Re: [PATCH 1/1] nfsd41: renew_client() needs to be called with the client_mutex held

["Labiaga, Ricardo" <ricardo.labiaga@netapp.com>]

On 6/18/09 10:31 AM, "J. Bruce Fields" <bfields@fieldses.org> wrote:

> On Wed, Jun 17, 2009 at 06:50:45PM -0700, Ricardo Labiaga wrote:
>> renew_client() manipulates the client queue for lease renewal.  Need to
>> obtain the client_mutex before manipulating it.
>> 
>> Signed-off-by: Ricardo Labiaga <Ricardo.Labiaga@netapp.com>
>> ---
>>  fs/nfsd/nfs4state.c |    2 ++
>>  1 files changed, 2 insertions(+), 0 deletions(-)
>> 
>> diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
>> index 4cb5d1d..18258d7 100644
>> --- a/fs/nfsd/nfs4state.c
>> +++ b/fs/nfsd/nfs4state.c
>> @@ -1537,7 +1537,9 @@ replay_cache:
>> * Hold a session reference until done processing the compound:
>> * nfsd4_put_session called only if the cstate slot is set.
>> */
>> + nfs4_lock_state();
>> renew_client(session->se_client);
>> + nfs4_unlock_state();
>> nfsd4_get_session(session);
>>  out:
>> spin_unlock(&sessionid_lock);
> 
> We can't take a mutex while handling a spinlock.  (And you should have
> gotten warnings about this--not sure what kernel hacking config options
> you may need turned on for that.)
> 

Ah, OK.  I didn't know that.

> Possible hack: add a spinlock that for now will just cover the client
> lru?

Let me study this some more and see if I can simply drop the sessionid
spinlock before renewing the state.

- ricardo

> 
> --b.