Re: btrfs: still lockdep splat for 4.9-rc5+ (btrfs_log_inode)

[Liu Bo]

On Sat, Nov 26, 2016 at 08:46:38AM -0500, Chris Mason wrote:
> On Fri, Nov 25, 2016 at 10:03:25AM +0100, Christian Borntraeger wrote:
> > FWIW, I still see the lockdep splat in btrfs in 4.9-rc5+
> 
> Filipe reworked the code to avoid taking the same lock twice.  As far as I
> can tell, this just needs some annotation.

Besides this log_mutex, we have another false lockdep warning around
block_group_cache->data_rwsem, we can use down_read_nested() to get rid
of it.

Thanks,

-liubo