[svn-r9402] Purpose:

    Port development branch changes to release branch.

Description:
    Initial step in bringing changes to support new metadata cache from the
development branch to the release branch.

Solution:
    This checkin just aligns the H5AC* API changes, as well as bringing back
various minor code cleanups, etc.

Platforms tested:
    FreeBSD 4.10 (sleipnir) w/parallel
    Solaris 2.7 (arabica)
    Linux 2.4 (verbena) w/FORTRAN

12 files changed, 234 insertions, 705 deletions

diff --git a/MANIFEST b/MANIFEST
index d8a0b90..5d20ef8 100644
--- a/MANIFEST
+++ b/MANIFEST
@@ -1147,9 +1147,13 @@
 ./src/H5Gpublic.h
 ./src/H5Gstab.c
 ./src/H5HG.c
+./src/H5HGdbg.c
+./src/H5HGpkg.h
 ./src/H5HGprivate.h
 ./src/H5HGpublic.h
 ./src/H5HL.c
+./src/H5HLdbg.c
+./src/H5HLpkg.h
 ./src/H5HLprivate.h
 ./src/H5HLpublic.h
 ./src/H5HP.c
diff --git a/src/H5AC.c b/src/H5AC.c
index d6c91eb..51c029a 100644
--- a/src/H5AC.c
+++ b/src/H5AC.c
@@ -466,231 +466,6 @@ done:
 
 
 /*-------------------------------------------------------------------------
- * Function:    H5AC_find
- *
- * Purpose:     Given an object type and the address at which that object
- *              is located in the file, return a pointer to the object.
- *              The optional UDATA1 and UDATA2 structures are passed down to
- *              the function that is responsible for loading the object into
- *              memory.
- *
- *              The returned pointer is guaranteed to be valid until the next
- *              call to an H5AC function (if you want a pointer which is valid
- *              indefinately then see H5AC_protect()).
- *
- *              If H5AC_DEBUG is defined then this function also
- *              checks that the requested object is not currently
- *              protected since it is illegal to modify a protected object
- *              except through the pointer returned by H5AC_protect().
- *
- * Return:      Success:        Pointer to the object.  The pointer is
- *                              valid until some other cache function
- *                              is called.
- *
- *              Failure:        NULL
- *
- * Programmer:  Robb Matzke
- *              matzke@llnl.gov
- *              Jul  9 1997
- *
- * Modifications:
- *
- *      Robb Matzke, 4 Aug 1997
- *      Fails immediately if the cached object is at the correct address
- *      but is of the wrong type.  This happens if the caller doesn't know
- *      what type of object is at the address and calls this function with
- *      various type identifiers until one succeeds (cf., the debugger).
- *
- *      Robb Matzke, 30 Oct 1997
- *      Keeps track of hits, misses, and flushes per object type so we have
- *      some cache performance diagnostics.
- *
- * 	Robb Matzke, 1999-07-27
- *	The ADDR argument is passed by value.
- *
- *-------------------------------------------------------------------------
- */
-void *
-H5AC_find(H5F_t *f, hid_t dxpl_id, const H5AC_class_t *type, haddr_t addr,
-	    const void *udata1, void *udata2)
-{
-    unsigned                idx;
-    void                   *thing;
-    H5AC_flush_func_t       flush;
-    H5AC_info_t           **info;
-#ifdef H5_HAVE_PARALLEL
-    H5AC_info_t           **dinfo = NULL;
-#endif /* H5_HAVE_PARALLEL */
-    H5AC_t                 *cache;
-    void                   *ret_value;          /* Return value */
-
-    FUNC_ENTER_NOAPI(H5AC_find, NULL);
-
-    assert(f);
-    assert(f->shared->cache);
-    assert(type);
-    assert(type->load);
-    assert(type->flush);
-    assert(H5F_addr_defined(addr));
-
-    /* Get local pointers to the file's cache information */
-    idx = H5AC_HASH(f, addr);
-    cache = f->shared->cache;
-    info = cache->slot + idx;
-
-#ifdef H5_HAVE_PARALLEL
-    /* If MPIO, MPIPOSIX, or FPHDF5 is used, do special parallel I/O actions */
-    if(IS_H5FD_MPI(f)) {
-        H5AC_dest_func_t        dest;
-
-        /* Get local pointer to file's dirty cache information */
-        dinfo = cache->dslot + idx;
-
-        /* Check if the cache has 'held' information for this cache slot */
-        if (*dinfo) {
-            /* Sanity check that the 'clean' item is really clean */
-            assert(*info);
-            assert((*info)->dirty==0);
-
-            /* Destroy 'current' information */
-            dest = (*info)->type->dest;
-            if ((dest)(f, (*info))<0)
-                HGOTO_ERROR(H5E_CACHE, H5E_CANTFREE, NULL, "unable to free cached object");
-
-            /* Restore 'held' information back to 'current' information */
-            (*info)=(*dinfo);
-
-            /* Clear 'held' information */
-            (*dinfo)=NULL;
-
-#ifdef H5AC_DEBUG
-            cache->diagnostics[type->id].nrestores++;
-#endif /* H5AC_DEBUG */
-        } /* end if */
-    } /* end if */
-#endif /* H5_HAVE_PARALLEL */
-
-    /*
-     * Return right away if the item is in the cache.
-     */
-    if ((*info) && H5F_addr_eq(addr,(*info)->addr)
-#ifdef H5AC_DEBUG
-            && (*info)->type==type
-#endif /* H5AC_DEBUG */
-            ) {
-#ifndef H5AC_DEBUG
-        /* Sanity check that the object in the cache is the correct type */
-        assert((*info)->type==type);
-#endif /* H5AC_DEBUG */
-
-#ifdef H5AC_DEBUG
-        cache->diagnostics[type->id].nhits++;
-#endif /* H5AC_DEBUG */
-        HGOTO_DONE(*info);
-    }
-#ifdef H5AC_DEBUG
-    cache->diagnostics[type->id].nmisses++;
-#endif /* H5AC_DEBUG */
-
-#ifdef H5AC_DEBUG
-    /*
-     * Check that the requested thing isn't protected, for protected things
-     * can only be modified through the pointer already handed out by the
-     * H5AC_protect() function.
-     */
-    {
-        H5AC_prot_t            *prot = NULL;
-        int                    i;
-
-        prot = cache->prot + idx;
-        for (i = 0; i < prot->nprots; i++) {
-            assert(H5F_addr_ne(addr, prot->slot[i]->addr));
-        }
-    }
-#endif /* H5AC_DEBUG */
-
-    /*
-     * Load a new thing.  If it can't be loaded, then return an error
-     * without preempting anything.
-     */
-    if (NULL == (thing = (type->load)(f, dxpl_id, addr, udata1, udata2)))
-        HGOTO_ERROR(H5E_CACHE, H5E_CANTLOAD, NULL, "unable to load object");
-
-#ifdef H5_HAVE_PARALLEL
-    /* If MPIO, MPIPOSIX, or FPHDF5 is used, do special parallel I/O actions */
-    if(IS_H5FD_MPI(f)) {
-        H5P_genplist_t *dxpl;           /* Dataset transfer property list */
-        H5FD_mpio_xfer_t xfer_mode;     /* I/O transfer mode property value */
-
-        /* Get the dataset transfer property list */
-        if (NULL == (dxpl = H5I_object(dxpl_id)))
-            HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, NULL, "not a dataset creation property list");
-
-        /* Get the transfer mode property */
-        if(H5P_get(dxpl, H5D_XFER_IO_XFER_MODE_NAME, &xfer_mode) < 0)
-            HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, NULL, "can't retrieve xfer mode");
-
-        /* Make certain there is no 'held' info for this slot */
-        assert((*dinfo)==NULL);
-
-        /* Must be using collective I/O to flush metadata in parallel */
-        if(xfer_mode==H5FD_MPIO_INDEPENDENT) {
-            /* Check if there is dirty metadata in this slot */
-            if((*info) && (*info)->dirty) {
-                /* 'Hold' the current metadata for later */
-                (*dinfo)=(*info);
-
-                /* Reset the 'current' metadata, so it doesn't get flushed */
-                (*info)=NULL;
-
-#ifdef H5AC_DEBUG
-                cache->diagnostics[(*dinfo)->type->id].nholds++;
-#endif /* H5AC_DEBUG */
-            } /* end if */
-        } /* end else */
-    } /* end if */
-#endif /* H5_HAVE_PARALLEL */
-
-    /*
-     * Flush & destroy the previous cache entry if there is one.
-     */
-    if (*info) {
-#ifdef H5AC_DEBUG
-        H5AC_subid_t type_id=(*info)->type->id;  /* Remember this for later */
-#endif /* H5AC_DEBUG */
-
-        flush = (*info)->type->flush;
-        if ( (flush)(f, dxpl_id, TRUE, (*info)->addr, (*info)) < 0) {
-            /*
-             * The old thing could not be removed from the stack.
-             * Release the new thing and fail.
-             */
-            if ((type->dest)(f, thing) < 0)
-                HGOTO_ERROR(H5E_CACHE, H5E_CANTFLUSH, NULL, "unable to destroy just-loaded object");
-            HGOTO_ERROR(H5E_CACHE, H5E_CANTFLUSH, NULL, "unable to flush existing cached object");
-        }
-#ifdef H5AC_DEBUG
-        cache->diagnostics[type_id].nflushes++;
-#endif /* H5AC_DEBUG */
-    } /* end if */
-
-    /*
-     * Make the cache point to the new thing.
-     */
-    (*info)=thing;
-    (*info)->type = type;
-    (*info)->addr = addr;
-    assert((*info)->dirty==0);  /* Should be clean after being loaded */
-
-    /* Set the return value */
-    ret_value=thing;
-
-done:
-    FUNC_LEAVE_NOAPI(ret_value);
-}
-
-
-/*-------------------------------------------------------------------------
  * Function:    H5AC_compare
  *
  * Purpose:     Compare two hash entries by address.  Unused entries are
@@ -1419,8 +1194,15 @@ done:
  *-------------------------------------------------------------------------
  */
 void *
-H5AC_protect(H5F_t *f, hid_t dxpl_id, const H5AC_class_t *type, haddr_t addr,
-	     const void *udata1, void *udata2)
+H5AC_protect(H5F_t *f, 
+             hid_t dxpl_id, 
+             const H5AC_class_t *type, 
+             haddr_t addr,
+	     const void *udata1, 
+             void *udata2, 
+             H5AC_protect_t
+             UNUSED
+             rw)
 {
     int                     idx;
     void                   *thing=NULL;
diff --git a/src/H5ACprivate.h b/src/H5ACprivate.h
index dbe4ec9..7491f18 100644
--- a/src/H5ACprivate.h
+++ b/src/H5ACprivate.h
@@ -29,7 +29,7 @@
 #ifndef _H5ACprivate_H
 #define _H5ACprivate_H
 
-#include "H5ACpublic.h"		/*public prototypes			     */
+#include "H5ACpublic.h"		/*public prototypes			*/
 
 /* Pivate headers needed by this header */
 #include "H5private.h"		/* Generic Functions			*/
@@ -101,6 +101,20 @@ typedef struct H5AC_info_t {
 } H5AC_info_t;
 typedef H5AC_info_t *H5AC_info_ptr_t;   /* Typedef for free lists */
 
+/*===----------------------------------------------------------------------===
+ *                             Protect Types
+ *===----------------------------------------------------------------------===
+ *
+ * These are for the wrapper functions to H5AC_protect. They specify what
+ * type of operation you're planning on doing to the metadata. The
+ * Flexible Parallel HDF5 locking can then act accordingly.
+ */
+
+typedef enum H5AC_protect_t {
+    H5AC_WRITE,                 /* Protect object for writing                */
+    H5AC_READ                   /* Protect object for reading                */
+} H5AC_protect_t;
+
 /* Typedef for metadata cache (defined in H5AC.c) */
 typedef struct H5AC_t H5AC_t;
 
