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1// SPDX-License-Identifier: GPL-2.0
2
3#include "bcachefs.h"
4#include "bkey_buf.h"
5#include "btree_cache.h"
6#include "btree_io.h"
7#include "btree_iter.h"
8#include "btree_locking.h"
9#include "debug.h"
10#include "errcode.h"
11#include "error.h"
12#include "journal.h"
13#include "trace.h"
14
15#include <linux/prefetch.h>
16#include <linux/sched/mm.h>
17
18const char * const bch2_btree_node_flags[] = {
19#define x(f) #f,
20 BTREE_FLAGS()
21#undef x
22 NULL
23};
24
25void bch2_recalc_btree_reserve(struct bch_fs *c)
26{
27 unsigned i, reserve = 16;
28
29 if (!c->btree_roots_known[0].b)
30 reserve += 8;
31
32 for (i = 0; i < btree_id_nr_alive(c); i++) {
33 struct btree_root *r = bch2_btree_id_root(c, i);
34
35 if (r->b)
36 reserve += min_t(unsigned, 1, r->b->c.level) * 8;
37 }
38
39 c->btree_cache.reserve = reserve;
40}
41
42static inline unsigned btree_cache_can_free(struct btree_cache *bc)
43{
44 return max_t(int, 0, bc->used - bc->reserve);
45}
46
47static void btree_node_to_freedlist(struct btree_cache *bc, struct btree *b)
48{
49 if (b->c.lock.readers)
50 list_move(&b->list, &bc->freed_pcpu);
51 else
52 list_move(&b->list, &bc->freed_nonpcpu);
53}
54
55static void btree_node_data_free(struct bch_fs *c, struct btree *b)
56{
57 struct btree_cache *bc = &c->btree_cache;
58
59 EBUG_ON(btree_node_write_in_flight(b));
60
61 clear_btree_node_just_written(b);
62
63 kvpfree(b->data, btree_buf_bytes(b));
64 b->data = NULL;
65#ifdef __KERNEL__
66 kvfree(b->aux_data);
67#else
68 munmap(b->aux_data, btree_aux_data_bytes(b));
69#endif
70 b->aux_data = NULL;
71
72 bc->used--;
73
74 btree_node_to_freedlist(bc, b);
75}
76
77static int bch2_btree_cache_cmp_fn(struct rhashtable_compare_arg *arg,
78 const void *obj)
79{
80 const struct btree *b = obj;
81 const u64 *v = arg->key;
82
83 return b->hash_val == *v ? 0 : 1;
84}
85
86static const struct rhashtable_params bch_btree_cache_params = {
87 .head_offset = offsetof(struct btree, hash),
88 .key_offset = offsetof(struct btree, hash_val),
89 .key_len = sizeof(u64),
90 .obj_cmpfn = bch2_btree_cache_cmp_fn,
91};
92
93static int btree_node_data_alloc(struct bch_fs *c, struct btree *b, gfp_t gfp)
94{
95 BUG_ON(b->data || b->aux_data);
96
97 b->data = kvpmalloc(btree_buf_bytes(b), gfp);
98 if (!b->data)
99 return -BCH_ERR_ENOMEM_btree_node_mem_alloc;
100#ifdef __KERNEL__
101 b->aux_data = kvmalloc(btree_aux_data_bytes(b), gfp);
102#else
103 b->aux_data = mmap(NULL, btree_aux_data_bytes(b),
104 PROT_READ|PROT_WRITE|PROT_EXEC,
105 MAP_PRIVATE|MAP_ANONYMOUS, 0, 0);
106 if (b->aux_data == MAP_FAILED)
107 b->aux_data = NULL;
108#endif
109 if (!b->aux_data) {
110 kvpfree(b->data, btree_buf_bytes(b));
111 b->data = NULL;
112 return -BCH_ERR_ENOMEM_btree_node_mem_alloc;
113 }
114
115 return 0;
116}
117
118static struct btree *__btree_node_mem_alloc(struct bch_fs *c, gfp_t gfp)
119{
120 struct btree *b;
121
122 b = kzalloc(sizeof(struct btree), gfp);
123 if (!b)
124 return NULL;
125
126 bkey_btree_ptr_init(&b->key);
127 INIT_LIST_HEAD(&b->list);
128 INIT_LIST_HEAD(&b->write_blocked);
129 b->byte_order = ilog2(c->opts.btree_node_size);
130 return b;
131}
132
133struct btree *__bch2_btree_node_mem_alloc(struct bch_fs *c)
134{
135 struct btree_cache *bc = &c->btree_cache;
136 struct btree *b;
137
138 b = __btree_node_mem_alloc(c, GFP_KERNEL);
139 if (!b)
140 return NULL;
141
142 if (btree_node_data_alloc(c, b, GFP_KERNEL)) {
143 kfree(b);
144 return NULL;
145 }
146
147 bch2_btree_lock_init(&b->c, 0);
148
149 bc->used++;
150 list_add(&b->list, &bc->freeable);
151 return b;
152}
153
154/* Btree in memory cache - hash table */
155
156void bch2_btree_node_hash_remove(struct btree_cache *bc, struct btree *b)
157{
158 int ret = rhashtable_remove_fast(&bc->table, &b->hash, bch_btree_cache_params);
159
160 BUG_ON(ret);
161
162 /* Cause future lookups for this node to fail: */
163 b->hash_val = 0;
164}
165
166int __bch2_btree_node_hash_insert(struct btree_cache *bc, struct btree *b)
167{
168 BUG_ON(b->hash_val);
169 b->hash_val = btree_ptr_hash_val(&b->key);
170
171 return rhashtable_lookup_insert_fast(&bc->table, &b->hash,
172 bch_btree_cache_params);
173}
174
175int bch2_btree_node_hash_insert(struct btree_cache *bc, struct btree *b,
176 unsigned level, enum btree_id id)
177{
178 int ret;
