[svn-r5814] Purpose:

    Bug Fix

Description:
    It was possible to create corrupted metadata information (either in memory
    or in the file or both) with a parallel I/O program because of the way
    metadata writes were being handled for writes out of the metadata cache.

Solution:
    Added a dataset transfer property called "block before metadata write"
    which is used by the MPI-I/O and MPI-posix drivers to sync up all the
    processes before attempting a metadata write.  This property is currently
    only for metadata writes from the metadata cache.

Platforms tested:
    IRIX64 6.5 (modi4) w/parallel

12 files changed, 310 insertions, 112 deletions

diff --git a/release_docs/RELEASE.txt b/release_docs/RELEASE.txt
index 78b03b1..795a0bb 100644
--- a/release_docs/RELEASE.txt
+++ b/release_docs/RELEASE.txt
@@ -35,21 +35,23 @@ Bug Fixes since HDF5-1.4.0
 
 Library
 -------
+    * Fixed metadata corruption problem which could occur when many objects
+      are created in a file during parallel I/O.  QAK - 2002/07/19
     * Fixed VL memory leak when data is overwritten.  The heap objects holding
       old data are freed.  If the fill value writting time is set to 
       H5D_FILL_TIME_NEVER, the library prohibits user to create VL type dataset.
       The library free all the heap objects storing VL type if there is nested 
-      VL type(a VL type contains another VL type).  SLU 2002/07/10 
+      VL type(a VL type contains another VL type).  SLU - 2002/07/10 
     * Fixed bug in parallel I/O routines where a collective I/O which used
       MPI derived types, followed by an independent I/O would cause the library
-      to hang.  QAK 2002/06/24
+      to hang.  QAK - 2002/06/24
     * Fixed bug in chunking routines where they were using internal allocation
       free routines, instead of malloc/free, preventing user filters from
       working correctly.  Chunks are now allocated/freed with malloc/free and
-      so should the chunks in user filters.  QAK 2002/06/18
+      so should the chunks in user filters.  QAK - 2002/06/18
     * Fixed bug where regular hyperslab selection could get incorrectly
       transferred when the number of elements in a row did not fit evenly
-      into the buffer provided.  QAK 2002/06/12
+      into the buffer provided.  QAK - 2002/06/12
     * Fixed bug (#499) which allowed an "empty" compound or enumerated datatype
       (one with no members) to be used to create a dataset or committed to a
       file.  QAK - 2002/06/11
diff --git a/src/H5.c b/src/H5.c
index 4f53f60..529c4ba 100644
--- a/src/H5.c
+++ b/src/H5.c
@@ -201,6 +201,7 @@ H5_term_library(void)
 	pending += DOWN(TN);
 	pending += DOWN(T);
 	pending += DOWN(A);
+	pending += DOWN(AC);
 	pending += DOWN(P);
 	pending += DOWN(I);
     } while (pending && ntries++ < 100);
diff --git a/src/H5AC.c b/src/H5AC.c
index e49c7bd..80bf603 100644
--- a/src/H5AC.c
+++ b/src/H5AC.c
@@ -31,7 +31,9 @@
 #include "H5Eprivate.h"
 #include "H5Fpkg.h"
 #include "H5FLprivate.h"	/*Free Lists	  */
+#include "H5Iprivate.h"         /* IDs */
 #include "H5MMprivate.h"
+#include "H5Pprivate.h"         /* Property lists */
 
 /*
  * Sorting the cache by address before flushing is sometimes faster
@@ -43,8 +45,16 @@
  * Private file-scope variables.
  */
 #define PABLO_MASK      H5AC_mask
-#define INTERFACE_INIT  NULL
+
+/* Interface initialization */
 static int             interface_initialize_g = 0;
+#define INTERFACE_INIT H5AC_init_interface
+static herr_t H5AC_init_interface(void);
+
+#ifdef H5_HAVE_PARALLEL
+/* Dataset transfer property list for flush calls */
+static hid_t H5AC_dxpl_id=(-1);
+#endif /* H5_HAVE_PARALLEL */
 
 #ifdef H5AC_SORT_BY_ADDR
 static H5AC_t          *current_cache_g = NULL;         /*for sorting */
@@ -66,6 +76,107 @@ H5FL_ARR_DEFINE_STATIC(H5AC_prot_t,-1);
 
 
 /*-------------------------------------------------------------------------
+ * Function:	H5AC_init_interface
+ *
+ * Purpose:	Initialize interface-specific information
+ *
+ * Return:	Non-negative on success/Negative on failure
+ *
+ * Programmer:	Quincey Koziol
+ *              Thursday, July 18, 2002
+ *
+ * Modifications:
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+H5AC_init_interface(void)
+{
+#ifdef H5_HAVE_PARALLEL
+    H5P_genclass_t  *xfer_pclass;   /* Dataset transfer property list class object */
+    H5P_genplist_t  *xfer_plist;    /* Dataset transfer property list object */
+    unsigned block_before_meta_write=1; /* Custom value for "block before meta write" property */
+#endif /* H5_HAVE_PARALLEL */
+
+    FUNC_ENTER_NOINIT(H5AC_init_interface);
+
+#ifdef H5_HAVE_PARALLEL
+    /* Sanity check */
+    assert(H5P_CLS_DATASET_XFER_g!=(-1));
+
+    /* Get the dataset transfer property list class object */
+    if (H5I_GENPROP_CLS != H5I_get_type(H5P_CLS_DATASET_XFER_g) || NULL == (xfer_pclass = H5I_object(H5P_CLS_DATASET_XFER_g)))
+        HRETURN_ERROR(H5E_CACHE, H5E_BADATOM, FAIL, "can't get property list class");
+
+    /* Create a new dataset transfer property list */
+    if ((H5AC_dxpl_id=H5P_create_id(xfer_pclass)) < 0)
+        HRETURN_ERROR(H5E_CACHE, H5E_CANTCREATE, FAIL, "unable to register property list");
+
+    /* Get the property list object */
+    if (NULL == (xfer_plist = H5I_object(H5AC_dxpl_id)))
+        HRETURN_ERROR(H5E_CACHE, H5E_BADATOM, FAIL, "can't get new property list object");
+
+    /* Insert 'block before metadata write' property */
+    if(H5P_insert(xfer_plist,H5AC_BLOCK_BEFORE_META_WRITE_NAME,H5AC_BLOCK_BEFORE_META_WRITE_SIZE,&block_before_meta_write,NULL,NULL,NULL,NULL,NULL)<0)
+        HRETURN_ERROR(H5E_PLIST, H5E_CANTSET, FAIL, "can't insert metadata cache dxpl property");
+#endif /* H5_HAVE_PARALLEL */
+
+    FUNC_LEAVE(SUCCEED);
+} /* end H5AC_init_interface() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:	H5AC_term_interface
+ *
+ * Purpose:	Terminate this interface.
+ *
+ * Return:	Success:	Positive if anything was done that might
+ *				affect other interfaces; zero otherwise.
+ *
+ * 		Failure:	Negative.
+ *
+ * Programmer:	Quincey Koziol
+ *              Thursday, July 18, 2002
+ *
+ * Modifications:
+ *
+ *-------------------------------------------------------------------------
+ */
+int
+H5AC_term_interface(void)
+{
+    int		n=0;
+
+    FUNC_ENTER_NOINIT(H5AC_term_interface);
+
+    if (interface_initialize_g) {
+#ifdef H5_HAVE_PARALLEL
+        if(H5AC_dxpl_id>0) {
+            /* Indicate more work to do */
+            n = 1; /* H5I */
+
+            /* Close H5AC dxpl */
+            if (H5Pclose(H5AC_dxpl_id) < 0)
+                H5E_clear(); /*ignore the error*/
+            else {
+                /* Reset static ID */
+                H5AC_dxpl_id=(-1);
+
+                /* Reset interface initialization flag */
+                interface_initialize_g = 0;
+            } /* end else */
+        } /* end if */
+        else
+#endif /* H5_HAVE_PARALLEL */
+            /* Reset interface initialization flag */
+            interface_initialize_g = 0;
+    } /* end if */
+
+    FUNC_LEAVE(n);
+} /* end H5AC_term_interface() */
+
+
+/*-------------------------------------------------------------------------
  * Function:    H5AC_create
  *
  * Purpose:     Initialize the cache just after a file is opened.  The
@@ -273,7 +384,7 @@ H5AC_find_f(H5F_t *f, const H5AC_class_t *type, haddr_t addr,
      * Load a new thing.  If it can't be loaded, then return an error
      * without preempting anything.
      */
-    if (NULL == (thing = (type->load)(f, addr, udata1, udata2))) {
+    if (NULL == (thing = (type->load)(f, H5P_DATASET_XFER_DEFAULT, addr, udata1, udata2))) {
         HRETURN_ERROR(H5E_CACHE, H5E_CANTLOAD, NULL, "unable to load object");
     }
     /*
@@ -283,13 +394,13 @@ H5AC_find_f(H5F_t *f, const H5AC_class_t *type, haddr_t addr,
         H5AC_subid_t type_id=(*info)->type->id;  /* Remember this for later */
 
