Re: [PATCH 2/2] nfsv41: handle current stateid on open and close

[Benny Halevy <bhalevy@tonian.com>]

On 2011-12-06 15:40, J. Bruce Fields wrote:
> On Tue, Dec 06, 2011 at 02:31:14PM +0100, Tigran Mkrtchyan wrote:
>> On Tue, Dec 6, 2011 at 12:26 PM, Benny Halevy <bhalevy@tonian.com> wrote:
>>> On 2011-12-06 04:08, J. Bruce Fields wrote:
>>>> On Sun, Dec 04, 2011 at 02:42:11PM +0200, Benny Halevy wrote:
>>>>> On 2011-12-04 14:03, tigran.mkrtchyan@desy.de wrote:
>>>>>> From: Tigran Mkrtchyan <tigran.mkrtchyan@desy.de>
>>>>>>
>>>>>>
>>>>>> Signed-off-by: Tigran Mkrtchyan <tigran.mkrtchyan@desy.de>
>>>>>> ---
>>>>>>  fs/nfsd/nfs4proc.c  |    6 ++++++
>>>>>>  fs/nfsd/nfs4state.c |   26 ++++++++++++++++++++------
>>>>>>  2 files changed, 26 insertions(+), 6 deletions(-)
>>>>>>
>>>>>> diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c
>>>>>> index fa38336..535aed2 100644
>>>>>> --- a/fs/nfsd/nfs4proc.c
>>>>>> +++ b/fs/nfsd/nfs4proc.c
>>>>>> @@ -400,6 +400,12 @@ nfsd4_open(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
>>>>>>      */
>>>>>>     status = nfsd4_process_open2(rqstp, &cstate->current_fh, open);
>>>>>>     WARN_ON(status && open->op_created);
>>>>>> +
>>>>>> +   if(status)
>>>>>> +           goto out;
>>>>>> +
>>>>>> +   /* set current state id */
>>>>>> +   memcpy(&cstate->current_stateid, &open->op_stateid, sizeof(stateid_t));
>>>>
>>>> That comment is a bit redundant.
>>>>
>>>>> Since this should be done for all stateid-returning operations
>>>>> I think that a cleaner approach could be to mark those as such in
>>>>> nfsd4_ops by providing a per-op function to return the operation's
>>>>> stateid.  You can then call this method from nfsd4_proc_compound()
>>>>> after the call to nfsd4_encode_operation() and when status == 0.
>>>>
>>>> So the choice is between
>>>>
>>>> +       memcpy(&cstate->current_stateid, &open->op_stateid,
>>>> sizeof(stateid_t));
>>>>
>>>> and
>>>>
>>>> +       static void get_open_stateid(stateid_t *s)
>>>> +       {
>>>> +               memcpy(s, open->op_stateid);
>>>> +       }
>>>> +
>>>> +       [OP_OPEN] = {
>>>> +               ...
>>>> +               .op_get_stateid = get_open_stateid,
>>>> +               ...
>>>> +       }
>>>>
>>>> ?
>>>>
>>>> I'm not so sure.
>>>
>>> The point is to copy the result stateid into the current_stateid
>>> in a centralized place: nfsd4_proc_compound() and do that for all
>>> stateid-modifying operations.
>>
>> Sounds good, nevertheless all operations call differently resulting
>> stateid which make it's not possible to use a unified schema.

That was the point of introducing a per-op method to get the value.

> 
> Could we just remove all (or most) of those different fields and replace
> them by cstate->current_stateid?

Hmm, that will require changing the corresponding xdr result encoding
routines to use the new field and all other use sites, but I don't think
of a good reason why this won't work.

Benny

> 
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