diff --git a/fs/ceph/ceph_fs.h b/fs/ceph/ceph_fs.h
index acf24c6..b3bbab1 100644
--- a/fs/ceph/ceph_fs.h
+++ b/fs/ceph/ceph_fs.h
@@ -72,7 +72,9 @@
 	__le32 fl_pg_pool;      /* namespace, crush ruleset, rep level */
 } __attribute__ ((packed));
 
+#define CEPH_MIN_STRIPE_UNIT 65536
 
+int ceph_file_layout_is_valid(const struct ceph_file_layout *layout);
 
 
 /*********************************************