From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753731Ab1BNMCo (ORCPT ); Mon, 14 Feb 2011 07:02:44 -0500 Received: from ipmail06.adl6.internode.on.net ([150.101.137.145]:30175 "EHLO ipmail06.adl6.internode.on.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753423Ab1BNMCl (ORCPT ); Mon, 14 Feb 2011 07:02:41 -0500 X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: AvsEAPOlWE15LMsw/2dsb2JhbACmBXS5Og2FUQQ Date: Mon, 14 Feb 2011 23:02:37 +1100 From: Dave Chinner To: Tao Ma Cc: Christoph Hellwig , xfs@oss.sgi.com, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: XFS status update for January 2011 Message-ID: <20110214120237.GB13052@dastard> References: <20110213184219.GA22792@infradead.org> <4D5890B6.2090105@tao.ma> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4D5890B6.2090105@tao.ma> User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Feb 14, 2011 at 10:17:26AM +0800, Tao Ma wrote: > Hi Christoph, > On 02/14/2011 02:42 AM, Christoph Hellwig wrote: > >On the 4th of January we saw the release of Linux 2.6.37, which contains a > >large XFS update: > > > > 67 files changed, 1424 insertions(+), 1524 deletions(-) > > > >User visible changes are the new XFS_IOC_ZERO_RANGE ioctl which allows > >to convert already allocated space into unwritten extents that return > >zeros on a read, > would you mind describing some scenario that this ioctl can be used. I am > just wondering whether ocfs2 can implement it as well. Zeroing a file without doing IO or having to punch out the blocks already allocated to the file. In this case, we had a couple of different people in cloud storage land asking for such functionality to optimise record deletion be avoiding disruption of their preallocated file layouts as a punch-then-preallocate operation does. If you you have some kind of use for it in ocfs2, then implementing the XFS ioctl is not the correct thing to do - using the fallocate patch I've had sitting around (since about 15min after creating the XFS ioctl) is most likely the right way to proceed.... Cheers, Dave. -- Dave Chinner david@fromorbit.com