Switch switch remainder of API routines to use VOL callbacks.

25 files changed, 462 insertions, 561 deletions

diff --git a/bin/trace b/bin/trace
index fa7090b..f665d9d 100755
--- a/bin/trace
+++ b/bin/trace
@@ -68,6 +68,7 @@ $Source = "";
                "unsigned"                   => "Iu",
                "unsigned int"               => "Iu",
                "uint32_t"                   => "Iu",
+               "uint64_t"                   => "UL",
                "H5I_type_t"                 => "It",
                "H5G_link_t"                 => "Ll", #Same as H5L_type_t now
                "H5L_type_t"                 => "Ll",
@@ -111,6 +112,7 @@ $Source = "";
                "H5VL_link_specific_t"       => "Vm",
                "H5VL_object_get_t"          => "Vn",
                "H5VL_object_specific_t"     => "Vo",
+               "H5VL_request_specific_t"    => "Vr",
                "void"                       => "x",
                "FILE"                       => "x",
                "H5A_operator_t"             => "x",
diff --git a/src/H5Adeprec.c b/src/H5Adeprec.c
index bf97a25..af3ab4d 100644
--- a/src/H5Adeprec.c
+++ b/src/H5Adeprec.c
@@ -115,7 +115,7 @@ H5Acreate1(hid_t loc_id, const char *name, hid_t type_id, hid_t space_id,
 	  hid_t acpl_id)
 {
     void    *attr = NULL;       /* attr token from VOL connector */
-    H5VL_object_t    *vol_obj = NULL;        /* object token of loc_id */
+    H5VL_object_t  *vol_obj = NULL;     /* Object token of loc_id */
     H5VL_loc_params_t   loc_params;
     H5P_genplist_t      *plist;            /* Property list pointer */
     hid_t		ret_value = H5I_INVALID_HID;              /* Return value */
@@ -199,7 +199,7 @@ hid_t
 H5Aopen_name(hid_t loc_id, const char *name)
 {
     void    *attr = NULL;       /* attr token from VOL connector */
-    H5VL_object_t    *vol_obj = NULL;        /* object token of loc_id */
+    H5VL_object_t  *vol_obj = NULL;     /* Object token of loc_id */
     H5VL_loc_params_t loc_params; 
     hid_t		ret_value = H5I_INVALID_HID;              /* Return value */
 
@@ -264,7 +264,7 @@ hid_t
 H5Aopen_idx(hid_t loc_id, unsigned idx)
 {
     void    *attr = NULL;       /* attr token from VOL connector */
-    H5VL_object_t    *vol_obj = NULL;        /* object token of loc_id */
+    H5VL_object_t  *vol_obj = NULL;     /* Object token of loc_id */
     H5VL_loc_params_t   loc_params;
     hid_t		ret_value = H5I_INVALID_HID;              /* Return value */
 
@@ -327,7 +327,7 @@ done:
 int
 H5Aget_num_attrs(hid_t loc_id)
 {
-    H5VL_object_t      *vol_obj;
+    H5VL_object_t  *vol_obj = NULL;     /* Object token of loc_id */
     H5VL_loc_params_t   loc_params;
     H5O_info_t          oinfo;
     int                 ret_value = -1;
@@ -338,7 +338,7 @@ H5Aget_num_attrs(hid_t loc_id)
     loc_params.type     = H5VL_OBJECT_BY_SELF;
     loc_params.obj_type = H5I_get_type(loc_id);
 
-    /* get the location object */
+    /* Get the location object */
     if(NULL == (vol_obj = H5VL_vol_object(loc_id)))
         HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, (-1), "invalid location identifier")
 
@@ -393,18 +393,23 @@ done:
 herr_t
 H5Aiterate1(hid_t loc_id, unsigned *attr_num, H5A_operator1_t op, void *op_data)
 {
-    herr_t	    ret_value;      /* Return value */
+    H5VL_object_t  *vol_obj = NULL;     /* Object token of loc_id */
+    herr_t	    ret_value;          /* Return value */
 
-    FUNC_ENTER_API(FAIL)
+    FUNC_ENTER_API(H5_ITER_ERROR)
     H5TRACE4("e", "i*Iux*x", loc_id, attr_num, op, op_data);
 
     /* check arguments */
     if(H5I_ATTR == H5I_get_type(loc_id))
-        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "location is not valid for an attribute")
+        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, H5_ITER_ERROR, "location is not valid for an attribute")
+
+    /* Get the location object */
+    if(NULL == (vol_obj = H5VL_vol_object(loc_id)))
+        HGOTO_ERROR(H5E_VOL, H5E_BADTYPE, H5_ITER_ERROR, "invalid location identifier")
 
     /* Call attribute iteration routine */
-    if((ret_value = H5A__iterate_old(loc_id, attr_num, op, op_data)) < 0)
-        HERROR(H5E_ATTR, H5E_BADITER, "error iterating over attributes");
+    if((ret_value = H5VL_attr_optional(vol_obj, H5P_DATASET_XFER_DEFAULT, H5_REQUEST_NULL, H5VL_ATTR_ITERATE_OLD, loc_id, attr_num, op, op_data)) < 0)
+        HERROR(H5E_VOL, H5E_BADITER, "error iterating over attributes");
 
 done:
     FUNC_LEAVE_API(ret_value)
diff --git a/src/H5Aint.c b/src/H5Aint.c
index f8efd26..6502fa4 100644
--- a/src/H5Aint.c
+++ b/src/H5Aint.c
@@ -2659,7 +2659,7 @@ done:
     if(obj_loc_id != H5I_INVALID_HID) {
         if(H5I_dec_app_ref(obj_loc_id) < 0)
             HDONE_ERROR(H5E_ATTR, H5E_CANTDEC, FAIL, "unable to close temporary object");
-    }
+    } /* end if */
     else if(loc_found && H5G_loc_free(&obj_loc) < 0)
         HDONE_ERROR(H5E_ATTR, H5E_CANTRELEASE, FAIL, "can't free location");
 
@@ -2688,7 +2688,7 @@ H5A__iterate_old(hid_t loc_id, unsigned *attr_num, H5A_operator1_t op,
     hsize_t idx;                        /* Index of attribute to start iterating at */
     herr_t ret_value = SUCCEED;         /* Return value */
 
-    FUNC_ENTER_PACKAGE
+    FUNC_ENTER_PACKAGE_NOERR
 
     /* Build attribute operator info */
     attr_op.op_type = H5A_ATTR_OP_APP;
@@ -2699,13 +2699,12 @@ H5A__iterate_old(hid_t loc_id, unsigned *attr_num, H5A_operator1_t op,
 
     /* Call internal attribute iteration routine */
     if((ret_value = H5A__iterate_common(loc_id, H5_INDEX_CRT_ORDER, H5_ITER_INC, &idx, &attr_op, op_data)) < 0)
-        HGOTO_ERROR(H5E_ATTR, H5E_BADITER, FAIL, "error iterating over attributes")
+        HERROR(H5E_ATTR, H5E_BADITER, "error iterating over attributes");
 
     /* Translate hsize_t index value to legacy unsigned index value*/
     if(attr_num)
         *attr_num = (unsigned)idx;
 
-done:
     FUNC_LEAVE_NOAPI(ret_value)
 } /* H5A__iterate_old() */
 #endif /* H5_NO_DEPRECATED_SYMBOLS */
diff --git a/src/H5Apkg.h b/src/H5Apkg.h
index 91061cd..12e0857 100644
--- a/src/H5Apkg.h
+++ b/src/H5Apkg.h
@@ -155,6 +155,13 @@ typedef struct {
     H5A_t       **attrs;        /* Pointer to array of attribute pointers */
 } H5A_attr_table_t;
 
+/* Types for optional attribute VOL operations */
+typedef enum H5VL_attr_optional_t {
+#ifndef H5_NO_DEPRECATED_SYMBOLS
+    H5VL_ATTR_ITERATE_OLD               /* H5Aiterate (deprecated routine) */
+#endif /* H5_NO_DEPRECATED_SYMBOLS */
+} H5VL_attr_optional_t;
+
 
 /*****************************/
 /* Package Private Variables */
diff --git a/src/H5Dint.c b/src/H5Dint.c
index d5ac251..6bb3343 100644
--- a/src/H5Dint.c
+++ b/src/H5Dint.c
@@ -1966,7 +1966,7 @@ H5D_nameof(const H5D_t *dataset)
     /* Use FUNC_ENTER_NOAPI_NOINIT_NOERR here to avoid performance issues */
     FUNC_ENTER_NOAPI_NOINIT_NOERR
 
-    FUNC_LEAVE_NOAPI(dataset ? &(dataset->path) : (H5G_name_t *)NULL)
+    FUNC_LEAVE_NOAPI(dataset ? (H5G_name_t *)&(dataset->path) : (H5G_name_t *)NULL)
 } /* end H5D_nameof() */
 
 
diff --git a/src/H5Dpkg.h b/src/H5Dpkg.h
index c84c245..30652a5 100644
--- a/src/H5Dpkg.h
+++ b/src/H5Dpkg.h
@@ -110,7 +110,7 @@ typedef struct H5D_type_info_t {
     hbool_t  bkg_buf_allocated;          /* Whether the background buffer was allocated */
 } H5D_type_info_t;
 
-/* types for dataset optional VOL operations */
+/* Types for dataset optional VOL operations */
 typedef enum H5VL_dataset_optional_t {
     H5VL_DATASET_FORMAT_CONVERT,            /* H5Dformat_convert (internal) */
     H5VL_DATASET_GET_CHUNK_INDEX_TYPE,      /* H5Dget_chunk_index_type      */
diff --git a/src/H5G.c b/src/H5G.c
index 0beee14..114f3bf 100644
--- a/src/H5G.c
+++ b/src/H5G.c
@@ -351,13 +351,13 @@ H5Gcreate2(hid_t loc_id, const char *name, hid_t lcpl_id, hid_t gcpl_id,
         HGOTO_ERROR(H5E_SYM, H5E_CANTSET, H5I_INVALID_HID, "can't set access property list info")
 
     /* Get the gcpl structure and set the link properties on it */
-    if (NULL == (plist = (H5P_genplist_t *)H5I_object(gcpl_id)))
+    if(NULL == (plist = (H5P_genplist_t *)H5I_object(gcpl_id)))
         HGOTO_ERROR(H5E_ATOM, H5E_BADATOM, H5I_INVALID_HID, "can't find object for ID")
-    if (H5P_set(plist, H5VL_PROP_GRP_LCPL_ID, &lcpl_id) < 0)
+    if(H5P_set(plist, H5VL_PROP_GRP_LCPL_ID, &lcpl_id) < 0)
         HGOTO_ERROR(H5E_PLIST, H5E_CANTSET, H5I_INVALID_HID, "can't set property value for lcpl id")
 
-    /* get the location object */
-    if (NULL == (vol_obj = (H5VL_object_t *)H5I_object(loc_id)))
+    /* Get the location object */
+    if(NULL == (vol_obj = (H5VL_object_t *)H5I_object(loc_id)))
         HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, H5I_INVALID_HID, "invalid location identifier")
 
     /* Set the location parameters */
@@ -439,7 +439,7 @@ H5Gcreate_anon(hid_t loc_id, hid_t gcpl_id, hid_t gapl_id)
     loc_params.type         = H5VL_OBJECT_BY_SELF;
     loc_params.obj_type     = H5I_get_type(loc_id);
 
-    /* get the location object */
+    /* Get the location object */
     if(NULL == (vol_obj = (H5VL_object_t *)H5I_object(loc_id)))
         HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, H5I_INVALID_HID, "invalid location identifier")
 
@@ -590,7 +590,7 @@ H5Gget_info(hid_t loc_id, H5G_info_t *group_info)
     /* Retrieve the group's information */
     loc_params.type     = H5VL_OBJECT_BY_SELF;
     loc_params.obj_type = id_type;
-    if((ret_value = H5VL_group_get(vol_obj, H5VL_GROUP_GET_INFO, H5P_DATASET_XFER_DEFAULT, H5_REQUEST_NULL, loc_params, group_info)) < 0)
+    if(H5VL_group_get(vol_obj, H5VL_GROUP_GET_INFO, H5P_DATASET_XFER_DEFAULT, H5_REQUEST_NULL, loc_params, group_info) < 0)
         HGOTO_ERROR(H5E_SYM, H5E_CANTGET, FAIL, "unable to get group info")
 
 done:
@@ -632,7 +632,7 @@ H5Gget_info_by_name(hid_t loc_id, const char *name, H5G_info_t *group_info,
         HGOTO_ERROR(H5E_SYM, H5E_CANTSET, FAIL, "can't set access property list info")
 
     /* Get the location object */
-    if (NULL == (vol_obj = (H5VL_object_t *)H5I_object(loc_id)))
+    if(NULL == (vol_obj = (H5VL_object_t *)H5I_object(loc_id)))
         HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "invalid location identifier")
 
     /* Set up location parameters */
@@ -642,7 +642,7 @@ H5Gget_info_by_name(hid_t loc_id, const char *name, H5G_info_t *group_info,
     loc_params.obj_type                         = H5I_get_type(loc_id);
 
     /* Retrieve the group's information */
-    if((ret_value = H5VL_group_get(vol_obj, H5VL_GROUP_GET_INFO, H5P_DATASET_XFER_DEFAULT, H5_REQUEST_NULL, loc_params, group_info)) < 0)
+    if(H5VL_group_get(vol_obj, H5VL_GROUP_GET_INFO, H5P_DATASET_XFER_DEFAULT, H5_REQUEST_NULL, loc_params, group_info) < 0)
         HGOTO_ERROR(H5E_SYM, H5E_CANTGET, FAIL, "can't retrieve group info")
 
 done:
@@ -688,7 +688,7 @@ H5Gget_info_by_idx(hid_t loc_id, const char *group_name, H5_index_t idx_type,
     if(H5CX_set_apl(&lapl_id, H5P_CLS_LACC, loc_id, FALSE) < 0)
         HGOTO_ERROR(H5E_SYM, H5E_CANTSET, FAIL, "can't set access property list info")
 
