SUSE takes snapshots before packages are installed. The package manager cannot tell if the disk will fill up as a result because on Btrfs the `df` command lies.

If its Btrfs root fills up and the OS writes to it, it 100% will self-destruct, and the `btrfs-repair` tool (`fsck` replacement) cannot fix drives and usually makes the corruption worse and renders the drive unreadable.

This is why in the earlier thread about swapfiles...

https://news.ycombinator.com/item?id=49618087

... I advised 2 commenters not to recommend keeping the OS and data in a single big volume. I got downvoted for it. I was rude. Well, I was, but I stand by my comments even though I'm sorry for my tone when I made them.

A pragmatic fix would trigger read-only failure mode at 90% usage of the mount as a whole, with all subvolumes.

And you know what, that's a great idea.