Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760279AbYBOOMv (ORCPT ); Fri, 15 Feb 2008 09:12:51 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755179AbYBOOMn (ORCPT ); Fri, 15 Feb 2008 09:12:43 -0500 Received: from mx1.redhat.com ([66.187.233.31]:60975 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759292AbYBOOMm (ORCPT ); Fri, 15 Feb 2008 09:12:42 -0500 Date: Fri, 15 Feb 2008 14:12:29 +0000 From: Alasdair G Kergon To: device-mapper development , Michael Tokarev , Andi Kleen , linux-kernel@vger.kernel.org Subject: Re: [dm-devel] Re: [PATCH] Implement barrier support for single device DM devices Message-ID: <20080215141229.GB1788@agk.fab.redhat.com> Mail-Followup-To: device-mapper development , Michael Tokarev , Andi Kleen , linux-kernel@vger.kernel.org References: <20080215120821.GA8267@basil.nowhere.org> <20080215122002.GM29914@agk.fab.redhat.com> <47B58EAA.8040405@msgid.tls.msk.ru> <20080215142010.GA29552@one.firstfloor.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20080215142010.GA29552@one.firstfloor.org> 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 List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 934 Lines: 22 On Fri, Feb 15, 2008 at 03:20:10PM +0100, Andi Kleen wrote: > On Fri, Feb 15, 2008 at 04:07:54PM +0300, Michael Tokarev wrote: > > I wonder if it's worth the effort to try to implement this. My personal view (which seems to be in the minority) is that it's a waste of our development time *except* in the (rare?) cases similar to the ones Andi is talking about. But the decision has already been made for us in the block layer: dm is now pretty much required to support (zero-length) barriers. Unfortunately we didn't get this finished in time for 2.6.25, but we intend to get it done for 2.6.26: Woe betide any callers today that don't handle EOPNOTSUPP! 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/