Re: [Qemu-devel] [PATCH v2 00/16] block: Make blockdev-create a job and stable API

[Jeff Cody <jcody@redhat.com>]

On Tue, May 29, 2018 at 10:38:54PM +0200, Kevin Wolf wrote:
> This changes the x-blockdev-create QMP command so that it doesn't block
> the monitor and the main loop any more, but starts a background job that
> performs the image creation.
> 

I'm sure modifying the drivers is fodder for a future series, since this
series lays the groundwork.  But from testing, some image formats (e.g.
qcow2) still block the main loop and monitor when doing blockdev-create
(preallocation:full, and a larger image size is particularly noticeable).

> The basic job as implemented here is all that is necessary to make image
> creation asynchronous and to provide a QMP interface that can be marked
> stable, but it still lacks a few features that jobs usually provide: The
> job will ignore pause commands and it doesn't publish progress yet (so
> both current-progress and total-progress stay at 0). These features can
> be added later without breaking compatibility.
> 
> At the end of the series, the interface is declared stable and the x-
> prefix is removed.
> 
> v2:
> - Made job->error == NULL iff job->ret == 0 [Max]
> - Fixed a comment in qmp_blockdev_create() and added a TODO comment for
>   AioContext locking at least [Max]
> - Many small changes in the tests [Max, Jeff]
> 
> Kevin Wolf (16):
>   vdi: Fix vdi_co_do_create() return value
>   vhdx: Fix vhdx_co_create() return value
>   job: Add error message for failing jobs
>   block/create: Make x-blockdev-create a job
>   qemu-iotests: Add VM.get_qmp_events_filtered()
>   qemu-iotests: Add VM.qmp_log()
>   qemu-iotests: Add iotests.img_info_log()
>   qemu-iotests: Add VM.run_job()
>   qemu-iotests: iotests.py helper for non-file protocols
>   qemu-iotests: Rewrite 206 for blockdev-create job
>   qemu-iotests: Rewrite 207 for blockdev-create job
>   qemu-iotests: Rewrite 210 for blockdev-create job
>   qemu-iotests: Rewrite 211 for blockdev-create job
>   qemu-iotests: Rewrite 212 for blockdev-create job
>   qemu-iotests: Rewrite 213 for blockdev-create job
>   block/create: Mark blockdev-create stable
> 
>  qapi/block-core.json          |  18 +-
>  qapi/job.json                 |   4 +-
>  include/qemu/job.h            |   7 +-
>  block/backup.c                |   2 +-
>  block/commit.c                |   2 +-
>  block/create.c                |  67 +++--
>  block/mirror.c                |   2 +-
>  block/stream.c                |   2 +-
>  block/vdi.c                   |   1 +
>  block/vhdx.c                  |   2 +-
>  job-qmp.c                     |   9 +-
>  job.c                         |  16 +-
>  tests/test-bdrv-drain.c       |   2 +-
>  tests/test-blockjob-txn.c     |   2 +-
>  tests/test-blockjob.c         |   2 +-
>  tests/qemu-iotests/206        | 680 ++++++++++++++++--------------------------
>  tests/qemu-iotests/206.out    | 253 +++++++++-------
>  tests/qemu-iotests/207        | 440 ++++++++++++---------------
>  tests/qemu-iotests/207.out    | 107 +++----
>  tests/qemu-iotests/210        | 393 ++++++++++--------------
>  tests/qemu-iotests/210.out    | 197 ++++++++----
>  tests/qemu-iotests/211        | 381 ++++++++++-------------
>  tests/qemu-iotests/211.out    | 133 +++++----
>  tests/qemu-iotests/212        | 483 +++++++++++-------------------
>  tests/qemu-iotests/212.out    | 191 +++++++-----
>  tests/qemu-iotests/213        | 520 ++++++++++++--------------------
>  tests/qemu-iotests/213.out    | 208 ++++++++-----
>  tests/qemu-iotests/iotests.py |  78 +++++
>  28 files changed, 1979 insertions(+), 2223 deletions(-)
> 
> -- 
> 2.13.6
>