Refactor, standardize, and revise the async request callbacks.

7 files changed, 441 insertions, 73 deletions

diff --git a/examples/h5_vol_external_log_native.c b/examples/h5_vol_external_log_native.c
index 9c761a5..d84aa9e 100644
--- a/examples/h5_vol_external_log_native.c
+++ b/examples/h5_vol_external_log_native.c
@@ -116,10 +116,12 @@ static const H5VL_class_t H5VL_log_g = {
         H5VL_log_object_specific,                    /* specific */
         NULL, //H5VL_log_object_optional,            /* optional */
     },
-    {
-        NULL,
-        NULL,
-        NULL
+    {                                           /* request_cls */
+        NULL,                                       /* wait         */
+        NULL,                                       /* cancel       */
+        NULL,                                       /* specific     */
+        NULL,                                       /* optional     */
+        NULL                                        /* free         */
     },
     NULL
 };
diff --git a/src/H5ESpublic.h b/src/H5ESpublic.h
index cb8eebf..2df1a6e 100644
--- a/src/H5ESpublic.h
+++ b/src/H5ESpublic.h
@@ -29,7 +29,7 @@ typedef enum H5ES_status_t {
     H5ES_STATUS_IN_PROGRESS,   /* Operation has not yet completed                       */
     H5ES_STATUS_SUCCEED,       /* Operation has completed, successfully                 */
     H5ES_STATUS_FAIL,          /* Operation has completed, but failed                   */
-    H5ES_STATUS_CANCEL         /* Operation has not completed and has been cancelled    */
+    H5ES_STATUS_CANCELLED      /* Operation has not completed and was cancelled         */
 } H5ES_status_t;
 
 
diff --git a/src/H5VLcallback.c b/src/H5VLcallback.c
index a6286c6..76143d6 100644
--- a/src/H5VLcallback.c
+++ b/src/H5VLcallback.c
@@ -163,6 +163,14 @@ static herr_t H5VL__datatype_optional(void *obj, const H5VL_class_t *cls,
     hid_t dxpl_id, void **req, va_list arguments);
 static herr_t H5VL__datatype_close(void *obj, const H5VL_class_t *cls, hid_t dxpl_id,
     void **req);
+static herr_t H5VL__request_wait(void *req, const H5VL_class_t *cls,
+    uint64_t timeout, H5ES_status_t *status);
+static herr_t H5VL__request_cancel(void *req, const H5VL_class_t *cls);
+static herr_t H5VL__request_specific(void *req, const H5VL_class_t *cls,
+    H5VL_request_specific_t specific_type, va_list arguments);
+static herr_t H5VL__request_optional(void *req, const H5VL_class_t *cls,
+    va_list arguments);
+static herr_t H5VL__request_free(void *req, const H5VL_class_t *cls);
 
 
 /*********************/
@@ -5594,9 +5602,45 @@ done:
 
 
 /*-------------------------------------------------------------------------
- * Function:    H5VL_request_cancel
+ * Function:    H5VL__request_wait
  *
- * Purpose:     Cancels an asynchronous request through the VOL
+ * Purpose:     Waits on an asychronous request through the VOL
+ *
+ * Return:      Success:    Non-negative
+ *              Failure:    Negative
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+H5VL__request_wait(void *req, const H5VL_class_t *cls, uint64_t timeout,
+    H5ES_status_t *status)
+{
+    herr_t ret_value = SUCCEED;         /* Return value */
+
+    FUNC_ENTER_STATIC
+
+    /* Sanity checks */
+    HDassert(req);
+    HDassert(cls);
+    HDassert(status);
+
+    /* Check if the corresponding VOL callback exists */
+    if(NULL == cls->request_cls.wait)
+        HGOTO_ERROR(H5E_VOL, H5E_UNSUPPORTED, FAIL, "VOL plugin has no 'async wait' method")
+
+    /* Call the corresponding VOL callback */
+    if((cls->request_cls.wait)(req, timeout, status) < 0)
+        HGOTO_ERROR(H5E_VOL, H5E_CANTRELEASE, FAIL, "request wait failed")
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5VL__request_wait() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:    H5VL_request_wait
+ *
+ * Purpose:     Waits on an asychronous request through the VOL
  *
  * Return:      Success:    Non-negative
  *              Failure:    Negative
@@ -5604,27 +5648,136 @@ done:
  *-------------------------------------------------------------------------
  */
 herr_t
-H5VL_request_cancel(void **req, const H5VL_class_t *cls, H5ES_status_t *status)
+H5VL_request_wait(const H5VL_object_t *vol_obj, uint64_t timeout,
+    H5ES_status_t *status)
 {
+    hbool_t vol_wrapper_set = FALSE;    /* Whether the VOL object wrapping context was set up */
     herr_t ret_value = SUCCEED;         /* Return value */
 
