bcachefs: Initial commit

Initially forked from drivers/md/bcache, bcachefs is a new copy-on-write
filesystem with every feature you could possibly want.

Website: https://bcachefs.org

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

1 files changed, 668 insertions, 0 deletions

diff --git a/fs/bcachefs/bset.h b/fs/bcachefs/bset.h
new file mode 100644
index 000000000000..2fa71d7c0e8a
--- /dev/null
+++ b/fs/bcachefs/bset.h
@@ -0,0 +1,668 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _BCACHEFS_BSET_H
+#define _BCACHEFS_BSET_H
+
+#include <linux/kernel.h>
+#include <linux/types.h>
+
+#include "bcachefs_format.h"
+#include "bkey.h"
+#include "bkey_methods.h"
+#include "btree_types.h"
+#include "util.h" /* for time_stats */
+#include "vstructs.h"
+
+/*
+ * BKEYS:
+ *
+ * A bkey contains a key, a size field, a variable number of pointers, and some
+ * ancillary flag bits.
+ *
+ * We use two different functions for validating bkeys, bkey_invalid and
+ * bkey_deleted().
+ *
+ * The one exception to the rule that ptr_invalid() filters out invalid keys is
+ * that it also filters out keys of size 0 - these are keys that have been
+ * completely overwritten. It'd be safe to delete these in memory while leaving
+ * them on disk, just unnecessary work - so we filter them out when resorting
+ * instead.
+ *
+ * We can't filter out stale keys when we're resorting, because garbage
+ * collection needs to find them to ensure bucket gens don't wrap around -
+ * unless we're rewriting the btree node those stale keys still exist on disk.
+ *
+ * We also implement functions here for removing some number of sectors from the
+ * front or the back of a bkey - this is mainly used for fixing overlapping
+ * extents, by removing the overlapping sectors from the older key.
+ *
+ * BSETS:
+ *
+ * A bset is an array of bkeys laid out contiguously in memory in sorted order,
+ * along with a header. A btree node is made up of a number of these, written at
+ * different times.
+ *
+ * There could be many of them on disk, but we never allow there to be more than
+ * 4 in memory - we lazily resort as needed.
+ *
+ * We implement code here for creating and maintaining auxiliary search trees
+ * (described below) for searching an individial bset, and on top of that we
+ * implement a btree iterator.
+ *
+ * BTREE ITERATOR:
+ *
+ * Most of the code in bcache doesn't care about an individual bset - it needs
+ * to search entire btree nodes and iterate over them in sorted order.
+ *
+ * The btree iterator code serves both functions; it iterates through the keys
+ * in a btree node in sorted order, starting from either keys after a specific
+ * point (if you pass it a search key) or the start of the btree node.
+ *
+ * AUXILIARY SEARCH TREES:
+ *
+ * Since keys are variable length, we can't use a binary search on a bset - we
+ * wouldn't be able to find the start of the next key. But binary searches are
+ * slow anyways, due to terrible cache behaviour; bcache originally used binary
+ * searches and that code topped out at under 50k lookups/second.
+ *
+ * So we need to construct some sort of lookup table. Since we only insert keys
+ * into the last (unwritten) set, most of the keys within a given btree node are
+ * usually in sets that are mostly constant. We use two different types of
+ * lookup tables to take advantage of this.
+ *
+ * Both lookup tables share in common that they don't index every key in the
+ * set; they index one key every BSET_CACHELINE bytes, and then a linear search
+ * is used for the rest.
+ *
+ * For sets that have been written to disk and are no longer being inserted
+ * into, we construct a binary search tree in an array - traversing a binary
+ * search tree in an array gives excellent locality of reference and is very
+ * fast, since both children of any node are adjacent to each other in memory
+ * (and their grandchildren, and great grandchildren...) - this means
+ * prefetching can be used to great effect.
+ *
+ * It's quite useful performance wise to keep these nodes small - not just
+ * because they're more likely to be in L2, but also because we can prefetch
+ * more nodes on a single cacheline and thus prefetch more iterations in advance
+ * when traversing this tree.
+ *
+ * Nodes in the auxiliary search tree must contain both a key to compare against
+ * (we don't want to fetch the key from the set, that would defeat the purpose),
+ * and a pointer to the key. We use a few tricks to compress both of these.
+ *
+ * To compress the pointer, we take advantage of the fact that one node in the
+ * search tree corresponds to precisely BSET_CACHELINE bytes in the set. We have
+ * a function (to_inorder()) that takes the index of a node in a binary tree and
+ * returns what its index would be in an inorder traversal, so we only have to
+ * store the low bits of the offset.
