From ab32067152352c54016de4a256fa83de2d598377 Mon Sep 17 00:00:00 2001
From: Dmitrii Stepanov <d.stepanov@yadro.com>
Date: Tue, 28 Mar 2023 18:49:13 +0300
Subject: [PATCH] [#183] gc: Fix drop expired locked complex objects

Do not delete bucket keys during iteration

Signed-off-by: Dmitrii Stepanov <d.stepanov@yadro.com>
---
 pkg/local_object_storage/metabase/lock.go | 60 ++++++++++++++++++-----
 1 file changed, 47 insertions(+), 13 deletions(-)

diff --git a/pkg/local_object_storage/metabase/lock.go b/pkg/local_object_storage/metabase/lock.go
index 6850cf61..2dcc85d4 100644
--- a/pkg/local_object_storage/metabase/lock.go
+++ b/pkg/local_object_storage/metabase/lock.go
@@ -14,6 +14,11 @@ import (
 
 var bucketNameLocked = []byte{lockedPrefix}
 
+type keyValue struct {
+	Key   []byte
+	Value []byte
+}
+
 // returns name of the bucket with objects of type LOCK for specified container.
 func bucketNameLockers(idCnr cid.ID, key []byte) []byte {
 	return bucketName(idCnr, lockersPrefix, key)
@@ -107,7 +112,7 @@ func (db *DB) FreeLockedBy(lockers []oid.Address) ([]oid.Address, error) {
 
 	var unlockedObjects []oid.Address
 
-	return unlockedObjects, db.boltDB.Update(func(tx *bbolt.Tx) error {
+	if err := db.boltDB.Update(func(tx *bbolt.Tx) error {
 		for i := range lockers {
 			unlocked, err := freePotentialLocks(tx, lockers[i].Container(), lockers[i].Object())
 			if err != nil {
@@ -117,7 +122,10 @@ func (db *DB) FreeLockedBy(lockers []oid.Address) ([]oid.Address, error) {
 		}
 
 		return nil
-	})
+	}); err != nil {
+		return nil, err
+	}
+	return unlockedObjects, nil
 }
 
 // checks if specified object is locked in the specified container.
@@ -157,7 +165,8 @@ func freePotentialLocks(tx *bbolt.Tx, idCnr cid.ID, locker oid.ID) ([]oid.Addres
 	}
 
 	keyLocker := objectKey(locker, key)
-	return unlockedObjects, bucketLockedContainer.ForEach(func(k, v []byte) error {
+	updates := make([]keyValue, 0)
+	err := bucketLockedContainer.ForEach(func(k, v []byte) error {
 		keyLockers, err := decodeList(v)
 		if err != nil {
 			return fmt.Errorf("decode list of lockers in locked bucket: %w", err)
@@ -166,11 +175,10 @@ func freePotentialLocks(tx *bbolt.Tx, idCnr cid.ID, locker oid.ID) ([]oid.Addres
 		for i := range keyLockers {
 			if bytes.Equal(keyLockers[i], keyLocker) {
 				if len(keyLockers) == 1 {
-					// locker was all alone
-					err = bucketLockedContainer.Delete(k)
-					if err != nil {
-						return fmt.Errorf("delete locked object record from locked bucket: %w", err)
-					}
+					updates = append(updates, keyValue{
+						Key:   k,
+						Value: nil,
+					})
 
 					var id oid.ID
 					err = id.Decode(k)
@@ -192,11 +200,10 @@ func freePotentialLocks(tx *bbolt.Tx, idCnr cid.ID, locker oid.ID) ([]oid.Addres
 						return fmt.Errorf("encode updated list of lockers: %w", err)
 					}
 
-					// update the record
-					err = bucketLockedContainer.Put(k, v)
-					if err != nil {
-						return fmt.Errorf("update list of lockers: %w", err)
-					}
+					updates = append(updates, keyValue{
+						Key:   k,
+						Value: v,
+					})
 				}
 
 				return nil
@@ -205,6 +212,33 @@ func freePotentialLocks(tx *bbolt.Tx, idCnr cid.ID, locker oid.ID) ([]oid.Addres
 
 		return nil
 	})
+
+	if err != nil {
+		return nil, err
+	}
+
+	if err = applyBucketUpdates(bucketLockedContainer, updates); err != nil {
+		return nil, err
+	}
+
+	return unlockedObjects, nil
+}
+
+func applyBucketUpdates(bucket *bbolt.Bucket, updates []keyValue) error {
+	for _, update := range updates {
+		if update.Value == nil {
+			err := bucket.Delete(update.Key)
+			if err != nil {
+				return fmt.Errorf("delete locked object record from locked bucket: %w", err)
+			}
+		} else {
+			err := bucket.Put(update.Key, update.Value)
+			if err != nil {
+				return fmt.Errorf("update list of lockers: %w", err)
+			}
+		}
+	}
+	return nil
 }
 
 // IsLockedPrm groups the parameters of IsLocked operation.