Next Bcachefs Release Aims To Include Rust Code In The Kernel Module
Next Bcachefs Release Aims To Include Rust Code In The Kernel Module
https://www.phoronix.com/news/Bcachefs-1.38.7-Rust-Kernel
Publish Date: 2026-06-29 15:30:00
Source Domain: www.phoronix.com
The Bcachefs file-system already makes use of the Rust programming language in the user-space tools for this CoW file-system and they have been planning to make use of Rust within the kernel module too. Beginning in the next Bcachefs release, v1.38.7, they are looking at beginning to include Rust code now in their kernel driver.
Bcachefs 1.38.6 debuted just days ago with some nice improvements while already its lead developer, Kent Overstreet, is eyeing big changes for Bcachefs 1.38.7. In a post today he outlined plans for Bcachefs 1.38.7 to be the first release where they begin including Rust in the in-kernel Bcachefs module. Initially it will be a soft dependency while they get their deployment processes handled and related infrastructure laid.
This plan to use Rust within the Bcachefs kernel module does complicate the handling with Bcachefs being out-of-tree. Kent Overstreet noted the challenges in using the Dynamic Kernel Module System (DKMS) builds around Rust. DKMS builds of Rust modules are “not going to be practical” for most users due to the installed version of Rustc needing to match the version used to compile the kernel, given Rust’s lack of a stable ABI.
Furthermore, the same Rust stdlib sources need to be installed, the bindgen CLI version also needs to be installed, and some Rust artifacts from the kernel build must also be present. Thus Bcachefs is ultimately planning to target more normal distribution binary packages for kernel modules rather than DKMS builds moving ahead. This will be a similar challenge to any other project with out-of-tree Rust kernel modules.
More details on the Rust code in Bcachefs kernel module plans can be found via today’s Patreon post.