     FUNC_ENTER_NOAPI(FAIL)
 
+    /* Sanity checks */
+    HDassert(vol_obj);
+
+    /* Set wrapper info in API context */
+    if(H5VL_set_vol_wrapper(vol_obj->data, vol_obj->plugin) < 0)
+        HGOTO_ERROR(H5E_VOL, H5E_CANTSET, FAIL, "can't set VOL wrapper info")
+    vol_wrapper_set = TRUE;
+
+    /* Call the corresponding internal VOL routine */
+    if(H5VL__request_wait(vol_obj->data, vol_obj->plugin->cls, timeout, status) < 0)
+        HGOTO_ERROR(H5E_VOL, H5E_CANTRELEASE, FAIL, "request wait failed")
+
+done:
+    /* Reset object wrapping info in API context */
+    if(vol_wrapper_set && H5VL_reset_vol_wrapper() < 0)
+        HDONE_ERROR(H5E_VOL, H5E_CANTRESET, FAIL, "can't reset VOL wrapper info")
+
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5VL_request_wait() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:    H5VLrequest_wait
+ *
+ * Purpose:     Waits on a request
+ *
+ * Return:      Success:    Non-negative
+ *              Failure:    Negative
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5VLrequest_wait(void *req, hid_t plugin_id, uint64_t timeout, H5ES_status_t *status)
+{
+    H5VL_class_t *cls;                  /* VOL plugin's class struct */
+    herr_t ret_value = SUCCEED;         /* Return value */
+
+    FUNC_ENTER_API_NOINIT
+
+    /* Get class pointer */
+    if(NULL == (cls = (H5VL_class_t *)H5I_object_verify(plugin_id, H5I_VOL)))
+        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not a VOL plugin ID")
+
+    /* Call the corresponding internal VOL routine */
+    if(H5VL__request_wait(req, cls, timeout, status) < 0)
+        HGOTO_ERROR(H5E_VOL, H5E_CANTRELEASE, FAIL, "unable to wait on request")
+
+done:
+    FUNC_LEAVE_API_NOINIT(ret_value)
+} /* end H5VLrequest_wait() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:    H5VL__request_cancel
+ *
+ * Purpose:     Cancels an asynchronous request through the VOL
+ *
+ * Return:      Success:    Non-negative
+ *              Failure:    Negative
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+H5VL__request_cancel(void *req, const H5VL_class_t *cls)
+{
+    herr_t ret_value = SUCCEED;         /* Return value */
+
+    FUNC_ENTER_STATIC
+
     /* Sanity check */
     HDassert(req);
     HDassert(cls);
-    HDassert(status);
 
     /* Check if the corresponding VOL callback exists */
-    if(NULL == cls->async_cls.cancel)
+    if(NULL == cls->request_cls.cancel)
         HGOTO_ERROR(H5E_VOL, H5E_UNSUPPORTED, FAIL, "VOL plugin has no 'async cancel' method")
 
     /* Call the corresponding VOL callback */
-    if((cls->async_cls.cancel)(req, status) < 0)
+    if((cls->request_cls.cancel)(req) < 0)
         HGOTO_ERROR(H5E_VOL, H5E_CANTRELEASE, FAIL, "request cancel failed")
 
