1 files changed, 314 insertions, 0 deletions

diff --git a/fs/bcachefs/btree_iter.h b/fs/bcachefs/btree_iter.h
new file mode 100644
index 000000000000..e686a7ad5b3d
--- /dev/null
+++ b/fs/bcachefs/btree_iter.h
@@ -0,0 +1,314 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _BCACHEFS_BTREE_ITER_H
+#define _BCACHEFS_BTREE_ITER_H
+
+#include "btree_types.h"
+
+static inline void btree_iter_set_dirty(struct btree_iter *iter,
+					enum btree_iter_uptodate u)
+{
+	iter->uptodate = max_t(unsigned, iter->uptodate, u);
+}
+
+static inline struct btree *btree_iter_node(struct btree_iter *iter,
+					    unsigned level)
+{
+	return level < BTREE_MAX_DEPTH ? iter->l[level].b : NULL;
+}
+
+static inline struct btree *btree_node_parent(struct btree_iter *iter,
+					      struct btree *b)
+{
+	return btree_iter_node(iter, b->level + 1);
+}
+
+static inline bool btree_iter_linked(const struct btree_iter *iter)
+{
+	return iter->next != iter;
+}
+
+static inline bool __iter_has_node(const struct btree_iter *iter,
+				   const struct btree *b)
+{
+	/*
+	 * 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:
+	 */
+
+	return iter->l[b->level].b == b &&
+		iter->lock_seq[b->level] >> 1 == b->lock.state.seq >> 1;
+}
+
+static inline struct btree_iter *
+__next_linked_iter(struct btree_iter *iter, struct btree_iter *linked)
+{
+	return linked->next != iter ? linked->next : NULL;
+}
+
+static inline struct btree_iter *
+__next_iter_with_node(struct btree_iter *iter, struct btree *b,
+		      struct btree_iter *linked)
+{
+	while (linked && !__iter_has_node(linked, b))
+		linked = __next_linked_iter(iter, linked);
+
+	return linked;
+}
+
+/**
+ * for_each_btree_iter - iterate over all iterators linked with @_iter,
+ * including @_iter
+ */
+#define for_each_btree_iter(_iter, _linked)				\
+	for ((_linked) = (_iter); (_linked);				\
+	     (_linked) = __next_linked_iter(_iter, _linked))
+
+/**
+ * for_each_btree_iter_with_node - iterate over all iterators linked with @_iter
+ * that also point to @_b
+ *
+ * @_b is assumed to be locked by @_iter
+ *
+ * Filters out iterators that don't have a valid btree_node iterator for @_b -
+ * i.e. iterators for which bch2_btree_node_relock() would not succeed.
+ */
+#define for_each_btree_iter_with_node(_iter, _b, _linked)		\
+	for ((_linked) = (_iter);					\
+	     ((_linked) = __next_iter_with_node(_iter, _b, _linked));	\
+	     (_linked) = __next_linked_iter(_iter, _linked))
+
+/**
+ * for_each_linked_btree_iter - iterate over all iterators linked with @_iter,
+ * _not_ including @_iter
+ */
+#define for_each_linked_btree_iter(_iter, _linked)			\
+	for ((_linked) = (_iter)->next;					\
+	     (_linked) != (_iter);					\
+	     (_linked) = (_linked)->next)
+
+#ifdef CONFIG_BCACHEFS_DEBUG
+void bch2_btree_iter_verify(struct btree_iter *, struct btree *);
+void bch2_btree_iter_verify_locks(struct btree_iter *);
+#else
+static inline void bch2_btree_iter_verify(struct btree_iter *iter,
+					  struct btree *b) {}
+static inline void bch2_btree_iter_verify_locks(struct btree_iter *iter) {}
+#endif
+
+void bch2_btree_node_iter_fix(struct btree_iter *, struct btree *,
+			     struct btree_node_iter *, struct bset_tree *,
+			     struct bkey_packed *, unsigned, unsigned);
+
+int bch2_btree_iter_unlock(struct btree_iter *);
+
+bool __bch2_btree_iter_upgrade(struct btree_iter *, unsigned);
+bool __bch2_btree_iter_upgrade_nounlock(struct btree_iter *, unsigned);
+
+static inline bool bch2_btree_iter_upgrade(struct btree_iter *iter,
+					   unsigned new_locks_want,
+					   bool may_drop_locks)
+{
+	new_locks_want = min(new_locks_want, BTREE_MAX_DEPTH);
+
+	return iter->locks_want < new_locks_want
+		? (may_drop_locks
+		   ? __bch2_btree_iter_upgrade(iter, new_locks_want)
+		   : __bch2_btree_iter_upgrade_nounlock(iter, new_locks_want))
+		: iter->uptodate <= BTREE_ITER_NEED_PEEK;
+}
+
+void __bch2_btree_iter_downgrade(struct btree_iter *, unsigned);
+
+static inline void bch2_btree_iter_downgrade(struct btree_iter *iter)
+{
+	if (iter->locks_want > (iter->flags & BTREE_ITER_INTENT) ? 1 : 0)
+		__bch2_btree_iter_downgrade(iter, 0);
+}
+
+void bch2_btree_iter_node_replace(struct btree_iter *, struct btree *);
+void bch2_btree_iter_node_drop(struct btree_iter *, struct btree *);
+
+void bch2_btree_iter_reinit_node(struct btree_iter *, struct btree *);
+
+int __must_check bch2_btree_iter_traverse(struct btree_iter *);
+
+struct btree *bch2_btree_iter_peek_node(struct btree_iter *);
+struct btree *bch2_btree_iter_next_node(struct btree_iter *, unsigned);
+
+struct bkey_s_c bch2_btree_iter_peek(struct btree_iter *);
+struct bkey_s_c bch2_btree_iter_next(struct btree_iter *);
+struct bkey_s_c bch2_btree_iter_prev(struct btree_iter *);
+
+struct bkey_s_c bch2_btree_iter_peek_slot(struct btree_iter *);
+struct bkey_s_c bch2_btree_iter_next_slot(struct btree_iter *);
+
+void bch2_btree_iter_set_pos_same_leaf(struct btree_iter *, struct bpos);
+void bch2_btree_iter_set_pos(struct btree_iter *, struct bpos);
+
+void __bch2_btree_iter_init(struct btree_iter *, struct bch_fs *,
+			   enum btree_id, struct bpos,
+			   unsigned , unsigned, unsigned);
+
+static inline void bch2_btree_iter_init(struct btree_iter *iter,
+			struct bch_fs *c, enum btree_id btree_id,
+			struct bpos pos, unsigned flags)
+{
+	__bch2_btree_iter_init(iter, c, btree_id, pos,
+			       flags & BTREE_ITER_INTENT ? 1 : 0, 0,
+			       (btree_id == BTREE_ID_EXTENTS
+				?  BTREE_ITER_IS_EXTENTS : 0)|flags);
+}
+
+void bch2_btree_iter_link(struct btree_iter *, struct btree_iter *);
+void bch2_btree_iter_unlink(struct btree_iter *);
+void bch2_btree_iter_copy(struct btree_iter *, struct btree_iter *);
+
+static inline struct bpos btree_type_successor(enum btree_id id,
+					       struct bpos pos)
+{
+	if (id == BTREE_ID_INODES) {
+		pos.inode++;
+		pos.offset = 0;
+	} else if (id != BTREE_ID_EXTENTS) {
+		pos = bkey_successor(pos);
+	}
+
+	return pos;
+}
+
+static inline struct bpos btree_type_predecessor(enum btree_id id,
+					       struct bpos pos)
+{
+	if (id == BTREE_ID_INODES) {
+		--pos.inode;
+		pos.offset = 0;
+	} else /* if (id != BTREE_ID_EXTENTS) */ {
+		pos = bkey_predecessor(pos);
+	}
+
+	return pos;
+}
+
+static inline int __btree_iter_cmp(enum btree_id id,
+				   struct bpos pos,
+				   const struct btree_iter *r)
+{
+	if (id != r->btree_id)
+		return id < r->btree_id ? -1 : 1;
+	return bkey_cmp(pos, r->pos);
+}
+
+static inline int btree_iter_cmp(const struct btree_iter *l,
+				 const struct btree_iter *r)
+{
