nfs: Only update callback sequnce id when CB_SEQUENCE success

When testing pnfs layout, nfsd got error NFS4ERR_SEQ_MISORDERED.
It is caused by nfs return NFS4ERR_DELAY before validate_seqid(),
don't update the sequnce id, but nfsd updates the sequnce id !!!

According to RFC5661 20.9.3,
" If CB_SEQUENCE returns an error, then the state of the slot
  (sequence ID, cached reply) MUST NOT change. "

Signed-off-by: Kinglong Mee <kinglongmee@gmail.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>

1 files changed, 12 insertions, 4 deletions

diff --git a/fs/nfs/callback_proc.c b/fs/nfs/callback_proc.c
index 197806fb87ff..7e9653aae5d8 100644
--- a/fs/nfs/callback_proc.c
+++ b/fs/nfs/callback_proc.c
@@ -327,10 +327,8 @@ validate_seqid(struct nfs4_slot_table *tbl, struct cb_sequenceargs * args)
         dprintk("%s slot table seqid: %u\n", __func__, slot->seq_nr);
 
         /* Normal */
-        if (likely(args->csa_sequenceid == slot->seq_nr + 1)) {
-                slot->seq_nr++;
+        if (likely(args->csa_sequenceid == slot->seq_nr + 1))
                 goto out_ok;
-        }
 
         /* Replay */
         if (args->csa_sequenceid == slot->seq_nr) {
@@ -418,6 +416,7 @@ __be32 nfs4_callback_sequence(struct cb_sequenceargs *args,
                               struct cb_process_state *cps)
 {
         struct nfs4_slot_table *tbl;
+        struct nfs4_slot *slot;
         struct nfs_client *clp;
         int i;
         __be32 status = htonl(NFS4ERR_BADSESSION);
@@ -429,7 +428,9 @@ __be32 nfs4_callback_sequence(struct cb_sequenceargs *args,
 
         if (!(clp->cl_session->flags & SESSION4_BACK_CHAN))
                 goto out;
+
         tbl = &clp->cl_session->bc_slot_table;
+        slot = tbl->slots + args->csa_slotid;
 
         spin_lock(&tbl->slot_tbl_lock);
         /* state manager is resetting the session */
@@ -444,7 +445,7 @@ __be32 nfs4_callback_sequence(struct cb_sequenceargs *args,
                 goto out;
         }
 
-        status = validate_seqid(&clp->cl_session->bc_slot_table, args);
+        status = validate_seqid(tbl, args);
         spin_unlock(&tbl->slot_tbl_lock);
         if (status)
                 goto out;
@@ -468,6 +469,13 @@ __be32 nfs4_callback_sequence(struct cb_sequenceargs *args,
         res->csr_highestslotid = NFS41_BC_MAX_CALLBACKS - 1;
         res->csr_target_highestslotid = NFS41_BC_MAX_CALLBACKS - 1;
 
+        /*
+         * RFC5661 20.9.3
+         * If CB_SEQUENCE returns an error, then the state of the slot
+         * (sequence ID, cached reply) MUST NOT change.
+         */
+        slot->seq_nr++;
+
 out:
         cps->clp = clp; /* put in nfs4_callback_compound */
         for (i = 0; i < args->csa_nrclists; i++)