Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261272AbVA0XDu (ORCPT ); Thu, 27 Jan 2005 18:03:50 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261277AbVA0XBl (ORCPT ); Thu, 27 Jan 2005 18:01:41 -0500 Received: from parcelfarce.linux.theplanet.co.uk ([195.92.249.252]:39398 "EHLO parcelfarce.linux.theplanet.co.uk") by vger.kernel.org with ESMTP id S261262AbVA0XBQ (ORCPT ); Thu, 27 Jan 2005 18:01:16 -0500 Message-ID: <41F97299.2070909@pobox.com> Date: Thu, 27 Jan 2005 18:00:41 -0500 From: Jeff Garzik User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.7.3) Gecko/20040922 X-Accept-Language: en-us, en MIME-Version: 1.0 To: Doug Maxey , Jens Axboe CC: Linux Kernel , Bartlomiej Zolnierkiewicz , linux-scsi@vger.kernel.org Subject: Re: [PATCH] scsi/sata write barrier support References: <200501272242.j0RMgoP5016154@falcon30.maxeymade.com> In-Reply-To: <200501272242.j0RMgoP5016154@falcon30.maxeymade.com> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1043 Lines: 31 Doug Maxey wrote: > On Thu, 27 Jan 2005 13:02:48 +0100, Jens Axboe wrote: > >>Hi, >> >>For the longest time, only the old PATA drivers supported barrier writes >>with journalled file systems. This patch adds support for the same type >>of cache flushing barriers that PATA uses for SCSI, to be utilized with >>libata. > > > What, if any mechanism supports changing the underlying write cache? > > That is, assuming this is common across PATA and SCSI drives, and it is > possible to turn the cache off on the IDE drives, would switching the > cache underneath require completing the inflight IO? [ignoring your question, but it made me think...] I am thinking the barrier support should know if the write cache is disabled (some datacenters do this), and avoid flushing if so? Jeff - 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/