On Tue, Aug 25, 2015 at 07:28:03PM +0200, Ulrich Gemkow wrote:
> Hello Bruce,
>
> On Monday 24 August 2015 22:14:01 J. Bruce Fields wrote:
> > On Mon, Aug 24, 2015 at 02:52:55PM +0200, Ulrich Gemkow wrote:
> > > we have a weired problem with Linux NFSv4.0 Server (Vanilla
> > > Kernel 4.1.6) and a Sun Solaris 10 client (all patches applied):
> > >
> > > When mounting a share on the Solaris client and then rebooting
> > > the client without unmounting the share first, after the reboot
> > > every attempt to mount the share again gives an I/O error on
> > > the client and the mount fails.
> > >
> > > After a long time (serveral hours) the v4 mount suddenly works
> > > again.
> > >
> > > Mounting a share with vers=2 works always even in times when
> > > the v4 mount fails.
> > >
> > > So it seems the Linux NFSv4 server holds a state for the client
> > > which prevents the re-mounting of the share and gives the
> > > I/O-error on the client.
> > >
> > > We use NFSv4 without idmapd.
> > >
> > > Is there any tip how to debug or solve this?
> >
> > Best is probably to get a packet trace. So something like:
> >
> > tcpdump -s0 -iem0 -wtmp.pcap
> >
> > and then try the client mount, then kill the tcpdump after the mount
> > fails, and send us tmp.pcap. (And/or take a look at tmp.pcap yourself
> > with wireshark. The interesting question is what kind of error the
> > server is returning when the client tries the mount after reboot.)
>
> Thank you for your reply. The tcpdump is attached, the relevant
> packets are 49..52. The error seems to be a SERVERFAULT. Can you
> see more from the dump?
>
> Thanks again and best regards
The SERVERFAULT is on SETCLIENTID_CONFIRM.
In nfsd4_setclientid_confirm():
conf = find_confirmed_client(clid, false, nn);
unconf = find_unconfirmed_client(clid, false, nn);
/*
* We try hard to give out unique clientid's, so if we get an
* attempt to confirm the same clientid with a different cred,
* there's a bug somewhere. Let's charitably assume it's our
* bug.
*/
status = nfserr_serverfault;
if (unconf && !same_creds(&unconf->cl_cred, &rqstp->rq_cred))
goto out;
if (conf && !same_creds(&conf->cl_cred, &rqstp->rq_cred))
goto out;
The SETCLIENTID and SETCLIENTID_CONFIRM are done with identical
auth_unix creds.
The clientid that were looking up there was returned from the previous
SETCLIENTID, generated by this logic:
if (conf && same_verf(&conf->cl_verifier, &clverifier))
/* case 1: probable callback update */
copy_clid(new, conf);
else /* case 4 (new client) or cases 2, 3 (client reboot): */
gen_clid(new, nn);
So it should be a brand new clientid, unless the client was reusing the old
verifier.
So perhaps the client is sending the SETCLIENTID with a verifier set to what it
used on the previous boot? That sounds like a client bug. The linux
client uses a timestamp for the verifier, looks like the Solaris client
might too. Is there some reason the clock on this client isn't
advancing on reboot?
--b.
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