Merge branch 'develop' into feature/coding_standardsfeature/coding_standards

1 files changed, 1604 insertions, 411 deletions

diff --git a/src/H5O.c b/src/H5O.c
index bf2d799..0ffa3e0 100644
--- a/src/H5O.c
+++ b/src/H5O.c
@@ -6,7 +6,7 @@
  * This file is part of HDF5.  The full HDF5 copyright notice, including     *
  * terms governing use, modification, and redistribution, is contained in    *
  * the COPYING file, which can be found at the root of the source code       *
- * distribution tree, or in https://support.hdfgroup.org/ftp/HDF5/releases.  *
+ * distribution tree, or in https://www.hdfgroup.org/licenses.               *
  * If you do not have access to either file, you may request a copy from     *
  * help@hdfgroup.org.                                                        *
  * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
@@ -24,58 +24,110 @@
 /* Module Setup */
 /****************/
 
-#include "H5Omodule.h"          /* This source code file is part of the H5O module */
-
+#include "H5Omodule.h" /* This source code file is part of the H5O module */
 
 /***********/
 /* Headers */
 /***********/
-#include "H5private.h"          /* Generic Functions                        */
-#include "H5CXprivate.h"        /* API Contexts                             */
-#include "H5Eprivate.h"         /* Error handling                           */
-#include "H5Fprivate.h"         /* File access                              */
-#include "H5Iprivate.h"         /* IDs                                      */
-#include "H5Lprivate.h"         /* Links                                    */
-#include "H5Opkg.h"             /* Object headers                           */
+#include "H5private.h"   /* Generic Functions                        */
+#include "H5CXprivate.h" /* API Contexts                             */
+#include "H5Eprivate.h"  /* Error handling                           */
+#include "H5ESprivate.h" /* Event Sets                               */
+#include "H5Fprivate.h"  /* File access                              */
+#include "H5Iprivate.h"  /* IDs                                      */
+#include "H5Lprivate.h"  /* Links                                    */
+#include "H5Opkg.h"      /* Object headers                           */
 
 #include "H5VLnative_private.h" /* Native VOL connector                     */
 
-
 /****************/
 /* Local Macros */
 /****************/
 
-
 /******************/
 /* Local Typedefs */
 /******************/
 
-
 /********************/
 /* Package Typedefs */
 /********************/
 
-
 /********************/
 /* Local Prototypes */
 /********************/
 
+/* Helper routines for sync/async API calls */
+static hid_t  H5O__open_api_common(hid_t loc_id, const char *name, hid_t lapl_id, void **token_ptr,
+                                   H5VL_object_t **_vol_obj_ptr);
+static hid_t  H5O__open_by_idx_api_common(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, void **token_ptr,
+                                          H5VL_object_t **_vol_obj_ptr);
+static herr_t H5O__get_info_by_name_api_common(hid_t loc_id, const char *name, H5O_info2_t *oinfo /*out*/,
+                                               unsigned fields, hid_t lapl_id, void **token_ptr,
+                                               H5VL_object_t **_vol_obj_ptr);
+static herr_t H5O__copy_api_common(hid_t src_loc_id, const char *src_name, hid_t dst_loc_id,
+                                   const char *dst_name, hid_t ocpypl_id, hid_t lcpl_id, void **token_ptr,
+                                   H5VL_object_t **_vol_obj_ptr);
+static herr_t H5O__flush_api_common(hid_t obj_id, void **token_ptr, H5VL_object_t **_vol_obj_ptr);
+static herr_t H5O__refresh_api_common(hid_t oid, void **token_ptr, H5VL_object_t **_vol_obj_ptr);
+static htri_t H5O__close_check_type(hid_t object_id);
 
 /*********************/
 /* Package Variables */
 /*********************/
 
-
 /*****************************/
 /* Library Private Variables */
 /*****************************/
 
-
 /*******************/
 /* Local Variables */
 /*******************/
 
-
+/*-------------------------------------------------------------------------
+ * Function:    H5O__open_api_common
+ *
+ * Purpose:     This is the common function for opening an object
+ *
+ * Return:      Success:    An open object identifier
+ *              Failure:    H5I_INVALID_HID
+ *
+ *-------------------------------------------------------------------------
+ */
+static hid_t
+H5O__open_api_common(hid_t loc_id, const char *name, hid_t lapl_id, void **token_ptr,
+                     H5VL_object_t **_vol_obj_ptr)
+{
+    H5VL_object_t * tmp_vol_obj = NULL; /* Object for loc_id */
+    H5VL_object_t **vol_obj_ptr =
+        (_vol_obj_ptr ? _vol_obj_ptr : &tmp_vol_obj); /* Ptr to object ptr for loc_id */
+    H5I_type_t        opened_type;
+    void *            opened_obj = NULL;
+    H5VL_loc_params_t loc_params;
+    hid_t             ret_value = H5I_INVALID_HID;
+
+    FUNC_ENTER_PACKAGE
+
+    /* Check args */
+
+    /* name is checked in this H5VL_setup_name_args() */
+    /* Set up object access arguments */
+    if (H5VL_setup_name_args(loc_id, name, FALSE, lapl_id, vol_obj_ptr, &loc_params) < 0)
+        HGOTO_ERROR(H5E_OHDR, H5E_CANTSET, H5I_INVALID_HID, "can't set object access arguments")
+
+    /* Open the object */
+    if (NULL == (opened_obj = H5VL_object_open(*vol_obj_ptr, &loc_params, &opened_type,
+                                               H5P_DATASET_XFER_DEFAULT, token_ptr)))
+        HGOTO_ERROR(H5E_OHDR, H5E_CANTOPENOBJ, H5I_INVALID_HID, "unable to open object")
+
+    /* Get an atom for the object */
+    if ((ret_value = H5VL_register(opened_type, opened_obj, (*vol_obj_ptr)->connector, TRUE)) < 0)
+        HGOTO_ERROR(H5E_OHDR, H5E_CANTREGISTER, H5I_INVALID_HID, "unable to atomize object handle")
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* H5O__open_api_common() */
+
 /*-------------------------------------------------------------------------
  * Function:    H5Oopen
  *
@@ -102,48 +154,108 @@
 hid_t
 H5Oopen(hid_t loc_id, const char *name, hid_t lapl_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;
-    hid_t           ret_value   = H5I_INVALID_HID;
+    hid_t ret_value = H5I_INVALID_HID;
 
     FUNC_ENTER_API(H5I_INVALID_HID)
     H5TRACE3("i", "i*si", loc_id, name, lapl_id);
 
-    /* Check args */
-    if(!name)
-        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, H5I_INVALID_HID, "name parameter cannot be NULL")
-    if(!*name)
-        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, H5I_INVALID_HID, "name parameter cannot be an empty string")
+    /* Open the object synchronously */
+    if ((ret_value = H5O__open_api_common(loc_id, name, lapl_id, NULL, NULL)) < 0)
+        HGOTO_ERROR(H5E_OHDR, H5E_CANTOPENOBJ, H5I_INVALID_HID, "unable to synchronously open object")
 
-    /* Verify access property list and set up collective metadata if appropriate */
-    if(H5CX_set_apl(&lapl_id, H5P_CLS_LACC, loc_id, FALSE) < 0)
-        HGOTO_ERROR(H5E_OHDR, H5E_CANTSET, H5I_INVALID_HID, "can't set access property list info")
+done:
+    FUNC_LEAVE_API(ret_value)
+} /* end H5Oopen() */
 
-    /* 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")
+/*-------------------------------------------------------------------------
+ * Function:    H5Oopen_async
+ *
+ * Purpose:     Asynchronous version of H5Oopen
+ *
+ * Return:      Success:    An open object identifier
+ *              Failure:    H5I_INVALID_HID
+ *
+ *-------------------------------------------------------------------------
+ */
+hid_t
+H5Oopen_async(const char *app_file, const char *app_func, unsigned app_line, hid_t loc_id, const char *name,
+              hid_t lapl_id, hid_t es_id)
+{
+    H5VL_object_t *vol_obj   = NULL;            /* Object for loc_id */
+    void *         token     = NULL;            /* Request token for async operation        */
+    void **        token_ptr = H5_REQUEST_NULL; /* Pointer to request token for async operation        */
+    hid_t          ret_value = H5I_INVALID_HID; /* Return value */
 
-    /* Set 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 = lapl_id;
-    loc_params.obj_type                     = H5I_get_type(loc_id);
+    FUNC_ENTER_API(H5I_INVALID_HID)
+    H5TRACE7("i", "*s*sIui*sii", app_file, app_func, app_line, loc_id, name, lapl_id, es_id);
+
+    /* Set up request token pointer for asynchronous operation */
+    if (H5ES_NONE != es_id)
+        token_ptr = &token; /* Point at token for VOL connector to set up */
+
+    /* Open the object asynchronously */
+    if ((ret_value = H5O__open_api_common(loc_id, name, lapl_id, token_ptr, &vol_obj)) < 0)
+        HGOTO_ERROR(H5E_OHDR, H5E_CANTOPENOBJ, H5I_INVALID_HID, "unable to asynchronously open object")
+
+    /* If a token was created, add the token to the event set */
+    if (NULL != token)
+        /* clang-format off */
+        if (H5ES_insert(es_id, vol_obj->connector, token,
+                        H5ARG_TRACE7(__func__, "*s*sIui*sii", app_file, app_func, app_line, loc_id, name, lapl_id, es_id)) < 0) {
+            /* clang-format on */
+            if (H5I_dec_app_ref_always_close(ret_value) < 0)
+                HDONE_ERROR(H5E_OHDR, H5E_CANTDEC, H5I_INVALID_HID, "can't decrement count on object ID")
+            HGOTO_ERROR(H5E_OHDR, H5E_CANTINSERT, H5I_INVALID_HID, "can't insert token into event set")
+        }
+
+done:
+    FUNC_LEAVE_API(ret_value)
+} /* end H5Oopen_async() */
+
+/*-------------------------------------------------------------------------
+ * Function:    H5O__open_by_idx_api_common
+ *
+ * Purpose:     This is the common function for opening an object within an index
+ *
+ * Return:      Success:    An open object identifier
+ *              Failure:    H5I_INVALID_HID
+ *
+ *-------------------------------------------------------------------------
+ */
+static hid_t
+H5O__open_by_idx_api_common(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, void **token_ptr, H5VL_object_t **_vol_obj_ptr)
+{
+    H5VL_object_t * tmp_vol_obj = NULL; /* Object for loc_id */
+    H5VL_object_t **vol_obj_ptr =
+        (_vol_obj_ptr ? _vol_obj_ptr : &tmp_vol_obj); /* Ptr to object ptr for loc_id */
+    H5I_type_t        opened_type;
+    void *            opened_obj = NULL;
+    H5VL_loc_params_t loc_params;
+    hid_t             ret_value = H5I_INVALID_HID;
+
+    FUNC_ENTER_PACKAGE
+
+    /* Check args */
+    /* group_name, idx_type, order are checked in H5VL_setup_idx-args() */
+    /* Set up object access arguments */
+    if (H5VL_setup_idx_args(loc_id, group_name, idx_type, order, n, FALSE, lapl_id, vol_obj_ptr,
+                            &loc_params) < 0)
+        HGOTO_ERROR(H5E_LINK, H5E_CANTSET, H5I_INVALID_HID, "can't set object access arguments")
 
     /* Open the object */
-    if(NULL == (opened_obj = H5VL_object_open(vol_obj, &loc_params, &opened_type, H5P_DATASET_XFER_DEFAULT, H5_REQUEST_NULL)))
+    if (NULL == (opened_obj = H5VL_object_open(*vol_obj_ptr, &loc_params, &opened_type,
+                                               H5P_DATASET_XFER_DEFAULT, token_ptr)))
         HGOTO_ERROR(H5E_OHDR, H5E_CANTOPENOBJ, H5I_INVALID_HID, "unable to open object")
 
-    /* Get an atom for the object */
-    if((ret_value = H5VL_register(opened_type, opened_obj, vol_obj->connector, TRUE)) < 0)
-        HGOTO_ERROR(H5E_OHDR, H5E_CANTREGISTER, H5I_INVALID_HID, "unable to atomize object handle")
+    /* Get an ID for the object */
+    if ((ret_value = H5VL_register(opened_type, opened_obj, (*vol_obj_ptr)->connector, TRUE)) < 0)
+        HGOTO_ERROR(H5E_OHDR, H5E_CANTREGISTER, H5I_INVALID_HID, "unable to register object handle")
 
 done:
-    FUNC_LEAVE_API(ret_value)
-} /* end H5Oopen() */
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* H5O__open_by_idx_api_common() */
 
-
 /*-------------------------------------------------------------------------
  * Function:	H5Oopen_by_idx
  *
@@ -168,122 +280,540 @@ done:
  *-------------------------------------------------------------------------
  */
 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)
+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;             /* Object token of loc_id */
-    H5I_type_t opened_type;
-    void *opened_obj = NULL;
-    H5VL_loc_params_t loc_params;
     hid_t ret_value = H5I_INVALID_HID;
 
     FUNC_ENTER_API(H5I_INVALID_HID)
     H5TRACE6("i", "i*sIiIohi", loc_id, group_name, idx_type, order, n, lapl_id);
 
-    /* Check args */
-    if(!group_name || !*group_name)
-        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, H5I_INVALID_HID, "no name specified")
-    if(idx_type <= H5_INDEX_UNKNOWN || idx_type >= H5_INDEX_N)
-        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, H5I_INVALID_HID, "invalid index type specified")
-    if(order <= H5_ITER_UNKNOWN || order >= H5_ITER_N)
-        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, H5I_INVALID_HID, "invalid iteration order specified")
-
-    /* Verify access property list and set up collective metadata if appropriate */
-    if(H5CX_set_apl(&lapl_id, H5P_CLS_LACC, loc_id, FALSE) < 0)
-        HGOTO_ERROR(H5E_OHDR, H5E_CANTSET, H5I_INVALID_HID, "can't set access property list info")
-
-    loc_params.type = H5VL_OBJECT_BY_IDX;
-    loc_params.loc_data.loc_by_idx.name = group_name;
-    loc_params.loc_data.loc_by_idx.idx_type = idx_type;
-    loc_params.loc_data.loc_by_idx.order = order;
-    loc_params.loc_data.loc_by_idx.n = n;
-    loc_params.loc_data.loc_by_idx.lapl_id = lapl_id;
-    loc_params.obj_type = H5I_get_type(loc_id);
+    /* Open the object synchronously */
+    if ((ret_value =
+             H5O__open_by_idx_api_common(loc_id, group_name, idx_type, order, n, lapl_id, NULL, NULL)) < 0)
+        HGOTO_ERROR(H5E_OHDR, H5E_CANTOPENOBJ, H5I_INVALID_HID, "unable to synchronously open 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")
+done:
+    FUNC_LEAVE_API(ret_value)
+} /* end H5Oopen_by_idx() */
 
