Improve transaction support, add H5Fcreate_ff, H5Fopen_ff, H5Fclose_ff.

6 files changed, 436 insertions, 97 deletions

diff --git a/src/H5FF.c b/src/H5FF.c
index b65b200..649d84f 100644
--- a/src/H5FF.c
+++ b/src/H5FF.c
@@ -24,11 +24,11 @@
 
 #include "H5FFmodule.h"         /* This source code file is part of the H5FF module */
 
-#define H5A_FRIEND		/*suppress error about including H5Apkg	  */
+//#define H5A_FRIEND		/*suppress error about including H5Apkg	  */
 #define H5D_FRIEND		/*suppress error about including H5Dpkg	  */
 #define H5F_FRIEND		/*suppress error about including H5Fpkg	  */
-#define H5G_FRIEND		/*suppress error about including H5Gpkg	  */
-#define H5T_FRIEND		/*suppress error about including H5Tpkg	  */
+//#define H5G_FRIEND		/*suppress error about including H5Gpkg	  */
+//#define H5T_FRIEND		/*suppress error about including H5Tpkg	  */
 
 
 /***********/
@@ -45,6 +45,7 @@
 #include "H5MMprivate.h"        /* Memory management                    */
 #include "H5Pprivate.h"         /* Property lists                       */
 //#include "H5Tpkg.h"             /* Datatype access                      */
+#include "H5TRprivate.h"        /* Transactions                         */
 
 #include "H5VLdaosm.h"          /* IOD plugin - tmp                     */
 
@@ -52,7 +53,8 @@
 /****************/
 /* Local Macros */
 /****************/
-H5FL_EXTERN(H5RC_t);
+H5FL_EXTERN(H5TR_t);
+H5FL_EXTERN(H5VL_t);
 
 /******************/
 /* Local Typedefs */
@@ -91,25 +93,272 @@ H5FF__init_package(void)
         HDONE_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "unable to init file interface")
 
     /*if(H5G_init() < 0)
-        HDONE_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "unable to init group interface")
+        HDONE_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "unable to init group interface")*/
 
     if(H5D_init() < 0)
         HDONE_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "unable to init dataset interface")
 
-    if(H5A_init() < 0)
+    /*if(H5A_init() < 0)
         HDONE_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "unable to init attribute interface")
 
     if(H5M_init() < 0)
-        HDONE_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "unable to init map interface")
-
-    if(H5RC_init() < 0)
         HDONE_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "unable to init map interface") DSMINC*/
 
+    if(H5TR_init() < 0)
+        HDONE_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "unable to init map interface")
+
     FUNC_LEAVE_NOAPI(ret_value)
 } /* H5FF__init_package() */
 
