git.sesse.net Git - bcachefs-tools-debian/blob - 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         struct bch_dev *ca;
 140         unsigned i, pos, nr_devs = 0;
 141         struct journal_space space, dev_space[BCH_SB_MEMBERS_MAX];
 142
 143         BUG_ON(nr_devs_want > ARRAY_SIZE(dev_space));
 144
 145         rcu_read_lock();
 146         for_each_member_device_rcu(ca, c, i,
 147                                    &c->rw_devs[BCH_DATA_journal]) {
 148                 if (!ca->journal.nr)
 149                         continue;
 150
 151                 space = journal_dev_space_available(j, ca, from);
 152                 if (!space.next_entry)
 153                         continue;
 154
 155                 for (pos = 0; pos < nr_devs; pos++)
 156                         if (space.total > dev_space[pos].total)
 157                                 break;
 158
 159                 array_insert_item(dev_space, nr_devs, pos, space);
 160         }
 161         rcu_read_unlock();
 162
 163         if (nr_devs < nr_devs_want)
 164                 return (struct journal_space) { 0, 0 };
 165
 166         /*
 167          * We sorted largest to smallest, and we want the smallest out of the
 168          * @nr_devs_want largest devices:
 169          */
 170         return dev_space[nr_devs_want - 1];
 171 }
 172
 173 void bch2_journal_space_available(struct journal *j)
 174 {
 175         struct bch_fs *c = container_of(j, struct bch_fs, journal);
 176         struct bch_dev *ca;
 177         unsigned clean, clean_ondisk, total;
 178         unsigned max_entry_size  = min(j->buf[0].buf_size >> 9,
 179                                        j->buf[1].buf_size >> 9);
 180         unsigned i, nr_online = 0, nr_devs_want;
 181         bool can_discard = false;
 182         int ret = 0;
 183
 184         lockdep_assert_held(&j->lock);
 185
 186         rcu_read_lock();
 187         for_each_member_device_rcu(ca, c, i,
 188                                    &c->rw_devs[BCH_DATA_journal]) {
 189                 struct journal_device *ja = &ca->journal;
 190
 191                 if (!ja->nr)
 192                         continue;
 193
 194                 while (ja->dirty_idx != ja->cur_idx &&
 195                        ja->bucket_seq[ja->dirty_idx] < journal_last_seq(j))
 196                         ja->dirty_idx = (ja->dirty_idx + 1) % ja->nr;
 197
 198                 while (ja->dirty_idx_ondisk != ja->dirty_idx &&
 199                        ja->bucket_seq[ja->dirty_idx_ondisk] < j->last_seq_ondisk)
 200                         ja->dirty_idx_ondisk = (ja->dirty_idx_ondisk + 1) % ja->nr;
 201
 202                 if (ja->discard_idx != ja->dirty_idx_ondisk)
 203                         can_discard = true;
 204
 205                 max_entry_size = min_t(unsigned, max_entry_size, ca->mi.bucket_size);
 206                 nr_online++;
 207         }
 208         rcu_read_unlock();
 209
 210         j->can_discard = can_discard;
 211
 212         if (nr_online < c->opts.metadata_replicas_required) {
 213                 ret = JOURNAL_ERR_insufficient_devices;
 214                 goto out;
 215         }
 216
 217         nr_devs_want = min_t(unsigned, nr_online, c->opts.metadata_replicas);
 218
 219         for (i = 0; i < journal_space_nr; i++)
 220                 j->space[i] = __journal_space_available(j, nr_devs_want, i);
 221
 222         clean_ondisk    = j->space[journal_space_clean_ondisk].total;
 223         clean           = j->space[journal_space_clean].total;
 224         total           = j->space[journal_space_total].total;
 225
 226         if (!j->space[journal_space_discarded].next_entry)
 227                 ret = JOURNAL_ERR_journal_full;
 228
 229         if ((j->space[journal_space_clean_ondisk].next_entry <
 230              j->space[journal_space_clean_ondisk].total) &&
 231             (clean - clean_ondisk <= total / 8) &&
 232             (clean_ondisk * 2 > clean))
 233                 set_bit(JOURNAL_MAY_SKIP_FLUSH, &j->flags);
 234         else
 235                 clear_bit(JOURNAL_MAY_SKIP_FLUSH, &j->flags);
 236
 237         bch2_journal_set_watermark(j);
 238 out:
 239         j->cur_entry_sectors    = !ret ? j->space[journal_space_discarded].next_entry : 0;
 240         j->cur_entry_error      = ret;
 241
 242         if (!ret)
 243                 journal_wake(j);
 244 }
 245
 246 /* Discards - last part of journal reclaim: */
 247
 248 static bool should_discard_bucket(struct journal *j, struct journal_device *ja)
 249 {
 250         bool ret;
 251
 252         spin_lock(&j->lock);
 253         ret = ja->discard_idx != ja->dirty_idx_ondisk;
 254         spin_unlock(&j->lock);
 255
 256         return ret;
 257 }
 258
 259 /*
 260  * Advance ja->discard_idx as long as it points to buckets that are no longer
 261  * dirty, issuing discards if necessary:
 262  */
 263 void bch2_journal_do_discards(struct journal *j)
 264 {
 265         struct bch_fs *c = container_of(j, struct bch_fs, journal);
 266         struct bch_dev *ca;
 267         unsigned iter;
 268
 269         mutex_lock(&j->discard_lock);
 270
 271         for_each_rw_member(ca, c, iter) {
 272                 struct journal_device *ja = &ca->journal;
 273
 274                 while (should_discard_bucket(j, ja)) {
 275                         if (!c->opts.nochanges &&
 276                             ca->mi.discard &&
 277                             bdev_max_discard_sectors(ca->disk_sb.bdev))
 278                                 blkdev_issue_discard(ca->disk_sb.bdev,
 279                                         bucket_to_sector(ca,
 280                                                 ja->buckets[ja->discard_idx]),
 281                                         ca->mi.bucket_size, GFP_NOFS);
 282
 283                         spin_lock(&j->lock);
 284                         ja->discard_idx = (ja->discard_idx + 1) % ja->nr;
 285
 286                         bch2_journal_space_available(j);
 287                         spin_unlock(&j->lock);
 288                 }
 289         }
 290
 291         mutex_unlock(&j->discard_lock);
 292 }
 293
 294 /*
 295  * Journal entry pinning - machinery for holding a reference on a given journal
 296  * entry, holding it open to ensure it gets replayed during recovery:
 297  */
 298
 299 void bch2_journal_reclaim_fast(struct journal *j)
 300 {
 301         bool popped = false;
 302
 303         lockdep_assert_held(&j->lock);
 304
 305         /*
 306          * Unpin journal entries whose reference counts reached zero, meaning
 307          * all btree nodes got written out
 308          */
 309         while (!fifo_empty(&j->pin) &&
 310                j->pin.front <= j->seq_ondisk &&
 311                !atomic_read(&fifo_peek_front(&j->pin).count)) {
 312                 j->pin.front++;
 313                 popped = true;
 314         }
 315
 316         if (popped)
 317                 bch2_journal_space_available(j);
 318 }
 319
 320 bool __bch2_journal_pin_put(struct journal *j, u64 seq)
 321 {
 322         struct journal_entry_pin_list *pin_list = journal_seq_pin(j, seq);
 323
 324         return atomic_dec_and_test(&pin_list->count);
 325 }
 326
 327 void bch2_journal_pin_put(struct journal *j, u64 seq)
 328 {
 329         if (__bch2_journal_pin_put(j, seq)) {
 330                 spin_lock(&j->lock);
 331                 bch2_journal_reclaim_fast(j);
 332                 spin_unlock(&j->lock);
 333         }
 334 }
 335
 336 static inline bool __journal_pin_drop(struct journal *j,
 337                                       struct journal_entry_pin *pin)
 338 {
 339         struct journal_entry_pin_list *pin_list;
 340
 341         if (!journal_pin_active(pin))
 342                 return false;
 343
 344         if (j->flush_in_progress == pin)
 345                 j->flush_in_progress_dropped = true;
 346
 347         pin_list = journal_seq_pin(j, pin->seq);
 348         pin->seq = 0;
 349         list_del_init(&pin->list);
 350
 351         /*
 352          * Unpinning a journal entry may make journal_next_bucket() succeed, if
 353          * writing a new last_seq will now make another bucket available:
 354          */
 355         return atomic_dec_and_test(&pin_list->count) &&
 356                 pin_list == &fifo_peek_front(&j->pin);
 357 }
 358
 359 void bch2_journal_pin_drop(struct journal *j,
 360                            struct journal_entry_pin *pin)
 361 {
 362         spin_lock(&j->lock);
 363         if (__journal_pin_drop(j, pin))
 364                 bch2_journal_reclaim_fast(j);
 365         spin_unlock(&j->lock);
 366 }
 367
 368 static enum journal_pin_type journal_pin_type(journal_pin_flush_fn fn)
 369 {
 370         if (fn == bch2_btree_node_flush0 ||
 371             fn == bch2_btree_node_flush1)
 372                 return JOURNAL_PIN_btree;
 373         else if (fn == bch2_btree_key_cache_journal_flush)
 374                 return JOURNAL_PIN_key_cache;
 375         else
 376                 return JOURNAL_PIN_other;
 377 }
 378
 379 static inline void bch2_journal_pin_set_locked(struct journal *j, u64 seq,
 380                           struct journal_entry_pin *pin,
 381                           journal_pin_flush_fn flush_fn,
 382                           enum journal_pin_type type)
 383 {
 384         struct journal_entry_pin_list *pin_list = journal_seq_pin(j, seq);
 385
 386         /*
 387          * flush_fn is how we identify journal pins in debugfs, so must always
 388          * exist, even if it doesn't do anything:
 389          */
 390         BUG_ON(!flush_fn);
 391
 392         atomic_inc(&pin_list->count);
 393         pin->seq        = seq;
 394         pin->flush      = flush_fn;
 395         list_add(&pin->list, &pin_list->list[type]);
 396 }
 397
 398 void bch2_journal_pin_copy(struct journal *j,
 399                            struct journal_entry_pin *dst,
 400                            struct journal_entry_pin *src,
 401                            journal_pin_flush_fn flush_fn)
 402 {
 403         bool reclaim;
 404
 405         spin_lock(&j->lock);
 406
 407         u64 seq = READ_ONCE(src->seq);
 408
 409         if (seq < journal_last_seq(j)) {
 410                 /*
 411                  * bch2_journal_pin_copy() raced with bch2_journal_pin_drop() on
 412                  * the src pin - with the pin dropped, the entry to pin might no
 413                  * longer to exist, but that means there's no longer anything to
 414                  * copy and we can bail out here:
 415                  */
 416                 spin_unlock(&j->lock);
 417                 return;
 418         }
 419
 420         reclaim = __journal_pin_drop(j, dst);
 421
 422         bch2_journal_pin_set_locked(j, seq, dst, flush_fn, journal_pin_type(flush_fn));
 423
 424         if (reclaim)
 425                 bch2_journal_reclaim_fast(j);
 426         spin_unlock(&j->lock);
 427
 428         /*
 429          * If the journal is currently full,  we might want to call flush_fn
 430          * immediately:
 431          */
 432         journal_wake(j);
 433 }
 434
 435 void bch2_journal_pin_set(struct journal *j, u64 seq,
 436                           struct journal_entry_pin *pin,
 437                           journal_pin_flush_fn flush_fn)
 438 {
 439         bool reclaim;
 440
 441         spin_lock(&j->lock);
 442
 443         BUG_ON(seq < journal_last_seq(j));
 444
 445         reclaim = __journal_pin_drop(j, pin);
 446
 447         bch2_journal_pin_set_locked(j, seq, pin, flush_fn, journal_pin_type(flush_fn));
 448
 449         if (reclaim)
 450                 bch2_journal_reclaim_fast(j);
 451         spin_unlock(&j->lock);
 452
 453         /*
 454          * If the journal is currently full,  we might want to call flush_fn
 455          * immediately:
 456          */
 457         journal_wake(j);
 458 }
 459
 460 /**
 461  * bch2_journal_pin_flush: ensure journal pin callback is no longer running
 462  * @j:          journal object
 463  * @pin:        pin to flush
 464  */
 465 void bch2_journal_pin_flush(struct journal *j, struct journal_entry_pin *pin)
 466 {
 467         BUG_ON(journal_pin_active(pin));
 468
 469         wait_event(j->pin_flush_wait, j->flush_in_progress != pin);
 470 }
 471
 472 /*
 473  * Journal reclaim: flush references to open journal entries to reclaim space in
 474  * the journal
 475  *
 476  * May be done by the journal code in the background as needed to free up space
 477  * for more journal entries, or as part of doing a clean shutdown, or to migrate
 478  * data off of a specific device:
 479  */
 480
 481 static struct journal_entry_pin *
 482 journal_get_next_pin(struct journal *j,
 483                      u64 seq_to_flush,
 484                      unsigned allowed_below_seq,
 485                      unsigned allowed_above_seq,
 486                      u64 *seq)
 487 {
 488         struct journal_entry_pin_list *pin_list;
 489         struct journal_entry_pin *ret = NULL;
 490         unsigned i;
 491
 492         fifo_for_each_entry_ptr(pin_list, &j->pin, *seq) {
 493                 if (*seq > seq_to_flush && !allowed_above_seq)
 494                         break;
 495
 496                 for (i = 0; i < JOURNAL_PIN_NR; i++)
 497                         if ((((1U << i) & allowed_below_seq) && *seq <= seq_to_flush) ||
 498                             ((1U << i) & allowed_above_seq)) {
 499                                 ret = list_first_entry_or_null(&pin_list->list[i],
 500                                         struct journal_entry_pin, list);
 501                                 if (ret)
 502                                         return ret;
 503                         }
 504         }
 505
 506         return NULL;
 507 }
 508
 509 /* returns true if we did work */
 510 static size_t journal_flush_pins(struct journal *j,
 511                                  u64 seq_to_flush,
 512                                  unsigned allowed_below_seq,
 513                                  unsigned allowed_above_seq,
 514                                  unsigned min_any,
 515                                  unsigned min_key_cache)
 516 {
 517         struct journal_entry_pin *pin;
 518         size_t nr_flushed = 0;
 519         journal_pin_flush_fn flush_fn;
 520         u64 seq;
 521         int err;
 522
 523         lockdep_assert_held(&j->reclaim_lock);
 524
 525         while (1) {
 526                 unsigned allowed_above = allowed_above_seq;
 527                 unsigned allowed_below = allowed_below_seq;
 528
 529                 if (min_any) {
 530                         allowed_above |= ~0;
 531                         allowed_below |= ~0;
 532                 }
 533
 534                 if (min_key_cache) {
 535                         allowed_above |= 1U << JOURNAL_PIN_key_cache;
 536                         allowed_below |= 1U << JOURNAL_PIN_key_cache;
 537                 }
 538
 539                 cond_resched();
 540
 541                 j->last_flushed = jiffies;
 542
 543                 spin_lock(&j->lock);
 544                 pin = journal_get_next_pin(j, seq_to_flush, allowed_below, allowed_above, &seq);
 545                 if (pin) {
 546                         BUG_ON(j->flush_in_progress);
 547                         j->flush_in_progress = pin;
 548                         j->flush_in_progress_dropped = false;
 549                         flush_fn = pin->flush;
 550                 }
 551                 spin_unlock(&j->lock);
 552
 553                 if (!pin)
 554                         break;
 555
 556                 if (min_key_cache && pin->flush == bch2_btree_key_cache_journal_flush)
 557                         min_key_cache--;
 558
 559                 if (min_any)
 560                         min_any--;
 561
 562                 err = flush_fn(j, pin, seq);
 563
 564                 spin_lock(&j->lock);
 565                 /* Pin might have been dropped or rearmed: */
 566                 if (likely(!err && !j->flush_in_progress_dropped))
 567                         list_move(&pin->list, &journal_seq_pin(j, seq)->flushed);
 568                 j->flush_in_progress = NULL;
 569                 j->flush_in_progress_dropped = false;
 570                 spin_unlock(&j->lock);
 571
 572                 wake_up(&j->pin_flush_wait);
 573
 574                 if (err)
 575                         break;
 576
 577                 nr_flushed++;
 578         }
 579
 580         return nr_flushed;
 581 }
 582
 583 static u64 journal_seq_to_flush(struct journal *j)
 584 {
 585         struct bch_fs *c = container_of(j, struct bch_fs, journal);
 586         struct bch_dev *ca;
 587         u64 seq_to_flush = 0;
 588         unsigned iter;
 589
 590         spin_lock(&j->lock);
 591
 592         for_each_rw_member(ca, c, iter) {
 593                 struct journal_device *ja = &ca->journal;
 594                 unsigned nr_buckets, bucket_to_flush;
 595
 596                 if (!ja->nr)
 597                         continue;
 598
 599                 /* Try to keep the journal at most half full: */
 600                 nr_buckets = ja->nr / 2;
 601
 602                 nr_buckets = min(nr_buckets, ja->nr);
 603
 604                 bucket_to_flush = (ja->cur_idx + nr_buckets) % ja->nr;
 605                 seq_to_flush = max(seq_to_flush,
 606                                    ja->bucket_seq[bucket_to_flush]);
 607         }
 608
 609         /* Also flush if the pin fifo is more than half full */
 610         seq_to_flush = max_t(s64, seq_to_flush,
 611                              (s64) journal_cur_seq(j) -
 612                              (j->pin.size >> 1));
 613         spin_unlock(&j->lock);
 614
 615         return seq_to_flush;
 616 }
 617
 618 /**
 619  * __bch2_journal_reclaim - free up journal buckets
 620  * @j:          journal object
 621  * @direct:     direct or background reclaim?
 622  * @kicked:     requested to run since we last ran?
 623  * Returns:     0 on success, or -EIO if the journal has been shutdown
 624  *
 625  * Background journal reclaim writes out btree nodes. It should be run
 626  * early enough so that we never completely run out of journal buckets.
 627  *
 628  * High watermarks for triggering background reclaim:
 629  * - FIFO has fewer than 512 entries left
 630  * - fewer than 25% journal buckets free
 631  *
 632  * Background reclaim runs until low watermarks are reached:
 633  * - FIFO has more than 1024 entries left
 634  * - more than 50% journal buckets free
 635  *
 636  * As long as a reclaim can complete in the time it takes to fill up
 637  * 512 journal entries or 25% of all journal buckets, then
 638  * journal_next_bucket() should not stall.
 639  */
 640 static int __bch2_journal_reclaim(struct journal *j, bool direct, bool kicked)
 641 {
 642         struct bch_fs *c = container_of(j, struct bch_fs, journal);
 643         bool kthread = (current->flags & PF_KTHREAD) != 0;
 644         u64 seq_to_flush;
 645         size_t min_nr, min_key_cache, nr_flushed;
 646         unsigned flags;
 647         int ret = 0;
 648
 649         /*
 650          * We can't invoke memory reclaim while holding the reclaim_lock -
 651          * journal reclaim is required to make progress for memory reclaim
 652          * (cleaning the caches), so we can't get stuck in memory reclaim while
 653          * we're holding the reclaim lock:
 654          */
 655         lockdep_assert_held(&j->reclaim_lock);
 656         flags = memalloc_noreclaim_save();
 657
 658         do {
 659                 if (kthread && kthread_should_stop())
 660                         break;
 661
 662                 if (bch2_journal_error(j)) {
 663                         ret = -EIO;
 664                         break;
 665                 }
 666
 667                 bch2_journal_do_discards(j);
 668
 669                 seq_to_flush = journal_seq_to_flush(j);
 670                 min_nr = 0;
 671
 672                 /*
 673                  * If it's been longer than j->reclaim_delay_ms since we last flushed,
 674                  * make sure to flush at least one journal pin:
 675                  */
 676                 if (time_after(jiffies, j->last_flushed +
 677                                msecs_to_jiffies(c->opts.journal_reclaim_delay)))
 678                         min_nr = 1;
 679
 680                 if (j->watermark != BCH_WATERMARK_stripe)
 681                         min_nr = 1;
 682
 683                 if (atomic_read(&c->btree_cache.dirty) * 2 > c->btree_cache.used)
 684                         min_nr = 1;
 685
 686                 min_key_cache = min(bch2_nr_btree_keys_need_flush(c), (size_t) 128);
 687
 688                 trace_and_count(c, journal_reclaim_start, c,
 689                                 direct, kicked,
 690                                 min_nr, min_key_cache,
 691                                 atomic_read(&c->btree_cache.dirty),
 692                                 c->btree_cache.used,
 693                                 atomic_long_read(&c->btree_key_cache.nr_dirty),
 694                                 atomic_long_read(&c->btree_key_cache.nr_keys));
 695
 696                 nr_flushed = journal_flush_pins(j, seq_to_flush,
 697                                                 ~0, 0,
 698                                                 min_nr, min_key_cache);
 699
 700                 if (direct)
 701                         j->nr_direct_reclaim += nr_flushed;
 702                 else
 703                         j->nr_background_reclaim += nr_flushed;
 704                 trace_and_count(c, journal_reclaim_finish, c, nr_flushed);
 705
 706                 if (nr_flushed)
 707                         wake_up(&j->reclaim_wait);
 708         } while ((min_nr || min_key_cache) && nr_flushed && !direct);
 709
 710         memalloc_noreclaim_restore(flags);
 711
 712         return ret;
 713 }
 714
 715 int bch2_journal_reclaim(struct journal *j)
 716 {
 717         return __bch2_journal_reclaim(j, true, true);
 718 }
 719
 720 static int bch2_journal_reclaim_thread(void *arg)
 721 {
 722         struct journal *j = arg;
 723         struct bch_fs *c = container_of(j, struct bch_fs, journal);
 724         unsigned long delay, now;
 725         bool journal_empty;
 726         int ret = 0;
 727
 728         set_freezable();
 729
 730         j->last_flushed = jiffies;
 731
 732         while (!ret && !kthread_should_stop()) {
 733                 bool kicked = j->reclaim_kicked;
 734
 735                 j->reclaim_kicked = false;
 736
 737                 mutex_lock(&j->reclaim_lock);
 738                 ret = __bch2_journal_reclaim(j, false, kicked);
 739                 mutex_unlock(&j->reclaim_lock);
 740
 741                 now = jiffies;
 742                 delay = msecs_to_jiffies(c->opts.journal_reclaim_delay);
 743                 j->next_reclaim = j->last_flushed + delay;
 744
 745                 if (!time_in_range(j->next_reclaim, now, now + delay))
 746                         j->next_reclaim = now + delay;
 747
 748                 while (1) {
 749                         set_current_state(TASK_INTERRUPTIBLE|TASK_FREEZABLE);
 750                         if (kthread_should_stop())
 751                                 break;
 752                         if (j->reclaim_kicked)
 753                                 break;
 754
 755                         spin_lock(&j->lock);
 756                         journal_empty = fifo_empty(&j->pin);
 757                         spin_unlock(&j->lock);
 758
 759                         if (journal_empty)
 760                                 schedule();
 761                         else if (time_after(j->next_reclaim, jiffies))
 762                                 schedule_timeout(j->next_reclaim - jiffies);
 763                         else
 764                                 break;
 765                 }
 766                 __set_current_state(TASK_RUNNING);
 767         }
 768
 769         return 0;
 770 }
 771
 772 void bch2_journal_reclaim_stop(struct journal *j)
 773 {
 774         struct task_struct *p = j->reclaim_thread;
 775
 776         j->reclaim_thread = NULL;
 777
 778         if (p) {
 779                 kthread_stop(p);
 780                 put_task_struct(p);
 781         }
 782 }
 783
 784 int bch2_journal_reclaim_start(struct journal *j)
 785 {
 786         struct bch_fs *c = container_of(j, struct bch_fs, journal);
 787         struct task_struct *p;
 788         int ret;
 789
 790         if (j->reclaim_thread)
 791                 return 0;
 792
 793         p = kthread_create(bch2_journal_reclaim_thread, j,
 794                            "bch-reclaim/%s", c->name);
 795         ret = PTR_ERR_OR_ZERO(p);
 796         if (ret) {
 797                 bch_err_msg(c, ret, "creating journal reclaim thread");
 798                 return ret;
 799         }
 800
 801         get_task_struct(p);
 802         j->reclaim_thread = p;
 803         wake_up_process(p);
 804         return 0;
 805 }
 806
 807 static int journal_flush_done(struct journal *j, u64 seq_to_flush,
 808                               bool *did_work)
 809 {
 810         int ret;
 811
 812         ret = bch2_journal_error(j);
 813         if (ret)
 814                 return ret;
 815
 816         mutex_lock(&j->reclaim_lock);
 817
 818         if (journal_flush_pins(j, seq_to_flush,
 819                                (1U << JOURNAL_PIN_key_cache)|
 820                                (1U << JOURNAL_PIN_other), 0, 0, 0) ||
 821             journal_flush_pins(j, seq_to_flush,
 822                                (1U << JOURNAL_PIN_btree), 0, 0, 0))
 823                 *did_work = true;
 824
 825         if (seq_to_flush > journal_cur_seq(j))
 826                 bch2_journal_entry_close(j);
 827
 828         spin_lock(&j->lock);
 829         /*
 830          * If journal replay hasn't completed, the unreplayed journal entries
 831          * hold refs on their corresponding sequence numbers
 832          */
 833         ret = !test_bit(JOURNAL_REPLAY_DONE, &j->flags) ||
 834                 journal_last_seq(j) > seq_to_flush ||
 835                 !fifo_used(&j->pin);
 836
 837         spin_unlock(&j->lock);
 838         mutex_unlock(&j->reclaim_lock);
 839
 840         return ret;
 841 }
 842
 843 bool bch2_journal_flush_pins(struct journal *j, u64 seq_to_flush)
 844 {
 845         /* time_stats this */
 846         bool did_work = false;
 847
 848         if (!test_bit(JOURNAL_STARTED, &j->flags))
 849                 return false;
 850
 851         closure_wait_event(&j->async_wait,
 852                 journal_flush_done(j, seq_to_flush, &did_work));
 853
 854         return did_work;
 855 }
 856
 857 int bch2_journal_flush_device_pins(struct journal *j, int dev_idx)
 858 {
 859         struct bch_fs *c = container_of(j, struct bch_fs, journal);
 860         struct journal_entry_pin_list *p;
 861         u64 iter, seq = 0;
 862         int ret = 0;
 863
 864         spin_lock(&j->lock);
 865         fifo_for_each_entry_ptr(p, &j->pin, iter)
 866                 if (dev_idx >= 0
 867                     ? bch2_dev_list_has_dev(p->devs, dev_idx)
 868                     : p->devs.nr < c->opts.metadata_replicas)
 869                         seq = iter;
 870         spin_unlock(&j->lock);
 871
 872         bch2_journal_flush_pins(j, seq);
 873
 874         ret = bch2_journal_error(j);
 875         if (ret)
 876                 return ret;
 877
 878         mutex_lock(&c->replicas_gc_lock);
 879         bch2_replicas_gc_start(c, 1 << BCH_DATA_journal);
 880
 881         /*
 882          * Now that we've populated replicas_gc, write to the journal to mark
 883          * active journal devices. This handles the case where the journal might
 884          * be empty. Otherwise we could clear all journal replicas and
 885          * temporarily put the fs into an unrecoverable state. Journal recovery
 886          * expects to find devices marked for journal data on unclean mount.
 887          */
 888         ret = bch2_journal_meta(&c->journal);
 889         if (ret)
 890                 goto err;
 891
 892         seq = 0;
 893         spin_lock(&j->lock);
 894         while (!ret) {
 895                 struct bch_replicas_padded replicas;
 896
 897                 seq = max(seq, journal_last_seq(j));
 898                 if (seq >= j->pin.back)
 899                         break;
 900                 bch2_devlist_to_replicas(&replicas.e, BCH_DATA_journal,
 901                                          journal_seq_pin(j, seq)->devs);
 902                 seq++;
 903
 904                 spin_unlock(&j->lock);
 905                 ret = bch2_mark_replicas(c, &replicas.e);
 906                 spin_lock(&j->lock);
 907         }
 908         spin_unlock(&j->lock);
 909 err:
 910         ret = bch2_replicas_gc_end(c, ret);
 911         mutex_unlock(&c->replicas_gc_lock);
 912
 913         return ret;
 914 }