From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2000DC282CE for ; Fri, 5 Apr 2019 20:40:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D1ADB21855 for ; Fri, 5 Apr 2019 20:40:35 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b="IdypfwlJ" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726199AbfDEUke (ORCPT ); Fri, 5 Apr 2019 16:40:34 -0400 Received: from userp2120.oracle.com ([156.151.31.85]:58074 "EHLO userp2120.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725946AbfDEUke (ORCPT ); Fri, 5 Apr 2019 16:40:34 -0400 Received: from pps.filterd (userp2120.oracle.com [127.0.0.1]) by userp2120.oracle.com (8.16.0.27/8.16.0.27) with SMTP id x35KYFiU069528; Fri, 5 Apr 2019 20:40:19 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=subject : to : references : cc : from : message-id : date : mime-version : in-reply-to : content-type : content-transfer-encoding; s=corp-2018-07-02; bh=AbC5sIugH7Bjc397UmEDH11fQzBGjvEXcvCATIYJT8Q=; b=IdypfwlJbIdmQSf5T+hSM75t2djAXJKFhFN2J8sTVjTtdwyYQ7/crz/VIfKRf3T2TAbn VndKpdJn4C9ZQHWgwlTxMOTrZ4dSI+S4vZJHuJamIjuJFWbGsEDvivIB53XqC6A6tgT1 tErkunNFPlfZBhluVRyPvtLr8G8QNlLaDE07SC2BxtBzu0CUA+3jmfFU9hW16iQDTVE9 hD5lH72Pwjzch6DyiGHp/5cfWyrEDR16/U3e0ALs4a5fLnf26TWff9OQg04aD90MVME1 RDV9hrfcOpCIGexly3tThNlU7FZsF9+XLmVzheegGCqVMOhWcJ9MpxdqBnVJYEP0WceP qQ== Received: from aserp3030.oracle.com (aserp3030.oracle.com [141.146.126.71]) by userp2120.oracle.com with ESMTP id 2rj13qpvcv-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Fri, 05 Apr 2019 20:40:18 +0000 Received: from pps.filterd (aserp3030.oracle.com [127.0.0.1]) by aserp3030.oracle.com (8.16.0.27/8.16.0.27) with SMTP id x35KdRUS140991; Fri, 5 Apr 2019 20:40:18 GMT Received: from aserv0122.oracle.com (aserv0122.oracle.com [141.146.126.236]) by aserp3030.oracle.com with ESMTP id 2rp34jjrq8-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Fri, 05 Apr 2019 20:40:18 +0000 Received: from abhmp0009.oracle.com (abhmp0009.oracle.com [141.146.116.15]) by aserv0122.oracle.com (8.14.4/8.14.4) with ESMTP id x35KeFAV015804; Fri, 5 Apr 2019 20:40:15 GMT Received: from [10.159.140.147] (/10.159.140.147) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Fri, 05 Apr 2019 13:40:15 -0700 Subject: Re: [PATCH net v6] failover: allow name change on IFF_UP slave interfaces To: mst@redhat.com, sridhar.samudrala@intel.com, stephen@networkplumber.org, davem@davemloft.net, kubakici@wp.pl, alexander.duyck@gmail.com, jiri@resnulli.us, netdev@vger.kernel.org, virtualization@lists.linux-foundation.org References: <1554267167-17561-1-git-send-email-si-wei.liu@oracle.com> Cc: liran.alon@oracle.com, boris.ostrovsky@oracle.com, vijay.balakrishna@oracle.com From: si-wei liu Organization: Oracle Corporation Message-ID: Date: Fri, 5 Apr 2019 13:40:05 -0700 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:45.0) Gecko/20100101 Thunderbird/45.8.0 MIME-Version: 1.0 In-Reply-To: <1554267167-17561-1-git-send-email-si-wei.liu@oracle.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit X-Proofpoint-Virus-Version: vendor=nai engine=5900 definitions=9218 signatures=668685 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=4 malwarescore=0 phishscore=0 bulkscore=0 spamscore=0 mlxscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1904050137 X-Proofpoint-Virus-Version: vendor=nai engine=5900 definitions=9218 signatures=668685 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 priorityscore=1501 malwarescore=0 suspectscore=4 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 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-1904050137 Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org A gentle reminder. This patch still needs reviewer to acknowledge the change proposed. -Siwei On 4/2/2019 9:52 PM, Si-Wei Liu wrote: > 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 listen for the rename > and/or link