From: Benny Halevy Subject: Re: [pnfs] [PATCH 0/2] fix nfsd stateid encoding Date: Mon, 11 Aug 2008 19:11:40 +0300 Message-ID: <48A064BC.1050302@panasas.com> References: <48A04820.5000409@panasas.com> <20080811155842.GC32193@fieldses.org> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Cc: NFS list , pNFS Mailing List To: "J. Bruce Fields" Return-path: Received: from nf-out-0910.google.com ([64.233.182.190]:10582 "EHLO nf-out-0910.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751513AbYHKQLq (ORCPT ); Mon, 11 Aug 2008 12:11:46 -0400 Received: by nf-out-0910.google.com with SMTP id d3so689767nfc.21 for ; Mon, 11 Aug 2008 09:11:44 -0700 (PDT) In-Reply-To: <20080811155842.GC32193@fieldses.org> Sender: linux-nfs-owner@vger.kernel.org List-ID: On Aug. 11, 2008, 18:58 +0300, "J. Bruce Fields" wrote: > On Mon, Aug 11, 2008 at 05:09:36PM +0300, Benny Halevy wrote: >> Bruce, in a couple locations the nfsd needs to encode the stateid.seqid >> as a uint32_t rather than as opaque. > > Agreed, thanks. > > Though I have a hard time figuring out whether this has any impact in > practice. Presumably the only change on the wire is that we'll get the > endianness of the stateid4.seqid right? But that field is mostly opaque > to the client anyway; 3530 says > > The server is required to increment the seqid field > monotonically at each transition of the stateid. This is > important since the client will inspect the seqid in OPEN > stateids to determine the order of OPEN processing done by the > server. > > but doesn't say why this is important. I'm sure this has been brought > up on the ietf list before, but can't recall whether someone came up > with a justification for the importance of this. > > Anyway, so I figure these should be queued up for the next (2.6.28) > merge window. Thanks! Actually, I think this breaks delegreturn. Since we decode the stateid.si_generation correctly, it will get swabbed in delegreturn on little-endian servers. This will cause nfs4_preprocess_stateid_op/check_stateid_generation as called by nfsd4_delegreturn to fail. And eventually, unhash_delegation wouldn't be called. Hence, I think these patches are appropriate for 2.6.27 and even to older stable releases. Benny > > --b. > >> Patch #1 fixes that for cb_recall. >> Patch #2 fixes the deleg stateid returned by open. >> >> The patches should apply to linux-2.6/master >> commit 796aadeb1b2db9b5d463946766c5bbfd7717158c >> >> Benny > _______________________________________________ > pNFS mailing list > pNFS@linux-nfs.org > http://linux-nfs.org/cgi-bin/mailman/listinfo/pnfs