code: private Map<File, File> getDataMap(int vcode, String[] dataDirs, String snapshotName) {
  		Map<File, File> map = new HashMap<File, File>();
  
  		Map<File, File[]> src = vcode==0 ? getDataMap_1_0(dataDirs) : getDataMap_1_1(dataDirs);
  		for (File ks : src.keySet()) {
  			File[] sn = src.get(ks);
  
  			if (sn != null) {
  				for (int i = 0; i < sn.length; i++) {
  					if (snapshotName.equals(sn[i].getName())) {
  						map.put(ks, sn[i]);
  						break;
  					}
  				}
  			}
  		}
  
  		return map;
  	}
docs: keyspace-dir -> snapshot-dir