Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932838AbWKJKkG (ORCPT ); Fri, 10 Nov 2006 05:40:06 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932846AbWKJKkF (ORCPT ); Fri, 10 Nov 2006 05:40:05 -0500 Received: from gprs189-60.eurotel.cz ([160.218.189.60]:14720 "EHLO amd.ucw.cz") by vger.kernel.org with ESMTP id S932838AbWKJKkD (ORCPT ); Fri, 10 Nov 2006 05:40:03 -0500 Date: Fri, 10 Nov 2006 11:39:42 +0100 From: Pavel Machek To: David Chinner Cc: "Rafael J. Wysocki" , Alasdair G Kergon , Eric Sandeen , Andrew Morton , linux-kernel@vger.kernel.org, dm-devel@redhat.com, Srinivasa DS , Nigel Cunningham Subject: Re: [PATCH 2.6.19 5/5] fs: freeze_bdev with semaphore not mutex Message-ID: <20061110103942.GG3196@elf.ucw.cz> References: <20061107183459.GG6993@agk.surrey.redhat.com> <200611092218.58970.rjw@sisk.pl> <20061109214159.GB2616@elf.ucw.cz> <200611092321.47728.rjw@sisk.pl> <20061110005749.GO8394166@melbourne.sgi.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20061110005749.GO8394166@melbourne.sgi.com> X-Warning: Reading this can be dangerous to your mental health. User-Agent: Mutt/1.5.11+cvs20060126 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1196 Lines: 25 On Fri 2006-11-10 11:57:49, David Chinner wrote: > On Thu, Nov 09, 2006 at 11:21:46PM +0100, Rafael J. Wysocki wrote: > > I think we can add a flag to __create_workqueue() that will indicate if > > this one is to be running with PF_NOFREEZE and a corresponding macro like > > create_freezable_workqueue() to be used wherever we want the worker thread > > to freeze (in which case it should be calling try_to_freeze() somewhere). > > Then, we can teach filesystems to use this macro instead of > > create_workqueue(). > > At what point does the workqueue get frozen? i.e. how does this > guarantee an unfrozen filesystem will end up in a consistent > state? Snapshot is atomic; workqueue will be unfrozen with everyone else, but as there were no writes in the meantime, there should be no problems. 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/