@@ -135,12 +149,11 @@ H5_DLL herr_t H5AC_init(void);
 H5_DLL herr_t H5AC_create(H5F_t *f, int size_hint);
 H5_DLL herr_t H5AC_set(H5F_t *f, hid_t dxpl_id, const H5AC_class_t *type, haddr_t addr,
 			void *thing);
-H5_DLL void *H5AC_protect(H5F_t *f, hid_t dxpl_id, const H5AC_class_t *type, haddr_t addr,
-			   const void *udata1, void *udata2);
+H5_DLL void *H5AC_protect(H5F_t *f, hid_t dxpl_id, const H5AC_class_t *type,
+                          haddr_t addr, const void *udata1, void *udata2,
+                          H5AC_protect_t rw);
 H5_DLL herr_t H5AC_unprotect(H5F_t *f, hid_t dxpl_id, const H5AC_class_t *type, haddr_t addr,
 			      void *thing, hbool_t deleted);
-H5_DLL void *H5AC_find(H5F_t *f, hid_t dxpl_id, const H5AC_class_t *type,
-        haddr_t addr, const void *udata1, void *udata2);
 H5_DLL herr_t H5AC_flush(H5F_t *f, hid_t dxpl_id, const H5AC_class_t *type, haddr_t addr,
 			  unsigned flags);
 H5_DLL herr_t H5AC_rename(H5F_t *f, hid_t dxpl_id, const H5AC_class_t *type,
diff --git a/src/H5B.c b/src/H5B.c
index 2b74a29..d327858 100644
--- a/src/H5B.c
+++ b/src/H5B.c
@@ -630,7 +630,7 @@ H5B_find(H5F_t *f, hid_t dxpl_id, const H5B_class_t *type, haddr_t addr, void *u
      * Perform a binary search to locate the child which contains
      * the thing for which we're searching.
      */
-    if (NULL == (bt = H5AC_protect(f, dxpl_id, H5AC_BT, addr, type, udata)))
+    if (NULL == (bt = H5AC_protect(f, dxpl_id, H5AC_BT, addr, type, udata, H5AC_READ)))
 	HGOTO_ERROR(H5E_BTREE, H5E_CANTLOAD, FAIL, "unable to load B-tree node")
     shared=H5RC_GET_OBJ(bt->rc_shared);
     HDassert(shared);
@@ -806,7 +806,7 @@ H5B_split(H5F_t *f, hid_t dxpl_id, H5B_t *old_bt, haddr_t old_addr,
      */
     if (H5B_create(f, dxpl_id, shared->type, udata, new_addr_p/*out*/) < 0)
 	HGOTO_ERROR(H5E_BTREE, H5E_CANTINIT, FAIL, "unable to create B-tree")
-    if (NULL==(new_bt=H5AC_protect(f, dxpl_id, H5AC_BT, *new_addr_p, shared->type, udata)))
+    if (NULL==(new_bt=H5AC_protect(f, dxpl_id, H5AC_BT, *new_addr_p, shared->type, udata, H5AC_WRITE)))
 	HGOTO_ERROR(H5E_BTREE, H5E_CANTLOAD, FAIL, "unable to protect B-tree")
     new_bt->level = old_bt->level;
 
@@ -835,7 +835,7 @@ H5B_split(H5F_t *f, hid_t dxpl_id, H5B_t *old_bt, haddr_t old_addr,
     new_bt->right = old_bt->right;
 
     if (H5F_addr_defined(old_bt->right)) {
-	if (NULL == (tmp_bt = H5AC_protect(f, dxpl_id, H5AC_BT, old_bt->right, shared->type, udata)))
+	if (NULL == (tmp_bt = H5AC_protect(f, dxpl_id, H5AC_BT, old_bt->right, shared->type, udata, H5AC_WRITE)))
 	    HGOTO_ERROR(H5E_BTREE, H5E_CANTLOAD, FAIL, "unable to load right sibling")
 
 	tmp_bt->cache_info.dirty = TRUE;
@@ -921,7 +921,7 @@ H5B_insert(H5F_t *f, hid_t dxpl_id, const H5B_class_t *type, haddr_t addr,
     assert(H5B_INS_RIGHT == my_ins);
 
     /* the current root */
-    if (NULL == (bt = H5AC_protect(f, dxpl_id, H5AC_BT, addr, type, udata)))
+    if (NULL == (bt = H5AC_protect(f, dxpl_id, H5AC_BT, addr, type, udata, H5AC_READ)))
 	HGOTO_ERROR(H5E_BTREE, H5E_CANTLOAD, FAIL, "unable to locate root of B-tree")
     shared=H5RC_GET_OBJ(bt->rc_shared);
     HDassert(shared);
@@ -937,7 +937,7 @@ H5B_insert(H5F_t *f, hid_t dxpl_id, const H5B_class_t *type, haddr_t addr,
     bt = NULL;
     
     /* the new node */
-    if (NULL == (bt = H5AC_protect(f, dxpl_id, H5AC_BT, child, type, udata)))
+    if (NULL == (bt = H5AC_protect(f, dxpl_id, H5AC_BT, child, type, udata, H5AC_READ)))
 	HGOTO_ERROR(H5E_BTREE, H5E_CANTLOAD, FAIL, "unable to load new node")
 
     if (!rt_key_changed)
@@ -958,7 +958,7 @@ H5B_insert(H5F_t *f, hid_t dxpl_id, const H5B_class_t *type, haddr_t addr,
         HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, FAIL, "unable to allocate file space to move root")
 
     /* update the new child's left pointer */
-    if (NULL == (bt = H5AC_protect(f, dxpl_id, H5AC_BT, child, type, udata)))
+    if (NULL == (bt = H5AC_protect(f, dxpl_id, H5AC_BT, child, type, udata, H5AC_WRITE)))
         HGOTO_ERROR(H5E_BTREE, H5E_CANTLOAD, FAIL, "unable to load new child")
 
     bt->cache_info.dirty = TRUE;
@@ -974,7 +974,7 @@ H5B_insert(H5F_t *f, hid_t dxpl_id, const H5B_class_t *type, haddr_t addr,
      * at the new location -QAK
      */
     /* Bring the old root into the cache if it's not already */
-    if (NULL == (bt = H5AC_protect(f, dxpl_id, H5AC_BT, addr, type, udata)))
+    if (NULL == (bt = H5AC_protect(f, dxpl_id, H5AC_BT, addr, type, udata, H5AC_WRITE)))
         HGOTO_ERROR(H5E_BTREE, H5E_CANTLOAD, FAIL, "unable to load new child")
 
     /* Make certain the old root info is marked as dirty before moving it, */
@@ -1189,7 +1189,7 @@ H5B_insert_helper(H5F_t *f, hid_t dxpl_id, haddr_t addr, const H5B_class_t *type
      * data.  When the search completes IDX points to the child that
      * should get the new data.
      */
-    if (NULL == (bt = H5AC_protect(f, dxpl_id, H5AC_BT, addr, type, udata)))
+    if (NULL == (bt = H5AC_protect(f, dxpl_id, H5AC_BT, addr, type, udata, H5AC_WRITE)))
 	HGOTO_ERROR(H5E_BTREE, H5E_CANTLOAD, H5B_INS_ERROR, "unable to load node")
     shared=H5RC_GET_OBJ(bt->rc_shared);
     HDassert(shared);
@@ -1359,7 +1359,7 @@ H5B_insert_helper(H5F_t *f, hid_t dxpl_id, haddr_t addr, const H5B_class_t *type
 	if (bt->nchildren == shared->two_k) {
 	    if (H5B_split(f, dxpl_id, bt, addr, idx, udata, new_node_p/*out*/)<0)
 		HGOTO_ERROR(H5E_BTREE, H5E_CANTSPLIT, H5B_INS_ERROR, "unable to split node")
-	    if (NULL == (twin = H5AC_protect(f, dxpl_id, H5AC_BT, *new_node_p, type, udata)))
+	    if (NULL == (twin = H5AC_protect(f, dxpl_id, H5AC_BT, *new_node_p, type, udata, H5AC_WRITE)))
 		HGOTO_ERROR(H5E_BTREE, H5E_CANTLOAD, H5B_INS_ERROR, "unable to load node")
 	    if (idx<bt->nchildren) {
 		tmp_bt = bt;
@@ -1457,7 +1457,7 @@ H5B_iterate (H5F_t *f, hid_t dxpl_id, const H5B_class_t *type, H5B_operator_t op
     assert(H5F_addr_defined(addr));
     assert(udata);
 
-    if (NULL == (bt = H5AC_protect(f, dxpl_id, H5AC_BT, addr, type, udata)))
+    if (NULL == (bt = H5AC_protect(f, dxpl_id, H5AC_BT, addr, type, udata, H5AC_READ)))
 	HGOTO_ERROR(H5E_BTREE, H5E_CANTLOAD, FAIL, "unable to load B-tree node")
     shared=H5RC_GET_OBJ(bt->rc_shared);
     HDassert(shared);
@@ -1489,7 +1489,7 @@ H5B_iterate (H5F_t *f, hid_t dxpl_id, const H5B_class_t *type, H5B_operator_t op
 	     * leave the B-tree node protected during an application
 	     * callback.
 	     */
-	    if (NULL == (bt = H5AC_protect(f, dxpl_id, H5AC_BT, cur_addr, type, udata)))
+	    if (NULL == (bt = H5AC_protect(f, dxpl_id, H5AC_BT, cur_addr, type, udata, H5AC_READ)))
 		HGOTO_ERROR(H5E_BTREE, H5E_CANTLOAD, FAIL, "B-tree node")
 
             HDmemcpy(child, bt->child, bt->nchildren*sizeof(haddr_t));
@@ -1581,7 +1581,7 @@ H5B_remove_helper(H5F_t *f, hid_t dxpl_id, haddr_t addr, const H5B_class_t *type
      * Perform a binary search to locate the child which contains the thing
      * for which we're searching.
      */
-    if (NULL==(bt=H5AC_protect(f, dxpl_id, H5AC_BT, addr, type, udata)))
+    if (NULL==(bt=H5AC_protect(f, dxpl_id, H5AC_BT, addr, type, udata, H5AC_WRITE)))
 	HGOTO_ERROR(H5E_BTREE, H5E_CANTLOAD, H5B_INS_ERROR, "unable to load B-tree node")
     shared=H5RC_GET_OBJ(bt->rc_shared);
     HDassert(shared);
@@ -1663,7 +1663,7 @@ H5B_remove_helper(H5F_t *f, hid_t dxpl_id, haddr_t addr, const H5B_class_t *type
              */
             if (ret_value!=H5B_INS_REMOVE && level>0) {
                 if (H5F_addr_defined(bt->right)) {
-                    if (NULL == (sibling = H5AC_protect(f, dxpl_id, H5AC_BT, bt->right, type, udata)))
+                    if (NULL == (sibling = H5AC_protect(f, dxpl_id, H5AC_BT, bt->right, type, udata, H5AC_WRITE)))
                         HGOTO_ERROR(H5E_BTREE, H5E_CANTLOAD, H5B_INS_ERROR, "unable to unlink node from tree")
 
