From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932322AbWGEFNW (ORCPT ); Wed, 5 Jul 2006 01:13:22 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932349AbWGEFNW (ORCPT ); Wed, 5 Jul 2006 01:13:22 -0400 Received: from terminus.zytor.com ([192.83.249.54]:62933 "EHLO terminus.zytor.com") by vger.kernel.org with ESMTP id S932322AbWGEFNV (ORCPT ); Wed, 5 Jul 2006 01:13:21 -0400 Message-ID: <44AB4A68.90301@zytor.com> Date: Tue, 04 Jul 2006 22:13:12 -0700 From: "H. Peter Anvin" User-Agent: Thunderbird 1.5.0.4 (X11/20060614) MIME-Version: 1.0 To: Bill Davidsen CC: Benny Amorsen , linux-kernel@vger.kernel.org Subject: Re: ext4 features References: <20060701163301.GB24570@cip.informatik.uni-erlangen.de> <20060701170729.GB8763@irc.pl> <20060701174716.GC24570@cip.informatik.uni-erlangen.de> <20060701181702.GC8763@irc.pl> <20060703202219.GA9707@aitel.hist.no> <20060703205523.GA17122@irc.pl> <1151960503.3108.55.camel@laptopd505.fenrus.org> <44A9904F.7060207@wolfmountaingroup.com> <20060703232547.2d54ab9b.diegocg@gmail.com> <44AB3E4C.2000407@tmr.com> In-Reply-To: <44AB3E4C.2000407@tmr.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Bill Davidsen wrote: >> >> DC> Easily doable in userspace, why bother with kernel programming >> >> In userspace you can't automatically delete the files when the space >> becomes needed. The LD_PRELOAD/glibc methods also have the >> disadvantage of having to figure out where a file goes when it's >> deleted, depending on which device it happens to reside on. Demanding >> read access to /proc/mounts just to do rm could cause problems. >> >> Userspace has had 10 years to invent a good solution. If it was so >> easy, it would probably have been done. >> > Actually, if it were so important it WOULD have been done. I suspect > that the issue is not lack of a good solution, but lack of a good > problem. The behavior you propose requires a lot of kernel cleverness, > including make the inodes seem to go away, so the count is "right" for > what the user sees. > The real solution for it is snapshots. -hpa