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 <xuan.qi@xxxxxxxxxx>
> > >>>>> Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx>
> > >>>>> Cc: stable@xxxxxxxxxxxxxxx # 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@xxxxxxxxxxxxxxx
> > >>>>> 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@xxxxxxxxxxxxxxx
> > >>>> 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@xxxxxxxxxxxxxxx
> > >>> 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@xxxxxxxxxxxxxxx
> > > More majordomo info at http://vger.kernel.org/majordomo-info.html
> >
> > --
> > Chuck Lever
> >
> >
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