TODO

o in case of failed transaction correct return code should be set for
  the corresponding operations for msg reply

o ceph_osds_obj_info is an object cache, which contains ->mtime and
  ->size fields (probably other, but for now 2.06.20 it is like that).
  This cache is used to expose an object state between operations in
  a single transaction, for example one operations creates an object,
  the second one inserts new omap entry, the third gets the stat of
  an object, obviously for the second and third operations object
  should already exist and contain valid fields, despite the fact
  that transaction is not yet fully completed.

  Right now modified object in a cache can be seen by other transaction,
  not clear do crimson or legacy osd have this isolation but here
  in Pech it is like that. So probably should be changed in the
  future.

o CEPH_MSG_PING is missing

o In order to support RBD "exclusive-lock" image feature OP_WATCH and
  OP_LIST_WACHERS should be fully implemented. In order to use numjobs>1
  for rbd.fio load image should be created without exclusive-lock, i.e.
  ./bin/rbd create --size 1G rbd/fio_test --image-feature layering

o Crypto is a noop, so cephx should be supported

o make fast crc32c, like original Ceph has