bcachefs: bch2_btree_node_relock_notrace()

Most of the node_relock_fail trace events are generated from
bch2_btree_path_verify_level(), when debugcheck_iterators is enabled -
but we're not interested in these trace events, they don't indicate that
we're in a slowpath.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

fs/bcachefs/btree_iter.c

@@ -167,7 +167,7 @@ static void bch2_btree_path_verify_level(struct btree_trans *trans,
 	if (!btree_path_node(path, level))
 		return;
 
-	if (!bch2_btree_node_relock(trans, path, level))
+	if (!bch2_btree_node_relock_notrace(trans, path, level))
 		return;
 
 	BUG_ON(!btree_path_pos_in_node(path, l->b));

fs/bcachefs/btree_locking.c

@@ -401,7 +401,8 @@ static inline bool btree_path_get_locks(struct btree_trans *trans,
 }
 
 bool __bch2_btree_node_relock(struct btree_trans *trans,
-			      struct btree_path *path, unsigned level)
+			      struct btree_path *path, unsigned level,
+			      bool trace)
 {
 	struct btree *b = btree_path_node(path, level);
 	int want = __btree_lock_want(path, level);
@@ -416,6 +417,7 @@ bool __bch2_btree_node_relock(struct btree_trans *trans,
 		return true;
 	}
 fail:
+	if (trace)
 		trace_and_count(trans->c, btree_path_relock_fail, trans, _RET_IP_, path, level);
 	return false;
 }

fs/bcachefs/btree_locking.h

@@ -317,7 +317,7 @@ static inline int bch2_btree_path_relock(struct btree_trans *trans,
 		: __bch2_btree_path_relock(trans, path, trace_ip);
 }
 
-bool __bch2_btree_node_relock(struct btree_trans *, struct btree_path *, unsigned);
+bool __bch2_btree_node_relock(struct btree_trans *, struct btree_path *, unsigned, bool trace);
 
 static inline bool bch2_btree_node_relock(struct btree_trans *trans,
 					  struct btree_path *path, unsigned level)
@@ -328,7 +328,19 @@ static inline bool bch2_btree_node_relock(struct btree_trans *trans,
 
 	return likely(btree_node_locked(path, level)) ||
 		(!IS_ERR_OR_NULL(path->l[level].b) &&
-		 __bch2_btree_node_relock(trans, path, level));
+		 __bch2_btree_node_relock(trans, path, level, true));
+}
+
+static inline bool bch2_btree_node_relock_notrace(struct btree_trans *trans,
+						  struct btree_path *path, unsigned level)
+{
+	EBUG_ON(btree_node_locked(path, level) &&
+		!btree_node_write_locked(path, level) &&
+		btree_node_locked_type(path, level) != __btree_lock_want(path, level));
+
+	return likely(btree_node_locked(path, level)) ||
+		(!IS_ERR_OR_NULL(path->l[level].b) &&
+		 __bch2_btree_node_relock(trans, path, level, false));
 }
 
 /* upgrade */