Re: [patch] s_maxbytes handling

[Stephen C. Tweedie]

Hi,

On Tue, May 22, 2001 at 04:05:14PM +0100, Alan Cox wrote:

> > The s_maxbytes logic is different from the
> > MAX_NON_LFS logic:
> >         if ( pos + count > MAX_NON_LFS && !(file->f_flags&O_LARGEFILE)) {
> >                 if (pos >= MAX_NON_LFS) {
> >                         send_sig(SIGXFSZ, current, 0);
> >                         goto out;
> >                 }

> The spec says of write
>      [EFBIG]
>           The file is a regular file, nbyte is greater than 0 and the
>           starting position is greater than or equal to the offset
>           maximum established in the open file description associated
>           with fildes.
> 
> Which seems to say to me that if we write > 0 bytes and we start at or
> on the boundary we should error - which would agree with your change.

SuS also states

  If a write() requests that more bytes be written than there is room
  for (for example, the ulimit or the physical end of a medium), only as
  many bytes as there is room for will be written. For example, suppose
  there is space for 20 bytes more in a file before reaching a limit. A
  write of 512 bytes will return 20. The next write of a non-zero number
  of bytes will give a failure return (except as noted below)  and the
  implementation will generate a SIGXFSZ signal for the thread.

so SIGXFSZ plus -EFBIG returned would appear to be the correct
behaviour.  That's certainly what 2.2 used to when it encountered such
limits.

Cheers,
 Stephen