On Fri, Apr 03, 2009 at 02:09:54AM +0100, Al Viro wrote: > On Fri, Apr 03, 2009 at 12:18:59AM +0100, Al Viro wrote: > > > Eww... Let's not. First of all, the really useful part of nd->root for > > normal case is that it allows to get ...->fs->root once. So it's better > > to *cache* ->fs->root in there. At which point the flag disappears, > > since it becomes simply nd->root.mnt != NULL. > > > > The interesting part is keeping refcounting happy. I'll see how to do > > that - it's clearly useful on its own. Hopefully will post later tonight... > > ... and the ugly part is the check in follow_dotdot() - one about crossing > out of chroot. Joy... OK, that's actually doable. See git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6.git/ cache-root for current variant; it's for comments *only* - not for merge. After that one we should be able to do a modified variant of e.g. vfs_path_lookup() that would do get_path(root); nd->root = root; instead of nd->root.mnt = NULL; and have lookup with root set to given place without touching current->fs at all. Warning: this is completely untested. Not even "does it boot?", just a code dump. -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
