Merge pull request #1955 in HDFFV/hdf5 from ~DEROBINS/hdf5_der:missing_vol_markup to develop

* commit '4fb64c89fe52a309150ca2d5bb97eb4763e598e9':
  Converted H5O MD cache cork calls to use the VOL.
  Marked up H5Fget/set_mpi_atomicity() to use the VOL.

11 files changed, 372 insertions, 95 deletions

diff --git a/src/H5Fmpi.c b/src/H5Fmpi.c
index bb422ac..1630d6b 100644
--- a/src/H5Fmpi.c
+++ b/src/H5Fmpi.c
@@ -38,6 +38,8 @@
 #include "H5FDprivate.h"	/* File drivers				*/
 #include "H5Iprivate.h"		/* IDs			  		*/
 
+#include "H5VLnative_private.h" /* Native VOL connector                     */
+
 
 /****************/
 /* Local Macros */
@@ -234,12 +236,43 @@ done:
 
 
 /*-------------------------------------------------------------------------
+ * Function:    H5F_set_mpi_atomicity
+ *
+ * Purpose:     Private call to set the atomicity mode
+ *
+ * Return:      SUCCEED/FAIL
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5F_set_mpi_atomicity(H5F_t *file, hbool_t flag)
+{
+    herr_t       ret_value = SUCCEED;
+
+    FUNC_ENTER_NOAPI(FAIL);
+
+    /* Check args */
+    HDassert(file);
+
+    /* Check VFD */
+    if (!H5F_HAS_FEATURE(file, H5FD_FEAT_HAS_MPI))
+        HGOTO_ERROR(H5E_FILE, H5E_BADVALUE, FAIL, "incorrect VFL driver, does not support MPI atomicity mode");
+
+    /* Set atomicity value */
+    if (H5FD_set_mpio_atomicity(file->shared->lf, flag) < 0)
+        HGOTO_ERROR(H5E_FILE, H5E_CANTSET, FAIL, "can't set atomicity flag");
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value);
+} /* end H5F_set_mpi_atomicity() */
+
+
+/*-------------------------------------------------------------------------
  * Function:    H5Fset_mpi_atomicity
  *
  * Purpose:     Sets the atomicity mode
  *
  * Return:      Success:    Non-negative
- *
  *              Failure:    Negative
  *
  * Programmer:  Mohamad Chaarawi
@@ -250,27 +283,57 @@ done:
 herr_t
 H5Fset_mpi_atomicity(hid_t file_id, hbool_t flag)
 {
-    H5F_t       *file;
-    herr_t       ret_value = SUCCEED;
+    H5VL_object_t   *vol_obj = NULL;
+    int va_flag = (int)flag;    /* C is grumpy about passing hbool_t via va_arg */
+    herr_t          ret_value = SUCCEED;
 
-    FUNC_ENTER_API(FAIL)
+    FUNC_ENTER_API(FAIL);
     H5TRACE2("e", "ib", file_id, flag);
 
+    /* Get the file object */
+    if (NULL == (vol_obj = (H5VL_object_t *)H5I_object_verify(file_id, H5I_FILE)))
+        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "invalid file identifier");
+
+    /* Set atomicity value */
+    if (H5VL_file_optional(vol_obj, H5P_DATASET_XFER_DEFAULT, H5_REQUEST_NULL, H5VL_NATIVE_FILE_SET_MPI_ATOMICITY, va_flag) < 0)
+        HGOTO_ERROR(H5E_FILE, H5E_CANTSET, FAIL, "unable to set MPI atomicity");
+
+done:
+    FUNC_LEAVE_API(ret_value);
+} /* end H5Fset_mpi_atomicity() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:    H5F_get_mpi_atomicity
+ *
+ * Purpose:     Private call to get the atomicity mode
+ *
+ * Return:      SUCCEED/FAIL
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5F_get_mpi_atomicity(H5F_t *file, hbool_t *flag)
+{
+    herr_t     ret_value = SUCCEED;
+
+    FUNC_ENTER_NOAPI(FAIL);
+
     /* Check args */
-    if(NULL == (file = (H5F_t *)H5VL_object_verify(file_id, H5I_FILE)))
-        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "not a file ID")
+    HDassert(file);
+    HDassert(flag);
 