                     /* Make certain the native key for the right sibling is set up */
@@ -1694,7 +1694,7 @@ H5B_remove_helper(H5F_t *f, hid_t dxpl_id, haddr_t addr, const H5B_class_t *type
 	bt->nchildren = 0;
 	if (level>0) {
 	    if (H5F_addr_defined(bt->left)) {
-		if (NULL == (sibling = H5AC_protect(f, dxpl_id, H5AC_BT, bt->left, type, udata)))
+		if (NULL == (sibling = H5AC_protect(f, dxpl_id, H5AC_BT, bt->left, type, udata, H5AC_WRITE)))
 		    HGOTO_ERROR(H5E_BTREE, H5E_CANTLOAD, H5B_INS_ERROR, "unable to load node from tree")
 
 		sibling->right = bt->right;
@@ -1706,7 +1706,7 @@ H5B_remove_helper(H5F_t *f, hid_t dxpl_id, haddr_t addr, const H5B_class_t *type
                 sibling=NULL;   /* Make certain future references will be caught */
 	    }
 	    if (H5F_addr_defined(bt->right)) {
-		if (NULL == (sibling = H5AC_protect(f, dxpl_id, H5AC_BT, bt->right, type, udata)))
+		if (NULL == (sibling = H5AC_protect(f, dxpl_id, H5AC_BT, bt->right, type, udata, H5AC_WRITE)))
 		    HGOTO_ERROR(H5E_BTREE, H5E_CANTLOAD, H5B_INS_ERROR, "unable to unlink node from tree")
 
                 /* Copy left-most key from deleted node to left-most key in it's right neighbor */
@@ -1770,7 +1770,7 @@ H5B_remove_helper(H5F_t *f, hid_t dxpl_id, haddr_t addr, const H5B_class_t *type
          */
         if (level>0) {
             if (H5F_addr_defined(bt->right)) {
-                if (NULL == (sibling = H5AC_protect(f, dxpl_id, H5AC_BT, bt->right, type, udata)))
+                if (NULL == (sibling = H5AC_protect(f, dxpl_id, H5AC_BT, bt->right, type, udata, H5AC_WRITE)))
                     HGOTO_ERROR(H5E_BTREE, H5E_CANTLOAD, H5B_INS_ERROR, "unable to unlink node from tree")
 
                 HDmemcpy(H5B_NKEY(sibling,shared,0), H5B_NKEY(bt,shared,bt->nchildren), type->sizeof_nkey);
@@ -1864,7 +1864,7 @@ H5B_remove(H5F_t *f, hid_t dxpl_id, const H5B_class_t *type, haddr_t addr, void
      * If the B-tree is now empty then make sure we mark the root node as
      * being at level zero
      */
-    if (NULL == (bt = H5AC_protect(f, dxpl_id, H5AC_BT, addr, type, udata)))
+    if (NULL == (bt = H5AC_protect(f, dxpl_id, H5AC_BT, addr, type, udata, H5AC_WRITE)))
 	HGOTO_ERROR(H5E_BTREE, H5E_CANTLOAD, FAIL, "unable to load B-tree root node")
 
     if (0==bt->nchildren && 0!=bt->level) {
@@ -1916,7 +1916,7 @@ H5B_delete(H5F_t *f, hid_t dxpl_id, const H5B_class_t *type, haddr_t addr, void
     assert(H5F_addr_defined(addr));
 
     /* Lock this B-tree node into memory for now */
-    if (NULL == (bt = H5AC_protect(f, dxpl_id, H5AC_BT, addr, type, udata)))
+    if (NULL == (bt = H5AC_protect(f, dxpl_id, H5AC_BT, addr, type, udata, H5AC_WRITE)))
 	HGOTO_ERROR(H5E_BTREE, H5E_CANTLOAD, FAIL, "unable to load B-tree node")
     shared=H5RC_GET_OBJ(bt->rc_shared);
     HDassert(shared);
@@ -2119,7 +2119,7 @@ H5B_debug(H5F_t *f, hid_t dxpl_id, haddr_t addr, FILE *stream, int indent, int f
     /*
      * Load the tree node.
      */
-    if (NULL == (bt = H5AC_protect(f, dxpl_id, H5AC_BT, addr, type, udata)))
+    if (NULL == (bt = H5AC_protect(f, dxpl_id, H5AC_BT, addr, type, udata, H5AC_READ)))
 	HGOTO_ERROR(H5E_BTREE, H5E_CANTLOAD, FAIL, "unable to load B-tree node")
     shared=H5RC_GET_OBJ(bt->rc_shared);
     HDassert(shared);
@@ -2232,7 +2232,7 @@ H5B_assert(H5F_t *f, hid_t dxpl_id, haddr_t addr, const H5B_class_t *type, void
 	}
     }
     /* Initialize the queue */
-    bt = H5AC_protect(f, dxpl_id, H5AC_BT, addr, type, udata);
+    bt = H5AC_protect(f, dxpl_id, H5AC_BT, addr, type, udata, H5AC_READ);
     assert(bt);
     cur = H5MM_calloc(sizeof(struct child_t));
     assert (cur);
@@ -2251,7 +2251,7 @@ H5B_assert(H5F_t *f, hid_t dxpl_id, haddr_t addr, const H5B_class_t *type, void
      * test.
      */
     for (ncell = 0; cur; ncell++) {
-	bt = H5AC_protect(f, dxpl_id, H5AC_BT, cur->addr, type, udata);
+	bt = H5AC_protect(f, dxpl_id, H5AC_BT, cur->addr, type, udata, H5AC_READ);
 	assert(bt);
 
 	/* Check node header */
diff --git a/src/H5Gnode.c b/src/H5Gnode.c
index 4afc5f3..710de18 100644
--- a/src/H5Gnode.c
+++ b/src/H5Gnode.c
@@ -911,7 +911,7 @@ H5G_node_found(H5F_t *f, hid_t dxpl_id, haddr_t addr, const void UNUSED *_lt_key
     /*
      * Load the symbol table node for exclusive access.
      */
-    if (NULL == (sn = H5AC_protect(f, dxpl_id, H5AC_SNODE, addr, NULL, NULL)))
+    if (NULL == (sn = H5AC_protect(f, dxpl_id, H5AC_SNODE, addr, NULL, NULL, H5AC_READ)))
 	HGOTO_ERROR(H5E_SYM, H5E_CANTLOAD, FAIL, "unable to protect symbol table node");
 
     /* Get base address of heap */
@@ -1032,7 +1032,7 @@ H5G_node_insert(H5F_t *f, hid_t dxpl_id, haddr_t addr, void UNUSED *_lt_key,
     /*
      * Load the symbol node.
      */
-    if (NULL == (sn = H5AC_protect(f, dxpl_id, H5AC_SNODE, addr, NULL, NULL)))
+    if (NULL == (sn = H5AC_protect(f, dxpl_id, H5AC_SNODE, addr, NULL, NULL, H5AC_WRITE)))
 	HGOTO_ERROR(H5E_SYM, H5E_CANTLOAD, H5B_INS_ERROR, "unable to protect symbol table node");
 
     /* Get base address of heap */
@@ -1092,7 +1092,7 @@ H5G_node_insert(H5F_t *f, hid_t dxpl_id, haddr_t addr, void UNUSED *_lt_key,
 			    new_node_p/*out*/)<0)
 	    HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, H5B_INS_ERROR, "unable to split symbol table node");
 
-	if (NULL == (snrt = H5AC_protect(f, dxpl_id, H5AC_SNODE, *new_node_p, NULL, NULL)))
+	if (NULL == (snrt = H5AC_protect(f, dxpl_id, H5AC_SNODE, *new_node_p, NULL, NULL, H5AC_WRITE)))
 	    HGOTO_ERROR(H5E_SYM, H5E_CANTLOAD, H5B_INS_ERROR, "unable to split symbol table node");
 
 	HDmemcpy(snrt->entry, sn->entry + H5F_SYM_LEAF_K(f),
@@ -1215,7 +1215,7 @@ H5G_node_remove(H5F_t *f, hid_t dxpl_id, haddr_t addr, void *_lt_key/*in,out*/,
     assert(bt_udata);
 
     /* Load the symbol table */
-    if (NULL==(sn=H5AC_protect(f, dxpl_id, H5AC_SNODE, addr, NULL, NULL)))
+    if (NULL==(sn=H5AC_protect(f, dxpl_id, H5AC_SNODE, addr, NULL, NULL, H5AC_WRITE)))
 	HGOTO_ERROR(H5E_SYM, H5E_CANTLOAD, H5B_INS_ERROR, "unable to protect symbol table node");
 
     /* "Normal" removal of a single entry from the symbol table node */
@@ -1440,7 +1440,7 @@ H5G_node_iterate (H5F_t *f, hid_t dxpl_id, void UNUSED *_lt_key, haddr_t addr,
      * Save information about the symbol table node since we can't lock it
      * because we're about to call an application function.
      */
-    if (NULL == (sn = H5AC_protect(f, dxpl_id, H5AC_SNODE, addr, NULL, NULL)))
+    if (NULL == (sn = H5AC_protect(f, dxpl_id, H5AC_SNODE, addr, NULL, NULL, H5AC_READ)))
 	HGOTO_ERROR(H5E_SYM, H5E_CANTLOAD, H5B_ITER_ERROR, "unable to load symbol table node");
     nsyms = sn->nsyms;
     if (NULL==(name_off = H5MM_malloc (nsyms*sizeof(name_off[0]))))
@@ -1538,7 +1538,7 @@ H5G_node_sumup(H5F_t *f, hid_t dxpl_id, void UNUSED *_lt_key, haddr_t addr,
     assert(num_objs);
 
     /* Find the object node and add the number of symbol entries. */
-    if (NULL == (sn = H5AC_protect(f, dxpl_id, H5AC_SNODE, addr, NULL, NULL)))
+    if (NULL == (sn = H5AC_protect(f, dxpl_id, H5AC_SNODE, addr, NULL, NULL, H5AC_READ)))
 	HGOTO_ERROR(H5E_SYM, H5E_CANTLOAD, H5B_ITER_ERROR, "unable to load symbol table node");
 
     *num_objs += sn->nsyms;
@@ -1588,7 +1588,7 @@ H5G_node_name(H5F_t *f, hid_t dxpl_id, void UNUSED *_lt_key, haddr_t addr,
     assert(H5F_addr_defined(addr));
     assert(bt_udata);
 
-    if (NULL == (sn = H5AC_protect(f, dxpl_id, H5AC_SNODE, addr, NULL, NULL)))
+    if (NULL == (sn = H5AC_protect(f, dxpl_id, H5AC_SNODE, addr, NULL, NULL, H5AC_READ)))
 	HGOTO_ERROR(H5E_SYM, H5E_CANTLOAD, H5B_ITER_ERROR, "unable to load symbol table node");
     
     /* Find the node, locate the object symbol table entry and retrieve the name */ 
@@ -1653,7 +1653,7 @@ H5G_node_type(H5F_t *f, hid_t dxpl_id, void UNUSED *_lt_key, haddr_t addr,
     assert(bt_udata);
 
     /* Find the node, locate the object symbol table entry and retrieve the type */ 
-    if (NULL == (sn = H5AC_protect(f, dxpl_id, H5AC_SNODE, addr, NULL, NULL)))
+    if (NULL == (sn = H5AC_protect(f, dxpl_id, H5AC_SNODE, addr, NULL, NULL, H5AC_READ)))
 	HGOTO_ERROR(H5E_SYM, H5E_CANTLOAD, H5B_ITER_ERROR, "unable to load symbol table node");
 
     if(bt_udata->idx >= bt_udata->num_objs && bt_udata->idx < (bt_udata->num_objs+sn->nsyms)) {
@@ -1839,7 +1839,7 @@ H5G_node_debug(H5F_t *f, hid_t dxpl_id, haddr_t addr, FILE * stream, int indent,
      * If we couldn't load the symbol table node, then try loading the
      * B-tree node.
      */
-    if (NULL == (sn = H5AC_protect(f, dxpl_id, H5AC_SNODE, addr, NULL, NULL))) {
+    if (NULL == (sn = H5AC_protect(f, dxpl_id, H5AC_SNODE, addr, NULL, NULL, H5AC_READ))) {
         H5G_bt_ud1_t	udata;		/*data to pass through B-tree	*/
 
