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

   1 // SPDX-License-Identifier: GPL-2.0
   2 #ifndef NO_BCACHEFS_FS
   3
   4 #include "bcachefs.h"
   5 #include "btree_iter.h"
   6 #include "extents.h"
   7 #include "fs-io.h"
   8 #include "fs-io-pagecache.h"
   9 #include "subvolume.h"
  10
  11 #include <linux/pagevec.h>
  12 #include <linux/writeback.h>
  13
  14 int bch2_filemap_get_contig_folios_d(struct address_space *mapping,
  15                                      loff_t start, u64 end,
  16                                      fgf_t fgp_flags, gfp_t gfp,
  17                                      folios *fs)
  18 {
  19         struct folio *f;
  20         u64 pos = start;
  21         int ret = 0;
  22
  23         while (pos < end) {
  24                 if ((u64) pos >= (u64) start + (1ULL << 20))
  25                         fgp_flags &= ~FGP_CREAT;
  26
  27                 ret = darray_make_room_gfp(fs, 1, gfp & GFP_KERNEL);
  28                 if (ret)
  29                         break;
  30
  31                 f = __filemap_get_folio(mapping, pos >> PAGE_SHIFT, fgp_flags, gfp);
  32                 if (IS_ERR_OR_NULL(f))
  33                         break;
  34
  35                 BUG_ON(fs->nr && folio_pos(f) != pos);
  36
  37                 pos = folio_end_pos(f);
  38                 darray_push(fs, f);
  39         }
  40
  41         if (!fs->nr && !ret && (fgp_flags & FGP_CREAT))
  42                 ret = -ENOMEM;
  43
  44         return fs->nr ? 0 : ret;
  45 }
  46
  47 /* pagecache_block must be held */
  48 int bch2_write_invalidate_inode_pages_range(struct address_space *mapping,
  49                                             loff_t start, loff_t end)
  50 {
  51         int ret;
  52
  53         /*
  54          * XXX: the way this is currently implemented, we can spin if a process
  55          * is continually redirtying a specific page
  56          */
  57         do {
  58                 if (!mapping->nrpages)
  59                         return 0;
  60
  61                 ret = filemap_write_and_wait_range(mapping, start, end);
  62                 if (ret)
  63                         break;
  64
  65                 if (!mapping->nrpages)
  66                         return 0;
  67
  68                 ret = invalidate_inode_pages2_range(mapping,
  69                                 start >> PAGE_SHIFT,
  70                                 end >> PAGE_SHIFT);
  71         } while (ret == -EBUSY);
  72
  73         return ret;
  74 }
  75
  76 #if 0
  77 /* Useful for debug tracing: */
  78 static const char * const bch2_folio_sector_states[] = {
  79 #define x(n)    #n,
  80         BCH_FOLIO_SECTOR_STATE()
  81 #undef x
  82         NULL
  83 };
  84 #endif
  85
  86 static inline enum bch_folio_sector_state
  87 folio_sector_dirty(enum bch_folio_sector_state state)
  88 {
  89         switch (state) {
  90         case SECTOR_unallocated:
  91                 return SECTOR_dirty;
  92         case SECTOR_reserved:
  93                 return SECTOR_dirty_reserved;
  94         default:
  95                 return state;
  96         }
  97 }
  98
  99 static inline enum bch_folio_sector_state
 100 folio_sector_undirty(enum bch_folio_sector_state state)
 101 {
 102         switch (state) {
 103         case SECTOR_dirty:
 104                 return SECTOR_unallocated;
 105         case SECTOR_dirty_reserved:
 106                 return SECTOR_reserved;
 107         default:
 108                 return state;
 109         }
 110 }
 111
 112 static inline enum bch_folio_sector_state
 113 folio_sector_reserve(enum bch_folio_sector_state state)
 114 {
 115         switch (state) {
 116         case SECTOR_unallocated:
 117                 return SECTOR_reserved;
 118         case SECTOR_dirty:
 119                 return SECTOR_dirty_reserved;
 120         default:
 121                 return state;
 122         }
 123 }
 124
 125 /* for newly allocated folios: */
 126 struct bch_folio *__bch2_folio_create(struct folio *folio, gfp_t gfp)
 127 {
 128         struct bch_folio *s;
 129
 130         s = kzalloc(sizeof(*s) +
 131                     sizeof(struct bch_folio_sector) *
 132                     folio_sectors(folio), gfp);
 133         if (!s)
 134                 return NULL;
 135
 136         spin_lock_init(&s->lock);
 137         folio_attach_private(folio, s);
 138         return s;
 139 }
 140
 141 struct bch_folio *bch2_folio_create(struct folio *folio, gfp_t gfp)
