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

[Numan Siddique]

On Tue, Mar 10, 2020 at 10:10 PM Dumitru Ceara <dceara at redhat.com> wrote:
>
> 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":
> https://bugzilla.redhat.com/show_bug.cgi?id=1808125#c6
>
> 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>

Acked-by: Numan Siddique <numans at ovn.org>

Thanks
Numan

>
> ---
> v2:
> - 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)) {
>              continue;
>          }
> --
> 1.8.3.1
>
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