-* readahead:
- - drop /.readahead on bigger upgrades with yum
- - move readahead files into /var (look for them with .path units?)
- - readahead: use BTRFS_IOC_DEFRAG_RANGE instead of BTRFS_IOC_DEFRAG ioctl, with START_IO
- - readahead: when bumping /sys readahead variable save mtime and compare later to detect changes
- - readahead: make use of EXT4_IOC_MOVE_EXT, as used by http://e4rat.sourceforge.net/
-