[svn-r7467] Purpose:

    Code cleanup

Description:
    Patch up a few places where the metadata cache could ask for a read lock
instead of a write lock and other minor code cleanups.

Platforms tested:
    FreeBSD 4.9 (sleipnir)
    too minor to need h5committest

Misc. update:

7 files changed, 96 insertions, 121 deletions

diff --git a/src/H5B.c b/src/H5B.c
index 5977e00..23a0607 100644
--- a/src/H5B.c
+++ b/src/H5B.c
@@ -619,6 +619,9 @@ H5B_find(H5F_t *f, hid_t dxpl_id, const H5B_class_t *type, haddr_t addr, void *u
     H5B_t	*bt = NULL;
     unsigned    idx=0, lt = 0, rt;        /* Final, left & right key indices */
     int	        cmp = 1;                /* Key comparison value */
+    int         level;                  /* Level of B-tree node */
+    haddr_t     child;                  /* Address of child to recurse to */
+    void       *nkey1, *nkey2;          /* Native keys of child */
     int		ret_value = SUCCEED;    /* Return value */
 
     FUNC_ENTER_NOAPI(H5B_find, FAIL)
@@ -637,7 +640,7 @@ 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, H5AC_WRITE)))
+    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")
     rt = bt->nchildren;
 
@@ -660,16 +663,28 @@ H5B_find(H5F_t *f, hid_t dxpl_id, const H5B_class_t *type, haddr_t addr, void *u
      * Follow the link to the subtree or to the data node.
      */
     assert(idx < bt->nchildren);
-    if (bt->level > 0) {
-	if (H5B_find(f, dxpl_id, type, bt->child[idx], udata) < 0)
+
+    /* Retrieve the rest of the B-tree information, so we can unlock it before recursing */
+    level = bt->level;
+    child = bt->child[idx];
+    nkey1=bt->key[idx].nkey;
+    nkey2=bt->key[idx+1].nkey;
+
+    if (H5AC_unprotect(f, dxpl_id, H5AC_BT, addr, bt, FALSE) < 0)
+        HGOTO_ERROR(H5E_BTREE, H5E_PROTECT, FAIL, "unable to release B-tree node")
+
+    bt = NULL;  /* Make certain future references will be caught */
+
+    if (level > 0) {
+	if (H5B_find(f, dxpl_id, type, child, udata) < 0)
 	    HGOTO_ERROR(H5E_BTREE, H5E_NOTFOUND, FAIL, "key not found in subtree")
     } else {
-	if ((type->found) (f, dxpl_id, bt->child[idx], bt->key[idx].nkey, udata, bt->key[idx+1].nkey) < 0)
+	if ((type->found) (f, dxpl_id, child, nkey1, udata, nkey2) < 0)
 	    HGOTO_ERROR(H5E_BTREE, H5E_NOTFOUND, FAIL, "key not found in leaf node")
     }
 
 done:
-    if (bt && H5AC_unprotect(f, dxpl_id, H5AC_BT, addr, bt, FALSE) < 0 && ret_value>=0)
+    if (bt && H5AC_unprotect(f, dxpl_id, H5AC_BT, addr, bt, FALSE) < 0)
 	HDONE_ERROR(H5E_BTREE, H5E_PROTECT, FAIL, "unable to release node")
 
     FUNC_LEAVE_NOAPI(ret_value)
@@ -835,7 +850,7 @@ H5B_split(H5F_t *f, hid_t dxpl_id, const H5B_class_t *type, H5B_t *old_bt, haddr
     old_bt->right = *new_addr_p;
 
 done:
-    if (new_bt && H5AC_unprotect(f, dxpl_id, H5AC_BT, *new_addr_p, new_bt, FALSE) < 0 && ret_value>=0)
+    if (new_bt && H5AC_unprotect(f, dxpl_id, H5AC_BT, *new_addr_p, new_bt, FALSE) < 0)
         HDONE_ERROR(H5E_BTREE, H5E_PROTECT, FAIL, "unable to release B-tree node")
 
