Re: [Lsf-pc] [LSF/MM/BPF TOPIC] Removing GFP_NOFS

[Johannes Thumshirn <Johannes.Thumshirn@wdc.com>]

On 08.01.24 18:40, David Sterba wrote:
>> 199 - btrfs
> 
> All the easy conversions to scoped nofs allocaionts have been done, the
> rest requires to add saving the nofs state at the transactions tart, as
> said in above. I have a wip series for that, updated every few releases
> but it's intrusive and not finished for a testing run. The number of
> patches is over 100, doing each conversion separately, the other generic
> changes are straightforward.
> 
> It's possible to do it incrementally, there's one moster patch (300
> edited lines) to add a stub parameter to transaction start,
> https://lore.kernel.org/linux-btrfs/20211018173803.18353-1-dsterba@suse.com/ .
> There are some counter points in the discussion if it has to be done
> like that but IIRC it's not possible, I have examples why not.
> 

At a first glance, storing the nofs scope in the transaction handle like 
Filipe proposed sounds like a good idea to me.

Anyways, the deeper discussion on how we hope to solve it is nothing 
that needs to be done in this thread.