Merge remote-tracking branch 'kevin/tags/for-upstream' into block

Merge remote-tracking branch 'kevin/tags/for-upstream' into block

Block layer patches:

- Fix some jobs/drain/aio_poll related hangs
- commit: Add top-node/base-node options
- linux-aio: Fix locking for qemu_laio_process_completions()
- Fix use after free error in bdrv_open_inherit

# gpg: Signature made Tue Sep 25 15:54:01 2018 CEST
# gpg:                using RSA key 7F09B272C88F2FD6
# gpg: Good signature from "Kevin Wolf <kwolf@redhat.com>"
# Primary key fingerprint: DC3D EB15 9A9A F95D 3D74  56FE 7F09 B272 C88F 2FD6

* kevin/tags/for-upstream: (26 commits)
  test-bdrv-drain: Test draining job source child and parent
  block: Use a single global AioWait
  test-bdrv-drain: Fix outdated comments
  test-bdrv-drain: AIO_WAIT_WHILE() in job .commit/.abort
  job: Avoid deadlocks in job_completed_txn_abort()
  test-bdrv-drain: Test nested poll in bdrv_drain_poll_top_level()
  block: Remove aio_poll() in bdrv_drain_poll variants
  blockjob: Lie better in child_job_drained_poll()
  block-backend: Decrease in_flight only after callback
  block-backend: Fix potential double blk_delete()
  block-backend: Add .drained_poll callback
  block: Add missing locking in bdrv_co_drain_bh_cb()
  test-bdrv-drain: Test AIO_WAIT_WHILE() in completion callback
  job: Use AIO_WAIT_WHILE() in job_finish_sync()
  test-blockjob: Acquire AioContext around job_cancel_sync()
  test-bdrv-drain: Drain with block jobs in an I/O thread
  aio-wait: Increase num_waiters even in home thread
  blockjob: Wake up BDS when job becomes idle
  job: Fix missing locking due to mismerge
  job: Fix nested aio_poll() hanging in job_txn_apply
  ...

Signed-off-by: Max Reitz <mreitz@redhat.com>