     FUNC_LEAVE_NOAPI(ret_value)
@@ -1269,7 +1284,7 @@ H5B_insert_helper(H5F_t *f, hid_t dxpl_id, haddr_t addr, const H5B_class_t *type
 		  uint8_t *rt_key, hbool_t *rt_key_changed,
 		  haddr_t *new_node_p/*out*/)
 {
-    H5B_t	*bt = NULL, *twin = NULL, *tmp_bt = NULL;
+    H5B_t	*bt = NULL, *twin = NULL;
     unsigned	lt = 0, idx = 0, rt;    /* Left, final & right index values */
     int         cmp = -1;               /* Key comparison value */
     haddr_t	child_addr = HADDR_UNDEF;
@@ -1487,6 +1502,8 @@ H5B_insert_helper(H5F_t *f, hid_t dxpl_id, haddr_t addr, const H5B_class_t *type
 	ret_value = H5B_INS_NOOP;
 
     } else if (H5B_INS_LEFT == my_ins || H5B_INS_RIGHT == my_ins) {
+        H5B_t	*tmp_bt;
+
 	/*
 	 * If this node is full then split it before inserting the new child.
 	 */
@@ -1948,7 +1965,7 @@ H5B_remove_helper(H5F_t *f, hid_t dxpl_id, haddr_t addr, const H5B_class_t *type
     }
 
 done:
-    if (bt && H5AC_unprotect(f, dxpl_id, H5AC_BT, addr, bt, FALSE)<0 && ret_value>=0)
+    if (bt && H5AC_unprotect(f, dxpl_id, H5AC_BT, addr, bt, FALSE)<0)
 	HDONE_ERROR(H5E_BTREE, H5E_PROTECT, H5B_INS_ERROR, "unable to release node")
 
     FUNC_LEAVE_NOAPI(ret_value)
@@ -2091,14 +2108,9 @@ H5B_delete(H5F_t *f, hid_t dxpl_id, const H5B_class_t *type, haddr_t addr, void
     if (H5MF_xfree(f, H5FD_MEM_BTREE, dxpl_id, addr, sizeof_node)<0)
         HGOTO_ERROR(H5E_BTREE, H5E_CANTFREE, FAIL, "unable to free B-tree node")
     
-    /* Release node in metadata cache */
-    if (H5AC_unprotect(f, dxpl_id, H5AC_BT, addr, bt, TRUE)<0)
-        HGOTO_ERROR(H5E_BTREE, H5E_PROTECT, FAIL, "unable to release B-tree node in cache")
-    bt=NULL;    /* Make certain future references will be caught */
-
 done:
-    if (bt && H5AC_unprotect(f, dxpl_id, H5AC_BT, addr, bt, FALSE)<0)
-        HGOTO_ERROR(H5E_BTREE, H5E_PROTECT, FAIL, "unable to release B-tree node in cache")
+    if (bt && H5AC_unprotect(f, dxpl_id, H5AC_BT, addr, bt, TRUE)<0)
+        HDONE_ERROR(H5E_BTREE, H5E_PROTECT, FAIL, "unable to release B-tree node in cache")
 
     FUNC_LEAVE_NOAPI(ret_value)
 } /* end H5B_delete() */
diff --git a/src/H5Gnode.c b/src/H5Gnode.c
index 36e876b..b5ac425 100644
--- a/src/H5Gnode.c
+++ b/src/H5Gnode.c
@@ -820,7 +820,7 @@ 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, H5AC_WRITE)))
+    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 */
@@ -847,15 +847,15 @@ H5G_node_found(H5F_t *f, hid_t dxpl_id, haddr_t addr, const void UNUSED *_lt_key
 
     if (bt_udata->operation==H5G_OPER_FIND)
         /*
-         * The caller is querying the symbol entry.  Return just a pointer to
-         * the entry.  The pointer is valid until the next call to H5AC.
+         * The caller is querying the symbol entry, copy it into the UDATA
+         * entry field. (Hmm... should this use H5G_ent_copy()? - QAK)
          */
         bt_udata->ent = sn->entry[idx];
     else
         HGOTO_ERROR(H5E_SYM, H5E_UNSUPPORTED, FAIL, "internal erorr (unknown symbol find operation)");
 
 done:
-    if (sn && H5AC_unprotect(f, dxpl_id, H5AC_SNODE, addr, sn, FALSE) < 0 && ret_value>=0)
+    if (sn && H5AC_unprotect(f, dxpl_id, H5AC_SNODE, addr, sn, FALSE) < 0)
 	HDONE_ERROR(H5E_SYM, H5E_PROTECT, FAIL, "unable to release symbol table node");
 