-    /* Open the object */
-    if(NULL == (opened_obj = H5VL_object_open(vol_obj, &loc_params, &opened_type, H5P_DATASET_XFER_DEFAULT, H5_REQUEST_NULL)))
-        HGOTO_ERROR(H5E_OHDR, H5E_CANTOPENOBJ, H5I_INVALID_HID, "unable to open object")
+/*-------------------------------------------------------------------------
+ * Function:    H5Oopen_by_idx_async
+ *
+ * Purpose:     Asynchronous version of H5Oopen_by_idx
+ *
+ * Return:      Success:    An open object identifier
+ *              Failure:    H5I_INVALID_HID
+ *
+ *-------------------------------------------------------------------------
+ */
+hid_t
+H5Oopen_by_idx_async(const char *app_file, const char *app_func, unsigned app_line, 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, hid_t es_id)
+{
+    H5VL_object_t *vol_obj   = NULL;            /* Object for loc_id */
+    void *         token     = NULL;            /* Request token for async operation        */
+    void **        token_ptr = H5_REQUEST_NULL; /* Pointer to request token for async operation        */
+    hid_t          ret_value = H5I_INVALID_HID; /* Return value */
 
-    if((ret_value = H5VL_register(opened_type, opened_obj, vol_obj->connector, TRUE)) < 0)
-        HGOTO_ERROR(H5E_OHDR, H5E_CANTREGISTER, H5I_INVALID_HID, "unable to atomize object handle")
+    FUNC_ENTER_API(H5I_INVALID_HID)
+    H5TRACE10("i", "*s*sIui*sIiIohii", app_file, app_func, app_line, loc_id, group_name, idx_type, order, n,
+              lapl_id, es_id);
+
+    /* Set up request token pointer for asynchronous operation */
+    if (H5ES_NONE != es_id)
+        token_ptr = &token; /* Point at token for VOL connector to set up */
+
+    /* Open the object asynchronously */
+    if ((ret_value = H5O__open_by_idx_api_common(loc_id, group_name, idx_type, order, n, lapl_id, token_ptr,
+                                                 &vol_obj)) < 0)
+        HGOTO_ERROR(H5E_OHDR, H5E_CANTOPENOBJ, H5I_INVALID_HID, "unable to asynchronously open object")
+
+    /* If a token was created, add the token to the event set */
+    if (NULL != token)
+        /* clang-format off */
+        if (H5ES_insert(es_id, vol_obj->connector, token,
+                        H5ARG_TRACE10(__func__, "*s*sIui*sIiIohii", app_file, app_func, app_line, loc_id, group_name, idx_type, order, n, lapl_id, es_id)) < 0) {
+            /* clang-format on */
+            if (H5I_dec_app_ref_always_close(ret_value) < 0)
+                HDONE_ERROR(H5E_OHDR, H5E_CANTDEC, H5I_INVALID_HID, "can't decrement count on object ID")
+            HGOTO_ERROR(H5E_OHDR, H5E_CANTINSERT, H5I_INVALID_HID, "can't insert token into event set")
+        }
 
 done:
     FUNC_LEAVE_API(ret_value)
-} /* end H5Oopen_by_idx() */
+} /* end H5Oopen_by_idx_async() */
 
-
 /*-------------------------------------------------------------------------
- * Function:	H5Oopen_by_addr
+ * Function:    H5Oopen_by_token
  *
- * Purpose:	Warning! This function is EXTREMELY DANGEROUS!
- *              Improper use can lead to FILE CORRUPTION, INACCESSIBLE DATA,
- *              and other VERY BAD THINGS!
+ * Purpose:     Same as H5Oopen_by_addr, but uses VOL-independent tokens.
  *
- *              This function opens an object using its address within the
- *              HDF5 file, similar to an HDF5 hard link. The open object
- *              is identical to an object opened with H5Oopen() and should
- *              be closed with H5Oclose() or a type-specific closing
- *              function (such as H5Gclose() ).
- *
- *              This function is very dangerous if called on an invalid
- *              address. For this reason, H5Oincr_refcount() should be
- *              used to prevent HDF5 from deleting any object that is
- *              referenced by address (e.g. by a user-defined link).
- *              H5Odecr_refcount() should be used when the object is
- *              no longer being referenced by address (e.g. when the UD link
- *              is deleted).
- *
- *              The address of the HDF5 file on disk has no effect on
- *              H5Oopen_by_addr(), nor does the use of any unusual file
- *              drivers. The "address" is really the offset within the
- *              HDF5 file, and HDF5's file drivers will transparently
- *              map this to an address on disk for the filesystem.
- *
- * Return:	Success:	An open object identifier
- *		Failure:	H5I_INVALID_HID
+ * Return:      Success:    An open object identifier
+ *              Failure:    H5I_INVALID_HID
  *
- * Programmer:	James Laird
- *		July 14 2006
+ * Programmer:  Dana Robinson
+ *              Winter 2019
  *
  *-------------------------------------------------------------------------
  */
 hid_t
-H5Oopen_by_addr(hid_t loc_id, haddr_t addr)
+H5Oopen_by_token(hid_t loc_id, H5O_token_t token)
 {
-    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;
-    hid_t       ret_value = H5I_INVALID_HID;	/* Return value */
+    H5VL_object_t *   vol_obj;                     /* Object of loc_id */
+    H5I_type_t        vol_obj_type = H5I_BADID;    /* Object type of loc_id */
+    H5I_type_t        opened_type;                 /* Opened object type */
+    void *            opened_obj = NULL;           /* Opened object */
+    H5VL_loc_params_t loc_params;                  /* Location parameters */
+    hid_t             ret_value = H5I_INVALID_HID; /* Return value */
 
     FUNC_ENTER_API(H5I_INVALID_HID)
-    H5TRACE2("i", "ia", loc_id, addr);
+    H5TRACE2("i", "ik", loc_id, token);
 
-    loc_params.type = H5VL_OBJECT_BY_ADDR;
-    loc_params.loc_data.loc_by_addr.addr = addr;
-    loc_params.obj_type = H5I_get_type(loc_id);
+    /* Check args */
+    if (H5O_IS_TOKEN_UNDEF(token))
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, H5I_INVALID_HID, "can't open H5O_TOKEN_UNDEF")
 
     /* 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, H5I_INVALID_HID, "invalid location identifier")
 
+    /* Get object type */
+    if ((vol_obj_type = H5I_get_type(loc_id)) < 0)
+        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, H5I_INVALID_HID, "invalid location identifier")
+
+    loc_params.type                        = H5VL_OBJECT_BY_TOKEN;
+    loc_params.loc_data.loc_by_token.token = &token;
+    loc_params.obj_type                    = vol_obj_type;
+
     /* Open the object */
-    if(NULL == (opened_obj = H5VL_object_open(vol_obj, &loc_params, &opened_type, H5P_DATASET_XFER_DEFAULT, H5_REQUEST_NULL)))
+    if (NULL == (opened_obj = H5VL_object_open(vol_obj, &loc_params, &opened_type, H5P_DATASET_XFER_DEFAULT,
+                                               H5_REQUEST_NULL)))
         HGOTO_ERROR(H5E_OHDR, H5E_CANTOPENOBJ, H5I_INVALID_HID, "unable to open object")
 
-    /* Register the dataset ID */
-    if((ret_value = H5VL_register(opened_type, opened_obj, vol_obj->connector, TRUE)) < 0)
-        HGOTO_ERROR(H5E_OHDR, H5E_CANTREGISTER, H5I_INVALID_HID, "unable to atomize object handle")
+    /* Register the object's ID */
+    if ((ret_value = H5VL_register(opened_type, opened_obj, vol_obj->connector, TRUE)) < 0)
+        HGOTO_ERROR(H5E_OHDR, H5E_CANTREGISTER, H5I_INVALID_HID, "unable to register object handle")
+
+done:
+    FUNC_LEAVE_API(ret_value)
+} /* end H5Oopen_by_token() */
+
+/*-------------------------------------------------------------------------
+ * Function:    H5O__copy_api_common
+ *
+ * Purpose:     This is the common function for copying an object.
+ *
+ * Return:      SUCCEED/FAIL
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+H5O__copy_api_common(hid_t src_loc_id, const char *src_name, hid_t dst_loc_id, const char *dst_name,
+                     hid_t ocpypl_id, hid_t lcpl_id, void **token_ptr, H5VL_object_t **_vol_obj_ptr)
+{
+    /* dst_id */
+    H5VL_object_t * tmp_vol_obj = NULL; /* Object for loc_id */
+    H5VL_object_t **vol_obj_ptr =
+        (_vol_obj_ptr ? _vol_obj_ptr : &tmp_vol_obj); /* Ptr to object ptr for loc_id */
+    H5VL_loc_params_t loc_params2;
+
+    /* src_id */
+    H5VL_object_t *   vol_obj1 = NULL; /* object of src_id */
+    H5VL_loc_params_t loc_params1;
+
+    herr_t ret_value = SUCCEED; /* Return value */
+
+    FUNC_ENTER_PACKAGE
+
+    /* Check arguments */
+    if (!src_name || !*src_name)
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "no source name specified")
+    if (!dst_name || !*dst_name)
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "no destination name specified")
+
+    /* Get correct property lists */
+    if (H5P_DEFAULT == lcpl_id)
+        lcpl_id = H5P_LINK_CREATE_DEFAULT;
+    else if (TRUE != H5P_isa_class(lcpl_id, H5P_LINK_CREATE))
+        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not link creation property list")
+
+    /* Get object copy property list */
+    if (H5P_DEFAULT == ocpypl_id)
+        ocpypl_id = H5P_OBJECT_COPY_DEFAULT;
+    else if (TRUE != H5P_isa_class(ocpypl_id, H5P_OBJECT_COPY))
+        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not object copy property list")
+
+    /* Set the LCPL for the API context */
+    H5CX_set_lcpl(lcpl_id);
+
+    /* Setup and check args */
+    if (H5VL_setup_loc_args(src_loc_id, &vol_obj1, &loc_params1) < 0)
+        HGOTO_ERROR(H5E_OHDR, H5E_CANTSET, FAIL, "can't set object access arguments")
+
+    /* get the object */
+    if (NULL == (*vol_obj_ptr = (H5VL_object_t *)H5I_object(dst_loc_id)))
+        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "invalid location identifier")
+    loc_params2.type     = H5VL_OBJECT_BY_SELF;
+    loc_params2.obj_type = H5I_get_type(dst_loc_id);
+
+    /* Copy the object */
+    if (H5VL_object_copy(vol_obj1, &loc_params1, src_name, *vol_obj_ptr, &loc_params2, dst_name, ocpypl_id,
+                         lcpl_id, H5P_DATASET_XFER_DEFAULT, token_ptr) < 0)
+        HGOTO_ERROR(H5E_OHDR, H5E_CANTCOPY, FAIL, "unable to copy object")
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* H5O__copy_api_common() */
+
+/*-------------------------------------------------------------------------
+ * Function:    H5Ocopy
+ *
+ * Purpose:     Copy an object (group or dataset) to destination location
+ *              within a file or cross files. PLIST_ID is a property list
+ *              which is used to pass user options and properties to the
+ *              copy. The name, dst_name, must not already be taken by some
+ *              other object in the destination group.
+ *
+ *              H5Ocopy() will fail if the name of the destination object
+ *                  exists in the destination group.  For example,
+ *                  H5Ocopy(fid_src, "/dset", fid_dst, "/dset", ...)
+ *                  will fail if "/dset" exists in the destination file
+ *
+ *              OPTIONS THAT HAVE BEEN IMPLEMENTED.
+ *                  H5O_COPY_SHALLOW_HIERARCHY_FLAG
+ *                      If this flag is specified, only immediate members of
+ *                      the group are copied. Otherwise (default), it will
+ *                      recursively copy all objects below the group
+ *                  H5O_COPY_EXPAND_SOFT_LINK_FLAG
+ *                      If this flag is specified, it will copy the objects
+ *                      pointed by the soft links. Otherwise (default), it
+ *                      will copy the soft link as they are
+ *                  H5O_COPY_WITHOUT_ATTR_FLAG
+ *                      If this flag is specified, it will copy object without
+ *                      copying attributes. Otherwise (default), it will
+ *                      copy object along with all its attributes
+ *                  H5O_COPY_EXPAND_REFERENCE_FLAG
+ *                      1) Copy object between two different files:
+ *                          When this flag is specified, it will copy objects that
+ *                          are pointed by the references and update the values of
+ *                          references in the destination file.  Otherwise (default)
+ *                          the values of references in the destination will set to
+ *                          zero
+ *                          The current implementation does not handle references
+ *                          inside of other datatype structure. For example, if
+ *                          a member of compound datatype is reference, H5Ocopy()
+ *                          will copy that field as it is. It will not set the
+ *                          value to zero as default is used nor copy the object
+ *                          pointed by that field the flag is set
+ *                      2) Copy object within the same file:
+ *                          This flag does not have any effect to the H5Ocopy().
+ *                          Datasets or attributes of references are copied as they
+ *                          are, i.e. values of references of the destination object
+ *                          are the same as the values of the source object
+ *
+ *              OPTIONS THAT MAY APPLY TO COPY IN THE FUTURE.
+ *                  H5O_COPY_EXPAND_EXT_LINK_FLAG
+ *                      If this flag is specified, it will expand the external links
+ *                      into new objects, Otherwise (default), it will keep external
+ *                      links as they are (default)
+ *
+ *              PROPERTIES THAT MAY APPLY TO COPY IN FUTURE
+ *                  Change data layout such as chunk size
+ *                  Add filter such as data compression.
+ *                  Add an attribute to the copied object(s) that say the  date/time
+ *                      for the copy or other information about the source file.
+ *
+ *              The intermediate group creation property should be passed in
+ *              using the lcpl instead of the ocpypl.
+ *
+ * Usage:      H5Ocopy(src_loc_id, src_name, dst_loc_id, dst_name, ocpypl_id, lcpl_id)
+ *             hid_t src_loc_id         IN: Source file or group identifier.
+ *             const char *src_name     IN: Name of the source object to be copied
+ *             hid_t dst_loc_id         IN: Destination file or group identifier
+ *             const char *dst_name     IN: Name of the destination object
+ *             hid_t ocpypl_id          IN: Properties which apply to the copy
+ *             hid_t lcpl_id            IN: Properties which apply to the new hard link
+ *
+ *
+ * Return:      SUCCEED/FAIL
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5Ocopy(hid_t src_loc_id, const char *src_name, hid_t dst_loc_id, const char *dst_name, hid_t ocpypl_id,
+        hid_t lcpl_id)
+{
+    herr_t ret_value = SUCCEED; /* Return value */
+
+    FUNC_ENTER_API(FAIL)
+    H5TRACE6("e", "i*si*sii", src_loc_id, src_name, dst_loc_id, dst_name, ocpypl_id, lcpl_id);
+
+    /* To copy an object synchronously */
+    if (H5O__copy_api_common(src_loc_id, src_name, dst_loc_id, dst_name, ocpypl_id, lcpl_id, NULL, NULL) < 0)
+        HGOTO_ERROR(H5E_OHDR, H5E_CANTCOPY, FAIL, "unable to synchronously copy object")
+
+done:
+    FUNC_LEAVE_API(ret_value)
+} /* end H5Ocopy() */
+
+/*-------------------------------------------------------------------------
+ * Function:    H5Ocopy_async
+ *
+ * Purpose:     Asynchronous version of H5Ocopy
+ *
+ * Return:      SUCCEED/FAIL
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5Ocopy_async(const char *app_file, const char *app_func, unsigned app_line, hid_t src_loc_id,
+              const char *src_name, hid_t dst_loc_id, const char *dst_name, hid_t ocpypl_id, hid_t lcpl_id,
+              hid_t es_id)
+{
+    H5VL_object_t *vol_obj   = NULL;            /* Object for loc_id */
+    void *         token     = NULL;            /* Request token for async operation        */
+    void **        token_ptr = H5_REQUEST_NULL; /* Pointer to request token for async operation        */
+    herr_t         ret_value = SUCCEED;         /* Return value */
+
+    FUNC_ENTER_API(FAIL)
+    H5TRACE10("e", "*s*sIui*si*siii", app_file, app_func, app_line, src_loc_id, src_name, dst_loc_id,
+              dst_name, ocpypl_id, lcpl_id, es_id);
+
+    /* Set up request token pointer for asynchronous operation */
+    if (H5ES_NONE != es_id)
+        token_ptr = &token; /* Point at token for VOL connector to set up */
+
+    /* To copy an object asynchronously */
+    if (H5O__copy_api_common(src_loc_id, src_name, dst_loc_id, dst_name, ocpypl_id, lcpl_id, token_ptr,
+                             &vol_obj) < 0)
+        HGOTO_ERROR(H5E_OHDR, H5E_CANTCOPY, FAIL, "unable to asynchronously copy object")
+
+    /* If a token was created, add the token to the event set */
+    if (NULL != token)
+        /* clang-format off */
+        if (H5ES_insert(es_id, vol_obj->connector, token,
+                        H5ARG_TRACE10(__func__, "*s*sIui*si*siii", app_file, app_func, app_line, src_loc_id, src_name, dst_loc_id, dst_name, ocpypl_id, lcpl_id, es_id)) < 0)
+            /* clang-format on */
+            HGOTO_ERROR(H5E_OHDR, H5E_CANTINSERT, FAIL, "can't insert token into event set")
+
+done:
+    FUNC_LEAVE_API(ret_value)
+} /* H5Ocopy_async() */
+
+/*-------------------------------------------------------------------------
+ * Function:    H5O__flush_api_common
+ *
+ * Purpose:     This is the common function for flushing an object.
+ *
+ * Return:      SUCCEED/FAIL
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+H5O__flush_api_common(hid_t obj_id, void **token_ptr, H5VL_object_t **_vol_obj_ptr)
+{
+    H5VL_object_t * tmp_vol_obj = NULL; /* Object for loc_id */
+    H5VL_object_t **vol_obj_ptr =
+        (_vol_obj_ptr ? _vol_obj_ptr : &tmp_vol_obj); /* Ptr to object ptr for loc_id */
+    H5VL_object_specific_args_t vol_cb_args;          /* Arguments to VOL callback */
+    H5VL_loc_params_t           loc_params;           /* Location parameters for object access */
+    herr_t                      ret_value = SUCCEED;  /* Return value */
+
+    FUNC_ENTER_PACKAGE
+
+    /* Setup and check args */
+    if (H5VL_setup_loc_args(obj_id, vol_obj_ptr, &loc_params) < 0)
+        HGOTO_ERROR(H5E_OHDR, H5E_CANTSET, FAIL, "can't set object access arguments")
+
+    /* Set up VOL callback arguments */
+    vol_cb_args.op_type           = H5VL_OBJECT_FLUSH;
+    vol_cb_args.args.flush.obj_id = obj_id;
+
+    /* Flush the object */
+    if (H5VL_object_specific(*vol_obj_ptr, &loc_params, &vol_cb_args, H5P_DATASET_XFER_DEFAULT, token_ptr) <
+        0)
+        HGOTO_ERROR(H5E_OHDR, H5E_CANTFLUSH, FAIL, "unable to flush object")
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* H5O__flush_api_common() */
+
+/*-------------------------------------------------------------------------
+ * Function:    H5Oflush
+ *
+ * Purpose:     Flushes all buffers associated with an object to disk.
+ *
+ * Return:      Non-negative on success, negative on failure
+ *
+ * Programmer:  Mike McGreevy
+ *              May 19, 2010
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5Oflush(hid_t obj_id)
+{
+    herr_t ret_value = SUCCEED; /* Return value     */
+
+    FUNC_ENTER_API(FAIL)
+    H5TRACE1("e", "i", obj_id);
+
+    /* To flush an object synchronously */
+    if (H5O__flush_api_common(obj_id, NULL, NULL) < 0)
+        HGOTO_ERROR(H5E_OHDR, H5E_CANTFLUSH, FAIL, "unable to synchronously flush object")
+
+done:
+    FUNC_LEAVE_API(ret_value)
+} /* end H5Oflush() */
+
+/*-------------------------------------------------------------------------
+ * Function:    H5Oflush_async
+ *
+ * Purpose:     Asynchronous version of H5Oflush
+ *
+ * Return:      SUCCEED/FAIL
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5Oflush_async(const char *app_file, const char *app_func, unsigned app_line, hid_t obj_id, hid_t es_id)
+{
+    H5VL_object_t *vol_obj   = NULL;            /* Object for loc_id */
+    void *         token     = NULL;            /* Request token for async operation        */
+    void **        token_ptr = H5_REQUEST_NULL; /* Pointer to request token for async operation        */
+    herr_t         ret_value = SUCCEED;         /* Return value */
+
+    FUNC_ENTER_API(FAIL)
+    H5TRACE5("e", "*s*sIuii", app_file, app_func, app_line, obj_id, es_id);
+
+    /* Set up request token pointer for asynchronous operation */
+    if (H5ES_NONE != es_id)
+        token_ptr = &token; /* Point at token for VOL connector to set up */
+
+    /* Flush an object asynchronously */
+    if (H5O__flush_api_common(obj_id, token_ptr, &vol_obj) < 0)
+        HGOTO_ERROR(H5E_OHDR, H5E_CANTFLUSH, FAIL, "unable to asynchronously flush object")
+
+    /* If a token was created, add the token to the event set */
+    if (NULL != token)
+        /* clang-format off */
+        if (H5ES_insert(es_id, vol_obj->connector, token,
+                        H5ARG_TRACE5(__func__, "*s*sIuii", app_file, app_func, app_line, obj_id, es_id)) < 0)
+            /* clang-format on */
+            HGOTO_ERROR(H5E_OHDR, H5E_CANTINSERT, FAIL, "can't insert token into event set")
+
+done:
+    FUNC_LEAVE_API(ret_value)
+} /* H5Oflush_async() */
+
+/*-------------------------------------------------------------------------
+ * Function:    H5O__refresh_api_common
+ *
+ * Purpose:     This is the common function for refreshing an object.
+ *
+ * Return:      SUCCEED/FAIL
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+H5O__refresh_api_common(hid_t oid, void **token_ptr, H5VL_object_t **_vol_obj_ptr)
+{
+    H5VL_object_t * tmp_vol_obj = NULL; /* Object for loc_id */
+    H5VL_object_t **vol_obj_ptr =
+        (_vol_obj_ptr ? _vol_obj_ptr : &tmp_vol_obj); /* Ptr to object ptr for loc_id */
+    H5VL_object_specific_args_t vol_cb_args;          /* Arguments to VOL callback */
+    H5VL_loc_params_t           loc_params;           /* Location parameters for object access */
+    herr_t                      ret_value = SUCCEED;  /* Return value */
+
+    FUNC_ENTER_PACKAGE
+
+    /* Setup and check args */
+    if (H5VL_setup_loc_args(oid, vol_obj_ptr, &loc_params) < 0)
+        HGOTO_ERROR(H5E_OHDR, H5E_CANTSET, FAIL, "can't set object access arguments")
+
+    /* Set up VOL callback arguments */
+    vol_cb_args.op_type             = H5VL_OBJECT_REFRESH;
+    vol_cb_args.args.refresh.obj_id = oid;
+
+    /* Refresh the object */
+    if (H5VL_object_specific(*vol_obj_ptr, &loc_params, &vol_cb_args, H5P_DATASET_XFER_DEFAULT, token_ptr) <
+        0)
+        HGOTO_ERROR(H5E_OHDR, H5E_CANTLOAD, FAIL, "unable to refresh object")
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* H5O__refresh_api_common() */
+
+/*-------------------------------------------------------------------------
+ * Function:    H5Orefresh
+ *
+ * Purpose:     Refreshes all buffers associated with an object.
+ *
+ * Return:      Non-negative on success, negative on failure
+ *
+ * Programmer:  Mike McGreevy
+ *              July 28, 2010
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5Orefresh(hid_t oid)
+{
+    herr_t ret_value = SUCCEED; /* Return value     */
+
+    FUNC_ENTER_API(FAIL)
+    H5TRACE1("e", "i", oid);
+
+    /* To refresh an object synchronously */
+    if (H5O__refresh_api_common(oid, NULL, NULL) < 0)
+        HGOTO_ERROR(H5E_OHDR, H5E_CANTLOAD, FAIL, "unable to synchronously refresh object")
 