         flush = (*info)->type->flush;
-        status = (flush)(f, TRUE, (*info)->addr, (*info));
+        status = (flush)(f, H5AC_dxpl_id, TRUE, (*info)->addr, (*info));
         if (status < 0) {
             /*
              * The old thing could not be removed from the stack.
              * Release the new thing and fail.
              */
-            if ((type->flush)(f, TRUE, addr, thing) < 0) {
+            if ((type->flush)(f, H5AC_dxpl_id, TRUE, addr, thing) < 0) {
                 HRETURN_ERROR(H5E_CACHE, H5E_CANTFLUSH, NULL,
                               "unable to flush just-loaded object");
             }
@@ -413,6 +524,7 @@ H5AC_flush(H5F_t *f, const H5AC_class_t *type, haddr_t addr, hbool_t destroy)
     cache = f->shared->cache;
 
     if (!H5F_addr_defined(addr)) {
+        unsigned first_flush=1;     /* Indicate if this is the first flush */
 
 #ifdef H5AC_SORT_BY_ADDR
         /*
@@ -457,7 +569,14 @@ H5AC_flush(H5F_t *f, const H5AC_class_t *type, haddr_t addr, hbool_t destroy)
                 H5AC_subid_t type_id=(*info)->type->id;  /* Remember this for later */
 
                 flush = (*info)->type->flush;
-                status = (flush)(f, destroy, (*info)->addr, (*info));
+
+                /* Only block for all the processes on the first piece of metadata */
+                if(first_flush) {
+                    status = (flush)(f, H5AC_dxpl_id, destroy, (*info)->addr, (*info));
+                    first_flush=0;
+                } /* end if */
+                else
+                    status = (flush)(f, H5P_DATASET_XFER_DEFAULT, destroy, (*info)->addr, (*info));
                 if (status < 0) {
 #ifdef H5AC_SORT_BY_ADDR
                     map = H5FL_ARR_FREE(int,map);
@@ -493,7 +612,7 @@ H5AC_flush(H5F_t *f, const H5AC_class_t *type, haddr_t addr, hbool_t destroy)
              * Flush just this entry.
              */
             flush = cache->slot[i]->type->flush;
-            status = (flush)(f, destroy, cache->slot[i]->addr,
+            status = (flush)(f, H5AC_dxpl_id, destroy, cache->slot[i]->addr,
 			     cache->slot[i]);
             if (status < 0) {
                 HRETURN_ERROR(H5E_CACHE, H5E_CANTFLUSH, FAIL,
@@ -567,7 +686,7 @@ H5AC_set(H5F_t *f, const H5AC_class_t *type, haddr_t addr, void *thing)
         H5AC_subid_t type_id=(*info)->type->id;  /* Remember this for later */
 
         flush = (*info)->type->flush;
-        status = (flush)(f, TRUE, (*info)->addr, (*info));
+        status = (flush)(f, H5AC_dxpl_id, TRUE, (*info)->addr, (*info));
         if (status < 0) {
             HRETURN_ERROR(H5E_CACHE, H5E_CANTFLUSH, FAIL,
                           "unable to flush object");
@@ -656,7 +775,7 @@ H5AC_rename(H5F_t *f, const H5AC_class_t *type, haddr_t old_addr,
         H5AC_subid_t type_id=cache->slot[new_idx]->type->id;  /* Remember this for later */
 
         flush = cache->slot[new_idx]->type->flush;
-        status = (flush)(f, TRUE, cache->slot[new_idx]->addr,
+        status = (flush)(f, H5AC_dxpl_id, TRUE, cache->slot[new_idx]->addr,
 			 cache->slot[new_idx]);
         if (status < 0) {
             HRETURN_ERROR(H5E_CACHE, H5E_CANTFLUSH, FAIL,
@@ -774,7 +893,7 @@ H5AC_protect(H5F_t *f, const H5AC_class_t *type, haddr_t addr,
          * without preempting anything.
          */
         cache->diagnostics[type->id].nmisses++;
-        if (NULL == (thing = (type->load)(f, addr, udata1, udata2))) {
+        if (NULL == (thing = (type->load)(f, H5P_DATASET_XFER_DEFAULT, addr, udata1, udata2))) {
             HRETURN_ERROR(H5E_CACHE, H5E_CANTLOAD, NULL,
                           "unable to load object");
         }
@@ -860,7 +979,7 @@ H5AC_unprotect(H5F_t *f, const H5AC_class_t *type, haddr_t addr, void *thing)
 
         assert(H5F_addr_ne((*info)->addr, addr));
         flush = (*info)->type->flush;
-        status = (flush)(f, TRUE, (*info)->addr, (*info));
+        status = (flush)(f, H5AC_dxpl_id, TRUE, (*info)->addr, (*info));
         if (status < 0) {
             HRETURN_ERROR(H5E_CACHE, H5E_CANTFLUSH, FAIL,
                           "unable to flush object");
diff --git a/src/H5ACprivate.h b/src/H5ACprivate.h
index d96fb5e..734e56a 100644
--- a/src/H5ACprivate.h
+++ b/src/H5ACprivate.h
@@ -58,8 +58,8 @@ typedef enum H5AC_subid_t {
     H5AC_NTYPES		= 5	/*THIS MUST BE LAST!			     */
 } H5AC_subid_t;
 
