Re: [PATCH] new system call mknod64

viro
2003-04-21T18:47:21Z

On Mon, Apr 21, 2003 at 07:47:49PM +0100, Christoph Hellwig wrote:
> On Mon, Apr 21, 2003 at 11:44:59AM -0700, Linus Torvalds wrote:
> > We HAVE to do the mapping somewhere. Old applications only use the lower
> > 16 bits, and that's just something that MUST NOT be broken.
> >
> > The question is only _where_ (not whether) we do the mapping. Right now we
> > keep "dev_t" in teh same format as we give back to user space, and thus we
> > always map into that format internally. But we don't have to: we can have
> > an internal format that is different from the one we show users.
>
> Why do we need to do a mapping? Old applications just won't see the
> high bits (they're mapped to whatever overflow value) - values that
> fit into the old 16bit range should never be remapped.

Why? Whenever we deal with fs code, we _do_ map anyway (bytesex, if nothing
else). Ditto for any network filesystems.

Let's go for 32:32 internal and simply map upon mknod(2) and friends.
On the syscall boundary. End of problem.