     FUNC_LEAVE_NOAPI(ret_value);
@@ -1035,7 +1035,7 @@ H5G_node_insert(H5F_t *f, hid_t dxpl_id, haddr_t addr, void UNUSED *_lt_key,
     insert_into->nsyms += 1;
 
 done:
-    if (sn && H5AC_unprotect(f, dxpl_id, H5AC_SNODE, addr, sn, FALSE) < 0 && ret_value!=H5B_INS_ERROR)
+    if (sn && H5AC_unprotect(f, dxpl_id, H5AC_SNODE, addr, sn, FALSE) < 0)
 	HDONE_ERROR(H5E_SYM, H5E_PROTECT, H5B_INS_ERROR, "unable to release symbol table node");
 
     FUNC_LEAVE_NOAPI(ret_value);
@@ -1235,7 +1235,7 @@ H5G_node_remove(H5F_t *f, hid_t dxpl_id, haddr_t addr, void *_lt_key/*in,out*/,
     } /* end else */
     
 done:
-    if (sn && H5AC_unprotect(f, dxpl_id, H5AC_SNODE, addr, sn, FALSE)<0 && ret_value!=H5B_INS_ERROR)
+    if (sn && H5AC_unprotect(f, dxpl_id, H5AC_SNODE, addr, sn, FALSE)<0)
 	HDONE_ERROR(H5E_SYM, H5E_PROTECT, H5B_INS_ERROR, "unable to release symbol table node");
 
     FUNC_LEAVE_NOAPI(ret_value);
@@ -1333,8 +1333,8 @@ H5G_node_iterate (H5F_t *f, hid_t dxpl_id, void UNUSED *_lt_key, haddr_t addr,
 done:
     if (sn && H5AC_unprotect(f, dxpl_id, H5AC_SNODE, addr, sn, FALSE) != SUCCEED)
         HDONE_ERROR(H5E_SYM, H5E_PROTECT, H5B_ITER_ERROR, "unable to release object header");
-
     name_off = H5MM_xfree (name_off);
+
     FUNC_LEAVE_NOAPI(ret_value);
 }
 
@@ -1377,12 +1377,10 @@ H5G_node_sumup(H5F_t *f, hid_t dxpl_id, void UNUSED *_lt_key, haddr_t addr,
 
     *num_objs += sn->nsyms;
 
-    if (H5AC_unprotect(f, dxpl_id, H5AC_SNODE, addr, sn, FALSE) != SUCCEED)
-        HGOTO_ERROR(H5E_SYM, H5E_PROTECT, H5B_ITER_ERROR, "unable to release object header");
-
-    sn=NULL;    /* Make certain future references will be caught */
-    
 done:
+    if (sn && H5AC_unprotect(f, dxpl_id, H5AC_SNODE, addr, sn, FALSE) != SUCCEED)
+        HDONE_ERROR(H5E_SYM, H5E_PROTECT, H5B_ITER_ERROR, "unable to release object header");
+
     FUNC_LEAVE_NOAPI(ret_value);
 }
 
@@ -1438,12 +1436,10 @@ H5G_node_name(H5F_t *f, hid_t dxpl_id, void UNUSED *_lt_key, haddr_t addr,
         bt_udata->num_objs += sn->nsyms;
     }
 
