From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1761024AbZBLVbK (ORCPT ); Thu, 12 Feb 2009 16:31:10 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751238AbZBLVaz (ORCPT ); Thu, 12 Feb 2009 16:30:55 -0500 Received: from mx2.redhat.com ([66.187.237.31]:37336 "EHLO mx2.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750906AbZBLVaz (ORCPT ); Thu, 12 Feb 2009 16:30:55 -0500 Message-ID: <499494E2.3060006@redhat.com> Date: Thu, 12 Feb 2009 15:30:10 -0600 From: Eric Sandeen User-Agent: Thunderbird 2.0.0.19 (Macintosh/20081209) MIME-Version: 1.0 To: Jan Kara CC: =?ISO-8859-1?Q?Fernando_Luis_V=E1zquez_Cao?= , Theodore Tso , Alan Cox , Pavel Machek , kernel list , Jens Axboe , fernando@kic.ac.jp, Ric Wheeler Subject: Re: vfs: Add MS_FLUSHONFSYNC mount flag References: <1232114101.13775.63.camel@sebastian.kern.oss.ntt.co.jp> <20090116163039.GE10617@duck.suse.cz> <1232185639.4831.18.camel@sebastian.kern.oss.ntt.co.jp> <1232186449.4831.29.camel@sebastian.kern.oss.ntt.co.jp> <20090119120349.GA10193@duck.suse.cz> <1233135913.5399.57.camel@sebastian.kern.oss.ntt.co.jp> <20090128095518.GA16554@duck.suse.cz> <1234434811.15270.7.camel@sebastian.kern.oss.ntt.co.jp> <1234434970.15433.4.camel@sebastian.kern.oss.ntt.co.jp> <499458C1.90105@redhat.com> <20090212212304.GA7935@duck.suse.cz> In-Reply-To: <20090212212304.GA7935@duck.suse.cz> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Jan Kara wrote: > On Thu 12-02-09 11:13:37, Eric Sandeen wrote: ... >> Also that way if you have 8 partitions on a battery-backed blockdev, you >> can tune it once, instead of needing to mount all 8 filesystems with the >> new option. > Yes, but OTOH we should give sysadmin a possibility to enable / disable > it on just some partitions. I don't see a reasonable use for that but people > tend to do strange things ;) and here isn't probably a strong reason to not > allow them. > > Honza But nobody has asked for that, have they? So why offer it up a this point? They could use LD_PRELOAD to make fsync a no-op if they really don't care for it, I guess... though that's not easily per-fs either. But do we really want to go out of our way to enable people to short-circuit data integrity paths and then file bugs when their files go missing? :) (I guess the blockdev tunable is similarly dangerous, but it more clearly meets the explicit need (writecache-safe devices)) -Eric