Created attachment 127490 [details]
The plasmoids settings with zfs datasets missing

I hope this is the right place to report this, if not please move it to the right place.


The "Hard Disk Space Usage" plasmoid is not able to show the size and usage of ZFS datasets. 
I run ZFS on root and the plasmoid is nearly useless in this configuration.


STEPS TO REPRODUCE
1. Install ZFS
2. Create a pool and some datasets
3. Add the plasmoid 
4. Open its settings


OBSERVED RESULT
There are no ZFS datasets selectable.

EXPECTED RESULT
Make datasets visible

SOFTWARE/OS VERSIONS

Linux/KDE Plasma: I'm running Kubuntu 20.04 at the moment, but I was running 18.04, 18.10, 19.04 and 19.10 before and the behaviour was in all of them.

ADDITIONAL INFORMATION
If zfs list is issued on the command line a list of all datasets including their names (with pool) is returned. df -h is not working properly with zfs. The command zfs list also offers how much space is used for the datasets and how much space is free in the respective pool. For datasets, which contain other datasets the total usage amount of all datasets underneath is summed up.
e.g.:
ry86@tuxedo:/home/ry86  $ zfs list
NAME                                               USED  AVAIL     REFER  MOUNTPOINT
bpool                                              333M  1,42G       96K  /boot
bpool/BOOT                                         331M  1,42G       96K  none
bpool/BOOT/ubuntu_eibl7w                           331M  1,42G     98,3M  /boot
rpool                                              201G   256G       96K  /
rpool/ROOT                                        11,3G   256G       96K  none
rpool/ROOT/ubuntu_eibl7w                          11,3G   256G     5,86G  /
rpool/ROOT/ubuntu_eibl7w/srv                       152K   256G       96K  /srv
rpool/ROOT/ubuntu_eibl7w/usr                       576K   256G       96K  /usr
rpool/ROOT/ubuntu_eibl7w/usr/local                 480K   256G      152K  /usr/local
rpool/ROOT/ubuntu_eibl7w/var                      3,15G   256G       96K  /var
rpool/ROOT/ubuntu_eibl7w/var/games                  96K   256G       96K  /var/games
rpool/ROOT/ubuntu_eibl7w/var/lib                  1,85G   256G     1,08G  /var/lib
rpool/ROOT/ubuntu_eibl7w/var/lib/AccountServices    96K   256G       96K  /var/lib/AccountServices
rpool/ROOT/ubuntu_eibl7w/var/lib/NetworkManager   1,88M   256G      160K  /var/lib/NetworkManager
rpool/ROOT/ubuntu_eibl7w/var/lib/apt               391M   256G     83,2M  /var/lib/apt
rpool/ROOT/ubuntu_eibl7w/var/lib/dpkg              106M   256G     51,6M  /var/lib/dpkg
rpool/ROOT/ubuntu_eibl7w/var/log                   143M   256G     49,2M  /var/log
rpool/ROOT/ubuntu_eibl7w/var/mail                   96K   256G       96K  /var/mail
rpool/ROOT/ubuntu_eibl7w/var/snap                 1,16G   256G      807M  /var/snap
rpool/ROOT/ubuntu_eibl7w/var/spool                 928K   256G      112K  /var/spool
rpool/ROOT/ubuntu_eibl7w/var/www                    96K   256G       96K  /var/www
rpool/USERDATA                                     190G   256G       96K  /
rpool/USERDATA/root_ezu56w                        1,08M   256G      344K  /root
rpool/USERDATA/ry86_ezu56w                         190G   256G      185G  /home/ry86