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author | Ian Campbell <ian.campbell@citrix.com> | 2012-07-23 13:09:46 +0100 |
---|---|---|
committer | Ian Campbell <ian.campbell@citrix.com> | 2012-07-23 13:09:46 +0100 |
commit | 931116a29046a91fa072d0cae4523ee9e8529c4f (patch) | |
tree | 6c79b5ecbb1d658955cbfcb6e50f2655ce8038ae /tools/hotplug | |
parent | ed78b8ba6619d054020b2738eabe323ca4a25d68 (diff) | |
download | xen-931116a29046a91fa072d0cae4523ee9e8529c4f.tar.gz xen-931116a29046a91fa072d0cae4523ee9e8529c4f.tar.bz2 xen-931116a29046a91fa072d0cae4523ee9e8529c4f.zip |
hotplug: vif: fail if a duplicate vifname is used.
This is based on a patch from Hans van Kranenburg in
http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=658305. Quoting that bug
report:
When configurating a duplicate custom vifname for interfaces in the Xen
dom0 that are added to a bridge (which is obviously a configuration error),
the hotplug scripts fail silently to rename the new vifX.0 to
the custom vifname, if it's already existing.
The result of this, is that the domU will start normally, but no network
traffic between domU and the dom0 bridge is possible, because the vifX.0
never gets added to the bridge.
Worse... when doing xm shutdown on the newly created domU, while
investigating the issue, the interface of another running domU gets shut
down, and remains hanging around in a DOWN state, because it cannot be
removed (the other unrelated domU is still running, but succesfully made
unavailable on the network!).
When starting the new domU again, the interface of the other domU will
be added to the bridge again, and while looking at the output of brctl
show, tcpdump and ping, which make no sense, because everything will
seem to be right, nagios will notify you of another host being down. :|
Note that libxl doesn't actually check the hotplug status yet, this changes
with Rogers hotplug script changes. xend correctly picks the failure up.
Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>
Committed-by: Ian Campbell <ian.campbell@citrix.com>
Diffstat (limited to 'tools/hotplug')
-rw-r--r-- | tools/hotplug/Linux/vif-common.sh | 22 |
1 files changed, 18 insertions, 4 deletions
diff --git a/tools/hotplug/Linux/vif-common.sh b/tools/hotplug/Linux/vif-common.sh index fff22bbf9d..a8bd19a6a3 100644 --- a/tools/hotplug/Linux/vif-common.sh +++ b/tools/hotplug/Linux/vif-common.sh @@ -65,6 +65,20 @@ case "$command" in ;; esac +rename_vif() { + local dev=$1 + local vifname=$2 + + # if a custom vifname was chosen and a link with that desired name + # already exists, then stop, before messing up whatever is using + # that interface (e.g. another running domU) because it's likely a + # configuration error + if ip link show "$vifname" >&/dev/null + then + fatal "Cannot rename interface $dev. An interface with name $vifname already exists." + fi + do_or_die ip link set "$dev" name "$vifname" +} if [ "$type_if" = vif ]; then # Check presence of compulsory args. @@ -74,9 +88,9 @@ if [ "$type_if" = vif ]; then vifname=$(xenstore_read_default "$XENBUS_PATH/vifname" "") if [ "$vifname" ] then - if [ "$command" == "online" ] && ! ip link show "$vifname" >&/dev/null + if [ "$command" == "online" ] then - do_or_die ip link set "$dev" name "$vifname" + rename_vif "$dev" "$vifname" fi dev="$vifname" fi @@ -96,9 +110,9 @@ elif [ "$type_if" = tap ]; then if [ "$vifname" ] then vifname="${vifname}-emu" - if [ "$command" == "add" ] && ! ip link show "$vifname" >&/dev/null + if [ "$command" == "add" ] then - do_or_die ip link set "$dev" name "$vifname" + rename_vif "$dev" "$vifname" fi dev="$vifname" fi |