Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1031349AbXEDHwJ (ORCPT ); Fri, 4 May 2007 03:52:09 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1030187AbXEDHwJ (ORCPT ); Fri, 4 May 2007 03:52:09 -0400 Received: from s2.ukfsn.org ([217.158.120.143]:55486 "EHLO mail.ukfsn.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S965706AbXEDHwH (ORCPT ); Fri, 4 May 2007 03:52:07 -0400 Message-ID: <463AE623.60501@dgreaves.com> Date: Fri, 04 May 2007 08:52:03 +0100 From: David Greaves User-Agent: Icedove 1.5.0.10 (X11/20070329) MIME-Version: 1.0 To: Kyle Moffett Cc: Pavel Machek , nigel@nigel.suspend2.net, Linus Torvalds , "Rafael J. Wysocki" , Pekka J Enberg , LKML Subject: Re: Back to the future. References: <1177567481.5025.211.camel@nigel.suspend2.net> <1177654110.4737.91.camel@nigel.suspend2.net> <200704272324.43359.rjw@sisk.pl> <1177711666.4737.176.camel@nigel.suspend2.net> <35EFC5BA-D16B-41BE-A641-AEA8CCC9E0BE@mac.com> <20070503151047.GB3866@ucw.cz> In-Reply-To: X-Enigmail-Version: 0.94.2.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1475 Lines: 33 Kyle Moffett wrote: > On May 03, 2007, at 11:10:47, Pavel Machek wrote: >> How mature is freezing filesystems -- will it work on at least ext2/3 >> and vfat? > > I'm pretty sure it works on ext2/3 and xfs and possibly others, I don't > know either way about VFAT though. Essentially the "freeze" part > involves telling the filesystem to sync all data, flush the journal, and > mark the filesystem clean. The intent under dm/LVM was to allow you to > make snapshots without having to fsck the just-created snapshot before > you mounted it. > >> What happens if you try to boot and filesystems are frozen from >> previous run? > > If you're just doing a fresh boot then the filesystem is already clean > due to the dm freeze and so it mounts up normally. All you need to do > then is have a little startup script which purges the saved image before > you fsck or remount things read-write since either case means the image > is no longer safe to resume. Wouldn't it be better if freeze wrote a freeze-ID to the fs and returned it? This would naturally be kept in the image and a UUID mismatch would be detectable - seems safer and more flexible than 'a script'. "This isn't the freeze you're looking for, move along" David - 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/