git.sesse.net Git - bcachefs-tools-debian/blob - c_src/libbcachefs/journal_reclaim.c

   1 // SPDX-License-Identifier: GPL-2.0
   2
   3 #include "bcachefs.h"
   4 #include "btree_key_cache.h"
   5 #include "btree_update.h"
   6 #include "btree_write_buffer.h"
   7 #include "buckets.h"
   8 #include "errcode.h"
   9 #include "error.h"
  10 #include "journal.h"
  11 #include "journal_io.h"
  12 #include "journal_reclaim.h"
  13 #include "replicas.h"
  14 #include "sb-members.h"
  15 #include "trace.h"
  16
  17 #include <linux/kthread.h>
  18 #include <linux/sched/mm.h>
  19
  20 /* Free space calculations: */
  21
  22 static unsigned journal_space_from(struct journal_device *ja,
  23                                    enum journal_space_from from)
  24 {
  25         switch (from) {
  26         case journal_space_discarded:
  27                 return ja->discard_idx;
  28         case journal_space_clean_ondisk:
  29                 return ja->dirty_idx_ondisk;
  30         case journal_space_clean:
  31                 return ja->dirty_idx;
  32         default:
  33                 BUG();
  34         }
  35 }
  36
  37 unsigned bch2_journal_dev_buckets_available(struct journal *j,
  38                                             struct journal_device *ja,
  39                                             enum journal_space_from from)
  40 {
  41         unsigned available = (journal_space_from(ja, from) -
  42                               ja->cur_idx - 1 + ja->nr) % ja->nr;
  43
  44         /*
  45          * Don't use the last bucket unless writing the new last_seq
  46          * will make another bucket available:
  47          */
  48         if (available && ja->dirty_idx_ondisk == ja->dirty_idx)
  49                 --available;
  50
  51         return available;
  52 }
  53
  54 void bch2_journal_set_watermark(struct journal *j)
  55 {
  56         struct bch_fs *c = container_of(j, struct bch_fs, journal);
  57         bool low_on_space = j->space[journal_space_clean].total * 4 <=
  58                 j->space[journal_space_total].total;
  59         bool low_on_pin = fifo_free(&j->pin) < j->pin.size / 4;
  60         bool low_on_wb = bch2_btree_write_buffer_must_wait(c);
  61         unsigned watermark = low_on_space || low_on_pin || low_on_wb
  62                 ? BCH_WATERMARK_reclaim
  63                 : BCH_WATERMARK_stripe;
  64
  65         if (track_event_change(&c->times[BCH_TIME_blocked_journal_low_on_space],
  66                                &j->low_on_space_start, low_on_space) ||
  67             track_event_change(&c->times[BCH_TIME_blocked_journal_low_on_pin],
  68                                &j->low_on_pin_start, low_on_pin) ||
  69             track_event_change(&c->times[BCH_TIME_blocked_write_buffer_full],
  70                                &j->write_buffer_full_start, low_on_wb))
  71                 trace_and_count(c, journal_full, c);
  72
  73         swap(watermark, j->watermark);
  74         if (watermark > j->watermark)
  75                 journal_wake(j);
  76 }
  77
  78 static struct journal_space
  79 journal_dev_space_available(struct journal *j, struct bch_dev *ca,
  80                             enum journal_space_from from)
  81 {
  82         struct journal_device *ja = &ca->journal;
  83         unsigned sectors, buckets, unwritten;
  84         u64 seq;
  85
  86         if (from == journal_space_total)
  87                 return (struct journal_space) {
  88                         .next_entry     = ca->mi.bucket_size,
  89                         .total          = ca->mi.bucket_size * ja->nr,
  90                 };
  91
  92         buckets = bch2_journal_dev_buckets_available(j, ja, from);
  93         sectors = ja->sectors_free;
  94
  95         /*
  96          * We that we don't allocate the space for a journal entry
  97          * until we write it out - thus, account for it here:
  98          */
  99         for (seq = journal_last_unwritten_seq(j);
 100              seq <= journal_cur_seq(j);
 101              seq++) {
 102                 unwritten = j->buf[seq & JOURNAL_BUF_MASK].sectors;
 103
 104                 if (!unwritten)
 105                         continue;
 106
 107                 /* entry won't fit on this device, skip: */
