Date:	Mon, 15 Aug 2011 12:44:17 +0300
From:	Eduard Sinelnikov <eduard.sinelnikov@...il.com>
To:	netdev@...r.kernel.org, Andy Gospodarek <andy@...yhouse.net>,
	Jay Vosburgh <fubar@...ibm.com>
Subject: Bonding problem

Hi all,

Following the thread:
http://marc.info/?l=linux-netdev&m=131282467512508&w=2

I have created the this patch for kernel version:3.0.1, which may fix
the bonding problem

Patch explanation:
The patch seting all slaves active prior to switching to round robin mode.
This is done to ensure that every posibly active slave will be used in
communication.

Also, I noticed that just changing the bond_xmit_round_robin will only
partially fix the problem.
Since slaves with inactive bit will not CATCH any trafic.

I wonder if I should remove the check "bond_is_active_slave(slave))"
in bond_xmit_round_robin

Please advice.
            Eduard


On Mon, Aug 08, 2011 at 10:06:05AM -0700, Jay Vosburgh wrote:
>
> Andy Gospodarek <andy@...yhouse.net> wrote:
>
> >On Sun, Aug 07, 2011 at 03:00:30PM +0300, Eduard Sinelnikov wrote:
> >> Hi,
> >>
> >> In the kernel 2.6.39.3 ( /drivers/net/bond/bond_main.c).
> >> In the function  ‘bond_xmit_roundrobin’
> >> The code check if the bond is active via
> >> ‘bond_is_active_slave(slave)’ Function call.
> >> Which actually checks if the slave is backup or active
> >> What is the meaning of slave being  backup in round robin mode?
> >> Correct me if I wrong but in round robin every slave should send a
> >> packet, regardless of being active or backup.
> >>
> >> Thank you,
> >> Â  Â  Â  Â  Â  Â Eduard
> >
> >There probably is not a compelling reason to continue to have it.  There
> >may be a reason historically, but I'm not aware what that might be at
> >this point.  For modes other than active-backup, the value of
> >slave->link and slave->backup should always contain a value that
> >indicates the slave is up and available for transmit.
>
> If you read Eduard's other posts regarding this, the actual
> issue is that when changing from another mode into round-robin,
> occasionally slaves will still be marked as "backup" and won't be used:
>

I did notice that one after I sent this first response.

> >Date: Mon, 8 Aug 2011 11:16:39 +0300
> >Subject: On line Bonding configuration change fails
> >From: Eduard Sinelnikov <eduard.sinelnikov@...il.com>
> >To: netdev@...r.kernel.org
> >Sender: netdev-owner@...r.kernel.org
> >
> >Hi,
> >
> >My configuration is a follows:
> >
> >Â  Â  Â  Â  Â  Â  Â | eth0 -------------->
> >Ububntu | eth1 --------------> Â  Â Swith ------------> Other computer
> >
> >Scenario:
> >• change the bond mode to active/backup
> >• unplug some of the cable
> >• plug-in the unplugged cable
> >• change bond mode to round robin
> >
> >I can see that only one eth1 is sending data. When I unplug it the ping stops.
> >
> >Is it a bug or some mis-configuration?
> >
> >In the kernel ( /drivers/net/bond/bond_main.c).
> >In the function  ‘bond_xmit_roundrobin
> >’
> >The code check if the bond is active via
> >‘bond_is_active_slave(slave)’ Function call.
> >Which actually checks if the slave is backup or active
> >What is the meaning of backup in round robin?
> >Correct me if I wrong but in round robin every slave should send a
> >packet, regardless of being active or backup.
>
> So from looking at the code, it seems that the actual problem is
> that when transitioning to round-robin mode, one or more slaves can
> remain marked as "backup," and in round-robin mode, that won't ever
> change.  We could probably work around that by removing the "is_active"
> test (essentially declaring that "is_active" is only valid in
> active-backup mode).  That might produce a few odd messages here and
> there (when removing a slave or during a link failure, for example).
>
> From inspection, the bond_xmit_xor function likely has this same
> problem.
>

Agreed.

> -J
>
> ---
> -Jay Vosburgh, IBM Linux Technology Center, fubar@...ibm.com

Download attachment "bond_patch.patch" of type "application/octet-stream" (1471 bytes)

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