heal: Fix heal sequences cleanup process (#6780)

The current code triggers a timeout to cleanup a heal seq from
healSeqMap, but we don't know if the user did or not launch a new
healing sequence with the same path.

Add endTime to healSequence struct and add a periodic heal-sequence
cleaner to remove heal sequences only if this latter is older than
10 minutes.

cmd/admin-heal-ops.go

@@ -113,6 +113,32 @@ func initAllHealState(isErasureMode bool) {
 	globalAllHealState = allHealState{
 		healSeqMap: make(map[string]*healSequence),
 	}
+
+	go globalAllHealState.periodicHealSeqsClean()
+}
+
+func (ahs *allHealState) periodicHealSeqsClean() {
+	// Launch clean-up routine to remove this heal sequence (after
+	// it ends) from the global state after timeout has elapsed.
+	ticker := time.NewTicker(time.Minute * 5)
+	defer ticker.Stop()
+	for {
+		select {
+		case <-ticker.C:
+			now := UTCNow()
+			ahs.Lock()
+			for path, h := range ahs.healSeqMap {
+				if h.hasEnded() && h.endTime.Add(keepHealSeqStateDuration).Before(now) {
+					delete(ahs.healSeqMap, path)
+				}
+			}
+			ahs.Unlock()
+		case <-globalServiceDoneCh:
+			// server could be restarting - need
+			// to exit immediately
+			return
+		}
+	}
 }
 
 // getHealSequence - Retrieve a heal sequence by path. The second
@@ -213,41 +239,6 @@ func (ahs *allHealState) LaunchNewHealSequence(h *healSequence) (
 	// Launch top-level background heal go-routine
 	go h.healSequenceStart()
 
-	// Launch clean-up routine to remove this heal sequence (after
-	// it ends) from the global state after timeout has elapsed.
-	go func() {
-		var keepStateTimeout <-chan time.Time
-		ticker := time.NewTicker(time.Minute)
-		defer ticker.Stop()
-		everyMinute := ticker.C
-		for {
-			select {
-			// Check every minute if heal sequence has ended.
-			case <-everyMinute:
-				if h.hasEnded() {
-					keepStateTimeout = time.After(keepHealSeqStateDuration)
-					everyMinute = nil
-				}
-
-			// This case does not fire until the heal
-			// sequence completes.
-			case <-keepStateTimeout:
-				// Heal sequence has ended, keep
-				// results state duration has elapsed,
-				// so purge state.
-				ahs.Lock()
-				defer ahs.Unlock()
-				delete(ahs.healSeqMap, h.path)
-				return
-
-			case <-globalServiceDoneCh:
-				// server could be restarting - need
-				// to exit immediately
-				return
-			}
-		}
-	}()
-
 	b, err := json.Marshal(madmin.HealStartSuccess{
 		ClientToken:   h.clientToken,
 		ClientAddress: h.clientAddress,
@@ -321,6 +312,9 @@ type healSequence struct {
 	// time at which heal sequence was started
 	startTime time.Time
 
+	// time at which heal sequence has ended
+	endTime time.Time
+
 	// Heal client info
 	clientToken, clientAddress string
 
@@ -498,6 +492,7 @@ func (h *healSequence) healSequenceStart() {
 
 	select {
 	case err, ok := <-h.traverseAndHealDoneCh:
+		h.endTime = UTCNow()
 		h.currentStatus.updateLock.Lock()
 		defer h.currentStatus.updateLock.Unlock()
 		// Heal traversal is complete.
@@ -511,6 +506,7 @@ func (h *healSequence) healSequenceStart() {
 		}
 
 	case <-h.stopSignalCh:
+		h.endTime = UTCNow()
 		h.currentStatus.updateLock.Lock()
 		h.currentStatus.Summary = healStoppedStatus
 		h.currentStatus.FailureDetail = errHealStopSignalled.Error()