 142 {
 143         return bch2_folio(folio) ?: __bch2_folio_create(folio, gfp);
 144 }
 145
 146 static unsigned bkey_to_sector_state(struct bkey_s_c k)
 147 {
 148         if (bkey_extent_is_reservation(k))
 149                 return SECTOR_reserved;
 150         if (bkey_extent_is_allocation(k.k))
 151                 return SECTOR_allocated;
 152         return SECTOR_unallocated;
 153 }
 154
 155 static void __bch2_folio_set(struct folio *folio,
 156                              unsigned pg_offset, unsigned pg_len,
 157                              unsigned nr_ptrs, unsigned state)
 158 {
 159         struct bch_folio *s = bch2_folio(folio);
 160         unsigned i, sectors = folio_sectors(folio);
 161
 162         BUG_ON(pg_offset >= sectors);
 163         BUG_ON(pg_offset + pg_len > sectors);
 164
 165         spin_lock(&s->lock);
 166
 167         for (i = pg_offset; i < pg_offset + pg_len; i++) {
 168                 s->s[i].nr_replicas     = nr_ptrs;
 169                 bch2_folio_sector_set(folio, s, i, state);
 170         }
 171
 172         if (i == sectors)
 173                 s->uptodate = true;
 174
 175         spin_unlock(&s->lock);
 176 }
 177
 178 /*
 179  * Initialize bch_folio state (allocated/unallocated, nr_replicas) from the
 180  * extents btree:
 181  */
 182 int bch2_folio_set(struct bch_fs *c, subvol_inum inum,
 183                    struct folio **fs, unsigned nr_folios)
 184 {
 185         struct btree_trans *trans;
 186         struct btree_iter iter;
 187         struct bkey_s_c k;
 188         struct bch_folio *s;
 189         u64 offset = folio_sector(fs[0]);
 190         unsigned folio_idx;
 191         u32 snapshot;
 192         bool need_set = false;
 193         int ret;
 194
 195         for (folio_idx = 0; folio_idx < nr_folios; folio_idx++) {
 196                 s = bch2_folio_create(fs[folio_idx], GFP_KERNEL);
 197                 if (!s)
 198                         return -ENOMEM;
 199
 200                 need_set |= !s->uptodate;
 201         }
 202
 203         if (!need_set)
 204                 return 0;
 205
 206         folio_idx = 0;
 207         trans = bch2_trans_get(c);
 208 retry:
 209         bch2_trans_begin(trans);
 210
 211         ret = bch2_subvolume_get_snapshot(trans, inum.subvol, &snapshot);
 212         if (ret)
 213                 goto err;
 214
 215         for_each_btree_key_norestart(trans, iter, BTREE_ID_extents,
 216                            SPOS(inum.inum, offset, snapshot),
 217                            BTREE_ITER_SLOTS, k, ret) {
 218                 unsigned nr_ptrs = bch2_bkey_nr_ptrs_fully_allocated(k);
 219                 unsigned state = bkey_to_sector_state(k);
 220
 221                 while (folio_idx < nr_folios) {
 222                         struct folio *folio = fs[folio_idx];
 223                         u64 folio_start = folio_sector(folio);
 224                         u64 folio_end   = folio_end_sector(folio);
 225                         unsigned folio_offset = max(bkey_start_offset(k.k), folio_start) -
 226                                 folio_start;
 227                         unsigned folio_len = min(k.k->p.offset, folio_end) -
 228                                 folio_offset - folio_start;
 229
 230                         BUG_ON(k.k->p.offset < folio_start);
 231                         BUG_ON(bkey_start_offset(k.k) > folio_end);
 232
 233                         if (!bch2_folio(folio)->uptodate)
 234                                 __bch2_folio_set(folio, folio_offset, folio_len, nr_ptrs, state);
 235
 236                         if (k.k->p.offset < folio_end)
 237                                 break;
 238                         folio_idx++;
 239                 }
 240
 241                 if (folio_idx == nr_folios)
 242                         break;
 243         }
 244
 245         offset = iter.pos.offset;
 246         bch2_trans_iter_exit(trans, &iter);
 247 err:
 248         if (bch2_err_matches(ret, BCH_ERR_transaction_restart))
 249                 goto retry;
 250         bch2_trans_put(trans);
 251
 252         return ret;
 253 }
 254
 255 void bch2_bio_page_state_set(struct bio *bio, struct bkey_s_c k)
 256 {
 257         struct bvec_iter iter;
 258         struct folio_vec fv;
 259         unsigned nr_ptrs = k.k->type == KEY_TYPE_reflink_v
 260                 ? 0 : bch2_bkey_nr_ptrs_fully_allocated(k);
 261         unsigned state = bkey_to_sector_state(k);
