brintos / linux-shallow public Read only

1// SPDX-License-Identifier: GPL-2.02 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 24static inline void btree_path_list_remove(struct btree_trans *, struct btree_path *);25static inline void btree_path_list_add(struct btree_trans *,26			btree_path_idx_t, btree_path_idx_t);27 28static inline unsigned long btree_iter_ip_allocated(struct btree_iter *iter)29{30#ifdef TRACK_PATH_ALLOCATED31	return iter->ip_allocated;32#else33	return 0;34#endif35}36 37static btree_path_idx_t btree_path_alloc(struct btree_trans *, btree_path_idx_t);38static void bch2_trans_srcu_lock(struct btree_trans *);39 40static 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->pos,	r_pos) ?:52		-cmp_int(l->level,	r_level);53}54 55static 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->cached, r->pos, r->level);59}60 61static 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 74static 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 87static 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(pos, POS_MAX))93		pos = bkey_successor(iter, pos);94	return pos;95}96 97static inline bool btree_path_pos_before_node(struct btree_path *path,98					      struct btree *b)99{100	return bpos_lt(path->pos, b->data->min_key);101}102 103static inline bool btree_path_pos_after_node(struct btree_path *path,104					     struct btree *b)105{106	return bpos_gt(path->pos, b->key.k.p);107}108 109static 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_DEBUG120 121static 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, 0);126 127	if (!bch2_btree_node_relock(trans, path, 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, 0);136}137 138static 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 = level177		? 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(&l->iter, l->b);180 181	if (p && bkey_iter_pos_cmp(l->b, p, &path->pos) >= 0) {182		msg = "before";183		goto err;184	}185 186	if (k && bkey_iter_pos_cmp(l->b, k, &path->pos) < 0) {187		msg = "after";188		goto err;189	}190 191	if (!locked)192		btree_node_unlock(trans, path, level);193	return;194err:195	bch2_bpos_to_text(&buf1, path->pos);196 197	if (p) {198		struct bkey uk = bkey_unpack_key(l->b, 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(l->b, k);207 208		bch2_bkey_to_text(&buf3, &uk);209	} else {210		prt_printf(&buf3, "(none)");211	}212 213	panic("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 220static void bch2_btree_path_verify(struct btree_trans *trans,221				   struct btree_path *path)222{223	struct bch_fs *c = trans->c;224 225	for (unsigned i = 0; i < (!path->cached ? BTREE_MAX_DEPTH : 1); i++) {226		if (!path->l[i].b) {227			BUG_ON(!path->cached &&228			       bch2_btree_id_root(c, path->btree_id)->b->c.level > i);229			break;230		}231 232		bch2_btree_path_verify_level(trans, path, i);233	}234 235	bch2_btree_path_verify_locks(path);236}237 238void bch2_trans_verify_paths(struct btree_trans *trans)239{240	struct btree_path *path;241	unsigned iter;242 243	trans_for_each_path(trans, path, iter)244		bch2_btree_path_verify(trans, path);245}246 247static void bch2_btree_iter_verify(struct btree_iter *iter)248{249	struct btree_trans *trans = iter->trans;250 251	BUG_ON(!!(iter->flags & BTREE_ITER_cached) != btree_iter_path(trans, iter)->cached);252 253	BUG_ON((iter->flags & BTREE_ITER_is_extents) &&254	       (iter->flags & BTREE_ITER_all_snapshots));255 256	BUG_ON(!(iter->flags & BTREE_ITER_snapshot_field) &&257	       (iter->flags & BTREE_ITER_all_snapshots) &&258	       !btree_type_has_snapshot_field(iter->btree_id));259 260	if (iter->update_path)261		bch2_btree_path_verify(trans, &trans->paths[iter->update_path]);262	bch2_btree_path_verify(trans, btree_iter_path(trans, iter));263}264 265static void bch2_btree_iter_verify_entry_exit(struct btree_iter *iter)266{267	BUG_ON((iter->flags & BTREE_ITER_filter_snapshots) &&268	       !iter->pos.snapshot);269 270	BUG_ON(!(iter->flags & BTREE_ITER_all_snapshots) &&271	       iter->pos.snapshot != iter->snapshot);272 273	BUG_ON(bkey_lt(iter->pos, bkey_start_pos(&iter->k)) ||274	       bkey_gt(iter->pos, iter->k.p));275}276 277static int bch2_btree_iter_verify_ret(struct btree_iter *iter, struct bkey_s_c k)278{279	struct btree_trans *trans = iter->trans;280	struct btree_iter copy;281	struct bkey_s_c prev;282	int ret = 0;283 284	if (!bch2_debug_check_iterators)285		return 0;286 287	if (!(iter->flags & BTREE_ITER_filter_snapshots))288		return 0;289 290	if (bkey_err(k) || !k.k)291		return 0;292 293	BUG_ON(!bch2_snapshot_is_ancestor(trans->c,294					  iter->snapshot,295					  k.k->p.snapshot));296 297	bch2_trans_iter_init(trans, &copy, iter->btree_id, iter->pos,298			     BTREE_ITER_nopreserve|299			     BTREE_ITER_all_snapshots);300	prev = bch2_btree_iter_prev(&copy);301	if (!prev.k)302		goto out;303 304	ret = bkey_err(prev);305	if (ret)306		goto out;307 308	if (bkey_eq(prev.k->p, k.k->p) &&309	    bch2_snapshot_is_ancestor(trans->c, iter->snapshot,310				      prev.k->p.snapshot) > 0) {311		struct printbuf buf1 = PRINTBUF, buf2 = PRINTBUF;312 313		bch2_bkey_to_text(&buf1, k.k);314		bch2_bkey_to_text(&buf2, prev.k);315 316		panic("iter snap %u\n"317		      "k    %s\n"318		      "prev %s\n",319		      iter->snapshot,320		      buf1.buf, buf2.buf);321	}322out:323	bch2_trans_iter_exit(trans, &copy);324	return ret;325}326 327void bch2_assert_pos_locked(struct btree_trans *trans, enum btree_id id,328			    struct bpos pos)329{330	bch2_trans_verify_not_unlocked(trans);331 332	struct btree_path *path;333	struct trans_for_each_path_inorder_iter iter;334	struct printbuf buf = PRINTBUF;335 336	btree_trans_sort_paths(trans);337 338	trans_for_each_path_inorder(trans, path, iter) {339		if (path->btree_id != id ||340		    !btree_node_locked(path, 0) ||341		    !path->should_be_locked)342			continue;343 344		if (!path->cached) {345			if (bkey_ge(pos, path->l[0].b->data->min_key) &&346			    bkey_le(pos, path->l[0].b->key.k.p))347				return;348		} else {349			if (bkey_eq(pos, path->pos))350				return;351		}352	}353 354	bch2_dump_trans_paths_updates(trans);355	bch2_bpos_to_text(&buf, pos);356 357	panic("not locked: %s %s\n", bch2_btree_id_str(id), buf.buf);358}359 360#else361 362static inline void bch2_btree_path_verify_level(struct btree_trans *trans,363						struct btree_path *path, unsigned l) {}364static inline void bch2_btree_path_verify(struct btree_trans *trans,365					  struct btree_path *path) {}366static inline void bch2_btree_iter_verify(struct btree_iter *iter) {}367static inline void bch2_btree_iter_verify_entry_exit(struct btree_iter *iter) {}368static inline int bch2_btree_iter_verify_ret(struct btree_iter *iter, struct bkey_s_c k) { return 0; }369 370#endif371 372/* Btree path: fixups after btree updates */373 374static void btree_node_iter_set_set_pos(struct btree_node_iter *iter,375					struct btree *b,376					struct bset_tree *t,377					struct bkey_packed *k)378{379	struct btree_node_iter_set *set;380 381	btree_node_iter_for_each(iter, set)382		if (set->end == t->end_offset) {383			set->k = __btree_node_key_to_offset(b, k);384			bch2_btree_node_iter_sort(iter, b);385			return;386		}387 388	bch2_btree_node_iter_push(iter, b, k, btree_bkey_last(b, t));389}390 391static void __bch2_btree_path_fix_key_modified(struct btree_path *path,392					       struct btree *b,393					       struct bkey_packed *where)394{395	struct btree_path_level *l = &path->l[b->c.level];396 397	if (where != bch2_btree_node_iter_peek_all(&l->iter, l->b))398		return;399 400	if (bkey_iter_pos_cmp(l->b, where, &path->pos) < 0)401		bch2_btree_node_iter_advance(&l->iter, l->b);402}403 404void bch2_btree_path_fix_key_modified(struct btree_trans *trans,405				      struct btree *b,406				      struct bkey_packed *where)407{408	struct btree_path *path;409	unsigned i;410 411	trans_for_each_path_with_node(trans, b, path, i) {412		__bch2_btree_path_fix_key_modified(path, b, where);413		bch2_btree_path_verify_level(trans, path, b->c.level);414	}415}416 417static void __bch2_btree_node_iter_fix(struct btree_path *path,418				       struct btree *b,419				       struct btree_node_iter *node_iter,420				       struct bset_tree *t,421				       struct bkey_packed *where,422				       unsigned clobber_u64s,423				       unsigned new_u64s)424{425	const struct bkey_packed *end = btree_bkey_last(b, t);426	struct btree_node_iter_set *set;427	unsigned offset = __btree_node_key_to_offset(b, where);428	int shift = new_u64s - clobber_u64s;429	unsigned old_end = t->end_offset - shift;430	unsigned orig_iter_pos = node_iter->data[0].k;431	bool iter_current_key_modified =432		orig_iter_pos >= offset &&433		orig_iter_pos <= offset + clobber_u64s;434 435	btree_node_iter_for_each(node_iter, set)436		if (set->end == old_end)437			goto found;438 439	/* didn't find the bset in the iterator - might have to readd it: */440	if (new_u64s &&441	    bkey_iter_pos_cmp(b, where, &path->pos) >= 0) {442		bch2_btree_node_iter_push(node_iter, b, where, end);443		goto fixup_done;444	} else {445		/* Iterator is after key that changed */446		return;447	}448found:449	set->end = t->end_offset;450 451	/* Iterator hasn't gotten to the key that changed yet: */452	if (set->k < offset)453		return;454 455	if (new_u64s &&456	    bkey_iter_pos_cmp(b, where, &path->pos) >= 0) {457		set->k = offset;458	} else if (set->k < offset + clobber_u64s) {459		set->k = offset + new_u64s;460		if (set->k == set->end)461			bch2_btree_node_iter_set_drop(node_iter, set);462	} else {463		/* Iterator is after key that changed */464		set->k = (int) set->k + shift;465		return;466	}467 468	bch2_btree_node_iter_sort(node_iter, b);469fixup_done:470	if (node_iter->data[0].k != orig_iter_pos)471		iter_current_key_modified = true;472 473	/*474	 * When a new key is added, and the node iterator now points to that475	 * key, the iterator might have skipped past deleted keys that should476	 * come after the key the iterator now points to. We have to rewind to477	 * before those deleted keys - otherwise478	 * bch2_btree_node_iter_prev_all() breaks:479	 */480	if (!bch2_btree_node_iter_end(node_iter) &&481	    iter_current_key_modified &&482	    b->c.level) {483		struct bkey_packed *k, *k2, *p;484 485		k = bch2_btree_node_iter_peek_all(node_iter, b);486 487		for_each_bset(b, t) {488			bool set_pos = false;489 490			if (node_iter->data[0].end == t->end_offset)491				continue;492 493			k2 = bch2_btree_node_iter_bset_pos(node_iter, b, t);494 495			while ((p = bch2_bkey_prev_all(b, t, k2)) &&496			       bkey_iter_cmp(b, k, p) < 0) {497				k2 = p;498				set_pos = true;499			}500 501			if (set_pos)502				btree_node_iter_set_set_pos(node_iter,503							    b, t, k2);504		}505	}506}507 508void bch2_btree_node_iter_fix(struct btree_trans *trans,509			      struct btree_path *path,510			      struct btree *b,511			      struct btree_node_iter *node_iter,512			      struct bkey_packed *where,513			      unsigned clobber_u64s,514			      unsigned new_u64s)515{516	struct bset_tree *t = bch2_bkey_to_bset_inlined(b, where);517	struct btree_path *linked;518	unsigned i;519 520	if (node_iter != &path->l[b->c.level].iter) {521		__bch2_btree_node_iter_fix(path, b, node_iter, t,522					   where, clobber_u64s, new_u64s);523 524		if (bch2_debug_check_iterators)525			bch2_btree_node_iter_verify(node_iter, b);526	}527 528	trans_for_each_path_with_node(trans, b, linked, i) {529		__bch2_btree_node_iter_fix(linked, b,530					   &linked->l[b->c.level].iter, t,531					   where, clobber_u64s, new_u64s);532		bch2_btree_path_verify_level(trans, linked, b->c.level);533	}534}535 536/* Btree path level: pointer to a particular btree node and node iter */537 538static inline struct bkey_s_c __btree_iter_unpack(struct bch_fs *c,539						  struct btree_path_level *l,540						  struct bkey *u,541						  struct bkey_packed *k)542{543	if (unlikely(!k)) {544		/*545		 * signal to bch2_btree_iter_peek_slot() that we're currently at546		 * a hole547		 */548		u->type = KEY_TYPE_deleted;549		return bkey_s_c_null;550	}551 552	return bkey_disassemble(l->b, k, u);553}554 555static inline struct bkey_s_c btree_path_level_peek_all(struct bch_fs *c,556							struct btree_path_level *l,557							struct bkey *u)558{559	return __btree_iter_unpack(c, l, u,560			bch2_btree_node_iter_peek_all(&l->iter, l->b));561}562 563static inline struct bkey_s_c btree_path_level_peek(struct btree_trans *trans,564						    struct btree_path *path,565						    struct btree_path_level *l,566						    struct bkey *u)567{568	struct bkey_s_c k = __btree_iter_unpack(trans->c, l, u,569			