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

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Some low level IO code, and hacks for various block layer limitations
   4  *
   5  * Copyright 2010, 2011 Kent Overstreet <kent.overstreet@gmail.com>
   6  * Copyright 2012 Google, Inc.
   7  */
   8
   9 #include "bcachefs.h"
  10 #include "alloc_background.h"
  11 #include "alloc_foreground.h"
  12 #include "btree_update.h"
  13 #include "buckets.h"
  14 #include "checksum.h"
  15 #include "clock.h"
  16 #include "compress.h"
  17 #include "data_update.h"
  18 #include "disk_groups.h"
  19 #include "ec.h"
  20 #include "error.h"
  21 #include "io_read.h"
  22 #include "io_misc.h"
  23 #include "io_write.h"
  24 #include "subvolume.h"
  25 #include "trace.h"
  26
  27 #include <linux/sched/mm.h>
  28
  29 #ifndef CONFIG_BCACHEFS_NO_LATENCY_ACCT
  30
  31 static bool bch2_target_congested(struct bch_fs *c, u16 target)
  32 {
  33         const struct bch_devs_mask *devs;
  34         unsigned d, nr = 0, total = 0;
  35         u64 now = local_clock(), last;
  36         s64 congested;
  37         struct bch_dev *ca;
  38
  39         if (!target)
  40                 return false;
  41
  42         rcu_read_lock();
  43         devs = bch2_target_to_mask(c, target) ?:
  44                 &c->rw_devs[BCH_DATA_user];
  45
  46         for_each_set_bit(d, devs->d, BCH_SB_MEMBERS_MAX) {
  47                 ca = rcu_dereference(c->devs[d]);
  48                 if (!ca)
  49                         continue;
  50
  51                 congested = atomic_read(&ca->congested);
  52                 last = READ_ONCE(ca->congested_last);
  53                 if (time_after64(now, last))
  54                         congested -= (now - last) >> 12;
  55
  56                 total += max(congested, 0LL);
  57                 nr++;
  58         }
  59         rcu_read_unlock();
  60
  61         return bch2_rand_range(nr * CONGESTED_MAX) < total;
  62 }
  63
  64 #else
  65
  66 static bool bch2_target_congested(struct bch_fs *c, u16 target)
  67 {
  68         return false;
  69 }
  70
  71 #endif
  72
  73 /* Cache promotion on read */
  74
  75 struct promote_op {
  76         struct rcu_head         rcu;
  77         u64                     start_time;
  78
  79         struct rhash_head       hash;
  80         struct bpos             pos;
  81
  82         struct data_update      write;
  83         struct bio_vec          bi_inline_vecs[0]; /* must be last */
  84 };
  85
  86 static const struct rhashtable_params bch_promote_params = {
  87         .head_offset    = offsetof(struct promote_op, hash),
  88         .key_offset     = offsetof(struct promote_op, pos),
  89         .key_len        = sizeof(struct bpos),
  90 };
  91
  92 static inline int should_promote(struct bch_fs *c, struct bkey_s_c k,
  93                                   struct bpos pos,
  94                                   struct bch_io_opts opts,
  95                                   unsigned flags)
  96 {
  97         BUG_ON(!opts.promote_target);
  98
  99         if (!(flags & BCH_READ_MAY_PROMOTE))
 100                 return -BCH_ERR_nopromote_may_not;
 101
 102         if (bch2_bkey_has_target(c, k, opts.promote_target))
 103                 return -BCH_ERR_nopromote_already_promoted;
 104
 105         if (bkey_extent_is_unwritten(k))
 106                 return -BCH_ERR_nopromote_unwritten;
 107
 108         if (bch2_target_congested(c, opts.promote_target))
 109                 return -BCH_ERR_nopromote_congested;
 110
 111         if (rhashtable_lookup_fast(&c->promote_table, &pos,
 112                                    bch_promote_params))
 113                 return -BCH_ERR_nopromote_in_flight;
 114
 115         return 0;
 116 }
 117
 118 static void promote_free(struct bch_fs *c, struct promote_op *op)
 119 {
 120         int ret;
 121
 122         bch2_data_update_exit(&op->write);
 123
 124         ret = rhashtable_remove_fast(&c->promote_table, &op->hash,
 125                                      bch_promote_params);
 126         BUG_ON(ret);
 127         bch2_write_ref_put(c, BCH_WRITE_REF_promote);
 128         kfree_rcu(op, rcu);
 129 }
 130
 131 static void promote_done(struct bch_write_op *wop)
 132 {
 133         struct promote_op *op =
 134                 container_of(wop, struct promote_op, write.op);
 135         struct bch_fs *c = op->write.op.c;
 136
 137         bch2_time_stats_update(&c->times[BCH_TIME_data_promote],
 138                                op->start_time);
 139         promote_free(c, op);
 140 }
 141
 142 static void promote_start(struct promote_op *op, struct bch_read_bio *rbio)
 143 {
 144         struct bio *bio = &op->write.op.wbio.bio;
 145
 146         trace_and_count(op->write.op.c, read_promote, &rbio->bio);
 147
 148         /* we now own pages: */
 149         BUG_ON(!rbio->bounce);
 150         BUG_ON(rbio->bio.bi_vcnt > bio->bi_max_vecs);
 151
 152         memcpy(bio->bi_io_vec, rbio->bio.bi_io_vec,
 153                sizeof(struct bio_vec) * rbio->bio.bi_vcnt);
 154         swap(bio->bi_vcnt, rbio->bio.bi_vcnt);
 155
 156         bch2_data_update_read_done(&op->write, rbio->pick.crc);
 157 }
 158
 159 static struct promote_op *__promote_alloc(struct btree_trans *trans,
 160                                           enum btree_id btree_id,
 161                                           struct bkey_s_c k,
 162                                           struct bpos pos,
 163                                           struct extent_ptr_decoded *pick,
 164                                           struct bch_io_opts opts,
 165                                           unsigned sectors,
 166                                           struct bch_read_bio **rbio)
 167 {
 168         struct bch_fs *c = trans->c;
 169         struct promote_op *op = NULL;
 170         struct bio *bio;
 171         unsigned pages = DIV_ROUND_UP(sectors, PAGE_SECTORS);
 172         int ret;
 173
