[svn-r17785] Description:

	Further refactor v2 B-tree code to bring it closer to modern data
structure designed in the library, mainly by introducing a H5B2_t type so that
the v2 B-tree could be held open, but not require the B-tree header to be
protected the whole time.  A few other minor tweaks as well.

	Also, remove unused 'dirty' flag from fractal heap header.

Tested on:
        FreeBSD/32 6.3 (duty) in debug mode
        FreeBSD/64 6.3 (liberty) w/C++ & FORTRAN, in debug mode
        Linux/32 2.6 (jam) w/PGI compilers, w/default API=1.8.x,
                w/C++ & FORTRAN, w/threadsafe, in debug mode
        Linux/64-amd64 2.6 (smirom) w/Intel compilers, w/default API=1.6.x,
                w/C++ & FORTRAN, in production mode
        Solaris/32 2.10 (linew) w/deprecated symbols disabled, w/C++ & FORTRAN,
                w/szip filter, in production mode
        Linux/64-ia64 2.6 (cobalt) w/Intel compilers, w/C++ & FORTRAN,
                in production mode
        Linux/64-ia64 2.4 (tg-login3) w/parallel, w/FORTRAN, in debug mode
        Linux/64-amd64 2.6 (abe) w/parallel, w/FORTRAN, in production mode
        Mac OS X/32 10.6.1 (amazon) in debug mode
        Mac OS X/32 10.6.1 (amazon) w/C++ & FORTRAN, w/threadsafe,
                in production mode

11 files changed, 431 insertions, 186 deletions

diff --git a/src/H5B2.c b/src/H5B2.c
index 6408dc4..a30a6e2 100644
--- a/src/H5B2.c
+++ b/src/H5B2.c
@@ -61,9 +61,9 @@
 /********************/
 /* Local Prototypes */
 /********************/
-static H5B2_hdr_t *H5B2_open(H5F_t *f, hid_t dxpl_id, const H5B2_class_t *type,
-    haddr_t addr, H5AC_protect_t rw);
-static herr_t H5B2_close(H5B2_hdr_t *hdr, hid_t dxpl_id);
+static H5B2_t *H5B2_open(H5F_t *f, hid_t dxpl_id, const H5B2_class_t *cls,
+    haddr_t addr);
+static herr_t H5B2_close(H5B2_t *bt2, hid_t dxpl_id);
 
 
 /*********************/
@@ -80,6 +80,10 @@ static herr_t H5B2_close(H5B2_hdr_t *hdr, hid_t dxpl_id);
 /* Local Variables */
 /*******************/
 
+/* Declare a free list to manage the H5B2_t struct */
+H5FL_DEFINE_STATIC(H5B2_t);
+
+
 
 /*-------------------------------------------------------------------------
  * Function:	H5B2_create
@@ -137,34 +141,53 @@ done:
  *
  *-------------------------------------------------------------------------
  */
-static H5B2_hdr_t *
-H5B2_open(H5F_t *f, hid_t dxpl_id, const H5B2_class_t *type, haddr_t addr,
-    H5AC_protect_t rw)
+static H5B2_t *
+H5B2_open(H5F_t *f, hid_t dxpl_id, const H5B2_class_t *cls, haddr_t addr)
 {
+    H5B2_t	*bt2 = NULL;            /* Pointer to the B-tree */
     H5B2_hdr_t	*hdr = NULL;            /* Pointer to the B-tree header */
-    H5B2_hdr_t	*ret_value;             /* Return value */
+    H5B2_t	*ret_value;             /* Return value */
 
     FUNC_ENTER_NOAPI_NOINIT(H5B2_open)
 
     /* Check arguments. */
     HDassert(f);
-    HDassert(type);
+    HDassert(cls);
     HDassert(H5F_addr_defined(addr));
 
     /* Look up the B-tree header */
-    if(NULL == (hdr = (H5B2_hdr_t *)H5AC_protect(f, dxpl_id, H5AC_BT2_HDR, addr, type, NULL, rw)))
+    if(NULL == (hdr = (H5B2_hdr_t *)H5AC_protect(f, dxpl_id, H5AC_BT2_HDR, addr, cls, NULL, H5AC_READ)))
 	HGOTO_ERROR(H5E_BTREE, H5E_CANTPROTECT, NULL, "unable to load B-tree header")
 
-    /* Set file pointer for this B-tree operation */
-    hdr->f = f;
+    /* Check for pending heap deletion */
+    if(hdr->pending_delete)
+        HGOTO_ERROR(H5E_BTREE, H5E_CANTOPENOBJ, NULL, "can't open v2 B-tree pending deletion")
+
+    /* Create v2 B-tree info */
+    if(NULL == (bt2 = H5FL_MALLOC(H5B2_t)))
+        HGOTO_ERROR(H5E_BTREE, H5E_CANTALLOC, NULL, "memory allocation failed for v2 B-tree info")
+
+    /* Point v2 B-tree wrapper at header */
+    bt2->hdr = hdr;
+    if(H5B2_hdr_incr(bt2->hdr) < 0)
+        HGOTO_ERROR(H5E_BTREE, H5E_CANTINC, NULL, "can't increment reference count on shared v2 B-tree header")
+
+    /* Increment # of files using this v2 B-tree header */
+    if(H5B2_hdr_fuse_incr(bt2->hdr) < 0)
+	HGOTO_ERROR(H5E_BTREE, H5E_CANTINC, NULL, "can't increment file reference count on shared v2 B-tree header")
+
+    /* Set file pointer for this v2 B-tree open context */
+    bt2->f = f;
 
     /* Set the return value */
-    ret_value = hdr;
+    ret_value = bt2;
 
 done:
-    if(!ret_value && hdr) 
-        if(H5B2_close(hdr, dxpl_id) < 0)
-            HDONE_ERROR(H5E_BTREE, H5E_CANTCLOSEOBJ, NULL, "unable to close B-tree")
+    if(hdr && H5AC_unprotect(f, dxpl_id, H5AC_BT2_HDR, addr, hdr, H5AC__NO_FLAGS_SET) < 0)
+        HDONE_ERROR(H5E_BTREE, H5E_CANTUNPROTECT, NULL, "unable to release v2 B-tree header")
+    if(!ret_value && bt2) 
+        if(H5B2_close(bt2, dxpl_id) < 0)
+            HDONE_ERROR(H5E_BTREE, H5E_CANTCLOSEOBJ, NULL, "unable to close v2 B-tree")
 
     FUNC_LEAVE_NOAPI(ret_value)
 } /* H5B2_open() */
@@ -184,23 +207,30 @@ done:
  *-------------------------------------------------------------------------
  */
 herr_t
-H5B2_insert(H5F_t *f, hid_t dxpl_id, const H5B2_class_t *type, haddr_t addr,
+H5B2_insert(H5F_t *f, hid_t dxpl_id, const H5B2_class_t *cls, haddr_t addr,
            void *udata)
 {
-    H5B2_hdr_t	*hdr = NULL;            /* Pointer to the B-tree header */
+    H5B2_t	*bt2 = NULL;            /* Pointer to the B-tree */
+    H5B2_hdr_t	*hdr;                   /* Pointer to the B-tree header */
     herr_t	ret_value = SUCCEED;    /* Return value */
 
     FUNC_ENTER_NOAPI(H5B2_insert, FAIL)
 
     /* Check arguments. */
     HDassert(f);
-    HDassert(type);
+    HDassert(cls);
     HDassert(H5F_addr_defined(addr));
 
-    /* Open the B-tree header */
-    if(NULL == (hdr = H5B2_open(f, dxpl_id, type, addr, H5AC_WRITE)))
+    /* Open the B-tree */
+    if(NULL == (bt2 = H5B2_open(f, dxpl_id, cls, addr)))
 	HGOTO_ERROR(H5E_BTREE, H5E_CANTOPENOBJ, FAIL, "unable to open B-tree")
 
