[svn-r22274] merge from trunk, resolve conflicts

85 files changed, 3631 insertions, 962 deletions

diff --git a/src/H5A.c b/src/H5A.c
index c59e098..0ba7361 100644
--- a/src/H5A.c
+++ b/src/H5A.c
@@ -2566,6 +2566,36 @@ done:
 
 
 /*-------------------------------------------------------------------------
+ * Function:    H5A_type
+ *
+ * Purpose:     Return the datatype for an attribute.
+ *
+ * Return:      Success:        Ptr to entry
+ *              Failure:        NULL
+ *
+ * Programmer:  Neil Fortner
+ *              Friday, November  11, 2011
+ *
+ *-------------------------------------------------------------------------
+ */
+H5T_t *
+H5A_type(const H5A_t *attr)
+{
+    H5T_t *ret_value;   /* Return value */
+
+    FUNC_ENTER_NOAPI(NULL)
+
+    HDassert(attr);
+
+    /* Set return value */
+    ret_value = attr->shared->dt;
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5A_type() */
+
+
+/*-------------------------------------------------------------------------
  * Function:	H5Aexists
  *
  * Purpose:	Checks if an attribute with a given name exists on an opened
diff --git a/src/H5Aint.c b/src/H5Aint.c
index 8475330..74c5590 100644
--- a/src/H5Aint.c
+++ b/src/H5Aint.c
@@ -795,6 +795,12 @@ H5A_set_version(const H5F_t *f, H5A_t *attr)
  *
  * Purpose:     Copies a message from _MESG to _DEST in file
  *
+ *              Note that this function assumes that it is copying *all*
+ *              the attributes in the object, specifically when it copies
+ *              the creation order from source to destination.  If this is
+ *              to be used to copy only a single attribute, then the
+ *              creation order must be handled differently.  -NAF
+ *
  * Return:      Success:        Ptr to _DEST
  *
  *              Failure:        NULL
@@ -849,6 +855,7 @@ H5A_attr_copy_file(const H5A_t *attr_src, H5F_t *file_dst, hbool_t *recompute_si
     /* Copy attribute's name */
     attr_dst->shared->name = H5MM_strdup(attr_src->shared->name);
     HDassert(attr_dst->shared->name);
+    attr_dst->shared->encoding = attr_src->shared->encoding;
 
     /* Copy attribute's datatype */
     /* If source is named, we will keep dst as named, but we will not actually
@@ -1003,6 +1010,9 @@ H5A_attr_copy_file(const H5A_t *attr_src, H5F_t *file_dst, hbool_t *recompute_si
         } /* end else */
     } /* end if(attr_src->shared->data) */
 
+    /* Copy the creation order */
+    attr_dst->shared->crt_idx = attr_src->shared->crt_idx;
+
     /* Recompute the version to encode the destination attribute */
     if(H5A_set_version(file_dst, attr_dst) < 0)
         HGOTO_ERROR(H5E_ATTR, H5E_CANTSET, NULL, "unable to update attribute version")
diff --git a/src/H5Apkg.h b/src/H5Apkg.h
index e7732e2..5257171 100644
--- a/src/H5Apkg.h
+++ b/src/H5Apkg.h
@@ -158,29 +158,6 @@ typedef struct {
     H5A_t       **attrs;        /* Pointer to array of attribute pointers */
 } H5A_attr_table_t;
 
-/* Attribute iteration operator for internal library callbacks */
-typedef herr_t (*H5A_lib_iterate_t)(const H5A_t *attr, void *op_data);
-
-/* Describe kind of callback to make for each attribute */
-typedef enum H5A_attr_iter_op_type_t {
-#ifndef H5_NO_DEPRECATED_SYMBOLS
-    H5A_ATTR_OP_APP,                /* Application callback */
-#endif /* H5_NO_DEPRECATED_SYMBOLS */
-    H5A_ATTR_OP_APP2,               /* Revised application callback */
-    H5A_ATTR_OP_LIB                 /* Library internal callback */
-} H5A_attr_iter_op_type_t;
-
-typedef struct H5A_attr_iter_op_t {
-    H5A_attr_iter_op_type_t op_type;
-    union {
-#ifndef H5_NO_DEPRECATED_SYMBOLS
-        H5A_operator1_t app_op;         /* Application callback for each attribute */
-#endif /* H5_NO_DEPRECATED_SYMBOLS */
-        H5A_operator2_t app_op2;        /* Revised application callback for each attribute */
-        H5A_lib_iterate_t lib_op;       /* Library internal callback for each attribute */
-    } u;
-} H5A_attr_iter_op_t;
-
 
 /*****************************/
 /* Package Private Variables */
@@ -274,9 +251,6 @@ H5_DLL herr_t H5O_attr_write(const H5O_loc_t *loc, hid_t dxpl_id,
     H5A_t *attr);
 H5_DLL herr_t H5O_attr_rename(const H5O_loc_t *loc, hid_t dxpl_id,
     const char *old_name, const char *new_name);
-H5_DLL herr_t H5O_attr_iterate(hid_t loc_id, hid_t dxpl_id, H5_index_t idx_type,
-    H5_iter_order_t order, hsize_t skip, hsize_t *last_attr,
-    const H5A_attr_iter_op_t *op, void *op_data);
 H5_DLL herr_t H5O_attr_remove(const H5O_loc_t *loc, const char *name,
     hid_t dxpl_id);
 H5_DLL herr_t H5O_attr_remove_by_idx(const H5O_loc_t *loc, H5_index_t idx_type,
diff --git a/src/H5Aprivate.h b/src/H5Aprivate.h
index 18219e6..ac9f698 100644
--- a/src/H5Aprivate.h
+++ b/src/H5Aprivate.h
@@ -24,6 +24,8 @@
 
 /* Private headers needed by this file */
 #include "H5Gprivate.h"		/* Groups				*/
+#include "H5Oprivate.h"         /* Object headers                       */
+#include "H5Tprivate.h"         /* Datatypes                            */
 
 
 /**************************/
@@ -41,6 +43,29 @@
 /* Forward references of package typedefs */
 typedef struct H5A_t H5A_t;
 
+/* Attribute iteration operator for internal library callbacks */
+typedef herr_t (*H5A_lib_iterate_t)(const H5A_t *attr, void *op_data);
+
+/* Describe kind of callback to make for each attribute */
+typedef enum H5A_attr_iter_op_type_t {
+#ifndef H5_NO_DEPRECATED_SYMBOLS
+    H5A_ATTR_OP_APP,                /* Application callback */
+#endif /* H5_NO_DEPRECATED_SYMBOLS */
+    H5A_ATTR_OP_APP2,               /* Revised application callback */
+    H5A_ATTR_OP_LIB                 /* Library internal callback */
+} H5A_attr_iter_op_type_t;
+
+typedef struct H5A_attr_iter_op_t {
+    H5A_attr_iter_op_type_t op_type;
+    union {
+#ifndef H5_NO_DEPRECATED_SYMBOLS
+        H5A_operator1_t app_op;         /* Application callback for each attribute */
+#endif /* H5_NO_DEPRECATED_SYMBOLS */
+        H5A_operator2_t app_op2;        /* Revised application callback for each attribute */
+        H5A_lib_iterate_t lib_op;       /* Library internal callback for each attribute */
+    } u;
+} H5A_attr_iter_op_t;
+
 
 /*****************************/
 /* Library-private Variables */
@@ -54,6 +79,13 @@ typedef struct H5A_t H5A_t;
 /* General attribute routines */
 H5_DLL struct H5O_loc_t *H5A_oloc(H5A_t *attr);
 H5_DLL H5G_name_t *H5A_nameof(H5A_t *attr);
+H5_DLL H5T_t *H5A_type(const H5A_t *attr);
+H5_DLL herr_t H5O_attr_iterate_real(hid_t loc_id, const H5O_loc_t *loc,
+    hid_t dxpl_id, H5_index_t idx_type, H5_iter_order_t order, hsize_t skip,
+    hsize_t *last_attr, const H5A_attr_iter_op_t *attr_op, void *op_data);
+H5_DLL herr_t H5O_attr_iterate(hid_t loc_id, hid_t dxpl_id, H5_index_t idx_type,
+    H5_iter_order_t order, hsize_t skip, hsize_t *last_attr,
+    const H5A_attr_iter_op_t *op, void *op_data);
 
 #endif /* _H5Aprivate_H */
 
diff --git a/src/H5Bcache.c b/src/H5Bcache.c
index c0fd121..68fb920 100644
--- a/src/H5Bcache.c
+++ b/src/H5Bcache.c
@@ -152,6 +152,10 @@ H5B_load(H5F_t *f, hid_t dxpl_id, haddr_t addr, void *_udata)
     /* entries used */
     UINT16DECODE(p, bt->nchildren);
 
+    /* Check if bt->nchildren is greater than two_k */
+    if(bt->nchildren > shared->two_k)
+        HGOTO_ERROR(H5E_BTREE, H5E_BADVALUE, NULL, "number of children is greater than maximum")
+
     /* sibling pointers */
     H5F_addr_decode(udata->f, (const uint8_t **)&p, &(bt->left));
     H5F_addr_decode(udata->f, (const uint8_t **)&p, &(bt->right));
diff --git a/src/H5Dchunk.c b/src/H5Dchunk.c
index 46925a1..af888a9 100644
--- a/src/H5Dchunk.c
+++ b/src/H5Dchunk.c
@@ -974,7 +974,7 @@ H5D_free_chunk_info(void *item, void UNUSED *key, void UNUSED *opdata)
         H5S_select_all(chunk_info->fspace, TRUE);
 
     /* Close the chunk's memory dataspace, if it's not shared */
-    if(!chunk_info->mspace_shared)
+    if(!chunk_info->mspace_shared && chunk_info->mspace)
         (void)H5S_close(chunk_info->mspace);
 
     /* Free the actual chunk info */
diff --git a/src/H5Dcontig.c b/src/H5Dcontig.c
index 674582d..c1ff68c 100644
--- a/src/H5Dcontig.c
+++ b/src/H5Dcontig.c
@@ -420,6 +420,7 @@ H5D_contig_construct(H5F_t *f, H5D_t *dset)
     hsize_t nelmts;                     /* Number of elements in dataspace */
     size_t dt_size;                     /* Size of datatype */
     hsize_t tmp_size;                   /* Temporary holder for raw data size */
+    size_t tmp_sieve_buf_size;          /* Temporary holder for sieve buffer size */
     hsize_t dim[H5O_LAYOUT_NDIMS];	/* Current size of data in elements */
     hsize_t max_dim[H5O_LAYOUT_NDIMS];  /* Maximum size of data in elements */
     int ndims;                          /* Rank of dataspace */
@@ -464,8 +465,15 @@ H5D_contig_construct(H5F_t *f, H5D_t *dset)
     /* Assign the dataset's contiguous storage size */
     dset->shared->layout.storage.u.contig.size = tmp_size;
 
-    /* Get the sieve buffer size for this dataset */
-    dset->shared->cache.contig.sieve_buf_size = H5F_SIEVE_BUF_SIZE(f);
+    /* Get the sieve buffer size for the file */
+    tmp_sieve_buf_size = H5F_SIEVE_BUF_SIZE(f);
+
+    /* Adjust the sieve buffer size to the smaller one between the dataset size and the buffer size
+     * from the file access property. (SLU - 2012/3/30) */
+    if(tmp_size < tmp_sieve_buf_size)
+        dset->shared->cache.contig.sieve_buf_size = tmp_size;
+    else
+        dset->shared->cache.contig.sieve_buf_size = tmp_sieve_buf_size;
 
 done:
     FUNC_LEAVE_NOAPI(ret_value)
@@ -965,6 +973,7 @@ H5D_contig_writevv_sieve_cb(hsize_t dst_off, hsize_t src_off, size_t len,
             /* Allocate room for the data sieve buffer */
             if(NULL == (dset_contig->sieve_buf = H5FL_BLK_MALLOC(sieve_buf, dset_contig->sieve_buf_size)))
                 HGOTO_ERROR(H5E_DATASET, H5E_CANTALLOC, FAIL, "memory allocation failed")
+
 #ifdef H5_CLEAR_MEMORY
 if(dset_contig->sieve_size > len)
     HDmemset(dset_contig->sieve_buf + len, 0, (dset_contig->sieve_size - len));
diff --git a/src/H5Dint.c b/src/H5Dint.c
index 31cd84b..e17c0f7 100644
--- a/src/H5Dint.c
+++ b/src/H5Dint.c
@@ -68,7 +68,6 @@ static herr_t H5D_init_space(H5F_t *file, const H5D_t *dset, const H5S_t *space)
 static herr_t H5D_update_oh_info(H5F_t *file, hid_t dxpl_id, H5D_t *dset,
     hid_t dapl_id);
 static herr_t H5D_open_oid(H5D_t *dataset, hid_t dapl_id, hid_t dxpl_id);
-static herr_t H5D_flush_real(H5D_t *dataset, hid_t dxpl_id);
 
 
 /*********************/
@@ -2440,7 +2439,8 @@ H5D_flush(const H5F_t *f, hid_t dxpl_id)
     udata.dxpl_id = dxpl_id;
 
     /* Iterate over all the open datasets */
-    H5I_search(H5I_DATASET, H5D_flush_cb, &udata, FALSE);
+    if(H5I_iterate(H5I_DATASET, H5D_flush_cb, &udata, FALSE) < 0)
+        HGOTO_ERROR(H5E_DATASET, H5E_BADITER, FAIL, "unable to flush cached dataset info")
 
 done:
     FUNC_LEAVE_NOAPI(ret_value)
diff --git a/src/H5Dio.c b/src/H5Dio.c
index 49a8f25..7a58c4a 100644
--- a/src/H5Dio.c
+++ b/src/H5Dio.c
@@ -362,6 +362,7 @@ H5D_read(H5D_t *dataset, hid_t mem_type_id, const H5S_t *mem_space,
                 || dataset->shared->layout.type == H5D_COMPACT);
 
     /* Call storage method's I/O initialization routine */
+    HDmemset(&fm, 0, sizeof(H5D_chunk_map_t));
     if(io_info.layout_ops.io_init && (*io_info.layout_ops.io_init)(&io_info, &type_info, nelmts, file_space, mem_space, &fm) < 0)
         HGOTO_ERROR(H5E_DATASET, H5E_CANTINIT, FAIL, "can't initialize I/O info")
     io_op_init = TRUE;
@@ -585,6 +586,7 @@ H5D_write(H5D_t *dataset, hid_t mem_type_id, const H5S_t *mem_space,
 #endif /*H5_HAVE_PARALLEL*/
 
     /* Call storage method's I/O initialization routine */
+    HDmemset(&fm, 0, sizeof(H5D_chunk_map_t));
     if(io_info.layout_ops.io_init && (*io_info.layout_ops.io_init)(&io_info, &type_info, nelmts, file_space, mem_space, &fm) < 0)
         HGOTO_ERROR(H5E_DATASET, H5E_CANTINIT, FAIL, "can't initialize I/O info")
     io_op_init = TRUE;
diff --git a/src/H5Dlayout.c b/src/H5Dlayout.c
index 7ec6404..53d49aa 100644
--- a/src/H5Dlayout.c
+++ b/src/H5Dlayout.c
@@ -384,6 +384,10 @@ H5D_layout_oh_read(H5D_t *dataset, hid_t dxpl_id, hid_t dapl_id, H5P_genplist_t
 
     switch(dataset->shared->layout.type) {
         case H5D_CONTIGUOUS:
+        {
+            hsize_t tmp_size;                   /* Temporary holder for raw data size */
+            size_t tmp_sieve_buf_size;          /* Temporary holder for sieve buffer size */
+
             /* Compute the size of the contiguous storage for versions of the
              * layout message less than version 3 because versions 1 & 2 would
              * truncate the dimension sizes to 32-bits of information. - QAK 5/26/04
@@ -392,7 +396,6 @@ H5D_layout_oh_read(H5D_t *dataset, hid_t dxpl_id, hid_t dapl_id, H5P_genplist_t
                 hssize_t snelmts;                   /* Temporary holder for number of elements in dataspace */
                 hsize_t nelmts;                     /* Number of elements in dataspace */
                 size_t dt_size;                     /* Size of datatype */
-                hsize_t tmp_size;                   /* Temporary holder for raw data size */
 
                 /* Retrieve the number of elements in the dataspace */
                 if((snelmts = H5S_GET_EXTENT_NPOINTS(dataset->shared->space)) < 0)
@@ -412,10 +415,19 @@ H5D_layout_oh_read(H5D_t *dataset, hid_t dxpl_id, hid_t dapl_id, H5P_genplist_t
 
                 /* Assign the dataset's contiguous storage size */
                 dataset->shared->layout.storage.u.contig.size = tmp_size;
-            } /* end if */
-
-            /* Get the sieve buffer size for this dataset */
-            dataset->shared->cache.contig.sieve_buf_size = H5F_SIEVE_BUF_SIZE(dataset->oloc.file);
+            } else
+                tmp_size = dataset->shared->layout.storage.u.contig.size;
+
+	    /* Get the sieve buffer size for the file */
+	    tmp_sieve_buf_size = H5F_SIEVE_BUF_SIZE(dataset->oloc.file);
+
+	    /* Adjust the sieve buffer size to the smaller one between the dataset size and the buffer size
+	     * from the file access property.  (SLU - 2012/3/30) */
+	    if(tmp_size < tmp_sieve_buf_size)
+		dataset->shared->cache.contig.sieve_buf_size = tmp_size;
+	    else
+		dataset->shared->cache.contig.sieve_buf_size = tmp_sieve_buf_size;
+        }
             break;
 
         case H5D_CHUNKED:
diff --git a/src/H5Doh.c b/src/H5Doh.c
index 7a657ec..e6a715f 100644
--- a/src/H5Doh.c
+++ b/src/H5Doh.c
@@ -56,6 +56,8 @@ static H5O_loc_t *H5O_dset_get_oloc(hid_t obj_id);
 static herr_t H5O_dset_bh_info(H5F_t *f, hid_t dxpl_id, H5O_t *oh,
     H5_ih_info_t *bh_info);
 
+static herr_t H5O_dset_flush(H5G_loc_t *obj_loc, hid_t dxpl_id);
+
 
 /*********************/
 /* Package Variables */
@@ -81,7 +83,8 @@ const H5O_obj_class_t H5O_OBJ_DATASET[1] = {{
     H5O_dset_open, 		/* open an object of this class */
     H5O_dset_create, 		/* create an object of this class */
     H5O_dset_get_oloc, 		/* get an object header location for an object */
-    H5O_dset_bh_info 		/* get the index & heap info for an object */
+    H5O_dset_bh_info, 		/* get the index & heap info for an object */
+    H5O_dset_flush 		/* flush an opened object of this class */
 }};
 
 /* Declare a free list to manage the H5D_copy_file_ud_t struct */
@@ -431,3 +434,48 @@ done:
     FUNC_LEAVE_NOAPI(ret_value)
 } /* end H5O_dset_bh_info() */
 
+
+/*-------------------------------------------------------------------------
+ * Function:    H5O_dset_flush
+ *
+ * Purpose:     To flush any dataset information cached in memory
+ *
+ * Return:      Success:        non-negative
+ *              Failure:        negative
+ *
+ * Programmer:  Vailin Choi
+ *              February 2012
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+H5O_dset_flush(H5G_loc_t *obj_loc, hid_t dxpl_id)
+{
+    H5D_t       *dset;                  /* Dataset opened */
+    H5O_type_t 	obj_type;              /* Type of object at location */
+    herr_t      ret_value = SUCCEED;    /* Return value */
+
+    FUNC_ENTER_NOAPI_NOINIT
+
+    HDassert(obj_loc);
+    HDassert(obj_loc->oloc);
+
+    /* Check that the object found is the correct type */
+    if(H5O_obj_type(obj_loc->oloc, &obj_type, dxpl_id) < 0)
+        HGOTO_ERROR(H5E_DATASET, H5E_CANTGET, FAIL, "can't get object type")
+
+    if(obj_type != H5O_TYPE_DATASET)
+        HGOTO_ERROR(H5E_DATASET, H5E_BADTYPE, FAIL, "not a dataset")
+
+    /* Open the dataset */
+    if(NULL == (dset = H5D_open(obj_loc, H5P_DATASET_ACCESS_DEFAULT, dxpl_id)))
+        HGOTO_ERROR(H5E_DATASET, H5E_CANTOPENOBJ, FAIL, "unable to open dataset")
+    
+    if(H5D_flush_real(dset, dxpl_id) < 0)
+	HDONE_ERROR(H5E_DATASET, H5E_WRITEERROR, FAIL, "unable to flush cached dataset info")
+
+done:
+    if(dset && H5D_close(dset) < 0)
+	HDONE_ERROR(H5E_DATASET, H5E_CLOSEERROR, NULL, "unable to release dataset")
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5O_dset_flush() */
diff --git a/src/H5Dpkg.h b/src/H5Dpkg.h
index 16de07f..40317f3 100644
--- a/src/H5Dpkg.h
+++ b/src/H5Dpkg.h
@@ -548,6 +548,7 @@ H5_DLL herr_t H5D_set_extent(H5D_t *dataset, const hsize_t *size, hid_t dxpl_id)
 H5_DLL herr_t H5D_get_dxpl_cache(hid_t dxpl_id, H5D_dxpl_cache_t **cache);
 H5_DLL herr_t H5D_flush_sieve_buf(H5D_t *dataset, hid_t dxpl_id);
 H5_DLL herr_t H5D_mark(H5D_t *dataset, hid_t dxpl_id, unsigned flags);
+H5_DLL herr_t H5D_flush_real(H5D_t *dataset, hid_t dxpl_id);
 
 /* Functions that perform direct serial I/O operations */
 H5_DLL herr_t H5D_select_read(const H5D_io_info_t *io_info,
diff --git a/src/H5E.c b/src/H5E.c
index 4e14887..e74211e 100644
--- a/src/H5E.c
+++ b/src/H5E.c
@@ -107,7 +107,7 @@ static H5E_cls_t *H5E_register_class(const char *cls_name, const char *lib_name,
                                 const char *version);
 static herr_t  H5E_unregister_class(H5E_cls_t *cls);
 static ssize_t H5E_get_class_name(const H5E_cls_t *cls, char *name, size_t size);
-static int H5E_close_msg_cb(void *obj_ptr, hid_t obj_id, void *key);
+static int H5E_close_msg_cb(void *obj_ptr, hid_t obj_id, void *udata);
 static herr_t  H5E_close_msg(H5E_msg_t *err);
 static H5E_msg_t *H5E_create_msg(H5E_cls_t *cls, H5E_type_t msg_type, const char *msg);
 static H5E_t  *H5E_get_current_stack(void);
@@ -543,8 +543,8 @@ H5E_unregister_class(H5E_cls_t *cls)
     HDassert(cls);
 
     /* Iterate over all the messages and delete those in this error class */
-    /* (Ignore return value, since callback isn't designed to return a particular object) */
-    (void)H5I_search(H5I_ERROR_MSG, H5E_close_msg_cb, cls, FALSE);
+    if(H5I_iterate(H5I_ERROR_MSG, H5E_close_msg_cb, cls, FALSE) < 0)
+        HGOTO_ERROR(H5E_ERROR, H5E_BADITER, FAIL, "unable to free all messages in this error class")
 
     /* Free error class structure */
     if(H5E_free_class(cls) < 0)
@@ -631,7 +631,7 @@ H5E_get_class_name(const H5E_cls_t *cls, char *name, size_t size)
 /*-------------------------------------------------------------------------
  * Function:    H5E_close_msg_cb
  *
- * Purpose:     H5I_search callback function to close error messages in the
+ * Purpose:     H5I_iterate callback function to close error messages in the
  *              error class.
  *
  * Return:	Non-negative value on success/Negative on failure
@@ -642,10 +642,10 @@ H5E_get_class_name(const H5E_cls_t *cls, char *name, size_t size)
  *-------------------------------------------------------------------------
  */
 static int
-H5E_close_msg_cb(void *obj_ptr, hid_t obj_id, void *key)
+H5E_close_msg_cb(void *obj_ptr, hid_t obj_id, void *udata)
 {
     H5E_msg_t   *err_msg = (H5E_msg_t*)obj_ptr;
-    H5E_cls_t   *cls = (H5E_cls_t*)key;
+    H5E_cls_t   *cls = (H5E_cls_t*)udata;
     herr_t      ret_value = SUCCEED;       /* Return value */
 
     FUNC_ENTER_NOAPI_NOINIT
diff --git a/src/H5Edefin.h b/src/H5Edefin.h
index 7fa8b12..27275a3 100644
--- a/src/H5Edefin.h
+++ b/src/H5Edefin.h
@@ -94,6 +94,7 @@ hid_t H5E_CANTRELEASE_g    = FAIL;      /* Unable to release object */
 hid_t H5E_CANTGET_g        = FAIL;      /* Can't get value */
 hid_t H5E_CANTSET_g        = FAIL;      /* Can't set value */
 hid_t H5E_DUPCLASS_g       = FAIL;      /* Duplicate class name in parent class */
+hid_t H5E_SETDISALLOWED_g  = FAIL;      /* Disallowed operation */
 
 /* Free space errors */
 hid_t H5E_CANTMERGE_g      = FAIL;      /* Can't merge objects */
diff --git a/src/H5Einit.h b/src/H5Einit.h
index 7022297..99467ee 100644
--- a/src/H5Einit.h
+++ b/src/H5Einit.h
@@ -344,6 +344,11 @@ if((msg = H5E_create_msg(cls, H5E_MINOR, "Duplicate class name in parent class")
     HGOTO_ERROR(H5E_ERROR, H5E_CANTINIT, FAIL, "error message initialization failed")
 if((H5E_DUPCLASS_g = H5I_register(H5I_ERROR_MSG, msg, FALSE))<0)
     HGOTO_ERROR(H5E_ERROR, H5E_CANTREGISTER, FAIL, "can't register error message")
+assert(H5E_SETDISALLOWED_g==(-1));
+if((msg = H5E_create_msg(cls, H5E_MINOR, "Disallowed operation"))==NULL)
+    HGOTO_ERROR(H5E_ERROR, H5E_CANTINIT, FAIL, "error message initialization failed")
+if((H5E_SETDISALLOWED_g = H5I_register(H5I_ERROR_MSG, msg, FALSE))<0)
+    HGOTO_ERROR(H5E_ERROR, H5E_CANTREGISTER, FAIL, "can't register error message")
 
 /* Free space errors */
 assert(H5E_CANTMERGE_g==(-1));
diff --git a/src/H5Epubgen.h b/src/H5Epubgen.h
index 12771b2..68c605c 100644
--- a/src/H5Epubgen.h
+++ b/src/H5Epubgen.h
@@ -157,9 +157,11 @@ H5_DLLVAR hid_t H5E_CANTRELEASE_g;   /* Unable to release object */
 #define H5E_CANTGET          (H5OPEN H5E_CANTGET_g)
 #define H5E_CANTSET          (H5OPEN H5E_CANTSET_g)
 #define H5E_DUPCLASS         (H5OPEN H5E_DUPCLASS_g)
+#define H5E_SETDISALLOWED    (H5OPEN H5E_SETDISALLOWED_g)
 H5_DLLVAR hid_t H5E_CANTGET_g;       /* Can't get value */
 H5_DLLVAR hid_t H5E_CANTSET_g;       /* Can't set value */
 H5_DLLVAR hid_t H5E_DUPCLASS_g;      /* Duplicate class name in parent class */
+H5_DLLVAR hid_t H5E_SETDISALLOWED_g; /* Disallowed operation */
 
 /* Free space errors */
 #define H5E_CANTMERGE        (H5OPEN H5E_CANTMERGE_g)
diff --git a/src/H5Eterm.h b/src/H5Eterm.h
index 1860c19..28d822a 100644
--- a/src/H5Eterm.h
+++ b/src/H5Eterm.h
@@ -95,7 +95,8 @@ H5E_CANTRELEASE_g=
 /* Property list errors */    
 H5E_CANTGET_g=    
 H5E_CANTSET_g=    
-H5E_DUPCLASS_g=
+H5E_DUPCLASS_g=    
+H5E_SETDISALLOWED_g=
 
 /* Free space errors */    
 H5E_CANTMERGE_g=    
diff --git a/src/H5F.c b/src/H5F.c
index 7c7db13..93d7cc6 100644
--- a/src/H5F.c
+++ b/src/H5F.c
@@ -53,7 +53,7 @@ typedef struct H5F_olist_t {
 } H5F_olist_t;
 
 /* PRIVATE PROTOTYPES */
-static size_t H5F_get_objects(const H5F_t *f, unsigned types, size_t max_objs, hid_t *obj_id_list, hbool_t app_ref);
+static herr_t H5F_get_objects(const H5F_t *f, unsigned types, size_t max_index, hid_t *obj_id_list, hbool_t app_ref, size_t *obj_id_count_ptr);
 static int H5F_get_objects_cb(void *obj_ptr, hid_t obj_id, void *key);
 static H5F_t *H5F_new(H5F_file_t *shared, hid_t fcpl_id, hid_t fapl_id,
                       H5FD_t *lf);
@@ -353,42 +353,38 @@ done:
  *
  * Programmer:	Raymond Lu
  *		Wednesday, Dec 5, 2001
- * Modification:
- *              Raymond Lu
- *              24 September 2008
- *              Changed the return value to ssize_t to  accommadate
- *              potential large number of objects.
  *
  *-------------------------------------------------------------------------
  */
 ssize_t
-H5Fget_obj_count(hid_t uid, unsigned types)
+H5Fget_obj_count(hid_t file_id, unsigned types)
 {
-    H5F_t    *f = NULL;         /* File to query */
-    H5VL_id_wrapper_t    *id_wrapper;         /* user id structure */
-    hid_t    id;
-    ssize_t  ret_value;         /* Return value */
+    H5F_t   *f = NULL;         /* File to query */
+    ssize_t ret_value;         /* Return value */
+    size_t  obj_count = 0;      /* Number of opened objects */
 
     FUNC_ENTER_API(FAIL)
-    H5TRACE2("Zs", "iIu", uid, types);
+    H5TRACE2("Zs", "iIu", file_id, types);
 
-    if (H5I_FILE_PUBLIC == H5I_get_type(uid)) {
-        if(NULL == (id_wrapper = (H5VL_id_wrapper_t *)H5I_object(uid)))
+    if (H5I_FILE_PUBLIC == H5I_get_type(file_id)) {
+        H5VL_id_wrapper_t    *id_wrapper;    /* wrapper object */
+
+        if(NULL == (id_wrapper = (H5VL_id_wrapper_t *)H5I_object(file_id)))
             HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "invalid user identifier")
-        id = id_wrapper->obj_id;
-    }
-    else {
-        id = uid;
+        file_id = id_wrapper->obj_id;
     }
 
-    if(id != (hid_t)H5F_OBJ_ALL && 
-       (NULL == (f = (H5F_t *)H5I_object_verify(id, H5I_FILE))))
+    if(file_id != (hid_t)H5F_OBJ_ALL && (NULL == (f = (H5F_t *)H5I_object_verify(file_id, H5I_FILE))))
         HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "not a file id")
     if(0 == (types & H5F_OBJ_ALL))
         HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "not an object type")
 
-    /* H5F_get_obj_count doesn't fail */
-    ret_value = (ssize_t)H5F_get_obj_count(f, types, TRUE);
+    /* Perform the query */
+    if(H5F_get_obj_count(f, types, TRUE, &obj_count) < 0)
+	HGOTO_ERROR(H5E_INTERNAL, H5E_BADITER, FAIL, "H5F_get_obj_count failed")
+
+    /* Set the return value */
+    ret_value = (ssize_t)obj_count;
 
 done:
     FUNC_LEAVE_API(ret_value)
@@ -401,31 +397,30 @@ done:
  * Purpose:	Private function return the number of opened object IDs
  *		(files, datasets, groups, datatypes) in the same file.
  *
- * Return:      Non-negative on success; can't fail.
+ * Return:      SUCCEED on success, FAIL on failure.
  *
  * Programmer:  Raymond Lu
  *              Wednesday, Dec 5, 2001
  *
- * Modification:
- *              Raymond Lu
- *              24 September 2008
- *              Changed the return value to size_t to accommadate
- *              potential large number of objects.
- *
  *-------------------------------------------------------------------------
  */
-size_t
-H5F_get_obj_count(const H5F_t *f, unsigned types, hbool_t app_ref)
+herr_t
+H5F_get_obj_count(const H5F_t *f, unsigned types, hbool_t app_ref, size_t *obj_id_count_ptr)
 {
-    size_t   ret_value;            /* Return value */
+    herr_t   ret_value = SUCCEED;
 
-    FUNC_ENTER_NOAPI_NOINIT_NOERR
+    FUNC_ENTER_NOAPI(FAIL)
 
-    /* H5F_get_objects doesn't fail */
-    ret_value = H5F_get_objects(f, types, 0, NULL, app_ref);
+    /* Sanity check */
+    HDassert(obj_id_count_ptr);
+
+    /* Perform the query */
+    if((ret_value = H5F_get_objects(f, types, 0, NULL, app_ref, obj_id_count_ptr)) < 0)
+        HGOTO_ERROR(H5E_INTERNAL, H5E_BADITER, FAIL, "H5F_get_objects failed")
 
+done:
     FUNC_LEAVE_NOAPI(ret_value)
-}
+} /* end H5F_get_obj_count() */
 
 
 /*-------------------------------------------------------------------------
@@ -447,34 +442,36 @@ H5F_get_obj_count(const H5F_t *f, unsigned types, hbool_t app_ref)
  *-------------------------------------------------------------------------
  */
 ssize_t
-H5Fget_obj_ids(hid_t uid, unsigned types, size_t max_objs, hid_t *oid_list)
+H5Fget_obj_ids(hid_t file_id, unsigned types, size_t max_objs, hid_t *oid_list)
 {
     H5F_t     *f = NULL;        /* File to query */
-    H5VL_id_wrapper_t     *id_wrapper;        /* user id structure */
-    hid_t     id;
+    size_t    obj_id_count = 0; /* Number of open objects */
     ssize_t   ret_value;        /* Return value */
 
     FUNC_ENTER_API(FAIL)
-    H5TRACE4("Zs", "iIuz*i", uid, types, max_objs, oid_list);
+    H5TRACE4("Zs", "iIuz*i", file_id, types, max_objs, oid_list);
 
-    if (H5I_FILE_PUBLIC == H5I_get_type(uid)) {
-        if(NULL == (id_wrapper = (H5VL_id_wrapper_t *)H5I_object(uid)))
+    if (H5I_FILE_PUBLIC == H5I_get_type(file_id)) {
+        H5VL_id_wrapper_t     *id_wrapper;        /* wrapper object */
+
+        if(NULL == (id_wrapper = (H5VL_id_wrapper_t *)H5I_object(file_id)))
             HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "invalid user identifier")
-        id = id_wrapper->obj_id;
-    }
-    else {
-        id = uid;
+        file_id = id_wrapper->obj_id;
     }
 
-    if(id != (hid_t)H5F_OBJ_ALL && 
-       (NULL == (f = (H5F_t *)H5I_object_verify(id, H5I_FILE))))
+    /* Check arguments */
+    if(file_id != (hid_t)H5F_OBJ_ALL && (NULL == (f = (H5F_t *)H5I_object_verify(file_id, H5I_FILE))))
         HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "not a file id")
     if(0 == (types & H5F_OBJ_ALL))
         HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "not an object type")
     HDassert(oid_list);
 
-    /* H5F_get_objects doesn't fail */
-    ret_value = (ssize_t)H5F_get_obj_ids(f, types, max_objs, oid_list, TRUE);
+    /* Perform the query */
+    if(H5F_get_obj_ids(f, types, max_objs, oid_list, TRUE, &obj_id_count) < 0)
+        HGOTO_ERROR(H5E_INTERNAL, H5E_BADITER, FAIL, "H5F_get_obj_ids failed")
+
+    /* Set the return value */
+    ret_value = (ssize_t)obj_id_count;
 
     if (H5VL_replace_with_uids (oid_list, ret_value) <= 0)
         HGOTO_ERROR(H5E_ATOM, H5E_CANTGET, FAIL, "can't get IDs")
@@ -494,26 +491,25 @@ done:
  * Programmer:  Raymond Lu
  *              Wednesday, Dec 5, 2001
  *
- * Modification:
- *              Raymond Lu
- *              24 September 2008
- *              Changed the return value and MAX_OBJTS to size_t to accommadate
- *              potential large number of objects.
- *
  *-------------------------------------------------------------------------
  */
-size_t
-H5F_get_obj_ids(const H5F_t *f, unsigned types, size_t max_objs, hid_t *oid_list, hbool_t app_ref)
+herr_t
+H5F_get_obj_ids(const H5F_t *f, unsigned types, size_t max_objs, hid_t *oid_list, hbool_t app_ref, size_t *obj_id_count_ptr)
 {
-    size_t ret_value;              /* Return value */
+    herr_t ret_value = SUCCEED;              /* Return value */
 
-    FUNC_ENTER_NOAPI_NOINIT_NOERR
+    FUNC_ENTER_NOAPI(FAIL)
 
-    /* H5F_get_objects doesn't fail */
-    ret_value = H5F_get_objects(f, types, max_objs, oid_list, app_ref);
+    /* Sanity check */
+    HDassert(obj_id_count_ptr);
+
+    /* Perform the query */
+    if((ret_value = H5F_get_objects(f, types, max_objs, oid_list, app_ref, obj_id_count_ptr)) < 0)
+        HGOTO_ERROR(H5E_INTERNAL, H5E_BADITER, FAIL, "H5F_get_objects failed")
 
+done:
     FUNC_LEAVE_NOAPI(ret_value)
-}
+} /* end H5F_get_obj_ids() */
 
 
 /*---------------------------------------------------------------------------
@@ -529,14 +525,18 @@ H5F_get_obj_ids(const H5F_t *f, unsigned types, size_t max_objs, hid_t *oid_list
  *
  *---------------------------------------------------------------------------
  */
-static size_t
-H5F_get_objects(const H5F_t *f, unsigned types, size_t max_index, hid_t *obj_id_list, hbool_t app_ref)
+static herr_t
+H5F_get_objects(const H5F_t *f, unsigned types, size_t max_index, hid_t *obj_id_list, hbool_t app_ref, size_t *obj_id_count_ptr)
 {
     size_t obj_id_count=0;      /* Number of open IDs */
     H5F_olist_t olist;          /* Structure to hold search results */
-    size_t ret_value;          /* Return value */
+    htri_t type_exists;         /* Whether objects of a type are open */
+    herr_t ret_value = SUCCEED; /* Return value */
 
-    FUNC_ENTER_NOAPI_NOINIT_NOERR
+    FUNC_ENTER_NOAPI_NOINIT
+
+    /* Sanity check */
+    HDassert(obj_id_count_ptr);
 
     /* Set up search information */
     olist.obj_id_list  = (max_index==0 ? NULL : obj_id_list);
@@ -554,45 +554,50 @@ H5F_get_objects(const H5F_t *f, unsigned types, size_t max_index, hid_t *obj_id_
         olist.file_info.ptr.shared = f ? f->shared : NULL;
     } /* end else */
 
-    /* Search through file IDs to count the number, and put their
-     * IDs on the object list.  H5I_search returns NULL if no object
-     * is found, so don't return failure in this function. */
+    /* Iterate through file IDs to count the number, and put their
+     * IDs on the object list.  */
     if(types & H5F_OBJ_FILE) {
         olist.obj_type = H5I_FILE;
-        (void)H5I_search(H5I_FILE, H5F_get_objects_cb, &olist, app_ref);
+        if(H5I_iterate(H5I_FILE, H5F_get_objects_cb, &olist, app_ref) < 0)
+            HGOTO_ERROR(H5E_FILE, H5E_BADITER, FAIL, "iteration failed(1)")
     } /* end if */
 
     /* Search through dataset IDs to count number of datasets, and put their
      * IDs on the object list */
     if(types & H5F_OBJ_DATASET) {
         olist.obj_type = H5I_DATASET;
-        (void)H5I_search(H5I_DATASET, H5F_get_objects_cb, &olist, app_ref);
-    }
+        if(H5I_iterate(H5I_DATASET, H5F_get_objects_cb, &olist, app_ref) < 0)
+            HGOTO_ERROR(H5E_FILE, H5E_BADITER, FAIL, "iteration failed(2)")
+    } /* end if */
 
     /* Search through group IDs to count number of groups, and put their
      * IDs on the object list */
     if(types & H5F_OBJ_GROUP) {
         olist.obj_type = H5I_GROUP;
-        (void)H5I_search(H5I_GROUP, H5F_get_objects_cb, &olist, app_ref);
-    }
+        if(H5I_iterate(H5I_GROUP, H5F_get_objects_cb, &olist, app_ref) < 0)
+            HGOTO_ERROR(H5E_FILE, H5E_BADITER, FAIL, "iteration failed(3)")
+    } /* end if */
 
     /* Search through datatype IDs to count number of named datatypes, and put their
      * IDs on the object list */
     if(types & H5F_OBJ_DATATYPE) {
         olist.obj_type = H5I_DATATYPE;
-        (void)H5I_search(H5I_DATATYPE, H5F_get_objects_cb, &olist, app_ref);
-    }
+        if(H5I_iterate(H5I_DATATYPE, H5F_get_objects_cb, &olist, app_ref) < 0)
+            HGOTO_ERROR(H5E_FILE, H5E_BADITER, FAIL, "iteration failed(4)")
+    } /* end if */
 
     /* Search through attribute IDs to count number of attributes, and put their
      * IDs on the object list */
     if(types & H5F_OBJ_ATTR) {
         olist.obj_type = H5I_ATTR;
-        (void)H5I_search(H5I_ATTR, H5F_get_objects_cb, &olist, app_ref);
-    }
+        if(H5I_iterate(H5I_ATTR, H5F_get_objects_cb, &olist, app_ref) < 0)
+            HGOTO_ERROR(H5E_FILE, H5E_BADITER, FAIL, "iteration failed(5)")
+    } /* end if */
 
     /* Set the number of objects currently open */
-    ret_value = obj_id_count;
+    *obj_id_count_ptr = obj_id_count;
 
+done:
     FUNC_LEAVE_NOAPI(ret_value)
 } /* end H5F_get_objects() */
 
@@ -610,8 +615,6 @@ H5F_get_objects(const H5F_t *f, unsigned types, size_t max_index, hid_t *obj_id_
  * Programmer:  Raymond Lu
  *              Wednesday, Dec 5, 2001
  *
- * Modification:
- *
  *-------------------------------------------------------------------------
  */
 static int
@@ -643,8 +646,8 @@ H5F_get_objects_cb(void *obj_ptr, hid_t obj_id, void *key)
 
             /* Check if we've filled up the array.  Return TRUE only if
              * we have filled up the array. Otherwise return FALSE(RET_VALUE is
-             * preset to FALSE) because H5I_search needs the return value of FALSE
-             * to continue searching. */
+             * preset to FALSE) because H5I_iterate needs the return value of 
+ 	     * FALSE to continue the iteration. */
             if(olist->max_index>0 && olist->list_index>=olist->max_index)
                 HGOTO_DONE(TRUE)  /* Indicate that the iterator should stop */
 	}
@@ -709,8 +712,8 @@ H5F_get_objects_cb(void *obj_ptr, hid_t obj_id, void *key)
 
             /* Check if we've filled up the array.  Return TRUE only if
              * we have filled up the array. Otherwise return FALSE(RET_VALUE is
-             * preset to FALSE) because H5I_search needs the return value of FALSE
-             * to continue searching. */
+             * preset to FALSE) because H5I_iterate needs the return value of 
+	     * FALSE to continue iterating. */
             if(olist->max_index>0 && olist->list_index>=olist->max_index)
                 HGOTO_DONE(TRUE)  /* Indicate that the iterator should stop */
     	} /* end if */
@@ -1679,8 +1682,6 @@ done:
  * Programmer:	Quincey Koziol
  *		Tuesday, July 19, 2005
  *
- * Modifications:
- *
  *-------------------------------------------------------------------------
  */
 herr_t
@@ -1762,27 +1763,36 @@ H5F_try_close(H5F_t *f)
         if(f->nopen_objs > 0) {
             size_t obj_count;       /* # of open objects */
             hid_t objs[128];        /* Array of objects to close */
+            herr_t result;          /* Local result from obj ID query */
             size_t u;               /* Local index variable */
 
             /* Get the list of IDs of open dataset, group, & attribute objects */
-            while((obj_count = H5F_get_obj_ids(f, H5F_OBJ_LOCAL|H5F_OBJ_DATASET|H5F_OBJ_GROUP|H5F_OBJ_ATTR, (int)(sizeof(objs)/sizeof(objs[0])), objs, FALSE)) != 0) {
+            while((result = H5F_get_obj_ids(f, H5F_OBJ_LOCAL | H5F_OBJ_DATASET | H5F_OBJ_GROUP | H5F_OBJ_ATTR, (int)(sizeof(objs) / sizeof(objs[0])), objs, FALSE, &obj_count)) <= 0
+                    && obj_count != 0 ) {
+
                 /* Try to close all the open objects in this file */
                 for(u = 0; u < obj_count; u++)
                     if(H5I_dec_ref(objs[u]) < 0)
                         HGOTO_ERROR(H5E_ATOM, H5E_CLOSEERROR, FAIL, "can't close object")
             } /* end while */
+            if(result < 0)
+                HGOTO_ERROR(H5E_INTERNAL, H5E_BADITER, FAIL, "H5F_get_obj_ids failed(1)")
 
             /* Get the list of IDs of open named datatype objects */
             /* (Do this separately from the dataset & attribute IDs, because
              * they could be using one of the named datatypes and then the
              * open named datatype ID will get closed twice)
              */
-            while((obj_count = H5F_get_obj_ids(f, H5F_OBJ_LOCAL|H5F_OBJ_DATATYPE, (int)(sizeof(objs)/sizeof(objs[0])), objs, FALSE)) != 0) {
+            while((result = H5F_get_obj_ids(f, H5F_OBJ_LOCAL | H5F_OBJ_DATATYPE, (int)(sizeof(objs) / sizeof(objs[0])), objs, FALSE, &obj_count)) <= 0
+                    && obj_count != 0) {
+
                 /* Try to close all the open objects in this file */
                 for(u = 0; u < obj_count; u++)
                     if(H5I_dec_ref(objs[u]) < 0)
                         HGOTO_ERROR(H5E_ATOM, H5E_CLOSEERROR, FAIL, "can't close object")
             } /* end while */
+            if(result < 0)
+                HGOTO_ERROR(H5E_INTERNAL, H5E_BADITER, FAIL, "H5F_get_obj_ids failed(2)")
         } /* end if */
     } /* end if */
 
@@ -2427,6 +2437,139 @@ done:
 
