Re: Hole punching and mmap races

Dave Chinner
2012-05-18T10:12:27Z

On Fri, May 18, 2012 at 01:28:29AM +0200, Jan Kara wrote:
> On Thu 17-05-12 17:43:08, Dave Chinner wrote:
> > On Wed, May 16, 2012 at 03:04:45PM +0200, Jan Kara wrote:
> > > On Wed 16-05-12 12:14:23, Dave Chinner wrote:
> > IIRC, it's a rare case (that I consider insane, BTW): read from a
> > file with into a buffer that is a mmap()d region of the same file
> > that has not been faulted in yet.....
> With punch hole, the race is less insane - just punching hole in the area
> which is accessed via mmap could race in a bad way AFAICS.

Seems the simple answer to me is to prevent page faults while hole
punching, then....

Cheers,

Dave.
--
Dave Chinner
david@fromorbit.com