Vibe-Coded Ext4 for OpenBSD

Summary

By Jonathan CorbetMarch 26, 2026 A number of projects have been struggling with the question of which submissions created by large language models (LLMs), if any, should be accepted into their code base. This discussion has been further muddied by efforts to use LLM-driven reimplemention as a way to remove copyleft restrictions from a body of existing code, as recently happened with the Python chardet module. In this context, an attempt to introduce an LLM-generated implementation of the Linux ext4 filesystem into OpenBSD was always going to create some fireworks, but that project has its own, clearly defined reasons for looking askance at such submissions. It all started on March 17, when Thomas de Grivel posted an ext4 implementation to the openbsd-tech mailing list. This implementation, he said, provides full read and write access and passes the e2fsck filesystem checker; it does not support journaling, however. The code includes a number of copyright assertions, but says nothing about how it was written. In a blog post, though, de Grivel was more forthcoming about the code's provenance: No Linux source files were ever read to build this driver. It's pure AI (ChatGPT and Claude-code) and careful code reviews and error checking and building kernel and rebooting/testing from my part. There were a number of predictable concerns raised about this code, many having to do with the possibility that it could be considered to be a derived product of the (GPL-licensed) Linux implementation. The fact that the LLM in question was almost certainly trained on the Linux ext4 code and documentation does not help. Bringing GPL-licensed code into OpenBSD is, to put it lightly, not appreciated; Christian Schulte was concerned about license contamination: I searched for documentation about that ext4 filesystem in question. I found some GPL licensed wiki pages. The majority of available documentation either directly or indirectly points at GPL licensed code. In my understanding of th...