anchor.diff:  handle_append(_Prefix, <<>>, _Csum, _Extra, _FluName) ->
       {error, bad_arg};
   handle_append(Prefix, Chunk, Csum, Extra, FluName) ->
  -    case machi_flu_filename_mgr:find_or_make_filename_from_prefix({prefix, Prefix}) of
  +    Res = machi_flu_filename_mgr:find_or_make_filename_from_prefix(FluName, {prefix, Prefix}),
  +    case Res of
           {file, F} ->
               {ok, Pid} = machi_flu_metadata_mgr:start_proxy_pid(FluName, {file, F}),
  -            {Tag, Csum} = machi_util:unmake_tagged_csum(Csum),
  -            Meta = [{client_csum_tag, Tag}, {client_csum, Csum}],
  +            {Tag, CS} = machi_util:unmake_tagged_csum(Csum),
  +            Meta = [{client_csum_tag, Tag}, {client_csum, CS}],
               machi_file_proxy:append(Pid, Meta, Extra, Chunk);
           Error ->
               Error
  
positive.code:     case machi_flu_metadata_mgr:lookup_proxy_pid(FluName, {file, File}) of
          undefined ->
              ok;
          {ok, Pid} ->
            machi_file_proxy:sync(Pid, csum)
      end.
  
  
negative.code: 
  sanitize_prefix(Prefix) ->
      %% We are using '^' as our component delimiter
      case re:run(Prefix, "/|\\^") of
          nomatch ->
              ok;
          _ ->
  