[svn-r23487] use the core driver at the server side for the metadata fileinactive/mds

2 files changed, 523 insertions, 0 deletions

diff --git a/examples/h5_external_log_native_vol.c b/examples/h5_external_log_native_vol.c
new file mode 100644
index 0000000..024a115
--- /dev/null
+++ b/examples/h5_external_log_native_vol.c
@@ -0,0 +1,512 @@
+

+#include <stdio.h>

+#include <stdlib.h>

+#include <assert.h>

+#include "mpi.h"

+#include "hdf5.h"

+

+#define LOG 502

+

+/* Atrribute callbacks */

+static void *H5VL_log_attr_create(void *obj, H5VL_loc_params_t loc_params, const char *attr_name, hid_t acpl_id, hid_t aapl_id, hid_t dxpl_id, void **req);

+static herr_t H5VL_log_attr_close(void *attr, hid_t dxpl_id, void **req);

+

+/* Datatype callbacks */

+static void *H5VL_log_datatype_commit(void *obj, H5VL_loc_params_t loc_params, const char *name, hid_t type_id, hid_t lcpl_id, hid_t tcpl_id, hid_t tapl_id, hid_t dxpl_id, void **req);

+static void *H5VL_log_datatype_open(void *obj, H5VL_loc_params_t loc_params, const char *name, hid_t tapl_id, hid_t dxpl_id, void **req);

+static ssize_t H5VL_log_datatype_get_binary(void *obj, unsigned char *buf, size_t size, hid_t dxpl_id, void **req);

+static herr_t H5VL_log_datatype_close(void *dt, hid_t dxpl_id, void **req);

+

+/* Dataset callbacks */

+static void *H5VL_log_dataset_create(void *obj, H5VL_loc_params_t loc_params, const char *name, hid_t dcpl_id, hid_t dapl_id, hid_t dxpl_id, void **req);

+static void *H5VL_log_dataset_open(void *obj, H5VL_loc_params_t loc_params, const char *name, hid_t dapl_id, hid_t dxpl_id, void **req);

+static herr_t H5VL_log_dataset_read(void *dset, hid_t mem_type_id, hid_t mem_space_id,

+                                    hid_t file_space_id, hid_t plist_id, void *buf, void **req);

+static herr_t H5VL_log_dataset_write(void *dset, hid_t mem_type_id, hid_t mem_space_id,

+                                     hid_t file_space_id, hid_t plist_id, const void *buf, void **req);

+static herr_t H5VL_log_dataset_close(void *dset, hid_t dxpl_id, void **req);

+

+/* File callbacks */

+static void *H5VL_log_file_create(const char *name, unsigned flags, hid_t fcpl_id, hid_t fapl_id, hid_t dxpl_id, void **req);

+static void *H5VL_log_file_open(const char *name, unsigned flags, hid_t fapl_id, hid_t dxpl_id, void **req);

+static herr_t H5VL_log_file_get(void *file, H5VL_file_get_t get_type, hid_t dxpl_id, void **req, va_list arguments);

+static herr_t H5VL_log_file_close(void *file, hid_t dxpl_id, void **req);

+

+/* Group callbacks */

+static void *H5VL_log_group_create(void *obj, H5VL_loc_params_t loc_params, const char *name, hid_t gcpl_id, hid_t gapl_id, hid_t dxpl_id, void **req);

+static void *H5VL_log_group_open(void *obj, H5VL_loc_params_t loc_params, const char *name, hid_t gapl_id, hid_t dxpl_id, void **req);

+static herr_t H5VL_log_group_get(void *obj, H5VL_group_get_t get_type, hid_t dxpl_id, void **req, va_list arguments);

+static herr_t H5VL_log_group_close(void *grp, hid_t dxpl_id, void **req);

+

+/* Link callbacks */

+

+/* Object callbacks */

+static void *H5VL_log_object_open(void *obj, H5VL_loc_params_t loc_params, H5I_type_t *opened_type, hid_t dxpl_id, void **req);

+static herr_t H5VL_log_object_visit(void *obj, H5VL_loc_params_t loc_params, H5_index_t idx_type, 

+                                    H5_iter_order_t order, H5O_iterate_t op, void *op_data, hid_t dxpl_id, void **req);

