Re: [PATCH v2] Btrfs: fix deadlock when enabling quotas due to concurrent snapshot creation

[Nikolay Borisov]

On 19.11.18 г. 16:48 ч., Qu Wenruo wrote:
> There may be some qgroup reserved space related problem in such case,
> but I'm not 100% sure to foresee such problem.

But why is this a problem - we always queue quota rescan following QUOTA
enable, that should take care of proper accounting, no?

> 
> 
> The best way to do this is, commit trans first, and before any other one
> trying to start transaction, we set the bit.
> However I can't find such infrastructure now (I still remember we used
> to have a pending bit to change quota enabled flag, but removed later)