-    /* get the location object */
+    /* Get the location object */
     if(NULL == (vol_obj = (H5VL_object_t *)H5I_object(loc_id)))
         HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "invalid location identifier")
 
@@ -702,7 +702,7 @@ H5Gget_info_by_idx(hid_t loc_id, const char *group_name, H5_index_t idx_type,
     loc_params.obj_type                     = H5I_get_type(loc_id);
 
     /* Retrieve the group's information */
-    if((ret_value = H5VL_group_get(vol_obj, H5VL_GROUP_GET_INFO, H5P_DATASET_XFER_DEFAULT, H5_REQUEST_NULL, loc_params, group_info)) < 0)
+    if(H5VL_group_get(vol_obj, H5VL_GROUP_GET_INFO, H5P_DATASET_XFER_DEFAULT, H5_REQUEST_NULL, loc_params, group_info) < 0)
         HGOTO_ERROR(H5E_SYM, H5E_CANTGET, FAIL, "can't retrieve group info")
 
 done:
diff --git a/src/H5Gcompact.c b/src/H5Gcompact.c
index b32ce39..7e2b324 100644
--- a/src/H5Gcompact.c
+++ b/src/H5Gcompact.c
@@ -572,71 +572,3 @@ done:
     FUNC_LEAVE_NOAPI(ret_value)
 } /* end H5G__compact_lookup_by_idx() */
 
-#ifndef H5_NO_DEPRECATED_SYMBOLS
-
-/*-------------------------------------------------------------------------
- * Function:	H5G__compact_get_type_by_idx
- *
- * Purpose:     Returns the type of objects in the group by giving index.
- *
- * Return:	Success:        Non-negative
- *		Failure:	Negative
- *
- * Programmer:	Quincey Koziol
- *	        Sep 12, 2005
- *
- *-------------------------------------------------------------------------
- */
-H5G_obj_t
-H5G__compact_get_type_by_idx(H5O_loc_t *oloc, const H5O_linfo_t *linfo,
-    hsize_t idx)
-{
-    H5G_link_table_t    ltable = {0, NULL};         /* Link table */
-    H5G_obj_t		ret_value = H5G_UNKNOWN;    /* Return value */
-
-    FUNC_ENTER_PACKAGE
-
-    /* Sanity check */
-    HDassert(oloc);
-
-    /* Build table of all link messages */
-    if(H5G__compact_build_table(oloc, linfo, H5_INDEX_NAME, H5_ITER_INC, &ltable) < 0)
-        HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, H5G_UNKNOWN, "can't create link message table")
-
-    /* Check for going out of bounds */
-    if(idx >= ltable.nlinks)
-        HGOTO_ERROR(H5E_ARGS, H5E_BADRANGE, H5G_UNKNOWN, "index out of bound")
-
-    /* Determine type of object */
-    if(ltable.lnks[idx].type == H5L_TYPE_SOFT)
-        ret_value = H5G_LINK;
-    else if(ltable.lnks[idx].type >= H5L_TYPE_UD_MIN)
-        ret_value = H5G_UDLINK;
-    else if(ltable.lnks[idx].type == H5L_TYPE_HARD){
-        H5O_loc_t tmp_oloc;             /* Temporary object location */
-        H5O_type_t obj_type;            /* Type of object at location */
-
-        /* Build temporary object location */
-        tmp_oloc.file = oloc->file;
-        tmp_oloc.addr = ltable.lnks[idx].u.hard.addr;
-
-        /* Get the type of the object */
-        if(H5O_obj_type(&tmp_oloc, &obj_type) < 0)
-            HGOTO_ERROR(H5E_SYM, H5E_CANTGET, H5G_UNKNOWN, "can't get object type")
-
-        /* Map to group object type */
-        if(H5G_UNKNOWN == (ret_value = H5G_map_obj_type(obj_type)))
-            HGOTO_ERROR(H5E_SYM, H5E_BADTYPE, H5G_UNKNOWN, "can't determine object type")
-    } else {
-        HGOTO_ERROR(H5E_SYM, H5E_BADTYPE, H5G_UNKNOWN, "unknown link type")
-    } /* end else */
-
-done:
-    /* Release link table */
-    if(ltable.lnks && H5G__link_release_table(&ltable) < 0)
-        HDONE_ERROR(H5E_SYM, H5E_CANTFREE, H5G_UNKNOWN, "unable to release link table")
-
-    FUNC_LEAVE_NOAPI(ret_value)
-} /* end H5G__compact_get_type_by_idx() */
-#endif /* H5_NO_DEPRECATED_SYMBOLS */
-
diff --git a/src/H5Gdense.c b/src/H5Gdense.c
index d2bcad1..a2ef55c 100644
--- a/src/H5Gdense.c
+++ b/src/H5Gdense.c
@@ -1777,80 +1777,3 @@ done:
     FUNC_LEAVE_NOAPI(ret_value)
 } /* end H5G__dense_delete() */
 
-#ifndef H5_NO_DEPRECATED_SYMBOLS
-
-/*-------------------------------------------------------------------------
- * Function:	H5G__dense_get_type_by_idx
- *
- * Purpose:     Returns the type of objects in the group by giving index.
- *
- * Note:	This routine assumes a lookup on the link name index in
- *		increasing order and isn't currently set up to be as
- *		flexible as other routines in this code module, because
- *		the H5Gget_objtype_by_idx that it's supporting is
- *		deprecated.
- *
- * Return:	Success:        Non-negative, object type
- *		Failure:	Negative
- *
- * Programmer:	Quincey Koziol
- *		koziol@hdfgroup.org
- *		Sep 19 2006
- *
- *-------------------------------------------------------------------------
- */
-H5G_obj_t
-H5G__dense_get_type_by_idx(H5F_t *f, H5O_linfo_t *linfo, hsize_t idx)
-{
-    H5G_link_table_t ltable = {0, NULL};        /* Table of links */
-    H5G_obj_t ret_value = H5G_UNKNOWN;          /* Return value */
-
-    FUNC_ENTER_PACKAGE
-
-    /*
-     * Check arguments.
-     */
-    HDassert(f);
-    HDassert(linfo);
-
-    /* Build the table of links for this group */
-    if(H5G__dense_build_table(f, linfo, H5_INDEX_NAME, H5_ITER_INC, &ltable) < 0)
-        HGOTO_ERROR(H5E_SYM, H5E_CANTGET, H5G_UNKNOWN, "error building table of links")
-
-    /* Check for going out of bounds */
-    if(idx >= ltable.nlinks)
-        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, H5G_UNKNOWN, "index out of bound")
-
-    /* Determine type of object */
-    if(ltable.lnks[idx].type == H5L_TYPE_SOFT)
-        ret_value = H5G_LINK;
-    else if(ltable.lnks[idx].type >= H5L_TYPE_UD_MIN)
-        ret_value = H5G_UDLINK;
-    else if(ltable.lnks[idx].type == H5L_TYPE_HARD) {
-        H5O_loc_t tmp_oloc;             /* Temporary object location */
-        H5O_type_t obj_type;            /* Type of object at location */
-
-        /* Build temporary object location */
-        tmp_oloc.file = f;
-        tmp_oloc.addr = ltable.lnks[idx].u.hard.addr;
-
-        /* Get the type of the object */
-        if(H5O_obj_type(&tmp_oloc, &obj_type) < 0)
-            HGOTO_ERROR(H5E_SYM, H5E_CANTGET, H5G_UNKNOWN, "can't get object type")
-
-        /* Map to group object type */
-        if(H5G_UNKNOWN == (ret_value = H5G_map_obj_type(obj_type)))
-            HGOTO_ERROR(H5E_SYM, H5E_BADTYPE, H5G_UNKNOWN, "can't determine object type")
-    } else {
-        HGOTO_ERROR(H5E_SYM, H5E_BADTYPE, H5G_UNKNOWN, "unknown link type")
-    } /* end else */
-
-done:
-    /* Release link table */
-    if(ltable.lnks && H5G__link_release_table(&ltable) < 0)
-        HDONE_ERROR(H5E_SYM, H5E_CANTFREE, H5G_UNKNOWN, "unable to release link table")
-
-    FUNC_LEAVE_NOAPI(ret_value)
-} /* end H5G__dense_get_type_by_idx() */
-#endif /* H5_NO_DEPRECATED_SYMBOLS */
-
diff --git a/src/H5Gdeprec.c b/src/H5Gdeprec.c
index 8aae2a1..6ed5344 100644
--- a/src/H5Gdeprec.c
+++ b/src/H5Gdeprec.c
@@ -72,13 +72,9 @@ typedef struct {
 /********************/
 /* Local Prototypes */
 /********************/
-
 static herr_t H5G__get_objinfo_cb(H5G_loc_t *grp_loc/*in*/, const char *name,
     const H5O_link_t *lnk, H5G_loc_t *obj_loc, void *_udata/*in,out*/,
     H5G_own_loc_t *own_loc/*out*/);
-static herr_t H5G__get_objinfo(const H5G_loc_t *loc, const char *name,
-    hbool_t follow_link, H5G_stat_t *statbuf/*out*/);
-static H5G_obj_t H5G__obj_get_type_by_idx(H5O_loc_t *oloc, hsize_t idx);
 #endif /* H5_NO_DEPRECATED_SYMBOLS */
 
 
@@ -172,7 +168,7 @@ hid_t
 H5Gcreate1(hid_t loc_id, const char *name, size_t size_hint)
 {
     void *grp = NULL;                   /* New group created */
-    H5VL_object_t *vol_obj = NULL;          /* object token of loc_id */
+    H5VL_object_t *vol_obj;             /* Object token of loc_id */
     H5VL_loc_params_t loc_params;
     H5P_genplist_t *plist;              /* Property list pointer */
     hid_t tmp_gcpl = H5I_INVALID_HID;               /* Temporary group creation property list */
@@ -227,6 +223,7 @@ H5Gcreate1(hid_t loc_id, const char *name, size_t size_hint)
     if(H5P_set(plist, H5VL_PROP_GRP_LCPL_ID, &lcpl_id) < 0)
         HGOTO_ERROR(H5E_PLIST, H5E_CANTGET, H5I_INVALID_HID, "can't get property value for lcpl id")
 
+    /* Set location parameters */
     loc_params.type         = H5VL_OBJECT_BY_SELF;
     loc_params.obj_type     = H5I_get_type(loc_id);
 
@@ -275,10 +272,10 @@ done:
 hid_t
 H5Gopen1(hid_t loc_id, const char *name)
 {
-    void *grp = NULL;                               /* Group opened */
-    H5VL_object_t *vol_obj = NULL;          /* object token of loc_id */
+    void *grp = NULL;                   /* Group opened */
+    H5VL_object_t *vol_obj = NULL;      /* Object token of loc_id */
     H5VL_loc_params_t loc_params;
-    hid_t       ret_value = H5I_INVALID_HID;        /* Return value */
+    hid_t ret_value = H5I_INVALID_HID;  /* Return value */
 
     FUNC_ENTER_API(H5I_INVALID_HID)
     H5TRACE2("i", "i*s", loc_id, name);
@@ -346,7 +343,7 @@ H5Glink(hid_t cur_loc_id, H5G_link_t type, const char *cur_name, const char *new
 
     /* Create link */
     if(type == H5L_TYPE_HARD) {
-        H5VL_object_t    *vol_obj = NULL;        /* object token of loc_id */
+        H5VL_object_t *vol_obj;                     /* Object token of loc_id */
         H5VL_loc_params_t loc_params1;
         H5VL_loc_params_t loc_params2;
         H5VL_object_t       tmp_vol_obj;            /* Temporary object token of */
@@ -379,7 +376,7 @@ H5Glink(hid_t cur_loc_id, H5G_link_t type, const char *cur_name, const char *new
             HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "unable to create link")
     } /* end if */
     else if(type == H5L_TYPE_SOFT) {
-        H5VL_object_t    *vol_obj = NULL;        /* object token of loc_id */
+        H5VL_object_t *vol_obj;                     /* Object token of loc_id */
         H5VL_loc_params_t loc_params;
 
         loc_params.type = H5VL_OBJECT_BY_NAME;
@@ -442,8 +439,8 @@ H5Glink2(hid_t cur_loc_id, const char *cur_name, H5G_link_t type,
 
     /* Create the appropriate kind of link */
     if(type == H5L_TYPE_HARD) {
-        H5VL_object_t    *vol_obj1 = NULL;        /* object token of loc_id */
-        H5VL_object_t    *vol_obj2 = NULL;        /* object token of loc_id */
+        H5VL_object_t *vol_obj1;                /* Object token of loc_id */
+        H5VL_object_t *vol_obj2;                /* Object token of loc_id */
         H5VL_loc_params_t loc_params1;
         H5VL_loc_params_t loc_params2;
 
@@ -474,7 +471,7 @@ H5Glink2(hid_t cur_loc_id, const char *cur_name, H5G_link_t type,
             HGOTO_ERROR(H5E_SYM, H5E_CANTINIT, FAIL, "unable to create link")
     } /* end if */
     else if(type == H5L_TYPE_SOFT) {
-        H5VL_object_t    *vol_obj = NULL;        /* object token of loc_id */
+        H5VL_object_t *vol_obj;                     /* Object token of loc_id */
         H5VL_loc_params_t loc_params;
 
