git.sesse.net Git - bcachefs-tools-debian/blob - libbcachefs/fs-io-direct.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 #ifndef NO_BCACHEFS_FS
   3
   4 #include "bcachefs.h"
   5 #include "alloc_foreground.h"
   6 #include "fs.h"
   7 #include "fs-io.h"
   8 #include "fs-io-direct.h"
   9 #include "fs-io-pagecache.h"
  10 #include "io_read.h"
  11 #include "io_write.h"
  12
  13 #include <linux/kthread.h>
  14 #include <linux/pagemap.h>
  15 #include <linux/prefetch.h>
  16 #include <linux/task_io_accounting_ops.h>
  17
  18 /* O_DIRECT reads */
  19
  20 struct dio_read {
  21         struct closure                  cl;
  22         struct kiocb                    *req;
  23         long                            ret;
  24         bool                            should_dirty;
  25         struct bch_read_bio             rbio;
  26 };
  27
  28 static void bio_check_or_release(struct bio *bio, bool check_dirty)
  29 {
  30         if (check_dirty) {
  31                 bio_check_pages_dirty(bio);
  32         } else {
  33                 bio_release_pages(bio, false);
  34                 bio_put(bio);
  35         }
  36 }
  37
  38 static CLOSURE_CALLBACK(bch2_dio_read_complete)
  39 {
  40         closure_type(dio, struct dio_read, cl);
  41
  42         dio->req->ki_complete(dio->req, dio->ret);
  43         bio_check_or_release(&dio->rbio.bio, dio->should_dirty);
  44 }
  45
  46 static void bch2_direct_IO_read_endio(struct bio *bio)
  47 {
  48         struct dio_read *dio = bio->bi_private;
  49
  50         if (bio->bi_status)
  51                 dio->ret = blk_status_to_errno(bio->bi_status);
  52
  53         closure_put(&dio->cl);
  54 }
  55
  56 static void bch2_direct_IO_read_split_endio(struct bio *bio)
  57 {
  58         struct dio_read *dio = bio->bi_private;
  59         bool should_dirty = dio->should_dirty;
  60
  61         bch2_direct_IO_read_endio(bio);
  62         bio_check_or_release(bio, should_dirty);
  63 }
  64
  65 static int bch2_direct_IO_read(struct kiocb *req, struct iov_iter *iter)
  66 {
  67         struct file *file = req->ki_filp;
  68         struct bch_inode_info *inode = file_bch_inode(file);
  69         struct bch_fs *c = inode->v.i_sb->s_fs_info;
  70         struct bch_io_opts opts;
  71         struct dio_read *dio;
  72         struct bio *bio;
  73         loff_t offset = req->ki_pos;
  74         bool sync = is_sync_kiocb(req);
  75         size_t shorten;
  76         ssize_t ret;
  77
  78         bch2_inode_opts_get(&opts, c, &inode->ei_inode);
  79
  80         /* bios must be 512 byte aligned: */
  81         if ((offset|iter->count) & (SECTOR_SIZE - 1))
  82                 return -EINVAL;
  83
  84         ret = min_t(loff_t, iter->count,
  85                     max_t(loff_t, 0, i_size_read(&inode->v) - offset));
  86
  87         if (!ret)
  88                 return ret;
  89
  90         shorten = iov_iter_count(iter) - round_up(ret, block_bytes(c));
  91         if (shorten >= iter->count)
  92                 shorten = 0;
  93         iter->count -= shorten;
  94
  95         bio = bio_alloc_bioset(NULL,
  96                                bio_iov_vecs_to_alloc(iter, BIO_MAX_VECS),
  97                                REQ_OP_READ,
  98                                GFP_KERNEL,
  99                                &c->dio_read_bioset);
 100
 101         bio->bi_end_io = bch2_direct_IO_read_endio;
 102
 103         dio = container_of(bio, struct dio_read, rbio.bio);
 104         closure_init(&dio->cl, NULL);
 105
 106         /*
 107          * this is a _really_ horrible hack just to avoid an atomic sub at the
 108          * end:
 109          */
 110         if (!sync) {
 111                 set_closure_fn(&dio->cl, bch2_dio_read_complete, NULL);
 112                 atomic_set(&dio->cl.remaining,
 113                            CLOSURE_REMAINING_INITIALIZER -
 114                            CLOSURE_RUNNING +
 115                            CLOSURE_DESTRUCTOR);
 116         } else {
 117                 atomic_set(&dio->cl.remaining,
 118                            CLOSURE_REMAINING_INITIALIZER + 1);
 119                 dio->cl.closure_get_happened = true;
 120         }
 121
 122         dio->req        = req;
 123         dio->ret        = ret;
 124         /*
 125          * This is one of the sketchier things I've encountered: we have to skip
 126          * the dirtying of requests that are internal from the kernel (i.e. from
 127          * loopback), because we'll deadlock on page_lock.