 262
 263         bio_for_each_folio(fv, bio, iter)
 264                 __bch2_folio_set(fv.fv_folio,
 265                                  fv.fv_offset >> 9,
 266                                  fv.fv_len >> 9,
 267                                  nr_ptrs, state);
 268 }
 269
 270 void bch2_mark_pagecache_unallocated(struct bch_inode_info *inode,
 271                                      u64 start, u64 end)
 272 {
 273         pgoff_t index = start >> PAGE_SECTORS_SHIFT;
 274         pgoff_t end_index = (end - 1) >> PAGE_SECTORS_SHIFT;
 275         struct folio_batch fbatch;
 276         unsigned i, j;
 277
 278         if (end <= start)
 279                 return;
 280
 281         folio_batch_init(&fbatch);
 282
 283         while (filemap_get_folios(inode->v.i_mapping,
 284                                   &index, end_index, &fbatch)) {
 285                 for (i = 0; i < folio_batch_count(&fbatch); i++) {
 286                         struct folio *folio = fbatch.folios[i];
 287                         u64 folio_start = folio_sector(folio);
 288                         u64 folio_end = folio_end_sector(folio);
 289                         unsigned folio_offset = max(start, folio_start) - folio_start;
 290                         unsigned folio_len = min(end, folio_end) - folio_offset - folio_start;
 291                         struct bch_folio *s;
 292
 293                         BUG_ON(end <= folio_start);
 294
 295                         folio_lock(folio);
 296                         s = bch2_folio(folio);
 297
 298                         if (s) {
 299                                 spin_lock(&s->lock);
 300                                 for (j = folio_offset; j < folio_offset + folio_len; j++)
 301                                         s->s[j].nr_replicas = 0;
 302                                 spin_unlock(&s->lock);
 303                         }
 304
 305                         folio_unlock(folio);
 306                 }
 307                 folio_batch_release(&fbatch);
 308                 cond_resched();
 309         }
 310 }
 311
 312 int bch2_mark_pagecache_reserved(struct bch_inode_info *inode,
 313                                  u64 *start, u64 end,
 314                                  bool nonblocking)
 315 {
 316         struct bch_fs *c = inode->v.i_sb->s_fs_info;
 317         pgoff_t index = *start >> PAGE_SECTORS_SHIFT;
 318         pgoff_t end_index = (end - 1) >> PAGE_SECTORS_SHIFT;
 319         struct folio_batch fbatch;
 320         s64 i_sectors_delta = 0;
 321         int ret = 0;
 322
 323         if (end <= *start)
 324                 return 0;
 325
 326         folio_batch_init(&fbatch);
 327
 328         while (filemap_get_folios(inode->v.i_mapping,
 329                                   &index, end_index, &fbatch)) {
 330                 for (unsigned i = 0; i < folio_batch_count(&fbatch); i++) {
 331                         struct folio *folio = fbatch.folios[i];
 332
 333                         if (!nonblocking)
 334                                 folio_lock(folio);
 335                         else if (!folio_trylock(folio)) {
 336                                 folio_batch_release(&fbatch);
 337                                 ret = -EAGAIN;
 338                                 break;
 339                         }
 340
 341                         u64 folio_start = folio_sector(folio);
 342                         u64 folio_end = folio_end_sector(folio);
 343
 344                         BUG_ON(end <= folio_start);
 345
 346                         *start = min(end, folio_end);
 347
 348                         struct bch_folio *s = bch2_folio(folio);
 349                         if (s) {
 350                                 unsigned folio_offset = max(*start, folio_start) - folio_start;
 351                                 unsigned folio_len = min(end, folio_end) - folio_offset - folio_start;
 352
 353                                 spin_lock(&s->lock);
 354                                 for (unsigned j = folio_offset; j < folio_offset + folio_len; j++) {
 355                                         i_sectors_delta -= s->s[j].state == SECTOR_dirty;
 356                                         bch2_folio_sector_set(folio, s, j,
 357                                                 folio_sector_reserve(s->s[j].state));
 358                                 }
 359                                 spin_unlock(&s->lock);
 360                         }
 361
 362                         folio_unlock(folio);
 363                 }
 364                 folio_batch_release(&fbatch);
 365                 cond_resched();
 366         }
 367
 368         bch2_i_sectors_acct(c, inode, NULL, i_sectors_delta);
 369         return ret;
 370 }
 371
 372 static inline unsigned sectors_to_reserve(struct bch_folio_sector *s,
 373                                           unsigned nr_replicas)
 374 {
 375         return max(0, (int) nr_replicas -
 376                    s->nr_replicas -
 377                    s->replicas_reserved);
 378 }
 379
 380 int bch2_get_folio_disk_reservation(struct bch_fs *c,
 381                                 struct bch_inode_info *inode,
 382                                 struct folio *folio, bool check_enospc)
 383 {
 384         struct bch_folio *s = bch2_folio_create(folio, 0);
 385         unsigned nr_replicas = inode_nr_replicas(c, inode);
 386         struct disk_reservation disk_res = { 0 };
 387         unsigned i, sectors = folio_sectors(folio), disk_res_sectors = 0;
 388         int ret;
 389
 390         if (!s)
 391                 return -ENOMEM;
 392
 393         for (i = 0; i < sectors; i++)
 394                 disk_res_sectors += sectors_to_reserve(&s->s[i], nr_replicas);
 395
 396         if (!disk_res_sectors)
 397                 return 0;
 398
 399         ret = bch2_disk_reservation_get(c, &disk_res,
 400                                         disk_res_sectors, 1,
 401                                         !check_enospc
 402                                         ? BCH_DISK_RESERVATION_NOFAIL
 403                                         : 0);
 404         if (unlikely(ret))
 405                 return ret;
 406
 407         for (i = 0; i < sectors; i++)
 408                 s->s[i].replicas_reserved +=
 409                         sectors_to_reserve(&s->s[i], nr_replicas);
 410
 411         return 0;
 412 }
 413
 414 void bch2_folio_reservation_put(struct bch_fs *c,
 415                         struct bch_inode_info *inode,
 416                         struct bch2_folio_reservation *res)
 417 {
 418         bch2_disk_reservation_put(c, &res->disk);
 419         bch2_quota_reservation_put(c, inode, &res->quota);
 420 }
 421
 422 int bch2_folio_reservation_get(struct bch_fs *c,
 423                         struct bch_inode_info *inode,
 424                         struct folio *folio,
 425                         struct bch2_folio_reservation *res,
 426                         unsigned offset, unsigned len)
 427 {
 428         struct bch_folio *s = bch2_folio_create(folio, 0);
 429         unsigned i, disk_sectors = 0, quota_sectors = 0;
 430         int ret;
 431
 432         if (!s)
 433                 return -ENOMEM;
 434
 435         BUG_ON(!s->uptodate);
 436
 437         for (i = round_down(offset, block_bytes(c)) >> 9;
 438              i < round_up(offset + len, block_bytes(c)) >> 9;
 439              i++) {
 440                 disk_sectors += sectors_to_reserve(&s->s[i],
 441                                                 res->disk.nr_replicas);
 442                 quota_sectors += s->s[i].state == SECTOR_unallocated;
 443         }
 444
 445         if (disk_sectors) {
 446                 ret = bch2_disk_reservation_add(c, &res->disk, disk_sectors, 0);
 447                 if (unlikely(ret))
 448                         return ret;
 449         }
 450
 451         if (quota_sectors) {
 452                 ret = bch2_quota_reservation_add(c, inode, &res->quota,
 453                                                  quota_sectors, true);
 454                 if (unlikely(ret)) {
 455                         struct disk_reservation tmp = {
 456                                 .sectors = disk_sectors
 457                         };
 458
 459                         bch2_disk_reservation_put(c, &tmp);
 460                         res->disk.sectors -= disk_sectors;
 461                         return ret;
 462                 }
 463         }
 464
 465         return 0;
 466 }
 467
 468 static void bch2_clear_folio_bits(struct folio *folio)
 469 {
 470         struct bch_inode_info *inode = to_bch_ei(folio->mapping->host);
 471         struct bch_fs *c = inode->v.i_sb->s_fs_info;
 472         struct bch_folio *s = bch2_folio(folio);
 473         struct disk_reservation disk_res = { 0 };
 474         int i, sectors = folio_sectors(folio), dirty_sectors = 0;
 475
 476         if (!s)
