Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1763048AbXFZXbn (ORCPT ); Tue, 26 Jun 2007 19:31:43 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1762417AbXFZX1T (ORCPT ); Tue, 26 Jun 2007 19:27:19 -0400 Received: from netops-testserver-3-out.sgi.com ([192.48.171.28]:57443 "EHLO relay.sgi.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1762507AbXFZX1Q (ORCPT ); Tue, 26 Jun 2007 19:27:16 -0400 Date: Wed, 27 Jun 2007 09:26:49 +1000 From: David Chinner To: "Amit K. Arora" , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-ext4@vger.kernel.org, David Chinner , suparna@in.ibm.com, cmm@us.ibm.com, xfs@oss.sgi.com Subject: Re: [PATCH 4/7][TAKE5] support new modes in fallocate Message-ID: <20070626232649.GR31489@sgi.com> References: <20070511110301.GB28425@in.ibm.com> <20070512080157.GF85884050@sgi.com> <20070612061652.GA6320@amitarora.in.ibm.com> <20070613235217.GS86004887@sgi.com> <20070614091458.GH5181@schatzie.adilger.int> <20070614120413.GD86004887@sgi.com> <20070614193347.GN5181@schatzie.adilger.int> <20070625132810.GA1951@amitarora.in.ibm.com> <20070625134500.GE1951@amitarora.in.ibm.com> <20070625215239.GK5181@schatzie.adilger.int> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20070625215239.GK5181@schatzie.adilger.int> User-Agent: Mutt/1.4.2.1i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1124 Lines: 30 On Mon, Jun 25, 2007 at 03:52:39PM -0600, Andreas Dilger wrote: > On Jun 25, 2007 19:15 +0530, Amit K. Arora wrote: > > +#define FA_FL_DEALLOC 0x01 /* default is allocate */ > > +#define FA_FL_KEEP_SIZE 0x02 /* default is extend/shrink size */ > > +#define FA_FL_DEL_DATA 0x04 /* default is keep written data on DEALLOC */ > > In XFS one of the (many) ALLOC modes is to zero existing data on allocate. No, none of the XFS allocation modes do that. XFS_IOC_ALLOCSP, which does write zeros to disk, only allocates and writes zeros in the range between the old file size and the new file size. XFS_IOC_RESVSP, which alocates unwritten extents, only allocates where extents do not currently exist. It does not zero existing extents. IOWs, you can't overwrite existing data with XFS preallocation. Cheers, Dave. -- Dave Chinner Principal Engineer SGI Australian Software Group - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/