Previously the failing operation would allocate an mbuf and construct an
error reply, but because the function did not return 0, the NFS server
assumed it had failed to generate a reply and would leak the reply mbuf as
well as not sending the reply to the NFS client.
PR: kern/140853
Submitted by: Ted Faber faber at isi edu (remove)
Reviewed by: rmacklem (remove)
MFC after: 1 week