Re: [PATCH 0/3] fixup work fixes

[David Sterba <dsterba@suse.cz>]

On Tue, Jan 21, 2020 at 11:51:41AM -0500, Josef Bacik wrote:
> This series is to address a few issues with the fixup worker we hit in
> production.
> 
> The first of this is a resend of
> 
>   Btrfs: keep pages dirty when using
> 
> I've cleaned this up based on the feedback and added a bunch more comments to
> make it clear what is happening and why we're doing it.
> 
> The next patch is a cleanup that is made possible by the previous patch, again
> to clear up the fixup workers job.
> 
>   btrfs: drop the -EBUSY case in __extent_writepage_io
> 
> And finally the deadlock fix that I submitted earlier.  I noticed while trying
> to backport this onto our kernel that we had changed the error case with the
> above patch from Chris, and actually we really, really need Chris's fix as well.
> There is also a change in the error handling from v1 where we now set the page
> error properly but only once we've locked the page and verified we're still
> responsible for COW'ing the page.  Thanks,

Reviewed-by: David Sterba <dsterba@suse.com>

Very tricky stuff that fixup worker, it's like the worst present a
filesystem can get from memory management.

Estimated Merge target is 5.6, post rc1 so we have enough time for
testing. It'll appear either in misc-next or for-next.