 done:
     FUNC_LEAVE_API(ret_value)
-} /* end H5Oopen_by_addr() */
+} /* end H5Orefresh() */
+
+/*-------------------------------------------------------------------------
+ * Function:    H5Orefresh_async
+ *
+ * Purpose:     Asynchronous version of H5Orefresh
+ *
+ * Return:      SUCCEED/FAIL
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5Orefresh_async(const char *app_file, const char *app_func, unsigned app_line, hid_t oid, hid_t es_id)
+{
+    H5VL_object_t *vol_obj   = NULL;            /* Object for loc_id */
+    void *         token     = NULL;            /* Request token for async operation        */
+    void **        token_ptr = H5_REQUEST_NULL; /* Pointer to request token for async operation        */
+    herr_t         ret_value = SUCCEED;         /* Return value */
+
+    FUNC_ENTER_API(FAIL)
+    H5TRACE5("e", "*s*sIuii", app_file, app_func, app_line, oid, es_id);
+
+    /* Set up request token pointer for asynchronous operation */
+    if (H5ES_NONE != es_id)
+        token_ptr = &token; /* Point at token for VOL connector to set up */
+
+    /* Refresh an object asynchronously */
+    if (H5O__refresh_api_common(oid, token_ptr, &vol_obj) < 0)
+        HGOTO_ERROR(H5E_OHDR, H5E_CANTLOAD, FAIL, "unable to asynchronously refresh object")
+
+    /* If a token was created, add the token to the event set */
+    if (NULL != token)
+        /* clang-format off */
+        if (H5ES_insert(es_id, vol_obj->connector, token,
+                        H5ARG_TRACE5(__func__, "*s*sIuii", app_file, app_func, app_line, oid, es_id)) < 0)
+            /* clang-format on */
+            HGOTO_ERROR(H5E_OHDR, H5E_CANTINSERT, FAIL, "can't insert token into event set")
+
+done:
+    FUNC_LEAVE_API(ret_value)
+} /* H5Orefresh_async() */
 
-
 /*-------------------------------------------------------------------------
  * Function:	H5Olink
  *
@@ -306,75 +836,88 @@ done:
  *-------------------------------------------------------------------------
  */
 herr_t
-H5Olink(hid_t obj_id, hid_t new_loc_id, const char *new_name, hid_t lcpl_id,
-    hid_t lapl_id)
+H5Olink(hid_t obj_id, hid_t new_loc_id, const char *new_name, hid_t lcpl_id, hid_t lapl_id)
 {
-    H5VL_object_t    *vol_obj1 = NULL;        /* object token of obj_id */
-    H5VL_object_t    *vol_obj2 = NULL;        /* object token of new_loc_id */
-    H5VL_object_t     tmp_vol_obj;            /* Temporary object token of */
-    H5VL_loc_params_t loc_params1;
-    H5VL_loc_params_t loc_params2;
-    herr_t         ret_value = SUCCEED;       /* Return value */
+    H5VL_object_t *         vol_obj1 = NULL; /* object of obj_id */
+    H5VL_object_t *         vol_obj2 = NULL; /* object of new_loc_id */
+    H5VL_object_t           tmp_vol_obj;     /* Temporary object */
+    H5VL_link_create_args_t vol_cb_args;     /* Arguments to VOL callback */
+    H5VL_loc_params_t       new_loc_params;
+    herr_t                  ret_value = SUCCEED; /* Return value */
 
     FUNC_ENTER_API(FAIL)
     H5TRACE5("e", "ii*sii", obj_id, new_loc_id, new_name, lcpl_id, lapl_id);
 
     /* Check arguments */
-    if(new_loc_id == H5L_SAME_LOC)
-        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "cannot use H5L_SAME_LOC when only one location is specified")
-    if(!new_name || !*new_name)
+    if (new_loc_id == H5L_SAME_LOC)
+        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL,
+                    "cannot use H5L_SAME_LOC when only one location is specified")
+    if (!new_name || !*new_name)
         HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "no name specified")
 /* Avoid compiler warning on 32-bit machines */
 #if H5_SIZEOF_SIZE_T > H5_SIZEOF_INT32_T
-    if(HDstrlen(new_name) > H5L_MAX_LINK_NAME_LEN)
+    if (HDstrlen(new_name) > H5L_MAX_LINK_NAME_LEN)
         HGOTO_ERROR(H5E_ARGS, H5E_BADRANGE, FAIL, "name too long")
 #endif /* H5_SIZEOF_SIZE_T > H5_SIZEOF_INT32_T */
-    if(lcpl_id != H5P_DEFAULT && (TRUE != H5P_isa_class(lcpl_id, H5P_LINK_CREATE)))
+    if (lcpl_id != H5P_DEFAULT && (TRUE != H5P_isa_class(lcpl_id, H5P_LINK_CREATE)))
         HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not a link creation property list")
 
-    /* Check the group access property list */
-    if(H5P_DEFAULT == lcpl_id)
+    /* Get the link creation property list */
+    if (H5P_DEFAULT == lcpl_id)
         lcpl_id = H5P_LINK_CREATE_DEFAULT;
 
+    /* Set the LCPL for the API context */
+    H5CX_set_lcpl(lcpl_id);
+
     /* Verify access property list and set up collective metadata if appropriate */
-    if(H5CX_set_apl(&lapl_id, H5P_CLS_LACC, obj_id, TRUE) < 0)
+    if (H5CX_set_apl(&lapl_id, H5P_CLS_LACC, obj_id, TRUE) < 0)
         HGOTO_ERROR(H5E_OHDR, H5E_CANTSET, FAIL, "can't set access property list info")
 
-    loc_params1.type = H5VL_OBJECT_BY_SELF;
-    loc_params1.obj_type = H5I_get_type(obj_id);
-
-    loc_params2.type = H5VL_OBJECT_BY_NAME;
-    loc_params2.obj_type = H5I_get_type(new_loc_id);
-    loc_params2.loc_data.loc_by_name.name = new_name;
-    loc_params2.loc_data.loc_by_name.lapl_id = lapl_id;
+    /* Set up new location struct */
+    new_loc_params.type                         = H5VL_OBJECT_BY_NAME;
+    new_loc_params.obj_type                     = H5I_get_type(new_loc_id);
+    new_loc_params.loc_data.loc_by_name.name    = new_name;
+    new_loc_params.loc_data.loc_by_name.lapl_id = lapl_id;
 
-    if(H5L_SAME_LOC != obj_id)
-        /* get the location object */
-        if(NULL == (vol_obj1 = H5VL_vol_object(obj_id)))
-            HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "invalid location identifier")
-    if(H5L_SAME_LOC != new_loc_id)
+    /* Get the first location object */
+    if (NULL == (vol_obj1 = H5VL_vol_object(obj_id)))
+        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "invalid location identifier")
+    if (H5L_SAME_LOC != new_loc_id)
         /* get the location object */
-        if(NULL == (vol_obj2 = H5VL_vol_object(new_loc_id)))
+        if (NULL == (vol_obj2 = H5VL_vol_object(new_loc_id)))
             HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "invalid location identifier")
 
