Final merge of page buffering branch to develop

52 files changed, 7486 insertions, 1717 deletions

diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index ef361b2..9321bbd 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -195,6 +195,7 @@ set (H5F_SOURCES
     ${HDF5_SRC_DIR}/H5Fmpi.c
     ${HDF5_SRC_DIR}/H5Fquery.c
     ${HDF5_SRC_DIR}/H5Fsfile.c
+    ${HDF5_SRC_DIR}/H5Fspace.c
     ${HDF5_SRC_DIR}/H5Fsuper.c
     ${HDF5_SRC_DIR}/H5Fsuper_cache.c
     ${HDF5_SRC_DIR}/H5Ftest.c
@@ -504,6 +505,15 @@ set (H5P_HDRS
 )
 IDE_GENERATED_PROPERTIES ("H5P" "${H5P_HDRS}" "${H5P_SOURCES}" )
 
+set (H5PB_SOURCES
+    ${HDF5_SRC_DIR}/H5PB.c
+)
+
+set (H5PB_HDRS
+    ${HDF5_SRC_DIR}/H5PBpkg.h
+)
+IDE_GENERATED_PROPERTIES ("H5PB" "${H5PB_HDRS}" "${H5PB_SOURCES}" )
+
 set (H5PL_SOURCES
     ${HDF5_SRC_DIR}/H5PL.c
 )
@@ -699,6 +709,7 @@ set (common_SRCS
     ${H5MP_SOURCES}
     ${H5O_SOURCES}
     ${H5P_SOURCES}
+    ${H5PB_SOURCES}
     ${H5PL_SOURCES}
     ${H5R_SOURCES}
     ${H5UC_SOURCES}
@@ -739,6 +750,7 @@ set (H5_PUBLIC_HEADERS
     ${H5MP_HDRS}
     ${H5O_HDRS}
     ${H5P_HDRS}
+    ${H5PB_HDRS}
     ${H5PL_HDRS}
     ${H5R_HDRS}
     ${H5S_HDRS}
@@ -777,6 +789,7 @@ set (H5_PRIVATE_HEADERS
     ${HDF5_SRC_DIR}/H5MPprivate.h
     ${HDF5_SRC_DIR}/H5Oprivate.h
     ${HDF5_SRC_DIR}/H5Pprivate.h
+    ${HDF5_SRC_DIR}/H5PBprivate.h
     ${HDF5_SRC_DIR}/H5PLprivate.h
     ${HDF5_SRC_DIR}/H5UCprivate.h
     ${HDF5_SRC_DIR}/H5Rprivate.h
diff --git a/src/H5AC.c b/src/H5AC.c
index 2fb7992..a561852 100644
--- a/src/H5AC.c
+++ b/src/H5AC.c
@@ -353,6 +353,44 @@ H5AC_term_package(void)
 
 
 /*-------------------------------------------------------------------------
+ *
+ * Function:    H5AC_cache_image_pending()
+ *
+ * Purpose:     Debugging function that tests to see if the load of a 
+ *              metadata cache image load is pending (i.e. will be executed
+ *              on the next protect or insert)
+ *              
+ *              Returns TRUE if a cache image load is pending, and FALSE
+ *              if not.  Throws an assertion failure on error.
+ *
+ * Return:      TRUE if a cache image load is pending, and FALSE otherwise.
+ *
+ * Programmer:  John Mainzer, 1/10/17
+ *
+ * Changes:     None.
+ *
+ *-------------------------------------------------------------------------
+ */
+hbool_t
+H5AC_cache_image_pending(const H5F_t *f)
+{
+    H5C_t *cache_ptr;
+    hbool_t ret_value = FALSE;          /* Return value */
+
+    FUNC_ENTER_NOAPI_NOINIT_NOERR
+
+    /* Sanity checks */
+    HDassert(f);
+    HDassert(f->shared);
+    cache_ptr = f->shared->cache;
+
+    ret_value = H5C_cache_image_pending(cache_ptr);
+
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* H5AC_cache_image_pending() */
+
+
+/*-------------------------------------------------------------------------
  * Function:    H5AC_create
  *
  * Purpose:     Initialize the cache just after a file is opened.  The
@@ -835,6 +873,46 @@ done:
 
 
 /*-------------------------------------------------------------------------
+ * Function:    H5AC_force_cache_image_load()
+ *
+ * Purpose:     On rare occasions, it is necessary to run 
+ *              H5MF_tidy_self_referential_fsm_hack() prior to the first
+ *              metadata cache access.  This is a problem as if there is a 
+ *              cache image at the end of the file, that routine will 
+ *              discard it.
+ *
+ *              We solve this issue by calling this function, which will
+ *              load the cache image and then call 
+ *              H5MF_tidy_self_referential_fsm_hack() to discard it.
+ *
+ * Return:      SUCCEED on success, and FAIL on failure.
+ *
+ * Programmer:  John Mainzer
+ *              1/11/17
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5AC_force_cache_image_load(H5F_t *f, hid_t dxpl_id)
+{
+    herr_t ret_value = SUCCEED;      /* Return value */
+
+    FUNC_ENTER_NOAPI(FAIL)
+
+    /* Sanity checks */
+    HDassert(f);
+    HDassert(f->shared);
+    HDassert(f->shared->cache);
+
+    if(H5C_force_cache_image_load(f, dxpl_id) < 0)
+        HGOTO_ERROR(H5E_CACHE, H5E_CANTLOAD, FAIL, "Can't load cache image")
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* H5AC_force_cache_image_load() */
+
+
+/*-------------------------------------------------------------------------
  * Function:    H5AC_get_entry_status
  *
  * Purpose:     Given a file address, determine whether the metadata
@@ -3119,6 +3197,48 @@ done:
 
 
 /*-------------------------------------------------------------------------
+ * Function:    H5AC_unsettle_ring()
+ *
+ * Purpose:     Advise the metadata cache that the specified free space
+ *              manager ring is no longer settled (if it was on entry).
+ *
+ *              If the target free space manager ring is already
+ *              unsettled, do nothing, and return SUCCEED.
+ *
+ *              If the target free space manager ring is settled, and
+ *              we are not in the process of a file shutdown, mark
+ *              the ring as unsettled, and return SUCCEED.
+ *
+ *              If the target free space manager is settled, and we
+ *              are in the process of a file shutdown, post an error
+ *              message, and return FAIL.
+ *
+ *              Note that this function simply passes the call on to
+ *              the metadata cache proper, and returns the result.
+ *
+ * Return:      Non-negative on success/Negative on failure
+ *
+ * Programmer:  John Mainzer
+ *              10/15/16
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5AC_unsettle_ring(H5F_t * f, H5C_ring_t ring)
+{
+    herr_t              ret_value = SUCCEED;    /* Return value */
+
+    FUNC_ENTER_NOAPI(FAIL)
+
+    if(FAIL == (ret_value = H5C_unsettle_ring(f, ring)))
+        HGOTO_ERROR(H5E_CACHE, H5E_SYSTEM, FAIL, "H5C_unsettle_ring() failed")
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* H5AC_unsettle_ring() */
+
+
+/*-------------------------------------------------------------------------
  * Function:    H5AC_remove_entry()
  *
  * Purpose:     Remove an entry from the cache.  Must be not protected, pinned,
diff --git a/src/H5ACprivate.h b/src/H5ACprivate.h
index 1dc8270..1f8299b 100644
--- a/src/H5ACprivate.h
+++ b/src/H5ACprivate.h
@@ -451,6 +451,8 @@ H5_DLL herr_t H5AC_validate_config(H5AC_cache_config_t *config_ptr);
 H5_DLL herr_t H5AC_load_cache_image_on_next_protect(H5F_t *f, haddr_t addr, 
     hsize_t len, hbool_t rw);
 H5_DLL herr_t H5AC_validate_cache_image_config(H5AC_cache_image_config_t *config_ptr);
+H5_DLL hbool_t H5AC_cache_image_pending(const H5F_t *f);
+H5_DLL herr_t H5AC_force_cache_image_load(H5F_t * f, hid_t dxpl_id);
 
 /* Tag & Ring routines */
 H5_DLL herr_t H5AC_tag(hid_t dxpl_id, haddr_t metadata_tag, haddr_t *prev_tag);
@@ -464,6 +466,7 @@ H5_DLL herr_t H5AC_set_ring(hid_t dxpl_id, H5AC_ring_t ring, H5P_genplist_t **dx
     H5AC_ring_t *orig_ring);
 H5_DLL herr_t H5AC_reset_ring(H5P_genplist_t *dxpl, H5AC_ring_t orig_ring);
 H5_DLL herr_t H5AC_unsettle_entry_ring(void *entry);
+H5_DLL herr_t H5AC_unsettle_ring(H5F_t * f, H5AC_ring_t ring);
 H5_DLL herr_t H5AC_expunge_tag_type_metadata(H5F_t *f, hid_t dxpl_id, haddr_t tag, int type_id, unsigned flags);
 H5_DLL herr_t H5AC_get_tag(const void *thing, /*OUT*/ haddr_t *tag);
 
diff --git a/src/H5C.c b/src/H5C.c
index 1759292..120abb8 100644
--- a/src/H5C.c
+++ b/src/H5C.c
@@ -732,7 +732,8 @@ herr_t
 H5C_prep_for_file_close(H5F_t *f, hid_t dxpl_id)
 {
     H5C_t *     cache_ptr;
-    herr_t	ret_value = SUCCEED;      /* Return value */
+    hbool_t     image_generated = FALSE;        /* Whether a cache image was generated */
+    herr_t	ret_value = SUCCEED;            /* Return value */
 
     FUNC_ENTER_NOAPI(FAIL)
 
@@ -756,9 +757,48 @@ H5C_prep_for_file_close(H5F_t *f, hid_t dxpl_id)
     HDassert(cache_ptr->pl_len == 0);
 
     /* Prepare cache image */
-    if(H5C__prep_image_for_file_close(f, dxpl_id) < 0)
+    if(H5C__prep_image_for_file_close(f, dxpl_id, &image_generated) < 0)
         HGOTO_ERROR(H5E_CACHE, H5E_CANTCREATE, FAIL, "can't create cache image")
 
+#ifdef H5_HAVE_PARALLEL
+    if(!image_generated && cache_ptr->aux_ptr != NULL && f->shared->fs_persist) {
+        /* If persistent free space managers are enabled, flushing the
+         * metadata cache may result in the deletion, insertion, and/or
+         * dirtying of entries.
+         *
+         * This is a problem in PHDF5, as it breaks two invariants of
+         * our management of the metadata cache across all processes:
+         *
+         * 1) Entries will not be dirtied, deleted, inserted, or moved
+         *    during flush in the parallel case.
+         *
+         * 2) All processes contain the same set of dirty metadata
+         *    entries on entry to a sync point.
+         *
+         * To solve this problem for the persistent free space managers,
+         * serialize the metadata cache on all processes prior to the
+         * first sync point on file shutdown.  The shutdown warning is
+         * a convenient location for this call.
+         *
+         * This is sufficient since:
+         *
+         * 1) FSM settle routines are only invoked on file close.  Since
+         *    serialization make the same settle calls as flush on file
+         *    close, and since the close warning is issued after all
+         *    non FSM related space allocations and just before the
+         *    first sync point on close, this call will leave the caches
+         *    in a consistant state across the processes if they were
+         *    consistant before.
+         *
+         * 2) Since the FSM settle routines are only invoked once during
+         *    file close, invoking them now will prevent their invocation
+         *    during a flush, and thus avoid any resulting entrie dirties,
+         *    deletions, insertion, or moves during the flush.
+         */
+        if(H5C__serialize_cache(f, dxpl_id) < 0)
+            HGOTO_ERROR(H5E_CACHE, H5E_CANTSERIALIZE, FAIL, "serialization of the cache failed")
+    } /* end if */
+#endif /* H5_HAVE_PARALLEL */
 
 done:
     FUNC_LEAVE_NOAPI(ret_value)
@@ -3537,6 +3577,73 @@ done:
 
 
 /*-------------------------------------------------------------------------
+ * Function:    H5C_unsettle_ring()
+ *
+ * Purpose:     Advise the metadata cache that the specified free space
+ *              manager ring is no longer settled (if it was on entry).
+ *
+ *              If the target free space manager ring is already
+ *              unsettled, do nothing, and return SUCCEED.
+ *
+ *              If the target free space manager ring is settled, and
+ *              we are not in the process of a file shutdown, mark
+ *              the ring as unsettled, and return SUCCEED.
+ *
+ *              If the target free space manager is settled, and we
+ *              are in the process of a file shutdown, post an error
+ *              message, and return FAIL.
+ *
+ * Return:      Non-negative on success/Negative on failure
+ *
+ * Programmer:  John Mainzer
+ *              10/15/16
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5C_unsettle_ring(H5F_t * f, H5C_ring_t ring)
+{
+    H5C_t *             cache_ptr;
+    herr_t ret_value = SUCCEED; /* Return value */
+
+    FUNC_ENTER_NOAPI(FAIL)
+
+    /* Sanity checks */
+    HDassert(f);
+    HDassert(f->shared);
+    HDassert(f->shared->cache);
+    HDassert((H5C_RING_RDFSM == ring) || (H5C_RING_MDFSM == ring));
+    cache_ptr = f->shared->cache;
+    HDassert(H5C__H5C_T_MAGIC == cache_ptr->magic);
+
+    switch(ring) {
+        case H5C_RING_RDFSM:
+            if(cache_ptr->rdfsm_settled) {
+                if(cache_ptr->close_warning_received)
+                    HGOTO_ERROR(H5E_CACHE, H5E_SYSTEM, FAIL, "unexpected rdfsm ring unsettle")
+                cache_ptr->rdfsm_settled = FALSE;
+            } /* end if */
+            break;
+
+        case H5C_RING_MDFSM:
+            if(cache_ptr->mdfsm_settled) {
+                if(cache_ptr->close_warning_received)
+                    HGOTO_ERROR(H5E_CACHE, H5E_SYSTEM, FAIL, "unexpected mdfsm ring unsettle")
+                cache_ptr->mdfsm_settled = FALSE;
+            } /* end if */
+            break;
+
+	default:
+	    HDassert(FALSE); /* this should be un-reachable */
+	    break;
+    } /* end switch */
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* H5C_unsettle_ring() */
+
+
+/*-------------------------------------------------------------------------
  * Function:    H5C_validate_resize_config()
  *
  * Purpose:	Run a sanity check on the specified sections of the
@@ -6007,6 +6114,7 @@ H5C__flush_single_entry(H5F_t *f, hid_t dxpl_id, H5C_cache_entry_t *entry_ptr,
     hbool_t		write_entry;		/* internal flag */
     hbool_t		destroy_entry;		/* internal flag */
     hbool_t		generate_image;		/* internal flag */
+    hbool_t		update_page_buffer;	/* internal flag */
     hbool_t		was_dirty;
     hbool_t		suppress_image_entry_writes = FALSE;
     hbool_t		suppress_image_entry_frees = FALSE;
@@ -6032,6 +6140,7 @@ H5C__flush_single_entry(H5F_t *f, hid_t dxpl_id, H5C_cache_entry_t *entry_ptr,
     del_from_slist_on_destroy = ((flags & H5C__DEL_FROM_SLIST_ON_DESTROY_FLAG) != 0);
     during_flush           = ((flags & H5C__DURING_FLUSH_FLAG) != 0);
     generate_image         = ((flags & H5C__GENERATE_IMAGE_FLAG) != 0);
+    update_page_buffer     = ((flags & H5C__UPDATE_PAGE_BUFFER_FLAG) != 0);
 
     /* Set the flag for destroying the entry, based on the 'take ownership'
      * and 'destroy' flags
@@ -6447,6 +6556,19 @@ H5C__flush_single_entry(H5F_t *f, hid_t dxpl_id, H5C_cache_entry_t *entry_ptr,
         } /* end else */
     } /* if (destroy) */
 
+    /* Check if we have to update the page buffer with cleared entries 
+     * so it doesn't go out of date 
+     */
+    if(update_page_buffer) {
+        /* Sanity check */
+        HDassert(!destroy);
+        HDassert(entry_ptr->image_ptr);
+
+        if(f->shared->page_buf && f->shared->page_buf->page_size >= entry_ptr->size)
+            if(H5PB_update_entry(f->shared->page_buf, entry_ptr->addr, entry_ptr->size, entry_ptr->image_ptr) > 0)
+                HGOTO_ERROR(H5E_CACHE, H5E_SYSTEM, FAIL, "Failed to update PB with metadata cache")
+    } /* end if */
+
     if(cache_ptr->log_flush)
         if((cache_ptr->log_flush)(cache_ptr, entry_addr, was_dirty, flags) < 0)
             HGOTO_ERROR(H5E_CACHE, H5E_CANTFLUSH, FAIL, "log_flush callback failed")
diff --git a/src/H5Cimage.c b/src/H5Cimage.c
index 3a21137..fc58dac 100644
--- a/src/H5Cimage.c
+++ b/src/H5Cimage.c
@@ -147,6 +147,40 @@ H5FL_DEFINE(H5C_cache_entry_t);
 
 
 /*-------------------------------------------------------------------------
+ *
+ * Function:    H5C_cache_image_pending()
+ *
+ * Purpose:     Tests to see if the load of a metadata cache image 
+ *              load is pending (i.e. will be executed on the next 
+ *              protect or insert)
+ *
+ *              Returns TRUE if a cache image load is pending, and FALSE
+ *              if not.  Throws an assertion failure on error.
+ *
+ * Return:      TRUE if a cache image load is pending, and FALSE otherwise.
+ *
+ * Programmer:  John Mainzer, 6/18/16
+ *
+ *-------------------------------------------------------------------------
+ */
+hbool_t
+H5C_cache_image_pending(const H5C_t *cache_ptr)
+{
+    hbool_t             ret_value = TRUE;      /* Return value */
+
+    FUNC_ENTER_NOAPI_NOINIT_NOERR
+
+    /* Sanity checks */
+    HDassert(cache_ptr);
+    HDassert(cache_ptr->magic == H5C__H5C_T_MAGIC);
+
+    ret_value = (cache_ptr->load_image && !cache_ptr->image_loaded);
+
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* H5C_cache_image_pending() */
+
+
+/*-------------------------------------------------------------------------
  * Function:    H5C_cache_image_status()
  *
  * Purpose:     Examine the metadata cache associated with the supplied 
@@ -832,6 +866,54 @@ H5C__free_image_entries_array(H5C_t * cache_ptr)
 
 
 /*-------------------------------------------------------------------------
+ * Function:    H5C_force_cache_image_load()
+ *
+ * Purpose:     On rare occasions, it is necessary to run 
+ *		H5MF_tidy_self_referential_fsm_hack() prior to the first
+ *              metadata cache access.  This is a problem as if there is a 
+ *              cache image at the end of the file, that routine will 
+ *              discard it.
+ *
+ *              We solve this issue by calling this function, which will
+ *		load the cache image and then call 
+ *              H5MF_tidy_self_referential_fsm_hack() to discard it.
+ *
+ * Return:      SUCCEED on success, and FAIL on failure.
+ *
+ * Programmer:  John Mainzer
+ *              1/11/17
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5C_force_cache_image_load(H5F_t *f, hid_t dxpl_id)
+{
+    H5C_t *cache_ptr;
+    herr_t ret_value = SUCCEED;      /* Return value */
+
+    FUNC_ENTER_NOAPI(FAIL)
+
+    /* Sanity checks */
+    HDassert(f);
+    HDassert(f->shared);
+    cache_ptr = f->shared->cache;
+    HDassert(cache_ptr);
+    HDassert(cache_ptr->magic == H5C__H5C_T_MAGIC);
+    HDassert(cache_ptr->load_image);
+
+    /* Load the cache image, if requested */
+    if(cache_ptr->load_image) {
+        cache_ptr->load_image = FALSE;
+        if(H5C__load_cache_image(f, dxpl_id) < 0)
+            HGOTO_ERROR(H5E_CACHE, H5E_CANTLOAD, FAIL, "can't load cache image")
+    } /* end if */
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* H5C_force_cache_image_load() */
+
+
+/*-------------------------------------------------------------------------
  * Function:    H5C_get_cache_image_config
  *
  * Purpose:     Copy the current configuration for cache image generation
@@ -1239,7 +1321,7 @@ H5C__image_entry_cmp(const void *_entry1, const void *_entry2)
  *-------------------------------------------------------------------------
  */
 herr_t
-H5C__prep_image_for_file_close(H5F_t *f, hid_t dxpl_id)
+H5C__prep_image_for_file_close(H5F_t *f, hid_t dxpl_id, hbool_t *image_generated)
 {
     H5C_t *     cache_ptr = NULL;
     haddr_t     eoa_frag_addr = HADDR_UNDEF;
@@ -1255,6 +1337,7 @@ H5C__prep_image_for_file_close(H5F_t *f, hid_t dxpl_id)
     cache_ptr = f->shared->cache;
     HDassert(cache_ptr);
     HDassert(cache_ptr->magic == H5C__H5C_T_MAGIC);
+    HDassert(image_generated);
 
     /* If the file is opened and closed without any access to 
      * any group or data set, it is possible that the cache image (if 
@@ -1379,6 +1462,15 @@ H5C__prep_image_for_file_close(H5F_t *f, hid_t dxpl_id)
                         (hsize_t)(cache_ptr->image_data_len), &eoa_frag_addr, &eoa_frag_size)))
                 HGOTO_ERROR(H5E_CACHE, H5E_NOSPACE, FAIL, "can't allocate file space for metadata cache image")
 
+        /* Make note of the eoa after allocation of the cache image
+         * block.  This value is used for sanity checking when we
+         * shutdown the self referential free space managers after
+         * we destroy the metadata cache.
+         */
+        HDassert(HADDR_UNDEF == f->shared->eoa_post_mdci_fsalloc);
+        if(HADDR_UNDEF == (f->shared->eoa_post_mdci_fsalloc = H5FD_get_eoa(f->shared->lf, H5FD_MEM_DEFAULT)) )
+            HGOTO_ERROR(H5E_FILE, H5E_CANTGET, FAIL, "unable to get file size")
+
         /* For now, drop any fragment left over from the allocation of the
          * image block on the ground.  A fragment should only be returned
          * if the underlying file alignment is greater than 1.
@@ -1468,6 +1560,9 @@ H5C__prep_image_for_file_close(H5F_t *f, hid_t dxpl_id)
 
             cache_ptr->image_ctl.generate_image = FALSE;
         } /* end else */
+
+        /* Indicate that a cache image was generated */
+        *image_generated = TRUE;
     } /* end if */
 
 done:
diff --git a/src/H5Cmpio.c b/src/H5Cmpio.c
index 1f43866..06ce714 100644
--- a/src/H5Cmpio.c
+++ b/src/H5Cmpio.c
@@ -791,7 +791,7 @@ H5C_mark_entries_as_clean(H5F_t *  f,
             entries_cleared++;
 
             if(H5C__flush_single_entry(f, dxpl_id, clear_ptr,
-                    (H5C__FLUSH_CLEAR_ONLY_FLAG | H5C__GENERATE_IMAGE_FLAG)) < 0)
+                    (H5C__FLUSH_CLEAR_ONLY_FLAG | H5C__GENERATE_IMAGE_FLAG | H5C__UPDATE_PAGE_BUFFER_FLAG)) < 0)
                 HGOTO_ERROR(H5E_CACHE, H5E_CANTFLUSH, FAIL, "can't clear entry")
         } /* end if */
         else
@@ -821,7 +821,7 @@ H5C_mark_entries_as_clean(H5F_t *  f,
                 progress = TRUE;
 
                 if(H5C__flush_single_entry(f, dxpl_id, clear_ptr, 
-                        (H5C__FLUSH_CLEAR_ONLY_FLAG | H5C__GENERATE_IMAGE_FLAG)) < 0)
+                        (H5C__FLUSH_CLEAR_ONLY_FLAG | H5C__GENERATE_IMAGE_FLAG | H5C__UPDATE_PAGE_BUFFER_FLAG)) < 0)
                     HGOTO_ERROR(H5E_CACHE, H5E_CANTFLUSH, FAIL, "can't clear entry")
             } /* end if */
             else
@@ -1242,7 +1242,8 @@ H5C__flush_candidates_in_ring(H5F_t *f, hid_t dxpl_id, H5C_ring_t ring,
     unsigned  init_index_len;
 #endif /* H5C_DO_SANITY_CHECKS */
     unsigned  clear_flags = H5C__FLUSH_CLEAR_ONLY_FLAG |
-                            H5C__GENERATE_IMAGE_FLAG;
+                            H5C__GENERATE_IMAGE_FLAG |
+                            H5C__UPDATE_PAGE_BUFFER_FLAG;
     unsigned  flush_flags = H5C__NO_FLAGS_SET;
     unsigned  op_flags;
     H5C_cache_entry_t *op_ptr;
diff --git a/src/H5Cpkg.h b/src/H5Cpkg.h
index 321f1fb..69e8145 100644
--- a/src/H5Cpkg.h
+++ b/src/H5Cpkg.h
@@ -4901,7 +4901,8 @@ typedef int (*H5C_tag_iter_cb_t)(H5C_cache_entry_t *entry, void *ctx);
 /******************************/
 /* Package Private Prototypes */
 /******************************/
-H5_DLL herr_t H5C__prep_image_for_file_close(H5F_t *f, hid_t dxpl_id);
+H5_DLL herr_t H5C__prep_image_for_file_close(H5F_t *f, hid_t dxpl_id,
+    hbool_t *image_generated);
 H5_DLL herr_t H5C__deserialize_prefetched_entry(H5F_t *f, hid_t dxpl_id,
     H5C_t * cache_ptr, H5C_cache_entry_t** entry_ptr_ptr, 
     const H5C_class_t * type, haddr_t addr, void * udata);
diff --git a/src/H5Cprivate.h b/src/H5Cprivate.h
index 3408839..539dece 100644
--- a/src/H5Cprivate.h
+++ b/src/H5Cprivate.h
@@ -185,6 +185,7 @@
  *      H5C__TAKE_OWNERSHIP_FLAG
  *      H5C__DEL_FROM_SLIST_ON_DESTROY_FLAG
  *      H5C__GENERATE_IMAGE_FLAG
+ *      H5C__UPDATE_PAGE_BUFFER_FLAG
  */
 #define H5C__NO_FLAGS_SET			0x00000
 #define H5C__SET_FLUSH_MARKER_FLAG		0x00001
@@ -205,6 +206,7 @@
 #define H5C__DEL_FROM_SLIST_ON_DESTROY_FLAG     0x08000
 #define H5C__DURING_FLUSH_FLAG                  0x10000 /* Set when the entire cache is being flushed */
 #define H5C__GENERATE_IMAGE_FLAG                0x20000 /* Set during parallel I/O */
+#define H5C__UPDATE_PAGE_BUFFER_FLAG            0x40000 /* Set during parallel I/O */
 
 /* Debugging/sanity checking/statistics settings */
 #ifndef NDEBUG
@@ -2249,6 +2251,7 @@ 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 dxpl_id, unsigned flags);
 H5_DLL herr_t H5C_flush_tagged_entries(H5F_t * f, hid_t dxpl_id, haddr_t tag); 
+H5_DLL herr_t H5C_force_cache_image_load(H5F_t * f, hid_t dxpl_id);
 H5_DLL herr_t H5C_evict_tagged_entries(H5F_t * f, hid_t dxpl_id, haddr_t tag, hbool_t match_global);
 H5_DLL herr_t H5C_expunge_tag_type_metadata(H5F_t *f, hid_t dxpl_id, haddr_t tag, int type_id, unsigned flags);
 H5_DLL herr_t H5C_get_tag(const void *thing, /*OUT*/ haddr_t *tag);
@@ -2313,9 +2316,11 @@ H5_DLL herr_t H5C_retag_entries(H5C_t * cache_ptr, haddr_t src_tag, haddr_t dest
 H5_DLL herr_t H5C_cork(H5C_t *cache_ptr, haddr_t obj_addr, unsigned action, hbool_t *corked);
 H5_DLL herr_t H5C_get_entry_ring(const H5F_t *f, haddr_t addr, H5C_ring_t *ring);
 H5_DLL herr_t H5C_unsettle_entry_ring(void *thing);
+H5_DLL herr_t H5C_unsettle_ring(H5F_t * f, H5C_ring_t ring);
 H5_DLL herr_t H5C_remove_entry(void *thing);
 H5_DLL herr_t H5C_cache_image_status(H5F_t * f, hbool_t *load_ci_ptr, 
     hbool_t *write_ci_ptr);
+H5_DLL hbool_t H5C_cache_image_pending(const H5C_t *cache_ptr);
 
 #ifdef H5_HAVE_PARALLEL
 H5_DLL herr_t H5C_apply_candidate_list(H5F_t *f, hid_t dxpl_id,
diff --git a/src/H5F.c b/src/H5F.c
index 431b56f..a0f7599 100644
--- a/src/H5F.c
+++ b/src/H5F.c
@@ -1975,7 +1975,9 @@ H5Fformat_convert(hid_t fid)
 
         /* Check for persistent freespace manager, which needs to be downgraded */
         if(!(f->shared->fs_strategy == H5F_FILE_SPACE_STRATEGY_DEF &&
-                f->shared->fs_threshold == H5F_FREE_SPACE_THRESHOLD_DEF)) {
+             f->shared->fs_persist == H5F_FREE_SPACE_PERSIST_DEF &&
+             f->shared->fs_threshold == H5F_FREE_SPACE_THRESHOLD_DEF &&
+             f->shared->fs_page_size == H5F_FILE_SPACE_PAGE_SIZE_DEF)) {
             /* Check to remove free-space manager info message from superblock extension */
             if(H5F_addr_defined(f->shared->sblock->ext_addr))
                 if(H5F_super_ext_remove_msg(f, H5AC_ind_read_dxpl_id, H5O_FSINFO_ID) < 0)
@@ -1987,7 +1989,9 @@ H5Fformat_convert(hid_t fid)
 
             /* Set non-persistent freespace manager */
             f->shared->fs_strategy = H5F_FILE_SPACE_STRATEGY_DEF;
+            f->shared->fs_persist = H5F_FREE_SPACE_PERSIST_DEF;
             f->shared->fs_threshold = H5F_FREE_SPACE_THRESHOLD_DEF;
+            f->shared->fs_page_size = H5F_FILE_SPACE_PAGE_SIZE_DEF;
 
             /* Indicate that the superblock should be marked dirty */
             mark_dirty = TRUE;
@@ -2006,3 +2010,79 @@ done:
     FUNC_LEAVE_API(ret_value)
 } /* end H5Fformat_convert() */
 
+
+/*-------------------------------------------------------------------------
+ * Function:    H5Freset_page_buffering_stats
+ *
+ * Purpose:     Resets statistics for the page buffer layer.
+ *
+ * Return:      Success:        SUCCEED
+ *              Failure:        FAIL
+ *
+ * Programmer:  Mohamad Chaarawi
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5Freset_page_buffering_stats(hid_t file_id)
+{
+    H5F_t   *file;                      /* File to reset stats on */
+    herr_t ret_value = SUCCEED;         /* Return value */
+
+    FUNC_ENTER_API(FAIL)
+    H5TRACE1("e", "i", file_id);
+
+    /* Check args */
+    if(NULL == (file = (H5F_t *)H5I_object(file_id)))
+        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "invalid file identifier")
+    if(NULL == file->shared->page_buf)
+        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "page buffering not enabled on file")
+
+    /* Reset the statistics */
+    if(H5PB_reset_stats(file->shared->page_buf) < 0)
+        HGOTO_ERROR(H5E_FILE, H5E_CANTGET, FAIL, "can't reset stats for page buffering")
+
+done:
+    FUNC_LEAVE_API(ret_value)
+}   /* H5Freset_page_buffering_stats() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:    H5Fget_page_buffering_stats
+ *
+ * Purpose:     Retrieves statistics for the page buffer layer.
+ *
+ * Return:      Success:        SUCCEED
+ *              Failure:        FAIL
+ *
+ * Programmer:  Mohamad Chaarawi
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5Fget_page_buffering_stats(hid_t file_id, unsigned accesses[2], unsigned hits[2],
+    unsigned misses[2], unsigned evictions[2], unsigned bypasses[2])
+{
+    H5F_t      *file;                   /* File object for file ID */
+    herr_t     ret_value = SUCCEED;     /* Return value */
+
+    FUNC_ENTER_API(FAIL)
+    H5TRACE6("e", "i*Iu*Iu*Iu*Iu*Iu", file_id, accesses, hits, misses, evictions,
+             bypasses);
+
+    /* Check args */
+    if(NULL == (file = (H5F_t *)H5I_object_verify(file_id, H5I_FILE)))
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "not a file ID")
+    if(NULL == file->shared->page_buf)
+        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "page buffering not enabled on file")
+    if(NULL == accesses || NULL == hits || NULL == misses || NULL == evictions || NULL == bypasses)
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "NULL input parameters for stats")
+
+    /* Get the statistics */
+    if(H5PB_get_stats(file->shared->page_buf, accesses, hits, misses, evictions, bypasses) < 0)
+        HGOTO_ERROR(H5E_FILE, H5E_CANTGET, FAIL, "can't retrieve stats for page buffering")
+
+done:
+    FUNC_LEAVE_API(ret_value)
+} /* H5Fget_page_buffering_stats() */
+
diff --git a/src/H5FD.c b/src/H5FD.c
index db8c09c..96d1230 100644
--- a/src/H5FD.c
+++ b/src/H5FD.c
@@ -2054,3 +2054,27 @@ H5FD_get_base_addr(const H5FD_t *file)
     FUNC_LEAVE_NOAPI(file->base_addr)
 } /* end H5FD_get_base_addr() */
 
+
+/*--------------------------------------------------------------------------
+ * Function:    H5FD_set_paged_aggr
+ *
+ * Purpose:     Set "paged_aggr" for the file.
+ *
+ * Return:      Non-negative if succeed; negative if fails.
+ *
+ * Programmer:  Vailin Choi; April 2013
+ *
+ *--------------------------------------------------------------------------
+ */
+herr_t
+H5FD_set_paged_aggr(H5FD_t *file, hbool_t paged)
+{
+    FUNC_ENTER_NOAPI_NOINIT_NOERR
+
+    HDassert(file);
+
+    /* Indicate whether paged aggregation for handling file space is enabled or not */
+    file->paged_aggr = paged;
+
+    FUNC_LEAVE_NOAPI(SUCCEED)
+} /* end H5FD_set_paged_aggr() */
diff --git a/src/H5FDlog.c b/src/H5FDlog.c
index 03228d2..f320946 100644
--- a/src/H5FDlog.c
+++ b/src/H5FDlog.c
@@ -934,13 +934,7 @@ H5FD_log_alloc(H5FD_t *_file, H5FD_mem_t type, hid_t H5_ATTR_UNUSED dxpl_id, hsi
     /* Compute the address for the block to allocate */
     addr = file->eoa;
 
-    /* Check if we need to align this block */
-    if(size >= file->pub.threshold) {
-        /* Check for an already aligned block */
-        if(addr % file->pub.alignment != 0)
-            addr = ((addr / file->pub.alignment) + 1) * file->pub.alignment;
-    } /* end if */
-
+    /* Extend the end-of-allocated space address */
     file->eoa = addr + size;
 
     /* Retain the (first) flavor of the information written to the file */
diff --git a/src/H5FDmulti.c b/src/H5FDmulti.c
index 7e12869..0ab7fc5 100644
--- a/src/H5FDmulti.c
+++ b/src/H5FDmulti.c
@@ -1194,6 +1194,8 @@ H5FD_multi_query(const H5FD_t *_f, unsigned long *flags /* out */)
         *flags = 0;
         *flags |= H5FD_FEAT_DATA_SIEVE;             /* OK to perform data sieving for faster raw data reads & writes */
         *flags |= H5FD_FEAT_AGGREGATE_SMALLDATA;    /* OK to aggregate "small" raw data allocations */
+        *flags |= H5FD_FEAT_USE_ALLOC_SIZE;     /* OK just pass the allocation size to the alloc callback */
+        *flags |= H5FD_FEAT_PAGED_AGGR;         /* OK special file space mapping for paged aggregation */
     } /* end if */
 
     return(0);
@@ -1538,6 +1540,14 @@ H5FD_multi_alloc(H5FD_t *_file, H5FD_mem_t type, hid_t dxpl_id, hsize_t size)
     mmt = file->fa.memb_map[type];
     if (H5FD_MEM_DEFAULT==mmt) mmt = type;
 
+    /* XXX: NEED to work on this again */
+    if(file->pub.paged_aggr) {
+        ALL_MEMBERS(mt) {
+            if(file->memb[mt])
+                file->memb[mt]->paged_aggr = file->pub.paged_aggr;
+        } END_MEMBERS;
+    }
+
     if (HADDR_UNDEF==(addr=H5FDalloc(file->memb[mmt], mmt, dxpl_id, size)))
         H5Epush_ret(func, H5E_ERR_CLS, H5E_INTERNAL, H5E_BADVALUE, "member file can't alloc", HADDR_UNDEF)
     addr += file->fa.memb_addr[mmt];
diff --git a/src/H5FDprivate.h b/src/H5FDprivate.h
index 0e2928d..c64ec30 100644
--- a/src/H5FDprivate.h
+++ b/src/H5FDprivate.h
@@ -154,8 +154,8 @@ H5_DLL H5FD_t *H5FD_open(const char *name, unsigned flags, hid_t fapl_id,
 		  haddr_t maxaddr);
 H5_DLL herr_t H5FD_close(H5FD_t *file);
 H5_DLL int H5FD_cmp(const H5FD_t *f1, const H5FD_t *f2);
-H5_DLL haddr_t H5FD_alloc(H5FD_t *file, hid_t dxpl_id, H5FD_mem_t type, struct H5F_t *f,
-    hsize_t size, haddr_t *align_addr, hsize_t *align_size);
+H5_DLL haddr_t H5FD_alloc(H5FD_t *file, hid_t dxpl_id, H5FD_mem_t type, 
+    struct H5F_t *f, hsize_t size, haddr_t *frag_addr, hsize_t *frag_size);
 H5_DLL herr_t H5FD_free(H5FD_t *file, hid_t dxpl_id, H5FD_mem_t type, struct H5F_t *f,
     haddr_t addr, hsize_t size);
 H5_DLL htri_t H5FD_try_extend(H5FD_t *file, H5FD_mem_t type, struct H5F_t *f,
@@ -179,6 +179,7 @@ H5_DLL herr_t H5FD_get_fileno(const H5FD_t *file, unsigned long *filenum);
 H5_DLL herr_t H5FD_get_vfd_handle(H5FD_t *file, hid_t fapl, void** file_handle);
 H5_DLL herr_t H5FD_set_base_addr(H5FD_t *file, haddr_t base_addr);
 H5_DLL haddr_t H5FD_get_base_addr(const H5FD_t *file);
+H5_DLL herr_t H5FD_set_paged_aggr(H5FD_t *file, hbool_t paged);
 
 /* Function prototypes for MPI based VFDs*/
 #ifdef H5_HAVE_PARALLEL
diff --git a/src/H5FDpublic.h b/src/H5FDpublic.h
index 436be10..883b28d 100644
--- a/src/H5FDpublic.h
+++ b/src/H5FDpublic.h
@@ -239,6 +239,19 @@ typedef enum H5F_mem_t	H5FD_mem_t;
      * driver supports the single-writer/multiple-readers I/O pattern.
      */
 #define H5FD_FEAT_SUPPORTS_SWMR_IO      0x00001000
+    /*
+     * Defining H5FD_FEAT_USE_ALLOC_SIZE for a VFL driver
+     * means that the library will just pass the allocation size to the
+     * the driver's allocation callback which will eventually handle alignment.
+     * This is specifically used for the multi/split driver.
+     */
+#define H5FD_FEAT_USE_ALLOC_SIZE	0x00002000
+    /*
+     * Defining H5FD_FEAT_PAGED_AGGR for a VFL driver
+     * means that the driver needs special file space mapping for paged aggregation.
+     * This is specifically used for the multi/split driver.
+     */
+#define H5FD_FEAT_PAGED_AGGR		0x00004000
 
 /* Forward declaration */
 typedef struct H5FD_t H5FD_t;
@@ -307,6 +320,7 @@ struct H5FD_t {
     /* Space allocation management fields */
     hsize_t             threshold;      /* Threshold for alignment  */
     hsize_t             alignment;      /* Allocation alignment     */
+    hbool_t             paged_aggr;     /* Paged aggregation for file space is enabled or not */
 };
 
 /* Define enum for the source of file image callbacks */
diff --git a/src/H5FDspace.c b/src/H5FDspace.c
index fcddecf..0ad3cf0 100644
--- a/src/H5FDspace.c
+++ b/src/H5FDspace.c
@@ -99,7 +99,7 @@ H5FL_DEFINE(H5FD_free_t);
  *-------------------------------------------------------------------------
  */
 static haddr_t
-H5FD_extend(H5FD_t *file, H5FD_mem_t type, hbool_t new_block, hsize_t size, haddr_t *frag_addr, hsize_t *frag_size)
+H5FD_extend(H5FD_t *file, H5FD_mem_t type, hsize_t size)
 {
     hsize_t orig_size = size;   /* Original allocation size */
     haddr_t eoa;                /* Address of end-of-allocated space */
@@ -117,40 +117,18 @@ H5FD_extend(H5FD_t *file, H5FD_mem_t type, hbool_t new_block, hsize_t size, hadd
     /* Get current end-of-allocated space address */
     eoa = file->cls->get_eoa(file, type);
 
-    /* Compute extra space to allocate, if this is a new block and should be aligned */
-    extra = 0;
-    if(new_block && file->alignment > 1 && orig_size >= file->threshold) {
-        hsize_t mis_align;              /* Amount EOA is misaligned */
-
-        /* Check for EOA already aligned */
-        if((mis_align = (eoa % file->alignment)) > 0) {
-            extra = file->alignment - mis_align;
-	    if(frag_addr)
-                *frag_addr = eoa - file->base_addr;     /* adjust for file's base address */
-	    if(frag_size)
-                *frag_size = extra;
-	} /* end if */
-    } /* end if */
-
-    /* Add in extra allocation amount */
-    size += extra;
-
     /* Check for overflow when extending */
     if(H5F_addr_overflow(eoa, size) || (eoa + size) > file->maxaddr)
         HGOTO_ERROR(H5E_VFL, H5E_NOSPACE, HADDR_UNDEF, "file allocation request failed")
 
-    /* Set the [possibly aligned] address to return */
-    ret_value = eoa + extra;
+    /* Set the [NOT aligned] address to return */
+    ret_value = eoa;
 
     /* Extend the end-of-allocated space address */
     eoa += size;
     if(file->cls->set_eoa(file, type, eoa) < 0)
         HGOTO_ERROR(H5E_VFL, H5E_NOSPACE, HADDR_UNDEF, "file allocation request failed")
 
-    /* Post-condition sanity check */
-    if(new_block && file->alignment && orig_size >= file->threshold)
-	HDassert(!(ret_value % file->alignment));
-
 done:
     FUNC_LEAVE_NOAPI(ret_value)
 } /* end H5FD_extend() */
@@ -160,6 +138,8 @@ done:
  * Function:    H5FD_alloc_real
  *
  * Purpose:     Allocate space in the file with the VFD
+ *              Note: the handling of alignment is moved up from each driver to
+ *              this routine.
  *
  * Return:      Success:    The format address of the new file memory.
  *              Failure:    The undefined address HADDR_UNDEF
@@ -170,8 +150,14 @@ done:
  *-------------------------------------------------------------------------
  */
 haddr_t
-H5FD_alloc_real(H5FD_t *file, hid_t dxpl_id, H5FD_mem_t type, hsize_t size, haddr_t *frag_addr, hsize_t *frag_size)
+H5FD_alloc_real(H5FD_t *file, hid_t dxpl_id, H5FD_mem_t type, hsize_t size, 
+    haddr_t *frag_addr, hsize_t *frag_size)
 {
+    hsize_t orig_size = size;   /* Original allocation size */
+    haddr_t eoa;                /* Address of end-of-allocated space */
+    hsize_t extra;              /* Extra space to allocate, to align request */
+    unsigned long flags = 0;    /* Driver feature flags */
+    hbool_t use_alloc_size;     /* Just pass alloc size to the driver */
     haddr_t ret_value = HADDR_UNDEF;    /* Return value */
 
     FUNC_ENTER_NOAPI(HADDR_UNDEF)
@@ -185,16 +171,53 @@ HDfprintf(stderr, "%s: type = %u, size = %Hu\n", FUNC, (unsigned)type, size);
     HDassert(type >= H5FD_MEM_DEFAULT && type < H5FD_MEM_NTYPES);
     HDassert(size > 0);
 
+    /* Check for query driver and call it */
+    if(file->cls->query)
+        (file->cls->query)(file, &flags);
+
+    /* Check for the driver feature flag */
+    use_alloc_size = flags & H5FD_FEAT_USE_ALLOC_SIZE;
+
+    /* Get current end-of-allocated space address */
+    eoa = file->cls->get_eoa(file, type);
+
+    /* Compute extra space to allocate, if this should be aligned */
+    extra = 0;
+    if(!file->paged_aggr && file->alignment > 1 && orig_size >= file->threshold) {
+        hsize_t mis_align;              /* Amount EOA is misaligned */
+
+        /* Check for EOA already aligned */
+        if((mis_align = (eoa % file->alignment)) > 0) {
+            extra = file->alignment - mis_align;
+            if(frag_addr)
+                *frag_addr = eoa - file->base_addr;     /* adjust for file's base address */
+            if(frag_size)
+                *frag_size = extra;
+        } /* end if */
+    } /* end if */
+
     /* Dispatch to driver `alloc' callback or extend the end-of-address marker */
+    /* For the multi/split driver: the size passed down to the alloc callback is the original size from H5FD_alloc() */
+    /* For all other drivers: the size passed down to the alloc callback is the size + [possibly] alignment size */
     if(file->cls->alloc) {
-        if((ret_value = (file->cls->alloc)(file, type, dxpl_id, size)) == HADDR_UNDEF)
+        ret_value = (file->cls->alloc)(file, type, dxpl_id, use_alloc_size ? size : size + extra);
+        if(!H5F_addr_defined(ret_value))
             HGOTO_ERROR(H5E_VFL, H5E_NOSPACE, HADDR_UNDEF, "driver allocation request failed")
     } /* end if */
     else {
-        if((ret_value = H5FD_extend(file, type, TRUE, size, frag_addr, frag_size)) == HADDR_UNDEF)
+        ret_value = H5FD_extend(file, type, size + extra);
+        if(!H5F_addr_defined(ret_value))
             HGOTO_ERROR(H5E_VFL, H5E_NOSPACE, HADDR_UNDEF, "driver eoa update request failed")
     } /* end else */
 
+    /* Set the [possibly aligned] address to return */
+    if(!use_alloc_size)
+        ret_value += extra;
+
+    /* Post-condition sanity check */
+    if(!file->paged_aggr && file->alignment > 1 && orig_size >= file->threshold)
+        HDassert(!(ret_value % file->alignment));
+
     /* Convert absolute file offset to relative address */
     ret_value -= file->base_addr;
 
@@ -420,7 +443,7 @@ H5FD_try_extend(H5FD_t *file, H5FD_mem_t type, H5F_t *f, hid_t dxpl_id,
     /* Check if the block is exactly at the end of the file */
     if(H5F_addr_eq(blk_end, eoa)) {
         /* Extend the object by extending the underlying file */
-        if(HADDR_UNDEF == H5FD_extend(file, type, FALSE, extra_requested, NULL, NULL))
+        if(HADDR_UNDEF == H5FD_extend(file, type, extra_requested))
             HGOTO_ERROR(H5E_VFL, H5E_CANTEXTEND, FAIL, "driver extend request failed")
 
         /* Mark EOA info dirty in cache, so change will get encoded */
diff --git a/src/H5FDstdio.c b/src/H5FDstdio.c
index 4c62bcc..13f728e 100644
--- a/src/H5FDstdio.c
+++ b/src/H5FDstdio.c
@@ -601,13 +601,6 @@ H5FD_stdio_alloc(H5FD_t *_file, H5FD_mem_t /*UNUSED*/ type, hid_t /*UNUSED*/ dxp
     /* Compute the address for the block to allocate */
     addr = file->eoa;
 
-    /* Check if we need to align this block */
-    if(size >= file->pub.threshold) {
-        /* Check for an already aligned block */
-        if((addr % file->pub.alignment) != 0)
-            addr = ((addr / file->pub.alignment) + 1) * file->pub.alignment;
-    } /* end if */
-
     file->eoa = addr + size;
 
     return addr;
diff --git a/src/H5FS.c b/src/H5FS.c
index 8644a6f..a433fbb 100644
--- a/src/H5FS.c
+++ b/src/H5FS.c
@@ -135,7 +135,7 @@ HDfprintf(stderr, "%s: Creating free space manager, nclasses = %Zu\n", FUNC, ncl
     fspace->swmr_write = (H5F_INTENT(f) & H5F_ACC_SWMR_WRITE) > 0;
 
     fspace->alignment = alignment;
-    fspace->threshold = threshold;
+    fspace->align_thres = threshold;
 
     /* Check if the free space tracker is supposed to be persistant */
     if(fs_addr) {
@@ -227,7 +227,7 @@ HDfprintf(stderr, "%s: fspace->rc = %u\n", FUNC, fspace->rc);
         HGOTO_ERROR(H5E_FSPACE, H5E_CANTINC, NULL, "unable to increment ref. count on free space header")
 
     fspace->alignment = alignment;
-    fspace->threshold = threshold;
+    fspace->align_thres = threshold;
 
     /* Unlock free space header */
     if(H5AC_unprotect(f, dxpl_id, H5AC_FSPACE_HDR, fs_addr, fspace, H5AC__NO_FLAGS_SET) < 0)
@@ -873,10 +873,7 @@ H5FS_alloc_sect(H5F_t *f, H5FS_t *fspace, hid_t dxpl_id)
     HDassert(fspace);
 
     if(!H5F_addr_defined(fspace->sect_addr) && fspace->sinfo && fspace->serial_sect_count > 0) {
-        /* Allocate space for section info from aggregator/vfd (or temp. address space) */
-        /* (The original version called H5MF_alloc(), but that may cause sect_size to change again) */
-        /* (This routine is only called during file close operations, so don't allocate from temp. address space) */
-        if(HADDR_UNDEF == (fspace->sect_addr = H5MF_aggr_vfd_alloc(f, H5FD_MEM_FSPACE_SINFO, dxpl_id, fspace->sect_size)))
+        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 section info")
         fspace->alloc_sect_size = fspace->sect_size;
 
@@ -901,169 +898,6 @@ done:
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5FS_alloc_vfd_alloc_hdr_and_section_info
- *
- * Purpose:	This function is part of a hack to patch over a design
- *              flaw in the free space managers for file space allocation.  
- *		Specifically, if a free space manager allocates space for 
- *		its own section info, it is possible for it to 
- *		go into an infinite loop as it:
- *
- *                      1) computes the size of the section info
- *
- *                      2) allocates file space for the section info
- *
- *                      3) notices that the size of the section info
- *                         has changed
- *
- *                      4) deallocates the section info file space and
- *                         returns to 1) above.
- *
- *		Similarly, if it allocates space for its own header, it 
- *		can go into an infinte loop as it:
- *
- *			1) allocates space for the header
- *
- *			2) notices that the free space manager is empty
- *			   and thus should not have file space allocated 
- *			   to its header
- *
- *			3) frees the space allocated to the header
- *
- *			4) notices that the free space manager is not 
- *			   empty and thus must have file space allocated
- *			   to it, and thus returns to 1) above.
- *
- *              In a nutshell, the solution applied in this hack is to
- *		deallocate file space for the free space manager(s) that
- *		handle FSM header and/or section info file space allocations,
- *              wait until all other allocation/deallocation requests have
- *              been handled, and then test to see if the free space manager(s)
- *		in question are empty.  If they are, do nothing.  If they 
- *		are not, allocate space for them at end of file bypassing the
- *		usual file space allocation calls, and thus avoiding the 
- *		potential infinite loops.
- *
- *		The purpose of this function is to allocate file space for 
- *		the header and section info of the target free space manager 
- *		directly from the VFD if needed.  In this case the function 
- *		also re-inserts the header and section info in the metadata 
- *		cache with this allocation.
- *
- *		Note that if f->shared->alignment > 1, and EOA is not a 
- *		multiple of the alignment, it is possible that performing 
- *		this allocation may generate a fragment of file space in 
- *		addition to the space allocated for the section info.
- *
- *		At present we deal with this by screaming and dying.  
- *		Obviously, this is not acceptatable, but it should do 
- *		for now.
- *
- *		
- * Return:	Success:	non-negative
- *		Failure:	negative
- *
- * Programmer:	John Mainzer
- *		6/6/16
- *
- *-------------------------------------------------------------------------
- */
-herr_t
-H5FS_alloc_vfd_alloc_hdr_and_section_info(H5F_t *f, hid_t dxpl_id, 
-    H5FS_t *fspace, haddr_t *fs_addr_ptr)
-{
-    herr_t ret_value = SUCCEED;         /* Return value */
-
-    FUNC_ENTER_NOAPI_TAG(dxpl_id, H5AC__FREESPACE_TAG, FAIL)
-
-    /* Check arguments */
-    HDassert(f);
-    HDassert(fspace);
-    HDassert(fs_addr_ptr);
-
-    /* The section info should be unlocked */
-    HDassert(fspace->sinfo_lock_count == 0);
-
-    /* No space should be allocated */
-    HDassert(*fs_addr_ptr == HADDR_UNDEF);
-    HDassert(fspace->addr == HADDR_UNDEF);
-    HDassert(fspace->sect_addr == HADDR_UNDEF);
-    HDassert(fspace->alloc_sect_size == 0);
-
-    /* Check if any space will be needed */
-    if(fspace->serial_sect_count > 0) {
-        haddr_t sect_addr;      /* Address of sinfo */
-
-        /* The section info is floating, so fspace->sinfo should be defined */
-        HDassert(fspace->sinfo);
-
-        /* Start by allocating file space for the header */
-        if(HADDR_UNDEF == (fspace->addr = H5MF_vfd_alloc(f, dxpl_id, H5FD_MEM_FSPACE_HDR,
-                (hsize_t)H5FS_HEADER_SIZE(f), FALSE)))
-            HGOTO_ERROR(H5E_FSPACE, H5E_CANTALLOC, FAIL, "can't allocate file space for hdr")
-
-        /* Cache the new free space header (pinned) */
-        if(H5AC_insert_entry(f, dxpl_id, H5AC_FSPACE_HDR, fspace->addr, fspace, H5AC__PIN_ENTRY_FLAG) < 0)
-            HGOTO_ERROR(H5E_FSPACE, H5E_CANTINSERT, FAIL, "can't add free space header to cache")
-
-
-        /* Now allocate file space for the section info */
-        if(HADDR_UNDEF == (sect_addr = H5MF_vfd_alloc(f, dxpl_id, H5FD_MEM_FSPACE_SINFO,
-                fspace->sect_size, FALSE)))
-            HGOTO_ERROR(H5E_FSPACE, H5E_CANTALLOC, FAIL, "can't allocate file space")
-
-        /* Update fspace->alloc_sect_size and fspace->sect_addr to reflect 
-         * the allocation 
-         */
-        fspace->alloc_sect_size = fspace->sect_size;
-        fspace->sect_addr = sect_addr;
-
-        /* We have changed the sinfo address -- Mark free space header dirty */
-        if(H5AC_mark_entry_dirty(fspace) < 0)
-            HGOTO_ERROR(H5E_FSPACE, H5E_CANTMARKDIRTY, FAIL, "unable to mark free space header as dirty")
-
-        /* Insert the new section info into the metadata cache.  */
-
-        /* Question: Do we need to worry about this insertion causing an 
-         * eviction from the metadata cache?  Think on this.  If so, add a 
-         * flag to H5AC_insert() to force it to skip the call to make space in
-         * cache.
-         *
-         * On reflection, no.
-         *
-         * On a regular file close, any eviction will not change the 
-         * the contents of the free space manger(s), as all entries 
-         * should have correct file space allocated by the time this 
-         * function is called.
-         *
-         * In the cache image case, the selection of entries for inclusion
-         * in the cache image will not take place until after this call.
-         * (Recall that this call is made during the metadata fsm settle
-         * routine, which is called during the serialization routine in 
-         * the cache image case.  Entries are not selected for inclusion
-         * in the image until after the cache is serialized.)  
-         *
-         *                                        JRM -- 11/4/16
-         */
-        if(H5AC_insert_entry(f, dxpl_id, H5AC_FSPACE_SINFO, sect_addr, fspace->sinfo, H5AC__NO_FLAGS_SET) < 0)
-            HGOTO_ERROR(H5E_FSPACE, H5E_CANTINSERT, FAIL, "can't add free space sinfo to cache")
-
-        /* Since space has been allocated for the section info and the sinfo
-         * has been inserted into the cache, relinquish owership (i.e. float)
-         * the section info.
-         */
-        fspace->sinfo = NULL;
-
-        /* Set the address of the free space header, on success */
-        *fs_addr_ptr = fspace->addr;
-    } /* end if */
-
-done:
-    FUNC_LEAVE_NOAPI_TAG(ret_value, FAIL)
-} /* H5FS_alloc_vfd_alloc_hdr_and_section_info() */
-
-
-/*-------------------------------------------------------------------------
  * Function:    H5FS_free()
  *
  * Purpose:     Free space for free-space manager header and section info header
@@ -1076,7 +910,7 @@ done:
  *-------------------------------------------------------------------------
  */
 herr_t
-H5FS_free(H5F_t *f, H5FS_t *fspace, hid_t dxpl_id)
+H5FS_free(H5F_t *f, H5FS_t *fspace, hid_t dxpl_id, hbool_t free_file_space)
 {
     haddr_t	saved_addr;             /* Previous address of item */
     unsigned    cache_flags;        /* Flags for unprotecting cache entries */
@@ -1123,7 +957,8 @@ H5FS_free(H5F_t *f, H5FS_t *fspace, hid_t dxpl_id)
 
         /* Free space for the free-space manager section info */
         if(!H5F_IS_TMP_ADDR(f, saved_addr)) {
-            if(H5MF_xfree(f, H5FD_MEM_FSPACE_SINFO, dxpl_id, saved_addr, saved_size) < 0)
+            if(free_file_space &&
+               H5MF_xfree(f, H5FD_MEM_FSPACE_SINFO, dxpl_id, saved_addr, saved_size) < 0)
                 HGOTO_ERROR(H5E_FSPACE, H5E_CANTFREE, FAIL, "unable to release free space sections")
         } /* end if */
 
@@ -1165,7 +1000,8 @@ H5FS_free(H5F_t *f, H5FS_t *fspace, hid_t dxpl_id)
         fspace->addr = HADDR_UNDEF;
 
         /* Free space for the free-space manager header */
-        if(H5MF_xfree(f, H5FD_MEM_FSPACE_HDR, dxpl_id, saved_addr, (hsize_t)H5FS_HEADER_SIZE(f)) < 0)
+        if(free_file_space &&
+           H5MF_xfree(f, H5FD_MEM_FSPACE_HDR, dxpl_id, saved_addr, (hsize_t)H5FS_HEADER_SIZE(f)) < 0)
             HGOTO_ERROR(H5E_FSPACE, H5E_CANTFREE, FAIL, "unable to free free space header")
     } /* end if */
 
@@ -1339,6 +1175,23 @@ done:
     FUNC_LEAVE_NOAPI(ret_value)
 } /* end H5FS_sinfo_dest() */
 
+herr_t 
+H5FS_get_sect_count(const H5FS_t *frsp, hsize_t *tot_sect_count)
+{
+    herr_t ret_value = SUCCEED; /* Return value */
+
+    FUNC_ENTER_NOAPI_NOINIT_NOERR
+
+    /* Check arguments. */
+    HDassert(frsp);
+    HDassert(tot_sect_count);
+
+    /* Report statistics for free space */
+    *tot_sect_count = frsp->serial_sect_count;
+
+    FUNC_LEAVE_NOAPI(ret_value)
+}
+
 #ifdef H5FS_DEBUG_ASSERT
 
 /*-------------------------------------------------------------------------
diff --git a/src/H5FScache.c b/src/H5FScache.c
index dcc8122..ddc66fd 100644
--- a/src/H5FScache.c
+++ b/src/H5FScache.c
@@ -37,6 +37,7 @@
 #include "H5private.h"		/* Generic Functions			*/
 #include "H5ACprivate.h"        /* Metadata cache                       */
 #include "H5Eprivate.h"		/* Error handling		  	*/
+#include "H5Fprivate.h"		/* File          			*/
 #include "H5FSpkg.h"		/* File free space			*/
 #include "H5MFprivate.h"	/* File memory management		*/
 #include "H5VMprivate.h"	/* Vectors and arrays 			*/
@@ -296,7 +297,7 @@ H5FS__cache_hdr_deserialize(const void *_image, size_t len, void *_udata,
     /* # of section classes */
     /* (only check if we actually have some classes) */
     UINT16DECODE(image, nclasses);
-    if(fspace->nclasses > 0 && fspace->nclasses != nclasses)
+    if(fspace->nclasses > 0 && nclasses > fspace->nclasses)
         HGOTO_ERROR(H5E_FSPACE, H5E_CANTLOAD, NULL, "section class count mismatch")
 
     /* Shrink percent */
@@ -596,9 +597,11 @@ H5FS__cache_hdr_pre_serialize(H5F_t *f, hid_t dxpl_id, void *_thing,
          * 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_POINT_OF_NO_RETURN(f)) {
+            HDassert(fspace->serial_sect_count > 0);
+            HDassert(fspace->sect_size > 0);
+            HDassert(fspace->alloc_sect_size == (size_t)fspace->sect_size);
+        } /* end if */
 
         if(H5F_IS_TMP_ADDR(f, fspace->sect_addr)) {
             unsigned sect_status = 0;
@@ -702,10 +705,12 @@ H5FS__cache_hdr_serialize(const H5F_t *f, void *_image, size_t len,
      * 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)));
+
+    if(!H5F_POINT_OF_NO_RETURN(f))
+        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)));
 
     /* Magic number */
     HDmemcpy(image, H5FS_HDR_MAGIC, (size_t)H5_SIZEOF_MAGIC);
@@ -1061,7 +1066,7 @@ H5FS__cache_sinfo_deserialize(const void *_image, size_t len, void *_udata,
 
                 /* 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)
+                    if(H5FS_sect_add(udata->f, udata->dxpl_id, udata->fspace, new_sect, H5FS_ADD_DESERIALIZING, udata) < 0)
                         HGOTO_ERROR(H5E_FSPACE, H5E_CANTINSERT, NULL, "can't add section to free space manager")
             } /* end for */
         } while(image < (((const uint8_t *)_image + old_sect_size) - H5FS_SIZEOF_CHKSUM));
@@ -1177,8 +1182,9 @@ H5FS__cache_sinfo_pre_serialize(H5F_t *f, hid_t dxpl_id, void *_thing,
     HDassert(new_len);
     HDassert(flags);
 
-    /* we shouldn't be called if the section info is empty */
-    HDassert(fspace->serial_sect_count > 0);
+    /* we shouldn't be called if the section info is empty, unless we hit the point of no return. */
+    if(!H5F_POINT_OF_NO_RETURN(f))
+        HDassert(fspace->serial_sect_count > 0);
 
     sinfo_addr = addr; /* this will change if we relocate the section data */
 
diff --git a/src/H5FSpkg.h b/src/H5FSpkg.h
index 4411236..ab97955 100644
--- a/src/H5FSpkg.h
+++ b/src/H5FSpkg.h
@@ -187,8 +187,9 @@ struct H5FS_t {
                                 /* 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                            */
+    hsize_t    align_thres;     /* Threshold for alignment              */
+
 
 /* Memory data structures (not stored directly) */
     H5FS_section_class_t *sect_cls; /* Array of section classes for this free list */
diff --git a/src/H5FSprivate.h b/src/H5FSprivate.h
index 1816a6e..74f9dcb 100644
--- a/src/H5FSprivate.h
+++ b/src/H5FSprivate.h
@@ -67,6 +67,12 @@
                                          *      managed sections is in flux)
                                          */
 
+#define H5FS_PAGE_END_NO_ADD    0x08    /* For "small" page fs:
+                                         * Don't add section to free space:
+                                         * 	when the section is at page end and
+                                         * 	when the section size is <= "small"
+                                         */
+
 /* Flags for deserialize callback  */
 #define H5FS_DESERIALIZE_NO_ADD  0x01   /* Don't add section to free space
                                          *      manager after it's deserialized
@@ -98,11 +104,11 @@ typedef struct H5FS_section_class_t {
     herr_t (*term_cls)(struct H5FS_section_class_t *);                  /* Routine to terminate class-specific settings */
 
     /* Object methods */
-    herr_t (*add)(H5FS_section_info_t *, unsigned *, void *);       /* Routine called when section is about to be added to manager */
+    herr_t (*add)(H5FS_section_info_t **, unsigned *, void *);       /* Routine called when section is about to be added to manager */
     herr_t (*serialize)(const struct H5FS_section_class_t *, const H5FS_section_info_t *, uint8_t *);        /* Routine to serialize a "live" section into a buffer */
     H5FS_section_info_t *(*deserialize)(const struct H5FS_section_class_t *, hid_t dxpl_id, const uint8_t *, haddr_t, hsize_t, unsigned *);     /* Routine to deserialize a buffer into a "live" section */
     htri_t (*can_merge)(const H5FS_section_info_t *, const H5FS_section_info_t *, void *);  /* Routine to determine if two nodes are mergable */
-    herr_t (*merge)(H5FS_section_info_t *, H5FS_section_info_t *, void *);      /* Routine to merge two nodes */
+    herr_t (*merge)(H5FS_section_info_t **, H5FS_section_info_t *, void *);      /* Routine to merge two nodes */
     htri_t (*can_shrink)(const H5FS_section_info_t *, void *);        /* Routine to determine if node can shrink container */
     herr_t (*shrink)(H5FS_section_info_t **, void *);   /* Routine to shrink container */
     herr_t (*free)(H5FS_section_info_t *);              /* Routine to free node */
@@ -182,9 +188,8 @@ H5_DLL herr_t H5FS_delete(H5F_t *f, hid_t dxpl_id, haddr_t fs_addr);
 H5_DLL herr_t H5FS_close(H5F_t *f, hid_t dxpl_id, H5FS_t *fspace);
 H5_DLL herr_t H5FS_alloc_hdr(H5F_t *f, H5FS_t *fspace, haddr_t *fs_addr, hid_t dxpl_id);
 H5_DLL herr_t H5FS_alloc_sect(H5F_t *f, H5FS_t *fspace, hid_t dxpl_id);
-H5_DLL herr_t H5FS_alloc_vfd_alloc_hdr_and_section_info(H5F_t *f, hid_t dxpl_id, 
-    H5FS_t *fspace, haddr_t *fs_addr_ptr);
-H5_DLL herr_t H5FS_free(H5F_t *f, H5FS_t *fspace, hid_t dxpl_id);
+H5_DLL herr_t H5FS_free(H5F_t *f, H5FS_t *fspace, hid_t dxpl_id, 
+    hbool_t free_file_space);
 
 /* Free space section routines */
 H5_DLL herr_t H5FS_sect_add(H5F_t *f, hid_t dxpl_id, H5FS_t *fspace,
@@ -192,7 +197,7 @@ H5_DLL herr_t H5FS_sect_add(H5F_t *f, hid_t dxpl_id, H5FS_t *fspace,
 H5_DLL htri_t H5FS_sect_try_merge(H5F_t *f, hid_t dxpl_id, H5FS_t *fspace,
     H5FS_section_info_t *sect, unsigned flags, void *op_data);
 H5_DLL htri_t H5FS_sect_try_extend(H5F_t *f, hid_t dxpl_id, H5FS_t *fspace,
-    haddr_t addr, hsize_t size, hsize_t extra_requested);
+    haddr_t addr, hsize_t size, hsize_t extra_requested, unsigned flags, void *op_data);
 H5_DLL herr_t H5FS_sect_remove(H5F_t *f, hid_t dxpl_id, H5FS_t *fspace,
     H5FS_section_info_t *node);
 H5_DLL htri_t H5FS_sect_find(H5F_t *f, hid_t dxpl_id, H5FS_t *fspace,
@@ -202,11 +207,18 @@ H5_DLL herr_t H5FS_sect_stats(const H5FS_t *fspace, hsize_t *tot_space,
     hsize_t *nsects);
 H5_DLL herr_t H5FS_sect_change_class(H5F_t *f, hid_t dxpl_id, H5FS_t *fspace,
     H5FS_section_info_t *sect, uint16_t new_class);
-H5_DLL htri_t H5FS_sect_try_shrink_eoa(const H5F_t *f, hid_t dxpl_id, const H5FS_t *fspace, void *op_data);
-H5_DLL herr_t H5FS_sect_query_last_sect(const H5FS_t *fspace, haddr_t *sect_addr, hsize_t *sect_size);
+H5_DLL htri_t H5FS_sect_try_shrink_eoa(H5F_t *f, hid_t dxpl_id, H5FS_t *fspace,
+    void *op_data);
 
 /* Statistics routine */
 H5_DLL herr_t H5FS_stat_info(const H5F_t *f, const H5FS_t *frsp, H5FS_stat_t *stats);
+H5_DLL herr_t H5FS_get_sect_count(const H5FS_t *frsp, hsize_t *tot_sect_count);
+
+/* free space manager settling routines */
+H5_DLL herr_t H5FS_vfd_alloc_hdr_and_section_info_if_needed(H5F_t *f,
+                                                          hid_t dxpl_id,
+                                                          H5FS_t *fspace,
+                                                          haddr_t *fs_addr_ptr);
 
 /* Debugging routines for dumping file structures */
 H5_DLL herr_t H5FS_debug(H5F_t *f, hid_t dxpl_id, haddr_t addr,
diff --git a/src/H5FSsection.c b/src/H5FSsection.c
index efe0031..49ff003 100644
--- a/src/H5FSsection.c
+++ b/src/H5FSsection.c
@@ -25,6 +25,8 @@
 /* Module Setup */
 /****************/
 
+#define H5F_FRIEND              /*suppress error about including H5Fpkg   */
+
 #include "H5FSmodule.h"         /* This source code file is part of the H5FS module */
 
 
@@ -33,6 +35,7 @@
 /***********/
 #include "H5private.h"		/* Generic Functions			*/
 #include "H5Eprivate.h"		/* Error handling		  	*/
+#include "H5Fpkg.h"             /* File access                          */
 #include "H5FSpkg.h"		/* File free space			*/
 #include "H5MFprivate.h"	/* File memory management		*/
 #include "H5VMprivate.h"		/* Vectors and arrays 			*/
@@ -1210,11 +1213,13 @@ H5FS_sect_merge(H5FS_t *fspace, H5FS_section_info_t **sect, void *op_data)
                             HGOTO_ERROR(H5E_FSPACE, H5E_CANTRELEASE, FAIL, "can't remove section from internal data structures")
 
                         /* Merge the two sections together */
-                        if((*tmp_sect_cls->merge)(tmp_sect, *sect, op_data) < 0)
+                        if((*tmp_sect_cls->merge)(&tmp_sect, *sect, op_data) < 0)
                             HGOTO_ERROR(H5E_FSPACE, H5E_CANTINSERT, FAIL, "can't merge two sections")
 
                         /* Retarget section pointer to 'less than' node that was merged into */
                         *sect = tmp_sect;
+			if(*sect == NULL) 
+			    HGOTO_DONE(ret_value);
 
                         /* Indicate successful merge occurred */
                         modified = TRUE;
@@ -1254,9 +1259,13 @@ H5FS_sect_merge(H5FS_t *fspace, H5FS_section_info_t **sect, void *op_data)
                             HGOTO_ERROR(H5E_FSPACE, H5E_CANTRELEASE, FAIL, "can't remove section from internal data structures")
 
                         /* Merge the two sections together */
-                        if((*sect_cls->merge)(*sect, tmp_sect, op_data) < 0)
+                        if((*sect_cls->merge)(sect, tmp_sect, op_data) < 0)
                             HGOTO_ERROR(H5E_FSPACE, H5E_CANTINSERT, FAIL, "can't merge two sections")
 
+                        /* It's possible that the merge caused the section to be deleted (particularly in the paged allocation case) */
+                        if(*sect == NULL) 
+                            HGOTO_DONE(ret_value);
+
                         /* Indicate successful merge occurred */
                         modified = TRUE;
                     } /* end if */
@@ -1383,7 +1392,7 @@ HDfprintf(stderr, "%s: *sect = {%a, %Hu, %u, %s}\n", FUNC, sect->addr, sect->siz
     /* Call "add" section class callback, if there is one */
     cls = &fspace->sect_cls[sect->type];
     if(cls->add) {
-        if((*cls->add)(sect, &flags, op_data) < 0)
+        if((*cls->add)(&sect, &flags, op_data) < 0)
             HGOTO_ERROR(H5E_FSPACE, H5E_CANTINSERT, FAIL, "'add' section class callback failed")
     } /* end if */
 
@@ -1411,7 +1420,7 @@ HDfprintf(stderr, "%s: fspace->tot_space = %Hu\n", FUNC, fspace->tot_space);
 #endif /* H5FS_SINFO_DEBUG */
     /* Mark free space sections as changed */
     /* (if adding sections while deserializing sections, don't set the flag) */
-    if(!(flags & H5FS_ADD_DESERIALIZING))
+    if(!(flags & (H5FS_ADD_DESERIALIZING | H5FS_PAGE_END_NO_ADD)))
         sinfo_modified = TRUE;
 
 done:
@@ -1444,7 +1453,7 @@ HDfprintf(stderr, "%s: Leaving, ret_value = %d\n", FUNC, ret_value);
  */
 htri_t
 H5FS_sect_try_extend(H5F_t *f, hid_t dxpl_id, H5FS_t *fspace, haddr_t addr,
-    hsize_t size, hsize_t extra_requested)
+    hsize_t size, hsize_t extra_requested, unsigned flags, void *op_data)
 {
     hbool_t sinfo_valid = FALSE;        /* Whether the section info is valid */
     hbool_t sinfo_modified = FALSE;     /* Whether the section info was modified */
@@ -1528,10 +1537,16 @@ if(_section_)
                     /* Adjust section by amount requested */
                     sect->addr += extra_requested;
                     sect->size -= extra_requested;
-
-                    /* Re-add adjusted section to free sections data structures */
-                    if(H5FS_sect_link(fspace, sect, 0) < 0)
-                        HGOTO_ERROR(H5E_FSPACE, H5E_CANTINSERT, FAIL, "can't insert free space section into skip list")
+                    if(cls->add)
+                        if((*cls->add)(&sect, &flags, op_data) < 0)
+                            HGOTO_ERROR(H5E_FSPACE, H5E_CANTINSERT, FAIL, "'add' section class callback failed")
+
+                    /* Re-adding the section could cause it to disappear (particularly when paging) */
+                    if(sect) {
+                        /* Re-add adjusted section to free sections data structures */
+                        if(H5FS_sect_link(fspace, sect, 0) < 0)
+                            HGOTO_ERROR(H5E_FSPACE, H5E_CANTINSERT, FAIL, "can't insert free space section into skip list")
+                    } /* end if */
                 } /* end if */
                 else {
                     /* Sanity check */
@@ -1667,7 +1682,7 @@ HDfprintf(stderr, "%s: fspace->sinfo->nbins = %u\n", FUNC, fspace->sinfo->nbins)
 HDfprintf(stderr, "%s: bin = %u\n", FUNC, bin);
 #endif /* QAK */
     alignment = fspace->alignment;
-    if(!((alignment > 1) && (request >= fspace->threshold)))
+    if(!((alignment > 1) && (request >= fspace->align_thres)))
         alignment = 0; /* no alignment */
 
     do {
@@ -2349,7 +2364,7 @@ HDfprintf(stderr, "%s: sect->size = %Hu, sect->addr = %a, sect->type = %u\n", "H
  *-------------------------------------------------------------------------
  */
 htri_t
-H5FS_sect_try_shrink_eoa(const H5F_t *f, hid_t dxpl_id, const H5FS_t *fspace, void *op_data)
+H5FS_sect_try_shrink_eoa(H5F_t *f, hid_t dxpl_id, H5FS_t *fspace, void *op_data)
 {
     hbool_t sinfo_valid = FALSE;        /* Whether the section info is valid */
     hbool_t section_removed = FALSE;    /* Whether a section was removed */
@@ -2406,42 +2421,264 @@ done:
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5FS_sect_query_last_sect
- *
- * Purpose:	Retrieve info about the last section on the merge list
- *
- * Return:	Success:	non-negative
- *		Failure:	negative
+ * Function:    H5FS_vfd_alloc_hdr_and_section_info_if_needed
+ *
+ * Purpose:     This function is part of a hack to patch over a design
+ *              flaw in the free space managers for file space allocation.
+ *              Specifically, if a free space manager allocates space for
+ *              its own section info, it is possible for it to
+ *              go into an infinite loop as it:
+ *
+ *                      1) computes the size of the section info
+ *
+ *                      2) allocates file space for the section info
+ *
+ *                      3) notices that the size of the section info
+ *                         has changed
+ *
+ *                      4) deallocates the section info file space and
+ *                         returns to 1) above.
+ *
+ *              Similarly, if it allocates space for its own header, it
+ *              can go into an infinte loop as it:
+ *
+ *                      1) allocates space for the header
+ *
+ *                      2) notices that the free space manager is empty
+ *                         and thus should not have file space allocated
+ *                         to its header
+ *
+ *                      3) frees the space allocated to the header
+ *
+ *                      4) notices that the free space manager is not
+ *                         empty and thus must have file space allocated
+ *                         to it, and thus returns to 1) above.
+ *
+ *              In a nutshell, the solution applied in this hack is to
+ *              deallocate file space for the free space manager(s) that
+ *              handle FSM header and/or section info file space allocations,
+ *              wait until all other allocation/deallocation requests have
+ *              been handled, and then test to see if the free space manager(s)
+ *              in question are empty.  If they are, do nothing.  If they
+ *              are not, allocate space for them at end of file bypassing the
+ *              usual file space allocation calls, and thus avoiding the
+ *              potential infinite loops.
+ *
+ *              The purpose of this function is to allocate file space for
+ *              the header and section info of the target free space manager
+ *              directly from the VFD if needed.  In this case the function
+ *              also re-inserts the header and section info in the metadata
+ *              cache with this allocation.
+ *
+ *		When paged allocation is not enabled, allocation of space 
+ *		for the free space manager header and section info is 
+ *		straight forward -- we simply allocate the space directly 
+ *		from file driver.
+ *
+ *              Note that if f->shared->alignment > 1, and EOA is not a
+ *              multiple of the alignment, it is possible that performing
+ *              these allocations may generate a fragment of file space in
+ *              addition to the space allocated for the section info.  This
+ *		excess space is dropped on the floor.  As shall be seen,
+ *		it will usually be reclaimed later.
+ *
+ *		When page allocation is enabled, things are more difficult,
+ *		as there is the possibility that page buffering will be 
+ *		enabled when the free space managers are read.  To allow
+ *		for this, we must ensure that space allocated for the 
+ *		free space manager header and section info is either larger
+ *		than a page, or resides completely withing a page.
+ *
+ *		Do this by allocating space for the free space header and 
+ *		section info starting at page boundaries, and extending 
+ *		allocation to the next page boundary.  This of course wastes
+ *		space, but see below.
+ *
+ *              On the first free space allocation / deallocation after the 
+ *		next file open, we will read the self referential free space 
+ *		managers, float them and reduce the EOA to its value prior 
+ *		to allocation of file space for the self referential free 
+ *              space managers on the preceeding file close.  This EOA value 
+ *		is stored in the free space manager superblock extension 
+ *		message.
+ *
+ * Return:      Success:        non-negative
+ *              Failure:        negative
  *
- * Programmer:	Vailin Choi
+ * Programmer:  John Mainzer
+ *              6/6/16
  *
  *-------------------------------------------------------------------------
  */
 herr_t
-H5FS_sect_query_last_sect(const H5FS_t *fspace, haddr_t *sect_addr, hsize_t *sect_size)
+H5FS_vfd_alloc_hdr_and_section_info_if_needed(H5F_t *f, hid_t dxpl_id,
+    H5FS_t *fspace, haddr_t *fs_addr_ptr)
 {
-    FUNC_ENTER_NOAPI_NOINIT_NOERR
+    hsize_t	hdr_alloc_size;
+    hsize_t	sinfo_alloc_size;
+    haddr_t     sect_addr = HADDR_UNDEF;        /* address of sinfo */
+    haddr_t     eoa_frag_addr = HADDR_UNDEF;    /* Address of fragment at EOA */
+    hsize_t     eoa_frag_size = 0;      /* Size of fragment at EOA */
+    haddr_t     eoa = HADDR_UNDEF;      /* Initial EOA for the file */
+    herr_t ret_value = SUCCEED;         /* Return value */
+
+    FUNC_ENTER_NOAPI_NOINIT
 
