When disk name is not specified, it should use the default disk.
They should return max UInt64 for "infinite" virtual filesystems.

**Use case**

ClickHouse cloud.
{
public:
    static constexpr auto name = Impl::name;
    static FunctionPtr create(ContextPtr context)
    {
        return std::make_shared<FilesystemImpl<Impl>>(std::filesystem::space(context->getPath()));
    }
    bool isSuitableForShortCircuitArgumentsExecution(const DataTypesWithConstInfo & ) const override