Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752725AbXE3Kns (ORCPT ); Wed, 30 May 2007 06:43:48 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751535AbXE3Kni (ORCPT ); Wed, 30 May 2007 06:43:38 -0400 Received: from mx1.redhat.com ([66.187.233.31]:58152 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751483AbXE3Kng (ORCPT ); Wed, 30 May 2007 06:43:36 -0400 Date: Wed, 30 May 2007 11:41:15 +0100 From: Alasdair G Kergon To: device-mapper development Cc: Stefan Bader , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-raid@vger.kernel.org, Jens Axboe , David Chinner , Phillip Susi , Stefan Bader , Andreas Dilger , Tejun Heo Subject: Re: [dm-devel] Re: [RFD] BIO_RW_BARRIER - what it means for devices, filesystems, and dm/md. Message-ID: <20070530104115.GO25091@agk.fab.redhat.com> Mail-Followup-To: device-mapper development , Stefan Bader , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-raid@vger.kernel.org, Jens Axboe , David Chinner , Phillip Susi , Stefan Bader , Andreas Dilger , Tejun Heo References: <18006.38689.818186.221707@notabene.brown> <18010.12472.209452.148229@notabene.brown> <20070528094358.GM25091@agk.fab.redhat.com> <5201e28f0705290225v14fdac44hb0382a4137a84d01@mail.gmail.com> <20070529220500.GA6513@agk.fab.redhat.com> <5201e28f0705300212g3be16464u5ee1a4c80db27a11@mail.gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <5201e28f0705300212g3be16464u5ee1a4c80db27a11@mail.gmail.com> User-Agent: Mutt/1.4.1i Organization: Red Hat UK Ltd. Registered in England and Wales, number 03798903. Registered Office: Amberley Place, 107-111 Peascod Street, Windsor, Berkshire, SL4 1TE. Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 576 Lines: 16 On Wed, May 30, 2007 at 11:12:37AM +0200, Stefan Bader wrote: > it might be better to indicate -EOPNOTSUPP right from > device-mapper. Indeed we should. For support, on receipt of a barrier, dm core should send a zero-length barrier to all active underlying paths, and delay mapping any further I/O. Alasdair -- agk@redhat.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/