If a callback is retried at nfsd4_cb_recall_done() due to
some error, the returned rpc reply crashes here:
@@ -514,6 +514,7 @@ decode_cb_sequence(struct xdr_stream *xdr, struct nfsd4_cb_sequence *res,
u32 dummy;
__be32 *p;
+ BUG_ON(!res);
if (res->cbs_minorversion == 0)
return 0;
[BUG_ON added for demonstration]
This is because the nfsd4_cb_done_sequence() has NULLed out
the task->tk_msg.rpc_resp pointer.
Also eventually the rpc would use the new slot without making
sure it is free by calling nfsd41_cb_setup_sequence().
This problem was introduced by a 4.1 protocol addition patch:
[0421b5c5] nfsd41: Backchannel: Implement cb_recall over NFSv4.1
Which was overlooking the possibility of an RPC callback retries.
For not-4.1 case redoing the _prepare is harmless.
Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
c18c821fd4