ceph: try to send partial cap release on cap message on missing inode

If we have enough memory to allocate a new cap release message, do so, so
that we can send a partial release message immediately.  This keeps us from
making the MDS wait when the cap release it needs is in a partially full
release message.

If we fail because of ENOMEM, oh well, they'll just have to wait a bit
longer.

Signed-off-by: Sage Weil <sage@newdream.net>

fs/ceph/caps.c

@@ -2708,6 +2708,7 @@ void ceph_handle_caps(struct ceph_mds_session *session,
 		 * along for the mds (who clearly thinks we still have this
 		 * cap).
 		 */
+		ceph_add_cap_releases(mdsc, session, -1);
 		ceph_send_cap_releases(mdsc, session);
 		goto done;
 	}