See GetRtFileInfoByHandle

typedef struct tagFileInfoId {
        QWORD           qwVolumeId;
        QWORD           qwFileIdLow;
        QWORD           qwFileIdHigh;
} FILE_INFO_ID;

Fields

qwVolumeId

The serial number of the volume which contains the file.

qwFileIdLow

Unique file ID number for the file (low 64 bits).

qwFileIdHigh

Unique file ID number for the file (high 64 bits).