[PATCH 1/1] bridge_driver: use ovs-vsctl to setup and clean Qos when

[Laine Stump]

On 11/8/21 5:18 AM, Michal Prívozník wrote:
> On 11/3/21 4:11 AM, jx8zjs wrote:
>> From: zhangjl02 <zhangjl02 at inspur.com>
>>
>> Fix bug 1826168: bridge type network with ovs bridge can start with Qos
>> setting which do not take any effect
>>
>> Resolves:https://bugzilla.redhat.com/show_bug.cgi?id=1826168
>> Signed-off-by: zhangjl02 <zhangjl02 at inspur.com>
>> ---
>>   src/network/bridge_driver.c | 65 +++++++++++++++++++++++++++++++------
>>   1 file changed, 55 insertions(+), 10 deletions(-)
>>
>> diff --git a/src/network/bridge_driver.c b/src/network/bridge_driver.c
>> index 498c45d0a7..d0627848cd 100644
>> --- a/src/network/bridge_driver.c
>> +++ b/src/network/bridge_driver.c
>> @@ -2305,6 +2305,15 @@ networkAddRouteToBridge(virNetworkObj *obj,
>>   }
>>   
>>   
>> +static int
>> +networkDefIsOvsBridge(virNetworkDef *def)
> 
> This @def should have been const too. And function returns a bool,
> effectively.
> 
>> +{
>> +    const virNetDevVPortProfile *vport = def->virtPortProfile;
>> +    return vport &&
>> +        vport->virtPortType == VIR_NETDEV_VPORT_PROFILE_OPENVSWITCH;
>> +}
>> +
>> +
>>   static int
>>   networkStartNetworkVirtual(virNetworkDriverState *driver,
>>                              virNetworkObj *obj)
>> @@ -2320,6 +2329,7 @@ networkStartNetworkVirtual(virNetworkDriverState *driver,
>>       bool dnsmasqStarted = false;
>>       bool devOnline = false;
>>       bool firewalRulesAdded = false;
>> +    bool ovsType = networkDefIsOvsBridge(def);
>>   
>>       /* Check to see if any network IP collides with an existing route */
>>       if (networkCheckRouteCollision(def) < 0)
>> @@ -2439,15 +2449,29 @@ networkStartNetworkVirtual(virNetworkDriverState *driver,
>>       if (v6present && networkStartRadvd(driver, obj) < 0)
>>           goto error;
>>   
>> -    if (virNetDevBandwidthSet(def->bridge, def->bandwidth, true, true) < 0)
>> -        goto error;
>> +    if (ovsType) {
>> +        if (virNetDevOpenvswitchInterfaceSetQos(def->bridge, def->bandwidth,
>> +                                                def->uuid,
>> +                                                true) < 0)
>> +            goto error;
>> +    } else {
>> +        if (virNetDevBandwidthSet(def->bridge, def->bandwidth, true, true) < 0)
>> +            goto error;
>> +    }
> 
> I don't think this should be here. At this point, the bridge was created
> using netlink (definitely NOT ovs-vsctl add-br). Therefore,
> virNetDevOpenvswitchInterfaceSetQos() must fail because it won't be able
> to find any ports/queues/...

Beyond that, networks of the type that would end up calling 
networkStartNetworkVirtual (forward modes 'route' and "nat') don't 
support using OVS bridges anyway, so this code in 
networkStartNetworkVirtual and networkShutdownNetworkVirtual will never 
be executed anyway.