 128          */
 129         dio->should_dirty = iter_is_iovec(iter);
 130
 131         goto start;
 132         while (iter->count) {
 133                 bio = bio_alloc_bioset(NULL,
 134                                        bio_iov_vecs_to_alloc(iter, BIO_MAX_VECS),
 135                                        REQ_OP_READ,
 136                                        GFP_KERNEL,
 137                                        &c->bio_read);
 138                 bio->bi_end_io          = bch2_direct_IO_read_split_endio;
 139 start:
 140                 bio->bi_opf             = REQ_OP_READ|REQ_SYNC;
 141                 bio->bi_iter.bi_sector  = offset >> 9;
 142                 bio->bi_private         = dio;
 143
 144                 ret = bio_iov_iter_get_pages(bio, iter);
 145                 if (ret < 0) {
 146                         /* XXX: fault inject this path */
 147                         bio->bi_status = BLK_STS_RESOURCE;
 148                         bio_endio(bio);
 149                         break;
 150                 }
 151
 152                 offset += bio->bi_iter.bi_size;
 153
 154                 if (dio->should_dirty)
 155                         bio_set_pages_dirty(bio);
 156
 157                 if (iter->count)
 158                         closure_get(&dio->cl);
 159
 160                 bch2_read(c, rbio_init(bio, opts), inode_inum(inode));
 161         }
 162
 163         iter->count += shorten;
 164
 165         if (sync) {
 166                 closure_sync(&dio->cl);
 167                 closure_debug_destroy(&dio->cl);
 168                 ret = dio->ret;
 169                 bio_check_or_release(&dio->rbio.bio, dio->should_dirty);
 170                 return ret;
 171         } else {
 172                 return -EIOCBQUEUED;
 173         }
 174 }
 175
 176 ssize_t bch2_read_iter(struct kiocb *iocb, struct iov_iter *iter)
 177 {
 178         struct file *file = iocb->ki_filp;
 179         struct bch_inode_info *inode = file_bch_inode(file);
 180         struct address_space *mapping = file->f_mapping;
 181         size_t count = iov_iter_count(iter);
 182         ssize_t ret;
 183
 184         if (!count)
 185                 return 0; /* skip atime */
 186
 187         if (iocb->ki_flags & IOCB_DIRECT) {
 188                 struct blk_plug plug;
 189
 190                 if (unlikely(mapping->nrpages)) {
 191                         ret = filemap_write_and_wait_range(mapping,
 192                                                 iocb->ki_pos,
 193                                                 iocb->ki_pos + count - 1);
 194                         if (ret < 0)
 195                                 goto out;
 196                 }
 197
 198                 file_accessed(file);
 199
 200                 blk_start_plug(&plug);
 201                 ret = bch2_direct_IO_read(iocb, iter);
 202                 blk_finish_plug(&plug);
 203
 204                 if (ret >= 0)
 205                         iocb->ki_pos += ret;
 206         } else {
 207                 bch2_pagecache_add_get(inode);
 208                 ret = generic_file_read_iter(iocb, iter);
 209                 bch2_pagecache_add_put(inode);
 210         }
 211 out:
 212         return bch2_err_class(ret);
 213 }
 214
 215 /* O_DIRECT writes */
 216
 217 struct dio_write {
 218         struct kiocb                    *req;
 219         struct address_space            *mapping;
 220         struct bch_inode_info           *inode;
 221         struct mm_struct                *mm;
 222         const struct iovec              *iov;
 223         unsigned                        loop:1,
 224                                         extending:1,
 225                                         sync:1,
 226                                         flush:1;
 227         struct quota_res                quota_res;
 228         u64                             written;
 229
 230         struct iov_iter                 iter;
 231         struct iovec                    inline_vecs[2];
 232
 233         /* must be last: */
 234         struct bch_write_op             op;
 235 };
 236
 237 static bool bch2_check_range_allocated(struct bch_fs *c, subvol_inum inum,