     /* Check VFD */
-    if(!H5F_HAS_FEATURE(file, H5FD_FEAT_HAS_MPI))
-        HGOTO_ERROR(H5E_FILE, H5E_BADVALUE, FAIL, "incorrect VFL driver, does not support MPI atomicity mode")
+    if (!H5F_HAS_FEATURE(file, H5FD_FEAT_HAS_MPI))
+        HGOTO_ERROR(H5E_FILE, H5E_BADVALUE, FAIL, "incorrect VFL driver, does not support MPI atomicity mode");
 
-    /* set atomicity value */
-    if (H5FD_set_mpio_atomicity (file->shared->lf, flag) < 0)
-        HGOTO_ERROR(H5E_FILE, H5E_CANTSET, FAIL, "can't set atomicity flag")
+    /* Get atomicity value */
+    if (H5FD_get_mpio_atomicity(file->shared->lf, flag) < 0)
+        HGOTO_ERROR(H5E_FILE, H5E_CANTGET, FAIL, "can't get atomicity flag");
 
 done:
-    FUNC_LEAVE_API(ret_value)
-}
+    FUNC_LEAVE_NOAPI(ret_value);
+} /* end H5F_get_mpi_atomicity() */
 
 
 /*-------------------------------------------------------------------------
@@ -279,7 +342,6 @@ done:
  * Purpose:     Returns the atomicity mode
  *
  * Return:      Success:    Non-negative
- *
  *              Failure:    Negative
  *
  * Programmer:  Mohamad Chaarawi
@@ -290,27 +352,23 @@ done:
 herr_t
 H5Fget_mpi_atomicity(hid_t file_id, hbool_t *flag)
 {
-    H5F_t      *file;
-    herr_t     ret_value = SUCCEED;
+    H5VL_object_t   *vol_obj = NULL;
+    herr_t          ret_value = SUCCEED;
 
-    FUNC_ENTER_API(FAIL)
+    FUNC_ENTER_API(FAIL);
     H5TRACE2("e", "i*b", file_id, flag);
 
-    /* Check args */
-    if(NULL == (file = (H5F_t *)H5VL_object_verify(file_id, H5I_FILE)))
-        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "not a file ID")
-
-    /* Check VFD */
-    if(!H5F_HAS_FEATURE(file, H5FD_FEAT_HAS_MPI))
-        HGOTO_ERROR(H5E_FILE, H5E_BADVALUE, FAIL, "incorrect VFL driver, does not support MPI atomicity mode")
+    /* Get the file object */
+    if (NULL == (vol_obj = (H5VL_object_t *)H5I_object_verify(file_id, H5I_FILE)))
+        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "invalid file identifier");
 
-    /* get atomicity value */
-    if (H5FD_get_mpio_atomicity (file->shared->lf, flag) < 0)
-        HGOTO_ERROR(H5E_FILE, H5E_CANTGET, FAIL, "can't get atomicity flag")
+    /* Get atomicity value */
+    if (H5VL_file_optional(vol_obj, H5P_DATASET_XFER_DEFAULT, H5_REQUEST_NULL, H5VL_NATIVE_FILE_GET_MPI_ATOMICITY, flag) < 0)
+        HGOTO_ERROR(H5E_FILE, H5E_CANTGET, FAIL, "unable to get MPI atomicity");
 
 done:
-    FUNC_LEAVE_API(ret_value)
-}
+    FUNC_LEAVE_API(ret_value);
+} /* end H5Fget_mpi_atomicity() */
 
 
 /*-------------------------------------------------------------------------
diff --git a/src/H5Fprivate.h b/src/H5Fprivate.h
index 8c70663..7e87f79 100644
--- a/src/H5Fprivate.h
+++ b/src/H5Fprivate.h
@@ -855,6 +855,8 @@ H5_DLL int H5F_shared_mpi_get_size(const H5F_shared_t *f_sh);
 H5_DLL int H5F_mpi_get_size(const H5F_t *f);
 H5_DLL herr_t H5F_mpi_retrieve_comm(hid_t loc_id, hid_t acspl_id, MPI_Comm *mpi_comm);
 H5_DLL herr_t H5F_get_mpi_info(const H5F_t *f, MPI_Info **f_info);
+H5_DLL herr_t H5F_get_mpi_atomicity(H5F_t *file, hbool_t *flag);
+H5_DLL herr_t H5F_set_mpi_atomicity(H5F_t *file, hbool_t flag);
 #endif /* H5_HAVE_PARALLEL */
 
