Re: [report] lockdep warning when mounting seed device

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

On 26/02/2021 23:10, David Sterba wrote:
> On Fri, Feb 26, 2021 at 01:01:02PM +0800, Anand Jain wrote:
>> On 25/02/2021 12:39, Su Yue wrote:
>>>
>>> While playing with seed device(misc/next and v5.11), lockdep complains
>>> the following:
>>>
>>> To reproduce:
>>>
>>> dev1=/dev/sdb1
>>> dev2=/dev/sdb2
>>>
>>> umount /mnt
>>>
>>> mkfs.btrfs -f $dev1
>>>
>>> btrfstune -S 1 $dev1
>>>
>>> mount $dev1 /mnt
>>>
>>> btrfs device add $dev2 /mnt/ -f
>>>
>>> umount /mnt
>>>
>>> mount $dev2 /mnt
>>>
>>> umount /mnt
>>>
>>>
>>
>> In my understanding the commit 01d01caf19ff7c537527d352d169c4368375c0a1
>>    (btrfs: move the chunk_mutex in btrfs_read_chunk_tree
>>    fixed this bug in 5.9.
>> Could you please try this [1] patch,
>> [1]
>> https://patchwork.kernel.org/project/linux-btrfs/patch/20200717100525.320697-1-anand.jain@oracle.com/
>> Patch [1] still relevant as the device_list_mutex in clone_fs_devices()
>> is redundant. We could remove it as well.
> 
> So the fix 01d01caf19ff7c was not sufficient, the lockdep splat is
> reproducible.

Yes indeed. Except for adding another reported by, the patch[1] applies
on misc-next as it is. Do you need a resend of the patch?

Thanks, Anand