[IMPROVED] Avoid stream locks for certain operations that could block routes/gateways.

server/consumer.go

@@ -1,4 +1,4 @@
-// Copyright 2019-2023 The NATS Authors
+// Copyright 2019-2024 The NATS Authors
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
 // You may obtain a copy of the License at
@@ -707,16 +707,16 @@ func (mset *stream) addConsumer(config *ConsumerConfig) (*consumer, error) {
 }
 
 func (mset *stream) addConsumerWithAssignment(config *ConsumerConfig, oname string, ca *consumerAssignment, isRecovering bool, action ConsumerAction) (*consumer, error) {
-	mset.mu.RLock()
-	s, jsa, tierName, cfg, acc, closed := mset.srv, mset.jsa, mset.tier, mset.cfg, mset.acc, mset.closed
-	retention := cfg.Retention
-	mset.mu.RUnlock()
-
 	// Check if this stream has closed.
-	if closed {
+	if mset.closed.Load() {
 		return nil, NewJSStreamInvalidError()
 	}
 
+	mset.mu.RLock()
+	s, jsa, tierName, cfg, acc := mset.srv, mset.jsa, mset.tier, mset.cfg, mset.acc
+	retention := cfg.Retention
+	mset.mu.RUnlock()
+
 	// If we do not have the consumer currently assigned to us in cluster mode we will proceed but warn.
 	// This can happen on startup with restored state where on meta replay we still do not have
 	// the assignment. Running in single server mode this always returns true.

server/filestore.go

@@ -1,4 +1,4 @@
-// Copyright 2019-2023 The NATS Authors
+// Copyright 2019-2024 The NATS Authors
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
 // You may obtain a copy of the License at

server/filestore_test.go

@@ -1,4 +1,4 @@
-// Copyright 2019-2023 The NATS Authors
+// Copyright 2019-2024 The NATS Authors
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
 // You may obtain a copy of the License at

server/jetstream_api.go

@@ -3717,7 +3717,7 @@ func (s *Server) streamSnapshot(ci *ClientInfo, acc *Account, mset *stream, sr *
 
 	// We will place sequence number and size of chunk sent in the reply.
 	ackSubj := fmt.Sprintf(jsSnapshotAckT, mset.name(), nuid.Next())
-	ackSub, _ := mset.subscribeInternalUnlocked(ackSubj+".>", func(_ *subscription, _ *client, _ *Account, subject, _ string, _ []byte) {
+	ackSub, _ := mset.subscribeInternal(ackSubj+".>", func(_ *subscription, _ *client, _ *Account, subject, _ string, _ []byte) {
 		cs, _ := strconv.Atoi(tokenAt(subject, 6))
 		// This is very crude and simple, but ok for now.
 		// This only matters when sending multiple chunks.
@@ -3728,7 +3728,7 @@ func (s *Server) streamSnapshot(ci *ClientInfo, acc *Account, mset *stream, sr *
 			}
 		}
 	})
-	defer mset.unsubscribeUnlocked(ackSub)
+	defer mset.unsubscribe(ackSub)
 
 	// TODO(dlc) - Add in NATS-Chunked-Sequence header
 

server/jetstream_cluster.go

@@ -7748,21 +7748,15 @@ func (mset *stream) hasCatchupPeers() bool {
 }
 
 func (mset *stream) setCatchingUp() {
-	mset.mu.Lock()
-	mset.catchup = true
-	mset.mu.Unlock()
+	mset.catchup.Store(true)
 }
 
 func (mset *stream) clearCatchingUp() {
-	mset.mu.Lock()
-	mset.catchup = false
-	mset.mu.Unlock()
+	mset.catchup.Store(false)
 }
 
 func (mset *stream) isCatchingUp() bool {
-	mset.mu.RLock()
-	defer mset.mu.RUnlock()
-	return mset.catchup
+	return mset.catchup.Load()
 }
 
 // Determine if a non-leader is current.
@@ -7771,7 +7765,7 @@ func (mset *stream) isCurrent() bool {
 	if mset.node == nil {
 		return true
 	}
-	return mset.node.Current() && !mset.catchup
+	return mset.node.Current() && !mset.catchup.Load()
 }
 
 // Maximum requests for the whole server that can be in flight at the same time.

server/memstore_test.go

@@ -1,4 +1,4 @@
-// Copyright 2019-2023 The NATS Authors
+// Copyright 2019-2024 The NATS Authors
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
 // You may obtain a copy of the License at

server/norace_test.go

@@ -1,4 +1,4 @@
-// Copyright 2018-2023 The NATS Authors
+// Copyright 2018-2024 The NATS Authors
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
 // You may obtain a copy of the License at

server/store.go

@@ -1,4 +1,4 @@
-// Copyright 2019-2023 The NATS Authors
+// Copyright 2019-2024 The NATS Authors
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
 // You may obtain a copy of the License at