From mboxrd@z Thu Jan 1 00:00:00 1970 From: Nikolay Aleksandrov Subject: Re: [PATCH] bonding: correct the MAC address for "follow" fail_over_mac policy Date: Thu, 16 Jul 2015 11:24:16 +0200 Message-ID: <55A77840.5010506@cumulusnetworks.com> References: <55A76B8A.5040804@huawei.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit To: Ding Tianhong , "j.vosburgh@gmail.com >> Jay Vosburgh" , "vfalico@gmail.com >> Veaceslav Falico" , Andy Gospodarek , Netdev , "David S. Miller" , fengtiantian@huawei.com, "hahaer.guo@huawei.com >> Guozhibin (Hahaer)" Return-path: Received: from mail-wg0-f48.google.com ([74.125.82.48]:35561 "EHLO mail-wg0-f48.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752396AbbGPJYT (ORCPT ); Thu, 16 Jul 2015 05:24:19 -0400 Received: by wgjx7 with SMTP id x7so53295400wgj.2 for ; Thu, 16 Jul 2015 02:24:17 -0700 (PDT) In-Reply-To: <55A76B8A.5040804@huawei.com> Sender: netdev-owner@vger.kernel.org List-ID: On 07/16/2015 10:30 AM, Ding Tianhong wrote: > The "follow" fail_over_mac policy is useful for multiport devices that > either become confused or incur a performance penalty when multiple > ports are programmed with the same MAC address, but the same MAC > address still may happened by this steps for this policy: > > 1) echo +eth0 > /sys/class/net/bond0/bonding/slaves > bond0 has the same mac address with eth0, it is MAC1. > > 2) echo +eth1 > /sys/class/net/bond0/bonding/slaves > eth1 is backup, eth1 has MAC2. > > 3) ifconfig eth0 down > eth1 became active slave, bond will swap MAC for eth0 and eth1, > so eth1 has MAC1, and eth0 has MAC2. > > 4) ifconfig eth1 down > there is no active slave, and eth1 still has MAC1, eth2 has MAC2. > > 5) ifconfig eth0 up > the eth0 became active slave again, the bond set eth0 to MAC1. > > Something wrong here, then if you set eth1 up, the eth0 and eth1 will have the same > MAC address, it will break this policy for ACTIVE_BACKUP mode. > > This patch will fix this problem by finding the old active slave and > swap them MAC address before change active slave. > > Signed-off-by: Ding Tianhong > --- > drivers/net/bonding/bond_main.c | 20 ++++++++++++++++++++ > 1 file changed, 20 insertions(+) > This doesn't seem to be true: ~# cat /sys/class/net/bond0/bonding/fail_over_mac follow 2 root@debian:~# ip l sh eth1 3: eth1: mtu 1500 qdisc pfifo_fast master bond0 state UP mode DEFAULT group default qlen 1000 link/ether 52:54:00:3f:47:69 brd ff:ff:ff:ff:ff:ff root@debian:~# ip l sh eth2 4: eth2: mtu 1500 qdisc pfifo_fast master bond0 state UP mode DEFAULT group default qlen 1000 link/ether 52:54:00:4f:a5:99 brd ff:ff:ff:ff:ff:ff root@debian:~# ip l sh bond0 26: bond0: mtu 1500 qdisc noqueue state UP mode DEFAULT group default link/ether 52:54:00:3f:47:69 brd ff:ff:ff:ff:ff:ff *eth1 is the first and active slave and bond0 has taken its mac. Now trying your steps: Step 3) (bringing down the active eth1) root@debian:~# ip l set eth1 down root@debian:~# ip l sh bond0 26: bond0: mtu 1500 qdisc noqueue state UP mode DEFAULT group default link/ether 52:54:00:3f:47:69 brd ff:ff:ff:ff:ff:ff root@debian:~# ip l sh eth1 3: eth1: mtu 1500 qdisc pfifo_fast master bond0 state DOWN mode DEFAULT group default qlen 1000 link/ether 52:54:00:4f:a5:99 brd ff:ff:ff:ff:ff:ff root@debian:~# ip l sh eth2 4: eth2: mtu 1500 qdisc pfifo_fast master bond0 state UP mode DEFAULT group default qlen 1000 link/ether 52:54:00:3f:47:69 brd ff:ff:ff:ff:ff:ff *The mac addresses of eth1 and eth2 are correctly swapped, so far so good. Step 4) (bringing down the active eth2) root@debian:~# ip l set eth2 down 3: eth1: mtu 1500 qdisc pfifo_fast master bond0 state DOWN mode DEFAULT group default qlen 1000 link/ether 52:54:00:4f:a5:99 brd ff:ff:ff:ff:ff:ff 4: eth2: mtu 1500 qdisc pfifo_fast master bond0 state DOWN mode DEFAULT group default qlen 1000 link/ether 52:54:00:3f:47:69 brd ff:ff:ff:ff:ff:ff 26: bond0: mtu 1500 qdisc noqueue state DOWN mode DEFAULT group default link/ether 52:54:00:3f:47:69 brd ff:ff:ff:ff:ff:ff *eth2 has kept the mac address of the bond and they're both down now Step 5) (bring eth1 up again and observe the macs) ~# ip l set eth1 up 3: eth1: mtu 1500 qdisc pfifo_fast master bond0 state UP mode DEFAULT group default qlen 1000 link/ether 52:54:00:3f:47:69 brd ff:ff:ff:ff:ff:ff 4: eth2: mtu 1500 qdisc pfifo_fast master bond0 state DOWN mode DEFAULT group default qlen 1000 link/ether 52:54:00:4f:a5:99 brd ff:ff:ff:ff:ff:ff 26: bond0: mtu 1500 qdisc noqueue state UP mode DEFAULT group default link/ether 52:54:00:3f:47:69 brd ff:ff:ff:ff:ff:ff *The macs are correctly swapped and there's no such bug. Step 6(?) bring eth2 up ~# ip l set eth2 up 3: eth1: mtu 1500 qdisc pfifo_fast master bond0 state UP mode DEFAULT group default qlen 1000 link/ether 52:54:00:3f:47:69 brd ff:ff:ff:ff:ff:ff 4: eth2: mtu 1500 qdisc pfifo_fast master bond0 state UP mode DEFAULT group default qlen 1000 link/ether 52:54:00:4f:a5:99 brd ff:ff:ff:ff:ff:ff 26: bond0: mtu 1500 qdisc noqueue state UP mode DEFAULT group default link/ether 52:54:00:3f:47:69 brd ff:ff:ff:ff:ff:ff *Still correct. Also the mac address that gets set is dev_addr which is changed when the swapping is done, if you'd like to get the original mac address you should be using slave->perm_hwaddr. Cheers, Nik