xfs_io bmap confused

[Christoph Hellwig]

On Wed, Jul 08, 2015 at 12:01:53AM -0700, Ming Lin wrote:
> Hi list,
> 
> I am testing some direct-io patches.
> xfs_tests/xfs/080 failed.
> 
> It's strange.
> There is no hole in "rwtest.file",
> but when read it at some offset it returns zero because of hole.
> 
> root at block:~# xfs_io -c bmap /mnt/test/rwtest.file
> /mnt/test/rwtest.file:
>              0: [0..125671]: 160..125831

Sounds like you see an unwritten extent.  What does xfs_bmap -pv show on
the file?