Move c_src dirs back to toplevel

We just wanted c sourcefiles out of the top level, not c source
directories.

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

1 files changed, 0 insertions, 3268 deletions

diff --git a/c_src/libbcachefs/btree_iter.c b/c_src/libbcachefs/btree_iter.c
deleted file mode 100644
index fa298289..00000000
--- a/c_src/libbcachefs/btree_iter.c
+++ /dev/null
@@ -1,3268 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0
-
-#include "bcachefs.h"
-#include "bkey_methods.h"
-#include "bkey_buf.h"
-#include "btree_cache.h"
-#include "btree_iter.h"
-#include "btree_journal_iter.h"
-#include "btree_key_cache.h"
-#include "btree_locking.h"
-#include "btree_update.h"
-#include "debug.h"
-#include "error.h"
-#include "extents.h"
-#include "journal.h"
-#include "journal_io.h"
-#include "replicas.h"
-#include "snapshot.h"
-#include "trace.h"
-
-#include <linux/random.h>
-#include <linux/prefetch.h>
-
-static inline void btree_path_list_remove(struct btree_trans *, struct btree_path *);
-static inline void btree_path_list_add(struct btree_trans *,
-			btree_path_idx_t, btree_path_idx_t);
-
-static inline unsigned long btree_iter_ip_allocated(struct btree_iter *iter)
-{
-#ifdef TRACK_PATH_ALLOCATED
-	return iter->ip_allocated;
-#else
-	return 0;
-#endif
-}
-
-static btree_path_idx_t btree_path_alloc(struct btree_trans *, btree_path_idx_t);
-static void bch2_trans_srcu_lock(struct btree_trans *);
-
-static inline int __btree_path_cmp(const struct btree_path *l,
-				   enum btree_id	r_btree_id,
-				   bool			r_cached,
-				   struct bpos		r_pos,
-				   unsigned		r_level)
-{
-	/*
-	 * Must match lock ordering as defined by __bch2_btree_node_lock:
-	 */
-	return   cmp_int(l->btree_id,	r_btree_id) ?:
-		 cmp_int((int) l->cached,	(int) r_cached) ?:
-		 bpos_cmp(l->pos,	r_pos) ?:
-		-cmp_int(l->level,	r_level);
-}
-
-static inline int btree_path_cmp(const struct btree_path *l,
-				 const struct btree_path *r)
-{
-	return __btree_path_cmp(l, r->btree_id, r->cached, r->pos, r->level);
-}
-
-static inline struct bpos bkey_successor(struct btree_iter *iter, struct bpos p)
-{
-	/* Are we iterating over keys in all snapshots? */
-	if (iter->flags & BTREE_ITER_ALL_SNAPSHOTS) {
-		p = bpos_successor(p);
-	} else {
-		p = bpos_nosnap_successor(p);
-		p.snapshot = iter->snapshot;
-	}
-
-	return p;
-}
-
-static inline struct bpos bkey_predecessor(struct btree_iter *iter, struct bpos p)
-{
-	/* Are we iterating over keys in all snapshots? */
-	if (iter->flags & BTREE_ITER_ALL_SNAPSHOTS) {
-		p = bpos_predecessor(p);
-	} else {
-		p = bpos_nosnap_predecessor(p);
-		p.snapshot = iter->snapshot;
-	}
-
-	return p;
-}
-
-static inline struct bpos btree_iter_search_key(struct btree_iter *iter)
-{
-	struct bpos pos = iter->pos;
-
-	if ((iter->flags & BTREE_ITER_IS_EXTENTS) &&
-	    !bkey_eq(pos, POS_MAX))
-		pos = bkey_successor(iter, pos);
-	return pos;
-}
-
-static inline bool btree_path_pos_before_node(struct btree_path *path,
-					      struct btree *b)
-{
-	return bpos_lt(path->pos, b->data->min_key);
-}
-
-static inline bool btree_path_pos_after_node(struct btree_path *path,
-					     struct btree *b)
-{
-	return bpos_gt(path->pos, b->key.k.p);
-}
-
-static inline bool btree_path_pos_in_node(struct btree_path *path,
-					  struct btree *b)
-{
-	return path->btree_id == b->c.btree_id &&
-		!btree_path_pos_before_node(path, b) &&
-		!btree_path_pos_after_node(path, b);
-}
-
-/* Btree iterator: */
-
-#ifdef CONFIG_BCACHEFS_DEBUG
-
-static void bch2_btree_path_verify_cached(struct btree_trans *trans,
-					  struct btree_path *path)
-{
-	struct bkey_cached *ck;
-	bool locked = btree_node_locked(path, 0);
-
-	if (!bch2_btree_node_relock(trans, path, 0))
-		return;
-
-	ck = (void *) path->l[0].b;
-	BUG_ON(ck->key.btree_id != path->btree_id ||
-	       !bkey_eq(ck->key.pos, path->pos));
-
-	if (!locked)
-		btree_node_unlock(trans, path, 0);
-}
-
-static void bch2_btree_path_verify_level(struct btree_trans *trans,
-				struct btree_path *path, unsigned level)
-{
-	struct btree_path_level *l;
-	struct btree_node_iter tmp;
-	bool locked;
-	struct bkey_packed *p, *k;
-	struct printbuf buf1 = PRINTBUF;
-	struct printbuf buf2 = PRINTBUF;
-	struct printbuf buf3 = PRINTBUF;
-	const char *msg;
-
-	if (!bch2_debug_check_iterators)
-		return;
-
-	l	= &path->l[level];
-	tmp	= l->iter;
-	locked	= btree_node_locked(path, level);
-
-	if (path->cached) {
-		if (!level)
-			bch2_btree_path_verify_cached(trans, path);
-		return;
-	}
-
-	if (!btree_path_node(path, level))
-		return;
-
-	if (!bch2_btree_node_relock_notrace(trans, path, level))
-		return;
-
-	BUG_ON(!btree_path_pos_in_node(path, l->b));
-
-	bch2_btree_node_iter_verify(&l->iter, l->b);
-
-	/*
-	 * For interior nodes, the iterator will have skipped past deleted keys:
-	 */
-	p = level
-		? bch2_btree_node_iter_prev(&tmp, l->b)
-		: bch2_btree_node_iter_prev_all(&tmp, l->b);
-	k = bch2_btree_node_iter_peek_all(&l->iter, l->b);
-
-	if (p && bkey_iter_pos_cmp(l->b, p, &path->pos) >= 0) {
-		msg = "before";
-		goto err;
-	}
-
-	if (k && bkey_iter_pos_cmp(l->b, k, &path->pos) < 0) {
-		msg = "after";
-		goto err;
-	}
-
-	if (!locked)
-		btree_node_unlock(trans, path, level);
-	return;
-err:
-	bch2_bpos_to_text(&buf1, path->pos);
-
-	if (p) {
-		struct bkey uk = bkey_unpack_key(l->b, p);
-
-		bch2_bkey_to_text(&buf2, &uk);
-	} else {
-		prt_printf(&buf2, "(none)");
-	}
-
-	if (k) {
-		struct bkey uk = bkey_unpack_key(l->b, k);
-
-		bch2_bkey_to_text(&buf3, &uk);
-	} else {
-		prt_printf(&buf3, "(none)");
-	}
-
-	panic("path should be %s key at level %u:\n"
-	      "path pos %s\n"
-	      "prev key %s\n"
-	      "cur  key %s\n",
-	      msg, level, buf1.buf, buf2.buf, buf3.buf);
-}
-
-static void bch2_btree_path_verify(struct btree_trans *trans,
-				   struct btree_path *path)
-{
-	struct bch_fs *c = trans->c;
-	unsigned i;
-
-	EBUG_ON(path->btree_id >= BTREE_ID_NR);
-
-	for (i = 0; i < (!path->cached ? BTREE_MAX_DEPTH : 1); i++) {
-		if (!path->l[i].b) {
-			BUG_ON(!path->cached &&
-			       bch2_btree_id_root(c, path->btree_id)->b->c.level > i);
-			break;
-		}
-
-		bch2_btree_path_verify_level(trans, path, i);
-	}
-
-	bch2_btree_path_verify_locks(path);
-}
-
-void bch2_trans_verify_paths(struct btree_trans *trans)
-{
-	struct btree_path *path;
-	unsigned iter;
-
-	trans_for_each_path(trans, path, iter)
-		bch2_btree_path_verify(trans, path);
-}
-
-static void bch2_btree_iter_verify(struct btree_iter *iter)
-{
-	struct btree_trans *trans = iter->trans;
-
-	BUG_ON(iter->btree_id >= BTREE_ID_NR);
-
-	BUG_ON(!!(iter->flags & BTREE_ITER_CACHED) != btree_iter_path(trans, iter)->cached);
-
-	BUG_ON((iter->flags & BTREE_ITER_IS_EXTENTS) &&
-	       (iter->flags & BTREE_ITER_ALL_SNAPSHOTS));
-
-	BUG_ON(!(iter->flags & __BTREE_ITER_ALL_SNAPSHOTS) &&
-	       (iter->flags & BTREE_ITER_ALL_SNAPSHOTS) &&
-	       !btree_type_has_snapshot_field(iter->btree_id));
-
-	if (iter->update_path)
-		bch2_btree_path_verify(trans, &trans->paths[iter->update_path]);
-	bch2_btree_path_verify(trans, btree_iter_path(trans, iter));
-}
-
-static void bch2_btree_iter_verify_entry_exit(struct btree_iter *iter)
-{
-	BUG_ON((iter->flags & BTREE_ITER_FILTER_SNAPSHOTS) &&
-	       !iter->pos.snapshot);
-
-	BUG_ON(!(iter->flags & BTREE_ITER_ALL_SNAPSHOTS) &&
-	       iter->pos.snapshot != iter->snapshot);
-
-	BUG_ON(bkey_lt(iter->pos, bkey_start_pos(&iter->k)) ||
-	       bkey_gt(iter->pos, iter->k.p));
-}
-
-static int bch2_btree_iter_verify_ret(struct btree_iter *iter, struct bkey_s_c k)
-{
-	struct btree_trans *trans = iter->trans;
-	struct btree_iter copy;
-	struct bkey_s_c prev;
-	int ret = 0;
-
-	if (!bch2_debug_check_iterators)
-		return 0;
-
-	if (!(iter->flags & BTREE_ITER_FILTER_SNAPSHOTS))
-		return 0;
-
-	if (bkey_err(k) || !k.k)
-		return 0;
-
-	BUG_ON(!bch2_snapshot_is_ancestor(trans->c,
-					  iter->snapshot,
-					  k.k->p.snapshot));
-
-	bch2_trans_iter_init(trans, &copy, iter->btree_id, iter->pos,
-			     BTREE_ITER_NOPRESERVE|
-			     BTREE_ITER_ALL_SNAPSHOTS);
-	prev = bch2_btree_iter_prev(&copy);
-	if (!prev.k)
-		goto out;
-
-	ret = bkey_err(prev);
-	if (ret)
-		goto out;
-
-	if (bkey_eq(prev.k->p, k.k->p) &&
-	    bch2_snapshot_is_ancestor(trans->c, iter->snapshot,
-				      prev.k->p.snapshot) > 0) {
-		struct printbuf buf1 = PRINTBUF, buf2 = PRINTBUF;
-
-		bch2_bkey_to_text(&buf1, k.k);
-		bch2_bkey_to_text(&buf2, prev.k);
-
-		panic("iter snap %u\n"
-		      "k    %s\n"
-		      "prev %s\n",
-		      iter->snapshot,
-		      buf1.buf, buf2.buf);
-	}
-out:
-	bch2_trans_iter_exit(trans, &copy);
-	return ret;
-}
-
-void bch2_assert_pos_locked(struct btree_trans *trans, enum btree_id id,
-			    struct bpos pos, bool key_cache)
-{
-	struct btree_path *path;
-	struct trans_for_each_path_inorder_iter iter;
-	struct printbuf buf = PRINTBUF;
-
-	btree_trans_sort_paths(trans);
-
-	trans_for_each_path_inorder(trans, path, iter) {
-		int cmp = cmp_int(path->btree_id, id) ?:
-			cmp_int(path->cached, key_cache);
-
-		if (cmp > 0)
-			break;
-		if (cmp < 0)
-			continue;
-
-		if (!btree_node_locked(path, 0) ||
-		    !path->should_be_locked)
-			continue;
-
-		if (!key_cache) {
-			if (bkey_ge(pos, path->l[0].b->data->min_key) &&
-			    bkey_le(pos, path->l[0].b->key.k.p))
-				return;
-		} else {
-			if (bkey_eq(pos, path->pos))
-				return;
-		}
-	}
-
-	bch2_dump_trans_paths_updates(trans);
-	bch2_bpos_to_text(&buf, pos);
-
-	panic("not locked: %s %s%s\n",
-	      bch2_btree_id_str(id), buf.buf,
-	      key_cache ? " cached" : "");
-}
-
-#else
-
-static inline void bch2_btree_path_verify_level(struct btree_trans *trans,
-						struct btree_path *path, unsigned l) {}
-static inline void bch2_btree_path_verify(struct btree_trans *trans,
-					  struct btree_path *path) {}
-static inline void bch2_btree_iter_verify(struct btree_iter *iter) {}
-static inline void bch2_btree_iter_verify_entry_exit(struct btree_iter *iter) {}
-static inline int bch2_btree_iter_verify_ret(struct btree_iter *iter, struct bkey_s_c k) { return 0; }
-
-#endif
-
-/* Btree path: fixups after btree updates */
-
-static void btree_node_iter_set_set_pos(struct btree_node_iter *iter,
-					struct btree *b,
-					struct bset_tree *t,
-					struct bkey_packed *k)
-{
-	struct btree_node_iter_set *set;
-
-	btree_node_iter_for_each(iter, set)
-		if (set->end == t->end_offset) {
-			set->k = __btree_node_key_to_offset(b, k);
-			bch2_btree_node_iter_sort(iter, b);
-			return;
-		}
-
-	bch2_btree_node_iter_push(iter, b, k, btree_bkey_last(b, t));
-}
-
-static void __bch2_btree_path_fix_key_modified(struct btree_path *path,
-					       struct btree *b,
-					       struct bkey_packed *where)
-{
-	struct btree_path_level *l = &path->l[b->c.level];
-
-	if (where != bch2_btree_node_iter_peek_all(&l->iter, l->b))
-		return;
-
-	if (bkey_iter_pos_cmp(l->b, where, &path->pos) < 0)
-		bch2_btree_node_iter_advance(&l->iter, l->b);
-}
-
-void bch2_btree_path_fix_key_modified(struct btree_trans *trans,
-				      struct btree *b,
-				      struct bkey_packed *where)
-{
-	struct btree_path *path;
-	unsigned i;
-
-	trans_for_each_path_with_node(trans, b, path, i) {
-		__bch2_btree_path_fix_key_modified(path, b, where);
-		bch2_btree_path_verify_level(trans, path, b->c.level);
-	}
-}
-
-static void __bch2_btree_node_iter_fix(struct btree_path *path,
-				       struct btree *b,
-				       struct btree_node_iter *node_iter,
-				       struct bset_tree *t,
-				       struct bkey_packed *where,
-				       unsigned clobber_u64s,
-				       unsigned new_u64s)
