bcachefs: Also show when blocked on write locks

This consolidates some of the btree node lock path, so that when we're
blocked taking a write lock on a node it shows up in
bch2_btree_trans_to_text(), along with intent and read locks.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

fs/bcachefs/btree_iter.c

@@ -150,7 +150,7 @@ void __bch2_btree_node_lock_write(struct btree_trans *trans, struct btree *b)
 	else
 		this_cpu_sub(*b->c.lock.readers, readers);
 
-	btree_node_lock_type(trans->c, b, SIX_LOCK_write);
+	six_lock_write(&b->c.lock, NULL, NULL);
 
 	if (!b->c.lock.readers)
 		atomic64_add(__SIX_VAL(read_lock, readers),
@@ -289,9 +289,7 @@ bool __bch2_btree_node_lock(struct btree_trans *trans,
 			    unsigned long ip)
 {
 	struct btree_path *linked, *deadlock_path = NULL;
-	u64 start_time = local_clock();
 	unsigned reason = 9;
-	bool ret;
 
 	/* Check if it's safe to block: */
 	trans_for_each_path(trans, linked) {
@@ -368,23 +366,8 @@ bool __bch2_btree_node_lock(struct btree_trans *trans,
 		return false;
 	}
 
-	if (six_trylock_type(&b->c.lock, type))
-		return true;
-
-	trans->locking_path_idx = path->idx;
-	trans->locking_pos	= pos;
-	trans->locking_btree_id	= path->btree_id;
-	trans->locking_level	= level;
-	trans->locking		= b;
-
-	ret = six_lock_type(&b->c.lock, type, should_sleep_fn, p) == 0;
-
-	trans->locking = NULL;
-
-	if (ret)
-		bch2_time_stats_update(&trans->c->times[lock_to_time_stat(type)],
-				       start_time);
-	return ret;
+	return btree_node_lock_type(trans, path, b, pos, level,
+				    type, should_sleep_fn, p);
 }
 
 /* Btree iterator locking: */
@@ -3191,6 +3174,7 @@ void bch2_btree_trans_to_text(struct printbuf *out, struct bch_fs *c)
 	struct btree_trans *trans;
 	struct btree_path *path;
 	struct btree *b;
+	static char lock_types[] = { 'r', 'i', 'w' };
 	unsigned l;
 
 	mutex_lock(&c->btree_trans_lock);
@@ -3227,10 +3211,11 @@ void bch2_btree_trans_to_text(struct printbuf *out, struct bch_fs *c)
 		b = READ_ONCE(trans->locking);
 		if (b) {
 			path = &trans->paths[trans->locking_path_idx];
-			pr_buf(out, "  locking path %u %c l=%u %s:",
+			pr_buf(out, "  locking path %u %c l=%u %c %s:",
 			       trans->locking_path_idx,
 			       path->cached ? 'c' : 'b',
 			       trans->locking_level,
+			       lock_types[trans->locking_lock_type],
 			       bch2_btree_ids[trans->locking_btree_id]);
 			bch2_bpos_to_text(out, trans->locking_pos);
 

fs/bcachefs/btree_locking.h

@@ -127,23 +127,35 @@ static inline enum bch_time_stats lock_to_time_stat(enum six_lock_type type)
 	}
 }
 
-/*
- * wrapper around six locks that just traces lock contended time
- */
-static inline void __btree_node_lock_type(struct bch_fs *c, struct btree *b,
-					  enum six_lock_type type)
-{
-	u64 start_time = local_clock();
-
-	six_lock_type(&b->c.lock, type, NULL, NULL);
-	bch2_time_stats_update(&c->times[lock_to_time_stat(type)], start_time);
-}
-
-static inline void btree_node_lock_type(struct bch_fs *c, struct btree *b,
-					enum six_lock_type type)
-{
-	if (!six_trylock_type(&b->c.lock, type))
-		__btree_node_lock_type(c, b, type);
+static inline bool btree_node_lock_type(struct btree_trans *trans,
+				       struct btree_path *path,
+				       struct btree *b,
+				       struct bpos pos, unsigned level,
+				       enum six_lock_type type,
+				       six_lock_should_sleep_fn should_sleep_fn, void *p)
+{
+	struct bch_fs *c = trans->c;
+	u64 start_time;
+	bool ret;
+
+	if (six_trylock_type(&b->c.lock, type))
+		return true;
+
+	start_time = local_clock();
+
+	trans->locking_path_idx = path->idx;
+	trans->locking_pos	= pos;
+	trans->locking_btree_id	= path->btree_id;
+	trans->locking_level	= level;
+	trans->locking_lock_type = type;
+	trans->locking		= b;
+	ret = six_lock_type(&b->c.lock, type, should_sleep_fn, p) == 0;
+	trans->locking = NULL;
+
+	if (ret)
+		bch2_time_stats_update(&c->times[lock_to_time_stat(type)], start_time);
+
+	return ret;
 }
 
 /*

fs/bcachefs/btree_types.h

@@ -383,6 +383,7 @@ struct btree_trans {
 	struct bpos		locking_pos;
 	u8			locking_btree_id;
 	u8			locking_level;
+	u8			locking_lock_type;
 	pid_t			pid;
 	int			srcu_idx;
 

fs/bcachefs/btree_update_interior.c

@@ -607,8 +607,8 @@ static void btree_update_nodes_written(struct btree_update *as)
 		 * we're in journal error state:
 		 */
 
-		btree_node_lock_type(c, b, SIX_LOCK_intent);
-		btree_node_lock_type(c, b, SIX_LOCK_write);
+		six_lock_intent(&b->c.lock, NULL, NULL);
+		six_lock_write(&b->c.lock, NULL, NULL);
 		mutex_lock(&c->btree_interior_update_lock);
 
 		list_del(&as->write_blocked_list);
@@ -662,7 +662,7 @@ static void btree_update_nodes_written(struct btree_update *as)
 	for (i = 0; i < as->nr_new_nodes; i++) {
 		b = as->new_nodes[i];
 
-		btree_node_lock_type(c, b, SIX_LOCK_read);
+		six_lock_read(&b->c.lock, NULL, NULL);
 		btree_node_write_if_need(c, b, SIX_LOCK_read);
 		six_unlock_read(&b->c.lock);
 	}

fs/bcachefs/btree_update_leaf.c

@@ -169,7 +169,7 @@ static int __btree_node_flush(struct journal *j, struct journal_entry_pin *pin,
 	struct btree_write *w = container_of(pin, struct btree_write, journal);
 	struct btree *b = container_of(w, struct btree, writes[i]);
 
-	btree_node_lock_type(c, b, SIX_LOCK_read);
+	six_lock_read(&b->c.lock, NULL, NULL);
 	bch2_btree_node_write_cond(c, b,
 		(btree_current_write(b) == w && w->journal.seq == seq));
 	six_unlock_read(&b->c.lock);
@@ -626,8 +626,10 @@ static inline int trans_lock_write(struct btree_trans *trans)
 			if (have_conflicting_read_lock(trans, i->path))
 				goto fail;
 
-			__btree_node_lock_type(trans->c, insert_l(i)->b,
-					       SIX_LOCK_write);
+			btree_node_lock_type(trans, i->path,
+					     insert_l(i)->b,
+					     i->path->pos, i->level,
+					     SIX_LOCK_write, NULL, NULL);
 		}
 
 		bch2_btree_node_prep_for_write(trans, i->path, insert_l(i)->b);