On Thu, 2019-02-07 at 12:57 -0800, Evan Green wrote:

Properly plumb out EOPNOTSUPP from loop driver operations, which may
get returned when for instance a discard operation is attempted but not
supported by the underlying block device. Before this change, everything
was reported in the log as an I/O error, which is scary and not
helpful in debugging.

Reviewed-by: Bart Van Assche <bvanassche@acm.org>