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

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(a)redhat.com&gt; ---