     /* Check arguments. */
+    HDassert(f);
+    HDassert(f->shared);
+    HDassert(f->shared->lf);
     HDassert(fspace);
+    HDassert(fs_addr_ptr);
 
-    if(fspace->sinfo && fspace->sinfo->merge_list) {
-        H5SL_node_t *last_node;             /* Last node in merge list */
+    /* the section info should be unlocked */
+    HDassert(fspace->sinfo_lock_count == 0);
 
-        /* Check for last node in the merge list */
-        if(NULL != (last_node = H5SL_last(fspace->sinfo->merge_list))) {
-            H5FS_section_info_t *tmp_sect;      /* Temporary free space section */
+    /* no space should be allocated */
+    HDassert(*fs_addr_ptr == HADDR_UNDEF);
+    HDassert(fspace->addr == HADDR_UNDEF);
+    HDassert(fspace->sect_addr == HADDR_UNDEF);
+    HDassert(fspace->alloc_sect_size == 0);
 
-            /* Get the pointer to the last section, from the last node */
-            tmp_sect = (H5FS_section_info_t *)H5SL_item(last_node);
-            HDassert(tmp_sect);
-	    if(sect_addr)
-                *sect_addr = tmp_sect->addr;
-	    if(sect_size)
-                *sect_size = tmp_sect->size;
-	} /* end if */
+    /* persistant free space managers must be enabled */
+    HDassert(f->shared->fs_persist);
+
+    /* At present, all free space strategies enable the free space managers.
+     * This will probably change -- at which point this assertion should 
+     * be revisited.
+     */
+    /* Updated: Only the following two strategies enable the free-space managers */
+    HDassert((f->shared->fs_strategy == H5F_FSPACE_STRATEGY_FSM_AGGR) ||
+             (f->shared->fs_strategy == H5F_FSPACE_STRATEGY_PAGE));
+
+    if(fspace->serial_sect_count > 0) {
+        /* the section info is floating, so space->sinfo should be defined */
+        HDassert(fspace->sinfo);
+
+        /* start by allocating file space for the header */
+
+        /* Get the EOA for the file -- need for sanity check below */
+        if(HADDR_UNDEF == (eoa = H5F_get_eoa(f, H5FD_MEM_FSPACE_HDR)))
+           HGOTO_ERROR(H5E_RESOURCE, H5E_CANTGET, FAIL, "Unable to get eoa")
+
+        /* check for overlap into temporary allocation space */
+        if(H5F_IS_TMP_ADDR(f, (eoa + fspace->sect_size)))
+            HGOTO_ERROR(H5E_RESOURCE, H5E_BADRANGE, FAIL, "hdr file space alloc will overlap into 'temporary' file space")
+
+	hdr_alloc_size = H5FS_HEADER_SIZE(f);
+
+	/* if page allocation is enabled, extend the hdr_alloc_size to the 
+	 * next page boundary.
+         */
+        if(H5F_PAGED_AGGR(f)) {
+            HDassert(0 == (eoa % f->shared->fs_page_size));
+
+	    hdr_alloc_size = ((hdr_alloc_size / f->shared->fs_page_size) + 1) * f->shared->fs_page_size;
+
+            HDassert(hdr_alloc_size >= H5FS_HEADER_SIZE(f));
+            HDassert((hdr_alloc_size % f->shared->fs_page_size) == 0);
+        } /* end if */
+
+        /* allocate space for the hdr */
+        if(HADDR_UNDEF == (fspace->addr = H5FD_alloc(f->shared->lf, dxpl_id,
+                                                   H5FD_MEM_FSPACE_HDR, f, 
+                                                   hdr_alloc_size,
+                                                   &eoa_frag_addr,
+                                                   &eoa_frag_size)))
+            HGOTO_ERROR(H5E_FSPACE, H5E_CANTALLOC, FAIL, "can't allocate file space for hdr")
+
+        /* if the file alignement is 1, there should be no
+         * eoa fragment.  Otherwise, drop any fragment on the floor.
+         */
+        HDassert((eoa_frag_size == 0) || (f->shared->alignment != 1));
+
+        /* Cache the new free space header (pinned) */
+        if(H5AC_insert_entry(f, dxpl_id, H5AC_FSPACE_HDR, fspace->addr, fspace, H5AC__PIN_ENTRY_FLAG) < 0)
+            HGOTO_ERROR(H5E_FSPACE, H5E_CANTINIT, FAIL, "can't add free space header to cache")
+
+        *fs_addr_ptr = fspace->addr;
+
+        /* now allocate file space for the section info */
+
+        /* Get the EOA for the file -- need for sanity check below */
+        if(HADDR_UNDEF == (eoa = H5F_get_eoa(f, H5FD_MEM_FSPACE_SINFO)))
+            HGOTO_ERROR(H5E_FSPACE, H5E_CANTGET, FAIL, "Unable to get eoa")
+
+        /* check for overlap into temporary allocation space */
+        if(H5F_IS_TMP_ADDR(f, (eoa + fspace->sect_size)))
+            HGOTO_ERROR(H5E_FSPACE, H5E_BADRANGE, FAIL, "sinfo file space alloc will overlap into 'temporary' file space")
+
+        sinfo_alloc_size = fspace->sect_size;
+
+	/* if paged allocation is enabled, extend the sinfo_alloc_size to the 
+	 * next page boundary.
+         */
+        if(H5F_PAGED_AGGR(f)) {
+            HDassert(0 == (eoa % f->shared->fs_page_size));
+
+	    sinfo_alloc_size = ((sinfo_alloc_size / f->shared->fs_page_size) + 1) * f->shared->fs_page_size;
+
+            HDassert(sinfo_alloc_size >= fspace->sect_size);
+            HDassert((sinfo_alloc_size % f->shared->fs_page_size) == 0);
+        } /* end if */
+
+        /* allocate space for the section info */
+        if(HADDR_UNDEF == (sect_addr = H5FD_alloc(f->shared->lf, dxpl_id,
+                                                  H5FD_MEM_FSPACE_SINFO, f, 
+                                                  sinfo_alloc_size,
+                                                  &eoa_frag_addr,
+                                                  &eoa_frag_size)))
+            HGOTO_ERROR(H5E_FSPACE, H5E_CANTALLOC, FAIL, "can't allocate file space")
+
+        /* if the file alignement is 1, there should be no
+         * eoa fragment.  Otherwise, drop the fragment on the floor.
+         */
+        HDassert((eoa_frag_size == 0) || (f->shared->alignment != 1));
+
+        /* update fspace->alloc_sect_size and fspace->sect_addr to reflect
+         * the allocation
+         */
+        fspace->alloc_sect_size = fspace->sect_size;
+        fspace->sect_addr = sect_addr;
+
+        /* insert the new section info into the metadata cache.  */
+
+        /* Question: Do we need to worry about this insertion causing an
+         * eviction from the metadata cache?  Think on this.  If so, add a
+         * flag to H5AC_insert() to force it to skip the call to make space in
+         * cache.
+         *
+         * On reflection, no.
+         *
+         * On a regular file close, any eviction will not change the
+         * the contents of the free space manger(s), as all entries
+         * should have correct file space allocated by the time this
+         * function is called.
+         *
+         * In the cache image case, the selection of entries for inclusion
+         * in the cache image will not take place until after this call.
+         * (Recall that this call is made during the metadata fsm settle
+         * routine, which is called during the serialization routine in
+         * the cache image case.  Entries are not selected for inclusion
+         * in the image until after the cache is serialized.)
+         *
+         *                                        JRM -- 11/4/16
+         */
+        if(H5AC_insert_entry(f, dxpl_id, H5AC_FSPACE_SINFO, sect_addr, fspace->sinfo, H5AC__NO_FLAGS_SET) < 0)
+            HGOTO_ERROR(H5E_FSPACE, H5E_CANTINIT, FAIL, "can't add free space sinfo to cache")
+
+        /* We have changed the sinfo address -- Mark free space header dirty */
+        if(H5AC_mark_entry_dirty(fspace) < 0)
+            HGOTO_ERROR(H5E_FSPACE, H5E_CANTMARKDIRTY, FAIL, "unable to mark free space header as dirty")
+
+        /* since space has been allocated for the section info and the sinfo
+         * has been inserted into the cache, relinquish owership (i.e. float)
+         * the section info.
+         */
+        fspace->sinfo = NULL;
     } /* end if */
 
-    FUNC_LEAVE_NOAPI(SUCCEED)
-} /* H5FS_sect_query_last_sect() */
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* H5FS_vfd_alloc_hdr_and_section_info_if_needed() */
 
diff --git a/src/H5Fint.c b/src/H5Fint.c
index 3c98c8f..794be50 100644
--- a/src/H5Fint.c
+++ b/src/H5Fint.c
@@ -182,6 +182,14 @@ H5F_get_access_plist(H5F_t *f, hbool_t app_ref)
         efc_size = H5F_efc_max_nfiles(f->shared->efc);
     if(H5P_set(new_plist, H5F_ACS_EFC_SIZE_NAME, &efc_size) < 0)
         HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't set elink file cache size")
+    if(f->shared->page_buf != NULL) {
+        if(H5P_set(new_plist, H5F_ACS_PAGE_BUFFER_SIZE_NAME, &(f->shared->page_buf->max_size)) < 0)
+            HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't set page buffer size")
+        if(H5P_set(new_plist, H5F_ACS_PAGE_BUFFER_MIN_META_PERC_NAME, &(f->shared->page_buf->min_meta_perc)) < 0)
+            HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't set minimum metadata fraction of page buffer")
+        if(H5P_set(new_plist, H5F_ACS_PAGE_BUFFER_MIN_RAW_PERC_NAME, &(f->shared->page_buf->min_raw_perc)) < 0)
+            HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't set minimum raw data fraction of page buffer")
+    } /* end if */
 #ifdef H5_HAVE_PARALLEL
     if(H5P_set(new_plist, H5_COLL_MD_READ_FLAG_NAME, &(f->coll_md_read)) < 0)
         HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't set collective metadata read flag")
@@ -597,11 +605,26 @@ H5F_new(H5F_file_t *shared, unsigned flags, hid_t fcpl_id, hid_t fapl_id, H5FD_t
         f->shared->flags = flags;
         f->shared->sohm_addr = HADDR_UNDEF;
         f->shared->sohm_vers = HDF5_SHAREDHEADER_VERSION;
-        for(u = 0; u < NELMTS(f->shared->fs_addr); u++)
-            f->shared->fs_addr[u] = HADDR_UNDEF;
         f->shared->accum.loc = HADDR_UNDEF;
         f->shared->lf = lf;
 
+        /* Initialization for handling file space */
+        for(u = 0; u < NELMTS(f->shared->fs_addr); u++) {
+            f->shared->fs_state[u] = H5F_FS_STATE_CLOSED;
+            f->shared->fs_addr[u] = HADDR_UNDEF;
+            f->shared->fs_man[u] = NULL;
+        } /* end for */
+        f->shared->first_alloc_dealloc = FALSE;
+        f->shared->eoa_pre_fsm_fsalloc = HADDR_UNDEF;
+        f->shared->eoa_post_fsm_fsalloc = HADDR_UNDEF;
+        f->shared->eoa_post_mdci_fsalloc = HADDR_UNDEF;
+
+        /* Initialization for handling file space (for paged aggregation) */
+        f->shared->pgend_meta_thres = H5F_FILE_SPACE_PGEND_META_THRES;
+
+        /* intialize point of no return */
+        f->shared->point_of_no_return = FALSE;
+
         /*
          * Copy the file creation and file access property lists into the
          * new file handle.  We do this early because some values might need
@@ -621,8 +644,19 @@ H5F_new(H5F_file_t *shared, unsigned flags, hid_t fcpl_id, hid_t fapl_id, H5FD_t
         HDassert(f->shared->sohm_nindexes < 255);
         if(H5P_get(plist, H5F_CRT_FILE_SPACE_STRATEGY_NAME, &f->shared->fs_strategy) < 0)
             HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, NULL, "can't get file space strategy")
+        if(H5P_get(plist, H5F_CRT_FREE_SPACE_PERSIST_NAME, &f->shared->fs_persist) < 0)
+            HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, NULL, "can't get file space persisting status")
         if(H5P_get(plist, H5F_CRT_FREE_SPACE_THRESHOLD_NAME, &f->shared->fs_threshold) < 0)
             HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, NULL, "can't get free-space section threshold")
+        if(H5P_get(plist, H5F_CRT_FILE_SPACE_PAGE_SIZE_NAME, &f->shared->fs_page_size) < 0)
+            HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, NULL, "can't get file space page size")
+        HDassert(f->shared->fs_page_size >= H5F_FILE_SPACE_PAGE_SIZE_MIN);
+
+        /* Temporary for multi/split drivers: fail file creation 
+             when persisting free-space or using paged aggregation strategy */
+        if(H5F_HAS_FEATURE(f, H5FD_FEAT_PAGED_AGGR))
+            if(f->shared->fs_strategy == H5F_FSPACE_STRATEGY_PAGE || f->shared->fs_persist)
+                HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, NULL, "can't open with this strategy or persistent fs")
 
         /* Get the FAPL values to cache */
         if(NULL == (plist = (H5P_genplist_t *)H5I_object(fapl_id)))
@@ -972,6 +1006,11 @@ H5F__dest(H5F_t *f, hid_t meta_dxpl_id, hid_t raw_dxpl_id, hbool_t flush)
             /* Push error, but keep going*/
             HDONE_ERROR(H5E_FILE, H5E_CANTRELEASE, FAIL, "problems closing file")
 
+        /* Shutdown the page buffer cache */
+        if(H5PB_dest(f) < 0)
+            /* Push error, but keep going*/
+            HDONE_ERROR(H5E_FILE, H5E_CANTRELEASE, FAIL, "problems closing page buffer cache")
+
         /* Clean up the metadata cache log location string */
         if(f->shared->mdc_log_location)
             f->shared->mdc_log_location = (char *)H5MM_xfree(f->shared->mdc_log_location);
@@ -1142,6 +1181,9 @@ H5F_open(const char *name, unsigned flags, hid_t fcpl_id, hid_t fapl_id,
     H5P_genplist_t     *a_plist;            /*file access property list     */
     H5F_close_degree_t  fc_degree;          /*file close degree             */
     hid_t               raw_dxpl_id = H5AC_rawdata_dxpl_id;    /* Raw data dxpl used by library        */
+    size_t              page_buf_size;
+    unsigned            page_buf_min_meta_perc;
+    unsigned            page_buf_min_raw_perc;
     hbool_t             set_flag = FALSE;   /*set the status_flags in the superblock */
     hbool_t             clear = FALSE;      /*clear the status_flags 	    */
     hbool_t             evict_on_close;     /* evict on close value from plist  */
@@ -1292,6 +1334,25 @@ H5F_open(const char *name, unsigned flags, hid_t fcpl_id, hid_t fapl_id,
     if(NULL == (a_plist = (H5P_genplist_t *)H5I_object(fapl_id)))
         HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, NULL, "not file access property list")
 
+    /* Check if page buffering is enabled */
+    if(H5P_get(a_plist, H5F_ACS_PAGE_BUFFER_SIZE_NAME, &page_buf_size) < 0)
+        HGOTO_ERROR(H5E_FILE, H5E_CANTGET, NULL, "can't get page buffer size")
+    if(page_buf_size) {
+#ifdef H5_HAVE_PARALLEL
+        /* Collective metadata writes are not supported with page buffering */
+        if(file->coll_md_write)
+            HGOTO_ERROR(H5E_FILE, H5E_CANTOPENFILE, NULL, "collective metadata writes are not supported with page buffering")
+
+        /* Temporary: fail file create when page buffering feature is enabled for parallel */
+        HGOTO_ERROR(H5E_FILE, H5E_CANTOPENFILE, NULL, "page buffering is disabled for parallel")
+#endif /* H5_HAVE_PARALLEL */
+        /* Query for other page buffer cache properties */
+        if(H5P_get(a_plist, H5F_ACS_PAGE_BUFFER_MIN_META_PERC_NAME, &page_buf_min_meta_perc) < 0)
+            HGOTO_ERROR(H5E_FILE, H5E_CANTGET, NULL, "can't get minimum metadata fraction of page buffer")
+        if(H5P_get(a_plist, H5F_ACS_PAGE_BUFFER_MIN_RAW_PERC_NAME, &page_buf_min_raw_perc) < 0)
+            HGOTO_ERROR(H5E_FILE, H5E_CANTGET, NULL, "can't get minimum raw data fraction of page buffer")
+    } /* end if */
+
     /*
      * Read or write the file superblock, depending on whether the file is
      * empty or not.
@@ -1302,6 +1363,11 @@ H5F_open(const char *name, unsigned flags, hid_t fcpl_id, hid_t fapl_id,
          * to create & write the superblock.
          */
 
+        /* Create the page buffer before initializing the superblock */
+        if(page_buf_size)
+            if(H5PB_create(file, page_buf_size, page_buf_min_meta_perc, page_buf_min_raw_perc) < 0)
+                HGOTO_ERROR(H5E_FILE, H5E_CANTINIT, NULL, "unable to create page buffer")
+
         /* Initialize information about the superblock and allocate space for it */
         /* (Writes superblock extension messages, if there are any) */
         if(H5F__super_init(file, meta_dxpl_id) < 0)
@@ -1319,6 +1385,11 @@ H5F_open(const char *name, unsigned flags, hid_t fcpl_id, hid_t fapl_id,
         if(H5F__super_read(file, meta_dxpl_id, raw_dxpl_id, TRUE) < 0)
             HGOTO_ERROR(H5E_FILE, H5E_READERROR, NULL, "unable to read superblock")
 
+        /* Create the page buffer before initializing the superblock */
+        if(page_buf_size)
+            if(H5PB_create(file, page_buf_size, page_buf_min_meta_perc, page_buf_min_raw_perc) < 0)
+                HGOTO_ERROR(H5E_FILE, H5E_CANTINIT, NULL, "unable to create page buffer")
+
         /* Open the root group */
         if(H5G_mkroot(file, meta_dxpl_id, FALSE) < 0)
             HGOTO_ERROR(H5E_FILE, H5E_CANTOPENFILE, NULL, "unable to read root group")
@@ -1527,6 +1598,11 @@ H5F__flush_phase2(H5F_t *f, hid_t meta_dxpl_id, hid_t raw_dxpl_id, hbool_t closi
         /* Push error, but keep going*/
         HDONE_ERROR(H5E_IO, H5E_CANTFLUSH, FAIL, "unable to flush metadata accumulator")
 
+    /* Flush the page buffer */
+    if(H5PB_flush(&fio_info) < 0)
+        /* Push error, but keep going*/
+        HDONE_ERROR(H5E_IO, H5E_CANTFLUSH, FAIL, "page buffer flush failed")
+
     /* Flush file buffers to disk. */
     if(H5FD_flush(f->shared->lf, meta_dxpl_id, closing) < 0)
         /* Push error, but keep going*/
@@ -2652,6 +2728,38 @@ done:
     FUNC_LEAVE_NOAPI(ret_value)
 } /* end H5F__set_eoa() */
 
+
+/*-------------------------------------------------------------------------
+ * Function:	H5F__set_paged_aggr
+ *
+ * Purpose:	Quick and dirty routine to set the file's paged_aggr mode
+ *
+ * Return:	Non-negative on success/Negative on failure
+ *
+ * Programmer:	Quincey Koziol <koziol@hdfgroup.org>
+ *		June 19, 2015
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5F__set_paged_aggr(const H5F_t *f, hbool_t paged)
+{
+    herr_t ret_value = SUCCEED;         /* Return value */
+
+    FUNC_ENTER_PACKAGE
+
+    /* Sanity check */
+    HDassert(f);
+    HDassert(f->shared);
+
+    /* Dispatch to driver */
+    if(H5FD_set_paged_aggr(f->shared->lf, paged) < 0)
+        HGOTO_ERROR(H5E_FILE, H5E_CANTSET, FAIL, "driver set paged aggr mode failed")
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5F__set_paged_aggr() */
+
 #ifdef H5_HAVE_PARALLEL
 
 /*-------------------------------------------------------------------------
diff --git a/src/H5Fio.c b/src/H5Fio.c
index d40483f..6d23995 100644
--- a/src/H5Fio.c
+++ b/src/H5Fio.c
@@ -39,6 +39,7 @@
 #include "H5Fpkg.h"             /* File access				*/
 #include "H5FDprivate.h"	/* File drivers				*/
 #include "H5Iprivate.h"		/* IDs			  		*/
+#include "H5PBprivate.h"	/* Page Buffer				*/
 
 
 /****************/
@@ -129,9 +130,9 @@ H5F_block_read(const H5F_t *f, H5FD_mem_t type, haddr_t addr, size_t size,
             HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "can't get property list")
     } /* end else */
 
-    /* Pass through metadata accumulator layer */
-    if(H5F__accum_read(&fio_info, map_type, addr, size, buf) < 0)
-        HGOTO_ERROR(H5E_IO, H5E_READERROR, FAIL, "read through metadata accumulator failed")
+    /* Pass through page buffer layer */
+    if(H5PB_read(&fio_info, map_type, addr, size, buf) < 0)
+        HGOTO_ERROR(H5E_IO, H5E_READERROR, FAIL, "read through page buffer failed")
 
 done:
     FUNC_LEAVE_NOAPI(ret_value)
@@ -191,9 +192,9 @@ H5F_block_write(const H5F_t *f, H5FD_mem_t type, haddr_t addr, size_t size,
             HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "can't get property list")
     } /* end else */
 
-    /* Pass through metadata accumulator layer */
-    if(H5F__accum_write(&fio_info, map_type, addr, size, buf) < 0)
-        HGOTO_ERROR(H5E_IO, H5E_WRITEERROR, FAIL, "write through metadata accumulator failed")
+    /* Pass through page buffer layer */
+    if(H5PB_write(&fio_info, map_type, addr, size, buf) < 0)
+        HGOTO_ERROR(H5E_IO, H5E_WRITEERROR, FAIL, "write through page buffer failed")
 
 done:
     FUNC_LEAVE_NOAPI(ret_value)
diff --git a/src/H5Fpkg.h b/src/H5Fpkg.h
index aaa19d9..4dd9e20 100644
--- a/src/H5Fpkg.h
+++ b/src/H5Fpkg.h
@@ -42,6 +42,7 @@
 #include "H5FSprivate.h"	/* File free space                      */
 #include "H5Gprivate.h"		/* Groups 			  	*/
 #include "H5Oprivate.h"         /* Object header messages               */
+#include "H5PBprivate.h"        /* Page buffer                          */
 #include "H5UCprivate.h"	/* Reference counted object functions	*/
 
 
@@ -68,8 +69,8 @@
 
 /* Macro to abstract checking whether file is using a free space manager */
 #define H5F_HAVE_FREE_SPACE_MANAGER(F)  \
-    ((F)->shared->fs_strategy == H5F_FILE_SPACE_ALL ||                        \
-            (F)->shared->fs_strategy == H5F_FILE_SPACE_ALL_PERSIST)
+    ((F)->shared->fs_strategy == H5F_FSPACE_STRATEGY_FSM_AGGR ||                        \
+     (F)->shared->fs_strategy == H5F_FSPACE_STRATEGY_PAGE)
 
 /* Macros for encoding/decoding superblock */
 #define H5F_MAX_DRVINFOBLOCK_SIZE  1024         /* Maximum size of superblock driver info buffer */
@@ -200,13 +201,6 @@ typedef struct H5F_meta_accum_t {
     hbool_t             dirty;          /* Flag to indicate that the accumulated metadata is dirty */
 } H5F_meta_accum_t;
 
-/* Enum for free space manager state */
-typedef enum H5F_fs_state_t {
-    H5F_FS_STATE_CLOSED,                /* Free space manager is closed */
-    H5F_FS_STATE_OPEN,                  /* Free space manager has been opened */
-    H5F_FS_STATE_DELETING               /* Free space manager is being deleted */
-} H5F_fs_state_t;
-
 /* A record of the mount table */
 typedef struct H5F_mount_t {
     struct H5G_t	*group;	/* Mount point group held open		*/
@@ -281,6 +275,7 @@ struct H5F_file_t {
     unsigned long feature_flags; /* VFL Driver feature Flags            */
     haddr_t	maxaddr;	/* Maximum address for file             */
 
+    H5PB_t      *page_buf;                  /* The page buffer cache                */
     H5AC_t      *cache;		/* The object cache	 		*/
     H5AC_cache_config_t
 		mdc_initCacheCfg; /* initial configuration for the      */
@@ -316,19 +311,38 @@ struct H5F_file_t {
     H5UC_t *grp_btree_shared;   /* Ref-counted group B-tree node info   */
 
     /* File space allocation information */
-    H5F_file_space_type_t fs_strategy;	/* File space handling strategy		*/
+    H5F_fspace_strategy_t fs_strategy;      /* File space handling strategy	*/
     hsize_t     fs_threshold;	/* Free space section threshold 	*/
+    hbool_t fs_persist;                     /* Free-space persist or not */
     hbool_t     use_tmp_space;  /* Whether temp. file space allocation is allowed */
     haddr_t	tmp_addr;       /* Next address to use for temp. space in the file */
+    hbool_t point_of_no_return;             /* flag to indicate that we can't go back and delete a freespace header when it's used up */
+
+    H5F_fs_state_t fs_state[H5F_MEM_PAGE_NTYPES];   /* State of free space manager for each type */
+    haddr_t fs_addr[H5F_MEM_PAGE_NTYPES];           /* Address of free space manager info for each type */
+    H5FS_t *fs_man[H5F_MEM_PAGE_NTYPES];            /* Free space manager for each file space type */
+    hbool_t first_alloc_dealloc;            /* TRUE iff free space managers   */
+                                            /* are persistant and have not    */
+                                            /* been used accessed for either  */
+                                            /* allocation or deallocation     */
+                                            /* since file open.               */
+    haddr_t eoa_pre_fsm_fsalloc;	    /* eoa pre file space allocation  */
+                                            /* for self referential FSMs      */
+    haddr_t eoa_post_fsm_fsalloc;           /* eoa post file space allocation */
+                                            /* for self referential FSMs      */
+    haddr_t eoa_post_mdci_fsalloc;          /* eoa past file space allocation */
+                                            /* for metadata cache image, or   */
+                                            /* HADDR_UNDEF if no cache image. */
+
+    /* Free-space aggregation info */
     unsigned fs_aggr_merge[H5FD_MEM_NTYPES];    /* Flags for whether free space can merge with aggregator(s) */
-    H5F_fs_state_t fs_state[H5FD_MEM_NTYPES];   /* State of free space manager for each type */
-    haddr_t fs_addr[H5FD_MEM_NTYPES];   /* Address of free space manager info for each type */
-    H5FS_t *fs_man[H5FD_MEM_NTYPES];    /* Free space manager for each file space type */
-    H5FD_mem_t fs_type_map[H5FD_MEM_NTYPES]; /* Mapping of "real" file space type into tracked type */
-    H5F_blk_aggr_t meta_aggr;   /* Metadata aggregation info */
-                                /* (if aggregating metadata allocations) */
-    H5F_blk_aggr_t sdata_aggr;  /* "Small data" aggregation info */
-                                /* (if aggregating "small data" allocations) */
+    H5FD_mem_t fs_type_map[H5FD_MEM_NTYPES];    /* Mapping of "real" file space type into tracked type */
+    H5F_blk_aggr_t meta_aggr;   	        /* Metadata aggregation info (if aggregating metadata allocations) */
+    H5F_blk_aggr_t sdata_aggr;                  /* "Small data" aggregation info (if aggregating "small data" allocations) */
+
+    /* Paged aggregation info */
+    hsize_t fs_page_size;                           /* File space page size */
+    size_t pgend_meta_thres;                        /* Do not track page end meta section <= this threshold */
 
     /* Metadata accumulator information */
     H5F_meta_accum_t accum;     /* Metadata accumulator info           	*/
@@ -383,7 +397,7 @@ H5FL_EXTERN(H5F_file_t);
 /* General routines */
 H5F_t *H5F_new(H5F_file_t *shared, unsigned flags, hid_t fcpl_id,
     hid_t fapl_id, H5FD_t *lf);
-herr_t H5F__dest(H5F_t *f, hid_t meta_dxpl_id, hid_t raw_dxpl_id, hbool_t flush);
+H5_DLL herr_t H5F__dest(H5F_t *f, hid_t meta_dxpl_id, hid_t raw_dxpl_id, hbool_t flush);
 H5_DLL herr_t H5F__flush(H5F_t *f, hid_t meta_dxpl_id, hid_t raw_dxpl_id, hbool_t closing);
 H5_DLL htri_t H5F__is_hdf5(const char *name, hid_t meta_dxpl_id, hid_t raw_dxpl_id);
 H5_DLL herr_t H5F_get_objects(const H5F_t *f, unsigned types, size_t max_index, hid_t *obj_id_list, hbool_t app_ref, size_t *obj_id_count_ptr);
@@ -433,9 +447,16 @@ H5_DLL herr_t H5F_efc_release(H5F_efc_t *efc);
 H5_DLL herr_t H5F_efc_destroy(H5F_efc_t *efc);
 H5_DLL herr_t H5F_efc_try_close(H5F_t *f);
 
+/* Space allocation routines */
+H5_DLL haddr_t H5F_alloc(H5F_t *f, hid_t dxpl_id, H5F_mem_t type, hsize_t size, haddr_t *frag_addr, hsize_t *frag_size);
+H5_DLL herr_t H5F_free(H5F_t *f, hid_t dxpl_id, H5F_mem_t type, haddr_t addr, hsize_t size);
+H5_DLL htri_t H5F_try_extend(H5F_t *f, hid_t dxpl_id, H5FD_mem_t type, 
+    haddr_t blk_end, hsize_t extra_requested);
+
 /* Functions that get/retrieve values from VFD layer */
 H5_DLL herr_t H5F__set_eoa(const H5F_t *f, H5F_mem_t type, haddr_t addr);
 H5_DLL herr_t H5F__set_base_addr(const H5F_t *f, haddr_t addr);
+H5_DLL herr_t H5F__set_paged_aggr(const H5F_t *f, hbool_t paged);
 
 /* Functions that flush or evict */
 H5_DLL herr_t H5F__evict_cache_entries(H5F_t *f, hid_t dxpl_id);
diff --git a/src/H5Fprivate.h b/src/H5Fprivate.h
index f980347..886063a 100644
--- a/src/H5Fprivate.h
+++ b/src/H5Fprivate.h
@@ -315,8 +315,8 @@
 #define H5F_SET_STORE_MSG_CRT_IDX(F, FL)    ((F)->shared->store_msg_crt_idx = (FL))
 #define H5F_GRP_BTREE_SHARED(F) ((F)->shared->grp_btree_shared)
 #define H5F_SET_GRP_BTREE_SHARED(F, RC) (((F)->shared->grp_btree_shared = (RC)) ? SUCCEED : FAIL)
-#define H5F_USE_TMP_SPACE(F)    ((F)->shared->use_tmp_space)
-#define H5F_IS_TMP_ADDR(F, ADDR) (H5F_addr_le((F)->shared->tmp_addr, (ADDR)))
+#define H5F_USE_TMP_SPACE(F)    ((F)->shared->fs.use_tmp_space)
+#define H5F_IS_TMP_ADDR(F, ADDR) (H5F_addr_le((F)->shared->fs.tmp_addr, (ADDR)))
 #define H5F_SET_LATEST_FLAGS(F, FL)  ((F)->shared->latest_flags = (FL))
 #ifdef H5_HAVE_PARALLEL
 #define H5F_COLL_MD_READ(F)     ((F)->coll_md_read)
@@ -324,6 +324,12 @@
 #define H5F_USE_MDC_LOGGING(F)  ((F)->shared->use_mdc_logging)
 #define H5F_START_MDC_LOG_ON_ACCESS(F)  ((F)->shared->start_mdc_log_on_access)
 #define H5F_MDC_LOG_LOCATION(F) ((F)->shared->mdc_log_location)
+#define H5F_ALIGNMENT(F)   	((F)->shared->alignment)
+#define H5F_THRESHOLD(F)   	((F)->shared->threshold)
+#define H5F_PGEND_META_THRES(F) ((F)->shared->fs.pgend_meta_thres)
+#define H5F_POINT_OF_NO_RETURN(F) ((F)->shared->fs.point_of_no_return)
+#define H5F_FIRST_ALLOC_DEALLOC(F) ((F)->shared->first_alloc_dealloc)
+#define H5F_EOA_PRE_FSM_FSALLOC(F) ((F)->shared->eoa_pre_fsm_fsalloc)
 #else /* H5F_MODULE */
 #define H5F_INTENT(F)           (H5F_get_intent(F))
 #define H5F_OPEN_NAME(F)        (H5F_get_open_name(F))
@@ -375,6 +381,12 @@
 #define H5F_USE_MDC_LOGGING(F)  (H5F_use_mdc_logging(F))
 #define H5F_START_MDC_LOG_ON_ACCESS(F)  (H5F_start_mdc_log_on_access(F))
 #define H5F_MDC_LOG_LOCATION(F) (H5F_mdc_log_location(F))
+#define H5F_ALIGNMENT(F)    	(H5F_get_alignment(F))
+#define H5F_THRESHOLD(F)    	(H5F_get_threshold(F))
+#define H5F_PGEND_META_THRES(F) (H5F_get_pgend_meta_thres(F))
+#define H5F_POINT_OF_NO_RETURN(F) (H5F_get_point_of_no_return(F))
+#define H5F_FIRST_ALLOC_DEALLOC(F) (H5F_get_first_alloc_dealloc(F))
+#define H5F_EOA_PRE_FSM_FSALLOC(F) (H5F_get_eoa_pre_fsm_fsalloc(F))
 #endif /* H5F_MODULE */
 
 
@@ -448,7 +460,9 @@
 #define H5F_CRT_SHMSG_LIST_MAX_NAME  "shmsg_list_max"   /* Shared message list maximum size */
 #define H5F_CRT_SHMSG_BTREE_MIN_NAME "shmsg_btree_min"  /* Shared message B-tree minimum size */
 #define H5F_CRT_FILE_SPACE_STRATEGY_NAME "file_space_strategy"  /* File space handling strategy */
+#define H5F_CRT_FREE_SPACE_PERSIST_NAME "free_space_persist"  	/* Free-space persisting status */
 #define H5F_CRT_FREE_SPACE_THRESHOLD_NAME "free_space_threshold"  /* Free space section threshold */
+#define H5F_CRT_FILE_SPACE_PAGE_SIZE_NAME "file_space_page_size"  /* File space page size */
 
 
 
@@ -484,6 +498,9 @@
 #define H5F_ACS_CORE_WRITE_TRACKING_PAGE_SIZE_NAME "core_write_tracking_page_size" /* The page size in kiB when core VFD write tracking is enabled */
 #define H5F_ACS_COLL_MD_WRITE_FLAG_NAME         "collective_metadata_write" /* property indicating whether metadata writes are done collectively or not */
 #define H5F_ACS_META_CACHE_INIT_IMAGE_CONFIG_NAME "mdc_initCacheImageCfg" /* Initial metadata cache image creation configuration */
+#define H5F_ACS_PAGE_BUFFER_SIZE_NAME           "page_buffer_size" /* the maximum size for the page buffer cache */
+#define H5F_ACS_PAGE_BUFFER_MIN_META_PERC_NAME  "page_buffer_min_meta_perc" /* the min metadata percentage for the page buffer cache */
+#define H5F_ACS_PAGE_BUFFER_MIN_RAW_PERC_NAME   "page_buffer_min_raw_perc" /* the min raw data percentage for the page buffer cache */
 
 /* ======================== File Mount properties ====================*/
 #define H5F_MNT_SYM_LOCAL_NAME 		"local"                 /* Whether absolute symlinks local to file. */
@@ -522,10 +539,34 @@
 						/* See format specification on version 1 B-trees */
 
 /* Default file space handling strategy */
-#define H5F_FILE_SPACE_STRATEGY_DEF	        H5F_FILE_SPACE_ALL
+#define H5F_FILE_SPACE_STRATEGY_DEF	        H5F_FSPACE_STRATEGY_FSM_AGGR
+
+/* Default free space section threshold used by free-space managers */
+#define H5F_FREE_SPACE_PERSIST_DEF	        FALSE
+
 /* Default free space section threshold used by free-space managers */
 #define H5F_FREE_SPACE_THRESHOLD_DEF	        1
 
+/* For paged aggregation: default file space page size when not set */
+#define H5F_FILE_SPACE_PAGE_SIZE_DEF     	4096    
+/* For paged aggregation: minimum value for file space page size */
+#define H5F_FILE_SPACE_PAGE_SIZE_MIN     	512
+
+/* For paged aggregation: drop free-space with size <= this threshold for small meta section */
+#define H5F_FILE_SPACE_PGEND_META_THRES  10    
+
+/* Default for threshold for alignment (can be set via H5Pset_alignment()) */
+#define H5F_ALIGN_DEF			1
+/* Default for alignment (can be set via H5Pset_alignment()) */
+#define H5F_ALIGN_THRHD_DEF		1
+/* Default size for meta data aggregation block (can be set via H5Pset_meta_block_size()) */
+#define H5F_META_BLOCK_SIZE_DEF		2048
+/* Default size for small data aggregation block (can be set via H5Pset_small_data_block_size()) */
+#define H5F_SDATA_BLOCK_SIZE_DEF	2048
+
+/* Check for file using paged aggregation */
+#define H5F_PAGED_AGGR(F) (F->shared->fs_strategy == H5F_FSPACE_STRATEGY_PAGE && F->shared->fs_page_size)
+
 /* Metadata read attempt values */
 #define H5F_METADATA_READ_ATTEMPTS		1	/* Default # of read attempts for non-SWMR access */
 #define H5F_SWMR_METADATA_READ_ATTEMPTS		100	/* Default # of read attempts for SWMR access */
@@ -648,6 +689,34 @@ typedef struct H5F_block_t {
     hsize_t length;             /* Length of the block in the file */
 } H5F_block_t;
 
+/* Enum for free space manager state */
+typedef enum H5F_fs_state_t {
+    H5F_FS_STATE_CLOSED = 0,                /* Free space manager is closed */
+    H5F_FS_STATE_OPEN = 1,                  /* Free space manager has been opened */
+    H5F_FS_STATE_DELETING = 2               /* Free space manager is being deleted */
+} H5F_fs_state_t;
+
+/* For paged aggregation */
+/* The values 0 to 6 is the same as H5F_mem_t */
+typedef enum H5F_mem_page_t {
+    H5F_MEM_PAGE_DEFAULT = 0,       /* Not used */
+    H5F_MEM_PAGE_SUPER = 1,
+    H5F_MEM_PAGE_BTREE = 2,          
+    H5F_MEM_PAGE_DRAW = 3, 
+    H5F_MEM_PAGE_GHEAP = 4,      
+    H5F_MEM_PAGE_LHEAP = 5,      
+    H5F_MEM_PAGE_OHDR = 6,      
+    H5F_MEM_PAGE_LARGE_SUPER = 7,
+    H5F_MEM_PAGE_LARGE_BTREE = 8,
+    H5F_MEM_PAGE_LARGE_DRAW = 9,
+    H5F_MEM_PAGE_LARGE_GHEAP = 10,
+    H5F_MEM_PAGE_LARGE_LHEAP = 11,
+    H5F_MEM_PAGE_LARGE_OHDR = 12,
+    H5F_MEM_PAGE_NTYPES = 13       /* Sentinel value - must be last */
+} H5F_mem_page_t;
+
+#define H5F_MEM_PAGE_META       H5F_MEM_PAGE_SUPER          /* Small-sized meta data */
+#define H5F_MEM_PAGE_GENERIC    H5F_MEM_PAGE_LARGE_SUPER    /* Large-sized generic: meta and raw */
 
 /*****************************/
 /* Library-private Variables */
@@ -682,6 +751,10 @@ H5_DLL hid_t H5F_get_access_plist(H5F_t *f, hbool_t app_ref);
 H5_DLL hid_t H5F_get_id(H5F_t *file, hbool_t app_ref);
 H5_DLL herr_t H5F_get_obj_count(const H5F_t *f, unsigned types, hbool_t app_ref, size_t *obj_id_count_ptr);
 H5_DLL herr_t H5F_get_obj_ids(const H5F_t *f, unsigned types, size_t max_objs, hid_t *oid_list, hbool_t app_ref, size_t *obj_id_count_ptr);
+H5_DLL hsize_t H5F_get_pgend_meta_thres(const H5F_t *f);
+H5_DLL hbool_t H5F_get_point_of_no_return(const H5F_t *f);
+H5_DLL hbool_t H5F_get_first_alloc_dealloc(const H5F_t *f);
+H5_DLL hbool_t H5F_get_eoa_pre_fsm_fsalloc(const H5F_t *f);
 
 /* Functions than retrieve values set/cached from the superblock/FCPL */
 H5_DLL haddr_t H5F_get_base_addr(const H5F_t *f);
@@ -712,6 +785,8 @@ H5_DLL herr_t H5F_set_grp_btree_shared(H5F_t *f, struct H5UC_t *rc);
 H5_DLL hbool_t H5F_use_tmp_space(const H5F_t *f);
 H5_DLL hbool_t H5F_is_tmp_addr(const H5F_t *f, haddr_t addr);
 H5_DLL herr_t H5F_set_latest_flags(H5F_t *f, unsigned flags);
+H5_DLL hsize_t H5F_get_alignment(const H5F_t *f);
+H5_DLL hsize_t H5F_get_threshold(const H5F_t *f);
 #ifdef H5_HAVE_PARALLEL
 H5_DLL H5P_coll_md_read_flag_t H5F_coll_md_read(const H5F_t *f);
 H5_DLL void H5F_set_coll_md_read(H5F_t *f, H5P_coll_md_read_flag_t flag);
diff --git a/src/H5Fpublic.h b/src/H5Fpublic.h
index c57a821..f87aaad 100644
--- a/src/H5Fpublic.h
+++ b/src/H5Fpublic.h
@@ -182,6 +182,17 @@ typedef enum H5F_libver_t {
 } H5F_libver_t;
 
 /* File space handling strategy */
+typedef enum H5F_fspace_strategy_t {
+    H5F_FSPACE_STRATEGY_FSM_AGGR = 0,   /* Mechanisms: free-space managers, aggregators, and virtual file drivers */
+                                        /* This is the library default when not set */
+    H5F_FSPACE_STRATEGY_PAGE = 1,   /* Mechanisms: free-space managers with embedded paged aggregation and virtual file drivers */
+    H5F_FSPACE_STRATEGY_AGGR = 2,   /* Mechanisms: aggregators and virtual file drivers */
+    H5F_FSPACE_STRATEGY_NONE = 3,   /* Mechanisms: virtual file drivers */
+    H5F_FSPACE_STRATEGY_NTYPES      /* must be last */
+} H5F_fspace_strategy_t;
+
+/* Deprecated: File space handling strategy for release 1.10.0 */
+/* They are mapped to H5F_fspace_strategy_t as defined above from release 1.10.1 onwards */
 typedef enum H5F_file_space_type_t {
     H5F_FILE_SPACE_DEFAULT = 0,     /* Default (or current) free space strategy setting */
     H5F_FILE_SPACE_ALL_PERSIST = 1, /* Persistent free space managers, aggregators, virtual file driver */
@@ -253,6 +264,10 @@ H5_DLL herr_t H5Fget_mdc_logging_status(hid_t file_id,
                                         /*OUT*/ hbool_t *is_enabled,
                                         /*OUT*/ hbool_t *is_currently_logging);
 H5_DLL herr_t H5Fformat_convert(hid_t fid);
+H5_DLL herr_t H5Freset_page_buffering_stats(hid_t file_id);
+H5_DLL herr_t H5Fget_page_buffering_stats(hid_t file_id, unsigned accesses[2],
+    unsigned hits[2], unsigned misses[2], unsigned evictions[2], unsigned bypasses[2]);
+
 #ifdef H5_HAVE_PARALLEL
 H5_DLL herr_t H5Fset_mpi_atomicity(hid_t file_id, hbool_t flag);
 H5_DLL herr_t H5Fget_mpi_atomicity(hid_t file_id, hbool_t *flag);
diff --git a/src/H5Fquery.c b/src/H5Fquery.c
index 14dd655..34fe8f9 100644
--- a/src/H5Fquery.c
+++ b/src/H5Fquery.c
@@ -1235,3 +1235,150 @@ H5F_mdc_log_location(const H5F_t *f)
     FUNC_LEAVE_NOAPI(f->shared->mdc_log_location)
 } /* end H5F_mdc_log_location() */
 
+
+/*-------------------------------------------------------------------------
+ * Function:	H5F_get_alignment
+ *
+ * Purpose:	Retrieve the 'alignment' for the file.
+ *
+ * Return:	Success:	Non-negative, the 'alignment'
+ *
+ * 		Failure:	(can't happen)
+ *
+ * Programmer:	Vailin Choi; Dec 2012
+ *
+ *-------------------------------------------------------------------------
+ */
+hsize_t
+H5F_get_alignment(const H5F_t *f)
+{
+    /* Use FUNC_ENTER_NOAPI_NOINIT_NOERR here to avoid performance issues */
+    FUNC_ENTER_NOAPI_NOINIT_NOERR
+
+    HDassert(f);
+    HDassert(f->shared);
+
+    FUNC_LEAVE_NOAPI(f->shared->alignment)
+} /* end H5F_get_alignment() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:	H5F_get_threshold
+ *
+ * Purpose:	Retrieve the 'threshold' for alignment in the file.
+ *
+ * Return:	Success:	Non-negative, the 'threshold'
+ *
+ * 		Failure:	(can't happen)
+ *
+ * Programmer:	Vailin Choi; Dec 2012
+ *
+ *-------------------------------------------------------------------------
+ */
+hsize_t
+H5F_get_threshold(const H5F_t *f)
+{
+    /* Use FUNC_ENTER_NOAPI_NOINIT_NOERR here to avoid performance issues */
+    FUNC_ENTER_NOAPI_NOINIT_NOERR
+
+    HDassert(f);
+    HDassert(f->shared);
+
+    FUNC_LEAVE_NOAPI(f->shared->threshold)
+} /* end H5F_get_threshold() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:	H5F_get_pgend_meta_thres
+ *
+ * Purpose:	Retrieve the 'page end meta threshold size' for the file.
+ *
+ * Return:	Success:	Non-negative, the 'pgend_meta_thres'
+ *
+ * 		Failure:	(can't happen)
+ *
+ * Programmer:	Vailin Choi; Dec 2012
+ *
+ *-------------------------------------------------------------------------
+ */
+hsize_t
+H5F_get_pgend_meta_thres(const H5F_t *f)
+{
+    /* Use FUNC_ENTER_NOAPI_NOINIT_NOERR here to avoid performance issues */
+    FUNC_ENTER_NOAPI_NOINIT_NOERR
+
+    HDassert(f);
+    HDassert(f->shared);
+
+    FUNC_LEAVE_NOAPI(f->shared->pgend_meta_thres)
+} /* end H5F_get_pgend_meta_thres() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:	H5F_get_point_of_no_return
+ *
+ * Purpose:	Retrieve the 'point of no return' value for the file.
+ *
+ * Return:	Success:	Non-negative, the 'point_of_no_return'
+ * 		Failure:	(can't happen)
+ *
+ *-------------------------------------------------------------------------
+ */
+hbool_t
+H5F_get_point_of_no_return(const H5F_t *f)
+{
+    /* Use FUNC_ENTER_NOAPI_NOINIT_NOERR here to avoid performance issues */
+    FUNC_ENTER_NOAPI_NOINIT_NOERR
+
+    HDassert(f);
+    HDassert(f->shared);
+
+    FUNC_LEAVE_NOAPI(f->shared->point_of_no_return)
+} /* end H5F_get_point_of_no_return() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:	H5F_get_first_alloc_dealloc
+ *
+ * Purpose:	Retrieve the 'first alloc / dealloc' value for the file.
+ *
+ * Return:	Success:	Non-negative, the 'first_alloc_dealloc'
+ * 		Failure:	(can't happen)
+ *
+ *-------------------------------------------------------------------------
+ */
+hbool_t
+H5F_get_first_alloc_dealloc(const H5F_t *f)
+{
+    /* Use FUNC_ENTER_NOAPI_NOINIT_NOERR here to avoid performance issues */
+    FUNC_ENTER_NOAPI_NOINIT_NOERR
+
+    HDassert(f);
+    HDassert(f->shared);
+
+    FUNC_LEAVE_NOAPI(f->shared->first_alloc_dealloc)
+} /* end H5F_get_first_alloc_dealloc() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:	H5F_get_eoa_pre_fsm_fsalloc
+ *
+ * Purpose:	Retrieve the 'EOA pre-FSM fsalloc' value for the file.
+ *
+ * Return:	Success:	Non-negative, the 'EOA pre-FSM fsalloc'
+ * 		Failure:	(can't happen)
+ *
+ *-------------------------------------------------------------------------
+ */
+hbool_t
+H5F_get_eoa_pre_fsm_fsalloc(const H5F_t *f)
+{
+    /* Use FUNC_ENTER_NOAPI_NOINIT_NOERR here to avoid performance issues */
+    FUNC_ENTER_NOAPI_NOINIT_NOERR
+
+    HDassert(f);
+    HDassert(f->shared);
+
+    FUNC_LEAVE_NOAPI(f->shared->eoa_pre_fsm_fsalloc)
+} /* end H5F_get_eoa_pre_fsm_fsalloc() */
+
diff --git a/src/H5Fspace.c b/src/H5Fspace.c
new file mode 100644
index 0000000..53570f6
--- /dev/null
+++ b/src/H5Fspace.c
@@ -0,0 +1,226 @@
+/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
+ * Copyright by The HDF Group.                                               *
+ * Copyright by the Board of Trustees of the University of Illinois.         *
+ * All rights reserved.                                                      *
+ *                                                                           *
+ * This file is part of HDF5.  The full HDF5 copyright notice, including     *
+ * terms governing use, modification, and redistribution, is contained in    *
+ * the files COPYING and Copyright.html.  COPYING can be found at the root   *
+ * of the source code distribution tree; Copyright.html can be found at the  *
+ * root level of an installed copy of the electronic HDF5 document set and   *
+ * is linked from the top-level documents page.  It can also be found at     *
+ * http://hdfgroup.org/HDF5/doc/Copyright.html.  If you do not have          *
+ * access to either file, you may request a copy from help@hdfgroup.org.     *
+ * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
+
+/*-------------------------------------------------------------------------
+ *
+ * Created:		H5Fspace.c
+ *			Dec 30 2013
+ *			Quincey Koziol <koziol@hdfgroup.org>
+ *
+ * Purpose:		Space allocation routines for the file.
+ *
+ *-------------------------------------------------------------------------
+ */
+
+/****************/
+/* Module Setup */
+/****************/
+
+#include "H5Fmodule.h"          /* This source code file is part of the H5F module */
+
+
+/***********/
+/* Headers */
+/***********/
+#include "H5private.h"		/* Generic Functions			*/
+#include "H5Eprivate.h"		/* Error handling		  	*/
+#include "H5Fpkg.h"         	/* File access				*/
+#include "H5FDprivate.h"	/* File drivers				*/
+
+
+/****************/
+/* Local Macros */
+/****************/
+
+
+/******************/
+/* Local Typedefs */
+/******************/
+
+
+/********************/
+/* Package Typedefs */
+/********************/
+
+
+/********************/
+/* Local Prototypes */
+/********************/
+
+
+/*********************/
+/* Package Variables */
+/*********************/
+
+
+/*****************************/
+/* Library Private Variables */
+/*****************************/
+
+
+/*******************/
+/* Local Variables */
+/*******************/
+
+
+
+/*-------------------------------------------------------------------------
+ * Function:    H5F_alloc
+ *
+ * Purpose:     Wrapper for H5FD_alloc, to make certain EOA changes are
+ *		reflected in superblock.
+ *
+ * Note:	When the metadata cache routines are updated to allow
+ *		marking an entry dirty without a H5F_t*, this routine should
+ *		be changed to take a H5F_super_t* directly.
+ *
+ * Return:      Success:    The format address of the new file memory.
+ *              Failure:    The undefined address HADDR_UNDEF
+ *
+ * Programmer:  Quincey Koziol
+ *              Monday, December 30, 2013
+ *
+ *-------------------------------------------------------------------------
+ */
+haddr_t
+H5F_alloc(H5F_t *f, hid_t dxpl_id, H5F_mem_t type, hsize_t size, haddr_t *frag_addr, hsize_t *frag_size)
+{
+    haddr_t     ret_value = 0;          /* Return value */
+
+    FUNC_ENTER_NOAPI(HADDR_UNDEF)
+
+    /* check args */
+    HDassert(f);
+    HDassert(f->shared);
+    HDassert(f->shared->lf);
+    HDassert(type >= H5FD_MEM_DEFAULT && type < H5FD_MEM_NTYPES);
+    HDassert(size > 0);
+
+    /* Check whether the file can use temporary addresses */
+    if(f->shared->use_tmp_space) {
+        haddr_t	eoa;            /* Current EOA for the file */
+
+        /* Get the EOA for the file */
+        if(HADDR_UNDEF == (eoa = H5F_get_eoa(f, type)))
+            HGOTO_ERROR(H5E_FILE, H5E_CANTGET, HADDR_UNDEF, "Unable to get eoa")
+
+        /* Check for overlapping into file's temporary allocation space */
+        if(H5F_addr_gt((eoa + size), f->shared->tmp_addr))
+            HGOTO_ERROR(H5E_FILE, H5E_BADRANGE, HADDR_UNDEF, "'normal' file space allocation request will overlap into 'temporary' file space")
+    } /* end if */
+
+    /* Call the file driver 'alloc' routine */
+    ret_value = H5FD_alloc(f->shared->lf, dxpl_id, type, f, size, frag_addr, frag_size);
+    if(!H5F_addr_defined(ret_value))
+        HGOTO_ERROR(H5E_FILE, H5E_CANTALLOC, HADDR_UNDEF, "file driver 'alloc' request failed")
+
+    /* Mark EOA dirty */
+    if(H5F_eoa_dirty(f, dxpl_id) < 0)
+        HGOTO_ERROR(H5E_FILE, H5E_CANTMARKDIRTY, HADDR_UNDEF, "unable to mark EOA as dirty")
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5F_alloc() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:    H5F_free
+ *
+ * Purpose:     Wrapper for H5FD_free, to make certain EOA changes are
+ *		reflected in superblock.
+ *
+ * Note:	When the metadata cache routines are updated to allow
+ *		marking an entry dirty without a H5F_t*, this routine should
+ *		be changed to take a H5F_super_t* directly.
+ *
+ * Return:      Success:        Non-negative
+ *              Failure:        Negative
+ *
+ * Programmer:  Quincey Koziol
+ *              Monday, December 30, 2013
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5F_free(H5F_t *f, hid_t dxpl_id, H5FD_mem_t type, haddr_t addr, hsize_t size)
+{
+    herr_t      ret_value = SUCCEED;       /* Return value */
+
+    FUNC_ENTER_NOAPI(FAIL)
+
+    /* Check args */
+    HDassert(f);
+    HDassert(f->shared);
+    HDassert(f->shared->lf);
+    HDassert(type >= H5FD_MEM_DEFAULT && type < H5FD_MEM_NTYPES);
+    HDassert(size > 0);
+
+    /* Call the file driver 'free' routine */
+    if(H5FD_free(f->shared->lf, dxpl_id, type, f, addr, size) < 0)
+        HGOTO_ERROR(H5E_FILE, H5E_CANTFREE, FAIL, "file driver 'free' request failed")
+
+    /* Mark EOA dirty */
+    if(H5F_eoa_dirty(f, dxpl_id) < 0)
+        HGOTO_ERROR(H5E_FILE, H5E_CANTMARKDIRTY, FAIL, "unable to mark EOA as dirty")
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5F_free() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:    H5F_try_extend
+ *
+ * Purpose:	Extend a block at the end of the file, if possible.
+ *
+ * Note:	When the metadata cache routines are updated to allow
+ *		marking an entry dirty without a H5F_t*, this routine should
+ *		be changed to take a H5F_super_t* directly.
+ *
+ * Return:	Success:	TRUE(1)  - Block was extended
+ *                              FALSE(0) - Block could not be extended
+ * 		Failure:	FAIL
+ *
+ * Programmer:  Quincey Koziol
+ *              Monday, 30 December, 2013
+ *
+ *-------------------------------------------------------------------------
+ */
+htri_t
+H5F_try_extend(H5F_t *f, hid_t dxpl_id, H5FD_mem_t type, haddr_t blk_end, hsize_t extra_requested)
+{
+    htri_t ret_value = FALSE;   /* Return value */
+
+    FUNC_ENTER_NOAPI(FAIL)
+
+    /* check args */
+    HDassert(f);
+    HDassert(f->shared);
+    HDassert(f->shared->lf);
+    HDassert(type >= H5FD_MEM_DEFAULT && type < H5FD_MEM_NTYPES);
+    HDassert(extra_requested > 0);
+
+    /* Extend the object by extending the underlying file */
+    if((ret_value = H5FD_try_extend(f->shared->lf, type, f, dxpl_id, blk_end, extra_requested)) < 0)
+        HGOTO_ERROR(H5E_FILE, H5E_CANTEXTEND, FAIL, "driver try extend request failed")
+
+    /* H5FD_try_extend() updates driver message and marks the superblock
+     * dirty, so no need to do it again here.
+     */
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5F_try_extend() */
+
diff --git a/src/H5Fsuper.c b/src/H5Fsuper.c
index 3050a28..58ef9bb 100644
--- a/src/H5Fsuper.c
+++ b/src/H5Fsuper.c
@@ -29,6 +29,7 @@
 #include "H5Fpkg.h"             /* File access                          */
 #include "H5FDprivate.h"	/* File drivers                         */
 #include "H5Iprivate.h"		/* IDs                                  */
+#include "H5MFprivate.h"        /* File memory management               */
 #include "H5MMprivate.h"	/* Memory management			*/
 #include "H5Pprivate.h"		/* Property lists                       */
 #include "H5SMprivate.h"        /* Shared Object Header Messages        */
@@ -671,32 +672,98 @@ H5F__super_read(H5F_t *f, hid_t meta_dxpl_id, hid_t raw_dxpl_id, hbool_t initial
         if((status = H5O_msg_exists(&ext_loc, H5O_FSINFO_ID, meta_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 */
+            H5O_fsinfo_t fsinfo;   /* File space info message from superblock extension */
+            uint8_t flags;          /* Message flags */
 
-            /* Retrieve the 'free-space manager info' structure */
-	    if(NULL == H5O_msg_read(&ext_loc, H5O_FSINFO_ID, &fsinfo, meta_dxpl_id))
-                HGOTO_ERROR(H5E_FILE, H5E_CANTGET, FAIL, "unable to get free-space manager info message")
+            /* Get message flags */
+            if(H5O_msg_get_flags(&ext_loc, H5O_FSINFO_ID, meta_dxpl_id, &flags) < 0)
+                HGOTO_ERROR(H5E_FILE, H5E_CANTGET, FAIL, "unable to message flags for free-space manager info message")
 
-            /* Check for non-default info */
-	    if(f->shared->fs_strategy != fsinfo.strategy) {
-		f->shared->fs_strategy = fsinfo.strategy;
+            /* If message is NOT marked "unknown"--set up file space info  */
+            if(!(flags & H5O_MSG_FLAG_WAS_UNKNOWN)) {
 
-		/* 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;
+                /* Retrieve the 'file space info' structure */
+                if(NULL == H5O_msg_read(&ext_loc, H5O_FSINFO_ID, &fsinfo, meta_dxpl_id))
+                    HGOTO_ERROR(H5E_FILE, H5E_CANTGET, FAIL, "unable to get free-space manager info message")
 
-		/* 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 */
+                /* Update changed values */
+                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_persist != fsinfo.persist) {
+                    f->shared->fs_persist = fsinfo.persist;
+
+                    /* Set non-default strategy in the property list */
+                    if(H5P_set(c_plist, H5F_CRT_FREE_SPACE_PERSIST_NAME, &fsinfo.persist) < 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 */
+
+                HDassert(f->shared->fs_page_size >= H5F_FILE_SPACE_PAGE_SIZE_MIN);
+                HDassert(fsinfo.page_size >= H5F_FILE_SPACE_PAGE_SIZE_MIN);
+                if(f->shared->fs_page_size != fsinfo.page_size) {
+                    f->shared->fs_page_size = fsinfo.page_size;
+
+                    /* Set file space page size in the property list */
+                    if(H5P_set(c_plist, H5F_CRT_FILE_SPACE_PAGE_SIZE_NAME, &fsinfo.page_size) < 0)
+                        HGOTO_ERROR(H5E_FILE, H5E_CANTSET, FAIL, "unable to set file space page size")
+                } /* end if */
+                if(f->shared->pgend_meta_thres != fsinfo.pgend_meta_thres)
+                    /* Initialize page end meta threshold */
+                    f->shared->pgend_meta_thres = fsinfo.pgend_meta_thres;
+
+                if(f->shared->eoa_pre_fsm_fsalloc != fsinfo.eoa_pre_fsm_fsalloc)
+                    f->shared->eoa_pre_fsm_fsalloc = fsinfo.eoa_pre_fsm_fsalloc;
+
+                /* f->shared->eoa_pre_fsm_fsalloc must always be HADDR_UNDEF
+                 * in the absence of persistant free space managers.
+                 */
+                HDassert((!f->shared->fs_persist) || (f->shared->eoa_pre_fsm_fsalloc != HADDR_UNDEF));
+                HDassert(!f->shared->first_alloc_dealloc);
+
+                if((f->shared->eoa_pre_fsm_fsalloc != HADDR_UNDEF) &&
+                   (H5F_INTENT(f) & H5F_ACC_RDWR))
+                    f->shared->first_alloc_dealloc = TRUE;
+
+                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];
+
+                if(fsinfo.mapped && (rw_flags & H5AC__READ_ONLY_FLAG) == 0) {
 
-	    /* 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];
+                    /* Do the same kluge until we know for sure.  VC */
+#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_remove_msg(f, meta_dxpl_id, H5O_FSINFO_ID) < 0)
+                        HGOTO_ERROR(H5E_FILE, H5E_CANTDELETE, FAIL,  "error in removing message from superblock extension")
+
+                    if(H5F_super_ext_write_msg(f, meta_dxpl_id, H5O_FSINFO_ID, &fsinfo, TRUE, H5O_MSG_FLAG_MARK_IF_UNKNOWN) < 0)
+                        HGOTO_ERROR(H5E_FILE, H5E_WRITEERROR, FAIL, "error in writing fsinfo 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 not marked "unknown" */
         } /* end if */
 
 	/* Check for the extension having a 'metadata cache image' message */
@@ -796,6 +863,10 @@ H5F__super_read(H5F_t *f, hid_t meta_dxpl_id, hid_t raw_dxpl_id, hbool_t initial
     /* Set the pointer to the pinned superblock */
     f->shared->sblock = sblock;
 
+    /* Set the page aggregation mode */
+    if(H5F__set_paged_aggr(f, (hbool_t)H5F_PAGED_AGGR(f)) < 0)
+        HGOTO_ERROR(H5E_FILE, H5E_CANTSET, FAIL, "failed to set paged_aggr status for file driver")
+
 done:
     /* Reset the ring in the DXPL */
     if(H5AC_reset_ring(dxpl, orig_ring) < 0)
@@ -897,7 +968,9 @@ H5F__super_init(H5F_t *f, hid_t dxpl_id)
 
     /* Check for non-default free-space settings */
     if(!(f->shared->fs_strategy == H5F_FILE_SPACE_STRATEGY_DEF &&
-            f->shared->fs_threshold == H5F_FREE_SPACE_THRESHOLD_DEF))
+            f->shared->fs_persist == H5F_FREE_SPACE_PERSIST_DEF &&
+            f->shared->fs_threshold == H5F_FREE_SPACE_THRESHOLD_DEF &&
+	    f->shared->fs_page_size == H5F_FILE_SPACE_PAGE_SIZE_DEF))
         non_default_fs_settings = TRUE;
 
     /* Bump superblock version if latest superblock version support is enabled */
@@ -906,8 +979,12 @@ H5F__super_init(H5F_t *f, hid_t dxpl_id)
     /* Bump superblock version to create superblock extension for SOHM info */
     else if(f->shared->sohm_nindexes > 0)
         super_vers = HDF5_SUPERBLOCK_VERSION_2;
-    /* Bump superblock version to create superblock extension for
-     * non-default file space strategy or non-default free-space threshold
+    /* 
+     *	Bump superblock version to create superblock extension for:
+     * 	-- non-default file space strategy or 
+     * 	-- non-default persisting free-space or 
+     *  -- non-default free-space threshold or
+     *  -- non-default page_size
      */
     else if(non_default_fs_settings)
         super_vers = HDF5_SUPERBLOCK_VERSION_2;
@@ -928,6 +1005,9 @@ H5F__super_init(H5F_t *f, hid_t dxpl_id)
             HGOTO_ERROR(H5E_PLIST, H5E_CANTSET, FAIL, "unable to set superblock version")
     } /* end if */
 
+    if(H5FD_set_paged_aggr(f->shared->lf, (hbool_t)H5F_PAGED_AGGR(f)) < 0)
+        HGOTO_ERROR(H5E_FILE, H5E_CANTINIT, FAIL, "failed to set paged_aggr status for file driver")
+
     /*
      * The superblock starts immediately after the user-defined
      * header, which we have already insured is a proper size. The
@@ -939,9 +1019,12 @@ H5F__super_init(H5F_t *f, hid_t dxpl_id)
 
     /* Sanity check the userblock size vs. the file's allocation alignment */
     if(userblock_size > 0) {
-        if(userblock_size < f->shared->alignment)
+	/* Set up the alignment to use for page or aggr fs */
+	hsize_t alignment = H5F_PAGED_AGGR(f) ? f->shared->fs_page_size : f->shared->alignment;
+
+        if(userblock_size < alignment)
             HGOTO_ERROR(H5E_FILE, H5E_BADVALUE, FAIL, "userblock size must be > file object alignment")
-        if(0 != (userblock_size % f->shared->alignment))
+        if(0 != (userblock_size % alignment))
             HGOTO_ERROR(H5E_FILE, H5E_BADVALUE, FAIL, "userblock size must be an integral multiple of file object alignment")
     } /* end if */
 
@@ -997,10 +1080,6 @@ H5F__super_init(H5F_t *f, hid_t dxpl_id)
     if(super_vers < HDF5_SUPERBLOCK_VERSION_2)
         superblock_size += driver_size;
 
-    /* Reserve space in the file for the superblock, instead of allocating it */
-    if(H5F__set_eoa(f, H5FD_MEM_SUPER, superblock_size) < 0)
-        HGOTO_ERROR(H5E_FILE, H5E_CANTINIT, FAIL, "unable to set EOA value for superblock")
-
     /* Set the ring type in the DXPL */
     if(H5AC_set_ring(dxpl_id, H5AC_RING_SB, &dxpl, &orig_ring) < 0)
         HGOTO_ERROR(H5E_FILE, H5E_CANTSET, FAIL, "unable to set ring value")
@@ -1013,6 +1092,10 @@ H5F__super_init(H5F_t *f, hid_t dxpl_id)
     /* Keep a copy of the superblock info */
     f->shared->sblock = sblock;
 
+    /* Allocate space for the superblock */
+    if(HADDR_UNDEF == H5MF_alloc(f, H5FD_MEM_SUPER, dxpl_id, superblock_size))
+	HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, FAIL, "file allocation failed for superblock")
+
     /* set the drvinfo filed to NULL -- will overwrite this later if needed */
     f->shared->drvinfo = NULL;
 
@@ -1115,17 +1198,23 @@ H5F__super_init(H5F_t *f, hid_t dxpl_id)
         } /* end if */
 
         /* Check for non-default free-space info settings */
-	if(non_default_fs_settings) {
-	    H5FD_mem_t   type;         	/* Memory type for iteration */
-            H5O_fsinfo_t fsinfo;	/* Free space manager info message */
-
-	    /* Write free-space manager info message to superblock extension object header if needed */
-	    fsinfo.strategy = f->shared->fs_strategy;
-	    fsinfo.threshold = f->shared->fs_threshold;
-	    for(type = H5FD_MEM_SUPER; type < H5FD_MEM_NTYPES; H5_INC_ENUM(H5FD_mem_t, type))
-                fsinfo.fs_addr[type-1] = HADDR_UNDEF;
-
-	    if(H5O_msg_create(&ext_loc, H5O_FSINFO_ID, H5O_MSG_FLAG_DONTSHARE, H5O_UPDATE_TIME, &fsinfo, dxpl_id) < 0)
+        if(non_default_fs_settings) {
+            H5F_mem_page_t ptype;
+            H5O_fsinfo_t fsinfo;    /* Free space manager info message */
+
+            /* Write free-space manager info message to superblock extension object header if needed */
+            fsinfo.strategy = f->shared->fs_strategy;
+            fsinfo.persist = f->shared->fs_persist;
+            fsinfo.threshold = f->shared->fs_threshold;
+            fsinfo.page_size = f->shared->fs_page_size;
+            fsinfo.pgend_meta_thres = f->shared->pgend_meta_thres;
+            fsinfo.eoa_pre_fsm_fsalloc = HADDR_UNDEF;
+            fsinfo.mapped = FALSE;
+
+            for(ptype = H5F_MEM_PAGE_SUPER; ptype < H5F_MEM_PAGE_NTYPES; H5_INC_ENUM(H5F_mem_page_t, ptype))
+                fsinfo.fs_addr[ptype - 1] = HADDR_UNDEF;
+
+            if(H5O_msg_create(&ext_loc, H5O_FSINFO_ID, H5O_MSG_FLAG_DONTSHARE | H5O_MSG_FLAG_MARK_IF_UNKNOWN, H5O_UPDATE_TIME, &fsinfo, dxpl_id) < 0)
                 HGOTO_ERROR(H5E_FILE, H5E_CANTINIT, FAIL, "unable to update free-space info header message")
 	} /* end if */
     } /* end if */
diff --git a/src/H5HFsection.c b/src/H5HFsection.c
index 37ff8f4..b113ca1 100644
--- a/src/H5HFsection.c
+++ b/src/H5HFsection.c
@@ -85,14 +85,14 @@ static herr_t H5HF_sect_single_full_dblock(H5HF_hdr_t *hdr, hid_t dxpl_id,
     H5HF_free_section_t *sect);
 
 /* 'single' section callbacks */
-static herr_t H5HF_sect_single_add(H5FS_section_info_t *sect, unsigned *flags,
+static herr_t H5HF_sect_single_add(H5FS_section_info_t **sect, unsigned *flags,
     void *udata);
 static H5FS_section_info_t *H5HF_sect_single_deserialize(const H5FS_section_class_t *cls,
     hid_t dxpl_id, const uint8_t *buf, haddr_t sect_addr, hsize_t sect_size,
     unsigned *des_flags);
 static htri_t H5HF_sect_single_can_merge(const H5FS_section_info_t *sect1,
     const H5FS_section_info_t *sect2, void *udata);
-static herr_t H5HF_sect_single_merge(H5FS_section_info_t *sect1,
+static herr_t H5HF_sect_single_merge(H5FS_section_info_t **sect1,
     H5FS_section_info_t *sect2, void *udata);
 static htri_t H5HF_sect_single_can_shrink(const H5FS_section_info_t *sect,
     void *udata);
@@ -121,7 +121,7 @@ static H5FS_section_info_t *H5HF_sect_row_deserialize(const H5FS_section_class_t
     unsigned *des_flags);
 static htri_t H5HF_sect_row_can_merge(const H5FS_section_info_t *sect1,
     const H5FS_section_info_t *sect2, void *udata);
-static herr_t H5HF_sect_row_merge(H5FS_section_info_t *sect1,
+static herr_t H5HF_sect_row_merge(H5FS_section_info_t **sect1,
     H5FS_section_info_t *sect2, void *udata);
 static htri_t H5HF_sect_row_can_shrink(const H5FS_section_info_t *sect,
     void *udata);
@@ -811,7 +811,7 @@ done:
  *-------------------------------------------------------------------------
  */
 static herr_t
-H5HF_sect_single_add(H5FS_section_info_t *_sect, unsigned *flags, void *_udata)
+H5HF_sect_single_add(H5FS_section_info_t **_sect, unsigned *flags, void *_udata)
 {
     herr_t ret_value = SUCCEED;         /* Return value */
 
@@ -821,7 +821,7 @@ H5HF_sect_single_add(H5FS_section_info_t *_sect, unsigned *flags, void *_udata)
      *  have already been checked when it was first added
      */
     if(!(*flags & H5FS_ADD_DESERIALIZING)) {
-        H5HF_free_section_t *sect = (H5HF_free_section_t *)_sect;   /* Fractal heap free section */
+        H5HF_free_section_t **sect = (H5HF_free_section_t **)_sect;   /* Fractal heap free section */
         H5HF_sect_add_ud_t *udata = (H5HF_sect_add_ud_t *)_udata;   /* User callback data */
         H5HF_hdr_t *hdr = udata->hdr;       /* Fractal heap header */
         hid_t dxpl_id = udata->dxpl_id;     /* DXPL ID for operation */
@@ -832,14 +832,14 @@ H5HF_sect_single_add(H5FS_section_info_t *_sect, unsigned *flags, void *_udata)
 
         /* Check if single section covers entire direct block it's in */
         /* (converts to row section possibly) */
-        if(H5HF_sect_single_full_dblock(hdr, dxpl_id, sect) < 0)
+        if(H5HF_sect_single_full_dblock(hdr, dxpl_id, (*sect)) < 0)
             HGOTO_ERROR(H5E_HEAP, H5E_CANTCONVERT, FAIL, "can't check/convert single section")
 
         /* Set the "returned space" flag if the single section was changed
          *      into a row section, so the "merging & shrinking" algorithm
          *      gets executed in the free space manager
          */
-        if(sect->sect_info.type != H5HF_FSPACE_SECT_SINGLE)
+        if((*sect)->sect_info.type != H5HF_FSPACE_SECT_SINGLE)
             *flags |= H5FS_ADD_RETURNED_SPACE;
     } /* end if */
 
@@ -949,10 +949,10 @@ done:
  *-------------------------------------------------------------------------
  */
 static herr_t
-H5HF_sect_single_merge(H5FS_section_info_t *_sect1, H5FS_section_info_t *_sect2,
+H5HF_sect_single_merge(H5FS_section_info_t **_sect1, H5FS_section_info_t *_sect2,
     void *_udata)
 {
-    H5HF_free_section_t *sect1 = (H5HF_free_section_t *)_sect1;   /* Fractal heap free section */
+    H5HF_free_section_t **sect1 = (H5HF_free_section_t **)_sect1;   /* Fractal heap free section */
     H5HF_free_section_t *sect2 = (H5HF_free_section_t *)_sect2;   /* Fractal heap free section */
     H5HF_sect_add_ud_t *udata = (H5HF_sect_add_ud_t *)_udata;   /* User callback data */
     H5HF_hdr_t *hdr = udata->hdr;       /* Fractal heap header */
@@ -963,26 +963,26 @@ H5HF_sect_single_merge(H5FS_section_info_t *_sect1, H5FS_section_info_t *_sect2,
 
