Re: Could we get an IOCB_NO_READ_HOLE?

On Fri, Sep 17, 2021 at 11:43:59AM +0100, David Howells wrote:

David Howells [off-list ref] wrote:

quoted

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?

Actually, that's not the right thing.  How about the attached - at least for
direct I/O?

This looks pretty reasonable.  We'll just need to make sure to reject
the flag for the many file operations instances that do not support it.