[svn-r25582] Dynamic VOL plugin loading:

 - add support for searching for plugins by name in the H5PL interface
 - add support for searching for VOL plugins and returning the plugin structure
 - implement H5VLregister_by_name
 - add tests similar to the filter plugin tests
 - still needs some refactoring and better test framework and cmake support.

7 files changed, 275 insertions, 113 deletions

diff --git a/src/H5PL.c b/src/H5PL.c
index 21bc0f2..3ec66e8 100644
--- a/src/H5PL.c
+++ b/src/H5PL.c
@@ -27,6 +27,7 @@
 #include "H5Eprivate.h"		/* Error handling		  	*/
 #include "H5MMprivate.h"	/* Memory management			*/
 #include "H5PLprivate.h"	/* Plugin       			*/
+#include "H5VLprivate.h"	/* VOL          			*/
 #include "H5Zprivate.h"		/* Filter pipeline			*/
 
 
@@ -96,9 +97,10 @@ typedef const void *(*H5PL_get_plugin_info_t)(void);
 
 /* Type for the list of info for opened plugin libraries */
 typedef struct H5PL_table_t {
-    H5PL_type_t pl_type;			/* plugin type	     */
-    int         pl_id;                          /* ID for the plugin */
-    H5PL_HANDLE handle;			/* plugin handle     */
+    H5PL_type_t pl_type;		/* plugin type	      */
+    int         pl_id;                  /* ID for the plugin  */
+    const char *pl_name;                /* name of the plugin */
+    H5PL_HANDLE handle;			/* plugin handle      */
 } H5PL_table_t;
 
 
@@ -107,9 +109,9 @@ typedef struct H5PL_table_t {
 /********************/
 
 static herr_t H5PL__init_path_table(void);
-static htri_t H5PL__find(H5PL_type_t plugin_type, int type_id, char *dir, const void **info);
-static htri_t H5PL__open(H5PL_type_t pl_type, char *libname, int plugin_id, const void **pl_info);
-static htri_t H5PL__search_table(H5PL_type_t plugin_type, int type_id, const void **info);
+static htri_t H5PL__find(H5PL_type_t plugin_type, int type_id, const char *plugin_name, char *dir, const void **info);
+static htri_t H5PL__open(H5PL_type_t pl_type, char *libname, int plugin_id, const char *plugin_name, const void **pl_info);
+static htri_t H5PL__search_table(H5PL_type_t plugin_type, int type_id, const char *plugin_name, const void **info);
 static herr_t H5PL__close(H5PL_HANDLE handle);
 
 
@@ -132,6 +134,11 @@ static size_t		H5PL_table_alloc_g = 0;
 static size_t		H5PL_table_used_g = 0;
 static H5PL_table_t     *H5PL_table_g = NULL;
 
+/* Table for opened vol plugin libraries */
+static size_t		H5PL_vol_table_alloc_g = 0;
+static size_t		H5PL_vol_table_used_g = 0;
+static H5PL_table_t     *H5PL_vol_table_g = NULL;
+
 /* Table of location paths for plugin libraries */
 static char             *H5PL_path_table_g[H5PL_MAX_PATH_NUM];
 static size_t           H5PL_num_paths_g = 0;
@@ -231,10 +238,20 @@ H5PL_term_interface(void)
         for(u = 0; u < H5PL_table_used_g; u++)
             H5PL__close((H5PL_table_g[u]).handle);
 
+	/* Close opened dynamic vol libraries */
+        for(u = 0; u < H5PL_vol_table_used_g; u++) {
+            H5PL__close((H5PL_vol_table_g[u]).handle);
+            HDfree(H5PL_vol_table_g[u].pl_name);
+        }
+
 	/* Free the table of dynamic libraries */
 	H5PL_table_g = (H5PL_table_t *)H5MM_xfree(H5PL_table_g);
 	H5PL_table_used_g = H5PL_table_alloc_g = 0;
 