 
 /*-------------------------------------------------------------------------
+ * Function:    H5Fget_file_image
+ *
+ * Purpose:     If a buffer is provided (via the buf_ptr argument) and is 
+ *		big enough (size in buf_len argument), load *buf_ptr with
+ *		an image of the open file whose ID is provided in the 
+ *		file_id parameter, and return the number of bytes copied
+ *		to the buffer.
+ *
+ *		If the buffer exists, but is too small to contain an image
+ *		of the indicated file, return a negative number.
+ *
+ *		Finally, if no buffer is provided, return the size of the 
+ *		buffer needed.  This value is simply the eoa of the target 
+ *		file.
+ *
+ *		Note that any user block is skipped.
+ *
+ *		Also note that the function may not be used on files 
+ *		opened with either the split/multi file driver or the
+ *		family file driver.
+ *
+ *		In the former case, the sparse address space makes the 
+ *		get file image operation impractical, due to the size of
+ *		the image typically required.
+ *
+ *		In the case of the family file driver, the problem is
+ *		the driver message in the super block, which will prevent
+ *		the image being opened with any driver other than the
+ *		family file driver -- which negates the purpose of the 
+ *		operation.  This can be fixed, but no resources for 
+ *		this now.
+ *
+ * Return:      Success:        Bytes copied / number of bytes needed.
+ *              Failure:        negative value
+ *
+ * Programmer:  John Mainzer
+ *              11/15/11
+ *
+ *-------------------------------------------------------------------------
+ */
+ssize_t
+H5Fget_file_image(hid_t file_id, void *buf_ptr, size_t buf_len)
+{
+    H5F_t      *file;                   /* File object for file ID */
+    H5FD_t     *fd_ptr;                 /* file driver */
+    haddr_t     eoa;                    /* End of file address */
+    ssize_t     ret_value;              /* Return value */
+
+    FUNC_ENTER_API(FAIL)
+    H5TRACE3("Zs", "i*xz", file_id, buf_ptr, buf_len);
+
+    /* Check args */
+    if(NULL == (file = (H5F_t *)H5I_object_verify(file_id, H5I_FILE)))
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "not a file ID")
+    if(!file || !file->shared || !file->shared->lf)
+        HGOTO_ERROR(H5E_FILE, H5E_BADVALUE, FAIL, "file_id yields invalid file pointer")
+    fd_ptr = file->shared->lf;
+    if(!fd_ptr->cls)
+        HGOTO_ERROR(H5E_FILE, H5E_BADVALUE, FAIL, "fd_ptr yields invalid class pointer")
+
+    /* the address space used by the split and multi file drivers is not
+     * a good fit for this call.  Since the plan is to depreciate these
+     * drivers anyway, don't bother to do a "force fit".
+     *
+     * The following clause tests for the multi file driver, and fails
+     * if the supplied file has the multi file driver as its top level
+     * file driver.  However, this test will not work if there is some
+     * other file driver sitting on top of the multi file driver.
+     *
+     * I'm not sure if this is possible at present, but in all likelyhood,
+     * it will become possible in the future.  On the other hand, we may
+     * remove the split/multi file drivers before then.
+     *
+     * I am leaving this solution in for now, but we should review it,
+     * and improve the solution if necessary.
+     *
+     *                                          JRM -- 11/11/22
+     */
+    if(HDstrcmp(fd_ptr->cls->name, "multi") == 0)
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "Not supported for multi file driver.")
+
+    /* While the family file driver is conceptually fully compatible 
+     * with the get file image operation, it sets a file driver message
+     * in the super block that prevents the image being opened with any
+     * driver other than the family file driver.  Needless to say, this
+     * rather defeats the purpose of the get file image operation.
+     *
+     * While this problem is quire solvable, the required time and 
+     * resources are lacking at present.  Hence, for now, we don't
+     * allow the get file image operation to be perfomed on files 
+     * opened with the family file driver.
+     *
+     * Observe that the following test only looks at the top level 
+     * driver, and fails if there is some other driver sitting on to
+     * of the family file driver.  
+     *
+     * I don't think this can happen at present, but that may change
+     * in the future.
+     *                                   JRM -- 12/21/11
+     */
+    if(HDstrcmp(fd_ptr->cls->name, "family") == 0)
+        HGOTO_ERROR(H5E_FILE, H5E_BADVALUE, FAIL, "Not supported for family file driver.")
+
+
+    /* Go get the actual file size */
+    if(HADDR_UNDEF == (eoa = H5FD_get_eoa(file->shared->lf, H5FD_MEM_DEFAULT)))
+        HGOTO_ERROR(H5E_FILE, H5E_CANTGET, FAIL, "unable to get file size")
+
+    /* set ret_value = to eoa -- will overwrite this if appropriate */
+    ret_value = (ssize_t)eoa;
+
+    /* test to see if a buffer was provided -- if not, we are done */
+    if(buf_ptr != NULL) {
+        size_t	space_needed;		/* size of file image */
+
+        /* Check for buffer too small */
+        if((haddr_t)buf_len < eoa)
+            HGOTO_ERROR(H5E_FILE, H5E_BADVALUE, FAIL, "supplied buffer too small")
+
+        space_needed = (size_t)eoa;
+
+        /* read in the file image */
+        /* (Note compensation for base address addition in internal routine) */
+        if(H5FD_read(fd_ptr, H5AC_ind_dxpl_id, H5FD_MEM_DEFAULT, 0, space_needed, buf_ptr) < 0)
+            HGOTO_ERROR(H5E_FILE, H5E_READERROR, FAIL, "file image read request failed")
+    } /* end if */
+    
+done:
+    FUNC_LEAVE_API(ret_value)
+} /* H5Fget_file_image() */
+
+
+/*-------------------------------------------------------------------------
  * Function:    H5Fget_mdc_config
  *
  * Purpose:     Retrieves the current automatic cache resize configuration
diff --git a/src/H5FD.c b/src/H5FD.c
index 66fa3b9..18b0eb6 100644
--- a/src/H5FD.c
+++ b/src/H5FD.c
@@ -70,6 +70,10 @@ static herr_t H5FD_pl_copy(void *(*copy_func)(const void *), size_t pl_size,
 static herr_t H5FD_pl_close(hid_t driver_id, herr_t (*free_func)(void *),
     void *pl);
 static herr_t H5FD_free_cls(H5FD_class_t *cls);
+static herr_t H5FD_fapl_copy(hid_t driver_id, const void *fapl, void **copied_fapl);
+static herr_t H5FD_dxpl_copy(hid_t driver_id, const void *dxpl, void **copied_dxpl);
+static int H5FD_query(const H5FD_t *f, unsigned long *flags/*out*/);
+static int H5FD_driver_query(const H5FD_class_t *driver, unsigned long *flags/*out*/);
 
 /*********************/
 /* Package Variables */
@@ -750,17 +754,15 @@ done:
  * Programmer:	Robb Matzke
  *              Tuesday, August  3, 1999
  *
- * Modifications:
- *
  *-------------------------------------------------------------------------
  */
-herr_t
+static herr_t
 H5FD_fapl_copy(hid_t driver_id, const void *old_fapl, void **copied_fapl)
 {
     H5FD_class_t *driver;
     herr_t ret_value = SUCCEED;       /* Return value */
 
-    FUNC_ENTER_NOAPI(FAIL)
+    FUNC_ENTER_NOAPI_NOINIT
 
     /* Check args */
     if(NULL == (driver = (H5FD_class_t *)H5I_object(driver_id)))
@@ -871,17 +873,15 @@ done:
  * Programmer:	Robb Matzke
  *              Tuesday, August  3, 1999
  *
- * Modifications:
- *
  *-------------------------------------------------------------------------
  */
-herr_t
+static herr_t
 H5FD_dxpl_copy(hid_t driver_id, const void *old_dxpl, void **copied_dxpl)
 {
     H5FD_class_t *driver;
     herr_t ret_value = SUCCEED;       /* Return value */
 
-    FUNC_ENTER_NOAPI(FAIL)
+    FUNC_ENTER_NOAPI_NOINIT
 
     /* Check args */
     if(NULL == (driver = (H5FD_class_t *)H5I_object(driver_id)))
@@ -1039,6 +1039,8 @@ H5FD_open(const char *name, unsigned flags, hid_t fapl_id, haddr_t maxaddr)
     H5FD_t		*file = NULL;           /* VFD file struct */
     hid_t               driver_id = -1;         /* VFD ID */
     H5P_genplist_t      *plist;                 /* Property list pointer */
+    unsigned long       driver_flags = 0;       /* File-inspecific driver feature flags */
+    H5FD_file_image_info_t file_image_info;     /* Initial file image */
     H5FD_t		*ret_value;             /* Return value */
 
     FUNC_ENTER_NOAPI(NULL)
@@ -1061,6 +1063,19 @@ H5FD_open(const char *name, unsigned flags, hid_t fapl_id, haddr_t maxaddr)
     if(NULL == driver->open)
 	HGOTO_ERROR(H5E_VFL, H5E_UNSUPPORTED, NULL, "file driver has no `open' method")
 
+    /* Query driver flag */
+    H5FD_driver_query(driver, &driver_flags);
+
+    /* Get initial file image info */
+    if(H5P_get(plist, H5F_ACS_FILE_IMAGE_INFO_NAME, &file_image_info) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, NULL, "can't get file image info")
+
+    /* If an image is provided, make sure the driver supports this feature */
+    HDassert(((file_image_info.buffer != NULL) && (file_image_info.size > 0)) ||
+             ((file_image_info.buffer == NULL) && (file_image_info.size == 0)));
+    if((file_image_info.buffer != NULL) && !(driver_flags & H5FD_FEAT_ALLOW_FILE_IMAGE))
+        HGOTO_ERROR(H5E_VFL, H5E_UNSUPPORTED, NULL, "file image set, but not supported.")
+
     /* Dispatch to file driver */
     if(HADDR_UNDEF == maxaddr)
         maxaddr = driver->maxaddr;
@@ -1318,19 +1333,17 @@ done:
  * Programmer:	Quincey Koziol
  *              Friday, August 25, 2000
  *
- * Modifications:
- *
  *-------------------------------------------------------------------------
  */
-int
+static int
 H5FD_query(const H5FD_t *f, unsigned long *flags/*out*/)
 {
-    int	ret_value=0;
+    int	ret_value = 0;          /* Return value */
 
-    FUNC_ENTER_NOAPI(FAIL)
+    FUNC_ENTER_NOAPI_NOINIT
 
-    assert(f);
-    assert(flags);
+    HDassert(f);
+    HDassert(flags);
 
     /* Check for query driver and call it */
     if(f->cls->query)
@@ -1340,7 +1353,44 @@ H5FD_query(const H5FD_t *f, unsigned long *flags/*out*/)
 
 done:
     FUNC_LEAVE_NOAPI(ret_value)
-}
+} /* end H5FD_query() */
+
+
+/*-------------------------------------------------------------------------
+* Function:    H5FD_driver_query
+*
+* Purpose: Similar to H5FD_query(), but intended for cases when we don't
+*          have a file available (e.g. before one is opened). Since we
+*          can't use the file to get the driver, the driver is passed in
+*          as a parameter.
+*
+* Return:  Success:    non-negative
+*          Failure:    negative
+*
+* Programmer:  Jacob Gruber
+*              Wednesday, August 17, 2011
+*
+*-------------------------------------------------------------------------
+*/
+static int
+H5FD_driver_query(const H5FD_class_t *driver, unsigned long *flags/*out*/)
+{
+    int ret_value = 0;          /* Return value */
+
+    FUNC_ENTER_NOAPI_NOINIT
+
+    HDassert(driver);
+    HDassert(flags);
+
+    /* Check for the driver to query and then query it */
+    if(driver->query)
+        ret_value = (driver->query)(NULL, flags);
+    else 
+        *flags = 0;
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5FD_driver_query() */
 
 
 /*-------------------------------------------------------------------------
diff --git a/src/H5FDcore.c b/src/H5FDcore.c
index 940d4c7..1fef36c 100644
--- a/src/H5FDcore.c
+++ b/src/H5FDcore.c
@@ -101,6 +101,7 @@ typedef struct H5FD_core_t {
     HANDLE          hFile;      /* Native windows file handle */
 #endif /* H5_HAVE_WIN32_API */
     hbool_t	dirty;			/*changes not saved?		*/
+    H5FD_file_image_callbacks_t fi_callbacks; /* file image callbacks */
 } H5FD_core_t;
 
 /* Driver-specific file access properties */
@@ -412,6 +413,7 @@ H5FD_core_open(const char *name, unsigned flags, hid_t fapl_id,
 #endif
     h5_stat_t		sb;
     int			fd=-1;
+    H5FD_file_image_info_t   file_image_info;
     H5FD_t		*ret_value;
 
     FUNC_ENTER_NOAPI_NOINIT
@@ -434,10 +436,32 @@ H5FD_core_open(const char *name, unsigned flags, hid_t fapl_id,
     if(H5F_ACC_CREAT & flags) o_flags |= O_CREAT;
     if(H5F_ACC_EXCL & flags) o_flags |= O_EXCL;
 
+    /* Retrieve initial file image info */
+    if(H5P_get(plist, H5F_ACS_FILE_IMAGE_INFO_NAME, &file_image_info) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, NULL, "can't get initial file image info")
+
+    /* If the file image exists and this is an open, make sure the file doesn't exist */
+    HDassert(((file_image_info.buffer != NULL) && (file_image_info.size > 0)) ||
+             ((file_image_info.buffer == NULL) && (file_image_info.size == 0)));
+    if((file_image_info.buffer != NULL) && !(H5F_ACC_CREAT & flags)) {
+        if(HDopen(name, o_flags, 0666) >= 0)
+            HGOTO_ERROR(H5E_FILE, H5E_FILEEXISTS, NULL, "file already exists")
+        
+        /* If backing store is requested, create and stat the file
+         * Note: We are forcing the O_CREAT flag here, even though this is 
+         * technically an open.
+         */
+        if(fa->backing_store) {
+            if((fd = HDopen(name, o_flags | O_CREAT, 0666)) < 0)
+                HGOTO_ERROR(H5E_FILE, H5E_CANTOPENFILE, NULL, "unable to create file")
+            if(HDfstat(fd, &sb) < 0)
+                HSYS_GOTO_ERROR(H5E_FILE, H5E_BADFILE, NULL, "unable to fstat file")
+        } /* end if */
+    }  /* end if */
     /* Open backing store, and get stat() from file.  The only case that backing
      * store is off is when  the backing_store flag is off and H5F_ACC_CREAT is
      * on. */
-    if(fa->backing_store || !(H5F_ACC_CREAT & flags)) {
+    else if(fa->backing_store || !(H5F_ACC_CREAT & flags)) {
         if(fa && (fd = HDopen(name, o_flags, 0666)) < 0)
             HGOTO_ERROR(H5E_FILE, H5E_CANTOPENFILE, NULL, "unable to open file")
         if(HDfstat(fd, &sb) < 0)
@@ -460,6 +484,9 @@ H5FD_core_open(const char *name, unsigned flags, hid_t fapl_id,
     /* If save data in backing store. */
     file->backing_store = fa->backing_store;
 
+    /* Save file image callbacks */
+    file->fi_callbacks = file_image_info.callbacks;
+
     if(fd >= 0) {
         /* Retrieve information for determining uniqueness of file */
 #ifdef H5_HAVE_WIN32_API
@@ -491,51 +518,70 @@ H5FD_core_open(const char *name, unsigned flags, hid_t fapl_id,
         size_t size;
 
         /* Retrieve file size */
-        size = (size_t)sb.st_size;
+        if(file_image_info.buffer && file_image_info.size > 0)
+            size = file_image_info.size;
+        else
+            size = (size_t)sb.st_size;
 
         /* Check if we should allocate the memory buffer and read in existing data */
         if(size) {
-            /* Allocate memory for the file's data */
-            if(NULL == (file->mem = (unsigned char*)H5MM_malloc(size)))
-                HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, NULL, "unable to allocate memory block")
+            /* Allocate memory for the file's data, using the file image callback if available. */
+            if(file->fi_callbacks.image_malloc) {
+                if(NULL == (file->mem = (unsigned char*)file->fi_callbacks.image_malloc(size, H5FD_FILE_IMAGE_OP_FILE_OPEN, file->fi_callbacks.udata)))
+                    HGOTO_ERROR(H5E_FILE, H5E_CANTALLOC, NULL, "image malloc callback failed")
+            } /* end if */
+            else {
+                if(NULL == (file->mem = (unsigned char*)H5MM_malloc(size)))
+                    HGOTO_ERROR(H5E_FILE, H5E_CANTALLOC, NULL, "unable to allocate memory block")
+            } /* end else */
 
             /* Set up data structures */
             file->eof = size;
 
-            /* Read in existing data, being careful of interrupted system calls,
-             * partial results, and the end of the file.
-             */
-            while(size > 0) {
-
-                h5_core_io_t        bytes_in        = 0;    /* # of bytes to read       */
-                h5_core_io_ret_t    bytes_read      = -1;   /* # of bytes actually read */
-                
-                /* Trying to read more bytes than the return type can handle is
-                 * undefined behavior in POSIX.
-                 */
-                if(size > H5_CORE_MAX_IO_BYTES_g)
-                    bytes_in = H5_CORE_MAX_IO_BYTES_g;
-                else
-                    bytes_in = (h5_core_io_t)size;
-                
-                do {
-                    bytes_read = HDread(file->fd, file->mem, bytes_in);
-                } while(-1 == bytes_read && EINTR == errno);
-                
-                if(-1 == bytes_read) { /* error */
-                    int myerrno = errno;
-                    time_t mytime = HDtime(NULL);
-                    HDoff_t myoffset = HDlseek(file->fd, (HDoff_t)0, SEEK_CUR);
-
-                    HGOTO_ERROR(H5E_IO, H5E_READERROR, NULL, "file read failed: time = %s, filename = '%s', file descriptor = %d, errno = %d, error message = '%s', file->mem = %p, size = %lu, offset = %llu", HDctime(&mytime), file->name, file->fd, myerrno, HDstrerror(myerrno), file->mem, (unsigned long)size, (unsigned long long)myoffset);
+            /* If there is an initial file image, copy it, using the callback if possible */
+            if(file_image_info.buffer && file_image_info.size > 0) {
+                if(file->fi_callbacks.image_memcpy) {
+                    if(file->mem != file->fi_callbacks.image_memcpy(file->mem, file_image_info.buffer, size, H5FD_FILE_IMAGE_OP_FILE_OPEN, file->fi_callbacks.udata))
+                        HGOTO_ERROR(H5E_FILE, H5E_CANTCOPY, NULL, "image_memcpy callback failed")
                 } /* end if */
-                
-                HDassert(bytes_read >= 0);
-                HDassert((size_t)bytes_read <= size);
-                
-                size -= (size_t)bytes_read;
-                
-            } /* end while */
+                else
+                    HDmemcpy(file->mem, file_image_info.buffer, size);
+            } /* end if */
+            /* Read in existing data from the file if there is no image */
+            else {
+                /* Read in existing data, being careful of interrupted system calls,
+                 * partial results, and the end of the file.
+                 */
+                while(size > 0) {
+                    h5_core_io_t        bytes_in        = 0;    /* # of bytes to read       */
+                    h5_core_io_ret_t    bytes_read      = -1;   /* # of bytes actually read */
+                    
+                    /* Trying to read more bytes than the return type can handle is
+                     * undefined behavior in POSIX.
+                     */
+                    if(size > H5_CORE_MAX_IO_BYTES_g)
+                        bytes_in = H5_CORE_MAX_IO_BYTES_g;
+                    else
+                        bytes_in = (h5_core_io_t)size;
+                    
+                    do {
+                        bytes_read = HDread(file->fd, file->mem, bytes_in);
+                    } while(-1 == bytes_read && EINTR == errno);
+                    
+                    if(-1 == bytes_read) { /* error */
+                        int myerrno = errno;
+                        time_t mytime = HDtime(NULL);
+                        HDoff_t myoffset = HDlseek(file->fd, (HDoff_t)0, SEEK_CUR);
+
+                        HGOTO_ERROR(H5E_IO, H5E_READERROR, NULL, "file read failed: time = %s, filename = '%s', file descriptor = %d, errno = %d, error message = '%s', file->mem = %p, size = %lu, offset = %llu", HDctime(&mytime), file->name, file->fd, myerrno, HDstrerror(myerrno), file->mem, (unsigned long)size, (unsigned long long)myoffset);
+                    } /* end if */
+                    
+                    HDassert(bytes_read >= 0);
+                    HDassert((size_t)bytes_read <= size);
+                    
+                    size -= (size_t)bytes_read;
+                } /* end while */
+            } /* end else */
         } /* end if */
     } /* end if */
 
@@ -578,8 +624,15 @@ H5FD_core_close(H5FD_t *_file)
         HDclose(file->fd);
     if(file->name)
         H5MM_xfree(file->name);
-    if(file->mem)
-        H5MM_xfree(file->mem);
+    if(file->mem) {
+        /* Use image callback if available */
+        if(file->fi_callbacks.image_free) {
+            if(file->fi_callbacks.image_free(file->mem, H5FD_FILE_IMAGE_OP_FILE_CLOSE, file->fi_callbacks.udata) < 0)
+                HGOTO_ERROR(H5E_FILE, H5E_CANTFREE, FAIL, "image_free callback failed")
+        } /* end if */
+        else
+            H5MM_xfree(file->mem);
+    } /* end if */
     HDmemset(file, 0, sizeof(H5FD_core_t));
     H5MM_xfree(file);
 
@@ -700,9 +753,11 @@ H5FD_core_query(const H5FD_t * _file, unsigned long *flags /* out */)
         *flags |= H5FD_FEAT_ACCUMULATE_METADATA; /* OK to accumulate metadata for faster writes */
         *flags |= H5FD_FEAT_DATA_SIEVE;       /* OK to perform data sieving for faster raw data reads & writes */
         *flags |= H5FD_FEAT_AGGREGATE_SMALLDATA; /* OK to aggregate "small" raw data allocations */
+        *flags |= H5FD_FEAT_ALLOW_FILE_IMAGE;   /* OK to use file image feature with this VFD */
+        *flags |= H5FD_FEAT_CAN_USE_FILE_IMAGE_CALLBACKS;       /* OK to use file image callbacks with this VFD */
 
         /* If the backing store is open, a POSIX file handle is available */
-        if(file->fd >= 0 && file->backing_store)
+        if(file && file->fd >= 0 && file->backing_store)
             *flags |= H5FD_FEAT_POSIX_COMPAT_HANDLE; /* VFD handle is POSIX I/O call compatible */
     } /* end if */
 
@@ -976,9 +1031,16 @@ H5FD_core_write(H5FD_t *_file, H5FD_mem_t UNUSED type, hid_t UNUSED dxpl_id, had
         if((addr + size) % file->increment)
             new_eof += file->increment;
 
-        /* (Re)allocate memory for the file buffer */
-        if(NULL == (x = (unsigned char *)H5MM_realloc(file->mem, new_eof)))
-            HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, FAIL, "unable to allocate memory block of %llu bytes", (unsigned long long)new_eof)
+        /* (Re)allocate memory for the file buffer, using callbacks if available */
+        if(file->fi_callbacks.image_realloc) {
+            if(NULL == (x = (unsigned char *)file->fi_callbacks.image_realloc(file->mem, new_eof, H5FD_FILE_IMAGE_OP_FILE_RESIZE, file->fi_callbacks.udata)))
+                HGOTO_ERROR(H5E_FILE, H5E_CANTALLOC, FAIL, "unable to allocate memory block of %llu bytes with callback", (unsigned long long)new_eof)
+        } /* end if */
+        else {
+            if(NULL == (x = (unsigned char *)H5MM_realloc(file->mem, new_eof)))
+                HGOTO_ERROR(H5E_FILE, H5E_CANTALLOC, FAIL, "unable to allocate memory block of %llu bytes", (unsigned long long)new_eof)
+        } /* end else */
+
 #ifdef H5_CLEAR_MEMORY
 HDmemset(x + file->eof, 0, (size_t)(new_eof - file->eof));
 #endif /* H5_CLEAR_MEMORY */
@@ -989,6 +1051,8 @@ HDmemset(x + file->eof, 0, (size_t)(new_eof - file->eof));
 
     /* Write from BUF to memory */
     HDmemcpy(file->mem + addr, buf, size);
+
+    /* Mark memory buffer as modified */
     file->dirty = TRUE;
 
 done:
@@ -1075,6 +1139,28 @@ done:
  * Purpose:	Makes sure that the true file size is the same (or larger)
  *		than the end-of-address.
  *
+ *		Addendum -- 12/2/11
+ *		For file images opened with the core file driver, it is 
+ *		necessary that we avoid reallocating the core file driver's
+ *		buffer uneccessarily.
+ *
+ *		To this end, I have made the following functional changes
+ *		to this function.  
+ *
+ *		If we are closing, and there is no backing store, this 
+ *		function becomes a no-op.
+ *
+ *		If we are closing, and there is backing store, we set the
+ *		eof to equal the eoa, and truncate the backing store to 
+ *		the new eof
+ *
+ *		If we are not closing, we realloc the buffer to size equal 
+ *		to the smallest multiple of the allocation increment that 
+ *		equals or exceeds the eoa and set the eof accordingly.  
+ *		Note that we no longer truncate	the backing store to the 
+ *		new eof if applicable.
+ *							-- JRM
+ *
  * Return:	Success:	Non-negative
  *		Failure:	Negative
  *
@@ -1085,7 +1171,7 @@ done:
  */
 /* ARGSUSED */
 static herr_t
-H5FD_core_truncate(H5FD_t *_file, hid_t UNUSED dxpl_id, hbool_t UNUSED closing)
+H5FD_core_truncate(H5FD_t *_file, hid_t UNUSED dxpl_id, hbool_t closing)
 {
     H5FD_core_t *file = (H5FD_core_t*)_file;
     size_t new_eof;                             /* New size of memory buffer */
@@ -1095,78 +1181,83 @@ H5FD_core_truncate(H5FD_t *_file, hid_t UNUSED dxpl_id, hbool_t UNUSED closing)
 
     HDassert(file);
 
-    /* Determine new size of memory buffer */
-    H5_ASSIGN_OVERFLOW(new_eof, file->increment * (file->eoa / file->increment), hsize_t, size_t);
-    if(file->eoa % file->increment)
-        new_eof += file->increment;
-
-    /* Extend the file to make sure it's large enough */
-    if(!H5F_addr_eq(file->eof, (haddr_t)new_eof)) {
-        unsigned char *x;       /* Pointer to new buffer for file data */
+    /* if we are closing and not using backing store, do nothing */
+    if(!closing || file->backing_store) {
+        if(closing) /* set eof to eoa */
+            new_eof = file->eoa;
+        else { /* set eof to smallest multiple of increment that exceeds eoa */
+            /* Determine new size of memory buffer */
+            H5_ASSIGN_OVERFLOW(new_eof, file->increment * (file->eoa / file->increment), hsize_t, size_t);
+            if(file->eoa % file->increment)
+                new_eof += file->increment;
+        } /* end else */
+
+        /* Extend the file to make sure it's large enough */
+        if(!H5F_addr_eq(file->eof, (haddr_t)new_eof)) {
+            unsigned char *x;       /* Pointer to new buffer for file data */
+
+            /* (Re)allocate memory for the file buffer, using callback if available */
+            if(file->fi_callbacks.image_realloc) {
+                if(NULL == (x = (unsigned char *)file->fi_callbacks.image_realloc(file->mem, new_eof, H5FD_FILE_IMAGE_OP_FILE_RESIZE, file->fi_callbacks.udata)))
+                  HGOTO_ERROR(H5E_FILE, H5E_CANTALLOC, FAIL, "unable to allocate memory block with callback")
+            } /* end if */
+            else {
+                if(NULL == (x = (unsigned char *)H5MM_realloc(file->mem, new_eof)))
+                    HGOTO_ERROR(H5E_FILE, H5E_CANTALLOC, FAIL, "unable to allocate memory block")
+            } /* end else */
 
-        /* (Re)allocate memory for the file buffer */
-        if(NULL == (x = (unsigned char *)H5MM_realloc(file->mem, new_eof)))
-            HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, FAIL, "unable to allocate memory block")
 #ifdef H5_CLEAR_MEMORY
-if(file->eof < new_eof)
-    HDmemset(x + file->eof, 0, (size_t)(new_eof - file->eof));
+            if(file->eof < new_eof)
+                HDmemset(x + file->eof, 0, (size_t)(new_eof - file->eof));
 #endif /* H5_CLEAR_MEMORY */
-        file->mem = x;
+            file->mem = x;
 
-        /* Update backing store, if using it */
-        if(file->fd >= 0 && file->backing_store) {
+            /* Update backing store, if using it and if closing */
+            if(closing && (file->fd >= 0) && file->backing_store) {
 #ifdef H5_HAVE_WIN32_API
-            LARGE_INTEGER   li;         /* 64-bit (union) integer for SetFilePointer() call */
-            DWORD           dwPtrLow;   /* Low-order pointer bits from SetFilePointer()
-                                         * Only used as an error code here.
-                                         */
-            DWORD           dwError;    /* DWORD error code from GetLastError() */
-            BOOL            bError;     /* Boolean error flag */
-
-            /* Windows uses this odd QuadPart union for 32/64-bit portability */
-            li.QuadPart = (__int64)file->eoa;
-
-            /* Extend the file to make sure it's large enough.
-             *
-             * Since INVALID_SET_FILE_POINTER can technically be a valid return value
-             * from SetFilePointer(), we also need to check GetLastError().
-             */
-            dwPtrLow = SetFilePointer(file->hFile, li.LowPart, &li.HighPart, FILE_BEGIN);
-            if(INVALID_SET_FILE_POINTER == dwPtrLow) {
-                dwError = GetLastError();
-                if(dwError != NO_ERROR )
-                    HGOTO_ERROR(H5E_FILE, H5E_FILEOPEN, FAIL, "unable to set file pointer")
-            }
-
-            bError = SetEndOfFile(file->hFile);
-            if(0 == bError)
-                HGOTO_ERROR(H5E_IO, H5E_SEEKERROR, FAIL, "unable to extend file properly")
+                LARGE_INTEGER   li;         /* 64-bit (union) integer for SetFilePointer() call */
+                DWORD           dwPtrLow;   /* Low-order pointer bits from SetFilePointer()
+                                             * Only used as an error code here.
+                                             */
+                DWORD           dwError;    /* DWORD error code from GetLastError() */
+                BOOL            bError;     /* Boolean error flag */
+
+                /* Windows uses this odd QuadPart union for 32/64-bit portability */
+                li.QuadPart = (__int64)file->eoa;
+
+                /* Extend the file to make sure it's large enough.
+                 *
+                 * Since INVALID_SET_FILE_POINTER can technically be a valid return value
+                 * from SetFilePointer(), we also need to check GetLastError().
+                 */
+                dwPtrLow = SetFilePointer(file->hFile, li.LowPart, &li.HighPart, FILE_BEGIN);
+                if(INVALID_SET_FILE_POINTER == dwPtrLow) {
+                    dwError = GetLastError();
+                    if(dwError != NO_ERROR )
+                        HGOTO_ERROR(H5E_FILE, H5E_FILEOPEN, FAIL, "unable to set file pointer")
+                }
+
+                bError = SetEndOfFile(file->hFile);
+                if(0 == bError)
+                    HGOTO_ERROR(H5E_IO, H5E_SEEKERROR, FAIL, "unable to extend file properly")
 #else /* H5_HAVE_WIN32_API */
 #ifdef H5_VMS
-            /* Reset seek offset to the beginning of the file, so that the file isn't
-             * re-extended later.  This may happen on Open VMS. */
-            if(-1 == HDlseek(file->fd, (HDoff_t)0, SEEK_SET))
-                HSYS_GOTO_ERROR(H5E_IO, H5E_SEEKERROR, FAIL, "unable to seek to proper position")
-#endif
-            if(-1 == HDftruncate(file->fd, (HDoff_t)file->eoa))
-                HSYS_GOTO_ERROR(H5E_IO, H5E_SEEKERROR, FAIL, "unable to extend file properly")
+                /* Reset seek offset to the beginning of the file, so that the file isn't
+                 * re-extended later.  This may happen on Open VMS. */
+                if(-1 == HDlseek(file->fd, (HDoff_t)0, SEEK_SET))
+                    HSYS_GOTO_ERROR(H5E_IO, H5E_SEEKERROR, FAIL, "unable to seek to proper position")
+#endif /* H5_VMS */
+                if(-1 == HDftruncate(file->fd, (HDoff_t)new_eof))
+                    HSYS_GOTO_ERROR(H5E_IO, H5E_SEEKERROR, FAIL, "unable to extend file properly")
 #endif /* H5_HAVE_WIN32_API */
+            } /* end if */
 
-#ifdef H5_VMS
-            /* Reset seek offset to the beginning of the file, so that the file isn't
-             * re-extended later.  This may happen on Open VMS. */
-            if(-1 == HDlseek(file->fd, 0, SEEK_SET))
-                HSYS_GOTO_ERROR(H5E_IO, H5E_SEEKERROR, FAIL, "unable to seek to proper position")
-#endif
-
-            if(-1 == HDftruncate(file->fd, (off_t)new_eof))
-                HSYS_GOTO_ERROR(H5E_IO, H5E_SEEKERROR, FAIL, "unable to extend file properly")
+            /* Update the eof value */
+            file->eof = new_eof;
         } /* end if */
-
-        /* Update the eof value */
-        file->eof = new_eof;
-    } /* end if */
+    } /* end if(file->eof < file->eoa) */
 
 done:
     FUNC_LEAVE_NOAPI(ret_value)
 } /* end H5FD_core_truncate() */
+
diff --git a/src/H5FDfamily.c b/src/H5FDfamily.c
index 17683ce..6f6d757 100644
--- a/src/H5FDfamily.c
+++ b/src/H5FDfamily.c
@@ -995,7 +995,7 @@ H5FD_family_query(const H5FD_t * _file, unsigned long *flags /* out */)
         *flags |= H5FD_FEAT_AGGREGATE_SMALLDATA; /* OK to aggregate "small" raw data allocations */
 
         /* Check for flags that are set by h5repart */
-        if(file->repart_members)
+        if(file && file->repart_members)
             *flags |= H5FD_FEAT_DIRTY_SBLK_LOAD; /* Mark the superblock dirty when it is loaded (so the family member sizes are rewritten) */
     } /* end if */
 
diff --git a/src/H5FDlog.c b/src/H5FDlog.c
index cb5ce3c..0b5c677 100644
--- a/src/H5FDlog.c
+++ b/src/H5FDlog.c
@@ -918,7 +918,7 @@ H5FD_log_query(const H5FD_t *_file, unsigned long *flags /* out */)
         *flags |= H5FD_FEAT_POSIX_COMPAT_HANDLE; /* VFD handle is POSIX I/O call compatible */
 
         /* Check for flags that are set by h5repart */
-        if(file->fam_to_sec2)
+        if(file && file->fam_to_sec2)
             *flags |= H5FD_FEAT_IGNORE_DRVRINFO; /* Ignore the driver info when file is opened (which eliminates it) */
     } /* end if */
 
diff --git a/src/H5FDprivate.h b/src/H5FDprivate.h
index 4f7d059..9c19562 100644
--- a/src/H5FDprivate.h
+++ b/src/H5FDprivate.h
@@ -52,6 +52,29 @@ typedef enum {
 } H5FD_file_op_t;
 
 
+/* Define structure to hold initial file image and other relevant information */
+typedef struct {
+    void *buffer;
+    size_t size;
+    H5FD_file_image_callbacks_t callbacks;
+} H5FD_file_image_info_t;
+
+/* Define default file image info */
+#define H5FD_DEFAULT_FILE_IMAGE_INFO { \
+    /* file image buffer */ NULL,       \
+    /* buffer size */       0,          \
+    { /* Callbacks */                   \
+        /* image_malloc */      NULL,   \
+        /* image_memcpy */      NULL,   \
+        /* image_realloc */     NULL,   \
+        /* image_free */        NULL,   \
+        /* udata_copy */        NULL,   \
+        /* udata_free */        NULL,   \
+        /* udata */             NULL,   \
+    }                                   \
+}
+
+
 /*****************************/
 /* Library Private Variables */
 /*****************************/
@@ -72,17 +95,14 @@ H5_DLL herr_t H5FD_sb_encode(H5FD_t *file, char *name/*out*/, uint8_t *buf);
 H5_DLL herr_t H5FD_sb_decode(H5FD_t *file, const char *name, const uint8_t *buf);
 H5_DLL void *H5FD_fapl_get(H5FD_t *file);
 H5_DLL herr_t H5FD_fapl_open(struct H5P_genplist_t *plist, hid_t driver_id, const void *driver_info);
-H5_DLL herr_t H5FD_fapl_copy(hid_t driver_id, const void *fapl, void **copied_fapl);
 H5_DLL herr_t H5FD_fapl_close(hid_t driver_id, void *fapl);
 H5_DLL herr_t H5FD_dxpl_open(struct H5P_genplist_t *plist, hid_t driver_id, const void *driver_info);
-H5_DLL herr_t H5FD_dxpl_copy(hid_t driver_id, const void *dxpl, void **copied_dxpl);
 H5_DLL herr_t H5FD_dxpl_close(hid_t driver_id, void *dxpl);
 H5_DLL hid_t H5FD_register(const void *cls, size_t size, hbool_t app_ref);
 H5_DLL H5FD_t *H5FD_open(const char *name, unsigned flags, hid_t fapl_id,
 		  haddr_t maxaddr);
 H5_DLL herr_t H5FD_close(H5FD_t *file);
 H5_DLL int H5FD_cmp(const H5FD_t *f1, const H5FD_t *f2);
-H5_DLL int H5FD_query(const H5FD_t *f, unsigned long *flags/*out*/);
 H5_DLL haddr_t H5FD_alloc(H5FD_t *file, hid_t dxpl_id, H5FD_mem_t type, struct H5F_t *f,
     hsize_t size, haddr_t *align_addr, hsize_t *align_size);
 H5_DLL herr_t H5FD_free(H5FD_t *file, hid_t dxpl_id, H5FD_mem_t type, struct H5F_t *f,
diff --git a/src/H5FDpublic.h b/src/H5FDpublic.h
index f495e2d..ab19c68 100644
--- a/src/H5FDpublic.h
+++ b/src/H5FDpublic.h
@@ -222,6 +222,19 @@ typedef enum H5F_mem_t	H5FD_mem_t;
      * instead of the default H5D_ALLOC_TIME_LATE
      */
 #define H5FD_FEAT_ALLOCATE_EARLY        0x00000200
+    /* 
+     * Defining the H5FD_FEAT_ALLOW_FILE_IMAGE for a VFL driver means that
+     * the driver is able to use a file image in the fapl as the initial
+     * contents of a file.
+     */
+#define H5FD_FEAT_ALLOW_FILE_IMAGE      0x00000400
+    /*
+     * Defining the H5FD_FEAT_CAN_USE_FILE_IMAGE_CALLBACKS for a VFL driver
+     * means that the driver is able to use callbacks to make a copy of the
+     * image to store in memory.
+     */
+#define H5FD_FEAT_CAN_USE_FILE_IMAGE_CALLBACKS 0x00000800
+
 
 /* Forward declaration */
 typedef struct H5FD_t H5FD_t;
@@ -291,6 +304,33 @@ struct H5FD_t {
     hsize_t             alignment;      /* Allocation alignment     */
 };
 
+/* Define enum for the source of file image callbacks */
+typedef enum {
+    H5FD_FILE_IMAGE_OP_NO_OP,
+    H5FD_FILE_IMAGE_OP_PROPERTY_LIST_SET,     
+    H5FD_FILE_IMAGE_OP_PROPERTY_LIST_COPY,
+    H5FD_FILE_IMAGE_OP_PROPERTY_LIST_GET,
+    H5FD_FILE_IMAGE_OP_PROPERTY_LIST_CLOSE,
+    H5FD_FILE_IMAGE_OP_FILE_OPEN,
+    H5FD_FILE_IMAGE_OP_FILE_RESIZE,
+    H5FD_FILE_IMAGE_OP_FILE_CLOSE,
+} H5FD_file_image_op_t;
+
+/* Define structure to hold file image callbacks */
+typedef struct {
+    void   *(*image_malloc)(size_t size, H5FD_file_image_op_t file_image_op, 
+                            void *udata);
+    void   *(*image_memcpy)(void *dest, const void *src, size_t size,
+                            H5FD_file_image_op_t file_image_op, void *udata);
+    void   *(*image_realloc)(void *ptr, size_t size, 
+                            H5FD_file_image_op_t file_image_op, void *udata);
+    herr_t  (*image_free)(void *ptr, H5FD_file_image_op_t file_image_op, 
+                          void *udata);
+    void   *(*udata_copy)(void *udata);
+    herr_t  (*udata_free)(void *udata);
+    void *udata;
+} H5FD_file_image_callbacks_t;
+
 #ifdef __cplusplus
 extern "C" {
 #endif
diff --git a/src/H5FDsec2.c b/src/H5FDsec2.c
index 6d4a76a..4201e07 100644
--- a/src/H5FDsec2.c
+++ b/src/H5FDsec2.c
@@ -560,7 +560,7 @@ H5FD_sec2_query(const H5FD_t *_file, unsigned long *flags /* out */)
         *flags |= H5FD_FEAT_POSIX_COMPAT_HANDLE;    /* VFD handle is POSIX I/O call compatible                          */
 
         /* Check for flags that are set by h5repart */
-        if(file->fam_to_sec2)
+        if(file && file->fam_to_sec2)
             *flags |= H5FD_FEAT_IGNORE_DRVRINFO; /* Ignore the driver info when file is opened (which eliminates it) */
     } /* end if */
 
diff --git a/src/H5FDstdio.c b/src/H5FDstdio.c
index b67e01e..4733eba 100644
--- a/src/H5FDstdio.c
+++ b/src/H5FDstdio.c
@@ -13,37 +13,33 @@
  * access to either file, you may request a copy from help@hdfgroup.org.     *
  * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
 
-/*
- * Programmer:  Robb Matzke <matzke@llnl.gov>
- *          Wednesday, October 22, 1997
- *
- * Purpose:     This is the Posix stdio.h I/O subclass of H5Flow.
- *    It also serves as an example of coding a simple file driver,
- *    therefore, it should not use any non-public definitions.
+/* Programmer:  Robb Matzke <matzke@llnl.gov>
+ *              Wednesday, October 22, 1997
  *
- * Notes:  Ported to the new H5FD architecture on 10/18/99 - QAK
+ * Purpose: The C STDIO virtual file driver which only uses calls from stdio.h.
+ *          This also serves as an example of coding a simple file driver,
+ *          therefore, it should not use any non-public definitions.
  *
+ * NOTE:    This driver is not as well tested as the standard SEC2 driver
+ *          and is not intended for production use!
  */
 #include <assert.h>
+#include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <sys/stat.h>
 
-/* Disable certain warnings in PC-Lint: */
-/*lint --emacro( {534, 830}, H5P_FILE_ACCESS) */
-/*lint --emacro( {534, 830}, H5F_ACC_RDWR, H5F_ACC_EXCL) */
-/*lint -esym( 534, H5Eclear2, H5Epush2) */
-
 #include "hdf5.h"
 
-#ifdef H5_HAVE_STDIO_H
-#include <stdio.h>
-#endif
 #ifdef H5_HAVE_UNISTD_H
 #include <unistd.h>
 #endif
 
 #ifdef H5_HAVE_WIN32_API
+/* The following two defines must be before any windows headers are included */
+#define WIN32_LEAN_AND_MEAN    /* Exclude rarely-used stuff from Windows headers */
+#define NOGDI                  /* Exclude Graphic Display Interface macros */
+
 #include <windows.h>
 #include <io.h>
 
@@ -54,7 +50,6 @@
 
 #endif
 
-
 #ifdef MAX
 #undef MAX
 #endif /* MAX */
@@ -63,6 +58,9 @@
 /* The driver identification number, initialized at runtime */
 static hid_t H5FD_STDIO_g = 0;
 
+/* The maximum number of bytes which can be written in a single I/O operation */
+static size_t H5_STDIO_MAX_IO_BYTES_g = (size_t)-1;
+
 /* File operations */
 typedef enum {
     H5FD_STDIO_OP_UNKNOWN=0,
@@ -71,55 +69,71 @@ typedef enum {
     H5FD_STDIO_OP_SEEK=3
 } H5FD_stdio_file_op;
 
-/*
- * The description of a file belonging to this driver. The `eoa' and `eof'
+/* The description of a file belonging to this driver. The 'eoa' and 'eof'
  * determine the amount of hdf5 address space in use and the high-water mark
- * of the file (the current size of the underlying Unix file). The `pos'
+ * of the file (the current size of the underlying Unix file). The 'pos'
  * value is used to eliminate file position updates when they would be a
  * no-op. Unfortunately we've found systems that use separate file position
  * indicators for reading and writing so the lseek can only be eliminated if
  * the current operation is the same as the previous operation.  When opening
- * a file the `eof' will be set to the current file size, `eoa' will be set
- * to zero, `pos' will be set to H5F_ADDR_UNDEF (as it is when an error
- * occurs), and `op' will be set to H5F_OP_UNKNOWN.
+ * a file the 'eof' will be set to the current file size, 'eoa' will be set
+ * to zero, 'pos' will be set to H5F_ADDR_UNDEF (as it is when an error
+ * occurs), and 'op' will be set to H5F_OP_UNKNOWN.
  */
 typedef struct H5FD_stdio_t {
-    H5FD_t  pub;      /*public stuff, must be first  */
-    FILE *  fp;          /*the file handle */
-    haddr_t  eoa;      /*end of allocated region  */
-    haddr_t  eof;      /*end of file; current file size*/
-    haddr_t  pos;      /*current file I/O position  */
-    H5FD_stdio_file_op op;  /*last operation    */
-    unsigned write_access;  /* Flag to indicate the file was opened with write access */
+    H5FD_t      pub;            /* public stuff, must be first      */
+    FILE        *fp;            /* the file handle                  */
+    int         fd;             /* file descriptor (for truncate)   */
+    haddr_t     eoa;            /* end of allocated region          */
+    haddr_t     eof;            /* end of file; current file size   */
+    haddr_t     pos;            /* current file I/O position        */
+    unsigned    write_access;   /* Flag to indicate the file was opened with write access */
+    H5FD_stdio_file_op op;  /* last operation */
 #ifndef H5_HAVE_WIN32_API
-    /*
-     * On most systems the combination of device and i-node number uniquely
-     * identify a file.
+    /* On most systems the combination of device and i-node number uniquely
+     * identify a file.  Note that Cygwin, MinGW and other Windows POSIX
+     * environments have the stat function (which fakes inodes)
+     * and will use the 'device + inodes' scheme as opposed to the
+     * Windows code further below.
      */
-    dev_t  device;      /*file device number    */
-    ino_t  inode;      /*file i-node number    */
+    dev_t           device;     /* file device number   */
+#ifdef H5_VMS
+    ino_t           inode[3];   /* file i-node number   */
 #else
-    /*
-     * On H5_HAVE_WIN32_API the low-order word of a unique identifier associated with the
-     * file and the volume serial number uniquely identify a file. This number
-     * (which, both? -rpm) may change when the system is restarted or when the
-     * file is opened. After a process opens a file, the identifier is
-     * constant until the file is closed. An application can use this
-     * identifier and the volume serial number to determine whether two
-     * handles refer to the same file.
+    ino_t           inode;      /* file i-node number   */
+#endif /* H5_VMS */
+#else
+    /* Files in windows are uniquely identified by the volume serial
+     * number and the file index (both low and high parts).
+     *
+     * There are caveats where these numbers can change, especially
+     * on FAT file systems.  On NTFS, however, a file should keep
+     * those numbers the same until renamed or deleted (though you
+     * can use ReplaceFile() on NTFS to keep the numbers the same
+     * while renaming).
+     *
+     * See the MSDN "BY_HANDLE_FILE_INFORMATION Structure" entry for
+     * more information.
+     *
+     * http://msdn.microsoft.com/en-us/library/aa363788(v=VS.85).aspx
      */
-    DWORD fileindexlo;
-    DWORD fileindexhi;
-#endif
+    DWORD           nFileIndexLow;
+    DWORD           nFileIndexHigh;
+    DWORD           dwVolumeSerialNumber;
+    
+    HANDLE          hFile;      /* Native windows file handle */
+#endif  /* H5_HAVE_WIN32_API */
 } H5FD_stdio_t;
 