 174         if (!bch2_write_ref_tryget(c, BCH_WRITE_REF_promote))
 175                 return NULL;
 176
 177         op = kzalloc(sizeof(*op) + sizeof(struct bio_vec) * pages, GFP_NOFS);
 178         if (!op)
 179                 goto err;
 180
 181         op->start_time = local_clock();
 182         op->pos = pos;
 183
 184         /*
 185          * We don't use the mempool here because extents that aren't
 186          * checksummed or compressed can be too big for the mempool:
 187          */
 188         *rbio = kzalloc(sizeof(struct bch_read_bio) +
 189                         sizeof(struct bio_vec) * pages,
 190                         GFP_NOFS);
 191         if (!*rbio)
 192                 goto err;
 193
 194         rbio_init(&(*rbio)->bio, opts);
 195         bio_init(&(*rbio)->bio, NULL, (*rbio)->bio.bi_inline_vecs, pages, 0);
 196
 197         if (bch2_bio_alloc_pages(&(*rbio)->bio, sectors << 9,
 198                                  GFP_NOFS))
 199                 goto err;
 200
 201         (*rbio)->bounce         = true;
 202         (*rbio)->split          = true;
 203         (*rbio)->kmalloc        = true;
 204
 205         if (rhashtable_lookup_insert_fast(&c->promote_table, &op->hash,
 206                                           bch_promote_params))
 207                 goto err;
 208
 209         bio = &op->write.op.wbio.bio;
 210         bio_init(bio, NULL, bio->bi_inline_vecs, pages, 0);
 211
 212         ret = bch2_data_update_init(trans, NULL, &op->write,
 213                         writepoint_hashed((unsigned long) current),
 214                         opts,
 215                         (struct data_update_opts) {
 216                                 .target         = opts.promote_target,
 217                                 .extra_replicas = 1,
 218                                 .write_flags    = BCH_WRITE_ALLOC_NOWAIT|BCH_WRITE_CACHED,
 219                         },
 220                         btree_id, k);
 221         /*
 222          * possible errors: -BCH_ERR_nocow_lock_blocked,
 223          * -BCH_ERR_ENOSPC_disk_reservation:
 224          */
 225         if (ret) {
 226                 ret = rhashtable_remove_fast(&c->promote_table, &op->hash,
 227                                         bch_promote_params);
 228                 BUG_ON(ret);
 229                 goto err;
 230         }
 231
 232         op->write.op.end_io = promote_done;
 233
 234         return op;
 235 err:
 236         if (*rbio)
 237                 bio_free_pages(&(*rbio)->bio);
 238         kfree(*rbio);
 239         *rbio = NULL;
 240         kfree(op);
 241         bch2_write_ref_put(c, BCH_WRITE_REF_promote);
 242         return NULL;
 243 }
 244
 245 noinline
 246 static struct promote_op *promote_alloc(struct btree_trans *trans,
 247                                         struct bvec_iter iter,
 248                                         struct bkey_s_c k,
 249                                         struct extent_ptr_decoded *pick,
 250                                         struct bch_io_opts opts,
 251                                         unsigned flags,
 252                                         struct bch_read_bio **rbio,
 253                                         bool *bounce,
 254                                         bool *read_full)
 255 {
 256         struct bch_fs *c = trans->c;
 257         bool promote_full = *read_full || READ_ONCE(c->promote_whole_extents);
 258         /* data might have to be decompressed in the write path: */
 259         unsigned sectors = promote_full
 260                 ? max(pick->crc.compressed_size, pick->crc.live_size)
 261                 : bvec_iter_sectors(iter);
 262         struct bpos pos = promote_full
 263                 ? bkey_start_pos(k.k)
 264                 : POS(k.k->p.inode, iter.bi_sector);
 265         struct promote_op *promote;
 266         int ret;
 267
 268         ret = should_promote(c, k, pos, opts, flags);
 269         if (ret)
 270                 goto nopromote;
 271
 272         promote = __promote_alloc(trans,
 273                                   k.k->type == KEY_TYPE_reflink_v
 274                                   ? BTREE_ID_reflink
 275                                   : BTREE_ID_extents,
 276                                   k, pos, pick, opts, sectors, rbio);
 277         if (!promote) {
 278                 ret = -BCH_ERR_nopromote_enomem;
 279                 goto nopromote;
 280         }
 281
 282         *bounce         = true;
 283         *read_full      = promote_full;
 284         return promote;
 285 nopromote:
 286         trace_read_nopromote(c, ret);
 287         return NULL;
 288 }
 289
 290 /* Read */
 291
 292 #define READ_RETRY_AVOID        1
 293 #define READ_RETRY              2
 294 #define READ_ERR                3
 295
 296 enum rbio_context {
 297         RBIO_CONTEXT_NULL,
 298         RBIO_CONTEXT_HIGHPRI,
 299         RBIO_CONTEXT_UNBOUND,
 300 };
 301
 302 static inline struct bch_read_bio *
 303 bch2_rbio_parent(struct bch_read_bio *rbio)
 304 {
 305         return rbio->split ? rbio->parent : rbio;
 306 }
 307
 308 __always_inline
 309 static void bch2_rbio_punt(struct bch_read_bio *rbio, work_func_t fn,
 310                            enum rbio_context context,
 311                            struct workqueue_struct *wq)
 312 {
 313         if (context <= rbio->context) {
 314                 fn(&rbio->work);
 315         } else {
 316                 rbio->work.func         = fn;
 317                 rbio->context           = context;
 318                 queue_work(wq, &rbio->work);
 319         }
 320 }
 321
 322 static inline struct bch_read_bio *bch2_rbio_free(struct bch_read_bio *rbio)
 323 {
 324         BUG_ON(rbio->bounce && !rbio->split);
 325
 326         if (rbio->promote)
 327                 promote_free(rbio->c, rbio->promote);
 328         rbio->promote = NULL;
 329
 330         if (rbio->bounce)
 331                 bch2_bio_free_pages_pool(rbio->c, &rbio->bio);
 332
 333         if (rbio->split) {
