Re: NetBSD 5.1_RC1/amd64 domU: xbdback backend/vbd/3/1: DIOCCACHESYNC returned 25

[Jean-Yves Migeon <jeanyves.migeon%free.fr@localhost>]

On Tue, 11 May 2010 13:25:02 +0100, Hugo Silva <hugo%barafranca.com@localhost> 
wrote:
> Hello list,
> 
> dom0: NetBSD 5.99.29 amd64
> 
> As soon as I start my lvm-backed domU running 5.1_RC1, dom0's kernel 
> message buffer is filled with:
> 
> xbdback backend/vbd/3/1: DIOCCACHESYNC returned 25
> 
> This goes on for as long as the domU is up.
> 
> Booting this domU with a 5.0.2 kernel doesn't produce this behaviour.
> 
> Anyone else experiencing the same?

dm(4) does not implement DIOCCACHESYNC ioctl(), so it returns ENOTTY for
your lvm backend in dom0.

As DIOCCACHESYNC was pulled-up to NetBSD-5, the dom0 logs the error as it
is not supported when domU requests this operation.

I am not familiar enough with lvm to know how this could be implemented
though :/

-- 
Jean-Yves Migeon
jeanyves.migeon%free.fr@localhost