 /* Use similar structure as in H5private.h by defining Windows stuff first. */
 #ifdef H5_HAVE_WIN32_API
-    #   define file_fseek  _fseeki64
-    #   define file_offset_t  __int64
-    #   define file_ftruncate  _chsize_s   /* Supported in VS 2005 or newer */
-    #   define file_ftell  _ftelli64
-#endif
+#ifndef H5_HAVE_MINGW
+    #define file_fseek      _fseeki64
+    #define file_offset_t   __int64
+    #define file_ftruncate  _chsize_s   /* Supported in VS 2005 or newer */
+    #define file_ftell      _ftelli64
+#endif /* H5_HAVE_MINGW */
+#endif /* H5_HAVE_WIN32_API */
 
 /* Use file_xxx to indicate these are local macros, avoiding confusing 
  * with the global HD_xxx macros. 
@@ -128,20 +142,19 @@ typedef struct H5FD_stdio_t {
  */
 #ifndef file_fseek
     #ifdef H5_HAVE_FSEEKO64
-    #   define file_fseek  fseeko64
-    #   define file_offset_t  off64_t
-    #   define file_ftruncate  ftruncate64
-    #   define file_ftell  ftello64
+        #define file_fseek      fseeko64
+        #define file_offset_t   off64_t
+        #define file_ftruncate  ftruncate64
+        #define file_ftell      ftello64
     #else
-    #   define file_fseek  fseeko
-    #   define file_offset_t  off_t
-    #   define file_ftruncate  ftruncate
-    #   define file_ftell  ftello
-    #endif
-#endif
-
-/*
- * These macros check for overflow of various quantities.  These macros
+        #define file_fseek      fseeko
+        #define file_offset_t   off_t
+        #define file_ftruncate  ftruncate
+        #define file_ftell      ftello
+    #endif /* H5_HAVE_FSEEKO64 */
+#endif /* file_fseek */
+
+/* These macros check for overflow of various quantities.  These macros
  * assume that file_offset_t is signed and haddr_t and size_t are unsigned.
  *
  * ADDR_OVERFLOW:  Checks whether a file address of type `haddr_t'
@@ -182,38 +195,38 @@ static herr_t H5FD_stdio_flush(H5FD_t *_file, hid_t dxpl_id, unsigned closing);
 static herr_t H5FD_stdio_truncate(H5FD_t *_file, hid_t dxpl_id, hbool_t closing);
 
 static const H5FD_class_t H5FD_stdio_g = {
-    "stdio",                /*name      */
-    MAXADDR,                /*maxaddr    */
-    H5F_CLOSE_WEAK,        /* fc_degree    */
-    H5FD_stdio_term,                            /*terminate             */
-    NULL,          /*sb_size    */
-    NULL,          /*sb_encode    */
-    NULL,          /*sb_decode    */
-    0,             /*fapl_size    */
-    NULL,          /*fapl_get    */
-    NULL,          /*fapl_copy    */
-    NULL,           /*fapl_free    */
-    0,            /*dxpl_size    */
-    NULL,          /*dxpl_copy    */
-    NULL,          /*dxpl_free    */
-    H5FD_stdio_open,                    /*open      */
-    H5FD_stdio_close,                    /*close      */
-    H5FD_stdio_cmp,              /*cmp      */
-    H5FD_stdio_query,                    /*query      */
-    NULL,          /*get_type_map    */
-    H5FD_stdio_alloc,        /*alloc      */
-    NULL,          /*free      */
-    H5FD_stdio_get_eoa,                    /*get_eoa    */
-    H5FD_stdio_set_eoa,                   /*set_eoa    */
-    H5FD_stdio_get_eof,                    /*get_eof    */
-    H5FD_stdio_get_handle,                      /*get_handle            */
-    H5FD_stdio_read,                    /*read      */
-    H5FD_stdio_write,                    /*write      */
-    H5FD_stdio_flush,                    /*flush      */
-    H5FD_stdio_truncate,      /*truncate    */
-    NULL,                                       /*lock                  */
-    NULL,                                       /*unlock                */
-    H5FD_FLMAP_SINGLE                     /*fl_map    */
+    "stdio",                    /* name         */
+    MAXADDR,                    /* maxaddr      */
+    H5F_CLOSE_WEAK,             /* fc_degree    */
+    H5FD_stdio_term,            /* terminate    */
+    NULL,                       /* sb_size      */
+    NULL,                       /* sb_encode    */
+    NULL,                       /* sb_decode    */
+    0,                          /* fapl_size    */
+    NULL,                       /* fapl_get     */
+    NULL,                       /* fapl_copy    */
+    NULL,                       /* fapl_free    */
+    0,                          /* dxpl_size    */
+    NULL,                       /* dxpl_copy    */
+    NULL,                       /* dxpl_free    */
+    H5FD_stdio_open,            /* open         */
+    H5FD_stdio_close,           /* close        */
+    H5FD_stdio_cmp,             /* cmp          */
+    H5FD_stdio_query,           /* query        */
+    NULL,                       /* get_type_map */
+    H5FD_stdio_alloc,           /* alloc        */
+    NULL,                       /* free         */
+    H5FD_stdio_get_eoa,         /* get_eoa      */
+    H5FD_stdio_set_eoa,         /* set_eoa      */
+    H5FD_stdio_get_eof,         /* get_eof      */
+    H5FD_stdio_get_handle,      /* get_handle   */
+    H5FD_stdio_read,            /* read         */
+    H5FD_stdio_write,           /* write        */
+    H5FD_stdio_flush,           /* flush        */
+    H5FD_stdio_truncate,        /* truncate     */
+    NULL,                       /* lock         */
+    NULL,                       /* unlock       */
+    H5FD_FLMAP_SINGLE           /* fl_map       */
 };
 
 
@@ -230,9 +243,6 @@ static const H5FD_class_t H5FD_stdio_g = {
  * Programmer:  Robb Matzke
  *              Thursday, July 29, 1999
  *
- * Modifications:
- *      Stolen from the sec2 driver - QAK, 10/18/99
- *
  *-------------------------------------------------------------------------
  */
 hid_t
@@ -243,8 +253,8 @@ H5FD_stdio_init(void)
 
     if (H5I_VFL!=H5Iget_type(H5FD_STDIO_g))
         H5FD_STDIO_g = H5FDregister(&H5FD_stdio_g);
-    return(H5FD_STDIO_g);
-}
+    return H5FD_STDIO_g;
+} /* end H5FD_stdio_init() */
 
 
 /*---------------------------------------------------------------------------
@@ -263,7 +273,7 @@ static herr_t
 H5FD_stdio_term(void)
 {
     /* Reset VFL ID */
-    H5FD_STDIO_g=0;
+    H5FD_STDIO_g = 0;
 
     return 0;
 } /* end H5FD_stdio_term() */
@@ -281,15 +291,12 @@ H5FD_stdio_term(void)
  * Programmer:  Robb Matzke
  *    Thursday, February 19, 1998
  *
- * Modifications:
- *      Stolen from the sec2 driver - QAK, 10/18/99
- *
  *-------------------------------------------------------------------------
  */
 herr_t
 H5Pset_fapl_stdio(hid_t fapl_id)
 {
-    static const char *func="H5FDset_fapl_stdio";  /*for error reporting*/
+    static const char *func = "H5FDset_fapl_stdio";  /*for error reporting*/
 
     /*NO TRACE*/
 
@@ -300,7 +307,7 @@ H5Pset_fapl_stdio(hid_t fapl_id)
         H5Epush_ret(func, H5E_ERR_CLS, H5E_PLIST, H5E_BADTYPE, "not a file access property list", -1)
 
     return H5Pset_driver(fapl_id, H5FD_STDIO, NULL);
-}
+} /* end H5Pset_fapl_stdio() */
 
 
 /*-------------------------------------------------------------------------
@@ -308,50 +315,44 @@ H5Pset_fapl_stdio(hid_t fapl_id)
  *
  * Purpose:  Create and/or opens a Standard C file as an HDF5 file.
  *
- * Bugs:  H5F_ACC_EXCL has a race condition. (? -QAK)
- *
  * Errors:
- *    IO    CANTOPENFILE  File doesn't exist and CREAT wasn't
- *          specified.
- *    IO    CANTOPENFILE  Fopen failed.
- *    IO    FILEEXISTS  File exists but CREAT and EXCL were
- *          specified.
+ *  IO  CANTOPENFILE    File doesn't exist and CREAT wasn't
+ *                      specified.
+ *  IO  CANTOPENFILE    fopen() failed.
+ *  IO  FILEEXISTS      File exists but CREAT and EXCL were
+ *                      specified.
  *
- * Return:  Success:  A pointer to a new file data structure. The
- *        public fields will be initialized by the
- *        caller, which is always H5FD_open().
+ * Return:
+ *      Success:    A pointer to a new file data structure. The
+ *                  public fields will be initialized by the
+ *                  caller, which is always H5FD_open().
  *
- *    Failure:  NULL
+ *      Failure:    NULL
  *
  * Programmer:  Robb Matzke
  *    Wednesday, October 22, 1997
  *
- * Modifications:
- *      Ported to VFL/H5FD layer - QAK, 10/18/99
- *
  *-------------------------------------------------------------------------
  */
 static H5FD_t *
 H5FD_stdio_open( const char *name, unsigned flags, hid_t fapl_id,
     haddr_t maxaddr)
 {
-    FILE       *f = NULL;
-    unsigned    write_access=0;     /* File opened with write access? */
-    H5FD_stdio_t  *file=NULL;
-    static const char *func="H5FD_stdio_open";  /* Function Name for error reporting */
+    FILE                *f = NULL;
+    unsigned            write_access = 0;           /* File opened with write access? */
+    H5FD_stdio_t        *file = NULL;
+    static const char   *func = "H5FD_stdio_open";  /* Function Name for error reporting */
 #ifdef H5_HAVE_WIN32_API
-  HFILE filehandle;
-  struct _BY_HANDLE_FILE_INFORMATION fileinfo;
-        int fd;
+    struct _BY_HANDLE_FILE_INFORMATION fileinfo;
 #else /* H5_HAVE_WIN32_API */
-    struct stat        sb;
+    struct stat         sb;
 #endif  /* H5_HAVE_WIN32_API */
 
     /* Sanity check on file offsets */
-    assert(sizeof(file_offset_t)>=sizeof(size_t));
+    assert(sizeof(file_offset_t) >= sizeof(size_t));
 
-    /* Shut compiler up */
-    fapl_id=fapl_id;
+    /* Quiet compiler */
+    fapl_id = fapl_id;
 
     /* Clear the error stack */
     H5Eclear2(H5E_DEFAULT);
@@ -359,15 +360,16 @@ H5FD_stdio_open( const char *name, unsigned flags, hid_t fapl_id,
     /* Check arguments */
     if (!name || !*name)
         H5Epush_ret(func, H5E_ERR_CLS, H5E_ARGS, H5E_BADVALUE, "invalid file name", NULL)
-    if (0==maxaddr || HADDR_UNDEF==maxaddr)
+    if (0 == maxaddr || HADDR_UNDEF == maxaddr)
         H5Epush_ret(func, H5E_ERR_CLS, H5E_ARGS, H5E_BADRANGE, "bogus maxaddr", NULL)
     if (ADDR_OVERFLOW(maxaddr))
         H5Epush_ret(func, H5E_ERR_CLS, H5E_ARGS, H5E_OVERFLOW, "maxaddr too large", NULL)
 
+    /* Attempt to open/create the file */
     if (access(name, F_OK) < 0) {
         if ((flags & H5F_ACC_CREAT) && (flags & H5F_ACC_RDWR)) {
             f = fopen(name, "wb+");
-            write_access=1;     /* Note the write access */
+            write_access = 1;     /* Note the write access */
         }
         else
             H5Epush_ret(func, H5E_ERR_CLS, H5E_IO, H5E_CANTOPENFILE, "file doesn't exist and CREAT wasn't specified", NULL)
@@ -378,7 +380,7 @@ H5FD_stdio_open( const char *name, unsigned flags, hid_t fapl_id,
             f = fopen(name, "wb+");
         else
             f = fopen(name, "rb+");
-        write_access=1;     /* Note the write access */
+        write_access = 1;     /* Note the write access */
     } else {
         f = fopen(name, "rb");
     }
@@ -393,30 +395,46 @@ H5FD_stdio_open( const char *name, unsigned flags, hid_t fapl_id,
     file->fp = f;
     file->op = H5FD_STDIO_OP_SEEK;
     file->pos = HADDR_UNDEF;
-    file->write_access=write_access;    /* Note the write_access for later */
+    file->write_access = write_access;    /* Note the write_access for later */
     if(file_fseek(file->fp, (file_offset_t)0, SEEK_END) < 0) {
         file->op = H5FD_STDIO_OP_UNKNOWN;
     } else {
-        file_offset_t x = file_ftell (file->fp);
-        assert (x>=0);
+        file_offset_t x = file_ftell(file->fp);
+        assert (x >= 0);
         file->eof = (haddr_t)x;
     }
 
-    /* The unique key */
+    /* Get the file descriptor (needed for truncate and some Windows information) */
+    file->fd = fileno(file->fp);
+    if(file->fd < 0)
+        H5Epush_ret(func, H5E_ERR_CLS, H5E_FILE, H5E_CANTOPENFILE, "unable to get file descriptor", NULL);
+
+
 #ifdef H5_HAVE_WIN32_API
-/*#error "Needs correct fileindexhi & fileindexlo, code below is from sec2 driver"*/
-    fd = _fileno(f);
-    filehandle = _get_osfhandle(fd);
-    (void)GetFileInformationByHandle((HANDLE)filehandle, &fileinfo);
-    file->fileindexhi = fileinfo.nFileIndexHigh;
-    file->fileindexlo = fileinfo.nFileIndexLow;
-#else
-    fstat(fileno(file->fp), &sb);
+    file->hFile = (HANDLE)_get_osfhandle(file->fd);
+    if(INVALID_HANDLE_VALUE == file->hFile)
+        H5Epush_ret(func, H5E_ERR_CLS, H5E_FILE, H5E_CANTOPENFILE, "unable to get Windows file handle", NULL);
+
+    if(!GetFileInformationByHandle((HANDLE)file->hFile, &fileinfo))
+        H5Epush_ret(func, H5E_ERR_CLS, H5E_FILE, H5E_CANTOPENFILE, "unable to get Windows file desinformationcriptor", NULL);
+
+    file->nFileIndexHigh = fileinfo.nFileIndexHigh;
+    file->nFileIndexLow = fileinfo.nFileIndexLow;
+    file->dwVolumeSerialNumber = fileinfo.dwVolumeSerialNumber;
+#else /* H5_HAVE_WIN32_API */
+    fstat(file->fd, &sb);
     file->device = sb.st_dev;
+#ifdef H5_VMS
+    file->inode[0] = sb.st_ino[0];
+    file->inode[1] = sb.st_ino[1];
+    file->inode[2] = sb.st_ino[2];
+#else /* H5_VMS */
     file->inode = sb.st_ino;
-#endif
-    return((H5FD_t*)file);
-}   /* end H5FD_stdio_open() */
+#endif /* H5_VMS */
+#endif /* H5_HAVE_WIN32_API */
+
+    return (H5FD_t*)file;
+} /* end H5FD_stdio_open() */
 
 
 /*-------------------------------------------------------------------------
@@ -432,16 +450,13 @@ H5FD_stdio_open( const char *name, unsigned flags, hid_t fapl_id,
  * Programmer:  Robb Matzke
  *    Wednesday, October 22, 1997
  *
- * Modifications:
- *      Ported to VFL/H5FD layer - QAK, 10/18/99
- *
  *-------------------------------------------------------------------------
  */
 static herr_t
 H5FD_stdio_close(H5FD_t *_file)
 {
     H5FD_stdio_t  *file = (H5FD_stdio_t*)_file;
-    static const char *func="H5FD_stdio_close";  /* Function Name for error reporting */
+    static const char *func = "H5FD_stdio_close";  /* Function Name for error reporting */
 
     /* Clear the error stack */
     H5Eclear2(H5E_DEFAULT);
@@ -451,8 +466,8 @@ H5FD_stdio_close(H5FD_t *_file)
 
     free(file);
 
-    return(0);
-}
+    return 0;
+} /* end H5FD_stdio_close() */
 
 
 /*-------------------------------------------------------------------------
@@ -461,17 +476,14 @@ H5FD_stdio_close(H5FD_t *_file)
  * Purpose:  Compares two files belonging to this driver using an
  *    arbitrary (but consistent) ordering.
  *
- * Return:  Success:  A value like strcmp()
+ * Return:
+ *      Success:    A value like strcmp()
  *
- *    Failure:  never fails (arguments were checked by the
- *        caller).
+ *      Failure:    never fails (arguments were checked by the caller).
  *
  * Programmer:  Robb Matzke
  *              Thursday, July 29, 1999
  *
- * Modifications:
- *      Stolen from the sec2 driver - QAK, 10/18/99
- *
  *-------------------------------------------------------------------------
  */
 static int
@@ -484,30 +496,37 @@ H5FD_stdio_cmp(const H5FD_t *_f1, const H5FD_t *_f2)
     H5Eclear2(H5E_DEFAULT);
 
 #ifdef H5_HAVE_WIN32_API
-    if (f1->fileindexhi < f2->fileindexhi) return -1;
-    if (f1->fileindexhi > f2->fileindexhi) return 1;
+    if(f1->dwVolumeSerialNumber < f2->dwVolumeSerialNumber) return -1;
+    if(f1->dwVolumeSerialNumber > f2->dwVolumeSerialNumber) return 1;
 
-    if (f1->fileindexlo < f2->fileindexlo) return -1;
-    if (f1->fileindexlo > f2->fileindexlo) return 1;
+    if(f1->nFileIndexHigh < f2->nFileIndexHigh) return -1;
+    if(f1->nFileIndexHigh > f2->nFileIndexHigh) return 1;
 
-#else
+    if(f1->nFileIndexLow < f2->nFileIndexLow) return -1;
+    if(f1->nFileIndexLow > f2->nFileIndexLow) return 1;
+#else /* H5_HAVE_WIN32_API */
 #ifdef H5_DEV_T_IS_SCALAR
-    if (f1->device < f2->device) return -1;
-    if (f1->device > f2->device) return 1;
+    if(f1->device < f2->device) return -1;
+    if(f1->device > f2->device) return 1;
 #else /* H5_DEV_T_IS_SCALAR */
     /* If dev_t isn't a scalar value on this system, just use memcmp to
      * determine if the values are the same or not.  The actual return value
      * shouldn't really matter...
      */
-    if(memcmp(&(f1->device),&(f2->device),sizeof(dev_t))<0) return -1;
-    if(memcmp(&(f1->device),&(f2->device),sizeof(dev_t))>0) return 1;
+    if(memcmp(&(f1->device),&(f2->device),sizeof(dev_t)) < 0) return -1;
+    if(memcmp(&(f1->device),&(f2->device),sizeof(dev_t)) > 0) return 1;
 #endif /* H5_DEV_T_IS_SCALAR */
+#ifdef H5_VMS
+    if(memcmp(&(f1->inode), &(f2->inode), 3 * sizeof(ino_t)) < 0) return -1;
+    if(memcmp(&(f1->inode), &(f2->inode), 3 * sizeof(ino_t)) > 0) return 1;
+#else /* H5_VMS */
+    if(f1->inode < f2->inode) return -1;
+    if(f1->inode > f2->inode) return 1;
+#endif /* H5_VMS */
+#endif /* H5_HAVE_WIN32_API */
 
-    if (f1->inode < f2->inode) return -1;
-    if (f1->inode > f2->inode) return 1;
-#endif
     return 0;
-}
+} /* H5FD_stdio_cmp() */
 
 
 /*-------------------------------------------------------------------------
@@ -523,14 +542,12 @@ H5FD_stdio_cmp(const H5FD_t *_f1, const H5FD_t *_f2)
  * Programmer:  Quincey Koziol
  *              Friday, August 25, 2000
  *
- * Modifications:
- *
  *-------------------------------------------------------------------------
  */
 static herr_t
 H5FD_stdio_query(const H5FD_t *_f, unsigned long *flags /* out */)
 {
-    /* Shut compiler up */
+    /* Quiet the compiler */
     _f=_f;
 
     /* Set the VFL feature flags that this driver supports */
@@ -542,37 +559,35 @@ H5FD_stdio_query(const H5FD_t *_f, unsigned long *flags /* out */)
         *flags|=H5FD_FEAT_AGGREGATE_SMALLDATA; /* OK to aggregate "small" raw data allocations */
     }
 
-    return(0);
-}
+    return 0;
+} /* end H5FD_stdio_query() */
 
 
 /*-------------------------------------------------------------------------
  * Function:  H5FD_stdio_alloc
  *
- * Purpose:  Allocates file memory. If fseeko isn't available, makes
+ * Purpose:     Allocates file memory. If fseeko isn't available, makes
  *              sure the file size isn't bigger than 2GB because the
  *              parameter OFFSET of fseek is of the type LONG INT, limiting
  *              the file size to 2GB.
  *
- * Return:  Success:  Address of new memory
+ * Return:
+ *      Success:    Address of new memory
  *
- *    Failure:  HADDR_UNDEF
+ *      Failure:    HADDR_UNDEF
  *
  * Programmer:  Raymond Lu
  *              30 March 2007
  *
- * Modifications:
- *
  *-------------------------------------------------------------------------
  */
 static haddr_t
 H5FD_stdio_alloc(H5FD_t *_file, H5FD_mem_t /*UNUSED*/ type, hid_t /*UNUSED*/ dxpl_id, hsize_t size)
 {
-    H5FD_stdio_t  *file = (H5FD_stdio_t*)_file;
-    haddr_t    addr;
-    haddr_t ret_value;          /* Return value */
+    H5FD_stdio_t    *file = (H5FD_stdio_t*)_file;
+    haddr_t         addr;
 
-    /* Shut compiler up */
+    /* Quiet compiler */
     type = type;
     dxpl_id = dxpl_id;
 
@@ -591,19 +606,16 @@ H5FD_stdio_alloc(H5FD_t *_file, H5FD_mem_t /*UNUSED*/ type, hid_t /*UNUSED*/ dxp
 
     file->eoa = addr + size;
 
-    /* Set return value */
-    ret_value = addr;
-
-    return(ret_value);
-}   /* H5FD_stdio_alloc() */
+    return addr;
+} /* end H5FD_stdio_alloc() */
 
 
 /*-------------------------------------------------------------------------
  * Function:  H5FD_stdio_get_eoa
  *
  * Purpose:  Gets the end-of-address marker for the file. The EOA marker
- *    is the first address past the last byte allocated in the
- *    format address space.
+ *           is the first address past the last byte allocated in the
+ *           format address space.
  *
  * Return:  Success:  The end-of-address marker.
  *
@@ -612,28 +624,21 @@ H5FD_stdio_alloc(H5FD_t *_file, H5FD_mem_t /*UNUSED*/ type, hid_t /*UNUSED*/ dxp
  * Programmer:  Robb Matzke
  *              Monday, August  2, 1999
  *
- * Modifications:
- *              Stolen from the sec2 driver - QAK, 10/18/99
- *
- *              Raymond Lu
- *              21 Dec. 2006
- *              Added the parameter TYPE.  It's only used for MULTI driver.
- *
  *-------------------------------------------------------------------------
  */
 static haddr_t
-H5FD_stdio_get_eoa(const H5FD_t *_file, H5FD_mem_t /*unused*/ type)
+H5FD_stdio_get_eoa(const H5FD_t *_file, H5FD_mem_t /*UNUSED*/ type)
 {
-    const H5FD_stdio_t  *file = (const H5FD_stdio_t *)_file;
+    const H5FD_stdio_t *file = (const H5FD_stdio_t *)_file;
 
     /* Clear the error stack */
     H5Eclear2(H5E_DEFAULT);
 
-    /* Shut compiler up */
+    /* Quiet compiler */
     type = type;
 
-    return(file->eoa);
-}
+    return file->eoa;
+} /* end H5FD_stdio_get_eoa() */
 
 
 /*-------------------------------------------------------------------------
@@ -645,33 +650,27 @@ H5FD_stdio_get_eoa(const H5FD_t *_file, H5FD_mem_t /*unused*/ type)
  *
  * Return:  Success:  0
  *
- *    Failure:  -1
+ *    Failure:  Does not fail
  *
  * Programmer:  Robb Matzke
  *              Thursday, July 29, 1999
  *
- * Modifications:
- *              Stolen from the sec2 driver - QAK, 10/18/99
- *
- *              Raymond Lu
- *              21 Dec. 2006
- *              Added the parameter TYPE.  It's only used for MULTI driver.
  *-------------------------------------------------------------------------
  */
 static herr_t
-H5FD_stdio_set_eoa(H5FD_t *_file, H5FD_mem_t /*unused*/ type, haddr_t addr)
+H5FD_stdio_set_eoa(H5FD_t *_file, H5FD_mem_t /*UNUSED*/ type, haddr_t addr)
 {
     H5FD_stdio_t  *file = (H5FD_stdio_t*)_file;
 
     /* Clear the error stack */
     H5Eclear2(H5E_DEFAULT);
 
-    /* Shut compiler up */
+    /* Quiet the compiler */
     type = type;
 
     file->eoa = addr;
 
-    return(0);
+    return 0;
 }
 
 
@@ -691,9 +690,6 @@ H5FD_stdio_set_eoa(H5FD_t *_file, H5FD_mem_t /*unused*/ type, haddr_t addr)
  * Programmer:  Robb Matzke
  *              Thursday, July 29, 1999
  *
- * Modifications:
- *      Stolen from the sec2 driver - QAK, 10/18/99
- *
  *-------------------------------------------------------------------------
  */
 static haddr_t
@@ -704,8 +700,8 @@ H5FD_stdio_get_eof(const H5FD_t *_file)
     /* Clear the error stack */
     H5Eclear2(H5E_DEFAULT);
 
-    return(MAX(file->eof, file->eoa));
-}
+    return MAX(file->eof, file->eoa);
+} /* end H5FD_stdio_get_eof() */
 
 
 /*-------------------------------------------------------------------------
@@ -718,64 +714,56 @@ H5FD_stdio_get_eof(const H5FD_t *_file)
  * Programmer:     Raymond Lu
  *                 Sept. 16, 2002
  *
- * Modifications:
- *
  *-------------------------------------------------------------------------
  */
 static herr_t
 H5FD_stdio_get_handle(H5FD_t *_file, hid_t fapl, void** file_handle)
 {
     H5FD_stdio_t       *file = (H5FD_stdio_t *)_file;
-    static const char  *func="H5FD_stdio_get_handle";  /* Function Name for error reporting */
+    static const char  *func = "H5FD_stdio_get_handle";  /* Function Name for error reporting */
 
-    /* Shut compiler up */
-    fapl=fapl;
+    /* Quiet the compiler */
+    fapl = fapl;
 
     /* Clear the error stack */
     H5Eclear2(H5E_DEFAULT);
 
     *file_handle = &(file->fp);
-    if(*file_handle==NULL)
+    if(*file_handle == NULL)
         H5Epush_ret(func, H5E_ERR_CLS, H5E_IO, H5E_WRITEERROR, "get handle failed", -1)
-    return(0);
-}
+
+    return 0;
+} /* end H5FD_stdio_get_handle() */
 
 
 /*-------------------------------------------------------------------------
- * Function:  H5F_stdio_read
+ * Function:  H5FD_stdio_read
  *
  * Purpose:  Reads SIZE bytes beginning at address ADDR in file LF and
  *    places them in buffer BUF.  Reading past the logical or
  *    physical end of file returns zeros instead of failing.
  *
  * Errors:
- *    IO    READERROR  Fread failed.
- *    IO    SEEKERROR  Fseek failed.
+ *    IO    READERROR  fread failed.
+ *    IO    SEEKERROR  fseek failed.
  *
  * Return:  Non-negative on success/Negative on failure
  *
  * Programmer:  Robb Matzke
  *    Wednesday, October 22, 1997
  *
- * Modifications:
- *    June 2, 1998  Albert Cheng
- *    Added xfer_mode argument
- *
- *      Ported to VFL/H5FD layer - QAK, 10/18/99
- *
  *-------------------------------------------------------------------------
  */
 static herr_t
 H5FD_stdio_read(H5FD_t *_file, H5FD_mem_t type, hid_t dxpl_id, haddr_t addr, size_t size,
     void *buf/*out*/)
 {
-    size_t    n;
     H5FD_stdio_t    *file = (H5FD_stdio_t*)_file;
-    static const char *func="H5FD_stdio_read";  /* Function Name for error reporting */
+    static const char *func = "H5FD_stdio_read";  /* Function Name for error reporting */
 
-    /* Shut compiler up */
-    type=type;
-    dxpl_id=dxpl_id;
+    /* Quiet the compiler */
+    type = type;
+    dxpl_id = dxpl_id;
 
     /* Clear the error stack */
     H5Eclear2(H5E_DEFAULT);
@@ -790,16 +778,14 @@ H5FD_stdio_read(H5FD_t *_file, H5FD_mem_t type, hid_t dxpl_id, haddr_t addr, siz
 
     /* Check easy cases */
     if (0 == size)
-        return(0);
+        return 0;
     if ((haddr_t)addr >= file->eof) {
         memset(buf, 0, size);
-        return(0);
+        return 0;
     }
 
-    /*
-     * Seek to the correct file position.
-     */
-    if (!(file->op == H5FD_STDIO_OP_READ || file->op==H5FD_STDIO_OP_SEEK) ||
+    /* Seek to the correct file position. */
+    if (!(file->op == H5FD_STDIO_OP_READ || file->op == H5FD_STDIO_OP_SEEK) ||
             file->pos != addr) {
         if (file_fseek(file->fp, (file_offset_t)addr, SEEK_SET) < 0) {
             file->op = H5FD_STDIO_OP_UNKNOWN;
@@ -809,59 +795,70 @@ H5FD_stdio_read(H5FD_t *_file, H5FD_mem_t type, hid_t dxpl_id, haddr_t addr, siz
         file->pos = addr;
     }
 
-    /*
-     * Read zeros past the logical end of file (physical is handled below)
-     */
+    /* Read zeros past the logical end of file (physical is handled below) */
     if (addr + size > file->eof) {
         size_t nbytes = (size_t) (addr + size - file->eof);
         memset((unsigned char *)buf + size - nbytes, 0, nbytes);
         size -= nbytes;
     }
 
-    /*
-     * Read the data.  Since we're reading single-byte values, a partial read
+    /* Read the data.  Since we're reading single-byte values, a partial read
      * will advance the file position by N.  If N is zero or an error
      * occurs then the file position is undefined.
      */
-    n = fread(buf, (size_t)1, size, file->fp);
-    if(n == 0 && ferror(file->fp)) {
-        file->op = H5FD_STDIO_OP_UNKNOWN;
-        file->pos = HADDR_UNDEF;
-        H5Epush_ret(func, H5E_ERR_CLS, H5E_IO, H5E_READERROR, "fread failed", -1)
-    } else if (n < size) {
-        memset((unsigned char *)buf + n, 0, (size - n));
-    }
+    while(size > 0) {
 
-    /*
-     * Update the file position data.
-     */
+        size_t bytes_in        = 0;    /* # of bytes to read       */
+        size_t bytes_read      = 0;    /* # of bytes actually read */
+        size_t item_size       = 1;    /* size of items in bytes */
+
+        if(size > H5_STDIO_MAX_IO_BYTES_g)
+            bytes_in = H5_STDIO_MAX_IO_BYTES_g;
+        else
+            bytes_in = size;
+
+        bytes_read = fread(buf, item_size, bytes_in, file->fp);
+
+        if(0 == bytes_read && ferror(file->fp)) { /* error */
+            file->op = H5FD_STDIO_OP_UNKNOWN;
+            file->pos = HADDR_UNDEF;
+            H5Epush_ret(func, H5E_ERR_CLS, H5E_IO, H5E_READERROR, "fread failed", -1)
+        } /* end if */
+        
+        if(0 == bytes_read && feof(file->fp)) {
+            /* end of file but not end of format address space */
+            memset((unsigned char *)buf, 0, size);
+            break;
+        } /* end if */
+        
+        size -= bytes_read;
+        addr += (haddr_t)bytes_read;
+        buf = (char *)buf + bytes_read;
+    } /* end while */
+
+    /* Update the file position data. */
     file->op = H5FD_STDIO_OP_READ;
-    file->pos = addr+n; /*checked for overflow above*/
-    return(0);
+    file->pos = addr;
+
+    return 0;
 }
 
 
 /*-------------------------------------------------------------------------
- * Function:  H5F_stdio_write
+ * Function:  H5FD_stdio_write
  *
  * Purpose:  Writes SIZE bytes from the beginning of BUF into file LF at
  *    file address ADDR.
  *
  * Errors:
- *    IO    SEEKERROR  Fseek failed.
- *    IO    WRITEERROR  Fwrite failed.
+ *    IO    SEEKERROR   fseek failed.
+ *    IO    WRITEERROR  fwrite failed.
  *
  * Return:  Non-negative on success/Negative on failure
  *
  * Programmer:  Robb Matzke
  *    Wednesday, October 22, 1997
  *
- * Modifications:
- *    June 2, 1998  Albert Cheng
- *    Added xfer_mode argument
- *
- *      Ported to VFL/H5FD layer - QAK, 10/18/99
- *
  *-------------------------------------------------------------------------
  */
 static herr_t
@@ -869,26 +866,24 @@ H5FD_stdio_write(H5FD_t *_file, H5FD_mem_t type, hid_t dxpl_id, haddr_t addr,
     size_t size, const void *buf)
 {
     H5FD_stdio_t    *file = (H5FD_stdio_t*)_file;
-    static const char *func="H5FD_stdio_write";  /* Function Name for error reporting */
+    static const char *func = "H5FD_stdio_write";  /* Function Name for error reporting */
 
-    /* Shut compiler up */
-    dxpl_id=dxpl_id;
-    type=type;
+    /* Quiet the compiler */
+    dxpl_id = dxpl_id;
+    type = type;
 
     /* Clear the error stack */
     H5Eclear2(H5E_DEFAULT);
 
     /* Check for overflow conditions */
-    if (HADDR_UNDEF==addr)
+    if (HADDR_UNDEF == addr)
         H5Epush_ret (func, H5E_ERR_CLS, H5E_IO, H5E_OVERFLOW, "file address overflowed", -1)
     if (REGION_OVERFLOW(addr, size))
         H5Epush_ret (func, H5E_ERR_CLS, H5E_IO, H5E_OVERFLOW, "file address overflowed", -1)
-    if (addr+size>file->eoa)
+    if (addr+size > file->eoa)
         H5Epush_ret (func, H5E_ERR_CLS, H5E_IO, H5E_OVERFLOW, "file address overflowed", -1)
 
-    /*
-     * Seek to the correct file position.
-     */
+    /* Seek to the correct file position. */
     if ((file->op != H5FD_STDIO_OP_WRITE && file->op != H5FD_STDIO_OP_SEEK) ||
                 file->pos != addr) {
         if (file_fseek(file->fp, (file_offset_t)addr, SEEK_SET) < 0) {
@@ -899,33 +894,51 @@ H5FD_stdio_write(H5FD_t *_file, H5FD_mem_t type, hid_t dxpl_id, haddr_t addr,
         file->pos = addr;
     }
 
-    /*
-     * Write the buffer.  On successful return, the file position will be
-     * advanced by the number of bytes read.  Otherwise nobody knows where it
-     * is.
+    /* Write the buffer.  On successful return, the file position will be
+     * advanced by the number of bytes read.  On failure, the file position is
+     * undefined.
      */
-    if(size != fwrite(buf, (size_t)1, size, file->fp)) {
-        file->op = H5FD_STDIO_OP_UNKNOWN;
-        file->pos = HADDR_UNDEF;
-        H5Epush_ret(func, H5E_ERR_CLS, H5E_IO, H5E_WRITEERROR, "fwrite failed", -1)
+    while(size > 0) {
+
+        size_t bytes_in        = 0;    /* # of bytes to write  */
+        size_t bytes_wrote     = 0;    /* # of bytes written   */
+        size_t item_size       = 1;    /* size of items in bytes */
+
+        if(size > H5_STDIO_MAX_IO_BYTES_g)
+            bytes_in = H5_STDIO_MAX_IO_BYTES_g;
+        else
+            bytes_in = size;
+
+        bytes_wrote = fwrite(buf, item_size, bytes_in, file->fp);
+
+        if(bytes_wrote != bytes_in || (0 == bytes_wrote && ferror(file->fp))) { /* error */
+            file->op = H5FD_STDIO_OP_UNKNOWN;
+            file->pos = HADDR_UNDEF;
+            H5Epush_ret(func, H5E_ERR_CLS, H5E_IO, H5E_WRITEERROR, "fwrite failed", -1)
+        } /* end if */
+        
+        assert(bytes_wrote > 0);
+        assert((size_t)bytes_wrote <= size);
+
+        size -= bytes_wrote;
+        addr += (haddr_t)bytes_wrote;
+        buf = (const char *)buf + bytes_wrote;
     }
 
-    /*
-     * Update seek optimizing data.
-     */
+    /* Update seek optimizing data. */
     file->op = H5FD_STDIO_OP_WRITE;
-    file->pos = addr + size;
+    file->pos = addr;
 
     /* Update EOF if necessary */
-    if (file->pos>file->eof)
+    if (file->pos > file->eof)
         file->eof = file->pos;
 
-    return(0);
+    return 0;
 }
 
 
 /*-------------------------------------------------------------------------
- * Function:  H5F_stdio_flush
+ * Function:  H5FD_stdio_flush
  *
  * Purpose:  Makes sure that all data is on disk.
  *
@@ -946,7 +959,7 @@ H5FD_stdio_flush(H5FD_t *_file, hid_t dxpl_id, unsigned closing)
     H5FD_stdio_t  *file = (H5FD_stdio_t*)_file;
     static const char *func = "H5FD_stdio_flush";  /* Function Name for error reporting */
 
-    /* Shut compiler up */
+    /* Quiet the compiler */
     dxpl_id = dxpl_id;
 
     /* Clear the error stack */
@@ -954,7 +967,6 @@ H5FD_stdio_flush(H5FD_t *_file, hid_t dxpl_id, unsigned closing)
 
     /* Only try to flush the file if we have write access */
     if(file->write_access) {
-        /* Flush */
         if(!closing) {
             if(fflush(file->fp) < 0)
                 H5Epush_ret(func, H5E_ERR_CLS, H5E_IO, H5E_WRITEERROR, "fflush failed", -1)
@@ -965,12 +977,12 @@ H5FD_stdio_flush(H5FD_t *_file, hid_t dxpl_id, unsigned closing)
         } /* end if */
     } /* end if */
 
-    return(0);
+    return 0;
 } /* end H5FD_stdio_flush() */
 
 
 /*-------------------------------------------------------------------------
- * Function:  H5F_stdio_truncate
+ * Function:  H5FD_stdio_truncate
  *
  * Purpose:  Makes sure that the true file size is the same (or larger)
  *    than the end-of-address.
@@ -984,9 +996,6 @@ H5FD_stdio_flush(H5FD_t *_file, hid_t dxpl_id, unsigned closing)
  * Programmer:  Quincey Koziol
  *    Thursday, January 31, 2008
  *
- * Modifications:
- *  Vailin Choi; June 2010
- *  Fix for window failures manifested from tests in mf.c.
  *-------------------------------------------------------------------------
  */
 static herr_t
@@ -995,7 +1004,7 @@ H5FD_stdio_truncate(H5FD_t *_file, hid_t dxpl_id, hbool_t closing)
     H5FD_stdio_t  *file = (H5FD_stdio_t*)_file;
     static const char *func = "H5FD_stdio_truncate";  /* Function Name for error reporting */
 
-    /* Shut compiler up */
+    /* Quiet the compiler */
     dxpl_id = dxpl_id;
     closing = closing;
 
@@ -1006,30 +1015,42 @@ H5FD_stdio_truncate(H5FD_t *_file, hid_t dxpl_id, hbool_t closing)
     if(file->write_access) {
         /* Makes sure that the true file size is the same as the end-of-address. */
         if(file->eoa != file->eof) {
-            int fd = fileno(file->fp);     /* File descriptor for HDF5 file */
 
 #ifdef H5_HAVE_WIN32_API
-            HFILE filehandle;   /* Windows file handle */
-            LARGE_INTEGER li;   /* 64-bit integer for SetFilePointer() call */
+            LARGE_INTEGER   li;         /* 64-bit (union) integer for SetFilePointer() call */
+            DWORD           dwPtrLow;   /* Low-order pointer bits from SetFilePointer()
+                                         * Only used as an error code here.
+                                         */
+            DWORD           dwError;    /* DWORD error code from GetLastError() */
+            BOOL            bError;     /* Boolean error flag */
 
-      /* Reset seek offset to beginning of file, so that file isn't re-extended later */
+            /* Reset seek offset to beginning of file, so that file isn't re-extended later */
             rewind(file->fp);
 
-            /* Map the posix file handle to a Windows file handle */
-            filehandle = _get_osfhandle(fd);
-
-            /* Translate 64-bit integers into form Windows wants */
-            /* [This algorithm is from the Windows documentation for SetFilePointer()] */
-            li.QuadPart = (LONGLONG)file->eoa;
-            (void)SetFilePointer((HANDLE)filehandle, li.LowPart, &li.HighPart, FILE_BEGIN);
-            if(SetEndOfFile((HANDLE)filehandle) == 0)
+            /* Windows uses this odd QuadPart union for 32/64-bit portability */
+            li.QuadPart = (__int64)file->eoa;
+
+            /* Extend the file to make sure it's large enough.
+             *
+             * Since INVALID_SET_FILE_POINTER can technically be a valid return value
+             * from SetFilePointer(), we also need to check GetLastError().
+             */
+            dwPtrLow = SetFilePointer(file->hFile, li.LowPart, &li.HighPart, FILE_BEGIN);
+            if(INVALID_SET_FILE_POINTER == dwPtrLow) {
+                dwError = GetLastError();
+                if(dwError != NO_ERROR )
+                    H5Epush_ret(func, H5E_ERR_CLS, H5E_FILE, H5E_FILEOPEN, "unable to set file pointer", -1)
+            }
+            
+            bError = SetEndOfFile(file->hFile);
+            if(0 == bError)
                 H5Epush_ret(func, H5E_ERR_CLS, H5E_IO, H5E_SEEKERROR, "unable to truncate/extend file properly", -1)
 #else /* H5_HAVE_WIN32_API */
             /* Reset seek offset to beginning of file, so that file isn't re-extended later */
             rewind(file->fp);
 
             /* Truncate file to proper length */
-            if(-1 == file_ftruncate(fd, (file_offset_t)file->eoa))
+            if(-1 == file_ftruncate(file->fd, (file_offset_t)file->eoa))
                 H5Epush_ret(func, H5E_ERR_CLS, H5E_IO, H5E_SEEKERROR, "unable to truncate/extend file properly", -1)
 #endif /* H5_HAVE_WIN32_API */
 
@@ -1044,10 +1065,10 @@ H5FD_stdio_truncate(H5FD_t *_file, hid_t dxpl_id, hbool_t closing)
     else {
         /* Double-check for problems */
         if(file->eoa > file->eof)
-            H5Epush_ret(func, H5E_ERR_CLS, H5E_IO, H5E_TRUNCATED, "eoa>eof!", -1)
-      } /* end else */
+            H5Epush_ret(func, H5E_ERR_CLS, H5E_IO, H5E_TRUNCATED, "eoa > eof!", -1)
+    } /* end else */
 
-    return(0);
+    return 0;
 } /* end H5FD_stdio_truncate() */
 
 
diff --git a/src/H5FSprivate.h b/src/H5FSprivate.h
index ca7104c..f6a0034 100644
--- a/src/H5FSprivate.h
+++ b/src/H5FSprivate.h
@@ -155,7 +155,7 @@ typedef struct H5FS_stat_t {
 } H5FS_stat_t;
 
 /* Typedef for iteration operations */
-typedef herr_t (*H5FS_operator_t)(const H5FS_section_info_t *sect,
+typedef herr_t (*H5FS_operator_t)(H5FS_section_info_t *sect,
         void *operator_data/*in,out*/);
 
 
diff --git a/src/H5FSsection.c b/src/H5FSsection.c
index 914fa58..0f126c2 100644
--- a/src/H5FSsection.c
+++ b/src/H5FSsection.c
@@ -2244,7 +2244,7 @@ H5FS_sect_assert(const H5FS_t *fspace)
     hsize_t separate_obj;       /* The number of separate objects managed */
 
     FUNC_ENTER_NOAPI_NOINIT_NOERR
-#ifndef QAK
+#ifdef QAK
 HDfprintf(stderr, "%s: fspace->tot_sect_count = %Hu\n", "H5FS_sect_assert", fspace->tot_sect_count);
 #endif /* QAK */
 
diff --git a/src/H5Fmpi.c b/src/H5Fmpi.c
index 0f612be..966528a 100644
--- a/src/H5Fmpi.c
+++ b/src/H5Fmpi.c
@@ -202,7 +202,7 @@ H5Fset_mpi_atomicity(hid_t file_id, hbool_t flag)
     herr_t       ret_value = SUCCEED;
 
     FUNC_ENTER_API(FAIL)
-    H5TRACE2("e", "iMi", file_id, flag);
+    H5TRACE2("e", "ib", file_id, flag);
 
     /* Check args */
     if(NULL == (file = (H5F_t *)H5I_object_verify(file_id, H5I_FILE)))
@@ -242,7 +242,7 @@ H5Fget_mpi_atomicity(hid_t file_id, hbool_t *flag)
     herr_t     ret_value = SUCCEED;
 
     FUNC_ENTER_API(FAIL)
-    H5TRACE2("e", "iMi", file_id, flag);
+    H5TRACE2("e", "i*b", file_id, flag);
 
