Re: pivot_root solved by patch to 2.4.22-pre7

[Rene Mayrhofer <rene.mayrhofer@gibraltar.at>]

Hi all,

The problem with pivot_root that appeared in 2.4.21-ac4 and the 
2.4.22-pre kernels is now solved (at least for my case) by applying the 
trvial patch sent by Jason Baron.

Jason Baron wrote:
> right. so the semantics of how file tables are shared has changed a bit. I
> would think that for at least 'init', it'd be nice to preserve the
> original behavior, for situations such as you described. Something like
> the following would probably work, although i havent' tried the test
> script.
> 
> --- linux/kernel/fork.c.orig  2003-07-23 21:34:59.000000000 -0400
> +++ linux/kernel/fork.c       2003-07-23 21:35:45.000000000 -0400
> @@ -558,7 +558,7 @@ int unshare_files(void)
>  
>         /* This can race but the race causes us to copy when we don't
>            need to and drop the copy */
> -       if(atomic_read(&files->count) == 1)
> +       if(atomic_read(&files->count) == 1 || (current->pid == 1))
>         {
>                 atomic_inc(&files->count);
>                 return 0;
>    



I tried that on my system and it works as expected. The kernel processes
close their fds and the old root fs can thus be unmounted after
pivot_root. Thanks for the hint !
So the problem is solved for me and it would be wonderful to get it into
2.4.22.

best regards,
Rene