 	H5E_clear(); /*discard that error */
diff --git a/src/H5HG.c b/src/H5HG.c
index d79bb35..31bc709 100644
--- a/src/H5HG.c
+++ b/src/H5HG.c
@@ -37,6 +37,7 @@
  */
 
 #define H5F_PACKAGE		/*suppress error about including H5Fpkg	  */
+#define H5HG_PACKAGE		/*suppress error about including H5HGpkg	  */
 
 /* Pablo information */
 /* (Put before include files to avoid problems with inline functions) */
@@ -47,7 +48,7 @@
 #include "H5Eprivate.h"		/* Error handling		  	*/
 #include "H5Fpkg.h"             /* File access				*/
 #include "H5FLprivate.h"	/* Free lists                           */
-#include "H5HGprivate.h"	/* Global heaps				*/
+#include "H5HGpkg.h"		/* Global heaps				*/
 #include "H5MFprivate.h"	/* File memory management		*/
 #include "H5MMprivate.h"	/* Memory management			*/
 
@@ -59,17 +60,6 @@
 #define H5HG_VERSION	1
 
 /*
- * Pad all global heap messages to a multiple of eight bytes so we can load
- * the entire collection into memory and operate on it there.  Eight should
- * be sufficient for machines that have alignment constraints because our
- * largest data type is eight bytes.
- */
-#define H5HG_ALIGNMENT	8
-#define H5HG_ALIGN(X)	(H5HG_ALIGNMENT*(((X)+H5HG_ALIGNMENT-1)/	      \
-					 H5HG_ALIGNMENT))
-#define H5HG_ISALIGNED(X) ((X)==H5HG_ALIGN(X))
-
-/*
  * All global heap collections are at least this big.  This allows us to read
  * most collections with a single read() since we don't have to read a few
  * bytes of header to figure out the size.  If the heap is larger than this
@@ -111,16 +101,6 @@
 	       H5F_SIZEOF_SIZE(f))	/*collection size	*/
 
 /*
- * The overhead associated with each object in the heap, always a multiple of
- * the alignment so that the stuff that follows the header is aligned.
- */
-#define H5HG_SIZEOF_OBJHDR(f)						      \
-    H5HG_ALIGN(2 +			/*object id number	*/	      \
-	       2 +			/*reference count	*/	      \
-	       4 +			/*reserved		*/	      \
-	       H5F_SIZEOF_SIZE(f))	/*object data size	*/
-
-/*
  * The initial guess for the number of messages in a collection.  We assume
  * that all objects in that collection are zero length, giving the maximum
  * possible number of objects in the collection.  The collection itself has
@@ -139,28 +119,8 @@
 
 /* Private typedefs */
 
-typedef struct H5HG_obj_t {
-    int		nrefs;		/*reference count		*/
-    size_t		size;		/*total size of object		*/
-    uint8_t		*begin;		/*ptr to object into heap->chunk*/
-} H5HG_obj_t;
-
-struct H5HG_heap_t {
-    H5AC_info_t cache_info; /* Information for H5AC cache functions, _must_ be */
-                            /* first field in structure */
-    haddr_t		addr;		/*collection address		*/
-    size_t		size;		/*total size of collection	*/
-    uint8_t		*chunk;		/*the collection, incl. header	*/
-    size_t		nalloc;		/*numb object slots allocated	*/
-    size_t		nused;		/*number of slots used		*/
-                                        /* If this value is >65535 then all indices */
-                                        /* have been used at some time and the */
-                                        /* correct new index should be searched for */
-    H5HG_obj_t	*obj;		/*array of object descriptions	*/
-};
-
 /* PRIVATE PROTOTYPES */
-static H5HG_heap_t *H5HG_create(H5F_t *f, hid_t dxpl_id, size_t size);
+static haddr_t H5HG_create(H5F_t *f, hid_t dxpl_id, size_t size);
 #ifdef NOT_YET
 static void *H5HG_peek(H5F_t *f, hid_t dxpl_id, H5HG_t *hobj);
 #endif /* NOT_YET */
@@ -176,7 +136,7 @@ static herr_t H5HG_clear(H5HG_heap_t *heap);
 /*
  * H5HG inherits cache-like properties from H5AC
  */
-static const H5AC_class_t H5AC_GHEAP[1] = {{
+const H5AC_class_t H5AC_GHEAP[1] = {{
     H5AC_GHEAP_ID,
     (H5AC_load_func_t)H5HG_load,
     (H5AC_flush_func_t)H5HG_flush,
@@ -217,18 +177,27 @@ H5FL_BLK_DEFINE_STATIC(heap_chunk);
  *
  * Modifications:
  *
+ *		John Mainzer 5/26/04
+ *		Modified function to return the disk address of the new
+ *		global heap collection, or HADDR_UNDEF on failure.  This
+ *		is necessary, as in some cases (i.e. flexible parallel)
+ *		H5AC_set() will imediately flush and destroy the in memory 
+ *		version of the new collection.  For the same reason, I 
+ *		moved the code which places the new collection on the cwfs
+ *		list to just before the call to H5AC_set().
+ *
  *-------------------------------------------------------------------------
  */
-static H5HG_heap_t *
+static haddr_t 
 H5HG_create (H5F_t *f, hid_t dxpl_id, size_t size)
 {
     H5HG_heap_t	*heap = NULL;
-    H5HG_heap_t	*ret_value = NULL;
+    haddr_t	ret_value = HADDR_UNDEF;
     uint8_t	*p = NULL;
     haddr_t	addr;
     size_t	n;
     
-    FUNC_ENTER_NOAPI(H5HG_create, NULL);
+    FUNC_ENTER_NOAPI(H5HG_create, HADDR_UNDEF);
 
     /* Check args */
     assert (f);
@@ -238,22 +207,27 @@ H5HG_create (H5F_t *f, hid_t dxpl_id, size_t size)
 
     /* Create it */
     H5_CHECK_OVERFLOW(size,size_t,hsize_t);
-    if (HADDR_UNDEF==(addr=H5MF_alloc(f, H5FD_MEM_GHEAP, dxpl_id, (hsize_t)size)))
-	HGOTO_ERROR (H5E_HEAP, H5E_CANTINIT, NULL, "unable to allocate file space for global heap");
+    if ( HADDR_UNDEF==
+         (addr=H5MF_alloc(f, H5FD_MEM_GHEAP, dxpl_id, (hsize_t)size)))
+	HGOTO_ERROR (H5E_HEAP, H5E_CANTINIT, HADDR_UNDEF, \
+                     "unable to allocate file space for global heap");
     if (NULL==(heap = H5FL_MALLOC (H5HG_heap_t)))
-	HGOTO_ERROR (H5E_RESOURCE, H5E_NOSPACE, NULL, "memory allocation failed");
+	HGOTO_ERROR (H5E_RESOURCE, H5E_NOSPACE, HADDR_UNDEF, \
+                     "memory allocation failed");
     heap->addr = addr;
     heap->size = size;
     heap->cache_info.dirty = TRUE;
     if (NULL==(heap->chunk = H5FL_BLK_MALLOC (heap_chunk,size)))
-	HGOTO_ERROR (H5E_RESOURCE, H5E_NOSPACE, NULL, "memory allocation failed");
+	HGOTO_ERROR (H5E_RESOURCE, H5E_NOSPACE, HADDR_UNDEF, \
+                     "memory allocation failed");
 #ifdef H5_USING_PURIFY
 HDmemset(heap->chunk,0,size);
 #endif /* H5_USING_PURIFY */
     heap->nalloc = H5HG_NOBJS (f, size);
     heap->nused = 1; /* account for index 0, which is used for the free object */
     if (NULL==(heap->obj = H5FL_SEQ_MALLOC (H5HG_obj_t,heap->nalloc)))
-	HGOTO_ERROR (H5E_RESOURCE, H5E_NOSPACE, NULL, "memory allocation failed");
+	HGOTO_ERROR (H5E_RESOURCE, H5E_NOSPACE, HADDR_UNDEF, \
+                     "memory allocation failed");
 
     /* Initialize the header */
     HDmemcpy (heap->chunk, H5HG_MAGIC, H5HG_SIZEOF_MAGIC);
@@ -290,32 +264,37 @@ HDmemset(heap->chunk,0,size);
     HDmemset (p, 0, (size_t)((heap->chunk+heap->size) - p));
 #endif /* OLD_WAY */
 
-    /* Add the heap to the cache */
-    if (H5AC_set (f, dxpl_id, H5AC_GHEAP, addr, heap)<0)
-	HGOTO_ERROR (H5E_HEAP, H5E_CANTINIT, NULL, "unable to cache global heap collection");
-
     /* Add this heap to the beginning of the CWFS list */
     if (NULL==f->shared->cwfs) {
 	f->shared->cwfs = H5MM_malloc (H5HG_NCWFS * sizeof(H5HG_heap_t*));
 	if (NULL==(f->shared->cwfs))
-	    HGOTO_ERROR (H5E_RESOURCE, H5E_NOSPACE, NULL, "memory allocation failed");
+	    HGOTO_ERROR (H5E_RESOURCE, H5E_NOSPACE, HADDR_UNDEF, \
+                         "memory allocation failed");
 	f->shared->cwfs[0] = heap;
 	f->shared->ncwfs = 1;
     } else {
-	HDmemmove (f->shared->cwfs+1, f->shared->cwfs, MIN (f->shared->ncwfs, H5HG_NCWFS-1)*sizeof(H5HG_heap_t*));
+	HDmemmove (f->shared->cwfs+1, f->shared->cwfs, 
+                   MIN (f->shared->ncwfs, H5HG_NCWFS-1)*sizeof(H5HG_heap_t*));
 	f->shared->cwfs[0] = heap;
 	f->shared->ncwfs = MIN (H5HG_NCWFS, f->shared->ncwfs+1);
     }
 
-    ret_value = heap;
+    /* Add the heap to the cache */
+    if (H5AC_set (f, dxpl_id, H5AC_GHEAP, addr, heap)<0)
+	HGOTO_ERROR (H5E_HEAP, H5E_CANTINIT, HADDR_UNDEF, \
+                     "unable to cache global heap collection");
+
+    ret_value = addr;
 
 done:
-    if (!ret_value && heap) {
-        if(H5HG_dest(f,heap)<0)
-	    HDONE_ERROR(H5E_HEAP, H5E_CANTFREE, NULL, "unable to destroy global heap collection");
+    if ( ! ( H5F_addr_defined(addr) ) && heap) {
+        if ( H5HG_dest(f,heap) < 0 )
+	    HDONE_ERROR(H5E_HEAP, H5E_CANTFREE, HADDR_UNDEF, \
+                        "unable to destroy global heap collection");
     }
+
     FUNC_LEAVE_NOAPI(ret_value);
-}
+} /* H5HG_create() */
 
 
 /*-------------------------------------------------------------------------
@@ -858,6 +837,23 @@ done:
  *
  * Modifications:
  *
+ *		John Mainzer -- 5/24/04
+ *		The function used to modify the heap without protecting
+ *		the relevant collection first.  I did a half assed job
+ *		of fixing the problem, which should hold until we try to
+ *		support multi-threading.  At that point it will have to
+ *		be done right.
+ *
+ *		See in line comment of this date for more details.
+ *
+ *		John Mainzer - 5/26/04
+ *		Modified H5HG_create() to return the disk address of the
+ *		new collection, instead of the address of its 
+ *		representation in core.  This was necessary as in FP
+ *		mode, the cache will immediately flush and destroy any
+ *		entry inserted in it via H5AC_set().  I then modified
+ *		this function to account for the change in H5HG_create().
+ *
  *-------------------------------------------------------------------------
  */
 herr_t
@@ -866,6 +862,7 @@ H5HG_insert (H5F_t *f, hid_t dxpl_id, size_t size, void *obj, H5HG_t *hobj/*out*
     size_t	need;		/*total space needed for object		*/
     int	cwfsno;
     unsigned	idx;
+    haddr_t	addr = HADDR_UNDEF;
     H5HG_heap_t	*heap = NULL;
     hbool_t     found=0;        /* Flag to indicate a heap with enough space was found */
     herr_t      ret_value=SUCCEED;       /* Return value */
@@ -882,8 +879,35 @@ H5HG_insert (H5F_t *f, hid_t dxpl_id, size_t size, void *obj, H5HG_t *hobj/*out*
 