-{
-	const struct bkey_packed *end = btree_bkey_last(b, t);
-	struct btree_node_iter_set *set;
-	unsigned offset = __btree_node_key_to_offset(b, where);
-	int shift = new_u64s - clobber_u64s;
-	unsigned old_end = t->end_offset - shift;
-	unsigned orig_iter_pos = node_iter->data[0].k;
-	bool iter_current_key_modified =
-		orig_iter_pos >= offset &&
-		orig_iter_pos <= offset + clobber_u64s;
-
-	btree_node_iter_for_each(node_iter, set)
-		if (set->end == old_end)
-			goto found;
-
-	/* didn't find the bset in the iterator - might have to readd it: */
-	if (new_u64s &&
-	    bkey_iter_pos_cmp(b, where, &path->pos) >= 0) {
-		bch2_btree_node_iter_push(node_iter, b, where, end);
-		goto fixup_done;
-	} else {
-		/* Iterator is after key that changed */
-		return;
-	}
-found:
-	set->end = t->end_offset;
-
-	/* Iterator hasn't gotten to the key that changed yet: */
-	if (set->k < offset)
-		return;
-
-	if (new_u64s &&
-	    bkey_iter_pos_cmp(b, where, &path->pos) >= 0) {
-		set->k = offset;
-	} else if (set->k < offset + clobber_u64s) {
-		set->k = offset + new_u64s;
-		if (set->k == set->end)
-			bch2_btree_node_iter_set_drop(node_iter, set);
-	} else {
-		/* Iterator is after key that changed */
-		set->k = (int) set->k + shift;
-		return;
-	}
-
-	bch2_btree_node_iter_sort(node_iter, b);
-fixup_done:
-	if (node_iter->data[0].k != orig_iter_pos)
-		iter_current_key_modified = true;
-
-	/*
-	 * When a new key is added, and the node iterator now points to that
-	 * key, the iterator might have skipped past deleted keys that should
-	 * come after the key the iterator now points to. We have to rewind to
-	 * before those deleted keys - otherwise
-	 * bch2_btree_node_iter_prev_all() breaks:
-	 */
-	if (!bch2_btree_node_iter_end(node_iter) &&
-	    iter_current_key_modified &&
-	    b->c.level) {
-		struct bkey_packed *k, *k2, *p;
-
-		k = bch2_btree_node_iter_peek_all(node_iter, b);
-
-		for_each_bset(b, t) {
-			bool set_pos = false;
-
-			if (node_iter->data[0].end == t->end_offset)
-				continue;
-
-			k2 = bch2_btree_node_iter_bset_pos(node_iter, b, t);
-
-			while ((p = bch2_bkey_prev_all(b, t, k2)) &&
-			       bkey_iter_cmp(b, k, p) < 0) {
-				k2 = p;
-				set_pos = true;
-			}
-
-			if (set_pos)
-				btree_node_iter_set_set_pos(node_iter,
-							    b, t, k2);
-		}
-	}
-}
-
-void bch2_btree_node_iter_fix(struct btree_trans *trans,
-			      struct btree_path *path,
-			      struct btree *b,
-			      struct btree_node_iter *node_iter,
-			      struct bkey_packed *where,
-			      unsigned clobber_u64s,
-			      unsigned new_u64s)
-{
-	struct bset_tree *t = bch2_bkey_to_bset_inlined(b, where);
-	struct btree_path *linked;
-	unsigned i;
-
-	if (node_iter != &path->l[b->c.level].iter) {
-		__bch2_btree_node_iter_fix(path, b, node_iter, t,
-					   where, clobber_u64s, new_u64s);
-
-		if (bch2_debug_check_iterators)
-			bch2_btree_node_iter_verify(node_iter, b);
-	}
-
-	trans_for_each_path_with_node(trans, b, linked, i) {
-		__bch2_btree_node_iter_fix(linked, b,
-					   &linked->l[b->c.level].iter, t,
-					   where, clobber_u64s, new_u64s);
-		bch2_btree_path_verify_level(trans, linked, b->c.level);
-	}
-}
-
-/* Btree path level: pointer to a particular btree node and node iter */
-
-static inline struct bkey_s_c __btree_iter_unpack(struct bch_fs *c,
-						  struct btree_path_level *l,
-						  struct bkey *u,
-						  struct bkey_packed *k)
-{
-	if (unlikely(!k)) {
-		/*
-		 * signal to bch2_btree_iter_peek_slot() that we're currently at
-		 * a hole
-		 */
-		u->type = KEY_TYPE_deleted;
-		return bkey_s_c_null;
-	}
-
-	return bkey_disassemble(l->b, k, u);
-}
-
-static inline struct bkey_s_c btree_path_level_peek_all(struct bch_fs *c,
-							struct btree_path_level *l,
-							struct bkey *u)
-{
-	return __btree_iter_unpack(c, l, u,
-			bch2_btree_node_iter_peek_all(&l->iter, l->b));
-}
-
-static inline struct bkey_s_c btree_path_level_peek(struct btree_trans *trans,
-						    struct btree_path *path,
-						    struct btree_path_level *l,
-						    struct bkey *u)
-{
-	struct bkey_s_c k = __btree_iter_unpack(trans->c, l, u,
-			bch2_btree_node_iter_peek(&l->iter, l->b));
-
-	path->pos = k.k ? k.k->p : l->b->key.k.p;
-	trans->paths_sorted = false;
-	bch2_btree_path_verify_level(trans, path, l - path->l);
-	return k;
-}
-
-static inline struct bkey_s_c btree_path_level_prev(struct btree_trans *trans,
-						    struct btree_path *path,
-						    struct btree_path_level *l,
-						    struct bkey *u)
-{
-	struct bkey_s_c k = __btree_iter_unpack(trans->c, l, u,
-			bch2_btree_node_iter_prev(&l->iter, l->b));
-
-	path->pos = k.k ? k.k->p : l->b->data->min_key;
-	trans->paths_sorted = false;
-	bch2_btree_path_verify_level(trans, path, l - path->l);
-	return k;
-}
-
-static inline bool btree_path_advance_to_pos(struct btree_path *path,
-					     struct btree_path_level *l,
-					     int max_advance)
-{
-	struct bkey_packed *k;
-	int nr_advanced = 0;
-
-	while ((k = bch2_btree_node_iter_peek_all(&l->iter, l->b)) &&
-	       bkey_iter_pos_cmp(l->b, k, &path->pos) < 0) {
-		if (max_advance > 0 && nr_advanced >= max_advance)
-			return false;
-
-		bch2_btree_node_iter_advance(&l->iter, l->b);
-		nr_advanced++;
-	}
-
-	return true;
-}
-
-static inline void __btree_path_level_init(struct btree_path *path,
-					   unsigned level)
-{
-	struct btree_path_level *l = &path->l[level];
-
-	bch2_btree_node_iter_init(&l->iter, l->b, &path->pos);
-
-	/*
-	 * Iterators to interior nodes should always be pointed at the first non
-	 * whiteout:
-	 */
-	if (level)
-		bch2_btree_node_iter_peek(&l->iter, l->b);
-}
-
-void bch2_btree_path_level_init(struct btree_trans *trans,
-				struct btree_path *path,
-				struct btree *b)
-{
-	BUG_ON(path->cached);
-
-	EBUG_ON(!btree_path_pos_in_node(path, b));
-
-	path->l[b->c.level].lock_seq = six_lock_seq(&b->c.lock);
-	path->l[b->c.level].b = b;
-	__btree_path_level_init(path, b->c.level);
-}
-
-/* Btree path: fixups after btree node updates: */
-
-static void bch2_trans_revalidate_updates_in_node(struct btree_trans *trans, struct btree *b)
-{
-	struct bch_fs *c = trans->c;
-
-	trans_for_each_update(trans, i)
-		if (!i->cached &&
-		    i->level	== b->c.level &&
-		    i->btree_id	== b->c.btree_id &&
-		    bpos_cmp(i->k->k.p, b->data->min_key) >= 0 &&
-		    bpos_cmp(i->k->k.p, b->data->max_key) <= 0) {
-			i->old_v = bch2_btree_path_peek_slot(trans->paths + i->path, &i->old_k).v;
-
-			if (unlikely(trans->journal_replay_not_finished)) {
-				struct bkey_i *j_k =
-					bch2_journal_keys_peek_slot(c, i->btree_id, i->level,
-								    i->k->k.p);
-
-				if (j_k) {
-					i->old_k = j_k->k;
-					i->old_v = &j_k->v;
-				}
-			}
-		}
-}
-
-/*
- * A btree node is being replaced - update the iterator to point to the new
- * node:
- */
-void bch2_trans_node_add(struct btree_trans *trans,
-			 struct btree_path *path,
-			 struct btree *b)
-{
-	struct btree_path *prev;
-
-	BUG_ON(!btree_path_pos_in_node(path, b));
-
-	while ((prev = prev_btree_path(trans, path)) &&
-	       btree_path_pos_in_node(prev, b))
-		path = prev;
-
-	for (;
-	     path && btree_path_pos_in_node(path, b);
-	     path = next_btree_path(trans, path))
-		if (path->uptodate == BTREE_ITER_UPTODATE && !path->cached) {
-			enum btree_node_locked_type t =
-				btree_lock_want(path, b->c.level);
-
-			if (t != BTREE_NODE_UNLOCKED) {
-				btree_node_unlock(trans, path, b->c.level);
-				six_lock_increment(&b->c.lock, (enum six_lock_type) t);
-				mark_btree_node_locked(trans, path, b->c.level, t);
-			}
-
-			bch2_btree_path_level_init(trans, path, b);
-		}
-
-	bch2_trans_revalidate_updates_in_node(trans, b);
-}
-
-/*
- * A btree node has been modified in such a way as to invalidate iterators - fix
- * them:
- */
-void bch2_trans_node_reinit_iter(struct btree_trans *trans, struct btree *b)
-{
-	struct btree_path *path;
-	unsigned i;
-
-	trans_for_each_path_with_node(trans, b, path, i)
-		__btree_path_level_init(path, b->c.level);
-
-	bch2_trans_revalidate_updates_in_node(trans, b);
-}
-
-/* Btree path: traverse, set_pos: */
-
-static inline int btree_path_lock_root(struct btree_trans *trans,
-				       struct btree_path *path,
-				       unsigned depth_want,
-				       unsigned long trace_ip)
-{
-	struct bch_fs *c = trans->c;
-	struct btree *b, **rootp = &bch2_btree_id_root(c, path->btree_id)->b;
-	enum six_lock_type lock_type;
-	unsigned i;
-	int ret;
-
-	EBUG_ON(path->nodes_locked);
-
-	while (1) {
-		b = READ_ONCE(*rootp);
-		path->level = READ_ONCE(b->c.level);
-
-		if (unlikely(path->level < depth_want)) {
-			/*
-			 * the root is at a lower depth than the depth we want:
-			 * got to the end of the btree, or we're walking nodes
-			 * greater than some depth and there are no nodes >=
-			 * that depth
-			 */
-			path->level = depth_want;
-			for (i = path->level; i < BTREE_MAX_DEPTH; i++)
-				path->l[i].b = NULL;
-			return 1;
-		}
-
-		lock_type = __btree_lock_want(path, path->level);
-		ret = btree_node_lock(trans, path, &b->c,
-				      path->level, lock_type, trace_ip);
-		if (unlikely(ret)) {
-			if (bch2_err_matches(ret, BCH_ERR_lock_fail_root_changed))
-				continue;
-			if (bch2_err_matches(ret, BCH_ERR_transaction_restart))
-				return ret;
-			BUG();
-		}
-
-		if (likely(b == READ_ONCE(*rootp) &&
-			   b->c.level == path->level &&
-			   !race_fault())) {
-			for (i = 0; i < path->level; i++)
-				path->l[i].b = ERR_PTR(-BCH_ERR_no_btree_node_lock_root);
-			path->l[path->level].b = b;
-			for (i = path->level + 1; i < BTREE_MAX_DEPTH; i++)
-				path->l[i].b = NULL;
-
-			mark_btree_node_locked(trans, path, path->level,
-					       (enum btree_node_locked_type) lock_type);
-			bch2_btree_path_level_init(trans, path, b);
-			return 0;
-		}
-
-		six_unlock_type(&b->c.lock, lock_type);
-	}
-}
-
-noinline
-static int btree_path_prefetch(struct btree_trans *trans, struct btree_path *path)
-{
-	struct bch_fs *c = trans->c;
-	struct btree_path_level *l = path_l(path);
-	struct btree_node_iter node_iter = l->iter;
-	struct bkey_packed *k;
-	struct bkey_buf tmp;
-	unsigned nr = test_bit(BCH_FS_started, &c->flags)
-		? (path->level > 1 ? 0 :  2)
-		: (path->level > 1 ? 1 : 16);
-	bool was_locked = btree_node_locked(path, path->level);
-	int ret = 0;
-
-	bch2_bkey_buf_init(&tmp);
-
-	while (nr-- && !ret) {
-		if (!bch2_btree_node_relock(trans, path, path->level))
-			break;
-
-		bch2_btree_node_iter_advance(&node_iter, l->b);
-		k = bch2_btree_node_iter_peek(&node_iter, l->b);
-		if (!k)
-			break;
-
-		bch2_bkey_buf_unpack(&tmp, c, l->b, k);
-		ret = bch2_btree_node_prefetch(trans, path, tmp.k, path->btree_id,
-					       path->level - 1);
-	}
-
-	if (!was_locked)
-		btree_node_unlock(trans, path, path->level);
-
-	bch2_bkey_buf_exit(&tmp, c);
-	return ret;
-}
-
-static int btree_path_prefetch_j(struct btree_trans *trans, struct btree_path *path,
-				 struct btree_and_journal_iter *jiter)
-{
-	struct bch_fs *c = trans->c;
-	struct bkey_s_c k;
-	struct bkey_buf tmp;
-	unsigned nr = test_bit(BCH_FS_started, &c->flags)
-		? (path->level > 1 ? 0 :  2)
-		: (path->level > 1 ? 1 : 16);
-	bool was_locked = btree_node_locked(path, path->level);
-	int ret = 0;
-
-	bch2_bkey_buf_init(&tmp);
-
-	while (nr-- && !ret) {
-		if (!bch2_btree_node_relock(trans, path, path->level))
-			break;
-
-		bch2_btree_and_journal_iter_advance(jiter);
-		k = bch2_btree_and_journal_iter_peek(jiter);
-		if (!k.k)
-			break;
-
-		bch2_bkey_buf_reassemble(&tmp, c, k);
-		ret = bch2_btree_node_prefetch(trans, path, tmp.k, path->btree_id,
