anchor.diff:  
       % attach external location
       ExternalBlocks = [#file_block{offset = 0, size = 10, file_id = ExternalFileId, storage_id = <<"external_storage_id">>}],
  -    RemoteLocation = #file_location{size = 10, space_uuid = SpaceId,
  +    RemoteLocation = #file_location{size = 10, space_id = SpaceId,
           storage_id = <<"external_storage_id">>, provider_id = ExternalProviderId,
           blocks = ExternalBlocks, file_id = ExternalFileId, uuid = FileUuid,
           version_vector = #{}},
  
positive.code:     {ok, Handle} = lfm_proxy:open(W1, SessionId, {guid, FileGUID}, rdwr),
      ?assertMatch({ok, 10}, lfm_proxy:write(W1, Handle, 0, <<"0123456789">>)),
      ?assertMatch(ok, lfm_proxy:fsync(W1, Handle)),
      RemoteLocation = #file_location{size = 10, space_uuid = SpaceId,
          storage_id = <<"external_storage_id">>, provider_id = ExternalProviderId,
          blocks = ExternalBlocks, file_id = ExternalFileId, uuid = FileUuid,
          version_vector = #{}},
  
negative.code:         rpc:call(W1, fslogic_utils, get_local_file_location, [{uuid, FileUuid}]),
      ExternalBlocks = [#file_block{offset = 1, size = 1}, #file_block{offset = 5, size = 1}],
      ExternalSize = 8,
      RemoteLocation = #file_location{size = ExternalSize, space_id = SpaceId,
          storage_id = <<"external_storage_id">>, provider_id = ExternalProviderId,
          blocks = ExternalBlocks, file_id = ExternalFileId, uuid = FileUuid,
          version_vector = VVLocal, recent_changes = {[], []}},
  