+ *
+ * The key is 84 bits (KEY_DEV + key->key, the offset on the device). To
+ * compress that,  we take advantage of the fact that when we're traversing the
+ * search tree at every iteration we know that both our search key and the key
+ * we're looking for lie within some range - bounded by our previous
+ * comparisons. (We special case the start of a search so that this is true even
+ * at the root of the tree).
+ *
+ * So we know the key we're looking for is between a and b, and a and b don't
+ * differ higher than bit 50, we don't need to check anything higher than bit
+ * 50.
+ *
+ * We don't usually need the rest of the bits, either; we only need enough bits
+ * to partition the key range we're currently checking.  Consider key n - the
+ * key our auxiliary search tree node corresponds to, and key p, the key
+ * immediately preceding n.  The lowest bit we need to store in the auxiliary
+ * search tree is the highest bit that differs between n and p.
+ *
+ * Note that this could be bit 0 - we might sometimes need all 80 bits to do the
+ * comparison. But we'd really like our nodes in the auxiliary search tree to be
+ * of fixed size.
+ *
+ * The solution is to make them fixed size, and when we're constructing a node
+ * check if p and n differed in the bits we needed them to. If they don't we
+ * flag that node, and when doing lookups we fallback to comparing against the
+ * real key. As long as this doesn't happen to often (and it seems to reliably
+ * happen a bit less than 1% of the time), we win - even on failures, that key
+ * is then more likely to be in cache than if we were doing binary searches all
+ * the way, since we're touching so much less memory.
+ *
+ * The keys in the auxiliary search tree are stored in (software) floating
+ * point, with an exponent and a mantissa. The exponent needs to be big enough
+ * to address all the bits in the original key, but the number of bits in the
+ * mantissa is somewhat arbitrary; more bits just gets us fewer failures.
+ *
+ * We need 7 bits for the exponent and 3 bits for the key's offset (since keys
+ * are 8 byte aligned); using 22 bits for the mantissa means a node is 4 bytes.
+ * We need one node per 128 bytes in the btree node, which means the auxiliary
+ * search trees take up 3% as much memory as the btree itself.
+ *
+ * Constructing these auxiliary search trees is moderately expensive, and we
+ * don't want to be constantly rebuilding the search tree for the last set
+ * whenever we insert another key into it. For the unwritten set, we use a much
+ * simpler lookup table - it's just a flat array, so index i in the lookup table
+ * corresponds to the i range of BSET_CACHELINE bytes in the set. Indexing
+ * within each byte range works the same as with the auxiliary search trees.
+ *
+ * These are much easier to keep up to date when we insert a key - we do it
+ * somewhat lazily; when we shift a key up we usually just increment the pointer
+ * to it, only when it would overflow do we go to the trouble of finding the
+ * first key in that range of bytes again.
+ */
+
+extern bool bch2_expensive_debug_checks;
+
+static inline bool btree_keys_expensive_checks(const struct btree *b)
+{
+#ifdef CONFIG_BCACHEFS_DEBUG
+	return bch2_expensive_debug_checks || *b->expensive_debug_checks;
+#else
+	return false;
+#endif
+}
+
+enum bset_aux_tree_type {
+	BSET_NO_AUX_TREE,
+	BSET_RO_AUX_TREE,
+	BSET_RW_AUX_TREE,
+};
+
+#define BSET_TREE_NR_TYPES	3
+
+#define BSET_NO_AUX_TREE_VAL	(U16_MAX)
+#define BSET_RW_AUX_TREE_VAL	(U16_MAX - 1)
