Re: [RFT PATCH] Delay netroot mounting by 1 second

[Warren Togami <wtogami-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>]

On 06/19/2009 12:19 PM, David Dillow wrote:
> On Fri, 2009-06-19 at 11:08 -0500, Victor Lowther wrote:
>> Or you can include ethtool and check every half second until a timeout
>> to see if the link is back.
>
> With most switches, you'll get a link back almost immediately, but it
> will be in blocking mode and won't transmit your packets for 20-30
> seconds.

Our test suite can simulate this by using attaching qemu's -net tap 
device to a bridge to talk to the other virtual machine instead of using 
-net socket mcast mode.

qemu -net 
tap[,vlan=n][,name=name][,fd=h][,ifname=name][,script=file][,downscript=dfile]

script=can be a script that tells it to attach to a particular bridge.

#!/bin/sh
export PATH=/sbin:/usr/sbin:$PATH
BRIDGEDEV=br0
ifconfig $1 0.0.0.0 up
brctl addif ${BRIDGEDEV} $1

brctl setfd <bridge> <time> sets the bridge’s ’bridge forward delay’ to 
<time> seconds.

Then you can use brctl to make the bridge's forward delay super long.

Warren Togami
wtogami-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org
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