On Thu, Apr 02, 2009 at 11:47:24AM +0300, Benny Halevy wrote:
> On Apr. 01, 2009, 7:39 +0300, "J. Bruce Fields" <bfields@xxxxxxxxxxxx> wrote:
> > On Sat, Mar 28, 2009 at 11:34:41AM +0300, Benny Halevy wrote:
> >> From: Andy Adamson <andros@xxxxxxxxxx>
> >>
> >> Implement the cb_sequence callback conforming to draft-ietf-nfsv4-minorversion1
> >>
> >> Signed-off-by: Benny Halevy <bhalevy@xxxxxxxxxxx>
> >> [Rework the back channel xdr using the shared v4.0 and v4.1 framework.]
> >> Signed-off-by: Andy Adamson <andros@xxxxxxxxxx>
> >> [fixed indentation]
> >> Signed-off-by: Benny Halevy <bhalevy@xxxxxxxxxxx>
> >> ---
> >> 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?
>
> Just a simple way to limit concurrency to 1 and not deal with
> multiple slots on the callback path.
OK. We should work out some sort of asynchronous equivalent. How is
the client side currently waiting on slots?
--b.
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