1// SPDX-License-Identifier: GPL-2.0
2
3#include "bcachefs.h"
4#include "btree_cache.h"
5#include "btree_iter.h"
6#include "btree_key_cache.h"
7#include "btree_locking.h"
8#include "btree_update.h"
9#include "errcode.h"
10#include "error.h"
11#include "journal.h"
12#include "journal_reclaim.h"
13#include "trace.h"
14
15#include <linux/sched/mm.h>
16
17static inline bool btree_uses_pcpu_readers(enum btree_id id)
18{
19 return id == BTREE_ID_subvolumes;
20}
21
22static struct kmem_cache *bch2_key_cache;
23
24static int bch2_btree_key_cache_cmp_fn(struct rhashtable_compare_arg *arg,
25 const void *obj)
26{
27 const struct bkey_cached *ck = obj;
28 const struct bkey_cached_key *key = arg->key;
29
30 return ck->key.btree_id != key->btree_id ||
31 !bpos_eq(l: ck->key.pos, r: key->pos);
32}
33
34static const struct rhashtable_params bch2_btree_key_cache_params = {
35 .head_offset = offsetof(struct bkey_cached, hash),
36 .key_offset = offsetof(struct bkey_cached, key),
37 .key_len = sizeof(struct bkey_cached_key),
38 .obj_cmpfn = bch2_btree_key_cache_cmp_fn,
39};
40
41__flatten
42inline struct bkey_cached *
43bch2_btree_key_cache_find(struct bch_fs *c, enum btree_id btree_id, struct bpos pos)
44{
45 struct bkey_cached_key key = {
46 .btree_id = btree_id,
47 .pos = pos,
48 };
49
50 return rhashtable_lookup_fast(ht: &c->btree_key_cache.table, key: &key,
51 params: bch2_btree_key_cache_params);
52}
53
54static bool bkey_cached_lock_for_evict(struct bkey_cached *ck)
55{
56 if (!six_trylock_intent(lock: &ck->c.lock))
57 return false;
58
59 if (test_bit(BKEY_CACHED_DIRTY, &ck->flags)) {
60 six_unlock_intent(lock: &ck->c.lock);
61 return false;
62 }
63
64 if (!six_trylock_write(lock: &ck->c.lock)) {
65 six_unlock_intent(lock: &ck->c.lock);
66 return false;
67 }
68
69 return true;
70}
71
72static void bkey_cached_evict(struct btree_key_cache *c,
73 struct bkey_cached *ck)
74{
75 BUG_ON(rhashtable_remove_fast(&c->table, &ck->hash,
76 bch2_btree_key_cache_params));
77 memset(&ck->key, ~0, sizeof(ck->key));
78
79 atomic_long_dec(v: &c->nr_keys);
80}
81
82static void bkey_cached_free(struct btree_key_cache *bc,
83 struct bkey_cached *ck)
84{
85 struct bch_fs *c = container_of(bc, struct bch_fs, btree_key_cache);
86
87 BUG_ON(test_bit(BKEY_CACHED_DIRTY, &ck->flags));
88
89 ck->btree_trans_barrier_seq =
90 start_poll_synchronize_srcu(ssp: &c->btree_trans_barrier);
91
92 if (ck->c.lock.readers) {
93 list_move_tail(list: &ck->list, head: &bc->freed_pcpu);
94 bc->nr_freed_pcpu++;
95 } else {
96 list_move_tail(list: &ck->list, head: &bc->freed_nonpcpu);
97 bc->nr_freed_nonpcpu++;
98 }
99 atomic_long_inc(v: &bc->nr_freed);
100
101 kfree(objp: ck->k);
102 ck->k = NULL;
103 ck->u64s = 0;
104
105 six_unlock_write(lock: &ck->c.lock);
106 six_unlock_intent(lock: &ck->c.lock);
107}
108
109#ifdef __KERNEL__
110static void __bkey_cached_move_to_freelist_ordered(struct btree_key_cache *bc,
111 struct bkey_cached *ck)
112{
113 struct bkey_cached *pos;
114
115 bc->nr_freed_nonpcpu++;
116
117 list_for_each_entry_reverse(pos, &bc->freed_nonpcpu, list) {
118 if (ULONG_CMP_GE(ck->btree_trans_barrier_seq,
119 pos->btree_trans_barrier_seq)) {
120 list_move(list: &ck->list, head: &pos->list);
121 return;
122 }
123 }
124
125 list_move(list: &ck->list, head: &bc->freed_nonpcpu);
126}
127#endif
128
129static void bkey_cached_move_to_freelist(struct btree_key_cache *bc,
130 struct bkey_cached *ck)
131{
132 BUG_ON(test_bit(BKEY_CACHED_DIRTY, &ck->flags));
133
134 if (!ck->c.lock.readers) {
135#ifdef __KERNEL__
136 struct btree_key_cache_freelist *f;
137 bool freed = false;
138
139 preempt_disable();
140 f = this_cpu_ptr(bc->pcpu_freed);
141
142 if (f->nr < ARRAY_SIZE(f->objs)) {
143 f->objs[f->nr++] = ck;
144 freed = true;
145 }
146 preempt_enable();