 334                 struct bch_read_bio *parent = rbio->parent;
 335
 336                 if (rbio->kmalloc)
 337                         kfree(rbio);
 338                 else
 339                         bio_put(&rbio->bio);
 340
 341                 rbio = parent;
 342         }
 343
 344         return rbio;
 345 }
 346
 347 /*
 348  * Only called on a top level bch_read_bio to complete an entire read request,
 349  * not a split:
 350  */
 351 static void bch2_rbio_done(struct bch_read_bio *rbio)
 352 {
 353         if (rbio->start_time)
 354                 bch2_time_stats_update(&rbio->c->times[BCH_TIME_data_read],
 355                                        rbio->start_time);
 356         bio_endio(&rbio->bio);
 357 }
 358
 359 static void bch2_read_retry_nodecode(struct bch_fs *c, struct bch_read_bio *rbio,
 360                                      struct bvec_iter bvec_iter,
 361                                      struct bch_io_failures *failed,
 362                                      unsigned flags)
 363 {
 364         struct btree_trans *trans = bch2_trans_get(c);
 365         struct btree_iter iter;
 366         struct bkey_buf sk;
 367         struct bkey_s_c k;
 368         int ret;
 369
 370         flags &= ~BCH_READ_LAST_FRAGMENT;
 371         flags |= BCH_READ_MUST_CLONE;
 372
 373         bch2_bkey_buf_init(&sk);
 374
 375         bch2_trans_iter_init(trans, &iter, rbio->data_btree,
 376                              rbio->read_pos, BTREE_ITER_SLOTS);
 377 retry:
 378         rbio->bio.bi_status = 0;
 379
 380         k = bch2_btree_iter_peek_slot(&iter);
 381         if (bkey_err(k))
 382                 goto err;
 383
 384         bch2_bkey_buf_reassemble(&sk, c, k);
 385         k = bkey_i_to_s_c(sk.k);
 386         bch2_trans_unlock(trans);
 387
 388         if (!bch2_bkey_matches_ptr(c, k,
 389                                    rbio->pick.ptr,
 390                                    rbio->data_pos.offset -
 391                                    rbio->pick.crc.offset)) {
 392                 /* extent we wanted to read no longer exists: */
 393                 rbio->hole = true;
 394                 goto out;
 395         }
 396
 397         ret = __bch2_read_extent(trans, rbio, bvec_iter,
 398                                  rbio->read_pos,
 399                                  rbio->data_btree,
 400                                  k, 0, failed, flags);
 401         if (ret == READ_RETRY)
 402                 goto retry;
 403         if (ret)
 404                 goto err;
 405 out:
 406         bch2_rbio_done(rbio);
 407         bch2_trans_iter_exit(trans, &iter);
 408         bch2_trans_put(trans);
 409         bch2_bkey_buf_exit(&sk, c);
 410         return;
 411 err:
 412         rbio->bio.bi_status = BLK_STS_IOERR;
 413         goto out;
 414 }
 415
 416 static void bch2_rbio_retry(struct work_struct *work)
 417 {
 418         struct bch_read_bio *rbio =
 419                 container_of(work, struct bch_read_bio, work);
 420         struct bch_fs *c        = rbio->c;
 421         struct bvec_iter iter   = rbio->bvec_iter;
 422         unsigned flags          = rbio->flags;
 423         subvol_inum inum = {
 424                 .subvol = rbio->subvol,
 425                 .inum   = rbio->read_pos.inode,
 426         };
 427         struct bch_io_failures failed = { .nr = 0 };
 428
 429         trace_and_count(c, read_retry, &rbio->bio);
 430
 431         if (rbio->retry == READ_RETRY_AVOID)
 432                 bch2_mark_io_failure(&failed, &rbio->pick);
 433
 434         rbio->bio.bi_status = 0;
 435
 436         rbio = bch2_rbio_free(rbio);
 437
 438         flags |= BCH_READ_IN_RETRY;
 439         flags &= ~BCH_READ_MAY_PROMOTE;
 440
 441         if (flags & BCH_READ_NODECODE) {
 442                 bch2_read_retry_nodecode(c, rbio, iter, &failed, flags);
 443         } else {
 444                 flags &= ~BCH_READ_LAST_FRAGMENT;
 445                 flags |= BCH_READ_MUST_CLONE;
 446
 447                 __bch2_read(c, rbio, iter, inum, &failed, flags);
 448         }
 449 }
 450
 451 static void bch2_rbio_error(struct bch_read_bio *rbio, int retry,
 452                             blk_status_t error)
 453 {
 454         rbio->retry = retry;
 455
 456         if (rbio->flags & BCH_READ_IN_RETRY)
 457                 return;
 458
 459         if (retry == READ_ERR) {
 460                 rbio = bch2_rbio_free(rbio);
 461
 462                 rbio->bio.bi_status = error;
 463                 bch2_rbio_done(rbio);
 464         } else {
 465                 bch2_rbio_punt(rbio, bch2_rbio_retry,
 466                                RBIO_CONTEXT_UNBOUND, system_unbound_wq);
 467         }
 468 }
 469
 470 static int __bch2_rbio_narrow_crcs(struct btree_trans *trans,
 471                                    struct bch_read_bio *rbio)
 472 {
 473         struct bch_fs *c = rbio->c;
 474         u64 data_offset = rbio->data_pos.offset - rbio->pick.crc.offset;
 475         struct bch_extent_crc_unpacked new_crc;
 476         struct btree_iter iter;
 477         struct bkey_i *new;
 478         struct bkey_s_c k;
 479         int ret = 0;
 480
 481         if (crc_is_compressed(rbio->pick.crc))
 482                 return 0;
 483
 484         k = bch2_bkey_get_iter(trans, &iter, rbio->data_btree, rbio->data_pos,
 485                                BTREE_ITER_SLOTS|BTREE_ITER_INTENT);
 486         if ((ret = bkey_err(k)))
 487                 goto out;
 488
 489         if (bversion_cmp(k.k->version, rbio->version) ||
 490             !bch2_bkey_matches_ptr(c, k, rbio->pick.ptr, data_offset))
 491                 goto out;
 492
 493         /* Extent was merged? */
 494         if (bkey_start_offset(k.k) < data_offset ||
 495             k.k->p.offset > data_offset + rbio->pick.crc.uncompressed_size)
 496                 goto out;
 497
 498         if (bch2_rechecksum_bio(c, &rbio->bio, rbio->version,
 499                         rbio->pick.crc, NULL, &new_crc,
 500                         bkey_start_offset(k.k) - data_offset, k.k->size,
