Re: [pnfs] [RFC 09/10] nfsd41: cb_sequence callback

Benny Halevy
2009-05-01T08:34:32Z

On May. 01, 2009, 2:52 +0300, Trond Myklebust <trond.myklebust@fys.uio.no> wrote:
> On Fri, 2009-05-01 at 02:06 +0300, Benny Halevy wrote:
>> From: Andy Adamson <andros@netapp.com>
>>
>> Implement the cb_sequence callback conforming to draft-ietf-nfsv4-minorversion1
>>
>> Note: highest slot id and target highest slot id do not have to be 0
>> as was previously implemented. They can be greater than what the
>> nfs server sent if the client supports a larger slot table on the
>> backchannel. At this point we just ignore that.
>>
>> 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>
>> [nfsd41: use nfsd4_cb_sequence for callback minorversion]
>> Signed-off-by: Benny Halevy <bhalevy@panasas.com>
>> [nfsd41: fix verification of CB_SEQUENCE highest slot id[
>> Signed-off-by: Benny Halevy <bhalevy@panasas.com>
>> [nfsd41: Backchannel: Remove old backchannel serialization]
>> [nfsd41: Backchannel: First callback sequence ID should be 1]
>> Signed-off-by: Ricardo Labiaga <Ricardo.Labiaga@netapp.com>
>> Signed-off-by: Benny Halevy <bhalevy@panasas.com>
>> ---
>> fs/nfsd/nfs4callback.c | 72 ++++++++++++++++++++++++++++++++++++++++++++++++
>> fs/nfsd/nfs4state.c | 1 +
>> 2 files changed, 73 insertions(+), 0 deletions(-)
>>
>> diff --git a/fs/nfsd/nfs4callback.c b/fs/nfsd/nfs4callback.c
>> index 2bf2cd4..78f4dd2 100644
>> --- a/fs/nfsd/nfs4callback.c
>> +++ b/fs/nfsd/nfs4callback.c
>> @@ -264,6 +264,27 @@ 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);
>> + WRITEMEM(args->cbs_clp->cl_sessionid.data, NFS4_MAX_SESSIONID_LEN);
>> + WRITE32(args->cbs_clp->cl_cb_seq_nr);
>> + 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)
>> {
>> @@ -325,6 +346,57 @@ 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_sessionid id;
>> + int status;
>> + u32 dummy;
>> + __be32 *p;
>> +
>> + if (res->cbs_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);
>> + 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;
>> + }
>> + READ32(dummy); /* slotid must be 0 */
>> + if (dummy != 0) {
>> + dprintk("%s Invalid slotid\n", __func__);
>> + goto out;
>> + }
>> + READ32(dummy); /* highest slotid */
> ^^^^^^^^^^^^^
>
>> + READ32(dummy); /* target highest slotid */
> ^^^^^^^^^^^^^^
>
> Why do you need those?

Good catch :)
Since READ_BUF (xdr_inline_decode) indeed takes care of
adjusting the xdr_stream pointer we can take them out.
A FIXME comment about the need to process these channel
attributes would be clearer.

Benny

>
>> + status = 0;
>> +out:
>> + return status;
>> +}
>> +
>> +
>> static int
>> nfs4_xdr_dec_cb_null(struct rpc_rqst *req, __be32 *p)
>> {
>> diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
>> index d7b4028..6f3cf47 100644
>> --- a/fs/nfsd/nfs4state.c
>> +++ b/fs/nfsd/nfs4state.c
>> @@ -1400,6 +1400,7 @@ nfsd4_create_session(struct svc_rqst *rqstp,
>> svc_xprt_get(unconf->cl_cb_xprt);
>> unconf->cl_callback.cb_minorversion =
>> cstate->minorversion;
>> + unconf->cl_cb_seq_nr = 1;
>> unconf->cl_callback.cb_prog = cr_ses->callback_prog;
>> nfsd4_probe_callback(unconf);
>> }
>> --
>> 1.6.2.1
>>
>> _______________________________________________
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>> pNFS@linux-nfs.org
>> http://linux-nfs.org/cgi-bin/mailman/listinfo/pnfs
>
>