     /* Make sure that the VOL connectors are the same */
-    if(vol_obj1 && vol_obj2)
-        if (vol_obj1->connector->cls->value != vol_obj2->connector->cls->value)
-            HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "Objects are accessed through different VOL connectors and can't be linked")
+    if (vol_obj1 && vol_obj2) {
+        int same_connector = 0;
+
+        /* Check if both objects are associated with the same VOL connector */
+        if (H5VL_cmp_connector_cls(&same_connector, vol_obj1->connector->cls, vol_obj2->connector->cls) < 0)
+            HGOTO_ERROR(H5E_FILE, H5E_CANTCOMPARE, FAIL, "can't compare connector classes")
+        if (same_connector)
+            HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL,
+                        "Objects are accessed through different VOL connectors and can't be linked")
+    } /* end if */
 
     /* Construct a temporary VOL object */
-    tmp_vol_obj.data = vol_obj2->data;
-    tmp_vol_obj.connector = (vol_obj1 != NULL ? vol_obj1->connector : vol_obj2->connector);
+    tmp_vol_obj.data      = vol_obj2->data;
+    tmp_vol_obj.connector = vol_obj1->connector;
+
+    /* Set up VOL callback arguments */
+    vol_cb_args.op_type                            = H5VL_LINK_CREATE_HARD;
+    vol_cb_args.args.hard.curr_obj                 = vol_obj1->data;
+    vol_cb_args.args.hard.curr_loc_params.type     = H5VL_OBJECT_BY_SELF;
+    vol_cb_args.args.hard.curr_loc_params.obj_type = H5I_get_type(obj_id);
 
     /* Create a link to the object */
-    if(H5VL_link_create(H5VL_LINK_CREATE_HARD, &tmp_vol_obj, &loc_params2, lcpl_id, lapl_id, H5P_DATASET_XFER_DEFAULT, H5_REQUEST_NULL, vol_obj1->data, &loc_params1) < 0)
+    if (H5VL_link_create(&vol_cb_args, &tmp_vol_obj, &new_loc_params, lcpl_id, lapl_id,
+                         H5P_DATASET_XFER_DEFAULT, H5_REQUEST_NULL) < 0)
         HGOTO_ERROR(H5E_OHDR, H5E_CANTCREATE, FAIL, "unable to create link")
 
 done:
     FUNC_LEAVE_API(ret_value)
 } /* end H5Olink() */
 
-
 /*-------------------------------------------------------------------------
  * Function:	H5Oincr_refcount
  *
@@ -398,33 +941,38 @@ done:
 herr_t
 H5Oincr_refcount(hid_t object_id)
 {
-    H5VL_object_t *vol_obj;             /* Object token of loc_id */
-    H5VL_loc_params_t loc_params;
-    herr_t      ret_value = SUCCEED;
+    H5VL_object_t *             vol_obj;     /* Object of loc_id */
+    H5VL_object_specific_args_t vol_cb_args; /* Arguments to VOL callback */
+    H5VL_loc_params_t           loc_params;  /* Location parameters for object access */
+    herr_t                      ret_value = SUCCEED;
 
     FUNC_ENTER_API(FAIL)
     H5TRACE1("e", "i", object_id);
 
-    loc_params.type = H5VL_OBJECT_BY_SELF;
+    loc_params.type     = H5VL_OBJECT_BY_SELF;
     loc_params.obj_type = H5I_get_type(object_id);
 
     /* Get the location object */
-    if(NULL == (vol_obj = H5VL_vol_object(object_id)))
+    if (NULL == (vol_obj = H5VL_vol_object(object_id)))
         HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "invalid location identifier")
 
     /* Set up collective metadata if appropriate */
-    if(H5CX_set_loc(object_id) < 0)
+    if (H5CX_set_loc(object_id) < 0)
         HGOTO_ERROR(H5E_OHDR, H5E_CANTSET, FAIL, "can't set access property list info")
 
+    /* Set up VOL callback arguments */
+    vol_cb_args.op_type              = H5VL_OBJECT_CHANGE_REF_COUNT;
+    vol_cb_args.args.change_rc.delta = 1;
+
     /* Change the object's reference count */
-    if(H5VL_object_specific(vol_obj, &loc_params, H5VL_OBJECT_CHANGE_REF_COUNT, H5P_DATASET_XFER_DEFAULT, H5_REQUEST_NULL, 1) < 0)
+    if (H5VL_object_specific(vol_obj, &loc_params, &vol_cb_args, H5P_DATASET_XFER_DEFAULT, H5_REQUEST_NULL) <
+        0)
         HGOTO_ERROR(H5E_OHDR, H5E_LINKCOUNT, FAIL, "modifying object link count failed")
 
 done:
     FUNC_LEAVE_API(ret_value)
 } /* end H5O_incr_refcount() */
 
-
 /*-------------------------------------------------------------------------
  * Function:	H5Odecr_refcount
  *
@@ -448,33 +996,38 @@ done:
 herr_t
 H5Odecr_refcount(hid_t object_id)
 {
-    H5VL_object_t *vol_obj;             /* Object token of loc_id */
-    H5VL_loc_params_t loc_params;
-    herr_t      ret_value = SUCCEED;	/* Return value */
+    H5VL_object_t *             vol_obj;             /* Object of loc_id */
+    H5VL_object_specific_args_t vol_cb_args;         /* Arguments to VOL callback */
+    H5VL_loc_params_t           loc_params;          /* Location parameters for object access */
+    herr_t                      ret_value = SUCCEED; /* Return value */
 
     FUNC_ENTER_API(FAIL)
     H5TRACE1("e", "i", object_id);
 
-    loc_params.type = H5VL_OBJECT_BY_SELF;
+    loc_params.type     = H5VL_OBJECT_BY_SELF;
     loc_params.obj_type = H5I_get_type(object_id);
 
     /* Get the location object */
-    if(NULL == (vol_obj = H5VL_vol_object(object_id)))
+    if (NULL == (vol_obj = H5VL_vol_object(object_id)))
         HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "invalid location identifier")
 
     /* Set up collective metadata if appropriate */
-    if(H5CX_set_loc(object_id) < 0)
+    if (H5CX_set_loc(object_id) < 0)
         HGOTO_ERROR(H5E_OHDR, H5E_CANTSET, FAIL, "can't set access property list info")
 
+    /* Set up VOL callback arguments */
+    vol_cb_args.op_type              = H5VL_OBJECT_CHANGE_REF_COUNT;
+    vol_cb_args.args.change_rc.delta = -1;
+
     /* Change the object's reference count */
-    if(H5VL_object_specific(vol_obj, &loc_params, H5VL_OBJECT_CHANGE_REF_COUNT, H5P_DATASET_XFER_DEFAULT, H5_REQUEST_NULL, -1) < 0)
+    if (H5VL_object_specific(vol_obj, &loc_params, &vol_cb_args, H5P_DATASET_XFER_DEFAULT, H5_REQUEST_NULL) <
+        0)
         HGOTO_ERROR(H5E_OHDR, H5E_LINKCOUNT, FAIL, "modifying object link count failed")
 
 done:
     FUNC_LEAVE_API(ret_value)
 } /* end H5Odecr_refcount() */
 
-
 /*-------------------------------------------------------------------------
  * Function:    H5Oexists_by_name
  *
@@ -491,25 +1044,27 @@ done:
 htri_t
 H5Oexists_by_name(hid_t loc_id, const char *name, hid_t lapl_id)
 {
-    H5VL_object_t *vol_obj;             /* Object token of loc_id */
-    H5VL_loc_params_t loc_params;
-    htri_t      ret_value = FAIL;       /* Return value */
+    H5VL_object_t *             vol_obj;            /* Object of loc_id */
+    H5VL_object_specific_args_t vol_cb_args;        /* Arguments to VOL callback */
+    H5VL_loc_params_t           loc_params;         /* Location parameters for object access */
+    hbool_t                     obj_exists = FALSE; /* Whether object exists */
+    htri_t                      ret_value  = FAIL;  /* Return value */
 
     FUNC_ENTER_API(FAIL)
     H5TRACE3("t", "i*si", loc_id, name, lapl_id);
 
     /* Check args */
-    if(!name)
+    if (!name)
         HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "name parameter cannot be NULL")
-    if(!*name)
+    if (!*name)
         HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "name parameter cannot be an empty string")
 
     /* Verify access property list and set up collective metadata if appropriate */
-    if(H5CX_set_apl(&lapl_id, H5P_CLS_LACC, loc_id, FALSE) < 0)
+    if (H5CX_set_apl(&lapl_id, H5P_CLS_LACC, loc_id, FALSE) < 0)
         HGOTO_ERROR(H5E_OHDR, H5E_CANTSET, FAIL, "can't set access property list info")
 
     /* Get the location object */
-    if(NULL == (vol_obj = H5VL_vol_object(loc_id)))
+    if (NULL == (vol_obj = H5VL_vol_object(loc_id)))
         HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "invalid location identifier")
 
     /* Set the location struct fields */
@@ -518,99 +1073,349 @@ H5Oexists_by_name(hid_t loc_id, const char *name, hid_t lapl_id)
     loc_params.loc_data.loc_by_name.lapl_id = lapl_id;
     loc_params.obj_type                     = H5I_get_type(loc_id);
 
+    /* Set up VOL callback arguments */
+    vol_cb_args.op_type            = H5VL_OBJECT_EXISTS;
+    vol_cb_args.args.exists.exists = &obj_exists;
+
     /* Check if the object exists */
-    if(H5VL_object_specific(vol_obj, &loc_params, H5VL_OBJECT_EXISTS, H5P_DATASET_XFER_DEFAULT, H5_REQUEST_NULL, &ret_value) < 0)
+    if (H5VL_object_specific(vol_obj, &loc_params, &vol_cb_args, H5P_DATASET_XFER_DEFAULT, H5_REQUEST_NULL) <
+        0)
         HGOTO_ERROR(H5E_OHDR, H5E_CANTGET, FAIL, "unable to determine if '%s' exists", name)
 
+    /* Set return value */
+    ret_value = (htri_t)obj_exists;
+
 done:
     FUNC_LEAVE_API(ret_value)
 } /* end H5Oexists_by_name() */
 
-
 /*-------------------------------------------------------------------------
- * Function:    H5Oget_info2
+ * Function:    H5Oget_info3
  *
  * Purpose:     Retrieve information about an object.
  *
- *              NOTE: Add a parameter "fields" to indicate selection of object info.
- *
  * Return:      SUCCEED/FAIL
  *
- * Programmer:  Neil Fortner
- *              July 7 2010
+ * Programmer:  Dana Robinson
+ *              Fall 2019
  *
  *-------------------------------------------------------------------------
  */
 herr_t
-H5Oget_info2(hid_t loc_id, H5O_info_t *oinfo, unsigned fields)
+H5Oget_info3(hid_t loc_id, H5O_info2_t *oinfo /*out*/, unsigned fields)
 {
-    H5VL_object_t *vol_obj;             /* Object token of loc_id */
-    H5VL_loc_params_t   loc_params;
-    herr_t      ret_value = SUCCEED;    /* Return value */
+    H5VL_object_t *        vol_obj;     /* Object of loc_id */
+    H5VL_object_get_args_t vol_cb_args; /* Arguments to VOL callback */
+    H5VL_loc_params_t      loc_params;
+    herr_t                 ret_value = SUCCEED; /* Return value */
 
     FUNC_ENTER_API(FAIL)
-    H5TRACE3("e", "i*xIu", loc_id, oinfo, fields);
+    H5TRACE3("e", "ixIu", loc_id, oinfo, fields);
 
     /* Check args */
-    if(!oinfo)
+    if (!oinfo)
         HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "oinfo parameter cannot be NULL")
-    if(fields & ~H5O_INFO_ALL)
+    if (fields & ~H5O_INFO_ALL)
         HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "invalid fields")
 
     /* Set location struct fields */
-    loc_params.type         = H5VL_OBJECT_BY_SELF;
-    loc_params.obj_type     = H5I_get_type(loc_id);
+    loc_params.type     = H5VL_OBJECT_BY_SELF;
+    loc_params.obj_type = H5I_get_type(loc_id);
 
     /* Get the location object */
-    if(NULL == (vol_obj = H5VL_vol_object(loc_id)))
+    if (NULL == (vol_obj = H5VL_vol_object(loc_id)))
         HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "invalid location identifier")
 
+    /* Set up VOL callback arguments */
+    vol_cb_args.op_type              = H5VL_OBJECT_GET_INFO;
+    vol_cb_args.args.get_info.oinfo  = oinfo;
+    vol_cb_args.args.get_info.fields = fields;
+
     /* Retrieve the object's information */
-    if(H5VL_object_optional(vol_obj, H5P_DATASET_XFER_DEFAULT, H5_REQUEST_NULL, H5VL_NATIVE_OBJECT_GET_INFO, &loc_params, oinfo, fields) < 0)
-        HGOTO_ERROR(H5E_OHDR, H5E_CANTGET, FAIL, "can't get info for object")
+    if (H5VL_object_get(vol_obj, &loc_params, &vol_cb_args, H5P_DATASET_XFER_DEFAULT, H5_REQUEST_NULL) < 0)
+        HGOTO_ERROR(H5E_OHDR, H5E_CANTGET, FAIL, "can't get data model info for object")
 
 done:
     FUNC_LEAVE_API(ret_value)
-} /* end H5Oget_info2() */
+} /* end H5Oget_info3() */
 