179
180 b->c.level = level;
181 b->c.btree_id = id;
182
183 mutex_lock(&bc->lock);
184 ret = __bch2_btree_node_hash_insert(bc, b);
185 if (!ret)
186 list_add_tail(&b->list, &bc->live);
187 mutex_unlock(&bc->lock);
188
189 return ret;
190}
191
192__flatten
193static inline struct btree *btree_cache_find(struct btree_cache *bc,
194 const struct bkey_i *k)
195{
196 u64 v = btree_ptr_hash_val(k);
197
198 return rhashtable_lookup_fast(&bc->table, &v, bch_btree_cache_params);
199}
200
201/*
202 * this version is for btree nodes that have already been freed (we're not
203 * reaping a real btree node)
204 */
205static int __btree_node_reclaim(struct bch_fs *c, struct btree *b, bool flush)
206{
207 struct btree_cache *bc = &c->btree_cache;
208 int ret = 0;
209
210 lockdep_assert_held(&bc->lock);
211wait_on_io:
212 if (b->flags & ((1U << BTREE_NODE_dirty)|
213 (1U << BTREE_NODE_read_in_flight)|
214 (1U << BTREE_NODE_write_in_flight))) {
215 if (!flush)
216 return -BCH_ERR_ENOMEM_btree_node_reclaim;
217
218 /* XXX: waiting on IO with btree cache lock held */
219 bch2_btree_node_wait_on_read(b);
220 bch2_btree_node_wait_on_write(b);
221 }
222
223 if (!six_trylock_intent(&b->c.lock))
224 return -BCH_ERR_ENOMEM_btree_node_reclaim;
225
226 if (!six_trylock_write(&b->c.lock))
227 goto out_unlock_intent;
228
229 /* recheck under lock */
230 if (b->flags & ((1U << BTREE_NODE_read_in_flight)|
231 (1U << BTREE_NODE_write_in_flight))) {
232 if (!flush)
233 goto out_unlock;
234 six_unlock_write(&b->c.lock);
235 six_unlock_intent(&b->c.lock);
236 goto wait_on_io;
237 }
238
239 if (btree_node_noevict(b) ||
240 btree_node_write_blocked(b) ||
241 btree_node_will_make_reachable(b))
242 goto out_unlock;
243
244 if (btree_node_dirty(b)) {
245 if (!flush)
246 goto out_unlock;
247 /*
248 * Using the underscore version because we don't want to compact
249 * bsets after the write, since this node is about to be evicted
250 * - unless btree verify mode is enabled, since it runs out of
251 * the post write cleanup:
252 */
253 if (bch2_verify_btree_ondisk)
254 bch2_btree_node_write(c, b, SIX_LOCK_intent,
255 BTREE_WRITE_cache_reclaim);
256 else
257 __bch2_btree_node_write(c, b,
258 BTREE_WRITE_cache_reclaim);
259
260 six_unlock_write(&b->c.lock);
261 six_unlock_intent(&b->c.lock);
262 goto wait_on_io;
263 }
264out:
265 if (b->hash_val && !ret)
266 trace_and_count(c, btree_cache_reap, c, b);
267 return ret;
268out_unlock:
269 six_unlock_write(&b->c.lock);
270out_unlock_intent:
271 six_unlock_intent(&b->c.lock);
272 ret = -BCH_ERR_ENOMEM_btree_node_reclaim;
273 goto out;
274}
275
276static int btree_node_reclaim(struct bch_fs *c, struct btree *b)
277{
278 return __btree_node_reclaim(c, b, false);
279}
280
281static int btree_node_write_and_reclaim(struct bch_fs *c, struct btree *b)
282{
283 return __btree_node_reclaim(c, b, true);
284}
285
286static unsigned long bch2_btree_cache_scan(struct shrinker *shrink,
287 struct shrink_control *sc)
288{
289 struct bch_fs *c = shrink->private_data;
290 struct btree_cache *bc = &c->btree_cache;
291 struct btree *b, *t;
292 unsigned long nr = sc->nr_to_scan;
293 unsigned long can_free = 0;
294 unsigned long freed = 0;
295 unsigned long touched = 0;
296 unsigned i, flags;
297 unsigned long ret = SHRINK_STOP;
298 bool trigger_writes = atomic_read(&bc->dirty) + nr >=
299 bc->used * 3 / 4;
300
301 if (bch2_btree_shrinker_disabled)
302 return SHRINK_STOP;
303
304 mutex_lock(&bc->lock);
305 flags = memalloc_nofs_save();
306
307 /*
308 * It's _really_ critical that we don't free too many btree nodes - we
309 * have to always leave ourselves a reserve. The reserve is how we
310 * guarantee that allocating memory for a new btree node can always
311 * succeed, so that inserting keys into the btree can always succeed and
312 * IO can always make forward progress:
313 */
314 can_free = btree_cache_can_free(bc);
315 nr = min_t(unsigned long, nr, can_free);
316
317 i = 0;
318 list_for_each_entry_safe(b, t, &bc->freeable, list) {
319 /*
320 * Leave a few nodes on the freeable list, so that a btree split
321 * won't have to hit the system allocator:
322 */
323 if (++i <= 3)
324 continue;
325
326 touched++;
327
328 if (touched >= nr)
329 goto out;
330
331 if (!btree_node_reclaim(c, b)) {
332 btree_node_data_free(c, b);
333 six_unlock_write(&b->c.lock);
334 six_unlock_intent(&b->c.lock);
335 freed++;
336 }
337 }
338restart:
339 list_for_each_entry_safe(b, t, &bc->live, list) {
340 touched++;
341
342 if (btree_node_accessed(b)) {
343 clear_btree_node_accessed(b);
344 } else if (!btree_node_reclaim(c, b)) {
345 freed++;
346 btree_node_data_free(c, b);
347
348 bch2_btree_node_hash_remove(bc, b);
349 six_unlock_write(&b->c.lock);
350 six_unlock_intent(&b->c.lock);
351
352 if (freed == nr)
353 goto out_rotate;
354 } else if (trigger_writes &&
355 btree_node_dirty(b) &&
356 !btree_node_will_make_reachable(b) &&
357 !btree_node_write_blocked(b) &&
358 six_trylock_read(&b->c.lock)) {
359 list_move(&bc->live, &b->list);
360 mutex_unlock(&bc->lock);
361 __bch2_btree_node_write(c, b, BTREE_WRITE_cache_reclaim);
362 six_unlock_read(&b->c.lock);
363 if (touched >= nr)
364 goto out_nounlock;
365 mutex_lock(&bc->lock);
366 goto restart;
367 }
368
369 if (touched >= nr)
370 break;
371 }
372out_rotate:
373 if (&t->list != &bc->live)
374 list_move_tail(&bc->live, &t->list);
375out:
376 mutex_unlock(&bc->lock);
377out_nounlock:
378 ret = freed;
379 memalloc_nofs_restore(flags);
380 trace_and_count(c, btree_cache_scan, sc->nr_to_scan, can_free, ret);
381 return ret;
382}
383
384static unsigned long bch2_btree_cache_count(struct shrinker *shrink,
385 struct shrink_control *sc)
386{
387 struct bch_fs *c = shrink->private_data;
388 struct btree_cache *bc = &c->btree_cache;
389
390 if (bch2_btree_shrinker_disabled)
391 return 0;
392
393 return btree_cache_can_free(bc);
394}
395
396void bch2_fs_btree_cache_exit(struct bch_fs *c)
397{
398 struct btree_cache *bc = &c->btree_cache;
399 struct btree *b;
400 unsigned i, flags;
401
402 shrinker_free(bc->shrink);
403
404 /* vfree() can allocate memory: */
405 flags = memalloc_nofs_save();
406 mutex_lock(&bc->lock);
407
408 if (c->verify_data)
409 list_move(&c->verify_data->list, &bc->live);
410
411 kvpfree(c->verify_ondisk, c->opts.btree_node_size);
412
413 for (i = 0; i < btree_id_nr_alive(c); i++) {
414 struct btree_root *r = bch2_btree_id_root(c, i);
415
416 if (r->b)
417 list_add(&r->b->list, &bc->live);
418 }
419
420 list_splice(&bc->freeable, &bc->live);
421
422 while (!list_empty(&bc->live)) {
423 b = list_first_entry(&bc->live, struct btree, list);
424
425 BUG_ON(btree_node_read_in_flight(b) ||
426 btree_node_write_in_flight(b));
427
428 btree_node_data_free(c, b);
429 }
430
431 BUG_ON(!bch2_journal_error(&c->journal) &&
432 atomic_read(&c->btree_cache.dirty));
433
434 list_splice(&bc->freed_pcpu, &bc->freed_nonpcpu);
435
436 while (!list_empty(&bc->freed_nonpcpu)) {
437 b = list_first_entry(&bc->freed_nonpcpu, struct btree, list);
438 list_del(&b->list);
439 six_lock_exit(&b->c.lock);
440 kfree(b);
441 }
442
443 mutex_unlock(&bc->lock);
444 memalloc_nofs_restore(flags);
445
446 if (bc->table_init_done)
447 rhashtable_destroy(&bc->table);
448}
449
450int bch2_fs_btree_cache_init(struct bch_fs *c)
451{
452 struct btree_cache *bc = &c->btree_cache;
453 struct shrinker *shrink;
454 unsigned i;
455 int ret = 0;
456
457 ret = rhashtable_init(&bc->table, &bch_btree_cache_params);
458 if (ret)
459 goto err;
460
461 bc->table_init_done = true;
462
463 bch2_recalc_btree_reserve(c);
464
465 for (i = 0; i < bc->reserve; i++)
466 if (!__bch2_btree_node_mem_alloc(c))
467 goto err;
468
469 list_splice_init(&bc->live, &bc->freeable);
470
471 mutex_init(&c->verify_lock);
472
473 shrink = shrinker_alloc(0, "%s-btree_cache", c->name);
474 if (!shrink)
475 goto err;
476 bc->shrink = shrink;
477 shrink->count_objects = bch2_btree_cache_count;
478 shrink->scan_objects = bch2_btree_cache_scan;
479 shrink->seeks = 4;
480 shrink->private_data = c;
481 shrinker_register(shrink);
482
483 return 0;
484err:
485 return -BCH_ERR_ENOMEM_fs_btree_cache_init;
486}
487
488void bch2_fs_btree_cache_init_early(struct btree_cache *bc)
489{
490 mutex_init(&bc->lock);
491 INIT_LIST_HEAD(&bc->live);
492 INIT_LIST_HEAD(&bc->freeable);
493 INIT_LIST_HEAD(&bc->freed_pcpu);
494 INIT_LIST_HEAD(&bc->freed_nonpcpu);
495}
496
497/*
498 * We can only have one thread cannibalizing other cached btree nodes at a time,
499 * or we'll deadlock. We use an open coded mutex to ensure that, which a
500 * cannibalize_bucket() will take. This means every time we unlock the root of
501 * the btree, we need to release this lock if we have it held.
502 */
503void bch2_btree_cache_cannibalize_unlock(struct btree_trans *trans)
504{
505 struct bch_fs *c = trans->c;
506 struct btree_cache *bc = &c->btree_cache;
507
508 if (bc->alloc_lock == current) {
509 trace_and_count(c, btree_cache_cannibalize_unlock, trans);
510 bc->alloc_lock = NULL;
511 closure_wake_up(&bc->alloc_wait);
512 }
513}
514
515int bch2_btree_cache_cannibalize_lock(struct btree_trans *trans, struct closure *cl)
516{
517 struct bch_fs *c = trans->c;
518 struct btree_cache *bc = &c->btree_cache;
519 struct task_struct *old;
520
521 old = cmpxchg(&bc->alloc_lock, NULL, current);
522 if (old == NULL || old == current)
523 goto success;
524
525 if (!cl) {
526 trace_and_count(c, btree_cache_cannibalize_lock_fail, trans);
527 return -BCH_ERR_ENOMEM_btree_cache_cannibalize_lock;
528 }
529
530 closure_wait(&bc->alloc_wait, cl);
531
532 /* Try again, after adding ourselves to waitlist */
533 old = cmpxchg(&bc->alloc_lock, NULL, current);
534 if (old == NULL || old == current) {
535 /* We raced */
536 closure_wake_up(&bc->alloc_wait);
537 goto success;
538 }
539
540 trace_and_count(c, btree_cache_cannibalize_lock_fail, trans);
541 return -BCH_ERR_btree_cache_cannibalize_lock_blocked;
542
543success:
544 trace_and_count(c, btree_cache_cannibalize_lock, trans);
545 return 0;
546}
547
548static struct btree *btree_node_cannibalize(struct bch_fs *c)
549{
550 struct btree_cache *bc = &c->btree_cache;
551 struct btree *b;
552
553 list_for_each_entry_reverse(b, &bc->live, list)
554 if (!btree_node_reclaim(c, b))
555 return b;
556
557 while (1) {
558 list_for_each_entry_reverse(b, &bc->live, list)
559 if (!btree_node_write_and_reclaim(c, b))
560 return b;
561
562 /*
563 * Rare case: all nodes were intent-locked.
564 * Just busy-wait.
565 */
566 WARN_ONCE(1, "btree cache cannibalize failed\n");
567 cond_resched();
568 }
569}
570
571struct btree *bch2_btree_node_mem_alloc(struct btree_trans *trans, bool pcpu_read_locks)
572{
573 struct bch_fs *c = trans->c;
574 struct btree_cache *bc = &c->btree_cache;
575 struct list_head *freed = pcpu_read_locks
576 ? &bc->freed_pcpu
577 : &bc->freed_nonpcpu;
578 struct btree *b, *b2;
579 u64 start_time = local_clock();
580 unsigned flags;
581
582 flags = memalloc_nofs_save();
583 mutex_lock(&bc->lock);
584
585 /*
586 * We never free struct btree itself, just the memory that holds the on
587 * disk node. Check the freed list before allocating a new one:
588 */
589 list_for_each_entry(b, freed, list)
590 if (!btree_node_reclaim(c, b)) {
591 list_del_init(&b->list);
592 goto got_node;
593 }
594
595 b = __btree_node_mem_alloc(c, GFP_NOWAIT|__GFP_NOWARN);
596 if (!b) {
597 mutex_unlock(&bc->lock);
598 bch2_trans_unlock(trans);
599 b = __btree_node_mem_alloc(c, GFP_KERNEL);
600 if (!b)
601 goto err;
602 mutex_lock(&bc->lock);
603 }
604
605 bch2_btree_lock_init(&b->c, pcpu_read_locks ? SIX_LOCK_INIT_PCPU : 0);
606
607 BUG_ON(!six_trylock_intent(&b->c.lock));
608 BUG_ON(!six_trylock_write(&b->c.lock));
609got_node:
610
611 /*
612 * btree_free() doesn't free memory; it sticks the node on the end of
613 * the list. Check if there's any freed nodes there:
614 */
615 list_for_each_entry(b2, &bc->freeable, list)
616 if (!btree_node_reclaim(c, b2)) {
617 swap(b->data, b2->data);
618 swap(b->aux_data, b2->aux_data);
619 btree_node_to_freedlist(bc, b2);
620 six_unlock_write(&b2->c.lock);
621 six_unlock_intent(&b2->c.lock);
622 goto got_mem;
623 }
624
625 mutex_unlock(&bc->lock);
626
627 if (btree_node_data_alloc(c, b, GFP_NOWAIT|__GFP_NOWARN)) {
628 bch2_trans_unlock(trans);
629 if (btree_node_data_alloc(c, b, GFP_KERNEL|__GFP_NOWARN))
630 goto err;
631 }
632
633 mutex_lock(&bc->lock);
634 bc->used++;
635got_mem:
636 mutex_unlock(&bc->lock);
637
638 BUG_ON(btree_node_hashed(b));
639 BUG_ON(btree_node_dirty(b));
640 BUG_ON(btree_node_write_in_flight(b));
641out:
642 b->flags = 0;
643 b->written = 0;
644 b->nsets = 0;
645 b->sib_u64s[0] = 0;
646 b->sib_u64s[1] = 0;
647 b->whiteout_u64s = 0;
648 bch2_btree_keys_init(b);
649 set_btree_node_accessed(b);
650
651 bch2_time_stats_update(&c->times[BCH_TIME_btree_node_mem_alloc],
652 start_time);
653
654 memalloc_nofs_restore(flags);
655 return b;
656err:
657 mutex_lock(&bc->lock);
658
659 /* Try to cannibalize another cached btree node: */
660 if (bc->alloc_lock == current) {
661 b2 = btree_node_cannibalize(c);
662 clear_btree_node_just_written(b2);
663 bch2_btree_node_hash_remove(bc, b2);
664
665 if (b) {
666 swap(b->data, b2->data);
667 swap(b->aux_data, b2->aux_data);
668 btree_node_to_freedlist(bc, b2);
669 six_unlock_write(&b2->c.lock);
670 six_unlock_intent(&b2->c.lock);
671 } else {
672 b = b2;
673 list_del_init(&b->list);
674 }
675
676 mutex_unlock(&bc->lock);
677
678 trace_and_count(c, btree_cache_cannibalize, trans);
679 goto out;
680 }
681
682 mutex_unlock(&bc->lock);
683 memalloc_nofs_restore(flags);
684 return ERR_PTR(-BCH_ERR_ENOMEM_btree_node_mem_alloc);
685}
686
687/* Slowpath, don't want it inlined into btree_iter_traverse() */
688static noinline struct btree *bch2_btree_node_fill(struct btree_trans *trans,
689 struct btree_path *path,
690 const struct bkey_i *k,
691 enum btree_id btree_id,
692 unsigned level,
693 enum six_lock_type lock_type,
694 bool sync)
695{
696 struct bch_fs *c = trans->c;
697 struct btree_cache *bc = &c->btree_cache;
698 struct btree *b;
699 u32 seq;
700
701 BUG_ON(level + 1 >= BTREE_MAX_DEPTH);
702 /*
703 * Parent node must be locked, else we could read in a btree node that's
704 * been freed:
705 */
706 if (path && !bch2_btree_node_relock(trans, path, level + 1)) {
707 trace_and_count(c, trans_restart_relock_parent_for_fill, trans, _THIS_IP_, path);
708 return ERR_PTR(btree_trans_restart(trans, BCH_ERR_transaction_restart_fill_relock));
709 }
710
711 b = bch2_btree_node_mem_alloc(trans, level != 0);
712
713 if (bch2_err_matches(PTR_ERR_OR_ZERO(b), ENOMEM)) {
714 trans->memory_allocation_failure = true;
715 trace_and_count(c, trans_restart_memory_allocation_failure, trans, _THIS_IP_, path);
716 return ERR_PTR(btree_trans_restart(trans, BCH_ERR_transaction_restart_fill_mem_alloc_fail));
717 }
718
719 if (IS_ERR(b))
720 return b;
721
722 bkey_copy(&b->key, k);
723 if (bch2_btree_node_hash_insert(bc, b, level, btree_id)) {
724 /* raced with another fill: */
725
726 /* mark as unhashed... */
727 b->hash_val = 0;
728
729 mutex_lock(&bc->lock);
730 list_add(&b->list, &bc->freeable);
731 mutex_unlock(&bc->lock);
732
733 six_unlock_write(&b->c.lock);
734 six_unlock_intent(&b->c.lock);
735 return NULL;
736 }
737
738 set_btree_node_read_in_flight(b);
739
740 six_unlock_write(&b->c.lock);
741 seq = six_lock_seq(&b->c.lock);
742 six_unlock_intent(&b->c.lock);
743
744 /* Unlock before doing IO: */
745 if (path && sync)
746 bch2_trans_unlock_noassert(trans);
747
748 bch2_btree_node_read(trans, b, sync);
749
750 if (!sync)
751 return NULL;
752
753 if (path) {
754 int ret = bch2_trans_relock(trans) ?:
755 bch2_btree_path_relock_intent(trans, path);
756 if (ret) {
757 BUG_ON(!trans->restarted);
758 return ERR_PTR(ret);
759 }
760 }
761
762 if (!six_relock_type(&b->c.lock, lock_type, seq)) {
763 if (path)
764 trace_and_count(c, trans_restart_relock_after_fill, trans, _THIS_IP_, path);
765 return ERR_PTR(btree_trans_restart(trans, BCH_ERR_transaction_restart_relock_after_fill));
766 }
767
768 return b;
769}
770
771static noinline void btree_bad_header(struct bch_fs *c, struct btree *b)
772{
773 struct printbuf buf = PRINTBUF;
774
775 if (c->curr_recovery_pass <= BCH_RECOVERY_PASS_check_allocations)
776 return;
777
778 prt_printf(&buf,
779 "btree node header doesn't match ptr\n"
780 "btree %s level %u\n"
781 "ptr: ",
782 bch2_btree_id_str(b->c.btree_id), b->c.level);
783 bch2_bkey_val_to_text(&buf, c, bkey_i_to_s_c(&b->key));
784
785 prt_printf(&buf, "\nheader: btree %s level %llu\n"
786 "min ",
787 bch2_btree_id_str(BTREE_NODE_ID(b->data)),
788 BTREE_NODE_LEVEL(b->data));
789 bch2_bpos_to_text(&buf, b->data->min_key);
790
791 prt_printf(&buf, "\nmax ");
792 bch2_bpos_to_text(&buf, b->data->max_key);
793
794 bch2_fs_inconsistent(c, "%s", buf.buf);
795 printbuf_exit(&buf);
796}
797
798static inline void btree_check_header(struct bch_fs *c, struct btree *b)
799{
800 if (b->c.btree_id != BTREE_NODE_ID(b->data) ||
801 b->c.level != BTREE_NODE_LEVEL(b->data) ||
802 !bpos_eq(b->data->max_key, b->key.k.p) ||
803 (b->key.k.type == KEY_TYPE_btree_ptr_v2 &&
804 !bpos_eq(b->data->min_key,
805 bkey_i_to_btree_ptr_v2(&b->key)->v.min_key)))
806 btree_bad_header(c, b);
807}
808
809static struct btree *__bch2_btree_node_get(struct btree_trans *trans, struct btree_path *path,
810 const struct bkey_i *k, unsigned level,
811 enum six_lock_type lock_type,
812 unsigned long trace_ip)
813{
814 struct bch_fs *c = trans->c;
815 struct btree_cache *bc = &c->btree_cache;
816 struct btree *b;
817 struct bset_tree *t;
818 bool need_relock = false;
819 int ret;
820
821 EBUG_ON(level >= BTREE_MAX_DEPTH);
822retry:
823 b = btree_cache_find(bc, k);
824 if (unlikely(!b)) {
825 /*
826 * We must have the parent locked to call bch2_btree_node_fill(),
827 * else we could read in a btree node from disk that's been
828 * freed:
829 */
830 b = bch2_btree_node_fill(trans, path, k, path->btree_id,
831 level, lock_type, true);
832 need_relock = true;
833
834 /* We raced and found the btree node in the cache */
835 if (!b)
836 goto retry;
837
838 if (IS_ERR(b))
839 return b;
840 } else {
841 if (btree_node_read_locked(path, level + 1))
842 btree_node_unlock(trans, path, level + 1);
843
844 ret = btree_node_lock(trans, path, &b->c, level, lock_type, trace_ip);
845 if (bch2_err_matches(ret, BCH_ERR_transaction_restart))
846 return ERR_PTR(ret);
847
848 BUG_ON(ret);
849
850 if (unlikely(b->hash_val != btree_ptr_hash_val(k) ||
851 b->c.level != level ||
852 race_fault())) {
853 six_unlock_type(&b->c.lock, lock_type);
854 if (bch2_btree_node_relock(trans, path, level + 1))
855 goto retry;
856
857 trace_and_count(c, trans_restart_btree_node_reused, trans, trace_ip, path);
858 return ERR_PTR(btree_trans_restart(trans, BCH_ERR_transaction_restart_lock_node_reused));
859 }
860
861 /* avoid atomic set bit if it's not needed: */
862 if (!btree_node_accessed(b))
863 set_btree_node_accessed(b);
864 }
865
866 if (unlikely(btree_node_read_in_flight(b))) {
867 u32 seq = six_lock_seq(&b->c.lock);
868
869 six_unlock_type(&b->c.lock, lock_type);
870 bch2_trans_unlock(trans);
871 need_relock = true;
872
873 bch2_btree_node_wait_on_read(b);
874
875 /*
876 * should_be_locked is not set on this path yet, so we need to
877 * relock it specifically:
878 */
879 if (!six_relock_type(&b->c.lock, lock_type, seq))
880 goto retry;
881 }
882
883 if (unlikely(need_relock)) {
884 ret = bch2_trans_relock(trans) ?:
885 bch2_btree_path_relock_intent(trans, path);
886 if (ret) {
887 six_unlock_type(&b->c.lock, lock_type);
888 return ERR_PTR(ret);
889 }
890 }
891
892 prefetch(b->aux_data);
893
894 for_each_bset(b, t) {
895 void *p = (u64 *) b->aux_data + t->aux_data_offset;
896
897 prefetch(p + L1_CACHE_BYTES * 0);
898 prefetch(p + L1_CACHE_BYTES * 1);
899 prefetch(p + L1_CACHE_BYTES * 2);
900 }
901
902 if (unlikely(btree_node_read_error(b))) {
903 six_unlock_type(&b->c.lock, lock_type);
904 return ERR_PTR(-EIO);
905 }
906
907 EBUG_ON(b->c.btree_id != path->btree_id);
908 EBUG_ON(BTREE_NODE_LEVEL(b->data) != level);
909 btree_check_header(c, b);
910
911 return b;
912}
913
914/**
915 * bch2_btree_node_get - find a btree node in the cache and lock it, reading it
916 * in from disk if necessary.
917 *
918 * @trans: btree transaction object
919 * @path: btree_path being traversed
920 * @k: pointer to btree node (generally KEY_TYPE_btree_ptr_v2)
921 * @level: level of btree node being looked up (0 == leaf node)
922 * @lock_type: SIX_LOCK_read or SIX_LOCK_intent
923 * @trace_ip: ip of caller of btree iterator code (i.e. caller of bch2_btree_iter_peek())
924 *
925 * The btree node will have either a read or a write lock held, depending on
926 * the @write parameter.