147
148 if (!freed) {
149 mutex_lock(&bc->lock);
150 preempt_disable();
151 f = this_cpu_ptr(bc->pcpu_freed);
152
153 while (f->nr > ARRAY_SIZE(f->objs) / 2) {
154 struct bkey_cached *ck2 = f->objs[--f->nr];
155
156 __bkey_cached_move_to_freelist_ordered(bc, ck: ck2);
157 }
158 preempt_enable();
159
160 __bkey_cached_move_to_freelist_ordered(bc, ck);
161 mutex_unlock(lock: &bc->lock);
162 }
163#else
164 mutex_lock(&bc->lock);
165 list_move_tail(&ck->list, &bc->freed_nonpcpu);
166 bc->nr_freed_nonpcpu++;
167 mutex_unlock(&bc->lock);
168#endif
169 } else {
170 mutex_lock(&bc->lock);
171 list_move_tail(list: &ck->list, head: &bc->freed_pcpu);
172 bc->nr_freed_pcpu++;
173 mutex_unlock(lock: &bc->lock);
174 }
175}
176
177static void bkey_cached_free_fast(struct btree_key_cache *bc,
178 struct bkey_cached *ck)
179{
180 struct bch_fs *c = container_of(bc, struct bch_fs, btree_key_cache);
181
182 ck->btree_trans_barrier_seq =
183 start_poll_synchronize_srcu(ssp: &c->btree_trans_barrier);
184
185 list_del_init(entry: &ck->list);
186 atomic_long_inc(v: &bc->nr_freed);
187
188 kfree(objp: ck->k);
189 ck->k = NULL;
190 ck->u64s = 0;
191
192 bkey_cached_move_to_freelist(bc, ck);
193
194 six_unlock_write(lock: &ck->c.lock);
195 six_unlock_intent(lock: &ck->c.lock);
196}
197
198static struct bkey_cached *
199bkey_cached_alloc(struct btree_trans *trans, struct btree_path *path,
200 bool *was_new)
201{
202 struct bch_fs *c = trans->c;
203 struct btree_key_cache *bc = &c->btree_key_cache;
204 struct bkey_cached *ck = NULL;
205 bool pcpu_readers = btree_uses_pcpu_readers(id: path->btree_id);
206 int ret;
207
208 if (!pcpu_readers) {
209#ifdef __KERNEL__
210 struct btree_key_cache_freelist *f;
211
212 preempt_disable();
213 f = this_cpu_ptr(bc->pcpu_freed);
214 if (f->nr)
215 ck = f->objs[--f->nr];
216 preempt_enable();
217
218 if (!ck) {
219 mutex_lock(&bc->lock);
220 preempt_disable();
221 f = this_cpu_ptr(bc->pcpu_freed);
222
223 while (!list_empty(head: &bc->freed_nonpcpu) &&
224 f->nr < ARRAY_SIZE(f->objs) / 2) {
225 ck = list_last_entry(&bc->freed_nonpcpu, struct bkey_cached, list);
226 list_del_init(entry: &ck->list);
227 bc->nr_freed_nonpcpu--;
228 f->objs[f->nr++] = ck;
229 }
230
231 ck = f->nr ? f->objs[--f->nr] : NULL;
232 preempt_enable();
233 mutex_unlock(lock: &bc->lock);
234 }
235#else
236 mutex_lock(&bc->lock);
237 if (!list_empty(&bc->freed_nonpcpu)) {
238 ck = list_last_entry(&bc->freed_nonpcpu, struct bkey_cached, list);
239 list_del_init(&ck->list);
240 bc->nr_freed_nonpcpu--;
241 }
242 mutex_unlock(&bc->lock);
243#endif
244 } else {
245 mutex_lock(&bc->lock);
246 if (!list_empty(head: &bc->freed_pcpu)) {
247 ck = list_last_entry(&bc->freed_pcpu, struct bkey_cached, list);
248 list_del_init(entry: &ck->list);
249 bc->nr_freed_pcpu--;
250 }
251 mutex_unlock(lock: &bc->lock);
252 }
253
254 if (ck) {
255 ret = btree_node_lock_nopath(trans, b: &ck->c, type: SIX_LOCK_intent, _THIS_IP_);
256 if (unlikely(ret)) {
257 bkey_cached_move_to_freelist(bc, ck);
258 return ERR_PTR(error: ret);
259 }
260
261 path->l[0].b = (void *) ck;
262 path->l[0].lock_seq = six_lock_seq(lock: &ck->c.lock);
263 mark_btree_node_locked(trans, path, level: 0, type: BTREE_NODE_INTENT_LOCKED);
264
265 ret = bch2_btree_node_lock_write(trans, path, b: &ck->c);
266 if (unlikely(ret)) {
267 btree_node_unlock(trans, path, level: 0);
268 bkey_cached_move_to_freelist(bc, ck);
269 return ERR_PTR(error: ret);
270 }
271
272 return ck;
273 }
274
275 ck = allocate_dropping_locks(trans, ret,
276 kmem_cache_zalloc(bch2_key_cache, _gfp));
277 if (ret) {
278 kmem_cache_free(s: bch2_key_cache, objp: ck);
279 return ERR_PTR(error: ret);
280 }
281
282 if (!ck)
283 return NULL;
284
285 INIT_LIST_HEAD(list: &ck->list);
286 bch2_btree_lock_init(&ck->c, pcpu_readers ? SIX_LOCK_INIT_PCPU : 0);
287
288 ck->c.cached = true;
289 BUG_ON(!six_trylock_intent(&ck->c.lock));
290 BUG_ON(!six_trylock_write(&ck->c.lock));
291 *was_new = true;
292 return ck;
293}
294
295static struct bkey_cached *
296bkey_cached_reuse(struct btree_key_cache *c)
297{
298 struct bucket_table *tbl;
299 struct rhash_head *pos;
300 struct bkey_cached *ck;
301 unsigned i;
302
303 mutex_lock(&c->lock);
304 rcu_read_lock();
305 tbl = rht_dereference_rcu(c->table.tbl, &c->table);
306 for (i = 0; i < tbl->size; i++)
307 rht_for_each_entry_rcu(ck, pos, tbl, i, hash) {
308 if (!test_bit(BKEY_CACHED_DIRTY, &ck->flags) &&
309 bkey_cached_lock_for_evict(ck)) {
310 bkey_cached_evict(c, ck);
311 goto out;
312 }
313 }
314 ck = NULL;
315out:
316 rcu_read_unlock();
317 mutex_unlock(lock: &c->lock);
318 return ck;
319}
320
321static struct bkey_cached *
322btree_key_cache_create(struct btree_trans *trans, struct btree_path *path)
323{
324 struct bch_fs *c = trans->c;
325 struct btree_key_cache *bc = &c->btree_key_cache;
326 struct bkey_cached *ck;
327 bool was_new = false;
328
329 ck = bkey_cached_alloc(trans, path, was_new: &was_new);
330 if (IS_ERR(ptr: ck))
331 return ck;
332
333 if (unlikely(!ck)) {
334 ck = bkey_cached_reuse(c: bc);
335 if (unlikely(!ck)) {
336 bch_err(c, "error allocating memory for key cache item, btree %s",
337 bch2_btree_id_str(path->btree_id));
338 return ERR_PTR(error: -BCH_ERR_ENOMEM_btree_key_cache_create);
339 }
340
341 mark_btree_node_locked(trans, path, level: 0, type: BTREE_NODE_INTENT_LOCKED);
342 }
343
344 ck->c.level = 0;
345 ck->c.btree_id = path->btree_id;
346 ck->key.btree_id = path->btree_id;
347 ck->key.pos = path->pos;
348 ck->valid = false;
349 ck->flags = 1U << BKEY_CACHED_ACCESSED;
350
351 if (unlikely(rhashtable_lookup_insert_fast(&bc->table,
352 &ck->hash,
353 bch2_btree_key_cache_params))) {
354 /* We raced with another fill: */
355
356 if (likely(was_new)) {
357 six_unlock_write(lock: &ck->c.lock);
358 six_unlock_intent(lock: &ck->c.lock);
359 kfree(objp: ck);
360 } else {
361 bkey_cached_free_fast(bc, ck);
362 }
363
364 mark_btree_node_locked(trans, path, level: 0, type: BTREE_NODE_UNLOCKED);
365 return NULL;
366 }
367
368 atomic_long_inc(v: &bc->nr_keys);
369
370 six_unlock_write(lock: &ck->c.lock);
371
372 return ck;
373}
374
375static int btree_key_cache_fill(struct btree_trans *trans,
376 struct btree_path *ck_path,
377 struct bkey_cached *ck)
378{
379 struct btree_iter iter;
380 struct bkey_s_c k;
381 unsigned new_u64s = 0;
382 struct bkey_i *new_k = NULL;
383 int ret;
384
385 bch2_trans_iter_init(trans, iter: &iter, btree_id: ck->key.btree_id, pos: ck->key.pos,
386 flags: BTREE_ITER_KEY_CACHE_FILL|
387 BTREE_ITER_CACHED_NOFILL);
388 iter.flags &= ~BTREE_ITER_WITH_JOURNAL;
389 k = bch2_btree_iter_peek_slot(&iter);
390 ret = bkey_err(k);
391 if (ret)
392 goto err;
393
394 if (!bch2_btree_node_relock(trans, path: ck_path, level: 0)) {
395 trace_and_count(trans->c, trans_restart_relock_key_cache_fill, trans, _THIS_IP_, ck_path);
396 ret = btree_trans_restart(trans, err: BCH_ERR_transaction_restart_key_cache_fill);
397 goto err;
398 }
399
400 /*
401 * bch2_varint_decode can read past the end of the buffer by at
402 * most 7 bytes (it won't be used):
403 */
404 new_u64s = k.k->u64s + 1;
405
406 /*
407 * Allocate some extra space so that the transaction commit path is less
408 * likely to have to reallocate, since that requires a transaction
409 * restart:
410 */
411 new_u64s = min(256U, (new_u64s * 3) / 2);
412
413 if (new_u64s > ck->u64s) {
414 new_u64s = roundup_pow_of_two(new_u64s);
415 new_k = kmalloc(size: new_u64s * sizeof(u64), GFP_NOWAIT|__GFP_NOWARN);
416 if (!new_k) {
417 bch2_trans_unlock(trans);
418
419 new_k = kmalloc(size: new_u64s * sizeof(u64), GFP_KERNEL);
420 if (!new_k) {
421 bch_err(trans->c, "error allocating memory for key cache key, btree %s u64s %u",
422 bch2_btree_id_str(ck->key.btree_id), new_u64s);
423 ret = -BCH_ERR_ENOMEM_btree_key_cache_fill;
424 goto err;
425 }
426
427 if (!bch2_btree_node_relock(trans, path: ck_path, level: 0)) {
428 kfree(objp: new_k);
429 trace_and_count(trans->c, trans_restart_relock_key_cache_fill, trans, _THIS_IP_, ck_path);
430 ret = btree_trans_restart(trans, err: BCH_ERR_transaction_restart_key_cache_fill);
431 goto err;
432 }
433
434 ret = bch2_trans_relock(trans);
435 if (ret) {
436 kfree(objp: new_k);
437 goto err;
438 }
439 }
440 }
441
442 ret = bch2_btree_node_lock_write(trans, path: ck_path, b: &ck_path->l[0].b->c);
443 if (ret) {
444 kfree(objp: new_k);
445 goto err;
446 }
447
448 if (new_k) {
449 kfree(objp: ck->k);
450 ck->u64s = new_u64s;
451 ck->k = new_k;
452 }
453
454 bkey_reassemble(dst: ck->k, src: k);
455 ck->valid = true;
456 bch2_btree_node_unlock_write(trans, ck_path, ck_path->l[0].b);
457
458 /* We're not likely to need this iterator again: */
459 set_btree_iter_dontneed(&iter);
460err:
461 bch2_trans_iter_exit(trans, &iter);
462 return ret;
463}
464
465static noinline int
466bch2_btree_path_traverse_cached_slowpath(struct btree_trans *trans, struct btree_path *path,
467 unsigned flags)
468{
469 struct bch_fs *c = trans->c;
470 struct bkey_cached *ck;
471 int ret = 0;
472
473 BUG_ON(path->level);
474
475 path->l[1].b = NULL;
476
477 if (bch2_btree_node_relock_notrace(trans, path, level: 0)) {
478 ck = (void *) path->l[0].b;
479 goto fill;
480 }
481retry:
482 ck = bch2_btree_key_cache_find(c, btree_id: path->btree_id, pos: path->pos);
483 if (!ck) {
484 ck = btree_key_cache_create(trans, path);
485 ret = PTR_ERR_OR_ZERO(ptr: ck);
486 if (ret)
487 goto err;
488 if (!ck)
489 goto retry;
490
491 mark_btree_node_locked(trans, path, level: 0, type: BTREE_NODE_INTENT_LOCKED);
492 path->locks_want = 1;
493 } else {
494 enum six_lock_type lock_want = __btree_lock_want(path, level: 0);
495
496 ret = btree_node_lock(trans, path, b: (void *) ck, level: 0,
497 type: lock_want, _THIS_IP_);
498 if (bch2_err_matches(ret, BCH_ERR_transaction_restart))
499 goto err;
500
501 BUG_ON(ret);
502
503 if (ck->key.btree_id != path->btree_id ||
504 !bpos_eq(l: ck->key.pos, r: path->pos)) {
505 six_unlock_type(lock: &ck->c.lock, type: lock_want);
506 goto retry;
507 }
508
509 mark_btree_node_locked(trans, path, level: 0,
510 type: (enum btree_node_locked_type) lock_want);
511 }
512
513 path->l[0].lock_seq = six_lock_seq(lock: &ck->c.lock);
514 path->l[0].b = (void *) ck;
515fill:
516 path->uptodate = BTREE_ITER_UPTODATE;
517
518 if (!ck->valid && !(flags & BTREE_ITER_CACHED_NOFILL)) {
519 /*
520 * Using the underscore version because we haven't set
521 * path->uptodate yet:
522 */
523 if (!path->locks_want &&
524 !__bch2_btree_path_upgrade(trans, path, 1, NULL)) {
525 trace_and_count(trans->c, trans_restart_key_cache_upgrade, trans, _THIS_IP_);
526 ret = btree_trans_restart(trans, err: BCH_ERR_transaction_restart_key_cache_upgrade);
527 goto err;
528 }
529
530 ret = btree_key_cache_fill(trans, ck_path: path, ck);
531 if (ret)
532 goto err;
533
534 ret = bch2_btree_path_relock(trans, path, _THIS_IP_);
535 if (ret)
536 goto err;
537
538 path->uptodate = BTREE_ITER_UPTODATE;
539 }
540
541 if (!test_bit(BKEY_CACHED_ACCESSED, &ck->flags))
542 set_bit(BKEY_CACHED_ACCESSED, addr: &ck->flags);
543
544 BUG_ON(btree_node_locked_type(path, 0) != btree_lock_want(path, 0));
545 BUG_ON(path->uptodate);
546
547 return ret;
548err:
549 path->uptodate = BTREE_ITER_NEED_TRAVERSE;
550 if (!bch2_err_matches(ret, BCH_ERR_transaction_restart)) {
551 btree_node_unlock(trans, path, level: 0);
552 path->l[0].b = ERR_PTR(error: ret);
553 }
554 return ret;
555}
556
557int bch2_btree_path_traverse_cached(struct btree_trans *trans, struct btree_path *path,
558 unsigned flags)
559{
560 struct bch_fs *c = trans->c;
561 struct bkey_cached *ck;
562 int ret = 0;
563
564 EBUG_ON(path->level);
565
566 path->l[1].b = NULL;
567
568 if (bch2_btree_node_relock_notrace(trans, path, level: 0)) {
569 ck = (void *) path->l[0].b;
570 goto fill;
571 }
572retry:
573 ck = bch2_btree_key_cache_find(c, btree_id: path->btree_id, pos: path->pos);
574 if (!ck) {
575 return bch2_btree_path_traverse_cached_slowpath(trans, path, flags);
576 } else {
577 enum six_lock_type lock_want = __btree_lock_want(path, level: 0);
578
579 ret = btree_node_lock(trans, path, b: (void *) ck, level: 0,
580 type: lock_want, _THIS_IP_);
581 EBUG_ON(ret && !bch2_err_matches(ret, BCH_ERR_transaction_restart));
582
583 if (ret)
584 return ret;
585
586 if (ck->key.btree_id != path->btree_id ||
587 !bpos_eq(l: ck->key.pos, r: path->pos)) {
588 six_unlock_type(lock: &ck->c.lock, type: lock_want);
589 goto retry;
590 }
591
592 mark_btree_node_locked(trans, path, level: 0,
593 type: (enum btree_node_locked_type) lock_want);
594 }
595
596 path->l[0].lock_seq = six_lock_seq(lock: &ck->c.lock);
597 path->l[0].b = (void *) ck;
598fill:
599 if (!ck->valid)
600 return bch2_btree_path_traverse_cached_slowpath(trans, path, flags);
601
602 if (!test_bit(BKEY_CACHED_ACCESSED, &ck->flags))
603 set_bit(BKEY_CACHED_ACCESSED, addr: &ck->flags);
604
605 path->uptodate = BTREE_ITER_UPTODATE;
606 EBUG_ON(!ck->valid);
607 EBUG_ON(btree_node_locked_type(path, 0) != btree_lock_want(path, 0));
608
609 return ret;
610}
611
612static int btree_key_cache_flush_pos(struct btree_trans *trans,
613 struct bkey_cached_key key,
614 u64 journal_seq,
615 unsigned commit_flags,
616 bool evict)
617{
618 struct bch_fs *c = trans->c;
619 struct journal *j = &c->journal;
620 struct btree_iter c_iter, b_iter;
621 struct bkey_cached *ck = NULL;
622 int ret;
623
624 bch2_trans_iter_init(trans, iter: &b_iter, btree_id: key.btree_id, pos: key.pos,
625 flags: BTREE_ITER_SLOTS|
626 BTREE_ITER_INTENT|
627 BTREE_ITER_ALL_SNAPSHOTS);
628 bch2_trans_iter_init(trans, iter: &c_iter, btree_id: key.btree_id, pos: key.pos,
629 flags: BTREE_ITER_CACHED|
630 BTREE_ITER_INTENT);
631 b_iter.flags &= ~BTREE_ITER_WITH_KEY_CACHE;
632
633 ret = bch2_btree_iter_traverse(&c_iter);
634 if (ret)
635 goto out;
636
637 ck = (void *) btree_iter_path(trans, iter: &c_iter)->l[0].b;
638 if (!ck)
639 goto out;
640
641 if (!test_bit(BKEY_CACHED_DIRTY, &ck->flags)) {
642 if (evict)
643 goto evict;
644 goto out;
645 }
646
647 BUG_ON(!ck->valid);
648
649 if (journal_seq && ck->journal.seq != journal_seq)
650 goto out;
651
652 trans->journal_res.seq = ck->journal.seq;
653
654 /*
655 * If we're at the end of the journal, we really want to free up space
656 * in the journal right away - we don't want to pin that old journal
657 * sequence number with a new btree node write, we want to re-journal
658 * the update
659 */
660 if (ck->journal.seq == journal_last_seq(j))
661 commit_flags |= BCH_WATERMARK_reclaim;
662
663 if (ck->journal.seq != journal_last_seq(j) ||
664 !test_bit(JOURNAL_SPACE_LOW, &c->journal.flags))
665 commit_flags |= BCH_TRANS_COMMIT_no_journal_res;
666
667 ret = bch2_btree_iter_traverse(&b_iter) ?:
668 bch2_trans_update(trans, &b_iter, ck->k,
669 BTREE_UPDATE_KEY_CACHE_RECLAIM|
670 BTREE_UPDATE_INTERNAL_SNAPSHOT_NODE|
671 BTREE_TRIGGER_NORUN) ?:
672 bch2_trans_commit(trans, NULL, NULL,
673 flags: BCH_TRANS_COMMIT_no_check_rw|
674 BCH_TRANS_COMMIT_no_enospc|
675 commit_flags);
676
677 bch2_fs_fatal_err_on(ret &&
678 !bch2_err_matches(ret, BCH_ERR_transaction_restart) &&
679 !bch2_err_matches(ret, BCH_ERR_journal_reclaim_would_deadlock) &&
