commit ef9b56022c656df34044103a317b7b890ced6628
Author: Willy Tarreau <w@1wt.eu>
Date:   Tue Aug 7 10:14:53 2018 +0200

    BUG/MEDIUM: servers: check the queues once enabling a server
    
    Commit 64cc49c ("MAJOR: servers: propagate server status changes
    asynchronously.") heavily changed the way the server states are
    updated since they became asynchronous. During this change, some
    code was lost, which is used to shut down some sessions from a
    backup server and to pick pending connections from a proxy once
    a server is turned back from maintenance to ready state. The
    effect is that when temporarily disabling a server, connections
    stay in the backend's queue, and when re-enabling it, they are
    not picked and they expire in the backend's queue. Now they're
    properly picked again.
    
    This fix must be backported to 1.8.
    
    (cherry picked from commit 6a78e61694d69beb49c0e8486be9550f5e8b7d08)
    Signed-off-by: Willy Tarreau <w@1wt.eu>

diff --git a/src/server.c b/src/server.c
index 3d6a4093..fbed6cd4 100644
--- a/src/server.c
+++ b/src/server.c
@@ -4774,6 +4774,19 @@ void srv_update_status(struct server *s)
 		if (prev_srv_count && s->proxy->srv_bck == 0 && s->proxy->srv_act == 0)
 			set_backend_down(s->proxy);
 
+		/* If the server is set with "on-marked-up shutdown-backup-sessions",
+		 * and it's not a backup server and its effective weight is > 0,
+		 * then it can accept new connections, so we shut down all streams
+		 * on all backup servers.
+		 */
+		if ((s->onmarkedup & HANA_ONMARKEDUP_SHUTDOWNBACKUPSESSIONS) &&
+		    !(s->flags & SRV_F_BACKUP) && s->next_eweight)
+			srv_shutdown_backup_streams(s->proxy, SF_ERR_UP);
+
+		/* check if we can handle some connections queued at the proxy. We
+		 * will take as many as we can handle.
+		 */
+		xferred = pendconn_grab_from_px(s);
 	}
 	else if (s->next_admin & SRV_ADMF_MAINT) {
 		/* remaining in maintenance mode, let's inform precisely about the