Re: BUG: cannot acquire lock twice with NFSv4

[Arnaud Giersch <arnaud.giersch-T9cNH8bv7N6Vy8wrSkPSsihWMY4UYrEW@public.gmane.org>]

Vendredi 09 avril 2010, vers 15:05:14 (+0200), j'ai =C3=A9crit=C2=A0:

>   1. opens a first file, and acquires read lock on it ;
>   2. opens a second file, and acquires read lock on it ;
>   3. releases locks, and closes files.
>
> Both opened files are of course on the NFS mount.  On the first run, =
all
> seems to be fine.  On the second (and subsequent) runs, the lock is
> refused at step 2 with errno=3D37 (ENOLCK, No locks available).

I noticed that things appear to work as expected if commit
8e469ebd6dc32cbaf620e134d79f740bf0ebab79 (NFSv4: Don't allow posix
locking against servers that don't support it) is reverted.

=46rom what I can see, the client is granted a read delegation for the
second file.  On the second run, the client fetches some cached state
for this file.

On this second run, state->flags (as in _nfs4_do_open, or in
nfs4_proc_lock) only contains NFS_DELEGATED_STATE, while on the first
run, it also contained NFS_O_RDONLY_STATE and NFS_STATE_POSIX_LOCKS.

Then, I do not fully understand the code, and I am not able to suggest
any satisfying patch to correct the problem.

Regards,

        Arnaud Giersch