From: Jan Kara Subject: Re: [Cluster-devel] fallocate vs O_(D)SYNC Date: Wed, 16 Nov 2011 14:39:15 +0100 Message-ID: <20111116133915.GD8195@quack.suse.cz> References: <20111116084256.GA22963@infradead.org> <1321436588.2713.5.camel@menhir> <20111116105413.GA2916@quack.suse.cz> <20111116124550.GA11650@infradead.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Jan Kara , Steven Whitehouse , linux-btrfs@vger.kernel.org, linux-ext4@vger.kernel.org, mfasheh@suse.com, jlbec@evilplan.org, cluster-devel@redhat.com To: Christoph Hellwig Return-path: Received: from cantor2.suse.de ([195.135.220.15]:45718 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756864Ab1KPNj2 (ORCPT ); Wed, 16 Nov 2011 08:39:28 -0500 Content-Disposition: inline In-Reply-To: <20111116124550.GA11650@infradead.org> Sender: linux-ext4-owner@vger.kernel.org List-ID: On Wed 16-11-11 07:45:50, Christoph Hellwig wrote: > On Wed, Nov 16, 2011 at 11:54:13AM +0100, Jan Kara wrote: > > Yeah, only that nobody calls that fsync() automatically if the fd is > > O_SYNC if I'm right. But maybe calling fdatasync() on the range which was > > fallocated from sys_fallocate() if the fd is O_SYNC would do the trick for > > most filesystems? That would match how we treat O_SYNC for other operations > > as well. I'm just not sure whether XFS wouldn't take unnecessarily big hit > > with this. > > 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? Honza -- Jan Kara SUSE Labs, CR