Re: [libvirt] [PATCH] qemu_blockjob: Remove secdriver metadata for whole backing chain on job completion

On Mon, Sep 16, 2019 at 12:34:32 +0200, Michal Privoznik wrote: That depends on the job. In case of the legacy handler both job types which modify which top level image (thus the image which is stored as disk->src will no longer be used after the handler returns) is being used are handled via the "if (disk->mirrorState == VIR_DOMAIN_DISK_MIRROR_STATE_PIVOT) {" code path. That case already handles the top level image where the metadata is transferred, but both block copy and active block commit may remove a chain of images from use. All other cases are handled via the '} else {' branch: In case of block pull, libvirt does not need to modify any permissions as the data is pulled into the top level image directly. In case of (non active layer) block commit (assume the following backing chain for example's sake: #activeimage -> #dummy1 -> #top -> #intermediate1..n -> #base -> #endofchain). Libvirt modifies #dummy1's and #base's permissions to read write. #dummy1 gets the backing store specifier updated and #base gets all the data. Then #top and all #intermediateH images are dropped from the chain. #activeimage stays read-write. This means that we probably shouldn't modify/drop labels for #activeimage (disk->src) as it will be used same way it was. Note that there's still the question of failed cancelled jobs. We still do the relabelling when starting the job and the images are still used, the question is whether it's cleaned up during VM shutdown. disk->src is probably okay to stay as-is.