From 990fc415f732f8e5afd2dcd7ae6602af2924e25d Mon Sep 17 00:00:00 2001
From: Krishnan Parthasarathi <krisis@users.noreply.github.com>
Date: Tue, 7 Feb 2023 23:11:42 -0800
Subject: [PATCH] Ensure safety of transitionState at startup (#16563)

---
 cmd/bucket-lifecycle.go | 28 +++++++++++++++++++---------
 cmd/server-main.go      |  4 ++--
 2 files changed, 21 insertions(+), 11 deletions(-)

diff --git a/cmd/bucket-lifecycle.go b/cmd/bucket-lifecycle.go
index eb3af59b3..e80c40a9a 100644
--- a/cmd/bucket-lifecycle.go
+++ b/cmd/bucket-lifecycle.go
@@ -180,20 +180,32 @@ func (t *transitionState) queueTransitionTask(oi ObjectInfo, sc string) {
 
 var globalTransitionState *transitionState
 
-func newTransitionState(ctx context.Context, objAPI ObjectLayer) *transitionState {
+// newTransitionState returns a transitionState object ready to be initialized
+// via its Init method.
+func newTransitionState(ctx context.Context) *transitionState {
 	return &transitionState{
 		transitionCh: make(chan transitionTask, 10000),
 		ctx:          ctx,
-		objAPI:       objAPI,
 		killCh:       make(chan struct{}),
 		lastDayStats: make(map[string]*lastDayTierStats),
 	}
 }
 
+// Init initializes t with given objAPI and instantiates the configured number
+// of transition workers.
+func (t *transitionState) Init(objAPI ObjectLayer) {
+	n := globalAPIConfig.getTransitionWorkers()
+	t.mu.Lock()
+	defer t.mu.Unlock()
+
+	t.objAPI = objAPI
+	t.updateWorkers(n)
+}
+
 // PendingTasks returns the number of ILM transition tasks waiting for a worker
 // goroutine.
 func (t *transitionState) PendingTasks() int {
-	return len(globalTransitionState.transitionCh)
+	return len(t.transitionCh)
 }
 
 // ActiveTasks returns the number of active (ongoing) ILM transition tasks.
@@ -259,6 +271,10 @@ func (t *transitionState) UpdateWorkers(n int) {
 	t.mu.Lock()
 	defer t.mu.Unlock()
 
+	t.updateWorkers(n)
+}
+
+func (t *transitionState) updateWorkers(n int) {
 	for t.numWorkers < n {
 		go t.worker(t.ctx, t.objAPI)
 		t.numWorkers++
@@ -270,12 +286,6 @@ func (t *transitionState) UpdateWorkers(n int) {
 	}
 }
 
-func initBackgroundTransition(ctx context.Context, objectAPI ObjectLayer) {
-	globalTransitionState = newTransitionState(ctx, objectAPI)
-	n := globalAPIConfig.getTransitionWorkers()
-	globalTransitionState.UpdateWorkers(n)
-}
-
 var errInvalidStorageClass = errors.New("invalid storage class")
 
 func validateTransitionTier(lc *lifecycle.Lifecycle) error {
diff --git a/cmd/server-main.go b/cmd/server-main.go
index feb9f4d70..3678ef389 100644
--- a/cmd/server-main.go
+++ b/cmd/server-main.go
@@ -323,6 +323,7 @@ func initAllSubsystems(ctx context.Context) {
 	// Create new ILM tier configuration subsystem
 	globalTierConfigMgr = NewTierConfigMgr()
 
+	globalTransitionState = newTransitionState(GlobalContext)
 	globalSiteResyncMetrics = newSiteResyncMetrics(GlobalContext)
 }
 
@@ -674,8 +675,7 @@ func serverMain(ctx *cli.Context) {
 		// Initialize background replication
 		initBackgroundReplication(GlobalContext, newObject)
 
-		// Initialize background transition
-		initBackgroundTransition(GlobalContext, newObject)
+		globalTransitionState.Init(newObject)
 
 		// Initialize batch job pool.
 		globalBatchJobPool = newBatchJobPool(GlobalContext, newObject, 100)