From patchwork Thu Mar 7 03:08:32 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Si-Wei Liu X-Patchwork-Id: 1052633 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming-netdev@ozlabs.org Delivered-To: patchwork-incoming-netdev@ozlabs.org Authentication-Results: ozlabs.org; spf=none (mailfrom) smtp.mailfrom=vger.kernel.org (client-ip=209.132.180.67; helo=vger.kernel.org; envelope-from=netdev-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=pass (p=none dis=none) header.from=oracle.com Authentication-Results: ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=oracle.com header.i=@oracle.com header.b="tlM/1oCJ"; dkim-atps=neutral Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 44FGTZ3PRzz9s7T for ; Thu, 7 Mar 2019 14:34:42 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726186AbfCGDdv (ORCPT ); Wed, 6 Mar 2019 22:33:51 -0500 Received: from aserp2130.oracle.com ([141.146.126.79]:54834 "EHLO aserp2130.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725793AbfCGDdv (ORCPT ); Wed, 6 Mar 2019 22:33:51 -0500 Received: from pps.filterd (aserp2130.oracle.com [127.0.0.1]) by aserp2130.oracle.com (8.16.0.27/8.16.0.27) with SMTP id x273P07G060587; Thu, 7 Mar 2019 03:33:41 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=from : to : cc : subject : date : message-id; s=corp-2018-07-02; bh=jrCGb2a7ZjGNsCrGDHG2ZKRzbO1lKLSdnH9w/iC1ryY=; b=tlM/1oCJNY2j8T6hhsh4rJyMXXj+SbvZpXqBmdaPwpFr5z0E66M3sZnBpNgIN0XWPGLE ISdUcgSaF0EGYn6fQ/FsrG3fe0sll1Db0O4ukFZvV6pKqxJuI0hvBSNbqhOrbS4ZOJ6X RWnPnZpItI3On59fGZMNL0wrp1xlIAHxgpI7AH2/1x4tYu7kh8p5KRb4d0lxhdAR25c4 Lp4B1U1pLGEctnRXMbm2Bs8rec1085QyKjWcQEjPHIYX+CQf6GDSaXykITZ4OUaQMpEY GG5I6Gd1uNyO2xA4J+Rol07og3hHmwKqZE1Im7YEDtI8Ki9WN2JcAE5tZ9rL+YPslLPR LQ== Received: from userv0022.oracle.com (userv0022.oracle.com [156.151.31.74]) by aserp2130.oracle.com with ESMTP id 2qyfbefsr2-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 07 Mar 2019 03:33:40 +0000 Received: from userv0122.oracle.com (userv0122.oracle.com [156.151.31.75]) by userv0022.oracle.com (8.14.4/8.14.4) with ESMTP id x273XY2M002020 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 7 Mar 2019 03:33:35 GMT Received: from abhmp0004.oracle.com (abhmp0004.oracle.com [141.146.116.10]) by userv0122.oracle.com (8.14.4/8.14.4) with ESMTP id x273XXdg030056; Thu, 7 Mar 2019 03:33:33 GMT Received: from ban25x6uut24.us.oracle.com (/10.153.73.24) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Wed, 06 Mar 2019 19:33:32 -0800 From: Si-Wei Liu To: "Michael S. Tsirkin" , Sridhar Samudrala , Alexander Duyck , Stephen Hemminger , Jakub Kicinski , Jiri Pirko , David Miller , Netdev , virtualization@lists.linux-foundation.org Cc: liran.alon@oracle.com, boris.ostrovsky@oracle.com, vijay.balakrishna@oracle.com, si-wei liu Subject: [PATCH net v2] failover: allow name change on IFF_UP slave interfaces Date: Wed, 6 Mar 2019 22:08:32 -0500 Message-Id: <1551928112-32109-1-git-send-email-si-wei.liu@oracle.com> X-Mailer: git-send-email 1.8.3.1 X-Proofpoint-Virus-Version: vendor=nai engine=5900 definitions=9187 signatures=668685 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1011 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1903070022 Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org When a netdev appears through hot plug then gets enslaved by a failover master that is already up and running, the slave will be opened right away after getting enslaved. Today there's a race that userspace (udev) may fail to rename the slave if the kernel (net_failover) opens the slave earlier than when the userspace rename happens. Unlike bond or team, the primary slave of failover can't be renamed by userspace ahead of time, since the kernel initiated auto-enslavement is unable to, or rather, is never meant to be synchronized with the rename request from userspace. As the failover slave interfaces are not designed to be operated directly by userspace apps: IP configuration, filter rules with regard to network traffic passing and etc., should all be done on master interface. In general, userspace apps only care about the name of master interface, while slave names are less important as long as admin users can see reliable names that may carry other information describing the netdev. For e.g., they can infer that "ens3nsby" is a standby slave of "ens3", while for a name like "eth0" they can't tell which master it belongs to. Historically the name of IFF_UP interface can't be changed because there might be admin script or management software that is already relying on such behavior and assumes that the slave name can't be changed once UP. But failover is special: with the in-kernel auto-enslavement mechanism, the userspace expectation for device enumeration and bring-up order is already broken. Previously initramfs and various userspace config tools were modified to bypass failover slaves because of auto-enslavement and duplicate MAC address. Similarly, in case that users care about seeing reliable slave name, the new type of failover slaves needs to be taken care of specifically in userspace anyway. It's less risky to lift up the rename restriction on failover slave which is already UP. Although it's possible this change may potentially break userspace component (most likely configuration scripts or management software) that assumes slave name can't be changed while UP, it's relatively a limited and controllable set among all userspace components, which can be fixed specifically to work with the new naming behavior of failover slaves. Userspace component interacting with slaves should be changed to operate on failover master instead, as the failover slave is dynamic in nature which may come and go at any point. The goal is to make the role of failover slaves less relevant, and all userspace should only deal with master in the long run. Fixes: 30c8bd5aa8b2 ("net: Introduce generic failover module") Signed-off-by: Si-Wei Liu Reviewed-by: Liran Alon Acked-by: Michael S. Tsirkin --- v1 -> v2: - Drop configurable module parameter (Sridhar) include/linux/netdevice.h | 3 +++ net/core/dev.c | 3 ++- net/core/failover.c | 6 +++--- 3 files changed, 8 insertions(+), 4 deletions(-) diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h index 857f8ab..6d9e4e0 100644 --- a/include/linux/netdevice.h +++ b/include/linux/netdevice.h @@ -1487,6 +1487,7 @@ struct net_device_ops { * @IFF_NO_RX_HANDLER: device doesn't support the rx_handler hook * @IFF_FAILOVER: device is a failover master device * @IFF_FAILOVER_SLAVE: device is lower dev of a failover master device + * @IFF_SLAVE_RENAME_OK: rename is allowed while slave device is running */ enum netdev_priv_flags { IFF_802_1Q_VLAN = 1<<0, @@ -1518,6 +1519,7 @@ enum netdev_priv_flags { IFF_NO_RX_HANDLER = 1<<26, IFF_FAILOVER = 1<<27, IFF_FAILOVER_SLAVE = 1<<28, + IFF_SLAVE_RENAME_OK = 1<<29, }; #define IFF_802_1Q_VLAN IFF_802_1Q_VLAN @@ -1548,6 +1550,7 @@ enum netdev_priv_flags { #define IFF_NO_RX_HANDLER IFF_NO_RX_HANDLER #define IFF_FAILOVER IFF_FAILOVER #define IFF_FAILOVER_SLAVE IFF_FAILOVER_SLAVE +#define IFF_SLAVE_RENAME_OK IFF_SLAVE_RENAME_OK /** * struct net_device - The DEVICE structure. diff --git a/net/core/dev.c b/net/core/dev.c index 722d50d..ae070de 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -1180,7 +1180,8 @@ int dev_change_name(struct net_device *dev, const char *newname) BUG_ON(!dev_net(dev)); net = dev_net(dev); - if (dev->flags & IFF_UP) + if (dev->flags & IFF_UP && + !(dev->priv_flags & IFF_SLAVE_RENAME_OK)) return -EBUSY; write_seqcount_begin(&devnet_rename_seq); diff --git a/net/core/failover.c b/net/core/failover.c index 4a92a98..34c5c87 100644 --- a/net/core/failover.c +++ b/net/core/failover.c @@ -80,14 +80,14 @@ static int failover_slave_register(struct net_device *slave_dev) goto err_upper_link; } - slave_dev->priv_flags |= IFF_FAILOVER_SLAVE; + slave_dev->priv_flags |= (IFF_FAILOVER_SLAVE | IFF_SLAVE_RENAME_OK); if (fops && fops->slave_register && !fops->slave_register(slave_dev, failover_dev)) return NOTIFY_OK; netdev_upper_dev_unlink(slave_dev, failover_dev); - slave_dev->priv_flags &= ~IFF_FAILOVER_SLAVE; + slave_dev->priv_flags &= ~(IFF_FAILOVER_SLAVE | IFF_SLAVE_RENAME_OK); err_upper_link: netdev_rx_handler_unregister(slave_dev); done: @@ -121,7 +121,7 @@ int failover_slave_unregister(struct net_device *slave_dev) netdev_rx_handler_unregister(slave_dev); netdev_upper_dev_unlink(slave_dev, failover_dev); - slave_dev->priv_flags &= ~IFF_FAILOVER_SLAVE; + slave_dev->priv_flags &= ~(IFF_FAILOVER_SLAVE | IFF_SLAVE_RENAME_OK); if (fops && fops->slave_unregister && !fops->slave_unregister(slave_dev, failover_dev))