+    /* Set the shared v2 B-tree header's file context for this operation */
+    bt2->hdr->f = bt2->f;
+
+    /* Get the v2 B-tree header */
+    hdr = bt2->hdr;
+
     /* Check if the root node is allocated yet */
     if(!H5F_addr_defined(hdr->root.addr)) {
         /* Create root node as leaf node in B-tree */
@@ -230,7 +260,7 @@ H5B2_insert(H5F_t *f, hid_t dxpl_id, const H5B2_class_t *type, haddr_t addr,
 
 done:
     /* Close the B-tree */
-    if(hdr && H5B2_close(hdr, dxpl_id) < 0)
+    if(bt2 && H5B2_close(bt2, dxpl_id) < 0)
         HDONE_ERROR(H5E_BTREE, H5E_CANTCLOSEOBJ, FAIL, "unable to close B-tree")
 
     FUNC_LEAVE_NOAPI(ret_value)
@@ -255,24 +285,31 @@ done:
  *-------------------------------------------------------------------------
  */
 herr_t
-H5B2_iterate(H5F_t *f, hid_t dxpl_id, const H5B2_class_t *type, haddr_t addr,
+H5B2_iterate(H5F_t *f, hid_t dxpl_id, const H5B2_class_t *cls, haddr_t addr,
     H5B2_operator_t op, void *op_data)
 {
-    H5B2_hdr_t	*hdr = NULL;            /* Pointer to the B-tree header */
+    H5B2_t	*bt2 = NULL;            /* Pointer to the B-tree */
+    H5B2_hdr_t	*hdr;                   /* Pointer to the B-tree header */
     herr_t	ret_value = SUCCEED;    /* Return value */
 
     FUNC_ENTER_NOAPI(H5B2_iterate, FAIL)
 
     /* Check arguments. */
     HDassert(f);
-    HDassert(type);
+    HDassert(cls);
     HDassert(H5F_addr_defined(addr));
     HDassert(op);
 
-    /* Open the B-tree header */
-    if(NULL == (hdr = H5B2_open(f, dxpl_id, type, addr, H5AC_READ)))
+    /* Open the B-tree */
+    if(NULL == (bt2 = H5B2_open(f, dxpl_id, cls, addr)))
 	HGOTO_ERROR(H5E_BTREE, H5E_CANTOPENOBJ, FAIL, "unable to open B-tree")
 
+    /* Set the shared v2 B-tree header's file context for this operation */
+    bt2->hdr->f = bt2->f;
+
+    /* Get the v2 B-tree header */
+    hdr = bt2->hdr;
+
     /* Iterate through records */
     if(hdr->root.node_nrec > 0) {
         /* Iterate through nodes */
@@ -282,7 +319,7 @@ H5B2_iterate(H5F_t *f, hid_t dxpl_id, const H5B2_class_t *type, haddr_t addr,
 
 done:
     /* Close the B-tree */
-    if(hdr && H5B2_close(hdr, dxpl_id) < 0)
+    if(bt2 && H5B2_close(bt2, dxpl_id) < 0)
         HDONE_ERROR(H5E_BTREE, H5E_CANTCLOSEOBJ, FAIL, "unable to close B-tree")
 
     FUNC_LEAVE_NOAPI(ret_value)
@@ -313,10 +350,11 @@ done:
  *-------------------------------------------------------------------------
  */
 htri_t
-H5B2_find(H5F_t *f, hid_t dxpl_id, const H5B2_class_t *type, haddr_t addr,
+H5B2_find(H5F_t *f, hid_t dxpl_id, const H5B2_class_t *cls, haddr_t addr,
     void *udata, H5B2_found_t op, void *op_data)
 {
-    H5B2_hdr_t	*hdr = NULL;            /* Pointer to the B-tree header */
+    H5B2_t	*bt2 = NULL;            /* Pointer to the B-tree */
+    H5B2_hdr_t	*hdr;                   /* Pointer to the B-tree header */
     H5B2_node_ptr_t curr_node_ptr;      /* Node pointer info for current node */
     unsigned    depth;                  /* Current depth of the tree */
     int         cmp;                    /* Comparison value of records */
@@ -327,13 +365,19 @@ H5B2_find(H5F_t *f, hid_t dxpl_id, const H5B2_class_t *type, haddr_t addr,
 
     /* Check arguments. */
     HDassert(f);
-    HDassert(type);
+    HDassert(cls);
     HDassert(H5F_addr_defined(addr));
 
-    /* Open the B-tree header */
-    if(NULL == (hdr = H5B2_open(f, dxpl_id, type, addr, H5AC_READ)))
+    /* Open the B-tree */
+    if(NULL == (bt2 = H5B2_open(f, dxpl_id, cls, addr)))
 	HGOTO_ERROR(H5E_BTREE, H5E_CANTOPENOBJ, FAIL, "unable to open B-tree")
 
+    /* Set the shared v2 B-tree header's file context for this operation */
+    bt2->hdr->f = bt2->f;
+
+    /* Get the v2 B-tree header */
+    hdr = bt2->hdr;
+
     /* Make copy of the root node pointer to start search with */
     curr_node_ptr = hdr->root;
 
@@ -428,7 +472,7 @@ H5B2_find(H5F_t *f, hid_t dxpl_id, const H5B2_class_t *type, haddr_t addr,
 
 done:
     /* Close the B-tree */
-    if(hdr && H5B2_close(hdr, dxpl_id) < 0)
+    if(bt2 && H5B2_close(bt2, dxpl_id) < 0)
         HDONE_ERROR(H5E_BTREE, H5E_CANTCLOSEOBJ, FAIL, "unable to close B-tree")
 
     FUNC_LEAVE_NOAPI(ret_value)
@@ -454,10 +498,11 @@ done:
  *-------------------------------------------------------------------------
  */
 herr_t
-H5B2_index(H5F_t *f, hid_t dxpl_id, const H5B2_class_t *type, haddr_t addr,
+H5B2_index(H5F_t *f, hid_t dxpl_id, const H5B2_class_t *cls, haddr_t addr,
     H5_iter_order_t order, hsize_t idx, H5B2_found_t op, void *op_data)
 {
-    H5B2_hdr_t	*hdr = NULL;            /* Pointer to the B-tree header */
+    H5B2_t	*bt2 = NULL;            /* Pointer to the B-tree */
+    H5B2_hdr_t	*hdr;                   /* Pointer to the B-tree header */
     H5B2_node_ptr_t curr_node_ptr;      /* Node pointer info for current node */
     unsigned    depth;                  /* Current depth of the tree */
     herr_t	ret_value = SUCCEED;    /* Return value */
@@ -466,14 +511,20 @@ H5B2_index(H5F_t *f, hid_t dxpl_id, const H5B2_class_t *type, haddr_t addr,
 
     /* Check arguments. */
     HDassert(f);
-    HDassert(type);
+    HDassert(cls);
     HDassert(H5F_addr_defined(addr));
     HDassert(op);
 
-    /* Open the B-tree header */
-    if(NULL == (hdr = H5B2_open(f, dxpl_id, type, addr, H5AC_READ)))
+    /* Open the B-tree */
+    if(NULL == (bt2 = H5B2_open(f, dxpl_id, cls, addr)))
 	HGOTO_ERROR(H5E_BTREE, H5E_CANTOPENOBJ, FAIL, "unable to open B-tree")
 
+    /* Set the shared v2 B-tree header's file context for this operation */
+    bt2->hdr->f = bt2->f;
+
+    /* Get the v2 B-tree header */
+    hdr = bt2->hdr;
+
     /* Make copy of the root node pointer to start search with */
     curr_node_ptr = hdr->root;
 
@@ -593,7 +644,7 @@ H5B2_index(H5F_t *f, hid_t dxpl_id, const H5B2_class_t *type, haddr_t addr,
 
 done:
     /* Close the B-tree */
-    if(hdr && H5B2_close(hdr, dxpl_id) < 0)
+    if(bt2 && H5B2_close(bt2, dxpl_id) < 0)
         HDONE_ERROR(H5E_BTREE, H5E_CANTCLOSEOBJ, FAIL, "unable to close B-tree")
 
