How to find/reclaim missing space in volume

[Marc MERLIN <marc@merlins.org>]

I have this:
sauron [mc]# df -h .
Filesystem         Size  Used Avail Use% Mounted on
/dev/mapper/pool2  1.1T  853G  212G  81% /mnt/btrfs_pool2
sauron [mc]# btrfs fi show .
Label: 'btrfs_pool2'  uuid: fde3da31-67e9-4f88-b90d-6c3f6becd56a
	Total devices 1 FS bytes used 847.89GiB
	devid    1 size 1.04TiB used 890.02GiB path /dev/mapper/pool2
sauron [mc]# btrfs fi df .
Data, single: total=878.00GiB, used=843.85GiB
System, DUP: total=8.00MiB, used=128.00KiB
Metadata, DUP: total=6.00GiB, used=4.04GiB
GlobalReserve, single: total=512.00MiB, used=0.00B


sauron:/mnt/btrfs_pool2# du -sh *
599G	varchange2
598G	varchange2_ggm_daily_ro.20230605_07:57:43
4.0K	varchange2_last
599G	varchange2_ro.20230605_08:01:30
599G	varchange2_ro.20230605_09:01:43

I'm confused, the volumes above are snapshots with mostly the same data
(made within the last 2 hours) and I didn't delete any data in the FS
(they are mostly identical and used for btfrs send/receive)

Why do they add up ot 600GB, but btrfs says 847FB is used?

Thanks,
Marc
-- 
"A mouse is a device used to point at the xterm you want to type in" - A.S.R.
 
Home page: http://marc.merlins.org/                       | PGP 7F55D5F27AAF9D08