[svn-r17243] Description:

	Refactor how the layout message is created/written/read in the
dataset's object header.

Tested on:
        FreeBSD/32 6.3 (duty) in debug mode
        FreeBSD/64 6.3 (liberty) w/C++ & FORTRAN, in debug mode
        Linux/32 2.6 (jam) w/PGI compilers, w/C++ & FORTRAN, w/threadsafe,
                                in debug mode
        Linux/64-amd64 2.6 (smirom) w/Intel compilers w/default API=1.6.x,
                                w/C++ & FORTRAN, in production mode
        Solaris/32 2.10 (linew) w/deprecated symbols disabled, w/C++ & FORTRAN,
                                w/szip filter, in production mode
        Linux/64-ia64 2.6 (cobalt) w/Intel compilers, w/C++ & FORTRAN,
                                in production mode
        Linux/64-ia64 2.4 (tg-login3) w/parallel, w/FORTRAN, in debug mode
        Linux/64-amd64 2.6 (abe) w/parallel, w/FORTRAN, in production mode
        Mac OS X/32 10.5.7 (amazon) in debug mode
        Mac OS X/32 10.5.7 (amazon) w/C++ & FORTRAN, w/threadsafe,
                                in production mode

9 files changed, 607 insertions, 327 deletions

diff --git a/src/H5Dchunk.c b/src/H5Dchunk.c
index 9e6e540..51c14e6 100644
--- a/src/H5Dchunk.c
+++ b/src/H5Dchunk.c
@@ -181,6 +181,7 @@ static herr_t H5D_chunk_read(H5D_io_info_t *io_info, const H5D_type_info_t *type
 static herr_t H5D_chunk_write(H5D_io_info_t *io_info, const H5D_type_info_t *type_info,
     hsize_t nelmts, const H5S_t *file_space, const H5S_t *mem_space,
     H5D_chunk_map_t *fm);
+static herr_t H5D_chunk_flush(H5D_t *dset, hid_t dxpl_id, unsigned flags);
 static herr_t H5D_chunk_io_term(const H5D_chunk_map_t *fm);
 
 /* "Nonexistent" layout operation callback */
@@ -206,7 +207,10 @@ static herr_t H5D_chunk_file_cb(void *elem, hid_t type_id, unsigned ndims,
     const hsize_t *coords, void *fm);
 static herr_t H5D_chunk_mem_cb(void *elem, hid_t type_id, unsigned ndims,
     const hsize_t *coords, void *fm);
-
+static herr_t H5D_chunk_flush_entry(const H5D_t *dset, hid_t dxpl_id,
+    const H5D_dxpl_cache_t *dxpl_cache, H5D_rdcc_ent_t *ent, hbool_t reset);
+static herr_t H5D_chunk_cache_evict(const H5D_t *dset, hid_t dxpl_id,
+    const H5D_dxpl_cache_t *dxpl_cache, H5D_rdcc_ent_t *ent, hbool_t flush);
 
 
 /*********************/
@@ -227,6 +231,7 @@ const H5D_layout_ops_t H5D_LOPS_CHUNK[1] = {{
 #endif /* H5_HAVE_PARALLEL */
     NULL,
     NULL,
+    H5D_chunk_flush,
     H5D_chunk_io_term
 }};
 
@@ -249,6 +254,7 @@ const H5D_layout_ops_t H5D_LOPS_NONEXISTENT[1] = {{
 #endif /* H5_HAVE_PARALLEL */
     H5D_nonexistent_readvv,
     NULL,
+    NULL,
     NULL
 }};
 
@@ -1923,6 +1929,61 @@ done:
 
 
 /*-------------------------------------------------------------------------
+ * Function:	H5D_chunk_flush
+ *
+ * Purpose:	Writes all dirty chunks to disk and optionally preempts them
+ *		from the cache.
+ *
+ * Return:	Non-negative on success/Negative on failure
+ *
+ * Programmer:	Robb Matzke
+ *              Thursday, May 21, 1998
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+H5D_chunk_flush(H5D_t *dset, hid_t dxpl_id, unsigned flags)
+{
+    H5D_dxpl_cache_t _dxpl_cache;       /* Data transfer property cache buffer */
+    H5D_dxpl_cache_t *dxpl_cache = &_dxpl_cache;   /* Data transfer property cache */
+    H5D_rdcc_t *rdcc = &(dset->shared->cache.chunk);
+    unsigned		nerrors = 0;
+    H5D_rdcc_ent_t	*ent, *next;
+    herr_t ret_value = SUCCEED;       /* Return value */
+
+    FUNC_ENTER_NOAPI_NOINIT(H5D_chunk_flush)
+
+    /* Sanity check */
+    HDassert(dset);
+
+    /* Flush any data caught in sieve buffer */
+    if(H5D_flush_sieve_buf(dset, dxpl_id) < 0)
+        HGOTO_ERROR(H5E_DATASET, H5E_CANTFLUSH, FAIL, "unable to flush sieve buffer")
+
+    /* Fill the DXPL cache values for later use */
+    if(H5D_get_dxpl_cache(dxpl_id, &dxpl_cache) < 0)
+        HGOTO_ERROR(H5E_DATASET, H5E_CANTGET, FAIL, "can't fill dxpl cache")
+
+    /* Loop over all entries in the chunk cache */
+    for(ent = rdcc->head; ent; ent = next) {
+	next = ent->next;
+	if((flags & H5F_FLUSH_INVALIDATE)) {
+	    if(H5D_chunk_cache_evict(dset, dxpl_id, dxpl_cache, ent, TRUE) < 0)
+		nerrors++;
+	} else {
+	    if(H5D_chunk_flush_entry(dset, dxpl_id, dxpl_cache, ent, FALSE) < 0)
+		nerrors++;
+	}
+    } /* end for */
+    if(nerrors)
+	HGOTO_ERROR(H5E_IO, H5E_CANTFLUSH, FAIL, "unable to flush one or more raw data chunks")
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5D_chunk_flush() */
+
+
+/*-------------------------------------------------------------------------
  * Function:	H5D_chunk_io_term
  *
  * Purpose:	Destroy I/O operation information.
@@ -2913,54 +2974,6 @@ done:
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5D_chunk_flush
- *
- * Purpose:	Writes all dirty chunks to disk and optionally preempts them
- *		from the cache.
- *
- * Return:	Non-negative on success/Negative on failure
- *
- * Programmer:	Robb Matzke
- *              Thursday, May 21, 1998
- *
- *-------------------------------------------------------------------------
- */
-herr_t
-H5D_chunk_flush(H5D_t *dset, hid_t dxpl_id, unsigned flags)
-{
-    H5D_dxpl_cache_t _dxpl_cache;       /* Data transfer property cache buffer */
-    H5D_dxpl_cache_t *dxpl_cache = &_dxpl_cache;   /* Data transfer property cache */
-    H5D_rdcc_t *rdcc = &(dset->shared->cache.chunk);
-    unsigned		nerrors = 0;
-    H5D_rdcc_ent_t	*ent, *next;
-    herr_t ret_value = SUCCEED;       /* Return value */
-
-    FUNC_ENTER_NOAPI(H5D_chunk_flush, FAIL)
-
-    /* Fill the DXPL cache values for later use */
-    if(H5D_get_dxpl_cache(dxpl_id, &dxpl_cache) < 0)
-        HGOTO_ERROR(H5E_DATASET, H5E_CANTGET, FAIL, "can't fill dxpl cache")
-
-    /* Loop over all entries in the chunk cache */
-    for(ent = rdcc->head; ent; ent = next) {
-	next = ent->next;
-	if((flags & H5F_FLUSH_INVALIDATE)) {
-	    if(H5D_chunk_cache_evict(dset, dxpl_id, dxpl_cache, ent, TRUE) < 0)
-		nerrors++;
-	} else {
-	    if(H5D_chunk_flush_entry(dset, dxpl_id, dxpl_cache, ent, FALSE) < 0)
-		nerrors++;
-	}
-    } /* end for */
-    if(nerrors)
-	HGOTO_ERROR(H5E_IO, H5E_CANTFLUSH, FAIL, "unable to flush one or more raw data chunks")
-
-done:
-    FUNC_LEAVE_NOAPI(ret_value)
-} /* end H5D_chunk_flush() */
-
-
-/*-------------------------------------------------------------------------
  * Function:	H5D_chunk_allocated_cb
  *
  * Purpose:	Simply counts the number of chunks for a dataset.
diff --git a/src/H5Dcompact.c b/src/H5Dcompact.c
index 09abee0..a1f5044 100644
--- a/src/H5Dcompact.c
+++ b/src/H5Dcompact.c
@@ -68,6 +68,7 @@ static ssize_t H5D_compact_readvv(const H5D_io_info_t *io_info,
 static ssize_t H5D_compact_writevv(const H5D_io_info_t *io_info,
     size_t dset_max_nseq, size_t *dset_curr_seq, size_t dset_size_arr[], hsize_t dset_offset_arr[],
     size_t mem_max_nseq, size_t *mem_curr_seq, size_t mem_size_arr[], hsize_t mem_offset_arr[]);
+static herr_t H5D_compact_flush(H5D_t *dset, hid_t dxpl_id, unsigned flags);
 