-					       path->level - 1);
-	}
-
-	if (!was_locked)
-		btree_node_unlock(trans, path, path->level);
-
-	bch2_bkey_buf_exit(&tmp, c);
-	return ret;
-}
-
-static noinline void btree_node_mem_ptr_set(struct btree_trans *trans,
-					    struct btree_path *path,
-					    unsigned plevel, struct btree *b)
-{
-	struct btree_path_level *l = &path->l[plevel];
-	bool locked = btree_node_locked(path, plevel);
-	struct bkey_packed *k;
-	struct bch_btree_ptr_v2 *bp;
-
-	if (!bch2_btree_node_relock(trans, path, plevel))
-		return;
-
-	k = bch2_btree_node_iter_peek_all(&l->iter, l->b);
-	BUG_ON(k->type != KEY_TYPE_btree_ptr_v2);
-
-	bp = (void *) bkeyp_val(&l->b->format, k);
-	bp->mem_ptr = (unsigned long)b;
-
-	if (!locked)
-		btree_node_unlock(trans, path, plevel);
-}
-
-static noinline int btree_node_iter_and_journal_peek(struct btree_trans *trans,
-						     struct btree_path *path,
-						     unsigned flags,
-						     struct bkey_buf *out)
-{
-	struct bch_fs *c = trans->c;
-	struct btree_path_level *l = path_l(path);
-	struct btree_and_journal_iter jiter;
-	struct bkey_s_c k;
-	int ret = 0;
-
-	__bch2_btree_and_journal_iter_init_node_iter(&jiter, c, l->b, l->iter, path->pos);
-
-	k = bch2_btree_and_journal_iter_peek(&jiter);
-
-	bch2_bkey_buf_reassemble(out, c, k);
-
-	if ((flags & BTREE_ITER_PREFETCH) &&
-	    c->opts.btree_node_prefetch)
-		ret = btree_path_prefetch_j(trans, path, &jiter);
-
-	bch2_btree_and_journal_iter_exit(&jiter);
-	return ret;
-}
-
-static __always_inline int btree_path_down(struct btree_trans *trans,
-					   struct btree_path *path,
-					   unsigned flags,
-					   unsigned long trace_ip)
-{
-	struct bch_fs *c = trans->c;
-	struct btree_path_level *l = path_l(path);
-	struct btree *b;
-	unsigned level = path->level - 1;
-	enum six_lock_type lock_type = __btree_lock_want(path, level);
-	struct bkey_buf tmp;
-	int ret;
-
-	EBUG_ON(!btree_node_locked(path, path->level));
-
-	bch2_bkey_buf_init(&tmp);
-
-	if (unlikely(trans->journal_replay_not_finished)) {
-		ret = btree_node_iter_and_journal_peek(trans, path, flags, &tmp);
-		if (ret)
-			goto err;
-	} else {
-		bch2_bkey_buf_unpack(&tmp, c, l->b,
-				 bch2_btree_node_iter_peek(&l->iter, l->b));
-
-		if ((flags & BTREE_ITER_PREFETCH) &&
-		    c->opts.btree_node_prefetch) {
-			ret = btree_path_prefetch(trans, path);
-			if (ret)
-				goto err;
-		}
-	}
-
-	b = bch2_btree_node_get(trans, path, tmp.k, level, lock_type, trace_ip);
-	ret = PTR_ERR_OR_ZERO(b);
-	if (unlikely(ret))
-		goto err;
-
-	if (likely(!trans->journal_replay_not_finished &&
-		   tmp.k->k.type == KEY_TYPE_btree_ptr_v2) &&
-	    unlikely(b != btree_node_mem_ptr(tmp.k)))
-		btree_node_mem_ptr_set(trans, path, level + 1, b);
-
-	if (btree_node_read_locked(path, level + 1))
-		btree_node_unlock(trans, path, level + 1);
-
-	mark_btree_node_locked(trans, path, level,
-			       (enum btree_node_locked_type) lock_type);
-	path->level = level;
-	bch2_btree_path_level_init(trans, path, b);
-
-	bch2_btree_path_verify_locks(path);
-err:
-	bch2_bkey_buf_exit(&tmp, c);
-	return ret;
-}
-
-
-static int bch2_btree_path_traverse_all(struct btree_trans *trans)
-{
-	struct bch_fs *c = trans->c;
-	struct btree_path *path;
-	unsigned long trace_ip = _RET_IP_;
-	unsigned i;
-	int ret = 0;
-
-	if (trans->in_traverse_all)
-		return -BCH_ERR_transaction_restart_in_traverse_all;
-
-	trans->in_traverse_all = true;
-retry_all:
-	trans->restarted = 0;
-	trans->last_restarted_ip = 0;
-
-	trans_for_each_path(trans, path, i)
-		path->should_be_locked = false;
-
-	btree_trans_sort_paths(trans);
-
-	bch2_trans_unlock(trans);
-	cond_resched();
-
-	if (unlikely(trans->memory_allocation_failure)) {
-		struct closure cl;
-
-		closure_init_stack(&cl);
-
-		do {
-			ret = bch2_btree_cache_cannibalize_lock(trans, &cl);
-			closure_sync(&cl);
-		} while (ret);
-	}
-
-	/* Now, redo traversals in correct order: */
-	i = 0;
-	while (i < trans->nr_sorted) {
-		btree_path_idx_t idx = trans->sorted[i];
-
-		/*
-		 * Traversing a path can cause another path to be added at about
-		 * the same position:
-		 */
-		if (trans->paths[idx].uptodate) {
-			__btree_path_get(&trans->paths[idx], false);
-			ret = bch2_btree_path_traverse_one(trans, idx, 0, _THIS_IP_);
-			__btree_path_put(&trans->paths[idx], false);
-
-			if (bch2_err_matches(ret, BCH_ERR_transaction_restart) ||
-			    bch2_err_matches(ret, ENOMEM))
-				goto retry_all;
-			if (ret)
-				goto err;
-		} else {
-			i++;
-		}
-	}
-
-	/*
-	 * We used to assert that all paths had been traversed here
-	 * (path->uptodate < BTREE_ITER_NEED_TRAVERSE); however, since
-	 * path->should_be_locked is not set yet, we might have unlocked and
-	 * then failed to relock a path - that's fine.
-	 */
-err:
-	bch2_btree_cache_cannibalize_unlock(trans);
-
-	trans->in_traverse_all = false;
-
-	trace_and_count(c, trans_traverse_all, trans, trace_ip);
-	return ret;
-}
-
-static inline bool btree_path_check_pos_in_node(struct btree_path *path,
-						unsigned l, int check_pos)
-{
-	if (check_pos < 0 && btree_path_pos_before_node(path, path->l[l].b))
-		return false;
-	if (check_pos > 0 && btree_path_pos_after_node(path, path->l[l].b))
-		return false;
-	return true;
-}
-
-static inline bool btree_path_good_node(struct btree_trans *trans,
-					struct btree_path *path,
-					unsigned l, int check_pos)
-{
-	return is_btree_node(path, l) &&
-		bch2_btree_node_relock(trans, path, l) &&
-		btree_path_check_pos_in_node(path, l, check_pos);
-}
-
-static void btree_path_set_level_down(struct btree_trans *trans,
-				      struct btree_path *path,
-				      unsigned new_level)
-{
-	unsigned l;
-
-	path->level = new_level;
-
-	for (l = path->level + 1; l < BTREE_MAX_DEPTH; l++)
-		if (btree_lock_want(path, l) == BTREE_NODE_UNLOCKED)
-			btree_node_unlock(trans, path, l);
-
-	btree_path_set_dirty(path, BTREE_ITER_NEED_TRAVERSE);
-	bch2_btree_path_verify(trans, path);
-}
-
-static noinline unsigned __btree_path_up_until_good_node(struct btree_trans *trans,
-							 struct btree_path *path,
-							 int check_pos)
-{
-	unsigned i, l = path->level;
-again:
-	while (btree_path_node(path, l) &&
-	       !btree_path_good_node(trans, path, l, check_pos))
-		__btree_path_set_level_up(trans, path, l++);
-
-	/* If we need intent locks, take them too: */
-	for (i = l + 1;
-	     i < path->locks_want && btree_path_node(path, i);
-	     i++)
-		if (!bch2_btree_node_relock(trans, path, i)) {
-			while (l <= i)
-				__btree_path_set_level_up(trans, path, l++);
-			goto again;
-		}
-
-	return l;
-}
-
-static inline unsigned btree_path_up_until_good_node(struct btree_trans *trans,
-						     struct btree_path *path,
-						     int check_pos)
-{
-	return likely(btree_node_locked(path, path->level) &&
-		      btree_path_check_pos_in_node(path, path->level, check_pos))
-		? path->level
-		: __btree_path_up_until_good_node(trans, path, check_pos);
-}
-
-/*
- * This is the main state machine for walking down the btree - walks down to a
- * specified depth
- *
- * Returns 0 on success, -EIO on error (error reading in a btree node).
- *
- * On error, caller (peek_node()/peek_key()) must return NULL; the error is
- * stashed in the iterator and returned from bch2_trans_exit().
- */
-int bch2_btree_path_traverse_one(struct btree_trans *trans,
-				 btree_path_idx_t path_idx,
-				 unsigned flags,
-				 unsigned long trace_ip)
-{
-	struct btree_path *path = &trans->paths[path_idx];
-	unsigned depth_want = path->level;
-	int ret = -((int) trans->restarted);
-
-	if (unlikely(ret))
-		goto out;
-
-	if (unlikely(!trans->srcu_held))
-		bch2_trans_srcu_lock(trans);
-
-	/*
-	 * Ensure we obey path->should_be_locked: if it's set, we can't unlock
-	 * and re-traverse the path without a transaction restart:
-	 */
-	if (path->should_be_locked) {
-		ret = bch2_btree_path_relock(trans, path, trace_ip);
-		goto out;
-	}
-
-	if (path->cached) {
-		ret = bch2_btree_path_traverse_cached(trans, path, flags);
-		goto out;
-	}
-
-	path = &trans->paths[path_idx];
-
-	if (unlikely(path->level >= BTREE_MAX_DEPTH))
-		goto out;
-
-	path->level = btree_path_up_until_good_node(trans, path, 0);
-
-	EBUG_ON(btree_path_node(path, path->level) &&
-		!btree_node_locked(path, path->level));
-
-	/*
-	 * Note: path->nodes[path->level] may be temporarily NULL here - that
-	 * would indicate to other code that we got to the end of the btree,
-	 * here it indicates that relocking the root failed - it's critical that
-	 * btree_path_lock_root() comes next and that it can't fail
-	 */
-	while (path->level > depth_want) {
-		ret = btree_path_node(path, path->level)
-			? btree_path_down(trans, path, flags, trace_ip)
-			: btree_path_lock_root(trans, path, depth_want, trace_ip);
-		if (unlikely(ret)) {
-			if (ret == 1) {
-				/*
-				 * No nodes at this level - got to the end of
-				 * the btree:
-				 */
-				ret = 0;
-				goto out;
-			}
-
-			__bch2_btree_path_unlock(trans, path);
-			path->level = depth_want;
-			path->l[path->level].b = ERR_PTR(ret);
-			goto out;
-		}
-	}
-
-	path->uptodate = BTREE_ITER_UPTODATE;
-out:
-	if (bch2_err_matches(ret, BCH_ERR_transaction_restart) != !!trans->restarted)
-		panic("ret %s (%i) trans->restarted %s (%i)\n",
-		      bch2_err_str(ret), ret,
-		      bch2_err_str(trans->restarted), trans->restarted);
-	bch2_btree_path_verify(trans, path);
-	return ret;
-}
-
-static inline void btree_path_copy(struct btree_trans *trans, struct btree_path *dst,
-			    struct btree_path *src)
-{
-	unsigned i, offset = offsetof(struct btree_path, pos);
-
-	memcpy((void *) dst + offset,
-	       (void *) src + offset,
-	       sizeof(struct btree_path) - offset);
-
-	for (i = 0; i < BTREE_MAX_DEPTH; i++) {
-		unsigned t = btree_node_locked_type(dst, i);
-
-		if (t != BTREE_NODE_UNLOCKED)
-			six_lock_increment(&dst->l[i].b->c.lock, t);
-	}
-}
-
-static btree_path_idx_t btree_path_clone(struct btree_trans *trans, btree_path_idx_t src,
-					 bool intent)
-{
-	btree_path_idx_t new = btree_path_alloc(trans, src);
-	btree_path_copy(trans, trans->paths + new, trans->paths + src);
-	__btree_path_get(trans->paths + new, intent);
-	return new;
-}
-
-__flatten
-btree_path_idx_t __bch2_btree_path_make_mut(struct btree_trans *trans,
-			btree_path_idx_t path, bool intent, unsigned long ip)
-{
-	__btree_path_put(trans->paths + path, intent);
-	path = btree_path_clone(trans, path, intent);
-	trans->paths[path].preserve = false;
-	return path;
-}
-
-btree_path_idx_t __must_check
-__bch2_btree_path_set_pos(struct btree_trans *trans,
-			  btree_path_idx_t path_idx, struct bpos new_pos,
-			  bool intent, unsigned long ip)
-{
-	int cmp = bpos_cmp(new_pos, trans->paths[path_idx].pos);
-
-	bch2_trans_verify_not_in_restart(trans);
-	EBUG_ON(!trans->paths[path_idx].ref);
-
-	path_idx = bch2_btree_path_make_mut(trans, path_idx, intent, ip);
-
-	struct btree_path *path = trans->paths + path_idx;
-	path->pos		= new_pos;
-	trans->paths_sorted	= false;
-
-	if (unlikely(path->cached)) {
-		btree_node_unlock(trans, path, 0);
-		path->l[0].b = ERR_PTR(-BCH_ERR_no_btree_node_up);
-		btree_path_set_dirty(path, BTREE_ITER_NEED_TRAVERSE);
-		goto out;
-	}
-
-	unsigned level = btree_path_up_until_good_node(trans, path, cmp);
-
-	if (btree_path_node(path, level)) {
-		struct btree_path_level *l = &path->l[level];
-
-		BUG_ON(!btree_node_locked(path, level));
-		/*
-		 * We might have to skip over many keys, or just a few: try
-		 * advancing the node iterator, and if we have to skip over too
-		 * many keys just reinit it (or if we're rewinding, since that
-		 * is expensive).