     /* Find a large enough collection on the CWFS list */
     need = H5HG_SIZEOF_OBJHDR(f) + H5HG_ALIGN(size);
+
+    /* Note that we don't have metadata cache locks on the entries in 
+     * f->shared->cwfs.  
+     *
+     * In the current situation, this doesn't matter, as we are single
+     * threaded, and as best I can tell, entries are added to and deleted 
+     * from f->shared->cwfs as they are added to and deleted from the 
+     * metadata cache.
+     *
+     * To be proper, we should either lock each entry in f->shared->cwfs
+     * as we examine it, or lock the whole array.  However, at present 
+     * I don't see the point as there will be significant overhead,
+     * and protecting and unprotecting all the collections in the global 
+     * heap on a regular basis will skew the replacement policy.
+     *
+     * However, there is a bigger issue -- as best I can tell, we only look 
+     * for free space in global heap chunks that are in cache.  If we can't 
+     * find any, we allocate a new chunk.  This may be a problem in FP mode,
+     * as the metadata cache is disabled.  Do we allocate a new heap 
+     * collection for every entry in this case?
+     *
+     * Note that all this comes from a cursory read of the source.  Don't
+     * take any of it as gospel.
+     *                                        JRM - 5/24/04
+     */
+
     for (cwfsno=0; cwfsno<f->shared->ncwfs; cwfsno++) {
 	if (f->shared->cwfs[cwfsno]->obj[0].size>=need) {
+	    addr = f->shared->cwfs[cwfsno]->addr;
             found=1;
 	    break;
 	} /* end if */
@@ -901,9 +925,10 @@ H5HG_insert (H5F_t *f, hid_t dxpl_id, size_t size, void *obj, H5HG_t *hobj/*out*
             new_need -= f->shared->cwfs[cwfsno]->obj[0].size;
             new_need = MAX(f->shared->cwfs[cwfsno]->size, new_need);
 
-            if((f->shared->cwfs[cwfsno]->size+new_need)<=H5HG_MAXSIZE && H5MF_can_extend(f,H5FD_MEM_GHEAP,f->shared->cwfs[cwfsno]->addr,(hsize_t)f->shared->cwfs[cwfsno]->size,(hsize_t)need)) {
+            if((f->shared->cwfs[cwfsno]->size+new_need)<=H5HG_MAXSIZE && H5MF_can_extend(f,H5FD_MEM_GHEAP,f->shared->cwfs[cwfsno]->addr,(hsize_t)f->shared->cwfs[cwfsno]->size,(hsize_t)new_need)) {
                 if(H5HG_extend(f,f->shared->cwfs[cwfsno],size)<0)
                     HGOTO_ERROR (H5E_HEAP, H5E_CANTINIT, FAIL, "unable to extend global heap collection");
+	        addr = f->shared->cwfs[cwfsno]->addr;
                 found=1;
                 break;
             } /* end if */
@@ -915,18 +940,19 @@ H5HG_insert (H5F_t *f, hid_t dxpl_id, size_t size, void *obj, H5HG_t *hobj/*out*
      * new collection large enough for the message plus the collection header.
      */
     if (!found) {
-	if (NULL==(heap=H5HG_create (f, dxpl_id, need+H5HG_SIZEOF_HDR (f))))
-	    HGOTO_ERROR (H5E_HEAP, H5E_CANTINIT, FAIL, "unable to allocate a global heap collection");
-	assert (f->shared->ncwfs>0);
-	assert (f->shared->cwfs[0]==heap);
-	assert (f->shared->cwfs[0]->obj[0].size >= need);
+
+        addr = H5HG_create(f, dxpl_id, need+H5HG_SIZEOF_HDR (f));
+
+        if ( ! H5F_addr_defined(addr) )
+	    HGOTO_ERROR (H5E_HEAP, H5E_CANTINIT, FAIL, \
+                         "unable to allocate a global heap collection");
 	cwfsno = 0;
     } /* end if */
     else {
-        /* Found a heap with enough space */
-        heap = f->shared->cwfs[cwfsno];
 
-        /* Move the collection forward in the CWFS list, if it's not already at the front */
+        /* Move the collection forward in the CWFS list, if it's not 
+         * already at the front 
+         */
         if (cwfsno>0) {
             H5HG_heap_t *tmp = f->shared->cwfs[cwfsno];
             f->shared->cwfs[cwfsno] = f->shared->cwfs[cwfsno-1];
@@ -934,7 +960,12 @@ H5HG_insert (H5F_t *f, hid_t dxpl_id, size_t size, void *obj, H5HG_t *hobj/*out*
             --cwfsno;
         } /* end if */
     } /* end else */
+
+    HDassert(H5F_addr_defined(addr));
     
+    if ( NULL == (heap = H5AC_protect(f, dxpl_id, H5AC_GHEAP, addr, NULL, NULL, H5AC_WRITE)) )
+        HGOTO_ERROR (H5E_HEAP, H5E_CANTLOAD, FAIL, "unable to load heap");
+
     /* Split the free space to make room for the new object */
     idx = H5HG_alloc (f, heap, size);
     assert (idx>0);
@@ -955,73 +986,12 @@ H5HG_insert (H5F_t *f, hid_t dxpl_id, size_t size, void *obj, H5HG_t *hobj/*out*
     hobj->idx = idx;
 
 done:
-    FUNC_LEAVE_NOAPI(ret_value);
-}
-
-#ifdef NOT_YET
-
-/*-------------------------------------------------------------------------
- * Function:	H5HG_peek
- *
- * Purpose:	Given an ID for a global heap object return a pointer to the
- *		beginning of that object.  This is intended for quick and
- *		dirty access to the object; otherwise use H5HG_read().
- *
- * Return:	Success:	Ptr directly into the H5AC layer for the
- *				specified object of the global heap.  The
- *				pointer is guaranteed to be valid only until
- *				some other hdf5 library function is called.
- *
- *		Failure:	NULL
- *
- * Programmer:	Robb Matzke
- *              Monday, March 30, 1998
- *
- * Modifications:
- *
- *-------------------------------------------------------------------------
- */
-static void *
-H5HG_peek (H5F_t *f, hid_t dxpl_id, H5HG_t *hobj)
-{
-    H5HG_heap_t	*heap = NULL;
-    void	*ret_value;
-    int	i;
-    
-    FUNC_ENTER_NOAPI(H5HG_peek, NULL);
-
-    /* Check args */
-    assert (f);
-    assert (hobj);
+    if ( heap && H5AC_unprotect(f, dxpl_id, H5AC_GHEAP, heap->addr, heap, FALSE) < 0 )
+        HDONE_ERROR(H5E_HEAP, H5E_PROTECT, FAIL, "unable to unprotect heap.");
 
-    /* Load the heap and return a pointer to the object */
-    if (NULL==(heap=H5AC_find(f, dxpl_id, H5AC_GHEAP, hobj->addr, NULL, NULL)))
-	HGOTO_ERROR (H5E_HEAP, H5E_CANTLOAD, NULL, "unable to load heap");
-
-    assert (hobj->idx>0 && hobj->idx<heap->nused);
-    ret_value = heap->obj[hobj->idx].begin + H5HG_SIZEOF_OBJHDR (f);
-    assert (ret_value);
-
-    /*
-     * Advance the heap in the CWFS list.  We might have done this already
-     * with the H5AC_find(), but it won't hurt to do it twice.
-     */
-    if (heap->obj[0].begin) {
-	for (i=0; i<f->shared->ncwfs; i++) {
-	    if (f->shared->cwfs[i]==heap) {
-		if (i) {
-		    f->shared->cwfs[i] = f->shared->cwfs[i-1];
-		    f->shared->cwfs[i-1] = heap;
-		}
-		break;
-	    }
-	}
-    }
-
-done:
     FUNC_LEAVE_NOAPI(ret_value);
-}
-#endif /* NOT_YET */
+
+} /* H5HG_insert() */
 
 
 /*-------------------------------------------------------------------------
@@ -1059,7 +1029,7 @@ H5HG_read (H5F_t *f, hid_t dxpl_id, H5HG_t *hobj, void *object/*out*/)
     assert (hobj);
 
     /* Load the heap */
-    if (NULL==(heap=H5AC_find(f, dxpl_id, H5AC_GHEAP, hobj->addr, NULL, NULL)))
+    if (NULL == (heap = H5AC_protect(f, dxpl_id, H5AC_GHEAP, hobj->addr, NULL, NULL, H5AC_READ)))
 	HGOTO_ERROR (H5E_HEAP, H5E_CANTLOAD, NULL, "unable to load heap");
 
     assert (hobj->idx>0 && hobj->idx<heap->nused);
@@ -1071,8 +1041,8 @@ H5HG_read (H5F_t *f, hid_t dxpl_id, H5HG_t *hobj, void *object/*out*/)
     HDmemcpy (object, p, size);
 
     /*
-     * Advance the heap in the CWFS list.  We might have done this already
-     * with the H5AC_find(), but it won't hurt to do it twice.
+     * Advance the heap in the CWFS list. We might have done this already
+     * with the H5AC_protect(), but it won't hurt to do it twice.
      */
     if (heap->obj[0].begin) {
 	for (i=0; i<f->shared->ncwfs; i++) {
@@ -1090,6 +1060,9 @@ H5HG_read (H5F_t *f, hid_t dxpl_id, H5HG_t *hobj, void *object/*out*/)
     ret_value=object;
 
 done:
+    if (heap && H5AC_unprotect(f, dxpl_id, H5AC_GHEAP, hobj->addr, heap, FALSE)<0)
+        HDONE_ERROR(H5E_HEAP, H5E_PROTECT, NULL, "unable to release object header");
+
     FUNC_LEAVE_NOAPI(ret_value);
 }
 
@@ -1128,23 +1101,28 @@ H5HG_link (H5F_t *f, hid_t dxpl_id, const H5HG_t *hobj, int adjust)
     if (0==(f->intent & H5F_ACC_RDWR))
 	HGOTO_ERROR (H5E_HEAP, H5E_WRITEERROR, FAIL, "no write intent on file");
 
-    /* Load the heap */
-    if (NULL==(heap=H5AC_find(f, dxpl_id, H5AC_GHEAP, hobj->addr, NULL, NULL)))
-	HGOTO_ERROR (H5E_HEAP, H5E_CANTLOAD, FAIL, "unable to load heap");
-    assert (hobj->idx>0 && hobj->idx<heap->nused);
-    assert (heap->obj[hobj->idx].begin);
-    if (heap->obj[hobj->idx].nrefs+adjust<0)
-	HGOTO_ERROR (H5E_HEAP, H5E_BADRANGE, FAIL, "new link count would be out of range");
-    if (heap->obj[hobj->idx].nrefs+adjust>H5HG_MAXLINK)
-	HGOTO_ERROR (H5E_HEAP, H5E_BADVALUE, FAIL, "new link count would be out of range");
-    heap->obj[hobj->idx].nrefs += adjust;
-    if (adjust)
+    if(adjust!=0) {
+        /* Load the heap */
+        if (NULL == (heap = H5AC_protect(f, dxpl_id, H5AC_GHEAP, hobj->addr, NULL, NULL, H5AC_WRITE)))
+            HGOTO_ERROR(H5E_HEAP, H5E_CANTLOAD, FAIL, "unable to load heap");
+
+        assert (hobj->idx>0 && hobj->idx<heap->nused);
+        assert (heap->obj[hobj->idx].begin);
+        if (heap->obj[hobj->idx].nrefs+adjust<0)
+            HGOTO_ERROR (H5E_HEAP, H5E_BADRANGE, FAIL, "new link count would be out of range");
+        if (heap->obj[hobj->idx].nrefs+adjust>H5HG_MAXLINK)
+            HGOTO_ERROR (H5E_HEAP, H5E_BADVALUE, FAIL, "new link count would be out of range");
+        heap->obj[hobj->idx].nrefs += adjust;
         heap->cache_info.dirty = TRUE;
+    } /* end if */
 