 501                         rbio->pick.crc.csum_type)) {
 502                 bch_err(c, "error verifying existing checksum while narrowing checksum (memory corruption?)");
 503                 ret = 0;
 504                 goto out;
 505         }
 506
 507         /*
 508          * going to be temporarily appending another checksum entry:
 509          */
 510         new = bch2_trans_kmalloc(trans, bkey_bytes(k.k) +
 511                                  sizeof(struct bch_extent_crc128));
 512         if ((ret = PTR_ERR_OR_ZERO(new)))
 513                 goto out;
 514
 515         bkey_reassemble(new, k);
 516
 517         if (!bch2_bkey_narrow_crcs(new, new_crc))
 518                 goto out;
 519
 520         ret = bch2_trans_update(trans, &iter, new,
 521                                 BTREE_UPDATE_INTERNAL_SNAPSHOT_NODE);
 522 out:
 523         bch2_trans_iter_exit(trans, &iter);
 524         return ret;
 525 }
 526
 527 static noinline void bch2_rbio_narrow_crcs(struct bch_read_bio *rbio)
 528 {
 529         bch2_trans_do(rbio->c, NULL, NULL, BCH_TRANS_COMMIT_no_enospc,
 530                       __bch2_rbio_narrow_crcs(trans, rbio));
 531 }
 532
 533 /* Inner part that may run in process context */
 534 static void __bch2_read_endio(struct work_struct *work)
 535 {
 536         struct bch_read_bio *rbio =
 537                 container_of(work, struct bch_read_bio, work);
 538         struct bch_fs *c        = rbio->c;
 539         struct bch_dev *ca      = bch_dev_bkey_exists(c, rbio->pick.ptr.dev);
 540         struct bio *src         = &rbio->bio;
 541         struct bio *dst         = &bch2_rbio_parent(rbio)->bio;
 542         struct bvec_iter dst_iter = rbio->bvec_iter;
 543         struct bch_extent_crc_unpacked crc = rbio->pick.crc;
 544         struct nonce nonce = extent_nonce(rbio->version, crc);
 545         unsigned nofs_flags;
 546         struct bch_csum csum;
 547         int ret;
 548
 549         nofs_flags = memalloc_nofs_save();
 550
 551         /* Reset iterator for checksumming and copying bounced data: */
 552         if (rbio->bounce) {
 553                 src->bi_iter.bi_size            = crc.compressed_size << 9;
 554                 src->bi_iter.bi_idx             = 0;
 555                 src->bi_iter.bi_bvec_done       = 0;
 556         } else {
 557                 src->bi_iter                    = rbio->bvec_iter;
 558         }
 559
 560         csum = bch2_checksum_bio(c, crc.csum_type, nonce, src);
 561         if (bch2_crc_cmp(csum, rbio->pick.crc.csum) && !c->opts.no_data_io)
 562                 goto csum_err;
 563
 564         /*
 565          * XXX
 566          * We need to rework the narrow_crcs path to deliver the read completion
 567          * first, and then punt to a different workqueue, otherwise we're
 568          * holding up reads while doing btree updates which is bad for memory
 569          * reclaim.
 570          */
 571         if (unlikely(rbio->narrow_crcs))
 572                 bch2_rbio_narrow_crcs(rbio);
 573
 574         if (rbio->flags & BCH_READ_NODECODE)
 575                 goto nodecode;
 576
 577         /* Adjust crc to point to subset of data we want: */
 578         crc.offset     += rbio->offset_into_extent;
 579         crc.live_size   = bvec_iter_sectors(rbio->bvec_iter);
 580
 581         if (crc_is_compressed(crc)) {
 582                 ret = bch2_encrypt_bio(c, crc.csum_type, nonce, src);
 583                 if (ret)
 584                         goto decrypt_err;
 585
 586                 if (bch2_bio_uncompress(c, src, dst, dst_iter, crc) &&
 587                     !c->opts.no_data_io)
 588                         goto decompression_err;
 589         } else {
 590                 /* don't need to decrypt the entire bio: */
 591                 nonce = nonce_add(nonce, crc.offset << 9);
 592                 bio_advance(src, crc.offset << 9);
 593
 594                 BUG_ON(src->bi_iter.bi_size < dst_iter.bi_size);
 595                 src->bi_iter.bi_size = dst_iter.bi_size;
 596
 597                 ret = bch2_encrypt_bio(c, crc.csum_type, nonce, src);
 598                 if (ret)
 599                         goto decrypt_err;
 600
 601                 if (rbio->bounce) {
 602                         struct bvec_iter src_iter = src->bi_iter;
 603
 604                         bio_copy_data_iter(dst, &dst_iter, src, &src_iter);
 605                 }
 606         }
 607
 608         if (rbio->promote) {
 609                 /*
 610                  * Re encrypt data we decrypted, so it's consistent with
 611                  * rbio->crc:
 612                  */
 613                 ret = bch2_encrypt_bio(c, crc.csum_type, nonce, src);
 614                 if (ret)
 615                         goto decrypt_err;
 616
 617                 promote_start(rbio->promote, rbio);
 618                 rbio->promote = NULL;
 619         }
 620 nodecode:
 621         if (likely(!(rbio->flags & BCH_READ_IN_RETRY))) {
 622                 rbio = bch2_rbio_free(rbio);
 623                 bch2_rbio_done(rbio);
 624         }
 625 out:
 626         memalloc_nofs_restore(nofs_flags);
 627         return;
 628 csum_err:
 629         /*
 630          * Checksum error: if the bio wasn't bounced, we may have been
 631          * reading into buffers owned by userspace (that userspace can
 632          * scribble over) - retry the read, bouncing it this time:
 633          */
 634         if (!rbio->bounce && (rbio->flags & BCH_READ_USER_MAPPED)) {
 635                 rbio->flags |= BCH_READ_MUST_BOUNCE;
 636                 bch2_rbio_error(rbio, READ_RETRY, BLK_STS_IOERR);
 637                 goto out;
 638         }
 639
 640         bch_err_inum_offset_ratelimited(ca,
 641                 rbio->read_pos.inode,
 642                 rbio->read_pos.offset << 9,
 643                 "data checksum error: expected %0llx:%0llx got %0llx:%0llx (type %s)",
 644                 rbio->pick.crc.csum.hi, rbio->pick.crc.csum.lo,