 238                                        u64 offset, u64 size,
 239                                        unsigned nr_replicas, bool compressed)
 240 {
 241         struct btree_trans *trans = bch2_trans_get(c);
 242         struct btree_iter iter;
 243         struct bkey_s_c k;
 244         u64 end = offset + size;
 245         u32 snapshot;
 246         bool ret = true;
 247         int err;
 248 retry:
 249         bch2_trans_begin(trans);
 250
 251         err = bch2_subvolume_get_snapshot(trans, inum.subvol, &snapshot);
 252         if (err)
 253                 goto err;
 254
 255         for_each_btree_key_norestart(trans, iter, BTREE_ID_extents,
 256                            SPOS(inum.inum, offset, snapshot),
 257                            BTREE_ITER_SLOTS, k, err) {
 258                 if (bkey_ge(bkey_start_pos(k.k), POS(inum.inum, end)))
 259                         break;
 260
 261                 if (k.k->p.snapshot != snapshot ||
 262                     nr_replicas > bch2_bkey_replicas(c, k) ||
 263                     (!compressed && bch2_bkey_sectors_compressed(k))) {
 264                         ret = false;
 265                         break;
 266                 }
 267         }
 268
 269         offset = iter.pos.offset;
 270         bch2_trans_iter_exit(trans, &iter);
 271 err:
 272         if (bch2_err_matches(err, BCH_ERR_transaction_restart))
 273                 goto retry;
 274         bch2_trans_put(trans);
 275
 276         return err ? false : ret;
 277 }
 278
 279 static noinline bool bch2_dio_write_check_allocated(struct dio_write *dio)
 280 {
 281         struct bch_fs *c = dio->op.c;
 282         struct bch_inode_info *inode = dio->inode;
 283         struct bio *bio = &dio->op.wbio.bio;
 284
 285         return bch2_check_range_allocated(c, inode_inum(inode),
 286                                 dio->op.pos.offset, bio_sectors(bio),
 287                                 dio->op.opts.data_replicas,
 288                                 dio->op.opts.compression != 0);
 289 }
 290
 291 static void bch2_dio_write_loop_async(struct bch_write_op *);
 292 static __always_inline long bch2_dio_write_done(struct dio_write *dio);
 293
 294 /*
 295  * We're going to return -EIOCBQUEUED, but we haven't finished consuming the
 296  * iov_iter yet, so we need to stash a copy of the iovec: it might be on the
 297  * caller's stack, we're not guaranteed that it will live for the duration of
 298  * the IO:
 299  */
 300 static noinline int bch2_dio_write_copy_iov(struct dio_write *dio)
 301 {
 302         struct iovec *iov = dio->inline_vecs;
 303
 304         /*
 305          * iov_iter has a single embedded iovec - nothing to do:
 306          */
 307         if (iter_is_ubuf(&dio->iter))
 308                 return 0;
 309
 310         /*
 311          * We don't currently handle non-iovec iov_iters here - return an error,
 312          * and we'll fall back to doing the IO synchronously:
 313          */
 314         if (!iter_is_iovec(&dio->iter))
 315                 return -1;
 316
 317         if (dio->iter.nr_segs > ARRAY_SIZE(dio->inline_vecs)) {
 318                 dio->iov = iov = kmalloc_array(dio->iter.nr_segs, sizeof(*iov),
 319                                     GFP_KERNEL);
 320                 if (unlikely(!iov))
 321                         return -ENOMEM;
 322         }
 323
 324         memcpy(iov, dio->iter.__iov, dio->iter.nr_segs * sizeof(*iov));
 325         dio->iter.__iov = iov;
 326         return 0;
 327 }
 328
 329 static CLOSURE_CALLBACK(bch2_dio_write_flush_done)
 330 {
 331         closure_type(dio, struct dio_write, op.cl);
 332         struct bch_fs *c = dio->op.c;
 333
 334         closure_debug_destroy(cl);
 335
 336         dio->op.error = bch2_journal_error(&c->journal);
 337
 338         bch2_dio_write_done(dio);
 339 }
 340
 341 static noinline void bch2_dio_write_flush(struct dio_write *dio)
 342 {
 343         struct bch_fs *c = dio->op.c;
 344         struct bch_inode_unpacked inode;
 345         int ret;
 346
 347         dio->flush = 0;
 348
 349         closure_init(&dio->op.cl, NULL);
 350
 351         if (!dio->op.error) {
