Are 'guix gc' stats exaggerated?

[Felix Lechner]

Hi,

Today I ran 'guix gc' on equipment with an ext4 root partition.  It had
these space characteristics beforehand:

    Filesystem  Size       Used      Avail     Use% Mounted on
    /dev/dm-3   309047680  157252980 138126064  54% /

or for human eyes:

    /dev/dm-3   295G        150G      132G      54% /

After the run, the drive showed:

    /dev/dm-3   309047680   88267956 207111088  30% /

or for human eyes:

    /dev/dm-3   295G         85G      198G      30% /

By my math, about 65.8 GiB were recovered.

When 'guix gc' was done, it announced:

    [184389 MiB] deleting '/gnu/store/...'
    deleting `/gnu/store/trash'
    deleting unused links...
    note: currently hard linking saves 59224.03 MiB
    guix gc: freed 110,649.49 MiBs

Seeing the 184389 MiB number, or 180 GiB, already made me suspicious.
It exceeded my drive usage by 30 GiB.  Even the more conservative 110649
MiB "freed," however, are off by a mile. That would have been 108 GiB,
or 42 GiB more than the space actually recovered.

Am I looking at those numbers the wrong way?  Thanks!

Kind regards
Felix