     FUNC_LEAVE_NOAPI(ret_value)
@@ -614,23 +665,30 @@ done:
  *-------------------------------------------------------------------------
  */
 herr_t
-H5B2_remove(H5F_t *f, hid_t dxpl_id, const H5B2_class_t *type, haddr_t addr,
+H5B2_remove(H5F_t *f, hid_t dxpl_id, const H5B2_class_t *cls, haddr_t addr,
     void *udata, H5B2_remove_t op, void *op_data)
 {
-    H5B2_hdr_t	*hdr = NULL;            /* Pointer to the B-tree header */
+    H5B2_t	*bt2 = NULL;            /* Pointer to the B-tree */
+    H5B2_hdr_t	*hdr;                   /* Pointer to the B-tree header */
     herr_t	ret_value = SUCCEED;    /* Return value */
 
     FUNC_ENTER_NOAPI(H5B2_remove, FAIL)
 
     /* Check arguments. */
     HDassert(f);
-    HDassert(type);
+    HDassert(cls);
     HDassert(H5F_addr_defined(addr));
 
-    /* Open the B-tree header */
-    if(NULL == (hdr = H5B2_open(f, dxpl_id, type, addr, H5AC_WRITE)))
+    /* Open the B-tree */
+    if(NULL == (bt2 = H5B2_open(f, dxpl_id, cls, addr)))
 	HGOTO_ERROR(H5E_BTREE, H5E_CANTOPENOBJ, FAIL, "unable to open B-tree")
 
+    /* Set the shared v2 B-tree header's file context for this operation */
+    bt2->hdr->f = bt2->f;
+
+    /* Get the v2 B-tree header */
+    hdr = bt2->hdr;
+
     /* Check for empty B-tree */
     if(0 == hdr->root.all_nrec)
         HGOTO_ERROR(H5E_BTREE, H5E_NOTFOUND, FAIL, "record is not in B-tree")
@@ -670,7 +728,7 @@ H5B2_remove(H5F_t *f, hid_t dxpl_id, const H5B2_class_t *type, haddr_t addr,
 
 done:
     /* Close the B-tree */
-    if(hdr && H5B2_close(hdr, dxpl_id) < 0)
+    if(bt2 && H5B2_close(bt2, dxpl_id) < 0)
         HDONE_ERROR(H5E_BTREE, H5E_CANTCLOSEOBJ, FAIL, "unable to close B-tree")
 
     FUNC_LEAVE_NOAPI(ret_value)
@@ -691,24 +749,31 @@ done:
  *-------------------------------------------------------------------------
  */
 herr_t
-H5B2_remove_by_idx(H5F_t *f, hid_t dxpl_id, const H5B2_class_t *type,
+H5B2_remove_by_idx(H5F_t *f, hid_t dxpl_id, const H5B2_class_t *cls,
     haddr_t addr, H5_iter_order_t order, hsize_t idx, H5B2_remove_t op,
     void *op_data)
 {
-    H5B2_hdr_t	*hdr = NULL;            /* Pointer to the B-tree header */
+    H5B2_t	*bt2 = NULL;            /* Pointer to the B-tree */
+    H5B2_hdr_t	*hdr;                   /* Pointer to the B-tree header */
     herr_t	ret_value = SUCCEED;    /* Return value */
 
     FUNC_ENTER_NOAPI(H5B2_remove_by_idx, FAIL)
 
     /* Check arguments. */
     HDassert(f);
-    HDassert(type);
+    HDassert(cls);
     HDassert(H5F_addr_defined(addr));
 
-    /* Open the B-tree header */
-    if(NULL == (hdr = H5B2_open(f, dxpl_id, type, addr, H5AC_WRITE)))
+    /* Open the B-tree */
+    if(NULL == (bt2 = H5B2_open(f, dxpl_id, cls, addr)))
 	HGOTO_ERROR(H5E_BTREE, H5E_CANTOPENOBJ, FAIL, "unable to open B-tree")
 
+    /* Set the shared v2 B-tree header's file context for this operation */
+    bt2->hdr->f = bt2->f;
+
+    /* Get the v2 B-tree header */
+    hdr = bt2->hdr;
+
     /* Check for empty B-tree */
     if(0 == hdr->root.all_nrec)
         HGOTO_ERROR(H5E_BTREE, H5E_NOTFOUND, FAIL, "record is not in B-tree")
@@ -756,7 +821,7 @@ H5B2_remove_by_idx(H5F_t *f, hid_t dxpl_id, const H5B2_class_t *type,
 
 done:
     /* Close the B-tree */
-    if(hdr && H5B2_close(hdr, dxpl_id) < 0)
+    if(bt2 && H5B2_close(bt2, dxpl_id) < 0)
         HDONE_ERROR(H5E_BTREE, H5E_CANTCLOSEOBJ, FAIL, "unable to close B-tree")
 
     FUNC_LEAVE_NOAPI(ret_value)
@@ -777,30 +842,37 @@ done:
  *-------------------------------------------------------------------------
  */
 herr_t
-H5B2_get_nrec(H5F_t *f, hid_t dxpl_id, const H5B2_class_t *type, haddr_t addr,
+H5B2_get_nrec(H5F_t *f, hid_t dxpl_id, const H5B2_class_t *cls, haddr_t addr,
            hsize_t *nrec)
 {
-    H5B2_hdr_t	*hdr = NULL;            /* Pointer to the B-tree header */
+    H5B2_t	*bt2 = NULL;            /* Pointer to the B-tree */
+    H5B2_hdr_t	*hdr;                   /* Pointer to the B-tree header */
     herr_t	ret_value = SUCCEED;    /* Return value */
 
     FUNC_ENTER_NOAPI(H5B2_get_nrec, FAIL)
 
     /* Check arguments. */
     HDassert(f);
-    HDassert(type);
+    HDassert(cls);
     HDassert(H5F_addr_defined(addr));
     HDassert(nrec);
 
-    /* Open the B-tree header */
-    if(NULL == (hdr = H5B2_open(f, dxpl_id, type, addr, H5AC_READ)))
+    /* Open the B-tree */
+    if(NULL == (bt2 = H5B2_open(f, dxpl_id, cls, addr)))
 	HGOTO_ERROR(H5E_BTREE, H5E_CANTOPENOBJ, FAIL, "unable to open B-tree")
 
+    /* Set the shared v2 B-tree header's file context for this operation */
+    bt2->hdr->f = bt2->f;
+
+    /* Get the v2 B-tree header */
+    hdr = bt2->hdr;
+
     /* Get B-tree number of records */
     *nrec = hdr->root.all_nrec;
 
 done:
     /* Close the B-tree */
-    if(hdr && H5B2_close(hdr, dxpl_id) < 0)
+    if(bt2 && H5B2_close(bt2, dxpl_id) < 0)
         HDONE_ERROR(H5E_BTREE, H5E_CANTCLOSEOBJ, FAIL, "unable to close B-tree")
 
     FUNC_LEAVE_NOAPI(ret_value)
@@ -833,24 +905,31 @@ done:
  *-------------------------------------------------------------------------
  */
 herr_t
-H5B2_neighbor(H5F_t *f, hid_t dxpl_id, const H5B2_class_t *type, haddr_t addr,
+H5B2_neighbor(H5F_t *f, hid_t dxpl_id, const H5B2_class_t *cls, haddr_t addr,
     H5B2_compare_t range, void *udata, H5B2_found_t op, void *op_data)
 {
-    H5B2_hdr_t	*hdr = NULL;              /* Pointer to the B-tree header */
+    H5B2_t	*bt2 = NULL;            /* Pointer to the B-tree */
+    H5B2_hdr_t	*hdr;                   /* Pointer to the B-tree header */
     herr_t	ret_value = SUCCEED;    /* Return value */
 
     FUNC_ENTER_NOAPI(H5B2_neighbor, FAIL)
 
     /* Check arguments. */
     HDassert(f);
-    HDassert(type);
+    HDassert(cls);
     HDassert(H5F_addr_defined(addr));
     HDassert(op);
 
-    /* Open the B-tree header */
-    if(NULL == (hdr = H5B2_open(f, dxpl_id, type, addr, H5AC_READ)))
+    /* Open the B-tree */
+    if(NULL == (bt2 = H5B2_open(f, dxpl_id, cls, addr)))
 	HGOTO_ERROR(H5E_BTREE, H5E_CANTOPENOBJ, FAIL, "unable to open B-tree")
 