-		 */
-		if (cmp < 0 ||
-		    !btree_path_advance_to_pos(path, l, 8))
-			bch2_btree_node_iter_init(&l->iter, l->b, &path->pos);
-
-		/*
-		 * Iterators to interior nodes should always be pointed at the first non
-		 * whiteout:
-		 */
-		if (unlikely(level))
-			bch2_btree_node_iter_peek(&l->iter, l->b);
-	}
-
-	if (unlikely(level != path->level)) {
-		btree_path_set_dirty(path, BTREE_ITER_NEED_TRAVERSE);
-		__bch2_btree_path_unlock(trans, path);
-	}
-out:
-	bch2_btree_path_verify(trans, path);
-	return path_idx;
-}
-
-/* Btree path: main interface: */
-
-static struct btree_path *have_path_at_pos(struct btree_trans *trans, struct btree_path *path)
-{
-	struct btree_path *sib;
-
-	sib = prev_btree_path(trans, path);
-	if (sib && !btree_path_cmp(sib, path))
-		return sib;
-
-	sib = next_btree_path(trans, path);
-	if (sib && !btree_path_cmp(sib, path))
-		return sib;
-
-	return NULL;
-}
-
-static struct btree_path *have_node_at_pos(struct btree_trans *trans, struct btree_path *path)
-{
-	struct btree_path *sib;
-
-	sib = prev_btree_path(trans, path);
-	if (sib && sib->level == path->level && path_l(sib)->b == path_l(path)->b)
-		return sib;
-
-	sib = next_btree_path(trans, path);
-	if (sib && sib->level == path->level && path_l(sib)->b == path_l(path)->b)
-		return sib;
-
-	return NULL;
-}
-
-static inline void __bch2_path_free(struct btree_trans *trans, btree_path_idx_t path)
-{
-	__bch2_btree_path_unlock(trans, trans->paths + path);
-	btree_path_list_remove(trans, trans->paths + path);
-	__clear_bit(path, trans->paths_allocated);
-}
-
-void bch2_path_put(struct btree_trans *trans, btree_path_idx_t path_idx, bool intent)
-{
-	struct btree_path *path = trans->paths + path_idx, *dup;
-
-	if (!__btree_path_put(path, intent))
-		return;
-
-	dup = path->preserve
-		? have_path_at_pos(trans, path)
-		: have_node_at_pos(trans, path);
-
-	if (!dup && !(!path->preserve && !is_btree_node(path, path->level)))
-		return;
-
-	if (path->should_be_locked &&
-	    !trans->restarted &&
-	    (!dup || !bch2_btree_path_relock_norestart(trans, dup, _THIS_IP_)))
-		return;
-
-	if (dup) {
-		dup->preserve		|= path->preserve;
-		dup->should_be_locked	|= path->should_be_locked;
-	}
-
-	__bch2_path_free(trans, path_idx);
-}
-
-static void bch2_path_put_nokeep(struct btree_trans *trans, btree_path_idx_t path,
-				 bool intent)
-{
-	if (!__btree_path_put(trans->paths + path, intent))
-		return;
-
-	__bch2_path_free(trans, path);
-}
-
-void __noreturn bch2_trans_restart_error(struct btree_trans *trans, u32 restart_count)
-{
-	panic("trans->restart_count %u, should be %u, last restarted by %pS\n",
-	      trans->restart_count, restart_count,
-	      (void *) trans->last_begin_ip);
-}
-
-void __noreturn bch2_trans_in_restart_error(struct btree_trans *trans)
-{
-	panic("in transaction restart: %s, last restarted by %pS\n",
-	      bch2_err_str(trans->restarted),
-	      (void *) trans->last_restarted_ip);
-}
-
-noinline __cold
-void bch2_trans_updates_to_text(struct printbuf *buf, struct btree_trans *trans)
-{
-	prt_printf(buf, "transaction updates for %s journal seq %llu",
-	       trans->fn, trans->journal_res.seq);
-	prt_newline(buf);
-	printbuf_indent_add(buf, 2);
-
-	trans_for_each_update(trans, i) {
-		struct bkey_s_c old = { &i->old_k, i->old_v };
-
-		prt_printf(buf, "update: btree=%s cached=%u %pS",
-		       bch2_btree_id_str(i->btree_id),
-		       i->cached,
-		       (void *) i->ip_allocated);
-		prt_newline(buf);
-
-		prt_printf(buf, "  old ");
-		bch2_bkey_val_to_text(buf, trans->c, old);
-		prt_newline(buf);
-
-		prt_printf(buf, "  new ");
-		bch2_bkey_val_to_text(buf, trans->c, bkey_i_to_s_c(i->k));
-		prt_newline(buf);
-	}
-
-	for (struct jset_entry *e = trans->journal_entries;
-	     e != btree_trans_journal_entries_top(trans);
-	     e = vstruct_next(e))
-		bch2_journal_entry_to_text(buf, trans->c, e);
-
-	printbuf_indent_sub(buf, 2);
-}
-
-noinline __cold
-void bch2_dump_trans_updates(struct btree_trans *trans)
-{
-	struct printbuf buf = PRINTBUF;
-
-	bch2_trans_updates_to_text(&buf, trans);
-	bch2_print_string_as_lines(KERN_ERR, buf.buf);
-	printbuf_exit(&buf);
-}
-
-static void bch2_btree_path_to_text(struct printbuf *out, struct btree_trans *trans, btree_path_idx_t path_idx)
-{
-	struct btree_path *path = trans->paths + path_idx;
-
-	prt_printf(out, "path: idx %2u ref %u:%u %c %c btree=%s l=%u pos ",
-		   path_idx, path->ref, path->intent_ref,
-		   path->preserve ? 'P' : ' ',
-		   path->should_be_locked ? 'S' : ' ',
-		   bch2_btree_id_str(path->btree_id),
-		   path->level);
-	bch2_bpos_to_text(out, path->pos);
-
-	prt_printf(out, " locks %u", path->nodes_locked);
-#ifdef TRACK_PATH_ALLOCATED
-	prt_printf(out, " %pS", (void *) path->ip_allocated);
-#endif
-	prt_newline(out);
-}
-
-static noinline __cold
-void __bch2_trans_paths_to_text(struct printbuf *out, struct btree_trans *trans,
-				bool nosort)
-{
-	struct trans_for_each_path_inorder_iter iter;
-
-	if (!nosort)
-		btree_trans_sort_paths(trans);
-
-	trans_for_each_path_idx_inorder(trans, iter)
-		bch2_btree_path_to_text(out, trans, iter.path_idx);
-}
-
-noinline __cold
-void bch2_trans_paths_to_text(struct printbuf *out, struct btree_trans *trans)
-{
-	__bch2_trans_paths_to_text(out, trans, false);
-}
-
-static noinline __cold
-void __bch2_dump_trans_paths_updates(struct btree_trans *trans, bool nosort)
-{
-	struct printbuf buf = PRINTBUF;
-
-	__bch2_trans_paths_to_text(&buf, trans, nosort);
-	bch2_trans_updates_to_text(&buf, trans);
-
-	bch2_print_string_as_lines(KERN_ERR, buf.buf);
-	printbuf_exit(&buf);
-}
-
-noinline __cold
-void bch2_dump_trans_paths_updates(struct btree_trans *trans)
-{
-	__bch2_dump_trans_paths_updates(trans, false);
-}
-
-noinline __cold
-static void bch2_trans_update_max_paths(struct btree_trans *trans)
-{
-	struct btree_transaction_stats *s = btree_trans_stats(trans);
-	struct printbuf buf = PRINTBUF;
-	size_t nr = bitmap_weight(trans->paths_allocated, trans->nr_paths);
-
-	bch2_trans_paths_to_text(&buf, trans);
-
-	if (!buf.allocation_failure) {
-		mutex_lock(&s->lock);
-		if (nr > s->nr_max_paths) {
-			s->nr_max_paths = nr;
-			swap(s->max_paths_text, buf.buf);
-		}
-		mutex_unlock(&s->lock);
-	}
-
-	printbuf_exit(&buf);
-
-	trans->nr_paths_max = nr;
-}
-
-noinline __cold
-int __bch2_btree_trans_too_many_iters(struct btree_trans *trans)
-{
-	if (trace_trans_restart_too_many_iters_enabled()) {
-		struct printbuf buf = PRINTBUF;
-
-		bch2_trans_paths_to_text(&buf, trans);
-		trace_trans_restart_too_many_iters(trans, _THIS_IP_, buf.buf);
-		printbuf_exit(&buf);
-	}
-
-	count_event(trans->c, trans_restart_too_many_iters);
-
-	return btree_trans_restart(trans, BCH_ERR_transaction_restart_too_many_iters);
-}
-
-static noinline void btree_path_overflow(struct btree_trans *trans)
-{
-	bch2_dump_trans_paths_updates(trans);
-	bch_err(trans->c, "trans path overflow");
-}
-
-static noinline void btree_paths_realloc(struct btree_trans *trans)
-{
-	unsigned nr = trans->nr_paths * 2;
-
-	void *p = kzalloc(BITS_TO_LONGS(nr) * sizeof(unsigned long) +
-			  sizeof(struct btree_trans_paths) +
-			  nr * sizeof(struct btree_path) +
-			  nr * sizeof(btree_path_idx_t) + 8 +
-			  nr * sizeof(struct btree_insert_entry), GFP_KERNEL|__GFP_NOFAIL);
-
-	unsigned long *paths_allocated = p;
-	memcpy(paths_allocated, trans->paths_allocated, BITS_TO_LONGS(trans->nr_paths) * sizeof(unsigned long));
-	p += BITS_TO_LONGS(nr) * sizeof(unsigned long);
-
-	p += sizeof(struct btree_trans_paths);
-	struct btree_path *paths = p;
-	*trans_paths_nr(paths) = nr;
-	memcpy(paths, trans->paths, trans->nr_paths * sizeof(struct btree_path));
-	p += nr * sizeof(struct btree_path);
-
-	btree_path_idx_t *sorted = p;
-	memcpy(sorted, trans->sorted, trans->nr_sorted * sizeof(btree_path_idx_t));
-	p += nr * sizeof(btree_path_idx_t) + 8;
-
-	struct btree_insert_entry *updates = p;
-	memcpy(updates, trans->updates, trans->nr_paths * sizeof(struct btree_insert_entry));
-
-	unsigned long *old = trans->paths_allocated;
-
-	rcu_assign_pointer(trans->paths_allocated,	paths_allocated);
-	rcu_assign_pointer(trans->paths,		paths);
-	rcu_assign_pointer(trans->sorted,		sorted);
-	rcu_assign_pointer(trans->updates,		updates);
-
-	trans->nr_paths		= nr;
-
-	if (old != trans->_paths_allocated)
-		kfree_rcu_mightsleep(old);
-}
-
-static inline btree_path_idx_t btree_path_alloc(struct btree_trans *trans,
-						btree_path_idx_t pos)
-{
-	btree_path_idx_t idx = find_first_zero_bit(trans->paths_allocated, trans->nr_paths);
-
-	if (unlikely(idx == trans->nr_paths)) {
-		if (trans->nr_paths == BTREE_ITER_MAX) {
-			btree_path_overflow(trans);
-			return 0;
-		}
-
-		btree_paths_realloc(trans);
-	}
-
-	/*
-	 * Do this before marking the new path as allocated, since it won't be
-	 * initialized yet:
-	 */
-	if (unlikely(idx > trans->nr_paths_max))
-		bch2_trans_update_max_paths(trans);
-
-	__set_bit(idx, trans->paths_allocated);
-
-	struct btree_path *path = &trans->paths[idx];
-	path->ref		= 0;
-	path->intent_ref	= 0;
-	path->nodes_locked	= 0;
-
-	btree_path_list_add(trans, pos, idx);
-	trans->paths_sorted = false;
-	return idx;
-}
-
-btree_path_idx_t bch2_path_get(struct btree_trans *trans,
-			     enum btree_id btree_id, struct bpos pos,
-			     unsigned locks_want, unsigned level,
-			     unsigned flags, unsigned long ip)
-{
-	struct btree_path *path;
-	bool cached = flags & BTREE_ITER_CACHED;
-	bool intent = flags & BTREE_ITER_INTENT;
-	struct trans_for_each_path_inorder_iter iter;
-	btree_path_idx_t path_pos = 0, path_idx;
-
-	bch2_trans_verify_not_in_restart(trans);
-	bch2_trans_verify_locks(trans);
-
-	btree_trans_sort_paths(trans);
-
-	trans_for_each_path_inorder(trans, path, iter) {
-		if (__btree_path_cmp(path,
-				     btree_id,
-				     cached,
-				     pos,
-				     level) > 0)
-			break;
-
-		path_pos = iter.path_idx;
-	}
-
-	if (path_pos &&
-	    trans->paths[path_pos].cached	== cached &&
-	    trans->paths[path_pos].btree_id	== btree_id &&
-	    trans->paths[path_pos].level	== level) {
-		__btree_path_get(trans->paths + path_pos, intent);
-		path_idx = bch2_btree_path_set_pos(trans, path_pos, pos, intent, ip);
-		path = trans->paths + path_idx;
-	} else {
-		path_idx = btree_path_alloc(trans, path_pos);
-		path = trans->paths + path_idx;
-
-		__btree_path_get(path, intent);
-		path->pos			= pos;
-		path->btree_id			= btree_id;
-		path->cached			= cached;
-		path->uptodate			= BTREE_ITER_NEED_TRAVERSE;
-		path->should_be_locked		= false;
-		path->level			= level;
-		path->locks_want		= locks_want;
-		path->nodes_locked		= 0;
-		for (unsigned i = 0; i < ARRAY_SIZE(path->l); i++)
-			path->l[i].b		= ERR_PTR(-BCH_ERR_no_btree_node_init);
-#ifdef TRACK_PATH_ALLOCATED
-		path->ip_allocated		= ip;
-#endif
-		trans->paths_sorted		= false;
-	}
-
-	if (!(flags & BTREE_ITER_NOPRESERVE))
-		path->preserve = true;
-
-	if (path->intent_ref)
-		locks_want = max(locks_want, level + 1);
-
-	/*
-	 * If the path has locks_want greater than requested, we don't downgrade
-	 * it here - on transaction restart because btree node split needs to
-	 * upgrade locks, we might be putting/getting the iterator again.
-	 * Downgrading iterators only happens via bch2_trans_downgrade(), after
-	 * a successful transaction commit.
