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", 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", 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",
  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",
  97                                         bucket_index, bytes, offset);
  98                                 return ret;
  99                         }
 100
 101                         blocks = set_blocks(j, block_bytes(ca->set));
 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;
 183         unsigned int iter;
 184         int ret = 0;
 185
 186         for_each_cache(ca, c, iter) {
 187                 struct journal_device *ja = &ca->journal;
 188                 DECLARE_BITMAP(bitmap, SB_JOURNAL_BUCKETS);
 189                 unsigned int i, l, r, m;
 190                 uint64_t seq;
 191
 192                 bitmap_zero(bitmap, SB_JOURNAL_BUCKETS);
 193                 pr_debug("%u journal buckets", ca->sb.njournal_buckets);
 194
 195                 /*
 196                  * Read journal buckets ordered by golden ratio hash to quickly
 197                  * find a sequence of buckets with valid journal entries
 198                  */
 199                 for (i = 0; i < ca->sb.njournal_buckets; i++) {
 200                         /*
 201                          * We must try the index l with ZERO first for
 202                          * correctness due to the scenario that the journal
 203                          * bucket is circular buffer which might have wrapped
 204                          */
 205                         l = (i * 2654435769U) % ca->sb.njournal_buckets;
 206
 207                         if (test_bit(l, bitmap))
 208                                 break;
 209
 210                         if (read_bucket(l))
 211                                 goto bsearch;
 212                 }
 213
 214                 /*
 215                  * If that fails, check all the buckets we haven't checked
 216                  * already
 217                  */
 218                 pr_debug("falling back to linear search");
 219
 220                 for (l = find_first_zero_bit(bitmap, ca->sb.njournal_buckets);
 221                      l < ca->sb.njournal_buckets;
 222                      l = find_next_zero_bit(bitmap, ca->sb.njournal_buckets,
 223                                             l + 1))
 224                         if (read_bucket(l))
 225                                 goto bsearch;
 226
 227                 /* no journal entries on this device? */
 228                 if (l == ca->sb.njournal_buckets)
 229                         continue;
 230 bsearch:
 231                 BUG_ON(list_empty(list));
 232
 233                 /* Binary search */
 234                 m = l;
 235                 r = find_next_bit(bitmap, ca->sb.njournal_buckets, l + 1);
 236                 pr_debug("starting binary search, l %u r %u", l, r);
 237
 238                 while (l + 1 < r) {
 239                         seq = list_entry(list->prev, struct journal_replay,
 240                                          list)->j.seq;
 241
 242                         m = (l + r) >> 1;
 243                         read_bucket(m);
 244
 245                         if (seq != list_entry(list->prev, struct journal_replay,
 246                                               list)->j.seq)
 247                                 l = m;
 248                         else
 249                                 r = m;
 250                 }
 251
 252                 /*
 253                  * Read buckets in reverse order until we stop finding more
 254                  * journal entries
 255                  */
 256                 pr_debug("finishing up: m %u njournal_buckets %u",
 257                          m, ca->sb.njournal_buckets);
 258                 l = m;
 259
 260                 while (1) {
 261                         if (!l--)
 262                                 l = ca->sb.njournal_buckets - 1;
 263
 264                         if (l == m)
 265                                 break;
 266
 267                         if (test_bit(l, bitmap))
 268                                 continue;
 269
 270                         if (!read_bucket(l))
 271                                 break;
 272                 }
 273
 274                 seq = 0;
 275
 276                 for (i = 0; i < ca->sb.njournal_buckets; i++)
 277                         if (ja->seq[i] > seq) {
 278                                 seq = ja->seq[i];
 279                                 /*
 280                                  * When journal_reclaim() goes to allocate for
 281                                  * the first time, it'll use the bucket after
 282                                  * ja->cur_idx
 283                                  */
 284                                 ja->cur_idx = i;
 285                                 ja->last_idx = ja->discard_idx = (i + 1) %
 286                                         ca->sb.njournal_buckets;
 287
 288                         }
 289         }
 290
 291         if (!list_empty(list))
 292                 c->journal.seq = list_entry(list->prev,
 293                                             struct journal_replay,
 294                                             list)->j.seq;
 295
 296         return 0;
 297 #undef read_bucket
 298 }
 299
 300 void bch_journal_mark(struct cache_set *c, struct list_head *list)
 301 {
 302         atomic_t p = { 0 };
 303         struct bkey *k;
 304         struct journal_replay *i;
 305         struct journal *j = &c->journal;
 306         uint64_t last = j->seq;
 307
 308         /*
 309          * journal.pin should never fill up - we never write a journal
 310          * entry when it would fill up. But if for some reason it does, we
 311          * iterate over the list in reverse order so that we can just skip that
 312          * refcount instead of bugging.
 313          */
 314
 315         list_for_each_entry_reverse(i, list, list) {
 316                 BUG_ON(last < i->j.seq);
 317                 i->pin = NULL;
 318
 319                 while (last-- != i->j.seq)
 320                         if (fifo_free(&j->pin) > 1) {
 321                                 fifo_push_front(&j->pin, p);
 322                                 atomic_set(&fifo_front(&j->pin), 0);
 323                         }
 324
 325                 if (fifo_free(&j->pin) > 1) {
 326                         fifo_push_front(&j->pin, p);
 327                         i->pin = &fifo_front(&j->pin);
 328                         atomic_set(i->pin, 1);
 329                 }
 330
 331                 for (k = i->j.start;
 332                      k < bset_bkey_last(&i->j);
 333                      k = bkey_next(k))
 334                         if (!__bch_extent_invalid(c, k)) {
 335                                 unsigned int j;
 336
 337                                 for (j = 0; j < KEY_PTRS(k); j++)
 338                                         if (ptr_available(c, k, j))
 339                                                 atomic_inc(&PTR_BUCKET(c, k, j)->pin);
 340
 341                                 bch_initial_mark_key(c, 0, k);
 342                         }
 343         }
 344 }
 345
 346 static bool is_discard_enabled(struct cache_set *s)
 347 {
 348         struct cache *ca;
 349         unsigned int i;
 350
 351         for_each_cache(ca, s, i)
 352                 if (ca->discard)
 353                         return true;
 354
 355         return false;
 356 }
 357
 358 int bch_journal_replay(struct cache_set *s, struct list_head *list)
 359 {
 360         int ret = 0, keys = 0, entries = 0;
 361         struct bkey *k;
 362         struct journal_replay *i =
 363                 list_entry(list->prev, struct journal_replay, list);
 364
 365         uint64_t start = i->j.last_seq, end = i->j.seq, n = start;
 366         struct keylist keylist;
 367
 368         list_for_each_entry(i, list, list) {
 369                 BUG_ON(i->pin && atomic_read(i->pin) != 1);
 370
 371                 if (n != i->j.seq) {
 372                         if (n == start && is_discard_enabled(s))
 373                                 pr_info("bcache: journal entries %llu-%llu may be discarded! (replaying %llu-%llu)",
 374                                         n, i->j.seq - 1, start, end);
 375                         else {
 376                                 pr_err("bcache: journal entries %llu-%llu missing! (replaying %llu-%llu)",
 377                                         n, i->j.seq - 1, start, end);
 378                                 ret = -EIO;
 379                                 goto err;
 380                         }
 381                 }
 382
 383                 for (k = i->j.start;
 384                      k < bset_bkey_last(&i->j);
 385                      k = bkey_next(k)) {
 386                         trace_bcache_journal_replay_key(k);
 387
 388                         bch_keylist_init_single(&keylist, k);
 389
 390                         ret = bch_btree_insert(s, &keylist, i->pin, NULL);
 391                         if (ret)
 392                                 goto err;
 393
 394                         BUG_ON(!bch_keylist_empty(&keylist));
 395                         keys++;
 396
 397                         cond_resched();
 398                 }
 399
 400                 if (i->pin)
 401                         atomic_dec(i->pin);
 402                 n = i->j.seq + 1;
 403                 entries++;
 404         }
 405
 406         pr_info("journal replay done, %i keys in %i entries, seq %llu",
 407                 keys, entries, end);
