LU-17550 lov: check for empty layout on DIO

LU-17550 lov: check for empty layout on DIO

When a write crosses from an area of a file with a layout to
one without, the write should return ENODATA.  Due to layout
caching in the direct IO path, we need an extra check for
this to work correctly for DIO.

Fixes: 14db1faa0f ("LU-13799 lov: Cache stripe offset calculation")
Signed-off-by: Patrick Farrell <patrick.farrell@oracle.com>
Change-Id: Ib9a40dab7939d9420144ecaa7460625d6184aa0b
Reviewed-on: https://review.whamcloud.com/c/fs/lustre-release/+/54077
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: Shaun Tancheff <shaun.tancheff@hpe.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>