Re: [libvirt PATCH 4/7] qemuSaveImageStartProcess: make it possible to use without header

On Thu, Aug 31, 2023 at 05:43:35PM +0200, Peter Krempa wrote: > On Thu, Aug 31, 2023 at 16:55:03 +0200, Pavel Hrdina wrote: > > When used with internal snapshots there is no header to be used and no > > memory state to be decompressed. > > I didn't yet have a look at the rest, but this made me curious. What are > you actually doing with this with internal snapshots? > > There in fact isn't a save image at all with internal snapshots as the > memory image is stored in the qcow2 image (in a different section than > the data -> thus also the name internal) so I'm not exactly sure what > you are refering to here in the commit message. All of that is correct. In PATCH 6/7 this new function is called from qemuSnapshotRevertActive unconditionally. And it will handle reverting internal and external snapshots and do the correct thing based on what arguments are passed to it. In case of internal snapshots we were calling qemuProcessStart and passing virDomainMomentObj. To avoid code duplication this parameter was introduced in PATCH 3/7 to this new helper so it can start QEMU process when reverting to internal snapshot as well as when reverting to external snapshots.