+struct btree_keys_ops {
+ bool (*sort_cmp)(struct btree_iter_set,
+ struct btree_iter_set);
+ struct bkey *(*sort_fixup)(struct btree_iter *, struct bkey *);
+ bool (*key_invalid)(struct btree_keys *,
+ const struct bkey *);
+ bool (*key_bad)(struct btree_keys *, const struct bkey *);
+ bool (*key_merge)(struct btree_keys *,
+ struct bkey *, struct bkey *);
+
+ /*
+ * Only used for deciding whether to use START_KEY(k) or just the key
+ * itself in a couple places
+ */
+ bool is_extents;
+};
+
+struct btree_keys {
+ const struct btree_keys_ops *ops;
+ uint8_t page_order;
+ uint8_t nsets;
+ unsigned last_set_unwritten:1;
+ bool *expensive_debug_checks;
+
+ /*
+ * Sets of sorted keys - the real btree node - plus a binary search tree
+ *
+ * set[0] is special; set[0]->tree, set[0]->prev and set[0]->data point
+ * to the memory we have allocated for this btree node. Additionally,
+ * set[0]->data points to the entire btree node as it exists on disk.
+ */
+ struct bset_tree set[MAX_BSETS];
+};
+
+static inline struct bset_tree *bset_tree_last(struct btree_keys *b)
+{
+ return b->set + b->nsets;
+}
+
+static inline bool bset_written(struct btree_keys *b, struct bset_tree *t)
+{
+ return t <= b->set + b->nsets - b->last_set_unwritten;
+}
+
+static inline bool bkey_written(struct btree_keys *b, struct bkey *k)
+{
+ return !b->last_set_unwritten || k < b->set[b->nsets].data->start;
+}
+
+static inline unsigned bset_byte_offset(struct btree_keys *b, struct bset *i)
+{
+ return ((size_t) i) - ((size_t) b->set->data);
+}
+
+static inline unsigned bset_sector_offset(struct btree_keys *b, struct bset *i)
+{
+ return bset_byte_offset(b, i) >> 9;
+}
+
+static inline bool btree_keys_expensive_checks(struct btree_keys *b)
+{
+#ifdef CONFIG_BCACHE_DEBUG
+ return *b->expensive_debug_checks;
+#else
+ return false;
+#endif
+}
+