+

+static const H5VL_class_t H5VL_log_g = {

+    LOG,

+    "log",					/* name */

+    NULL,                                       /* initialize */

+    NULL,                                       /* terminate */

+    sizeof(hid_t),

+    NULL,

+    NULL,

+    {                                           /* attribute_cls */

+        NULL, //H5VL_log_attr_create,                /* create */

+        NULL, //H5VL_log_attr_open,                  /* open */

+        NULL, //H5VL_log_attr_read,                  /* read */

+        NULL, //H5VL_log_attr_write,                 /* write */

+        NULL, //H5VL_log_attr_get,                   /* get */

+        NULL, //H5VL_log_attr_remove,                /* remove */

+        NULL  //H5VL_log_attr_close                  /* close */

+    },

+    {                                           /* datatype_cls */

+        H5VL_log_datatype_commit,            /* commit */

+        H5VL_log_datatype_open,              /* open */

+        H5VL_log_datatype_get_binary,          /* get_size */

+        H5VL_log_datatype_close              /* close */

+    },

+    {                                           /* dataset_cls */

+        H5VL_log_dataset_create,             /* create */

+        H5VL_log_dataset_open,               /* open */

+        H5VL_log_dataset_read,               /* read */

+        H5VL_log_dataset_write,              /* write */

+        NULL, //H5VL_log_dataset_set_extent,         /* set extent */

+        NULL, //H5VL_log_dataset_get,                /* get */

+        H5VL_log_dataset_close               /* close */

+    },

+    {                                           /* file_cls */

+        H5VL_log_file_create,                /* create */

+        H5VL_log_file_open,                  /* open */

+        NULL, //H5VL_log_file_flush,                 /* flush */

+        H5VL_log_file_get,                   /* get */

+        NULL, //H5VL_log_file_misc,                  /* misc */

+        NULL, //H5VL_log_file_optional,              /* optional */

+        H5VL_log_file_close                  /* close */

+    },

+    {                                           /* group_cls */

+        H5VL_log_group_create,               /* create */

+        NULL, //H5VL_log_group_open,                 /* open */

+        NULL, //H5VL_log_group_get,                  /* get */

+        H5VL_log_group_close                 /* close */

+    },

+    {                                           /* link_cls */

+        NULL, //H5VL_log_link_create,                /* create */

+        NULL, //H5VL_log_link_move,                  /* move */

+        NULL, //H5VL_log_link_iterate,               /* iterate */

+        NULL, //H5VL_log_link_get,                   /* get */

+        NULL  //H5VL_log_link_remove                 /* remove */

+    },

+    {                                           /* object_cls */

+        H5VL_log_object_open,                /* open */

+        NULL, //H5VL_log_object_copy,                /* copy */

+        H5VL_log_object_visit,               /* visit */

+        NULL, //H5VL_log_object_get,                 /* get */

+        NULL, //H5VL_log_object_misc,                /* misc */

+        NULL, //H5VL_log_object_optional,            /* optional */

+        NULL  //H5VL_log_object_close                /* close */

+    },

+    {

+        NULL,

+        NULL,

+        NULL

+    }

+};

+

+typedef struct H5VL_log_t {

+    void   *under_object;

+    H5VL_t *under_plugin;

+} H5VL_log_t;

+

+static herr_t

+visit_cb(hid_t oid, const char *name,

+         const H5O_info_t *oinfo, void *udata)

+{

+    ssize_t len;

+    char n[25];

+

+    if(H5Iget_type(oid) == H5I_GROUP) {

+        len = H5VLget_plugin_name(oid, n, 50);

+        printf ("Visiting GROUP VOL name = %s  %d\n", n, len);

+    }

+    if(H5Iget_type(oid) == H5I_DATASET) 

+        printf("visiting dataset\n");

+    if(H5Iget_type(oid) == H5I_DATATYPE) 

+        printf("visiting datatype\n");

+

+    return 1;

+} /* end h5_verify_cached_stabs_cb() */

+

+int main(int argc, char **argv) {

+        const char file_name[]="large_dataset.h5";

+	const char group_name[]="/Group";

+	const char dataset_name[]="Data";

+	char fullpath[500];

+	hid_t file_id;

+	hid_t group_id;

+	hid_t dataspaceId;

+        hid_t datasetId;

+        hid_t acc_tpl;

+        hid_t under_fapl;

+        hid_t vol_id;

+        hid_t int_id;

+        hid_t attr;

+        hid_t space;

+	const unsigned int nelem=60;

+	int *data;

+	unsigned int i;

+	hsize_t dims[1];

+        ssize_t len;

+        char name[25];