 done:
     FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5VL__request_cancel() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:    H5VL_request_cancel
+ *
+ * Purpose:     Cancels an asynchronous request through the VOL
+ *
+ * Return:      Success:    Non-negative
+ *              Failure:    Negative
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5VL_request_cancel(const H5VL_object_t *vol_obj)
+{
+    hbool_t vol_wrapper_set = FALSE;    /* Whether the VOL object wrapping context was set up */
+    herr_t ret_value = SUCCEED;         /* Return value */
+
+    FUNC_ENTER_NOAPI(FAIL)
+
+    /* Sanity check */
+    HDassert(vol_obj);
+
+    /* Set wrapper info in API context */
+    if(H5VL_set_vol_wrapper(vol_obj->data, vol_obj->plugin) < 0)
+        HGOTO_ERROR(H5E_VOL, H5E_CANTSET, FAIL, "can't set VOL wrapper info")
+    vol_wrapper_set = TRUE;
+
+    /* Call the corresponding internal VOL routine */
+    if(H5VL__request_cancel(vol_obj->data, vol_obj->plugin->cls) < 0)
+        HGOTO_ERROR(H5E_VOL, H5E_CANTRELEASE, FAIL, "request cancel failed")
+
+done:
+    /* Reset object wrapping info in API context */
+    if(vol_wrapper_set && H5VL_reset_vol_wrapper() < 0)
+        HDONE_ERROR(H5E_VOL, H5E_CANTRESET, FAIL, "can't reset VOL wrapper info")
+
+    FUNC_LEAVE_NOAPI(ret_value)
 } /* end H5VL_request_cancel() */
 
 
@@ -5639,20 +5792,20 @@ done:
  *-------------------------------------------------------------------------
  */
 herr_t
-H5VLrequest_cancel(void **req, hid_t plugin_id, H5ES_status_t *status)
+H5VLrequest_cancel(void *req, hid_t plugin_id)
 {
     H5VL_class_t *cls;                  /* VOL plugin's class struct */
     herr_t ret_value = SUCCEED;         /* Return value */
 
     FUNC_ENTER_API_NOINIT
-    H5TRACE3("e", "**xi*Es", req, plugin_id, status);
+    H5TRACE2("e", "*xi", req, plugin_id);
 
     /* Get class pointer */
     if(NULL == (cls = (H5VL_class_t *)H5I_object_verify(plugin_id, H5I_VOL)))
         HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not a VOL plugin ID")
 
     /* Call the corresponding internal VOL routine */
-    if(H5VL_request_cancel(req, cls, status) < 0)
+    if(H5VL__request_cancel(req, cls) < 0)
         HGOTO_ERROR(H5E_VOL, H5E_CANTRELEASE, FAIL, "unable to cancel request")
 
 done:
@@ -5661,44 +5814,44 @@ done:
 
 
 /*-------------------------------------------------------------------------
- * Function:    H5VL_request_test
+ * Function:    H5VL__request_specific
  *
- * Purpose:     Tests an asynchronous request through the VOL
+ * Purpose:	Specific operation on asynchronous request through the VOL
  *
  * Return:      Success:    Non-negative
  *              Failure:    Negative
  *
  *-------------------------------------------------------------------------
  */
-herr_t
-H5VL_request_test(void **req, const H5VL_class_t *cls, H5ES_status_t *status)
+static herr_t
+H5VL__request_specific(void *req, const H5VL_class_t *cls,
+    H5VL_request_specific_t specific_type, va_list arguments)
 {
     herr_t ret_value = SUCCEED;         /* Return value */
 
-    FUNC_ENTER_NOAPI(FAIL)
+    FUNC_ENTER_STATIC
 
-    /* Sanity checks */
+    /* Sanity check */
     HDassert(req);
     HDassert(cls);
-    HDassert(status);
 
     /* Check if the corresponding VOL callback exists */
-    if(NULL == cls->async_cls.test)
-        HGOTO_ERROR(H5E_VOL, H5E_UNSUPPORTED, FAIL, "VOL plugin has no 'async test' method")
+    if(NULL == cls->request_cls.specific)
+        HGOTO_ERROR(H5E_VOL, H5E_UNSUPPORTED, FAIL, "VOL plugin has no 'async specific' method")
 
     /* Call the corresponding VOL callback */
-    if((cls->async_cls.test)(req, status) < 0)
-        HGOTO_ERROR(H5E_VOL, H5E_CANTGET, FAIL, "request test failed")
+    if((ret_value = (cls->request_cls.specific)(req, specific_type, arguments)) < 0)
+        HGOTO_ERROR(H5E_VOL, H5E_CANTOPERATE, FAIL, "unable to execute asynchronous request specific callback")
 
 done:
     FUNC_LEAVE_NOAPI(ret_value)
-} /* end H5VL_request_test() */
+} /* end H5VL__request_specific() */
 