 352                 ret = bch2_inode_find_by_inum(c, inode_inum(dio->inode), &inode);
 353                 if (ret) {
 354                         dio->op.error = ret;
 355                 } else {
 356                         bch2_journal_flush_seq_async(&c->journal, inode.bi_journal_seq,
 357                                                      &dio->op.cl);
 358                         bch2_inode_flush_nocow_writes_async(c, dio->inode, &dio->op.cl);
 359                 }
 360         }
 361
 362         if (dio->sync) {
 363                 closure_sync(&dio->op.cl);
 364                 closure_debug_destroy(&dio->op.cl);
 365         } else {
 366                 continue_at(&dio->op.cl, bch2_dio_write_flush_done, NULL);
 367         }
 368 }
 369
 370 static __always_inline long bch2_dio_write_done(struct dio_write *dio)
 371 {
 372         struct kiocb *req = dio->req;
 373         struct bch_inode_info *inode = dio->inode;
 374         bool sync = dio->sync;
 375         long ret;
 376
 377         if (unlikely(dio->flush)) {
 378                 bch2_dio_write_flush(dio);
 379                 if (!sync)
 380                         return -EIOCBQUEUED;
 381         }
 382
 383         bch2_pagecache_block_put(inode);
 384
 385         kfree(dio->iov);
 386
 387         ret = dio->op.error ?: ((long) dio->written << 9);
 388         bio_put(&dio->op.wbio.bio);
 389
 390         /* inode->i_dio_count is our ref on inode and thus bch_fs */
 391         inode_dio_end(&inode->v);
 392
 393         if (ret < 0)
 394                 ret = bch2_err_class(ret);
 395
 396         if (!sync) {
 397                 req->ki_complete(req, ret);
 398                 ret = -EIOCBQUEUED;
 399         }
 400         return ret;
 401 }
 402
 403 static __always_inline void bch2_dio_write_end(struct dio_write *dio)
 404 {
 405         struct bch_fs *c = dio->op.c;
 406         struct kiocb *req = dio->req;
 407         struct bch_inode_info *inode = dio->inode;
 408         struct bio *bio = &dio->op.wbio.bio;
 409
 410         req->ki_pos     += (u64) dio->op.written << 9;
 411         dio->written    += dio->op.written;
 412
 413         if (dio->extending) {
 414                 spin_lock(&inode->v.i_lock);
 415                 if (req->ki_pos > inode->v.i_size)
 416                         i_size_write(&inode->v, req->ki_pos);
 417                 spin_unlock(&inode->v.i_lock);
 418         }
 419
 420         if (dio->op.i_sectors_delta || dio->quota_res.sectors) {
 421                 mutex_lock(&inode->ei_quota_lock);
 422                 __bch2_i_sectors_acct(c, inode, &dio->quota_res, dio->op.i_sectors_delta);
 423                 __bch2_quota_reservation_put(c, inode, &dio->quota_res);
 424                 mutex_unlock(&inode->ei_quota_lock);
 425         }
 426
 427         bio_release_pages(bio, false);
 428
 429         if (unlikely(dio->op.error))
 430                 set_bit(EI_INODE_ERROR, &inode->ei_flags);
 431 }
 432
 433 static __always_inline long bch2_dio_write_loop(struct dio_write *dio)
 434 {
 435         struct bch_fs *c = dio->op.c;
 436         struct kiocb *req = dio->req;
 437         struct address_space *mapping = dio->mapping;
 438         struct bch_inode_info *inode = dio->inode;
 439         struct bch_io_opts opts;
 440         struct bio *bio = &dio->op.wbio.bio;
 441         unsigned unaligned, iter_count;
 442         bool sync = dio->sync, dropped_locks;
 443         long ret;
 444
 445         bch2_inode_opts_get(&opts, c, &inode->ei_inode);
 446
 447         while (1) {
 448                 iter_count = dio->iter.count;
 449
 450                 EBUG_ON(current->faults_disabled_mapping);
 451                 current->faults_disabled_mapping = mapping;
 452
 453                 ret = bio_iov_iter_get_pages(bio, &dio->iter);
 454
 455                 dropped_locks = fdm_dropped_locks();
 456
 457                 current->faults_disabled_mapping = NULL;
 458
 459                 /*
 460                  * If the fault handler returned an error but also signalled
 461                  * that it dropped & retook ei_pagecache_lock, we just need to
 462                  * re-shoot down the page cache and retry:
