code: public void shrink(final int iSize) throws IOException {
      final int filledUpTo = getFilledUpTo();
      if (iSize >= filledUpTo)
        return;
  
      OLogManager.instance().debug(this, "Shrinking filled file from " + filledUpTo + " to " + iSize + " bytes. " + toString());
  
      setFilledUpTo(iSize);
    }
docs: /*
  (non-Javadoc)
  
  @see com.orientechnologies.orient.core.storage.fs.OFileAAA#shrink(int)