Merge tag 'ceph-for-5.11-rc2' of git://github.com/ceph/ceph-client
[linux-2.6-microblaze.git] / drivers / md / bcache / journal.c
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * bcache journalling code, for btree insertions
4  *
5  * Copyright 2012 Google, Inc.
6  */
7
8 #include "bcache.h"
9 #include "btree.h"
10 #include "debug.h"
11 #include "extents.h"
12
13 #include <trace/events/bcache.h>
14
15 /*
16  * Journal replay/recovery:
17  *
18  * This code is all driven from run_cache_set(); we first read the journal
19  * entries, do some other stuff, then we mark all the keys in the journal
20  * entries (same as garbage collection would), then we replay them - reinserting
21  * them into the cache in precisely the same order as they appear in the
22  * journal.
23  *
24  * We only journal keys that go in leaf nodes, which simplifies things quite a
25  * bit.
26  */
27
28 static void journal_read_endio(struct bio *bio)
29 {
30         struct closure *cl = bio->bi_private;
31
32         closure_put(cl);
33 }
34
35 static int journal_read_bucket(struct cache *ca, struct list_head *list,
36                                unsigned int bucket_index)
37 {
38         struct journal_device *ja = &ca->journal;
39         struct bio *bio = &ja->bio;
40
41         struct journal_replay *i;
42         struct jset *j, *data = ca->set->journal.w[0].data;
43         struct closure cl;
44         unsigned int len, left, offset = 0;
45         int ret = 0;
46         sector_t bucket = bucket_to_sector(ca->set, ca->sb.d[bucket_index]);
47
48         closure_init_stack(&cl);
49
50         pr_debug("reading %u\n", bucket_index);
51
52         while (offset < ca->sb.bucket_size) {
53 reread:         left = ca->sb.bucket_size - offset;
54                 len = min_t(unsigned int, left, PAGE_SECTORS << JSET_BITS);
55
56                 bio_reset(bio);
57                 bio->bi_iter.bi_sector  = bucket + offset;
58                 bio_set_dev(bio, ca->bdev);
59                 bio->bi_iter.bi_size    = len << 9;
60
61                 bio->bi_end_io  = journal_read_endio;
62                 bio->bi_private = &cl;
63                 bio_set_op_attrs(bio, REQ_OP_READ, 0);
64                 bch_bio_map(bio, data);
65
66                 closure_bio_submit(ca->set, bio, &cl);
67                 closure_sync(&cl);
68
69                 /* This function could be simpler now since we no longer write
70                  * journal entries that overlap bucket boundaries; this means
71                  * the start of a bucket will always have a valid journal entry
72                  * if it has any journal entries at all.
73                  */
74
75                 j = data;
76                 while (len) {
77                         struct list_head *where;
78                         size_t blocks, bytes = set_bytes(j);
79
80                         if (j->magic != jset_magic(&ca->sb)) {
81                                 pr_debug("%u: bad magic\n", bucket_index);
82                                 return ret;
83                         }
84
85                         if (bytes > left << 9 ||
86                             bytes > PAGE_SIZE << JSET_BITS) {
87                                 pr_info("%u: too big, %zu bytes, offset %u\n",
88                                         bucket_index, bytes, offset);
89                                 return ret;
90                         }
91
92                         if (bytes > len << 9)
93                                 goto reread;
94
95                         if (j->csum != csum_set(j)) {
96                                 pr_info("%u: bad csum, %zu bytes, offset %u\n",
97                                         bucket_index, bytes, offset);
98                                 return ret;
99                         }
100
101                         blocks = set_blocks(j, block_bytes(ca));
102
103                         /*
104                          * Nodes in 'list' are in linear increasing order of
105                          * i->j.seq, the node on head has the smallest (oldest)
106                          * journal seq, the node on tail has the biggest
107                          * (latest) journal seq.
108                          */
109
110                         /*
111                          * Check from the oldest jset for last_seq. If
112                          * i->j.seq < j->last_seq, it means the oldest jset
113                          * in list is expired and useless, remove it from
114                          * this list. Otherwise, j is a condidate jset for
115                          * further following checks.
116                          */
117                         while (!list_empty(list)) {
118                                 i = list_first_entry(list,
119                                         struct journal_replay, list);
120                                 if (i->j.seq >= j->last_seq)
121                                         break;
122                                 list_del(&i->list);
123                                 kfree(i);
124                         }
125
126                         /* iterate list in reverse order (from latest jset) */
127                         list_for_each_entry_reverse(i, list, list) {
128                                 if (j->seq == i->j.seq)
129                                         goto next_set;
130
131                                 /*
132                                  * if j->seq is less than any i->j.last_seq
133                                  * in list, j is an expired and useless jset.
134                                  */
135                                 if (j->seq < i->j.last_seq)
136                                         goto next_set;
137
138                                 /*
139                                  * 'where' points to first jset in list which
140                                  * is elder then j.
141                                  */
142                                 if (j->seq > i->j.seq) {
143                                         where = &i->list;
144                                         goto add;
145                                 }
146                         }
147
148                         where = list;
149 add:
150                         i = kmalloc(offsetof(struct journal_replay, j) +
151                                     bytes, GFP_KERNEL);
152                         if (!i)
153                                 return -ENOMEM;
154                         memcpy(&i->j, j, bytes);
155                         /* Add to the location after 'where' points to */
156                         list_add(&i->list, where);
157                         ret = 1;
158
159                         if (j->seq > ja->seq[bucket_index])
160                                 ja->seq[bucket_index] = j->seq;
161 next_set:
162                         offset  += blocks * ca->sb.block_size;
163                         len     -= blocks * ca->sb.block_size;
164                         j = ((void *) j) + blocks * block_bytes(ca);
165                 }
166         }
167
168         return ret;
169 }
170
171 int bch_journal_read(struct cache_set *c, struct list_head *list)
172 {
173 #define read_bucket(b)                                                  \
174         ({                                                              \
175                 ret = journal_read_bucket(ca, list, b);                 \
176                 __set_bit(b, bitmap);                                   \
177                 if (ret < 0)                                            \
178                         return ret;                                     \
179                 ret;                                                    \
180         })
181
182         struct cache *ca = c->cache;
183         int ret = 0;
184         struct journal_device *ja = &ca->journal;
185         DECLARE_BITMAP(bitmap, SB_JOURNAL_BUCKETS);
186         unsigned int i, l, r, m;
187         uint64_t seq;
188
189         bitmap_zero(bitmap, SB_JOURNAL_BUCKETS);
190         pr_debug("%u journal buckets\n", ca->sb.njournal_buckets);
191
192         /*
193          * Read journal buckets ordered by golden ratio hash to quickly
194          * find a sequence of buckets with valid journal entries
195          */
196         for (i = 0; i < ca->sb.njournal_buckets; i++) {
197                 /*
198                  * We must try the index l with ZERO first for
199                  * correctness due to the scenario that the journal
200                  * bucket is circular buffer which might have wrapped
201                  */
202                 l = (i * 2654435769U) % ca->sb.njournal_buckets;
203
204                 if (test_bit(l, bitmap))
205                         break;
206
207                 if (read_bucket(l))
208                         goto bsearch;
209         }
210
211         /*
212          * If that fails, check all the buckets we haven't checked
213          * already
214          */
215         pr_debug("falling back to linear search\n");
216
217         for_each_clear_bit(l, bitmap, ca->sb.njournal_buckets)
218                 if (read_bucket(l))
219                         goto bsearch;
220
221         /* no journal entries on this device? */
222         if (l == ca->sb.njournal_buckets)
223                 goto out;
224 bsearch:
225         BUG_ON(list_empty(list));
226
227         /* Binary search */
228         m = l;
229         r = find_next_bit(bitmap, ca->sb.njournal_buckets, l + 1);
230         pr_debug("starting binary search, l %u r %u\n", l, r);
231
232         while (l + 1 < r) {
233                 seq = list_entry(list->prev, struct journal_replay,
234                                  list)->j.seq;
235
236                 m = (l + r) >> 1;
237                 read_bucket(m);
238
239                 if (seq != list_entry(list->prev, struct journal_replay,
240                                       list)->j.seq)
241                         l = m;
242                 else
243                         r = m;
244         }
245
246         /*
247          * Read buckets in reverse order until we stop finding more
248          * journal entries
249          */
250         pr_debug("finishing up: m %u njournal_buckets %u\n",
251                  m, ca->sb.njournal_buckets);
252         l = m;
253
254         while (1) {
255                 if (!l--)
256                         l = ca->sb.njournal_buckets - 1;
257
258                 if (l == m)
259                         break;
260
261                 if (test_bit(l, bitmap))
262                         continue;
263
264                 if (!read_bucket(l))
265                         break;
266         }
267
268         seq = 0;
269
270         for (i = 0; i < ca->sb.njournal_buckets; i++)
271                 if (ja->seq[i] > seq) {
272                         seq = ja->seq[i];
273                         /*
274                          * When journal_reclaim() goes to allocate for
275                          * the first time, it'll use the bucket after
276                          * ja->cur_idx
277                          */
278                         ja->cur_idx = i;
279                         ja->last_idx = ja->discard_idx = (i + 1) %
280                                 ca->sb.njournal_buckets;
281
282                 }
283
284 out:
285         if (!list_empty(list))
286                 c->journal.seq = list_entry(list->prev,
287                                             struct journal_replay,
288                                             list)->j.seq;
289
290         return 0;
291 #undef read_bucket
292 }
293
294 void bch_journal_mark(struct cache_set *c, struct list_head *list)
295 {
296         atomic_t p = { 0 };
297         struct bkey *k;
298         struct journal_replay *i;
299         struct journal *j = &c->journal;
300         uint64_t last = j->seq;
301
302         /*
303          * journal.pin should never fill up - we never write a journal
304          * entry when it would fill up. But if for some reason it does, we
305          * iterate over the list in reverse order so that we can just skip that
306          * refcount instead of bugging.
307          */
308
309         list_for_each_entry_reverse(i, list, list) {
310                 BUG_ON(last < i->j.seq);
311                 i->pin = NULL;
312
313                 while (last-- != i->j.seq)
314                         if (fifo_free(&j->pin) > 1) {
315                                 fifo_push_front(&j->pin, p);
316                                 atomic_set(&fifo_front(&j->pin), 0);
317                         }
318
319                 if (fifo_free(&j->pin) > 1) {
320                         fifo_push_front(&j->pin, p);
321                         i->pin = &fifo_front(&j->pin);
322                         atomic_set(i->pin, 1);
323                 }
324
325                 for (k = i->j.start;
326                      k < bset_bkey_last(&i->j);
327                      k = bkey_next(k))
328                         if (!__bch_extent_invalid(c, k)) {
329                                 unsigned int j;
330
331                                 for (j = 0; j < KEY_PTRS(k); j++)
332                                         if (ptr_available(c, k, j))
333                                                 atomic_inc(&PTR_BUCKET(c, k, j)->pin);
334
335                                 bch_initial_mark_key(c, 0, k);
336                         }
337         }
338 }
339
340 static bool is_discard_enabled(struct cache_set *s)
341 {
342         struct cache *ca = s->cache;
343
344         if (ca->discard)
345                 return true;
346
347         return false;
348 }
349
350 int bch_journal_replay(struct cache_set *s, struct list_head *list)
351 {
352         int ret = 0, keys = 0, entries = 0;
353         struct bkey *k;
354         struct journal_replay *i =
355                 list_entry(list->prev, struct journal_replay, list);
356
357         uint64_t start = i->j.last_seq, end = i->j.seq, n = start;
358         struct keylist keylist;
359
360         list_for_each_entry(i, list, list) {
361                 BUG_ON(i->pin && atomic_read(i->pin) != 1);
362
363                 if (n != i->j.seq) {
364                         if (n == start && is_discard_enabled(s))
365                                 pr_info("journal entries %llu-%llu may be discarded! (replaying %llu-%llu)\n",
366                                         n, i->j.seq - 1, start, end);
367                         else {
368                                 pr_err("journal entries %llu-%llu missing! (replaying %llu-%llu)\n",
369                                         n, i->j.seq - 1, start, end);
370                                 ret = -EIO;
371                                 goto err;
372                         }
373                 }
374
375                 for (k = i->j.start;
376                      k < bset_bkey_last(&i->j);
377                      k = bkey_next(k)) {
378                         trace_bcache_journal_replay_key(k);
379
380                         bch_keylist_init_single(&keylist, k);
381
382                         ret = bch_btree_insert(s, &keylist, i->pin, NULL);
383                         if (ret)
384                                 goto err;
385
386                         BUG_ON(!bch_keylist_empty(&keylist));
387                         keys++;
388
389                         cond_resched();
390                 }
391
392                 if (i->pin)
393                         atomic_dec(i->pin);
394                 n = i->j.seq + 1;
395                 entries++;
396         }
397
398         pr_info("journal replay done, %i keys in %i entries, seq %llu\n",
399                 keys, entries, end);
400 err:
401         while (!list_empty(list)) {
402                 i = list_first_entry(list, struct journal_replay, list);
403                 list_del(&i->list);
404                 kfree(i);
405         }
406
407         return ret;
408 }
409
410 /* Journalling */
411
412 static void btree_flush_write(struct cache_set *c)
413 {
414         struct btree *b, *t, *btree_nodes[BTREE_FLUSH_NR];
415         unsigned int i, nr;
416         int ref_nr;
417         atomic_t *fifo_front_p, *now_fifo_front_p;
418         size_t mask;
419
420         if (c->journal.btree_flushing)
421                 return;
422
423         spin_lock(&c->journal.flush_write_lock);
424         if (c->journal.btree_flushing) {
425                 spin_unlock(&c->journal.flush_write_lock);
426                 return;
427         }
428         c->journal.btree_flushing = true;
429         spin_unlock(&c->journal.flush_write_lock);
430
431         /* get the oldest journal entry and check its refcount */
432         spin_lock(&c->journal.lock);
433         fifo_front_p = &fifo_front(&c->journal.pin);
434         ref_nr = atomic_read(fifo_front_p);
435         if (ref_nr <= 0) {
436                 /*
437                  * do nothing if no btree node references
438                  * the oldest journal entry
439                  */
440                 spin_unlock(&c->journal.lock);
441                 goto out;
442         }
443         spin_unlock(&c->journal.lock);
444
445         mask = c->journal.pin.mask;
446         nr = 0;
447         atomic_long_inc(&c->flush_write);
448         memset(btree_nodes, 0, sizeof(btree_nodes));
449
450         mutex_lock(&c->bucket_lock);
451         list_for_each_entry_safe_reverse(b, t, &c->btree_cache, list) {
452                 /*
453                  * It is safe to get now_fifo_front_p without holding
454                  * c->journal.lock here, because we don't need to know
455                  * the exactly accurate value, just check whether the
456                  * front pointer of c->journal.pin is changed.
457                  */
458                 now_fifo_front_p = &fifo_front(&c->journal.pin);
459                 /*
460                  * If the oldest journal entry is reclaimed and front
461                  * pointer of c->journal.pin changes, it is unnecessary
462                  * to scan c->btree_cache anymore, just quit the loop and
463                  * flush out what we have already.
464                  */
465                 if (now_fifo_front_p != fifo_front_p)
466                         break;
467                 /*
468                  * quit this loop if all matching btree nodes are
469                  * scanned and record in btree_nodes[] already.
470                  */
471                 ref_nr = atomic_read(fifo_front_p);
472                 if (nr >= ref_nr)
473                         break;
474
475                 if (btree_node_journal_flush(b))
476                         pr_err("BUG: flush_write bit should not be set here!\n");
477
478                 mutex_lock(&b->write_lock);
479
480                 if (!btree_node_dirty(b)) {
481                         mutex_unlock(&b->write_lock);
482                         continue;
483                 }
484
485                 if (!btree_current_write(b)->journal) {
486                         mutex_unlock(&b->write_lock);
487                         continue;
488                 }
489
490                 /*
491                  * Only select the btree node which exactly references
492                  * the oldest journal entry.
493                  *
494                  * If the journal entry pointed by fifo_front_p is
495                  * reclaimed in parallel, don't worry:
496                  * - the list_for_each_xxx loop will quit when checking
497                  *   next now_fifo_front_p.
498                  * - If there are matched nodes recorded in btree_nodes[],
499                  *   they are clean now (this is why and how the oldest
500                  *   journal entry can be reclaimed). These selected nodes
501                  *   will be ignored and skipped in the folowing for-loop.
502                  */
503                 if (((btree_current_write(b)->journal - fifo_front_p) &
504                      mask) != 0) {
505                         mutex_unlock(&b->write_lock);
506                         continue;
507                 }
508
509                 set_btree_node_journal_flush(b);
510
511                 mutex_unlock(&b->write_lock);
512
513                 btree_nodes[nr++] = b;
514                 /*
515                  * To avoid holding c->bucket_lock too long time,
516                  * only scan for BTREE_FLUSH_NR matched btree nodes
517                  * at most. If there are more btree nodes reference
518                  * the oldest journal entry, try to flush them next
519                  * time when btree_flush_write() is called.
520                  */
521                 if (nr == BTREE_FLUSH_NR)
522                         break;
523         }
524         mutex_unlock(&c->bucket_lock);
525
526         for (i = 0; i < nr; i++) {
527                 b = btree_nodes[i];
528                 if (!b) {
529                         pr_err("BUG: btree_nodes[%d] is NULL\n", i);
530                         continue;
531                 }
532
533                 /* safe to check without holding b->write_lock */
534                 if (!btree_node_journal_flush(b)) {
535                         pr_err("BUG: bnode %p: journal_flush bit cleaned\n", b);
536                         continue;
537                 }
538
539                 mutex_lock(&b->write_lock);
540                 if (!btree_current_write(b)->journal) {
541                         clear_bit(BTREE_NODE_journal_flush, &b->flags);
542                         mutex_unlock(&b->write_lock);
543                         pr_debug("bnode %p: written by others\n", b);
544                         continue;
545                 }
546
547                 if (!btree_node_dirty(b)) {
548                         clear_bit(BTREE_NODE_journal_flush, &b->flags);
549                         mutex_unlock(&b->write_lock);
550                         pr_debug("bnode %p: dirty bit cleaned by others\n", b);
551                         continue;
552                 }
553
554                 __bch_btree_node_write(b, NULL);
555                 clear_bit(BTREE_NODE_journal_flush, &b->flags);
556                 mutex_unlock(&b->write_lock);
557         }
558
559 out:
560         spin_lock(&c->journal.flush_write_lock);
561         c->journal.btree_flushing = false;
562         spin_unlock(&c->journal.flush_write_lock);
563 }
564
565 #define last_seq(j)     ((j)->seq - fifo_used(&(j)->pin) + 1)
566
567 static void journal_discard_endio(struct bio *bio)
568 {
569         struct journal_device *ja =
570                 container_of(bio, struct journal_device, discard_bio);
571         struct cache *ca = container_of(ja, struct cache, journal);
572
573         atomic_set(&ja->discard_in_flight, DISCARD_DONE);
574
575         closure_wake_up(&ca->set->journal.wait);
576         closure_put(&ca->set->cl);
577 }
578
579 static void journal_discard_work(struct work_struct *work)
580 {
581         struct journal_device *ja =
582                 container_of(work, struct journal_device, discard_work);
583
584         submit_bio(&ja->discard_bio);
585 }
586
587 static void do_journal_discard(struct cache *ca)
588 {
589         struct journal_device *ja = &ca->journal;
590         struct bio *bio = &ja->discard_bio;
591
592         if (!ca->discard) {
593                 ja->discard_idx = ja->last_idx;
594                 return;
595         }
596
597         switch (atomic_read(&ja->discard_in_flight)) {
598         case DISCARD_IN_FLIGHT:
599                 return;
600
601         case DISCARD_DONE:
602                 ja->discard_idx = (ja->discard_idx + 1) %
603                         ca->sb.njournal_buckets;
604
605                 atomic_set(&ja->discard_in_flight, DISCARD_READY);
606                 fallthrough;
607
608         case DISCARD_READY:
609                 if (ja->discard_idx == ja->last_idx)
610                         return;
611
612                 atomic_set(&ja->discard_in_flight, DISCARD_IN_FLIGHT);
613
614                 bio_init(bio, bio->bi_inline_vecs, 1);
615                 bio_set_op_attrs(bio, REQ_OP_DISCARD, 0);
616                 bio->bi_iter.bi_sector  = bucket_to_sector(ca->set,
617                                                 ca->sb.d[ja->discard_idx]);
618                 bio_set_dev(bio, ca->bdev);
619                 bio->bi_iter.bi_size    = bucket_bytes(ca);
620                 bio->bi_end_io          = journal_discard_endio;
621
622                 closure_get(&ca->set->cl);
623                 INIT_WORK(&ja->discard_work, journal_discard_work);
624                 queue_work(bch_journal_wq, &ja->discard_work);
625         }
626 }
627
628 static void journal_reclaim(struct cache_set *c)
629 {
630         struct bkey *k = &c->journal.key;
631         struct cache *ca = c->cache;
632         uint64_t last_seq;
633         unsigned int next;
634         struct journal_device *ja = &ca->journal;
635         atomic_t p __maybe_unused;
636
637         atomic_long_inc(&c->reclaim);
638
639         while (!atomic_read(&fifo_front(&c->journal.pin)))
640                 fifo_pop(&c->journal.pin, p);
641
642         last_seq = last_seq(&c->journal);
643
644         /* Update last_idx */
645
646         while (ja->last_idx != ja->cur_idx &&
647                ja->seq[ja->last_idx] < last_seq)
648                 ja->last_idx = (ja->last_idx + 1) %
649                         ca->sb.njournal_buckets;
650
651         do_journal_discard(ca);
652
653         if (c->journal.blocks_free)
654                 goto out;
655
656         next = (ja->cur_idx + 1) % ca->sb.njournal_buckets;
657         /* No space available on this device */
658         if (next == ja->discard_idx)
659                 goto out;
660
661         ja->cur_idx = next;
662         k->ptr[0] = MAKE_PTR(0,
663                              bucket_to_sector(c, ca->sb.d[ja->cur_idx]),
664                              ca->sb.nr_this_dev);
665         atomic_long_inc(&c->reclaimed_journal_buckets);
666
667         bkey_init(k);
668         SET_KEY_PTRS(k, 1);
669         c->journal.blocks_free = ca->sb.bucket_size >> c->block_bits;
670
671 out:
672         if (!journal_full(&c->journal))
673                 __closure_wake_up(&c->journal.wait);
674 }
675
676 void bch_journal_next(struct journal *j)
677 {
678         atomic_t p = { 1 };
679
680         j->cur = (j->cur == j->w)
681                 ? &j->w[1]
682                 : &j->w[0];
683
684         /*
685          * The fifo_push() needs to happen at the same time as j->seq is
686          * incremented for last_seq() to be calculated correctly
687          */
688         BUG_ON(!fifo_push(&j->pin, p));
689         atomic_set(&fifo_back(&j->pin), 1);
690
691         j->cur->data->seq       = ++j->seq;
692         j->cur->dirty           = false;
693         j->cur->need_write      = false;
694         j->cur->data->keys      = 0;
695
696         if (fifo_full(&j->pin))
697                 pr_debug("journal_pin full (%zu)\n", fifo_used(&j->pin));
698 }
699
700 static void journal_write_endio(struct bio *bio)
701 {
702         struct journal_write *w = bio->bi_private;
703
704         cache_set_err_on(bio->bi_status, w->c, "journal io error");
705         closure_put(&w->c->journal.io);
706 }
707
708 static void journal_write(struct closure *cl);
709
710 static void journal_write_done(struct closure *cl)
711 {
712         struct journal *j = container_of(cl, struct journal, io);
713         struct journal_write *w = (j->cur == j->w)
714                 ? &j->w[1]
715                 : &j->w[0];
716
717         __closure_wake_up(&w->wait);
718         continue_at_nobarrier(cl, journal_write, bch_journal_wq);
719 }
720
721 static void journal_write_unlock(struct closure *cl)
722         __releases(&c->journal.lock)
723 {
724         struct cache_set *c = container_of(cl, struct cache_set, journal.io);
725
726         c->journal.io_in_flight = 0;
727         spin_unlock(&c->journal.lock);
728 }
729
730 static void journal_write_unlocked(struct closure *cl)
731         __releases(c->journal.lock)
732 {
733         struct cache_set *c = container_of(cl, struct cache_set, journal.io);
734         struct cache *ca = c->cache;
735         struct journal_write *w = c->journal.cur;
736         struct bkey *k = &c->journal.key;
737         unsigned int i, sectors = set_blocks(w->data, block_bytes(ca)) *
738                 ca->sb.block_size;
739
740         struct bio *bio;
741         struct bio_list list;
742
743         bio_list_init(&list);
744
745         if (!w->need_write) {
746                 closure_return_with_destructor(cl, journal_write_unlock);
747                 return;
748         } else if (journal_full(&c->journal)) {
749                 journal_reclaim(c);
750                 spin_unlock(&c->journal.lock);
751
752                 btree_flush_write(c);
753                 continue_at(cl, journal_write, bch_journal_wq);
754                 return;
755         }
756
757         c->journal.blocks_free -= set_blocks(w->data, block_bytes(ca));
758
759         w->data->btree_level = c->root->level;
760
761         bkey_copy(&w->data->btree_root, &c->root->key);
762         bkey_copy(&w->data->uuid_bucket, &c->uuid_bucket);
763
764         w->data->prio_bucket[ca->sb.nr_this_dev] = ca->prio_buckets[0];
765         w->data->magic          = jset_magic(&ca->sb);
766         w->data->version        = BCACHE_JSET_VERSION;
767         w->data->last_seq       = last_seq(&c->journal);
768         w->data->csum           = csum_set(w->data);
769
770         for (i = 0; i < KEY_PTRS(k); i++) {
771                 ca = PTR_CACHE(c, k, i);
772                 bio = &ca->journal.bio;
773
774                 atomic_long_add(sectors, &ca->meta_sectors_written);
775
776                 bio_reset(bio);
777                 bio->bi_iter.bi_sector  = PTR_OFFSET(k, i);
778                 bio_set_dev(bio, ca->bdev);
779                 bio->bi_iter.bi_size = sectors << 9;
780
781                 bio->bi_end_io  = journal_write_endio;
782                 bio->bi_private = w;
783                 bio_set_op_attrs(bio, REQ_OP_WRITE,
784                                  REQ_SYNC|REQ_META|REQ_PREFLUSH|REQ_FUA);
785                 bch_bio_map(bio, w->data);
786
787                 trace_bcache_journal_write(bio, w->data->keys);
788                 bio_list_add(&list, bio);
789
790                 SET_PTR_OFFSET(k, i, PTR_OFFSET(k, i) + sectors);
791
792                 ca->journal.seq[ca->journal.cur_idx] = w->data->seq;
793         }
794
795         /* If KEY_PTRS(k) == 0, this jset gets lost in air */
796         BUG_ON(i == 0);
797
798         atomic_dec_bug(&fifo_back(&c->journal.pin));
799         bch_journal_next(&c->journal);
800         journal_reclaim(c);
801
802         spin_unlock(&c->journal.lock);
803
804         while ((bio = bio_list_pop(&list)))
805                 closure_bio_submit(c, bio, cl);
806
807         continue_at(cl, journal_write_done, NULL);
808 }
809
810 static void journal_write(struct closure *cl)
811 {
812         struct cache_set *c = container_of(cl, struct cache_set, journal.io);
813
814         spin_lock(&c->journal.lock);
815         journal_write_unlocked(cl);
816 }
817
818 static void journal_try_write(struct cache_set *c)
819         __releases(c->journal.lock)
820 {
821         struct closure *cl = &c->journal.io;
822         struct journal_write *w = c->journal.cur;
823
824         w->need_write = true;
825
826         if (!c->journal.io_in_flight) {
827                 c->journal.io_in_flight = 1;
828                 closure_call(cl, journal_write_unlocked, NULL, &c->cl);
829         } else {
830                 spin_unlock(&c->journal.lock);
831         }
832 }
833
834 static struct journal_write *journal_wait_for_write(struct cache_set *c,
835                                                     unsigned int nkeys)
836         __acquires(&c->journal.lock)
837 {
838         size_t sectors;
839         struct closure cl;
840         bool wait = false;
841         struct cache *ca = c->cache;
842
843         closure_init_stack(&cl);
844
845         spin_lock(&c->journal.lock);
846
847         while (1) {
848                 struct journal_write *w = c->journal.cur;
849
850                 sectors = __set_blocks(w->data, w->data->keys + nkeys,
851                                        block_bytes(ca)) * ca->sb.block_size;
852
853                 if (sectors <= min_t(size_t,
854                                      c->journal.blocks_free * ca->sb.block_size,
855                                      PAGE_SECTORS << JSET_BITS))
856                         return w;
857
858                 if (wait)
859                         closure_wait(&c->journal.wait, &cl);
860
861                 if (!journal_full(&c->journal)) {
862                         if (wait)
863                                 trace_bcache_journal_entry_full(c);
864
865                         /*
866                          * XXX: If we were inserting so many keys that they
867                          * won't fit in an _empty_ journal write, we'll
868                          * deadlock. For now, handle this in
869                          * bch_keylist_realloc() - but something to think about.
