[ovirt-devel] Re: [storage] how to find if a snapshot is in preview based on storage domain metadata only?

On Fri, Aug 21, 2020 at 4:34 AM Germano Veit Michel <germano(a)redhat.com&gt; wrote: > Hi, > > Is there a reliable way to figure out if a snapshot is in preview only > using information obtained from the storage domain metadata? > I'm trying to find a way to distinguish a problematic snapshot chain > (double parent) from a snapshot in preview in order to improve dump-volume > chains. > > Currently dump-volume-chains throws an error (DuplicateParentError) if a > snapshot is in preview for the image, as there is a 'Y' shape split in the > chain > with 2 volumes (previous chain + preview) pointing to a common parent: > > image: dff0a0c0-b731-4e5b-9f32-d97310ca40de > > Error: more than one volume pointing to the same parent > volume e.g: (_BLANK_UUID<-a), (a<-b), (a<-c) > > Unordered volumes and children: > > - e6c7bec0-53c6-4729-a4a0-a9b3ef2b8c38 <- > 5eb2b29d-82d6-4337-8511-3c86705d566e > status: OK, voltype: LEAF, format: COW, legality: LEGAL, > type: SPARSE, capacity: 1073741824, truesize: 1073741824 > > - e0475853-4514-4464-99e7-b185cce9b67d <- > deceff83-9d88-4f87-8304-d5bf74d119b1 > status: OK, voltype: LEAF, format: COW, legality: LEGAL, > type: SPARSE, capacity: 1073741824, truesize: 1073741824 > > - e6c7bec0-53c6-4729-a4a0-a9b3ef2b8c38 <- > e0475853-4514-4464-99e7-b185cce9b67d > status: OK, voltype: INTERNAL, format: COW, legality: > LEGAL, type: SPARSE, capacity: 1073741824, truesize: 1073741824 > > - 00000000-0000-0000-0000-000000000000 <- > e6c7bec0-53c6-4729-a4a0-a9b3ef2b8c38 > status: OK, voltype: INTERNAL, format: RAW, legality: > LEGAL, type: PREALLOCATED, capacity: 1073741824, truesize: 1073741824 > > From the engine side it's easy, but I'd need to solve this problem using > only metadata from the storage. > > The only thing I could think of is that one of the volumes pointing to > the common parent has voltype LEAF. Any better ideas? > don't think that there is any, Engine is the orchestrator and due to that the info is only in the database