ceph: fix list_add in ceph_put_snap_realm

Signed-off-by: Henry C Chang <henry.cy.chang@gmail.com>
Signed-off-by: Sage Weil <sage@newdream.net>

fs/ceph/snap.c

@@ -206,7 +206,7 @@ void ceph_put_snap_realm(struct ceph_mds_client *mdsc,
 		up_write(&mdsc->snap_rwsem);
 	} else {
 		spin_lock(&mdsc->snap_empty_lock);
-		list_add(&mdsc->snap_empty, &realm->empty_item);
+		list_add(&realm->empty_item, &mdsc->snap_empty);
 		spin_unlock(&mdsc->snap_empty_lock);
 	}
 }