close channel upon error in Walk()'er (#9042)

cmd/object-api-common.go

@@ -320,6 +320,8 @@ func listObjectsNonSlash(ctx context.Context, bucket, prefix, marker, delimiter
 // then Walk() stops the walker.
 func fsWalk(ctx context.Context, obj ObjectLayer, bucket, prefix string, listDir ListDirFunc, results chan<- ObjectInfo, getObjInfo func(context.Context, string, string) (ObjectInfo, error), getObjectInfoDirs ...func(context.Context, string, string) (ObjectInfo, error)) error {
 	if err := checkListObjsArgs(ctx, bucket, prefix, "", obj); err != nil {
+		// Upon error close the channel.
+		close(results)
 		return err
 	}
 

cmd/xl-sets.go

@@ -1617,6 +1617,8 @@ func (s *xlSets) ListBucketsHeal(ctx context.Context) ([]BucketInfo, error) {
 // then Walk() stops the walker.
 func (s *xlSets) Walk(ctx context.Context, bucket, prefix string, results chan<- ObjectInfo) error {
 	if err := checkListObjsArgs(ctx, bucket, prefix, "", s); err != nil {
+		// Upon error close the channel.
+		close(results)
 		return err
 	}
 

cmd/xl-zones.go

@@ -1291,6 +1291,8 @@ func (z *xlZones) HealBucket(ctx context.Context, bucket string, dryRun, remove
 // then Walk() stops the walker.
 func (z *xlZones) Walk(ctx context.Context, bucket, prefix string, results chan<- ObjectInfo) error {
 	if err := checkListObjsArgs(ctx, bucket, prefix, "", z); err != nil {
+		// Upon error close the channel.
+		close(results)
 		return err
 	}