On Tue, 12 Dec 2023 at 10:35, Christian Brauner <brauner@xxxxxxxxxx> wrote: > So taking a step back here, please. The original motivation for this > discussion was restricted to handle btrfs - and now bcachefs as well. > Both have a concept of a subvolume so it made sense to go that route. > IOW, it wasn't originally a generic problem or pitched as such. > > Would overlayfs be able to utilize an extended inode field as well? Well, yes, but I don't think that's the right solution. I think the right solution is to move to using file handles instead of st_ino, the problem with that is that there's no way kernel can force upgrading userspace. It might help to have the fh in statx, since that's easier on the userspace programmer than having to deal with two interfaces (i_ino won't go away for some time, because of backward compatibility). OTOH I also don't like the way it would need to be shoehorned into statx. Thanks, Miklos
