Re: [PATCH 2/3] Btrfs: rework qgroup accounting

[Josef Bacik <jbacik@fb.com>]

On 12/21/2013 03:56 AM, Wang Shilong wrote:
> Hello Josef,
>
> Though i know there are still problems related to qgroup(for example removing snapshot
> will beak qgroup accounting).I did a simple test about your patch..
>
>
> # btrfs quota enable /mnt
> # dd if=/dev/zero of=/mnt/data bs=4k count=102400 oflag=direct
> # btrfs sub snapshot /mnt/ /mnt/snap1
> # btrfs sub snapshot /mnt /mnt/snap2
> # btrfs sub delete /mnt/snap1 /mnt/snap2
> # sync
> # rm -rf /mnt/data
> # sync
> # dmesg
> # btrfs qgroup show /mnt
>
>
> Firstly, qgroup accounting is wrong, this is maybe expected because efficient  fs tree removal.
> However, from dmesg, i get the  WARNING:
>
> WARNING: CPU: 1 PID: 2650 at fs/btrfs/qgroup.c:1486 btrfs_delayed_qgroup_accounting
>
> I did not take a deep look at codes, but i think you will be interested in taking a look at this. ^_^

Yup we shouldn't be warning, but I didn't change anything wrt quotas and 
snapshot deletion, that's a whole other issue I don't care about right 
now ;).  Thanks,

Josef