bch2_btree_node_iter_peek(&l->iter, l->b));570 571	path->pos = k.k ? k.k->p : l->b->key.k.p;572	trans->paths_sorted = false;573	bch2_btree_path_verify_level(trans, path, l - path->l);574	return k;575}576 577static inline struct bkey_s_c btree_path_level_prev(struct btree_trans *trans,578						    struct btree_path *path,579						    struct btree_path_level *l,580						    struct bkey *u)581{582	struct bkey_s_c k = __btree_iter_unpack(trans->c, l, u,583			bch2_btree_node_iter_prev(&l->iter, l->b));584 585	path->pos = k.k ? k.k->p : l->b->data->min_key;586	trans->paths_sorted = false;587	bch2_btree_path_verify_level(trans, path, l - path->l);588	return k;589}590 591static inline bool btree_path_advance_to_pos(struct btree_path *path,592					     struct btree_path_level *l,593					     int max_advance)594{595	struct bkey_packed *k;596	int nr_advanced = 0;597 598	while ((k = bch2_btree_node_iter_peek_all(&l->iter, l->b)) &&599	       bkey_iter_pos_cmp(l->b, k, &path->pos) < 0) {600		if (max_advance > 0 && nr_advanced >= max_advance)601			return false;602 603		bch2_btree_node_iter_advance(&l->iter, l->b);604		nr_advanced++;605	}606 607	return true;608}609 610static inline void __btree_path_level_init(struct btree_path *path,611					   unsigned level)612{613	struct btree_path_level *l = &path->l[level];614 615	bch2_btree_node_iter_init(&l->iter, l->b, &path->pos);616 617	/*618	 * Iterators to interior nodes should always be pointed at the first non619	 * whiteout:620	 */621	if (level)622		bch2_btree_node_iter_peek(&l->iter, l->b);623}624 625void bch2_btree_path_level_init(struct btree_trans *trans,626				struct btree_path *path,627				struct btree *b)628{629	BUG_ON(path->cached);630 631	EBUG_ON(!btree_path_pos_in_node(path, b));632 633	path->l[b->c.level].lock_seq = six_lock_seq(&b->c.lock);634	path->l[b->c.level].b = b;635	__btree_path_level_init(path, b->c.level);636}637 638/* Btree path: fixups after btree node updates: */639 640static void bch2_trans_revalidate_updates_in_node(struct btree_trans *trans, struct btree *b)641{642	struct bch_fs *c = trans->c;643 644	trans_for_each_update(trans, i)645		if (!i->cached &&646		    i->level	== b->c.level &&647		    i->btree_id	== b->c.btree_id &&648		    bpos_cmp(i->k->k.p, b->data->min_key) >= 0 &&649		    bpos_cmp(i->k->k.p, b->data->max_key) <= 0) {650			i->old_v = bch2_btree_path_peek_slot(trans->paths + i->path, &i->old_k).v;651 652			if (unlikely(trans->journal_replay_not_finished)) {653				struct bkey_i *j_k =654					bch2_journal_keys_peek_slot(c, i->btree_id, i->level,655								    i->k->k.p);656 657				if (j_k) {658					i->old_k = j_k->k;659					i->old_v = &j_k->v;660				}661			}662		}663}664 665/*666 * A btree node is being replaced - update the iterator to point to the new667 * node:668 */669void bch2_trans_node_add(struct btree_trans *trans,670			 struct btree_path *path,671			 struct btree *b)672{673	struct btree_path *prev;674 675	BUG_ON(!btree_path_pos_in_node(path, b));676 677	while ((prev = prev_btree_path(trans, path)) &&678	       btree_path_pos_in_node(prev, b))679		path = prev;680 681	for (;682	     path && btree_path_pos_in_node(path, b);683	     path = next_btree_path(trans, path))684		if (path->uptodate == BTREE_ITER_UPTODATE && !path->cached) {685			enum btree_node_locked_type t =686				btree_lock_want(path, b->c.level);687 688			if (t != BTREE_NODE_UNLOCKED) {689				btree_node_unlock(trans, path, b->c.level);690				six_lock_increment(&b->c.lock, (enum six_lock_type) t);691				mark_btree_node_locked(trans, path, b->c.level, t);692			}693 694			bch2_btree_path_level_init(trans, path, b);695		}696 697	bch2_trans_revalidate_updates_in_node(trans, b);698}699 700/*701 * A btree node has been modified in such a way as to invalidate iterators - fix702 * them:703 */704void bch2_trans_node_reinit_iter(struct btree_trans *trans, struct btree *b)705{706	struct btree_path *path;707	unsigned i;708 709	trans_for_each_path_with_node(trans, b, path, i)710		__btree_path_level_init(path, b->c.level);711 712	bch2_trans_revalidate_updates_in_node(trans, b);713}714 715/* Btree path: traverse, set_pos: */716 717static inline int btree_path_lock_root(struct btree_trans *trans,718				       struct btree_path *path,719				       unsigned depth_want,720				       unsigned long trace_ip)721{722	struct bch_fs *c = trans->c;723	struct btree *b, **rootp = &bch2_btree_id_root(c, path->btree_id)->b;724	enum six_lock_type lock_type;725	unsigned i;726	int ret;727 728	EBUG_ON(path->nodes_locked);729 730	while (1) {731		b = READ_ONCE(*rootp);732		path->level = READ_ONCE(b->c.level);733 734		if (unlikely(path->level < depth_want)) {735			/*736			 * the root is at a lower depth than the depth we want:737			 * got to the end of the btree, or we're walking nodes738			 * greater than some depth and there are no nodes >=739			 * that depth740			 */741			path->level = depth_want;742			for (i = path->level; i < BTREE_MAX_DEPTH; i++)743				path->l[i].b = NULL;744			return 1;745		}746 747		lock_type = __btree_lock_want(path, path->level);748		ret = btree_node_lock(trans, path, &b->c,749				      path->level, lock_type, trace_ip);750		if (unlikely(ret)) {751			if (bch2_err_matches(ret, BCH_ERR_lock_fail_root_changed))752				continue;753			if (bch2_err_matches(ret, BCH_ERR_transaction_restart))754				return ret;755			BUG();756		}757 758		if (likely(b == READ_ONCE(*rootp) &&759			   b->c.level == path->level &&760			   !race_fault())) {761			for (i = 0; i < path->level; i++)762				path->l[i].b = ERR_PTR(-BCH_ERR_no_btree_node_lock_root);763			path->l[path->level].b = b;764			for (i = path->level + 1; i < BTREE_MAX_DEPTH; i++)765				path->l[i].b = NULL;766 767			mark_btree_node_locked(trans, path, path->level,768					       (enum btree_node_locked_type) lock_type);769			bch2_btree_path_level_init(trans, path, b);770			return 0;771		}772 773		six_unlock_type(&b->c.lock, lock_type);774	}775}776 777noinline778static int btree_path_prefetch(struct btree_trans *trans, struct btree_path *path)779{780	struct bch_fs *c = trans->c;781	struct btree_path_level *l = path_l(path);782	struct btree_node_iter node_iter = l->iter;783	struct bkey_packed *k;784	struct bkey_buf tmp;785	unsigned nr = test_bit(BCH_FS_started, &c->flags)786		? (path->level > 1 ? 0 :  2)787		: (path->level > 1 ? 1 : 16);788	bool was_locked = btree_node_locked(path, path->level);789	int ret = 0;790 791	bch2_bkey_buf_init(&tmp);792 793	while (nr-- && !ret) {794		if (!bch2_btree_node_relock(trans, path, path->level))795			break;796 797		bch2_btree_node_iter_advance(&node_iter, l->b);798		k = bch2_btree_node_iter_peek(&node_iter, l->b);799		if (!k)800			break;801 802		bch2_bkey_buf_unpack(&tmp, c, l->b, k);803		ret = bch2_btree_node_prefetch(trans, path, tmp.k, path->btree_id,804					       path->level - 1);805	}806 807	if (!was_locked)808		btree_node_unlock(trans, path, path->level);809 810	bch2_bkey_buf_exit(&tmp, c);811	return ret;812}813 814static int btree_path_prefetch_j(struct btree_trans *trans, struct btree_path *path,815				 struct btree_and_journal_iter *jiter)816{817	struct bch_fs *c = trans->c;818	struct bkey_s_c k;819	struct bkey_buf tmp;820	unsigned nr = test_bit(BCH_FS_started, &c->flags)821		? (path->level > 1 ? 0 :  2)822		: (path->level > 1 ? 1 : 16);823	bool was_locked = btree_node_locked(path, path->level);824	int ret = 0;825 826	bch2_bkey_buf_init(&tmp);827 828	while (nr-- && !ret) {829		if (!bch2_btree_node_relock(trans, path, path->level))830			break;831 832		bch2_btree_and_journal_iter_advance(jiter);833		k = bch2_btree_and_journal_iter_peek(jiter);834		if (!k.k)835			break;836 837		bch2_bkey_buf_reassemble(&tmp, c, k);838		ret = bch2_btree_node_prefetch(trans, path, tmp.k, path->btree_id,839					       path->level - 1);840	}841 842	if (!was_locked)843		btree_node_unlock(trans, path, path->level);844 845	bch2_bkey_buf_exit(&tmp, c);846	return ret;847}848 849static noinline void btree_node_mem_ptr_set(struct btree_trans *trans,850					    struct btree_path *path,851					    unsigned plevel, struct btree *b)852{853	struct btree_path_level *l = &path->l[plevel];854	bool locked = btree_node_locked(path, plevel);855	struct bkey_packed *k;856	struct bch_btree_ptr_v2 *bp;857 858	if (!bch2_btree_node_relock(trans, path, plevel))859		return;860 861	k = bch2_btree_node_iter_peek_all(&l->iter, l->b);862	BUG_ON(k->type != KEY_TYPE_btree_ptr_v2);863 864	bp = (void *) bkeyp_val(&l->b->format, k);865	bp->mem_ptr = (unsigned long)b;866 867	if (!locked)868		btree_node_unlock(trans, path, plevel);869}870 871static noinline int btree_node_iter_and_journal_peek(struct btree_trans *trans,872						     struct btree_path *path,873						     unsigned flags,874						     struct bkey_buf *out)875{876	struct bch_fs *c = trans->c;877	struct btree_path_level *l = path_l(path);878	struct btree_and_journal_iter jiter;879	struct bkey_s_c k;880	int ret = 0;881 882	__bch2_btree_and_journal_iter_init_node_iter(trans, &jiter, l->b, l->iter, path->pos);883 884	k = bch2_btree_and_journal_iter_peek(&jiter);885	if (!k.k) {886		struct printbuf buf = PRINTBUF;887 888		prt_str(&buf, "node not found at pos ");889		bch2_bpos_to_text(&buf, path->pos);890		prt_str(&buf, " at btree ");891		bch2_btree_pos_to_text(&buf, c, l->b);892 893		ret = bch2_fs_topology_error(c, "%s", buf.buf);894		printbuf_exit(&buf);895		goto err;896	}897 898	bch2_bkey_buf_reassemble(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);903 904err:905	bch2_btree_and_journal_iter_exit(&jiter);906	return ret;907}908 909static __always_inline int btree_path_down(struct btree_trans *trans,910					   struct btree_path *path,911					   unsigned flags,912					   unsigned long trace_ip)913{914	struct bch_fs *c = trans->c;915	struct btree_path_level *l = path_l(path);916	struct btree *b;917	unsigned level = path->level - 1;918	enum six_lock_type lock_type = __btree_lock_want(path, level);919	struct bkey_buf tmp;920	int ret;921 922	EBUG_ON(!btree_node_locked(path, path->level));923 924	bch2_bkey_buf_init(&tmp);925 926	if (unlikely(trans->journal_replay_not_finished)) {927		ret = btree_node_iter_and_journal_peek(trans, path, flags, &tmp);928		if (ret)929			goto err;930	} else {931		struct bkey_packed *k = bch2_btree_node_iter_peek(&l->iter, l->b);932		if (!k) {933			struct printbuf buf = PRINTBUF;934 935			prt_str(&buf, "node not found at pos ");936			bch2_bpos_to_text(&buf, path->pos);937			prt_str(&buf, " within parent node ");938			bch2_bkey_val_to_text(&buf, c, bkey_i_to_s_c(&l->b->key));939 940			bch2_fs_fatal_error(c, "%s", buf.buf);941			printbuf_exit(&buf);942			ret = -BCH_ERR_btree_need_topology_repair;943			goto err;944		}945 946		bch2_bkey_buf_unpack(&tmp, c, l->b, k);947 948		if ((flags & BTREE_ITER_prefetch) &&949		    c->opts.btree_node_prefetch) {950			ret = btree_path_prefetch(trans, path);951			if (ret)952				goto err;953		}954	}955 956	b = bch2_btree_node_get(trans, path, tmp.k, level, lock_type, trace_ip);957	ret = PTR_ERR_OR_ZERO(b);958	if (unlikely(ret))959		goto err;960 961	if (likely(!trans->journal_replay_not_finished &&962		   tmp.k->k.type == KEY_TYPE_btree_ptr_v2) &&963	    unlikely(b != btree_node_mem_ptr(tmp.k)))964		btree_node_mem_ptr_set(trans, path, level + 1, b);965 966	if (btree_node_read_locked(path, level + 1))967		btree_node_unlock(trans, path, level + 1);968 969	mark_btree_node_locked(trans, path, level,970			       (enum btree_node_locked_type) lock_type);971	path->level = level;972	bch2_btree_path_level_init(trans, path, b);973 974	bch2_btree_path_verify_locks(path);975err:976	bch2_bkey_buf_exit(&tmp, c);977	return ret;978}979 980static int bch2_btree_path_traverse_all(struct btree_trans *trans)981{982	struct bch_fs *c = trans->c;983	struct btree_path *path;984	unsigned long trace_ip = _RET_IP_;985	unsigned i;986	int ret = 0;987 988	if (trans->in_traverse_all)989		return -BCH_ERR_transaction_restart_in_traverse_all;990 991	trans->in_traverse_all = true;992retry_all:993	trans->restarted = 0;994	trans->last_restarted_ip = 0;995 996	trans_for_each_path(trans, path, i)997		path->should_be_locked = false;998 999	btree_trans_sort_paths(trans);1000 1001	bch2_trans_unlock(trans);1002	cond_resched();1003	trans_set_locked(trans);1004 1005	if (unlikely(trans->memory_allocation_failure)) {1006		struct closure cl;1007 1008		closure_init_stack(&cl);1009 1010		do {1011			ret = bch2_btree_cache_cannibalize_lock(trans, &cl);1012			closure_sync(&cl);1013		} while (ret);1014	}1015 1016	/* Now, redo traversals in correct order: */1017	i = 0;1018	while (i < trans->nr_sorted) {1019		btree_path_idx_t