Re: [PATCH 02/10] iomap: improve shared block detection in iomap_unshare_iter

Darrick J. Wong
2024-08-27T16:21:50Z

On Tue, Aug 27, 2024 at 07:47:57AM +0200, Christoph Hellwig wrote:
> On Mon, Aug 26, 2024 at 10:44:24PM -0700, Darrick J. Wong wrote:
> > Maybe we should rename it then?
> >
> > IOMAP_F_OUT_OF_PLACE_WRITE.
> >
> > Yuck.
> >
> > IOMAP_F_ELSEWHERE
> >
> > Not much better. Maybe just add a comment that "IOMAP_F_SHARED" really
> > just means an out of place write (aka srcmap is not just a hole).
>
> Heh.
>
> For writes it usually means out of place write, but for reporting
> it gets translated to the FIEMAP_EXTENT_SHARED flag or is used to
> reject swapon. And the there is black magic in DAX.

Hee hee. Yeah, let's leave IOMAP_F_SHARED alone; an out of place write
can be detected by iter->srcmap.type != HOLE.

The patch looks fine so
Reviewed-by: Darrick J. Wong <djwong@kernel.org>

--D