1 files changed, 121 insertions, 144 deletions

diff --git a/fs/bcachefs/btree_iter.h b/fs/bcachefs/btree_iter.h
index 4ba55e02d4b7..983d61122458 100644
--- a/fs/bcachefs/btree_iter.h
+++ b/fs/bcachefs/btree_iter.h
@@ -5,40 +5,49 @@
 #include "bset.h"
 #include "btree_types.h"
 
-static inline void btree_iter_set_dirty(struct btree_iter *iter,
-					enum btree_iter_uptodate u)
+static inline void __btree_path_get(struct btree_path *path, bool intent)
 {
-	iter->uptodate = max_t(unsigned, iter->uptodate, u);
+	path->ref++;
+	path->intent_ref += intent;
 }
 
-static inline struct btree *btree_iter_node(struct btree_iter *iter,
+static inline bool __btree_path_put(struct btree_path *path, bool intent)
+{
+	EBUG_ON(!path->ref);
+	EBUG_ON(!path->intent_ref && intent);
+	path->intent_ref -= intent;
+	return --path->ref == 0;
+}
+
+static inline void btree_path_set_dirty(struct btree_path *path,
+					enum btree_path_uptodate u)
+{
+	path->uptodate = max_t(unsigned, path->uptodate, u);
+}
+
+static inline struct btree *btree_path_node(struct btree_path *path,
 					    unsigned level)
 {
-	return level < BTREE_MAX_DEPTH ? iter->l[level].b : NULL;
+	return level < BTREE_MAX_DEPTH ? path->l[level].b : NULL;
 }
 
-static inline bool btree_node_lock_seq_matches(const struct btree_iter *iter,
+static inline bool btree_node_lock_seq_matches(const struct btree_path *path,
 					const struct btree *b, unsigned level)
 {
 	/*
 	 * We don't compare the low bits of the lock sequence numbers because
-	 * @iter might have taken a write lock on @b, and we don't want to skip
-	 * the linked iterator if the sequence numbers were equal before taking
-	 * that write lock. The lock sequence number is incremented by taking
-	 * and releasing write locks and is even when unlocked:
+	 * @path might have taken a write lock on @b, and we don't want to skip
+	 * the linked path if the sequence numbers were equal before taking that
+	 * write lock. The lock sequence number is incremented by taking and
+	 * releasing write locks and is even when unlocked:
 	 */
-	return iter->l[level].lock_seq >> 1 == b->c.lock.state.seq >> 1;
+	return path->l[level].lock_seq >> 1 == b->c.lock.state.seq >> 1;
 }
 
-static inline struct btree *btree_node_parent(struct btree_iter *iter,
+static inline struct btree *btree_node_parent(struct btree_path *path,
 					      struct btree *b)
 {
-	return btree_iter_node(iter, b->c.level + 1);
-}
-
-static inline bool btree_trans_has_multiple_iters(const struct btree_trans *trans)
-{
-	return hweight64(trans->iters_linked) > 1;
+	return btree_path_node(path, b->c.level + 1);
 }
 
 static inline int btree_iter_err(const struct btree_iter *iter)
@@ -46,102 +55,121 @@ static inline int btree_iter_err(const struct btree_iter *iter)
 	return iter->flags & BTREE_ITER_ERROR ? -EIO : 0;
 }
 
-/* Iterate over iters within a transaction: */
+/* Iterate over paths within a transaction: */
 
-static inline struct btree_iter *
-__trans_next_iter(struct btree_trans *trans, unsigned idx)
+static inline struct btree_path *
+__trans_next_path(struct btree_trans *trans, unsigned idx)
 {
 	u64 l;
 
 	if (idx == BTREE_ITER_MAX)
 		return NULL;
 
