* y/nodefs-cancel:
  Y nodefs: Propagate context to File methods
  fuse: dump WRITE argument in debug logs
  Make pollHack work on read-only mounts
  example: loopback: implement -ro flag
  fs: add TestRoMount
  posixtest: add DirSeek test, Go port of xfstests generic/257
  fs: bridge: implement simple directory seeking
  fs: cleanup after TestForget