+	/* Free the table of dynamic vol libraries */
+	H5PL_vol_table_g = (H5PL_table_t *)H5MM_xfree(H5PL_vol_table_g);
+	H5PL_vol_table_used_g = H5PL_vol_table_alloc_g = 0;
+
         /* Free the table of search paths */
         for(u = 0; u < H5PL_num_paths_g; u++)
             if(H5PL_path_table_g[u])
@@ -253,9 +270,9 @@ H5PL_term_interface(void)
 /*-------------------------------------------------------------------------
  * Function:	H5PL_load
  *
- * Purpose:	Given the plugin type and identifier, this function searches
- *              and/or loads a dynamic plugin library first among the already
- *              opened libraries then in the designated location paths.
+ * Purpose:	Given the plugin type and identifier and/or name, this function
+ *              searches and/or loads a dynamic plugin library first among the 
+ *              already opened libraries then in the designated location paths.
  *
  * Return:	Non-NULL on success/NULL on failure
  *
@@ -265,7 +282,7 @@ H5PL_term_interface(void)
  *-------------------------------------------------------------------------
  */
 const void *
-H5PL_load(H5PL_type_t type, int id)
+H5PL_load(H5PL_type_t type, int id, const char *name)
 {
     htri_t      found;               /* Whether the plugin was found */
     const void  *plugin_info = NULL;
@@ -285,7 +302,7 @@ H5PL_load(H5PL_type_t type, int id)
             HGOTO_ERROR(H5E_PLUGIN, H5E_CANTINIT, NULL, "can't initialize search path table")
 
     /* Search in the table of already loaded plugin libraries */
-    if((found = H5PL__search_table(type, id, &plugin_info)) < 0)
+    if((found = H5PL__search_table(type, id, name, &plugin_info)) < 0)
         HGOTO_ERROR(H5E_PLUGIN, H5E_CANTGET, NULL, "search in table failed")
 
     /* If not found, iterate through the path table to find the right dynamic library */
@@ -293,7 +310,7 @@ H5PL_load(H5PL_type_t type, int id)
         size_t	   i;                   /* Local index variable */
 
         for(i = 0; i < H5PL_num_paths_g; i++) {
-            if((found = H5PL__find(type, id, H5PL_path_table_g[i], &plugin_info)) < 0)
+            if((found = H5PL__find(type, id, name, H5PL_path_table_g[i], &plugin_info)) < 0)
                 HGOTO_ERROR(H5E_PLUGIN, H5E_CANTGET, NULL, "search in paths failed")
      
             /* Break out if found */
@@ -387,7 +404,7 @@ done:
  */
 #ifndef H5_HAVE_WIN32_API
 static htri_t
-H5PL__find(H5PL_type_t plugin_type, int type_id, char *dir, const void **info)
+H5PL__find(H5PL_type_t plugin_type, int type_id, const char *plugin_name, char *dir, const void **info)
 {
     char           *pathname = NULL;
     DIR            *dirp = NULL;
@@ -425,8 +442,8 @@ H5PL__find(H5PL_type_t plugin_type, int type_id, char *dir, const void **info)
             if(S_ISDIR(my_stat.st_mode))
                 continue;
 
-            /* Attempt to open the dynamic library as a filter library */
-            if((found_in_dir = H5PL__open(plugin_type, pathname, type_id, info)) < 0)
+            /* Attempt to open the dynamic library */
+            if((found_in_dir = H5PL__open(plugin_type, pathname, type_id, plugin_name, info)) < 0)
                 HGOTO_ERROR(H5E_PLUGIN, H5E_CANTGET, FAIL, "search in directory failed")
             if(found_in_dir) {
                 /* Indicate success */
@@ -449,7 +466,7 @@ done:
 } /* end H5PL__find() */
 #else /* H5_HAVE_WIN32_API */
 static htri_t
-H5PL__find(H5PL_type_t plugin_type, int type_id, char *dir, const void **info)
+H5PL__find(H5PL_type_t plugin_type, int type_id, const char *plugin_name, char *dir, const void **info)
 {
     WIN32_FIND_DATA fdFile;
     HANDLE          hFind;
@@ -482,7 +499,7 @@ H5PL__find(H5PL_type_t plugin_type, int type_id, char *dir, const void **info)
             if(fdFile.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY)
                 continue;
 