-    if (H5AC_unprotect(f, dxpl_id, H5AC_SNODE, addr, sn, FALSE) != SUCCEED)
-        HGOTO_ERROR(H5E_SYM, H5E_PROTECT, H5B_ITER_ERROR, "unable to release object header");
-
-    sn=NULL;    /* Make certain future references will be caught */
-    
 done:
+    if (sn && H5AC_unprotect(f, dxpl_id, H5AC_SNODE, addr, sn, FALSE) != SUCCEED)
+        HDONE_ERROR(H5E_SYM, H5E_PROTECT, H5B_ITER_ERROR, "unable to release object header");
+
     FUNC_LEAVE_NOAPI(ret_value);
 }
 
@@ -1491,12 +1487,10 @@ H5G_node_type(H5F_t *f, hid_t dxpl_id, void UNUSED *_lt_key, haddr_t addr,
         bt_udata->num_objs += sn->nsyms;
     }
 
-    if (H5AC_unprotect(f, dxpl_id, H5AC_SNODE, addr, sn, FALSE) != SUCCEED)
-        HGOTO_ERROR(H5E_SYM, H5E_PROTECT, H5B_ITER_ERROR, "unable to release object header");
-
-    sn=NULL;    /* Make certain future references will be caught */
-    
 done:
+    if (sn && H5AC_unprotect(f, dxpl_id, H5AC_SNODE, addr, sn, FALSE) != SUCCEED)
+        HDONE_ERROR(H5E_SYM, H5E_PROTECT, H5B_ITER_ERROR, "unable to release object header");
+    
     FUNC_LEAVE_NOAPI(ret_value);
 }
 
@@ -1574,9 +1568,6 @@ H5G_node_debug(H5F_t *f, hid_t dxpl_id, haddr_t addr, FILE * stream, int indent,
 	H5G_ent_debug(f, dxpl_id, sn->entry + i, stream, indent, fwidth, heap);
     }
 
-    H5AC_unprotect(f, dxpl_id, H5AC_SNODE, addr, sn, FALSE);
-    sn = NULL;
-
 done:
     if (sn && H5AC_unprotect(f, dxpl_id, H5AC_SNODE, addr, sn, FALSE) < 0)
 	HDONE_ERROR(H5E_SYM, H5E_PROTECT, FAIL, "unable to release symbol table node");
diff --git a/src/H5HG.c b/src/H5HG.c
index 096c075..98372eb 100644
--- a/src/H5HG.c
+++ b/src/H5HG.c
@@ -788,12 +788,10 @@ H5HG_peek (H5F_t *f, hid_t dxpl_id, H5HG_t *hobj)
 	}
     }
 
-    if (H5AC_unprotect(f, dxpl_id, H5AC_GHEAP, hobj->addr, heap, FALSE) != SUCCEED)
-        HGOTO_ERROR(H5E_HEAP, H5E_PROTECT, FAIL, "unable to release object header");
-
-    heap=NULL;
-    
 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);
 }
 #endif /* NOT_YET */
@@ -861,18 +859,11 @@ H5HG_read (H5F_t *f, hid_t dxpl_id, H5HG_t *hobj, void *object/*out*/)
 	}
     }
 
-    if (H5AC_unprotect(f, dxpl_id, H5AC_GHEAP, hobj->addr, heap, FALSE) != SUCCEED) {
-        heap = NULL;
-        HGOTO_ERROR(H5E_HEAP, H5E_PROTECT, NULL, "unable to release object header");
-    }
-
-    heap = NULL;
-
     /* Set return value */
     ret_value=object;
 
 done:
-    if (heap && H5AC_unprotect(f, dxpl_id, H5AC_GHEAP, hobj->addr, heap, FALSE) != SUCCEED)
+    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);
@@ -913,25 +904,26 @@ H5HG_link (H5F_t *f, hid_t dxpl_id, 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_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->nalloc);
-    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->nalloc);
+        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) != SUCCEED && ret_value != FAIL)
+    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);
diff --git a/src/H5HGdbg.c b/src/H5HGdbg.c
index 4e7b8a8..64f0ea4 100644
--- a/src/H5HGdbg.c
+++ b/src/H5HGdbg.c
@@ -131,11 +131,9 @@ H5HG_debug(H5F_t *f, hid_t dxpl_id, haddr_t addr, FILE *stream, int indent,
 	}
     }
 