     /* Check arguments. */
     HDassert(sect1);
-    HDassert(sect1->sect_info.type == H5HF_FSPACE_SECT_SINGLE);
+    HDassert((*sect1)->sect_info.type == H5HF_FSPACE_SECT_SINGLE);
     HDassert(sect2);
     HDassert(sect2->sect_info.type == H5HF_FSPACE_SECT_SINGLE);
-    HDassert(H5F_addr_eq(sect1->sect_info.addr + sect1->sect_info.size, sect2->sect_info.addr));
+    HDassert(H5F_addr_eq((*sect1)->sect_info.addr + (*sect1)->sect_info.size, sect2->sect_info.addr));
 
     /* Add second section's size to first section */
-    sect1->sect_info.size += sect2->sect_info.size;
+    (*sect1)->sect_info.size += sect2->sect_info.size;
 
     /* Get rid of second section */
     if(H5HF_sect_single_free((H5FS_section_info_t *)sect2) < 0)
         HGOTO_ERROR(H5E_HEAP, H5E_CANTRELEASE, FAIL, "can't free section node")
 
     /* Check to see if we should revive first section */
-    if(sect1->sect_info.state != H5FS_SECT_LIVE)
-        if(H5HF_sect_single_revive(hdr, dxpl_id, sect1) < 0)
+    if((*sect1)->sect_info.state != H5FS_SECT_LIVE)
+        if(H5HF_sect_single_revive(hdr, dxpl_id, (*sect1)) < 0)
             HGOTO_ERROR(H5E_HEAP, H5E_CANTINIT, FAIL, "can't revive single free section")
 
     /* Check if single section covers entire direct block it's in */
     /* (converts to row section possibly) */
-    if(H5HF_sect_single_full_dblock(hdr, dxpl_id, sect1) < 0)
+    if(H5HF_sect_single_full_dblock(hdr, dxpl_id, (*sect1)) < 0)
         HGOTO_ERROR(H5E_HEAP, H5E_CANTCONVERT, FAIL, "can't check/convert single section")
 
 done:
@@ -1771,10 +1771,10 @@ done:
  *-------------------------------------------------------------------------
  */
 static herr_t
-H5HF_sect_row_merge(H5FS_section_info_t *_sect1, H5FS_section_info_t *_sect2,
+H5HF_sect_row_merge(H5FS_section_info_t **_sect1, H5FS_section_info_t *_sect2,
     void *_udata)
 {
-    H5HF_free_section_t *sect1 = (H5HF_free_section_t *)_sect1;   /* Fractal heap free section */
+    H5HF_free_section_t **sect1 = (H5HF_free_section_t **)_sect1;   /* Fractal heap free section */
     H5HF_free_section_t *sect2 = (H5HF_free_section_t *)_sect2;   /* Fractal heap free section */
     H5HF_sect_add_ud_t *udata = (H5HF_sect_add_ud_t *)_udata;   /* User callback data */
     H5HF_hdr_t *hdr = udata->hdr;       /* Fractal heap header */
@@ -1785,7 +1785,7 @@ H5HF_sect_row_merge(H5FS_section_info_t *_sect1, H5FS_section_info_t *_sect2,
 
     /* Check arguments. */
     HDassert(sect1);
-    HDassert(sect1->sect_info.type == H5HF_FSPACE_SECT_FIRST_ROW);
+    HDassert((*sect1)->sect_info.type == H5HF_FSPACE_SECT_FIRST_ROW);
     HDassert(sect2);
     HDassert(sect2->sect_info.type == H5HF_FSPACE_SECT_FIRST_ROW);
 
@@ -1802,8 +1802,8 @@ H5HF_sect_row_merge(H5FS_section_info_t *_sect1, H5FS_section_info_t *_sect2,
     } /* end if */
     else {
         /* Check to see if we should revive first section */
-        if(sect1->sect_info.state != H5FS_SECT_LIVE)
-            if(H5HF_sect_row_revive(hdr, dxpl_id, sect1) < 0)
+        if((*sect1)->sect_info.state != H5FS_SECT_LIVE)
+            if(H5HF_sect_row_revive(hdr, dxpl_id, (*sect1)) < 0)
                 HGOTO_ERROR(H5E_HEAP, H5E_CANTINIT, FAIL, "can't revive single free section")
 
         /* Check to see if we should revive second section */
@@ -1812,7 +1812,7 @@ H5HF_sect_row_merge(H5FS_section_info_t *_sect1, H5FS_section_info_t *_sect2,
                 HGOTO_ERROR(H5E_HEAP, H5E_CANTINIT, FAIL, "can't revive single free section")
 
         /* Merge rows' underlying indirect sections together */
-        if(H5HF_sect_indirect_merge_row(hdr, dxpl_id, sect1, sect2) < 0)
+        if(H5HF_sect_indirect_merge_row(hdr, dxpl_id, (*sect1), sect2) < 0)
             HGOTO_ERROR(H5E_HEAP, H5E_CANTMERGE, FAIL, "can't merge underlying indirect sections")
     } /* end else */
 
diff --git a/src/H5MF.c b/src/H5MF.c
index 36b9386..358e326 100644
--- a/src/H5MF.c
+++ b/src/H5MF.c
@@ -29,6 +29,7 @@
 /****************/
 
 #define H5F_FRIEND		/*suppress error about including H5Fpkg	  */
+#define H5FS_FRIEND		/*suppress error about including H5Fpkg	  */
 #include "H5MFmodule.h"         /* This source code file is part of the H5MF module */
 
 
@@ -38,6 +39,7 @@
 #include "H5private.h"		/* Generic Functions			*/
 #include "H5Eprivate.h"		/* Error handling		  	*/
 #include "H5Fpkg.h"             /* File access				*/
+#include "H5FSpkg.h"            /* File access              */
 #include "H5Iprivate.h"		/* IDs			  		*/
 #include "H5MFpkg.h"		/* File memory management		*/
 #include "H5VMprivate.h"	/* Vectors and arrays 			*/
@@ -50,11 +52,6 @@
 #define H5MF_FSPACE_SHRINK      80              /* Percent of "normal" size to shrink serialized free space size */
 #define H5MF_FSPACE_EXPAND      120             /* Percent of "normal" size to expand serialized free space size */
 
-/* Map an allocation request type to a free list */
-#define H5MF_ALLOC_TO_FS_TYPE(F, T)      ((H5FD_MEM_DEFAULT == (F)->shared->fs_type_map[T]) \
-    ? (T) : (F)->shared->fs_type_map[T])
-
-
 /******************/
 /* Local Typedefs */
 /******************/
@@ -84,11 +81,24 @@ typedef struct {
 /********************/
 
 /* Allocator routines */
-static herr_t H5MF_alloc_create(H5F_t *f, hid_t dxpl_id, H5FD_mem_t type);
-static herr_t H5MF__alloc_close(H5F_t *f, hid_t dxpl_id, H5FD_mem_t type);
-static herr_t H5MF__close_delete(H5F_t *f, hid_t dxpl_id, H5P_genplist_t **dxpl);
+static haddr_t H5MF__alloc_pagefs(H5F_t *f, H5FD_mem_t alloc_type, hid_t dxpl_id, hsize_t size);
+
+/* "File closing" routines */
+static herr_t H5MF__close_aggrfs(H5F_t *f, hid_t dxpl_id);
+static herr_t H5MF__close_pagefs(H5F_t *f, hid_t dxpl_id);
 static herr_t H5MF__close_shrink_eoa(H5F_t *f, hid_t dxpl_id);
 
+/* General routines */
+static herr_t H5MF__get_free_sects(H5F_t *f, hid_t dxpl_id, H5FS_t *fspace, H5MF_sect_iter_ud_t *sect_udata, size_t *nums);
+static hbool_t H5MF__fsm_type_is_self_referential(H5F_t *f, H5F_mem_page_t fsm_type);
+static hbool_t H5MF__fsm_is_self_referential(H5F_t *f, H5FS_t *fspace);
+
+/* Free-space type manager routines */
+static herr_t H5MF__create_fstype(H5F_t *f, hid_t dxpl_id, H5F_mem_page_t type);
+static herr_t H5MF__close_fstype(H5F_t *f, hid_t dxpl_id, H5F_mem_page_t type);
+static herr_t H5MF__delete_fstype(H5F_t *f, hid_t dxpl_id, H5F_mem_page_t type);
+static herr_t H5MF__close_delete_fstype(H5F_t *f, hid_t dxpl_id, H5F_mem_page_t type);
+
 
 /*********************/
 /* Package Variables */
@@ -223,10 +233,54 @@ done:
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5MF__alloc_open
+ * Function:    H5MF_alloc_to_fs_type
+ *
+ * Purpose:     Map "alloc_type" to the free-space manager type
+ *
+ * Return:      Success:        non-negative
+ *              Failure:        negative
+ *
+ * Programmer: Vailin Choi; Nov 2016
+ *
+ *-------------------------------------------------------------------------
+ */
+void
+H5MF_alloc_to_fs_type(H5F_t *f, H5FD_mem_t alloc_type, hsize_t size, H5F_mem_page_t *fs_type)
+{
+    FUNC_ENTER_NOAPI_NOINIT_NOERR
+
+    HDassert(f);
+    HDassert(fs_type);
+
+    if(H5F_PAGED_AGGR(f)) { /* paged aggregation */
+        if(size >= f->shared->fs_page_size) {
+            if(H5F_HAS_FEATURE(f, H5FD_FEAT_PAGED_AGGR)) { /* multi or split driver */
+                /* For non-contiguous address space, map to large size free-space manager for each alloc_type */
+                if(H5FD_MEM_DEFAULT == f->shared->fs_type_map[alloc_type]) 
+                    *fs_type = (H5F_mem_page_t) (alloc_type + (H5FD_MEM_NTYPES - 1));
+                else
+                    *fs_type = (H5F_mem_page_t) (f->shared->fs_type_map[alloc_type] + (H5FD_MEM_NTYPES - 1));
+            } /* end if */
+            else
+                /* For contiguous address space, map to generic large size free-space manager */
+                *fs_type = H5F_MEM_PAGE_GENERIC; /* H5F_MEM_PAGE_SUPER */
+        } /* end if */
+        else
+            *fs_type = (H5F_mem_page_t)H5MF_ALLOC_TO_FS_AGGR_TYPE(f, alloc_type);
+    } /* end if */
+    else /* non-paged aggregation */
+        *fs_type = (H5F_mem_page_t)H5MF_ALLOC_TO_FS_AGGR_TYPE(f, alloc_type);
+
+    FUNC_LEAVE_NOAPI_VOID
+} /* end H5MF_alloc_to_fs_type() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:	H5MF_open_fstype
  *
  * Purpose:	Open an existing free space manager of TYPE for file by
- *		creating a free-space structure
+ *          creating a free-space structure.
+ *          Note that TYPE can be H5F_mem_page_t or H5FD_mem_t enum types.
  *
  * Return:	Success:	non-negative
  *		Failure:	negative
@@ -238,31 +292,48 @@ done:
  *-------------------------------------------------------------------------
  */
 herr_t
-H5MF__alloc_open(H5F_t *f, hid_t dxpl_id, H5FD_mem_t type)
+H5MF_open_fstype(H5F_t *f, hid_t dxpl_id, H5F_mem_page_t type)
 {
     const H5FS_section_class_t *classes[] = { /* Free space section classes implemented for file */
-        H5MF_FSPACE_SECT_CLS_SIMPLE};
-    H5P_genplist_t *dxpl = NULL;        /* DXPL for setting ring */
-    H5AC_ring_t fsm_ring;               /* Free space manager ring */
-    H5AC_ring_t orig_ring = H5AC_RING_INV;      /* Original ring value */
-    hbool_t reset_ring = FALSE;         /* Whether the ring was set */
-    herr_t ret_value = SUCCEED;         /* Return value */
+        H5MF_FSPACE_SECT_CLS_SIMPLE,
+        H5MF_FSPACE_SECT_CLS_SMALL,
+        H5MF_FSPACE_SECT_CLS_LARGE };
+    hsize_t alignment;                      /* Alignment to use */
+    hsize_t threshold;                      /* Threshold to use */
+    H5P_genplist_t *dxpl = NULL;            /* DXPL for setting ring */
+    H5AC_ring_t orig_ring = H5AC_RING_INV;  /* Original ring value */
+    H5AC_ring_t fsm_ring = H5AC_RING_INV;   /* ring of fsm */
+    hbool_t reset_ring = FALSE;             /* Whether the ring was set */
+    herr_t ret_value = SUCCEED;             /* Return value */
 
-    FUNC_ENTER_NOAPI_NOINIT_TAG(dxpl_id, H5AC__FREESPACE_TAG, FAIL)
+    FUNC_ENTER_NOAPI_TAG(dxpl_id, H5AC__FREESPACE_TAG, FAIL)
 
     /*
      * Check arguments.
      */
     HDassert(f);
+    if(H5F_PAGED_AGGR(f))
+        HDassert(type < H5F_MEM_PAGE_NTYPES);
+    else {
+        HDassert((H5FD_mem_t)type < H5FD_MEM_NTYPES);
+        HDassert((H5FD_mem_t)type != H5FD_MEM_NOLIST);
+    } /* end else */
     HDassert(f->shared);
-    HDassert(type != H5FD_MEM_NOLIST);
     HDassert(H5F_addr_defined(f->shared->fs_addr[type]));
     HDassert(f->shared->fs_state[type] == H5F_FS_STATE_CLOSED);
-    HDassert(type == H5MF_ALLOC_TO_FS_TYPE(f, type));
+
+    /* Set up the aligment and threshold to use depending on the manager type */
+    if(H5F_PAGED_AGGR(f)) {
+        alignment = (type == H5F_MEM_PAGE_GENERIC) ? f->shared->fs_page_size : (hsize_t)H5F_ALIGN_DEF;
+        threshold = H5F_ALIGN_THRHD_DEF;
+    } /* end if */
+    else {
+        alignment = f->shared->alignment;
+        threshold = f->shared->threshold;
+    } /* end else */
 
     /* Set the ring type in the DXPL */
-    if((type == H5MF_ALLOC_TO_FS_TYPE(f, H5FD_MEM_FSPACE_HDR))
-            || (type == H5MF_ALLOC_TO_FS_TYPE(f, H5FD_MEM_FSPACE_SINFO)))
+    if(H5MF__fsm_type_is_self_referential(f, type))
         fsm_ring = H5AC_RING_MDFSM;
     else
         fsm_ring = H5AC_RING_RDFSM;
@@ -272,7 +343,7 @@ H5MF__alloc_open(H5F_t *f, hid_t dxpl_id, H5FD_mem_t type)
 
     /* Open an existing free space structure for the file */
     if(NULL == (f->shared->fs_man[type] = H5FS_open(f, dxpl_id, f->shared->fs_addr[type],
-	    NELMTS(classes), classes, f, f->shared->alignment, f->shared->threshold)))
+	    NELMTS(classes), classes, f, alignment, threshold)))
         HGOTO_ERROR(H5E_RESOURCE, H5E_CANTINIT, FAIL, "can't initialize free space info")
 
     /* Set the state for the free space manager to "open", if it is now */
@@ -286,14 +357,15 @@ done:
             HDONE_ERROR(H5E_RESOURCE, H5E_CANTSET, FAIL, "unable to set property value")
 
     FUNC_LEAVE_NOAPI_TAG(ret_value, FAIL)
-} /* end H5MF__alloc_open() */
+} /* end H5MF_open_fstype() */
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5MF_alloc_create
+ * Function:	H5MF__create_fstype
  *
  * Purpose:	Create free space manager of TYPE for the file by creating
- *		a free-space structure
+ *          a free-space structure
+ *          Note that TYPE can be H5F_mem_page_t or H5FD_mem_t enum types.
  *
  * Return:	Success:	non-negative
  *		Failure:	negative
@@ -305,21 +377,34 @@ done:
  *-------------------------------------------------------------------------
  */
 static herr_t
-H5MF_alloc_create(H5F_t *f, hid_t dxpl_id, H5FD_mem_t type)
+H5MF__create_fstype(H5F_t *f, hid_t dxpl_id, H5F_mem_page_t type)
 {
     const H5FS_section_class_t *classes[] = { /* Free space section classes implemented for file */
-        H5MF_FSPACE_SECT_CLS_SIMPLE};
-    herr_t ret_value = SUCCEED;         /* Return value */
-    H5FS_create_t fs_create; 		/* Free space creation parameters */
+        H5MF_FSPACE_SECT_CLS_SIMPLE,
+        H5MF_FSPACE_SECT_CLS_SMALL,
+        H5MF_FSPACE_SECT_CLS_LARGE };
+    H5FS_create_t fs_create;    /* Free space creation parameters */
+    hsize_t alignment;          /* Alignment to use */
+    hsize_t threshold;			/* Threshold to use */
+    H5P_genplist_t *dxpl = NULL;            /* DXPL for setting ring */
+    H5AC_ring_t orig_ring = H5AC_RING_INV;  /* Original ring value */
+    H5AC_ring_t fsm_ring = H5AC_RING_INV;   /* ring of fsm */
+    hbool_t reset_ring = FALSE;             /* Whether the ring was set */
+    herr_t ret_value = SUCCEED;             /* Return value */
 
-    FUNC_ENTER_NOAPI_NOINIT_TAG(dxpl_id, H5AC__FREESPACE_TAG, FAIL)
+    FUNC_ENTER_STATIC_TAG(dxpl_id, H5AC__FREESPACE_TAG, FAIL)
 
     /*
      * Check arguments.
      */
     HDassert(f);
+    if(H5F_PAGED_AGGR(f))
+        HDassert(type < H5F_MEM_PAGE_NTYPES);
+    else {
+        HDassert((H5FD_mem_t)type < H5FD_MEM_NTYPES);
+        HDassert((H5FD_mem_t)type != H5FD_MEM_NOLIST);
+    } /* end else */
     HDassert(f->shared);
-    HDassert(type != H5FD_MEM_NOLIST);
     HDassert(!H5F_addr_defined(f->shared->fs_addr[type]));
     HDassert(f->shared->fs_state[type] == H5F_FS_STATE_CLOSED);
 
@@ -330,24 +415,48 @@ H5MF_alloc_create(H5F_t *f, hid_t dxpl_id, H5FD_mem_t type)
     fs_create.max_sect_addr = 1 + H5VM_log2_gen((uint64_t)f->shared->maxaddr);
     fs_create.max_sect_size = f->shared->maxaddr;
 
-    if(NULL == (f->shared->fs_man[type] = H5FS_create(f, dxpl_id, NULL,
-	    &fs_create, NELMTS(classes), classes, f, f->shared->alignment, f->shared->threshold)))
-	HGOTO_ERROR(H5E_RESOURCE, H5E_CANTINIT, FAIL, "can't initialize free space info")
+    /* Set up alignment and threshold to use depending on TYPE */
+    if(H5F_PAGED_AGGR(f)) {
+        alignment = (type == H5F_MEM_PAGE_GENERIC) ? f->shared->fs_page_size : (hsize_t)H5F_ALIGN_DEF;
+        threshold = H5F_ALIGN_THRHD_DEF;
+    } /* end if */
+    else {
+        alignment = f->shared->alignment;
+        threshold = f->shared->threshold;
+    } /* end else */
 
+    /* Set the ring type in the DXPL */
+    if(H5MF__fsm_type_is_self_referential(f, type))
+        fsm_ring = H5AC_RING_MDFSM;
+    else
+        fsm_ring = H5AC_RING_RDFSM;
+    if(H5AC_set_ring(dxpl_id, fsm_ring, &dxpl, &orig_ring) < 0)
+        HGOTO_ERROR(H5E_RESOURCE, H5E_CANTSET, FAIL, "unable to set ring value")
+    reset_ring = TRUE;
+
+    if(NULL == (f->shared->fs_man[type] = H5FS_create(f, dxpl_id, NULL,
+	    &fs_create, NELMTS(classes), classes, f, alignment, threshold)))
+        HGOTO_ERROR(H5E_RESOURCE, H5E_CANTINIT, FAIL, "can't initialize free space info")
 
     /* Set the state for the free space manager to "open", if it is now */
     if(f->shared->fs_man[type])
         f->shared->fs_state[type] = H5F_FS_STATE_OPEN;
 
 done:
+    /* Reset the ring in the DXPL */
+    if(reset_ring)
+        if(H5AC_reset_ring(dxpl, orig_ring) < 0)
+            HDONE_ERROR(H5E_RESOURCE, H5E_CANTSET, FAIL, "unable to set property value")
+
     FUNC_LEAVE_NOAPI_TAG(ret_value, FAIL)
-} /* end H5MF_alloc_create() */
+} /* end H5MF__create_fstype() */
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5MF__alloc_start
+ * Function:	H5MF_start_fstype
  *
- * Purpose:	Open or create a free space manager of a given type
+ * Purpose:	Open or create a free space manager of a given TYPE.
+ *          Note that TYPE can be H5F_mem_page_t or H5FD_mem_t enum types.
  *
  * Return:	Success:	non-negative
  *		Failure:	negative
@@ -359,40 +468,123 @@ done:
  *-------------------------------------------------------------------------
  */
 herr_t
-H5MF__alloc_start(H5F_t *f, hid_t dxpl_id, H5FD_mem_t type)
+H5MF_start_fstype(H5F_t *f, hid_t dxpl_id, H5F_mem_page_t type)
 {
     herr_t ret_value = SUCCEED;         /* Return value */
 
-    FUNC_ENTER_NOAPI_NOINIT
+    FUNC_ENTER_NOAPI_TAG(dxpl_id, H5AC__FREESPACE_TAG, FAIL)
 
     /*
      * Check arguments.
      */
     HDassert(f);
     HDassert(f->shared);
-    HDassert(type != H5FD_MEM_NOLIST);
+    if(H5F_PAGED_AGGR(f))
+        HDassert(type < H5F_MEM_PAGE_NTYPES);
+    else {
+        HDassert((H5FD_mem_t)type < H5FD_MEM_NTYPES);
+        HDassert((H5FD_mem_t)type != H5FD_MEM_NOLIST);
+    } /* end else */
 
     /* Check if the free space manager exists already */
     if(H5F_addr_defined(f->shared->fs_addr[type])) {
         /* Open existing free space manager */
-        if(H5MF__alloc_open(f, dxpl_id, type) < 0)
+        if(H5MF_open_fstype(f, dxpl_id, type) < 0)
             HGOTO_ERROR(H5E_RESOURCE, H5E_CANTOPENOBJ, FAIL, "can't initialize file free space")
     } /* end if */
     else {
         /* Create new free space manager */
-        if(H5MF_alloc_create(f, dxpl_id, type) < 0)
+        if(H5MF__create_fstype(f, dxpl_id, type) < 0)
             HGOTO_ERROR(H5E_RESOURCE, H5E_CANTCREATE, FAIL, "can't initialize file free space")
     } /* end else */
 
 done:
-    FUNC_LEAVE_NOAPI(ret_value)
-} /* end H5MF__alloc_start() */
+    FUNC_LEAVE_NOAPI_TAG(ret_value, FAIL)
+} /* end H5MF_start_fstype() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:    H5MF__delete_fstype
+ *
+ * Purpose:     Delete the free-space manager as specified by TYPE.
+ *              Note that TYPE can be H5F_mem_page_t or H5FD_mem_t enum types.
+ *
+ * Return:      Success:        non-negative
+ *              Failure:        negative
+ *
+ * Programmer: 	Vailin Choi; April 2013
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+H5MF__delete_fstype(H5F_t *f, hid_t dxpl_id, H5F_mem_page_t type)
+{
+    H5P_genplist_t *dxpl = NULL;        /* DXPL for setting ring */
+    H5AC_ring_t orig_ring = H5AC_RING_INV;      /* Original ring value */
+    H5AC_ring_t fsm_ring = H5AC_RING_INV;       /* ring of fsm */
+    hbool_t reset_ring = FALSE;         /* Whether the ring was set */
+    haddr_t tmp_fs_addr;       	        /* Temporary holder for free space manager address */
+    herr_t ret_value = SUCCEED;	        /* Return value */
+
+    FUNC_ENTER_STATIC_TAG(dxpl_id, H5AC__FREESPACE_TAG, FAIL)
+
+    /* check args */
+    HDassert(f);
+    if(H5F_PAGED_AGGR(f))
+        HDassert(type < H5F_MEM_PAGE_NTYPES);
+    else
+        HDassert((H5FD_mem_t)type < H5FD_MEM_NTYPES);
+    HDassert(H5F_addr_defined(f->shared->fs_addr[type]));
+
+    /* Put address into temporary variable and reset it */
+    /* (Avoids loopback in file space freeing routine) */
+    tmp_fs_addr = f->shared->fs_addr[type];
+    f->shared->fs_addr[type] = HADDR_UNDEF;
+
+    /* Shift to "deleting" state, to make certain we don't track any
+     *  file space freed as a result of deleting the free space manager.
+     */
+    f->shared->fs_state[type] = H5F_FS_STATE_DELETING;
+
+    /* Set the ring type in the DXPL */
+    if(H5MF__fsm_type_is_self_referential(f, type))
+        fsm_ring = H5AC_RING_MDFSM;
+    else
+        fsm_ring = H5AC_RING_RDFSM;
+    if(H5AC_set_ring(dxpl_id, fsm_ring, &dxpl, &orig_ring) < 0)
+        HGOTO_ERROR(H5E_RESOURCE, H5E_CANTSET, FAIL, "unable to set ring value")
+    reset_ring = TRUE;
+
+#ifdef H5MF_ALLOC_DEBUG_MORE
+HDfprintf(stderr, "%s: Before deleting free space manager\n", FUNC);
+#endif /* H5MF_ALLOC_DEBUG_MORE */
+
+    /* Delete free space manager for this type */
+    if(H5FS_delete(f, dxpl_id, tmp_fs_addr) < 0)
+        HGOTO_ERROR(H5E_RESOURCE, H5E_CANTFREE, FAIL, "can't delete free space manager")
+
+    /* Shift [back] to closed state */
+    HDassert(f->shared->fs_state[type] == H5F_FS_STATE_DELETING);
+    f->shared->fs_state[type] = H5F_FS_STATE_CLOSED;
+
+    /* Sanity check that the free space manager for this type wasn't started up again */
+    HDassert(!H5F_addr_defined(f->shared->fs_addr[type]));
+
+done:
+    /* Reset the ring in the DXPL */
+    if(reset_ring)
+        if(H5AC_reset_ring(dxpl, orig_ring) < 0)
+            HDONE_ERROR(H5E_RESOURCE, H5E_CANTSET, FAIL, "unable to set property value")
+
+    FUNC_LEAVE_NOAPI_TAG(ret_value, FAIL)
+} /* end H5MF__delete_fstype() */
 
 
 /*-------------------------------------------------------------------------
- * Function:    H5MF__alloc_close
+ * Function:    H5MF__close_fstype
  *
- * Purpose:     Close an existing free space manager of TYPE for file
+ * Purpose:     Close the free space manager of TYPE for file
+ *              Note that TYPE can be H5F_mem_page_t or H5FD_mem_t enum types.
  *
  * Return:      Success:        non-negative
  *              Failure:        negative
@@ -402,7 +594,7 @@ done:
  *-------------------------------------------------------------------------
  */
 static herr_t
-H5MF__alloc_close(H5F_t *f, hid_t dxpl_id, H5FD_mem_t type)
+H5MF__close_fstype(H5F_t *f, hid_t dxpl_id, H5F_mem_page_t type)
 {
     herr_t ret_value = SUCCEED;         /* Return value */
 
@@ -412,11 +604,18 @@ H5MF__alloc_close(H5F_t *f, hid_t dxpl_id, H5FD_mem_t type)
      * Check arguments.
      */
     HDassert(f);
+    if(H5F_PAGED_AGGR(f))
+        HDassert(type < H5F_MEM_PAGE_NTYPES);
+    else
+        HDassert((H5FD_mem_t)type < H5FD_MEM_NTYPES);
     HDassert(f->shared);
-    HDassert(type != H5FD_MEM_NOLIST);
     HDassert(f->shared->fs_man[type]);
     HDassert(f->shared->fs_state[type] != H5F_FS_STATE_CLOSED);
 
+#ifdef H5MF_ALLOC_DEBUG_MORE
+HDfprintf(stderr, "%s: Before closing free space manager\n", FUNC);
+#endif /* H5MF_ALLOC_DEBUG_MORE */
+
     /* Close an existing free space structure for the file */
     if(H5FS_close(f, dxpl_id, f->shared->fs_man[type]) < 0)
         HGOTO_ERROR(H5E_RESOURCE, H5E_CANTRELEASE, FAIL, "can't release free space info")
@@ -425,7 +624,158 @@ H5MF__alloc_close(H5F_t *f, hid_t dxpl_id, H5FD_mem_t type)
 
 done:
     FUNC_LEAVE_NOAPI_TAG(ret_value, FAIL)
-} /* end H5MF__alloc_close() */
+} /* end H5MF__close_fstype() */
+
+
+
+/*-------------------------------------------------------------------------
+ * Function:    H5MF_add_sect
+ *
+ * Purpose:	    To add a section to the specified free-space manager.
+ *
+ * Return:      Success:        non-negative
+ *              Failure:        negative
+ *
+ * Programmer:  Vailin Choi; April 2013
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5MF_add_sect(H5F_t *f, H5FD_mem_t alloc_type, hid_t dxpl_id, H5FS_t *fspace, H5MF_free_section_t *node)
+{
+    H5P_genplist_t *dxpl = NULL;            /* DXPL for setting ring */
+    H5AC_ring_t orig_ring = H5AC_RING_INV;  /* Original ring value */
+    H5AC_ring_t fsm_ring = H5AC_RING_INV;   /* ring of fsm */
+    H5MF_sect_ud_t udata;		            /* User data for callback */
+    H5F_mem_page_t  fs_type;                /* Free space type (mapped from allocation type) */
+
+    herr_t ret_value = SUCCEED; 	        /* Return value */
+
+    FUNC_ENTER_NOAPI_TAG(dxpl_id, H5AC__FREESPACE_TAG, FAIL)
+
+    HDassert(f);
+    HDassert(fspace);
+    HDassert(node);
+
+    H5MF_alloc_to_fs_type(f, alloc_type, node->sect_info.size, &fs_type);
+
+    /* Construct user data for callbacks */
+    udata.f = f;
+    udata.dxpl_id = dxpl_id;
+    udata.alloc_type = alloc_type;
+    udata.allow_sect_absorb = TRUE;
+    udata.allow_eoa_shrink_only = FALSE;
+
+    /* Set the ring type in the DXPL */
+    if(H5MF__fsm_is_self_referential(f, fspace))
+        fsm_ring = H5AC_RING_MDFSM;
+    else
+        fsm_ring = H5AC_RING_RDFSM;
+    if(H5AC_set_ring(dxpl_id, fsm_ring, &dxpl, &orig_ring) < 0)
+        HGOTO_ERROR(H5E_RESOURCE, H5E_CANTSET, FAIL, "unable to set ring value")
+
+#ifdef H5MF_ALLOC_DEBUG_MORE
+HDfprintf(stderr, "%s: adding node, node->sect_info.addr = %a, node->sect_info.size = %Hu\n", FUNC, node->sect_info.addr, node->sect_info.size);
+#endif /* H5MF_ALLOC_DEBUG_MORE */
+    /* Add the section */
+    if(H5FS_sect_add(f, dxpl_id, fspace, (H5FS_section_info_t *)node, H5FS_ADD_RETURNED_SPACE, &udata) < 0)
+        HGOTO_ERROR(H5E_RESOURCE, H5E_CANTINSERT, FAIL, "can't re-add section to file free space")
+
+done:
+    /* Reset the ring in the DXPL */
+    if(H5AC_reset_ring(dxpl, orig_ring) < 0)
+        HDONE_ERROR(H5E_RESOURCE, H5E_CANTSET, FAIL, "unable to set property value")
+    FUNC_LEAVE_NOAPI_TAG(ret_value, FAIL)
+} /* end H5MF_add_sect() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:    H5MF_find_sect
+ *
+ * Purpose:	To find a section from the specified free-space manager to fulfill the request.
+ *		    If found, re-add the left-over space back to the manager.
+ *
+ * Return:	TRUE if a section is found to fulfill the request
+ *		    FALSE if not
+ *
+ * Programmer:  Vailin Choi; April 2013
+ *
+ *-------------------------------------------------------------------------
+ */
+htri_t
+H5MF_find_sect(H5F_t *f, H5FD_mem_t alloc_type, hid_t dxpl_id, hsize_t size, H5FS_t *fspace, haddr_t *addr)
+{
+    H5P_genplist_t *dxpl = NULL;            /* DXPL for setting ring */
+    H5AC_ring_t orig_ring = H5AC_RING_INV;  /* Original ring value */
+    H5AC_ring_t fsm_ring = H5AC_RING_INV;   /* ring of fsm */
+    H5MF_free_section_t *node;              /* Free space section pointer */
+    hbool_t reset_ring = FALSE;             /* Whether the ring was set */
+    htri_t ret_value = FAIL;      	    /* Whether an existing free list node was found */
+
+    FUNC_ENTER_NOAPI_TAG(dxpl_id, H5AC__FREESPACE_TAG, FAIL)
+
+    HDassert(f);
+    HDassert(fspace);
+
+    /* Set the ring type in the DXPL */
+    if(H5MF__fsm_is_self_referential(f, fspace))
+        fsm_ring = H5AC_RING_MDFSM;
+    else
+        fsm_ring = H5AC_RING_RDFSM;
+    if(H5AC_set_ring(dxpl_id, fsm_ring, &dxpl, &orig_ring) < 0)
+        HGOTO_ERROR(H5E_RESOURCE, H5E_CANTSET, FAIL, "unable to set ring value")
+    reset_ring = TRUE;
+
+    /* Try to get a section from the free space manager */
+    if((ret_value = H5FS_sect_find(f, dxpl_id, fspace, size, (H5FS_section_info_t **)&node)) < 0)
+        HGOTO_ERROR(H5E_RESOURCE, H5E_CANTALLOC, FAIL, "error locating free space in file")
+
+#ifdef H5MF_ALLOC_DEBUG_MORE
+HDfprintf(stderr, "%s: section found = %t\n", FUNC, ret_value);
+#endif /* H5MF_ALLOC_DEBUG_MORE */
+
+    /* Check for actually finding section */
+    if(ret_value) {
+        /* Sanity check */
+        HDassert(node);
+
+        /* Retrieve return value */
+        if(addr)
+            *addr = node->sect_info.addr;
+
+        /* Check for eliminating the section */
+        if(node->sect_info.size == size) {
+#ifdef H5MF_ALLOC_DEBUG_MORE
+HDfprintf(stderr, "%s: freeing node\n", FUNC);
+#endif /* H5MF_ALLOC_DEBUG_MORE */
+
+            /* Free section node */
+            if(H5MF_sect_free((H5FS_section_info_t *)node) < 0)
+                HGOTO_ERROR(H5E_RESOURCE, H5E_CANTRELEASE, FAIL, "can't free simple section node")
+        } /* end if */
+        else {
+            /* Adjust information for section */
+            node->sect_info.addr += size;
+            node->sect_info.size -= size;
+
+#ifdef H5MF_ALLOC_DEBUG_MORE
+HDfprintf(stderr, "%s: re-adding node, node->sect_info.size = %Hu\n", FUNC, node->sect_info.size);
+#endif /* H5MF_ALLOC_DEBUG_MORE */
+
+            /* Re-add the section to the free-space manager */
+            if(H5MF_add_sect(f, alloc_type, dxpl_id, fspace, node) < 0)
+                HGOTO_ERROR(H5E_RESOURCE, H5E_CANTINSERT, FAIL, "can't re-add section to file free space")
+        } /* end else */
+    } /* end if */
+
+done:
+    /* Reset the ring in the DXPL */
+    if(reset_ring)
+        if(H5AC_reset_ring(dxpl, orig_ring) < 0)
+            HDONE_ERROR(H5E_RESOURCE, H5E_CANTSET, FAIL, "unable to set property value")
+
+    FUNC_LEAVE_NOAPI_TAG(ret_value, FAIL)
+} /* end H5MF_find_sect() */
 
 
 /*-------------------------------------------------------------------------
@@ -451,7 +801,7 @@ H5MF_alloc(H5F_t *f, H5FD_mem_t alloc_type, hid_t dxpl_id, hsize_t size)
     H5P_genplist_t *dxpl = NULL;        /* DXPL for setting ring */
     H5AC_ring_t fsm_ring = H5AC_RING_INV;       /* free space manager ring */
     H5AC_ring_t orig_ring = H5AC_RING_INV;      /* Original ring value */
-    H5FD_mem_t  fs_type;                /* Free space type (mapped from allocation type) */
+    H5F_mem_page_t  fs_type;            /* Free space type (mapped from allocation type) */
     hbool_t reset_ring = FALSE;         /* Whether the ring was set */
     haddr_t ret_value = HADDR_UNDEF;    /* Return value */
 
@@ -466,12 +816,20 @@ HDfprintf(stderr, "%s: alloc_type = %u, size = %Hu\n", FUNC, (unsigned)alloc_typ
     HDassert(f->shared->lf);
     HDassert(size > 0);
 
-    /* Get free space type from allocation type */
-    fs_type = H5MF_ALLOC_TO_FS_TYPE(f, alloc_type);
+    if(f->shared->first_alloc_dealloc) {
+        HDassert(! H5AC_cache_image_pending(f));
+        if(H5MF_tidy_self_referential_fsm_hack(f, dxpl_id) < 0)
+            HGOTO_ERROR(H5E_RESOURCE, H5E_CANTFREE, HADDR_UNDEF, "tidy of self referential fsm hack failed")
+    } /* end if */
+
+    H5MF_alloc_to_fs_type(f, alloc_type, size, &fs_type);
+
+#ifdef H5MF_ALLOC_DEBUG_MORE
+HDfprintf(stderr, "%s: Check 1.0\n", FUNC);
+#endif /* H5MF_ALLOC_DEBUG_MORE */
 
     /* Set the ring type in the DXPL */
-    if((fs_type == H5MF_ALLOC_TO_FS_TYPE(f, H5FD_MEM_FSPACE_HDR))
-            || (fs_type == H5MF_ALLOC_TO_FS_TYPE(f, H5FD_MEM_FSPACE_SINFO)))
+    if(H5MF__fsm_type_is_self_referential(f, fs_type))
         fsm_ring = H5AC_RING_MDFSM;
     else
         fsm_ring = H5AC_RING_RDFSM;
@@ -481,74 +839,46 @@ HDfprintf(stderr, "%s: alloc_type = %u, size = %Hu\n", FUNC, (unsigned)alloc_typ
 
     /* Check if we are using the free space manager for this file */
     if(H5F_HAVE_FREE_SPACE_MANAGER(f)) {
+        /* We are about to change the contents of the free space manager --
+         * notify metadata cache that the associated fsm ring is
+         * unsettled
+         */
+        if(H5AC_unsettle_ring(f, fsm_ring) < 0)
+            HGOTO_ERROR(H5E_RESOURCE, H5E_SYSTEM, HADDR_UNDEF, "attempt to notify cache that ring is unsettled failed")
+
         /* Check if the free space manager for the file has been initialized */
-        if(!f->shared->fs_man[fs_type] && H5F_addr_defined(f->shared->fs_addr[fs_type]))
-            if(H5MF__alloc_open(f, dxpl_id, fs_type) < 0)
+        if(!f->shared->fs_man[fs_type] && H5F_addr_defined(f->shared->fs_addr[fs_type])) {
+            /* Open the free-space manager */
+            if(H5MF_open_fstype(f, dxpl_id, fs_type) < 0)
                 HGOTO_ERROR(H5E_RESOURCE, H5E_CANTOPENOBJ, HADDR_UNDEF, "can't initialize file free space")
+            HDassert(f->shared->fs_man[fs_type]);
+        } /* end if */
 
         /* Search for large enough space in the free space manager */
-        if(f->shared->fs_man[fs_type]) {
-            H5MF_free_section_t *node;      /* Free space section pointer */
-            htri_t node_found = FALSE;      /* Whether an existing free list node was found */
-
-            /* Try to get a section from the free space manager */
-            if((node_found = H5FS_sect_find(f, dxpl_id, f->shared->fs_man[fs_type], size, (H5FS_section_info_t **)&node)) < 0)
-                HGOTO_ERROR(H5E_RESOURCE, H5E_CANTALLOC, HADDR_UNDEF, "error locating free space in file")
-#ifdef H5MF_ALLOC_DEBUG_MORE
-HDfprintf(stderr, "%s: Check 1.5, node_found = %t\n", FUNC, node_found);
-#endif /* H5MF_ALLOC_DEBUG_MORE */
-
-            /* Check for actually finding section */
-            if(node_found) {
-                /* Sanity check */
-                HDassert(node);
-
-                /* Retrieve return value */
-                ret_value = node->sect_info.addr;
-
-                /* Check for eliminating the section */
-                if(node->sect_info.size == size) {
-#ifdef H5MF_ALLOC_DEBUG_MORE
-HDfprintf(stderr, "%s: Check 1.6, freeing node\n", FUNC);
-#endif /* H5MF_ALLOC_DEBUG_MORE */
-                    /* Free section node */
-                    if(H5MF_sect_simple_free((H5FS_section_info_t *)node) < 0)
-                        HGOTO_ERROR(H5E_RESOURCE, H5E_CANTRELEASE, HADDR_UNDEF, "can't free simple section node")
-                } /* end if */
-                else {
-                    H5MF_sect_ud_t udata;               /* User data for callback */
-
-                    /* Adjust information for section */
-                    node->sect_info.addr += size;
-                    node->sect_info.size -= size;
-
-                    /* Construct user data for callbacks */
-                    udata.f = f;
-                    udata.dxpl_id = dxpl_id;
-                    udata.alloc_type = alloc_type;
-                    udata.allow_sect_absorb = TRUE;
-		    udata.allow_eoa_shrink_only = FALSE; 
+        if(f->shared->fs_man[fs_type])
+            if(H5MF_find_sect(f, alloc_type, dxpl_id, size, f->shared->fs_man[fs_type], &ret_value) < 0)
+                HGOTO_ERROR(H5E_RESOURCE, H5E_CANTALLOC, HADDR_UNDEF, "error locating a node")
+    } /* end if */
 
+    /* If no space is found from the free-space manager, continue further action */
+    if(!H5F_addr_defined(ret_value)) {
 #ifdef H5MF_ALLOC_DEBUG_MORE
-HDfprintf(stderr, "%s: Check 1.7, re-adding node, node->sect_info.size = %Hu\n", FUNC, node->sect_info.size);
+HDfprintf(stderr, "%s: Check 2.0\n", FUNC);
 #endif /* H5MF_ALLOC_DEBUG_MORE */
-                    /* Re-insert section node into file's free space */
-                    if(H5FS_sect_add(f, dxpl_id, f->shared->fs_man[fs_type], (H5FS_section_info_t *)node, H5FS_ADD_RETURNED_SPACE, &udata) < 0)
-                        HGOTO_ERROR(H5E_RESOURCE, H5E_CANTINSERT, HADDR_UNDEF, "can't re-add section to file free space")
-                } /* end else */
-
-                /* Leave now */
-                HGOTO_DONE(ret_value)
-            } /* end if */
+        if(f->shared->fs_strategy == H5F_FSPACE_STRATEGY_PAGE) {
+            HDassert(f->shared->fs_page_size >= H5F_FILE_SPACE_PAGE_SIZE_MIN);
+            if(HADDR_UNDEF == (ret_value = H5MF__alloc_pagefs(f, alloc_type, dxpl_id, size)))
+                HGOTO_ERROR(H5E_RESOURCE, H5E_CANTALLOC, HADDR_UNDEF, "allocation failed from paged aggregation")
         } /* end if */
+        else { /* For non-paged aggregation, continue further action */
+            if(HADDR_UNDEF == (ret_value = H5MF_aggr_vfd_alloc(f, alloc_type, dxpl_id, size)))
+                HGOTO_ERROR(H5E_RESOURCE, H5E_CANTALLOC, HADDR_UNDEF, "allocation failed from aggr/vfd")
+        } /* end else */
+    } /* end if */
+    HDassert(H5F_addr_defined(ret_value));
 #ifdef H5MF_ALLOC_DEBUG_MORE
-HDfprintf(stderr, "%s: Check 2.0\n", FUNC);
+HDfprintf(stderr, "%s: Check 3.0\n", FUNC);
 #endif /* H5MF_ALLOC_DEBUG_MORE */
-    } /* end if */
-
-    /* Allocate from the metadata aggregator (or the VFD) */
-    if(HADDR_UNDEF == (ret_value = H5MF_aggr_vfd_alloc(f, alloc_type, dxpl_id, size)))
-	HGOTO_ERROR(H5E_RESOURCE, H5E_CANTALLOC, HADDR_UNDEF, "allocation failed from aggr/vfd")
 
 done:
     /* Reset the ring in the DXPL */
@@ -568,6 +898,146 @@ H5MF_sects_dump(f, dxpl_id, stderr);
 
 
 /*-------------------------------------------------------------------------
+ * Function:    H5MF__alloc_pagefs
+ *
+ * Purpose:     Allocate space from either the large or small free-space manager.
+ *              For "large" request:
+ *                  Allocate request from VFD
+ *                  Determine mis-aligned fragment and return the fragment to the
+ *                  appropriate manager
+ *              For "small" request:
+ *                  Allocate a page from the large manager
+ *                  Determine whether space is available from a mis-aligned fragment
+ *                  being returned to the manager
+ *              Return left-over space to the manager after fulfilling request
+ *
+ * Return:      Success:        The file address of new chunk.
+ *              Failure:        HADDR_UNDEF
+ *
+ * Programmer:  Vailin Choi; Dec 2012
+ *
+ *-------------------------------------------------------------------------
+ */
+static haddr_t
+H5MF__alloc_pagefs(H5F_t *f, H5FD_mem_t alloc_type, hid_t dxpl_id, hsize_t size)
+{
+    H5F_mem_page_t ptype;		        /* Free-space mananger type */
+    H5MF_free_section_t *node = NULL;  	/* Free space section pointer */
+    haddr_t ret_value = HADDR_UNDEF; 	/* Return value */
+
+    FUNC_ENTER_STATIC_TAG(dxpl_id, H5AC__FREESPACE_TAG, HADDR_UNDEF)
+
+#ifdef H5MF_ALLOC_DEBUG
+HDfprintf(stderr, "%s: alloc_type = %u, size = %Hu\n", FUNC, (unsigned)alloc_type, size);
+#endif /* H5MF_ALLOC_DEBUG */
+
+    H5MF_alloc_to_fs_type(f, alloc_type, size, &ptype);
+
+    switch(ptype) {
+	    case H5F_MEM_PAGE_GENERIC:  
+	    case H5F_MEM_PAGE_LARGE_BTREE:
+	    case H5F_MEM_PAGE_LARGE_DRAW:
+	    case H5F_MEM_PAGE_LARGE_GHEAP:
+	    case H5F_MEM_PAGE_LARGE_LHEAP:
+	    case H5F_MEM_PAGE_LARGE_OHDR:
+        {
+            haddr_t eoa;            /* EOA for the file */
+            hsize_t frag_size = 0;  /* Fragment size */
+
+            /* Get the EOA for the file */
+            if(HADDR_UNDEF == (eoa = H5F_get_eoa(f, alloc_type)))
+                HGOTO_ERROR(H5E_RESOURCE, H5E_CANTGET, HADDR_UNDEF, "Unable to get eoa")
+            HDassert(!(eoa % f->shared->fs_page_size));
+
+            H5MF_EOA_MISALIGN(f, (eoa+size), f->shared->fs_page_size, frag_size);
+
+            /* Allocate from VFD */
+            if(HADDR_UNDEF == (ret_value = H5F_alloc(f, dxpl_id, alloc_type, size + frag_size, NULL, NULL)))
+                HGOTO_ERROR(H5E_RESOURCE, H5E_CANTALLOC, HADDR_UNDEF, "can't allocate file space")
+
+            /* If there is a mis-aligned fragment at EOA */
+            if(frag_size) {
+
+                /* Start up the free-space manager */
+                if(!(f->shared->fs_man[ptype]))
+                    if(H5MF_start_fstype(f, dxpl_id, ptype) < 0)
+                        HGOTO_ERROR(H5E_RESOURCE, H5E_CANTINIT, HADDR_UNDEF, "can't initialize file free space")
+
+                /* Create free space section for the fragment */
+                if(NULL == (node = H5MF_sect_new(H5MF_FSPACE_SECT_LARGE, ret_value + size, frag_size)))
+                    HGOTO_ERROR(H5E_RESOURCE, H5E_CANTINIT, HADDR_UNDEF, "can't initialize free space section")
+
+                /* Add the fragment to the large free-space manager */
+                if(H5MF_add_sect(f, alloc_type, dxpl_id, f->shared->fs_man[ptype], node) < 0)
+                    HGOTO_ERROR(H5E_RESOURCE, H5E_CANTINSERT, HADDR_UNDEF, "can't re-add section to file free space")
+
+                node = NULL;
+            } /* end if */
+        }
+        break;
+
+        case H5F_MEM_PAGE_META: 
+        case H5F_MEM_PAGE_DRAW:
+        case H5F_MEM_PAGE_BTREE:
+        case H5F_MEM_PAGE_GHEAP:
+        case H5F_MEM_PAGE_LHEAP:
+        case H5F_MEM_PAGE_OHDR:
+        {
+            haddr_t new_page;		/* The address for the new file size page */
+
+            /* Allocate one file space page */
+            if(HADDR_UNDEF == (new_page = H5MF_alloc(f, alloc_type, dxpl_id, f->shared->fs_page_size)))
+                HGOTO_ERROR(H5E_RESOURCE, H5E_CANTALLOC, HADDR_UNDEF, "can't allocate file space")
+
+            /* Start up the free-space manager */
+            if(!(f->shared->fs_man[ptype]))
+                if(H5MF_start_fstype(f, dxpl_id, ptype) < 0)
+                    HGOTO_ERROR(H5E_RESOURCE, H5E_CANTINIT, HADDR_UNDEF, "can't initialize file free space")
+            HDassert(f->shared->fs_man[ptype]);
+
+            if(NULL == (node = H5MF_sect_new(H5MF_FSPACE_SECT_SMALL, (new_page + size), (f->shared->fs_page_size - size))))
+                HGOTO_ERROR(H5E_RESOURCE, H5E_CANTINIT, HADDR_UNDEF, "can't initialize free space section")
+
+            /* Add the remaining space in the page to the manager */
+            if(H5MF_add_sect(f, alloc_type, dxpl_id, f->shared->fs_man[ptype], node) < 0)
+                HGOTO_ERROR(H5E_RESOURCE, H5E_CANTINSERT, HADDR_UNDEF, "can't re-add section to file free space")
+
+            node = NULL;
+
+            /* Insert the new page into the Page Buffer list of new pages so 
+               we don't read an empty page from disk */
+            if(f->shared->page_buf != NULL && H5PB_add_new_page(f, alloc_type, new_page) < 0)
+                HGOTO_ERROR(H5E_RESOURCE, H5E_CANTINSERT, HADDR_UNDEF, "can't add new page to Page Buffer new page list")
+
+            ret_value = new_page;
+        } 
+        break;
+
+        case H5F_MEM_PAGE_NTYPES:
+        case H5F_MEM_PAGE_DEFAULT:
+        default:
+            HGOTO_ERROR(H5E_RESOURCE, H5E_CANTALLOC, HADDR_UNDEF, "can't allocate file space: unrecognized type")
+            break;
+    } /* end switch */
+
+done:
+#ifdef H5MF_ALLOC_DEBUG
+HDfprintf(stderr, "%s: Leaving: ret_value = %a, size = %Hu\n", FUNC, ret_value, size);
+#endif /* H5MF_ALLOC_DEBUG */
+#ifdef H5MF_ALLOC_DEBUG_DUMP
+H5MF_sects_dump(f, dxpl_id, stderr);
+#endif /* H5MF_ALLOC_DEBUG_DUMP */
+
+    /* Release section node, if allocated and not added to section list or merged */
+    if(node)
+        if(H5MF_sect_free((H5FS_section_info_t *)node) < 0)
+            HDONE_ERROR(H5E_RESOURCE, H5E_CANTRELEASE, HADDR_UNDEF, "can't free section node")
+
+    FUNC_LEAVE_NOAPI_TAG(ret_value, HADDR_UNDEF)
+} /* end H5MF__alloc_pagefs() */
+
+
+/*-------------------------------------------------------------------------
  * Function:    H5MF_alloc_tmp
  *
  * Purpose:     Allocate temporary space in the file
@@ -646,13 +1116,13 @@ H5MF_xfree(H5F_t *f, H5FD_mem_t alloc_type, hid_t dxpl_id, haddr_t addr,
     hsize_t size)
 {
     H5F_io_info2_t fio_info;            /* I/O info for operation */
+    H5F_mem_page_t  fs_type;            /* Free space type (mapped from allocation type) */
     H5MF_free_section_t *node = NULL;   /* Free space section pointer */
-    H5MF_sect_ud_t udata;               /* User data for callback */
+    unsigned ctype;			/* section class type */
     H5P_genplist_t *dxpl = NULL;        /* DXPL for setting ring */
-    H5AC_ring_t fsm_ring;               /* Free space manager ring */
-    H5AC_ring_t orig_ring = H5AC_RING_INV;      /* Original ring value */
+    H5AC_ring_t orig_ring = H5AC_RING_INV;  /* Original ring value */
+    H5AC_ring_t fsm_ring = H5AC_RING_INV;   /* Ring of fsm */
     hbool_t reset_ring = FALSE;         /* Whether the ring was set */
-    H5FD_mem_t fs_type;                 /* Free space type (mapped from allocation type) */
     herr_t ret_value = SUCCEED;         /* Return value */
 
     FUNC_ENTER_NOAPI_TAG(dxpl_id, H5AC__FREESPACE_TAG, FAIL)
@@ -666,19 +1136,16 @@ HDfprintf(stderr, "%s: Entering - alloc_type = %u, addr = %a, size = %Hu\n", FUN
         HGOTO_DONE(SUCCEED)
     HDassert(addr != 0);        /* Can't deallocate the superblock :-) */
 
-    /* Check for attempting to free space that's a 'temporary' file address */
-    if(H5F_addr_le(f->shared->tmp_addr, addr))
-        HGOTO_ERROR(H5E_RESOURCE, H5E_BADRANGE, FAIL, "attempting to free temporary file space")
+    if(f->shared->first_alloc_dealloc) {
+        HDassert(!H5AC_cache_image_pending(f));
+        if(H5MF_tidy_self_referential_fsm_hack(f, dxpl_id) < 0)
+            HGOTO_ERROR(H5E_RESOURCE, H5E_CANTFREE, FAIL, "tidy of self referential fsm hack failed")
+    } /* end if */
 
-    /* Get free space type from allocation type */
-    fs_type = H5MF_ALLOC_TO_FS_TYPE(f, alloc_type);
-#ifdef H5MF_ALLOC_DEBUG_MORE
-HDfprintf(stderr, "%s: fs_type = %u\n", FUNC, (unsigned)fs_type);
-#endif /* H5MF_ALLOC_DEBUG_MORE */
+    H5MF_alloc_to_fs_type(f, alloc_type, size, &fs_type);
 
     /* Set the ring type in the DXPL */
-    if((fs_type == H5MF_ALLOC_TO_FS_TYPE(f, H5FD_MEM_FSPACE_HDR))
-            || (fs_type == H5MF_ALLOC_TO_FS_TYPE(f, H5FD_MEM_FSPACE_SINFO)))
+    if(H5MF__fsm_type_is_self_referential(f, fs_type))
         fsm_ring = H5AC_RING_MDFSM;
     else
         fsm_ring = H5AC_RING_RDFSM;
@@ -686,6 +1153,19 @@ HDfprintf(stderr, "%s: fs_type = %u\n", FUNC, (unsigned)fs_type);
         HGOTO_ERROR(H5E_RESOURCE, H5E_CANTSET, FAIL, "unable to set ring value")
     reset_ring = TRUE;
 
+    /* we are about to change the contents of the free space manager --
+     * notify metadata cache that the associated fsm ring is
+     * unsettled
+     */
+    /* Only do so for strategies that use free-space managers */
+    if(H5F_HAVE_FREE_SPACE_MANAGER(f))
+        if(H5AC_unsettle_ring(f, fsm_ring) < 0)
+            HGOTO_ERROR(H5E_RESOURCE, H5E_SYSTEM, FAIL, "attempt to notify cache that ring is unsettled failed")
+
+    /* Check for attempting to free space that's a 'temporary' file address */
+    if(H5F_addr_le(f->shared->tmp_addr, addr))
+        HGOTO_ERROR(H5E_RESOURCE, H5E_BADRANGE, FAIL, "attempting to free temporary file space")
+
     /* Set up I/O info for operation */
     fio_info.f = f;
     if(H5FD_MEM_DRAW == alloc_type) {
@@ -712,7 +1192,7 @@ HDfprintf(stderr, "%s: fs_type = %u\n", FUNC, (unsigned)fs_type);
          *  space is at the end of the file
          */
 #ifdef H5MF_ALLOC_DEBUG_MORE
-HDfprintf(stderr, "%s: f->shared->fs_addr[%u] = %a\n", FUNC, (unsigned)fs_type, f->shared->fs_addr[fs_type]);
+HDfprintf(stderr, "%s: fs_addr = %a\n", FUNC, f->shared->fs_addr[fs_type]);
 #endif /* H5MF_ALLOC_DEBUG_MORE */
         if(!H5F_addr_defined(f->shared->fs_addr[fs_type])) {
             htri_t status;          /* "can absorb" status for section into */
@@ -736,8 +1216,8 @@ HDfprintf(stderr, "%s: dropping addr = %a, size = %Hu, on the floor!\n", FUNC, a
 
         /* If we are deleting the free space manager, leave now, to avoid
          *  [re-]starting it.
-	 * or if file space strategy type is not using a free space manager
-	 *   (H5F_FILE_SPACE_AGGR_VFD or H5F_FILE_SPACE_VFD), drop free space
+         * or if file space strategy type is not using a free space manager
+         *  (H5F_FSPACE_STRATEGY_AGGR or H5F_FSPACE_STRATEGY_NONE), drop free space
          *   section on the floor.
          *
          * Note: this drops the space to free on the floor...
@@ -755,38 +1235,42 @@ HDfprintf(stderr, "%s: dropping addr = %a, size = %Hu, on the floor!\n", FUNC, a
          *  space isn't at the end of the file, so start up (or create)
          *  the file space manager
          */
-        if(H5MF__alloc_start(f, dxpl_id, fs_type) < 0)
+        if(H5MF_start_fstype(f, dxpl_id, fs_type) < 0)
             HGOTO_ERROR(H5E_RESOURCE, H5E_CANTINIT, FAIL, "can't initialize file free space")
     } /* end if */
 
-    /* Create free space section for block */
-    if(NULL == (node = H5MF_sect_simple_new(addr, size)))
+    /* Create the free-space section for the freed section */
+    ctype = H5MF_SECT_CLASS_TYPE(f, size);
+    if(NULL == (node = H5MF_sect_new(ctype, addr, size)))
         HGOTO_ERROR(H5E_RESOURCE, H5E_CANTINIT, FAIL, "can't initialize free space section")
 
-    /* Construct user data for callbacks */
-    udata.f = f;
-    udata.dxpl_id = dxpl_id;
-    udata.alloc_type = alloc_type;
-    udata.allow_sect_absorb = TRUE;
-    udata.allow_eoa_shrink_only = FALSE; 
-
-    /* If size of section freed is larger than threshold, add it to the free space manager */
+    /* If size of the freed section is larger than threshold, add it to the free space manager */
     if(size >= f->shared->fs_threshold) {
 	HDassert(f->shared->fs_man[fs_type]);
 
 #ifdef H5MF_ALLOC_DEBUG_MORE
 HDfprintf(stderr, "%s: Before H5FS_sect_add()\n", FUNC);
 #endif /* H5MF_ALLOC_DEBUG_MORE */
+
         /* Add to the free space for the file */
-	if(H5FS_sect_add(f, dxpl_id, f->shared->fs_man[fs_type], (H5FS_section_info_t *)node, H5FS_ADD_RETURNED_SPACE, &udata) < 0)
-	    HGOTO_ERROR(H5E_RESOURCE, H5E_CANTINSERT, FAIL, "can't add section to file free space")
-	node = NULL;
+        if(H5MF_add_sect(f, alloc_type, dxpl_id, f->shared->fs_man[fs_type], node) < 0)
+            HGOTO_ERROR(H5E_RESOURCE, H5E_CANTINSERT, FAIL, "can't add section to file free space")
+        node = NULL;
+
 #ifdef H5MF_ALLOC_DEBUG_MORE
 HDfprintf(stderr, "%s: After H5FS_sect_add()\n", FUNC);
 #endif /* H5MF_ALLOC_DEBUG_MORE */
     } /* end if */
     else {
         htri_t merged;          /* Whether node was merged */
+        H5MF_sect_ud_t udata; 	/* User data for callback */
+
+        /* Construct user data for callbacks */
+        udata.f = f;
+        udata.dxpl_id = dxpl_id;
+        udata.alloc_type = alloc_type;
+        udata.allow_sect_absorb = TRUE;
+        udata.allow_eoa_shrink_only = FALSE;
 
         /* Try to merge the section that is smaller than threshold */
 	if((merged = H5FS_sect_try_merge(f, dxpl_id, f->shared->fs_man[fs_type], (H5FS_section_info_t *)node, H5FS_ADD_RETURNED_SPACE, &udata)) < 0)
@@ -804,7 +1288,7 @@ done:
 
     /* Release section node, if allocated and not added to section list or merged */
     if(node)
-        if(H5MF_sect_simple_free((H5FS_section_info_t *)node) < 0)
+        if(H5MF_sect_free((H5FS_section_info_t *)node) < 0)
             HDONE_ERROR(H5E_RESOURCE, H5E_CANTRELEASE, FAIL, "can't free simple section node")
 
 #ifdef H5MF_ALLOC_DEBUG
@@ -821,6 +1305,14 @@ H5MF_sects_dump(f, dxpl_id, stderr);
  * Function:	H5MF_try_extend
  *
  * Purpose:	Extend a block in the file if possible.
+ *          For non-paged aggregation:
+ *          --try to extend at EOA
+ *          --try to extend into the aggregators
+ *          --try to extend into a free-space section if adjoined
+ *          For paged aggregation:
+ *          --try to extend at EOA
+ *          --try to extend into a free-space section if adjoined
+ *          --try to extend into the page end threshold if a metadata block
  *
  * Return:	Success:	TRUE(1)  - Block was extended
  *                              FALSE(0) - Block could not be extended
@@ -835,14 +1327,16 @@ htri_t
 H5MF_try_extend(H5F_t *f, hid_t dxpl_id, H5FD_mem_t alloc_type, haddr_t addr,
     hsize_t size, hsize_t extra_requested)
 {
-    H5P_genplist_t *dxpl = NULL;        /* DXPL for setting ring */
-    H5AC_ring_t fsm_ring;               /* Free space manager ring */
-    H5AC_ring_t orig_ring = H5AC_RING_INV;      /* Original ring value */
-    haddr_t     end;                    /* End of block to extend */
-    H5FD_mem_t fs_type;			/* Memory type of the free space manager */
-    H5FD_mem_t  map_type;               /* Mapped type */
-    hbool_t reset_ring = FALSE;         /* Whether the ring was set */
-    htri_t	ret_value = FAIL;       /* Return value */
+    H5P_genplist_t *dxpl = NULL;            /* DXPL for setting ring */
+    H5AC_ring_t orig_ring = H5AC_RING_INV;  /* Original ring value */
+    H5AC_ring_t fsm_ring = H5AC_RING_INV;   /* ring of fsm */
+    haddr_t end;                            /* End of block to extend */
+    H5FD_mem_t  map_type;                   /* Mapped type */
+    H5F_mem_page_t fs_type;                 /* free space type */
+    htri_t allow_extend = TRUE;		    /* Possible to extend the block */
+    hsize_t frag_size = 0;                  /* Size of mis-aligned fragment */
+    hbool_t reset_ring = FALSE;             /* Whether the ring was set */
+    htri_t ret_value = FALSE;      	    /* Return value */
 
     FUNC_ENTER_NOAPI_TAG(dxpl_id, H5AC__FREESPACE_TAG, FAIL)
 #ifdef H5MF_ALLOC_DEBUG
@@ -859,12 +1353,33 @@ HDfprintf(stderr, "%s: Entering: alloc_type = %u, addr = %a, size = %Hu, extra_r
     /* Compute end of block to extend */
     end = addr + size;
 
+    /* For paged aggregation:
+     *   To extend a small block: can only extend if not crossing page boundary 
+     *   To extend a large block at EOA: calculate in advance mis-aligned fragment so EOA will still end at page boundary
+     */
+    if(H5F_PAGED_AGGR(f)) {
+        if(size < f->shared->fs_page_size) {
+            /* To extend a small block: cannot cross page boundary */
+            if((addr / f->shared->fs_page_size) != (((end + extra_requested) - 1) / f->shared->fs_page_size))
+                allow_extend = FALSE;
+        } /* end if */
+        else {
+            haddr_t eoa;  /* EOA for the file */
+
+            /*   To extend a large block: calculate in advance the mis-aligned fragment so EOA will end at page boundary if extended */
+            if(HADDR_UNDEF == (eoa = H5F_get_eoa(f, alloc_type)))
+                HGOTO_ERROR(H5E_RESOURCE, H5E_CANTGET, FAIL, "Unable to get eoa")
+            HDassert(!(eoa % f->shared->fs_page_size));
+
+            H5MF_EOA_MISALIGN(f, (eoa+extra_requested), f->shared->fs_page_size, frag_size);
+        } /* end else */
+    } /* end if */
+
     /* Get free space type from allocation type */
-    fs_type = H5MF_ALLOC_TO_FS_TYPE(f, alloc_type);
+    H5MF_alloc_to_fs_type(f, alloc_type, size, &fs_type);
 
     /* Set the ring type in the DXPL */
-    if((fs_type == H5MF_ALLOC_TO_FS_TYPE(f, H5FD_MEM_FSPACE_HDR))
-            || (fs_type == H5MF_ALLOC_TO_FS_TYPE(f, H5FD_MEM_FSPACE_SINFO)))
+    if(H5MF__fsm_type_is_self_referential(f, fs_type))
         fsm_ring = H5AC_RING_MDFSM;
     else
         fsm_ring = H5AC_RING_RDFSM;
@@ -872,29 +1387,90 @@ HDfprintf(stderr, "%s: Entering: alloc_type = %u, addr = %a, size = %Hu, extra_r
         HGOTO_ERROR(H5E_RESOURCE, H5E_CANTSET, FAIL, "unable to set ring value")
     reset_ring = TRUE;
 
-    /* Check if the block is exactly at the end of the file */
-    if((ret_value = H5FD_try_extend(f->shared->lf, map_type, f, dxpl_id, end, extra_requested)) < 0)
-        HGOTO_ERROR(H5E_RESOURCE, H5E_CANTEXTEND, FAIL, "error extending file")
-    else if(ret_value == FALSE) {
-        H5F_blk_aggr_t *aggr;   /* Aggregator to use */
+    if(allow_extend) {
+        /* Try extending the block at EOA */
+        if((ret_value = H5F_try_extend(f, dxpl_id, map_type, end, extra_requested + frag_size)) < 0)
+            HGOTO_ERROR(H5E_RESOURCE, H5E_CANTEXTEND, FAIL, "error extending file")
+#ifdef H5MF_ALLOC_DEBUG_MORE
+HDfprintf(stderr, "%s: extended = %t\n", FUNC, ret_value);
+#endif /* H5MF_ALLOC_DEBUG_MORE */
+
+        /* If extending at EOA succeeds: */
+        /*   for paged aggregation, put the fragment into the large-sized free-space manager */
+        if(ret_value == TRUE && H5F_PAGED_AGGR(f) && frag_size) {
+            H5MF_free_section_t *node = NULL;   /* Free space section pointer */
+
+            /* Should be large-sized block */
+            HDassert(size >= f->shared->fs_page_size);
+
+            /* Start up the free-space manager */
+            if(!(f->shared->fs_man[fs_type]))
+                if(H5MF_start_fstype(f, dxpl_id, fs_type) < 0)
+                    HGOTO_ERROR(H5E_RESOURCE, H5E_CANTINIT, FAIL, "can't initialize file free space")
+
+            /* Create free space section for the fragment */
+            if(NULL == (node = H5MF_sect_new(H5MF_FSPACE_SECT_LARGE, end + extra_requested, frag_size)))
+                HGOTO_ERROR(H5E_RESOURCE, H5E_CANTINIT, FAIL, "can't initialize free space section")
+
+            /* Add the fragment to the large-sized free-space manager */
+            if(H5MF_add_sect(f, alloc_type, dxpl_id, f->shared->fs_man[fs_type], node) < 0)
+                HGOTO_ERROR(H5E_RESOURCE, H5E_CANTINSERT, FAIL, "can't re-add section to file free space")
+
+            node = NULL;
+        } /* end if */
 
-        /* Check for test block able to extend aggregation block */
-        aggr = (map_type == H5FD_MEM_DRAW) ?  &(f->shared->sdata_aggr) : &(f->shared->meta_aggr);
-        if((ret_value = H5MF_aggr_try_extend(f, dxpl_id, aggr, map_type, end, extra_requested)) < 0)
-            HGOTO_ERROR(H5E_RESOURCE, H5E_CANTEXTEND, FAIL, "error extending aggregation block")
-        else if(ret_value == FALSE) {
+        /* For non-paged aggregation: try to extend into the aggregators */
+        if(ret_value == FALSE && (f->shared->fs_strategy == H5F_FSPACE_STRATEGY_FSM_AGGR ||
+                                  f->shared->fs_strategy == H5F_FSPACE_STRATEGY_AGGR) ) {
+            H5F_blk_aggr_t *aggr;   /* Aggregator to use */
+
+            /* Check if the block is able to extend into aggregation block */
+            aggr = (map_type == H5FD_MEM_DRAW) ?  &(f->shared->sdata_aggr) : &(f->shared->meta_aggr);
+            if((ret_value = H5MF_aggr_try_extend(f, dxpl_id, aggr, map_type, end, extra_requested)) < 0)
+                HGOTO_ERROR(H5E_RESOURCE, H5E_CANTEXTEND, FAIL, "error extending aggregation block")
+
+#ifdef H5MF_ALLOC_DEBUG_MORE
+HDfprintf(stderr, "%s: H5MF_aggr_try_extend = %t\n", FUNC, ret_value);
+#endif /* H5MF_ALLOC_DEBUG_MORE */
+        } /* end if */
+
+        /* If no extension so far, try to extend into a free-space section */
+        if(ret_value == FALSE && ((f->shared->fs_strategy == H5F_FSPACE_STRATEGY_FSM_AGGR) ||
+                                  (H5F_PAGED_AGGR(f))) ) {
+            H5MF_sect_ud_t udata;       /* User data */
+
+            /* Construct user data for callbacks */
+            udata.f = f;
+            udata.dxpl_id = dxpl_id;
+            udata.alloc_type = alloc_type;
 
             /* Check if the free space for the file has been initialized */
             if(!f->shared->fs_man[fs_type] && H5F_addr_defined(f->shared->fs_addr[fs_type]))
-                if(H5MF__alloc_open(f, dxpl_id, fs_type) < 0)
+                /* Open the free-space manager */
+                if(H5MF_open_fstype(f, dxpl_id, fs_type) < 0)
                     HGOTO_ERROR(H5E_RESOURCE, H5E_CANTINIT, FAIL, "can't initialize file free space")
 
-            /* Check for test block able to block in free space manager */
-            if(f->shared->fs_man[fs_type])
-                if((ret_value = H5FS_sect_try_extend(f, dxpl_id, f->shared->fs_man[fs_type], addr, size, extra_requested)) < 0)
+            /* Try to extend the block into a free-space section */
+            if(f->shared->fs_man[fs_type]) {
+                if((ret_value = H5FS_sect_try_extend(f, dxpl_id, f->shared->fs_man[fs_type], addr, size, extra_requested, H5FS_ADD_RETURNED_SPACE, &udata)) < 0)
                     HGOTO_ERROR(H5E_RESOURCE, H5E_CANTEXTEND, FAIL, "error extending block in free space manager")
+#ifdef H5MF_ALLOC_DEBUG_MORE
+HDfprintf(stderr, "%s: Try to H5FS_sect_try_extend = %t\n", FUNC, ret_value);
+#endif /* H5MF_ALLOC_DEBUG_MORE */
+            } /* end if */
+
+            /* For paged aggregation and a metadata block: try to extend into page end threshold */
+            if(ret_value == FALSE && H5F_PAGED_AGGR(f) && map_type != H5FD_MEM_DRAW) {
+                H5MF_EOA_MISALIGN(f, end, f->shared->fs_page_size, frag_size);
+
+                if(frag_size <= H5F_PGEND_META_THRES(f) && extra_requested <= frag_size)
+                    ret_value = TRUE;
+#ifdef H5MF_ALLOC_DEBUG_MORE
+HDfprintf(stderr, "%s: Try to extend into the page end threshold = %t\n", FUNC, ret_value);
+#endif /* H5MF_ALLOC_DEBUG_MORE */
+            } /* end if */
         } /* end if */
-    } /* end else-if */
+    } /* allow_extend */
 
 done:
     /* Reset the ring in the DXPL */
@@ -914,174 +1490,316 @@ H5MF_sects_dump(f, dxpl_id, stderr);
 
 
 /*-------------------------------------------------------------------------
- * Function:    H5MF_get_freespace
+ * Function:    H5MF_try_shrink
  *
- * Purpose:     Retrieve the amount of free space in a file.
+ * Purpose:     Try to shrink the size of a file with a block or absorb it
+ *              into a block aggregator.
  *
- * Return:      Success:        Amount of free space in file
- *              Failure:        Negative
+ * Return:      Non-negative on success/Negative on failure
  *
  * Programmer:  Quincey Koziol
- *              Monday, October  6, 2003
+ *              koziol@hdfgroup.org
+ *              Feb 14 2008
  *
- * Modifications:
- *      Vailin Choi; July 2012
- *      As the default free-list mapping is changed to H5FD_FLMAP_DICHOTOMY,
- *      checks are added to account for the last section of each free-space manager
- *      and the remaining space in the two aggregators are at EOF.
  *-------------------------------------------------------------------------
  */
-herr_t
-H5MF_get_freespace(H5F_t *f, hid_t dxpl_id, hsize_t *tot_space, hsize_t *meta_size)
+htri_t
+H5MF_try_shrink(H5F_t *f, H5FD_mem_t alloc_type, hid_t dxpl_id, haddr_t addr,
+    hsize_t size)
 {
-    H5P_genplist_t *dxpl = NULL; /* DXPL for setting ring */
-    H5AC_ring_t curr_ring;      /* Current ring value */
-    H5AC_ring_t needed_ring;    /* Ring value needed for loop iteration  */
-    H5AC_ring_t orig_ring = H5AC_RING_INV;      /* Original ring value */
-    haddr_t eoa;                /* End of allocated space in the file */
-    haddr_t ma_addr = HADDR_UNDEF;    /* Base "metadata aggregator" address */
-    hsize_t ma_size = 0;        /* Size of "metadata aggregator" */
-    haddr_t sda_addr = HADDR_UNDEF;    /* Base "small data aggregator" address */
-    hsize_t sda_size = 0;       /* Size of "small data aggregator" */
-    hsize_t tot_fs_size = 0;    /* Amount of all free space managed */
-    hsize_t tot_meta_size = 0;  /* Amount of metadata for free space managers */
-    H5FD_mem_t type;            /* Memory type for iteration */
-    hbool_t fs_started[H5FD_MEM_NTYPES]; /* Indicate whether the free-space manager has been started */
-    hbool_t eoa_shrank;		/* Whether an EOA shrink occurs */
-    hbool_t reset_ring = FALSE; /* Whether the ring was set */
-    herr_t ret_value = SUCCEED; /* Return value */
+    H5MF_free_section_t *node = NULL;   /* Free space section pointer */
+    H5MF_sect_ud_t udata;               /* User data for callback */
+    H5FS_section_class_t *sect_cls;	/* Section class */
+    H5P_genplist_t *dxpl = NULL;        /* DXPL for setting ring */
+    H5AC_ring_t orig_ring = H5AC_RING_INV;  /* Original ring value */
+    H5AC_ring_t fsm_ring = H5AC_RING_INV;   /* Ring of fsm */
+    H5F_mem_page_t fs_type;                 /* Free space type */
+    hbool_t reset_ring = FALSE;             /* Whether the ring was set */
+    htri_t ret_value = FAIL;                /* Return value */
 
     FUNC_ENTER_NOAPI_TAG(dxpl_id, H5AC__FREESPACE_TAG, FAIL)
+#ifdef H5MF_ALLOC_DEBUG
+HDfprintf(stderr, "%s: Entering - alloc_type = %u, addr = %a, size = %Hu\n", FUNC, (unsigned)alloc_type, addr, size);
+#endif /* H5MF_ALLOC_DEBUG */
 
-    /* check args */
+    /* check arguments */
     HDassert(f);
     HDassert(f->shared);
     HDassert(f->shared->lf);
+    HDassert(H5F_addr_defined(addr));
+    HDassert(size > 0);
 
