mrf: Avoid rare data race and more simplification (#12791)

This change avoids a rare data race and simplify the function that
returns MRF last activity information.

cmd/global-heal.go

@@ -68,17 +68,6 @@ func newBgHealSequence() *healSequence {
 	}
 }
 
-func getCurrentMRFStatus() madmin.MRFStatus {
-	mrfInfo := globalMRFState.getCurrentMRFRoundInfo()
-	return madmin.MRFStatus{
-		BytesHealed: mrfInfo.bytesHealed,
-		ItemsHealed: mrfInfo.itemsHealed,
-		TotalItems:  mrfInfo.itemsHealed + mrfInfo.pendingItems,
-		TotalBytes:  mrfInfo.bytesHealed + mrfInfo.pendingBytes,
-		Started:     mrfInfo.triggeredAt,
-	}
-}
-
 // getBackgroundHealStatus will return the
 func getBackgroundHealStatus(ctx context.Context, o ObjectLayer) (madmin.BgHealState, bool) {
 	if globalBackgroundHealState == nil {
@@ -94,9 +83,9 @@ func getBackgroundHealStatus(ctx context.Context, o ObjectLayer) (madmin.BgHealS
 		ScannedItemsCount: bgSeq.getScannedItemsCount(),
 	}
 
-	if globalMRFState != nil {
+	if globalMRFState.initialized() {
 		status.MRF = map[string]madmin.MRFStatus{
-			globalLocalNodeName: getCurrentMRFStatus(),
+			globalLocalNodeName: globalMRFState.getCurrentMRFRoundInfo(),
 		}
 	}
 

cmd/globals.go

@@ -293,7 +293,7 @@ var (
 	globalBackgroundHealRoutine *healRoutine
 	globalBackgroundHealState   *allHealState
 
-	globalMRFState *mrfState
+	globalMRFState mrfState
 
 	// If writes to FS backend should be O_SYNC.
 	globalFSOSync bool

cmd/mrf.go

@@ -20,6 +20,7 @@ package cmd
 import (
 	"context"
 	"sync"
+	"sync/atomic"
 	"time"
 
 	"github.com/minio/madmin-go"
@@ -48,19 +49,11 @@ type setInfo struct {
 	index, pool int
 }
 
-type mrfStats struct {
-	triggeredAt time.Time
-
-	itemsHealed uint64
-	bytesHealed uint64
-
-	pendingItems uint64
-	pendingBytes uint64
-}
-
 // mrfState sncapsulates all the information
 // related to the global background MRF.
 type mrfState struct {
+	ready int32
+
 	ctx       context.Context
 	objectAPI ObjectLayer
 
@@ -77,9 +70,30 @@ type mrfState struct {
 	triggeredAt time.Time
 }
 
+// Initialize healing MRF subsystem
+func (m *mrfState) init(ctx context.Context, objAPI ObjectLayer) {
+	m.mu.Lock()
+	defer m.mu.Unlock()
+
+	m.ctx = ctx
+	m.objectAPI = objAPI
+	m.opCh = make(chan partialOperation, mrfOpsQueueSize)
+	m.pendingOps = make(map[partialOperation]setInfo)
+	m.setReconnectEvent = make(chan setInfo)
+
+	go globalMRFState.maintainMRFList()
+	go globalMRFState.healRoutine()
+
+	atomic.StoreInt32(&m.ready, 1)
+}
+
+func (m *mrfState) initialized() bool {
+	return atomic.LoadInt32(&m.ready) != 0
+}
+
 // Add a partial S3 operation (put/delete) when one or more disks are offline.
 func (m *mrfState) addPartialOp(op partialOperation) {
-	if m == nil {
+	if !m.initialized() {
 		return
 	}
 
@@ -91,7 +105,7 @@ func (m *mrfState) addPartialOp(op partialOperation) {
 
 // Receive the new set (disk) reconnection event
 func (m *mrfState) newSetReconnected(pool, set int) {
-	if m == nil {
+	if !m.initialized() {
 		return
 	}
 
@@ -104,8 +118,8 @@ func (m *mrfState) newSetReconnected(pool, set int) {
 	}
 }
 
-// Get current MRF stats
-func (m *mrfState) getCurrentMRFRoundInfo() mrfStats {
+// Get current MRF stats of the last MRF activity
+func (m *mrfState) getCurrentMRFRoundInfo() madmin.MRFStatus {
 	m.mu.Lock()
 	triggeredAt := m.triggeredAt
 	itemsHealed := m.itemsHealed
@@ -115,15 +129,15 @@ func (m *mrfState) getCurrentMRFRoundInfo() mrfStats {
 	m.mu.Unlock()
 
 	if pendingItems == 0 {
-		return mrfStats{}
+		return madmin.MRFStatus{}
 	}
 
-	return mrfStats{
-		triggeredAt:  triggeredAt,
-		itemsHealed:  itemsHealed,
-		bytesHealed:  bytesHealed,
-		pendingItems: pendingItems,
-		pendingBytes: pendingBytes,
+	return madmin.MRFStatus{
+		Started:     triggeredAt,
+		ItemsHealed: itemsHealed,
+		BytesHealed: bytesHealed,
+		TotalItems:  itemsHealed + pendingItems,
+		TotalBytes:  bytesHealed + pendingBytes,
 	}
 }
 
@@ -230,13 +244,5 @@ func (m *mrfState) healRoutine() {
 
 // Initialize healing MRF
 func initHealMRF(ctx context.Context, obj ObjectLayer) {
-	globalMRFState = &mrfState{
-		ctx:               ctx,
-		objectAPI:         obj,
-		opCh:              make(chan partialOperation, mrfOpsQueueSize),
-		pendingOps:        make(map[partialOperation]setInfo),
-		setReconnectEvent: make(chan setInfo),
-	}
-	go globalMRFState.maintainMRFList()
-	go globalMRFState.healRoutine()
+	globalMRFState.init(ctx, obj)
 }