This allows to reduce open/close DBs to check incompleted rebuilds.

Signed-off-by: Dmitrii Stepanov <d.stepanov@yadro.com>

@@ -110,0 +135,4 @@
+		return nil, fmt.Errorf("invalid fill percent value %d: must be (0; 100]", target)
+	}
+	result := make(map[string]struct{})
+	if err := b.iterateDeepest(ctx, oid.Address{}, func(lvlPath string) (bool, error) {

@@ -110,0 +157,4 @@
+		if !hasDBs {
+			return false, nil
+		}
+		for _, e := range entries {

@@ -414,4 +401,1 @@
 
-// WithDisabledRebuild returns an option to disable a shard rebuild.
-// For testing purposes only.
-func WithDisabledRebuild() Option {

@@ -0,0 +18,4 @@
+var shardsRebuildCmd = &cobra.Command{
+	Use:   "rebuild",
+	Short: "Rebuild shards",
+	Long:  "Rebuild reclaims storage occupied by dead objects",

@@ -193,3 +193,3 @@
 }
 
-func (b *Blobovniczas) iterateExistingDBPathsDFS(ctx context.Context, path string, f func(string) (bool, error)) (bool, error) {
+func (b *Blobovniczas) iterateExistingDBPathsDFS(ctx context.Context, path string, f func(string) (bool, error), fileFilter func(path string) bool) (bool, error) {

@@ -114,0 +187,4 @@
+		return false, err
+	}
+	defer shDB.Close()
+	return blz.FillPercent() < targetFillPercent || blz.IsOverflowed(), nil

@@ -155,6 +164,7 @@ func testRebuildFailoverValidate(t *testing.T, dir string, obj *objectSDK.Object
 	rRes, err := b.Rebuild(context.Background(), common.RebuildPrm{
 		MetaStorage:   metaStub,
 		WorkerLimiter: &rebuildLimiterStub{},
+		FillPercent:   1,

@@ -0,0 +31,4 @@
+	ctx, span := tracing.StartSpanFromContext(ctx, "StorageEngine.Rebuild",
+		trace.WithAttributes(
+			attribute.Int("shard_id_count", len(prm.ShardIDs)),
+			attribute.Int64("target_fill_percent", int64(prm.TargetFillPercent)),