ethtool not available in post-ifup script

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SRU Justification:

1. Impact: users who have /usr on a separate, remote, slow filesystem, may find that ethtool does not exist when ethtool's ifup.d rules fire.
2. How bug was addressed: ethtool was moved from /usr/sbin to /sbin
3. Minimal patch: http://bazaar.launchpad.net/~ubuntu-branches/ubuntu/maverick/ethtool/maverick/revision/12
4. To reproduce: put /usr on a slow (i.e. remote NFS mounted) filesystem, install ethtool on a system using it.
5. Regression potential: This fix has been applied in maverick and natty with no ill effects. If users have custom scripts calling /usr/sbin/ethtool by its full path, those might now fail since we do not provide an automatic link.

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Binary package hint: ethtool

PROBLEM:

I am running Ubuntu 8.04 in a Xen DomU.

To fix network performance issues, the line "post-up /usr/sbin/ethtool -K eth0 tx off" is needed for the virtual ethernet device within the /etc/network/intefaces file.

Usually this works fine, however if /usr is stored on its own partition this command fails, as /usr is not yet mounted when udev executes ifup for the ethernet device.

Unfortunately this causes some very strange errors like "/etc/init.d/networking stop" to fail bacause the eth0 interface is brought up but not correctly registered in the state file.

The only workaround at the moment is to disable the ifup / ifdown hooks in /etc/udev/rules.d/85-ifupdown.rules.

PROPOSED SOLUTION:

The best solution would be moving /usr/sbin/ethtool to /sbin/ethtool so that it is available on startup before /usr has been mounted.