Re: [PATCH 4/4] btrfs: free anon_dev earlier to prevent exhausting anonymous block device pool

Josef Bacik
2020-06-16T23:31:14Z

On 6/16/20 6:48 PM, David Sterba wrote:
> On Tue, Jun 16, 2020 at 03:23:03PM -0400, Josef Bacik wrote:
>>> By freeing it earlier we reclaim the anon_dev quicker, hopefully to
>>> reduce the chance of exhausting the pool.
>>
>> Why isn't this happening as part of the root teardown once all the references to
>> it are gone? Thanks,
>
> This is where it happens now and is correct. The problem is that deleted
> subvolumes keep the id allocated until they are cleaned up, ie. all the
> dead roots consume the id though we don't need it anymore. Creating and
> deleting snapshots at large will produce a long list of dead subvolumes.
> THis patch will return the ids at the earlies possible moment so they
> can get reused.
>

Oh ok I misread, we're doing it earlier on purpose. Alright that's fine, you
can add

Reviewed-by: Josef Bacik <josef@toxicpanda.com>

Thanks,

Josef