 408 err:
 409         while (!list_empty(list)) {
 410                 i = list_first_entry(list, struct journal_replay, list);
 411                 list_del(&i->list);
 412                 kfree(i);
 413         }
 414
 415         return ret;
 416 }
 417
 418 /* Journalling */
 419
 420 #define nr_to_fifo_front(p, front_p, mask)      (((p) - (front_p)) & (mask))
 421
 422 static void btree_flush_write(struct cache_set *c)
 423 {
 424         struct btree *b, *t, *btree_nodes[BTREE_FLUSH_NR];
 425         unsigned int i, nr, ref_nr;
 426         atomic_t *fifo_front_p, *now_fifo_front_p;
 427         size_t mask;
 428
 429         if (c->journal.btree_flushing)
 430                 return;
 431
 432         spin_lock(&c->journal.flush_write_lock);
 433         if (c->journal.btree_flushing) {
 434                 spin_unlock(&c->journal.flush_write_lock);
 435                 return;
 436         }
 437         c->journal.btree_flushing = true;
 438         spin_unlock(&c->journal.flush_write_lock);
 439
 440         /* get the oldest journal entry and check its refcount */
 441         spin_lock(&c->journal.lock);
 442         fifo_front_p = &fifo_front(&c->journal.pin);
 443         ref_nr = atomic_read(fifo_front_p);
 444         if (ref_nr <= 0) {
 445                 /*
 446                  * do nothing if no btree node references
 447                  * the oldest journal entry
 448                  */
 449                 spin_unlock(&c->journal.lock);
 450                 goto out;
 451         }
 452         spin_unlock(&c->journal.lock);
 453
 454         mask = c->journal.pin.mask;
 455         nr = 0;
 456         atomic_long_inc(&c->flush_write);
 457         memset(btree_nodes, 0, sizeof(btree_nodes));
 458
 459         mutex_lock(&c->bucket_lock);
 460         list_for_each_entry_safe_reverse(b, t, &c->btree_cache, list) {
 461                 /*
 462                  * It is safe to get now_fifo_front_p without holding
 463                  * c->journal.lock here, because we don't need to know
 464                  * the exactly accurate value, just check whether the
 465                  * front pointer of c->journal.pin is changed.
 466                  */
 467                 now_fifo_front_p = &fifo_front(&c->journal.pin);
 468                 /*
 469                  * If the oldest journal entry is reclaimed and front
 470                  * pointer of c->journal.pin changes, it is unnecessary
 471                  * to scan c->btree_cache anymore, just quit the loop and
 472                  * flush out what we have already.
 473                  */
 474                 if (now_fifo_front_p != fifo_front_p)
 475                         break;
 476                 /*
 477                  * quit this loop if all matching btree nodes are
 478                  * scanned and record in btree_nodes[] already.
 479                  */
 480                 ref_nr = atomic_read(fifo_front_p);
 481                 if (nr >= ref_nr)
 482                         break;
 483
 484                 if (btree_node_journal_flush(b))
 485                         pr_err("BUG: flush_write bit should not be set here!");
 486
 487                 mutex_lock(&b->write_lock);
 488
 489                 if (!btree_node_dirty(b)) {
 490                         mutex_unlock(&b->write_lock);
 491                         continue;
 492                 }
 493
 494                 if (!btree_current_write(b)->journal) {
 495                         mutex_unlock(&b->write_lock);
 496                         continue;
 497                 }
 498
 499                 /*
 500                  * Only select the btree node which exactly references
 501                  * the oldest journal entry.
 502                  *
 503                  * If the journal entry pointed by fifo_front_p is
 504                  * reclaimed in parallel, don't worry:
 505                  * - the list_for_each_xxx loop will quit when checking
 506                  *   next now_fifo_front_p.
 507                  * - If there are matched nodes recorded in btree_nodes[],
 508                  *   they are clean now (this is why and how the oldest
 509                  *   journal entry can be reclaimed). These selected nodes
 510                  *   will be ignored and skipped in the folowing for-loop.
 511                  */
 512                 if (nr_to_fifo_front(btree_current_write(b)->journal,
 513                                      fifo_front_p,
 514                                      mask) != 0) {
 515                         mutex_unlock(&b->write_lock);
 516                         continue;
 517                 }
 518
 519                 set_btree_node_journal_flush(b);
 520
 521                 mutex_unlock(&b->write_lock);
 522
 523                 btree_nodes[nr++] = b;
 524                 /*
 525                  * To avoid holding c->bucket_lock too long time,
 526                  * only scan for BTREE_FLUSH_NR matched btree nodes
 527                  * at most. If there are more btree nodes reference
 528                  * the oldest journal entry, try to flush them next
 529                  * time when btree_flush_write() is called.
 530                  */
 531                 if (nr == BTREE_FLUSH_NR)
 532                         break;
 533         }
 534         mutex_unlock(&c->bucket_lock);
 535
 536         for (i = 0; i < nr; i++) {
 537                 b = btree_nodes[i];
 538                 if (!b) {
 539                         pr_err("BUG: btree_nodes[%d] is NULL", i);
 540                         continue;
 541                 }
 542
 543                 /* safe to check without holding b->write_lock */
 544                 if (!btree_node_journal_flush(b)) {
 545                         pr_err("BUG: bnode %p: journal_flush bit cleaned", b);
 546                         continue;
 547                 }
 548
 549                 mutex_lock(&b->write_lock);
 550                 if (!btree_current_write(b)->journal) {
 551                         clear_bit(BTREE_NODE_journal_flush, &b->flags);
 552                         mutex_unlock(&b->write_lock);
 553                         pr_debug("bnode %p: written by others", b);
 554                         continue;
 555                 }
 556
 557                 if (!btree_node_dirty(b)) {
 558                         clear_bit(BTREE_NODE_journal_flush, &b->flags);
 559                         mutex_unlock(&b->write_lock);
 560                         pr_debug("bnode %p: dirty bit cleaned by others", b);
 561                         continue;
 562                 }
 563
 564                 __bch_btree_node_write(b, NULL);
 565                 clear_bit(BTREE_NODE_journal_flush, &b->flags);
 566                 mutex_unlock(&b->write_lock);
 567         }
 568
 569 out:
 570         spin_lock(&c->journal.flush_write_lock);
 571         c->journal.btree_flushing = false;
 572         spin_unlock(&c->journal.flush_write_lock);
 573 }
 574
 575 #define last_seq(j)     ((j)->seq - fifo_used(&(j)->pin) + 1)
 576
 577 static void journal_discard_endio(struct bio *bio)
 578 {
 579         struct journal_device *ja =
 580                 container_of(bio, struct journal_device, discard_bio);
 581         struct cache *ca = container_of(ja, struct cache, journal);
 582
 583         atomic_set(&ja->discard_in_flight, DISCARD_DONE);
 584
 585         closure_wake_up(&ca->set->journal.wait);
 586         closure_put(&ca->set->cl);
 587 }
 588
 589 static void journal_discard_work(struct work_struct *work)
 590 {
 591         struct journal_device *ja =
 592                 container_of(work, struct journal_device, discard_work);
 593
 594         submit_bio(&ja->discard_bio);
 595 }
 596
 597 static void do_journal_discard(struct cache *ca)
 598 {
 599         struct journal_device *ja = &ca->journal;
 600         struct bio *bio = &ja->discard_bio;
 601
 602         if (!ca->discard) {
 603                 ja->discard_idx = ja->last_idx;
 604                 return;
 605         }
 606
 607         switch (atomic_read(&ja->discard_in_flight)) {
 608         case DISCARD_IN_FLIGHT:
 609                 return;
 610
 611         case DISCARD_DONE:
 612                 ja->discard_idx = (ja->discard_idx + 1) %
 613                         ca->sb.njournal_buckets;
 614
 615                 atomic_set(&ja->discard_in_flight, DISCARD_READY);
 616                 /* fallthrough */
 617
 618         case DISCARD_READY:
 619                 if (ja->discard_idx == ja->last_idx)
 620                         return;
 621
 622                 atomic_set(&ja->discard_in_flight, DISCARD_IN_FLIGHT);
 623
 624                 bio_init(bio, bio->bi_inline_vecs, 1);
 625                 bio_set_op_attrs(bio, REQ_OP_DISCARD, 0);
 626                 bio->bi_iter.bi_sector  = bucket_to_sector(ca->set,
 627                                                 ca->sb.d[ja->discard_idx]);
 628                 bio_set_dev(bio, ca->bdev);
 629                 bio->bi_iter.bi_size    = bucket_bytes(ca);
 630                 bio->bi_end_io          = journal_discard_endio;
 631
 632                 closure_get(&ca->set->cl);
 633                 INIT_WORK(&ja->discard_work, journal_discard_work);
 634                 queue_work(bch_journal_wq, &ja->discard_work);
 635         }
 636 }
 637
 638 static void journal_reclaim(struct cache_set *c)
 639 {
 640         struct bkey *k = &c->journal.key;
 641         struct cache *ca;
 642         uint64_t last_seq;
 643         unsigned int iter, n = 0;
 644         atomic_t p __maybe_unused;
 645
 646         atomic_long_inc(&c->reclaim);
 647
 648         while (!atomic_read(&fifo_front(&c->journal.pin)))
 649                 fifo_pop(&c->journal.pin, p);
 650
 651         last_seq = last_seq(&c->journal);
 652
 653         /* Update last_idx */
 654
 655         for_each_cache(ca, c, iter) {
 656                 struct journal_device *ja = &ca->journal;
 657
 658                 while (ja->last_idx != ja->cur_idx &&
 659                        ja->seq[ja->last_idx] < last_seq)
 660                         ja->last_idx = (ja->last_idx + 1) %
 661                                 ca->sb.njournal_buckets;
 662         }
 663
 664         for_each_cache(ca, c, iter)
 665                 do_journal_discard(ca);
 666
 667         if (c->journal.blocks_free)
 668                 goto out;
 669
 670         /*
 671          * Allocate:
 672          * XXX: Sort by free journal space
 673          */
 674
 675         for_each_cache(ca, c, iter) {
 676                 struct journal_device *ja = &ca->journal;
 677                 unsigned int next = (ja->cur_idx + 1) % ca->sb.njournal_buckets;
 678
 679                 /* No space available on this device */
 680                 if (next == ja->discard_idx)
 681                         continue;
 682
 683                 ja->cur_idx = next;
 684                 k->ptr[n++] = MAKE_PTR(0,
 685                                   bucket_to_sector(c, ca->sb.d[ja->cur_idx]),
 686                                   ca->sb.nr_this_dev);
 687                 atomic_long_inc(&c->reclaimed_journal_buckets);
 688         }
 689
 690         if (n) {
 691                 bkey_init(k);
 692                 SET_KEY_PTRS(k, n);
 693                 c->journal.blocks_free = c->sb.bucket_size >> c->block_bits;
 694         }
 695 out:
 696         if (!journal_full(&c->journal))
 697                 __closure_wake_up(&c->journal.wait);
 698 }
 699
 700 void bch_journal_next(struct journal *j)
 701 {
 702         atomic_t p = { 1 };
 703
 704         j->cur = (j->cur == j->w)
 705                 ? &j->w[1]
 706                 : &j->w[0];
 707
 708         /*
 709          * The fifo_push() needs to happen at the same time as j->seq is
 710          * incremented for last_seq() to be calculated correctly
 711          */
 712         BUG_ON(!fifo_push(&j->pin, p));
 713         atomic_set(&fifo_back(&j->pin), 1);
 714
 715         j->cur->data->seq       = ++j->seq;
 716         j->cur->dirty           = false;
 717         j->cur->need_write      = false;
 718         j->cur->data->keys      = 0;
 719
 720         if (fifo_full(&j->pin))
 721                 pr_debug("journal_pin full (%zu)", fifo_used(&j->pin));
 722 }
 723
 724 static void journal_write_endio(struct bio *bio)
 725 {
 726         struct journal_write *w = bio->bi_private;
 727
 728         cache_set_err_on(bio->bi_status, w->c, "journal io error");
 729         closure_put(&w->c->journal.io);
 730 }
 731
 732 static void journal_write(struct closure *cl);
 733
 734 static void journal_write_done(struct closure *cl)
 735 {
 736         struct journal *j = container_of(cl, struct journal, io);
 737         struct journal_write *w = (j->cur == j->w)
 738                 ? &j->w[1]
 739                 : &j->w[0];
 740
 741         __closure_wake_up(&w->wait);
 742         continue_at_nobarrier(cl, journal_write, bch_journal_wq);
 743 }
 744
 745 static void journal_write_unlock(struct closure *cl)
 746         __releases(&c->journal.lock)
 747 {
 748         struct cache_set *c = container_of(cl, struct cache_set, journal.io);
 749
 750         c->journal.io_in_flight = 0;
 751         spin_unlock(&c->journal.lock);
 752 }
 753
 754 static void journal_write_unlocked(struct closure *cl)
 755         __releases(c->journal.lock)
 756 {
 757         struct cache_set *c = container_of(cl, struct cache_set, journal.io);
 758         struct cache *ca;
 759         struct journal_write *w = c->journal.cur;
 760         struct bkey *k = &c->journal.key;
 761         unsigned int i, sectors = set_blocks(w->data, block_bytes(c)) *
 762                 c->sb.block_size;
 763
 764         struct bio *bio;
 765         struct bio_list list;
 766
 767         bio_list_init(&list);
 768
 769         if (!w->need_write) {
 770                 closure_return_with_destructor(cl, journal_write_unlock);
 771                 return;
 772         } else if (journal_full(&c->journal)) {
 773                 journal_reclaim(c);
 774                 spin_unlock(&c->journal.lock);
 775
 776                 btree_flush_write(c);
 777                 continue_at(cl, journal_write, bch_journal_wq);
 778                 return;
 779         }
 780
 781         c->journal.blocks_free -= set_blocks(w->data, block_bytes(c));
 782
 783         w->data->btree_level = c->root->level;
 784
 785         bkey_copy(&w->data->btree_root, &c->root->key);
 786         bkey_copy(&w->data->uuid_bucket, &c->uuid_bucket);
 787
 788         for_each_cache(ca, c, i)
 789                 w->data->prio_bucket[ca->sb.nr_this_dev] = ca->prio_buckets[0];
 790
 791         w->data->magic          = jset_magic(&c->sb);
 792         w->data->version        = BCACHE_JSET_VERSION;
 793         w->data->last_seq       = last_seq(&c->journal);
 794         w->data->csum           = csum_set(w->data);
 795
