protected CatalogJanitorReport scanForReport() throws IOException {
    ReportMakingVisitor visitor = new ReportMakingVisitor(this.services);
    // Null tablename means scan all of meta.
    MetaTableAccessor.scanMetaForTableRegions(this.services.getConnection(), visitor, null);
    return visitor.getReport();
  }
Scan hbase:meta.
@return Return generated {@link CatalogJanitorReport}
hbase-server/src/main/java/org/apache/hadoop/hbase/master/janitor/CatalogJanitor.java