From d635711daa98be86d4c7fd01499c34f566b54ccb Mon Sep 17 00:00:00 2001
From: André Fabian Silva Delgado <emulatorman@parabola.nu>
Date: Fri, 10 Jun 2016 05:30:17 -0300
Subject: Linux-libre 4.6.2-gnu

---
 fs/nfs/callback_proc.c | 71 +++++++++++++++++++++++++++-----------------------
 1 file changed, 39 insertions(+), 32 deletions(-)

(limited to 'fs/nfs/callback_proc.c')

diff --git a/fs/nfs/callback_proc.c b/fs/nfs/callback_proc.c
index f0939d097..7c9fbf504 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 +482,28 @@ __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) {
+		status = htonl(NFS4ERR_REP_TOO_BIG_TO_CACHE);
+		goto out_unlock;
+	}
 
 	/*
 	 * Check for pending referring calls.  If a match is found, a
@@ -513,7 +520,7 @@ __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);
 
-- 
cgit v1.2.3-54-g00ecf