         /* Soft links only need one location, the new_loc_id, but it's possible that
@@ -517,10 +514,10 @@ done:
 herr_t
 H5Gmove(hid_t src_loc_id, const char *src_name, const char *dst_name)
 {
-    H5VL_object_t    *vol_obj = NULL;        /* object token of loc_id */
+    H5VL_object_t *vol_obj;             /* Object token of loc_id */
     H5VL_loc_params_t loc_params1;
     H5VL_loc_params_t loc_params2;
-    herr_t      ret_value = SUCCEED;       /* Return value */
+    herr_t      ret_value = SUCCEED;    /* Return value */
 
     FUNC_ENTER_API(FAIL)
     H5TRACE3("e", "i*s*s", src_loc_id, src_name, dst_name);
@@ -562,9 +559,9 @@ herr_t
 H5Gmove2(hid_t src_loc_id, const char *src_name, hid_t dst_loc_id,
     const char *dst_name)
 {
-    H5VL_object_t    *vol_obj1 = NULL;        /* object token of src_id */
+    H5VL_object_t *vol_obj1 = NULL;        /* Object token of src_id */
     H5VL_loc_params_t loc_params1;
-    H5VL_object_t    *vol_obj2 = NULL;        /* object token of dst_id */
+    H5VL_object_t *vol_obj2 = NULL;        /* Object token of dst_id */
     H5VL_loc_params_t loc_params2;
     herr_t      ret_value = SUCCEED;       /* Return value */
 
@@ -615,7 +612,7 @@ done:
 herr_t
 H5Gunlink(hid_t loc_id, const char *name)
 {
-    H5VL_object_t    *vol_obj = NULL;        /* object token of loc_id */
+    H5VL_object_t *vol_obj;             /* Object token of loc_id */
     H5VL_loc_params_t loc_params;
     herr_t ret_value = SUCCEED;         /* Return value */
 
@@ -659,7 +656,7 @@ done:
 herr_t
 H5Gget_linkval(hid_t loc_id, const char *name, size_t size, char *buf/*out*/)
 {
-    H5VL_object_t    *vol_obj = NULL;        /* object token of loc_id */
+    H5VL_object_t *vol_obj;             /* Object token of loc_id */
     H5VL_loc_params_t loc_params;
     herr_t ret_value = SUCCEED;         /* Return value */
 
@@ -712,14 +709,13 @@ done:
 herr_t
 H5Gset_comment(hid_t loc_id, const char *name, const char *comment)
 {
-    H5G_loc_t   loc;                    /* Group's location */
-    herr_t      ret_value = SUCCEED;       /* Return value */
+    H5VL_object_t *vol_obj;             /* Object token of loc_id */
+    H5VL_loc_params_t loc_params;
+    herr_t      ret_value = SUCCEED;    /* Return value */
 
     FUNC_ENTER_API(FAIL)
     H5TRACE3("e", "i*s*s", loc_id, name, comment);
 
-    if(H5G_loc(loc_id, &loc) < 0)
-        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not a location")
     if(!name || !*name)
         HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "no name specified")
 
@@ -727,8 +723,18 @@ H5Gset_comment(hid_t loc_id, const char *name, const char *comment)
     if(H5CX_set_loc(loc_id) < 0)
         HGOTO_ERROR(H5E_SYM, H5E_CANTSET, FAIL, "can't set collective metadata read info")
 
+    /* Fill in location struct fields */
+    loc_params.type                         = H5VL_OBJECT_BY_NAME;
+    loc_params.loc_data.loc_by_name.name    = name;
+    loc_params.loc_data.loc_by_name.lapl_id = H5P_LINK_ACCESS_DEFAULT;
+    loc_params.obj_type                     = H5I_get_type(loc_id);
+
+    /* Get the location object */
+    if(NULL == (vol_obj = H5VL_vol_object(loc_id)))
+        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "invalid location identifier")
+
     /* Set the comment */
-    if(H5G_loc_set_comment(&loc, name, comment) < 0)
+    if(H5VL_object_optional(vol_obj, H5P_DATASET_XFER_DEFAULT, H5_REQUEST_NULL, H5VL_OBJECT_SET_COMMENT, loc_params, comment) < 0)
         HGOTO_ERROR(H5E_SYM, H5E_CANTSET, FAIL, "unable to set comment value")
 
 done:
@@ -762,14 +768,13 @@ done:
 int
 H5Gget_comment(hid_t loc_id, const char *name, size_t bufsize, char *buf)
 {
-    H5G_loc_t	loc;                    /* Group's location */
+    H5VL_object_t *vol_obj;             /* Object token of loc_id */
+    H5VL_loc_params_t loc_params;
     int	ret_value;                      /* Return value */
 
     FUNC_ENTER_API(FAIL)
     H5TRACE4("Is", "i*sz*s", loc_id, name, bufsize, buf);
 
-    if(H5G_loc(loc_id, &loc) < 0)
-        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not a location")
     if(!name || !*name)
         HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "no name specified")
     if(bufsize > 0 && !buf)
@@ -779,8 +784,18 @@ H5Gget_comment(hid_t loc_id, const char *name, size_t bufsize, char *buf)
     if(H5CX_set_loc(loc_id) < 0)
         HGOTO_ERROR(H5E_SYM, H5E_CANTSET, FAIL, "can't set collective metadata read info")
 
+    /* Fill in location struct fields */
+    loc_params.type                         = H5VL_OBJECT_BY_NAME;
+    loc_params.loc_data.loc_by_name.name    = name;
+    loc_params.loc_data.loc_by_name.lapl_id = H5P_LINK_ACCESS_DEFAULT;
+    loc_params.obj_type                     = H5I_get_type(loc_id);
+
+    /* Get the location object */
+    if(NULL == (vol_obj = H5VL_vol_object(loc_id)))
+        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "invalid location identifier")
+
     /* Get the comment */
-    if((ret_value = (int)H5G_loc_get_comment(&loc, name, buf, bufsize)) < 0)
+    if(H5VL_object_optional(vol_obj, H5P_DATASET_XFER_DEFAULT, H5_REQUEST_NULL, H5VL_OBJECT_GET_COMMENT, loc_params, buf, bufsize, &ret_value) < 0)
         HGOTO_ERROR(H5E_SYM, H5E_CANTGET, FAIL, "unable to get comment value")
 
 done:
@@ -816,20 +831,17 @@ herr_t
 H5Giterate(hid_t loc_id, const char *name, int *idx_p, H5G_iterate_t op,
     void *op_data)
 {
-    H5G_loc_t           loc;            /* Location of object               */
+    H5VL_object_t *vol_obj;             /* Object token of loc_id */
+    H5VL_loc_params_t   loc_params;
     H5G_link_iterate_t  lnk_op;         /* Link operator                    */
-    H5VL_object_t  *vol_obj;
     hsize_t             last_obj;       /* Index of last object looked at   */
-    hsize_t	            idx;            /* Internal location to hold index  */
-    hbool_t         vol_wrapper_set = FALSE;            /* Whether the VOL object wrapping context was set up */
+    hsize_t	        idx;            /* Internal location to hold index  */
     herr_t              ret_value;      /* Return value                     */
 
     FUNC_ENTER_API(FAIL)
     H5TRACE5("e", "i*s*Isx*x", loc_id, name, idx_p, op, op_data);
 
     /* Check args */
-    if(H5G_loc(loc_id, &loc) < 0)
-        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not a location ID")
     if(!name || !*name)
         HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "no name specified")
     if(idx_p && *idx_p < 0)
@@ -845,28 +857,25 @@ H5Giterate(hid_t loc_id, const char *name, int *idx_p, H5G_iterate_t op,
     lnk_op.op_type = H5G_LINK_OP_OLD;
     lnk_op.op_func.op_old = op;
 
+    /* Fill out location struct */
+    loc_params.type                         = H5VL_OBJECT_BY_NAME;
+    loc_params.loc_data.loc_by_name.name    = name;
+    loc_params.loc_data.loc_by_name.lapl_id = H5P_LINK_ACCESS_DEFAULT;
+    loc_params.obj_type                     = H5I_get_type(loc_id);
+
     /* Get the object pointer */
     if(NULL == (vol_obj = H5VL_vol_object(loc_id)))
         HGOTO_ERROR(H5E_ATOM, H5E_BADTYPE, (-1), "invalid identifier")
 
-    /* Set wrapper info in API context */
-    if(H5VL_set_vol_wrapper(vol_obj->data, vol_obj->connector) < 0)
-        HGOTO_ERROR(H5E_ATOM, H5E_CANTSET, (-1), "can't set VOL wrapper info")
-    vol_wrapper_set = TRUE;
-
-    /* Call private function */
-    if((ret_value = H5G_iterate(&loc, name, H5_INDEX_NAME, H5_ITER_INC, idx, &last_obj, &lnk_op, op_data)) < 0)
-        HGOTO_ERROR(H5E_SYM, H5E_BADITER, FAIL, "group iteration failed")
+    /* Call private iteration function, through VOL callback */
+    if((ret_value = H5VL_group_optional(vol_obj, H5P_DATASET_XFER_DEFAULT, H5_REQUEST_NULL, H5VL_GROUP_ITERATE_OLD, loc_params, idx, &last_obj, &lnk_op, op_data)) < 0)
+        HERROR(H5E_SYM, H5E_BADITER, "error iterating over group's links");
 
     /* Set the index we stopped at */
     if(idx_p)
         *idx_p = (int)last_obj;
 
 done:
-    /* Reset object wrapping info in API context */
-    if(vol_wrapper_set && H5VL_reset_vol_wrapper() < 0)
-        HDONE_ERROR(H5E_SYM, H5E_CANTSET, H5I_INVALID_HID, "can't reset VOL wrapper info")
-
     FUNC_LEAVE_API(ret_value)
 } /* end H5Giterate() */
 
@@ -890,29 +899,35 @@ done:
 herr_t
 H5Gget_num_objs(hid_t loc_id, hsize_t *num_objs)
 {
-    H5G_loc_t           loc;                    /* Location of object */
+    H5VL_object_t      *vol_obj;                /* Object token of loc_id */
+    H5I_type_t          id_type;                /* Type of ID */
+    H5VL_loc_params_t   loc_params;
     H5G_info_t          grp_info;               /* Group information */
-    H5O_type_t          obj_type;               /* Type of object at location */
-    herr_t              ret_value = SUCCEED;
+    herr_t              ret_value = SUCCEED;    /* Return value */
 
     FUNC_ENTER_API(FAIL)
     H5TRACE2("e", "i*h", loc_id, num_objs);
 
     /* Check args */
-    if(H5G_loc(loc_id, &loc) < 0)
-        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not a location ID")
-    if(H5O_obj_type(loc.oloc, &obj_type) < 0)
-        HGOTO_ERROR(H5E_ARGS, H5E_CANTGET, FAIL, "can't get object type")
-    if(obj_type != H5O_TYPE_GROUP)
-        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not a group")
+    id_type = H5I_get_type(loc_id);
+    if(!(H5I_GROUP == id_type || H5I_FILE == id_type))
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "invalid group (or file) ID")
     if(!num_objs)
         HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "bad pointer to # of objects")
 
-    /* Retrieve information about the group */
-    if(H5G__obj_info(loc.oloc, &grp_info) < 0)
-        HGOTO_ERROR(H5E_SYM, H5E_CANTCOUNT, FAIL, "can't determine # of objects")
+    /* Fill in location struct fields */
+    loc_params.type     = H5VL_OBJECT_BY_SELF;
+    loc_params.obj_type = id_type;
+
+    /* Get group location */
+    if(NULL == (vol_obj = (H5VL_object_t *)H5I_object(loc_id)))
+        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "invalid location identifier")
+
+    /* Retrieve the group's information */
+    if(H5VL_group_get(vol_obj, H5VL_GROUP_GET_INFO, H5P_DATASET_XFER_DEFAULT, H5_REQUEST_NULL, loc_params, &grp_info) < 0)
+        HGOTO_ERROR(H5E_SYM, H5E_CANTGET, FAIL, "unable to get group info")
 
-    /* Set the number of objects [sic: links] in the group */
+    /* Set the number of objects [i.e. links] in the group */
     *num_objs = grp_info.nlinks;
 
 done:
@@ -939,23 +954,40 @@ done:
  */
 herr_t
 H5Gget_objinfo(hid_t loc_id, const char *name, hbool_t follow_link,
-	       H5G_stat_t *statbuf/*out*/)
+    H5G_stat_t *statbuf/*out*/)
 {
-    H5G_loc_t	loc;                        /* Group's location */
-    herr_t      ret_value = SUCCEED;        /* Return value */
+    herr_t ret_value = SUCCEED;         /* Return value */
 
     FUNC_ENTER_API(FAIL)
     H5TRACE4("e", "i*sbx", loc_id, name, follow_link, statbuf);
 
     /* Check arguments */
-    if(H5G_loc(loc_id, &loc) < 0)
-        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not a location")
     if(!name || !*name)
         HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "no name specified")
 
