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(&c->times[BCH_TIME_blocked_journal_low_on_space], low_on_space) ||
66	    track_event_change(&c->times[BCH_TIME_blocked_journal_low_on_pin], low_on_pin) ||
67	    track_event_change(&c->times[BCH_TIME_blocked_write_buffer_full], low_on_wb))
68		trace_and_count(c, journal_full, c);
69
70	mod_bit(JOURNAL_SPACE_LOW, &j->flags, 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, 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(JOURNAL_MAY_SKIP_FLUSH, &j->flags);
229	else
230		clear_bit(JOURNAL_MAY_SKIP_FLUSH, &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(&j->lock);
248	ret = ja->discard_idx != ja->dirty_idx_ondisk;
249	spin_unlock(&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(ca->disk_sb.bdev))
271				blkdev_issue_discard(ca->disk_sb.bdev,
272					bucket_to_sector(ca,
273						ja->buckets[ja->discard_idx]),
274					ca->mi.bucket_size, GFP_NOFS);
275
276			spin_lock(&j->lock);
277			ja->discard_idx = (ja->discard_idx + 1) % ja->nr;
278
279			bch2_journal_space_available(j);
280			spin_unlock(&j->lock);
281		}
282	}
283
284	mutex_unlock(&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(&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(&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(&j->lock);
324		bch2_journal_reclaim_fast(j);
325		spin_unlock(&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, pin->seq);
341	pin->seq = 0;
342	list_del_init(&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(&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(&j->lock);
356	if (__journal_pin_drop(j, pin))
357		bch2_journal_reclaim_fast(j);
358	spin_unlock(&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(&pin_list->count);
386	pin->seq	= seq;
387	pin->flush	= flush_fn;
388	list_add(&pin->list, &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(&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(&j->lock);
408		return;
409	}
410
411	bool reclaim = __journal_pin_drop(j, dst);
412
413	bch2_journal_pin_set_locked(j, seq, dst, flush_fn, journal_pin_type(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(&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(&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, journal_pin_type(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(&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(&j->lock);
535		pin = journal_get_next_pin(j, seq_to_flush, allowed_below, allowed_above, &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(&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(&j->lock);
556		/* Pin might have been dropped or rearmed: */
557		if (likely(!err && !j->flush_in_progress_dropped))
558			list_move(&pin->list, &journal_seq_pin(j, seq)->flushed);
559		j->flush_in_progress = NULL;
560		j->flush_in_progress_dropped = false;
561		spin_unlock(&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(&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(&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(&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						~0, 0,
687						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, true, 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, false, kicked);
728		mutex_unlock(&j->reclaim_lock);
729
730		now = jiffies;
731		delay = msecs_to_jiffies(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(&j->lock);
745			journal_empty = fifo_empty(&j->pin);
746			spin_unlock(&j->lock);
747
748			if (journal_empty)
749				schedule();
750			else if (time_after(j->next_reclaim, jiffies))
751				schedule_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(p);
769		put_task_struct(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(p);
785	bch_err_msg(c, ret, "creating journal reclaim thread");
786	if (ret)
787		return ret;
788
789	get_task_struct(p);
790	j->reclaim_thread = p;
791	wake_up_process(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			       (1U << JOURNAL_PIN_key_cache)|
808			       (1U << JOURNAL_PIN_other), 0, 0, 0) ||
809	    journal_flush_pins(j, seq_to_flush,
810			       (1U << JOURNAL_PIN_btree), 0, 0, 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(&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(&j->lock);
826	mutex_unlock(&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(&j->lock);
853	fifo_for_each_entry_ptr(p, &j->pin, iter)
854		if (dev_idx >= 0
855		    ? bch2_dev_list_has_dev(p->devs, dev_idx)
856		    : p->devs.nr < c->opts.metadata_replicas)
857			seq = iter;
858	spin_unlock(&j->lock);
859
860	bch2_journal_flush_pins(j, 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(&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(&j->lock);
894			ret = bch2_mark_replicas(c, &replicas.e);
895			spin_lock(&j->lock);
896		}
897	}
898	spin_unlock(&j->lock);
899err:
900	ret = bch2_replicas_gc_end(c, ret);
901	mutex_unlock(&c->replicas_gc_lock);
902
903	return ret;
904}
905