1	// SPDX-License-Identifier: GPL-2.0
2
3	#include "bcachefs.h"
4	#include "bkey_methods.h"
5	#include "bkey_buf.h"
6	#include "btree_cache.h"
7	#include "btree_iter.h"
8	#include "btree_journal_iter.h"
9	#include "btree_key_cache.h"
10	#include "btree_locking.h"
11	#include "btree_update.h"
12	#include "debug.h"
13	#include "error.h"
14	#include "extents.h"
15	#include "journal.h"
16	#include "journal_io.h"
17	#include "replicas.h"
18	#include "snapshot.h"
19	#include "trace.h"
20
21	#include <linux/random.h>
22	#include <linux/prefetch.h>
23
24	static inline void btree_path_list_remove(struct btree_trans *, struct btree_path *);
25	static inline void btree_path_list_add(struct btree_trans *,
26	btree_path_idx_t, btree_path_idx_t);
27
28	static inline unsigned long btree_iter_ip_allocated(struct btree_iter *iter)
29	{
30	#ifdef TRACK_PATH_ALLOCATED
31	return iter->ip_allocated;
32	#else
33	return 0;
34	#endif
35	}
36
37	static btree_path_idx_t btree_path_alloc(struct btree_trans *, btree_path_idx_t);
38	static void bch2_trans_srcu_lock(struct btree_trans *);
39
40	static inline int __btree_path_cmp(const struct btree_path *l,
41	enum btree_id r_btree_id,
42	bool r_cached,
43	struct bpos r_pos,
44	unsigned r_level)
45	{
46	/*
47	* Must match lock ordering as defined by __bch2_btree_node_lock:
48	*/
49	return cmp_int(l->btree_id, r_btree_id) ?:
50	cmp_int((int) l->cached, (int) r_cached) ?:
51	bpos_cmp(l: l->pos, r: r_pos) ?:
52	-cmp_int(l->level, r_level);
53	}
54
55	static inline int btree_path_cmp(const struct btree_path *l,
56	const struct btree_path *r)
57	{
58	return __btree_path_cmp(l, r_btree_id: r->btree_id, r_cached: r->cached, r_pos: r->pos, r_level: r->level);
59	}
60
61	static inline struct bpos bkey_successor(struct btree_iter *iter, struct bpos p)
62	{
63	/* Are we iterating over keys in all snapshots? */
64	if (iter->flags & BTREE_ITER_ALL_SNAPSHOTS) {
65	p = bpos_successor(p);
66	} else {
67	p = bpos_nosnap_successor(p);
68	p.snapshot = iter->snapshot;
69	}
70
71	return p;
72	}
73
74	static inline struct bpos bkey_predecessor(struct btree_iter *iter, struct bpos p)
75	{
76	/* Are we iterating over keys in all snapshots? */
77	if (iter->flags & BTREE_ITER_ALL_SNAPSHOTS) {
78	p = bpos_predecessor(p);
79	} else {
80	p = bpos_nosnap_predecessor(p);
81	p.snapshot = iter->snapshot;
82	}
83
84	return p;
85	}
86
87	static inline struct bpos btree_iter_search_key(struct btree_iter *iter)
88	{
89	struct bpos pos = iter->pos;
90
91	if ((iter->flags & BTREE_ITER_IS_EXTENTS) &&
92	!bkey_eq(l: pos, POS_MAX))
93	pos = bkey_successor(iter, p: pos);
94	return pos;
95	}
96
97	static inline bool btree_path_pos_before_node(struct btree_path *path,
98	struct btree *b)
99	{
100	return bpos_lt(l: path->pos, r: b->data->min_key);
101	}
102
103	static inline bool btree_path_pos_after_node(struct btree_path *path,
104	struct btree *b)
105	{
106	return bpos_gt(l: path->pos, r: b->key.k.p);
107	}
108
109	static inline bool btree_path_pos_in_node(struct btree_path *path,
110	struct btree *b)
111	{
112	return path->btree_id == b->c.btree_id &&
113	!btree_path_pos_before_node(path, b) &&
114	!btree_path_pos_after_node(path, b);
115	}
116
117	/* Btree iterator: */
118
119	#ifdef CONFIG_BCACHEFS_DEBUG
120
121	static void bch2_btree_path_verify_cached(struct btree_trans *trans,
122	struct btree_path *path)
123	{
124	struct bkey_cached *ck;
125	bool locked = btree_node_locked(path, level: 0);
126
127	if (!bch2_btree_node_relock(trans, path, level: 0))
128	return;
129
130	ck = (void *) path->l[0].b;
131	BUG_ON(ck->key.btree_id != path->btree_id ||
132	!bkey_eq(ck->key.pos, path->pos));
133
134	if (!locked)
135	btree_node_unlock(trans, path, level: 0);
136	}
137
138	static void bch2_btree_path_verify_level(struct btree_trans *trans,
139	struct btree_path *path, unsigned level)
140	{
141	struct btree_path_level *l;
142	struct btree_node_iter tmp;
143	bool locked;
144	struct bkey_packed *p, *k;
145	struct printbuf buf1 = PRINTBUF;
146	struct printbuf buf2 = PRINTBUF;
147	struct printbuf buf3 = PRINTBUF;
148	const char *msg;
149
150	if (!bch2_debug_check_iterators)
151	return;
152
153	l = &path->l[level];
154	tmp = l->iter;
155	locked = btree_node_locked(path, level);
156
157	if (path->cached) {
158	if (!level)
159	bch2_btree_path_verify_cached(trans, path);
160	return;
161	}
162
163	if (!btree_path_node(path, level))
164	return;
165
166	if (!bch2_btree_node_relock_notrace(trans, path, level))
167	return;
168
169	BUG_ON(!btree_path_pos_in_node(path, l->b));
170
171	bch2_btree_node_iter_verify(&l->iter, l->b);
172
173	/*
174	* For interior nodes, the iterator will have skipped past deleted keys:
175	*/
176	p = level
177	? bch2_btree_node_iter_prev(&tmp, l->b)
178	: bch2_btree_node_iter_prev_all(&tmp, l->b);
179	k = bch2_btree_node_iter_peek_all(iter: &l->iter, b: l->b);
180
181	if (p && bkey_iter_pos_cmp(b: l->b, l: p, r: &path->pos) >= 0) {
182	msg = "before";
183	goto err;
184	}
185
186	if (k && bkey_iter_pos_cmp(b: l->b, l: k, r: &path->pos) < 0) {
187	msg = "after";
188	goto err;
189	}
190
191	if (!locked)
192	btree_node_unlock(trans, path, level);
193	return;
194	err:
195	bch2_bpos_to_text(&buf1, path->pos);
196
197	if (p) {
198	struct bkey uk = bkey_unpack_key(b: l->b, src: p);
199
200	bch2_bkey_to_text(&buf2, &uk);
201	} else {
202	prt_printf(&buf2, "(none)");
203	}
204
205	if (k) {
206	struct bkey uk = bkey_unpack_key(b: l->b, src: k);
207
208	bch2_bkey_to_text(&buf3, &uk);
209	} else {
210	prt_printf(&buf3, "(none)");
211	}
212
213	panic(fmt: "path should be %s key at level %u:\n"
214	"path pos %s\n"
215	"prev key %s\n"
216	"cur key %s\n",
217	msg, level, buf1.buf, buf2.buf, buf3.buf);
218	}
219
220	static void bch2_btree_path_verify(struct btree_trans *trans,
221	struct btree_path *path)
222	{
223	struct bch_fs *c = trans->c;
224	unsigned i;
225
226	EBUG_ON(path->btree_id >= BTREE_ID_NR);
227
228	for (i = 0; i < (!path->cached ? BTREE_MAX_DEPTH : 1); i++) {
229	if (!path->l[i].b) {
230	BUG_ON(!path->cached &&
231	bch2_btree_id_root(c, path->btree_id)->b->c.level > i);
232	break;
233	}
234
235	bch2_btree_path_verify_level(trans, path, level: i);
236	}
237
238	bch2_btree_path_verify_locks(path);
239	}
240
241	void bch2_trans_verify_paths(struct btree_trans *trans)
242	{
243	struct btree_path *path;
244	unsigned iter;
245
246	trans_for_each_path(trans, path, iter)
247	bch2_btree_path_verify(trans, path);
248	}
249
250	static void bch2_btree_iter_verify(struct btree_iter *iter)
251	{
252	struct btree_trans *trans = iter->trans;
253
254	BUG_ON(iter->btree_id >= BTREE_ID_NR);
255
256	BUG_ON(!!(iter->flags & BTREE_ITER_CACHED) != btree_iter_path(trans, iter)->cached);
257
258	BUG_ON((iter->flags & BTREE_ITER_IS_EXTENTS) &&
259	(iter->flags & BTREE_ITER_ALL_SNAPSHOTS));
260
261	BUG_ON(!(iter->flags & __BTREE_ITER_ALL_SNAPSHOTS) &&
262	(iter->flags & BTREE_ITER_ALL_SNAPSHOTS) &&
263	!btree_type_has_snapshot_field(iter->btree_id));
264
265	if (iter->update_path)
266	bch2_btree_path_verify(trans, path: &trans->paths[iter->update_path]);
267	bch2_btree_path_verify(trans, path: btree_iter_path(trans, iter));
268	}
269
270	static void bch2_btree_iter_verify_entry_exit(struct btree_iter *iter)
271	{
272	BUG_ON((iter->flags & BTREE_ITER_FILTER_SNAPSHOTS) &&
273	!iter->pos.snapshot);
274
275	BUG_ON(!(iter->flags & BTREE_ITER_ALL_SNAPSHOTS) &&
276	iter->pos.snapshot != iter->snapshot);
277
278	BUG_ON(bkey_lt(iter->pos, bkey_start_pos(&iter->k)) ||
279	bkey_gt(iter->pos, iter->k.p));
280	}
281
282	static int bch2_btree_iter_verify_ret(struct btree_iter *iter, struct bkey_s_c k)
283	{
284	struct btree_trans *trans = iter->trans;
285	struct btree_iter copy;
286	struct bkey_s_c prev;
287	int ret = 0;
288
289	if (!bch2_debug_check_iterators)
290	return 0;
291
292	if (!(iter->flags & BTREE_ITER_FILTER_SNAPSHOTS))
293	return 0;
294
295	if (bkey_err(k) || !k.k)
296	return 0;
297
298	BUG_ON(!bch2_snapshot_is_ancestor(trans->c,
299	iter->snapshot,
300	k.k->p.snapshot));
301
302	bch2_trans_iter_init(trans, iter: &copy, btree_id: iter->btree_id, pos: iter->pos,
303	flags: BTREE_ITER_NOPRESERVE|
304	BTREE_ITER_ALL_SNAPSHOTS);
305	prev = bch2_btree_iter_prev(&copy);
306	if (!prev.k)
307	goto out;
308
309	ret = bkey_err(prev);
310	if (ret)
311	goto out;
312
313	if (bkey_eq(l: prev.k->p, r: k.k->p) &&
314	bch2_snapshot_is_ancestor(c: trans->c, id: iter->snapshot,
315	ancestor: prev.k->p.snapshot) > 0) {
316	struct printbuf buf1 = PRINTBUF, buf2 = PRINTBUF;
317
318	bch2_bkey_to_text(&buf1, k.k);
319	bch2_bkey_to_text(&buf2, prev.k);
320
321	panic(fmt: "iter snap %u\n"
322	"k %s\n"
323	"prev %s\n",
324	iter->snapshot,
325	buf1.buf, buf2.buf);
326	}
327	out:
328	bch2_trans_iter_exit(trans, &copy);
329	return ret;
330	}
331
332	void bch2_assert_pos_locked(struct btree_trans *trans, enum btree_id id,
333	struct bpos pos, bool key_cache)
334	{
335	struct btree_path *path;
336	struct trans_for_each_path_inorder_iter iter;
337	struct printbuf buf = PRINTBUF;
338
339	btree_trans_sort_paths(trans);
340
341	trans_for_each_path_inorder(trans, path, iter) {
342	int cmp = cmp_int(path->btree_id, id) ?:
343	cmp_int(path->cached, key_cache);
344
345	if (cmp > 0)
346	break;
347	if (cmp < 0)
348	continue;
349
350	if (!btree_node_locked(path, 0) ||
351	!path->should_be_locked)
352	continue;
353
354	if (!key_cache) {
355	if (bkey_ge(pos, path->l[0].b->data->min_key) &&
356	bkey_le(pos, path->l[0].b->key.k.p))
357	return;
358	} else {
359	if (bkey_eq(pos, path->pos))
360	return;
361	}
362	}
363
364	bch2_dump_trans_paths_updates(trans);
365	bch2_bpos_to_text(&buf, pos);
366
367	panic("not locked: %s %s%s\n",
368	bch2_btree_id_str(id), buf.buf,
369	key_cache ? " cached" : "");
370	}
371
372	#else
373
374	static inline void bch2_btree_path_verify_level(struct btree_trans *trans,
375	struct btree_path *path, unsigned l) {}
376	static inline void bch2_btree_path_verify(struct btree_trans *trans,
377	struct btree_path *path) {}
378	static inline void bch2_btree_iter_verify(struct btree_iter *iter) {}
379	static inline void bch2_btree_iter_verify_entry_exit(struct btree_iter *iter) {}
380	static inline int bch2_btree_iter_verify_ret(struct btree_iter *iter, struct bkey_s_c k) { return 0; }
381
382	#endif
383
384	/* Btree path: fixups after btree updates */
385
386	static void btree_node_iter_set_set_pos(struct btree_node_iter *iter,
387	struct btree *b,
388	struct bset_tree *t,
389	struct bkey_packed *k)
390	{
391	struct btree_node_iter_set *set;
392
393	btree_node_iter_for_each(iter, set)
394	if (set->end == t->end_offset) {
395	set->k = __btree_node_key_to_offset(b, k);
396	bch2_btree_node_iter_sort(iter, b);
397	return;
398	}
399
400	bch2_btree_node_iter_push(iter, b, k, btree_bkey_last(b, t));
401	}
402
403	static void __bch2_btree_path_fix_key_modified(struct btree_path *path,
404	struct btree *b,
405	struct bkey_packed *where)
406	{
407	struct btree_path_level *l = &path->l[b->c.level];
408
409	if (where != bch2_btree_node_iter_peek_all(iter: &l->iter, b: l->b))
410	return;
411
412	if (bkey_iter_pos_cmp(b: l->b, l: where, r: &path->pos) < 0)
413	bch2_btree_node_iter_advance(&l->iter, l->b);
414	}
415
416	void bch2_btree_path_fix_key_modified(struct btree_trans *trans,
417	struct btree *b,
418	struct bkey_packed *where)
419	{
420	struct btree_path *path;
421	unsigned i;
422
423	trans_for_each_path_with_node(trans, b, path, i) {
424	__bch2_btree_path_fix_key_modified(path, b, where);
425	bch2_btree_path_verify_level(trans, path, level: b->c.level);
426	}
427	}
428
429	static void __bch2_btree_node_iter_fix(struct btree_path *path,
430	struct btree *b,
431	struct btree_node_iter *node_iter,
432	struct bset_tree *t,
433	struct bkey_packed *where,
434	unsigned clobber_u64s,
435	unsigned new_u64s)
436	{
437	const struct bkey_packed *end = btree_bkey_last(b, t);
438	struct btree_node_iter_set *set;
439	unsigned offset = __btree_node_key_to_offset(b, k: where);
440	int shift = new_u64s - clobber_u64s;
441	unsigned old_end = t->end_offset - shift;
442	unsigned orig_iter_pos = node_iter->data[0].k;
443	bool iter_current_key_modified =
444	orig_iter_pos >= offset &&
445	orig_iter_pos <= offset + clobber_u64s;
446
447	btree_node_iter_for_each(node_iter, set)
448	if (set->end == old_end)
449	goto found;
450
451	/* didn't find the bset in the iterator - might have to readd it: */