-	l = trans->iters_linked >> idx;
+	l = trans->paths_allocated >> idx;
 	if (!l)
 		return NULL;
 
 	idx += __ffs64(l);
 	EBUG_ON(idx >= BTREE_ITER_MAX);
-	EBUG_ON(trans->iters[idx].idx != idx);
-	return &trans->iters[idx];
+	EBUG_ON(trans->paths[idx].idx != idx);
+	return &trans->paths[idx];
 }
 
-#define trans_for_each_iter(_trans, _iter)				\
-	for (_iter = __trans_next_iter((_trans), 0);			\
-	     (_iter);							\
-	     _iter = __trans_next_iter((_trans), (_iter)->idx + 1))
+#define trans_for_each_path(_trans, _path)				\
+	for (_path = __trans_next_path((_trans), 0);			\
+	     (_path);							\
+	     _path = __trans_next_path((_trans), (_path)->idx + 1))
 
-static inline struct btree_iter *next_btree_iter(struct btree_trans *trans, struct btree_iter *iter)
+static inline struct btree_path *next_btree_path(struct btree_trans *trans, struct btree_path *path)
 {
-	unsigned idx = iter ? iter->sorted_idx + 1 : 0;
+	unsigned idx = path ? path->sorted_idx + 1 : 0;
 
 	EBUG_ON(idx > trans->nr_sorted);
 
 	return idx < trans->nr_sorted
-		? trans->iters + trans->sorted[idx]
+		? trans->paths + trans->sorted[idx]
 		: NULL;
 }
 
-static inline struct btree_iter *prev_btree_iter(struct btree_trans *trans, struct btree_iter *iter)
+static inline struct btree_path *prev_btree_path(struct btree_trans *trans, struct btree_path *path)
 {
-	unsigned idx = iter ? iter->sorted_idx : trans->nr_sorted;
+	unsigned idx = path ? path->sorted_idx : trans->nr_sorted;
 
 	return idx
-		? trans->iters + trans->sorted[idx - 1]
+		? trans->paths + trans->sorted[idx - 1]
 		: NULL;
 }
 
-#define trans_for_each_iter_inorder(_trans, _iter, _i)			\
+#define trans_for_each_path_inorder(_trans, _path, _i)			\
 	for (_i = 0;							\
-	     ((_iter) = (_trans)->iters + trans->sorted[_i]), (_i) < (_trans)->nr_sorted;\
+	     ((_path) = (_trans)->paths + trans->sorted[_i]), (_i) < (_trans)->nr_sorted;\
 	     _i++)
 
-#define trans_for_each_iter_inorder_reverse(_trans, _iter, _i)		\
+#define trans_for_each_path_inorder_reverse(_trans, _path, _i)		\
 	for (_i = trans->nr_sorted - 1;					\
-	     ((_iter) = (_trans)->iters + trans->sorted[_i]), (_i) >= 0;\
+	     ((_path) = (_trans)->paths + trans->sorted[_i]), (_i) >= 0;\
 	     --_i)
 
-static inline bool __iter_has_node(const struct btree_iter *iter,
+static inline bool __path_has_node(const struct btree_path *path,
 				   const struct btree *b)
 {
-	return iter->l[b->c.level].b == b &&
-		btree_node_lock_seq_matches(iter, b, b->c.level);
+	return path->l[b->c.level].b == b &&
+		btree_node_lock_seq_matches(path, b, b->c.level);
 }
 
-static inline struct btree_iter *
-__trans_next_iter_with_node(struct btree_trans *trans, struct btree *b,
+static inline struct btree_path *
+__trans_next_path_with_node(struct btree_trans *trans, struct btree *b,
 			    unsigned idx)
 {
-	struct btree_iter *iter = __trans_next_iter(trans, idx);
+	struct btree_path *path = __trans_next_path(trans, idx);
+
+	while (path && !__path_has_node(path, b))
+		path = __trans_next_path(trans, path->idx + 1);
 
-	while (iter && !__iter_has_node(iter, b))
-		iter = __trans_next_iter(trans, iter->idx + 1);
+	return path;
+}
+
+#define trans_for_each_path_with_node(_trans, _b, _path)		\
+	for (_path = __trans_next_path_with_node((_trans), (_b), 0);	\
+	     (_path);							\
+	     _path = __trans_next_path_with_node((_trans), (_b),	\
+						 (_path)->idx + 1))
+
+struct btree_path *__bch2_btree_path_make_mut(struct btree_trans *,
+					      struct btree_path *, bool);
 
-	return iter;
+static inline struct btree_path * __must_check
+bch2_btree_path_make_mut(struct btree_trans *trans,
+			 struct btree_path *path, bool intent)
+{
+	if (path->ref > 1 || path->preserve)
+		path = __bch2_btree_path_make_mut(trans, path, intent);
+	return path;
 }
 
-#define trans_for_each_iter_with_node(_trans, _b, _iter)		\
-	for (_iter = __trans_next_iter_with_node((_trans), (_b), 0);	\
-	     (_iter);							\
-	     _iter = __trans_next_iter_with_node((_trans), (_b),	\
-						 (_iter)->idx + 1))
+int __must_check bch2_btree_path_traverse(struct btree_trans *,
+					  struct btree_path *, unsigned);
+struct btree_path *bch2_path_get(struct btree_trans *, bool, enum btree_id,
+				 struct bpos, unsigned, unsigned, bool);
+inline struct bkey_s_c bch2_btree_path_peek_slot(struct btree_path *, struct bkey *);
 
 #ifdef CONFIG_BCACHEFS_DEBUG
-void bch2_trans_verify_iters(struct btree_trans *, struct btree *);
+void bch2_trans_verify_paths(struct btree_trans *);
 void bch2_trans_verify_locks(struct btree_trans *);
 #else
-static inline void bch2_trans_verify_iters(struct btree_trans *trans,
-					   struct btree *b) {}
-static inline void bch2_trans_verify_locks(struct btree_trans *iter) {}
+static inline void bch2_trans_verify_paths(struct btree_trans *trans) {}
+static inline void bch2_trans_verify_locks(struct btree_trans *trans) {}
 #endif
 
-void bch2_btree_iter_fix_key_modified(struct btree_trans *trans,
+void bch2_btree_path_fix_key_modified(struct btree_trans *trans,
 				      struct btree *, struct bkey_packed *);
-void bch2_btree_node_iter_fix(struct btree_trans *trans, struct btree_iter *,
+void bch2_btree_node_iter_fix(struct btree_trans *trans, struct btree_path *,
 			      struct btree *, struct btree_node_iter *,
 			      struct bkey_packed *, unsigned, unsigned);
 
-bool bch2_btree_iter_relock_intent(struct btree_trans *, struct btree_iter *);
+bool bch2_btree_path_relock_intent(struct btree_trans *, struct btree_path *);
+
+void bch2_path_put(struct btree_trans *, struct btree_path *, bool);
 
 bool bch2_trans_relock(struct btree_trans *);
 void bch2_trans_unlock(struct btree_trans *);
@@ -154,28 +182,28 @@ static inline int btree_trans_restart(struct btree_trans *trans)
 	return -EINTR;
 }
 
-bool __bch2_btree_iter_upgrade(struct btree_trans *,
-			       struct btree_iter *, unsigned);
+bool __bch2_btree_path_upgrade(struct btree_trans *,
+			       struct btree_path *, unsigned);
 
-static inline bool bch2_btree_iter_upgrade(struct btree_trans *trans,
-					   struct btree_iter *iter,
+static inline bool bch2_btree_path_upgrade(struct btree_trans *trans,
+					   struct btree_path *path,
 					   unsigned new_locks_want)
 {
 	new_locks_want = min(new_locks_want, BTREE_MAX_DEPTH);
 
-	return iter->locks_want < new_locks_want
-		? __bch2_btree_iter_upgrade(trans, iter, new_locks_want)
-		: iter->uptodate == BTREE_ITER_UPTODATE;
+	return path->locks_want < new_locks_want
+		? __bch2_btree_path_upgrade(trans, path, new_locks_want)
+		: path->uptodate == BTREE_ITER_UPTODATE;
 }
 
