anchor.diff:  %%% O3) Remove orphaned blobs
   %%%
   -spec delete_orphaned(pid(), disco_util:timestamp(), nonempty_string(),
  -                      nonempty_string(), 'blob'|'tag', non_neg_integer()) -> _.
  +                      mode(), tabname(), non_neg_integer()) -> 'ok'.
   delete_orphaned(Master, Now, Root, Mode, Ets, Expires) ->
       Paranoid = disco:has_setting("DDFS_PARANOID_DELETE"),
       lists:foreach(
  
positive.code:                 delete_if_expired(FullPath, Diff, Expires, Paranoid)
          end, ets:match(Ets, {'$1', '$2', false})).
  
  -spec is_really_orphan(pid(), binary()) -> bool().
  is_really_orphan(Master, Obj) ->
      Master ! {is_orphan, self(), Obj},
      receive
  
negative.code:     end.
  
  -spec delete_if_expired(file:filename(), float(),
                          non_neg_integer(), boolean()) -> 'ok'.
  delete_if_expired(Path, Diff, Expires, true) when Diff > Expires ->
      error_logger:info_report({"GC: Deleting expired object (paranoid)", Path}),
      Trash = "!trash." ++ filename:basename(Path),
  