Comment # 4 on bug 933428 from Mark Fasheh

(In reply to Mark Fasheh from comment #3)
> (In reply to David Sterba from comment #2)
> > This is caused by
> > https://www.mail-archive.com/linux-btrfs@vger.kernel.org/msg41982.html and
> > needs a patch to kernel as well, I'll look up which one.
> > 
> > On an unpatched kernel the warning will show up even after the quotas are
> > rescanned and should be mostly harmless.
> 
> Did you ever find which patch we want for the kernel? Btw, I can confirm
> that this is cosmetic but obviously wants fixing.

By 'which patch' I mean whether you found the source as this happens upstream.
If not, I'll take a look.