     /* Check args */
     if(NULL == (file = (H5F_t *)H5I_object_verify(file_id, H5I_FILE)))
diff --git a/src/H5Fprivate.h b/src/H5Fprivate.h
index 939bc3f..7e45cfa 100644
--- a/src/H5Fprivate.h
+++ b/src/H5Fprivate.h
@@ -417,6 +417,7 @@ typedef struct H5F_blk_aggr_t H5F_blk_aggr_t;
 #define H5F_ACS_LATEST_FORMAT_NAME              "latest_format" /* 'Use latest format version' flag */
 #define H5F_ACS_WANT_POSIX_FD_NAME              "want_posix_fd" /* Internal: query the file descriptor from the core VFD, instead of the memory address */
 #define H5F_ACS_EFC_SIZE_NAME                   "efc_size"      /* Size of external file cache */
+#define H5F_ACS_FILE_IMAGE_INFO_NAME            "file_image_info" /* struct containing initial file image and callback info */
 
 /* ======================== File Mount properties ====================*/
 #define H5F_MNT_SYM_LOCAL_NAME 		"local"                 /* Whether absolute symlinks local to file. */
@@ -530,8 +531,8 @@ H5_DLL H5F_t *H5F_get_parent(const H5F_t *f);
 H5_DLL unsigned H5F_get_nmounts(const H5F_t *f);
 H5_DLL hid_t H5F_get_access_plist(H5F_t *f, hbool_t app_ref);
 H5_DLL hid_t H5F_get_id(H5F_t *file, hbool_t app_ref);
-H5_DLL size_t H5F_get_obj_count(const H5F_t *f, unsigned types, hbool_t app_ref);
-H5_DLL size_t H5F_get_obj_ids(const H5F_t *f, unsigned types, size_t max_objs, hid_t *obj_id_list, hbool_t app_ref);
+H5_DLL herr_t H5F_get_obj_count(const H5F_t *f, unsigned types, hbool_t app_ref, size_t *obj_id_count_ptr);
+H5_DLL herr_t H5F_get_obj_ids(const H5F_t *f, unsigned types, size_t max_objs, hid_t *oid_list, hbool_t app_ref, size_t *obj_id_count_ptr);
 H5_DLL struct H5VL_class_t *H5F_get_vol_cls(const H5F_t *f);
 
 /* Functions than retrieve values set/cached from the superblock/FCPL */
diff --git a/src/H5Fpublic.h b/src/H5Fpublic.h
index d88538b..f32b3e0 100644
--- a/src/H5Fpublic.h
+++ b/src/H5Fpublic.h
@@ -192,6 +192,7 @@ H5_DLL herr_t H5Fmount(hid_t loc, const char *name, hid_t child, hid_t plist);
 H5_DLL herr_t H5Funmount(hid_t loc, const char *name);
 H5_DLL hssize_t H5Fget_freespace(hid_t file_id);
 H5_DLL herr_t H5Fget_filesize(hid_t file_id, hsize_t *size);
+H5_DLL ssize_t H5Fget_file_image(hid_t file_id, void * buf_ptr, size_t buf_len);
 H5_DLL herr_t H5Fget_mdc_config(hid_t file_id,
 				H5AC_cache_config_t * config_ptr);
 H5_DLL herr_t H5Fset_mdc_config(hid_t file_id,
diff --git a/src/H5Gname.c b/src/H5Gname.c
index 62875dc..576d866 100644
--- a/src/H5Gname.c
+++ b/src/H5Gname.c
@@ -782,7 +782,7 @@ done:
 /*-------------------------------------------------------------------------
  * Function: H5G_name_replace_cb
  *
- * Purpose: H5I_search callback function to replace group entry names
+ * Purpose: H5I_iterate callback function to replace group entry names
  *
  * Return: Success: 0, Failure: -1
  *
@@ -1166,15 +1166,18 @@ H5G_name_replace(const H5O_link_t *lnk, H5G_names_op_t op, H5F_t *src_file,
 
             /* Search through group IDs */
             if(search_group)
-                H5I_search(H5I_GROUP, H5G_name_replace_cb, &names, FALSE);
+                if(H5I_iterate(H5I_GROUP, H5G_name_replace_cb, &names, FALSE) < 0)
+		    HGOTO_ERROR(H5E_SYM, H5E_BADITER, FAIL, "can't iterate over groups")
 
             /* Search through dataset IDs */
             if(search_dataset)
-                H5I_search(H5I_DATASET, H5G_name_replace_cb, &names, FALSE);
+                if(H5I_iterate(H5I_DATASET, H5G_name_replace_cb, &names, FALSE) < 0)
+		    HGOTO_ERROR(H5E_SYM, H5E_BADITER, FAIL, "can't iterate over datasets")
 
             /* Search through datatype IDs */
             if(search_datatype)
-                H5I_search(H5I_DATATYPE, H5G_name_replace_cb, &names, FALSE);
+                if(H5I_iterate(H5I_DATATYPE, H5G_name_replace_cb, &names, FALSE) < 0)
+		    HGOTO_ERROR(H5E_SYM, H5E_BADITER, FAIL, "can't iterate over datatypes")
         } /* end if */
     } /* end if */
 
diff --git a/src/H5Goh.c b/src/H5Goh.c
index 194e3ec..c6115db 100644
--- a/src/H5Goh.c
+++ b/src/H5Goh.c
@@ -81,7 +81,8 @@ const H5O_obj_class_t H5O_OBJ_GROUP[1] = {{
     H5O_group_open, 		/* open an object of this class */
     H5O_group_create, 		/* create an object of this class */
     H5O_group_get_oloc,		/* get an object header location for an object */
-    H5O_group_bh_info 		/* get the index & heap info for an object */
+    H5O_group_bh_info, 		/* get the index & heap info for an object */
+    NULL 			/* flush an opened object of this class */
 }};
 
 /* Declare the external free list to manage the H5O_ginfo_t struct */
diff --git a/src/H5HF.c b/src/H5HF.c
index 9c911fd..a9750c9 100644
--- a/src/H5HF.c
+++ b/src/H5HF.c
@@ -156,9 +156,6 @@ H5HF_create(H5F_t *f, hid_t dxpl_id, const H5HF_create_t *cparam)
     H5HF_t *ret_value;          /* Return value */
 
     FUNC_ENTER_NOAPI(NULL)
-#ifdef QAK
-HDfprintf(stderr, "%s: Called\n", FUNC);
-#endif /* QAK */
 
     /*
      * Check arguments.
@@ -234,14 +231,8 @@ H5HF_open(H5F_t *f, hid_t dxpl_id, haddr_t fh_addr)
     HDassert(H5F_addr_defined(fh_addr));
 
     /* Load the heap header into memory */
-#ifdef QAK
-HDfprintf(stderr, "%s: fh_addr = %a\n", FUNC, fh_addr);
-#endif /* QAK */
     if(NULL == (hdr = H5HF_hdr_protect(f, dxpl_id, fh_addr, H5AC_READ)))
         HGOTO_ERROR(H5E_HEAP, H5E_CANTPROTECT, NULL, "unable to protect fractal heap header")
-#ifdef QAK
-HDfprintf(stderr, "%s: hdr->rc = %u, hdr->fspace = %p\n", FUNC, hdr->rc, hdr->fspace);
-#endif /* QAK */
 
     /* Check for pending heap deletion */
     if(hdr->pending_delete)
@@ -361,9 +352,6 @@ H5HF_insert(H5HF_t *fh, hid_t dxpl_id, size_t size, const void *obj,
     herr_t ret_value = SUCCEED;
 
     FUNC_ENTER_NOAPI(FAIL)
-#ifdef QAK
-HDfprintf(stderr, "%s: size = %Zu\n", FUNC, size);
-#endif /* QAK */
 
     /* Sanity check */
     HDassert(fh);
@@ -406,9 +394,6 @@ HGOTO_ERROR(H5E_HEAP, H5E_UNSUPPORTED, FAIL, "'write once' managed blocks not su
     } /* end else */
 
 done:
-#ifdef QAK
-HDfprintf(stderr, "%s: Leaving, ret_value = %d\n", FUNC, ret_value);
-#endif /* QAK */
     FUNC_LEAVE_NOAPI(ret_value)
 } /* end H5HF_insert() */
 
@@ -580,9 +565,6 @@ H5HF_write(H5HF_t *fh, hid_t dxpl_id, void *_id, hbool_t UNUSED *id_changed,
     herr_t ret_value = SUCCEED;         /* Return value */
 
     FUNC_ENTER_NOAPI(FAIL)
-#ifdef QAK
-HDfprintf(stderr, "%s: Called\n", FUNC);
-#endif /* QAK */
 
     /*
      * Check arguments.
@@ -720,9 +702,6 @@ H5HF_remove(H5HF_t *fh, hid_t dxpl_id, const void *_id)
     herr_t ret_value = SUCCEED;         /* Return value */
 
     FUNC_ENTER_NOAPI(FAIL)
-#ifdef QAK
-HDfprintf(stderr, "%s: Called\n", FUNC);
-#endif /* QAK */
 
     /*
      * Check arguments.
@@ -814,17 +793,9 @@ H5HF_close(H5HF_t *fh, hid_t dxpl_id)
          *      a reference loop and the objects couldn't be removed from
          *      the metadata cache - QAK)
          */
-#ifdef QAK
-HDfprintf(stderr, "%s; fh->hdr->man_iter_off = %Hu\n", FUNC, fh->hdr->man_iter_off);
-HDfprintf(stderr, "%s; fh->hdr->man_size = %Hu\n", FUNC, fh->hdr->man_size);
-HDfprintf(stderr, "%s; fh->hdr->rc = %Zu\n", FUNC, fh->hdr->rc);
-#endif /* QAK */
         if(H5HF_man_iter_ready(&fh->hdr->next_block))
             if(H5HF_man_iter_reset(&fh->hdr->next_block) < 0)
                 HGOTO_ERROR(H5E_HEAP, H5E_CANTRELEASE, FAIL, "can't reset block iterator")
-#ifdef QAK
-HDfprintf(stderr, "%s; After iterator reset fh->hdr->rc = %Zu\n", FUNC, fh->hdr->rc);
-#endif /* QAK */
 
         /* Shut down the huge object information */
         /* (Can't put this in header "destroy" routine, because it has
@@ -900,9 +871,6 @@ H5HF_delete(H5F_t *f, hid_t dxpl_id, haddr_t fh_addr)
     HDassert(H5F_addr_defined(fh_addr));
 
     /* Lock the heap header into memory */
-#ifdef QAK
-HDfprintf(stderr, "%s: fh_addr = %a\n", FUNC, fh_addr);
-#endif /* QAK */
     if(NULL == (hdr = H5HF_hdr_protect(f, dxpl_id, fh_addr, H5AC_WRITE)))
         HGOTO_ERROR(H5E_HEAP, H5E_CANTPROTECT, FAIL, "unable to protect fractal heap header")
 
diff --git a/src/H5HFbtree2.c b/src/H5HFbtree2.c
index 023344c..34b74d7 100644
--- a/src/H5HFbtree2.c
+++ b/src/H5HFbtree2.c
@@ -352,7 +352,7 @@ HDfprintf(stderr, "%s: nrecord = {%a, %Hu, %Hu}\n", "H5HF_huge_bt2_indir_found",
 herr_t
 H5HF_huge_bt2_indir_remove(const void *nrecord, void *_udata)
 {
-    H5HF_huge_remove_ud1_t *udata = (H5HF_huge_remove_ud1_t *)_udata;   /* User callback data */
+    H5HF_huge_remove_ud_t *udata = (H5HF_huge_remove_ud_t *)_udata;   /* User callback data */
     herr_t ret_value = SUCCEED;         /* Return value */
 
     FUNC_ENTER_NOAPI_NOINIT
@@ -570,7 +570,7 @@ HDfprintf(stderr, "%s: nrecord = {%a, %Hu, %x, %Hu, %Hu}\n", "H5HF_huge_bt2_filt
 herr_t
 H5HF_huge_bt2_filt_indir_remove(const void *nrecord, void *_udata)
 {
-    H5HF_huge_remove_ud1_t *udata = (H5HF_huge_remove_ud1_t *)_udata;   /* User callback data */
+    H5HF_huge_remove_ud_t *udata = (H5HF_huge_remove_ud_t *)_udata;   /* User callback data */
     herr_t ret_value = SUCCEED;         /* Return value */
 
     FUNC_ENTER_NOAPI_NOINIT
@@ -759,7 +759,7 @@ H5HF_huge_bt2_filt_indir_debug(FILE *stream, const H5F_t UNUSED *f, hid_t UNUSED
 herr_t
 H5HF_huge_bt2_dir_remove(const void *nrecord, void *_udata)
 {
-    H5HF_huge_remove_ud1_t *udata = (H5HF_huge_remove_ud1_t *)_udata;   /* User callback data */
+    H5HF_huge_remove_ud_t *udata = (H5HF_huge_remove_ud_t *)_udata;   /* User callback data */
     herr_t ret_value = SUCCEED;         /* Return value */
 
     FUNC_ENTER_NOAPI_NOINIT
@@ -984,7 +984,7 @@ HDfprintf(stderr, "%s: nrecord = {%a, %Hu, %x, %Hu}\n", "H5HF_huge_bt2_filt_dir_
 herr_t
 H5HF_huge_bt2_filt_dir_remove(const void *nrecord, void *_udata)
 {
-    H5HF_huge_remove_ud1_t *udata = (H5HF_huge_remove_ud1_t *)_udata;   /* User callback data */
+    H5HF_huge_remove_ud_t *udata = (H5HF_huge_remove_ud_t *)_udata;   /* User callback data */
     herr_t ret_value = SUCCEED;         /* Return value */
 
     FUNC_ENTER_NOAPI_NOINIT
diff --git a/src/H5HFdbg.c b/src/H5HFdbg.c
index 4289c02..caaedc7 100644
--- a/src/H5HFdbg.c
+++ b/src/H5HFdbg.c
@@ -172,39 +172,31 @@ H5HF_dtable_debug(H5HF_dtable_t *dtable, FILE *stream, int indent, int fwidth)
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5HF_hdr_debug
+ * Function:	H5HF_hdr_print
  *
- * Purpose:	Prints debugging info about a fractal heap header.
+ * Purpose:	Prints info about a fractal heap header.
  *
  * Return:	Non-negative on success/Negative on failure
  *
  * Programmer:	Quincey Koziol
- *		koziol@ncsa.uiuc.edu
- *		Feb 24 2006
+ *		koziol@hdfgroup.org
+ *		Feb 23 2012
  *
  *-------------------------------------------------------------------------
  */
-herr_t
-H5HF_hdr_debug(H5F_t *f, hid_t dxpl_id, haddr_t addr, FILE *stream, int indent, int fwidth)
+void
+H5HF_hdr_print(const H5HF_hdr_t *hdr, hid_t dxpl_id, hbool_t dump_internal, FILE *stream, int indent, int fwidth)
 {
-    H5HF_hdr_t	*hdr = NULL;             /* Fractal heap header info */
-    herr_t      ret_value = SUCCEED;    /* Return value */
-
-    FUNC_ENTER_NOAPI(FAIL)
+    FUNC_ENTER_NOAPI_NOINIT
 
     /*
      * Check arguments.
      */
-    HDassert(f);
-    HDassert(H5F_addr_defined(addr));
+    HDassert(hdr);
     HDassert(stream);
     HDassert(indent >= 0);
     HDassert(fwidth >= 0);
 
-    /* Load the fractal heap header */
-    if(NULL == (hdr = H5HF_hdr_protect(f, dxpl_id, addr, H5AC_READ)))
-	HGOTO_ERROR(H5E_HEAP, H5E_CANTPROTECT, FAIL, "unable to protect fractal heap header")
-
     /* Print opening message */
     HDfprintf(stream, "%*sFractal Heap Header...\n", indent, "");
 
@@ -277,10 +269,66 @@ H5HF_hdr_debug(H5F_t *f, hid_t dxpl_id, haddr_t addr, FILE *stream, int indent,
                       "Filter mask for root direct block:",
                       hdr->pline_root_direct_filter_mask);
         } /* end if */
-        H5O_debug_id(H5O_PLINE_ID, f, dxpl_id, &(hdr->pline), stream,
+        H5O_debug_id(H5O_PLINE_ID, hdr->f, dxpl_id, &(hdr->pline), stream,
                              indent + 3, MAX(0, fwidth - 3));
     } /* end if */
 
+    /* Print internal (runtime) information, if requested */
+    if(dump_internal) {
+        HDfprintf(stream, "%*sFractal Heap Header Internal Information:\n", indent, "");
+
+        /* Dump root iblock, if there is one */
+        HDfprintf(stream, "%*s%-*s %x\n", indent + 3, "", MAX(0, fwidth - 3),
+                  "Root indirect block flags:",
+                  hdr->root_iblock_flags);
+        HDfprintf(stream, "%*s%-*s %p\n", indent + 3, "", MAX(0, fwidth - 3),
+                  "Root indirect block pointer:",
+                  hdr->root_iblock);
+        if(hdr->root_iblock)
+            H5HF_iblock_print(hdr->root_iblock, dump_internal, stream, indent + 3, fwidth);
+    } /* end if */
+
+    FUNC_LEAVE_NOAPI_VOID
+} /* end H5HF_hdr_print() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:	H5HF_hdr_debug
+ *
+ * Purpose:	Prints debugging info about a fractal heap header.
+ *
+ * Return:	Non-negative on success/Negative on failure
+ *
+ * Programmer:	Quincey Koziol
+ *		koziol@ncsa.uiuc.edu
+ *		Feb 24 2006
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5HF_hdr_debug(H5F_t *f, hid_t dxpl_id, haddr_t addr, FILE *stream, int indent, int fwidth)
+{
+    H5HF_hdr_t	*hdr = NULL;             /* Fractal heap header info */
+    herr_t      ret_value = SUCCEED;    /* Return value */
+
+    FUNC_ENTER_NOAPI(FAIL)
+
+    /*
+     * Check arguments.
+     */
+    HDassert(f);
+    HDassert(H5F_addr_defined(addr));
+    HDassert(stream);
+    HDassert(indent >= 0);
+    HDassert(fwidth >= 0);
+
+    /* Load the fractal heap header */
+    if(NULL == (hdr = H5HF_hdr_protect(f, dxpl_id, addr, H5AC_READ)))
+	HGOTO_ERROR(H5E_HEAP, H5E_CANTPROTECT, FAIL, "unable to protect fractal heap header")
+
+    /* Print the information about the heap's header */
+    H5HF_hdr_print(hdr, dxpl_id, FALSE, stream, indent, fwidth);
+
 done:
     if(hdr && H5AC_unprotect(f, dxpl_id, H5AC_FHEAP_HDR, addr, hdr, H5AC__NO_FLAGS_SET) < 0)
         HDONE_ERROR(H5E_HEAP, H5E_PROTECT, FAIL, "unable to release fractal heap header")
@@ -303,9 +351,9 @@ done:
  *-------------------------------------------------------------------------
  */
 static herr_t
-H5HF_dblock_debug_cb(const H5FS_section_info_t *_sect, void *_udata)
+H5HF_dblock_debug_cb(H5FS_section_info_t *_sect, void *_udata)
 {
-    const H5HF_free_section_t *sect = (const H5HF_free_section_t *)_sect;       /* Section to dump info */
+    H5HF_free_section_t *sect = (H5HF_free_section_t *)_sect;       /* Section to dump info */
     H5HF_debug_iter_ud1_t *udata = (H5HF_debug_iter_ud1_t *)_udata;         /* User data for callbacks */
     haddr_t sect_start, sect_end;       /* Section's beginning and ending offsets */
     haddr_t dblock_start, dblock_end;   /* Direct block's beginning and ending offsets */
@@ -501,51 +549,39 @@ done:
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5HF_iblock_debug
+ * Function:	H5HF_iblock_print
  *
  * Purpose:	Prints debugging info about a fractal heap indirect block.
  *
  * Return:	Non-negative on success/Negative on failure
  *
  * Programmer:	Quincey Koziol
- *		koziol@ncsa.uiuc.edu
- *		Mar  7 2006
+ *		koziol@hdfgroup.org
+ *		Feb 23 2012
  *
  *-------------------------------------------------------------------------
  */
-herr_t
-H5HF_iblock_debug(H5F_t *f, hid_t dxpl_id, haddr_t addr, FILE *stream,
-    int indent, int fwidth, haddr_t hdr_addr, unsigned nrows)
+void
+H5HF_iblock_print(const H5HF_indirect_t *iblock,
+    hbool_t dump_internal, FILE *stream, int indent, int fwidth)
 {
-    H5HF_hdr_t	*hdr = NULL;            /* Fractal heap header info */
-    H5HF_indirect_t *iblock = NULL;     /* Fractal heap direct block info */
-    hbool_t did_protect;                /* Whether we protected the indirect block or not */
+    const H5HF_hdr_t *hdr;              /* Pointer to heap's header */
     char temp_str[64];                  /* Temporary string, for formatting */
     size_t	u, v;                   /* Local index variable */
-    herr_t      ret_value = SUCCEED;    /* Return value */
 
-    FUNC_ENTER_NOAPI(FAIL)
+    FUNC_ENTER_NOAPI_NOINIT
 
     /*
      * Check arguments.
      */
-    HDassert(f);
-    HDassert(H5F_addr_defined(addr));
+    HDassert(iblock);
+    HDassert(iblock->hdr);
     HDassert(stream);
     HDassert(indent >= 0);
     HDassert(fwidth >= 0);
-    HDassert(H5F_addr_defined(hdr_addr));
-    HDassert(nrows > 0);
 
-    /* Load the fractal heap header */
-    if(NULL == (hdr = H5HF_hdr_protect(f, dxpl_id, hdr_addr, H5AC_READ)))
-	HGOTO_ERROR(H5E_HEAP, H5E_CANTPROTECT, FAIL, "unable to protect fractal heap header")
-
-    /*
-     * Load the heap indirect block
-     */
-    if(NULL == (iblock = H5HF_man_iblock_protect(hdr, dxpl_id, addr, nrows, NULL, 0, FALSE, H5AC_READ, &did_protect)))
-	HGOTO_ERROR(H5E_HEAP, H5E_CANTLOAD, FAIL, "unable to load fractal heap indirect block")
+    /* Set up convenience variables */
+    hdr = iblock->hdr;
 
     /* Print opening message */
     HDfprintf(stream, "%*sFractal Heap Indirect Block...\n", indent, "");
@@ -623,6 +659,75 @@ H5HF_iblock_debug(H5F_t *f, hid_t dxpl_id, haddr_t addr, FILE *stream,
         HDfprintf(stream, "%*s%-*s\n", indent + 3, "", MAX(0, fwidth - 3),
                   "<none>");
 
+    /* Print internal (runtime) information, if requested */
+    if(dump_internal) {
+        HDfprintf(stream, "%*sFractal Indirect Block Internal Information:\n", indent, "");
+
+        /* Print general information */
+        HDfprintf(stream, "%*s%-*s %Zu\n", indent + 3, "", MAX(0, fwidth - 3),
+                  "Reference count:",
+                  iblock->rc);
+
+        /* Print parent's information */
+        HDfprintf(stream, "%*s%-*s %p\n", indent + 3, "", MAX(0, fwidth - 3),
+                  "Parent indirect block address:",
+                  iblock->parent);
+        if(iblock->parent)
+            H5HF_iblock_print(iblock->parent, TRUE, stream, indent + 6, fwidth);
+    } /* end if */
+
+    FUNC_LEAVE_NOAPI_VOID
+} /* end H5HF_iblock_print() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:	H5HF_iblock_debug
+ *
+ * Purpose:	Prints debugging info about a fractal heap indirect block.
+ *
+ * Return:	Non-negative on success/Negative on failure
+ *
+ * Programmer:	Quincey Koziol
+ *		koziol@ncsa.uiuc.edu
+ *		Mar  7 2006
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5HF_iblock_debug(H5F_t *f, hid_t dxpl_id, haddr_t addr, FILE *stream,
+    int indent, int fwidth, haddr_t hdr_addr, unsigned nrows)
+{
+    H5HF_hdr_t	*hdr = NULL;            /* Fractal heap header info */
+    H5HF_indirect_t *iblock = NULL;     /* Fractal heap direct block info */
+    hbool_t did_protect;                /* Whether we protected the indirect block or not */
+    herr_t      ret_value = SUCCEED;    /* Return value */
+
+    FUNC_ENTER_NOAPI(FAIL)
+
+    /*
+     * Check arguments.
+     */
+    HDassert(f);
+    HDassert(H5F_addr_defined(addr));
+    HDassert(stream);
+    HDassert(indent >= 0);
+    HDassert(fwidth >= 0);
+    HDassert(H5F_addr_defined(hdr_addr));
+    HDassert(nrows > 0);
+
+    /* Load the fractal heap header */
+    if(NULL == (hdr = H5HF_hdr_protect(f, dxpl_id, hdr_addr, H5AC_READ)))
+	HGOTO_ERROR(H5E_HEAP, H5E_CANTPROTECT, FAIL, "unable to protect fractal heap header")
+
+    /*
+     * Load the heap indirect block
+     */
+    if(NULL == (iblock = H5HF_man_iblock_protect(hdr, dxpl_id, addr, nrows, NULL, 0, FALSE, H5AC_READ, &did_protect)))
+	HGOTO_ERROR(H5E_HEAP, H5E_CANTLOAD, FAIL, "unable to load fractal heap indirect block")
+
+    /* Print the information about the heap's indirect block */
+    H5HF_iblock_print(iblock, FALSE, stream, indent, fwidth);
+
 done:
     if(iblock && H5HF_man_iblock_unprotect(iblock, dxpl_id, H5AC__NO_FLAGS_SET, did_protect) < 0)
         HDONE_ERROR(H5E_HEAP, H5E_PROTECT, FAIL, "unable to release fractal heap direct block")
@@ -647,9 +752,9 @@ done:
  *-------------------------------------------------------------------------
  */
 static herr_t
-H5HF_sects_debug_cb(const H5FS_section_info_t *_sect, void *_udata)
+H5HF_sects_debug_cb(H5FS_section_info_t *_sect, void *_udata)
 {
-    const H5HF_free_section_t *sect = (const H5HF_free_section_t *)_sect;       /* Section to dump info */
+    H5HF_free_section_t *sect = (H5HF_free_section_t *)_sect;       /* Section to dump info */
     H5HF_debug_iter_ud2_t *udata = (H5HF_debug_iter_ud2_t *)_udata;         /* User data for callbacks */
     herr_t      ret_value = SUCCEED;    /* Return value */
 
diff --git a/src/H5HFhuge.c b/src/H5HFhuge.c
index 3bbd137..6f0b48e 100644
--- a/src/H5HFhuge.c
+++ b/src/H5HFhuge.c
@@ -899,7 +899,7 @@ done:
 herr_t
 H5HF_huge_remove(H5HF_hdr_t *hdr, hid_t dxpl_id, const uint8_t *id)
 {
-    H5HF_huge_remove_ud1_t udata;       /* User callback data for v2 B-tree remove call */
+    H5HF_huge_remove_ud_t udata;       /* User callback data for v2 B-tree remove call */
     herr_t ret_value = SUCCEED;         /* Return value */
 
     FUNC_ENTER_NOAPI_NOINIT
@@ -1072,7 +1072,7 @@ done:
 herr_t
 H5HF_huge_delete(H5HF_hdr_t *hdr, hid_t dxpl_id)
 {
-    H5HF_huge_remove_ud1_t udata;       /* User callback data for v2 B-tree remove call */
+    H5HF_huge_remove_ud_t udata;       /* User callback data for v2 B-tree remove call */
     H5B2_remove_t op;                   /* Callback for v2 B-tree removal */
     herr_t ret_value = SUCCEED;         /* Return value */
 
diff --git a/src/H5HFiblock.c b/src/H5HFiblock.c
index 6c19b4f..342e228 100644
--- a/src/H5HFiblock.c
+++ b/src/H5HFiblock.c
@@ -140,8 +140,17 @@ H5HF_iblock_pin(H5HF_indirect_t *iblock)
     else {
         /* Check for pinning the root indirect block */
         if(iblock->block_off == 0) {
-            HDassert(iblock->hdr->root_iblock == NULL);
-            iblock->hdr->root_iblock = iblock;
+            /* Sanity check - shouldn't be recursively pinning root indirect block */
+            HDassert(0 == (iblock->hdr->root_iblock_flags & H5HF_ROOT_IBLOCK_PINNED));
+
+            /* Check if we should set the root iblock pointer */
+            if(0 == iblock->hdr->root_iblock_flags) {
+                HDassert(NULL == iblock->hdr->root_iblock);
+                iblock->hdr->root_iblock = iblock;
+            } /* end if */
+
+            /* Indicate that the root indirect block is pinned */
+            iblock->hdr->root_iblock_flags |= H5HF_ROOT_IBLOCK_PINNED;
         } /* end if */
     } /* end if */
 
@@ -192,12 +201,21 @@ H5HF_iblock_unpin(H5HF_indirect_t *iblock)
         par_iblock->child_iblocks[indir_idx] = NULL;
     } /* end if */
     else {
-        /* Check for unpinning the root indirect block */
+        /* Check for root indirect block */
         if(iblock->block_off == 0) {
-            HDassert(iblock->hdr->root_iblock);
-            iblock->hdr->root_iblock = NULL;
+            /* Sanity check - shouldn't be recursively unpinning root indirect block */
+            HDassert(iblock->hdr->root_iblock_flags & H5HF_ROOT_IBLOCK_PINNED);
+
+            /* Check if we should reset the root iblock pointer */
+            if(H5HF_ROOT_IBLOCK_PINNED == iblock->hdr->root_iblock_flags) {
+                HDassert(NULL != iblock->hdr->root_iblock);
+                iblock->hdr->root_iblock = NULL;
+            } /* end if */
+
+            /* Indicate that the root indirect block is unpinned */
+            iblock->hdr->root_iblock_flags &= ~(H5HF_ROOT_IBLOCK_PINNED);
         } /* end if */
-    } /* end if */
+    } /* end else */
 
     /* Mark block as evictable again */
     if(H5AC_unpin_entry(iblock) < 0)
@@ -273,18 +291,23 @@ H5HF_iblock_decr(H5HF_indirect_t *iblock)
 
     /* Mark block as evictable again when no child blocks depend on it */
     if(iblock->rc == 0) {
-        if(H5HF_iblock_unpin(iblock) < 0)
-            HGOTO_ERROR(H5E_HEAP, H5E_CANTUNPIN, FAIL, "unable to unpin fractal heap indirect block")
+        H5HF_hdr_t *hdr;			/* Fractal heap header */
+        haddr_t iblock_addr;		/* Address of fractal heap */
+        hbool_t expunge_iblock = FALSE;     /* Whether to expunge indirect block from heap */
+
+        /* Set up convenience variables */
+        hdr = iblock->hdr;
+        iblock_addr = iblock->addr;
 
         if(iblock->nchildren == 0) {
             /* Check for deleting root indirect block (and no root direct block) */
-            if(iblock->block_off == 0 && iblock->hdr->man_dtable.curr_root_rows > 0) {
+            if(iblock->block_off == 0 && hdr->man_dtable.curr_root_rows > 0) {
                 /* Reset root pointer information */
-                iblock->hdr->man_dtable.curr_root_rows = 0;
-                iblock->hdr->man_dtable.table_addr = HADDR_UNDEF;
+                hdr->man_dtable.curr_root_rows = 0;
+                hdr->man_dtable.table_addr = HADDR_UNDEF;
 
                 /* Reset header information back to "empty heap" state */
-                if(H5HF_hdr_empty(iblock->hdr) < 0)
+                if(H5HF_hdr_empty(hdr) < 0)
                     HGOTO_ERROR(H5E_HEAP, H5E_CANTSHRINK, FAIL, "can't make heap empty")
             } /* end if */
 
@@ -297,8 +320,18 @@ H5HF_iblock_decr(H5HF_indirect_t *iblock)
                 iblock->par_entry = 0;
             } /* end if */
 
+	    /* Mark indirect block for removal from the metadata cache */
+	    expunge_iblock = TRUE;
+        } /* end if */
+
+	/* Unpin the indirect block */
+        if(H5HF_iblock_unpin(iblock) < 0)
+            HGOTO_ERROR(H5E_HEAP, H5E_CANTUNPIN, FAIL, "unable to unpin fractal heap indirect block")
+
+	/* Check for expunging the indirect block from the metadata cache */
+	if(expunge_iblock) {
             /* Evict the indirect block from the metadata cache */
-            if(H5AC_expunge_entry(iblock->hdr->f, H5AC_dxpl_id, H5AC_FHEAP_IBLOCK, iblock->addr, H5AC__FREE_FILE_SPACE_FLAG) < 0)
+            if(H5AC_expunge_entry(hdr->f, H5AC_dxpl_id, H5AC_FHEAP_IBLOCK, iblock_addr, H5AC__FREE_FILE_SPACE_FLAG) < 0)
                 HGOTO_ERROR(H5E_HEAP, H5E_CANTREMOVE, FAIL, "unable to remove indirect block from cache")
         } /* end if */
     } /* end if */
@@ -420,6 +453,10 @@ H5HF_man_iblock_root_create(H5HF_hdr_t *hdr, hid_t dxpl_id, size_t min_dblock_si
             hdr->pline_root_direct_filter_mask = 0;
         } /* end if */
 
+        /* Scan free space sections to set any 'parent' pointers to new indirect block */
+        if(H5HF_space_create_root(hdr, dxpl_id, iblock) < 0)
+            HGOTO_ERROR(H5E_HEAP, H5E_CANTSET, FAIL, "can't set free space section info to new root indirect block")
+
         /* Unlock first (previously the root) direct block */
         if(H5AC_unprotect(hdr->f, dxpl_id, H5AC_FHEAP_DBLOCK, hdr->man_dtable.table_addr, dblock, H5AC__NO_FLAGS_SET) < 0)
             HGOTO_ERROR(H5E_HEAP, H5E_CANTUNPROTECT, FAIL, "unable to release fractal heap direct block")
@@ -859,6 +896,11 @@ H5HF_man_iblock_root_revert(H5HF_indirect_t *root_iblock, hid_t dxpl_id)
     if(H5HF_hdr_adjust_heap(hdr, (hsize_t)hdr->man_dtable.cparam.start_block_size, (hssize_t)hdr->man_dtable.row_tot_dblock_free[0]) < 0)
         HGOTO_ERROR(H5E_HEAP, H5E_CANTEXTEND, FAIL, "can't increase space to cover root direct block")
 
+    /* Scan free space sections to reset any 'parent' pointers */
+    if(H5HF_space_revert_root(hdr, dxpl_id) < 0)
+        HGOTO_ERROR(H5E_HEAP, H5E_CANTRESET, FAIL, "can't reset free space section info")
+
+
 done:
     if(dblock && H5AC_unprotect(hdr->f, dxpl_id, H5AC_FHEAP_DBLOCK, dblock_addr, dblock, H5AC__NO_FLAGS_SET) < 0)
         HDONE_ERROR(H5E_HEAP, H5E_CANTUNPROTECT, FAIL, "unable to release fractal heap direct block")
@@ -1126,11 +1168,20 @@ H5HF_man_iblock_protect(H5HF_hdr_t *hdr, hid_t dxpl_id, haddr_t iblock_addr,
         else {
             /* Check for root indirect block */
             if(H5F_addr_eq(iblock_addr, hdr->man_dtable.table_addr)) {
-                /* Check for pointer to pinned indirect block in root */
-                if(hdr->root_iblock)
+                /* Check for valid pointer to pinned indirect block in root */
+                if(H5HF_ROOT_IBLOCK_PINNED == hdr->root_iblock_flags) {
+                    /* Sanity check */
+                    HDassert(NULL != hdr->root_iblock);
+
+                    /* Return the pointer to the pinned root indirect block */
                     iblock = hdr->root_iblock;
-                else
+                } /* end if */
+                else {
+                    /* Sanity check */
+                    HDassert(NULL == hdr->root_iblock);
+
                     should_protect = TRUE;
+                } /* end else */
             } /* end if */
             else
                 should_protect = TRUE;
@@ -1158,6 +1209,21 @@ H5HF_man_iblock_protect(H5HF_hdr_t *hdr, hid_t dxpl_id, haddr_t iblock_addr,
         /* Set the indirect block's address */
         iblock->addr = iblock_addr;
 
+        /* Check for root indirect block */
+        if(iblock->block_off == 0) {
+            /* Sanity check - shouldn't be recursively protecting root indirect block */
+            HDassert(0 == (hdr->root_iblock_flags & H5HF_ROOT_IBLOCK_PROTECTED));
+
+            /* Check if we should set the root iblock pointer */
+            if(0 == hdr->root_iblock_flags) {
+                HDassert(NULL == hdr->root_iblock);
+                hdr->root_iblock = iblock;
+            } /* end if */
+
+            /* Indicate that the root indirect block is protected */
+            hdr->root_iblock_flags |= H5HF_ROOT_IBLOCK_PROTECTED;
+        } /* end if */
+
         /* Indicate that the indirect block was protected */
         *did_protect = TRUE;
     } /* end if */
@@ -1202,6 +1268,21 @@ H5HF_man_iblock_unprotect(H5HF_indirect_t *iblock, hid_t dxpl_id,
     /* Check if we previously protected this indirect block */
     /* (as opposed to using an existing pointer to a pinned child indirect block) */
     if(did_protect) {
+        /* Check for root indirect block */
+        if(iblock->block_off == 0) {
+            /* Sanity check - shouldn't be recursively unprotecting root indirect block */
+            HDassert(iblock->hdr->root_iblock_flags & H5HF_ROOT_IBLOCK_PROTECTED);
+
+            /* Check if we should reset the root iblock pointer */
+            if(H5HF_ROOT_IBLOCK_PROTECTED == iblock->hdr->root_iblock_flags) {
+                HDassert(NULL != iblock->hdr->root_iblock);
+                iblock->hdr->root_iblock = NULL;
+            } /* end if */
+
+            /* Indicate that the root indirect block is unprotected */
+            iblock->hdr->root_iblock_flags &= ~(H5HF_ROOT_IBLOCK_PROTECTED);
+        } /* end if */
+
         /* Unprotect the indirect block */
         if(H5AC_unprotect(iblock->hdr->f, dxpl_id, H5AC_FHEAP_IBLOCK, iblock->addr, iblock, cache_flags) < 0)
             HGOTO_ERROR(H5E_HEAP, H5E_CANTUNPROTECT, FAIL, "unable to release fractal heap indirect block")
@@ -1215,7 +1296,7 @@ done:
 /*-------------------------------------------------------------------------
  * Function:	H5HF_man_iblock_attach
  *
- * Purpose:	Attach a block to an indirect block
+ * Purpose:	Attach a child block (direct or indirect) to an indirect block
  *
  * Return:	SUCCEED/FAIL
  *
@@ -1243,7 +1324,7 @@ H5HF_man_iblock_attach(H5HF_indirect_t *iblock, unsigned entry, haddr_t child_ad
     if(H5HF_iblock_incr(iblock) < 0)
         HGOTO_ERROR(H5E_HEAP, H5E_CANTINC, FAIL, "can't increment reference count on shared indirect block")
 
-    /* Point at the direct block */
+    /* Point at the child block */
     iblock->ents[entry].addr = child_addr;
 
     /* Check for I/O filters on this heap */
@@ -1280,7 +1361,7 @@ done:
 /*-------------------------------------------------------------------------
  * Function:	H5HF_man_iblock_detach
  *
- * Purpose:	Detach a block from an indirect block
+ * Purpose:	Detach a child block (direct or indirect) from an indirect block
  *
  * Return:	SUCCEED/FAIL
  *
@@ -1293,6 +1374,7 @@ done:
 herr_t
 H5HF_man_iblock_detach(H5HF_indirect_t *iblock, hid_t dxpl_id, unsigned entry)
 {
+    unsigned row;                       /* Row for entry */
     herr_t ret_value = SUCCEED;         /* Return value */
 
     FUNC_ENTER_NOAPI_NOINIT
@@ -1306,16 +1388,14 @@ H5HF_man_iblock_detach(H5HF_indirect_t *iblock, hid_t dxpl_id, unsigned entry)
     /* Reset address of entry */
     iblock->ents[entry].addr = HADDR_UNDEF;
 
+    /* Compute row for entry */
+    row = entry / iblock->hdr->man_dtable.cparam.width;
+
     /* Check for I/O filters on this heap */
     if(iblock->hdr->filter_len > 0) {
-        unsigned row;           /* Row for entry */
-
         /* Sanity check */
         HDassert(iblock->filt_ents);
 
-        /* Compute row for entry */
-        row = entry / iblock->hdr->man_dtable.cparam.width;
-
         /* If this is a direct block, reset its initial size */
         if(row < iblock->hdr->man_dtable.max_direct_rows) {
             iblock->filt_ents[entry].size = 0;
@@ -1323,6 +1403,24 @@ H5HF_man_iblock_detach(H5HF_indirect_t *iblock, hid_t dxpl_id, unsigned entry)
         } /* end if */
     } /* end if */
 
+    /* Check for indirect block being detached */
+    if(row >= iblock->hdr->man_dtable.max_direct_rows) {
+        unsigned indir_idx;             /* Index in parent's child iblock pointer array */
+
+        /* Sanity check */
+        HDassert(iblock->child_iblocks);
+
+        /* Compute index in child iblock pointer array */
+        indir_idx = entry - (iblock->hdr->man_dtable.max_direct_rows
+                * iblock->hdr->man_dtable.cparam.width);
+
+        /* Sanity check */
+        HDassert(iblock->child_iblocks[indir_idx]);
+
+        /* Reset pointer to child indirect block in parent */
+        iblock->child_iblocks[indir_idx] = NULL;
+    } /* end if */
+
     /* Decrement the # of child blocks */
     /* (If the number of children drop to 0, the indirect block will be
      *  removed from the heap when its ref. count drops to zero and the
diff --git a/src/H5HFpkg.h b/src/H5HFpkg.h
index 2746302..498c45e 100644
--- a/src/H5HFpkg.h
+++ b/src/H5HFpkg.h
@@ -174,6 +174,11 @@
 #define H5HF_OP_MODIFY          0x0001          /* Operation will modify object */
 #define H5HF_OP_FLAGS           (H5HF_OP_MODIFY)        /* Bit-wise OR of all op flags */
 
+/* Flags for 'root_iblock_flags' field in header */
+#define H5HF_ROOT_IBLOCK_PINNED         0x01
+#define H5HF_ROOT_IBLOCK_PROTECTED      0x02
+
+
 /****************************/
 /* Package Private Typedefs */
 /****************************/
@@ -342,7 +347,8 @@ typedef struct H5HF_hdr_t {
     hbool_t     pending_delete; /* Heap is pending deletion */
     uint8_t     sizeof_size;    /* Size of file sizes */
     uint8_t     sizeof_addr;    /* Size of file addresses */
-    struct H5HF_indirect_t *root_iblock;    /* Pointer to pinned root indirect block */
+    struct H5HF_indirect_t *root_iblock;    /* Pointer to root indirect block */
+    unsigned    root_iblock_flags;      /* Flags to indicate whether root indirect block is pinned/protected */
     H5FS_t      *fspace;        /* Free space list for objects in heap */
     H5HF_block_iter_t next_block;   /* Block iterator for searching for next block with space */
     H5B2_t      *huge_bt2;      /* v2 B-tree handle for huge objects */
@@ -457,14 +463,14 @@ typedef struct H5HF_huge_bt2_filt_dir_rec_t {
 typedef struct {
     H5HF_hdr_t *hdr;            /* Fractal heap header */
     hid_t dxpl_id;              /* DXPL ID for operation */
-} H5HF_sect_add_ud1_t;
+} H5HF_sect_add_ud_t;
 
 /* User data for v2 B-tree 'remove' callback on 'huge' objects */
 typedef struct {
     H5HF_hdr_t *hdr;            /* Fractal heap header (in) */
     hid_t dxpl_id;              /* DXPL ID for operation (in) */
     hsize_t obj_len;            /* Length of object removed (out) */
-} H5HF_huge_remove_ud1_t;
+} H5HF_huge_remove_ud_t;
 
 /* User data for fractal heap header cache client callback */
 typedef struct H5HF_hdr_cache_ud_t {
@@ -701,10 +707,14 @@ H5_DLL herr_t H5HF_tiny_op(H5HF_hdr_t *hdr, const uint8_t *id,
 H5_DLL herr_t H5HF_tiny_remove(H5HF_hdr_t *fh, const uint8_t *id);
 
 /* Debugging routines for dumping file structures */
+H5_DLL void H5HF_hdr_print(const H5HF_hdr_t *hdr, hid_t dxpl_id,
+	hbool_t dump_internal, FILE *stream, int indent, int fwidth);
 H5_DLL herr_t H5HF_hdr_debug(H5F_t *f, hid_t dxpl_id, haddr_t addr,
     FILE *stream, int indent, int fwidth);
 H5_DLL herr_t H5HF_dblock_debug(H5F_t *f, hid_t dxpl_id, haddr_t addr,
     FILE *stream, int indent, int fwidth, haddr_t hdr_addr, size_t nrec);
+H5_DLL void H5HF_iblock_print(const H5HF_indirect_t *iblock, hbool_t dump_internal,
+    FILE *stream, int indent, int fwidth);
 H5_DLL herr_t H5HF_iblock_debug(H5F_t *f, hid_t dxpl_id, haddr_t addr,
     FILE *stream, int indent, int fwidth, haddr_t hdr_addr, unsigned nrows);
 
@@ -733,6 +743,9 @@ H5_DLL herr_t H5HF_space_add(H5HF_hdr_t *hdr, hid_t dxpl_id,
     H5HF_free_section_t *node, unsigned flags);
 H5_DLL htri_t H5HF_space_find(H5HF_hdr_t *hdr, hid_t dxpl_id, hsize_t request,
     H5HF_free_section_t **node);
+H5_DLL herr_t H5HF_space_revert_root(const H5HF_hdr_t *hdr, hid_t dxpl_id);
+H5_DLL herr_t H5HF_space_create_root(const H5HF_hdr_t *hdr, hid_t dxpl_id,
+    H5HF_indirect_t *root_iblock);
 H5_DLL herr_t H5HF_space_size(H5HF_hdr_t *hdr, hid_t dxpl_id, hsize_t *fs_size);
 H5_DLL herr_t H5HF_space_remove(H5HF_hdr_t *hdr, hid_t dxpl_id,
     H5HF_free_section_t *node);
diff --git a/src/H5HFsection.c b/src/H5HFsection.c
index 38d9381..87fa069 100644
--- a/src/H5HFsection.c
+++ b/src/H5HFsection.c
@@ -665,42 +665,6 @@ H5HF_sect_single_dblock_info(H5HF_hdr_t *hdr, hid_t dxpl_id,
     HDassert(dblock_addr);
     HDassert(dblock_size);
 