 
 /*-------------------------------------------------------------------------
+ * Function:    H5Fcreate_ff
+ *
+ * Purpose:     Asynchronous wrapper around H5Fcreate(). If requested,
+ *              trans_id returns the transaction used to create the file,
+ *              uncommitted. If trans_id is NULL, the transaction used to
+ *              create the file will be committed.
+ *
+ * Return:      Success:        The placeholder ID for a new file.  When
+ *                              the asynchronous operation completes, this
+ *                              ID will transparently be modified to be a
+ *                              "normal" ID.
+ *              Failure:        FAIL
+ *
+ * Programmer:  Neil Fortner
+ *              Monday, November 14, 2016
+ *
+ *-------------------------------------------------------------------------
+ */
+hid_t
+H5Fcreate_ff(const char *filename, unsigned flags, hid_t fcpl_id, hid_t fapl_id,
+    hid_t *trans_id)
+{
+    void    *file = NULL;            /* file token from VOL plugin */
+    H5P_genplist_t *plist;        /* Property list pointer */
+    H5VL_plugin_prop_t plugin_prop;         /* Property for vol plugin ID & info */
+    H5VL_class_t *vol_cls = NULL; /* VOL Class structure for callback info */
+    H5VL_t *vol_info = NULL;      /* VOL info struct */
+    hid_t    ret_value;              /* Return value */
+
+    FUNC_ENTER_API(FAIL)
+
+    /* Check/fix arguments */
+    if(!filename || !*filename)
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "invalid file name")
+    /* In this routine, we only accept the following flags:
+     *          H5F_ACC_EXCL, H5F_ACC_TRUNC and H5F_ACC_DEBUG
+     */
+    if(flags & ~(H5F_ACC_EXCL | H5F_ACC_TRUNC | H5F_ACC_DEBUG))
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "invalid flags")
+    /* The H5F_ACC_EXCL and H5F_ACC_TRUNC flags are mutually exclusive */
+    if((flags & H5F_ACC_EXCL) && (flags & H5F_ACC_TRUNC))
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "mutually exclusive flags for file creation")
+
+    /* Check file creation property list */
+    if(H5P_DEFAULT == fcpl_id)
+        fcpl_id = H5P_FILE_CREATE_DEFAULT;
+    else
+        if(TRUE != H5P_isa_class(fcpl_id, H5P_FILE_CREATE))
+            HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not file create property list")
+
+    /* Check the file access property list */
+    if(H5P_DEFAULT == fapl_id)
+        fapl_id = H5P_FILE_ACCESS_DEFAULT;
+    else
+        if(TRUE != H5P_isa_class(fapl_id, H5P_FILE_ACCESS))
+            HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not file access property list")
+
+    /* get the VOL info from the fapl */
+    if(NULL == (plist = (H5P_genplist_t *)H5I_object(fapl_id)))
+        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not a file access property list")
+
+    if(H5P_peek(plist, H5F_ACS_VOL_NAME, &plugin_prop) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't get vol plugin info")
+
+    if(NULL == (vol_cls = (H5VL_class_t *)H5I_object_verify(plugin_prop.plugin_id, H5I_VOL)))
+        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not a VOL plugin ID")
+
+    /* Determine if we want to acquire the transaction used to create the file
+     */
+    if(trans_id) {
+        H5TR_t *tr = NULL;
+
+        /* Allocate transaction struct */
+        if(NULL == (tr = H5FL_CALLOC(H5TR_t)))
+            HGOTO_ERROR(H5E_SYM, H5E_NOSPACE, FAIL, "can't allocate transaction structure")
+
+        tr->file = NULL;
+        tr->epoch = DAOS_EPOCH_MAX;
+        tr->vol_cls = vol_cls;
+
+        /* Get an atom for the transaction */
+        if((*trans_id = H5I_register(H5I_TR, tr, TRUE)) < 0)
+            HGOTO_ERROR(H5E_ATOM, H5E_CANTREGISTER, FAIL, "unable to atomize transaction handle");
+
+        /* Get the plist structure */
+        if(NULL == (plist = (H5P_genplist_t *)H5I_object(fapl_id)))
+            HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, FAIL, "can't find object for ID")
+        if(H5P_set(plist, H5VL_ACQUIRE_TR_ID, trans_id) < 0)
+            HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't set property value for trans id")
+    } /* end if */
+
+    /* create a new file or truncate an existing file through the VOL */
+    if(NULL == (file = H5VL_file_create(vol_cls, filename, flags, fcpl_id, fapl_id, 
+                                        H5AC_ind_read_dxpl_id, NULL)))
+        HGOTO_ERROR(H5E_FILE, H5E_CANTOPENFILE, FAIL, "unable to create file")
+
+    /* setup VOL info struct */
+    if(NULL == (vol_info = H5FL_CALLOC(H5VL_t)))
+        HGOTO_ERROR(H5E_FILE, H5E_NOSPACE, FAIL, "can't allocate VL info struct")
+    vol_info->vol_cls = vol_cls;
+    vol_info->vol_id = plugin_prop.plugin_id;
+    if(H5I_inc_ref(vol_info->vol_id, FALSE) < 0)
+        HGOTO_ERROR(H5E_ATOM, H5E_CANTINC, FAIL, "unable to increment ref count on VOL plugin")
+
+    /* Get an atom for the file */
+    if((ret_value = H5VL_register_id(H5I_FILE, file, vol_info, TRUE)) < 0)
+        HGOTO_ERROR(H5E_ATOM, H5E_CANTREGISTER, FAIL, "unable to atomize file handle")
+
+done:
+    FUNC_LEAVE_API(ret_value)
+} /* end H5Fcreate_ff() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:    H5Fopen_ff
+ *
+ * Purpose:     Asynchronous wrapper around H5Fcreate(). If requested,
+ *              trans_id returns the highest committed transaction for the
+ *              file.
+ *
+ * Return:      Success:        The placeholder ID for a new file.  When
+ *                              the asynchronous operation completes, this
+ *                              ID will transparently be modified to be a
+ *                              "normal" ID.
+ *              Failure:        FAIL
+ *
+ * Programmer:  Neil Fortner
+ *              Monday, November 14, 2016
+ *
+ *-------------------------------------------------------------------------
+ */
+hid_t
+H5Fopen_ff(const char *filename, unsigned flags, hid_t fapl_id, hid_t *trans_id)
+{
+    void    *file = NULL;            /* file token from VOL plugin */
+    H5P_genplist_t *plist;        /* Property list pointer */
+    H5VL_plugin_prop_t plugin_prop;         /* Property for vol plugin ID & info */
+    H5VL_class_t *vol_cls = NULL; /* VOL Class structure for callback info */
+    H5VL_t *vol_info = NULL;      /* VOL info struct */
+    hid_t    ret_value;              /* Return value */
+
+    FUNC_ENTER_API(FAIL)
+
+    /* Check/fix arguments */
+    if(!filename || !*filename)
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "invalid file name")
+    /* Reject undefined flags (~H5F_ACC_PUBLIC_FLAGS) and the H5F_ACC_TRUNC & H5F_ACC_EXCL flags */
+    if((flags & ~H5F_ACC_PUBLIC_FLAGS) ||
+            (flags & H5F_ACC_TRUNC) || (flags & H5F_ACC_EXCL))
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "invalid file open flags")
+
+    /* Check the file access property list */
+    if(H5P_DEFAULT == fapl_id)
+        fapl_id = H5P_FILE_ACCESS_DEFAULT;
+    else
+        if(TRUE != H5P_isa_class(fapl_id, H5P_FILE_ACCESS))
+            HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not file access property list")
+
+    /* get the VOL info from the fapl */
+    if(NULL == (plist = (H5P_genplist_t *)H5I_object(fapl_id)))
+        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not a file access property list")
+
+    if(H5P_peek(plist, H5F_ACS_VOL_NAME, &plugin_prop) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't get vol plugin info")
+
+    if(NULL == (vol_cls = (H5VL_class_t *)H5I_object_verify(plugin_prop.plugin_id, H5I_VOL)))
+        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not a VOL plugin ID")
+
+    /* Determine if we want to acquire the highest committed transaction when
+     * the file is opened */
+    if(trans_id) {
+        H5TR_t *tr = NULL;
+
+        /* Allocate transaction struct */
+        if(NULL == (tr = H5FL_CALLOC(H5TR_t)))
+            HGOTO_ERROR(H5E_SYM, H5E_NOSPACE, FAIL, "can't allocate transaction structure")
+
+        tr->file = NULL;
+        tr->epoch = DAOS_EPOCH_MAX;
+        tr->vol_cls = vol_cls;
+
+        /* Get an atom for the transaction */
+        if((*trans_id = H5I_register(H5I_TR, tr, TRUE)) < 0)
+            HGOTO_ERROR(H5E_ATOM, H5E_CANTREGISTER, FAIL, "unable to atomize transaction handle");
+
+        /* Get the plist structure */
+        if(NULL == (plist = (H5P_genplist_t *)H5I_object(fapl_id)))
+            HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, FAIL, "can't find object for ID")
+        if(H5P_set(plist, H5VL_ACQUIRE_TR_ID, trans_id) < 0)
+            HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, FAIL, "can't set property value for trans id")
+    } /* end if */
+
+    /* create a new file or truncate an existing file through the VOL */
+    if(NULL == (file = H5VL_file_open(vol_cls, filename, flags, fapl_id, 
+                                        H5AC_ind_read_dxpl_id, NULL)))
+        HGOTO_ERROR(H5E_FILE, H5E_CANTOPENFILE, FAIL, "unable to open file")
+
+    /* setup VOL info struct */
+    if(NULL == (vol_info = H5FL_CALLOC(H5VL_t)))
+        HGOTO_ERROR(H5E_FILE, H5E_NOSPACE, FAIL, "can't allocate VL info struct")
+    vol_info->vol_cls = vol_cls;
+    vol_info->vol_id = plugin_prop.plugin_id;
+    if(H5I_inc_ref(vol_info->vol_id, FALSE) < 0)
+        HGOTO_ERROR(H5E_ATOM, H5E_CANTINC, FAIL, "unable to increment ref count on VOL plugin")
+
+    /* Get an atom for the file */
+    if((ret_value = H5VL_register_id(H5I_FILE, file, vol_info, TRUE)) < 0)
+        HGOTO_ERROR(H5E_ATOM, H5E_CANTREGISTER, FAIL, "unable to atomize file handle")
+
+done:
+    FUNC_LEAVE_API(ret_value)
+} /* end H5Fopen_ff() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:    H5Fclose_ff
+ *
+ * Purpose:     This function closes the file specified by FILE_ID,
+ *              terminating access to the file through FILE_ID.
+ *
+ * Return:      Success:        Non-negative
+ *              Failure:        Negative
+ *
+ * Programmer:  Neil Fortner
+ *              November 2016
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5Fclose_ff(hid_t file_id, hid_t H5_ATTR_UNUSED trans_id)
+{
+    herr_t   ret_value = SUCCEED;
+
+    FUNC_ENTER_API(FAIL)
+
+    /* flush file using trans_id? DSMINC */
+
+    /* Decrement reference count on atom.  When it reaches zero the file will be closed. */
+    if(H5I_dec_app_ref(file_id) < 0)
+        HGOTO_ERROR(H5E_ATOM, H5E_CANTCLOSEFILE, FAIL, "decrementing file ID failed")
+
+done:
+    FUNC_LEAVE_API(ret_value)
+} /* end H5Fclose_ff */
+
+
+/*-------------------------------------------------------------------------
  * Function:    H5Dcreate_ff
  *
  * Purpose:     Asynchronous wrapper around H5Dcreate().
@@ -127,8 +376,7 @@ H5FF__init_package(void)
  */
 hid_t
 H5Dcreate_ff(hid_t loc_id, const char *name, hid_t type_id, hid_t space_id, 
-             hid_t lcpl_id, hid_t dcpl_id, hid_t dapl_id, hid_t trans_id,
-             hid_t H5_ATTR_UNUSED estack_id)
+             hid_t lcpl_id, hid_t dcpl_id, hid_t dapl_id, hid_t trans_id)
 {
     void    *dset = NULL;       /* dset token from VOL plugin */
     H5VL_object_t *obj = NULL;        /* object token of loc_id */
@@ -138,8 +386,6 @@ H5Dcreate_ff(hid_t loc_id, const char *name, hid_t type_id, hid_t space_id,
     hid_t       ret_value;              /* Return value */
 
