Re: [PATCH v4 0/4] btrf_show_devname related fixes

[Anand Jain <anand.jain@oracle.com>]

On 31/08/2021 23:40, David Sterba wrote:
> On Wed, Aug 25, 2021 at 10:13:52AM +0800, Anand Jain wrote:
>> On 25/08/2021 00:11, David Sterba wrote:
>>> On Tue, Aug 24, 2021 at 08:28:09AM +0800, Anand Jain wrote:
>>>>
>>>>
>>>> On 24/08/2021 03:46, David Sterba wrote:
>>>>> On Mon, Aug 23, 2021 at 07:31:38PM +0800, Anand Jain wrote:
>>>>>> These fixes are inspired by the bug report and its discussions in the
>>>>>> mailing list subject
>>>>>>     btrfs: traverse seed devices if fs_devices::devices is empty in show_devname
>>>>>>
>>>>>> And depends on the patch
>>>>>>     [PATCH v2] btrfs: fix lockdep warning while mounting sprout fs
>>>>>> in the ML
>>>>>>
>>>>>> v4:
>>>>>>     Fix unrelated changes in 2/4
>>>>>> v3:
>>>>>>     Fix rcu_lock in the patch 3/4
>>>>>>
>>>>>> Anand Jain (4):
>>>>>>      btrfs: consolidate device_list_mutex in prepare_sprout to its parent
>>>>>>      btrfs: save latest btrfs_device instead of its block_device in
>>>>>>        fs_devices
>>>>>>      btrfs: use latest_dev in btrfs_show_devname
>>>>>>      btrfs: update latest_dev when we sprout
>>>>>
>>>>> Patchset survived one round of fstests and I haven't seen the lockdep
>>>>> warning in btrfs/020 that's caused by some unrelated work in loop device
>>>>> driver.
>>>>
>>>>
>>>>> There's a series from Josef to fix it by shuffling locking,
>>>>
>>>>     Hm. Is it a recent patch? I can't find.
>>>
>>> https://lore.kernel.org/linux-btrfs/cover.1627419595.git.josef@toxicpanda.com/
>>
>> Thx.
>> It is the same fix I sent ~3months before in the ML[1].
> 
> Well, I've seen the patch and pings but sometimes the timing is not good
> and there's something else I have to finish before looking into new
> area. And device locking is something that needs full attention. The
> bugs/warnings in question weren't that important.

  Ah. Thanks for taking the time to explain.

> But anyway now the 5.15 branch is out and there are several patches
> regarding the devices so I'm going to spend time on that.

  Thx. That includes read_policy patchset as well? Let me know so that I
  can refresh/resend.

>  Also because
> the recent updates to loop devices started to trigger lockdep warnings
> that make testing harder and we're missing lockdep in many tests.

  I am reviewing the patch 1 and 2 in Josef list.