Hi, Ben
I see some netdev which is not added to ovs constructs and destructs
frequently because of route_table_handle_msg(). and there may be some side
effects everytime reopen the netdev, such as netdev_change_seq_changed.

Is it neccessy that open a netdev not in ovs?
How about not open netdev or return failure for it?

Thanks
Huanle


On Fri, Jul 14, 2017 at 2:33 AM, Ben Pfaff <[email protected]> wrote:

> On Wed, Jul 05, 2017 at 05:03:06PM +0200, Eelco Chaudron wrote:
> > On 23/06/17 10:37, Eelco Chaudron wrote:
> > >On 06/23/2017 02:12 AM, Ben Pfaff wrote:
> > >>On Thu, Jun 22, 2017 at 04:04:44PM -0300, Flavio Leitner wrote:
> > >>>On Thu, Jun 22, 2017 at 01:04:59AM +0800, Huanle Han wrote:
> > >>>>Hi,all
> > >>>>
> > >>>>I get this problem with latest(dbd8112) branch-2.7 code on my Ubuntu.
> > >>>>root@ubuntu:/var/log/# ovs-vsctl show
> > >>>>adf2ea99-0c53-4180-914f-7dadaa71302b
> > >>>>     Bridge test
> > >>>>         Port test
> > >>>>             Interface test
> > >>>>                 type: internal
> > >>>>     Bridge "manage"
> > >>>>         Port "manage"
> > >>>>             Interface "manage"
> > >>>>                 type: internal
> > >>>>                 error: "could not open network device manage (File
> > >>>>exists)"
> > >>>>         Port "veth0"
> > >>>>             Interface "veth0"
> > >>>>         Port "eth0"
> > >>>>             Interface "eth0"
> > >>>>     ovs_version: "2.7.0"
> > >>>>
> > >>>>How to reproduce:
> > >>>>1. add bridge "manage", up and add ip on it
> > >>>>2. restart ovs-vswitchd
> > >>>>3. "ovs-vsctl show" displays error message.
> > >>>>
> > >>>>The reason:
> > >>>>In following "netdev_open" call on ovs-vswitchd start, input "type"
> > >>>>is NULL
> > >>>>and "manage" is opened as a "system" netdev_class iface incorrectly.
> > >>>>
> > >>>>#0  netdev_open (name=0x7fffffffe2bc "manage", type=0x0,
> > >>>>netdevp=0x7fffffffc3b0) at ../lib/netdev.c:396
> > >>>>#1  0x000000000052c492 in get_src_addr (ip6_dst=0x7fffffffe2ac,
> > >>>>output_bridge=0x7fffffffe2bc "manage", psrc=0x8f3490) at
> > >>>>../lib/ovs-router.c:141
> > >>>>#2  0x000000000052c85d in ovs_router_insert__ (priority=104 'h',
> > >>>>ip6_dst=0x7fffffffe29c, plen=104 'h', output_bridge=0x7fffffffe2bc
> > >>>>"manage", gw=0x7fffffffe2ac) at ../lib/ovs-router.c:202
> > >>>>#3  0x000000000052c980 in ovs_router_insert (ip_dst=0x7fffffffe29c,
> > >>>>plen=104 'h', output_bridge=0x7fffffffe2bc "manage",
> > >>>>gw=0x7fffffffe2ac) at
> > >>>>../lib/ovs-router.c:228
> > >>>>#4  0x000000000058f63a in route_table_handle_msg
> > >>>>(change=0x7fffffffe290) at
> > >>>>../lib/route-table.c:295
> > >>>>#5  0x000000000058f1da in route_table_reset () at
> > >>>>../lib/route-table.c:174
> > >>>>#6  0x000000000058f034 in route_table_init () at
> > >>>>../lib/route-table.c:110
> > >>>>#7  0x0000000000495838 in dp_initialize () at ../lib/dpif.c:126
> > >>>>#8  0x0000000000495b40 in dp_enumerate_types (types=0x7fffffffe3a0)
> at
> > >>>>../lib/dpif.c:244
> > >>>>#9  0x000000000042eb1c in enumerate_types (types=0x7fffffffe3a0) at
> > >>>>../ofproto/ofproto-dpif.c:267
> > >>>>#10 0x000000000041b81c in ofproto_enumerate_types
> > >>>>(types=0x7fffffffe3a0) at
> > >>>>../ofproto/ofproto.c:432
> > >>>>#11 0x000000000040df1e in bridge_run__ () at
> ../vswitchd/bridge.c:3020
> > >>>>#12 0x000000000040e196 in bridge_run () at ../vswitchd/bridge.c:3082
> > >>>>#13 0x00000000004138ef in main (argc=1, argv=0x7fffffffe578) at
> > >>>>../vswitchd/ovs-vswitchd.c:119
> > >>>>
> > >>>>After then, ovs fails to netdev_open "manage" with type ==
> "internal".
> > >>>>"File exists" error is reported.
> > >>>>I think commit d3b8f50(netdev: Fix netdev_open() to adhere to class
> > >>>>type if
> > >>>>given) introduces this problem. It need be improved.
> > >>>Your analysis is correct.  One solution is to wait vswitchd to
> > >>>configure first and only then enable ovs-route.  The problem is that
> > >>>more modules might use netdev_open() and it doesn't sound like a good
> > >>>idea to have a control per module.
> > >>>
> > >>>Another option is to map the device's info to a class instead of using
> > >>>"system", so we could use internal classes for vports, for instance.
> > >>>However, that doesn't guarantee it will match with what is configured
> > >>>in the DB.
> > >>This sounds like the kind of problem that I expected the following
> > >>commit might cause.
> > >>
> > >>     commit d3b8f5052292b3ba9084ffed097e90b87f2950f5
> > >>     Author: Eelco Chaudron <[email protected]>
> > >>     Date:   Thu Jun 1 14:38:09 2017 +0200
> > >>
> > >>         netdev: Fix netdev_open() to adhere to class type if given
> > >>
> > >>If we can't fix it somehow, we might need to revert.
> > >
> > >Reverting the above patch does not solve the real issue here. If we
> revert
> > >we
> > >donot get the error, but the wrong class is used, hence the wrong
> > >callbacks
> > >get called.
> > >
> > >The main issue is with netdev_open() being called with type = NULL
> before
> > >the interface is actually configured in the system. We could track these
> > >"auto" generated interfaces, and once netdev_open() gets called with a
> > >valid type reconfigure (re-create) it. netdev_remove() could work here
> > >but not sure if its safe due to reference counting.
> > >
> > Some background info; I see a lot of netdev_open() with a NULL type, but
> > they just grep some data and closed it again. I found that the tunnel
> code
> > is keeping a reference to the netdev (for the IP assigned) and hence it
> is
> > not going away before the "real" interface opens it.
> >
> > The change below is based on tracking the "classless" opened devices, and
> > once they get opened with a "real" class, re-create them. I did some
> basic
> > testing and it seem to work fine, also went over related code and could
> not
> > find any corner case.
> >
> > So please take a peek, and if it all makes sense I can send out an
> official
> > patch.
>
> It's not exactly pleasing, but it's the best solution I've seen so far.
>
> I wonder whether there's a way to better figure out the class type in
> advance.
>
> Let's try the solution you're proposing.  You want to send it out?
>
> Thanks,
>
> Ben.
>
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