idx = trans->sorted[i];1020 1021		/*1022		 * Traversing a path can cause another path to be added at about1023		 * the same position:1024		 */1025		if (trans->paths[idx].uptodate) {1026			__btree_path_get(trans, &trans->paths[idx], false);1027			ret = bch2_btree_path_traverse_one(trans, idx, 0, _THIS_IP_);1028			__btree_path_put(trans, &trans->paths[idx], false);1029 1030			if (bch2_err_matches(ret, BCH_ERR_transaction_restart) ||1031			    bch2_err_matches(ret, ENOMEM))1032				goto retry_all;1033			if (ret)1034				goto err;1035		} else {1036			i++;1037		}1038	}1039 1040	/*1041	 * We used to assert that all paths had been traversed here1042	 * (path->uptodate < BTREE_ITER_NEED_TRAVERSE); however, since1043	 * path->should_be_locked is not set yet, we might have unlocked and1044	 * then failed to relock a path - that's fine.1045	 */1046err:1047	bch2_btree_cache_cannibalize_unlock(trans);1048 1049	trans->in_traverse_all = false;1050 1051	trace_and_count(c, trans_traverse_all, trans, trace_ip);1052	return ret;1053}1054 1055static inline bool btree_path_check_pos_in_node(struct btree_path *path,1056						unsigned l, int check_pos)1057{1058	if (check_pos < 0 && btree_path_pos_before_node(path, path->l[l].b))1059		return false;1060	if (check_pos > 0 && btree_path_pos_after_node(path, path->l[l].b))1061		return false;1062	return true;1063}1064 1065static inline bool btree_path_good_node(struct btree_trans *trans,1066					struct btree_path *path,1067					unsigned l, int check_pos)1068{1069	return is_btree_node(path, l) &&1070		bch2_btree_node_relock(trans, path, l) &&1071		btree_path_check_pos_in_node(path, l, check_pos);1072}1073 1074static void btree_path_set_level_down(struct btree_trans *trans,1075				      struct btree_path *path,1076				      unsigned new_level)1077{1078	unsigned l;1079 1080	path->level = new_level;1081 1082	for (l = path->level + 1; l < BTREE_MAX_DEPTH; l++)1083		if (btree_lock_want(path, l) == BTREE_NODE_UNLOCKED)1084			btree_node_unlock(trans, path, l);1085 1086	btree_path_set_dirty(path, BTREE_ITER_NEED_TRAVERSE);1087	bch2_btree_path_verify(trans, path);1088}1089 1090static noinline unsigned __btree_path_up_until_good_node(struct btree_trans *trans,1091							 struct btree_path *path,1092							 int check_pos)1093{1094	unsigned i, l = path->level;1095again:1096	while (btree_path_node(path, l) &&1097	       !btree_path_good_node(trans, path, l, check_pos))1098		__btree_path_set_level_up(trans, path, l++);1099 1100	/* If we need intent locks, take them too: */1101	for (i = l + 1;1102	     i < path->locks_want && btree_path_node(path, i);1103	     i++)1104		if (!bch2_btree_node_relock(trans, path, i)) {1105			while (l <= i)1106				__btree_path_set_level_up(trans, path, l++);1107			goto again;1108		}1109 1110	return l;1111}1112 1113static inline unsigned btree_path_up_until_good_node(struct btree_trans *trans,1114						     struct btree_path *path,1115						     int check_pos)1116{1117	return likely(btree_node_locked(path, path->level) &&1118		      btree_path_check_pos_in_node(path, path->level, check_pos))1119		? path->level1120		: __btree_path_up_until_good_node(trans, path, check_pos);1121}1122 1123/*1124 * This is the main state machine for walking down the btree - walks down to a1125 * specified depth1126 *1127 * Returns 0 on success, -EIO on error (error reading in a btree node).1128 *1129 * On error, caller (peek_node()/peek_key()) must return NULL; the error is1130 * stashed in the iterator and returned from bch2_trans_exit().1131 */1132int bch2_btree_path_traverse_one(struct btree_trans *trans,1133				 btree_path_idx_t path_idx,1134				 unsigned flags,1135				 unsigned long trace_ip)1136{1137	struct btree_path *path = &trans->paths[path_idx];1138	unsigned depth_want = path->level;1139	int ret = -((int) trans->restarted);1140 1141	if (unlikely(ret))1142		goto out;1143 1144	if (unlikely(!trans->srcu_held))1145		bch2_trans_srcu_lock(trans);1146 1147	trace_btree_path_traverse_start(trans, path);1148 1149	/*1150	 * Ensure we obey path->should_be_locked: if it's set, we can't unlock1151	 * and re-traverse the path without a transaction restart:1152	 */1153	if (path->should_be_locked) {1154		ret = bch2_btree_path_relock(trans, path, trace_ip);1155		goto out;1156	}1157 1158	if (path->cached) {1159		ret = bch2_btree_path_traverse_cached(trans, path, flags);1160		goto out;1161	}1162 1163	path = &trans->paths[path_idx];1164 1165	if (unlikely(path->level >= BTREE_MAX_DEPTH))1166		goto out_uptodate;1167 1168	path->level = btree_path_up_until_good_node(trans, path, 0);1169	unsigned max_level = path->level;1170 1171	EBUG_ON(btree_path_node(path, path->level) &&1172		!btree_node_locked(path, path->level));1173 1174	/*1175	 * Note: path->nodes[path->level] may be temporarily NULL here - that1176	 * would indicate to other code that we got to the end of the btree,1177	 * here it indicates that relocking the root failed - it's critical that1178	 * btree_path_lock_root() comes next and that it can't fail1179	 */1180	while (path->level > depth_want) {1181		ret = btree_path_node(path, path->level)1182			? btree_path_down(trans, path, flags, trace_ip)1183			: btree_path_lock_root(trans, path, depth_want, trace_ip);1184		if (unlikely(ret)) {1185			if (ret == 1) {1186				/*1187				 * No nodes at this level - got to the end of1188				 * the btree:1189				 */1190				ret = 0;1191				goto out;1192			}1193 1194			__bch2_btree_path_unlock(trans, path);1195			path->level = depth_want;1196			path->l[path->level].b = ERR_PTR(ret);1197			goto out;1198		}1199	}1200 1201	if (unlikely(max_level > path->level)) {1202		struct btree_path *linked;1203		unsigned iter;1204 1205		trans_for_each_path_with_node(trans, path_l(path)->b, linked, iter)1206			for (unsigned j = path->level + 1; j < max_level; j++)1207				linked->l[j] = path->l[j];1208	}1209 1210out_uptodate:1211	path->uptodate = BTREE_ITER_UPTODATE;1212	trace_btree_path_traverse_end(trans, path);1213out:1214	if (bch2_err_matches(ret, BCH_ERR_transaction_restart) != !!trans->restarted)1215		panic("ret %s (%i) trans->restarted %s (%i)\n",1216		      bch2_err_str(ret), ret,1217		      bch2_err_str(trans->restarted), trans->restarted);1218	bch2_btree_path_verify(trans, path);1219	return ret;1220}1221 1222static inline void btree_path_copy(struct btree_trans *trans, struct btree_path *dst,1223			    struct btree_path *src)1224{1225	unsigned i, offset = offsetof(struct btree_path, pos);1226 1227	memcpy((void *) dst + offset,1228	       (void *) src + offset,1229	       sizeof(struct btree_path) - offset);1230 1231	for (i = 0; i < BTREE_MAX_DEPTH; i++) {1232		unsigned t = btree_node_locked_type(dst, i);1233 1234		if (t != BTREE_NODE_UNLOCKED)1235			six_lock_increment(&dst->l[i].b->c.lock, t);1236	}1237}1238 1239static btree_path_idx_t btree_path_clone(struct btree_trans *trans, btree_path_idx_t src,1240					 bool intent, unsigned long ip)1241{1242	btree_path_idx_t new = btree_path_alloc(trans, src);1243	btree_path_copy(trans, trans->paths + new, trans->paths + src);1244	__btree_path_get(trans, trans->paths + new, intent);1245#ifdef TRACK_PATH_ALLOCATED1246	trans->paths[new].ip_allocated = ip;1247#endif1248	return new;1249}1250 1251__flatten1252btree_path_idx_t __bch2_btree_path_make_mut(struct btree_trans *trans,1253			btree_path_idx_t path, bool intent, unsigned long ip)1254{1255	struct btree_path *old = trans->paths + path;1256	__btree_path_put(trans, trans->paths + path, intent);1257	path = btree_path_clone(trans, path, intent, ip);1258	trace_btree_path_clone(trans, old, trans->paths + path);1259	trans->paths[path].preserve = false;1260	return path;1261}1262 1263btree_path_idx_t __must_check1264__bch2_btree_path_set_pos(struct btree_trans *trans,1265			  btree_path_idx_t path_idx, struct bpos new_pos,1266			  bool intent, unsigned long ip)1267{1268	int cmp = bpos_cmp(new_pos, trans->paths[path_idx].pos);1269 1270	bch2_trans_verify_not_in_restart(trans);1271	EBUG_ON(!trans->paths[path_idx].ref);1272 1273	trace_btree_path_set_pos(trans, trans->paths + path_idx, &new_pos);1274 1275	path_idx = bch2_btree_path_make_mut(trans, path_idx, intent, ip);1276 1277	struct btree_path *path = trans->paths + path_idx;1278	path->pos		= new_pos;1279	trans->paths_sorted	= false;1280 1281	if (unlikely(path->cached)) {1282		btree_node_unlock(trans, path, 0);1283		path->l[0].b = ERR_PTR(-BCH_ERR_no_btree_node_up);1284		btree_path_set_dirty(path, BTREE_ITER_NEED_TRAVERSE);1285		goto out;1286	}1287 1288	unsigned level = btree_path_up_until_good_node(trans, path, cmp);1289 1290	if (btree_path_node(path, level)) {1291		struct btree_path_level *l = &path->l[level];1292 1293		BUG_ON(!btree_node_locked(path, level));1294		/*1295		 * We might have to skip over many keys, or just a few: try1296		 * advancing the node iterator, and if we have to skip over too1297		 * many keys just reinit it (or if we're rewinding, since that1298		 * is expensive).1299		 */1300		if (cmp < 0 ||1301		    !btree_path_advance_to_pos(path, l, 8))1302			bch2_btree_node_iter_init(&l->iter, l->b, &path->pos);1303 1304		/*1305		 * Iterators to interior nodes should always be pointed at the first non1306		 * whiteout:1307		 */1308		if (unlikely(level))1309			bch2_btree_node_iter_peek(&l->iter, l->b);1310	}1311 1312	if (unlikely(level != path->level)) {1313		btree_path_set_dirty(path, BTREE_ITER_NEED_TRAVERSE);1314		__bch2_btree_path_unlock(trans, path);1315	}1316out:1317	bch2_btree_path_verify(trans, path);1318	return path_idx;1319}1320 1321/* Btree path: main interface: */1322 1323static struct btree_path *have_path_at_pos(struct btree_trans *trans, struct btree_path *path)1324{1325	struct btree_path *sib;1326 1327	sib = prev_btree_path(trans, path);1328	if (sib && !btree_path_cmp(sib, path))1329		return sib;1330 1331	sib = next_btree_path(trans, path);1332	if (sib && !btree_path_cmp(sib, path))1333		return sib;1334 1335	return NULL;1336}1337 1338static struct btree_path *have_node_at_pos(struct btree_trans *trans, struct btree_path *path)1339{1340	struct btree_path *sib;1341 1342	sib = prev_btree_path(trans, path);1343	if (sib && sib->level == path->level && path_l(sib)->b == path_l(path)->b)1344		return sib;1345 1346	sib = next_btree_path(trans, path);1347	if (sib && sib->level == path->level && path_l(sib)->b == path_l(path)->b)1348		return sib;1349 1350	return NULL;1351}1352 1353static inline void __bch2_path_free(struct btree_trans *trans, btree_path_idx_t path)1354{1355	__bch2_btree_path_unlock(trans, trans->paths + path);1356	btree_path_list_remove(trans, trans->paths + path);1357	__clear_bit(path, trans->paths_allocated);1358}1359 1360static bool bch2_btree_path_can_relock(struct btree_trans *trans, struct btree_path *path)1361{1362	unsigned l = path->level;1363 1364	do {1365		if (!btree_path_node(path, l))1366			break;1367 1368		if (!is_btree_node(path, l))1369			return false;1370 1371		if (path->l[l].lock_seq != path->l[l].b->c.lock.seq)1372			return false;1373 1374		l++;1375	} while (l < path->locks_want);1376 1377	return true;1378}1379 1380void bch2_path_put(struct btree_trans *trans, btree_path_idx_t path_idx, bool intent)1381{1382	struct btree_path *path = trans->paths + path_idx, *dup;1383 1384	if (!__btree_path_put(trans, path, intent))1385		return;1386 1387	dup = path->preserve1388		? have_path_at_pos(trans, path)1389		: have_node_at_pos(trans, path);1390 1391	trace_btree_path_free(trans, path_idx, dup);1392 1393	if (!dup && !(!path->preserve && !is_btree_node(path, path->level)))1394		return;1395 1396	if (path->should_be_locked && !trans->restarted) {1397		if (!dup)1398			return;1399 1400		if (!(trans->locked1401		      ? bch2_btree_path_relock_norestart(trans, dup)1402		      : bch2_btree_path_can_relock(trans, dup)))1403			return;1404	}1405 1406	if (dup) {1407		dup->preserve		|= path->preserve;1408		dup->should_be_locked	|= path->should_be_locked;1409	}1410 1411	__bch2_path_free(trans, path_idx);1412}1413 1414static void bch2_path_put_nokeep(struct btree_trans *trans, btree_path_idx_t path,1415				 bool intent)1416{1417	if (!