Hello, World!

Abstract

Don’t read the docs. Read the source!

The issue with docs is often they go stale, unlike source which IS the moving target. A program should do what it says, and if what it says is 20 versions behind… Well, it’s lying to you.

Scripting is unforgiving

It simply discards the exit code which I found out the hard way; when my code (from a running fedora install) tried to create /swap/swapfile inside a subvolume.

You can reproduce it simply without ever needing to even have a btrfs FS. Or to be running a scripted installation.

$ btrfs filesystem mkswapfile --size 64M nocow; echo "$?"
ERROR: cannot set NOCOW flag: Operation not supported
0
$ ls -l nocow
-rw------- 1 user user 0 Oct 19 23:13 nocow

Link: #1186