IoGetOplockKeyContextEx

NTSTATUS __fastcall IoGetOplockKeyContextEx(INT64 a1){
  _BYTE *FileObjectExtension; 

  FileObjectExtension = IopGetFileObjectExtension((_FILE_OBJECT *)a1, FoExtTypeOplockKey, 0i64);
  if( !FileObjectExtension || (FileObjectExtension[2] & 3) == 0 )
    LODWORD(FileObjectExtension) = 0;
  return(int)FileObjectExtension;
}

Referenced by:

FsRtlpAttachOplockKey
FsRtlpOplockKeysEqual
FsRtlpOplockStoreKeyForDeleteOperation