 /* External file cache routines */
diff --git a/src/H5I.c b/src/H5I.c
index ab68e38..201ad9a 100644
--- a/src/H5I.c
+++ b/src/H5I.c
@@ -1086,6 +1086,56 @@ done:
 
 
 /*-------------------------------------------------------------------------
+ * Function:    H5I_is_file_object
+ *
+ * Purpose:     Convenience function to determine if an ID represents
+ *              a file object.
+ *
+ *              In H5O calls, you can't use object_verify to ensure
+ *              the ID was of the correct class since there's no
+ *              H5I_OBJECT ID class.
+ *
+ * Return:      Success:    TRUE/FALSE
+ *              Failure:    FAIL
+ *
+ *-------------------------------------------------------------------------
+ */
+htri_t
+H5I_is_file_object(hid_t id)
+{
+    H5I_type_t  id_type     = H5I_get_type(id);
+    htri_t      ret_value   = FAIL;
+
+    FUNC_ENTER_NOAPI(FAIL);
+
+    /* Fail if the ID type is out of range */
+    HDassert(id_type >= 1 && id_type < H5I_NTYPES);
+
+    /* Return TRUE if the ID is a file object (dataset, group, map, or committed
+     * datatype), FALSE otherwise.
+     */
+    if (H5I_DATASET == id_type || H5I_GROUP == id_type || H5I_MAP == id_type) {
+        ret_value = TRUE;
+    }
+    else if (H5I_DATATYPE == id_type) {
+
+        H5T_t *dt = NULL;
+
+        if(NULL == (dt = (H5T_t *)H5I_object(id)))
+            HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "unable to get underlying datatype struct")
+
+        ret_value = H5T_is_named(dt);
+    }
+    else {
+        ret_value = FALSE;
+    }
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* H5I_is_file_object() */
+
+
+/*-------------------------------------------------------------------------
  * Function:    H5Iremove_verify
  *
  * Purpose:     Removes the specified ID from its type, first checking that the
diff --git a/src/H5Iprivate.h b/src/H5Iprivate.h
index 9068b5f..cc1ce1f 100644
--- a/src/H5Iprivate.h
+++ b/src/H5Iprivate.h
@@ -92,6 +92,7 @@ H5_DLL void *H5I_object(hid_t id);
 H5_DLL void *H5I_object_verify(hid_t id, H5I_type_t id_type);
 H5_DLL void *H5I_remove(hid_t id);
 H5_DLL void *H5I_subst(hid_t id, const void *new_object);
+H5_DLL htri_t H5I_is_file_object(hid_t id);
 
 /* ID registration functions */
 H5_DLL hid_t H5I_register(H5I_type_t type, const void *object, hbool_t app_ref);
diff --git a/src/H5O.c b/src/H5O.c
index bf2d799..ed68ed0 100644
--- a/src/H5O.c
+++ b/src/H5O.c
@@ -1116,113 +1116,215 @@ done:
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5Odisable_mdc_flushes
+ * Function:    H5O_disable_mdc_flushes
  *
- * Purpose:	To "cork" an object:
- *		--keep dirty entries associated with the object in the metadata cache
+ * Purpose:     Private version of the metadata cache cork function.
  *
- * Return:	Success:	Non-negative
- *		Failure:	Negative
+ * Return:      SUCCEED/FAIL
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5O_disable_mdc_flushes(H5O_loc_t *oloc)
+{
+    herr_t      ret_value = SUCCEED;
+
+    FUNC_ENTER_NOAPI(FAIL);
+
+    if (H5AC_cork(oloc->file, oloc->addr, H5AC__SET_CORK, NULL) < 0)
+        HGOTO_ERROR(H5E_OHDR, H5E_CANTCORK, FAIL, "unable to cork object");
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value);
+} /* H5O_disable_mdc_flushes() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:    H5Odisable_mdc_flushes
+ *
+ * Purpose:     "Cork" an object, keeping dirty entries associated with the
+ *              object in the metadata cache.
+ *
+ * Return:      Success:    Non-negative
+ *              Failure:    Negative
  *
- * Programmer:	Vailin Choi
- *		January 2014
+ * Programmer:  Vailin Choi
+ *              January 2014
  *
  *-------------------------------------------------------------------------
  */
 herr_t
 H5Odisable_mdc_flushes(hid_t object_id)
 {
-    H5O_loc_t  *oloc;			/* Object location */
-    herr_t      ret_value = SUCCEED;	/* Return value */
+    H5VL_object_t       *vol_obj;               /* Object token of loc_id */
+    H5VL_loc_params_t   loc_params;             /* Location parameters */
+    herr_t              ret_value = SUCCEED;    /* Return value */
 
