[PATCH v2 0/7] qemu: implementation of transient disk option

[Masayoshi Mizuma]

This patchset tries to implement transient option for qcow2 and raw
format disk. This uses the snapshot cleanup codes:
https://www.redhat.com/archives/libvir-list/2020-August/msg00299.html

It gets user available to set <transient/> to the domain xml file like as:

    <disk type='file' device='disk'>
      <driver name='qemu' type='qcow2'/>
      <source file='/var/lib/libvirt/images/guest.qcow2'/>
      <target dev='vda' bus='virtio'/>
      <transient/>
    </disk>

Any changes which the Guest does to the disk is dropped when the Guest
is shutdowned.

There are some limitations for transient disk option so far:

- Supported disk format is qcow2 and raw
- blockdev capability is required for qemu
- Following features are blocked with transient disk option
  - blockjobs 
  - Migration
  - Disk hotplug

Masayoshi Mizuma (7):
  qemuSnapshotDiskPrepareOne: Get available even if snapdisk is NULL
  qemu: Introduce functions to handle transient disk
  qemu: Add transient disk handler to start and stop the guest
  qemu: Transient option gets avaiable for qcow2 and raw format disk
  qemu: Block blockjobs when transient disk option is enabled
  qemu: Block migration when transient disk option is enabled
  qemu: Block disk hotplug when transient disk option is enabled

 src/qemu/qemu_domain.c    |   7 ++
 src/qemu/qemu_hotplug.c   |   6 ++
 src/qemu/qemu_migration.c |  22 ++++++
 src/qemu/qemu_process.c   |   8 +++
 src/qemu/qemu_snapshot.c  | 139 +++++++++++++++++++++++++++++++++++++-
 src/qemu/qemu_snapshot.h  |   8 +++
 src/qemu/qemu_validate.c  |   9 ++-
 src/util/virstoragefile.h |   2 +
 8 files changed, 196 insertions(+), 5 deletions(-)

-- 
2.27.0