private void reportUnrecognizedDirs() {
    File[] dirs = new File(disk.getMountPath()).listFiles(File::isDirectory);
    if (dirs == null) {
      metrics.diskMountPathFailures.inc();
      logger.warn("Could not list the directories in {}", disk.getMountPath());
    } else {
      for (File dir : dirs) {
        String absPath = dir.getAbsolutePath();
        if (!expectedDirs.contains(absPath)) {
          unexpectedDirs.add(absPath);
        }
      }
      if (unexpectedDirs.size() > 0) {
        logger.warn("Encountered unexpected dirs in {} : {}", disk.getMountPath(), unexpectedDirs);
        metrics.registerUnexpectedDirsForMountPath(disk.getMountPath(), unexpectedDirs.size());
      }
    }
  }
Reports any unrecognized directories on disk
store dir and return swap segment to reserve pool if needed.
ambry-store/src/main/java/com/github/ambry/store/DiskManager.java