[ovs-dev] [PATCH v2] ovsdb-idl.c: Clear conditions when clearing IDL.

Dumitru Ceara dceara at redhat.com
Tue Mar 10 16:39:35 UTC 2020

If the ovsdb-server reply to "monitor_cond_since" requests has
"found" == false then ovsdb_idl_db_parse_monitor_reply() calls
ovsdb_idl_db_clear() which iterates through all tables and
unconditionally sets table->cond_changed to false.

However, if the client had already set a new condition for some of the
tables, this new condition request will never be sent to ovsdb-server
until the condition is reset to a different value. This is due to the
check in ovsdb_idl_db_set_condition().

In order to fix this we now also call ovsdb_idl_condition_clear() for
each table condition in ovsdb_idl_db_clear(). This ensures that
resetting the condition to the same value as before the
"monitor_cond_since" reply will trigger a new request.

One way to replicate the issue is described in the bugzilla reporting
the bug, when ovn-controller is configured to use "ovn-monitor-all":

Reported-by: Dan Williams <dcbw at redhat.com>
Reported-at: https://bugzilla.redhat.com/1808125
CC: Andy Zhou <azhou at ovn.org>
Fixes: 5351980b047f ("ovsdb-idl: Avoid sending redundant conditional monitoring updates")
Signed-off-by: Dumitru Ceara <dceara at redhat.com>

- Updated commit log so that the "Fixes:" tag reflects the correct
  commit that introduced the issue.
 lib/ovsdb-idl.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/lib/ovsdb-idl.c b/lib/ovsdb-idl.c
index 190143f..64721ca 100644
--- a/lib/ovsdb-idl.c
+++ b/lib/ovsdb-idl.c
@@ -610,7 +610,11 @@ ovsdb_idl_db_clear(struct ovsdb_idl_db *db)
         struct ovsdb_idl_table *table = &db->tables[i];
         struct ovsdb_idl_row *row, *next_row;
-        table->cond_changed = false;
+        if (table->cond_changed) {
+            table->cond_changed = false;
+            ovsdb_idl_condition_clear(&table->condition);
+        }
         if (hmap_is_empty(&table->rows)) {

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