Re: [PATCH 1/2] Btrfs: rescan for qgroups

[Jan Schmidt <list.btrfs@jan-o-sch.net>]

On Mon, April 15, 2013 at 08:08 (+0200), Wang Shilong wrote:
> Hello Jan,
> 
>> On Mon, April 15, 2013 at 07:44 (+0200), Jan Schmidt wrote:
>>> Thanks, v2 to come.
>>
>> Uh, but not immediately. I didn't get tracking of "exclusive" right. That will
>> need some time to fix and test.
> 
> 
> 'exclusive' adds the complexity of btrfs qgroup.
> So if you send V2. I'd like you add more lines in changelog.

Yes, the commit message will be longer as you requested previously. This does
not include a complete description on how "exclusive" works. The qgroup pdf
explains that.

> Besides, i have a question in my mind.(I have not seen you code)..
> When qgroup rescan  will happen?
> 
> 1> when quota is enabled

That's what the second patch does, yes. Your patches should be merged in a way
that we first create the level 0 qgroups for all subvolumes and then start the
rescan, obviously.

> 2> if a new qgroup relations is created, rescan should happen?

With your patches, there will be no subvolume qgroups missing. For the higher
level groups, one needs expert knowledge anyway. I think it's best to leave that
decision to the administrator configuring those qgroups.

> 2> user call qgroup rescan..

Of course, yes.

-Jan