-    /* Check for section in first direct block of heap */
-    if(sect->sect_info.addr < hdr->man_dtable.cparam.start_block_size) {
-        /* Check for heap changing from direct <-> indirect root (or vice versa)
-         *      while section was live.
-         */
-        if(sect->u.single.parent) {
-            /* Check for heap converting from indirect root to direct root while section was live */
-            if(hdr->man_dtable.curr_root_rows == 0) {
-                /* Release hold on parent indirect block */
-                if(H5HF_iblock_decr(sect->u.single.parent) < 0)
-                    HGOTO_ERROR(H5E_HEAP, H5E_CANTDEC, FAIL, "can't decrement reference count on section's indirect block")
-
-                /* Reset parent information */
-                sect->u.single.parent = NULL;
-                sect->u.single.par_entry = 0;
-            } /* end if */
-            else {
-                /* Check for heap converting from indirect to direct and back
-                 *      to indirect again, which would indicate a different
-                 *      indirect root block would be used for the parent of
-                 *      this section and the actual root indirect block.
-                 */
-                if(H5HF_sect_single_locate_parent(hdr, dxpl_id, TRUE, sect) < 0)
-                    HGOTO_ERROR(H5E_HEAP, H5E_CANTGET, FAIL, "can't get section's parent info")
-            } /* end else */
-        } /* end if */
-        else {
-            /* Check for heap converting from direct root to indirect root while section was live */
-            if(hdr->man_dtable.curr_root_rows != 0) {
-                /* Look up indirect block information for section */
-                if(H5HF_sect_single_locate_parent(hdr, dxpl_id, FALSE, sect) < 0)
-                    HGOTO_ERROR(H5E_HEAP, H5E_CANTGET, FAIL, "can't get section's parent info")
-            } /* end if */
-        } /* end else */
-    } /* end if */
-
     /* Check for root direct block */
     if(hdr->man_dtable.curr_root_rows == 0) {
         /* Retrieve direct block info from heap header */
@@ -860,7 +824,7 @@ H5HF_sect_single_add(H5FS_section_info_t *_sect, unsigned *flags, void *_udata)
      */
     if(!(*flags & H5FS_ADD_DESERIALIZING)) {
         H5HF_free_section_t *sect = (H5HF_free_section_t *)_sect;   /* Fractal heap free section */
-        H5HF_sect_add_ud1_t *udata = (H5HF_sect_add_ud1_t *)_udata;   /* User callback data */
+        H5HF_sect_add_ud_t *udata = (H5HF_sect_add_ud_t *)_udata;   /* User callback data */
         H5HF_hdr_t *hdr = udata->hdr;       /* Fractal heap header */
         hid_t dxpl_id = udata->dxpl_id;     /* DXPL ID for operation */
 
@@ -992,7 +956,7 @@ H5HF_sect_single_merge(H5FS_section_info_t *_sect1, H5FS_section_info_t *_sect2,
 {
     H5HF_free_section_t *sect1 = (H5HF_free_section_t *)_sect1;   /* Fractal heap free section */
     H5HF_free_section_t *sect2 = (H5HF_free_section_t *)_sect2;   /* Fractal heap free section */
-    H5HF_sect_add_ud1_t *udata = (H5HF_sect_add_ud1_t *)_udata;   /* User callback data */
+    H5HF_sect_add_ud_t *udata = (H5HF_sect_add_ud_t *)_udata;   /* User callback data */
     H5HF_hdr_t *hdr = udata->hdr;       /* Fractal heap header */
     hid_t dxpl_id = udata->dxpl_id;     /* DXPL ID for operation */
     herr_t ret_value = SUCCEED;         /* Return value */
@@ -1050,7 +1014,7 @@ static htri_t
 H5HF_sect_single_can_shrink(const H5FS_section_info_t *_sect, void *_udata)
 {
     const H5HF_free_section_t *sect = (const H5HF_free_section_t *)_sect;   /* Fractal heap free section */
-    H5HF_sect_add_ud1_t *udata = (H5HF_sect_add_ud1_t *)_udata;   /* User callback data */
+    H5HF_sect_add_ud_t *udata = (H5HF_sect_add_ud_t *)_udata;   /* User callback data */
     H5HF_hdr_t *hdr = udata->hdr;       /* Fractal heap header */
     htri_t ret_value = FALSE;           /* Return value */
 
@@ -1105,7 +1069,7 @@ static herr_t
 H5HF_sect_single_shrink(H5FS_section_info_t **_sect, void UNUSED *_udata)
 {
     H5HF_free_section_t **sect = (H5HF_free_section_t **)_sect;   /* Fractal heap free section */
-    H5HF_sect_add_ud1_t *udata = (H5HF_sect_add_ud1_t *)_udata;   /* User callback data */
+    H5HF_sect_add_ud_t *udata = (H5HF_sect_add_ud_t *)_udata;   /* User callback data */
     H5HF_hdr_t *hdr = udata->hdr;       /* Fractal heap header */
     hid_t dxpl_id = udata->dxpl_id;     /* DXPL ID for operation */
     H5HF_direct_t *dblock;              /* Pointer to direct block for section */
@@ -1814,7 +1778,7 @@ H5HF_sect_row_merge(H5FS_section_info_t *_sect1, H5FS_section_info_t *_sect2,
 {
     H5HF_free_section_t *sect1 = (H5HF_free_section_t *)_sect1;   /* Fractal heap free section */
     H5HF_free_section_t *sect2 = (H5HF_free_section_t *)_sect2;   /* Fractal heap free section */
-    H5HF_sect_add_ud1_t *udata = (H5HF_sect_add_ud1_t *)_udata;   /* User callback data */
+    H5HF_sect_add_ud_t *udata = (H5HF_sect_add_ud_t *)_udata;   /* User callback data */
     H5HF_hdr_t *hdr = udata->hdr;       /* Fractal heap header */
     hid_t dxpl_id = udata->dxpl_id;     /* DXPL ID for operation */
     herr_t ret_value = SUCCEED;         /* Return value */
@@ -1881,7 +1845,7 @@ static htri_t
 H5HF_sect_row_can_shrink(const H5FS_section_info_t *_sect, void UNUSED *_udata)
 {
     const H5HF_free_section_t *sect = (const H5HF_free_section_t *)_sect;   /* Fractal heap free section */
-    H5HF_sect_add_ud1_t *udata = (H5HF_sect_add_ud1_t *)_udata;   /* User callback data */
+    H5HF_sect_add_ud_t *udata = (H5HF_sect_add_ud_t *)_udata;   /* User callback data */
     H5HF_hdr_t *hdr = udata->hdr;       /* Fractal heap header */
     htri_t ret_value = FALSE;           /* Return value */
 
@@ -1919,7 +1883,7 @@ H5HF_sect_row_shrink(H5FS_section_info_t **_sect, void *_udata)
 {
     H5HF_free_section_t **sect = (H5HF_free_section_t **)_sect;   /* Fractal heap free section */
     H5HF_free_section_t *top_indir_sect; /* Top indirect section for row */
-    H5HF_sect_add_ud1_t *udata = (H5HF_sect_add_ud1_t *)_udata;   /* User callback data */
+    H5HF_sect_add_ud_t *udata = (H5HF_sect_add_ud_t *)_udata;   /* User callback data */
     H5HF_hdr_t *hdr = udata->hdr;       /* Fractal heap header */
     hid_t dxpl_id = udata->dxpl_id;     /* DXPL ID for operation */
     herr_t ret_value = SUCCEED;         /* Return value */
@@ -2161,7 +2125,7 @@ H5HF_sect_indirect_iblock_off(const H5HF_free_section_t *sect)
  *
  * Purpose:	Get the "top" indirect section
  *
- * Return:	Pointer to the top indirect sectin (can't fail)
+ * Return:	Pointer to the top indirect section (can't fail)
  *
  * Programmer:	Quincey Koziol
  *		koziol@ncsa.uiuc.edu
diff --git a/src/H5HFspace.c b/src/H5HFspace.c
index cec9b3a..01330d3 100644
--- a/src/H5HFspace.c
+++ b/src/H5HFspace.c
@@ -168,7 +168,7 @@ herr_t
 H5HF_space_add(H5HF_hdr_t *hdr, hid_t dxpl_id, H5HF_free_section_t *node,
     unsigned flags)
 {
-    H5HF_sect_add_ud1_t udata;          /* User data for free space manager 'add' */
+    H5HF_sect_add_ud_t udata;          /* User data for free space manager 'add' */
     herr_t ret_value = SUCCEED;         /* Return value */
 
     FUNC_ENTER_NOAPI_NOINIT
@@ -246,6 +246,185 @@ done:
 
 
 /*-------------------------------------------------------------------------
+ * Function:	H5HF_space_revert_root_cb
+ *
+ * Purpose:	Callback routine from iterator, to reset 'parent' pointers in
+ *		sections, when the heap is changing from having a root indirect
+ *		block to a direct block.
+ *
+ * Return:	Success:	non-negative
+ *		Failure:	negative
+ *
+ * Programmer:	Quincey Koziol
+ *		koziol@hdfgroup.org
+ *		Feb 24 2012
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+H5HF_space_revert_root_cb(H5FS_section_info_t *_sect, void UNUSED *_udata)
+{
+    H5HF_free_section_t *sect = (H5HF_free_section_t *)_sect;       /* Section to dump info */
+    herr_t      ret_value = SUCCEED;    /* Return value */
+
+    FUNC_ENTER_NOAPI_NOINIT
+
+    /*
+     * Check arguments.
+     */
+    HDassert(sect);
+
+    /* Only modify "live" single blocks... */
+    if(sect->sect_info.type == H5HF_FSPACE_SECT_SINGLE && sect->sect_info.state == H5FS_SECT_LIVE) {
+        /* Release hold on previous indirect block (we must have one) */
+        HDassert(sect->u.single.parent);
+        if(H5HF_iblock_decr(sect->u.single.parent) < 0)
+            HGOTO_ERROR(H5E_HEAP, H5E_CANTDEC, FAIL, "can't decrement reference count on section's indirect block")
+
+        /* Reset parent information */
+        sect->u.single.parent = NULL;
+        sect->u.single.par_entry = 0;
+    } /* end if */
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5HF_space_revert_root_cb() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:	H5HF_space_revert_root
+ *
+ * Purpose:	Reset 'parent' pointers in sections, when the heap is
+ *		changing from having a root indirect block to a direct block.
+ *
+ * Return:	Success:	non-negative
+ *		Failure:	negative
+ *
+ * Programmer:	Quincey Koziol
+ *		koziol@hdfgroup.org
+ *		Feb 23 2012
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5HF_space_revert_root(const H5HF_hdr_t *hdr, hid_t dxpl_id)
+{
+    herr_t ret_value = SUCCEED;         /* Return value */
+
+    FUNC_ENTER_NOAPI_NOINIT
+
+    /*
+     * Check arguments.
+     */
+    HDassert(hdr);
+
+    /* Only need to scan the sections if the free space has been initialized */
+    if(hdr->fspace) {
+	/* Iterate over all sections, reseting the parent pointers in 'single' sections */
+        if(H5FS_sect_iterate(hdr->f, dxpl_id, hdr->fspace, H5HF_space_revert_root_cb, NULL) < 0)
+            HGOTO_ERROR(H5E_FSPACE, H5E_BADITER, FAIL, "can't iterate over sections to reset parent pointers")
+    } /* end if */
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5HF_space_revert_root() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:	H5HF_space_create_root_cb
+ *
+ * Purpose:	Callback routine from iterator, to set 'parent' pointers in
+ *		sections to newly created root indirect block, when the heap
+ *		is changing from having a root direct block to an indirect block.
+ *
+ * Return:	Success:	non-negative
+ *		Failure:	negative
+ *
+ * Programmer:	Quincey Koziol
+ *		koziol@hdfgroup.org
+ *		Feb 24 2012
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+H5HF_space_create_root_cb(H5FS_section_info_t *_sect, void *_udata)
+{
+    H5HF_free_section_t *sect = (H5HF_free_section_t *)_sect;       /* Section to dump info */
+    H5HF_indirect_t *root_iblock = (H5HF_indirect_t *)_udata;	/* User data for callback */
+    herr_t      ret_value = SUCCEED;    /* Return value */
+
+    FUNC_ENTER_NOAPI_NOINIT
+
+    /*
+     * Check arguments.
+     */
+    HDassert(sect);
+    HDassert(root_iblock);
+
+    /* Sanity check sections */
+    /* (If we are switching from a direct block for the root block of the heap, */
+    /*	there should only be 'single' type sections. -QAK) */
+    HDassert(sect->sect_info.type == H5HF_FSPACE_SECT_SINGLE);
+
+    /* Increment ref. count on new root indirect block */
+    if(H5HF_iblock_incr(root_iblock) < 0)
+        HGOTO_ERROR(H5E_HEAP, H5E_CANTINC, FAIL, "can't increment reference count on section's indirect block")
+
+    /* Set parent info ("live" section must _NOT_ have a parent right now) */
+    if(sect->sect_info.state == H5FS_SECT_SERIALIZED)
+        sect->sect_info.state = H5FS_SECT_LIVE;         /* Mark "live" now */
+    else
+         HDassert(!sect->u.single.parent);
+    sect->u.single.parent = root_iblock;
+    sect->u.single.par_entry = 0;
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5HF_space_create_root_cb() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:	H5HF_space_create_root
+ *
+ * Purpose:	Set 'parent' pointers in sections to new indirect block, when
+ *		the heap is changing from having a root direct block to a
+ *		indirect block.
+ *
+ * Return:	Success:	non-negative
+ *		Failure:	negative
+ *
+ * Programmer:	Quincey Koziol
+ *		koziol@hdfgroup.org
+ *		Feb 24 2012
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5HF_space_create_root(const H5HF_hdr_t *hdr, hid_t dxpl_id, H5HF_indirect_t *root_iblock)
+{
+    herr_t ret_value = SUCCEED;         /* Return value */
+
+    FUNC_ENTER_NOAPI_NOINIT
+
+    /*
+     * Check arguments.
+     */
+    HDassert(hdr);
+    HDassert(root_iblock);
+
+    /* Only need to scan the sections if the free space has been initialized */
+    if(hdr->fspace) {
+	/* Iterate over all sections, seting the parent pointers in 'single' sections to the new indirect block */
+        if(H5FS_sect_iterate(hdr->f, dxpl_id, hdr->fspace, H5HF_space_create_root_cb, root_iblock) < 0)
+            HGOTO_ERROR(H5E_FSPACE, H5E_BADITER, FAIL, "can't iterate over sections to set parent pointers")
+    } /* end if */
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5HF_space_create_root() */
+
+
+/*-------------------------------------------------------------------------
  * Function:	H5HF_space_size
  *
  * Purpose:	Query the size of the heap's free space info on disk
diff --git a/src/H5I.c b/src/H5I.c
index 617b7a4..7b33533 100644
--- a/src/H5I.c
+++ b/src/H5I.c
@@ -109,6 +109,11 @@ typedef struct {
     H5I_id_info_t **id_list;	/*pointer to an array of ptrs to IDs	    */
 } H5I_id_type_t;
 
+typedef struct {
+    H5I_search_func_t app_cb;   /* Application's callback routine */
+    void *app_key;              /* Application's "key" (user data) */
+    void *ret_obj;              /* Object to return */
+} H5I_search_ud_t;
 
 /*-------------------- Locally scoped variables -----------------------------*/
 
@@ -128,6 +133,7 @@ H5FL_DEFINE_STATIC(H5I_id_info_t);
 
 /*--------------------- Local function prototypes ---------------------------*/
 static H5I_id_info_t *H5I_find_id(hid_t id);
+static int H5I_search_cb(void *obj, hid_t id, void *udata);
 #ifdef H5I_DEBUG_OUTPUT
 static herr_t H5I_debug(H5I_type_t type);
 #endif /* H5I_DEBUG_OUTPUT */
@@ -1921,6 +1927,40 @@ done:
 
 
 /*-------------------------------------------------------------------------
+ * Function:	H5I_search_cb
+ *
+ * Purpose:	Callback routine for H5Isearch, when it calls H5I_iterate.
+ *		Calls "user" callback search function, and then sets return
+ *		value, based on the result of that callback.
+ *
+ * Return:	Success:	The first object in the type for which FUNC
+ *				returns non-zero. NULL if FUNC returned zero
+ *				for every object in the type.
+ *		Failure:	NULL
+ *
+ * Programmer:	Quincey Koziol
+ *		Friday, March 30, 2012
+ *
+ *-------------------------------------------------------------------------
+ */
+static int
+H5I_search_cb(void *obj, hid_t id, void *_udata)
+{
+    H5I_search_ud_t *udata = (H5I_search_ud_t *)_udata; /* User data for callback */
+    int ret_value;     /* Callback return value */
+
+    FUNC_ENTER_NOAPI_NOINIT
+
+    ret_value = (*udata->app_cb)(obj, id, udata->app_key);
+    if(ret_value > 0)
+        udata->ret_obj = obj;
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5I_search_cb() */
+
+
+/*-------------------------------------------------------------------------
  * Function:	H5Isearch
  *
  * Purpose:	Apply function FUNC to each member of type TYPE and return a
@@ -1947,14 +1987,27 @@ done:
 void *
 H5Isearch(H5I_type_t type, H5I_search_func_t func, void *key)
 {
-    void * ret_value;                      /* Return value */
+    H5I_search_ud_t udata;      /* Context for iteration */
+    void *ret_value;            /* Return value */
 
     FUNC_ENTER_API(NULL)
 
+    /* Check arguments */
     if(H5I_IS_LIB_TYPE(type))
         HGOTO_ERROR(H5E_ATOM, H5E_BADGROUP, NULL, "cannot call public function on library type")
 
-    ret_value = H5I_search(type, func, key, TRUE);
+    /* Set up udata struct */
+    udata.app_cb = func;
+    udata.app_key = key;
+    udata.ret_obj = NULL;
+
+    /* Note that H5I_iterate returns an error code.  We ignore it 
+     * here, as we can't do anything with it without revising the API.
+     */
+    H5I_iterate(type, H5I_search_cb, &udata, TRUE);
+
+    /* Set return value */
+    ret_value = udata.ret_obj;
 
 done:
     FUNC_LEAVE_API(ret_value)
@@ -1962,64 +2015,72 @@ done:
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5I_search
+ * Function:	H5I_iterate
  *
- * Purpose:	Apply function FUNC to each member of type TYPE and return a
- *		pointer to the first object for which FUNC returns non-zero.
- *		The FUNC should take a pointer to the object and the KEY as
- *		arguments and return non-zero to terminate the search (zero
- *		to continue).
+ * Purpose:	Apply function FUNC to each member of type TYPE (with 
+ *		non-zero application reference count if app_ref is TRUE).  
+ *		Stop if FUNC returns a non zero value (i.e. anything 
+ *		other than H5_ITER_CONT).  
  *
- * Limitation:	Currently there is no way to start searching from where a
- *		previous search left off.
+ *		If FUNC returns a positive value (i.e. H5_ITER_STOP), 
+ *		return SUCCEED.
  *
- * Return:	Success:	The first object in the type for which FUNC
- *				returns non-zero. NULL if FUNC returned zero
- *				for every object in the type.
- *		Failure:	NULL
+ *		If FUNC returns a negative value (i.e. H5_ITER_ERROR), 
+ *		return FAIL.
+ *		
+ *		The FUNC should take a pointer to the object and the 
+ *		udata as arguments and return non-zero to terminate 
+ *		siteration, and zero to continue.
  *
- * Programmer:	Robb Matzke
- *		Friday, February 19, 1999
+ * Limitation:	Currently there is no way to start the iteration from 
+ *		where a previous iteration left off.
  *
- * Modifications:  Neil Fortner
- *      Wednesday, October 1, 2008
- *      Added app_ref parameter.  When set to TRUE, the function will only
- *      operate on ids that have a nonzero application reference count.
+ * Return:	Success:	SUCCEED
+ *		Failure:	FAIL
+ *
+ * Programmer:	John Mainzer
+ *		Monday, December 6, 2011
  *
  *-------------------------------------------------------------------------
  */
-void *
-H5I_search(H5I_type_t type, H5I_search_func_t func, void *key, hbool_t app_ref)
+herr_t
+H5I_iterate(H5I_type_t type, H5I_search_func_t func, void *udata, hbool_t app_ref)
 {
-    H5I_id_type_t	*type_ptr;	/*ptr to the type	*/
-    void		*ret_value = NULL;	/*return value		*/
+    H5I_id_type_t *type_ptr;		/*ptr to the type	*/
+    herr_t	   ret_value = SUCCEED;	/*return value		*/
+
+    FUNC_ENTER_NOAPI(FAIL)
 
-    FUNC_ENTER_NOAPI(NULL
-)
     /* Check arguments */
     if(type <= H5I_BADID || type >= H5I_next_type)
-	HGOTO_ERROR(H5E_ARGS, H5E_BADRANGE, NULL, "invalid type number")
+	HGOTO_ERROR(H5E_ARGS, H5E_BADRANGE, FAIL, "invalid type number")
 
     type_ptr = H5I_id_type_list_g[type];
 
-    if(type_ptr == NULL || type_ptr->count <= 0)
-	HGOTO_ERROR(H5E_ATOM, H5E_BADGROUP, NULL, "invalid type")
-
-    /* Only iterate through hash table if there are IDs in group */
-    if(type_ptr->ids > 0) {
-        H5I_id_info_t	*id_ptr;	/*ptr to the new ID	*/
-        H5I_id_info_t	*next_id;	/*ptr to the next ID	*/
-        unsigned i;			/*counter		*/
+    /* Only iterate through hash table if it is initialized and there are IDs in group */
+    if(type_ptr && type_ptr->count > 0 && type_ptr->ids > 0) {
+        unsigned u;			/* Counter		*/
 
         /* Start at the beginning of the array */
-        for(i = 0; i < type_ptr->hash_size; i++) {
-            id_ptr = type_ptr->id_list[i];
+        for(u = 0; u < type_ptr->hash_size; u++) {
+            H5I_id_info_t	*id_ptr;	/* Ptr to the new ID	*/
+
+            id_ptr = type_ptr->id_list[u];
             while(id_ptr) {
-                next_id = id_ptr->next;      /* Protect against ID being deleted in callback */
-                /* (Casting away const OK -QAK) */
-                if((!app_ref || id_ptr->app_count) && (*func)((void *)id_ptr->obj_ptr, id_ptr->id, key))
-                    /* (Casting away const OK -QAK) */
-                    HGOTO_DONE((void *)id_ptr->obj_ptr);	/*found the item*/
+                H5I_id_info_t	*next_id;	/* Ptr to the next ID	*/
+
+                /* Protect against ID being deleted in callback */
+                next_id = id_ptr->next;
+                if((!app_ref) || (id_ptr->app_count > 0)) {
+                    herr_t cb_ret_val;  /* Callback return value */
+
+                    /* (Casting away const OK) */
+		    cb_ret_val = (*func)((void *)id_ptr->obj_ptr, id_ptr->id, udata);
+		    if(cb_ret_val > 0)
+                        HGOTO_DONE(SUCCEED)	/* terminate iteration early */
+		    else if(cb_ret_val < 0)
+			HGOTO_ERROR(H5E_ARGS, H5E_BADRANGE, FAIL, "func failed")
+		} /* end if */
                 id_ptr = next_id;
             } /* end while */
         } /* end for */
@@ -2027,7 +2088,7 @@ H5I_search(H5I_type_t type, H5I_search_func_t func, void *key, hbool_t app_ref)
 
 done:
     FUNC_LEAVE_NOAPI(ret_value)
-} /* end H5I_search() */
+} /* end H5I_iterate() */
 
 
 /*-------------------------------------------------------------------------
diff --git a/src/H5Iprivate.h b/src/H5Iprivate.h
index 3a9e2db..ee938df 100644
--- a/src/H5Iprivate.h
+++ b/src/H5Iprivate.h
@@ -70,7 +70,7 @@ H5_DLL H5I_type_t H5I_get_type(hid_t id);
 H5_DLL hid_t H5I_get_file_id(hid_t obj_id, hbool_t app_ref);
 H5_DLL void *H5I_remove(hid_t id);
 H5_DLL void *H5I_remove_verify(hid_t id, H5I_type_t id_type);
-H5_DLL void *H5I_search(H5I_type_t type, H5I_search_func_t func, void *key, hbool_t app_ref);
+H5_DLL herr_t H5I_iterate(H5I_type_t type, H5I_search_func_t func, void *udata, hbool_t app_ref);
 H5_DLL int H5I_get_ref(hid_t id, hbool_t app_ref);
 H5_DLL int H5I_inc_ref(hid_t id, hbool_t app_ref);
 H5_DLL int H5I_dec_ref(hid_t id);
diff --git a/src/H5MF.c b/src/H5MF.c
index fce151e..f9ca256 100644
--- a/src/H5MF.c
+++ b/src/H5MF.c
@@ -1172,9 +1172,9 @@ HDfprintf(stderr, "%s: Leaving\n", FUNC);
  *-------------------------------------------------------------------------
  */
 static herr_t
-H5MF_sects_cb(const H5FS_section_info_t *_sect, void *_udata)
+H5MF_sects_cb(H5FS_section_info_t *_sect, void *_udata)
 {
-    const H5MF_free_section_t *sect = (const H5MF_free_section_t *)_sect;
+    H5MF_free_section_t *sect = (H5MF_free_section_t *)_sect;
     H5MF_sect_iter_ud_t *udata = (H5MF_sect_iter_ud_t *)_udata;
 
     FUNC_ENTER_NOAPI_NOINIT_NOERR
diff --git a/src/H5MFdbg.c b/src/H5MFdbg.c
index bdc811f..d6fc5ce 100644
--- a/src/H5MFdbg.c
+++ b/src/H5MFdbg.c
@@ -99,9 +99,9 @@ typedef struct {
  *-------------------------------------------------------------------------
  */
 static herr_t
-H5MF_sects_debug_cb(const H5FS_section_info_t *_sect, void *_udata)
+H5MF_sects_debug_cb(H5FS_section_info_t *_sect, void *_udata)
 {
-    const H5MF_free_section_t *sect = (const H5MF_free_section_t *)_sect;       /* Section to dump info */
+    H5MF_free_section_t *sect = (H5MF_free_section_t *)_sect;       /* Section to dump info */
     H5MF_debug_iter_ud_t *udata = (H5MF_debug_iter_ud_t *)_udata;         /* User data for callbacks */
     herr_t      ret_value = SUCCEED;    /* Return value */
 
diff --git a/src/H5O.c b/src/H5O.c
index 82d9453..ec4cba9 100644
--- a/src/H5O.c
+++ b/src/H5O.c
@@ -79,12 +79,12 @@ typedef struct {
 /********************/
 
 static herr_t H5O_delete_oh(H5F_t *f, hid_t dxpl_id, H5O_t *oh);
-static const H5O_obj_class_t *H5O_obj_class(const H5O_loc_t *loc, hid_t dxpl_id);
 static herr_t H5O_obj_type_real(H5O_t *oh, H5O_type_t *obj_type);
 static herr_t H5O_visit(hid_t loc_id, const char *obj_name, H5_index_t idx_type,
     H5_iter_order_t order, H5O_iterate_t op, void *op_data, hid_t lapl_id,
     hid_t dxpl_id);
 static herr_t H5O_get_hdr_info_real(const H5O_t *oh, H5O_hdr_info_t *hdr);
+static const H5O_obj_class_t *H5O_obj_class_real(H5O_t *oh);
 
 
 /*********************/
@@ -2382,7 +2382,7 @@ H5O_obj_type_real(H5O_t *oh, H5O_type_t *obj_type)
  *
  *-------------------------------------------------------------------------
  */
-static const H5O_obj_class_t *
+const H5O_obj_class_t *
 H5O_obj_class(const H5O_loc_t *loc, hid_t dxpl_id)
 {
     H5O_t	*oh = NULL;                     /* Object header for location */
@@ -2419,7 +2419,7 @@ done:
  *
  *-------------------------------------------------------------------------
  */
-const H5O_obj_class_t *
+static const H5O_obj_class_t *
 H5O_obj_class_real(H5O_t *oh)
 {
     size_t	i;                      /* Local index variable */
diff --git a/src/H5Oainfo.c b/src/H5Oainfo.c
index ff4cc5d..b207ea2 100644
--- a/src/H5Oainfo.c
+++ b/src/H5Oainfo.c
@@ -46,11 +46,11 @@ static herr_t H5O_ainfo_delete(H5F_t *f, hid_t dxpl_id, H5O_t *open_oh,
 static herr_t H5O_ainfo_pre_copy_file(H5F_t *file_src, const void *mesg_src,
     hbool_t *deleted, const H5O_copy_t *cpy_info, void *udata);
 static void *H5O_ainfo_copy_file(H5F_t *file_src, void *mesg_src,
-    H5F_t *file_dst, hbool_t *recompute_size, H5O_copy_t *cpy_info, void *udata,
-    hid_t dxpl_id);
+    H5F_t *file_dst, hbool_t *recompute_size, unsigned *mesg_flags,
+    H5O_copy_t *cpy_info, void *udata, hid_t dxpl_id);
 static herr_t H5O_ainfo_post_copy_file(const H5O_loc_t *src_oloc,
-    const void *mesg_src, H5O_loc_t *dst_oloc, void *mesg_dst, hid_t dxpl_id,
-    H5O_copy_t *cpy_info);
+    const void *mesg_src, H5O_loc_t *dst_oloc, void *mesg_dst,
+    unsigned *mesg_flags, hid_t dxpl_id, H5O_copy_t *cpy_info);
 static herr_t H5O_ainfo_debug(H5F_t *f, hid_t dxpl_id, const void *_mesg,
 			     FILE * stream, int indent, int fwidth);
 
@@ -403,7 +403,8 @@ H5O_ainfo_pre_copy_file(H5F_t UNUSED *file_src, const void UNUSED *native_src,
  */
 static void *
 H5O_ainfo_copy_file(H5F_t *file_src, void *mesg_src, H5F_t *file_dst,
-    hbool_t UNUSED *recompute_size, H5O_copy_t *cpy_info, void UNUSED *udata, hid_t dxpl_id)
+    hbool_t UNUSED *recompute_size, unsigned UNUSED *mesg_flags,
+    H5O_copy_t *cpy_info, void UNUSED *udata, hid_t dxpl_id)
 {
     H5O_ainfo_t *ainfo_src = (H5O_ainfo_t *)mesg_src;
     H5O_ainfo_t *ainfo_dst = NULL;
@@ -468,7 +469,8 @@ done:
  */
 static herr_t
 H5O_ainfo_post_copy_file(const H5O_loc_t *src_oloc, const void *mesg_src,
-    H5O_loc_t *dst_oloc, void *mesg_dst, hid_t dxpl_id, H5O_copy_t *cpy_info)
+    H5O_loc_t *dst_oloc, void *mesg_dst, unsigned UNUSED *mesg_flags,
+    hid_t dxpl_id, H5O_copy_t *cpy_info)
 {
     const H5O_ainfo_t *ainfo_src = (const H5O_ainfo_t *)mesg_src;
     herr_t ret_value = SUCCEED;   /* Return value */
diff --git a/src/H5Oattr.c b/src/H5Oattr.c
index 8cd243b..510d64f 100644
--- a/src/H5Oattr.c
+++ b/src/H5Oattr.c
@@ -61,6 +61,7 @@ static herr_t H5O_attr_debug(H5F_t *f, hid_t dxpl_id, const void *_mesg,
 #define H5O_SHARED_COPY_FILE_REAL	H5O_attr_copy_file
 #define H5O_SHARED_POST_COPY_FILE	H5O_attr_shared_post_copy_file
 #define H5O_SHARED_POST_COPY_FILE_REAL	H5O_attr_post_copy_file
+#undef  H5O_SHARED_POST_COPY_FILE_UPD
 #define H5O_SHARED_DEBUG		H5O_attr_shared_debug
 #define H5O_SHARED_DEBUG_REAL		H5O_attr_debug
 #include "H5Oshared.h"			/* Shared Object Header Message Callbacks */
diff --git a/src/H5Oattribute.c b/src/H5Oattribute.c
index fbfc140..30ec732 100644
--- a/src/H5Oattribute.c
+++ b/src/H5Oattribute.c
@@ -135,9 +135,6 @@ typedef struct {
 /********************/
 /* Local Prototypes */
 /********************/
-static herr_t H5O_attr_iterate_real(hid_t loc_id, const H5O_loc_t *loc,
-    hid_t dxpl_id, H5_index_t idx_type, H5_iter_order_t order, hsize_t skip,
-    hsize_t *last_attr, const H5A_attr_iter_op_t *attr_op, void *op_data);
 static htri_t H5O_attr_find_opened_attr(const H5O_loc_t *loc, H5A_t **attr,
     const char* name_to_open);
 
@@ -437,8 +434,10 @@ H5O_attr_open_cb(H5O_t *oh, H5O_mesg_t *mesg/*in,out*/, unsigned sequence,
         if(NULL == (udata->attr = H5A_copy(NULL, (H5A_t *)mesg->native)))
             HGOTO_ERROR(H5E_ATTR, H5E_CANTCOPY, H5_ITER_ERROR, "unable to copy attribute")
 
-        /* Assign [somewhat arbitrary] creation order value, for older versions of the format */
-        if(oh->version == H5O_VERSION_1)
+        /* Assign [somewhat arbitrary] creation order value, for older versions
+         * of the format or if creation order is not tracked */
+        if(oh->version == H5O_VERSION_1
+                || !(oh->flags & H5O_HDR_ATTR_CRT_ORDER_TRACKED))
             udata->attr->shared->crt_idx = sequence;
 
         /* Stop iterating */
@@ -704,18 +703,23 @@ H5O_attr_find_opened_attr(const H5O_loc_t *loc, H5A_t **attr, const char* name_t
         HGOTO_ERROR(H5E_ATTR, H5E_BADVALUE, FAIL, "can't get file serial number")
 
     /* Count all opened attributes */
-    num_open_attr = H5F_get_obj_count(loc->file, H5F_OBJ_ATTR | H5F_OBJ_LOCAL, FALSE);
+    if(H5F_get_obj_count(loc->file, H5F_OBJ_ATTR | H5F_OBJ_LOCAL, FALSE, &num_open_attr) < 0)
+        HGOTO_ERROR(H5E_ATTR, H5E_CANTGET, FAIL, "can't count opened attributes")
 
     /* Find out whether the attribute has been opened */
     if(num_open_attr) {
+        size_t check_num_attr;  /* Number of open attribute IDs */
         size_t u;          /* Local index variable */
 
         /* Allocate space for the attribute ID list */
         if(NULL == (attr_id_list = (hid_t *)H5MM_malloc(num_open_attr * sizeof(hid_t))))
-            HGOTO_ERROR(H5E_ATTR, H5E_NOSPACE, FAIL, "unable to allocate memory for attribute ID list")
+            HGOTO_ERROR(H5E_ATTR, H5E_CANTALLOC, FAIL, "unable to allocate memory for attribute ID list")
 
         /* Retrieve the IDs of all opened attributes */
-        H5F_get_obj_ids(loc->file, H5F_OBJ_ATTR | H5F_OBJ_LOCAL, num_open_attr, attr_id_list, FALSE);
+        if(H5F_get_obj_ids(loc->file, H5F_OBJ_ATTR | H5F_OBJ_LOCAL, num_open_attr, attr_id_list, FALSE, &check_num_attr) < 0)
+            HGOTO_ERROR(H5E_ATTR, H5E_CANTGET, FAIL, "can't get IDs of opened attributes")
+	if(check_num_attr != num_open_attr)
+            HGOTO_ERROR(H5E_INTERNAL, H5E_BADITER, FAIL, "open attribute count mismatch")
 
         /* Iterate over the attributes */
         for(u = 0; u < num_open_attr; u++) {
@@ -1260,7 +1264,7 @@ done:
  *
  *-------------------------------------------------------------------------
  */
-static herr_t
+herr_t
 H5O_attr_iterate_real(hid_t loc_id, const H5O_loc_t *loc, hid_t dxpl_id,
     H5_index_t idx_type, H5_iter_order_t order, hsize_t skip,
     hsize_t *last_attr, const H5A_attr_iter_op_t *attr_op, void *op_data)
diff --git a/src/H5Ocopy.c b/src/H5Ocopy.c
index dd649ff..7b812ec 100644
--- a/src/H5Ocopy.c
+++ b/src/H5Ocopy.c
@@ -34,10 +34,12 @@
 /* Headers */
 /***********/
 #include "H5private.h"		/* Generic Functions			*/
+#include "H5Aprivate.h"         /* Attributes                           */
 #include "H5Eprivate.h"		/* Error handling		  	*/
 #include "H5FLprivate.h"	/* Free lists                           */
 #include "H5Iprivate.h"		/* IDs			  		*/
 #include "H5HGprivate.h"        /* Global Heaps                         */
+#include "H5FOprivate.h"        /* File objects                         */
 #include "H5Lprivate.h"         /* Links			  	*/
 #include "H5MFprivate.h"	/* File memory management		*/
 #include "H5MMprivate.h"	/* Memory management			*/
@@ -54,6 +56,20 @@
 /* Local Typedefs */
 /******************/
 
+/* Key object for skiplist of committed datatypes */
+typedef struct H5O_copy_search_comm_dt_key_t {
+    H5T_t               *dt;    /* Datatype */
+    unsigned long       fileno; /* File number */
+} H5O_copy_search_comm_dt_key_t;
+
+/* Callback struct for building a list of committed datatypes */
+typedef struct H5O_copy_search_comm_dt_ud_t {
+    H5SL_t      *dst_dt_list;   /* Skip list of committed datatypes */
+    H5G_loc_t   *dst_root_loc;  /* Starting location for iteration */
+    H5O_loc_t   obj_oloc;       /* Object location (for attribute iteration callback) */
+    hid_t       dxpl_id;        /* Dataset transfer property list id */
+} H5O_copy_search_comm_dt_ud_t;
+
 
 /********************/
 /* Package Typedefs */
@@ -65,14 +81,23 @@
 /********************/
 
 static herr_t H5O_copy_free_addrmap_cb(void *item, void *key, void *op_data);
-static herr_t H5O_copy_header_real(const H5O_loc_t *oloc_src, H5O_loc_t *oloc_dst /*out */,
+static herr_t H5O_copy_header_real(const H5O_loc_t *oloc_src, H5O_loc_t *oloc_dst /*out*/,
     hid_t dxpl_id, H5O_copy_t *cpy_info, H5O_type_t *obj_type, void **udata);
-static herr_t H5O_copy_header(const H5O_loc_t *oloc_src, H5O_loc_t *oloc_dst /*out */,
-    hid_t dxpl_id, unsigned cpy_option);
+static herr_t H5O_copy_header(const H5O_loc_t *oloc_src, H5O_loc_t *oloc_dst /*out*/,
+    hid_t dxpl_id, hid_t ocpypl_id);
 static herr_t H5O_copy_obj(H5G_loc_t *src_loc, H5G_loc_t *dst_loc,
     const char *dst_name, hid_t ocpypl_id, hid_t lcpl_id);
 static herr_t H5O_copy_obj_by_ref(H5O_loc_t *src_oloc, hid_t dxpl_id,
     H5O_loc_t *dst_oloc, H5G_loc_t *dst_root_loc, H5O_copy_t *cpy_info);
+static herr_t H5O_copy_free_comm_dt_cb(void *item, void *key, void *op_data);
+static int H5O_copy_comm_dt_cmp(const void *dt1, const void *dt2);
+static herr_t H5O_copy_search_comm_dt_cb(hid_t group, const char *name,
+    const H5L_info_t *linfo, void *udata);
+static htri_t H5O_copy_search_comm_dt(H5F_t *file_src, H5O_t *oh_src,
+    H5O_loc_t *oloc_dst/*in, out*/, hid_t dxpl_id, H5O_copy_t *cpy_info);
+static herr_t H5O_copy_insert_comm_dt(H5F_t *file_src, H5O_t *oh_src,
+    H5O_loc_t *oloc_dst, hid_t dxpl_id, H5O_copy_t *cpy_info);
+
 
 /*********************/
 /* Package Variables */
@@ -81,6 +106,12 @@ static herr_t H5O_copy_obj_by_ref(H5O_loc_t *src_oloc, hid_t dxpl_id,
 /* Declare a free list to manage the H5O_addr_map_t struct */
 H5FL_DEFINE(H5O_addr_map_t);
 
+/* Declare a free list to manage the H5O_copy_search_comm_dt_key_t struct */
+H5FL_DEFINE(H5O_copy_search_comm_dt_key_t);
+
+/* Declare a free list to manage haddr_t variables */
+H5FL_DEFINE(haddr_t);
+
 
 /*****************************/
 /* Library Private Variables */
@@ -281,11 +312,19 @@ done:
  * Programmer:  Peter Cao
  *              May 30, 2005
  *
+ * Modifications:
+ *	Vailin Choi; Feb 2012
+ *	Bug fix for HDFFV-7853
+ *	When the object is opened, call the object's flush class action
+ *	to ensure that cached data is flushed so that H5Ocopy will get
+ *	the correct data.
+ *	
  *-------------------------------------------------------------------------
  */
 static herr_t
-H5O_copy_header_real(const H5O_loc_t *oloc_src, H5O_loc_t *oloc_dst /*out */,
-    hid_t dxpl_id, H5O_copy_t *cpy_info, H5O_type_t *obj_type, void **udata)
+H5O_copy_header_real(const H5O_loc_t *oloc_src, H5O_loc_t *oloc_dst /*out*/,
+    hid_t dxpl_id, H5O_copy_t *cpy_info, H5O_type_t *obj_type,
+    void **udata /*out*/)
 {
     H5O_addr_map_t         *addr_map = NULL;       /* Address mapping of object copied */
     H5O_t                  *oh_src = NULL;         /* Object header for source object */
@@ -316,19 +355,85 @@ H5O_copy_header_real(const H5O_loc_t *oloc_src, H5O_loc_t *oloc_dst /*out */,
     HDassert(oloc_dst->file);
     HDassert(cpy_info);
 
+    /* Get pointer to object class for this object */
+    if((obj_class = H5O_obj_class(oloc_src, dxpl_id)) == NULL)
+        HGOTO_ERROR(H5E_OHDR, H5E_CANTINIT, FAIL, "unable to determine object type")
+
+    /* Check if the object at the address is already open in the file */
+    if(H5FO_opened(oloc_src->file, oloc_src->addr) != NULL) {
+	
+	H5G_loc_t   tmp_loc; 	/* Location of object */
+	H5O_loc_t   tmp_oloc; 	/* Location of object */
+	H5G_name_t  tmp_path;	/* Object's path */
+
+	tmp_loc.oloc = &tmp_oloc;
+	tmp_loc.path = &tmp_path;
+	tmp_oloc.file = oloc_src->file;
+	tmp_oloc.addr = oloc_src->addr;
+	tmp_oloc.holding_file = oloc_src->holding_file;
+	H5G_name_reset(tmp_loc.path);
+
+	/* Flush the object of this class */
+        if(obj_class->flush && obj_class->flush(&tmp_loc, dxpl_id) < 0)
+            HGOTO_ERROR(H5E_OHDR, H5E_CANTFLUSH, FAIL, "unable to flush object")
+    }
+
     /* Get source object header */
     if(NULL == (oh_src = H5O_protect(oloc_src, dxpl_id, H5AC_READ)))
         HGOTO_ERROR(H5E_OHDR, H5E_CANTPROTECT, FAIL, "unable to load object header")
 
-    /* Get pointer to object class for this object */
-    if(NULL == (obj_class = H5O_obj_class_real(oh_src)))
-        HGOTO_ERROR(H5E_OHDR, H5E_CANTINIT, FAIL, "unable to determine object type")
-
     /* Retrieve user data for particular type of object to copy */
     if(obj_class->get_copy_file_udata &&
             (NULL == (cpy_udata = (obj_class->get_copy_file_udata)())))
         HGOTO_ERROR(H5E_OHDR, H5E_CANTINIT, FAIL, "unable to retrieve copy user data")
 
+    /* If we are merging committed datatypes, check for a match in the destination
+     * file now */
+    if(cpy_info->merge_comm_dt && obj_class->type == H5O_TYPE_NAMED_DATATYPE) {
+        unsigned long fileno_src; /* fileno for source file */
+        unsigned long fileno_dst; /* fileno for destination file */
+        htri_t merge; /* Whether we found a match in the destination file */
+
+        /* Check if the source and dest file are the same.  If so, just return
+         * the source object address */
+        H5F_GET_FILENO(oloc_src->file, fileno_src);
+        H5F_GET_FILENO(oloc_dst->file, fileno_dst);
+        if(fileno_src == fileno_dst) {
+            merge = TRUE;
+            oloc_dst->addr = oloc_src->addr;
+        } /* end if */
+        else
+            /* Search for a matching committed datatype, building the list if
+             * necessary */
+            if((merge = H5O_copy_search_comm_dt(oloc_src->file, oh_src, oloc_dst, dxpl_id, cpy_info)) < 0)
+                HGOTO_ERROR(H5E_OHDR, H5E_CANTGET, FAIL, "can't search for matching committed datatype")
+
+        if(merge) {
+            /* Found a match, add to skip list and exit */
+            /* Allocate space for the address mapping of the object copied */
+            if(NULL == (addr_map = H5FL_MALLOC(H5O_addr_map_t)))
+                HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, FAIL, "memory allocation failed")
+
+            /* Insert the address mapping for the found object into the copied
+             * list */
+            addr_map->src_obj_pos.fileno = fileno_src;
+            addr_map->src_obj_pos.addr = oloc_src->addr;
+            addr_map->dst_addr = oloc_dst->addr;
+            addr_map->is_locked = TRUE;                 /* We've locked the object currently */
+            addr_map->inc_ref_count = 0;                /* Start with no additional ref counts to add */
+            addr_map->obj_class = obj_class;
+            addr_map->udata = cpy_udata;
+
+            /* Insert into skip list */
+            if(H5SL_insert(cpy_info->map_list, addr_map, &(addr_map->src_obj_pos)) < 0) {
+                addr_map = H5FL_FREE(H5O_addr_map_t, addr_map);
+                HGOTO_ERROR(H5E_OHDR, H5E_CANTINSERT, FAIL, "can't insert object into skip list")
+            } /* end if */
+
+            HGOTO_DONE(SUCCEED)
+        } /* end if */
+    } /* end if */
+
     /* Flush any dirty messages in source object header to update the header chunks */
     if(H5O_flush_msgs(oloc_src->file, oh_src) < 0)
         HGOTO_ERROR(H5E_OHDR, H5E_CANTFLUSH, FAIL, "unable to flush object header messages")
@@ -470,38 +575,33 @@ H5O_copy_header_real(const H5O_loc_t *oloc_src, H5O_loc_t *oloc_dst /*out */,
 
         /* copy this message into destination file */
         if(copy_type->copy_file) {
-            htri_t is_shared;           /* Whether message is shared */
             hbool_t recompute_size;     /* Whether copy_file callback created a shared message */
+            unsigned mesg_flags;        /* Message flags */
 
             /* Decode the message if necessary. */
             H5O_LOAD_NATIVE(oloc_src->file, dxpl_id, 0, oh_src, mesg_src, FAIL)
 
+            /* Get destination message flags, and unset shared and shareable
+             * flags.  mesg_dst->flags will contain the original flags for now.
+             */
+            mesg_flags = (unsigned)mesg_dst->flags & ~H5O_MSG_FLAG_SHARED
+                    & ~H5O_MSG_FLAG_SHAREABLE;
+
             /* Copy the source message */
             recompute_size = FALSE;
-            if((mesg_dst->native = H5O_msg_copy_file(copy_type,
-                    oloc_src->file, mesg_src->native, oloc_dst->file,
-                    &recompute_size, cpy_info, cpy_udata, dxpl_id)) == NULL)
+            if((mesg_dst->native = H5O_msg_copy_file(copy_type, oloc_src->file,
+                    mesg_src->native, oloc_dst->file, &recompute_size,
+                    &mesg_flags, cpy_info, cpy_udata, dxpl_id)) == NULL)
                 HGOTO_ERROR(H5E_OHDR, H5E_CANTCOPY, FAIL, "unable to copy object header message")
 