down/up events on failover slaves. Userspace component > interacting with slaves is expected to be changed to operate on failover > master interface 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 userspace components should only > deal with failover master in the long run. > > Fixes: 30c8bd5aa8b2 ("net: Introduce generic failover module") > Signed-off-by: Si-Wei Liu > Reviewed-by: Liran Alon > > -- > v1 -> v2: > - Drop configurable module parameter (Sridhar) > > v2 -> v3: > - Drop additional IFF_SLAVE_RENAME_OK flag (Sridhar) > - Send down and up events around rename (Michael S. Tsirkin) > > v3 -> v4: > - Simplify notification to be sent (Stephen Hemminger) > > v4 -> v5: > - Sync up code with latest net-next (Sridhar) > - Use proper structure initialization (Stephen, Jiri) > > v5 -> v6: > - Make the property of live name change a generic flag (Stephen) > --- > include/linux/netdevice.h | 3 +++ > net/core/dev.c | 25 ++++++++++++++++++++++++- > net/core/failover.c | 6 +++--- > 3 files changed, 30 insertions(+), 4 deletions(-) > > diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h > index 78f5ec4e..ea9a63f 100644 > --- a/include/linux/netdevice.h > +++ b/include/linux/netdevice.h > @@ -1498,6 +1498,7 @@ struct net_device_ops { > * @IFF_FAILOVER: device is a failover master device > * @IFF_FAILOVER_SLAVE: device is lower dev of a failover master device > * @IFF_L3MDEV_RX_HANDLER: only invoke the rx handler of L3 master device > + * @IFF_LIVE_NAME_CHANGE: rename is allowed while device is running > */ > enum netdev_priv_flags { > IFF_802_1Q_VLAN = 1<<0, > @@ -1530,6 +1531,7 @@ enum netdev_priv_flags { > IFF_FAILOVER = 1<<27, > IFF_FAILOVER_SLAVE = 1<<28, > IFF_L3MDEV_RX_HANDLER = 1<<29, > + IFF_LIVE_NAME_CHANGE = 1<<30, > }; > > #define IFF_802_1Q_VLAN IFF_802_1Q_VLAN > @@ -1561,6 +1563,7 @@ enum netdev_priv_flags { > #define IFF_FAILOVER IFF_FAILOVER > #define IFF_FAILOVER_SLAVE IFF_FAILOVER_SLAVE > #define IFF_L3MDEV_RX_HANDLER IFF_L3MDEV_RX_HANDLER > +#define IFF_LIVE_NAME_CHANGE IFF_LIVE_NAME_CHANGE > > /** > * struct net_device - The DEVICE structure. > diff --git a/net/core/dev.c b/net/core/dev.c > index 9823b77..48341d5 100644 > --- a/net/core/dev.c > +++ b/net/core/dev.c > @@ -1185,7 +1185,21 @@ 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) > + > + /* Some auto-enslaved devices e.g. failover slaves are > + * special, as userspace might rename the device after > + * the interface had been brought up and running since > + * the point kernel initiated auto-enslavement. Allow > + * live name change even when these slave devices are > + * up and running. > + * > + * Typically, users of these auto-enslaving devices > + * don't actually care about slave name change, as > + * they are supposed to operate on master interface > + * directly. > + */ > + if (dev->flags & IFF_UP && > + likely(!(dev->priv_flags & IFF_LIVE_NAME_CHANGE))) > return -EBUSY; > > write_seqcount_begin(&devnet_rename_seq); > @@ -1232,6 +1246,15 @@ int dev_change_name(struct net_device *dev, const char *newname) > hlist_add_head_rcu(&dev->name_hlist, dev_name_hash(net, dev->name)); > write_unlock_bh(&dev_base_lock); > > + if (unlikely(dev->flags & IFF_UP)) { > + struct netdev_notifier_change_info change_info = { > + .info.dev = dev, > + }; > + > + call_netdevice_notifiers_info(NETDEV_CHANGE, > + &change_info.info); > + } > + > ret = call_netdevice_notifiers(NETDEV_CHANGENAME, dev); > ret = notifier_to_errno(ret); > > diff --git a/net/core/failover.c b/net/core/failover.c > index 4a92a98..b5cd3c7 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_LIVE_NAME_CHANGE); > > 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_LIVE_NAME_CHANGE); > 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_LIVE_NAME_CHANGE); > > if (fops && fops->slave_unregister && > !fops->slave_unregister(slave_dev, failover_dev))