Re: [PATCH v2] nfsd: nfsd4_cb_sequence_done() for processing more cb errors

[Kinglong Mee <kinglongmee@gmail.com>]

On 6/24/2015 5:34 AM, J. Bruce Fields wrote:
> On Wed, Jun 17, 2015 at 09:57:34PM +0800, Kinglong Mee wrote:
>> When testing pnfs layout, nfsd got error NFS4ERR_SEQ_MISORDERED.
>> It is caused by nfs return NFS4ERR_DELAY before validate_seqid(),
>> don't update the sequnce id, but nfsd updates the sequnce id !!!
>>
>> According to RFC5661 20.9.3,
>> " If CB_SEQUENCE returns an error, then the state of the slot
>> (sequence ID, cached reply) MUST NOT change."
>>
>> This patch introduce a new helper nfsd4_cb_sequence_done() for
>> processing more callback errors as client.
>>
>> v2, 
>> thanks Christoph's advice of adding a helper process errors as client
> 
> Thanks, could you rebase this on top of my for-4.2 branch?  (I already
> took your earlier patch.)  Also:

Got it.

> 
>> Signed-off-by: Kinglong Mee <kinglongmee@gmail.com>
>> ---
>>  fs/nfsd/nfs4callback.c | 122 +++++++++++++++++++++++++++++++++++++------------
>>  fs/nfsd/state.h        |   1 +
>>  2 files changed, 93 insertions(+), 30 deletions(-)
>>
>> diff --git a/fs/nfsd/nfs4callback.c b/fs/nfsd/nfs4callback.c
>> index ce8d3f2..6fce478 100644
>> --- a/fs/nfsd/nfs4callback.c
>> +++ b/fs/nfsd/nfs4callback.c
> ...
>> @@ -874,6 +874,11 @@ static void nfsd4_cb_prepare(struct rpc_task *task, void *calldata)
>>  	struct nfs4_client *clp = cb->cb_clp;
>>  	u32 minorversion = clp->cl_minorversion;
>>  
>> +	/*
>> +	 * cb_seq_status is only set in decode_cb_sequence4res,
>> +	 * and so will remain 1 if an rpc level failure occurs.
>> +	 */
>> +	cb->cb_seq_status = 1;
> 
> Isn't that a valid error code?  OK, I guess NFS4ERR_PERM isn't a legal
> SEQUENCE return.  Still, -1 might make this a bit more obvious.

No, error code is a negative number, 1 is safe.
Also, it is copied from client's error process in nfs41_sequence_done.

thanks,
Kinglong Mee