[ovs-git] [openvswitch/ovs] bc0aa7: ovsdb-idl: Fix the database update signaling if it...
noreply at github.com
Fri Jun 11 05:07:41 UTC 2021
Author: Ilya Maximets <i.maximets at ovn.org>
Date: 2021-06-11 (Fri, 11 Jun 2021)
ovsdb-idl: Fix the database update signaling if it has never been connected.
The symptom of this issue is that OVS bridge looses its IP address on
0. start ovsdb-server and ovs-vswitchd
1. ovs-vsctl add-br br0
2. ifconfig br0 10.0.0.1 up
3. ovs-appctl -t ovs-vswitchd exit
4. start ovs-vswitchd back.
After step #3 ovs-vswitchd is down, but br0 interface exists and
has configured IP address. After step #4 there is no IP address
on the port br0.
1. ovsdb-cs connects to the database via ovsdb-idl and requests
--> get_schema for _Server database
--> lock request
2. ovsdb-cs receives schema for the _Server database. And sends
<-- schema for _Server
--> monitor_cond for _Server
3. ovsdb-cs receives lock reply.
At this point ovsdb-cs generates OVSDB_CS_EVENT_TYPE_LOCKED
event and passes it to ovsdb-idl. ovsdb-idl increases change_seqno.
4. ovsdb_idl_has_ever_connected() is 'true' now, because change_seqno
is not zero.
5. ovs-vswitchd decides that it has connection with database and
all the initial data, therefore initiates configuration of bridges.
bridge_run():ovsdb_idl_has_ever_connected() --> true
6. Since monitor request for the Open_vSwitch database is not even
sent yet, the database is empty. This leads to removal of all the
ports and all other resources.
7. When data finally received, ovs-vswitchd re-creates bridges and
ports, but IP addresses can not be restored.
While splitting out ovsdb-cs from ovsdb-idl one part of the logic
was lost. Particularly, before the split, ovsdb-idl updated
change_seqno only in MONITORING state.
Restoring the logic by updating the change_seqno only if may send
transaction, i.e. lock is ours and ovsdb-cs is in the MONITORING
state. This matches with the main purpose of increasing change_seqno
at this point, i.e. to force the client to re-try the transaction.
With this change ovsdb_idl_has_ever_connected() remains 'false'
until the first monitor reply with the actual data received.
This issue was reported several times during the last couple of weeks.
Fixes: 1c337c43ac1c ("ovsdb-idl: Break into two layers.")
Signed-off-by: Ilya Maximets <i.maximets at ovn.org>
Acked-by: Dumitru Ceara <dceara at redhat.com>
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