RFC: should lseek(SEEK_DATA/SEEK_HOLE) return ENOTTY?

[Alan Somers]

On Sat, Aug 10, 2019 at 8:03 PM Rick Macklem <rmacklem at uoguelph.ca> wrote:
>
> Hi,
>
> I've noticed that, if you do a lseek(SEEK_DATA/SEEK_HOLE) on a file that
> resides in a file system that does not support holes, ENOTTY is returned.
>
> This error isn't listed for lseek() and seems a liitle weird.
>
> I can see a couple of alternatives to this:
> 1 - Return a different error. Maybe ENXIO?
> or
> 2 - Have lseek() do the trivial implementation when the VOP_IOCTL() fails.
>    - For SEEK_DATA, just return the offset given as argument and for SEEK_HOLE
>       return the file's size as the offset.

I vote option 2.

>
> What do others think? rick
> ps: The man page should be updated, whatever is done w.r.t. this.