code: public boolean upgradeLock(LockEntry reader)
  	{
  		try
  		{
  			upgradeLockRemote(reader);
  			reader.setLockType(LockEntry.LOCK_WRITE);
  			return true;
  		}
  		catch (Throwable t)
  		{
  			log.error("Cannot upgrade LockEntry " + reader, t);
  			return false;
  		}
  	}
docs: upgrade a reader lock entry for transaction tx on object obj
  and write it to the persistent storage.