-typedef void *(*H5AC_load_func_t)(H5F_t*, haddr_t addr, const void *udata1, void *udata2);
-typedef herr_t (*H5AC_flush_func_t)(H5F_t*, hbool_t dest, haddr_t addr, void *thing);
+typedef void *(*H5AC_load_func_t)(H5F_t*, hid_t dxpl_id, haddr_t addr, const void *udata1, void *udata2);
+typedef herr_t (*H5AC_flush_func_t)(H5F_t*, hid_t dxpl_id, hbool_t dest, haddr_t addr, void *thing);
 
 typedef struct H5AC_class_t {
     H5AC_subid_t	id;
@@ -107,6 +107,13 @@ typedef struct H5AC_t {
     } diagnostics[H5AC_NTYPES];		/*diagnostics for each type of object*/
 } H5AC_t;
 
+#ifdef H5_HAVE_PARALLEL
+/* Definitions for "block before metadata write" property */
+#define H5AC_BLOCK_BEFORE_META_WRITE_NAME       "H5AC_block_before_meta_write"
+#define H5AC_BLOCK_BEFORE_META_WRITE_SIZE       sizeof(unsigned)
+#define H5AC_BLOCK_BEFORE_META_WRITE_DEF        0
+#endif /* H5_HAVE_PARALLEL */
+
 /*
  * Library prototypes.
  */
diff --git a/src/H5B.c b/src/H5B.c
index 244efa6..a17004f 100644
--- a/src/H5B.c
+++ b/src/H5B.c
@@ -118,8 +118,8 @@ static H5B_ins_t H5B_insert_helper(H5F_t *f, haddr_t addr,
 static herr_t H5B_insert_child(H5F_t *f, const H5B_class_t *type,
 			       H5B_t *bt, int idx, haddr_t child,
 			       H5B_ins_t anchor, void *md_key);
-static herr_t H5B_flush(H5F_t *f, hbool_t destroy, haddr_t addr, H5B_t *b);
-static H5B_t *H5B_load(H5F_t *f, haddr_t addr, const void *_type, void *udata);
+static herr_t H5B_flush(H5F_t *f, hid_t dxpl_id, hbool_t destroy, haddr_t addr, H5B_t *b);
+static H5B_t *H5B_load(H5F_t *f, hid_t dxpl_id, haddr_t addr, const void *_type, void *udata);
 static herr_t H5B_decode_key(H5F_t *f, H5B_t *bt, int idx);
 static herr_t H5B_decode_keys(H5F_t *f, H5B_t *bt, int idx);
 static size_t H5B_nodesize(H5F_t *f, const H5B_class_t *type,
@@ -137,8 +137,8 @@ static herr_t H5B_assert(H5F_t *f, haddr_t addr, const H5B_class_t *type,
 /* H5B inherits cache-like properties from H5AC */
 static const H5AC_class_t H5AC_BT[1] = {{
     H5AC_BT_ID,
-    (void *(*)(H5F_t*, haddr_t, const void*, void*))H5B_load,
-    (herr_t (*)(H5F_t*, hbool_t, haddr_t, void*))H5B_flush,
+    (H5AC_load_func_t)H5B_load,
+    (H5AC_flush_func_t)H5B_flush,
 }};
 
 /* Interface initialization? */
@@ -343,10 +343,14 @@ H5B_Kvalue(H5F_t *f, const H5B_class_t *type)
  * Modifications:
  *		Robb Matzke, 1999-07-28
  *		The ADDR argument is passed by value.
+ *
+ *	Quincey Koziol, 2002-7-180
+ *	Added dxpl parameter to allow more control over I/O from metadata
+ *      cache.
  *-------------------------------------------------------------------------
  */
 static H5B_t *
-H5B_load(H5F_t *f, haddr_t addr, const void *_type, void *udata)
+H5B_load(H5F_t *f, hid_t dxpl_id, haddr_t addr, const void *_type, void *udata)
 {
     const H5B_class_t	*type = (const H5B_class_t *) _type;
     size_t		total_nkey_size;
@@ -380,7 +384,7 @@ H5B_load(H5F_t *f, haddr_t addr, const void *_type, void *udata)
 	HGOTO_ERROR (H5E_RESOURCE, H5E_NOSPACE, NULL,
 		     "memory allocation failed");
     }
-    if (H5F_block_read(f, H5FD_MEM_BTREE, addr, size, H5P_DATASET_XFER_DEFAULT, bt->page)<0) {
+    if (H5F_block_read(f, H5FD_MEM_BTREE, addr, size, dxpl_id, bt->page)<0) {
 	HGOTO_ERROR(H5E_BTREE, H5E_READERROR, NULL,
 		      "can't read B-tree node");
     }
@@ -456,10 +460,14 @@ H5B_load(H5F_t *f, haddr_t addr, const void *_type, void *udata)
  *
  * 		Robb Matzke, 1999-07-28
  *		The ADDR argument is passed by value.
+ *
+ *	Quincey Koziol, 2002-7-180
+ *	Added dxpl parameter to allow more control over I/O from metadata
+ *      cache.
  *-------------------------------------------------------------------------
  */
 static herr_t
-H5B_flush(H5F_t *f, hbool_t destroy, haddr_t addr, H5B_t *bt)
+H5B_flush(H5F_t *f, hid_t dxpl_id, hbool_t destroy, haddr_t addr, H5B_t *bt)
 {
     int	i;
     size_t	size = 0;
@@ -525,7 +533,7 @@ H5B_flush(H5F_t *f, hbool_t destroy, haddr_t addr, H5B_t *bt)
 	 * bother writing data for the child entries that don't exist or
 	 * for the final unchanged children.
 	 */
-	if (H5F_block_write(f, H5FD_MEM_BTREE, addr, size, H5P_DATASET_XFER_DEFAULT, bt->page)<0) {
+	if (H5F_block_write(f, H5FD_MEM_BTREE, addr, size, dxpl_id, bt->page)<0) {
 	    HRETURN_ERROR(H5E_BTREE, H5E_CANTFLUSH, FAIL,
 			  "unable to save B-tree node to disk");
 	}
diff --git a/src/H5FDmpio.c b/src/H5FDmpio.c
index df4b95c..023057f 100644
--- a/src/H5FDmpio.c
+++ b/src/H5FDmpio.c
@@ -8,11 +8,6 @@
  * Purpose:	This is the MPI-2 I/O driver.
  *
  * Limitations:
- *     	H5FD_mpio_read & H5FD_mpio_write
- *		Eventually these should choose collective or independent i/o
- *		based on a parameter that is passed down to it from H5Dwrite,
- *		rather than the access_parms (which are fixed at the open).
- *
  *	H5FD_mpio_read
  *		One implementation of MPI/MPI-IO causes MPI_Get_count
  *		to return (incorrectly) a negative count. I (who?) added code
@@ -21,6 +16,7 @@
  *		kluge is activated by #ifdef MPI_KLUGE0202.
  */
 #include "H5private.h"		/*library functions			*/
+#include "H5ACprivate.h"        /* Metadata cache */
 #include "H5Eprivate.h"		/*error handling			*/
 #include "H5Fprivate.h"		/*files					*/
 #include "H5FDprivate.h"	/*file driver				  */
@@ -71,9 +67,9 @@ static herr_t H5FD_mpio_query(const H5FD_t *_f1, unsigned long *flags);
 static haddr_t H5FD_mpio_get_eoa(H5FD_t *_file);
 static herr_t H5FD_mpio_set_eoa(H5FD_t *_file, haddr_t addr);
 static haddr_t H5FD_mpio_get_eof(H5FD_t *_file);
-static herr_t H5FD_mpio_read(H5FD_t *_file, H5FD_mem_t type, hid_t fapl_id, haddr_t addr,
+static herr_t H5FD_mpio_read(H5FD_t *_file, H5FD_mem_t type, hid_t dxpl_id, haddr_t addr,
             size_t size, void *buf);
-static herr_t H5FD_mpio_write(H5FD_t *_file, H5FD_mem_t type, hid_t fapl_id, haddr_t addr,
+static herr_t H5FD_mpio_write(H5FD_t *_file, H5FD_mem_t type, hid_t dxpl_id, haddr_t addr,
             size_t size, const void *buf);
 static herr_t H5FD_mpio_flush(H5FD_t *_file, unsigned closing);
 
