I can't find a patch for reiser4 for kernels newer than 2.6.38.
- How to access reiser4 on modern kernels? The only workaround I know is to use a thing like mountlo (filesystem running in UML kernel with reiser4, with FUSE interface).
- Are there well-supported filesystems like reiser4 (transparent compression, fast, good support for small files). With reiser4 I can store 2 VMs that is 10 GB uncompressed on 2 GB partition (plus 40% free space), I can use small individual file for each entry in some ad-hoc database (like parse big wikipedia XML dump, store each article in a separate file, then compress it again in other way). I heard somewhere that BTRFS supports compression, but metadata overhead is considerable and that it is slow, is it true?