diff --git a/[refs] b/[refs]
index 3ef0550d9877..52209acf7397 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 50f7c4c967d0b5acd8e7ba6ab654dc4a7ac869ac
+refs/heads/master: 403f24d3d51760a8b9368d595fa5f48c309f1a0f
diff --git a/trunk/drivers/block/rbd.c b/trunk/drivers/block/rbd.c
index a75fe93a25b1..5ab9f55d3e0c 100644
--- a/trunk/drivers/block/rbd.c
+++ b/trunk/drivers/block/rbd.c
@@ -1684,7 +1684,9 @@ static int rbd_header_add_snap(struct rbd_device *dev,
 	if (ret < 0)
 		return ret;
 
-	dev->header.snapc->seq =  new_snapid;
+	down_write(&dev->header_rwsem);
+	dev->header.snapc->seq = new_snapid;
+	up_write(&dev->header_rwsem);
 
 	return 0;
 bad: