nullfs?

Posted Feb 14, 2026 12:50 UTC (Sat) by zhalas (subscriber, #114013)
In reply to: nullfs? by chexo4
Parent article: The first half of the 7.0 merge window

> I’m confused what the point of nullfs is. I thought most init scripts worked by doing pivot root already anyway, why would you need to clean up the initramfs in that case?

pivot_root does not work on rootfs, (see: https://man7.org/linux/man-pages/man2/pivot_root.2.html):

> EINVAL The current root is on the rootfs (initial ramfs) mount;
> see NOTES.

> The rootfs (initial ramfs) cannot be pivot_root()ed. The
> recommended method of changing the root filesystem in this case is
> to delete everything in rootfs, overmount rootfs with the new
> root, attach stdin/stdout/stderr to the new /dev/console, and exec
> the new init(1). Helper programs for this process exist; see
> switch_root(8).
```

see: https://man7.org/linux/man-pages/man2/pivot_root.2.html