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         closure_put(cl);
  32 }
  33
  34 static int journal_read_bucket(struct cache *ca, struct list_head *list,
  35                                unsigned bucket_index)
  36 {
  37         struct journal_device *ja = &ca->journal;
  38         struct bio *bio = &ja->bio;
  39
  40         struct journal_replay *i;
  41         struct jset *j, *data = ca->set->journal.w[0].data;
  42         struct closure cl;
  43         unsigned len, left, offset = 0;
  44         int ret = 0;
  45         sector_t bucket = bucket_to_sector(ca->set, ca->sb.d[bucket_index]);
  46
  47         closure_init_stack(&cl);
  48
  49         pr_debug("reading %u", bucket_index);
  50
  51         while (offset < ca->sb.bucket_size) {
  52 reread:         left = ca->sb.bucket_size - offset;
  53                 len = min_t(unsigned, left, PAGE_SECTORS << JSET_BITS);
  54
  55                 bio_reset(bio);
  56                 bio->bi_iter.bi_sector  = bucket + offset;
  57                 bio_set_dev(bio, ca->bdev);
  58                 bio->bi_iter.bi_size    = len << 9;
  59
  60                 bio->bi_end_io  = journal_read_endio;
  61                 bio->bi_private = &cl;
  62                 bio_set_op_attrs(bio, REQ_OP_READ, 0);
  63                 bch_bio_map(bio, data);
  64
  65                 closure_bio_submit(bio, &cl);
  66                 closure_sync(&cl);
  67
  68                 /* This function could be simpler now since we no longer write
  69                  * journal entries that overlap bucket boundaries; this means
  70                  * the start of a bucket will always have a valid journal entry
  71                  * if it has any journal entries at all.
  72                  */
  73
  74                 j = data;
  75                 while (len) {
  76                         struct list_head *where;
  77                         size_t blocks, bytes = set_bytes(j);
  78
  79                         if (j->magic != jset_magic(&ca->sb)) {
  80                                 pr_debug("%u: bad magic", bucket_index);
  81                                 return ret;
  82                         }
  83
  84                         if (bytes > left << 9 ||
  85                             bytes > PAGE_SIZE << JSET_BITS) {
  86                                 pr_info("%u: too big, %zu bytes, offset %u",
  87                                         bucket_index, bytes, offset);
  88                                 return ret;
  89                         }
  90
  91                         if (bytes > len << 9)
  92                                 goto reread;
  93
  94                         if (j->csum != csum_set(j)) {
  95                                 pr_info("%u: bad csum, %zu bytes, offset %u",
  96                                         bucket_index, bytes, offset);
  97                                 return ret;
  98                         }
  99
 100                         blocks = set_blocks(j, block_bytes(ca->set));
 101
 102                         while (!list_empty(list)) {
 103                                 i = list_first_entry(list,
 104                                         struct journal_replay, list);
 105                                 if (i->j.seq >= j->last_seq)
 106                                         break;
 107                                 list_del(&i->list);
 108                                 kfree(i);
 109                         }
 110
 111                         list_for_each_entry_reverse(i, list, list) {
 112                                 if (j->seq == i->j.seq)
 113                                         goto next_set;
 114
 115                                 if (j->seq < i->j.last_seq)
 116                                         goto next_set;
 117
 118                                 if (j->seq > i->j.seq) {
 119                                         where = &i->list;
 120                                         goto add;
 121                                 }
 122                         }
 123
 124                         where = list;
 125 add:
 126                         i = kmalloc(offsetof(struct journal_replay, j) +
 127                                     bytes, GFP_KERNEL);
 128                         if (!i)
 129                                 return -ENOMEM;
 130                         memcpy(&i->j, j, bytes);
 131                         list_add(&i->list, where);
 132                         ret = 1;
 133
 134                         ja->seq[bucket_index] = j->seq;
 135 next_set:
 136                         offset  += blocks * ca->sb.block_size;
 137                         len     -= blocks * ca->sb.block_size;
 138                         j = ((void *) j) + blocks * block_bytes(ca);
 139                 }
 140         }
 141
 142         return ret;
 143 }
 144
 145 int bch_journal_read(struct cache_set *c, struct list_head *list)
 146 {
 147 #define read_bucket(b)                                                  \
 148         ({                                                              \
 149                 int ret = journal_read_bucket(ca, list, b);             \
 150                 __set_bit(b, bitmap);                                   \
 151                 if (ret < 0)                                            \
 152                         return ret;                                     \
 153                 ret;                                                    \
 154         })
 155
 156         struct cache *ca;
 157         unsigned iter;
 158
 159         for_each_cache(ca, c, iter) {
 160                 struct journal_device *ja = &ca->journal;
 161                 DECLARE_BITMAP(bitmap, SB_JOURNAL_BUCKETS);
 162                 unsigned i, l, r, m;
 163                 uint64_t seq;
 164
 165                 bitmap_zero(bitmap, SB_JOURNAL_BUCKETS);
 166                 pr_debug("%u journal buckets", ca->sb.njournal_buckets);
 167
 168                 /*
 169                  * Read journal buckets ordered by golden ratio hash to quickly
 170                  * find a sequence of buckets with valid journal entries
 171                  */
 172                 for (i = 0; i < ca->sb.njournal_buckets; i++) {
 173                         /*
 174                          * We must try the index l with ZERO first for
 175                          * correctness due to the scenario that the journal
 176                          * bucket is circular buffer which might have wrapped
 177                          */
 178                         l = (i * 2654435769U) % ca->sb.njournal_buckets;
 179
 180                         if (test_bit(l, bitmap))
 181                                 break;
 182
 183                         if (read_bucket(l))
 184                                 goto bsearch;
 185                 }
 186
 187                 /*
 188                  * If that fails, check all the buckets we haven't checked
 189                  * already
 190                  */
 191                 pr_debug("falling back to linear search");
 192
 193                 for (l = find_first_zero_bit(bitmap, ca->sb.njournal_buckets);
 194                      l < ca->sb.njournal_buckets;
 195                      l = find_next_zero_bit(bitmap, ca->sb.njournal_buckets, l + 1))
 196                         if (read_bucket(l))
 197                                 goto bsearch;
 198
 199                 /* no journal entries on this device? */
 200                 if (l == ca->sb.njournal_buckets)
 201                         continue;
 202 bsearch:
 203                 BUG_ON(list_empty(list));
 204
 205                 /* Binary search */
 206                 m = l;
 207                 r = find_next_bit(bitmap, ca->sb.njournal_buckets, l + 1);
 208                 pr_debug("starting binary search, l %u r %u", l, r);
 209
 210                 while (l + 1 < r) {
 211                         seq = list_entry(list->prev, struct journal_replay,
 212                                          list)->j.seq;
 213
 214                         m = (l + r) >> 1;
 215                         read_bucket(m);
 216
 217                         if (seq != list_entry(list->prev, struct journal_replay,
 218                                               list)->j.seq)
 219                                 l = m;
 220                         else
 221                                 r = m;
 222                 }
 223
 224                 /*
 225                  * Read buckets in reverse order until we stop finding more
 226                  * journal entries
 227                  */
 228                 pr_debug("finishing up: m %u njournal_buckets %u",
 229                          m, ca->sb.njournal_buckets);
 230                 l = m;
 231
 232                 while (1) {
 233                         if (!l--)
 234                                 l = ca->sb.njournal_buckets - 1;
 235
 236                         if (l == m)
 237                                 break;
 238
 239                         if (test_bit(l, bitmap))
 240                                 continue;
 241
 242                         if (!read_bucket(l))
 243                                 break;
 244                 }
 245
 246                 seq = 0;
 247
 248                 for (i = 0; i < ca->sb.njournal_buckets; i++)
 249                         if (ja->seq[i] > seq) {
 250                                 seq = ja->seq[i];
 251                                 /*
 252                                  * When journal_reclaim() goes to allocate for
 253                                  * the first time, it'll use the bucket after
 254                                  * ja->cur_idx
 255                                  */
 256                                 ja->cur_idx = i;
 257                                 ja->last_idx = ja->discard_idx = (i + 1) %
 258                                         ca->sb.njournal_buckets;
 259
 260                         }
 261         }
 262
 263         if (!list_empty(list))
 264                 c->journal.seq = list_entry(list->prev,
 265                                             struct journal_replay,
 266                                             list)->j.seq;
 267
 268         return 0;
 269 #undef read_bucket
 270 }
 271
 272 void bch_journal_mark(struct cache_set *c, struct list_head *list)
 273 {
 274         atomic_t p = { 0 };
 275         struct bkey *k;
 276         struct journal_replay *i;
 277         struct journal *j = &c->journal;
 278         uint64_t last = j->seq;
 279
 280         /*
 281          * journal.pin should never fill up - we never write a journal
 282          * entry when it would fill up. But if for some reason it does, we
 283          * iterate over the list in reverse order so that we can just skip that
 284          * refcount instead of bugging.
 285          */
 286
 287         list_for_each_entry_reverse(i, list, list) {
 288                 BUG_ON(last < i->j.seq);
 289                 i->pin = NULL;
 290
 291                 while (last-- != i->j.seq)
 292                         if (fifo_free(&j->pin) > 1) {
 293                                 fifo_push_front(&j->pin, p);
 294                                 atomic_set(&fifo_front(&j->pin), 0);
 295                         }
 296
 297                 if (fifo_free(&j->pin) > 1) {
 298                         fifo_push_front(&j->pin, p);
 299                         i->pin = &fifo_front(&j->pin);
 300                         atomic_set(i->pin, 1);
 301                 }
 302
 303                 for (k = i->j.start;
 304                      k < bset_bkey_last(&i->j);
 305                      k = bkey_next(k))
 306                         if (!__bch_extent_invalid(c, k)) {
 307                                 unsigned j;
 308
 309                                 for (j = 0; j < KEY_PTRS(k); j++)
 310                                         if (ptr_available(c, k, j))
 311                                                 atomic_inc(&PTR_BUCKET(c, k, j)->pin);
 312
 313                                 bch_initial_mark_key(c, 0, k);
 314                         }
 315         }
 316 }
 317
 318 int bch_journal_replay(struct cache_set *s, struct list_head *list)
 319 {
 320         int ret = 0, keys = 0, entries = 0;
 321         struct bkey *k;
 322         struct journal_replay *i =
 323                 list_entry(list->prev, struct journal_replay, list);
 324
 325         uint64_t start = i->j.last_seq, end = i->j.seq, n = start;
 326         struct keylist keylist;
 327
 328         list_for_each_entry(i, list, list) {
 329                 BUG_ON(i->pin && atomic_read(i->pin) != 1);
 330
 331                 cache_set_err_on(n != i->j.seq, s,
 332 "bcache: journal entries %llu-%llu missing! (replaying %llu-%llu)",
 333                                  n, i->j.seq - 1, start, end);
 334
 335                 for (k = i->j.start;
 336                      k < bset_bkey_last(&i->j);
 337                      k = bkey_next(k)) {
 338                         trace_bcache_journal_replay_key(k);
 339
 340                         bch_keylist_init_single(&keylist, k);
 341
 342                         ret = bch_btree_insert(s, &keylist, i->pin, NULL);
 343                         if (ret)
 344                                 goto err;
 345
 346                         BUG_ON(!bch_keylist_empty(&keylist));
 347                         keys++;
 348
 349                         cond_resched();
 350                 }
 351
 352                 if (i->pin)
 353                         atomic_dec(i->pin);
 354                 n = i->j.seq + 1;
 355                 entries++;
 356         }
 357
 358         pr_info("journal replay done, %i keys in %i entries, seq %llu",
 359                 keys, entries, end);
 360 err:
 361         while (!list_empty(list)) {
 362                 i = list_first_entry(list, struct journal_replay, list);
 363                 list_del(&i->list);
 364                 kfree(i);
 365         }
 366
 367         return ret;
 368 }
 369
 370 /* Journalling */
 371 #define journal_max_cmp(l, r) \
 372         (fifo_idx(&c->journal.pin, btree_current_write(l)->journal) < \
 373          fifo_idx(&(c)->journal.pin, btree_current_write(r)->journal))
 374 #define journal_min_cmp(l, r) \
 375         (fifo_idx(&c->journal.pin, btree_current_write(l)->journal) > \
 376          fifo_idx(&(c)->journal.pin, btree_current_write(r)->journal))
 377
 378 static void btree_flush_write(struct cache_set *c)
 379 {
 380         /*
 381          * Try to find the btree node with that references the oldest journal
 382          * entry, best is our current candidate and is locked if non NULL:
 383          */
 384         struct btree *b;
 385         int i;
 386
 387         atomic_long_inc(&c->flush_write);
 388
 389 retry:
 390         spin_lock(&c->journal.lock);
 391         if (heap_empty(&c->flush_btree)) {
 392                 for_each_cached_btree(b, c, i)
 393                         if (btree_current_write(b)->journal) {
 394                                 if (!heap_full(&c->flush_btree))
 395                                         heap_add(&c->flush_btree, b,
 396                                                  journal_max_cmp);
 397                                 else if (journal_max_cmp(b,
 398                                          heap_peek(&c->flush_btree))) {
 399                                         c->flush_btree.data[0] = b;
 400                                         heap_sift(&c->flush_btree, 0,
 401                                                   journal_max_cmp);
 402                                 }
 403                         }
 404
 405                 for (i = c->flush_btree.used / 2 - 1; i >= 0; --i)
 406                         heap_sift(&c->flush_btree, i, journal_min_cmp);
 407         }
 408
 409         b = NULL;
 410         heap_pop(&c->flush_btree, b, journal_min_cmp);
 411         spin_unlock(&c->journal.lock);
 412
 413         if (b) {
 414                 mutex_lock(&b->write_lock);
 415                 if (!btree_current_write(b)->journal) {
 416                         mutex_unlock(&b->write_lock);
 417                         /* We raced */
 418                         atomic_long_inc(&c->retry_flush_write);
 419                         goto retry;
 420                 }
 421
 422                 __bch_btree_node_write(b, NULL);
 423                 mutex_unlock(&b->write_lock);
 424         }
 425 }
 426
 427 #define last_seq(j)     ((j)->seq - fifo_used(&(j)->pin) + 1)
 428
 429 static void journal_discard_endio(struct bio *bio)
 430 {
 431         struct journal_device *ja =
 432                 container_of(bio, struct journal_device, discard_bio);
 433         struct cache *ca = container_of(ja, struct cache, journal);
 434
 435         atomic_set(&ja->discard_in_flight, DISCARD_DONE);
 436
 437         closure_wake_up(&ca->set->journal.wait);
 438         closure_put(&ca->set->cl);
 439 }
 440
 441 static void journal_discard_work(struct work_struct *work)
 442 {
 443         struct journal_device *ja =
 444                 container_of(work, struct journal_device, discard_work);
 445
 446         submit_bio(&ja->discard_bio);
 447 }
 448
 449 static void do_journal_discard(struct cache *ca)
 450 {
 451         struct journal_device *ja = &ca->journal;
 452         struct bio *bio = &ja->discard_bio;
 453
 454         if (!ca->discard) {
 455                 ja->discard_idx = ja->last_idx;
 456                 return;
 457         }
 458
 459         switch (atomic_read(&ja->discard_in_flight)) {
 460         case DISCARD_IN_FLIGHT:
 461                 return;
 462
 463         case DISCARD_DONE:
 464                 ja->discard_idx = (ja->discard_idx + 1) %
 465                         ca->sb.njournal_buckets;
 466
 467                 atomic_set(&ja->discard_in_flight, DISCARD_READY);
 468                 /* fallthrough */
 469
 470         case DISCARD_READY:
 471                 if (ja->discard_idx == ja->last_idx)
 472                         return;
 473
 474                 atomic_set(&ja->discard_in_flight, DISCARD_IN_FLIGHT);
 475
 476                 bio_init(bio, bio->bi_inline_vecs, 1);
 477                 bio_set_op_attrs(bio, REQ_OP_DISCARD, 0);
 478                 bio->bi_iter.bi_sector  = bucket_to_sector(ca->set,
 479                                                 ca->sb.d[ja->discard_idx]);
 480                 bio_set_dev(bio, ca->bdev);
 481                 bio->bi_iter.bi_size    = bucket_bytes(ca);
 482                 bio->bi_end_io          = journal_discard_endio;
 483
 484                 closure_get(&ca->set->cl);
 485                 INIT_WORK(&ja->discard_work, journal_discard_work);
 486                 schedule_work(&ja->discard_work);
 487         }
 488 }
 489
 490 static void journal_reclaim(struct cache_set *c)
 491 {
 492         struct bkey *k = &c->journal.key;
 493         struct cache *ca;
 494         uint64_t last_seq;
 495         unsigned iter, n = 0;
 496         atomic_t p;
 497
 498         atomic_long_inc(&c->reclaim);
 499
 500         while (!atomic_read(&fifo_front(&c->journal.pin)))
 501                 fifo_pop(&c->journal.pin, p);
 502
 503         last_seq = last_seq(&c->journal);
 504
 505         /* Update last_idx */
 506