-    FUNC_ENTER_API(FAIL)
+    FUNC_ENTER_API(FAIL);
     H5TRACE1("e", "i", object_id);
 
-    /* Get the object's oloc */
-    if(NULL == (oloc = H5O_get_loc(object_id)))
-        HGOTO_ERROR(H5E_OHDR, H5E_BADVALUE, FAIL, "unable to get object location from ID")
+    /* Make sure the ID is a file object */
+    if (H5I_is_file_object(object_id) != TRUE)
+        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "ID is not a file object");
 
-    if(H5AC_cork(oloc->file, oloc->addr, H5AC__SET_CORK, NULL) < 0)
-        HGOTO_ERROR(H5E_OHDR, H5E_CANTCORK, FAIL, "unable to cork an object")
+    /* Get the VOL object */
+    if (NULL == (vol_obj = H5VL_vol_object(object_id)))
+        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "invalid object ID");
+
+    /* Fill in location struct fields */
+    loc_params.type = H5VL_OBJECT_BY_SELF;
+    loc_params.obj_type = H5I_get_type(object_id);
+
+    /* Cork the object */
+    if(H5VL_object_optional(vol_obj, H5P_DATASET_XFER_DEFAULT, H5_REQUEST_NULL, H5VL_NATIVE_OBJECT_DISABLE_MDC_FLUSHES, &loc_params) < 0)
+        HGOTO_ERROR(H5E_OHDR, H5E_CANTCORK, FAIL, "unable to cork object");
 
 done:
-    FUNC_LEAVE_API(ret_value)
+    FUNC_LEAVE_API(ret_value);
 } /* H5Odisable_mdc_flushes() */
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5Oenable_mdc_flushes
+ * Function:    H5O_enable_mdc_flushes
  *
- * Purpose:	To "uncork" an object
- *		--release keeping dirty entries associated with the object 
- *		  in the metadata cache
+ * Purpose:     Private version of the metadata cache uncork function.
  *
- * Return:	Success:	Non-negative
- *		Failure:	Negative
+ * Return:      SUCCEED/FAIL
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5O_enable_mdc_flushes(H5O_loc_t *oloc)
+{
+    herr_t      ret_value = SUCCEED;
+
+    FUNC_ENTER_NOAPI(FAIL);
+
+    if (H5AC_cork(oloc->file, oloc->addr, H5AC__UNCORK, NULL) < 0)
+        HGOTO_ERROR(H5E_OHDR, H5E_CANTUNCORK, FAIL, "unable to uncork object");
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value);
+} /* H5O_enable_mdc_flushes() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:    H5Oenable_mdc_flushes
+ *
+ * Purpose:     "Uncork" an object, allowing dirty entries associated with
+ *              the object to be flushed.
  *
- * Programmer:	Vailin Choi
- *		January 2014
+ * Return:      Success:    Non-negative
+ *              Failure:    Negative
+ *
+ * Programmer:  Vailin Choi
+ *              January 2014
  *
  *-------------------------------------------------------------------------
  */
 herr_t
 H5Oenable_mdc_flushes(hid_t object_id)
 {
-    H5O_loc_t  *oloc;			/* Object location */
-    herr_t      ret_value = SUCCEED;	/* Return value */
+    H5VL_object_t       *vol_obj;               /* Object token of loc_id */
+    H5VL_loc_params_t   loc_params;             /* Location parameters */
+    herr_t              ret_value = SUCCEED;    /* Return value */
 
-    FUNC_ENTER_API(FAIL)
+    FUNC_ENTER_API(FAIL);
     H5TRACE1("e", "i", object_id);
 
-    /* Get the object's oloc */
-    if(NULL == (oloc = H5O_get_loc(object_id)))
-        HGOTO_ERROR(H5E_OHDR, H5E_BADVALUE, FAIL, "unable to get object location from ID")
+    /* Make sure the ID is a file object */
+    if (H5I_is_file_object(object_id) != TRUE)
+        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "ID is not a file object");
+
+    /* Get the VOL object */
+    if (NULL == (vol_obj = H5VL_vol_object(object_id)))
+        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "invalid object ID");
+
+    /* Fill in location struct fields */
+    loc_params.type = H5VL_OBJECT_BY_SELF;
+    loc_params.obj_type = H5I_get_type(object_id);
 
-    /* Set the value */
-    if(H5AC_cork(oloc->file, oloc->addr, H5AC__UNCORK, NULL) < 0)
-        HGOTO_ERROR(H5E_OHDR, H5E_CANTUNCORK, FAIL, "unable to uncork an object")
+    /* Uncork the object */
+    if (H5VL_object_optional(vol_obj, H5P_DATASET_XFER_DEFAULT, H5_REQUEST_NULL, H5VL_NATIVE_OBJECT_ENABLE_MDC_FLUSHES, &loc_params) < 0)
+        HGOTO_ERROR(H5E_OHDR, H5E_CANTUNCORK, FAIL, "unable to uncork object");
 
 done:
-    FUNC_LEAVE_API(ret_value)
+    FUNC_LEAVE_API(ret_value);
 } /* H5Oenable_mdc_flushes() */
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5Oare_mdc_flushes_disabled
+ * Function:    H5O_are_mdc_flushes_disabled
  *
- * Purpose:	Retrieve the object's "cork" status in the parameter "are_disabled":
- *		  TRUE if mdc flushes for the object is disabled
- *		  FALSE if mdc flushes for the object is not disabled
- *		Return error if the parameter "are_disabled" is not supplied
+ * Purpose:     Private version of cork status getter.
  *
- * Return:	Success:	Non-negative
- *		Failure:	Negative
+ * Return:      SUCCEED/FAIL
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5O_are_mdc_flushes_disabled(H5O_loc_t *oloc, hbool_t *are_disabled)
+{
+    herr_t      ret_value = SUCCEED;
+
+    FUNC_ENTER_NOAPI(FAIL);
+
+    HDassert(are_disabled);
+
+    if (H5AC_cork(oloc->file, oloc->addr, H5AC__GET_CORKED, are_disabled) < 0)
+        HGOTO_ERROR(H5E_OHDR, H5E_CANTGET, FAIL, "unable to retrieve object's cork status");
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* H5O_are_mdc_flushes_disabled() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:    H5Oare_mdc_flushes_disabled
+ *
+ * Purpose:     Retrieve the object's "cork" status in the parameter "are_disabled":
+ *                  TRUE if mdc flushes for the object is disabled
+ *                  FALSE if mdc flushes for the object is not disabled
  *
- * Programmer:	Vailin Choi
- *		January 2014
+ *              Return error if the parameter "are_disabled" is not supplied
+ *
+ * Return:      Success:    Non-negative
+ *              Failure:    Negative
+ *
+ * Programmer:  Vailin Choi
+ *              January 2014
  *
  *-------------------------------------------------------------------------
  */
 herr_t
 H5Oare_mdc_flushes_disabled(hid_t object_id, hbool_t *are_disabled)
 {
-    H5O_loc_t  *oloc;			/* Object location */
-    herr_t      ret_value = SUCCEED;	/* Return value */
+    H5VL_object_t       *vol_obj;               /* Object token of loc_id */
+    H5VL_loc_params_t   loc_params;             /* Location parameters */
+    herr_t              ret_value = SUCCEED;    /* Return value */
 
-    FUNC_ENTER_API(FAIL)
+    FUNC_ENTER_API(FAIL);
     H5TRACE2("e", "i*b", object_id, are_disabled);
 
