refactor healing to remove certain structs (#13079)

- remove sourceCh usage from healing
  we already have tasks and resp channel

- use read locks to lookup globalHealConfig

- fix healing resolver to pick candidates quickly
  that need healing, without this resolver was
  unexpectedly skipping.

cmd/admin-heal-ops.go

@@ -396,9 +396,6 @@ type healSequence struct {
 	// bucket, and object on which heal seq. was initiated
 	bucket, object string
 
-	// A channel of entities (format, buckets, objects) to heal
-	sourceCh chan healSource
-
 	// A channel of entities with heal result
 	respCh chan healResult
 
@@ -648,11 +645,7 @@ func (h *healSequence) healSequenceStart(objAPI ObjectLayer) {
 	h.currentStatus.StartTime = UTCNow()
 	h.mutex.Unlock()
 
-	if h.sourceCh == nil {
-		go h.traverseAndHeal(objAPI)
-	} else {
-		go h.healFromSourceCh()
-	}
+	go h.traverseAndHeal(objAPI)
 
 	select {
 	case err, ok := <-h.traverseAndHealDoneCh:
@@ -696,10 +689,6 @@ func (h *healSequence) logHeal(healType madmin.HealItemType) {
 }
 
 func (h *healSequence) queueHealTask(source healSource, healType madmin.HealItemType) error {
-	globalHealConfigMu.Lock()
-	opts := globalHealConfig
-	globalHealConfigMu.Unlock()
-
 	// Send heal request
 	task := healTask{
 		bucket:     source.bucket,
@@ -711,9 +700,7 @@ func (h *healSequence) queueHealTask(source healSource, healType madmin.HealItem
 	if source.opts != nil {
 		task.opts = *source.opts
 	}
-	if opts.Bitrot {
-		task.opts.ScanMode = madmin.HealDeepScan
-	}
+	task.opts.ScanMode = globalHealConfig.ScanMode()
 
 	h.mutex.Lock()
 	h.scannedItemsMap[healType]++
@@ -773,48 +760,6 @@ func (h *healSequence) queueHealTask(source healSource, healType madmin.HealItem
 	}
 }
 
-func (h *healSequence) healItemsFromSourceCh() error {
-	for {
-		select {
-		case source, ok := <-h.sourceCh:
-			if !ok {
-				return nil
-			}
-
-			var itemType madmin.HealItemType
-			switch source.bucket {
-			case nopHeal:
-				continue
-			case SlashSeparator:
-				itemType = madmin.HealItemMetadata
-			default:
-				if source.object == "" {
-					itemType = madmin.HealItemBucket
-				} else {
-					itemType = madmin.HealItemObject
-				}
-			}
-
-			if err := h.queueHealTask(source, itemType); err != nil {
-				switch err.(type) {
-				case ObjectExistsAsDirectory:
-				case ObjectNotFound:
-				case VersionNotFound:
-				default:
-					logger.LogIf(h.ctx, fmt.Errorf("Heal attempt failed for %s: %w",
-						pathJoin(source.bucket, source.object), err))
-				}
-			}
-		case <-h.ctx.Done():
-			return nil
-		}
-	}
-}
-
-func (h *healSequence) healFromSourceCh() {
-	h.healItemsFromSourceCh()
-}
-
 func (h *healSequence) healDiskMeta(objAPI ObjectLayer) error {
 	// Start healing the config prefix.
 	return h.healMinioSysMeta(objAPI, minioConfigPrefix)()