failover: set port status to not working if previous srv lookup failed

The meta server status consists of two parts:
A) port status - managed by failover mechanism
B) SRV lookup status - managed by SRV resolver

Both parts are resetted to "neutral" after some time, having
B timeout greater than A timeout.

We were hitting the following issue:
1. SRV lookup fails (DNS is not reachable), this will set A to
"not working and B to "resolve error". Then the next server is
tried but fails as well.

2. If SSSD tries to go back online the failover will set A to
"neutral" and it will try to resolve SRV again. But B status is
still set to "resolve error" since we haven't reached the timeout
yet and SRV resolution fails immediately. But the next server
is not tried since the port status (A) remains "neutral".

This patch sets the port status to "not working" making the
failover to continue with the next server as expected.

https://fedorahosted.org/sssd/ticket/2390

Reviewed-by: Pavel Reichl <preichl@redhat.com>
Reviewed-by: Simo Sorce <simo@redhat.com>

1 files changed, 5 insertions, 0 deletions

diff --git a/src/providers/fail_over.c b/src/providers/fail_over.c
index c45fe9c49..466e3f4de 100644
--- a/src/providers/fail_over.c
+++ b/src/providers/fail_over.c
@@ -1244,6 +1244,11 @@ resolve_srv_send(TALLOC_CTX *mem_ctx, struct tevent_context *ev,
     case SRV_RESOLVE_ERROR: /* query could not be resolved but don't retry yet */
         ret = EIO;
         state->out = server;
+
+        /* The port status was reseted to neutral but we still haven't reached
+         * timeout to try to resolve SRV record again. We will set the port
+         * status back to not working. */
+        fo_set_port_status(state->meta, PORT_NOT_WORKING);
         goto done;
     case SRV_RESOLVED:  /* The query is resolved and valid. Return. */
         state->out = server;