-    /* Check args */
+    /* Sanity check */
+    if (!are_disabled)
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "unable to get object location from ID");
 
-    /* Get the object's oloc */
-    if(NULL == (oloc = H5O_get_loc(object_id)))
-        HGOTO_ERROR(H5E_OHDR, H5E_BADVALUE, FAIL, "unable to get object location from ID")
-    if(!are_disabled)
-        HGOTO_ERROR(H5E_OHDR, H5E_BADVALUE, FAIL, "unable to get object location from ID")
+    /* Make sure the ID is a file object */
+    if (H5I_is_file_object(object_id) != TRUE)
+        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "ID is not a file object");
+
+    /* Get the VOL object */
+    if (NULL == (vol_obj = H5VL_vol_object(object_id)))
+        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "invalid object ID");
+
+    /* Fill in location struct fields */
+    loc_params.type = H5VL_OBJECT_BY_SELF;
+    loc_params.obj_type = H5I_get_type(object_id);
 
     /* Get the cork status */
-    if(H5AC_cork(oloc->file, oloc->addr, H5AC__GET_CORKED, are_disabled) < 0)
-        HGOTO_ERROR(H5E_OHDR, H5E_CANTGET, FAIL, "unable to retrieve an object's cork status")
+    if (H5VL_object_optional(vol_obj, H5P_DATASET_XFER_DEFAULT, H5_REQUEST_NULL, H5VL_NATIVE_OBJECT_ARE_MDC_FLUSHES_DISABLED, &loc_params, are_disabled) < 0)
+        HGOTO_ERROR(H5E_OHDR, H5E_CANTGET, FAIL, "unable to retrieve object's cork status");
 
 done:
     FUNC_LEAVE_API(ret_value)
diff --git a/src/H5Oprivate.h b/src/H5Oprivate.h
index 354a00b..bcb8299 100644
--- a/src/H5Oprivate.h
+++ b/src/H5Oprivate.h
@@ -972,6 +972,11 @@ H5_DLL herr_t H5O_flush_common(H5O_loc_t *oloc, hid_t obj_id);
 H5_DLL herr_t H5O_refresh_metadata(hid_t oid, H5O_loc_t oloc);
 H5_DLL herr_t H5O_refresh_metadata_reopen(hid_t oid, H5G_loc_t *obj_loc, H5VL_t *vol_driver, hbool_t start_swmr);
 
+/* Cache corking functions */
+H5_DLL herr_t H5O_disable_mdc_flushes(H5O_loc_t *oloc);
+H5_DLL herr_t H5O_enable_mdc_flushes(H5O_loc_t *oloc);
+H5_DLL herr_t H5O_are_mdc_flushes_disabled(H5O_loc_t *oloc, hbool_t *are_disabled);
+
 /* Object copying routines */
 H5_DLL herr_t H5O_copy_header_map(const H5O_loc_t *oloc_src, H5O_loc_t *oloc_dst /*out */,
     H5O_copy_t *cpy_info, hbool_t inc_depth,
diff --git a/src/H5VLnative.h b/src/H5VLnative.h
index a8d5720..b2dd13d 100644
--- a/src/H5VLnative.h
+++ b/src/H5VLnative.h
@@ -71,6 +71,8 @@ typedef int H5VL_native_file_optional_t;
 #define H5VL_NATIVE_FILE_SET_LIBVER_BOUNDS              24  /* H5Fset_latest_format/libver_bounds   */
 #define H5VL_NATIVE_FILE_GET_MIN_DSET_OHDR_FLAG         25  /* H5Fget_dset_no_attrs_hint            */
 #define H5VL_NATIVE_FILE_SET_MIN_DSET_OHDR_FLAG         26  /* H5Fset_dset_no_attrs_hint            */
+#define H5VL_NATIVE_FILE_GET_MPI_ATOMICITY              27  /* H5Fget_mpi_atomicity                 */
+#define H5VL_NATIVE_FILE_SET_MPI_ATOMICITY              28  /* H5Fset_mpi_atomicity                 */
 
 /* Typedef and values for native VOL connector group optional VOL operations */
 typedef int H5VL_native_group_optional_t;
@@ -81,9 +83,12 @@ typedef int H5VL_native_group_optional_t;
 