__btree_path_put(trans, trans->paths + path, intent))1418		return;1419 1420	__bch2_path_free(trans, path);1421}1422 1423void __noreturn bch2_trans_restart_error(struct btree_trans *trans, u32 restart_count)1424{1425	panic("trans->restart_count %u, should be %u, last restarted by %pS\n",1426	      trans->restart_count, restart_count,1427	      (void *) trans->last_begin_ip);1428}1429 1430void __noreturn bch2_trans_in_restart_error(struct btree_trans *trans)1431{1432	panic("in transaction restart: %s, last restarted by %pS\n",1433	      bch2_err_str(trans->restarted),1434	      (void *) trans->last_restarted_ip);1435}1436 1437void __noreturn bch2_trans_unlocked_error(struct btree_trans *trans)1438{1439	panic("trans should be locked, unlocked by %pS\n",1440	      (void *) trans->last_unlock_ip);1441}1442 1443noinline __cold1444void bch2_trans_updates_to_text(struct printbuf *buf, struct btree_trans *trans)1445{1446	prt_printf(buf, "%u transaction updates for %s journal seq %llu\n",1447		   trans->nr_updates, trans->fn, trans->journal_res.seq);1448	printbuf_indent_add(buf, 2);1449 1450	trans_for_each_update(trans, i) {1451		struct bkey_s_c old = { &i->old_k, i->old_v };1452 1453		prt_printf(buf, "update: btree=%s cached=%u %pS\n",1454		       bch2_btree_id_str(i->btree_id),1455		       i->cached,1456		       (void *) i->ip_allocated);1457 1458		prt_printf(buf, "  old ");1459		bch2_bkey_val_to_text(buf, trans->c, old);1460		prt_newline(buf);1461 1462		prt_printf(buf, "  new ");1463		bch2_bkey_val_to_text(buf, trans->c, bkey_i_to_s_c(i->k));1464		prt_newline(buf);1465	}1466 1467	for (struct jset_entry *e = trans->journal_entries;1468	     e != btree_trans_journal_entries_top(trans);1469	     e = vstruct_next(e))1470		bch2_journal_entry_to_text(buf, trans->c, e);1471 1472	printbuf_indent_sub(buf, 2);1473}1474 1475noinline __cold1476void bch2_dump_trans_updates(struct btree_trans *trans)1477{1478	struct printbuf buf = PRINTBUF;1479 1480	bch2_trans_updates_to_text(&buf, trans);1481	bch2_print_str(trans->c, buf.buf);1482	printbuf_exit(&buf);1483}1484 1485static void bch2_btree_path_to_text_short(struct printbuf *out, struct btree_trans *trans, btree_path_idx_t path_idx)1486{1487	struct btree_path *path = trans->paths + path_idx;1488 1489	prt_printf(out, "path: idx %3u ref %u:%u %c %c %c btree=%s l=%u pos ",1490		   path_idx, path->ref, path->intent_ref,1491		   path->preserve ? 'P' : ' ',1492		   path->should_be_locked ? 'S' : ' ',1493		   path->cached ? 'C' : 'B',1494		   bch2_btree_id_str(path->btree_id),1495		   path->level);1496	bch2_bpos_to_text(out, path->pos);1497 1498	if (!path->cached && btree_node_locked(path, path->level)) {1499		prt_char(out, ' ');1500		struct btree *b = path_l(path)->b;1501		bch2_bpos_to_text(out, b->data->min_key);1502		prt_char(out, '-');1503		bch2_bpos_to_text(out, b->key.k.p);1504	}1505 1506#ifdef TRACK_PATH_ALLOCATED1507	prt_printf(out, " %pS", (void *) path->ip_allocated);1508#endif1509}1510 1511static const char *btree_node_locked_str(enum btree_node_locked_type t)1512{1513	switch (t) {1514	case BTREE_NODE_UNLOCKED:1515		return "unlocked";1516	case BTREE_NODE_READ_LOCKED:1517		return "read";1518	case BTREE_NODE_INTENT_LOCKED:1519		return "intent";1520	case BTREE_NODE_WRITE_LOCKED:1521		return "write";1522	default:1523		return NULL;1524	}1525}1526 1527void bch2_btree_path_to_text(struct printbuf *out, struct btree_trans *trans, btree_path_idx_t path_idx)1528{1529	bch2_btree_path_to_text_short(out, trans, path_idx);1530 1531	struct btree_path *path = trans->paths + path_idx;1532 1533	prt_printf(out, " uptodate %u locks_want %u", path->uptodate, path->locks_want);1534	prt_newline(out);1535 1536	printbuf_indent_add(out, 2);1537	for (unsigned l = 0; l < BTREE_MAX_DEPTH; l++) {1538		prt_printf(out, "l=%u locks %s seq %u node ", l,1539			   btree_node_locked_str(btree_node_locked_type(path, l)),1540			   path->l[l].lock_seq);1541 1542		int ret = PTR_ERR_OR_ZERO(path->l[l].b);1543		if (ret)1544			prt_str(out, bch2_err_str(ret));1545		else1546			prt_printf(out, "%px", path->l[l].b);1547		prt_newline(out);1548	}1549	printbuf_indent_sub(out, 2);1550}1551 1552static noinline __cold1553void __bch2_trans_paths_to_text(struct printbuf *out, struct btree_trans *trans,1554				bool nosort)1555{1556	struct trans_for_each_path_inorder_iter iter;1557 1558	if (!nosort)1559		btree_trans_sort_paths(trans);1560 1561	trans_for_each_path_idx_inorder(trans, iter) {1562		bch2_btree_path_to_text_short(out, trans, iter.path_idx);1563		prt_newline(out);1564	}1565}1566 1567noinline __cold1568void bch2_trans_paths_to_text(struct printbuf *out, struct btree_trans *trans)1569{1570	__bch2_trans_paths_to_text(out, trans, false);1571}1572 1573static noinline __cold1574void __bch2_dump_trans_paths_updates(struct btree_trans *trans, bool nosort)1575{1576	struct printbuf buf = PRINTBUF;1577 1578	__bch2_trans_paths_to_text(&buf, trans, nosort);1579	bch2_trans_updates_to_text(&buf, trans);1580 1581	bch2_print_str(trans->c, buf.buf);1582	printbuf_exit(&buf);1583}1584 1585noinline __cold1586void bch2_dump_trans_paths_updates(struct btree_trans *trans)1587{1588	__bch2_dump_trans_paths_updates(trans, false);1589}1590 1591noinline __cold1592static void bch2_trans_update_max_paths(struct btree_trans *trans)1593{1594	struct btree_transaction_stats *s = btree_trans_stats(trans);1595	struct printbuf buf = PRINTBUF;1596	size_t nr = bitmap_weight(trans->paths_allocated, trans->nr_paths);1597 1598	bch2_trans_paths_to_text(&buf, trans);1599 1600	if (!buf.allocation_failure) {1601		mutex_lock(&s->lock);1602		if (nr > s->nr_max_paths) {1603			s->nr_max_paths = nr;1604			swap(s->max_paths_text, buf.buf);1605		}1606		mutex_unlock(&s->lock);1607	}1608 1609	printbuf_exit(&buf);1610 1611	trans->nr_paths_max = nr;1612}1613 1614noinline __cold1615int __bch2_btree_trans_too_many_iters(struct btree_trans *trans)1616{1617	if (trace_trans_restart_too_many_iters_enabled()) {1618		struct printbuf buf = PRINTBUF;1619 1620		bch2_trans_paths_to_text(&buf, trans);1621		trace_trans_restart_too_many_iters(trans, _THIS_IP_, buf.buf);1622		printbuf_exit(&buf);1623	}1624 1625	count_event(trans->c, trans_restart_too_many_iters);1626 1627	return btree_trans_restart(trans, BCH_ERR_transaction_restart_too_many_iters);1628}1629 1630static noinline void btree_path_overflow(struct btree_trans *trans)1631{1632	bch2_dump_trans_paths_updates(trans);1633	bch_err(trans->c, "trans path overflow");1634}1635 1636static noinline void btree_paths_realloc(struct btree_trans *trans)1637{1638	unsigned nr = trans->nr_paths * 2;1639 1640	void *p = kvzalloc(BITS_TO_LONGS(nr) * sizeof(unsigned long) +1641			  sizeof(struct btree_trans_paths) +1642			  nr * sizeof(struct btree_path) +1643			  nr * sizeof(btree_path_idx_t) + 8 +1644			  nr * sizeof(struct btree_insert_entry), GFP_KERNEL|__GFP_NOFAIL);1645 1646	unsigned long *paths_allocated = p;1647	memcpy(paths_allocated, trans->paths_allocated, BITS_TO_LONGS(trans->nr_paths) * sizeof(unsigned long));1648	p += BITS_TO_LONGS(nr) * sizeof(unsigned long);1649 1650	p += sizeof(struct btree_trans_paths);1651	struct btree_path *paths = p;1652	*trans_paths_nr(paths) = nr;1653	memcpy(paths, trans->paths, trans->nr_paths * sizeof(struct btree_path));1654	p += nr * sizeof(struct btree_path);1655 1656	btree_path_idx_t *sorted = p;1657	memcpy(sorted, trans->sorted, trans->nr_sorted * sizeof(btree_path_idx_t));1658	p += nr * sizeof(btree_path_idx_t) + 8;1659 1660	struct btree_insert_entry *updates = p;1661	memcpy(updates, trans->updates, trans->nr_paths * sizeof(struct btree_insert_entry));1662 1663	unsigned long *old = trans->paths_allocated;1664 1665	rcu_assign_pointer(trans->paths_allocated,	paths_allocated);1666	rcu_assign_pointer(trans->paths,		paths);1667	rcu_assign_pointer(trans->sorted,		sorted);1668	rcu_assign_pointer(trans->updates,		updates);1669 1670	trans->nr_paths		= nr;1671 1672	if (old != trans->_paths_allocated)1673		kfree_rcu_mightsleep(old);1674}1675 1676static inline btree_path_idx_t btree_path_alloc(struct btree_trans *trans,1677						btree_path_idx_t pos)1678{1679	btree_path_idx_t idx = find_first_zero_bit(trans->paths_allocated, trans->nr_paths);1680 1681	if (unlikely(idx == trans->nr_paths)) {1682		if (trans->nr_paths == BTREE_ITER_MAX) {1683			btree_path_overflow(trans);1684			return 0;1685		}1686 1687		btree_paths_realloc(trans);1688	}1689 1690	/*1691	 * Do this before marking the new path as allocated, since it won't be1692	 * initialized yet:1693	 */1694	if (unlikely(idx > trans->nr_paths_max))1695		bch2_trans_update_max_paths(trans);1696 1697	__set_bit(idx, trans->paths_allocated);1698 1699	struct btree_path *path = &trans->paths[idx];1700	path->ref		= 0;1701	path->intent_ref	= 0;1702	path->nodes_locked	= 0;1703 1704	btree_path_list_add(trans, pos, idx);1705	trans->paths_sorted = false;1706	return idx;1707}1708 1709btree_path_idx_t bch2_path_get(struct btree_trans *trans,1710			     enum btree_id btree_id, struct bpos pos,1711			     unsigned locks_want, unsigned level,1712			     unsigned flags, unsigned long ip)1713{1714	struct btree_path *path;1715	bool cached = flags & BTREE_ITER_cached;1716	bool intent = flags & BTREE_ITER_intent;1717	struct trans_for_each_path_inorder_iter iter;1718	btree_path_idx_t path_pos = 0, path_idx;1719 1720	bch2_trans_verify_not_unlocked(trans);1721	bch2_trans_verify_not_in_restart(trans);1722	bch2_trans_verify_locks(trans);1723 1724	btree_trans_sort_paths(trans);1725 1726	trans_for_each_path_inorder(trans, path, iter) {1727		if (__btree_path_cmp(path,1728				     btree_id,1729				     cached,1730				     pos,1731				     level) > 0)1732			break;1733 1734		path_pos = iter.path_idx;1735	}1736 1737	if (path_pos &&1738	    trans->paths[path_pos].cached	== cached &&1739	    trans->paths[path_pos].btree_id	== btree_id &&1740	    trans->paths[path_pos].level	== level) {1741		trace_btree_path_get(trans, trans->paths + path_pos, &pos);1742 1743		__btree_path_get(trans, trans->paths + path_pos, intent);1744		path_idx = bch2_btree_path_set_pos(trans, path_pos, pos, intent, ip);1745		path = trans->paths + path_idx;1746	} else {1747		path_idx = btree_path_alloc(trans, path_pos);1748		path = trans->paths + path_idx;1749 1750		__btree_path_get(trans, path, intent);1751		path->pos			= pos;1752		path->btree_id			= btree_id;1753		path->cached			= cached;1754		path->uptodate			= BTREE_ITER_NEED_TRAVERSE;1755		path->should_be_locked		= false;1756		path->level			= level;1757		path->locks_want		= locks_want;1758		path->nodes_locked		= 0;1759		for (unsigned i = 0; i < ARRAY_SIZE(path->l); i++)1760			path->l[i].b		= ERR_PTR(-BCH_ERR_no_btree_node_init);1761#ifdef TRACK_PATH_ALLOCATED1762		path->ip_allocated		= ip;1763#endif1764		trans->paths_sorted		= false;1765 1766		trace_btree_path_alloc(trans, path);1767	}1768 1769	if (!(flags & BTREE_ITER_nopreserve))1770		path->preserve = true;1771 1772	if (path->intent_ref)1773		locks_want = max(locks_want, level + 1);1774 1775	/*1776	 * If the path has locks_want greater than requested, we don't downgrade1777	 * it here - on transaction restart because btree node split needs to1778	 * upgrade locks, we might be putting/getting the iterator again.1779	 * Downgrading iterators only happens via bch2_trans_downgrade(), after1780	 * a successful transaction commit.1781	 */1782 1783	locks_want = min(locks_want, BTREE_MAX_DEPTH);1784	if (locks_want > path->locks_want)1785		bch2_btree_path_upgrade_noupgrade_sibs(trans, path, locks_want, NULL);1786 1787	return path_idx;1788}1789 1790btree_path_idx_t bch2_path_get_unlocked_mut(struct btree_trans *trans,1791					    enum btree_id btree_id,1792					    unsigned level,1793					    struct bpos pos)1794{1795	btree_path_idx_t path_idx = bch2_path_get(trans, btree_id, pos, level + 1, level,1796			     BTREE_ITER_nopreserve|1797			     BTREE_ITER_intent, _RET_IP_);1798	path_idx = bch2_btree_path_make_mut(trans, path_idx, true, _RET_IP_);1799 1800	struct btree_path *path = trans->paths + path_idx;1801	bch2_btree_path_downgrade(trans, path);1802	__bch2_btree_path_unlock(trans, path);1803	return path_idx;1804}1805 1806struct bkey_s_c bch2_btree_path_peek_slot(struct btree_path *path, struct bkey *u)1807{1808 1809	struct btree_path_level *l = path_l(path);1810	struct bkey_packed *_k;1811	struct bkey_s_c k;1812 1813	if (unlikely(!l->b))1814		return bkey_s_c_null;1815 1816	EBUG_ON(path->uptodate != BTREE_ITER_UPTODATE);1817	EBUG_ON(!btree_node_locked(path, path->level));1818 1819	if (!path->cached) {1820		_k = bch2_btree_node_iter_peek_all(&l->iter, l->b);1821		k = _k ? bkey_disassemble(l->b, _k, u) : bkey_s_c_null;1822 1823		EBUG_ON(k.k && bkey_deleted(k.k) && bpos_eq(k.k->p, path->pos));1824 1825		if (!k.k || !bpos_eq(path->pos, k.k->p))1826			goto hole;1827	} else {1828		struct bkey_cached *ck = (void *) path->l[0].b;1829		if (!ck)1830			return bkey_s_c_null;1831 1832		EBUG_ON(path->btree_id != ck->key.btree_id ||1833			!bkey_eq(path->pos, ck->key.pos));1834 1835		*u = ck->k->k;1836		k = bkey_i_to_s_c(ck->k);1837	}1838 1839	return k;1840hole:1841	bkey_init(u);1842	