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Subject: Re: WARN_ON in record_root_in_trans() when deleting freshly renamed
 subvolume
To: Filipe David Manana <fdmanana@gmail.com>
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Cc: linux-btrfs <linux-btrfs@vger.kernel.org>, Mark Fasheh <mfasheh@suse.de>,
        Qu Wenruo <quwenruo@cn.fujitsu.com>
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Date: Fri, 8 Apr 2016 15:10:35 +0200
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[cc: Mark and Qu]

On 04/08/16 13:51, Holger Hoffstätte wrote:
> On 04/08/16 13:14, Filipe Manana wrote:
>> Using Chris' for-linus-4.6 branch, which is 4.5-rc6 + all 4.6 btrfs
>> patches, it didn't reproduce here:
> 
> Great, that's good to know (sort of :). Thanks also to Liu Bo.
> 
>> Are you sure that you are not using some patches not in 4.6?

We have a bingo!

Reverting "qgroup: Fix qgroup accounting when creating snapshot"
from last Wednesday immediately fixes the problem.

Was quite easy to find - the triggered WARN_ON was the second one that
complained about a mismatch between roots. The only patch that even
remotely did something in that area was said qgroup fix.

Looks like something is missing there. Suggestions welcome. :)

Holger