 
 /*********************/
@@ -88,6 +89,7 @@ const H5D_layout_ops_t H5D_LOPS_COMPACT[1] = {{
 #endif /* H5_HAVE_PARALLEL */
     H5D_compact_readvv,
     H5D_compact_writevv,
+    H5D_compact_flush,
     NULL
 }};
 
@@ -332,6 +334,40 @@ done:
 
 
 /*-------------------------------------------------------------------------
+ * Function:	H5D_compact_flush
+ *
+ * Purpose:	Writes dirty compact data to object header
+ *
+ * Return:	Non-negative on success/Negative on failure
+ *
+ * Programmer:	Quincey Koziol
+ *              Monday, July 27, 2009
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+H5D_compact_flush(H5D_t *dset, hid_t dxpl_id, unsigned UNUSED flags)
+{
+    herr_t ret_value = SUCCEED;       /* Return value */
+
+    FUNC_ENTER_NOAPI_NOINIT(H5D_compact_flush)
+
+    /* Sanity check */
+    HDassert(dset);
+
+    /* Check if the buffered compact information is dirty */
+    if(dset->shared->layout.u.compact.dirty) {
+        if(H5O_msg_write(&(dset->oloc), H5O_LAYOUT_ID, 0, H5O_UPDATE_TIME, &(dset->shared->layout), dxpl_id) < 0)
+            HGOTO_ERROR(H5E_FILE, H5E_CANTINIT, FAIL, "unable to update layout message")
+        dset->shared->layout.u.compact.dirty = FALSE;
+    } /* end if */
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5D_compact_flush() */
+
+
+/*-------------------------------------------------------------------------
  * Function:    H5D_compact_copy
  *
  * Purpose:     Copy compact storage raw data from SRC file to DST file.
diff --git a/src/H5Dcontig.c b/src/H5Dcontig.c
index 887f37a..11ba22c 100644
--- a/src/H5Dcontig.c
+++ b/src/H5Dcontig.c
@@ -66,6 +66,7 @@ static hbool_t H5D_contig_is_space_alloc(const H5O_layout_t *layout);
 static herr_t H5D_contig_io_init(const H5D_io_info_t *io_info, const H5D_type_info_t *type_info,
     hsize_t nelmts, const H5S_t *file_space, const H5S_t *mem_space,
     H5D_chunk_map_t *cm);
+static herr_t H5D_contig_flush(H5D_t *dset, hid_t dxpl_id, unsigned flags);
 
 /* Helper routines */
 static herr_t H5D_contig_write_one(H5D_io_info_t *io_info, hsize_t offset,
@@ -90,6 +91,7 @@ const H5D_layout_ops_t H5D_LOPS_CONTIG[1] = {{
 #endif /* H5_HAVE_PARALLEL */
     H5D_contig_readvv,
     H5D_contig_writevv,
+    H5D_contig_flush,
     NULL
 }};
 
@@ -1173,6 +1175,37 @@ done:
 
 
 /*-------------------------------------------------------------------------
+ * Function:	H5D_contig_flush
+ *
+ * Purpose:	Writes all dirty data to disk.
+ *
+ * Return:	Non-negative on success/Negative on failure
+ *
+ * Programmer:	Quincey Koziol
+ *              Monday, July 27, 2009
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+H5D_contig_flush(H5D_t *dset, hid_t dxpl_id, unsigned UNUSED flags)
+{
+    herr_t ret_value = SUCCEED;       /* Return value */
+
+    FUNC_ENTER_NOAPI_NOINIT(H5D_contig_flush)
+
+    /* Sanity check */
+    HDassert(dset);
+
+    /* Flush any data in sieve buffer */
+    if(H5D_flush_sieve_buf(dset, dxpl_id) < 0)
+        HGOTO_ERROR(H5E_DATASET, H5E_CANTFLUSH, FAIL, "unable to flush sieve buffer")
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5D_contig_flush() */
+
+
+/*-------------------------------------------------------------------------
  * Function:	H5D_contig_copy
  *
  * Purpose:	Copy contiguous storage raw data from SRC file to DST file.
diff --git a/src/H5Defl.c b/src/H5Defl.c
index cb31630..b9a8345 100644
--- a/src/H5Defl.c
+++ b/src/H5Defl.c
@@ -86,6 +86,7 @@ const H5D_layout_ops_t H5D_LOPS_EFL[1] = {{
 #endif /* H5_HAVE_PARALLEL */
     H5D_efl_readvv,
     H5D_efl_writevv,
+    NULL,
     NULL
 }};
 