 108                 if (unwritten > ca->mi.bucket_size)
 109                         continue;
 110
 111                 if (unwritten >= sectors) {
 112                         if (!buckets) {
 113                                 sectors = 0;
 114                                 break;
 115                         }
 116
 117                         buckets--;
 118                         sectors = ca->mi.bucket_size;
 119                 }
 120
 121                 sectors -= unwritten;
 122         }
 123
 124         if (sectors < ca->mi.bucket_size && buckets) {
 125                 buckets--;
 126                 sectors = ca->mi.bucket_size;
 127         }
 128
 129         return (struct journal_space) {
 130                 .next_entry     = sectors,
 131                 .total          = sectors + buckets * ca->mi.bucket_size,
 132         };
 133 }
 134
 135 static struct journal_space __journal_space_available(struct journal *j, unsigned nr_devs_want,
 136                             enum journal_space_from from)
 137 {
 138         struct bch_fs *c = container_of(j, struct bch_fs, journal);
 139         unsigned pos, nr_devs = 0;
 140         struct journal_space space, dev_space[BCH_SB_MEMBERS_MAX];
 141
 142         BUG_ON(nr_devs_want > ARRAY_SIZE(dev_space));
 143
 144         rcu_read_lock();
 145         for_each_member_device_rcu(c, ca, &c->rw_devs[BCH_DATA_journal]) {
 146                 if (!ca->journal.nr)
 147                         continue;
 148
 149                 space = journal_dev_space_available(j, ca, from);
 150                 if (!space.next_entry)
 151                         continue;
 152
 153                 for (pos = 0; pos < nr_devs; pos++)
 154                         if (space.total > dev_space[pos].total)
 155                                 break;
 156
 157                 array_insert_item(dev_space, nr_devs, pos, space);
 158         }
 159         rcu_read_unlock();
 160
 161         if (nr_devs < nr_devs_want)
 162                 return (struct journal_space) { 0, 0 };
 163
 164         /*
 165          * We sorted largest to smallest, and we want the smallest out of the
 166          * @nr_devs_want largest devices:
 167          */
 168         return dev_space[nr_devs_want - 1];
 169 }
 170
 171 void bch2_journal_space_available(struct journal *j)
 172 {
 173         struct bch_fs *c = container_of(j, struct bch_fs, journal);
 174         unsigned clean, clean_ondisk, total;
 175         unsigned max_entry_size  = min(j->buf[0].buf_size >> 9,
 176                                        j->buf[1].buf_size >> 9);
 177         unsigned nr_online = 0, nr_devs_want;
 178         bool can_discard = false;
 179         int ret = 0;
 180
 181         lockdep_assert_held(&j->lock);
 182
 183         rcu_read_lock();
 184         for_each_member_device_rcu(c, ca, &c->rw_devs[BCH_DATA_journal]) {
 185                 struct journal_device *ja = &ca->journal;
 186
 187                 if (!ja->nr)
 188                         continue;
 189
 190                 while (ja->dirty_idx != ja->cur_idx &&
 191                        ja->bucket_seq[ja->dirty_idx] < journal_last_seq(j))
 192                         ja->dirty_idx = (ja->dirty_idx + 1) % ja->nr;
 193
 194                 while (ja->dirty_idx_ondisk != ja->dirty_idx &&
 195                        ja->bucket_seq[ja->dirty_idx_ondisk] < j->last_seq_ondisk)
 196                         ja->dirty_idx_ondisk = (ja->dirty_idx_ondisk + 1) % ja->nr;
 197
 198                 if (ja->discard_idx != ja->dirty_idx_ondisk)
 199                         can_discard = true;
 200
 201                 max_entry_size = min_t(unsigned, max_entry_size, ca->mi.bucket_size);
 202                 nr_online++;
 203         }
 204         rcu_read_unlock();
 205
 206         j->can_discard = can_discard;
 207
 208         if (nr_online < c->opts.metadata_replicas_required) {
 209                 ret = JOURNAL_ERR_insufficient_devices;
 210                 goto out;
 211         }
 212
 213         nr_devs_want = min_t(unsigned, nr_online, c->opts.metadata_replicas);
 214
 215         for (unsigned i = 0; i < journal_space_nr; i++)
 216                 j->space[i] = __journal_space_available(j, nr_devs_want, i);
 217
 218         clean_ondisk    = j->space[journal_space_clean_ondisk].total;
 219         clean           = j->space[journal_space_clean].total;
 220         total           = j->space[journal_space_total].total;
 221
 222         if (!j->space[journal_space_discarded].next_entry)
 223                 ret = JOURNAL_ERR_journal_full;
 224
 225         if ((j->space[journal_space_clean_ondisk].next_entry <
 226              j->space[journal_space_clean_ondisk].total) &&
 227             (clean - clean_ondisk <= total / 8) &&
 228             (clean_ondisk * 2 > clean))
 229                 set_bit(JOURNAL_MAY_SKIP_FLUSH, &j->flags);
 230         else
 231                 clear_bit(JOURNAL_MAY_SKIP_FLUSH, &j->flags);
 232
 233         bch2_journal_set_watermark(j);
 234 out:
 235         j->cur_entry_sectors    = !ret ? j->space[journal_space_discarded].next_entry : 0;
 236         j->cur_entry_error      = ret;
 237
 238         if (!ret)
 239                 journal_wake(j);
 240 }
 241
 242 /* Discards - last part of journal reclaim: */
 243
 244 static bool should_discard_bucket(struct journal *j, struct journal_device *ja)
 245 {
 246         bool ret;
 247
 248         spin_lock(&j->lock);
 249         ret = ja->discard_idx != ja->dirty_idx_ondisk;
 250         spin_unlock(&j->lock);
 251
 252         return ret;
 253 }
 254
 255 /*
 256  * Advance ja->discard_idx as long as it points to buckets that are no longer
 257  * dirty, issuing discards if necessary:
 258  */
 259 void bch2_journal_do_discards(struct journal *j)
 260 {
 261         struct bch_fs *c = container_of(j, struct bch_fs, journal);
 262
 263         mutex_lock(&j->discard_lock);
 264
 265         for_each_rw_member(c, ca) {
 266                 struct journal_device *ja = &ca->journal;
 267
 268                 while (should_discard_bucket(j, ja)) {
 269                         if (!c->opts.nochanges &&
 270                             ca->mi.discard &&
 271                             bdev_max_discard_sectors(ca->disk_sb.bdev))
 272                                 blkdev_issue_discard(ca->disk_sb.bdev,
 273                                         bucket_to_sector(ca,
 274                                                 ja->buckets[ja->discard_idx]),
 275                                         ca->mi.bucket_size, GFP_NOFS);
 276
 277                         spin_lock(&j->lock);
 278                         ja->discard_idx = (ja->discard_idx + 1) % ja->nr;
 279
 280                         bch2_journal_space_available(j);
 281                         spin_unlock(&j->lock);
 282                 }
 283         }
 284
 285         mutex_unlock(&j->discard_lock);
 286 }
 287
 288 /*
 289  * Journal entry pinning - machinery for holding a reference on a given journal
 290  * entry, holding it open to ensure it gets replayed during recovery:
 291  */
 292
 293 void bch2_journal_reclaim_fast(struct journal *j)
 294 {
 295         bool popped = false;
 296
 297         lockdep_assert_held(&j->lock);
 298
 299         /*
 300          * Unpin journal entries whose reference counts reached zero, meaning
 301          * all btree nodes got written out
 302          */
 303         while (!fifo_empty(&j->pin) &&
 304                j->pin.front <= j->seq_ondisk &&
 305                !atomic_read(&fifo_peek_front(&j->pin).count)) {
 306                 j->pin.front++;
 307                 popped = true;
 308         }
 309
 310         if (popped)
 311                 bch2_journal_space_available(j);
 312 }
 313
 314 bool __bch2_journal_pin_put(struct journal *j, u64 seq)
 315 {
 316         struct journal_entry_pin_list *pin_list = journal_seq_pin(j, seq);
 317
 318         return atomic_dec_and_test(&pin_list->count);
 319 }
 320
 321 void bch2_journal_pin_put(struct journal *j, u64 seq)
 322 {
 323         if (__bch2_journal_pin_put(j, seq)) {
 324                 spin_lock(&j->lock);
 325                 bch2_journal_reclaim_fast(j);
 326                 spin_unlock(&j->lock);
 327         }
 328 }
 329
 330 static inline bool __journal_pin_drop(struct journal *j,
 331                                       struct journal_entry_pin *pin)
 332 {
 333         struct journal_entry_pin_list *pin_list;
