ReiserFS, Once Enterprise's Default, Removed in Linux 6.13

Once the default filesystem for SUSE Enterprise, ReiserFS-3 has now been removed from Linux 6.13. It was the first Linux filesystem to introduce journaling, alongside several modern features that were ahead of its time. There were ambitious plans for ReiserFS-4 and even ReiserFS-5, with bold claims of being the fastest filesystem of its era.

So, what happened? What led to Linux finally deciding to remove it in the 6.13 release?

Well, it sure wasn’t a knee-jerk decision. The kernel community discussed deprecating ReiserFS back in 2022, and it was officially marked as deprecated then. Removing it in Linux’s first 2025 release felt like a natural progression, leading to its removal in 6.13-rc1.

But that still doesn’t answer the real question: why was it marked as deprecated in the first place?

Linux is evolving at an incredible pace, with widespread adoption across everything from the tiniest embedded devices to supercomputers and hyperscalers powering the world’s largest data centers. This rapid growth brings a constant influx of new features, making it challenging for developers to deal with unmaintained subsystems that can’t keep up with the development pace.

ReiserFS fell into this category, remaining unmaintained after its lead developer, Hans Reiser, was convicted of murdering his wife. Recently, Hans wrote a letter to the kernel community, leaving it up to them to decide what’s best and to take action accordingly.

For those interested, the design of ReiserFS-4 is still maintained and available online at internet archive. Hans Reiser’s letter to the kernel community, along with images of the original handwritten note, can be found on the LKML archives.

What does this mean for users still using ReiserFS?

Most users have likely already migrated their data to other filesystems. However, for those who haven’t, the best advice would be, to stick to 6.12 kernel and start planning a migration to a filesystem supported by Linux 6.13.