[3.19.y-ckt stable] Patch "bonding: correctly handle bonding type change on enslave failure" has been added to staging queue

[Kamal Mostafa]

This is a note to let you know that I have just added a patch titled

    bonding: correctly handle bonding type change on enslave failure

to the linux-3.19.y-queue branch of the 3.19.y-ckt extended stable tree 
which can be found at:

    http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-3.19.y-queue

This patch is scheduled to be released in version 3.19.8-ckt6.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.19.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

------

>From d97186a400129cf7e93d388e4b38edacca71c639 Mon Sep 17 00:00:00 2001
From: Nikolay Aleksandrov <nikolay at cumulusnetworks.com>
Date: Wed, 15 Jul 2015 22:57:01 +0200
Subject: bonding: correctly handle bonding type change on enslave failure

commit 7d5cd2ce5292b45e555de776cb9e72975a07460d upstream.

If the bond is enslaving a device with different type it will be setup
by it, but if after being setup the enslave fails the bond doesn't
switch back its type and also keeps pointers to foreign structures that can
be long gone. Thus revert back any type changes if the enslave failed and
the bond had to change its type.
Example:
 Before patch:
$ echo lo > bond0/bonding/slaves
-bash: echo: write error: Cannot assign requested address
$ ip l sh bond0
20: bond0: <BROADCAST,MULTICAST,MASTER> mtu 1500 qdisc noop state DOWN
mode DEFAULT group default
    link/loopback 16:54:78:34:bd:41 brd 00:00:00:00:00:00
$ echo +eth1 > bond0/bonding/slaves
$ ip l sh bond0
20: bond0: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN mode
DEFAULT group default qlen 1000
    link/ether 52:54:00:3f:47:69 brd ff:ff:ff:ff:ff:ff
(notice the MASTER flag is gone)

 After patch:
$ echo lo > bond0/bonding/slaves
-bash: echo: write error: Cannot assign requested address
$ ip l sh bond0
21: bond0: <BROADCAST,MULTICAST,MASTER> mtu 1500 qdisc noop state DOWN
mode DEFAULT group default qlen 1000
    link/ether 6e:66:94:f6:07:fc brd ff:ff:ff:ff:ff:ff
$ echo +eth1 > bond0/bonding/slaves
$ ip l sh bond0
21: bond0: <BROADCAST,MULTICAST,MASTER> mtu 1500 qdisc noop state DOWN
mode DEFAULT group default qlen 1000
    link/ether 52:54:00:3f:47:69 brd ff:ff:ff:ff:ff:ff

Signed-off-by: Nikolay Aleksandrov <nikolay at cumulusnetworks.com>
Fixes: e36b9d16c6a6 ("bonding: clean muticast addresses when device changes type")
Signed-off-by: David S. Miller <davem at davemloft.net>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 drivers/net/bonding/bond_main.c | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
index 68ad39a..19186bf 100644
--- a/drivers/net/bonding/bond_main.c
+++ b/drivers/net/bonding/bond_main.c
@@ -1617,9 +1617,16 @@ err_free:

 err_undo_flags:
 	/* Enslave of first slave has failed and we need to fix master's mac */
-	if (!bond_has_slaves(bond) &&
-	    ether_addr_equal_64bits(bond_dev->dev_addr, slave_dev->dev_addr))
-		eth_hw_addr_random(bond_dev);
+	if (!bond_has_slaves(bond)) {
+		if (ether_addr_equal_64bits(bond_dev->dev_addr,
+					    slave_dev->dev_addr))
+			eth_hw_addr_random(bond_dev);
+		if (bond_dev->type != ARPHRD_ETHER) {
+			ether_setup(bond_dev);
+			bond_dev->flags |= IFF_MASTER;
+			bond_dev->priv_flags &= ~IFF_TX_SKB_SHARING;
+		}
+	}

 	return res;
 }
--
1.9.1