On 05.02.20 23:45, Eric Blake wrote:
> On 2/4/20 11:08 AM, Max Reitz wrote:
>> Signed-off-by: Max Reitz <mreitz@redhat.com>
> 
> Another sparse commit message (a recurring theme of this series). The
> subject line says 'what', and the patch appears to be faithful to that,
> but if a future bisection lands here, even a one-sentence 'why' would be
> handy; maybe:
> 
> This is part of a larger series of unifying block device relationships
> via child_of_bds.

Sure, works for me.  Or maybe:

Make all parents of backing files pass the appropriate BdrvChildRole.
By doing so, we can switch their BdrvChildClass over to the generic
child_of_bds, which will do the right thing when given a correct
BdrvChildRole.

(Because actually the point of this series is not child_of_bds, but the
BdrvChildRole, which allows the “Deal with filters” series to implement
the child access functions in a more obvious way.  I hope.)

Max