diff --git a/src/H5Dint.c b/src/H5Dint.c
index d36dc95..93d0e1d 100644
--- a/src/H5Dint.c
+++ b/src/H5Dint.c
@@ -30,7 +30,6 @@
 #include "H5Dpkg.h"		/* Datasets 				*/
 #include "H5Eprivate.h"		/* Error handling		  	*/
 #include "H5FOprivate.h"        /* File objects                         */
-#include "H5HLprivate.h"	/* Local heaps				*/
 #include "H5Iprivate.h"		/* IDs			  		*/
 #include "H5Lprivate.h"		/* Links		  		*/
 #include "H5MMprivate.h"	/* Memory management			*/
@@ -64,7 +63,6 @@ static H5D_shared_t *H5D_new(hid_t dcpl_id, hbool_t creating, hbool_t vl_type);
 static herr_t H5D_init_type(H5F_t *file, const H5D_t *dset, hid_t type_id,
     const H5T_t *type);
 static herr_t H5D_init_space(H5F_t *file, const H5D_t *dset, const H5S_t *space);
-static herr_t H5D_set_io_ops(H5D_t *dataset);
 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);
@@ -692,58 +690,6 @@ done:
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5D_set_io_ops
- *
- * Purpose:	Set the I/O operation function pointers for a dataset
- *
- * Return:	Non-negative on success/Negative on failure
- *
- * Programmer:	Quincey Koziol
- *		Thursday, March 20, 2008
- *
- *-------------------------------------------------------------------------
- */
-static herr_t
-H5D_set_io_ops(H5D_t *dataset)
-{
-    herr_t ret_value = SUCCEED;		/* Return value */
-
-    FUNC_ENTER_NOAPI_NOINIT(H5D_set_io_ops)
-
-    /* check args */
-    HDassert(dataset);
-
-    /* Set the I/O functions for each layout type */
-    switch(dataset->shared->layout.type) {
-        case H5D_CONTIGUOUS:
-            if(dataset->shared->dcpl_cache.efl.nused > 0)
-                dataset->shared->layout.ops = H5D_LOPS_EFL;
-            else
-                dataset->shared->layout.ops = H5D_LOPS_CONTIG;
-            break;
-
-        case H5D_CHUNKED:
-            dataset->shared->layout.ops = H5D_LOPS_CHUNK;
-
-            /* Set the chunk operations */
-            /* (Only "B-tree" indexing type currently supported */
-            dataset->shared->layout.u.chunk.ops = H5D_COPS_BTREE;
-            break;
-
-        case H5D_COMPACT:
-            dataset->shared->layout.ops = H5D_LOPS_COMPACT;
-            break;
-
-        default:
-            HGOTO_ERROR(H5E_DATASET, H5E_UNSUPPORTED, FAIL, "unknown storage method")
-    } /* end switch */ /*lint !e788 All appropriate cases are covered */
-
-done:
-    FUNC_LEAVE_NOAPI(ret_value)
-} /* end H5D_set_io_ops() */
-
-
-/*-------------------------------------------------------------------------
  * Function:	H5D_update_oh_info
  *
  * Purpose:	Create and fill object header for dataset
@@ -876,86 +822,13 @@ H5D_update_oh_info(H5F_t *file, hid_t dxpl_id, H5D_t *dset, hid_t dapl_id)
     if(H5S_append(file, dxpl_id, oh, dset->shared->space) < 0)
         HGOTO_ERROR(H5E_DATASET, H5E_CANTINIT, FAIL, "unable to update dataspace header message")
 
-    /* Update the filters message, if this is a chunked dataset */
-    if(layout->type == H5D_CHUNKED) {
-        H5O_pline_t     *pline;         /* Dataset's I/O pipeline information */
-
-        pline = &dset->shared->dcpl_cache.pline;
-        if(pline->nused > 0 && H5O_msg_append_oh(file, dxpl_id, oh, H5O_PLINE_ID, H5O_MSG_FLAG_CONSTANT, 0, pline) < 0)
-            HGOTO_ERROR(H5E_DATASET, H5E_CANTINIT, FAIL, "unable to update filter header message")
-    } /* end if */
-
-    /* Initialize the layout information for the new dataset */
-    if(dset->shared->layout.ops->init && (dset->shared->layout.ops->init)(file, dxpl_id, dset, dapl_id) < 0)
-        HGOTO_ERROR(H5E_DATASET, H5E_CANTINIT, FAIL, "unable to initialize layout information")
+    /* Update/create the layout (and I/O pipeline & EFL) messages */
+    if(H5D_layout_oh_create(file, dxpl_id, oh, dset, dapl_id) < 0)
+        HGOTO_ERROR(H5E_DATASET, H5E_CANTINIT, FAIL, "unable to update layout/pline/efl header message")
 
     /* Indicate that the layout information was initialized */
     layout_init = TRUE;
 
-    /*
-     * Allocate storage if space allocate time is early; otherwise delay
-     * allocation until later.
-     */
-    if(fill_prop->alloc_time == H5D_ALLOC_TIME_EARLY)
-        if(H5D_alloc_storage(dset, dxpl_id, H5D_ALLOC_CREATE, FALSE) < 0)
-            HGOTO_ERROR(H5E_DATASET, H5E_CANTINIT, FAIL, "unable to initialize storage")
-
-    /* Update external storage message, if it's used */
-    if(dset->shared->dcpl_cache.efl.nused > 0) {
-        H5O_efl_t *efl = &dset->shared->dcpl_cache.efl; /* Dataset's external file list */
-        H5HL_t *heap;                           /* Pointer to local heap for EFL file names */
-        size_t heap_size = H5HL_ALIGN(1);
-        size_t u;
-
-        /* Determine size of heap needed to stored the file names */
-        for(u = 0; u < efl->nused; ++u)
-            heap_size += H5HL_ALIGN(HDstrlen(efl->slot[u].name) + 1);
-
-        /* Create the heap for the EFL file names */
-        if(H5HL_create(file, dxpl_id, heap_size, &efl->heap_addr/*out*/) < 0)
-            HGOTO_ERROR(H5E_DATASET, H5E_CANTINIT, FAIL, "unable to create EFL file name heap")
-
-        /* Pin the heap down in memory */
-        if(NULL == (heap = H5HL_protect(file, dxpl_id, efl->heap_addr, H5AC_WRITE)))
-            HGOTO_ERROR(H5E_DATASET, H5E_CANTPROTECT, FAIL, "unable to protect EFL file name heap")
-
-        /* Insert "empty" name first */
-        if((size_t)(-1) == H5HL_insert(file, dxpl_id, heap, (size_t)1, "")) {
-            H5HL_unprotect(file, dxpl_id, heap, efl->heap_addr);
-            HGOTO_ERROR(H5E_DATASET, H5E_CANTINSERT, FAIL, "unable to insert file name into heap")
-        } /* end if */
-
-        for(u = 0; u < efl->nused; ++u) {
-            size_t offset;      /* Offset of file name in heap */
-
-            /* Insert file name into heap */
-            if((size_t)(-1) == (offset = H5HL_insert(file, dxpl_id, heap,
-                        HDstrlen(efl->slot[u].name) + 1, efl->slot[u].name))) {
-                H5HL_unprotect(file, dxpl_id, heap, efl->heap_addr);
-                HGOTO_ERROR(H5E_DATASET, H5E_CANTINSERT, FAIL, "unable to insert file name into heap")
-            } /* end if */
-
-            /* Store EFL file name offset */
-            HDassert(0 == efl->slot[u].name_offset);
-            efl->slot[u].name_offset = offset;
-        } /* end for */
-
-        /* Release the heap */
-        if(H5HL_unprotect(file, dxpl_id, heap, efl->heap_addr) < 0)
-            HGOTO_ERROR(H5E_DATASET, H5E_CANTUNPROTECT, FAIL, "unable to unprotect EFL file name heap")
-        heap = NULL;
-
-        /* Insert EFL message into dataset object header */
-        if(H5O_msg_append_oh(file, dxpl_id, oh, H5O_EFL_ID, H5O_MSG_FLAG_CONSTANT, 0, efl) < 0)
-            HGOTO_ERROR(H5E_DATASET, H5E_CANTINIT, FAIL, "unable to update external file list message")
-    } /* end if */
-
-    /* Create layout message */
-    /* (Don't make layout message constant unless allocation time is early, since space may not be allocated) */
-    /* (Note: this is relying on H5D_alloc_storage not calling H5O_msg_write during dataset creation) */
-    if(H5O_msg_append_oh(file, dxpl_id, oh, H5O_LAYOUT_ID, ((fill_prop->alloc_time == H5D_ALLOC_TIME_EARLY && H5D_COMPACT != layout->type) ? H5O_MSG_FLAG_CONSTANT : 0), 0, layout) < 0)
-         HGOTO_ERROR(H5E_DATASET, H5E_CANTINIT, FAIL, "unable to update layout")
-
 #ifdef H5O_ENABLE_BOGUS
 {
     H5P_genplist_t     *dc_plist;               /* Dataset's creation property list */
@@ -1150,7 +1023,7 @@ H5D_create(H5F_t *file, hid_t type_id, const H5S_t *space, hid_t dcpl_id,
         new_dset->shared->dcpl_cache.fill.alloc_time = H5D_ALLOC_TIME_EARLY;
 