     FUNC_ENTER_API(FAIL)
-    H5TRACE9("i", "i*siiiiiii", loc_id, name, type_id, space_id, lcpl_id, dcpl_id,
-             dapl_id, trans_id, estack_id);
 
     if(!name || !*name)
         HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "no name")
@@ -224,7 +470,7 @@ done:
  *-------------------------------------------------------------------------
  */
 hid_t
-H5Dopen_ff(hid_t loc_id, const char *name, hid_t dapl_id, hid_t trans_id, hid_t H5_ATTR_UNUSED estack_id)
+H5Dopen_ff(hid_t loc_id, const char *name, hid_t dapl_id, hid_t trans_id)
 {
     void    *dset = NULL;       /* dset token from VOL plugin */
     H5VL_object_t *obj = NULL;        /* object token of loc_id */
@@ -234,7 +480,6 @@ H5Dopen_ff(hid_t loc_id, const char *name, hid_t dapl_id, hid_t trans_id, hid_t
     hid_t       ret_value;              /* Return value */
 
     FUNC_ENTER_API(FAIL)
-    H5TRACE5("i", "i*siii", loc_id, name, dapl_id, trans_id, estack_id);
 
     /* Check args */
     if(!name || !*name)
@@ -292,13 +537,12 @@ done:
  *-------------------------------------------------------------------------
  */
 herr_t
-H5Dclose_ff(hid_t dset_id, hid_t H5_ATTR_UNUSED estack_id)
+H5Dclose_ff(hid_t dset_id, hid_t H5_ATTR_UNUSED trans_id)
 {
     H5VL_object_t *dset;
     herr_t       ret_value = SUCCEED;   /* Return value */
 
     FUNC_ENTER_API(FAIL)
-    H5TRACE2("e", "ii", dset_id, estack_id);
 
     /* Check args */
     if(NULL == (dset = (H5VL_object_t *)H5I_object_verify(dset_id, H5I_DATASET)))
diff --git a/src/H5FFprivate.h b/src/H5FFprivate.h
index cfbb49e..7345b80 100755
--- a/src/H5FFprivate.h
+++ b/src/H5FFprivate.h
@@ -32,6 +32,10 @@
 /* DXPL property to store the transaction ID from the FF wrappers */
 #define H5VL_TRANS_ID        "transaction_id"
 
+/* property to tell the VOL plugin to acquire a transaction on the container
+ * when the file is created or opened */
+#define H5VL_ACQUIRE_TR_ID   "acquire_transaction"
+
 /****************************/
 /* Library Private Typedefs */
 /****************************/
diff --git a/src/H5FFpublic.h b/src/H5FFpublic.h
index b6585ae..4ccdb01 100644
--- a/src/H5FFpublic.h
+++ b/src/H5FFpublic.h
@@ -49,17 +49,17 @@ extern "C" {
 /*********************/
 
 /* API wrappers */
-/*H5_DLL hid_t H5Fcreate_ff(const char *filename, unsigned flags, hid_t fcpl,
-                          hid_t fapl, hid_t estack_id);
+H5_DLL hid_t H5Fcreate_ff(const char *filename, unsigned flags, hid_t fcpl_id,
+    hid_t fapl_id, hid_t *trans_id);
 H5_DLL hid_t H5Fopen_ff(const char *filename, unsigned flags, hid_t fapl_id,
-                        hid_t *rcxt_id, hid_t estack_id);
-H5_DLL herr_t H5Fclose_ff(hid_t file_id, hbool_t persist_flag, hid_t estack_id);*/
+    hid_t *trans_id);
+H5_DLL herr_t H5Fclose_ff(hid_t file_id, hid_t trans_id);
 H5_DLL hid_t H5Dcreate_ff(hid_t loc_id, const char *name, hid_t type_id,
-    hid_t space_id, hid_t lcpl_id, hid_t dcpl_id, hid_t dapl_id, hid_t trans_id,
-    hid_t estack_id);
+    hid_t space_id, hid_t lcpl_id, hid_t dcpl_id, hid_t dapl_id,
+    hid_t trans_id);
 H5_DLL hid_t H5Dopen_ff(hid_t loc_id, const char *name, hid_t dapl_id,
-    hid_t trans_id, hid_t estack_id);
-H5_DLL herr_t H5Dclose_ff(hid_t dset_id, hid_t estack_id);
+    hid_t trans_id);
+H5_DLL herr_t H5Dclose_ff(hid_t dset_id, hid_t trans_id);
 
