diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c
index 9f00853..387a489 100644
--- a/fs/ceph/mds_client.c
+++ b/fs/ceph/mds_client.c
@@ -860,8 +860,11 @@
 	/*
 	 * Serialize client metadata into waiting buffer space, using
 	 * the format that userspace expects for map<string, string>
+	 *
+	 * ClientSession messages with metadata are v2
 	 */
-	msg->hdr.version = 2;  /* ClientSession messages with metadata are v2 */
+	msg->hdr.version = cpu_to_le16(2);
+	msg->hdr.compat_version = cpu_to_le16(1);
 
 	/* The write pointer, following the session_head structure */
 	p = msg->front.iov_base + sizeof(*h);
@@ -1872,7 +1875,7 @@
 		goto out_free2;
 	}
 
-	msg->hdr.version = 2;
+	msg->hdr.version = cpu_to_le16(2);
 	msg->hdr.tid = cpu_to_le64(req->r_tid);
 
 	head = msg->front.iov_base;