On 11/9/06, YAMAMOTO Takashi <yamt@mwd.biglobe.ne.jp> wrote:
> > +     /* Flush the vnode if requested. */
> > +     if (obp->b_flags & B_VFLUSH)
> > +             vflushbuf(vp, 0);
> > +
> > +     /* We need to increase the number of outputs on the vnode if
> > +      * there was any write to it (either due to a real write or due
> > +      * to a flush). */
> > +     if (!doread || obp->b_flags & B_VFLUSH)
> > +             vp->v_numoutput++;
>
> can you explain these B_VFLUSH handling?

For the first part I just tried to flush the vnode.  I don't remember
how I ended exactly in vflushbuf, but it *seemed* reasonable...
Hmm... maybe one ought to call VOP_FSYNC instead?  (And maybe this
handles the case below too.)

Aside that, the driver was getting read requests that had the B_VFLUSH
bit active. Later on a "neg numoutput" panic happened which I was able
to fix by incrementing v_numoutput.  Yes, that looks extremely ugly
(at least to me) so, please, if you have any better idea on how to fix
it tell me and I'll take a look.

Thanks.

-- 
Julio M. Merino Vidal <jmmv84@gmail.com>
The Julipedia - http://julipedia.blogspot.com/