[PATCH v2 2/2] qemuValidateDomainDeviceDefDiskTransient: Add checking set-action capability

[Peter Krempa]

On Mon, Aug 30, 2021 at 00:30:43 -0400, Masayoshi Mizuma wrote:
> From: Masayoshi Mizuma <m.mizuma at jp.fujitsu.com>
> 
> <transient shareBacking='yes'/> option requires set-action capability
> if destroy action is set to all of the events configuration.
> 
> Signed-off-by: Masayoshi Mizuma <m.mizuma at jp.fujitsu.com>
> ---
>  src/qemu/qemu_validate.c | 13 ++++++++++++-
>  1 file changed, 12 insertions(+), 1 deletion(-)
> 
> diff --git a/src/qemu/qemu_validate.c b/src/qemu/qemu_validate.c
> index 8906aa52d9..0d49512996 100644
> --- a/src/qemu/qemu_validate.c
> +++ b/src/qemu/qemu_validate.c

[...]

> @@ -2991,6 +2992,7 @@ qemuValidateDomainDeviceDefDiskBlkdeviotune(const virDomainDiskDef *disk,
>  
>  static int
>  qemuValidateDomainDeviceDefDiskTransient(const virDomainDiskDef *disk,
> +                                         const virDomainDef *def,
>                                           virQEMUCaps *qemuCaps)
>  
>  {
> @@ -3033,6 +3035,15 @@ qemuValidateDomainDeviceDefDiskTransient(const virDomainDiskDef *disk,
>      }
>  
>      if (disk->transientShareBacking == VIR_TRISTATE_BOOL_YES) {
> +        if (!qemuProcessRebootAllowed(def) &&
> +            !virQEMUCapsGet(qemuCaps, QEMU_CAPS_SET_ACTION)) {
> +            virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
> +                           _("transient disk backing image sharing with destroy action of lifecycle "
> +                             "isn't supported by this QEMU binary (%s)"),
> +                             disk->dst);
> +            return -1;

I didn't really consider this corner case worth worrying about.

I'll exchange the two terms in the condition since I prefer when
capability checks go first in such cases and put the error message on a
single line for easier greppability and also add a better explanation of
the specific scenario this is handling into the commit message.

Series:

Reviewed-by: Peter Krempa <pkrempa at redhat.com>