452	if (new_u64s &&
453	bkey_iter_pos_cmp(b, l: where, r: &path->pos) >= 0) {
454	bch2_btree_node_iter_push(node_iter, b, where, end);
455	goto fixup_done;
456	} else {
457	/* Iterator is after key that changed */
458	return;
459	}
460	found:
461	set->end = t->end_offset;
462
463	/* Iterator hasn't gotten to the key that changed yet: */
464	if (set->k < offset)
465	return;
466
467	if (new_u64s &&
468	bkey_iter_pos_cmp(b, l: where, r: &path->pos) >= 0) {
469	set->k = offset;
470	} else if (set->k < offset + clobber_u64s) {
471	set->k = offset + new_u64s;
472	if (set->k == set->end)
473	bch2_btree_node_iter_set_drop(node_iter, set);
474	} else {
475	/* Iterator is after key that changed */
476	set->k = (int) set->k + shift;
477	return;
478	}
479
480	bch2_btree_node_iter_sort(node_iter, b);
481	fixup_done:
482	if (node_iter->data[0].k != orig_iter_pos)
483	iter_current_key_modified = true;
484
485	/*
486	* When a new key is added, and the node iterator now points to that
487	* key, the iterator might have skipped past deleted keys that should
488	* come after the key the iterator now points to. We have to rewind to
489	* before those deleted keys - otherwise
490	* bch2_btree_node_iter_prev_all() breaks:
491	*/
492	if (!bch2_btree_node_iter_end(iter: node_iter) &&
493	iter_current_key_modified &&
494	b->c.level) {
495	struct bkey_packed *k, *k2, *p;
496
497	k = bch2_btree_node_iter_peek_all(iter: node_iter, b);
498
499	for_each_bset(b, t) {
500	bool set_pos = false;
501
502	if (node_iter->data[0].end == t->end_offset)
503	continue;
504
505	k2 = bch2_btree_node_iter_bset_pos(node_iter, b, t);
506
507	while ((p = bch2_bkey_prev_all(b, t, k: k2)) &&
508	bkey_iter_cmp(b, l: k, r: p) < 0) {
509	k2 = p;
510	set_pos = true;
511	}
512
513	if (set_pos)
514	btree_node_iter_set_set_pos(iter: node_iter,
515	b, t, k: k2);
516	}
517	}
518	}
519
520	void bch2_btree_node_iter_fix(struct btree_trans *trans,
521	struct btree_path *path,
522	struct btree *b,
523	struct btree_node_iter *node_iter,
524	struct bkey_packed *where,
525	unsigned clobber_u64s,
526	unsigned new_u64s)
527	{
528	struct bset_tree *t = bch2_bkey_to_bset_inlined(b, k: where);
529	struct btree_path *linked;
530	unsigned i;
531
532	if (node_iter != &path->l[b->c.level].iter) {
533	__bch2_btree_node_iter_fix(path, b, node_iter, t,
534	where, clobber_u64s, new_u64s);
535
536	if (bch2_debug_check_iterators)
537	bch2_btree_node_iter_verify(node_iter, b);
538	}
539
540	trans_for_each_path_with_node(trans, b, linked, i) {
541	__bch2_btree_node_iter_fix(path: linked, b,
542	node_iter: &linked->l[b->c.level].iter, t,
543	where, clobber_u64s, new_u64s);
544	bch2_btree_path_verify_level(trans, path: linked, level: b->c.level);
545	}
546	}
547
548	/* Btree path level: pointer to a particular btree node and node iter */
549
550	static inline struct bkey_s_c __btree_iter_unpack(struct bch_fs *c,
551	struct btree_path_level *l,
552	struct bkey *u,
553	struct bkey_packed *k)
554	{
555	if (unlikely(!k)) {
556	/*
557	* signal to bch2_btree_iter_peek_slot() that we're currently at
558	* a hole
559	*/
560	u->type = KEY_TYPE_deleted;
561	return bkey_s_c_null;
562	}
563
564	return bkey_disassemble(b: l->b, k, u);
565	}
566
567	static inline struct bkey_s_c btree_path_level_peek_all(struct bch_fs *c,
568	struct btree_path_level *l,
569	struct bkey *u)
570	{
571	return __btree_iter_unpack(c, l, u,
572	k: bch2_btree_node_iter_peek_all(iter: &l->iter, b: l->b));
573	}
574
575	static inline struct bkey_s_c btree_path_level_peek(struct btree_trans *trans,
576	struct btree_path *path,
577	struct btree_path_level *l,
578	struct bkey *u)
579	{
580	struct bkey_s_c k = __btree_iter_unpack(c: trans->c, l, u,
581	k: bch2_btree_node_iter_peek(iter: &l->iter, b: l->b));
582
583	path->pos = k.k ? k.k->p : l->b->key.k.p;
584	trans->paths_sorted = false;
585	bch2_btree_path_verify_level(trans, path, level: l - path->l);
586	return k;
587	}
588
589	static inline struct bkey_s_c btree_path_level_prev(struct btree_trans *trans,
590	struct btree_path *path,
591	struct btree_path_level *l,
592	struct bkey *u)
593	{
594	struct bkey_s_c k = __btree_iter_unpack(c: trans->c, l, u,
595	k: bch2_btree_node_iter_prev(&l->iter, l->b));
596
597	path->pos = k.k ? k.k->p : l->b->data->min_key;
598	trans->paths_sorted = false;
599	bch2_btree_path_verify_level(trans, path, level: l - path->l);
600	return k;
601	}
602
603	static inline bool btree_path_advance_to_pos(struct btree_path *path,
604	struct btree_path_level *l,
605	int max_advance)
606	{
607	struct bkey_packed *k;
608	int nr_advanced = 0;
609
610	while ((k = bch2_btree_node_iter_peek_all(iter: &l->iter, b: l->b)) &&
611	bkey_iter_pos_cmp(b: l->b, l: k, r: &path->pos) < 0) {
612	if (max_advance > 0 && nr_advanced >= max_advance)
613	return false;
614
615	bch2_btree_node_iter_advance(&l->iter, l->b);
616	nr_advanced++;
617	}
618
619	return true;
620	}
621
622	static inline void __btree_path_level_init(struct btree_path *path,
623	unsigned level)
624	{
625	struct btree_path_level *l = &path->l[level];
626
627	bch2_btree_node_iter_init(&l->iter, l->b, &path->pos);
628
629	/*
630	* Iterators to interior nodes should always be pointed at the first non
631	* whiteout:
632	*/
633	if (level)
634	bch2_btree_node_iter_peek(iter: &l->iter, b: l->b);
635	}
636
637	void bch2_btree_path_level_init(struct btree_trans *trans,
638	struct btree_path *path,
639	struct btree *b)
640	{
641	BUG_ON(path->cached);
642
643	EBUG_ON(!btree_path_pos_in_node(path, b));
644
645	path->l[b->c.level].lock_seq = six_lock_seq(lock: &b->c.lock);
646	path->l[b->c.level].b = b;
647	__btree_path_level_init(path, level: b->c.level);
648	}
649
650	/* Btree path: fixups after btree node updates: */
651
652	static void bch2_trans_revalidate_updates_in_node(struct btree_trans *trans, struct btree *b)
653	{
654	struct bch_fs *c = trans->c;
655
656	trans_for_each_update(trans, i)
657	if (!i->cached &&
658	i->level == b->c.level &&
659	i->btree_id == b->c.btree_id &&
660	bpos_cmp(l: i->k->k.p, r: b->data->min_key) >= 0 &&
661	bpos_cmp(l: i->k->k.p, r: b->data->max_key) <= 0) {
662	i->old_v = bch2_btree_path_peek_slot(trans->paths + i->path, &i->old_k).v;
663
664	if (unlikely(trans->journal_replay_not_finished)) {
665	struct bkey_i *j_k =
666	bch2_journal_keys_peek_slot(c, i->btree_id, i->level,
667	i->k->k.p);
668
669	if (j_k) {
670	i->old_k = j_k->k;
671	i->old_v = &j_k->v;
672	}
673	}
674	}
675	}
676
677	/*
678	* A btree node is being replaced - update the iterator to point to the new
679	* node:
680	*/
681	void bch2_trans_node_add(struct btree_trans *trans,
682	struct btree_path *path,
683	struct btree *b)
684	{
685	struct btree_path *prev;
686
687	BUG_ON(!btree_path_pos_in_node(path, b));
688
689	while ((prev = prev_btree_path(trans, path)) &&
690	btree_path_pos_in_node(path: prev, b))
691	path = prev;
692
693	for (;
694	path && btree_path_pos_in_node(path, b);
695	path = next_btree_path(trans, path))
696	if (path->uptodate == BTREE_ITER_UPTODATE && !path->cached) {
697	enum btree_node_locked_type t =
698	btree_lock_want(path, level: b->c.level);
699
700	if (t != BTREE_NODE_UNLOCKED) {
701	btree_node_unlock(trans, path, level: b->c.level);
702	six_lock_increment(&b->c.lock, (enum six_lock_type) t);
703	mark_btree_node_locked(trans, path, level: b->c.level, type: t);
704	}
705
706	bch2_btree_path_level_init(trans, path, b);
707	}
708
709	bch2_trans_revalidate_updates_in_node(trans, b);
710	}
711
712	/*
713	* A btree node has been modified in such a way as to invalidate iterators - fix
714	* them:
715	*/
716	void bch2_trans_node_reinit_iter(struct btree_trans *trans, struct btree *b)
717	{
718	struct btree_path *path;
719	unsigned i;
720
721	trans_for_each_path_with_node(trans, b, path, i)
722	__btree_path_level_init(path, level: b->c.level);
723
724	bch2_trans_revalidate_updates_in_node(trans, b);
725	}
726
727	/* Btree path: traverse, set_pos: */
728
729	static inline int btree_path_lock_root(struct btree_trans *trans,
730	struct btree_path *path,
731	unsigned depth_want,
732	unsigned long trace_ip)
733	{
734	struct bch_fs *c = trans->c;
735	struct btree *b, **rootp = &bch2_btree_id_root(c, id: path->btree_id)->b;
736	enum six_lock_type lock_type;
737	unsigned i;
738	int ret;
739
740	EBUG_ON(path->nodes_locked);
741
742	while (1) {
743	b = READ_ONCE(*rootp);
744	path->level = READ_ONCE(b->c.level);
745
746	if (unlikely(path->level < depth_want)) {
747	/*
748	* the root is at a lower depth than the depth we want:
749	* got to the end of the btree, or we're walking nodes
750	* greater than some depth and there are no nodes >=
751	* that depth
752	*/
753	path->level = depth_want;
754	for (i = path->level; i < BTREE_MAX_DEPTH; i++)
755	path->l[i].b = NULL;
756	return 1;
757	}
758
759	lock_type = __btree_lock_want(path, level: path->level);
760	ret = btree_node_lock(trans, path, b: &b->c,
761	level: path->level, type: lock_type, ip: trace_ip);
762	if (unlikely(ret)) {
763	if (bch2_err_matches(ret, BCH_ERR_lock_fail_root_changed))
764	continue;
765	if (bch2_err_matches(ret, BCH_ERR_transaction_restart))
766	return ret;
767	BUG();
768	}
769
770	if (likely(b == READ_ONCE(*rootp) &&
771	b->c.level == path->level &&
772	!race_fault())) {
773	for (i = 0; i < path->level; i++)
774	path->l[i].b = ERR_PTR(error: -BCH_ERR_no_btree_node_lock_root);
775	path->l[path->level].b = b;
776	for (i = path->level + 1; i < BTREE_MAX_DEPTH; i++)
777	path->l[i].b = NULL;
778
779	mark_btree_node_locked(trans, path, level: path->level,
780	type: (enum btree_node_locked_type) lock_type);
781	bch2_btree_path_level_init(trans, path, b);
782	return 0;
783	}
784
785	six_unlock_type(lock: &b->c.lock, type: lock_type);
786	}
787	}
788
789	noinline
790	static int btree_path_prefetch(struct btree_trans *trans, struct btree_path *path)
791	{
792	struct bch_fs *c = trans->c;
793	struct btree_path_level *l = path_l(path);
794	struct btree_node_iter node_iter = l->iter;
795	struct bkey_packed *k;
796	struct bkey_buf tmp;
797	unsigned nr = test_bit(BCH_FS_started, &c->flags)
798	? (path->level > 1 ? 0 : 2)
799	: (path->level > 1 ? 1 : 16);
800	bool was_locked = btree_node_locked(path, level: path->level);
801	int ret = 0;
802
803	bch2_bkey_buf_init(s: &tmp);
804
805	while (nr-- && !ret) {
806	if (!bch2_btree_node_relock(trans, path, level: path->level))
807	break;
808
809	bch2_btree_node_iter_advance(&node_iter, l->b);
810	k = bch2_btree_node_iter_peek(iter: &node_iter, b: l->b);
811	if (!k)
812	break;
813
814	bch2_bkey_buf_unpack(s: &tmp, c, b: l->b, src: k);
815	ret = bch2_btree_node_prefetch(trans, path, tmp.k, path->btree_id,
816	path->level - 1);
817	}
818
819	if (!was_locked)
820	btree_node_unlock(trans, path, level: path->level);
821
822	bch2_bkey_buf_exit(s: &tmp, c);
823	return ret;
824	}
825
826	static int btree_path_prefetch_j(struct btree_trans *trans, struct btree_path *path,
827	struct btree_and_journal_iter *jiter)
828	{
829	struct bch_fs *c = trans->c;
830	struct bkey_s_c k;
831	struct bkey_buf tmp;
832	unsigned nr = test_bit(BCH_FS_started, &c->flags)
833	? (path->level > 1 ? 0 : 2)
834	: (path->level > 1 ? 1 : 16);
835	bool was_locked = btree_node_locked(path, level: path->level);
836	int ret = 0;
837
838	bch2_bkey_buf_init(s: &tmp);
839
840	while (nr-- && !ret) {
841	if (!bch2_btree_node_relock(trans, path, level: path->level))
842	break;
843
844	bch2_btree_and_journal_iter_advance(jiter);
845	k = bch2_btree_and_journal_iter_peek(jiter);
846	if (!k.k)
847	break;
848
849	bch2_bkey_buf_reassemble(s: &tmp, c, k);
850	ret = bch2_btree_node_prefetch(trans, path, tmp.k, path->btree_id,
851	path->level - 1);
852	}
853
854	if (!was_locked)
855	btree_node_unlock(trans, path, level: path->level);
856
857	bch2_bkey_buf_exit(s: &tmp, c);
858	return ret;
859	}
860
861	static noinline void btree_node_mem_ptr_set(struct btree_trans *trans,
862	struct btree_path *path,
863	unsigned plevel, struct btree *b)
864	{
865	struct btree_path_level *l = &path->l[plevel];
866	bool locked = btree_node_locked(path, level: plevel);
867	struct bkey_packed *k;
868	struct bch_btree_ptr_v2 *bp;
869
870	if (!bch2_btree_node_relock(trans, path, level: plevel))
871	return;
872
873	k = bch2_btree_node_iter_peek_all(iter: &l->iter, b: l->b);
874	BUG_ON(k->type != KEY_TYPE_btree_ptr_v2);
875
876	bp = (void *) bkeyp_val(&l->b->format, k);