 #endif /* H5_HAVE_EFF */
 
diff --git a/src/H5Pfapl.c b/src/H5Pfapl.c
index 61a63ea..e8bc054 100644
--- a/src/H5Pfapl.c
+++ b/src/H5Pfapl.c
@@ -40,6 +40,7 @@
 #include "H5Eprivate.h"		/* Error handling		  	*/
 #include "H5Fprivate.h"		/* Files		  	        */
 #include "H5FDprivate.h"	/* File drivers				*/
+#include "H5FFprivate.h"	/* FFwd wrappers		  	*/
 #include "H5VLprivate.h"	/* VOL plugins				*/
 #include "H5Iprivate.h"		/* IDs			  		*/
 #include "H5MMprivate.h"        /* Memory Management                    */
@@ -342,6 +343,7 @@ H5P__facc_reg_prop(H5P_genclass_t *pclass)
     const H5FD_driver_prop_t def_driver_prop = H5F_ACS_FILE_DRV_DEF;           /* Default VFL driver ID & info (initialized from a variable) */
     const H5VL_plugin_prop_t def_vol_prop = H5F_ACS_VOL_DEF;    /* Default VOL plugin ID & info (initialized from a variable) */
 
+    hid_t trans_id = FAIL;
     herr_t ret_value = SUCCEED;         /* Return value */
 
     FUNC_ENTER_STATIC
@@ -488,6 +490,11 @@ H5P__facc_reg_prop(H5P_genclass_t *pclass)
             NULL, NULL, NULL, NULL) < 0)
         HGOTO_ERROR(H5E_PLIST, H5E_CANTINSERT, FAIL, "can't insert property into class")
 
+    /* Register the transaction ID acquire property*/
+    if(H5P_register_real(pclass, H5VL_ACQUIRE_TR_ID, sizeof(hid_t), &trans_id, 
+                         NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTINSERT, FAIL, "can't insert property into class")
+
 #ifdef H5_HAVE_PARALLEL
     /* Register the metadata collective read flag */
     if(H5P_register_real(pclass, H5_COLL_MD_READ_FLAG_NAME, H5F_ACS_COLL_MD_READ_FLAG_SIZE, &H5F_def_coll_md_read_flag_g, 
diff --git a/src/H5TR.c b/src/H5TR.c
index cfee25f..51323cc 100644
--- a/src/H5TR.c
+++ b/src/H5TR.c
@@ -373,6 +373,8 @@ H5TR_close(H5TR_t *tr)
 
     FUNC_ENTER_NOAPI_NOINIT_NOERR
 
+    /*TODO: Keep track of lowest transaction number (LRE), slip daos epoch as it
+     * moves forward. */
     tr = H5FL_FREE(H5TR_t, tr);
 
     FUNC_LEAVE_NOAPI(SUCCEED)
diff --git a/src/H5VLdaosm.c b/src/H5VLdaosm.c
index c79d995..3495df5 100644
--- a/src/H5VLdaosm.c
+++ b/src/H5VLdaosm.c
@@ -507,10 +507,11 @@ H5VL_daosm_file_create(const char *name, unsigned flags, hid_t fcpl_id,
     H5P_genplist_t *plist = NULL;      /* Property list pointer */
     H5VL_daosm_file_t *file = NULL;
     daos_epoch_t epoch;
+    hid_t trans_id;
     daos_iov_t glob;
-    uint64_t gh_sizes[2];
+    uint64_t bcast_buf_64[6];
     char *gh_buf = NULL;
-    daos_obj_id_t oid = {0, 0, 0};
+    daos_obj_id_t gmd_oid = {0, 0, 0};
     hbool_t must_bcast = FALSE;
     int ret;
     void *ret_value = NULL;
@@ -552,6 +553,9 @@ H5VL_daosm_file_create(const char *name, unsigned flags, hid_t fcpl_id,
     /* Hash file name to create uuid */
     H5VL_daosm_hash128(name, &file->uuid);
 
+    /* Generate oid for global metadata object */
+    daos_obj_id_generate(&gmd_oid, DAOS_OC_REPLICA_RW);
+
     if(file->my_rank == 0) {
         daos_epoch_state_t epoch_state;
 
@@ -594,8 +598,7 @@ H5VL_daosm_file_create(const char *name, unsigned flags, hid_t fcpl_id,
             HGOTO_ERROR(H5E_FILE, H5E_CANTINIT, NULL, "can't hold epoch: %d", ret)
 
         /* Create global metadata object */
-        daos_obj_id_generate(&oid, DAOS_OC_REPLICA_RW);
-        if(0 != (ret = daos_obj_declare(file->coh, oid, 0, NULL /*oa*/, NULL /*event*/)))
+        if(0 != (ret = daos_obj_declare(file->coh, gmd_oid, 0, NULL /*oa*/, NULL /*event*/)))
             HGOTO_ERROR(H5E_FILE, H5E_CANTCREATE, NULL, "can't create global metadata object: %d", ret)
 
         /* Create root group */
@@ -608,7 +611,8 @@ H5VL_daosm_file_create(const char *name, unsigned flags, hid_t fcpl_id,
         if(0 != (ret = daos_obj_open(file->coh, file->root_grp->oid, epoch, DAOS_OO_RW, &file->root_grp->obj_oh, NULL /*event*/)))
             HGOTO_ERROR(H5E_FILE, H5E_CANTOPENOBJ, NULL, "can't open root group: %d", ret)
 
-        /* Write root group OID to global metadata object DSMINC */
+        /* Write root group OID, max oid per process to global metadata object
+         * DSMINC */
 
