@Override
  protected boolean downgradeToSharedTableLock() {
    // for taking snapshot on disabled table, it is OK to always hold the exclusive lock, as we do
    // not need to assign the regions when there are region server crashes.
    return false;
  }
@param snapshot       descriptor of the snapshot to take
@param masterServices master services provider
@throws IOException if it cannot access the filesystem of the snapshot temporary directory
hbase-server/src/main/java/org/apache/hadoop/hbase/master/snapshot/DisabledTableSnapshotHandler.java