     /* Set the dataset's I/O operations */
-    if(H5D_set_io_ops(new_dset) < 0)
+    if(H5D_layout_set_io_ops(new_dset) < 0)
         HGOTO_ERROR(H5E_DATASET, H5E_CANTINIT, NULL, "unable to initialize I/O operations")
 
     /* Create the layout information for the new dataset */
@@ -1158,7 +1031,7 @@ H5D_create(H5F_t *file, hid_t type_id, const H5S_t *space, hid_t dcpl_id,
         HGOTO_ERROR(H5E_DATASET, H5E_CANTINIT, NULL, "unable to construct layout information")
 
     /* Update the dataset's object header info. */
-    if(H5D_update_oh_info(file, dxpl_id, new_dset, dapl_id) != SUCCEED)
+    if(H5D_update_oh_info(file, dxpl_id, new_dset, dapl_id) < 0)
         HGOTO_ERROR(H5E_DATASET, H5E_CANTINIT, NULL, "can't update the metadata cache")
 
     /* Indicate that the layout information was initialized */
@@ -1360,105 +1233,9 @@ H5D_open_oid(H5D_t *dataset, hid_t dapl_id, hid_t dxpl_id)
     if(NULL == (plist = (H5P_genplist_t *)H5I_object(dataset->shared->dcpl_id)))
         HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "can't get dataset creation property list")
 
-    /* Get the optional filters message */
-    if((msg_exists = H5O_msg_exists(&(dataset->oloc), H5O_PLINE_ID, dxpl_id)) < 0)
-        HGOTO_ERROR(H5E_DATASET, H5E_CANTGET, FAIL, "can't check if message exists")
-    if(msg_exists) {
-        /* Retrieve the I/O pipeline message */
-        if(NULL == H5O_msg_read(&(dataset->oloc), H5O_PLINE_ID, &dataset->shared->dcpl_cache.pline, dxpl_id))
-            HGOTO_ERROR(H5E_DATASET, H5E_CANTGET, FAIL, "can't retrieve message")
-
-        /* Set the I/O pipeline info in the property list */
-        if(H5P_set(plist, H5D_CRT_DATA_PIPELINE_NAME, &dataset->shared->dcpl_cache.pline) < 0)
-            HGOTO_ERROR(H5E_DATASET, H5E_CANTSET, FAIL, "can't set pipeline")
-    } /* end if */
-
-    /*
-     * Get the raw data layout info.  It's actually stored in two locations:
-     * the storage message of the dataset (dataset->storage) and certain
-     * values are copied to the dataset create plist so the user can query
-     * them.
-     */
-    if(NULL == H5O_msg_read(&(dataset->oloc), H5O_LAYOUT_ID, &(dataset->shared->layout), dxpl_id))
-        HGOTO_ERROR(H5E_DATASET, H5E_CANTINIT, FAIL, "unable to read data layout message")
-
-    /* Check for external file list message (which might not exist) */
-    if((msg_exists = H5O_msg_exists(&(dataset->oloc), H5O_EFL_ID, dxpl_id)) < 0)
-        HGOTO_ERROR(H5E_DATASET, H5E_CANTGET, FAIL, "can't check if message exists")
-    if(msg_exists) {
-        /* Retrieve the EFL  message */
-        if(NULL == H5O_msg_read(&(dataset->oloc), H5O_EFL_ID, &dataset->shared->dcpl_cache.efl, dxpl_id))
-            HGOTO_ERROR(H5E_DATASET, H5E_CANTGET, FAIL, "can't retrieve message")
-
-        /* Set the EFL info in the property list */
-        if(H5P_set(plist, H5D_CRT_EXT_FILE_LIST_NAME, &dataset->shared->dcpl_cache.efl) < 0)
-            HGOTO_ERROR(H5E_DATASET, H5E_CANTSET, FAIL, "can't set external file list")
-
-        /* Set the dataset's I/O operations */
-        dataset->shared->layout.ops = H5D_LOPS_EFL;
-    } /* end if */
-
-    /* Sanity check that the layout operations are set up */
-    HDassert(dataset->shared->layout.ops);
-
-    /* Adjust chunk dimensions to omit datatype size (in last dimension) for creation property */
-    if(H5D_CHUNKED == dataset->shared->layout.type)
-        dataset->shared->layout.u.chunk.ndims--;
-    /* Copy layout to the DCPL */
-    if(H5P_set(plist, H5D_CRT_LAYOUT_NAME, &dataset->shared->layout) < 0)
-        HGOTO_ERROR(H5E_DATASET, H5E_CANTSET, FAIL, "can't set layout")
-    /* Adjust chunk dimensions back again (*sigh*) */
-    if(H5D_CHUNKED == dataset->shared->layout.type)
-        dataset->shared->layout.u.chunk.ndims++;
-
-    switch(dataset->shared->layout.type) {
-        case H5D_CONTIGUOUS:
-            /* 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
-             */
-            if(dataset->shared->layout.version < 3) {
-                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)
-                    HGOTO_ERROR(H5E_DATASET, H5E_CANTGET, FAIL, "unable to retrieve number of elements in dataspace")
-                nelmts = (hsize_t)snelmts;
-
-                /* Get the datatype's size */
-                if(0 == (dt_size = H5T_GET_SIZE(dataset->shared->type)))
-                    HGOTO_ERROR(H5E_DATASET, H5E_CANTGET, FAIL, "unable to retrieve size of datatype")
-
-                /* Compute the size of the dataset's contiguous storage */
-                tmp_size = nelmts * dt_size;
-
-                /* Check for overflow during multiplication */
-                if(nelmts != (tmp_size / dt_size))
-                    HGOTO_ERROR(H5E_DATASET, H5E_OVERFLOW, FAIL, "size of dataset's storage overflowed")
-
-                /* Assign the dataset's contiguous storage size */
-                dataset->shared->layout.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);
-            break;
-
-        case H5D_CHUNKED:
-            /* Initialize the chunk cache for the dataset */
-            if(H5D_chunk_init(dataset->oloc.file, dxpl_id, dataset, dapl_id) < 0)
-                HGOTO_ERROR(H5E_DATASET, H5E_CANTINIT, FAIL, "can't initialize chunk cache")
-            break;
-
-        case H5D_COMPACT:
-            break;
-
-        default:
-            HGOTO_ERROR(H5E_DATASET, H5E_UNSUPPORTED, FAIL, "unknown storage method")
-    } /* end switch */ /*lint !e788 All appropriate cases are covered */
+    /* Get the layout/pline/efl message information */
+    if(H5D_layout_oh_read(dataset, dxpl_id, dapl_id, plist) < 0)
+        HGOTO_ERROR(H5E_DATASET, H5E_CANTGET, FAIL, "can't get layout/pline/efl info")
 
     /* Point at dataset's copy, to cache it for later */
     fill_prop = &dataset->shared->dcpl_cache.fill;
@@ -1849,9 +1626,6 @@ H5D_alloc_storage(H5D_t *dset/*in,out*/, hid_t dxpl_id, H5D_time_alloc_t time_al
                         HDmemset(layout->u.compact.buf, 0, layout->u.compact.size);
                     layout->u.compact.dirty = TRUE;
 
-                    /* Indicate that we set the storage addr */
-                    addr_set = TRUE;
-
                     /* Indicate that we should initialize storage space */
                     must_init_space = TRUE;
                 } /* end if */
@@ -2406,6 +2180,47 @@ done:
 