+
+static inline enum bset_aux_tree_type bset_aux_tree_type(const struct bset_tree *t)
+{
+	switch (t->extra) {
+	case BSET_NO_AUX_TREE_VAL:
+		EBUG_ON(t->size);
+		return BSET_NO_AUX_TREE;
+	case BSET_RW_AUX_TREE_VAL:
+		EBUG_ON(!t->size);
+		return BSET_RW_AUX_TREE;
+	default:
+		EBUG_ON(!t->size);
+		return BSET_RO_AUX_TREE;
+	}
+}
+
+typedef void (*compiled_unpack_fn)(struct bkey *, const struct bkey_packed *);
+
+static inline void
+__bkey_unpack_key_format_checked(const struct btree *b,
+			       struct bkey *dst,
+			       const struct bkey_packed *src)
+{
+#ifdef HAVE_BCACHEFS_COMPILED_UNPACK
+	{
+		compiled_unpack_fn unpack_fn = b->aux_data;
+		unpack_fn(dst, src);
+
+		if (btree_keys_expensive_checks(b)) {
+			struct bkey dst2 = __bch2_bkey_unpack_key(&b->format, src);
+
+			/*
+			 * hack around a harmless race when compacting whiteouts
+			 * for a write:
+			 */
+			dst2.needs_whiteout = dst->needs_whiteout;
+
+			BUG_ON(memcmp(dst, &dst2, sizeof(*dst)));
+		}
+	}
+#else
+	*dst = __bch2_bkey_unpack_key(&b->format, src);
+#endif
+}
+
+static inline struct bkey
+bkey_unpack_key_format_checked(const struct btree *b,
+			       const struct bkey_packed *src)
+{
+	struct bkey dst;
+
+	__bkey_unpack_key_format_checked(b, &dst, src);
+	return dst;
+}
+
+static inline void __bkey_unpack_key(const struct btree *b,
+				     struct bkey *dst,
+				     const struct bkey_packed *src)
+{
+	if (likely(bkey_packed(src)))
+		__bkey_unpack_key_format_checked(b, dst, src);
+	else
+		*dst = *packed_to_bkey_c(src);
+}
+
+/**
+ * bkey_unpack_key -- unpack just the key, not the value
+ */
+static inline struct bkey bkey_unpack_key(const struct btree *b,
+					  const struct bkey_packed *src)
+{
+	return likely(bkey_packed(src))
+		? bkey_unpack_key_format_checked(b, src)
+		: *packed_to_bkey_c(src);
+}
+
+static inline struct bpos
+bkey_unpack_pos_format_checked(const struct btree *b,
+			       const struct bkey_packed *src)
+{
+#ifdef HAVE_BCACHEFS_COMPILED_UNPACK
+	return bkey_unpack_key_format_checked(b, src).p;
+#else
+	return __bkey_unpack_pos(&b->format, src);
+#endif
+}
+
+static inline struct bpos bkey_unpack_pos(const struct btree *b,
+					  const struct bkey_packed *src)
+{
+	return likely(bkey_packed(src))
+		? bkey_unpack_pos_format_checked(b, src)
+		: packed_to_bkey_c(src)->p;
+}
+
+/* Disassembled bkeys */
+
+static inline struct bkey_s_c bkey_disassemble(struct btree *b,
+					       const struct bkey_packed *k,
+					       struct bkey *u)
+{
+	__bkey_unpack_key(b, u, k);
+
+	return (struct bkey_s_c) { u, bkeyp_val(&b->format, k), };
+}
+
+/* non const version: */
+static inline struct bkey_s __bkey_disassemble(struct btree *b,
+					       struct bkey_packed *k,
+					       struct bkey *u)
+{
+	__bkey_unpack_key(b, u, k);
+
+	return (struct bkey_s) { .k = u, .v = bkeyp_val(&b->format, k), };
+}
+
+#define for_each_bset(_b, _t)					\
+	for (_t = (_b)->set; _t < (_b)->set + (_b)->nsets; _t++)
+
+static inline bool bset_has_ro_aux_tree(struct bset_tree *t)
+{
+	return bset_aux_tree_type(t) == BSET_RO_AUX_TREE;
+}
+
+static inline bool bset_has_rw_aux_tree(struct bset_tree *t)
+{
+	return bset_aux_tree_type(t) == BSET_RW_AUX_TREE;
+}
+
+static inline void bch2_bset_set_no_aux_tree(struct btree *b,
+					    struct bset_tree *t)
+{
+	BUG_ON(t < b->set);
+
+	for (; t < b->set + ARRAY_SIZE(b->set); t++) {
+		t->size = 0;
+		t->extra = BSET_NO_AUX_TREE_VAL;
+		t->aux_data_offset = U16_MAX;
+	}
+}
+
+static inline void btree_node_set_format(struct btree *b,
