Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753743AbXECLXY (ORCPT ); Thu, 3 May 2007 07:23:24 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753865AbXECLXX (ORCPT ); Thu, 3 May 2007 07:23:23 -0400 Received: from smtp-vbr15.xs4all.nl ([194.109.24.35]:1950 "EHLO smtp-vbr15.xs4all.nl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753743AbXECLXW (ORCPT ); Thu, 3 May 2007 07:23:22 -0400 From: "Miquel van Smoorenburg" To: adilger@clusterfs.com Cc: linux-kernel@vger.kernel.org Subject: Re: [PATCH 0/5] fallocate system call X-Newsgroups: lists.linux.kernel In-Reply-To: <20070503103425.GE6220@schatzie.adilger.int> References: <20070330071417.GI355@devserv.devel.redhat.com> <20070417125514.GA7574@amitarora.in.ibm.com> <20070418130600.GW5967@schatzie.adilger.int> <20070420135146.GA21352@amitarora.in.ibm.com> <20070420145918.GY355@devserv.devel.redhat.com> <20070424121632.GA10136@amitarora.in.ibm.com> <20070426175056.GA25321@amitarora.in.ibm.com> <20070430004702.GM32602149@melbourne.sgi.com> <20070430052559.GA13145@tuatara.stupidest.org> <20070502125312.GA5845@amitarora.in.ibm.com> Organization: Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7BIT Message-Id: Date: Thu, 03 May 2007 13:22:48 +0200 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1682 Lines: 37 In article <20070503103425.GE6220@schatzie.adilger.int> you write: >On May 02, 2007 18:23 +0530, Amit K. Arora wrote: >> On Sun, Apr 29, 2007 at 10:25:59PM -0700, Chris Wedgwood wrote: >> > On Mon, Apr 30, 2007 at 10:47:02AM +1000, David Chinner wrote: >> > >> > > For FA_ALLOCATE, it's supposed to change the file size if we >> > > allocate past EOF, right? >> > >> > I would argue no. Use truncate for that. >> >> The patch I posted for ext4 *does* change the filesize after >> preallocation, if required (i.e. when preallocation is after EOF). >> I may have to change that, if we decide on not doing this. > >I think I'd agree - it may be useful to allow preallocation beyond EOF >for some kinds of applications (e.g. PVR preallocating live TV in 10 >minute segments or something, but not knowing in advance how long the >show will actually be recorded or the final encoded size). I have an application (diablo dreader) where the header-info database basically consists of ~40.000 files, one for each group (it's more complicated that that, but never mind that now). If you grow those files randomly by a few hundred bytes every update, the filesystem gets hopelessly fragmented. I'm using XFS with preallocation turned on, and biosize=18 (which makes it preallocate in blocks of 256KB), and a homebrew patch that leaves the preallocated space on disk preallocated even if the file is closed .. and it helps enormously. Mike. - 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/