 
 /*-------------------------------------------------------------------------
+ * Function:    H5D_flush_sieve_buf
+ *
+ * Purpose:     Flush any dataset sieve buffer info cached in memory
+ *
+ * Return:	Success:	Non-negative
+ *		Failure:	Negative
+ *
+ * Programmer:  Quincey Koziol
+ *              July 27, 2009
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5D_flush_sieve_buf(H5D_t *dataset, hid_t dxpl_id)
+{
+    herr_t ret_value = SUCCEED;         /* Return value */
+
+    FUNC_ENTER_NOAPI_NOINIT(H5D_flush_sieve_buf)
+
+    /* Check args */
+    HDassert(dataset);
+
+    /* Flush the raw data buffer, if we have a dirty one */
+    if(dataset->shared->cache.contig.sieve_buf && dataset->shared->cache.contig.sieve_dirty) {
+        HDassert(dataset->shared->layout.type != H5D_COMPACT);      /* We should never have a sieve buffer for compact storage */
+
+        /* Write dirty data sieve buffer to file */
+        if(H5F_block_write(dataset->oloc.file, H5FD_MEM_DRAW, dataset->shared->cache.contig.sieve_loc,
+                dataset->shared->cache.contig.sieve_size, dxpl_id, dataset->shared->cache.contig.sieve_buf) < 0)
+            HGOTO_ERROR(H5E_IO, H5E_WRITEERROR, FAIL, "block write failed")
+
+        /* Reset sieve buffer dirty flag */
+        dataset->shared->cache.contig.sieve_dirty = FALSE;
+    } /* end if */
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5D_flush_sieve_buf() */
+
+
+/*-------------------------------------------------------------------------
  * Function:    H5D_flush_real
  *
  * Purpose:     Flush any dataset information cached in memory
@@ -2439,8 +2254,8 @@ H5D_flush_real(H5D_t *dataset, hid_t dxpl_id, unsigned flags)
 
         /* Update the layout on disk, if it's been changed */
         if(dataset->shared->layout_dirty) {
-            if(H5O_msg_write_oh(dataset->oloc.file, dxpl_id, oh, H5O_LAYOUT_ID, H5O_MSG_FLAG_CONSTANT, update_flags, &dataset->shared->layout) < 0)
-                HGOTO_ERROR(H5E_DATASET, H5E_WRITEERROR, FAIL, "unable to update layout message")
+            if(H5D_layout_oh_write(dataset, dxpl_id, oh, update_flags) < 0)
+                HGOTO_ERROR(H5E_DATASET, H5E_WRITEERROR, FAIL, "unable to update layout/pline/efl info")
             dataset->shared->layout_dirty = FALSE;
 
             /* Reset the "update the modification time" flag, so we only do it once */
@@ -2461,44 +2276,10 @@ H5D_flush_real(H5D_t *dataset, hid_t dxpl_id, unsigned flags)
         HDassert(update_flags == 0);
     } /* end if */
 
-    /* Flush the raw data buffer, if we have a dirty one */
-    if(dataset->shared->cache.contig.sieve_buf && dataset->shared->cache.contig.sieve_dirty) {
-        HDassert(dataset->shared->layout.type != H5D_COMPACT);      /* We should never have a sieve buffer for compact storage */
-
-        /* Write dirty data sieve buffer to file */
-        if(H5F_block_write(dataset->oloc.file, H5FD_MEM_DRAW, dataset->shared->cache.contig.sieve_loc,
-                dataset->shared->cache.contig.sieve_size, dxpl_id, dataset->shared->cache.contig.sieve_buf) < 0)
-            HGOTO_ERROR(H5E_IO, H5E_WRITEERROR, FAIL, "block write failed")
-
-        /* Reset sieve buffer dirty flag */
-        dataset->shared->cache.contig.sieve_dirty = FALSE;
-    } /* end if */
-
-    /* Flush cached information for each kind of dataset */
-    switch(dataset->shared->layout.type) {
-        case H5D_CONTIGUOUS:
-            break;
-
-        case H5D_CHUNKED:
-            /* Flush the raw data cache */
-            if(H5D_chunk_flush(dataset, dxpl_id, flags & H5F_FLUSH_INVALIDATE) < 0)
-                HGOTO_ERROR(H5E_CACHE, H5E_CANTFLUSH, FAIL, "unable to flush raw data cache")
-            break;
-
-        case H5D_COMPACT:
-            if(dataset->shared->layout.u.compact.dirty) {
-                if(H5O_msg_write(&(dataset->oloc), H5O_LAYOUT_ID, 0, H5O_UPDATE_TIME, &(dataset->shared->layout), dxpl_id) < 0)
-                    HGOTO_ERROR(H5E_FILE, H5E_CANTINIT, FAIL, "unable to update layout message")
-                dataset->shared->layout.u.compact.dirty = FALSE;
-            } /* end if */
-            break;
-
-        default:
-            HDassert("not implemented yet" && 0);
-#ifdef NDEBUG
-            HGOTO_ERROR(H5E_IO, H5E_UNSUPPORTED, FAIL, "unsupported storage layout")
-#endif /* NDEBUG */
-    } /* end switch */ /*lint !e788 All appropriate cases are covered */
+    /* Flush cached raw data for each kind of dataset layout */
+    if(dataset->shared->layout.ops->flush && 
+            (dataset->shared->layout.ops->flush)(dataset, dxpl_id, flags) < 0)
+        HGOTO_ERROR(H5E_DATASET, H5E_CANTFLUSH, FAIL, "unable to flush raw data")
 