877	bp->mem_ptr = (unsigned long)b;
878
879	if (!locked)
880	btree_node_unlock(trans, path, level: plevel);
881	}
882
883	static noinline int btree_node_iter_and_journal_peek(struct btree_trans *trans,
884	struct btree_path *path,
885	unsigned flags,
886	struct bkey_buf *out)
887	{
888	struct bch_fs *c = trans->c;
889	struct btree_path_level *l = path_l(path);
890	struct btree_and_journal_iter jiter;
891	struct bkey_s_c k;
892	int ret = 0;
893
894	__bch2_btree_and_journal_iter_init_node_iter(trans, &jiter, l->b, l->iter, path->pos);
895
896	k = bch2_btree_and_journal_iter_peek(&jiter);
897
898	bch2_bkey_buf_reassemble(s: out, c, k);
899
900	if ((flags & BTREE_ITER_PREFETCH) &&
901	c->opts.btree_node_prefetch)
902	ret = btree_path_prefetch_j(trans, path, jiter: &jiter);
903
904	bch2_btree_and_journal_iter_exit(&jiter);
905	return ret;
906	}
907
908	static __always_inline int btree_path_down(struct btree_trans *trans,
909	struct btree_path *path,
910	unsigned flags,
911	unsigned long trace_ip)
912	{
913	struct bch_fs *c = trans->c;
914	struct btree_path_level *l = path_l(path);
915	struct btree *b;
916	unsigned level = path->level - 1;
917	enum six_lock_type lock_type = __btree_lock_want(path, level);
918	struct bkey_buf tmp;
919	int ret;
920
921	EBUG_ON(!btree_node_locked(path, path->level));
922
923	bch2_bkey_buf_init(s: &tmp);
924
925	if (unlikely(trans->journal_replay_not_finished)) {
926	ret = btree_node_iter_and_journal_peek(trans, path, flags, out: &tmp);
927	if (ret)
928	goto err;
929	} else {
930	struct bkey_packed *k = bch2_btree_node_iter_peek(iter: &l->iter, b: l->b);
931	if (!k) {
932	struct printbuf buf = PRINTBUF;
933
934	prt_str(out: &buf, str: "node not found at pos ");
935	bch2_bpos_to_text(&buf, path->pos);
936	prt_str(out: &buf, str: " within parent node ");
937	bch2_bkey_val_to_text(&buf, c, bkey_i_to_s_c(k: &l->b->key));
938
939	bch2_fs_fatal_error(c, "%s", buf.buf);
940	printbuf_exit(&buf);
941	ret = -BCH_ERR_btree_need_topology_repair;
942	goto err;
943	}
944
945	bch2_bkey_buf_unpack(s: &tmp, c, b: l->b, src: k);
946
947	if ((flags & BTREE_ITER_PREFETCH) &&
948	c->opts.btree_node_prefetch) {
949	ret = btree_path_prefetch(trans, path);
950	if (ret)
951	goto err;
952	}
953	}
954
955	b = bch2_btree_node_get(trans, path, tmp.k, level, lock_type, trace_ip);
956	ret = PTR_ERR_OR_ZERO(ptr: b);
957	if (unlikely(ret))
958	goto err;
959
960	if (likely(!trans->journal_replay_not_finished &&
961	tmp.k->k.type == KEY_TYPE_btree_ptr_v2) &&
962	unlikely(b != btree_node_mem_ptr(tmp.k)))
963	btree_node_mem_ptr_set(trans, path, plevel: level + 1, b);
964
965	if (btree_node_read_locked(path, l: level + 1))
966	btree_node_unlock(trans, path, level: level + 1);
967
968	mark_btree_node_locked(trans, path, level,
969	type: (enum btree_node_locked_type) lock_type);
970	path->level = level;
971	bch2_btree_path_level_init(trans, path, b);
972
973	bch2_btree_path_verify_locks(path);
974	err:
975	bch2_bkey_buf_exit(s: &tmp, c);
976	return ret;
977	}
978
979	static int bch2_btree_path_traverse_all(struct btree_trans *trans)
980	{
981	struct bch_fs *c = trans->c;
982	struct btree_path *path;
983	unsigned long trace_ip = _RET_IP_;
984	unsigned i;
985	int ret = 0;
986
987	if (trans->in_traverse_all)
988	return -BCH_ERR_transaction_restart_in_traverse_all;
989
990	trans->in_traverse_all = true;
991	retry_all:
992	trans->restarted = 0;
993	trans->last_restarted_ip = 0;
994
995	trans_for_each_path(trans, path, i)
996	path->should_be_locked = false;
997
998	btree_trans_sort_paths(trans);
999
1000	bch2_trans_unlock(trans);
1001	cond_resched();
1002
1003	if (unlikely(trans->memory_allocation_failure)) {
1004	struct closure cl;
1005
1006	closure_init_stack(cl: &cl);
1007
1008	do {
1009	ret = bch2_btree_cache_cannibalize_lock(trans, &cl);
1010	closure_sync(cl: &cl);
1011	} while (ret);
1012	}
1013
1014	/* Now, redo traversals in correct order: */
1015	i = 0;
1016	while (i < trans->nr_sorted) {
1017	btree_path_idx_t idx = trans->sorted[i];
1018
1019	/*
1020	* Traversing a path can cause another path to be added at about
1021	* the same position:
1022	*/
1023	if (trans->paths[idx].uptodate) {
1024	__btree_path_get(path: &trans->paths[idx], intent: false);
1025	ret = bch2_btree_path_traverse_one(trans, idx, 0, _THIS_IP_);
1026	__btree_path_put(path: &trans->paths[idx], intent: false);
1027
1028	if (bch2_err_matches(ret, BCH_ERR_transaction_restart) ||
1029	bch2_err_matches(ret, ENOMEM))
1030	goto retry_all;
1031	if (ret)
1032	goto err;
1033	} else {
1034	i++;
1035	}
1036	}
1037
1038	/*
1039	* We used to assert that all paths had been traversed here
1040	* (path->uptodate < BTREE_ITER_NEED_TRAVERSE); however, since
1041	* path->should_be_locked is not set yet, we might have unlocked and
1042	* then failed to relock a path - that's fine.
1043	*/
1044	err:
1045	bch2_btree_cache_cannibalize_unlock(trans);
1046
1047	trans->in_traverse_all = false;
1048
1049	trace_and_count(c, trans_traverse_all, trans, trace_ip);
1050	return ret;
1051	}
1052
1053	static inline bool btree_path_check_pos_in_node(struct btree_path *path,
1054	unsigned l, int check_pos)
1055	{
1056	if (check_pos < 0 && btree_path_pos_before_node(path, b: path->l[l].b))
1057	return false;
1058	if (check_pos > 0 && btree_path_pos_after_node(path, b: path->l[l].b))
1059	return false;
1060	return true;
1061	}
1062
1063	static inline bool btree_path_good_node(struct btree_trans *trans,
1064	struct btree_path *path,
1065	unsigned l, int check_pos)
1066	{
1067	return is_btree_node(path, l) &&
1068	bch2_btree_node_relock(trans, path, level: l) &&
1069	btree_path_check_pos_in_node(path, l, check_pos);
1070	}
1071
1072	static void btree_path_set_level_down(struct btree_trans *trans,
1073	struct btree_path *path,
1074	unsigned new_level)
1075	{
1076	unsigned l;
1077
1078	path->level = new_level;
1079
1080	for (l = path->level + 1; l < BTREE_MAX_DEPTH; l++)
1081	if (btree_lock_want(path, level: l) == BTREE_NODE_UNLOCKED)
1082	btree_node_unlock(trans, path, level: l);
1083
1084	btree_path_set_dirty(path, u: BTREE_ITER_NEED_TRAVERSE);
1085	bch2_btree_path_verify(trans, path);
1086	}
1087
1088	static noinline unsigned __btree_path_up_until_good_node(struct btree_trans *trans,
1089	struct btree_path *path,
1090	int check_pos)
1091	{
1092	unsigned i, l = path->level;
1093	again:
1094	while (btree_path_node(path, level: l) &&
1095	!btree_path_good_node(trans, path, l, check_pos))
1096	__btree_path_set_level_up(trans, path, l: l++);
1097
1098	/* If we need intent locks, take them too: */
1099	for (i = l + 1;
1100	i < path->locks_want && btree_path_node(path, level: i);
1101	i++)
1102	if (!bch2_btree_node_relock(trans, path, level: i)) {
1103	while (l <= i)
1104	__btree_path_set_level_up(trans, path, l: l++);
1105	goto again;
1106	}
1107
1108	return l;
1109	}
1110
1111	static inline unsigned btree_path_up_until_good_node(struct btree_trans *trans,
1112	struct btree_path *path,
1113	int check_pos)
1114	{
1115	return likely(btree_node_locked(path, path->level) &&
1116	btree_path_check_pos_in_node(path, path->level, check_pos))
1117	? path->level
1118	: __btree_path_up_until_good_node(trans, path, check_pos);
1119	}
1120
1121	/*
1122	* This is the main state machine for walking down the btree - walks down to a
1123	* specified depth
1124	*
1125	* Returns 0 on success, -EIO on error (error reading in a btree node).
1126	*
1127	* On error, caller (peek_node()/peek_key()) must return NULL; the error is
1128	* stashed in the iterator and returned from bch2_trans_exit().
1129	*/
1130	int bch2_btree_path_traverse_one(struct btree_trans *trans,
1131	btree_path_idx_t path_idx,
1132	unsigned flags,
1133	unsigned long trace_ip)
1134	{
1135	struct btree_path *path = &trans->paths[path_idx];
1136	unsigned depth_want = path->level;
1137	int ret = -((int) trans->restarted);
1138
1139	if (unlikely(ret))
1140	goto out;
1141
1142	if (unlikely(!trans->srcu_held))
1143	bch2_trans_srcu_lock(trans);
1144
1145	/*
1146	* Ensure we obey path->should_be_locked: if it's set, we can't unlock
1147	* and re-traverse the path without a transaction restart:
1148	*/
1149	if (path->should_be_locked) {
1150	ret = bch2_btree_path_relock(trans, path, trace_ip);
1151	goto out;
1152	}
1153
1154	if (path->cached) {
1155	ret = bch2_btree_path_traverse_cached(trans, path, flags);
1156	goto out;
1157	}
1158
1159	path = &trans->paths[path_idx];
1160
1161	if (unlikely(path->level >= BTREE_MAX_DEPTH))
1162	goto out_uptodate;
1163
1164	path->level = btree_path_up_until_good_node(trans, path, check_pos: 0);
1165
1166	EBUG_ON(btree_path_node(path, path->level) &&
1167	!btree_node_locked(path, path->level));
1168
1169	/*
1170	* Note: path->nodes[path->level] may be temporarily NULL here - that
1171	* would indicate to other code that we got to the end of the btree,
1172	* here it indicates that relocking the root failed - it's critical that
1173	* btree_path_lock_root() comes next and that it can't fail
1174	*/
1175	while (path->level > depth_want) {
1176	ret = btree_path_node(path, level: path->level)
1177	? btree_path_down(trans, path, flags, trace_ip)
1178	: btree_path_lock_root(trans, path, depth_want, trace_ip);
1179	if (unlikely(ret)) {
1180	if (ret == 1) {
1181	/*
1182	* No nodes at this level - got to the end of
1183	* the btree:
1184	*/
1185	ret = 0;
1186	goto out;
1187	}
1188
1189	__bch2_btree_path_unlock(trans, path);
1190	path->level = depth_want;
1191	path->l[path->level].b = ERR_PTR(error: ret);
1192	goto out;
1193	}
1194	}
1195	out_uptodate:
1196	path->uptodate = BTREE_ITER_UPTODATE;
1197	out:
1198	if (bch2_err_matches(ret, BCH_ERR_transaction_restart) != !!trans->restarted)
1199	panic(fmt: "ret %s (%i) trans->restarted %s (%i)\n",
1200	bch2_err_str(ret), ret,
1201	bch2_err_str(trans->restarted), trans->restarted);
1202	bch2_btree_path_verify(trans, path);
1203	return ret;
1204	}
1205
1206	static inline void btree_path_copy(struct btree_trans *trans, struct btree_path *dst,
1207	struct btree_path *src)
1208	{
1209	unsigned i, offset = offsetof(struct btree_path, pos);
1210
1211	memcpy((void *) dst + offset,
1212	(void *) src + offset,
1213	sizeof(struct btree_path) - offset);
1214
1215	for (i = 0; i < BTREE_MAX_DEPTH; i++) {
1216	unsigned t = btree_node_locked_type(path: dst, level: i);
1217
1218	if (t != BTREE_NODE_UNLOCKED)
1219	six_lock_increment(&dst->l[i].b->c.lock, t);
1220	}
1221	}
1222
1223	static btree_path_idx_t btree_path_clone(struct btree_trans *trans, btree_path_idx_t src,
1224	bool intent)
1225	{
1226	btree_path_idx_t new = btree_path_alloc(trans, src);
1227	btree_path_copy(trans, dst: trans->paths + new, src: trans->paths + src);
1228	__btree_path_get(path: trans->paths + new, intent);
1229	return new;
1230	}
1231
1232	__flatten
1233	btree_path_idx_t __bch2_btree_path_make_mut(struct btree_trans *trans,
1234	btree_path_idx_t path, bool intent, unsigned long ip)
1235	{
1236	__btree_path_put(path: trans->paths + path, intent);
1237	path = btree_path_clone(trans, src: path, intent);
1238	trans->paths[path].preserve = false;
1239	return path;
1240	}
1241
1242	btree_path_idx_t __must_check
1243	__bch2_btree_path_set_pos(struct btree_trans *trans,
1244	btree_path_idx_t path_idx, struct bpos new_pos,
1245	bool intent, unsigned long ip)
1246	{
1247	int cmp = bpos_cmp(l: new_pos, r: trans->paths[path_idx].pos);
1248
1249	bch2_trans_verify_not_in_restart(trans);
1250	EBUG_ON(!trans->paths[path_idx].ref);
1251
1252	path_idx = bch2_btree_path_make_mut(trans, path: path_idx, intent, ip);
1253
1254	struct btree_path *path = trans->paths + path_idx;
1255	path->pos = new_pos;
1256	trans->paths_sorted = false;
1257
1258	if (unlikely(path->cached)) {
1259	btree_node_unlock(trans, path, level: 0);
1260	path->l[0].b = ERR_PTR(error: -BCH_ERR_no_btree_node_up);
1261	btree_path_set_dirty(path, u: BTREE_ITER_NEED_TRAVERSE);
1262	goto out;
1263	}
1264
1265	unsigned level = btree_path_up_until_good_node(trans, path, check_pos: cmp);
1266
1267	if (btree_path_node(path, level)) {
1268	struct btree_path_level *l = &path->l[level];
1269
1270	BUG_ON(!btree_node_locked(path, level));
1271	/*
1272	* We might have to skip over many keys, or just a few: try
1273	* advancing the node iterator, and if we have to skip over too
1274	* many keys just reinit it (or if we're rewinding, since that
1275	* is expensive).