u->p = path->pos;1843	return (struct bkey_s_c) { u, NULL };1844}1845 1846 1847void bch2_set_btree_iter_dontneed(struct btree_iter *iter)1848{1849	struct btree_trans *trans = iter->trans;1850 1851	if (!iter->path || trans->restarted)1852		return;1853 1854	struct btree_path *path = btree_iter_path(trans, iter);1855	path->preserve		= false;1856	if (path->ref == 1)1857		path->should_be_locked	= false;1858}1859/* Btree iterators: */1860 1861int __must_check1862__bch2_btree_iter_traverse(struct btree_iter *iter)1863{1864	return bch2_btree_path_traverse(iter->trans, iter->path, iter->flags);1865}1866 1867int __must_check1868bch2_btree_iter_traverse(struct btree_iter *iter)1869{1870	struct btree_trans *trans = iter->trans;1871	int ret;1872 1873	bch2_trans_verify_not_unlocked(trans);1874 1875	iter->path = bch2_btree_path_set_pos(trans, iter->path,1876					btree_iter_search_key(iter),1877					iter->flags & BTREE_ITER_intent,1878					btree_iter_ip_allocated(iter));1879 1880	ret = bch2_btree_path_traverse(iter->trans, iter->path, iter->flags);1881	if (ret)1882		return ret;1883 1884	struct btree_path *path = btree_iter_path(trans, iter);1885	if (btree_path_node(path, path->level))1886		btree_path_set_should_be_locked(trans, path);1887	return 0;1888}1889 1890/* Iterate across nodes (leaf and interior nodes) */1891 1892struct btree *bch2_btree_iter_peek_node(struct btree_iter *iter)1893{1894	struct btree_trans *trans = iter->trans;1895	struct btree *b = NULL;1896	int ret;1897 1898	EBUG_ON(trans->paths[iter->path].cached);1899	bch2_btree_iter_verify(iter);1900 1901	ret = bch2_btree_path_traverse(trans, iter->path, iter->flags);1902	if (ret)1903		goto err;1904 1905	struct btree_path *path = btree_iter_path(trans, iter);1906	b = btree_path_node(path, path->level);1907	if (!b)1908		goto out;1909 1910	BUG_ON(bpos_lt(b->key.k.p, iter->pos));1911 1912	bkey_init(&iter->k);1913	iter->k.p = iter->pos = b->key.k.p;1914 1915	iter->path = bch2_btree_path_set_pos(trans, iter->path, b->key.k.p,1916					iter->flags & BTREE_ITER_intent,1917					btree_iter_ip_allocated(iter));1918	btree_path_set_should_be_locked(trans, btree_iter_path(trans, iter));1919out:1920	bch2_btree_iter_verify_entry_exit(iter);1921	bch2_btree_iter_verify(iter);1922 1923	return b;1924err:1925	b = ERR_PTR(ret);1926	goto out;1927}1928 1929/* Only kept for -tools */1930struct btree *bch2_btree_iter_peek_node_and_restart(struct btree_iter *iter)1931{1932	struct btree *b;1933 1934	while (b = bch2_btree_iter_peek_node(iter),1935	       bch2_err_matches(PTR_ERR_OR_ZERO(b), BCH_ERR_transaction_restart))1936		bch2_trans_begin(iter->trans);1937 1938	return b;1939}1940 1941struct btree *bch2_btree_iter_next_node(struct btree_iter *iter)1942{1943	struct btree_trans *trans = iter->trans;1944	struct btree *b = NULL;1945	int ret;1946 1947	EBUG_ON(trans->paths[iter->path].cached);1948	bch2_trans_verify_not_in_restart(trans);1949	bch2_btree_iter_verify(iter);1950 1951	ret = bch2_btree_path_traverse(trans, iter->path, iter->flags);1952	if (ret)1953		goto err;1954 1955 1956	struct btree_path *path = btree_iter_path(trans, iter);1957 1958	/* already at end? */1959	if (!btree_path_node(path, path->level))1960		return NULL;1961 1962	/* got to end? */1963	if (!btree_path_node(path, path->level + 1)) {1964		btree_path_set_level_up(trans, path);1965		return NULL;1966	}1967 1968	if (!bch2_btree_node_relock(trans, path, path->level + 1)) {1969		__bch2_btree_path_unlock(trans, path);1970		path->l[path->level].b		= ERR_PTR(-BCH_ERR_no_btree_node_relock);1971		path->l[path->level + 1].b	= ERR_PTR(-BCH_ERR_no_btree_node_relock);1972		btree_path_set_dirty(path, BTREE_ITER_NEED_TRAVERSE);1973		trace_and_count(trans->c, trans_restart_relock_next_node, trans, _THIS_IP_, path);1974		ret = btree_trans_restart(trans, BCH_ERR_transaction_restart_relock);1975		goto err;1976	}1977 1978	b = btree_path_node(path, path->level + 1);1979 1980	if (bpos_eq(iter->pos, b->key.k.p)) {1981		__btree_path_set_level_up(trans, path, path->level++);1982	} else {1983		if (btree_lock_want(path, path->level + 1) == BTREE_NODE_UNLOCKED)1984			btree_node_unlock(trans, path, path->level + 1);1985 1986		/*1987		 * Haven't gotten to the end of the parent node: go back down to1988		 * the next child node1989		 */1990		iter->path = bch2_btree_path_set_pos(trans, iter->path,1991					bpos_successor(iter->pos),1992					iter->flags & BTREE_ITER_intent,1993					btree_iter_ip_allocated(iter));1994 1995		path = btree_iter_path(trans, iter);1996		btree_path_set_level_down(trans, path, iter->min_depth);1997 1998		ret = bch2_btree_path_traverse(trans, iter->path, iter->flags);1999		if (ret)2000			goto err;2001 2002		path = btree_iter_path(trans, iter);2003		b = path->l[path->level].b;2004	}2005 2006	bkey_init(&iter->k);2007	iter->k.p = iter->pos = b->key.k.p;2008 2009	iter->path = bch2_btree_path_set_pos(trans, iter->path, b->key.k.p,2010					iter->flags & BTREE_ITER_intent,2011					btree_iter_ip_allocated(iter));2012	btree_path_set_should_be_locked(trans, btree_iter_path(trans, iter));2013	EBUG_ON(btree_iter_path(trans, iter)->uptodate);2014out:2015	bch2_btree_iter_verify_entry_exit(iter);2016	bch2_btree_iter_verify(iter);2017 2018	return b;2019err:2020	b = ERR_PTR(ret);2021	goto out;2022}2023 2024/* Iterate across keys (in leaf nodes only) */2025 2026inline bool bch2_btree_iter_advance(struct btree_iter *iter)2027{2028	struct bpos pos = iter->k.p;2029	bool ret = !(iter->flags & BTREE_ITER_all_snapshots2030		     ? bpos_eq(pos, SPOS_MAX)2031		     : bkey_eq(pos, SPOS_MAX));2032 2033	if (ret && !(iter->flags & BTREE_ITER_is_extents))2034		pos = bkey_successor(iter, pos);2035	bch2_btree_iter_set_pos(iter, pos);2036	return ret;2037}2038 2039inline bool bch2_btree_iter_rewind(struct btree_iter *iter)2040{2041	struct bpos pos = bkey_start_pos(&iter->k);2042	bool ret = !(iter->flags & BTREE_ITER_all_snapshots2043		     ? bpos_eq(pos, POS_MIN)2044		     : bkey_eq(pos, POS_MIN));2045 2046	if (ret && !(iter->flags & BTREE_ITER_is_extents))2047		pos = bkey_predecessor(iter, pos);2048	bch2_btree_iter_set_pos(iter, pos);2049	return ret;2050}2051 2052static noinline2053void bch2_btree_trans_peek_prev_updates(struct btree_trans *trans, struct btree_iter *iter,2054					struct bkey_s_c *k)2055{2056	struct bpos end = path_l(btree_iter_path(trans, iter))->b->data->min_key;2057 2058	trans_for_each_update(trans, i)2059		if (!i->key_cache_already_flushed &&2060		    i->btree_id == iter->btree_id &&2061		    bpos_le(i->k->k.p, iter->pos) &&2062		    bpos_ge(i->k->k.p, k->k ? k->k->p : end)) {2063			iter->k = i->k->k;2064			*k = bkey_i_to_s_c(i->k);2065		}2066}2067 2068static noinline2069void bch2_btree_trans_peek_updates(struct btree_trans *trans, struct btree_iter *iter,2070				   struct bkey_s_c *k)2071{2072	struct btree_path *path = btree_iter_path(trans, iter);2073	struct bpos end = path_l(path)->b->key.k.p;2074 2075	trans_for_each_update(trans, i)2076		if (!i->key_cache_already_flushed &&2077		    i->btree_id == iter->btree_id &&2078		    bpos_ge(i->k->k.p, path->pos) &&2079		    bpos_le(i->k->k.p, k->k ? k->k->p : end)) {2080			iter->k = i->k->k;2081			*k = bkey_i_to_s_c(i->k);2082		}2083}2084 2085static noinline2086void bch2_btree_trans_peek_slot_updates(struct btree_trans *trans, struct btree_iter *iter,2087					struct bkey_s_c *k)2088{2089	trans_for_each_update(trans, i)2090		if (!i->key_cache_already_flushed &&2091		    i->btree_id == iter->btree_id &&2092		    bpos_eq(i->k->k.p, iter->pos)) {2093			iter->k = i->k->k;2094			*k = bkey_i_to_s_c(i->k);2095		}2096}2097 2098static struct bkey_i *bch2_btree_journal_peek(struct btree_trans *trans,2099					      struct btree_iter *iter,2100					      struct bpos end_pos)2101{2102	struct btree_path *path = btree_iter_path(trans, iter);2103 2104	return bch2_journal_keys_peek_upto(trans->c, iter->btree_id,2105					   path->level,2106					   path->pos,2107					   end_pos,2108					   &iter->journal_idx);2109}2110 2111static noinline2112struct bkey_s_c btree_trans_peek_slot_journal(struct btree_trans *trans,2113					      struct btree_iter *iter)2114{2115	struct btree_path *path = btree_iter_path(trans, iter);2116	struct bkey_i *k = bch2_btree_journal_peek(trans, iter, path->pos);2117 2118	if (k) {2119		iter->k = k->k;2120		return bkey_i_to_s_c(k);2121	} else {2122		return bkey_s_c_null;2123	}2124}2125 2126static noinline2127struct bkey_s_c btree_trans_peek_journal(struct btree_trans *trans,2128					 struct btree_iter *iter,2129					 struct bkey_s_c k)2130{2131	struct btree_path *path = btree_iter_path(trans, iter);2132	struct bkey_i *next_journal =2133		bch2_btree_journal_peek(trans, iter,2134				k.k ? k.k->p : path_l(path)->b->key.k.p);2135 2136	if (next_journal) {2137		iter->k = next_journal->k;2138		k = bkey_i_to_s_c(next_journal);2139	}2140 2141	return k;2142}2143 2144/*2145 * Checks btree key cache for key at iter->pos and returns it if present, or2146 * bkey_s_c_null:2147 */2148static noinline2149struct bkey_s_c btree_trans_peek_key_cache(struct btree_iter *iter, struct bpos pos)2150{2151	struct btree_trans *trans = iter->trans;2152	struct bch_fs *c = trans->c;2153	struct bkey u;2154	struct bkey_s_c k;2155	int ret;2156 2157	bch2_trans_verify_not_in_restart(trans);2158	bch2_trans_verify_not_unlocked(trans);2159 2160	if ((iter->flags & BTREE_ITER_key_cache_fill) &&2161	    bpos_eq(iter->pos, pos))2162		return bkey_s_c_null;2163 2164	if (!bch2_btree_key_cache_find(c, iter->btree_id, pos))2165		return bkey_s_c_null;2166 2167	if (!iter->key_cache_path)2168		iter->key_cache_path = bch2_path_get(trans, iter->btree_id, pos,2169						     iter->flags & BTREE_ITER_intent, 0,2170						     iter->flags|BTREE_ITER_cached|2171						     BTREE_ITER_cached_nofill,2172						     _THIS_IP_);2173 2174	iter->key_cache_path = bch2_btree_path_set_pos(trans, iter->key_cache_path, pos,2175					iter->flags & BTREE_ITER_intent,2176					btree_iter_ip_allocated(iter));2177 2178	ret =   bch2_btree_path_traverse(trans, iter->key_cache_path,2179					 iter->flags|BTREE_ITER_cached) ?:2180		bch2_btree_path_relock(trans, btree_iter_path(trans, iter), _THIS_IP_);2181	if (unlikely(ret))2182		return bkey_s_c_err(ret);2183 2184	btree_path_set_should_be_locked(trans, trans->paths + iter->key_cache_path);2185 2186	k = bch2_btree_path_peek_slot(trans->paths + iter->key_cache_path, &u);2187	if (k.k && !bkey_err(k)) {2188		iter->k = u;2189		k.k = &iter->k;2190	}2191	return k;2192}2193 2194static struct bkey_s_c __bch2_btree_iter_peek(struct btree_iter *iter, struct bpos search_key)2195{2196	struct btree_trans *trans = iter->trans;2197	struct bkey_s_c k, k2;2198	int ret;2199 2200	EBUG_ON(btree_iter_path(trans, iter)->cached);2201	bch2_btree_iter_verify(iter);2202 2203	while (1) {2204		struct btree_path_level *l;2205 2206		iter->path = bch2_btree_path_set_pos(trans, iter->path, search_key,2207					iter->flags & BTREE_ITER_intent,2208					btree_iter_ip_allocated(iter));2209 2210		ret = bch2_btree_path_traverse(trans, iter->path, iter->flags);2211		if (unlikely(ret)) {2212			/* ensure that iter->k is consistent with iter->pos: */2213			bch2_btree_iter_set_pos(iter, iter->pos);2214			k = bkey_s_c_err(ret);2215			goto out;2216		}2217 2218		struct btree_path *path = btree_iter_path(trans, iter);2219		l = path_l(path);2220 2221		if (unlikely(!l->b)) {2222			/* No btree nodes at requested level: */2223			bch2_btree_iter_set_pos(iter, SPOS_MAX);2224			k = bkey_s_c_null;2225			goto out;2226		}2227 2228		btree_path_set_should_be_locked(trans, path);2229 2230		k = btree_path_level_peek_all(trans->c, l, &iter->k);2231 2232		if (unlikely(iter->flags & BTREE_ITER_with_key_cache) &&2233		    k.k &&2234		    (k2 = btree_trans_peek_key_cache(iter, k.k->p)).k) {2235			k = k2;2236			ret = bkey_err(k);2237			if (ret) {2238				bch2_btree_iter_set_pos(iter, iter->pos);2239				goto out;2240			}2241		}2242 2243		if (unlikely(iter->flags & BTREE_ITER_with_journal))2244			k = btree_trans_peek_journal(trans, iter, k);2245 2246		if (unlikely((iter->flags & BTREE_ITER_with_updates) &&2247			     trans->nr_updates))2248			bch2_btree_trans_peek_updates(trans, iter, &k);2249 2250		if (k.k && bkey_deleted(k.k)) {2251			/*2252			 * If we've got a whiteout, and it's after the search2253			 * key, advance the search key to the whiteout instead2254			 * of just after the whiteout - it might be a btree2255			 * whiteout, with a real key at the same position, since2256			 * in the btree deleted keys sort before non deleted.2257			 */2258			search_key = !bpos_eq(search_key, k.k->p)2259				? k.k->p2260				: bpos_successor(k.k->p);2261			continue;2262		}2263 2264		if (likely(k.k)) {2265			break;2266		} else if (likely(!bpos_eq(l->b->key.k.p, SPOS_MAX))) {2267			/* Advance to next leaf node: */2268			search_key = bpos_successor(l->b->key.k.p);2269		} else {2270			/* End of btree: */2271			bch2_btree_iter_set_pos(iter, SPOS_MAX);2272			k = bkey_s_c_null;2273			goto out;2274		}2275	}2276out:2277	bch2_btree_iter_verify(iter);2278 2279	return k;2280}2281 2282/**2283 * bch2_btree_iter_peek_upto() - returns first key greater than or equal to2284 * iterator's current position2285 * @iter:	iterator to peek from2286 * @end:	search limit: returns keys less than or equal to @end2287 *2288 * Returns:	key if found, or an error extractable with bkey_err().2289 */2290struct bkey_s_c bch2_btree_iter_peek_upto(struct btree_iter *iter, struct bpos end)2291{2292	struct btree_trans *trans = iter->trans;2293	struct bpos search_key = btree_iter_search_key(iter);2294	struct bkey_s_c k;2295	struct bpos iter_pos;2296	int ret;2297 2298	bch2_trans_verify_not_unlocked(trans);2299	EBUG_ON((iter->flags & BTREE_ITER_filter_snapshots) && bkey_eq(end, POS_MAX));2300 2301	if (iter->update_path) {2302		bch2_path_put_nokeep(trans, iter->update_path,2303				     iter->flags & BTREE_ITER_intent);2304		iter->update_path = 0;2305	}2306 2307	bch2_btree_iter_verify_entry_exit(iter);2308 2309	while (1) {2310		k = __bch2_btree_iter_peek(iter, search_key);2311		if (unlikely(!k.k))2312			goto end;2313		if (unlikely(bkey_err(k)))2314			goto out_no_locked;2315 2316		/*2317		 * We need to check against @end before FILTER_SNAPSHOTS because2318		 * if we get to a different inode that requested we might be2319		 * seeing keys for a different snapshot tree that will all be2320		 * filtered out.2321		 *2322		 * But we can't do the full check here, because bkey_start_pos()2323		 * isn't monotonically increasing before FILTER_SNAPSHOTS, and2324		 * that's what we check against in extents mode:2325		 */2326		if (unlikely(!(iter->flags & BTREE_ITER_is_extents)2327			     ? bkey_gt(k.k->p, end)2328			     : k.k->p.inode > end.inode))2329			goto end;2330 2331		if (iter->update_path &&2332		    !bkey_eq(trans->paths[iter->update_path].pos, k.k->p)) {2333			bch2_path_put_nokeep(trans, iter->update_path,2334					     iter->flags & BTREE_ITER_intent);2335			iter->update_path = 0;2336		}2337 2338		if ((iter->flags & BTREE_ITER_filter_snapshots) &&2339		    (iter->flags & BTREE_ITER_intent) &&2340		    !(iter->flags & BTREE_ITER_is_extents) &&2341		    !iter->update_path) {2342			struct bpos pos = k.k->p;2343 2344			if (pos.snapshot < iter->snapshot) {2345				search_key = bpos_successor(k.k->p);2346				continue;2347			}2348 2349			pos.snapshot = iter->snapshot;2350 2351			/*2352			 * advance, same as on exit for iter->path, but only up2353			 * to snapshot2354			 */2355			__btree_path_get(trans, trans->paths + iter->path, iter->flags & BTREE_ITER_intent);2356			iter->update_path = iter->path;2357 2358			iter->update_path = bch2_btree_path_set_pos(trans,2359						iter->update_path, pos,2360						iter->flags & BTREE_ITER_intent,2361						_THIS_IP_);2362			ret = bch2_btree_path_traverse(trans, iter->update_path, iter->flags);2363			if (unlikely(ret)) {2364				k = bkey_s_c_err(ret);2365				goto out_no_locked;2366			}2367		}2368 2369		/*2370		 * We can never have a key in a leaf node at POS_MAX, so2371		 * we don't have to check these successor() calls:2372		 */2373		if ((iter->flags & BTREE_ITER_filter_snapshots) &&2374		    !bch2_snapshot_is_ancestor(trans->c,2375					       iter->snapshot,2376					       k.k->p.snapshot)) {2377			search_key = bpos_successor(k.k->p);2378			continue;2379		}2380 2381		if (bkey_whiteout(k.k) &&2382		    !(iter->flags & BTREE_ITER_all_snapshots)) {2383			search_key = bkey_successor(iter, k.k->p);2384			continue;2385		}2386 2387		/*2388		 * iter->pos should be mononotically increasing, and always be2389		 * equal to the key we just returned - except extents can2390		 * straddle iter->pos:2391		 */2392		if (!(iter->flags & BTREE_ITER_is_extents))2393			iter_pos = k.k->p;2394		else2395			iter_pos = bkey_max(iter->pos, bkey_start_pos(k.k));2396 2397		if (unlikely(iter->flags & BTREE_ITER_all_snapshots	? bpos_gt(iter_pos, end) :2398			     iter->flags & BTREE_ITER_is_extents	? bkey_ge(iter_pos, end) :2399									  bkey_gt(iter_pos, end)))2400			goto end;2401 2402		break;2403	}2404 2405	iter->pos = iter_pos;2406 2407	iter->path = bch2_btree_path_set_pos(trans, iter->path, k.k->p,2408				iter->flags & BTREE_ITER_intent,2409				btree_iter_ip_allocated(iter));2410 2411	btree_path_set_should_be_locked(trans, btree_iter_path(trans, iter));2412out_no_locked:2413	if (iter->update_path) {2414		ret = bch2_btree_path_relock(trans, trans->paths + iter->update_path, _THIS_IP_);2415		if (unlikely(ret))2416			k = bkey_s_c_err(ret);2417		else2418			btree_path_set_should_be_locked(trans, trans->paths + iter->update_path);2419	}2420 2421	if (!(iter->flags & BTREE_ITER_all_snapshots))2422		iter->pos.snapshot = iter->snapshot;2423 2424	ret = bch2_btree_iter_verify_ret(iter, k);2425	if (unlikely(ret)) {2426		bch2_btree_iter_set_pos(iter, iter->pos);2427		k = bkey_s_c_err(ret);2428	}2429 2430	bch2_btree_iter_verify_entry_exit(iter);2431 2432	return k;2433end:2434	bch2_btree_iter_set_pos(iter, end);2435	k = bkey_s_c_null;2436	goto out_no_locked;2437}2438 2439/**2440 * bch2_btree_iter_next() - returns first key greater than iterator's current2441 * position2442 * @iter:	iterator to peek from2443 *2444 * Returns:	key if found, or an error extractable with bkey_err().2445 */2446struct bkey_s_c bch2_btree_iter_next(struct btree_iter *iter)2447{2448	if (!bch2_btree_iter_advance(iter))2449		return bkey_s_c_null;2450 2451	return bch2_btree_iter_peek(iter);2452}2453 2454/**2455 * bch2_btree_iter_peek_prev() - returns first key less than or equal to2456 * iterator's current position2457 * @iter:	iterator to peek from2458 *2459 * Returns:	key if found, or an error extractable with bkey_err().2460 */2461struct bkey_s_c bch2_btree_iter_peek_prev(struct btree_iter *iter)2462{2463	struct btree_trans *trans = iter->trans;2464	struct bpos search_key = iter->pos;2465	struct bkey_s_c k;2466	struct bkey saved_k;2467	const struct bch_val *saved_v;2468	btree_path_idx_t saved_path = 0;2469	int ret;2470 2471	bch2_trans_verify_not_unlocked(trans);2472	EBUG_ON(btree_iter_path(trans, iter)->cached ||2473		btree_iter_path(trans, iter)->level);2474 2475	if (iter->flags & BTREE_ITER_with_journal)2476		return bkey_s_c_err(-BCH_ERR_btree_iter_with_journal_not_supported);2477 2478	bch2_btree_iter_verify(iter);2479	bch2_btree_iter_verify_entry_exit(iter);2480 2481	if (iter->flags & BTREE_ITER_filter_snapshots)2482		search_key.snapshot = U32_MAX;2483 2484	while (1) {2485		iter->path = bch2_btree_path_set_pos(trans, iter->path, search_key,2486						iter->flags & BTREE_ITER_intent,2487						btree_iter_ip_allocated(iter));2488 2489		ret = bch2_btree_path_traverse(trans, iter->path, iter->flags);2490		if (unlikely(ret)) {2491			/* ensure that iter->k is consistent with iter->pos: */2492			bch2_btree_iter_set_pos(iter, iter->pos);2493			k = bkey_s_c_err(ret);2494			goto out_no_locked;2495		}2496 2497		struct btree_path *path = btree_iter_path(trans, iter);2498 2499		k = btree_path_level_peek(trans, path, &path->l[0], &iter->k);2500		if (!k.k ||2501		    ((iter->flags & BTREE_ITER_is_extents)2502		     ? bpos_ge(bkey_start_pos(k.k), search_key)2503		     : bpos_gt(k.k->p, search_key)))2504			k = btree_path_level_prev(trans, path, &path->l[0], &iter->k);2505 2506		if (unlikely((iter->flags & BTREE_ITER_with_updates) &&2507			     trans->nr_updates))2508			bch2_btree_trans_peek_prev_updates(trans, iter, &k);2509 2510		if (likely(k.k)) {2511			if (iter->flags & BTREE_ITER_filter_snapshots) {2512				if (k.k->p.snapshot == iter->snapshot)2513					goto got_key;2514 2515				/*2516				 * If we have a saved candidate, and we're no2517				 * longer at the same _key_ (not pos), return2518				 * that candidate2519				 */2520				if (saved_path && !bkey_eq(k.k->p, saved_k.p)) {2521					bch2_path_put_nokeep(trans, iter->path,2522						      iter->flags & BTREE_ITER_intent);2523					iter->path = saved_path;2524					saved_path = 0;2525					iter->k	= saved_k;2526					k.v	= saved_v;2527					goto got_key;2528				}2529 2530				if (bch2_snapshot_is_ancestor(trans->c,2531							      iter->snapshot,2532							      k.k->p.snapshot)) {2533					if (saved_path)2534						bch2_path_put_nokeep(trans, saved_path,2535						      iter->flags & BTREE_ITER_intent);2536					saved_path = btree_path_clone(trans, iter->path,2537								iter->flags & BTREE_ITER_intent,2538								_THIS_IP_);2539					path = btree_iter_path(trans, iter);2540					trace_btree_path_save_pos(trans, path, trans->paths + saved_path);2541					saved_k = *k.k;2542					saved_v = k.v;2543				}2544 2545				search_key = bpos_predecessor(k.k->p);2546				continue;2547			}2548got_key:2549			if (bkey_whiteout(k.k) &&2550			    !(iter->flags & BTREE_ITER_all_snapshots)) {2551				search_key = bkey_predecessor(iter, k.k->p);2552				if (iter->flags & BTREE_ITER_filter_snapshots)2553					search_key.snapshot = U32_MAX;2554				continue;2555			}2556 2557			btree_path_set_should_be_locked(trans, path);2558			break;2559		} else if (likely(!bpos_eq(path->l[0].b->data->min_key, POS_MIN))) {2560			/* Advance to previous leaf node: */2561			search_key = bpos_predecessor(path->l[0].b->data->min_key);2562		} else {2563			/* Start of btree: */2564			bch2_btree_iter_set_pos(iter, POS_MIN);2565			k = bkey_s_c_null;2566			goto out_no_locked;2567		}2568	}2569 2570	EBUG_ON(bkey_gt(bkey_start_pos(k.k), iter->pos));2571 2572	/* Extents can straddle iter->pos: */2573	if (bkey_lt(k.k->p, iter->pos))2574		iter->pos = k.k->p;2575 2576	if (iter->flags & BTREE_ITER_filter_snapshots)2577		iter->pos.snapshot = iter->snapshot;2578out_no_locked:2579	if (saved_path)2580		bch2_path_put_nokeep(trans, saved_path, iter->flags & BTREE_ITER_intent);2581 2582	bch2_btree_iter_verify_entry_exit(iter);2583	bch2_btree_iter_verify(iter);2584 2585	return k;2586}2587 2588/**2589 * bch2_btree_iter_prev() - returns first key less than iterator's current2590 * position2591 * @iter:	iterator to peek from2592 *2593 * Returns:	key if found, or an error extractable with bkey_err().2594 */2595struct bkey_s_c bch2_btree_iter_prev(struct btree_iter *iter)2596{2597	if (!bch2_btree_iter_rewind(iter))2598		return bkey_s_c_null;2599 2600	return bch2_btree_iter_peek_prev(iter);2601}2602 2603struct bkey_s_c bch2_btree_iter_peek_slot(struct btree_iter *iter)2604{2605	struct btree_trans *trans = iter->trans;2606	struct bpos search_key;2607	struct bkey_s_c k;2608	int ret;2609 2610	bch2_trans_verify_not_unlocked(trans);2611	bch2_btree_iter_verify(iter);2612	bch2_btree_iter_verify_entry_exit(iter);2613	EBUG_ON(btree_iter_path(trans, iter)->level && (iter->flags & BTREE_ITER_with_key_cache));2614 2615	/* extents can't span inode numbers: */2616	if ((iter->flags & BTREE_ITER_is_extents) &&2617	    unlikely(iter->pos.offset == KEY_OFFSET_MAX)) {2618		if (iter->pos.inode == KEY_INODE_MAX)2619			return bkey_s_c_null;2620 2621		bch2_btree_iter_set_pos(iter, bpos_nosnap_successor(iter->pos));2622	}2623 2624	search_key = btree_iter_search_key(iter);2625	iter->path = bch2_btree_path_set_pos(trans, iter->path, search_key,2626					iter->flags & BTREE_ITER_intent,2627					btree_iter_ip_allocated(iter));2628 2629	ret = bch2_btree_path_traverse(trans, iter->path, iter->flags);2630	if (unlikely(ret)) {2631		k = bkey_s_c_err(ret);2632		goto out_no_locked;2633	}2634 2635	if ((iter->flags & BTREE_ITER_cached) ||2636	    !