@@ -1210,6 +1206,7 @@ H5FD_mpio_read(H5FD_t *_file, H5FD_mem_t UNUSED type, hid_t dxpl_id, haddr_t add
     /* Make certain we have the correct type of property list */
     assert(H5I_GENPROP_LST==H5I_get_type(dxpl_id));
     assert(TRUE==H5P_isa_class(dxpl_id,H5P_DATASET_XFER));
+    assert(buf);
 
     /* Portably initialize MPI status variable */
     HDmemset(&mpi_stat,0,sizeof(MPI_Status));
@@ -1484,6 +1481,12 @@ done:
  *              if the first I/O was a collective I/O using MPI derived types
  *              and the next I/O was an independent I/O.
  *
+ *              Quincey Koziol - 2002/07/18
+ *              Added "block_before_meta_write" dataset transfer flag, which
+ *              is set during writes from a metadata cache flush and indicates
+ *              that all the processes must sync up before (one of them)
+ *              writing metadata.
+ *
  *-------------------------------------------------------------------------
  */
 static herr_t
@@ -1496,8 +1499,10 @@ H5FD_mpio_write(H5FD_t *_file, H5FD_mem_t type, hid_t dxpl_id, haddr_t addr,
     MPI_Offset 		 	mpi_off, mpi_disp;
     MPI_Status			mpi_stat;
     MPI_Datatype		buf_type, file_type;
+    int			        mpi_code;	/* MPI return code */
     int         		size_i, bytes_written;
     unsigned			use_view_this_time=0;
+    unsigned		        block_before_meta_write=0;      /* Whether to block before a metadata write */
     H5P_genplist_t *plist;      /* Property list pointer */
     herr_t              	ret_value=SUCCEED;
 
@@ -1512,6 +1517,7 @@ H5FD_mpio_write(H5FD_t *_file, H5FD_mem_t type, hid_t dxpl_id, haddr_t addr,
     /* Make certain we have the correct type of property list */
     assert(H5I_GENPROP_LST==H5I_get_type(dxpl_id));
     assert(TRUE==H5P_isa_class(dxpl_id,H5P_DATASET_XFER));
+    assert(buf);
 
     /* Portably initialize MPI status variable */
     HDmemset(&mpi_stat,0,sizeof(MPI_Status));
@@ -1582,19 +1588,36 @@ H5FD_mpio_write(H5FD_t *_file, H5FD_mem_t type, hid_t dxpl_id, haddr_t addr,
             HGOTO_ERROR(H5E_INTERNAL, H5E_MPI, FAIL, "MPI_File_set_view failed");
     } /* end if */
     
-    /* Only p<round> will do the actual write if all procs in comm write same data */
-    if ((type!=H5FD_MEM_DRAW) && H5_mpi_1_metawrite_g) {
-        if (file->mpi_rank != file->mpi_round) {
+    /* Metadata specific actions */
+    if(type!=H5FD_MEM_DRAW) {
+        /* Check if we need to syncronize all processes before attempting metadata write
+         * (Prevents race condition where the process writing the metadata goes ahead
+         * and writes the metadata to the file before all the processes have
+         * read the data, "transmitting" data from the "future" to the reading
+         * process. -QAK )
+         */
+        if(H5P_exist_plist(plist,H5AC_BLOCK_BEFORE_META_WRITE_NAME)>0)
+            if(H5P_get(plist,H5AC_BLOCK_BEFORE_META_WRITE_NAME,&block_before_meta_write)<0)
+                HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't get H5AC property");
+
+        if(block_before_meta_write)
+            if (MPI_SUCCESS!= (mpi_code=MPI_Barrier(file->comm)))
+                HMPI_GOTO_ERROR(FAIL, "MPI_Barrier failed", mpi_code);
+
+        /* Only p<round> will do the actual write if all procs in comm write same metadata */
+        if (H5_mpi_1_metawrite_g) {
+            if (file->mpi_rank != file->mpi_round) {
 #ifdef H5FDmpio_DEBUG
-            if (H5FD_mpio_Debug[(int)'w']) {
-                fprintf(stdout,
-		    "  proc %d: in H5FD_mpio_write (write omitted)\n",
-		    file->mpi_rank );
-            }
+                if (H5FD_mpio_Debug[(int)'w']) {
+                    fprintf(stdout,
+                        "  proc %d: in H5FD_mpio_write (write omitted)\n",
+                        file->mpi_rank );
+                }
 #endif
-            HGOTO_DONE(SUCCEED) /* skip the actual write */
+                HGOTO_DONE(SUCCEED) /* skip the actual write */
+            }
         }
-    }
+    } /* end if */
 
     /* Write the data. */
     assert(H5FD_MPIO_INDEPENDENT==dx->xfer_mode || H5FD_MPIO_COLLECTIVE==dx->xfer_mode);
@@ -1681,18 +1704,6 @@ done:
 
