There&#x27;s OverlayFS.<p>It does exactly what you want, although it was created for different use cases (Live CDs, layered images as used by Docker, etc.):<p><a href="https:&#x2F;&#x2F;git.kernel.org&#x2F;cgit&#x2F;linux&#x2F;kernel&#x2F;git&#x2F;torvalds&#x2F;linux.git&#x2F;tree&#x2F;Documentation&#x2F;filesystems&#x2F;overlayfs.txt" rel="nofollow">https:&#x2F;&#x2F;git.kernel.org&#x2F;cgit&#x2F;linux&#x2F;kernel&#x2F;git&#x2F;torvalds&#x2F;linux....</a>