bcache: Avoid deadlocking in garbage collection

Not a complete fix - we could still deadlock if btree_insert_node() has
to split...

Signed-off-by: Kent Overstreet <kmo@daterainc.com>
diff --git a/drivers/md/bcache/btree.h b/drivers/md/bcache/btree.h
index b5a46af..767e755 100644
--- a/drivers/md/bcache/btree.h
+++ b/drivers/md/bcache/btree.h
@@ -271,7 +271,7 @@
 void bch_btree_node_write(struct btree *, struct closure *);
 
 void bch_btree_set_root(struct btree *);
-struct btree *bch_btree_node_alloc(struct cache_set *, int);
+struct btree *bch_btree_node_alloc(struct cache_set *, int, bool);
 struct btree *bch_btree_node_get(struct cache_set *, struct bkey *, int, bool);
 
 int bch_btree_insert_check_key(struct btree *, struct btree_op *,