             /* Round-robin rotate to the next process */
             file->mpi_round = (++file->mpi_round)%file->mpi_size;
-#ifdef QAK
-    {
-        int max,min;
-
-        MPI_Allreduce(&file->mpi_round, &max, 1, MPI_INT, MPI_MAX, file->comm);
-        MPI_Allreduce(&file->mpi_round, &min, 1, MPI_INT, MPI_MIN, file->comm);
-        if(max!=file->mpi_round)
-            printf("%s: rank=%d, round=%d, max=%d\n",FUNC,file->mpi_rank,file->mpi_round,max);
-        if(min!=file->mpi_round)
-            printf("%s: rank=%d, round=%d, min=%d\n",FUNC,file->mpi_rank,file->mpi_round,min);
-    }
-#endif /* QAK */
         } /* end if */
     } /* end if */
 
diff --git a/src/H5FDmpiposix.c b/src/H5FDmpiposix.c
index 82533d0..32e5535 100644
--- a/src/H5FDmpiposix.c
+++ b/src/H5FDmpiposix.c
@@ -32,6 +32,7 @@
  *
  */
 #include "H5private.h"		/*library functions			*/
+#include "H5ACprivate.h"        /* Metadata cache */
 #include "H5Eprivate.h"		/*error handling			*/
 #include "H5Fprivate.h"		/*files					*/
 #include "H5FDprivate.h"	/*file driver			        */
@@ -965,21 +966,31 @@ done:
  *
  * Modifications:
  *
+ *              Quincey Koziol - 2002/07/18
+ *              Added "block_before_meta_write" dataset transfer flag, which
+ *              is set during writes from a metadata cache flush and indicates
+ *              that all the processes must sync up before (one of them)
+ *              writing metadata.
+ *
  *-------------------------------------------------------------------------
  */
 static herr_t
-H5FD_mpiposix_write(H5FD_t *_file, H5FD_mem_t type, hid_t UNUSED dxpl_id, haddr_t addr,
+H5FD_mpiposix_write(H5FD_t *_file, H5FD_mem_t type, hid_t dxpl_id, haddr_t addr,
 		size_t size, const void *buf)
 {
     H5FD_mpiposix_t	*file = (H5FD_mpiposix_t*)_file;
     int			mpi_code;	/* MPI return code */
     ssize_t	        nbytes;         /* Number of bytes written each I/O call */
+    H5P_genplist_t      *plist;         /* Property list pointer */
+    unsigned		block_before_meta_write=0;      /* Whether to block before a metadata write */
     herr_t             	ret_value=SUCCEED;      /* Return value */
 
     FUNC_ENTER_NOAPI(H5FD_mpiposix_write, FAIL);
 
     assert(file);
     assert(H5FD_MPIPOSIX==file->pub.driver_id);
+    assert(H5I_GENPROP_LST==H5I_get_type(dxpl_id));
+    assert(TRUE==H5P_isa_class(dxpl_id,H5P_DATASET_XFER));
     assert(buf);
 
     /* Check for overflow conditions */
@@ -990,17 +1001,36 @@ H5FD_mpiposix_write(H5FD_t *_file, H5FD_mem_t type, hid_t UNUSED dxpl_id, haddr_
     if (addr+size>file->eoa)
         HGOTO_ERROR(H5E_ARGS, H5E_OVERFLOW, FAIL, "addr overflow");
     
-    /* Only p<round> will do the actual write if all procs in comm write same data */
-    if ((type!=H5FD_MEM_DRAW) && H5_mpiposix_1_metawrite_g) {
-        if (file->mpi_rank != file->mpi_round)
-            HGOTO_DONE(SUCCEED) /* skip the actual write */
+    /* Obtain the data transfer properties */
+    if(NULL == (plist = H5I_object(dxpl_id)))
+        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not a file access property list");
+
+    /* Metadata specific actions */
+    if(type!=H5FD_MEM_DRAW) {
+        /* Check if we need to syncronize all processes before attempting metadata write
+         * (Prevents race condition where the process writing the metadata goes ahead
+         * and writes the metadata to the file before all the processes have
+         * read the data, "transmitting" data from the "future" to the reading
+         * process. -QAK )
+         */
+        if(H5P_exist_plist(plist,H5AC_BLOCK_BEFORE_META_WRITE_NAME)>0)
+            if(H5P_get(plist,H5AC_BLOCK_BEFORE_META_WRITE_NAME,&block_before_meta_write)<0)
+                HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't get H5AC property");
+
+        if(block_before_meta_write)
+            if (MPI_SUCCESS!= (mpi_code=MPI_Barrier(file->comm)))
+                HMPI_GOTO_ERROR(FAIL, "MPI_Barrier failed", mpi_code);
+
+        /* Only p<round> will do the actual write if all procs in comm write same metadata */
+        if (H5_mpiposix_1_metawrite_g)
+            if (file->mpi_rank != file->mpi_round)
+                HGOTO_DONE(SUCCEED) /* skip the actual write */
     } /* end if */
 
     /* Seek to the correct location */
     if ((addr!=file->pos || OP_WRITE!=file->op) &&
             file_seek(file->fd, (file_offset_t)addr, SEEK_SET)<0)
-        HGOTO_ERROR(H5E_IO, H5E_SEEKERROR, FAIL,
-		      "unable to seek to proper position");
+        HGOTO_ERROR(H5E_IO, H5E_SEEKERROR, FAIL, "unable to seek to proper position");
 
     /*
      * Write the data, being careful of interrupted system calls and partial
@@ -1039,18 +1069,6 @@ done:
 
             /* Round-robin rotate to the next process */
             file->mpi_round = (++file->mpi_round)%file->mpi_size;
-#ifdef QAK
-    {
-        int max,min;
-
-        MPI_Allreduce(&file->mpi_round, &max, 1, MPI_INT, MPI_MAX, file->comm);
-        MPI_Allreduce(&file->mpi_round, &min, 1, MPI_INT, MPI_MIN, file->comm);
-        if(max!=file->mpi_round)
-            printf("%s: rank=%d, round=%d, max=%d\n",FUNC,file->mpi_rank,file->mpi_round,max);
-        if(min!=file->mpi_round)
-            printf("%s: rank=%d, round=%d, min=%d\n",FUNC,file->mpi_rank,file->mpi_round,min);
-    }
-#endif /* QAK */
         } /* end if */
     } /* end else */
 
diff --git a/src/H5Gnode.c b/src/H5Gnode.c
index 2acd0a4..efb38d0 100644
--- a/src/H5Gnode.c
+++ b/src/H5Gnode.c
@@ -46,9 +46,9 @@ static size_t H5G_node_size(H5F_t *f);
 static herr_t H5G_node_create(H5F_t *f, H5B_ins_t op, void *_lt_key,
 			      void *_udata, void *_rt_key,
 			      haddr_t *addr_p/*out*/);
-static herr_t H5G_node_flush(H5F_t *f, hbool_t destroy, haddr_t addr,
+static herr_t H5G_node_flush(H5F_t *f, hid_t dxpl_id, hbool_t destroy, haddr_t addr,
 			     H5G_node_t *sym);
-static H5G_node_t *H5G_node_load(H5F_t *f, haddr_t addr, const void *_udata1,
+static H5G_node_t *H5G_node_load(H5F_t *f, hid_t dxpl_id, haddr_t addr, const void *_udata1,
 				 void *_udata2);
 static int H5G_node_cmp2(H5F_t *f, void *_lt_key, void *_udata,
 			  void *_rt_key);
@@ -70,7 +70,7 @@ static size_t H5G_node_sizeof_rkey(H5F_t *f, const void *_udata);
 const H5AC_class_t H5AC_SNODE[1] = {{
     H5AC_SNODE_ID,
     (H5AC_load_func_t)H5G_node_load,
-    (herr_t (*)(H5F_t*, hbool_t, haddr_t, void*))H5G_node_flush,
+    (H5AC_flush_func_t)H5G_node_flush,
 }};
 
