Re: [PATCH] fix: domains do not get created when using vifname variable for bridged interfaces

[Stefano Stabellini <stefano.stabellini@eu.citrix.com>]

On Mon, 7 Feb 2011, Ian Jackson wrote:
> Patrick Scharrenberg writes ("[Xen-devel] [PATCH] fix: domains do not get created when using vifname variable for bridged interfaces"):
> > In the two scripts vif-bridge and vif-route the variable containing
> > the right interface-name, after an interface was renamed using
> > "ifname", is $vif.  Otherwise hotplug can't handle renamed
> > interfaces and prevents xm from creating domains.
> 
> This seems to be partly reverting 21922:0232bc7c9544 "tools/hotplug,
> Use udev rules instead of qemu script to setup the bridge."
> 
> I can't exactly follow the logic of 21922 but it seems to me that the
> bug is that in the case of an interface of type vif which is later
> renamed (by the code around line 75 of vif-common.sh in xen-unstable),
> the shell variable dev is not changed.
> 
> The change you are proposing would also an effect in the case of
> interfaces of type tap and I'm not convinced that in this case it
> would do the right thing.
> 
> Anthony, Stefano: as the authors of 21922 would you care to comment ?

I don't think that patch is the right way to fix the issue.

Does this patch fix the problem for you?


diff -r 9e463cb15658 tools/hotplug/Linux/vif-common.sh
--- a/tools/hotplug/Linux/vif-common.sh	Mon Feb 07 17:02:46 2011 +0000
+++ b/tools/hotplug/Linux/vif-common.sh	Mon Feb 07 17:19:32 2011 +0000
@@ -69,16 +69,16 @@ if [ "$type_if" = vif ]; then
 if [ "$type_if" = vif ]; then
     # Check presence of compulsory args.
     XENBUS_PATH="${XENBUS_PATH:?}"
-    vif="${vif:?}"
+    dev="${dev:?}"
 
     vifname=$(xenstore_read_default "$XENBUS_PATH/vifname" "")
     if [ "$vifname" ]
     then
         if [ "$command" == "online" ] && ! ip link show "$vifname" >&/dev/null
         then
-            do_or_die ip link set "$vif" name "$vifname"
+            do_or_die ip link set "$dev" name "$vifname"
         fi
-        vif="$vifname"
+        dev="$vifname"
     fi
 elif [ "$type_if" = tap ]; then
     # Check presence of compulsory args.
@@ -105,9 +105,9 @@ frob_iptable()
     local c="-D"
   fi
 
-  iptables "$c" FORWARD -m physdev --physdev-is-bridged --physdev-in "$vif" \
+  iptables "$c" FORWARD -m physdev --physdev-is-bridged --physdev-in "$dev" \
     "$@" -j ACCEPT 2>/dev/null &&
-  iptables "$c" FORWARD -m physdev --physdev-is-bridged --physdev-out "$vif" \
+  iptables "$c" FORWARD -m physdev --physdev-is-bridged --physdev-out "$dev" \
     -j ACCEPT 2>/dev/null
 
   if [ "$command" == "online" -a $? -ne 0 ]