From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965285AbWGJW2X (ORCPT ); Mon, 10 Jul 2006 18:28:23 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S965283AbWGJW2W (ORCPT ); Mon, 10 Jul 2006 18:28:22 -0400 Received: from mail.tmr.com ([64.65.253.246]:12724 "EHLO gaimboi.tmr.com") by vger.kernel.org with ESMTP id S965282AbWGJW2U (ORCPT ); Mon, 10 Jul 2006 18:28:20 -0400 Message-ID: <44B2D6AA.3090707@tmr.com> Date: Mon, 10 Jul 2006 18:37:30 -0400 From: Bill Davidsen Organization: TMR Associates Inc, Schenectady NY User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.7.11) Gecko/20050729 X-Accept-Language: en-us, en MIME-Version: 1.0 To: Trond Myklebust CC: "J. Bruce Fields" , Theodore Tso , Thomas Glanzmann , LKML Subject: Re: ext4 features 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> In-Reply-To: <1152562135.6220.7.camel@lade.trondhjem.org> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org 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. -- bill davidsen CTO TMR Associates, Inc Doing interesting things with small computers since 1979