3740 Poor ZFS send / receive performance due to snapshot hold / release processing
Submitted by: Steven Hartland <steven.hartland@multiplay.co.uk>

@@ -4978,20 +4978,10 @@
  */
 /* ARGSUSED */
 static int
 zfs_ioc_release(const char *pool, nvlist_t *holds, nvlist_t *errlist)
 {
-        nvpair_t *pair;
-
-        /*
-         * The release may cause the snapshot to be destroyed; make sure it
-         * is not mounted.
-         */
-        for (pair = nvlist_next_nvpair(holds, NULL); pair != NULL;
-            pair = nvlist_next_nvpair(holds, pair))
-                zfs_unmount_snap(nvpair_name(pair));
-
         return (dsl_dataset_user_release(holds, errlist));
 }
 
 /*
  * inputs: