Coda File System

Re: venus-kernel interface

From: Jan Harkes <>
Date: Thu, 30 Sep 2004 15:34:19 -0400
On Thu, Sep 30, 2004 at 06:39:12PM +0200, Ivan Popov wrote:
> On Thu, Sep 30, 2004 at 11:18:29AM -0400, Jan Harkes wrote:
> >     pioctl opens a magic file /coda/.CONTROLPIPE
> >     venus returns an open socket or pipe.
>  ...
> Hello Jan,
> glad you find it interesting.
> If I am not totally off, you considering the communication between
> other processes and Venus. I thought also about the kernel-Venus
> communication. Now it is ioctl()s which is quite natural,
> but can break when ioctls are remapped by an unaware abi-compatibility
> layer.

Nope, kernel-venus protocol already uses simple read and write syscalls
on the /dev/cfs0 device. The problem is when an application like clog
tries to pass something to venus, it uses an ioctl, which the kenrel
module then relays to venus as a CODA_PIOCTL upcall.

Received on 2004-09-30 15:36:45