RFC x-blockdev-create for qcow2

This series implements a minimal QMP command that allows to create an image format on a given block node. The interface is still going to change to some kind of an async command (possibly a block job), so I prefixed x- for now.

At this point, I'm mostly interested in comments about BlockdevCreateOptions in the schema, the .bdrv_co_create callback and the way that legacy .bdrv_create is implemented in qcow2 now.

It looks to me as if we will have to keep .bdrv_create in addition to the new .bdrv_co_create for a while in all drivers, where the implementation of .bdrv_create would call .bdrv_co_create like this series does it for qcow2. We'll only be able to drop the old interface after deprecating and eventually removing all of the driver-specific compatibility work that remains. The example of qcow2 shows that the "translation" from old to new is managable, but there are a few differences.

Kevin Wolf (10):
block/qapi: Introduce BlockdevCreateOptions block/qapi: Add qcow2 create options to schema
qcow2: Let qcow2_create() handle protocol layer
qcow2: Pass BlockdevCreateOptions to qcow2_create2()
qcow2: Use BlockdevRef in qcow2_create2()
qcow2: Use QCryptoBlockCreateOptions in qcow2_create2()
qcow2: Handle full/falloc preallocation in qcow2_create2()
util: Add qemu_opts_to_qdict_filtered()
qcow2: Use visitor for options in qcow2_create()
block: x-blockdev-create QMP command

 qapi/block-core.json       | 107 ++++++++++++
 include/block/block.h      |   1 +
 include/block/block_int.h  |   2 +
 include/qemu/option.h      |   2 +
 block.c                    |  87 ++++++++++
 block/qcow2.c              | 395 +++++++++++++++++++++++++++++----------------
 util/qemu-option.c         |  28 +++-
 tests/qemu-iotests/049.out |  10 +-
 8 files changed, 486 insertions(+), 146 deletions(-)

2.13.6