-	 */
-
-	locks_want = min(locks_want, BTREE_MAX_DEPTH);
-	if (locks_want > path->locks_want)
-		bch2_btree_path_upgrade_noupgrade_sibs(trans, path, locks_want, NULL);
-
-	return path_idx;
-}
-
-struct bkey_s_c bch2_btree_path_peek_slot(struct btree_path *path, struct bkey *u)
-{
-
-	struct btree_path_level *l = path_l(path);
-	struct bkey_packed *_k;
-	struct bkey_s_c k;
-
-	if (unlikely(!l->b))
-		return bkey_s_c_null;
-
-	EBUG_ON(path->uptodate != BTREE_ITER_UPTODATE);
-	EBUG_ON(!btree_node_locked(path, path->level));
-
-	if (!path->cached) {
-		_k = bch2_btree_node_iter_peek_all(&l->iter, l->b);
-		k = _k ? bkey_disassemble(l->b, _k, u) : bkey_s_c_null;
-
-		EBUG_ON(k.k && bkey_deleted(k.k) && bpos_eq(k.k->p, path->pos));
-
-		if (!k.k || !bpos_eq(path->pos, k.k->p))
-			goto hole;
-	} else {
-		struct bkey_cached *ck = (void *) path->l[0].b;
-
-		EBUG_ON(ck &&
-			(path->btree_id != ck->key.btree_id ||
-			 !bkey_eq(path->pos, ck->key.pos)));
-		if (!ck || !ck->valid)
-			return bkey_s_c_null;
-
-		*u = ck->k->k;
-		k = bkey_i_to_s_c(ck->k);
-	}
-
-	return k;
-hole:
-	bkey_init(u);
-	u->p = path->pos;
-	return (struct bkey_s_c) { u, NULL };
-}
-
-/* Btree iterators: */
-
-int __must_check
-__bch2_btree_iter_traverse(struct btree_iter *iter)
-{
-	return bch2_btree_path_traverse(iter->trans, iter->path, iter->flags);
-}
-
-int __must_check
-bch2_btree_iter_traverse(struct btree_iter *iter)
-{
-	struct btree_trans *trans = iter->trans;
-	int ret;
-
-	iter->path = bch2_btree_path_set_pos(trans, iter->path,
-					btree_iter_search_key(iter),
-					iter->flags & BTREE_ITER_INTENT,
-					btree_iter_ip_allocated(iter));
-
-	ret = bch2_btree_path_traverse(iter->trans, iter->path, iter->flags);
-	if (ret)
-		return ret;
-
-	btree_path_set_should_be_locked(trans->paths + iter->path);
-	return 0;
-}
-
-/* Iterate across nodes (leaf and interior nodes) */
-
-struct btree *bch2_btree_iter_peek_node(struct btree_iter *iter)
-{
-	struct btree_trans *trans = iter->trans;
-	struct btree *b = NULL;
-	int ret;
-
-	EBUG_ON(trans->paths[iter->path].cached);
-	bch2_btree_iter_verify(iter);
-
-	ret = bch2_btree_path_traverse(trans, iter->path, iter->flags);
-	if (ret)
-		goto err;
-
-	struct btree_path *path = btree_iter_path(trans, iter);
-	b = btree_path_node(path, path->level);
-	if (!b)
-		goto out;
-
-	BUG_ON(bpos_lt(b->key.k.p, iter->pos));
-
-	bkey_init(&iter->k);
-	iter->k.p = iter->pos = b->key.k.p;
-
-	iter->path = bch2_btree_path_set_pos(trans, iter->path, b->key.k.p,
-					iter->flags & BTREE_ITER_INTENT,
-					btree_iter_ip_allocated(iter));
-	btree_path_set_should_be_locked(btree_iter_path(trans, iter));
-out:
-	bch2_btree_iter_verify_entry_exit(iter);
-	bch2_btree_iter_verify(iter);
-
-	return b;
-err:
-	b = ERR_PTR(ret);
-	goto out;
-}
-
-struct btree *bch2_btree_iter_peek_node_and_restart(struct btree_iter *iter)
-{
-	struct btree *b;
-
-	while (b = bch2_btree_iter_peek_node(iter),
-	       bch2_err_matches(PTR_ERR_OR_ZERO(b), BCH_ERR_transaction_restart))
-		bch2_trans_begin(iter->trans);
-
-	return b;
-}
-
-struct btree *bch2_btree_iter_next_node(struct btree_iter *iter)
-{
-	struct btree_trans *trans = iter->trans;
-	struct btree *b = NULL;
-	int ret;
-
-	EBUG_ON(trans->paths[iter->path].cached);
-	bch2_trans_verify_not_in_restart(trans);
-	bch2_btree_iter_verify(iter);
-
-	struct btree_path *path = btree_iter_path(trans, iter);
-
-	/* already at end? */
-	if (!btree_path_node(path, path->level))
-		return NULL;
-
-	/* got to end? */
-	if (!btree_path_node(path, path->level + 1)) {
-		btree_path_set_level_up(trans, path);
-		return NULL;
-	}
-
-	if (!bch2_btree_node_relock(trans, path, path->level + 1)) {
-		__bch2_btree_path_unlock(trans, path);
-		path->l[path->level].b		= ERR_PTR(-BCH_ERR_no_btree_node_relock);
-		path->l[path->level + 1].b	= ERR_PTR(-BCH_ERR_no_btree_node_relock);
-		btree_path_set_dirty(path, BTREE_ITER_NEED_TRAVERSE);
-		trace_and_count(trans->c, trans_restart_relock_next_node, trans, _THIS_IP_, path);
-		ret = btree_trans_restart(trans, BCH_ERR_transaction_restart_relock);
-		goto err;
-	}
-
-	b = btree_path_node(path, path->level + 1);
-
-	if (bpos_eq(iter->pos, b->key.k.p)) {
-		__btree_path_set_level_up(trans, path, path->level++);
-	} else {
-		/*
-		 * Haven't gotten to the end of the parent node: go back down to
-		 * the next child node
-		 */
-		iter->path = bch2_btree_path_set_pos(trans, iter->path,
-					bpos_successor(iter->pos),
-					iter->flags & BTREE_ITER_INTENT,
-					btree_iter_ip_allocated(iter));
-
-		path = btree_iter_path(trans, iter);
-		btree_path_set_level_down(trans, path, iter->min_depth);
-
-		ret = bch2_btree_path_traverse(trans, iter->path, iter->flags);
-		if (ret)
-			goto err;
-
-		path = btree_iter_path(trans, iter);
-		b = path->l[path->level].b;
-	}
-
-	bkey_init(&iter->k);
-	iter->k.p = iter->pos = b->key.k.p;
-
-	iter->path = bch2_btree_path_set_pos(trans, iter->path, b->key.k.p,
-					iter->flags & BTREE_ITER_INTENT,
-					btree_iter_ip_allocated(iter));
-	btree_path_set_should_be_locked(btree_iter_path(trans, iter));
-	EBUG_ON(btree_iter_path(trans, iter)->uptodate);
-out:
-	bch2_btree_iter_verify_entry_exit(iter);
-	bch2_btree_iter_verify(iter);
-
-	return b;
-err:
-	b = ERR_PTR(ret);
-	goto out;
-}
-
-/* Iterate across keys (in leaf nodes only) */
-
-inline bool bch2_btree_iter_advance(struct btree_iter *iter)
-{
-	struct bpos pos = iter->k.p;
-	bool ret = !(iter->flags & BTREE_ITER_ALL_SNAPSHOTS
-		     ? bpos_eq(pos, SPOS_MAX)
-		     : bkey_eq(pos, SPOS_MAX));
-
-	if (ret && !(iter->flags & BTREE_ITER_IS_EXTENTS))
-		pos = bkey_successor(iter, pos);
-	bch2_btree_iter_set_pos(iter, pos);
-	return ret;
-}
-
-inline bool bch2_btree_iter_rewind(struct btree_iter *iter)
-{
-	struct bpos pos = bkey_start_pos(&iter->k);
-	bool ret = !(iter->flags & BTREE_ITER_ALL_SNAPSHOTS
-		     ? bpos_eq(pos, POS_MIN)
-		     : bkey_eq(pos, POS_MIN));
-
-	if (ret && !(iter->flags & BTREE_ITER_IS_EXTENTS))
-		pos = bkey_predecessor(iter, pos);
-	bch2_btree_iter_set_pos(iter, pos);
-	return ret;
-}
-
-static noinline
-void bch2_btree_trans_peek_prev_updates(struct btree_trans *trans, struct btree_iter *iter,
-					struct bkey_s_c *k)
-{
-	struct bpos end = path_l(btree_iter_path(trans, iter))->b->data->min_key;
-
-	trans_for_each_update(trans, i)
-		if (!i->key_cache_already_flushed &&
-		    i->btree_id == iter->btree_id &&
-		    bpos_le(i->k->k.p, iter->pos) &&
-		    bpos_ge(i->k->k.p, k->k ? k->k->p : end)) {
-			iter->k = i->k->k;
-			*k = bkey_i_to_s_c(i->k);
-		}
-}
-
-static noinline
-void bch2_btree_trans_peek_updates(struct btree_trans *trans, struct btree_iter *iter,
-				   struct bkey_s_c *k)
-{
-	struct btree_path *path = btree_iter_path(trans, iter);
-	struct bpos end = path_l(path)->b->key.k.p;
-
-	trans_for_each_update(trans, i)
-		if (!i->key_cache_already_flushed &&
-		    i->btree_id == iter->btree_id &&
-		    bpos_ge(i->k->k.p, path->pos) &&
-		    bpos_le(i->k->k.p, k->k ? k->k->p : end)) {
-			iter->k = i->k->k;
-			*k = bkey_i_to_s_c(i->k);
-		}
-}
-
-static noinline
-void bch2_btree_trans_peek_slot_updates(struct btree_trans *trans, struct btree_iter *iter,
-					struct bkey_s_c *k)
-{
-	trans_for_each_update(trans, i)
-		if (!i->key_cache_already_flushed &&
-		    i->btree_id == iter->btree_id &&
-		    bpos_eq(i->k->k.p, iter->pos)) {
-			iter->k = i->k->k;
-			*k = bkey_i_to_s_c(i->k);
-		}
-}
-
-static struct bkey_i *bch2_btree_journal_peek(struct btree_trans *trans,
-					      struct btree_iter *iter,
-					      struct bpos end_pos)
-{
-	struct btree_path *path = btree_iter_path(trans, iter);
-
-	return bch2_journal_keys_peek_upto(trans->c, iter->btree_id,
-					   path->level,
-					   path->pos,
-					   end_pos,
-					   &iter->journal_idx);
-}
-
-static noinline
-struct bkey_s_c btree_trans_peek_slot_journal(struct btree_trans *trans,
-					      struct btree_iter *iter)
-{
-	struct btree_path *path = btree_iter_path(trans, iter);
-	struct bkey_i *k = bch2_btree_journal_peek(trans, iter, path->pos);
-
-	if (k) {
-		iter->k = k->k;
-		return bkey_i_to_s_c(k);
-	} else {
-		return bkey_s_c_null;
-	}
-}
-
-static noinline
-struct bkey_s_c btree_trans_peek_journal(struct btree_trans *trans,
-					 struct btree_iter *iter,
-					 struct bkey_s_c k)
-{
-	struct btree_path *path = btree_iter_path(trans, iter);
-	struct bkey_i *next_journal =
-		bch2_btree_journal_peek(trans, iter,
-				k.k ? k.k->p : path_l(path)->b->key.k.p);
-
-	if (next_journal) {
-		iter->k = next_journal->k;
-		k = bkey_i_to_s_c(next_journal);
-	}
-
-	return k;
-}
-
-/*
- * Checks btree key cache for key at iter->pos and returns it if present, or
- * bkey_s_c_null:
- */
-static noinline
-struct bkey_s_c btree_trans_peek_key_cache(struct btree_iter *iter, struct bpos pos)
-{
-	struct btree_trans *trans = iter->trans;
-	struct bch_fs *c = trans->c;
-	struct bkey u;
-	struct bkey_s_c k;
-	int ret;
-
-	if ((iter->flags & BTREE_ITER_KEY_CACHE_FILL) &&
-	    bpos_eq(iter->pos, pos))
-		return bkey_s_c_null;
-
-	if (!bch2_btree_key_cache_find(c, iter->btree_id, pos))
-		return bkey_s_c_null;
-
-	if (!iter->key_cache_path)
-		iter->key_cache_path = bch2_path_get(trans, iter->btree_id, pos,
-						     iter->flags & BTREE_ITER_INTENT, 0,
-						     iter->flags|BTREE_ITER_CACHED|
-						     BTREE_ITER_CACHED_NOFILL,
-						     _THIS_IP_);
-
-	iter->key_cache_path = bch2_btree_path_set_pos(trans, iter->key_cache_path, pos,
-					iter->flags & BTREE_ITER_INTENT,
-					btree_iter_ip_allocated(iter));
-
-	ret =   bch2_btree_path_traverse(trans, iter->key_cache_path,
-					 iter->flags|BTREE_ITER_CACHED) ?:
-		bch2_btree_path_relock(trans, btree_iter_path(trans, iter), _THIS_IP_);
-	if (unlikely(ret))
-		return bkey_s_c_err(ret);
-
-	btree_path_set_should_be_locked(trans->paths + iter->key_cache_path);
-
-	k = bch2_btree_path_peek_slot(trans->paths + iter->key_cache_path, &u);
-	if (k.k && !bkey_err(k)) {
-		iter->k = u;
-		k.k = &iter->k;
-	}
-	return k;
-}
-
-static struct bkey_s_c __bch2_btree_iter_peek(struct btree_iter *iter, struct bpos search_key)
-{
-	struct btree_trans *trans = iter->trans;
-	struct bkey_s_c k, k2;
-	int ret;
-
-	EBUG_ON(btree_iter_path(trans, iter)->cached);
-	bch2_btree_iter_verify(iter);
-
-	while (1) {
-		struct btree_path_level *l;
-
-		iter->path = bch2_btree_path_set_pos(trans, iter->path, search_key,
-					iter->flags & BTREE_ITER_INTENT,
-					btree_iter_ip_allocated(iter));
-
-		ret = bch2_btree_path_traverse(trans, iter->path, iter->flags);
-		if (unlikely(ret)) {
-			/* ensure that iter->k is consistent with iter->pos: */
-			bch2_btree_iter_set_pos(iter, iter->pos);
-			k = bkey_s_c_err(ret);
-			goto out;
-		}
-
-		struct btree_path *path = btree_iter_path(trans, iter);
-		l = path_l(path);
-
-		if (unlikely(!l->b)) {
-			/* No btree nodes at requested level: */
-			bch2_btree_iter_set_pos(iter, SPOS_MAX);
-			k = bkey_s_c_null;
-			goto out;
-		}
-
-		btree_path_set_should_be_locked(path);
-
-		k = btree_path_level_peek_all(trans->c, l, &iter->k);
-
-		if (unlikely(iter->flags & BTREE_ITER_WITH_KEY_CACHE) &&
-		    k.k &&
-		    (k2 = btree_trans_peek_key_cache(iter, k.k->p)).k) {
-			k = k2;
-			ret = bkey_err(k);
-			if (ret) {
-				bch2_btree_iter_set_pos(iter, iter->pos);
-				goto out;
-			}
-		}
-
-		if (unlikely(iter->flags & BTREE_ITER_WITH_JOURNAL))
-			k = btree_trans_peek_journal(trans, iter, k);
-
-		if (unlikely((iter->flags & BTREE_ITER_WITH_UPDATES) &&
-			     trans->nr_updates))
-			bch2_btree_trans_peek_updates(trans, iter, &k);
-
-		if (k.k && bkey_deleted(k.k)) {
-			/*
-			 * If we've got a whiteout, and it's after the search
-			 * key, advance the search key to the whiteout instead
-			 * of just after the whiteout - it might be a btree
-			 * whiteout, with a real key at the same position, since
-			 * in the btree deleted keys sort before non deleted.