     /* Set return value */
     ret_value=heap->obj[hobj->idx].nrefs;
 
 done:
+    if (heap && H5AC_unprotect(f, dxpl_id, H5AC_GHEAP, hobj->addr, heap, FALSE)<0)
+        HDONE_ERROR(H5E_HEAP, H5E_PROTECT, FAIL, "unable to release object header");
+
     FUNC_LEAVE_NOAPI(ret_value);
 }
 
@@ -1171,6 +1149,7 @@ H5HG_remove (H5F_t *f, hid_t dxpl_id, H5HG_t *hobj)
     size_t	need;
     int	i;
     unsigned	u;
+    hbool_t     deleted=FALSE;          /* Whether the heap gets deleted */
     herr_t      ret_value=SUCCEED;       /* Return value */
     
     FUNC_ENTER_NOAPI(H5HG_remove, FAIL);
@@ -1182,8 +1161,9 @@ H5HG_remove (H5F_t *f, hid_t dxpl_id, H5HG_t *hobj)
         HGOTO_ERROR (H5E_HEAP, H5E_WRITEERROR, FAIL, "no write intent on file");
 
     /* Load the heap */
-    if (NULL==(heap=H5AC_find(f, dxpl_id, H5AC_GHEAP, hobj->addr, NULL, NULL)))
-        HGOTO_ERROR (H5E_HEAP, H5E_CANTLOAD, FAIL, "unable to load heap");
+    if (NULL == (heap = H5AC_protect(f, dxpl_id, H5AC_GHEAP, hobj->addr, NULL, NULL, H5AC_WRITE)))
+        HGOTO_ERROR(H5E_HEAP, H5E_CANTLOAD, FAIL, "unable to load heap");
+
     assert (hobj->idx>0 && hobj->idx<heap->nused);
     assert (heap->obj[hobj->idx].begin);
     obj_start = heap->obj[hobj->idx].begin;
@@ -1222,12 +1202,11 @@ H5HG_remove (H5F_t *f, hid_t dxpl_id, H5HG_t *hobj)
         heap->cache_info.dirty = FALSE;
         H5_CHECK_OVERFLOW(heap->size,size_t,hsize_t);
         H5MF_xfree(f, H5FD_MEM_GHEAP, dxpl_id, heap->addr, (hsize_t)heap->size);
-        H5AC_flush (f, dxpl_id, H5AC_GHEAP, heap->addr, H5F_FLUSH_INVALIDATE);
-        heap = NULL;
+        deleted=TRUE;   /* Indicate that the object was deleted, for the unprotect call */
     } else {
         /*
          * If the heap is in the CWFS list then advance it one position.  The
-         * H5AC_find() might have done that too, but that's okay.  If the
+         * H5AC_protect() might have done that too, but that's okay.  If the
          * heap isn't on the CWFS list then add it to the end.
          */
         for (i=0; i<f->shared->ncwfs; i++) {
@@ -1236,7 +1215,7 @@ H5HG_remove (H5F_t *f, hid_t dxpl_id, H5HG_t *hobj)
                     f->shared->cwfs[i] = f->shared->cwfs[i-1];
                     f->shared->cwfs[i-1] = heap;
                 }
-            break;
+                break;
             }
         }
         if (i>=f->shared->ncwfs) {
@@ -1246,106 +1225,9 @@ H5HG_remove (H5F_t *f, hid_t dxpl_id, H5HG_t *hobj)
     }
     
 done:
-    FUNC_LEAVE_NOAPI(ret_value);
-}
-
-
-/*-------------------------------------------------------------------------
- * Function:	H5HG_debug
- *
- * Purpose:	Prints debugging information about a global heap collection.
- *
- * Return:	Non-negative on success/Negative on failure
- *
- * Programmer:	Robb Matzke
- *		matzke@llnl.gov
- *		Mar 27, 1998
- *
- * Modifications:
- *		Robb Matzke, 1999-07-28
- *		The ADDR argument is passed by value.
- *
- *              Robb Matzke, LLNL, 2003-06-05
- *              The size does not include the object header, just the data.
- *-------------------------------------------------------------------------
- */
-herr_t
-H5HG_debug(H5F_t *f, hid_t dxpl_id, haddr_t addr, FILE *stream, int indent,
-	  int fwidth)
-{
-    unsigned		u, nused, maxobj;
-    unsigned		j, k;
-    H5HG_heap_t		*h = NULL;
-    char		buf[64];
-    uint8_t		*p = NULL;
-    herr_t      ret_value=SUCCEED;       /* Return value */
+    if (heap && H5AC_unprotect(f, dxpl_id, H5AC_GHEAP, hobj->addr, heap, deleted) != SUCCEED)
+        HDONE_ERROR(H5E_HEAP, H5E_PROTECT, FAIL, "unable to release object header");
 
-    FUNC_ENTER_NOAPI(H5HG_debug, FAIL);
-
-    /* check arguments */
-    assert(f);
-    assert(H5F_addr_defined (addr));
-    assert(stream);
-    assert(indent >= 0);
-    assert(fwidth >= 0);
-
-    if (NULL == (h = H5AC_find(f, dxpl_id, H5AC_GHEAP, addr, NULL, NULL)))
-	HGOTO_ERROR(H5E_HEAP, H5E_CANTLOAD, FAIL, "unable to load global heap collection");
-    fprintf(stream, "%*sGlobal Heap Collection...\n", indent, "");
-    fprintf(stream, "%*s%-*s %d\n", indent, "", fwidth,
-	    "Dirty:",
-	    (int)(h->cache_info.dirty));
-    fprintf(stream, "%*s%-*s %lu\n", indent, "", fwidth,
-	    "Total collection size in file:",
-	    (unsigned long)(h->size));
-
-    for (u=1, nused=0, maxobj=0; u<h->nalloc; u++) {
-	if (h->obj[u].begin) {
-	    nused++;
-	    if (u>maxobj) maxobj = u;
-	}
-    }
-    fprintf (stream, "%*s%-*s %u/%lu/", indent, "", fwidth,
-	     "Objects defined/allocated/max:",
-	     nused, (unsigned long)h->nalloc);
-    fprintf (stream, nused ? "%u\n": "NA\n", maxobj);
-
-    fprintf (stream, "%*s%-*s %lu\n", indent, "", fwidth,
-	     "Free space:",
-	     (unsigned long)(h->obj[0].size));
-
-    for (u=1; u<h->nalloc; u++) {
-	if (h->obj[u].begin) {
-	    sprintf (buf, "Object %u", u);
-	    fprintf (stream, "%*s%s\n", indent, "", buf);
-	    fprintf (stream, "%*s%-*s %d\n", indent+3, "", MIN(fwidth-3, 0),
-		     "Reference count:",
-		     h->obj[u].nrefs);
-	    fprintf (stream, "%*s%-*s %lu/%lu\n", indent+3, "",
-		     MIN(fwidth-3, 0),
-		     "Size of object body:",
-		     (unsigned long)(h->obj[u].size),
-		     (unsigned long)H5HG_ALIGN(h->obj[u].size));
-	    p = h->obj[u].begin + H5HG_SIZEOF_OBJHDR (f);
-	    for (j=0; j<h->obj[u].size; j+=16) {
-		fprintf (stream, "%*s%04d: ", indent+6, "", j);
-		for (k=0; k<16; k++) {
-		    if (8==k) fprintf (stream, " ");
-		    if (j+k<h->obj[u].size) {
-			fprintf (stream, "%02x ", p[j+k]);
-		    } else {
-			HDfputs("   ", stream);
-		    }
-		}
-		for (k=0; k<16 && j+k<h->obj[u].size; k++) {
-		    if (8==k) fprintf (stream, " ");
-		    HDfputc(p[j+k]>' ' && p[j+k]<='~' ? p[j+k] : '.', stream);
-		}
-		fprintf (stream, "\n");
-	    }
-	}
-    }
-    
-done:
     FUNC_LEAVE_NOAPI(ret_value);
 }
+
diff --git a/src/H5HGdbg.c b/src/H5HGdbg.c
index 68a3e85..a16dabb 100644
--- a/src/H5HGdbg.c
+++ b/src/H5HGdbg.c
@@ -29,6 +29,10 @@
 #include "H5HGpkg.h"		/* Global heaps				*/
 #include "H5Iprivate.h"		/* ID Functions		                */
 
+/* Interface initialization */
+static int interface_initialize_g = 0;
+#define INTERFACE_INIT NULL
+
 
 /*-------------------------------------------------------------------------
  * Function:	H5HG_debug
@@ -75,7 +79,7 @@ H5HG_debug(H5F_t *f, hid_t dxpl_id, haddr_t addr, FILE *stream, int indent,
     fprintf(stream, "%*sGlobal Heap Collection...\n", indent, "");
     fprintf(stream, "%*s%-*s %d\n", indent, "", fwidth,
 	    "Dirty:",
-	    (int)(h->cache_info.is_dirty));
+	    (int)(h->cache_info.dirty));
     fprintf(stream, "%*s%-*s %lu\n", indent, "", fwidth,
 	    "Total collection size in file:",
 	    (unsigned long)(h->size));
diff --git a/src/H5HL.c b/src/H5HL.c
index 3813efe..44976a8 100644
--- a/src/H5HL.c
+++ b/src/H5HL.c
@@ -29,6 +29,7 @@
  *-------------------------------------------------------------------------
  */
 #define H5F_PACKAGE		/* Suppress error about including H5Fpkg  */
+#define H5HL_PACKAGE		/* Suppress error about including H5HLpkg */
 
 /* Pablo information */
 /* (Put before include files to avoid problems with inline functions) */
@@ -39,19 +40,12 @@
 #include "H5Eprivate.h"		/* Error handling		  	*/
 #include "H5Fpkg.h"             /* File access				*/
 #include "H5FLprivate.h"	/* Free lists                           */
-#include "H5HLprivate.h"	/* Local Heaps				*/
+#include "H5HLpkg.h"		/* Local Heaps				*/
 #include "H5MFprivate.h"	/* File memory management		*/
-#include "H5MMprivate.h"	/* Memory management			*/
 
 /* Private macros */
 #define H5HL_FREE_NULL	1		/*end of free list on disk	*/
 #define H5HL_MIN_HEAP   256             /* Minimum size to reduce heap buffer to */
-#define H5HL_SIZEOF_HDR(F)						      \
-    H5HL_ALIGN(H5HL_SIZEOF_MAGIC +	/*heap signature		*/    \
-	       4 +			/*reserved			*/    \
-	       H5F_SIZEOF_SIZE (F) +	/*data size			*/    \
-	       H5F_SIZEOF_SIZE (F) +	/*free list head		*/    \
-	       H5F_SIZEOF_ADDR (F))	/*data address			*/
 
