1// SPDX-License-Identifier: GPL-2.0
2
3#include "bcachefs.h"
4#include "btree_key_cache.h"
5#include "btree_update.h"
6#include "btree_write_buffer.h"
7#include "buckets.h"
8#include "errcode.h"
9#include "error.h"
10#include "journal.h"
11#include "journal_io.h"
12#include "journal_reclaim.h"
13#include "replicas.h"
14#include "sb-members.h"
15#include "trace.h"
16
17#include <linux/kthread.h>
18#include <linux/sched/mm.h>
19
20/* Free space calculations: */
21
22static unsigned journal_space_from(struct journal_device *ja,
23 enum journal_space_from from)
24{
25 switch (from) {
26 case journal_space_discarded:
27 return ja->discard_idx;
28 case journal_space_clean_ondisk:
29 return ja->dirty_idx_ondisk;
30 case journal_space_clean:
31 return ja->dirty_idx;
32 default:
33 BUG();
34 }
35}
36
37unsigned bch2_journal_dev_buckets_available(struct journal *j,
38 struct journal_device *ja,
39 enum journal_space_from from)
40{
41 unsigned available = (journal_space_from(ja, from) -
42 ja->cur_idx - 1 + ja->nr) % ja->nr;
43
44 /*
45 * Don't use the last bucket unless writing the new last_seq
46 * will make another bucket available:
47 */
48 if (available && ja->dirty_idx_ondisk == ja->dirty_idx)
49 --available;
50
51 return available;
52}
53
54void bch2_journal_set_watermark(struct journal *j)
55{
56 struct bch_fs *c = container_of(j, struct bch_fs, journal);
57 bool low_on_space = j->space[journal_space_clean].total * 4 <=
58 j->space[journal_space_total].total;
59 bool low_on_pin = fifo_free(&j->pin) < j->pin.size / 4;
60 bool low_on_wb = bch2_btree_write_buffer_must_wait(c);
61 unsigned watermark = low_on_space || low_on_pin || low_on_wb
62 ? BCH_WATERMARK_reclaim
63 : BCH_WATERMARK_stripe;
64
65 if (track_event_change(stats: &c->times[BCH_TIME_blocked_journal_low_on_space], v: low_on_space) ||
66 track_event_change(stats: &c->times[BCH_TIME_blocked_journal_low_on_pin], v: low_on_pin) ||
67 track_event_change(stats: &c->times[BCH_TIME_blocked_write_buffer_full], v: low_on_wb))
68 trace_and_count(c, journal_full, c);
69
70 mod_bit(nr: JOURNAL_SPACE_LOW, addr: &j->flags, v: low_on_space || low_on_pin);
71
72 swap(watermark, j->watermark);
73 if (watermark > j->watermark)
74 journal_wake(j);
75}
76
77static struct journal_space
78journal_dev_space_available(struct journal *j, struct bch_dev *ca,
79 enum journal_space_from from)
80{
81 struct journal_device *ja = &ca->journal;
82 unsigned sectors, buckets, unwritten;
83 u64 seq;
84
85 if (from == journal_space_total)
86 return (struct journal_space) {
87 .next_entry = ca->mi.bucket_size,
88 .total = ca->mi.bucket_size * ja->nr,
89 };
90
91 buckets = bch2_journal_dev_buckets_available(j, ja, from);
92 sectors = ja->sectors_free;
93
94 /*
95 * We that we don't allocate the space for a journal entry
96 * until we write it out - thus, account for it here:
97 */
98 for (seq = journal_last_unwritten_seq(j);
99 seq <= journal_cur_seq(j);
100 seq++) {
101 unwritten = j->buf[seq & JOURNAL_BUF_MASK].sectors;
102
103 if (!unwritten)
104 continue;
105
106 /* entry won't fit on this device, skip: */
107 if (unwritten > ca->mi.bucket_size)
