Re: NFSv4 console messages (locks lost etc.)

Lars Eggert wrote:
> Hi,
> 
> on a -CURRENT client, I get quite a number of console messages under
> heavy NFSv4 load, such as:
> 
> nfsv4 expired locks lost
Means the lease expired on the NFSv4 server somehow. Lease
expiry is "bad news" and there is no way to recover locks
lost because of it.
> nfscl: never fnd open
Usually, opens can be recovered after a lease expiry, but it
might be broken. Since lease expiry should never happen during
normal operation (see below), it doesn't get a lot of testing.

> nfscl: never fnd open
> nfscl: never fnd open
> nfsv4 expired locks lost
> nfscl: never fnd open
> nfscl: never fnd open
> nfsv4 expired locks lost
> nfsv4 expired locks lost
> nfsv4 expired locks lost
> nfsv4 expired locks lost
> nfsv4 expired locks lost
> nfscl: never fnd open
> 
> Can I ignore them? Can I turn them off?
> 
Well, these should never happen during normal, correct operation. The
"nfsv4 expired locks lost" implies lease expiry. This should only happen
when the client is network partitioned from the server for more than
a lease duration (chosen by the server, but typically about 1minute).
The client does a Renew Op every 1/2 lease durations to avoid this. Also,
any state related operation (open/lock/locku/close/etc) is supposed to
renew the lease implicitly.

If you are getting network partitions happening, then you really need
to fix the network.

If not, then if you watch network traffic with something like wireshark
and see Renew Ops happening at regular intervals, then I can only suggest
that the server is somehow broken for NFSv4. You should also look for
NFS4ERR_EXPIRED error replies to operations related to state (open/lock/locku/close).
That is the server reply which indicates the lease expiry. If the server is
never returning this, I have no idea how the client would generate the above
messages, but it does indicate a client NFSv4 bug if that is the case.

Switching all mounts to NFSv3 will get rid of the above, although it is
not exactly a fix;-)

rick

> Thanks,
> Lars
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