-    /* Retrieve the 'eoa' for the file */
-    if(HADDR_UNDEF == (eoa = H5F_get_eoa(f, H5FD_MEM_DEFAULT)))
-	HGOTO_ERROR(H5E_RESOURCE, H5E_CANTGET, FAIL, "driver get_eoa request failed")
+    /* Set up free-space section class information */
+    sect_cls = H5MF_SECT_CLS_TYPE(f, size);
+    HDassert(sect_cls);
+
+    /* Get free space type from allocation type */
+    H5MF_alloc_to_fs_type(f, alloc_type, size, &fs_type);
 
     /* Set the ring type in the DXPL */
-    if(H5AC_set_ring(dxpl_id, H5AC_RING_RDFSM, &dxpl, &orig_ring) < 0)
+    if(H5MF__fsm_type_is_self_referential(f, fs_type))
+        fsm_ring = H5AC_RING_MDFSM;
+    else
+        fsm_ring = H5AC_RING_RDFSM;
+    if(H5AC_set_ring(dxpl_id, fsm_ring, &dxpl, &orig_ring) < 0)
         HGOTO_ERROR(H5E_RESOURCE, H5E_CANTSET, FAIL, "unable to set ring value")
     reset_ring = TRUE;
-    curr_ring = H5AC_RING_RDFSM;
 
-    /* Retrieve metadata aggregator info, if available */
-    if(H5MF_aggr_query(f, &(f->shared->meta_aggr), &ma_addr, &ma_size) < 0)
-        HGOTO_ERROR(H5E_RESOURCE, H5E_CANTGET, FAIL, "can't query metadata aggregator stats")
+    /* Create free-space section for block */
+    if(NULL == (node = H5MF_sect_new(sect_cls->type, addr, size)))
+        HGOTO_ERROR(H5E_RESOURCE, H5E_CANTINIT, FAIL, "can't initialize free space section")
 
-    /* Retrieve 'small data' aggregator info, if available */
-    if(H5MF_aggr_query(f, &(f->shared->sdata_aggr), &sda_addr, &sda_size) < 0)
-        HGOTO_ERROR(H5E_RESOURCE, H5E_CANTGET, FAIL, "can't query small data aggregator stats")
+    /* Construct user data for callbacks */
+    udata.f = f;
+    udata.dxpl_id = dxpl_id;
+    udata.alloc_type = alloc_type;
+    udata.allow_sect_absorb = FALSE;    /* Force section to be absorbed into aggregator */
+    udata.allow_eoa_shrink_only = FALSE;
 
-    /* Iterate over all the free space types that have managers and get each free list's space */
-    for(type = H5FD_MEM_DEFAULT; type < H5FD_MEM_NTYPES; H5_INC_ENUM(H5FD_mem_t, type)) {
+    /* Check if the block can shrink the container */
+    if(sect_cls->can_shrink) {
+        if((ret_value = (*sect_cls->can_shrink)((const H5FS_section_info_t *)node, &udata)) < 0)
+            HGOTO_ERROR(H5E_RESOURCE, H5E_CANTMERGE, FAIL, "can't check if section can shrink container")
+        if(ret_value > 0) {
+            HDassert(sect_cls->shrink);
 
-	fs_started[type] = FALSE;
+            if((*sect_cls->shrink)((H5FS_section_info_t **)&node, &udata) < 0)
+                HGOTO_ERROR(H5E_RESOURCE, H5E_CANTSHRINK, FAIL, "can't shrink container")
+        } /* end if */
+    } /* end if */
 
-        /* test to see if we need to switch rings -- do so if required */
-        if((type == H5MF_ALLOC_TO_FS_TYPE(f, H5FD_MEM_FSPACE_HDR))
-                || (type == H5MF_ALLOC_TO_FS_TYPE(f, H5FD_MEM_FSPACE_SINFO)))
-            needed_ring = H5AC_RING_MDFSM;
-        else
-            needed_ring = H5AC_RING_RDFSM;
+done:
+    /* Reset the ring in the DXPL */
+    if(reset_ring)
+        if(H5AC_reset_ring(dxpl, orig_ring) < 0)
+            HDONE_ERROR(H5E_RESOURCE, H5E_CANTSET, FAIL, "unable to set property value")
 
-        if(needed_ring != curr_ring) {
-            if(H5AC_set_ring(dxpl_id, needed_ring, &dxpl, &curr_ring) < 0)
-                HGOTO_ERROR(H5E_RESOURCE, H5E_CANTSET, FAIL, "unable to set ring value (2)")
-            curr_ring = needed_ring;
-        } /* end if */
+    /* Free section node allocated */
+    if(node && H5MF_sect_free((H5FS_section_info_t *)node) < 0)
+        HDONE_ERROR(H5E_RESOURCE, H5E_CANTRELEASE, FAIL, "can't free simple section node")
 
-	/* Check if the free space for the file has been initialized */
-        if(!f->shared->fs_man[type] && H5F_addr_defined(f->shared->fs_addr[type])) {
-            if(H5MF__alloc_open(f, dxpl_id, type) < 0)
-                HGOTO_ERROR(H5E_RESOURCE, H5E_CANTINIT, FAIL, "can't initialize file free space")
-            HDassert(f->shared->fs_man[type]);
-            fs_started[type] = TRUE;
-        } /* end if */
+#ifdef H5MF_ALLOC_DEBUG
+HDfprintf(stderr, "%s: Leaving, ret_value = %d\n", FUNC, ret_value);
+#endif /* H5MF_ALLOC_DEBUG */
+    FUNC_LEAVE_NOAPI_TAG(ret_value, FAIL)
+} /* end H5MF_try_shrink() */
 
-	/* Check if there's free space of this type */
-        if(f->shared->fs_man[type]) {
-            hsize_t type_fs_size = 0;    /* Amount of free space managed for each type */
-            hsize_t type_meta_size = 0;  /* Amount of free space metadata for each type */
+
+/*-------------------------------------------------------------------------
+ * Function:    H5MF_close
+ *
+ * Purpose:     Close the free space tracker(s) for a file:
+ *              paged or non-paged aggregation
+ *
+ * Return:	SUCCEED/FAIL
+ *
+ * Programmer:  Vailin Choi; Dec 2012
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5MF_close(H5F_t *f, hid_t dxpl_id)
+{
+    herr_t ret_value = SUCCEED;         /* Return value */
 
-            /* Retrieve free space size from free space manager */
-            if(H5FS_sect_stats(f->shared->fs_man[type], &type_fs_size, NULL) < 0)
-                HGOTO_ERROR(H5E_RESOURCE, H5E_CANTGET, FAIL, "can't query free space stats")
-            if(H5FS_size(f, f->shared->fs_man[type], &type_meta_size) < 0)
-                HGOTO_ERROR(H5E_RESOURCE, H5E_CANTGET, FAIL, "can't query free space metadata stats")
+    FUNC_ENTER_NOAPI_TAG(dxpl_id, H5AC__FREESPACE_TAG, FAIL)
+#ifdef H5MF_ALLOC_DEBUG
+HDfprintf(stderr, "%s: Entering\n", FUNC);
+#endif /* H5MF_ALLOC_DEBUG */
 
-            /* Increment total free space for types */
-            tot_fs_size += type_fs_size;
-            tot_meta_size += type_meta_size;
-	} /* end if */
-    } /* end for */
+    /* check args */
+    HDassert(f);
+    HDassert(f->shared);
 
-    /* Iterate until no more EOA shrink occurs */
-    do {
-	eoa_shrank = FALSE;
+    if(H5F_PAGED_AGGR(f)) {
+        if((ret_value = H5MF__close_pagefs(f, dxpl_id)) < 0)
+            HGOTO_ERROR(H5E_FILE, H5E_CANTFREE, FAIL, "can't close free-space managers for 'page' file space")
+    } /* end if */
+    else {
+        if((ret_value = H5MF__close_aggrfs(f, dxpl_id)) < 0)
+            HGOTO_ERROR(H5E_FILE, H5E_CANTFREE, FAIL, "can't close free-space managers for 'aggr' file space")
+    } /* end else */
 
-	/* Check the last section of each free-space manager */
-	for(type = H5FD_MEM_DEFAULT; type < H5FD_MEM_NTYPES; H5_INC_ENUM(H5FD_mem_t, type)) {
-	    haddr_t sect_addr = HADDR_UNDEF;
-	    hsize_t sect_size = 0;
-
-	    if(f->shared->fs_man[type]) {
-		if(H5FS_sect_query_last_sect(f->shared->fs_man[type], &sect_addr, &sect_size) < 0)
-		    HGOTO_ERROR(H5E_RESOURCE, H5E_CANTGET, FAIL, "can't query last section on merge list")
-
-		/* Deduct space from previous accumulation if the section is at EOA */
-		if(H5F_addr_eq(sect_addr + sect_size, eoa)) {
-		    eoa = sect_addr;
-		    eoa_shrank = TRUE;
-		    tot_fs_size -= sect_size;
-		} /* end if */
-	    } /* end if */
-	} /* end for */
-
-	/* Check the metadata and raw data aggregators */
-	if(ma_size > 0 && H5F_addr_eq(ma_addr + ma_size, eoa)) {
-	    eoa = ma_addr;
-	    eoa_shrank = TRUE;
-	    ma_size = 0;
-	} /* end if */
-	if(sda_size > 0 && H5F_addr_eq(sda_addr + sda_size, eoa)) {
-	    eoa = sda_addr;
-	    eoa_shrank = TRUE;
-	    sda_size = 0;
-	} /* end if */
-    } while(eoa_shrank);
+done:
 
-    /* Close the free-space managers if they were opened earlier in this routine */
-    for(type = H5FD_MEM_DEFAULT; type < H5FD_MEM_NTYPES; H5_INC_ENUM(H5FD_mem_t, type)) {
-        if(fs_started[type]) {
+#ifdef H5MF_ALLOC_DEBUG
+HDfprintf(stderr, "%s: Leaving\n", FUNC);
+#endif /* H5MF_ALLOC_DEBUG */
+    FUNC_LEAVE_NOAPI_TAG(ret_value, FAIL)
+} /* end H5MF_close() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:    H5MF__close_delete_fstype
+ *
+ * Purpose:     Common code for closing and deleting the freespace manager
+ *              of TYPE for file.
+ *              Note that TYPE can be H5F_mem_page_t or H5FD_mem_t enum types.
+ *
+ * Return:	SUCCEED/FAIL
+ *
+ * Programmer:	Vailin Choi
+ *              Jan 2016
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+H5MF__close_delete_fstype(H5F_t *f, hid_t dxpl_id, H5F_mem_page_t type)
+{
+    herr_t ret_value = SUCCEED;         /* Return value */
+
+    FUNC_ENTER_STATIC_TAG(dxpl_id, H5AC__FREESPACE_TAG, FAIL)
+#ifdef H5MF_ALLOC_DEBUG
+HDfprintf(stderr, "%s: Entering\n", FUNC);
+#endif /* H5MF_ALLOC_DEBUG */
+
+    /* check args */
+    HDassert(f);
+    HDassert(f->shared);
+    if(H5F_PAGED_AGGR(f))
+        HDassert(type < H5F_MEM_PAGE_NTYPES);
+    else
+        HDassert((H5FD_mem_t)type < H5FD_MEM_NTYPES);
+
+#ifdef H5MF_ALLOC_DEBUG_MORE
+HDfprintf(stderr, "%s: Check 1.0 - f->shared->fs_man[%u] = %p, f->shared->fs_addr[%u] = %a\n", FUNC, (unsigned)type, f->shared->fs_man[type], (unsigned)type, f->shared->fs_addr[type]);
+#endif /* H5MF_ALLOC_DEBUG_MORE */
+
+    /* If the free space manager for this type is open, close it */
+    if(f->shared->fs_man[type])
+        if(H5MF__close_fstype(f, dxpl_id, type) < 0)
+            HGOTO_ERROR(H5E_RESOURCE, H5E_CANTRELEASE, FAIL, "can't close the free space manager")
+
+#ifdef H5MF_ALLOC_DEBUG_MORE
+HDfprintf(stderr, "%s: Check 2.0 - f->shared->fs_man[%u] = %p, f->shared->fs_addr[%u] = %a\n", FUNC, (unsigned)type, f->shared->fs_man[type], (unsigned)type, f->shared->fs_addr[type]);
+#endif /* H5MF_ALLOC_DEBUG_MORE */
+
+    /* If there is free space manager info for this type, delete it */
+    if(H5F_addr_defined(f->shared->fs_addr[type]))
+        if(H5MF__delete_fstype(f, dxpl_id, type) < 0)
+            HGOTO_ERROR(H5E_RESOURCE, H5E_CANTRELEASE, FAIL, "can't delete the free space manager")
+
+done:
+#ifdef H5MF_ALLOC_DEBUG
+HDfprintf(stderr, "%s: Leaving\n", FUNC);
+#endif /* H5MF_ALLOC_DEBUG */
+    FUNC_LEAVE_NOAPI_TAG(ret_value, FAIL)
+} /* H5MF__close_delete() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:    H5MF_try_close
+ *
+ * Purpose:     This is called by H5Fformat_convert() to close and delete
+ *              free-space managers when downgrading persistent free-space
+ *              to non-persistent.
+ *
+ * Return:	SUCCEED/FAIL
+ *
+ * Programmer:	Vailin Choi
+ *              Jan 2016
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5MF_try_close(H5F_t *f, hid_t dxpl_id)
+{
+    H5P_genplist_t *dxpl = NULL;        /* DXPL for setting ring */
+    H5AC_ring_t curr_ring = H5AC_RING_INV;      /* Current ring value */
+    H5AC_ring_t needed_ring = H5AC_RING_INV;    /* Ring value needed for this iteration  */
+    H5AC_ring_t orig_ring = H5AC_RING_INV;      /* Original ring value */
+    hbool_t reset_ring = FALSE;         /* Whether the ring was set */
+    herr_t ret_value = SUCCEED;         /* Return value */
+
+    FUNC_ENTER_NOAPI_TAG(dxpl_id, H5AC__FREESPACE_TAG, FAIL)
+#ifdef H5MF_ALLOC_DEBUG
+HDfprintf(stderr, "%s: Entering\n", FUNC);
+#endif /* H5MF_ALLOC_DEBUG */
+
+    /* check args */
+    HDassert(f);
 
+    /* If there have been no file space allocations / deallocation so 
+     * far, must call H5MF_tidy_self_referential_fsm_hack() to float 
+     * all self referential FSMs and release file space allocated to
+     * them.  Otherwise, the function will be called after the format
+     * conversion, and will become very confused.
+     *
+     * The situation is further complicated if a cache image exists
+     * and had not yet been loaded into the metadata cache.  In this
+     * case, call H5AC_force_cache_image_load() instead of 
+     * H5MF_tidy_self_referential_fsm_hack().  H5AC_force_cache_image_load()
+     * will load the cache image, and then call 
+     * H5MF_tidy_self_referential_fsm_hack() to discard the cache image 
+     * block.
+     */
+    if(f->shared->first_alloc_dealloc) {
+        if(H5AC_cache_image_pending(f)) {
+            if(H5AC_force_cache_image_load(f, dxpl_id) < 0)
+                HGOTO_ERROR(H5E_RESOURCE, H5E_CANTFREE, FAIL, "forced cache image load failed")
+        } /* end if */
+        else {
+            if(H5MF_tidy_self_referential_fsm_hack(f, dxpl_id) < 0)
+                HGOTO_ERROR(H5E_RESOURCE, H5E_CANTFREE, FAIL, "tidy of self referential fsm hack failed")
+        } /* end else */
+    } /* end if */
+
+    /* Set the ring type in the DXPL.  In most cases, we will
+     * need H5AC_RING_RDFSM, so initialy set the ring in
+     * the DXPL to that value.  We will alter this later if
+     * needed.
+     */
+    if(H5AC_set_ring(dxpl_id, H5AC_RING_RDFSM, &dxpl, &orig_ring) < 0)
+        HGOTO_ERROR(H5E_RESOURCE, H5E_CANTSET, FAIL, "unable to set ring value")
+    reset_ring = TRUE;
+    curr_ring = H5AC_RING_RDFSM;
+
+    if(H5F_PAGED_AGGR(f)) {
+        H5F_mem_page_t ptype; 	/* Memory type for iteration */
+
+        /* Iterate over all the free space types that have managers and 
+         * get each free list's space 
+         */
+        for(ptype = H5F_MEM_PAGE_META; ptype < H5F_MEM_PAGE_NTYPES; H5_INC_ENUM(H5F_mem_page_t, ptype)) {
+            /* Test to see if we need to switch rings -- do so if required */
+            if(H5MF__fsm_type_is_self_referential(f, ptype))
+                needed_ring = H5AC_RING_MDFSM;
+            else
+                needed_ring = H5AC_RING_RDFSM;
+
+            if(needed_ring != curr_ring ) {
+                if(H5AC_set_ring(dxpl_id, needed_ring, &dxpl, &curr_ring) < 0)
+                    HGOTO_ERROR(H5E_RESOURCE, H5E_CANTSET, FAIL, "unable to set ring value (1)")
+                curr_ring = needed_ring;
+            } /* end if */
+
+            if(H5MF__close_delete_fstype(f, dxpl_id, ptype) < 0)
+                HGOTO_ERROR(H5E_RESOURCE, H5E_CANTRELEASE, FAIL, "can't close the free space manager")
+        } /* end for */
+    } /* end if */
+    else {
+        H5FD_mem_t type;          	/* Memory type for iteration */
+
+        /* Iterate over all the free space types that have managers and 
+         * get each free list's space 
+         */
+        for(type = H5FD_MEM_DEFAULT; type < H5FD_MEM_NTYPES; H5_INC_ENUM(H5FD_mem_t, type)) {
             /* test to see if we need to switch rings -- do so if required */
-            if((type == H5MF_ALLOC_TO_FS_TYPE(f, H5FD_MEM_FSPACE_HDR))
-                    || (type == H5MF_ALLOC_TO_FS_TYPE(f, H5FD_MEM_FSPACE_SINFO)))
+            if(H5MF__fsm_type_is_self_referential(f, (H5F_mem_page_t)type))
                 needed_ring = H5AC_RING_MDFSM;
             else
                 needed_ring = H5AC_RING_RDFSM;
 
             if(needed_ring != curr_ring) {
                 if(H5AC_set_ring(dxpl_id, needed_ring, &dxpl, &curr_ring) < 0)
-                    HGOTO_ERROR(H5E_RESOURCE, H5E_CANTSET, FAIL, "unable to set ring value (3)")
+                    HGOTO_ERROR(H5E_RESOURCE, H5E_CANTSET, FAIL, "unable to set ring value")
                 curr_ring = needed_ring;
             } /* end if */
 
-            if(H5MF__alloc_close(f, dxpl_id, type) < 0)
-                HGOTO_ERROR(H5E_RESOURCE, H5E_CANTINIT, FAIL, "can't close file free space")
-        } /* end if */
-    } /* end for */
-
-    /* Set the value(s) to return */
-    /* (The metadata & small data aggregators count as free space now, since they aren't at EOA) */
-    if(tot_space)
-	*tot_space = tot_fs_size + ma_size + sda_size;
-    if(meta_size)
-	*meta_size = tot_meta_size;
+            if(H5MF__close_delete_fstype(f, dxpl_id, (H5F_mem_page_t)type) < 0)
+                HGOTO_ERROR(H5E_RESOURCE, H5E_CANTRELEASE, FAIL, "can't close the free space manager")
+        } /* end for */
+    } /* end else */
 
 done:
     /* Reset the ring in the DXPL */
@@ -1089,75 +1807,370 @@ done:
         if(H5AC_reset_ring(dxpl, orig_ring) < 0)
             HDONE_ERROR(H5E_RESOURCE, H5E_CANTSET, FAIL, "unable to set property value")
 
+#ifdef H5MF_ALLOC_DEBUG
+HDfprintf(stderr, "%s: Leaving\n", FUNC);
+#endif /* H5MF_ALLOC_DEBUG */
     FUNC_LEAVE_NOAPI_TAG(ret_value, FAIL)
-} /* end H5MF_get_freespace() */
+} /* H5MF_try_close() */
 
 
 /*-------------------------------------------------------------------------
- * Function:    H5MF_try_shrink
+ * Function:    H5MF__close_aggrfs
  *
- * Purpose:     Try to shrink the size of a file with a block or absorb it
- *              into a block aggregator.
+ * Purpose:     Close the free space tracker(s) for a file: non-paged aggregation
  *
- * Return:      Non-negative on success/Negative on failure
+ * Return:      SUCCEED/FAIL
  *
  * Programmer:  Quincey Koziol
- *              koziol@hdfgroup.org
- *              Feb 14 2008
+ *              Tuesday, January 22, 2008
  *
  *-------------------------------------------------------------------------
  */
-htri_t
-H5MF_try_shrink(H5F_t *f, H5FD_mem_t alloc_type, hid_t dxpl_id, haddr_t addr,
-    hsize_t size)
+static herr_t
+H5MF__close_aggrfs(H5F_t *f, hid_t dxpl_id)
 {
-    H5MF_free_section_t *node = NULL;   /* Free space section pointer */
-    H5MF_sect_ud_t udata;               /* User data for callback */
-    htri_t ret_value = FAIL;                   /* Return value */
+    H5P_genplist_t *dxpl = NULL;        /* DXPL for setting ring */
+    H5AC_ring_t curr_ring = H5AC_RING_INV;      /* Current ring value */
+    H5AC_ring_t needed_ring = H5AC_RING_INV;    /* Ring value needed for this iteration.  */
+    H5AC_ring_t orig_ring = H5AC_RING_INV;      /* Original ring value */
+    H5FD_mem_t type;          	        /* Memory type for iteration */
+    hbool_t reset_ring = FALSE;         /* Whether the ring was set */
+    herr_t ret_value = SUCCEED;	        /* Return value */
 
-    FUNC_ENTER_NOAPI(FAIL)
+    FUNC_ENTER_STATIC_TAG(dxpl_id, H5AC__FREESPACE_TAG, FAIL)
 #ifdef H5MF_ALLOC_DEBUG
-HDfprintf(stderr, "%s: Entering - alloc_type = %u, addr = %a, size = %Hu\n", FUNC, (unsigned)alloc_type, addr, size);
+HDfprintf(stderr, "%s: Entering\n", FUNC);
 #endif /* H5MF_ALLOC_DEBUG */
 
-    /* check arguments */
+    /* check args */
     HDassert(f);
     HDassert(f->shared);
     HDassert(f->shared->lf);
-    HDassert(H5F_addr_defined(addr));
-    HDassert(size > 0);
+    HDassert(f->shared->sblock);
 
-    /* Create free space section for block */
-    if(NULL == (node = H5MF_sect_simple_new(addr, size)))
-        HGOTO_ERROR(H5E_RESOURCE, H5E_CANTINIT, FAIL, "can't initialize free space section")
+    /* Set the ring type in the DXPL.  In most cases, we will
+     * need H5AC_RING_RDFSM, so initialy set the ring in
+     * the DXPL to that value.  We will alter this later if
+     * needed.
+     */
+    if(H5AC_set_ring(dxpl_id, H5AC_RING_RDFSM, &dxpl, &orig_ring) < 0)
+        HGOTO_ERROR(H5E_RESOURCE, H5E_CANTSET, FAIL, "unable to set ring value")
+    reset_ring = TRUE;
+    curr_ring = H5AC_RING_RDFSM;
 
-    /* Construct user data for callbacks */
-    udata.f = f;
-    udata.dxpl_id = dxpl_id;
-    udata.alloc_type = alloc_type;
-    udata.allow_sect_absorb = FALSE;    /* Force section to be absorbed into aggregator */
-    udata.allow_eoa_shrink_only = FALSE; 
-
-    /* Call the "can shrink" callback for the section */
-    if((ret_value = H5MF_sect_simple_can_shrink((const H5FS_section_info_t *)node, &udata)) < 0)
-        HGOTO_ERROR(H5E_RESOURCE, H5E_CANTMERGE, FAIL, "can't check if section can shrink container")
-    else if(ret_value > 0) {
-        /* Shrink or absorb the section */
-        if(H5MF_sect_simple_shrink((H5FS_section_info_t **)&node, &udata) < 0)
-            HGOTO_ERROR(H5E_RESOURCE, H5E_CANTSHRINK, FAIL, "can't shrink container")
+    /* Free the space in aggregators */
+    /* (for space not at EOA, it may be put into free space managers) */
+    if(H5MF_free_aggrs(f, dxpl_id) < 0)
+        HGOTO_ERROR(H5E_FILE, H5E_CANTFREE, FAIL, "can't free aggregators")
+
+    /* Trying shrinking the EOA for the file */
+    if(H5MF__close_shrink_eoa(f, dxpl_id) < 0)
+        HGOTO_ERROR(H5E_RESOURCE, H5E_CANTSHRINK, FAIL, "can't shrink eoa")
+
+    /* Making free-space managers persistent for superblock version >= 2 */
+    if(f->shared->sblock->super_vers >= HDF5_SUPERBLOCK_VERSION_2
+            && f->shared->fs_persist) {
+        H5O_fsinfo_t fsinfo;	/* File space info message */
+        haddr_t final_eoa;      /* Final eoa -- for sanity check */
+        H5F_mem_page_t ptype;   /* Memory type for iteration */
+
+        /* superblock extension and free space manager message should
+         * exist at this point -- verify at least the former.
+         */
+        HDassert(H5F_addr_defined(f->shared->sblock->ext_addr));
+
+        /* file space for all non-empty free space managers should be 
+         * allocated at this point, and these free space managers should
+         * be written to file and thus their headers and section info 
+         * entries in the metadata cache should be clean.
+         */
+
+        /* gather data for the free space manager superblock extension message.
+         *
+         * In passing, verify that all the free space managers are closed.
+         */
+        for(ptype = H5F_MEM_PAGE_META; ptype < H5F_MEM_PAGE_NTYPES; H5_INC_ENUM(H5F_mem_page_t, ptype))
+            fsinfo.fs_addr[ptype - 1] = HADDR_UNDEF;
+        for(type = H5FD_MEM_SUPER; type < H5FD_MEM_NTYPES; H5_INC_ENUM(H5FD_mem_t, type))
+            fsinfo.fs_addr[type-1] = f->shared->fs_addr[type];
+        fsinfo.strategy = f->shared->fs_strategy;
+        fsinfo.persist = f->shared->fs_persist;
+        fsinfo.threshold = f->shared->fs_threshold;
+        fsinfo.page_size = f->shared->fs_page_size;
+        fsinfo.pgend_meta_thres = f->shared->pgend_meta_thres;
+        fsinfo.eoa_pre_fsm_fsalloc = f->shared->eoa_pre_fsm_fsalloc;
+
+        /* Write the free space manager message -- message must already exist */
+        if(H5F_super_ext_write_msg(f, dxpl_id, H5O_FSINFO_ID, &fsinfo, FALSE, H5O_MSG_FLAG_MARK_IF_UNKNOWN) < 0)
+            HGOTO_ERROR(H5E_RESOURCE, H5E_WRITEERROR, FAIL, "error in writing message to superblock extension")
+
+        /* Close the free space managers */
+        for(type = H5FD_MEM_SUPER; type < H5FD_MEM_NTYPES; H5_INC_ENUM(H5FD_mem_t, type)) {
+            if(f->shared->fs_man[type]) {
+                /* test to see if we need to switch rings -- do 
+                 * so if required 
+                 */
+                if(H5MF__fsm_type_is_self_referential(f, (H5F_mem_page_t)type))
+                    needed_ring = H5AC_RING_MDFSM;
+                else 
+                    needed_ring = H5AC_RING_RDFSM;
+
+                if(needed_ring != curr_ring) {
+                    if(H5AC_set_ring(dxpl_id, needed_ring, &dxpl, &curr_ring) < 0)
+                        HGOTO_ERROR(H5E_RESOURCE, H5E_CANTSET, FAIL, "unable to set ring value (1)")
+                    curr_ring = needed_ring;
+                } /* end if */
+
+                HDassert(f->shared->fs_state[type] == H5F_FS_STATE_OPEN);
+
+                if(H5FS_close(f, dxpl_id, f->shared->fs_man[type]) < 0)
+                    HGOTO_ERROR(H5E_RESOURCE, H5E_CANTRELEASE, FAIL, "can't close free space manager")
+                f->shared->fs_man[type] = NULL;
+                f->shared->fs_state[type] = H5F_FS_STATE_CLOSED;
+            } /* end if */
+            f->shared->fs_addr[type] = HADDR_UNDEF;
+        } /* end for */
+
+        /* verify that we haven't dirtied any metadata cache entries
+         * from the metadata free space manager ring out.
+         */
+        HDassert(H5AC_cache_is_clean(f, H5AC_RING_MDFSM));
+
+        /* verify that the aggregators are still shutdown. */
+        HDassert(f->shared->sdata_aggr.tot_size == 0);
+        HDassert(f->shared->sdata_aggr.addr == 0);
+        HDassert(f->shared->sdata_aggr.size == 0);
+
+        HDassert(f->shared->meta_aggr.tot_size == 0);
+        HDassert(f->shared->meta_aggr.addr == 0);
+        HDassert(f->shared->meta_aggr.size == 0);
+
+        /* Trying shrinking the EOA for the file */
+        /* (in case any free space is now at the EOA) */
+        if(H5MF__close_shrink_eoa(f, dxpl_id) < 0)
+            HGOTO_ERROR(H5E_RESOURCE, H5E_CANTSHRINK, FAIL, "can't shrink eoa")
+
+        /* get the eoa, and verify that it has the expected value */
+        if(HADDR_UNDEF == (final_eoa = H5FD_get_eoa(f->shared->lf, H5FD_MEM_DEFAULT)) )
+            HGOTO_ERROR(H5E_FILE, H5E_CANTGET, FAIL, "unable to get file size")
+
+        /* f->shared->eoa_post_fsm_fsalloc is undefined if there has 
+         * been no file space allocation or deallocation since file 
+         * open.
+         */
+        HDassert((f->shared->first_alloc_dealloc) || (final_eoa == f->shared->eoa_post_fsm_fsalloc));
     } /* end if */
+    else {  /* super_vers can be 0, 1, 2 */
+        for(type = H5FD_MEM_DEFAULT; type < H5FD_MEM_NTYPES; H5_INC_ENUM(H5FD_mem_t, type))
+            if(H5MF__close_delete_fstype(f, dxpl_id, (H5F_mem_page_t)type) < 0)
+                HGOTO_ERROR(H5E_RESOURCE, H5E_CANTINIT, FAIL, "can't initialize file free space")
+    } /* end else */
+
+    /* Free the space in aggregators (again) */
+    /* (in case any free space information re-started them) */
+    if(H5MF_free_aggrs(f, dxpl_id) < 0)
+        HGOTO_ERROR(H5E_FILE, H5E_CANTFREE, FAIL, "can't free aggregators")
+
+    /* Trying shrinking the EOA for the file */
+    /* (in case any free space is now at the EOA) */
+    if(H5MF__close_shrink_eoa(f, dxpl_id) < 0)
+        HGOTO_ERROR(H5E_RESOURCE, H5E_CANTSHRINK, FAIL, "can't shrink eoa")
 
 done:
+    /* Reset the ring in the DXPL */
+    if(reset_ring)
+        if(H5AC_reset_ring(dxpl, orig_ring) < 0)
+            HDONE_ERROR(H5E_RESOURCE, H5E_CANTSET, FAIL, "unable to set property value")
 
-    /* Free section node allocated */
-    if(node && H5MF_sect_simple_free((H5FS_section_info_t *)node) < 0)
-        HDONE_ERROR(H5E_RESOURCE, H5E_CANTRELEASE, FAIL, "can't free simple section node")
+#ifdef H5MF_ALLOC_DEBUG
+HDfprintf(stderr, "%s: Leaving\n", FUNC);
+#endif /* H5MF_ALLOC_DEBUG */
+    FUNC_LEAVE_NOAPI_TAG(ret_value, FAIL)
+} /* end H5MF__close_aggrfs() */
 
+
+/*-------------------------------------------------------------------------
+ * Function:    H5MF__close_pagefs
+ *
+ * Purpose:     Close the free space tracker(s) for a file: paged aggregation
+ *
+ * Return:      SUCCEED/FAIL
+ *
+ * Programmer:  Vailin Choi; Dec 2012
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+H5MF__close_pagefs(H5F_t *f, hid_t dxpl_id)
+{
+    H5P_genplist_t *dxpl = NULL;        /* DXPL for setting ring */
+    H5AC_ring_t curr_ring = H5AC_RING_INV;      /* current ring value */
+    H5AC_ring_t needed_ring = H5AC_RING_INV;    /* ring value needed for this
+                                                 * iteration.
+                                                 */
+    H5AC_ring_t orig_ring = H5AC_RING_INV;      /* Original ring value */
+    H5F_mem_page_t ptype; 	/* Memory type for iteration */
+    H5O_fsinfo_t fsinfo;	/* File space info message */
+    hbool_t reset_ring = FALSE; /* Whether the ring was set */
+    herr_t ret_value = SUCCEED;	/* Return value */
+
+    FUNC_ENTER_STATIC_TAG(dxpl_id, H5AC__FREESPACE_TAG, FAIL)
 #ifdef H5MF_ALLOC_DEBUG
-HDfprintf(stderr, "%s: Leaving, ret_value = %d\n", FUNC, ret_value);
+HDfprintf(stderr, "%s: Entering\n", FUNC);
 #endif /* H5MF_ALLOC_DEBUG */
-    FUNC_LEAVE_NOAPI(ret_value)
-} /* end H5MF_try_shrink() */
+
+    /* check args */
+    HDassert(f);
+    HDassert(f->shared);
+    HDassert(f->shared->lf);
+    HDassert(f->shared->sblock);
+    HDassert(f->shared->fs_page_size);
+    HDassert(f->shared->sblock->super_vers >= HDF5_SUPERBLOCK_VERSION_2);
+
+    /* Set the ring type in the DXPL.  In most cases, we will
+     * need H5AC_RING_RDFSM, so initialy set the ring in
+     * the DXPL to that value.  We will alter this later if
+     * needed.
+     */
+    if(H5AC_set_ring(dxpl_id, H5AC_RING_RDFSM, &dxpl, &orig_ring) < 0)
+        HGOTO_ERROR(H5E_RESOURCE, H5E_CANTSET, FAIL, "unable to set ring value")
+    reset_ring = TRUE;
+    curr_ring = H5AC_RING_RDFSM;
+
+    /* Trying shrinking the EOA for the file */
+    if(H5MF__close_shrink_eoa(f, dxpl_id) < 0)
+        HGOTO_ERROR(H5E_RESOURCE, H5E_CANTSHRINK, FAIL, "can't shrink eoa")
+
+    /* Set up file space info message */
+    fsinfo.strategy = f->shared->fs_strategy;
+    fsinfo.persist = f->shared->fs_persist;
+    fsinfo.threshold = f->shared->fs_threshold;
+    fsinfo.page_size = f->shared->fs_page_size;
+    fsinfo.pgend_meta_thres = f->shared->pgend_meta_thres;
+    fsinfo.eoa_pre_fsm_fsalloc = HADDR_UNDEF;
+    for(ptype = H5F_MEM_PAGE_META; ptype < H5F_MEM_PAGE_NTYPES; H5_INC_ENUM(H5F_mem_page_t, ptype))
+        fsinfo.fs_addr[ptype - 1] = HADDR_UNDEF;
+
+    if(f->shared->fs_persist) {
+        haddr_t final_eoa;              /* final eoa -- for sanity check */
+
+        /* superblock extension and free space manager message should
+         * exist at this point -- verify at least the former.
+         */
+        HDassert(H5F_addr_defined(f->shared->sblock->ext_addr));
+
+        /* file space for all non-empty free space managers should be
+         * allocated at this point, and these free space managers should
+         * be written to file and thus their headers and section info
+         * entries in the metadata cache should be clean.
+         */
+
+        /* gather data for the free space manager superblock extension message.
+         * Only need addresses of FSMs and eoa prior to allocation of
+         * file space for the self referential free space managers.  Other 
+         * data was gathered above.
+         */
+        for(ptype = H5F_MEM_PAGE_META; ptype < H5F_MEM_PAGE_NTYPES; H5_INC_ENUM(H5F_mem_page_t, ptype))
+            fsinfo.fs_addr[ptype-1] = f->shared->fs_addr[ptype];
+        fsinfo.eoa_pre_fsm_fsalloc = f->shared->eoa_pre_fsm_fsalloc;
+
+        /* Write the free space manager message -- message must already exist */
+        if(H5F_super_ext_write_msg(f, dxpl_id, H5O_FSINFO_ID, &fsinfo, FALSE, H5O_MSG_FLAG_MARK_IF_UNKNOWN) < 0)
+            HGOTO_ERROR(H5E_RESOURCE, H5E_WRITEERROR, FAIL, "error in writing message to superblock extension")
+
+        /* Close the free space managers */
+        /* use H5MF__close_fstype() for this? */
+        for(ptype = H5F_MEM_PAGE_META; ptype < H5F_MEM_PAGE_NTYPES; H5_INC_ENUM(H5F_mem_page_t, ptype)) {
+            if(f->shared->fs_man[ptype]) {
+                /* test to see if we need to switch rings -- do
+                 * so if required
+                 */
+                if(H5MF__fsm_type_is_self_referential(f, ptype))
+                    needed_ring = H5AC_RING_MDFSM;
+                else
+                    needed_ring = H5AC_RING_RDFSM;
+
+                if(needed_ring != curr_ring) {
+                    if(H5AC_set_ring(dxpl_id, needed_ring, &dxpl, &curr_ring) < 0)
+                        HGOTO_ERROR(H5E_RESOURCE, H5E_CANTSET, FAIL, "unable to set ring value (1)")
+                    curr_ring = needed_ring;
+                } /* end if */
+
+                HDassert(f->shared->fs_state[ptype] == H5F_FS_STATE_OPEN);
+
+                if(H5FS_close(f, dxpl_id, f->shared->fs_man[ptype]) < 0)
+                    HGOTO_ERROR(H5E_RESOURCE, H5E_CANTRELEASE, FAIL, "can't close free space manager")
+                f->shared->fs_man[ptype] = NULL;
+                f->shared->fs_state[ptype] = H5F_FS_STATE_CLOSED;
+            } /* end if */
+            f->shared->fs_addr[ptype] = HADDR_UNDEF;
+        } /* end for */
+
+        /* verify that we haven't dirtied any metadata cache entries
+         * from the metadata free space manager ring out.
+         */
+        HDassert(H5AC_cache_is_clean(f, H5AC_RING_MDFSM));
+
+        /* Trying shrinking the EOA for the file */
+        /* (in case any free space is now at the EOA) */
+        if(H5MF__close_shrink_eoa(f, dxpl_id) < 0)
+            HGOTO_ERROR(H5E_RESOURCE, H5E_CANTSHRINK, FAIL, "can't shrink eoa")
+
+        /* get the eoa, and verify that it has the expected value */
+        if(HADDR_UNDEF == (final_eoa = H5FD_get_eoa(f->shared->lf, H5FD_MEM_DEFAULT)) )
+            HGOTO_ERROR(H5E_FILE, H5E_CANTGET, FAIL, "unable to get file size")
+
+        /* f->shared->eoa_post_fsm_fsalloc is undefined if there has
+         * been no file space allocation or deallocation since file
+         * open.
+         *
+         * If there is a cache image in the file at file open, 
+         * f->shared->first_alloc_dealloc will always be FALSE unless 
+         * the file is opened R/O, as otherwise, the image will have been
+         * read and discarded by this point.
+         *
+         * If a cache image was created on file close, the actual EOA 
+         * should be in f->shared->eoa_post_mdci_fsalloc.  Note that in 
+         * this case, it is conceivable that f->shared->first_alloc_dealloc
+         * will still be TRUE, as the cache image is allocated directly from
+         * the file driver layer.  However, as this possibility seems remote,
+         * it is ignored in the following assert.
+         */
+        HDassert((f->shared->first_alloc_dealloc) ||
+                 (final_eoa == f->shared->eoa_post_fsm_fsalloc) ||
+                 ((H5F_addr_defined(f->shared->eoa_post_mdci_fsalloc)) &&
+                  (final_eoa == f->shared->eoa_post_mdci_fsalloc)));
+    } /* end if */
+    else {
+        /* Iterate over all the free space types that have managers 
+         * and get each free list's space 
+         */
+        for(ptype = H5F_MEM_PAGE_META; ptype < H5F_MEM_PAGE_NTYPES; H5_INC_ENUM(H5F_mem_page_t, ptype))
+            if(H5MF__close_delete_fstype(f, dxpl_id, ptype) < 0)
+                HGOTO_ERROR(H5E_RESOURCE, H5E_CANTRELEASE, FAIL, "can't close the free space manager")
+
+        /* Write file space info message to superblock extension object header */
+        /* Create the superblock extension object header in advance if needed */
+        if(H5F_super_ext_write_msg(f, dxpl_id, H5O_FSINFO_ID, &fsinfo, FALSE, H5O_MSG_FLAG_MARK_IF_UNKNOWN) < 0)
+            HGOTO_ERROR(H5E_RESOURCE, H5E_WRITEERROR, FAIL, "error in writing message to superblock extension")
+    } /* end else */
+
+    /* Trying shrinking the EOA for the file */
+    /* (in case any free space is now at the EOA) */
+    if(H5MF__close_shrink_eoa(f, dxpl_id) < 0)
+        HGOTO_ERROR(H5E_RESOURCE, H5E_CANTSHRINK, FAIL, "can't shrink eoa")
+
+done:
+    /* Reset the ring in the DXPL */
+    if(reset_ring)
+        if(H5AC_reset_ring(dxpl, orig_ring) < 0)
+            HDONE_ERROR(H5E_RESOURCE, H5E_CANTSET, FAIL, "unable to set property value")
+
+#ifdef H5MF_ALLOC_DEBUG
+HDfprintf(stderr, "%s: Leaving\n", FUNC);
+#endif /* H5MF_ALLOC_DEBUG */
+    FUNC_LEAVE_NOAPI_TAG(ret_value, FAIL)
+} /* end H5MF__close_pagefs() */
 
 
 /*-------------------------------------------------------------------------
@@ -1175,17 +2188,16 @@ HDfprintf(stderr, "%s: Leaving, ret_value = %d\n", FUNC, ret_value);
 static herr_t
 H5MF__close_shrink_eoa(H5F_t *f, hid_t dxpl_id)
 {
-    H5FD_mem_t type;            /* Memory type for iteration */
     H5P_genplist_t *dxpl = NULL;        /* DXPL for setting ring */
+    H5AC_ring_t curr_ring = H5AC_RING_INV;      /* Current ring value */
+    H5AC_ring_t needed_ring = H5AC_RING_INV;    /* Ring value needed for this iteration.  */
     H5AC_ring_t orig_ring = H5AC_RING_INV;      /* Original ring value */
-    H5AC_ring_t curr_ring = H5AC_RING_INV;      /* current ring value */
-    H5AC_ring_t needed_ring = H5AC_RING_INV;    /* ring value needed for this
-                                                 * iteration.
-                                                 */
+    H5F_mem_t type;
+    H5F_mem_page_t ptype;        /* Memory type for iteration */
     hbool_t eoa_shrank;		/* Whether an EOA shrink occurs */
-    hbool_t reset_ring = FALSE; /* Whether the ring was set */
     htri_t status;		/* Status value */
     H5MF_sect_ud_t udata;	/* User data for callback */
+    hbool_t reset_ring = FALSE; /* Whether the ring was set */
     herr_t ret_value = SUCCEED;	/* Return value */
 
     FUNC_ENTER_STATIC_TAG(dxpl_id, H5AC__FREESPACE_TAG, FAIL)
@@ -1197,13 +2209,10 @@ H5MF__close_shrink_eoa(H5F_t *f, hid_t dxpl_id)
     /* Construct user data for callbacks */
     udata.f = f;
     udata.dxpl_id = dxpl_id;
-    udata.allow_sect_absorb = FALSE;    
-    udata.allow_eoa_shrink_only = TRUE; 
+    udata.allow_sect_absorb = FALSE;
+    udata.allow_eoa_shrink_only = TRUE;
 
-    /* Set the ring type in the DXPL.  In most cases, we will 
-     * need H5AC_RING_RDFSM, so initialy set the ring type in 
-     * the DXPL to that value.  We will alter this later if needed.
-     */
+    /* Set the ring type in the DXPL */
     if(H5AC_set_ring(dxpl_id, H5AC_RING_RDFSM, &dxpl, &orig_ring) < 0)
         HGOTO_ERROR(H5E_RESOURCE, H5E_CANTSET, FAIL, "unable to set ring value(1)")
     reset_ring = TRUE;
@@ -1213,36 +2222,62 @@ H5MF__close_shrink_eoa(H5F_t *f, hid_t dxpl_id)
     do {
 	eoa_shrank = FALSE;
 
-	/* Check the last section of each free-space manager */
-	for(type = H5FD_MEM_DEFAULT; type < H5FD_MEM_NTYPES; H5_INC_ENUM(H5FD_mem_t, type)) {
+        if(H5F_PAGED_AGGR(f)) {
+            /* Check the last section of each free-space manager */
+            for(ptype = H5F_MEM_PAGE_META; ptype < H5F_MEM_PAGE_NTYPES; H5_INC_ENUM(H5F_mem_page_t, ptype)) {
+                if(f->shared->fs_man[ptype]) {
+                    /* Test to see if we need to switch rings -- do so if required */
+                    if(H5MF__fsm_type_is_self_referential(f, ptype))
+                        needed_ring = H5AC_RING_MDFSM;
+                    else
+                        needed_ring = H5AC_RING_RDFSM;
 
-            /* test to see if we need to switch rings -- do so if required */
-            if((H5MF_ALLOC_TO_FS_TYPE(f, type) == H5MF_ALLOC_TO_FS_TYPE(f, H5FD_MEM_FSPACE_HDR))
-                    || (H5MF_ALLOC_TO_FS_TYPE(f, type) == H5MF_ALLOC_TO_FS_TYPE(f, H5FD_MEM_FSPACE_SINFO)))
-                needed_ring = H5AC_RING_MDFSM;
-            else
-                needed_ring = H5AC_RING_RDFSM;
+                    if(needed_ring != curr_ring) {
+                        if(H5AC_set_ring(dxpl_id, needed_ring, &dxpl, &curr_ring) < 0)
+                            HGOTO_ERROR(H5E_RESOURCE, H5E_CANTSET, FAIL, "unable to set ring value (1)")
+                        curr_ring = needed_ring;
+                    } /* end if */
 
-            if(needed_ring != curr_ring) {
-                if(H5AC_set_ring(dxpl_id, needed_ring, &dxpl, &curr_ring) < 0)
-                    HGOTO_ERROR(H5E_RESOURCE, H5E_CANTSET, FAIL, "unable to set ring value (2)")
-                curr_ring = needed_ring;
-            } /* end if */
+                    udata.alloc_type = (H5FD_mem_t)((H5FD_mem_t)ptype < H5FD_MEM_NTYPES ? ptype : ((ptype % H5FD_MEM_NTYPES) + 1));
 
-	    if(f->shared->fs_man[type]) {
-		udata.alloc_type = type;
-		if((status = H5FS_sect_try_shrink_eoa(f, dxpl_id, f->shared->fs_man[type], &udata)) < 0)
-		    HGOTO_ERROR(H5E_RESOURCE, H5E_CANTSHRINK, FAIL, "can't check for shrinking eoa")
-		else if(status > 0)
-		    eoa_shrank = TRUE;
-	    } /* end if */
-	} /* end for */
+                    if((status = H5FS_sect_try_shrink_eoa(f, dxpl_id, f->shared->fs_man[ptype], &udata)) < 0)
+                        HGOTO_ERROR(H5E_RESOURCE, H5E_CANTSHRINK, FAIL, "can't check for shrinking eoa")
+                    else if(status > 0)
+                        eoa_shrank = TRUE;
+                } /* end if */
+            } /* end for */
+        } /* end if */
+        else {
+            /* Check the last section of each free-space manager */
+            for(type = H5FD_MEM_DEFAULT; type < H5FD_MEM_NTYPES; H5_INC_ENUM(H5FD_mem_t, type)) {
+                if(f->shared->fs_man[type]) {
+                    /* Test to see if we need to switch rings -- do so if required */
+                    if(H5MF__fsm_type_is_self_referential(f, (H5F_mem_page_t)type))
+                        needed_ring = H5AC_RING_MDFSM;
+                    else
+                        needed_ring = H5AC_RING_RDFSM;
+
+                    if(needed_ring != curr_ring) {
+                        if(H5AC_set_ring(dxpl_id, needed_ring, &dxpl, &curr_ring) < 0)
+                            HGOTO_ERROR(H5E_RESOURCE, H5E_CANTSET, FAIL, "unable to set ring value (1)")
+                        curr_ring = needed_ring;
+                    } /* end if */
+
+                    udata.alloc_type = type;
 
-	/* check the two aggregators */
-	if((status = H5MF_aggrs_try_shrink_eoa(f, dxpl_id)) < 0)
-	    HGOTO_ERROR(H5E_RESOURCE, H5E_CANTSHRINK, FAIL, "can't check for shrinking eoa")
-	else if(status > 0)
-	    eoa_shrank = TRUE;
+                    if((status = H5FS_sect_try_shrink_eoa(f, dxpl_id, f->shared->fs_man[type], &udata)) < 0)
+                        HGOTO_ERROR(H5E_RESOURCE, H5E_CANTSHRINK, FAIL, "can't check for shrinking eoa")
+                else if(status > 0)
+                    eoa_shrank = TRUE;
+                } /* end if */
+            } /* end for */
+
+            /* check the two aggregators */
+            if((status = H5MF_aggrs_try_shrink_eoa(f, dxpl_id)) < 0)
+                HGOTO_ERROR(H5E_RESOURCE, H5E_CANTSHRINK, FAIL, "can't check for shrinking eoa")
+            else if(status > 0)
+                eoa_shrank = TRUE;
+        } /* end else */
     } while(eoa_shrank);
 
 done:
@@ -1256,6 +2291,370 @@ done:
 
 
 /*-------------------------------------------------------------------------
+ * Function:    H5MF_get_freespace
+ *
+ * Purpose:     Retrieve the amount of free space in the file
+ *
+ * Return:      Success:        Amount of free space in file
+ *              Failure:        Negative
+ *
+ * Programmer:  Quincey Koziol
+ *              Monday, October  6, 2003
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5MF_get_freespace(H5F_t *f, hid_t dxpl_id, hsize_t *tot_space, hsize_t *meta_size)
+{
+    haddr_t ma_addr = HADDR_UNDEF;  /* Base "metadata aggregator" address */
+    hsize_t ma_size = 0;            /* Size of "metadata aggregator" */
+    haddr_t sda_addr = HADDR_UNDEF; /* Base "small data aggregator" address */
+    hsize_t sda_size = 0;           /* Size of "small data aggregator" */
+    hsize_t tot_fs_size = 0;        /* Amount of all free space managed */
+    hsize_t tot_meta_size = 0;      /* Amount of metadata for free space managers */
+    H5FD_mem_t tt;                  /* Memory type for iteration */
+    H5F_mem_page_t type;            /* Memory type for iteration */
+    H5F_mem_page_t start_type;      /* Memory type for iteration */
+    H5F_mem_page_t end_type;        /* Memory type for iteration */
+    htri_t fs_started[H5F_MEM_PAGE_NTYPES]; /* Indicate whether the free-space manager has been started */
+    haddr_t fs_eoa[H5FD_MEM_NTYPES];        /* EAO for each free-space manager */
+    H5P_genplist_t *dxpl = NULL;            /* DXPL for setting ring */
+    H5AC_ring_t curr_ring = H5AC_RING_INV;      /* Current ring value */
+    H5AC_ring_t needed_ring = H5AC_RING_INV;    /* Ring value needed for this iteration.  */
+    H5AC_ring_t orig_ring = H5AC_RING_INV;  /* Original ring value */
+    hbool_t reset_ring = FALSE;             /* Whether the ring was set */
+    herr_t ret_value = SUCCEED;             /* Return value */
+
+    FUNC_ENTER_NOAPI_TAG(dxpl_id, H5AC__FREESPACE_TAG, FAIL)
+
+    /* check args */
+    HDassert(f);
+    HDassert(f->shared);
+    HDassert(f->shared->lf);
+
+    /* Set the ring type in the DXPL.  In most cases, we will
+     * need H5AC_RING_RDFSM, so initialy set the ring in
+     * the DXPL to that value.  We will alter this later if
+     * needed.
+     */
+    if(H5AC_set_ring(dxpl_id, H5AC_RING_RDFSM, &dxpl, &orig_ring) < 0)
+        HGOTO_ERROR(H5E_RESOURCE, H5E_CANTSET, FAIL, "unable to set ring value")
+    reset_ring = TRUE;
+    curr_ring = H5AC_RING_RDFSM;
+
+    /* Determine start/end points for loop */
+    if(H5F_PAGED_AGGR(f)) {
+        start_type = H5F_MEM_PAGE_META;
+        end_type = H5F_MEM_PAGE_NTYPES;
+    } /* end if */
+    else {
+        start_type = (H5F_mem_page_t)H5FD_MEM_SUPER;
+        end_type = (H5F_mem_page_t)H5FD_MEM_NTYPES;
+    } /* end else */
+
+    for(tt = H5FD_MEM_SUPER; tt < H5FD_MEM_NTYPES; H5_INC_ENUM(H5FD_mem_t, tt))
+        if(HADDR_UNDEF == (fs_eoa[tt] = H5F_get_eoa(f, tt)))
+            HGOTO_ERROR(H5E_RESOURCE, H5E_CANTGET, FAIL, "driver get_eoa request failed")
+
+    if(!H5F_PAGED_AGGR(f)) {
+        /* Retrieve metadata aggregator info, if available */
+        if(H5MF_aggr_query(f, &(f->shared->meta_aggr), &ma_addr, &ma_size) < 0)
+            HGOTO_ERROR(H5E_RESOURCE, H5E_CANTGET, FAIL, "can't query metadata aggregator stats")
+
+        /* Retrieve 'small data' aggregator info, if available */
+        if(H5MF_aggr_query(f, &(f->shared->sdata_aggr), &sda_addr, &sda_size) < 0)
+            HGOTO_ERROR(H5E_RESOURCE, H5E_CANTGET, FAIL, "can't query small data aggregator stats")
+    } /* end if */
+
+    /* Iterate over all the free space types that have managers and get each free list's space */
+    for(type = start_type; type < end_type; H5_INC_ENUM(H5F_mem_page_t, type)) {
+        fs_started[type] = FALSE;
+
+        /* Check if the free space for the file has been initialized */
+        if(!f->shared->fs_man[type] && H5F_addr_defined(f->shared->fs_addr[type])) {
+            if(H5MF_open_fstype(f, dxpl_id, type) < 0)
+                HGOTO_ERROR(H5E_RESOURCE, H5E_CANTINIT, FAIL, "can't initialize file free space")
+            HDassert(f->shared->fs_man[type]);
+            fs_started[type] = TRUE;
+        } /* end if */
+
+        /* test to see if we need to switch rings -- do
+         * so if required
+         */
+        if(H5MF__fsm_type_is_self_referential(f, (H5F_mem_page_t)type))
+            needed_ring = H5AC_RING_MDFSM;
+        else
+            needed_ring = H5AC_RING_RDFSM;
+
+        if(needed_ring != curr_ring) {
+            if(H5AC_set_ring(dxpl_id, needed_ring, &dxpl, &curr_ring) < 0)
+                HGOTO_ERROR(H5E_RESOURCE, H5E_CANTSET, FAIL, "unable to set ring value")
+            curr_ring = needed_ring;
+        } /* end if */
+
+        /* Check if there's free space of this type */
+        if(f->shared->fs_man[type]) {
+            hsize_t type_fs_size = 0;    /* Amount of free space managed for each type */
+            hsize_t type_meta_size = 0;  /* Amount of free space metadata for each type */
+
+            /* Retrieve free space size from free space manager */
+            if(H5FS_sect_stats(f->shared->fs_man[type], &type_fs_size, NULL) < 0)
+                HGOTO_ERROR(H5E_RESOURCE, H5E_CANTGET, FAIL, "can't query free space stats")
+            if(H5FS_size(f, f->shared->fs_man[type], &type_meta_size) < 0)
+                HGOTO_ERROR(H5E_RESOURCE, H5E_CANTGET, FAIL, "can't query free space metadata stats")
+
+            /* Increment total free space for types */
+            tot_fs_size += type_fs_size;
+            tot_meta_size += type_meta_size;
+        } /* end if */
+    } /* end for */
+
+    /* Close the free-space managers if they were opened earlier in this routine */
+    for(type = start_type; type < end_type; H5_INC_ENUM(H5F_mem_page_t, type)) {
+        /* Test to see if we need to switch rings -- do so if required */
+        if(H5MF__fsm_type_is_self_referential(f, (H5F_mem_page_t)type))
+            needed_ring = H5AC_RING_MDFSM;
+        else
+            needed_ring = H5AC_RING_RDFSM;
+
+        if(needed_ring != curr_ring) {
+            if(H5AC_set_ring(dxpl_id, needed_ring, &dxpl, &curr_ring) < 0)
+                HGOTO_ERROR(H5E_RESOURCE, H5E_CANTSET, FAIL, "unable to set ring value")
+            curr_ring = needed_ring;
+        } /* end if */
+
+        if(fs_started[type])
+            if(H5MF__close_fstype(f, dxpl_id, type) < 0)
+                HGOTO_ERROR(H5E_RESOURCE, H5E_CANTINIT, FAIL, "can't close file free space")
+    } /* end for */
+
+    /* Set the value(s) to return */
+    /* (The metadata & small data aggregators count as free space now, since they aren't at EOA) */
+    if(tot_space)
+        *tot_space = tot_fs_size + ma_size + sda_size;
+    if(meta_size)
+        *meta_size = tot_meta_size;
+
+done:
+    /* Reset the ring in the DXPL */
+    if(reset_ring)
+        if(H5AC_reset_ring(dxpl, orig_ring) < 0)
+            HDONE_ERROR(H5E_RESOURCE, H5E_CANTSET, FAIL, "unable to set property value")
+
+    FUNC_LEAVE_NOAPI_TAG(ret_value, FAIL)
+} /* end H5MF_get_freespace() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:    H5MF_get_free_sections()
+ *
+ * Purpose: 	To retrieve free-space section information for
+ *              paged or non-paged aggregation
+ *
+ * Return:      SUCCEED/FAIL
+ *
+ * Programmer:  Vailin Choi; Dec 2012
+ *
+ *-------------------------------------------------------------------------
+ */
+ssize_t
+H5MF_get_free_sections(H5F_t *f, hid_t dxpl_id, H5FD_mem_t type, size_t nsects, H5F_sect_info_t *sect_info)
+{
+    H5P_genplist_t *dxpl = NULL;                /* DXPL for setting ring */
+    H5AC_ring_t curr_ring = H5AC_RING_INV;      /* Current ring value */
+    H5AC_ring_t needed_ring = H5AC_RING_INV;    /* Ring value needed for this iteration.  */
+    H5AC_ring_t orig_ring = H5AC_RING_INV;      /* Original ring value */
+    size_t total_sects = 0;                     /* Total number of sections */
+    H5MF_sect_iter_ud_t sect_udata;             /* User data for callback */
+    H5F_mem_page_t start_type, end_type;        /* Memory types to iterate over */
+    H5F_mem_page_t ty;                          /* Memory type for iteration */
+    hbool_t reset_ring = FALSE;                 /* Whether the ring was set */
+    ssize_t ret_value = -1;                     /* Return value */
+
+    FUNC_ENTER_NOAPI_TAG(dxpl_id, H5AC__FREESPACE_TAG, -1)
+
+    /* check args */
+    HDassert(f);
+    HDassert(f->shared);
+    HDassert(f->shared->lf);
+
+    /* H5MF_tidy_self_referential_fsm_hack() will fail if any self 
+     * referential FSM is opened prior to the call to it.  Thus call
+     * it here if necessary and if it hasn't been called already.
+     *
+     * The situation is further complicated if a cache image exists
+     * and had not yet been loaded into the metadata cache.  In this
+     * case, call H5AC_force_cache_image_load() instead of 
+     * H5MF_tidy_self_referential_fsm_hack().  H5AC_force_cache_image_load()
+     * will load the cache image, and then call 
+     * H5MF_tidy_self_referential_fsm_hack() to discard the cache image 
+     * block.
+     */
+    if(f->shared->first_alloc_dealloc) {
+        if(H5AC_cache_image_pending(f)) {
+            if(H5AC_force_cache_image_load(f, dxpl_id) < 0)
+                HGOTO_ERROR(H5E_RESOURCE, H5E_CANTFREE, FAIL, "forced cache image load failed")
+        } /* end if */
+        else {
+            if(H5MF_tidy_self_referential_fsm_hack(f, dxpl_id) < 0)
+                HGOTO_ERROR(H5E_RESOURCE, H5E_CANTFREE, FAIL, "tidy of self referential fsm hack failed")
+        } /* end else */
+    } /* end if */
+
+    if(type == H5FD_MEM_DEFAULT) {
+        start_type = H5F_MEM_PAGE_SUPER;
+        end_type = H5F_MEM_PAGE_NTYPES;
+    } /* end if */
+    else {
+        start_type = end_type = (H5F_mem_page_t)type;
+        if(H5F_PAGED_AGGR(f)) /* set to the corresponding LARGE free-space manager */
+            end_type = (H5F_mem_page_t)(end_type + H5FD_MEM_NTYPES);
+        else
+            H5_INC_ENUM(H5F_mem_page_t, end_type);
+    } /* end else */
+
+    /* Set up user data for section iteration */
+    sect_udata.sects = sect_info;
+    sect_udata.sect_count = nsects;
+    sect_udata.sect_idx = 0;
+
+    /* Set the ring type in the DXPL.  In most cases, we will
+     * need H5AC_RING_RDFSM, so initialy set the ring in
+     * the DXPL to that value.  We will alter this later if
+     * needed.
+     */
+    if(H5AC_set_ring(dxpl_id, H5AC_RING_RDFSM, &dxpl, &orig_ring) < 0)
+        HGOTO_ERROR(H5E_RESOURCE, H5E_CANTSET, FAIL, "unable to set ring value(0)")
+    reset_ring = TRUE;
+    curr_ring = H5AC_RING_RDFSM;
+
+    /* Iterate over memory types, retrieving the number of sections of each type */
+    for(ty = start_type; ty < end_type; H5_INC_ENUM(H5F_mem_page_t, ty)) {
+        hbool_t fs_started = FALSE;	/* The free-space manager is opened or not */
+        size_t nums = 0;		/* The number of free-space sections */
+
+        /* Test to see if we need to switch rings -- do so if required */
+        if(H5MF__fsm_type_is_self_referential(f, ty))
+            needed_ring = H5AC_RING_MDFSM;
+        else
+            needed_ring = H5AC_RING_RDFSM;
+
+        if(needed_ring != curr_ring) {
+            if(H5AC_set_ring(dxpl_id, needed_ring, &dxpl, &curr_ring) < 0)
+                HGOTO_ERROR(H5E_RESOURCE, H5E_CANTSET, FAIL, "unable to set ring value (1)")
+            curr_ring = needed_ring;
+        } /* end if */
+
+        if(!f->shared->fs_man[ty] && H5F_addr_defined(f->shared->fs_addr[ty])) {
+            if(H5MF_open_fstype(f, dxpl_id, ty) < 0)
+                HGOTO_ERROR(H5E_RESOURCE, H5E_CANTRELEASE, FAIL, "can't open the free space manager")
+            HDassert(f->shared->fs_man[ty]);
+            fs_started = TRUE;
+        } /* end if */
+
+        /* Check if there's free space sections of this type */
+        if(f->shared->fs_man[ty])
+            if(H5MF__get_free_sects(f, dxpl_id, f->shared->fs_man[ty], &sect_udata, &nums) < 0)
+                HGOTO_ERROR(H5E_RESOURCE, H5E_CANTRELEASE, FAIL, "can't get section info for the free space manager")
+
+        /* Increment total # of sections */
+        total_sects += nums;
+
+        /* Close the free space manager of this type, if we started it here */
+        if(fs_started)
+            if(H5MF__close_fstype(f, dxpl_id, ty) < 0)
+                HGOTO_ERROR(H5E_RESOURCE, H5E_CANTCLOSEOBJ, FAIL, "can't close file free space")
+        if((H5F_PAGED_AGGR(f)) && (type != H5FD_MEM_DEFAULT))
+            ty = (H5F_mem_page_t)(ty + H5FD_MEM_NTYPES - 2);
+    } /* end for */
+
+    /* Set return value */
+    ret_value = (ssize_t)total_sects;
+
+done:
+    /* Reset the ring in the DXPL */
+    if(reset_ring)
+        if(H5AC_reset_ring(dxpl, orig_ring) < 0)
+            HDONE_ERROR(H5E_RESOURCE, H5E_CANTSET, FAIL, "unable to set property value")
+
+    FUNC_LEAVE_NOAPI_TAG(ret_value, -1)
+} /* H5MF_get_free_sections() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:    H5MF_sects_cb()
+ *
+ * Purpose:	Iterator callback for each free-space section
+ *          Retrieve address and size into user data
+ *
+ * Return:	Always succeed
+ *
+ * Programmer:  Vailin Choi
+ *              July 1st, 2009
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+H5MF_sects_cb(H5FS_section_info_t *_sect, void *_udata)
+{
+    H5MF_free_section_t *sect = (H5MF_free_section_t *)_sect;
+    H5MF_sect_iter_ud_t *udata = (H5MF_sect_iter_ud_t *)_udata;
+
+    FUNC_ENTER_NOAPI_NOINIT_NOERR
+
+    if(udata->sect_idx < udata->sect_count) {
+        udata->sects[udata->sect_idx].addr = sect->sect_info.addr;
+        udata->sects[udata->sect_idx].size  = sect->sect_info.size;
+        udata->sect_idx++;
+    } /* end if */
+
+    FUNC_LEAVE_NOAPI(SUCCEED)
+} /* H5MF_sects_cb() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:    H5MF__get_free_sects
+ *
+ * Purpose:	Retrieve section information for the specified free-space manager.
+ *
+ * Return:      Success:        non-negative
+ *              Failure:        negative
+ *
+ * Programmer:  Vailin Choi; Dec 2012
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+H5MF__get_free_sects(H5F_t *f, hid_t dxpl_id, H5FS_t *fspace, H5MF_sect_iter_ud_t *sect_udata, size_t *nums)
+{
+    hsize_t hnums = 0;          	/* # of sections */
+    herr_t ret_value = SUCCEED; 	/* Return value */
+
+    FUNC_ENTER_NOAPI(FAIL)
+
+    /* check args */
+    HDassert(f);
+    HDassert(sect_udata);
+    HDassert(nums);
+    HDassert(fspace);
+
+    /* Query how many sections of this type */
+    if(H5FS_sect_stats(fspace, NULL, &hnums) < 0)
+        HGOTO_ERROR(H5E_RESOURCE, H5E_CANTGET, FAIL, "can't query free space stats")
+    H5_CHECKED_ASSIGN(*nums, size_t, hnums, hsize_t);
+
+    /* Check if we should retrieve the section info */
+    if(sect_udata->sects && *nums > 0)
+        /* Iterate over all the free space sections of this type, adding them to the user's section info */
+        if(H5FS_sect_iterate(f, dxpl_id, fspace, H5MF_sects_cb, sect_udata) < 0)
+            HGOTO_ERROR(H5E_RESOURCE, H5E_BADITER, FAIL, "can't iterate over sections")
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* H5MF__get_free_sects() */
+
+
+/*-------------------------------------------------------------------------
  * Function:    H5MF_settle_raw_data_fsm()
  *
  * Purpose: 	Handle any tasks required before the metadata cache 
@@ -1263,19 +2662,48 @@ done:
  *		and any metadata free space managers that reside in the 
  *		raw data free space manager ring.
  *
- *		Specifically, any metadata managers that DON'T handle 
- *		space allocation for free space manager header or section
- *		info will reside in the raw data free space manager ring.
- *		As of this writing, the plan is to move to only two free space
- *		managers, one for raw data and one for metadata -- which
- *		means that only the raw data free space manager will reside
- *		in the free space manager ring.  However, this has not been
- *		fully implemented yet, so this code must support the 
- *		possibilty of multiple metadata free space managers, at most
- *		two of which handle free space manager header or section info,
- *		and thus reside in the metadata free space manager ring.
- *
- *		At present, the task list is:
+ *              Specifically, this means any metadata managers that DON'T 
+ *              handle space allocation for free space manager header or 
+ *              section info will reside in the raw data free space manager 
+ *              ring.
+ *
+ *              In the absence of page allocation, there is at most one 
+ *		free space manager per memory type defined in H5F_mem_t.
+ *		Of these, the one that allocates H5FD_MEM_DRAW will 
+ *		always reside in the raw data free space manager ring.
+ *		If there is more than one metadata free space manager, 
+ *		all that don't handle H5FD_MEM_FSPACE_HDR or 
+ *              H5FD_MEM_FSPACE_SINFO (which map to H5FD_MEM_OHDR and 
+ *              H5FD_MEM_LHEAP respectively) will reside in the raw 
+ *		data free space manager ring as well
+ *
+ *		With page allocation, the situation is conceptually 
+ *		identical, but more complex in practice.
+ *
+ *              In the worst case (multi file driver) page allocation 
+ *		can result in two free space managers for each memory 
+ *		type -- one for small (less than on equal to one page)
+ *              allocations, and one for large (greater than one page)
+ *              allocations.
+ *
+ *		In the more common one file case, page allocation will
+ *              result in a total of three free space managers -- one for 
+ *              small (<= one page) raw data allocations, one for small 
+ *              metadata allocations (i.e, all memory types other than 
+ *              H5FD_MEM_DRAW), and one for all large (> one page) 
+ *              allocations.
+ *
+ *              Despite these complications, the solution is the same in
+ *		the page allocation case -- free space managers (be they 
+ *              small data or large) are assigned to the raw data free 
+ *              space manager ring if they don't allocate file space for
+ *              free space managers.  Note that in the one file case, the 
+ *		large free space manager must be assigned to the metadata
+ *		free space manager ring, as it both allocates pages for 
+ *		the metadata free space manager, and allocates space for 
+ *		large (> 1 page) metadata cache entries.
+ *
+ *              At present, the task list for this routine is:
  *
  *		1) Reduce the EOA to the extent possible.  To do this:
  *
@@ -1330,26 +2758,43 @@ done:
 herr_t
 H5MF_settle_raw_data_fsm(H5F_t *f, hid_t dxpl_id, hbool_t *fsm_settled)
 {
+    int pass_count;
+    hsize_t alloc_size;
+    H5F_mem_t mem_type;                 /* Memory type for iteration */
+    H5F_mem_page_t fsm_type;            /* FSM type for iteration */
+    H5O_fsinfo_t fsinfo;                /* Free space manager info message */
+    H5FS_stat_t fs_stat;                /* Information for free-space manager */
     H5P_genplist_t *dxpl = NULL;        /* DXPL for setting ring */
     H5AC_ring_t orig_ring = H5AC_RING_INV;      /* Original ring value */
+    H5AC_ring_t curr_ring = H5AC_RING_INV;      /* Current ring value */
+    H5AC_ring_t needed_ring = H5AC_RING_INV;    /* Ring value needed for this iteration */
     hbool_t reset_ring = FALSE;         /* Whether the ring was set */
     herr_t ret_value = SUCCEED;         /* Return value */
 
     FUNC_ENTER_NOAPI_TAG(dxpl_id, H5AC__FREESPACE_TAG, FAIL)
 
-    /* check args */
+    /* Check args */
     HDassert(f);
     HDassert(f->shared);
     HDassert(fsm_settled);
 
-    /* Only need to settle things if we are persisting the free space info */
-    if(f->shared->fs_strategy == H5F_FILE_SPACE_ALL_PERSIST) {
-        H5O_fsinfo_t fsinfo;                    /* Free space manager info message */
-        H5FD_mem_t	type;			/* Memory type for iteration */
-        H5AC_ring_t curr_ring = H5AC_RING_INV;  /* Current ring value */
-        H5AC_ring_t needed_ring = H5AC_RING_INV; /* Ring value needed for this iteration  */
-        hbool_t fsm_opened[H5FD_MEM_NTYPES];    /* State of FSM */
-        hbool_t fsm_visited[H5FD_MEM_NTYPES];   /* State of FSM */
+    /* Only need to settle things if we are persisting the free space info 
+     * and allocation/deallocation has occurred.
+     */
+    if(f->shared->fs_persist && !f->shared->first_alloc_dealloc) {
+        hbool_t fsm_opened[H5F_MEM_PAGE_NTYPES];        /* State of FSM */
+        hbool_t fsm_visited[H5F_MEM_PAGE_NTYPES];       /* State of FSM */
+
+        /* Sanity check */
+        HDassert(f->shared->sblock);
+
+        /* should only be called if file is opened R/W */
+        HDassert(H5F_INTENT(f) & H5F_ACC_RDWR);
+
+        /* shouldn't be called unless we have a superblock supporting the
+         * superblock extension.
+         */
+        HDassert(f->shared->sblock->super_vers >= HDF5_SUPERBLOCK_VERSION_2);
 
         /* Initialize fsm_opened and fsm_visited */
         HDmemset(fsm_opened, 0, sizeof(fsm_opened));
@@ -1366,8 +2811,12 @@ H5MF_settle_raw_data_fsm(H5F_t *f, hid_t dxpl_id, hbool_t *fsm_settled)
          *
          * Note that while the raw data aggregator should not be restarted during
          * the close process, this need not be the case for the metadata aggregator.
+         *
+         * Note also that the aggregators will not exist if page aggregation 
+         * is enabled -- skip this if so.
          */
-        if(H5MF_free_aggrs(f, dxpl_id) < 0)
+        /* Vailin -- is this correct? */
+        if(!H5F_PAGED_AGGR(f) && (H5MF_free_aggrs(f, dxpl_id) < 0))
             HGOTO_ERROR(H5E_RESOURCE, H5E_CANTFREE, FAIL, "can't free aggregators")
 
         /* Set the ring type in the DXPL.  In most cases, we will
@@ -1389,7 +2838,7 @@ H5MF_settle_raw_data_fsm(H5F_t *f, hid_t dxpl_id, hbool_t *fsm_settled)
          * In the case of the raw data free space manager, and any other free
          * space manager that does not allocate space for free space managers,
          * allocations should be complete at this point, as all raw data should
-         * have space allocated and be flushed to file at this point.  Thus we
+         * have space allocated and be flushed to file by now.  Thus we
          * can examine such free space managers and only re-allocate space for
          * them if they contain free space.  Do this later in this function after
          * the EOA has been reduced to the extent possible.
@@ -1400,79 +2849,100 @@ H5MF_settle_raw_data_fsm(H5F_t *f, hid_t dxpl_id, hbool_t *fsm_settled)
          * are possible), the matter is more ticklish due to the self-
          * referential nature of the problem.  These FSMs are dealt with in
          * H5MF_settle_meta_data_fsm().
+         *
+         * Since paged allocation may be enabled, there may be up to two 
+         * free space managers per memory type -- one for small and one for
+         * large allocation.  Hence we must loop over the memory types twice
+         * setting the allocation size accordingly if paged allocation is 
+         * enabled.
          */
-        for(type = H5FD_MEM_SUPER; type < H5FD_MEM_NTYPES; H5_INC_ENUM(H5FD_mem_t, type)) {
-            H5FS_stat_t fs_stat;        /* Information for free-space manager */
-            H5FD_mem_t  fsm_type;       /* File memory type for FSM */
-
-            /* There is potentially a many-to-one mapping from memory types to 
-             * free space managers.  Use the fsm_visited[] array to avoid visiting 
-             * a given FSM more than once.  Use fsm_opened[] to track which FSMs
-             * must be closed at the end of this function.
-             */
-            fsm_type = H5MF_ALLOC_TO_FS_TYPE(f, type);
-            if(!fsm_visited[fsm_type]) {
-                fsm_visited[fsm_type] = TRUE;
-
-                /* If there is no active FSM for this type, but such a FSM has
-                 * space allocated in file, open it so that we can free its file
-                 * space.
-                 */
-                if(NULL == f->shared->fs_man[fsm_type]) {
-                    if(H5F_addr_defined(f->shared->fs_addr[fsm_type])) {
-                        /* Sanity check */
-                        HDassert(fsm_opened[fsm_type] == FALSE);
-
-                        /* Start up FSM for the file memory type */
-                        if(H5MF__alloc_open(f, dxpl_id, fsm_type) < 0)
-                            HGOTO_ERROR(H5E_RESOURCE, H5E_CANTINIT, FAIL, "can't initialize file free space manager")
-                        fsm_opened[fsm_type] = TRUE;
-                    } /* end if */
+        for(pass_count = 0; pass_count <= 1; pass_count++) {
+            if(pass_count == 0)
+                alloc_size = 1;
+            else if ( H5F_PAGED_AGGR(f) )
+                alloc_size = f->shared->fs_page_size + 1;
+            else /* no need for a second pass */
+                break;
+
+            for(mem_type = H5FD_MEM_SUPER; mem_type < H5FD_MEM_NTYPES; H5_INC_ENUM(H5F_mem_t, mem_type)) {
+                H5MF_alloc_to_fs_type(f, mem_type, alloc_size, &fsm_type);
+
+                if(pass_count == 0) { /* this is the first pass */
+                    HDassert(fsm_type > H5F_MEM_PAGE_DEFAULT);
+                    HDassert(fsm_type < H5F_MEM_PAGE_LARGE_SUPER);
                 } /* end if */
+                else if(H5F_PAGED_AGGR(f)) { /* page alloc active */
+                    HDassert(fsm_type >= H5F_MEM_PAGE_LARGE_SUPER);
+                    HDassert(fsm_type < H5F_MEM_PAGE_NTYPES);
+                } /* end else-if */
+                else    /* paged allocation disabled -- should be unreachable */
+                    HDassert(FALSE);
+
+                if(!fsm_visited[fsm_type]) {
+                    fsm_visited[fsm_type] = TRUE;
+
+                    /* If there is no active FSM for this type, but such a FSM has
+                     * space allocated in file, open it so that we can free its file
+                     * space.
+                     */
+                    if(NULL == f->shared->fs_man[fsm_type]) {
+                        if(H5F_addr_defined(f->shared->fs_addr[fsm_type])) {
+                            /* Sanity check */
+                            HDassert(fsm_opened[fsm_type] == FALSE);
 
