This implements virDomainRevertToSnapshot to work with external
snapshots. In addition it modifies virDomainSnapshotDelete to work
correctly when we revert to non-leaf snapshot or when there is
non-linear snapshot tree with multiple branches.

Gitlab repo with the patches:
https://gitlab.com/phrdina/libvirt/-/tree/snapshot-revert-external

Pavel Hrdina (24):
  libvirt_private: list virDomainMomentDefPostParse
  snapshot_conf: export virDomainSnapshotDiskDefClear
  snapshot_conf: use alternate domain definition in
    virDomainSnapshotDefAssignExternalNames
  snapshot_conf: introduce <revertDisks> metadata element
  snapshot_conf: add new argument to virDomainSnapshotAlignDisks
  qemu_snapshot: introduce qemuSnapshotDomainDefUpdateDisk
  qemu_snapshot: use virDomainDiskByName while updating domain def
  qemu_snapshot: introduce qemuSnapshotCreateQcow2Files
  qemu_snapshot: allow using alternate domain definition when creating
    qcow2 files
  qemu_snapshot: move external disk prepare to single function
  qemu_snapshot: use VIR_ASYNC_JOB_SNAPSHOT when reverting snapshot
  qemu_snapshot: introduce external snapshot revert support
  qemu_snapshot: rename qemuSnapshotDeleteExternalPrepare
  qemu_snapshot: extract external snapshot delete prepare to function
  qemu_snapshot: add merge to external snapshot delete prepare data
  qemu_snapshot: prepare data for non-active leaf external snapshot
    deletion
  qemu_snapshot: add support to delete external snapshot without block
    commit
  qemu_snapshot: delete: properly update parent snapshot with revert
    data
  qemu_snapshot: remove revertdisks when creating new snapshot
  virdomainmomentobjlist: introduce virDomainMomentIsAncestor
  qemu_snapshot: update backing store after deleting external snapshot
  qemu_snapshot: check only once if snapshot is external
  qemu_snapshot: add checks for external snapshot deletion
  qemu_snapshot: allow snapshot revert for external snapshots

 src/conf/schemas/domainsnapshot.rng |   7 +
 src/conf/snapshot_conf.c            |  52 +-
 src/conf/snapshot_conf.h            |  11 +-
 src/conf/virdomainmomentobjlist.c   |  17 +
 src/conf/virdomainmomentobjlist.h   |   4 +
 src/libvirt_private.syms            |   6 +
 src/qemu/qemu_snapshot.c            | 874 ++++++++++++++++++++++------
 src/test/test_driver.c              |   2 +-
 8 files changed, 780 insertions(+), 193 deletions(-)

-- 
2.41.0