 477                 return;
 478
 479         EBUG_ON(!folio_test_locked(folio));
 480         EBUG_ON(folio_test_writeback(folio));
 481
 482         for (i = 0; i < sectors; i++) {
 483                 disk_res.sectors += s->s[i].replicas_reserved;
 484                 s->s[i].replicas_reserved = 0;
 485
 486                 dirty_sectors -= s->s[i].state == SECTOR_dirty;
 487                 bch2_folio_sector_set(folio, s, i, folio_sector_undirty(s->s[i].state));
 488         }
 489
 490         bch2_disk_reservation_put(c, &disk_res);
 491
 492         bch2_i_sectors_acct(c, inode, NULL, dirty_sectors);
 493
 494         bch2_folio_release(folio);
 495 }
 496
 497 void bch2_set_folio_dirty(struct bch_fs *c,
 498                           struct bch_inode_info *inode,
 499                           struct folio *folio,
 500                           struct bch2_folio_reservation *res,
 501                           unsigned offset, unsigned len)
 502 {
 503         struct bch_folio *s = bch2_folio(folio);
 504         unsigned i, dirty_sectors = 0;
 505
 506         WARN_ON((u64) folio_pos(folio) + offset + len >
 507                 round_up((u64) i_size_read(&inode->v), block_bytes(c)));
 508
 509         BUG_ON(!s->uptodate);
 510
 511         spin_lock(&s->lock);
 512
 513         for (i = round_down(offset, block_bytes(c)) >> 9;
 514              i < round_up(offset + len, block_bytes(c)) >> 9;
 515              i++) {
 516                 unsigned sectors = sectors_to_reserve(&s->s[i],
 517                                                 res->disk.nr_replicas);
 518
 519                 /*
 520                  * This can happen if we race with the error path in
 521                  * bch2_writepage_io_done():
 522                  */
 523                 sectors = min_t(unsigned, sectors, res->disk.sectors);
 524
 525                 s->s[i].replicas_reserved += sectors;
 526                 res->disk.sectors -= sectors;
 527
 528                 dirty_sectors += s->s[i].state == SECTOR_unallocated;
 529
 530                 bch2_folio_sector_set(folio, s, i, folio_sector_dirty(s->s[i].state));
 531         }
 532
 533         spin_unlock(&s->lock);
 534
 535         bch2_i_sectors_acct(c, inode, &res->quota, dirty_sectors);
 536
 537         if (!folio_test_dirty(folio))
 538                 filemap_dirty_folio(inode->v.i_mapping, folio);
 539 }
 540
 541 vm_fault_t bch2_page_fault(struct vm_fault *vmf)
 542 {
 543         struct file *file = vmf->vma->vm_file;
 544         struct address_space *mapping = file->f_mapping;
 545         struct address_space *fdm = faults_disabled_mapping();
 546         struct bch_inode_info *inode = file_bch_inode(file);
 547         vm_fault_t ret;
 548
 549         if (fdm == mapping)
 550                 return VM_FAULT_SIGBUS;
 551
 552         /* Lock ordering: */
 553         if (fdm > mapping) {
 554                 struct bch_inode_info *fdm_host = to_bch_ei(fdm->host);
 555
 556                 if (bch2_pagecache_add_tryget(inode))
 557                         goto got_lock;
 558
 559                 bch2_pagecache_block_put(fdm_host);
 560
 561                 bch2_pagecache_add_get(inode);
 562                 bch2_pagecache_add_put(inode);
 563
 564                 bch2_pagecache_block_get(fdm_host);
 565
 566                 /* Signal that lock has been dropped: */
 567                 set_fdm_dropped_locks();
 568                 return VM_FAULT_SIGBUS;
 569         }
 570
 571         bch2_pagecache_add_get(inode);
 572 got_lock:
 573         ret = filemap_fault(vmf);
 574         bch2_pagecache_add_put(inode);
 575
 576         return ret;
 577 }
 578
 579 vm_fault_t bch2_page_mkwrite(struct vm_fault *vmf)
 580 {
 581         struct folio *folio = page_folio(vmf->page);
 582         struct file *file = vmf->vma->vm_file;
 583         struct bch_inode_info *inode = file_bch_inode(file);
 584         struct address_space *mapping = file->f_mapping;
 585         struct bch_fs *c = inode->v.i_sb->s_fs_info;
 586         struct bch2_folio_reservation res;
 587         unsigned len;
 588         loff_t isize;
 589         vm_fault_t ret;
 590
 591         bch2_folio_reservation_init(c, inode, &res);
 592
 593         sb_start_pagefault(inode->v.i_sb);
 594         file_update_time(file);
 595
 596         /*
 597          * Not strictly necessary, but helps avoid dio writes livelocking in
 598          * bch2_write_invalidate_inode_pages_range() - can drop this if/when we get
 599          * a bch2_write_invalidate_inode_pages_range() that works without dropping
 600          * page lock before invalidating page
 601          */
 602         bch2_pagecache_add_get(inode);
 603
 604         folio_lock(folio);
 605         isize = i_size_read(&inode->v);
 606
 607         if (folio->mapping != mapping || folio_pos(folio) >= isize) {
 608                 folio_unlock(folio);
 609                 ret = VM_FAULT_NOPAGE;
 610                 goto out;
 611         }
 612
 613         len = min_t(loff_t, folio_size(folio), isize - folio_pos(folio));
 614
 615         if (bch2_folio_set(c, inode_inum(inode), &folio, 1) ?:
 616             bch2_folio_reservation_get(c, inode, folio, &res, 0, len)) {
 617                 folio_unlock(folio);
 618                 ret = VM_FAULT_SIGBUS;
 619                 goto out;
 620         }
 621
 622         bch2_set_folio_dirty(c, inode, folio, &res, 0, len);
 623         bch2_folio_reservation_put(c, inode, &res);
 624
 625         folio_wait_stable(folio);
 626         ret = VM_FAULT_LOCKED;
 627 out:
 628         bch2_pagecache_add_put(inode);
 629         sb_end_pagefault(inode->v.i_sb);
 630
 631         return ret;
 632 }
 633
 634 void bch2_invalidate_folio(struct folio *folio, size_t offset, size_t length)
 635 {
 636         if (offset || length < folio_size(folio))
 637                 return;
 638
 639         bch2_clear_folio_bits(folio);
 640 }
 641
 642 bool bch2_release_folio(struct folio *folio, gfp_t gfp_mask)
 643 {
 644         if (folio_test_dirty(folio) || folio_test_writeback(folio))
 645                 return false;
 646
 647         bch2_clear_folio_bits(folio);
 648         return true;
 649 }
 650
 651 /* fseek: */
 652
 653 static int folio_data_offset(struct folio *folio, loff_t pos,
 654                              unsigned min_replicas)
 655 {
 656         struct bch_folio *s = bch2_folio(folio);
 657         unsigned i, sectors = folio_sectors(folio);
 658
 659         if (s)
 660                 for (i = folio_pos_to_s(folio, pos); i < sectors; i++)
 661                         if (s->s[i].state >= SECTOR_dirty &&
 662                             s->s[i].nr_replicas + s->s[i].replicas_reserved >= min_replicas)
 663                                 return i << SECTOR_SHIFT;
 664
 665         return -1;
 666 }
 667
 668 loff_t bch2_seek_pagecache_data(struct inode *vinode,
 669                                 loff_t start_offset,
 670                                 loff_t end_offset,
 671                                 unsigned min_replicas,
 672                                 bool nonblock)
 673 {
 674         struct folio_batch fbatch;
 675         pgoff_t start_index     = start_offset >> PAGE_SHIFT;
 676         pgoff_t end_index       = end_offset >> PAGE_SHIFT;
 677         pgoff_t index           = start_index;
 678         unsigned i;
 679         loff_t ret;
 680         int offset;
 681
 682         folio_batch_init(&fbatch);
 683
 684         while (filemap_get_folios(vinode->i_mapping,
 685                                   &index, end_index, &fbatch)) {
 686                 for (i = 0; i < folio_batch_count(&fbatch); i++) {
 687                         struct folio *folio = fbatch.folios[i];
 688
 689                         if (!nonblock) {
 690                                 folio_lock(folio);
 691                         } else if (!folio_trylock(folio)) {
 692                                 folio_batch_release(&fbatch);
 693                                 return -EAGAIN;
 694                         }
 695
 696                         offset = folio_data_offset(folio,
 697                                         max(folio_pos(folio), start_offset),
 698                                         min_replicas);
 699                         if (offset >= 0) {
 700                                 ret = clamp(folio_pos(folio) + offset,
 701                                             start_offset, end_offset);
 702                                 folio_unlock(folio);
 703                                 folio_batch_release(&fbatch);
 704                                 return ret;
 705                         }
 706                         folio_unlock(folio);
 707                 }
 708                 folio_batch_release(&fbatch);
 709                 cond_resched();
 710         }
 711
 712         return end_offset;
 713 }
 714
 715 /*
 716  * Search for a hole in a folio.
 717  *
 718  * The filemap layer returns -ENOENT if no folio exists, so reuse the same error
 719  * code to indicate a pagecache hole exists at the returned offset. Otherwise
 720  * return 0 if the folio is filled with data, or an error code. This function
 721  * can return -EAGAIN if nonblock is specified.
 722  */
 723 static int folio_hole_offset(struct address_space *mapping, loff_t *offset,
 724                               unsigned min_replicas, bool nonblock)
 725 {
 726         struct folio *folio;
 727         struct bch_folio *s;
 728         unsigned i, sectors;
 729         int ret = -ENOENT;
 730
 731         folio = __filemap_get_folio(mapping, *offset >> PAGE_SHIFT,
 732                                     FGP_LOCK|(nonblock ? FGP_NOWAIT : 0), 0);
 733         if (IS_ERR(folio))
 734                 return PTR_ERR(folio);
 735
 736         s = bch2_folio(folio);
 737         if (!s)
 738                 goto unlock;
 739
 740         sectors = folio_sectors(folio);
 741         for (i = folio_pos_to_s(folio, *offset); i < sectors; i++)
 742                 if (s->s[i].state < SECTOR_dirty ||
 743                     s->s[i].nr_replicas + s->s[i].replicas_reserved < min_replicas) {
 744                         *offset = max(*offset,
 745                                       folio_pos(folio) + (i << SECTOR_SHIFT));
 746                         goto unlock;
 747                 }
 748
 749         *offset = folio_end_pos(folio);
 750         ret = 0;
 751 unlock:
 752         folio_unlock(folio);
 753         folio_put(folio);
 754         return ret;
 755 }
 756
 757 loff_t bch2_seek_pagecache_hole(struct inode *vinode,
 758                                 loff_t start_offset,
 759                                 loff_t end_offset,
 760                                 unsigned min_replicas,
 761                                 bool nonblock)
 762 {
 763         struct address_space *mapping = vinode->i_mapping;
 764         loff_t offset = start_offset;
 765         loff_t ret = 0;
 766
 767         while (!ret && offset < end_offset)
 768                 ret = folio_hole_offset(mapping, &offset, min_replicas, nonblock);
 769
 770         if (ret && ret != -ENOENT)
 771                 return ret;
 772         return min(offset, end_offset);
 773 }
 774
 775 int bch2_clamp_data_hole(struct inode *inode,
 776                          u64 *hole_start,
 777                          u64 *hole_end,
 778                          unsigned min_replicas,
 779                          bool nonblock)
 780 {
 781         loff_t ret;
 782
 783         ret = bch2_seek_pagecache_hole(inode,
 784                 *hole_start << 9, *hole_end << 9, min_replicas, nonblock) >> 9;
 785         if (ret < 0)
 786                 return ret;
 787
 788         *hole_start = ret;
 789
 790         if (*hole_start == *hole_end)
 791                 return 0;
 792
 793         ret = bch2_seek_pagecache_data(inode,
 794                 *hole_start << 9, *hole_end << 9, min_replicas, nonblock) >> 9;
 795         if (ret < 0)
 796                 return ret;
 797
 798         *hole_end = ret;
 799         return 0;
 800 }
 801
 802 #endif /* NO_BCACHEFS_FS */