LockForUpdate in nested Db transaction

[ankitjain0269]

I am using LockForUpdate in a nested DB transaction.

//Outer transaction 

DB::transaction(function () use ($item) {
$orderItem = new OrderItem();
$orderItem->quantity = 1;
$orderItem->sku = $item->productVariant->sku;
$orderItem->price = $item->productVariant->getFinalPrice();      

//Inner transaction 
DB::transaction(function () use ($quantityToDeduct,$productVariantSku) {
$inventory = Inventory::where('sku', $productVariantSku)->where('quantity','>=',$quantityToDeduct)->lockForUpdate()->first();
$inventory->quantity -= $quantityToDeduct;
$inventory->save();
});

$orderItem->save();

});

When the lockForUpdate will be released? When the inner transaction is completed or it will wait for the outer transaction to complete?