On Tue 20 Oct 2020 10:23:33 AM CEST, Kevin Wolf wrote: >> > https://lists.gnu.org/archive/html/qemu-block/2020-02/msg00601.html >> >> I forgot to add, we still don't support changing bs->file with this >> command, so I guess that would be one blocker? >> >> There's no other way of inserting filter nodes, or is there? > > Not that I'm aware of. > > So yes, changing bs->file is the one thing I had in mind for > implementing before we mark it stable.
Note that you can still open a new bs with a different bs->file and replace the original one (as long as the original one is the backing file of an existing bs, that is :)). > I'm not entirely sure if we should make some restrictions or allow > arbitrary changes. If it's only about filters, we could check that the > node returned by bdrv_skip_filters() stays the same. This would be > almost certainly safe (if the chain is not frozen, of course). > > If people want to dynamically insert non-filters (maybe quorum?), it > might be more restrictive than necessary, though. You mean replacing bs->file with a Quorum node? Quorum itself does not use bs->file, it has the 'children' attribute. Berto
