btrfs quota examples?

[Tomasz Chmielewski <tch@virtall.com>]

I'm trying to use btrfs quotas, but I'm unable to find reliable
documentation on its usage.

Let's start with an empty subvolume:

- assign 200 MB space to it:

# btrfs qgroup limit 200m /mnt/btrfs-backup/tester/


- see the usage:

# btrfs qgroup show /mnt/btrfs-backup/tester/
0/803 0 0


- let's add a 100 MB file:

# dd if=/dev/urandom of=bigfile bs=1M count=100


- sync the FS to make sure quota is updated:

# btrfs filesystem
sync /mnt/btrfs-backup/ FSSync '/mnt/btrfs-backup/'


- see current quota usage:

# btrfs qgroup show /mnt/btrfs-backup/backuppc/tester/
0/803 104882176 104882176


Now, my questions:

- what do both 104882176 104882176 numbers represent?

- how can I verify the quota assigned to any given subvolume? I've assigned 200 MB, but how can I verify that number?


-- 
Tomasz Chmielewski
http://wpkg.org