It used to happen on Linux with tmpfs, but kernel doesn't allow it anymore: https://web.git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=2a

It used to happen on Linux with tmpfs, but kernel doesn't allow it anymore: https://web.git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=2adc376c551943a07170cbe70f43e6d6065f8906 https://web.git.kernel.org/pub/scm/linux/kernel/git/torvalds... It turns out that glibc readdir() assumes inode zero doesn't happen and the files are "invisible" to anything using libc. But you can call getdents() directly and see them. I actually ran into this on a production machine once a few years ago, a service couldn't restart because a directory appeared to be "stuck" because it had one of these invisible zero inode files in it. It was very amusing, I figured it out by spotting the invisible filename in the strace output from getdents().