From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758609AbZC3TDW (ORCPT ); Mon, 30 Mar 2009 15:03:22 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1758289AbZC3TDB (ORCPT ); Mon, 30 Mar 2009 15:03:01 -0400 Received: from main.gmane.org ([80.91.229.2]:57288 "EHLO ciao.gmane.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758259AbZC3TDA (ORCPT ); Mon, 30 Mar 2009 15:03:00 -0400 X-Injected-Via-Gmane: http://gmane.org/ To: linux-kernel@vger.kernel.org From: Bill Davidsen Subject: Re: Linux 2.6.29 Date: Mon, 30 Mar 2009 15:02:44 -0400 Message-ID: References: <49CD7B10.7010601@garzik.org> <49CD891A.7030103@rtr.ca> <49CD9047.4060500@garzik.org> <49CE2633.2000903@s5r6.in-berlin.de> <49CE3186.8090903@garzik.org> <49CE35AE.1080702@s5r6.in-berlin.de> <49CE3F74.6090103@rtr.ca> <20090329231451.GR26138@disturbed> <20090330003948.GA13356@mit.edu> <49D0710A.1030805@ursus.ath.cx> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-Complaints-To: usenet@ger.gmane.org X-Gmane-NNTP-Posting-Host: pool-70-109-119-176.alb.east.verizon.net User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.8.1.19) Gecko/20081217 Fedora/1.1.14-1.fc9 SeaMonkey/1.1.14 In-Reply-To: <49D0710A.1030805@ursus.ath.cx> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Andreas T.Auer wrote: > On 30.03.2009 02:39 Theodore Tso wrote: >> All I can do is apologize to all other filesystem developers profusely >> for ext3's data=ordered semantics; at this point, I very much regret >> that we made data=ordered the default for ext3. But the application >> writers vastly outnumber us, and realistically we're not going to be >> able to easily roll back eight years of application writers being >> trained that fsync() is not necessary, and actually is detrimental for >> ext3. > And still I don't know any reason, why it makes sense to write the > metadata to non-existing data immediately instead of delaying that, too. > Here I have the same question, I don't expect or demand that anything be done in a particular order unless I force it so, and I expect there to be some corner case where the data is written and the metadata doesn't reflect that in the event of a failure, but I can't see that it ever a good idea to have the metadata reflect the future and describe what things will look like if everything goes as planned. I have had enough of that BS from financial planners and politicians, metadata shouldn't try to predict the future just to save a ms here or there. It's also necessary to have the metadata match reality after fsync(), of course, or even the well behaved applications mentioned in this thread haven't a hope of staying consistent. Feel free to clarify why clairvoyant metadata is ever a good thing... -- Bill Davidsen "We have more to fear from the bungling of the incompetent than from the machinations of the wicked." - from Slashdot