108 continue;
109
110 if (unwritten >= sectors) {
111 if (!buckets) {
112 sectors = 0;
113 break;
114 }
115
116 buckets--;
117 sectors = ca->mi.bucket_size;
118 }
119
120 sectors -= unwritten;
121 }
122
123 if (sectors < ca->mi.bucket_size && buckets) {
124 buckets--;
125 sectors = ca->mi.bucket_size;
126 }
127
128 return (struct journal_space) {
129 .next_entry = sectors,
130 .total = sectors + buckets * ca->mi.bucket_size,
131 };
132}
133
134static struct journal_space __journal_space_available(struct journal *j, unsigned nr_devs_want,
135 enum journal_space_from from)
136{
137 struct bch_fs *c = container_of(j, struct bch_fs, journal);
138 unsigned pos, nr_devs = 0;
139 struct journal_space space, dev_space[BCH_SB_MEMBERS_MAX];
140
141 BUG_ON(nr_devs_want > ARRAY_SIZE(dev_space));
142
143 rcu_read_lock();
144 for_each_member_device_rcu(c, ca, &c->rw_devs[BCH_DATA_journal]) {
145 if (!ca->journal.nr)
146 continue;
147
148 space = journal_dev_space_available(j, ca, from);
149 if (!space.next_entry)
150 continue;
151
152 for (pos = 0; pos < nr_devs; pos++)
153 if (space.total > dev_space[pos].total)
154 break;
155
156 array_insert_item(dev_space, nr_devs, pos, space);
157 }
158 rcu_read_unlock();
159
160 if (nr_devs < nr_devs_want)
161 return (struct journal_space) { 0, 0 };
162
163 /*
164 * We sorted largest to smallest, and we want the smallest out of the
165 * @nr_devs_want largest devices:
166 */
167 return dev_space[nr_devs_want - 1];
168}
169
170void bch2_journal_space_available(struct journal *j)
171{
172 struct bch_fs *c = container_of(j, struct bch_fs, journal);
173 unsigned clean, clean_ondisk, total;
174 unsigned max_entry_size = min(j->buf[0].buf_size >> 9,
175 j->buf[1].buf_size >> 9);
176 unsigned nr_online = 0, nr_devs_want;
177 bool can_discard = false;
178 int ret = 0;
179
180 lockdep_assert_held(&j->lock);
181
182 rcu_read_lock();
183 for_each_member_device_rcu(c, ca, &c->rw_devs[BCH_DATA_journal]) {
184 struct journal_device *ja = &ca->journal;
185
186 if (!ja->nr)
187 continue;
188
189 while (ja->dirty_idx != ja->cur_idx &&
190 ja->bucket_seq[ja->dirty_idx] < journal_last_seq(j))
191 ja->dirty_idx = (ja->dirty_idx + 1) % ja->nr;
192
193 while (ja->dirty_idx_ondisk != ja->dirty_idx &&
194 ja->bucket_seq[ja->dirty_idx_ondisk] < j->last_seq_ondisk)
195 ja->dirty_idx_ondisk = (ja->dirty_idx_ondisk + 1) % ja->nr;
196
197 if (ja->discard_idx != ja->dirty_idx_ondisk)
198 can_discard = true;
199
200 max_entry_size = min_t(unsigned, max_entry_size, ca->mi.bucket_size);
201 nr_online++;
202 }
203 rcu_read_unlock();
204
205 j->can_discard = can_discard;
206
207 if (nr_online < metadata_replicas_required(c)) {
208 ret = JOURNAL_ERR_insufficient_devices;
209 goto out;
210 }
211
212 nr_devs_want = min_t(unsigned, nr_online, c->opts.metadata_replicas);
213
214 for (unsigned i = 0; i < journal_space_nr; i++)
215 j->space[i] = __journal_space_available(j, nr_devs_want, from: i);
216
217 clean_ondisk = j->space[journal_space_clean_ondisk].total;
218 clean = j->space[journal_space_clean].total;
219 total = j->space[journal_space_total].total;
220
221 if (!j->space[journal_space_discarded].next_entry)
222 ret = JOURNAL_ERR_journal_full;
223
224 if ((j->space[journal_space_clean_ondisk].next_entry <
225 j->space[journal_space_clean_ondisk].total) &&
226 (clean - clean_ondisk <= total / 8) &&
227 (clean_ondisk * 2 > clean))
228 set_bit(nr: JOURNAL_MAY_SKIP_FLUSH, addr: &j->flags);
229 else
230 clear_bit(nr: JOURNAL_MAY_SKIP_FLUSH, addr: &j->flags);
231
232 bch2_journal_set_watermark(j);
233out:
234 j->cur_entry_sectors = !ret ? j->space[journal_space_discarded].next_entry : 0;
235 j->cur_entry_error = ret;
236
237 if (!ret)
238 journal_wake(j);
239}
240
241/* Discards - last part of journal reclaim: */
242
243static bool should_discard_bucket(struct journal *j, struct journal_device *ja)
244{
245 bool ret;
246
247 spin_lock(lock: &j->lock);
248 ret = ja->discard_idx != ja->dirty_idx_ondisk;
249 spin_unlock(lock: &j->lock);
250
251 return ret;
252}
253
254/*
255 * Advance ja->discard_idx as long as it points to buckets that are no longer
256 * dirty, issuing discards if necessary:
257 */
258void bch2_journal_do_discards(struct journal *j)
259{
260 struct bch_fs *c = container_of(j, struct bch_fs, journal);
261
262 mutex_lock(&j->discard_lock);
263
264 for_each_rw_member(c, ca) {
265 struct journal_device *ja = &ca->journal;
266
267 while (should_discard_bucket(j, ja)) {
268 if (!c->opts.nochanges &&
269 ca->mi.discard &&
270 bdev_max_discard_sectors(bdev: ca->disk_sb.bdev))
271 blkdev_issue_discard(bdev: ca->disk_sb.bdev,
272 sector: bucket_to_sector(ca,
273 b: ja->buckets[ja->discard_idx]),
274 nr_sects: ca->mi.bucket_size, GFP_NOFS);
275
276 spin_lock(lock: &j->lock);
277 ja->discard_idx = (ja->discard_idx + 1) % ja->nr;
278
279 bch2_journal_space_available(j);
280 spin_unlock(lock: &j->lock);
281 }
282 }
283
284 mutex_unlock(lock: &j->discard_lock);
285}
286
287/*
288 * Journal entry pinning - machinery for holding a reference on a given journal
289 * entry, holding it open to ensure it gets replayed during recovery:
290 */
291
292void bch2_journal_reclaim_fast(struct journal *j)
293{
294 bool popped = false;
295
296 lockdep_assert_held(&j->lock);
297
298 /*
299 * Unpin journal entries whose reference counts reached zero, meaning
300 * all btree nodes got written out
301 */
302 while (!fifo_empty(&j->pin) &&
303 j->pin.front <= j->seq_ondisk &&
304 !atomic_read(v: &fifo_peek_front(&j->pin).count)) {
305 j->pin.front++;
306 popped = true;
307 }
308
309 if (popped)
310 bch2_journal_space_available(j);
311}
312
313bool __bch2_journal_pin_put(struct journal *j, u64 seq)
314{
315 struct journal_entry_pin_list *pin_list = journal_seq_pin(j, seq);
316
317 return atomic_dec_and_test(v: &pin_list->count);
318}
319
320void bch2_journal_pin_put(struct journal *j, u64 seq)
321{
322 if (__bch2_journal_pin_put(j, seq)) {
323 spin_lock(lock: &j->lock);
324 bch2_journal_reclaim_fast(j);
325 spin_unlock(lock: &j->lock);
326 }
327}
328
329static inline bool __journal_pin_drop(struct journal *j,
330 struct journal_entry_pin *pin)
331{
332 struct journal_entry_pin_list *pin_list;
333
334 if (!journal_pin_active(pin))
335 return false;
336
337 if (j->flush_in_progress == pin)
338 j->flush_in_progress_dropped = true;
339
340 pin_list = journal_seq_pin(j, seq: pin->seq);
341 pin->seq = 0;
342 list_del_init(entry: &pin->list);
343
344 /*
345 * Unpinning a journal entry may make journal_next_bucket() succeed, if
346 * writing a new last_seq will now make another bucket available:
347 */
348 return atomic_dec_and_test(v: &pin_list->count) &&
349 pin_list == &fifo_peek_front(&j->pin);
350}
351
352void bch2_journal_pin_drop(struct journal *j,
353 struct journal_entry_pin *pin)
354{
355 spin_lock(lock: &j->lock);
356 if (__journal_pin_drop(j, pin))
357 bch2_journal_reclaim_fast(j);
358 spin_unlock(lock: &j->lock);
359}
360
361static enum journal_pin_type journal_pin_type(journal_pin_flush_fn fn)
362{
363 if (fn == bch2_btree_node_flush0 ||
364 fn == bch2_btree_node_flush1)
365 return JOURNAL_PIN_btree;
366 else if (fn == bch2_btree_key_cache_journal_flush)
367 return JOURNAL_PIN_key_cache;
368 else
369 return JOURNAL_PIN_other;
370}
371
372static inline void bch2_journal_pin_set_locked(struct journal *j, u64 seq,
373 struct journal_entry_pin *pin,
374 journal_pin_flush_fn flush_fn,
375 enum journal_pin_type type)
376{
377 struct journal_entry_pin_list *pin_list = journal_seq_pin(j, seq);
378
379 /*
380 * flush_fn is how we identify journal pins in debugfs, so must always
381 * exist, even if it doesn't do anything:
382 */
383 BUG_ON(!flush_fn);
384
385 atomic_inc(v: &pin_list->count);
386 pin->seq = seq;
387 pin->flush = flush_fn;
388 list_add(new: &pin->list, head: &pin_list->list[type]);
389}
390
391void bch2_journal_pin_copy(struct journal *j,
392 struct journal_entry_pin *dst,
393 struct journal_entry_pin *src,
394 journal_pin_flush_fn flush_fn)
395{
396 spin_lock(lock: &j->lock);
397
398 u64 seq = READ_ONCE(src->seq);
399
400 if (seq < journal_last_seq(j)) {
401 /*
402 * bch2_journal_pin_copy() raced with bch2_journal_pin_drop() on
403 * the src pin - with the pin dropped, the entry to pin might no
404 * longer to exist, but that means there's no longer anything to
405 * copy and we can bail out here:
406 */
407 spin_unlock(lock: &j->lock);
408 return;
409 }
410
411 bool reclaim = __journal_pin_drop(j, pin: dst);
412
413 bch2_journal_pin_set_locked(j, seq, pin: dst, flush_fn, type: journal_pin_type(fn: flush_fn));
414
415 if (reclaim)
416 bch2_journal_reclaim_fast(j);
417
418 /*
419 * If the journal is currently full, we might want to call flush_fn
420 * immediately:
421 */
422 if (seq == journal_last_seq(j))
423 journal_wake(j);
424 spin_unlock(lock: &j->lock);
425}
426
427void bch2_journal_pin_set(struct journal *j, u64 seq,
428 struct journal_entry_pin *pin,
429 journal_pin_flush_fn flush_fn)
430{
431 spin_lock(lock: &j->lock);
432
433 BUG_ON(seq < journal_last_seq(j));
434
435 bool reclaim = __journal_pin_drop(j, pin);
436
437 bch2_journal_pin_set_locked(j, seq, pin, flush_fn, type: journal_pin_type(fn: flush_fn));
438
439 if (reclaim)
440 bch2_journal_reclaim_fast(j);
441 /*
442 * If the journal is currently full, we might want to call flush_fn
443 * immediately:
444 */
445 if (seq == journal_last_seq(j))
446 journal_wake(j);
447
448 spin_unlock(lock: &j->lock);
449}
450
451/**
452 * bch2_journal_pin_flush: ensure journal pin callback is no longer running
453 * @j: journal object
454 * @pin: pin to flush
455 */
456void bch2_journal_pin_flush(struct journal *j, struct journal_entry_pin *pin)
457{
458 BUG_ON(journal_pin_active(pin));
459
460 wait_event(j->pin_flush_wait, j->flush_in_progress != pin);
461}
462
463/*
464 * Journal reclaim: flush references to open journal entries to reclaim space in
465 * the journal
466 *
467 * May be done by the journal code in the background as needed to free up space
468 * for more journal entries, or as part of doing a clean shutdown, or to migrate
469 * data off of a specific device:
470 */
471
472static struct journal_entry_pin *
473journal_get_next_pin(struct journal *j,
474 u64 seq_to_flush,
475 unsigned allowed_below_seq,
476 unsigned allowed_above_seq,
477 u64 *seq)
478{
479 struct journal_entry_pin_list *pin_list;
480 struct journal_entry_pin *ret = NULL;
481 unsigned i;
482
483 fifo_for_each_entry_ptr(pin_list, &j->pin, *seq) {
484 if (*seq > seq_to_flush && !allowed_above_seq)
485 break;
486
487 for (i = 0; i < JOURNAL_PIN_NR; i++)
488 if ((((1U << i) & allowed_below_seq) && *seq <= seq_to_flush) ||
489 ((1U << i) & allowed_above_seq)) {
490 ret = list_first_entry_or_null(&pin_list->list[i],
491 struct journal_entry_pin, list);
492 if (ret)
493 return ret;
494 }
495 }
496
497 return NULL;
498}
499
500/* returns true if we did work */
501static size_t journal_flush_pins(struct journal *j,
502 u64 seq_to_flush,
503 unsigned allowed_below_seq,
504 unsigned allowed_above_seq,
505 unsigned min_any,
506 unsigned min_key_cache)
507{
508 struct journal_entry_pin *pin;
509 size_t nr_flushed = 0;
510 journal_pin_flush_fn flush_fn;
511 u64 seq;
512 int err;
513
514 lockdep_assert_held(&j->reclaim_lock);
515
516 while (1) {
517 unsigned allowed_above = allowed_above_seq;
518 unsigned allowed_below = allowed_below_seq;
519
520 if (min_any) {
521 allowed_above |= ~0;
522 allowed_below |= ~0;
523 }
524
525 if (min_key_cache) {
526 allowed_above |= 1U << JOURNAL_PIN_key_cache;
527 allowed_below |= 1U << JOURNAL_PIN_key_cache;
528 }
529
530 cond_resched();
531
532 j->last_flushed = jiffies;
533
534 spin_lock(lock: &j->lock);
535 pin = journal_get_next_pin(j, seq_to_flush, allowed_below_seq: allowed_below, allowed_above_seq: allowed_above, seq: &seq);
536 if (pin) {
537 BUG_ON(j->flush_in_progress);
538 j->flush_in_progress = pin;
539 j->flush_in_progress_dropped = false;
540 flush_fn = pin->flush;
541 }
542 spin_unlock(lock: &j->lock);
543
544 if (!pin)
545 break;
546
547 if (min_key_cache && pin->flush == bch2_btree_key_cache_journal_flush)
548 min_key_cache--;
549
550 if (min_any)
551 min_any--;
552
553 err = flush_fn(j, pin, seq);
554
555 spin_lock(lock: &j->lock);
556 /* Pin might have been dropped or rearmed: */
557 if (likely(!err && !j->flush_in_progress_dropped))
558 list_move(list: &pin->list, head: &journal_seq_pin(j, seq)->flushed);
559 j->flush_in_progress = NULL;
560 j->flush_in_progress_dropped = false;
561 spin_unlock(lock: &j->lock);
562
563 wake_up(&j->pin_flush_wait);
564
565 if (err)
566 break;
567
568 nr_flushed++;
569 }
570
571 return nr_flushed;
572}
573
574static u64 journal_seq_to_flush(struct journal *j)
575{
576 struct bch_fs *c = container_of(j, struct bch_fs, journal);
577 u64 seq_to_flush = 0;
578
579 spin_lock(lock: &j->lock);
580
581 for_each_rw_member(c, ca) {
582 struct journal_device *ja = &ca->journal;
583 unsigned nr_buckets, bucket_to_flush;
584
585 if (!ja->nr)
586 continue;
587
588 /* Try to keep the journal at most half full: */
589 nr_buckets = ja->nr / 2;
590
591 nr_buckets = min(nr_buckets, ja->nr);
592
593 bucket_to_flush = (ja->cur_idx + nr_buckets) % ja->nr;
594 seq_to_flush = max(seq_to_flush,
595 ja->bucket_seq[bucket_to_flush]);
596 }
597
598 /* Also flush if the pin fifo is more than half full */
599 seq_to_flush = max_t(s64, seq_to_flush,
600 (s64) journal_cur_seq(j) -
601 (j->pin.size >> 1));
602 spin_unlock(lock: &j->lock);
603
604 return seq_to_flush;
605}
606
607/**
608 * __bch2_journal_reclaim - free up journal buckets
609 * @j: journal object
610 * @direct: direct or background reclaim?
611 * @kicked: requested to run since we last ran?
612 * Returns: 0 on success, or -EIO if the journal has been shutdown
613 *
614 * Background journal reclaim writes out btree nodes. It should be run
615 * early enough so that we never completely run out of journal buckets.
616 *
617 * High watermarks for triggering background reclaim:
618 * - FIFO has fewer than 512 entries left
619 * - fewer than 25% journal buckets free
620 *
621 * Background reclaim runs until low watermarks are reached:
622 * - FIFO has more than 1024 entries left
623 * - more than 50% journal buckets free
624 *
625 * As long as a reclaim can complete in the time it takes to fill up
626 * 512 journal entries or 25% of all journal buckets, then
627 * journal_next_bucket() should not stall.
628 */
629static int __bch2_journal_reclaim(struct journal *j, bool direct, bool kicked)
630{
631 struct bch_fs *c = container_of(j, struct bch_fs, journal);
632 bool kthread = (current->flags & PF_KTHREAD) != 0;
633 u64 seq_to_flush;
634 size_t min_nr, min_key_cache, nr_flushed;
635 unsigned flags;
636 int ret = 0;
637
638 /*
639 * We can't invoke memory reclaim while holding the reclaim_lock -
640 * journal reclaim is required to make progress for memory reclaim
641 * (cleaning the caches), so we can't get stuck in memory reclaim while
642 * we're holding the reclaim lock:
643 */
644 lockdep_assert_held(&j->reclaim_lock);
645 flags = memalloc_noreclaim_save();
646
647 do {
648 if (kthread && kthread_should_stop())
649 break;
650
651 if (bch2_journal_error(j)) {
652 ret = -EIO;
653 break;
654 }
655
656 bch2_journal_do_discards(j);
657
658 seq_to_flush = journal_seq_to_flush(j);
659 min_nr = 0;
660
661 /*
662 * If it's been longer than j->reclaim_delay_ms since we last flushed,
663 * make sure to flush at least one journal pin:
664 */
665 if (time_after(jiffies, j->last_flushed +
666 msecs_to_jiffies(c->opts.journal_reclaim_delay)))
667 min_nr = 1;
668
669 if (j->watermark != BCH_WATERMARK_stripe)
670 min_nr = 1;
671
672 if (atomic_read(v: &c->btree_cache.dirty) * 2 > c->btree_cache.used)
