From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jeff Garzik Subject: Re: notes on volatile write caches vs fdatasync Date: Thu, 27 Aug 2009 15:26:24 -0400 Message-ID: <4A96DDE0.9090306@garzik.org> References: <20090827011624.GA10405@lst.de> <20090827130252.GC14240@duck.novell.com> <20090827184948.GA1367@lst.de> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: Jan Kara , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, chris.mason@oracle.com, tytso@mit.edu, adilger@sun.com, swhiteho@redhat.com, konishi.ryusuke@lab.ntt.co.jp, mfasheh@suse.com, joel.becker@oracle.com To: Christoph Hellwig Return-path: Received: from srv5.dvmed.net ([207.36.208.214]:34663 "EHLO mail.dvmed.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751168AbZH0T0d (ORCPT ); Thu, 27 Aug 2009 15:26:33 -0400 In-Reply-To: <20090827184948.GA1367@lst.de> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: On 08/27/2009 02:49 PM, Christoph Hellwig wrote: > On Thu, Aug 27, 2009 at 03:02:52PM +0200, Jan Kara wrote: >> I've noticed this as well when we were tracking some problems Pavel >> Machek found with his USB stick. I even wrote a patch at the time >> http://osdir.com/ml/linux-ext4/2009-01/msg00015.html >> but it somehow died out. Now, the situation should be simpler with >> fsync paths cleaned up... BTW: People wanted this to be configurable per >> block device which probably makes sence... > > Yeah, that patch is pretty ugly. We need to do these cache flushes > in ->fsync (and ->sync_fs if any filesystem really doesn't guarantee to > issue transaction there after data has been written). Adding it > to simple_fsync too sounds good to me. Agreed. That was the direction I was heading with my patch[1]. Last feedback I got on that was needing to add a knob to optionally disable this new cache-flush behavior. Jeff [1] http://lkml.org/lkml/2009/3/27/366