+    /* Set the shared v2 B-tree header's file context for this operation */
+    bt2->hdr->f = bt2->f;
+
+    /* Get the v2 B-tree header */
+    hdr = bt2->hdr;
+
     /* Check for empty tree */
     if(!H5F_addr_defined(hdr->root.addr))
         HGOTO_ERROR(H5E_BTREE, H5E_NOTFOUND, FAIL, "B-tree has no records")
@@ -867,7 +946,7 @@ H5B2_neighbor(H5F_t *f, hid_t dxpl_id, const H5B2_class_t *type, haddr_t addr,
 
 done:
     /* Close the B-tree */
-    if(hdr && H5B2_close(hdr, dxpl_id) < 0)
+    if(bt2 && H5B2_close(bt2, dxpl_id) < 0)
         HDONE_ERROR(H5E_BTREE, H5E_CANTCLOSEOBJ, FAIL, "unable to close B-tree")
 
     FUNC_LEAVE_NOAPI(ret_value)
@@ -875,64 +954,6 @@ done:
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5B2_delete
- *
- * Purpose:	Delete an entire B-tree from a file.
- *
- *              The 'OP' routine is called for each record and the
- *              OP_DATA pointer, to allow caller to perform an operation as
- *              each record is removed from the B-tree.
- *
- *              If 'OP' is NULL, the records are just removed in the process
- *              of deleting the B-tree.
- *
- * Note:	The records are _not_ guaranteed to be visited in order.
- *
- * Return:	Non-negative on success, negative on failure.
- *
- * Programmer:	Quincey Koziol
- *		koziol@ncsa.uiuc.edu
- *		Mar  9 2005
- *
- *-------------------------------------------------------------------------
- */
-herr_t
-H5B2_delete(H5F_t *f, hid_t dxpl_id, const H5B2_class_t *type, haddr_t addr,
-    H5B2_remove_t op, void *op_data)
-{
-    H5B2_hdr_t	*hdr = NULL;            /* Pointer to the B-tree header */
-    herr_t	ret_value = SUCCEED;    /* Return value */
-
-    FUNC_ENTER_NOAPI(H5B2_delete, FAIL)
-
-    /* Check arguments. */
-    HDassert(f);
-    HDassert(type);
-    HDassert(H5F_addr_defined(addr));
-
-    /* Open the B-tree header */
-    if(NULL == (hdr = H5B2_open(f, dxpl_id, type, addr, H5AC_WRITE)))
-	HGOTO_ERROR(H5E_BTREE, H5E_CANTOPENOBJ, FAIL, "unable to open B-tree")
-
-    /* Delete all nodes in B-tree */
-    if(H5F_addr_defined(hdr->root.addr))
-        if(H5B2_delete_node(f, dxpl_id, hdr, hdr->depth, &hdr->root, op, op_data) < 0)
-            HGOTO_ERROR(H5E_BTREE, H5E_CANTDELETE, FAIL, "unable to delete B-tree nodes")
-
-    /* Mark B-tree header for deletion */
-    if(H5B2_hdr_delete(hdr) < 0)
-        HGOTO_ERROR(H5E_BTREE, H5E_CANTDELETE, FAIL, "unable to mark B-tree header for deletion")
-
-done:
-    /* Close the B-tree */
-    if(hdr && H5B2_close(hdr, dxpl_id) < 0)
-        HDONE_ERROR(H5E_BTREE, H5E_CANTCLOSEOBJ, FAIL, "unable to close B-tree")
-
-    FUNC_LEAVE_NOAPI(ret_value)
-} /* H5B2_delete() */
-
-
-/*-------------------------------------------------------------------------
  * Function:	H5B2_modify
  *
  * Purpose:	Locate the specified information in a B-tree and modify it.
@@ -953,10 +974,11 @@ done:
  *-------------------------------------------------------------------------
  */
 herr_t
-H5B2_modify(H5F_t *f, hid_t dxpl_id, const H5B2_class_t *type, haddr_t addr,
+H5B2_modify(H5F_t *f, hid_t dxpl_id, const H5B2_class_t *cls, haddr_t addr,
     void *udata, H5B2_modify_t op, void *op_data)
 {
-    H5B2_hdr_t	*hdr = NULL;            /* Pointer to the B-tree header */
+    H5B2_t	*bt2 = NULL;            /* Pointer to the B-tree */
+    H5B2_hdr_t	*hdr;                   /* Pointer to the B-tree header */
     H5B2_node_ptr_t curr_node_ptr;      /* Node pointer info for current node */
     unsigned    depth;                  /* Current depth of the tree */
     int         cmp;                    /* Comparison value of records */
@@ -967,14 +989,20 @@ H5B2_modify(H5F_t *f, hid_t dxpl_id, const H5B2_class_t *type, haddr_t addr,
 
     /* Check arguments. */
     HDassert(f);
-    HDassert(type);
+    HDassert(cls);
     HDassert(H5F_addr_defined(addr));
     HDassert(op);
 
-    /* Open the B-tree header */
-    if(NULL == (hdr = H5B2_open(f, dxpl_id, type, addr, H5AC_READ)))
+    /* Open the B-tree */
+    if(NULL == (bt2 = H5B2_open(f, dxpl_id, cls, addr)))
 	HGOTO_ERROR(H5E_BTREE, H5E_CANTOPENOBJ, FAIL, "unable to open B-tree")
 
+    /* Set the shared v2 B-tree header's file context for this operation */
+    bt2->hdr->f = bt2->f;
+
+    /* Get the v2 B-tree header */
+    hdr = bt2->hdr;
+
     /* Make copy of the root node pointer to start search with */
     curr_node_ptr = hdr->root;
 
@@ -1092,7 +1120,7 @@ H5B2_modify(H5F_t *f, hid_t dxpl_id, const H5B2_class_t *type, haddr_t addr,
 
 done:
     /* Close the B-tree */
-    if(hdr && H5B2_close(hdr, dxpl_id) < 0)
+    if(bt2 && H5B2_close(bt2, dxpl_id) < 0)
         HDONE_ERROR(H5E_BTREE, H5E_CANTCLOSEOBJ, FAIL, "unable to close B-tree")
 
     FUNC_LEAVE_NOAPI(ret_value)
@@ -1113,23 +1141,30 @@ done:
  *-------------------------------------------------------------------------
  */
 herr_t
-H5B2_iterate_size(H5F_t *f, hid_t dxpl_id, const H5B2_class_t *type, haddr_t addr, hsize_t *btree_size)
+H5B2_iterate_size(H5F_t *f, hid_t dxpl_id, const H5B2_class_t *cls, haddr_t addr, hsize_t *btree_size)
 {
-    H5B2_hdr_t      	*hdr = NULL;        /* Pointer to the B-tree header */
-    herr_t      	ret_value = SUCCEED;/* Return value */
+    H5B2_t	*bt2 = NULL;            /* Pointer to the B-tree */
+    H5B2_hdr_t	*hdr;                   /* Pointer to the B-tree header */
+    herr_t      ret_value = SUCCEED;    /* Return value */
 
     FUNC_ENTER_NOAPI(H5B2_iterate_size, FAIL)
 
     /* Check arguments. */
     HDassert(f);
-    HDassert(type);
+    HDassert(cls);
     HDassert(H5F_addr_defined(addr));
     HDassert(btree_size);
 
-    /* Open the B-tree header */
-    if(NULL == (hdr = H5B2_open(f, dxpl_id, type, addr, H5AC_READ)))
+    /* Open the B-tree */
+    if(NULL == (bt2 = H5B2_open(f, dxpl_id, cls, addr)))
 	HGOTO_ERROR(H5E_BTREE, H5E_CANTOPENOBJ, FAIL, "unable to open B-tree")
 
+    /* Set the shared v2 B-tree header's file context for this operation */
+    bt2->hdr->f = bt2->f;
+
+    /* Get the v2 B-tree header */
+    hdr = bt2->hdr;
+
     /* Add size of header to B-tree metadata total */
     *btree_size += H5B2_HEADER_SIZE(f);
 
@@ -1146,7 +1181,7 @@ H5B2_iterate_size(H5F_t *f, hid_t dxpl_id, const H5B2_class_t *type, haddr_t add
 
 done:
     /* Close the B-tree */
-    if(hdr && H5B2_close(hdr, dxpl_id) < 0)
+    if(bt2 && H5B2_close(bt2, dxpl_id) < 0)
         HDONE_ERROR(H5E_BTREE, H5E_CANTCLOSEOBJ, FAIL, "unable to close B-tree")
 
