fDeviceID
if (st.st_dev != fDeviceID || st.st_ino != fNodeID) {
dev_t fDeviceID;
{ return fDeviceID; }
fDeviceID(deviceID),
dev_t DeviceID() const { return fDeviceID; }
bool IsCustom() const { return fDeviceID < 0; }
dev_t fDeviceID;