bcache: Convert btree_insert_check_key() to btree_insert_node()

This was the main point of all this refactoring - now,
btree_insert_check_key() won't fail just because the leaf node happened
to be full.

Signed-off-by: Kent Overstreet <kmo@daterainc.com>
diff --git a/drivers/md/bcache/btree.h b/drivers/md/bcache/btree.h
index 6d2fb75..73bd621 100644
--- a/drivers/md/bcache/btree.h
+++ b/drivers/md/bcache/btree.h
@@ -216,6 +216,8 @@
 	return __bch_btree_iter_init(b, iter, search, b->sets);
 }
 
+void __bkey_put(struct cache_set *c, struct bkey *k);
+
 /* Looping macros */
 
 #define for_each_cached_btree(b, c, iter)				\
@@ -380,8 +382,8 @@
 struct btree *bch_btree_node_get(struct cache_set *, struct bkey *,
 				int, struct btree_op *);
 
-bool bch_btree_insert_check_key(struct btree *, struct btree_op *,
-				   struct bio *);
+int bch_btree_insert_check_key(struct btree *, struct btree_op *,
+			       struct bkey *);
 int bch_btree_insert(struct btree_op *, struct cache_set *);
 
 int bch_btree_search_recurse(struct btree *, struct btree_op *);