From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dave Chinner Subject: Re: [RFC][PATCH] PM / Sleep: Freeze filesystems during system suspend/hibernation Date: Thu, 19 Dec 2013 11:22:16 +1100 Message-ID: <20131219002216.GT31386@dastard> References: <201202172159.15396.rjw@sisk.pl> <201205252113.50900.rjw@sisk.pl> <20131217230843.GA2911@amd.pavel.ucw.cz> <20131217233152.GC20579@dastard> <20131218000128.GA3737@amd.pavel.ucw.cz> <20131218123952.GI31386@dastard> <20131218140842.GA20488@amd.pavel.ucw.cz> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Josh Boyer , "Rafael J. Wysocki" , Linux PM list , LKML , Jan Kara , linux-fsdevel@vger.kernel.org, Nigel Cunningham , "Srivatsa S. Bhat" To: Pavel Machek Return-path: Received: from ipmail07.adl2.internode.on.net ([150.101.137.131]:47639 "EHLO ipmail07.adl2.internode.on.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751367Ab3LSAWW (ORCPT ); Wed, 18 Dec 2013 19:22:22 -0500 Content-Disposition: inline In-Reply-To: <20131218140842.GA20488@amd.pavel.ucw.cz> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: On Wed, Dec 18, 2013 at 03:08:42PM +0100, Pavel Machek wrote: > > > > I disagree - given the problem it is resolving leads to silent > > > > filesystem corruption, this patch should be considered somewhat of a > > > > priority to push... > > > > > > Umm. Ok, I forgot what it does, really. > > > > It ensures that the filesystem is in an quiescent state both in > > memory and on disk, and it cannot be modified in memory or on disk > > whilst the suspend image is being generated, or by log recovery > > after a resume before the suspended image has been restored. > > If someone attempts to run log recovery before resume, that's a bug > and yes, it will corrupt filesystems. (Including ext3). Don't do that. Freezing the filesystem prevents that accidental mount of the filesystem from being an issue. It fixes a bug that: > Documentation/power/swsusp.txt: > > * BIG FAT WARNING > ********************************************************* > * > * If you touch anything on disk between suspend and resume... > * ...kiss your data goodbye. Makes this a whole lot less dangerous. > > > So... for few years now suspend corrupts data on XFS? And Fedora has > > > the fix but it is not in mainline? That does not sound right... > > > > The issues freezing the filesystem before the suspend image is > > created affect every journalled filesystem linux supports, be > > it XFS, ext4, reiser, btrfs, etc. > > Did not it have some problems with ext3? Please read more carefully: "affect every journalled filesystem linux supports". So, ext3 is affected because it's a journalling filesystem. I didn't list every journalled filesystem Linux supports - "etc" means there are more examples that aren't explicitly listed. Cheers, Dave. -- Dave Chinner david@fromorbit.com