On Wed, May 16, 2018 at 08:56:38AM -0700, Darrick J. Wong wrote:
> On Wed, May 16, 2018 at 08:51:46AM -0700, Christoph Hellwig wrote:
> > On Wed, May 16, 2018 at 08:50:00AM -0700, Darrick J. Wong wrote:
> > > > Hey, Darrick, I noticed this while writing up a generic xfstest to test
> > > > that the Btrfs swap support patches don't allow a swapfile with holes.
> > > > It'd be nice if we were all consistent :) This is based on
> > > > xfs-linux/for-next. Feel free to fold it in to your patch or apply it
> > > > separately as you see fit. Thanks!
> > >
> > > I sent a testcase of my own ("generic: test swapfile creation,
> > > activation, and deactivation") a while back; would you mind sending out
> > > yours so we can combine them into a single testcase?
Sure thing, I have a small pile of tests. I'm still working on some
Btrfs-specific ones, but I can send out the generic ones and we can
figure out how to merge them.
> > Wasn't the desire to support holes the rationale for the Aleksei
> > version of the iomap swapfile patch?
>
> Ah, so it was. FWIW I'm not sure why you'd /want/ a holey swapfile?
>From reading the old thread, it looks like Aleksei just wanted
fallocated swap files to work: "I've traced the problem to bmap(), used
in generic_swapfile_activate call, which returns 0 for blocks inside
holes created by fallocate". Are holes in that sense are different from
actual holes in the iomap sense?
