From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756578Ab1EYHqV (ORCPT ); Wed, 25 May 2011 03:46:21 -0400 Received: from cantor2.suse.de ([195.135.220.15]:46984 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755901Ab1EYHqU convert rfc822-to-8bit (ORCPT ); Wed, 25 May 2011 03:46:20 -0400 From: Oliver Neukum Organization: SUSE To: Dave Chinner Subject: Re: [rfc] Ignore Fsync Calls in Laptop_Mode Date: Wed, 25 May 2011 08:50:11 +0200 User-Agent: KMail/1.13.5 (Linux/2.6.39-rc4-12-desktop+; KDE/4.4.4; x86_64; ; ) Cc: "D. Jansen" , linux-kernel@vger.kernel.org, akpm@linux-foundation.org, tytso@mit.edu References: <201105231012.06928.oneukum@suse.de> <20110525000003.GJ32466@dastard> In-Reply-To: <20110525000003.GJ32466@dastard> MIME-Version: 1.0 Content-Type: Text/Plain; charset="iso-8859-1" Content-Transfer-Encoding: 8BIT Message-Id: <201105250850.12179.oneukum@suse.de> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Am Mittwoch, 25. Mai 2011, 02:00:03 schrieb Dave Chinner: > Oh, you're talking about application level write ordering. IO > "ordering" in filesystem speak is about guaranteeing the order of > data vs metadata writes for ensuring consistency after a crash > (e.g. ext3/4 default "data=ordered" mode). that's what I was > refering to, not anythign to do with applications. > > Besides, having to work out how to handle subtle application write > ordering bugs because you changed fsync semantics is simply another > reason for not changing behaviour in the first place. Sure. I'd say changing the behavior is right out. The question is whether we want an additional "superlaptop"-mode. And even in this case it seems to me that fsync() cannot be reduced to a nop because of ordering constraints. But perhaps we should then consider exporting an ordering primitive to user space. Regards Oliver -- - - - SUSE LINUX Products GmbH, GF: Jeff Hawn, Jennifer Guild, Felix Imendörffer, HRB 16746 (AG Nürnberg) Maxfeldstraße 5 90409 Nürnberg Germany - - -