Function owned_mounts 

pub fn owned_mounts(
    namespace: &[ContainerMount],
    installations: &[Installation],
) -> (BTreeSet<u64>, BTreeSet<u64>)

The rows of namespace the installations made, split into Hermit’s (the plan’s own: rule 1 of ContainerMountTable::select) and a backend’s own. A created row counts only at, or below, a mountpoint its installation names, so no row a later mount’s symbolic link redirects a path onto can be taken for an installation’s. A recursive bind’s copy of a mount below its source takes the owner of the row it copies: a backend’s own mount staged below Hermit’s private tmp directory stays a backend’s in the bind of that directory over /tmp.