code: static FileSystem getFs(Configuration conf, Path p) {
      try {
        return p.getFileSystem(conf);
      } catch (Exception e) {
        // if a single namenode is down, log it and ignore. Continue to
        // fix other namenodes.
        LOG.warn("getFs: Unable to contact filesystem: " + p + " ignoring.... " +
                 e);
        e.printStackTrace();
        return null;
      }
    }
docs: /*
  returns the FileSystem of the path. If the FileSystem is down, then
  log an error and return null