     FUNC_LEAVE_NOAPI(ret_value)
@@ -1167,27 +1202,136 @@ done:
  *-------------------------------------------------------------------------
  */
 static herr_t
-H5B2_close(H5B2_hdr_t *hdr, hid_t dxpl_id)
+H5B2_close(H5B2_t *bt2, hid_t dxpl_id)
 {
-    unsigned    hdr_flags = H5AC__NO_FLAGS_SET;   /* Metadata cache flags for unprotecting header */
-    herr_t	ret_value = SUCCEED;    /* Return value */
+    const H5B2_class_t *cls = NULL;     /* Class of v2 B-tree client */
+    haddr_t bt2_addr = HADDR_UNDEF;     /* Address of v2 B-tree (for deletion) */
+    hbool_t pending_delete = FALSE;     /* Whether the v2 B-tree is pending deletion */
+    herr_t ret_value = SUCCEED;         /* Return value */
 
     FUNC_ENTER_NOAPI_NOINIT(H5B2_close)
 
     /* Check arguments. */
-    HDassert(hdr);
-    HDassert(hdr->f);
-    HDassert(H5F_addr_defined(hdr->addr));
+    HDassert(bt2);
+    HDassert(bt2->f);
+
+    /* Decrement file reference & check if this is the last open v2 B-tree using the shared B-tree header */
+    if(0 == H5B2_hdr_fuse_decr(bt2->hdr)) {
+        /* Set the shared v2 B-tree header's file context for this operation */
+        bt2->hdr->f = bt2->f;
+
+        /* Check for pending B-tree deletion */
+        if(bt2->hdr->pending_delete) {
+            /* Set local info, so B-tree deletion can occur after decrementing the
+             *  header's ref count
+             */
+            pending_delete = TRUE;
+            bt2_addr = bt2->hdr->addr;
+            cls = bt2->hdr->cls;
+        } /* end if */
+    } /* end if */
 
-    /* Check if we are supposed to delete the header */
-    if(hdr->pending_delete)
-        hdr_flags = H5AC__DIRTIED_FLAG | H5AC__DELETED_FLAG | H5AC__FREE_FILE_SPACE_FLAG;
+    /* Decrement the reference count on the B-tree header */
+    /* (don't put in H5B2_hdr_fuse_decr() as the B-tree header may be evicted
+     *  immediately -QAK)
+     */
+    if(H5B2_hdr_decr(bt2->hdr) < 0)
+        HGOTO_ERROR(H5E_BTREE, H5E_CANTDEC, FAIL, "can't decrement reference count on shared v2 B-tree header")
+
+    /* Check for pending v2 B-tree deletion */
+    if(pending_delete) {
+        H5B2_hdr_t *hdr;            /* Another pointer to v2 B-tree header */
 
-    /* Release the B-tree header info */
-    if(H5AC_unprotect(hdr->f, dxpl_id, H5AC_BT2_HDR, hdr->addr, hdr, hdr_flags) < 0)
-        HGOTO_ERROR(H5E_BTREE, H5E_CANTUNPROTECT, FAIL, "unable to release B-tree header")
+        /* Sanity check */
+        HDassert(H5F_addr_defined(bt2_addr));
+        HDassert(cls);
+
+        /* Lock the v2 B-tree header into memory */
+        if(NULL == (hdr = (H5B2_hdr_t *)H5AC_protect(bt2->f, dxpl_id, H5AC_BT2_HDR, bt2_addr, cls, NULL, H5AC_WRITE)))
+            HGOTO_ERROR(H5E_BTREE, H5E_CANTLOAD, FAIL, "unable to load v2 B-tree header")
+
+        /* Set the shared v2 B-tree header's file context for this operation */
+        hdr->f = bt2->f;
+
+        /* Delete v2 B-tree, starting with header (unprotects header) */
+        if(H5B2_hdr_delete(hdr, dxpl_id) < 0)
+            HGOTO_ERROR(H5E_BTREE, H5E_CANTDELETE, FAIL, "unable to delete v2 B-tree")
+    } /* end if */
+
+    /* Release the v2 B-tree wrapper */
+    bt2 = H5FL_FREE(H5B2_t, bt2);
 
 done:
     FUNC_LEAVE_NOAPI(ret_value)
 } /* H5B2_close() */
 
+
+/*-------------------------------------------------------------------------
+ * Function:	H5B2_delete
+ *
+ * Purpose:	Delete an entire B-tree from a file.
+ *
+ *              The 'OP' routine is called for each record and the
+ *              OP_DATA pointer, to allow caller to perform an operation as
+ *              each record is removed from the B-tree.
+ *
+ *              If 'OP' is NULL, the records are just removed in the process
+ *              of deleting the B-tree.
+ *
+ * Note:	The records are _not_ guaranteed to be visited in order.
+ *
+ * Return:	Non-negative on success, negative on failure.
+ *
+ * Programmer:	Quincey Koziol
+ *		koziol@ncsa.uiuc.edu
+ *		Mar  9 2005
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5B2_delete(H5F_t *f, hid_t dxpl_id, const H5B2_class_t *cls, haddr_t addr,
+    H5B2_remove_t op, void *op_data)
+{
+    H5B2_hdr_t	*hdr = NULL;            /* Pointer to the B-tree header */
+    herr_t	ret_value = SUCCEED;    /* Return value */
+
+    FUNC_ENTER_NOAPI(H5B2_delete, FAIL)
+
+    /* Check arguments. */
+    HDassert(f);
+    HDassert(cls);
+    HDassert(H5F_addr_defined(addr));
+
+    /* Lock the v2 B-tree header into memory */
+#ifdef QAK
+HDfprintf(stderr, "%s: addr = %a\n", FUNC, addr);
+#endif /* QAK */
+    if(NULL == (hdr = (H5B2_hdr_t *)H5AC_protect(f, dxpl_id, H5AC_BT2_HDR, addr, cls, NULL, H5AC_WRITE)))
+        HGOTO_ERROR(H5E_BTREE, H5E_CANTLOAD, FAIL, "unable to load v2 B-tree header")
+
+    /* Remember the callback & context for later */
+    hdr->remove_op = op;
+    hdr->remove_op_data = op_data;
+
+    /* Check for files using shared v2 B-tree header */
+    if(hdr->file_rc)
+        hdr->pending_delete = TRUE;
+    else {
+        /* Set the shared v2 B-tree header's file context for this operation */
+        hdr->f = f;
+
+        /* Delete v2 B-tree now, starting with header (unprotects header) */
+        if(H5B2_hdr_delete(hdr, dxpl_id) < 0)
+            HGOTO_ERROR(H5E_BTREE, H5E_CANTDELETE, FAIL, "unable to delete v2 B-tree")
+        hdr = NULL;
+    } /* end if */
+
+done:
+    /* Unprotect the header, if an error occurred */
+    if(hdr && H5AC_unprotect(f, dxpl_id, H5AC_BT2_HDR, addr, hdr, H5AC__NO_FLAGS_SET) < 0)
+        HDONE_ERROR(H5E_BTREE, H5E_CANTUNPROTECT, FAIL, "unable to release v2 B-tree header")
+
+
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* H5B2_delete() */
+
diff --git a/src/H5B2cache.c b/src/H5B2cache.c
index 859554e..aa39adb 100644
--- a/src/H5B2cache.c
+++ b/src/H5B2cache.c
@@ -170,7 +170,7 @@ H5B2_cache_hdr_load(H5F_t *f, hid_t dxpl_id, haddr_t addr, const void *_cls, voi
     HDassert(cls);
 
     /* Allocate new B-tree header and reset cache info */
-    if(NULL == (hdr = H5B2_hdr_alloc()))
+    if(NULL == (hdr = H5B2_hdr_alloc(f)))
 	HGOTO_ERROR(H5E_BTREE, H5E_CANTALLOC, NULL, "allocation failed for B-tree header")
 