 334
 335         if (!journal_pin_active(pin))
 336                 return false;
 337
 338         if (j->flush_in_progress == pin)
 339                 j->flush_in_progress_dropped = true;
 340
 341         pin_list = journal_seq_pin(j, pin->seq);
 342         pin->seq = 0;
 343         list_del_init(&pin->list);
 344
 345         /*
 346          * Unpinning a journal entry may make journal_next_bucket() succeed, if
 347          * writing a new last_seq will now make another bucket available:
 348          */
 349         return atomic_dec_and_test(&pin_list->count) &&
 350                 pin_list == &fifo_peek_front(&j->pin);
 351 }
 352
 353 void bch2_journal_pin_drop(struct journal *j,
 354                            struct journal_entry_pin *pin)
 355 {
 356         spin_lock(&j->lock);
 357         if (__journal_pin_drop(j, pin))
 358                 bch2_journal_reclaim_fast(j);
 359         spin_unlock(&j->lock);
 360 }
 361
 362 static enum journal_pin_type journal_pin_type(journal_pin_flush_fn fn)
 363 {
 364         if (fn == bch2_btree_node_flush0 ||
 365             fn == bch2_btree_node_flush1)
 366                 return JOURNAL_PIN_btree;
 367         else if (fn == bch2_btree_key_cache_journal_flush)
 368                 return JOURNAL_PIN_key_cache;
 369         else
 370                 return JOURNAL_PIN_other;
 371 }
 372
 373 static inline void bch2_journal_pin_set_locked(struct journal *j, u64 seq,
 374                           struct journal_entry_pin *pin,
 375                           journal_pin_flush_fn flush_fn,
 376                           enum journal_pin_type type)
 377 {
 378         struct journal_entry_pin_list *pin_list = journal_seq_pin(j, seq);
 379
 380         /*
 381          * flush_fn is how we identify journal pins in debugfs, so must always
 382          * exist, even if it doesn't do anything:
 383          */
 384         BUG_ON(!flush_fn);
 385
 386         atomic_inc(&pin_list->count);
 387         pin->seq        = seq;
 388         pin->flush      = flush_fn;
 389         list_add(&pin->list, &pin_list->list[type]);
 390 }
 391
 392 void bch2_journal_pin_copy(struct journal *j,
 393                            struct journal_entry_pin *dst,
 394                            struct journal_entry_pin *src,
 395                            journal_pin_flush_fn flush_fn)
 396 {
 397         bool reclaim;
 398
 399         spin_lock(&j->lock);
 400
 401         u64 seq = READ_ONCE(src->seq);
 402
 403         if (seq < journal_last_seq(j)) {
 404                 /*
 405                  * bch2_journal_pin_copy() raced with bch2_journal_pin_drop() on
 406                  * the src pin - with the pin dropped, the entry to pin might no
 407                  * longer to exist, but that means there's no longer anything to
 408                  * copy and we can bail out here:
 409                  */
 410                 spin_unlock(&j->lock);
 411                 return;
 412         }
 413
 414         reclaim = __journal_pin_drop(j, dst);
 415
 416         bch2_journal_pin_set_locked(j, seq, dst, flush_fn, journal_pin_type(flush_fn));
 417
 418         if (reclaim)
 419                 bch2_journal_reclaim_fast(j);
 420         spin_unlock(&j->lock);
 421
 422         /*
 423          * If the journal is currently full,  we might want to call flush_fn
 424          * immediately:
 425          */
 426         journal_wake(j);
 427 }
 428
 429 void bch2_journal_pin_set(struct journal *j, u64 seq,
 430                           struct journal_entry_pin *pin,
 431                           journal_pin_flush_fn flush_fn)
 432 {
 433         bool reclaim;
 434
 435         spin_lock(&j->lock);
 436
 437         BUG_ON(seq < journal_last_seq(j));
 438
 439         reclaim = __journal_pin_drop(j, pin);
 440
 441         bch2_journal_pin_set_locked(j, seq, pin, flush_fn, journal_pin_type(flush_fn));
 442
 443         if (reclaim)
 444                 bch2_journal_reclaim_fast(j);
 445         spin_unlock(&j->lock);
 446
 447         /*
 448          * If the journal is currently full,  we might want to call flush_fn
 449          * immediately:
 450          */
 451         journal_wake(j);
 452 }
 453
 454 /**