 done:
     /* Release pointer to object header */
diff --git a/src/H5Dlayout.c b/src/H5Dlayout.c
new file mode 100644
index 0000000..4966cb5
--- /dev/null
+++ b/src/H5Dlayout.c
@@ -0,0 +1,403 @@
+/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
+ * Copyright by The HDF Group.                                               *
+ * Copyright by the Board of Trustees of the University of Illinois.         *
+ * All rights reserved.                                                      *
+ *                                                                           *
+ * This file is part of HDF5.  The full HDF5 copyright notice, including     *
+ * terms governing use, modification, and redistribution, is contained in    *
+ * the files COPYING and Copyright.html.  COPYING can be found at the root   *
+ * of the source code distribution tree; Copyright.html can be found at the  *
+ * root level of an installed copy of the electronic HDF5 document set and   *
+ * is linked from the top-level documents page.  It can also be found at     *
+ * http://hdfgroup.org/HDF5/doc/Copyright.html.  If you do not have          *
+ * access to either file, you may request a copy from help@hdfgroup.org.     *
+ * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
+
+/****************/
+/* Module Setup */
+/****************/
+
+#define H5D_PACKAGE		/*suppress error about including H5Dpkg	  */
+
+
+/***********/
+/* Headers */
+/***********/
+#include "H5private.h"		/* Generic Functions			*/
+#include "H5Dpkg.h"		/* Datasets 				*/
+#include "H5Eprivate.h"		/* Error handling		  	*/
+#include "H5HLprivate.h"	/* Local heaps				*/
+
+
+/****************/
+/* Local Macros */
+/****************/
+
+
+/******************/
+/* Local Typedefs */
+/******************/
+
+
+/********************/
+/* Local Prototypes */
+/********************/
+
+
+/*********************/
+/* Package Variables */
+/*********************/
+
+
+/*****************************/
+/* Library Private Variables */
+/*****************************/
+
+
+/*******************/
+/* Local Variables */
+/*******************/
+
+
+
+/*-------------------------------------------------------------------------
+ * Function:	H5D_layout_set_io_ops
+ *
+ * Purpose:	Set the I/O operation function pointers for a dataset,
+ *              according to the dataset's layout
+ *
+ * Return:	Non-negative on success/Negative on failure
+ *
+ * Programmer:	Quincey Koziol
+ *		Thursday, March 20, 2008
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5D_layout_set_io_ops(const H5D_t *dataset)
+{
+    herr_t ret_value = SUCCEED;		/* Return value */
+
+    FUNC_ENTER_NOAPI(H5D_layout_set_io_ops, FAIL)
+
+    /* check args */
+    HDassert(dataset);
+
+    /* Set the I/O functions for each layout type */
+    switch(dataset->shared->layout.type) {
+        case H5D_CONTIGUOUS:
+            if(dataset->shared->dcpl_cache.efl.nused > 0)
+                dataset->shared->layout.ops = H5D_LOPS_EFL;
+            else
+                dataset->shared->layout.ops = H5D_LOPS_CONTIG;
+            break;
+
+        case H5D_CHUNKED:
+            dataset->shared->layout.ops = H5D_LOPS_CHUNK;
+
+            /* Set the chunk operations */
+            /* (Only "B-tree" indexing type currently supported */
+            dataset->shared->layout.u.chunk.ops = H5D_COPS_BTREE;
+            break;
+
+        case H5D_COMPACT:
+            dataset->shared->layout.ops = H5D_LOPS_COMPACT;
+            break;
+
+        default:
+            HGOTO_ERROR(H5E_DATASET, H5E_UNSUPPORTED, FAIL, "unknown storage method")
+    } /* end switch */ /*lint !e788 All appropriate cases are covered */
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5D_layout_set_io_ops() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:	H5D_layout_oh_create
+ *
+ * Purpose:	Create layout/pline/efl information for dataset
+ *
+ * Return:	Success:    SUCCEED
+ *		Failure:    FAIL
+ *
+ * Programmer:	Quincey Koziol
+ *		Monday, July 27, 2009
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5D_layout_oh_create(H5F_t *file, hid_t dxpl_id, H5O_t *oh, H5D_t *dset,
+    hid_t dapl_id)
+{
+    H5O_layout_t        *layout;         /* Dataset's layout information */
+    const H5O_fill_t	*fill_prop;     /* Pointer to dataset's fill value information */
+    hbool_t             layout_init = FALSE;    /* Flag to indicate that chunk information was initialized */
+    herr_t ret_value = SUCCEED;         /* Return value */
+
+    FUNC_ENTER_NOAPI_NOINIT(H5D_layout_oh_create)
+
+    /* Sanity checking */
+    HDassert(file);
+    HDassert(oh);
+    HDassert(dset);
+
+    /* Set some local variables, for convenience */
+    layout = &dset->shared->layout;
+    fill_prop = &dset->shared->dcpl_cache.fill;
+
+    /* Update the filters message, if this is a chunked dataset */
+    if(layout->type == H5D_CHUNKED) {
+        H5O_pline_t     *pline;         /* Dataset's I/O pipeline information */
+
+        pline = &dset->shared->dcpl_cache.pline;
+        if(pline->nused > 0 && H5O_msg_append_oh(file, dxpl_id, oh, H5O_PLINE_ID, H5O_MSG_FLAG_CONSTANT, 0, pline) < 0)
+            HGOTO_ERROR(H5E_DATASET, H5E_CANTINIT, FAIL, "unable to update filter header message")
+    } /* end if */
+
+    /* Initialize the layout information for the new dataset */
+    if(dset->shared->layout.ops->init && (dset->shared->layout.ops->init)(file, dxpl_id, dset, dapl_id) < 0)
+        HGOTO_ERROR(H5E_DATASET, H5E_CANTINIT, FAIL, "unable to initialize layout information")
+
+    /* Indicate that the layout information was initialized */
+    layout_init = TRUE;
+
+    /*
+     * Allocate storage if space allocate time is early; otherwise delay
+     * allocation until later.
+     */
+    if(fill_prop->alloc_time == H5D_ALLOC_TIME_EARLY)
+        if(H5D_alloc_storage(dset, dxpl_id, H5D_ALLOC_CREATE, FALSE) < 0)
+            HGOTO_ERROR(H5E_DATASET, H5E_CANTINIT, FAIL, "unable to initialize storage")
+
+    /* Update external storage message, if it's used */
+    if(dset->shared->dcpl_cache.efl.nused > 0) {
+        H5O_efl_t *efl = &dset->shared->dcpl_cache.efl; /* Dataset's external file list */
+        H5HL_t *heap;                           /* Pointer to local heap for EFL file names */
+        size_t heap_size = H5HL_ALIGN(1);
+        size_t u;
+
+        /* Determine size of heap needed to stored the file names */
+        for(u = 0; u < efl->nused; ++u)
+            heap_size += H5HL_ALIGN(HDstrlen(efl->slot[u].name) + 1);
+
+        /* Create the heap for the EFL file names */
+        if(H5HL_create(file, dxpl_id, heap_size, &efl->heap_addr/*out*/) < 0)
+            HGOTO_ERROR(H5E_DATASET, H5E_CANTINIT, FAIL, "unable to create EFL file name heap")
+
+        /* Pin the heap down in memory */
+        if(NULL == (heap = H5HL_protect(file, dxpl_id, efl->heap_addr, H5AC_WRITE)))
+            HGOTO_ERROR(H5E_DATASET, H5E_CANTPROTECT, FAIL, "unable to protect EFL file name heap")
+
+        /* Insert "empty" name first */
+        if((size_t)(-1) == H5HL_insert(file, dxpl_id, heap, (size_t)1, "")) {
+            H5HL_unprotect(file, dxpl_id, heap, efl->heap_addr);
+            HGOTO_ERROR(H5E_DATASET, H5E_CANTINSERT, FAIL, "unable to insert file name into heap")
+        } /* end if */
+
+        for(u = 0; u < efl->nused; ++u) {
+            size_t offset;      /* Offset of file name in heap */
+
+            /* Insert file name into heap */
+            if((size_t)(-1) == (offset = H5HL_insert(file, dxpl_id, heap,
+                        HDstrlen(efl->slot[u].name) + 1, efl->slot[u].name))) {
+                H5HL_unprotect(file, dxpl_id, heap, efl->heap_addr);
+                HGOTO_ERROR(H5E_DATASET, H5E_CANTINSERT, FAIL, "unable to insert file name into heap")
+            } /* end if */
+
+            /* Store EFL file name offset */
+            HDassert(0 == efl->slot[u].name_offset);
+            efl->slot[u].name_offset = offset;
+        } /* end for */
+
+        /* Release the heap */
+        if(H5HL_unprotect(file, dxpl_id, heap, efl->heap_addr) < 0)