1276	*/
1277	if (cmp < 0 ||
1278	!btree_path_advance_to_pos(path, l, max_advance: 8))
1279	bch2_btree_node_iter_init(&l->iter, l->b, &path->pos);
1280
1281	/*
1282	* Iterators to interior nodes should always be pointed at the first non
1283	* whiteout:
1284	*/
1285	if (unlikely(level))
1286	bch2_btree_node_iter_peek(iter: &l->iter, b: l->b);
1287	}
1288
1289	if (unlikely(level != path->level)) {
1290	btree_path_set_dirty(path, u: BTREE_ITER_NEED_TRAVERSE);
1291	__bch2_btree_path_unlock(trans, path);
1292	}
1293	out:
1294	bch2_btree_path_verify(trans, path);
1295	return path_idx;
1296	}
1297
1298	/* Btree path: main interface: */
1299
1300	static struct btree_path *have_path_at_pos(struct btree_trans *trans, struct btree_path *path)
1301	{
1302	struct btree_path *sib;
1303
1304	sib = prev_btree_path(trans, path);
1305	if (sib && !btree_path_cmp(l: sib, r: path))
1306	return sib;
1307
1308	sib = next_btree_path(trans, path);
1309	if (sib && !btree_path_cmp(l: sib, r: path))
1310	return sib;
1311
1312	return NULL;
1313	}
1314
1315	static struct btree_path *have_node_at_pos(struct btree_trans *trans, struct btree_path *path)
1316	{
1317	struct btree_path *sib;
1318
1319	sib = prev_btree_path(trans, path);
1320	if (sib && sib->level == path->level && path_l(path: sib)->b == path_l(path)->b)
1321	return sib;
1322
1323	sib = next_btree_path(trans, path);
1324	if (sib && sib->level == path->level && path_l(path: sib)->b == path_l(path)->b)
1325	return sib;
1326
1327	return NULL;
1328	}
1329
1330	static inline void __bch2_path_free(struct btree_trans *trans, btree_path_idx_t path)
1331	{
1332	__bch2_btree_path_unlock(trans, path: trans->paths + path);
1333	btree_path_list_remove(trans, trans->paths + path);
1334	__clear_bit(path, trans->paths_allocated);
1335	}
1336
1337	void bch2_path_put(struct btree_trans *trans, btree_path_idx_t path_idx, bool intent)
1338	{
1339	struct btree_path *path = trans->paths + path_idx, *dup;
1340
1341	if (!__btree_path_put(path, intent))
1342	return;
1343
1344	dup = path->preserve
1345	? have_path_at_pos(trans, path)
1346	: have_node_at_pos(trans, path);
1347
1348	if (!dup && !(!path->preserve && !is_btree_node(path, l: path->level)))
1349	return;
1350
1351	if (path->should_be_locked &&
1352	!trans->restarted &&
1353	(!dup || !bch2_btree_path_relock_norestart(trans, dup)))
1354	return;
1355
1356	if (dup) {
1357	dup->preserve |= path->preserve;
1358	dup->should_be_locked |= path->should_be_locked;
1359	}
1360
1361	__bch2_path_free(trans, path: path_idx);
1362	}
1363
1364	static void bch2_path_put_nokeep(struct btree_trans *trans, btree_path_idx_t path,
1365	bool intent)
1366	{
1367	if (!__btree_path_put(path: trans->paths + path, intent))
1368	return;
1369
1370	__bch2_path_free(trans, path);
1371	}
1372
1373	void __noreturn bch2_trans_restart_error(struct btree_trans *trans, u32 restart_count)
1374	{
1375	panic(fmt: "trans->restart_count %u, should be %u, last restarted by %pS\n",
1376	trans->restart_count, restart_count,
1377	(void *) trans->last_begin_ip);
1378	}
1379
1380	void __noreturn bch2_trans_in_restart_error(struct btree_trans *trans)
1381	{
1382	panic(fmt: "in transaction restart: %s, last restarted by %pS\n",
1383	bch2_err_str(trans->restarted),
1384	(void *) trans->last_restarted_ip);
1385	}
1386
1387	noinline __cold
1388	void bch2_trans_updates_to_text(struct printbuf *buf, struct btree_trans *trans)
1389	{
1390	prt_printf(buf, "transaction updates for %s journal seq %llu",
1391	trans->fn, trans->journal_res.seq);
1392	prt_newline(buf);
1393	printbuf_indent_add(buf, 2);
1394
1395	trans_for_each_update(trans, i) {
1396	struct bkey_s_c old = { &i->old_k, i->old_v };
1397
1398	prt_printf(buf, "update: btree=%s cached=%u %pS",
1399	bch2_btree_id_str(i->btree_id),
1400	i->cached,
1401	(void *) i->ip_allocated);
1402	prt_newline(buf);
1403
1404	prt_printf(buf, " old ");
1405	bch2_bkey_val_to_text(buf, trans->c, old);
1406	prt_newline(buf);
1407
1408	prt_printf(buf, " new ");
1409	bch2_bkey_val_to_text(buf, trans->c, bkey_i_to_s_c(k: i->k));
1410	prt_newline(buf);
1411	}
1412
1413	for (struct jset_entry *e = trans->journal_entries;
1414	e != btree_trans_journal_entries_top(trans);
1415	e = vstruct_next(e))
1416	bch2_journal_entry_to_text(buf, trans->c, e);
1417
1418	printbuf_indent_sub(buf, 2);
1419	}
1420
1421	noinline __cold
1422	void bch2_dump_trans_updates(struct btree_trans *trans)
1423	{
1424	struct printbuf buf = PRINTBUF;
1425
1426	bch2_trans_updates_to_text(buf: &buf, trans);
1427	bch2_print_string_as_lines(KERN_ERR, lines: buf.buf);
1428	printbuf_exit(&buf);
1429	}
1430
1431	static void bch2_btree_path_to_text(struct printbuf *out, struct btree_trans *trans, btree_path_idx_t path_idx)
1432	{
1433	struct btree_path *path = trans->paths + path_idx;
1434
1435	prt_printf(out, "path: idx %2u ref %u:%u %c %c btree=%s l=%u pos ",
1436	path_idx, path->ref, path->intent_ref,
1437	path->preserve ? 'P' : ' ',
1438	path->should_be_locked ? 'S' : ' ',
1439	bch2_btree_id_str(path->btree_id),
1440	path->level);
1441	bch2_bpos_to_text(out, path->pos);
1442
1443	prt_printf(out, " locks %u", path->nodes_locked);
1444	#ifdef TRACK_PATH_ALLOCATED
1445	prt_printf(out, " %pS", (void *) path->ip_allocated);
1446	#endif
1447	prt_newline(out);
1448	}
1449
1450	static noinline __cold
1451	void __bch2_trans_paths_to_text(struct printbuf *out, struct btree_trans *trans,
1452	bool nosort)
1453	{
1454	struct trans_for_each_path_inorder_iter iter;
1455
1456	if (!nosort)
1457	btree_trans_sort_paths(trans);
1458
1459	trans_for_each_path_idx_inorder(trans, iter)
1460	bch2_btree_path_to_text(out, trans, iter.path_idx);
1461	}
1462
1463	noinline __cold
1464	void bch2_trans_paths_to_text(struct printbuf *out, struct btree_trans *trans)
1465	{
1466	__bch2_trans_paths_to_text(out, trans, nosort: false);
1467	}
1468
1469	static noinline __cold
1470	void __bch2_dump_trans_paths_updates(struct btree_trans *trans, bool nosort)
1471	{
1472	struct printbuf buf = PRINTBUF;
1473
1474	__bch2_trans_paths_to_text(out: &buf, trans, nosort);
1475	bch2_trans_updates_to_text(buf: &buf, trans);
1476
1477	bch2_print_string_as_lines(KERN_ERR, lines: buf.buf);
1478	printbuf_exit(&buf);
1479	}
1480
1481	noinline __cold
1482	void bch2_dump_trans_paths_updates(struct btree_trans *trans)
1483	{
1484	__bch2_dump_trans_paths_updates(trans, nosort: false);
1485	}
1486
1487	noinline __cold
1488	static void bch2_trans_update_max_paths(struct btree_trans *trans)
1489	{
1490	struct btree_transaction_stats *s = btree_trans_stats(trans);
1491	struct printbuf buf = PRINTBUF;
1492	size_t nr = bitmap_weight(src: trans->paths_allocated, nbits: trans->nr_paths);
1493
1494	bch2_trans_paths_to_text(out: &buf, trans);
1495
1496	if (!buf.allocation_failure) {
1497	mutex_lock(&s->lock);
1498	if (nr > s->nr_max_paths) {
1499	s->nr_max_paths = nr;
1500	swap(s->max_paths_text, buf.buf);
1501	}
1502	mutex_unlock(lock: &s->lock);
1503	}
1504
1505	printbuf_exit(&buf);
1506
1507	trans->nr_paths_max = nr;
1508	}
1509
1510	noinline __cold
1511	int __bch2_btree_trans_too_many_iters(struct btree_trans *trans)
1512	{
1513	if (trace_trans_restart_too_many_iters_enabled()) {
1514	struct printbuf buf = PRINTBUF;
1515
1516	bch2_trans_paths_to_text(out: &buf, trans);
1517	trace_trans_restart_too_many_iters(trans, _THIS_IP_, paths: buf.buf);
1518	printbuf_exit(&buf);
1519	}
1520
1521	count_event(trans->c, trans_restart_too_many_iters);
1522
1523	return btree_trans_restart(trans, err: BCH_ERR_transaction_restart_too_many_iters);
1524	}
1525
1526	static noinline void btree_path_overflow(struct btree_trans *trans)
1527	{
1528	bch2_dump_trans_paths_updates(trans);
1529	bch_err(trans->c, "trans path overflow");
1530	}
1531
1532	static noinline void btree_paths_realloc(struct btree_trans *trans)
1533	{
1534	unsigned nr = trans->nr_paths * 2;
1535
1536	void *p = kvzalloc(BITS_TO_LONGS(nr) * sizeof(unsigned long) +
1537	sizeof(struct btree_trans_paths) +
1538	nr * sizeof(struct btree_path) +
1539	nr * sizeof(btree_path_idx_t) + 8 +
1540	nr * sizeof(struct btree_insert_entry), GFP_KERNEL|__GFP_NOFAIL);
1541
1542	unsigned long *paths_allocated = p;
1543	memcpy(paths_allocated, trans->paths_allocated, BITS_TO_LONGS(trans->nr_paths) * sizeof(unsigned long));
1544	p += BITS_TO_LONGS(nr) * sizeof(unsigned long);
1545
1546	p += sizeof(struct btree_trans_paths);
1547	struct btree_path *paths = p;
1548	*trans_paths_nr(paths) = nr;
1549	memcpy(paths, trans->paths, trans->nr_paths * sizeof(struct btree_path));
1550	p += nr * sizeof(struct btree_path);
1551
1552	btree_path_idx_t *sorted = p;
1553	memcpy(sorted, trans->sorted, trans->nr_sorted * sizeof(btree_path_idx_t));
1554	p += nr * sizeof(btree_path_idx_t) + 8;
1555
1556	struct btree_insert_entry *updates = p;
1557	memcpy(updates, trans->updates, trans->nr_paths * sizeof(struct btree_insert_entry));
1558
1559	unsigned long *old = trans->paths_allocated;
1560
1561	rcu_assign_pointer(trans->paths_allocated, paths_allocated);
1562	rcu_assign_pointer(trans->paths, paths);
1563	rcu_assign_pointer(trans->sorted, sorted);
1564	rcu_assign_pointer(trans->updates, updates);
1565
1566	trans->nr_paths = nr;
1567
1568	if (old != trans->_paths_allocated)
1569	kfree_rcu_mightsleep(old);
1570	}
1571
1572	static inline btree_path_idx_t btree_path_alloc(struct btree_trans *trans,
1573	btree_path_idx_t pos)
1574	{
1575	btree_path_idx_t idx = find_first_zero_bit(addr: trans->paths_allocated, size: trans->nr_paths);
1576
1577	if (unlikely(idx == trans->nr_paths)) {
1578	if (trans->nr_paths == BTREE_ITER_MAX) {
1579	btree_path_overflow(trans);
1580	return 0;
1581	}
1582
1583	btree_paths_realloc(trans);
1584	}
1585
1586	/*
1587	* Do this before marking the new path as allocated, since it won't be
1588	* initialized yet:
1589	*/
1590	if (unlikely(idx > trans->nr_paths_max))
1591	bch2_trans_update_max_paths(trans);
1592
1593	__set_bit(idx, trans->paths_allocated);
1594
1595	struct btree_path *path = &trans->paths[idx];
1596	path->ref = 0;
1597	path->intent_ref = 0;
1598	path->nodes_locked = 0;
1599
1600	btree_path_list_add(trans, pos, idx);
1601	trans->paths_sorted = false;
1602	return idx;
1603	}
1604
1605	btree_path_idx_t bch2_path_get(struct btree_trans *trans,
1606	enum btree_id btree_id, struct bpos pos,
1607	unsigned locks_want, unsigned level,
1608	unsigned flags, unsigned long ip)
1609	{
1610	struct btree_path *path;
1611	bool cached = flags & BTREE_ITER_CACHED;
1612	bool intent = flags & BTREE_ITER_INTENT;
1613	struct trans_for_each_path_inorder_iter iter;
1614	btree_path_idx_t path_pos = 0, path_idx;
1615
1616	bch2_trans_verify_not_in_restart(trans);
1617	bch2_trans_verify_locks(trans);
1618
1619	btree_trans_sort_paths(trans);
1620
1621	trans_for_each_path_inorder(trans, path, iter) {
1622	if (__btree_path_cmp(path,
1623	btree_id,
1624	cached,
1625	pos,
1626	level) > 0)
1627	break;
1628
1629	path_pos = iter.path_idx;
1630	}
1631
1632	if (path_pos &&
1633	trans->paths[path_pos].cached == cached &&
1634	trans->paths[path_pos].btree_id == btree_id &&
1635	trans->paths[path_pos].level == level) {
1636	__btree_path_get(trans->paths + path_pos, intent);
1637	path_idx = bch2_btree_path_set_pos(trans, path_pos, pos, intent, ip);
1638	path = trans->paths + path_idx;
1639	} else {
1640	path_idx = btree_path_alloc(trans, path_pos);
1641	path = trans->paths + path_idx;
1642
1643	__btree_path_get(path, intent);
1644	path->pos = pos;
1645	path->btree_id = btree_id;
1646	path->cached = cached;
1647	path->uptodate = BTREE_ITER_NEED_TRAVERSE;
1648	path->should_be_locked = false;
1649	path->level = level;
1650	path->locks_want = locks_want;
1651	path->nodes_locked = 0;
1652	for (unsigned i = 0; i < ARRAY_SIZE(path->l); i++)
1653	path->l[i].b = ERR_PTR(-BCH_ERR_no_btree_node_init);
1654	#ifdef TRACK_PATH_ALLOCATED
1655	path->ip_allocated = ip;
1656	#endif
1657	trans->paths_sorted = false;
1658	}
1659
1660	if (!(flags & BTREE_ITER_NOPRESERVE))
1661	path->preserve = true;
1662
1663	if (path->intent_ref)
1664	locks_want = max(locks_want, level + 1);
1665
1666	/*
1667	* If the path has locks_want greater than requested, we don't downgrade
1668	* it here - on transaction restart because btree node split needs to
1669	* upgrade locks, we might be putting/getting the iterator again.
1670	* Downgrading iterators only happens via bch2_trans_downgrade(), after
1671	* a successful transaction commit.
