From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965083AbWGKCgr (ORCPT ); Mon, 10 Jul 2006 22:36:47 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S965085AbWGKCgr (ORCPT ); Mon, 10 Jul 2006 22:36:47 -0400 Received: from pat.uio.no ([129.240.10.4]:13440 "EHLO pat.uio.no") by vger.kernel.org with ESMTP id S965083AbWGKCgq (ORCPT ); Mon, 10 Jul 2006 22:36:46 -0400 Subject: Re: ext4 features From: Trond Myklebust To: Bill Davidsen Cc: "J. Bruce Fields" , Theodore Tso , Thomas Glanzmann , LKML In-Reply-To: <44B2D6AA.3090707@tmr.com> References: <20060701163301.GB24570@cip.informatik.uni-erlangen.de> <20060704010240.GD6317@thunk.org> <44ABAF7D.8010200@tmr.com> <20060705125956.GA529@fieldses.org> <1152128033.22345.17.camel@lade.trondhjem.org> <44AC2D9A.7020401@tmr.com> <1152135740.22345.42.camel@lade.trondhjem.org> <44B01DEF.9070607@tmr.com> <1152562135.6220.7.camel@lade.trondhjem.org> <44B2D6AA.3090707@tmr.com> Content-Type: text/plain Date: Mon, 10 Jul 2006 22:36:23 -0400 Message-Id: <1152585383.10156.9.camel@lade.trondhjem.org> Mime-Version: 1.0 X-Mailer: Evolution 2.6.1 Content-Transfer-Encoding: 7bit X-UiO-Spam-info: not spam, SpamAssassin (score=-5, required 12, autolearn=disabled, UIO_MAIL_IS_INTERNAL -5.00) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 2006-07-10 at 18:37 -0400, Bill Davidsen wrote: > Trond Myklebust wrote: > > >On Sat, 2006-07-08 at 17:04 -0400, Bill Davidsen wrote: > > > > > >>No, I didn't quite mean a manual touch, but a system call to "close and > >>set time to high resolution" for files where time uniformity is > >>important. Consider that in most cases the inodes times are set by the > >>host machine clock, which I close the change reflects the fileserving > >>host idea of time. If there were a call to close a file and set the > >>times like touch, then that could be used, for both local and network files. > >> > >> > > > >Close should never update the time since that would be a violation of > >POSIX rules. Normally, an NFS client will never need to update the time: > >RPC calls like WRITE, READ and SETATTR will automatically do it for us > >whenever necessary. > > > > > > Let me restate this a third time in another way. What I suggest is a > system call, NOT NAMED CLOSE, which does a close and touch. This was all > blue sky discussion, new system calls are as valid as nanosecond > resolution and syncronization between servers. Since this is a new call > it is not specified by POSIX. > > And Linus has already suggested that he would accept something similar, > when I proposed something like "noatime" mounts, which only updated > atime and mtime on open and close, to keep metadata relevant but not > have the overhead of constant updates. > > Actually, now that I have more free time I may revisit that idea. Linus might accept it, but I won't. It is totally unnecessary. Cheers, Trond