 /* Typedef and values for native VOL connector object optional VOL operations */
 typedef int H5VL_native_object_optional_t;
-#define H5VL_NATIVE_OBJECT_GET_COMMENT      0   /* H5G|H5Oget_comment, H5Oget_comment_by_name   */
-#define H5VL_NATIVE_OBJECT_GET_INFO         1   /* H5Oget_info(_by_idx, _by_name)(2)            */
-#define H5VL_NATIVE_OBJECT_SET_COMMENT      2   /* H5G|H5Oset_comment, H5Oset_comment_by_name   */
+#define H5VL_NATIVE_OBJECT_GET_COMMENT                  0   /* H5G|H5Oget_comment, H5Oget_comment_by_name   */
+#define H5VL_NATIVE_OBJECT_GET_INFO                     1   /* H5Oget_info(_by_idx, _by_name)(2)            */
+#define H5VL_NATIVE_OBJECT_SET_COMMENT                  2   /* H5G|H5Oset_comment, H5Oset_comment_by_name   */
+#define H5VL_NATIVE_OBJECT_DISABLE_MDC_FLUSHES          3   /* H5Odisable_mdc_flushes                       */
+#define H5VL_NATIVE_OBJECT_ENABLE_MDC_FLUSHES           4   /* H5Oenable_mdc_flushes                        */
+#define H5VL_NATIVE_OBJECT_ARE_MDC_FLUSHES_DISABLED     5   /* H5Oare_mdc_flushes_disabled                  */
 
 #ifdef __cplusplus
 extern "C" {
diff --git a/src/H5VLnative_file.c b/src/H5VLnative_file.c
index 0ac70e3..bb77822 100644
--- a/src/H5VLnative_file.c
+++ b/src/H5VLnative_file.c
@@ -789,6 +789,24 @@ H5VL__native_file_optional(void *obj, hid_t H5_ATTR_UNUSED dxpl_id, void H5_ATTR
                 break;
             }
 
+        /* H5Fget_mpi_atomicity */
+        case H5VL_NATIVE_FILE_GET_MPI_ATOMICITY:
+            {
+                hbool_t *flag = (hbool_t *)HDva_arg(arguments, hbool_t *);
+                if (H5F_get_mpi_atomicity(f, flag) < 0)
+                    HGOTO_ERROR(H5E_FILE, H5E_CANTGET, FAIL, "cannot get MPI atomicity");
+                break;
+            }
+
+        /* H5Fset_mpi_atomicity */
+        case H5VL_NATIVE_FILE_SET_MPI_ATOMICITY:
+            {
+                hbool_t flag = (hbool_t)HDva_arg(arguments, int);
+                if (H5F_set_mpi_atomicity(f, flag) < 0)
+                    HGOTO_ERROR(H5E_FILE, H5E_CANTSET, FAIL, "cannot set MPI atomicity");
+                break;
+            }
+
         default:
             HGOTO_ERROR(H5E_VOL, H5E_UNSUPPORTED, FAIL, "invalid optional operation")
     } /* end switch */
diff --git a/src/H5VLnative_object.c b/src/H5VLnative_object.c
index de2a8a5..49d4b2c 100644
--- a/src/H5VLnative_object.c
+++ b/src/H5VLnative_object.c
@@ -487,6 +487,40 @@ H5VL__native_object_optional(void *obj, hid_t H5_ATTR_UNUSED dxpl_id,
                 break;
             }
 
