diff --git a/models/repo/fork.go b/models/repo/fork.go
index 39380afeb1..da00ccef40 100644
--- a/models/repo/fork.go
+++ b/models/repo/fork.go
@@ -104,11 +104,13 @@ func GetForksByUserAndOrgs(ctx context.Context, user *user_model.User, repo *Rep
 
 // ReparentFork sets the fork to be an unforked repository and the forked repo becomes its fork
 func ReparentFork(ctx context.Context, forkedRepoID, srcForkID int64) error {
-	if _, err := db.GetEngine(ctx).Table("repository").ID(srcForkID).Cols("fork_id", "is_fork").Update(&Repository{ForkID: forkedRepoID, IsFork: true}); err != nil {
-		return err
-	}
-	if _, err := db.GetEngine(ctx).Table("repository").ID(forkedRepoID).Cols("fork_id", "is_fork", "num_forks").Update(&Repository{ForkID: 0, NumForks: 1, IsFork: false}); err != nil {
-		return err
-	}
-	return nil
+	return db.WithTx(ctx, func(ctx context.Context) error {
+		if _, err := db.GetEngine(ctx).Table("repository").ID(srcForkID).Cols("fork_id", "is_fork").Update(&Repository{ForkID: forkedRepoID, IsFork: true}); err != nil {
+			return err
+		}
+		if _, err := db.GetEngine(ctx).Table("repository").ID(forkedRepoID).Cols("fork_id", "is_fork", "num_forks").Update(&Repository{ForkID: 0, NumForks: 1, IsFork: false}); err != nil {
+			return err
+		}
+		return nil
+	})
 }