NFSv4: Add support for the RELEASE_LOCKOWNER operation

This is needed by NFSv4.0 servers in order to keep the number of locking
stateids at a manageable level.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
diff --git a/fs/nfs/nfs4state.c b/fs/nfs/nfs4state.c
index 13e17e3..13a4f27 100644
--- a/fs/nfs/nfs4state.c
+++ b/fs/nfs/nfs4state.c
@@ -701,6 +701,8 @@
 	if (list_empty(&state->lock_states))
 		clear_bit(LK_STATE_IN_USE, &state->flags);
 	spin_unlock(&state->state_lock);
+	if (lsp->ls_flags & NFS_LOCK_INITIALIZED)
+		nfs4_release_lockowner(lsp);
 	nfs4_free_lock_state(lsp);
 }