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

["J. Bruce Fields" <bfields@fieldses.org>]

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.

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.

--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
>