[libvirt] [PATCH] qemu: Fix regression in snapshot-revert

[Daniel Henrique Barboza]

On 9/9/19 5:52 PM, Eric Blake wrote:
> Commit f10562799 introduced a regression: if reverting to a snapshot
> fails early (such as when we refuse to revert to an external
> snapshot), we lose track of the domain's current snapshot.
>
> See: https://bugzilla.redhat.com/1738747
> Signed-off-by: Eric Blake <eblake at redhat.com>
> ---

I don't understand why f10562799 broke this code like this - tried
looking the changes made in the commit and the "if (snap)" was
there since a long time, no changes were made in the 'snap'
variable as well - but this change didn't break anything else, so:

Reviewed-by: Daniel Henrique Barboza <danielhb413 at gmail.com>


ps: I think adding a test case for this failure (in tests/virsh-snapshot ?)
is worth considering, especially considering that we changes from
from Maxiwell (adding an inactive XML to the snapshot) that can
add up more complexity in the snapshot mechanics.


Thanks,


DHB


>   src/qemu/qemu_driver.c | 2 --
>   1 file changed, 2 deletions(-)
>
> diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
> index b28a26c3d6..093b15f500 100644
> --- a/src/qemu/qemu_driver.c
> +++ b/src/qemu/qemu_driver.c
> @@ -16941,8 +16941,6 @@ qemuDomainRevertToSnapshot(virDomainSnapshotPtr snapshot,
>               virDomainSnapshotSetCurrent(vm->snapshots, NULL);
>               ret = -1;
>           }
> -    } else if (snap) {
> -        virDomainSnapshotSetCurrent(vm->snapshots, NULL);
>       }
>       if (ret == 0 && config && vm->persistent &&
>           !(ret = virDomainSaveConfig(cfg->configDir, driver->caps,