ERROR(H5E_SOHM, H5E_NOSPACE, FAIL, "unable to free shared message list")
-    } /* end if */
+    /* Compute checksum on buffer */
+    computed_chksum = H5_checksum_metadata(_image, (size_t)(image - (uint8_t *)_image), 0);
+    UINT32ENCODE(image, computed_chksum);
 
-    /* Destroy Shared Object Header Message list */
-    if(H5SM_list_free(list) < 0)
-        HGOTO_ERROR(H5E_SOHM, H5E_CANTRELEASE, FAIL, "unable to free shared message list")
+#ifdef H5_CLEAR_MEMORY
+    HDmemset(image, 0, (list->header->list_size - (size_t)(image - (uint8_t *)_image)));
+#endif /* H5_CLEAR_MEMORY */
+
+    /* sanity check */
+    HDassert((size_t)(image - (uint8_t *)_image) <= list->header->list_size);
 
 done:
     FUNC_LEAVE_NOAPI(ret_value)
-} /* end H5SM_list_dest() */
+} /* end H5SM__cache_list_serialize() */
+
+/****************************************/
+/* no H5SM_cache_list_notify() function */
+/****************************************/
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5SM_list_clear
+ * Function:    H5SM__cache_list_free_icr
  *
- * Purpose:	Marks a list as not dirty.
+ * Purpose:	Free all memory used by the list.
  *
- * Return:	Non-negative on success/Negative on failure
+ * Note:	The metadata cache sets the object's cache_info.magic to
+ *		H5C__H5C_CACHE_ENTRY_T_BAD_MAGIC before calling a free_icr
+ *		callback (checked in assert).
  *
- * Programmer:	James Laird
- *		November 6, 2006
+ * Return:      Success:        SUCCEED
+ *              Failure:        FAIL
+ *
+ * Programmer:  John Mainzer
+ *              7/28/14
  *
  *-------------------------------------------------------------------------
  */
 static herr_t
-H5SM_list_clear(H5F_t *f, H5SM_list_t *list, hbool_t destroy)
+H5SM__cache_list_free_icr(void *_thing)
 {
-    herr_t ret_value = SUCCEED;         /* Return value */
+    H5SM_list_t *list = (H5SM_list_t *)_thing;  /* Shared message list to release */
+    herr_t       ret_value = SUCCEED;    /* Return value */
 
-    FUNC_ENTER_NOAPI_NOINIT
+    FUNC_ENTER_STATIC
 
     /* Check arguments */
     HDassert(list);
+    HDassert(list->cache_info.magic == H5C__H5C_CACHE_ENTRY_T_BAD_MAGIC);
+    HDassert(list->cache_info.type == H5AC_SOHM_LIST);
 
-    /* Reset the dirty flag.  */
-    list->cache_info.is_dirty = FALSE;
-
-    if(destroy)
-        if(H5SM_list_dest(f, list) < 0)
-	    HGOTO_ERROR(H5E_SOHM, H5E_CANTFREE, FAIL, "unable to destroy SOHM list")
+    /* Destroy Shared Object Header Message list */
+    if(H5SM_list_free(list) < 0)
+        HGOTO_ERROR(H5E_SOHM, H5E_CANTRELEASE, FAIL, "unable to free shared message list")
 
 done:
     FUNC_LEAVE_NOAPI(ret_value)
-} /* end of H5SM_list_clear() */
-
-
-/*-------------------------------------------------------------------------
- * Function:	H5SM_list_size
- *
- * Purpose:	Gets the size of a list on disk.
- *
- * Return:	Non-negative on success/Negative on failure
- *
- * Programmer:	James Laird
- *		November 6, 2006
- *
- *-------------------------------------------------------------------------
- */
-static herr_t
-H5SM_list_size(const H5F_t H5_ATTR_UNUSED *f, const H5SM_list_t *list, size_t *size_ptr)
-{
-    FUNC_ENTER_NOAPI_NOINIT_NOERR
-
-    /* check arguments */
-    HDassert(f);
-    HDassert(list);
-    HDassert(list->header);
-    HDassert(size_ptr);
-
-    /* Set size value */
-    *size_ptr = list->header->list_size;
-
-    FUNC_LEAVE_NOAPI(SUCCEED)
-} /* end H5SM_list_size() */
+} /* end H5O_cache_list_free_icr() */
 
diff --git a/src/H5SMtest.c b/src/H5SMtest.c
index 12ed766..c4e02bc 100644
--- a/src/H5SMtest.c
+++ b/src/H5SMtest.c
@@ -98,7 +98,7 @@ H5SM_get_mesg_count_test(H5F_t *f, hid_t dxpl_id, unsigned type_id,
         cache_udata.f = f;
 
         /* Look up the master SOHM table */
-        if(NULL == (table = (H5SM_master_table_t *)H5AC_protect(f, dxpl_id, H5AC_SOHM_TABLE, H5F_SOHM_ADDR(f), &cache_udata, H5AC_READ)))
+        if(NULL == (table = (H5SM_master_table_t *)H5AC_protect(f, dxpl_id, H5AC_SOHM_TABLE, H5F_SOHM_ADDR(f), &cache_udata, H5AC__READ_ONLY_FLAG)))
             HGOTO_ERROR(H5E_SOHM, H5E_CANTPROTECT, FAIL, "unable to load SOHM master table")
 
         /* Find the correct index for this message type */