Besides no discussion for years of possibly bringing Reiser4 upstream, nor any attempt to bring Reiser5 online, it seems that the original, feature-rich ReiserFS filesystem for its original era could be coming out of the Linux kernel in 2022.
ReiserFS was introduced 21 years ago as the first Linux kernel journaling file system to be integrated and offered innovative features for its time among the first open source file systems. For a time, ReiserFS was used by default on SUSE Linux and during the Namesys era it continued to see active feature development. But since the lead developer of ReiserFS, Hans Reiser, was found guilty of murdering his wife a decade and a half ago, there hasn’t been much work on ReiserFS (or Reiser4) other than from former Namesys developer Edward Shishkin. While Shishkin has moved forward with Reiser4/Reiser5 out of the tree, ReiserFS has been left to code rot with diminished user interest and no company seems willing to get involved given its connection to Hans Reiser . Also these days EXT4, XFS and Btrfs are all better choices and even OpenZFS.
It’s been a long time since ReiserFS has been relevant to the Linux masses.
Started in a discussion this week by long-time kernel developer Matthew Wilcox, there is a discussion about the removal of ReiserFS. Wilcox’s motivation to remove ReiserFS is due to the kernel infrastructure changes it is pursuing, but ReiserFS being the only remaining user of a particular flag blocking its work. Additionally, he notes that ReiserFS has barely seen new work in recent years besides Syzbot fixes and other tree-wide code changes. There doesn’t seem to be any user-spotted bug fixes since at least 2019.
Following this thread, Edward Shishkin posted a fix for ReiserFS to get rid of the AOP_FLAG_CONT_EXPAND flag, which prompted Wilcox to start the discussion in the first place. However, other kernel developers have intervened with interest to deprecate/remove the filesystem. It’s possible that ReiserFS was deprecated for a few kernel versions before it was actually removed, which is common practice for kernel feature removal.
When was the last time you used the ReiserFS file system? (It could be deleted from the main line #Linux core.)
— Phoronix (@phoronix) February 22, 2022
Judging from the comments so far, it looks like ReiserFS may be deprecated in 2022 for possible removal in a future major Linux kernel release. Dave Chinner also suggested possibly considering a deprecation with plans to remove other older Linux filesystems that are unmaintained and not 2038 compliant.