Re: [PATCH] namespace.c: fix bind mount from foreign namespace

[Al Viro <viro@parcelfarce.linux.theplanet.co.uk>]

On Fri, May 13, 2005 at 07:17:39PM +0200, Miklos Szeredi wrote:
> > > Bind mount from a foreign namespace results in
> > 
> > ... -EINVAL
> 
> Wrong answer.  Look again, you wrote the code, so you _should_ know ;)

static inline int check_mnt(struct vfsmount *mnt)
{
        return mnt->mnt_namespace == current->namespace;
}

static int do_loopback(struct nameidata *nd, char *old_name, int recurse)
{
        struct nameidata old_nd;
        struct vfsmount *mnt = NULL;
	/* no changes of mnt */
	err = -EINVAL;
	if (check_mnt(nd->mnt) && ... ) {
		/* assigns to mnt */
	}
	if (mnt) {
		/* assigns to err */
	}
        up_write(&current->namespace->sem);
        path_release(&old_nd);
        return err;
}

Care to explain how that would not give -EINVAL?