+            HGOTO_ERROR(H5E_DATASET, H5E_CANTUNPROTECT, FAIL, "unable to unprotect EFL file name heap")
+        heap = NULL;
+
+        /* Insert EFL message into dataset object header */
+        if(H5O_msg_append_oh(file, dxpl_id, oh, H5O_EFL_ID, H5O_MSG_FLAG_CONSTANT, 0, efl) < 0)
+            HGOTO_ERROR(H5E_DATASET, H5E_CANTINIT, FAIL, "unable to update external file list message")
+    } /* end if */
+
+    /* Create layout message */
+    /* (Don't make layout message constant unless allocation time is early, since space may not be allocated) */
+    /* (Note: this is relying on H5D_alloc_storage not calling H5O_msg_write during dataset creation) */
+    if(H5O_msg_append_oh(file, dxpl_id, oh, H5O_LAYOUT_ID, ((fill_prop->alloc_time == H5D_ALLOC_TIME_EARLY && H5D_COMPACT != layout->type) ? H5O_MSG_FLAG_CONSTANT : 0), 0, layout) < 0)
+         HGOTO_ERROR(H5E_DATASET, H5E_CANTINIT, FAIL, "unable to update layout")
+
+done:
+    /* Error cleanup */
+    if(ret_value < 0) {
+        if(dset->shared->layout.type == H5D_CHUNKED && layout_init) {
+            if(H5D_chunk_dest(file, dxpl_id, dset) < 0)
+                HDONE_ERROR(H5E_DATASET, H5E_CANTRELEASE, FAIL, "unable to destroy chunk cache")
+        } /* end if */
+    } /* end if */
+
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5D_layout_oh_create() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:	H5D_layout_oh_read
+ *
+ * Purpose:	Read layout/pline/efl information for dataset
+ *
+ * Return:	Success:    SUCCEED
+ *		Failure:    FAIL
+ *
+ * Programmer:	Quincey Koziol
+ *		Monday, July 27, 2009
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5D_layout_oh_read(H5D_t *dataset, hid_t dxpl_id, hid_t dapl_id, H5P_genplist_t *plist)
+{
+    htri_t msg_exists;                  /* Whether a particular type of message exists */
+    herr_t ret_value = SUCCEED;         /* Return value */
+
+    FUNC_ENTER_NOAPI_NOINIT(H5D_layout_oh_read)
+
+    /* Sanity checking */
+    HDassert(dataset);
+    HDassert(plist);
+
+    /* Get the optional filters message */
+    if((msg_exists = H5O_msg_exists(&(dataset->oloc), H5O_PLINE_ID, dxpl_id)) < 0)
+        HGOTO_ERROR(H5E_DATASET, H5E_CANTGET, FAIL, "can't check if message exists")
+    if(msg_exists) {
+        /* Retrieve the I/O pipeline message */
+        if(NULL == H5O_msg_read(&(dataset->oloc), H5O_PLINE_ID, &dataset->shared->dcpl_cache.pline, dxpl_id))
+            HGOTO_ERROR(H5E_DATASET, H5E_CANTGET, FAIL, "can't retrieve message")
+
+        /* Set the I/O pipeline info in the property list */
+        if(H5P_set(plist, H5D_CRT_DATA_PIPELINE_NAME, &dataset->shared->dcpl_cache.pline) < 0)
+            HGOTO_ERROR(H5E_DATASET, H5E_CANTSET, FAIL, "can't set pipeline")
+    } /* end if */
+
+    /*
+     * Get the raw data layout info.  It's actually stored in two locations:
+     * the storage message of the dataset (dataset->storage) and certain
+     * values are copied to the dataset create plist so the user can query
+     * them.
+     */
+    if(NULL == H5O_msg_read(&(dataset->oloc), H5O_LAYOUT_ID, &(dataset->shared->layout), dxpl_id))
+        HGOTO_ERROR(H5E_DATASET, H5E_CANTINIT, FAIL, "unable to read data layout message")
+
+    /* Check for external file list message (which might not exist) */
+    if((msg_exists = H5O_msg_exists(&(dataset->oloc), H5O_EFL_ID, dxpl_id)) < 0)
+        HGOTO_ERROR(H5E_DATASET, H5E_CANTGET, FAIL, "can't check if message exists")
+    if(msg_exists) {
+        /* Retrieve the EFL  message */
+        if(NULL == H5O_msg_read(&(dataset->oloc), H5O_EFL_ID, &dataset->shared->dcpl_cache.efl, dxpl_id))
+            HGOTO_ERROR(H5E_DATASET, H5E_CANTGET, FAIL, "can't retrieve message")
+
+        /* Set the EFL info in the property list */
+        if(H5P_set(plist, H5D_CRT_EXT_FILE_LIST_NAME, &dataset->shared->dcpl_cache.efl) < 0)
+            HGOTO_ERROR(H5E_DATASET, H5E_CANTSET, FAIL, "can't set external file list")
+
+        /* Set the dataset's I/O operations */
+        dataset->shared->layout.ops = H5D_LOPS_EFL;
+    } /* end if */
+
+    /* Sanity check that the layout operations are set up */
+    HDassert(dataset->shared->layout.ops);
+
+    /* Adjust chunk dimensions to omit datatype size (in last dimension) for creation property */
+    if(H5D_CHUNKED == dataset->shared->layout.type)
+        dataset->shared->layout.u.chunk.ndims--;
+    /* Copy layout to the DCPL */
+    if(H5P_set(plist, H5D_CRT_LAYOUT_NAME, &dataset->shared->layout) < 0)
+        HGOTO_ERROR(H5E_DATASET, H5E_CANTSET, FAIL, "can't set layout")
+    /* Adjust chunk dimensions back again (*sigh*) */
+    if(H5D_CHUNKED == dataset->shared->layout.type)
+        dataset->shared->layout.u.chunk.ndims++;
+
+    switch(dataset->shared->layout.type) {
+        case H5D_CONTIGUOUS:
+            /* 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
+             */
+            if(dataset->shared->layout.version < 3) {
+                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)
+                    HGOTO_ERROR(H5E_DATASET, H5E_CANTGET, FAIL, "unable to retrieve number of elements in dataspace")
+                nelmts = (hsize_t)snelmts;
+
+                /* Get the datatype's size */
+                if(0 == (dt_size = H5T_GET_SIZE(dataset->shared->type)))
+                    HGOTO_ERROR(H5E_DATASET, H5E_CANTGET, FAIL, "unable to retrieve size of datatype")
+
+                /* Compute the size of the dataset's contiguous storage */
+                tmp_size = nelmts * dt_size;
+
+                /* Check for overflow during multiplication */
+                if(nelmts != (tmp_size / dt_size))
+                    HGOTO_ERROR(H5E_DATASET, H5E_OVERFLOW, FAIL, "size of dataset's storage overflowed")
+
+                /* Assign the dataset's contiguous storage size */
+                dataset->shared->layout.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);
+            break;
+
+        case H5D_CHUNKED:
+            /* Initialize the chunk cache for the dataset */
+            if(H5D_chunk_init(dataset->oloc.file, dxpl_id, dataset, dapl_id) < 0)
+                HGOTO_ERROR(H5E_DATASET, H5E_CANTINIT, FAIL, "can't initialize chunk cache")
+            break;
+
+        case H5D_COMPACT:
+            break;
+
+        default:
+            HGOTO_ERROR(H5E_DATASET, H5E_UNSUPPORTED, FAIL, "unknown storage method")
+    } /* end switch */ /*lint !e788 All appropriate cases are covered */
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5D_layout_oh_read() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:	H5D_layout_oh_write
+ *
+ * Purpose:	Read layout/pline/efl information for dataset
+ *
+ * Return:	Success:    SUCCEED
+ *		Failure:    FAIL
+ *
+ * Programmer:	Quincey Koziol
+ *		Monday, July 27, 2009
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5D_layout_oh_write(H5D_t *dataset, hid_t dxpl_id, H5O_t *oh, unsigned update_flags)
+{
+    herr_t ret_value = SUCCEED;         /* Return value */
+
+    FUNC_ENTER_NOAPI_NOINIT(H5D_layout_oh_write)
+
+    /* Sanity checking */
+    HDassert(dataset);
+    HDassert(oh);
+
+    /* Write the layout message to the dataset's header */
+    if(H5O_msg_write_oh(dataset->oloc.file, dxpl_id, oh, H5O_LAYOUT_ID, H5O_MSG_FLAG_CONSTANT, update_flags, &dataset->shared->layout) < 0)
+        HGOTO_ERROR(H5E_DATASET, H5E_WRITEERROR, FAIL, "unable to update layout message")
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5D_layout_oh_write() */
+
diff --git a/src/H5Dpkg.h b/src/H5Dpkg.h
index 43b7e15..3167f56 100644
--- a/src/H5Dpkg.h
+++ b/src/H5Dpkg.h
@@ -118,6 +118,8 @@ typedef ssize_t (*H5D_layout_readvv_func_t)(const struct H5D_io_info_t *io_info,
 typedef ssize_t (*H5D_layout_writevv_func_t)(const struct H5D_io_info_t *io_info,
     size_t dset_max_nseq, size_t *dset_curr_seq, size_t dset_len_arr[], hsize_t dset_offset_arr[],
     size_t mem_max_nseq, size_t *mem_curr_seq, size_t mem_len_arr[], hsize_t mem_offset_arr[]);
+typedef herr_t (*H5D_layout_flush_func_t)(H5D_t *dataset, hid_t dxpl_id,
+    unsigned flags);
 typedef herr_t (*H5D_layout_io_term_func_t)(const struct H5D_chunk_map_t *cm);
 
