How do I see how much space is used in the overlay file (Fedora USB)?

[liveuser@localhost ~]$ df -h
Filesystem            Size  Used Avail Use% Mounted on
/dev/mapper/live-rw   3.0G  2.2G  771M  75% /
tmpfs                1013M  288K 1013M   1% /dev/shm
/dev/sdb1              15G  8.3G  6.8G  55% /mnt/live
varcacheyum          1013M     0 1013M   0% /var/cache/yum
/tmp                 1013M  104K 1013M   1% /tmp
vartmp               1013M     0 1013M   0% /var/tmp

The above command output does not seem to reflect the 2GB overlay.

Is there a way to output "just" the overlay contents? Something like 'du -hs' (du shows what /dev/mapper shows).
 

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Kam Salisbury
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