-                /* Check for an actual FSM for this type now */
-                /* (Possibly opened in previous step) */
-                if(f->shared->fs_man[fsm_type]) {
-                    /* Test to see if we need to switch rings -- do so if required */
-                    if((fsm_type == H5MF_ALLOC_TO_FS_TYPE(f, H5FD_MEM_FSPACE_HDR))
-                           || (fsm_type == H5MF_ALLOC_TO_FS_TYPE(f, H5FD_MEM_FSPACE_SINFO)))
-                        needed_ring = H5AC_RING_MDFSM;
-                    else
-                        needed_ring = H5AC_RING_RDFSM;
-                    if(needed_ring != curr_ring) {
-                        if(H5AC_set_ring(dxpl_id, needed_ring, &dxpl, &curr_ring) < 0)
-                            HGOTO_ERROR(H5E_RESOURCE, H5E_CANTSET, FAIL, "unable to set ring value")
-                        curr_ring = needed_ring;
+                             if(H5MF_open_fstype(f, dxpl_id, fsm_type) < 0)
+                                 HGOTO_ERROR(H5E_RESOURCE, H5E_CANTINIT, FAIL, "can't initialize file free space manager")
+                            fsm_opened[fsm_type] = TRUE;
+                        } /* end if */
                     } /* end if */
 
-                    /* Query free space manager info for this type */
-                    if(H5FS_stat_info(f, f->shared->fs_man[fsm_type], &fs_stat) < 0)
-                        HGOTO_ERROR(H5E_RESOURCE, H5E_CANTRELEASE, FAIL, "can't get free-space info")
+                    if(f->shared->fs_man[fsm_type]) {
+                        /* Test to see if we need to switch rings -- do so if required */
+                        if(H5MF__fsm_type_is_self_referential(f, fsm_type))
+                             needed_ring = H5AC_RING_MDFSM;
+                        else
+                             needed_ring = H5AC_RING_RDFSM;
+
+                        if(needed_ring != curr_ring) {
+                            if(H5AC_set_ring(dxpl_id, needed_ring, &dxpl, &curr_ring) < 0)
+                                HGOTO_ERROR(H5E_RESOURCE, H5E_CANTSET, FAIL, "unable to set ring value")
+                            curr_ring = needed_ring;
+                        } /* end if */
 
-                    /* Check if the free space manager has space in the file */
-                    if(H5F_addr_defined(fs_stat.addr) || H5F_addr_defined(fs_stat.sect_addr)) {
-                        /* Delete the free space manager in the file.  Will 
-                         * reallocate later if the free space manager contains
-                         * any free space.
-                         */
-                        if(H5FS_free(f, f->shared->fs_man[fsm_type], dxpl_id) < 0)
-                            HGOTO_ERROR(H5E_RESOURCE, H5E_CANTRELEASE, FAIL, "can't release free-space headers")
-                        f->shared->fs_addr[fsm_type] = HADDR_UNDEF;
+                        /* Query free space manager info for this type */
+                        if(H5FS_stat_info(f, f->shared->fs_man[fsm_type], &fs_stat) < 0)
+                            HGOTO_ERROR(H5E_RESOURCE, H5E_CANTRELEASE, FAIL, "can't get free-space info")
+
+                        /* Check if the free space manager has space in the file */
+                        if(H5F_addr_defined(fs_stat.addr) || H5F_addr_defined(fs_stat.sect_addr)) {
+                            /* Delete the free space manager in the file.  Will 
+                             * reallocate later if the free space manager contains
+                             * any free space.
+                             */
+                            if(H5FS_free(f, f->shared->fs_man[fsm_type], dxpl_id, TRUE) < 0)
+                                HGOTO_ERROR(H5E_RESOURCE, H5E_CANTRELEASE, FAIL, "can't release free-space headers")
+                            f->shared->fs_addr[fsm_type] = HADDR_UNDEF;
+                        } /* end if */
                     } /* end if */
-                } /* end if */
 
-                /* note that we are tracking opened FSM -- we will close them
-                 * at the end of the function.
-                 */
-            } /* end if */
+                    /* note that we are tracking opened FSM -- we will close them
+                     * at the end of the function.
+                     */
+                } /* end if */
+            } /* end for */
         } /* end for */
 
+
         /* c) Delete the free space manager superblock extension message
          *    if allocated.
          *
          *    Must do this since the routine that writes / creates superblock
          *    extension messages will choke if the target message is
          *    unexpectedly either absent or present.
+         *
+         *    Update: This is probably unecessary, as I gather that the 
+         *            file space manager info message is guaranteed to exist.
+         *            Leave it in for now, but consider removing it.
          */
         if(H5F_addr_defined(f->shared->sblock->ext_addr))
             if(H5F_super_ext_remove_msg(f, dxpl_id, H5O_FSINFO_ID) < 0)
@@ -1496,11 +2966,16 @@ H5MF_settle_raw_data_fsm(H5F_t *f, hid_t dxpl_id, hbool_t *fsm_settled)
          * those addresses are unknown.  This is OK -- we will write the correct
          * values to the message at free space manager shutdown.
          */
-        for(type = H5FD_MEM_SUPER; type < H5FD_MEM_NTYPES; H5_INC_ENUM(H5FD_mem_t, type))
-            fsinfo.fs_addr[type - 1] = HADDR_UNDEF;
+        for(fsm_type = H5F_MEM_PAGE_SUPER; fsm_type < H5F_MEM_PAGE_NTYPES; H5_INC_ENUM(H5F_mem_page_t, fsm_type))
+            fsinfo.fs_addr[fsm_type - 1] = HADDR_UNDEF;
         fsinfo.strategy = f->shared->fs_strategy;
+        fsinfo.persist = f->shared->fs_persist;
         fsinfo.threshold = f->shared->fs_threshold;
-        if(H5F_super_ext_write_msg(f, dxpl_id, H5O_FSINFO_ID, &fsinfo, TRUE, H5O_MSG_NO_FLAGS_SET) < 0)
+        fsinfo.page_size = f->shared->fs_page_size;
+        fsinfo.pgend_meta_thres = f->shared->pgend_meta_thres;
+        fsinfo.eoa_pre_fsm_fsalloc = HADDR_UNDEF;
+
+        if(H5F_super_ext_write_msg(f, dxpl_id, H5O_FSINFO_ID, &fsinfo, TRUE, H5O_MSG_FLAG_MARK_IF_UNKNOWN) < 0)
             HGOTO_ERROR(H5E_RESOURCE, H5E_WRITEERROR, FAIL, "error in writing fsinfo message to superblock extension")
 
 
@@ -1524,102 +2999,117 @@ H5MF_settle_raw_data_fsm(H5F_t *f, hid_t dxpl_id, hbool_t *fsm_settled)
          */
 
         /* Reinitialize fsm_visited */
-        HDmemset(fsm_visited, 0, sizeof(fsm_visited));
-
-        for(type = H5FD_MEM_SUPER; type < H5FD_MEM_NTYPES; H5_INC_ENUM(H5FD_mem_t, type)) {
-            H5FD_mem_t  fsm_type;       /* File memory type for FSM */
-
-            fsm_type = H5MF_ALLOC_TO_FS_TYPE(f, type);
-
-            /* test to see if we need to switch rings -- do so if required */
-            if((fsm_type == H5MF_ALLOC_TO_FS_TYPE(f, H5FD_MEM_FSPACE_HDR))
-                    || (fsm_type == H5MF_ALLOC_TO_FS_TYPE(f, H5FD_MEM_FSPACE_SINFO)))
-                needed_ring = H5AC_RING_MDFSM;
-            else
-                needed_ring = H5AC_RING_RDFSM;
-
-            if(needed_ring != curr_ring) {
-                if(H5AC_set_ring(dxpl_id, needed_ring, &dxpl, &curr_ring)< 0)
-                    HGOTO_ERROR(H5E_RESOURCE, H5E_CANTSET, FAIL, "unable to set ring value")
-                curr_ring = needed_ring;
-            } /* end if */
-
-            /* Since there can be a many-to-one mapping from memory types
-             * to free space managers, ensure that we don't visit any FSM
-             * more than once.
-             */
-            if(!fsm_visited[fsm_type]) {
-                fsm_visited[fsm_type] = TRUE;
-
-                if(f->shared->fs_man[fsm_type]) {
-                    /* Only allocate file space if the target free space manager 
-                     * doesn't allocate file space for free space managers.  Note 
-                     * that this is also the deciding factor as to whether a FSM 
-                     * in in the raw data FSM ring.
-                     */
-                    if((fsm_type != H5MF_ALLOC_TO_FS_TYPE(f, H5FD_MEM_FSPACE_HDR)) 
-                            && (fsm_type != H5MF_ALLOC_TO_FS_TYPE(f, H5FD_MEM_FSPACE_SINFO))) {
-                        H5FS_stat_t fs_stat;        /* Information for free-space manager */
+        for(fsm_type = H5F_MEM_PAGE_SUPER; fsm_type < H5F_MEM_PAGE_NTYPES; H5_INC_ENUM(H5F_mem_page_t, fsm_type))
+            fsm_visited[fsm_type] = FALSE;
+
+        for(pass_count = 0; pass_count <= 1; pass_count++) {
+            if(pass_count == 0)
+                alloc_size = 1;
+            else if(H5F_PAGED_AGGR(f))
+                alloc_size = f->shared->fs_page_size + 1;
+            else /* no need for a second pass */
+                break;
+
+            for(mem_type = H5FD_MEM_SUPER; mem_type < H5FD_MEM_NTYPES; H5_INC_ENUM(H5F_mem_t, mem_type)) {
+                H5MF_alloc_to_fs_type(f, mem_type, alloc_size, &fsm_type);
+
+                if(pass_count == 0) { /* this is the first pass */
+                    HDassert(fsm_type > H5F_MEM_PAGE_DEFAULT);
+                    HDassert(fsm_type < H5F_MEM_PAGE_LARGE_SUPER);
+                } /* end if */
+                else if(H5F_PAGED_AGGR(f)) { /* page alloc active */
+                    HDassert(fsm_type >= H5F_MEM_PAGE_LARGE_SUPER);
+                    HDassert(fsm_type < H5F_MEM_PAGE_NTYPES);
+                } /* end else-if */
+                else  /* paged allocation disabled -- should be unreachable */
+                    HDassert(FALSE);
 
-                        /* The current ring should be H5AC_RING_RDFSM */
-                        HDassert(curr_ring == H5AC_RING_RDFSM);
+                /* test to see if we need to switch rings -- do so if required */
+                if(H5MF__fsm_type_is_self_referential(f, fsm_type))
+                    needed_ring = H5AC_RING_MDFSM;
+                else
+                    needed_ring = H5AC_RING_RDFSM;
 
-                        /* Query free space manager info for this type */
-                        if(H5FS_stat_info(f, f->shared->fs_man[fsm_type], &fs_stat) < 0 )
-                            HGOTO_ERROR(H5E_RESOURCE, H5E_CANTGET, FAIL, "can't get free-space info")
+                if(needed_ring != curr_ring) {
+                    if(H5AC_set_ring(dxpl_id, needed_ring, &dxpl, &curr_ring)< 0)
+                        HGOTO_ERROR(H5E_RESOURCE, H5E_CANTSET, FAIL, "unable to set ring value")
+                    curr_ring = needed_ring;
+                } /* end if */
 
-                        /* If the free space manager contains section info,
-                         * allocate space for the header and sinfo (note that
-                         * space must not be allocated at present -- verify
-                         * verify this with assertions).
+                /* Since there can be a many-to-one mapping from memory types
+                 * to free space managers, ensure that we don't visit any FSM
+                 * more than once.
+                 */
+                if(!fsm_visited[fsm_type]) {
+                    fsm_visited[fsm_type] = TRUE;
+
+                    if(f->shared->fs_man[fsm_type]) {
+                        /* Only allocate file space if the target free space manager 
+                         * doesn't allocate file space for free space managers.  Note 
+                         * that this is also the deciding factor as to whether a FSM 
+                         * in in the raw data FSM ring.
                          */
-                        if(fs_stat.serial_sect_count > 0) {
-                            /* Sanity check */
-                            HDassert(!H5F_addr_defined(fs_stat.addr));
-
-                            /* Allocate FSM header */
-                            if(H5FS_alloc_hdr(f, f->shared->fs_man[fsm_type], &f->shared->fs_addr[fsm_type], dxpl_id) < 0)
-                                HGOTO_ERROR(H5E_RESOURCE, H5E_CANTALLOC, FAIL, "can't allocated free-space header")
-
-                            /* Allocate FSM section info */
-                            HDassert(!H5F_addr_defined(fs_stat.sect_addr));
-                            HDassert(fs_stat.alloc_sect_size == 0);
-                            if(H5FS_alloc_sect(f, f->shared->fs_man[fsm_type], dxpl_id) < 0 )
-                                HGOTO_ERROR(H5E_RESOURCE, H5E_CANTALLOC, FAIL, "can't allocate free-space section info")
+                        if(!H5MF__fsm_type_is_self_referential(f, fsm_type)) {
+                            /* The current ring should be H5AC_RING_RDFSM */
+                            HDassert(curr_ring == H5AC_RING_RDFSM);
+
+                            /* Query free space manager info for this type */
+                            if(H5FS_stat_info(f, f->shared->fs_man[fsm_type], &fs_stat) < 0 )
+                                HGOTO_ERROR(H5E_RESOURCE, H5E_CANTGET, FAIL, "can't get free-space info")
+
+                            /* If the free space manager contains section info,
+                             * allocate space for the header and sinfo (note that
+                             * space must not be allocated at present -- verify
+                             * verify this with assertions).
+                             */
+                            if(fs_stat.serial_sect_count > 0) {
+                                /* Sanity check */
+                                HDassert(!H5F_addr_defined(fs_stat.addr));
+
+                                /* Allocate FSM header */
+                                if(H5FS_alloc_hdr(f, f->shared->fs_man[fsm_type], &f->shared->fs_addr[fsm_type], dxpl_id) < 0)
+                                    HGOTO_ERROR(H5E_RESOURCE, H5E_CANTALLOC, FAIL, "can't allocated free-space header")
+
+                                /* Allocate FSM section info */
+                                HDassert(!H5F_addr_defined(fs_stat.sect_addr));
+                                HDassert(fs_stat.alloc_sect_size == 0);
+                                if(H5FS_alloc_sect(f, f->shared->fs_man[fsm_type], dxpl_id) < 0 )
+                                    HGOTO_ERROR(H5E_RESOURCE, H5E_CANTALLOC, FAIL, "can't allocate free-space section info")
 
 #ifndef NDEBUG
-                            /* Re-Query free space manager info for this type */
-                            if(H5FS_stat_info(f, f->shared->fs_man[fsm_type], &fs_stat) < 0)
-                                HGOTO_ERROR(H5E_RESOURCE, H5E_CANTRELEASE, FAIL, "can't get free-space info")
-
-                            HDassert(H5F_addr_defined(fs_stat.addr));
-                            HDassert(H5F_addr_defined(fs_stat.sect_addr));
-                            HDassert(fs_stat.serial_sect_count > 0);
-                            HDassert(fs_stat.alloc_sect_size > 0);
-                            HDassert(fs_stat.alloc_sect_size == fs_stat.sect_size);
+                                /* Re-Query free space manager info for this type */
+                                if(H5FS_stat_info(f, f->shared->fs_man[fsm_type], &fs_stat) < 0)
+                                    HGOTO_ERROR(H5E_RESOURCE, H5E_CANTRELEASE, FAIL, "can't get free-space info")
+
+                                HDassert(H5F_addr_defined(fs_stat.addr));
+                                HDassert(H5F_addr_defined(fs_stat.sect_addr));
+                                HDassert(fs_stat.serial_sect_count > 0);
+                                HDassert(fs_stat.alloc_sect_size > 0);
+                                HDassert(fs_stat.alloc_sect_size == fs_stat.sect_size);
 #endif /* NDEBUG */
+                            } /* end if */
+                            else {
+                                HDassert(!H5F_addr_defined(fs_stat.addr));
+                                HDassert(!H5F_addr_defined(fs_stat.sect_addr));
+                                HDassert(fs_stat.serial_sect_count == 0);
+                                HDassert(fs_stat.alloc_sect_size == 0);
+                            } /* end else */
                         } /* end if */
-                        else {
-                            HDassert(!H5F_addr_defined(fs_stat.addr));
-                            HDassert(!H5F_addr_defined(fs_stat.sect_addr));
-                            HDassert(fs_stat.serial_sect_count == 0);
-                            HDassert(fs_stat.alloc_sect_size == 0);
-                        } /* end else */
                     } /* end if */
-                } /* end if */
 
-                /* Close any opened FSMs */
-                if(fsm_opened[fsm_type]) {
-                    if(H5MF__alloc_close(f, dxpl_id, fsm_type) < 0)
-                        HGOTO_ERROR(H5E_RESOURCE, H5E_CANTINIT, FAIL, "can't close file free space manager")
-                    fsm_opened[fsm_type] = FALSE;
+                    /* Close any opened FSMs */
+                    if(fsm_opened[fsm_type]) {
+                        if(H5MF__close_fstype(f, dxpl_id, fsm_type) < 0)
+                            HGOTO_ERROR(H5E_RESOURCE, H5E_CANTINIT, FAIL, "can't close file free space manager")
+                        fsm_opened[fsm_type] = FALSE;
+                    } /* end if */
                 } /* end if */
-            } /* end if */
+            } /* end for */
         } /* end for */
 
         /* verify that all opened FSMs were closed */
-        for(type = H5FD_MEM_SUPER; type < H5FD_MEM_NTYPES; H5_INC_ENUM(H5FD_mem_t, type))
-            HDassert(!fsm_opened[type]);
+        for(fsm_type = H5F_MEM_PAGE_SUPER; fsm_type < H5F_MEM_PAGE_NTYPES; H5_INC_ENUM(H5F_mem_page_t, fsm_type))
+            HDassert(!fsm_opened[fsm_type]);
 
         /* Indicate that the FSM was settled successfully */
         *fsm_settled = TRUE;
@@ -1640,11 +3130,11 @@ done:
  *
  * Purpose: 	If the free space manager is persistent, handle any tasks 
  *		required before the metadata cache can serialize or flush 
- *		the metadata free space manager(sI) that handle file space 
+ *		the metadata free space manager(s) that handle file space 
  *		allocation for free space managers.
  *
  *		In most cases, there will be only one manager assigned 
- *		to this role.  However, since for reason or reason unknown,
+ *		to this role.  However, since for reasons unknown,
  *		free space manager headers and section info blocks are 
  *		different classes of memory, it is possible that two free 
  *		space managers will be involved.
@@ -1652,7 +3142,7 @@ done:
  *		On entry to this function, the raw data settle routine
  *		(H5MF_settle_raw_data_fsm()) should have:
  *
- *		1) Freed the accumulators.
+ *              1) Freed the aggregators.
  *
  *		2) Freed all file space allocated to the free space managers.
  *
@@ -1688,9 +3178,12 @@ done:
  *		1) Verify that the free space manager(s) involved in file
  *		   space allocation for free space managers are still floating.
  *
- *		2) Free the accumulators.
+ *              2) Free the aggregators.
  *
- *		3) Reduce the EOA to the extent possible.
+ *              3) Reduce the EOA to the extent possible, and make note
+ *		   of the resulting value.  This value will be stored 
+ *		   in the fsinfo superblock extension message and be used
+ *                 in the subsequent file open.
  *
  *		4) Re-allocate space for any free space manager(s) that:
  *
@@ -1724,6 +3217,9 @@ done:
  *		   severe time pressure at the moment, the above brute 
  *		   force solution is attractive. 
  *
+ *              5) Make note of the EOA -- used for sanity checking on 
+ *                 FSM shutdown.
+ *
  * Return:	SUCCEED/FAIL
  *
  * Programmer:  John Mainzer
@@ -1734,10 +3230,23 @@ done:
 herr_t
 H5MF_settle_meta_data_fsm(H5F_t *f, hid_t dxpl_id, hbool_t *fsm_settled)
 {
+    H5F_mem_page_t sm_fshdr_fs_type;	/* small fs hdr fsm */
+    H5F_mem_page_t sm_fssinfo_fs_type;  /* small fs sinfo fsm */
+    H5F_mem_page_t lg_fshdr_fs_type;    /* large fs hdr fsm */
+    H5F_mem_page_t lg_fssinfo_fs_type;  /* large fs sinfo fsm */
+    H5FS_t     *sm_hdr_fspace = NULL;   /* ptr to sm FSM hdr alloc FSM */
+    H5FS_t     *sm_sinfo_fspace = NULL; /* ptr to sm FSM sinfo alloc FSM */
+    H5FS_t     *lg_hdr_fspace = NULL;   /* ptr to lg FSM hdr alloc FSM */
+    H5FS_t     *lg_sinfo_fspace = NULL; /* ptr to lg FSM sinfo alloc FSM */
+    haddr_t eoa_pre_fsm_fsalloc;        /* eoa pre file space allocation */
+                                        /* for self referential FSMs */
+    haddr_t eoa_post_fsm_fsalloc;       /* eoa post file space allocation */
+                                        /* for self referential FSMs */
+    H5FS_stat_t fs_stat;                /* Information for hdr FSM */
     H5P_genplist_t *dxpl = NULL;        /* DXPL for setting ring */
     H5AC_ring_t orig_ring = H5AC_RING_INV; /* Original ring value */
     hbool_t	reset_ring = FALSE;     /* Whether we set the ring */
-    herr_t 	ret_value = SUCCEED;        /* Return value */
+    herr_t 	ret_value = SUCCEED;    /* Return value */
 
     FUNC_ENTER_NOAPI_TAG(dxpl_id, H5AC__FREESPACE_TAG, FAIL)
 
@@ -1746,29 +3255,49 @@ H5MF_settle_meta_data_fsm(H5F_t *f, hid_t dxpl_id, hbool_t *fsm_settled)
     HDassert(f->shared);
     HDassert(fsm_settled);
 
-    /* Only need to settle things if we are persisting the free space info */
-    if(f->shared->fs_strategy == H5F_FILE_SPACE_ALL_PERSIST) {
-        H5FS_t     *hdr_fspace;             /* Ptr to FSM hdr alloc FSM */
-        H5FS_t     *sinfo_fspace;           /* Ptr to FSM sinfo alloc FSM */
-        H5FS_stat_t fs_stat;		    /* Information for FSM */
-        H5FD_mem_t  hdr_fsm_alloc_type;	    /* FSM hdr alloc type */
-        H5FD_mem_t  sinfo_fsm_alloc_type;   /* FSM info alloc type */
-
-        /* Get the file memory types for the FSM header & section info */
-        hdr_fsm_alloc_type = H5MF_ALLOC_TO_FS_TYPE(f, H5FD_MEM_FSPACE_HDR);
-        sinfo_fsm_alloc_type = H5MF_ALLOC_TO_FS_TYPE(f, H5FD_MEM_FSPACE_SINFO);
-
-        /* Sanity checks */
-        HDassert(hdr_fsm_alloc_type > H5FD_MEM_NOLIST);
-        HDassert(hdr_fsm_alloc_type < H5FD_MEM_NTYPES);
-        HDassert(sinfo_fsm_alloc_type > H5FD_MEM_NOLIST);
-        HDassert(sinfo_fsm_alloc_type < H5FD_MEM_NTYPES);
-        HDassert(!H5F_addr_defined(f->shared->fs_addr[hdr_fsm_alloc_type]));
-        HDassert(!H5F_addr_defined(f->shared->fs_addr[sinfo_fsm_alloc_type]));
-
-        /* Note that in most cases, hdr_fspace will equal sinfo_fspace. */
-        hdr_fspace = f->shared->fs_man[hdr_fsm_alloc_type];
-        sinfo_fspace = f->shared->fs_man[sinfo_fsm_alloc_type];
+    /* Only need to settle things if we are persisting the free space info 
+     * and allocation/deallocation has occurred.
+     */
+    if(f->shared->fs_persist && !f->shared->first_alloc_dealloc) {
+        /* Sanity check */
+        HDassert(f->shared->lf);
+
+        /* should only be called if file is opened R/W */
+        HDassert(H5F_INTENT(f) & H5F_ACC_RDWR);
+
+        H5MF_alloc_to_fs_type(f, H5FD_MEM_FSPACE_HDR, (size_t)1, &sm_fshdr_fs_type);
+        H5MF_alloc_to_fs_type(f, H5FD_MEM_FSPACE_SINFO, (size_t)1, &sm_fssinfo_fs_type);
+
+        HDassert(sm_fshdr_fs_type > H5F_MEM_PAGE_DEFAULT);
+        HDassert(sm_fshdr_fs_type < H5F_MEM_PAGE_LARGE_SUPER);
+
+        HDassert(sm_fssinfo_fs_type > H5F_MEM_PAGE_DEFAULT);
+        HDassert(sm_fssinfo_fs_type < H5F_MEM_PAGE_LARGE_SUPER);
+
+        HDassert(!H5F_addr_defined(f->shared->fs_addr[sm_fshdr_fs_type]));
+        HDassert(!H5F_addr_defined(f->shared->fs_addr[sm_fssinfo_fs_type]));
+
+        /* Note that in most cases, sm_hdr_fspace will equal sm_sinfo_fspace. */
+        sm_hdr_fspace = f->shared->fs_man[sm_fshdr_fs_type];
+        sm_sinfo_fspace = f->shared->fs_man[sm_fssinfo_fs_type];
+
+        if(H5F_PAGED_AGGR(f)) {
+            H5MF_alloc_to_fs_type(f, H5FD_MEM_FSPACE_HDR, f->shared->fs_page_size + 1, &lg_fshdr_fs_type);
+            H5MF_alloc_to_fs_type(f, H5FD_MEM_FSPACE_SINFO, f->shared->fs_page_size + 1, &lg_fssinfo_fs_type);
+
+            HDassert(lg_fshdr_fs_type >= H5F_MEM_PAGE_LARGE_SUPER);
+            HDassert(lg_fshdr_fs_type < H5F_MEM_PAGE_NTYPES);
+
+            HDassert(lg_fssinfo_fs_type >= H5F_MEM_PAGE_LARGE_SUPER);
+            HDassert(lg_fssinfo_fs_type < H5F_MEM_PAGE_NTYPES);
+
+            HDassert(!H5F_addr_defined(f->shared->fs_addr[lg_fshdr_fs_type]));
+            HDassert(!H5F_addr_defined(f->shared->fs_addr[lg_fssinfo_fs_type]));
+
+            /* Note that in most cases, lg_hdr_fspace will equal lg_sinfo_fspace. */
+            lg_hdr_fspace = f->shared->fs_man[lg_fshdr_fs_type];
+            lg_sinfo_fspace = f->shared->fs_man[lg_fssinfo_fs_type];
+        } /* end if */
 
         /* Set the ring in the dxpl appropriately for subsequent calls */
         if(H5AC_set_ring(dxpl_id, H5AC_RING_MDFSM, &dxpl, &orig_ring) < 0)
@@ -1776,41 +3305,109 @@ H5MF_settle_meta_data_fsm(H5F_t *f, hid_t dxpl_id, hbool_t *fsm_settled)
         reset_ring = TRUE;
 
 #ifndef NDEBUG
-        /* Verify that hdr_fspace is floating if it exists */
-        if(hdr_fspace) {
+        /* Verify that sm_hdr_fspace is floating if it exists */
+        if(sm_hdr_fspace) {
             /* Query free space manager info for this type */
-            if(H5FS_stat_info(f, hdr_fspace, &fs_stat) < 0)
-                HGOTO_ERROR(H5E_RESOURCE, H5E_CANTGET, FAIL, "can't get free-space info")
+            if(H5FS_stat_info(f, sm_hdr_fspace, &fs_stat) < 0)
+                HGOTO_ERROR(H5E_RESOURCE, H5E_CANTGET, FAIL,  "can't get free-space info")
 
             HDassert(!H5F_addr_defined(fs_stat.addr));
             HDassert(!H5F_addr_defined(fs_stat.sect_addr));
             HDassert(fs_stat.alloc_sect_size == 0);
         } /* end if */
 
-        /* Verify that sinfo_fspace is floating if it exists */
-        if((sinfo_fspace) && (hdr_fspace != sinfo_fspace)) {
+        /* Verify that sm_sinfo_fspace is floating if it exists and is distinct */
+        if((sm_sinfo_fspace) && (sm_hdr_fspace != sm_sinfo_fspace)) {
             /* Query free space manager info for this type */
-            if(H5FS_stat_info(f, sinfo_fspace, &fs_stat) < 0)
+            if(H5FS_stat_info(f, sm_sinfo_fspace, &fs_stat) < 0)
                 HGOTO_ERROR(H5E_RESOURCE, H5E_CANTGET, FAIL, "can't get free-space info")
 
             HDassert(!H5F_addr_defined(fs_stat.addr));
             HDassert(!H5F_addr_defined(fs_stat.sect_addr));
             HDassert(fs_stat.alloc_sect_size == 0);
         } /* end if */
+
+        if(H5F_PAGED_AGGR(f)) {
+            /* Verify that lg_hdr_fspace is floating if it exists */
+            if(lg_hdr_fspace) {
+                /* Query free space manager info for this type */
+                if(H5FS_stat_info(f, lg_hdr_fspace, &fs_stat) < 0)
+                    HGOTO_ERROR(H5E_RESOURCE, H5E_CANTGET, FAIL, "can't get free-space info (3)")
+
+                HDassert(!H5F_addr_defined(fs_stat.addr));
+                HDassert(!H5F_addr_defined(fs_stat.sect_addr));
+                HDassert(fs_stat.alloc_sect_size == 0);
+            } /* end if */
+
+            /* Verify that lg_sinfo_fspace is floating if it 
+             * exists and is distinct 
+             */
+            if((lg_sinfo_fspace) && (lg_hdr_fspace != lg_sinfo_fspace)) {
+                /* Query free space manager info for this type */
+                if(H5FS_stat_info(f, lg_sinfo_fspace, &fs_stat) < 0)
+                    HGOTO_ERROR(H5E_RESOURCE, H5E_CANTGET, FAIL, "can't get free-space info (4)")
+
+                HDassert(!H5F_addr_defined(fs_stat.addr));
+                HDassert(!H5F_addr_defined(fs_stat.sect_addr));
+                HDassert(fs_stat.alloc_sect_size == 0);
+            } /* end if */
+        } /* end if */
 #endif /* NDEBUG */
 
         /* Free the space in the metadata aggregator.  Do this via the
          * H5MF_free_aggrs() call.  Note that the raw data aggregator must
          * have already been freed.  Sanity checks for this?
+         *
+         * Note that the aggregators will not exist if paged aggregation 
+         * is enabled -- don't attempt to free if this is the case.
          */
+        /* Vailin -- is this correct? */
         /* (for space not at EOF, it may be put into free space managers) */
-        if(H5MF_free_aggrs(f, dxpl_id) < 0)
+        if((!H5F_PAGED_AGGR(f)) && (H5MF_free_aggrs(f, dxpl_id) < 0))
             HGOTO_ERROR(H5E_RESOURCE, H5E_CANTFREE, FAIL, "can't free aggregators")
 
         /* Trying shrinking the EOA for the file */
         if(H5MF__close_shrink_eoa(f, dxpl_id) < 0)
             HGOTO_ERROR(H5E_RESOURCE, H5E_CANTSHRINK, FAIL, "can't shrink eoa")
 
+        /* At this point, the EOA should be set to a value that contains 
+         * the allocation for all user data, all non self referential FSMs,
+         * the superblock and all superblock extension messages.
+         * 
+         * Make note of the current EOA.  We will store this value in the 
+         * free space manager superblock extension message.  Since space for
+         * everything other than the self referential FSMs (and possibly the
+         * cache image) has been allocated at this point, this allows us to 
+         * to float the self referential FSMs on the first file space allocation / 
+         * deallocaiton and then set the EOA to this value before we handle
+         * the allocation / deallocation. (If a cache image exists, the 
+         * first allocation / deallocation will be the deallocation of space
+         * for the cache image).   
+         *
+         * WARNING:  This approach settling the self referential free space 
+         *           managers and allocating space for them in the file will 
+         *           not work as currently implemented with the split and 
+         *           multi file drivers, as the self referential free space 
+         *           manager header and section info can be stored in up to 
+         *           two different files -- requiring that up to two EOA's 
+         *           be stored in the the free space managers super block 
+         *           extension message.  
+         *
+         *           As of this writing, we are solving this problem by 
+         *           simply not supporting persistant FSMs with the split 
+         *           and multi file drivers.
+         *
+         *           Current plans are to do away with the multi file 
+         *           driver, so this should be a non-issue in this case.
+         *
+         *           We should be able to support the split file driver 
+         *           without a file format change.  However, the code to 
+         *           do so does not exist at present.
+         */
+         if(HADDR_UNDEF == (eoa_pre_fsm_fsalloc = H5FD_get_eoa(f->shared->lf, H5FD_MEM_DEFAULT)))
+            HGOTO_ERROR(H5E_FILE, H5E_CANTGET, FAIL, "unable to get EOA")
+
+
         /* ******************* PROBLEM: ********************
          *
          * If the file has an alignement other than 1, and if
@@ -1859,15 +3456,39 @@ H5MF_settle_meta_data_fsm(H5F_t *f, hid_t dxpl_id, hbool_t *fsm_settled)
          * This is isn't good, but due to schedule pressure, we will just drop
          * the fragment on the floor for now.
          */
-        if(hdr_fspace)
-            if(H5FS_alloc_vfd_alloc_hdr_and_section_info(f, dxpl_id, hdr_fspace,
-                    &(f->shared->fs_addr[hdr_fsm_alloc_type])) < 0)
-                HGOTO_ERROR(H5E_RESOURCE, H5E_CANTALLOC, FAIL, "can't vfd allocate hdr FSM file space")
+        if(sm_hdr_fspace)
+            if(H5FS_vfd_alloc_hdr_and_section_info_if_needed(f, dxpl_id, sm_hdr_fspace, &(f->shared->fs_addr[sm_fshdr_fs_type])) < 0)
+                HGOTO_ERROR(H5E_RESOURCE, H5E_CANTALLOC, FAIL, "can't vfd allocate sm hdr FSM file space")
+
+        if(sm_sinfo_fspace && (sm_sinfo_fspace != sm_hdr_fspace))
+            if(H5FS_vfd_alloc_hdr_and_section_info_if_needed(f, dxpl_id, sm_sinfo_fspace, &(f->shared->fs_addr[sm_fssinfo_fs_type])) < 0)
+                HGOTO_ERROR(H5E_RESOURCE, H5E_CANTALLOC, FAIL, "can't vfd allocate sm sinfo FSM file space")
+
+        if(H5F_PAGED_AGGR(f)) {
+            if(lg_hdr_fspace)
+                if(H5FS_vfd_alloc_hdr_and_section_info_if_needed(f, dxpl_id, lg_hdr_fspace, &(f->shared->fs_addr[lg_fshdr_fs_type])) < 0)
+                    HGOTO_ERROR(H5E_RESOURCE, H5E_CANTALLOC, FAIL, "can't vfd allocate lg hdr FSM file space")
+
+            if(lg_sinfo_fspace && (lg_sinfo_fspace != lg_hdr_fspace))
+                if(H5FS_vfd_alloc_hdr_and_section_info_if_needed(f, dxpl_id, lg_sinfo_fspace, &(f->shared->fs_addr[lg_fssinfo_fs_type])) < 0)
+                    HGOTO_ERROR(H5E_RESOURCE, H5E_CANTALLOC, FAIL, "can't vfd allocate lg sinfo FSM file space")
+        } /* end if */
 
-        if(sinfo_fspace && (sinfo_fspace != hdr_fspace))
-            if(H5FS_alloc_vfd_alloc_hdr_and_section_info(f, dxpl_id, sinfo_fspace,
-                    &(f->shared->fs_addr[sinfo_fsm_alloc_type])) < 0)
-                HGOTO_ERROR(H5E_RESOURCE, H5E_CANTALLOC, FAIL, "can't vfd allocate sinfo FSM file space")
+        /* Get the eoa after allocation of file space for the self referential
+         * free space managers.  Assuming no cache image, this should be the 
+         * final EOA of the file.
+         */
+        if(HADDR_UNDEF == (eoa_post_fsm_fsalloc = H5FD_get_eoa(f->shared->lf, H5FD_MEM_DEFAULT)))
+            HGOTO_ERROR(H5E_FILE, H5E_CANTGET, FAIL, "unable to get file size")
+
+        /* All free space managers should have file space allocated for them
+         * now, and should see no further allocations / deallocations.  Store
+         * the pre and post file space allocaton for self referential FSMs EOA
+         * for use when we actually write the free space manager superblock 
+         * extension message.
+         */
+        f->shared->eoa_pre_fsm_fsalloc  = eoa_pre_fsm_fsalloc;
+        f->shared->eoa_post_fsm_fsalloc = eoa_post_fsm_fsalloc;
 
         /* Indicate that the FSM was settled successfully */
         *fsm_settled = TRUE;
@@ -1878,479 +3499,410 @@ done:
         if(H5AC_reset_ring(dxpl, orig_ring) < 0)
             HDONE_ERROR(H5E_RESOURCE, H5E_CANTSET, FAIL, "unable to set property value")
 
-    FUNC_LEAVE_NOAPI(ret_value)
+    FUNC_LEAVE_NOAPI_TAG(ret_value, FAIL)
 } /* H5MF_settle_meta_data_fsm() */
 
 
 /*-------------------------------------------------------------------------
- * Function:    H5MF__close_delete
+ * Function:    H5MF__fsm_type_is_self_referential()
  *
- * Purpose:     Common code for closing and deleting freespace managers from
- *              the file.
+ * Purpose:     Return TRUE if the indicated free space manager allocates
+ *		file space for free space managers.  Return FALSE otherwise.
  *
- * Return:	SUCCEED/FAIL
+ * Return:      TRUE/FALSE
  *
- * Programmer:	Vailin Choi
- *              Jan 2016
+ * Programmer:  John Mainzer
+ *              12/6/16
  *
  *-------------------------------------------------------------------------
  */
-static herr_t
-H5MF__close_delete(H5F_t *f, hid_t dxpl_id, H5P_genplist_t **dxpl)
+hbool_t
+H5MF__fsm_type_is_self_referential(H5F_t *f, H5F_mem_page_t fsm_type)
 {
-    H5FD_mem_t type;                    /* Memory type for iteration */
-    H5AC_ring_t curr_ring = H5AC_RING_INV;      /* current ring value */
-    herr_t ret_value = SUCCEED;         /* Return value */
+    H5F_mem_page_t sm_fshdr_fsm;
+    H5F_mem_page_t sm_fssinfo_fsm;
+    H5F_mem_page_t lg_fshdr_fsm;
+    H5F_mem_page_t lg_fssinfo_fsm;
+    hbool_t result = FALSE;
 
-    FUNC_ENTER_STATIC_TAG(dxpl_id, H5AC__FREESPACE_TAG, FAIL)
-#ifdef H5MF_ALLOC_DEBUG
-HDfprintf(stderr, "%s: Entering\n", FUNC);
-#endif /* H5MF_ALLOC_DEBUG */
+    FUNC_ENTER_NOAPI_NOINIT_NOERR
 
-    /* check args */
+    /* Sanity check */
     HDassert(f);
     HDassert(f->shared);
+    HDassert(fsm_type >= H5F_MEM_PAGE_DEFAULT);
+    HDassert(fsm_type < H5F_MEM_PAGE_NTYPES);
 
-    /* Iterate over all the free space types that have managers and get each free list's space */
-    for(type = H5FD_MEM_DEFAULT; type < H5FD_MEM_NTYPES; H5_INC_ENUM(H5FD_mem_t, type)) {
-        H5AC_ring_t needed_ring;        /* Ring value needed for this iteration */
+    H5MF_alloc_to_fs_type(f, H5FD_MEM_FSPACE_HDR, (size_t)1, &sm_fshdr_fsm);
+    H5MF_alloc_to_fs_type(f, H5FD_MEM_FSPACE_SINFO, (size_t)1, &sm_fssinfo_fsm);
 
-#ifdef H5MF_ALLOC_DEBUG_MORE
-HDfprintf(stderr, "%s: Check 1.0 - f->shared->fs_man[%u] = %p, f->shared->fs_addr[%u] = %a\n", FUNC, (unsigned)type, f->shared->fs_man[type], (unsigned)type, f->shared->fs_addr[type]);
-#endif /* H5MF_ALLOC_DEBUG_MORE */
+    if(H5F_PAGED_AGGR(f)) {
+        H5MF_alloc_to_fs_type(f, H5FD_MEM_FSPACE_HDR, f->shared->fs_page_size + 1, &lg_fshdr_fsm);
+        H5MF_alloc_to_fs_type(f, H5FD_MEM_FSPACE_SINFO, f->shared->fs_page_size + 1, &lg_fssinfo_fsm);
 
-        /* test to see if we need to switch rings -- do so if required */
-        if((H5MF_ALLOC_TO_FS_TYPE(f, type) == H5MF_ALLOC_TO_FS_TYPE(f, H5FD_MEM_FSPACE_HDR))
-                || (H5MF_ALLOC_TO_FS_TYPE(f, type) == H5MF_ALLOC_TO_FS_TYPE(f, H5FD_MEM_FSPACE_SINFO)))
-            needed_ring = H5AC_RING_MDFSM;
+        result = (fsm_type == sm_fshdr_fsm) || (fsm_type == sm_fssinfo_fsm)
+                || (fsm_type == lg_fshdr_fsm) || (fsm_type == lg_fssinfo_fsm);
+    } /* end if */
+    else {
+        /* In principle, fsm_type should always be less than 
+         * H5F_MEM_PAGE_LARGE_SUPER whenever paged aggregation
+         * is not enabled.  However, since there is code that does
+         * not observe this prinicple, force the result to FALSE if
+         * fsm_type is greater than or equal to H5F_MEM_PAGE_LARGE_SUPER.
+         */
+        if(fsm_type >= H5F_MEM_PAGE_LARGE_SUPER)
+            result = FALSE;
         else
-            needed_ring = H5AC_RING_RDFSM;
-
-        if(needed_ring != curr_ring) {
-            if(H5AC_set_ring(dxpl_id, needed_ring, dxpl, &curr_ring) < 0)
-                HGOTO_ERROR(H5E_RESOURCE, H5E_CANTSET, FAIL, "unable to set ring value (4)")
-            curr_ring = needed_ring;
-        } /* end if */
-
-        /* If the free space manager for this type is open, close it */
-        if(f->shared->fs_man[type]) {
-#ifdef H5MF_ALLOC_DEBUG_MORE
-HDfprintf(stderr, "%s: Before closing free space manager\n", FUNC);
-#endif /* H5MF_ALLOC_DEBUG_MORE */
-            if(H5FS_close(f, dxpl_id, f->shared->fs_man[type]) < 0)
-                HGOTO_ERROR(H5E_RESOURCE, H5E_CANTRELEASE, FAIL, "can't release free space info")
-            f->shared->fs_man[type] = NULL;
-            f->shared->fs_state[type] = H5F_FS_STATE_CLOSED;
-        } /* end if */
-#ifdef H5MF_ALLOC_DEBUG_MORE
-HDfprintf(stderr, "%s: Check 2.0 - f->shared->fs_man[%u] = %p, f->shared->fs_addr[%u] = %a\n", FUNC, (unsigned)type, f->shared->fs_man[type], (unsigned)type, f->shared->fs_addr[type]);
-#endif /* H5MF_ALLOC_DEBUG_MORE */
-
-        /* If there is free space manager info for this type, delete it */
-        if(H5F_addr_defined(f->shared->fs_addr[type])) {
-            haddr_t tmp_fs_addr;            /* Temporary holder for free space manager address */
-
-            /* Put address into temporary variable and reset it */
-            /* (Avoids loopback in file space freeing routine) */
-            tmp_fs_addr = f->shared->fs_addr[type];
-            f->shared->fs_addr[type] = HADDR_UNDEF;
-
-            /* Shift to "deleting" state, to make certain we don't track any
-             *  file space freed as a result of deleting the free space manager.
-             */
-            f->shared->fs_state[type] = H5F_FS_STATE_DELETING;
-
-#ifdef H5MF_ALLOC_DEBUG_MORE
-HDfprintf(stderr, "%s: Before deleting free space manager\n", FUNC);
-#endif /* H5MF_ALLOC_DEBUG_MORE */
-
-            /* Delete free space manager for this type */
-            if(H5FS_delete(f, dxpl_id, tmp_fs_addr) < 0)
-                HGOTO_ERROR(H5E_RESOURCE, H5E_CANTFREE, FAIL, "can't delete free space manager")
-
-            /* Shift [back] to closed state */
-            HDassert(f->shared->fs_state[type] == H5F_FS_STATE_DELETING);
-            f->shared->fs_state[type] = H5F_FS_STATE_CLOSED;
-
-            /* Sanity check that the free space manager for this type wasn't started up again */
-            HDassert(!H5F_addr_defined(f->shared->fs_addr[type]));
-        } /* end if */
-    } /* end for */
+            result = (fsm_type == sm_fshdr_fsm) || (fsm_type == sm_fssinfo_fsm);
+    } /* end else */
 
-done:
-#ifdef H5MF_ALLOC_DEBUG
-HDfprintf(stderr, "%s: Leaving\n", FUNC);
-#endif /* H5MF_ALLOC_DEBUG */
-    FUNC_LEAVE_NOAPI_TAG(ret_value, FAIL)
-} /* H5MF__close_delete() */
+    FUNC_LEAVE_NOAPI(result)
+} /* H5MF__fsm_type_is_self_referential() */
 
 
 /*-------------------------------------------------------------------------
- * Function:    H5MF_try_close
+ * Function:    H5MF__fsm_is_self_referential()
  *
- * Purpose:     This is called by H5Fformat_convert() to close and delete
- *		free-space managers when downgrading persistent free-space
- *		to non-persistent.
+ * Purpose:     Return TRUE if the indicated free space manager allocates
+ *		file space for free space managers.  Return FALSE otherwise.
  *
- * Return:	SUCCEED/FAIL
+ * Return:      TRUE/FALSE
  *
- * Programmer:	Vailin Choi
- *              Jan 2016
+ * Programmer:  John Mainzer
+ *              12/6/16
  *
  *-------------------------------------------------------------------------
  */
-herr_t
-H5MF_try_close(H5F_t *f, hid_t dxpl_id)
+static hbool_t
+H5MF__fsm_is_self_referential(H5F_t *f, H5FS_t *fspace)
 {
-    H5P_genplist_t *dxpl = NULL;        /* DXPL for setting ring */
-    H5AC_ring_t orig_ring = H5AC_RING_INV;      /* Original ring value */
-    hbool_t reset_ring = FALSE;         /* Whether the ring was set */
-    herr_t ret_value = SUCCEED;         /* Return value */
+    H5F_mem_page_t sm_fshdr_fsm;
+    H5F_mem_page_t sm_fssinfo_fsm;
+    hbool_t result = FALSE;
 
-    FUNC_ENTER_NOAPI(FAIL)
-#ifdef H5MF_ALLOC_DEBUG
-HDfprintf(stderr, "%s: Entering\n", FUNC);
-#endif /* H5MF_ALLOC_DEBUG */
+    FUNC_ENTER_STATIC_NOERR
 
-    /* check args */
+    /* Sanity check */
     HDassert(f);
+    HDassert(f->shared);
+    HDassert(fspace);
 
-    /* Set the ring type in the DXPL */
-    if(H5AC_set_ring(dxpl_id, H5AC_RING_RDFSM, &dxpl, &orig_ring) < 0)
-        HGOTO_ERROR(H5E_RESOURCE, H5E_CANTSET, FAIL, "unable to set ring value")
-    reset_ring = TRUE;
+    H5MF_alloc_to_fs_type(f, H5FD_MEM_FSPACE_HDR, (size_t)1, &sm_fshdr_fsm);
+    H5MF_alloc_to_fs_type(f, H5FD_MEM_FSPACE_SINFO, (size_t)1, &sm_fssinfo_fsm);
 
-    /* Close and delete freespace managers from the file */
-    if(H5MF__close_delete(f, dxpl_id, &dxpl) < 0)
-        HGOTO_ERROR(H5E_RESOURCE, H5E_CANTSET, FAIL, "unable to close delete free-space managers")
+    if(H5F_PAGED_AGGR(f)) {
+        H5F_mem_page_t lg_fshdr_fsm;
+        H5F_mem_page_t lg_fssinfo_fsm;
 
-done:
-    /* Reset the ring in the DXPL */
-    if(reset_ring)
-        if(H5AC_reset_ring(dxpl, orig_ring) < 0)
-            HDONE_ERROR(H5E_RESOURCE, H5E_CANTSET, FAIL, "unable to set property value")
+        H5MF_alloc_to_fs_type(f, H5FD_MEM_FSPACE_HDR, f->shared->fs_page_size + 1, &lg_fshdr_fsm);
+        H5MF_alloc_to_fs_type(f, H5FD_MEM_FSPACE_SINFO, f->shared->fs_page_size + 1, &lg_fssinfo_fsm);
 
-#ifdef H5MF_ALLOC_DEBUG
-HDfprintf(stderr, "%s: Leaving\n", FUNC);
-#endif /* H5MF_ALLOC_DEBUG */
-    FUNC_LEAVE_NOAPI(ret_value)
-} /* H5MF_try_close() */
+        result = (fspace == f->shared->fs_man[sm_fshdr_fsm]) ||
+                   (fspace == f->shared->fs_man[sm_fssinfo_fsm]) ||
+                   (fspace == f->shared->fs_man[lg_fshdr_fsm]) ||
+                   (fspace == f->shared->fs_man[lg_fssinfo_fsm]);
+    } /* end if */
+    else
+        result = (fspace == f->shared->fs_man[sm_fshdr_fsm]) ||
+                   (fspace == f->shared->fs_man[sm_fssinfo_fsm]);
+
+    FUNC_LEAVE_NOAPI(result)
+} /* H5MF__fsm_is_self_referential() */
 
 
 /*-------------------------------------------------------------------------
- * Function:    H5MF_close
- *
- * Purpose:     Close the free space tracker(s) for a file
+ * Function:    H5MF_tidy_self_referential_fsm_hack
+ *
+ * Purpose:     As discussed in the comments of the settle routines above,
+ *		the existence of self referential free space managers
+ *		as currently implemented creates the possibility of 
+ *		infinite loops at file close.
+ *
+ *		As a hack to avoid this, we have added code to settle
+ *		self referential free space managers, and then allocate 
+ *		space for them directly from the file driver.
+ *
+ *		To avoid dropping ever increasing amounts of file space 
+ *              on the floor with each subsequent file close/open cycle,
+ *              we need to clean this up on file open.  To avoid this,
+ *              this function is called on the first file space allocation
+ *              or deallocation after file open to float the self referential
+ *              free space managers and reduce the EOA to the value it 
+ *              had before the direct allocation of space for the self 
+ *              referential free space managers.
+ *
+ *              The function proceeds as follows:
+ *
+ *              1) Verify that f->shared->first_alloc_dealloc is TRUE, 
+ *                 and then set it to FALSE.
+ *
+ *              2) Get the current EOA.  Verify that it is greater than
+ *                 or equal to f->shared->eoa_pre_fsm_fsalloc.  If the 
+ *                 current eoa is equal to f->shared->eoa_pre_fsm_fsalloc,
+ *                 no self referential FSMs were stored, and we are done.
+ *
+ *                 NOTE:  This will have to be reworked somewhat for 
+ *                 cache image.
+ *
+ *              3) Load the self referential FSMs.  In passing verify that
+ *                 the lowest address of a FSM header is equal to 
+ *                 f->shared->eoa_pre_fsm_fsalloc.'
+ *
+ *                 Note that we don't have to use any special I/O for 
+ *                 this -- we can use the regular I/O methods even if 
+ *                 paged aggregation and page buffering is enabled.
+ *
+ *              4) Float the FSMs. Ensure that the file space is NOT
+ *                 released.
+ *
+ *              5) Set EOA equal to f->shared->eoa_pre_fsm_fsalloc, 
+ *                 and then set f->shared->eoa_pre_fsm_fsalloc to 
+ *                 HADDR_UNDEF.
+ *
+ *		   If page buffering, verify that the new EOA is 
+ *                 on a page boundary, and expunge any pages in the 
+ *                 page buffer after the new EOA.
+ *
+ *              Note that this function is also called from test code
+ *              when it is necessary to startup a self referential 
+ *              free space manager prior to the first file space 
+ *              allocation / deallocation.  Failure to do so will 
+ *              result in assertion failures in this function on
+ *              the first file space allocation / deallocation.
+ *                 
+ * Return:      SUCCEED/FAIL
  *
- * Return:	SUCCEED/FAIL
- *
- * Programmer:  Quincey Koziol
- *              Tuesday, January 22, 2008
+ * Programmer:  John Mainzer
+ *              12/11/16
  *
- * Modifications:
- *      Vailin Choi; July 2012
- *      As the default free-list mapping is changed to H5FD_FLMAP_DICHOTOMY,
- *      modifications are needed to shrink EOA if the last section of each free-space manager
- *      and the remaining space in the two aggregators are at EOA.
-
  *-------------------------------------------------------------------------
  */
 herr_t
-H5MF_close(H5F_t *f, hid_t dxpl_id)
+H5MF_tidy_self_referential_fsm_hack(H5F_t *f, hid_t dxpl_id)
 {
+    haddr_t eoa;                        /* EOA of file */
+    hsize_t tail_size = 0;              /* Size of chunk to free */
     H5P_genplist_t *dxpl = NULL;        /* DXPL for setting ring */
-    H5AC_ring_t curr_ring;              /* Current ring value */
-    H5AC_ring_t orig_ring = H5AC_RING_INV;      /* Original ring value */
-    H5FD_mem_t type;                    /* Memory type for iteration */
+    H5AC_ring_t orig_ring = H5AC_RING_INV; /* Original ring value */
+    haddr_t first_srfsm_hdr = HADDR_UNDEF; /* Addr of first self referential */
+                                           /* fsm header in file             */
+    H5FS_stat_t fs_stat;                /* Information for hdr FSM */
+    H5F_mem_page_t sm_fshdr_fs_type;    /* Small fs hdr fsm */
+    H5F_mem_page_t sm_fssinfo_fs_type;  /* Small fs sinfo fsm */
+    H5F_mem_page_t lg_fshdr_fs_type;    /* Large fs hdr fsm */
+    H5F_mem_page_t lg_fssinfo_fs_type;  /* Large fs sinfo fsm */
     hbool_t reset_ring = FALSE;         /* Whether the ring was set */
     herr_t ret_value = SUCCEED;         /* Return value */
 
     FUNC_ENTER_NOAPI_TAG(dxpl_id, H5AC__FREESPACE_TAG, FAIL)
-#ifdef H5MF_ALLOC_DEBUG
-HDfprintf(stderr, "%s: Entering\n", FUNC);
-#endif /* H5MF_ALLOC_DEBUG */
 
     /* check args */
     HDassert(f);
     HDassert(f->shared);
-    HDassert(f->shared->lf);
-    HDassert(f->shared->sblock);
+    HDassert(f->shared->fs_persist);
+    HDassert(f->shared->first_alloc_dealloc);
 
-    /* Set the ring type in the DXPL.  In most cases, we will
-     * need H5AC_RING_RDFSM, so initialy set the ring in
-     * the DXPL to that value.  We will alter this later if 
-     * needed.
+    /* Set the ring type in the DXPL.  Since we are only dealing with 
+     * self referential FSMs, we will only need H5AC_RING_MDFSM.
      */
-    if(H5AC_set_ring(dxpl_id, H5AC_RING_RDFSM, &dxpl, &orig_ring) < 0)
+    if(H5AC_set_ring(dxpl_id, H5AC_RING_MDFSM, &dxpl, &orig_ring) < 0)
         HGOTO_ERROR(H5E_RESOURCE, H5E_CANTSET, FAIL, "unable to set ring value")
     reset_ring = TRUE;
-    curr_ring = H5AC_RING_RDFSM;
 
-    /* Free the space in aggregators */
-    /* (for space not at EOF, it may be put into free space managers) */
-    if(H5MF_free_aggrs(f, dxpl_id) < 0)
-        HGOTO_ERROR(H5E_FILE, H5E_CANTFREE, FAIL, "can't free aggregators")
+    /* 1) Verify that f->shared->first_alloc_dealloc is TRUE, 
+     *    and then set it to FALSE.  
+     */
+    HDassert(f->shared->first_alloc_dealloc);
+    f->shared->first_alloc_dealloc = FALSE;
 
-    /* Trying shrinking the EOA for the file */
-    if(H5MF__close_shrink_eoa(f, dxpl_id) < 0)
-        HGOTO_ERROR(H5E_RESOURCE, H5E_CANTSHRINK, FAIL, "can't shrink eoa")
 
-    /* Making free-space managers persistent for superblock version >= 2 */
-    if(f->shared->sblock->super_vers >= HDF5_SUPERBLOCK_VERSION_2
-            && f->shared->fs_strategy == H5F_FILE_SPACE_ALL_PERSIST) {
-        H5O_fsinfo_t fsinfo;		/* Free space manager info message */
+    /* 2) Get the current EOA.  Verify that it is greater than
+     *    or equal to f->shared->eoa_pre_fsm_fsalloc.  If the 
+     *    current eoa is equal to f->shared->eoa_pre_fsm_fsalloc,
+     *    no self referential FSMs were stored, and we are done.
+     *
+     *    NOTE:  This will have to be reworked somewhat for 
+     *           cache image.
+     */
+    if(HADDR_UNDEF == (eoa = H5FD_get_eoa(f->shared->lf, H5FD_MEM_DEFAULT)))
+        HGOTO_ERROR(H5E_FILE, H5E_CANTGET, FAIL, "unable to get EOA")
+    HDassert(H5F_addr_le(f->shared->eoa_pre_fsm_fsalloc, eoa));
 
-        /* Superblock extension and free space manager message should 
-         * exist at this point -- verify at least the former.
-         */
-        HDassert(H5F_addr_defined(f->shared->sblock->ext_addr));
+    if(H5F_addr_eq(f->shared->eoa_pre_fsm_fsalloc, eoa))
+        HGOTO_DONE(SUCCEED)
 
-        /* Note that unlike the previous version of this code, we do not 
-         * delete free space managers that have no section to store.
-         *
-         * Can't do this, as that would involve freeing file space, which would 
-         * dirty the free space manager in question. 
-         * 
-         * Fortunately, the code doesn't seem to care about this.
-         */
 
-        /* Gather data for the free space manager superblock extension message.
-         * 
-         * In passing, verify that all the free space managers are closed.
-         */
-        for(type = H5FD_MEM_SUPER; type < H5FD_MEM_NTYPES; H5_INC_ENUM(H5FD_mem_t, type))
-            fsinfo.fs_addr[type - 1] = f->shared->fs_addr[type];
-	fsinfo.strategy = f->shared->fs_strategy;
-	fsinfo.threshold = f->shared->fs_threshold;
+    /* 3) Load the self referential FSMs.  In passing verify that
+     *    the lowest address of a FSM header is equal to 
+     *    f->shared->eoa_pre_fsm_fsalloc.'
+     *
+     *    Note that we don't have to use any special I/O for 
+     *    this -- we can use the regular I/O methods even if 
+     *    paged aggregation and page buffering is enabled.
+     */
+    H5MF_alloc_to_fs_type(f, H5FD_MEM_FSPACE_HDR, (size_t)1, &sm_fshdr_fs_type);
+    H5MF_alloc_to_fs_type(f, H5FD_MEM_FSPACE_SINFO, (size_t)1, &sm_fssinfo_fs_type);
+    HDassert(sm_fshdr_fs_type > H5F_MEM_PAGE_DEFAULT);
+    HDassert(sm_fshdr_fs_type < H5F_MEM_PAGE_LARGE_SUPER);
 
-        /* Write the free space manager message -- message must already exist */
-        if(H5F_super_ext_write_msg(f, dxpl_id, H5O_FSINFO_ID, &fsinfo, FALSE, H5O_MSG_NO_FLAGS_SET) < 0)
-            HGOTO_ERROR(H5E_RESOURCE, H5E_WRITEERROR, FAIL, "error in writing message to superblock extension")
+    HDassert(sm_fssinfo_fs_type > H5F_MEM_PAGE_DEFAULT);
+    HDassert(sm_fssinfo_fs_type < H5F_MEM_PAGE_LARGE_SUPER);
 
-	/* Final close of free-space managers */
-	for(type = H5FD_MEM_SUPER; type < H5FD_MEM_NTYPES; H5_INC_ENUM(H5FD_mem_t, type)) {
-	    if(f->shared->fs_man[type]) {
-                H5AC_ring_t needed_ring;    /* Ring value needed for this iteration */
+    HDassert(NULL == f->shared->fs_man[sm_fshdr_fs_type]);
+    HDassert(NULL == f->shared->fs_man[sm_fssinfo_fs_type]);
 
-                /* test to see if we need to switch rings -- do so if required */
-                if((H5MF_ALLOC_TO_FS_TYPE(f, type) == H5MF_ALLOC_TO_FS_TYPE(f, H5FD_MEM_FSPACE_HDR))
-                        || (H5MF_ALLOC_TO_FS_TYPE(f, type) == H5MF_ALLOC_TO_FS_TYPE(f, H5FD_MEM_FSPACE_SINFO)))
-                    needed_ring = H5AC_RING_MDFSM;
-                else
-                    needed_ring = H5AC_RING_RDFSM;
+    if(H5F_addr_defined(f->shared->fs_addr[sm_fshdr_fs_type])) {
+        first_srfsm_hdr = f->shared->fs_addr[sm_fshdr_fs_type];
 
-                if(needed_ring != curr_ring) {
-                    if(H5AC_set_ring(dxpl_id, needed_ring, &dxpl, &curr_ring) < 0)
-                        HGOTO_ERROR(H5E_RESOURCE, H5E_CANTSET, FAIL, "unable to set ring value (3)")
-                    curr_ring = needed_ring;
-                } /* end if */
+        /* open the FSM */
+        if(H5MF_open_fstype(f, dxpl_id, sm_fshdr_fs_type) < 0)
+             HGOTO_ERROR(H5E_RESOURCE, H5E_CANTINIT, FAIL,  "can't initialize file free space manager")
 
-                HDassert(f->shared->fs_state[type] == H5F_FS_STATE_OPEN);
-		if(H5FS_close(f, dxpl_id, f->shared->fs_man[type]) < 0)
-		    HGOTO_ERROR(H5E_RESOURCE, H5E_CANTRELEASE, FAIL, "can't close free space manager")
-		f->shared->fs_man[type] = NULL;
-		f->shared->fs_state[type] = H5F_FS_STATE_CLOSED;
-	    } /* end if */
-	    f->shared->fs_addr[type] = HADDR_UNDEF;
-	} /* end for */
+        HDassert(f->shared->fs_man[sm_fshdr_fs_type]);
+    } /* end if */
 
-        /* Verify that we haven't dirtied any metadata cache entries 
-         * from the metadata free space manager ring out.
-         */
-        HDassert(H5AC_cache_is_clean(f, H5AC_RING_MDFSM));
+    if((sm_fshdr_fs_type != sm_fssinfo_fs_type) &&
+            (H5F_addr_defined(f->shared->fs_addr[sm_fssinfo_fs_type]))) {
 
-        /* Verify that the aggregators are still shutdown. */
-        HDassert(f->shared->sdata_aggr.tot_size == 0);
-        HDassert(f->shared->sdata_aggr.addr == 0);
-        HDassert(f->shared->sdata_aggr.size == 0);
-        HDassert(f->shared->meta_aggr.tot_size == 0);
-        HDassert(f->shared->meta_aggr.addr == 0);
-        HDassert(f->shared->meta_aggr.size == 0);
-    } /* end if */
-    else {  /* super_vers can be 0, 1, 2 */
-        /* Close and delete freespace managers from the file */
-        if(H5MF__close_delete(f, dxpl_id, &dxpl) < 0)
-            HGOTO_ERROR(H5E_RESOURCE, H5E_CANTINIT, FAIL, "can't initialize file free space")
+        if(!H5F_addr_defined(first_srfsm_hdr) ||
+                (H5F_addr_defined(first_srfsm_hdr) &&
+                    H5F_addr_lt(f->shared->fs_addr[sm_fssinfo_fs_type], first_srfsm_hdr)))
+            first_srfsm_hdr = f->shared->fs_addr[sm_fssinfo_fs_type];
 
-          /* moved code that was for both the persistant and non persistant free
-           * space managers to the non-persistant case.  In the persistant
-           * case, the EOA should already be as shrunked as it can be, and the 
-           * aggregators should alread be shut down.
-           */
+        HDassert(NULL == f->shared->fs_man[sm_fssinfo_fs_type]);
 
-        /* Free the space in aggregators (again) */
-        /* (in case any free space information re-started them) */
-        if(H5MF_free_aggrs(f, dxpl_id) < 0)
-            HGOTO_ERROR(H5E_FILE, H5E_CANTFREE, FAIL, "can't free aggregators")
+        /* open the FSM */
+        if(H5MF_open_fstype(f, dxpl_id, sm_fssinfo_fs_type) < 0)
+             HGOTO_ERROR(H5E_RESOURCE, H5E_CANTINIT, FAIL, "can't initialize file free space manager")
 
-        /* Trying shrinking the EOA for the file */
-        /* (in case any free space is now at the EOA) */
-        if(H5MF__close_shrink_eoa(f, dxpl_id) < 0)
-            HGOTO_ERROR(H5E_RESOURCE, H5E_CANTSHRINK, FAIL, "can't shrink eoa")
-    } /* end else */
+        HDassert(f->shared->fs_man[sm_fssinfo_fs_type]);
+    } /* end if */
 
-done:
-    /* Reset the ring in the DXPL */
-    if(reset_ring)
-        if(H5AC_reset_ring(dxpl, orig_ring) < 0)
-            HDONE_ERROR(H5E_RESOURCE, H5E_CANTSET, FAIL, "unable to set property value")
+    if(H5F_PAGED_AGGR(f)) {
+        H5MF_alloc_to_fs_type(f, H5FD_MEM_FSPACE_HDR, f->shared->fs_page_size + 1, &lg_fshdr_fs_type);
+        H5MF_alloc_to_fs_type(f, H5FD_MEM_FSPACE_SINFO, f->shared->fs_page_size + 1, &lg_fssinfo_fs_type);
 
-#ifdef H5MF_ALLOC_DEBUG
-HDfprintf(stderr, "%s: Leaving\n", FUNC);
-#endif /* H5MF_ALLOC_DEBUG */
-    FUNC_LEAVE_NOAPI_TAG(ret_value, FAIL)
-} /* end H5MF_close() */
+        HDassert(lg_fshdr_fs_type >= H5F_MEM_PAGE_LARGE_SUPER);
+        HDassert(lg_fshdr_fs_type < H5F_MEM_PAGE_NTYPES);
 
-
-/*-------------------------------------------------------------------------
- * Function:    H5MF_sects_cb()
- *
- * Purpose:	Iterator callback for each free-space section
- *		Retrieve address and size into user data
- *
- * Return:	Always succeed
- *
- * Programmer:  Vailin Choi
- *	        July 1st, 2009
- *
- *-------------------------------------------------------------------------
- */
-static herr_t
-H5MF_sects_cb(H5FS_section_info_t *_sect, void *_udata)
-{
-    H5MF_free_section_t *sect = (H5MF_free_section_t *)_sect;
-    H5MF_sect_iter_ud_t *udata = (H5MF_sect_iter_ud_t *)_udata;
+        HDassert(lg_fssinfo_fs_type >= H5F_MEM_PAGE_LARGE_SUPER);
+        HDassert(lg_fssinfo_fs_type < H5F_MEM_PAGE_NTYPES);
 
-    FUNC_ENTER_NOAPI_NOINIT_NOERR
+        HDassert(NULL == f->shared->fs_man[lg_fshdr_fs_type]);
+        HDassert(NULL == f->shared->fs_man[lg_fssinfo_fs_type]);
 
-    if(udata->sect_idx < udata->sect_count) {
-        udata->sects[udata->sect_idx].addr = sect->sect_info.addr;
-        udata->sects[udata->sect_idx].size  = sect->sect_info.size;
-        udata->sect_idx++;
-    } /* end if */
+        if(H5F_addr_defined(f->shared->fs_addr[lg_fshdr_fs_type])) {
+            if(!H5F_addr_defined(first_srfsm_hdr) ||
+                    (H5F_addr_defined(first_srfsm_hdr) &&
+                        H5F_addr_lt(f->shared->fs_addr[lg_fshdr_fs_type], first_srfsm_hdr)))
+                first_srfsm_hdr = f->shared->fs_addr[lg_fshdr_fs_type];
 
-    FUNC_LEAVE_NOAPI(SUCCEED)
-} /* H5MF_sects_cb() */
+            HDassert(NULL == f->shared->fs_man[lg_fshdr_fs_type]);
 
-
-/*-------------------------------------------------------------------------
- * Function:    H5MF_get_free_sections()
- *
- * Purpose: 	To iterate over one or all free-space managers for:
- *			# of sections
- *			section info as defined in H5F_sect_info_t
- *
- * Return:	SUCCEED/FAIL
- *
- * Programmer:  Vailin Choi
- *	        July 1st, 2009
- *
- *-------------------------------------------------------------------------
- */
-ssize_t
-H5MF_get_free_sections(H5F_t *f, hid_t dxpl_id, H5FD_mem_t type, size_t nsects, H5F_sect_info_t *sect_info)
-{
-    size_t 	total_sects = 0;	/* total number of sections */
-    H5MF_sect_iter_ud_t sect_udata;     /* User data for callback */
-    H5P_genplist_t *dxpl = NULL;        /* DXPL for setting ring */
-    H5AC_ring_t curr_ring;              /* Current ring value */
-    H5AC_ring_t needed_ring;            /* Ring value needed for this iteration */
-    H5AC_ring_t orig_ring = H5AC_RING_INV;      /* Original ring value */
-    H5FD_mem_t	start_type, end_type;   /* Memory types to iterate over */
-    H5FD_mem_t 	ty;     		/* Memory type for iteration */
-    hbool_t reset_ring = FALSE;         /* Whether the ring was set */
-    ssize_t 	ret_value = -1;         /* Return value */
+            /* open the FSM */
+            if(H5MF_open_fstype(f, dxpl_id, lg_fshdr_fs_type) < 0)
+                 HGOTO_ERROR(H5E_RESOURCE, H5E_CANTINIT, FAIL, "can't initialize file free space manager")
+            HDassert(f->shared->fs_man[lg_fshdr_fs_type]);
+        } /* end if */
 
-    FUNC_ENTER_NOAPI_TAG(dxpl_id, H5AC__FREESPACE_TAG, FAIL)
+        if(lg_fshdr_fs_type != lg_fssinfo_fs_type && H5F_addr_defined(f->shared->fs_addr[lg_fssinfo_fs_type])) {
+            if(!H5F_addr_defined(first_srfsm_hdr) ||
+                    (H5F_addr_defined(first_srfsm_hdr) &&
+                        H5F_addr_lt(f->shared->fs_addr[lg_fssinfo_fs_type], first_srfsm_hdr)))
+                first_srfsm_hdr = f->shared->fs_addr[lg_fssinfo_fs_type];
 
-    /* check args */
-    HDassert(f);
-    HDassert(f->shared);
-    HDassert(f->shared->lf);
+            HDassert(NULL == f->shared->fs_man[lg_fssinfo_fs_type]);
 
-    /* Determine start/end points for loop */
-    if(type == H5FD_MEM_DEFAULT) {
-	start_type = H5FD_MEM_SUPER;
-	end_type = H5FD_MEM_NTYPES;
+            /* open the FSM */
+            if(H5MF_open_fstype(f, dxpl_id, lg_fssinfo_fs_type) < 0)
+                 HGOTO_ERROR(H5E_RESOURCE, H5E_CANTINIT, FAIL, "can't initialize file free space manager")
+            HDassert(f->shared->fs_man[lg_fssinfo_fs_type]);
+        } /* end if */
+    } /* end if */
+    HDassert(H5F_addr_eq(first_srfsm_hdr, f->shared->eoa_pre_fsm_fsalloc));
+ 
+    /* 4) Float the FSMs. Ensure that the file space is NOT released. */
+    if(f->shared->fs_man[sm_fshdr_fs_type]) {
+        /* Sanity check: Query free space manager info for this type */
+        if(H5FS_stat_info(f, f->shared->fs_man[sm_fshdr_fs_type], &fs_stat) < 0)
+            HGOTO_ERROR(H5E_RESOURCE, H5E_CANTRELEASE, FAIL, "can't get free-space info")
+
+        HDassert(H5F_addr_defined(fs_stat.addr));
+        HDassert(H5F_addr_defined(fs_stat.sect_addr));
+        if(H5FS_free(f, f->shared->fs_man[sm_fshdr_fs_type], dxpl_id, FALSE) < 0)
+            HGOTO_ERROR(H5E_RESOURCE, H5E_CANTRELEASE, FAIL, "can't release free-space headers")
+        f->shared->fs_addr[sm_fshdr_fs_type] = HADDR_UNDEF;
     } /* end if */
-    else {
-	start_type = end_type = type;
-	H5_INC_ENUM(H5FD_mem_t, end_type);
-    } /* end else */
-
-    /* Set up user data for section iteration */
-    sect_udata.sects = sect_info;
-    sect_udata.sect_count = nsects;
-    sect_udata.sect_idx = 0;
 
-    /* Set the ring type in the DXPL.  Note that if we are 
-     * scanning a number of different free space managers, 
-     * we may have to change the ring
-     */
-    if((H5MF_ALLOC_TO_FS_TYPE(f, start_type) == H5MF_ALLOC_TO_FS_TYPE(f, H5FD_MEM_FSPACE_HDR))
-            || (H5MF_ALLOC_TO_FS_TYPE(f, start_type) == H5MF_ALLOC_TO_FS_TYPE(f, H5FD_MEM_FSPACE_SINFO)))
-        needed_ring = H5AC_RING_MDFSM;
-    else
-        needed_ring = H5AC_RING_RDFSM;
-    curr_ring = needed_ring;
-    if(H5AC_set_ring(dxpl_id, needed_ring, &dxpl, &orig_ring) < 0)
-        HGOTO_ERROR(H5E_RESOURCE, H5E_CANTSET, FAIL, "unable to set ring value")
-    reset_ring = TRUE;
+    if(sm_fshdr_fs_type != sm_fssinfo_fs_type && f->shared->fs_man[sm_fssinfo_fs_type]) {
+        /* Sanity check: Query free space manager info for this type */
+        if(H5FS_stat_info(f, f->shared->fs_man[sm_fssinfo_fs_type], &fs_stat) < 0)
+            HGOTO_ERROR(H5E_RESOURCE, H5E_CANTRELEASE, FAIL, "can't get free-space info")
 
-    /* Iterate over memory types, retrieving the number of sections of each type */
-    for(ty = start_type; ty < end_type; H5_INC_ENUM(H5FD_mem_t, ty)) {
-	hbool_t fs_started = FALSE;
+        HDassert(H5F_addr_defined(fs_stat.addr));
+        HDassert(H5F_addr_defined(fs_stat.sect_addr));
+        if(H5FS_free(f, f->shared->fs_man[sm_fssinfo_fs_type], dxpl_id, FALSE) < 0)
+            HGOTO_ERROR(H5E_RESOURCE, H5E_CANTRELEASE, FAIL, "can't release free-space headers")
+        f->shared->fs_addr[sm_fssinfo_fs_type] = HADDR_UNDEF;
+    } /* end if */
 
-        /* test to see if we need to switch rings -- do so if required */
-        if((H5MF_ALLOC_TO_FS_TYPE(f, ty) == H5MF_ALLOC_TO_FS_TYPE(f, H5FD_MEM_FSPACE_HDR))
-                || (H5MF_ALLOC_TO_FS_TYPE(f, ty) == H5MF_ALLOC_TO_FS_TYPE(f, H5FD_MEM_FSPACE_SINFO)))
-            needed_ring = H5AC_RING_MDFSM;
-        else
-            needed_ring = H5AC_RING_RDFSM;
+    if(H5F_PAGED_AGGR(f)) {
+        if(f->shared->fs_man[lg_fshdr_fs_type]) {
+            /* Sanity check: Query free space manager info for this type */
+            if(H5FS_stat_info(f, f->shared->fs_man[lg_fshdr_fs_type], &fs_stat) < 0)
+                HGOTO_ERROR(H5E_RESOURCE, H5E_CANTGET, FAIL, "can't get free-space info")
 
-        if(needed_ring != curr_ring) {
-            if(H5AC_set_ring(dxpl_id, needed_ring, &dxpl, &curr_ring) < 0)
-                HGOTO_ERROR(H5E_RESOURCE, H5E_CANTSET, FAIL, "unable to set ring value (2)")
-            curr_ring = needed_ring;
+            HDassert(H5F_addr_defined(fs_stat.addr));
+            HDassert(H5F_addr_defined(fs_stat.sect_addr));
+            if(H5FS_free(f, f->shared->fs_man[lg_fshdr_fs_type], dxpl_id, FALSE) < 0)
+                HGOTO_ERROR(H5E_RESOURCE, H5E_CANTRELEASE, FAIL, "can't float free-space headers")
+            f->shared->fs_addr[lg_fshdr_fs_type] = HADDR_UNDEF;
         } /* end if */
 