 
 /*-------------------------------------------------------------------------
- * Function:    H5VLrequest_test
+ * Function:    H5VL_request_specific
  *
- * Purpose:     Tests a request
+ * Purpose:	Specific operation on asynchronous request through the VOL
  *
  * Return:      Success:    Non-negative
  *              Failure:    Negative
@@ -5706,31 +5859,113 @@ done:
  *-------------------------------------------------------------------------
  */
 herr_t
-H5VLrequest_test(void **req, hid_t plugin_id, H5ES_status_t *status)
+H5VL_request_specific(const H5VL_object_t *vol_obj,
+    H5VL_request_specific_t specific_type, ...)
+{
+    va_list arguments;                  /* Argument list passed from the API call */
+    hbool_t arg_started = FALSE;        /* Whether the va_list has been started */
+    hbool_t vol_wrapper_set = FALSE;    /* Whether the VOL object wrapping context was set up */
+    herr_t ret_value = SUCCEED;         /* Return value */
+
+    FUNC_ENTER_NOAPI(FAIL)
+
+    /* Sanity check */
+    HDassert(vol_obj);
+
+    /* Set wrapper info in API context */
+    if(H5VL_set_vol_wrapper(vol_obj->data, vol_obj->plugin) < 0)
+        HGOTO_ERROR(H5E_VOL, H5E_CANTSET, FAIL, "can't set VOL wrapper info")
+    vol_wrapper_set = TRUE;
+
+    /* Call the corresponding internal VOL routine */
+    va_start(arguments, specific_type);
+    arg_started = TRUE;
+    if((ret_value = H5VL__request_specific(vol_obj->data, vol_obj->plugin->cls, specific_type, arguments)) < 0)
+        HGOTO_ERROR(H5E_VOL, H5E_CANTOPERATE, FAIL, "unable to execute asynchronous request specific callback")
+
+done:
+    /* End access to the va_list, if we started it */
+    if(arg_started)
+        va_end(arguments);
+
+    /* Reset object wrapping info in API context */
+    if(vol_wrapper_set && H5VL_reset_vol_wrapper() < 0)
+        HDONE_ERROR(H5E_VOL, H5E_CANTRESET, FAIL, "can't reset VOL wrapper info")
+
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5VL_request_specific() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:    H5VLrequest_specific
+ *
+ * Purpose:     Performs a plugin-specific operation on an asynchronous request
+ *
+ * Return:      Success:    Non-negative
+ *              Failure:    Negative
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5VLrequest_specific(void *req, hid_t plugin_id, H5VL_request_specific_t specific_type,
+    va_list arguments)
 {
     H5VL_class_t *cls;                  /* VOL plugin's class struct */
     herr_t ret_value = SUCCEED;         /* Return value */
 
     FUNC_ENTER_API_NOINIT
-    H5TRACE3("e", "**xi*Es", req, plugin_id, status);
 
     /* Get class pointer */
     if(NULL == (cls = (H5VL_class_t *)H5I_object_verify(plugin_id, H5I_VOL)))
         HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not a VOL plugin ID")
 
     /* Call the corresponding internal VOL routine */
-    if(H5VL_request_test(req, cls, status) < 0)
-        HGOTO_ERROR(H5E_VOL, H5E_CANTGET, FAIL, "unable to test request")
+    if((ret_value = H5VL__request_specific(req, cls, specific_type, arguments)) < 0)
+        HGOTO_ERROR(H5E_VOL, H5E_CANTOPERATE, FAIL, "unable to execute asynchronous request specific callback")
 
 done:
     FUNC_LEAVE_API_NOINIT(ret_value)
-} /* end H5VLrequest_test() */
+} /* end H5VLrequest_specific() */
 
