nfsd41: Backchannel: cb_sequence callback

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>
Signed-off-by: Ricardo Labiaga <Ricardo.Labiaga@netapp.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>
[nfsd41: decode_cb_sequence does not need to actually decode ignored fields]
Signed-off-by: Benny Halevy <bhalevy@panasas.com>
Signed-off-by: Ricardo Labiaga <Ricardo.Labiaga@netapp.com>
Signed-off-by: Benny Halevy <bhalevy@panasas.com>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>

1 files changed, 72 insertions, 0 deletions

diff --git a/fs/nfsd/nfs4callback.c b/fs/nfsd/nfs4callback.c
index 25a09069e458..d37707d26dee 100644
--- a/fs/nfsd/nfs4callback.c
+++ b/fs/nfsd/nfs4callback.c
@@ -256,6 +256,27 @@ encode_cb_recall(struct xdr_stream *xdr, struct nfs4_delegation *dp,
         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)
 {
@@ -317,6 +338,57 @@ 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);
+        memcpy(id.data, p, NFS4_MAX_SESSIONID_LEN);
+        p += XDR_QUADLEN(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;
+        }
+        /* FIXME: process highest slotid and target highest slotid */
+        status = 0;
+out:
+        return status;
+}
+
+
 static int
 nfs4_xdr_dec_cb_null(struct rpc_rqst *req, __be32 *p)
 {