NFSv4.x: CB_SEQUENCE should return NFS4ERR_DELAY if still executing

See RFC5661 Section 2.10.6.2: if retrying a request, and the old one is
still in progress, we must return NFS4ERR_DELAY as the reply to sequence.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/fs/nfs/callback_proc.c b/fs/nfs/callback_proc.c
index 83a66a8f40f2..e0844fdbd9ac 100644
--- a/fs/nfs/callback_proc.c
+++ b/fs/nfs/callback_proc.c
@@ -375,6 +375,8 @@ validate_seqid(struct nfs4_slot_table *tbl, struct cb_sequenceargs * args)
         if (args->csa_sequenceid == slot->seq_nr) {
                 dprintk("%s seqid %u is a replay\n",
                         __func__, args->csa_sequenceid);
+                if (tbl->highest_used_slotid != NFS4_NO_SLOT)
+                        return htonl(NFS4ERR_DELAY);
                 /* Signal process_op to set this error on next op */
                 if (args->csa_cachethis == 0)
                         return htonl(NFS4ERR_RETRY_UNCACHED_REP);