From mboxrd@z Thu Jan 1 00:00:00 1970 From: Trond Myklebust Subject: Re: nfs + Reiser4 Date: Wed, 07 Apr 2010 17:09:27 -0400 Message-ID: <1270674567.3177.2.camel@localhost.localdomain> References: <20100407173438.GA25614@fieldses.org> <4BBCD271.5040100@oracle.com> <20100407185157.GF26072@fieldses.org> <4BBCD618.50301@oracle.com> <20100407192025.GH26072@fieldses.org> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Cc: Chuck Lever , linux-nfs@vger.kernel.org, gg-B3jsHfKwJfLR7s880joybQ@public.gmane.org To: "J. Bruce Fields" Return-path: Received: from mail-out2.uio.no ([129.240.10.58]:48164 "EHLO mail-out2.uio.no" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750810Ab0DGVJf (ORCPT ); Wed, 7 Apr 2010 17:09:35 -0400 In-Reply-To: <20100407192025.GH26072@fieldses.org> Sender: linux-nfs-owner@vger.kernel.org List-ID: On Wed, 2010-04-07 at 15:20 -0400, J. Bruce Fields wrote: > On Wed, Apr 07, 2010 at 02:59:36PM -0400, Chuck Lever wrote: > > On 04/07/2010 02:51 PM, J. Bruce Fields wrote: > >> On Wed, Apr 07, 2010 at 02:44:01PM -0400, Chuck Lever wrote: > >>> On 04/07/2010 01:34 PM, J. Bruce Fields wrote: > >>>> On Tue, Apr 06, 2010 at 07:52:21PM +0200, gg-B3jsHfKwJfLR7s880joybQ@public.gmane.org wrote: > >>>>> I am having serious headaches using nfs between a reiser4 server and arm > >>>>> client. > >>>>> Both on 2.6.29 vintage kernels. > >>>>> > >>>>> Files are constantly getting out of sync. > >>>>> > >>>>> Example : > >>>>> > >>>>> boot ARM via nfs > >>>>> edit lighttpd.conf on ARM > >>>>> check edit is visible on server. OK > >>>>> > >>>>> reboot ARM > >>>>> check file : reverted to an earlier state. > >>>>> check server: edited version still showing. > >>>> > >>>> So, on a freshly booted NFS client, you're opening and reading a file > >>>> and seeing file data that isn't even on the NFS server any more? > >>>> > >>>> That's beyond bizarre. Do you have a reliable way to reproduce the > >>>> problem? > >>> > >>> Could be XID replay. > >> > >> I'm not following you. You're thinking of a read request after the > >> reboot that unluckily reuses an old XID and gets stale data from the > >> servers reply cache? Or something else? > > > > Nothing unlucky about it. Just after a boot, if the client > > implementation isn't careful about choosing an initial XID, (eg it > > always starts with a psuedorandom number but uses the same seed every > > time), it will hit the server's replay cache. > > Hm, OK. > > > This can be quite reproducible for NFSROOT and a quiescent server. > > The Linux server doesn't cache READ results as far as I can tell. > > --b. Is he perhaps using the Debian unfsd or some other user space nfs server? Cheers Trond