Possible mtu bug in vlan or bce

[Tom Judge]

Hi,

I have seen some strange behaviour today with VLAN interfaces on bce 
interfaces.  I am running 6.2 Release on i386.

I have a bce interface setup on a gig-e network with an MTU of 8192 i 
attach a vlan interface to this and chnage the vlan if mtu to 1500 as it 
has 100Mbit devices on it.  This does not seem to affect the MTU of the 
bce interface, the VLAN mtu is reported as changed by if config but the 
bce is not reported as changed.  However I then start to get error 
messages saying that the NFS server is not responding as it is sending 
packets larger than 1500 bytes.


If I try to raise the mtu of the vlan interface (to 8192 which is the 
value that ifconfig reports for bce0) at this stage ifconfig thows an 
error saying that the value is incorrect.  If I then 'raise' (it already 
appears to be set to 8192 according to ifconfig) the mtu of bce0 to 8192 
and then set the vlan interface mtu to 8192 the nfs server starts to 
work again.


Is this a know bug/problem or should I raise a PR?

Thanks

Tom