lvmlockd: reconnect to lvmetad if it's restarted

If lvmetad is restarted after lvmlockd has connected
to it, then lvmlockd should reconnect.

daemons/lvmlockd/lvmlockd-core.c

@@ -1020,6 +1020,43 @@ static void add_work_action(struct action *act)
 	pthread_mutex_unlock(&worker_mutex);
 }
 
+static daemon_reply send_lvmetad(const char *id, ...)
+{
+	daemon_reply reply;
+	va_list ap;
+	int retries = 0;
+
+	va_start(ap, id);
+
+	/*
+	 * mutex is used because all threads share a single
+	 * lvmetad connection/handle.
+	 */
+	pthread_mutex_lock(&lvmetad_mutex);
+retry:
+	reply = daemon_send_simple_v(lvmetad_handle, id, ap);
+
+	/* lvmetad may have been restarted */
+	if ((reply.error == ECONNRESET) && (retries < 2)) {
+		daemon_close(lvmetad_handle);
+		lvmetad_connected = 0;
+
+		lvmetad_handle = lvmetad_open(NULL);
+		if (lvmetad_handle.error || lvmetad_handle.socket_fd < 0) {
+			log_error("lvmetad_open reconnect error %d", lvmetad_handle.error);
+		} else {
+			log_debug("lvmetad reconnected");
+			lvmetad_connected = 1;
+		}
+		retries++;
+		goto retry;
+	}
+	pthread_mutex_unlock(&lvmetad_mutex);
+
+	va_end(ap);
+	return reply;
+}
+
 static int res_lock(struct lockspace *ls, struct resource *r, struct action *act, int *retry)
 {
 	struct lock *lk;
@@ -1246,14 +1283,12 @@ static int res_lock(struct lockspace *ls, struct resource *r, struct action *act
 		else
 			uuid = ls->vg_uuid;
 
-		pthread_mutex_lock(&lvmetad_mutex);
+		reply = send_lvmetad("set_vg_info",
-		reply = daemon_send_simple(lvmetad_handle, "set_vg_info",
 				     "token = %s", "skip",
 				     "uuid = %s", uuid,
 				     "name = %s", ls->vg_name,
 				     "version = " FMTd64, (int64_t)new_version,
 				     NULL);
-			pthread_mutex_unlock(&lvmetad_mutex);
 
 		if (reply.error || strcmp(daemon_reply_str(reply, "response", ""), "OK"))
 			log_error("set_vg_info in lvmetad failed %d", reply.error);
@@ -1266,12 +1301,10 @@ static int res_lock(struct lockspace *ls, struct resource *r, struct action *act
 		log_debug("S %s R %s res_lock set lvmetad global invalid",
 			  ls->name, r->name);
 
-		pthread_mutex_lock(&lvmetad_mutex);
+		reply = send_lvmetad("set_global_info",
-		reply = daemon_send_simple(lvmetad_handle, "set_global_info",
 				     "token = %s", "skip",
 				     "global_invalid = " FMTd64, INT64_C(1),
 				     NULL);
-		pthread_mutex_unlock(&lvmetad_mutex);
 
 		if (reply.error || strcmp(daemon_reply_str(reply, "response", ""), "OK"))
 			log_error("set_global_info in lvmetad failed %d", reply.error);
@@ -4747,15 +4780,11 @@ static int get_lockd_vgs(struct list_head *vg_lockd)
 	const char *lock_type;
 	const char *lock_args;
 	char find_str_path[PATH_MAX];
-	int mutex_unlocked = 0;
 	int rv = 0;
 
 	INIT_LIST_HEAD(&update_vgs);
 
-	pthread_mutex_lock(&lvmetad_mutex);
+	reply = send_lvmetad("vg_list", "token = %s", "skip", NULL);
-	reply = daemon_send_simple(lvmetad_handle, "vg_list",
-				   "token = %s", "skip",
-				   NULL);
 
 	if (reply.error || strcmp(daemon_reply_str(reply, "response", ""), "OK")) {
 		log_error("vg_list from lvmetad failed %d", reply.error);
@@ -4792,7 +4821,7 @@ static int get_lockd_vgs(struct list_head *vg_lockd)
 	/* get vg_name and lock_type for each vg uuid entry in update_vgs */
 
 	list_for_each_entry(ls, &update_vgs, list) {
-		reply = daemon_send_simple(lvmetad_handle, "vg_lookup",
+		reply = send_lvmetad("vg_lookup",
 				     "token = %s", "skip",
 				     "uuid = %s", ls->vg_uuid,
 				     NULL);
@@ -4884,8 +4913,6 @@ static int get_lockd_vgs(struct list_head *vg_lockd)
 		if (rv < 0)
 			break;
 	}
-	pthread_mutex_unlock(&lvmetad_mutex);
-	mutex_unlocked = 1;
 out:
 	/* Return lockd VG's on the vg_lockd list. */
 
@@ -4898,9 +4925,6 @@ out:
 			free(ls);
 	}
 
-	if (!mutex_unlocked)
-		pthread_mutex_unlock(&lvmetad_mutex);
-
 	return rv;
 }