 463                  */
 464                 if (dropped_locks && ret)
 465                         ret = 0;
 466
 467                 if (unlikely(ret < 0))
 468                         goto err;
 469
 470                 if (unlikely(dropped_locks)) {
 471                         ret = bch2_write_invalidate_inode_pages_range(mapping,
 472                                         req->ki_pos,
 473                                         req->ki_pos + iter_count - 1);
 474                         if (unlikely(ret))
 475                                 goto err;
 476
 477                         if (!bio->bi_iter.bi_size)
 478                                 continue;
 479                 }
 480
 481                 unaligned = bio->bi_iter.bi_size & (block_bytes(c) - 1);
 482                 bio->bi_iter.bi_size -= unaligned;
 483                 iov_iter_revert(&dio->iter, unaligned);
 484
 485                 if (!bio->bi_iter.bi_size) {
 486                         /*
 487                          * bio_iov_iter_get_pages was only able to get <
 488                          * blocksize worth of pages:
 489                          */
 490                         ret = -EFAULT;
 491                         goto err;
 492                 }
 493
 494                 bch2_write_op_init(&dio->op, c, opts);
 495                 dio->op.end_io          = sync
 496                         ? NULL
 497                         : bch2_dio_write_loop_async;
 498                 dio->op.target          = dio->op.opts.foreground_target;
 499                 dio->op.write_point     = writepoint_hashed((unsigned long) current);
 500                 dio->op.nr_replicas     = dio->op.opts.data_replicas;
 501                 dio->op.subvol          = inode->ei_subvol;
 502                 dio->op.pos             = POS(inode->v.i_ino, (u64) req->ki_pos >> 9);
 503                 dio->op.devs_need_flush = &inode->ei_devs_need_flush;
 504
 505                 if (sync)
 506                         dio->op.flags |= BCH_WRITE_SYNC;
 507                 dio->op.flags |= BCH_WRITE_CHECK_ENOSPC;
 508
 509                 ret = bch2_quota_reservation_add(c, inode, &dio->quota_res,
 510                                                  bio_sectors(bio), true);
 511                 if (unlikely(ret))
 512                         goto err;
 513
 514                 ret = bch2_disk_reservation_get(c, &dio->op.res, bio_sectors(bio),
 515                                                 dio->op.opts.data_replicas, 0);
 516                 if (unlikely(ret) &&
 517                     !bch2_dio_write_check_allocated(dio))
 518                         goto err;
 519
 520                 task_io_account_write(bio->bi_iter.bi_size);
 521
 522                 if (unlikely(dio->iter.count) &&
 523                     !dio->sync &&
 524                     !dio->loop &&
 525                     bch2_dio_write_copy_iov(dio))
 526                         dio->sync = sync = true;
 527
 528                 dio->loop = true;
 529                 closure_call(&dio->op.cl, bch2_write, NULL, NULL);
 530
 531                 if (!sync)
 532                         return -EIOCBQUEUED;
 533
 534                 bch2_dio_write_end(dio);
 535
 536                 if (likely(!dio->iter.count) || dio->op.error)
 537                         break;
 538
 539                 bio_reset(bio, NULL, REQ_OP_WRITE);
 540         }
 541 out:
 542         return bch2_dio_write_done(dio);
 543 err:
 544         dio->op.error = ret;
 545
 546         bio_release_pages(bio, false);
 547
 548         bch2_quota_reservation_put(c, inode, &dio->quota_res);
 549         goto out;
 550 }
 551
 552 static noinline __cold void bch2_dio_write_continue(struct dio_write *dio)
 553 {
 554         struct mm_struct *mm = dio->mm;
 555
 556         bio_reset(&dio->op.wbio.bio, NULL, REQ_OP_WRITE);
 557
 558         if (mm)
 559                 kthread_use_mm(mm);
 560         bch2_dio_write_loop(dio);
 561         if (mm)
 562                 kthread_unuse_mm(mm);
 563 }
 564
 565 static void bch2_dio_write_loop_async(struct bch_write_op *op)
 566 {
 567         struct dio_write *dio = container_of(op, struct dio_write, op);
