I want is to mount bind / somewhere else (for example on /tmp/chroot/host_root) such that any submount of / is present and automatically maintained up to date with the mounts in /. For example if I mount something in /mnt I want the same thing automatically available on /tmp/chroot/host_root/mnt too.
mount -o bind does not work of course, because it does not mount recursively all submounts. mount -o rbind mounts every submounts but does not automatically update the mounts (I guess that rbind is not really something the kernel understand, it is just that mount will recursively mount bind every submount). A symlink would work, but as you can guess, I want to access the root of the host system from within a chroot, so a symlink is obviously not the solution.
Is there a way to do what I want? (I’m sure I could write a daemon doing the job, but I want a simple solution, ideally something native to the linux kernel)