+	return __btree_iter_cmp(l->btree_id, l->pos, r);
+}
+
+/*
+ * Unlocks before scheduling
+ * Note: does not revalidate iterator
+ */
+static inline void bch2_btree_iter_cond_resched(struct btree_iter *iter)
+{
+	if (need_resched()) {
+		bch2_btree_iter_unlock(iter);
+		schedule();
+	} else if (race_fault()) {
+		bch2_btree_iter_unlock(iter);
+	}
+}
+
+#define __for_each_btree_node(_iter, _c, _btree_id, _start,		\
+			      _locks_want, _depth, _flags, _b)		\
+	for (__bch2_btree_iter_init((_iter), (_c), (_btree_id), _start,	\
+				    _locks_want, _depth,		\
+				    _flags|BTREE_ITER_NODES),		\
+	     _b = bch2_btree_iter_peek_node(_iter);			\
+	     (_b);							\
+	     (_b) = bch2_btree_iter_next_node(_iter, _depth))
+
+#define for_each_btree_node(_iter, _c, _btree_id, _start, _flags, _b)	\
+	__for_each_btree_node(_iter, _c, _btree_id, _start, 0, 0, _flags, _b)
+
+static inline struct bkey_s_c __bch2_btree_iter_peek(struct btree_iter *iter,
+						     unsigned flags)
+{
+	return flags & BTREE_ITER_SLOTS
+		? bch2_btree_iter_peek_slot(iter)
+		: bch2_btree_iter_peek(iter);
+}
+
+static inline struct bkey_s_c __bch2_btree_iter_next(struct btree_iter *iter,
+						     unsigned flags)
+{
+	bch2_btree_iter_cond_resched(iter);
+
+	return flags & BTREE_ITER_SLOTS
+		? bch2_btree_iter_next_slot(iter)
+		: bch2_btree_iter_next(iter);
+}
+
+#define for_each_btree_key(_iter, _c, _btree_id,  _start, _flags, _k)	\
+	for (bch2_btree_iter_init((_iter), (_c), (_btree_id),		\
+				  (_start), (_flags)),			\
+	     (_k) = __bch2_btree_iter_peek(_iter, _flags);		\
+	     !IS_ERR_OR_NULL((_k).k);					\
+	     (_k) = __bch2_btree_iter_next(_iter, _flags))
+
+#define for_each_btree_key_continue(_iter, _flags, _k)			\
+	for ((_k) = __bch2_btree_iter_peek(_iter, _flags);		\
+	     !IS_ERR_OR_NULL((_k).k);					\
+	     (_k) = __bch2_btree_iter_next(_iter, _flags))
+
+static inline int btree_iter_err(struct bkey_s_c k)
+{
+	return PTR_ERR_OR_ZERO(k.k);
+}
+
+/* new multiple iterator interface: */
+
+int bch2_trans_preload_iters(struct btree_trans *);
+void bch2_trans_iter_free(struct btree_trans *,
+				struct btree_iter *);
+
+struct btree_iter *__bch2_trans_get_iter(struct btree_trans *, enum btree_id,
+					 struct bpos, unsigned, u64);
+struct btree_iter *__bch2_trans_copy_iter(struct btree_trans *,
+					  struct btree_iter *, u64);
+
+static __always_inline u64 __btree_iter_id(void)
+{
+	u64 ret = 0;
+
+	ret <<= 32;
+	ret |= _RET_IP_ & U32_MAX;
+	ret <<= 32;
+	ret |= _THIS_IP_ & U32_MAX;
+	return ret;
+}
+
+static __always_inline struct btree_iter *
+bch2_trans_get_iter(struct btree_trans *trans, enum btree_id btree_id,
+		    struct bpos pos, unsigned flags)
+{
+	return __bch2_trans_get_iter(trans, btree_id, pos, flags,
+				     __btree_iter_id());
+}
+
+static __always_inline struct btree_iter *
+bch2_trans_copy_iter(struct btree_trans *trans, struct btree_iter *src)
+{
+
+	return __bch2_trans_copy_iter(trans, src, __btree_iter_id());
+}
+
+void *bch2_trans_kmalloc(struct btree_trans *, size_t);
+int bch2_trans_unlock(struct btree_trans *);
+void bch2_trans_begin(struct btree_trans *);
+void bch2_trans_init(struct btree_trans *, struct bch_fs *);
+int bch2_trans_exit(struct btree_trans *);
+
+#endif /* _BCACHEFS_BTREE_ITER_H */