-            if((found_in_dir = H5PL__open(plugin_type, pathname, type_id, info)) < 0)
+            if((found_in_dir = H5PL__open(plugin_type, pathname, type_id, plugin_name, info)) < 0)
                 HGOTO_ERROR(H5E_PLUGIN, H5E_CANTGET, FAIL, "search in directory failed")
             if(found_in_dir) {
                 /* Indicate success */
@@ -522,7 +539,7 @@ done:
  *-------------------------------------------------------------------------
  */
 static htri_t
-H5PL__open(H5PL_type_t pl_type, char *libname, int pl_id, const void **pl_info)
+H5PL__open(H5PL_type_t pl_type, char *libname, int pl_id, const char *pl_name, const void **pl_info)
 {
     H5PL_HANDLE    handle = NULL;
     htri_t         ret_value = FALSE;
@@ -546,45 +563,108 @@ H5PL__open(H5PL_type_t pl_type, char *libname, int pl_id, const void **pl_info)
                 HGOTO_ERROR(H5E_PLUGIN, H5E_CLOSEERROR, FAIL, "can't close dynamic library")
         } /* end if */
         else {
-            const H5Z_class2_t *plugin_info;
-
-            /* Invoke H5PLget_plugin_info to verify this is the right library we are looking for.
-             * Move on if it isn't.
-             */
-            if(NULL == (plugin_info = (const H5Z_class2_t *)(*get_plugin_info)())) {
-                if(H5PL__close(handle) < 0)
-                    HGOTO_ERROR(H5E_PLUGIN, H5E_CLOSEERROR, FAIL, "can't close dynamic library")
-                HGOTO_ERROR(H5E_PLUGIN, H5E_CANTGET, FAIL, "can't get plugin info")
-            } /* end if */
-
-            /* Successfully found plugin library, check if it's the right one */
-            if(plugin_info->id == pl_id) {
-                /* Expand the table if it is too small */
-                if(H5PL_table_used_g >= H5PL_table_alloc_g) {
-                    size_t n = MAX(H5Z_MAX_NFILTERS, 2 * H5PL_table_alloc_g);
-                    H5PL_table_t *table = (H5PL_table_t *)H5MM_realloc(H5PL_table_g, n * sizeof(H5PL_table_t));
-
-                    if(!table)
-                        HGOTO_ERROR(H5E_RESOURCE, H5E_CANTALLOC, FAIL, "unable to extend dynamic library table")
-
-                    H5PL_table_g = table;
-                    H5PL_table_alloc_g = n;
-                } /* end if */
-
-                (H5PL_table_g[H5PL_table_used_g]).handle = handle;
-                (H5PL_table_g[H5PL_table_used_g]).pl_type = pl_type;
-                (H5PL_table_g[H5PL_table_used_g]).pl_id = plugin_info->id;
-                H5PL_table_used_g++;
-
-                /* Set the plugin info to return */
-                *pl_info = (const void *)plugin_info;
-     
-                /* Indicate success */
-                ret_value = TRUE;
-            } /* end if */
-            else
-                if(H5PL__close(handle) < 0)
-                    HGOTO_ERROR(H5E_PLUGIN, H5E_CLOSEERROR, FAIL, "can't close dynamic library")
+            switch(pl_type) {
+            case H5PL_TYPE_FILTER:
+                {
+                    const H5Z_class2_t *plugin_info;
+
+                    /* Invoke H5PLget_plugin_info to verify this is the right library we are looking for.
+                     * Move on if it isn't.
+                     */
+                    if(NULL == (plugin_info = (const H5Z_class2_t *)(*get_plugin_info)())) {
+                        if(H5PL__close(handle) < 0)
+                            HGOTO_ERROR(H5E_PLUGIN, H5E_CLOSEERROR, FAIL, "can't close dynamic library")
+                        HGOTO_ERROR(H5E_PLUGIN, H5E_CANTGET, FAIL, "can't get plugin info")
+                    } /* end if */
+
+                    /* Successfully found plugin library, check if it's the right one */
+                    if(plugin_info->id == pl_id) {
+                        /* Expand the table if it is too small */
+                        if(H5PL_table_used_g >= H5PL_table_alloc_g) {
+                            size_t n = MAX(H5Z_MAX_NFILTERS, 2 * H5PL_table_alloc_g);
+                            H5PL_table_t *table = (H5PL_table_t *)H5MM_realloc(H5PL_table_g, n * sizeof(H5PL_table_t));
+