 /* Typedef for grouping layout I/O routines */
@@ -134,6 +136,7 @@ typedef struct H5D_layout_ops_t {
 #endif /* H5_HAVE_PARALLEL */
     H5D_layout_readvv_func_t readvv;    /* Low-level I/O routine for reading data */
     H5D_layout_writevv_func_t writevv;  /* Low-level I/O routine for writing data */
+    H5D_layout_flush_func_t flush;      /* Low-level I/O routine for flushing raw data */
     H5D_layout_io_term_func_t io_term;  /* I/O shutdown routine */
 } H5D_layout_ops_t;
 
@@ -533,6 +536,7 @@ H5_DLL herr_t H5D_vlen_get_buf_size(void *elem, hid_t type_id, unsigned ndim,
 H5_DLL herr_t H5D_check_filters(H5D_t *dataset);
 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);
 
 /* Functions that perform direct serial I/O operations */
 H5_DLL herr_t H5D_select_read(const H5D_io_info_t *io_info,
@@ -553,6 +557,15 @@ H5_DLL herr_t H5D_scatgath_write(const H5D_io_info_t *io_info,
     const H5D_type_info_t *type_info,
     hsize_t nelmts, const H5S_t *file_space, const H5S_t *mem_space);
 
+/* Functions that operate on dataset's layout information */
+H5_DLL herr_t H5D_layout_set_io_ops(const H5D_t *dataset);
+H5_DLL herr_t H5D_layout_oh_create(H5F_t *file, hid_t dxpl_id, H5O_t *oh,
+    H5D_t *dset, hid_t dapl_id);
+H5_DLL herr_t H5D_layout_oh_read(H5D_t *dset, hid_t dxpl_id, hid_t dapl_id,
+    H5P_genplist_t *plist);
+H5_DLL herr_t H5D_layout_oh_write(H5D_t *dataset, hid_t dxpl_id, H5O_t *oh,
+    unsigned update_flags);
+
 /* Functions that operate on contiguous storage */
 H5_DLL herr_t H5D_contig_alloc(H5F_t *f, hid_t dxpl_id, H5O_layout_t *layout);
 H5_DLL herr_t H5D_contig_fill(H5D_t *dset, hid_t dxpl_id);
@@ -588,7 +601,6 @@ H5_DLL void *H5D_chunk_lock(const H5D_io_info_t *io_info,
 H5_DLL herr_t H5D_chunk_unlock(const H5D_io_info_t *io_info,
     const H5D_chunk_ud_t *udata, hbool_t dirty, unsigned idx_hint, void *chunk,
     uint32_t naccessed);
-H5_DLL herr_t H5D_chunk_flush(H5D_t *dset, hid_t dxpl_id, unsigned flags);
 H5_DLL herr_t H5D_chunk_allocated(H5D_t *dset, hid_t dxpl_id, hsize_t *nbytes);
 H5_DLL herr_t H5D_chunk_allocate(H5D_t *dset, hid_t dxpl_id, hbool_t full_overwrite);
 H5_DLL herr_t H5D_chunk_prune_by_extent(H5D_t *dset, hid_t dxpl_id,
diff --git a/src/Makefile.am b/src/Makefile.am
index f784662..eb264f2 100755
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -48,7 +48,7 @@ libhdf5_la_SOURCES= H5.c H5checksum.c H5dbg.c H5system.c H5timer.c H5trace.c \
         H5C.c H5CS.c \
         H5D.c H5Dbtree.c H5Dchunk.c H5Dcompact.c H5Dcontig.c H5Ddbg.c \
         H5Ddeprec.c H5Defl.c H5Dfill.c H5Dint.c \
-        H5Dio.c \
+        H5Dio.c H5Dlayout.c \
         H5Dmpio.c H5Doh.c H5Dscatgath.c H5Dselect.c H5Dtest.c \
         H5E.c H5Edeprec.c H5Eint.c \
         H5EA.c H5EAcache.c H5EAdbg.c H5EAdblkpage.c H5EAdblock.c H5EAhdr.c \
diff --git a/src/Makefile.in b/src/Makefile.in
index 7b62dab..0e196e6 100644
--- a/src/Makefile.in
+++ b/src/Makefile.in
@@ -84,7 +84,7 @@ am_libhdf5_la_OBJECTS = H5.lo H5checksum.lo H5dbg.lo H5system.lo \
 	H5Bdbg.lo H5B2.lo H5B2cache.lo H5B2dbg.lo H5B2int.lo \
 	H5B2stat.lo H5B2test.lo H5C.lo H5CS.lo H5D.lo H5Dbtree.lo \
 	H5Dchunk.lo H5Dcompact.lo H5Dcontig.lo H5Ddbg.lo H5Ddeprec.lo \
-	H5Defl.lo H5Dfill.lo H5Dint.lo H5Dio.lo H5Dmpio.lo H5Doh.lo \
+	H5Defl.lo H5Dfill.lo H5Dint.lo H5Dio.lo H5Dlayout.lo H5Dmpio.lo H5Doh.lo \
 	H5Dscatgath.lo H5Dselect.lo H5Dtest.lo H5E.lo H5Edeprec.lo \
 	H5Eint.lo H5EA.lo H5EAcache.lo H5EAdbg.lo H5EAdblkpage.lo \
 	H5EAdblock.lo H5EAhdr.lo H5EAiblock.lo H5EAint.lo \
@@ -434,7 +434,7 @@ libhdf5_la_SOURCES = H5.c H5checksum.c H5dbg.c H5system.c H5timer.c H5trace.c \
         H5C.c H5CS.c \
         H5D.c H5Dbtree.c H5Dchunk.c H5Dcompact.c H5Dcontig.c H5Ddbg.c \
         H5Ddeprec.c H5Defl.c H5Dfill.c H5Dint.c \
-        H5Dio.c \
+        H5Dio.c H5Dlayout.c \
         H5Dmpio.c H5Doh.c H5Dscatgath.c H5Dselect.c H5Dtest.c \
         H5E.c H5Edeprec.c H5Eint.c \
         H5EA.c H5EAcache.c H5EAdbg.c H5EAdblkpage.c H5EAdblock.c H5EAhdr.c \
@@ -650,6 +650,7 @@ distclean-compile:
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/H5Dfill.Plo@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/H5Dint.Plo@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/H5Dio.Plo@am__quote@
+@AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/H5Dlayout.Plo@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/H5Dmpio.Plo@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/H5Doh.Plo@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/H5Dscatgath.Plo@am__quote@