diff --git a/include/linux/nfs_fs_sb.h b/include/linux/nfs_fs_sb.h
index 452d964..1eaa054 100644
--- a/include/linux/nfs_fs_sb.h
+++ b/include/linux/nfs_fs_sb.h
@@ -71,6 +71,7 @@
 	 */
 	char			cl_ipaddr[48];
 	unsigned char		cl_id_uniquifier;
+	u32			cl_cb_ident;	/* v4.0 callback identifier */
 	const struct nfs4_minor_version_ops *cl_mvops;
 #endif /* CONFIG_NFS_V4 */