Re: [PATCH v2 2/2] btrfs: automatically remove the subvolume qgroup

[David Sterba <dsterba@suse.cz>]

On Fri, Apr 26, 2024 at 07:21:08AM +0930, Qu Wenruo wrote:
> > btrfs subvolume delete 123
> > btrfs subvolume sync 123
> > btrfs qgroup remove 0/123
> >
> > but this needs to wait until the sync is finished and that is not
> > expected for the subvolume delete command.
> 
> That's the problem, and why doing it in user space has it limits.
> 
> Furthermore, with drop_subtree_threshold or other qgroup operations
> marking the qgroup inconsistent, you can not delete that qgroup at all,
> until the next rescan.

Ok so that makes it more complicated and better solved in kernel, with
the compatibility issues mentioned in the other mail.

> > It needs to be fixed but now
> > I'm not sure this can be default in 6.9 as planned.
> 
> I'd say, you should not implement this feature without really
> understanding the challenges in the first place.
> 
> And that's why I really prefer you send out non-trivial btrfs-progs for
> review, other than pushing them directly into github repo.

As discussed on slack, the development happens in git, for btrfs-progs
the mails are overhead that does not pay off.