+        static hsize_t      ds_size[2] = {10, 20};

+

+	MPI_Init(&argc, &argv);

+

+        under_fapl = H5Pcreate (H5P_FILE_ACCESS);

+        H5Pset_fapl_native(under_fapl);

+        vol_id = H5VLregister (&H5VL_log_g);

+        acc_tpl = H5Pcreate (H5P_FILE_ACCESS);

+        H5Pset_vol(acc_tpl, vol_id, &under_fapl);

+

+	file_id = H5Fcreate(file_name, H5F_ACC_TRUNC, H5P_DEFAULT, acc_tpl);

+        len = H5VLget_plugin_name(file_id, name, 25);

+        printf ("FILE VOL name = %s  %d\n", name, len);

+

+	group_id = H5Gcreate2(file_id, group_name, H5P_DEFAULT, H5P_DEFAULT, H5P_DEFAULT);

+        len = H5VLget_plugin_name(group_id, name, 50);

+        printf ("GROUP VOL name = %s  %d\n", name, len);

+

+        int_id = H5Tcopy(H5T_NATIVE_INT);

+        H5Tcommit2(file_id, "int", int_id, H5P_DEFAULT, H5P_DEFAULT, H5P_DEFAULT);

+        len = H5VLget_plugin_name(int_id, name, 50);

+        printf ("DT COMMIT name = %s  %d\n", name, len);

+        H5Tclose(int_id);

+

+        int_id = H5Topen(file_id, "int", H5P_DEFAULT);

+        len = H5VLget_plugin_name(int_id, name, 50);

+        printf ("DT OPEN name = %s  %d\n", name, len);

+        H5Tclose(int_id);

+

+        int_id = H5Oopen(file_id,"int",H5P_DEFAULT);

+        len = H5VLget_plugin_name(int_id, name, 50);

+        printf ("DT OOPEN name = %s  %d\n", name, len);

+

+        len = H5Fget_name(file_id, name, 50);

+        printf("name = %d  %s\n", len, name);

+

+	data = malloc (sizeof(int)*nelem);

+	for(i=0;i<nelem;++i)

+	  data[i]=i;

+

+	dims [0] = 60;

+	dataspaceId = H5Screate_simple(1, dims, NULL); 

+        space = H5Screate_simple (2, ds_size, ds_size);

+

+	sprintf(fullpath,"%s/%s",group_name,dataset_name);

+	datasetId = H5Dcreate(file_id,fullpath,H5T_NATIVE_INT,dataspaceId,H5P_DEFAULT,H5P_DEFAULT,H5P_DEFAULT);

+	H5Sclose(dataspaceId);

+

+        len = H5VLget_plugin_name(datasetId, name, 50);

+        printf ("DSET name = %s  %d\n", name, len);

+

+	H5Dwrite(datasetId, H5T_NATIVE_INT, H5S_ALL, H5S_ALL, H5P_DEFAULT, data);

+	H5Dclose(datasetId);

+

+        H5Ovisit(file_id, H5_INDEX_NAME, H5_ITER_NATIVE, visit_cb, NULL);

+

+	free (data);

+        H5Oclose(int_id);

+        H5Sclose (space);

+	H5Gclose(group_id);

+#if 0

+

+        attr = H5Acreate2(group_id, "attr1", int_id, space, H5P_DEFAULT, H5P_DEFAULT);

+        int_id = H5Aget_type(attr);

+        len = H5VLget_plugin_name(int_id, name, 50);

+        printf ("DT OPEN name = %s  %d\n", name, len);

+

+        H5Aclose (attr);

+

+        int_id = H5Oopen(file_id,"int",H5P_DEFAULT);

+        len = H5VLget_plugin_name(int_id, name, 50);

+        printf ("DT OOPEN name = %s  %d\n", name, len);

+        H5Oclose(int_id);

+

+

+	H5Fclose(file_id);

+	file_id = H5Fopen(file_name, H5F_ACC_RDWR, H5P_DEFAULT);//acc_tpl);

+        H5Fflush(file_id, H5F_SCOPE_GLOBAL);

+#endif

+

+	H5Fclose(file_id);

+        H5Pclose(acc_tpl);

+        H5Pclose(under_fapl);

+        

+        H5VLunregister (vol_id);

+	MPI_Finalize();

+

+	return 0;

+}

+

+static void *

+H5VL_log_file_create(const char *name, unsigned flags, hid_t fcpl_id, hid_t fapl_id, hid_t dxpl_id, void **req)