 /*
  * Local heap collection version.
@@ -59,23 +53,6 @@
 #define H5HL_VERSION	0
 
 /* Private typedefs */
-typedef struct H5HL_free_t {
-    size_t		offset;		/*offset of free block		*/
-    size_t		size;		/*size of free block		*/
-    struct H5HL_free_t	*prev;		/*previous entry in free list	*/
-    struct H5HL_free_t	*next;		/*next entry in free list	*/
-} H5HL_free_t;
-
-struct H5HL_t {
-    H5AC_info_t cache_info; /* Information for H5AC cache functions, _must_ be */
-                            /* first field in structure */
-    haddr_t		    addr;	/*address of data		*/
-    size_t		    disk_alloc;	/*data bytes allocated on disk	*/
-    size_t		    mem_alloc;	/*data bytes allocated in mem	*/
-    size_t                  disk_resrv; /*data bytes "reserved" on disk */
-    uint8_t		   *chunk;	/*the chunk, including header	*/
-    H5HL_free_t		   *freelist;	/*the free list			*/
-};
 
 /* PRIVATE PROTOTYPES */
 #ifdef NOT_YET
@@ -99,7 +76,7 @@ static herr_t H5HL_clear(H5HL_t *heap);
 /*
  * H5HL inherits cache-like properties from H5AC
  */
-static const H5AC_class_t H5AC_LHEAP[1] = {{
+const H5AC_class_t H5AC_LHEAP[1] = {{
     H5AC_LHEAP_ID,
     (H5AC_load_func_t)H5HL_load,
     (H5AC_flush_func_t)H5HL_flush,
@@ -737,7 +714,7 @@ H5HL_read(H5F_t *f, hid_t dxpl_id, haddr_t addr, size_t offset, size_t size, voi
     assert(f);
     assert (H5F_addr_defined(addr));
 
-    if (NULL == (heap = H5AC_protect(f, dxpl_id, H5AC_LHEAP, addr, NULL, NULL)))
+    if (NULL == (heap = H5AC_protect(f, dxpl_id, H5AC_LHEAP, addr, NULL, NULL, H5AC_READ)))
 	HGOTO_ERROR(H5E_HEAP, H5E_CANTLOAD, NULL, "unable to load heap");
 
     assert(offset < heap->mem_alloc);
@@ -803,7 +780,7 @@ H5HL_protect(H5F_t *f, hid_t dxpl_id, haddr_t addr)
     assert(f);
     assert(H5F_addr_defined(addr));
 
-    if (NULL == (ret_value = H5AC_protect(f, dxpl_id, H5AC_LHEAP, addr, NULL, NULL)))
+    if (NULL == (ret_value = H5AC_protect(f, dxpl_id, H5AC_LHEAP, addr, NULL, NULL, H5AC_READ)))
         HGOTO_ERROR(H5E_HEAP, H5E_CANTLOAD, NULL, "unable to load heap");
 
 done:
@@ -950,7 +927,7 @@ H5HL_insert(H5F_t *f, hid_t dxpl_id, haddr_t addr, size_t buf_size, const void *
     if (0==(f->intent & H5F_ACC_RDWR))
 	HGOTO_ERROR (H5E_HEAP, H5E_WRITEERROR, (size_t)(-1), "no write intent on file");
 
-    if (NULL == (heap = H5AC_protect(f, dxpl_id, H5AC_LHEAP, addr, NULL, NULL)))
+    if (NULL == (heap = H5AC_protect(f, dxpl_id, H5AC_LHEAP, addr, NULL, NULL, H5AC_WRITE)))
 	HGOTO_ERROR(H5E_HEAP, H5E_PROTECT, (size_t)(-1), "unable to load heap");
 
     heap->cache_info.dirty=TRUE;
@@ -1133,7 +1110,7 @@ H5HL_write(H5F_t *f, hid_t dxpl_id, haddr_t addr, size_t offset, size_t size, co
     if (0==(f->intent & H5F_ACC_RDWR))
 	HGOTO_ERROR (H5E_HEAP, H5E_WRITEERROR, FAIL, "no write intent on file");
 
-    if (NULL == (heap = H5AC_protect(f, dxpl_id, H5AC_LHEAP, addr, NULL, NULL)))
+    if (NULL == (heap = H5AC_protect(f, dxpl_id, H5AC_LHEAP, addr, NULL, NULL, H5AC_WRITE)))
 	HGOTO_ERROR(H5E_HEAP, H5E_PROTECT, FAIL, "unable to load heap");
 
     assert(offset < heap->mem_alloc);
@@ -1198,7 +1175,7 @@ H5HL_remove(H5F_t *f, hid_t dxpl_id, haddr_t addr, size_t offset, size_t size)
 
     size = H5HL_ALIGN (size);
 
-    if (NULL == (heap = H5AC_protect(f, dxpl_id, H5AC_LHEAP, addr, NULL, NULL)))
+    if (NULL == (heap = H5AC_protect(f, dxpl_id, H5AC_LHEAP, addr, NULL, NULL, H5AC_WRITE)))
 	HGOTO_ERROR(H5E_HEAP, H5E_PROTECT, FAIL, "unable to load heap");
 
     assert(offset < heap->mem_alloc);
@@ -1323,7 +1300,7 @@ H5HL_delete(H5F_t *f, hid_t dxpl_id, haddr_t addr)
     sizeof_hdr= H5HL_SIZEOF_HDR(f);
 
     /* Get heap pointer */
-    if (NULL == (heap = H5AC_protect(f, dxpl_id, H5AC_LHEAP, addr, NULL, NULL)))
+    if (NULL == (heap = H5AC_protect(f, dxpl_id, H5AC_LHEAP, addr, NULL, NULL, H5AC_WRITE)))
 	HGOTO_ERROR(H5E_HEAP, H5E_CANTLOAD, FAIL, "unable to load heap");
 
     /* Check if the heap is contiguous on disk */
@@ -1354,146 +1331,9 @@ H5HL_delete(H5F_t *f, hid_t dxpl_id, haddr_t addr)
     heap = NULL;
 
 done:
-    if (heap && H5AC_unprotect(f, dxpl_id, H5AC_LHEAP, addr, heap, FALSE)<0 && ret_value<0)
+    if (heap && H5AC_unprotect(f, dxpl_id, H5AC_LHEAP, addr, heap, FALSE)<0)
 	HDONE_ERROR(H5E_HEAP, H5E_PROTECT, FAIL, "unable to release local heap");
 
     FUNC_LEAVE_NOAPI(ret_value);
 } /* end H5HL_delete() */
 
-
-/*-------------------------------------------------------------------------
- * Function:	H5HL_debug
- *
- * Purpose:	Prints debugging information about a heap.
- *
- * Return:	Non-negative on success/Negative on failure
- *
- * Programmer:	Robb Matzke
- *		matzke@llnl.gov
- *		Aug  1 1997
- *
- * Modifications:
- *		Robb Matzke, 1999-07-28
- *		The ADDR argument is passed by value.
- *-------------------------------------------------------------------------
- */
-herr_t
-H5HL_debug(H5F_t *f, hid_t dxpl_id, haddr_t addr, FILE * stream, int indent, int fwidth)
-{
-    H5HL_t		*h = NULL;
-    int			i, j, overlap, free_block;
-    uint8_t		c;
-    H5HL_free_t		*freelist = NULL;
-    uint8_t		*marker = NULL;
-    size_t		amount_free = 0;
-    herr_t      ret_value=SUCCEED;       /* Return value */
-
-    FUNC_ENTER_NOAPI(H5HL_debug, FAIL);
-
-    /* check arguments */
-    assert(f);
-    assert(H5F_addr_defined(addr));
-    assert(stream);
-    assert(indent >= 0);
-    assert(fwidth >= 0);
-
-    if (NULL == (h = H5AC_find(f, dxpl_id, H5AC_LHEAP, addr, NULL, NULL)))
-	HGOTO_ERROR(H5E_HEAP, H5E_CANTLOAD, FAIL, "unable to load heap");
-    fprintf(stream, "%*sLocal Heap...\n", indent, "");
-    fprintf(stream, "%*s%-*s %d\n", indent, "", fwidth,
-	    "Dirty:",
-	    (int) (h->cache_info.dirty));
-    fprintf(stream, "%*s%-*s %lu\n", indent, "", fwidth,
-	    "Header size (in bytes):",
-	    (unsigned long) H5HL_SIZEOF_HDR(f));
-    HDfprintf(stream, "%*s%-*s %a\n", indent, "", fwidth,
-	      "Address of heap data:",
-	      h->addr);
-    HDfprintf(stream, "%*s%-*s %Zu\n", indent, "", fwidth,
-	    "Data bytes allocated on disk:",
-            h->disk_alloc);
-    HDfprintf(stream, "%*s%-*s %Zu\n", indent, "", fwidth,
-	    "Data bytes allocated in core:",
-            h->mem_alloc);
-
-    /*
-     * Traverse the free list and check that all free blocks fall within
-     * the heap and that no two free blocks point to the same region of
-     * the heap.
-     */
-    if (NULL==(marker = H5MM_calloc(h->mem_alloc)))
-	HGOTO_ERROR (H5E_RESOURCE, H5E_NOSPACE, FAIL, "memory allocation failed");
-    fprintf(stream, "%*sFree Blocks (offset, size):\n", indent, "");
-    for (free_block=0, freelist = h->freelist; freelist; freelist = freelist->next, free_block++) {
-        char temp_str[32];
-
-        sprintf(temp_str,"Block #%d:",free_block);
-	HDfprintf(stream, "%*s%-*s %8Zu, %8Zu\n", indent+3, "", MAX(0,fwidth-9),
-		temp_str,
-		freelist->offset, freelist->size);
-	if (freelist->offset + freelist->size > h->mem_alloc) {
-	    fprintf(stream, "***THAT FREE BLOCK IS OUT OF BOUNDS!\n");
-	} else {
-	    for (i=overlap=0; i<(int)(freelist->size); i++) {
-		if (marker[freelist->offset + i])
-		    overlap++;
-		marker[freelist->offset + i] = 1;
-	    }
-	    if (overlap) {
-		fprintf(stream, "***THAT FREE BLOCK OVERLAPPED A PREVIOUS "
-			"ONE!\n");
-	    } else {
-		amount_free += freelist->size;
-	    }
-	}
-    }
-
-    if (h->mem_alloc) {
-	fprintf(stream, "%*s%-*s %.2f%%\n", indent, "", fwidth,
-		"Percent of heap used:",
-		(100.0 * (double)(h->mem_alloc - amount_free) / (double)h->mem_alloc));
-    }
-    /*
-     * Print the data in a VMS-style octal dump.
-     */
-    fprintf(stream, "%*sData follows (`__' indicates free region)...\n",
-	    indent, "");
-    for (i=0; i<(int)(h->disk_alloc); i+=16) {
-	fprintf(stream, "%*s %8d: ", indent, "", i);
-	for (j = 0; j < 16; j++) {
-	    if (i+j<(int)(h->disk_alloc)) {
-		if (marker[i + j]) {
-		    fprintf(stream, "__ ");
-		} else {
-		    c = h->chunk[H5HL_SIZEOF_HDR(f) + i + j];
-		    fprintf(stream, "%02x ", c);
-		}
-	    } else {
-		fprintf(stream, "   ");
-	    }
-	    if (7 == j)
-		HDfputc(' ', stream);
-	}
-
-	for (j = 0; j < 16; j++) {
-	    if (i+j < (int)(h->disk_alloc)) {
-		if (marker[i + j]) {
-		    HDfputc(' ', stream);
-		} else {
-		    c = h->chunk[H5HL_SIZEOF_HDR(f) + i + j];
-		    if (c > ' ' && c < '~')
-			HDfputc(c, stream);
-		    else
-			HDfputc('.', stream);
-		}
-	    }
-	}
-
-	HDfputc('\n', stream);
-    }
-
-    H5MM_xfree(marker);
-
-done:
-    FUNC_LEAVE_NOAPI(ret_value);
-}
diff --git a/src/H5HLdbg.c b/src/H5HLdbg.c
index aefa7c1..ee5f360 100644
--- a/src/H5HLdbg.c
+++ b/src/H5HLdbg.c
@@ -30,6 +30,10 @@
 #include "H5Iprivate.h"		/* ID Functions		                */
 #include "H5MMprivate.h"	/* Memory management			*/
 