 
 /*-------------------------------------------------------------------------
- * Function:    H5VL_request_wait
+ * Function:    H5VL__request_optional
  *
- * Purpose:     Waits on an asychronous request through the VOL
+ * Purpose:	Optional operation specific to plugins.
+ *
+ * Return:      Success:    Non-negative
+ *              Failure:    Negative
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+H5VL__request_optional(void *req, const H5VL_class_t *cls, va_list arguments)
+{
+    herr_t ret_value = SUCCEED;         /* Return value */
+
+    FUNC_ENTER_STATIC
+
+    /* Sanity check */
+    HDassert(req);
+    HDassert(cls);
+
+    /* Check if the corresponding VOL callback exists */
+    if(NULL == cls->request_cls.optional)
+        HGOTO_ERROR(H5E_VOL, H5E_UNSUPPORTED, FAIL, "VOL plugin has no 'async optional' method")
+
+    /* Call the corresponding VOL callback */
+    if((ret_value = (cls->request_cls.optional)(req, arguments)) < 0)
+        HGOTO_ERROR(H5E_VOL, H5E_CANTOPERATE, FAIL, "unable to execute asynchronous request optional callback")
+
+done:
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5VL__request_optional() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:    H5VL_request_optional
+ *
+ * Purpose:	Optional operation specific to plugins.
  *
  * Return:      Success:    Non-negative
  *              Failure:    Negative
@@ -5738,34 +5973,150 @@ done:
  *-------------------------------------------------------------------------
  */
 herr_t
-H5VL_request_wait(void **req, const H5VL_class_t *cls, H5ES_status_t *status)
+H5VL_request_optional(const H5VL_object_t *vol_obj, ...)
 {
+    va_list arguments;                  /* Argument list passed from the API call */
+    hbool_t arg_started = FALSE;        /* Whether the va_list has been started */
+    hbool_t vol_wrapper_set = FALSE;    /* Whether the VOL object wrapping context was set up */
     herr_t ret_value = SUCCEED;         /* Return value */
 
     FUNC_ENTER_NOAPI(FAIL)
 
-    /* Sanity checks */
+    /* Sanity check */
+    HDassert(vol_obj);
+
+    /* Set wrapper info in API context */
+    if(H5VL_set_vol_wrapper(vol_obj->data, vol_obj->plugin) < 0)
+        HGOTO_ERROR(H5E_VOL, H5E_CANTSET, FAIL, "can't set VOL wrapper info")
+    vol_wrapper_set = TRUE;
+
+    /* Call the corresponding internal VOL routine */
+    va_start(arguments, vol_obj);
+    arg_started = TRUE;
+    if((ret_value = H5VL__request_optional(vol_obj->data, vol_obj->plugin->cls, arguments)) < 0)
+        HGOTO_ERROR(H5E_VOL, H5E_CANTOPERATE, FAIL, "unable to execute asynchronous request optional callback")
+
+done:
+    /* End access to the va_list, if we started it */
+    if(arg_started)
+        va_end(arguments);
+
+    /* Reset object wrapping info in API context */
+    if(vol_wrapper_set && H5VL_reset_vol_wrapper() < 0)
+        HDONE_ERROR(H5E_VOL, H5E_CANTRESET, FAIL, "can't reset VOL wrapper info")
+
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5VL_request_optional() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:    H5VLrequest_optional
+ *
+ * Purpose:     Performs an optional plugin-specific operation on an asynchronous request
+ *
+ * Return:      Success:    Non-negative
+ *              Failure:    Negative
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5VLrequest_optional(void *req, hid_t plugin_id, va_list arguments)
+{
+    H5VL_class_t *cls;                  /* VOL plugin's class struct */
+    herr_t ret_value = SUCCEED;         /* Return value */
+
+    FUNC_ENTER_API_NOINIT
+
+    /* Get class pointer */
+    if(NULL == (cls = (H5VL_class_t *)H5I_object_verify(plugin_id, H5I_VOL)))
+        HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not a VOL plugin ID")
+
+    /* Call the corresponding internal VOL routine */
+    if((ret_value = H5VL__request_optional(req, cls, arguments)) < 0)
+        HGOTO_ERROR(H5E_VOL, H5E_CANTOPERATE, FAIL, "unable to execute asynchronous request optional callback")
+
+done:
+    FUNC_LEAVE_API_NOINIT(ret_value)
+} /* end H5VLrequest_optional() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:    H5VL__request_free
+ *
+ * Purpose:     Frees an asynchronous request through the VOL
+ *
+ * Return:      Success:    Non-negative
+ *              Failure:    Negative
+ *
+ *-------------------------------------------------------------------------
+ */
+static herr_t
+H5VL__request_free(void *req, const H5VL_class_t *cls)
+{
+    herr_t ret_value = SUCCEED;         /* Return value */
+
+    FUNC_ENTER_STATIC
+
+    /* Sanity check */
     HDassert(req);
     HDassert(cls);
-    HDassert(status);
 