 568
 569         bch2_dio_write_end(dio);
 570
 571         if (likely(!dio->iter.count) || dio->op.error)
 572                 bch2_dio_write_done(dio);
 573         else
 574                 bch2_dio_write_continue(dio);
 575 }
 576
 577 ssize_t bch2_direct_write(struct kiocb *req, struct iov_iter *iter)
 578 {
 579         struct file *file = req->ki_filp;
 580         struct address_space *mapping = file->f_mapping;
 581         struct bch_inode_info *inode = file_bch_inode(file);
 582         struct bch_fs *c = inode->v.i_sb->s_fs_info;
 583         struct dio_write *dio;
 584         struct bio *bio;
 585         bool locked = true, extending;
 586         ssize_t ret;
 587
 588         prefetch(&c->opts);
 589         prefetch((void *) &c->opts + 64);
 590         prefetch(&inode->ei_inode);
 591         prefetch((void *) &inode->ei_inode + 64);
 592
 593         inode_lock(&inode->v);
 594
 595         ret = generic_write_checks(req, iter);
 596         if (unlikely(ret <= 0))
 597                 goto err;
 598
 599         ret = file_remove_privs(file);
 600         if (unlikely(ret))
 601                 goto err;
 602
 603         ret = file_update_time(file);
 604         if (unlikely(ret))
 605                 goto err;
 606
 607         if (unlikely((req->ki_pos|iter->count) & (block_bytes(c) - 1)))
 608                 goto err;
 609
 610         inode_dio_begin(&inode->v);
 611         bch2_pagecache_block_get(inode);
 612
 613         extending = req->ki_pos + iter->count > inode->v.i_size;
 614         if (!extending) {
 615                 inode_unlock(&inode->v);
 616                 locked = false;
 617         }
 618
 619         bio = bio_alloc_bioset(NULL,
 620                                bio_iov_vecs_to_alloc(iter, BIO_MAX_VECS),
 621                                REQ_OP_WRITE,
 622                                GFP_KERNEL,
 623                                &c->dio_write_bioset);
 624         dio = container_of(bio, struct dio_write, op.wbio.bio);
 625         dio->req                = req;
 626         dio->mapping            = mapping;
 627         dio->inode              = inode;
 628         dio->mm                 = current->mm;
 629         dio->iov                = NULL;
 630         dio->loop               = false;
 631         dio->extending          = extending;
 632         dio->sync               = is_sync_kiocb(req) || extending;
 633         dio->flush              = iocb_is_dsync(req) && !c->opts.journal_flush_disabled;
 634         dio->quota_res.sectors  = 0;
 635         dio->written            = 0;
 636         dio->iter               = *iter;
 637         dio->op.c               = c;
 638
 639         if (unlikely(mapping->nrpages)) {
 640                 ret = bch2_write_invalidate_inode_pages_range(mapping,
 641                                                 req->ki_pos,
 642                                                 req->ki_pos + iter->count - 1);
 643                 if (unlikely(ret))
 644                         goto err_put_bio;
 645         }
 646
 647         ret = bch2_dio_write_loop(dio);
 648 err:
 649         if (locked)
 650                 inode_unlock(&inode->v);
 651         return ret;
 652 err_put_bio:
 653         bch2_pagecache_block_put(inode);
 654         bio_put(bio);
 655         inode_dio_end(&inode->v);
 656         goto err;
 657 }
 658
 659 void bch2_fs_fs_io_direct_exit(struct bch_fs *c)
 660 {
 661         bioset_exit(&c->dio_write_bioset);
 662         bioset_exit(&c->dio_read_bioset);
 663 }
 664
 665 int bch2_fs_fs_io_direct_init(struct bch_fs *c)
 666 {
 667         if (bioset_init(&c->dio_read_bioset,
 668                         4, offsetof(struct dio_read, rbio.bio),
 669                         BIOSET_NEED_BVECS))
 670                 return -BCH_ERR_ENOMEM_dio_read_bioset_init;
 671
 672         if (bioset_init(&c->dio_write_bioset,
 673                         4, offsetof(struct dio_write, op.wbio.bio),
 674                         BIOSET_NEED_BVECS))
 675                 return -BCH_ERR_ENOMEM_dio_write_bioset_init;
 676
 677         return 0;
 678 }
 679
 680 #endif /* NO_BCACHEFS_FS */