[$] Toward fast, containerized, user-space filesystems

Filesystems are complex and performance-sensitive beasts. They can alsopresent security concerns. Microkernel-based systems have long pushedfilesystems into separate processes in order to contain any vulnerabilitiesthat may be found there. Linux can do the same with the Filesystem inUserspace (FUSE) subsystem, but using FUSE brings a significantperformance penalty. Darrick Wong is working on ways to eliminate thatpenalty, and he has a massive patchset showing how ext4 filesystems can be safely implemented in user space byunprivileged processes with good performance. This work has the potentialto radically change how filesystems are managed on Linux systems.