From: Avi Kivity Subject: Re: [PATCH 4/6] Ext4: fail if we try to use hole punch Date: Tue, 16 Nov 2010 15:07:29 +0200 Message-ID: <4CE28211.6060204@redhat.com> References: <1289840723-3056-1-git-send-email-josef@redhat.com> <1289840723-3056-5-git-send-email-josef@redhat.com> <4CE2783F.1020004@redhat.com> <20101116125016.GA31957@dhcp231-156.rdu.redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: david@fromorbit.com, linux-kernel@vger.kernel.org, linux-btrfs@vger.kernel.org, linux-ext4@vger.kernel.org, linux-fsdevel@vger.kernel.org, xfs@oss.sgi.com, cmm@us.ibm.com, cluster-devel@redhat.com, ocfs2-devel@oss.oracle.com To: Josef Bacik Return-path: Received: from mx1.redhat.com ([209.132.183.28]:50955 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756067Ab0KPNHq (ORCPT ); Tue, 16 Nov 2010 08:07:46 -0500 In-Reply-To: <20101116125016.GA31957@dhcp231-156.rdu.redhat.com> Sender: linux-ext4-owner@vger.kernel.org List-ID: On 11/16/2010 02:50 PM, Josef Bacik wrote: > On Tue, Nov 16, 2010 at 02:25:35PM +0200, Avi Kivity wrote: > > On 11/15/2010 07:05 PM, Josef Bacik wrote: > >> Ext4 doesn't have the ability to punch holes yet, so make sure we return > >> EOPNOTSUPP if we try to use hole punching through fallocate. This support can > >> be added later. Thanks, > >> > > > > Instead of teaching filesystems to fail if they don't support the > > capability, why don't supporting filesystems say so, allowing the fail > > code to be in common code? > > > > There is no simple way to test if a filesystem supports hole punching or not so > the check has to be done per fs. Thanks, Could put a flag word in superblock_operations. Filesystems which support punching (or other features) can enable it there. Or even have its own callback. -- error compiling committee.c: too many arguments to function