The Bcachefs file system recently hit a major milestone, but not the one developers hoped for. Linus Torvalds officially removed the core Bcachefs code from the main Linux kernel tree. This definitive action follows months of internal tension and shifting development strategies.
Torvalds justified the removal because the in-kernel Bcachefs code is stale. The Bcachefs project already transitioned to an external distribution model. Therefore, keeping the outdated code inside the kernel would only cause version confusion.
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Bcachefs is Externally Maintained Since Kernel 6.17
Earlier this year, Linus Torvalds publicly indicated that he and Bcachefs maintainer Kent Overstreet would be "parting ways in the 6.17 merge window". Linus felt uncomfortable staying involved because disagreements arose about the protocol for submitting bug fixes.
Consequently, the Bcachefs maintenance status quickly changed. On 2025-08-28, the MAINTAINERS file changed Bcachefs's status from "Supported" to "Externally maintained".
This change meant the version of the code remaining in the mainline kernel stopped receiving updates. Furthermore, maintainers would not backport downstream patches.
Bcachefs Moves to DKMS Modules
This disengagement by the mainline kernel forced Bcachefs development to pivot its distribution method.
As a result, Bcachefs is now switching to distribution as a DKMS module. This transition started with Linux 6.17 and bcachefs-tools 1.31.5.
A normal install process for bcachefs-tools now installs the necessary kernel module sources. A properly functioning DKMS package then builds these modules, making them available just like any other kernel module.
The external DKMS version supports Linux 6.16 and newer kernels. The Bcachefs developers plan development to continue tracking prereleases of the main kernel. This ensures support is ready before each major kernel release.
What Users Should Know About Migration
Most users running Bcachefs must now plan for migration. Fortunately, the migration process should prove "fairly seamless" for most individuals.
Bcachefs maintainers confirm that users can still use Bcachefs as their root filesystem. Users just need an initramfs to load the external DKMS module.
Bcachefs maintainer Kent Overstreet has assured users that development standards remain high. He expects no change in QA or stability of releases going forward. The focus continues on fixing remaining bugs to eventually lift the experimental label.
Bcachefs APT Repository
Bcachefs developers realized that the existing bcachefs-tools package in Debian was orphaned and eventually removed.
So the they have setup a dedicated APT repository for Debian and Ubuntu users.
You can find this new resource index at apt.bcachefs.org. This repository includes packages targeted at current and future Debian/Ubuntu releases, specifically naming unstable, trixie, questing, plucky, and forky.
To learn how to install bcachefs via the APT repository on Debian-based systems, please visit the following link:
Distribution Support Status
Distributions have started adapting their packaging processes:
- Arch and NixOS offer "first tier support". Users of these distributions typically do not need to do anything for the DKMS migration, because the
bcachefs-toolspackages already updated. - Fedora users can find the
bcachefs-toolspackage via a COPR, as Fedora policy prevents shipping out-of-tree kernel modules in the main distribution. - OpenSUSE decided to delay the disabling of Bcachefs until kernel 6.18. OpenSUSE made this decision to provide users enough time to transition. The distribution warns users that the older in-kernel version may miss critical fixes due to its "externally maintained" status.
For people who prefer not dealing with DKMS, Kent Overstreet’s kernel repository remains available for source compilation.
