network: Makes vlan network interfaces set mtu before upscript called

This is consistent with veth and ipvlan types.

Also makes the debug message for success occur after up script has run.

Also makes device clean up on error more thorough and consistent.

Signed-off-by: tomponline <thomas.parrott@canonical.com>

src/lxc/network.c

@@ -555,8 +555,23 @@ static int instantiate_vlan(struct lxc_handler *handler, struct lxc_netdev *netd
 	netdev->ifindex = if_nametoindex(peer);
 	if (!netdev->ifindex) {
 		ERROR("Failed to retrieve ifindex for \"%s\"", peer);
-		lxc_netdev_delete_by_name(peer);
-		return -1;
+		goto on_error;
+	}
+
+	if (netdev->mtu) {
+		err = lxc_safe_uint(netdev->mtu, &mtu);
+		if (err < 0) {
+			errno = -err;
+			SYSERROR("Failed to parse mtu \"%s\" for interface \"%s\"", netdev->mtu, peer);
+			goto on_error;
+		}
+
+		err = lxc_netdev_set_mtu(peer, mtu);
+		if (err) {
+			errno = -err;
+			SYSERROR("Failed to set mtu \"%s\" for interface \"%s\"", netdev->mtu, peer);
+			goto on_error;
+		}
 	}
 
 	if (netdev->upscript) {
@@ -570,32 +585,18 @@ static int instantiate_vlan(struct lxc_handler *handler, struct lxc_netdev *netd
 				handler->conf->hooks_version, "net",
 				netdev->upscript, "up", argv);
 		if (err < 0) {
-			lxc_netdev_delete_by_name(peer);
-			return -1;
+			goto on_error;
 		}
 	}
 
 	DEBUG("Instantiated vlan \"%s\" with ifindex is \"%d\" (vlan1000)",
 	      peer, netdev->ifindex);
-	if (netdev->mtu) {
-		if (lxc_safe_uint(netdev->mtu, &mtu) < 0) {
-			ERROR("Failed to retrieve mtu from \"%d\"/\"%s\".",
-			      netdev->ifindex,
-			      netdev->name[0] != '\0' ? netdev->name : "(null)");
-			return -1;
-		}
-
-		err = lxc_netdev_set_mtu(peer, mtu);
-		if (err) {
-			errno = -err;
-			SYSERROR("Failed to set mtu \"%s\" for \"%s\"",
-			         netdev->mtu, peer);
-			lxc_netdev_delete_by_name(peer);
-			return -1;
-		}
-	}
 
 	return 0;
+
+on_error:
+	lxc_netdev_delete_by_name(peer);
+	return -1;
 }
 
 static int instantiate_phys(struct lxc_handler *handler, struct lxc_netdev *netdev)