         /* Bcast global handles if there are other processes */
         if(file->num_procs > 1) {
@@ -618,25 +622,34 @@ H5VL_daosm_file_create(const char *name, unsigned flags, hid_t fcpl_id,
             glob.iov_len = 0;
             if(0 != (ret = daos_pool_local2global(file->poh, &glob)))
                 HGOTO_ERROR(H5E_FILE, H5E_CANTINIT, NULL, "can't get global pool handle size: %d", ret)
-            gh_sizes[0] = (uint64_t)glob.iov_buf_len;
+            bcast_buf_64[0] = (uint64_t)glob.iov_buf_len;
             glob.iov_buf = NULL;
             glob.iov_buf_len = 0;
             glob.iov_len = 0;
             if(0 != (ret = daos_cont_local2global(file->coh, &glob)))
                 HGOTO_ERROR(H5E_FILE, H5E_CANTINIT, NULL, "can't get global container handle size: %d", ret)
-            gh_sizes[1] = (uint64_t)glob.iov_buf_len;
+            bcast_buf_64[1] = (uint64_t)glob.iov_buf_len;
+
+            /* Add root group oid to bcast_buf_64 */
+            bcast_buf_64[2] = file->root_grp->oid.lo;
+            bcast_buf_64[3] = file->root_grp->oid.mid;
+            bcast_buf_64[4] = file->root_grp->oid.hi;
+
+            /* Add epoch to bcast_buf_64 */
+            HDassert(sizeof(bcast_buf_64[5]) == sizeof(epoch));
+            bcast_buf_64[5] = (uint64_t)epoch;
 
             /* Retrieve global pool and container handles */
-            if(NULL == (gh_buf = (char *)H5MM_malloc(gh_sizes[0] + gh_sizes[1])))
+            if(NULL == (gh_buf = (char *)H5MM_malloc(bcast_buf_64[0] + bcast_buf_64[1])))
                 HGOTO_ERROR(H5E_FILE, H5E_CANTALLOC, NULL, "can't allocate space for global handles")
             glob.iov_buf = gh_buf;
-            glob.iov_buf_len = gh_sizes[0];
+            glob.iov_buf_len = bcast_buf_64[0];
             glob.iov_len = 0;
             if(0 != (ret = daos_pool_local2global(file->poh, &glob)))
                 HGOTO_ERROR(H5E_FILE, H5E_CANTINIT, NULL, "can't get global pool handle: %d", ret)
             HDassert(glob.iov_len == glob.iov_buf_len);
-            glob.iov_buf = gh_buf + gh_sizes[0];
-            glob.iov_buf_len = gh_sizes[1];
+            glob.iov_buf = gh_buf + bcast_buf_64[0];
+            glob.iov_buf_len = bcast_buf_64[1];
             glob.iov_len = 0;
             if(0 != (ret = daos_cont_local2global(file->coh, &glob)))
                 HGOTO_ERROR(H5E_FILE, H5E_CANTINIT, NULL, "can't get global container handle: %d", ret)
@@ -645,58 +658,64 @@ H5VL_daosm_file_create(const char *name, unsigned flags, hid_t fcpl_id,
             /* We are about to bcast so we no longer need to bcast on failure */
             must_bcast = FALSE;
 
-            /* MPI_Bcast gh_sizes */
-            if(MPI_SUCCESS != MPI_Bcast(gh_sizes, 2, MPI_UINT64_T, 0, fa->comm))
+            /* MPI_Bcast bcast_buf_64 */
+            if(MPI_SUCCESS != MPI_Bcast(bcast_buf_64, sizeof(bcast_buf_64)/sizeof(bcast_buf_64[0]), MPI_UINT64_T, 0, fa->comm))
                 HGOTO_ERROR(H5E_FILE, H5E_MPI, NULL, "can't bcast global handle sizes")
 
             /* MPI_Bcast gh_buf */
-            if(MPI_SUCCESS != MPI_Bcast(gh_buf, (int)(gh_sizes[0] + gh_sizes[1]), MPI_BYTE, 0, fa->comm))
+            if(MPI_SUCCESS != MPI_Bcast(gh_buf, (int)(bcast_buf_64[0] + bcast_buf_64[1]), MPI_BYTE, 0, fa->comm))
                 HGOTO_ERROR(H5E_FILE, H5E_MPI, NULL, "can't bcast global handle sizes")
         } /* end if */
-
-        /* Commit epoch DSMINC */
-        if(0 != (ret = daos_epoch_commit(file->coh, epoch, NULL /*state*/, NULL /*event*/)))
-            HGOTO_ERROR(H5E_FILE, H5E_WRITEERROR, NULL, "can't commit epoch: %d", ret)
-        epoch++;
     } /* end if */
     else {
-        /* Receive gh_sizes */
-        if(MPI_SUCCESS != MPI_Bcast(gh_sizes, 2, MPI_UINT64_T, 0, fa->comm))
+        /* Receive bcast_buf_64 */
+        if(MPI_SUCCESS != MPI_Bcast(bcast_buf_64, sizeof(bcast_buf_64)/sizeof(bcast_buf_64[0]), MPI_UINT64_T, 0, fa->comm))
             HGOTO_ERROR(H5E_FILE, H5E_MPI, NULL, "can't bcast global handle sizes")
 
-        /* Check for gh_sizes set to 0 - indicates failure */
-        if(gh_sizes[0] == 0) {
-            HDassert(gh_sizes[1] == 0);
+        /* Check for bcast_buf_64[0] set to 0 - indicates failure */
+        if(bcast_buf_64[0] == 0) {
+            HDassert(bcast_buf_64[1] == 0);
             HGOTO_ERROR(H5E_FILE, H5E_CANTOPENFILE, NULL, "lead process failed to open file")
         } /* end if */
 
+        /* Retrieve root group oid from bcast_buf_64 */
+        file->root_grp->oid.lo = bcast_buf_64[2];
+        file->root_grp->oid.mid = bcast_buf_64[3];
+        file->root_grp->oid.hi = bcast_buf_64[4];
+
+        /* Retrieve epoch from bcast_buf_64 */
+        HDassert(sizeof(bcast_buf_64[5]) == sizeof(epoch));
+        epoch = (daos_epoch_t)bcast_buf_64[5];
+
         /* Allocate global handle buffer */
-        if(NULL == (gh_buf = (char *)H5MM_malloc(gh_sizes[0] + gh_sizes[1])))
+        if(NULL == (gh_buf = (char *)H5MM_malloc(bcast_buf_64[0] + bcast_buf_64[1])))
             HGOTO_ERROR(H5E_FILE, H5E_CANTALLOC, NULL, "can't allocate space for global handles")
 