1672	*/
1673
1674	locks_want = min(locks_want, BTREE_MAX_DEPTH);
1675	if (locks_want > path->locks_want)
1676	bch2_btree_path_upgrade_noupgrade_sibs(trans, path, locks_want, NULL);
1677
1678	return path_idx;
1679	}
1680
1681	struct bkey_s_c bch2_btree_path_peek_slot(struct btree_path *path, struct bkey *u)
1682	{
1683
1684	struct btree_path_level *l = path_l(path);
1685	struct bkey_packed *_k;
1686	struct bkey_s_c k;
1687
1688	if (unlikely(!l->b))
1689	return bkey_s_c_null;
1690
1691	EBUG_ON(path->uptodate != BTREE_ITER_UPTODATE);
1692	EBUG_ON(!btree_node_locked(path, path->level));
1693
1694	if (!path->cached) {
1695	_k = bch2_btree_node_iter_peek_all(iter: &l->iter, b: l->b);
1696	k = _k ? bkey_disassemble(b: l->b, k: _k, u) : bkey_s_c_null;
1697
1698	EBUG_ON(k.k && bkey_deleted(k.k) && bpos_eq(k.k->p, path->pos));
1699
1700	if (!k.k || !bpos_eq(l: path->pos, r: k.k->p))
1701	goto hole;
1702	} else {
1703	struct bkey_cached *ck = (void *) path->l[0].b;
1704
1705	EBUG_ON(ck &&
1706	(path->btree_id != ck->key.btree_id ||
1707	!bkey_eq(path->pos, ck->key.pos)));
1708	if (!ck || !ck->valid)
1709	return bkey_s_c_null;
1710
1711	*u = ck->k->k;
1712	k = bkey_i_to_s_c(k: ck->k);
1713	}
1714
1715	return k;
1716	hole:
1717	bkey_init(k: u);
1718	u->p = path->pos;
1719	return (struct bkey_s_c) { u, NULL };
1720	}
1721
1722	/* Btree iterators: */
1723
1724	int __must_check
1725	__bch2_btree_iter_traverse(struct btree_iter *iter)
1726	{
1727	return bch2_btree_path_traverse(trans: iter->trans, path: iter->path, flags: iter->flags);
1728	}
1729
1730	int __must_check
1731	bch2_btree_iter_traverse(struct btree_iter *iter)
1732	{
1733	struct btree_trans *trans = iter->trans;
1734	int ret;
1735
1736	iter->path = bch2_btree_path_set_pos(trans, path: iter->path,
1737	new_pos: btree_iter_search_key(iter),
1738	intent: iter->flags & BTREE_ITER_INTENT,
1739	ip: btree_iter_ip_allocated(iter));
1740
1741	ret = bch2_btree_path_traverse(trans: iter->trans, path: iter->path, flags: iter->flags);
1742	if (ret)
1743	return ret;
1744
1745	struct btree_path *path = btree_iter_path(trans, iter);
1746	if (btree_path_node(path, level: path->level))
1747	btree_path_set_should_be_locked(path);
1748	return 0;
1749	}
1750
1751	/* Iterate across nodes (leaf and interior nodes) */
1752
1753	struct btree *bch2_btree_iter_peek_node(struct btree_iter *iter)
1754	{
1755	struct btree_trans *trans = iter->trans;
1756	struct btree *b = NULL;
1757	int ret;
1758
1759	EBUG_ON(trans->paths[iter->path].cached);
1760	bch2_btree_iter_verify(iter);
1761
1762	ret = bch2_btree_path_traverse(trans, path: iter->path, flags: iter->flags);
1763	if (ret)
1764	goto err;
1765
1766	struct btree_path *path = btree_iter_path(trans, iter);
1767	b = btree_path_node(path, level: path->level);
1768	if (!b)
1769	goto out;
1770
1771	BUG_ON(bpos_lt(b->key.k.p, iter->pos));
1772
1773	bkey_init(k: &iter->k);
1774	iter->k.p = iter->pos = b->key.k.p;
1775
1776	iter->path = bch2_btree_path_set_pos(trans, path: iter->path, new_pos: b->key.k.p,
1777	intent: iter->flags & BTREE_ITER_INTENT,
1778	ip: btree_iter_ip_allocated(iter));
1779	btree_path_set_should_be_locked(path: btree_iter_path(trans, iter));
1780	out:
1781	bch2_btree_iter_verify_entry_exit(iter);
1782	bch2_btree_iter_verify(iter);
1783
1784	return b;
1785	err:
1786	b = ERR_PTR(error: ret);
1787	goto out;
1788	}
1789
1790	struct btree *bch2_btree_iter_peek_node_and_restart(struct btree_iter *iter)
1791	{
1792	struct btree *b;
1793
1794	while (b = bch2_btree_iter_peek_node(iter),
1795	bch2_err_matches(PTR_ERR_OR_ZERO(b), BCH_ERR_transaction_restart))
1796	bch2_trans_begin(iter->trans);
1797
1798	return b;
1799	}
1800
1801	struct btree *bch2_btree_iter_next_node(struct btree_iter *iter)
1802	{
1803	struct btree_trans *trans = iter->trans;
1804	struct btree *b = NULL;
1805	int ret;
1806
1807	EBUG_ON(trans->paths[iter->path].cached);
1808	bch2_trans_verify_not_in_restart(trans);
1809	bch2_btree_iter_verify(iter);
1810
1811	struct btree_path *path = btree_iter_path(trans, iter);
1812
1813	/* already at end? */
1814	if (!btree_path_node(path, level: path->level))
1815	return NULL;
1816
1817	/* got to end? */
1818	if (!btree_path_node(path, level: path->level + 1)) {
1819	btree_path_set_level_up(trans, path);
1820	return NULL;
1821	}
1822
1823	if (!bch2_btree_node_relock(trans, path, level: path->level + 1)) {
1824	__bch2_btree_path_unlock(trans, path);
1825	path->l[path->level].b = ERR_PTR(error: -BCH_ERR_no_btree_node_relock);
1826	path->l[path->level + 1].b = ERR_PTR(error: -BCH_ERR_no_btree_node_relock);
1827	btree_path_set_dirty(path, u: BTREE_ITER_NEED_TRAVERSE);
1828	trace_and_count(trans->c, trans_restart_relock_next_node, trans, _THIS_IP_, path);
1829	ret = btree_trans_restart(trans, err: BCH_ERR_transaction_restart_relock);
1830	goto err;
1831	}
1832
1833	b = btree_path_node(path, level: path->level + 1);
1834
1835	if (bpos_eq(l: iter->pos, r: b->key.k.p)) {
1836	__btree_path_set_level_up(trans, path, l: path->level++);
1837	} else {
1838	/*
1839	* Haven't gotten to the end of the parent node: go back down to
1840	* the next child node
1841	*/
1842	iter->path = bch2_btree_path_set_pos(trans, path: iter->path,
1843	new_pos: bpos_successor(p: iter->pos),
1844	intent: iter->flags & BTREE_ITER_INTENT,
1845	ip: btree_iter_ip_allocated(iter));
1846
1847	path = btree_iter_path(trans, iter);
1848	btree_path_set_level_down(trans, path, new_level: iter->min_depth);
1849
1850	ret = bch2_btree_path_traverse(trans, path: iter->path, flags: iter->flags);
1851	if (ret)
1852	goto err;
1853
1854	path = btree_iter_path(trans, iter);
1855	b = path->l[path->level].b;
1856	}
1857
1858	bkey_init(k: &iter->k);
1859	iter->k.p = iter->pos = b->key.k.p;
1860
1861	iter->path = bch2_btree_path_set_pos(trans, path: iter->path, new_pos: b->key.k.p,
1862	intent: iter->flags & BTREE_ITER_INTENT,
1863	ip: btree_iter_ip_allocated(iter));
1864	btree_path_set_should_be_locked(path: btree_iter_path(trans, iter));
1865	EBUG_ON(btree_iter_path(trans, iter)->uptodate);
1866	out:
1867	bch2_btree_iter_verify_entry_exit(iter);
1868	bch2_btree_iter_verify(iter);
1869
1870	return b;
1871	err:
1872	b = ERR_PTR(error: ret);
1873	goto out;
1874	}
1875
1876	/* Iterate across keys (in leaf nodes only) */
1877
1878	inline bool bch2_btree_iter_advance(struct btree_iter *iter)
1879	{
1880	struct bpos pos = iter->k.p;
1881	bool ret = !(iter->flags & BTREE_ITER_ALL_SNAPSHOTS
1882	? bpos_eq(l: pos, SPOS_MAX)
1883	: bkey_eq(l: pos, SPOS_MAX));
1884
1885	if (ret && !(iter->flags & BTREE_ITER_IS_EXTENTS))
1886	pos = bkey_successor(iter, p: pos);
1887	bch2_btree_iter_set_pos(iter, new_pos: pos);
1888	return ret;
1889	}
1890
1891	inline bool bch2_btree_iter_rewind(struct btree_iter *iter)
1892	{
1893	struct bpos pos = bkey_start_pos(k: &iter->k);
1894	bool ret = !(iter->flags & BTREE_ITER_ALL_SNAPSHOTS
1895	? bpos_eq(l: pos, POS_MIN)
1896	: bkey_eq(l: pos, POS_MIN));
1897
1898	if (ret && !(iter->flags & BTREE_ITER_IS_EXTENTS))
1899	pos = bkey_predecessor(iter, p: pos);
1900	bch2_btree_iter_set_pos(iter, new_pos: pos);
1901	return ret;
1902	}
1903
1904	static noinline
1905	void bch2_btree_trans_peek_prev_updates(struct btree_trans *trans, struct btree_iter *iter,
1906	struct bkey_s_c *k)
1907	{
1908	struct bpos end = path_l(path: btree_iter_path(trans, iter))->b->data->min_key;
1909
1910	trans_for_each_update(trans, i)
1911	if (!i->key_cache_already_flushed &&
1912	i->btree_id == iter->btree_id &&
1913	bpos_le(l: i->k->k.p, r: iter->pos) &&
1914	bpos_ge(l: i->k->k.p, r: k->k ? k->k->p : end)) {
1915	iter->k = i->k->k;
1916	*k = bkey_i_to_s_c(k: i->k);
1917	}
1918	}
1919
1920	static noinline
1921	void bch2_btree_trans_peek_updates(struct btree_trans *trans, struct btree_iter *iter,
1922	struct bkey_s_c *k)
1923	{
1924	struct btree_path *path = btree_iter_path(trans, iter);
1925	struct bpos end = path_l(path)->b->key.k.p;
1926
1927	trans_for_each_update(trans, i)
1928	if (!i->key_cache_already_flushed &&
1929	i->btree_id == iter->btree_id &&
1930	bpos_ge(l: i->k->k.p, r: path->pos) &&
1931	bpos_le(l: i->k->k.p, r: k->k ? k->k->p : end)) {
1932	iter->k = i->k->k;
1933	*k = bkey_i_to_s_c(k: i->k);
1934	}
1935	}
1936
1937	static noinline
1938	void bch2_btree_trans_peek_slot_updates(struct btree_trans *trans, struct btree_iter *iter,
1939	struct bkey_s_c *k)
1940	{
1941	trans_for_each_update(trans, i)
1942	if (!i->key_cache_already_flushed &&
1943	i->btree_id == iter->btree_id &&
1944	bpos_eq(l: i->k->k.p, r: iter->pos)) {
1945	iter->k = i->k->k;
1946	*k = bkey_i_to_s_c(k: i->k);
1947	}
1948	}
1949
1950	static struct bkey_i *bch2_btree_journal_peek(struct btree_trans *trans,
1951	struct btree_iter *iter,
1952	struct bpos end_pos)
1953	{
1954	struct btree_path *path = btree_iter_path(trans, iter);
1955
1956	return bch2_journal_keys_peek_upto(trans->c, iter->btree_id,
1957	path->level,
1958	path->pos,
1959	end_pos,
1960	&iter->journal_idx);
1961	}
1962
1963	static noinline
1964	struct bkey_s_c btree_trans_peek_slot_journal(struct btree_trans *trans,
1965	struct btree_iter *iter)
1966	{
1967	struct btree_path *path = btree_iter_path(trans, iter);
1968	struct bkey_i *k = bch2_btree_journal_peek(trans, iter, end_pos: path->pos);
1969
1970	if (k) {
1971	iter->k = k->k;
1972	return bkey_i_to_s_c(k);
1973	} else {
1974	return bkey_s_c_null;
1975	}
1976	}
1977
1978	static noinline
1979	struct bkey_s_c btree_trans_peek_journal(struct btree_trans *trans,
1980	struct btree_iter *iter,
1981	struct bkey_s_c k)
1982	{
1983	struct btree_path *path = btree_iter_path(trans, iter);
1984	struct bkey_i *next_journal =
1985	bch2_btree_journal_peek(trans, iter,
1986	end_pos: k.k ? k.k->p : path_l(path)->b->key.k.p);
1987
1988	if (next_journal) {
1989	iter->k = next_journal->k;
1990	k = bkey_i_to_s_c(k: next_journal);
1991	}
1992
1993	return k;
1994	}
1995
1996	/*
1997	* Checks btree key cache for key at iter->pos and returns it if present, or
1998	* bkey_s_c_null:
1999	*/
2000	static noinline
2001	struct bkey_s_c btree_trans_peek_key_cache(struct btree_iter *iter, struct bpos pos)
2002	{
2003	struct btree_trans *trans = iter->trans;
2004	struct bch_fs *c = trans->c;
2005	struct bkey u;
2006	struct bkey_s_c k;
2007	int ret;
2008
2009	if ((iter->flags & BTREE_ITER_KEY_CACHE_FILL) &&
2010	bpos_eq(l: iter->pos, r: pos))
2011	return bkey_s_c_null;
2012
2013	if (!bch2_btree_key_cache_find(c, iter->btree_id, pos))
2014	return bkey_s_c_null;
2015
2016	if (!iter->key_cache_path)
2017	iter->key_cache_path = bch2_path_get(trans, btree_id: iter->btree_id, pos,
2018	locks_want: iter->flags & BTREE_ITER_INTENT, level: 0,
2019	flags: iter->flags|BTREE_ITER_CACHED|
2020	BTREE_ITER_CACHED_NOFILL,
2021	_THIS_IP_);
2022
2023	iter->key_cache_path = bch2_btree_path_set_pos(trans, path: iter->key_cache_path, new_pos: pos,
2024	intent: iter->flags & BTREE_ITER_INTENT,
2025	ip: btree_iter_ip_allocated(iter));
2026
2027	ret = bch2_btree_path_traverse(trans, path: iter->key_cache_path,
2028	flags: iter->flags|BTREE_ITER_CACHED) ?:
2029	bch2_btree_path_relock(trans, path: btree_iter_path(trans, iter), _THIS_IP_);
2030	if (unlikely(ret))
2031	return bkey_s_c_err(ret);
2032
2033	btree_path_set_should_be_locked(path: trans->paths + iter->key_cache_path);
2034
2035	k = bch2_btree_path_peek_slot(path: trans->paths + iter->key_cache_path, u: &u);
2036	if (k.k && !bkey_err(k)) {
2037	iter->k = u;
2038	k.k = &iter->k;
2039	}
2040	return k;
2041	}
2042
2043	static struct bkey_s_c __bch2_btree_iter_peek(struct btree_iter *iter, struct bpos search_key)
2044	{
2045	struct btree_trans *trans = iter->trans;
2046	struct bkey_s_c k, k2;
2047	int ret;
2048
2049	EBUG_ON(btree_iter_path(trans, iter)->cached);
2050	bch2_btree_iter_verify(iter);
2051
2052	while (1) {
2053	struct btree_path_level *l;
2054
2055	iter->path = bch2_btree_path_set_pos(trans, path: iter->path, new_pos: search_key,
2056	intent: iter->flags & BTREE_ITER_INTENT,
2057	ip: btree_iter_ip_allocated(iter));
2058
2059	ret = bch2_btree_path_traverse(trans, path: iter->path, flags: iter->flags);
2060	if (unlikely(ret)) {
2061	/* ensure that iter->k is consistent with iter->pos: */
2062	bch2_btree_iter_set_pos(iter, new_pos: iter->pos);
2063	k = bkey_s_c_err(ret);
2064	goto out;
2065	}
2066
2067	struct btree_path *path = btree_iter_path(trans, iter);
2068	l = path_l(path);
2069
2070	if (unlikely(!l->b)) {
2071	/* No btree nodes at requested level: */
2072	bch2_btree_iter_set_pos(iter, SPOS_MAX);
2073	k = bkey_s_c_null;
2074	goto out;
2075	}
2076
2077	btree_path_set_should_be_locked(path);
2078
2079	k = btree_path_level_peek_all(c: trans->c, l, u: &iter->k);
2080
2081	if (unlikely(iter->flags & BTREE_ITER_WITH_KEY_CACHE) &&
2082	k.k &&
2083	(k2 = btree_trans_peek_key_cache(iter, pos: k.k->p)).k) {
2084	k = k2;
2085	ret = bkey_err(k);
2086	if (ret) {
2087	bch2_btree_iter_set_pos(iter, new_pos: iter->pos);
2088	goto out;
2089	}
2090	}
2091
2092	if (unlikely(iter->flags & BTREE_ITER_WITH_JOURNAL))
2093	k = btree_trans_peek_journal(trans, iter, k);
2094
2095	if (unlikely((iter->flags & BTREE_ITER_WITH_UPDATES) &&
2096	trans->nr_updates))
2097	bch2_btree_trans_peek_updates(trans, iter, k: &k);
2098
2099	if (k.k && bkey_deleted(k.k)) {
2100	/*
2101	* If we've got a whiteout, and it's after the search
2102	* key, advance the search key to the whiteout instead
2103	* of just after the whiteout - it might be a btree
2104	* whiteout, with a real key at the same position, since
2105	* in the btree deleted keys sort before non deleted.
2106	*/
2107	search_key = !bpos_eq(l: search_key, r: k.k->p)
2108	? k.k->p
2109	: bpos_successor(p: k.k->p);
2110	continue;
2111	}
2112
2113	if (likely(k.k)) {
2114	break;
2115	} else if (likely(!bpos_eq(l->b->key.k.p, SPOS_MAX))) {
2116	/* Advance to next leaf node: */
2117	search_key = bpos_successor(p: l->b->key.k.p);
2118	} else {
2119	/* End of btree: */
2120	bch2_btree_iter_set_pos(iter, SPOS_MAX);
2121	k = bkey_s_c_null;
2122	goto out;
2123	}
2124	}
2125	out:
2126	bch2_btree_iter_verify(iter);
2127
2128	return k;
2129	}
2130
2131	/**
2132	* bch2_btree_iter_peek_upto() - returns first key greater than or equal to
2133	* iterator's current position
2134	* @iter: iterator to peek from
2135	* @end: search limit: returns keys less than or equal to @end
2136	*
2137	* Returns: key if found, or an error extractable with bkey_err().