 645                 csum.hi, csum.lo, bch2_csum_types[crc.csum_type]);
 646         bch2_io_error(ca, BCH_MEMBER_ERROR_checksum);
 647         bch2_rbio_error(rbio, READ_RETRY_AVOID, BLK_STS_IOERR);
 648         goto out;
 649 decompression_err:
 650         bch_err_inum_offset_ratelimited(c, rbio->read_pos.inode,
 651                                         rbio->read_pos.offset << 9,
 652                                         "decompression error");
 653         bch2_rbio_error(rbio, READ_ERR, BLK_STS_IOERR);
 654         goto out;
 655 decrypt_err:
 656         bch_err_inum_offset_ratelimited(c, rbio->read_pos.inode,
 657                                         rbio->read_pos.offset << 9,
 658                                         "decrypt error");
 659         bch2_rbio_error(rbio, READ_ERR, BLK_STS_IOERR);
 660         goto out;
 661 }
 662
 663 static void bch2_read_endio(struct bio *bio)
 664 {
 665         struct bch_read_bio *rbio =
 666                 container_of(bio, struct bch_read_bio, bio);
 667         struct bch_fs *c        = rbio->c;
 668         struct bch_dev *ca      = bch_dev_bkey_exists(c, rbio->pick.ptr.dev);
 669         struct workqueue_struct *wq = NULL;
 670         enum rbio_context context = RBIO_CONTEXT_NULL;
 671
 672         if (rbio->have_ioref) {
 673                 bch2_latency_acct(ca, rbio->submit_time, READ);
 674                 percpu_ref_put(&ca->io_ref);
 675         }
 676
 677         if (!rbio->split)
 678                 rbio->bio.bi_end_io = rbio->end_io;
 679
 680         if (bch2_dev_inum_io_err_on(bio->bi_status, ca, BCH_MEMBER_ERROR_read,
 681                                     rbio->read_pos.inode,
 682                                     rbio->read_pos.offset,
 683                                     "data read error: %s",
 684                                bch2_blk_status_to_str(bio->bi_status))) {
 685                 bch2_rbio_error(rbio, READ_RETRY_AVOID, bio->bi_status);
 686                 return;
 687         }
 688
 689         if (((rbio->flags & BCH_READ_RETRY_IF_STALE) && race_fault()) ||
 690             ptr_stale(ca, &rbio->pick.ptr)) {
 691                 trace_and_count(c, read_reuse_race, &rbio->bio);
 692
 693                 if (rbio->flags & BCH_READ_RETRY_IF_STALE)
 694                         bch2_rbio_error(rbio, READ_RETRY, BLK_STS_AGAIN);
 695                 else
 696                         bch2_rbio_error(rbio, READ_ERR, BLK_STS_AGAIN);
 697                 return;
 698         }
 699
 700         if (rbio->narrow_crcs ||
 701             rbio->promote ||
 702             crc_is_compressed(rbio->pick.crc) ||
 703             bch2_csum_type_is_encryption(rbio->pick.crc.csum_type))
 704                 context = RBIO_CONTEXT_UNBOUND, wq = system_unbound_wq;
 705         else if (rbio->pick.crc.csum_type)
 706                 context = RBIO_CONTEXT_HIGHPRI, wq = system_highpri_wq;
 707
 708         bch2_rbio_punt(rbio, __bch2_read_endio, context, wq);
 709 }
 710
 711 int __bch2_read_indirect_extent(struct btree_trans *trans,
 712                                 unsigned *offset_into_extent,
 713                                 struct bkey_buf *orig_k)
 714 {
 715         struct btree_iter iter;
 716         struct bkey_s_c k;
 717         u64 reflink_offset;
 718         int ret;
 719
 720         reflink_offset = le64_to_cpu(bkey_i_to_reflink_p(orig_k->k)->v.idx) +
 721                 *offset_into_extent;
 722
 723         k = bch2_bkey_get_iter(trans, &iter, BTREE_ID_reflink,
 724                                POS(0, reflink_offset), 0);
 725         ret = bkey_err(k);
 726         if (ret)
 727                 goto err;
 728
 729         if (k.k->type != KEY_TYPE_reflink_v &&
 730             k.k->type != KEY_TYPE_indirect_inline_data) {
 731                 bch_err_inum_offset_ratelimited(trans->c,
 732                         orig_k->k->k.p.inode,
 733                         orig_k->k->k.p.offset << 9,
 734                         "%llu len %u points to nonexistent indirect extent %llu",
 735                         orig_k->k->k.p.offset,
 736                         orig_k->k->k.size,
 737                         reflink_offset);
 738                 bch2_inconsistent_error(trans->c);
 739                 ret = -EIO;
 740                 goto err;
 741         }
 742
 743         *offset_into_extent = iter.pos.offset - bkey_start_offset(k.k);
 744         bch2_bkey_buf_reassemble(orig_k, trans->c, k);
 745 err:
 746         bch2_trans_iter_exit(trans, &iter);
 747         return ret;
 748 }
 749
 750 static noinline void read_from_stale_dirty_pointer(struct btree_trans *trans,
 751                                                    struct bkey_s_c k,
 752                                                    struct bch_extent_ptr ptr)
 753 {
 754         struct bch_fs *c = trans->c;
 755         struct bch_dev *ca = bch_dev_bkey_exists(c, ptr.dev);
 756         struct btree_iter iter;
 757         struct printbuf buf = PRINTBUF;
 758         int ret;
 759
 760         bch2_trans_iter_init(trans, &iter, BTREE_ID_alloc,
 761                              PTR_BUCKET_POS(c, &ptr),
 762                              BTREE_ITER_CACHED);
 763
 764         prt_printf(&buf, "Attempting to read from stale dirty pointer:");
 765         printbuf_indent_add(&buf, 2);
 766         prt_newline(&buf);
 767
 768         bch2_bkey_val_to_text(&buf, c, k);
 769         prt_newline(&buf);
 770
 771         prt_printf(&buf, "memory gen: %u", *bucket_gen(ca, iter.pos.offset));
 772
 773         ret = lockrestart_do(trans, bkey_err(k = bch2_btree_iter_peek_slot(&iter)));
 774         if (!ret) {
 775                 prt_newline(&buf);
 776                 bch2_bkey_val_to_text(&buf, c, k);
 777         }
 778
 779         bch2_fs_inconsistent(c, "%s", buf.buf);
 780
 781         bch2_trans_iter_exit(trans, &iter);
 782         printbuf_exit(&buf);
 783 }
 784
 785 int __bch2_read_extent(struct btree_trans *trans, struct bch_read_bio *orig,