-
 /*-------------------------------------------------------------------------
- * Function:    H5Oget_info_by_name2
+ * Function:    H5O__get_info_by_name_api_common
+ *
+ * Purpose:     This is the common function for retrieving information
+ *              about an object.
+ *
+ * Return:      SUCCEED/FAIL
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+H5O__get_info_by_name_api_common(hid_t loc_id, const char *name, H5O_info2_t *oinfo /*out*/, unsigned fields,
+                                 hid_t lapl_id, void **token_ptr, H5VL_object_t **_vol_obj_ptr)
+{
+    H5VL_object_t * tmp_vol_obj = NULL; /* Object for loc_id */
+    H5VL_object_t **vol_obj_ptr =
+        (_vol_obj_ptr ? _vol_obj_ptr : &tmp_vol_obj); /* Ptr to object ptr for loc_id */
+    H5VL_object_get_args_t vol_cb_args;               /* Arguments to VOL callback */
+    H5VL_loc_params_t      loc_params;                /* Location parameters for object access */
+    herr_t                 ret_value = SUCCEED;       /* Return value */
+
+    FUNC_ENTER_PACKAGE
+
+    /* Check args */
+    if (!oinfo)
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "oinfo parameter cannot be NULL")
+    if (fields & ~H5O_INFO_ALL)
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "invalid fields")
+
+    /* "name" is checked in H5VL_setup_name_args() */
+    /* Set up object access arguments */
+    if (H5VL_setup_name_args(loc_id, name, FALSE, lapl_id, vol_obj_ptr, &loc_params) < 0)
+        HGOTO_ERROR(H5E_OHDR, H5E_CANTSET, FAIL, "can't set object access arguments")
+
+    /* Set up VOL callback arguments */
+    vol_cb_args.op_type              = H5VL_OBJECT_GET_INFO;
+    vol_cb_args.args.get_info.oinfo  = oinfo;
+    vol_cb_args.args.get_info.fields = fields;
+
+    /* Retrieve the object's information */
+    if (H5VL_object_get(*vol_obj_ptr, &loc_params, &vol_cb_args, H5P_DATASET_XFER_DEFAULT, token_ptr) < 0)
+        HGOTO_ERROR(H5E_OHDR, H5E_CANTGET, FAIL, "can't get data model info for object")
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* H5O__get_info_by_name_api_common() */
+
+/*-------------------------------------------------------------------------
+ * Function:    H5Oget_info_by_name3
  *
  * Purpose:     Retrieve information about an object
  *
- *              NOTE: Add a parameter "fields" to indicate selection of object info.
+ * Return:      SUCCEED/FAIL
+ *
+ * Programmer:  Dana Robinson
+ *              Fall 2019
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5Oget_info_by_name3(hid_t loc_id, const char *name, H5O_info2_t *oinfo /*out*/, unsigned fields,
+                     hid_t lapl_id)
+{
+    herr_t ret_value = SUCCEED; /* Return value */
+
+    FUNC_ENTER_API(FAIL)
+    H5TRACE5("e", "i*sxIui", loc_id, name, oinfo, fields, lapl_id);
+
+    /* Retrieve object information synchronously */
+    if (H5O__get_info_by_name_api_common(loc_id, name, oinfo, fields, lapl_id, NULL, NULL) < 0)
+        HGOTO_ERROR(H5E_OHDR, H5E_CANTGET, FAIL, "can't synchronously retrieve object info")
+
+done:
+    FUNC_LEAVE_API(ret_value)
+} /* end H5Oget_info_by_name3() */
+
+/*-------------------------------------------------------------------------
+ * Function:    H5Oget_info_by_name_async
+ *
+ * Purpose:     Asynchronous version of H5Oget_info_by_name3
  *
  * Return:      SUCCEED/FAIL
  *
- * Programmer:  Neil Fortner
- *              July 7 2010
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5Oget_info_by_name_async(const char *app_file, const char *app_func, unsigned app_line, hid_t loc_id,
+                          const char *name, H5O_info2_t *oinfo /*out*/, unsigned fields, hid_t lapl_id,
+                          hid_t es_id)
+{
+    H5VL_object_t *vol_obj   = NULL;            /* Object for loc_id */
+    void *         token     = NULL;            /* Request token for async operation */
+    void **        token_ptr = H5_REQUEST_NULL; /* Pointer to request token for async operation */
+    herr_t         ret_value = SUCCEED;         /* Return value */
+
+    FUNC_ENTER_API(FAIL)
+    H5TRACE9("e", "*s*sIui*sxIuii", app_file, app_func, app_line, loc_id, name, oinfo, fields, lapl_id,
+             es_id);
+
+    /* Set up request token pointer for asynchronous operation */
+    if (H5ES_NONE != es_id)
+        token_ptr = &token; /* Point at token for VOL connector to set up */
+
+    /* Retrieve group information asynchronously */
+    if (H5O__get_info_by_name_api_common(loc_id, name, oinfo, fields, lapl_id, token_ptr, &vol_obj) < 0)
+        HGOTO_ERROR(H5E_OHDR, H5E_CANTGET, FAIL, "can't asynchronously retrieve object info")
+
+    /* If a token was created, add the token to the event set */
+    if (NULL != token)
+        /* clang-format off */
+        if (H5ES_insert(es_id, vol_obj->connector, token,
+                        H5ARG_TRACE9(__func__, "*s*sIui*sxIuii", app_file, app_func, app_line, loc_id, name, oinfo, fields, lapl_id, es_id)) < 0)
+            /* clang-format on */
+            HGOTO_ERROR(H5E_OHDR, H5E_CANTINSERT, FAIL, "can't insert token into event set")
+
+done:
+    FUNC_LEAVE_API(ret_value)
+} /* H5Oget_info_by_name_async() */
+
+/*-------------------------------------------------------------------------
+ * Function:    H5Oget_info_by_idx3
+ *
+ * Purpose:     Retrieve information about an object, according to
+ *              the order of an index.
+ *
+ * Return:      Success:	Non-negative
+ *              Failure:	Negative
+ *
+ * Programmer:	Dana Robinson
+ *              Fall 2019
  *
  *-------------------------------------------------------------------------
  */
 herr_t
-H5Oget_info_by_name2(hid_t loc_id, const char *name, H5O_info_t *oinfo,
-    unsigned fields, hid_t lapl_id)
+H5Oget_info_by_idx3(hid_t loc_id, const char *group_name, H5_index_t idx_type, H5_iter_order_t order,
+                    hsize_t n, H5O_info2_t *oinfo /*out*/, unsigned fields, hid_t lapl_id)
 {
-    H5VL_object_t *vol_obj;             /* Object token of loc_id */
-    H5VL_loc_params_t loc_params;
-    herr_t      ret_value = SUCCEED;    /* Return value */
+    H5VL_object_t *        vol_obj;     /* Object of loc_id */
+    H5VL_object_get_args_t vol_cb_args; /* Arguments to VOL callback */
+    H5VL_loc_params_t      loc_params;
+    herr_t                 ret_value = SUCCEED; /* Return value */
+
+    FUNC_ENTER_API(FAIL)
+    H5TRACE8("e", "i*sIiIohxIui", loc_id, group_name, idx_type, order, n, oinfo, fields, lapl_id);
+
+    /* Check args */
+    if (!group_name || !*group_name)
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "no name specified")
+    if (idx_type <= H5_INDEX_UNKNOWN || idx_type >= H5_INDEX_N)
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "invalid index type specified")
+    if (order <= H5_ITER_UNKNOWN || order >= H5_ITER_N)
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "invalid iteration order specified")
+    if (!oinfo)
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "no info struct")
+    if (fields & ~H5O_INFO_ALL)
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "invalid fields")
+
+    /* Verify access property list and set up collective metadata if appropriate */
+    if (H5CX_set_apl(&lapl_id, H5P_CLS_LACC, loc_id, FALSE) < 0)
+        HGOTO_ERROR(H5E_OHDR, H5E_CANTSET, FAIL, "can't set access property list info")
+
+    /* Set location struct fields */
+    loc_params.type                         = H5VL_OBJECT_BY_IDX;
+    loc_params.loc_data.loc_by_idx.name     = group_name;
+    loc_params.loc_data.loc_by_idx.idx_type = idx_type;
+    loc_params.loc_data.loc_by_idx.order    = order;
+    loc_params.loc_data.loc_by_idx.n        = n;
+    loc_params.loc_data.loc_by_idx.lapl_id  = lapl_id;
+    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 up VOL callback arguments */
+    vol_cb_args.op_type              = H5VL_OBJECT_GET_INFO;
+    vol_cb_args.args.get_info.oinfo  = oinfo;
+    vol_cb_args.args.get_info.fields = fields;
+
+    /* Retrieve the object's information */
+    if (H5VL_object_get(vol_obj, &loc_params, &vol_cb_args, H5P_DATASET_XFER_DEFAULT, H5_REQUEST_NULL) < 0)
+        HGOTO_ERROR(H5E_OHDR, H5E_CANTGET, FAIL, "can't get data model info for object")
+
+done:
+    FUNC_LEAVE_API(ret_value)
+} /* end H5Oget_info_by_idx3() */
+
+/*-------------------------------------------------------------------------
+ * Function:    H5Oget_native_info
+ *
+ * Purpose:     Retrieve native file format information about an object.
+ *
+ * Return:      SUCCEED/FAIL
+ *
+ * Programmer:  Dana Robinson
+ *              Fall 2019
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5Oget_native_info(hid_t loc_id, H5O_native_info_t *oinfo /*out*/, unsigned fields)
+{
+    H5VL_object_t *                    vol_obj;      /* Object of loc_id */
+    H5VL_optional_args_t               vol_cb_args;  /* Arguments to VOL callback */
+    H5VL_native_object_optional_args_t obj_opt_args; /* Arguments for optional operation */
+    H5VL_loc_params_t                  loc_params;
+    herr_t                             ret_value = SUCCEED; /* Return value */
 
     FUNC_ENTER_API(FAIL)
-    H5TRACE5("e", "i*s*xIui", loc_id, name, oinfo, fields, lapl_id);
+    H5TRACE3("e", "ixIu", loc_id, oinfo, fields);
 
     /* Check args */
-    if(!name)
+    if (!oinfo)
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "oinfo parameter cannot be NULL")
+    if (fields & ~H5O_NATIVE_INFO_ALL)
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "invalid fields")
+
+    /* Set location struct fields */
+    loc_params.type     = H5VL_OBJECT_BY_SELF;
+    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 up VOL callback arguments */
+    obj_opt_args.get_native_info.fields = fields;
+    obj_opt_args.get_native_info.ninfo  = oinfo;
+    vol_cb_args.op_type                 = H5VL_NATIVE_OBJECT_GET_NATIVE_INFO;
+    vol_cb_args.args                    = &obj_opt_args;
+
+    /* Retrieve the object's information */
+    if (H5VL_object_optional(vol_obj, &loc_params, &vol_cb_args, H5P_DATASET_XFER_DEFAULT, H5_REQUEST_NULL) <
+        0)
+        HGOTO_ERROR(H5E_OHDR, H5E_CANTGET, FAIL, "can't get native file format info for object")
+
+done:
+    FUNC_LEAVE_API(ret_value)
+} /* end H5Oget_native_info() */
+
+/*-------------------------------------------------------------------------
+ * Function:    H5Oget_native_info_by_name
+ *
+ * Purpose:     Retrieve native file format information about an object
+ *
+ * Return:      SUCCEED/FAIL
+ *
+ * Programmer:  Dana Robinson
+ *              Fall 2019
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5Oget_native_info_by_name(hid_t loc_id, const char *name, H5O_native_info_t *oinfo /*out*/, unsigned fields,
+                           hid_t lapl_id)
+{
+    H5VL_object_t *                    vol_obj;      /* Object of loc_id */
+    H5VL_optional_args_t               vol_cb_args;  /* Arguments to VOL callback */
+    H5VL_native_object_optional_args_t obj_opt_args; /* Arguments for optional operation */
+    H5VL_loc_params_t                  loc_params;
+    herr_t                             ret_value = SUCCEED; /* Return value */
+
+    FUNC_ENTER_API(FAIL)
+    H5TRACE5("e", "i*sxIui", loc_id, name, oinfo, fields, lapl_id);
+
+    /* Check args */
+    if (!name)
         HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "name parameter cannot be NULL")
-    if(!*name)
+    if (!*name)
         HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "name parameter cannot be an empty string")
-    if(!oinfo)
+    if (!oinfo)
         HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "oinfo parameter cannot be NULL")
-    if(fields & ~H5O_INFO_ALL)
+    if (fields & ~H5O_NATIVE_INFO_ALL)
         HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "invalid fields")
 
     /* Verify access property list and set up collective metadata if appropriate */
-    if(H5CX_set_apl(&lapl_id, H5P_CLS_LACC, loc_id, FALSE) < 0)
+    if (H5CX_set_apl(&lapl_id, H5P_CLS_LACC, loc_id, FALSE) < 0)
         HGOTO_ERROR(H5E_OHDR, H5E_CANTSET, FAIL, "can't set access property list info")
 
     /* Fill out location struct */
@@ -620,83 +1425,95 @@ H5Oget_info_by_name2(hid_t loc_id, const char *name, H5O_info_t *oinfo,
     loc_params.obj_type                     = H5I_get_type(loc_id);
 
     /* Get the location object */
-    if(NULL == (vol_obj = H5VL_vol_object(loc_id)))
+    if (NULL == (vol_obj = H5VL_vol_object(loc_id)))
         HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "invalid location identifier")
 
+    /* Set up VOL callback arguments */
+    obj_opt_args.get_native_info.fields = fields;
+    obj_opt_args.get_native_info.ninfo  = oinfo;
+    vol_cb_args.op_type                 = H5VL_NATIVE_OBJECT_GET_NATIVE_INFO;
+    vol_cb_args.args                    = &obj_opt_args;
+
     /* Retrieve the object's information */
-    if(H5VL_object_optional(vol_obj, H5P_DATASET_XFER_DEFAULT, H5_REQUEST_NULL, H5VL_NATIVE_OBJECT_GET_INFO, &loc_params, oinfo, fields) < 0)
-        HGOTO_ERROR(H5E_OHDR, H5E_CANTGET, FAIL, "can't get info for object: '%s'", name)
+    if (H5VL_object_optional(vol_obj, &loc_params, &vol_cb_args, H5P_DATASET_XFER_DEFAULT, H5_REQUEST_NULL) <
+        0)
+        HGOTO_ERROR(H5E_OHDR, H5E_CANTGET, FAIL, "can't get native file format info for object: '%s'", name)
 
 done:
     FUNC_LEAVE_API(ret_value)
-} /* end H5Oget_info_by_name2() */
+} /* end H5Oget_native_info_by_name() */
 
-
 /*-------------------------------------------------------------------------
- * Function:    H5Oget_info_by_idx2
+ * Function:    H5Oget_native_info_by_idx
  *
- * Purpose:     Retrieve information about an object, according to the order
- *              of an index.
- *
- *              NOTE: Add a parameter "fields" to indicate selection of object info.
+ * Purpose:     Retrieve native file format information about an object,
+ *              according to the order of an index.
  *
  * Return:      Success:	Non-negative
  *              Failure:	Negative
  *
- * Programmer:	Quincey Koziol
- *              November 26 2006
+ * Programmer:	Dana Robinson
+ *              Fall 2019
  *
  *-------------------------------------------------------------------------
  */
 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)
+H5Oget_native_info_by_idx(hid_t loc_id, const char *group_name, H5_index_t idx_type, H5_iter_order_t order,
+                          hsize_t n, H5O_native_info_t *oinfo /*out*/, unsigned fields, hid_t lapl_id)
 {
-    H5VL_object_t *vol_obj;             /* Object token of loc_id */
-    H5VL_loc_params_t loc_params;
-    herr_t      ret_value = SUCCEED;    /* Return value */
+    H5VL_object_t *                    vol_obj;      /* Object of loc_id */
+    H5VL_optional_args_t               vol_cb_args;  /* Arguments to VOL callback */
+    H5VL_native_object_optional_args_t obj_opt_args; /* Arguments for optional operation */
+    H5VL_loc_params_t                  loc_params;
+    herr_t                             ret_value = SUCCEED; /* Return value */
 
     FUNC_ENTER_API(FAIL)
-    H5TRACE8("e", "i*sIiIoh*xIui", loc_id, group_name, idx_type, order, n, oinfo,
-             fields, lapl_id);
+    H5TRACE8("e", "i*sIiIohxIui", loc_id, group_name, idx_type, order, n, oinfo, fields, lapl_id);
 
     /* Check args */
-    if(!group_name || !*group_name)
+    if (!group_name || !*group_name)
         HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "no name specified")
-    if(idx_type <= H5_INDEX_UNKNOWN || idx_type >= H5_INDEX_N)
+    if (idx_type <= H5_INDEX_UNKNOWN || idx_type >= H5_INDEX_N)
         HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "invalid index type specified")
-    if(order <= H5_ITER_UNKNOWN || order >= H5_ITER_N)
+    if (order <= H5_ITER_UNKNOWN || order >= H5_ITER_N)
         HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "invalid iteration order specified")
-    if(!oinfo)
+    if (!oinfo)
         HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "no info struct")
-    if(fields & ~H5O_INFO_ALL)
+    if (fields & ~H5O_NATIVE_INFO_ALL)
         HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "invalid fields")
 
