FILE_FS_OBJECTID_INFORMATION - NtDoc

Native API online documentation, based on the System Informer (formerly Process Hacker) phnt headers
#ifndef _NTIOAPI_H

typedef struct _FILE_FS_OBJECTID_INFORMATION
{
    UCHAR ObjectId[16];
    union
    {
        struct
        {
            UCHAR BirthVolumeId[16];
            UCHAR BirthObjectId[16];
            UCHAR DomainId[16];
        };
        UCHAR ExtendedInfo[48];
    };
} FILE_FS_OBJECTID_INFORMATION, *PFILE_FS_OBJECTID_INFORMATION;

#endif

View code on GitHub

This structure is documented in Windows Driver Kit.