-    /* Get info */
-    if(H5G__get_objinfo(&loc, name, follow_link, statbuf) < 0)
-        HGOTO_ERROR(H5E_SYM, H5E_CANTGET, FAIL, "cannot stat object")
+    /* Set up collective metadata if appropriate */
+    if(H5CX_set_loc(loc_id) < 0)
+        HGOTO_ERROR(H5E_SYM, H5E_CANTSET, FAIL, "can't set collective metadata read info")
+
+    /* Retrieve object info, if pointer to struct is given */
+    if(statbuf) {
+        H5VL_object_t      *vol_obj;        /* Object token of loc_id */
+        H5VL_loc_params_t   loc_params;
+
+        /* Fill out location struct */
+        loc_params.type                         = H5VL_OBJECT_BY_NAME;
+        loc_params.loc_data.loc_by_name.name    = name;
+        loc_params.loc_data.loc_by_name.lapl_id = H5P_LINK_ACCESS_DEFAULT;
+        loc_params.obj_type                     = H5I_get_type(loc_id);
+
+        /* Get the location object */
+        if(NULL == (vol_obj = H5VL_vol_object(loc_id)))
+            HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "invalid location identifier")
+
+        /* Retrieve the object's information */
+        if(H5VL_group_optional(vol_obj, H5P_DATASET_XFER_DEFAULT, H5_REQUEST_NULL, H5VL_GROUP_GET_OBJINFO, loc_params, (unsigned)follow_link, statbuf) < 0)
+            HGOTO_ERROR(H5E_SYM, H5E_CANTGET, FAIL, "can't get info for object: '%s'", name)
+    } /* end if */
 
 done:
     FUNC_LEAVE_API(ret_value)
@@ -980,6 +1012,7 @@ H5G__get_objinfo_cb(H5G_loc_t H5_ATTR_UNUSED *grp_loc/*in*/, const char *name, c
     H5G_loc_t *obj_loc, void *_udata/*in,out*/, H5G_own_loc_t *own_loc/*out*/)
 {
     H5G_trav_goi_t *udata = (H5G_trav_goi_t *)_udata;   /* User data passed in */
+    H5G_stat_t *statbuf = udata->statbuf;   /* Convenience pointer for statbuf */
     herr_t ret_value = SUCCEED;         /* Return value */
 
     FUNC_ENTER_STATIC
@@ -988,48 +1021,43 @@ H5G__get_objinfo_cb(H5G_loc_t H5_ATTR_UNUSED *grp_loc/*in*/, const char *name, c
     if(lnk == NULL && obj_loc == NULL)
         HGOTO_ERROR(H5E_SYM, H5E_NOTFOUND, FAIL, "'%s' doesn't exist", name)
 
-    /* Only modify user's buffer if it's available */
-    if(udata->statbuf) {
-        H5G_stat_t *statbuf = udata->statbuf;   /* Convenience pointer for statbuf */
-
-        /* Common code to retrieve the file's fileno */
-        if(H5F_get_fileno((obj_loc ? obj_loc : grp_loc)->oloc->file, &statbuf->fileno[0]) < 0)
-            HGOTO_ERROR(H5E_FILE, H5E_BADVALUE, FAIL, "unable to read fileno")
+    /* Common code to retrieve the file's fileno */
+    if(H5F_get_fileno((obj_loc ? obj_loc : grp_loc)->oloc->file, &statbuf->fileno[0]) < 0)
+        HGOTO_ERROR(H5E_FILE, H5E_BADVALUE, FAIL, "unable to read fileno")
 
-        /* Info for soft and UD links is gotten by H5L_get_info. If we have
-         *      a hard link, follow it and get info on the object
-         */
-        if(udata->follow_link || !lnk || (lnk->type == H5L_TYPE_HARD)) {
-            H5O_info_t oinfo;           /* Object information */
+    /* Info for soft and UD links is gotten by H5L_get_info. If we have
+     *      a hard link, follow it and get info on the object
+     */
+    if(udata->follow_link || !lnk || (lnk->type == H5L_TYPE_HARD)) {
+        H5O_info_t oinfo;           /* Object information */
 
-            /* Go retrieve the object information */
-            /* (don't need index & heap info) */
-            HDassert(obj_loc);
-            if(H5O_get_info(obj_loc->oloc, &oinfo, H5O_INFO_BASIC|H5O_INFO_TIME|H5O_INFO_HDR) < 0)
-                HGOTO_ERROR(H5E_OHDR, H5E_CANTGET, FAIL, "unable to get object info")
+        /* Go retrieve the object information */
+        /* (don't need index & heap info) */
+        HDassert(obj_loc);
+        if(H5O_get_info(obj_loc->oloc, &oinfo, H5O_INFO_BASIC|H5O_INFO_TIME|H5O_INFO_HDR) < 0)
+            HGOTO_ERROR(H5E_OHDR, H5E_CANTGET, FAIL, "unable to get object info")
 
-            /* Get mapped object type */
-            statbuf->type = H5G_map_obj_type(oinfo.type);
+        /* Get mapped object type */
+        statbuf->type = H5G_map_obj_type(oinfo.type);
 
-	    /* Get object number (i.e. address) for object */
-	    statbuf->objno[0] = (unsigned long)(oinfo.addr);
+        /* Get object number (i.e. address) for object */
+        statbuf->objno[0] = (unsigned long)(oinfo.addr);
 #if H5_SIZEOF_UINT64_T > H5_SIZEOF_LONG
-	    statbuf->objno[1] = (unsigned long)(oinfo.addr >> 8 * sizeof(long));
+        statbuf->objno[1] = (unsigned long)(oinfo.addr >> 8 * sizeof(long));
 #else
-	    statbuf->objno[1] = 0;
+        statbuf->objno[1] = 0;
 #endif
-            /* Get # of hard links pointing to object */
-	    statbuf->nlink = oinfo.rc;
+        /* Get # of hard links pointing to object */
+        statbuf->nlink = oinfo.rc;
 
-            /* Get modification time for object */
-            statbuf->mtime = oinfo.ctime;
+        /* Get modification time for object */
+        statbuf->mtime = oinfo.ctime;
 
-            /* Retrieve the object header information */
-            statbuf->ohdr.size = oinfo.hdr.space.total;
-            statbuf->ohdr.free = oinfo.hdr.space.free;
-            statbuf->ohdr.nmesgs = oinfo.hdr.nmesgs;
-            statbuf->ohdr.nchunks = oinfo.hdr.nchunks;
-        } /* end if */
+        /* Retrieve the object header information */
+        statbuf->ohdr.size = oinfo.hdr.space.total;
+        statbuf->ohdr.free = oinfo.hdr.space.free;
+        statbuf->ohdr.nmesgs = oinfo.hdr.nmesgs;
+        statbuf->ohdr.nchunks = oinfo.hdr.nchunks;
     } /* end if */
 
 done:
@@ -1057,22 +1085,22 @@ done:
  *
  *-------------------------------------------------------------------------
  */
-static herr_t
+herr_t
 H5G__get_objinfo(const H5G_loc_t *loc, const char *name, hbool_t follow_link,
     H5G_stat_t *statbuf/*out*/)
 {
     H5G_trav_goi_t udata;           /* User data for callback */
     herr_t      ret_value = SUCCEED;       /* Return value */
 
-    FUNC_ENTER_STATIC
+    FUNC_ENTER_PACKAGE
 
     /* Sanity checks */
     HDassert(loc);
     HDassert(name && *name);
+    HDassert(statbuf);
 
-    /* Reset stat buffer, if one was given */
-    if(statbuf)
-        HDmemset(statbuf, 0, sizeof(H5G_stat_t));
+    /* Reset stat buffer */
+    HDmemset(statbuf, 0, sizeof(H5G_stat_t));
 
     /* Set up user data for retrieving information */
     udata.statbuf = statbuf;
@@ -1080,12 +1108,11 @@ H5G__get_objinfo(const H5G_loc_t *loc, const char *name, hbool_t follow_link,
     udata.loc_file = loc->oloc->file;
 
     /* Traverse the group hierarchy to locate the object to get info about */
-    if(H5G_traverse(loc, name, (unsigned)(follow_link ? H5G_TARGET_NORMAL : H5G_TARGET_SLINK|H5G_TARGET_UDLINK),
-            H5G__get_objinfo_cb, &udata) < 0)
+    if(H5G_traverse(loc, name, (unsigned)(follow_link ? H5G_TARGET_NORMAL : (H5G_TARGET_SLINK | H5G_TARGET_UDLINK)), H5G__get_objinfo_cb, &udata) < 0)
         HGOTO_ERROR(H5E_SYM, H5E_EXISTS, FAIL, "name doesn't exist")
 
     /* If we're pointing at a soft or UD link, get the real link length and type */
-    if(statbuf && follow_link == 0) {
+    if(follow_link == 0) {
         H5L_info_t linfo;           /* Link information buffer */
         herr_t ret;
 
@@ -1137,24 +1164,33 @@ done:
 ssize_t
 H5Gget_objname_by_idx(hid_t loc_id, hsize_t idx, char *name, size_t size)
 {
-    H5G_loc_t           loc;            /* Object location */
-    H5O_type_t          obj_type;       /* Type of object at location */
-    ssize_t             ret_value;
+    H5VL_object_t      *vol_obj;        /* Object token of loc_id */
+    H5VL_loc_params_t   loc_params;
+    ssize_t             ret_value;      /* Return value */
 
     FUNC_ENTER_API(FAIL)
     H5TRACE4("Zs", "ih*sz", loc_id, idx, name, size);
 
-    /* Check args */
-    if(H5G_loc(loc_id, &loc) < 0)
-        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not a location ID")
-    if(H5O_obj_type(loc.oloc, &obj_type) < 0)
-        HGOTO_ERROR(H5E_ARGS, H5E_CANTGET, FAIL, "can't get object type")
-    if(obj_type != H5O_TYPE_GROUP)
-        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not a group")
+    /* Set up collective metadata if appropriate */
+    if(H5CX_set_loc(loc_id) < 0)
+        HGOTO_ERROR(H5E_SYM, H5E_CANTSET, (-1), "can't set collective metadata read info")
+
+    /* Fill in location struct fields */
+    loc_params.type                         = H5VL_OBJECT_BY_IDX;
+    loc_params.loc_data.loc_by_idx.name     = ".";
+    loc_params.loc_data.loc_by_idx.idx_type = H5_INDEX_NAME;
+    loc_params.loc_data.loc_by_idx.order    = H5_ITER_INC;
+    loc_params.loc_data.loc_by_idx.n        = idx;
+    loc_params.loc_data.loc_by_idx.lapl_id  = H5P_LINK_ACCESS_DEFAULT;
+    loc_params.obj_type                     = H5I_get_type(loc_id);
+
+    /* Get the location object */
+    if(NULL == (vol_obj = (H5VL_object_t *)H5I_object(loc_id)))
+        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, (-1), "invalid location identifier")
 
     /* Call internal function */
-    if((ret_value = H5G_obj_get_name_by_idx(loc.oloc, H5_INDEX_NAME, H5_ITER_INC, idx, name, size)) < 0)
-        HGOTO_ERROR(H5E_SYM, H5E_CANTGET, FAIL, "can't get object name")
+    if(H5VL_link_get(vol_obj, loc_params, H5VL_LINK_GET_NAME, H5P_DATASET_XFER_DEFAULT, H5_REQUEST_NULL, name, size, &ret_value) < 0)
+        HGOTO_ERROR(H5E_SYM, H5E_CANTGET, (-1), "can't get object name")
 
 done:
     FUNC_LEAVE_API(ret_value)
@@ -1179,82 +1215,39 @@ done:
 H5G_obj_t
 H5Gget_objtype_by_idx(hid_t loc_id, hsize_t idx)
 {
-    H5G_loc_t       loc;                /* Object location */
-    H5G_obj_t       ret_value;
+    H5VL_object_t *vol_obj;             /* Object token of loc_id */
+    H5VL_loc_params_t loc_params;
+    H5O_info_t oinfo;                   /* Object info (contains object type) */
+    unsigned fields;                    /* Which fields in object info to populate */
+    H5G_obj_t ret_value;                /* Return value */
 
     FUNC_ENTER_API(H5G_UNKNOWN)
     H5TRACE2("Go", "ih", loc_id, idx);
 
-    /* Check args */
-    if(H5G_loc(loc_id, &loc) < 0)
-        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, H5G_UNKNOWN, "not a location ID")
-
-    /* Call internal function*/
-    if(H5G_UNKNOWN == (ret_value = H5G__obj_get_type_by_idx(loc.oloc, idx)))
-        HGOTO_ERROR(H5E_SYM, H5E_BADTYPE, H5G_UNKNOWN, "can't get object type")
-
-done:
-    FUNC_LEAVE_API(ret_value)
-} /* end H5Gget_objtype_by_idx() */
-
-
-/*-------------------------------------------------------------------------
- * Function:	H5G__obj_get_type_by_idx
- *
- * Purpose:     Private function for H5Gget_objtype_by_idx.
- *              Returns the type of objects in the group by giving index.
- *
- * Return:	Success:        H5G_GROUP(1), H5G_DATASET(2), H5G_TYPE(3)
- *
- *		Failure:	Negative
- *
- * Programmer:	Raymond Lu
- *	        Nov 20, 2002
- *
- *-------------------------------------------------------------------------
- */
-static H5G_obj_t
-H5G__obj_get_type_by_idx(H5O_loc_t *oloc, hsize_t idx)
-{
-    H5O_linfo_t	linfo;		/* Link info message */
-    htri_t linfo_exists;        /* Whether the link info message exists */
-    H5O_type_t obj_type;        /* Type of object at location */
-    H5G_obj_t ret_value = H5G_UNKNOWN;  /* Return value */
+    /* Set location parameters */
+    loc_params.type = H5VL_OBJECT_BY_IDX;
+    loc_params.loc_data.loc_by_idx.name = ".";
+    loc_params.loc_data.loc_by_idx.idx_type = H5_INDEX_NAME;
+    loc_params.loc_data.loc_by_idx.order = H5_ITER_INC;
+    loc_params.loc_data.loc_by_idx.n = idx;
+    loc_params.loc_data.loc_by_idx.lapl_id  = H5P_LINK_ACCESS_DEFAULT;
+    loc_params.obj_type = H5I_get_type(loc_id);
 