     /* Check if the corresponding VOL callback exists */
-    if(NULL == cls->async_cls.wait)
-        HGOTO_ERROR(H5E_VOL, H5E_UNSUPPORTED, FAIL, "VOL plugin has no 'async wait' method")
+    if(NULL == cls->request_cls.free)
+        HGOTO_ERROR(H5E_VOL, H5E_UNSUPPORTED, FAIL, "VOL plugin has no 'async free' method")
 
     /* Call the corresponding VOL callback */
-    if((cls->async_cls.wait)(req, status) < 0)
-        HGOTO_ERROR(H5E_VOL, H5E_CANTRELEASE, FAIL, "request wait failed")
+    if((cls->request_cls.free)(req) < 0)
+        HGOTO_ERROR(H5E_VOL, H5E_CANTRELEASE, FAIL, "request free failed")
 
 done:
     FUNC_LEAVE_NOAPI(ret_value)
-} /* end H5VL_request_wait() */
+} /* end H5VL__request_free() */
 
 
 /*-------------------------------------------------------------------------
- * Function:    H5VLrequest_wait
+ * Function:    H5VL_request_free
  *
- * Purpose:     Waits on a request
+ * Purpose:     Frees an asynchronous request through the VOL
+ *
+ * Return:      Success:    Non-negative
+ *              Failure:    Negative
+ *
+ *-------------------------------------------------------------------------
+ */
+herr_t
+H5VL_request_free(const H5VL_object_t *vol_obj)
+{
+    hbool_t vol_wrapper_set = FALSE;    /* Whether the VOL object wrapping context was set up */
+    herr_t ret_value = SUCCEED;         /* Return value */
+
+    FUNC_ENTER_NOAPI(FAIL)
+
+    /* Sanity check */
+    HDassert(vol_obj);
+
+    /* Set wrapper info in API context */
+    if(H5VL_set_vol_wrapper(vol_obj->data, vol_obj->plugin) < 0)
+        HGOTO_ERROR(H5E_VOL, H5E_CANTSET, FAIL, "can't set VOL wrapper info")
+    vol_wrapper_set = TRUE;
+
+    /* Call the corresponding VOL callback */
+    if(H5VL__request_free(vol_obj->data, vol_obj->plugin->cls) < 0)
+        HGOTO_ERROR(H5E_VOL, H5E_CANTRELEASE, FAIL, "request free failed")
+
+done:
+    /* Reset object wrapping info in API context */
+    if(vol_wrapper_set && H5VL_reset_vol_wrapper() < 0)
+        HDONE_ERROR(H5E_VOL, H5E_CANTRESET, FAIL, "can't reset VOL wrapper info")
+
+    FUNC_LEAVE_NOAPI(ret_value)
+} /* end H5VL_request_free() */
+
+
+/*-------------------------------------------------------------------------
+ * Function:    H5VLrequest_free
+ *
+ * Purpose:     Frees a request
  *
  * Return:      Success:    Non-negative
  *              Failure:    Negative
@@ -5773,23 +6124,23 @@ done:
  *-------------------------------------------------------------------------
  */
 herr_t
-H5VLrequest_wait(void **req, hid_t plugin_id, H5ES_status_t *status)
+H5VLrequest_free(void *req, hid_t plugin_id)
 {
     H5VL_class_t *cls;                  /* VOL plugin's class struct */
     herr_t ret_value = SUCCEED;         /* Return value */
 
     FUNC_ENTER_API_NOINIT
-    H5TRACE3("e", "**xi*Es", req, plugin_id, status);
+    H5TRACE2("e", "*xi", req, plugin_id);
 
     /* Get class pointer */
     if(NULL == (cls = (H5VL_class_t *)H5I_object_verify(plugin_id, H5I_VOL)))
         HGOTO_ERROR(H5E_ARGS, H5E_BADTYPE, FAIL, "not a VOL plugin ID")
 