870                          */
871                         BUG_ON(!w->data->keys);
872
873                         journal_try_write(c); /* unlocks */
874                 } else {
875                         if (wait)
876                                 trace_bcache_journal_full(c);
877
878                         journal_reclaim(c);
879                         spin_unlock(&c->journal.lock);
880
881                         btree_flush_write(c);
882                 }
883
884                 closure_sync(&cl);
885                 spin_lock(&c->journal.lock);
886                 wait = true;
887         }
888 }
889
890 static void journal_write_work(struct work_struct *work)
891 {
892         struct cache_set *c = container_of(to_delayed_work(work),
893                                            struct cache_set,
894                                            journal.work);
895         spin_lock(&c->journal.lock);
896         if (c->journal.cur->dirty)
897                 journal_try_write(c);
898         else
899                 spin_unlock(&c->journal.lock);
900 }
901
902 /*
903  * Entry point to the journalling code - bio_insert() and btree_invalidate()
904  * pass bch_journal() a list of keys to be journalled, and then
905  * bch_journal() hands those same keys off to btree_insert_async()
906  */
907
908 atomic_t *bch_journal(struct cache_set *c,
909                       struct keylist *keys,
910                       struct closure *parent)
911 {
912         struct journal_write *w;
913         atomic_t *ret;
914
915         /* No journaling if CACHE_SET_IO_DISABLE set already */
916         if (unlikely(test_bit(CACHE_SET_IO_DISABLE, &c->flags)))
917                 return NULL;
918
919         if (!CACHE_SYNC(&c->cache->sb))
920                 return NULL;
921
922         w = journal_wait_for_write(c, bch_keylist_nkeys(keys));
923
924         memcpy(bset_bkey_last(w->data), keys->keys, bch_keylist_bytes(keys));
925         w->data->keys += bch_keylist_nkeys(keys);
926
927         ret = &fifo_back(&c->journal.pin);
928         atomic_inc(ret);
929
930         if (parent) {
931                 closure_wait(&w->wait, parent);
932                 journal_try_write(c);
933         } else if (!w->dirty) {
934                 w->dirty = true;
935                 schedule_delayed_work(&c->journal.work,
936                                       msecs_to_jiffies(c->journal_delay_ms));
937                 spin_unlock(&c->journal.lock);
938         } else {
939                 spin_unlock(&c->journal.lock);
940         }
941
942
943         return ret;
944 }
945
946 void bch_journal_meta(struct cache_set *c, struct closure *cl)
947 {
948         struct keylist keys;
949         atomic_t *ref;
950
951         bch_keylist_init(&keys);
952
953         ref = bch_journal(c, &keys, cl);
954         if (ref)
955                 atomic_dec_bug(ref);
956 }
957
958 void bch_journal_free(struct cache_set *c)
959 {
960         free_pages((unsigned long) c->journal.w[1].data, JSET_BITS);
961         free_pages((unsigned long) c->journal.w[0].data, JSET_BITS);
962         free_fifo(&c->journal.pin);
963 }
964
965 int bch_journal_alloc(struct cache_set *c)
966 {
967         struct journal *j = &c->journal;
968
969         spin_lock_init(&j->lock);
970         spin_lock_init(&j->flush_write_lock);
971         INIT_DELAYED_WORK(&j->work, journal_write_work);
972
973         c->journal_delay_ms = 100;
974
975         j->w[0].c = c;
976         j->w[1].c = c;
977
978         if (!(init_fifo(&j->pin, JOURNAL_PIN, GFP_KERNEL)) ||
979             !(j->w[0].data = (void *) __get_free_pages(GFP_KERNEL|__GFP_COMP, JSET_BITS)) ||
980             !(j->w[1].data = (void *) __get_free_pages(GFP_KERNEL|__GFP_COMP, JSET_BITS)))
981                 return -ENOMEM;
982
983         return 0;
984 }