From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: with ECARTIS (v1.0.0; list xfs); Wed, 25 Oct 2006 01:48:42 -0700 (PDT) Received: from cuda.sgi.com (cuda1.sgi.com [192.48.168.28]) by oss.sgi.com (8.12.10/8.12.10/SuSE Linux 0.7) with ESMTP id k9P8mYaG032413 for ; Wed, 25 Oct 2006 01:48:35 -0700 Received: from amd.ucw.cz (gprs189-60.eurotel.cz [160.218.189.60]) by cuda.sgi.com (Spam Firewall) with ESMTP id BE4A94D7B83 for ; Wed, 25 Oct 2006 01:47:45 -0700 (PDT) Date: Wed, 25 Oct 2006 10:47:14 +0200 From: Pavel Machek Subject: Re: [PATCH] Freeze bdevs when freezing processes. Message-ID: <20061025084714.GA7266@elf.ucw.cz> References: <1161576735.3466.7.camel@nigel.suspend2.net> <200610231236.54317.rjw@sisk.pl> <20061024144446.GD11034@melbourne.sgi.com> <200610241730.00488.rjw@sisk.pl> <20061024163345.GG11034@melbourne.sgi.com> <20061024213737.GD5662@elf.ucw.cz> <20061025001331.GP8394166@melbourne.sgi.com> <20061025081001.GL5851@elf.ucw.cz> <20061025083830.GI11034@melbourne.sgi.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20061025083830.GI11034@melbourne.sgi.com> Sender: xfs-bounce@oss.sgi.com Errors-to: xfs-bounce@oss.sgi.com List-Id: xfs To: David Chinner Cc: "Rafael J. Wysocki" , Nigel Cunningham , Andrew Morton , LKML , xfs@oss.sgi.com On Wed 2006-10-25 18:38:30, David Chinner wrote: > On Wed, Oct 25, 2006 at 10:10:01AM +0200, Pavel Machek wrote: > > > Hence the only way to correctly rebuild the XFS state on resume is > > > to quiesce the filesystem on suspend and thaw it on resume so as to > > > trigger log recovery. > > > > No, during suspend/resume, memory image is saved, and no state is > > lost. We would not even have to do sys_sync(), and suspend/resume > > would still work properly. > > It seems to me that you ensure the filesystem is synced to disk and > then at some point later you record the memory state of the > filesystem, but these happen at different times. That leaves a > window for things to get out of sync again, right? I DO NOT HAVE TO ENSURE FILESYSTEM IS SYNCED. That sys_sync() is optional. Recording of memory state is atomic, and as long as noone writes to the disk after atomic snapshot, memory image matches what is on disk. Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html