+					 struct bkey_format f)
+{
+	int len;
+
+	b->format	= f;
+	b->nr_key_bits	= bkey_format_key_bits(&f);
+
+	len = bch2_compile_bkey_format(&b->format, b->aux_data);
+	BUG_ON(len < 0 || len > U8_MAX);
+
+	b->unpack_fn_len = len;
+
+	bch2_bset_set_no_aux_tree(b, b->set);
+}
+
+static inline struct bset *bset_next_set(struct btree *b,
+					 unsigned block_bytes)
+{
+	struct bset *i = btree_bset_last(b);
+
+	EBUG_ON(!is_power_of_2(block_bytes));
+
+	return ((void *) i) + round_up(vstruct_bytes(i), block_bytes);
+}
+
+void bch2_btree_keys_free(struct btree *);
+int bch2_btree_keys_alloc(struct btree *, unsigned, gfp_t);
+void bch2_btree_keys_init(struct btree *, bool *);
+
+void bch2_bset_init_first(struct btree *, struct bset *);
+void bch2_bset_init_next(struct bch_fs *, struct btree *,
+			 struct btree_node_entry *);
+void bch2_bset_build_aux_tree(struct btree *, struct bset_tree *, bool);
+void bch2_bset_fix_invalidated_key(struct btree *, struct bset_tree *,
+				  struct bkey_packed *);
+
+void bch2_bset_insert(struct btree *, struct btree_node_iter *,
+		     struct bkey_packed *, struct bkey_i *, unsigned);
+void bch2_bset_delete(struct btree *, struct bkey_packed *, unsigned);
+
+/* Bkey utility code */
+
+/* packed or unpacked */
+static inline int bkey_cmp_p_or_unp(const struct btree *b,
+				    const struct bkey_packed *l,
+				    const struct bkey_packed *r_packed,
+				    struct bpos *r)
+{
+	EBUG_ON(r_packed && !bkey_packed(r_packed));
+
+	if (unlikely(!bkey_packed(l)))
+		return bkey_cmp(packed_to_bkey_c(l)->p, *r);
+
+	if (likely(r_packed))
+		return __bch2_bkey_cmp_packed_format_checked(l, r_packed, b);
+
+	return __bch2_bkey_cmp_left_packed_format_checked(b, l, r);
+}
+
+/* Returns true if @k is after iterator position @pos */
+static inline bool btree_iter_pos_cmp_packed(const struct btree *b,
+					     struct bpos *pos,
+					     const struct bkey_packed *k,
+					     bool strictly_greater)
+{
+	int cmp = bkey_cmp_left_packed(b, k, pos);
+
+	return cmp > 0 ||
+		(cmp == 0 && !strictly_greater && !bkey_deleted(k));
+}
+
+static inline bool btree_iter_pos_cmp_p_or_unp(const struct btree *b,
+					struct bpos pos,
+					const struct bkey_packed *pos_packed,
+					const struct bkey_packed *k,
+					bool strictly_greater)
+{
+	int cmp = bkey_cmp_p_or_unp(b, k, pos_packed, &pos);
+
+	return cmp > 0 ||
+		(cmp == 0 && !strictly_greater && !bkey_deleted(k));
+}
+
+struct bset_tree *bch2_bkey_to_bset(struct btree *, struct bkey_packed *);
+
+struct bkey_packed *bch2_bkey_prev_filter(struct btree *, struct bset_tree *,
+					  struct bkey_packed *, unsigned);
+
+static inline struct bkey_packed *
+bch2_bkey_prev_all(struct btree *b, struct bset_tree *t, struct bkey_packed *k)
+{
+	return bch2_bkey_prev_filter(b, t, k, 0);
+}
+
+static inline struct bkey_packed *
+bch2_bkey_prev(struct btree *b, struct bset_tree *t, struct bkey_packed *k)
+{
+	return bch2_bkey_prev_filter(b, t, k, KEY_TYPE_DISCARD + 1);
+}
+
+enum bch_extent_overlap {
+	BCH_EXTENT_OVERLAP_ALL		= 0,
+	BCH_EXTENT_OVERLAP_BACK		= 1,
+	BCH_EXTENT_OVERLAP_FRONT	= 2,
+	BCH_EXTENT_OVERLAP_MIDDLE	= 3,
+};
+
+/* Returns how k overlaps with m */
+static inline enum bch_extent_overlap bch2_extent_overlap(const struct bkey *k,
+							 const struct bkey *m)
+{
+	int cmp1 = bkey_cmp(k->p, m->p) < 0;
+	int cmp2 = bkey_cmp(bkey_start_pos(k),
+			    bkey_start_pos(m)) > 0;
+
+	return (cmp1 << 1) + cmp2;
+}
+
+/* Btree key iteration */
+
+static inline void __bch2_btree_node_iter_init(struct btree_node_iter *iter,