-			 */
-			search_key = !bpos_eq(search_key, k.k->p)
-				? k.k->p
-				: bpos_successor(k.k->p);
-			continue;
-		}
-
-		if (likely(k.k)) {
-			break;
-		} else if (likely(!bpos_eq(l->b->key.k.p, SPOS_MAX))) {
-			/* Advance to next leaf node: */
-			search_key = bpos_successor(l->b->key.k.p);
-		} else {
-			/* End of btree: */
-			bch2_btree_iter_set_pos(iter, SPOS_MAX);
-			k = bkey_s_c_null;
-			goto out;
-		}
-	}
-out:
-	bch2_btree_iter_verify(iter);
-
-	return k;
-}
-
-/**
- * bch2_btree_iter_peek_upto() - returns first key greater than or equal to
- * iterator's current position
- * @iter:	iterator to peek from
- * @end:	search limit: returns keys less than or equal to @end
- *
- * Returns:	key if found, or an error extractable with bkey_err().
- */
-struct bkey_s_c bch2_btree_iter_peek_upto(struct btree_iter *iter, struct bpos end)
-{
-	struct btree_trans *trans = iter->trans;
-	struct bpos search_key = btree_iter_search_key(iter);
-	struct bkey_s_c k;
-	struct bpos iter_pos;
-	int ret;
-
-	EBUG_ON((iter->flags & BTREE_ITER_FILTER_SNAPSHOTS) && bkey_eq(end, POS_MAX));
-
-	if (iter->update_path) {
-		bch2_path_put_nokeep(trans, iter->update_path,
-				     iter->flags & BTREE_ITER_INTENT);
-		iter->update_path = 0;
-	}
-
-	bch2_btree_iter_verify_entry_exit(iter);
-
-	while (1) {
-		k = __bch2_btree_iter_peek(iter, search_key);
-		if (unlikely(!k.k))
-			goto end;
-		if (unlikely(bkey_err(k)))
-			goto out_no_locked;
-
-		/*
-		 * We need to check against @end before FILTER_SNAPSHOTS because
-		 * if we get to a different inode that requested we might be
-		 * seeing keys for a different snapshot tree that will all be
-		 * filtered out.
-		 *
-		 * But we can't do the full check here, because bkey_start_pos()
-		 * isn't monotonically increasing before FILTER_SNAPSHOTS, and
-		 * that's what we check against in extents mode:
-		 */
-		if (k.k->p.inode > end.inode)
-			goto end;
-
-		if (iter->update_path &&
-		    !bkey_eq(trans->paths[iter->update_path].pos, k.k->p)) {
-			bch2_path_put_nokeep(trans, iter->update_path,
-					     iter->flags & BTREE_ITER_INTENT);
-			iter->update_path = 0;
-		}
-
-		if ((iter->flags & BTREE_ITER_FILTER_SNAPSHOTS) &&
-		    (iter->flags & BTREE_ITER_INTENT) &&
-		    !(iter->flags & BTREE_ITER_IS_EXTENTS) &&
-		    !iter->update_path) {
-			struct bpos pos = k.k->p;
-
-			if (pos.snapshot < iter->snapshot) {
-				search_key = bpos_successor(k.k->p);
-				continue;
-			}
-
-			pos.snapshot = iter->snapshot;
-
-			/*
-			 * advance, same as on exit for iter->path, but only up
-			 * to snapshot
-			 */
-			__btree_path_get(trans->paths + iter->path, iter->flags & BTREE_ITER_INTENT);
-			iter->update_path = iter->path;
-
-			iter->update_path = bch2_btree_path_set_pos(trans,
-						iter->update_path, pos,
-						iter->flags & BTREE_ITER_INTENT,
-						_THIS_IP_);
-			ret = bch2_btree_path_traverse(trans, iter->update_path, iter->flags);
-			if (unlikely(ret)) {
-				k = bkey_s_c_err(ret);
-				goto out_no_locked;
-			}
-		}
-
-		/*
-		 * We can never have a key in a leaf node at POS_MAX, so
-		 * we don't have to check these successor() calls:
-		 */
-		if ((iter->flags & BTREE_ITER_FILTER_SNAPSHOTS) &&
-		    !bch2_snapshot_is_ancestor(trans->c,
-					       iter->snapshot,
-					       k.k->p.snapshot)) {
-			search_key = bpos_successor(k.k->p);
-			continue;
-		}
-
-		if (bkey_whiteout(k.k) &&
-		    !(iter->flags & BTREE_ITER_ALL_SNAPSHOTS)) {
-			search_key = bkey_successor(iter, k.k->p);
-			continue;
-		}
-
-		/*
-		 * iter->pos should be mononotically increasing, and always be
-		 * equal to the key we just returned - except extents can
-		 * straddle iter->pos:
-		 */
-		if (!(iter->flags & BTREE_ITER_IS_EXTENTS))
-			iter_pos = k.k->p;
-		else
-			iter_pos = bkey_max(iter->pos, bkey_start_pos(k.k));
-
-		if (unlikely(!(iter->flags & BTREE_ITER_IS_EXTENTS)
-			     ? bkey_gt(iter_pos, end)
-			     : bkey_ge(iter_pos, end)))
-			goto end;
-
-		break;
-	}
-
-	iter->pos = iter_pos;
-
-	iter->path = bch2_btree_path_set_pos(trans, iter->path, k.k->p,
-				iter->flags & BTREE_ITER_INTENT,
-				btree_iter_ip_allocated(iter));
-
-	btree_path_set_should_be_locked(btree_iter_path(trans, iter));
-out_no_locked:
-	if (iter->update_path) {
-		ret = bch2_btree_path_relock(trans, trans->paths + iter->update_path, _THIS_IP_);
-		if (unlikely(ret))
-			k = bkey_s_c_err(ret);
-		else
-			btree_path_set_should_be_locked(trans->paths + iter->update_path);
-	}
-
-	if (!(iter->flags & BTREE_ITER_ALL_SNAPSHOTS))
-		iter->pos.snapshot = iter->snapshot;
-
-	ret = bch2_btree_iter_verify_ret(iter, k);
-	if (unlikely(ret)) {
-		bch2_btree_iter_set_pos(iter, iter->pos);
-		k = bkey_s_c_err(ret);
-	}
-
-	bch2_btree_iter_verify_entry_exit(iter);
-
-	return k;
-end:
-	bch2_btree_iter_set_pos(iter, end);
-	k = bkey_s_c_null;
-	goto out_no_locked;
-}
-
-/**
- * bch2_btree_iter_next() - returns first key greater than iterator's current
- * position
- * @iter:	iterator to peek from
- *
- * Returns:	key if found, or an error extractable with bkey_err().
- */
-struct bkey_s_c bch2_btree_iter_next(struct btree_iter *iter)
-{
-	if (!bch2_btree_iter_advance(iter))
-		return bkey_s_c_null;
-
-	return bch2_btree_iter_peek(iter);
-}
-
-/**
- * bch2_btree_iter_peek_prev() - returns first key less than or equal to
- * iterator's current position
- * @iter:	iterator to peek from
- *
- * Returns:	key if found, or an error extractable with bkey_err().
- */
-struct bkey_s_c bch2_btree_iter_peek_prev(struct btree_iter *iter)
-{
-	struct btree_trans *trans = iter->trans;
-	struct bpos search_key = iter->pos;
-	struct bkey_s_c k;
-	struct bkey saved_k;
-	const struct bch_val *saved_v;
-	btree_path_idx_t saved_path = 0;
-	int ret;
-
-	EBUG_ON(btree_iter_path(trans, iter)->cached ||
-		btree_iter_path(trans, iter)->level);
-
-	if (iter->flags & BTREE_ITER_WITH_JOURNAL)
-		return bkey_s_c_err(-EIO);
-
-	bch2_btree_iter_verify(iter);
-	bch2_btree_iter_verify_entry_exit(iter);
-
-	if (iter->flags & BTREE_ITER_FILTER_SNAPSHOTS)
-		search_key.snapshot = U32_MAX;
-
-	while (1) {
-		iter->path = bch2_btree_path_set_pos(trans, iter->path, search_key,
-						iter->flags & BTREE_ITER_INTENT,
-						btree_iter_ip_allocated(iter));
-
-		ret = bch2_btree_path_traverse(trans, iter->path, iter->flags);
-		if (unlikely(ret)) {
-			/* ensure that iter->k is consistent with iter->pos: */
-			bch2_btree_iter_set_pos(iter, iter->pos);
-			k = bkey_s_c_err(ret);
-			goto out_no_locked;
-		}
-
-		struct btree_path *path = btree_iter_path(trans, iter);
-
-		k = btree_path_level_peek(trans, path, &path->l[0], &iter->k);
-		if (!k.k ||
-		    ((iter->flags & BTREE_ITER_IS_EXTENTS)
-		     ? bpos_ge(bkey_start_pos(k.k), search_key)
-		     : bpos_gt(k.k->p, search_key)))
-			k = btree_path_level_prev(trans, path, &path->l[0], &iter->k);
-
-		if (unlikely((iter->flags & BTREE_ITER_WITH_UPDATES) &&
-			     trans->nr_updates))
-			bch2_btree_trans_peek_prev_updates(trans, iter, &k);
-
-		if (likely(k.k)) {
-			if (iter->flags & BTREE_ITER_FILTER_SNAPSHOTS) {
-				if (k.k->p.snapshot == iter->snapshot)
-					goto got_key;
-
-				/*
-				 * If we have a saved candidate, and we're no
-				 * longer at the same _key_ (not pos), return
-				 * that candidate
-				 */
-				if (saved_path && !bkey_eq(k.k->p, saved_k.p)) {
-					bch2_path_put_nokeep(trans, iter->path,
-						      iter->flags & BTREE_ITER_INTENT);
-					iter->path = saved_path;
-					saved_path = 0;
-					iter->k	= saved_k;
-					k.v	= saved_v;
-					goto got_key;
-				}
-
-				if (bch2_snapshot_is_ancestor(trans->c,
-							      iter->snapshot,
-							      k.k->p.snapshot)) {
-					if (saved_path)
-						bch2_path_put_nokeep(trans, saved_path,
-						      iter->flags & BTREE_ITER_INTENT);
-					saved_path = btree_path_clone(trans, iter->path,
-								iter->flags & BTREE_ITER_INTENT);
-					path = btree_iter_path(trans, iter);
-					saved_k = *k.k;
-					saved_v = k.v;
-				}
-
-				search_key = bpos_predecessor(k.k->p);
-				continue;
-			}
-got_key:
-			if (bkey_whiteout(k.k) &&
-			    !(iter->flags & BTREE_ITER_ALL_SNAPSHOTS)) {
-				search_key = bkey_predecessor(iter, k.k->p);
-				if (iter->flags & BTREE_ITER_FILTER_SNAPSHOTS)
-					search_key.snapshot = U32_MAX;
-				continue;
-			}
-
-			btree_path_set_should_be_locked(path);
-			break;
-		} else if (likely(!bpos_eq(path->l[0].b->data->min_key, POS_MIN))) {
-			/* Advance to previous leaf node: */
-			search_key = bpos_predecessor(path->l[0].b->data->min_key);
-		} else {
-			/* Start of btree: */
-			bch2_btree_iter_set_pos(iter, POS_MIN);
-			k = bkey_s_c_null;
-			goto out_no_locked;
-		}
-	}
-
-	EBUG_ON(bkey_gt(bkey_start_pos(k.k), iter->pos));
-
-	/* Extents can straddle iter->pos: */
-	if (bkey_lt(k.k->p, iter->pos))
-		iter->pos = k.k->p;
-
-	if (iter->flags & BTREE_ITER_FILTER_SNAPSHOTS)
-		iter->pos.snapshot = iter->snapshot;
-out_no_locked:
-	if (saved_path)
-		bch2_path_put_nokeep(trans, saved_path, iter->flags & BTREE_ITER_INTENT);
-
-	bch2_btree_iter_verify_entry_exit(iter);
-	bch2_btree_iter_verify(iter);
-
-	return k;
-}
-
-/**
- * bch2_btree_iter_prev() - returns first key less than iterator's current
- * position
- * @iter:	iterator to peek from
- *
- * Returns:	key if found, or an error extractable with bkey_err().