-    FUNC_ENTER_STATIC_TAG(oloc->addr)
+    /* Get the location object */
+    if(NULL == (vol_obj = H5VL_vol_object(loc_id)))
+        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, H5G_UNKNOWN, "invalid location identifier")
 
-    /* Sanity check */
-    HDassert(oloc);
+    /* Retrieve the object's basic information (which includes its type) */
+    fields = H5O_INFO_BASIC;
+    if(H5VL_object_optional(vol_obj, H5P_DATASET_XFER_DEFAULT, H5_REQUEST_NULL, H5VL_OBJECT_GET_INFO, loc_params, &oinfo, fields) < 0)
+        HGOTO_ERROR(H5E_SYM, H5E_BADTYPE, H5G_UNKNOWN, "can't get object info")
 
-    /* Check args */
-    if(H5O_obj_type(oloc, &obj_type) < 0)
-        HGOTO_ERROR(H5E_SYM, H5E_CANTGET, H5G_UNKNOWN, "can't get object type")
-    if(obj_type != H5O_TYPE_GROUP)
-        HGOTO_ERROR(H5E_SYM, H5E_BADTYPE, H5G_UNKNOWN, "not a group")
-
-    /* Attempt to get the link info for this group */
-    if((linfo_exists = H5G__obj_get_linfo(oloc, &linfo)) < 0)
-        HGOTO_ERROR(H5E_SYM, H5E_CANTGET, H5G_UNKNOWN, "can't check for link info message")
-    if(linfo_exists) {
-        if(H5F_addr_defined(linfo.fheap_addr)) {
-            /* Get the object's name from the dense link storage */
-            if((ret_value = H5G__dense_get_type_by_idx(oloc->file, &linfo, idx)) < 0)
-                HGOTO_ERROR(H5E_SYM, H5E_NOTFOUND, H5G_UNKNOWN, "can't locate type")
-        } /* end if */
-        else {
-            /* Get the object's type from the link messages */
-            if((ret_value = H5G__compact_get_type_by_idx(oloc, &linfo, idx)) < 0)
-                HGOTO_ERROR(H5E_SYM, H5E_NOTFOUND, H5G_UNKNOWN, "can't locate type")
-        } /* end else */
-    } /* end if */
-    else {
-        /* Get the object's type from the symbol table */
-        if((ret_value = H5G__stab_get_type_by_idx(oloc, idx)) < 0)
-            HGOTO_ERROR(H5E_SYM, H5E_NOTFOUND, H5G_UNKNOWN, "can't locate type")
-    } /* end else */
+    /* Map to group object type */
+    if(H5G_UNKNOWN == (ret_value = H5G_map_obj_type(oinfo.type)))
+        HGOTO_ERROR(H5E_SYM, H5E_BADTYPE, H5G_UNKNOWN, "can't determine object type")
 
 done:
-    FUNC_LEAVE_NOAPI_TAG(ret_value)
-} /* end H5G__obj_get_type_by_idx() */
+    FUNC_LEAVE_API(ret_value)
+} /* end H5Gget_objtype_by_idx() */
 #endif /* H5_NO_DEPRECATED_SYMBOLS */
 
diff --git a/src/H5Gpkg.h b/src/H5Gpkg.h
index 836213d..ef330c4 100644
--- a/src/H5Gpkg.h
+++ b/src/H5Gpkg.h
@@ -299,6 +299,14 @@ typedef struct H5G_copy_file_ud_t {
     H5G_cache_t cache;                  /* Cached data for symbol table entry */
 } H5G_copy_file_ud_t;
 
+/* Types for optional group VOL operations */
+typedef enum H5VL_group_optional_t {
+#ifndef H5_NO_DEPRECATED_SYMBOLS
+    H5VL_GROUP_ITERATE_OLD,             /* HG5Giterate (deprecated routine) */
+    H5VL_GROUP_GET_OBJINFO              /* HG5Gget_objinfo (deprecated routine) */
+#endif /* H5_NO_DEPRECATED_SYMBOLS */
+} H5VL_group_optional_t;
+
 
 /*****************************/
 /* Package Private Variables */
@@ -381,9 +389,6 @@ H5_DLL herr_t H5G__stab_lookup_by_idx(const H5O_loc_t *grp_oloc, H5_iter_order_t
 #ifndef H5_STRICT_FORMAT_CHECKS
 H5_DLL herr_t H5G__stab_valid(H5O_loc_t *grp_oloc, H5O_stab_t *alt_stab);
 #endif /* H5_STRICT_FORMAT_CHECKS */
-#ifndef H5_NO_DEPRECATED_SYMBOLS
-H5_DLL H5G_obj_t H5G__stab_get_type_by_idx(H5O_loc_t *oloc, hsize_t idx);
-#endif /* H5_NO_DEPRECATED_SYMBOLS */
 
 
 /*
@@ -448,10 +453,6 @@ H5_DLL htri_t H5G__compact_lookup(const H5O_loc_t *grp_oloc, const char *name,
 H5_DLL herr_t H5G__compact_lookup_by_idx(const H5O_loc_t *oloc,
     const H5O_linfo_t *linfo, H5_index_t idx_type, H5_iter_order_t order,
     hsize_t n, H5O_link_t *lnk);
-#ifndef H5_NO_DEPRECATED_SYMBOLS
-H5_DLL H5G_obj_t H5G__compact_get_type_by_idx(H5O_loc_t *oloc, 
-    const H5O_linfo_t *linfo, hsize_t idx);
-#endif /* H5_NO_DEPRECATED_SYMBOLS */
 
 /* Functions that understand "dense" link storage */
 H5_DLL herr_t H5G__dense_build_table(H5F_t *f, const H5O_linfo_t *linfo,
@@ -476,10 +477,6 @@ H5_DLL herr_t H5G__dense_remove_by_idx(H5F_t *f, const H5O_linfo_t *linfo,
     H5RS_str_t *grp_full_path_r, H5_index_t idx_type, H5_iter_order_t order,
     hsize_t n);
 H5_DLL herr_t H5G__dense_delete(H5F_t *f, H5O_linfo_t *linfo, hbool_t adj_link);
-#ifndef H5_NO_DEPRECATED_SYMBOLS
-H5_DLL H5G_obj_t H5G__dense_get_type_by_idx(H5F_t  *f, H5O_linfo_t *linfo,
-    hsize_t idx);
-#endif /* H5_NO_DEPRECATED_SYMBOLS */
 
 /* Functions that understand group objects */
 H5_DLL herr_t H5G__obj_create(H5F_t *f, H5G_obj_create_t *gcrt_info,
@@ -494,6 +491,10 @@ H5_DLL herr_t H5G__obj_iterate(const H5O_loc_t *grp_oloc,
 H5_DLL herr_t H5G__obj_info(const H5O_loc_t *oloc, H5G_info_t *grp_info);
 H5_DLL htri_t H5G__obj_lookup(const H5O_loc_t *grp_oloc, const char *name,
     H5O_link_t *lnk);
+#ifndef H5_NO_DEPRECATED_SYMBOLS
+H5_DLL herr_t H5G__get_objinfo(const H5G_loc_t *loc, const char *name,
+    hbool_t follow_link, H5G_stat_t *statbuf/*out*/);
+#endif /* H5_NO_DEPRECATED_SYMBOLS */
 
 /*
  * These functions operate on group hierarchy names.
diff --git a/src/H5Gstab.c b/src/H5Gstab.c
index 9072b97..e8d38b9 100644
--- a/src/H5Gstab.c
+++ b/src/H5Gstab.c
@@ -1103,118 +1103,3 @@ done:
 } /* end H5G__stab_valid */
 #endif /* H5_STRICT_FORMAT_CHECKS */
 
-#ifndef H5_NO_DEPRECATED_SYMBOLS
-
-/*-------------------------------------------------------------------------
- * Function:	H5G_stab_get_type_by_idx_cb
- *
- * Purpose:     Callback for B-tree iteration 'by index' info query to
- *              retrieve the type of an object
- *
- * Return:	Success:        Non-negative
- *		Failure:	Negative
- *
- * Programmer:	Quincey Koziol
- *	        Nov  7, 2006
- *
- *-------------------------------------------------------------------------
- */
-static herr_t
-H5G_stab_get_type_by_idx_cb(const H5G_entry_t *ent, void *_udata)
-{
-    H5G_bt_it_gtbi_t	*udata = (H5G_bt_it_gtbi_t *)_udata;
-    herr_t ret_value = SUCCEED;         /* Return value */
-
-    FUNC_ENTER_NOAPI_NOINIT
-
-    /* Sanity check */
-    HDassert(ent);
-    HDassert(udata);
-
-    /* Check for a soft link */
-    switch(ent->type) {
-        case H5G_CACHED_SLINK:
-            udata->type = H5G_LINK;
-            break;
-
-        case H5G_CACHED_ERROR:
-        case H5G_NOTHING_CACHED:
-        case H5G_CACHED_STAB:
-        case H5G_NCACHED:
-        default:
-            {
-                H5O_loc_t tmp_oloc;             /* Temporary object location */
-                H5O_type_t obj_type;            /* Type of object at location */
-
-                /* Build temporary object location */
-                tmp_oloc.file = udata->f;
-                HDassert(H5F_addr_defined(ent->header));
-                tmp_oloc.addr = ent->header;
-
-                /* Get the type of the object */
-                if(H5O_obj_type(&tmp_oloc, &obj_type) < 0)
-                    HGOTO_ERROR(H5E_SYM, H5E_CANTGET, FAIL, "can't get object type")
-                udata->type = H5G_map_obj_type(obj_type);
-            }
-            break;
-    } /* end switch */
-
-done:
-    FUNC_LEAVE_NOAPI(ret_value)
-} /* end H5G_stab_get_type_by_idx_cb */
-
-
-/*-------------------------------------------------------------------------
- * Function:	H5G__stab_get_type_by_idx
- *
- * Purpose:     Private function for H5Gget_objtype_by_idx.
- *              Returns the type of objects in the group by giving index.
- *
- * Return:	Success:        H5G_GROUP(1), H5G_DATASET(2), H5G_TYPE(3)
- *
- *		Failure:	UNKNOWN
- *
- * Programmer:	Raymond Lu
- *	        Nov 20, 2002
- *
- *-------------------------------------------------------------------------
- */
-H5G_obj_t
-H5G__stab_get_type_by_idx(H5O_loc_t *oloc, hsize_t idx)
-{
-    H5O_stab_t		stab;	        /* Info about local heap & B-tree */
-    H5G_bt_it_gtbi_t	udata;          /* User data for B-tree callback */
-    H5G_obj_t		ret_value = H5G_UNKNOWN;        /* Return value */
-
-    FUNC_ENTER_PACKAGE_TAG(oloc->addr)
-
-    /* Sanity check */
-    HDassert(oloc);
-
-    /* Get the B-tree & local heap info */
-    if(NULL == H5O_msg_read(oloc, H5O_STAB_ID, &stab))
-        HGOTO_ERROR(H5E_SYM, H5E_NOTFOUND, H5G_UNKNOWN, "unable to determine local heap address")
-
-    /* Set iteration information */
-    udata.common.idx = idx;
-    udata.common.num_objs = 0;
-    udata.common.op = H5G_stab_get_type_by_idx_cb;
-    udata.f = oloc->file;
-    udata.type = H5G_UNKNOWN;
-
-    /* Iterate over the group members */
-    if(H5B_iterate(oloc->file, H5B_SNODE, stab.btree_addr, H5G__node_by_idx, &udata) < 0)
-        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, H5G_UNKNOWN, "iteration operator failed")
-
-    /* If we don't know the type now, we almost certainly went out of bounds */
-    if(udata.type == H5G_UNKNOWN)
-	HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, H5G_UNKNOWN, "index out of bound")
-
-    /* Set the return value */
-    ret_value = udata.type;
-
-done:
-    FUNC_LEAVE_NOAPI_TAG(ret_value)
-} /* end H5G__stab_get_type_by_idx() */
-#endif /* H5_NO_DEPRECATED_SYMBOLS */
-
diff --git a/src/H5I.c b/src/H5I.c
index 8a4b220..f4a221f 100644
--- a/src/H5I.c
+++ b/src/H5I.c
@@ -2164,36 +2164,27 @@ done:
 ssize_t
 H5Iget_name(hid_t id, char *name/*out*/, size_t size)
 {
-    H5VL_object_t  *vol_obj;
+    H5VL_object_t *vol_obj;     /* Object token of loc_id */
+    H5VL_loc_params_t loc_params;
     H5G_loc_t     loc;          /* Object location */
-    hbool_t         vol_wrapper_set = FALSE;            /* Whether the VOL object wrapping context was set up */
     ssize_t       ret_value;    /* Return value */
 
     FUNC_ENTER_API((-1))
     H5TRACE3("Zs", "ixz", id, name, size);
 
-    /* Get object location */
-    if(H5G_loc(id, &loc) < 0)
-        HGOTO_ERROR(H5E_ATOM, H5E_CANTGET, (-1), "can't retrieve object location")
-
     /* Get the object pointer */
     if(NULL == (vol_obj = H5VL_vol_object(id)))
         HGOTO_ERROR(H5E_ATOM, H5E_BADTYPE, (-1), "invalid identifier")
 
-    /* Set wrapper info in API context */
-    if(H5VL_set_vol_wrapper(vol_obj->data, vol_obj->connector) < 0)
-        HGOTO_ERROR(H5E_ATOM, H5E_CANTSET, (-1), "can't set VOL wrapper info")
-    vol_wrapper_set = TRUE;
+    /* Set location parameters */
+    loc_params.type         = H5VL_OBJECT_BY_SELF;
+    loc_params.obj_type     = H5I_get_type(id);
 