+					      bool is_extents)
+{
+	iter->is_extents = is_extents;
+	memset(iter->data, 0, sizeof(iter->data));
+}
+
+void bch2_btree_node_iter_push(struct btree_node_iter *, struct btree *,
+			      const struct bkey_packed *,
+			      const struct bkey_packed *);
+void bch2_btree_node_iter_init(struct btree_node_iter *, struct btree *,
+			      struct bpos, bool, bool);
+void bch2_btree_node_iter_init_from_start(struct btree_node_iter *,
+					 struct btree *, bool);
+struct bkey_packed *bch2_btree_node_iter_bset_pos(struct btree_node_iter *,
+						 struct btree *,
+						 struct bset_tree *);
+
+void bch2_btree_node_iter_sort(struct btree_node_iter *, struct btree *);
+void bch2_btree_node_iter_set_drop(struct btree_node_iter *,
+				   struct btree_node_iter_set *);
+void bch2_btree_node_iter_advance(struct btree_node_iter *, struct btree *);
+
+#define btree_node_iter_for_each(_iter, _set)				\
+	for (_set = (_iter)->data;					\
+	     _set < (_iter)->data + ARRAY_SIZE((_iter)->data) &&	\
+	     (_set)->k != (_set)->end;					\
+	     _set++)
+
+static inline bool __btree_node_iter_set_end(struct btree_node_iter *iter,
+					     unsigned i)
+{
+	return iter->data[i].k == iter->data[i].end;
+}
+
+static inline bool bch2_btree_node_iter_end(struct btree_node_iter *iter)
+{
+	return __btree_node_iter_set_end(iter, 0);
+}
+
+static inline int __btree_node_iter_cmp(bool is_extents,
+					struct btree *b,
+					struct bkey_packed *l,
+					struct bkey_packed *r)
+{
+	/*
+	 * For non extents, when keys compare equal the deleted keys have to
+	 * come first - so that bch2_btree_node_iter_next_check() can detect
+	 * duplicate nondeleted keys (and possibly other reasons?)
+	 *
+	 * For extents, bkey_deleted() is used as a proxy for k->size == 0, so
+	 * deleted keys have to sort last.
+	 */
+	return bkey_cmp_packed(b, l, r)
+		?: (is_extents
+		    ? (int) bkey_deleted(l) - (int) bkey_deleted(r)
+		    : (int) bkey_deleted(r) - (int) bkey_deleted(l))
+		?: (l > r) - (l < r);
+}
+
+static inline int btree_node_iter_cmp(struct btree_node_iter *iter,
+				      struct btree *b,
+				      struct btree_node_iter_set l,
+				      struct btree_node_iter_set r)
+{
+	return __btree_node_iter_cmp(iter->is_extents, b,
+			__btree_node_offset_to_key(b, l.k),
+			__btree_node_offset_to_key(b, r.k));
+}
+
+static inline void __bch2_btree_node_iter_push(struct btree_node_iter *iter,
+			      struct btree *b,
+			      const struct bkey_packed *k,
+			      const struct bkey_packed *end)
+{
+	if (k != end) {
+		struct btree_node_iter_set *pos;
+
+		btree_node_iter_for_each(iter, pos)
+			;
+
+		BUG_ON(pos >= iter->data + ARRAY_SIZE(iter->data));
+		*pos = (struct btree_node_iter_set) {
+			__btree_node_key_to_offset(b, k),
+			__btree_node_key_to_offset(b, end)
+		};
+	}
+}
+
+static inline struct bkey_packed *
+__bch2_btree_node_iter_peek_all(struct btree_node_iter *iter,
+				struct btree *b)
+{
+	return __btree_node_offset_to_key(b, iter->data->k);
+}
+
+static inline struct bkey_packed *
+bch2_btree_node_iter_peek_filter(struct btree_node_iter *iter,
+				 struct btree *b,
+				 unsigned min_key_type)
+{
+	while (!bch2_btree_node_iter_end(iter)) {
+		struct bkey_packed *k = __bch2_btree_node_iter_peek_all(iter, b);
+
+		if (k->type >= min_key_type)
+			return k;
+
+		bch2_btree_node_iter_advance(iter, b);
+	}
+
+	return NULL;
+}
+
+static inline struct bkey_packed *
+bch2_btree_node_iter_peek_all(struct btree_node_iter *iter,
+			      struct btree *b)
+{
+	return bch2_btree_node_iter_peek_filter(iter, b, 0);