         /* Receive gh_buf */
-        if(MPI_SUCCESS != MPI_Bcast(gh_buf, (int)(gh_sizes[0] + gh_sizes[1]), MPI_BYTE, 0, fa->comm))
+        if(MPI_SUCCESS != MPI_Bcast(gh_buf, (int)(bcast_buf_64[0] + bcast_buf_64[1]), MPI_BYTE, 0, fa->comm))
             HGOTO_ERROR(H5E_FILE, H5E_MPI, NULL, "can't bcast global handle sizes")
 
         /* Create local pool and container handles */
         glob.iov_buf = gh_buf;
-        glob.iov_buf_len = gh_sizes[0];
-        glob.iov_len = gh_sizes[0];
+        glob.iov_buf_len = bcast_buf_64[0];
+        glob.iov_len = bcast_buf_64[0];
         if(0 != (ret = daos_pool_global2local(glob, &file->poh)))
             HGOTO_ERROR(H5E_FILE, H5E_CANTOPENOBJ, NULL, "can't get local pool handle: %d", ret)
-        glob.iov_buf = gh_buf + gh_sizes[0];
-        glob.iov_buf_len = gh_sizes[1];
-        glob.iov_len = gh_sizes[1];
+        glob.iov_buf = gh_buf + bcast_buf_64[0];
+        glob.iov_buf_len = bcast_buf_64[1];
+        glob.iov_len = bcast_buf_64[1];
         if(0 != (ret = daos_cont_global2local(file->poh, glob, &file->coh)))
             HGOTO_ERROR(H5E_FILE, H5E_CANTOPENOBJ, NULL, "can't get local container handle: %d", ret)
 
-        /* Leave root group handle empty for now */
+        /* Open root group */
+        if(0 != (ret = daos_obj_open(file->coh, file->root_grp->oid, epoch, DAOS_OO_RW, &file->root_grp->obj_oh, NULL /*event*/)))
+            HGOTO_ERROR(H5E_FILE, H5E_CANTOPENOBJ, NULL, "can't open root group: %d", ret)
 
         /* Handle pool_info and container_info DSMINC */
     } /* end else */
 
     /* Open global metadata object */
-    if(0 != (ret = daos_obj_open(file->glob_md_oh, oid, 0, DAOS_OO_RW, &file->glob_md_oh, NULL /*event*/)))
+    if(0 != (ret = daos_obj_open(file->glob_md_oh, gmd_oid, 0, DAOS_OO_RW, &file->glob_md_oh, NULL /*event*/)))
         HGOTO_ERROR(H5E_FILE, H5E_CANTOPENFILE, NULL, "can't open global metadata object: %d", ret)
 
     /* Finish setting up file struct */
@@ -718,6 +737,29 @@ H5VL_daosm_file_create(const char *name, unsigned flags, hid_t fcpl_id,
     if(FAIL == H5FD_mpi_comm_info_dup(fa->comm, fa->info, &file->comm, &file->info))
         HGOTO_ERROR(H5E_INTERNAL, H5E_CANTCOPY, NULL, "Communicator/Info duplicate failed");
 
+    /* Determine if we want to acquire a transaction for the file creation */
+    if(H5P_get(plist, H5VL_ACQUIRE_TR_ID, &trans_id) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, NULL, "can't get property value for trans id");
+
+    if(FAIL == trans_id) {
+        if(file->my_rank == 0)
+            /* Transaction not requested, commit the epoch */
+            if(0 != (ret = daos_epoch_commit(file->coh, epoch, NULL /*state*/, NULL /*event*/)))
+                HGOTO_ERROR(H5E_FILE, H5E_WRITEERROR, NULL, "can't commit epoch: %d", ret)
+    } /* end if */
+    else {
+        /* Transaction requested, do not commit the epoch - it is up to the
+         * application */
+        H5TR_t *tr = NULL;
+
+        /* get the TR object */
+        if(NULL == (tr = (H5TR_t *)H5I_object_verify(trans_id, H5I_TR)))
+            HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, NULL, "not a TRANSACTION ID");
+
+        tr->epoch = epoch;
+        tr->file = file;
+    } /* end else */
+
     ret_value = (void *)file;
 
 done:
@@ -727,12 +769,11 @@ done:
     /* If the operation is synchronous and it failed at the server, or it failed
      * locally, then cleanup and return fail */
     if(NULL == ret_value) {
-        /* Bcast gh_sizes as '0' if necessary - this will trigger failures in
-         * the other processes so we do not need to do the second bcast. */
+        /* Bcast bcast_buf_64 as '0' if necessary - this will trigger failures
+         * in the other processes so we do not need to do the second bcast. */
         if(must_bcast) {
-            gh_sizes[0] = 0;
-            gh_sizes[1] = 0;
-            if(MPI_SUCCESS != MPI_Bcast(gh_sizes, 2, MPI_UINT64_T, 0, fa->comm))
+            HDmemset(bcast_buf_64, 0, sizeof(bcast_buf_64));
+            if(MPI_SUCCESS != MPI_Bcast(bcast_buf_64, sizeof(bcast_buf_64)/sizeof(bcast_buf_64[0]), MPI_UINT64_T, 0, fa->comm))
                 HDONE_ERROR(H5E_FILE, H5E_MPI, NULL, "can't bcast global handle sizes")
         } /* end if */
 
@@ -766,10 +807,11 @@ H5VL_daosm_file_open(const char *name, unsigned flags, hid_t fapl_id,
     H5P_genplist_t *plist = NULL;      /* Property list pointer */
     H5VL_daosm_file_t *file = NULL;
     daos_epoch_t epoch;
+    hid_t trans_id;
     daos_iov_t glob;
-    uint64_t gh_sizes[2];
+    uint64_t bcast_buf_64[6];
     char *gh_buf = NULL;
-    daos_obj_id_t oid = {0, 0, 0};
+    daos_obj_id_t gmd_oid = {0, 0, 0};
     hbool_t must_bcast = FALSE;
     int ret;
     void *ret_value = NULL;
@@ -802,6 +844,9 @@ H5VL_daosm_file_open(const char *name, unsigned flags, hid_t fapl_id,
     /* Hash file name to create uuid */
     H5VL_daosm_hash128(name, &file->uuid);
 