 455  * bch2_journal_pin_flush: ensure journal pin callback is no longer running
 456  * @j:          journal object
 457  * @pin:        pin to flush
 458  */
 459 void bch2_journal_pin_flush(struct journal *j, struct journal_entry_pin *pin)
 460 {
 461         BUG_ON(journal_pin_active(pin));
 462
 463         wait_event(j->pin_flush_wait, j->flush_in_progress != pin);
 464 }
 465
 466 /*
 467  * Journal reclaim: flush references to open journal entries to reclaim space in
 468  * the journal
 469  *
 470  * May be done by the journal code in the background as needed to free up space
 471  * for more journal entries, or as part of doing a clean shutdown, or to migrate
 472  * data off of a specific device:
 473  */
 474
 475 static struct journal_entry_pin *
 476 journal_get_next_pin(struct journal *j,
 477                      u64 seq_to_flush,
 478                      unsigned allowed_below_seq,
 479                      unsigned allowed_above_seq,
 480                      u64 *seq)
 481 {
 482         struct journal_entry_pin_list *pin_list;
 483         struct journal_entry_pin *ret = NULL;
 484         unsigned i;
 485
 486         fifo_for_each_entry_ptr(pin_list, &j->pin, *seq) {
 487                 if (*seq > seq_to_flush && !allowed_above_seq)
 488                         break;
 489
 490                 for (i = 0; i < JOURNAL_PIN_NR; i++)
 491                         if ((((1U << i) & allowed_below_seq) && *seq <= seq_to_flush) ||
 492                             ((1U << i) & allowed_above_seq)) {
 493                                 ret = list_first_entry_or_null(&pin_list->list[i],
 494                                         struct journal_entry_pin, list);
 495                                 if (ret)
 496                                         return ret;
 497                         }
 498         }
 499
 500         return NULL;
 501 }
 502
 503 /* returns true if we did work */
 504 static size_t journal_flush_pins(struct journal *j,
 505                                  u64 seq_to_flush,
 506                                  unsigned allowed_below_seq,
 507                                  unsigned allowed_above_seq,
 508                                  unsigned min_any,
 509                                  unsigned min_key_cache)
 510 {
 511         struct journal_entry_pin *pin;
 512         size_t nr_flushed = 0;
 513         journal_pin_flush_fn flush_fn;
 514         u64 seq;
 515         int err;
 516
 517         lockdep_assert_held(&j->reclaim_lock);
 518
 519         while (1) {
 520                 unsigned allowed_above = allowed_above_seq;
 521                 unsigned allowed_below = allowed_below_seq;
 522
 523                 if (min_any) {
 524                         allowed_above |= ~0;
 525                         allowed_below |= ~0;
 526                 }
 527
 528                 if (min_key_cache) {
 529                         allowed_above |= 1U << JOURNAL_PIN_key_cache;
 530                         allowed_below |= 1U << JOURNAL_PIN_key_cache;
 531                 }
 532
 533                 cond_resched();
 534
 535                 j->last_flushed = jiffies;
 536
 537                 spin_lock(&j->lock);
 538                 pin = journal_get_next_pin(j, seq_to_flush, allowed_below, allowed_above, &seq);
 539                 if (pin) {
 540                         BUG_ON(j->flush_in_progress);
 541                         j->flush_in_progress = pin;
 542                         j->flush_in_progress_dropped = false;
 543                         flush_fn = pin->flush;
 544                 }
 545                 spin_unlock(&j->lock);
 546
 547                 if (!pin)
 548                         break;
 549
 550                 if (min_key_cache && pin->flush == bch2_btree_key_cache_journal_flush)
 551                         min_key_cache--;
 552
 553                 if (min_any)
 554                         min_any--;
 555
 556                 err = flush_fn(j, pin, seq);
 557
 558                 spin_lock(&j->lock);
 559                 /* Pin might have been dropped or rearmed: */
 560                 if (likely(!err && !j->flush_in_progress_dropped))
 561                         list_move(&pin->list, &journal_seq_pin(j, seq)->flushed);
