1 files changed, 37 insertions, 32 deletions

diff --git a/fs/nfs/callback_proc.c b/fs/nfs/callback_proc.c
index f0939d097406..618ced381a14 100644
--- a/fs/nfs/callback_proc.c
+++ b/fs/nfs/callback_proc.c
@@ -354,47 +354,38 @@ out:
  * a single outstanding callback request at a time.
  */
 static __be32
-validate_seqid(struct nfs4_slot_table *tbl, struct cb_sequenceargs * args)
+validate_seqid(const struct nfs4_slot_table *tbl, const struct nfs4_slot *slot,
+                const struct cb_sequenceargs * args)
 {
-        struct nfs4_slot *slot;
-
-        dprintk("%s enter. slotid %u seqid %u\n",
-                __func__, args->csa_slotid, args->csa_sequenceid);
+        dprintk("%s enter. slotid %u seqid %u, slot table seqid: %u\n",
+                __func__, args->csa_slotid, args->csa_sequenceid, slot->seq_nr);
 
-        if (args->csa_slotid >= NFS41_BC_MAX_CALLBACKS)
+        if (args->csa_slotid > tbl->server_highest_slotid)
                 return htonl(NFS4ERR_BADSLOT);
 
-        slot = tbl->slots + args->csa_slotid;
-        dprintk("%s slot table seqid: %u\n", __func__, slot->seq_nr);
-
-        /* Normal */
-        if (likely(args->csa_sequenceid == slot->seq_nr + 1))
-                goto out_ok;
-
         /* Replay */
         if (args->csa_sequenceid == slot->seq_nr) {
                 dprintk("%s seqid %u is a replay\n",
                         __func__, args->csa_sequenceid);
+                if (nfs4_test_locked_slot(tbl, slot->slot_nr))
+                        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);
 
-                /* The ca_maxresponsesize_cached is 0 with no DRC */
-                else if (args->csa_cachethis == 1)
-                        return htonl(NFS4ERR_REP_TOO_BIG_TO_CACHE);
+                /* Liar! We never allowed you to set csa_cachethis != 0 */
+                return htonl(NFS4ERR_SEQ_FALSE_RETRY);
         }
 
         /* Wraparound */
-        if (args->csa_sequenceid == 1 && (slot->seq_nr + 1) == 0) {
-                slot->seq_nr = 1;
-                goto out_ok;
-        }
+        if (unlikely(slot->seq_nr == 0xFFFFFFFFU)) {
+                if (args->csa_sequenceid == 1)
+                        return htonl(NFS4_OK);
+        } else if (likely(args->csa_sequenceid == slot->seq_nr + 1))
+                return htonl(NFS4_OK);
 
         /* Misordered request */
         return htonl(NFS4ERR_SEQ_MISORDERED);
-out_ok:
-        tbl->highest_used_slotid = args->csa_slotid;
-        return htonl(NFS4_OK);
 }
 
 /*
@@ -473,6 +464,12 @@ __be32 nfs4_callback_sequence(struct cb_sequenceargs *args,
         tbl = &clp->cl_session->bc_slot_table;
         slot = tbl->slots + args->csa_slotid;
 
+        /* Set up res before grabbing the spinlock */
+        memcpy(&res->csr_sessionid, &args->csa_sessionid,
+               sizeof(res->csr_sessionid));
+        res->csr_sequenceid = args->csa_sequenceid;
+        res->csr_slotid = args->csa_slotid;
+
         spin_lock(&tbl->slot_tbl_lock);
         /* state manager is resetting the session */
         if (test_bit(NFS4_SLOT_TBL_DRAINING, &tbl->slot_tbl_state)) {
@@ -485,18 +482,26 @@ __be32 nfs4_callback_sequence(struct cb_sequenceargs *args,
                 goto out_unlock;
         }
 
-        memcpy(&res->csr_sessionid, &args->csa_sessionid,
-               sizeof(res->csr_sessionid));
-        res->csr_sequenceid = args->csa_sequenceid;
-        res->csr_slotid = args->csa_slotid;
-        res->csr_highestslotid = NFS41_BC_MAX_CALLBACKS - 1;
-        res->csr_target_highestslotid = NFS41_BC_MAX_CALLBACKS - 1;
+        status = htonl(NFS4ERR_BADSLOT);
+        slot = nfs4_lookup_slot(tbl, args->csa_slotid);
+        if (IS_ERR(slot))
+                goto out_unlock;
+
+        res->csr_highestslotid = tbl->server_highest_slotid;
+        res->csr_target_highestslotid = tbl->target_highest_slotid;
 
-        status = validate_seqid(tbl, args);
+        status = validate_seqid(tbl, slot, args);
         if (status)
                 goto out_unlock;
+        if (!nfs4_try_to_lock_slot(tbl, slot)) {
+                status = htonl(NFS4ERR_DELAY);
+                goto out_unlock;
+        }
+        cps->slot = slot;
 
-        cps->slotid = args->csa_slotid;
+        /* The ca_maxresponsesize_cached is 0 with no DRC */
+        if (args->csa_cachethis != 0)
+                return htonl(NFS4ERR_REP_TOO_BIG_TO_CACHE);
 
         /*
          * Check for pending referring calls.  If a match is found, a
@@ -513,7 +518,7 @@ __be32 nfs4_callback_sequence(struct cb_sequenceargs *args,
          * If CB_SEQUENCE returns an error, then the state of the slot
          * (sequence ID, cached reply) MUST NOT change.
          */
-        slot->seq_nr++;
+        slot->seq_nr = args->csa_sequenceid;
 out_unlock:
         spin_unlock(&tbl->slot_tbl_lock);