+    /* Generate oid for global metadata object */
+    daos_obj_id_generate(&gmd_oid, DAOS_OC_REPLICA_RW);
+
     if(file->my_rank == 0) {
         daos_epoch_state_t epoch_state;
 
@@ -827,6 +872,9 @@ H5VL_daosm_file_open(const char *name, unsigned flags, hid_t fapl_id,
         if(0 != (ret = daos_epoch_hold(file->coh, &epoch, NULL /*state*/, NULL /*event*/)))
             HGOTO_ERROR(H5E_FILE, H5E_CANTINIT, NULL, "can't hold epoch: %d", ret)
 
+        /* Read from the HCE */
+        epoch--;
+
         /* Open root group */
         /* Read root group OID from global metadata object DSMINC */
         file->root_grp->oid.lo = 1;
@@ -842,25 +890,34 @@ H5VL_daosm_file_open(const char *name, unsigned flags, hid_t fapl_id,
             glob.iov_len = 0;
             if(0 != (ret = daos_pool_local2global(file->poh, &glob)))
                 HGOTO_ERROR(H5E_FILE, H5E_CANTINIT, NULL, "can't get global pool handle size: %d", ret)
-            gh_sizes[0] = (uint64_t)glob.iov_buf_len;
+            bcast_buf_64[0] = (uint64_t)glob.iov_buf_len;
             glob.iov_buf = NULL;
             glob.iov_buf_len = 0;
             glob.iov_len = 0;
             if(0 != (ret = daos_cont_local2global(file->coh, &glob)))
                 HGOTO_ERROR(H5E_FILE, H5E_CANTINIT, NULL, "can't get global container handle size: %d", ret)
-            gh_sizes[1] = (uint64_t)glob.iov_buf_len;
+            bcast_buf_64[1] = (uint64_t)glob.iov_buf_len;
+
+            /* Add root group oid to bcast_buf_64 */
+            bcast_buf_64[2] = file->root_grp->oid.lo;
+            bcast_buf_64[3] = file->root_grp->oid.mid;
+            bcast_buf_64[4] = file->root_grp->oid.hi;
+
+            /* Add epoch to bcast_buf_64 */
+            HDassert(sizeof(bcast_buf_64[5]) == sizeof(epoch));
+            bcast_buf_64[5] = (uint64_t)epoch;
 
             /* Retrieve global pool and container handles */
-            if(NULL == (gh_buf = (char *)malloc(gh_sizes[0] + gh_sizes[1])))
-                HGOTO_ERROR(H5E_FILE, H5E_CANTALLOC, NULL, "can't allocate space for global handles")
+            if(NULL == (gh_buf = (char *)malloc(bcast_buf_64[0] + bcast_buf_64[1])))
+                HGOTO_ERROR(H5E_FILE, H5E_CANTALLOC, bcast_buf_64, "can't allocate space for global handles")
             glob.iov_buf = gh_buf;
-            glob.iov_buf_len = gh_sizes[0];
+            glob.iov_buf_len = bcast_buf_64[0];
             glob.iov_len = 0;
             if(0 != (ret = daos_pool_local2global(file->poh, &glob)))
                 HGOTO_ERROR(H5E_FILE, H5E_CANTINIT, NULL, "can't get global pool handle: %d", ret)
             HDassert(glob.iov_len == glob.iov_buf_len);
-            glob.iov_buf = gh_buf + gh_sizes[0];
-            glob.iov_buf_len = gh_sizes[1];
+            glob.iov_buf = gh_buf + bcast_buf_64[0];
+            glob.iov_buf_len = bcast_buf_64[1];
             glob.iov_len = 0;
             if(0 != (ret = daos_cont_local2global(file->coh, &glob)))
                 HGOTO_ERROR(H5E_FILE, H5E_CANTINIT, NULL, "can't get global container handle: %d", ret)
@@ -869,54 +926,64 @@ H5VL_daosm_file_open(const char *name, unsigned flags, hid_t fapl_id,
             /* We are about to bcast so we no longer need to bcast on failure */
             must_bcast = FALSE;
 
-            /* MPI_Bcast gh_sizes */
-            if(MPI_SUCCESS != MPI_Bcast(gh_sizes, 2, MPI_UINT64_T, 0, fa->comm))
+            /* MPI_Bcast bcast_buf_64 */
+            if(MPI_SUCCESS != MPI_Bcast(bcast_buf_64, sizeof(bcast_buf_64)/sizeof(bcast_buf_64[0]), MPI_UINT64_T, 0, fa->comm))
                 HGOTO_ERROR(H5E_FILE, H5E_MPI, NULL, "can't bcast global handle sizes")
 
             /* MPI_Bcast gh_buf */
-            if(MPI_SUCCESS != MPI_Bcast(gh_buf, (int)(gh_sizes[0] + gh_sizes[1]), MPI_BYTE, 0, fa->comm))
-                HGOTO_ERROR(H5E_FILE, H5E_MPI, NULL, "can't bcast global handle sizes")
+            if(MPI_SUCCESS != MPI_Bcast(gh_buf, (int)(bcast_buf_64[0] + bcast_buf_64[1]), MPI_BYTE, 0, fa->comm))
+                HGOTO_ERROR(H5E_FILE, H5E_MPI, NULL, "can't bcast global handles")
         } /* end if */
     } /* end if */
     else {
-        /* Receive gh_sizes */
-        if(MPI_SUCCESS != MPI_Bcast(gh_sizes, 2, MPI_UINT64_T, 0, fa->comm))
+        /* Receive bcast_buf_64 */
+        if(MPI_SUCCESS != MPI_Bcast(bcast_buf_64, sizeof(bcast_buf_64)/sizeof(bcast_buf_64[0]), MPI_UINT64_T, 0, fa->comm))
             HGOTO_ERROR(H5E_FILE, H5E_MPI, NULL, "can't bcast global handle sizes")
 