(iter->flags & (BTREE_ITER_is_extents|BTREE_ITER_filter_snapshots))) {2637		k = bkey_s_c_null;2638 2639		if (unlikely((iter->flags & BTREE_ITER_with_updates) &&2640			     trans->nr_updates)) {2641			bch2_btree_trans_peek_slot_updates(trans, iter, &k);2642			if (k.k)2643				goto out;2644		}2645 2646		if (unlikely(iter->flags & BTREE_ITER_with_journal) &&2647		    (k = btree_trans_peek_slot_journal(trans, iter)).k)2648			goto out;2649 2650		if (unlikely(iter->flags & BTREE_ITER_with_key_cache) &&2651		    (k = btree_trans_peek_key_cache(iter, iter->pos)).k) {2652			if (!bkey_err(k))2653				iter->k = *k.k;2654			/* We're not returning a key from iter->path: */2655			goto out_no_locked;2656		}2657 2658		k = bch2_btree_path_peek_slot(trans->paths + iter->path, &iter->k);2659		if (unlikely(!k.k))2660			goto out_no_locked;2661	} else {2662		struct bpos next;2663		struct bpos end = iter->pos;2664 2665		if (iter->flags & BTREE_ITER_is_extents)2666			end.offset = U64_MAX;2667 2668		EBUG_ON(btree_iter_path(trans, iter)->level);2669 2670		if (iter->flags & BTREE_ITER_intent) {2671			struct btree_iter iter2;2672 2673			bch2_trans_copy_iter(&iter2, iter);2674			k = bch2_btree_iter_peek_upto(&iter2, end);2675 2676			if (k.k && !bkey_err(k)) {2677				swap(iter->key_cache_path, iter2.key_cache_path);2678				iter->k = iter2.k;2679				k.k = &iter->k;2680			}2681			bch2_trans_iter_exit(trans, &iter2);2682		} else {2683			struct bpos pos = iter->pos;2684 2685			k = bch2_btree_iter_peek_upto(iter, end);2686			if (unlikely(bkey_err(k)))2687				bch2_btree_iter_set_pos(iter, pos);2688			else2689				iter->pos = pos;2690		}2691 2692		if (unlikely(bkey_err(k)))2693			goto out_no_locked;2694 2695		next = k.k ? bkey_start_pos(k.k) : POS_MAX;2696 2697		if (bkey_lt(iter->pos, next)) {2698			bkey_init(&iter->k);2699			iter->k.p = iter->pos;2700 2701			if (iter->flags & BTREE_ITER_is_extents) {2702				bch2_key_resize(&iter->k,2703						min_t(u64, KEY_SIZE_MAX,2704						      (next.inode == iter->pos.inode2705						       ? next.offset2706						       : KEY_OFFSET_MAX) -2707						      iter->pos.offset));2708				EBUG_ON(!iter->k.size);2709			}2710 2711			k = (struct bkey_s_c) { &iter->k, NULL };2712		}2713	}2714out:2715	btree_path_set_should_be_locked(trans, btree_iter_path(trans, iter));2716out_no_locked:2717	bch2_btree_iter_verify_entry_exit(iter);2718	bch2_btree_iter_verify(iter);2719	ret = bch2_btree_iter_verify_ret(iter, k);2720	if (unlikely(ret))2721		return bkey_s_c_err(ret);2722 2723	return k;2724}2725 2726struct bkey_s_c bch2_btree_iter_next_slot(struct btree_iter *iter)2727{2728	if (!bch2_btree_iter_advance(iter))2729		return bkey_s_c_null;2730 2731	return bch2_btree_iter_peek_slot(iter);2732}2733 2734struct bkey_s_c bch2_btree_iter_prev_slot(struct btree_iter *iter)2735{2736	if (!bch2_btree_iter_rewind(iter))2737		return bkey_s_c_null;2738 2739	return bch2_btree_iter_peek_slot(iter);2740}2741 2742/* Obsolete, but still used by rust wrapper in -tools */2743struct bkey_s_c bch2_btree_iter_peek_and_restart_outlined(struct btree_iter *iter)2744{2745	struct bkey_s_c k;2746 2747	while (btree_trans_too_many_iters(iter->trans) ||2748	       (k = bch2_btree_iter_peek_type(iter, iter->flags),2749		bch2_err_matches(bkey_err(k), BCH_ERR_transaction_restart)))2750		bch2_trans_begin(iter->trans);2751 2752	return k;2753}2754 2755/* new transactional stuff: */2756 2757#ifdef CONFIG_BCACHEFS_DEBUG2758static void btree_trans_verify_sorted_refs(struct btree_trans *trans)2759{2760	struct btree_path *path;2761	unsigned i;2762 2763	BUG_ON(trans->nr_sorted != bitmap_weight(trans->paths_allocated, trans->nr_paths) - 1);2764 2765	trans_for_each_path(trans, path, i) {2766		BUG_ON(path->sorted_idx >= trans->nr_sorted);2767		BUG_ON(trans->sorted[path->sorted_idx] != i);2768	}2769 2770	for (i = 0; i < trans->nr_sorted; i++) {2771		unsigned idx = trans->sorted[i];2772 2773		BUG_ON(!test_bit(idx, trans->paths_allocated));2774		BUG_ON(trans->paths[idx].sorted_idx != i);2775	}2776}2777 2778static void btree_trans_verify_sorted(struct btree_trans *trans)2779{2780	struct btree_path *path, *prev = NULL;2781	struct trans_for_each_path_inorder_iter iter;2782 2783	if (!bch2_debug_check_iterators)2784		return;2785 2786	trans_for_each_path_inorder(trans, path, iter) {2787		if (prev && btree_path_cmp(prev, path) > 0) {2788			__bch2_dump_trans_paths_updates(trans, true);2789			panic("trans paths out of order!\n");2790		}2791		prev = path;2792	}2793}2794#else2795static inline void btree_trans_verify_sorted_refs(struct btree_trans *trans) {}2796static inline void btree_trans_verify_sorted(struct btree_trans *trans) {}2797#endif2798 2799void __bch2_btree_trans_sort_paths(struct btree_trans *trans)2800{2801	int i, l = 0, r = trans->nr_sorted, inc = 1;2802	bool swapped;2803 2804	btree_trans_verify_sorted_refs(trans);2805 2806	if (trans->paths_sorted)2807		goto out;2808 2809	/*2810	 * Cocktail shaker sort: this is efficient because iterators will be2811	 * mostly sorted.2812	 */2813	do {2814		swapped = false;2815 2816		for (i = inc > 0 ? l : r - 2;2817		     i + 1 < r && i >= l;2818		     i += inc) {2819			if (btree_path_cmp(trans->paths + trans->sorted[i],2820					   trans->paths + trans->sorted[i + 1]) > 0) {2821				swap(trans->sorted[i], trans->sorted[i + 1]);2822				trans->paths[trans->sorted[i]].sorted_idx = i;2823				trans->paths[trans->sorted[i + 1]].sorted_idx = i + 1;2824				swapped = true;2825			}2826		}2827 2828		if (inc > 0)2829			--r;2830		else2831			l++;2832		inc = -inc;2833	} while (swapped);2834 2835	trans->paths_sorted = true;2836out:2837	btree_trans_verify_sorted(trans);2838}2839 2840static inline void btree_path_list_remove(struct btree_trans *trans,2841					  struct btree_path *path)2842{2843	EBUG_ON(path->sorted_idx >= trans->nr_sorted);2844#ifdef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS2845	trans->nr_sorted--;2846	memmove_u64s_down_small(trans->sorted + path->sorted_idx,2847				trans->sorted + path->sorted_idx + 1,2848				DIV_ROUND_UP(trans->nr_sorted - path->sorted_idx,2849					     sizeof(u64) / sizeof(btree_path_idx_t)));2850#else2851	array_remove_item(trans->sorted, trans->nr_sorted, path->sorted_idx);2852#endif2853	for (unsigned i = path->sorted_idx; i < trans->nr_sorted; i++)2854		trans->paths[trans->sorted[i]].sorted_idx = i;2855}2856 2857static inline void btree_path_list_add(struct btree_trans *trans,2858				       btree_path_idx_t pos,2859				       btree_path_idx_t path_idx)2860{2861	struct btree_path *path = trans->paths + path_idx;2862 2863	path->sorted_idx = pos ? trans->paths[pos].sorted_idx + 1 : trans->nr_sorted;2864 2865#ifdef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS2866	memmove_u64s_up_small(trans->sorted + path->sorted_idx + 1,2867			      trans->sorted + path->sorted_idx,2868			      DIV_ROUND_UP(trans->nr_sorted - path->sorted_idx,2869					   sizeof(u64) / sizeof(btree_path_idx_t)));2870	trans->nr_sorted++;2871	trans->sorted[path->sorted_idx] = path_idx;2872#else2873	array_insert_item(trans->sorted, trans->nr_sorted, path->sorted_idx, path_idx);2874#endif2875 2876	for (unsigned i = path->sorted_idx; i < trans->nr_sorted; i++)2877		trans->paths[trans->sorted[i]].sorted_idx = i;2878 2879	btree_trans_verify_sorted_refs(trans);2880}2881 2882void bch2_trans_iter_exit(struct btree_trans *trans, struct btree_iter *iter)2883{2884	if (iter->update_path)2885		bch2_path_put_nokeep(trans, iter->update_path,2886			      iter->flags & BTREE_ITER_intent);2887	if (iter->path)2888		bch2_path_put(trans, iter->path,2889			      iter->flags & BTREE_ITER_intent);2890	if (iter->key_cache_path)2891		bch2_path_put(trans, iter->key_cache_path,2892			      iter->flags & BTREE_ITER_intent);2893	iter->path		= 0;2894	iter->update_path	= 0;2895	iter->key_cache_path	= 0;2896	iter->trans		= NULL;2897}2898 2899void bch2_trans_iter_init_outlined(struct btree_trans *trans,2900			  struct btree_iter *iter,2901			  enum btree_id btree_id, struct bpos pos,2902			  unsigned flags)2903{2904	bch2_trans_iter_init_common(trans, iter, btree_id, pos, 0, 0,2905			       bch2_btree_iter_flags(trans, btree_id, flags),2906			       _RET_IP_);2907}2908 2909void bch2_trans_node_iter_init(struct btree_trans *trans,2910			       struct btree_iter *iter,2911			       enum btree_id btree_id,2912			       struct bpos pos,2913			       unsigned locks_want,2914			       unsigned depth,2915			       unsigned flags)2916{2917	flags |= BTREE_ITER_not_extents;2918	flags |= BTREE_ITER_snapshot_field;2919	flags |= BTREE_ITER_all_snapshots;2920 2921	bch2_trans_iter_init_common(trans, iter, btree_id, pos, locks_want, depth,2922			       __bch2_btree_iter_flags(trans, btree_id, flags),2923			       _RET_IP_);2924 2925	iter->min_depth	= depth;2926 2927	struct btree_path *path = btree_iter_path(trans, iter);2928	BUG_ON(path->locks_want	 < min(locks_want, BTREE_MAX_DEPTH));2929	BUG_ON(path->level	!= depth);2930	BUG_ON(iter->min_depth	!= depth);2931}2932 2933void bch2_trans_copy_iter(struct btree_iter *dst, struct btree_iter *src)2934{2935	struct btree_trans *trans = src->trans;2936 2937	*dst = *src;2938#ifdef TRACK_PATH_ALLOCATED2939	dst->ip_allocated = _RET_IP_;2940#endif2941	if (src->path)2942		__btree_path_get(trans, trans->paths + src->path, src->flags & BTREE_ITER_intent);2943	if (src->update_path)2944		__btree_path_get(trans, trans->paths + src->update_path, src->flags & BTREE_ITER_intent);2945	dst->key_cache_path = 0;2946}2947 2948void *__bch2_trans_kmalloc(struct btree_trans *trans, size_t size)2949{2950	struct bch_fs *c = trans->c;2951	unsigned new_top = trans->mem_top + size;2952	unsigned old_bytes = trans->mem_bytes;2953	unsigned new_bytes = roundup_pow_of_two(new_top);2954	int ret;2955	void *new_mem;2956	void *p;2957 2958	WARN_ON_ONCE(new_bytes > BTREE_TRANS_MEM_MAX);2959 2960	struct btree_transaction_stats *s = btree_trans_stats(trans);2961	s->max_mem = max(s->max_mem, new_bytes);2962 2963	if (trans->used_mempool) {2964		if (trans->mem_bytes >= new_bytes)2965			goto out_change_top;2966 2967		/* No more space from mempool item, need malloc new one */2968		new_mem = kmalloc(new_bytes, GFP_NOWAIT|__GFP_NOWARN);2969		if (unlikely(!new_mem)) {2970			bch2_trans_unlock(trans);2971 2972			new_mem = kmalloc(new_bytes, GFP_KERNEL);2973			if (!new_mem)2974				return ERR_PTR(-BCH_ERR_ENOMEM_trans_kmalloc);2975 2976			ret = bch2_trans_relock(trans);2977			if (ret) {2978				kfree(new_mem);2979				return ERR_PTR(ret);2980			}2981		}2982		memcpy(new_mem, trans->mem, trans->mem_top);2983		trans->used_mempool = false;2984		mempool_free(trans->mem, &c->btree_trans_mem_pool);2985		goto out_new_mem;2986	}2987 2988	new_mem = krealloc(trans->mem, new_bytes, GFP_NOWAIT|__GFP_NOWARN);2989	if (unlikely(!new_mem)) {2990		bch2_trans_unlock(trans);2991 2992		new_mem = krealloc(trans->mem, new_bytes, GFP_KERNEL);2993		if (!new_mem && new_bytes <= BTREE_TRANS_MEM_MAX) {2994			new_mem = mempool_alloc(&c->btree_trans_mem_pool, GFP_KERNEL);2995			new_bytes = BTREE_TRANS_MEM_MAX;2996			memcpy(new_mem, trans->mem, trans->mem_top);2997			trans->used_mempool = true;2998			kfree(trans->mem);2999		}3000 3001		if (!new_mem)3002			return ERR_PTR(-BCH_ERR_ENOMEM_trans_kmalloc);3003 3004		trans->mem = new_mem;3005		trans->mem_bytes = new_bytes;3006 3007		ret = bch2_trans_relock(trans);3008		if (ret)3009			return ERR_PTR(ret);3010	}3011out_new_mem:3012	trans->mem = new_mem;3013	trans->mem_bytes = new_bytes;3014 3015	if (old_bytes) {3016		trace_and_count(c, trans_restart_mem_realloced, trans, _RET_IP_, new_bytes);3017		return ERR_PTR(btree_trans_restart(trans, BCH_ERR_transaction_restart_mem_realloced));3018	}3019out_change_top:3020	p = trans->mem + trans->mem_top;3021	trans->mem_top += size;3022	memset(p, 0, size);3023	return p;3024}3025 3026static inline void check_srcu_held_too_long(struct btree_trans *trans)3027{3028	WARN(trans->srcu_held && time_after(jiffies, trans->srcu_lock_time + HZ * 10),3029	     "btree trans held srcu lock (delaying memory reclaim) for %lu seconds",3030	     (jiffies - trans->srcu_lock_time) / HZ);3031}3032 3033void bch2_trans_srcu_unlock(struct btree_trans *trans)3034{3035	if (trans->srcu_held) {3036		struct bch_fs *c = trans->c;3037		struct btree_path *path;3038		unsigned i;3039 3040		trans_for_each_path(trans, path, i)3041			if (path->cached && !btree_node_locked(path, 0))3042				path->l[0].b = ERR_PTR(-BCH_ERR_no_btree_node_srcu_reset);3043 3044		check_srcu_held_too_long(trans);3045		srcu_read_unlock(&c->btree_trans_barrier, trans->srcu_idx);3046		trans->srcu_held = false;3047	}3048}3049 3050static void bch2_trans_srcu_lock(struct btree_trans *trans)3051{3052	if (!trans->srcu_held) {3053		trans->srcu_idx = srcu_read_lock(&trans->c->btree_trans_barrier);3054		trans->srcu_lock_time	= jiffies;3055		trans->srcu_held = true;3056	}3057}3058 3059/**3060 * bch2_trans_begin() - reset a transaction after a interrupted attempt3061 * @trans: transaction to reset3062 *3063 * Returns:	current restart counter, to be used with trans_was_restarted()3064 *3065 * While iterating over nodes or updating nodes a attempt to lock a btree node3066 * may return BCH_ERR_transaction_restart when the trylock fails. When this3067 * occurs bch2_trans_begin() should be called and the transaction retried.3068 */3069u32 bch2_trans_begin(struct btree_trans *trans)3070{3071	struct btree_path *path;3072	unsigned i;3073	u64 now;3074 3075	bch2_trans_reset_updates(trans);3076 3077	trans->restart_count++;3078	