> 
>>   
>>       return 0;
>>   
>>    error:
>>       virErrorPreserveLast(&save_err);
>> -    if (def->bandwidth)
>> -       virNetDevBandwidthClear(def->bridge);
>> +    if (ovsType) {
>> +        if (virNetDevOpenvswitchInterfaceClearQos(def->bridge, def->uuid) < 0)
>> +            VIR_WARN("cannot clear bandwidth setting for ovs bridge : %s",
>> +                     def->bridge);
>> +    } else {
>> +        if (def->bandwidth) {
>> +            virNetDevBandwidthClear(def->bridge);
>> +        }
>> +    }
>>   
> 
> Similarly, this shouldn't be here either.
> 
>>       if (dnsmasqStarted) {
>>           pid_t dnsmasqPid = virNetworkObjGetDnsmasqPid(obj);
>> @@ -2536,13 +2560,21 @@ static int
>>   networkStartNetworkBridge(virNetworkObj *obj)
>>   {
>>       virNetworkDef *def = virNetworkObjGetDef(obj);
>> +    bool ovsType = networkDefIsOvsBridge(def);
>>   
>>       /* put anything here that needs to be done each time a network of
>>        * type BRIDGE, is started. On failure, undo anything you've done,
>>        * and return -1. On success return 0.
>>        */
>> -    if (virNetDevBandwidthSet(def->bridge, def->bandwidth, true, true) < 0)
>> -        goto error;
>> +    if (ovsType) {
>> +        if (virNetDevOpenvswitchInterfaceSetQos(def->bridge, def->bandwidth,
>> +                                                def->uuid,
>> +                                                true) < 0)
>> +            goto error;
>> +    } else {
>> +        if (virNetDevBandwidthSet(def->bridge, def->bandwidth, true, true) < 0)
>> +            goto error;
>> +    }
>>   
>>       if (networkStartHandleMACTableManagerMode(obj) < 0)
>>           goto error;
>> @@ -2550,8 +2582,15 @@ networkStartNetworkBridge(virNetworkObj *obj)
>>       return 0;
>>   
>>    error:
>> -    if (def->bandwidth)
>> -       virNetDevBandwidthClear(def->bridge);
>> +    if (ovsType) {
>> +        if (virNetDevOpenvswitchInterfaceClearQos(def->bridge, def->uuid) < 0)
>> +            VIR_WARN("cannot clear bandwidth setting for ovs bridge : %s",
>> +                     def->bridge);
>> +    } else {
>> +        if (def->bandwidth) {
>> +            virNetDevBandwidthClear(def->bridge);
>> +        }
>> +    }
>>       return -1;
>>   }
>>   
>> @@ -2565,9 +2604,15 @@ networkShutdownNetworkBridge(virNetworkObj *obj G_GNUC_UNUSED)
>>        * type BRIDGE is shutdown. On failure, undo anything you've done,
>>        * and return -1. On success return 0.
>>        */
>> -    if (def->bandwidth)
>> -       virNetDevBandwidthClear(def->bridge);
>>   
>> +    if (networkDefIsOvsBridge(def)) {
>> +        if (virNetDevOpenvswitchInterfaceClearQos(def->bridge, def->uuid) < 0)
>> +            VIR_WARN("cannot clear bandwidth setting for ovs bridge : %s",
>> +                     def->bridge);
>> +    } else {
>> +        if (def->bandwidth)
>> +            virNetDevBandwidthClear(def->bridge);
>> +    }
>>       return 0;
>>   }
>>   
>>
> 
> Alright, these last three hunks are important because they set QoS on
> the correct type of network. But I wonder if they belong in libvirt at
> all. I mean, the sole purpose of having openvswitch type of network is
> that libvirt just plugs TAPs into an OVS controlled bridge without
> touching it in any other way. IOW, the OVS bridge is created and
> controlled outside of libvirt. That may include configuring QoS. Merging
> this patch would open a pandora's box: what should happen if
> <bandwidth/> is configured in network XML and there's some QoS already
> set on the bridge?

That was my thought too. Although I looked back in the git history and 
saw that support for setting the bandwidth of forward mode='bridge' (aka 
"unamanaged bridge network") was added incidentally as a part of 
decoupling the network driver from the hypervisor drivers:

https://gitlab.com/libvirt/libvirt/-/commit/0a85aad582322034b758f8aa0199641b42be173e

which was a bugfix on top of

https://gitlab.com/libvirt/libvirt/-/commit/42a92ee93d5432ebd9ebfd409903b5287fc7d7ff

So setting the QoS for an unmanaged bridge goes against the original 
philosophy of that type of network, but we already do it in the case of 
Linux host bridges. I suppose if someone goes to the effort of adding 
the extra config to set bandwidth, then they must know that this is 
going to trash any existing bandwidth setting for the bridge, and are 
willing to accept that (most likely because they *haven't* set anything 
directly via OVS).