private static extern bool GetFileInformationByHandleEx(IntPtr hFile, FILE_INFO_BY_HANDLE_CLASS infoClass, out FILE_ID_BOTH_DIR_INFO dirInfo, uint dwBufferSize);

http://www.pinvoke.net/default.aspx/Structures/FILE_ID_BOTH_DIR_INFO.html

        var fileStruct = new FILE_ID_BOTH_DIR_INFO();

    private static extern bool GetFileInformationByHandleEx(IntPtr hFile, FILE_INFO_BY_HANDLE_CLASS infoClass, out FILE_ID_BOTH_DIR_INFO dirInfo, uint dwBufferSize);

http://www.pinvoke.net/default.aspx/Structures/FILE_ID_BOTH_DIR_INFO.html

        var fileStruct = new FILE_ID_BOTH_DIR_INFO();

    /// The file system supports open by FileID. For more information, see FILE_ID_BOTH_DIR_INFO.

    private struct FILE_ID_BOTH_DIR_INFO

Structure FILE_ID_BOTH_DIR_INFO