-	/* Open free space manager of this type, if it isn't already */
-        if(!f->shared->fs_man[ty] && H5F_addr_defined(f->shared->fs_addr[ty])) {
-	    if(H5MF__alloc_open(f, dxpl_id, ty) < 0)
-		HGOTO_ERROR(H5E_RESOURCE, H5E_CANTOPENOBJ, FAIL, "can't initialize file free space")
-            HDassert(f->shared->fs_man[ty]);
-	    fs_started = TRUE;
-	} /* end if */
-
-	/* Check if f there's free space sections of this type */
-        if(f->shared->fs_man[ty]) {
-            hsize_t hnums = 0;          /* Total # of sections */
-            size_t nums;                /* Total # of sections, cast to a size_t */
-
-            /* Query how many sections of this type */
-	    if(H5FS_sect_stats(f->shared->fs_man[ty], NULL, &hnums) < 0)
-		HGOTO_ERROR(H5E_RESOURCE, H5E_CANTGET, FAIL, "can't query free space stats")
-            H5_CHECKED_ASSIGN(nums, size_t, hnums, hsize_t);
-
-            /* Increment total # of sections */
-            total_sects += nums;
-
-            /* Check if we should retrieve the section info */
-            if(sect_info && nums > 0) {
-                /* Iterate over all the free space sections of this type, adding them to the user's section info */
-                if(H5FS_sect_iterate(f, dxpl_id, f->shared->fs_man[ty], H5MF_sects_cb, &sect_udata) < 0)
-                    HGOTO_ERROR(H5E_RESOURCE, H5E_BADITER, FAIL, "can't iterate over sections")
-            } /* end if */
+        if(lg_fshdr_fs_type != lg_fssinfo_fs_type && f->shared->fs_man[lg_fssinfo_fs_type]) {
+            /* Sanity check: Query free space manager info for this type */
+            if(H5FS_stat_info(f, f->shared->fs_man[lg_fssinfo_fs_type], &fs_stat) < 0)
+                HGOTO_ERROR(H5E_RESOURCE, H5E_CANTGET, FAIL, "can't get free-space info")
+
+            HDassert(H5F_addr_defined(fs_stat.addr));
+            HDassert(H5F_addr_defined(fs_stat.sect_addr));
+            if(H5FS_free(f, f->shared->fs_man[lg_fssinfo_fs_type], dxpl_id, FALSE) < 0)
+                HGOTO_ERROR(H5E_RESOURCE, H5E_CANTRELEASE, FAIL, "can't float free-space headers")
+            f->shared->fs_addr[lg_fssinfo_fs_type] = HADDR_UNDEF;
         } /* end if */
+    } /* end if */
 
-	/* Close the free space manager of this type, if we started it here */
-        if(fs_started)
-            if(H5MF__alloc_close(f, dxpl_id, ty) < 0)
-	        HGOTO_ERROR(H5E_RESOURCE, H5E_CANTCLOSEOBJ, FAIL, "can't close file free space")
-    } /* end for */
+    /* 5) Set EOA equal to f->shared->eoa_pre_fsm_fsalloc, 
+     *    and then set f->shared->eoa_pre_fsm_fsalloc to 
+     *    HADDR_UNDEF.
+     *
+     *    If page buffering, verify that the new EOA is 
+     *    on a page boundary, and expunge any pages in the 
+     *    page buffer after the new EOA.
+     */
+    if(!H5F_PAGED_AGGR(f)) {
+        /* Verify that the aggregators are still shutdown. */
+        HDassert(f->shared->sdata_aggr.tot_size == 0);
+        HDassert(f->shared->sdata_aggr.addr == 0);
+        HDassert(f->shared->sdata_aggr.size == 0);
 
-    /* Set return value */
-    ret_value = (ssize_t)total_sects;
+        HDassert(f->shared->meta_aggr.tot_size == 0);
+        HDassert(f->shared->meta_aggr.addr == 0);
+        HDassert(f->shared->meta_aggr.size == 0);
+    } /* end if */
+
+    tail_size = (hsize_t)(eoa - f->shared->eoa_pre_fsm_fsalloc);
+
+    /* Release file space allocated to self referential FSMs */
+    if(H5F_free(f, dxpl_id, H5FD_MEM_DEFAULT, f->shared->eoa_pre_fsm_fsalloc, tail_size) < 0)
+        HGOTO_ERROR(H5E_RESOURCE, H5E_CANTFREE, FAIL, "driver free request failed")
+    if(HADDR_UNDEF == (eoa = H5FD_get_eoa(f->shared->lf, H5FD_MEM_DEFAULT)))
+        HGOTO_ERROR(H5E_FILE, H5E_CANTGET, FAIL, "unable to get EOA")
+    HDassert(H5F_addr_eq(f->shared->eoa_pre_fsm_fsalloc, eoa));
+
+    f->shared->eoa_pre_fsm_fsalloc = HADDR_UNDEF;
+
+    HDassert((!H5F_PAGED_AGGR(f)) || (0 == (eoa % f->shared->fs_page_size)));
 
 done:
     /* Reset the ring in the DXPL */
@@ -2359,5 +3911,5 @@ done:
             HDONE_ERROR(H5E_RESOURCE, H5E_CANTSET, FAIL, "unable to set property value")
 
     FUNC_LEAVE_NOAPI_TAG(ret_value, FAIL)
-} /* H5MF_get_free_sections() */
+} /* H5MF_tidy_self_referential_fsm_hack() */
 
diff --git a/src/H5MFaggr.c b/src/H5MFaggr.c
index 1510645..de98bf1 100644
--- a/src/H5MFaggr.c
+++ b/src/H5MFaggr.c
@@ -57,8 +57,10 @@
 /********************/
 /* Local Prototypes */
 /********************/
-static herr_t H5MF_aggr_free(H5F_t *f, hid_t dxpl_id, H5FD_mem_t type,
+static herr_t H5MF__aggr_free(H5F_t *f, hid_t dxpl_id, H5FD_mem_t type,
     H5F_blk_aggr_t *aggr);
+static haddr_t H5MF__aggr_alloc(H5F_t *f, hid_t dxpl_id, H5F_blk_aggr_t *aggr,
+    H5F_blk_aggr_t *other_aggr, H5FD_mem_t type, hsize_t size);
 
 
 /*********************/
@@ -78,86 +80,9 @@ static herr_t H5MF_aggr_free(H5F_t *f, hid_t dxpl_id, H5FD_mem_t type,
 
 
 /*-------------------------------------------------------------------------
- * Function:    H5MF_vfd_alloc
- *
- * Purpose:     Allocate SIZE bytes of file memory via H5FD_alloc() and return
- *              the relative address where that contiguous chunk of file memory
- *              exists.
- *		The TYPE argument describes the purpose for which the storage
- *		is being requested.
- *
- * Return:      Success:        The file address of new chunk.
- *              Failure:        HADDR_UNDEF
- *
- * Programmer:  Quincey Koziol
- *              January 2, 2017
- *
- *-------------------------------------------------------------------------
- */
-haddr_t
-H5MF_vfd_alloc(H5F_t *f, hid_t dxpl_id, H5FD_mem_t alloc_type, hsize_t size,
-    hbool_t keep_fragment)
-{
-    haddr_t eoa;                        /* Initial EOA for the file */
-    haddr_t eoa_frag_addr = HADDR_UNDEF; /* Address of fragment at EOA */
-    hsize_t eoa_frag_size = 0;          /* Size of fragment at EOA */
-    haddr_t ret_value = HADDR_UNDEF;    /* Return value */
-
-    FUNC_ENTER_NOAPI(HADDR_UNDEF)
-#ifdef H5MF_ALLOC_DEBUG
-HDfprintf(stderr, "%s: alloc_type = %u, size = %Hu\n", FUNC, (unsigned)alloc_type, size);
-#endif /* H5MF_ALLOC_DEBUG */
-
-    /* check arguments */
-    HDassert(f);
-    HDassert(f->shared);
-    HDassert(f->shared->lf);
-    HDassert(size > 0);
-
-    /* Get the EOA for the file -- need for sanity check below */
-    if(HADDR_UNDEF == (eoa = H5F_get_eoa(f, alloc_type)))
-       HGOTO_ERROR(H5E_RESOURCE, H5E_CANTGET, HADDR_UNDEF, "Unable to get eoa")
-
-    /* Check for overlap into temporary allocation space */
-    if(H5F_addr_gt((eoa + size), f->shared->tmp_addr))
-        HGOTO_ERROR(H5E_RESOURCE, H5E_BADRANGE, HADDR_UNDEF, "hdr file space alloc will overlap into 'temporary' file space")
-
-    /* Allocate space for the header */
-    if(HADDR_UNDEF == (ret_value = H5FD_alloc(f->shared->lf, dxpl_id, alloc_type, f, size, &eoa_frag_addr, &eoa_frag_size)))
-        HGOTO_ERROR(H5E_RESOURCE, H5E_CANTALLOC, HADDR_UNDEF, "can't allocate file space for hdr")
-
-    /* Sanity check for overlapping into file's temporary allocation space */
-    HDassert(H5F_addr_le((ret_value + size), f->shared->tmp_addr));
-
-    /* If the file alignment is 1, there should be no eoa fragment */
-    HDassert((eoa_frag_size == 0) || (f->shared->alignment != 1));
-
-    /* Check if fragment was generated and we want to keep it */
-    if(keep_fragment && eoa_frag_size > 0) {
-        /* Sanity check */
-        HDassert(H5F_addr_defined(eoa_frag_addr));
-
-        /* Put fragment on the free list */
-        if(H5MF_xfree(f, alloc_type, dxpl_id, eoa_frag_addr, eoa_frag_size) < 0)
-            HGOTO_ERROR(H5E_RESOURCE, H5E_CANTFREE, HADDR_UNDEF, "can't free eoa fragment")
-    } /* end if */
-
-done:
-#ifdef H5MF_ALLOC_DEBUG
-HDfprintf(stderr, "%s: Leaving: ret_value = %a, size = %Hu\n", FUNC, ret_value, size);
-#endif /* H5MF_ALLOC_DEBUG */
-#ifdef H5MF_ALLOC_DEBUG_DUMP
-H5MF_sects_dump(f, dxpl_id, stderr);
-#endif /* H5MF_ALLOC_DEBUG_DUMP */
-
-    FUNC_LEAVE_NOAPI(ret_value)
-} /* end H5MF_vfd_alloc() */
-
-
-/*-------------------------------------------------------------------------
  * Function:    H5MF_aggr_vfd_alloc
  *
- * Purpose:     Allocate SIZE bytes of file memory via H5MF_aggr_alloc()
+ * Purpose:     Allocate SIZE bytes of file memory via H5MF__aggr_alloc()
  *		and return the relative address where that contiguous chunk
  *		of file memory exists.
  *		The TYPE argument describes the purpose for which the storage
@@ -177,9 +102,9 @@ H5MF_aggr_vfd_alloc(H5F_t *f, H5FD_mem_t alloc_type, hid_t dxpl_id, hsize_t size
     haddr_t     ret_value = HADDR_UNDEF;        /* Return value */
 
     FUNC_ENTER_NOAPI(HADDR_UNDEF)
-#ifdef H5MF_ALLOC_DEBUG
+#ifdef H5MF_AGGR_DEBUG
 HDfprintf(stderr, "%s: alloc_type = %u, size = %Hu\n", FUNC, (unsigned)alloc_type, size);
-#endif /* H5MF_ALLOC_DEBUG */
+#endif /* H5MF_AGGR_DEBUG */
 
     /* check arguments */
     HDassert(f);
@@ -190,12 +115,12 @@ HDfprintf(stderr, "%s: alloc_type = %u, size = %Hu\n", FUNC, (unsigned)alloc_typ
     /* Couldn't find anything from the free space manager, go allocate some */
     if(alloc_type != H5FD_MEM_DRAW && alloc_type != H5FD_MEM_GHEAP) {
         /* Handle metadata differently from "raw" data */
-        if(HADDR_UNDEF == (ret_value = H5MF_aggr_alloc(f, dxpl_id, &(f->shared->meta_aggr), &(f->shared->sdata_aggr), alloc_type, size)))
+        if(HADDR_UNDEF == (ret_value = H5MF__aggr_alloc(f, dxpl_id, &(f->shared->meta_aggr), &(f->shared->sdata_aggr), alloc_type, size)))
             HGOTO_ERROR(H5E_RESOURCE, H5E_CANTALLOC, HADDR_UNDEF, "can't allocate metadata")
     } /* end if */
     else {
         /* Allocate "raw" data: H5FD_MEM_DRAW and H5FD_MEM_GHEAP */
-        if(HADDR_UNDEF == (ret_value = H5MF_aggr_alloc(f, dxpl_id, &(f->shared->sdata_aggr), &(f->shared->meta_aggr), H5FD_MEM_DRAW, size)))
+        if(HADDR_UNDEF == (ret_value = H5MF__aggr_alloc(f, dxpl_id, &(f->shared->sdata_aggr), &(f->shared->meta_aggr), H5FD_MEM_DRAW, size)))
             HGOTO_ERROR(H5E_RESOURCE, H5E_CANTALLOC, HADDR_UNDEF, "can't allocate raw data")
     } /* end else */
 
@@ -203,19 +128,16 @@ HDfprintf(stderr, "%s: alloc_type = %u, size = %Hu\n", FUNC, (unsigned)alloc_typ
     HDassert(H5F_addr_le((ret_value + size), f->shared->tmp_addr));
 
 done:
-#ifdef H5MF_ALLOC_DEBUG
+#ifdef H5MF_AGGR_DEBUG
 HDfprintf(stderr, "%s: Leaving: ret_value = %a, size = %Hu\n", FUNC, ret_value, size);
-#endif /* H5MF_ALLOC_DEBUG */
-#ifdef H5MF_ALLOC_DEBUG_DUMP
-H5MF_sects_dump(f, dxpl_id, stderr);
-#endif /* H5MF_ALLOC_DEBUG_DUMP */
+#endif /* H5MF_AGGR_DEBUG */
 
     FUNC_LEAVE_NOAPI(ret_value)
 } /* end H5MF_aggr_vfd_alloc() */
 
 
 /*-------------------------------------------------------------------------
- * Function:    H5MF_aggr_alloc
+ * Function:    H5MF__aggr_alloc
  *
  * Purpose:     Try to allocate SIZE bytes of memory from an aggregator
  *              block if possible.
@@ -228,8 +150,8 @@ H5MF_sects_dump(f, dxpl_id, stderr);
  *
  *-------------------------------------------------------------------------
  */
-haddr_t
-H5MF_aggr_alloc(H5F_t *f, hid_t dxpl_id, H5F_blk_aggr_t *aggr,
+static haddr_t
+H5MF__aggr_alloc(H5F_t *f, hid_t dxpl_id, H5F_blk_aggr_t *aggr,
     H5F_blk_aggr_t *other_aggr, H5FD_mem_t type, hsize_t size)
 {
     haddr_t     eoa_frag_addr = HADDR_UNDEF;    /* Address of fragment at EOA */
@@ -237,7 +159,7 @@ H5MF_aggr_alloc(H5F_t *f, hid_t dxpl_id, H5F_blk_aggr_t *aggr,
     haddr_t	eoa = HADDR_UNDEF;      	/* Initial EOA for the file */
     haddr_t     ret_value = HADDR_UNDEF;        /* Return value */
 
-    FUNC_ENTER_NOAPI(HADDR_UNDEF)
+    FUNC_ENTER_STATIC
 #ifdef H5MF_AGGR_DEBUG
 HDfprintf(stderr, "%s: type = %u, size = %Hu\n", FUNC, (unsigned)type, size);
 #endif /* H5MF_AGGR_DEBUG */
@@ -257,11 +179,11 @@ HDfprintf(stderr, "%s: type = %u, size = %Hu\n", FUNC, (unsigned)type, size);
         HGOTO_ERROR(H5E_RESOURCE, H5E_CANTGET, HADDR_UNDEF, "Unable to get eoa")
 
     /*
-     * If the aggregation feature is enabled for this file and strategy is not H5F_FILE_SPACE_VFD,
+     * If the aggregation feature is enabled for this file and strategy is not H5F_FILE_SPACE_NONE,
      * allocate "generic" space and sub-allocate out of that, if possible.
-     * Otherwise just allocate through H5FD_alloc().
+     * Otherwise just allocate through H5F_alloc().
      */
-    if((f->shared->feature_flags & aggr->feature_flag) && f->shared->fs_strategy != H5F_FILE_SPACE_VFD) {
+    if((f->shared->feature_flags & aggr->feature_flag) && f->shared->fs_strategy != H5F_FSPACE_STRATEGY_NONE) {
         haddr_t	aggr_frag_addr = HADDR_UNDEF;   /* Address of aggregrator fragment */
         hsize_t	aggr_frag_size = 0;             /* Size of aggregator fragment */
         hsize_t alignment;                      /* Alignment of this section */
@@ -273,12 +195,12 @@ HDfprintf(stderr, "%s: aggr = {%a, %Hu, %Hu}\n", FUNC, aggr->addr, aggr->tot_siz
 #endif /* H5MF_AGGR_DEBUG */
 
         /* Turn off alignment if allocation < threshold */
-	alignment = f->shared->alignment;
-	if(!((alignment > 1) && (size >= f->shared->threshold)))
+	alignment = H5F_ALIGNMENT(f);
+	if(!((alignment > 1) && (size >= H5F_THRESHOLD(f))))
 	    alignment = 0; /* no alignment */
 
         /* Generate fragment if aggregator is mis-aligned */
-	if(alignment && aggr->addr > 0 && (aggr_mis_align = (aggr->addr + H5FD_get_base_addr(f->shared->lf)) % alignment)) {
+	if(alignment && H5F_addr_gt(aggr->addr, 0) && (aggr_mis_align = (aggr->addr + H5F_BASE_ADDR(f)) % alignment)) {
 	    aggr_frag_addr = aggr->addr;
 	    aggr_frag_size = alignment - aggr_mis_align;
 	} /* end if */
@@ -288,7 +210,7 @@ HDfprintf(stderr, "%s: aggr = {%a, %Hu, %Hu}\n", FUNC, aggr->addr, aggr->tot_siz
 
         /* Check if the space requested is larger than the space left in the block */
         if((size + aggr_frag_size) > aggr->size) {
-            htri_t  	was_extended = FALSE;   /* Whether the file was extended */
+            htri_t  	extended = FALSE;   /* Whether the file was extended */
 
             /* Check if the block asked for is too large for 'normal' aggregator block */
             if(size >= aggr->alloc_size) {
@@ -298,32 +220,27 @@ HDfprintf(stderr, "%s: aggr = {%a, %Hu, %Hu}\n", FUNC, aggr->addr, aggr->tot_siz
                 if(H5F_addr_gt((aggr->addr + aggr->size + ext_size), f->shared->tmp_addr))
                     HGOTO_ERROR(H5E_RESOURCE, H5E_BADRANGE, HADDR_UNDEF, "'normal' file space allocation request will overlap into 'temporary' file space")
 
-		if((aggr->addr > 0) && (was_extended = H5FD_try_extend(f->shared->lf, alloc_type, f, dxpl_id, aggr->addr + aggr->size, ext_size)) < 0)
+		if((aggr->addr > 0) && (extended = H5F_try_extend(f, dxpl_id, alloc_type, (aggr->addr + aggr->size), ext_size)) < 0)
 		    HGOTO_ERROR(H5E_RESOURCE, H5E_CANTALLOC, HADDR_UNDEF, "can't extending space")
-		else if(was_extended) {
+		else if (extended) {
 		    /* aggr->size is unchanged */
 		    ret_value = aggr->addr + aggr_frag_size;
 		    aggr->addr += ext_size;
 		    aggr->tot_size += ext_size;
-		} /* end else-if */
-		else {
-                    /* Check for overlapping into file's temporary allocation space */
-                    if(H5F_addr_gt((eoa + size), f->shared->tmp_addr))
-                        HGOTO_ERROR(H5E_RESOURCE, H5E_BADRANGE, HADDR_UNDEF, "'normal' file space allocation request will overlap into 'temporary' file space")
-
+		} else {
                     /* Release "other" aggregator, if it exists, is at the end of the allocated space,
                      * has allocated more than one block and the unallocated space is greater than its
                      * allocation block size.
                      */
 		    if((other_aggr->size > 0) && (H5F_addr_eq((other_aggr->addr + other_aggr->size), eoa)) &&
 			    (other_aggr->tot_size > other_aggr->size) && ((other_aggr->tot_size - other_aggr->size) >= other_aggr->alloc_size)) {
-                        if(H5MF_aggr_free(f, dxpl_id, other_alloc_type, other_aggr) < 0)
+                        if(H5MF__aggr_free(f, dxpl_id, other_alloc_type, other_aggr) < 0)
                             HGOTO_ERROR(H5E_RESOURCE, H5E_CANTFREE, HADDR_UNDEF, "can't free aggregation block")
 		    } /* end if */
 
                     /* Allocate space from the VFD (i.e. at the end of the file) */
-		    if(HADDR_UNDEF == (ret_value = H5FD_alloc(f->shared->lf, dxpl_id, alloc_type, f, size, &eoa_frag_addr, &eoa_frag_size)))
-			HGOTO_ERROR(H5E_RESOURCE, H5E_CANTALLOC, HADDR_UNDEF, "can't allocate aggregation block")
+		    if(HADDR_UNDEF == (ret_value = H5F_alloc(f, dxpl_id, alloc_type, size, &eoa_frag_addr, &eoa_frag_size)))
+			HGOTO_ERROR(H5E_RESOURCE, H5E_CANTALLOC, HADDR_UNDEF, "can't allocate file space")
                 } /* end else */
             } /* end if */
 	    else {
@@ -341,9 +258,9 @@ HDfprintf(stderr, "%s: Allocating block\n", FUNC);
                 if(H5F_addr_gt((aggr->addr + aggr->size + ext_size), f->shared->tmp_addr))
                     HGOTO_ERROR(H5E_RESOURCE, H5E_BADRANGE, HADDR_UNDEF, "'normal' file space allocation request will overlap into 'temporary' file space")
 
-		if((aggr->addr > 0) && (was_extended = H5FD_try_extend(f->shared->lf, alloc_type, f, dxpl_id, aggr->addr + aggr->size, ext_size)) < 0)
+		if((aggr->addr > 0) && (extended = H5F_try_extend(f, dxpl_id, alloc_type, (aggr->addr + aggr->size), ext_size)) < 0)
 		    HGOTO_ERROR(H5E_RESOURCE, H5E_CANTALLOC, HADDR_UNDEF, "can't extending space")
-		else if(was_extended) {
+		else if(extended) {
 		    aggr->addr += aggr_frag_size;
 		    aggr->size += (ext_size - aggr_frag_size);
 		    aggr->tot_size += ext_size;
@@ -351,23 +268,19 @@ HDfprintf(stderr, "%s: Allocating block\n", FUNC);
 		else {
                     haddr_t new_space;          /* Address of new space allocated */
 
-                    /* Check for overlapping into file's temporary allocation space */
-                    if(H5F_addr_gt((eoa + aggr->alloc_size), f->shared->tmp_addr))
-                        HGOTO_ERROR(H5E_RESOURCE, H5E_BADRANGE, HADDR_UNDEF, "'normal' file space allocation request will overlap into 'temporary' file space")
-
                     /* Release "other" aggregator, if it exists, is at the end of the allocated space,
                      * has allocated more than one block and the unallocated space is greater than its
                      * allocation block size.
                      */
 		    if((other_aggr->size > 0) && (H5F_addr_eq((other_aggr->addr + other_aggr->size), eoa)) &&
 			    (other_aggr->tot_size > other_aggr->size) && ((other_aggr->tot_size - other_aggr->size) >= other_aggr->alloc_size)) {
-                        if(H5MF_aggr_free(f, dxpl_id, other_alloc_type, other_aggr) < 0)
+                        if(H5MF__aggr_free(f, dxpl_id, other_alloc_type, other_aggr) < 0)
                             HGOTO_ERROR(H5E_RESOURCE, H5E_CANTFREE, HADDR_UNDEF, "can't free aggregation block")
 		    } /* end if */
 
                     /* Allocate space from the VFD (i.e. at the end of the file) */
-		    if(HADDR_UNDEF == (new_space = H5FD_alloc(f->shared->lf, dxpl_id, alloc_type, f, aggr->alloc_size, &eoa_frag_addr, &eoa_frag_size)))
-			HGOTO_ERROR(H5E_RESOURCE, H5E_CANTALLOC, HADDR_UNDEF, "can't allocate aggregation block")
+		    if(HADDR_UNDEF == (new_space = H5F_alloc(f, dxpl_id, alloc_type, aggr->alloc_size, &eoa_frag_addr, &eoa_frag_size)))
+			HGOTO_ERROR(H5E_RESOURCE, H5E_CANTALLOC, HADDR_UNDEF, "can't allocate file space")
 
                     /* Return the unused portion of the block to a free list */
                     if(aggr->size > 0)
@@ -408,7 +321,7 @@ HDfprintf(stderr, "%s: Allocating block\n", FUNC);
 		    HGOTO_ERROR(H5E_RESOURCE, H5E_CANTFREE, HADDR_UNDEF, "can't free eoa fragment")
 
 	    /* Freeing any possible fragment due to alignment in the block after extension */
-	    if(was_extended && aggr_frag_size)
+            if(extended && aggr_frag_size)
 		if(H5MF_xfree(f, alloc_type, dxpl_id, aggr_frag_addr, aggr_frag_size) < 0)
 		    HGOTO_ERROR(H5E_RESOURCE, H5E_CANTFREE, HADDR_UNDEF, "can't free aggregation fragment")
         } /* end if */
@@ -425,12 +338,8 @@ HDfprintf(stderr, "%s: Allocating block\n", FUNC);
         } /* end else */
     } /* end if */
     else {
-        /* Check for overlapping into file's temporary allocation space */
-        if(H5F_addr_gt((eoa + size), f->shared->tmp_addr))
-            HGOTO_ERROR(H5E_RESOURCE, H5E_BADRANGE, HADDR_UNDEF, "'normal' file space allocation request will overlap into 'temporary' file space")
-
         /* Allocate data from the file */
-        if(HADDR_UNDEF == (ret_value = H5FD_alloc(f->shared->lf, dxpl_id, type, f, size, &eoa_frag_addr, &eoa_frag_size)))
+        if(HADDR_UNDEF == (ret_value = H5F_alloc(f, dxpl_id, type, size, &eoa_frag_addr, &eoa_frag_size)))
             HGOTO_ERROR(H5E_RESOURCE, H5E_CANTALLOC, HADDR_UNDEF, "can't allocate file space")
 
         /* Check if fragment was generated */
@@ -444,15 +353,15 @@ HDfprintf(stderr, "%s: Allocating block\n", FUNC);
     HDassert(H5F_addr_le((ret_value + size), f->shared->tmp_addr));
 
     /* Post-condition sanity check */
-    if(f->shared->alignment && size >= f->shared->threshold)
-	HDassert(!((ret_value + H5FD_get_base_addr(f->shared->lf)) % f->shared->alignment));
+    if(H5F_ALIGNMENT(f) && size >= H5F_THRESHOLD(f))
+        HDassert(!((ret_value + H5FD_get_base_addr(f->shared->lf)) % H5F_ALIGNMENT(f)));
 
 done:
 #ifdef H5MF_AGGR_DEBUG
 HDfprintf(stderr, "%s: ret_value = %a\n", FUNC, ret_value);
 #endif /* H5MF_AGGR_DEBUG */
     FUNC_LEAVE_NOAPI(ret_value)
-} /* end H5MF_aggr_alloc() */
+} /* end H5MF__aggr_alloc() */
 
 
 /*-------------------------------------------------------------------------
@@ -524,7 +433,7 @@ H5MF_aggr_try_extend(H5F_t *f, hid_t dxpl_id, H5F_blk_aggr_t *aggr,
 		else {
 		    hsize_t extra = (extra_requested < aggr->alloc_size) ? aggr->alloc_size : extra_requested;
 
-		    if((ret_value = H5FD_try_extend(f->shared->lf, type, f, dxpl_id, (aggr->addr + aggr->size), extra)) < 0)
+                    if((ret_value = H5F_try_extend(f, dxpl_id, type, (aggr->addr + aggr->size), extra)) < 0)
 			HGOTO_ERROR(H5E_RESOURCE, H5E_CANTEXTEND, FAIL, "error extending file")
 		    else if(ret_value == TRUE) {
 			/* Shift the aggregator block by the extra requested */
@@ -905,7 +814,7 @@ done:
 
 
 /*-------------------------------------------------------------------------
- * Function:    H5MF_aggr_free
+ * Function:    H5MF__aggr_free
  *
  * Purpose:     Free the aggregator's space in the file.
  *
@@ -919,11 +828,11 @@ done:
  *-------------------------------------------------------------------------
  */
 static herr_t
-H5MF_aggr_free(H5F_t *f, hid_t dxpl_id, H5FD_mem_t type, H5F_blk_aggr_t *aggr)
+H5MF__aggr_free(H5F_t *f, hid_t dxpl_id, H5FD_mem_t type, H5F_blk_aggr_t *aggr)
 {
     herr_t ret_value = SUCCEED;   	/* Return value */
 
-    FUNC_ENTER_NOAPI(FAIL)
+    FUNC_ENTER_STATIC
 
     /* Sanity check */
     HDassert(f);
@@ -936,7 +845,7 @@ H5MF_aggr_free(H5F_t *f, hid_t dxpl_id, H5FD_mem_t type, H5F_blk_aggr_t *aggr)
     HDassert(f->shared->feature_flags & aggr->feature_flag);
 
     /* Free the remaining space at EOA in the aggregator */
-    if(H5FD_free(f->shared->lf, dxpl_id, type, f, aggr->addr, aggr->size) < 0)
+    if(H5F_free(f, dxpl_id, type, aggr->addr, aggr->size) < 0)
         HGOTO_ERROR(H5E_RESOURCE, H5E_CANTFREE, FAIL, "can't free aggregation block")
 
     /* Reset the aggregator */
@@ -946,7 +855,7 @@ H5MF_aggr_free(H5F_t *f, hid_t dxpl_id, H5FD_mem_t type, H5F_blk_aggr_t *aggr)
 
 done:
     FUNC_LEAVE_NOAPI(ret_value)
-} /* H5MF_aggr_free() */
+} /* H5MF__aggr_free() */
 
 
 /*-------------------------------------------------------------------------
@@ -978,13 +887,13 @@ H5MF_aggrs_try_shrink_eoa(H5F_t *f, hid_t dxpl_id)
     if((ma_status = H5MF_aggr_can_shrink_eoa(f, H5FD_MEM_DEFAULT, &(f->shared->meta_aggr))) < 0)
         HGOTO_ERROR(H5E_RESOURCE, H5E_CANTGET, FAIL, "can't query metadata aggregator stats")
     if(ma_status > 0)
-	if(H5MF_aggr_free(f, dxpl_id, H5FD_MEM_DEFAULT, &(f->shared->meta_aggr)) < 0)
+	if(H5MF__aggr_free(f, dxpl_id, H5FD_MEM_DEFAULT, &(f->shared->meta_aggr)) < 0)
 	    HGOTO_ERROR(H5E_RESOURCE, H5E_CANTSHRINK, FAIL, "can't check for shrinking eoa")
 
     if((sda_status = H5MF_aggr_can_shrink_eoa(f, H5FD_MEM_DRAW, &(f->shared->sdata_aggr))) < 0)
         HGOTO_ERROR(H5E_RESOURCE, H5E_CANTGET, FAIL, "can't query small data aggregator stats")
     if(sda_status > 0)
-	if(H5MF_aggr_free(f, dxpl_id, H5FD_MEM_DRAW, &(f->shared->sdata_aggr)) < 0)
+	if(H5MF__aggr_free(f, dxpl_id, H5FD_MEM_DRAW, &(f->shared->sdata_aggr)) < 0)
 	    HGOTO_ERROR(H5E_RESOURCE, H5E_CANTSHRINK, FAIL, "can't check for shrinking eoa")
 
     ret_value = (ma_status || sda_status);
diff --git a/src/H5MFdbg.c b/src/H5MFdbg.c
index 57bac9e..817ea00 100644
--- a/src/H5MFdbg.c
+++ b/src/H5MFdbg.c
@@ -116,7 +116,9 @@ H5MF_sects_debug_cb(H5FS_section_info_t *_sect, void *_udata)
     /* Print generic section information */
     HDfprintf(udata->stream, "%*s%-*s %s\n", udata->indent, "", udata->fwidth,
 	      "Section type:",
-	      (sect->sect_info.type == H5MF_FSPACE_SECT_SIMPLE ? "simple" : "unknown"));
+          (sect->sect_info.type == H5MF_FSPACE_SECT_SIMPLE ? "simple" : 
+          (sect->sect_info.type == H5MF_FSPACE_SECT_SMALL ? "small" : 
+          (sect->sect_info.type == H5MF_FSPACE_SECT_LARGE ? "large" : "unknown"))));
     HDfprintf(udata->stream, "%*s%-*s %a\n", udata->indent, "", udata->fwidth,
 	      "Section address:",
 	      sect->sect_info.addr);
@@ -171,7 +173,7 @@ H5MF_sects_debug(H5F_t *f, hid_t dxpl_id, haddr_t fs_addr, FILE *stream, int ind
     for(type = H5FD_MEM_DEFAULT; type < H5FD_MEM_NTYPES; H5_INC_ENUM(H5FD_mem_t, type))
 	if(H5F_addr_eq(f->shared->fs_addr[type], fs_addr)) {
 	    if(!f->shared->fs_man[type])
-		if(H5MF__alloc_open(f, dxpl_id, type) < 0)
+                if(H5MF_open_fstype(f, dxpl_id, type) < 0)
 		    HGOTO_ERROR(H5E_RESOURCE, H5E_CANTINIT, FAIL, "can't initialize file free space")
 
 	    if(f->shared->fs_man[type]) {
@@ -217,11 +219,6 @@ herr_t
 H5MF_sects_dump(H5F_t *f, hid_t dxpl_id, FILE *stream)
 {
     haddr_t eoa;                        /* End of allocated space in the file */
-    haddr_t ma_addr = HADDR_UNDEF;      /* Base "metadata aggregator" address */
-    hsize_t ma_size = 0;                /* Size of "metadata aggregator" */
-    haddr_t sda_addr = HADDR_UNDEF;     /* Base "small data aggregator" address */
-    hsize_t sda_size = 0;               /* Size of "small data aggregator" */
-    H5FD_mem_t type;                    /* Memory type for iteration */
     int indent = 0;                     /* Amount to indent */
     int fwidth = 50;                    /* Field width */
     herr_t ret_value = SUCCEED;         /* Return value */
@@ -244,56 +241,90 @@ HDfprintf(stderr, "%s: Dumping file free space sections\n", FUNC);
 HDfprintf(stderr, "%s: for type = H5FD_MEM_DEFAULT, eoa = %a\n", FUNC, eoa);
 #endif /* H5MF_ALLOC_DEBUG */
 
-    /* Retrieve metadata aggregator info, if available */
-    H5MF_aggr_query(f, &(f->shared->meta_aggr), &ma_addr, &ma_size);
-#ifdef H5MF_ALLOC_DEBUG
-HDfprintf(stderr, "%s: ma_addr = %a, ma_size = %Hu, end of ma = %a\n", FUNC, ma_addr, ma_size, (haddr_t)((ma_addr + ma_size) - 1));
-#endif /* H5MF_ALLOC_DEBUG */
+    if(H5F_PAGED_AGGR(f)) { /* File space paging */
+        H5F_mem_page_t ptype;		/* Memory type for iteration -- page fs */
 
-    /* Retrieve 'small data' aggregator info, if available */
-    H5MF_aggr_query(f, &(f->shared->sdata_aggr), &sda_addr, &sda_size);
-#ifdef H5MF_ALLOC_DEBUG
-HDfprintf(stderr, "%s: sda_addr = %a, sda_size = %Hu, end of sda = %a\n", FUNC, sda_addr, sda_size, (haddr_t)((sda_addr + sda_size) - 1));
-#endif /* H5MF_ALLOC_DEBUG */
-
-    /* Iterate over all the free space types that have managers and dump each free list's space */
-    for(type = H5FD_MEM_DEFAULT; type < H5FD_MEM_NTYPES; H5_INC_ENUM(H5FD_mem_t, type)) {
-        /* Print header for type */
-        HDfprintf(stream, "%*sFile Free Space Info for type = %u:\n", indent, "", (unsigned)type);
-
-        /* Check for this type being mapped to another type */
-        if(H5FD_MEM_DEFAULT == f->shared->fs_type_map[type] ||
-                type == f->shared->fs_type_map[type]) {
-            /* Retrieve the 'eoa' for this file memory type */
-            if(HADDR_UNDEF == (eoa = H5F_get_eoa(f, type)))
-                HGOTO_ERROR(H5E_RESOURCE, H5E_CANTGET, FAIL, "driver get_eoa request failed")
-            HDfprintf(stream, "%*s%-*s %a\n", indent + 3, "", MAX(0, fwidth - 3), "eoa:", eoa);
+        for(ptype = H5F_MEM_PAGE_META; ptype < H5F_MEM_PAGE_NTYPES; H5_INC_ENUM(H5F_mem_page_t, ptype)) {
+            /* Print header for type */
+            HDfprintf(stream, "%*sFile Free Space Info for type = %u:\n", indent, "", (unsigned)ptype);
 
             /* Print header for sections */
             HDfprintf(stream, "%*sSections:\n", indent + 3, "");
 
             /* If there is a free space manager for this type, iterate over them */
-            if(f->shared->fs_man[type]) {
+            if(f->shared->fs_man[ptype]) {
                 H5MF_debug_iter_ud_t udata;        /* User data for callbacks */
 
                 /* Prepare user data for section iteration callback */
-                udata.fspace = f->shared->fs_man[type];
+                udata.fspace = f->shared->fs_man[ptype];
                 udata.stream = stream;
                 udata.indent = indent + 6;
                 udata.fwidth = MAX(0, fwidth - 6);
 
                 /* Iterate over all the free space sections */
-                if(H5FS_sect_iterate(f, dxpl_id, f->shared->fs_man[type], H5MF_sects_debug_cb, &udata) < 0)
+                if(H5FS_sect_iterate(f, dxpl_id, f->shared->fs_man[ptype], H5MF_sects_debug_cb, &udata) < 0)
                     HGOTO_ERROR(H5E_HEAP, H5E_BADITER, FAIL, "can't iterate over heap's free space")
             } /* end if */
             else
                 /* No sections of this type */
                 HDfprintf(stream, "%*s<none>\n", indent + 6, "");
-        } /* end if */
-        else
-            HDfprintf(stream, "%*sMapped to type = %u\n", indent, "", (unsigned)f->shared->fs_type_map[type]);
+        } /* end for */
+    } /* end if */
+    else { /* not file space paging */
+        H5FD_mem_t atype;                   /* Memory type for iteration -- aggr fs */
+        haddr_t ma_addr = HADDR_UNDEF;      /* Base "metadata aggregator" address */
+        hsize_t ma_size = 0;                /* Size of "metadata aggregator" */
+        haddr_t sda_addr = HADDR_UNDEF;     /* Base "small data aggregator" address */
+        hsize_t sda_size = 0;               /* Size of "small data aggregator" */
+
+        /* Retrieve metadata aggregator info, if available */
+        H5MF_aggr_query(f, &(f->shared->meta_aggr), &ma_addr, &ma_size);
+#ifdef H5MF_ALLOC_DEBUG
+HDfprintf(stderr, "%s: ma_addr = %a, ma_size = %Hu, end of ma = %a\n", FUNC, ma_addr, ma_size, (haddr_t)((ma_addr + ma_size) - 1));
+#endif /* H5MF_ALLOC_DEBUG */
+
+        /* Retrieve 'small data' aggregator info, if available */
+        H5MF_aggr_query(f, &(f->shared->sdata_aggr), &sda_addr, &sda_size);
+#ifdef H5MF_ALLOC_DEBUG
+HDfprintf(stderr, "%s: sda_addr = %a, sda_size = %Hu, end of sda = %a\n", FUNC, sda_addr, sda_size, (haddr_t)((sda_addr + sda_size) - 1));
+#endif /* H5MF_ALLOC_DEBUG */
 
-    } /* end for */
+        /* Iterate over all the free space types that have managers and dump each free list's space */
+        for(atype = H5FD_MEM_DEFAULT; atype < H5FD_MEM_NTYPES; H5_INC_ENUM(H5FD_mem_t, atype)) {
+            /* Print header for type */
+            HDfprintf(stream, "%*sFile Free Space Info for type = %u:\n", indent, "", (unsigned)atype);
+
+            /* Check for this type being mapped to another type */
+            if(H5FD_MEM_DEFAULT == f->shared->fs_type_map[atype] || atype == f->shared->fs_type_map[atype]) {
+                /* Retrieve the 'eoa' for this file memory type */
+                if(HADDR_UNDEF == (eoa = H5F_get_eoa(f, atype)))
+                    HGOTO_ERROR(H5E_RESOURCE, H5E_CANTGET, FAIL, "driver get_eoa request failed")
+                HDfprintf(stream, "%*s%-*s %a\n", indent + 3, "", MAX(0, fwidth - 3), "eoa:", eoa);
+
+                /* Print header for sections */
+                HDfprintf(stream, "%*sSections:\n", indent + 3, "");
+
+                /* If there is a free space manager for this type, iterate over them */
+                if(f->shared->fs.aggr.fs_man[atype]) {
+                    H5MF_debug_iter_ud_t udata;        /* User data for callbacks */
+
+                    /* Prepare user data for section iteration callback */
+                    udata.fspace = f->shared->fs_man[atype];
+                    udata.stream = stream;
+                    udata.indent = indent + 6;
+                    udata.fwidth = MAX(0, fwidth - 6);
+
+                    /* Iterate over all the free space sections */
+                    if(H5FS_sect_iterate(f, dxpl_id, f->shared->fs_man[atype], H5MF_sects_debug_cb, &udata) < 0)
+                        HGOTO_ERROR(H5E_HEAP, H5E_BADITER, FAIL, "can't iterate over heap's free space")
+                } /* end if */
+                else /* No sections of this type */
+                    HDfprintf(stream, "%*s<none>\n", indent + 6, "");
+            } /* end if */
+            else
+                HDfprintf(stream, "%*sMapped to type = %u\n", indent, "", (unsigned)f->shared->fs_type_map[atype]);
+        } /* end for */
+    } /* end else */
 
 done:
 HDfprintf(stderr, "%s: Done dumping file free space sections\n", FUNC);
diff --git a/src/H5MFpkg.h b/src/H5MFpkg.h
index 43fc1cd..c4a0819 100644
--- a/src/H5MFpkg.h
+++ b/src/H5MFpkg.h
@@ -51,9 +51,38 @@
 /* Define this to dump free space tracker contents after they've been modified */
 /* #define H5MF_ALLOC_DEBUG_DUMP */
 
-/* Free space section types for file */
+/* Free-space section types for file */
 /* (values stored in free space data structures in file) */
-#define H5MF_FSPACE_SECT_SIMPLE         0       /* Section is a range of actual bytes in file */
+#define H5MF_FSPACE_SECT_SIMPLE     0   /* For non-paged aggregation: section is a range of actual bytes in file */
+#define H5MF_FSPACE_SECT_SMALL      1   /* For paged aggregation: "small" meta/raw data section which is < fsp_size) */
+#define H5MF_FSPACE_SECT_LARGE      2   /* For paged aggregation: "large" Section which is >= fsp_size) */
+
+/* For non-paged aggregation: map allocation request type to tracked free-space type */
+/* F -- pointer to H5F_t; T -- H5FD_mem_t */
+#define H5MF_ALLOC_TO_FS_AGGR_TYPE(F, T)                  \
+        ((H5FD_MEM_DEFAULT == (F)->shared->fs_type_map[T]) ? (T) : (F)->shared->fs_type_map[T])
+
+/* Get section class type based on size */
+#define H5MF_SECT_CLASS_TYPE(F, S)                          \
+        ((H5F_PAGED_AGGR(F)) ?                              \
+         ((S >= (F)->shared->fs_page_size) ? H5MF_FSPACE_SECT_LARGE : H5MF_FSPACE_SECT_SMALL) : H5MF_FSPACE_SECT_SIMPLE)
+
+/* Get section class cls */
+#define H5MF_SECT_CLS_TYPE(F, S)                            \
+        ((H5F_PAGED_AGGR(F)) ?                              \
+         ((S >= (F)->shared->fs_page_size) ?                \
+          H5MF_FSPACE_SECT_CLS_LARGE : H5MF_FSPACE_SECT_CLS_SMALL) : H5MF_FSPACE_SECT_CLS_SIMPLE)
+
+/* Calculate the mis-aligned fragment */
+#define H5MF_EOA_MISALIGN(F, E, A, FR)                                  \
+{                                                                       \
+    hsize_t m;                                                          \
+                                                                        \
+    if(H5F_addr_gt((E), 0) && ((m) = ((E) + H5F_BASE_ADDR(F)) % (A)))   \
+        (FR) = (A) - m;                                                 \
+    else                                                                \
+        (FR) = 0;                                                       \
+}
 
 
 /****************************/
@@ -129,6 +158,15 @@ typedef struct H5MF_sect_ud_t {
     H5F_blk_aggr_t *aggr;       /* Aggregator block to operate on */
 } H5MF_sect_ud_t;
 
+/* Information about the current free-space manager to use */
+typedef struct H5MF_fs_t {
+    H5F_fs_state_t *fs_state;
+    haddr_t *fs_addr;
+    H5FS_t **fs_man;
+    hsize_t     align_thres;	/* Threshold for alignment              */
+    hsize_t     alignment;      /* Alignment                            */
+} H5MF_fs_t;
+
 
 /*****************************/
 /* Package Private Variables */
@@ -136,6 +174,8 @@ typedef struct H5MF_sect_ud_t {
 
 /* H5MF single section inherits serializable properties from H5FS_section_class_t */
 H5_DLLVAR H5FS_section_class_t H5MF_FSPACE_SECT_CLS_SIMPLE[1];
+H5_DLLVAR H5FS_section_class_t H5MF_FSPACE_SECT_CLS_SMALL[1];
+H5_DLLVAR H5FS_section_class_t H5MF_FSPACE_SECT_CLS_LARGE[1];
 
 
 /******************************/
@@ -143,22 +183,23 @@ H5_DLLVAR H5FS_section_class_t H5MF_FSPACE_SECT_CLS_SIMPLE[1];
 /******************************/
 
 /* Allocator routines */
-H5_DLL herr_t H5MF__alloc_start(H5F_t *f, hid_t dxpl_id, H5FD_mem_t type);
-H5_DLL herr_t H5MF__alloc_open(H5F_t *f, hid_t dxpl_id, H5FD_mem_t type);
+H5_DLL herr_t H5MF_open_fstype(H5F_t *f, hid_t dxpl_id, H5F_mem_page_t type);
+H5_DLL herr_t H5MF_start_fstype(H5F_t *f, hid_t dxpl_id, H5F_mem_page_t type);
+
+H5_DLL htri_t H5MF_find_sect(H5F_t *f, H5FD_mem_t alloc_type, hid_t dxpl_id, hsize_t size, H5FS_t *fspace, haddr_t *addr);
+H5_DLL herr_t H5MF_add_sect(H5F_t *f, H5FD_mem_t alloc_type, hid_t dxpl_id, H5FS_t *fspace, H5MF_free_section_t *node);
+
 H5_DLL herr_t H5MF_sects_dump(H5F_t *f, hid_t dxpl_id, FILE *stream);
 
-/* 'simple' section routines */
-H5_DLL H5MF_free_section_t *H5MF_sect_simple_new(haddr_t sect_off,
+H5_DLL void H5MF_alloc_to_fs_type(H5F_t *f, H5FD_mem_t alloc_type, hsize_t size, H5F_mem_page_t *fs_type);
+
+/* 'simple/small/large' section routines */
+H5_DLL H5MF_free_section_t *H5MF_sect_new(unsigned ctype, haddr_t sect_off,
     hsize_t sect_size);
-H5_DLL htri_t H5MF_sect_simple_can_shrink(const H5FS_section_info_t *_sect,
-    void *udata);
-H5_DLL herr_t H5MF_sect_simple_shrink(H5FS_section_info_t **_sect,
-    void *udata);
-H5_DLL herr_t H5MF_sect_simple_free(H5FS_section_info_t *sect);
+H5_DLL herr_t H5MF_sect_free(H5FS_section_info_t *sect);
+
 
 /* Block aggregator routines */
-H5_DLL haddr_t H5MF_aggr_alloc(H5F_t *f, hid_t dxpl_id, H5F_blk_aggr_t *aggr,
-    H5F_blk_aggr_t *other_aggr, H5FD_mem_t type, hsize_t size);
 H5_DLL htri_t H5MF_aggr_try_extend(H5F_t *f, hid_t dxpl_id, H5F_blk_aggr_t *aggr,
     H5FD_mem_t type, haddr_t abs_blk_end, hsize_t extra_requested);
 H5_DLL htri_t H5MF_aggr_can_absorb(const H5F_t *f, const H5F_blk_aggr_t *aggr,
diff --git a/src/H5MFprivate.h b/src/H5MFprivate.h
index e258677..70322c3 100644
--- a/src/H5MFprivate.h
+++ b/src/H5MFprivate.h
@@ -58,8 +58,6 @@ H5_DLL herr_t H5MF_try_close(H5F_t *f, hid_t dxpl_id);
 /* File space allocation routines */
 H5_DLL haddr_t H5MF_alloc(H5F_t *f, H5FD_mem_t type, hid_t dxpl_id, hsize_t size);
 H5_DLL haddr_t H5MF_aggr_vfd_alloc(H5F_t *f, H5FD_mem_t type, hid_t dxpl_id, hsize_t size);
-H5_DLL haddr_t H5MF_vfd_alloc(H5F_t *f, hid_t dxpl_id, H5FD_mem_t alloc_type,
-    hsize_t size, hbool_t keep_fragment);
 H5_DLL herr_t H5MF_xfree(H5F_t *f, H5FD_mem_t type, hid_t dxpl_id, haddr_t addr,
     hsize_t size);
 H5_DLL herr_t H5MF_try_extend(H5F_t *f, hid_t dxpl_id, H5FD_mem_t type,
@@ -80,6 +78,14 @@ H5_DLL htri_t H5MF_aggrs_try_shrink_eoa(H5F_t *f, hid_t dxpl_id);
 H5_DLL herr_t H5MF_settle_raw_data_fsm(H5F_t *f, hid_t dxpl_id, hbool_t *fsm_settled);
 H5_DLL herr_t H5MF_settle_meta_data_fsm(H5F_t *f, hid_t dxpl_id, hbool_t *fsm_settled);
 
+/* This function has to be declared in H5MFprivate.h as it is needed 
+ * in our test code to allow us to manually start a self referential 
+ * free space manager prior to the first file space allocations / 
+ * deallocation without causing assertion failures on the first
+ * file space allocation / deallocation.
+ */
+H5_DLL herr_t H5MF_tidy_self_referential_fsm_hack(H5F_t *f, hid_t dxpl_id);
+
 /* Debugging routines */
 #ifdef H5MF_DEBUGGING
 H5_DLL herr_t H5MF_sects_debug(H5F_t *f, hid_t dxpl_id, haddr_t addr,
diff --git a/src/H5MFsection.c b/src/H5MFsection.c
index e5a0cf0..617cb59 100644
--- a/src/H5MFsection.c
+++ b/src/H5MFsection.c
@@ -57,18 +57,47 @@
 /* Local Prototypes */
 /********************/
 
-/* 'simple' section callbacks */
-static H5FS_section_info_t *H5MF_sect_simple_deserialize(const H5FS_section_class_t *cls,
+/* 'simple/small/large' section callbacks */
+static H5FS_section_info_t *H5MF_sect_deserialize(const H5FS_section_class_t *cls,
     hid_t dxpl_id, const uint8_t *buf, haddr_t sect_addr, hsize_t sect_size,
     unsigned *des_flags);
+static herr_t H5MF_sect_valid(const H5FS_section_class_t *cls,
+    const H5FS_section_info_t *sect, hid_t dxpl_id);
+static H5FS_section_info_t *H5MF_sect_split(H5FS_section_info_t *sect,
+    hsize_t frag_size);
+
+
+/* 'simple' section callbacks */
 static htri_t H5MF_sect_simple_can_merge(const H5FS_section_info_t *sect1,
     const H5FS_section_info_t *sect2, void *udata);
-static herr_t H5MF_sect_simple_merge(H5FS_section_info_t *sect1,
+static herr_t H5MF_sect_simple_merge(H5FS_section_info_t **sect1,
     H5FS_section_info_t *sect2, void *udata);
-static herr_t H5MF_sect_simple_valid(const H5FS_section_class_t *cls,
-    const H5FS_section_info_t *sect, hid_t dxpl_id);
-static H5FS_section_info_t *H5MF_sect_simple_split(H5FS_section_info_t *sect,
-    hsize_t frag_size);
+static htri_t H5MF_sect_simple_can_shrink(const H5FS_section_info_t *_sect,
+    void *udata);
+static herr_t H5MF_sect_simple_shrink(H5FS_section_info_t **_sect,
+    void *udata);
+
+
+/* 'small' section callbacks */
+static herr_t H5MF_sect_small_add(H5FS_section_info_t **_sect, unsigned *flags, void *_udata);
+static htri_t H5MF_sect_small_can_merge(const H5FS_section_info_t *sect1,
+    const H5FS_section_info_t *sect2, void *udata);
+static herr_t H5MF_sect_small_merge(H5FS_section_info_t **sect1,
+    H5FS_section_info_t *sect2, void *udata);
+static htri_t H5MF_sect_small_can_shrink(const H5FS_section_info_t *_sect,
+    void *udata);
+static herr_t H5MF_sect_small_shrink(H5FS_section_info_t **_sect,
+    void *udata);
+
+/* 'large' section callbacks */
+static htri_t H5MF_sect_large_can_merge(const H5FS_section_info_t *sect1,
+    const H5FS_section_info_t *sect2, void *udata);
+static herr_t H5MF_sect_large_merge(H5FS_section_info_t **sect1,
+    H5FS_section_info_t *sect2, void *udata);
+static htri_t H5MF_sect_large_can_shrink(const H5FS_section_info_t *_sect,
+    void *udata);
+static herr_t H5MF_sect_large_shrink(H5FS_section_info_t **_sect,
+    void *udata);
 
 /*********************/
 /* Package Variables */
@@ -89,17 +118,68 @@ H5FS_section_class_t H5MF_FSPACE_SECT_CLS_SIMPLE[1] = {{
     /* Object methods */
     NULL,				/* Add section                  */
     NULL,				/* Serialize section            */
-    H5MF_sect_simple_deserialize,	/* Deserialize section          */
+    H5MF_sect_deserialize,		/* Deserialize section          */
     H5MF_sect_simple_can_merge,		/* Can sections merge?          */
     H5MF_sect_simple_merge,		/* Merge sections               */
     H5MF_sect_simple_can_shrink,	/* Can section shrink container?*/
     H5MF_sect_simple_shrink,		/* Shrink container w/section   */
-    H5MF_sect_simple_free,		/* Free section                 */
-    H5MF_sect_simple_valid,		/* Check validity of section    */
-    H5MF_sect_simple_split,		/* Split section node for alignment */
+    H5MF_sect_free,			/* Free section                 */
+    H5MF_sect_valid,			/* Check validity of section    */
+    H5MF_sect_split,			/* Split section node for alignment */
     NULL,				/* Dump debugging for section   */
 }};
 
+/* Class info for "small" free space sections */
+H5FS_section_class_t H5MF_FSPACE_SECT_CLS_SMALL[1] = {{
+    /* Class variables */
+    H5MF_FSPACE_SECT_SMALL,		/* Section type                 */
+    0,					/* Extra serialized size        */
+    H5FS_CLS_MERGE_SYM | H5FS_CLS_ADJUST_OK, /* Class flags                  */
+    NULL,				/* Class private info           */
+
+    /* Class methods */
+    NULL,				/* Initialize section class     */
+    NULL,				/* Terminate section class      */
+
+    /* Object methods */
+    H5MF_sect_small_add,		/* Add section                  */
+    NULL,				/* Serialize section            */
+    H5MF_sect_deserialize,		/* Deserialize section          */
+    H5MF_sect_small_can_merge,		/* Can sections merge?          */
+    H5MF_sect_small_merge,		/* Merge sections               */
+    H5MF_sect_small_can_shrink,		/* Can section shrink container?*/
+    H5MF_sect_small_shrink,		/* Shrink container w/section   */
+    H5MF_sect_free,			/* Free section                 */
+    H5MF_sect_valid,			/* Check validity of section    */
+    H5MF_sect_split,			/* Split section node for alignment */
+    NULL,				/* Dump debugging for section   */
+}};
+
+/* Class info for "large" free space sections */
+H5FS_section_class_t H5MF_FSPACE_SECT_CLS_LARGE[1] = {{
+    /* Class variables */
+    H5MF_FSPACE_SECT_LARGE,		/* Section type                 */
+    0,					/* Extra serialized size        */
+    H5FS_CLS_MERGE_SYM | H5FS_CLS_ADJUST_OK, /* Class flags                  */
+    NULL,				/* Class private info           */
+
+    /* Class methods */
+    NULL,				/* Initialize section class     */
+    NULL,				/* Terminate section class      */
+
+    /* Object methods */
+    NULL,				/* Add section                  */
+    NULL,				/* Serialize section            */
+    H5MF_sect_deserialize,		/* Deserialize section          */
+    H5MF_sect_large_can_merge,		/* Can sections merge?          */
+    H5MF_sect_large_merge,		/* Merge sections               */
+    H5MF_sect_large_can_shrink,		/* Can section shrink container?*/
+    H5MF_sect_large_shrink,		/* Shrink container w/section   */
+    H5MF_sect_free,			/* Free section                 */
+    H5MF_sect_valid,			/* Check validity of section    */
+    H5MF_sect_split,			/* Split section node for alignment */
+    NULL,				/* Dump debugging for section   */
+}};
 
 /*****************************/
 /* Library Private Variables */
@@ -113,12 +193,15 @@ H5FS_section_class_t H5MF_FSPACE_SECT_CLS_SIMPLE[1] = {{
 /* Declare a free list to manage the H5MF_free_section_t struct */
 H5FL_DEFINE(H5MF_free_section_t);
 
+/* 
+ * "simple/small/large" section callbacks
+ */
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5MF_sect_simple_new
+ * Function:	H5MF_sect_new
  *
- * Purpose:	Create a new 'simple' section and return it to the caller
+ * Purpose:	Create a new section of "ctype" and return it to the caller
  *
  * Return:	Pointer to new section on success/NULL on failure
  *
@@ -129,9 +212,9 @@ H5FL_DEFINE(H5MF_free_section_t);
  *-------------------------------------------------------------------------
  */
 H5MF_free_section_t *
-H5MF_sect_simple_new(haddr_t sect_off, hsize_t sect_size)
+H5MF_sect_new(unsigned ctype, haddr_t sect_off, hsize_t sect_size)
 {
-    H5MF_free_section_t *sect = NULL;   /* 'Simple' free space section to add */
+    H5MF_free_section_t *sect;          /* 'Simple' free space section to add */
     H5MF_free_section_t *ret_value = NULL;      /* Return value */
 
     FUNC_ENTER_NOAPI_NOINIT
@@ -148,7 +231,7 @@ H5MF_sect_simple_new(haddr_t sect_off, hsize_t sect_size)
     sect->sect_info.size = sect_size;
 
     /* Set the section's class & state */
-    sect->sect_info.type = H5MF_FSPACE_SECT_SIMPLE;
+    sect->sect_info.type = ctype;
     sect->sect_info.state = H5FS_SECT_LIVE;
 
     /* Set return value */
@@ -156,13 +239,43 @@ H5MF_sect_simple_new(haddr_t sect_off, hsize_t sect_size)
 
 done:
     FUNC_LEAVE_NOAPI(ret_value)
-} /* end H5MF_sect_simple_new() */
+} /* end H5MF_sect_new() */
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5MF_sect_simple_deserialize
+ * Function:	H5MF_sect_free
  *
- * Purpose:	Deserialize a buffer into a "live" single section
+ * Purpose:	Free a 'simple/small/large' section node
+ *
+ * Return:	Success:	non-negative
+ *		Failure:	negative
+ *
+ * Programmer:	Quincey Koziol
+ *              Tuesday, January  8, 2008
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5MF_sect_free(H5FS_section_info_t *_sect)
+{
+    H5MF_free_section_t *sect = (H5MF_free_section_t *)_sect;   /* File free section */
+
+    FUNC_ENTER_NOAPI_NOINIT_NOERR
+
+    /* Check arguments. */
+    HDassert(sect);
+
+    /* Release the section */
+    sect = H5FL_FREE(H5MF_free_section_t, sect);
+
+    FUNC_LEAVE_NOAPI(SUCCEED)
+}   /* H5MF_sect_free() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:	H5MF_sect_deserialize
+ *
+ * Purpose:	Deserialize a buffer into a "live" section
  *
  * Return:	Success:	non-negative
  *		Failure:	negative
@@ -173,7 +286,7 @@ done:
  *-------------------------------------------------------------------------
  */
 static H5FS_section_info_t *
-H5MF_sect_simple_deserialize(const H5FS_section_class_t H5_ATTR_UNUSED *cls,
+H5MF_sect_deserialize(const H5FS_section_class_t *cls,
     hid_t H5_ATTR_UNUSED dxpl_id, const uint8_t H5_ATTR_UNUSED *buf, haddr_t sect_addr,
     hsize_t sect_size, unsigned H5_ATTR_UNUSED *des_flags)
 {
@@ -183,11 +296,12 @@ H5MF_sect_simple_deserialize(const H5FS_section_class_t H5_ATTR_UNUSED *cls,
     FUNC_ENTER_NOAPI_NOINIT
 
     /* Check arguments. */
+    HDassert(cls);
     HDassert(H5F_addr_defined(sect_addr));
     HDassert(sect_size);
 
     /* Create free space section for block */
-    if(NULL == (sect = H5MF_sect_simple_new(sect_addr, sect_size)))
+    if(NULL == (sect = H5MF_sect_new(cls->type, sect_addr, sect_size)))
         HGOTO_ERROR(H5E_RESOURCE, H5E_CANTALLOC, NULL, "can't initialize free space section")
 
     /* Set return value */
@@ -195,10 +309,80 @@ H5MF_sect_simple_deserialize(const H5FS_section_class_t H5_ATTR_UNUSED *cls,
 
 done:
     FUNC_LEAVE_NOAPI(ret_value)
-} /* H5MF_sect_simple_deserialize() */
+} /* H5MF_sect_deserialize() */
 
 
 /*-------------------------------------------------------------------------
+ * Function:	H5MF_sect_valid
+ *
+ * Purpose:	Check the validity of a section
+ *
+ * Return:	Success:	non-negative
+ *          Failure:	negative
+ *
+ * Programmer:	Quincey Koziol
+ *              Tuesday, January  8, 2008
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+H5MF_sect_valid(const H5FS_section_class_t H5_ATTR_UNUSED *cls,
+    const H5FS_section_info_t
+#ifdef NDEBUG
+    H5_ATTR_UNUSED
+#endif /* NDEBUG */
+    *_sect, hid_t H5_ATTR_UNUSED dxpl_id)
+{
+#ifndef NDEBUG
+    const H5MF_free_section_t *sect = (const H5MF_free_section_t *)_sect;   /* File free section */
+#endif /* NDEBUG */
+
+    FUNC_ENTER_NOAPI_NOINIT_NOERR
+
+    /* Check arguments. */
+    HDassert(sect);
+
+    FUNC_LEAVE_NOAPI(SUCCEED)
+}   /* H5MF_sect_valid() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:	H5MF_sect_split
+ *
+ * Purpose:	Split SECT into 2 sections: fragment for alignment & the aligned section
+ *          SECT's addr and size are updated to point to the aligned section
+ *
+ * Return:	Success:	the fragment for aligning sect
+ *          Failure:	null
+ *
+ * Programmer:	Vailin Choi, July 29, 2008
+ *
+ *-------------------------------------------------------------------------
+ */
+static H5FS_section_info_t *
+H5MF_sect_split(H5FS_section_info_t *sect, hsize_t frag_size)
+{
+    H5MF_free_section_t *ret_value;     /* Return value */
+
+    FUNC_ENTER_NOAPI_NOINIT
+
+    /* Allocate space for new section */
+    if(NULL == (ret_value = H5MF_sect_new(sect->type, sect->addr, frag_size)))
+        HGOTO_ERROR(H5E_RESOURCE, H5E_CANTALLOC, NULL, "can't initialize free space section")
+
+    /* Set new section's info */
+    sect->addr += frag_size;
+    sect->size -= frag_size;
+
+done:
+    FUNC_LEAVE_NOAPI((H5FS_section_info_t *)ret_value)
+} /* end H5MF_sect_split() */
+
+/* 
+ * "simple" section callbacks
+ */
+
+/*-------------------------------------------------------------------------
  * Function:	H5MF_sect_simple_can_merge
  *
  * Purpose:	Can two sections of this type merge?
@@ -252,10 +436,10 @@ H5MF_sect_simple_can_merge(const H5FS_section_info_t *_sect1,
  *-------------------------------------------------------------------------
  */
 static herr_t
-H5MF_sect_simple_merge(H5FS_section_info_t *_sect1, H5FS_section_info_t *_sect2,
+H5MF_sect_simple_merge(H5FS_section_info_t **_sect1, H5FS_section_info_t *_sect2,
     void H5_ATTR_UNUSED *_udata)
 {
-    H5MF_free_section_t *sect1 = (H5MF_free_section_t *)_sect1;   /* File free section */
+    H5MF_free_section_t **sect1 = (H5MF_free_section_t **)_sect1;   /* File free section */
     H5MF_free_section_t *sect2 = (H5MF_free_section_t *)_sect2;   /* File free section */
     herr_t ret_value = SUCCEED;         /* Return value */
 
@@ -263,16 +447,16 @@ H5MF_sect_simple_merge(H5FS_section_info_t *_sect1, H5FS_section_info_t *_sect2,
 
     /* Check arguments. */
     HDassert(sect1);
-    HDassert(sect1->sect_info.type == H5MF_FSPACE_SECT_SIMPLE);
+    HDassert((*sect1)->sect_info.type == H5MF_FSPACE_SECT_SIMPLE);
     HDassert(sect2);
     HDassert(sect2->sect_info.type == H5MF_FSPACE_SECT_SIMPLE);
-    HDassert(H5F_addr_eq(sect1->sect_info.addr + sect1->sect_info.size, sect2->sect_info.addr));
+    HDassert(H5F_addr_eq((*sect1)->sect_info.addr + (*sect1)->sect_info.size, sect2->sect_info.addr));
 
     /* Add second section's size to first section */
-    sect1->sect_info.size += sect2->sect_info.size;
+    (*sect1)->sect_info.size += sect2->sect_info.size;
 
     /* Get rid of second section */
-    if(H5MF_sect_simple_free((H5FS_section_info_t *)sect2) < 0)
+    if(H5MF_sect_free((H5FS_section_info_t *)sect2) < 0)
         HGOTO_ERROR(H5E_RESOURCE, H5E_CANTRELEASE, FAIL, "can't free section node")
 
 done:
@@ -293,7 +477,7 @@ done:
  *
  *-------------------------------------------------------------------------
  */
-htri_t
+static htri_t
 H5MF_sect_simple_can_shrink(const H5FS_section_info_t *_sect, void *_udata)
 {
     const H5MF_free_section_t *sect = (const H5MF_free_section_t *)_sect;   /* File free section */
@@ -392,7 +576,7 @@ done:
  *
  *-------------------------------------------------------------------------
  */
-herr_t
+static herr_t
 H5MF_sect_simple_shrink(H5FS_section_info_t **_sect, void *_udata)
 {
     H5MF_free_section_t **sect = (H5MF_free_section_t **)_sect;   /* File free section */
@@ -411,8 +595,8 @@ H5MF_sect_simple_shrink(H5FS_section_info_t **_sect, void *_udata)
         /* Sanity check */
         HDassert(H5F_INTENT(udata->f) & H5F_ACC_RDWR);
 
-        /* Release section's space at EOA with file driver */
-        if(H5FD_free(udata->f->shared->lf, udata->dxpl_id, udata->alloc_type, udata->f, (*sect)->sect_info.addr, (*sect)->sect_info.size) < 0)
+        /* Release section's space at EOA */
+        if(H5F_free(udata->f, udata->dxpl_id, udata->alloc_type, (*sect)->sect_info.addr, (*sect)->sect_info.size) < 0)
             HGOTO_ERROR(H5E_RESOURCE, H5E_CANTFREE, FAIL, "driver free request failed")
     } /* end if */
     else {
@@ -427,7 +611,7 @@ H5MF_sect_simple_shrink(H5FS_section_info_t **_sect, void *_udata)
     /* Check for freeing section */
     if(udata->shrink != H5MF_SHRINK_SECT_ABSORB_AGGR) {
         /* Free section */
-        if(H5MF_sect_simple_free((H5FS_section_info_t *)*sect) < 0)
+        if(H5MF_sect_free((H5FS_section_info_t *)*sect) < 0)
             HGOTO_ERROR(H5E_RESOURCE, H5E_CANTRELEASE, FAIL, "can't free simple section node")
 
         /* Mark section as freed, for free space manager */
@@ -438,100 +622,474 @@ done:
     FUNC_LEAVE_NOAPI(ret_value)
 } /* H5MF_sect_simple_shrink() */
 
+/* 
+ * "small" section callbacks
+ */
+
+
+/*-------------------------------------------------------------------------
+ * Function:    H5MF_sect_small_add
+ *
+ * Purpose:     Perform actions on a small "meta" action before adding it to the free space manager:
+ *              1) Drop the section if it is at page end and its size <= page end threshold
+ *              2) Adjust section size to include page end threshold if 
+ *                 (section size + threshold) is at page end
+ *
+ * Return:      Success:        non-negative
+ *              Failure:        negative
+ *
+ * Programmer:  Vailin Choi; Dec 2012
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+H5MF_sect_small_add(H5FS_section_info_t **_sect, unsigned *flags, void *_udata)
+{
+    H5MF_free_section_t **sect = (H5MF_free_section_t **)_sect;   /* Fractal heap free section */
+    H5MF_sect_ud_t *udata = (H5MF_sect_ud_t *)_udata;   /* User data for callback */
+    haddr_t sect_end;
+    hsize_t rem, prem;
+    herr_t ret_value = SUCCEED;         /* Return value */
+
+    FUNC_ENTER_NOAPI_NOINIT
+
+#ifdef H5MF_ALLOC_DEBUG_MORE
+HDfprintf(stderr, "%s: Entering, section {%a, %Hu}\n", FUNC, (*sect)->sect_info.addr, (*sect)->sect_info.size);
+#endif /* H5MF_ALLOC_DEBUG_MORE */
+
+    /* Do not adjust the section raw data or global heap data */
+    if(udata->alloc_type == H5FD_MEM_DRAW || udata->alloc_type == H5FD_MEM_GHEAP)
+        HGOTO_DONE(ret_value);
+
+    sect_end = (*sect)->sect_info.addr + (*sect)->sect_info.size;
+    rem = sect_end % udata->f->shared->fs_page_size;
+    prem = udata->f->shared->fs_page_size - rem;
+
+    /* Drop the section if it is at page end and its size is <= pgend threshold */
+    if(!rem && (*sect)->sect_info.size <= H5F_PGEND_META_THRES(udata->f) && (*flags & H5FS_ADD_RETURNED_SPACE)) {
+        if(H5MF_sect_free((H5FS_section_info_t *)(*sect)) < 0)
+            HGOTO_ERROR(H5E_RESOURCE, H5E_CANTRELEASE, FAIL, "can't free section node")
+        *sect = NULL;
+        *flags &= (unsigned)~H5FS_ADD_RETURNED_SPACE;
+        *flags |= H5FS_PAGE_END_NO_ADD;
+#ifdef H5MF_ALLOC_DEBUG_MORE
+HDfprintf(stderr, "%s: section is dropped\n", FUNC);
+#endif /* H5MF_ALLOC_DEBUG_MORE */
+    } /* end if */
+    /* Adjust the section if it is not at page end but its size + pgend threshold is at page end */
+    else
+        if(prem <= H5F_PGEND_META_THRES(udata->f)) {
+            (*sect)->sect_info.size += prem;
+#ifdef H5MF_ALLOC_DEBUG_MORE
+HDfprintf(stderr, "%s: section is adjusted {%a, %Hu}\n", FUNC, (*sect)->sect_info.addr, (*sect)->sect_info.size);
+#endif /* H5MF_ALLOC_DEBUG_MORE */
+        } /* end if */
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* H5MF_sect_small_add() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:	H5MF_sect_small_can_shrink
+ *
+ * Purpose:	Can this section shrink the container?
+ *
+ * Note: 	A small section is allowed to shrink only at closing.
+ *
+ * Return:	Success:	non-negative (TRUE/FALSE)
+ *          Failure:	negative
+ *
+ * Programmer:	Vailin Choi; Dec 2012
+ *
+ *-------------------------------------------------------------------------
+ */
+static htri_t
+H5MF_sect_small_can_shrink(const H5FS_section_info_t *_sect, void *_udata)
+{
+    const H5MF_free_section_t *sect = (const H5MF_free_section_t *)_sect;   /* File free section */
+    H5MF_sect_ud_t *udata = (H5MF_sect_ud_t *)_udata;   /* User data for callback */
+    haddr_t eoa;                /* End of address space in the file */
+    haddr_t end;                /* End of section to extend */
+    htri_t ret_value = FALSE;	/* Return value */
+
+    FUNC_ENTER_NOAPI_NOINIT
+
+    /* Check arguments. */
+    HDassert(sect);
+    HDassert(udata);
+    HDassert(udata->f);
+
+    /* Retrieve the end of the file's address space */
+    if(HADDR_UNDEF == (eoa = H5FD_get_eoa(udata->f->shared->lf, udata->alloc_type)))
+        HGOTO_ERROR(H5E_RESOURCE, H5E_CANTGET, FAIL, "driver get_eoa request failed")
+
+    /* Compute address of end of section to check */
+    end = sect->sect_info.addr + sect->sect_info.size;
+
+    /* Check if the section is exactly at the end of the allocated space in the file */
+    if(H5F_addr_eq(end, eoa) && sect->sect_info.size == udata->f->shared->fs_page_size) {
+        udata->shrink = H5MF_SHRINK_EOA;
+
+#ifdef H5MF_ALLOC_DEBUG_MORE
+HDfprintf(stderr, "%s: section {%a, %Hu}, shrinks file, eoa = %a\n", FUNC, sect->sect_info.addr, sect->sect_info.size, eoa);
+#endif /* H5MF_ALLOC_DEBUG_MORE */
+
+        /* Indicate shrinking can occur */
+        HGOTO_DONE(TRUE)
+    } /* end if */
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* H5MF_sect_small_can_shrink() */
+
 
 /*-------------------------------------------------------------------------
- * Function:	H5MF_sect_simple_free
+ * Function:	H5MF_sect_small_shrink
  *
- * Purpose:	Free a 'single' section node
+ * Purpose:	Shrink container with section
  *
  * Return:	Success:	non-negative
- *		Failure:	negative
+ *          Failure:	negative 
+ * 
+ * Programmer:	Vailin Choi; Dec 2012
  *
- * Programmer:	Quincey Koziol
- *              Tuesday, January  8, 2008
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+H5MF_sect_small_shrink(H5FS_section_info_t **_sect, void *_udata)
+{
+    H5MF_free_section_t **sect = (H5MF_free_section_t **)_sect;   /* File free section */
+    H5MF_sect_ud_t *udata = (H5MF_sect_ud_t *)_udata;   /* User data for callback */
+    herr_t ret_value = SUCCEED;         /* Return value */
+
+    FUNC_ENTER_NOAPI_NOINIT
+
+    /* Check arguments. */
+    HDassert(sect);
+    HDassert((*sect)->sect_info.type == H5MF_FSPACE_SECT_SMALL);
+    HDassert(udata);
+    HDassert(udata->f);
+    HDassert(udata->shrink == H5MF_SHRINK_EOA);
+    HDassert(H5F_INTENT(udata->f) & H5F_ACC_RDWR);
+
+    /* Release section's space at EOA */
+    if(H5F_free(udata->f, udata->dxpl_id, udata->alloc_type, (*sect)->sect_info.addr, (*sect)->sect_info.size) < 0)
+        HGOTO_ERROR(H5E_RESOURCE, H5E_CANTFREE, FAIL, "driver free request failed")
+
+    /* Free section */
+    if(H5MF_sect_free((H5FS_section_info_t *)*sect) < 0)
+        HGOTO_ERROR(H5E_RESOURCE, H5E_CANTRELEASE, FAIL, "can't free simple section node")
+
+    /* Mark section as freed, for free space manager */
+    *sect = NULL;
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* H5MF_sect_small_shrink() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:	H5MF_sect_small_can_merge
+ *
+ * Purpose:	Can two sections of this type merge?
+ *
+ * Note: Second section must be "after" first section
+ *       The "merged" section cannot cross page boundary.
+ *
+ * Return:	Success:	non-negative (TRUE/FALSE)
+ *          Failure:	negative
+ *
+ * Programmer:	Vailin Choi; Dec 2012
  *
  *-------------------------------------------------------------------------
  */
-herr_t
-H5MF_sect_simple_free(H5FS_section_info_t *_sect)
+static htri_t
+H5MF_sect_small_can_merge(const H5FS_section_info_t *_sect1,
+    const H5FS_section_info_t *_sect2, void *_udata)
 {
-    H5MF_free_section_t *sect = (H5MF_free_section_t *)_sect;   /* File free section */
+    const H5MF_free_section_t *sect1 = (const H5MF_free_section_t *)_sect1;   /* File free section */
+    const H5MF_free_section_t *sect2 = (const H5MF_free_section_t *)_sect2;   /* File free section */
+    H5MF_sect_ud_t *udata = (H5MF_sect_ud_t *)_udata;   /* User data for callback */
+    htri_t ret_value = FALSE;                   	/* Return value */
 