     /* Verify access property list and set up collective metadata if appropriate */
-    if(H5CX_set_apl(&lapl_id, H5P_CLS_LACC, loc_id, FALSE) < 0)
+    if (H5CX_set_apl(&lapl_id, H5P_CLS_LACC, loc_id, FALSE) < 0)
         HGOTO_ERROR(H5E_OHDR, H5E_CANTSET, FAIL, "can't set access property list info")
 
-    loc_params.type = H5VL_OBJECT_BY_IDX;
-    loc_params.loc_data.loc_by_idx.name = group_name;
+    /* Set location struct fields */
+    loc_params.type                         = H5VL_OBJECT_BY_IDX;
+    loc_params.loc_data.loc_by_idx.name     = group_name;
     loc_params.loc_data.loc_by_idx.idx_type = idx_type;
-    loc_params.loc_data.loc_by_idx.order = order;
-    loc_params.loc_data.loc_by_idx.n = n;
-    loc_params.loc_data.loc_by_idx.lapl_id = lapl_id;
-    loc_params.obj_type = H5I_get_type(loc_id);
+    loc_params.loc_data.loc_by_idx.order    = order;
+    loc_params.loc_data.loc_by_idx.n        = n;
+    loc_params.loc_data.loc_by_idx.lapl_id  = lapl_id;
+    loc_params.obj_type                     = H5I_get_type(loc_id);
 
     /* Get the location object */
-    if(NULL == (vol_obj = H5VL_vol_object(loc_id)))
+    if (NULL == (vol_obj = H5VL_vol_object(loc_id)))
         HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "invalid location identifier")
 
+    /* Set up VOL callback arguments */
+    obj_opt_args.get_native_info.fields = fields;
+    obj_opt_args.get_native_info.ninfo  = oinfo;
+    vol_cb_args.op_type                 = H5VL_NATIVE_OBJECT_GET_NATIVE_INFO;
+    vol_cb_args.args                    = &obj_opt_args;
+
     /* Retrieve the object's information */
-    if(H5VL_object_optional(vol_obj, H5P_DATASET_XFER_DEFAULT, H5_REQUEST_NULL, H5VL_NATIVE_OBJECT_GET_INFO, &loc_params, oinfo, fields) < 0)
-        HGOTO_ERROR(H5E_OHDR, H5E_CANTGET, FAIL, "can't get info for object")
+    if (H5VL_object_optional(vol_obj, &loc_params, &vol_cb_args, H5P_DATASET_XFER_DEFAULT, H5_REQUEST_NULL) <
+        0)
+        HGOTO_ERROR(H5E_OHDR, H5E_CANTGET, FAIL, "can't get native file format info for object")
 
 done:
     FUNC_LEAVE_API(ret_value)
-} /* end H5Oget_info_by_idx2() */
+} /* end H5Oget_native_info_by_idx() */
 
-
 /*-------------------------------------------------------------------------
  * Function:    H5Oset_comment
  *
@@ -717,34 +1534,41 @@ done:
 herr_t
 H5Oset_comment(hid_t obj_id, const char *comment)
 {
-    H5VL_object_t *vol_obj;             /* Object token of loc_id */
-    H5VL_loc_params_t loc_params;
-    herr_t      ret_value = SUCCEED;    /* Return value */
+    H5VL_object_t *                    vol_obj;      /* Object of loc_id */
+    H5VL_optional_args_t               vol_cb_args;  /* Arguments to VOL callback */
+    H5VL_native_object_optional_args_t obj_opt_args; /* Arguments for optional operation */
+    H5VL_loc_params_t                  loc_params;
+    herr_t                             ret_value = SUCCEED; /* Return value */
 
     FUNC_ENTER_API(FAIL)
     H5TRACE2("e", "i*s", obj_id, comment);
 
     /* Get the location object */
-    if(NULL == (vol_obj = H5VL_vol_object(obj_id)))
+    if (NULL == (vol_obj = H5VL_vol_object(obj_id)))
         HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "invalid location identifier")
 
     /* Set up collective metadata if appropriate */
-    if(H5CX_set_loc(obj_id) < 0)
+    if (H5CX_set_loc(obj_id) < 0)
         HGOTO_ERROR(H5E_OHDR, H5E_CANTSET, FAIL, "can't set collective metadata read info")
 
     /* Fill in location struct fields */
-    loc_params.type = H5VL_OBJECT_BY_SELF;
+    loc_params.type     = H5VL_OBJECT_BY_SELF;
     loc_params.obj_type = H5I_get_type(obj_id);
 
+    /* Set up VOL callback arguments */
+    obj_opt_args.set_comment.comment = comment;
+    vol_cb_args.op_type              = H5VL_NATIVE_OBJECT_SET_COMMENT;
+    vol_cb_args.args                 = &obj_opt_args;
+
     /* (Re)set the object's comment */
-    if(H5VL_object_optional(vol_obj, H5P_DATASET_XFER_DEFAULT, H5_REQUEST_NULL, H5VL_NATIVE_OBJECT_SET_COMMENT, &loc_params, comment) < 0)
+    if (H5VL_object_optional(vol_obj, &loc_params, &vol_cb_args, H5P_DATASET_XFER_DEFAULT, H5_REQUEST_NULL) <
+        0)
         HGOTO_ERROR(H5E_OHDR, H5E_CANTSET, FAIL, "can't set comment for object")
 
 done:
     FUNC_LEAVE_API(ret_value)
 } /* end H5Oset_comment() */
 
-
 /*-------------------------------------------------------------------------
  * Function:    H5Oset_comment_by_name
  *
@@ -763,22 +1587,23 @@ done:
  *-------------------------------------------------------------------------
  */
 herr_t
-H5Oset_comment_by_name(hid_t loc_id, const char *name, const char *comment,
-    hid_t lapl_id)
+H5Oset_comment_by_name(hid_t loc_id, const char *name, const char *comment, hid_t lapl_id)
 {
-    H5VL_object_t *vol_obj;             /* Object token of loc_id */
-    H5VL_loc_params_t loc_params;
-    herr_t      ret_value = SUCCEED;    /* Return value */
+    H5VL_object_t *                    vol_obj;      /* Object of loc_id */
+    H5VL_optional_args_t               vol_cb_args;  /* Arguments to VOL callback */
+    H5VL_native_object_optional_args_t obj_opt_args; /* Arguments for optional operation */
+    H5VL_loc_params_t                  loc_params;
+    herr_t                             ret_value = SUCCEED; /* Return value */
 
     FUNC_ENTER_API(FAIL)
     H5TRACE4("e", "i*s*si", loc_id, name, comment, lapl_id);
 
     /* Check args */
-    if(!name || !*name)
+    if (!name || !*name)
         HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "no name")
 
     /* Verify access property list and set up collective metadata if appropriate */
-    if(H5CX_set_apl(&lapl_id, H5P_CLS_LACC, loc_id, TRUE) < 0)
+    if (H5CX_set_apl(&lapl_id, H5P_CLS_LACC, loc_id, TRUE) < 0)
         HGOTO_ERROR(H5E_OHDR, H5E_CANTSET, FAIL, "can't set access property list info")
 
     /* Fill in location struct fields */
@@ -788,18 +1613,23 @@ H5Oset_comment_by_name(hid_t loc_id, const char *name, const char *comment,
     loc_params.obj_type                     = H5I_get_type(loc_id);
 
     /* Get the location object */
-    if(NULL == (vol_obj = H5VL_vol_object(loc_id)))
+    if (NULL == (vol_obj = H5VL_vol_object(loc_id)))
         HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "invalid location identifier")
 
+    /* Set up VOL callback arguments */
+    obj_opt_args.set_comment.comment = comment;
+    vol_cb_args.op_type              = H5VL_NATIVE_OBJECT_SET_COMMENT;
+    vol_cb_args.args                 = &obj_opt_args;
+
     /* (Re)set the object's comment */
-    if(H5VL_object_optional(vol_obj, H5P_DATASET_XFER_DEFAULT, H5_REQUEST_NULL, H5VL_NATIVE_OBJECT_SET_COMMENT, &loc_params, comment) < 0)
+    if (H5VL_object_optional(vol_obj, &loc_params, &vol_cb_args, H5P_DATASET_XFER_DEFAULT, H5_REQUEST_NULL) <
+        0)
         HGOTO_ERROR(H5E_OHDR, H5E_CANTSET, FAIL, "can't set comment for object: '%s'", name)
 
 done:
     FUNC_LEAVE_API(ret_value)
 } /* end H5Oset_comment_by_name() */
 
-
 /*-------------------------------------------------------------------------
  * Function:    H5Oget_comment
  *
@@ -817,32 +1647,45 @@ done:
  *-------------------------------------------------------------------------
  */
 ssize_t
-H5Oget_comment(hid_t obj_id, char *comment, size_t bufsize)
+H5Oget_comment(hid_t obj_id, char *comment /*out*/, size_t bufsize)
 {
-    H5VL_object_t *vol_obj;             /* Object token of loc_id */
-    H5VL_loc_params_t loc_params;
-    ssize_t     ret_value = -1;              /* Return value */
+    H5VL_object_t *                    vol_obj;      /* Object of loc_id */
+    H5VL_optional_args_t               vol_cb_args;  /* Arguments to VOL callback */
+    H5VL_native_object_optional_args_t obj_opt_args; /* Arguments for optional operation */
+    H5VL_loc_params_t                  loc_params;
+    size_t                             comment_len = 0;  /* Length of comment string */
+    ssize_t                            ret_value   = -1; /* Return value */
 
     FUNC_ENTER_API((-1))
-    H5TRACE3("Zs", "i*sz", obj_id, comment, bufsize);
+    H5TRACE3("Zs", "ixz", obj_id, comment, bufsize);
 
     /* Get the object */
-    if(NULL == (vol_obj = H5VL_vol_object(obj_id)))
+    if (NULL == (vol_obj = H5VL_vol_object(obj_id)))
         HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, (-1), "invalid location identifier")
 
     /* Set fields in the location struct */
-    loc_params.type         = H5VL_OBJECT_BY_SELF;
-    loc_params.obj_type     = H5I_get_type(obj_id);
+    loc_params.type     = H5VL_OBJECT_BY_SELF;
+    loc_params.obj_type = H5I_get_type(obj_id);
+
+    /* Set up VOL callback arguments */
+    obj_opt_args.get_comment.buf         = comment;
+    obj_opt_args.get_comment.buf_size    = bufsize;
+    obj_opt_args.get_comment.comment_len = &comment_len;
+    vol_cb_args.op_type                  = H5VL_NATIVE_OBJECT_GET_COMMENT;
+    vol_cb_args.args                     = &obj_opt_args;
 
     /* Retrieve the object's comment */
-    if(H5VL_object_optional(vol_obj, H5P_DATASET_XFER_DEFAULT, H5_REQUEST_NULL, H5VL_NATIVE_OBJECT_GET_COMMENT, &loc_params, comment, bufsize, &ret_value) < 0)
+    if (H5VL_object_optional(vol_obj, &loc_params, &vol_cb_args, H5P_DATASET_XFER_DEFAULT, H5_REQUEST_NULL) <
+        0)
         HGOTO_ERROR(H5E_OHDR, H5E_CANTGET, (-1), "can't get comment for object")
 
+    /* Set return value */
+    ret_value = (ssize_t)comment_len;
+
 done:
     FUNC_LEAVE_API(ret_value)
 } /* end H5Oget_comment() */
 
-
 /*-------------------------------------------------------------------------
  * Function:    H5Oget_comment_by_name
  *
@@ -860,22 +1703,24 @@ done:
  *-------------------------------------------------------------------------
  */
 ssize_t
-H5Oget_comment_by_name(hid_t loc_id, const char *name, char *comment, size_t bufsize,
-    hid_t lapl_id)
+H5Oget_comment_by_name(hid_t loc_id, const char *name, char *comment /*out*/, size_t bufsize, hid_t lapl_id)
 {
-    H5VL_object_t *vol_obj;             /* Object token of loc_id */
-    H5VL_loc_params_t loc_params;
-    ssize_t     ret_value = -1;              /* Return value */
+    H5VL_object_t *                    vol_obj;      /* Object of loc_id */
+    H5VL_optional_args_t               vol_cb_args;  /* Arguments to VOL callback */
+    H5VL_native_object_optional_args_t obj_opt_args; /* Arguments for optional operation */
+    H5VL_loc_params_t                  loc_params;
+    size_t                             comment_len = 0;  /* Length of comment string */
+    ssize_t                            ret_value   = -1; /* Return value */
 
     FUNC_ENTER_API((-1))
-    H5TRACE5("Zs", "i*s*szi", loc_id, name, comment, bufsize, lapl_id);
+    H5TRACE5("Zs", "i*sxzi", loc_id, name, comment, bufsize, lapl_id);
 
     /* Check args */
-    if(!name || !*name)
+    if (!name || !*name)
         HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, (-1), "no name")
 
     /* Verify access property list and set up collective metadata if appropriate */
-    if(H5CX_set_apl(&lapl_id, H5P_CLS_LACC, loc_id, FALSE) < 0)
+    if (H5CX_set_apl(&lapl_id, H5P_CLS_LACC, loc_id, FALSE) < 0)
         HGOTO_ERROR(H5E_OHDR, H5E_CANTSET, (-1), "can't set access property list info")
 
     /* Fill in location struct fields */
@@ -885,20 +1730,30 @@ H5Oget_comment_by_name(hid_t loc_id, const char *name, char *comment, size_t buf
     loc_params.obj_type                     = H5I_get_type(loc_id);
 
     /* Get the location object */
-    if(NULL == (vol_obj = H5VL_vol_object(loc_id)))
+    if (NULL == (vol_obj = H5VL_vol_object(loc_id)))
         HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, (-1), "invalid location identifier")
 
+    /* Set up VOL callback arguments */
+    obj_opt_args.get_comment.buf         = comment;
+    obj_opt_args.get_comment.buf_size    = bufsize;
+    obj_opt_args.get_comment.comment_len = &comment_len;
+    vol_cb_args.op_type                  = H5VL_NATIVE_OBJECT_GET_COMMENT;
+    vol_cb_args.args                     = &obj_opt_args;
+
     /* Retrieve the object's comment */
-    if(H5VL_object_optional(vol_obj, H5P_DATASET_XFER_DEFAULT, H5_REQUEST_NULL, H5VL_NATIVE_OBJECT_GET_COMMENT, &loc_params, comment, bufsize, &ret_value) < 0)
+    if (H5VL_object_optional(vol_obj, &loc_params, &vol_cb_args, H5P_DATASET_XFER_DEFAULT, H5_REQUEST_NULL) <
+        0)
         HGOTO_ERROR(H5E_OHDR, H5E_CANTGET, (-1), "can't get comment for object: '%s'", name)
 
+    /* Set return value */
+    ret_value = (ssize_t)comment_len;
+
 done:
     FUNC_LEAVE_API(ret_value)
 } /* end H5Oget_comment_by_name() */
 
-
 /*-------------------------------------------------------------------------
- * Function:    H5Ovisit2
+ * Function:    H5Ovisit3
  *
  * Purpose:     Recursively visit an object and all the objects reachable
  *              from it.  If the starting object is a group, all the objects
@@ -933,45 +1788,54 @@ done:
  *-------------------------------------------------------------------------
  */
 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)
+H5Ovisit3(hid_t obj_id, H5_index_t idx_type, H5_iter_order_t order, H5O_iterate2_t op, void *op_data,
+          unsigned fields)
 {
-    H5VL_object_t *vol_obj;             /* Object token of loc_id */
-    H5VL_loc_params_t   loc_params;
-    herr_t              ret_value;              /* Return value */
+    H5VL_object_t *             vol_obj;     /* Object of loc_id */
+    H5VL_object_specific_args_t vol_cb_args; /* Arguments to VOL callback */
+    H5VL_loc_params_t           loc_params;  /* Location parameters for object access */
+    herr_t                      ret_value;   /* Return value */
 
