[libvirt] [PATCH] qemuDomainDiskChangeSupported: Forbid alias change

[Marc Hartmayer]

On Wed, Dec 13, 2017 at 03:30 PM +0100, Michal Privoznik <mprivozn at redhat.com> wrote:
> Since we have user aliases it may happen that users want to
> change it using 'update-device'. Instead of ignoring it silently,
> error out loudly.
>
> Signed-off-by: Michal Privoznik <mprivozn at redhat.com>
> ---
>  src/qemu/qemu_domain.c | 8 ++++++++
>  1 file changed, 8 insertions(+)
>
> diff --git a/src/qemu/qemu_domain.c b/src/qemu/qemu_domain.c
> index 347fc0742..00d6c41c9 100644
> --- a/src/qemu/qemu_domain.c
> +++ b/src/qemu/qemu_domain.c
> @@ -6762,6 +6762,14 @@ qemuDomainDiskChangeSupported(virDomainDiskDefPtr disk,
>          return false;
>      }
>
> +    if (disk->info.alias &&
> +        STRNEQ_NULLABLE(disk->info.alias, orig_disk->info.alias)) {
> +        virReportError(VIR_ERR_OPERATION_UNSUPPORTED,
> +                       _("cannot modify field '%s' of the disk"),
> +                       "alias");
> +        return false;
> +    }
> +
>      CHECK_EQ(info.bootIndex, "boot order", true);
>      CHECK_EQ(rawio, "rawio", true);
>      CHECK_EQ(sgio, "sgio", true);
> --
> 2.13.6
>
> --
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>

I'm not sure if our current approach is the way to go… Couldn’t we just
invert the logic for qemuDomainDiskChangeSupported in that way that it
returns by default false and only for cases where we know that it’s
supported to change we return true? Not sure if this proposed approach
is feasible.

--
Beste Grüße / Kind regards
   Marc Hartmayer

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