[#874] engine: Revert Check object existance concurrently

This reverts commit f526f49995.

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

pkg/local_object_storage/engine/exists.go

@@ -3,70 +3,54 @@ package engine
 import (
 	"context"
 	"errors"
-	"sync/atomic"
 
 	"git.frostfs.info/TrueCloudLab/frostfs-node/pkg/local_object_storage/shard"
 	"git.frostfs.info/TrueCloudLab/frostfs-sdk-go/client"
 	apistatus "git.frostfs.info/TrueCloudLab/frostfs-sdk-go/client/status"
 	objectSDK "git.frostfs.info/TrueCloudLab/frostfs-sdk-go/object"
 	oid "git.frostfs.info/TrueCloudLab/frostfs-sdk-go/object/id"
-	"golang.org/x/sync/errgroup"
 )
 
 func (e *StorageEngine) exists(ctx context.Context, addr oid.Address) (bool, error) {
 	var shPrm shard.ExistsPrm
 	shPrm.SetAddress(addr)
-
-	var exists atomic.Bool
-	eg, egCtx := errgroup.WithContext(ctx)
-	egCtx, cancel := context.WithCancel(egCtx)
-	defer cancel()
+	alreadyRemoved := false
+	exists := false
 
 	e.iterateOverSortedShards(addr, func(_ int, sh hashedShard) (stop bool) {
-		select {
-		case <-egCtx.Done():
-			return true
-		default:
+		res, err := sh.Exists(ctx, shPrm)
+		if err != nil {
+			if client.IsErrObjectAlreadyRemoved(err) {
+				alreadyRemoved = true
+
+				return true
+			}
+
+			var siErr *objectSDK.SplitInfoError
+			if errors.As(err, &siErr) {
+				return true
+			}
+
+			if shard.IsErrObjectExpired(err) {
+				return true
+			}
+
+			if !client.IsErrObjectNotFound(err) {
+				e.reportShardError(sh, "could not check existence of object in shard", err)
+			}
+			return false
 		}
 
-		eg.Go(func() error {
-			res, err := sh.Exists(egCtx, shPrm)
-			if err != nil {
-				if errors.Is(err, context.Canceled) {
-					return err
-				}
+		if !exists {
+			exists = res.Exists()
+		}
 
-				if client.IsErrObjectAlreadyRemoved(err) {
-					return err
-				}
-
-				var siErr *objectSDK.SplitInfoError
-				if errors.As(err, &siErr) {
-					return err
-				}
-
-				if shard.IsErrObjectExpired(err) {
-					return err
-				}
-
-				if !client.IsErrObjectNotFound(err) {
-					e.reportShardError(sh, "could not check existence of object in shard", err)
-				}
-				return nil
-			}
-			if res.Exists() {
-				exists.Store(true)
-				cancel()
-			}
-			return nil
-		})
 		return false
 	})
 
-	err := eg.Wait()
-	if client.IsErrObjectAlreadyRemoved(err) {
+	if alreadyRemoved {
 		return false, new(apistatus.ObjectAlreadyRemoved)
 	}
 
-	return exists.Load(), nil
+	return exists, nil
 }