Hello everyone,I am posting to this list as suggested by Neil F Brown in this OpenSUSE bugzilla: https://bugzilla.novell.com/show_bug.cgi?id=909634
We are mounting user homes and other shares using 'sec=krb' and NFSv4. With kernel 3.16.7+ (includes latest NFS patches, please see BZ link for details) we are seeing 100% CPU core usage by a kernel process on some machine connected to a 'NetApp FAS 3140 with ONTAP 8.1.4P1 7-mode' NFSv3/4 Server. It looks like the problem is triggered when the NFS server is unavailable for a short period of time or was rebooted.
Neil F Brown has come to the following conclusion so far: ------------- QUOTE -------------What I see happening here is that a WRITE or LOCK request gets NFS4ERR_STALE_STATEID, and then the client sends a "RENEW" request.
If the stateid is really stale, that should fail, but it doesn't. So the client assumes everything is OK and keeps sending requests .... which fail with NFS4ERR_STALE_STATEID.
STALE_STATEID means:
A stateid generated by an earlier server instance was used.
which means that the server must have restarted since that stateid was
issued.
So there seem to be two possible explanations:1/ The server is lying. The stateid isn't really 'stale'. Maybe it is 'bad'. 2/ The client has previously handled a STALE_STATEID error and created a new "client" handle, but hasn't refreshed all of the stateids that it was holding. So it is trying to use old stateid even though it has established a new client.
The client code looks OK, though it is sufficiently complex that I cannot be certain. There are no patches in more recent versions.
------------- END ------------- We have some RPC/NFS debug logs available here: https://bugzilla.novell.com/attachment.cgi?id=631962 And a wireshark trace here: https://bugzilla.novell.com/attachment.cgi?id=632104 What I cannot do:- Trigger or reproduce the problem reliably. It comes up every once in a while. Around 2-3 times a month on a handful of ~50 machines. - Provide logs from with the latest kernel (because I cannot trigger the problem by any means. Updating all ~50 machines is not an option)
What I can do:- Provide logs from or possibly even access to the machine in the 'broken' state for the next couple of days. I will have to reboot it at some time to take the load of the NFS server.
I would be grateful for any help or comments. -J Brauchle
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