Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757933AbYF3Ght (ORCPT ); Mon, 30 Jun 2008 02:37:49 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753443AbYF3Ghk (ORCPT ); Mon, 30 Jun 2008 02:37:40 -0400 Received: from gw.goop.org ([64.81.55.164]:46520 "EHLO mail.goop.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752826AbYF3Ghj (ORCPT ); Mon, 30 Jun 2008 02:37:39 -0400 Message-ID: <48687F2B.2000402@goop.org> Date: Sun, 29 Jun 2008 23:37:31 -0700 From: Jeremy Fitzhardinge User-Agent: Thunderbird 2.0.0.14 (X11/20080501) MIME-Version: 1.0 To: xfs-masters@oss.sgi.com, Elias Oltmanns , Henrique de Moraes Holschuh , Kyle Moffett , Matthew Garrett , David Chinner , Jeremy Fitzhardinge , Linux Kernel Mailing List , Jens Axboe Subject: Re: [xfs-masters] Re: freeze vs freezer References: <4744FD87.7010301@goop.org> <20080626150910.GK5642@ucw.cz> <20080629221217.GM29319@disturbed> <200806300122.48204.rjw@sisk.pl> <20080630062956.GN29319@disturbed> In-Reply-To: <20080630062956.GN29319@disturbed> X-Enigmail-Version: 0.95.6 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2116 Lines: 49 Dave Chinner wrote: > On Mon, Jun 30, 2008 at 01:22:47AM +0200, Rafael J. Wysocki wrote: > >> On Monday, 30 of June 2008, Dave Chinner wrote: >> >>> On Thu, Jun 26, 2008 at 05:09:10PM +0200, Pavel Machek wrote: >>> >>>>>> Is this the same thing the per-device IO-queue-freeze patches for >>>>>> HDAPS also >>>>>> need to do? If so, you may want to talk to Elias Oltmanns >>>>>> about it. Added to CC. >>>>>> >>>>> Thanks for the heads up Henrique. Even though these issues seem to be >>>>> related up to a certain degree, there probably are some important >>>>> differences. When suspending a system, the emphasis is on leaving the >>>>> system in a consistent state (think of journalled file systems), whereas >>>>> disk shock protection is mainly concerned with stopping I/O as soon as >>>>> possible. As yet, I cannot possibly say to what extend these two >>>>> concepts can be reconciled in the sense of sharing some common code. >>>>> >>>> Actually, I believe requirements are same. >>>> >>>> 'don't do i/o in dangerous period'. >>>> >>>> swsusp will just do sync() before entering dangerous period. That >>>> provides consistent-enough state... >>>> >>> As I've said many times before - if the requirement is "don't do >>> I/O" then you have to freeze the filesystem. In no way does 'sync' >>> prevent filesystems from doing I/O..... >>> >> Well, it seems we can handle this on the block layer level, by temporarily >> replacing the elevator with something that will selectively prevent fs I/O >> from reaching the layers below it. >> > > Why? What part of freeze_bdev() doesn't work for you? Well, my original problem - which is still an issue - is that a process writing to a frozen XFS filesystem is stuck in D state, and therefore cannot be frozen as part of suspend. J -- 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/