From: Andrew Morton Subject: Re: [RFC, PATCH 0/6] ext3: do not modify data on-disk when mounting read-only filesystem Date: Wed, 5 Mar 2008 19:42:20 -0800 Message-ID: <20080305194220.f9cce55e.akpm@linux-foundation.org> References: <1204768754-29655-1-git-send-email-duaneg@dghda.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Cc: linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org, Theodore Tso , sct@redhat.com, adilger@clusterfs.com To: "Duane Griffin" Return-path: Received: from smtp1.linux-foundation.org ([140.211.169.13]:56465 "EHLO smtp1.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753619AbYCFDn5 (ORCPT ); Wed, 5 Mar 2008 22:43:57 -0500 In-Reply-To: <1204768754-29655-1-git-send-email-duaneg@dghda.com> Sender: linux-ext4-owner@vger.kernel.org List-ID: On Thu, 6 Mar 2008 01:59:08 +0000 "Duane Griffin" wrote: > At present, as discussed in this LKML thread, > http://marc.info/?l=linux-kernel&m=117607695406580, when a dirty ext3 > filesystem is mounted read-only it writes to the disk while replaying the > journal log and cleaning up the orphan list. This behaviour may surprise users > and can potentially cause data corruption/loss (e.g. if a system is suspended, > booted into a different OS, then resumed). > > This patch series attempts to address this by using a block translation table > instead of replaying the journal on a read-only filesystem. > > Patches 1-3 are independent cleanups/bug-fixes for things I came across while > working on this. They could be submitted separately and are not required for > following patches. > > Patch 4 is a refactoring change that simplifies the code prior to later > substantive changes. > > Patch 5 introduces the translation table and support for a truly read-only > journal into jbd. > > Patch 6 uses the facility introduced in patch 5 to add support for true > read-only ext3. I'll grab the first three for now, thanks. Someone(tm) should do the jbd2 versions..