     /* Retrieve object's name */
-    if((ret_value = H5G_get_name(&loc, name, size, NULL)) < 0)
+    if(H5VL_object_get(vol_obj, loc_params, H5VL_ID_GET_NAME, H5P_DATASET_XFER_DEFAULT, H5_REQUEST_NULL, &ret_value, name, size) < 0)
         HGOTO_ERROR(H5E_ATOM, H5E_CANTGET, (-1), "can't retrieve object name")
 
 done:
-    /* Reset object wrapping info in API context */
-    if(vol_wrapper_set && H5VL_reset_vol_wrapper() < 0)
-        HDONE_ERROR(H5E_ATOM, H5E_CANTSET, (-1), "can't reset VOL wrapper info")
-
     FUNC_LEAVE_API(ret_value)
 } /* end H5Iget_name() */
 
diff --git a/src/H5Itest.c b/src/H5Itest.c
index 4b54835..79bc482 100644
--- a/src/H5Itest.c
+++ b/src/H5Itest.c
@@ -78,26 +78,41 @@
 ssize_t
 H5I__get_name_test(hid_t id, char *name/*out*/, size_t size, hbool_t *cached)
 {
+    H5VL_object_t *vol_obj;             /* Object token of id */
     H5G_loc_t   loc;                    /* Object location */
     hbool_t     api_ctx_pushed = FALSE; /* Whether API context pushed */
+    hbool_t     vol_wrapper_set = FALSE;/* Whether the VOL object wrapping context was set up */
     ssize_t     ret_value = -1;         /* Return value */
 
     FUNC_ENTER_PACKAGE
 
-    /* Get object location */
-    if(H5G_loc(id, &loc) < 0)
-        HGOTO_ERROR(H5E_ATOM, H5E_CANTGET, (-1), "can't retrieve object location")
-
     /* Set API context */
     if(H5CX_push() < 0)
         HGOTO_ERROR(H5E_SYM, H5E_CANTSET, (-1), "can't set API context")
     api_ctx_pushed = TRUE;
 
+    /* Get the object pointer */
+    if(NULL == (vol_obj = H5VL_vol_object(id)))
+        HGOTO_ERROR(H5E_ATOM, H5E_BADTYPE, (-1), "invalid identifier")
+
+    /* Set wrapper info in API context */
+    if(H5VL_set_vol_wrapper(vol_obj->data, vol_obj->connector) < 0)
+        HGOTO_ERROR(H5E_ATOM, H5E_CANTSET, FAIL, "can't set VOL wrapper info")
+    vol_wrapper_set = TRUE;
+
+    /* Get object location */
+    if(H5G_loc(id, &loc) < 0)
+        HGOTO_ERROR(H5E_ATOM, H5E_CANTGET, (-1), "can't retrieve object location")
+
     /* Call internal group routine to retrieve object's name */
     if((ret_value = H5G_get_name(&loc, name, size, cached)) < 0)
         HGOTO_ERROR(H5E_ATOM, H5E_CANTGET, (-1), "can't retrieve object name")
 
 done:
+    /* Reset object wrapping info in API context */
+    if(vol_wrapper_set && H5VL_reset_vol_wrapper() < 0)
+        HDONE_ERROR(H5E_ATOM, H5E_CANTRESET, FAIL, "can't reset VOL wrapper info")
+
     if(api_ctx_pushed && H5CX_pop() < 0)
         HDONE_ERROR(H5E_SYM, H5E_CANTRESET, (-1), "can't reset API context")
 
diff --git a/src/H5O.c b/src/H5O.c
index 5c3a0a6..01b16ce 100644
--- a/src/H5O.c
+++ b/src/H5O.c
@@ -100,7 +100,7 @@
 hid_t
 H5Oopen(hid_t loc_id, const char *name, hid_t lapl_id)
 {
-    H5VL_object_t  *vol_obj         = NULL;                     /* Object token of loc_id */
+    H5VL_object_t *vol_obj;             /* Object token of loc_id */
     H5I_type_t      opened_type;
     void           *opened_obj  = NULL;
     H5VL_loc_params_t loc_params;
@@ -169,7 +169,7 @@ hid_t
 H5Oopen_by_idx(hid_t loc_id, const char *group_name, H5_index_t idx_type,
     H5_iter_order_t order, hsize_t n, hid_t lapl_id)
 {
-    H5VL_object_t *vol_obj = NULL;        /* object token of loc_id */
+    H5VL_object_t *vol_obj;             /* Object token of loc_id */
     H5I_type_t opened_type;
     void *opened_obj = NULL;
     H5VL_loc_params_t loc_params;
@@ -252,7 +252,7 @@ done:
 hid_t
 H5Oopen_by_addr(hid_t loc_id, haddr_t addr)
 {
-    H5VL_object_t *vol_obj = NULL;        /* object token of loc_id */
+    H5VL_object_t *vol_obj;             /* Object token of loc_id */
     H5I_type_t opened_type;
     void *opened_obj = NULL;
     H5VL_loc_params_t loc_params;
@@ -407,7 +407,7 @@ done:
 herr_t
 H5Oincr_refcount(hid_t object_id)
 {
-    H5VL_object_t    *vol_obj = NULL;        /* object token of loc_id */
+    H5VL_object_t *vol_obj;             /* Object token of loc_id */
     H5VL_loc_params_t loc_params;
     herr_t      ret_value = SUCCEED;
 
@@ -457,7 +457,7 @@ done:
 herr_t
 H5Odecr_refcount(hid_t object_id)
 {
-    H5VL_object_t    *vol_obj = NULL;        /* object token of loc_id */
+    H5VL_object_t *vol_obj;             /* Object token of loc_id */
     H5VL_loc_params_t loc_params;
     herr_t      ret_value = SUCCEED;	/* Return value */
 
@@ -500,7 +500,7 @@ done:
 htri_t
 H5Oexists_by_name(hid_t loc_id, const char *name, hid_t lapl_id)
 {
-    H5VL_object_t  *vol_obj         = NULL;         /* Object token of loc_id */
+    H5VL_object_t *vol_obj;             /* Object token of loc_id */
     H5VL_loc_params_t loc_params;
     htri_t      ret_value = FAIL;       /* Return value */
 
@@ -553,7 +553,7 @@ done:
 herr_t
 H5Oget_info2(hid_t loc_id, H5O_info_t *oinfo, unsigned fields)
 {
-    H5VL_object_t      *vol_obj         = NULL;         /* Object token of loc_id */
+    H5VL_object_t *vol_obj;             /* Object token of loc_id */
     H5VL_loc_params_t   loc_params;
     herr_t      ret_value = SUCCEED;    /* Return value */
 
@@ -601,7 +601,7 @@ herr_t
 H5Oget_info_by_name2(hid_t loc_id, const char *name, H5O_info_t *oinfo,
     unsigned fields, hid_t lapl_id)
 {
-    H5VL_object_t    *vol_obj = NULL;        /* object token of loc_id */
+    H5VL_object_t *vol_obj;             /* Object token of loc_id */
     H5VL_loc_params_t loc_params;
     herr_t      ret_value = SUCCEED;    /* Return value */
 
@@ -661,7 +661,7 @@ herr_t
 H5Oget_info_by_idx2(hid_t loc_id, const char *group_name, H5_index_t idx_type,
     H5_iter_order_t order, hsize_t n, H5O_info_t *oinfo, unsigned fields, hid_t lapl_id)
 {
-    H5VL_object_t    *vol_obj = NULL;        /* object token of loc_id */
+    H5VL_object_t *vol_obj;             /* Object token of loc_id */
     H5VL_loc_params_t loc_params;
     herr_t      ret_value = SUCCEED;    /* Return value */
 
@@ -726,7 +726,7 @@ done:
 herr_t
 H5Oset_comment(hid_t obj_id, const char *comment)
 {
-    H5VL_object_t    *vol_obj = NULL;        /* object token of loc_id */
+    H5VL_object_t *vol_obj;             /* Object token of loc_id */
     H5VL_loc_params_t loc_params;
     herr_t      ret_value = SUCCEED;    /* Return value */
 
@@ -775,7 +775,7 @@ herr_t
 H5Oset_comment_by_name(hid_t loc_id, const char *name, const char *comment,
     hid_t lapl_id)
 {
-    H5VL_object_t    *vol_obj = NULL;        /* object token of loc_id */
+    H5VL_object_t *vol_obj;             /* Object token of loc_id */
     H5VL_loc_params_t loc_params;
     herr_t      ret_value = SUCCEED;    /* Return value */
 
@@ -828,7 +828,7 @@ done:
 ssize_t
 H5Oget_comment(hid_t obj_id, char *comment, size_t bufsize)
 {
-    H5VL_object_t    *vol_obj = NULL;        /* object token of loc_id */
+    H5VL_object_t *vol_obj;             /* Object token of loc_id */
     H5VL_loc_params_t loc_params;
     ssize_t     ret_value = -1;              /* Return value */
 
@@ -872,7 +872,7 @@ ssize_t
 H5Oget_comment_by_name(hid_t loc_id, const char *name, char *comment, size_t bufsize,
     hid_t lapl_id)
 {
-    H5VL_object_t    *vol_obj = NULL;        /* object token of loc_id */
+    H5VL_object_t *vol_obj;             /* Object token of loc_id */
     H5VL_loc_params_t loc_params;
     ssize_t     ret_value = -1;              /* Return value */
 
@@ -945,7 +945,7 @@ herr_t
 H5Ovisit2(hid_t obj_id, H5_index_t idx_type, H5_iter_order_t order,
     H5O_iterate_t op, void *op_data, unsigned fields)
 {
-    H5VL_object_t      *vol_obj         = NULL;     /* Object token of loc_id */
+    H5VL_object_t *vol_obj;             /* Object token of loc_id */
     H5VL_loc_params_t   loc_params;
     herr_t              ret_value;              /* Return value */
 
@@ -1018,7 +1018,7 @@ herr_t
 H5Ovisit_by_name2(hid_t loc_id, const char *obj_name, H5_index_t idx_type,
     H5_iter_order_t order, H5O_iterate_t op, void *op_data, unsigned fields, hid_t lapl_id)
 {
-    H5VL_object_t       *vol_obj        = NULL;     /* Object token of loc_id */
+    H5VL_object_t *vol_obj;             /* Object token of loc_id */
     H5VL_loc_params_t   loc_params; 
     herr_t              ret_value;              /* Return value */
 
diff --git a/src/H5Oattribute.c b/src/H5Oattribute.c
index 1d509e5..6e135c5 100644
--- a/src/H5Oattribute.c
+++ b/src/H5Oattribute.c
@@ -1304,7 +1304,7 @@ H5O_attr_iterate_real(hid_t loc_id, const H5O_loc_t *loc, H5_index_t idx_type,
 
         /* Iterate over attributes in table */
         if((ret_value = H5A__attr_iterate_table(&atable, skip, last_attr, loc_id, attr_op, op_data)) < 0)
-            HERROR(H5E_ATTR, H5E_CANTNEXT, "iteration operator failed");
+            HERROR(H5E_ATTR, H5E_BADITER, "iteration operator failed");
     } /* end else */
 
 done:
diff --git a/src/H5Oint.c b/src/H5Oint.c
index 3a60d9d..059a8a8 100644
--- a/src/H5Oint.c
+++ b/src/H5Oint.c
@@ -2114,7 +2114,7 @@ H5O_get_info(const H5O_loc_t *loc, H5O_info_t *oinfo, unsigned fields)
 
         /* Set the object's reference count */
         oinfo->rc = oh->nlink;
-    } 
+    } /* end if */
 
     /* Get time information, if requested */
     if(fields & H5O_INFO_TIME) {
diff --git a/src/H5Opkg.h b/src/H5Opkg.h
index 7254edb..dbc8089 100644
--- a/src/H5Opkg.h
+++ b/src/H5Opkg.h
@@ -414,13 +414,6 @@ typedef struct H5O_chk_cache_ud_t {
     H5O_common_cache_ud_t common;       /* Common object header cache callback info */
 } H5O_chk_cache_ud_t;
 
-/* types for object optional VOL operations */
-typedef enum H5VL_object_optional_t {
-    H5VL_OBJECT_GET_COMMENT,            /* get object comment                   */
-    H5VL_OBJECT_GET_INFO,               /* get object info                      */
-    H5VL_OBJECT_SET_COMMENT             /* set object comment                   */
-} H5VL_object_optional_t;
-
 /* Header message ID to class mapping */
 H5_DLLVAR const H5O_msg_class_t *const H5O_msg_class_g[H5O_MSG_TYPES];
 
diff --git a/src/H5Oprivate.h b/src/H5Oprivate.h
index 048e13e..e8565b9 100644
--- a/src/H5Oprivate.h
+++ b/src/H5Oprivate.h
@@ -851,6 +851,12 @@ typedef struct {
     } u;
 } H5O_mesg_operator_t;
 
+/* Types for object optional VOL operations */
+typedef enum H5VL_object_optional_t {
+    H5VL_OBJECT_GET_COMMENT,            /* get object comment                   */
+    H5VL_OBJECT_GET_INFO,               /* get object info                      */
+    H5VL_OBJECT_SET_COMMENT             /* set object comment                   */
+} H5VL_object_optional_t;
 
 /* Typedef for abstract object creation */
 typedef struct {
diff --git a/src/H5Plcpl.c b/src/H5Plcpl.c
index 6568ecd..16be52a 100644
--- a/src/H5Plcpl.c
+++ b/src/H5Plcpl.c
@@ -55,7 +55,7 @@
 