 796         for (i = 0; i < KEY_PTRS(k); i++) {
 797                 ca = PTR_CACHE(c, k, i);
 798                 bio = &ca->journal.bio;
 799
 800                 atomic_long_add(sectors, &ca->meta_sectors_written);
 801
 802                 bio_reset(bio);
 803                 bio->bi_iter.bi_sector  = PTR_OFFSET(k, i);
 804                 bio_set_dev(bio, ca->bdev);
 805                 bio->bi_iter.bi_size = sectors << 9;
 806
 807                 bio->bi_end_io  = journal_write_endio;
 808                 bio->bi_private = w;
 809                 bio_set_op_attrs(bio, REQ_OP_WRITE,
 810                                  REQ_SYNC|REQ_META|REQ_PREFLUSH|REQ_FUA);
 811                 bch_bio_map(bio, w->data);
 812
 813                 trace_bcache_journal_write(bio, w->data->keys);
 814                 bio_list_add(&list, bio);
 815
 816                 SET_PTR_OFFSET(k, i, PTR_OFFSET(k, i) + sectors);
 817
 818                 ca->journal.seq[ca->journal.cur_idx] = w->data->seq;
 819         }
 820
 821         /* If KEY_PTRS(k) == 0, this jset gets lost in air */
 822         BUG_ON(i == 0);
 823
 824         atomic_dec_bug(&fifo_back(&c->journal.pin));
 825         bch_journal_next(&c->journal);
 826         journal_reclaim(c);
 827
 828         spin_unlock(&c->journal.lock);
 829
 830         while ((bio = bio_list_pop(&list)))
 831                 closure_bio_submit(c, bio, cl);
 832
 833         continue_at(cl, journal_write_done, NULL);
 834 }
 835
 836 static void journal_write(struct closure *cl)
 837 {
 838         struct cache_set *c = container_of(cl, struct cache_set, journal.io);
 839
 840         spin_lock(&c->journal.lock);
 841         journal_write_unlocked(cl);
 842 }
 843
 844 static void journal_try_write(struct cache_set *c)
 845         __releases(c->journal.lock)
 846 {
 847         struct closure *cl = &c->journal.io;
 848         struct journal_write *w = c->journal.cur;
 849
 850         w->need_write = true;
 851
 852         if (!c->journal.io_in_flight) {
 853                 c->journal.io_in_flight = 1;
 854                 closure_call(cl, journal_write_unlocked, NULL, &c->cl);
 855         } else {
 856                 spin_unlock(&c->journal.lock);
 857         }
 858 }
 859
 860 static struct journal_write *journal_wait_for_write(struct cache_set *c,
 861                                                     unsigned int nkeys)
 862         __acquires(&c->journal.lock)
 863 {
 864         size_t sectors;
 865         struct closure cl;
 866         bool wait = false;
 867
 868         closure_init_stack(&cl);
 869
 870         spin_lock(&c->journal.lock);
 871
 872         while (1) {
 873                 struct journal_write *w = c->journal.cur;
 874
 875                 sectors = __set_blocks(w->data, w->data->keys + nkeys,
 876                                        block_bytes(c)) * c->sb.block_size;
 877
 878                 if (sectors <= min_t(size_t,
 879                                      c->journal.blocks_free * c->sb.block_size,
 880                                      PAGE_SECTORS << JSET_BITS))
 881                         return w;
 882
 883                 if (wait)
 884                         closure_wait(&c->journal.wait, &cl);
 885
 886                 if (!journal_full(&c->journal)) {
 887                         if (wait)
 888                                 trace_bcache_journal_entry_full(c);
 889
 890                         /*
 891                          * XXX: If we were inserting so many keys that they
 892                          * won't fit in an _empty_ journal write, we'll
 893                          * deadlock. For now, handle this in
 894                          * bch_keylist_realloc() - but something to think about.