-            /* Check if new message is shared */
-            if((is_shared = H5O_msg_is_shared(copy_type->id, mesg_dst->native)) < 0)
-                HGOTO_ERROR(H5E_OHDR, H5E_CANTGET, FAIL, "unable to query message's shared status")
-
-            /* In being copied, the message may have become shared or stopped
-             * being shared, set/unset its sharing flag.
+            /* Check if the sharing state changed, and recompute the size if so
              */
-            if(is_shared && !(mesg_dst->flags & H5O_MSG_FLAG_SHARED)) {
-                mesg_dst->flags |= H5O_MSG_FLAG_SHARED;
-
-                /* Recompute message size (mesg_dst->native is really shared) */
-                 recompute_size = TRUE;
-            } /* end if */
-            else if(!is_shared && (mesg_dst->flags & H5O_MSG_FLAG_SHARED)) {
-                mesg_dst->flags &= ~H5O_MSG_FLAG_SHARED;
-
-                /* Recompute message size (msg_dest->native is no longer shared) */
+            if(!(mesg_flags & H5O_MSG_FLAG_SHARED)
+                    != !(mesg_dst->flags & H5O_MSG_FLAG_SHARED))
                 recompute_size = TRUE;
-            } /* end if */
+
+            /* Set destination message flags */
+            mesg_dst->flags = (uint8_t)mesg_flags;
 
             /* Recompute message's size */
             /* (its sharing status or one of its components (for attributes)
@@ -671,6 +771,13 @@ H5O_copy_header_real(const H5O_loc_t *oloc_src, H5O_loc_t *oloc_dst /*out */,
     oloc_dst->addr = addr_new;
 
 
+    /* If we are merging committed datatypes and this is a committed datatype, insert
+     * the copied datatype into the list of committed datatypes in the target file.
+     */
+    if(cpy_info->merge_comm_dt && obj_class->type == H5O_TYPE_NAMED_DATATYPE)
+        if(H5O_copy_insert_comm_dt(oloc_src->file, oh_src, oloc_dst, dxpl_id, cpy_info) < 0)
+            HGOTO_ERROR(H5E_OHDR, H5E_CANTGET, FAIL, "can't insert committed datatype into destination list")
+
     /* Allocate space for the address mapping of the object copied */
     if(NULL == (addr_map = H5FL_MALLOC(H5O_addr_map_t)))
         HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, FAIL, "memory allocation failed")
@@ -686,8 +793,10 @@ H5O_copy_header_real(const H5O_loc_t *oloc_src, H5O_loc_t *oloc_dst /*out */,
     addr_map->udata = cpy_udata;
 
     /* Insert into skip list */
-    if(H5SL_insert(cpy_info->map_list, addr_map, &(addr_map->src_obj_pos)) < 0)
+    if(H5SL_insert(cpy_info->map_list, addr_map, &(addr_map->src_obj_pos)) < 0) {
+        addr_map = H5FL_FREE(H5O_addr_map_t, addr_map);
         HGOTO_ERROR(H5E_OHDR, H5E_CANTINSERT, FAIL, "can't insert object into skip list")
+    } /* end if */
 
     /* "post copy" loop over messages, to fix up any messages which require a complete
      * object header for destination object
@@ -716,17 +825,26 @@ H5O_copy_header_real(const H5O_loc_t *oloc_src, H5O_loc_t *oloc_dst /*out */,
         HDassert(copy_type);
 
         if(copy_type->post_copy_file && mesg_src->native) {
+            unsigned mesg_flags;        /* Message flags */
+
             /* Sanity check destination message */
             HDassert(mesg_dst->type == mesg_src->type);
             HDassert(mesg_dst->native);
 
+            /* Get destination message flags.   mesg_dst->flags will contain the
+             * original flags for now. */
+            mesg_flags = (unsigned)mesg_dst->flags;
+
             /* the object header is needed in the post copy for shared message */
             cpy_info->oh_dst = oh_dst;
 
             /* Perform "post copy" operation on message */
             if((copy_type->post_copy_file)(oloc_src, mesg_src->native, oloc_dst,
-                    mesg_dst->native, dxpl_id, cpy_info) < 0)
+                    mesg_dst->native, &mesg_flags, dxpl_id, cpy_info) < 0)
                 HGOTO_ERROR(H5E_OHDR, H5E_CANTINIT, FAIL, "unable to perform 'post copy' operation on message")
+
+            /* Verify that the flags did not change */
+            HDassert(mesg_flags == (unsigned) mesg_dst->flags);
         } /* end if */
     } /* end for */
 
@@ -797,9 +915,9 @@ done:
  *-------------------------------------------------------------------------
  */
 herr_t
-H5O_copy_header_map(const H5O_loc_t *oloc_src, H5O_loc_t *oloc_dst /*out */,
+H5O_copy_header_map(const H5O_loc_t *oloc_src, H5O_loc_t *oloc_dst /*out*/,
     hid_t dxpl_id, H5O_copy_t *cpy_info, hbool_t inc_depth,
-    H5O_type_t *obj_type, void **udata)
+    H5O_type_t *obj_type, void **udata /*out*/)
 {
     H5O_addr_map_t      *addr_map = NULL;       /* Address mapping of object copied */
     H5_obj_t            src_obj_pos;            /* Position of source object */
@@ -937,9 +1055,13 @@ H5O_copy_free_addrmap_cb(void *_item, void UNUSED *key, void UNUSED *op_data)
  */
 static herr_t
 H5O_copy_header(const H5O_loc_t *oloc_src, H5O_loc_t *oloc_dst /*out */,
-    hid_t dxpl_id, unsigned cpy_option)
+    hid_t dxpl_id, hid_t ocpypl_id)
 {
     H5O_copy_t  cpy_info;               /* Information for copying object */
+    H5P_genplist_t  *ocpy_plist;        /* Object copy property list created */
+    H5O_copy_dtype_merge_list_t *dt_list = NULL; /* List of datatype merge suggestions */
+    H5O_mcdt_cb_info_t   cb_info;      	/* Callback info struct */
+    unsigned    cpy_option = 0;         /* Copy options */
     herr_t      ret_value = SUCCEED;
 
     FUNC_ENTER_NOAPI_NOINIT
@@ -949,6 +1071,22 @@ H5O_copy_header(const H5O_loc_t *oloc_src, H5O_loc_t *oloc_dst /*out */,
     HDassert(H5F_addr_defined(oloc_src->addr));
     HDassert(oloc_dst->file);
 
+    /* Get the copy property list */
+    if(NULL == (ocpy_plist = (H5P_genplist_t *)H5I_object(ocpypl_id)))
+        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not a property list")
+
+    /* Retrieve the copy parameters */
+    if(H5P_get(ocpy_plist, H5O_CPY_OPTION_NAME, &cpy_option) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't get object copy flag")
+
+    /* Retrieve the marge committed datatype list */
+    if(H5P_get(ocpy_plist, H5O_CPY_MERGE_COMM_DT_LIST_NAME, &dt_list) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't get merge committed datatype list")
+
+    /* Get callback info */
+    if(H5P_get(ocpy_plist, H5O_CPY_MCDT_SEARCH_CB_NAME, &cb_info) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't get callback info")
+
     /* Convert copy flags into copy struct */
     HDmemset(&cpy_info, 0, sizeof(H5O_copy_t));
     if((cpy_option & H5O_COPY_SHALLOW_HIERARCHY_FLAG) > 0) {
@@ -968,9 +1106,18 @@ H5O_copy_header(const H5O_loc_t *oloc_src, H5O_loc_t *oloc_dst /*out */,
         cpy_info.copy_without_attr = TRUE;
     if((cpy_option & H5O_COPY_PRESERVE_NULL_FLAG) > 0)
         cpy_info.preserve_null = TRUE;
+    if((cpy_option & H5O_COPY_MERGE_COMMITTED_DTYPE_FLAG) > 0)
+        cpy_info.merge_comm_dt = TRUE;
+
+    /* Add dt_list to copy struct */
+    cpy_info.dst_dt_suggestion_list = dt_list;
+
+    /* Add set callback information */
+    cpy_info.mcdt_cb = cb_info.func;
+    cpy_info.mcdt_ud = cb_info.user_data;
 
     /* Create a skip list to keep track of which objects are copied */
-    if((cpy_info.map_list = H5SL_create(H5SL_TYPE_OBJ, NULL)) == NULL)
+    if(NULL == (cpy_info.map_list = H5SL_create(H5SL_TYPE_OBJ, NULL)))
         HGOTO_ERROR(H5E_SLIST, H5E_CANTCREATE, FAIL, "cannot make skip list")
 
     /* copy the object from the source file to the destination file */
@@ -980,6 +1127,8 @@ H5O_copy_header(const H5O_loc_t *oloc_src, H5O_loc_t *oloc_dst /*out */,
 done:
     if(cpy_info.map_list)
         H5SL_destroy(cpy_info.map_list, H5O_copy_free_addrmap_cb, NULL);
+    if(cpy_info.dst_dt_list)
+        H5SL_destroy(cpy_info.dst_dt_list, H5O_copy_free_comm_dt_cb, NULL);
 
     FUNC_LEAVE_NOAPI(ret_value)
 } /* end H5O_copy_header() */
@@ -1001,14 +1150,12 @@ static herr_t
 H5O_copy_obj(H5G_loc_t *src_loc, H5G_loc_t *dst_loc, const char *dst_name,
     hid_t ocpypl_id, hid_t lcpl_id)
 {
-    H5P_genplist_t  *ocpy_plist=NULL;           /* Object copy property list created */
-    hid_t           dxpl_id=H5AC_dxpl_id;
     H5G_name_t      new_path;                   /* Copied object group hier. path */
     H5O_loc_t       new_oloc;                   /* Copied object object location */
     H5G_loc_t       new_loc;                    /* Group location of object copied */
     H5F_t           *cached_dst_file;           /* Cached destination file */
-    hbool_t         entry_inserted=FALSE;       /* Flag to indicate that the new entry was inserted into a group */
-    unsigned        cpy_option = 0;             /* Copy options */
+    hbool_t         entry_inserted = FALSE;     /* Flag to indicate that the new entry was inserted into a group */
+    hid_t           dxpl_id = H5AC_dxpl_id;     /* DXPL for operation */
     herr_t          ret_value = SUCCEED;        /* Return value */
 
     FUNC_ENTER_NOAPI(FAIL)
@@ -1019,14 +1166,6 @@ H5O_copy_obj(H5G_loc_t *src_loc, H5G_loc_t *dst_loc, const char *dst_name,
     HDassert(dst_loc->oloc->file);
     HDassert(dst_name);
 
-    /* Get the copy property list */
-    if(NULL == (ocpy_plist = (H5P_genplist_t *)H5I_object(ocpypl_id)))
-        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not a property list")
-
-    /* Retrieve the copy parameters */
-    if(H5P_get(ocpy_plist, H5O_CPY_OPTION_NAME, &cpy_option) < 0)
-        HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't get object copy flag")
-
     /* Set up copied object location to fill in */
     new_loc.oloc = &new_oloc;
     new_loc.path = &new_path;
@@ -1039,7 +1178,7 @@ H5O_copy_obj(H5G_loc_t *src_loc, H5G_loc_t *dst_loc, const char *dst_name,
     cached_dst_file = dst_loc->oloc->file;
 
     /* Copy the object from the source file to the destination file */
-    if(H5O_copy_header(src_loc->oloc, &new_oloc, dxpl_id, cpy_option) < 0)
+    if(H5O_copy_header(src_loc->oloc, &new_oloc, dxpl_id, ocpypl_id) < 0)
         HGOTO_ERROR(H5E_OHDR, H5E_CANTCOPY, FAIL, "unable to copy object")
 
     /* Patch dst_loc.  Again, this can be removed once oloc's point to shared
@@ -1255,3 +1394,579 @@ done:
     FUNC_LEAVE_NOAPI(ret_value)
 } /* end H5O_copy_expand_ref() */
 
+
+/*-------------------------------------------------------------------------
+ * Function:    H5O_copy_free_comm_dt_cb
+ *
+ * Purpose:     Frees the merge committed dt skip list key and object.
+ *
+ * Return:      SUCCEED (never fails)
+ *
+ * Programmer:  Neil Fortner
+ *              Oct 6 2011
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+H5O_copy_free_comm_dt_cb(void *item, void *_key, void UNUSED *op_data)
+{
+    haddr_t     *addr = (haddr_t *)item;
+    H5O_copy_search_comm_dt_key_t *key = (H5O_copy_search_comm_dt_key_t *)_key;
+
+    FUNC_ENTER_NOAPI_NOINIT
+
+    HDassert(addr);
+    HDassert(key);
+    HDassert(key->dt);
+
+    key->dt = (H5T_t *)H5O_msg_free(H5O_DTYPE_ID, key->dt);
+    key = H5FL_FREE(H5O_copy_search_comm_dt_key_t, key);
+    addr = H5FL_FREE(haddr_t, addr);
+
+    FUNC_LEAVE_NOAPI(SUCCEED)
+} /* end H5O_copy_free_comm_dt_cb */
+
+
+/*-------------------------------------------------------------------------
+ * Function:    H5O_copy_comm_dt_cmp
+ *
+ * Purpose:     Skiplist callback used to compare 2 keys for the merge
+ *              committed dt list.  Mostly a wrapper for H5T_cmp.
+ *
+ * Return:      0 if key1 and key2 are equal.
+ *              <0 if key1 is less than key2.
+ *              >0 if key1 is greater than key2.
+ *
+ * Programmer:  Neil Fortner
+ *              Oct 6 2011
+ *
+ *-------------------------------------------------------------------------
+ */
+static int
+H5O_copy_comm_dt_cmp(const void *_key1, const void *_key2)
+{
+    const H5O_copy_search_comm_dt_key_t *key1 = (const H5O_copy_search_comm_dt_key_t *)_key1;
+    const H5O_copy_search_comm_dt_key_t *key2 = (const H5O_copy_search_comm_dt_key_t *)_key2;
+    int ret_value = 0;
+
+    FUNC_ENTER_NOAPI_NOINIT
+
+    /* Check fileno.  It is unlikely to be different so check if they are equal
+     * first so only one comparison needs to be made. */
+    if(key1->fileno != key2->fileno) {
+        if(key1->fileno < key2->fileno)
+            HGOTO_DONE(-1)
+        if(key1->fileno > key2->fileno)
+            HGOTO_DONE(1)
+    } /* end if */
+
+    ret_value = H5T_cmp(key1->dt, key2->dt, FALSE);
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5O_copy_comm_dt_cmp */
+
+
+/*-------------------------------------------------------------------------
+ * Function:    H5O_copy_search_comm_dt_attr_cb
+ *
+ * Purpose:     Callback for H5O_attr_iterate_real from
+ *              H5O_copy_search_comm_dt_check.  Checks if the attribute's
+ *              datatype is committed.  If it is, adds it to the merge
+ *              committed dt skiplist present in udata if it does not match
+ *              any already present.
+ *
+ * Return:      Non-negative on success/Negative on failure
+ *
+ * Programmer:  Neil Fortner
+ *              Nov 3 2011
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+H5O_copy_search_comm_dt_attr_cb(const H5A_t *attr, void *_udata)
+{
+    H5O_copy_search_comm_dt_ud_t *udata = (H5O_copy_search_comm_dt_ud_t *)_udata;
+    H5T_t       *dt = NULL;             /* Datatype */
+    H5O_copy_search_comm_dt_key_t *key = NULL; /* Skiplist key */
+    haddr_t     *addr = NULL;           /* Destination address */
+    hbool_t     obj_inserted = FALSE;   /* Object inserted into skip list */
+    herr_t      ret_value = SUCCEED;    /* Return value */
+
+    FUNC_ENTER_NOAPI_NOINIT
+
+    /* Sanity checks */
+    HDassert(attr);
+    HDassert(udata);
+    HDassert(udata->dst_dt_list);
+    HDassert(H5F_addr_defined(udata->obj_oloc.addr));
+
+    /* Get attribute datatype */
+    if(NULL == (dt = H5A_type(attr)))
+        HGOTO_ERROR(H5E_OHDR, H5E_CANTGET, FAIL, "can't get attribute datatype")
+
+    /* Check if the datatype is committed and search the skip list if so */
+    if(H5T_committed(dt)) {
+        /* Allocate key */
+        if(NULL == (key = H5FL_MALLOC(H5O_copy_search_comm_dt_key_t)))
+            HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, FAIL, "memory allocation failed")
+
+        /* Copy datatype into key */
+        if(NULL == (key->dt = (H5T_t *)H5O_msg_copy(H5O_DTYPE_ID, dt, NULL)))
+            HGOTO_ERROR(H5E_OHDR, H5E_CANTINIT, FAIL, "unable to copy datatype message")
+
+        /* Get datatype object fileno */
+        H5F_GET_FILENO(udata->obj_oloc.file, key->fileno);
+
+        if(!H5SL_search(udata->dst_dt_list, key)) {
+            /* Allocate destination address */
+            if(NULL == (addr = H5FL_MALLOC(haddr_t)))
+                HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, FAIL, "memory allocation failed")
+
+            /* Add the destination datatype to the skip list */
+            *addr = ((H5O_shared_t *)(key->dt))->u.loc.oh_addr;
+            if(H5SL_insert(udata->dst_dt_list, addr, key) < 0)
+                HGOTO_ERROR(H5E_OHDR, H5E_CANTINSERT, FAIL, "can't insert object into skip list")
+            obj_inserted = TRUE;
+        } /* end if */
+    } /* end if */
+
+done:
+    /* Release resources */
+    if(!obj_inserted) {
+        if(key) {
+            if(key->dt)
+                key->dt = (H5T_t *)H5O_msg_free(H5O_DTYPE_ID, key->dt);
+            key = H5FL_FREE(H5O_copy_search_comm_dt_key_t, key);
+        } /* end if */
+        if(addr) {
+            HDassert(ret_value < 0);
+            addr = H5FL_FREE(haddr_t, addr);
+        } /* end if */
+    } /* end if */
+
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5O_copy_search_comm_dt_attr_cb */
+
+
+/*-------------------------------------------------------------------------
+ * Function:    H5O_copy_search_comm_dt_check
+ *
+ * Purpose:     Check if the object at obj_oloc is or contains a reference
+ *              to a committed datatype.  If it does, adds it to the merge
+ *              committed dt skiplist present in udata if it does not match
+ *              any already present.
+ *
+ * Return:      Non-negative on success/Negative on failure
+ *
+ * Programmer:  Neil Fortner
+ *              Nov 3 2011
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+H5O_copy_search_comm_dt_check(H5O_loc_t *obj_oloc,
+    H5O_copy_search_comm_dt_ud_t *udata)
+{
+    H5O_copy_search_comm_dt_key_t *key = NULL; /* Skiplist key */
+    haddr_t     *addr = NULL;           /* Destination address */
+    hbool_t     obj_inserted = FALSE;   /* Object inserted into skip list */
+    H5O_info_t  oinfo;                  /* Object info */
+    H5A_attr_iter_op_t attr_op;         /* Attribute iteration operator */
+    herr_t      ret_value = SUCCEED;    /* Return value */
+
+    FUNC_ENTER_NOAPI_NOINIT
+
+    /* Sanity checks */
+    HDassert(obj_oloc);
+    HDassert(udata);
+    HDassert(udata->dst_dt_list);
+    HDassert(udata->dst_root_loc);
+
+    /* Get the object's info */
+    if(H5O_get_info(obj_oloc, udata->dxpl_id, TRUE, &oinfo) < 0)
+        HGOTO_ERROR(H5E_OHDR, H5E_CANTGET, FAIL, "unable to get object info")
+
+    /* Check if the object is a datatype, a dataset using a committed
+     * datatype, or contains an attribute using a committed datatype */
+    if(oinfo.type == H5O_TYPE_NAMED_DATATYPE) {
+        /* Allocate key */
+        if(NULL == (key = H5FL_MALLOC(H5O_copy_search_comm_dt_key_t)))
+            HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, FAIL, "memory allocation failed")
+
+        /* Read the destination datatype */
+        if(NULL == (key->dt = (H5T_t *)H5O_msg_read(obj_oloc, H5O_DTYPE_ID, NULL, udata->dxpl_id)))
+            HGOTO_ERROR(H5E_OHDR, H5E_CANTGET, FAIL, "can't read DTYPE message")
+
+        /* Get destination object fileno */
+        H5F_GET_FILENO(obj_oloc->file, key->fileno);
+
+        /* Check if the datatype is already present in the skip list */
+        if(!H5SL_search(udata->dst_dt_list, key)) {
+            /* Allocate destination address */
+            if(NULL == (addr = H5FL_MALLOC(haddr_t)))
+                HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, FAIL, "memory allocation failed")
+
+            /* Add the destination datatype to the skip list */
+            *addr = obj_oloc->addr;
+            if(H5SL_insert(udata->dst_dt_list, addr, key) < 0)
+                HGOTO_ERROR(H5E_OHDR, H5E_CANTINSERT, FAIL, "can't insert object into skip list")
+            obj_inserted = TRUE;
+        } /* end if */
+    } /* end if */
+    else if(oinfo.type == H5O_TYPE_DATASET) {
+        /* Allocate key */
+        if(NULL == (key = H5FL_MALLOC(H5O_copy_search_comm_dt_key_t)))
+            HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, FAIL, "memory allocation failed")
+
+        /* Read the destination datatype */
+        if(NULL == (key->dt = (H5T_t *)H5O_msg_read(obj_oloc, H5O_DTYPE_ID, NULL, udata->dxpl_id)))
+            HGOTO_ERROR(H5E_OHDR, H5E_CANTGET, FAIL, "can't read DTYPE message")
+
+        /* Check if the datatype is committed and search the skip list if so
+            */
+        if(H5T_committed(key->dt)) {
+            /* Get datatype object fileno */
+            H5F_GET_FILENO(obj_oloc->file, key->fileno);
+
+            if(!H5SL_search(udata->dst_dt_list, key)) {
+                /* Allocate destination address */
+                if(NULL == (addr = H5FL_MALLOC(haddr_t)))
+                    HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, FAIL, "memory allocation failed")
+
+                /* Add the destination datatype to the skip list */
+                *addr = ((H5O_shared_t *)(key->dt))->u.loc.oh_addr;
+                if(H5SL_insert(udata->dst_dt_list, addr, key) < 0)
+                    HGOTO_ERROR(H5E_OHDR, H5E_CANTINSERT, FAIL, "can't insert object into skip list")
+                obj_inserted = TRUE;
+            } /* end if */
+        } /* end if */
+    } /* end else */
+
+    /* Search within attributes */
+    attr_op.op_type = H5A_ATTR_OP_LIB;
+    attr_op.u.lib_op = H5O_copy_search_comm_dt_attr_cb;
+    udata->obj_oloc.file = obj_oloc->file;
+    udata->obj_oloc.addr = obj_oloc->addr;
+    if(H5O_attr_iterate_real((hid_t)-1, obj_oloc, udata->dxpl_id, H5_INDEX_NAME, H5_ITER_NATIVE, 0, NULL, &attr_op, udata) < 0)
+        HGOTO_ERROR(H5E_OHDR, H5E_BADITER, FAIL, "error iterating over attributes");
+
+done:
+    /* Release resources */
+    if(!obj_inserted) {
+        if(key) {
+            if(key->dt)
+                key->dt = (H5T_t *)H5O_msg_free(H5O_DTYPE_ID, key->dt);
+            key = H5FL_FREE(H5O_copy_search_comm_dt_key_t, key);
+        } /* end if */
+        if(addr) {
+            HDassert(ret_value < 0);
+            addr = H5FL_FREE(haddr_t, addr);
+        } /* end if */
+    } /* end if */
+
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5O_copy_search_comm_dt_check */
+
+
+/*-------------------------------------------------------------------------
+ * Function:    H5O_copy_search_comm_dt_cb
+ *
+ * Purpose:     H5G_visit callback to add committed datatypes to the merge
+ *              committed dt skiplist.  Mostly a wrapper for
+ *              H5O_copy_search_comm_dt_check.
+ *
+ * Return:      Non-negative on success/Negative on failure
+ *
+ * Programmer:  Neil Fortner
+ *              Oct 6 2011
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+H5O_copy_search_comm_dt_cb(hid_t UNUSED group, const char *name,
+    const H5L_info_t *linfo, void *_udata)
+{
+    H5O_copy_search_comm_dt_ud_t *udata = (H5O_copy_search_comm_dt_ud_t *)_udata; /* Skip list of dtypes in dest file */
+    H5G_loc_t   obj_loc;                /* Location of object */
+    H5O_loc_t   obj_oloc;               /* Object's object location */
+    H5G_name_t  obj_path;               /* Object's group hier. path */
+    hbool_t     obj_found = FALSE;      /* Object at 'name' found */
+    herr_t      ret_value = H5_ITER_CONT; /* Return value */
+
+    FUNC_ENTER_NOAPI_NOINIT
+
+    /* Sanity checks */
+    HDassert(name);
+    HDassert(linfo);
+    HDassert(udata);
+    HDassert(udata->dst_dt_list);
+    HDassert(udata->dst_root_loc);
+
+    /* Check if this is a hard link */
+    if(linfo->type == H5L_TYPE_HARD) {
+        /* Set up opened group location to fill in */
+        obj_loc.oloc = &obj_oloc;
+        obj_loc.path = &obj_path;
+        H5G_loc_reset(&obj_loc);
+
+        /* Find the object */
+        if(H5G_loc_find(udata->dst_root_loc, name, &obj_loc/*out*/, H5P_LINK_ACCESS_DEFAULT, udata->dxpl_id) < 0)
+            HGOTO_ERROR(H5E_OHDR, H5E_NOTFOUND, H5_ITER_ERROR, "object not found")
+        obj_found = TRUE;
+
+        /* Check object and add to skip list if appropriate */
+        if(H5O_copy_search_comm_dt_check(&obj_oloc, udata) < 0)
+            HGOTO_ERROR(H5E_OHDR, H5E_CANTGET, H5_ITER_ERROR, "can't check object")
+    } /* end if */
+
+done:
+    /* Release resources */
+    if(obj_found && H5G_loc_free(&obj_loc) < 0)
+        HDONE_ERROR(H5E_OHDR, H5E_CANTRELEASE, H5_ITER_ERROR, "can't free location")
+
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5O_copy_search_comm_dt_cb */
+
+
+/*-------------------------------------------------------------------------
+ * Function:    H5O_copy_search_comm_dt
+ *
+ * Purpose:     Checks if the committed datatype present in oh_src matches any
+ *              in the destination file, building the destination file
+ *              skiplist as necessary.
+ *
+ * Return:      TRUE if a match is found in the destination file
+ *                      - oloc_dst will contain the address
+ *              FALSE if a match is not found
+ *              Negative on failure
+ *
+ * Programmer:  Neil Fortner
+ *              Sep 27 2011
+ *
+ *-------------------------------------------------------------------------
+ */
+static htri_t
+H5O_copy_search_comm_dt(H5F_t *file_src, H5O_t *oh_src,
+    H5O_loc_t *oloc_dst/*in, out*/, hid_t dxpl_id, H5O_copy_t *cpy_info)
+{
+    H5O_copy_search_comm_dt_key_t *key = NULL; /* Skiplist key */
+    haddr_t     *dst_addr;      /* Destination datatype address */
+    H5G_loc_t   dst_root_loc = {NULL, NULL}; /* Destination root group location */
+    H5O_copy_search_comm_dt_ud_t udata; /* Group iteration user data */
+    herr_t      ret_value = FALSE; /* Return value */
+
+    FUNC_ENTER_NOAPI_NOINIT
+
+    /* Sanity checks */
+    HDassert(oh_src);
+    HDassert(oloc_dst);
+    HDassert(oloc_dst->file);
+    HDassert(H5F_FILE_ID(oloc_dst->file) >= 0);
+    HDassert(cpy_info);
+
+    /* Allocate key */
+    if(NULL == (key = H5FL_MALLOC(H5O_copy_search_comm_dt_key_t)))
+        HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, FAIL, "memory allocation failed")
+
+    /* Read the source datatype */
+    if(NULL == (key->dt = (H5T_t *)H5O_msg_read_oh(file_src, dxpl_id, oh_src, H5O_DTYPE_ID, NULL)))
+        HGOTO_ERROR(H5E_OHDR, H5E_CANTGET, FAIL, "can't read DTYPE message")
+
+    /* Get destination object fileno */
+    H5F_GET_FILENO(oloc_dst->file, key->fileno);
+
+    /* Check if the destination dtype list exists, create it if it does not */
+    if(!cpy_info->dst_dt_list) {
+        /* Create the skip list */
+        if(NULL == (cpy_info->dst_dt_list = H5SL_create(H5SL_TYPE_GENERIC, H5O_copy_comm_dt_cmp)))
+            HGOTO_ERROR(H5E_OHDR, H5E_CANTCREATE, FAIL, "can't create skip list for committed datatypes")
+
+        /* Add suggested types to list, if they are present */
+        if(cpy_info->dst_dt_suggestion_list) {
+            H5O_copy_dtype_merge_list_t *suggestion = cpy_info->dst_dt_suggestion_list;
+            H5G_loc_t   obj_loc;                /* Location of object */
+            H5O_loc_t   obj_oloc;               /* Object's object location */
+            H5G_name_t  obj_path;               /* Object's group hier. path */
+
+            /* Set up the root group in the destination file */
+            if(NULL == (dst_root_loc.oloc = H5G_oloc(H5G_rootof(oloc_dst->file))))
+                HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "unable to get object location for root group")
+            if(NULL == (dst_root_loc.path = H5G_nameof(H5G_rootof(oloc_dst->file))))
+                HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "unable to get path for root group")
+
+            /* Set up opened group location to fill in */
+            obj_loc.oloc = &obj_oloc;
+            obj_loc.path = &obj_path;
+            H5G_loc_reset(&obj_loc);
+
+            /* Build udata */
+            udata.dst_dt_list = cpy_info->dst_dt_list;
+            udata.dst_root_loc = &dst_root_loc;
+            udata.obj_oloc.file = NULL;
+            udata.obj_oloc.addr = HADDR_UNDEF;
+            udata.dxpl_id = dxpl_id;
+
+            /* Walk through the list of datatype suggestions */
+            while(suggestion) {
+                /* Find the object */
+                if(H5G_loc_find(&dst_root_loc, suggestion->path, &obj_loc/*out*/, H5P_LINK_ACCESS_DEFAULT, dxpl_id) < 0)
+                    /* Ignore errors - i.e. suggestions not present in
+                     * destination file */
+                    H5E_clear_stack(NULL);
+                else
+                    /* Check object and add to skip list if appropriate */
+                    if(H5O_copy_search_comm_dt_check(&obj_oloc, &udata) < 0) {
+                        if(H5G_loc_free(&obj_loc) < 0)
+                            HERROR(H5E_OHDR, H5E_CANTRELEASE, "can't free location");
+                        HGOTO_ERROR(H5E_OHDR, H5E_CANTGET, FAIL, "can't check object")
+                    } /* end if */
+
+                /* Free location */
+                if(H5G_loc_free(&obj_loc) < 0)
+                    HGOTO_ERROR(H5E_OHDR, H5E_CANTRELEASE, FAIL, "can't free location");
+
+                /* Advance the suggestion pointer */
+                suggestion = suggestion->next;
+            } /* end while */
+        } /* end if */
+    }
+
+    if(!cpy_info->dst_dt_list_complete) {
+        /* Search for the type in the destination file, and return its address
+         * if found, but only if the list is populated with and only with
+         * suggested types.  We will search complete lists later. */
+        if(cpy_info->dst_dt_suggestion_list
+                && NULL != (dst_addr = (haddr_t *)H5SL_search(
+                cpy_info->dst_dt_list, key))) {
+            oloc_dst->addr = *dst_addr;
+            ret_value = TRUE;
+        } /* end if */
+        else {
+            H5O_mcdt_search_ret_t search_cb_ret = H5O_MCDT_SEARCH_CONT;
+
+            /* Make callback to see if we should search destination file */
+            if(cpy_info->mcdt_cb)
+                if((search_cb_ret = cpy_info->mcdt_cb(cpy_info->mcdt_ud)) == H5O_MCDT_SEARCH_ERROR)
+                    HGOTO_ERROR(H5E_OHDR, H5E_CALLBACK, FAIL, "callback returned error")
+
+            if(search_cb_ret == H5O_MCDT_SEARCH_CONT) {
+                /* Build the complete dst dt list */
+                /* Set up the root group in the destination file, if necessary */
+                if(!dst_root_loc.oloc) {
+                    HDassert(!dst_root_loc.path);
+                    if(NULL == (dst_root_loc.oloc = H5G_oloc(H5G_rootof(oloc_dst->file))))
+                        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "unable to get object location for root group")
+                    if(NULL == (dst_root_loc.path = H5G_nameof(H5G_rootof(oloc_dst->file))))
+                        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "unable to get path for root group")
+                } /* end if */
+                else
+                    HDassert(dst_root_loc.path);
+
+                /* Build udata.  Note that this may be done twice in some cases, but
+                * it should be rare and should be cheaper on average than trying to
+                * keep track of whether it was done before. */
+                udata.dst_dt_list = cpy_info->dst_dt_list;
+                udata.dst_root_loc = &dst_root_loc;
+                udata.obj_oloc.file = NULL;
+                udata.obj_oloc.addr = HADDR_UNDEF;
+                udata.dxpl_id = dxpl_id;
+
+                /* Traverse the destination file, adding committed datatypes to the skip
+                * list */
+                if(H5G_visit(H5F_FILE_ID(oloc_dst->file), "/", H5_INDEX_NAME, H5_ITER_NATIVE, H5O_copy_search_comm_dt_cb, &udata, H5P_LINK_ACCESS_DEFAULT, dxpl_id) < 0)
+                    HGOTO_ERROR(H5E_OHDR, H5E_BADITER, FAIL, "object visitation failed")
+                cpy_info->dst_dt_list_complete = TRUE;
+            } /* end if */
+            else
+                if(search_cb_ret != H5O_MCDT_SEARCH_STOP)
+                    HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "unknown return value for callback")
+        } /* end if */
+    } /* end if */
+
+    /* Search for the type in the destination file, and return its address if
+     * found, but only if the list is complete */
+    if(cpy_info->dst_dt_list_complete) {
+        if(NULL != (dst_addr = (haddr_t *)H5SL_search(cpy_info->dst_dt_list, key))) {
+            oloc_dst->addr = *dst_addr;
+            ret_value = TRUE;
+        } /* end if */
+    } /* end if */
+
+done:
+    if(key) {
+        if(key->dt)
+            key->dt = (H5T_t *)H5O_msg_free(H5O_DTYPE_ID, key->dt);
+        key = H5FL_FREE(H5O_copy_search_comm_dt_key_t, key);
+    } /* end if */
+
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5O_copy_search_comm_dt */
+
+
+/*-------------------------------------------------------------------------
+ * Function:    H5O_copy_insert_comm_dt
+ *
+ * Purpose:     Insert the committed datatype at oloc_dst into the merge committed
+ *              dt skiplist.  The datatype must not be present already.
+ *
+ * Return:      Non-negative on success/Negative on failure
+ *
+ * Programmer:  Neil Fortner
+ *              Oct 6 2011
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+H5O_copy_insert_comm_dt(H5F_t *file_src, H5O_t *oh_src, H5O_loc_t *oloc_dst,
+    hid_t dxpl_id, H5O_copy_t *cpy_info)
+{
+    H5O_copy_search_comm_dt_key_t *key = NULL; /* Skiplist key */
+    haddr_t     *addr = NULL;   /* Destination object address */
+    herr_t      ret_value = SUCCEED; /* Return value */
+
+    FUNC_ENTER_NOAPI_NOINIT
+
+    /* Sanity checks */
+    HDassert(oh_src);
+    HDassert(oloc_dst);
+    HDassert(oloc_dst->file);
+    HDassert(oloc_dst->addr != HADDR_UNDEF);
+    HDassert(cpy_info);
+    HDassert(cpy_info->dst_dt_list);
+
+    /* Allocate key */
+    if(NULL == (key = H5FL_MALLOC(H5O_copy_search_comm_dt_key_t)))
+        HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, FAIL, "memory allocation failed")
+
+    /* Read the datatype.  Read from the source file because the destination
+     * object could be changed in the post-copy. */
+    if(NULL == (key->dt = (H5T_t *)H5O_msg_read_oh(file_src, dxpl_id, oh_src, H5O_DTYPE_ID, NULL)))
+        HGOTO_ERROR(H5E_OHDR, H5E_CANTGET, FAIL, "can't read DTYPE message")
+
+    /* Get destination object fileno */
+    H5F_GET_FILENO(oloc_dst->file, key->fileno);
+
+    /* Allocate destination address */
+    if(NULL == (addr = H5FL_MALLOC(haddr_t)))
+        HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, FAIL, "memory allocation failed")
+
+    /* Add the destination datatype to the skip list */
+    *addr = oloc_dst->addr;
+    if(H5SL_insert(cpy_info->dst_dt_list, addr, key) < 0)
+        HGOTO_ERROR(H5E_OHDR, H5E_CANTINSERT, FAIL, "can't insert object into skip list")
+
+done:
+    if(ret_value < 0) {
+        if(key) {
+            if(key->dt)
+                key->dt = (H5T_t *)H5O_msg_free(H5O_DTYPE_ID, key->dt);
+            key = H5FL_FREE(H5O_copy_search_comm_dt_key_t, key);
+        } /* end if */
+        if(addr)
+            addr = H5FL_FREE(haddr_t, addr);
+    } /* end if */
+
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5O_copy_insert_comm_dt */
+
diff --git a/src/H5Odtype.c b/src/H5Odtype.c
index 9ccb51b..1b602c7 100644
--- a/src/H5Odtype.c
+++ b/src/H5Odtype.c
@@ -43,6 +43,9 @@ static herr_t H5O_dtype_pre_copy_file(H5F_t *file_src, const void *mesg_src,
 static void *H5O_dtype_copy_file(H5F_t *file_src, const H5O_msg_class_t *mesg_type,
     void *native_src, H5F_t *file_dst, hbool_t *recompute_size,
     H5O_copy_t *cpy_info, void *udata, hid_t dxpl_id);
+static herr_t H5O_dtype_shared_post_copy_upd(const H5O_loc_t *src_oloc,
+    const void *mesg_src, H5O_loc_t *dst_oloc, void *mesg_dst, hid_t dxpl_id,
+    H5O_copy_t *cpy_info);
 
 static herr_t H5O_dtype_debug(H5F_t *f, hid_t dxpl_id, const void *_mesg,
     FILE * stream, int indent, int fwidth);
@@ -63,6 +66,7 @@ static herr_t H5O_dtype_debug(H5F_t *f, hid_t dxpl_id, const void *_mesg,
 #define H5O_SHARED_COPY_FILE_REAL	H5O_dtype_copy_file
 #define H5O_SHARED_POST_COPY_FILE	H5O_dtype_shared_post_copy_file
 #undef  H5O_SHARED_POST_COPY_FILE_REAL
+#define H5O_SHARED_POST_COPY_FILE_UPD   H5O_dtype_shared_post_copy_upd
 #define H5O_SHARED_DEBUG		H5O_dtype_shared_debug
 #define H5O_SHARED_DEBUG_REAL		H5O_dtype_debug
 #include "H5Oshared.h"			/* Shared Object Header Message Callbacks */
@@ -1575,6 +1579,40 @@ done:
 } /* end H5O_dtype_copy_file() */
 
 
+/*-------------------------------------------------------------------------
+ * Function:    H5O_dtype_shared_post_copy_upd
+ *
+ * Purpose:     Update a message after the shared message operations
+ *              during the post-copy loop
+ *
+ * Return:      Non-negative on success/Negative on failure
+ *
+ * Programmer:  Neil Fortner
+ *              November 8, 2011
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+H5O_dtype_shared_post_copy_upd(const H5O_loc_t UNUSED *src_oloc,
+    const void UNUSED *mesg_src, H5O_loc_t UNUSED *dst_oloc, void *mesg_dst,
+    hid_t UNUSED dxpl_id, H5O_copy_t UNUSED *cpy_info)
+{
+    H5T_t       *dt_dst = (H5T_t *)mesg_dst;    /* Destination datatype */
+
+    FUNC_ENTER_NOAPI_NOINIT
+
+    if(dt_dst->sh_loc.type == H5O_SHARE_TYPE_COMMITTED) {
+        HDassert(H5T_committed(dt_dst));
+        dt_dst->oloc.file = dt_dst->sh_loc.file;
+        dt_dst->oloc.addr = dt_dst->sh_loc.u.loc.oh_addr;
+    } /* end if */
+    else
+        HDassert(!H5T_committed(dt_dst));
+
+    FUNC_LEAVE_NOAPI(SUCCEED)
+} /* end H5O_dtype_shared_post_copy_upd */
+
+
 /*--------------------------------------------------------------------------
  NAME
     H5O_dtype_debug
diff --git a/src/H5Oefl.c b/src/H5Oefl.c
index e4b21f0..3630cf4 100644
--- a/src/H5Oefl.c
+++ b/src/H5Oefl.c
@@ -36,8 +36,8 @@ static void *H5O_efl_copy(const void *_mesg, void *_dest);
 static size_t H5O_efl_size(const H5F_t *f, hbool_t disable_shared, const void *_mesg);
 static herr_t H5O_efl_reset(void *_mesg);
 static void *H5O_efl_copy_file(H5F_t *file_src, void *mesg_src,
-    H5F_t *file_dst, hbool_t *recompute_size, H5O_copy_t *cpy_info,
-    void *udata, hid_t dxpl_id);
+    H5F_t *file_dst, hbool_t *recompute_size, unsigned *mesg_flags,
+    H5O_copy_t *cpy_info, void *udata, hid_t dxpl_id);
 static herr_t H5O_efl_debug(H5F_t *f, hid_t dxpl_id, const void *_mesg, FILE * stream,
 			    int indent, int fwidth);
 
@@ -455,8 +455,8 @@ done:
  */
 static void *
 H5O_efl_copy_file(H5F_t UNUSED *file_src, void *mesg_src, H5F_t *file_dst,
-    hbool_t UNUSED *recompute_size, H5O_copy_t UNUSED *cpy_info,
-    void UNUSED *_udata, hid_t dxpl_id)
+    hbool_t UNUSED *recompute_size, unsigned UNUSED *mesg_flags,
+    H5O_copy_t UNUSED *cpy_info, void UNUSED *_udata, hid_t dxpl_id)
 {
     H5O_efl_t   *efl_src = (H5O_efl_t *) mesg_src;
     H5O_efl_t   *efl_dst = NULL;
diff --git a/src/H5Ofill.c b/src/H5Ofill.c
index 9fa6108..f5569dc 100644
--- a/src/H5Ofill.c
+++ b/src/H5Ofill.c
@@ -63,6 +63,7 @@ static herr_t H5O_fill_debug(H5F_t *f, hid_t dxpl_id, const void *_mesg, FILE *s
 #undef H5O_SHARED_COPY_FILE_REAL
 #define H5O_SHARED_POST_COPY_FILE	H5O_fill_shared_post_copy_file
 #undef H5O_SHARED_POST_COPY_FILE_REAL
+#undef  H5O_SHARED_POST_COPY_FILE_UPD
 #define H5O_SHARED_DEBUG		H5O_fill_shared_debug
 #define H5O_SHARED_DEBUG_REAL		H5O_fill_debug
 #include "H5Oshared.h"			/* Shared Object Header Message Callbacks */
@@ -95,6 +96,7 @@ static herr_t H5O_fill_debug(H5F_t *f, hid_t dxpl_id, const void *_mesg, FILE *s
 #undef H5O_SHARED_POST_COPY_FILE
 #define H5O_SHARED_POST_COPY_FILE	H5O_fill_new_shared_post_copy_file
 #undef H5O_SHARED_POST_COPY_FILE_REAL
+#undef  H5O_SHARED_POST_COPY_FILE_UPD
 #undef H5O_SHARED_DEBUG
 #define H5O_SHARED_DEBUG		H5O_fill_new_shared_debug
 #undef H5O_SHARED_DEBUG_REAL
diff --git a/src/H5Olayout.c b/src/H5Olayout.c
index 1b17bff..e912d8c 100644
--- a/src/H5Olayout.c
+++ b/src/H5Olayout.c
@@ -46,8 +46,8 @@ static herr_t H5O_layout_free(void *_mesg);
 static herr_t H5O_layout_delete(H5F_t *f, hid_t dxpl_id, H5O_t *open_oh,
     void *_mesg);
 static void *H5O_layout_copy_file(H5F_t *file_src, void *mesg_src,
-    H5F_t *file_dst, hbool_t *recompute_size, H5O_copy_t *cpy_info,
-    void *udata, hid_t dxpl_id);
+    H5F_t *file_dst, hbool_t *recompute_size, unsigned *mesg_flags,
+    H5O_copy_t *cpy_info, void *udata, hid_t dxpl_id);
 static herr_t H5O_layout_debug(H5F_t *f, hid_t dxpl_id, const void *_mesg, FILE * stream,
 			       int indent, int fwidth);
 
@@ -587,8 +587,8 @@ done:
  */
 static void *
 H5O_layout_copy_file(H5F_t *file_src, void *mesg_src, H5F_t *file_dst,
-    hbool_t UNUSED *recompute_size, H5O_copy_t *cpy_info, void *_udata,
-    hid_t dxpl_id)
+    hbool_t UNUSED *recompute_size, unsigned UNUSED *mesg_flags,
+    H5O_copy_t *cpy_info, void *_udata, hid_t dxpl_id)
 {
     H5D_copy_file_ud_t *udata = (H5D_copy_file_ud_t *)_udata;   /* Dataset copying user data */
     H5O_layout_t       *layout_src = (H5O_layout_t *) mesg_src;
diff --git a/src/H5Olinfo.c b/src/H5Olinfo.c
index acdd1e1..e96483a 100644
--- a/src/H5Olinfo.c
+++ b/src/H5Olinfo.c
@@ -46,10 +46,11 @@ static herr_t H5O_linfo_free(void *_mesg);
 static herr_t H5O_linfo_delete(H5F_t *f, hid_t dxpl_id, H5O_t *open_oh,
     void *_mesg);
 static void *H5O_linfo_copy_file(H5F_t *file_src, void *native_src,
-    H5F_t *file_dst, hbool_t *recompute_size, H5O_copy_t *cpy_info,
-    void *udata, hid_t dxpl_id);
-static herr_t H5O_linfo_post_copy_file(const H5O_loc_t *parent_src_oloc, const void *mesg_src, H5O_loc_t *dst_oloc,
-    void *mesg_dst, hid_t dxpl_id, H5O_copy_t *cpy_info);
+    H5F_t *file_dst, hbool_t *recompute_size, unsigned *mesg_flags,
+    H5O_copy_t *cpy_info, void *udata, hid_t dxpl_id);
+static herr_t H5O_linfo_post_copy_file(const H5O_loc_t *parent_src_oloc,
+    const void *mesg_src, H5O_loc_t *dst_oloc, void *mesg_dst,
+    unsigned *mesg_flags, hid_t dxpl_id, H5O_copy_t *cpy_info);
 static herr_t H5O_linfo_debug(H5F_t *f, hid_t dxpl_id, const void *_mesg,
 			     FILE * stream, int indent, int fwidth);
 
