From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758647Ab2KVWj0 (ORCPT ); Thu, 22 Nov 2012 17:39:26 -0500 Received: from mail.kernel.org ([198.145.19.201]:49013 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753549Ab2KVSdl (ORCPT ); Thu, 22 Nov 2012 13:33:41 -0500 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Greg Kroah-Hartman , alan@lxorguk.ukuu.org.uk, Josh Durgin , Alex Elder , Yehuda Sadeh Subject: [ 089/171] rbd: protect read of snapshot sequence number Date: Wed, 21 Nov 2012 16:40:35 -0800 Message-Id: <20121122004042.293678656@linuxfoundation.org> X-Mailer: git-send-email 1.8.0.197.g5a90748 In-Reply-To: <20121122004033.298367941@linuxfoundation.org> References: <20121122004033.298367941@linuxfoundation.org> User-Agent: quilt/0.60-2.1.2 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Josh Durgin (cherry picked from commit 403f24d3d51760a8b9368d595fa5f48c309f1a0f) This is updated whenever a snapshot is added or deleted, and the snapc pointer is changed with every refresh of the header. Signed-off-by: Josh Durgin Reviewed-by: Alex Elder Reviewed-by: Yehuda Sadeh Signed-off-by: Greg Kroah-Hartman --- drivers/block/rbd.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) --- a/drivers/block/rbd.c +++ b/drivers/block/rbd.c @@ -1683,7 +1683,9 @@ static int rbd_header_add_snap(struct rb 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: