Re: [Qemu-devel] [PATCH V6 0/3] Implement sync modes for drive-backup.

[Stefan Hajnoczi]

On Mon, Jul 22, 2013 at 03:09:17PM -0700, Ian Main wrote:
> This patch adds sync modes on top of the work that Stefan Hajnoczi has done.
> 
> These patches apply on kevin/block.
> 
> Hopefully all is in order as this is my first QEMU patch.  Many thanks to
> Stephan and Fam Zheng for their help.
> 
> V2:
> 
> - No longer poll, instead use qemu_coroutine_yield().
> - Use bdrv_co_is_allocated().
> - Much better SYNC_MODE_NONE test.
> 
> V3:
> 
> - A few style fixes.
> - Better commit message explaining how TOP and NONE operate.
> - Verified using checkpatch.pl.
> 
> V4:
> 
> - Add patch to use the source as a backing hd during backup.
> - Add patch to default sync mode none to qcow2.
> 
> V5:
> 
> - Fix qcow2 patch.  Forgot to git add final version.
> 
> V6:
> 
> - Default to requiring 'format' when mode is absolute-paths.
> - Removed one bad hunk that was misapplying.
> - Fixed docs, examples and tests to match changes.
> - Added tests for format bad/missing.
> - Added bdrv_set_in_use() to target.
> - Default to qcow2 patch not required.
> 
> Ian Main (3):
>   Implement sync modes for drive-backup.
>   Add tests for sync modes 'TOP' and 'NONE'
>   Add backing drive while performing backup.
> 
>  block/backup.c                | 107 +++++++++++++++++++++++++++++------------
>  blockdev.c                    |  36 +++++++++-----
>  include/block/block_int.h     |   4 +-
>  qapi-schema.json              |   4 +-
>  qmp-commands.hx               |   2 +
>  tests/qemu-iotests/055        | 108 
> +++++++++++++++++++++++++++++++++++++-----
>  tests/qemu-iotests/055.out    |   4 +-
>  tests/qemu-iotests/group      |   2 +-
>  tests/qemu-iotests/iotests.py |   5 ++
>  9 files changed, 211 insertions(+), 61 deletions(-)

This patch mostly takes care of image fleecing except it does not give
the target a device name which can be used by nbd-server-add.

Fam's series tackles the target device name and some of the overlapping
problems with your series.

The core feature in your series is sync=top|none and that needs to be
merged.

Now we need to figure out which patches to take and what must be
changed.  Please see the sub-threads on Fam's series.  Perhaps we can
reach a consensus there.

Stefan