files_hash_set.add(fileHash);
// load shared completed files
try {
KnownMet known_met = new KnownMet(knownFilePath);
known_file_list = known_met.loadFile();
known_met.close();
} catch (Throwable e) {
e.printStackTrace();
known_file_list = new Hashtable<String, KnownMetEntity>();
}