+        /* H5Odisable_mdc_flushes */
+        case H5VL_NATIVE_OBJECT_DISABLE_MDC_FLUSHES:
+            {
+                H5O_loc_t  *oloc = loc.oloc;
+
+                if (H5O_disable_mdc_flushes(oloc) < 0)
+                    HGOTO_ERROR(H5E_OHDR, H5E_CANTCORK, FAIL, "unable to cork the metadata cache");
+
+                break;
+            }
+
+        /* H5Oenable_mdc_flushes */
+        case H5VL_NATIVE_OBJECT_ENABLE_MDC_FLUSHES:
+            {
+                H5O_loc_t  *oloc = loc.oloc;
+
+                if (H5O_enable_mdc_flushes(oloc) < 0)
+                    HGOTO_ERROR(H5E_OHDR, H5E_CANTUNCORK, FAIL, "unable to uncork the metadata cache");
+
+                break;
+            }
+
+        /* H5Oare_mdc_flushes_disabled */
+        case H5VL_NATIVE_OBJECT_ARE_MDC_FLUSHES_DISABLED:
+            {
+                H5O_loc_t  *oloc = loc.oloc;
+                hbool_t *are_disabled = (hbool_t *)HDva_arg(arguments, hbool_t *);
+
+                if (H5O_are_mdc_flushes_disabled(oloc, are_disabled) < 0)
+                    HGOTO_ERROR(H5E_OHDR, H5E_CANTGET, FAIL, "unable to determine metadata cache cork status");
+
+                break;
+            }
+
         default:
             HGOTO_ERROR(H5E_VOL, H5E_CANTGET, FAIL, "can't perform this operation on object");       
     } /* end switch */
diff --git a/test/cork.c b/test/cork.c
index 09076d2..06a520d 100644
--- a/test/cork.c
+++ b/test/cork.c
@@ -1529,11 +1529,13 @@ error:
 static unsigned
 test_objs_cork(hbool_t swmr, hbool_t new_format)
 {
-    hid_t       fid;                    /* HDF5 File ID */
-    hid_t       fapl;                   /* File access property list */
-    hid_t       gid, did, tid;      /* Object IDs */
-    hid_t   sid;            /* Dataspace ID */
-    hid_t   aid;            /* Attribute ID */
+    hid_t   fid = H5I_INVALID_HID;                  /* HDF5 File ID */
+    hid_t   fapl = H5I_INVALID_HID;                 /* File access property list */
+    hid_t   gid = H5I_INVALID_HID;
+    hid_t   did = H5I_INVALID_HID;
+    hid_t   tid = H5I_INVALID_HID;                  /* Object IDs */
+    hid_t   sid = H5I_INVALID_HID;                  /* Dataspace ID */
+    hid_t   aid = H5I_INVALID_HID;                  /* Attribute ID */
     hsize_t     dims[RANK];     /* Dataset dimension sizes */
     hbool_t     corked;         /* Cork status of an object */
     unsigned flags;             /* File access flags */
diff --git a/testpar/t_dset.c b/testpar/t_dset.c
index d4e556d..6c91a41 100644
--- a/testpar/t_dset.c
+++ b/testpar/t_dset.c
@@ -4162,7 +4162,7 @@ dataset_atomicity(void)
     }
 
     /* should fail */
-    ret = H5Fset_mpi_atomicity (fid , TRUE);
+    ret = H5Fset_mpi_atomicity(fid , TRUE);
     VRFY((ret == FAIL), "H5Fset_mpi_atomicity failed");
 
     if(MAINPROCESS){
@@ -4184,7 +4184,7 @@ dataset_atomicity(void)
     ret = H5Pclose(acc_tpl);
     VRFY((ret >= 0), "H5Pclose succeeded");
 
-    ret = H5Fset_mpi_atomicity (fid , TRUE);
+    ret = H5Fset_mpi_atomicity(fid , TRUE);
     VRFY((ret >= 0), "H5Fset_mpi_atomicity succeeded");
 
     /* open dataset1 (contiguous case) */
@@ -4203,7 +4203,7 @@ dataset_atomicity(void)
     }
 
     /* check that the atomicity flag is set */
-    ret = H5Fget_mpi_atomicity (fid , &atomicity);
+    ret = H5Fget_mpi_atomicity(fid , &atomicity);
     VRFY((ret >= 0), "atomcity get failed");
     VRFY((atomicity == TRUE), "atomcity set failed");
 
@@ -4272,7 +4272,7 @@ dataset_atomicity(void)
 
     atomicity = FALSE;
     /* check that the atomicity flag is set */
-    ret = H5Fget_mpi_atomicity (fid , &atomicity);
+    ret = H5Fget_mpi_atomicity(fid , &atomicity);
     VRFY((ret >= 0), "atomcity get failed");
     VRFY((atomicity == TRUE), "atomcity set failed");