code: public void removeAll(TaskAttemptID taskId) throws IOException {
      String toBeDeleted =
        TaskTracker.getIntermediateOutputDir(jobId.toString(), taskId.toString());
      if (asyncDiskService != null) {
        asyncDiskService.moveAndDeleteFromEachVolume(toBeDeleted);
        LOG.info("Move and then delete map ouput " +
                 toBeDeleted + " for task " + taskId);
        return;
      }
      LOG.info("Delete map ouput " + toBeDeleted + " for task " + taskId);
      conf.deleteLocalFiles(toBeDeleted);
    }
docs: Removes all of the files related to a task.