[libvirt] [PATCH 6/6] qemu: process: Don't redetect backing chain on reconnect

[John Ferlan]

On 10/04/2017 07:59 AM, Peter Krempa wrote:
> Skip purging the backing chain and redetecting it when it was not going
> to change during the time we were not present.
> 
> The decision is based on the new flag which records whether there were
> blockjobs running to the status XML.
> ---
>  src/qemu/qemu_process.c | 19 ++++++++++++-------
>  1 file changed, 12 insertions(+), 7 deletions(-)
> 
> diff --git a/src/qemu/qemu_process.c b/src/qemu/qemu_process.c
> index bde3ba462..80d204599 100644
> --- a/src/qemu/qemu_process.c
> +++ b/src/qemu/qemu_process.c
> @@ -6892,13 +6892,18 @@ qemuProcessReconnect(void *opaque)

BTW: I'd support a

    virDomainDiskDefPtr disk = obj->def->disks[i];

right about here too ;-)


>          if (virStorageTranslateDiskSourcePool(conn, obj->def->disks[i]) < 0)
>              goto error;
> 
> -        /* XXX we should be able to restore all data from XML in the future.
> -         * This should be the only place that calls qemuDomainDetermineDiskChain
> -         * with @report_broken == false to guarantee best-effort domain
> -         * reconnect */
> -        if (qemuDomainDetermineDiskChain(driver, obj, obj->def->disks[i],
> -                                         true, false) < 0)
> -            goto error;
> +        /* backing chains need to be refreshed only if they could change */
> +        if (!priv->reconnectNoActiveBlockjobs) {

...or from my previous patch suggestion

    if (priv->NAME != VIR_TRISTATE_BOOL_NO)

Reviewed-by: John Ferlan <jferlan at redhat.com>

John

I can give an R-B on patch 5 depending on your thoughts there. Maybe I'm
missing something in future attractions...


> +            /* This should be the only place that calls
> +             * qemuDomainDetermineDiskChain with @report_broken == false
> +             * to guarantee best-effort domain reconnect */
> +            if (qemuDomainDetermineDiskChain(driver, obj, obj->def->disks[i],
> +                                             true, false) < 0)
> +                goto error;
> +        } else {
> +            VIR_DEBUG("skipping backing chain detection for '%s'",
> +                      obj->def->disks[i]->dst);
> +        }
> 
>          dev.type = VIR_DOMAIN_DEVICE_DISK;
>          dev.data.disk = obj->def->disks[i];
>