     /* Call the corresponding internal VOL routine */
-    if(H5VL_request_wait(req, cls, status) < 0)
-        HGOTO_ERROR(H5E_VOL, H5E_CANTRELEASE, FAIL, "unable to wait on request")
+    if(H5VL__request_free(req, cls) < 0)
+        HGOTO_ERROR(H5E_VOL, H5E_CANTRELEASE, FAIL, "unable to free request")
 
 done:
     FUNC_LEAVE_API_NOINIT(ret_value)
-} /* end H5VLrequest_wait() */
+} /* end H5VLrequest_free() */
 
diff --git a/src/H5VLnative.c b/src/H5VLnative.c
index c6954bc..9137e4d 100644
--- a/src/H5VLnative.c
+++ b/src/H5VLnative.c
@@ -192,10 +192,12 @@ static H5VL_class_t H5VL_native_cls_g = {
         H5VL__native_object_specific,               /* specific     */
         H5VL__native_object_optional                /* optional     */
     },
-    {   /* async_cls */
+    {   /* request_cls */
+        NULL,                                       /* wait         */
         NULL,                                       /* cancel       */
-        NULL,                                       /* test         */
-        NULL                                        /* wait         */
+        NULL,                                       /* specific     */
+        NULL,                                       /* optional     */
+        NULL                                        /* free         */
     },
     NULL                                            /* optional     */
 };
diff --git a/src/H5VLprivate.h b/src/H5VLprivate.h
index a168b57..ee6b7d4 100644
--- a/src/H5VLprivate.h
+++ b/src/H5VLprivate.h
@@ -162,9 +162,11 @@ H5_DLL herr_t H5VL_datatype_optional(const H5VL_object_t *vol_obj, hid_t dxpl_id
 H5_DLL herr_t H5VL_datatype_close(const H5VL_object_t *vol_obj, hid_t dxpl_id, void **req);
 
 /* Asynchronous functions */
-H5_DLL herr_t H5VL_request_cancel(void **req, const H5VL_class_t *cls, H5ES_status_t *status);
-H5_DLL herr_t H5VL_request_test(void **req, const H5VL_class_t *cls, H5ES_status_t *status);
-H5_DLL herr_t H5VL_request_wait(void **req, const H5VL_class_t *cls, H5ES_status_t *status);
+H5_DLL herr_t H5VL_request_wait(const H5VL_object_t *vol_obj, uint64_t timeout, H5ES_status_t *status);
+H5_DLL herr_t H5VL_request_cancel(const H5VL_object_t *vol_obj);
+H5_DLL herr_t H5VL_request_specific(const H5VL_object_t *vol_obj, H5VL_request_specific_t specific_type, ...);
+H5_DLL herr_t H5VL_request_optional(const H5VL_object_t *vol_obj, ...);
+H5_DLL herr_t H5VL_request_free(const H5VL_object_t *vol_obj);
 
 #endif /* _H5VLprivate_H */
 
diff --git a/src/H5VLpublic.h b/src/H5VLpublic.h
index 5d19985..1b8a4a7 100644
--- a/src/H5VLpublic.h
+++ b/src/H5VLpublic.h
@@ -169,14 +169,21 @@ typedef enum H5VL_object_get_t {
 
 /* types for object SPECIFIC callback */
 typedef enum H5VL_object_specific_t {
-    H5VL_OBJECT_CHANGE_REF_COUNT,      /* H5Oincr/decr_refcount              */
-    H5VL_OBJECT_EXISTS,                /* H5Oexists_by_name                  */
-    H5VL_OBJECT_VISIT,                 /* H5Ovisit(_by_name)                 */
-    H5VL_REF_CREATE,                   /* H5Rcreate                          */
-    H5VL_OBJECT_FLUSH,
-    H5VL_OBJECT_REFRESH
+    H5VL_OBJECT_CHANGE_REF_COUNT,       /* H5Oincr/decr_refcount             */
+    H5VL_OBJECT_EXISTS,                 /* H5Oexists_by_name                 */
+    H5VL_OBJECT_VISIT,                  /* H5Ovisit(_by_name)                */
+    H5VL_REF_CREATE,                    /* H5Rcreate                         */
+    H5VL_OBJECT_FLUSH,                  /* H5{D|G|O|T}flush                  */
+    H5VL_OBJECT_REFRESH                 /* H5{D|G|O|T}refresh                */
 } H5VL_object_specific_t;
 
