From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S265909AbUGZUUr (ORCPT ); Mon, 26 Jul 2004 16:20:47 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S265777AbUGZUSu (ORCPT ); Mon, 26 Jul 2004 16:18:50 -0400 Received: from dh132.citi.umich.edu ([141.211.133.132]:42133 "EHLO lade.trondhjem.org") by vger.kernel.org with ESMTP id S265879AbUGZThe convert rfc822-to-8bit (ORCPT ); Mon, 26 Jul 2004 15:37:34 -0400 Subject: Re: bug with multiple mounts of filesystems in 2.6 From: Trond Myklebust To: John S J Anderson Cc: linux-kernel@vger.kernel.org In-Reply-To: <86oem2hgv8.fsf@mendel.genehack.org> References: <86oem2hgv8.fsf@mendel.genehack.org> Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: 8BIT Message-Id: <1090870651.6809.62.camel@lade.trondhjem.org> Mime-Version: 1.0 X-Mailer: Ximian Evolution 1.4.6 Date: Mon, 26 Jul 2004 15:37:31 -0400 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org På må , 26/07/2004 klokka 12:29, skreiv John S J Anderson: > Hi -- > > We're working on migrating to the 2.6 kernel series, and one big > problem has popped up: we have a number of NFS mounts that are > mounted read-only in one location and read-write in a distinct > location (on the same machine). With 2.4 series kernels, this worked > without issue, but with 2.6, it doesn't: it's not possible to mount > the same filesystem twice with different options for each mount; the > two mount points have to share the same mount options. That behaviour is no longer supported as it meant that you would have different superblocks (and hence different out-of-sync caches) between the 2 mountpoint. It is in any case not a behaviour that is supported on any other Linux filesystems. If you want readonly to be an exception, then you will have to move the MS_RDONLY flag from being a superblock option to being a vfsmount option, then propagate that vfsmount information down to all the tests of IS_RDONLY(inode). Not a trivial task, and not one that looms high on my list of priorities... Cheers, Trond