On Fri, Sep 10, 2021 at 4:35 PM Peter Krempa <pkrempa@xxxxxxxxxx> wrote:
>
> We don't support all startup policies with all source types so to
> correctly allow switching from a 'file' based cdrom with 'optional'
> startup policy to a 'block' based one which doesn't support optional we
> must update the startup policy field first. Obviously we need to have
> fallback if the update fails.
Why is there a difference between file and block for startup policy?
Is this documented?
Do we have a way to switch from file to block with current libvirt
(centos 8 stream, rhel 8.4) without this patch, or do we need to wait
until this fix is available? (rhel 8.5?)
> Reported-by: Vojtech Juranek <vjuranek@xxxxxxxxxx>
> Signed-off-by: Peter Krempa <pkrempa@xxxxxxxxxx>
> ---
> src/qemu/qemu_driver.c | 11 ++++++++++-
> 1 file changed, 10 insertions(+), 1 deletion(-)
>
> diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
> index bd41ddbc3c..dfc27572c4 100644
> --- a/src/qemu/qemu_driver.c
> +++ b/src/qemu/qemu_driver.c
> @@ -7038,6 +7038,7 @@ qemuDomainChangeDiskLive(virDomainObj *vm,
> {
> virDomainDiskDef *disk = dev->data.disk;
> virDomainDiskDef *orig_disk = NULL;
> + virDomainStartupPolicy origStartupPolicy;
> virDomainDeviceDef oldDev = { .type = dev->type };
>
> if (!(orig_disk = virDomainDiskByTarget(vm->def, disk->dst))) {
> @@ -7047,6 +7048,7 @@ qemuDomainChangeDiskLive(virDomainObj *vm,
> }
>
> oldDev.data.disk = orig_disk;
> + origStartupPolicy = orig_disk->startupPolicy;
> if (virDomainDefCompatibleDevice(vm->def, dev, &oldDev,
> VIR_DOMAIN_DEVICE_ACTION_UPDATE,
> true) < 0)
> @@ -7065,13 +7067,20 @@ qemuDomainChangeDiskLive(virDomainObj *vm,
> return -1;
> }
>
> + /* update startup policy first before updating disk image */
> + orig_disk->startupPolicy = dev->data.disk->startupPolicy;
> +
> if (qemuDomainChangeEjectableMedia(driver, vm, orig_disk,
> - dev->data.disk->src, force) < 0)
> + dev->data.disk->src, force) < 0) {
> + /* revert startup policy before failing */
> + orig_disk->startupPolicy = origStartupPolicy;
> return -1;
> + }
>
> dev->data.disk->src = NULL;
> }
>
> + /* in case when we aren't updating disk source we update startup policy here */
> orig_disk->startupPolicy = dev->data.disk->startupPolicy;
> orig_disk->snapshot = dev->data.disk->snapshot;
>
> --
> 2.31.1
>