+{

+    hid_t under_fapl;

+    H5VL_log_t *file;

+

+    file = (H5VL_log_t *)calloc(1, sizeof(H5VL_log_t));

+

+    under_fapl = *((hid_t *)H5Pget_vol_info(fapl_id));

+    file->under_object = H5VLfile_create(&(file->under_plugin), name, flags, fcpl_id, under_fapl, dxpl_id, req);

+

+    printf("------- LOG H5Fcreate\n");

+    return (void *)file;

+}

+

+static void *

+H5VL_log_file_open(const char *name, unsigned flags, hid_t fapl_id, hid_t dxpl_id, void **req)

+{

+    hid_t under_fapl;

+    H5VL_log_t *file;

+

+    file = (H5VL_log_t *)calloc(1, sizeof(H5VL_log_t));

+

+    under_fapl = *((hid_t *)H5Pget_vol_info(fapl_id));

+    file->under_object = H5VLfile_open(&(file->under_plugin), name, flags, under_fapl, dxpl_id, req);

+

+    printf("------- LOG H5Fopen\n");

+    return (void *)file;

+}

+

+static herr_t 

+H5VL_log_file_get(void *file, H5VL_file_get_t get_type, hid_t dxpl_id, void **req, va_list arguments)

+{

+    H5VL_log_t *f = (H5VL_log_t *)file;

+

+    H5VLfile_get(f->under_object, f->under_plugin, get_type, dxpl_id, req, arguments);

+

+    printf("------- LOG H5Fget %d\n", get_type);

+    return 1;

+}

+static herr_t 

+H5VL_log_file_close(void *file, hid_t dxpl_id, void **req)

+{

+    H5VL_log_t *f = (H5VL_log_t *)file;

+

+    H5VLfile_close(f->under_object, f->under_plugin, dxpl_id, req);

+    free(f);

+

+    printf("------- LOG H5Fclose\n");

+    return 1;

+}

+

+static void *

+H5VL_log_group_create(void *obj, H5VL_loc_params_t loc_params, const char *name, 

+                      hid_t gcpl_id, hid_t gapl_id, hid_t dxpl_id, void **req)

+{

+    H5VL_log_t *group;

+    H5VL_log_t *o = (H5VL_log_t *)obj;

+

+    group = (H5VL_log_t *)calloc(1, sizeof(H5VL_log_t));

+

+    group->under_object = H5VLgroup_create(o->under_object, loc_params, o->under_plugin, name, gcpl_id,  gapl_id, dxpl_id, req);

+    group->under_plugin = o->under_plugin;

+

+    printf("------- LOG H5Gcreate\n");

+    return (void *)group;

+}

+

+static herr_t 

+H5VL_log_group_close(void *grp, hid_t dxpl_id, void **req)

+{

+    H5VL_log_t *g = (H5VL_log_t *)grp;

+

+    H5VLgroup_close(g->under_object, g->under_plugin, dxpl_id, req);

+    free(g);

+

+    printf("------- LOG H5Gclose\n");

+    return 1;

+}

+

+static void *

+H5VL_log_datatype_commit(void *obj, H5VL_loc_params_t loc_params, const char *name, 

+                         hid_t type_id, hid_t lcpl_id, hid_t tcpl_id, hid_t tapl_id, hid_t dxpl_id, void **req)

+{

+    H5VL_log_t *dt;

+    H5VL_log_t *o = (H5VL_log_t *)obj;

+

+    dt = (H5VL_log_t *)calloc(1, sizeof(H5VL_log_t));

+

+    dt->under_object = H5VLdatatype_commit(o->under_object, loc_params, o->under_plugin, name, 

+                                           type_id, lcpl_id, tcpl_id, tapl_id, dxpl_id, req);

+    dt->under_plugin = o->under_plugin;

+

+    printf("------- LOG H5Tcommit\n");

+    return dt;

+}

+static void *

+H5VL_log_datatype_open(void *obj, H5VL_loc_params_t loc_params, const char *name, hid_t tapl_id, hid_t dxpl_id, void **req)

+{

+    H5VL_log_t *dt;

+    H5VL_log_t *o = (H5VL_log_t *)obj;  

+

+    dt = (H5VL_log_t *)calloc(1, sizeof(H5VL_log_t));

+

+    dt->under_object = H5VLdatatype_open(o->under_object, loc_params, o->under_plugin, name, tapl_id, dxpl_id, req);

