5056 ZFS deadlock on db_mtx and dn_holds
Reviewed by: Will Andrews <willa@spectralogic.com>
Reviewed by: Matt Ahrens <mahrens@delphix.com>
Reviewed by: George Wilson <george.wilson@delphix.com>
Approved by: Dan McDonald <danmcd@omniti.com>

@@ -350,11 +350,11 @@
         uint64_t zapobj;
         nvlist_t *holds_found;
         objset_t *mos;
         int numholds;
 
-        if (!dsl_dataset_is_snapshot(ds))
+        if (!ds->ds_is_snapshot)
                 return (SET_ERROR(EINVAL));
 
         if (nvlist_empty(holds))
                 return (0);