Merge remote-tracking branch 'kwolf/for-anthony' into staging

Merge remote-tracking branch 'kwolf/for-anthony' into staging

* kwolf/for-anthony: (22 commits)
  scsi: Guard against buflen exceeding req->cmd.xfer in scsi_disk_emulate_command
  qcow: Use bdrv functions to replace file operation
  qcow: Return real error code in qcow_open
  block/vdi: Zero unused parts when allocating a new block (fix #919242)
  virtio-blk: add virtio_blk_handle_read trace event
  docs: describe live block operations
  block: add support for partial streaming
  add QERR_BASE_NOT_FOUND
  block: add bdrv_find_backing_image
  blockdev: make image streaming safe across hotplug
  qmp: add query-block-jobs
  qmp: add block_job_cancel command
  qmp: add block_job_set_speed command
  qmp: add block_stream command
  block: rate-limit streaming operations
  block: add image streaming block job
  block: add BlockJob interface for long-running operations
  block: make copy-on-read a per-request flag
  block: check bdrv_in_use() before blockdev operations
  coroutine: add co_sleep_ns() coroutine sleep function
  ...