fix: background heal rely on getOnlineDisks() (#10687)

cmd/background-newdisks-heal-ops.go

@@ -164,7 +164,7 @@ func monitorLocalDisksAndHeal(ctx context.Context, z *erasureZones, bgSeq *healS
 					for _, disk := range disks {
 						logger.Info("Healing disk '%s' on %s zone", disk, humanize.Ordinal(i+1))
 
-						lbDisks := z.zones[i].sets[setIndex].getLoadBalancedNDisks(z.zones[i].listTolerancePerSet)
+						lbDisks := z.zones[i].sets[setIndex].getOnlineDisks()
 						if err := healErasureSet(ctx, setIndex, buckets, lbDisks); err != nil {
 							logger.LogIf(ctx, err)
 							continue

cmd/erasure-common.go

@@ -75,6 +75,9 @@ func (er erasureObjects) getOnlineDisks() (newDisks []StorageAPI) {
 func (er erasureObjects) getLoadBalancedNDisks(ndisks int) (newDisks []StorageAPI) {
 	disks := er.getLoadBalancedDisks(ndisks != -1)
 	for _, disk := range disks {
+		if disk == nil {
+			continue
+		}
 		newDisks = append(newDisks, disk)
 		ndisks--
 		if ndisks == 0 {

cmd/erasure-sets.go

@@ -1026,6 +1026,7 @@ func (s *erasureSets) startMergeWalksVersionsN(ctx context.Context, bucket, pref
 			wg.Add(1)
 			go func(disk StorageAPI) {
 				defer wg.Done()
+
 				entryCh, err := disk.WalkVersions(GlobalContext, bucket, prefix, marker, recursive, endWalkCh)
 				if err != nil {
 					return