public static Path getBackupPath(String backupRootDir, String backupId) {
    return new Path(backupRootDir + Path.SEPARATOR + backupId);
  }
Get backup tmp directory for backupId
@param backupRoot backup root
@param backupId   backup id
@return backup tmp directory path
hbase-backup/src/main/java/org/apache/hadoop/hbase/backup/HBackupFileSystem.java