bool MMAPV1DatabaseCatalogEntry::isOlderThan24(OperationContext* opCtx) const {
    if (_extentManager->numFiles() == 0)
        return false;

    const DataFileVersion version = _extentManager->getFileFormat(opCtx);
    fassert(40109, version.isCompatibleWithCurrentCode());

    return !version.is24IndexClean();
}
void MMAPV1DatabaseCatalogEntry::markIndexSafe24AndUp(OperationContext* opCtx) {
    if (_extentManager->numFiles() == 0)
        return;

    DataFileVersion version = _extentManager->getFileFormat(opCtx);
    fassert(40110, version.isCompatibleWithCurrentCode());

    if (version.is24IndexClean())
        return;  // nothing to do

    version.setIs24IndexClean();
    _extentManager->setFileFormat(opCtx, version);
}