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

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(a)redhat.com&gt; > --- Once you fix all of the wrong variable name in this patch as well as in the previous one: