git.sesse.net Git - bcachefs-tools-debian/blob - c_src/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 void bch2_mark_pagecache_reserved(struct bch_inode_info *inode,
 313                                   u64 start, u64 end)
 314 {
 315         struct bch_fs *c = inode->v.i_sb->s_fs_info;
 316         pgoff_t index = start >> PAGE_SECTORS_SHIFT;
 317         pgoff_t end_index = (end - 1) >> PAGE_SECTORS_SHIFT;
 318         struct folio_batch fbatch;
 319         s64 i_sectors_delta = 0;
 320         unsigned i, j;
 321
 322         if (end <= start)
 323                 return;
 324
 325         folio_batch_init(&fbatch);
 326
 327         while (filemap_get_folios(inode->v.i_mapping,
 328                                   &index, end_index, &fbatch)) {
 329                 for (i = 0; i < folio_batch_count(&fbatch); i++) {
 330                         struct folio *folio = fbatch.folios[i];
 331                         u64 folio_start = folio_sector(folio);
 332                         u64 folio_end = folio_end_sector(folio);
 333                         unsigned folio_offset = max(start, folio_start) - folio_start;
 334                         unsigned folio_len = min(end, folio_end) - folio_offset - folio_start;
 335                         struct bch_folio *s;
 336
 337                         BUG_ON(end <= folio_start);
 338
 339                         folio_lock(folio);
 340                         s = bch2_folio(folio);
 341
 342                         if (s) {
 343                                 spin_lock(&s->lock);
 344                                 for (j = folio_offset; j < folio_offset + folio_len; j++) {
 345                                         i_sectors_delta -= s->s[j].state == SECTOR_dirty;
 346                                         bch2_folio_sector_set(folio, s, j,
 347                                                 folio_sector_reserve(s->s[j].state));
 348                                 }
 349                                 spin_unlock(&s->lock);
 350                         }
 351
 352                         folio_unlock(folio);
 353                 }
 354                 folio_batch_release(&fbatch);
 355                 cond_resched();
 356         }
 357
 358         bch2_i_sectors_acct(c, inode, NULL, i_sectors_delta);
 359 }
 360
 361 static inline unsigned sectors_to_reserve(struct bch_folio_sector *s,
 362                                           unsigned nr_replicas)
 363 {
 364         return max(0, (int) nr_replicas -
 365                    s->nr_replicas -
 366                    s->replicas_reserved);
 367 }
 368
 369 int bch2_get_folio_disk_reservation(struct bch_fs *c,
 370                                 struct bch_inode_info *inode,
 371                                 struct folio *folio, bool check_enospc)
 372 {
 373         struct bch_folio *s = bch2_folio_create(folio, 0);
 374         unsigned nr_replicas = inode_nr_replicas(c, inode);
 375         struct disk_reservation disk_res = { 0 };
 376         unsigned i, sectors = folio_sectors(folio), disk_res_sectors = 0;
 377         int ret;
 378
 379         if (!s)
 380                 return -ENOMEM;
 381
 382         for (i = 0; i < sectors; i++)
 383                 disk_res_sectors += sectors_to_reserve(&s->s[i], nr_replicas);
 384
 385         if (!disk_res_sectors)
 386                 return 0;
 387
 388         ret = bch2_disk_reservation_get(c, &disk_res,
 389                                         disk_res_sectors, 1,
 390                                         !check_enospc
 391                                         ? BCH_DISK_RESERVATION_NOFAIL
 392                                         : 0);
 393         if (unlikely(ret))
 394                 return ret;
 395
 396         for (i = 0; i < sectors; i++)
 397                 s->s[i].replicas_reserved +=
 398                         sectors_to_reserve(&s->s[i], nr_replicas);
 399
 400         return 0;
 401 }
 402
 403 void bch2_folio_reservation_put(struct bch_fs *c,
 404                         struct bch_inode_info *inode,
 405                         struct bch2_folio_reservation *res)
 406 {
 407         bch2_disk_reservation_put(c, &res->disk);
 408         bch2_quota_reservation_put(c, inode, &res->quota);
 409 }
 410
 411 int bch2_folio_reservation_get(struct bch_fs *c,
 412                         struct bch_inode_info *inode,
 413                         struct folio *folio,
