> sudo xfs_quota -xc 'report -h' /home
User quota on /home (/dev/hdb1)
                         Blocks
User ID      Used    Soft   Hard Warn/Grace
---------- ---------------------------------
root         4.6G       0      0 00 [------]
testuser   103.4G       0      0 00 [------]
...

Running report as an ordinary user simply reports that users disk usage while running as root allows the disk usage of all users to be reported.

Performance