Re: [Qemu-devel] [PATCH v5 16/16] blockdev: document transactional shortcomings

[Jeff Cody <jcody@redhat.com>]

On Thu, Sep 06, 2018 at 09:02:25AM -0400, John Snow wrote:
> Presently only the backup job really guarantees what one would consider
> transactional semantics. To guard against someone helpfully adding them
> in the future, document that there are shortcomings in the model that
> would need to be audited at that time.
> 
> Signed-off-by: John Snow <jsnow@redhat.com>

Reviewed-by: Jeff Cody <jcody@redhat.com>

> ---
>  blockdev.c | 8 +++++++-
>  1 file changed, 7 insertions(+), 1 deletion(-)
> 
> diff --git a/blockdev.c b/blockdev.c
> index 0cf8febe6c..d4b42403df 100644
> --- a/blockdev.c
> +++ b/blockdev.c
> @@ -2182,7 +2182,13 @@ static const BlkActionOps actions[] = {
>          .instance_size = sizeof(BlockDirtyBitmapState),
>          .prepare = block_dirty_bitmap_disable_prepare,
>          .abort = block_dirty_bitmap_disable_abort,
> -     }
> +    },
> +    /* Where are transactions for MIRROR, COMMIT and STREAM?
> +     * Although these blockjobs use transaction callbacks like the backup job,
> +     * these jobs do not necessarily adhere to transaction semantics.
> +     * These jobs may not fully undo all of their actions on abort, nor do they
> +     * necessarily work in transactions with more than one job in them.
> +     */
>  };
>  
>  /**
> -- 
> 2.14.4
>