[libvirt] [PATCH] macvtap: libvirtd forgot macvtap device name during a shutdown/restart cycle

[Daniel P. Berrange]

On Tue, Nov 02, 2010 at 11:35:44AM -0400, Stefan Berger wrote:
> During a shutdown/restart cycle libvirtd forgot the macvtap device name 
> that it had created on behalf of a VM so that a stale macvtap device 
> remained on the host when the VM terminated. Libvirtd has to actively 
> tear down a macvtap device and it uses its name for identifying which 
> device to tear down.
> 
> The solution is to not blank out the <target dev='...'/> completely, but 
> only blank it out on VMs that are not active. So, if a VM is active, the 
> device name makes it into the XML and is also being parsed. If a VM is 
> not active, the device name is discarded.
> 
> Signed-off-by: Stefan Berger <stefanb at us.ibm.com>
> 
> ---
>  src/conf/domain_conf.c |    5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
> 
> Index: libvirt-acl/src/conf/domain_conf.c
> ===================================================================
> --- libvirt-acl.orig/src/conf/domain_conf.c
> +++ libvirt-acl/src/conf/domain_conf.c
> @@ -2343,7 +2343,8 @@ virDomainNetDefParseXML(virCapsPtr caps,
>          def->data.direct.linkdev = dev;
>          dev = NULL;
> 
> -        VIR_FREE(ifname);
> +        if ((flags & VIR_DOMAIN_XML_INACTIVE))
> +            VIR_FREE(ifname);

The conditional isn't required here - it is already dealt
with earlier on in the file. Just remove the VIR_FREE
completely.

> @@ -5801,6 +5802,8 @@ virDomainNetDefFormat(virBufferPtr buf,
>          virBufferAddLit(buf, "/>\n");
>          virVirtualPortProfileFormat(buf, 
> &def->data.direct.virtPortProfile,
>                                      "      ");
> +        if ((flags & VIR_DOMAIN_XML_INACTIVE))
> +            VIR_FREE(def->ifname);

This seems dubious. Formatting XML should never require
changing 'def' at all.

Daniel.
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