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Message-ID: <55A77840.5010506@cumulusnetworks.com>
Date: Thu, 16 Jul 2015 11:24:16 +0200
From: Nikolay Aleksandrov <nikolay@...ulusnetworks.com>
To: Ding Tianhong <dingtianhong@...wei.com>,
"j.vosburgh@...il.com >> Jay Vosburgh" <j.vosburgh@...il.com>,
"vfalico@...il.com >> Veaceslav Falico" <vfalico@...il.com>,
Andy Gospodarek <gospo@...ulusnetworks.com>,
Netdev <netdev@...r.kernel.org>,
"David S. Miller" <davem@...emloft.net>, fengtiantian@...wei.com,
"hahaer.guo@...wei.com >> Guozhibin (Hahaer)" <hahaer.guo@...wei.com>
Subject: Re: [PATCH] bonding: correct the MAC address for "follow" fail_over_mac
policy
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 <dingtianhong@...wei.com>
> ---
> 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@...ian:~# ip l sh eth1
3: eth1: <BROADCAST,MULTICAST,SLAVE,UP,LOWER_UP> 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@...ian:~# ip l sh eth2
4: eth2: <BROADCAST,MULTICAST,SLAVE,UP,LOWER_UP> 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@...ian:~# ip l sh bond0
26: bond0: <BROADCAST,MULTICAST,MASTER,UP,LOWER_UP> 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@...ian:~# ip l set eth1 down
root@...ian:~# ip l sh bond0
26: bond0: <BROADCAST,MULTICAST,MASTER,UP,LOWER_UP> 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@...ian:~# ip l sh eth1
3: eth1: <BROADCAST,MULTICAST,SLAVE> 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@...ian:~# ip l sh eth2
4: eth2: <BROADCAST,MULTICAST,SLAVE,UP,LOWER_UP> 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@...ian:~# ip l set eth2 down
3: eth1: <BROADCAST,MULTICAST,SLAVE> 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: <BROADCAST,MULTICAST,SLAVE> 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: <NO-CARRIER,BROADCAST,MULTICAST,MASTER,UP> 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: <BROADCAST,MULTICAST,SLAVE,UP,LOWER_UP> 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: <BROADCAST,MULTICAST,SLAVE> 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: <BROADCAST,MULTICAST,MASTER,UP,LOWER_UP> 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: <BROADCAST,MULTICAST,SLAVE,UP,LOWER_UP> 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: <BROADCAST,MULTICAST,SLAVE,UP,LOWER_UP> 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: <BROADCAST,MULTICAST,MASTER,UP,LOWER_UP> 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
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