     FUNC_ENTER_NOAPI_NOINIT_NOERR
 
     /* Check arguments. */
-    HDassert(sect);
+    HDassert(sect1);
+    HDassert(sect2);
+    HDassert(sect1->sect_info.type == sect2->sect_info.type);   /* Checks "MERGE_SYM" flag */
+    HDassert(H5F_addr_lt(sect1->sect_info.addr, sect2->sect_info.addr));
 
-    /* Release the section */
-    sect = H5FL_FREE(H5MF_free_section_t, sect);
+    /* Check if second section adjoins first section */
+    ret_value = H5F_addr_eq(sect1->sect_info.addr + sect1->sect_info.size, sect2->sect_info.addr);
+    if(ret_value > 0)
+        /* If they are on different pages, couldn't merge */
+        if((sect1->sect_info.addr / udata->f->shared->fs_page_size) != (((sect2->sect_info.addr + sect2->sect_info.size - 1) / udata->f->shared->fs_page_size)))
+	    ret_value = FALSE;
 
-    FUNC_LEAVE_NOAPI(SUCCEED)
-}   /* H5MF_sect_simple_free() */
+#ifdef H5MF_ALLOC_DEBUG_MORE
+HDfprintf(stderr, "%s: Leaving: ret_value = %t\n", FUNC, ret_value);
+#endif /* H5MF_ALLOC_DEBUG_MORE */
+
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* H5MF_sect_small_can_merge() */
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5MF_sect_simple_valid
+ * Function:	H5MF_sect_small_merge
  *
- * Purpose:	Check the validity of a section
+ * Purpose:	Merge two sections of this type
+ *
+ * Note: Second section always merges into first node.
+ *       If the size of the "merged" section is equal to file space page size,
+ *       free the section.
  *
  * Return:	Success:	non-negative
  *		Failure:	negative
  *
- * Programmer:	Quincey Koziol
- *              Tuesday, January  8, 2008
+ * Programmer:	Vailin Choi; Dec 2012
  *
  *-------------------------------------------------------------------------
  */
 static herr_t
-H5MF_sect_simple_valid(const H5FS_section_class_t H5_ATTR_UNUSED *cls,
-    const H5FS_section_info_t
-#ifdef NDEBUG
-    H5_ATTR_UNUSED
-#endif /* NDEBUG */
-    *_sect, hid_t H5_ATTR_UNUSED dxpl_id)
+H5MF_sect_small_merge(H5FS_section_info_t **_sect1, H5FS_section_info_t *_sect2,
+    void *_udata)
 {
-#ifndef NDEBUG
-    const H5MF_free_section_t *sect = (const H5MF_free_section_t *)_sect;   /* File free section */
-#endif /* NDEBUG */
+    H5MF_free_section_t **sect1 = (H5MF_free_section_t **)_sect1;   /* File free section */
+    H5MF_free_section_t *sect2 = (H5MF_free_section_t *)_sect2;   /* File free section */
+    H5MF_sect_ud_t *udata = (H5MF_sect_ud_t *)_udata;   /* User data for callback */
+    herr_t ret_value = SUCCEED;         		/* Return value */
+
+    FUNC_ENTER_NOAPI_NOINIT
+
+    /* Check arguments. */
+    HDassert(sect1);
+    HDassert((*sect1)->sect_info.type == H5MF_FSPACE_SECT_SMALL);
+    HDassert(sect2);
+    HDassert(sect2->sect_info.type == H5MF_FSPACE_SECT_SMALL);
+    HDassert(H5F_addr_eq((*sect1)->sect_info.addr + (*sect1)->sect_info.size, sect2->sect_info.addr));
+
+    /* Add second section's size to first section */
+    (*sect1)->sect_info.size += sect2->sect_info.size;
+
+    if((*sect1)->sect_info.size == udata->f->shared->fs_page_size) {
+        if(H5MF_xfree(udata->f, udata->alloc_type, udata->dxpl_id, (*sect1)->sect_info.addr, (*sect1)->sect_info.size) < 0)
+            HGOTO_ERROR(H5E_RESOURCE, H5E_CANTFREE, FAIL, "can't free merged section")
+
+        /* Need to free possible metadata page in the PB cache */
+        /* This is in response to the data corruption bug from fheap.c with page buffering + page strategy */
+        /* Note: Large metadata page bypasses the PB cache */
+        /* Note: Update of raw data page (large or small sized) is handled by the PB cache */
+        if(udata->f->shared->page_buf != NULL && udata->alloc_type != H5FD_MEM_DRAW)
+            if(H5PB_remove_entry(udata->f, (*sect1)->sect_info.addr) < 0)
+                HGOTO_ERROR(H5E_RESOURCE, H5E_CANTFREE, FAIL, "can't free merged section")
+
+        if(H5MF_sect_free((H5FS_section_info_t *)(*sect1)) < 0)
+            HGOTO_ERROR(H5E_RESOURCE, H5E_CANTRELEASE, FAIL, "can't free section node")
+        *sect1 = NULL;
+    } /* end if */
+
+    /* Get rid of second section */
+    if(H5MF_sect_free((H5FS_section_info_t *)sect2) < 0)
+        HGOTO_ERROR(H5E_RESOURCE, H5E_CANTRELEASE, FAIL, "can't free section node")
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* H5MF_sect_small_merge() */
+
+/* 
+ * "Large" section callbacks
+ */
+
+
+/*-------------------------------------------------------------------------
+ * Function:	H5MF_sect_large_can_merge (same as H5MF_sect_simple_can_merge)
+ *
+ * Purpose:	Can two sections of this type merge?
+ *
+ * Note: Second section must be "after" first section
+ *
+ * Return:	Success:	non-negative (TRUE/FALSE)
+ *          Failure:	negative
+ *
+ * Programmer:	Vailin Choi; Dec 2012
+ *
+ *-------------------------------------------------------------------------
+ */
+static htri_t
+H5MF_sect_large_can_merge(const H5FS_section_info_t *_sect1,
+    const H5FS_section_info_t *_sect2, void H5_ATTR_UNUSED *_udata)
+{
+    const H5MF_free_section_t *sect1 = (const H5MF_free_section_t *)_sect1;   	/* File free section */
+    const H5MF_free_section_t *sect2 = (const H5MF_free_section_t *)_sect2;   	/* File free section */
+    htri_t ret_value = FALSE;           /* Return value */
 
     FUNC_ENTER_NOAPI_NOINIT_NOERR
 
     /* Check arguments. */
+    HDassert(sect1);
+    HDassert(sect2);
+    HDassert(sect1->sect_info.type == sect2->sect_info.type);   /* Checks "MERGE_SYM" flag */
+    HDassert(H5F_addr_lt(sect1->sect_info.addr, sect2->sect_info.addr));
+
+    ret_value = H5F_addr_eq(sect1->sect_info.addr + sect1->sect_info.size, sect2->sect_info.addr);
+
+#ifdef H5MF_ALLOC_DEBUG_MORE
+HDfprintf(stderr, "%s: Leaving: ret_value = %t\n", FUNC, ret_value);
+#endif /* H5MF_ALLOC_DEBUG_MORE */
+
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* H5MF_sect_large_can_merge() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:	H5MF_sect_large_merge (same as H5MF_sect_simple_merge)
+ *
+ * Purpose:	Merge two sections of this type
+ *
+ * Note: Second section always merges into first node
+ *
+ * Return:	Success:	non-negative
+ *          Failure:	negative
+ *
+ * Programmer:	Vailin Choi; Dec 2012
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+H5MF_sect_large_merge(H5FS_section_info_t **_sect1, H5FS_section_info_t *_sect2,
+    void H5_ATTR_UNUSED *_udata)
+{
+    H5MF_free_section_t **sect1 = (H5MF_free_section_t **)_sect1;   /* File free section */
+    H5MF_free_section_t *sect2 = (H5MF_free_section_t *)_sect2;   /* File free section */
+    herr_t ret_value = SUCCEED;         /* Return value */
+
+    FUNC_ENTER_NOAPI_NOINIT
+
+    /* Check arguments. */
+    HDassert(sect1);
+    HDassert((*sect1)->sect_info.type == H5MF_FSPACE_SECT_LARGE);
+    HDassert(sect2);
+    HDassert(sect2->sect_info.type == H5MF_FSPACE_SECT_LARGE);
+    HDassert(H5F_addr_eq((*sect1)->sect_info.addr + (*sect1)->sect_info.size, sect2->sect_info.addr));
+
+    /* Add second section's size to first section */
+    (*sect1)->sect_info.size += sect2->sect_info.size;
+
+    /* Get rid of second section */
+    if(H5MF_sect_free((H5FS_section_info_t *)sect2) < 0)
+        HGOTO_ERROR(H5E_RESOURCE, H5E_CANTRELEASE, FAIL, "can't free section node")
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* H5MF_sect_large_merge() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:	H5MF_sect_large_can_shrink
+ *
+ * Purpose:	Can this section shrink the container?
+ *
+ * Return:	Success:	non-negative (TRUE/FALSE)
+ *          Failure:	negative
+ *
+ * Programmer:	Vailin Choi; Dec 2012
+ *
+ *-------------------------------------------------------------------------
+ */
+static htri_t
+H5MF_sect_large_can_shrink(const H5FS_section_info_t *_sect, void *_udata)
+{
+    const H5MF_free_section_t *sect = (const H5MF_free_section_t *)_sect;   /* File free section */
+    H5MF_sect_ud_t *udata = (H5MF_sect_ud_t *)_udata;   /* User data for callback */
+    haddr_t eoa;                /* End of address space in the file */
+    haddr_t end;                /* End of section to extend */
+    htri_t ret_value = FALSE;	/* Return value */
+
+    FUNC_ENTER_NOAPI_NOINIT
+
+    /* Check arguments. */
     HDassert(sect);
+    HDassert(sect->sect_info.type == H5MF_FSPACE_SECT_LARGE);
+    HDassert(udata);
+    HDassert(udata->f);
 
-    FUNC_LEAVE_NOAPI(SUCCEED)
-}   /* H5MF_sect_simple_valid() */
+    /* Retrieve the end of the file's address space */
+    if(HADDR_UNDEF == (eoa = H5FD_get_eoa(udata->f->shared->lf, udata->alloc_type)))
+        HGOTO_ERROR(H5E_RESOURCE, H5E_CANTGET, FAIL, "driver get_eoa request failed")
+
+    /* Compute address of end of section to check */
+    end = sect->sect_info.addr + sect->sect_info.size;
+
+    /* Check if the section is exactly at the end of the allocated space in the file */
+    if(H5F_addr_eq(end, eoa) && sect->sect_info.size >= udata->f->shared->fs_page_size) {
+        /* Set the shrinking type */
+        udata->shrink = H5MF_SHRINK_EOA;
+#ifdef H5MF_ALLOC_DEBUG_MORE
+HDfprintf(stderr, "%s: section {%a, %Hu}, shrinks file, eoa = %a\n", FUNC, sect->sect_info.addr, sect->sect_info.size, eoa);
+#endif /* H5MF_ALLOC_DEBUG_MORE */
 
+        /* Indicate shrinking can occur */
+        HGOTO_DONE(TRUE)
+    } /* end if */
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* H5MF_sect_large_can_shrink() */
 
+
 /*-------------------------------------------------------------------------
- * Function:	H5MF_sect_simple_split
+ * Function:	H5MF_sect_large_shrink
  *
- * Purpose:	Split SECT into 2 sections: fragment for alignment & the aligned section
- *		SECT's addr and size are updated to point to the aligned section
+ * Purpose:     Shrink a large-sized section
  *
- * Return:	Success:	the fragment for aligning sect
- *		Failure:	null
+ * Return:      Success:	non-negative
+ *              Failure:	negative
  *
- * Programmer:	Vailin Choi, July 29, 2008
+ * Programmer:	Vailin Choi; Dec 2012
  *
  *-------------------------------------------------------------------------
  */
-static H5FS_section_info_t *
-H5MF_sect_simple_split(H5FS_section_info_t *sect, hsize_t frag_size)
+static herr_t
+H5MF_sect_large_shrink(H5FS_section_info_t **_sect, void *_udata)
 {
-    H5MF_free_section_t *ret_value = NULL;      /* Return value */
+    H5MF_free_section_t **sect = (H5MF_free_section_t **)_sect; /* File free section */
+    H5MF_sect_ud_t *udata = (H5MF_sect_ud_t *)_udata;           /* User data for callback */
+    hsize_t frag_size = 0;              /* Fragment size */
+    herr_t ret_value = SUCCEED;         /* Return value */
 
     FUNC_ENTER_NOAPI_NOINIT
 
-    /* Allocate space for new section */
-    if(NULL == (ret_value = H5MF_sect_simple_new(sect->addr, frag_size)))
-        HGOTO_ERROR(H5E_RESOURCE, H5E_CANTALLOC, NULL, "can't initialize free space section")
+    /* Check arguments. */
+    HDassert(sect);
+    HDassert((*sect)->sect_info.type == H5MF_FSPACE_SECT_LARGE);
+    HDassert(udata);
+    HDassert(udata->f);
+    HDassert(udata->shrink == H5MF_SHRINK_EOA);
+    HDassert(H5F_INTENT(udata->f) & H5F_ACC_RDWR);
+    HDassert(H5F_PAGED_AGGR(udata->f));
 
-    /* Set new section's info */
-    sect->addr += frag_size;
-    sect->size -= frag_size;
+    /* Calculate possible mis-aligned fragment */
+    H5MF_EOA_MISALIGN(udata->f, (*sect)->sect_info.addr, udata->f->shared->fs_page_size, frag_size);
+
+    /* Free full pages from EOA */
+    /* Retain partial page in the free-space manager so as to keep EOA at page boundary */
+    if(H5F_free(udata->f, udata->dxpl_id, udata->alloc_type, (*sect)->sect_info.addr+frag_size, (*sect)->sect_info.size-frag_size) < 0)
+        HGOTO_ERROR(H5E_RESOURCE, H5E_CANTFREE, FAIL, "driver free request failed")
+
+    if(frag_size) /* Adjust section size for the partial page */
+        (*sect)->sect_info.size = frag_size;
+    else {
+        /* Free section */
+        if(H5MF_sect_free((H5FS_section_info_t *)*sect) < 0)
+            HGOTO_ERROR(H5E_RESOURCE, H5E_CANTRELEASE, FAIL, "can't free simple section node")
+
+        /* Mark section as freed, for free space manager */
+        *sect = NULL;
+    } /* end else */
 
 done:
-    FUNC_LEAVE_NOAPI((H5FS_section_info_t *)ret_value)
-} /* end H5MF_sect_simple_split() */
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* H5MF_sect_large_shrink() */
 
diff --git a/src/H5Oalloc.c b/src/H5Oalloc.c
index 4f98cfa..40c9c38 100644
--- a/src/H5Oalloc.c
+++ b/src/H5Oalloc.c
@@ -2023,6 +2023,7 @@ H5O_merge_null(H5F_t *f, hid_t dxpl_id, H5O_t *oh)
                         /* Second message has been merged, delete it */
                         if(merged_msg) {
                             H5O_chunk_proxy_t *curr_chk_proxy;        /* Chunk that message is in */
+                            htri_t result;
 
                             /* Release any information/memory for second message */
                             H5O_msg_free_mesg(curr_msg2);
@@ -2050,6 +2051,13 @@ H5O_merge_null(H5F_t *f, hid_t dxpl_id, H5O_t *oh)
                             /* (Don't bother reducing size of message array for now -QAK) */
                             oh->nmesgs--;
 
+                            /* The merge null message might span the entire chunk: scan for empty chunk to remove */
+                            if((result = H5O_remove_empty_chunks(f, dxpl_id, oh)) < 0)
+                                HGOTO_ERROR(H5E_OHDR, H5E_CANTPACK, FAIL, "can't remove empty chunk")
+                            else if(result > 0)
+                                /* Get out of loop */
+                                break;
+
                             /* If the merged message is too large, shrink the chunk */
                             if(curr_msg->raw_size >= H5O_MESG_MAX_SIZE)
                                 if(H5O_alloc_shrink_chunk(f, dxpl_id, oh, curr_msg->chunkno) < 0)
diff --git a/src/H5Ocache_image.c b/src/H5Ocache_image.c
index 65f6aa2..bea99a2 100644
--- a/src/H5Ocache_image.c
+++ b/src/H5Ocache_image.c
@@ -33,6 +33,7 @@
 
 #include "H5private.h"          /* Generic Functions                     */
 #include "H5Eprivate.h"         /* Error handling                        */
+#include "H5Fprivate.h"		/* Files				*/
 #include "H5FLprivate.h"        /* Free Lists                            */
 #include "H5Opkg.h"             /* Object headers                        */
 #include "H5MFprivate.h"        /* File space management                 */
@@ -290,9 +291,50 @@ H5O__mdci_delete(H5F_t *f, hid_t dxpl_id, H5O_t *open_oh, void *_mesg)
     HDassert(mesg);
 
     /* Free file space for cache image */
-    if(H5F_addr_defined(mesg->addr))
-        if(H5MF_xfree(f, H5FD_MEM_SUPER, dxpl_id, mesg->addr, mesg->size) < 0)
-            HGOTO_ERROR(H5E_OHDR, H5E_CANTFREE, FAIL, "unable to free file space for cache image block")
+    if(H5F_addr_defined(mesg->addr)) {
+        /* The space for the cache image block was allocated directly
+         * from the VFD layer at the end of file.  As this was the
+         * last file space allocation before shutdown, the cache image
+         * should still be the last item in the file.
+         *
+         * If the hack to work around the self referential free space
+         * manager issue is in use, file space for the non-empty self
+         * referential free space managers was also allocated from VFD
+         * layer at the end of file.  Since these allocations directly
+         * preceeded the cache image allocation they should be directly
+         * adjacent to the cache image block at the end of file.
+         *
+         * In this case, just call H5MF_tidy_self_referential_fsm_hack().
+         *
+         * That routine will float the self referential free space
+         * managers, and reduce the eoa to its value just prior to
+         * allocation of space for same.  Since the cache image appears
+         * just after the self referential free space managers, this
+         * will release the file space for the cache image as well.
+         *
+         * Note that in this case, there must not have been any file
+         * space allocations / deallocations prior to the free of the
+         * cache image.  Verify this to the extent possible.
+         *
+         * If the hack to work around the persistant self referential
+         * free space manager issue is NOT in use, just call H5MF_xfree()
+         * to release the cache iamge.  In principle, we should be able
+         * to just reduce the EOA to the base address of the cache
+         * image block, as there shouldn't be any file space allocation
+         * before the first metadata cache access.  However, given
+         * time constraints, I don't want to go there now.
+         */
+        if(H5F_FIRST_ALLOC_DEALLOC(f)) {
+            HDassert(HADDR_UNDEF !=H5F_EOA_PRE_FSM_FSALLOC(f));
+            HDassert(H5F_addr_ge(mesg->addr, H5F_EOA_PRE_FSM_FSALLOC(f)));
+            if(H5MF_tidy_self_referential_fsm_hack(f, dxpl_id) < 0)
+                HGOTO_ERROR(H5E_OHDR, H5E_CANTFREE, FAIL, "tidy of self referential fsm hack failed")
+        } /* end if */
+        else {
+            if(H5MF_xfree(f, H5FD_MEM_SUPER, dxpl_id, mesg->addr, mesg->size) < 0)
+                HGOTO_ERROR(H5E_OHDR, H5E_CANTFREE, FAIL, "unable to free file space for cache image block")
+        } /* end else */
+    } /* end if */
 
 done:
     FUNC_LEAVE_NOAPI(ret_value)
diff --git a/src/H5Ofsinfo.c b/src/H5Ofsinfo.c
index 938d319..37ec627 100644
--- a/src/H5Ofsinfo.c
+++ b/src/H5Ofsinfo.c
@@ -23,12 +23,13 @@
  *
  *-------------------------------------------------------------------------
  */
-
+#define H5F_FRIEND              /*suppress error about including H5Fpkg   */
 #include "H5Omodule.h"          /* This source code file is part of the H5O module */
 
 
 #include "H5private.h"		/* Generic Functions	*/
 #include "H5Eprivate.h"		/* Error handling	*/
+#include "H5Fpkg.h"             /* File access          */
 #include "H5FLprivate.h"	/* Free lists          	*/
 #include "H5Opkg.h"             /* Object headers	*/
 
@@ -66,7 +67,8 @@ const H5O_msg_class_t H5O_MSG_FSINFO[1] = {{
 }};
 
 /* Current version of free-space manager info information */
-#define H5O_FSINFO_VERSION 	0
+#define H5O_FSINFO_VERSION_0 	0
+#define H5O_FSINFO_VERSION_1 	1
 
 /* Declare a free list to manage the H5O_fsinfo_t struct */
 H5FL_DEFINE_STATIC(H5O_fsinfo_t);
@@ -85,12 +87,13 @@ H5FL_DEFINE_STATIC(H5O_fsinfo_t);
  *-------------------------------------------------------------------------
  */
 static void *
-H5O_fsinfo_decode(H5F_t *f, hid_t H5_ATTR_UNUSED dxpl_id, H5O_t H5_ATTR_UNUSED *open_oh,
+H5O_fsinfo_decode(H5F_t *f, hid_t dxpl_id, H5O_t H5_ATTR_UNUSED *open_oh,
     unsigned H5_ATTR_UNUSED mesg_flags, unsigned H5_ATTR_UNUSED *ioflags, const uint8_t *p)
 {
-    H5O_fsinfo_t	*fsinfo = NULL; /* free-space manager info */
-    H5FD_mem_t 		type;		/* Memory type for iteration */
-    void                *ret_value = NULL;      /* Return value */
+    H5O_fsinfo_t    *fsinfo = NULL;     /* File space info message */
+    H5F_mem_page_t  ptype;              /* Memory type for iteration */
+    unsigned        vers;               /* message version */
+    void            *ret_value = NULL;  /* Return value */
 
     FUNC_ENTER_NOAPI_NOINIT
 
@@ -98,26 +101,83 @@ H5O_fsinfo_decode(H5F_t *f, hid_t H5_ATTR_UNUSED dxpl_id, H5O_t H5_ATTR_UNUSED *
     HDassert(f);
     HDassert(p);
 
-    /* Version of message */
-    if(*p++ != H5O_FSINFO_VERSION)
-        HGOTO_ERROR(H5E_OHDR, H5E_CANTLOAD, NULL, "bad version number for message")
-
     /* Allocate space for message */
     if(NULL == (fsinfo = H5FL_CALLOC(H5O_fsinfo_t)))
 	HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, NULL, "memory allocation failed")
 
-    fsinfo->strategy = (H5F_file_space_type_t)*p++;	/* file space strategy */
-    H5F_DECODE_LENGTH(f, p, fsinfo->threshold);	/* free space section size threshold */
+    for(ptype = H5F_MEM_PAGE_SUPER; ptype < H5F_MEM_PAGE_NTYPES; H5_INC_ENUM(H5F_mem_page_t, ptype))
+        fsinfo->fs_addr[ptype - 1] = HADDR_UNDEF;
 
-    /* Addresses of free space managers: only exist for H5F_FILE_SPACE_ALL_PERSIST */
-    if(fsinfo->strategy == H5F_FILE_SPACE_ALL_PERSIST) {
-	for(type = H5FD_MEM_SUPER; type < H5FD_MEM_NTYPES; H5_INC_ENUM(H5FD_mem_t, type))
-	    H5F_addr_decode(f, &p, &(fsinfo->fs_addr[type-1]));
-    } /* end if */
-    else {
-	for(type = H5FD_MEM_SUPER; type < H5FD_MEM_NTYPES; H5_INC_ENUM(H5FD_mem_t, type))
-	    fsinfo->fs_addr[type-1] = HADDR_UNDEF;
-    } /* end else */
+    /* Version of message */
+    vers = *p++;
+
+    if(vers == H5O_FSINFO_VERSION_0) {
+        H5F_file_space_type_t strategy;     /* Strategy */
+        hsize_t threshold;                  /* Threshold */
+        H5FD_mem_t type;                    /* Memory type for iteration */
+
+        fsinfo->persist = H5F_FREE_SPACE_PERSIST_DEF;
+        fsinfo->threshold = H5F_FREE_SPACE_THRESHOLD_DEF;
+        fsinfo->page_size = H5F_FILE_SPACE_PAGE_SIZE_DEF;
+        fsinfo->pgend_meta_thres = H5F_FILE_SPACE_PGEND_META_THRES;
+        fsinfo->eoa_pre_fsm_fsalloc = HADDR_UNDEF;
+
+        strategy = (H5F_file_space_type_t)*p++; /* File space strategy */
+        H5F_DECODE_LENGTH(f, p, threshold);     /* Free-space section threshold */
+
+        /* Map version 0 (deprecated) to version 1 message */
+        switch(strategy) {
+
+            case H5F_FILE_SPACE_ALL_PERSIST:
+                fsinfo->strategy = H5F_FSPACE_STRATEGY_FSM_AGGR;
+                fsinfo->persist = TRUE;
+                fsinfo->threshold = threshold;
+                if(HADDR_UNDEF == (fsinfo->eoa_pre_fsm_fsalloc = H5F_get_eoa(f, H5FD_MEM_DEFAULT)) )
+                    HGOTO_ERROR(H5E_FILE, H5E_CANTGET, NULL, "unable to get file size")
+                for(type = H5FD_MEM_SUPER; type < H5FD_MEM_NTYPES; H5_INC_ENUM(H5FD_mem_t, type))
+                    H5F_addr_decode(f, &p, &(fsinfo->fs_addr[type-1]));
+                break;
+
+            case H5F_FILE_SPACE_ALL:
+                fsinfo->strategy = H5F_FSPACE_STRATEGY_FSM_AGGR;
+                fsinfo->threshold = threshold;
+                break;
+
+            case H5F_FILE_SPACE_AGGR_VFD:
+                fsinfo->strategy = H5F_FSPACE_STRATEGY_AGGR;
+                break;
+
+            case H5F_FILE_SPACE_VFD:
+                fsinfo->strategy = H5F_FSPACE_STRATEGY_NONE;
+                break;
+
+            case H5F_FILE_SPACE_NTYPES:
+            case H5F_FILE_SPACE_DEFAULT:
+            default:
+                HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, NULL, "invalid file space strategy")
+        } /* end switch */
+
+        fsinfo->mapped = TRUE;
+       
+    } else {
+        HDassert(vers == H5O_FSINFO_VERSION_1);
+
+        fsinfo->strategy = (H5F_fspace_strategy_t)*p++; /* File space strategy */
+        fsinfo->persist = *p++;                         /* Free-space persist or not */
+        H5F_DECODE_LENGTH(f, p, fsinfo->threshold);     /* Free-space section threshold */
+
+        H5F_DECODE_LENGTH(f, p, fsinfo->page_size); /* File space page size */
+        UINT16DECODE(p, fsinfo->pgend_meta_thres);  /* Page end metdata threshold */
+        H5F_addr_decode(f, &p, &(fsinfo->eoa_pre_fsm_fsalloc)); /* EOA before free-space header and section info */
+
+        /* Decode addresses of free space managers, if persisting */
+        if(fsinfo->persist) {
+            for(ptype = H5F_MEM_PAGE_SUPER; ptype < H5F_MEM_PAGE_NTYPES; H5_INC_ENUM(H5F_mem_page_t, ptype))
+                H5F_addr_decode(f, &p, &(fsinfo->fs_addr[ptype - 1]));
+        } /* end if */
+
+        fsinfo->mapped = FALSE;
+    }
 
     /* Set return value */
     ret_value = fsinfo;
@@ -145,7 +205,7 @@ static herr_t
 H5O_fsinfo_encode(H5F_t *f, hbool_t H5_ATTR_UNUSED disable_shared, uint8_t *p, const void *_mesg)
 {
     const H5O_fsinfo_t  *fsinfo = (const H5O_fsinfo_t *)_mesg;
-    H5FD_mem_t 		type;	/* Memory type for iteration */
+    H5F_mem_page_t 	ptype;  /* Memory type for iteration */
 
     FUNC_ENTER_NOAPI_NOINIT_NOERR
 
@@ -154,14 +214,20 @@ H5O_fsinfo_encode(H5F_t *f, hbool_t H5_ATTR_UNUSED disable_shared, uint8_t *p, c
     HDassert(p);
     HDassert(fsinfo);
 
-    *p++ = H5O_FSINFO_VERSION;	/* message version */
-    *p++ = fsinfo->strategy;	/* file space strategy */
-    H5F_ENCODE_LENGTH(f, p, fsinfo->threshold); /* free-space section size threshold */
+    *p++ = H5O_FSINFO_VERSION_1;	/* message version */
+    *p++ = fsinfo->strategy;	    /* File space strategy */
+    *p++ = (unsigned char)fsinfo->persist;	/* Free-space persist or not */
+    H5F_ENCODE_LENGTH(f, p, fsinfo->threshold); /* Free-space section size threshold */
+
+    H5F_ENCODE_LENGTH(f, p, fsinfo->page_size);	/* File space page size */
+    UINT16ENCODE(p, fsinfo->pgend_meta_thres);	/* Page end metadata threshold */
+    H5F_addr_encode(f, &p, fsinfo->eoa_pre_fsm_fsalloc);    /* EOA before free-space header and section info */
 
-    /* Addresses of free space managers: only exist for H5F_FILE_SPACE_ALL_PERSIST */
-    if(fsinfo->strategy == H5F_FILE_SPACE_ALL_PERSIST) {
-	for(type = H5FD_MEM_SUPER; type < H5FD_MEM_NTYPES; H5_INC_ENUM(H5FD_mem_t, type))
-	    H5F_addr_encode(f, &p, fsinfo->fs_addr[type-1]);
+    /* Store addresses of free-space managers, if persisting */
+    if(fsinfo->persist) {
+        /* Addresses of free-space managers */
+        for(ptype = H5F_MEM_PAGE_SUPER; ptype < H5F_MEM_PAGE_NTYPES; H5_INC_ENUM(H5F_mem_page_t, ptype))
+            H5F_addr_encode(f, &p, fsinfo->fs_addr[ptype - 1]);
     } /* end if */
 
     FUNC_LEAVE_NOAPI(SUCCEED)
@@ -224,19 +290,19 @@ static size_t
 H5O_fsinfo_size(const H5F_t *f, hbool_t H5_ATTR_UNUSED disable_shared, const void *_mesg)
 {
     const H5O_fsinfo_t   *fsinfo = (const H5O_fsinfo_t *)_mesg;
-    size_t fs_addr_size = 0;
     size_t ret_value = 0;       /* Return value */
 
     FUNC_ENTER_NOAPI_NOINIT_NOERR
 
-
-    /* Addresses of free-space managers exist only for H5F_FILE_SPACE_ALL_PERSIST type */
-    if(H5F_FILE_SPACE_ALL_PERSIST == fsinfo->strategy)
-	fs_addr_size = (H5FD_MEM_NTYPES - 1) * (size_t)H5F_SIZEOF_ADDR(f);
-
-    ret_value = 2                       /* Version & strategy */
-		+ (size_t)H5F_SIZEOF_SIZE(f)	/* Threshold */
-                + fs_addr_size;		/* Addresses of free-space managers */
+    ret_value = 3                       /* Version, strategy & persist */
+		+ (size_t)H5F_SIZEOF_SIZE(f)    /* Free-space section threshold */
+		+ (size_t)H5F_SIZEOF_SIZE(f)    /* File space page size */
+		+ 2                             /* Page end meta threshold */
+		+ (size_t)H5F_SIZEOF_ADDR(f);
+    
+    /* Free-space manager addresses */
+    if(fsinfo->persist)
+        ret_value += (H5F_MEM_PAGE_NTYPES - 1) * (size_t)H5F_SIZEOF_ADDR(f);
 
     FUNC_LEAVE_NOAPI(ret_value)
 } /* end H5O_fsinfo_size() */
@@ -282,7 +348,7 @@ H5O_fsinfo_debug(H5F_t H5_ATTR_UNUSED *f, hid_t H5_ATTR_UNUSED dxpl_id, const vo
 	       int indent, int fwidth)
 {
     const H5O_fsinfo_t	*fsinfo = (const H5O_fsinfo_t *) _mesg;
-    H5FD_mem_t 		type;	/* Memory type for iteration */
+    H5F_mem_page_t  ptype;      /* Free-space types for iteration */
 
     FUNC_ENTER_NOAPI_NOINIT_NOERR
 
@@ -293,16 +359,48 @@ H5O_fsinfo_debug(H5F_t H5_ATTR_UNUSED *f, hid_t H5_ATTR_UNUSED dxpl_id, const vo
     HDassert(indent >= 0);
     HDassert(fwidth >= 0);
 
-    HDfprintf(stream, "%*s%-*s %u\n", indent, "", fwidth,
-              "File space strategy:", fsinfo->strategy);
+    HDfprintf(stream, "%*s%-*s ", indent, "", fwidth, "File space strategy:");
+    switch(fsinfo->strategy) {
+        case H5F_FSPACE_STRATEGY_FSM_AGGR:
+            HDfprintf(stream, "%s\n", "H5F_FSPACE_STRATEGY_FSM_AGGR");
+            break;
+
+        case H5F_FSPACE_STRATEGY_PAGE:
+            HDfprintf(stream, "%s\n", "H5F_FSPACE_STRATEGY_PAGE");
+            break;
+
+        case H5F_FSPACE_STRATEGY_AGGR:
+            HDfprintf(stream, "%s\n", "H5F_FSPACE_STRATEGY_AGGR");
+            break;
+
+        case H5F_FSPACE_STRATEGY_NONE:
+            HDfprintf(stream, "%s\n", "H5F_FSPACE_STRATEGY_NONE");
+            break;
+
+        case H5F_FSPACE_STRATEGY_NTYPES:
+        default:
+            HDfprintf(stream, "%s\n", "unknown");
+    } /* end switch */
+
+    HDfprintf(stream, "%*s%-*s %t\n", indent, "", fwidth,
+              "Free-space persist:", fsinfo->persist);
 
     HDfprintf(stream, "%*s%-*s %Hu\n", indent, "", fwidth,
-              "Free space section threshold:", fsinfo->threshold);
+              "Free-space section threshold:", fsinfo->threshold);
+
+    HDfprintf(stream, "%*s%-*s %Hu\n", indent, "", fwidth,
+              "File space page size:", fsinfo->page_size);
+
+    HDfprintf(stream, "%*s%-*s %u\n", indent, "", fwidth,
+              "Page end metadata threshold:", fsinfo->pgend_meta_thres);
+
+    HDfprintf(stream, "%*s%-*s %a\n", indent, "", fwidth,
+              "eoa_pre_fsm_fsalloc:", fsinfo->eoa_pre_fsm_fsalloc);
 
-    if(fsinfo->strategy == H5F_FILE_SPACE_ALL_PERSIST) {
-	for(type = H5FD_MEM_SUPER; type < H5FD_MEM_NTYPES; H5_INC_ENUM(H5FD_mem_t, type))
-	    HDfprintf(stream, "%*s%-*s %a\n", indent, "", fwidth,
-		"Free space manager address:", fsinfo->fs_addr[type-1]);
+    if(fsinfo->persist) {
+        for(ptype = H5F_MEM_PAGE_SUPER; ptype < H5F_MEM_PAGE_NTYPES; H5_INC_ENUM(H5F_mem_page_t, ptype))
+            HDfprintf(stream, "%*s%-*s %a\n", indent, "", fwidth,
+                "Free space manager address:", fsinfo->fs_addr[ptype-1]);
     } /* end if */
 
     FUNC_LEAVE_NOAPI(SUCCEED)
diff --git a/src/H5Omessage.c b/src/H5Omessage.c
index 376c888..7e6463a 100644
--- a/src/H5Omessage.c
+++ b/src/H5Omessage.c
@@ -2253,3 +2253,55 @@ done:
     FUNC_LEAVE_NOAPI(ret_value)
 } /* end H5O_flush_msgs() */
 
+
+/*-------------------------------------------------------------------------
+ * Function:	H5O_msg_get_flags
+ *
+ * Purpose:	Queries a message's message flags in the object header
+ *
+ * Return:	Non-negative on success/Negative on failure
+ *
+ * Programmer:	Vailin; Jan 2013
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5O_msg_get_flags(const H5O_loc_t *loc, unsigned type_id, hid_t dxpl_id, uint8_t *flags)
+{
+    H5O_t *oh = NULL;                   /* Object header to use */
+    const H5O_msg_class_t *type;        /* Actual H5O class type for the ID */
+    H5O_mesg_t *idx_msg;                /* Pointer to message to modify */
+    unsigned idx;                       /* Index of message to modify */
+    herr_t ret_value = SUCCEED;         /* Return value */
+
+    FUNC_ENTER_NOAPI(FAIL)
+
+    /* check args */
+    HDassert(loc);
+    HDassert(loc->file);
+    HDassert(H5F_addr_defined(loc->addr));
+    HDassert(type_id < NELMTS(H5O_msg_class_g));
+    type = H5O_msg_class_g[type_id];    /* map the type ID to the actual type object */
+    HDassert(type);
+
+    /* Get the object header */
+    if(NULL == (oh = H5O_protect(loc, dxpl_id, H5AC__READ_ONLY_FLAG, FALSE)))
+        HGOTO_ERROR(H5E_OHDR, H5E_CANTPROTECT, FAIL, "unable to protect object header")
+
+    /* Locate message of correct type */
+    for(idx = 0, idx_msg = &oh->mesg[0]; idx < oh->nmesgs; idx++, idx_msg++)
+        if(type == idx_msg->type)
+            break;
+
+    if(idx == oh->nmesgs)
+        HGOTO_ERROR(H5E_OHDR, H5E_NOTFOUND, FAIL, "message type not found")
+
+    /* Set return value */
+    *flags = idx_msg->flags;
+
+done:
+    if(oh && H5O_unprotect(loc, dxpl_id, oh, H5AC__NO_FLAGS_SET) < 0)
+        HDONE_ERROR(H5E_OHDR, H5E_CANTUNPROTECT, FAIL, "unable to release object header")
+
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5O_msg_get_flags() */
diff --git a/src/H5Oprivate.h b/src/H5Oprivate.h
index 71c512c..f0fbe72 100644
--- a/src/H5Oprivate.h
+++ b/src/H5Oprivate.h
@@ -791,9 +791,16 @@ typedef unsigned H5O_unknown_t;         /* Original message type ID */
  * (Data structure in memory)
  */
 typedef struct H5O_fsinfo_t {
-    H5F_file_space_type_t strategy;	/* File space strategy */
-    hsize_t		  threshold;	/* Free space section threshold */
-    haddr_t     	  fs_addr[H5FD_MEM_NTYPES-1]; /* Addresses of free space managers */
+    H5F_fspace_strategy_t   strategy;       /* File space strategy */
+    hbool_t persist;                        /* Persisting free-space or not */
+    hsize_t threshold;                      /* Free-space section threshold */
+    hsize_t page_size;                      /* For paged aggregation: file space page size */
+    size_t pgend_meta_thres;                /* For paged aggregation: page end metadata threshold */
+    haddr_t eoa_pre_fsm_fsalloc;            /* For paged aggregation: the eoa before free-space headers & sinfo */
+    haddr_t fs_addr[H5F_MEM_PAGE_NTYPES - 1];   /* 13 addresses of free-space managers */
+                                                /* For non-paged aggregation: only 6 addresses are used */
+    hbool_t mapped;                             /* Not stored */
+                                                /* Indicate the message is mapped from version 0 to version 1 */
 } H5O_fsinfo_t;
 
 /*
@@ -920,6 +927,7 @@ H5_DLL void* H5O_msg_decode(H5F_t *f, hid_t dxpl_id, H5O_t *open_oh,
     unsigned type_id, const unsigned char *buf);
 H5_DLL herr_t H5O_msg_delete(H5F_t *f, hid_t dxpl_id, H5O_t *open_oh,
     unsigned type_id, void *mesg);
+H5_DLL herr_t H5O_msg_get_flags(const H5O_loc_t *loc, unsigned type_id, hid_t dxpl_id, uint8_t *flags);
 
 /* Object metadata flush/refresh routines */
 H5_DLL herr_t H5O_flush_common(H5O_loc_t *oloc, hid_t obj_id, hid_t dxpl_id);
diff --git a/src/H5PB.c b/src/H5PB.c
new file mode 100644
index 0000000..c67ae59
--- /dev/null
+++ b/src/H5PB.c
@@ -0,0 +1,1533 @@
+/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
+ * Copyright by The HDF Group.                                               *
+ * Copyright by the Board of Trustees of the University of Illinois.         *
+ * All rights reserved.                                                      *
+ *                                                                           *
+ * This file is part of HDF5.  The full HDF5 copyright notice, including     *
+ * terms governing use, modification, and redistribution, is contained in    *
+ * the files COPYING and Copyright.html.  COPYING can be found at the root   *
+ * of the source code distribution tree; Copyright.html can be found at the  *
+ * root level of an installed copy of the electronic HDF5 document set and   *
+ * is linked from the top-level documents page.  It can also be found at     *
+ * http://hdfgroup.org/HDF5/doc/Copyright.html.  If you do not have          *
+ * access to either file, you may request a copy from help@hdfgroup.org.     *
+ * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
+
+/*-------------------------------------------------------------------------
+ *
+ * Created:             H5PB.c
+ *
+ * Purpose:             Page Buffer routines.
+ *
+ *-------------------------------------------------------------------------
+ */
+
+/****************/
+/* Module Setup */
+/****************/
+
+#define H5F_FRIEND		/*suppress error about including H5Fpkg	  */
+#include "H5PBmodule.h"         /* This source code file is part of the H5PB module */
+
+
+/***********/
+/* Headers */
+/***********/
+#include "H5private.h"		/* Generic Functions			*/
+#include "H5Eprivate.h"		/* Error handling		  	*/
+#include "H5Fpkg.h"		/* Files				*/
+#include "H5FDprivate.h"	/* File drivers				*/
+#include "H5Iprivate.h"		/* IDs			  		*/
+#include "H5PBpkg.h"            /* File access				*/
+#include "H5SLprivate.h"	/* Skip List				*/
+
+
+/****************/
+/* Local Macros */
+/****************/
+#define H5PB__PREPEND(page_ptr, head_ptr, tail_ptr, len) {              \
+        if((head_ptr) == NULL) {                                        \
+            (head_ptr) = (page_ptr);                                    \
+            (tail_ptr) = (page_ptr);                                    \
+        } /* end if */                                                  \
+        else {                                                          \
+            (head_ptr)->prev = (page_ptr);                              \
+            (page_ptr)->next = (head_ptr);                              \
+            (head_ptr) = (page_ptr);                                    \
+        } /* end else */                                                \
+        (len)++;                                                        \
+} /* H5PB__PREPEND() */
+
+#define H5PB__REMOVE(page_ptr, head_ptr, tail_ptr, len) {               \
+        if((head_ptr) == (page_ptr)) {                                  \
+            (head_ptr) = (page_ptr)->next;                              \
+            if((head_ptr) != NULL)                                      \
+                (head_ptr)->prev = NULL;                                \
+        } /* end if */                                                  \
+        else                                                            \
+            (page_ptr)->prev->next = (page_ptr)->next;                  \
+        if((tail_ptr) == (page_ptr)) {                                  \
+            (tail_ptr) = (page_ptr)->prev;                              \
+            if((tail_ptr) != NULL)                                      \
+                (tail_ptr)->next = NULL;                                \
+        } /* end if */                                                  \
+        else                                                            \
+            (page_ptr)->next->prev = (page_ptr)->prev;                  \
+        page_ptr->next = NULL;                                          \
+        page_ptr->prev = NULL;                                          \
+        (len)--;                                                        \
+}
+
+#define H5PB__INSERT_LRU(page_buf, page_ptr) {                          \
+        HDassert(page_buf);                                             \
+        HDassert(page_ptr);                                             \
+        /* insert the entry at the head of the list. */                 \
+        H5PB__PREPEND((page_ptr), (page_buf)->LRU_head_ptr,             \
+                      (page_buf)->LRU_tail_ptr, (page_buf)->LRU_list_len) \
+}
+
+#define H5PB__REMOVE_LRU(page_buf, page_ptr) {                          \
+        HDassert(page_buf);                                             \
+        HDassert(page_ptr);                                             \
+        /* remove the entry from the list. */                           \
+        H5PB__REMOVE((page_ptr), (page_buf)->LRU_head_ptr,              \
+                     (page_buf)->LRU_tail_ptr, (page_buf)->LRU_list_len) \
+}
+
+#define H5PB__MOVE_TO_TOP_LRU(page_buf, page_ptr) {                     \
+        HDassert(page_buf);                                             \
+        HDassert(page_ptr);                                             \
+        /* Remove entry and insert at the head of the list. */          \
+        H5PB__REMOVE((page_ptr), (page_buf)->LRU_head_ptr,              \
+                     (page_buf)->LRU_tail_ptr, (page_buf)->LRU_list_len) \
+        H5PB__PREPEND((page_ptr), (page_buf)->LRU_head_ptr,             \
+                       (page_buf)->LRU_tail_ptr, (page_buf)->LRU_list_len) \
+}
+
+
+/******************/
+/* Local Typedefs */
+/******************/
+
+/* Iteration context for destroying page buffer */
+typedef struct {
+    H5PB_t *page_buf;
+    hbool_t actual_slist;
+} H5PB_ud1_t;
+
+
+/********************/
+/* Package Typedefs */
+/********************/
+
+
+/********************/
+/* Local Prototypes */
+/********************/
+static herr_t H5PB__insert_entry(H5PB_t *page_buf, H5PB_entry_t *page_entry);
+static htri_t H5PB__make_space(const H5F_io_info2_t *fio_info, H5PB_t *page_buf, H5FD_mem_t inserted_type);
+static herr_t H5PB__write_entry(const H5F_io_info2_t *fio_info, H5PB_entry_t *page_entry);
+
+
+/*********************/
+/* Package Variables */
+/*********************/
+
+/* Package initialization variable */
+hbool_t H5_PKG_INIT_VAR = FALSE;
+
+
+/*****************************/
+/* Library Private Variables */
+/*****************************/
+
+
+/*******************/
+/* Local Variables */
+/*******************/
+/* Declare a free list to manage the H5PB_t struct */
+H5FL_DEFINE_STATIC(H5PB_t);
+
+/* Declare a free list to manage the H5PB_entry_t struct */
+H5FL_DEFINE_STATIC(H5PB_entry_t);
+
+
+
+/*-------------------------------------------------------------------------
+ * Function:	H5PB_reset_stats
+ *
+ * Purpose:     This function was created without documentation.
+ *              What follows is my best understanding of Mohamad's intent.
+ *
+ *              Reset statistics collected for the page buffer layer.
+ *
+ * Return:      Non-negative on success/Negative on failure
+ *
+ * Programmer:	Mohamad Chaarawi
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t 
+H5PB_reset_stats(H5PB_t *page_buf)
+{
+    FUNC_ENTER_NOAPI_NOERR
+
+    /* Sanity checks */
+    HDassert(page_buf);
+
+    page_buf->accesses[0] = 0;
+    page_buf->accesses[1] = 0;
+    page_buf->hits[0] = 0;
+    page_buf->hits[1] = 0;
+    page_buf->misses[0] = 0;
+    page_buf->misses[1] = 0;
+    page_buf->evictions[0] = 0;
+    page_buf->evictions[1] = 0;
+    page_buf->bypasses[0] = 0;
+    page_buf->bypasses[1] = 0;
+
+    FUNC_LEAVE_NOAPI(SUCCEED)
+}  /* H5PB_reset_stats() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:	H5PB_get_stats
+ *
+ * Purpose:     This function was created without documentation.
+ *              What follows is my best understanding of Mohamad's intent.
+ *
+ *              Retrieve statistics collected about page accesses for the page buffer layer.
+ *              --accesses: the number of metadata and raw data accesses to the page buffer layer
+ *              --hits: the number of metadata and raw data hits in the page buffer layer
+ *              --misses: the number of metadata and raw data misses in the page buffer layer
+ *              --evictions: the number of metadata and raw data evictions from the page buffer layer
+ *              --bypasses: the number of metadata and raw data accesses that bypass the page buffer layer
+ *
+ * Return:	    Non-negative on success/Negative on failure
+ *
+ * Programmer:	Mohamad Chaarawi
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t 
+H5PB_get_stats(const H5PB_t *page_buf, unsigned accesses[2], unsigned hits[2],
+    unsigned misses[2], unsigned evictions[2], unsigned bypasses[2])
+{
+    FUNC_ENTER_NOAPI_NOERR
+
+    /* Sanity checks */
+    HDassert(page_buf);
+
+    accesses[0] = page_buf->accesses[0];
+    accesses[1] = page_buf->accesses[1];
+    hits[0] = page_buf->hits[0];
+    hits[1] = page_buf->hits[1];
+    misses[0] = page_buf->misses[0];
+    misses[1] = page_buf->misses[1];
+    evictions[0] = page_buf->evictions[0];
+    evictions[1] = page_buf->evictions[1];
+    bypasses[0] = page_buf->bypasses[0];
+    bypasses[1] = page_buf->bypasses[1];
+
+    FUNC_LEAVE_NOAPI(SUCCEED)
+}  /* H5PB_get_stats */
+
+
+/*-------------------------------------------------------------------------
+ * Function:	H5PB_print_stats()
+ *
+ * Purpose:     This function was created without documentation.
+ *              What follows is my best understanding of Mohamad's intent.
+ *
+ *              Print out statistics collected for the page buffer layer.
+ *
+ * Return:	    Non-negative on success/Negative on failure
+ *
+ * Programmer:	Mohamad Chaarawi
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5PB_print_stats(const H5PB_t *page_buf)
+{
+    FUNC_ENTER_NOAPI_NOINIT_NOERR
+
+    HDassert(page_buf);
+
+    printf("PAGE BUFFER STATISTICS:\n");
+
+    printf("******* METADATA\n");
+    printf("\t Total Accesses: %u\n", page_buf->accesses[0]);
+    printf("\t Hits: %u\n", page_buf->hits[0]);
+    printf("\t Misses: %u\n", page_buf->misses[0]);
+    printf("\t Evictions: %u\n", page_buf->evictions[0]);
+    printf("\t Bypasses: %u\n", page_buf->bypasses[0]);
+    printf("\t Hit Rate = %f%%\n", ((double)page_buf->hits[0]/(page_buf->accesses[0] - page_buf->bypasses[0]))*100);
+    printf("*****************\n\n");
+
+    printf("******* RAWDATA\n");
+    printf("\t Total Accesses: %u\n", page_buf->accesses[1]);
+    printf("\t Hits: %u\n", page_buf->hits[1]);
+    printf("\t Misses: %u\n", page_buf->misses[1]);
+    printf("\t Evictions: %u\n", page_buf->evictions[1]);
+    printf("\t Bypasses: %u\n", page_buf->bypasses[1]);
+    printf("\t Hit Rate = %f%%\n", ((double)page_buf->hits[1]/(page_buf->accesses[1]-page_buf->bypasses[0]))*100);
+    printf("*****************\n\n");
+
+    FUNC_LEAVE_NOAPI(SUCCEED)
+} /* H5PB_print_stats */
+
+
+/*-------------------------------------------------------------------------
+ * Function:	H5PB_create
+ *
+ * Purpose:	Create and setup the PB on the file.
+ *
+ * Return:	Non-negative on success/Negative on failure
+ *
+ * Programmer:	Mohamad Chaarawi
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5PB_create(H5F_t *f, size_t size, unsigned page_buf_min_meta_perc, unsigned page_buf_min_raw_perc)
+{
+    H5PB_t *page_buf = NULL;
+    herr_t ret_value = SUCCEED;    /* Return value */
+
+    FUNC_ENTER_NOAPI(FAIL)
+
+    /* Sanity checks */
+    HDassert(f);
+    HDassert(f->shared);
+
+    /* Check args */
+    if(f->shared->fs_strategy != H5F_FSPACE_STRATEGY_PAGE)
+        HGOTO_ERROR(H5E_FILE, H5E_CANTINIT, FAIL, "Enabling Page Buffering requires PAGE file space strategy")
+    /* round down the size if it is larger than the page size */
+    else if(size > f->shared->fs_page_size) {
+        hsize_t temp_size;
+
+        temp_size = (size / f->shared->fs_page_size) * f->shared->fs_page_size;
+        H5_CHECKED_ASSIGN(size, size_t, temp_size, hsize_t);
+    } /* end if */
+    else if(0 != size % f->shared->fs_page_size)
+        HGOTO_ERROR(H5E_PAGEBUF, H5E_CANTINIT, FAIL, "Page Buffer size must be >= to the page size")
+
+    /* Allocate the new page buffering structure */
+    if(NULL == (page_buf = H5FL_CALLOC(H5PB_t)))
+	HGOTO_ERROR(H5E_PAGEBUF, H5E_NOSPACE, FAIL, "memory allocation failed")
+
+    page_buf->max_size = size;
+    H5_CHECKED_ASSIGN(page_buf->page_size, size_t, f->shared->fs_page_size, hsize_t);
+    page_buf->min_meta_perc = page_buf_min_meta_perc;
+    page_buf->min_raw_perc = page_buf_min_raw_perc;
+
+    /* Calculate the minimum page count for metadata and raw data
+     * based on the fractions provided 
+     */
+    page_buf->min_meta_count = (unsigned)((size * page_buf_min_meta_perc) / (f->shared->fs_page_size * 100));
+    page_buf->min_raw_count = (unsigned)((size * page_buf_min_raw_perc) / (f->shared->fs_page_size * 100));
+
+    if(NULL == (page_buf->slist_ptr = H5SL_create(H5SL_TYPE_HADDR, NULL)))
+        HGOTO_ERROR(H5E_PAGEBUF, H5E_CANTCREATE, FAIL, "can't create skip list")
+    if(NULL == (page_buf->mf_slist_ptr = H5SL_create(H5SL_TYPE_HADDR, NULL)))
+        HGOTO_ERROR(H5E_PAGEBUF, H5E_CANTCREATE, FAIL, "can't create skip list")
+
+    if(NULL == (page_buf->page_fac = H5FL_fac_init(page_buf->page_size)))
+        HGOTO_ERROR(H5E_PAGEBUF, H5E_CANTINIT, FAIL, "can't create page factory")
+
+    f->shared->page_buf = page_buf;
+
+done:
+    if(ret_value < 0) {
+        if(page_buf != NULL) {
+            if(page_buf->slist_ptr != NULL)
+                H5SL_close(page_buf->slist_ptr);
+            if(page_buf->mf_slist_ptr != NULL)
+                H5SL_close(page_buf->mf_slist_ptr);
+            if(page_buf->page_fac != NULL)
+                H5FL_fac_term(page_buf->page_fac);
+            page_buf = H5FL_FREE(H5PB_t, page_buf);
+        } /* end if */
+    } /* end if */
+
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* H5PB_create */
+
+
+/*-------------------------------------------------------------------------
+ * Function:	H5PB__flush_cb
+ *
+ * Purpose:	Callback to flush PB skiplist entries.
+ *
+ * Return:	Non-negative on success/Negative on failure
+ *
+ * Programmer:	Mohamad Chaarawi
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+H5PB__flush_cb(void *item, void H5_ATTR_UNUSED *key, void *_op_data)
+{
+    H5PB_entry_t *page_entry = (H5PB_entry_t *)item;    /* Pointer to page entry node */
+    const H5F_io_info2_t *fio_info = (const H5F_io_info2_t *)_op_data;
+    herr_t  ret_value = SUCCEED;    /* Return value */
+
+    FUNC_ENTER_STATIC
+
+    /* Sanity checks */
+    HDassert(page_entry);
+    HDassert(fio_info);
+
+    /* Flush the page if it's dirty */
+    if(page_entry->is_dirty)
+        if(H5PB__write_entry(fio_info, page_entry) < 0)
+            HGOTO_ERROR(H5E_PAGEBUF, H5E_WRITEERROR, FAIL, "file write failed")
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* H5PB__flush_cb() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:	H5PB_flush
+ *
+ * Purpose:	Flush/Free all the PB entries to the file.
+ *
+ * Return:	Non-negative on success/Negative on failure
+ *
+ * Programmer:	Mohamad Chaarawi
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5PB_flush(const H5F_io_info2_t *fio_info)
+{
+    herr_t  ret_value = SUCCEED;    /* Return value */
+
+    FUNC_ENTER_NOAPI(FAIL)
+
+    /* Sanity check */
+    HDassert(fio_info);
+    HDassert(fio_info->f);
+    HDassert(fio_info->meta_dxpl);
+    HDassert(fio_info->raw_dxpl);
+
+    /* Flush all the entries in the PB skiplist, if we have write access on the file */
+    if(fio_info->f->shared->page_buf && (H5F_ACC_RDWR & H5F_INTENT(fio_info->f))) {
+        H5PB_t *page_buf = fio_info->f->shared->page_buf;
+
+        /* Iterate over all entries in page buffer skip list */
+        if(H5SL_iterate(page_buf->slist_ptr, H5PB__flush_cb, (void *)fio_info))
+            HGOTO_ERROR(H5E_PAGEBUF, H5E_BADITER, FAIL, "can't flush page buffer skip list")
+    } /* end if */
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* H5PB_flush */
+
+
+/*-------------------------------------------------------------------------
+ * Function:	H5PB__dest_cb
+ *
+ * Purpose:	Callback to free PB skiplist entries.
+ *
+ * Return:	Non-negative on success/Negative on failure
+ *
+ * Programmer:	Mohamad Chaarawi
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+H5PB__dest_cb(void *item, void H5_ATTR_UNUSED *key, void *_op_data)
+{
+    H5PB_entry_t *page_entry = (H5PB_entry_t *)item;       /* Pointer to page entry node */
+    H5PB_ud1_t *op_data = (H5PB_ud1_t *)_op_data;
+
+    FUNC_ENTER_STATIC_NOERR
+
+    /* Sanity checking */
+    HDassert(page_entry);
+    HDassert(op_data);
+    HDassert(op_data->page_buf);
+
+    /* Remove entry from LRU list */
+    if(op_data->actual_slist) {
+        H5PB__REMOVE_LRU(op_data->page_buf, page_entry)
+        page_entry->page_buf_ptr = H5FL_FAC_FREE(op_data->page_buf->page_fac, page_entry->page_buf_ptr);
+    } /* end if */
+
+    /* Free page entry */
+    page_entry = H5FL_FREE(H5PB_entry_t, page_entry);
+
+    FUNC_LEAVE_NOAPI(SUCCEED)
+} /* H5PB__dest_cb() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:	H5PB_dest
+ *
+ * Purpose:	destroy the PB on the file.
+ *
+ * Return:	Non-negative on success/Negative on failure
+ *
+ * Programmer:	Mohamad Chaarawi
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5PB_dest(H5F_t *f)
+{
+    herr_t  ret_value = SUCCEED;        /* Return value */
+
+    FUNC_ENTER_NOAPI(FAIL)
+
+    /* Sanity checks */
+    HDassert(f);
+
+    /* Destroy page buffer info, if there is any */
+    if(f->shared->page_buf) {
+        H5PB_t *page_buf = f->shared->page_buf;
+        H5PB_ud1_t op_data;                 /* Iteration context */
+
+        /* Set up context info */
+        op_data.page_buf = page_buf;
+
+        /* Destroy the skip list containing all the entries in the PB */
+        op_data.actual_slist = TRUE;
+        if(H5SL_destroy(page_buf->slist_ptr, H5PB__dest_cb, &op_data))
+            HGOTO_ERROR(H5E_PAGEBUF, H5E_CANTCLOSEOBJ, FAIL, "can't destroy page buffer skip list")
+
+        /* Destroy the skip list containing the new entries */
+        op_data.actual_slist = FALSE;
+        if(H5SL_destroy(page_buf->mf_slist_ptr, H5PB__dest_cb, &op_data))
+            HGOTO_ERROR(H5E_PAGEBUF, H5E_CANTCLOSEOBJ, FAIL, "can't destroy page buffer skip list")
+
+        /* Destroy the page factory */
+        if(H5FL_fac_term(page_buf->page_fac) < 0)
+            HGOTO_ERROR(H5E_PAGEBUF, H5E_CANTRELEASE, FAIL, "can't destroy page buffer page factory")
+
+#ifdef QAK
+H5PB_print_stats(page_buf);
+#endif /* QAK */
+
+        f->shared->page_buf = H5FL_FREE(H5PB_t, page_buf);
+    } /* end if */
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* H5PB_dest */
+
+
+/*-------------------------------------------------------------------------
+ * Function:	H5PB_add_new_page
+ *
+ * Purpose:	Add a new page to the new page skip list. This is called 
+ *              from the MF layer when a new page is allocated to 
+ *              indicate to the page buffer layer that a read of the page 
+ *              from the file is not necessary since it's an empty page.
+ *
+ * Return:	Non-negative on success/Negative on failure
+ *
+ * Programmer:	Mohamad Chaarawi
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t 
+H5PB_add_new_page(H5F_t *f, H5FD_mem_t type, haddr_t page_addr)
+{
+    H5PB_t *page_buf = f->shared->page_buf;
+    H5PB_entry_t *page_entry = NULL;    /* pointer to the corresponding page entry */
+    herr_t ret_value = SUCCEED;    /* Return value */
+
+    FUNC_ENTER_NOAPI(FAIL)
+
+    /* Sanity checks */
+    HDassert(page_buf);
+
+    /* If there is an existing page, this means that at some point the
+     * file free space manager freed and re-allocated a page at the same
+     * address.  No need to do anything here then...
+     */
+    /* MSC - to be safe, might want to dig in the MF layer and remove
+     * the page when it is freed from this list if it still exists and
+     * remove this check
+     */
+    if(NULL == H5SL_search(page_buf->mf_slist_ptr, &(page_addr))) {
+        /* Create the new PB entry */
+        if(NULL == (page_entry = H5FL_CALLOC(H5PB_entry_t)))
+            HGOTO_ERROR(H5E_PAGEBUF, H5E_NOSPACE, FAIL, "memory allocation failed")
+
+        /* Initialize page fields */
+        page_entry->addr = page_addr;
+        page_entry->type = (H5F_mem_page_t)type;
+        page_entry->is_dirty = FALSE;
+
+        /* Insert entry in skip list */
+        if(H5SL_insert(page_buf->mf_slist_ptr, page_entry, &(page_entry->addr)) < 0)
+            HGOTO_ERROR(H5E_PAGEBUF, H5E_BADVALUE, FAIL, "Can't insert entry in skip list")
+    } /* end if */
+
+done:
+    if(ret_value < 0)
+        if(page_entry)
+            page_entry = H5FL_FREE(H5PB_entry_t, page_entry);
+
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* H5PB_add_new_page */
+
+
+/*-------------------------------------------------------------------------
+ * Function:	H5PB_update_entry
+ *
+ * Purpose:	In PHDF5, entries that are written by other processes and just 
+ *              marked clean by this process have to have their corresponding 
+ *              pages updated if they exist in the page buffer. 
+ *              This routine checks and update the pages.
+ *
+ * Return:	Non-negative on success/Negative on failure
+ *
+ * Programmer:	Mohamad Chaarawi
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t 
+H5PB_update_entry(H5PB_t *page_buf, haddr_t addr, size_t size, const void *buf)
+{
+    H5PB_entry_t *page_entry;   /* Pointer to the corresponding page entry */
+    haddr_t page_addr;
+
+    FUNC_ENTER_NOAPI_NOERR
+
+    /* Sanity checks */
+    HDassert(page_buf);
+    HDassert(size <= page_buf->page_size);
+    HDassert(buf);
+
+    /* calculate the aligned address of the first page */
+    page_addr = (addr / page_buf->page_size) * page_buf->page_size;
+
+    /* search for the page and update if found */
+    page_entry = (H5PB_entry_t *)H5SL_search(page_buf->slist_ptr, (void *)(&page_addr));
+    if(page_entry) {
+        haddr_t offset;
+
+        HDassert(addr + size <= page_addr + page_buf->page_size);
+        offset = addr - page_addr;
+        HDmemcpy((uint8_t *)page_entry->page_buf_ptr + offset, buf, size);
+
+        /* move to top of LRU list */
+        H5PB__MOVE_TO_TOP_LRU(page_buf, page_entry)
+    } /* end if */
+
+    FUNC_LEAVE_NOAPI(SUCCEED)
+} /* H5PB_update_entry */
+
+
+/*-------------------------------------------------------------------------
+ * Function:    H5PB_remove_entry
+ *
+ * Purpose:     Remove possible metadata entry with ADDR from the PB cache.
+ *              This is in response to the data corruption bug from fheap.c 
+ *              with page buffering + page strategy.
+ *              Note: Large metadata page bypasses the PB cache.
+ *              Note: Update of raw data page (large or small sized) is handled by the PB cache.
+ *
+ * Return:      Non-negative on success/Negative on failure
+ *
+ * Programmer:  Vailin Choi; Feb 2017
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5PB_remove_entry(const H5F_t *f, haddr_t addr)
+{
+    H5PB_t *page_buf = f->shared->page_buf;
+    H5PB_entry_t *page_entry = NULL;        /* pointer to the page entry being searched */
+    herr_t ret_value = SUCCEED;             /* Return value */
+
+    FUNC_ENTER_NOAPI(FAIL)
+
+    /* Sanity checks */
+    HDassert(page_buf);
+
+    /* Search for address in the skip list */
+    page_entry = (H5PB_entry_t *)H5SL_search(page_buf->slist_ptr, (void *)(&addr));
+
+    /* If found, remove the entry from the PB cache */
+    if(page_entry) {
+        HDassert(page_entry->type != H5F_MEM_PAGE_DRAW);
+        if(NULL == H5SL_remove(page_buf->slist_ptr, &(page_entry->addr)))
+            HGOTO_ERROR(H5E_CACHE, H5E_BADVALUE, FAIL, "Page Entry is not in skip list")
+
+        /* Remove from LRU list */
+        H5PB__REMOVE_LRU(page_buf, page_entry)
+        HDassert(H5SL_count(page_buf->slist_ptr) == page_buf->LRU_list_len);
+
+        page_buf->meta_count--;
+
+        page_entry->page_buf_ptr = H5FL_FAC_FREE(page_buf->page_fac, page_entry->page_buf_ptr);
+        page_entry = H5FL_FREE(H5PB_entry_t, page_entry);
+    } /* end if */
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* H5PB_remove_entry */
+
+
+/*-------------------------------------------------------------------------
+ * Function:	H5PB_read
+ *
+ * Purpose:	Reads in the data from the page containing it if it exists 
+ *              in the PB cache; otherwise reads in the page through the VFD.
+ *
+ * Return:	Non-negative on success/Negative on failure
+ *
+ * Programmer:	Mohamad Chaarawi
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5PB_read(const H5F_io_info2_t *fio_info, H5FD_mem_t type, haddr_t addr,
+    size_t size, void *buf/*out*/)
+{
+    H5PB_t *page_buf;                   /* Page buffering info for this file */
+    H5PB_entry_t *page_entry;           /* Pointer to the corresponding page entry */
+    H5FD_io_info_t fdio_info;           /* File driver I/O info */
+    haddr_t first_page_addr, last_page_addr;    /* Addresses of the first and last pages covered by I/O */
+    haddr_t offset;
+    haddr_t search_addr;                /* Address of current page */
+    hsize_t num_touched_pages;          /* Number of pages accessed */
+    size_t access_size;
+    hbool_t bypass_pb = FALSE;          /* Whether to bypass page buffering */
+    hsize_t i;                          /* Local index variable */
+    herr_t ret_value = SUCCEED;         /* Return value */
+
+    FUNC_ENTER_NOAPI(FAIL)
+
+    /* Sanity checks */
+    HDassert(fio_info);
+
+    /* Get pointer to page buffer info for this file */
+    page_buf = fio_info->f->shared->page_buf;
+
+#ifdef H5_HAVE_PARALLEL
+    if(H5F_HAS_FEATURE(fio_info->f, H5FD_FEAT_HAS_MPI)) {
+#if 1
+        bypass_pb = TRUE;
+#else
+        /* MSC - why this stopped working ? */
+        int mpi_size;
+
+        if((mpi_size = H5F_mpi_get_size(fio_info->f)) < 0)
+            HGOTO_ERROR(H5E_PAGEBUF, H5E_CANTGET, FAIL, "can't retrieve MPI communicator size")
+        if(1 != mpi_size)
+            bypass_pb = TRUE;
+#endif
+    } /* end if */
+#endif
+
+    /* If page buffering is disabled, or the I/O size is larger than that of a
+     * single page, or if this is a parallel raw data access, bypass page
+     * buffering.
+     */
+    if(NULL == page_buf || size >= page_buf->page_size ||
+           (bypass_pb && H5FD_MEM_DRAW == type)) {
+        if(H5F__accum_read(fio_info, type, addr, size, buf) < 0)
+            HGOTO_ERROR(H5E_PAGEBUF, H5E_READERROR, FAIL, "read through metadata accumulator failed")
+
+        /* Update statistics */
+        if(page_buf) {
+            if(type == H5FD_MEM_DRAW || type == H5FD_MEM_GHEAP)
+                page_buf->bypasses[1] ++;
+            else
+                page_buf->bypasses[0] ++;
+        } /* end if */
+
+        /* If page buffering is disabled, or if this is a large metadata access, 
+         * or if this is parallel raw data access, we are done here
+         */
+        if(NULL == page_buf || (size >= page_buf->page_size && H5FD_MEM_DRAW != type) ||
+                (bypass_pb && H5FD_MEM_DRAW == type))
+            HGOTO_DONE(SUCCEED)
+    } /* end if */
+
+    /* Update statistics */
+    if(page_buf) {
+        if(type == H5FD_MEM_DRAW || type == H5FD_MEM_GHEAP)
+            page_buf->accesses[1]++;
+        else
+            page_buf->accesses[0]++;
+    } /* end if */
+
+    /* Calculate the aligned address of the first page */
+    first_page_addr = (addr / page_buf->page_size) * page_buf->page_size;
+
+    /* For Raw data calculate the aligned address of the last page and
+     * the number of pages accessed if more than 1 page is accessed
+     */
+    if(H5FD_MEM_DRAW == type) {
+        last_page_addr = ((addr + size - 1) / page_buf->page_size) * page_buf->page_size;
+
+        /* How many pages does this write span */
+        num_touched_pages = (last_page_addr / page_buf->page_size + 1) - 
+                (first_page_addr / page_buf->page_size);
+        if(first_page_addr == last_page_addr) {
+            HDassert(1 == num_touched_pages);
+            last_page_addr = HADDR_UNDEF;
+        } /* end if */
+    } /* end if */
+    /* Otherwise set last page addr to HADDR_UNDEF */
+    else {
+        num_touched_pages = 1;
+        last_page_addr = HADDR_UNDEF;
+    } /* end else */
+
+    /* Translate to file driver I/O info object */
+    fdio_info.file = fio_info->f->shared->lf;
+    fdio_info.meta_dxpl = fio_info->meta_dxpl;
+    fdio_info.raw_dxpl = fio_info->raw_dxpl;
+
+    /* Copy raw data from dirty pages into the read buffer if the read
+       request spans pages in the page buffer*/
+    if(H5FD_MEM_DRAW == type && size >= page_buf->page_size) {
+        H5SL_node_t *node;
+
+        /* For each touched page in the page buffer, check if it
+         * exists in the page Buffer and is dirty. If it does, we
+         * update the buffer with what's in the page so we get the up
+         * to date data into the buffer after the big read from the file.
+         */
+        node = H5SL_find(page_buf->slist_ptr, (void *)(&first_page_addr));
+        for(i = 0; i < num_touched_pages; i++) {
+            search_addr = i*page_buf->page_size + first_page_addr;
+
+            /* if we still haven't located a starting page, search again */
+            if(!node && i!=0)
+                node = H5SL_find(page_buf->slist_ptr, (void *)(&search_addr));
+
+            /* if the current page is in the Page Buffer, do the updates */
+            if(node) {
+                page_entry = (H5PB_entry_t *)H5SL_item(node);
+
+                HDassert(page_entry);
+
+                /* If the current page address falls out of the access
+                   block, then there are no more pages to go over */
+                if(page_entry->addr >= addr + size)
+                    break;
+
+                HDassert(page_entry->addr == search_addr);
+
+                if(page_entry->is_dirty) {
+                    /* special handling for the first page if it is not a full page access */
+                    if(i == 0 && first_page_addr != addr) {
+                        offset = addr - first_page_addr;
+                        HDassert(page_buf->page_size > offset);
+
+                        HDmemcpy(buf, (uint8_t *)page_entry->page_buf_ptr + offset, 
+                                 page_buf->page_size - (size_t)offset);
+
+                        /* move to top of LRU list */
+                        H5PB__MOVE_TO_TOP_LRU(page_buf, page_entry)
+                    } /* end if */
+                    /* special handling for the last page if it is not a full page access */
+                    else if(num_touched_pages > 1 && i == num_touched_pages-1 && search_addr < addr+size) {
+                        offset = (num_touched_pages-2)*page_buf->page_size + 
+                            (page_buf->page_size - (addr - first_page_addr));
+
+                        HDmemcpy((uint8_t *)buf + offset, page_entry->page_buf_ptr,
+                                 (size_t)((addr + size) - last_page_addr));
+
+                        /* move to top of LRU list */
+                        H5PB__MOVE_TO_TOP_LRU(page_buf, page_entry)
+                    } /* end else-if */
+                    /* copy the entire fully accessed pages */
+                    else {
+                        offset = i*page_buf->page_size;
+
+                        HDmemcpy((uint8_t *)buf+(i*page_buf->page_size) , page_entry->page_buf_ptr, 
+                             page_buf->page_size);
+                    } /* end else */
+                } /* end if */
+                node = H5SL_next(node);
+            } /* end if */
+        } /* end for */
+    } /* end if */
+    else {
+        /* A raw data access could span 1 or 2 PB entries at this point so
+           we need to handle that */
+        HDassert(1 == num_touched_pages || 2 == num_touched_pages);
+        for(i = 0 ; i < num_touched_pages; i++) {
+            haddr_t buf_offset;
+
+            /* Calculate the aligned address of the page to search for it in the skip list */
+            search_addr = (0==i ? first_page_addr : last_page_addr);
+
+            /* Calculate the access size if the access spans more than 1 page */
+            if(1 == num_touched_pages)
+                access_size = size;
+            else
+                access_size = (0 == i ? (size_t)((first_page_addr + page_buf->page_size) - addr) : (size - access_size));
+
+            /* Lookup the page in the skip list */
+            page_entry = (H5PB_entry_t *)H5SL_search(page_buf->slist_ptr, (void *)(&search_addr));
+
+            /* if found */
+            if(page_entry) {
+                offset = (0 == i ? addr - page_entry->addr : 0);
+                buf_offset = (0 == i ? 0 : size - access_size);
+
+                /* copy the requested data from the page into the input buffer */
+                HDmemcpy((uint8_t *)buf + buf_offset, (uint8_t *)page_entry->page_buf_ptr + offset, access_size);
+
+                /* Update LRU */
+                H5PB__MOVE_TO_TOP_LRU(page_buf, page_entry)
+
+                /* Update statistics */
+                if(type == H5FD_MEM_DRAW || type == H5FD_MEM_GHEAP)
+                    page_buf->hits[1]++;
+                else
+                    page_buf->hits[0]++;
+            } /* end if */
+            /* if not found */ 
+            else {
+                void *new_page_buf = NULL;
+                size_t page_size = page_buf->page_size;
+                haddr_t eoa;
+
+                /* make space for new entry */
+                if((H5SL_count(page_buf->slist_ptr) * page_buf->page_size) >= page_buf->max_size) {
+                    htri_t can_make_space;
+
+                    /* check if we can make space in page buffer */
+                    if((can_make_space = H5PB__make_space(fio_info, page_buf, type)) < 0)
+                        HGOTO_ERROR(H5E_PAGEBUF, H5E_NOSPACE, FAIL, "make space in Page buffer Failed")
+
+                    /* if make_space returns 0, then we can't use the page
+                       buffer for this I/O and we need to bypass */
+                    if(0 == can_make_space) {
+                        /* make space can't return FALSE on second touched page since the first is of the same type */
+                        HDassert(0 == i);
+
+                        /* read entire block from VFD and return */
+                        if(H5FD_read(&fdio_info, type, addr, size, buf) < 0)
+                            HGOTO_ERROR(H5E_PAGEBUF, H5E_READERROR, FAIL, "driver read request failed")
+
+                        /* Break out of loop */
+                        break;
+                    } /* end if */
+                } /* end if */
+
+                /* Read page from VFD */
+                if(NULL == (new_page_buf = H5FL_FAC_MALLOC(page_buf->page_fac)))
+                    HGOTO_ERROR(H5E_PAGEBUF, H5E_CANTALLOC, FAIL, "memory allocation failed for page buffer entry")
+
+                /* Read page through the VFD layer, but make sure we don't read past the EOA. */
+
+                /* Retrieve the 'eoa' for the file */
+                if(HADDR_UNDEF == (eoa = H5F_get_eoa(fio_info->f, type)))
+                    HGOTO_ERROR(H5E_PAGEBUF, H5E_CANTGET, FAIL, "driver get_eoa request failed")
+
+                /* If the entire page falls outside the EOA, then fail */
+                if(search_addr > eoa)
+                    HGOTO_ERROR(H5E_PAGEBUF, H5E_BADVALUE, FAIL, "reading an entire page that is outside the file EOA")
+
+                /* Adjust the read size to not go beyond the EOA */
+                if(search_addr + page_size > eoa)
+                    page_size = (size_t)(eoa - search_addr);
+
+                /* Read page from VFD */
+                if(H5FD_read(&fdio_info, type, search_addr, page_size, new_page_buf) < 0)
+                    HGOTO_ERROR(H5E_PAGEBUF, H5E_READERROR, FAIL, "driver read request failed")
+
+                /* Copy the requested data from the page into the input buffer */
+                offset = (0 == i ? addr - search_addr : 0);
+                buf_offset = (0 == i ? 0 : size - access_size);
+                HDmemcpy((uint8_t *)buf + buf_offset, (uint8_t *)new_page_buf + offset, access_size);
+
+                /* Create the new PB entry */
+                if(NULL == (page_entry = H5FL_CALLOC(H5PB_entry_t)))
+                    HGOTO_ERROR(H5E_PAGEBUF, H5E_NOSPACE, FAIL, "memory allocation failed")
+
+                page_entry->page_buf_ptr = new_page_buf;
+                page_entry->addr = search_addr;
+                page_entry->type = (H5F_mem_page_t)type;
+                page_entry->is_dirty = FALSE;
+
+                /* Insert page into PB */
+                if(H5PB__insert_entry(page_buf, page_entry) < 0)
+                    HGOTO_ERROR(H5E_PAGEBUF, H5E_CANTSET, FAIL, "error inserting new page in page buffer")
+
+                /* Update statistics */
+                if(type == H5FD_MEM_DRAW || type == H5FD_MEM_GHEAP)
+                    page_buf->misses[1]++;
+                else
+                    page_buf->misses[0]++;
+            } /* end else */
+        } /* end for */
+    } /* end else */
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5PB_read() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:	H5PB_write
+ *
+ * Purpose: Write data into the Page Buffer. If the page exists in the
+ *          cache, update it; otherwise read it from disk, update it, and
+ *          insert into cache.
+ *
+ * Return:	Non-negative on success/Negative on failure
+ *
+ * Programmer:	Mohamad Chaarawi
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5PB_write(const H5F_io_info2_t *fio_info, H5FD_mem_t type, haddr_t addr,
+    size_t size, const void *buf)
+{
+    H5PB_t *page_buf;                   /* Page buffering info for this file */
+    H5PB_entry_t *page_entry;           /* Pointer to the corresponding page entry */
+    H5FD_io_info_t fdio_info;           /* File driver I/O info */
+    haddr_t first_page_addr, last_page_addr;    /* Addresses of the first and last pages covered by I/O */
+    haddr_t offset;
+    haddr_t search_addr;                /* Address of current page */
+    hsize_t num_touched_pages;          /* Number of pages accessed */
+    size_t access_size;
+    hbool_t bypass_pb = FALSE;          /* Whether to bypass page buffering */
+    hsize_t i;                          /* Local index variable */
+    herr_t  ret_value = SUCCEED;        /* Return value */
+
+    FUNC_ENTER_NOAPI(FAIL)
+
+    /* Sanity checks */
+    HDassert(fio_info);
+    HDassert(fio_info->f);
+
+    /* Get pointer to page buffer info for this file */
+    page_buf = fio_info->f->shared->page_buf;
+
+#ifdef H5_HAVE_PARALLEL
+    if(H5F_HAS_FEATURE(fio_info->f, H5FD_FEAT_HAS_MPI)) {
+#if 1
+        bypass_pb = TRUE;
+#else
+        /* MSC - why this stopped working ? */
+        int mpi_size;
+
+        if((mpi_size = H5F_mpi_get_size(fio_info->f)) < 0)
+            HGOTO_ERROR(H5E_PAGEBUF, H5E_CANTGET, FAIL, "can't retrieve MPI communicator size")
+        if(1 != mpi_size)
+            bypass_pb = TRUE;
+#endif
+    } /* end if */
+#endif
+
+    /* If page buffering is disabled, or the I/O size is larger than that of a
+     * single page, or if this is a parallel raw data access, bypass page
+     * buffering.
+     */
+    if(NULL == page_buf || size >= page_buf->page_size || bypass_pb) {
+        if(H5F__accum_write(fio_info, type, addr, size, buf) < 0)
+            HGOTO_ERROR(H5E_PAGEBUF, H5E_WRITEERROR, FAIL, "write through metadata accumulator failed")
+
+        /* Update statistics */
+        if(page_buf) {
+            if(type == H5FD_MEM_DRAW || type == H5FD_MEM_GHEAP)
+                page_buf->bypasses[1]++;
+            else
+                page_buf->bypasses[0]++;
+        } /* end if */
+
+        /* If page buffering is disabled, or if this is a large metadata access, 
+         * or if this is a parallel raw data access, we are done here
+         */
+        if(NULL == page_buf || (size >= page_buf->page_size && H5FD_MEM_DRAW != type) ||
+                (bypass_pb && H5FD_MEM_DRAW == type))
+            HGOTO_DONE(SUCCEED)
+
+#ifdef H5_HAVE_PARALLEL
+        if(bypass_pb) {
+            if(H5PB_update_entry(page_buf, addr, size, buf) > 0)
+                HGOTO_ERROR(H5E_PAGEBUF, H5E_CANTUPDATE, FAIL, "failed to update PB with metadata cache")
+            HGOTO_DONE(SUCCEED)
+        } /* end if */
+#endif
+    } /* end if */
+
+    /* Update statistics */
+    if(page_buf) {
+        if(type == H5FD_MEM_DRAW || type == H5FD_MEM_GHEAP)
+            page_buf->accesses[1]++;
+        else
+            page_buf->accesses[0]++;
+    } /* end if */
+
+    /* Calculate the aligned address of the first page */
+    first_page_addr = (addr / page_buf->page_size) * page_buf->page_size;
+
+    /* For raw data calculate the aligned address of the last page and
+     * the number of pages accessed if more than 1 page is accessed
+     */
+    if(H5FD_MEM_DRAW == type) {
+        last_page_addr = (addr + size - 1) / page_buf->page_size * page_buf->page_size;
+
+        /* how many pages does this write span */
+        num_touched_pages = (last_page_addr/page_buf->page_size + 1) - 
+            (first_page_addr / page_buf->page_size);
+        if(first_page_addr == last_page_addr) {
+            HDassert(1 == num_touched_pages);
+            last_page_addr = HADDR_UNDEF;
+        } /* end if */
+    } /* end if */
+    /* Otherwise set last page addr to HADDR_UNDEF */
+    else {
+        num_touched_pages = 1;
+        last_page_addr = HADDR_UNDEF;
+    } /* end else */
+
+    /* Translate to file driver I/O info object */
+    fdio_info.file = fio_info->f->shared->lf;
+    fdio_info.meta_dxpl = fio_info->meta_dxpl;
+    fdio_info.raw_dxpl = fio_info->raw_dxpl;
+
+    /* Check if existing pages for raw data need to be updated since raw data access is not atomic */
+    if(H5FD_MEM_DRAW == type && size >= page_buf->page_size) {
+        /* For each touched page, check if it exists in the page buffer, and
+         * update it with the data in the buffer to keep it up to date
+         */
+        for(i = 0; i < num_touched_pages; i++) {
+            search_addr = i * page_buf->page_size + first_page_addr;
+
+            /* Special handling for the first page if it is not a full page update */
+            if(i == 0 && first_page_addr != addr) {
+                /* Lookup the page in the skip list */
+                page_entry = (H5PB_entry_t *)H5SL_search(page_buf->slist_ptr, (void *)(&search_addr));
+                if(page_entry) {
+                    offset = addr - first_page_addr;
+                    HDassert(page_buf->page_size > offset);
+
+                    /* Update page's data */
+                    HDmemcpy((uint8_t *)page_entry->page_buf_ptr + offset, buf, page_buf->page_size - (size_t)offset);
+
+                    /* Mark page dirty and push to top of LRU */
+                    page_entry->is_dirty = TRUE;
+                    H5PB__MOVE_TO_TOP_LRU(page_buf, page_entry)
+                } /* end if */
+            } /* end if */
+            /* Special handling for the last page if it is not a full page update */
+            else if(num_touched_pages > 1 && i == (num_touched_pages - 1) && 
+                    (search_addr + page_buf->page_size) != (addr + size)) {
+                HDassert(search_addr+page_buf->page_size > addr+size);
+
+                /* Lookup the page in the skip list */
+                page_entry = (H5PB_entry_t *)H5SL_search(page_buf->slist_ptr, (void *)(&search_addr));
+                if(page_entry) {
+                    offset = (num_touched_pages - 2) * page_buf->page_size + 
+                        (page_buf->page_size - (addr - first_page_addr));
+
+                    /* Update page's data */
+                    HDmemcpy(page_entry->page_buf_ptr, (const uint8_t *)buf + offset, 
+                             (size_t)((addr + size) - last_page_addr));
+
+                    /* Mark page dirty and push to top of LRU */
+                    page_entry->is_dirty = TRUE;
+                    H5PB__MOVE_TO_TOP_LRU(page_buf, page_entry)
+                } /* end if */
+            } /* end else-if */
+            /* Discard all fully written pages from the page buffer */
+            else {
+                page_entry = (H5PB_entry_t *)H5SL_remove(page_buf->slist_ptr, (void *)(&search_addr));
+                if(page_entry) {
+                    /* Remove from LRU list */
+                    H5PB__REMOVE_LRU(page_buf, page_entry)
+
+                    /* Decrement page count of appropriate type */
+                    if(H5F_MEM_PAGE_DRAW == page_entry->type || H5F_MEM_PAGE_GHEAP == page_entry->type)
+                        page_buf->raw_count--;
+                    else
+                        page_buf->meta_count--;
+
+                    /* Free page info */
+                    page_entry->page_buf_ptr = H5FL_FAC_FREE(page_buf->page_fac, page_entry->page_buf_ptr);
+                    page_entry = H5FL_FREE(H5PB_entry_t, page_entry);
+                } /* end if */
+            } /* end else */
+        } /* end for */
+    } /* end if */
+    else {
+        /* An access could span 1 or 2 PBs at this point so we need to handle that */
+        HDassert(1 == num_touched_pages || 2 == num_touched_pages);
+        for(i = 0; i < num_touched_pages; i++) {
+            haddr_t buf_offset;
+
+            /* Calculate the aligned address of the page to search for it in the skip list */
+            search_addr = (0 == i ? first_page_addr : last_page_addr);
+
+            /* Calculate the access size if the access spans more than 1 page */
+            if(1 == num_touched_pages)
+                access_size = size;
+            else
+                access_size = (0 == i ? (size_t)(first_page_addr + page_buf->page_size - addr) : (size - access_size));
+
+            /* Lookup the page in the skip list */
+            page_entry = (H5PB_entry_t *)H5SL_search(page_buf->slist_ptr, (void *)(&search_addr));
+
+            /* If found */
+            if(page_entry) {
+                offset = (0 == i ? addr - page_entry->addr : 0);
+                buf_offset = (0 == i ? 0 : size - access_size);
+
+                /* Copy the requested data from the input buffer into the page */
+                HDmemcpy((uint8_t *)page_entry->page_buf_ptr + offset, (const uint8_t *)buf + buf_offset, access_size);
+
+                /* Mark page dirty and push to top of LRU */
+                page_entry->is_dirty = TRUE;
+                H5PB__MOVE_TO_TOP_LRU(page_buf, page_entry)
+
+                /* Update statistics */
+                if(type == H5FD_MEM_DRAW || type == H5FD_MEM_GHEAP)
+                    page_buf->hits[1]++;
+                else
+                    page_buf->hits[0]++;
+            } /* end if */
+            /* If not found */ 
+            else {
+                void *new_page_buf;
+                size_t page_size = page_buf->page_size;
+
+                /* Make space for new entry */
+                if((H5SL_count(page_buf->slist_ptr) * page_buf->page_size) >= page_buf->max_size) {
+                    htri_t can_make_space;
+
+                    /* Check if we can make space in page buffer */
+                    if((can_make_space = H5PB__make_space(fio_info, page_buf, type)) < 0)
+                        HGOTO_ERROR(H5E_PAGEBUF, H5E_NOSPACE, FAIL, "make space in Page buffer Failed")
+
+                    /* If make_space returns 0, then we can't use the page
+                     * buffer for this I/O and we need to bypass
+                     */
+                    if(0 == can_make_space) {
+                        HDassert(0 == i);
+
+                        /* Write to VFD and return */
+                        if(H5FD_write(&fdio_info, type, addr, size, buf) < 0)
+                            HGOTO_ERROR(H5E_PAGEBUF, H5E_WRITEERROR, FAIL, "driver write request failed")
+                        
+                        /* Break out of loop */
+                        break;
+                    } /* end if */
+                } /* end if */
+
+                /* Don't bother searching if there is no write access */
+                if(H5F_ACC_RDWR & H5F_INTENT(fio_info->f))
+                    /* Lookup & remove the page from the new skip list page if
+                     * it exists to see if this is a new page from the MF layer
+                     */
+                    page_entry = (H5PB_entry_t *)H5SL_remove(page_buf->mf_slist_ptr, (void *)(&search_addr));
+
+                /* Calculate offset into the buffer of the page and the user buffer */
+                offset = (0 == i ? addr - search_addr : 0);
+                buf_offset = (0 == i ? 0 : size - access_size);
+
+                /* If found, then just update the buffer pointer to the newly allocate buffer */
+                if(page_entry) {
+                    /* Allocate space for the page buffer */
+                    if(NULL == (new_page_buf = H5FL_FAC_MALLOC(page_buf->page_fac)))
+                        HGOTO_ERROR(H5E_PAGEBUF, H5E_CANTALLOC, FAIL, "memory allocation failed for page buffer entry")
+                    HDmemset(new_page_buf, 0, (size_t)offset);
+                    HDmemset((uint8_t *)new_page_buf + offset + access_size, 0, page_size - ((size_t)offset + access_size));
+
+                    page_entry->page_buf_ptr = new_page_buf;
+
+                    /* Update statistics */
+                    if(type == H5FD_MEM_DRAW || type == H5FD_MEM_GHEAP)
+                        page_buf->hits[1]++;
+                    else
+                        page_buf->hits[0]++;
+                } /* end if */
+                /* Otherwise read page through the VFD layer, but make sure we don't read past the EOA. */
+                else {
+                    haddr_t eoa, eof = HADDR_UNDEF;
+
+                    /* Allocate space for the page buffer */
+                    if(NULL == (new_page_buf = H5FL_FAC_CALLOC(page_buf->page_fac)))
+                        HGOTO_ERROR(H5E_PAGEBUF, H5E_CANTALLOC, FAIL, "memory allocation failed for page buffer entry")
+
+                    /* Create the new loaded PB entry */
+                    if(NULL == (page_entry = H5FL_CALLOC(H5PB_entry_t)))
+                        HGOTO_ERROR(H5E_PAGEBUF, H5E_CANTALLOC, FAIL, "memory allocation failed")
+
+                    page_entry->page_buf_ptr = new_page_buf;
+                    page_entry->addr = search_addr;
+                    page_entry->type = (H5F_mem_page_t)type;
+
+                    /* Retrieve the 'eoa' for the file */
+                    if(HADDR_UNDEF == (eoa = H5F_get_eoa(fio_info->f, type)))
+                        HGOTO_ERROR(H5E_PAGEBUF, H5E_CANTGET, FAIL, "driver get_eoa request failed")
+
+                    /* If the entire page falls outside the EOA, then fail */
+                    if(search_addr > eoa)
+                        HGOTO_ERROR(H5E_PAGEBUF, H5E_BADVALUE, FAIL, "writing to a page that is outside the file EOA")
+
+                    /* Retrieve the 'eof' for the file - The MPI-VFD EOF
+                     * returned will most likely be HADDR_UNDEF, so skip
+                     * that check.
+                     */
+                    if(!H5F_HAS_FEATURE(fio_info->f, H5FD_FEAT_HAS_MPI))
+                        if(HADDR_UNDEF == (eof = H5FD_get_eof(fio_info->f->shared->lf, H5FD_MEM_DEFAULT)))
+                            HGOTO_ERROR(H5E_PAGEBUF, H5E_CANTGET, FAIL, "driver get_eof request failed")
+
+                    /* Adjust the read size to not go beyond the EOA */
+                    if(search_addr + page_size > eoa)
+                        page_size = (size_t)(eoa - search_addr);
+
+                    if(search_addr < eof) {
+                        if(H5FD_read(&fdio_info, type, search_addr, page_size, new_page_buf) < 0)
+                            HGOTO_ERROR(H5E_PAGEBUF, H5E_READERROR, FAIL, "driver read request failed")
+
+                        /* Update statistics */
+                        if(type == H5FD_MEM_DRAW || type == H5FD_MEM_GHEAP)
+                            page_buf->misses[1]++;
+                        else
+                            page_buf->misses[0]++;
+                    } /* end if */
+                } /* end else */
+
+                /* Copy the requested data from the page into the input buffer */
+                HDmemcpy((uint8_t *)new_page_buf + offset, (const uint8_t *)buf+buf_offset, access_size);
+
+                /* Page is dirty now */
+                page_entry->is_dirty = TRUE;
+
+                /* Insert page into PB, evicting other pages as necessary */
+                if(H5PB__insert_entry(page_buf, page_entry) < 0)
+                    HGOTO_ERROR(H5E_PAGEBUF, H5E_CANTSET, FAIL, "error inserting new page in page buffer")
+            } /* end else */
+        } /* end for */
+    } /* end else */
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5PB_write() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:	H5PB__insert_entry()
+ *
+ * Purpose: ??? 
+ *
+ *          This function was created without documentation.
+ *          What follows is my best understanding of Mohamad's intent.
+ *
+ *	    Insert the supplied page into the page buffer, both the
+ *          skip list and the LRU.
+ *
+ *          As best I can tell, this function imposes no limit on the
+ *          number of entries in the page buffer beyond an assertion
+ *          failure it the page count exceeds the limit.
+ *
+ *                                               JRM -- 12/22/16
+ *
+ *
+ * Return:	Non-negative on success/Negative on failure
+ *
+ * Programmer:	Mohamad Chaarawi
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t 
+H5PB__insert_entry(H5PB_t *page_buf, H5PB_entry_t *page_entry)
+{
+    herr_t ret_value = SUCCEED;    /* Return value */
+
+    FUNC_ENTER_STATIC
+
+    /* Insert entry in skip list */
+    if(H5SL_insert(page_buf->slist_ptr, page_entry, &(page_entry->addr)) < 0)
+        HGOTO_ERROR(H5E_PAGEBUF, H5E_CANTINSERT, FAIL, "can't insert entry in skip list")
+    HDassert(H5SL_count(page_buf->slist_ptr) * page_buf->page_size <= page_buf->max_size);
+
+    /* Increment appropriate page count */
+    if(H5F_MEM_PAGE_DRAW == page_entry->type || H5F_MEM_PAGE_GHEAP == page_entry->type)
+        page_buf->raw_count++;
+    else
+        page_buf->meta_count++;
+
+    /* Insert entry in LRU */
+    H5PB__INSERT_LRU(page_buf, page_entry)
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5PB__insert_entry() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:	H5PB__make_space()
+ *
+ * Purpose: ??? 
+ *
+ *          This function was created without documentation.
+ *          What follows is my best understanding of Mohamad's intent.
+ *
+ *          If necessary and if possible, evict a page from the page 
+ *          buffer to make space for the supplied page.  Depending on 
+ *	    the page buffer configuration and contents, and the page 
+ *          supplied this may or may not be possible.
+ *
+ *                                             JRM -- 12/22/16
+ *
+ * Return:	Non-negative on success/Negative on failure
+ *
+ * Programmer:	Mohamad Chaarawi
+ *
+ *-------------------------------------------------------------------------
+ */
+static htri_t 
+H5PB__make_space(const H5F_io_info2_t *fio_info, H5PB_t *page_buf,
+    H5FD_mem_t inserted_type)
+{
+    H5PB_entry_t *page_entry;   /* Pointer to page eviction candidate */
+    htri_t ret_value = TRUE;    /* Return value */
+
+    FUNC_ENTER_STATIC
+
+    /* Sanity check */
+    HDassert(fio_info);
+    HDassert(page_buf);
+
+    /* Get oldest entry */
+    page_entry = page_buf->LRU_tail_ptr;
+
+    if(H5FD_MEM_DRAW == inserted_type) {
+        /* If threshould is 100% metadata and page buffer is full of
+           metadata, then we can't make space for raw data */
+        if(0 == page_buf->raw_count && page_buf->min_meta_count == page_buf->meta_count) {
+            HDassert(page_buf->meta_count * page_buf->page_size == page_buf->max_size);
+            HGOTO_DONE(FALSE)
+        } /* end if */
+
+        /* check the metadata threshold before evicting metadata items */
+        while(1) {
+            if(page_entry->prev && H5F_MEM_PAGE_META == page_entry->type && 
+                    page_buf->min_meta_count >= page_buf->meta_count)
+                page_entry = page_entry->prev;
+            else
+                break;
+        } /* end while */
+    } /* end if */
+    else {
+        /* If threshould is 100% raw data and page buffer is full of
+           raw data, then we can't make space for meta data */
+        if(0 == page_buf->meta_count && page_buf->min_raw_count == page_buf->raw_count) {
+            HDassert(page_buf->raw_count * page_buf->page_size == page_buf->max_size);
+            HGOTO_DONE(FALSE)
+        } /* end if */
+
+        /* check the raw data threshold before evicting raw data items */
+        while(1) {
+            if(page_entry->prev && (H5F_MEM_PAGE_DRAW == page_entry->type || H5F_MEM_PAGE_GHEAP == page_entry->type) && 
+                    page_buf->min_raw_count >= page_buf->raw_count)
+                page_entry = page_entry->prev;
+            else
+                break;
+        } /* end while */
+    } /* end else */
+
+    /* Remove from page index */
+    if(NULL == H5SL_remove(page_buf->slist_ptr, &(page_entry->addr)))
+        HGOTO_ERROR(H5E_PAGEBUF, H5E_BADVALUE, FAIL, "Tail Page Entry is not in skip list")
+
+    /* Remove entry from LRU list */
+    H5PB__REMOVE_LRU(page_buf, page_entry)
+    HDassert(H5SL_count(page_buf->slist_ptr) == page_buf->LRU_list_len);
+
+    /* Decrement appropriate page type counter */
+    if(H5F_MEM_PAGE_DRAW == page_entry->type || H5F_MEM_PAGE_GHEAP == page_entry->type)
+        page_buf->raw_count--;
+    else
+        page_buf->meta_count--;
+
+    /* Flush page if dirty */
+    if(page_entry->is_dirty)
+        if(H5PB__write_entry(fio_info, page_entry) < 0)
+            HGOTO_ERROR(H5E_PAGEBUF, H5E_WRITEERROR, FAIL, "file write failed")
+
+    /* Update statistics */
+    if(page_entry->type == H5F_MEM_PAGE_DRAW || H5F_MEM_PAGE_GHEAP == page_entry->type)
+        page_buf->evictions[1]++;
+    else
+        page_buf->evictions[0]++;
+
+    /* Release page */
+    page_entry->page_buf_ptr = H5FL_FAC_FREE(page_buf->page_fac, page_entry->page_buf_ptr);
+    page_entry = H5FL_FREE(H5PB_entry_t, page_entry);
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5PB__make_space() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:	H5PB__write_entry()
+ *
+ * Purpose: ??? 
+ *
+ *          This function was created without documentation.
+ *          What follows is my best understanding of Mohamad's intent.
+ *
+ *
+ * Return:	Non-negative on success/Negative on failure
+ *
+ * Programmer:	Mohamad Chaarawi
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+H5PB__write_entry(const H5F_io_info2_t *fio_info, H5PB_entry_t *page_entry)
+{
+    haddr_t eoa;                    /* Current EOA for the file */
+    herr_t ret_value = SUCCEED;    /* Return value */
+
+    FUNC_ENTER_STATIC
+
+    /* Sanity check */
+    HDassert(fio_info);
+    HDassert(fio_info->f);
+    HDassert(page_entry);
+
+    /* Retrieve the 'eoa' for the file */
+    if(HADDR_UNDEF == (eoa = H5F_get_eoa(fio_info->f, page_entry->type)))
+        HGOTO_ERROR(H5E_PAGEBUF, H5E_CANTGET, FAIL, "driver get_eoa request failed")
+
+    /* If the starting address of the page is larger than
+     * the EOA, then the entire page is discarded without writing.
+     */
+    if(page_entry->addr <= eoa) {
+        H5FD_io_info_t fdio_info;           /* File driver I/O info */
+        size_t page_size = fio_info->f->shared->page_buf->page_size;
+
+        /* Adjust the page length if it exceeds the EOA */
+        if((page_entry->addr + page_size) > eoa)
+            page_size = (size_t)(eoa - page_entry->addr);
+
+        /* Translate to file driver I/O info object */
+        fdio_info.file = fio_info->f->shared->lf;
+        fdio_info.meta_dxpl = fio_info->meta_dxpl;
+        fdio_info.raw_dxpl = fio_info->raw_dxpl;
+
+        if(H5FD_write(&fdio_info, page_entry->type, page_entry->addr, page_size, page_entry->page_buf_ptr) < 0)
+            HGOTO_ERROR(H5E_PAGEBUF, H5E_WRITEERROR, FAIL, "file write failed")
+    } /* end if */
+
+    page_entry->is_dirty = FALSE;
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5PB__write_entry() */
+
diff --git a/src/H5PBmodule.h b/src/H5PBmodule.h
new file mode 100644
index 0000000..35da3f6
--- /dev/null
+++ b/src/H5PBmodule.h
@@ -0,0 +1,34 @@
+/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
+ * Copyright by The HDF Group.                                               *
+ * All rights reserved.                                                      *
+ *                                                                           *
+ * This file is part of HDF5.  The full HDF5 copyright notice, including     *
+ * terms governing use, modification, and redistribution, is contained in    *
+ * the files COPYING and Copyright.html.  COPYING can be found at the root   *
+ * of the source code distribution tree; Copyright.html can be found at the  *
+ * root level of an installed copy of the electronic HDF5 document set and   *
+ * is linked from the top-level documents page.  It can also be found at     *
+ * http://hdfgroup.org/HDF5/doc/Copyright.html.  If you do not have          *
+ * access to either file, you may request a copy from help@hdfgroup.org.     *
+ * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
+
+/*
+ * Programmer:	Quincey Koziol <koziol@hdfgroup.org>
+ *		Saturday, September 12, 2015
+ *
+ * Purpose:	This file contains declarations which define macros for the
+ *		H5PB package.  Including this header means that the source file
+ *		is part of the H5PB package.
+ */
+#ifndef _H5PBmodule_H
+#define _H5PBmodule_H
+
+/* Define the proper control macros for the generic FUNC_ENTER/LEAVE and error
+ *      reporting macros.
+ */
+#define H5PB_MODULE
+#define H5_MY_PKG       H5PB
+#define H5_MY_PKG_ERR   H5E_RESOURCE
+#define H5_MY_PKG_INIT  NO
+
+#endif /* _H5PBmodule_H */
diff --git a/src/H5PBpkg.h b/src/H5PBpkg.h
new file mode 100644
index 0000000..976f18d
--- /dev/null
+++ b/src/H5PBpkg.h
@@ -0,0 +1,60 @@
+/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
+ * Copyright by The HDF Group.                                               *
+ * Copyright by the Board of Trustees of the University of Illinois.         *
+ * All rights reserved.                                                      *
+ *                                                                           *
+ * This file is part of HDF5.  The full HDF5 copyright notice, including     *
+ * terms governing use, modification, and redistribution, is contained in    *
+ * the files COPYING and Copyright.html.  COPYING can be found at the root   *
+ * of the source code distribution tree; Copyright.html can be found at the  *
+ * root level of an installed copy of the electronic HDF5 document set and   *
+ * is linked from the top-level documents page.  It can also be found at     *
+ * http://hdfgroup.org/HDF5/doc/Copyright.html.  If you do not have          *
+ * access to either file, you may request a copy from help@hdfgroup.org.     *
+ * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
+
+#if !(defined H5PB_FRIEND || defined H5PB_MODULE)
+#error "Do not include this file outside the H5PB package!"
+#endif
+
+#ifndef _H5PBpkg_H
+#define _H5PBpkg_H
+
+/* Get package's private header */
+#include "H5PBprivate.h"
+
+/* Other private headers needed by this file */
+
+/**************************/
+/* Package Private Macros */
+/**************************/
+
+
+/****************************/
+/* Package Private Typedefs */
+/****************************/
+
+typedef struct H5PB_entry_t {
+    void            *page_buf_ptr;      /* Pointer to the buffer containing the data */
+    haddr_t	    addr;               /* Address of the page in the file */
+    H5F_mem_page_t  type;               /* Type of the page entry (H5F_MEM_PAGE_RAW/META) */
+    hbool_t         is_dirty;           /* Flag indicating whether the page has dirty data or not */
+
+    /* Fields supporting replacement policies */
+    struct H5PB_entry_t     *next;      /* next pointer in the LRU list */
+    struct H5PB_entry_t     *prev;      /* previous pointer in the LRU list */
+} H5PB_entry_t;
+
+
+/*****************************/
+/* Package Private Variables */
+/*****************************/
+
+
+/******************************/
+/* Package Private Prototypes */
+/******************************/
+
+
+#endif /* _H5PBpkg_H */
+
diff --git a/src/H5PBprivate.h b/src/H5PBprivate.h
new file mode 100644
index 0000000..3b5dcae
--- /dev/null
+++ b/src/H5PBprivate.h
@@ -0,0 +1,108 @@
+/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
+ * Copyright by The HDF Group.                                               *
+ * Copyright by the Board of Trustees of the University of Illinois.         *
+ * All rights reserved.                                                      *
+ *                                                                           *
+ * This file is part of HDF5.  The full HDF5 copyright notice, including     *
+ * terms governing use, modification, and redistribution, is contained in    *
+ * the files COPYING and Copyright.html.  COPYING can be found at the root   *
+ * of the source code distribution tree; Copyright.html can be found at the  *
+ * root level of an installed copy of the electronic HDF5 document set and   *
+ * is linked from the top-level documents page.  It can also be found at     *
+ * http://hdfgroup.org/HDF5/doc/Copyright.html.  If you do not have          *
+ * access to either file, you may request a copy from help@hdfgroup.org.     *
+ * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
+
+/*-------------------------------------------------------------------------
+ *
+ * Created:		H5PBprivate.h
+ *			June 2014
+ *			Mohamad Chaarawi
+ *
+ *-------------------------------------------------------------------------
+ */
+
+#ifndef _H5PBprivate_H
+#define _H5PBprivate_H
+
+/* Include package's public header */
+#ifdef NOT_YET
+#include "H5PBpublic.h"
+#endif /* NOT_YET */
+
+/* Private headers needed by this header */
+#include "H5private.h"		/* Generic Functions			*/
+#include "H5Fprivate.h"		/* File access				*/
+#include "H5FLprivate.h"	/* Free Lists                           */
+#include "H5SLprivate.h"	/* Skip List				*/
+
+
+/**************************/
+/* Library Private Macros */
+/**************************/
+
+
+/****************************/
+/* Library Private Typedefs */
+/****************************/
+
+/* Forward declaration for a page buffer entry */
+struct H5PB_entry_t;
+
+/* Typedef for the main structure for the page buffer */
+typedef struct H5PB_t {
+    size_t              max_size;           /* The total page buffer size */
+    size_t              page_size;          /* Size of a single page */
+    unsigned            min_meta_perc;      /* Minimum ratio of metadata entries required before evicting meta entries */
+    unsigned            min_raw_perc;       /* Minimum ratio of raw data entries required before evicting raw entries */
+    unsigned            meta_count;         /* Number of entries for metadata */
+    unsigned            raw_count;          /* Number of entries for raw data */
+    unsigned            min_meta_count;     /* Minimum # of entries for metadata */
+    unsigned            min_raw_count;      /* Minimum # of entries for raw data */
+
+    H5SL_t              *slist_ptr;         /* Skip list with all the active page entries */
+    H5SL_t              *mf_slist_ptr;      /* Skip list containing newly allocated page entries inserted from the MF layer */
+
+    size_t              LRU_list_len;       /* Number of entries in the LRU (identical to slist_ptr count) */
+    struct H5PB_entry_t *LRU_head_ptr;      /* Head pointer of the LRU */
+    struct H5PB_entry_t *LRU_tail_ptr;      /* Tail pointer of the LRU */
+
+    H5FL_fac_head_t     *page_fac;           /* Factory for allocating pages */
+
+    /* Statistics */
+    unsigned            accesses[2];
+    unsigned            hits[2];
+    unsigned            misses[2];
+    unsigned            evictions[2];
+    unsigned            bypasses[2];
+} H5PB_t;
+
+/*****************************/
+/* Library-private Variables */
+/*****************************/
+
+
+/***************************************/
+/* Library-private Function Prototypes */
+/***************************************/
+
+/* General routines */
+H5_DLL herr_t H5PB_create(H5F_t *file, size_t page_buffer_size, unsigned page_buf_min_meta_perc, unsigned page_buf_min_raw_perc);
+H5_DLL herr_t H5PB_flush(const H5F_io_info2_t *fio_info);
+H5_DLL herr_t H5PB_dest(H5F_t *file);
+H5_DLL herr_t H5PB_add_new_page(H5F_t *f, H5FD_mem_t type, haddr_t page_addr);
+H5_DLL herr_t H5PB_update_entry(H5PB_t *page_buf, haddr_t addr, size_t size, const void *buf);
+H5_DLL herr_t H5PB_remove_entry(const H5F_t *f, haddr_t addr);
+H5_DLL herr_t H5PB_read(const H5F_io_info2_t *fio_info, H5FD_mem_t type,
+    haddr_t addr, size_t size, void *buf/*out*/);
+H5_DLL herr_t H5PB_write(const H5F_io_info2_t *f, H5FD_mem_t type, haddr_t addr,
+    size_t size, const void *buf);
+
+/* Statistics routines */
+H5_DLL herr_t H5PB_reset_stats(H5PB_t *page_buf);
+H5_DLL herr_t H5PB_get_stats(const H5PB_t *page_buf, unsigned accesses[2],
+    unsigned hits[2], unsigned misses[2], unsigned evictions[2], unsigned bypasses[2]);
+H5_DLL herr_t H5PB_print_stats(const H5PB_t *page_buf);
+
+#endif /* !_H5PBprivate_H */
+
diff --git a/src/H5Pdeprec.c b/src/H5Pdeprec.c
index ecf2bea..d225dfa 100644
--- a/src/H5Pdeprec.c
+++ b/src/H5Pdeprec.c
@@ -488,5 +488,135 @@ done:
     FUNC_LEAVE_API(ret_value)
 } /* end H5Pget_version() */
 