 562                 j->flush_in_progress = NULL;
 563                 j->flush_in_progress_dropped = false;
 564                 spin_unlock(&j->lock);
 565
 566                 wake_up(&j->pin_flush_wait);
 567
 568                 if (err)
 569                         break;
 570
 571                 nr_flushed++;
 572         }
 573
 574         return nr_flushed;
 575 }
 576
 577 static u64 journal_seq_to_flush(struct journal *j)
 578 {
 579         struct bch_fs *c = container_of(j, struct bch_fs, journal);
 580         u64 seq_to_flush = 0;
 581
 582         spin_lock(&j->lock);
 583
 584         for_each_rw_member(c, ca) {
 585                 struct journal_device *ja = &ca->journal;
 586                 unsigned nr_buckets, bucket_to_flush;
 587
 588                 if (!ja->nr)
 589                         continue;
 590
 591                 /* Try to keep the journal at most half full: */
 592                 nr_buckets = ja->nr / 2;
 593
 594                 nr_buckets = min(nr_buckets, ja->nr);
 595
 596                 bucket_to_flush = (ja->cur_idx + nr_buckets) % ja->nr;
 597                 seq_to_flush = max(seq_to_flush,
 598                                    ja->bucket_seq[bucket_to_flush]);
 599         }
 600
 601         /* Also flush if the pin fifo is more than half full */
 602         seq_to_flush = max_t(s64, seq_to_flush,
 603                              (s64) journal_cur_seq(j) -
 604                              (j->pin.size >> 1));
 605         spin_unlock(&j->lock);
 606
 607         return seq_to_flush;
 608 }
 609
 610 /**
 611  * __bch2_journal_reclaim - free up journal buckets
 612  * @j:          journal object
 613  * @direct:     direct or background reclaim?
 614  * @kicked:     requested to run since we last ran?
 615  * Returns:     0 on success, or -EIO if the journal has been shutdown
 616  *
 617  * Background journal reclaim writes out btree nodes. It should be run
 618  * early enough so that we never completely run out of journal buckets.
 619  *
 620  * High watermarks for triggering background reclaim:
 621  * - FIFO has fewer than 512 entries left
 622  * - fewer than 25% journal buckets free
 623  *
 624  * Background reclaim runs until low watermarks are reached:
 625  * - FIFO has more than 1024 entries left
 626  * - more than 50% journal buckets free
 627  *
 628  * As long as a reclaim can complete in the time it takes to fill up
 629  * 512 journal entries or 25% of all journal buckets, then
 630  * journal_next_bucket() should not stall.
 631  */
 632 static int __bch2_journal_reclaim(struct journal *j, bool direct, bool kicked)
 633 {
 634         struct bch_fs *c = container_of(j, struct bch_fs, journal);
 635         bool kthread = (current->flags & PF_KTHREAD) != 0;
 636         u64 seq_to_flush;
 637         size_t min_nr, min_key_cache, nr_flushed;
 638         unsigned flags;
 639         int ret = 0;
 640
 641         /*
 642          * We can't invoke memory reclaim while holding the reclaim_lock -
 643          * journal reclaim is required to make progress for memory reclaim
 644          * (cleaning the caches), so we can't get stuck in memory reclaim while
 645          * we're holding the reclaim lock:
 646          */
 647         lockdep_assert_held(&j->reclaim_lock);
 648         flags = memalloc_noreclaim_save();
 649
 650         do {
 651                 if (kthread && kthread_should_stop())
 652                         break;
 653
 654                 if (bch2_journal_error(j)) {
 655                         ret = -EIO;
 656                         break;
 657                 }
 658
 659                 bch2_journal_do_discards(j);
 660
 661                 seq_to_flush = journal_seq_to_flush(j);
 662                 min_nr = 0;
 663
 664                 /*
 665                  * If it's been longer than j->reclaim_delay_ms since we last flushed,
 666                  * make sure to flush at least one journal pin:
 667                  */
 668                 if (time_after(jiffies, j->last_flushed +
 669                                msecs_to_jiffies(c->opts.journal_reclaim_delay)))
 670                         min_nr = 1;
 671
 672                 if (j->watermark != BCH_WATERMARK_stripe)
 673                         min_nr = 1;
