Could we get an IOCB_NO_READ_HOLE?

Hi Christoph,

Would it be possible to get an IOCB_NO_READ_HOLE flag that causes a read to
either fail entirely if there's a hole in the file or to stop at the hole,
possibly returning -ENODATA if the hole is at the front of the file?

Looking at iomap_dio_iter(), IOMAP_HOLE should be enabled in
iomap_iter::iomap.type for this?  Is it that simple?

David