 /* Definitions for Location params */
 #define H5L_CRT_LOCATION_SIZE       sizeof(H5VL_loc_params_t)
-#define H5L_CRT_LOCATION_DEF        {H5I_BADID, H5VL_OBJECT_BY_SELF, {HADDR_UNDEF}}
+#define H5L_CRT_LOCATION_DEF        {H5I_BADID, H5VL_OBJECT_BY_SELF, {{HADDR_UNDEF}}}
 
 /* Definitions for target object NAME */
 #define H5L_CRT_TARGET_NAME_SIZE    sizeof(char *)
diff --git a/src/H5Rint.c b/src/H5Rint.c
index 7142d54..365facd 100644
--- a/src/H5Rint.c
+++ b/src/H5Rint.c
@@ -728,7 +728,7 @@ H5R__get_name(H5F_t *f, H5R_type_t ref_type, const void *_ref,
             UINT32DECODE(p, hobjid.idx);
 
             /* Get the dataset region from the heap (allocate inside routine) */
-            if ((buf = (uint8_t *)H5HG_read(oloc.file, &hobjid, NULL, NULL)) == NULL)
+            if((buf = (uint8_t *)H5HG_read(oloc.file, &hobjid, NULL, NULL)) == NULL)
                 HGOTO_ERROR(H5E_REFERENCE, H5E_READERROR, (-1), "Unable to read dataset region information")
 
             /* Get the object oid for the dataset */
@@ -748,7 +748,7 @@ H5R__get_name(H5F_t *f, H5R_type_t ref_type, const void *_ref,
     } /* end switch */
 
     /* Get name, length, etc. */
-    if ((ret_value = H5G_get_name_by_addr(f, &oloc, name, size)) < 0)
+    if((ret_value = H5G_get_name_by_addr(f, &oloc, name, size)) < 0)
         HGOTO_ERROR(H5E_REFERENCE, H5E_CANTGET, (-1), "can't determine name")
 
 done:
diff --git a/src/H5VLcallback.c b/src/H5VLcallback.c
index 25c5e7b..557105a 100644
--- a/src/H5VLcallback.c
+++ b/src/H5VLcallback.c
@@ -1049,6 +1049,7 @@ H5VLattr_read(void *obj, hid_t connector_id, hid_t mem_type_id, void *buf, hid_t
     herr_t ret_value = SUCCEED;         /* Return value */
 
     FUNC_ENTER_API_NOINIT
+    H5TRACE6("e", "*xii*xi**x", obj, connector_id, mem_type_id, buf, dxpl_id, req);
 
     /* Check args and get class pointer */
     if(NULL == obj)
@@ -1151,6 +1152,7 @@ H5VLattr_write(void *obj, hid_t connector_id, hid_t mem_type_id, const void *buf
     herr_t ret_value = SUCCEED;         /* Return value */
 
     FUNC_ENTER_API_NOINIT
+    H5TRACE6("e", "*xii*xi**x", obj, connector_id, mem_type_id, buf, dxpl_id, req);
 
     /* Check args and get class pointer */
     if(NULL == obj)
@@ -1261,7 +1263,8 @@ H5VLattr_get(void *obj, hid_t connector_id, H5VL_attr_get_t get_type, hid_t dxpl
     herr_t ret_value = SUCCEED;         /* Return value */
 
     FUNC_ENTER_API_NOINIT
-    H5TRACE6("e", "*xiVai**xx", obj, connector_id, get_type, dxpl_id, req, arguments);
+    H5TRACE6("e", "*xiVai**xx", obj, connector_id, get_type, dxpl_id, req,
+             arguments);
 
     /* Check args and get class pointer */
     if(NULL == obj)
@@ -1414,7 +1417,7 @@ H5VL__attr_optional(void *obj, const H5VL_class_t *cls, hid_t dxpl_id,
         HGOTO_ERROR(H5E_VOL, H5E_UNSUPPORTED, FAIL, "VOL connector has no 'attr optional' method")
 
     /* Call the corresponding VOL callback */
-    if((cls->attr_cls.optional)(obj, dxpl_id, req, arguments) < 0)
+    if((ret_value = (cls->attr_cls.optional)(obj, dxpl_id, req, arguments)) < 0)
         HGOTO_ERROR(H5E_VOL, H5E_CANTOPERATE, FAIL, "unable to execute attribute optional callback")
 
 done:
@@ -1450,7 +1453,7 @@ H5VL_attr_optional(const H5VL_object_t *vol_obj, hid_t dxpl_id, void **req, ...)
     /* Call the corresponding internal VOL routine */
     va_start(arguments, req);
     arg_started = TRUE;
-    if(H5VL__attr_optional(vol_obj->data, vol_obj->connector->cls, dxpl_id, req, arguments) < 0)
+    if((ret_value = H5VL__attr_optional(vol_obj->data, vol_obj->connector->cls, dxpl_id, req, arguments)) < 0)
         HGOTO_ERROR(H5E_VOL, H5E_CANTOPERATE, FAIL, "unable to execute attribute optional callback")
 
 done:
@@ -1492,7 +1495,7 @@ H5VLattr_optional(void *obj, hid_t connector_id, hid_t dxpl_id, void **req, va_l
         HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not a VOL connector ID")
 
     /* Call the corresponding internal VOL routine */
-    if(H5VL__attr_optional(obj, cls, dxpl_id, req, arguments) < 0)
+    if((ret_value = H5VL__attr_optional(obj, cls, dxpl_id, req, arguments)) < 0)
         HGOTO_ERROR(H5E_VOL, H5E_CANTOPERATE, FAIL, "unable to execute attribute optional callback")
 
 done:
@@ -2107,7 +2110,8 @@ H5VLdataset_get(void *obj, hid_t connector_id, H5VL_dataset_get_t get_type,
     herr_t ret_value = SUCCEED;         /* Return value */
 
     FUNC_ENTER_API_NOINIT
-    H5TRACE6("e", "*xiVci**xx", obj, connector_id, get_type, dxpl_id, req, arguments);
+    H5TRACE6("e", "*xiVci**xx", obj, connector_id, get_type, dxpl_id, req,
+             arguments);
 
     /* Check args and get class pointer */
     if(NULL == obj)
@@ -2702,7 +2706,8 @@ H5VLfile_get(void *obj, hid_t connector_id, H5VL_file_get_t get_type,
     herr_t ret_value = SUCCEED;         /* Return value */
 
     FUNC_ENTER_API_NOINIT
-    H5TRACE6("e", "*xiVgi**xx", obj, connector_id, get_type, dxpl_id, req, arguments);
+    H5TRACE6("e", "*xiVgi**xx", obj, connector_id, get_type, dxpl_id, req,
+             arguments);
 
     /* Check args and get class pointer */
     if(NULL == obj)
@@ -3381,7 +3386,8 @@ H5VLgroup_get(void *obj, hid_t connector_id, H5VL_group_get_t get_type,
     herr_t ret_value = SUCCEED;         /* Return value */
 
     FUNC_ENTER_API_NOINIT
-    H5TRACE6("e", "*xiVii**xx", obj, connector_id, get_type, dxpl_id, req, arguments);
+    H5TRACE6("e", "*xiVii**xx", obj, connector_id, get_type, dxpl_id, req,
+             arguments);
 
     /* Check args and get class pointer */
     if(NULL == obj)
@@ -3533,7 +3539,7 @@ H5VL__group_optional(void *obj, const H5VL_class_t *cls, hid_t dxpl_id,
         HGOTO_ERROR(H5E_VOL, H5E_UNSUPPORTED, FAIL, "VOL connector has no 'group optional' method")
 
     /* Call the corresponding VOL callback */
-    if((cls->group_cls.optional)(obj, dxpl_id, req, arguments) < 0)
+    if((ret_value = (cls->group_cls.optional)(obj, dxpl_id, req, arguments)) < 0)
         HGOTO_ERROR(H5E_VOL, H5E_CANTOPERATE, FAIL, "unable to execute group optional callback")
 
 done:
@@ -3569,7 +3575,7 @@ H5VL_group_optional(const H5VL_object_t *vol_obj, hid_t dxpl_id, void **req, ...
     /* Call the corresponding internal VOL routine */
     va_start(arguments, req);
     arg_started = TRUE;
-    if(H5VL__group_optional(vol_obj->data, vol_obj->connector->cls, dxpl_id, req, arguments) < 0)
+    if((ret_value = H5VL__group_optional(vol_obj->data, vol_obj->connector->cls, dxpl_id, req, arguments)) < 0)
         HGOTO_ERROR(H5E_VOL, H5E_CANTOPERATE, FAIL, "unable to execute group optional callback")
 
 done:
@@ -3612,7 +3618,7 @@ H5VLgroup_optional(void *obj, hid_t connector_id, hid_t dxpl_id, void **req,
         HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not a VOL connector ID")
 
     /* Call the corresponding internal VOL routine */
-    if(H5VL__group_optional(obj, cls, dxpl_id, req, arguments) < 0)
+    if((ret_value = H5VL__group_optional(obj, cls, dxpl_id, req, arguments)) < 0)
         HGOTO_ERROR(H5E_VOL, H5E_CANTOPERATE, FAIL, "unable to execute group optional callback")
 
 done:
@@ -3831,8 +3837,8 @@ H5VLlink_create(H5VL_link_create_type_t create_type, void *obj, H5VL_loc_params_
     herr_t ret_value = SUCCEED;         /* Return value */
 
     FUNC_ENTER_API_NOINIT
-    H5TRACE8("e", "Vk*xxiiii**x", create_type, obj, loc_params, connector_id, lcpl_id,
-             lapl_id, dxpl_id, req);
+    H5TRACE8("e", "Vk*xxiiii**x", create_type, obj, loc_params, connector_id,
+             lcpl_id, lapl_id, dxpl_id, req);
 
     /* Get class pointer */
     if(NULL == (cls = (H5VL_class_t *)H5I_object_verify(connector_id, H5I_VOL)))
@@ -4159,8 +4165,8 @@ H5VLlink_get(void *obj, H5VL_loc_params_t loc_params, hid_t connector_id, H5VL_l
     herr_t ret_value = SUCCEED;         /* Return value */
 
     FUNC_ENTER_API_NOINIT
-    H5TRACE7("e", "*xxiVli**xx", obj, loc_params, connector_id, get_type, dxpl_id, req,
-             arguments);
+    H5TRACE7("e", "*xxiVli**xx", obj, loc_params, connector_id, get_type, dxpl_id,
+             req, arguments);
 
     /* Check args and get class pointer */
     if(NULL == obj)
@@ -4484,7 +4490,8 @@ H5VLobject_open(void *obj, H5VL_loc_params_t params, hid_t connector_id, H5I_typ
     void *ret_value = NULL;             /* Return value */
 
     FUNC_ENTER_API_NOINIT
-    H5TRACE6("*x", "*xxi*Iti**x", obj, params, connector_id, opened_type, dxpl_id, req);
+    H5TRACE6("*x", "*xxi*Iti**x", obj, params, connector_id, opened_type, dxpl_id,
+             req);
 
     /* Check args and get class pointer */
     if(NULL == obj)
@@ -4597,6 +4604,9 @@ H5VLobject_copy(void *src_obj, H5VL_loc_params_t src_loc_params,
     herr_t ret_value = SUCCEED;         /* Return value */
 
     FUNC_ENTER_API_NOINIT
+    H5TRACE11("e", "*xx*s*xx*siiii**x", src_obj, src_loc_params, src_name,
+             dst_obj, dst_loc_params, dst_name, connector_id, ocpypl_id, lcpl_id,
+             dxpl_id, req);
 
     /* Check args and get class pointers */
     if(NULL == src_obj || NULL == dst_obj)
@@ -4707,8 +4717,8 @@ H5VLobject_get(void *obj, H5VL_loc_params_t loc_params, hid_t connector_id, H5VL
     herr_t ret_value = SUCCEED;         /* Return value */
 
     FUNC_ENTER_API_NOINIT
-    H5TRACE7("e", "*xxiVni**xx", obj, loc_params, connector_id, get_type, dxpl_id, req,
-             arguments);
+    H5TRACE7("e", "*xxiVni**xx", obj, loc_params, connector_id, get_type, dxpl_id,
+             req, arguments);
 
     /* Check args and get class pointer */
     if(NULL == obj)
@@ -5256,7 +5266,8 @@ H5VLdatatype_get(void *obj, hid_t connector_id, H5VL_datatype_get_t get_type,
     herr_t ret_value = SUCCEED;         /* Return value */
 
     FUNC_ENTER_API_NOINIT
-    H5TRACE6("e", "*xiVei**xx", obj, connector_id, get_type, dxpl_id, req, arguments);
+    H5TRACE6("e", "*xiVei**xx", obj, connector_id, get_type, dxpl_id, req,
+             arguments);
 
     /* Check args and get class pointer */
     if(NULL == obj)
@@ -5694,6 +5705,7 @@ H5VLrequest_wait(void *req, hid_t connector_id, uint64_t timeout, H5ES_status_t
     herr_t ret_value = SUCCEED;         /* Return value */
 
     FUNC_ENTER_API_NOINIT
+    H5TRACE4("e", "*xiUL*Es", req, connector_id, timeout, status);
 
     /* Get class pointer */
     if(NULL == (cls = (H5VL_class_t *)H5I_object_verify(connector_id, H5I_VOL)))
@@ -5914,6 +5926,7 @@ H5VLrequest_specific(void *req, hid_t connector_id, H5VL_request_specific_t spec
     herr_t ret_value = SUCCEED;         /* Return value */
 
     FUNC_ENTER_API_NOINIT
+    H5TRACE4("e", "*xiVrx", req, connector_id, specific_type, arguments);
 