- */
-struct bkey_s_c bch2_btree_iter_prev(struct btree_iter *iter)
-{
-	if (!bch2_btree_iter_rewind(iter))
-		return bkey_s_c_null;
-
-	return bch2_btree_iter_peek_prev(iter);
-}
-
-struct bkey_s_c bch2_btree_iter_peek_slot(struct btree_iter *iter)
-{
-	struct btree_trans *trans = iter->trans;
-	struct bpos search_key;
-	struct bkey_s_c k;
-	int ret;
-
-	bch2_btree_iter_verify(iter);
-	bch2_btree_iter_verify_entry_exit(iter);
-	EBUG_ON(btree_iter_path(trans, iter)->level && (iter->flags & BTREE_ITER_WITH_KEY_CACHE));
-
-	/* extents can't span inode numbers: */
-	if ((iter->flags & BTREE_ITER_IS_EXTENTS) &&
-	    unlikely(iter->pos.offset == KEY_OFFSET_MAX)) {
-		if (iter->pos.inode == KEY_INODE_MAX)
-			return bkey_s_c_null;
-
-		bch2_btree_iter_set_pos(iter, bpos_nosnap_successor(iter->pos));
-	}
-
-	search_key = btree_iter_search_key(iter);
-	iter->path = bch2_btree_path_set_pos(trans, iter->path, search_key,
-					iter->flags & BTREE_ITER_INTENT,
-					btree_iter_ip_allocated(iter));
-
-	ret = bch2_btree_path_traverse(trans, iter->path, iter->flags);
-	if (unlikely(ret)) {
-		k = bkey_s_c_err(ret);
-		goto out_no_locked;
-	}
-
-	if ((iter->flags & BTREE_ITER_CACHED) ||
-	    !(iter->flags & (BTREE_ITER_IS_EXTENTS|BTREE_ITER_FILTER_SNAPSHOTS))) {
-		k = bkey_s_c_null;
-
-		if (unlikely((iter->flags & BTREE_ITER_WITH_UPDATES) &&
-			     trans->nr_updates)) {
-			bch2_btree_trans_peek_slot_updates(trans, iter, &k);
-			if (k.k)
-				goto out;
-		}
-
-		if (unlikely(iter->flags & BTREE_ITER_WITH_JOURNAL) &&
-		    (k = btree_trans_peek_slot_journal(trans, iter)).k)
-			goto out;
-
-		if (unlikely(iter->flags & BTREE_ITER_WITH_KEY_CACHE) &&
-		    (k = btree_trans_peek_key_cache(iter, iter->pos)).k) {
-			if (!bkey_err(k))
-				iter->k = *k.k;
-			/* We're not returning a key from iter->path: */
-			goto out_no_locked;
-		}
-
-		k = bch2_btree_path_peek_slot(trans->paths + iter->path, &iter->k);
-		if (unlikely(!k.k))
-			goto out_no_locked;
-	} else {
-		struct bpos next;
-		struct bpos end = iter->pos;
-
-		if (iter->flags & BTREE_ITER_IS_EXTENTS)
-			end.offset = U64_MAX;
-
-		EBUG_ON(btree_iter_path(trans, iter)->level);
-
-		if (iter->flags & BTREE_ITER_INTENT) {
-			struct btree_iter iter2;
-
-			bch2_trans_copy_iter(&iter2, iter);
-			k = bch2_btree_iter_peek_upto(&iter2, end);
-
-			if (k.k && !bkey_err(k)) {
-				iter->k = iter2.k;
-				k.k = &iter->k;
-			}
-			bch2_trans_iter_exit(trans, &iter2);
-		} else {
-			struct bpos pos = iter->pos;
-
-			k = bch2_btree_iter_peek_upto(iter, end);
-			if (unlikely(bkey_err(k)))
-				bch2_btree_iter_set_pos(iter, pos);
-			else
-				iter->pos = pos;
-		}
-
-		if (unlikely(bkey_err(k)))
-			goto out_no_locked;
-
-		next = k.k ? bkey_start_pos(k.k) : POS_MAX;
-
-		if (bkey_lt(iter->pos, next)) {
-			bkey_init(&iter->k);
-			iter->k.p = iter->pos;
-
-			if (iter->flags & BTREE_ITER_IS_EXTENTS) {
-				bch2_key_resize(&iter->k,
-						min_t(u64, KEY_SIZE_MAX,
-						      (next.inode == iter->pos.inode
-						       ? next.offset
-						       : KEY_OFFSET_MAX) -
-						      iter->pos.offset));
-				EBUG_ON(!iter->k.size);
-			}
-
-			k = (struct bkey_s_c) { &iter->k, NULL };
-		}
-	}
-out:
-	btree_path_set_should_be_locked(btree_iter_path(trans, iter));
-out_no_locked:
-	bch2_btree_iter_verify_entry_exit(iter);
-	bch2_btree_iter_verify(iter);
-	ret = bch2_btree_iter_verify_ret(iter, k);
-	if (unlikely(ret))
-		return bkey_s_c_err(ret);
-
-	return k;
-}
-
-struct bkey_s_c bch2_btree_iter_next_slot(struct btree_iter *iter)
-{
-	if (!bch2_btree_iter_advance(iter))
-		return bkey_s_c_null;
-
-	return bch2_btree_iter_peek_slot(iter);
-}
-
-struct bkey_s_c bch2_btree_iter_prev_slot(struct btree_iter *iter)
-{
-	if (!bch2_btree_iter_rewind(iter))
-		return bkey_s_c_null;
-
-	return bch2_btree_iter_peek_slot(iter);
-}
-
-struct bkey_s_c bch2_btree_iter_peek_and_restart_outlined(struct btree_iter *iter)
-{
-	struct bkey_s_c k;
-
-	while (btree_trans_too_many_iters(iter->trans) ||
-	       (k = bch2_btree_iter_peek_type(iter, iter->flags),
-		bch2_err_matches(bkey_err(k), BCH_ERR_transaction_restart)))
-		bch2_trans_begin(iter->trans);
-
-	return k;
-}
-
-/* new transactional stuff: */
-
-#ifdef CONFIG_BCACHEFS_DEBUG
-static void btree_trans_verify_sorted_refs(struct btree_trans *trans)
-{
-	struct btree_path *path;
-	unsigned i;
-
-	BUG_ON(trans->nr_sorted != bitmap_weight(trans->paths_allocated, trans->nr_paths) - 1);
-
-	trans_for_each_path(trans, path, i) {
-		BUG_ON(path->sorted_idx >= trans->nr_sorted);
-		BUG_ON(trans->sorted[path->sorted_idx] != i);
-	}
-
-	for (i = 0; i < trans->nr_sorted; i++) {
-		unsigned idx = trans->sorted[i];
-
-		BUG_ON(!test_bit(idx, trans->paths_allocated));
-		BUG_ON(trans->paths[idx].sorted_idx != i);
-	}
-}
-
-static void btree_trans_verify_sorted(struct btree_trans *trans)
-{
-	struct btree_path *path, *prev = NULL;
-	struct trans_for_each_path_inorder_iter iter;
-
-	if (!bch2_debug_check_iterators)
-		return;
-
-	trans_for_each_path_inorder(trans, path, iter) {
-		if (prev && btree_path_cmp(prev, path) > 0) {
-			__bch2_dump_trans_paths_updates(trans, true);
-			panic("trans paths out of order!\n");
-		}
-		prev = path;
-	}
-}
-#else
-static inline void btree_trans_verify_sorted_refs(struct btree_trans *trans) {}
-static inline void btree_trans_verify_sorted(struct btree_trans *trans) {}
-#endif
-
-void __bch2_btree_trans_sort_paths(struct btree_trans *trans)
-{
-	int i, l = 0, r = trans->nr_sorted, inc = 1;
-	bool swapped;
-
-	btree_trans_verify_sorted_refs(trans);
-
-	if (trans->paths_sorted)
-		goto out;
-
-	/*
-	 * Cocktail shaker sort: this is efficient because iterators will be
-	 * mostly sorted.
-	 */
-	do {
-		swapped = false;
-
-		for (i = inc > 0 ? l : r - 2;
-		     i + 1 < r && i >= l;
-		     i += inc) {
-			if (btree_path_cmp(trans->paths + trans->sorted[i],
-					   trans->paths + trans->sorted[i + 1]) > 0) {
-				swap(trans->sorted[i], trans->sorted[i + 1]);
-				trans->paths[trans->sorted[i]].sorted_idx = i;
-				trans->paths[trans->sorted[i + 1]].sorted_idx = i + 1;
-				swapped = true;
-			}
-		}
-
-		if (inc > 0)
-			--r;
-		else
-			l++;
-		inc = -inc;
-	} while (swapped);
-
-	trans->paths_sorted = true;
-out:
-	btree_trans_verify_sorted(trans);
-}
-
-static inline void btree_path_list_remove(struct btree_trans *trans,
-					  struct btree_path *path)
-{
-	EBUG_ON(path->sorted_idx >= trans->nr_sorted);
-#ifdef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
-	trans->nr_sorted--;
-	memmove_u64s_down_small(trans->sorted + path->sorted_idx,
-				trans->sorted + path->sorted_idx + 1,
-				DIV_ROUND_UP(trans->nr_sorted - path->sorted_idx,
-					     sizeof(u64) / sizeof(btree_path_idx_t)));
-#else
-	array_remove_item(trans->sorted, trans->nr_sorted, path->sorted_idx);
-#endif
-	for (unsigned i = path->sorted_idx; i < trans->nr_sorted; i++)
-		trans->paths[trans->sorted[i]].sorted_idx = i;
-}
-
-static inline void btree_path_list_add(struct btree_trans *trans,
-				       btree_path_idx_t pos,
-				       btree_path_idx_t path_idx)
-{
-	struct btree_path *path = trans->paths + path_idx;
-
-	path->sorted_idx = pos ? trans->paths[pos].sorted_idx + 1 : trans->nr_sorted;
-
-#ifdef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
-	memmove_u64s_up_small(trans->sorted + path->sorted_idx + 1,
-			      trans->sorted + path->sorted_idx,
-			      DIV_ROUND_UP(trans->nr_sorted - path->sorted_idx,
-					   sizeof(u64) / sizeof(btree_path_idx_t)));
-	trans->nr_sorted++;
-	trans->sorted[path->sorted_idx] = path_idx;
-#else
-	array_insert_item(trans->sorted, trans->nr_sorted, path->sorted_idx, path_idx);
-#endif
-
-	for (unsigned i = path->sorted_idx; i < trans->nr_sorted; i++)
-		trans->paths[trans->sorted[i]].sorted_idx = i;
-
-	btree_trans_verify_sorted_refs(trans);
-}
-
-void bch2_trans_iter_exit(struct btree_trans *trans, struct btree_iter *iter)
-{
-	if (iter->update_path)
-		bch2_path_put_nokeep(trans, iter->update_path,
-			      iter->flags & BTREE_ITER_INTENT);
-	if (iter->path)
-		bch2_path_put(trans, iter->path,
-			      iter->flags & BTREE_ITER_INTENT);
-	if (iter->key_cache_path)
-		bch2_path_put(trans, iter->key_cache_path,
-			      iter->flags & BTREE_ITER_INTENT);
-	iter->path		= 0;
-	iter->update_path	= 0;
-	iter->key_cache_path	= 0;
-	iter->trans		= NULL;
-}
-
-void bch2_trans_iter_init_outlined(struct btree_trans *trans,
-			  struct btree_iter *iter,
-			  enum btree_id btree_id, struct bpos pos,
-			  unsigned flags)
-{
-	bch2_trans_iter_init_common(trans, iter, btree_id, pos, 0, 0,
-			       bch2_btree_iter_flags(trans, btree_id, flags),
-			       _RET_IP_);
-}
-
-void bch2_trans_node_iter_init(struct btree_trans *trans,
-			       struct btree_iter *iter,
-			       enum btree_id btree_id,
-			       struct bpos pos,
-			       unsigned locks_want,
-			       unsigned depth,
-			       unsigned flags)
-{
-	flags |= BTREE_ITER_NOT_EXTENTS;
-	flags |= __BTREE_ITER_ALL_SNAPSHOTS;
-	flags |= BTREE_ITER_ALL_SNAPSHOTS;
-
-	bch2_trans_iter_init_common(trans, iter, btree_id, pos, locks_want, depth,
-			       __bch2_btree_iter_flags(trans, btree_id, flags),
-			       _RET_IP_);
-
-	iter->min_depth	= depth;
-
-	struct btree_path *path = btree_iter_path(trans, iter);
-	BUG_ON(path->locks_want	 < min(locks_want, BTREE_MAX_DEPTH));
-	BUG_ON(path->level	!= depth);
-	BUG_ON(iter->min_depth	!= depth);
-}
-
-void bch2_trans_copy_iter(struct btree_iter *dst, struct btree_iter *src)
-{
-	struct btree_trans *trans = src->trans;
-
-	*dst = *src;
-	if (src->path)
-		__btree_path_get(trans->paths + src->path, src->flags & BTREE_ITER_INTENT);
-	if (src->update_path)
-		__btree_path_get(trans->paths + src->update_path, src->flags & BTREE_ITER_INTENT);
-	dst->key_cache_path = 0;
-}
-
-void *__bch2_trans_kmalloc(struct btree_trans *trans, size_t size)
-{
-	struct bch_fs *c = trans->c;
-	unsigned new_top = trans->mem_top + size;
-	unsigned old_bytes = trans->mem_bytes;
-	unsigned new_bytes = roundup_pow_of_two(new_top);
-	int ret;
-	void *new_mem;
-	void *p;
-
-	WARN_ON_ONCE(new_bytes > BTREE_TRANS_MEM_MAX);
-
-	struct btree_transaction_stats *s = btree_trans_stats(trans);
-	s->max_mem = max(s->max_mem, new_bytes);
-
-	new_mem = krealloc(trans->mem, new_bytes, GFP_NOWAIT|__GFP_NOWARN);
-	if (unlikely(!new_mem)) {
-		bch2_trans_unlock(trans);
-
-		new_mem = krealloc(trans->mem, new_bytes, GFP_KERNEL);
-		if (!new_mem && new_bytes <= BTREE_TRANS_MEM_MAX) {
-			new_mem = mempool_alloc(&c->btree_trans_mem_pool, GFP_KERNEL);
-			new_bytes = BTREE_TRANS_MEM_MAX;
-			kfree(trans->mem);
-		}
-
-		if (!new_mem)
-			return ERR_PTR(-BCH_ERR_ENOMEM_trans_kmalloc);
-
-		trans->mem = new_mem;
-		trans->mem_bytes = new_bytes;
-
-		ret = bch2_trans_relock(trans);
-		if (ret)
-			return ERR_PTR(ret);
-	}
-
-	trans->mem = new_mem;
-	trans->mem_bytes = new_bytes;
-
-	if (old_bytes) {
-		trace_and_count(c, trans_restart_mem_realloced, trans, _RET_IP_, new_bytes);
-		return ERR_PTR(btree_trans_restart(trans, BCH_ERR_transaction_restart_mem_realloced));
-	}
-
-	p = trans->mem + trans->mem_top;
-	trans->mem_top += size;
-	memset(p, 0, size);
-	return p;
-}
-
-static inline void check_srcu_held_too_long(struct btree_trans *trans)
-{
-	WARN(trans->srcu_held && time_after(jiffies, trans->srcu_lock_time + HZ * 10),
-	     "btree trans held srcu lock (delaying memory reclaim) for %lu seconds",
-	     (jiffies - trans->srcu_lock_time) / HZ);
-}
-
-void bch2_trans_srcu_unlock(struct btree_trans *trans)
-{
-	if (trans->srcu_held) {
-		struct bch_fs *c = trans->c;
-		struct btree_path *path;
-		unsigned i;
-
-		trans_for_each_path(trans, path, i)
-			if (path->cached && !btree_node_locked(path, 0))
-				path->l[0].b = ERR_PTR(-BCH_ERR_no_btree_node_srcu_reset);
-
-		check_srcu_held_too_long(trans);
-		srcu_read_unlock(&c->btree_trans_barrier, trans->srcu_idx);
-		trans->srcu_held = false;
-	}
-}
-
-static void bch2_trans_srcu_lock(struct btree_trans *trans)
-{
-	if (!trans->srcu_held) {
-		trans->srcu_idx = srcu_read_lock(&trans->c->btree_trans_barrier);
-		trans->srcu_lock_time	= jiffies;
-		trans->srcu_held = true;
-	}
-}
-
-/**
- * bch2_trans_begin() - reset a transaction after a interrupted attempt
- * @trans: transaction to reset
- *
- * Returns:	current restart counter, to be used with trans_was_restarted()
- *
- * While iterating over nodes or updating nodes a attempt to lock a btree node
- * may return BCH_ERR_transaction_restart when the trylock fails. When this
- * occurs bch2_trans_begin() should be called and the transaction retried.
