> > > the change you checked in isn't quite correct, though.
> > > if someone does a physio write (via vnd) to an NFS file from a mapping of
> > > the same file at a different offset, you'd set PG_NEEDCOMMMIT on the
> > > pages from the mapping instead of the pages for the range being modified
> > > (which might not even exist on the client).
> > 
> > i see.  so, adding check of pg->offset is enough?
> 
> it looks like that would take care of it, yea.
> (and on second thought, physio would take a different path and avoid
> any problem here, but writes via a vnd block device would still need this.)

physio via /dev/drum has the same problem, hasn't it?

> it would be easier to tell that the nfs_strategy() code is correct if it were
> told more explicitly when it's ok to use the commit mechanism, though.

do you think that B_PAGEIO can be useful for something other than nfs?
if not, isn't it better to push such knowledges into nfs itsself?

YAMAMOTO Takashi