-void __bch2_btree_iter_downgrade(struct btree_iter *, unsigned);
+void __bch2_btree_path_downgrade(struct btree_path *, unsigned);
 
-static inline void bch2_btree_iter_downgrade(struct btree_iter *iter)
+static inline void bch2_btree_path_downgrade(struct btree_path *path)
 {
-	unsigned new_locks_want = iter->level + !!(iter->flags & BTREE_ITER_INTENT);
+	unsigned new_locks_want = path->level + !!path->intent_ref;
 
-	if (iter->locks_want > new_locks_want)
-		__bch2_btree_iter_downgrade(iter, new_locks_want);
+	if (path->locks_want > new_locks_want)
+		__bch2_btree_path_downgrade(path, new_locks_want);
 }
 
 void bch2_trans_downgrade(struct btree_trans *);
@@ -212,7 +240,8 @@ static inline void bch2_btree_iter_set_pos(struct btree_iter *iter, struct bpos
 	iter->k.p.offset	= iter->pos.offset	= new_pos.offset;
 	iter->k.p.snapshot	= iter->pos.snapshot	= new_pos.snapshot;
 	iter->k.size = 0;
-	iter->should_be_locked = false;
+	if (iter->path->ref == 1)
+		iter->path->should_be_locked = false;
 }
 
 static inline void bch2_btree_iter_set_pos_to_extent_start(struct btree_iter *iter)
@@ -221,17 +250,6 @@ static inline void bch2_btree_iter_set_pos_to_extent_start(struct btree_iter *it
 	iter->pos = bkey_start_pos(&iter->k);
 }
 
-static inline struct btree_iter *idx_to_btree_iter(struct btree_trans *trans, unsigned idx)
-{
-	return idx != U8_MAX ? trans->iters + idx : NULL;
-}
-
-static inline struct btree_iter *btree_iter_child(struct btree_trans *trans,
-						  struct btree_iter *iter)
-{
-	return idx_to_btree_iter(trans, iter->child_idx);
-}
-
 /*
  * Unlocks before scheduling
  * Note: does not revalidate iterator
@@ -249,11 +267,11 @@ static inline int bch2_trans_cond_resched(struct btree_trans *trans)
 
 #define __for_each_btree_node(_trans, _iter, _btree_id, _start,	\
 			      _locks_want, _depth, _flags, _b)		\
-	for (iter = bch2_trans_get_node_iter((_trans), (_btree_id),	\
+	for (bch2_trans_node_iter_init((_trans), &(_iter), (_btree_id),	\
 				_start, _locks_want, _depth, _flags),	\
-	     _b = bch2_btree_iter_peek_node(_iter);			\
+	     _b = bch2_btree_iter_peek_node(&(_iter));			\
 	     (_b);							\
-	     (_b) = bch2_btree_iter_next_node(_iter))
+	     (_b) = bch2_btree_iter_next_node(&(_iter)))
 
 #define for_each_btree_node(_trans, _iter, _btree_id, _start,		\
 			    _flags, _b)					\
@@ -283,77 +301,36 @@ static inline int bkey_err(struct bkey_s_c k)
 
 #define for_each_btree_key(_trans, _iter, _btree_id,			\
 			   _start, _flags, _k, _ret)			\
-	for ((_iter) = bch2_trans_get_iter((_trans), (_btree_id),	\
-					   (_start), (_flags)),		\
-	     (_k) = __bch2_btree_iter_peek(_iter, _flags);		\
+	for (bch2_trans_iter_init((_trans), &(_iter), (_btree_id),	\
+				  (_start), (_flags)),			\
+	     (_k) = __bch2_btree_iter_peek(&(_iter), _flags);		\
 	     !((_ret) = bkey_err(_k)) && (_k).k;			\
-	     (_k) = __bch2_btree_iter_next(_iter, _flags))
+	     (_k) = __bch2_btree_iter_next(&(_iter), _flags))
 
