public void loadHdfsRegioninfo(Configuration conf) throws IOException {
    Path regionDir = getHdfsRegionDir();
    if (regionDir == null) {
      if (getReplicaId() == RegionInfo.DEFAULT_REPLICA_ID) {
        // Log warning only for default/ primary replica with no region dir
        LOG.warn("No HDFS region dir found: " + this + " meta=" + metaEntry);
      }
      return;
    }

    if (hdfsEntry.hri != null) {
      // already loaded data
      return;
    }

    FileSystem fs = FileSystem.get(conf);
    RegionInfo hri = HRegionFileSystem.loadRegionInfoFileContent(fs, regionDir);
    LOG.debug("RegionInfo read: " + hri.toString());
    hdfsEntry.hri = hri;
  }
Read the .regioninfo file from the file system. If there is no .regioninfo, add it to the
orphan hdfs region list.
hbase-server/src/main/java/org/apache/hadoop/hbase/util/HbckRegionInfo.java