From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753258AbYLZSV7 (ORCPT ); Fri, 26 Dec 2008 13:21:59 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751085AbYLZSVv (ORCPT ); Fri, 26 Dec 2008 13:21:51 -0500 Received: from BISCAYNE-ONE-STATION.MIT.EDU ([18.7.7.80]:32791 "EHLO biscayne-one-station.mit.edu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751032AbYLZSVu (ORCPT ); Fri, 26 Dec 2008 13:21:50 -0500 Date: Fri, 26 Dec 2008 13:21:45 -0500 From: Theodore Tso To: Andreas Sundstrom Cc: linux-kernel@vger.kernel.org Subject: Re: 2.6.28 ext4, xen and lvm volume becomes ro after snapshot Message-ID: <20081226182145.GP9871@mit.edu> Mail-Followup-To: Theodore Tso , Andreas Sundstrom , linux-kernel@vger.kernel.org References: <4954BAAB.9090108@zappa.cx> <20081226140721.GN9871@mit.edu> <4954FB62.4090306@zappa.cx> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4954FB62.4090306@zappa.cx> User-Agent: Mutt/1.5.17+20080114 (2008-01-14) X-Spam-Flag: NO X-Spam-Score: 0.00 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hmm... ok, to summarize, you are seeing this problem with 2.6.28 (have you tried earlier kernel versions) when an LVM volume has a read/only snapshot in existence and you try to mount the LVM volume using ext4. If you mount the same LVM volume using ext3, you don't see any problems. Is that correct? Can you try mounting ext3 with barriers enabled? Booting with the command linux option rootflags=barriers should do the trick. If that fails, then it would indicate that trying to enable barriers in a Xen guest while the host OS has created a snapshot of volume causes an I/O error, thus leading errors which you are seeing. - Ted