673 min_nr = 1;
674
675 min_key_cache = min(bch2_nr_btree_keys_need_flush(c), (size_t) 128);
676
677 trace_and_count(c, journal_reclaim_start, c,
678 direct, kicked,
679 min_nr, min_key_cache,
680 atomic_read(&c->btree_cache.dirty),
681 c->btree_cache.used,
682 atomic_long_read(&c->btree_key_cache.nr_dirty),
683 atomic_long_read(&c->btree_key_cache.nr_keys));
684
685 nr_flushed = journal_flush_pins(j, seq_to_flush,
686 allowed_below_seq: ~0, allowed_above_seq: 0,
687 min_any: min_nr, min_key_cache);
688
689 if (direct)
690 j->nr_direct_reclaim += nr_flushed;
691 else
692 j->nr_background_reclaim += nr_flushed;
693 trace_and_count(c, journal_reclaim_finish, c, nr_flushed);
694
695 if (nr_flushed)
696 wake_up(&j->reclaim_wait);
697 } while ((min_nr || min_key_cache) && nr_flushed && !direct);
698
699 memalloc_noreclaim_restore(flags);
700
701 return ret;
702}
703
704int bch2_journal_reclaim(struct journal *j)
705{
706 return __bch2_journal_reclaim(j, direct: true, kicked: true);
707}
708
709static int bch2_journal_reclaim_thread(void *arg)
710{
711 struct journal *j = arg;
712 struct bch_fs *c = container_of(j, struct bch_fs, journal);
713 unsigned long delay, now;
714 bool journal_empty;
715 int ret = 0;
716
717 set_freezable();
718
719 j->last_flushed = jiffies;
720
721 while (!ret && !kthread_should_stop()) {
722 bool kicked = j->reclaim_kicked;
723
724 j->reclaim_kicked = false;
725
726 mutex_lock(&j->reclaim_lock);
727 ret = __bch2_journal_reclaim(j, direct: false, kicked);
728 mutex_unlock(lock: &j->reclaim_lock);
729
730 now = jiffies;
731 delay = msecs_to_jiffies(m: c->opts.journal_reclaim_delay);
732 j->next_reclaim = j->last_flushed + delay;
733
734 if (!time_in_range(j->next_reclaim, now, now + delay))
735 j->next_reclaim = now + delay;
736
737 while (1) {
738 set_current_state(TASK_INTERRUPTIBLE|TASK_FREEZABLE);
739 if (kthread_should_stop())
740 break;
741 if (j->reclaim_kicked)
742 break;
743
744 spin_lock(lock: &j->lock);
745 journal_empty = fifo_empty(&j->pin);
746 spin_unlock(lock: &j->lock);
747
748 if (journal_empty)
749 schedule();
750 else if (time_after(j->next_reclaim, jiffies))
751 schedule_timeout(timeout: j->next_reclaim - jiffies);
752 else
753 break;
754 }
755 __set_current_state(TASK_RUNNING);
756 }
757
758 return 0;
759}
760
761void bch2_journal_reclaim_stop(struct journal *j)
762{
763 struct task_struct *p = j->reclaim_thread;
764
765 j->reclaim_thread = NULL;
766
767 if (p) {
768 kthread_stop(k: p);
769 put_task_struct(t: p);
770 }
771}
772
773int bch2_journal_reclaim_start(struct journal *j)
774{
775 struct bch_fs *c = container_of(j, struct bch_fs, journal);
776 struct task_struct *p;
777 int ret;
778
779 if (j->reclaim_thread)
780 return 0;
781
782 p = kthread_create(bch2_journal_reclaim_thread, j,
783 "bch-reclaim/%s", c->name);
784 ret = PTR_ERR_OR_ZERO(ptr: p);
785 bch_err_msg(c, ret, "creating journal reclaim thread");
786 if (ret)
787 return ret;
788
789 get_task_struct(t: p);
790 j->reclaim_thread = p;
791 wake_up_process(tsk: p);
792 return 0;
793}
794
795static int journal_flush_done(struct journal *j, u64 seq_to_flush,
