On Tue, Mar 22, 2011 at 09:06:38PM +0100, Miklos Szeredi wrote: > On Tue, 22 Mar 2011, Al Viro wrote: > > Proceeding with rename is not interesting; proceeding with copyup is. > > > > Who said that by the time we get to copy_up_locked you will still have > > dentry (and upper) match lowerpath? Or that ->d_parent on overlay and > > on upper will change in sync, for that matter - there are two d_move() > > calls involved... > > If rename is involved, than rename itself already did the copy up. > And that's checked before proceeding with the actual copy up. If > there was no rename, then that guarantees that things are in sync, at > least for the duration of the copy up. What do you mean, before? It's not atomic... What happens if e.g. you get A: decided to do copy_up_locked blocked on i_mutex B: did copy_up did rename(), complete with d_move() did unlink() in new place A: got CPU back, got i_mutex proceeded to copy lower into new location set dentry to very odd (upper,lower) pair -- 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
