Re: [Qemu-devel] [PATCH v3 09/10] block: drive_backup transaction callback support

[Max Reitz <mreitz@redhat.com>]

On 23.04.2015 02:04, John Snow wrote:
> This patch actually implements the transactional callback system
> for the drive_backup action.
>
> (1) We manually pick up a reference to the bitmap if present to allow
>      its cleanup to be delayed until after all drive_backup jobs launched
>      by the transaction have fully completed.
>
> (2) We create a functional closure that envelops the original drive_backup
>      callback, to be able to intercept the completion status and return code
>      for the job.
>
> (3) We add the drive_backup_cb method for the drive_backup action, which
>      unpacks the completion information and invokes the final cleanup.
>
> (4) backup_transaction_complete will perform the final cleanup on the
>      backup job.
>
> (5) In the case of transaction cancellation, drive_backup_cb is still
>      responsible for cleaning up the mess we may have already made.
>
> Signed-off-by: John Snow <jsnow@redhat.com>
> ---
>   block/backup.c            |  9 ++++++++
>   blockdev.c                | 53 ++++++++++++++++++++++++++++++++++++++++++++---
>   include/block/block_int.h |  8 +++++++
>   3 files changed, 67 insertions(+), 3 deletions(-)

Reviewed-by: Max Reitz <mreitz@redhat.com>