     /* Get class pointer */
     if(NULL == (cls = (H5VL_class_t *)H5I_object_verify(connector_id, H5I_VOL)))
@@ -6026,6 +6039,7 @@ H5VLrequest_optional(void *req, hid_t connector_id, va_list arguments)
     herr_t ret_value = SUCCEED;         /* Return value */
 
     FUNC_ENTER_API_NOINIT
+    H5TRACE3("e", "*xix", req, connector_id, arguments);
 
     /* Get class pointer */
     if(NULL == (cls = (H5VL_class_t *)H5I_object_verify(connector_id, H5I_VOL)))
diff --git a/src/H5VLnative.c b/src/H5VLnative.c
index 7b15828..bf847c5 100644
--- a/src/H5VLnative.c
+++ b/src/H5VLnative.c
@@ -59,6 +59,7 @@ static herr_t H5VL__native_attr_read(void *attr, hid_t dtype_id, void *buf, hid_
 static herr_t H5VL__native_attr_write(void *attr, hid_t dtype_id, const void *buf, hid_t dxpl_id, void **req);
 static herr_t H5VL__native_attr_get(void *obj, H5VL_attr_get_t get_type, hid_t dxpl_id, void **req, va_list arguments);
 static herr_t H5VL__native_attr_specific(void *obj, H5VL_loc_params_t loc_params, H5VL_attr_specific_t specific_type, hid_t dxpl_id, void **req, va_list arguments);
+static herr_t H5VL__native_attr_optional(void *obj, hid_t dxpl_id, void **req, va_list arguments);
 static herr_t H5VL__native_attr_close(void *attr, hid_t dxpl_id, void **req);
 
 /* Dataset callbacks */
@@ -85,7 +86,8 @@ static herr_t H5VL__native_file_close(void *file, hid_t dxpl_id, void **req);
 static void *H5VL__native_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__native_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__native_group_get(void *obj, H5VL_group_get_t get_type, hid_t dxpl_id, void **req, va_list arguments);
-static herr_t H5VL__native_group_specific(void *dset, H5VL_group_specific_t specific_type, hid_t dxpl_id, void **req, va_list arguments);
+static herr_t H5VL__native_group_specific(void *obj, H5VL_group_specific_t specific_type, hid_t dxpl_id, void **req, va_list arguments);
+static herr_t H5VL__native_group_optional(void *obj, hid_t dxpl_id, void **req, va_list arguments);
 static herr_t H5VL__native_group_close(void *grp, hid_t dxpl_id, void **req);
 
 /* Link callbacks */
@@ -139,7 +141,7 @@ static H5VL_class_t H5VL_native_cls_g = {
         H5VL__native_attr_write,                    /* write        */
         H5VL__native_attr_get,                      /* get          */
         H5VL__native_attr_specific,                 /* specific     */
-        NULL,                                       /* optional     */
+        H5VL__native_attr_optional,                 /* optional     */
         H5VL__native_attr_close                     /* close        */
     },
     {   /* dataset_cls */
@@ -173,7 +175,7 @@ static H5VL_class_t H5VL_native_cls_g = {
         H5VL__native_group_open,                    /* open         */
         H5VL__native_group_get,                     /* get          */
         H5VL__native_group_specific,                /* specific     */
-        NULL,                                       /* optional     */
+        H5VL__native_group_optional,                /* optional     */
         H5VL__native_group_close                    /* close        */
     },
     {   /* link_cls */
@@ -796,6 +798,51 @@ done:
 
 
 /*-------------------------------------------------------------------------
+ * Function:    H5VL__native_attr_optional
+ *
+ * Purpose:     Perform a connector-specific operation on a native attribute
+ *
+ * Return:      SUCCEED/FAIL
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+H5VL__native_attr_optional(void H5_ATTR_UNUSED *obj, hid_t H5_ATTR_UNUSED dxpl_id,
+    void H5_ATTR_UNUSED **req, va_list arguments)
+{
+    H5VL_attr_optional_t optional_type;
+    herr_t ret_value = SUCCEED;    /* Return value */
+
+    FUNC_ENTER_STATIC
+
+    optional_type = va_arg(arguments, H5VL_attr_optional_t);
+    switch(optional_type) {
+#ifndef H5_NO_DEPRECATED_SYMBOLS
+        case H5VL_ATTR_ITERATE_OLD:
+            {
+                hid_t loc_id = va_arg(arguments, hid_t);
+                unsigned *attr_num = va_arg(arguments, unsigned *);
+                H5A_operator1_t op = va_arg(arguments, H5A_operator1_t);
+                void *op_data = va_arg(arguments, void *);
+
+                /* Call the actual iteration routine */
+                if((ret_value = H5A__iterate_old(loc_id, attr_num, op, op_data)) < 0)
+                    HERROR(H5E_VOL, H5E_BADITER, "error iterating over attributes");
+
+                break;
+            }
+#endif /* H5_NO_DEPRECATED_SYMBOLS */
+
+        default:
+            HGOTO_ERROR(H5E_VOL, H5E_UNSUPPORTED, FAIL, "invalid optional operation")
+    } /* end switch */
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5VL__native_attr_optional() */
+
+
+/*-------------------------------------------------------------------------
  * Function:	H5VL__native_attr_close
  *
  * Purpose:	Closes an attribute.
@@ -1551,14 +1598,14 @@ H5VL__native_file_get(void *obj, H5VL_file_get_t get_type,
                     /* Check for SWMR write access on the file */
                     if(H5F_INTENT(f) & H5F_ACC_SWMR_WRITE)
                         *intent_flags |= H5F_ACC_SWMR_WRITE;
-                }
+                } /* end if */
                 else {
                     *intent_flags = H5F_ACC_RDONLY;
 
                     /* Check for SWMR read access on the file */
                     if(H5F_INTENT(f) & H5F_ACC_SWMR_READ)
                         *intent_flags |= H5F_ACC_SWMR_READ;
-                }
+                } /* end else */
 
                 break;
             }
@@ -1581,7 +1628,7 @@ H5VL__native_file_get(void *obj, H5VL_file_get_t get_type,
                     HDstrncpy(name, H5F_OPEN_NAME(f), MIN(len + 1,size));
                     if(len >= size)
                         name[size-1]='\0';
-                }
+                } /* end if */
 
                 /* Set the return value for the API call */
                 *ret = (ssize_t)len;
@@ -2370,6 +2417,77 @@ done:
 
 
 /*-------------------------------------------------------------------------
+ * Function:    H5VL__native_group_optional
+ *
+ * Purpose:     Perform a connector-specific operation on a native group
+ *
+ * Return:      SUCCEED/FAIL
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+H5VL__native_group_optional(void *obj, hid_t H5_ATTR_UNUSED dxpl_id,
+    void H5_ATTR_UNUSED **req, va_list arguments)
+{
+    H5VL_group_optional_t optional_type;
+    herr_t ret_value = SUCCEED;    /* Return value */
+
+    FUNC_ENTER_STATIC
+
+    optional_type = va_arg(arguments, H5VL_group_optional_t);
+    switch(optional_type) {
+#ifndef H5_NO_DEPRECATED_SYMBOLS
+        /* H5Giterate (deprecated) */
+        case H5VL_GROUP_ITERATE_OLD:
+            {
+                H5VL_loc_params_t loc_params = va_arg(arguments, H5VL_loc_params_t);
+                hsize_t idx = va_arg(arguments, hsize_t);
+                hsize_t *last_obj = va_arg(arguments, hsize_t *);
+                const H5G_link_iterate_t *lnk_op = va_arg(arguments, const H5G_link_iterate_t *);
+                void *op_data = va_arg(arguments, void *);
+                H5G_loc_t grp_loc;
+
+                /* Get the location struct for the object */
+                if(H5G_loc_real(obj, loc_params.obj_type, &grp_loc) < 0)
+                    HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not a file or file object")
+
+                /* Call the actual iteration routine */
+                if((ret_value = H5G_iterate(&grp_loc, loc_params.loc_data.loc_by_name.name, H5_INDEX_NAME, H5_ITER_INC, idx, last_obj, lnk_op, op_data)) < 0)
+                    HERROR(H5E_VOL, H5E_BADITER, "error iterating over group's links");
+
+                break;
+            }
+
+        /* H5Gget_objinfo (deprecated) */
+        case H5VL_GROUP_GET_OBJINFO:
+            {
+                H5VL_loc_params_t loc_params = va_arg(arguments, H5VL_loc_params_t);
+                hbool_t follow_link = va_arg(arguments, unsigned);
+                H5G_stat_t *statbuf = va_arg(arguments, H5G_stat_t *);
+                H5G_loc_t grp_loc;
+
+                /* Get the location struct for the object */
+                if(H5G_loc_real(obj, loc_params.obj_type, &grp_loc) < 0)
+                    HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not a file or file object")
+
+                /* Call the actual group objinfo routine */
+                if(H5G__get_objinfo(&grp_loc, loc_params.loc_data.loc_by_name.name, follow_link, statbuf) < 0)
+                    HGOTO_ERROR(H5E_SYM, H5E_CANTGET, FAIL, "cannot stat object")
+
+                break;
+            }
+#endif /* H5_NO_DEPRECATED_SYMBOLS */
+
+        default:
+            HGOTO_ERROR(H5E_VOL, H5E_UNSUPPORTED, FAIL, "invalid optional operation")
+    } /* end switch */
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5VL__native_group_optional() */
+
+
+/*-------------------------------------------------------------------------
  * Function:    H5VL__native_group_close
  *
  * Purpose:     Closes a group.
@@ -2655,13 +2773,12 @@ H5VL__native_link_get(void *obj, H5VL_loc_params_t loc_params, H5VL_link_get_t g
                 if(loc_params.type == H5VL_OBJECT_BY_NAME) { /* H5Lget_info */
                     if(H5L_get_info(&loc, loc_params.loc_data.loc_by_name.name, linfo) < 0)
                         HGOTO_ERROR(H5E_LINK, H5E_NOTFOUND, FAIL, "unable to get link info")
-                }
+                } /* end if */
                 else if(loc_params.type == H5VL_OBJECT_BY_IDX) { /* H5Lget_info_by_idx */
-
                     if(H5L_get_info_by_idx(&loc, loc_params.loc_data.loc_by_idx.name, loc_params.loc_data.loc_by_idx.idx_type,
                             loc_params.loc_data.loc_by_idx.order, loc_params.loc_data.loc_by_idx.n, linfo) < 0)
                         HGOTO_ERROR(H5E_LINK, H5E_NOTFOUND, FAIL, "unable to get link info")
-                }
+                } /* end else-if */
                 else
                     HGOTO_ERROR(H5E_LINK, H5E_NOTFOUND, FAIL, "unable to get link info")
                 break;
@@ -3018,6 +3135,20 @@ H5VL__native_object_get(void *obj, H5VL_loc_params_t loc_params, H5VL_object_get
                 break;
             }
 
+        /* H5Iget_name */
+        case H5VL_ID_GET_NAME:
+            {
+                ssize_t *ret = va_arg(arguments, ssize_t *);
+                char *name = va_arg(arguments, char *);
+                size_t size = va_arg(arguments, size_t);
+
+                /* Retrieve object's name */
+                if((*ret = H5G_get_name(&loc, name, size, NULL)) < 0)
+                    HGOTO_ERROR(H5E_ATOM, H5E_CANTGET, FAIL, "can't retrieve object name")
+
+                break;
+            }
+
         default:
             HGOTO_ERROR(H5E_VOL, H5E_CANTGET, FAIL, "can't get this type of information from object")
     } /* end switch */
@@ -3222,7 +3353,7 @@ H5VL__native_object_optional(void *obj, hid_t H5_ATTR_UNUSED dxpl_id,
                         HGOTO_ERROR(H5E_OHDR, H5E_CANTRELEASE, FAIL, "can't free location")
                 } /* end else-if */
                 else
-                    HGOTO_ERROR(H5E_VOL, H5E_UNSUPPORTED, FAIL, "unknown get info parameters")
+                    HGOTO_ERROR(H5E_OHDR, H5E_UNSUPPORTED, FAIL, "unknown get info parameters")
                 break;
             }
 
diff --git a/src/H5VLpublic.h b/src/H5VLpublic.h
index 95c3d11..7049930 100644
--- a/src/H5VLpublic.h
+++ b/src/H5VLpublic.h
@@ -162,9 +162,10 @@ typedef enum H5VL_link_specific_t {
 
 /* types for object GET callback */
 typedef enum H5VL_object_get_t {
-    H5VL_REF_GET_NAME,                 /* object name                       */
+    H5VL_REF_GET_NAME,                 /* object name, for reference        */
     H5VL_REF_GET_REGION,               /* dataspace of region               */
-    H5VL_REF_GET_TYPE                  /* type of object                    */
+    H5VL_REF_GET_TYPE,                 /* type of object                    */
+    H5VL_ID_GET_NAME                   /* object name, for hid_t            */
 } H5VL_object_get_t;
 
 /* types for object SPECIFIC callback */
diff --git a/src/H5trace.c b/src/H5trace.c
index 797130e..de63c4c 100644
--- a/src/H5trace.c
+++ b/src/H5trace.c
@@ -2893,6 +2893,9 @@ H5_trace(const double *returning, const char *func, const char *type, ...)
                                 case H5VL_REF_GET_NAME:
                                     HDfprintf(out, "H5VL_REF_GET_NAME");
                                     break;
+                                case H5VL_ID_GET_NAME:
+                                    HDfprintf(out, "H5VL_ID_GET_NAME");
+                                    break;
                                 default:
                                     HDfprintf(out, "%ld", (long)get);
                                     break;