From mboxrd@z Thu Jan 1 00:00:00 1970 From: Artem Bityutskiy Subject: NFS and non-blkdev-backed FS? Date: Fri, 15 Aug 2008 11:55:59 +0300 Message-ID: <48A5449F.7050205@nokia.com> Reply-To: Artem.Bityutskiy@nokia.com Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: QUOTED-PRINTABLE To: linux-fsdevel@vger.kernel.org Return-path: Received: from smtp.nokia.com ([192.100.122.230]:24216 "EHLO mgw-mx03.nokia.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753011AbYHOI4X (ORCPT ); Fri, 15 Aug 2008 04:56:23 -0400 Received: from vaebh105.NOE.Nokia.com (vaebh105.europe.nokia.com [10.160.244.31]) by mgw-mx03.nokia.com (Switch-3.2.6/Switch-3.2.6) with ESMTP id m7F8uIOs017573 for ; Fri, 15 Aug 2008 11:56:20 +0300 Sender: linux-fsdevel-owner@vger.kernel.org List-ID: When I NFS-export UBIFS, I see the following warning: exportfs: Warning: /mnt/ubifs requires fsid=3D for NFS export And the client won't mount UBIFS: mount.nfs: access denied by server while mounting gollum:/mnt/ubifs The problem is solved by adding 'fsid=3D5' to /etc/exports. And BTW, exactly the same happens to JFFS2. This looks strange to me, probably because I misunderstand something. AFAIU, NFS uses major/minor numbers of block device to create =46SID and uses it as part of file handle. And the idea behind this is that if the server rebooted unexpectedly, and then exported a _different_ file-system to the same path, the client would notice this because the FSID part of file handle would change. Well, I do not see how it solves the problem if the hard drive has been changed, though. Since UBIFS (and JFFS2) does not work on top of block devices, NFS cannot compose FSID from major/minor numbers and exportfs yells. But I do not like the idea of adding explicit fsid=3D5 to /etc/exports, because it does not seem to solve the above problem, surely? UBIFS (as e.g. XFS) has a 16-byte UUID in superblock which is supposed to uniquely identify the file-system. I'd like to use this UUID as NFS FSID instead, however, I failed to find how to do this. Any hints how could I do this? Thanks. --=20 Best Regards, Artem Bityutskiy (=D0=90=D1=80=D1=82=D1=91=D0=BC =D0=91=D0=B8=D1=82=D1=8E= =D1=86=D0=BA=D0=B8=D0=B9) -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel= " in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html