     /* Wrap the local buffer for serialized header info */
@@ -730,6 +730,7 @@ H5B2_cache_internal_dest(H5F_t *f, H5B2_internal_t *internal)
     /*
      * Check arguments.
      */
+    HDassert(f);
     HDassert(internal);
     HDassert(internal->hdr);
 
@@ -1052,6 +1053,7 @@ H5B2_cache_leaf_dest(H5F_t *f, H5B2_leaf_t *leaf)
     /*
      * Check arguments.
      */
+    HDassert(f);
     HDassert(leaf);
     HDassert(leaf->hdr);
 
diff --git a/src/H5B2hdr.c b/src/H5B2hdr.c
index 489d047..95bafdd 100644
--- a/src/H5B2hdr.c
+++ b/src/H5B2hdr.c
@@ -230,18 +230,24 @@ done:
  *-------------------------------------------------------------------------
  */
 H5B2_hdr_t *
-H5B2_hdr_alloc(void)
+H5B2_hdr_alloc(H5F_t *f)
 {
     H5B2_hdr_t *hdr = NULL;             /* v2 B-tree header */
     H5B2_hdr_t *ret_value;              /* Return value */
 
     FUNC_ENTER_NOAPI_NOINIT(H5B2_hdr_alloc)
 
+    /*
+     * Check arguments.
+     */
+    HDassert(f);
+
     /* Allocate space for the shared information */
     if(NULL == (hdr = H5FL_CALLOC(H5B2_hdr_t)))
 	HGOTO_ERROR(H5E_BTREE, H5E_CANTALLOC, NULL, "memory allocation failed for B-tree header")
 
     /* Assign non-zero information */
+    hdr->f = f;
     hdr->root.addr = HADDR_UNDEF;
 
     /* Set return value */
@@ -284,7 +290,7 @@ H5B2_hdr_create(H5F_t *f, hid_t dxpl_id, const H5B2_create_t *cparam)
     HDassert(cparam);
 
     /* Allocate v2 B-tree header */
-    if(NULL == (hdr = H5B2_hdr_alloc()))
+    if(NULL == (hdr = H5B2_hdr_alloc(f)))
 	HGOTO_ERROR(H5E_BTREE, H5E_CANTALLOC, HADDR_UNDEF, "allocation failed for B-tree header")
 
     /* Initialize shared B-tree info */
@@ -387,6 +393,63 @@ done:
 
 
 /*-------------------------------------------------------------------------
+ * Function:	H5B2_hdr_fuse_incr
+ *
+ * Purpose:	Increment file reference count on shared v2 B-tree header
+ *
+ * Return:	Non-negative on success/Negative on failure
+ *
+ * Programmer:	Quincey Koziol
+ *		koziol@hdfgroup.org
+ *		Oct 27 2009
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5B2_hdr_fuse_incr(H5B2_hdr_t *hdr)
+{
+    FUNC_ENTER_NOAPI_NOINIT_NOFUNC(H5B2_hdr_fuse_incr)
+
+    /* Sanity check */
+    HDassert(hdr);
+
+    /* Increment file reference count on shared header */
+    hdr->file_rc++;
+
+    FUNC_LEAVE_NOAPI(SUCCEED)
+} /* end H5B2_hdr_fuse_incr() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:	H5B2_hdr_fuse_decr
+ *
+ * Purpose:	Decrement file reference count on shared v2 B-tree header
+ *
+ * Return:	Non-negative on success/Negative on failure
+ *
+ * Programmer:	Quincey Koziol
+ *		koziol@hdfgroup.org
+ *		Oct 27 2009
+ *
+ *-------------------------------------------------------------------------
+ */
+size_t
+H5B2_hdr_fuse_decr(H5B2_hdr_t *hdr)
+{
+    FUNC_ENTER_NOAPI_NOINIT_NOFUNC(H5B2_hdr_fuse_decr)
+
+    /* Sanity check */
+    HDassert(hdr);
+    HDassert(hdr->file_rc);
+
+    /* Decrement file reference count on shared header */
+    hdr->file_rc--;
+
+    FUNC_LEAVE_NOAPI(hdr->file_rc)
+} /* end H5B2_hdr_fuse_decr() */
+
+
+/*-------------------------------------------------------------------------
  * Function:	H5B2_hdr_dirty
  *
  * Purpose:	Mark B-tree header as dirty
@@ -479,7 +542,7 @@ done:
 /*-------------------------------------------------------------------------
  * Function:	H5B2_hdr_delete
  *
- * Purpose:	Mark B-tree header for deletion
+ * Purpose:	Delete a v2 B-tree, starting with the header
  *
  * Return:	Non-negative on success/Negative on failure
  *
@@ -490,15 +553,42 @@ done:
  *-------------------------------------------------------------------------
  */
 herr_t
-H5B2_hdr_delete(H5B2_hdr_t *hdr)
+H5B2_hdr_delete(H5B2_hdr_t *hdr, hid_t dxpl_id)
 {
-    FUNC_ENTER_NOAPI_NOINIT_NOFUNC(H5B2_hdr_delete)
+    unsigned cache_flags = H5AC__NO_FLAGS_SET;  /* Flags for unprotecting v2 B-tree header */
+    herr_t ret_value = SUCCEED;         /* Return value */
+
+    FUNC_ENTER_NOAPI(H5B2_hdr_delete, FAIL)
 
     /* Sanity check */
     HDassert(hdr);
 
-    /* Mark B-tree header as pending deletion */
-    hdr->pending_delete = TRUE;
+#ifndef NDEBUG
+{
+    unsigned hdr_status = 0;         /* v2 B-tree header's status in the metadata cache */
+
+    /* Check the v2 B-tree header's status in the metadata cache */
+    if(H5AC_get_entry_status(hdr->f, hdr->addr, &hdr_status) < 0)
+        HGOTO_ERROR(H5E_BTREE, H5E_CANTGET, FAIL, "unable to check metadata cache status for v2 B-tree header")
+
+    /* Sanity checks on v2 B-tree header */
+    HDassert(hdr_status & H5AC_ES__IN_CACHE);
+    HDassert(hdr_status & H5AC_ES__IS_PROTECTED);
+} /* end block */
+#endif /* NDEBUG */
+
+    /* Delete all nodes in B-tree */
+    if(H5F_addr_defined(hdr->root.addr))
+        if(H5B2_delete_node(hdr->f, dxpl_id, hdr, hdr->depth, &hdr->root, hdr->remove_op, hdr->remove_op_data) < 0)
+            HGOTO_ERROR(H5E_BTREE, H5E_CANTDELETE, FAIL, "unable to delete B-tree nodes")
+
+    /* Indicate that the heap header should be deleted & file space freed */
+    cache_flags |= H5AC__DIRTIED_FLAG | H5AC__DELETED_FLAG | H5AC__FREE_FILE_SPACE_FLAG;
+
+done:
+    /* Unprotect the header with appropriate flags */
+    if(hdr && H5AC_unprotect(hdr->f, dxpl_id, H5AC_BT2_HDR, hdr->addr, hdr, cache_flags) < 0)
+        HDONE_ERROR(H5E_BTREE, H5E_CANTUNPROTECT, FAIL, "unable to release B-tree header")
 
     FUNC_LEAVE_NOAPI(SUCCEED)
 } /* end H5B2_hdr_delete() */
diff --git a/src/H5B2pkg.h b/src/H5B2pkg.h
index 578e39f..3961fb5 100644
--- a/src/H5B2pkg.h
+++ b/src/H5B2pkg.h
@@ -158,7 +158,10 @@ typedef struct H5B2_hdr_t {
     H5F_t       *f;             /* Pointer to the file that the B-tree is in */
     haddr_t     addr;           /* Address of B-tree header in the file */
     size_t      rc;             /* Reference count of nodes using this header */
+    size_t      file_rc;        /* Reference count of files using this header */
     hbool_t     pending_delete; /* B-tree is pending deletion */
+    H5B2_remove_t remove_op;    /* Callback operator for deleting B-tree */
+    void        *remove_op_data;/* B-tree deletion callback's context */
     const H5B2_class_t *cls;	/* Class of B-tree client */
     uint8_t	*page;	        /* Common disk page for I/O */
     size_t      *nat_off;       /* Array of offsets of native records */
@@ -189,6 +192,12 @@ typedef struct H5B2_internal_t {
     unsigned    depth;          /* Depth of this node in the B-tree           */
 } H5B2_internal_t;
 
