Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758019AbYF3Gae (ORCPT ); Mon, 30 Jun 2008 02:30:34 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1757617AbYF3GaK (ORCPT ); Mon, 30 Jun 2008 02:30:10 -0400 Received: from ipmail04.adl2.internode.on.net ([203.16.214.57]:49985 "EHLO ipmail04.adl2.internode.on.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755275AbYF3GaH (ORCPT ); Mon, 30 Jun 2008 02:30:07 -0400 X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: ApoEANexXkh5LFnm/2dsb2JhbACuPg X-IronPort-AV: E=Sophos;i="4.27,725,1204464600"; d="scan'208";a="146307951" Date: Mon, 30 Jun 2008 16:29:56 +1000 From: Dave Chinner To: xfs-masters@oss.sgi.com Cc: 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 Message-ID: <20080630062956.GN29319@disturbed> Mail-Followup-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 References: <4744FD87.7010301@goop.org> <20080626150910.GK5642@ucw.cz> <20080629221217.GM29319@disturbed> <200806300122.48204.rjw@sisk.pl> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <200806300122.48204.rjw@sisk.pl> User-Agent: Mutt/1.5.17+20080114 (2008-01-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1913 Lines: 44 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? Cheers, Dave. -- Dave Chinner david@fromorbit.com -- 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/