-#define mfs_lock ((int (*) __P((struct vop_lock_args *)))nullop)
-#define mfs_unlock ((int (*) __P((struct vop_unlock_args *)))nullop)
-#define mfs_islocked ((int (*) __P((struct vop_islocked_args *)))nullop)
+#define mfs_lock ((int (*) __P((struct vop_lock_args *)))vop_nolock)
+#define mfs_unlock ((int (*) __P((struct vop_unlock_args *)))vop_nounlock)
+#define mfs_islocked ((int(*) __P((struct vop_islocked_args *)))vop_noislocked)