anchor.diff:  update_vnode_status(F, Index) ->
       VnodeFile = vnode_status_filename(Index),
       ok = filelib:ensure_dir(VnodeFile),
  -    case read_vnode_status(VnodeFile) of
  -        {ok, Status} ->
  -            update_vnode_status2(F, Status, VnodeFile);
  -        {error, enoent} ->
  -            update_vnode_status2(F, [], VnodeFile);
  -        ER ->
  -            ER
  -    end.
  +    {ok, Status} = read_vnode_status(VnodeFile),
  +    update_vnode_status2(F, Status, VnodeFile).
   
   update_vnode_status2(F, Status, VnodeFile) ->
       case F(Status) of
  
positive.code:     filename:join(VnodeStatusDir, integer_to_list(Index)).
  
  read_vnode_status(File) ->
      case file:consult(File) of
          {ok, [Status]} when is_list(Status) ->
              {ok, proplists:delete(version, Status)};
          ER ->
              ER
      end.
  
  write_vnode_status(Status, File) ->
  
negative.code:       ?_test(begin % update failure
                   ?cmd("chmod 000 kv_vnode_status_test/0"),
                   ?cmd("chmod 500 kv_vnode_status_test"),
                   F = fun([]) ->
                               {shouldfail, [updatedagain]}
                       end,
                   Index = 0,
  