Re: [pnfs] [PATCH v2 21/47] nfsd41: nfsd DRC logic

["William A. (Andy) Adamson" <androsadamson@gmail.com>]

On Tue, Mar 31, 2009 at 3:30 PM, J. Bruce Fields <bfields@fieldses.org> wrote:
> On Sat, Mar 28, 2009 at 11:32:44AM +0300, Benny Halevy wrote:
>> From: Andy Adamson <andros@netapp.com>
>>
>> Replay a request in nfsd4_sequence.
>> Add a minorversion to struct nfsd4_compound_state.
>>
>> Pass the current slot to nfs4svc_encode_compound res via struct
>> nfsd4_compoundres to set an NFSv4.1 DRC entry.
>>
>> Signed-off-by: Andy Adamson<andros@netapp.com>
>> Signed-off-by: Benny Halevy <bhalevy@panasas.com>
>> [nfsd41: use bool inuse for slot state]
>> Signed-off-by: Benny Halevy <bhalevy@panasas.com>
>> ---
>>  fs/nfsd/nfs4proc.c        |    7 +++++++
>>  fs/nfsd/nfs4state.c       |    6 ++++++
>>  fs/nfsd/nfs4xdr.c         |   13 +++++++++++++
>>  include/linux/nfsd/xdr4.h |    1 +
>>  4 files changed, 27 insertions(+), 0 deletions(-)
>>
>> diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c
>> index e703ac2..bdbeb87 100644
>> --- a/fs/nfsd/nfs4proc.c
>> +++ b/fs/nfsd/nfs4proc.c
>> @@ -920,6 +920,12 @@ nfsd4_proc_compound(struct svc_rqst *rqstp,
>>                       BUG_ON(op->status == nfs_ok);
>>
>>  encode_op:
>> +             /* Only from SEQUENCE or CREATE_SESSION */
>> +             if (resp->cstate.status == nfserr_replay_cache) {
>> +                     dprintk("%s NFS4.1 replay from cache\n", __func__);
>> +                     status = op->status;
>> +                     goto out;
>> +             }
>>               if (op->status == nfserr_replay_me) {
>>                       op->replay = &cstate->replay_owner->so_replay;
>>                       nfsd4_encode_replay(resp, op);
>> @@ -948,6 +954,7 @@ encode_op:
>>               status = nfserr_jukebox;
>>       }
>>
>> +     resp->cstate.status = status;
>>       fh_put(&resp->cstate.current_fh);
>>       fh_put(&resp->cstate.save_fh);
>>       BUG_ON(resp->cstate.replay_owner);
>> diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
>> index f0ce639..07c869d 100644
>> --- a/fs/nfsd/nfs4state.c
>> +++ b/fs/nfsd/nfs4state.c
>> @@ -997,6 +997,8 @@ nfsd4_replay_cache_entry(struct nfsd4_compoundres *resp)
>>       }
>>
>>       resp->rqstp->rq_resused = entry->ce_resused;
>> +     resp->opcnt = entry->ce_opcnt;
>> +     resp->cstate.iovlen = entry->ce_datav.iov_len + entry->ce_rpchdrlen;
>>       status = entry->ce_status;
>>
>>       return status;
>> @@ -1217,6 +1219,10 @@ nfsd4_sequence(struct svc_rqst *rqstp,
>>       status = check_slot_seqid(seq->seqid, slot);
>>       if (status == nfserr_replay_cache) {
>>               cstate->slot = slot;
>> +             /* Return the cached reply status and set cstate->status
>> +              * for nfsd4_svc_encode_compoundres processing*/
>> +             status = nfsd4_replay_cache_entry(resp);
>> +             cstate->status = nfserr_replay_cache;
>>               goto replay_cache;
>>       }
>>       if (status)
>> diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
>> index c6b490e..57afb33 100644
>> --- a/fs/nfsd/nfs4xdr.c
>> +++ b/fs/nfsd/nfs4xdr.c
>> @@ -3059,6 +3059,19 @@ nfs4svc_encode_compoundres(struct svc_rqst *rqstp, __be32 *p, struct nfsd4_compo
>>               iov = &rqstp->rq_res.head[0];
>>       iov->iov_len = ((char*)resp->p) - (char*)iov->iov_base;
>>       BUG_ON(iov->iov_len > PAGE_SIZE);
>> +#ifdef CONFIG_NFSD_V4_1
>> +     if (resp->cstate.slot != NULL) {
>> +             if (resp->cstate.status == nfserr_replay_cache) {
>> +                     iov->iov_len = resp->cstate.iovlen;
>> +             } else {
>> +                     nfsd4_set_cache_entry(resp);
>> +                     dprintk("%s: SET SLOT STATE TO AVAILABLE\n", __func__);
>> +                     resp->cstate.slot->sl_inuse = 0;
>> +             }
>> +             if (resp->cstate.slot->sl_session)
>
> There's no way that sl_session could ever be NULL, so this check is
> unneeded.

There should have been a comment.
CREATE_SESSION sets cstate->slot using the nfs4_client->cl_slot, a
single slot which it uses for the CREATE_SESSION replay cache. It does
not have a session.


>
> While we're at it: let's just eliminate the sl_session pointer from the
> slot.  I think all that would be needed would be a pointer to the
> session from the cstate, in addition to the pointer to the slot.

OK.

>
> --b.
>
>> +                     nfsd4_put_session(resp->cstate.slot->sl_session);
>> +     }
>> +#endif /* CONFIG_NFSD_V4_1 */
>>       return 1;
>>  }
>>
>> diff --git a/include/linux/nfsd/xdr4.h b/include/linux/nfsd/xdr4.h
>> index cde8947..5c0d376 100644
>> --- a/include/linux/nfsd/xdr4.h
>> +++ b/include/linux/nfsd/xdr4.h
>> @@ -51,6 +51,7 @@ struct nfsd4_compound_state {
>>       /* For sessions DRC */
>>       struct nfsd4_slot       *slot;
>>       __be32                  *statp;
>> +     size_t                  iovlen;
>>       u32                     status;
>>  };
>>
>> --
>> 1.6.2.1
>>
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