+}
+
+static inline struct bkey_packed *
+bch2_btree_node_iter_peek(struct btree_node_iter *iter, struct btree *b)
+{
+	return bch2_btree_node_iter_peek_filter(iter, b, KEY_TYPE_DISCARD + 1);
+}
+
+static inline struct bkey_packed *
+bch2_btree_node_iter_next_all(struct btree_node_iter *iter, struct btree *b)
+{
+	struct bkey_packed *ret = bch2_btree_node_iter_peek_all(iter, b);
+
+	if (ret)
+		bch2_btree_node_iter_advance(iter, b);
+
+	return ret;
+}
+
+struct bkey_packed *bch2_btree_node_iter_prev_filter(struct btree_node_iter *,
+						     struct btree *, unsigned);
+
+static inline struct bkey_packed *
+bch2_btree_node_iter_prev_all(struct btree_node_iter *iter, struct btree *b)
+{
+	return bch2_btree_node_iter_prev_filter(iter, b, 0);
+}
+
+static inline struct bkey_packed *
+bch2_btree_node_iter_prev(struct btree_node_iter *iter, struct btree *b)
+{
+	return bch2_btree_node_iter_prev_filter(iter, b, KEY_TYPE_DISCARD + 1);
+}
+
+/*
+ * Iterates over all _live_ keys - skipping deleted (and potentially
+ * overlapping) keys
+ */
+#define for_each_btree_node_key(b, k, iter, _is_extents)		\
+	for (bch2_btree_node_iter_init_from_start((iter), (b), (_is_extents));\
+	     ((k) = bch2_btree_node_iter_peek(iter, b));			\
+	     bch2_btree_node_iter_advance(iter, b))
+
+struct bkey_s_c bch2_btree_node_iter_peek_unpack(struct btree_node_iter *,
+						struct btree *,
+						struct bkey *);
+
+#define for_each_btree_node_key_unpack(b, k, iter, _is_extents, unpacked)\
+	for (bch2_btree_node_iter_init_from_start((iter), (b), (_is_extents));\
+	     (k = bch2_btree_node_iter_peek_unpack((iter), (b), (unpacked))).k;\
+	     bch2_btree_node_iter_advance(iter, b))
+
+/* Accounting: */
+
+static inline void btree_keys_account_key(struct btree_nr_keys *n,
+					  unsigned bset,
+					  struct bkey_packed *k,
+					  int sign)
+{
+	n->live_u64s		+= k->u64s * sign;
+	n->bset_u64s[bset]	+= k->u64s * sign;
+
+	if (bkey_packed(k))
+		n->packed_keys	+= sign;
+	else
+		n->unpacked_keys += sign;
+}
+
+#define btree_keys_account_key_add(_nr, _bset_idx, _k)		\
+	btree_keys_account_key(_nr, _bset_idx, _k, 1)
+#define btree_keys_account_key_drop(_nr, _bset_idx, _k)	\
+	btree_keys_account_key(_nr, _bset_idx, _k, -1)
+
+struct bset_stats {
+	struct {
+		size_t nr, bytes;
+	} sets[BSET_TREE_NR_TYPES];
+
+	size_t floats;
+	size_t failed_unpacked;
+	size_t failed_prev;
+	size_t failed_overflow;
+};
+
+void bch2_btree_keys_stats(struct btree *, struct bset_stats *);
+int bch2_bkey_print_bfloat(struct btree *, struct bkey_packed *,
+			  char *, size_t);
+
+/* Debug stuff */
+
+void bch2_dump_bset(struct btree *, struct bset *, unsigned);
+void bch2_dump_btree_node(struct btree *);
+void bch2_dump_btree_node_iter(struct btree *, struct btree_node_iter *);
+
+#ifdef CONFIG_BCACHEFS_DEBUG
+
+void __bch2_verify_btree_nr_keys(struct btree *);
+void bch2_btree_node_iter_verify(struct btree_node_iter *, struct btree *);
+void bch2_verify_key_order(struct btree *, struct btree_node_iter *,
+			  struct bkey_packed *);
+
+#else
+
+static inline void __bch2_verify_btree_nr_keys(struct btree *b) {}
+static inline void bch2_btree_node_iter_verify(struct btree_node_iter *iter,
+					      struct btree *b) {}
+static inline void bch2_verify_key_order(struct btree *b,
+					struct btree_node_iter *iter,
+					struct bkey_packed *where) {}
+#endif
+
+static inline void bch2_verify_btree_nr_keys(struct btree *b)
+{
+	if (btree_keys_expensive_checks(b))
+		__bch2_verify_btree_nr_keys(b);
+}
+
+#endif /* _BCACHEFS_BSET_H */