On Thu, 29 Jul 2021 at 07:27, Amir Goldstein <amir73il@xxxxxxxxx> wrote: > Given that today, subvolume mounts (or any mounts) on the lower layer > are not followed by overlayfs, I don't really see the difference > if mounts are created manually or automatically. > Miklos? Never tried overlay on btrfs. Subvolumes AFAIK do not use submounts currently, they are a sort of hack where the st_dev changes when crossing the subvolume boundary, but there's no sign of them in /proc/mounts (there's no d_automount in btrfs). Thanks, Miklos