1 files changed, 71 insertions, 2 deletions

diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index dfc6d946cdfe..24b6e0593184 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -1000,6 +1000,32 @@ error:
         return status;
 }
 
+static int
+check_slot_seqid(u32 seqid, struct nfsd4_slot *slot)
+{
+        dprintk("%s enter. seqid %d slot->sl_seqid %d\n", __func__, seqid,
+                slot->sl_seqid);
+
+        /* The slot is in use, and no response has been sent. */
+        if (slot->sl_inuse) {
+                if (seqid == slot->sl_seqid)
+                        return nfserr_jukebox;
+                else
+                        return nfserr_seq_misordered;
+        }
+        /* Normal */
+        if (likely(seqid == slot->sl_seqid + 1))
+                return nfs_ok;
+        /* Replay */
+        if (seqid == slot->sl_seqid)
+                return nfserr_replay_cache;
+        /* Wraparound */
+        if (seqid == 1 && (slot->sl_seqid + 1) == 0)
+                return nfs_ok;
+        /* Misordered replay or misordered new request */
+        return nfserr_seq_misordered;
+}
+
 __be32
 nfsd4_create_session(struct svc_rqst *rqstp,
                      struct nfsd4_compound_state *cstate,
@@ -1017,11 +1043,54 @@ nfsd4_destroy_session(struct svc_rqst *r,
 }
 
 __be32
-nfsd4_sequence(struct svc_rqst *r,
+nfsd4_sequence(struct svc_rqst *rqstp,
                struct nfsd4_compound_state *cstate,
                struct nfsd4_sequence *seq)
 {
-        return -1;      /* stub */
+        struct nfsd4_session *session;
+        struct nfsd4_slot *slot;
+        int status;
+
+        spin_lock(&sessionid_lock);
+        status = nfserr_badsession;
+        session = find_in_sessionid_hashtbl(&seq->sessionid);
+        if (!session)
+                goto out;
+
+        status = nfserr_badslot;
+        if (seq->slotid >= session->se_fnumslots)
+                goto out;
+
+        slot = &session->se_slots[seq->slotid];
+        dprintk("%s: slotid %d\n", __func__, seq->slotid);
+
+        status = check_slot_seqid(seq->seqid, slot);
+        if (status == nfserr_replay_cache) {
+                cstate->slot = slot;
+                cstate->session = session;
+                goto replay_cache;
+        }
+        if (status)
+                goto out;
+
+        /* Success! bump slot seqid */
+        slot->sl_inuse = true;
+        slot->sl_seqid = seq->seqid;
+
+        cstate->slot = slot;
+        cstate->session = session;
+
+replay_cache:
+        /* Renew the clientid on success and on replay.
+         * Hold a session reference until done processing the compound:
+         * nfsd4_put_session called only if the cstate slot is set.
+         */
+        renew_client(session->se_client);
+        nfsd4_get_session(session);
+out:
+        spin_unlock(&sessionid_lock);
+        dprintk("%s: return %d\n", __func__, ntohl(status));
+        return status;
 }
 
 __be32