# btrfsck --readonly /dev/nvme2n1p6
Opening filesystem to check...
Checking filesystem on /dev/nvme2n1p6
UUID: 8d...
[1/7] checking root items
[2/7] checking extents
[3/7] checking free space tree
[4/7] checking fs roots
[5/7] checking only csums items (without verifying data)
[6/7] checking root refs
[7/7] checking quota groups skipped (not enabled on this FS)
found 241980678144 bytes used, no error found
total csum bytes: 229635788
total tree bytes: 3186114560
total fs tree bytes: 2615017472
total extent tree bytes: 247808000
btree space waste bytes: 621915705
file data blocks allocated: 465312006144
 referenced 300238901248

# mount /dev/nvme2n1p6 /mnt/pnt
# btrfs scrub start -Bd /mnt/pnt

Scrub device /dev/nvme2n1p6 (id 1) done
Scrub started:    Wed Jul 19 13:37:44 2023
Status:           finished
Duration:         0:04:22
Total to scrub:   225.36GiB
Rate:             880.80MiB/s
Error summary:    no errors found
# btrfs fi show /mnt/pnt
Label: 'btrfsRoot'  uuid: 8d...
	Total devices 1 FS bytes used 225.36GiB
	devid    1 size 281.07GiB used 261.49GiB path /dev/nvme2n1p6
# btrfs filesystem df /mnt/pnt
Data, single: total=255.46GiB, used=222.39GiB
System, single: total=32.00MiB, used=48.00KiB
Metadata, single: total=6.00GiB, used=2.97GiB
GlobalReserve, single: total=512.00MiB, used=0.00B