-    if (H5AC_unprotect(f, dxpl_id, H5AC_GHEAP, addr, h, FALSE) != SUCCEED)
-        HGOTO_ERROR(H5E_HEAP, H5E_PROTECT, FAIL, "unable to release object header");
-
-    h = NULL;
-
 done:
+    if (h && H5AC_unprotect(f, dxpl_id, H5AC_GHEAP, addr, h, FALSE) != SUCCEED)
+        HDONE_ERROR(H5E_HEAP, H5E_PROTECT, FAIL, "unable to release object header");
+
     FUNC_LEAVE_NOAPI(ret_value);
 }
diff --git a/src/H5HL.c b/src/H5HL.c
index ea08e47..3272d2d 100644
--- a/src/H5HL.c
+++ b/src/H5HL.c
@@ -639,15 +639,13 @@ H5HL_read(H5F_t *f, hid_t dxpl_id, haddr_t addr, size_t offset, size_t size, voi
 	HGOTO_ERROR (H5E_RESOURCE, H5E_NOSPACE, NULL, "memory allocation failed");
     HDmemcpy(buf, heap->chunk + H5HL_SIZEOF_HDR(f) + offset, size);
 
-    if (H5AC_unprotect(f, dxpl_id, H5AC_LHEAP, addr, heap, FALSE) != SUCCEED)
-        HGOTO_ERROR(H5E_HEAP, H5E_PROTECT, NULL, "unable to release object header");
-
-    heap=NULL;
-
     /* Set return value */
     ret_value=buf;
 
 done:
+    if (heap && H5AC_unprotect(f, dxpl_id, H5AC_LHEAP, addr, heap, FALSE) != SUCCEED)
+        HDONE_ERROR(H5E_HEAP, H5E_PROTECT, NULL, "unable to release object header");
+
     FUNC_LEAVE_NOAPI(ret_value);
 }
 #endif /* NOT_YET */
@@ -704,12 +702,10 @@ H5HL_peek(H5F_t *f, hid_t dxpl_id, haddr_t addr, size_t offset)
     /* Set return value */
     ret_value = heap->chunk + H5HL_SIZEOF_HDR(f) + offset;
 
-    if (H5AC_unprotect(f, dxpl_id, H5AC_LHEAP, addr, heap, FALSE) != SUCCEED)
-        HGOTO_ERROR(H5E_HEAP, H5E_PROTECT, NULL, "unable to release object header");
-
-    heap=NULL;
-
 done:
+    if (heap && H5AC_unprotect(f, dxpl_id, H5AC_LHEAP, addr, heap, FALSE) != SUCCEED)
+        HDONE_ERROR(H5E_HEAP, H5E_PROTECT, NULL, "unable to release object header");
+
     FUNC_LEAVE_NOAPI(ret_value);
 }
 
@@ -907,7 +903,7 @@ H5HL_insert(H5F_t *f, hid_t dxpl_id, haddr_t addr, size_t buf_size, const void *
     ret_value=offset;
 
 done:
-    if (heap && H5AC_unprotect(f, dxpl_id, H5AC_LHEAP, addr, heap, FALSE) != SUCCEED && ret_value != (size_t)(-1))
+    if (heap && H5AC_unprotect(f, dxpl_id, H5AC_LHEAP, addr, heap, FALSE) != SUCCEED)
         HDONE_ERROR(H5E_HEAP, H5E_PROTECT, (size_t)(-1), "unable to release object header");
 
     FUNC_LEAVE_NOAPI(ret_value);
@@ -1101,7 +1097,7 @@ H5HL_remove(H5F_t *f, hid_t dxpl_id, haddr_t addr, size_t offset, size_t size)
     heap->freelist = fl;
 
 done:
-    if (heap && H5AC_unprotect(f, dxpl_id, H5AC_LHEAP, addr, heap, FALSE) != SUCCEED && ret_value != FAIL)
+    if (heap && H5AC_unprotect(f, dxpl_id, H5AC_LHEAP, addr, heap, FALSE) != SUCCEED)
         HDONE_ERROR(H5E_HEAP, H5E_PROTECT, FAIL, "unable to release object header");
 