 674
 675                 if (atomic_read(&c->btree_cache.dirty) * 2 > c->btree_cache.used)
 676                         min_nr = 1;
 677
 678                 min_key_cache = min(bch2_nr_btree_keys_need_flush(c), (size_t) 128);
 679
 680                 trace_and_count(c, journal_reclaim_start, c,
 681                                 direct, kicked,
 682                                 min_nr, min_key_cache,
 683                                 atomic_read(&c->btree_cache.dirty),
 684                                 c->btree_cache.used,
 685                                 atomic_long_read(&c->btree_key_cache.nr_dirty),
 686                                 atomic_long_read(&c->btree_key_cache.nr_keys));
 687
 688                 nr_flushed = journal_flush_pins(j, seq_to_flush,
 689                                                 ~0, 0,
 690                                                 min_nr, min_key_cache);
 691
 692                 if (direct)
 693                         j->nr_direct_reclaim += nr_flushed;
 694                 else
 695                         j->nr_background_reclaim += nr_flushed;
 696                 trace_and_count(c, journal_reclaim_finish, c, nr_flushed);
 697
 698                 if (nr_flushed)
 699                         wake_up(&j->reclaim_wait);
 700         } while ((min_nr || min_key_cache) && nr_flushed && !direct);
 701
 702         memalloc_noreclaim_restore(flags);
 703
 704         return ret;
 705 }
 706
 707 int bch2_journal_reclaim(struct journal *j)
 708 {
 709         return __bch2_journal_reclaim(j, true, true);
 710 }
 711
 712 static int bch2_journal_reclaim_thread(void *arg)
 713 {
 714         struct journal *j = arg;
 715         struct bch_fs *c = container_of(j, struct bch_fs, journal);
 716         unsigned long delay, now;
 717         bool journal_empty;
 718         int ret = 0;
 719
 720         set_freezable();
 721
 722         j->last_flushed = jiffies;
 723
 724         while (!ret && !kthread_should_stop()) {
 725                 bool kicked = j->reclaim_kicked;
 726
 727                 j->reclaim_kicked = false;
 728
 729                 mutex_lock(&j->reclaim_lock);
 730                 ret = __bch2_journal_reclaim(j, false, kicked);
 731                 mutex_unlock(&j->reclaim_lock);
 732
 733                 now = jiffies;
 734                 delay = msecs_to_jiffies(c->opts.journal_reclaim_delay);
 735                 j->next_reclaim = j->last_flushed + delay;
 736
 737                 if (!time_in_range(j->next_reclaim, now, now + delay))
 738                         j->next_reclaim = now + delay;
 739
 740                 while (1) {
 741                         set_current_state(TASK_INTERRUPTIBLE|TASK_FREEZABLE);
 742                         if (kthread_should_stop())
 743                                 break;
 744                         if (j->reclaim_kicked)
 745                                 break;
 746
 747                         spin_lock(&j->lock);
 748                         journal_empty = fifo_empty(&j->pin);
 749                         spin_unlock(&j->lock);
 750
 751                         if (journal_empty)
 752                                 schedule();
 753                         else if (time_after(j->next_reclaim, jiffies))
 754                                 schedule_timeout(j->next_reclaim - jiffies);
 755                         else
 756                                 break;
 757                 }
 758                 __set_current_state(TASK_RUNNING);
 759         }
 760
 761         return 0;
 762 }
 763
 764 void bch2_journal_reclaim_stop(struct journal *j)
 765 {
 766         struct task_struct *p = j->reclaim_thread;
 767
 768         j->reclaim_thread = NULL;
 769
 770         if (p) {
 771                 kthread_stop(p);
 772                 put_task_struct(p);
 773         }
 774 }
 775
 776 int bch2_journal_reclaim_start(struct journal *j)
 777 {
 778         struct bch_fs *c = container_of(j, struct bch_fs, journal);
 779         struct task_struct *p;
 780         int ret;
 781
 782         if (j->reclaim_thread)
 783                 return 0;
 784
 785         p = kthread_create(bch2_journal_reclaim_thread, j,
 786                            "bch-reclaim/%s", c->name);
