Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932850AbZADART (ORCPT ); Sat, 3 Jan 2009 19:17:19 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1759988AbZADARH (ORCPT ); Sat, 3 Jan 2009 19:17:07 -0500 Received: from atrey.karlin.mff.cuni.cz ([195.113.26.193]:41519 "EHLO atrey.karlin.mff.cuni.cz" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756067AbZADARG (ORCPT ); Sat, 3 Jan 2009 19:17:06 -0500 Date: Sun, 4 Jan 2009 01:19:00 +0100 From: Pavel Machek To: Martin =?utf-8?Q?MOKREJ=C5=A0?= Cc: Duane Griffin , kernel list , Andrew Morton , tytso@mit.edu, mtk.manpages@gmail.com, rdunlap@xenotime.net, linux-doc@vger.kernel.org Subject: Re: document ext3 requirements Message-ID: <20090104001859.GH1666@elf.ucw.cz> References: <20090103123813.GA1512@ucw.cz> <495FD5D7.2040907@ribosome.natur.cuni.cz> <20090103222957.GG1666@elf.ucw.cz> <495FEE66.9080903@ribosome.natur.cuni.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <495FEE66.9080903@ribosome.natur.cuni.cz> X-Warning: Reading this can be dangerous to your mental health. User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2189 Lines: 51 On Sun 2009-01-04 00:01:58, Martin MOKREJŠ wrote: > Pavel Machek wrote: > > On Sat 2009-01-03 22:17:15, Duane Griffin wrote: > >> [Fixed top-posting] > >> > >> 2009/1/3 Martin MOKREJŠ : > >>> Pavel Machek wrote: > >>>> readonly mount does actually write to the media in some cases. Document that. > >>>> > >>> Can one avoid replay of the journal then if it would be unclean? > >>> Just curious. > >> Nope. If the underlying block device is read-only then mounting the > >> filesystem will fail. I tried to fix this some time ago, and have a > >> set of patches that almost always work, but "almost always" isn't good > >> enough. Unfortunately I never managed to figure out a way to finish it > >> off without disgusting hacks or major surgery. > > > > Uhuh, can you just ignore the journal and mount it anyway? > > ...basically treating it like an ext2? > > > > ...ok, that will present "old" version of the filesystem to the > > user... violating fsync() semantics. > > Hmm, so if my dual-boot machine does not shutdown correctly and I boot > accidentally in M$ Win where I use ext2 IFS driver and modify some > stuff on the ext3 drive, after a while reboot to linux and the journal > get re-played ... Mmm ... ext2 driver should refuse to mount dirty ext3 filesystem. (Linux ext2 driver does that). > > Still handy for recovering badly broken filesystems, I'd say. > > Me as well. How about improving you doc patch with some summary of > this thread (although it is probably not over yet)? ;-) Definitely, > a note that one can mount it as ext2 while read-only would be helpful > when doing some forensics on the disk. No, you can't mount unclean ext3 as an ext2; patch to do that would be possible but... I believe the patch is correct & useful. Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/