This started as a sub-project of QDirStat, but it turned out that this may be useful in general, and it would be too dangerous and too error-prone to offer it directly in the QDirStat GUI. Things can easily go wrong, there may be many pathological situations, and many operations require root permissions; not anything a GUI program should rely upon.

Problem

If files are shadowed by a mount, they are invisible, yet they still occupy disk space.

For example, if your root filesystem contains an existing directory /home/kilroy with 2 GB worth of files, but you also have a separate /home filesystem that has an /etc/fstab entry, that separate /home fileystem is mounted over those files in /home/kilroy, making those 2 GB invisible and unaccessible, no matter if the separate /home also has a /home/kilroy directory. Of course those shadowed files still occupy disk space; you just can't see them.

More Details + Solution(s)

• Document
• Script

This is mostly a documentation project, but the idea is to also provide a script (or two) of the most common scenario: Files on the root filesystem shadowed by a mount.

Status

• Doc complete
• Script feature-complete
• Script tested on a recent Tumbleweed VM with a Btrfs root filesystem and a separate /home
• Script tested on a fairly complex setup on Ubuntu 18.04 LTS

Contributions

Some more testing in more scenearios would be nice.

But don't blame me if you wreck your system with it. ;-)

Read the docs carefully!