 787         ret = PTR_ERR_OR_ZERO(p);
 788         bch_err_msg(c, ret, "creating journal reclaim thread");
 789         if (ret)
 790                 return ret;
 791
 792         get_task_struct(p);
 793         j->reclaim_thread = p;
 794         wake_up_process(p);
 795         return 0;
 796 }
 797
 798 static int journal_flush_done(struct journal *j, u64 seq_to_flush,
 799                               bool *did_work)
 800 {
 801         int ret;
 802
 803         ret = bch2_journal_error(j);
 804         if (ret)
 805                 return ret;
 806
 807         mutex_lock(&j->reclaim_lock);
 808
 809         if (journal_flush_pins(j, seq_to_flush,
 810                                (1U << JOURNAL_PIN_key_cache)|
 811                                (1U << JOURNAL_PIN_other), 0, 0, 0) ||
 812             journal_flush_pins(j, seq_to_flush,
 813                                (1U << JOURNAL_PIN_btree), 0, 0, 0))
 814                 *did_work = true;
 815
 816         if (seq_to_flush > journal_cur_seq(j))
 817                 bch2_journal_entry_close(j);
 818
 819         spin_lock(&j->lock);
 820         /*
 821          * If journal replay hasn't completed, the unreplayed journal entries
 822          * hold refs on their corresponding sequence numbers
 823          */
 824         ret = !test_bit(JOURNAL_REPLAY_DONE, &j->flags) ||
 825                 journal_last_seq(j) > seq_to_flush ||
 826                 !fifo_used(&j->pin);
 827
 828         spin_unlock(&j->lock);
 829         mutex_unlock(&j->reclaim_lock);
 830
 831         return ret;
 832 }
 833
 834 bool bch2_journal_flush_pins(struct journal *j, u64 seq_to_flush)
 835 {
 836         /* time_stats this */
 837         bool did_work = false;
 838
 839         if (!test_bit(JOURNAL_STARTED, &j->flags))
 840                 return false;
 841
 842         closure_wait_event(&j->async_wait,
 843                 journal_flush_done(j, seq_to_flush, &did_work));
 844
 845         return did_work;
 846 }
 847
 848 int bch2_journal_flush_device_pins(struct journal *j, int dev_idx)
 849 {
 850         struct bch_fs *c = container_of(j, struct bch_fs, journal);
 851         struct journal_entry_pin_list *p;
 852         u64 iter, seq = 0;
 853         int ret = 0;
 854
 855         spin_lock(&j->lock);
 856         fifo_for_each_entry_ptr(p, &j->pin, iter)
 857                 if (dev_idx >= 0
 858                     ? bch2_dev_list_has_dev(p->devs, dev_idx)
 859                     : p->devs.nr < c->opts.metadata_replicas)
 860                         seq = iter;
 861         spin_unlock(&j->lock);
 862
 863         bch2_journal_flush_pins(j, seq);
 864
 865         ret = bch2_journal_error(j);
 866         if (ret)
 867                 return ret;
 868
 869         mutex_lock(&c->replicas_gc_lock);
 870         bch2_replicas_gc_start(c, 1 << BCH_DATA_journal);
 871
 872         /*
 873          * Now that we've populated replicas_gc, write to the journal to mark
 874          * active journal devices. This handles the case where the journal might
 875          * be empty. Otherwise we could clear all journal replicas and
 876          * temporarily put the fs into an unrecoverable state. Journal recovery
 877          * expects to find devices marked for journal data on unclean mount.
 878          */
 879         ret = bch2_journal_meta(&c->journal);
 880         if (ret)
 881                 goto err;
 882
 883         seq = 0;
 884         spin_lock(&j->lock);
 885         while (!ret) {
 886                 struct bch_replicas_padded replicas;
 887
 888                 seq = max(seq, journal_last_seq(j));
 889                 if (seq >= j->pin.back)
 890                         break;
 891                 bch2_devlist_to_replicas(&replicas.e, BCH_DATA_journal,
 892                                          journal_seq_pin(j, seq)->devs);
 893                 seq++;
 894
 895                 spin_unlock(&j->lock);
 896                 ret = bch2_mark_replicas(c, &replicas.e);
 897                 spin_lock(&j->lock);
 898         }
 899         spin_unlock(&j->lock);
 900 err:
 901         ret = bch2_replicas_gc_end(c, ret);
 902         mutex_unlock(&c->replicas_gc_lock);
 903
 904         return ret;
 905 }