Re: [PATCH v2 40/47] nfsd41: cb_sequence callback

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

On Sat, Mar 28, 2009 at 11:34:41AM +0300, Benny Halevy wrote:
> From: Andy Adamson <andros@netapp.com>
> 
> Implement the cb_sequence callback conforming to draft-ietf-nfsv4-minorversion1
> 
> Signed-off-by: Benny Halevy <bhalevy@panasas.com>
> [Rework the back channel xdr using the shared v4.0 and v4.1 framework.]
> Signed-off-by: Andy Adamson <andros@netapp.com>
> [fixed indentation]
> Signed-off-by: Benny Halevy <bhalevy@panasas.com>
> ---
>  fs/nfsd/nfs4callback.c     |  118 ++++++++++++++++++++++++++++++++++++++++++++
>  include/linux/nfsd/state.h |    7 ++-
>  2 files changed, 124 insertions(+), 1 deletions(-)
> 
> diff --git a/fs/nfsd/nfs4callback.c b/fs/nfsd/nfs4callback.c
> index 6b7ef87..7ada6b1 100644
> --- a/fs/nfsd/nfs4callback.c
> +++ b/fs/nfsd/nfs4callback.c
> @@ -255,6 +255,29 @@ encode_cb_recall(struct xdr_stream *xdr, struct nfs4_cb_recall *cb_rec,
>  	hdr->nops++;
>  }
>  
> +static void
> +encode_cb_sequence(struct xdr_stream *xdr, struct nfsd4_cb_sequence *args,
> +		   struct nfs4_cb_compound_hdr *hdr)
> +{
> +	__be32 *p;
> +
> +	if (hdr->minorversion == 0)
> +		return;
> +
> +	RESERVE_SPACE(1 + NFS4_MAX_SESSIONID_LEN + 20);
> +
> +	WRITE32(OP_CB_SEQUENCE);
> +#ifdef CONFIG_NFSD_V4_1
> +	WRITEMEM(args->cbs_clp->cl_sessionid.data, NFS4_MAX_SESSIONID_LEN);
> +	WRITE32(args->cbs_clp->cl_cb_seq_nr);
> +#endif /* CONFIG_NFSD_V4_1 */

This whole function should be under CONFIG_NFSD_V4_1.

> +	WRITE32(0);		/* slotid, always 0 */
> +	WRITE32(0);		/* highest slotid always 0 */
> +	WRITE32(0);		/* cachethis always 0 */
> +	WRITE32(0); /* FIXME: support referring_call_lists */
> +	hdr->nops++;
> +}
> +
>  static int
>  nfs4_xdr_enc_cb_null(struct rpc_rqst *req, __be32 *p)
>  {
> @@ -319,6 +342,69 @@ decode_cb_op_hdr(struct xdr_stream *xdr, enum nfs_opnum4 expected)
>  	return 0;
>  }
>  
> +/*
> + * Our current back channel implmentation supports a single backchannel
> + * with a single slot.
> + */
> +static int
> +decode_cb_sequence(struct xdr_stream *xdr, struct nfsd4_cb_sequence *res,
> +		   struct rpc_rqst *rqstp)
> +{
> +	struct nfs4_callback *cb =
> +		(struct nfs4_callback *)rqstp->rq_task->tk_client->cl_private;
> +	struct nfs4_sessionid id;
> +	int status;
> +	u32 dummy;
> +	__be32 *p;
> +
> +	if (cb->cb_minorversion == 0)
> +		return 0;
> +
> +	status = decode_cb_op_hdr(xdr, OP_CB_SEQUENCE);
> +	if (status)
> +		return status;
> +
> +	/*
> +	 * If the server returns different values for sessionID, slotID or
> +	 * sequence number, the server is looney tunes.
> +	 */
> +	status = -ESERVERFAULT;
> +
> +	READ_BUF(NFS4_MAX_SESSIONID_LEN + 16);
> +	COPYMEM(id.data, NFS4_MAX_SESSIONID_LEN);
> +#ifdef CONFIG_NFSD_V4_1
> +	if (memcmp(id.data, res->cbs_clp->cl_sessionid.data,
> +		   NFS4_MAX_SESSIONID_LEN)) {
> +		dprintk("%s Invalid session id\n", __func__);
> +		goto out;
> +	}
> +	READ32(dummy);
> +	if (dummy != res->cbs_clp->cl_cb_seq_nr) {
> +		dprintk("%s Invalid sequence number\n", __func__);
> +		goto out;
> +	}
> +#endif /* CONFIG_NFSD_V4_1 */

Ditto.

