Return-Path: Received: from fieldses.org ([173.255.197.46]:50072 "EHLO fieldses.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750975AbdAXTx5 (ORCPT ); Tue, 24 Jan 2017 14:53:57 -0500 Date: Tue, 24 Jan 2017 14:53:50 -0500 From: "J. Bruce Fields" To: Chuck Lever Cc: Linux NFS Mailing List Subject: Re: [PATCH v1] nfs: Don't increment lock sequence ID after NFS4ERR_MOVED Message-ID: <20170124195350.GC20844@fieldses.org> References: <20170122190429.7337.77928.stgit@manet.1015granger.net> <69D3212A-874D-42A2-BE65-F3A01B061A87@oracle.com> <20170123164913.GB9493@fieldses.org> <1F944D3D-A28B-48C5-88CC-39EBD6CB8430@oracle.com> <20170124191515.GA20844@fieldses.org> <677C0AEE-D64A-489E-B7CE-4BFEEABAA6EA@oracle.com> <20170124194140.GB20844@fieldses.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <20170124194140.GB20844@fieldses.org> Sender: linux-nfs-owner@vger.kernel.org List-ID: On Tue, Jan 24, 2017 at 02:41:40PM -0500, J. Bruce Fields wrote: > On Tue, Jan 24, 2017 at 02:31:37PM -0500, Chuck Lever wrote: > > Adding a justification is OK with me, and please replace the > > list of steps with my updated list above. > > > > However, your explanation implies that Solaris is the only server > > that might need this fix. Actually _any_ server that supports > > transparent state migration needs clients to get this fix. Lock > > operations on a file that has moved are not able to update the > > sequence ID on the destination server. > > Are you sure? Couldn't an implementation include a server-to-server > protocol that allowed the source and destination server to share stateid > information? > > But even if that's possible, it may be unnecessarily complicated, so I > agree I shouldn't be claiming it's a Solaris-specific issue (though it > may be worth documenting that's who first hit this). > > --b. > > > This backwards-compatible change is OK because: > > > > - No servers in the wild support migration yet, thus > > NFS4ERR_MOVED is never returned by existing servers I think you mean "transparent state migration" there? A server supporting non-transparent state migration could return NFS4ERR_MOVED on a LOCK operation, but the client won't be able to use that stateid afterwards in that case anyway. > > - Clients that do not support migration should never receive > > NFS4ERR_MOVED on a state-mutating operation I didn't think there was a way for clients to advertise non-support for migration? But such clients could never recover from MOVED anyway, so we're not making things worse for them. --b. > > > > In other words, this change is necessary only for clients that > > support TSM. > > > > Salt to taste. > > > > > > > --b. > > > > > >> > > >> > > >>> --b. > > >>> > > >>>>> > > >>>>> Reported-by: Xuan Qi > > >>>>> Signed-off-by: Chuck Lever > > >>>>> Cc: stable@vger.kernel.org # v3.7+ > > >>>>> --- > > >>>>> include/linux/nfs4.h | 3 ++- > > >>>>> 1 file changed, 2 insertions(+), 1 deletion(-) > > >>>>> > > >>>>> diff --git a/include/linux/nfs4.h b/include/linux/nfs4.h > > >>>>> index bca5363..1b1ca04 100644 > > >>>>> --- a/include/linux/nfs4.h > > >>>>> +++ b/include/linux/nfs4.h > > >>>>> @@ -282,7 +282,7 @@ enum nfsstat4 { > > >>>>> > > >>>>> static inline bool seqid_mutating_err(u32 err) > > >>>>> { > > >>>>> - /* rfc 3530 section 8.1.5: */ > > >>>>> + /* See RFC 7530, section 9.1.7 */ > > >>>>> switch (err) { > > >>>>> case NFS4ERR_STALE_CLIENTID: > > >>>>> case NFS4ERR_STALE_STATEID: > > >>>>> @@ -291,6 +291,7 @@ static inline bool seqid_mutating_err(u32 err) > > >>>>> case NFS4ERR_BADXDR: > > >>>>> case NFS4ERR_RESOURCE: > > >>>>> case NFS4ERR_NOFILEHANDLE: > > >>>>> + case NFS4ERR_MOVED: > > >>>>> return false; > > >>>>> }; > > >>>>> return true; > > >>>>> > > >>>>> -- > > >>>>> To unsubscribe from this list: send the line "unsubscribe linux-nfs" in > > >>>>> the body of a message to majordomo@vger.kernel.org > > >>>>> More majordomo info at http://vger.kernel.org/majordomo-info.html > > >>>> > > >>>> -- > > >>>> Chuck Lever > > >>>> > > >>>> > > >>>> > > >>>> -- > > >>>> To unsubscribe from this list: send the line "unsubscribe linux-nfs" in > > >>>> the body of a message to majordomo@vger.kernel.org > > >>>> More majordomo info at http://vger.kernel.org/majordomo-info.html > > >>> -- > > >>> To unsubscribe from this list: send the line "unsubscribe linux-nfs" in > > >>> the body of a message to majordomo@vger.kernel.org > > >>> More majordomo info at http://vger.kernel.org/majordomo-info.html > > >> > > >> -- > > >> Chuck Lever > > >> > > >> > > > -- > > > To unsubscribe from this list: send the line "unsubscribe linux-nfs" in > > > the body of a message to majordomo@vger.kernel.org > > > More majordomo info at http://vger.kernel.org/majordomo-info.html > > > > -- > > Chuck Lever > > > >