     FUNC_LEAVE_NOAPI(ret_value);
@@ -1167,15 +1163,8 @@ H5HL_delete(H5F_t *f, hid_t dxpl_id, haddr_t addr)
             HGOTO_ERROR(H5E_HEAP, H5E_CANTFREE, FAIL, "unable to free local heap data");
     } /* end else */
 
-    /* Release the local heap metadata from the cache */
-    if (H5AC_unprotect(f, dxpl_id, H5AC_LHEAP, addr, heap, TRUE)<0) {
-        heap = NULL;
-        HGOTO_ERROR(H5E_HEAP, H5E_PROTECT, FAIL, "unable to release local heap");
-    }
-    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, TRUE)<0)
 	HDONE_ERROR(H5E_HEAP, H5E_PROTECT, FAIL, "unable to release local heap");
 
     FUNC_LEAVE_NOAPI(ret_value);
diff --git a/src/H5HLdbg.c b/src/H5HLdbg.c
index adc98fc..3f330a5 100644
--- a/src/H5HLdbg.c
+++ b/src/H5HLdbg.c
@@ -168,14 +168,11 @@ H5HL_debug(H5F_t *f, hid_t dxpl_id, haddr_t addr, FILE * stream, int indent, int
 	HDfputc('\n', stream);
     }
 
-    if (H5AC_unprotect(f, dxpl_id, H5AC_LHEAP, addr, h, FALSE) != SUCCEED)
-	HGOTO_ERROR(H5E_OHDR, H5E_PROTECT, FAIL, "unable to release object header");
-
-    h = NULL;
-
+done:
+    if (h && H5AC_unprotect(f, dxpl_id, H5AC_LHEAP, addr, h, FALSE) != SUCCEED)
+	HDONE_ERROR(H5E_OHDR, H5E_PROTECT, FAIL, "unable to release object header");
     H5MM_xfree(marker);
 
-done:
     FUNC_LEAVE_NOAPI(ret_value);
 }
 
diff --git a/src/H5O.c b/src/H5O.c
index 048386d..1b237d2 100644
--- a/src/H5O.c
+++ b/src/H5O.c
@@ -1245,7 +1245,7 @@ H5O_link(H5G_entry_t *ent, int adjust, hid_t dxpl_id)
     ret_value = oh->nlink;
 
 done:
-    if (oh && H5AC_unprotect(ent->file, dxpl_id, H5AC_OHDR, ent->header, oh, deleted) < 0 && ret_value>=0)
+    if (oh && H5AC_unprotect(ent->file, dxpl_id, H5AC_OHDR, ent->header, oh, deleted) < 0)
 	HDONE_ERROR(H5E_OHDR, H5E_PROTECT, FAIL, "unable to release object header");
 
     FUNC_LEAVE_NOAPI(ret_value);
@@ -1335,20 +1335,18 @@ H5O_count_real (H5G_entry_t *ent, const H5O_class_t *type, hid_t dxpl_id)
     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");
 
-    for (u=acc=0; u<oh->nmesgs; u++) {
+    /* Loop over all messages, counting the ones of the type looked for */
+    for (u=acc=0; u<oh->nmesgs; u++)
 	if (oh->mesg[u].type==type)
             acc++;
-    }
-
-    if (H5AC_unprotect(ent->file, dxpl_id, H5AC_OHDR, ent->header, oh, FALSE) != SUCCEED)
-	HGOTO_ERROR(H5E_OHDR, H5E_PROTECT, FAIL, "unable to release object header");
-
-    oh=NULL;
 
     /* Set return value */
     ret_value=acc;
 
 done:
+    if (oh && H5AC_unprotect(ent->file, dxpl_id, H5AC_OHDR, ent->header, oh, FALSE) != SUCCEED)
+	HDONE_ERROR(H5E_OHDR, H5E_PROTECT, FAIL, "unable to release object header");
+
     FUNC_LEAVE_NOAPI(ret_value);
 } /* end H5O_count_real() */
 
