nfs41: back channel drc minimal implementation
For now the back channel ca_maxresponsesize_cached is 0 and there is no
backchannel DRC. Return NFS4ERR_REP_TOO_BIG_TO_CACHE when a cb_sequence
cachethis is true. When it is false, return NFS4ERR_RETRY_UNCACHED_REP as the
next operation error.
Remember the replay error accross compound operation processing.
Signed-off-by: Andy Adamson <andros@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
diff --git a/fs/nfs/callback_proc.c b/fs/nfs/callback_proc.c
index 3d7edd6..4062f76 100644
--- a/fs/nfs/callback_proc.c
+++ b/fs/nfs/callback_proc.c
@@ -143,9 +143,8 @@
* Return success if the sequenceID is one more than what we last saw on
* this slot, accounting for wraparound. Increments the slot's sequence.
*
- * We don't yet implement a duplicate request cache, so at this time
- * we will log replays, and process them as if we had not seen them before,
- * but we don't bump the sequence in the slot. Not too worried about it,
+ * We don't yet implement a duplicate request cache, instead we set the
+ * back channel ca_maxresponsesize_cached to zero. This is OK for now
* since we only currently implement idempotent callbacks anyway.
*
* We have a single slot backchannel at this time, so we don't bother
@@ -174,9 +173,15 @@
/* Replay */
if (args->csa_sequenceid == slot->seq_nr) {
- dprintk("%s seqid %d is a replay - no DRC available\n",
+ dprintk("%s seqid %d is a replay\n",
__func__, args->csa_sequenceid);
- return htonl(NFS4_OK);
+ /* Signal process_op to set this error on next op */
+ if (args->csa_cachethis == 0)
+ return htonl(NFS4ERR_RETRY_UNCACHED_REP);
+
+ /* The ca_maxresponsesize_cached is 0 with no DRC */
+ else if (args->csa_cachethis == 1)
+ return htonl(NFS4ERR_REP_TOO_BIG_TO_CACHE);
}
/* Wraparound */
@@ -319,9 +324,13 @@
kfree(args->csa_rclists[i].rcl_refcalls);
kfree(args->csa_rclists);
- dprintk("%s: exit with status = %d\n", __func__, ntohl(status));
- res->csr_status = status;
- return res->csr_status;
+ if (status == htonl(NFS4ERR_RETRY_UNCACHED_REP))
+ res->csr_status = 0;
+ else
+ res->csr_status = status;
+ dprintk("%s: exit with status = %d res->csr_status %d\n", __func__,
+ ntohl(status), ntohl(res->csr_status));
+ return status;
}
unsigned nfs4_callback_recallany(struct cb_recallanyargs *args, void *dummy)
diff --git a/fs/nfs/callback_xdr.c b/fs/nfs/callback_xdr.c
index a6f2ded..08b430d 100644
--- a/fs/nfs/callback_xdr.c
+++ b/fs/nfs/callback_xdr.c
@@ -605,7 +605,7 @@
static __be32 process_op(uint32_t minorversion, int nop,
struct svc_rqst *rqstp,
struct xdr_stream *xdr_in, void *argp,
- struct xdr_stream *xdr_out, void *resp)
+ struct xdr_stream *xdr_out, void *resp, int* drc_status)
{
struct callback_op *op = &callback_ops[0];
unsigned int op_nr;
@@ -628,6 +628,11 @@
if (status)
goto encode_hdr;
+ if (*drc_status) {
+ status = *drc_status;
+ goto encode_hdr;
+ }
+
maxlen = xdr_out->end - xdr_out->p;
if (maxlen > 0 && maxlen < PAGE_SIZE) {
status = op->decode_args(rqstp, xdr_in, argp);
@@ -636,6 +641,12 @@
} else
status = htonl(NFS4ERR_RESOURCE);
+ /* Only set by OP_CB_SEQUENCE processing */
+ if (status == htonl(NFS4ERR_RETRY_UNCACHED_REP)) {
+ *drc_status = status;
+ status = 0;
+ }
+
encode_hdr:
res = encode_op_hdr(xdr_out, op_nr, status);
if (unlikely(res))
@@ -655,7 +666,7 @@
struct cb_compound_hdr_res hdr_res = { NULL };
struct xdr_stream xdr_in, xdr_out;
__be32 *p;
- __be32 status;
+ __be32 status, drc_status = 0;
unsigned int nops = 0;
dprintk("%s: start\n", __func__);
@@ -675,8 +686,8 @@
return rpc_system_err;
while (status == 0 && nops != hdr_arg.nops) {
- status = process_op(hdr_arg.minorversion, nops,
- rqstp, &xdr_in, argp, &xdr_out, resp);
+ status = process_op(hdr_arg.minorversion, nops, rqstp,
+ &xdr_in, argp, &xdr_out, resp, &drc_status);
nops++;
}