 /* H5G inherits B-tree like properties from H5B */
@@ -315,10 +315,14 @@ H5G_node_create(H5F_t *f, H5B_ins_t UNUSED op, void *_lt_key,
  *
  * 		Robb Matzke, 1999-07-28
  *		The ADDR argument is passed by value.
+ *
+ *	Quincey Koziol, 2002-7-180
+ *	Added dxpl parameter to allow more control over I/O from metadata
+ *      cache.
  *-------------------------------------------------------------------------
  */
 static herr_t
-H5G_node_flush(H5F_t *f, hbool_t destroy, haddr_t addr, H5G_node_t *sym)
+H5G_node_flush(H5F_t *f, hid_t dxpl_id, hbool_t destroy, haddr_t addr, H5G_node_t *sym)
 {
     uint8_t	*buf = NULL, *p = NULL;
     size_t	size;
@@ -376,7 +380,7 @@ H5G_node_flush(H5F_t *f, hbool_t destroy, haddr_t addr, H5G_node_t *sym)
         H5G_ent_encode_vec(f, &p, sym->entry, sym->nsyms);
         HDmemset(p, 0, size - (p - buf));
 
-        status = H5F_block_write(f, H5FD_MEM_BTREE, addr, size, H5P_DATASET_XFER_DEFAULT, buf);
+        status = H5F_block_write(f, H5FD_MEM_BTREE, addr, size, dxpl_id, buf);
         if (status < 0)
             HRETURN_ERROR(H5E_SYM, H5E_WRITEERROR, FAIL,
                   "unable to write symbol table node to the file");
@@ -415,10 +419,14 @@ H5G_node_flush(H5F_t *f, hbool_t destroy, haddr_t addr, H5G_node_t *sym)
  * Modifications:
  *		Robb Matzke, 1999-07-28
  *		The ADDR argument is passed by value.
+ *
+ *	Quincey Koziol, 2002-7-180
+ *	Added dxpl parameter to allow more control over I/O from metadata
+ *      cache.
  *-------------------------------------------------------------------------
  */
 static H5G_node_t *
-H5G_node_load(H5F_t *f, haddr_t addr, const void * UNUSED _udata1,
+H5G_node_load(H5F_t *f, hid_t dxpl_id, haddr_t addr, const void * UNUSED _udata1,
 	      void * UNUSED _udata2)
 {
     H5G_node_t		   *sym = NULL;
@@ -450,9 +458,9 @@ H5G_node_load(H5F_t *f, haddr_t addr, const void * UNUSED _udata1,
 	HGOTO_ERROR (H5E_RESOURCE, H5E_NOSPACE, NULL,
 		     "memory allocation failed");
     }
-    if (H5F_block_read(f, H5FD_MEM_BTREE, addr, size, H5P_DATASET_XFER_DEFAULT, buf) < 0) {
+    if (H5F_block_read(f, H5FD_MEM_BTREE, addr, size, dxpl_id, buf) < 0) {
 	HGOTO_ERROR(H5E_SYM, H5E_READERROR, NULL,
-		    "unabel to read symbol table node");
+		    "unable to read symbol table node");
     }
     /* magic */
     if (HDmemcmp(p, H5G_NODE_MAGIC, H5G_NODE_SIZEOF_MAGIC)) {
diff --git a/src/H5HG.c b/src/H5HG.c
index 34ed1cf..5920e15 100644
--- a/src/H5HG.c
+++ b/src/H5HG.c
@@ -56,9 +56,9 @@ struct H5HG_heap_t {
 };
 
 /* PRIVATE PROTOTYPES */
-static H5HG_heap_t *H5HG_load(H5F_t *f, haddr_t addr, const void *udata1,
+static H5HG_heap_t *H5HG_load(H5F_t *f, hid_t dxpl_id, haddr_t addr, const void *udata1,
 			      void *udata2);
-static herr_t H5HG_flush(H5F_t *f, hbool_t dest, haddr_t addr,
+static herr_t H5HG_flush(H5F_t *f, hid_t dxpl_id, hbool_t dest, haddr_t addr,
 			 H5HG_heap_t *heap);
 
 /*
@@ -66,8 +66,8 @@ static herr_t H5HG_flush(H5F_t *f, hbool_t dest, haddr_t addr,
  */
 static const H5AC_class_t H5AC_GHEAP[1] = {{
     H5AC_GHEAP_ID,
-    (void *(*)(H5F_t*, haddr_t, const void*, void*))H5HG_load,
-    (herr_t (*)(H5F_t*, hbool_t, haddr_t, void*))H5HG_flush,
+    (H5AC_load_func_t)H5HG_load,
+    (H5AC_flush_func_t)H5HG_flush,
 }};
 
 /* Interface initialization */
@@ -221,10 +221,14 @@ H5HG_create (H5F_t *f, size_t size)
  * Modifications:
  *		Robb Matzke, 1999-07-28
  *		The ADDR argument is passed by value.
+ *
+ *	Quincey Koziol, 2002-7-180
+ *	Added dxpl parameter to allow more control over I/O from metadata
+ *      cache.
  *-------------------------------------------------------------------------
  */
 static H5HG_heap_t *
-H5HG_load (H5F_t *f, haddr_t addr, const void * UNUSED udata1,
+H5HG_load (H5F_t *f, hid_t dxpl_id, haddr_t addr, const void * UNUSED udata1,
 	   void * UNUSED udata2)
 {
     H5HG_heap_t	*heap = NULL;
@@ -251,7 +255,7 @@ H5HG_load (H5F_t *f, haddr_t addr, const void * UNUSED udata1,
 	HGOTO_ERROR (H5E_RESOURCE, H5E_NOSPACE, NULL,
 		     "memory allocation failed");
     }
-    if (H5F_block_read(f, H5FD_MEM_GHEAP, addr, H5HG_MINSIZE, H5P_DATASET_XFER_DEFAULT,
+    if (H5F_block_read(f, H5FD_MEM_GHEAP, addr, H5HG_MINSIZE, dxpl_id,
 		       heap->chunk)<0) {
 	HGOTO_ERROR (H5E_HEAP, H5E_READERROR, NULL,
 		     "unable to read global heap collection");
@@ -288,7 +292,7 @@ H5HG_load (H5F_t *f, haddr_t addr, const void * UNUSED udata1,
 			 "memory allocation failed");
 	}
 	if (H5F_block_read (f, H5FD_MEM_GHEAP, next_addr, (heap->size-H5HG_MINSIZE),
-			    H5P_DATASET_XFER_DEFAULT, heap->chunk+H5HG_MINSIZE)<0) {
+			    dxpl_id, heap->chunk+H5HG_MINSIZE)<0) {
 	    HGOTO_ERROR (H5E_HEAP, H5E_READERROR, NULL,
 			 "unable to read global heap collection");
 	}
@@ -397,10 +401,14 @@ H5HG_load (H5F_t *f, haddr_t addr, const void * UNUSED udata1,
  * Modifications:
  *		Robb Matzke, 1999-07-28
  *		The ADDR argument is passed by value.
+ *
+ *	Quincey Koziol, 2002-7-180
+ *	Added dxpl parameter to allow more control over I/O from metadata
+ *      cache.
  *-------------------------------------------------------------------------
  */
 static herr_t
-H5HG_flush (H5F_t *f, hbool_t destroy, haddr_t addr, H5HG_heap_t *heap)
+H5HG_flush (H5F_t *f, hid_t dxpl_id, hbool_t destroy, haddr_t addr, H5HG_heap_t *heap)
 {
     int		i;
     