+                            if(!table)
+                                HGOTO_ERROR(H5E_RESOURCE, H5E_CANTALLOC, FAIL, "unable to extend dynamic library table")
+
+                            H5PL_table_g = table;
+                            H5PL_table_alloc_g = n;
+                        } /* end if */
+
+                        (H5PL_table_g[H5PL_table_used_g]).handle = handle;
+                        (H5PL_table_g[H5PL_table_used_g]).pl_type = pl_type;
+                        (H5PL_table_g[H5PL_table_used_g]).pl_id = plugin_info->id;
+                        H5PL_table_used_g++;
+
+                        /* Set the plugin info to return */
+                        *pl_info = (const void *)plugin_info;
+
+                        /* Indicate success */
+                        ret_value = TRUE;
+                    } /* end if */
+                    else
+                        if(H5PL__close(handle) < 0)
+                            HGOTO_ERROR(H5E_PLUGIN, H5E_CLOSEERROR, FAIL, "can't close dynamic library")
+
+                    break;
+                }
+            case H5PL_TYPE_VOL:
+                {
+                    const H5VL_class_t *plugin_info;
+
+                    /* Invoke H5PLget_plugin_info to verify this is the right library we are looking for.
+                     * Move on if it isn't.
+                     */
+                    if(NULL == (plugin_info = (const H5VL_class_t *)(*get_plugin_info)())) {
+                        if(H5PL__close(handle) < 0)
+                            HGOTO_ERROR(H5E_PLUGIN, H5E_CLOSEERROR, FAIL, "can't close dynamic library")
+                        HGOTO_ERROR(H5E_PLUGIN, H5E_CANTGET, FAIL, "can't get plugin info")
+                    } /* end if */
+
+                    /* Successfully found plugin library, check if it's the right one */
+                    if((pl_id > MAX_VOL_LIB_VALUE && plugin_info->value == pl_id) ||
+                       (pl_name && !strcmp(pl_name, plugin_info->name))) {
+                        /* Expand the table if it is too small */
+                        if(H5PL_vol_table_used_g >= H5PL_vol_table_alloc_g) {
+                            size_t n;
+                            H5PL_table_t *table = NULL;
+
+                            if(0 == H5PL_vol_table_alloc_g)
+                                n = 16;
+                            else
+                                n = 2 * H5PL_vol_table_alloc_g;
+
+                            table = (H5PL_table_t *)H5MM_realloc(H5PL_vol_table_g, n * sizeof(H5PL_table_t));
+                            if(!table)
+                                HGOTO_ERROR(H5E_RESOURCE, H5E_CANTALLOC, FAIL, "unable to extend dynamic library table for vol plugins")
+
+                            H5PL_vol_table_g = table;
+                            H5PL_vol_table_alloc_g = n;
+                        } /* end if */
+
+                        (H5PL_vol_table_g[H5PL_vol_table_used_g]).handle = handle;
+                        (H5PL_vol_table_g[H5PL_vol_table_used_g]).pl_type = pl_type;
+                        (H5PL_vol_table_g[H5PL_vol_table_used_g]).pl_id = plugin_info->value;
+                        (H5PL_vol_table_g[H5PL_vol_table_used_g]).pl_name = HDstrdup(pl_name);
+                        H5PL_vol_table_used_g++;
+
+                        /* Set the plugin info to return */
+                        *pl_info = (const void *)plugin_info;
+
+                        /* Indicate success */
+                        ret_value = TRUE;
+                    } /* end if */
+                    else
+                        if(H5PL__close(handle) < 0)
+                            HGOTO_ERROR(H5E_PLUGIN, H5E_CLOSEERROR, FAIL, "can't close dynamic library")
+
+                    break;
+                }
+            case H5PL_TYPE_ERROR:
+            case H5PL_TYPE_NONE:
+            default:
+                HGOTO_ERROR(H5E_PLUGIN, H5E_BADVALUE, FAIL, "invalid plugin type")
+            } /* end switch */
         } /* end if */
     } /* end else */
 
