@Override
  public void updateRegionFavoredNodesMapping(String encodedRegionName,
    List<org.apache.hadoop.hbase.shaded.protobuf.generated.HBaseProtos.ServerName> favoredNodes) {
    Address[] addr = new Address[favoredNodes.size()];
    // Refer to the comment on the declaration of regionFavoredNodesMap on why
    // it is a map of region name to Address[]
    for (int i = 0; i < favoredNodes.size(); i++) {
      addr[i] = Address.fromParts(favoredNodes.get(i).getHostName(), favoredNodes.get(i).getPort());
    }
    regionFavoredNodesMap.put(encodedRegionName, addr);
  }
Checks to see if the file system is still accessible. If not, sets abortRequested and
stopRequested
@return false if file system is not available
hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/HRegionServer.java