796 bool *did_work)
797{
798 int ret;
799
800 ret = bch2_journal_error(j);
801 if (ret)
802 return ret;
803
804 mutex_lock(&j->reclaim_lock);
805
806 if (journal_flush_pins(j, seq_to_flush,
807 allowed_below_seq: (1U << JOURNAL_PIN_key_cache)|
808 (1U << JOURNAL_PIN_other), allowed_above_seq: 0, min_any: 0, min_key_cache: 0) ||
809 journal_flush_pins(j, seq_to_flush,
810 allowed_below_seq: (1U << JOURNAL_PIN_btree), allowed_above_seq: 0, min_any: 0, min_key_cache: 0))
811 *did_work = true;
812
813 if (seq_to_flush > journal_cur_seq(j))
814 bch2_journal_entry_close(j);
815
816 spin_lock(lock: &j->lock);
817 /*
818 * If journal replay hasn't completed, the unreplayed journal entries
819 * hold refs on their corresponding sequence numbers
820 */
821 ret = !test_bit(JOURNAL_REPLAY_DONE, &j->flags) ||
822 journal_last_seq(j) > seq_to_flush ||
823 !fifo_used(&j->pin);
824
825 spin_unlock(lock: &j->lock);
826 mutex_unlock(lock: &j->reclaim_lock);
827
828 return ret;
829}
830
831bool bch2_journal_flush_pins(struct journal *j, u64 seq_to_flush)
832{
833 /* time_stats this */
834 bool did_work = false;
835
836 if (!test_bit(JOURNAL_STARTED, &j->flags))
837 return false;
838
839 closure_wait_event(&j->async_wait,
840 journal_flush_done(j, seq_to_flush, &did_work));
841
842 return did_work;
843}
844
845int bch2_journal_flush_device_pins(struct journal *j, int dev_idx)
846{
847 struct bch_fs *c = container_of(j, struct bch_fs, journal);
848 struct journal_entry_pin_list *p;
849 u64 iter, seq = 0;
850 int ret = 0;
851
852 spin_lock(lock: &j->lock);
853 fifo_for_each_entry_ptr(p, &j->pin, iter)
854 if (dev_idx >= 0
855 ? bch2_dev_list_has_dev(devs: p->devs, dev: dev_idx)
856 : p->devs.nr < c->opts.metadata_replicas)
857 seq = iter;
858 spin_unlock(lock: &j->lock);
859
860 bch2_journal_flush_pins(j, seq_to_flush: seq);
861
862 ret = bch2_journal_error(j);
863 if (ret)
864 return ret;
865
866 mutex_lock(&c->replicas_gc_lock);
867 bch2_replicas_gc_start(c, 1 << BCH_DATA_journal);
868
869 /*
870 * Now that we've populated replicas_gc, write to the journal to mark
871 * active journal devices. This handles the case where the journal might
872 * be empty. Otherwise we could clear all journal replicas and
873 * temporarily put the fs into an unrecoverable state. Journal recovery
874 * expects to find devices marked for journal data on unclean mount.
875 */
876 ret = bch2_journal_meta(&c->journal);
877 if (ret)
878 goto err;
879
880 seq = 0;
881 spin_lock(lock: &j->lock);
882 while (!ret) {
883 struct bch_replicas_padded replicas;
884
885 seq = max(seq, journal_last_seq(j));
886 if (seq >= j->pin.back)
887 break;
888 bch2_devlist_to_replicas(&replicas.e, BCH_DATA_journal,
889 journal_seq_pin(j, seq)->devs);
890 seq++;
891
892 if (replicas.e.nr_devs) {
893 spin_unlock(lock: &j->lock);
894 ret = bch2_mark_replicas(c, &replicas.e);
895 spin_lock(lock: &j->lock);
896 }
897 }
898 spin_unlock(lock: &j->lock);
899err:
900 ret = bch2_replicas_gc_end(c, ret);
901 mutex_unlock(lock: &c->replicas_gc_lock);
902
903 return ret;
904}
905

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