2138	*/
2139	struct bkey_s_c bch2_btree_iter_peek_upto(struct btree_iter *iter, struct bpos end)
2140	{
2141	struct btree_trans *trans = iter->trans;
2142	struct bpos search_key = btree_iter_search_key(iter);
2143	struct bkey_s_c k;
2144	struct bpos iter_pos;
2145	int ret;
2146
2147	EBUG_ON((iter->flags & BTREE_ITER_FILTER_SNAPSHOTS) && bkey_eq(end, POS_MAX));
2148
2149	if (iter->update_path) {
2150	bch2_path_put_nokeep(trans, path: iter->update_path,
2151	intent: iter->flags & BTREE_ITER_INTENT);
2152	iter->update_path = 0;
2153	}
2154
2155	bch2_btree_iter_verify_entry_exit(iter);
2156
2157	while (1) {
2158	k = __bch2_btree_iter_peek(iter, search_key);
2159	if (unlikely(!k.k))
2160	goto end;
2161	if (unlikely(bkey_err(k)))
2162	goto out_no_locked;
2163
2164	/*
2165	* We need to check against @end before FILTER_SNAPSHOTS because
2166	* if we get to a different inode that requested we might be
2167	* seeing keys for a different snapshot tree that will all be
2168	* filtered out.
2169	*
2170	* But we can't do the full check here, because bkey_start_pos()
2171	* isn't monotonically increasing before FILTER_SNAPSHOTS, and
2172	* that's what we check against in extents mode:
2173	*/
2174	if (unlikely(!(iter->flags & BTREE_ITER_IS_EXTENTS)
2175	? bkey_gt(k.k->p, end)
2176	: k.k->p.inode > end.inode))
2177	goto end;
2178
2179	if (iter->update_path &&
2180	!bkey_eq(l: trans->paths[iter->update_path].pos, r: k.k->p)) {
2181	bch2_path_put_nokeep(trans, path: iter->update_path,
2182	intent: iter->flags & BTREE_ITER_INTENT);
2183	iter->update_path = 0;
2184	}
2185
2186	if ((iter->flags & BTREE_ITER_FILTER_SNAPSHOTS) &&
2187	(iter->flags & BTREE_ITER_INTENT) &&
2188	!(iter->flags & BTREE_ITER_IS_EXTENTS) &&
2189	!iter->update_path) {
2190	struct bpos pos = k.k->p;
2191
2192	if (pos.snapshot < iter->snapshot) {
2193	search_key = bpos_successor(p: k.k->p);
2194	continue;
2195	}
2196
2197	pos.snapshot = iter->snapshot;
2198
2199	/*
2200	* advance, same as on exit for iter->path, but only up
2201	* to snapshot
2202	*/
2203	__btree_path_get(path: trans->paths + iter->path, intent: iter->flags & BTREE_ITER_INTENT);
2204	iter->update_path = iter->path;
2205
2206	iter->update_path = bch2_btree_path_set_pos(trans,
2207	path: iter->update_path, new_pos: pos,
2208	intent: iter->flags & BTREE_ITER_INTENT,
2209	_THIS_IP_);
2210	ret = bch2_btree_path_traverse(trans, path: iter->update_path, flags: iter->flags);
2211	if (unlikely(ret)) {
2212	k = bkey_s_c_err(ret);
2213	goto out_no_locked;
2214	}
2215	}
2216
2217	/*
2218	* We can never have a key in a leaf node at POS_MAX, so
2219	* we don't have to check these successor() calls:
2220	*/
2221	if ((iter->flags & BTREE_ITER_FILTER_SNAPSHOTS) &&
2222	!bch2_snapshot_is_ancestor(c: trans->c,
2223	id: iter->snapshot,
2224	ancestor: k.k->p.snapshot)) {
2225	search_key = bpos_successor(p: k.k->p);
2226	continue;
2227	}
2228
2229	if (bkey_whiteout(k.k) &&
2230	!(iter->flags & BTREE_ITER_ALL_SNAPSHOTS)) {
2231	search_key = bkey_successor(iter, p: k.k->p);
2232	continue;
2233	}
2234
2235	/*
2236	* iter->pos should be mononotically increasing, and always be
2237	* equal to the key we just returned - except extents can
2238	* straddle iter->pos:
2239	*/
2240	if (!(iter->flags & BTREE_ITER_IS_EXTENTS))
2241	iter_pos = k.k->p;
2242	else
2243	iter_pos = bkey_max(l: iter->pos, r: bkey_start_pos(k: k.k));
2244
2245	if (unlikely(!(iter->flags & BTREE_ITER_IS_EXTENTS)
2246	? bkey_gt(iter_pos, end)
2247	: bkey_ge(iter_pos, end)))
2248	goto end;
2249
2250	break;
2251	}
2252
2253	iter->pos = iter_pos;
2254
2255	iter->path = bch2_btree_path_set_pos(trans, path: iter->path, new_pos: k.k->p,
2256	intent: iter->flags & BTREE_ITER_INTENT,
2257	ip: btree_iter_ip_allocated(iter));
2258
2259	btree_path_set_should_be_locked(path: btree_iter_path(trans, iter));
2260	out_no_locked:
2261	if (iter->update_path) {
2262	ret = bch2_btree_path_relock(trans, path: trans->paths + iter->update_path, _THIS_IP_);
2263	if (unlikely(ret))
2264	k = bkey_s_c_err(ret);
2265	else
2266	btree_path_set_should_be_locked(path: trans->paths + iter->update_path);
2267	}
2268
2269	if (!(iter->flags & BTREE_ITER_ALL_SNAPSHOTS))
2270	iter->pos.snapshot = iter->snapshot;
2271
2272	ret = bch2_btree_iter_verify_ret(iter, k);
2273	if (unlikely(ret)) {
2274	bch2_btree_iter_set_pos(iter, new_pos: iter->pos);
2275	k = bkey_s_c_err(ret);
2276	}
2277
2278	bch2_btree_iter_verify_entry_exit(iter);
2279
2280	return k;
2281	end:
2282	bch2_btree_iter_set_pos(iter, new_pos: end);
2283	k = bkey_s_c_null;
2284	goto out_no_locked;
2285	}
2286
2287	/**
2288	* bch2_btree_iter_next() - returns first key greater than iterator's current
2289	* position
2290	* @iter: iterator to peek from
2291	*
2292	* Returns: key if found, or an error extractable with bkey_err().
2293	*/
2294	struct bkey_s_c bch2_btree_iter_next(struct btree_iter *iter)
2295	{
2296	if (!bch2_btree_iter_advance(iter))
2297	return bkey_s_c_null;
2298
2299	return bch2_btree_iter_peek(iter);
2300	}
2301
2302	/**
2303	* bch2_btree_iter_peek_prev() - returns first key less than or equal to
2304	* iterator's current position
2305	* @iter: iterator to peek from
2306	*
2307	* Returns: key if found, or an error extractable with bkey_err().
2308	*/
2309	struct bkey_s_c bch2_btree_iter_peek_prev(struct btree_iter *iter)
2310	{
2311	struct btree_trans *trans = iter->trans;
2312	struct bpos search_key = iter->pos;
2313	struct bkey_s_c k;
2314	struct bkey saved_k;
2315	const struct bch_val *saved_v;
2316	btree_path_idx_t saved_path = 0;
2317	int ret;
2318
2319	EBUG_ON(btree_iter_path(trans, iter)->cached ||
2320	btree_iter_path(trans, iter)->level);
2321
2322	if (iter->flags & BTREE_ITER_WITH_JOURNAL)
2323	return bkey_s_c_err(-BCH_ERR_btree_iter_with_journal_not_supported);
2324
2325	bch2_btree_iter_verify(iter);
2326	bch2_btree_iter_verify_entry_exit(iter);
2327
2328	if (iter->flags & BTREE_ITER_FILTER_SNAPSHOTS)
2329	search_key.snapshot = U32_MAX;
2330
2331	while (1) {
2332	iter->path = bch2_btree_path_set_pos(trans, path: iter->path, new_pos: search_key,
2333	intent: iter->flags & BTREE_ITER_INTENT,
2334	ip: btree_iter_ip_allocated(iter));
2335
2336	ret = bch2_btree_path_traverse(trans, path: iter->path, flags: iter->flags);
2337	if (unlikely(ret)) {
2338	/* ensure that iter->k is consistent with iter->pos: */
2339	bch2_btree_iter_set_pos(iter, new_pos: iter->pos);
2340	k = bkey_s_c_err(ret);
2341	goto out_no_locked;
2342	}
2343
2344	struct btree_path *path = btree_iter_path(trans, iter);
2345
2346	k = btree_path_level_peek(trans, path, l: &path->l[0], u: &iter->k);
2347	if (!k.k ||
2348	((iter->flags & BTREE_ITER_IS_EXTENTS)
2349	? bpos_ge(l: bkey_start_pos(k: k.k), r: search_key)
2350	: bpos_gt(l: k.k->p, r: search_key)))
2351	k = btree_path_level_prev(trans, path, l: &path->l[0], u: &iter->k);
2352
2353	if (unlikely((iter->flags & BTREE_ITER_WITH_UPDATES) &&
2354	trans->nr_updates))
2355	bch2_btree_trans_peek_prev_updates(trans, iter, k: &k);
2356
2357	if (likely(k.k)) {
2358	if (iter->flags & BTREE_ITER_FILTER_SNAPSHOTS) {
2359	if (k.k->p.snapshot == iter->snapshot)
2360	goto got_key;
2361
2362	/*
2363	* If we have a saved candidate, and we're no
2364	* longer at the same _key_ (not pos), return
2365	* that candidate
2366	*/
2367	if (saved_path && !bkey_eq(l: k.k->p, r: saved_k.p)) {
2368	bch2_path_put_nokeep(trans, path: iter->path,
2369	intent: iter->flags & BTREE_ITER_INTENT);
2370	iter->path = saved_path;
2371	saved_path = 0;
2372	iter->k = saved_k;
2373	k.v = saved_v;
2374	goto got_key;
2375	}
2376
2377	if (bch2_snapshot_is_ancestor(c: trans->c,
2378	id: iter->snapshot,
2379	ancestor: k.k->p.snapshot)) {
2380	if (saved_path)
2381	bch2_path_put_nokeep(trans, path: saved_path,
2382	intent: iter->flags & BTREE_ITER_INTENT);
2383	saved_path = btree_path_clone(trans, src: iter->path,
2384	intent: iter->flags & BTREE_ITER_INTENT);
2385	path = btree_iter_path(trans, iter);
2386	saved_k = *k.k;
2387	saved_v = k.v;
2388	}
2389
2390	search_key = bpos_predecessor(p: k.k->p);
2391	continue;
2392	}
2393	got_key:
2394	if (bkey_whiteout(k.k) &&
2395	!(iter->flags & BTREE_ITER_ALL_SNAPSHOTS)) {
2396	search_key = bkey_predecessor(iter, p: k.k->p);
2397	if (iter->flags & BTREE_ITER_FILTER_SNAPSHOTS)
2398	search_key.snapshot = U32_MAX;
2399	continue;
2400	}
2401
2402	btree_path_set_should_be_locked(path);
2403	break;
2404	} else if (likely(!bpos_eq(path->l[0].b->data->min_key, POS_MIN))) {
2405	/* Advance to previous leaf node: */
2406	search_key = bpos_predecessor(p: path->l[0].b->data->min_key);
2407	} else {
2408	/* Start of btree: */
2409	bch2_btree_iter_set_pos(iter, POS_MIN);
2410	k = bkey_s_c_null;
2411	goto out_no_locked;
2412	}
2413	}
2414
2415	EBUG_ON(bkey_gt(bkey_start_pos(k.k), iter->pos));
2416
2417	/* Extents can straddle iter->pos: */
2418	if (bkey_lt(l: k.k->p, r: iter->pos))
2419	iter->pos = k.k->p;
2420
2421	if (iter->flags & BTREE_ITER_FILTER_SNAPSHOTS)
2422	iter->pos.snapshot = iter->snapshot;
2423	out_no_locked:
2424	if (saved_path)
2425	bch2_path_put_nokeep(trans, path: saved_path, intent: iter->flags & BTREE_ITER_INTENT);
2426
2427	bch2_btree_iter_verify_entry_exit(iter);
2428	bch2_btree_iter_verify(iter);
2429
2430	return k;
2431	}
2432
2433	/**
2434	* bch2_btree_iter_prev() - returns first key less than iterator's current
2435	* position
2436	* @iter: iterator to peek from
2437	*
2438	* Returns: key if found, or an error extractable with bkey_err().
2439	*/
2440	struct bkey_s_c bch2_btree_iter_prev(struct btree_iter *iter)
2441	{
2442	if (!bch2_btree_iter_rewind(iter))
2443	return bkey_s_c_null;
2444
2445	return bch2_btree_iter_peek_prev(iter);
2446	}
2447
2448	struct bkey_s_c bch2_btree_iter_peek_slot(struct btree_iter *iter)
2449	{
2450	struct btree_trans *trans = iter->trans;
2451	struct bpos search_key;
2452	struct bkey_s_c k;
2453	int ret;
2454
2455	bch2_btree_iter_verify(iter);
2456	bch2_btree_iter_verify_entry_exit(iter);
2457	EBUG_ON(btree_iter_path(trans, iter)->level && (iter->flags & BTREE_ITER_WITH_KEY_CACHE));
2458
2459	/* extents can't span inode numbers: */
2460	if ((iter->flags & BTREE_ITER_IS_EXTENTS) &&
2461	unlikely(iter->pos.offset == KEY_OFFSET_MAX)) {
2462	if (iter->pos.inode == KEY_INODE_MAX)
2463	return bkey_s_c_null;
2464
2465	bch2_btree_iter_set_pos(iter, new_pos: bpos_nosnap_successor(p: iter->pos));
2466	}
2467
2468	search_key = btree_iter_search_key(iter);
2469	iter->path = bch2_btree_path_set_pos(trans, path: iter->path, new_pos: search_key,
2470	intent: iter->flags & BTREE_ITER_INTENT,
2471	ip: btree_iter_ip_allocated(iter));
2472
2473	ret = bch2_btree_path_traverse(trans, path: iter->path, flags: iter->flags);
2474	if (unlikely(ret)) {
2475	k = bkey_s_c_err(ret);
2476	goto out_no_locked;
2477	}
2478
2479	if ((iter->flags & BTREE_ITER_CACHED) ||
2480	!(iter->flags & (BTREE_ITER_IS_EXTENTS|BTREE_ITER_FILTER_SNAPSHOTS))) {
2481	k = bkey_s_c_null;
2482
2483	if (unlikely((iter->flags & BTREE_ITER_WITH_UPDATES) &&
2484	trans->nr_updates)) {
2485	bch2_btree_trans_peek_slot_updates(trans, iter, k: &k);
2486	if (k.k)
2487	goto out;
2488	}
2489
2490	if (unlikely(iter->flags & BTREE_ITER_WITH_JOURNAL) &&
2491	(k = btree_trans_peek_slot_journal(trans, iter)).k)
2492	goto out;
2493
2494	if (unlikely(iter->flags & BTREE_ITER_WITH_KEY_CACHE) &&
2495	(k = btree_trans_peek_key_cache(iter, pos: iter->pos)).k) {
2496	if (!bkey_err(k))
2497	iter->k = *k.k;
2498	/* We're not returning a key from iter->path: */
2499	goto out_no_locked;
2500	}
2501
2502	k = bch2_btree_path_peek_slot(path: trans->paths + iter->path, u: &iter->k);
2503	if (unlikely(!k.k))
2504	goto out_no_locked;
2505	} else {
2506	struct bpos next;
2507	struct bpos end = iter->pos;
2508
2509	if (iter->flags & BTREE_ITER_IS_EXTENTS)
2510	end.offset = U64_MAX;
2511
2512	EBUG_ON(btree_iter_path(trans, iter)->level);
2513
2514	if (iter->flags & BTREE_ITER_INTENT) {
2515	struct btree_iter iter2;
2516
2517	bch2_trans_copy_iter(&iter2, iter);
2518	k = bch2_btree_iter_peek_upto(iter: &iter2, end);
2519
2520	if (k.k && !bkey_err(k)) {
2521	swap(iter->key_cache_path, iter2.key_cache_path);
2522	iter->k = iter2.k;
2523	k.k = &iter->k;
2524	}
2525	bch2_trans_iter_exit(trans, &iter2);
2526	} else {
2527	struct bpos pos = iter->pos;
2528
2529	k = bch2_btree_iter_peek_upto(iter, end);
2530	if (unlikely(bkey_err(k)))
2531	bch2_btree_iter_set_pos(iter, new_pos: pos);
2532	else
2533	iter->pos = pos;
2534	}
2535
2536	if (unlikely(bkey_err(k)))
2537	goto out_no_locked;
2538
2539	next = k.k ? bkey_start_pos(k: k.k) : POS_MAX;
2540
2541	if (bkey_lt(l: iter->pos, r: next)) {
2542	bkey_init(k: &iter->k);
2543	iter->k.p = iter->pos;
2544
2545	if (iter->flags & BTREE_ITER_IS_EXTENTS) {
2546	bch2_key_resize(k: &iter->k,
2547	min_t(u64, KEY_SIZE_MAX,
2548	(next.inode == iter->pos.inode
2549	? next.offset
2550	: KEY_OFFSET_MAX) -
2551	iter->pos.offset));
2552	EBUG_ON(!iter->k.size);
2553	}
2554
2555	k = (struct bkey_s_c) { &iter->k, NULL };
2556	}
2557	}
2558	out:
2559	btree_path_set_should_be_locked(path: btree_iter_path(trans, iter));
2560	out_no_locked:
2561	bch2_btree_iter_verify_entry_exit(iter);
2562	bch2_btree_iter_verify(iter);
2563	ret = bch2_btree_iter_verify_ret(iter, k);
2564	if (unlikely(ret))
2565	return bkey_s_c_err(ret);
2566
2567	return k;
2568	}
2569
2570	struct bkey_s_c bch2_btree_iter_next_slot(struct btree_iter *iter)
2571	{
2572	if (!bch2_btree_iter_advance(iter))
2573	return bkey_s_c_null;
2574
2575	return bch2_btree_iter_peek_slot(iter);
2576	}
2577
2578	struct bkey_s_c bch2_btree_iter_prev_slot(struct btree_iter *iter)
2579	{
2580	if (!bch2_btree_iter_rewind(iter))
2581	return bkey_s_c_null;
2582
2583	return bch2_btree_iter_peek_slot(iter);
2584	}
2585
2586	struct bkey_s_c bch2_btree_iter_peek_and_restart_outlined(struct btree_iter *iter)
2587	{
2588	struct bkey_s_c k;
2589
2590	while (btree_trans_too_many_iters(trans: iter->trans) ||
2591	(k = bch2_btree_iter_peek_type(iter, flags: iter->flags),
2592	bch2_err_matches(bkey_err(k), BCH_ERR_transaction_restart)))
2593	bch2_trans_begin(iter->trans);
2594
2595	return k;
2596	}
2597
2598	/* new transactional stuff: */
2599
2600	#ifdef CONFIG_BCACHEFS_DEBUG
2601	static void btree_trans_verify_sorted_refs(struct btree_trans *trans)
2602	{
2603	struct btree_path *path;
2604	unsigned i;
2605
2606	BUG_ON(trans->nr_sorted != bitmap_weight(trans->paths_allocated, trans->nr_paths) - 1);
2607
2608	trans_for_each_path(trans, path, i) {
2609	BUG_ON(path->sorted_idx >= trans->nr_sorted);
2610	BUG_ON(trans->sorted[path->sorted_idx] != i);
2611	}
2612
2613	for (i = 0; i < trans->nr_sorted; i++) {
2614	unsigned idx = trans->sorted[i];
2615
2616	BUG_ON(!test_bit(idx, trans->paths_allocated));
2617	BUG_ON(trans->paths[idx].sorted_idx != i);
2618	}
2619	}
2620
2621	static void btree_trans_verify_sorted(struct btree_trans *trans)
2622	{
2623	struct btree_path *path, *prev = NULL;
2624	struct trans_for_each_path_inorder_iter iter;
2625
2626	if (!bch2_debug_check_iterators)
2627	return;
2628
2629	trans_for_each_path_inorder(trans, path, iter) {
2630	if (prev && btree_path_cmp(prev, path) > 0) {
2631	__bch2_dump_trans_paths_updates(trans, true);
2632	panic("trans paths out of order!\n");
2633	}
2634	prev = path;
2635	}
2636	}
2637	#else
2638	static inline void btree_trans_verify_sorted_refs(struct btree_trans *trans) {}
2639	static inline void btree_trans_verify_sorted(struct btree_trans *trans) {}
2640	#endif
2641
2642	void __bch2_btree_trans_sort_paths(struct btree_trans *trans)
2643	{
2644	int i, l = 0, r = trans->nr_sorted, inc = 1;
2645	bool swapped;
2646
2647	btree_trans_verify_sorted_refs(trans);
2648
2649	if (trans->paths_sorted)
2650	goto out;
2651
2652	/*
2653	* Cocktail shaker sort: this is efficient because iterators will be
2654	* mostly sorted.
2655	*/
2656	do {
2657	swapped = false;
2658
2659	for (i = inc > 0 ? l : r - 2;
2660	i + 1 < r && i >= l;
2661	i += inc) {
2662	if (btree_path_cmp(l: trans->paths + trans->sorted[i],
2663	r: trans->paths + trans->sorted[i + 1]) > 0) {
2664	swap(trans->sorted[i], trans->sorted[i + 1]);
2665	trans->paths[trans->sorted[i]].sorted_idx = i;
2666	trans->paths[trans->sorted[i + 1]].sorted_idx = i + 1;
2667	swapped = true;
2668	}
2669	}
2670
2671	if (inc > 0)
2672	--r;
2673	else
2674	l++;
2675	inc = -inc;
2676	} while (swapped);
2677
2678	trans->paths_sorted = true;
2679	out:
2680	btree_trans_verify_sorted(trans);
2681	}
2682
2683	static inline void btree_path_list_remove(struct btree_trans *trans,
2684	struct btree_path *path)
2685	{
2686	EBUG_ON(path->sorted_idx >= trans->nr_sorted);
2687	#ifdef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
2688	trans->nr_sorted--;
2689	memmove_u64s_down_small(dst: trans->sorted + path->sorted_idx,
2690	src: trans->sorted + path->sorted_idx + 1,
2691	DIV_ROUND_UP(trans->nr_sorted - path->sorted_idx,
2692	sizeof(u64) / sizeof(btree_path_idx_t)));
2693	#else
2694	array_remove_item(trans->sorted, trans->nr_sorted, path->sorted_idx);
2695	#endif
2696	for (unsigned i = path->sorted_idx; i < trans->nr_sorted; i++)
2697	trans->paths[trans->sorted[i]].sorted_idx = i;
2698	}
2699
2700	static inline void btree_path_list_add(struct btree_trans *trans,
2701	btree_path_idx_t pos,
2702	btree_path_idx_t path_idx)
2703	{
2704	struct btree_path *path = trans->paths + path_idx;
2705
2706	path->sorted_idx = pos ? trans->paths[pos].sorted_idx + 1 : trans->nr_sorted;
2707
2708	#ifdef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS
2709	memmove_u64s_up_small(dst: trans->sorted + path->sorted_idx + 1,
2710	src: trans->sorted + path->sorted_idx,
2711	DIV_ROUND_UP(trans->nr_sorted - path->sorted_idx,
2712	sizeof(u64) / sizeof(btree_path_idx_t)));
2713	trans->nr_sorted++;
2714	trans->sorted[path->sorted_idx] = path_idx;
2715	#else
2716	array_insert_item(trans->sorted, trans->nr_sorted, path->sorted_idx, path_idx);
2717	#endif
2718
2719	for (unsigned i = path->sorted_idx; i < trans->nr_sorted; i++)
2720	trans->paths[trans->sorted[i]].sorted_idx = i;
2721
2722	btree_trans_verify_sorted_refs(trans);
2723	}
2724
2725	void bch2_trans_iter_exit(struct btree_trans *trans, struct btree_iter *iter)
2726	{
2727	if (iter->update_path)
2728	bch2_path_put_nokeep(trans, path: iter->update_path,
2729	intent: iter->flags & BTREE_ITER_INTENT);
2730	if (iter->path)
2731	bch2_path_put(trans, path_idx: iter->path,
2732	intent: iter->flags & BTREE_ITER_INTENT);
2733	if (iter->key_cache_path)
2734	bch2_path_put(trans, path_idx: iter->key_cache_path,
2735	intent: iter->flags & BTREE_ITER_INTENT);
2736	iter->path = 0;
2737	iter->update_path = 0;
2738	iter->key_cache_path = 0;
2739	iter->trans = NULL;
2740	}
2741
2742	void bch2_trans_iter_init_outlined(struct btree_trans *trans,
2743	struct btree_iter *iter,
2744	enum btree_id btree_id, struct bpos pos,
2745	unsigned flags)
2746	{
2747	bch2_trans_iter_init_common(trans, iter, btree_id, pos, locks_want: 0, depth: 0,
2748	flags: bch2_btree_iter_flags(trans, btree_id, flags),
2749	_RET_IP_);
2750	}
2751
2752	void bch2_trans_node_iter_init(struct btree_trans *trans,
2753	struct btree_iter *iter,
2754	enum btree_id btree_id,
2755	struct bpos pos,
2756	unsigned locks_want,
2757	unsigned depth,
2758	unsigned flags)
2759	{
2760	flags |= BTREE_ITER_NOT_EXTENTS;
2761	flags |= __BTREE_ITER_ALL_SNAPSHOTS;
2762	flags |= BTREE_ITER_ALL_SNAPSHOTS;
2763
2764	bch2_trans_iter_init_common(trans, iter, btree_id, pos, locks_want, depth,
2765	flags: __bch2_btree_iter_flags(trans, btree_id, flags),
2766	_RET_IP_);
2767
2768	iter->min_depth = depth;
2769
2770	struct btree_path *path = btree_iter_path(trans, iter);
2771	BUG_ON(path->locks_want < min(locks_want, BTREE_MAX_DEPTH));
2772	BUG_ON(path->level != depth);
2773	BUG_ON(iter->min_depth != depth);
2774	}
2775
2776	void bch2_trans_copy_iter(struct btree_iter *dst, struct btree_iter *src)
2777	{
2778	struct btree_trans *trans = src->trans;
2779
2780	*dst = *src;
2781	#ifdef TRACK_PATH_ALLOCATED
2782	dst->ip_allocated = _RET_IP_;
2783	#endif
2784	if (src->path)
2785	__btree_path_get(path: trans->paths + src->path, intent: src->flags & BTREE_ITER_INTENT);
2786	if (src->update_path)
2787	__btree_path_get(path: trans->paths + src->update_path, intent: src->flags & BTREE_ITER_INTENT);
2788	dst->key_cache_path = 0;
2789	}
2790
2791	void *__bch2_trans_kmalloc(struct btree_trans *trans, size_t size)
2792	{
2793	struct bch_fs *c = trans->c;
2794	unsigned new_top = trans->mem_top + size;
2795	unsigned old_bytes = trans->mem_bytes;
2796	unsigned new_bytes = roundup_pow_of_two(new_top);
2797	int ret;
2798	void *new_mem;
2799	void *p;
2800
2801	WARN_ON_ONCE(new_bytes > BTREE_TRANS_MEM_MAX);
2802
2803	struct btree_transaction_stats *s = btree_trans_stats(trans);
2804	s->max_mem = max(s->max_mem, new_bytes);
2805
2806	if (trans->used_mempool) {
2807	if (trans->mem_bytes >= new_bytes)
2808	goto out_change_top;
2809
2810	/* No more space from mempool item, need malloc new one */
2811	new_mem = kmalloc(size: new_bytes, GFP_NOWAIT|__GFP_NOWARN);
2812	if (unlikely(!new_mem)) {
2813	bch2_trans_unlock(trans);
2814
2815	new_mem = kmalloc(size: new_bytes, GFP_KERNEL);
2816	if (!new_mem)
2817	return ERR_PTR(error: -BCH_ERR_ENOMEM_trans_kmalloc);
2818
2819	ret = bch2_trans_relock(trans);
2820	if (ret) {
2821	kfree(objp: new_mem);
2822	return ERR_PTR(error: ret);
2823	}
2824	}
2825	memcpy(new_mem, trans->mem, trans->mem_top);
2826	trans->used_mempool = false;
2827	mempool_free(element: trans->mem, pool: &c->btree_trans_mem_pool);
2828	goto out_new_mem;
2829	}
2830
2831	new_mem = krealloc(objp: trans->mem, new_size: new_bytes, GFP_NOWAIT|__GFP_NOWARN);
2832	if (unlikely(!new_mem)) {
2833	bch2_trans_unlock(trans);
2834
2835	new_mem = krealloc(objp: trans->mem, new_size: new_bytes, GFP_KERNEL);
2836	if (!new_mem && new_bytes <= BTREE_TRANS_MEM_MAX) {
2837	new_mem = mempool_alloc(pool: &c->btree_trans_mem_pool, GFP_KERNEL);
2838	new_bytes = BTREE_TRANS_MEM_MAX;
2839	memcpy(new_mem, trans->mem, trans->mem_top);
2840	trans->used_mempool = true;
2841	kfree(objp: trans->mem);
2842	}
2843
2844	if (!new_mem)
2845	return ERR_PTR(error: -BCH_ERR_ENOMEM_trans_kmalloc);
2846
2847	trans->mem = new_mem;
2848	trans->mem_bytes = new_bytes;
2849
2850	ret = bch2_trans_relock(trans);
2851	if (ret)
2852	return ERR_PTR(error: ret);
2853	}
2854	out_new_mem:
2855	trans->mem = new_mem;
2856	trans->mem_bytes = new_bytes;
2857
2858	if (old_bytes) {
2859	trace_and_count(c, trans_restart_mem_realloced, trans, _RET_IP_, new_bytes);
2860	return ERR_PTR(error: btree_trans_restart(trans, err: BCH_ERR_transaction_restart_mem_realloced));
2861	}
2862	out_change_top:
2863	p = trans->mem + trans->mem_top;
2864	trans->mem_top += size;
2865	memset(p, 0, size);
2866	return p;
2867	}
2868
2869	static inline void check_srcu_held_too_long(struct btree_trans *trans)
2870	{
2871	WARN(trans->srcu_held && time_after(jiffies, trans->srcu_lock_time + HZ * 10),
2872	"btree trans held srcu lock (delaying memory reclaim) for %lu seconds",
2873	(jiffies - trans->srcu_lock_time) / HZ);
2874	}
2875
2876	void bch2_trans_srcu_unlock(struct btree_trans *trans)
2877	{
2878	if (trans->srcu_held) {
2879	struct bch_fs *c = trans->c;
2880	struct btree_path *path;
2881	unsigned i;
2882
2883	trans_for_each_path(trans, path, i)
2884	if (path->cached && !btree_node_locked(path, level: 0))
2885	path->l[0].b = ERR_PTR(error: -BCH_ERR_no_btree_node_srcu_reset);
2886
2887	check_srcu_held_too_long(trans);
2888	srcu_read_unlock(ssp: &c->btree_trans_barrier, idx: trans->srcu_idx);
2889	trans->srcu_held = false;
2890	}
2891	}
2892
2893	static void bch2_trans_srcu_lock(struct btree_trans *trans)
2894	{
2895	if (!trans->srcu_held) {
2896	trans->srcu_idx = srcu_read_lock(ssp: &trans->c->btree_trans_barrier);
2897	trans->srcu_lock_time = jiffies;
2898	trans->srcu_held = true;
2899	}
2900	}
2901
2902	/**
2903	* bch2_trans_begin() - reset a transaction after a interrupted attempt
2904	* @trans: transaction to reset
2905	*
2906	* Returns: current restart counter, to be used with trans_was_restarted()
2907	*
2908	* While iterating over nodes or updating nodes a attempt to lock a btree node
2909	* may return BCH_ERR_transaction_restart when the trylock fails. When this
2910	* occurs bch2_trans_begin() should be called and the transaction retried.