- */
-u32 bch2_trans_begin(struct btree_trans *trans)
-{
-	struct btree_path *path;
-	unsigned i;
-	u64 now;
-
-	bch2_trans_reset_updates(trans);
-
-	trans->restart_count++;
-	trans->mem_top			= 0;
-	trans->journal_entries		= NULL;
-
-	trans_for_each_path(trans, path, i) {
-		path->should_be_locked = false;
-
-		/*
-		 * If the transaction wasn't restarted, we're presuming to be
-		 * doing something new: dont keep iterators excpt the ones that
-		 * are in use - except for the subvolumes btree:
-		 */
-		if (!trans->restarted && path->btree_id != BTREE_ID_subvolumes)
-			path->preserve = false;
-
-		/*
-		 * XXX: we probably shouldn't be doing this if the transaction
-		 * was restarted, but currently we still overflow transaction
-		 * iterators if we do that
-		 */
-		if (!path->ref && !path->preserve)
-			__bch2_path_free(trans, i);
-		else
-			path->preserve = false;
-	}
-
-	now = local_clock();
-
-	if (!IS_ENABLED(CONFIG_BCACHEFS_NO_LATENCY_ACCT) &&
-	    time_after64(now, trans->last_begin_time + 10))
-		__bch2_time_stats_update(&btree_trans_stats(trans)->duration,
-					 trans->last_begin_time, now);
-
-	if (!trans->restarted &&
-	    (need_resched() ||
-	     time_after64(now, trans->last_begin_time + BTREE_TRANS_MAX_LOCK_HOLD_TIME_NS))) {
-		drop_locks_do(trans, (cond_resched(), 0));
-		now = local_clock();
-	}
-	trans->last_begin_time = now;
-
-	if (unlikely(trans->srcu_held &&
-		     time_after(jiffies, trans->srcu_lock_time + msecs_to_jiffies(10))))
-		bch2_trans_srcu_unlock(trans);
-
-	trans->last_begin_ip = _RET_IP_;
-	if (trans->restarted) {
-		bch2_btree_path_traverse_all(trans);
-		trans->notrace_relock_fail = false;
-	}
-
-	return trans->restart_count;
-}
-
-const char *bch2_btree_transaction_fns[BCH_TRANSACTIONS_NR] = { "(unknown)" };
-
-unsigned bch2_trans_get_fn_idx(const char *fn)
-{
-	for (unsigned i = 0; i < ARRAY_SIZE(bch2_btree_transaction_fns); i++)
-		if (!bch2_btree_transaction_fns[i] ||
-		    bch2_btree_transaction_fns[i] == fn) {
-			bch2_btree_transaction_fns[i] = fn;
-			return i;
-		}
-
-	pr_warn_once("BCH_TRANSACTIONS_NR not big enough!");
-	return 0;
-}
-
-struct btree_trans *__bch2_trans_get(struct bch_fs *c, unsigned fn_idx)
-	__acquires(&c->btree_trans_barrier)
-{
-	struct btree_trans *trans;
-
-	if (IS_ENABLED(__KERNEL__)) {
-		trans = this_cpu_xchg(c->btree_trans_bufs->trans, NULL);
-		if (trans) {
-			memset(trans, 0, offsetof(struct btree_trans, list));
-			goto got_trans;
-		}
-	}
-
-	trans = mempool_alloc(&c->btree_trans_pool, GFP_NOFS);
-	memset(trans, 0, sizeof(*trans));
-	closure_init_stack(&trans->ref);
-
-	seqmutex_lock(&c->btree_trans_lock);
-	if (IS_ENABLED(CONFIG_BCACHEFS_DEBUG)) {
-		struct btree_trans *pos;
-		pid_t pid = current->pid;
-
-		trans->locking_wait.task = current;
-
-		list_for_each_entry(pos, &c->btree_trans_list, list) {
-			struct task_struct *pos_task = READ_ONCE(pos->locking_wait.task);
-			/*
-			 * We'd much prefer to be stricter here and completely
-			 * disallow multiple btree_trans in the same thread -
-			 * but the data move path calls bch2_write when we
-			 * already have a btree_trans initialized.
-			 */
-			BUG_ON(pos_task &&
-			       pid == pos_task->pid &&
-			       bch2_trans_locked(pos));
-
-			if (pos_task && pid < pos_task->pid) {
-				list_add_tail(&trans->list, &pos->list);
-				goto list_add_done;
-			}
-		}
-	}
-	list_add_tail(&trans->list, &c->btree_trans_list);
-list_add_done:
-	seqmutex_unlock(&c->btree_trans_lock);
-got_trans:
-	trans->c		= c;
-	trans->last_begin_time	= local_clock();
-	trans->fn_idx		= fn_idx;
-	trans->locking_wait.task = current;
-	trans->journal_replay_not_finished =
-		unlikely(!test_bit(JOURNAL_REPLAY_DONE, &c->journal.flags)) &&
-		atomic_inc_not_zero(&c->journal_keys.ref);
-	trans->nr_paths		= ARRAY_SIZE(trans->_paths);
-	trans->paths_allocated	= trans->_paths_allocated;
-	trans->sorted		= trans->_sorted;
-	trans->paths		= trans->_paths;
-	trans->updates		= trans->_updates;
-
-	*trans_paths_nr(trans->paths) = BTREE_ITER_INITIAL;
-
-	trans->paths_allocated[0] = 1;
-
-	if (fn_idx < BCH_TRANSACTIONS_NR) {
-		trans->fn = bch2_btree_transaction_fns[fn_idx];
-
-		struct btree_transaction_stats *s = &c->btree_transaction_stats[fn_idx];
-
-		if (s->max_mem) {
-			unsigned expected_mem_bytes = roundup_pow_of_two(s->max_mem);
-
-			trans->mem = kmalloc(expected_mem_bytes, GFP_KERNEL);
-			if (likely(trans->mem))
-				trans->mem_bytes = expected_mem_bytes;
-		}
-
-		trans->nr_paths_max = s->nr_max_paths;
-		trans->journal_entries_size = s->journal_entries_size;
-	}
-
-	trans->srcu_idx		= srcu_read_lock(&c->btree_trans_barrier);
-	trans->srcu_lock_time	= jiffies;
-	trans->srcu_held	= true;
-	return trans;
-}
-
-static void check_btree_paths_leaked(struct btree_trans *trans)
-{
-#ifdef CONFIG_BCACHEFS_DEBUG
-	struct bch_fs *c = trans->c;
-	struct btree_path *path;
-	unsigned i;
-
-	trans_for_each_path(trans, path, i)
-		if (path->ref)
-			goto leaked;
-	return;
-leaked:
-	bch_err(c, "btree paths leaked from %s!", trans->fn);
-	trans_for_each_path(trans, path, i)
-		if (path->ref)
-			printk(KERN_ERR "  btree %s %pS\n",
-			       bch2_btree_id_str(path->btree_id),
-			       (void *) path->ip_allocated);
-	/* Be noisy about this: */
-	bch2_fatal_error(c);
-#endif
-}
-
-void bch2_trans_put(struct btree_trans *trans)
-	__releases(&c->btree_trans_barrier)
-{
-	struct bch_fs *c = trans->c;
-
-	bch2_trans_unlock(trans);
-
-	trans_for_each_update(trans, i)
-		__btree_path_put(trans->paths + i->path, true);
-	trans->nr_updates	= 0;
-	trans->locking_wait.task = NULL;
-
-	check_btree_paths_leaked(trans);
-
-	if (trans->srcu_held) {
-		check_srcu_held_too_long(trans);
-		srcu_read_unlock(&c->btree_trans_barrier, trans->srcu_idx);
-	}
-
-	if (trans->fs_usage_deltas) {
-		if (trans->fs_usage_deltas->size + sizeof(trans->fs_usage_deltas) ==
-		    REPLICAS_DELTA_LIST_MAX)
-			mempool_free(trans->fs_usage_deltas,
-				     &c->replicas_delta_pool);
-		else
-			kfree(trans->fs_usage_deltas);
-	}
-
-	if (unlikely(trans->journal_replay_not_finished))
-		bch2_journal_keys_put(c);
-
-	unsigned long *paths_allocated = trans->paths_allocated;
-	trans->paths_allocated	= NULL;
-	trans->paths		= NULL;
-
-	if (paths_allocated != trans->_paths_allocated)
-		kfree_rcu_mightsleep(paths_allocated);
-
-	if (trans->mem_bytes == BTREE_TRANS_MEM_MAX)
-		mempool_free(trans->mem, &c->btree_trans_mem_pool);
-	else
-		kfree(trans->mem);
-
-	/* Userspace doesn't have a real percpu implementation: */
-	if (IS_ENABLED(__KERNEL__))
-		trans = this_cpu_xchg(c->btree_trans_bufs->trans, trans);
-
-	if (trans) {
-		closure_sync(&trans->ref);
-
-		seqmutex_lock(&c->btree_trans_lock);
-		list_del(&trans->list);
-		seqmutex_unlock(&c->btree_trans_lock);
-
-		mempool_free(trans, &c->btree_trans_pool);
-	}
-}
-
-static void __maybe_unused
-bch2_btree_bkey_cached_common_to_text(struct printbuf *out,
-				      struct btree_bkey_cached_common *b)
-{
-	struct six_lock_count c = six_lock_counts(&b->lock);
-	struct task_struct *owner;
-	pid_t pid;
-
-	rcu_read_lock();
-	owner = READ_ONCE(b->lock.owner);
-	pid = owner ? owner->pid : 0;
-	rcu_read_unlock();
-
-	prt_tab(out);
-	prt_printf(out, "%px %c l=%u %s:", b, b->cached ? 'c' : 'b',
-		   b->level, bch2_btree_id_str(b->btree_id));
-	bch2_bpos_to_text(out, btree_node_pos(b));
-
-	prt_tab(out);
-	prt_printf(out, " locks %u:%u:%u held by pid %u",
-		   c.n[0], c.n[1], c.n[2], pid);
-}
-
-void bch2_btree_trans_to_text(struct printbuf *out, struct btree_trans *trans)
-{
-	struct btree_bkey_cached_common *b;
-	static char lock_types[] = { 'r', 'i', 'w' };
-	struct task_struct *task = READ_ONCE(trans->locking_wait.task);
-	unsigned l, idx;
-
-	/* before rcu_read_lock(): */
-	bch2_printbuf_make_room(out, 4096);
-
-	if (!out->nr_tabstops) {
-		printbuf_tabstop_push(out, 16);
-		printbuf_tabstop_push(out, 32);
-	}
-
-	prt_printf(out, "%i %s\n", task ? task->pid : 0, trans->fn);
-
-	/* trans->paths is rcu protected vs. freeing */
-	rcu_read_lock();
-	out->atomic++;
-
-	struct btree_path *paths = rcu_dereference(trans->paths);
-	if (!paths)
-		goto out;
-
-	unsigned long *paths_allocated = trans_paths_allocated(paths);
-
-	trans_for_each_path_idx_from(paths_allocated, *trans_paths_nr(paths), idx, 1) {
-		struct btree_path *path = paths + idx;
-		if (!path->nodes_locked)
-			continue;
-
-		prt_printf(out, "  path %u %c l=%u %s:",
-		       idx,
-		       path->cached ? 'c' : 'b',
-		       path->level,
-		       bch2_btree_id_str(path->btree_id));
-		bch2_bpos_to_text(out, path->pos);
-		prt_newline(out);
-
-		for (l = 0; l < BTREE_MAX_DEPTH; l++) {
-			if (btree_node_locked(path, l) &&
-			    !IS_ERR_OR_NULL(b = (void *) READ_ONCE(path->l[l].b))) {
-				prt_printf(out, "    %c l=%u ",
-					   lock_types[btree_node_locked_type(path, l)], l);
-				bch2_btree_bkey_cached_common_to_text(out, b);
-				prt_newline(out);
-			}
-		}
-	}
-
-	b = READ_ONCE(trans->locking);
-	if (b) {
-		prt_printf(out, "  blocked for %lluus on",
-			   div_u64(local_clock() - trans->locking_wait.start_time,
-				   1000));
-		prt_newline(out);
-		prt_printf(out, "    %c", lock_types[trans->locking_wait.lock_want]);
-		bch2_btree_bkey_cached_common_to_text(out, b);
-		prt_newline(out);
-	}
-out:
-	--out->atomic;
-	rcu_read_unlock();
-}
-
-void bch2_fs_btree_iter_exit(struct bch_fs *c)
-{
-	struct btree_transaction_stats *s;
-	struct btree_trans *trans;
-	int cpu;
-
-	if (c->btree_trans_bufs)
-		for_each_possible_cpu(cpu) {
-			struct btree_trans *trans =
-				per_cpu_ptr(c->btree_trans_bufs, cpu)->trans;
-
-			if (trans) {
-				closure_sync(&trans->ref);
-
-				seqmutex_lock(&c->btree_trans_lock);
-				list_del(&trans->list);
-				seqmutex_unlock(&c->btree_trans_lock);
-			}
-			kfree(trans);
-		}
-	free_percpu(c->btree_trans_bufs);
-
-	trans = list_first_entry_or_null(&c->btree_trans_list, struct btree_trans, list);
-	if (trans)
-		panic("%s leaked btree_trans\n", trans->fn);
-
-	for (s = c->btree_transaction_stats;
-	     s < c->btree_transaction_stats + ARRAY_SIZE(c->btree_transaction_stats);
-	     s++) {
-		kfree(s->max_paths_text);
-		bch2_time_stats_exit(&s->lock_hold_times);
-	}
-
-	if (c->btree_trans_barrier_initialized)
-		cleanup_srcu_struct(&c->btree_trans_barrier);
-	mempool_exit(&c->btree_trans_mem_pool);
-	mempool_exit(&c->btree_trans_pool);
-}
-
-void bch2_fs_btree_iter_init_early(struct bch_fs *c)
-{
-	struct btree_transaction_stats *s;
-
-	for (s = c->btree_transaction_stats;
-	     s < c->btree_transaction_stats + ARRAY_SIZE(c->btree_transaction_stats);
-	     s++) {
-		bch2_time_stats_init(&s->duration);
-		bch2_time_stats_init(&s->lock_hold_times);
-		mutex_init(&s->lock);
-	}
-
-	INIT_LIST_HEAD(&c->btree_trans_list);
-	seqmutex_init(&c->btree_trans_lock);
-}
-
-int bch2_fs_btree_iter_init(struct bch_fs *c)
-{
-	int ret;
-
-	c->btree_trans_bufs = alloc_percpu(struct btree_trans_buf);
-	if (!c->btree_trans_bufs)
-		return -ENOMEM;
-
-	ret   = mempool_init_kmalloc_pool(&c->btree_trans_pool, 1,
-					  sizeof(struct btree_trans)) ?:
-		mempool_init_kmalloc_pool(&c->btree_trans_mem_pool, 1,
-					  BTREE_TRANS_MEM_MAX) ?:
-		init_srcu_struct(&c->btree_trans_barrier);
-	if (!ret)
-		c->btree_trans_barrier_initialized = true;
-	return ret;
-}