Function ensure_dir_labeled_recurse 

pub(crate) fn ensure_dir_labeled_recurse(
    root: &Dir,
    path: &mut Utf8PathBuf,
    policy: &SePolicy,
    skip: Option<(dev_t, ino64_t)>,
) -> Result<()>

Recursively ensure all files under a directory have SELinux labels. Uses the walk API with noxdev and skip_mountpoints to avoid crossing mount point boundaries (e.g. into sysfs, procfs, etc.). The provided skip parameter is a device/inode pair that we will ignore (and not traverse into).