     FUNC_ENTER_API(FAIL)
-    H5TRACE6("e", "iIiIox*xIu", obj_id, idx_type, order, op, op_data, fields);
+    H5TRACE6("e", "iIiIoOI*xIu", obj_id, idx_type, order, op, op_data, fields);
 
     /* Check args */
-    if(idx_type <= H5_INDEX_UNKNOWN || idx_type >= H5_INDEX_N)
+    if (idx_type <= H5_INDEX_UNKNOWN || idx_type >= H5_INDEX_N)
         HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "invalid index type specified")
-    if(order <= H5_ITER_UNKNOWN || order >= H5_ITER_N)
+    if (order <= H5_ITER_UNKNOWN || order >= H5_ITER_N)
         HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "invalid iteration order specified")
-    if(!op)
+    if (!op)
         HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "no callback operator specified")
-    if(fields & ~H5O_INFO_ALL)
+    if (fields & ~H5O_INFO_ALL)
         HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "invalid fields")
 
     /* Get the location object */
-    if(NULL == (vol_obj = H5VL_vol_object(obj_id)))
+    if (NULL == (vol_obj = H5VL_vol_object(obj_id)))
         HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "invalid location identifier")
 
     /* Set location parameters */
-    loc_params.type         = H5VL_OBJECT_BY_SELF;
-    loc_params.obj_type     = H5I_get_type(obj_id);
+    loc_params.type     = H5VL_OBJECT_BY_SELF;
+    loc_params.obj_type = H5I_get_type(obj_id);
+
+    /* Set up VOL callback arguments */
+    vol_cb_args.op_type             = H5VL_OBJECT_VISIT;
+    vol_cb_args.args.visit.idx_type = idx_type;
+    vol_cb_args.args.visit.order    = order;
+    vol_cb_args.args.visit.op       = op;
+    vol_cb_args.args.visit.op_data  = op_data;
+    vol_cb_args.args.visit.fields   = fields;
 
     /* Visit the objects */
-    if((ret_value = H5VL_object_specific(vol_obj, &loc_params, H5VL_OBJECT_VISIT, H5P_DATASET_XFER_DEFAULT, H5_REQUEST_NULL, (int)idx_type, (int)order, op, op_data, fields)) < 0)
+    if ((ret_value = H5VL_object_specific(vol_obj, &loc_params, &vol_cb_args, H5P_DATASET_XFER_DEFAULT,
+                                          H5_REQUEST_NULL)) < 0)
         HGOTO_ERROR(H5E_OHDR, H5E_BADITER, FAIL, "object iteration failed")
 
 done:
     FUNC_LEAVE_API(ret_value)
-} /* end H5Ovisit2() */
+} /* end H5Ovisit3() */
 
-
 /*-------------------------------------------------------------------------
- * Function:    H5Ovisit_by_name2
+ * Function:    H5Ovisit_by_name3
  *
  * Purpose:     Recursively visit an object and all the objects reachable
  *              from it.  If the starting object is a group, all the objects
@@ -1006,37 +1870,37 @@ done:
  *-------------------------------------------------------------------------
  */
 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)
+H5Ovisit_by_name3(hid_t loc_id, const char *obj_name, H5_index_t idx_type, H5_iter_order_t order,
+                  H5O_iterate2_t op, void *op_data, unsigned fields, hid_t lapl_id)
 {
-    H5VL_object_t *vol_obj;             /* Object token of loc_id */
-    H5VL_loc_params_t   loc_params; 
-    herr_t              ret_value;              /* Return value */
+    H5VL_object_t *             vol_obj;     /* Object of loc_id */
+    H5VL_object_specific_args_t vol_cb_args; /* Arguments to VOL callback */
+    H5VL_loc_params_t           loc_params;  /* Location parameters for object access */
+    herr_t                      ret_value;   /* Return value */
 
     FUNC_ENTER_API(FAIL)
-    H5TRACE8("e", "i*sIiIox*xIui", loc_id, obj_name, idx_type, order, op, op_data,
-             fields, lapl_id);
+    H5TRACE8("e", "i*sIiIoOI*xIui", loc_id, obj_name, idx_type, order, op, op_data, fields, lapl_id);
 
     /* Check args */
-    if(!obj_name)
+    if (!obj_name)
         HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "obj_name parameter cannot be NULL")
-    if(!*obj_name)
+    if (!*obj_name)
         HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "obj_name parameter cannot be an empty string")
-    if(idx_type <= H5_INDEX_UNKNOWN || idx_type >= H5_INDEX_N)
+    if (idx_type <= H5_INDEX_UNKNOWN || idx_type >= H5_INDEX_N)
         HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "invalid index type specified")
-    if(order <= H5_ITER_UNKNOWN || order >= H5_ITER_N)
+    if (order <= H5_ITER_UNKNOWN || order >= H5_ITER_N)
         HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "invalid iteration order specified")
-    if(!op)
+    if (!op)
         HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "no callback operator specified")
-    if(fields & ~H5O_INFO_ALL)
+    if (fields & ~H5O_INFO_ALL)
         HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "invalid fields")
 
     /* Verify access property list and set up collective metadata if appropriate */
-    if(H5CX_set_apl(&lapl_id, H5P_CLS_LACC, loc_id, FALSE) < 0)
+    if (H5CX_set_apl(&lapl_id, H5P_CLS_LACC, loc_id, FALSE) < 0)
         HGOTO_ERROR(H5E_OHDR, H5E_CANTSET, FAIL, "can't set access property list info")
 
     /* Get the location object */
-    if(NULL == (vol_obj = H5VL_vol_object(loc_id)))
+    if (NULL == (vol_obj = H5VL_vol_object(loc_id)))
         HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "invalid location identifier")
 
     /* Set location parameters */
@@ -1045,50 +1909,48 @@ H5Ovisit_by_name2(hid_t loc_id, const char *obj_name, H5_index_t idx_type,
     loc_params.loc_data.loc_by_name.lapl_id = lapl_id;
     loc_params.obj_type                     = H5I_get_type(loc_id);
 
+    /* Set up VOL callback arguments */
+    vol_cb_args.op_type             = H5VL_OBJECT_VISIT;
+    vol_cb_args.args.visit.idx_type = idx_type;
+    vol_cb_args.args.visit.order    = order;
+    vol_cb_args.args.visit.op       = op;
+    vol_cb_args.args.visit.op_data  = op_data;
+    vol_cb_args.args.visit.fields   = fields;
+
     /* Visit the objects */
-    if((ret_value = H5VL_object_specific(vol_obj, &loc_params, H5VL_OBJECT_VISIT, H5P_DATASET_XFER_DEFAULT, H5_REQUEST_NULL, (int)idx_type, (int)order, op, op_data, fields)) < 0)
+    if ((ret_value = H5VL_object_specific(vol_obj, &loc_params, &vol_cb_args, H5P_DATASET_XFER_DEFAULT,
+                                          H5_REQUEST_NULL)) < 0)
         HGOTO_ERROR(H5E_OHDR, H5E_BADITER, FAIL, "object iteration failed")
 
 done:
     FUNC_LEAVE_API(ret_value)
-} /* end H5Ovisit_by_name2() */
+} /* end H5Ovisit_by_name3() */
 
-
 /*-------------------------------------------------------------------------
- * Function:    H5Oclose
- *
- * Purpose:     Close an open file object.
- *
- *              This is the companion to H5Oopen. It is used to close any
- *              open object in an HDF5 file (but not IDs are that not file
- *              objects, such as property lists and dataspaces). It has
- *              the same effect as calling H5Gclose, H5Dclose, or H5Tclose.
+ * Function:    H5O__close_check_type
  *
- * Return:      SUCCEED/FAIL
+ * Purpose:     This is the common function to validate an object
+ *              before closing it.
  *
- * Programmer:	James Laird
- *		July 14 2006
+ * Return:      TRUE/FALSE/FAIL
  *
  *-------------------------------------------------------------------------
  */
-herr_t
-H5Oclose(hid_t object_id)
+static htri_t
+H5O__close_check_type(hid_t object_id)
 {
-    herr_t       ret_value = SUCCEED;
+    htri_t ret_value = TRUE; /* Return value */
 
-    FUNC_ENTER_API(FAIL)
-    H5TRACE1("e", "i", object_id);
+    FUNC_ENTER_PACKAGE
 
-    /* Get the type of the object and close it in the correct way */
-    switch(H5I_get_type(object_id)) {
+    /* Check for closeable object */
+    switch (H5I_get_type(object_id)) {
         case H5I_GROUP:
         case H5I_DATATYPE:
         case H5I_DATASET:
         case H5I_MAP:
-            if(H5I_object(object_id) == NULL)
+            if (H5I_object(object_id) == NULL)
                 HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "not a valid object")
-            if(H5I_dec_app_ref(object_id) < 0)
-                HGOTO_ERROR(H5E_OHDR, H5E_CANTRELEASE, FAIL, "unable to close object")
             break;
 
         case H5I_UNINIT:
@@ -1104,127 +1966,458 @@ H5Oclose(hid_t object_id)
         case H5I_ERROR_MSG:
         case H5I_ERROR_STACK:
         case H5I_SPACE_SEL_ITER:
+        case H5I_EVENTSET:
         case H5I_NTYPES:
         default:
-            HGOTO_ERROR(H5E_ARGS, H5E_CANTRELEASE, FAIL, "not a valid file object ID (dataset, group, or datatype)")
-        break;
+            HGOTO_DONE(FALSE);
+            break;
     } /* end switch */
 
 done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* H5O__close_check_type() */
+
+/*-------------------------------------------------------------------------
+ * Function:    H5Oclose
+ *
+ * Purpose:     Close an open file object.
+ *
+ *              This is the companion to H5Oopen. It is used to close any
+ *              open object in an HDF5 file (but not IDs are that not file
+ *              objects, such as property lists and dataspaces). It has
+ *              the same effect as calling H5Gclose, H5Dclose, or H5Tclose.
+ *
+ * Return:      SUCCEED/FAIL
+ *
+ * Programmer:  James Laird
+ *              July 14 2006
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5Oclose(hid_t object_id)
+{
+    herr_t ret_value = SUCCEED;
+
+    FUNC_ENTER_API(FAIL)
+    H5TRACE1("e", "i", object_id);
+
+    /* Validate the object type before closing */
+    if (H5O__close_check_type(object_id) <= 0)
+        HGOTO_ERROR(H5E_OHDR, H5E_CANTRELEASE, FAIL, "not a valid object")
+
+    if (H5I_dec_app_ref(object_id) < 0)
+        HGOTO_ERROR(H5E_OHDR, H5E_CANTRELEASE, FAIL, "unable to close object")
+
+done:
     FUNC_LEAVE_API(ret_value)
 } /* end H5Oclose() */
 
-
 /*-------------------------------------------------------------------------
- * Function:	H5Odisable_mdc_flushes
+ * Function:    H5Oclose_async
  *
- * Purpose:	To "cork" an object:
- *		--keep dirty entries associated with the object in the metadata cache
+ * Purpose:     Asynchronous version of H5Oclose
  *
- * Return:	Success:	Non-negative
- *		Failure:	Negative
+ * Return:      SUCCEED/FAIL
  *
- * Programmer:	Vailin Choi
- *		January 2014
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5Oclose_async(const char *app_file, const char *app_func, unsigned app_line, hid_t object_id, hid_t es_id)
+{
+    H5VL_object_t *vol_obj   = NULL;            /* Object for loc_id */
+    H5VL_t *       connector = NULL;            /* VOL connector */
+    void *         token     = NULL;            /* Request token for async operation        */
+    void **        token_ptr = H5_REQUEST_NULL; /* Pointer to request token for async operation        */
+    herr_t         ret_value = SUCCEED;
+
+    FUNC_ENTER_API(FAIL)
+    H5TRACE5("e", "*s*sIuii", app_file, app_func, app_line, object_id, es_id);
+
+    /* Validate the object type before closing */
+    if (H5O__close_check_type(object_id) <= 0)
+        HGOTO_ERROR(H5E_OHDR, H5E_CANTRELEASE, FAIL, "not a valid object")
+
+    /* Prepare for possible asynchronous operation */
+    if (H5ES_NONE != es_id) {
+        /* Get file object's connector */
+        if (NULL == (vol_obj = H5VL_vol_object(object_id)))
+            HGOTO_ERROR(H5E_OHDR, H5E_CANTGET, FAIL, "can't get VOL object for object")
+
+        /* Increase connector's refcount, so it doesn't get closed if closing
+         * this object ID closes the file */
+        connector = vol_obj->connector;
+        H5VL_conn_inc_rc(connector);
+
+        /* Point at token for operation to set up */
+        token_ptr = &token;
+    } /* end if */
+
+    /* Asynchronously decrement reference count on ID.
+     * When it reaches zero the object will be closed.
+     */
+    if (H5I_dec_app_ref_async(object_id, token_ptr) < 0)
+        HGOTO_ERROR(H5E_OHDR, H5E_CANTCLOSEFILE, FAIL, "decrementing object ID failed")
+
+    /* If a token was created, add the token to the event set */
+    if (NULL != token)
+        /* clang-format off */
+        if (H5ES_insert(es_id, vol_obj->connector, token,
+                        H5ARG_TRACE5(__func__, "*s*sIuii", app_file, app_func, app_line, object_id, es_id)) < 0)
+            /* clang-format on */
+            HGOTO_ERROR(H5E_OHDR, H5E_CANTINSERT, FAIL, "can't insert token into event set")
+
+done:
+    if (connector && H5VL_conn_dec_rc(connector) < 0)
+        HDONE_ERROR(H5E_OHDR, H5E_CANTDEC, FAIL, "can't decrement ref count on connector")
+
+    FUNC_LEAVE_API(ret_value)
+} /* end H5Oclose_async() */
+
+/*-------------------------------------------------------------------------
+ * Function:    H5O__disable_mdc_flushes
+ *
+ * Purpose:     Private version of the metadata cache cork function.
+ *
+ * Return:      SUCCEED/FAIL
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5O__disable_mdc_flushes(H5O_loc_t *oloc)
+{
+    herr_t ret_value = SUCCEED;
+
+    FUNC_ENTER_PACKAGE
+
+    if (H5AC_cork(oloc->file, oloc->addr, H5AC__SET_CORK, NULL) < 0)
+        HGOTO_ERROR(H5E_OHDR, H5E_CANTCORK, FAIL, "unable to cork object");
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value);
+} /* H5O__disable_mdc_flushes() */
+
+/*-------------------------------------------------------------------------
+ * Function:    H5Odisable_mdc_flushes
+ *
+ * Purpose:     "Cork" an object, keeping dirty entries associated with the
+ *              object in the metadata cache.
+ *
+ * Return:      Success:    Non-negative
+ *              Failure:    Negative
+ *
+ * Programmer:  Vailin Choi
+ *              January 2014
  *
  *-------------------------------------------------------------------------
  */
 herr_t
 H5Odisable_mdc_flushes(hid_t object_id)
 {
-    H5O_loc_t  *oloc;			/* Object location */
-    herr_t      ret_value = SUCCEED;	/* Return value */
+    H5VL_object_t *      vol_obj;             /* Object of loc_id */
+    H5VL_optional_args_t vol_cb_args;         /* Arguments to VOL callback */
+    H5VL_loc_params_t    loc_params;          /* Location parameters */
+    herr_t               ret_value = SUCCEED; /* Return value */
 
