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

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

* kwolf/for-anthony: (43 commits)
  qcow2: Factor out handle_dependencies()
  qcow2: Execute run_dependent_requests() without lock
  qcow2: Enable dirty flag in qcow2_alloc_cluster_link_l2
  qcow2: Allocate l2meta only for cluster allocations
  qcow2: Drop l2meta.cluster_offset
  qcow2: Allocate l2meta dynamically
  qcow2: Introduce Qcow2COWRegion
  qcow2: Round QCowL2Meta.offset down to cluster boundary
  atapi: reset cdrom tray statuses on ide_reset
  qemu-iotests: Test concurrent cluster allocations
  qcow2: Move BLKDBG_EVENT out of the lock
  qemu-io: Add AIO debugging commands
  blkdebug: Implement suspend/resume of AIO requests
  blkdebug: Factor out remove_rule()
  blkdebug: Allow usage without config file
  create new function: qemu_opt_set_number
  use qemu_opts_create_nofail
  introduce qemu_opts_create_nofail function
  qemu-option: qemu_opt_set_bool(): fix code duplication
  qemu-option: qemu_opts_validate(): fix duplicated code
  ...

Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>