2911	*/
2912	u32 bch2_trans_begin(struct btree_trans *trans)
2913	{
2914	struct btree_path *path;
2915	unsigned i;
2916	u64 now;
2917
2918	bch2_trans_reset_updates(trans);
2919
2920	trans->restart_count++;
2921	trans->mem_top = 0;
2922	trans->journal_entries = NULL;
2923
2924	trans_for_each_path(trans, path, i) {
2925	path->should_be_locked = false;
2926
2927	/*
2928	* If the transaction wasn't restarted, we're presuming to be
2929	* doing something new: dont keep iterators excpt the ones that
2930	* are in use - except for the subvolumes btree:
2931	*/
2932	if (!trans->restarted && path->btree_id != BTREE_ID_subvolumes)
2933	path->preserve = false;
2934
2935	/*
2936	* XXX: we probably shouldn't be doing this if the transaction
2937	* was restarted, but currently we still overflow transaction
2938	* iterators if we do that
2939	*/
2940	if (!path->ref && !path->preserve)
2941	__bch2_path_free(trans, path: i);
2942	else
2943	path->preserve = false;
2944	}
2945
2946	now = local_clock();
2947
2948	if (!IS_ENABLED(CONFIG_BCACHEFS_NO_LATENCY_ACCT) &&
2949	time_after64(now, trans->last_begin_time + 10))
2950	__bch2_time_stats_update(stats: &btree_trans_stats(trans)->duration,
2951	trans->last_begin_time, now);
2952
2953	if (!trans->restarted &&
2954	(need_resched() ||
2955	time_after64(now, trans->last_begin_time + BTREE_TRANS_MAX_LOCK_HOLD_TIME_NS))) {
2956	drop_locks_do(trans, (cond_resched(), 0));
2957	now = local_clock();
2958	}
2959	trans->last_begin_time = now;
2960
2961	if (unlikely(trans->srcu_held &&
2962	time_after(jiffies, trans->srcu_lock_time + msecs_to_jiffies(10))))
2963	bch2_trans_srcu_unlock(trans);
2964
2965	trans->last_begin_ip = _RET_IP_;
2966	if (trans->restarted) {
2967	bch2_btree_path_traverse_all(trans);
2968	trans->notrace_relock_fail = false;
2969	}
2970
2971	return trans->restart_count;
2972	}
2973
2974	const char *bch2_btree_transaction_fns[BCH_TRANSACTIONS_NR] = { "(unknown)" };
2975
2976	unsigned bch2_trans_get_fn_idx(const char *fn)
2977	{
2978	for (unsigned i = 0; i < ARRAY_SIZE(bch2_btree_transaction_fns); i++)
2979	if (!bch2_btree_transaction_fns[i] ||
2980	bch2_btree_transaction_fns[i] == fn) {
2981	bch2_btree_transaction_fns[i] = fn;
2982	return i;
2983	}
2984
2985	pr_warn_once("BCH_TRANSACTIONS_NR not big enough!");
2986	return 0;
2987	}
2988
2989	struct btree_trans *__bch2_trans_get(struct bch_fs *c, unsigned fn_idx)
2990	__acquires(&c->btree_trans_barrier)
2991	{
2992	struct btree_trans *trans;
2993
2994	if (IS_ENABLED(__KERNEL__)) {
2995	trans = this_cpu_xchg(c->btree_trans_bufs->trans, NULL);
2996	if (trans) {
2997	memset(trans, 0, offsetof(struct btree_trans, list));
2998	goto got_trans;
2999	}
3000	}
3001
3002	trans = mempool_alloc(pool: &c->btree_trans_pool, GFP_NOFS);
3003	memset(trans, 0, sizeof(*trans));
3004	closure_init_stack(cl: &trans->ref);
3005
3006	seqmutex_lock(lock: &c->btree_trans_lock);
3007	if (IS_ENABLED(CONFIG_BCACHEFS_DEBUG)) {
3008	struct btree_trans *pos;
3009	pid_t pid = current->pid;
3010
3011	trans->locking_wait.task = current;
3012
3013	list_for_each_entry(pos, &c->btree_trans_list, list) {
3014	struct task_struct *pos_task = READ_ONCE(pos->locking_wait.task);
3015	/*
3016	* We'd much prefer to be stricter here and completely
3017	* disallow multiple btree_trans in the same thread -
3018	* but the data move path calls bch2_write when we
3019	* already have a btree_trans initialized.
3020	*/
3021	BUG_ON(pos_task &&
3022	pid == pos_task->pid &&
3023	bch2_trans_locked(pos));
3024
3025	if (pos_task && pid < pos_task->pid) {
3026	list_add_tail(new: &trans->list, head: &pos->list);
3027	goto list_add_done;
3028	}
3029	}
3030	}
3031	list_add_tail(new: &trans->list, head: &c->btree_trans_list);
3032	list_add_done:
3033	seqmutex_unlock(lock: &c->btree_trans_lock);
3034	got_trans:
3035	trans->c = c;
3036	trans->last_begin_time = local_clock();
3037	trans->fn_idx = fn_idx;
3038	trans->locking_wait.task = current;
3039	trans->journal_replay_not_finished =
3040	unlikely(!test_bit(JOURNAL_REPLAY_DONE, &c->journal.flags)) &&
3041	atomic_inc_not_zero(v: &c->journal_keys.ref);
3042	trans->nr_paths = ARRAY_SIZE(trans->_paths);
3043	trans->paths_allocated = trans->_paths_allocated;
3044	trans->sorted = trans->_sorted;
3045	trans->paths = trans->_paths;
3046	trans->updates = trans->_updates;
3047
3048	*trans_paths_nr(paths: trans->paths) = BTREE_ITER_INITIAL;
3049
3050	trans->paths_allocated[0] = 1;
3051
3052	if (fn_idx < BCH_TRANSACTIONS_NR) {
3053	trans->fn = bch2_btree_transaction_fns[fn_idx];
3054
3055	struct btree_transaction_stats *s = &c->btree_transaction_stats[fn_idx];
3056
3057	if (s->max_mem) {
3058	unsigned expected_mem_bytes = roundup_pow_of_two(s->max_mem);
3059
3060	trans->mem = kmalloc(size: expected_mem_bytes, GFP_KERNEL);
3061	if (likely(trans->mem))
3062	trans->mem_bytes = expected_mem_bytes;
3063	}
3064
3065	trans->nr_paths_max = s->nr_max_paths;
3066	trans->journal_entries_size = s->journal_entries_size;
3067	}
3068
3069	trans->srcu_idx = srcu_read_lock(ssp: &c->btree_trans_barrier);
3070	trans->srcu_lock_time = jiffies;
3071	trans->srcu_held = true;
3072	return trans;
3073	}
3074
3075	static void check_btree_paths_leaked(struct btree_trans *trans)
3076	{
3077	#ifdef CONFIG_BCACHEFS_DEBUG
3078	struct bch_fs *c = trans->c;
3079	struct btree_path *path;
3080	unsigned i;
3081
3082	trans_for_each_path(trans, path, i)
3083	if (path->ref)
3084	goto leaked;
3085	return;
3086	leaked:
3087	bch_err(c, "btree paths leaked from %s!", trans->fn);
3088	trans_for_each_path(trans, path, i)
3089	if (path->ref)
3090	printk(KERN_ERR " btree %s %pS\n",
3091	bch2_btree_id_str(path->btree_id),
3092	(void *) path->ip_allocated);
3093	/* Be noisy about this: */
3094	bch2_fatal_error(c);
3095	#endif
3096	}
3097
3098	void bch2_trans_put(struct btree_trans *trans)
3099	__releases(&c->btree_trans_barrier)
3100	{
3101	struct bch_fs *c = trans->c;
3102
3103	bch2_trans_unlock(trans);
3104
3105	trans_for_each_update(trans, i)
3106	__btree_path_put(path: trans->paths + i->path, intent: true);
3107	trans->nr_updates = 0;
3108	trans->locking_wait.task = NULL;
3109
3110	check_btree_paths_leaked(trans);
3111
3112	if (trans->srcu_held) {
3113	check_srcu_held_too_long(trans);
3114	srcu_read_unlock(ssp: &c->btree_trans_barrier, idx: trans->srcu_idx);
3115	}
3116
3117	if (trans->fs_usage_deltas) {
3118	if (trans->fs_usage_deltas->size + sizeof(trans->fs_usage_deltas) ==
3119	REPLICAS_DELTA_LIST_MAX)
3120	mempool_free(element: trans->fs_usage_deltas,
3121	pool: &c->replicas_delta_pool);
3122	else
3123	kfree(objp: trans->fs_usage_deltas);
3124	}
3125
3126	if (unlikely(trans->journal_replay_not_finished))
3127	bch2_journal_keys_put(c);
3128
3129	unsigned long *paths_allocated = trans->paths_allocated;
3130	trans->paths_allocated = NULL;
3131	trans->paths = NULL;
3132
3133	if (paths_allocated != trans->_paths_allocated)
3134	kvfree_rcu_mightsleep(paths_allocated);
3135
3136	if (trans->used_mempool)
3137	mempool_free(element: trans->mem, pool: &c->btree_trans_mem_pool);
3138	else
3139	kfree(objp: trans->mem);
3140
3141	/* Userspace doesn't have a real percpu implementation: */
3142	if (IS_ENABLED(__KERNEL__))
3143	trans = this_cpu_xchg(c->btree_trans_bufs->trans, trans);
3144
3145	if (trans) {
3146	closure_sync(cl: &trans->ref);
3147
3148	seqmutex_lock(lock: &c->btree_trans_lock);
3149	list_del(entry: &trans->list);
3150	seqmutex_unlock(lock: &c->btree_trans_lock);
3151
3152	mempool_free(element: trans, pool: &c->btree_trans_pool);
3153	}
3154	}
3155
3156	static void __maybe_unused
3157	bch2_btree_bkey_cached_common_to_text(struct printbuf *out,
3158	struct btree_bkey_cached_common *b)
3159	{
3160	struct six_lock_count c = six_lock_counts(&b->lock);
3161	struct task_struct *owner;
3162	pid_t pid;
3163
3164	rcu_read_lock();
3165	owner = READ_ONCE(b->lock.owner);
3166	pid = owner ? owner->pid : 0;
3167	rcu_read_unlock();
3168
3169	prt_tab(out);
3170	prt_printf(out, "%px %c l=%u %s:", b, b->cached ? 'c' : 'b',
3171	b->level, bch2_btree_id_str(b->btree_id));
3172	bch2_bpos_to_text(out, btree_node_pos(b));
3173
3174	prt_tab(out);
3175	prt_printf(out, " locks %u:%u:%u held by pid %u",
3176	c.n[0], c.n[1], c.n[2], pid);
3177	}
3178
3179	void bch2_btree_trans_to_text(struct printbuf *out, struct btree_trans *trans)
3180	{
3181	struct btree_bkey_cached_common *b;
3182	static char lock_types[] = { 'r', 'i', 'w' };
3183	struct task_struct *task = READ_ONCE(trans->locking_wait.task);
3184	unsigned l, idx;
3185
3186	/* before rcu_read_lock(): */
3187	bch2_printbuf_make_room(out, 4096);
3188
3189	if (!out->nr_tabstops) {
3190	printbuf_tabstop_push(out, 16);
3191	printbuf_tabstop_push(out, 32);
3192	}
3193
3194	prt_printf(out, "%i %s\n", task ? task->pid : 0, trans->fn);
3195
3196	/* trans->paths is rcu protected vs. freeing */
3197	rcu_read_lock();
3198	out->atomic++;
3199
3200	struct btree_path *paths = rcu_dereference(trans->paths);
3201	if (!paths)
3202	goto out;
3203
3204	unsigned long *paths_allocated = trans_paths_allocated(paths);
3205
3206	trans_for_each_path_idx_from(paths_allocated, *trans_paths_nr(paths), idx, 1) {
3207	struct btree_path *path = paths + idx;
3208	if (!path->nodes_locked)
3209	continue;
3210
3211	prt_printf(out, " path %u %c l=%u %s:",
3212	idx,
3213	path->cached ? 'c' : 'b',
3214	path->level,
3215	bch2_btree_id_str(path->btree_id));
3216	bch2_bpos_to_text(out, path->pos);
3217	prt_newline(out);
3218
3219	for (l = 0; l < BTREE_MAX_DEPTH; l++) {
3220	if (btree_node_locked(path, level: l) &&
3221	!IS_ERR_OR_NULL(ptr: b = (void *) READ_ONCE(path->l[l].b))) {
3222	prt_printf(out, " %c l=%u ",
3223	lock_types[btree_node_locked_type(path, l)], l);
3224	bch2_btree_bkey_cached_common_to_text(out, b);
3225	prt_newline(out);
3226	}
3227	}
3228	}
3229
3230	b = READ_ONCE(trans->locking);
3231	if (b) {
3232	prt_printf(out, " blocked for %lluus on",
3233	div_u64(local_clock() - trans->locking_wait.start_time,
3234	1000));
3235	prt_newline(out);
3236	prt_printf(out, " %c", lock_types[trans->locking_wait.lock_want]);
3237	bch2_btree_bkey_cached_common_to_text(out, b);
3238	prt_newline(out);
3239	}
3240	out:
3241	--out->atomic;
3242	rcu_read_unlock();
3243	}
3244
3245	void bch2_fs_btree_iter_exit(struct bch_fs *c)
3246	{
3247	struct btree_transaction_stats *s;
3248	struct btree_trans *trans;
3249	int cpu;
3250
3251	if (c->btree_trans_bufs)
3252	for_each_possible_cpu(cpu) {
3253	struct btree_trans *trans =
3254	per_cpu_ptr(c->btree_trans_bufs, cpu)->trans;
3255
3256	if (trans) {
3257	closure_sync(cl: &trans->ref);
3258
3259	seqmutex_lock(lock: &c->btree_trans_lock);
3260	list_del(entry: &trans->list);
3261	seqmutex_unlock(lock: &c->btree_trans_lock);
3262	}
3263	kfree(objp: trans);
3264	}
3265	free_percpu(pdata: c->btree_trans_bufs);
3266
3267	trans = list_first_entry_or_null(&c->btree_trans_list, struct btree_trans, list);
3268	if (trans)
3269	panic(fmt: "%s leaked btree_trans\n", trans->fn);
3270
3271	for (s = c->btree_transaction_stats;
3272	s < c->btree_transaction_stats + ARRAY_SIZE(c->btree_transaction_stats);
3273	s++) {
3274	kfree(objp: s->max_paths_text);
3275	bch2_time_stats_exit(&s->lock_hold_times);
3276	}
3277
3278	if (c->btree_trans_barrier_initialized)
3279	cleanup_srcu_struct(ssp: &c->btree_trans_barrier);
3280	mempool_exit(pool: &c->btree_trans_mem_pool);
3281	mempool_exit(pool: &c->btree_trans_pool);
3282	}
3283
3284	void bch2_fs_btree_iter_init_early(struct bch_fs *c)
3285	{
3286	struct btree_transaction_stats *s;
3287
3288	for (s = c->btree_transaction_stats;
3289	s < c->btree_transaction_stats + ARRAY_SIZE(c->btree_transaction_stats);
3290	s++) {
3291	bch2_time_stats_init(&s->duration);
3292	bch2_time_stats_init(&s->lock_hold_times);
3293	mutex_init(&s->lock);
3294	}
3295
3296	INIT_LIST_HEAD(list: &c->btree_trans_list);
3297	seqmutex_init(&c->btree_trans_lock);
3298	}
3299
3300	int bch2_fs_btree_iter_init(struct bch_fs *c)
3301	{
3302	int ret;
3303
3304	c->btree_trans_bufs = alloc_percpu(struct btree_trans_buf);
3305	if (!c->btree_trans_bufs)
3306	return -ENOMEM;
3307
3308	ret = mempool_init_kmalloc_pool(pool: &c->btree_trans_pool, min_nr: 1,
3309	size: sizeof(struct btree_trans)) ?:
3310	mempool_init_kmalloc_pool(pool: &c->btree_trans_mem_pool, min_nr: 1,
3311	BTREE_TRANS_MEM_MAX) ?:
3312	init_srcu_struct(&c->btree_trans_barrier);
3313	if (!ret)
3314	c->btree_trans_barrier_initialized = true;
3315	return ret;
3316	}
3317