I upgraded to sys-fs/device-mapper-1.02.22 from 1.02.19-r1. When I now run df, I get something like this: askwar@hetzner ~ $ df Filesystem 1K-blocks Used Available Use% Mounted on /dev/hda5 484602 315987 163611 66% / udev 10240 136 10104 2% /dev devshm 253956 0 253956 0% /dev/shm /dev/dm-1 2844672 1794948 1049724 64% /usr /dev/dm-4 1048540 195464 853076 19% /tmp Note the "/dev/dm-1" and "dm-4". This used to look something like this: --($:~)-- df Dateisystem 1K-Blöcke Benutzt Verfügbar Ben% Eingehängt auf /dev/sda6 489992 287403 177289 62% / udev 10240 168 10072 2% /dev /dev/mapper/sys-Gentoo 4521840 2950912 1570928 66% /Gentoo /dev/mapper/sys-Home 3192584 2748392 444192 87% /home The new output (with /dev/dm-*) is pretty much useless, as it hides the information on what volumegroup and logical volume the filesystem is located. "I" suppose it's because of a change in 64-device-mapper.rules? As it is now, the files in /dev/mapper are now symlinks to /dev/dm-*. It used to be so, that the files in /dev/mapper where the real block device files.
*** This bug has been marked as a duplicate of bug 190819 ***