Re: [Nbd] maximum size of a read/write request

[Wouter Verhelst <w@...112...>]

On Mon, Oct 10, 2011 at 03:05:10PM +0200, Paolo Bonzini wrote:
> > That is too tricky: a new kernel version might show differnt
> > behaviour. Imho we should specify a limit or make it configurable or
> > put it in the protocol. We have 124 bytes of handshake left, we can
> > use 8 of them for a maximum blocksize.
> 
> O_DIRECT bypasses everything clever that the kernel might do.

More to the point, O_DIRECT is _defined_ as "don't try to be clever
about this request, just do it". If a new kernel version were to show
different behaviour, that would be a bug in the kernel.

-- 
The volume of a pizza of thickness a and radius z can be described by
the following formula:

pi zz a