+/* types for async request SPECIFIC callback */
+typedef enum H5VL_request_specific_t {
+    H5VL_REQUEST_WAITANY,               /* Wait until any request completes */
+    H5VL_REQUEST_WAITSOME,              /* Wait until at least one requesst completes */
+    H5VL_REQUEST_WAITALL                /* Wait until all requests complete */
+} H5VL_request_specific_t;
+
 /* types for different ways that objects are located in an HDF5 container */
 typedef enum H5VL_loc_type_t {
     H5VL_OBJECT_BY_SELF,
@@ -329,11 +336,13 @@ typedef struct H5VL_object_class_t {
 } H5VL_object_class_t;
 
 /* Async operation routines */
-typedef struct H5VL_async_class_t {
-    herr_t (*cancel)(void **, H5ES_status_t *);
-    herr_t (*test)  (void **, H5ES_status_t *);
-    herr_t (*wait)  (void **, H5ES_status_t *);
-} H5VL_async_class_t;
+typedef struct H5VL_request_class_t {
+    herr_t (*wait)(void *req, uint64_t timeout, H5ES_status_t *status);
+    herr_t (*cancel)(void *req);
+    herr_t (*specific)(void *req, H5VL_request_specific_t specific_type, va_list arguments);
+    herr_t (*optional)(void *req, va_list arguments);
+    herr_t (*free)(void *req);
+} H5VL_request_class_t;
 
 
 /* enum value to identify the class of a VOL plugin (mostly for comparison purposes) */
@@ -389,7 +398,7 @@ typedef struct H5VL_class_t {
     H5VL_object_class_t        object_cls;          /* object class callbacks       */
 
     /* Services */
-    H5VL_async_class_t         async_cls;           /* asynchronous class callbacks */
+    H5VL_request_class_t       request_cls;         /* asynchronous request class callbacks */
 
     /* Catch-all */
     herr_t (*optional)(void *obj, hid_t dxpl_id, void **req, va_list arguments); /* Optional callback */
@@ -506,9 +515,11 @@ H5_DLL herr_t H5VLdatatype_optional(void *obj, hid_t plugin_id, hid_t dxpl_id, v
 H5_DLL herr_t H5VLdatatype_close(void *dt, hid_t plugin_id, hid_t dxpl_id, void **req);
 
 /* Public wrappers for asynchronous request callbacks */
-H5_DLL herr_t H5VLrequest_cancel(void **req, hid_t plugin_id, H5ES_status_t *status);
-H5_DLL herr_t H5VLrequest_test(void **req, hid_t plugin_id, H5ES_status_t *status);
-H5_DLL herr_t H5VLrequest_wait(void **req, hid_t plugin_id, H5ES_status_t *status);
+H5_DLL herr_t H5VLrequest_wait(void *req, hid_t plugin_id, uint64_t timeout, H5ES_status_t *status);
+H5_DLL herr_t H5VLrequest_cancel(void *req, hid_t plugin_id);
+H5_DLL herr_t H5VLrequest_specific(void *req, hid_t plugin_id, H5VL_request_specific_t specific_type, va_list arguments);
+H5_DLL herr_t H5VLrequest_optional(void *req, hid_t plugin_id, va_list arguments);
+H5_DLL herr_t H5VLrequest_free(void *req, hid_t plugin_id);
 
 #ifdef __cplusplus
 }
diff --git a/src/H5trace.c b/src/H5trace.c
index a63bdfa..797130e 100644
--- a/src/H5trace.c
+++ b/src/H5trace.c
@@ -834,8 +834,8 @@ H5_trace(const double *returning, const char *func, const char *type, ...)
                                 case H5ES_STATUS_FAIL:
                                     HDfprintf(out, "H5ES_STATUS_FAIL");
                                     break;
-                                case H5ES_STATUS_CANCEL:
-                                    HDfprintf(out, "H5ES_STATUS_CANCEL");
+                                case H5ES_STATUS_CANCELLED:
+                                    HDfprintf(out, "H5ES_STATUS_CANCELLED");
                                     break;
 
                                 default: