drivers/md/bcache/request.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Main bcache entry point - handle a read or a write request and decide what to
   4  * do with it; the make_request functions are called by the block layer.
   5  *
   6  * Copyright 2010, 2011 Kent Overstreet <[email protected]>
   7  * Copyright 2012 Google, Inc.
   8  */
   9
  10 #include "bcache.h"
  11 #include "btree.h"
  12 #include "debug.h"
  13 #include "request.h"
  14 #include "writeback.h"
  15
  16 #include <linux/module.h>
  17 #include <linux/hash.h>
  18 #include <linux/random.h>
  19 #include <linux/backing-dev.h>
  20
  21 #include <trace/events/bcache.h>
  22
  23 #define CUTOFF_CACHE_ADD        95
  24 #define CUTOFF_CACHE_READA      90
  25
  26 struct kmem_cache *bch_search_cache;
  27
  28 static CLOSURE_CALLBACK(bch_data_insert_start);
  29
  30 static unsigned int cache_mode(struct cached_dev *dc)
  31 {
  32         return BDEV_CACHE_MODE(&dc->sb);
  33 }
  34
  35 static bool verify(struct cached_dev *dc)
  36 {
  37         return dc->verify;
  38 }
  39
  40 static void bio_csum(struct bio *bio, struct bkey *k)
  41 {
  42         struct bio_vec bv;
  43         struct bvec_iter iter;
  44         uint64_t csum = 0;
  45
  46         bio_for_each_segment(bv, bio, iter) {
  47                 void *d = bvec_kmap_local(&bv);
  48
  49                 csum = crc64_be(csum, d, bv.bv_len);
  50                 kunmap_local(d);
  51         }
  52
  53         k->ptr[KEY_PTRS(k)] = csum & (~0ULL >> 1);
  54 }
  55
  56 /* Insert data into cache */
  57
  58 static CLOSURE_CALLBACK(bch_data_insert_keys)
  59 {
  60         closure_type(op, struct data_insert_op, cl);
  61         atomic_t *journal_ref = NULL;
  62         struct bkey *replace_key = op->replace ? &op->replace_key : NULL;
  63         int ret;
  64
  65         if (!op->replace)
  66                 journal_ref = bch_journal(op->c, &op->insert_keys,
  67                                           op->flush_journal ? cl : NULL);
  68
  69         ret = bch_btree_insert(op->c, &op->insert_keys,
  70                                journal_ref, replace_key);
  71         if (ret == -ESRCH) {
  72                 op->replace_collision = true;
  73         } else if (ret) {
  74                 op->status              = BLK_STS_RESOURCE;
  75                 op->insert_data_done    = true;
  76         }
  77
  78         if (journal_ref)
  79                 atomic_dec_bug(journal_ref);
  80
  81         if (!op->insert_data_done) {
  82                 continue_at(cl, bch_data_insert_start, op->wq);
  83                 return;
  84         }
  85
  86         bch_keylist_free(&op->insert_keys);
  87         closure_return(cl);
  88 }
  89
  90 static int bch_keylist_realloc(struct keylist *l, unsigned int u64s,
  91                                struct cache_set *c)
  92 {
  93         size_t oldsize = bch_keylist_nkeys(l);
  94         size_t newsize = oldsize + u64s;
  95
  96         /*
  97          * The journalling code doesn't handle the case where the keys to insert
  98          * is bigger than an empty write: If we just return -ENOMEM here,
  99          * bch_data_insert_keys() will insert the keys created so far
 100          * and finish the rest when the keylist is empty.
 101          */
 102         if (newsize * sizeof(uint64_t) > block_bytes(c->cache) - sizeof(struct jset))
 103                 return -ENOMEM;
 104
 105         return __bch_keylist_realloc(l, u64s);
 106 }
 107
 108 static void bch_data_invalidate(struct closure *cl)
 109 {
 110         struct data_insert_op *op = container_of(cl, struct data_insert_op, cl);
 111         struct bio *bio = op->bio;
 112
 113         pr_debug("invalidating %i sectors from %llu\n",
 114                  bio_sectors(bio), (uint64_t) bio->bi_iter.bi_sector);
 115
 116         while (bio_sectors(bio)) {
 117                 unsigned int sectors = min(bio_sectors(bio),
 118                                        1U << (KEY_SIZE_BITS - 1));
 119
 120                 if (bch_keylist_realloc(&op->insert_keys, 2, op->c))
 121                         goto out;
 122
 123                 bio->bi_iter.bi_sector  += sectors;
 124                 bio->bi_iter.bi_size    -= sectors << 9;
 125
 126                 bch_keylist_add(&op->insert_keys,
 127                                 &KEY(op->inode,
 128                                      bio->bi_iter.bi_sector,
 129                                      sectors));
 130         }
 131
 132         op->insert_data_done = true;
 133         /* get in bch_data_insert() */
 134         bio_put(bio);
 135 out:
 136         continue_at(cl, bch_data_insert_keys, op->wq);
 137 }
 138
 139 static CLOSURE_CALLBACK(bch_data_insert_error)
 140 {
 141         closure_type(op, struct data_insert_op, cl);
 142
 143         /*
 144          * Our data write just errored, which means we've got a bunch of keys to
 145          * insert that point to data that wasn't successfully written.
 146          *
 147          * We don't have to insert those keys but we still have to invalidate
 148          * that region of the cache - so, if we just strip off all the pointers
 149          * from the keys we'll accomplish just that.
 150          */
 151
 152         struct bkey *src = op->insert_keys.keys, *dst = op->insert_keys.keys;
 153
 154         while (src != op->insert_keys.top) {
 155                 struct bkey *n = bkey_next(src);
 156
 157                 SET_KEY_PTRS(src, 0);
 158                 memmove(dst, src, bkey_bytes(src));
 159
 160                 dst = bkey_next(dst);
 161                 src = n;
 162         }
 163
 164         op->insert_keys.top = dst;
 165
 166         bch_data_insert_keys(&cl->work);
 167 }
 168
 169 static void bch_data_insert_endio(struct bio *bio)
 170 {
 171         struct closure *cl = bio->bi_private;
 172         struct data_insert_op *op = container_of(cl, struct data_insert_op, cl);
 173
 174         if (bio->bi_status) {
 175                 /* TODO: We could try to recover from this. */
 176                 if (op->writeback)
 177                         op->status = bio->bi_status;
 178                 else if (!op->replace)
 179                         set_closure_fn(cl, bch_data_insert_error, op->wq);
 180                 else
 181                         set_closure_fn(cl, NULL, NULL);
 182         }
 183
 184         bch_bbio_endio(op->c, bio, bio->bi_status, "writing data to cache");
 185 }
 186
 187 static CLOSURE_CALLBACK(bch_data_insert_start)
 188 {
 189         closure_type(op, struct data_insert_op, cl);
 190         struct bio *bio = op->bio, *n;
 191
 192         if (op->bypass)
 193                 return bch_data_invalidate(cl);
 194
 195         if (atomic_sub_return(bio_sectors(bio), &op->c->sectors_to_gc) < 0)
 196                 wake_up_gc(op->c);
 197
 198         /*
 199          * Journal writes are marked REQ_PREFLUSH; if the original write was a
 200          * flush, it'll wait on the journal write.
 201          */
 202         bio->bi_opf &= ~(REQ_PREFLUSH|REQ_FUA);
 203
 204         do {
 205                 unsigned int i;
 206                 struct bkey *k;
 207                 struct bio_set *split = &op->c->bio_split;
 208
 209                 /* 1 for the device pointer and 1 for the chksum */
 210                 if (bch_keylist_realloc(&op->insert_keys,
 211                                         3 + (op->csum ? 1 : 0),
 212                                         op->c)) {
 213                         continue_at(cl, bch_data_insert_keys, op->wq);
 214                         return;
 215                 }
 216
 217                 k = op->insert_keys.top;
 218                 bkey_init(k);
 219                 SET_KEY_INODE(k, op->inode);
 220                 SET_KEY_OFFSET(k, bio->bi_iter.bi_sector);
 221
 222                 if (!bch_alloc_sectors(op->c, k, bio_sectors(bio),
 223                                        op->write_point, op->write_prio,
 224                                        op->writeback))
 225                         goto err;
 226
 227                 n = bio_next_split(bio, KEY_SIZE(k), GFP_NOIO, split);
 228
 229                 n->bi_end_io    = bch_data_insert_endio;
 230                 n->bi_private   = cl;
 231
 232                 if (op->writeback) {
 233                         SET_KEY_DIRTY(k, true);
 234
 235                         for (i = 0; i < KEY_PTRS(k); i++)
 236                                 SET_GC_MARK(PTR_BUCKET(op->c, k, i),
 237                                             GC_MARK_DIRTY);
 238                 }
 239
 240                 SET_KEY_CSUM(k, op->csum);
 241                 if (KEY_CSUM(k))
 242                         bio_csum(n, k);
 243
 244                 trace_bcache_cache_insert(k);
 245                 bch_keylist_push(&op->insert_keys);
 246
 247                 n->bi_opf = REQ_OP_WRITE;
 248                 bch_submit_bbio(n, op->c, k, 0);
 249         } while (n != bio);
 250
 251         op->insert_data_done = true;
 252         continue_at(cl, bch_data_insert_keys, op->wq);
 253         return;
 254 err:
 255         /* bch_alloc_sectors() blocks if s->writeback = true */
 256         BUG_ON(op->writeback);
 257
 258         /*
 259          * But if it's not a writeback write we'd rather just bail out if
 260          * there aren't any buckets ready to write to - it might take awhile and
 261          * we might be starving btree writes for gc or something.
 262          */
 263
 264         if (!op->replace) {
 265                 /*
 266                  * Writethrough write: We can't complete the write until we've
 267                  * updated the index. But we don't want to delay the write while
 268                  * we wait for buckets to be freed up, so just invalidate the
 269                  * rest of the write.
 270                  */
 271                 op->bypass = true;
 272                 return bch_data_invalidate(cl);
 273         } else {
 274                 /*
 275                  * From a cache miss, we can just insert the keys for the data
 276                  * we have written or bail out if we didn't do anything.
 277                  */
 278                 op->insert_data_done = true;
 279                 bio_put(bio);
 280
 281                 if (!bch_keylist_empty(&op->insert_keys))
 282                         continue_at(cl, bch_data_insert_keys, op->wq);
 283                 else
 284                         closure_return(cl);
 285         }
 286 }
 287
 288 /**
 289  * bch_data_insert - stick some data in the cache
 290  * @cl: closure pointer.
 291  *
 292  * This is the starting point for any data to end up in a cache device; it could
 293  * be from a normal write, or a writeback write, or a write to a flash only
 294  * volume - it's also used by the moving garbage collector to compact data in
 295  * mostly empty buckets.
 296  *
 297  * It first writes the data to the cache, creating a list of keys to be inserted
 298  * (if the data had to be fragmented there will be multiple keys); after the
 299  * data is written it calls bch_journal, and after the keys have been added to
 300  * the next journal write they're inserted into the btree.
 301  *
 302  * It inserts the data in op->bio; bi_sector is used for the key offset,
 303  * and op->inode is used for the key inode.
 304  *
 305  * If op->bypass is true, instead of inserting the data it invalidates the
 306  * region of the cache represented by op->bio and op->inode.
 307  */
 308 CLOSURE_CALLBACK(bch_data_insert)
 309 {
 310         closure_type(op, struct data_insert_op, cl);
 311
 312         trace_bcache_write(op->c, op->inode, op->bio,
 313                            op->writeback, op->bypass);
 314
 315         bch_keylist_init(&op->insert_keys);
 316         bio_get(op->bio);
 317         bch_data_insert_start(&cl->work);
 318 }
 319
 320 /*
 321  * Congested?  Return 0 (not congested) or the limit (in sectors)
 322  * beyond which we should bypass the cache due to congestion.
 323  */
 324 unsigned int bch_get_congested(const struct cache_set *c)
 325 {
 326         int i;
 327
 328         if (!c->congested_read_threshold_us &&
 329             !c->congested_write_threshold_us)
 330                 return 0;
 331
 332         i = (local_clock_us() - c->congested_last_us) / 1024;
 333         if (i < 0)
 334                 return 0;
 335
 336         i += atomic_read(&c->congested);
 337         if (i >= 0)
 338                 return 0;
 339
 340         i += CONGESTED_MAX;
 341
 342         if (i > 0)
 343                 i = fract_exp_two(i, 6);
 344
 345         i -= hweight32(get_random_u32());
 346
 347         return i > 0 ? i : 1;
 348 }
 349
 350 static void add_sequential(struct task_struct *t)
 351 {
 352         ewma_add(t->sequential_io_avg,
 353                  t->sequential_io, 8, 0);
 354
 355         t->sequential_io = 0;
 356 }
 357
 358 static struct hlist_head *iohash(struct cached_dev *dc, uint64_t k)
 359 {
 360         return &dc->io_hash[hash_64(k, RECENT_IO_BITS)];
 361 }
 362
 363 static bool check_should_bypass(struct cached_dev *dc, struct bio *bio)
 364 {
 365         struct cache_set *c = dc->disk.c;
 366         unsigned int mode = cache_mode(dc);
 367         unsigned int sectors, congested;
 368         struct task_struct *task = current;
 369         struct io *i;
 370
 371         if (test_bit(BCACHE_DEV_DETACHING, &dc->disk.flags) ||
 372             (bio_op(bio) == REQ_OP_DISCARD))
 373                 goto skip;
 374
 375         if (c->gc_stats.in_use > CUTOFF_CACHE_ADD) {
 376                 /*
 377                  * If cached buckets are all clean now, 'true' will be
 378                  * returned and all requests will bypass the cache device.
 379                  * Then c->sectors_to_gc has no chance to be negative, and
 380                  * gc thread won't wake up and caching won't work forever.
 381                  * Here call force_wake_up_gc() to avoid such aftermath.
 382                  */
 383                 if (BDEV_STATE(&dc->sb) == BDEV_STATE_CLEAN &&
 384                     c->gc_mark_valid)
 385                         force_wake_up_gc(c);
 386
 387                 goto skip;
 388         }
 389
 390         if (mode == CACHE_MODE_NONE ||
 391             (mode == CACHE_MODE_WRITEAROUND &&
 392              op_is_write(bio_op(bio))))
 393                 goto skip;
 394
 395         /*
 396          * If the bio is for read-ahead or background IO, bypass it or
 397          * not depends on the following situations,
 398          * - If the IO is for meta data, always cache it and no bypass
 399          * - If the IO is not meta data, check dc->cache_reada_policy,
 400          *      BCH_CACHE_READA_ALL: cache it and not bypass
 401          *      BCH_CACHE_READA_META_ONLY: not cache it and bypass
 402          * That is, read-ahead request for metadata always get cached
 403          * (eg, for gfs2 or xfs).
 404          */
 405         if ((bio->bi_opf & (REQ_RAHEAD|REQ_BACKGROUND))) {
 406                 if (!(bio->bi_opf & (REQ_META|REQ_PRIO)) &&
 407                     (dc->cache_readahead_policy != BCH_CACHE_READA_ALL))
 408                         goto skip;
 409         }
 410
 411         if (bio->bi_iter.bi_sector & (c->cache->sb.block_size - 1) ||
 412             bio_sectors(bio) & (c->cache->sb.block_size - 1)) {
 413                 pr_debug("skipping unaligned io\n");
 414                 goto skip;
 415         }
 416
 417         if (bypass_torture_test(dc)) {
 418                 if (get_random_u32_below(4) == 3)
 419                         goto skip;
 420                 else
 421                         goto rescale;
 422         }
 423
 424         congested = bch_get_congested(c);
 425         if (!congested && !dc->sequential_cutoff)
 426                 goto rescale;
 427
 428         spin_lock(&dc->io_lock);
 429
 430         hlist_for_each_entry(i, iohash(dc, bio->bi_iter.bi_sector), hash)
 431                 if (i->last == bio->bi_iter.bi_sector &&
 432                     time_before(jiffies, i->jiffies))
 433                         goto found;
 434
 435         i = list_first_entry(&dc->io_lru, struct io, lru);
 436
 437         add_sequential(task);
 438         i->sequential = 0;
 439 found:
 440         if (i->sequential + bio->bi_iter.bi_size > i->sequential)
 441                 i->sequential   += bio->bi_iter.bi_size;
 442
 443         i->last                  = bio_end_sector(bio);
 444         i->jiffies               = jiffies + msecs_to_jiffies(5000);
 445         task->sequential_io      = i->sequential;
 446
 447         hlist_del(&i->hash);
 448         hlist_add_head(&i->hash, iohash(dc, i->last));
 449         list_move_tail(&i->lru, &dc->io_lru);
 450
 451         spin_unlock(&dc->io_lock);
 452
 453         sectors = max(task->sequential_io,
 454                       task->sequential_io_avg) >> 9;
 455
 456         if (dc->sequential_cutoff &&
 457             sectors >= dc->sequential_cutoff >> 9) {
 458                 trace_bcache_bypass_sequential(bio);
 459                 goto skip;
 460         }
 461
 462         if (congested && sectors >= congested) {
 463                 trace_bcache_bypass_congested(bio);
 464                 goto skip;
 465         }
 466
 467 rescale:
 468         bch_rescale_priorities(c, bio_sectors(bio));
 469         return false;
 470 skip:
 471         bch_mark_sectors_bypassed(c, dc, bio_sectors(bio));
 472         return true;
 473 }
 474
 475 /* Cache lookup */
 476
 477 struct search {
 478         /* Stack frame for bio_complete */
 479         struct closure          cl;
 480
 481         struct bbio             bio;
 482         struct bio              *orig_bio;
 483         struct bio              *cache_miss;
 484         struct bcache_device    *d;
 485
 486         unsigned int            insert_bio_sectors;
 487         unsigned int            recoverable:1;
 488         unsigned int            write:1;
 489         unsigned int            read_dirty_data:1;
 490         unsigned int            cache_missed:1;
 491
 492         struct block_device     *orig_bdev;
 493         unsigned long           start_time;
 494
 495         struct btree_op         op;
 496         struct data_insert_op   iop;
 497 };
 498
 499 static void bch_cache_read_endio(struct bio *bio)
 500 {
 501         struct bbio *b = container_of(bio, struct bbio, bio);
 502         struct closure *cl = bio->bi_private;
 503         struct search *s = container_of(cl, struct search, cl);
 504
 505         /*
 506          * If the bucket was reused while our bio was in flight, we might have
 507          * read the wrong data. Set s->error but not error so it doesn't get
 508          * counted against the cache device, but we'll still reread the data
 509          * from the backing device.
 510          */
 511
 512         if (bio->bi_status)
 513                 s->iop.status = bio->bi_status;
 514         else if (!KEY_DIRTY(&b->key) &&
 515                  ptr_stale(s->iop.c, &b->key, 0)) {
 516                 atomic_long_inc(&s->iop.c->cache_read_races);
 517                 s->iop.status = BLK_STS_IOERR;
 518         }
 519
 520         bch_bbio_endio(s->iop.c, bio, bio->bi_status, "reading from cache");
 521 }
 522
 523 /*
 524  * Read from a single key, handling the initial cache miss if the key starts in
 525  * the middle of the bio
 526  */
 527 static int cache_lookup_fn(struct btree_op *op, struct btree *b, struct bkey *k)
 528 {
 529         struct search *s = container_of(op, struct search, op);
 530         struct bio *n, *bio = &s->bio.bio;
 531         struct bkey *bio_key;
 532         unsigned int ptr;
 533
 534         if (bkey_cmp(k, &KEY(s->iop.inode, bio->bi_iter.bi_sector, 0)) <= 0)
 535                 return MAP_CONTINUE;
 536
 537         if (KEY_INODE(k) != s->iop.inode ||
 538             KEY_START(k) > bio->bi_iter.bi_sector) {
 539                 unsigned int bio_sectors = bio_sectors(bio);
 540                 unsigned int sectors = KEY_INODE(k) == s->iop.inode
 541                         ? min_t(uint64_t, INT_MAX,
 542                                 KEY_START(k) - bio->bi_iter.bi_sector)
 543                         : INT_MAX;
 544                 int ret = s->d->cache_miss(b, s, bio, sectors);
 545
 546                 if (ret != MAP_CONTINUE)
 547                         return ret;
 548
 549                 /* if this was a complete miss we shouldn't get here */
 550                 BUG_ON(bio_sectors <= sectors);
 551         }
 552
 553         if (!KEY_SIZE(k))
 554                 return MAP_CONTINUE;
 555
 556         /* XXX: figure out best pointer - for multiple cache devices */
 557         ptr = 0;
 558
 559         PTR_BUCKET(b->c, k, ptr)->prio = INITIAL_PRIO;
 560
 561         if (KEY_DIRTY(k))
 562                 s->read_dirty_data = true;
 563
 564         n = bio_next_split(bio, min_t(uint64_t, INT_MAX,
 565                                       KEY_OFFSET(k) - bio->bi_iter.bi_sector),
 566                            GFP_NOIO, &s->d->bio_split);
 567
 568         bio_key = &container_of(n, struct bbio, bio)->key;
 569         bch_bkey_copy_single_ptr(bio_key, k, ptr);
 570
 571         bch_cut_front(&KEY(s->iop.inode, n->bi_iter.bi_sector, 0), bio_key);
 572         bch_cut_back(&KEY(s->iop.inode, bio_end_sector(n), 0), bio_key);
 573
 574         n->bi_end_io    = bch_cache_read_endio;
 575         n->bi_private   = &s->cl;
 576
 577         /*
 578          * The bucket we're reading from might be reused while our bio
 579          * is in flight, and we could then end up reading the wrong
 580          * data.
 581          *
 582          * We guard against this by checking (in cache_read_endio()) if
 583          * the pointer is stale again; if so, we treat it as an error
 584          * and reread from the backing device (but we don't pass that
 585          * error up anywhere).
 586          */
 587
 588         __bch_submit_bbio(n, b->c);
 589         return n == bio ? MAP_DONE : MAP_CONTINUE;
 590 }
 591
 592 static CLOSURE_CALLBACK(cache_lookup)
 593 {
 594         closure_type(s, struct search, iop.cl);
 595         struct bio *bio = &s->bio.bio;
 596         struct cached_dev *dc;
 597         int ret;
 598
 599         bch_btree_op_init(&s->op, -1);
 600
 601         ret = bch_btree_map_keys(&s->op, s->iop.c,
 602                                  &KEY(s->iop.inode, bio->bi_iter.bi_sector, 0),
 603                                  cache_lookup_fn, MAP_END_KEY);
 604         if (ret == -EAGAIN) {
 605                 continue_at(cl, cache_lookup, bcache_wq);
 606                 return;
 607         }
 608
 609         /*
 610          * We might meet err when searching the btree, If that happens, we will
 611          * get negative ret, in this scenario we should not recover data from
 612          * backing device (when cache device is dirty) because we don't know
 613          * whether bkeys the read request covered are all clean.
 614          *
 615          * And after that happened, s->iop.status is still its initial value
 616          * before we submit s->bio.bio
 617          */
 618         if (ret < 0) {
 619                 BUG_ON(ret == -EINTR);
 620                 if (s->d && s->d->c &&
 621                                 !UUID_FLASH_ONLY(&s->d->c->uuids[s->d->id])) {
 622                         dc = container_of(s->d, struct cached_dev, disk);
 623                         if (dc && atomic_read(&dc->has_dirty))
 624                                 s->recoverable = false;
 625                 }
 626                 if (!s->iop.status)
 627                         s->iop.status = BLK_STS_IOERR;
 628         }
 629
 630         closure_return(cl);
 631 }
 632
 633 /* Common code for the make_request functions */
 634
 635 static void request_endio(struct bio *bio)
 636 {
 637         struct closure *cl = bio->bi_private;
 638
 639         if (bio->bi_status) {
 640                 struct search *s = container_of(cl, struct search, cl);
 641
 642                 s->iop.status = bio->bi_status;
 643                 /* Only cache read errors are recoverable */
 644                 s->recoverable = false;
 645         }
 646
 647         bio_put(bio);
 648         closure_put(cl);
 649 }
 650
 651 static void backing_request_endio(struct bio *bio)
 652 {
 653         struct closure *cl = bio->bi_private;
 654
 655         if (bio->bi_status) {
 656                 struct search *s = container_of(cl, struct search, cl);
 657                 struct cached_dev *dc = container_of(s->d,
 658                                                      struct cached_dev, disk);
 659                 /*
 660                  * If a bio has REQ_PREFLUSH for writeback mode, it is
 661                  * speically assembled in cached_dev_write() for a non-zero
 662                  * write request which has REQ_PREFLUSH. we don't set
 663                  * s->iop.status by this failure, the status will be decided
 664                  * by result of bch_data_insert() operation.
 665                  */
 666                 if (unlikely(s->iop.writeback &&
 667                              bio->bi_opf & REQ_PREFLUSH)) {
 668                         pr_err("Can't flush %pg: returned bi_status %i\n",
 669                                 dc->bdev, bio->bi_status);
 670                 } else {
 671                         /* set to orig_bio->bi_status in bio_complete() */
 672                         s->iop.status = bio->bi_status;
 673                 }
 674                 s->recoverable = false;
 675                 /* should count I/O error for backing device here */
 676                 bch_count_backing_io_errors(dc, bio);
 677         }
 678
 679         bio_put(bio);
 680         closure_put(cl);
 681 }
 682
 683 static void bio_complete(struct search *s)
 684 {
 685         if (s->orig_bio) {
 686                 /* Count on bcache device */
 687                 bio_end_io_acct_remapped(s->orig_bio, s->start_time,
 688                                          s->orig_bdev);
 689                 trace_bcache_request_end(s->d, s->orig_bio);
 690                 s->orig_bio->bi_status = s->iop.status;
 691                 bio_endio(s->orig_bio);
 692                 s->orig_bio = NULL;
 693         }
 694 }
 695
 696 static void do_bio_hook(struct search *s,
 697                         struct bio *orig_bio,
 698                         bio_end_io_t *end_io_fn)
 699 {
 700         struct bio *bio = &s->bio.bio;
 701
 702         bio_init_clone(orig_bio->bi_bdev, bio, orig_bio, GFP_NOIO);
 703         /*
 704          * bi_end_io can be set separately somewhere else, e.g. the
 705          * variants in,
 706          * - cache_bio->bi_end_io from cached_dev_cache_miss()
 707          * - n->bi_end_io from cache_lookup_fn()
 708          */
 709         bio->bi_end_io          = end_io_fn;
 710         bio->bi_private         = &s->cl;
 711
 712         bio_cnt_set(bio, 3);
 713 }
 714
 715 static CLOSURE_CALLBACK(search_free)
 716 {
 717         closure_type(s, struct search, cl);
 718
 719         atomic_dec(&s->iop.c->search_inflight);
 720
 721         if (s->iop.bio)
 722                 bio_put(s->iop.bio);
 723
 724         bio_complete(s);
 725         closure_debug_destroy(cl);
 726         mempool_free(s, &s->iop.c->search);
 727 }
 728
 729 static inline struct search *search_alloc(struct bio *bio,
 730                 struct bcache_device *d, struct block_device *orig_bdev,
 731                 unsigned long start_time)
 732 {
 733         struct search *s;
 734
 735         s = mempool_alloc(&d->c->search, GFP_NOIO);
 736
 737         closure_init(&s->cl, NULL);
 738         do_bio_hook(s, bio, request_endio);
 739         atomic_inc(&d->c->search_inflight);
 740
 741         s->orig_bio             = bio;
 742         s->cache_miss           = NULL;
 743         s->cache_missed         = 0;
 744         s->d                    = d;
 745         s->recoverable          = 1;
 746         s->write                = op_is_write(bio_op(bio));
 747         s->read_dirty_data      = 0;
 748         /* Count on the bcache device */
 749         s->orig_bdev            = orig_bdev;
 750         s->start_time           = start_time;
 751         s->iop.c                = d->c;
 752         s->iop.bio              = NULL;
 753         s->iop.inode            = d->id;
 754         s->iop.write_point      = hash_long((unsigned long) current, 16);
 755         s->iop.write_prio       = 0;
 756         s->iop.status           = 0;
 757         s->iop.flags            = 0;
 758         s->iop.flush_journal    = op_is_flush(bio->bi_opf);
 759         s->iop.wq               = bcache_wq;
 760
 761         return s;
 762 }
 763
 764 /* Cached devices */
 765
 766 static CLOSURE_CALLBACK(cached_dev_bio_complete)
 767 {
 768         closure_type(s, struct search, cl);
 769         struct cached_dev *dc = container_of(s->d, struct cached_dev, disk);
 770
 771         cached_dev_put(dc);
 772         search_free(&cl->work);
 773 }
 774
 775 /* Process reads */
 776
 777 static CLOSURE_CALLBACK(cached_dev_read_error_done)
 778 {
 779         closure_type(s, struct search, cl);
 780
 781         if (s->iop.replace_collision)
 782                 bch_mark_cache_miss_collision(s->iop.c, s->d);
 783
 784         if (s->iop.bio)
 785                 bio_free_pages(s->iop.bio);
 786
 787         cached_dev_bio_complete(&cl->work);
 788 }
 789
 790 static CLOSURE_CALLBACK(cached_dev_read_error)
 791 {
 792         closure_type(s, struct search, cl);
 793         struct bio *bio = &s->bio.bio;
 794
 795         /*
 796          * If read request hit dirty data (s->read_dirty_data is true),
 797          * then recovery a failed read request from cached device may
 798          * get a stale data back. So read failure recovery is only
 799          * permitted when read request hit clean data in cache device,
 800          * or when cache read race happened.
 801          */
 802         if (s->recoverable && !s->read_dirty_data) {
 803                 /* Retry from the backing device: */
 804                 trace_bcache_read_retry(s->orig_bio);
 805
 806                 s->iop.status = 0;
 807                 do_bio_hook(s, s->orig_bio, backing_request_endio);
 808
 809                 /* XXX: invalidate cache */
 810
 811                 /* I/O request sent to backing device */
 812                 closure_bio_submit(s->iop.c, bio, cl);
 813         }
 814
 815         continue_at(cl, cached_dev_read_error_done, NULL);
 816 }
 817
 818 static CLOSURE_CALLBACK(cached_dev_cache_miss_done)
 819 {
 820         closure_type(s, struct search, cl);
 821         struct bcache_device *d = s->d;
 822
 823         if (s->iop.replace_collision)
 824                 bch_mark_cache_miss_collision(s->iop.c, s->d);
 825
 826         if (s->iop.bio)
 827                 bio_free_pages(s->iop.bio);
 828
 829         cached_dev_bio_complete(&cl->work);
 830         closure_put(&d->cl);
 831 }
 832
 833 static CLOSURE_CALLBACK(cached_dev_read_done)
 834 {
 835         closure_type(s, struct search, cl);
 836         struct cached_dev *dc = container_of(s->d, struct cached_dev, disk);
 837
 838         /*
 839          * We had a cache miss; cache_bio now contains data ready to be inserted
 840          * into the cache.
 841          *
 842          * First, we copy the data we just read from cache_bio's bounce buffers
 843          * to the buffers the original bio pointed to:
 844          */
 845
 846         if (s->iop.bio) {
 847                 bio_reset(s->iop.bio, s->cache_miss->bi_bdev, REQ_OP_READ);
 848                 s->iop.bio->bi_iter.bi_sector =
 849                         s->cache_miss->bi_iter.bi_sector;
 850                 s->iop.bio->bi_iter.bi_size = s->insert_bio_sectors << 9;
 851                 bio_clone_blkg_association(s->iop.bio, s->cache_miss);
 852                 bch_bio_map(s->iop.bio, NULL);
 853
 854                 bio_copy_data(s->cache_miss, s->iop.bio);
 855
 856                 bio_put(s->cache_miss);
 857                 s->cache_miss = NULL;
 858         }
 859
 860         if (verify(dc) && s->recoverable && !s->read_dirty_data)
 861                 bch_data_verify(dc, s->orig_bio);
 862
 863         closure_get(&dc->disk.cl);
 864         bio_complete(s);
 865
 866         if (s->iop.bio &&
 867             !test_bit(CACHE_SET_STOPPING, &s->iop.c->flags)) {
 868                 BUG_ON(!s->iop.replace);
 869                 closure_call(&s->iop.cl, bch_data_insert, NULL, cl);
 870         }
 871
 872         continue_at(cl, cached_dev_cache_miss_done, NULL);
 873 }
 874
 875 static CLOSURE_CALLBACK(cached_dev_read_done_bh)
 876 {
 877         closure_type(s, struct search, cl);
 878         struct cached_dev *dc = container_of(s->d, struct cached_dev, disk);
 879
 880         bch_mark_cache_accounting(s->iop.c, s->d,
 881                                   !s->cache_missed, s->iop.bypass);
 882         trace_bcache_read(s->orig_bio, !s->cache_missed, s->iop.bypass);
 883
 884         if (s->iop.status)
 885                 continue_at_nobarrier(cl, cached_dev_read_error, bcache_wq);
 886         else if (s->iop.bio || verify(dc))
 887                 continue_at_nobarrier(cl, cached_dev_read_done, bcache_wq);
 888         else
 889                 continue_at_nobarrier(cl, cached_dev_bio_complete, NULL);
 890 }
 891
 892 static int cached_dev_cache_miss(struct btree *b, struct search *s,
 893                                  struct bio *bio, unsigned int sectors)
 894 {
 895         int ret = MAP_CONTINUE;
 896         struct cached_dev *dc = container_of(s->d, struct cached_dev, disk);
 897         struct bio *miss, *cache_bio;
 898         unsigned int size_limit;
 899
 900         s->cache_missed = 1;
 901
 902         if (s->cache_miss || s->iop.bypass) {
 903                 miss = bio_next_split(bio, sectors, GFP_NOIO, &s->d->bio_split);
 904                 ret = miss == bio ? MAP_DONE : MAP_CONTINUE;
 905                 goto out_submit;
 906         }
 907
 908         /* Limitation for valid replace key size and cache_bio bvecs number */
 909         size_limit = min_t(unsigned int, BIO_MAX_VECS * PAGE_SECTORS,
 910                            (1 << KEY_SIZE_BITS) - 1);
 911         s->insert_bio_sectors = min3(size_limit, sectors, bio_sectors(bio));
 912
 913         s->iop.replace_key = KEY(s->iop.inode,
 914                                  bio->bi_iter.bi_sector + s->insert_bio_sectors,
 915                                  s->insert_bio_sectors);
 916
 917         ret = bch_btree_insert_check_key(b, &s->op, &s->iop.replace_key);
 918         if (ret)
 919                 return ret;
 920
 921         s->iop.replace = true;
 922
 923         miss = bio_next_split(bio, s->insert_bio_sectors, GFP_NOIO,
 924                               &s->d->bio_split);
 925
 926         /* btree_search_recurse()'s btree iterator is no good anymore */
 927         ret = miss == bio ? MAP_DONE : -EINTR;
 928
 929         cache_bio = bio_alloc_bioset(miss->bi_bdev,
 930                         DIV_ROUND_UP(s->insert_bio_sectors, PAGE_SECTORS),
 931                         0, GFP_NOWAIT, &dc->disk.bio_split);
 932         if (!cache_bio)
 933                 goto out_submit;
 934
 935         cache_bio->bi_iter.bi_sector    = miss->bi_iter.bi_sector;
 936         cache_bio->bi_iter.bi_size      = s->insert_bio_sectors << 9;
 937
 938         cache_bio->bi_end_io    = backing_request_endio;
 939         cache_bio->bi_private   = &s->cl;
 940
 941         bch_bio_map(cache_bio, NULL);
 942         if (bch_bio_alloc_pages(cache_bio, __GFP_NOWARN|GFP_NOIO))
 943                 goto out_put;
 944
 945         s->cache_miss   = miss;
 946         s->iop.bio      = cache_bio;
 947         bio_get(cache_bio);
 948         /* I/O request sent to backing device */
 949         closure_bio_submit(s->iop.c, cache_bio, &s->cl);
 950
 951         return ret;
 952 out_put:
 953         bio_put(cache_bio);
 954 out_submit:
 955         miss->bi_end_io         = backing_request_endio;
 956         miss->bi_private        = &s->cl;
 957         /* I/O request sent to backing device */
 958         closure_bio_submit(s->iop.c, miss, &s->cl);
 959         return ret;
 960 }
 961
 962 static void cached_dev_read(struct cached_dev *dc, struct search *s)
 963 {
 964         struct closure *cl = &s->cl;
 965
 966         closure_call(&s->iop.cl, cache_lookup, NULL, cl);
 967         continue_at(cl, cached_dev_read_done_bh, NULL);
 968 }
 969
 970 /* Process writes */
 971
 972 static CLOSURE_CALLBACK(cached_dev_write_complete)
 973 {
 974         closure_type(s, struct search, cl);
 975         struct cached_dev *dc = container_of(s->d, struct cached_dev, disk);
 976
 977         up_read_non_owner(&dc->writeback_lock);
 978         cached_dev_bio_complete(&cl->work);
 979 }
 980
 981 static void cached_dev_write(struct cached_dev *dc, struct search *s)
 982 {
 983         struct closure *cl = &s->cl;
 984         struct bio *bio = &s->bio.bio;
 985         struct bkey start = KEY(dc->disk.id, bio->bi_iter.bi_sector, 0);
 986         struct bkey end = KEY(dc->disk.id, bio_end_sector(bio), 0);
 987
 988         bch_keybuf_check_overlapping(&s->iop.c->moving_gc_keys, &start, &end);
 989
 990         down_read_non_owner(&dc->writeback_lock);
 991         if (bch_keybuf_check_overlapping(&dc->writeback_keys, &start, &end)) {
 992                 /*
 993                  * We overlap with some dirty data undergoing background
 994                  * writeback, force this write to writeback
 995                  */
 996                 s->iop.bypass = false;
 997                 s->iop.writeback = true;
 998         }
 999
1000         /*
1001          * Discards aren't _required_ to do anything, so skipping if
1002          * check_overlapping returned true is ok
1003          *
1004          * But check_overlapping drops dirty keys for which io hasn't started,
1005          * so we still want to call it.
1006          */
1007         if (bio_op(bio) == REQ_OP_DISCARD)
1008                 s->iop.bypass = true;
1009
1010         if (should_writeback(dc, s->orig_bio,
1011                              cache_mode(dc),
1012                              s->iop.bypass)) {
1013                 s->iop.bypass = false;
1014                 s->iop.writeback = true;
1015         }
1016
1017         if (s->iop.bypass) {
1018                 s->iop.bio = s->orig_bio;
1019                 bio_get(s->iop.bio);
1020
1021                 if (bio_op(bio) == REQ_OP_DISCARD &&
1022                     !bdev_max_discard_sectors(dc->bdev))
1023                         goto insert_data;
1024
1025                 /* I/O request sent to backing device */
1026                 bio->bi_end_io = backing_request_endio;
1027                 closure_bio_submit(s->iop.c, bio, cl);
1028
1029         } else if (s->iop.writeback) {
1030                 bch_writeback_add(dc);
1031                 s->iop.bio = bio;
1032
1033                 if (bio->bi_opf & REQ_PREFLUSH) {
1034                         /*
1035                          * Also need to send a flush to the backing
1036                          * device.
1037                          */
1038                         struct bio *flush;
1039
1040                         flush = bio_alloc_bioset(bio->bi_bdev, 0,
1041                                                  REQ_OP_WRITE | REQ_PREFLUSH,
1042                                                  GFP_NOIO, &dc->disk.bio_split);
1043                         if (!flush) {
1044                                 s->iop.status = BLK_STS_RESOURCE;
1045                                 goto insert_data;
1046                         }
1047                         flush->bi_end_io = backing_request_endio;
1048                         flush->bi_private = cl;
1049                         /* I/O request sent to backing device */
1050                         closure_bio_submit(s->iop.c, flush, cl);
1051                 }
1052         } else {
1053                 s->iop.bio = bio_alloc_clone(bio->bi_bdev, bio, GFP_NOIO,
1054                                              &dc->disk.bio_split);
1055                 /* I/O request sent to backing device */
1056                 bio->bi_end_io = backing_request_endio;
1057                 closure_bio_submit(s->iop.c, bio, cl);
1058         }
1059
1060 insert_data:
1061         closure_call(&s->iop.cl, bch_data_insert, NULL, cl);
1062         continue_at(cl, cached_dev_write_complete, NULL);
1063 }
1064
1065 static CLOSURE_CALLBACK(cached_dev_nodata)
1066 {
1067         closure_type(s, struct search, cl);
1068         struct bio *bio = &s->bio.bio;
1069
1070         if (s->iop.flush_journal)
1071                 bch_journal_meta(s->iop.c, cl);
1072
1073         /* If it's a flush, we send the flush to the backing device too */
1074         bio->bi_end_io = backing_request_endio;
1075         closure_bio_submit(s->iop.c, bio, cl);
1076
1077         continue_at(cl, cached_dev_bio_complete, NULL);
1078 }
1079
1080 struct detached_dev_io_private {
1081         struct bcache_device    *d;
1082         unsigned long           start_time;
1083         bio_end_io_t            *bi_end_io;
1084         void                    *bi_private;
1085         struct block_device     *orig_bdev;
1086 };
1087
1088 static void detached_dev_end_io(struct bio *bio)
1089 {
1090         struct detached_dev_io_private *ddip;
1091
1092         ddip = bio->bi_private;
1093         bio->bi_end_io = ddip->bi_end_io;
1094         bio->bi_private = ddip->bi_private;
1095
1096         /* Count on the bcache device */
1097         bio_end_io_acct_remapped(bio, ddip->start_time, ddip->orig_bdev);
1098
1099         if (bio->bi_status) {
1100                 struct cached_dev *dc = container_of(ddip->d,
1101                                                      struct cached_dev, disk);
1102                 /* should count I/O error for backing device here */
1103                 bch_count_backing_io_errors(dc, bio);
1104         }
1105
1106         kfree(ddip);
1107         bio->bi_end_io(bio);
1108 }
1109
1110 static void detached_dev_do_request(struct bcache_device *d, struct bio *bio,
1111                 struct block_device *orig_bdev, unsigned long start_time)
1112 {
1113         struct detached_dev_io_private *ddip;
1114         struct cached_dev *dc = container_of(d, struct cached_dev, disk);
1115
1116         /*
1117          * no need to call closure_get(&dc->disk.cl),
1118          * because upper layer had already opened bcache device,
1119          * which would call closure_get(&dc->disk.cl)
1120          */
1121         ddip = kzalloc(sizeof(struct detached_dev_io_private), GFP_NOIO);
1122         if (!ddip) {
1123                 bio->bi_status = BLK_STS_RESOURCE;
1124                 bio->bi_end_io(bio);
1125                 return;
1126         }
1127
1128         ddip->d = d;
1129         /* Count on the bcache device */
1130         ddip->orig_bdev = orig_bdev;
1131         ddip->start_time = start_time;
1132         ddip->bi_end_io = bio->bi_end_io;
1133         ddip->bi_private = bio->bi_private;
1134         bio->bi_end_io = detached_dev_end_io;
1135         bio->bi_private = ddip;
1136
1137         if ((bio_op(bio) == REQ_OP_DISCARD) &&
1138             !bdev_max_discard_sectors(dc->bdev))
1139                 bio->bi_end_io(bio);
1140         else
1141                 submit_bio_noacct(bio);
1142 }
1143
1144 static void quit_max_writeback_rate(struct cache_set *c,
1145                                     struct cached_dev *this_dc)
1146 {
1147         int i;
1148         struct bcache_device *d;
1149         struct cached_dev *dc;
1150
1151         /*
1152          * mutex bch_register_lock may compete with other parallel requesters,
1153          * or attach/detach operations on other backing device. Waiting to
1154          * the mutex lock may increase I/O request latency for seconds or more.
1155          * To avoid such situation, if mutext_trylock() failed, only writeback
1156          * rate of current cached device is set to 1, and __update_write_back()
1157          * will decide writeback rate of other cached devices (remember now
1158          * c->idle_counter is 0 already).
1159          */
1160         if (mutex_trylock(&bch_register_lock)) {
1161                 for (i = 0; i < c->devices_max_used; i++) {
1162                         if (!c->devices[i])
1163                                 continue;
1164
1165                         if (UUID_FLASH_ONLY(&c->uuids[i]))
1166                                 continue;
1167
1168                         d = c->devices[i];
1169                         dc = container_of(d, struct cached_dev, disk);
1170                         /*
1171                          * set writeback rate to default minimum value,
1172                          * then let update_writeback_rate() to decide the
1173                          * upcoming rate.
1174                          */
1175                         atomic_long_set(&dc->writeback_rate.rate, 1);
1176                 }
1177                 mutex_unlock(&bch_register_lock);
1178         } else
1179                 atomic_long_set(&this_dc->writeback_rate.rate, 1);
1180 }
1181
1182 /* Cached devices - read & write stuff */
1183
1184 void cached_dev_submit_bio(struct bio *bio)
1185 {
1186         struct search *s;
1187         struct block_device *orig_bdev = bio->bi_bdev;
1188         struct bcache_device *d = orig_bdev->bd_disk->private_data;
1189         struct cached_dev *dc = container_of(d, struct cached_dev, disk);
1190         unsigned long start_time;
1191         int rw = bio_data_dir(bio);
1192
1193         if (unlikely((d->c && test_bit(CACHE_SET_IO_DISABLE, &d->c->flags)) ||
1194                      dc->io_disable)) {
1195                 bio->bi_status = BLK_STS_IOERR;
1196                 bio_endio(bio);
1197                 return;
1198         }
1199
1200         if (likely(d->c)) {
1201                 if (atomic_read(&d->c->idle_counter))
1202                         atomic_set(&d->c->idle_counter, 0);
1203                 /*
1204                  * If at_max_writeback_rate of cache set is true and new I/O
1205                  * comes, quit max writeback rate of all cached devices
1206                  * attached to this cache set, and set at_max_writeback_rate
1207                  * to false.
1208                  */
1209                 if (unlikely(atomic_read(&d->c->at_max_writeback_rate) == 1)) {
1210                         atomic_set(&d->c->at_max_writeback_rate, 0);
1211                         quit_max_writeback_rate(d->c, dc);
1212                 }
1213         }
1214
1215         start_time = bio_start_io_acct(bio);
1216
1217         bio_set_dev(bio, dc->bdev);
1218         bio->bi_iter.bi_sector += dc->sb.data_offset;
1219
1220         if (cached_dev_get(dc)) {
1221                 s = search_alloc(bio, d, orig_bdev, start_time);
1222                 trace_bcache_request_start(s->d, bio);
1223
1224                 if (!bio->bi_iter.bi_size) {
1225                         /*
1226                          * can't call bch_journal_meta from under
1227                          * submit_bio_noacct
1228                          */
1229                         continue_at_nobarrier(&s->cl,
1230                                               cached_dev_nodata,
1231                                               bcache_wq);
1232                 } else {
1233                         s->iop.bypass = check_should_bypass(dc, bio);
1234
1235                         if (rw)
1236                                 cached_dev_write(dc, s);
1237                         else
1238                                 cached_dev_read(dc, s);
1239                 }
1240         } else
1241                 /* I/O request sent to backing device */
1242                 detached_dev_do_request(d, bio, orig_bdev, start_time);
1243 }
1244
1245 static int cached_dev_ioctl(struct bcache_device *d, blk_mode_t mode,
1246                             unsigned int cmd, unsigned long arg)
1247 {
1248         struct cached_dev *dc = container_of(d, struct cached_dev, disk);
1249
1250         if (dc->io_disable)
1251                 return -EIO;
1252         if (!dc->bdev->bd_disk->fops->ioctl)
1253                 return -ENOTTY;
1254         return dc->bdev->bd_disk->fops->ioctl(dc->bdev, mode, cmd, arg);
1255 }
1256
1257 void bch_cached_dev_request_init(struct cached_dev *dc)
1258 {
1259         dc->disk.cache_miss                     = cached_dev_cache_miss;
1260         dc->disk.ioctl                          = cached_dev_ioctl;
1261 }
1262
1263 /* Flash backed devices */
1264
1265 static int flash_dev_cache_miss(struct btree *b, struct search *s,
1266                                 struct bio *bio, unsigned int sectors)
1267 {
1268         unsigned int bytes = min(sectors, bio_sectors(bio)) << 9;
1269
1270         swap(bio->bi_iter.bi_size, bytes);
1271         zero_fill_bio(bio);
1272         swap(bio->bi_iter.bi_size, bytes);
1273
1274         bio_advance(bio, bytes);
1275
1276         if (!bio->bi_iter.bi_size)
1277                 return MAP_DONE;
1278
1279         return MAP_CONTINUE;
1280 }
1281
1282 static CLOSURE_CALLBACK(flash_dev_nodata)
1283 {
1284         closure_type(s, struct search, cl);
1285
1286         if (s->iop.flush_journal)
1287                 bch_journal_meta(s->iop.c, cl);
1288
1289         continue_at(cl, search_free, NULL);
1290 }
1291
1292 void flash_dev_submit_bio(struct bio *bio)
1293 {
1294         struct search *s;
1295         struct closure *cl;
1296         struct bcache_device *d = bio->bi_bdev->bd_disk->private_data;
1297
1298         if (unlikely(d->c && test_bit(CACHE_SET_IO_DISABLE, &d->c->flags))) {
1299                 bio->bi_status = BLK_STS_IOERR;
1300                 bio_endio(bio);
1301                 return;
1302         }
1303
1304         s = search_alloc(bio, d, bio->bi_bdev, bio_start_io_acct(bio));
1305         cl = &s->cl;
1306         bio = &s->bio.bio;
1307
1308         trace_bcache_request_start(s->d, bio);
1309
1310         if (!bio->bi_iter.bi_size) {
1311                 /*
1312                  * can't call bch_journal_meta from under submit_bio_noacct
1313                  */
1314                 continue_at_nobarrier(&s->cl,
1315                                       flash_dev_nodata,
1316                                       bcache_wq);
1317                 return;
1318         } else if (bio_data_dir(bio)) {
1319                 bch_keybuf_check_overlapping(&s->iop.c->moving_gc_keys,
1320                                         &KEY(d->id, bio->bi_iter.bi_sector, 0),
1321                                         &KEY(d->id, bio_end_sector(bio), 0));
1322
1323                 s->iop.bypass           = (bio_op(bio) == REQ_OP_DISCARD) != 0;
1324                 s->iop.writeback        = true;
1325                 s->iop.bio              = bio;
1326
1327                 closure_call(&s->iop.cl, bch_data_insert, NULL, cl);
1328         } else {
1329                 closure_call(&s->iop.cl, cache_lookup, NULL, cl);
1330         }
1331
1332         continue_at(cl, search_free, NULL);
1333 }
1334
1335 static int flash_dev_ioctl(struct bcache_device *d, blk_mode_t mode,
1336                            unsigned int cmd, unsigned long arg)
1337 {
1338         return -ENOTTY;
1339 }
1340
1341 void bch_flash_dev_request_init(struct bcache_device *d)
1342 {
1343         d->cache_miss                           = flash_dev_cache_miss;
1344         d->ioctl                                = flash_dev_ioctl;
1345 }
1346
1347 void bch_request_exit(void)
1348 {
1349         kmem_cache_destroy(bch_search_cache);
1350 }
1351
1352 int __init bch_request_init(void)
1353 {
1354         bch_search_cache = KMEM_CACHE(search, 0);
1355         if (!bch_search_cache)
1356                 return -ENOMEM;
1357
1358         return 0;
1359 }