static boolean mkdirs(FileSystem fs, Configuration conf, Path dir) throws IOException {
    if (
      FSUtils.isDistributedFileSystem(fs)
        || !conf.getBoolean(HConstants.ENABLE_DATA_FILE_UMASK, false)
    ) {
      return fs.mkdirs(dir);
    }
    FsPermission perms = CommonFSUtils.getFilePermissions(fs, conf, HConstants.DATA_FILE_UMASK_KEY);
    return fs.mkdirs(dir, perms);
  }
Remove merged region
@param mergedRegion {@link RegionInfo}
hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/HRegionFileSystem.java