@Override
  protected boolean holdLock(MasterProcedureEnv env) {
    // In order to avoid enabling/disabling/modifying/deleting table during snapshot,
    // we don't release lock during suspend
    return true;
  }
A procedure used to take snapshot on tables.
hbase-server/src/main/java/org/apache/hadoop/hbase/master/procedure/SnapshotProcedure.java