Re: [PATCH 0/2] btrfs: fix a couple KCSAN warnings

[David Sterba <dsterba@suse.cz>]

On Wed, Feb 21, 2024 at 11:25:16AM +0000, Filipe Manana wrote:
> On Wed, Feb 21, 2024 at 11:13 AM David Sterba <dsterba@suse.cz> wrote:
> >
> > On Tue, Feb 20, 2024 at 12:24:32PM +0000, fdmanana@kernel.org wrote:
> > > From: Filipe Manana <fdmanana@suse.com>
> > >
> > > KCSAN reports a couple data races around access to block reserves.
> > > While they are very likely harmless it generates some noise and reports
> > > will keep coming, so address these.
> > >
> > > Filipe Manana (2):
> > >   btrfs: fix data races when accessing the reserved amount of block reserves
> > >   btrfs: fix data race at btrfs_use_block_rsv() when accessing block reserve
> >
> > Thre's another way to "fix" the KCSAN warnings, adding a data_race()
> > annotation to the access when it does not matter if the lock is taken or
> > not.
> >
> > In commit 748f553c3c4c "btrfs: add KCSAN annotations for unlocked access
> > to block_rsv->full" this was added for 'full', have you considered that
> > for 'reserved' too? The spin lock is also correct regarding the warning
> > but still increases the lock contention.
> 
> Yes, I have considered that, and in the change logs of the patches I
> mention why I chose to take the lock instead.

Ah sorry, I skimmed the changelogs too quickly, it's indeed there.

For both patches,

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