 786                        struct bvec_iter iter, struct bpos read_pos,
 787                        enum btree_id data_btree, struct bkey_s_c k,
 788                        unsigned offset_into_extent,
 789                        struct bch_io_failures *failed, unsigned flags)
 790 {
 791         struct bch_fs *c = trans->c;
 792         struct extent_ptr_decoded pick;
 793         struct bch_read_bio *rbio = NULL;
 794         struct bch_dev *ca = NULL;
 795         struct promote_op *promote = NULL;
 796         bool bounce = false, read_full = false, narrow_crcs = false;
 797         struct bpos data_pos = bkey_start_pos(k.k);
 798         int pick_ret;
 799
 800         if (bkey_extent_is_inline_data(k.k)) {
 801                 unsigned bytes = min_t(unsigned, iter.bi_size,
 802                                        bkey_inline_data_bytes(k.k));
 803
 804                 swap(iter.bi_size, bytes);
 805                 memcpy_to_bio(&orig->bio, iter, bkey_inline_data_p(k));
 806                 swap(iter.bi_size, bytes);
 807                 bio_advance_iter(&orig->bio, &iter, bytes);
 808                 zero_fill_bio_iter(&orig->bio, iter);
 809                 goto out_read_done;
 810         }
 811 retry_pick:
 812         pick_ret = bch2_bkey_pick_read_device(c, k, failed, &pick);
 813
 814         /* hole or reservation - just zero fill: */
 815         if (!pick_ret)
 816                 goto hole;
 817
 818         if (pick_ret < 0) {
 819                 bch_err_inum_offset_ratelimited(c,
 820                                 read_pos.inode, read_pos.offset << 9,
 821                                 "no device to read from");
 822                 goto err;
 823         }
 824
 825         ca = bch_dev_bkey_exists(c, pick.ptr.dev);
 826
 827         /*
 828          * Stale dirty pointers are treated as IO errors, but @failed isn't
 829          * allocated unless we're in the retry path - so if we're not in the
 830          * retry path, don't check here, it'll be caught in bch2_read_endio()
 831          * and we'll end up in the retry path:
 832          */
 833         if ((flags & BCH_READ_IN_RETRY) &&
 834             !pick.ptr.cached &&
 835             unlikely(ptr_stale(ca, &pick.ptr))) {
 836                 read_from_stale_dirty_pointer(trans, k, pick.ptr);
 837                 bch2_mark_io_failure(failed, &pick);
 838                 goto retry_pick;
 839         }
 840
 841         /*
 842          * Unlock the iterator while the btree node's lock is still in
 843          * cache, before doing the IO:
 844          */
 845         bch2_trans_unlock(trans);
 846
 847         if (flags & BCH_READ_NODECODE) {
 848                 /*
 849                  * can happen if we retry, and the extent we were going to read
 850                  * has been merged in the meantime:
 851                  */
 852                 if (pick.crc.compressed_size > orig->bio.bi_vcnt * PAGE_SECTORS)
 853                         goto hole;
 854
 855                 iter.bi_size    = pick.crc.compressed_size << 9;
 856                 goto get_bio;
 857         }
 858
 859         if (!(flags & BCH_READ_LAST_FRAGMENT) ||
 860             bio_flagged(&orig->bio, BIO_CHAIN))
 861                 flags |= BCH_READ_MUST_CLONE;
 862
 863         narrow_crcs = !(flags & BCH_READ_IN_RETRY) &&
 864                 bch2_can_narrow_extent_crcs(k, pick.crc);
 865
 866         if (narrow_crcs && (flags & BCH_READ_USER_MAPPED))
 867                 flags |= BCH_READ_MUST_BOUNCE;
 868
 869         EBUG_ON(offset_into_extent + bvec_iter_sectors(iter) > k.k->size);
 870
 871         if (crc_is_compressed(pick.crc) ||
 872             (pick.crc.csum_type != BCH_CSUM_none &&
 873              (bvec_iter_sectors(iter) != pick.crc.uncompressed_size ||
 874               (bch2_csum_type_is_encryption(pick.crc.csum_type) &&
 875                (flags & BCH_READ_USER_MAPPED)) ||
 876               (flags & BCH_READ_MUST_BOUNCE)))) {
 877                 read_full = true;
 878                 bounce = true;
 879         }
 880
 881         if (orig->opts.promote_target)
 882                 promote = promote_alloc(trans, iter, k, &pick, orig->opts, flags,
 883                                         &rbio, &bounce, &read_full);
 884
 885         if (!read_full) {
 886                 EBUG_ON(crc_is_compressed(pick.crc));
 887                 EBUG_ON(pick.crc.csum_type &&
 888                         (bvec_iter_sectors(iter) != pick.crc.uncompressed_size ||
 889                          bvec_iter_sectors(iter) != pick.crc.live_size ||
 890                          pick.crc.offset ||
 891                          offset_into_extent));
 892
 893                 data_pos.offset += offset_into_extent;
 894                 pick.ptr.offset += pick.crc.offset +
 895                         offset_into_extent;
 896                 offset_into_extent              = 0;
 897                 pick.crc.compressed_size        = bvec_iter_sectors(iter);
 898                 pick.crc.uncompressed_size      = bvec_iter_sectors(iter);
 899                 pick.crc.offset                 = 0;
 900                 pick.crc.live_size              = bvec_iter_sectors(iter);
 901         }
 902 get_bio:
 903         if (rbio) {
 904                 /*
 905                  * promote already allocated bounce rbio:
 906                  * promote needs to allocate a bio big enough for uncompressing
 907                  * data in the write path, but we're not going to use it all
 908                  * here:
 909                  */
 910                 EBUG_ON(rbio->bio.bi_iter.bi_size <
 911                        pick.crc.compressed_size << 9);
 912                 rbio->bio.bi_iter.bi_size =
 913                         pick.crc.compressed_size << 9;
 914         } else if (bounce) {
 915                 unsigned sectors = pick.crc.compressed_size;
 916
 917                 rbio = rbio_init(bio_alloc_bioset(NULL,
 918                                                   DIV_ROUND_UP(sectors, PAGE_SECTORS),
 919                                                   0,
 920                                                   GFP_NOFS,
 921                                                   &c->bio_read_split),
 922                                  orig->opts);
 923
 924                 bch2_bio_alloc_pages_pool(c, &rbio->bio, sectors << 9);
 925                 rbio->bounce    = true;
 926                 rbio->split     = true;
 927         } else if (flags & BCH_READ_MUST_CLONE) {
 928                 /*
 929                  * Have to clone if there were any splits, due to error
 930                  * reporting issues (if a split errored, and retrying didn't
 931                  * work, when it reports the error to its parent (us) we don't
 932                  * know if the error was from our bio, and we should retry, or
 933                  * from the whole bio, in which case we don't want to retry and
 934                  * lose the error)
 935                  */
 936                 rbio = rbio_init(bio_alloc_clone(NULL, &orig->bio, GFP_NOFS,
 937                                                  &c->bio_read_split),
 938                                  orig->opts);
 939                 rbio->bio.bi_iter = iter;
 940                 rbio->split     = true;
 941         } else {
 942                 rbio = orig;
 943                 rbio->bio.bi_iter = iter;
 944                 EBUG_ON(bio_flagged(&rbio->bio, BIO_CHAIN));
 945         }
 946
 947         EBUG_ON(bio_sectors(&rbio->bio) != pick.crc.compressed_size);
 948
 949         rbio->c                 = c;
 950         rbio->submit_time       = local_clock();
 951         if (rbio->split)
 952                 rbio->parent    = orig;
 953         else
 954                 rbio->end_io    = orig->bio.bi_end_io;
 955         rbio->bvec_iter         = iter;
 956         rbio->offset_into_extent= offset_into_extent;
 957         rbio->flags             = flags;
 958         rbio->have_ioref        = pick_ret > 0 && bch2_dev_get_ioref(ca, READ);
 959         rbio->narrow_crcs       = narrow_crcs;
 960         rbio->hole              = 0;
 961         rbio->retry             = 0;
 962         rbio->context           = 0;
 963         /* XXX: only initialize this if needed */
 964         rbio->devs_have         = bch2_bkey_devs(k);
 965         rbio->pick              = pick;
 966         rbio->subvol            = orig->subvol;
 967         rbio->read_pos          = read_pos;
 968         rbio->data_btree        = data_btree;
 969         rbio->data_pos          = data_pos;
 970         rbio->version           = k.k->version;
 971         rbio->promote           = promote;
 972         INIT_WORK(&rbio->work, NULL);
 973
 974         rbio->bio.bi_opf        = orig->bio.bi_opf;
 975         rbio->bio.bi_iter.bi_sector = pick.ptr.offset;
 976         rbio->bio.bi_end_io     = bch2_read_endio;
 977
 978         if (rbio->bounce)
 979                 trace_and_count(c, read_bounce, &rbio->bio);
 980
 981         this_cpu_add(c->counters[BCH_COUNTER_io_read], bio_sectors(&rbio->bio));
 982         bch2_increment_clock(c, bio_sectors(&rbio->bio), READ);
 983
 984         /*
 985          * If it's being moved internally, we don't want to flag it as a cache
 986          * hit:
 987          */
 988         if (pick.ptr.cached && !(flags & BCH_READ_NODECODE))
 989                 bch2_bucket_io_time_reset(trans, pick.ptr.dev,
 990                         PTR_BUCKET_NR(ca, &pick.ptr), READ);
 991
 992         if (!(flags & (BCH_READ_IN_RETRY|BCH_READ_LAST_FRAGMENT))) {
 993                 bio_inc_remaining(&orig->bio);
 994                 trace_and_count(c, read_split, &orig->bio);
 995         }
 996
 997         if (!rbio->pick.idx) {
 998                 if (!rbio->have_ioref) {
 999                         bch_err_inum_offset_ratelimited(c,
1000                                         read_pos.inode,
1001                                         read_pos.offset << 9,
1002                                         "no device to read from");
1003                         bch2_rbio_error(rbio, READ_RETRY_AVOID, BLK_STS_IOERR);
1004                         goto out;
1005                 }
1006
1007                 this_cpu_add(ca->io_done->sectors[READ][BCH_DATA_user],
1008                              bio_sectors(&rbio->bio));
1009                 bio_set_dev(&rbio->bio, ca->disk_sb.bdev);
1010
1011                 if (unlikely(c->opts.no_data_io)) {
1012                         if (likely(!(flags & BCH_READ_IN_RETRY)))
1013                                 bio_endio(&rbio->bio);
1014                 } else {
1015                         if (likely(!(flags & BCH_READ_IN_RETRY)))
1016                                 submit_bio(&rbio->bio);
1017                         else
1018                                 submit_bio_wait(&rbio->bio);
1019                 }
1020
1021                 /*
1022                  * We just submitted IO which may block, we expect relock fail
1023                  * events and shouldn't count them:
1024                  */
1025                 trans->notrace_relock_fail = true;
1026         } else {
1027                 /* Attempting reconstruct read: */
1028                 if (bch2_ec_read_extent(trans, rbio)) {
1029                         bch2_rbio_error(rbio, READ_RETRY_AVOID, BLK_STS_IOERR);
1030                         goto out;
1031                 }
1032
1033                 if (likely(!(flags & BCH_READ_IN_RETRY)))
1034                         bio_endio(&rbio->bio);
1035         }
1036 out:
1037         if (likely(!(flags & BCH_READ_IN_RETRY))) {
1038                 return 0;
1039         } else {
1040                 int ret;
1041
1042                 rbio->context = RBIO_CONTEXT_UNBOUND;
1043                 bch2_read_endio(&rbio->bio);
1044
1045                 ret = rbio->retry;
1046                 rbio = bch2_rbio_free(rbio);
1047
1048                 if (ret == READ_RETRY_AVOID) {
1049                         bch2_mark_io_failure(failed, &pick);
1050                         ret = READ_RETRY;
1051                 }
1052
1053                 if (!ret)
1054                         goto out_read_done;
1055
1056                 return ret;
1057         }
1058
1059 err:
1060         if (flags & BCH_READ_IN_RETRY)
1061                 return READ_ERR;
1062
1063         orig->bio.bi_status = BLK_STS_IOERR;
1064         goto out_read_done;
1065
1066 hole:
1067         /*
1068          * won't normally happen in the BCH_READ_NODECODE
1069          * (bch2_move_extent()) path, but if we retry and the extent we wanted
1070          * to read no longer exists we have to signal that:
1071          */
1072         if (flags & BCH_READ_NODECODE)
1073                 orig->hole = true;
1074
1075         zero_fill_bio_iter(&orig->bio, iter);
1076 out_read_done:
1077         if (flags & BCH_READ_LAST_FRAGMENT)
1078                 bch2_rbio_done(orig);
1079         return 0;
1080 }
1081
1082 void __bch2_read(struct bch_fs *c, struct bch_read_bio *rbio,
1083                  struct bvec_iter bvec_iter, subvol_inum inum,
1084                  struct bch_io_failures *failed, unsigned flags)
1085 {
1086         struct btree_trans *trans = bch2_trans_get(c);
1087         struct btree_iter iter;
1088         struct bkey_buf sk;
1089         struct bkey_s_c k;
1090         u32 snapshot;
1091         int ret;
1092
1093         BUG_ON(flags & BCH_READ_NODECODE);
1094
1095         bch2_bkey_buf_init(&sk);
1096 retry:
1097         bch2_trans_begin(trans);
1098         iter = (struct btree_iter) { NULL };
1099
1100         ret = bch2_subvolume_get_snapshot(trans, inum.subvol, &snapshot);
1101         if (ret)
1102                 goto err;
1103
1104         bch2_trans_iter_init(trans, &iter, BTREE_ID_extents,
1105                              SPOS(inum.inum, bvec_iter.bi_sector, snapshot),
1106                              BTREE_ITER_SLOTS);
1107         while (1) {
1108                 unsigned bytes, sectors, offset_into_extent;
1109                 enum btree_id data_btree = BTREE_ID_extents;
1110
1111                 /*
1112                  * read_extent -> io_time_reset may cause a transaction restart
1113                  * without returning an error, we need to check for that here:
1114                  */
1115                 ret = bch2_trans_relock(trans);
1116                 if (ret)
1117                         break;
1118
1119                 bch2_btree_iter_set_pos(&iter,
1120                                 POS(inum.inum, bvec_iter.bi_sector));
1121
1122                 k = bch2_btree_iter_peek_slot(&iter);
1123                 ret = bkey_err(k);
1124                 if (ret)
1125                         break;
1126
1127                 offset_into_extent = iter.pos.offset -
1128                         bkey_start_offset(k.k);
1129                 sectors = k.k->size - offset_into_extent;
1130
1131                 bch2_bkey_buf_reassemble(&sk, c, k);
1132
1133                 ret = bch2_read_indirect_extent(trans, &data_btree,
1134                                         &offset_into_extent, &sk);
1135                 if (ret)
1136                         break;
1137
1138                 k = bkey_i_to_s_c(sk.k);
1139
1140                 /*
1141                  * With indirect extents, the amount of data to read is the min
1142                  * of the original extent and the indirect extent:
1143                  */
1144                 sectors = min(sectors, k.k->size - offset_into_extent);
1145
1146                 bytes = min(sectors, bvec_iter_sectors(bvec_iter)) << 9;
1147                 swap(bvec_iter.bi_size, bytes);
1148
1149                 if (bvec_iter.bi_size == bytes)
1150                         flags |= BCH_READ_LAST_FRAGMENT;
1151
1152                 ret = __bch2_read_extent(trans, rbio, bvec_iter, iter.pos,
1153                                          data_btree, k,
1154                                          offset_into_extent, failed, flags);
1155                 if (ret)
1156                         break;
1157
1158                 if (flags & BCH_READ_LAST_FRAGMENT)
1159                         break;
1160
1161                 swap(bvec_iter.bi_size, bytes);
1162                 bio_advance_iter(&rbio->bio, &bvec_iter, bytes);
1163
1164                 ret = btree_trans_too_many_iters(trans);
1165                 if (ret)
1166                         break;
1167         }
1168 err:
1169         bch2_trans_iter_exit(trans, &iter);
1170
1171         if (bch2_err_matches(ret, BCH_ERR_transaction_restart) ||
1172             ret == READ_RETRY ||
1173             ret == READ_RETRY_AVOID)
1174                 goto retry;
1175
1176         bch2_trans_put(trans);
1177         bch2_bkey_buf_exit(&sk, c);
1178
1179         if (ret) {
1180                 bch_err_inum_offset_ratelimited(c, inum.inum,
1181                                                 bvec_iter.bi_sector << 9,
1182                                                 "read error %i from btree lookup", ret);
1183                 rbio->bio.bi_status = BLK_STS_IOERR;
1184                 bch2_rbio_done(rbio);
1185         }
1186 }
1187
1188 void bch2_fs_io_read_exit(struct bch_fs *c)
1189 {
1190         if (c->promote_table.tbl)
1191                 rhashtable_destroy(&c->promote_table);
1192         bioset_exit(&c->bio_read_split);
1193         bioset_exit(&c->bio_read);
1194 }
1195
1196 int bch2_fs_io_read_init(struct bch_fs *c)
1197 {
1198         if (bioset_init(&c->bio_read, 1, offsetof(struct bch_read_bio, bio),
1199                         BIOSET_NEED_BVECS))
1200                 return -BCH_ERR_ENOMEM_bio_read_init;
1201
1202         if (bioset_init(&c->bio_read_split, 1, offsetof(struct bch_read_bio, bio),
1203                         BIOSET_NEED_BVECS))
1204                 return -BCH_ERR_ENOMEM_bio_read_split_init;
1205
1206         if (rhashtable_init(&c->promote_table, &bch_promote_params))
1207                 return -BCH_ERR_ENOMEM_promote_table_init;
1208
1209         return 0;
1210 }