+/* Interface initialization */
+static int interface_initialize_g = 0;
+#define INTERFACE_INIT NULL
+
 
 /*-------------------------------------------------------------------------
  * Function:	H5HL_debug
@@ -73,7 +77,7 @@ H5HL_debug(H5F_t *f, hid_t dxpl_id, haddr_t addr, FILE * stream, int indent, int
     fprintf(stream, "%*sLocal Heap...\n", indent, "");
     fprintf(stream, "%*s%-*s %d\n", indent, "", fwidth,
 	    "Dirty:",
-	    (int) (h->cache_info.is_dirty));
+	    (int) (h->cache_info.dirty));
     fprintf(stream, "%*s%-*s %lu\n", indent, "", fwidth,
 	    "Header size (in bytes):",
 	    (unsigned long) H5HL_SIZEOF_HDR(f));
diff --git a/src/H5O.c b/src/H5O.c
index 412b302..807ed06 100644
--- a/src/H5O.c
+++ b/src/H5O.c
@@ -1175,7 +1175,7 @@ H5O_link(const H5G_entry_t *ent, int adjust, hid_t dxpl_id)
 
     /* get header */
     if (NULL == (oh = H5AC_protect(ent->file, dxpl_id, H5AC_OHDR, ent->header,
-				   NULL, NULL)))
+				   NULL, NULL, H5AC_WRITE)))
 	HGOTO_ERROR(H5E_OHDR, H5E_CANTLOAD, FAIL, "unable to load object header");
 
     /* adjust link count */
@@ -1308,7 +1308,7 @@ H5O_count_real (H5G_entry_t *ent, const H5O_class_t *type, hid_t dxpl_id)
     assert (type);
 
     /* Load the object header */
-    if (NULL == (oh = H5AC_protect(ent->file, dxpl_id, H5AC_OHDR, ent->header, NULL, NULL)))
+    if (NULL == (oh = H5AC_protect(ent->file, dxpl_id, H5AC_OHDR, ent->header, NULL, NULL, H5AC_READ)))
 	HGOTO_ERROR (H5E_OHDR, H5E_CANTLOAD, FAIL, "unable to load object header");
 
     /* Loop over all messages, counting the ones of the type looked for */
@@ -1410,7 +1410,7 @@ H5O_exists_real(H5G_entry_t *ent, const H5O_class_t *type, int sequence, hid_t d
     assert(sequence>=0);
 
     /* Load the object header */
-    if (NULL == (oh = H5AC_protect(ent->file, dxpl_id, H5AC_OHDR, ent->header, NULL, NULL)))
+    if (NULL == (oh = H5AC_protect(ent->file, dxpl_id, H5AC_OHDR, ent->header, NULL, NULL, H5AC_READ)))
 	HGOTO_ERROR(H5E_OHDR, H5E_CANTLOAD, FAIL, "unable to load object header");
 
     /* Scan through the messages looking for the right one */
@@ -1546,7 +1546,7 @@ H5O_read_real(H5G_entry_t *ent, const H5O_class_t *type, int sequence, void *mes
     }
 
     /* copy the message to the user-supplied buffer */
-    if (NULL == (oh = H5AC_protect(ent->file, dxpl_id, H5AC_OHDR, ent->header, NULL, NULL)))
+    if (NULL == (oh = H5AC_protect(ent->file, dxpl_id, H5AC_OHDR, ent->header, NULL, NULL, H5AC_READ)))
 	HGOTO_ERROR(H5E_OHDR, H5E_CANTLOAD, NULL, "unable to load object header");
 
     /* can we get it from the object header? */
@@ -1799,7 +1799,7 @@ H5O_modify_real(H5G_entry_t *ent, const H5O_class_t *type, int overwrite,
     if (0==(ent->file->intent & H5F_ACC_RDWR))
 	HGOTO_ERROR (H5E_OHDR, H5E_WRITEERROR, FAIL, "no write intent on file");
 
-    if (NULL == (oh = H5AC_protect(ent->file, dxpl_id, H5AC_OHDR, ent->header, NULL, NULL)))
+    if (NULL == (oh = H5AC_protect(ent->file, dxpl_id, H5AC_OHDR, ent->header, NULL, NULL, H5AC_WRITE)))
 	HGOTO_ERROR(H5E_OHDR, H5E_CANTLOAD, FAIL, "unable to load object header");
 
     /* Count similar messages */
@@ -1888,7 +1888,7 @@ H5O_protect(H5G_entry_t *ent, hid_t dxpl_id)
     if (0==(ent->file->intent & H5F_ACC_RDWR))
 	HGOTO_ERROR (H5E_OHDR, H5E_WRITEERROR, NULL, "no write intent on file");
 
-    if (NULL == (ret_value = H5AC_protect(ent->file, dxpl_id, H5AC_OHDR, ent->header, NULL, NULL)))
+    if (NULL == (ret_value = H5AC_protect(ent->file, dxpl_id, H5AC_OHDR, ent->header, NULL, NULL, H5AC_WRITE)))
 	HGOTO_ERROR(H5E_OHDR, H5E_CANTLOAD, NULL, "unable to load object header");
 
 done:
@@ -2261,7 +2261,7 @@ H5O_touch(H5G_entry_t *ent, hbool_t force, hid_t dxpl_id)
 	HGOTO_ERROR(H5E_OHDR, H5E_WRITEERROR, FAIL, "no write intent on file");
 
     /* Get the object header */
-    if (NULL==(oh=H5AC_protect(ent->file, dxpl_id, H5AC_OHDR, ent->header, NULL, NULL)))
+    if (NULL==(oh=H5AC_protect(ent->file, dxpl_id, H5AC_OHDR, ent->header, NULL, NULL, H5AC_WRITE)))
 	HGOTO_ERROR(H5E_OHDR, H5E_CANTLOAD, FAIL, "unable to load object header");
 
     /* Create/Update the modification time message */
@@ -2365,7 +2365,7 @@ H5O_bogus(H5G_entry_t *ent, hid_t dxpl_id)
 	HGOTO_ERROR(H5E_OHDR, H5E_WRITEERROR, FAIL, "no write intent on file");
 
     /* Get the object header */
-    if (NULL==(oh=H5AC_protect(ent->file, dxpl_id, H5AC_OHDR, ent->header, NULL, NULL)))
+    if (NULL==(oh=H5AC_protect(ent->file, dxpl_id, H5AC_OHDR, ent->header, NULL, NULL, H5AC_WRITE)))
 	HGOTO_ERROR(H5E_OHDR, H5E_CANTLOAD, FAIL, "unable to load object header");
 
     /* Create the "bogus" message */
@@ -2482,7 +2482,7 @@ H5O_remove_real(H5G_entry_t *ent, const H5O_class_t *type, int sequence, hid_t d
 	HGOTO_ERROR (H5E_HEAP, H5E_WRITEERROR, FAIL, "no write intent on file");
 
     /* load the object header */
-    if (NULL == (oh = H5AC_protect(ent->file, dxpl_id, H5AC_OHDR, ent->header, NULL, NULL)))
+    if (NULL == (oh = H5AC_protect(ent->file, dxpl_id, H5AC_OHDR, ent->header, NULL, NULL, H5AC_WRITE)))
 	HGOTO_ERROR(H5E_OHDR, H5E_CANTLOAD, FAIL, "unable to load object header");
     
     for (u = seq = 0, curr_msg=&oh->mesg[0]; u < oh->nmesgs; u++,curr_msg++) {
@@ -3171,7 +3171,7 @@ H5O_delete(H5F_t *f, hid_t dxpl_id, haddr_t addr)
     assert(H5F_addr_defined(addr));
 
     /* Get the object header information */
-    if (NULL == (oh = H5AC_protect(f, dxpl_id, H5AC_OHDR, addr, NULL, NULL)))
+    if (NULL == (oh = H5AC_protect(f, dxpl_id, H5AC_OHDR, addr, NULL, NULL, H5AC_WRITE)))
 	HGOTO_ERROR(H5E_OHDR, H5E_CANTLOAD, FAIL, "unable to load object header");
 
     /* Delete object */
@@ -3340,7 +3340,7 @@ H5O_get_info(H5G_entry_t *ent, H5O_stat_t *ostat, hid_t dxpl_id)
     assert (ostat);
 
     /* Get the object header information */
-    if (NULL == (oh = H5AC_protect(ent->file, dxpl_id, H5AC_OHDR, ent->header, NULL, NULL)))
+    if (NULL == (oh = H5AC_protect(ent->file, dxpl_id, H5AC_OHDR, ent->header, NULL, NULL, H5AC_READ)))
 	HGOTO_ERROR(H5E_OHDR, H5E_CANTLOAD, FAIL, "unable to load object header");
 
     /* Iterate over all the messages, accumulating the total size & free space */
@@ -3450,7 +3450,7 @@ H5O_debug(H5F_t *f, hid_t dxpl_id, haddr_t addr, FILE *stream, int indent, int f
     assert(indent >= 0);
     assert(fwidth >= 0);
 
-    if (NULL == (oh = H5AC_protect(f, dxpl_id, H5AC_OHDR, addr, NULL, NULL)))
+    if (NULL == (oh = H5AC_protect(f, dxpl_id, H5AC_OHDR, addr, NULL, NULL, H5AC_READ)))
 	HGOTO_ERROR(H5E_OHDR, H5E_CANTLOAD, FAIL, "unable to load object header");
 
     /* debug */
diff --git a/src/H5T.c b/src/H5T.c
index 0c9b80c..e7a8392 100644
--- a/src/H5T.c
+++ b/src/H5T.c
@@ -3415,7 +3415,6 @@ H5T_set_size(H5T_t *dt, size_t size)
                 if(size<dt->shared->size) {
                     int         num_membs;
                     unsigned    i, max_index=0;
-                    H5T_t       *memb_type;
                     size_t      memb_offset, max_offset=0;
                     size_t      max_size;
 
diff --git a/src/Makefile.in b/src/Makefile.in
index ffd8cef..8827351 100644
--- a/src/Makefile.in
+++ b/src/Makefile.in
@@ -36,7 +36,8 @@ LIB_SRC=H5.c H5A.c H5AC.c H5B.c H5D.c H5Dcontig.c H5Dcompact.c H5Defl.c       \
         H5FDcore.c H5FDfamily.c H5FDgass.c H5FDlog.c H5FDmpi.c H5FDmpio.c     \
         H5FDmpiposix.c H5FDmulti.c H5FDsec2.c H5FDsrb.c H5FDstdio.c           \
         H5FDstream.c H5FL.c H5FO.c H5FS.c H5G.c H5Gent.c H5Gnode.c H5Gstab.c  \
-        H5HG.c H5HL.c H5HP.c H5I.c H5MF.c H5MM.c H5O.c H5Oattr.c H5Obogus.c   \
+        H5HG.c H5HGdbg.c H5HL.c H5HLdbg.c H5HP.c H5I.c H5MF.c H5MM.c H5O.c    \
+        H5Oattr.c H5Obogus.c \
         H5Ocont.c H5Odtype.c H5Oefl.c H5Ofill.c H5Olayout.c H5Omtime.c        \
         H5Oname.c H5Onull.c H5Opline.c H5Osdspace.c H5Oshared.c H5Ostab.c     \
         H5P.c H5Pdcpl.c H5Pdxpl.c H5Pfapl.c H5Pfcpl.c H5Ptest.c H5R.c H5RC.c  \