680 !bch2_journal_error(j), c,
681 "flushing key cache: %s", bch2_err_str(ret));
682 if (ret)
683 goto out;
684
685 bch2_journal_pin_drop(j, &ck->journal);
686
687 struct btree_path *path = btree_iter_path(trans, iter: &c_iter);
688 BUG_ON(!btree_node_locked(path, 0));
689
690 if (!evict) {
691 if (test_bit(BKEY_CACHED_DIRTY, &ck->flags)) {
692 clear_bit(BKEY_CACHED_DIRTY, addr: &ck->flags);
693 atomic_long_dec(v: &c->btree_key_cache.nr_dirty);
694 }
695 } else {
696 struct btree_path *path2;
697 unsigned i;
698evict:
699 trans_for_each_path(trans, path2, i)
700 if (path2 != path)
701 __bch2_btree_path_unlock(trans, path: path2);
702
703 bch2_btree_node_lock_write_nofail(trans, path, &ck->c);
704
705 if (test_bit(BKEY_CACHED_DIRTY, &ck->flags)) {
706 clear_bit(BKEY_CACHED_DIRTY, addr: &ck->flags);
707 atomic_long_dec(v: &c->btree_key_cache.nr_dirty);
708 }
709
710 mark_btree_node_locked_noreset(path, level: 0, type: BTREE_NODE_UNLOCKED);
711 bkey_cached_evict(c: &c->btree_key_cache, ck);
712 bkey_cached_free_fast(bc: &c->btree_key_cache, ck);
713 }
714out:
715 bch2_trans_iter_exit(trans, &b_iter);
716 bch2_trans_iter_exit(trans, &c_iter);
717 return ret;
718}
719
720int bch2_btree_key_cache_journal_flush(struct journal *j,
721 struct journal_entry_pin *pin, u64 seq)
722{
723 struct bch_fs *c = container_of(j, struct bch_fs, journal);
724 struct bkey_cached *ck =
725 container_of(pin, struct bkey_cached, journal);
726 struct bkey_cached_key key;
727 struct btree_trans *trans = bch2_trans_get(c);
728 int srcu_idx = srcu_read_lock(ssp: &c->btree_trans_barrier);
729 int ret = 0;
730
731 btree_node_lock_nopath_nofail(trans, b: &ck->c, type: SIX_LOCK_read);
732 key = ck->key;
733
734 if (ck->journal.seq != seq ||
735 !test_bit(BKEY_CACHED_DIRTY, &ck->flags)) {
736 six_unlock_read(lock: &ck->c.lock);
737 goto unlock;
738 }
739
740 if (ck->seq != seq) {
741 bch2_journal_pin_update(j: &c->journal, seq: ck->seq, pin: &ck->journal,
742 flush_fn: bch2_btree_key_cache_journal_flush);
743 six_unlock_read(lock: &ck->c.lock);
744 goto unlock;
745 }
746 six_unlock_read(lock: &ck->c.lock);
747
748 ret = lockrestart_do(trans,
749 btree_key_cache_flush_pos(trans, key, seq,
750 BCH_TRANS_COMMIT_journal_reclaim, false));
751unlock:
752 srcu_read_unlock(ssp: &c->btree_trans_barrier, idx: srcu_idx);
753
754 bch2_trans_put(trans);
755 return ret;
756}
757
758bool bch2_btree_insert_key_cached(struct btree_trans *trans,
759 unsigned flags,
760 struct btree_insert_entry *insert_entry)
761{
762 struct bch_fs *c = trans->c;
763 struct bkey_cached *ck = (void *) (trans->paths + insert_entry->path)->l[0].b;
764 struct bkey_i *insert = insert_entry->k;
765 bool kick_reclaim = false;
766
767 BUG_ON(insert->k.u64s > ck->u64s);
768
769 bkey_copy(dst: ck->k, src: insert);
770 ck->valid = true;
771
772 if (!test_bit(BKEY_CACHED_DIRTY, &ck->flags)) {
773 EBUG_ON(test_bit(BCH_FS_clean_shutdown, &c->flags));
774 set_bit(BKEY_CACHED_DIRTY, addr: &ck->flags);
775 atomic_long_inc(v: &c->btree_key_cache.nr_dirty);
776
777 if (bch2_nr_btree_keys_need_flush(c))
778 kick_reclaim = true;
779 }
780
781 /*
782 * To minimize lock contention, we only add the journal pin here and
783 * defer pin updates to the flush callback via ->seq. Be careful not to
784 * update ->seq on nojournal commits because we don't want to update the
785 * pin to a seq that doesn't include journal updates on disk. Otherwise
786 * we risk losing the update after a crash.
787 *
788 * The only exception is if the pin is not active in the first place. We
789 * have to add the pin because journal reclaim drives key cache
790 * flushing. The flush callback will not proceed unless ->seq matches
791 * the latest pin, so make sure it starts with a consistent value.
792 */
793 if (!(insert_entry->flags & BTREE_UPDATE_NOJOURNAL) ||
794 !journal_pin_active(pin: &ck->journal)) {
795 ck->seq = trans->journal_res.seq;
796 }
797 bch2_journal_pin_add(j: &c->journal, seq: trans->journal_res.seq,
798 pin: &ck->journal, flush_fn: bch2_btree_key_cache_journal_flush);
799
800 if (kick_reclaim)
801 journal_reclaim_kick(j: &c->journal);
802 return true;
803}
804
805void bch2_btree_key_cache_drop(struct btree_trans *trans,
806 struct btree_path *path)
807{
808 struct bch_fs *c = trans->c;
809 struct bkey_cached *ck = (void *) path->l[0].b;
810
811 BUG_ON(!ck->valid);
812
813 /*
814 * We just did an update to the btree, bypassing the key cache: the key
815 * cache key is now stale and must be dropped, even if dirty:
816 */
817 if (test_bit(BKEY_CACHED_DIRTY, &ck->flags)) {
818 clear_bit(BKEY_CACHED_DIRTY, addr: &ck->flags);
819 atomic_long_dec(v: &c->btree_key_cache.nr_dirty);
820 bch2_journal_pin_drop(&c->journal, &ck->journal);
821 }
822
823 ck->valid = false;
824}
825
826static unsigned long bch2_btree_key_cache_scan(struct shrinker *shrink,
827 struct shrink_control *sc)
828{
829 struct bch_fs *c = shrink->private_data;
830 struct btree_key_cache *bc = &c->btree_key_cache;
831 struct bucket_table *tbl;
832 struct bkey_cached *ck, *t;
833 size_t scanned = 0, freed = 0, nr = sc->nr_to_scan;
834 unsigned start, flags;
835 int srcu_idx;
836
837 mutex_lock(&bc->lock);
838 srcu_idx = srcu_read_lock(ssp: &c->btree_trans_barrier);
839 flags = memalloc_nofs_save();
840
841 /*
842 * Newest freed entries are at the end of the list - once we hit one
843 * that's too new to be freed, we can bail out:
844 */
845 list_for_each_entry_safe(ck, t, &bc->freed_nonpcpu, list) {
846 if (!poll_state_synchronize_srcu(ssp: &c->btree_trans_barrier,
847 cookie: ck->btree_trans_barrier_seq))
848 break;
849
850 list_del(entry: &ck->list);
851 six_lock_exit(lock: &ck->c.lock);
852 kmem_cache_free(s: bch2_key_cache, objp: ck);
853 atomic_long_dec(v: &bc->nr_freed);
854 freed++;
855 bc->nr_freed_nonpcpu--;
856 }
857
858 list_for_each_entry_safe(ck, t, &bc->freed_pcpu, list) {
859 if (!poll_state_synchronize_srcu(ssp: &c->btree_trans_barrier,
860 cookie: ck->btree_trans_barrier_seq))
861 break;
862
863 list_del(entry: &ck->list);
864 six_lock_exit(lock: &ck->c.lock);
865 kmem_cache_free(s: bch2_key_cache, objp: ck);
866 atomic_long_dec(v: &bc->nr_freed);
867 freed++;
868 bc->nr_freed_pcpu--;
869 }
870
871 rcu_read_lock();
872 tbl = rht_dereference_rcu(bc->table.tbl, &bc->table);
873 if (bc->shrink_iter >= tbl->size)
874 bc->shrink_iter = 0;
875 start = bc->shrink_iter;
876
877 do {
878 struct rhash_head *pos, *next;
879
880 pos = rht_ptr_rcu(bkt: rht_bucket(tbl, hash: bc->shrink_iter));
881
882 while (!rht_is_a_nulls(ptr: pos)) {
883 next = rht_dereference_bucket_rcu(pos->next, tbl, bc->shrink_iter);
884 ck = container_of(pos, struct bkey_cached, hash);
885
886 if (test_bit(BKEY_CACHED_DIRTY, &ck->flags)) {
887 goto next;
888 } else if (test_bit(BKEY_CACHED_ACCESSED, &ck->flags)) {
889 clear_bit(BKEY_CACHED_ACCESSED, addr: &ck->flags);
890 goto next;
891 } else if (bkey_cached_lock_for_evict(ck)) {
892 bkey_cached_evict(c: bc, ck);
893 bkey_cached_free(bc, ck);
894 }
895
896 scanned++;
897 if (scanned >= nr)
898 break;
899next:
900 pos = next;
901 }
902
903 bc->shrink_iter++;
904 if (bc->shrink_iter >= tbl->size)
905 bc->shrink_iter = 0;
906 } while (scanned < nr && bc->shrink_iter != start);
907
908 rcu_read_unlock();
909 memalloc_nofs_restore(flags);
910 srcu_read_unlock(ssp: &c->btree_trans_barrier, idx: srcu_idx);
911 mutex_unlock(lock: &bc->lock);
912
913 return freed;
914}
915
916static unsigned long bch2_btree_key_cache_count(struct shrinker *shrink,
917 struct shrink_control *sc)
918{
919 struct bch_fs *c = shrink->private_data;
920 struct btree_key_cache *bc = &c->btree_key_cache;
921 long nr = atomic_long_read(v: &bc->nr_keys) -
922 atomic_long_read(v: &bc->nr_dirty);
923
924 return max(0L, nr);
925}
926
927void bch2_fs_btree_key_cache_exit(struct btree_key_cache *bc)
928{
929 struct bch_fs *c = container_of(bc, struct bch_fs, btree_key_cache);
930 struct bucket_table *tbl;
931 struct bkey_cached *ck, *n;
932 struct rhash_head *pos;
933 LIST_HEAD(items);
934 unsigned i;
935#ifdef __KERNEL__
936 int cpu;
937#endif
938
939 shrinker_free(shrinker: bc->shrink);
940
941 mutex_lock(&bc->lock);
942
943 /*
944 * The loop is needed to guard against racing with rehash:
945 */
946 while (atomic_long_read(v: &bc->nr_keys)) {
947 rcu_read_lock();
948 tbl = rht_dereference_rcu(bc->table.tbl, &bc->table);
949 if (tbl)
950 for (i = 0; i < tbl->size; i++)
951 rht_for_each_entry_rcu(ck, pos, tbl, i, hash) {
952 bkey_cached_evict(c: bc, ck);
953 list_add(new: &ck->list, head: &items);
954 }
955 rcu_read_unlock();
956 }
957
958#ifdef __KERNEL__
959 for_each_possible_cpu(cpu) {
960 struct btree_key_cache_freelist *f =
961 per_cpu_ptr(bc->pcpu_freed, cpu);
962
963 for (i = 0; i < f->nr; i++) {
964 ck = f->objs[i];
965 list_add(new: &ck->list, head: &items);
966 }
967 }
968#endif
969
970 BUG_ON(list_count_nodes(&bc->freed_pcpu) != bc->nr_freed_pcpu);
971 BUG_ON(list_count_nodes(&bc->freed_nonpcpu) != bc->nr_freed_nonpcpu);
972
973 list_splice(list: &bc->freed_pcpu, head: &items);
974 list_splice(list: &bc->freed_nonpcpu, head: &items);
975
976 mutex_unlock(lock: &bc->lock);
977
978 list_for_each_entry_safe(ck, n, &items, list) {
979 cond_resched();
980
981 list_del(entry: &ck->list);
982 kfree(objp: ck->k);
983 six_lock_exit(lock: &ck->c.lock);
984 kmem_cache_free(s: bch2_key_cache, objp: ck);
985 }
986
987 if (atomic_long_read(v: &bc->nr_dirty) &&
988 !bch2_journal_error(j: &c->journal) &&
989 test_bit(BCH_FS_was_rw, &c->flags))
990 panic(fmt: "btree key cache shutdown error: nr_dirty nonzero (%li)\n",
991 atomic_long_read(v: &bc->nr_dirty));
992
993 if (atomic_long_read(v: &bc->nr_keys))
994 panic(fmt: "btree key cache shutdown error: nr_keys nonzero (%li)\n",
995 atomic_long_read(v: &bc->nr_keys));
996
997 if (bc->table_init_done)
998 rhashtable_destroy(ht: &bc->table);
999
1000 free_percpu(pdata: bc->pcpu_freed);
1001}
1002
1003void bch2_fs_btree_key_cache_init_early(struct btree_key_cache *c)
1004{
1005 mutex_init(&c->lock);
1006 INIT_LIST_HEAD(list: &c->freed_pcpu);
1007 INIT_LIST_HEAD(list: &c->freed_nonpcpu);
1008}
1009
1010int bch2_fs_btree_key_cache_init(struct btree_key_cache *bc)
1011{
1012 struct bch_fs *c = container_of(bc, struct bch_fs, btree_key_cache);
1013 struct shrinker *shrink;
1014
1015#ifdef __KERNEL__
1016 bc->pcpu_freed = alloc_percpu(struct btree_key_cache_freelist);
1017 if (!bc->pcpu_freed)
1018 return -BCH_ERR_ENOMEM_fs_btree_cache_init;
1019#endif
1020
1021 if (rhashtable_init(ht: &bc->table, params: &bch2_btree_key_cache_params))
1022 return -BCH_ERR_ENOMEM_fs_btree_cache_init;
1023
1024 bc->table_init_done = true;
1025
1026 shrink = shrinker_alloc(flags: 0, fmt: "%s-btree_key_cache", c->name);
1027 if (!shrink)
1028 return -BCH_ERR_ENOMEM_fs_btree_cache_init;
1029 bc->shrink = shrink;
1030 shrink->seeks = 0;
1031 shrink->count_objects = bch2_btree_key_cache_count;
1032 shrink->scan_objects = bch2_btree_key_cache_scan;
1033 shrink->private_data = c;
1034 shrinker_register(shrinker: shrink);
1035 return 0;
1036}
1037
1038void bch2_btree_key_cache_to_text(struct printbuf *out, struct btree_key_cache *c)
1039{
1040 prt_printf(out, "nr_freed:\t%lu", atomic_long_read(&c->nr_freed));
1041 prt_newline(out);
1042 prt_printf(out, "nr_keys:\t%lu", atomic_long_read(&c->nr_keys));
1043 prt_newline(out);
1044 prt_printf(out, "nr_dirty:\t%lu", atomic_long_read(&c->nr_dirty));
1045 prt_newline(out);
1046}
1047
1048void bch2_btree_key_cache_exit(void)
1049{
1050 kmem_cache_destroy(s: bch2_key_cache);
1051}
1052
1053int __init bch2_btree_key_cache_init(void)
1054{
1055 bch2_key_cache = KMEM_CACHE(bkey_cached, SLAB_RECLAIM_ACCOUNT);
1056 if (!bch2_key_cache)
1057 return -ENOMEM;
1058
1059 return 0;
1060}
1061

source code of linux/fs/bcachefs/btree_key_cache.c