+/* v2 B-tree */
+struct H5B2_t {
+    H5B2_hdr_t  *hdr;           /* Pointer to internal v2 B-tree header info */
+    H5F_t      *f;              /* Pointer to file for v2 B-tree */
+};
+
 /* User data for metadata cache 'load' callback */
 typedef struct {
     H5B2_hdr_t	*hdr;		/* Pointer to the [pinned] v2 B-tree header   */
@@ -235,16 +244,18 @@ H5_DLLVAR const H5B2_class_t H5B2_TEST[1];
 /******************************/
 
 /* Routines for managing B-tree header info */
-H5_DLL H5B2_hdr_t *H5B2_hdr_alloc(void);
+H5_DLL H5B2_hdr_t *H5B2_hdr_alloc(H5F_t *f);
 H5_DLL haddr_t H5B2_hdr_create(H5F_t *f, hid_t dxpl_id,
     const H5B2_create_t *cparam);
 H5_DLL herr_t H5B2_hdr_init(H5F_t *f, H5B2_hdr_t *hdr,
     const H5B2_create_t *cparam, unsigned depth);
 H5_DLL herr_t H5B2_hdr_incr(H5B2_hdr_t *hdr);
 H5_DLL herr_t H5B2_hdr_decr(H5B2_hdr_t *hdr);
+H5_DLL herr_t H5B2_hdr_fuse_incr(H5B2_hdr_t *hdr);
+H5_DLL size_t H5B2_hdr_fuse_decr(H5B2_hdr_t *hdr);
 H5_DLL herr_t H5B2_hdr_dirty(H5B2_hdr_t *hdr);
 H5_DLL herr_t H5B2_hdr_free(H5B2_hdr_t *hdr);
-H5_DLL herr_t H5B2_hdr_delete(H5B2_hdr_t *hdr);
+H5_DLL herr_t H5B2_hdr_delete(H5B2_hdr_t *hdr, hid_t dxpl_id);
 
 /* Routines for operating on internal nodes */
 H5_DLL H5B2_internal_t *H5B2_protect_internal(H5F_t *f, hid_t dxpl_id,
diff --git a/src/H5B2private.h b/src/H5B2private.h
index e99def0..481f910 100644
--- a/src/H5B2private.h
+++ b/src/H5B2private.h
@@ -116,6 +116,10 @@ typedef struct H5B2_stat_t {
     hsize_t nrecords;          /* Number of records */
 } H5B2_stat_t;
 
+/* v2 B-tree info (forward decl - defined in H5B2pkg.h) */
+typedef struct H5B2_t H5B2_t;
+
+
 /*****************************/
 /* Library-private Variables */
 /*****************************/
diff --git a/src/H5B2stat.c b/src/H5B2stat.c
index 4b97e17..5fc7659 100644
--- a/src/H5B2stat.c
+++ b/src/H5B2stat.c
@@ -85,7 +85,7 @@
  *-------------------------------------------------------------------------
  */
 herr_t
-H5B2_stat_info(H5F_t *f, hid_t dxpl_id, const H5B2_class_t *type, haddr_t addr,
+H5B2_stat_info(H5F_t *f, hid_t dxpl_id, const H5B2_class_t *cls, haddr_t addr,
     H5B2_stat_t *info)
 {
     H5B2_hdr_t	*hdr = NULL;            /* Pointer to the B-tree header */
@@ -95,12 +95,12 @@ H5B2_stat_info(H5F_t *f, hid_t dxpl_id, const H5B2_class_t *type, haddr_t addr,
 
     /* Check arguments. */
     HDassert(f);
-    HDassert(type);
+    HDassert(cls);
     HDassert(H5F_addr_defined(addr));
     HDassert(info);
 
     /* Look up the B-tree header */
-    if(NULL == (hdr = (H5B2_hdr_t *)H5AC_protect(f, dxpl_id, H5AC_BT2_HDR, addr, type, NULL, H5AC_READ)))
+    if(NULL == (hdr = (H5B2_hdr_t *)H5AC_protect(f, dxpl_id, H5AC_BT2_HDR, addr, cls, NULL, H5AC_READ)))
 	HGOTO_ERROR(H5E_BTREE, H5E_CANTPROTECT, FAIL, "unable to load B-tree header")
 
     /* Get information about the B-tree */
diff --git a/src/H5B2test.c b/src/H5B2test.c
index be0cf02..b29fde1 100644
--- a/src/H5B2test.c
+++ b/src/H5B2test.c
@@ -20,6 +20,7 @@
  *
  */
 
+
 /****************/
 /* Module Setup */
 /****************/
@@ -27,6 +28,7 @@
 #define H5B2_PACKAGE		/*suppress error about including H5B2pkg  */
 #define H5B2_TESTING		/*suppress warning about H5B2 testing funcs*/
 
+
 /***********/
 /* Headers */
 /***********/
@@ -34,6 +36,7 @@
 #include "H5B2pkg.h"		/* v2 B-trees				*/
 #include "H5Eprivate.h"		/* Error handling		  	*/
 
+
 /****************/
 /* Local Macros */
 /****************/
@@ -52,6 +55,7 @@
 /********************/
 /* Local Prototypes */
 /********************/
+
 static herr_t H5B2_test_store(void *nrecord, const void *udata);
 static herr_t H5B2_test_compare(const void *rec1, const void *rec2);
 static herr_t H5B2_test_encode(const H5F_t *f, uint8_t *raw,
@@ -61,9 +65,11 @@ static herr_t H5B2_test_decode(const H5F_t *f, const uint8_t *raw,
 static herr_t H5B2_test_debug(FILE *stream, const H5F_t *f, hid_t dxpl_id,
     int indent, int fwidth, const void *record, const void *_udata);
 
+
 /*********************/
 /* Package Variables */
 /*********************/
+
 const H5B2_class_t H5B2_TEST[1]={{   /* B-tree class information */
     H5B2_TEST_ID,               /* Type of B-tree */
     "H5B2_TEST_ID",             /* Name of B-tree class */
@@ -75,6 +81,7 @@ const H5B2_class_t H5B2_TEST[1]={{   /* B-tree class information */
     H5B2_test_debug             /* Record debugging callback */
 }};
 
+
 /*****************************/
 /* Library Private Variables */
 /*****************************/
@@ -84,6 +91,7 @@ const H5B2_class_t H5B2_TEST[1]={{   /* B-tree class information */
 /* Local Variables */
 /*******************/
 
+
 
 /*-------------------------------------------------------------------------
  * Function:	H5B2_test_store
@@ -228,7 +236,7 @@ H5B2_test_debug(FILE *stream, const H5F_t UNUSED *f, hid_t UNUSED dxpl_id,
  *-------------------------------------------------------------------------
  */
 herr_t
-H5B2_get_root_addr_test(H5F_t *f, hid_t dxpl_id, const H5B2_class_t *type,
+H5B2_get_root_addr_test(H5F_t *f, hid_t dxpl_id, const H5B2_class_t *cls,
     haddr_t addr, haddr_t *root_addr)
 {
     H5B2_hdr_t	*hdr = NULL;            /* Pointer to the B-tree header */
@@ -238,12 +246,12 @@ H5B2_get_root_addr_test(H5F_t *f, hid_t dxpl_id, const H5B2_class_t *type,
 
     /* Check arguments. */
     HDassert(f);
-    HDassert(type);
+    HDassert(cls);
     HDassert(H5F_addr_defined(addr));
     HDassert(root_addr);
 
     /* Look up the B-tree header */
-    if(NULL == (hdr = (H5B2_hdr_t *)H5AC_protect(f, dxpl_id, H5AC_BT2_HDR, addr, type, NULL, H5AC_READ)))
+    if(NULL == (hdr = (H5B2_hdr_t *)H5AC_protect(f, dxpl_id, H5AC_BT2_HDR, addr, cls, NULL, H5AC_READ)))
 	HGOTO_ERROR(H5E_BTREE, H5E_CANTPROTECT, FAIL, "unable to load B-tree header")
 
