SUMMARY I have an encrypted btrfs volume on an external USB SSD. While it is unmounted it shows 55.02GB used. When it is mounted, it shows 5.02GB used. The partition is empty and 5.02GB is likely just journal information for the filesystem I guess. STEPS TO REPRODUCE I'm not even sure how this happens, it just exists on my drive. OBSERVED RESULT Used space differs between mounted and unmounted state of partition. EXPECTED RESULT Used space is the same whether the partition is mounted or unmounted. Operating System: Solus 4.7 KDE Plasma Version: 6.2.5 KDE Frameworks Version: 6.11.0 Qt Version: 6.8.2 Kernel Version: 6.12.12-313.current (64-bit) Graphics Platform: Wayland Processors: 16 × AMD Ryzen 7 PRO 4750U with Radeon Graphics Memory: 29.1 GiB of RAM Graphics Processor: AMD Radeon Graphics Manufacturer: LENOVO Product Name: 20Y1001SAU System Version: ThinkPad P14s Gen 1
Hmm, it uses different sources of data. I don't know which one would be correct in your case. When partition is mounted QStorageInfo from Qt is used (https://doc.qt.io/qt-6/qstorageinfo.html) which under the hood calls statfs64 syscall and asks kernel how much space is used. When partition is unmounted we call btrfs filesystem show --raw and parse that. Presumably the first source is more accurate since it comes from the kernel...
The 5.02GB one when mounted would be correct. There was no content in the drive.
(In reply to Justin Zobel from comment #2) > The 5.02GB one when mounted would be correct. There was no content in the > drive. Well, that's what we are using when that info is available. But then partition is unmounted, we can't use that. So does sudo btrfs filesystem show --raw show wrong info for you if you run it manually?
Unfortunately, that volume is now gone. On my current system I see in Partition Manager: 125GiB of 472.94GiB Via BTRFS: sudo btrfs filesystem show --raw Label: 'KDELinux' uuid: 50a6d7b1-c8ee-4aeb-b1ce-3b8376e836be Total devices 1 FS bytes used 126785499136 devid 1 size 507794214912 used 134242893824 path /dev/mapper/root And those numbers seem to match up, but that partition is mounted.
Anyway, not much we can do in partitionmanager itself here (especially if the btrfs tool was inaccurate). We use better source (kernel info) when it is available...