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

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

On Wed, Apr 01, 2009 at 11:43:41AM +0300, Benny Halevy wrote:
> On Apr. 01, 2009, 7:39 +0300, "J. Bruce Fields" <bfields@fieldses.org> wrote:
> > 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.
> 
> Right.  I wonder how it got to this state.
> Will fix.

Thanks.  I'm more curious about the mutex question.

But I'm inclined to defer the callback changes to 2.6.31, so that's not
urgent.

--b.

> 
> Benny
> 
> > 
> >> +	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
> >>