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

Block layer patches:

- block: AioContext management, part 2
- Avoid recursive block_status call (i.e. lseek() calls) if possible
- linux-aio: Drop unused BlockAIOCB submission method
- nvme: add Get/Set Feature Timestamp support
- Fix crash on commit job start with active I/O on base node
- Fix crash in bdrv_drained_end
- Fix integer overflow in qcow2 discard

# gpg: Signature made Tue 04 Jun 2019 16:20:02 BST
# gpg:                using RSA key 7F09B272C88F2FD6
# gpg: Good signature from "Kevin Wolf <kwolf@redhat.com>" [full]
# Primary key fingerprint: DC3D EB15 9A9A F95D 3D74  56FE 7F09 B272 C88F 2FD6

* remotes/kevin/tags/for-upstream: (29 commits)
  iotests: Fix duplicated diff output on failure
  iotests: test big qcow2 shrink
  block/io: bdrv_pdiscard: support int64_t bytes parameter
  block/qcow2-refcount: add trace-point to qcow2_process_discards
  block: Remove bdrv_set_aio_context()
  test-bdrv-drain: Use bdrv_try_set_aio_context()
  iotests: Attach new devices to node in non-default iothread
  virtio-scsi-test: Test attaching new overlay with iothreads
  block: Remove wrong bdrv_set_aio_context() calls
  blockdev: Use bdrv_try_set_aio_context() for monitor commands
  block: Move node without parents to main AioContext
  test-block-iothread: BlockBackend AioContext across root node change
  test-block-iothread: Test adding parent to iothread node
  block: Adjust AioContexts when attaching nodes
  scsi-disk: Use qdev_prop_drive_iothread
  block: Add qdev_prop_drive_iothread property type
  block: Add BlockBackend.ctx
  block: Add Error to blk_set_aio_context()
  nbd-server: Call blk_set_allow_aio_context_change()
  test-block-iothread: Check filter node in test_propagate_mirror
  ...

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>