 #define for_each_btree_key_continue(_iter, _flags, _k, _ret)		\
-	for ((_k) = __bch2_btree_iter_peek(_iter, _flags);		\
+	for ((_k) = __bch2_btree_iter_peek(&(_iter), _flags);		\
 	     !((_ret) = bkey_err(_k)) && (_k).k;			\
-	     (_k) = __bch2_btree_iter_next(_iter, _flags))
+	     (_k) = __bch2_btree_iter_next(&(_iter), _flags))
 
 /* new multiple iterator interface: */
 
-void bch2_dump_trans_iters_updates(struct btree_trans *);
-
-int bch2_trans_iter_put(struct btree_trans *, struct btree_iter *);
-int bch2_trans_iter_free(struct btree_trans *, struct btree_iter *);
-
-void bch2_trans_unlink_iters(struct btree_trans *);
-
-struct btree_iter *__bch2_trans_get_iter(struct btree_trans *, enum btree_id,
-					 struct bpos, unsigned,
-					 unsigned, unsigned);
-
-static inline struct btree_iter *
-bch2_trans_get_iter(struct btree_trans *trans, enum btree_id btree_id,
-		    struct bpos pos, unsigned flags)
-{
-	struct btree_iter *iter =
-		__bch2_trans_get_iter(trans, btree_id, pos,
-				      (flags & BTREE_ITER_INTENT) != 0, 0,
-				      flags);
-	iter->ip_allocated = _THIS_IP_;
-	return iter;
-}
-
-struct btree_iter *__bch2_trans_copy_iter(struct btree_trans *,
-					  struct btree_iter *);
-static inline struct btree_iter *
-bch2_trans_copy_iter(struct btree_trans *trans, struct btree_iter *src)
-{
-	struct btree_iter *iter =
-		__bch2_trans_copy_iter(trans, src);
-
-	iter->ip_allocated = _THIS_IP_;
-	return iter;
-}
-
-struct btree_iter *bch2_trans_get_node_iter(struct btree_trans *,
-				enum btree_id, struct bpos,
-				unsigned, unsigned, unsigned);
-
-static inline bool btree_iter_live(struct btree_trans *trans, struct btree_iter *iter)
-{
-	return (trans->iters_live & (1ULL << iter->idx)) != 0;
-}
+void bch2_dump_trans_paths_updates(struct btree_trans *);
 
-static inline bool btree_iter_keep(struct btree_trans *trans, struct btree_iter *iter)
-{
-	return btree_iter_live(trans, iter) ||
-		(iter->flags & BTREE_ITER_KEEP_UNTIL_COMMIT);
-}
+void bch2_trans_iter_exit(struct btree_trans *, struct btree_iter *);
+void bch2_trans_iter_init(struct btree_trans *, struct btree_iter *,
+			  unsigned, struct bpos, unsigned);
+void bch2_trans_node_iter_init(struct btree_trans *, struct btree_iter *,
+			       enum btree_id, struct bpos,
+			       unsigned, unsigned, unsigned);
+void bch2_trans_copy_iter(struct btree_iter *, struct btree_iter *);
 
-static inline void set_btree_iter_dontneed(struct btree_trans *trans, struct btree_iter *iter)
+static inline void set_btree_iter_dontneed(struct btree_iter *iter)
 {
-	trans->iters_touched &= ~(1ULL << iter->idx);
+	iter->path->preserve = false;
 }
 
-void bch2_trans_begin(struct btree_trans *);
-
 void *bch2_trans_kmalloc(struct btree_trans *, size_t);
+void bch2_trans_begin(struct btree_trans *);
 void bch2_trans_init(struct btree_trans *, struct bch_fs *, unsigned, size_t);
 int bch2_trans_exit(struct btree_trans *);