Flood uses df -T in server/util/diskUsageUtil.ts where it defines the disks in use. However, I have a box that has a jail and df is useless as it shows all other filesystems we don't use in our jail. Users have to use quota to get their own data usage on their space.
As quota uses different format than df it's not enough to just change the command. We also need more arguments to get all data in the same line:
$ quota -w --show-mntpoint
Disk quotas for user rolle (uid 1020):
Filesystem blocks quota limit grace files quota limit grace
/dev/sdb1 /home2 1059357988 3905945600 3905945600 266012 0 0