[libvirt] [PATCH 0/7] Keep non-persistent changes alive in snapshot

[Scott Garfinkle]

On Mon, 2017-10-30 at 14:21 +0530, Kothapally Madhu Pavan wrote:
> Restoring to a snapshot should not overwrite the persistent XML
> configuration
> of a snapshot as a side effect. This patchset fixes the same.
> Currently,
> virDomainSnapshotDef only saves active domain definition of the
> guest.
> And on restore the active domain definition is used as both active
> and
> inactive domain definitions. This will make the non-persistent
> changes
> persistent in snapshot image. This patchset allows to save inactive
> domain
> definition as well and on snapshot-revert non-persistent
> configuration is
> restored as is.
> 
> Currently, snapshot-revert is making non-presistent changes as
> persistent.
> Here are the steps to reproduce.
> Step1: virsh define $dom
> Step2: virsh attach-device $dom $memory-device.xml --live
> Step3: virsh snapshot-create $dom
> Step4: virsh destroy $dom
> Step5: virsh snapshot-revert $dom $snapshot-name
> Step6: virsh destroy $dom
> Step7: virsh start $dom
> Here we still have $memory-device attached in Step2.
> 
> This patchset is attempting to solve this issue. This patchset will
> also
> allow user to dump and edit inactive XML configuration of a snapshot.
> Dumping inactive domain definition of a snapshot is important as
> --redefine uses snapshot-dumpxml output to redefine a snapshot.
> 
> Kothapally Madhu Pavan (7):
>   qemu: Store inactive domain configuration in snapshot
>   qemu: Use active and inactive snapshot configuration on restore
>   conf: Allow editing inactive snapshot configuration
>   virsh: Dump inactive XML configuration of snapshot using
>     snapshot-dumpxml
>   virsh: Edit inactive XML configuration of snapshot using snapshot-
> edit
>   virsh: Allow restoring snapshot with non-persistent configuration
>   tests: docs: Add schema and testcase for domainsnapshot
> 
>  docs/schemas/domainsnapshot.rng                    | 19 +++++
>  include/libvirt/libvirt-domain-snapshot.h          | 10 ++-
>  include/libvirt/libvirt-domain.h                   |  1 +
>  src/conf/domain_conf.c                             |  6 +-
>  src/conf/domain_conf.h                             |  2 +
>  src/conf/snapshot_conf.c                           | 48
> ++++++++++++-
>  src/conf/snapshot_conf.h                           |  1 +
>  src/qemu/qemu_driver.c                             | 33 ++++++++-
>  .../full_domain_withinactive.xml                   | 83
> ++++++++++++++++++++++
>  tests/domainsnapshotxml2xmltest.c                  |  1 +
>  tools/virsh-snapshot.c                             | 20 ++++++
>  tools/virsh.pod                                    | 37 +++++++++-
>  12 files changed, 251 insertions(+), 10 deletions(-)
>  create mode 100644
> tests/domainsnapshotxml2xmlout/full_domain_withinactive.xml

Could someone please review the patch set? Jiri mentioned in early
December that it was on his list; perhaps this fell through the cracks
or got displaced by the (admittedly more urgent) Spectre/Meltdown
patches.