@@ -1447,15 +1445,13 @@ H5O_exists_real(H5G_entry_t *ent, const H5O_class_t *type, int sequence, hid_t d
             break;
     }
 
-    if (H5AC_unprotect(ent->file, dxpl_id, H5AC_OHDR, ent->header, oh, FALSE) != SUCCEED)
-	HGOTO_ERROR(H5E_OHDR, H5E_PROTECT, FAIL, "unable to release object header");
-
-    oh=NULL;
-
     /* Set return value */
     ret_value=(sequence<0);
 
 done:
+    if (oh && H5AC_unprotect(ent->file, dxpl_id, H5AC_OHDR, ent->header, oh, FALSE) != SUCCEED)
+	HDONE_ERROR(H5E_OHDR, H5E_PROTECT, FAIL, "unable to release object header");
+
     FUNC_LEAVE_NOAPI(ret_value);
 } /* end H5O_exists_real() */
 
@@ -1572,7 +1568,7 @@ H5O_read_real(H5G_entry_t *ent, const H5O_class_t *type, int sequence, void *mes
 	HGOTO_ERROR(H5E_OHDR, H5E_NOTFOUND, NULL, "unable to find message in object header");
 
     /* copy the message to the user-supplied buffer */
-    if (NULL == (oh = H5AC_protect(ent->file, dxpl_id, H5AC_OHDR, ent->header, NULL, NULL, H5AC_WRITE)))
+    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");
     if (oh->mesg[idx].flags & H5O_FLAG_SHARED) {
 	/*
@@ -1615,7 +1611,7 @@ H5O_read_real(H5G_entry_t *ent, const H5O_class_t *type, int sequence, void *mes
     }
 
 done:
-    if (oh && H5AC_unprotect(ent->file, dxpl_id, H5AC_OHDR, ent->header, oh, FALSE) < 0 && ret_value!=NULL)
+    if (oh && H5AC_unprotect(ent->file, dxpl_id, H5AC_OHDR, ent->header, oh, FALSE) < 0)
 	HDONE_ERROR(H5E_OHDR, H5E_PROTECT, NULL, "unable to release object header");
 
     FUNC_LEAVE_NOAPI(ret_value);
@@ -1658,7 +1654,7 @@ H5O_find_in_ohdr(H5F_t *f, hid_t dxpl_id, haddr_t addr, const H5O_class_t **type
     assert(type_p);
 
     /* Load the object header */
-    if (NULL == (oh = H5AC_protect(f, dxpl_id, H5AC_OHDR, addr, NULL, NULL, H5AC_WRITE)))
+    if (NULL == (oh = H5AC_protect(f, dxpl_id, H5AC_OHDR, addr, NULL, NULL, H5AC_READ)))
 	HGOTO_ERROR(H5E_OHDR, H5E_CANTLOAD, UFAIL, "unable to load object header");
 
     /* Scan through the messages looking for the right one */
@@ -1697,7 +1693,7 @@ H5O_find_in_ohdr(H5F_t *f, hid_t dxpl_id, haddr_t addr, const H5O_class_t **type
     ret_value=u;
 
 done:
-    if (oh && H5AC_unprotect(f, dxpl_id, H5AC_OHDR, addr, oh, FALSE) != SUCCEED && ret_value != UFAIL)
+    if (oh && H5AC_unprotect(f, dxpl_id, H5AC_OHDR, addr, oh, FALSE) != SUCCEED)
         HDONE_ERROR(H5E_OHDR, H5E_PROTECT, UFAIL, "unable to release object header");
 
     FUNC_LEAVE_NOAPI(ret_value);
@@ -1947,7 +1943,7 @@ H5O_modify_real(H5G_entry_t *ent, const H5O_class_t *type, int overwrite,
     ret_value = sequence;
 
 done:
-    if (oh && H5AC_unprotect(ent->file, dxpl_id, H5AC_OHDR, ent->header, oh, FALSE) < 0 && ret_value!=FAIL)
+    if (oh && H5AC_unprotect(ent->file, dxpl_id, H5AC_OHDR, ent->header, oh, FALSE) < 0)
 	HDONE_ERROR(H5E_OHDR, H5E_PROTECT, FAIL, "unable to release object header");
     
