Re: [PATCH] cowlinks v2

Pavel Machek
2004-04-05T11:43:21Z

Hi!

> > And it looks like Pavel already found the solution. Whenever doing
> > something fishy that would confuse the page cache, we
> > 1. lock
> > 2. invalidate page cache for all files belonging to that cow entity
> > 3. copyfile(), write(), or whatever
> > 4. unlock
> >
> > This is always possibly, because page cache for cow-files is never
> > read-write. If it was, we would have done 1-4 before and now have a
> > regular (non-cow) file.
> >
> > Did I miss something?
>
> I know a writable mmap needs to trigger a copy in that case.
> And then are fun cases with MAP_FIXED which may mean invalidation
> is not allowed.

How is "invalidation not allowed" for MAP_FIXED? Application will
never see the fault...

Pavel
--
Horseback riding is like software...
...vgf orggre jura vgf serr.