+    dt->under_plugin = o->under_plugin;

+

+    printf("------- LOG H5Topen\n");

+    return (void *)dt;

+}

+

+static ssize_t 

+H5VL_log_datatype_get_binary(void *obj, unsigned char *buf, size_t size, hid_t dxpl_id, void **req)

+{

+    H5VL_log_t *o = (H5VL_log_t *)obj;

+    ssize_t ret_value;

+

+    ret_value = H5VLdatatype_get_binary(o->under_object, o->under_plugin, buf, size, dxpl_id, req);

+

+    printf("------- LOG get_binary\n");

+    return ret_value;

+}

+

+static herr_t 

+H5VL_log_datatype_close(void *dt, hid_t dxpl_id, void **req)

+{

+    H5VL_log_t *type = (H5VL_log_t *)dt;

+

+    assert(type->under_object);

+    assert(type->under_plugin);

+

+    H5VLdatatype_close(type->under_object, type->under_plugin, dxpl_id, req);

+    free(type);

+

+    printf("------- LOG H5Tclose\n");

+    return 1;

+}

+

+static void *

+H5VL_log_object_open(void *obj, H5VL_loc_params_t loc_params, H5I_type_t *opened_type, hid_t dxpl_id, void **req)

+{

+    H5VL_log_t *new_obj;

+    H5VL_log_t *o = (H5VL_log_t *)obj;

+

+    new_obj = (H5VL_log_t *)calloc(1, sizeof(H5VL_log_t));

+    

+    new_obj->under_object = H5VLobject_open(o->under_object, loc_params, o->under_plugin, opened_type, dxpl_id, req);

+    new_obj->under_plugin = o->under_plugin;

+

+    printf("------- LOG H5Oopen\n");

+    return (void *)new_obj;

+}

+

+static herr_t 

+H5VL_log_object_visit(void *obj, H5VL_loc_params_t loc_params, H5_index_t idx_type, 

+                      H5_iter_order_t order, H5O_iterate_t op, void *op_data, hid_t dxpl_id, void **req)

+{

+    H5VL_log_t *o = (H5VL_log_t *)obj;

+

+    H5VLobject_visit(o->under_object, loc_params, o->under_plugin, idx_type, order, op, op_data, dxpl_id, req);

+

+    printf("------- LOG H5Ovisit\n");

+    return 1;

+}

+

+static void *

+H5VL_log_dataset_create(void *obj, H5VL_loc_params_t loc_params, const char *name, hid_t dcpl_id, hid_t dapl_id, hid_t dxpl_id, void **req) 

+{

+    H5VL_log_t *dset;

+    H5VL_log_t *o = (H5VL_log_t *)obj;

+

+    dset = (H5VL_log_t *)calloc(1, sizeof(H5VL_log_t));

+

+    dset->under_object = H5VLdataset_create(o->under_object, loc_params, o->under_plugin, name, dcpl_id,  dapl_id, dxpl_id, req);

+    dset->under_plugin = o->under_plugin;

+

+    printf("------- LOG H5Dcreate\n");

+    return (void *)dset;

+}

+

+static void *

+H5VL_log_dataset_open(void *obj, H5VL_loc_params_t loc_params, const char *name, hid_t dapl_id, hid_t dxpl_id, void **req)

+{

+    H5VL_log_t *dset;

+    H5VL_log_t *o = (H5VL_log_t *)obj;

+

+    dset = (H5VL_log_t *)calloc(1, sizeof(H5VL_log_t));

+

+    dset->under_object = H5VLdataset_open(o->under_object, loc_params, o->under_plugin, name, dapl_id, dxpl_id, req);

+    dset->under_plugin = o->under_plugin;

+

+    printf("------- LOG H5Dopen\n");

+    return (void *)dset;

+}

+

+static herr_t 

+H5VL_log_dataset_read(void *dset, hid_t mem_type_id, hid_t mem_space_id,

+                      hid_t file_space_id, hid_t plist_id, void *buf, void **req)

+{

+    H5VL_log_t *d = (H5VL_log_t *)dset;

+

+    H5VLdataset_read(d->under_object, d->under_plugin, mem_type_id, mem_space_id, file_space_id, 

+                     plist_id, buf, req);

+

+    printf("------- LOG H5Dread\n");

+    return 1;

+}

+static herr_t 

+H5VL_log_dataset_write(void *dset, hid_t mem_type_id, hid_t mem_space_id,

+                       hid_t file_space_id, hid_t plist_id, const void *buf, void **req)

