From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S265296AbTLaXso (ORCPT ); Wed, 31 Dec 2003 18:48:44 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S265297AbTLaXso (ORCPT ); Wed, 31 Dec 2003 18:48:44 -0500 Received: from h68-147-142-75.cg.shawcable.net ([68.147.142.75]:3325 "EHLO schatzie.adilger.int") by vger.kernel.org with ESMTP id S265296AbTLaXsn (ORCPT ); Wed, 31 Dec 2003 18:48:43 -0500 Date: Wed, 31 Dec 2003 16:48:24 -0700 From: Andreas Dilger To: viro@parcelfarce.linux.theplanet.co.uk Cc: Rob Love , Nathan Conrad , Pascal Schmidt , linux-kernel@vger.kernel.org, Greg KH Subject: Re: udev and devfs - The final word Message-ID: <20031231164824.I6144@schatzie.adilger.int> Mail-Followup-To: viro@parcelfarce.linux.theplanet.co.uk, Rob Love , Nathan Conrad , Pascal Schmidt , linux-kernel@vger.kernel.org, Greg KH References: <18Cz7-7Ep-7@gated-at.bofh.it> <20031231192306.GG25389@kroah.com> <1072901961.11003.14.camel@fur> <20031231220107.GC11032@bungled.net> <1072909218.11003.24.camel@fur> <20031231225536.GP4176@parcelfarce.linux.theplanet.co.uk> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.2.5.1i In-Reply-To: <20031231225536.GP4176@parcelfarce.linux.theplanet.co.uk>; from viro@parcelfarce.linux.theplanet.co.uk on Wed, Dec 31, 2003 at 10:55:36PM +0000 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 Dec 31, 2003 22:55 +0000, viro@parcelfarce.linux.theplanet.co.uk wrote: > h) nfsd uses device number as a substitute for export ID if said > ID is not given explicitly. That, BTW, is a big problem for crackpipe > dreams about random device numbers - export ID _must_ be stable across > reboots. We had a problem with this and Lustre, when we NFS export it. Lustre is already a network filesystem so we don't have a device number. I had a discussion with Neil Brown about this and suggested that we allow NFS to get a _real_ stable export ID from the filesystem (e.g. superblock UUID or similar) instead of the device number hackery which only has a vague relationship to stable. We implemented it for Lustre with a filesystem option FS_NFSEXP_FSID that tells nfsd it can export such a filesystem in the absence of FS_REQUIRES_DEV and then put our export ID into sb->s_dev (although I'd prefer something slightly cleaner than that). Cheers, Andreas -- Andreas Dilger http://sourceforge.net/projects/ext2resize/ http://www-mddsp.enel.ucalgary.ca/People/adilger/