trans->mem_top			= 0;3079	trans->journal_entries		= NULL;3080 3081	trans_for_each_path(trans, path, i) {3082		path->should_be_locked = false;3083 3084		/*3085		 * If the transaction wasn't restarted, we're presuming to be3086		 * doing something new: dont keep iterators excpt the ones that3087		 * are in use - except for the subvolumes btree:3088		 */3089		if (!trans->restarted && path->btree_id != BTREE_ID_subvolumes)3090			path->preserve = false;3091 3092		/*3093		 * XXX: we probably shouldn't be doing this if the transaction3094		 * was restarted, but currently we still overflow transaction3095		 * iterators if we do that3096		 */3097		if (!path->ref && !path->preserve)3098			__bch2_path_free(trans, i);3099		else3100			path->preserve = false;3101	}3102 3103	now = local_clock();3104 3105	if (!IS_ENABLED(CONFIG_BCACHEFS_NO_LATENCY_ACCT) &&3106	    time_after64(now, trans->last_begin_time + 10))3107		__bch2_time_stats_update(&btree_trans_stats(trans)->duration,3108					 trans->last_begin_time, now);3109 3110	if (!trans->restarted &&3111	    (need_resched() ||3112	     time_after64(now, trans->last_begin_time + BTREE_TRANS_MAX_LOCK_HOLD_TIME_NS))) {3113		bch2_trans_unlock(trans);3114		cond_resched();3115		now = local_clock();3116	}3117	trans->last_begin_time = now;3118 3119	if (unlikely(trans->srcu_held &&3120		     time_after(jiffies, trans->srcu_lock_time + msecs_to_jiffies(10))))3121		bch2_trans_srcu_unlock(trans);3122 3123	trans->last_begin_ip = _RET_IP_;3124 3125	trans_set_locked(trans);3126 3127	if (trans->restarted) {3128		bch2_btree_path_traverse_all(trans);3129		trans->notrace_relock_fail = false;3130	}3131 3132	bch2_trans_verify_not_unlocked(trans);3133	return trans->restart_count;3134}3135 3136const char *bch2_btree_transaction_fns[BCH_TRANSACTIONS_NR] = { "(unknown)" };3137 3138unsigned bch2_trans_get_fn_idx(const char *fn)3139{3140	for (unsigned i = 0; i < ARRAY_SIZE(bch2_btree_transaction_fns); i++)3141		if (!bch2_btree_transaction_fns[i] ||3142		    bch2_btree_transaction_fns[i] == fn) {3143			bch2_btree_transaction_fns[i] = fn;3144			return i;3145		}3146 3147	pr_warn_once("BCH_TRANSACTIONS_NR not big enough!");3148	return 0;3149}3150 3151struct btree_trans *__bch2_trans_get(struct bch_fs *c, unsigned fn_idx)3152	__acquires(&c->btree_trans_barrier)3153{3154	struct btree_trans *trans;3155 3156	if (IS_ENABLED(__KERNEL__)) {3157		trans = this_cpu_xchg(c->btree_trans_bufs->trans, NULL);3158		if (trans) {3159			memset(trans, 0, offsetof(struct btree_trans, list));3160			goto got_trans;3161		}3162	}3163 3164	trans = mempool_alloc(&c->btree_trans_pool, GFP_NOFS);3165	memset(trans, 0, sizeof(*trans));3166 3167	seqmutex_lock(&c->btree_trans_lock);3168	if (IS_ENABLED(CONFIG_BCACHEFS_DEBUG)) {3169		struct btree_trans *pos;3170		pid_t pid = current->pid;3171 3172		trans->locking_wait.task = current;3173 3174		list_for_each_entry(pos, &c->btree_trans_list, list) {3175			struct task_struct *pos_task = READ_ONCE(pos->locking_wait.task);3176			/*3177			 * We'd much prefer to be stricter here and completely3178			 * disallow multiple btree_trans in the same thread -3179			 * but the data move path calls bch2_write when we3180			 * already have a btree_trans initialized.3181			 */3182			BUG_ON(pos_task &&3183			       pid == pos_task->pid &&3184			       pos->locked);3185		}3186	}3187 3188	list_add(&trans->list, &c->btree_trans_list);3189	seqmutex_unlock(&c->btree_trans_lock);3190got_trans:3191	trans->c		= c;3192	trans->last_begin_time	= local_clock();3193	trans->fn_idx		= fn_idx;3194	trans->locking_wait.task = current;3195	trans->journal_replay_not_finished =3196		unlikely(!test_bit(JOURNAL_replay_done, &c->journal.flags)) &&3197		atomic_inc_not_zero(&c->journal_keys.ref);3198	trans->nr_paths		= ARRAY_SIZE(trans->_paths);3199	trans->paths_allocated	= trans->_paths_allocated;3200	trans->sorted		= trans->_sorted;3201	trans->paths		= trans->_paths;3202	trans->updates		= trans->_updates;3203 3204	*trans_paths_nr(trans->paths) = BTREE_ITER_INITIAL;3205 3206	trans->paths_allocated[0] = 1;3207 3208	static struct lock_class_key lockdep_key;3209	lockdep_init_map(&trans->dep_map, "bcachefs_btree", &lockdep_key, 0);3210 3211	if (fn_idx < BCH_TRANSACTIONS_NR) {3212		trans->fn = bch2_btree_transaction_fns[fn_idx];3213 3214		struct btree_transaction_stats *s = &c->btree_transaction_stats[fn_idx];3215 3216		if (s->max_mem) {3217			unsigned expected_mem_bytes = roundup_pow_of_two(s->max_mem);3218 3219			trans->mem = kmalloc(expected_mem_bytes, GFP_KERNEL);3220			if (likely(trans->mem))3221				trans->mem_bytes = expected_mem_bytes;3222		}3223 3224		trans->nr_paths_max = s->nr_max_paths;3225		trans->journal_entries_size = s->journal_entries_size;3226	}3227 3228	trans->srcu_idx		= srcu_read_lock(&c->btree_trans_barrier);3229	trans->srcu_lock_time	= jiffies;3230	trans->srcu_held	= true;3231	trans_set_locked(trans);3232 3233	closure_init_stack_release(&trans->ref);3234	return trans;3235}3236 3237static void check_btree_paths_leaked(struct btree_trans *trans)3238{3239#ifdef CONFIG_BCACHEFS_DEBUG3240	struct bch_fs *c = trans->c;3241	struct btree_path *path;3242	unsigned i;3243 3244	trans_for_each_path(trans, path, i)3245		if (path->ref)3246			goto leaked;3247	return;3248leaked:3249	bch_err(c, "btree paths leaked from %s!", trans->fn);3250	trans_for_each_path(trans, path, i)3251		if (path->ref)3252			printk(KERN_ERR "  btree %s %pS\n",3253			       bch2_btree_id_str(path->btree_id),3254			       (void *) path->ip_allocated);3255	/* Be noisy about this: */3256	bch2_fatal_error(c);3257#endif3258}3259 3260void bch2_trans_put(struct btree_trans *trans)3261	__releases(&c->btree_trans_barrier)3262{3263	struct bch_fs *c = trans->c;3264 3265	bch2_trans_unlock(trans);3266 3267	trans_for_each_update(trans, i)3268		__btree_path_put(trans, trans->paths + i->path, true);3269	trans->nr_updates	= 0;3270 3271	check_btree_paths_leaked(trans);3272 3273	if (trans->srcu_held) {3274		check_srcu_held_too_long(trans);3275		srcu_read_unlock(&c->btree_trans_barrier, trans->srcu_idx);3276	}3277 3278	if (unlikely(trans->journal_replay_not_finished))3279		bch2_journal_keys_put(c);3280 3281	/*3282	 * trans->ref protects trans->locking_wait.task, btree_paths array; used3283	 * by cycle detector3284	 */3285	closure_return_sync(&trans->ref);3286	trans->locking_wait.task = NULL;3287 3288	unsigned long *paths_allocated = trans->paths_allocated;3289	trans->paths_allocated	= NULL;3290	trans->paths		= NULL;3291 3292	if (paths_allocated != trans->_paths_allocated)3293		kvfree_rcu_mightsleep(paths_allocated);3294 3295	if (trans->used_mempool)3296		mempool_free(trans->mem, &c->btree_trans_mem_pool);3297	else3298		kfree(trans->mem);3299 3300	/* Userspace doesn't have a real percpu implementation: */3301	if (IS_ENABLED(__KERNEL__))3302		trans = this_cpu_xchg(c->btree_trans_bufs->trans, trans);3303 3304	if (trans) {3305		seqmutex_lock(&c->btree_trans_lock);3306		list_del(&trans->list);3307		seqmutex_unlock(&c->btree_trans_lock);3308 3309		mempool_free(trans, &c->btree_trans_pool);3310	}3311}3312 3313bool bch2_current_has_btree_trans(struct bch_fs *c)3314{3315	seqmutex_lock(&c->btree_trans_lock);3316	struct btree_trans *trans;3317	bool ret = false;3318	list_for_each_entry(trans, &c->btree_trans_list, list)3319		if (trans->locking_wait.task == current &&3320		    trans->locked) {3321			ret = true;3322			break;3323		}3324	seqmutex_unlock(&c->btree_trans_lock);3325	return ret;3326}3327 3328static void __maybe_unused3329bch2_btree_bkey_cached_common_to_text(struct printbuf *out,3330				      struct btree_bkey_cached_common *b)3331{3332	struct six_lock_count c = six_lock_counts(&b->lock);3333	struct task_struct *owner;3334	pid_t pid;3335 3336	rcu_read_lock();3337	owner = READ_ONCE(b->lock.owner);3338	pid = owner ? owner->pid : 0;3339	rcu_read_unlock();3340 3341	prt_printf(out, "\t%px %c l=%u %s:", b, b->cached ? 'c' : 'b',3342		   b->level, bch2_btree_id_str(b->btree_id));3343	bch2_bpos_to_text(out, btree_node_pos(b));3344 3345	prt_printf(out, "\t locks %u:%u:%u held by pid %u",3346		   c.n[0], c.n[1], c.n[2], pid);3347}3348 3349void bch2_btree_trans_to_text(struct printbuf *out, struct btree_trans *trans)3350{3351	struct btree_bkey_cached_common *b;3352	static char lock_types[] = { 'r', 'i', 'w' };3353	struct task_struct *task = READ_ONCE(trans->locking_wait.task);3354	unsigned l, idx;3355 3356	/* before rcu_read_lock(): */3357	bch2_printbuf_make_room(out, 4096);3358 3359	if (!out->nr_tabstops) {3360		printbuf_tabstop_push(out, 16);3361		printbuf_tabstop_push(out, 32);3362	}3363 3364	prt_printf(out, "%i %s\n", task ? task->pid : 0, trans->fn);3365 3366	/* trans->paths is rcu protected vs. freeing */3367	rcu_read_lock();3368	out->atomic++;3369 3370	struct btree_path *paths = rcu_dereference(trans->paths);3371	if (!paths)3372		goto out;3373 3374	unsigned long *paths_allocated = trans_paths_allocated(paths);3375 3376	trans_for_each_path_idx_from(paths_allocated, *trans_paths_nr(paths), idx, 1) {3377		struct btree_path *path = paths + idx;3378		if (!path->nodes_locked)3379			continue;3380 3381		prt_printf(out, "  path %u %c l=%u %s:",3382		       idx,3383		       path->cached ? 'c' : 'b',3384		       path->level,3385		       bch2_btree_id_str(path->btree_id));3386		bch2_bpos_to_text(out, path->pos);3387		prt_newline(out);3388 3389		for (l = 0; l < BTREE_MAX_DEPTH; l++) {3390			if (btree_node_locked(path, l) &&3391			    !IS_ERR_OR_NULL(b = (void *) READ_ONCE(path->l[l].b))) {3392				prt_printf(out, "    %c l=%u ",3393					   lock_types[btree_node_locked_type(path, l)], l);3394				bch2_btree_bkey_cached_common_to_text(out, b);3395				prt_newline(out);3396			}3397		}3398	}3399 3400	b = READ_ONCE(trans->locking);3401	if (b) {3402		prt_printf(out, "  blocked for %lluus on\n",3403			   div_u64(local_clock() - trans->locking_wait.start_time, 1000));3404		prt_printf(out, "    %c", lock_types[trans->locking_wait.lock_want]);3405		bch2_btree_bkey_cached_common_to_text(out, b);3406		prt_newline(out);3407	}3408out:3409	--out->atomic;3410	rcu_read_unlock();3411}3412 3413void bch2_fs_btree_iter_exit(struct bch_fs *c)3414{3415	struct btree_transaction_stats *s;3416	struct btree_trans *trans;3417	int cpu;3418 3419	if (c->btree_trans_bufs)3420		for_each_possible_cpu(cpu) {3421			struct btree_trans *trans =3422				per_cpu_ptr(c->btree_trans_bufs, cpu)->trans;3423 3424			if (trans) {3425				seqmutex_lock(&c->btree_trans_lock);3426				list_del(&trans->list);3427				seqmutex_unlock(&c->btree_trans_lock);3428			}3429			kfree(trans);3430		}3431	free_percpu(c->btree_trans_bufs);3432 3433	trans = list_first_entry_or_null(&c->btree_trans_list, struct btree_trans, list);3434	if (trans)3435		panic("%s leaked btree_trans\n", trans->fn);3436 3437	for (s = c->btree_transaction_stats;3438	     s < c->btree_transaction_stats + ARRAY_SIZE(c->btree_transaction_stats);3439	     s++) {3440		kfree(s->max_paths_text);3441		bch2_time_stats_exit(&s->lock_hold_times);3442	}3443 3444	if (c->btree_trans_barrier_initialized) {3445		synchronize_srcu_expedited(&c->btree_trans_barrier);3446		cleanup_srcu_struct(&c->btree_trans_barrier);3447	}3448	mempool_exit(&c->btree_trans_mem_pool);3449	mempool_exit(&c->btree_trans_pool);3450}3451 3452void bch2_fs_btree_iter_init_early(struct bch_fs *c)3453{3454	struct btree_transaction_stats *s;3455 3456	for (s = c->btree_transaction_stats;3457	     s < c->btree_transaction_stats + ARRAY_SIZE(c->btree_transaction_stats);3458	     s++) {3459		bch2_time_stats_init(&s->duration);3460		bch2_time_stats_init(&s->lock_hold_times);3461		mutex_init(&s->lock);3462	}3463 3464	INIT_LIST_HEAD(&c->btree_trans_list);3465	seqmutex_init(&c->btree_trans_lock);3466}3467 3468int bch2_fs_btree_iter_init(struct bch_fs *c)3469{3470	int ret;3471 3472	c->btree_trans_bufs = alloc_percpu(struct btree_trans_buf);3473	if (!c->btree_trans_bufs)3474		return -ENOMEM;3475 3476	ret   = mempool_init_kmalloc_pool(&c->btree_trans_pool, 1,3477					  sizeof(struct btree_trans)) ?:3478		mempool_init_kmalloc_pool(&c->btree_trans_mem_pool, 1,3479					  BTREE_TRANS_MEM_MAX) ?:3480		init_srcu_struct(&c->btree_trans_barrier);3481	if (ret)3482		return ret;3483 3484	/*3485	 * static annotation (hackily done) for lock ordering of reclaim vs.3486	 * btree node locks:3487	 */3488#ifdef CONFIG_LOCKDEP3489	fs_reclaim_acquire(GFP_KERNEL);3490	struct btree_trans *trans = bch2_trans_get(c);3491	trans_set_locked(trans);3492	bch2_trans_put(trans);3493	fs_reclaim_release(GFP_KERNEL);3494#endif3495 3496	c->btree_trans_barrier_initialized = true;3497	return 0;3498 3499}3500