 507         for_each_cache(ca, c, iter) {
 508                 struct journal_device *ja = &ca->journal;
 509
 510                 while (ja->last_idx != ja->cur_idx &&
 511                        ja->seq[ja->last_idx] < last_seq)
 512                         ja->last_idx = (ja->last_idx + 1) %
 513                                 ca->sb.njournal_buckets;
 514         }
 515
 516         for_each_cache(ca, c, iter)
 517                 do_journal_discard(ca);
 518
 519         if (c->journal.blocks_free)
 520                 goto out;
 521
 522         /*
 523          * Allocate:
 524          * XXX: Sort by free journal space
 525          */
 526
 527         for_each_cache(ca, c, iter) {
 528                 struct journal_device *ja = &ca->journal;
 529                 unsigned next = (ja->cur_idx + 1) % ca->sb.njournal_buckets;
 530
 531                 /* No space available on this device */
 532                 if (next == ja->discard_idx)
 533                         continue;
 534
 535                 ja->cur_idx = next;
 536                 k->ptr[n++] = MAKE_PTR(0,
 537                                   bucket_to_sector(c, ca->sb.d[ja->cur_idx]),
 538                                   ca->sb.nr_this_dev);
 539         }
 540
 541         bkey_init(k);
 542         SET_KEY_PTRS(k, n);
 543
 544         if (n)
 545                 c->journal.blocks_free = c->sb.bucket_size >> c->block_bits;
 546 out:
 547         if (!journal_full(&c->journal))
 548                 __closure_wake_up(&c->journal.wait);
 549 }
 550
 551 void bch_journal_next(struct journal *j)
 552 {
 553         atomic_t p = { 1 };
 554
 555         j->cur = (j->cur == j->w)
 556                 ? &j->w[1]
 557                 : &j->w[0];
 558
 559         /*
 560          * The fifo_push() needs to happen at the same time as j->seq is
 561          * incremented for last_seq() to be calculated correctly
 562          */
 563         BUG_ON(!fifo_push(&j->pin, p));
 564         atomic_set(&fifo_back(&j->pin), 1);
 565
 566         j->cur->data->seq       = ++j->seq;
 567         j->cur->dirty           = false;
 568         j->cur->need_write      = false;
 569         j->cur->data->keys      = 0;
 570
 571         if (fifo_full(&j->pin))
 572                 pr_debug("journal_pin full (%zu)", fifo_used(&j->pin));
 573 }
 574
 575 static void journal_write_endio(struct bio *bio)
 576 {
 577         struct journal_write *w = bio->bi_private;
 578
 579         cache_set_err_on(bio->bi_status, w->c, "journal io error");
 580         closure_put(&w->c->journal.io);
 581 }
 582
 583 static void journal_write(struct closure *);
 584
 585 static void journal_write_done(struct closure *cl)
 586 {
 587         struct journal *j = container_of(cl, struct journal, io);
 588         struct journal_write *w = (j->cur == j->w)
 589                 ? &j->w[1]
 590                 : &j->w[0];
 591
 592         __closure_wake_up(&w->wait);
 593         continue_at_nobarrier(cl, journal_write, system_wq);
 594 }
 595
 596 static void journal_write_unlock(struct closure *cl)
 597 {
 598         struct cache_set *c = container_of(cl, struct cache_set, journal.io);
 599
 600         c->journal.io_in_flight = 0;
 601         spin_unlock(&c->journal.lock);
 602 }
 603
 604 static void journal_write_unlocked(struct closure *cl)
 605         __releases(c->journal.lock)
 606 {
 607         struct cache_set *c = container_of(cl, struct cache_set, journal.io);
 608         struct cache *ca;
 609         struct journal_write *w = c->journal.cur;
 610         struct bkey *k = &c->journal.key;
 611         unsigned i, sectors = set_blocks(w->data, block_bytes(c)) *
 612                 c->sb.block_size;
 613
 614         struct bio *bio;
 615         struct bio_list list;
 616         bio_list_init(&list);
 617
 618         if (!w->need_write) {
 619                 closure_return_with_destructor(cl, journal_write_unlock);
 620                 return;
 621         } else if (journal_full(&c->journal)) {
 622                 journal_reclaim(c);
 623                 spin_unlock(&c->journal.lock);
 624
 625                 btree_flush_write(c);
 626                 continue_at(cl, journal_write, system_wq);
 627                 return;
 628         }
 629
 630         c->journal.blocks_free -= set_blocks(w->data, block_bytes(c));
 631
 632         w->data->btree_level = c->root->level;
 633
 634         bkey_copy(&w->data->btree_root, &c->root->key);
 635         bkey_copy(&w->data->uuid_bucket, &c->uuid_bucket);
 636
 637         for_each_cache(ca, c, i)
 638                 w->data->prio_bucket[ca->sb.nr_this_dev] = ca->prio_buckets[0];
 639
 640         w->data->magic          = jset_magic(&c->sb);
 641         w->data->version        = BCACHE_JSET_VERSION;
 642         w->data->last_seq       = last_seq(&c->journal);
 643         w->data->csum           = csum_set(w->data);
 644
 645         for (i = 0; i < KEY_PTRS(k); i++) {
 646                 ca = PTR_CACHE(c, k, i);
 647                 bio = &ca->journal.bio;
 648
 649                 atomic_long_add(sectors, &ca->meta_sectors_written);
 650
 651                 bio_reset(bio);
 652                 bio->bi_iter.bi_sector  = PTR_OFFSET(k, i);
 653                 bio_set_dev(bio, ca->bdev);
 654                 bio->bi_iter.bi_size = sectors << 9;
 655
 656                 bio->bi_end_io  = journal_write_endio;
 657                 bio->bi_private = w;
 658                 bio_set_op_attrs(bio, REQ_OP_WRITE,
 659                                  REQ_SYNC|REQ_META|REQ_PREFLUSH|REQ_FUA);
 660                 bch_bio_map(bio, w->data);
 661
 662                 trace_bcache_journal_write(bio);
 663                 bio_list_add(&list, bio);
 664
 665                 SET_PTR_OFFSET(k, i, PTR_OFFSET(k, i) + sectors);
 666
 667                 ca->journal.seq[ca->journal.cur_idx] = w->data->seq;
 668         }
 669
 670         atomic_dec_bug(&fifo_back(&c->journal.pin));
 671         bch_journal_next(&c->journal);
 672         journal_reclaim(c);
 673
 674         spin_unlock(&c->journal.lock);
 675
 676         while ((bio = bio_list_pop(&list)))
 677                 closure_bio_submit(bio, cl);
 678
 679         continue_at(cl, journal_write_done, NULL);
 680 }
 681
 682 static void journal_write(struct closure *cl)
 683 {
 684         struct cache_set *c = container_of(cl, struct cache_set, journal.io);
 685
 686         spin_lock(&c->journal.lock);
 687         journal_write_unlocked(cl);
 688 }
 689
 690 static void journal_try_write(struct cache_set *c)
 691         __releases(c->journal.lock)
 692 {
 693         struct closure *cl = &c->journal.io;
 694         struct journal_write *w = c->journal.cur;
 695
 696         w->need_write = true;
 697
 698         if (!c->journal.io_in_flight) {
 699                 c->journal.io_in_flight = 1;
 700                 closure_call(cl, journal_write_unlocked, NULL, &c->cl);
 701         } else {
 702                 spin_unlock(&c->journal.lock);
 703         }
 704 }
 705
 706 static struct journal_write *journal_wait_for_write(struct cache_set *c,
 707                                                     unsigned nkeys)
 708 {
 709         size_t sectors;
 710         struct closure cl;
 711         bool wait = false;
 712
 713         closure_init_stack(&cl);
 714
 715         spin_lock(&c->journal.lock);
 716
 717         while (1) {
 718                 struct journal_write *w = c->journal.cur;
 719
 720                 sectors = __set_blocks(w->data, w->data->keys + nkeys,
 721                                        block_bytes(c)) * c->sb.block_size;
 722
 723                 if (sectors <= min_t(size_t,
 724                                      c->journal.blocks_free * c->sb.block_size,
 725                                      PAGE_SECTORS << JSET_BITS))
 726                         return w;
 727
 728                 if (wait)
 729                         closure_wait(&c->journal.wait, &cl);
 730
 731                 if (!journal_full(&c->journal)) {
 732                         if (wait)
 733                                 trace_bcache_journal_entry_full(c);
 734
 735                         /*
 736                          * XXX: If we were inserting so many keys that they
 737                          * won't fit in an _empty_ journal write, we'll
 738                          * deadlock. For now, handle this in
 739                          * bch_keylist_realloc() - but something to think about.
 740                          */
 741                         BUG_ON(!w->data->keys);
 742
 743                         journal_try_write(c); /* unlocks */
 744                 } else {
 745                         if (wait)
 746                                 trace_bcache_journal_full(c);
 747
 748                         journal_reclaim(c);
 749                         spin_unlock(&c->journal.lock);
 750
 751                         btree_flush_write(c);
 752                 }
 753
 754                 closure_sync(&cl);
 755                 spin_lock(&c->journal.lock);
 756                 wait = true;
 757         }
 758 }
 759
 760 static void journal_write_work(struct work_struct *work)
 761 {
 762         struct cache_set *c = container_of(to_delayed_work(work),
 763                                            struct cache_set,
 764                                            journal.work);
 765         spin_lock(&c->journal.lock);
 766         if (c->journal.cur->dirty)
 767                 journal_try_write(c);
 768         else
 769                 spin_unlock(&c->journal.lock);
 770 }
 771
 772 /*
 773  * Entry point to the journalling code - bio_insert() and btree_invalidate()
 774  * pass bch_journal() a list of keys to be journalled, and then
 775  * bch_journal() hands those same keys off to btree_insert_async()
 776  */
 777
 778 atomic_t *bch_journal(struct cache_set *c,
 779                       struct keylist *keys,
 780                       struct closure *parent)
 781 {
 782         struct journal_write *w;
 783         atomic_t *ret;
 784
 785         if (!CACHE_SYNC(&c->sb))
 786                 return NULL;
 787
 788         w = journal_wait_for_write(c, bch_keylist_nkeys(keys));
 789
 790         memcpy(bset_bkey_last(w->data), keys->keys, bch_keylist_bytes(keys));
 791         w->data->keys += bch_keylist_nkeys(keys);
 792
 793         ret = &fifo_back(&c->journal.pin);
 794         atomic_inc(ret);
 795
 796         if (parent) {
 797                 closure_wait(&w->wait, parent);
 798                 journal_try_write(c);
 799         } else if (!w->dirty) {
 800                 w->dirty = true;
 801                 schedule_delayed_work(&c->journal.work,
 802                                       msecs_to_jiffies(c->journal_delay_ms));
 803                 spin_unlock(&c->journal.lock);
 804         } else {
 805                 spin_unlock(&c->journal.lock);
 806         }
 807
 808
 809         return ret;
 810 }
 811
 812 void bch_journal_meta(struct cache_set *c, struct closure *cl)
 813 {
 814         struct keylist keys;
 815         atomic_t *ref;
 816
 817         bch_keylist_init(&keys);
 818
 819         ref = bch_journal(c, &keys, cl);
 820         if (ref)
 821                 atomic_dec_bug(ref);
 822 }
 823
 824 void bch_journal_free(struct cache_set *c)
 825 {
 826         free_pages((unsigned long) c->journal.w[1].data, JSET_BITS);
 827         free_pages((unsigned long) c->journal.w[0].data, JSET_BITS);
 828         free_fifo(&c->journal.pin);
 829 }
 830
 831 int bch_journal_alloc(struct cache_set *c)
 832 {
 833         struct journal *j = &c->journal;
 834
 835         spin_lock_init(&j->lock);
 836         INIT_DELAYED_WORK(&j->work, journal_write_work);
 837
 838         c->journal_delay_ms = 100;
 839
 840         j->w[0].c = c;
 841         j->w[1].c = c;
 842
 843         if (!(init_heap(&c->flush_btree, 128, GFP_KERNEL)) ||
 844             !(init_fifo(&j->pin, JOURNAL_PIN, GFP_KERNEL)) ||
 845             !(j->w[0].data = (void *) __get_free_pages(GFP_KERNEL, JSET_BITS)) ||
 846             !(j->w[1].data = (void *) __get_free_pages(GFP_KERNEL, JSET_BITS)))
 847                 return -ENOMEM;
 848
 849         return 0;
 850 }