Hi,

This is a new (very small) block job that writes a pattern into a
bitmap. The only pattern implemented is the top allocation information.

This can be used to "recover" an incremental bitmap chain if an external
snapshot was taken without creating a new bitmap first: any writes made
to the image will be reflected by the allocation status and can be
written back into a bitmap.

This is useful for e.g. libvirt managing backup chains if a user creates
an external snapshot outside of libvirt.

Patches 1-2: The new job.
Patch 3: iotest prerequisite
Patch 4-5: completely optional cleanup.
Patch 6: Test.

John Snow (6):
  block: add bitmap-populate job
  qmp: expose block-dirty-bitmap-populate
  iotests: move bitmap helpers into their own file
  iotests: add hmp helper with logging
  qmp.py: change event_wait to use a dict
  iotests: add 287 for block-dirty-bitmap-populate

 qapi/block-core.json          |   66 +
 qapi/job.json                 |    2 +-
 qapi/transaction.json         |    2 +
 include/block/block_int.h     |   21 +
 block/bitmap-alloc.c          |  207 ++
 blockdev.c                    |   78 +
 blockjob.c                    |    3 +-
 block/Makefile.objs           |    1 +
 python/qemu/machine.py        |   10 +-
 tests/qemu-iotests/040        |   12 +-
 tests/qemu-iotests/257        |  110 +-
 tests/qemu-iotests/260        |    5 +-
 tests/qemu-iotests/287        |  233 ++
 tests/qemu-iotests/287.out    | 4544 +++++++++++++++++++++++++++++++++
 tests/qemu-iotests/bitmaps.py |  131 +
 tests/qemu-iotests/group      |    1 +
 tests/qemu-iotests/iotests.py |   34 +-
 17 files changed, 5321 insertions(+), 139 deletions(-)
 create mode 100644 block/bitmap-alloc.c
 create mode 100755 tests/qemu-iotests/287
 create mode 100644 tests/qemu-iotests/287.out
 create mode 100644 tests/qemu-iotests/bitmaps.py

-- 
2.21.1