@@ -379,8 +380,8 @@ done:
  */
 static void *
 H5O_linfo_copy_file(H5F_t UNUSED *file_src, void *native_src, H5F_t *file_dst,
-    hbool_t UNUSED *recompute_size, H5O_copy_t *cpy_info, void *_udata,
-    hid_t dxpl_id)
+    hbool_t UNUSED *recompute_size, unsigned UNUSED *mesg_flags,
+    H5O_copy_t *cpy_info, void *_udata, hid_t dxpl_id)
 {
     H5O_linfo_t          *linfo_src = (H5O_linfo_t *) native_src;
     H5O_linfo_t          *linfo_dst = NULL;
@@ -501,7 +502,8 @@ done:
  */
 static herr_t
 H5O_linfo_post_copy_file(const H5O_loc_t *src_oloc, const void *mesg_src,
-    H5O_loc_t *dst_oloc, void *mesg_dst, hid_t dxpl_id, H5O_copy_t *cpy_info)
+    H5O_loc_t *dst_oloc, void *mesg_dst, unsigned UNUSED *mesg_flags,
+    hid_t dxpl_id, H5O_copy_t *cpy_info)
 {
     const H5O_linfo_t   *linfo_src = (const H5O_linfo_t *)mesg_src;
     H5O_linfo_t         *linfo_dst = (H5O_linfo_t *)mesg_dst;
diff --git a/src/H5Olink.c b/src/H5Olink.c
index a374807..12171b2 100644
--- a/src/H5Olink.c
+++ b/src/H5Olink.c
@@ -49,10 +49,11 @@ static herr_t H5O_link_free(void *_mesg);
 static herr_t H5O_link_pre_copy_file(H5F_t *file_src, const void *mesg_src,
     hbool_t *deleted, const H5O_copy_t *cpy_info, void *udata);
 static void *H5O_link_copy_file(H5F_t *file_src, void *native_src,
-    H5F_t *file_dst, hbool_t *recompute_size, H5O_copy_t *cpy_info, void *udata,
-    hid_t dxpl_id);
-static herr_t H5O_link_post_copy_file(const H5O_loc_t *src_oloc, const void *mesg_src, H5O_loc_t *dst_oloc,
-    void *mesg_dst, hid_t dxpl_id, H5O_copy_t *cpy_info);
+    H5F_t *file_dst, hbool_t *recompute_size, unsigned *mesg_flags,
+    H5O_copy_t *cpy_info, void *udata, hid_t dxpl_id);
+static herr_t H5O_link_post_copy_file(const H5O_loc_t *src_oloc,
+    const void *mesg_src, H5O_loc_t *dst_oloc, void *mesg_dst,
+    unsigned *mesg_flags, hid_t dxpl_id, H5O_copy_t *cpy_info);
 static herr_t H5O_link_debug(H5F_t *f, hid_t dxpl_id, const void *_mesg,
     FILE * stream, int indent, int fwidth);
 
@@ -717,8 +718,8 @@ H5O_link_pre_copy_file(H5F_t UNUSED *file_src, const void UNUSED *native_src,
  */
 static void *
 H5O_link_copy_file(H5F_t UNUSED *file_src, void *native_src, H5F_t UNUSED *file_dst,
-    hbool_t UNUSED *recompute_size, H5O_copy_t UNUSED *cpy_info, void UNUSED *udata,
-    hid_t UNUSED dxpl_id)
+    hbool_t UNUSED *recompute_size, unsigned UNUSED *mesg_flags,
+    H5O_copy_t UNUSED *cpy_info, void UNUSED *udata, hid_t UNUSED dxpl_id)
 {
     H5O_link_t  *link_src = (H5O_link_t *)native_src;
     void        *ret_value;          /* Return value */
@@ -758,7 +759,8 @@ done:
  */
 static herr_t
 H5O_link_post_copy_file(const H5O_loc_t *src_oloc, const void *mesg_src,
-    H5O_loc_t *dst_oloc, void *mesg_dst, hid_t dxpl_id, H5O_copy_t *cpy_info)
+    H5O_loc_t *dst_oloc, void *mesg_dst, unsigned UNUSED *mesg_flags,
+    hid_t dxpl_id, H5O_copy_t *cpy_info)
 {
     const H5O_link_t    *link_src = (const H5O_link_t *)mesg_src;
     H5O_link_t          *link_dst = (H5O_link_t *)mesg_dst;
diff --git a/src/H5Omessage.c b/src/H5Omessage.c
index f12c835..c9a0997 100644
--- a/src/H5Omessage.c
+++ b/src/H5Omessage.c
@@ -1855,7 +1855,7 @@ done:
 void *
 H5O_msg_copy_file(const H5O_msg_class_t *type, H5F_t *file_src,
     void *native_src, H5F_t *file_dst, hbool_t *recompute_size,
-    H5O_copy_t *cpy_info, void *udata, hid_t dxpl_id)
+    unsigned *mesg_flags, H5O_copy_t *cpy_info, void *udata, hid_t dxpl_id)
 {
     void        *ret_value;
 
@@ -1873,7 +1873,7 @@ H5O_msg_copy_file(const H5O_msg_class_t *type, H5F_t *file_src,
     /* The copy_file callback will return an H5O_shared_t only if the message
      * to be copied is a committed datatype.
      */
-    if(NULL == (ret_value = (type->copy_file)(file_src, native_src, file_dst, recompute_size, cpy_info, udata, dxpl_id)))
+    if(NULL == (ret_value = (type->copy_file)(file_src, native_src, file_dst, recompute_size, mesg_flags, cpy_info, udata, dxpl_id)))
         HGOTO_ERROR(H5E_OHDR, H5E_CANTCOPY, NULL, "unable to copy object header message to file")
 
 done:
@@ -1986,7 +1986,7 @@ H5O_copy_mesg(H5F_t *f, hid_t dxpl_id, H5O_t *oh, unsigned idx,
         HGOTO_ERROR(H5E_OHDR, H5E_CANTINIT, FAIL, "unable to copy message to object header")
 
     /* Update the message flags */
-    idx_msg->flags = mesg_flags;
+    idx_msg->flags = (uint8_t)mesg_flags;
 
     /* Mark the message as modified */
     idx_msg->dirty = TRUE;
diff --git a/src/H5Opkg.h b/src/H5Opkg.h
index a5d01bd..d4cc3fb 100644
--- a/src/H5Opkg.h
+++ b/src/H5Opkg.h
@@ -234,8 +234,8 @@ struct H5O_msg_class_t {
     herr_t	(*set_share)(void*, const H5O_shared_t*);   /* Set shared information */
     htri_t	(*can_share)(const void *);	/* Is message allowed to be shared? */
     herr_t	(*pre_copy_file)(H5F_t *, const void *, hbool_t *, const H5O_copy_t *, void *); /*"pre copy" action when copying native value to file */
-    void	*(*copy_file)(H5F_t *, void *, H5F_t *, hbool_t *, H5O_copy_t *, void *, hid_t); /*copy native value to file */
-    herr_t	(*post_copy_file)(const H5O_loc_t *, const void *, H5O_loc_t *, void *, hid_t, H5O_copy_t *); /*"post copy" action when copying native value to file */
+    void	*(*copy_file)(H5F_t *, void *, H5F_t *, hbool_t *, unsigned *, H5O_copy_t *, void *, hid_t); /*copy native value to file */
+    herr_t	(*post_copy_file)(const H5O_loc_t *, const void *, H5O_loc_t *, void *, unsigned *, hid_t, H5O_copy_t *); /*"post copy" action when copying native value to file */
     herr_t      (*get_crt_index)(const void *, H5O_msg_crt_idx_t *);	/* Get message's creation index */
     herr_t      (*set_crt_index)(void *, H5O_msg_crt_idx_t);	/* Set message's creation index */
     herr_t	(*debug)(H5F_t*, hid_t, const void*, FILE*, int, int);
@@ -325,6 +325,7 @@ typedef struct H5O_obj_class_t {
     void	*(*create)(H5F_t *, void *, H5G_loc_t *, hid_t );	/*create an object of this class */
     H5O_loc_t	*(*get_oloc)(hid_t );		/*get the object header location for an object */
     herr_t      (*bh_info)(H5F_t *f, hid_t dxpl_id, H5O_t *oh, H5_ih_info_t *bh_info); /*get the index & heap info for an object */
+    herr_t      (*flush)(H5G_loc_t *loc, hid_t dxpl_id); 		/*flush an opened object of this class */
 } H5O_obj_class_t;
 
 /* Node in skip list to map addresses from one file to another during object header copy */
@@ -527,7 +528,7 @@ H5_DLL herr_t H5O_msg_flush(H5F_t *f, H5O_t *oh, H5O_mesg_t *mesg);
 H5_DLL herr_t H5O_flush_msgs(H5F_t *f, H5O_t *oh);
 H5_DLL hid_t H5O_open_by_loc(const H5G_loc_t *obj_loc, hid_t lapl_id, hid_t dxpl_id, hbool_t app_ref);
 H5_DLL herr_t H5O_delete_mesg(H5F_t *f, hid_t dxpl_id, H5O_t *open_oh, H5O_mesg_t *mesg);
-H5_DLL const H5O_obj_class_t *H5O_obj_class_real(H5O_t *oh);
+H5_DLL const H5O_obj_class_t * H5O_obj_class(const H5O_loc_t *loc, hid_t dxpl_id);
 H5_DLL int H5O_link_oh(H5F_t *f, int adjust, hid_t dxpl_id, H5O_t *oh, hbool_t *deleted);
 H5_DLL herr_t H5O_inc_rc(H5O_t *oh);
 H5_DLL herr_t H5O_dec_rc(H5O_t *oh);
@@ -549,7 +550,7 @@ H5_DLL herr_t H5O_msg_remove_real(H5F_t *f, H5O_t *oh, const H5O_msg_class_t *ty
     int sequence, H5O_operator_t op, void *op_data, hbool_t adj_link, hid_t dxpl_id);
 H5_DLL void *H5O_msg_copy_file(const H5O_msg_class_t *type, H5F_t *file_src,
     void *mesg_src, H5F_t *file_dst, hbool_t *recompute_size,
-    H5O_copy_t *cpy_info, void *udata, hid_t dxpl_id);
+    unsigned *mesg_flags, H5O_copy_t *cpy_info, void *udata, hid_t dxpl_id);
 H5_DLL herr_t H5O_msg_iterate_real(H5F_t *f, H5O_t *oh, const H5O_msg_class_t *type,
     const H5O_mesg_operator_t *op, void *op_data, hid_t dxpl_id);
 
@@ -586,10 +587,12 @@ H5_DLL herr_t H5O_shared_link(H5F_t *f, hid_t dxpl_id, H5O_t *open_oh,
     const H5O_msg_class_t *mesg_type, H5O_shared_t *sh_mesg);
 H5_DLL herr_t H5O_shared_copy_file(H5F_t *file_src, H5F_t *file_dst,
     const H5O_msg_class_t *mesg_type, const void *_native_src, void *_native_dst,
-    hbool_t *recompute_size, H5O_copy_t *cpy_info, void *udata, hid_t dxpl_id);
+    hbool_t *recompute_size, unsigned *mesg_flags, H5O_copy_t *cpy_info,
+    void *udata, hid_t dxpl_id);
 H5_DLL herr_t H5O_shared_post_copy_file (H5F_t *f,
     const H5O_msg_class_t *mesg_type, const H5O_shared_t *shared_src,
-    H5O_shared_t *shared_dst, hid_t dxpl_id, H5O_copy_t *cpy_info);
+    H5O_shared_t *shared_dst, unsigned *mesg_flags, hid_t dxpl_id,
+    H5O_copy_t *cpy_info);
 H5_DLL herr_t H5O_shared_debug(const H5O_shared_t *mesg, FILE *stream,
     int indent, int fwidth);
 
diff --git a/src/H5Opline.c b/src/H5Opline.c
index 89ce865..f626106 100644
--- a/src/H5Opline.c
+++ b/src/H5Opline.c
@@ -61,6 +61,7 @@ static herr_t H5O_pline_debug(H5F_t *f, hid_t dxpl_id, const void *_mesg,
 #undef H5O_SHARED_COPY_FILE_REAL
 #define H5O_SHARED_POST_COPY_FILE	H5O_pline_shared_post_copy_file
 #undef H5O_SHARED_POST_COPY_FILE_REAL
+#undef  H5O_SHARED_POST_COPY_FILE_UPD
 #define H5O_SHARED_DEBUG		H5O_pline_shared_debug
 #define H5O_SHARED_DEBUG_REAL		H5O_pline_debug
 #include "H5Oshared.h"			/* Shared Object Header Message Callbacks */
diff --git a/src/H5Oprivate.h b/src/H5Oprivate.h
index 97bd9a7..8e2dfa4 100644
--- a/src/H5Oprivate.h
+++ b/src/H5Oprivate.h
@@ -99,7 +99,9 @@ typedef struct H5O_t H5O_t;
 #endif /* H5O_ENABLE_BAD_MESG_COUNT */
 
 /* ========= Object Copy properties ============ */
-#define H5O_CPY_OPTION_NAME 		"copy object"           /* Copy options */
+#define H5O_CPY_OPTION_NAME 		 "copy object"           /* Copy options */
+#define H5O_CPY_MERGE_COMM_DT_LIST_NAME "merge committed dtype list"   /* List of datatype paths to search in the dest file for merging */
+#define H5O_CPY_MCDT_SEARCH_CB_NAME 	 "committed dtype list search" /* Callback function when the search for a matching committed datatype is complete */
 
 /* If the module using this macro is allowed access to the private variables, access them directly */
 #ifdef H5O_PACKAGE
@@ -133,6 +135,18 @@ typedef struct H5O_loc_t {
                                  * its file's count of open objects. */
 } H5O_loc_t;
 
+/* Typedef for linked list of datatype merge suggestions */
+typedef struct H5O_copy_dtype_merge_list_t {
+    char *path; /* Path to datatype in destination file */
+    struct H5O_copy_dtype_merge_list_t *next; /* Next object in list */
+} H5O_copy_dtype_merge_list_t;
+
+/* Structure for callback property before searching the global list of committed datatypes at destination */
+typedef struct H5O_mcdt_cb_info_t {
+    H5O_mcdt_search_cb_t 	func;
+    void  			*user_data;
+} H5O_mcdt_cb_info_t;
+
 /* Settings/flags for copying an object */
 typedef struct H5O_copy_t {
     hbool_t copy_shallow;               /* Flag to perform shallow hierarchy copy */
@@ -141,10 +155,16 @@ typedef struct H5O_copy_t {
     hbool_t expand_ref;                 /* Flag to expand object references */
     hbool_t copy_without_attr;          /* Flag to not copy attributes */
     hbool_t preserve_null;              /* Flag to not delete NULL messages */
+    hbool_t merge_comm_dt;             /* Flag to merge committed datatypes in dest file */
+    H5O_copy_dtype_merge_list_t *dst_dt_suggestion_list; /* Suggestions for merging committed datatypes */
     int     curr_depth;                 /* Current depth in hierarchy copied */
     int     max_depth;                  /* Maximum depth in hierarchy to copy */
     H5SL_t  *map_list;                  /* Skip list to hold address mappings */
+    H5SL_t  *dst_dt_list;               /* Skip list to hold committed datatypes in dest file */
+    hbool_t dst_dt_list_complete;       /* Whether the destination datatype list is complete (i.e. not only populated with "suggestions" from H5Padd_merge_committed_dtype_path) */
     H5O_t   *oh_dst;                    /* The destination object header */
+    H5O_mcdt_search_cb_t mcdt_cb;	/* The callback to invoke before searching the global list of committed datatypes at destination */
+    void *mcdt_ud;			/* User data passed to callback */
 } H5O_copy_t;
 
 /* Header message IDs */
diff --git a/src/H5Opublic.h b/src/H5Opublic.h
index 2379d6b..a7d386a 100644
--- a/src/H5Opublic.h
+++ b/src/H5Opublic.h
@@ -43,7 +43,8 @@
 #define H5O_COPY_EXPAND_REFERENCE_FLAG	(0x0008u)   /* Copy objects that are pointed by references */
 #define H5O_COPY_WITHOUT_ATTR_FLAG      (0x0010u)   /* Copy object without copying attributes */
 #define H5O_COPY_PRESERVE_NULL_FLAG     (0x0020u)   /* Copy NULL messages (empty space) */
-#define H5O_COPY_ALL                    (0x003Fu)   /* All object copying flags (for internal checking) */
+#define H5O_COPY_MERGE_COMMITTED_DTYPE_FLAG (0x0040u)   /* Merge committed datatypes in dest file */
+#define H5O_COPY_ALL                    (0x007Fu)   /* All object copying flags (for internal checking) */
 
 /* Flags for shared message indexes.
  * Pass these flags in using the mesg_type_flags parameter in
@@ -131,6 +132,14 @@ typedef uint32_t H5O_msg_crt_idx_t;
 typedef herr_t (*H5O_iterate_t)(hid_t obj, const char *name, const H5O_info_t *info,
     void *op_data);
 
+typedef enum H5O_mcdt_search_ret_t {
+    H5O_MCDT_SEARCH_ERROR = -1,	/* Abort H5Ocopy */
+    H5O_MCDT_SEARCH_CONT,	/* Continue the global search of all committed datatypes in the destination file */
+    H5O_MCDT_SEARCH_STOP	/* Stop the search, but continue copying.  The committed datatype will be copied but not merged. */
+} H5O_mcdt_search_ret_t;
+
+/* Callback to invoke when completing the search for a matching committed datatype from the committed dtype list */
+typedef H5O_mcdt_search_ret_t (*H5O_mcdt_search_cb_t)(void *op_data);
 
 /********************/
 /* Public Variables */
diff --git a/src/H5Osdspace.c b/src/H5Osdspace.c
index 8ae73f7..905c4e9 100644
--- a/src/H5Osdspace.c
+++ b/src/H5Osdspace.c
@@ -55,6 +55,7 @@ static herr_t H5O_sdspace_debug(H5F_t *f, hid_t dxpl_id, const void *_mesg,
 #undef H5O_SHARED_COPY_FILE_REAL
 #define H5O_SHARED_POST_COPY_FILE	H5O_sdspace_shared_post_copy_file
 #undef H5O_SHARED_POST_COPY_FILE_REAL
+#undef  H5O_SHARED_POST_COPY_FILE_UPD
 #define H5O_SHARED_DEBUG		H5O_sdspace_shared_debug
 #define H5O_SHARED_DEBUG_REAL		H5O_sdspace_debug
 #include "H5Oshared.h"			/* Shared Object Header Message Callbacks */
diff --git a/src/H5Oshared.c b/src/H5Oshared.c
index 4cc30e8..c29e2c7 100644
--- a/src/H5Oshared.c
+++ b/src/H5Oshared.c
@@ -589,8 +589,8 @@ done:
 herr_t
 H5O_shared_copy_file(H5F_t *file_src, H5F_t *file_dst,
     const H5O_msg_class_t *mesg_type, const void *_native_src, void *_native_dst,
-    hbool_t UNUSED *recompute_size, H5O_copy_t *cpy_info, void UNUSED *udata,
-    hid_t dxpl_id)
+    hbool_t UNUSED *recompute_size, unsigned *mesg_flags, H5O_copy_t *cpy_info,
+    void UNUSED *udata, hid_t dxpl_id)
 {
     const H5O_shared_t  *shared_src = (const H5O_shared_t *)_native_src; /* Alias to shared info in native source */
     H5O_shared_t        *shared_dst = (H5O_shared_t *)_native_dst; /* Alias to shared info in native destination message */
@@ -621,16 +621,18 @@ H5O_shared_copy_file(H5F_t *file_src, H5F_t *file_dst,
         /* Set copied metadata tag */
         H5_BEGIN_TAG(dxpl_id, H5AC__COPIED_TAG, FAIL);
 
-        if(H5SM_try_share(file_dst, dxpl_id, NULL, H5SM_DEFER, mesg_type->id, _native_dst, NULL) < 0)
+        if(H5SM_try_share(file_dst, dxpl_id, NULL, H5SM_DEFER, mesg_type->id, _native_dst, mesg_flags) < 0)
             HGOTO_ERROR(H5E_OHDR, H5E_WRITEERROR, FAIL, "unable to determine if message should be shared")
 
         /* Reset metadata tag */
         H5_END_TAG(FAIL);
     } /* end if */
-    else
+    else {
         /* Mark the message as committed - as it will be committed in post copy
          */
         H5O_UPDATE_SHARED(shared_dst, H5O_SHARE_TYPE_COMMITTED, file_dst, mesg_type->id, 0, HADDR_UNDEF)
+        *mesg_flags |= H5O_MSG_FLAG_SHARED;
+    } /* end else */
 
 done:
     FUNC_LEAVE_NOAPI(ret_value)
@@ -657,8 +659,8 @@ done:
  */
 herr_t
 H5O_shared_post_copy_file(H5F_t *f, const H5O_msg_class_t *mesg_type,
-    const H5O_shared_t *shared_src, H5O_shared_t *shared_dst, hid_t dxpl_id,
-    H5O_copy_t *cpy_info)
+    const H5O_shared_t *shared_src, H5O_shared_t *shared_dst,
+    unsigned *mesg_flags, hid_t dxpl_id, H5O_copy_t *cpy_info)
 {
     herr_t ret_value = SUCCEED;         /* Return value */
 
@@ -675,6 +677,7 @@ H5O_shared_post_copy_file(H5F_t *f, const H5O_msg_class_t *mesg_type,
         H5O_loc_t src_oloc;
 
         /* Copy the shared object from source to destination */
+        H5O_loc_reset(&dst_oloc);
         dst_oloc.file = f;
         src_oloc.file = shared_src->file;
         src_oloc.addr = shared_src->u.loc.oh_addr;
@@ -688,7 +691,7 @@ H5O_shared_post_copy_file(H5F_t *f, const H5O_msg_class_t *mesg_type,
     else
         /* Share the message */
         if(H5SM_try_share(f, dxpl_id, NULL, H5SM_WAS_DEFERRED, mesg_type->id,
-                shared_dst, NULL) < 0)
+                shared_dst, mesg_flags) < 0)
             HGOTO_ERROR(H5E_OHDR, H5E_BADMESG, FAIL, "can't share message")
 
 done:
diff --git a/src/H5Oshared.h b/src/H5Oshared.h
index ddacc25..3ec5709 100644
--- a/src/H5Oshared.h
+++ b/src/H5Oshared.h
@@ -320,7 +320,8 @@ done:
  */
 static H5_inline void *
 H5O_SHARED_COPY_FILE(H5F_t *file_src, void *_native_src, H5F_t *file_dst,
-    hbool_t *recompute_size, H5O_copy_t *cpy_info, void *udata, hid_t dxpl_id)
+    hbool_t *recompute_size, unsigned *mesg_flags, H5O_copy_t *cpy_info,
+    void *udata, hid_t dxpl_id)
 {
     void *dst_mesg = NULL;      /* Destination message */
     void *ret_value;            /* Return value */
@@ -348,8 +349,8 @@ H5O_SHARED_COPY_FILE(H5F_t *file_src, void *_native_src, H5F_t *file_dst,
     HDmemset(dst_mesg, 0, sizeof(H5O_shared_t));
 
     /* Handle sharing destination message */
-    if(H5O_shared_copy_file(file_src, file_dst, H5O_SHARED_TYPE,
-            _native_src, dst_mesg, recompute_size, cpy_info, udata, dxpl_id) < 0)
+    if(H5O_shared_copy_file(file_src, file_dst, H5O_SHARED_TYPE, _native_src,
+            dst_mesg, recompute_size, mesg_flags, cpy_info, udata, dxpl_id) < 0)
         HGOTO_ERROR(H5E_OHDR, H5E_WRITEERROR, NULL, "unable to determine if message should be shared")
 
     /* Set return value */
@@ -383,7 +384,8 @@ done:
  */
 static H5_inline herr_t
 H5O_SHARED_POST_COPY_FILE(const H5O_loc_t *oloc_src, const void *mesg_src,
-    H5O_loc_t *oloc_dst, void *mesg_dst, hid_t dxpl_id, H5O_copy_t *cpy_info)
+    H5O_loc_t *oloc_dst, void *mesg_dst, unsigned *mesg_flags, hid_t dxpl_id,
+    H5O_copy_t *cpy_info)
 {
     const H5O_shared_t  *shared_src = (const H5O_shared_t *)mesg_src; /* Alias to shared info in native source */
     H5O_shared_t        *shared_dst = (H5O_shared_t *)mesg_dst; /* Alias to shared info in native destination */
@@ -405,7 +407,7 @@ H5O_SHARED_POST_COPY_FILE(const H5O_loc_t *oloc_src, const void *mesg_src,
 #endif /* H5O_SHARED_POST_COPY_FILE */
 
 #ifdef H5O_SHARED_POST_COPY_FILE_REAL
-    /* Call native message's copy file callback to copy the message */
+    /* Call native message's post copy file callback to copy the message */
     if(H5O_SHARED_POST_COPY_FILE_REAL(oloc_src, mesg_src, oloc_dst, mesg_dst, dxpl_id, cpy_info) <0 )
         HGOTO_ERROR(H5E_OHDR, H5E_CANTCOPY, FAIL, "unable to copy native message to another file")
 #endif /* H5O_SHARED_POST_COPY_FILE_REAL */
@@ -414,9 +416,16 @@ H5O_SHARED_POST_COPY_FILE(const H5O_loc_t *oloc_src, const void *mesg_src,
      * production if the DEFER pass determined it will not be shared; debug mode
      * verifies that it is indeed the case */
     if(H5O_shared_post_copy_file(oloc_dst->file, H5O_SHARED_TYPE,
-            shared_src, shared_dst, dxpl_id, cpy_info) < 0)
+            shared_src, shared_dst, mesg_flags, dxpl_id, cpy_info) < 0)
         HGOTO_ERROR(H5E_OHDR, H5E_WRITEERROR, FAIL, "unable to fix shared message in post copy")
 
+#ifdef H5O_SHARED_POST_COPY_FILE_UPD
+    /* Call native message's post copy file update callback to update the
+     * message */
+    if(H5O_SHARED_POST_COPY_FILE_UPD(oloc_src, mesg_src, oloc_dst, mesg_dst, dxpl_id, cpy_info) < 0)
+        HGOTO_ERROR(H5E_OHDR, H5E_CANTCOPY, FAIL, "unable to update native message")
+#endif /* H5O_SHARED_POST_COPY_FILE_UPD */
+
     /* Make sure that if the the source or destination is committed, both are
      * committed */
     HDassert((shared_src->type == H5O_SHARE_TYPE_COMMITTED)
diff --git a/src/H5Ostab.c b/src/H5Ostab.c
index 42cd92c..d5f5f86 100644
--- a/src/H5Ostab.c
+++ b/src/H5Ostab.c
@@ -44,10 +44,11 @@ static size_t H5O_stab_size(const H5F_t *f, hbool_t disable_shared, const void *
 static herr_t H5O_stab_free(void *_mesg);
 static herr_t H5O_stab_delete(H5F_t *f, hid_t dxpl_id, H5O_t *open_oh, void *_mesg);
 static void *H5O_stab_copy_file(H5F_t *file_src, void *native_src,
-    H5F_t *file_dst, hbool_t *recompute_size, H5O_copy_t *cpy_info, void *_udata,
-    hid_t dxpl_id);
-static herr_t H5O_stab_post_copy_file(const H5O_loc_t *src_oloc, const void *mesg_src, H5O_loc_t *dst_oloc,
-    void *mesg_dst, hid_t dxpl_id, H5O_copy_t *cpy_info);
+    H5F_t *file_dst, hbool_t *recompute_size, unsigned *mesg_flags,
+    H5O_copy_t *cpy_info, void *_udata, hid_t dxpl_id);
+static herr_t H5O_stab_post_copy_file(const H5O_loc_t *src_oloc,
+    const void *mesg_src, H5O_loc_t *dst_oloc, void *mesg_dst,
+    unsigned *mesg_flags, hid_t dxpl_id, H5O_copy_t *cpy_info);
 static herr_t H5O_stab_debug(H5F_t *f, hid_t dxpl_id, const void *_mesg,
     FILE * stream, int indent, int fwidth);
 
@@ -307,8 +308,8 @@ done:
  */
 static void *
 H5O_stab_copy_file(H5F_t *file_src, void *native_src, H5F_t *file_dst,
-    hbool_t UNUSED *recompute_size, H5O_copy_t UNUSED *cpy_info, void *_udata,
-    hid_t dxpl_id)
+    hbool_t UNUSED *recompute_size, unsigned UNUSED *mesg_flags,
+    H5O_copy_t UNUSED *cpy_info, void *_udata, hid_t dxpl_id)
 {
     H5O_stab_t          *stab_src = (H5O_stab_t *) native_src;
     H5O_stab_t          *stab_dst = NULL;
@@ -370,8 +371,9 @@ done:
  *-------------------------------------------------------------------------
  */
 static herr_t
-H5O_stab_post_copy_file(const H5O_loc_t *src_oloc, const void *mesg_src, H5O_loc_t *dst_oloc,
-    void *mesg_dst, hid_t dxpl_id, H5O_copy_t *cpy_info)
+H5O_stab_post_copy_file(const H5O_loc_t *src_oloc, const void *mesg_src,
+    H5O_loc_t *dst_oloc, void *mesg_dst, unsigned UNUSED *mesg_flags,
+    hid_t dxpl_id, H5O_copy_t *cpy_info)
 {
     const H5O_stab_t    *stab_src = (const H5O_stab_t *)mesg_src;
     H5O_stab_t          *stab_dst = (H5O_stab_t *)mesg_dst;
diff --git a/src/H5Pdcpl.c b/src/H5Pdcpl.c
index f07aa87..0a41371 100644
--- a/src/H5Pdcpl.c
+++ b/src/H5Pdcpl.c
@@ -410,7 +410,7 @@ H5P_dcrt_layout_cmp(const void *_layout1, const void *_layout2, size_t UNUSED si
 
     /* Sanity check */
     HDassert(layout1);
-    HDassert(layout1);
+    HDassert(layout2);
     HDassert(size == sizeof(H5O_layout_t));
 
     /* Check for different layout type */
diff --git a/src/H5Pfapl.c b/src/H5Pfapl.c
index c75cf61..2d46ec7 100644
--- a/src/H5Pfapl.c
+++ b/src/H5Pfapl.c
@@ -40,6 +40,7 @@
 #include "H5FDprivate.h"	/* File drivers				*/
 #include "H5VLprivate.h"	/* VOL plugins				*/
 #include "H5Iprivate.h"		/* IDs			  		*/
+#include "H5MMprivate.h"        /* Memory Management    */
 #include "H5Ppkg.h"		/* Property lists		  	*/
 
 /* Includes needed to set as default file driver */
@@ -125,10 +126,18 @@
 /* Definition for external file cache size */
 #define H5F_ACS_EFC_SIZE_SIZE                   sizeof(unsigned)
 #define H5F_ACS_EFC_SIZE_DEF                    0
+
 /* Definition for VOL plugin */
 #define H5F_ACS_VOL_SIZE                sizeof(void *)
 #define H5F_ACS_VOL_DEF                 H5VL_NATIVE
 
+/* Definition of pointer to initial file image info */
+#define H5F_ACS_FILE_IMAGE_INFO_SIZE            sizeof(H5FD_file_image_info_t)
+#define H5F_ACS_FILE_IMAGE_INFO_DEF             H5FD_DEFAULT_FILE_IMAGE_INFO
+#define H5F_ACS_FILE_IMAGE_INFO_DEL             H5P_file_image_info_del
+#define H5F_ACS_FILE_IMAGE_INFO_COPY            H5P_file_image_info_copy
+#define H5F_ACS_FILE_IMAGE_INFO_CLOSE           H5P_file_image_info_close
+
 /******************/
 /* Local Typedefs */
 /******************/
@@ -154,6 +163,10 @@ static herr_t H5P_facc_reg_prop(H5P_genclass_t *pclass);
 static herr_t H5P_facc_create(hid_t fapl_id, void *copy_data);
 static herr_t H5P_facc_copy(hid_t new_plist_t, hid_t old_plist_t, void *copy_data);
 
+/* File image info property callbacks */
+static herr_t H5P_file_image_info_del(hid_t prop_id, const char *name, size_t size, void *value);
+static herr_t H5P_file_image_info_copy(const char *name, size_t size, void *value);
+static herr_t H5P_file_image_info_close(const char *name, size_t size, void *value);
 
 /*********************/
 /* Package Variables */
@@ -221,6 +234,7 @@ H5P_facc_reg_prop(H5P_genclass_t *pclass)
     hbool_t want_posix_fd = H5F_ACS_WANT_POSIX_FD_DEF;          /* Default setting for retrieving 'handle' from core VFD */
     unsigned efc_size = H5F_ACS_EFC_SIZE_DEF;                   /* Default external file cache size */
     H5VL_class_t *vol_cls = H5F_ACS_VOL_DEF;                    /* Default VOL plugin */
+    H5FD_file_image_info_t file_image_info = H5F_ACS_FILE_IMAGE_INFO_DEF;  /* Default file image info and callbacks */
     herr_t ret_value = SUCCEED;         /* Return value */
 
     FUNC_ENTER_NOAPI_NOINIT
@@ -310,6 +324,10 @@ H5P_facc_reg_prop(H5P_genclass_t *pclass)
     if(H5P_register_real(pclass, H5F_ACS_VOL_NAME, H5F_ACS_VOL_SIZE, &vol_cls, NULL, NULL, NULL, NULL, NULL, NULL, NULL) < 0)
          HGOTO_ERROR(H5E_PLIST, H5E_CANTINSERT, FAIL, "can't insert property into class")
 
+    /* Register the initial file image info */
+    if(H5P_register_real(pclass, H5F_ACS_FILE_IMAGE_INFO_NAME, H5F_ACS_FILE_IMAGE_INFO_SIZE, &file_image_info, NULL, NULL, NULL, H5F_ACS_FILE_IMAGE_INFO_DEL, H5F_ACS_FILE_IMAGE_INFO_COPY, NULL, H5F_ACS_FILE_IMAGE_INFO_CLOSE) < 0)
+         HGOTO_ERROR(H5E_PLIST, H5E_CANTINSERT, FAIL, "can't insert property into class")
+
 done:
     FUNC_LEAVE_NOAPI(ret_value)
 } /* end H5P_facc_reg_prop() */
@@ -2140,7 +2158,6 @@ done:
     FUNC_LEAVE_API(ret_value)
 } /* end H5Pget_elink_file_cache_size() */
 
-/* MSC Begin update */
 
 /*-------------------------------------------------------------------------
  * Function:	H5P_set_vol
@@ -2184,3 +2201,484 @@ H5P_set_vol(H5P_genplist_t *plist, H5VL_class_t *vol_cls)
 done:
     FUNC_LEAVE_NOAPI(ret_value)
 } /* end H5P_set_vol() */
+
+
+/*-------------------------------------------------------------------------
+ * Function: H5Pset_file_image
+ *
+ * Purpose:     Sets the initial file image. Some file drivers can initialize 
+ *              the starting data in a file from a buffer. 
+ *              
+ * Return:      Non-negative on success/Negative on failure
+ *
+ * Programmer:  Jacob Gruber
+ *              Thurday, August 11, 2011
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5Pset_file_image(hid_t fapl_id, void *buf_ptr, size_t buf_len)
+{
+    H5P_genplist_t *fapl;               /* Property list pointer */
+    H5FD_file_image_info_t image_info;  /* File image info */
+    herr_t ret_value = SUCCEED;         /* Return value */
+    
+    FUNC_ENTER_API(FAIL)
+    H5TRACE3("e", "i*xz", fapl_id, buf_ptr, buf_len);
+
+    /* validate parameters */
+    if(!(((buf_ptr == NULL) && (buf_len == 0)) || ((buf_ptr != NULL) && (buf_len > 0))))
+        HGOTO_ERROR (H5E_ARGS, H5E_BADVALUE, FAIL, "inconsistant buf_ptr and buf_len");
+   
+    /* Get the plist structure */
+    if(NULL == (fapl = H5P_object_verify(fapl_id, H5P_FILE_ACCESS)))
+        HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, FAIL, "can't find object for ID")
+        
+    /* Get old image info */
+    if(H5P_get(fapl, H5F_ACS_FILE_IMAGE_INFO_NAME, &image_info) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't get old file image pointer")
+        
+    /* Release previous buffer, if it exists */
+    if(image_info.buffer != NULL) {
+        if(image_info.callbacks.image_free) {
+            if(SUCCEED != image_info.callbacks.image_free(image_info.buffer, H5FD_FILE_IMAGE_OP_PROPERTY_LIST_SET, image_info.callbacks.udata))
+                HGOTO_ERROR(H5E_RESOURCE, H5E_CANTFREE, FAIL, "image_free callback failed")
+        } /* end if */
+        else
+            H5MM_xfree(image_info.buffer);
+    } /* end if */  
+    
+    /* Update struct */
+    if(buf_ptr) {
+        /* Allocate memory */
+        if(image_info.callbacks.image_malloc) {
+            if(NULL == (image_info.buffer = image_info.callbacks.image_malloc(buf_len,
+                    H5FD_FILE_IMAGE_OP_PROPERTY_LIST_SET, image_info.callbacks.udata)))
+                HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, FAIL, "image malloc callback failed")
+         } /* end if */
+         else
+            if(NULL == (image_info.buffer = H5MM_malloc(buf_len)))
+                HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, FAIL, "unable to allocate memory block")
+    
+        /* Copy data */
+        if(image_info.callbacks.image_memcpy) {
+            if(image_info.buffer != image_info.callbacks.image_memcpy(image_info.buffer, 
+                   buf_ptr, buf_len, H5FD_FILE_IMAGE_OP_PROPERTY_LIST_SET, 
+                   image_info.callbacks.udata))
+	        HGOTO_ERROR(H5E_RESOURCE, H5E_CANTCOPY, FAIL, "image_memcpy callback failed")
+        } /* end if */
+	else
+            HDmemcpy(image_info.buffer, buf_ptr, buf_len);
+    } /* end if */
+    else
+        image_info.buffer = NULL;
+
+    image_info.size = buf_len;
+
+    /* Set values */
+    if(H5P_set(fapl, H5F_ACS_FILE_IMAGE_INFO_NAME, &image_info) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTSET, FAIL, "can't set file image info")
+
+done:
+    FUNC_LEAVE_API(ret_value)
+} /* end H5Pset_file_image() */
+
+
+/*-------------------------------------------------------------------------
+ * Function: H5Pget_file_image
+ *
+ * Purpose:     If the file image exists and buf_ptr_ptr is not NULL, 
+ *		allocate a buffer of the correct size, copy the image into 
+ *		the new buffer, and return the buffer to the caller in 
+ *		*buf_ptr_ptr.  Do this using the file image callbacks
+ *		if defined.  
+ *
+ *		NB: It is the responsibility of the caller to free the 
+ *		buffer whose address is returned in *buf_ptr_ptr.  Do
+ *		this using free if the file image callbacks are not 
+ *		defined, or with whatever method is appropriate if 
+ *		the callbacks are defined.
+ *
+ *              If buf_ptr_ptr is not NULL, and no image exists, set 
+ *		*buf_ptr_ptr to NULL.
+ *
+ *		If buf_len_ptr is not NULL, set *buf_len_ptr equal
+ *		to the length of the file image if it exists, and 
+ *		to 0 if it does not.
+ *
+ * Return:      Non-negative on success/Negative on failure
+ *
+ * Programmer:  Jacob Gruber
+ *              Thurday, August 11, 2011
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5Pget_file_image(hid_t fapl_id, void **buf_ptr_ptr, size_t *buf_len_ptr)
+{
+    H5P_genplist_t *fapl;               /* Property list pointer */
+    H5FD_file_image_info_t image_info;  /* File image info */
+    herr_t ret_value = SUCCEED;         /* Return value */
+
+    FUNC_ENTER_API(FAIL)
+    H5TRACE3("e", "i**x*z", fapl_id, buf_ptr_ptr, buf_len_ptr);
+
+    /* Get the plist structure */
+    if(NULL == (fapl = H5P_object_verify(fapl_id, H5P_FILE_ACCESS)))
+        HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, FAIL, "can't find object for ID")
+
+    /* Get values */
+    if(H5P_get(fapl, H5F_ACS_FILE_IMAGE_INFO_NAME, &image_info) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't get file image info")
+
+    /* verify file image field consistancy */
+    HDassert(((image_info.buffer != NULL) && (image_info.size > 0)) || 
+             ((image_info.buffer == NULL) && (image_info.size == 0)));
+
+    /* Set output size */
+    if(buf_len_ptr != NULL)
+        *buf_len_ptr = image_info.size;
+
+    /* Duplicate the image if desired, using callbacks if available */
+    if(buf_ptr_ptr != NULL) {
+        void * copy_ptr = NULL;         /* Copy of memory image */
+
+        if(image_info.buffer != NULL) {
+            /* Allocate memory */
+            if(image_info.callbacks.image_malloc) {
+                if(NULL == (copy_ptr = image_info.callbacks.image_malloc(image_info.size,
+                        H5FD_FILE_IMAGE_OP_PROPERTY_LIST_GET, image_info.callbacks.udata)))
+                    HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, FAIL, "image malloc callback failed")
+            } /* end if */
+            else
+                if(NULL == (copy_ptr = H5MM_malloc(image_info.size)))
+                    HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, FAIL, "unable to allocate copy")
+    
+            /* Copy data */
+            if(image_info.callbacks.image_memcpy) {
+                if(copy_ptr != image_info.callbacks.image_memcpy(copy_ptr, image_info.buffer,
+                        image_info.size, H5FD_FILE_IMAGE_OP_PROPERTY_LIST_GET, 
+                        image_info.callbacks.udata))
+                    HGOTO_ERROR(H5E_RESOURCE, H5E_CANTCOPY, FAIL, "image_memcpy callback failed")
+            } /* end if */
+	    else
+                HDmemcpy(copy_ptr, image_info.buffer, image_info.size);
+        } /* end if */
+
+        *buf_ptr_ptr = copy_ptr;
+    } /* end if */
+
+done:
+    FUNC_LEAVE_API(ret_value)
+} /* end H5Pget_file_image */
+
+
+/*-------------------------------------------------------------------------
+ * Function: H5Pset_file_image_callbacks
+ *
+ * Purpose:     Sets the callbacks for file images. Some file drivers allow
+ *              the use of user-defined callbacks for allocating, freeing and
+ *              copying the drivers internal buffer, potentially allowing a 
+ *              clever user to do optimizations such as avoiding large mallocs
+ *              and memcpys or to perform detailed logging.
+ *
+ * Return:      Non-negative on success/Negative on failure
+ *
+ * Programmer:  Jacob Gruber
+ *              Thurday, August 11, 2011
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5Pset_file_image_callbacks(hid_t fapl_id, H5FD_file_image_callbacks_t *callbacks_ptr)
+{
+    H5P_genplist_t *fapl;               /* Property list pointer */
+    H5FD_file_image_info_t info;        /* File image info */
+    herr_t ret_value = SUCCEED;         /* Return value */
+
+    FUNC_ENTER_API(FAIL)
+    H5TRACE2("e", "i*x", fapl_id, callbacks_ptr);
+
+    /* Get the plist structure */
+    if(NULL == (fapl = H5P_object_verify(fapl_id, H5P_FILE_ACCESS)))
+        HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, FAIL, "can't find object for ID")
+
+    /* Get old info */
+    if(H5P_get(fapl, H5F_ACS_FILE_IMAGE_INFO_NAME, &info) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't get old file image info")
+
+    /* verify file image field consistancy */
+    HDassert(((info.buffer != NULL) && (info.size > 0)) || 
+             ((info.buffer == NULL) && (info.size == 0)));
+
+    /* Make sure a file image hasn't already been set */
+    if(info.buffer != NULL || info.size > 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_SETDISALLOWED, FAIL, "setting callbacks when an image is already set is forbidden. It could cause memory leaks.")
+
+    /* verify that callbacks_ptr is not NULL */
+    if(NULL == callbacks_ptr)
+	HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "NULL callbacks_ptr")
+
+    /* Make sure udata callbacks are going to be set if udata is going to be set */
+    if(callbacks_ptr->udata)
+        if(callbacks_ptr->udata_copy == NULL || callbacks_ptr->udata_free == NULL)
+            HGOTO_ERROR(H5E_PLIST, H5E_SETDISALLOWED, FAIL, "udata callbacks must be set if udata is set")
+
+    /* Release old udata if it exists */
+    if(info.callbacks.udata != NULL) {
+        HDassert(info.callbacks.udata_free);
+        if(info.callbacks.udata_free(info.callbacks.udata) < 0)
+	    HGOTO_ERROR(H5E_RESOURCE, H5E_CANTFREE, FAIL, "udata_free callback failed")
+    } /* end if */
+
+    /* Update struct */
+    info.callbacks = *callbacks_ptr;
+
+    if(callbacks_ptr->udata) {
+        HDassert(callbacks_ptr->udata_copy);
+        HDassert(callbacks_ptr->udata_free);
+        if((info.callbacks.udata = callbacks_ptr->udata_copy(callbacks_ptr->udata)) == NULL)
+            HGOTO_ERROR(H5E_PLIST, H5E_CANTSET, FAIL, "can't copy the suppplied udata")
+    } /* end if */
+
+    /* Set values */
+    if(H5P_set(fapl, H5F_ACS_FILE_IMAGE_INFO_NAME, &info) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTSET, FAIL, "can't set file image info")
+
+done:
+    FUNC_LEAVE_API(ret_value)
+} /* end H5Pset_file_image_callbacks() */
+
+
+/*-------------------------------------------------------------------------
+ * Function: H5Pget_file_image_callbacks
+ *
+ * Purpose:     Sets the callbacks for file images. Some file drivers allow
+ *              the use of user-defined callbacks for allocating, freeing and
+ *              copying the drivers internal buffer, potentially allowing a 
+ *              clever user to do optimizations such as avoiding large mallocs
+ *
+ * Return:      Non-negative on success/Negative on failure
+ *
+ * Programmer:  Jacob Gruber
+ *              Thurday, August 11, 2011
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5Pget_file_image_callbacks(hid_t fapl_id, H5FD_file_image_callbacks_t *callbacks_ptr)
+{
+    H5P_genplist_t *fapl;               /* Property list pointer */
+    H5FD_file_image_info_t info;        /* File image info */
+    herr_t ret_value = SUCCEED;         /* Return value */
+
+    FUNC_ENTER_API(FAIL)
+    H5TRACE2("e", "i*x", fapl_id, callbacks_ptr);
+
+    /* Get the plist structure */
+    if(NULL == (fapl = H5P_object_verify(fapl_id, H5P_FILE_ACCESS)))
+        HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, FAIL, "can't find object for ID")
+
+    /* Get old info */
+    if(H5P_get(fapl, H5F_ACS_FILE_IMAGE_INFO_NAME, &info) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't get file image info")
+
+    /* verify file image field consistancy */
+    HDassert(((info.buffer != NULL) && (info.size > 0)) || 
+             ((info.buffer == NULL) && (info.size == 0)));
+
+    /* verify that callbacks_ptr is not NULL */
+    if(NULL == callbacks_ptr)
+	HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "NULL callbacks_ptr")
+
+    /* Transfer values to parameters */
+    *callbacks_ptr = info.callbacks;
+
+    /* Copy udata if it exists */
+    if(info.callbacks.udata != NULL) {
+        HDassert(info.callbacks.udata_copy);
+        if((callbacks_ptr->udata = info.callbacks.udata_copy(info.callbacks.udata)) == 0)
+                HGOTO_ERROR(H5E_PLIST, H5E_CANTSET, FAIL, "can't copy udata")
+    } /* end if */
+
+done:
+    FUNC_LEAVE_API(ret_value)
+} /* end H5Pget_file_image_callbacks() */
+
+
+/*-------------------------------------------------------------------------
+ * Function: H5P_file_image_info_del
+ *
+ * Purpose:     Delete callback for the file image info property, called
+ *              when the property is deleted from the plist. The buffer
+ *              and udata may need to be freed, possibly using their 
+ *              respective callbacks so the default free won't work.
+ *
+ * Return:      Non-negative on success/Negative on failure
+ *
+ * Programmer:  Jacob Gruber
+ *              Thurday, August 11, 2011
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5P_file_image_info_del(hid_t UNUSED prop_id, const char UNUSED *name, size_t UNUSED size, void *value)
+{
+    H5FD_file_image_info_t info;        /* Image info struct */
+    herr_t ret_value = SUCCEED;         /* Return value */
+
+    FUNC_ENTER_NOAPI_NOINIT
+
+    if(value) {
+        info = *(H5FD_file_image_info_t *)value;
+
+        /* verify file image field consistancy */
+        HDassert(((info.buffer != NULL) && (info.size > 0)) || 
+                 ((info.buffer == NULL) && (info.size == 0)));
+
+        if(info.buffer && info.size > 0) {
+            /* Free buffer */
+            if(info.callbacks.image_free) {
+                if(info.callbacks.image_free(info.buffer, H5FD_FILE_IMAGE_OP_PROPERTY_LIST_CLOSE, info.callbacks.udata) < 0)
+		    HGOTO_ERROR(H5E_RESOURCE, H5E_CANTFREE, FAIL, "image_free callback failed")
+            } /* end if */
+            else
+                free(info.buffer);
+        } /* end if */
+
+        /* Free udata if it exists */
+        if(info.callbacks.udata) {
+            if(NULL == info.callbacks.udata_free)
+                HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "udata_free not defined")
+
+            if(info.callbacks.udata_free(info.callbacks.udata) < 0)
+	        HGOTO_ERROR(H5E_RESOURCE, H5E_CANTFREE, FAIL, "udata_free callback failed")
+        } /* end if */
+    } /* end if */
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5P_file_image_info_del() */
+
+
+/*-------------------------------------------------------------------------
+ * Function: H5P_file_image_info_copy
+ *
+ * Purpose:     Copy callback for the file image info property. The buffer
+ *              and udata may need to be copied, possibly using their 
+ *              respective callbacks so the default copy won't work.
+ *
+ * Return:      Non-negative on success/Negative on failure
+ *
+ * Programmer:  Jacob Gruber
+ *              Thurday, August 11, 2011
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5P_file_image_info_copy(const char UNUSED *name, size_t UNUSED size, void *value)
+{
+    H5FD_file_image_info_t *info;       /* Image info struct */
+    herr_t ret_value = SUCCEED;         /* Return value */
+
+    FUNC_ENTER_NOAPI_NOINIT
+
+    if(value) {
+        info = (H5FD_file_image_info_t *)value;
+
+        /* verify file image field consistancy */
+        HDassert(((info->buffer != NULL) && (info->size > 0)) || 
+                 ((info->buffer == NULL) && (info->size == 0)));
+
+        if(info->buffer && info->size > 0) {
+            void *old_buffer;            /* Pointer to old image buffer */
+
+            /* Store the old buffer */
+            old_buffer = info->buffer;
+
+            /* Allocate new buffer */
+            if(info->callbacks.image_malloc) {
+                if(NULL == (info->buffer = info->callbacks.image_malloc(info->size,
+                        H5FD_FILE_IMAGE_OP_PROPERTY_LIST_COPY, info->callbacks.udata)))
+                    HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, FAIL, "image malloc callback failed")
+            } /* end if */
+            else {
+                if(NULL == (info->buffer = H5MM_malloc(info->size)))
+                    HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, FAIL, "unable to allocate memory block")
+            } /* end else */
+            
+            /* Copy data to new buffer */
+            if(info->callbacks.image_memcpy) {
+                if(info->buffer != info->callbacks.image_memcpy(info->buffer, old_buffer, 
+			info->size, H5FD_FILE_IMAGE_OP_PROPERTY_LIST_COPY, 
+			info->callbacks.udata))
+		    HGOTO_ERROR(H5E_RESOURCE, H5E_CANTCOPY, FAIL, "image_memcpy callback failed")
+            } /* end if */
+	    else
+                HDmemcpy(info->buffer, old_buffer, info->size);
+        } /* end if */
+    } /* end if */
+
+    /* Copy udata if it exists */
+    if(info->callbacks.udata) {
+        void *old_udata = info->callbacks.udata;
+
+        if(NULL == info->callbacks.udata_copy)
+            HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "udata_copy not defined")
+
+        info->callbacks.udata = info->callbacks.udata_copy(old_udata);
+    } /* end if */
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5P_file_image_info_copy() */
+
+
+/*-------------------------------------------------------------------------
+ * Function: H5P_file_image_info_close
+ *
+ * Purpose:     Close callback for the file image info property. The buffer
+ *              and udata may need to be freed, possibly using their 
+ *              respective callbacks so the standard free won't work.
+ *
+ * Return:      Non-negative on success/Negative on failure
+ *
+ * Programmer:  Jacob Gruber
+ *              Thurday, August 11, 2011
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5P_file_image_info_close(const char UNUSED *name, size_t UNUSED size, void *value)
+{
+    H5FD_file_image_info_t info;        /* Image info struct */
+    herr_t ret_value = SUCCEED;         /* Return value */
+
+    FUNC_ENTER_NOAPI_NOINIT
+
+    if(value) {
+        info = *(H5FD_file_image_info_t *)value;
+             
+        if(info.buffer != NULL && info.size > 0) { 
+            /* Free buffer */
+            if(info.callbacks.image_free) {
+                if(info.callbacks.image_free(info.buffer, H5FD_FILE_IMAGE_OP_PROPERTY_LIST_CLOSE,
+                        info.callbacks.udata) < 0)
+		    HGOTO_ERROR(H5E_RESOURCE, H5E_CANTFREE, FAIL, "image_free callback failed")
+            } /* end if */
+            else
+                H5MM_xfree(info.buffer);
+        } /* end if */
+    } /* end if */
+
+    /* Free udata if it exists */
+    if(info.callbacks.udata) {
+        if(NULL == info.callbacks.udata_free)
+            HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "udata_free not defined")
+        if(info.callbacks.udata_free(info.callbacks.udata) < 0)
+            HGOTO_ERROR(H5E_RESOURCE, H5E_CANTFREE, FAIL, "udata_free callback failed")
+    } /* end if */
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5P_file_image_info_close() */
diff --git a/src/H5Pint.c b/src/H5Pint.c
index 08b8af6..46a06a0 100644
--- a/src/H5Pint.c
+++ b/src/H5Pint.c
@@ -51,6 +51,7 @@
 typedef struct {
     const H5P_genclass_t *parent;       /* Pointer to parent class */
     const char *name;                   /* Pointer to name to check */
+    H5P_genclass_t *new_class;          /* Pointer to class during path traversal */
 } H5P_check_class_t;
 