927 *
928 * Returns: btree node or ERR_PTR()
929 */
930struct btree *bch2_btree_node_get(struct btree_trans *trans, struct btree_path *path,
931 const struct bkey_i *k, unsigned level,
932 enum six_lock_type lock_type,
933 unsigned long trace_ip)
934{
935 struct bch_fs *c = trans->c;
936 struct btree *b;
937 struct bset_tree *t;
938 int ret;
939
940 EBUG_ON(level >= BTREE_MAX_DEPTH);
941
942 b = btree_node_mem_ptr(k);
943
944 /*
945 * Check b->hash_val _before_ calling btree_node_lock() - this might not
946 * be the node we want anymore, and trying to lock the wrong node could
947 * cause an unneccessary transaction restart:
948 */
949 if (unlikely(!c->opts.btree_node_mem_ptr_optimization ||
950 !b ||
951 b->hash_val != btree_ptr_hash_val(k)))
952 return __bch2_btree_node_get(trans, path, k, level, lock_type, trace_ip);
953
954 if (btree_node_read_locked(path, level + 1))
955 btree_node_unlock(trans, path, level + 1);
956
957 ret = btree_node_lock(trans, path, &b->c, level, lock_type, trace_ip);
958 if (bch2_err_matches(ret, BCH_ERR_transaction_restart))
959 return ERR_PTR(ret);
960
961 BUG_ON(ret);
962
963 if (unlikely(b->hash_val != btree_ptr_hash_val(k) ||
964 b->c.level != level ||
965 race_fault())) {
966 six_unlock_type(&b->c.lock, lock_type);
967 if (bch2_btree_node_relock(trans, path, level + 1))
968 return __bch2_btree_node_get(trans, path, k, level, lock_type, trace_ip);
969
970 trace_and_count(c, trans_restart_btree_node_reused, trans, trace_ip, path);
971 return ERR_PTR(btree_trans_restart(trans, BCH_ERR_transaction_restart_lock_node_reused));
972 }
973
974 if (unlikely(btree_node_read_in_flight(b))) {
975 six_unlock_type(&b->c.lock, lock_type);
976 return __bch2_btree_node_get(trans, path, k, level, lock_type, trace_ip);
977 }
978
979 prefetch(b->aux_data);
980
981 for_each_bset(b, t) {
982 void *p = (u64 *) b->aux_data + t->aux_data_offset;
983
984 prefetch(p + L1_CACHE_BYTES * 0);
985 prefetch(p + L1_CACHE_BYTES * 1);
986 prefetch(p + L1_CACHE_BYTES * 2);
987 }
988
989 /* avoid atomic set bit if it's not needed: */
990 if (!btree_node_accessed(b))
991 set_btree_node_accessed(b);
992
993 if (unlikely(btree_node_read_error(b))) {
994 six_unlock_type(&b->c.lock, lock_type);
995 return ERR_PTR(-EIO);
996 }
997
998 EBUG_ON(b->c.btree_id != path->btree_id);
999 EBUG_ON(BTREE_NODE_LEVEL(b->data) != level);
1000 btree_check_header(c, b);
1001
1002 return b;
1003}
1004
1005struct btree *bch2_btree_node_get_noiter(struct btree_trans *trans,
1006 const struct bkey_i *k,
1007 enum btree_id btree_id,
1008 unsigned level,
1009 bool nofill)
1010{
1011 struct bch_fs *c = trans->c;
1012 struct btree_cache *bc = &c->btree_cache;
1013 struct btree *b;
1014 struct bset_tree *t;
1015 int ret;
1016
1017 EBUG_ON(level >= BTREE_MAX_DEPTH);
1018
1019 if (c->opts.btree_node_mem_ptr_optimization) {
1020 b = btree_node_mem_ptr(k);
1021 if (b)
1022 goto lock_node;
1023 }
1024retry:
1025 b = btree_cache_find(bc, k);
1026 if (unlikely(!b)) {
1027 if (nofill)
1028 goto out;
1029
1030 b = bch2_btree_node_fill(trans, NULL, k, btree_id,
1031 level, SIX_LOCK_read, true);
1032
1033 /* We raced and found the btree node in the cache */
1034 if (!b)
1035 goto retry;
1036
1037 if (IS_ERR(b) &&
1038 !bch2_btree_cache_cannibalize_lock(trans, NULL))
1039 goto retry;
1040
1041 if (IS_ERR(b))
1042 goto out;
1043 } else {
1044lock_node:
1045 ret = btree_node_lock_nopath(trans, &b->c, SIX_LOCK_read, _THIS_IP_);
1046 if (bch2_err_matches(ret, BCH_ERR_transaction_restart))
1047 return ERR_PTR(ret);
1048
1049 BUG_ON(ret);
1050
1051 if (unlikely(b->hash_val != btree_ptr_hash_val(k) ||
1052 b->c.btree_id != btree_id ||
1053 b->c.level != level)) {
1054 six_unlock_read(&b->c.lock);
1055 goto retry;
1056 }
1057 }
1058
1059 /* XXX: waiting on IO with btree locks held: */
1060 __bch2_btree_node_wait_on_read(b);
1061
1062 prefetch(b->aux_data);
1063
1064 for_each_bset(b, t) {
1065 void *p = (u64 *) b->aux_data + t->aux_data_offset;
1066
1067 prefetch(p + L1_CACHE_BYTES * 0);
1068 prefetch(p + L1_CACHE_BYTES * 1);
1069 prefetch(p + L1_CACHE_BYTES * 2);
1070 }
1071