> +	READ32(dummy); 	/* slotid must be 0 */
> +	if (dummy != 0) {
> +		dprintk("%s Invalid slotid\n", __func__);
> +		goto out;
> +	}
> +	READ32(dummy); 	/* highest slotid must be 0 */
> +	if (dummy != 0) {
> +		dprintk("%s Invalid highest slotid\n", __func__);
> +		goto out;
> +	}
> +	READ32(dummy); 	/* target highest slotid must be 0 */
> +	if (dummy != 0) {
> +		dprintk("%s Invalid target highest slotid\n", __func__);
> +		goto out;
> +	}
> +	status = 0;
> +out:
> +	return status;
> +}
> +
> +
>  static int
>  nfs4_xdr_dec_cb_null(struct rpc_rqst *req, __be32 *p)
>  {
> @@ -503,6 +589,38 @@ nfsd4_probe_callback(struct nfs4_client *clp)
>  	return;
>  }
>  
> +#if defined(CONFIG_NFSD_V4_1)
> +/*
> + * FIXME: cb_sequence should support referring call lists, cachethis, and
> + * multiple slots
> + */
> +static int
> +nfs41_cb_sequence_setup(struct nfs4_client *clp, struct nfsd4_cb_sequence *args)
> +{
> +	u32 *ptr = (u32 *)clp->cl_sessionid.data;
> +
> +	dprintk("%s: %u:%u:%u:%u\n", __func__,
> +		ptr[0], ptr[1], ptr[2], ptr[3]);
> +
> +	mutex_lock(&clp->cl_cb_mutex);

We shouldn't be holding a mutex across a callback.  Why is this needed?

--b.

> +	args->cbs_clp = clp;
> +	clp->cl_cb_seq_nr++;
> +	return 0;
> +}
> +
> +static void
> +nfs41_cb_sequence_done(struct nfs4_client *clp, struct nfsd4_cb_sequence *res)
> +{
> +	u32 *ptr = (u32 *)clp->cl_sessionid.data;
> +
> +	dprintk("%s: %u:%u:%u:%u\n", __func__,
> +		ptr[0], ptr[1], ptr[2], ptr[3]);
> +
> +	/* FIXME: support multiple callback slots */
> +	mutex_unlock(&clp->cl_cb_mutex);
> +}
> +#endif /* CONFIG_NFSD_V4_1 */
> +
>  /*
>   * called with dp->dl_count inc'ed.
>   */
> diff --git a/include/linux/nfsd/state.h b/include/linux/nfsd/state.h
> index f2783d4..0ea8c89 100644
> --- a/include/linux/nfsd/state.h
> +++ b/include/linux/nfsd/state.h
> @@ -61,6 +61,10 @@ typedef struct {
>  #define si_stateownerid   si_opaque.so_stateownerid
>  #define si_fileid         si_opaque.so_fileid
>  
> +struct nfsd4_cb_sequence {
> +	/* args/res */
> +	struct nfs4_client	*cbs_clp;
> +};
>  
>  struct nfs4_cb_recall {
>  	u32			cbr_ident;
> @@ -195,7 +199,8 @@ struct nfs4_client {
>  	struct nfsd4_slot	cl_slot;	/* create_session slot */
>  	u32			cl_exchange_flags;
>  	struct nfs4_sessionid	cl_sessionid;
> -
> +	/* We currently support a single back channel with a single slot */
> +	u32			cl_cb_seq_nr;
>  	struct svc_xprt		*cl_cb_xprt;	/* 4.1 callback transport */
>  	struct mutex		cl_cb_mutex;
>  #endif /* CONFIG_NFSD_V4_1 */
> -- 
> 1.6.2.1
>