[PATCH master] fs: align truncate return codes with POSIX

[Marco Felsch]

Hi Ahmad,

thanks for the patch.

On 23-02-02, Ahmad Fatoum wrote:
> Writing past end of a file results in a cryptic error code:
> 
>   barebox at board:/ cp /dev/zero /dev/mmc0.part
>   write: Operation not permitted
>   cp: Operation not permitted
> 
> Because the cdev's truncate is not implemented and as such partition
> can't be increased in size. POSIX specifies EPERM as the correct return
> code for truncate(2) in such a situation, but for write(2) it is ENOSPC.
> Thus most truncate callbacks in barebox instead return ENOSPC, when
> according to POSIX, EPERM would have been the correct error code to
> propagate.
> 
> Switching all truncate drivers is a bit more involved, so for now let's
> treat EPERM and ENOSPC instead when truncate fails to enlarge a file.
> 
> Reported-by: Marco Felsch <m.felsch at pengutronix.de>
> Signed-off-by: Ahmad Fatoum <a.fatoum at pengutronix.de>

Reviewed-by: Marco Felsch <m.felsch at pengutronix.de>