Re: add a new test for racing AIO COW writes V2

[Christoph Hellwig <hch@lst.de>]

On Mon, Oct 09, 2017 at 03:18:33PM +0800, Eryu Guan wrote:
> On Wed, Oct 04, 2017 at 08:16:16AM +0200, Christoph Hellwig wrote:
> > This can be used to trigger an assert in the current XFS code because it
> > can't handle the case where there are COW extents on a file, but none
> > at or below the range converted by the AIO completion handler.
> > 
> > Signed-off-by: Christoph Hellwig <hch@lst.de>
> 
> I fixed several minor issues on commit (see inline comments).
> 
> I haven't reproduced the assert failure yet on my test vm, but as the
> commit log in v1 patch, it's not 100% reproducible, maybe I'm just lucky
> (or not lucky :)

Hmm, I only got 1 non-reproduce out of about 100 runs.  Maybe your
device is too fast, as this was in a VM.