 
@@ -1358,11 +1359,11 @@ H5P_access_class(H5P_genclass_t *pclass, H5P_class_mod_t mod)
 
 /*--------------------------------------------------------------------------
  NAME
-    H5P_check_class
+    H5P_open_class_path_cb
  PURPOSE
     Internal callback routine to check for duplicated names in parent class.
  USAGE
-    int H5P_check_class(obj, id, key)
+    int H5P_open_class_path_cb(obj, id, key)
         H5P_genclass_t *obj;    IN: Pointer to class
         hid_t id;               IN: ID of object being looked at
         const void *key;        IN: Pointer to information used to compare
@@ -1378,27 +1379,29 @@ H5P_access_class(H5P_genclass_t *pclass, H5P_class_mod_t mod)
  REVISION LOG
 --------------------------------------------------------------------------*/
 static int
-H5P_check_class(void *_obj, hid_t UNUSED id, void *_key)
+H5P_open_class_path_cb(void *_obj, hid_t UNUSED id, void *_key)
 {
-    H5P_genclass_t *obj=(H5P_genclass_t *)_obj; /* Pointer to the class for this ID */
-    const H5P_check_class_t *key=(const H5P_check_class_t *)_key; /* Pointer to key information for comparison */
-    int ret_value=0;    /* Return value */
+    H5P_genclass_t *obj = (H5P_genclass_t *)_obj; /* Pointer to the class for this ID */
+    H5P_check_class_t *key = (H5P_check_class_t *)_key; /* Pointer to key information for comparison */
+    int ret_value = 0;    /* Return value */
 
     FUNC_ENTER_NOAPI_NOINIT_NOERR
 
     HDassert(obj);
-    HDassert(H5I_GENPROP_CLS==H5I_get_type(id));
+    HDassert(H5I_GENPROP_CLS == H5I_get_type(id));
     HDassert(key);
 
     /* Check if the class object has the same parent as the new class */
-    if(obj->parent==key->parent) {
+    if(obj->parent == key->parent) {
         /* Check if they have the same name */
-        if(HDstrcmp(obj->name,key->name)==0)
-            ret_value=1;        /* Indicate a match */
+        if(HDstrcmp(obj->name, key->name) == 0) {
+            key->new_class = obj;
+            ret_value = 1;        /* Indicate a match */
+        } /* end if */
     } /* end if */
 
     FUNC_LEAVE_NOAPI(ret_value)
-} /* end H5P_check_class() */
+} /* end H5P_open_class_path_cb() */
 
 
 /*--------------------------------------------------------------------------
@@ -4555,8 +4558,8 @@ H5P_open_class_path(const char *path)
     char *curr_name;            /* Pointer to current component of path name */
     char *delimit;              /* Pointer to path delimiter during traversal */
     H5P_genclass_t *curr_class; /* Pointer to class during path traversal */
-    H5P_genclass_t *ret_value;  /* Return value */
     H5P_check_class_t check_info;   /* Structure to hold the information for checking duplicate names */
+    H5P_genclass_t *ret_value;  /* Return value */
 
     FUNC_ENTER_NOAPI_NOINIT
 
@@ -4569,20 +4572,24 @@ H5P_open_class_path(const char *path)
     /* Find the generic property class with this full path */
     curr_name = tmp_path;
     curr_class = NULL;
-    while((delimit=HDstrchr(curr_name,'/'))!=NULL) {
+    while(NULL != (delimit = HDstrchr(curr_name, '/'))) {
         /* Change the delimiter to terminate the string */
-        *delimit='\0';
+        *delimit = '\0';
 
         /* Set up the search structure */
-        check_info.parent=curr_class;
-        check_info.name=curr_name;
+        check_info.parent = curr_class;
+        check_info.name = curr_name;
+        check_info.new_class = NULL;
 
         /* Find the class with this name & parent by iterating over the open classes */
-        if(NULL == (curr_class = (H5P_genclass_t *)H5I_search(H5I_GENPROP_CLS, H5P_check_class, &check_info, FALSE)))
-            HGOTO_ERROR(H5E_PLIST, H5E_NOTFOUND, NULL, "can't locate class")
+        if(H5I_iterate(H5I_GENPROP_CLS, H5P_open_class_path_cb, &check_info, FALSE) < 0)
+	    HGOTO_ERROR(H5E_PLIST, H5E_BADITER, NULL, "can't iterate over classes")
+	else if(NULL == check_info.new_class)
+	    HGOTO_ERROR(H5E_PLIST, H5E_NOTFOUND, NULL, "can't locate class")
 
         /* Advance the pointer in the path to the start of the next component */
-        curr_name=delimit+1;
+        curr_class = check_info.new_class;
+        curr_name = delimit + 1;
     } /* end while */
 
     /* Should be pointing to the last component in the path name now... */
@@ -4590,13 +4597,16 @@ H5P_open_class_path(const char *path)
     /* Set up the search structure */
     check_info.parent = curr_class;
     check_info.name = curr_name;
+    check_info.new_class = NULL;
 
     /* Find the class with this name & parent by iterating over the open classes */
-    if(NULL == (curr_class = (H5P_genclass_t *)H5I_search(H5I_GENPROP_CLS, H5P_check_class, &check_info, FALSE)))
+    if(H5I_iterate(H5I_GENPROP_CLS, H5P_open_class_path_cb, &check_info, FALSE) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_BADITER, NULL, "can't iterate over classes")
+    else if(NULL == check_info.new_class)
         HGOTO_ERROR(H5E_PLIST, H5E_NOTFOUND, NULL, "can't locate class")
 
     /* Copy it */
-    if(NULL == (ret_value = H5P_copy_pclass(curr_class)))
+    if(NULL == (ret_value = H5P_copy_pclass(check_info.new_class)))
         HGOTO_ERROR(H5E_PLIST, H5E_CANTCOPY, NULL, "can't copy property class")
 
 done:
@@ -4604,7 +4614,7 @@ done:
     H5MM_xfree(tmp_path);
 
     FUNC_LEAVE_NOAPI(ret_value)
-}   /* H5P_open_class_path() */
+} /* H5P_open_class_path() */
 
 
 /*--------------------------------------------------------------------------
diff --git a/src/H5Pocpl.c b/src/H5Pocpl.c
index 217d0ba..217d0ba 100755..100644
--- a/src/H5Pocpl.c
+++ b/src/H5Pocpl.c
diff --git a/src/H5Pocpypl.c b/src/H5Pocpypl.c
index af50d80..23f8e4b 100755..100644
--- a/src/H5Pocpypl.c
+++ b/src/H5Pocpypl.c
@@ -35,7 +35,9 @@
 /***********/
 #include "H5private.h"		/* Generic Functions			*/
 #include "H5Eprivate.h"		/* Error handling		  	*/
+#include "H5FLprivate.h"        /* Free Lists                           */
 #include "H5Iprivate.h"		/* IDs			  		*/
+#include "H5MMprivate.h"        /* Memory management                    */
 #include "H5Ppkg.h"		/* Property lists		  	*/
 
 
@@ -47,7 +49,13 @@
 /* Definitions for copy options */
 #define H5O_CPY_OPTION_SIZE			sizeof(unsigned)
 #define H5O_CPY_OPTION_DEF			0
-
+/* Definitions for merge committed dtype list */
+#define H5O_CPY_MERGE_COMM_DT_LIST_SIZE        sizeof(char *)
+#define H5O_CPY_MERGE_COMM_DT_LIST_DEF         NULL
+#define H5O_CPY_MERGE_COMM_DT_LIST_CMP         H5P_ocpy_merge_comm_dt_list_cmp
+/* Definitions for callback function when completing the search for a matching committed datatype from the committed dtype list */
+#define H5O_CPY_MCDT_SEARCH_CB_SIZE           sizeof(H5O_mcdt_cb_info_t)
+#define H5O_CPY_MCDT_SEARCH_CB_DEF            {NULL,NULL} 
 
 /******************/
 /* Local Typedefs */
@@ -63,8 +71,17 @@
 /* Local Prototypes */
 /********************/
 
+/* General routines */
+static H5O_copy_dtype_merge_list_t *H5P_free_merge_comm_dtype_list(H5O_copy_dtype_merge_list_t *dt_list);
+
 /* Property class callbacks */
 static herr_t H5P_ocpy_reg_prop(H5P_genclass_t *pclass);
+static herr_t H5P_ocpy_copy(hid_t dst_plist_id, hid_t src_plist_id,
+    void *copy_data);
+static herr_t H5P_ocpy_close(hid_t ocpypl_id, void *close_data);
+
+/* Property callbacks */
+static int H5P_ocpy_merge_comm_dt_list_cmp(const void *value1, const void *value2, size_t size);
 
 
 /*********************/
@@ -80,9 +97,9 @@ const H5P_libclass_t H5P_CLS_OCPY[1] = {{
     H5P_ocpy_reg_prop,		/* Default property registration routine */
     NULL,		        /* Class creation callback      */
     NULL,		        /* Class creation callback info */
-    NULL,			/* Class copy callback          */
+    H5P_ocpy_copy,		/* Class copy callback          */
     NULL,		        /* Class copy callback info     */
-    NULL,			/* Class close callback         */
+    H5P_ocpy_close,		/* Class close callback         */
     NULL 		        /* Class close callback info    */
 }};
 
@@ -96,6 +113,9 @@ const H5P_libclass_t H5P_CLS_OCPY[1] = {{
 /* Local Variables */
 /*******************/
 
+/* Declare a free list to manage the H5O_copy_dtype_merge_list_t struct */
+H5FL_DEFINE(H5O_copy_dtype_merge_list_t);
+
 
 
 /*-------------------------------------------------------------------------
@@ -109,10 +129,12 @@ const H5P_libclass_t H5P_CLS_OCPY[1] = {{
  *              October 31, 2006
  *-------------------------------------------------------------------------
  */
-herr_t
+static herr_t
 H5P_ocpy_reg_prop(H5P_genclass_t *pclass)
 {
     unsigned ocpy_option = H5O_CPY_OPTION_DEF;  /* Default object copy flags */
+    H5O_copy_dtype_merge_list_t *merge_comm_dtype_list = H5O_CPY_MERGE_COMM_DT_LIST_DEF; /* Default merge committed dtype list */
+    H5O_mcdt_cb_info_t mcdt_cb = H5O_CPY_MCDT_SEARCH_CB_DEF; /* Default callback before searching the global list of committed datatypes at destination */
     herr_t ret_value = SUCCEED;         /* Return value */
 
     FUNC_ENTER_NOAPI(FAIL)
@@ -121,12 +143,222 @@ H5P_ocpy_reg_prop(H5P_genclass_t *pclass)
     if(H5P_register_real(pclass, H5O_CPY_OPTION_NAME, H5O_CPY_OPTION_SIZE, &ocpy_option, NULL, NULL, NULL, NULL, NULL, NULL, NULL) < 0)
          HGOTO_ERROR(H5E_PLIST, H5E_CANTINSERT, FAIL, "can't insert property into class")
 
+    /* Register merge named dtype list property */
+    if(H5P_register_real(pclass, H5O_CPY_MERGE_COMM_DT_LIST_NAME, H5O_CPY_MERGE_COMM_DT_LIST_SIZE, &merge_comm_dtype_list, NULL, NULL, NULL, NULL, NULL, H5O_CPY_MERGE_COMM_DT_LIST_CMP, NULL) < 0)
+         HGOTO_ERROR(H5E_PLIST, H5E_CANTINSERT, FAIL, "can't insert property into class")
+
+    /* Register property for callback when completing the search for a matching named datatype from the named dtype list */
+    if(H5P_register_real(pclass, H5O_CPY_MCDT_SEARCH_CB_NAME, H5O_CPY_MCDT_SEARCH_CB_SIZE, &mcdt_cb, NULL, NULL, NULL, NULL, NULL, NULL, NULL) < 0)
+         HGOTO_ERROR(H5E_PLIST, H5E_CANTINSERT, FAIL, "can't insert property into class")
+
 done:
     FUNC_LEAVE_NOAPI(ret_value)
 } /* end H5P_ocpy_reg_prop() */
 
 
 /*-------------------------------------------------------------------------
+ * Function:       H5P_ocpy_copy
+ *
+ * Purpose:        Callback routine which is called whenever any object
+ *                 copy property list is copied.  This routine copies
+ *                 the properties from the old list to the new list.
+ *
+ * Return:         Success:        Non-negative
+ *                 Failure:        Negative
+ *
+ * Programmer:     Neil Fortner
+ *                 Friday, October 28, 2011
+ *
+ *-------------------------------------------------------------------------
+ */
+/* ARGSUSED */
+static herr_t
+H5P_ocpy_copy(hid_t dst_plist_id, hid_t src_plist_id, void UNUSED *copy_data)
+{
+    H5O_copy_dtype_merge_list_t *src_dt_list, *dst_dt_list = NULL; /* Source & destination merge named datatype lists */
+    H5O_copy_dtype_merge_list_t *dst_dt_list_tail = NULL, *tmp_dt_list = NULL; /* temporary merge named datatype lists */
+    H5P_genplist_t *src_plist;                  /* Pointer to source property list */
+    H5P_genplist_t *dst_plist;                  /* Pointer to destination property list */
+    herr_t         ret_value = SUCCEED;         /* Return value */
+
+    FUNC_ENTER_NOAPI_NOINIT
+
+    /* Verify property list IDs */
+    if(NULL == (dst_plist = (H5P_genplist_t *)H5I_object(dst_plist_id)))
+        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not an object copy property list")
+    if(NULL == (src_plist = (H5P_genplist_t *)H5I_object(src_plist_id)))
+        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not an object copy property list")
+
+    /* Get the merge committed dtype list property from the old property list */
+    if(H5P_get(src_plist, H5O_CPY_MERGE_COMM_DT_LIST_NAME, &src_dt_list) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't get merge named dtype list")
+
+    /* Make copy of merge committed dtype list */
+    while(src_dt_list) {
+        /* Copy src_dt_list */
+        if(NULL == (tmp_dt_list = H5FL_CALLOC(H5O_copy_dtype_merge_list_t)))
+            HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, FAIL, "memory allocation failed")
+        if(NULL == (tmp_dt_list->path = H5MM_strdup(src_dt_list->path)))
+            HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, FAIL, "memory allocation failed")
+
+        /* Add copied node to dest dtype list */
+        if(dst_dt_list_tail) {
+            dst_dt_list_tail->next = tmp_dt_list;
+            dst_dt_list_tail = tmp_dt_list;
+        } /* end if */
+        else {
+            dst_dt_list = tmp_dt_list;
+            dst_dt_list_tail = tmp_dt_list;
+        } /* end else */
+        tmp_dt_list = NULL;
+
+        /* Advance src_dt_list pointer */
+        src_dt_list = src_dt_list->next;
+    } /* end while */
+
+    /* Set the merge named dtype list property for the destination property list
+     */
+    if(H5P_set(dst_plist, H5O_CPY_MERGE_COMM_DT_LIST_NAME, &dst_dt_list) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTSET, FAIL, "can't set merge committed dtype list")
+
+done:
+    if(ret_value < 0) {
+        dst_dt_list = H5P_free_merge_comm_dtype_list(dst_dt_list);
+        if(tmp_dt_list) {
+            tmp_dt_list->path = (char *)H5MM_xfree(tmp_dt_list->path);
+            tmp_dt_list = H5FL_FREE(H5O_copy_dtype_merge_list_t, tmp_dt_list);
+        } /* end if */
+    } /* end if */
+
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5P_ocpy_copy() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:       H5P_ocpy_close
+ *
+ * Purpose:        Callback routine which is called whenever any object copy
+ *                 property list is closed.  This routine performs any generic
+ *                 cleanup needed on the properties the library put into the
+ *                 list.
+ *
+ * Return:         Success:        Non-negative
+ *                 Failure:        Negative
+ *
+ * Programmer:     Neil Fortner
+ *                 Friday, October 28, 2011
+ *
+ *-------------------------------------------------------------------------
+ */
+/* ARGSUSED */
+static herr_t
+H5P_ocpy_close(hid_t ocpypl_id, void UNUSED *close_data)
+{
+    H5O_copy_dtype_merge_list_t *dt_list;       /* Merge named datatype list */
+    H5P_genplist_t *plist;                      /* Property list */
+    herr_t         ret_value = SUCCEED;         /* Return value */
+
+    FUNC_ENTER_NOAPI_NOINIT
+
+    /* Check arguments */
+    if(NULL == (plist = (H5P_genplist_t *)H5I_object(ocpypl_id)))
+        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not an object copy property list")
+
+    /* Get the merge named dtype list property from the old property list */
+    if(H5P_get(plist, H5O_CPY_MERGE_COMM_DT_LIST_NAME, &dt_list) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't get merge named dtype list")
+
+    /* Free the merge named dtype list */
+    dt_list = H5P_free_merge_comm_dtype_list(dt_list);
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5P_ocpy_close() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:       H5P_ocpy_merge_comm_dt_list_cmp
+ *
+ * Purpose:        Callback routine which is called whenever the merge
+ *                 named dtype property in the object copy property list
+ *                 is compared.
+ *
+ * Return:         positive if VALUE1 is greater than VALUE2, negative if
+ *                      VALUE2 is greater than VALUE1 and zero if VALUE1 and
+ *                      VALUE2 are equal.
+ *
+ * Programmer:     Neil Fortner
+ *                 Friday, October 28, 2011
+ *
+ *-------------------------------------------------------------------------
+ */
+static int
+H5P_ocpy_merge_comm_dt_list_cmp(const void *_dt_list1, const void *_dt_list2,
+    size_t UNUSED size)
+{
+    const H5O_copy_dtype_merge_list_t *dt_list1 = *(H5O_copy_dtype_merge_list_t * const *)_dt_list1,     /* Create local aliases for values */
+        *dt_list2 = *(H5O_copy_dtype_merge_list_t * const *)_dt_list2;
+    herr_t ret_value = 0;       /* Return value */
+
+    FUNC_ENTER_NOAPI_NOINIT
+
+    /* Sanity check */
+    HDassert(_dt_list1);
+    HDassert(_dt_list2);
+    HDassert(size == sizeof(H5O_copy_dtype_merge_list_t *));
+
+    /* Walk through the lists, comparing each path.  For the lists to be the
+     * same, the paths must be in the same order. */
+    while(dt_list1 && dt_list2) {
+        /* Compare paths */
+        ret_value = HDstrcmp(dt_list1->path, dt_list2->path);
+        if(ret_value != 0) HGOTO_DONE(ret_value)
+
+        /* Advance to next node */
+        dt_list1 = dt_list1->next;
+        dt_list2 = dt_list2->next;
+    } /* end while */
+
+    /* Check if one list is longer than the other */
+    if(dt_list1) HGOTO_DONE(1)
+    if(dt_list2) HGOTO_DONE(-1)
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5P_ocpy_merge_comm_dt_list_cmp() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:    H5P_free_merge_comm_dtype_list
+ *
+ * Purpose:     Frees the provided merge named dtype list
+ *
+ * Return:      NULL
+ *
+ * Programmer:  Neil Fortner
+ *              October 27, 2011
+ *-------------------------------------------------------------------------
+ */
+static H5O_copy_dtype_merge_list_t *
+H5P_free_merge_comm_dtype_list(H5O_copy_dtype_merge_list_t *dt_list)
+{
+    H5O_copy_dtype_merge_list_t *tmp_node;
+
+    FUNC_ENTER_NOAPI_NOINIT
+
+    /* Free the list */
+    while(dt_list) {
+        tmp_node = dt_list->next;
+        (void)H5MM_xfree(dt_list->path);
+        (void)H5FL_FREE(H5O_copy_dtype_merge_list_t, dt_list);
+        dt_list = tmp_node;
+    } /* end while */
+
+    FUNC_LEAVE_NOAPI(NULL);
+} /* H5P_free_merge_comm_dtype_list */
+
+
+/*-------------------------------------------------------------------------
  * Function:    H5Pset_copy_object
  *
  * Purpose:     Set properties when copying an object (group, dataset, and datatype)
@@ -207,3 +439,210 @@ done:
     FUNC_LEAVE_API(ret_value)
 } /* end H5Pget_copy_object() */
 
+
+/*-------------------------------------------------------------------------
+ * Function:    H5Padd_merge_committed_dtype_path
+ *
+ * Purpose:     Adds path to the list of paths to search first in the
+ *              target file when merging committed datatypes during H5Ocopy
+ *              (i.e. when using the H5O_COPY_MERGE_COMMITTED_DTYPE_FLAG flag
+ *              as set by H5Pset_copy_object).  If the source named
+ *              dataype is not found in the list of paths created by this
+ *              function, the entire file will be searched.
+ *
+ * Usage:       H5Padd_merge_committed_dtype_path(plist_id, path)
+ *              hid_t plist_id;                 IN: Property list to copy object
+ *              const char *path;               IN: Path to add to list
+ *
+ * Return:      Non-negative on success/Negative on failure
+ *
+ * Programmer:  Neil Fortner
+ *              October 27, 2011
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5Padd_merge_committed_dtype_path(hid_t plist_id, const char *path)
+{
+    H5P_genplist_t *plist;      /* Property list pointer */
+    H5O_copy_dtype_merge_list_t *old_list; 	/* Merge committed dtype list currently present */
+    H5O_copy_dtype_merge_list_t *new_obj = NULL; /* New object to add to list */
+    herr_t ret_value = SUCCEED; /* Return value */
+
+    FUNC_ENTER_API(FAIL)
+    H5TRACE2("e", "i*s", plist_id, path);
+
+    /* Check parameters */
+    if(!path)
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "no path specified")
+
+    /* Get the plist structure */
+    if(NULL == (plist = H5P_object_verify(plist_id, H5P_OBJECT_COPY)))
+        HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, FAIL, "can't find object for ID")
+
+    /* Get dtype list */
+    if(H5P_get(plist, H5O_CPY_MERGE_COMM_DT_LIST_NAME, &old_list) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't get merge named dtype list")
+
+    /* Add the new path to the list */
+    if(NULL == (new_obj = H5FL_CALLOC(H5O_copy_dtype_merge_list_t)))
+        HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, FAIL, "memory allocation failed")
+    if(NULL == (new_obj->path = H5MM_strdup(path)))
+        HGOTO_ERROR(H5E_RESOURCE, H5E_NOSPACE, FAIL, "memory allocation failed")
+    new_obj->next = old_list;
+
+    /* Update the list stored in the property list */
+    if(H5P_set(plist, H5O_CPY_MERGE_COMM_DT_LIST_NAME, &new_obj) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTSET, FAIL, "can't set merge named dtype list")
+
+done:
+    if(ret_value < 0)
+        if(new_obj) {
+            new_obj->path = (char *)H5MM_xfree(new_obj->path);
+            new_obj = H5FL_FREE(H5O_copy_dtype_merge_list_t, new_obj);
+        } /* end if */
+
+    FUNC_LEAVE_API(ret_value)
+} /* end H5Padd_merge_committed_dtype_path() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:    H5Pfree_merge_committed_dtype_paths
+ *
+ * Purpose:     Frees and clears the list of paths created by
+ *              H5Padd_merge_committed_dtype_path.  A new list may then be
+ *              created by calling H5Padd_merge_committed_dtype_path again.
+ *
+ * Usage:       H5Pfree_merge_committed_dtype_paths(plist_id)
+ *              hid_t plist_id;                 IN: Property list to copy object
+ *
+ * Return:      Non-negative on success/Negative on failure
+ *
+ * Programmer:  Neil Fortner
+ *              October 27, 2011
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5Pfree_merge_committed_dtype_paths(hid_t plist_id)
+{
+    H5P_genplist_t *plist;      /* Property list pointer */
+    H5O_copy_dtype_merge_list_t *dt_list; /* Merge committed dtype list currently present */
+    herr_t ret_value = SUCCEED; /* Return value */
+
+    FUNC_ENTER_API(FAIL)
+    H5TRACE1("e", "i", plist_id);
+
+    /* Get the plist structure */
+    if(NULL == (plist = H5P_object_verify(plist_id, H5P_OBJECT_COPY)))
+        HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, FAIL, "can't find object for ID")
+
+    /* Get dtype list */
+    if(H5P_get(plist, H5O_CPY_MERGE_COMM_DT_LIST_NAME, &dt_list) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't get merge committed dtype list")
+
+    /* Free dtype list */
+    dt_list = H5P_free_merge_comm_dtype_list(dt_list);
+
+    /* Update the list stored in the property list (to NULL) */
+    if(H5P_set(plist, H5O_CPY_MERGE_COMM_DT_LIST_NAME, &dt_list) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTSET, FAIL, "can't set merge committed dtype list")
+
+done:
+    FUNC_LEAVE_API(ret_value)
+} /* end H5Pfree_merge_committed_dtype_paths() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:    H5Pset_mcdt_search_cb
+ *
+ * Purpose:     Set the callback function when a matching committed datatype is not found
+ *		from the list of paths stored in the object copy property list.
+ * 		H5Ocopy will invoke this callback before searching all committed datatypes
+ *		at destination.
+ *
+ * Usage:       H5Pset_mcdt_search_cb(plist_id, H5O_mcdt_search_cb_t func, void *op_data)
+ *              hid_t plist_id;                 IN: Property list to copy object
+ *              H5O_mcdt_search_cb_t func;      IN: The callback function
+ *              void *op_data;      		IN: The user data
+ *
+ * Return:      Non-negative on success/Negative on failure
+ *
+ * Programmer:  Vailin Choi; November 28, 2011
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5Pset_mcdt_search_cb(hid_t plist_id, H5O_mcdt_search_cb_t func, void *op_data)
+{
+    H5P_genplist_t *plist;      	/* Property list pointer */
+    H5O_mcdt_cb_info_t cb_info;		/* Callback info struct */
+    herr_t ret_value = SUCCEED; 	/* Return value */
+
+    FUNC_ENTER_API(FAIL)
+    H5TRACE3("e", "ix*x", plist_id, func, op_data);
+
+    /* Check if the callback function is NULL and the user data is non-NULL.
+     * This is almost certainly an error as the user data will not be used. */
+    if(!func && op_data)
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "callback is NULL while user data is not")
+
+    /* Get the plist structure */
+    if(NULL == (plist = H5P_object_verify(plist_id, H5P_OBJECT_COPY)))
+        HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, FAIL, "can't find object for ID")
+
+     /* Populate the callback info struct */
+    cb_info.func = func;
+    cb_info.user_data = op_data;
+
+    /* Set callback info */
+    if(H5P_set(plist, H5O_CPY_MCDT_SEARCH_CB_NAME, &cb_info) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTSET, FAIL, "can't set callback info")
+
+done:
+    FUNC_LEAVE_API(ret_value)
+} /* end H5Pset_mcdt_search_cb() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:    H5Pget_mcdt_search_cb
+ *
+ * Purpose:     Retrieves the callback function and user data from the specified 
+ *		object copy property list.
+ *
+ * Usage:       H5Pget_mcdt_search_cb(plist_id, H5O_mcdt_search_cb_t *func, void **op_data)
+ *              hid_t plist_id;                 IN: Property list to copy object
+ *		H5O_mcdt_search_cb_t *func;	OUT: The callback function
+ *		void **op_data;			OUT: The user data
+ *
+ * Return:      Non-negative on success/Negative on failure
+ *
+ * Programmer:  Vailin Choi; November 29, 2011
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5Pget_mcdt_search_cb(hid_t plist_id, H5O_mcdt_search_cb_t *func, void **op_data)
+{
+    H5P_genplist_t *plist;      /* Property list pointer */
+    H5O_mcdt_cb_info_t cb_info;	/* Callback info struct */
+    herr_t ret_value = SUCCEED; /* Return value */
+
+    FUNC_ENTER_API(FAIL)
+    H5TRACE3("e", "i*x**x", plist_id, func, op_data);
+
+    /* Get the plist structure */
+    if(NULL == (plist = H5P_object_verify(plist_id, H5P_OBJECT_COPY)))
+        HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, FAIL, "can't find object for ID")
+
+    /* Get callback info */
+    if(H5P_get(plist, H5O_CPY_MCDT_SEARCH_CB_NAME, &cb_info) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't get callback info")
+    
+    if(func)
+	*func = cb_info.func;
+
+    if(op_data)
+	*op_data = cb_info.user_data;
+
+done:
+    FUNC_LEAVE_API(ret_value)
+} /* end H5Pget_mcdt_search_cb() */
+
diff --git a/src/H5Ppublic.h b/src/H5Ppublic.h
index 4c812cc..6cba897 100644
--- a/src/H5Ppublic.h
+++ b/src/H5Ppublic.h
@@ -30,6 +30,7 @@
 #include "H5FDpublic.h"
 #include "H5Ipublic.h"
 #include "H5Lpublic.h"
+#include "H5Opublic.h"
 #include "H5MMpublic.h"
 #include "H5Tpublic.h"
 #include "H5Zpublic.h"
@@ -326,6 +327,12 @@ H5_DLL herr_t H5Pget_libver_bounds(hid_t plist_id, H5F_libver_t *low,
     H5F_libver_t *high);
 H5_DLL herr_t H5Pset_elink_file_cache_size(hid_t plist_id, unsigned efc_size);
 H5_DLL herr_t H5Pget_elink_file_cache_size(hid_t plist_id, unsigned *efc_size);
+H5_DLL herr_t H5Pset_file_image(hid_t fapl_id, void *buf_ptr, size_t buf_len);
+H5_DLL herr_t H5Pget_file_image(hid_t fapl_id, void **buf_ptr_ptr, size_t *buf_len_ptr);
+H5_DLL herr_t H5Pset_file_image_callbacks(hid_t fapl_id,
+       H5FD_file_image_callbacks_t *callbacks_ptr);
+H5_DLL herr_t H5Pget_file_image_callbacks(hid_t fapl_id,
+       H5FD_file_image_callbacks_t *callbacks_ptr);
 
 /* Dataset creation property list (DCPL) routines */
 H5_DLL herr_t H5Pset_layout(hid_t plist_id, H5D_layout_t layout);
@@ -432,6 +439,10 @@ H5_DLL herr_t H5Pget_elink_cb(hid_t lapl_id, H5L_elink_traverse_t *func, void **
 /* Object copy property list (OCPYPL) routines */
 H5_DLL herr_t H5Pset_copy_object(hid_t plist_id, unsigned crt_intmd);
 H5_DLL herr_t H5Pget_copy_object(hid_t plist_id, unsigned *crt_intmd /*out*/);
+H5_DLL herr_t H5Padd_merge_committed_dtype_path(hid_t plist_id, const char *path);
+H5_DLL herr_t H5Pfree_merge_committed_dtype_paths(hid_t plist_id);
+H5_DLL herr_t H5Pset_mcdt_search_cb(hid_t plist_id, H5O_mcdt_search_cb_t func, void *op_data);
+H5_DLL herr_t H5Pget_mcdt_search_cb(hid_t plist_id, H5O_mcdt_search_cb_t *func, void **op_data);
 
 /* Symbols defined for compatibility with previous versions of the HDF5 API.
  *
diff --git a/src/H5SM.c b/src/H5SM.c
index 8c00d34..62efb50 100755..100644
--- a/src/H5SM.c
+++ b/src/H5SM.c
@@ -1099,7 +1099,7 @@ H5SM_try_share(H5F_t *f, hid_t dxpl_id, H5O_t *open_oh, unsigned defer_flags,
     /* Set flags if this message was "written" without error and wasn't a
      * 'defer' attempt; it is now either fully shared or "shareable".
      */
-    if(mesg_flags && !(defer_flags & H5SM_DEFER)) {
+    if(mesg_flags) {
         if(((H5O_shared_t *)mesg)->type == H5O_SHARE_TYPE_HERE)
             *mesg_flags |= H5O_MSG_FLAG_SHAREABLE;
         else {
@@ -1109,7 +1109,8 @@ H5SM_try_share(H5F_t *f, hid_t dxpl_id, H5O_t *open_oh, unsigned defer_flags,
     } /* end if */
 
 done:
-    HDassert(!ret_value || ((H5O_shared_t *)mesg)->type == H5O_SHARE_TYPE_HERE
+    HDassert((ret_value != TRUE)
+            || ((H5O_shared_t *)mesg)->type == H5O_SHARE_TYPE_HERE
             || ((H5O_shared_t *)mesg)->type == H5O_SHARE_TYPE_SOHM);
 #ifndef NDEBUG
     /* If we previously deferred this operation, make sure the saved message
diff --git a/src/H5SMbtree2.c b/src/H5SMbtree2.c
index daa1e4f..daa1e4f 100755..100644
--- a/src/H5SMbtree2.c
+++ b/src/H5SMbtree2.c
diff --git a/src/H5SMpkg.h b/src/H5SMpkg.h
index 68dc484..68dc484 100755..100644
--- a/src/H5SMpkg.h
+++ b/src/H5SMpkg.h
diff --git a/src/H5SMprivate.h b/src/H5SMprivate.h
index d072434..d072434 100755..100644
--- a/src/H5SMprivate.h
+++ b/src/H5SMprivate.h
diff --git a/src/H5T.c b/src/H5T.c
index 392228b..b27b152 100644
--- a/src/H5T.c
+++ b/src/H5T.c
@@ -1450,7 +1450,8 @@ H5T_term_interface(void)
 	H5T_g.asoft = 0;
 
 	/* Unlock all datatypes, then free them */
-	H5I_search(H5I_DATATYPE, H5T_unlock_cb, NULL, FALSE);
+	/* note that we are ignoring the return value from H5I_iterate() */
+	H5I_iterate(H5I_DATATYPE, H5T_unlock_cb, NULL, FALSE);
 	H5I_dec_type_ref(H5I_DATATYPE);
 
         /* Reset all the datatype IDs */
diff --git a/src/H5Toh.c b/src/H5Toh.c
index 5878075..be853f1 100644
--- a/src/H5Toh.c
+++ b/src/H5Toh.c
@@ -77,7 +77,8 @@ const H5O_obj_class_t H5O_OBJ_DATATYPE[1] = {{
     H5O_dtype_open, 		/* open an object of this class */
     H5O_dtype_create, 		/* create an object of this class */
     H5O_dtype_get_oloc,		/* get an object header location for an object */
-    NULL 			/* get the index & heap info for an object */
+    NULL,			/* get the index & heap info for an object */
+    NULL 			/* flush an opened object of this class */
 }};
 
 
diff --git a/src/H5VL.c b/src/H5VL.c
index 293711f..f821463 100644
--- a/src/H5VL.c
+++ b/src/H5VL.c
@@ -1920,8 +1920,7 @@ H5VL_attr_create(hid_t uid, const char *name, hid_t acpl_id, hid_t aapl_id)
     id_type = H5I_get_type(uid);
     /* Check id */
     if(H5I_FILE_PUBLIC != id_type && H5I_GROUP_PUBLIC != id_type &&
-       H5I_DATASET_PUBLIC != id_type && H5I_DATATYPE_PUBLIC !=  id_type &&
-       H5I_ATTR_PUBLIC != id_type)
+       H5I_DATASET_PUBLIC != id_type && H5I_DATATYPE_PUBLIC != id_type)
 	HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not a user ID")
 
     /* get the ID struct */
diff --git a/src/H5err.txt b/src/H5err.txt
index 71d27a6..b4cb28b 100644
--- a/src/H5err.txt
+++ b/src/H5err.txt
@@ -220,6 +220,7 @@ MINOR, DSPACE, H5E_CANTCOMPARE, Can't compare objects
 MINOR, PLIST, H5E_CANTGET, Can't get value
 MINOR, PLIST, H5E_CANTSET, Can't set value
 MINOR, PLIST, H5E_DUPCLASS, Duplicate class name in parent class
+MINOR, PLIST, H5E_SETDISALLOWED, Disallowed operation
 
 # Link errors
 MINOR, LINK, H5E_TRAVERSE, Link traversal failure
diff --git a/src/H5private.h b/src/H5private.h
index 77ceaca..0bb8e3e 100644
--- a/src/H5private.h
+++ b/src/H5private.h
@@ -151,7 +151,9 @@
 
 
 #ifdef H5_HAVE_WIN32_API
+/* The following two defines must be before any windows headers are included */
 #define WIN32_LEAN_AND_MEAN    /* Exclude rarely-used stuff from Windows headers */
+#define NOGDI                  /* Exclude Graphic Display Interface macros */
 
 #ifdef H5_HAVE_WINSOCK_H
 #include <winsock2.h>
diff --git a/src/H5public.h b/src/H5public.h
index 1f44ff3..e36c0eb 100644
--- a/src/H5public.h
+++ b/src/H5public.h
@@ -75,10 +75,10 @@ extern "C" {
 /* Version numbers */
 #define H5_VERS_MAJOR	1	/* For major interface/format changes  	     */
 #define H5_VERS_MINOR	9	/* For minor interface/format changes  	     */
-#define H5_VERS_RELEASE	112	/* For tweaks, bug-fixes, or development     */
+#define H5_VERS_RELEASE	114	/* For tweaks, bug-fixes, or development     */
 #define H5_VERS_SUBRELEASE ""	/* For pre-releases like snap0       */
 				/* Empty string for real releases.           */
-#define H5_VERS_INFO    "HDF5 library version: 1.9.112"      /* Full version string */
+#define H5_VERS_INFO    "HDF5 library version: 1.9.114"      /* Full version string */
 
 #define H5check()	H5check_version(H5_VERS_MAJOR,H5_VERS_MINOR,	      \
 				        H5_VERS_RELEASE)
diff --git a/src/H5win32defs.h b/src/H5win32defs.h
index 5f886d1..e9b87625 100644
--- a/src/H5win32defs.h
+++ b/src/H5win32defs.h
@@ -33,9 +33,7 @@ typedef __int64             h5_stat_size_t;
 #define HDdup(F)            _dup(F)
 #define HDfdopen(N,S)       _fdopen(N,S)
 #define HDfileno(F)         _fileno(F)
-#define HDfseek(F,O,W)      _fseeki64(F,O,W)
 #define HDfstat(F,B)        _fstati64(F,B)
-#define HDftruncate(F,L)    _chsize_s(F,L)
 #define HDisatty(F)         _isatty(F)
 #define HDgetcwd(S,Z)       _getcwd(S,Z)
 #define HDgetdcwd(D,S,Z)    _getdcwd(D,S,Z)
@@ -91,4 +89,8 @@ struct timezone {
  * type cannot be cast as a ulong like other systems. */
 #define HDpthread_self_ulong() ((unsigned long)GetCurrentThreadId())
 
+#ifndef H5_HAVE_MINGW
+#define HDftruncate(F,L)    _chsize_s(F,L)
+#define HDfseek(F,O,W)      _fseeki64(F,O,W)
+#endif
 #endif /* H5_HAVE_WIN32_API */
diff --git a/src/Makefile.am b/src/Makefile.am
index fad0241..fad0241 100755..100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
diff --git a/src/Makefile.in b/src/Makefile.in
index c9c1089..6efe7c4 100644
--- a/src/Makefile.in
+++ b/src/Makefile.in
@@ -485,7 +485,7 @@ CHECK_CLEANFILES = *.chkexe *.chklog *.clog
 # Add libtool shared library version numbers to the HDF5 library
 # See libtool versioning documentation online.
 LT_VERS_INTERFACE = 6
-LT_VERS_REVISION = 102
+LT_VERS_REVISION = 104
 LT_VERS_AGE = 0
 H5detect_CFLAGS = -g $(AM_CFLAGS)
 
diff --git a/src/hdf5.lnt b/src/hdf5.lnt
index 1d02039..1d02039 100755..100644
--- a/src/hdf5.lnt
+++ b/src/hdf5.lnt