On Fri, Jun 11, 2021 at 01:21:45PM +0200, Kevin Wolf wrote: > > Did you consider just add a new field? > > > > So, "depth" keeps its meaning "which level provides data". > > > > And we add additional optional field like > > > > absolutely-completely-absent: bool > > > > Which is true if data is nowhere in the backing chain. > > Or how about exposing BDRV_BLOCK_ALLOCATED as 'allocated': 'bool'? Which > I think is what the conclusion was already for NBD, so doing the same in > 'qemu-img map' would be consistent. > > This is, of course, almost the same as 'absolutely-completely-absent', > just without the negating the flag.
If we want to bikeshed on a new name, I think "allocated" is going to cause more confusion than it solves. And "hole" is wrong. Better would be "backing":true for portions of the file that would derive from a backing file, if a backing file had been present. But that still feels like more work than just exposing n+1 in depth. -- Eric Blake, Principal Software Engineer Red Hat, Inc. +1-919-301-3266 Virtualization: qemu.org | libvirt.org