@@ -609,14 +689,14 @@ done:
  *-------------------------------------------------------------------------
  */
 static htri_t
-H5PL__search_table(H5PL_type_t plugin_type, int type_id, const void **info)
+H5PL__search_table(H5PL_type_t plugin_type, int type_id, const char *plugin_name, const void **info)
 {
     htri_t         ret_value = FALSE;
 
     FUNC_ENTER_STATIC
 
     /* Search in the table of already opened dynamic libraries */
-    if(H5PL_table_used_g > 0) {
+    if(H5PL_TYPE_FILTER == plugin_type && H5PL_table_used_g > 0) {
         size_t         i;
 
         for(i = 0; i < H5PL_table_used_g; i++) {
@@ -635,6 +715,26 @@ H5PL__search_table(H5PL_type_t plugin_type, int type_id, const void **info)
             } /* end if */
         } /* end for */
     } /* end if */
+    else if(H5PL_TYPE_VOL == plugin_type && H5PL_vol_table_used_g > 0) {
+        size_t         i;
+
+        for(i = 0; i < H5PL_vol_table_used_g; i++) {
+            if((plugin_type == (H5PL_vol_table_g[i]).pl_type) && 
+               (type_id == (H5PL_vol_table_g[i]).pl_id || !strcmp(plugin_name, (H5PL_vol_table_g[i]).pl_name))) {
+                H5PL_get_plugin_info_t get_plugin_info;
+                const H5VL_class_t   *plugin_info;
+
+                if(NULL == (get_plugin_info = (H5PL_get_plugin_info_t)H5PL_GET_LIB_FUNC((H5PL_vol_table_g[i]).handle, "H5PLget_plugin_info")))
+		    HGOTO_ERROR(H5E_DATATYPE, H5E_CANTGET, FAIL, "can't get function for H5PLget_plugin_info")
+
+	        if(NULL == (plugin_info = (const H5VL_class_t *)(*get_plugin_info)()))
+		    HGOTO_ERROR(H5E_DATATYPE, H5E_CANTGET, FAIL, "can't get plugin info")
+
+	        *info = plugin_info;
+                HGOTO_DONE(TRUE)
+            } /* end if */
+        } /* end for */
+    } /* end if */
 
 done:
     FUNC_LEAVE_NOAPI(ret_value)
diff --git a/src/H5PLextern.h b/src/H5PLextern.h
index 943e3aa..b5563e4 100644
--- a/src/H5PLextern.h
+++ b/src/H5PLextern.h
@@ -30,7 +30,8 @@
 typedef enum H5PL_type_t {
     H5PL_TYPE_ERROR        = -1,  /*error                    */
     H5PL_TYPE_FILTER       = 0,   /*filter                   */
-    H5PL_TYPE_NONE         = 1    /*this must be last!       */
+    H5PL_TYPE_VOL          = 1,   /*vol plugin               */
+    H5PL_TYPE_NONE         = 2    /*this must be last!       */
 } H5PL_type_t;
 
 
diff --git a/src/H5PLprivate.h b/src/H5PLprivate.h
index b117613..237408d 100644
--- a/src/H5PLprivate.h
+++ b/src/H5PLprivate.h
@@ -46,7 +46,7 @@
 /***************************************/
 