@@ -414,7 +422,7 @@ H5HG_flush (H5F_t *f, hbool_t destroy, haddr_t addr, H5HG_heap_t *heap)
 
     if (heap->dirty) {
 	if (H5F_block_write (f, H5FD_MEM_GHEAP, addr, heap->size,
-			     H5P_DATASET_XFER_DEFAULT, heap->chunk)<0) {
+			     dxpl_id, heap->chunk)<0) {
 	    HRETURN_ERROR (H5E_HEAP, H5E_WRITEERROR, FAIL,
 			   "unable to write global heap collection to file");
 	}
diff --git a/src/H5HL.c b/src/H5HL.c
index 60ded72..45d8f0f 100644
--- a/src/H5HL.c
+++ b/src/H5HL.c
@@ -52,17 +52,17 @@ typedef struct H5HL_t {
 } H5HL_t;
 
 /* PRIVATE PROTOTYPES */
-static H5HL_t *H5HL_load(H5F_t *f, haddr_t addr, const void *udata1,
+static H5HL_t *H5HL_load(H5F_t *f, hid_t dxpl_id, haddr_t addr, const void *udata1,
 			 void *udata2);
-static herr_t H5HL_flush(H5F_t *f, hbool_t dest, haddr_t addr, H5HL_t *heap);
+static herr_t H5HL_flush(H5F_t *f, hid_t dxpl_id, hbool_t dest, haddr_t addr, H5HL_t *heap);
 
 /*
  * H5HL inherits cache-like properties from H5AC
  */
 static const H5AC_class_t H5AC_LHEAP[1] = {{
     H5AC_LHEAP_ID,
-    (void *(*)(H5F_t*, haddr_t, const void*, void*))H5HL_load,
-    (herr_t (*)(H5F_t*, hbool_t, haddr_t, void*))H5HL_flush,
+    (H5AC_load_func_t)H5HL_load,
+    (H5AC_flush_func_t)H5HL_flush,
 }};
 
 /* Interface initialization */
@@ -195,10 +195,14 @@ H5HL_create(H5F_t *f, size_t size_hint, haddr_t *addr_p/*out*/)
  * Modifications:
  *		Robb Matzke, 1999-07-28
  *		The ADDR argument is passed by value.
+ *
+ *	Quincey Koziol, 2002-7-180
+ *	Added dxpl parameter to allow more control over I/O from metadata
+ *      cache.
  *-------------------------------------------------------------------------
  */
 static H5HL_t *
-H5HL_load(H5F_t *f, haddr_t addr, const void * UNUSED udata1,
+H5HL_load(H5F_t *f, hid_t dxpl_id, haddr_t addr, const void * UNUSED udata1,
 	  void * UNUSED udata2)
 {
     uint8_t		hdr[52];
@@ -217,7 +221,7 @@ H5HL_load(H5F_t *f, haddr_t addr, const void * UNUSED udata1,
     assert(!udata1);
     assert(!udata2);
 
-    if (H5F_block_read(f, H5FD_MEM_LHEAP, addr, H5HL_SIZEOF_HDR(f), H5P_DATASET_XFER_DEFAULT,
+    if (H5F_block_read(f, H5FD_MEM_LHEAP, addr, H5HL_SIZEOF_HDR(f), dxpl_id,
 		       hdr) < 0) {
 	HRETURN_ERROR(H5E_HEAP, H5E_READERROR, NULL,
 		      "unable to read heap header");
@@ -258,7 +262,7 @@ H5HL_load(H5F_t *f, haddr_t addr, const void * UNUSED udata1,
     }
     if (heap->disk_alloc &&
 	H5F_block_read(f, H5FD_MEM_LHEAP, heap->addr, heap->disk_alloc,
-		       H5P_DATASET_XFER_DEFAULT, heap->chunk + H5HL_SIZEOF_HDR(f)) < 0) {
+		       dxpl_id, heap->chunk + H5HL_SIZEOF_HDR(f)) < 0) {
 	HGOTO_ERROR(H5E_HEAP, H5E_CANTLOAD, NULL,
 		    "unable to read heap data");
     }
@@ -323,10 +327,14 @@ H5HL_load(H5F_t *f, haddr_t addr, const void * UNUSED udata1,
  *
  * 		Robb Matzke, 1999-07-28
  *		The ADDR argument is passed by value.
+ *
+ *	Quincey Koziol, 2002-7-180
+ *	Added dxpl parameter to allow more control over I/O from metadata
+ *      cache.
  *-------------------------------------------------------------------------
  */
 static herr_t
-H5HL_flush(H5F_t *f, hbool_t destroy, haddr_t addr, H5HL_t *heap)
+H5HL_flush(H5F_t *f, hid_t dxpl_id, hbool_t destroy, haddr_t addr, H5HL_t *heap)
 {
     uint8_t	*p = heap->chunk;
     H5HL_free_t	*fl = heap->freelist;
@@ -394,19 +402,18 @@ H5HL_flush(H5F_t *f, hbool_t destroy, haddr_t addr, H5HL_t *heap)
 	    /* The header and data are contiguous */
 	    if (H5F_block_write(f, H5FD_MEM_LHEAP, addr,
 				(H5HL_SIZEOF_HDR(f)+heap->disk_alloc),
-				H5P_DATASET_XFER_DEFAULT, heap->chunk) < 0) {
+				dxpl_id, heap->chunk) < 0) {
 		HRETURN_ERROR(H5E_HEAP, H5E_WRITEERROR, FAIL,
 			    "unable to write heap header and data to file");
 	    }
 	} else {
 	    if (H5F_block_write(f, H5FD_MEM_LHEAP, addr, H5HL_SIZEOF_HDR(f),
-				H5P_DATASET_XFER_DEFAULT, heap->chunk)<0) {
+				dxpl_id, heap->chunk)<0) {
 		HRETURN_ERROR(H5E_HEAP, H5E_WRITEERROR, FAIL,
 			      "unable to write heap header to file");
 	    }
 	    if (H5F_block_write(f, H5FD_MEM_LHEAP, heap->addr, heap->disk_alloc,
-				H5P_DATASET_XFER_DEFAULT,
-				heap->chunk + H5HL_SIZEOF_HDR(f)) < 0) {
+				dxpl_id, heap->chunk + H5HL_SIZEOF_HDR(f)) < 0) {
 		HRETURN_ERROR(H5E_HEAP, H5E_WRITEERROR, FAIL,
 			      "unable to write heap data to file");
 	    }
diff --git a/src/H5O.c b/src/H5O.c
index 7081048..827fdad 100644
--- a/src/H5O.c
+++ b/src/H5O.c
@@ -30,8 +30,8 @@
 #define PABLO_MASK	H5O_mask
 
