From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S263415AbTJQSGP (ORCPT ); Fri, 17 Oct 2003 14:06:15 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S263491AbTJQSGP (ORCPT ); Fri, 17 Oct 2003 14:06:15 -0400 Received: from ns.virtualhost.dk ([195.184.98.160]:56712 "EHLO virtualhost.dk") by vger.kernel.org with ESMTP id S263415AbTJQSGN (ORCPT ); Fri, 17 Oct 2003 14:06:13 -0400 Date: Fri, 17 Oct 2003 20:06:12 +0200 From: Jens Axboe To: Manfred Spraul Cc: linux-kernel@vger.kernel.org Subject: Re: [PATCH] ide write barrier support Message-ID: <20031017180612.GB8230@suse.de> References: <3F902E0A.5060908@colorfullife.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <3F902E0A.5060908@colorfullife.com> X-OS: Linux 2.4.22aa1-axboe i686 User-Agent: Mutt/1.5.3i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Oct 17 2003, Manfred Spraul wrote: > Jens wrote: > > >The problem is that as far as I can see the best way to make fsync > >really work is to make the last write a barrier write. That > >automagically gets everything right for you - when the last block goes > >to disk, you know the previous ones have already. And when the last > >block completes, you know the whole lot is on platter. > > > Are you sure? > What prevents the io scheduler from writing the last block before other > blocks? Very sure, the io scheduler will never put the barrier write before previously comitted writes. So yes, it will work as described. Jens