3743 zfs needs a refcount audit
Submitted by:   Will Andrews <willa@spectralogic.com>
Submitted by:   Justin Gibbs <justing@spectralogic.com>
Reviewed by:    Matthew Ahrens <mahrens@delphix.com>

@@ -354,12 +354,14 @@
         if (err != 0)
                 return (err);
 
         /* Make sure dsobj has the correct object type. */
         dmu_object_info_from_db(dbuf, &doi);
-        if (doi.doi_type != DMU_OT_DSL_DATASET)
+        if (doi.doi_type != DMU_OT_DSL_DATASET) {
+                dmu_buf_rele(dbuf, tag);
                 return (SET_ERROR(EINVAL));
+        }
 
         ds = dmu_buf_get_user(dbuf);
         if (ds == NULL) {
                 dsl_dataset_t *winner = NULL;