 /* Internal API routines */
-H5_DLL const void *H5PL_load(H5PL_type_t plugin_type, int type_id);
+H5_DLL const void *H5PL_load(H5PL_type_t plugin_type, int type_id, const char *plugin_name);
 H5_DLL htri_t H5PL_no_plugin(void);
 
 #endif /* _H5PLprivate_H */
diff --git a/src/H5Pocpl.c b/src/H5Pocpl.c
index 37beb90..94fb5b2 100644
--- a/src/H5Pocpl.c
+++ b/src/H5Pocpl.c
@@ -834,7 +834,7 @@ H5P__set_filter(H5P_genplist_t *plist, H5Z_filter_t filter, unsigned int flags,
     if(!filter_avail) {
         const H5Z_class2_t *filter_info;
 
-        if(NULL == (filter_info = (const H5Z_class2_t *)H5PL_load(H5PL_TYPE_FILTER, (int)filter)))
+        if(NULL == (filter_info = (const H5Z_class2_t *)H5PL_load(H5PL_TYPE_FILTER, (int)filter, NULL)))
             HGOTO_ERROR(H5E_PLINE, H5E_CANTLOAD, FAIL, "failed to load dynamically loaded plugin")
         if(H5Z_register(filter_info) < 0)
 	    HGOTO_ERROR(H5E_PLINE, H5E_CANTINIT, FAIL, "unable to register filter")
diff --git a/src/H5VL.c b/src/H5VL.c
index 65a8a8f..f1a39ee 100644
--- a/src/H5VL.c
+++ b/src/H5VL.c
@@ -40,6 +40,7 @@
 #include "H5Eprivate.h"		/* Error handling		  	*/
 #include "H5Iprivate.h"		/* IDs			  		*/
 #include "H5MMprivate.h"	/* Memory management			*/
+#include "H5PLprivate.h"        /* Plugins                              */
 #include "H5VLpkg.h"		/* VOL package header		  	*/
 #include "H5VLprivate.h"	/* VOL          		  	*/
 
@@ -205,6 +206,39 @@ H5VL_free_cls(H5VL_class_t *cls)
 
 
 /*-------------------------------------------------------------------------
+ * Function:	H5VL__get_plugin_cb
+ *
+ * Purpose:	Callback routine to search through registered VLs
+ *
+ * Return:	Success:	The first object in the type for which FUNC
+ *				returns non-zero. NULL if FUNC returned zero
+ *				for every object in the type.
+ *		Failure:	NULL
+ *
+ * Programmer:	Quincey Koziol
+ *		Friday, March 30, 2012
+ *
+ *-------------------------------------------------------------------------
+ */
+static int
+H5VL__get_plugin_cb(void *obj, hid_t id, void *_op_data)
+{
+    H5VL_get_plugin_ud_t *op_data = (H5VL_get_plugin_ud_t *)_op_data; /* User data for callback */
+    H5VL_class_t *cls = (H5VL_class_t *)obj;
+    int ret_value = H5_ITER_CONT;     /* Callback return value */
+
+    FUNC_ENTER_STATIC_NOERR
+
+    if(0 == strcmp(cls->name, op_data->name)) {
+        op_data->ret_id = id;
+        ret_value = H5_ITER_STOP;
+    }
+
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5VL__get_plugin_cb() */
+
+
+/*-------------------------------------------------------------------------
  * Function:	H5VLregister
  *
  * Purpose:	Registers a new vol plugin as a member of the virtual object
@@ -240,7 +274,7 @@ H5VLregister(const H5VL_class_t *cls)
     /* MSC - check if required callback are defined?? */
 
     /* Create the new class ID */
-    if((ret_value=H5VL_register(cls, sizeof(H5VL_class_t), TRUE)) < 0)
+    if((ret_value = H5VL_register(cls, sizeof(H5VL_class_t), TRUE)) < 0)
         HGOTO_ERROR(H5E_ATOM, H5E_CANTREGISTER, FAIL, "unable to register vol plugin ID")
 
 done:
@@ -249,6 +283,66 @@ done:
 
