From: Mark Fasheh Subject: Re: [Cluster-devel] fallocate vs O_(D)SYNC Date: Wed, 16 Nov 2011 11:35:40 -0800 Message-ID: <20111116193540.GL23779@wotan.suse.de> References: <20111116084256.GA22963@infradead.org> <1321436588.2713.5.camel@menhir> <20111116105413.GA2916@quack.suse.cz> <20111116124550.GA11650@infradead.org> <20111116133915.GD8195@quack.suse.cz> <20111116134234.GA24258@infradead.org> <20111116155755.GA22284@quack.suse.cz> <20111116161806.GP29279@shiny> Reply-To: Mark Fasheh Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii To: Chris Mason , Jan Kara , Christoph Hellwig , Steven Whitehouse , linux-btrfs@vger.kernel.org, linux-ext4@ Return-path: Received: from cantor2.suse.de ([195.135.220.15]:48694 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751442Ab1KPTfm (ORCPT ); Wed, 16 Nov 2011 14:35:42 -0500 Content-Disposition: inline In-Reply-To: <20111116161806.GP29279@shiny> Sender: linux-ext4-owner@vger.kernel.org List-ID: On Wed, Nov 16, 2011 at 11:18:06AM -0500, Chris Mason wrote: > On Wed, Nov 16, 2011 at 04:57:55PM +0100, Jan Kara wrote: > > On Wed 16-11-11 08:42:34, Christoph Hellwig wrote: > > > On Wed, Nov 16, 2011 at 02:39:15PM +0100, Jan Kara wrote: > > > > > This would work fine with XFS and be equivalent to what it does for > > > > > O_DSYNC now. But I'd rather see every filesystem do the right thing > > > > > and make sure the update actually is on disk when doing O_(D)SYNC > > > > > operations. > > > > OK, I don't really have a strong opinion here. Are you afraid that just > > > > calling fsync() need not be enough to push all updates fallocate did to > > > > disk? > > > > > > No, the point is that you should not have to call fsync when doing > > > O_SYNC I/O. That's the whole point of it. > > I agree with you that userspace shouldn't have to call fsync. What I > > meant is that sys_fallocate() or do_fallocate() can call > > generic_write_sync(file, pos, len), and that would be completely > > transparent to userspace. > > We should do it per FS though, I'll patch up btrfs. I agree about doing it per FS. Ocfs2 just needs a one-liner to mark the journal transaction as synchronous. --Mark -- Mark Fasheh