Filesystem in Userspace (FUSE) maintainer Miklos Szeredi led a birds-of-a-feather (BoF) discussion about the subsystem at the 2026 Linux Storage, Filesystem, Memory Management, and BPF Summit. In it, he talked about maintenance challenges, proposed features and their status, and his plans for a new FUSE API. There is a lot of interest and activity in the FUSE community these days it seems.

The Filesystem in Userspace (FUSE) subsystem provides a way to service filesystem requests from a user-space server, which moves the format-handling code out of the kernel. The FUSE server can use the io_uring facility for better performance, but Bernd Schubert is concerned that memory is being wasted because the current implementation has a single, large buffer size that is excessive for small I/O operations. He led a discussion on that topic in the filesystem track of the 2026 Linux Storage, Filesystem, Memory Management, and BPF Summit in Zagreb, Croatia.

The famfs filesystem, which is meant to provide shared access to huge memory-resident files on CXL and other devices, returned to the Linux Storage, Filesystem, Memory Management, and BPF Summit (LSFMM+BPF) in 2026. It was first discussed at LSFMM+BPF 2024 and a new implementation was described at the 2025 gathering, but it still has not made its way into the kernel; LWN looked at a discussion about merging famfs back in April 2026.

It should come as no surprise that a gathering of filesystem developers would discuss filesystem testing; it has been a mainstay of the Linux Storage, Filesystem, Memory Management, and BPF Summit over the years and the 2026 summit was no exception. Ted Ts'o led the discussion this time; he had a few different topics to raise, including his perception of increasing regressions for ext4 in the stable kernels and what can be done to help reduce them. As with other similar sessions at the summit over the years, there is a lot of interest in collaborating on test inputs and outputs, but finding a way to centralize that information has so far eluded the filesystem community.