Re: Update of file offset on write() etc. is non-atomic with I/O

[Al Viro]

On Mon, Mar 03, 2014 at 11:39:02PM +0000, Al Viro wrote:
> On Mon, Mar 03, 2014 at 03:23:55PM -0800, Linus Torvalds wrote:
> 
> > This just uses a "flags" field, and we currently only have two bits
> > that we use: FDPUT_FPUT and FDPUT_POS_UNLOCK. The first patch knows
> > that "fget_light()" writes 0/1 for that, which is the same as the
> > FDPUT_FPUT bit. I didn't bother to comment on it or clean it up, since
> > the second patch just removes that whole fget_light() mess.
> > 
> > Comments?
> 
> do_sendfile() is also there and this one is even more unpleasant ;-/
> We probably can ignore that one (until POSIX learns of its existence),
> thouhg...

OK, other than read/write/readv/writev/lseek we have only sendfile{,64} and
splice; everything else either deals with struct file that is guaranteed to
be not accessible by any syscall (e.g. coredump code) or is not a regular
file.  So the only question is whether we care for syscalls that are
out of scope for POSIX.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/