On Wed, Apr 27, 2016 at 09:59:38AM -0400, Chris Mason wrote:
> > @@ -2854,9 +2855,16 @@ static void delayed_ref_async_start(struct btrfs_work *work)
> >
> > async = container_of(work, struct async_delayed_refs, work);
> >
> > - trans = btrfs_join_transaction(async->root);
> > + trans = btrfs_attach_transaction(async->root);
> > if (IS_ERR(trans)) {
> > - async->error = PTR_ERR(trans);
> > + if (PTR_ERR(trans) != -ENOENT)
> > + async->error = PTR_ERR(trans);
> > + goto done;
> > + }
>
> This ends up deadlocking because btrfs_attach_transaction waits in ways
> that join does not. The differences between these two are really
> subtle, and we manage to make this mistake every year or so.
>
> Subject: [PATCH] btrfs: fix deadlock in delayed_ref_async_start
>
> "Btrfs: track transid for delayed ref flushing" was deadlocking on
> btrfs_attach_transaction because its not safe to call from the async
> delayed ref start code. This commit brings back btrfs_join_transaction
> instead and checks for a blocked commit.
>
> Signed-off-by: Josef Bacik <jbacik@xxxxxx>
> Signed-off-by: Chris Mason <clm@xxxxxx>
This patch seems to be an incremental but I don't see the original patch
from Josef merged anywhere (I haven't picked it to for-next yet), are
you going to commit both?
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