Re: Writeback bug causing writeback stalls

[Jan Kara]

 Hello Martinj!

On Wed 27-05-20 10:14:09, Martijn Coenen wrote:
> On Mon, May 25, 2020 at 9:31 AM Jan Kara <jack@xxxxxxx> wrote:
> > Well, most importantly filesystems like ext4, xfs, btrfs don't hold i_rwsem
> > when writing back inode and that's deliberate because of performance. We
> > don't want to block writes (or event reads in case of XFS) for the inode
> > during writeback.
> 
> Thanks for clarifying, that makes sense. By the way, do you have an
> ETA for your fix? We are under some time pressure to get this fixed in
> our downstream kernels, but I'd much rather take a fix from upstream
> from somebody who knows this code well. Alternatively, I can take a
> stab at the idea you proposed and send a patch to LKML for review this
> week.

I understand. I have written a fix (attached). Currently its under testing
together with other cleanups. If everything works fine, I plan to submit
the patches on Monday.

								Honza
-- 
Jan Kara <jack@xxxxxxxx>
SUSE Labs, CR