+/*-------------------------------------------------------------------------
+ * Function:	H5Pset_file_space
+ *
+ * Purpose:	    It is mapped to H5Pset_file_space_strategy().
+ *
+ * Return:	    Non-negative on success/Negative on failure
+ *
+ * Programmer:	Vailin Choi; Jan 2017
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5Pset_file_space(hid_t plist_id, H5F_file_space_type_t strategy, hsize_t threshold)
+{
+
+    H5F_fspace_strategy_t new_strategy;                     /* File space strategy type */
+    hbool_t new_persist = H5F_FREE_SPACE_PERSIST_DEF;       /* Persisting free-space or not */
+    hsize_t new_threshold = H5F_FREE_SPACE_THRESHOLD_DEF;   /* Free-space section threshold */
+    H5F_file_space_type_t in_strategy = strategy;           /* Input strategy */
+    hsize_t in_threshold = threshold;                       /* Input threshold */
+    herr_t ret_value = SUCCEED;                             /* Return value */
+
+    FUNC_ENTER_API(FAIL)
+    H5TRACE3("e", "iFfh", plist_id, strategy, threshold);
+
+    if((unsigned)in_strategy >= H5F_FILE_SPACE_NTYPES)
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "invalid strategy")
+    /*
+     *  For 1.10.0 H5Pset_file_space:
+     *      If strategy is zero, the property is not changed; 
+     *      the existing strategy is retained.
+     *      If threshold is zero, the property is not changed; 
+     *      the existing threshold is retained.
+     */
+    if(!in_strategy)
+        H5Pget_file_space(plist_id, &in_strategy, NULL);
+    if(!in_threshold)
+        H5Pget_file_space(plist_id, NULL, &in_threshold);
+
+    switch(in_strategy) {
+        case H5F_FILE_SPACE_ALL_PERSIST:
+            new_strategy = H5F_FSPACE_STRATEGY_FSM_AGGR;
+            new_persist = TRUE;
+            new_threshold = in_threshold;
+            break;
+    
+        case H5F_FILE_SPACE_ALL:
+            new_strategy = H5F_FSPACE_STRATEGY_FSM_AGGR;
+            new_threshold = in_threshold;
+            break;
+
+        case H5F_FILE_SPACE_AGGR_VFD:
+            new_strategy = H5F_FSPACE_STRATEGY_AGGR;
+            break;
+
+        case H5F_FILE_SPACE_VFD:
+            new_strategy = H5F_FSPACE_STRATEGY_NONE;
+            break;
+        
+        case H5F_FILE_SPACE_NTYPES:
+        case H5F_FILE_SPACE_DEFAULT:
+        default:
+            HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "invalid file space strategy")
+    }
+
+    if(H5Pset_file_space_strategy(plist_id, new_strategy, new_persist, new_threshold) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTSET, FAIL, "can't set file space strategy")
+
+done:
+    FUNC_LEAVE_API(ret_value)
+} /* H5Pset_file_space() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:	H5Pget_file_space
+ *
+ * Purpose:	    It is mapped to H5Pget_file_space_strategy().
+ *
+ * Return:	    Non-negative on success/Negative on failure
+ *
+ * Programmer:	Vailin Choi; Jan 2017
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5Pget_file_space(hid_t plist_id, H5F_file_space_type_t *strategy, hsize_t *threshold)
+{
+    H5F_fspace_strategy_t new_strategy;     /* File space strategy type */
+    hbool_t new_persist;                    /* Persisting free-space or not */
+    hsize_t new_threshold;                  /* Free-space section threshold */
+    herr_t ret_value = SUCCEED;             /* Return value */
+
+    FUNC_ENTER_API(FAIL)
+    H5TRACE3("e", "i*Ff*h", plist_id, strategy, threshold);
+
+    /* Get current file space info */
+    if(H5Pget_file_space_strategy(plist_id, &new_strategy, &new_persist, &new_threshold) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't get file space strategy")
+
+    /* Get value(s) */
+    if(strategy) {
+        switch(new_strategy) {
+
+            case H5F_FSPACE_STRATEGY_FSM_AGGR:
+                if(new_persist)
+                    *strategy = H5F_FILE_SPACE_ALL_PERSIST;
+                else
+                    *strategy = H5F_FILE_SPACE_ALL;
+            break;
+
+            case H5F_FSPACE_STRATEGY_AGGR:
+                *strategy = H5F_FILE_SPACE_AGGR_VFD;
+                break;
+
+            case H5F_FSPACE_STRATEGY_NONE:
+                *strategy = H5F_FILE_SPACE_VFD;
+                break;
+
+            case H5F_FSPACE_STRATEGY_PAGE:
+            case H5F_FSPACE_STRATEGY_NTYPES:
+            default:
+                HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "invalid file space strategy")
+        }
+    }
+
+    if(threshold)
+        *threshold = new_threshold;
+
+done:
+    FUNC_LEAVE_API(ret_value)
+} /* H5Pget_file_space() */
 #endif /* H5_NO_DEPRECATED_SYMBOLS */
 
diff --git a/src/H5Pfapl.c b/src/H5Pfapl.c
index 7ea0fe0..7865fdf 100644
--- a/src/H5Pfapl.c
+++ b/src/H5Pfapl.c
@@ -80,18 +80,18 @@
 #define H5F_ACS_PREEMPT_READ_CHUNKS_DEC         H5P__decode_double
 /* Definition for threshold for alignment */
 #define H5F_ACS_ALIGN_THRHD_SIZE                sizeof(hsize_t)
-#define H5F_ACS_ALIGN_THRHD_DEF                 1
+#define H5F_ACS_ALIGN_THRHD_DEF                 H5F_ALIGN_THRHD_DEF
 #define H5F_ACS_ALIGN_THRHD_ENC                 H5P__encode_hsize_t
 #define H5F_ACS_ALIGN_THRHD_DEC                 H5P__decode_hsize_t
 /* Definition for alignment */
 #define H5F_ACS_ALIGN_SIZE                      sizeof(hsize_t)
-#define H5F_ACS_ALIGN_DEF                       1
+#define H5F_ACS_ALIGN_DEF                       H5F_ALIGN_DEF
 #define H5F_ACS_ALIGN_ENC                       H5P__encode_hsize_t
 #define H5F_ACS_ALIGN_DEC                       H5P__decode_hsize_t
 /* Definition for minimum metadata allocation block size (when
    aggregating metadata allocations. */
 #define H5F_ACS_META_BLOCK_SIZE_SIZE            sizeof(hsize_t)
-#define H5F_ACS_META_BLOCK_SIZE_DEF             2048
+#define H5F_ACS_META_BLOCK_SIZE_DEF             H5F_META_BLOCK_SIZE_DEF
 #define H5F_ACS_META_BLOCK_SIZE_ENC             H5P__encode_hsize_t
 #define H5F_ACS_META_BLOCK_SIZE_DEC             H5P__decode_hsize_t
 /* Definition for maximum sieve buffer size (when data sieving
@@ -103,7 +103,7 @@
 /* Definition for minimum "small data" allocation block size (when
    aggregating "small" raw data allocations. */
 #define H5F_ACS_SDATA_BLOCK_SIZE_SIZE           sizeof(hsize_t)
-#define H5F_ACS_SDATA_BLOCK_SIZE_DEF            2048
+#define H5F_ACS_SDATA_BLOCK_SIZE_DEF            H5F_SDATA_BLOCK_SIZE_DEF
 #define H5F_ACS_SDATA_BLOCK_SIZE_ENC            H5P__encode_hsize_t
 #define H5F_ACS_SDATA_BLOCK_SIZE_DEC            H5P__decode_hsize_t
 /* Definition for garbage-collect references */
@@ -231,6 +231,21 @@
 #define H5F_ACS_META_CACHE_INIT_IMAGE_CONFIG_ENC  H5P__facc_cache_image_config_enc
 #define H5F_ACS_META_CACHE_INIT_IMAGE_CONFIG_DEC  H5P__facc_cache_image_config_dec
 #define H5F_ACS_META_CACHE_INIT_IMAGE_CONFIG_CMP  H5P__facc_cache_image_config_cmp
+/* Definition for total size of page buffer(bytes) */
+#define H5F_ACS_PAGE_BUFFER_SIZE_SIZE           sizeof(size_t)
+#define H5F_ACS_PAGE_BUFFER_SIZE_DEF            0
+#define H5F_ACS_PAGE_BUFFER_SIZE_ENC            H5P__encode_size_t
+#define H5F_ACS_PAGE_BUFFER_SIZE_DEC            H5P__decode_size_t
+/* Definition for minimum metadata size of page buffer(bytes) */
+#define H5F_ACS_PAGE_BUFFER_MIN_META_PERC_SIZE           sizeof(unsigned)
+#define H5F_ACS_PAGE_BUFFER_MIN_META_PERC_DEF            0
+#define H5F_ACS_PAGE_BUFFER_MIN_META_PERC_ENC            H5P__encode_unsigned
+#define H5F_ACS_PAGE_BUFFER_MIN_META_PERC_DEC            H5P__decode_unsigned
+/* Definition for minimum raw data size of page buffer(bytes) */
+#define H5F_ACS_PAGE_BUFFER_MIN_RAW_PERC_SIZE           sizeof(unsigned)
+#define H5F_ACS_PAGE_BUFFER_MIN_RAW_PERC_DEF            0
+#define H5F_ACS_PAGE_BUFFER_MIN_RAW_PERC_ENC            H5P__encode_unsigned
+#define H5F_ACS_PAGE_BUFFER_MIN_RAW_PERC_DEC            H5P__decode_unsigned
 
 
 /******************/
@@ -359,6 +374,9 @@ static const H5P_coll_md_read_flag_t H5F_def_coll_md_read_flag_g = H5F_ACS_COLL_
 static const hbool_t H5F_def_coll_md_write_flag_g = H5F_ACS_COLL_MD_WRITE_FLAG_DEF;  /* Default setting for the collective metedata write flag */
 #endif /* H5_HAVE_PARALLEL */
 static const H5AC_cache_image_config_t H5F_def_mdc_initCacheImageCfg_g = H5F_ACS_META_CACHE_INIT_IMAGE_CONFIG_DEF;  /* Default metadata cache image settings */
+static const size_t H5F_def_page_buf_size_g = H5F_ACS_PAGE_BUFFER_SIZE_DEF;      /* Default page buffer size */
+static const unsigned H5F_def_page_buf_min_meta_perc_g = H5F_ACS_PAGE_BUFFER_MIN_META_PERC_DEF;      /* Default page buffer minimum metadata size */
+static const unsigned H5F_def_page_buf_min_raw_perc_g = H5F_ACS_PAGE_BUFFER_MIN_RAW_PERC_DEF;      /* Default page buffer minumum raw data size */
 
 
 /*-------------------------------------------------------------------------
@@ -574,6 +592,22 @@ H5P__facc_reg_prop(H5P_genclass_t *pclass)
             NULL, NULL, H5F_ACS_META_CACHE_INIT_IMAGE_CONFIG_CMP, NULL) < 0)
         HGOTO_ERROR(H5E_PLIST, H5E_CANTINSERT, FAIL, "can't insert property into class")
 
+    /* Register the size of the page buffer size */
+    if(H5P_register_real(pclass, H5F_ACS_PAGE_BUFFER_SIZE_NAME, H5F_ACS_PAGE_BUFFER_SIZE_SIZE, &H5F_def_page_buf_size_g, 
+            NULL, NULL, NULL, H5F_ACS_PAGE_BUFFER_SIZE_ENC, H5F_ACS_PAGE_BUFFER_SIZE_DEC, 
+            NULL, NULL, NULL, NULL) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTINSERT, FAIL, "can't insert property into class")
+    /* Register the size of the page buffer minimum metadata size */
+    if(H5P_register_real(pclass, H5F_ACS_PAGE_BUFFER_MIN_META_PERC_NAME, H5F_ACS_PAGE_BUFFER_MIN_META_PERC_SIZE, &H5F_def_page_buf_min_meta_perc_g, 
+            NULL, NULL, NULL, H5F_ACS_PAGE_BUFFER_MIN_META_PERC_ENC, H5F_ACS_PAGE_BUFFER_MIN_META_PERC_DEC, 
+            NULL, NULL, NULL, NULL) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTINSERT, FAIL, "can't insert property into class")
+    /* Register the size of the page buffer minimum raw data size */
+    if(H5P_register_real(pclass, H5F_ACS_PAGE_BUFFER_MIN_RAW_PERC_NAME, H5F_ACS_PAGE_BUFFER_MIN_RAW_PERC_SIZE, &H5F_def_page_buf_min_raw_perc_g, 
+            NULL, NULL, NULL, H5F_ACS_PAGE_BUFFER_MIN_RAW_PERC_ENC, H5F_ACS_PAGE_BUFFER_MIN_RAW_PERC_DEC, 
+            NULL, NULL, NULL, NULL) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTINSERT, FAIL, "can't insert property into class")
+
 done:
     FUNC_LEAVE_NOAPI(ret_value)
 } /* end H5P__facc_reg_prop() */
@@ -4681,3 +4715,93 @@ done:
 } /* end H5Pget_coll_metadata_write() */
 #endif /* H5_HAVE_PARALLEL */
 
+
+/*-------------------------------------------------------------------------
+ * Function:	H5Pset_page_buffer_size
+ *
+ * Purpose:     Set the maximum page buffering size. This has to be a
+ *              multiple of the page allocation size which must be enabled;
+ *              otherwise file create/open will fail.
+ *
+ * Return:	Non-negative on success/Negative on failure
+ *
+ * Programmer:	Mohamad Chaarawi
+ *              June 2015
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5Pset_page_buffer_size(hid_t plist_id, size_t buf_size, unsigned min_meta_perc, unsigned min_raw_perc)
+{
+    H5P_genplist_t *plist;      /* Property list pointer */
+    herr_t ret_value = SUCCEED;   /* return value */
+
+    FUNC_ENTER_API(FAIL)
+    H5TRACE4("e", "izIuIu", plist_id, buf_size, min_meta_perc, min_raw_perc);
+
+    /* Get the plist structure */
+    if(NULL == (plist = H5P_object_verify(plist_id, H5P_FILE_ACCESS)))
+        HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, FAIL, "can't find object for ID")
+
+    if(min_meta_perc > 100)
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "Minimum metadata fractions must be between 0 and 100 inclusive")
+    if(min_raw_perc > 100)
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "Minimum rawdata fractions must be between 0 and 100 inclusive")
+
+    if(min_meta_perc + min_raw_perc > 100)
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "Sum of minimum metadata and raw data fractions can't be bigger than 100");
+
+    /* Set size */
+    if(H5P_set(plist, H5F_ACS_PAGE_BUFFER_SIZE_NAME, &buf_size) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTSET,FAIL, "can't set page buffer size")
+    if(H5P_set(plist, H5F_ACS_PAGE_BUFFER_MIN_META_PERC_NAME, &min_meta_perc) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTSET,FAIL, "can't set percentage of min metadata entries")
+    if(H5P_set(plist, H5F_ACS_PAGE_BUFFER_MIN_RAW_PERC_NAME, &min_raw_perc) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTSET,FAIL, "can't set percentage of min rawdata entries")
+
+done:
+    FUNC_LEAVE_API(ret_value)
+} /* end H5Pset_page_buffer_size() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:	H5Pget_page_buffer_size
+ *
+ * Purpose:	Retrieves the maximum page buffer size.
+ *
+ * Return:	Non-negative on success/Negative on failure
+ *
+ * Programmer:	Mohamad Chaarawi
+ *              June 2015
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5Pget_page_buffer_size(hid_t plist_id, size_t *buf_size, unsigned *min_meta_perc, unsigned *min_raw_perc)
+{
+    H5P_genplist_t *plist;      /* Property list pointer */
+    herr_t ret_value = SUCCEED;   /* return value */
+
+    FUNC_ENTER_API(FAIL)
+    H5TRACE4("e", "i*z*Iu*Iu", plist_id, buf_size, min_meta_perc, min_raw_perc);
+
+    /* Get the plist structure */
+    if(NULL == (plist = H5P_object_verify(plist_id, H5P_FILE_ACCESS)))
+        HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, FAIL, "can't find object for ID")
+
+    /* Get size */
+
+    if(buf_size)
+        if(H5P_get(plist, H5F_ACS_PAGE_BUFFER_SIZE_NAME, buf_size) < 0)
+            HGOTO_ERROR(H5E_PLIST, H5E_CANTGET,FAIL, "can't get page buffer size")
+    if(min_meta_perc)
+        if(H5P_get(plist, H5F_ACS_PAGE_BUFFER_MIN_META_PERC_NAME, min_meta_perc) < 0)
+            HGOTO_ERROR(H5E_PLIST, H5E_CANTGET,FAIL, "can't get page buffer minimum metadata percent")
+    if(min_raw_perc)
+        if(H5P_get(plist, H5F_ACS_PAGE_BUFFER_MIN_RAW_PERC_NAME, min_raw_perc) < 0)
+            HGOTO_ERROR(H5E_PLIST, H5E_CANTGET,FAIL, "can't get page buffer minimum raw data percent")
+
+done:
+    FUNC_LEAVE_API(ret_value)
+} /* end H5Pget_page_buffer_size() */
+
diff --git a/src/H5Pfcpl.c b/src/H5Pfcpl.c
index d451982..c778801 100644
--- a/src/H5Pfcpl.c
+++ b/src/H5Pfcpl.c
@@ -97,14 +97,23 @@
 #define H5F_CRT_SHMSG_BTREE_MIN_ENC     H5P__encode_unsigned
 #define H5F_CRT_SHMSG_BTREE_MIN_DEC     H5P__decode_unsigned
 /* Definitions for file space handling strategy */
-#define H5F_CRT_FILE_SPACE_STRATEGY_SIZE       sizeof(unsigned)
-#define H5F_CRT_FILE_SPACE_STRATEGY_DEF        H5F_FILE_SPACE_STRATEGY_DEF
-#define H5F_CRT_FILE_SPACE_STRATEGY_ENC        H5P__encode_unsigned
-#define H5F_CRT_FILE_SPACE_STRATEGY_DEC        H5P__decode_unsigned
-#define H5F_CRT_FREE_SPACE_THRESHOLD_SIZE      sizeof(hsize_t)
-#define H5F_CRT_FREE_SPACE_THRESHOLD_DEF       H5F_FREE_SPACE_THRESHOLD_DEF
-#define H5F_CRT_FREE_SPACE_THRESHOLD_ENC       H5P__encode_hsize_t
-#define H5F_CRT_FREE_SPACE_THRESHOLD_DEC       H5P__decode_hsize_t
+#define H5F_CRT_FILE_SPACE_STRATEGY_SIZE        sizeof(H5F_fspace_strategy_t)
+#define H5F_CRT_FILE_SPACE_STRATEGY_DEF         H5F_FILE_SPACE_STRATEGY_DEF
+#define H5F_CRT_FILE_SPACE_STRATEGY_ENC         H5P__fcrt_fspace_strategy_enc
+#define H5F_CRT_FILE_SPACE_STRATEGY_DEC         H5P__fcrt_fspace_strategy_dec
+#define H5F_CRT_FREE_SPACE_PERSIST_SIZE         sizeof(hbool_t)
+#define H5F_CRT_FREE_SPACE_PERSIST_DEF          H5F_FREE_SPACE_PERSIST_DEF
+#define H5F_CRT_FREE_SPACE_PERSIST_ENC          H5P__encode_hbool_t
+#define H5F_CRT_FREE_SPACE_PERSIST_DEC          H5P__decode_hbool_t
+#define H5F_CRT_FREE_SPACE_THRESHOLD_SIZE       sizeof(hsize_t)
+#define H5F_CRT_FREE_SPACE_THRESHOLD_DEF        H5F_FREE_SPACE_THRESHOLD_DEF
+#define H5F_CRT_FREE_SPACE_THRESHOLD_ENC        H5P__encode_hsize_t
+#define H5F_CRT_FREE_SPACE_THRESHOLD_DEC        H5P__decode_hsize_t
+/* Definitions for file space page size in support of level-2 page caching */
+#define H5F_CRT_FILE_SPACE_PAGE_SIZE_SIZE       sizeof(hsize_t)
+#define H5F_CRT_FILE_SPACE_PAGE_SIZE_DEF        H5F_FILE_SPACE_PAGE_SIZE_DEF
+#define H5F_CRT_FILE_SPACE_PAGE_SIZE_ENC        H5P__encode_hsize_t
+#define H5F_CRT_FILE_SPACE_PAGE_SIZE_DEC        H5P__decode_hsize_t
 
 
 /******************/
@@ -131,6 +140,8 @@ static herr_t H5P__fcrt_shmsg_index_types_enc(const void *value, void **_pp, siz
 static herr_t H5P__fcrt_shmsg_index_types_dec(const void **_pp, void *value);
 static herr_t H5P__fcrt_shmsg_index_minsize_enc(const void *value, void **_pp, size_t *size);
 static herr_t H5P__fcrt_shmsg_index_minsize_dec(const void **_pp, void *value);
+static herr_t H5P__fcrt_fspace_strategy_enc(const void *value, void **_pp, size_t *size);
+static herr_t H5P__fcrt_fspace_strategy_dec(const void **_pp, void *_value);
 
 
 /*********************/
@@ -178,8 +189,10 @@ static const unsigned H5F_def_sohm_index_flags_g[H5O_SHMESG_MAX_NINDEXES]    = H
 static const unsigned H5F_def_sohm_index_minsizes_g[H5O_SHMESG_MAX_NINDEXES] = H5F_CRT_SHMSG_INDEX_MINSIZE_DEF;
 static const unsigned H5F_def_sohm_list_max_g  = H5F_CRT_SHMSG_LIST_MAX_DEF;
 static const unsigned H5F_def_sohm_btree_min_g  = H5F_CRT_SHMSG_BTREE_MIN_DEF;
-static const unsigned H5F_def_file_space_strategy_g = H5F_CRT_FILE_SPACE_STRATEGY_DEF;
+static const H5F_fspace_strategy_t H5F_def_file_space_strategy_g = H5F_CRT_FILE_SPACE_STRATEGY_DEF;
+static const hbool_t H5F_def_free_space_persist_g = H5F_CRT_FREE_SPACE_PERSIST_DEF;
 static const hsize_t H5F_def_free_space_threshold_g = H5F_CRT_FREE_SPACE_THRESHOLD_DEF;
+static const hsize_t H5F_def_file_space_page_size_g = H5F_CRT_FILE_SPACE_PAGE_SIZE_DEF;
 
 
 
@@ -267,12 +280,24 @@ H5P_fcrt_reg_prop(H5P_genclass_t *pclass)
             NULL, NULL, NULL, NULL) < 0)
         HGOTO_ERROR(H5E_PLIST, H5E_CANTINSERT, FAIL, "can't insert property into class")
 
+    /* Register the free-space persist flag */
+    if(H5P_register_real(pclass, H5F_CRT_FREE_SPACE_PERSIST_NAME, H5F_CRT_FREE_SPACE_PERSIST_SIZE, &H5F_def_free_space_persist_g,
+            NULL, NULL, NULL, H5F_CRT_FREE_SPACE_PERSIST_ENC, H5F_CRT_FREE_SPACE_PERSIST_DEC,
+            NULL, NULL, NULL, NULL) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTINSERT, FAIL, "can't insert property into class")
+
     /* Register the free space section threshold */
     if(H5P_register_real(pclass, H5F_CRT_FREE_SPACE_THRESHOLD_NAME, H5F_CRT_FREE_SPACE_THRESHOLD_SIZE, &H5F_def_free_space_threshold_g, 
             NULL, NULL, NULL, H5F_CRT_FREE_SPACE_THRESHOLD_ENC, H5F_CRT_FREE_SPACE_THRESHOLD_DEC, 
             NULL, NULL, NULL, NULL) < 0)
         HGOTO_ERROR(H5E_PLIST, H5E_CANTINSERT, FAIL, "can't insert property into class")
 
+    /* Register the file space page size */
+    if(H5P_register_real(pclass, H5F_CRT_FILE_SPACE_PAGE_SIZE_NAME, H5F_CRT_FILE_SPACE_PAGE_SIZE_SIZE, &H5F_def_file_space_page_size_g,
+            NULL, NULL, NULL, H5F_CRT_FILE_SPACE_PAGE_SIZE_ENC, H5F_CRT_FILE_SPACE_PAGE_SIZE_DEC,
+            NULL, NULL, NULL, NULL) < 0)
+         HGOTO_ERROR(H5E_PLIST, H5E_CANTINSERT, FAIL, "can't insert property into class")
+
 done:
     FUNC_LEAVE_NOAPI(ret_value)
 } /* end H5P_fcrt_reg_prop() */
@@ -1246,15 +1271,13 @@ H5Pget_shared_mesg_phase_change(hid_t plist_id, unsigned *max_list, unsigned *mi
     if(NULL == (plist = H5P_object_verify(plist_id,H5P_FILE_CREATE)))
         HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, FAIL, "can't find object for ID");
 
-    /* Get value */
-    if (max_list) {
+    /* Get value(s) */
+    if(max_list)
         if(H5P_get(plist, H5F_CRT_SHMSG_LIST_MAX_NAME, max_list) < 0)
             HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't get list maximum");
-    }
-    if (min_btree) {
+    if(min_btree)
         if(H5P_get(plist, H5F_CRT_SHMSG_BTREE_MIN_NAME, min_btree) < 0)
             HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't get SOHM information");
-    }
 
 done:
     FUNC_LEAVE_API(ret_value)
@@ -1262,15 +1285,12 @@ done:
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5Pset_file_space
+ * Function:	H5Pset_file_space_strategy
  *
- * Purpose:	Sets the strategy that the library employs in managing file space.
- *		If strategy is zero, the property is not changed; the existing
- *			strategy is retained.
- *		Sets the threshold value that the file's free space
- *			manager(s) will use to track free space sections.
- *		If threshold is zero, the property is not changed; the existing
- *			threshold is retained.
+ * Purpose:	Sets the "strategy" that the library employs in managing file space
+ *		    Sets the "persist" value as to persist free-space or not
+ *		    Sets the "threshold" value that the free space manager(s) will use to track free space sections.
+ *          Ignore "persist" and "threshold" for strategies that do not use free-space managers
  *
  * Return:	Non-negative on success/Negative on failure
  *
@@ -1279,15 +1299,16 @@ done:
  *-------------------------------------------------------------------------
  */
 herr_t
-H5Pset_file_space(hid_t plist_id, H5F_file_space_type_t strategy, hsize_t threshold)
+H5Pset_file_space_strategy(hid_t plist_id, H5F_fspace_strategy_t strategy, hbool_t persist, hsize_t threshold)
 {
     H5P_genplist_t *plist;              /* Property list pointer */
     herr_t      ret_value = SUCCEED;    /* Return value */
 
     FUNC_ENTER_API(FAIL)
-    H5TRACE3("e", "iFfh", plist_id, strategy, threshold);
+    H5TRACE4("e", "iFfbh", plist_id, strategy, persist, threshold);
 
-    if((unsigned)strategy >= H5F_FILE_SPACE_NTYPES)
+    /* Check arguments */
+    if(strategy >= H5F_FSPACE_STRATEGY_NTYPES)
         HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "invalid strategy")
 
     /* Get the plist structure */
@@ -1295,24 +1316,28 @@ H5Pset_file_space(hid_t plist_id, H5F_file_space_type_t strategy, hsize_t thresh
         HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, FAIL, "can't find object for ID")
 
     /* Set value(s), if non-zero */
-    if(strategy)
-	if(H5P_set(plist, H5F_CRT_FILE_SPACE_STRATEGY_NAME, &strategy) < 0)
-	    HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't set file space strategy")
-    if(threshold)
-	if(H5P_set(plist, H5F_CRT_FREE_SPACE_THRESHOLD_NAME, &threshold) < 0)
-	    HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't set free-space threshold")
+    if(H5P_set(plist, H5F_CRT_FILE_SPACE_STRATEGY_NAME, &strategy) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTSET, FAIL, "can't set file space strategy")
+
+    /* Ignore persist and threshold settings for strategies that do not use FSM */
+    if(strategy ==  H5F_FSPACE_STRATEGY_FSM_AGGR || strategy == H5F_FSPACE_STRATEGY_PAGE) {
+        if(H5P_set(plist, H5F_CRT_FREE_SPACE_PERSIST_NAME, &persist) < 0)
+            HGOTO_ERROR(H5E_PLIST, H5E_CANTSET, FAIL, "can't set free-space persisting status")
+
+        if(H5P_set(plist, H5F_CRT_FREE_SPACE_THRESHOLD_NAME, &threshold) < 0)
+            HGOTO_ERROR(H5E_PLIST, H5E_CANTSET, FAIL, "can't set free-space threshold")
+    } /* end if */
 
 done:
     FUNC_LEAVE_API(ret_value)
-} /* H5Pset_file_space() */
+} /* H5Pset_file_space_strategy() */
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5Pget_file_space
+ * Function:	H5Pget_file_space_strategy
  *
- * Purpose:	Retrieves the strategy that the library uses in managing file space.
- *		Retrieves the threshold value that the file's free space
- *			managers use to track free space sections.
+ * Purpose:	Retrieves the strategy, persist, and threshold that the library 
+ *          uses in managing file space.
  *
  * Return:	Non-negative on success/Negative on failure
  *
@@ -1321,13 +1346,13 @@ done:
  *-------------------------------------------------------------------------
  */
 herr_t
-H5Pget_file_space(hid_t plist_id, H5F_file_space_type_t *strategy, hsize_t *threshold)
+H5Pget_file_space_strategy(hid_t plist_id, H5F_fspace_strategy_t *strategy, hbool_t *persist, hsize_t *threshold)
 {
     H5P_genplist_t *plist;              /* Property list pointer */
     herr_t      ret_value = SUCCEED;    /* Return value */
 
     FUNC_ENTER_API(FAIL)
-    H5TRACE3("e", "i*Ff*h", plist_id, strategy, threshold);
+    H5TRACE4("e", "i*Ff*b*h", plist_id, strategy, persist, threshold);
 
     /* Get the plist structure */
     if(NULL == (plist = H5P_object_verify(plist_id,H5P_FILE_CREATE)))
@@ -1337,11 +1362,158 @@ H5Pget_file_space(hid_t plist_id, H5F_file_space_type_t *strategy, hsize_t *thre
     if(strategy)
         if(H5P_get(plist, H5F_CRT_FILE_SPACE_STRATEGY_NAME, strategy) < 0)
             HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't get file space strategy")
+    if(persist)
+        if(H5P_get(plist, H5F_CRT_FREE_SPACE_PERSIST_NAME, persist) < 0)
+            HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't get free-space persisting status")
     if(threshold)
         if(H5P_get(plist, H5F_CRT_FREE_SPACE_THRESHOLD_NAME, threshold) < 0)
             HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't get free-space threshold")
 
 done:
     FUNC_LEAVE_API(ret_value)
-} /* H5Pget_file_space() */
+} /* H5Pget_file_space_strategy() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:       H5P__fcrt_fspace_strategy_enc
+ *
+ * Purpose:        Callback routine which is called whenever the free-space
+ *                 strategy property in the file creation property list
+ *                 is encoded.
+ *
+ * Return:	   Success:	Non-negative
+ *		   Failure:	Negative
+ *
+ * Programmer:     Quincey Koziol
+ *                 Friday, December 27, 2013
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+H5P__fcrt_fspace_strategy_enc(const void *value, void **_pp, size_t *size)
+{
+    const H5F_fspace_strategy_t *strategy = (const H5F_fspace_strategy_t *)value; /* Create local alias for values */
+    uint8_t **pp = (uint8_t **)_pp;
+
+    FUNC_ENTER_STATIC_NOERR
+
+    /* Sanity check */
+    HDassert(strategy);
+    HDassert(size);
+
+    if(NULL != *pp)
+        /* Encode free-space strategy */
+        *(*pp)++ = (uint8_t)*strategy;
+
+    /* Size of free-space strategy */
+    (*size)++;
+
+    FUNC_LEAVE_NOAPI(SUCCEED)
+} /* end H5P__fcrt_fspace_strategy_enc() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:       H5P__fcrt_fspace_strategy_dec
+ *
+ * Purpose:        Callback routine which is called whenever the free-space
+ *                 strategy property in the file creation property list
+ *                 is decoded.
+ *
+ * Return:	   Success:	Non-negative
+ *		   Failure:	Negative
+ *
+ * Programmer:     Quincey Koziol
+ *                 Friday, December 27, 2013
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+H5P__fcrt_fspace_strategy_dec(const void **_pp, void *_value)
+{
+    H5F_fspace_strategy_t *strategy = (H5F_fspace_strategy_t *)_value;         /* Free-space strategy */
+    const uint8_t **pp = (const uint8_t **)_pp;
+
+    FUNC_ENTER_STATIC_NOERR
+
+    /* Sanity checks */
+    HDassert(pp);
+    HDassert(*pp);
+    HDassert(strategy);
+
+    /* Decode free-space strategy */
+    *strategy = (H5F_fspace_strategy_t)*(*pp)++;
+
+    FUNC_LEAVE_NOAPI(SUCCEED)
+} /* end H5P__fcrt_fspace_strategy_dec() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:    H5Pset_file_space_page_size
+ *
+ * Purpose:     Sets the file space page size for paged aggregation.
+ *
+ * Return:      Non-negative on success/Negative on failure
+ *
+ * Programmer:  Vailin Choi; August 2012
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5Pset_file_space_page_size(hid_t plist_id, hsize_t fsp_size)
+{
+    H5P_genplist_t *plist;              /* Property list pointer */
+    herr_t      ret_value = SUCCEED;    /* Return value */
+
+    FUNC_ENTER_API(FAIL)
+    H5TRACE2("e", "ih", plist_id, fsp_size);
+
+    /* Get the plist structure */
+    if(NULL == (plist = H5P_object_verify(plist_id,H5P_FILE_CREATE)))
+        HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, FAIL, "can't find object for ID")
+
+    if(fsp_size < H5F_FILE_SPACE_PAGE_SIZE_MIN)
+        HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, FAIL, "cannot set file space page size to less than 512")
+
+    /* Set the value*/
+    if(H5P_set(plist, H5F_CRT_FILE_SPACE_PAGE_SIZE_NAME, &fsp_size) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't set file space page size")
+
+done:
+    FUNC_LEAVE_API(ret_value)
+} /* H5Pset_file_space_page_size() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:    H5Pget_file_space_page_size
+ *
+ * Purpose:     Retrieves the file space page size for aggregating small metadata
+ *		or raw data in the parameter "fsp_size".
+ *
+ * Return:      Non-negative on success/Negative on failure
+ *
+ * Programmer:  Vailin Choi; August 2012
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5Pget_file_space_page_size(hid_t plist_id, hsize_t *fsp_size)
+{
+    H5P_genplist_t *plist;              /* Property list pointer */
+    herr_t      ret_value = SUCCEED;    /* Return value */
+
+    FUNC_ENTER_API(FAIL)
+    H5TRACE2("e", "i*h", plist_id, fsp_size);
+
+    /* Get the plist structure */
+    if(NULL == (plist = H5P_object_verify(plist_id,H5P_FILE_CREATE)))
+        HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, FAIL, "can't find object for ID")
+
+    /* Get value */
+    if(fsp_size)
+        if(H5P_get(plist, H5F_CRT_FILE_SPACE_PAGE_SIZE_NAME, fsp_size) < 0)
+            HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't get file space page size")
+
+done:
+    FUNC_LEAVE_API(ret_value)
+} /* H5Pget_file_space_page_size() */
 
diff --git a/src/H5Ppublic.h b/src/H5Ppublic.h
index 5aa8301..50b9eb0 100644
--- a/src/H5Ppublic.h
+++ b/src/H5Ppublic.h
@@ -300,8 +300,10 @@ H5_DLL herr_t H5Pset_shared_mesg_index(hid_t plist_id, unsigned index_num, unsig
 H5_DLL herr_t H5Pget_shared_mesg_index(hid_t plist_id, unsigned index_num, unsigned *mesg_type_flags, unsigned *min_mesg_size);
 H5_DLL herr_t H5Pset_shared_mesg_phase_change(hid_t plist_id, unsigned max_list, unsigned min_btree);
 H5_DLL herr_t H5Pget_shared_mesg_phase_change(hid_t plist_id, unsigned *max_list, unsigned *min_btree);
-H5_DLL herr_t H5Pset_file_space(hid_t plist_id, H5F_file_space_type_t strategy, hsize_t threshold);
-H5_DLL herr_t H5Pget_file_space(hid_t plist_id, H5F_file_space_type_t *strategy, hsize_t *threshold);
+H5_DLL herr_t H5Pset_file_space_strategy(hid_t plist_id, H5F_fspace_strategy_t strategy, hbool_t persist, hsize_t threshold);
+H5_DLL herr_t H5Pget_file_space_strategy(hid_t plist_id, H5F_fspace_strategy_t *strategy, hbool_t *persist, hsize_t *threshold);
+H5_DLL herr_t H5Pset_file_space_page_size(hid_t plist_id, hsize_t fsp_size);
+H5_DLL herr_t H5Pget_file_space_page_size(hid_t plist_id, hsize_t *fsp_size);
 
 /* File access property list (FAPL) routines */
 H5_DLL herr_t H5Pset_alignment(hid_t fapl_id, hsize_t threshold,
@@ -367,6 +369,8 @@ H5_DLL herr_t H5Pget_coll_metadata_write(hid_t plist_id, hbool_t *is_collective)
 #endif /* H5_HAVE_PARALLEL */
 H5_DLL herr_t H5Pset_mdc_image_config(hid_t plist_id, H5AC_cache_image_config_t *config_ptr);
 H5_DLL herr_t H5Pget_mdc_image_config(hid_t plist_id, H5AC_cache_image_config_t *config_ptr /*out*/);
+H5_DLL herr_t H5Pset_page_buffer_size(hid_t plist_id, size_t buf_size, unsigned min_meta_per, unsigned min_raw_per);
+H5_DLL herr_t H5Pget_page_buffer_size(hid_t plist_id, size_t *buf_size, unsigned *min_meta_per, unsigned *min_raw_per);
 
 /* Dataset creation property list (DCPL) routines */
 H5_DLL herr_t H5Pset_layout(hid_t plist_id, H5D_layout_t layout);
@@ -534,6 +538,8 @@ H5_DLL herr_t H5Pget_filter_by_id1(hid_t plist_id, H5Z_filter_t id,
 H5_DLL herr_t H5Pget_version(hid_t plist_id, unsigned *boot/*out*/,
          unsigned *freelist/*out*/, unsigned *stab/*out*/,
          unsigned *shhdr/*out*/);
+H5_DLL herr_t H5Pset_file_space(hid_t plist_id, H5F_file_space_type_t strategy, hsize_t threshold);
+H5_DLL herr_t H5Pget_file_space(hid_t plist_id, H5F_file_space_type_t *strategy, hsize_t *threshold);
 #endif /* H5_NO_DEPRECATED_SYMBOLS */
 
 #ifdef __cplusplus
diff --git a/src/H5err.txt b/src/H5err.txt
index 44c5a93..ffa9315 100644
--- a/src/H5err.txt
+++ b/src/H5err.txt
@@ -77,6 +77,7 @@ MAJOR, H5E_SOHM, Shared Object Header Messages
 MAJOR, H5E_EARRAY, Extensible Array
 MAJOR, H5E_FARRAY, Fixed Array
 MAJOR, H5E_PLUGIN, Plugin for dynamically loaded library
+MAJOR, H5E_PAGEBUF, Page Buffering
 MAJOR, H5E_NONE_MAJOR, No error
 
 # Sections (for grouping minor errors)
diff --git a/src/H5trace.c b/src/H5trace.c
index 44b2ed5..48c357a 100644
--- a/src/H5trace.c
+++ b/src/H5trace.c
@@ -895,32 +895,28 @@ H5_trace(const double *returning, const char *func, const char *type, ...)
                                 fprintf(out, "NULL");
                         } /* end if */
                         else {
-                            H5F_file_space_type_t fs_type = (H5F_file_space_type_t)va_arg(ap, int);
+                            H5F_fspace_strategy_t fs_strategy = (H5F_fspace_strategy_t)va_arg(ap, int);
 
-                            switch(fs_type) {
-                                case H5F_FILE_SPACE_DEFAULT:
-                                    fprintf(out, "H5F_FILE_SPACE_DEFAULT");
+                            switch(fs_strategy) {
+                                case H5F_FSPACE_STRATEGY_FSM_AGGR:
+                                    fprintf(out, "H5F_FSPACE_STRATEGY_FSM_AGGR");
                                     break;
 
-                                case H5F_FILE_SPACE_ALL_PERSIST:
-                                    fprintf(out, "H5F_FILE_SPACE_ALL_PERSIST");
+                                case H5F_FSPACE_STRATEGY_PAGE:
+                                    fprintf(out, "H5F_FSPACE_STRATEGY_PAGE");
                                     break;
 
-                                case H5F_FILE_SPACE_ALL:
-                                    fprintf(out, "H5F_FILE_SPACE_ALL");
+                                case H5F_FSPACE_STRATEGY_AGGR:
+                                    fprintf(out, "H5F_FSPACE_STRATEGY_AGGR");
                                     break;
 
-                                case H5F_FILE_SPACE_AGGR_VFD:
-                                    fprintf(out, "H5F_FILE_SPACE_AGGR_VFD");
+                                case H5F_FSPACE_STRATEGY_NONE:
+                                    fprintf(out, "H5F_FSPACE_STRATEGY_NONE");
                                     break;
 
-                                case H5F_FILE_SPACE_VFD:
-                                    fprintf(out, "H5F_FILE_SPACE_VFD");
-                                    break;
-
-                                case H5F_FILE_SPACE_NTYPES:
+                                case H5F_FSPACE_STRATEGY_NTYPES:
                                 default:
-                                    fprintf(out, "%ld", (long)fs_type);
+                                    fprintf(out, "%ld", (long)fs_strategy);
                                     break;
                             } /* end switch */
                         } /* end else */
@@ -1003,6 +999,15 @@ H5_trace(const double *returning, const char *func, const char *type, ...)
                         } /* end else */
                         break;
 
+                    case 't':
+                        if(ptr) {
+                            if(vp)
+                                fprintf(out, "0x%lx", (unsigned long)vp);
+                            else
+                                fprintf(out, "NULL");
+                        } /* end if */
+                        break;
+
                     case 'v':
                         if(ptr) {
                             if(vp)
diff --git a/src/Makefile.am b/src/Makefile.am
index 69b54b4..59df4c2 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -60,7 +60,7 @@ libhdf5_la_SOURCES= H5.c H5checksum.c H5dbg.c H5system.c H5timer.c H5trace.c \
         H5F.c H5Fint.c H5Faccum.c H5Fcwfs.c \
         H5Fdbg.c H5Fdeprec.c H5Fefc.c H5Ffake.c H5Fio.c \
         H5Fmount.c H5Fquery.c \
-        H5Fsfile.c H5Fsuper.c H5Fsuper_cache.c H5Ftest.c \
+        H5Fsfile.c H5Fspace.c H5Fsuper.c H5Fsuper_cache.c H5Ftest.c \
         H5FA.c H5FAcache.c H5FAdbg.c H5FAdblock.c H5FAdblkpage.c H5FAhdr.c \
         H5FAint.c H5FAstat.c H5FAtest.c \
         H5FD.c H5FDcore.c  \
@@ -98,6 +98,7 @@ libhdf5_la_SOURCES= H5.c H5checksum.c H5dbg.c H5system.c H5timer.c H5trace.c \
         H5Pfapl.c H5Pfcpl.c H5Pfmpl.c \
         H5Pgcpl.c H5Pint.c \
         H5Plapl.c H5Plcpl.c H5Pocpl.c H5Pocpypl.c H5Pstrcpl.c H5Ptest.c \
+        H5PB.c \
         H5PL.c \
         H5R.c H5Rdeprec.c \
         H5UC.c \