Re: [libvirt] [PATCH] qemu: Warn of restore with managed save being risky
On 12/30/19 3:07 PM, Michael Weiser wrote:
Internal snapshots of a non-running domain do not carry any memory
state
and restoring such a snapshot will not replace existing saved memory
state. This allows a scenario, where a user first suspends a domain into
managedsave, restores a non-running snapshot and then resumes the domain
from managedsave. After that, the guest system will run with its
previous memory state atop a different disk state. The most obvious
possible fallout from this is extensive file system corruption. Swap
content and RAID bitmaps might also be off.
This has been discussed[1] and fixed[2] from the end-user perspective for
virt-manager.
This patch marks the restore operation as risky at the libvirt level,
requiring the user to remove the saved memory state first or force the
operation.
[1] https://www.redhat.com/archives/virt-tools-list/2019-November/msg00011.html
[2] https://www.redhat.com/archives/virt-tools-list/2019-December/msg00049.html
Signed-off-by: Michael Weiser <michael.weiser(a)gmx.de>
Cc: Cole Robinson <crobinso(a)redhat.com>
---
As said in [1], I agree that the API needs a flag override to allow the user
to roll with it despite the risks. Given that this is somewhat a corner case,
I also believe that such override can go in a separated patch/series later
on.
Reviewed-by: Daniel Henrique Barboza <danielhb413(a)gmail.com>