-    FUNC_ENTER_API(FAIL)
+    FUNC_ENTER_API(FAIL);
     H5TRACE1("e", "i", object_id);
 
-    /* Get the object's oloc */
-    if(NULL == (oloc = H5O_get_loc(object_id)))
-        HGOTO_ERROR(H5E_OHDR, H5E_BADVALUE, FAIL, "unable to get object location from ID")
+    /* Make sure the ID is a file object */
+    if (H5I_is_file_object(object_id) != TRUE)
+        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "ID is not a file object");
 
-    if(H5AC_cork(oloc->file, oloc->addr, H5AC__SET_CORK, NULL) < 0)
-        HGOTO_ERROR(H5E_OHDR, H5E_CANTCORK, FAIL, "unable to cork an object")
+    /* Get the VOL object */
+    if (NULL == (vol_obj = H5VL_vol_object(object_id)))
+        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "invalid object ID");
+
+    /* Fill in location struct fields */
+    loc_params.type     = H5VL_OBJECT_BY_SELF;
+    loc_params.obj_type = H5I_get_type(object_id);
+
+    /* Set up VOL callback arguments */
+    vol_cb_args.op_type = H5VL_NATIVE_OBJECT_DISABLE_MDC_FLUSHES;
+    vol_cb_args.args    = NULL;
+
+    /* Cork the object */
+    if (H5VL_object_optional(vol_obj, &loc_params, &vol_cb_args, H5P_DATASET_XFER_DEFAULT, H5_REQUEST_NULL) <
+        0)
+        HGOTO_ERROR(H5E_OHDR, H5E_CANTCORK, FAIL, "unable to cork object");
 
 done:
-    FUNC_LEAVE_API(ret_value)
+    FUNC_LEAVE_API(ret_value);
 } /* H5Odisable_mdc_flushes() */
 
-
 /*-------------------------------------------------------------------------
- * Function:	H5Oenable_mdc_flushes
+ * Function:    H5O__enable_mdc_flushes
  *
- * Purpose:	To "uncork" an object
- *		--release keeping dirty entries associated with the object 
- *		  in the metadata cache
+ * Purpose:     Private version of the metadata cache uncork function.
  *
- * Return:	Success:	Non-negative
- *		Failure:	Negative
+ * Return:      SUCCEED/FAIL
  *
- * Programmer:	Vailin Choi
- *		January 2014
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5O__enable_mdc_flushes(H5O_loc_t *oloc)
+{
+    herr_t ret_value = SUCCEED;
+
+    FUNC_ENTER_PACKAGE
+
+    if (H5AC_cork(oloc->file, oloc->addr, H5AC__UNCORK, NULL) < 0)
+        HGOTO_ERROR(H5E_OHDR, H5E_CANTUNCORK, FAIL, "unable to uncork object");
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value);
+} /* H5O__enable_mdc_flushes() */
+
+/*-------------------------------------------------------------------------
+ * Function:    H5Oenable_mdc_flushes
+ *
+ * Purpose:     "Uncork" an object, allowing dirty entries associated with
+ *              the object to be flushed.
+ *
+ * Return:      Success:    Non-negative
+ *              Failure:    Negative
+ *
+ * Programmer:  Vailin Choi
+ *              January 2014
  *
  *-------------------------------------------------------------------------
  */
 herr_t
 H5Oenable_mdc_flushes(hid_t object_id)
 {
-    H5O_loc_t  *oloc;			/* Object location */
-    herr_t      ret_value = SUCCEED;	/* Return value */
+    H5VL_object_t *      vol_obj;             /* Object of loc_id */
+    H5VL_optional_args_t vol_cb_args;         /* Arguments to VOL callback */
+    H5VL_loc_params_t    loc_params;          /* Location parameters */
+    herr_t               ret_value = SUCCEED; /* Return value */
 
-    FUNC_ENTER_API(FAIL)
+    FUNC_ENTER_API(FAIL);
     H5TRACE1("e", "i", object_id);
 
-    /* Get the object's oloc */
-    if(NULL == (oloc = H5O_get_loc(object_id)))
-        HGOTO_ERROR(H5E_OHDR, H5E_BADVALUE, FAIL, "unable to get object location from ID")
+    /* Make sure the ID is a file object */
+    if (H5I_is_file_object(object_id) != TRUE)
+        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "ID is not a file object");
+
+    /* Get the VOL object */
+    if (NULL == (vol_obj = H5VL_vol_object(object_id)))
+        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "invalid object ID");
+
+    /* Fill in location struct fields */
+    loc_params.type     = H5VL_OBJECT_BY_SELF;
+    loc_params.obj_type = H5I_get_type(object_id);
+
+    /* Set up VOL callback arguments */
+    vol_cb_args.op_type = H5VL_NATIVE_OBJECT_ENABLE_MDC_FLUSHES;
+    vol_cb_args.args    = NULL;
 
-    /* Set the value */
-    if(H5AC_cork(oloc->file, oloc->addr, H5AC__UNCORK, NULL) < 0)
-        HGOTO_ERROR(H5E_OHDR, H5E_CANTUNCORK, FAIL, "unable to uncork an object")
+    /* Uncork the object */
+    if (H5VL_object_optional(vol_obj, &loc_params, &vol_cb_args, H5P_DATASET_XFER_DEFAULT, H5_REQUEST_NULL) <
+        0)
+        HGOTO_ERROR(H5E_OHDR, H5E_CANTUNCORK, FAIL, "unable to uncork object");
 
 done:
-    FUNC_LEAVE_API(ret_value)
+    FUNC_LEAVE_API(ret_value);
 } /* H5Oenable_mdc_flushes() */
 
-
 /*-------------------------------------------------------------------------
- * Function:	H5Oare_mdc_flushes_disabled
+ * Function:    H5O__are_mdc_flushes_disabled
  *
- * Purpose:	Retrieve the object's "cork" status in the parameter "are_disabled":
- *		  TRUE if mdc flushes for the object is disabled
- *		  FALSE if mdc flushes for the object is not disabled
- *		Return error if the parameter "are_disabled" is not supplied
+ * Purpose:     Private version of cork status getter.
  *
- * Return:	Success:	Non-negative
- *		Failure:	Negative
+ * Return:      SUCCEED/FAIL
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5O__are_mdc_flushes_disabled(const H5O_loc_t *oloc, hbool_t *are_disabled)
+{
+    herr_t ret_value = SUCCEED;
+
+    FUNC_ENTER_PACKAGE
+
+    HDassert(are_disabled);
+
+    if (H5AC_cork(oloc->file, oloc->addr, H5AC__GET_CORKED, are_disabled) < 0)
+        HGOTO_ERROR(H5E_OHDR, H5E_CANTGET, FAIL, "unable to retrieve object's cork status");
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* H5O__are_mdc_flushes_disabled() */
+
+/*-------------------------------------------------------------------------
+ * Function:    H5Oare_mdc_flushes_disabled
+ *
+ * Purpose:     Retrieve the object's "cork" status in the parameter "are_disabled":
+ *                  TRUE if mdc flushes for the object is disabled
+ *                  FALSE if mdc flushes for the object is not disabled
+ *
+ *              Return error if the parameter "are_disabled" is not supplied
+ *
+ * Return:      Success:    Non-negative
+ *              Failure:    Negative
  *
- * Programmer:	Vailin Choi
- *		January 2014
+ * Programmer:  Vailin Choi
+ *              January 2014
  *
  *-------------------------------------------------------------------------
  */
 herr_t
 H5Oare_mdc_flushes_disabled(hid_t object_id, hbool_t *are_disabled)
 {
-    H5O_loc_t  *oloc;			/* Object location */
-    herr_t      ret_value = SUCCEED;	/* Return value */
+    H5VL_object_t *                    vol_obj;             /* Object of loc_id */
+    H5VL_optional_args_t               vol_cb_args;         /* Arguments to VOL callback */
+    H5VL_native_object_optional_args_t obj_opt_args;        /* Arguments for optional operation */
+    H5VL_loc_params_t                  loc_params;          /* Location parameters */
+    herr_t                             ret_value = SUCCEED; /* Return value */
 
-    FUNC_ENTER_API(FAIL)
+    FUNC_ENTER_API(FAIL);
     H5TRACE2("e", "i*b", object_id, are_disabled);
 
-    /* Check args */
+    /* Sanity check */
+    if (!are_disabled)
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "unable to get object location from ID");
+
+    /* Make sure the ID is a file object */
+    if (H5I_is_file_object(object_id) != TRUE)
+        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "ID is not a file object");
+
+    /* Get the VOL object */
+    if (NULL == (vol_obj = H5VL_vol_object(object_id)))
+        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "invalid object ID");
+
+    /* Fill in location struct fields */
+    loc_params.type     = H5VL_OBJECT_BY_SELF;
+    loc_params.obj_type = H5I_get_type(object_id);
 
-    /* Get the object's oloc */
-    if(NULL == (oloc = H5O_get_loc(object_id)))
-        HGOTO_ERROR(H5E_OHDR, H5E_BADVALUE, FAIL, "unable to get object location from ID")
-    if(!are_disabled)
-        HGOTO_ERROR(H5E_OHDR, H5E_BADVALUE, FAIL, "unable to get object location from ID")
+    /* Set up VOL callback arguments */
+    obj_opt_args.are_mdc_flushes_disabled.flag = are_disabled;
+    vol_cb_args.op_type                        = H5VL_NATIVE_OBJECT_ARE_MDC_FLUSHES_DISABLED;
+    vol_cb_args.args                           = &obj_opt_args;
 
     /* Get the cork status */
-    if(H5AC_cork(oloc->file, oloc->addr, H5AC__GET_CORKED, are_disabled) < 0)
-        HGOTO_ERROR(H5E_OHDR, H5E_CANTGET, FAIL, "unable to retrieve an object's cork status")
+    if (H5VL_object_optional(vol_obj, &loc_params, &vol_cb_args, H5P_DATASET_XFER_DEFAULT, H5_REQUEST_NULL) <
+        0)
+        HGOTO_ERROR(H5E_OHDR, H5E_CANTGET, FAIL, "unable to retrieve object's cork status");
 
 done:
     FUNC_LEAVE_API(ret_value)
 } /* H5Oare_mdc_flushes_disabled() */
 
+/*---------------------------------------------------------------------------
+ * Function:    H5Otoken_cmp
+ *
+ * Purpose:     Compares two VOL connector object tokens
+ *
+ * Note:        Both object tokens must be from the same VOL connector class
+ *
+ * Return:      Success:    Non-negative, with *cmp_value set to positive if
+ *                          token1 is greater than token2, negative if token2
+ *                          is greater than token1 and zero if token1 and
+ *                          token2 are equal.
+ *              Failure:    Negative
+ *
+ *---------------------------------------------------------------------------
+ */
+herr_t
+H5Otoken_cmp(hid_t loc_id, const H5O_token_t *token1, const H5O_token_t *token2, int *cmp_value)
+{
+    H5VL_object_t *vol_obj;             /* VOL object for ID */
+    herr_t         ret_value = SUCCEED; /* Return value */
+
+    FUNC_ENTER_API(FAIL)
+    H5TRACE4("e", "i*k*k*Is", loc_id, token1, token2, cmp_value);
+
+    /* Get the location object */
+    if (NULL == (vol_obj = H5VL_vol_object(loc_id)))
+        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "invalid location identifier")
+    if (NULL == cmp_value)
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "invalid cmp_value pointer")
+
+    /* Compare the two tokens */
+    if (H5VL_token_cmp(vol_obj, token1, token2, cmp_value) < 0)
+        HGOTO_ERROR(H5E_OHDR, H5E_CANTCOMPARE, FAIL, "object token comparison failed")
+
+done:
+    FUNC_LEAVE_API(ret_value)
+} /* end H5Otoken_cmp() */
+
+/*---------------------------------------------------------------------------
+ * Function:    H5Otoken_to_str
+ *
+ * Purpose:     Serialize a connector's object token into a string
+ *
+ * Return:      Success:    Non-negative
+ *              Failure:    Negative
+ *
+ *---------------------------------------------------------------------------
+ */
+herr_t
+H5Otoken_to_str(hid_t loc_id, const H5O_token_t *token, char **token_str)
+{
+    H5VL_object_t *vol_obj;             /* VOL object for ID */
+    H5I_type_t     vol_obj_type;        /* VOL object's type */
+    herr_t         ret_value = SUCCEED; /* Return value */
+
+    FUNC_ENTER_API(FAIL)
+    H5TRACE3("e", "i*k**s", loc_id, token, token_str);
+
+    /* Get the location object */
+    if (NULL == (vol_obj = H5VL_vol_object(loc_id)))
+        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "invalid location identifier")
+    if (NULL == token)
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "invalid token pointer")
+    if (NULL == token_str)
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "invalid token string pointer")
+
+    /* Get object type */
+    if ((vol_obj_type = H5I_get_type(loc_id)) < 0)
+        HGOTO_ERROR(H5E_OHDR, H5E_CANTGET, FAIL, "can't get underlying VOL object type")
+
+    /* Serialize the token */
+    if (H5VL_token_to_str(vol_obj, vol_obj_type, token, token_str) < 0)
+        HGOTO_ERROR(H5E_OHDR, H5E_CANTSERIALIZE, FAIL, "object token serialization failed")
+
+done:
+    FUNC_LEAVE_API(ret_value)
+} /* end H5Otoken_to_str() */
+
+/*---------------------------------------------------------------------------
+ * Function:    H5Otoken_from_str
+ *
+ * Purpose:     Deserialize a string into a connector object token
+ *
+ * Return:      Success:    Non-negative
+ *              Failure:    Negative
+ *
+ *---------------------------------------------------------------------------
+ */
+herr_t
+H5Otoken_from_str(hid_t loc_id, const char *token_str, H5O_token_t *token)
+{
+    H5VL_object_t *vol_obj;             /* VOL object for ID */
+    H5I_type_t     vol_obj_type;        /* VOL object's type */
+    herr_t         ret_value = SUCCEED; /* Return value */
+
+    FUNC_ENTER_API(FAIL)
+    H5TRACE3("e", "i*s*k", loc_id, token_str, token);
+
+    /* Get the location object */
+    if (NULL == (vol_obj = H5VL_vol_object(loc_id)))
+        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "invalid location identifier")
+    if (NULL == token)
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "invalid token pointer")
+    if (NULL == token_str)
+        HGOTO_ERROR(H5E_ARGS, H5E_BADVALUE, FAIL, "invalid token string pointer")
+
+    /* Get object type */
+    if ((vol_obj_type = H5I_get_type(loc_id)) < 0)
+        HGOTO_ERROR(H5E_OHDR, H5E_CANTGET, FAIL, "can't get underlying VOL object type")
+
+    /* Deserialize the token */
+    if (H5VL_token_from_str(vol_obj, vol_obj_type, token_str, token) < 0)
+        HGOTO_ERROR(H5E_OHDR, H5E_CANTUNSERIALIZE, FAIL, "object token deserialization failed")
+
+done:
+    FUNC_LEAVE_API(ret_value)
+} /* end H5Otoken_from_str() */