From mboxrd@z Thu Jan 1 00:00:00 1970 From: Douglas Gilbert Subject: Re: [LSF/MM TOPIC] Sparseness in storage Date: Thu, 03 Feb 2011 09:40:25 -0500 Message-ID: <4D4ABE59.5010409@interlog.com> References: <4D498F4B.3050207@interlog.com> <20110203022312.GA8529@infradead.org> Reply-To: dgilbert@interlog.com Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from smtp.infotech.no ([82.134.31.41]:56783 "EHLO smtp.infotech.no" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753283Ab1BCOka (ORCPT ); Thu, 3 Feb 2011 09:40:30 -0500 In-Reply-To: <20110203022312.GA8529@infradead.org> Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: Christoph Hellwig Cc: linux-scsi On 11-02-02 09:23 PM, Christoph Hellwig wrote: > On Wed, Feb 02, 2011 at 12:07:23PM -0500, Douglas Gilbert wrote: >> are improving their sparseness handling as well, with Linux >> playing "catch up" to NTFS in this regard (e.g. the new >> FALLOC_FL_PUNCH_HOLE flag in fallocate() ). > > FYI: XFS has supported hole punching for more than 15 years, although > the first years obviously were't on Linux. I was looking at the Windows API yesterday and you need to check each volume for sparse support. So it is file system dependent there as well: VFAT doesn't support sparseness and NTFS (version ?) does. From the perspective of user space tools, POSIX support for sparseness would be helpful and FALLOC_FL_PUNCH_HOLE looks like a step in that direction. Doug Gilbert