 
 /*-------------------------------------------------------------------------
+ * Function:	H5VLregister_by_name
+ *
+ * Purpose:	Registers a new vol plugin as a member of the virtual object
+ *		layer class.
+ *
+ * Return:	Success:	A vol plugin ID which is good until the
+ *				library is closed or the plugin is
+ *				unregistered.
+ *
+ *		Failure:	A negative value.
+ *
+ * Programmer:	Mohamad Chaarawi
+ *              September, 2014
+ *
+ *-------------------------------------------------------------------------
+ */
+hid_t
+H5VLregister_by_name(const char *name)
+{
+    H5VL_get_plugin_ud_t op_data;
+    hid_t ret_value;
+
+    FUNC_ENTER_API(FAIL)
+    H5TRACE1("i", "*s", name);
+
+    /* Check arguments */
+    if(!name)
+	HGOTO_ERROR(H5E_ARGS, H5E_UNINITIALIZED, FAIL, "null plugin name is disallowed")
+
+    op_data.ret_id = FAIL;
+    op_data.name = name;
+
+    /* check if plugin is already registered */
+    if(H5I_iterate(H5I_VOL, H5VL__get_plugin_cb, &op_data, TRUE) < 0)
+        HGOTO_ERROR(H5E_VOL, H5E_BADITER,FAIL, "can't iterate over VOL ids")
+
+    if(op_data.ret_id != FAIL) {
+        /* If plugin alread registered, increment ref count on ID and return ID */
+        if(H5I_inc_ref(op_data.ret_id, TRUE) < 0)
+            HGOTO_ERROR(H5E_VOL, H5E_CANTINC, FAIL, "unable to increment ref count on VOL plugin")
+        ret_value = op_data.ret_id;
+    }
+    else {
+        const H5VL_class_t *cls;
+
+        /* Try loading the plugin */
+        if(NULL == (cls = (const H5VL_class_t *)H5PL_load(H5PL_TYPE_VOL, -1, name)))
+            HGOTO_ERROR(H5E_VOL, H5E_CANTINIT, FAIL, "unable to load VOL plugin")
+
+        /* Register the plugin we loaded */
+        if((ret_value = H5VL_register(cls, sizeof(H5VL_class_t), TRUE)) < 0)
+            HGOTO_ERROR(H5E_ATOM, H5E_CANTREGISTER, FAIL, "unable to register vol plugin ID")
+    }
+
+done:
+    FUNC_LEAVE_API(ret_value)
+} /* end H5VLregister() */
+
+
+/*-------------------------------------------------------------------------
  * Function:	H5VLunregister
  *
  * Purpose:	Removes a vol plugin ID from the library. This in no way affects
@@ -353,39 +447,6 @@ done:
 
