bcachefs: Convert more locking code to btree_bkey_cached_common

Ideally, all the code in btree_locking.c should be converted, but then
we'd want to convert btree_path to point to btree_key_cached_common too,
and then we'd be in for a much bigger cleanup - but a bit of incremental
cleanup will still be helpful for the next patches.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

fs/bcachefs/btree_key_cache.c

@@ -343,7 +343,7 @@ static int btree_key_cache_fill(struct btree_trans *trans,
 		}
 	}
 
-	ret = bch2_btree_node_lock_write(trans, ck_path, ck_path->l[0].b);
+	ret = bch2_btree_node_lock_write(trans, ck_path, &ck_path->l[0].b->c);
 	if (ret) {
 		kfree(new_k);
 		goto err;

fs/bcachefs/btree_locking.c

@@ -52,9 +52,10 @@ void bch2_btree_node_unlock_write(struct btree_trans *trans,
 
 /* lock */
 
-void __bch2_btree_node_lock_write(struct btree_trans *trans, struct btree *b)
+void __bch2_btree_node_lock_write(struct btree_trans *trans,
+				  struct btree_bkey_cached_common *b)
 {
-	int readers = bch2_btree_node_lock_counts(trans, NULL, &b->c, b->c.level).n[SIX_LOCK_read];
+	int readers = bch2_btree_node_lock_counts(trans, NULL, b, b->level).n[SIX_LOCK_read];
 
 	/*
 	 * Must drop our read locks before calling six_lock_write() -
@@ -62,9 +63,9 @@ void __bch2_btree_node_lock_write(struct btree_trans *trans, struct btree *b)
 	 * goes to 0, and it's safe because we have the node intent
 	 * locked:
 	 */
-	six_lock_readers_add(&b->c.lock, -readers);
-	btree_node_lock_nopath_nofail(trans, &b->c, SIX_LOCK_write);
-	six_lock_readers_add(&b->c.lock, readers);
+	six_lock_readers_add(&b->lock, -readers);
+	btree_node_lock_nopath_nofail(trans, b, SIX_LOCK_write);
+	six_lock_readers_add(&b->lock, readers);
 }
 
 static inline bool path_has_read_locks(struct btree_path *path)

fs/bcachefs/btree_locking.h

@@ -279,31 +279,31 @@ static inline int btree_node_lock(struct btree_trans *trans,
 	return ret;
 }
 
-void __bch2_btree_node_lock_write(struct btree_trans *, struct btree *);
+void __bch2_btree_node_lock_write(struct btree_trans *, struct btree_bkey_cached_common *);
 
 static inline void bch2_btree_node_lock_write_nofail(struct btree_trans *trans,
 					      struct btree_path *path,
-					      struct btree *b)
+					      struct btree_bkey_cached_common *b)
 {
-	EBUG_ON(path->l[b->c.level].b != b);
-	EBUG_ON(path->l[b->c.level].lock_seq != b->c.lock.state.seq);
-	EBUG_ON(!btree_node_intent_locked(path, b->c.level));
+	EBUG_ON(&path->l[b->level].b->c != b);
+	EBUG_ON(path->l[b->level].lock_seq != b->lock.state.seq);
+	EBUG_ON(!btree_node_intent_locked(path, b->level));
 
 	/*
 	 * six locks are unfair, and read locks block while a thread wants a
 	 * write lock: thus, we need to tell the cycle detector we have a write
 	 * lock _before_ taking the lock:
 	 */
-	mark_btree_node_locked_noreset(path, b->c.level, SIX_LOCK_write);
+	mark_btree_node_locked_noreset(path, b->level, SIX_LOCK_write);
 
-	if (unlikely(!six_trylock_write(&b->c.lock)))
+	if (unlikely(!six_trylock_write(&b->lock)))
 		__bch2_btree_node_lock_write(trans, b);
 }
 
 static inline int __must_check
 bch2_btree_node_lock_write(struct btree_trans *trans,
 			   struct btree_path *path,
-			   struct btree *b)
+			   struct btree_bkey_cached_common *b)
 {
 	bch2_btree_node_lock_write_nofail(trans, path, b);
 	return 0;

fs/bcachefs/btree_update_interior.c

@@ -1163,7 +1163,7 @@ static void bch2_btree_set_root(struct btree_update *as,
 	 * Ensure no one is using the old root while we switch to the
 	 * new root:
 	 */
-	bch2_btree_node_lock_write_nofail(trans, path, old);
+	bch2_btree_node_lock_write_nofail(trans, path, &old->c);
 
 	bch2_btree_set_root_inmem(c, b);
 
@@ -2002,7 +2002,7 @@ static int __bch2_btree_node_update_key(struct btree_trans *trans,
 	if (ret)
 		goto err;
 
-	bch2_btree_node_lock_write_nofail(trans, iter->path, b);
+	bch2_btree_node_lock_write_nofail(trans, iter->path, &b->c);
 
 	if (new_hash) {
 		mutex_lock(&c->btree_cache.lock);

fs/bcachefs/btree_update_leaf.c

@@ -81,7 +81,7 @@ void bch2_btree_node_lock_for_insert(struct btree_trans *trans,
 				     struct btree_path *path,
 				     struct btree *b)
 {
-	bch2_btree_node_lock_write_nofail(trans, path, b);
+	bch2_btree_node_lock_write_nofail(trans, path, &b->c);
 	bch2_btree_node_prep_for_write(trans, path, b);
 }