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