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 candidate 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 following 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 = c->cache;
 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                 queue_delayed_work(bch_flush_wq, &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 }