Linux NFSv4 clients: bad sequence-id errors.

[Ruben]

Hi List,


I'm experiencing a strange issue on a machine providing a couple of
nfsv4 exports. A Linux client that generates a lot of traffic to and
from the nfs server sometimes starts throwing "bad sequence-id errors":

Feb 27 10:39:42 localhost kernel: [12481477.608103] NFS: v4 server
returned a bad sequence-id error on an unconfirmed sequence 80f7d0d0!


They typically occur after a couple of months of uptime on the nfsd
machine. Every couple of seconds they are thrown by the client. The
situation is "remedied" by restarting the nfsd on the server. Although
functionality on the specific client does not appear to be affected
(much?), its a bit disturbing. I've done some digging and found :

https://lists.freebsd.org/pipermail/freebsd-fs/2015-July/021707.html

and the patch attached by Rick (  nfsv41exch.patch :
http://lists.freebsd.org/pipermail/freebsd-fs/attachments/20150729/586f776a/attachment.bin
) .

Since the issue started manifesting itself I have restarted the nfs
daemon (grabbed a pcap and the corresponding error lines mentioning the
sequences prior to doing that in case anyone is interested).


The nfs server runs FreeBSD 11.1 :

freebsd-version -uk
11.1-RELEASE-p1
11.1-RELEASE-p1

but I have seen it on 10.2 and 11.0 as well. The linux client is (/has
been) running a version of Debian.

The export lines in /etc/exports :

V4: / -network=192.168.9.0 -mask=255.255.255.0

/data/Sabnzb2015 -maproot=root: -alldirs -network=192.168.9.0
-mask=255.255.255.0

Uptime:

8:27PM  up 196 days, 22:10, 1 users, load averages: 0.21, 0.17, 0.17

Traffice since uptime (guessing NFS / non-NFS ratio of 3 to 1)

          lagg0  in    400.901 KB/s        400.901 KB/s           10.425 TB
                 out    32.781 KB/s         32.781 KB/s           14.132 TB


I'm wondering: can the 2015 patch provided by Rick still be "safely"
applied or has the nfs code changed too much since then? I've witnessed
this issue a couple of times now and would very much like to test the
patch provided.


Kind regards,


Ruben