 
 /*-------------------------------------------------------------------------
- * Function:	H5VL__is_registered_cb
- *
- * Purpose:	Callback routine to search through registered VLs
- *
- * Return:	Success:	The first object in the type for which FUNC
- *				returns non-zero. NULL if FUNC returned zero
- *				for every object in the type.
- *		Failure:	NULL
- *
- * Programmer:	Quincey Koziol
- *		Friday, March 30, 2012
- *
- *-------------------------------------------------------------------------
- */
-static int
-H5VL__get_plugin_cb(void *obj, hid_t id, void *_op_data)
-{
-    H5VL_get_plugin_ud_t *op_data = (H5VL_get_plugin_ud_t *)_op_data; /* User data for callback */
-    H5VL_class_t *cls = (H5VL_class_t *)obj;
-    int ret_value = H5_ITER_CONT;     /* Callback return value */
-
-    FUNC_ENTER_STATIC_NOERR
-
-    if(0 == strcmp(cls->name, op_data->name)) {
-        op_data->ret_id = id;
-        ret_value = H5_ITER_STOP;
-    }
-
-    FUNC_LEAVE_NOAPI(ret_value)
-} /* end H5VL__get_plugin_cb() */
-
-
-/*-------------------------------------------------------------------------
  * Function:	H5VLis_registered
  *
  * Purpose:	Tests whether a VOL class has been registered or not
diff --git a/src/H5VLpublic.h b/src/H5VLpublic.h
index 35c4c46..bf3517c 100644
--- a/src/H5VLpublic.h
+++ b/src/H5VLpublic.h
@@ -420,13 +420,13 @@ H5_DLL herr_t H5VLterminate(hid_t plugin_id, hid_t vtpl_id);
 H5_DLL hid_t H5VLget_plugin_id(const char *name);
 H5_DLL herr_t H5VLclose(hid_t plugin_id);
 H5_DLL hid_t H5VLregister(const H5VL_class_t *cls);
+H5_DLL hid_t H5VLregister_by_name(const char *plugin_name);
 H5_DLL herr_t H5VLunregister(hid_t plugin_id);
 H5_DLL htri_t H5VLis_registered(const char *name);
 H5_DLL ssize_t H5VLget_plugin_name(hid_t id, char *name/*out*/, size_t size);
 H5_DLL hid_t H5VLobject_register(void *obj, H5I_type_t obj_type, hid_t plugin_id);
 H5_DLL herr_t H5VLget_object(hid_t obj_id, void **obj);
 #if 0
-H5_DLL hid_t H5VLregister_by_name(const char *plugin_name);
 H5_DLL herr_t H5VLioctl(hid_t loc_id or vol_id, <class enum>, ...);
 #endif
 
diff --git a/src/H5Z.c b/src/H5Z.c
index f1a385a..bc5f290 100644
--- a/src/H5Z.c
+++ b/src/H5Z.c
@@ -668,8 +668,8 @@ H5Zfilter_avail(H5Z_filter_t id)
     else if(ret_value == FALSE) {
         const H5Z_class2_t *filter_info;
 
-        if(NULL != (filter_info = (const H5Z_class2_t *)H5PL_load(H5PL_TYPE_FILTER, (int)id)))
-        	ret_value = TRUE;
+    if(NULL != (filter_info = (const H5Z_class2_t *)H5PL_load(H5PL_TYPE_FILTER, (int)id, NULL)))
+        ret_value = TRUE;
     } /* end if */
 
 done:
@@ -1330,20 +1330,20 @@ H5Z_pipeline(const H5O_pline_t *pline, unsigned flags,
              */
 	    if((fclass_idx = H5Z_find_idx(pline->filter[idx].id)) < 0) {
                 hbool_t issue_error = FALSE;
-				const H5Z_class2_t    *filter_info;
-
-				/* Try loading the filter */
-				if(NULL != (filter_info = (const H5Z_class2_t *)H5PL_load(H5PL_TYPE_FILTER, (int)(pline->filter[idx].id)))) {
-					/* Register the filter we loaded */
-					if(H5Z_register(filter_info) < 0)
-						HGOTO_ERROR(H5E_PLINE, H5E_CANTINIT, FAIL, "unable to register filter")
-
-					/* Search in the table of registered filters again to find the dynamic filter just loaded and registered */
-					if((fclass_idx = H5Z_find_idx(pline->filter[idx].id)) < 0)
-						issue_error = TRUE;
-				} /* end if */
-				else
-					issue_error = TRUE;
+                const H5Z_class2_t    *filter_info;
+
+                /* Try loading the filter */
+                if(NULL != (filter_info = (const H5Z_class2_t *)H5PL_load(H5PL_TYPE_FILTER, (int)(pline->filter[idx].id), NULL))) {
+                    /* Register the filter we loaded */
+                    if(H5Z_register(filter_info) < 0)
+                        HGOTO_ERROR(H5E_PLINE, H5E_CANTINIT, FAIL, "unable to register filter")
+
+                    /* Search in the table of registered filters again to find the dynamic filter just loaded and registered */
+                    if((fclass_idx = H5Z_find_idx(pline->filter[idx].id)) < 0)
+                        issue_error = TRUE;
+                } /* end if */
+                else
+                    issue_error = TRUE;
 
                 /* Check for error */
                 if(issue_error) {