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/nfs4_fs.h b/fs/nfs/nfs4_fs.h
index cee8714..deaf37f 100644
--- a/fs/nfs/nfs4_fs.h
+++ b/fs/nfs/nfs4_fs.h
@@ -236,6 +236,7 @@
 extern int nfs4_server_capabilities(struct nfs_server *server, struct nfs_fh *fhandle);
 extern int nfs4_proc_fs_locations(struct inode *dir, const struct qstr *name,
 		struct nfs4_fs_locations *fs_locations, struct page *page);
+extern void nfs4_release_lockowner(const struct nfs4_lock_state *);
 
 #if defined(CONFIG_NFS_V4_1)
 static inline struct nfs4_session *nfs4_get_session(const struct nfs_server *server)