[PATCH v2 2/2] qemu: Tell secdrivers which images are top parent

[Peter Krempa]

On Mon, Mar 09, 2020 at 09:29:43 +0100, Michal Privoznik wrote:
> When preparing images for block jobs we modify their seclabels so
> that QEMU can open them. However, as mentioned in the previous
> commit, secdrivers base some it their decisions whether the image
> they are working on is top of of the backing chain. Fortunately,
> in places where we call secdrivers we know this and the
> information can be passed to secdrivers.
> 
> The problem is the following: after the first blockcommit from
> the base to one of the parents the XATTRs on the base image are
> not cleared and therefore the second attempt to do another
> blockcommit fails. This is caused by blockcommit code calling
> qemuSecuritySetImageLabel() over the base image, possibly
> multiple times (to ensure RW/RO access). A naive fix would be to
> call the restore function. But this is not possible, because that
> would deny QEMU the access to the base image.  Fortunately, we
> can use the fact that seclabels are remembered only for the top
> of the backing chain and not for the rest of the backing chain.
> And thanks to the previous commit we can tell secdrivers which
> images are top of the backing chain.
> 
> Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1803551
> 
> Signed-off-by: Michal Privoznik <mprivozn at redhat.com>
> ---

Once you fix all of the wrong variable name in this patch as well as in
the previous one:

Reviewed-by: Peter Krempa <pkrempa at redhat.com>

On both.