     FUNC_LEAVE_NOAPI(ret_value);
@@ -2030,7 +2026,7 @@ H5O_unprotect(H5G_entry_t *ent, H5O_t *oh, hid_t dxpl_id)
     assert(oh);
 
     if (H5AC_unprotect(ent->file, dxpl_id, H5AC_OHDR, ent->header, oh, FALSE) < 0)
-	HDONE_ERROR(H5E_OHDR, H5E_PROTECT, FAIL, "unable to release object header");
+	HGOTO_ERROR(H5E_OHDR, H5E_PROTECT, FAIL, "unable to release object header");
 
     oh = NULL;
 
@@ -2321,7 +2317,7 @@ H5O_touch(H5G_entry_t *ent, hbool_t force, hid_t dxpl_id)
 	HGOTO_ERROR(H5E_OHDR, H5E_CANTINIT, FAIL, "unable to update object modificaton time");
 
 done:
-    if (oh && H5AC_unprotect(ent->file, dxpl_id, H5AC_OHDR, ent->header, oh, FALSE)<0 && ret_value>=0)
+    if (oh && H5AC_unprotect(ent->file, dxpl_id, H5AC_OHDR, ent->header, oh, FALSE)<0)
 	HDONE_ERROR(H5E_OHDR, H5E_PROTECT, FAIL, "unable to release object header");
 
     FUNC_LEAVE_NOAPI(ret_value);
@@ -2581,7 +2577,7 @@ H5O_remove_real(H5G_entry_t *ent, const H5O_class_t *type, int sequence, hid_t d
 	HGOTO_ERROR(H5E_OHDR, H5E_CANTINIT, FAIL, "unable to remove constant message(s)");
 
 done:
-    if (oh && H5AC_unprotect(ent->file, dxpl_id, H5AC_OHDR, ent->header, oh, FALSE) < 0 && ret_value>=0)
+    if (oh && H5AC_unprotect(ent->file, dxpl_id, H5AC_OHDR, ent->header, oh, FALSE) < 0)
 	HDONE_ERROR(H5E_OHDR, H5E_PROTECT, FAIL, "unable to release object header");
 
     FUNC_LEAVE_NOAPI(ret_value);
@@ -3171,7 +3167,7 @@ H5O_delete(H5F_t *f, hid_t dxpl_id, haddr_t addr)
         HGOTO_ERROR(H5E_OHDR, H5E_CANTDELETE, FAIL, "can't delete object from file");
 
 done:
-    if (oh && H5AC_unprotect(f, dxpl_id, H5AC_OHDR, addr, oh, TRUE)<0 && ret_value>=0)
+    if (oh && H5AC_unprotect(f, dxpl_id, H5AC_OHDR, addr, oh, TRUE)<0)
 	HDONE_ERROR(H5E_OHDR, H5E_PROTECT, FAIL, "unable to release object header");
 
     FUNC_LEAVE_NOAPI(ret_value);
@@ -3345,7 +3341,7 @@ 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, H5AC_WRITE)))
+    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 */
@@ -3485,7 +3481,7 @@ H5O_debug(H5F_t *f, hid_t dxpl_id, haddr_t addr, FILE *stream, int indent, int f
 	HDfprintf(stream, "*** TOTAL SIZE DOES NOT MATCH ALLOCATED SIZE!\n");
 
 done:
-    if (oh && H5AC_unprotect(f, dxpl_id, H5AC_OHDR, addr, oh, FALSE) < 0 && ret_value>=0)
+    if (oh && H5AC_unprotect(f, dxpl_id, H5AC_OHDR, addr, oh, FALSE) < 0)
 	HDONE_ERROR(H5E_OHDR, H5E_PROTECT, FAIL, "unable to release object header");
 
     FUNC_LEAVE_NOAPI(ret_value);