From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S936242AbXGSX6i (ORCPT ); Thu, 19 Jul 2007 19:58:38 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1759898AbXGSX63 (ORCPT ); Thu, 19 Jul 2007 19:58:29 -0400 Received: from mail.clusterfs.com ([74.0.229.162]:60931 "EHLO mail.clusterfs.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755289AbXGSX61 (ORCPT ); Thu, 19 Jul 2007 19:58:27 -0400 Date: Thu, 19 Jul 2007 17:58:25 -0600 From: Andreas Dilger To: Mark Fasheh Cc: "Amit K. Arora" , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-ext4@vger.kernel.org, xfs@oss.sgi.com, tytso@mit.edu, cmm@us.ibm.com, suparna@in.ibm.com, dgc@sgi.com, michael.kerrisk@gmx.net Subject: Re: [PATCH 1/5][TAKE8] manpage for fallocate Message-ID: <20070719235825.GY5992@schatzie.adilger.int> Mail-Followup-To: Mark Fasheh , "Amit K. Arora" , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-ext4@vger.kernel.org, xfs@oss.sgi.com, tytso@mit.edu, cmm@us.ibm.com, suparna@in.ibm.com, dgc@sgi.com, michael.kerrisk@gmx.net References: <20070713184125.GA12156@amitarora.in.ibm.com> <20070713184625.GB12156@amitarora.in.ibm.com> <20070719034155.GE32734@ca-server1.us.oracle.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20070719034155.GE32734@ca-server1.us.oracle.com> User-Agent: Mutt/1.4.1i X-GPG-Key: 1024D/0D35BED6 X-GPG-Fingerprint: 7A37 5D79 BF1B CECA D44F 8A29 A488 39F5 0D35 BED6 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Jul 18, 2007 20:41 -0700, Mark Fasheh wrote: > On Sat, Jul 14, 2007 at 12:16:25AM +0530, Amit K. Arora wrote: > > After a successful call, subsequent writes are guaranteed not to fail > > because of lack of disk space. > > If a write to an unwritten region requires a node split, that could result > in the allocation of new meta data which obviously could fail if the disk is > truly full. > > Granted that's unlikely to happen but maybe we should be conservative and > say something like: > > "After a successful call, subsequent writes are guaranteed to never require > allocation of file data." ? > --Mark In the worst case, the unwritten extent could be zero-filled before the write is done, so no exent split is needed. We discussed this recently for the ext4 fallocate, but didn't consider it important enough to hold the code. Cheers, Andreas -- Andreas Dilger Principal Software Engineer Cluster File Systems, Inc.