 /* PRIVATE PROTOTYPES */
-static herr_t H5O_flush(H5F_t *f, hbool_t destroy, haddr_t addr, H5O_t *oh);
-static H5O_t *H5O_load(H5F_t *f, haddr_t addr, const void *_udata1,
+static herr_t H5O_flush(H5F_t *f, hid_t dxpl_id, hbool_t destroy, haddr_t addr, H5O_t *oh);
+static H5O_t *H5O_load(H5F_t *f, hid_t dxpl_id, haddr_t addr, const void *_udata1,
 		       void *_udata2);
 static unsigned H5O_find_in_ohdr(H5F_t *f, haddr_t addr,
 			     const H5O_class_t **type_p, int sequence);
@@ -44,8 +44,8 @@ static herr_t H5O_touch_oh(H5F_t *f, H5O_t *oh, hbool_t force);
 /* H5O inherits cache-like properties from H5AC */
 static const H5AC_class_t H5AC_OHDR[1] = {{
     H5AC_OHDR_ID,
-    (void *(*)(H5F_t *, haddr_t, const void *, void *)) H5O_load,
-    (herr_t (*)(H5F_t *, hbool_t, haddr_t, void *)) H5O_flush,
+    (H5AC_load_func_t)H5O_load,
+    (H5AC_flush_func_t)H5O_flush,
 }};
 
 /* Interface initialization */
@@ -339,10 +339,14 @@ H5O_close(H5G_entry_t *obj_ent)
  *
  * 	Robb Matzke, 1999-07-28
  *	The ADDR argument is passed by value.
+ *
+ *	Quincey Koziol, 2002-7-180
+ *	Added dxpl parameter to allow more control over I/O from metadata
+ *      cache.
  *-------------------------------------------------------------------------
  */
 static H5O_t *
-H5O_load(H5F_t *f, haddr_t addr, const void * UNUSED _udata1,
+H5O_load(H5F_t *f, hid_t dxpl_id, haddr_t addr, const void * UNUSED _udata1,
 	 void * UNUSED _udata2)
 {
     H5O_t	*oh = NULL;
@@ -376,7 +380,7 @@ H5O_load(H5F_t *f, haddr_t addr, const void * UNUSED _udata1,
     /* read fixed-lenth part of object header */
     hdr_size = H5O_SIZEOF_HDR(f);
     assert(hdr_size<=sizeof(buf));
-    if (H5F_block_read(f, H5FD_MEM_OHDR, addr, hdr_size, H5P_DATASET_XFER_DEFAULT, buf) < 0) {
+    if (H5F_block_read(f, H5FD_MEM_OHDR, addr, hdr_size, dxpl_id, buf) < 0) {
 	HGOTO_ERROR(H5E_OHDR, H5E_READERROR, NULL,
 		    "unable to read object header");
     }
@@ -434,7 +438,7 @@ H5O_load(H5F_t *f, haddr_t addr, const void * UNUSED _udata1,
 	    HGOTO_ERROR (H5E_RESOURCE, H5E_NOSPACE, NULL,
 			 "memory allocation failed");
 	}
-	if (H5F_block_read(f, H5FD_MEM_OHDR, chunk_addr, chunk_size, H5P_DATASET_XFER_DEFAULT,
+	if (H5F_block_read(f, H5FD_MEM_OHDR, chunk_addr, chunk_size, dxpl_id,
 			   oh->chunk[chunkno].image) < 0) {
 	    HGOTO_ERROR(H5E_OHDR, H5E_READERROR, NULL,
 			"unable to read object header data");
@@ -537,10 +541,14 @@ done:
  *
  * 	Robb Matzke, 1999-07-28
  *	The ADDR argument is passed by value.
+ *
+ *	Quincey Koziol, 2002-7-180
+ *	Added dxpl parameter to allow more control over I/O from metadata
+ *      cache.
  *-------------------------------------------------------------------------
  */
 static herr_t
-H5O_flush(H5F_t *f, hbool_t destroy, haddr_t addr, H5O_t *oh)
+H5O_flush(H5F_t *f, hid_t dxpl_id, hbool_t destroy, haddr_t addr, H5O_t *oh)
 {
     uint8_t	buf[16], *p;
     int	id;
@@ -586,7 +594,7 @@ H5O_flush(H5F_t *f, hbool_t destroy, haddr_t addr, H5O_t *oh)
         } /* end if */
         else {
             if (H5F_block_write(f, H5FD_MEM_OHDR, addr, H5O_SIZEOF_HDR(f), 
-                        H5P_DATASET_XFER_DEFAULT, buf) < 0) {
+                        dxpl_id, buf) < 0) {
                 HRETURN_ERROR(H5E_OHDR, H5E_WRITEERROR, FAIL,
                       "unable to write object header hdr to disk");
             }
@@ -669,7 +677,7 @@ H5O_flush(H5F_t *f, hbool_t destroy, haddr_t addr, H5O_t *oh)
                     /* Write the combined prefix/chunk out */
                     if (H5F_block_write(f, H5FD_MEM_OHDR, addr,
                                 (H5O_SIZEOF_HDR(f)+oh->chunk[u].size),
-                                H5P_DATASET_XFER_DEFAULT, p) < 0) {
+                                dxpl_id, p) < 0) {
                         HRETURN_ERROR(H5E_OHDR, H5E_WRITEERROR, FAIL,
                               "unable to write object header data to disk");
                     } /* end if */
@@ -680,7 +688,7 @@ H5O_flush(H5F_t *f, hbool_t destroy, haddr_t addr, H5O_t *oh)
                 else {
                     if (H5F_block_write(f, H5FD_MEM_OHDR, oh->chunk[u].addr,
                                 (oh->chunk[u].size),
-                                H5P_DATASET_XFER_DEFAULT, oh->chunk[u].image) < 0) {
+                                dxpl_id, oh->chunk[u].image) < 0) {
                         HRETURN_ERROR(H5E_OHDR, H5E_WRITEERROR, FAIL,
                               "unable to write object header data to disk");
                     } /* end if */
diff --git a/src/H5private.h b/src/H5private.h
index 65b37c3..765eb16 100644
--- a/src/H5private.h
+++ b/src/H5private.h
@@ -1181,6 +1181,7 @@ __DLL__ void H5_term_library(void);
 
 /* Functions to terminate interfaces */
 __DLL__ int H5A_term_interface(void);
+__DLL__ int H5AC_term_interface(void);
 __DLL__ int H5D_term_interface(void);
 __DLL__ int H5F_term_interface(void);
 __DLL__ int H5G_term_interface(void);