-        /* Check for gh_sizes set to 0 - indicates failure */
-        if(gh_sizes[0] == 0) {
-            HDassert(gh_sizes[1] == 0);
+        /* Check for bcast_buf_64[0] set to 0 - indicates failure */
+        if(bcast_buf_64[0] == 0) {
+            HDassert(bcast_buf_64[1] == 0);
             HGOTO_ERROR(H5E_FILE, H5E_CANTOPENFILE, NULL, "lead process failed to open file")
         } /* end if */
 
+        /* Retrieve root group oid from bcast_buf_64 */
+        file->root_grp->oid.lo = bcast_buf_64[2];
+        file->root_grp->oid.mid = bcast_buf_64[3];
+        file->root_grp->oid.hi = bcast_buf_64[4];
+
+        /* Retrieve epoch from bcast_buf_64 */
+        HDassert(sizeof(bcast_buf_64[5]) == sizeof(epoch));
+        epoch = (daos_epoch_t)bcast_buf_64[5];
+
         /* Allocate global handle buffer */
-        if(NULL == (gh_buf = (char *)malloc(gh_sizes[0] + gh_sizes[1])))
+        if(NULL == (gh_buf = (char *)malloc(bcast_buf_64[0] + bcast_buf_64[1])))
             HGOTO_ERROR(H5E_FILE, H5E_CANTALLOC, NULL, "can't allocate space for global handles")
 
         /* Receive gh_buf */
-        if(MPI_SUCCESS != MPI_Bcast(gh_buf, (int)(gh_sizes[0] + gh_sizes[1]), MPI_BYTE, 0, fa->comm))
-            HGOTO_ERROR(H5E_FILE, H5E_MPI, NULL, "can't bcast global handle sizes")
+        if(MPI_SUCCESS != MPI_Bcast(gh_buf, (int)(bcast_buf_64[0] + bcast_buf_64[1]), MPI_BYTE, 0, fa->comm))
+            HGOTO_ERROR(H5E_FILE, H5E_MPI, NULL, "can't bcast global handles")
 
         /* Create local pool and container handles */
         glob.iov_buf = gh_buf;
-        glob.iov_buf_len = gh_sizes[0];
-        glob.iov_len = gh_sizes[0];
+        glob.iov_buf_len = bcast_buf_64[0];
+        glob.iov_len = bcast_buf_64[0];
         if(0 != (ret = daos_pool_global2local(glob, &file->poh)))
             HGOTO_ERROR(H5E_FILE, H5E_CANTOPENOBJ, NULL, "can't get local pool handle: %d", ret)
-        glob.iov_buf = gh_buf + gh_sizes[0];
-        glob.iov_buf_len = gh_sizes[1];
-        glob.iov_len = gh_sizes[1];
+        glob.iov_buf = gh_buf + bcast_buf_64[0];
+        glob.iov_buf_len = bcast_buf_64[1];
+        glob.iov_len = bcast_buf_64[1];
         if(0 != (ret = daos_cont_global2local(file->poh, glob, &file->coh)))
             HGOTO_ERROR(H5E_FILE, H5E_CANTOPENOBJ, NULL, "can't get local container handle: %d", ret)
 
-        /* Leave root group handle empty for now */
+        /* Open root group */
+        if(0 != (ret = daos_obj_open(file->coh, file->root_grp->oid, epoch, DAOS_OO_RW, &file->root_grp->obj_oh, NULL /*event*/)))
+            HGOTO_ERROR(H5E_FILE, H5E_CANTOPENOBJ, NULL, "can't open root group: %d", ret)
 
         /* Handle pool_info and container_info DSMINC */
     } /* end else */
 
     /* Open global metadata object */
-    daos_obj_id_generate(&oid, DAOS_OC_REPLICA_RW);
-    if(0 != (ret = daos_obj_open(file->glob_md_oh, oid, 0, DAOS_OO_RW, &file->glob_md_oh, NULL /*event*/)))
+    if(0 != (ret = daos_obj_open(file->glob_md_oh, gmd_oid, 0, DAOS_OO_RW, &file->glob_md_oh, NULL /*event*/)))
         HGOTO_ERROR(H5E_FILE, H5E_CANTOPENFILE, NULL, "can't open global metadata object: %d", ret)
 
     /* Finish setting up file struct */
@@ -937,6 +1004,22 @@ H5VL_daosm_file_open(const char *name, unsigned flags, hid_t fapl_id,
     if(FAIL == H5FD_mpi_comm_info_dup(fa->comm, fa->info, &file->comm, &file->info))
         HGOTO_ERROR(H5E_INTERNAL, H5E_CANTCOPY, NULL, "Communicator/Info duplicate failed");
 
+    /* Determine if we want to acquire a transaction for the opened file */
+    if(H5P_get(plist, H5VL_ACQUIRE_TR_ID, &trans_id) < 0)
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, NULL, "can't get property value for trans id");
+
+    if(FAIL != trans_id) {
+        /* Transaction requested */
+        H5TR_t *tr = NULL;
+
+        /* get the TR object */
+        if(NULL == (tr = (H5TR_t *)H5I_object_verify(trans_id, H5I_TR)))
+            HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, NULL, "not a TRANSACTION ID");
+
+        tr->epoch = epoch;
+        tr->file = file;
+    } /* end else */
+
     ret_value = (void *)file;
 
 done:
@@ -946,12 +1029,11 @@ done:
     /* If the operation is synchronous and it failed at the server, or it failed
      * locally, then cleanup and return fail */
     if(NULL == ret_value) {
-        /* Bcast gh_sizes as '0' if necessary - this will trigger failures in
-         * the other processes so we do not need to do the second bcast. */
+        /* Bcast bcast_buf_64 as '0' if necessary - this will trigger failures
+         * in the other processes so we do not need to do the second bcast. */
         if(must_bcast) {
-            gh_sizes[0] = 0;
-            gh_sizes[1] = 0;
-            if(MPI_SUCCESS != MPI_Bcast(gh_sizes, 2, MPI_UINT64_T, 0, fa->comm))
+            HDmemset(bcast_buf_64, 0, sizeof(bcast_buf_64));
+            if(MPI_SUCCESS != MPI_Bcast(bcast_buf_64, sizeof(bcast_buf_64)/sizeof(bcast_buf_64[0]), MPI_UINT64_T, 0, fa->comm))
                 HDONE_ERROR(H5E_FILE, H5E_MPI, NULL, "can't bcast global handle sizes")
         } /* end if */