     /* Get B-tree root addr */
@@ -272,7 +280,7 @@ done:
  *-------------------------------------------------------------------------
  */
 herr_t
-H5B2_get_node_info_test(H5F_t *f, hid_t dxpl_id, const H5B2_class_t *type,
+H5B2_get_node_info_test(H5F_t *f, hid_t dxpl_id, const H5B2_class_t *cls,
     haddr_t addr, void *udata, H5B2_node_info_test_t *ninfo)
 {
     H5B2_hdr_t	*hdr = NULL;            /* Pointer to the B-tree header */
@@ -286,11 +294,11 @@ H5B2_get_node_info_test(H5F_t *f, hid_t dxpl_id, const H5B2_class_t *type,
 
     /* Check arguments. */
     HDassert(f);
-    HDassert(type);
+    HDassert(cls);
     HDassert(H5F_addr_defined(addr));
 
     /* Look up the B-tree header */
-    if(NULL == (hdr = (H5B2_hdr_t *)H5AC_protect(f, dxpl_id, H5AC_BT2_HDR, addr, type, NULL, H5AC_READ)))
+    if(NULL == (hdr = (H5B2_hdr_t *)H5AC_protect(f, dxpl_id, H5AC_BT2_HDR, addr, cls, NULL, H5AC_READ)))
 	HGOTO_ERROR(H5E_BTREE, H5E_CANTPROTECT, FAIL, "unable to load B-tree header")
 
     /* Set file pointer for this B-tree operation */
@@ -374,11 +382,8 @@ H5B2_get_node_info_test(H5F_t *f, hid_t dxpl_id, const H5B2_class_t *type,
 
 done:
     /* Release header */
-    if(hdr) {
-        hdr->f = NULL;
-        if(H5AC_unprotect(f, dxpl_id, H5AC_BT2_HDR, addr, hdr, H5AC__NO_FLAGS_SET) < 0)
-            HDONE_ERROR(H5E_BTREE, H5E_CANTUNPROTECT, FAIL, "unable to release B-tree header info")
-    } /* end if */
+    if(hdr && H5AC_unprotect(f, dxpl_id, H5AC_BT2_HDR, addr, hdr, H5AC__NO_FLAGS_SET) < 0)
+        HDONE_ERROR(H5E_BTREE, H5E_CANTUNPROTECT, FAIL, "unable to release B-tree header info")
 
     FUNC_LEAVE_NOAPI(ret_value)
 } /* H5B2_get_node_info_test() */
@@ -401,7 +406,7 @@ done:
  *-------------------------------------------------------------------------
  */
 int
-H5B2_get_node_depth_test(H5F_t *f, hid_t dxpl_id, const H5B2_class_t *type, haddr_t addr,
+H5B2_get_node_depth_test(H5F_t *f, hid_t dxpl_id, const H5B2_class_t *cls, haddr_t addr,
     void *udata)
 {
     H5B2_node_info_test_t ninfo;        /* Node information */
@@ -411,11 +416,11 @@ H5B2_get_node_depth_test(H5F_t *f, hid_t dxpl_id, const H5B2_class_t *type, hadd
 
     /* Check arguments. */
     HDassert(f);
-    HDassert(type);
+    HDassert(cls);
     HDassert(H5F_addr_defined(addr));
 
     /* Get information abou the node */
-    if(H5B2_get_node_info_test(f, dxpl_id, type, addr, udata, &ninfo) < 0)
+    if(H5B2_get_node_info_test(f, dxpl_id, cls, addr, udata, &ninfo) < 0)
         HGOTO_ERROR(H5E_BTREE, H5E_NOTFOUND, FAIL, "error looking up node info")
 
     /* Set return value */
diff --git a/src/H5HF.c b/src/H5HF.c
index 7ba6e5e..c1f0b2e 100644
--- a/src/H5HF.c
+++ b/src/H5HF.c
@@ -172,7 +172,7 @@ HDfprintf(stderr, "%s: Called\n", FUNC);
 
     /* Allocate fractal heap wrapper */
     if(NULL == (fh = H5FL_MALLOC(H5HF_t)))
-        HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, NULL, "memory allocation failed for fractal heap info")
+        HGOTO_ERROR(H5E_HEAP, H5E_CANTALLOC, NULL, "memory allocation failed for fractal heap info")
 
     /* Lock the heap header into memory */
     if(NULL == (hdr = (H5HF_hdr_t *)H5AC_protect(f, dxpl_id, H5AC_FHEAP_HDR, fh_addr, NULL, NULL, H5AC_WRITE)))
@@ -249,7 +249,7 @@ HDfprintf(stderr, "%s: hdr->rc = %u, hdr->fspace = %p\n", FUNC, hdr->rc, hdr->fs
 
     /* Create fractal heap info */
     if(NULL == (fh = H5FL_MALLOC(H5HF_t)))
-        HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, NULL, "memory allocation failed for fractal heap info")
+        HGOTO_ERROR(H5E_HEAP, H5E_CANTALLOC, NULL, "memory allocation failed for fractal heap info")
 
     /* Point fractal heap wrapper at header */
     fh->hdr = hdr;
diff --git a/src/H5HFcache.c b/src/H5HFcache.c
index b967e9d..ffa3840 100644
--- a/src/H5HFcache.c
+++ b/src/H5HFcache.c
@@ -483,9 +483,6 @@ HDfprintf(stderr, "%s: Flushing heap header, addr = %a, destroy = %u\n", FUNC, a
         uint8_t heap_flags;     /* Status flags for heap */
         uint32_t metadata_chksum; /* Computed metadata checksum value */
 
-        /* Sanity check */
-        HDassert(hdr->dirty);
-
         /* Set the shared heap header's file context for this operation */
         hdr->f = f;
 
@@ -570,7 +567,6 @@ HDfprintf(stderr, "%s: Flushing heap header, addr = %a, destroy = %u\n", FUNC, a
 	if(H5F_block_write(f, H5FD_MEM_FHEAP_HDR, addr, size, dxpl_id, buf) < 0)
 	    HGOTO_ERROR(H5E_HEAP, H5E_CANTFLUSH, FAIL, "unable to save fractal heap header to disk")
 
-	hdr->dirty = FALSE;
 	hdr->cache_info.is_dirty = FALSE;
     } /* end if */
 
diff --git a/src/H5HFhdr.c b/src/H5HFhdr.c
index b386682..c326a59 100644
--- a/src/H5HFhdr.c
+++ b/src/H5HFhdr.c
@@ -409,9 +409,6 @@ H5HF_hdr_create(H5F_t *f, hid_t dxpl_id, const H5HF_create_t *cparam)
     /* Set "huge" object tracker v2 B-tree address to indicate that there aren't any yet */
     hdr->huge_bt2_addr = HADDR_UNDEF;
 
-    /* Note that the shared info is dirty (it's not written to the file yet) */
-    hdr->dirty = TRUE;
-
     /* First phase of header final initialization */
     /* (doesn't need ID length set up) */
     if(H5HF_hdr_finish_init_phase1(hdr) < 0)
@@ -696,9 +693,6 @@ HDfprintf(stderr, "%s: Marking heap header as dirty\n", FUNC);
     if(H5AC_mark_pinned_or_protected_entry_dirty(hdr->f, hdr) < 0)
         HGOTO_ERROR(H5E_HEAP, H5E_CANTMARKDIRTY, FAIL, "unable to mark fractal heap header as dirty")
 
-    /* Set the dirty flags for the heap header */
-    hdr->dirty = TRUE;
-
 done:
     FUNC_LEAVE_NOAPI(ret_value)
 } /* end H5HF_hdr_dirty() */
diff --git a/src/H5HFpkg.h b/src/H5HFpkg.h
index 523b197..785a3ff 100644
--- a/src/H5HFpkg.h
+++ b/src/H5HFpkg.h
@@ -335,7 +335,6 @@ typedef struct H5HF_hdr_t {
 
     /* Cached/computed values (not stored in header) */
     size_t      rc;             /* Reference count of heap's components using heap header */
-    hbool_t     dirty;          /* Shared info is modified */
     haddr_t     heap_addr;      /* Address of heap header in the file */
     size_t      heap_size;      /* Size of heap header in the file */
     H5AC_protect_t mode;        /* Access mode for heap */