vfs fix from I74f5217ba3c4be73e91f33f900f1f0c26810cc05 merge
ext4 fixes
sysfs memory leak fix
experimental page-writeback delayed until screen is off (accordingly to https://github.com/Firtecy/kowalski/commit/5c194eaf20bff3868bfe42f36a7b9e67c30518b9)