[libvirt] [PATCH] domain: Fix migratable XML with graphics/@listen

[Peter Krempa]

On Wed, Sep 23, 2015 at 22:48:14 +0200, Jiri Denemark wrote:
> As of commit 6992994, we set graphics/@listen attribute according to the
> first listen child element even if that element is of type='network'.
> This was done for backward compatibility with applications which only
> support the original listen attribute. However, by doing so we broke
> migration to older libvirt which tried to check that the listen
> attribute matches one of the listen child elements but which did not
> take type='network' elements into account.
> 
> We are not concerned about compatibility with old applications when
> formatting domain XML for migration for two reasons. The XML is consumed
> only by libvirtd and the IP address associated with type='network'
> listen address on the source host is just useless on the destination
> host. Thus, we can safely avoid propagating the type='network' IP
> address to graphics/@listen attribute when creating migratable XML.
> 
> https://bugzilla.redhat.com/show_bug.cgi?id=1265111
> 
> Signed-off-by: Jiri Denemark <jdenemar at redhat.com>
> ---
>  src/conf/domain_conf.c | 16 +++++++---------
>  1 file changed, 7 insertions(+), 9 deletions(-)
> 
> diff --git a/src/conf/domain_conf.c b/src/conf/domain_conf.c
> index c890977..033ae46 100644
> --- a/src/conf/domain_conf.c
> +++ b/src/conf/domain_conf.c
> @@ -21020,19 +21020,17 @@ virDomainGraphicsDefFormat(virBufferPtr buf,
>      * <graphics>. This is done to improve backward compatibility.
>      */
>      for (i = 0; i < def->nListens; i++) {
> -        virDomainGraphicsListenType listenType;
> -
>          if (flags & VIR_DOMAIN_DEF_FORMAT_MIGRATABLE &&
>              def->listens[i].fromConfig)
>              continue;
> -        listenType = virDomainGraphicsListenGetType(def, i);
>  
> -        if (listenType == VIR_DOMAIN_GRAPHICS_LISTEN_TYPE_ADDRESS ||
> -            (listenType == VIR_DOMAIN_GRAPHICS_LISTEN_TYPE_NETWORK &&
> -             !(flags & VIR_DOMAIN_DEF_FORMAT_INACTIVE))) {
> -            if ((listenAddr = virDomainGraphicsListenGetAddress(def, i)))
> -                break;
> -        }
> +        if (def->listens[i].type == VIR_DOMAIN_GRAPHICS_LISTEN_TYPE_NETWORK &&
> +            flags & (VIR_DOMAIN_DEF_FORMAT_INACTIVE |
> +                     VIR_DOMAIN_DEF_FORMAT_MIGRATABLE))

So basically the above line is the only functional change in the whole
refactor.

> +            continue;
> +
> +        if ((listenAddr = virDomainGraphicsListenGetAddress(def, i)))
> +            break;
>      }
>  
>      virBufferAsprintf(buf, "<graphics type='%s'", type);

ACK, but the change wasn't easy to interpret correctly.

Peter
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