+{

+    H5VL_log_t *d = (H5VL_log_t *)dset;

+

+    H5VLdataset_write(d->under_object, d->under_plugin, mem_type_id, mem_space_id, file_space_id, 

+                     plist_id, buf, req);

+

+    printf("------- LOG H5Dwrite\n");

+    return 1;

+}

+static herr_t 

+H5VL_log_dataset_close(void *dset, hid_t dxpl_id, void **req)

+{

+    H5VL_log_t *d = (H5VL_log_t *)dset;

+

+    H5VLdataset_close(d->under_object, d->under_plugin, dxpl_id, req);

+    free(d);

+

+    printf("------- LOG H5Dclose\n");

+    return 1;

+}

+

+#if 0

+static void *H5VL_log_attr_create(void *obj, H5VL_loc_params_t loc_params, const char *attr_name, hid_t acpl_id, hid_t aapl_id, hid_t dxpl_id, void **req){    

+static herr_t H5VL_log_attr_close(void *attr, hid_t dxpl_id, void **req){

+

+/* Datatype callbacks */

+

+

+/* Dataset callbacks */

+static void *H5VL_log_dataset_create(void *obj, H5VL_loc_params_t loc_params, const char *name, hid_t dcpl_id, hid_t dapl_id, hid_t dxpl_id, void **req){

+static herr_t H5VL_log_dataset_close(void *dset, hid_t dxpl_id, void **req){

+

+/* File callbacks */

+

+    

+static void *H5VL_log_file_open(const char *name, unsigned flags, hid_t fapl_id, hid_t dxpl_id, void **req){

+

+

+/* Group callbacks */

+

+static void *H5VL_log_group_open(void *obj, H5VL_loc_params_t loc_params, const char *name, hid_t gapl_id, hid_t dxpl_id, void **req){

+static herr_t H5VL_log_group_get(void *obj, H5VL_group_get_t get_type, hid_t dxpl_id, void **req, va_list arguments){

+

+

+/* Link callbacks */

+

+/* Object callbacks */

+

+

+#endif

diff --git a/src/H5MDserver.c b/src/H5MDserver.c
index 788792a..34e6324 100644
--- a/src/H5MDserver.c
+++ b/src/H5MDserver.c
@@ -41,6 +41,7 @@
 #include "H5Eprivate.h"		/* Error handling		  	*/
 #include "H5Fprivate.h"		/* File access				*/
 #include "H5Fpkg.h"             /* File pkg                             */
+#include "H5FDcore.h"           /* Core file driver                    */
 #include "H5FDmpi.h"            /* MPI-based file drivers		*/
 #include "H5FDmulti.h"          /* MULTI-based file drivers		*/
 #include "H5FDmds.h"            /* MDS file driver      		*/
@@ -323,6 +324,11 @@ H5MD__file_create_func(uint8_t *p, int source)
     if(H5VL__decode_file_create_params(p, &mds_filename, &flags, &fcpl_id, &fapl_id) < 0)
         HGOTO_ERROR(H5E_SYM, H5E_CANTDECODE, FAIL, "can't decode file create params");
 
+    /* use the core driver for the metadata file for now */
+    if(H5Pset_fapl_core(fapl_id, 1048576, TRUE) < 0){
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTINIT, FAIL, "failed to set core vfd");
+    }
+
     /* Create a split fapl with the decoded fapl used for the metadata file access and
        a stub fapl (temp_fapl) used for raw data file to manage the EOA */
     split_fapl = H5Pcreate(H5P_FILE_ACCESS);
@@ -431,6 +437,11 @@ H5MD__file_open_func(uint8_t *p, int source)
     if(H5VL__decode_file_open_params(p, &mds_filename, &flags, &fapl_id) < 0)
         HGOTO_ERROR(H5E_SYM, H5E_CANTDECODE, FAIL, "can't decode file open params");
 
+    /* use the core driver for the metadata file for now */
+    if(H5Pset_fapl_core(fapl_id, 1048576, TRUE) < 0){
+        HGOTO_ERROR(H5E_PLIST, H5E_CANTINIT, FAIL, "failed to set core vfd");
+    }
+
     /* Create a split fapl with the decoded fapl used for the metadata file access and
        a stub fapl (temp_fapl) used for raw data file to manage the EOA */
     split_fapl = H5Pcreate(H5P_FILE_ACCESS);