diff --git a/include/linux/ceph/ceph_fs.h b/include/linux/ceph/ceph_fs.h
index f96de8d..f4b2ee1 100644
--- a/include/linux/ceph/ceph_fs.h
+++ b/include/linux/ceph/ceph_fs.h
@@ -653,6 +653,9 @@
 
 extern const char *ceph_cap_op_name(int op);
 
+/* flags field in client cap messages (version >= 10) */
+#define CEPH_CLIENT_CAPS_SYNC	(0x1)
+
 /*
  * caps message, used for capability callbacks, acks, requests, etc.
  */