 895                          */
 896                         BUG_ON(!w->data->keys);
 897
 898                         journal_try_write(c); /* unlocks */
 899                 } else {
 900                         if (wait)
 901                                 trace_bcache_journal_full(c);
 902
 903                         journal_reclaim(c);
 904                         spin_unlock(&c->journal.lock);
 905
 906                         btree_flush_write(c);
 907                 }
 908
 909                 closure_sync(&cl);
 910                 spin_lock(&c->journal.lock);
 911                 wait = true;
 912         }
 913 }
 914
 915 static void journal_write_work(struct work_struct *work)
 916 {
 917         struct cache_set *c = container_of(to_delayed_work(work),
 918                                            struct cache_set,
 919                                            journal.work);
 920         spin_lock(&c->journal.lock);
 921         if (c->journal.cur->dirty)
 922                 journal_try_write(c);
 923         else
 924                 spin_unlock(&c->journal.lock);
 925 }
 926
 927 /*
 928  * Entry point to the journalling code - bio_insert() and btree_invalidate()
 929  * pass bch_journal() a list of keys to be journalled, and then
 930  * bch_journal() hands those same keys off to btree_insert_async()
 931  */
 932
 933 atomic_t *bch_journal(struct cache_set *c,
 934                       struct keylist *keys,
 935                       struct closure *parent)
 936 {
 937         struct journal_write *w;
 938         atomic_t *ret;
 939
 940         /* No journaling if CACHE_SET_IO_DISABLE set already */
 941         if (unlikely(test_bit(CACHE_SET_IO_DISABLE, &c->flags)))
 942                 return NULL;
 943
 944         if (!CACHE_SYNC(&c->sb))
 945                 return NULL;
 946
 947         w = journal_wait_for_write(c, bch_keylist_nkeys(keys));
 948
 949         memcpy(bset_bkey_last(w->data), keys->keys, bch_keylist_bytes(keys));
 950         w->data->keys += bch_keylist_nkeys(keys);
 951
 952         ret = &fifo_back(&c->journal.pin);
 953         atomic_inc(ret);
 954
 955         if (parent) {
 956                 closure_wait(&w->wait, parent);
 957                 journal_try_write(c);
 958         } else if (!w->dirty) {
 959                 w->dirty = true;
 960                 schedule_delayed_work(&c->journal.work,
 961                                       msecs_to_jiffies(c->journal_delay_ms));
 962                 spin_unlock(&c->journal.lock);
 963         } else {
 964                 spin_unlock(&c->journal.lock);
 965         }
 966
 967
 968         return ret;
 969 }
 970
 971 void bch_journal_meta(struct cache_set *c, struct closure *cl)
 972 {
 973         struct keylist keys;
 974         atomic_t *ref;
 975
 976         bch_keylist_init(&keys);
 977
 978         ref = bch_journal(c, &keys, cl);
 979         if (ref)
 980                 atomic_dec_bug(ref);
 981 }
 982
 983 void bch_journal_free(struct cache_set *c)
 984 {
 985         free_pages((unsigned long) c->journal.w[1].data, JSET_BITS);
 986         free_pages((unsigned long) c->journal.w[0].data, JSET_BITS);
 987         free_fifo(&c->journal.pin);
 988 }
 989
 990 int bch_journal_alloc(struct cache_set *c)
 991 {
 992         struct journal *j = &c->journal;
 993
 994         spin_lock_init(&j->lock);
 995         spin_lock_init(&j->flush_write_lock);
 996         INIT_DELAYED_WORK(&j->work, journal_write_work);
 997
 998         c->journal_delay_ms = 100;
 999
1000         j->w[0].c = c;
1001         j->w[1].c = c;
1002
1003         if (!(init_fifo(&j->pin, JOURNAL_PIN, GFP_KERNEL)) ||
1004             !(j->w[0].data = (void *) __get_free_pages(GFP_KERNEL, JSET_BITS)) ||
1005             !(j->w[1].data = (void *) __get_free_pages(GFP_KERNEL, JSET_BITS)))
1006                 return -ENOMEM;
1007
1008         return 0;
1009 }