code: protected void reportPrimaryCleared(DatanodeID node) {
      if (node != null && shouldUpdateNodes()) {
        if (outStandingReports.remove(node)) {
          LOG.info("Failover: Outstanding reports: " + outStandingReports.size());
        }
      }
    }
docs: Report that the given datanode has cleared the primary.
  It is fully aware of the failover, and it has sent the
  incremental block report.
  
  @param node
  the datanode that has reported