From: "Mahesh Bandewar (महेश बंडेवार)" <maheshb@google.com>
To: Jay Vosburgh <jay.vosburgh@canonical.com>
Cc: Andy Gospodarek <andy@greyhouse.net>,
Veaceslav Falico <vfalico@gmail.com>,
David Miller <davem@davemloft.net>,
Netdev <netdev@vger.kernel.org>,
Mahesh Bandewar <mahesh@bandewar.net>
Subject: Re: [PATCH net] bonding: fix active-backup transition after link failure
Date: Wed, 11 Dec 2019 12:10:43 -0800 [thread overview]
Message-ID: <CAF2d9jhg1jb1=AKzYNDC2bu43zx8Ob-exDxk6190LKZnPBDaqQ@mail.gmail.com> (raw)
In-Reply-To: <CAF2d9jgjeky0eMgwFZKHO_RLTBNstH1gCq4hn1FfO=TtrMP1ow@mail.gmail.com>
On Mon, Dec 9, 2019 at 10:41 AM Mahesh Bandewar (महेश बंडेवार)
<maheshb@google.com> wrote:
>
> On Sat, Dec 7, 2019 at 2:09 PM Jay Vosburgh <jay.vosburgh@canonical.com> wrote:
> >
> > Mahesh Bandewar <maheshb@google.com> wrote:
> >
> > >After the recent fix 1899bb325149 ("bonding: fix state transition
> > >issue in link monitoring"), the active-backup mode with miimon
> > >initially come-up fine but after a link-failure, both members
> > >transition into backup state.
> > >
> > >Following steps to reproduce the scenario (eth1 and eth2 are the
> > >slaves of the bond):
> > >
> > > ip link set eth1 up
> > > ip link set eth2 down
> > > sleep 1
> > > ip link set eth2 up
> > > ip link set eth1 down
> > > cat /sys/class/net/eth1/bonding_slave/state
> > > cat /sys/class/net/eth2/bonding_slave/state
> > >
> > >Fixes: 1899bb325149 ("bonding: fix state transition issue in link monitoring")
> > >CC: Jay Vosburgh <jay.vosburgh@canonical.com>
> > >Signed-off-by: Mahesh Bandewar <maheshb@google.com>
> > >---
> > > drivers/net/bonding/bond_main.c | 3 ---
> > > 1 file changed, 3 deletions(-)
> > >
> > >diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
> > >index fcb7c2f7f001..ad9906c102b4 100644
> > >--- a/drivers/net/bonding/bond_main.c
> > >+++ b/drivers/net/bonding/bond_main.c
> > >@@ -2272,9 +2272,6 @@ static void bond_miimon_commit(struct bonding *bond)
> > > } else if (BOND_MODE(bond) != BOND_MODE_ACTIVEBACKUP) {
> > > /* make it immediately active */
> > > bond_set_active_slave(slave);
> > >- } else if (slave != primary) {
> > >- /* prevent it from being the active one */
> > >- bond_set_backup_slave(slave);
> >
> > How does this fix things? Doesn't bond_select_active_slave() ->
> > bond_change_active_slave() set the backup flag correctly via a call to
> > bond_set_slave_active_flags() when it sets a slave to be the active
> > slave? If this change resolves the problem, I'm not sure how this ever
> > worked correctly, even prior to 1899bb325149.
> >
> Hi Jay, I used kprobes to figure out the brokenness this patch fixes.
> Prior to your patch this call would not happen but with the patch,
> this extra call will put the master into the backup mode erroneously
> (in fact both members would be in backup state). The mechanics you
> have mentioned works correctly except that in the prior case, the
> switch statement was using new_link which was not same as
> link_new_state. The miimon_inspect will update new_link which is what
> was used in miimon_commit code. The link_new_state was used only to
> mitigate the rtnl-lock issue which would update the "link". Hence in
> the prior code, this path would never get executed.
>
> The steps to reproduce this issue is straightforward and happens 100%
> of the time (I used two mlx interfaces but that shouldn't matter).
>
A friendly ping.
> thanks,
> --mahesh..
> > -J
> >
> > > }
> > >
> > > slave_info(bond->dev, slave->dev, "link status definitely up, %u Mbps %s duplex\n",
> > >--
> > >2.24.0.393.g34dc348eaf-goog
> > >
> >
> > ---
> > -Jay Vosburgh, jay.vosburgh@canonical.com
next prev parent reply other threads:[~2019-12-11 20:11 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-06 23:44 [PATCH net] bonding: fix active-backup transition after link failure Mahesh Bandewar
2019-12-07 22:09 ` Jay Vosburgh
2019-12-09 18:41 ` Mahesh Bandewar (महेश बंडेवार)
2019-12-11 20:10 ` Mahesh Bandewar (महेश बंडेवार) [this message]
2019-12-12 6:38 ` Jay Vosburgh
2019-12-12 18:28 ` Mahesh Bandewar (महेश बंडेवार)
2019-12-13 20:28 ` Jay Vosburgh
2019-12-15 0:29 ` Jakub Kicinski
2019-12-15 20:18 ` Mahesh Bandewar (महेश बंडेवार)
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