1072 /* avoid atomic set bit if it's not needed: */
1073 if (!btree_node_accessed(b))
1074 set_btree_node_accessed(b);
1075
1076 if (unlikely(btree_node_read_error(b))) {
1077 six_unlock_read(&b->c.lock);
1078 b = ERR_PTR(-EIO);
1079 goto out;
1080 }
1081
1082 EBUG_ON(b->c.btree_id != btree_id);
1083 EBUG_ON(BTREE_NODE_LEVEL(b->data) != level);
1084 btree_check_header(c, b);
1085out:
1086 bch2_btree_cache_cannibalize_unlock(trans);
1087 return b;
1088}
1089
1090int bch2_btree_node_prefetch(struct btree_trans *trans,
1091 struct btree_path *path,
1092 const struct bkey_i *k,
1093 enum btree_id btree_id, unsigned level)
1094{
1095 struct bch_fs *c = trans->c;
1096 struct btree_cache *bc = &c->btree_cache;
1097 struct btree *b;
1098
1099 BUG_ON(trans && !btree_node_locked(path, level + 1));
1100 BUG_ON(level >= BTREE_MAX_DEPTH);
1101
1102 b = btree_cache_find(bc, k);
1103 if (b)
1104 return 0;
1105
1106 b = bch2_btree_node_fill(trans, path, k, btree_id,
1107 level, SIX_LOCK_read, false);
1108 return PTR_ERR_OR_ZERO(b);
1109}
1110
1111void bch2_btree_node_evict(struct btree_trans *trans, const struct bkey_i *k)
1112{
1113 struct bch_fs *c = trans->c;
1114 struct btree_cache *bc = &c->btree_cache;
1115 struct btree *b;
1116
1117 b = btree_cache_find(bc, k);
1118 if (!b)
1119 return;
1120wait_on_io:
1121 /* not allowed to wait on io with btree locks held: */
1122
1123 /* XXX we're called from btree_gc which will be holding other btree
1124 * nodes locked
1125 */
1126 __bch2_btree_node_wait_on_read(b);
1127 __bch2_btree_node_wait_on_write(b);
1128
1129 btree_node_lock_nopath_nofail(trans, &b->c, SIX_LOCK_intent);
1130 btree_node_lock_nopath_nofail(trans, &b->c, SIX_LOCK_write);
1131
1132 if (btree_node_dirty(b)) {
1133 __bch2_btree_node_write(c, b, BTREE_WRITE_cache_reclaim);
1134 six_unlock_write(&b->c.lock);
1135 six_unlock_intent(&b->c.lock);
1136 goto wait_on_io;
1137 }
1138
1139 BUG_ON(btree_node_dirty(b));
1140
1141 mutex_lock(&bc->lock);
1142 btree_node_data_free(c, b);
1143 bch2_btree_node_hash_remove(bc, b);
1144 mutex_unlock(&bc->lock);
1145
1146 six_unlock_write(&b->c.lock);
1147 six_unlock_intent(&b->c.lock);
1148}
1149
1150const char *bch2_btree_id_str(enum btree_id btree)
1151{
1152 return btree < BTREE_ID_NR ? __bch2_btree_ids[btree] : "(unknown)";
1153}
1154
1155void bch2_btree_pos_to_text(struct printbuf *out, struct bch_fs *c, const struct btree *b)
1156{
1157 prt_printf(out, "%s level %u/%u\n ",
1158 bch2_btree_id_str(b->c.btree_id),
1159 b->c.level,
1160 bch2_btree_id_root(c, b->c.btree_id)->level);
1161 bch2_bkey_val_to_text(out, c, bkey_i_to_s_c(&b->key));
1162}
1163
1164void bch2_btree_node_to_text(struct printbuf *out, struct bch_fs *c, const struct btree *b)
1165{
1166 struct bset_stats stats;
1167
1168 memset(&stats, 0, sizeof(stats));
1169
1170 bch2_btree_keys_stats(b, &stats);
1171
1172 prt_printf(out, "l %u ", b->c.level);
1173 bch2_bpos_to_text(out, b->data->min_key);
1174 prt_printf(out, " - ");
1175 bch2_bpos_to_text(out, b->data->max_key);
1176 prt_printf(out, ":\n"
1177 " ptrs: ");
1178 bch2_val_to_text(out, c, bkey_i_to_s_c(&b->key));
1179 prt_newline(out);
1180
1181 prt_printf(out,
1182 " format: ");
1183 bch2_bkey_format_to_text(out, &b->format);
1184
1185 prt_printf(out,
1186 " unpack fn len: %u\n"
1187 " bytes used %zu/%zu (%zu%% full)\n"
1188 " sib u64s: %u, %u (merge threshold %u)\n"
1189 " nr packed keys %u\n"
1190 " nr unpacked keys %u\n"
1191 " floats %zu\n"
1192 " failed unpacked %zu\n",
1193 b->unpack_fn_len,
1194 b->nr.live_u64s * sizeof(u64),
1195 btree_buf_bytes(b) - sizeof(struct btree_node),
1196 b->nr.live_u64s * 100 / btree_max_u64s(c),
1197 b->sib_u64s[0],
1198 b->sib_u64s[1],
1199 c->btree_foreground_merge_threshold,
1200 b->nr.packed_keys,
1201 b->nr.unpacked_keys,
1202 stats.floats,
1203 stats.failed);
1204}
1205
1206void bch2_btree_cache_to_text(struct printbuf *out, const struct bch_fs *c)
1207{
1208 prt_printf(out, "nr nodes:\t\t%u\n", c->btree_cache.used);
1209 prt_printf(out, "nr dirty:\t\t%u\n", atomic_read(&c->btree_cache.dirty));
1210 prt_printf(out, "cannibalize lock:\t%p\n", c->btree_cache.alloc_lock);
1211}