 414                         struct bch2_folio_reservation *res,
 415                         unsigned offset, unsigned len)
 416 {
 417         struct bch_folio *s = bch2_folio_create(folio, 0);
 418         unsigned i, disk_sectors = 0, quota_sectors = 0;
 419         int ret;
 420
 421         if (!s)
 422                 return -ENOMEM;
 423
 424         BUG_ON(!s->uptodate);
 425
 426         for (i = round_down(offset, block_bytes(c)) >> 9;
 427              i < round_up(offset + len, block_bytes(c)) >> 9;
 428              i++) {
 429                 disk_sectors += sectors_to_reserve(&s->s[i],
 430                                                 res->disk.nr_replicas);
 431                 quota_sectors += s->s[i].state == SECTOR_unallocated;
 432         }
 433
 434         if (disk_sectors) {
 435                 ret = bch2_disk_reservation_add(c, &res->disk, disk_sectors, 0);
 436                 if (unlikely(ret))
 437                         return ret;
 438         }
 439
 440         if (quota_sectors) {
 441                 ret = bch2_quota_reservation_add(c, inode, &res->quota,
 442                                                  quota_sectors, true);
 443                 if (unlikely(ret)) {
 444                         struct disk_reservation tmp = {
 445                                 .sectors = disk_sectors
 446                         };
 447
 448                         bch2_disk_reservation_put(c, &tmp);
 449                         res->disk.sectors -= disk_sectors;
 450                         return ret;
 451                 }
 452         }
 453
 454         return 0;
 455 }
 456
 457 static void bch2_clear_folio_bits(struct folio *folio)
 458 {
 459         struct bch_inode_info *inode = to_bch_ei(folio->mapping->host);
 460         struct bch_fs *c = inode->v.i_sb->s_fs_info;
 461         struct bch_folio *s = bch2_folio(folio);
 462         struct disk_reservation disk_res = { 0 };
 463         int i, sectors = folio_sectors(folio), dirty_sectors = 0;
 464
 465         if (!s)
 466                 return;
 467
 468         EBUG_ON(!folio_test_locked(folio));
 469         EBUG_ON(folio_test_writeback(folio));
 470
 471         for (i = 0; i < sectors; i++) {
 472                 disk_res.sectors += s->s[i].replicas_reserved;
 473                 s->s[i].replicas_reserved = 0;
 474
 475                 dirty_sectors -= s->s[i].state == SECTOR_dirty;
 476                 bch2_folio_sector_set(folio, s, i, folio_sector_undirty(s->s[i].state));
 477         }
 478
 479         bch2_disk_reservation_put(c, &disk_res);
 480
 481         bch2_i_sectors_acct(c, inode, NULL, dirty_sectors);
 482
 483         bch2_folio_release(folio);
 484 }
 485
 486 void bch2_set_folio_dirty(struct bch_fs *c,
 487                           struct bch_inode_info *inode,
 488                           struct folio *folio,
 489                           struct bch2_folio_reservation *res,
 490                           unsigned offset, unsigned len)
 491 {
 492         struct bch_folio *s = bch2_folio(folio);
 493         unsigned i, dirty_sectors = 0;
 494
 495         WARN_ON((u64) folio_pos(folio) + offset + len >
 496                 round_up((u64) i_size_read(&inode->v), block_bytes(c)));
 497
 498         BUG_ON(!s->uptodate);
 499
 500         spin_lock(&s->lock);
 501
 502         for (i = round_down(offset, block_bytes(c)) >> 9;
 503              i < round_up(offset + len, block_bytes(c)) >> 9;
 504              i++) {
 505                 unsigned sectors = sectors_to_reserve(&s->s[i],
 506                                                 res->disk.nr_replicas);
 507
 508                 /*
 509                  * This can happen if we race with the error path in
 510                  * bch2_writepage_io_done():
 511                  */
 512                 sectors = min_t(unsigned, sectors, res->disk.sectors);
 513
 514                 s->s[i].replicas_reserved += sectors;
 515                 res->disk.sectors -= sectors;
 516
 517                 dirty_sectors += s->s[i].state == SECTOR_unallocated;
 518
 519                 bch2_folio_sector_set(folio, s, i, folio_sector_dirty(s->s[i].state));
 520         }
 521
 522         spin_unlock(&s->lock);
 523
 524         bch2_i_sectors_acct(c, inode, &res->quota, dirty_sectors);
 525
 526         if (!folio_test_dirty(folio))
 527                 filemap_dirty_folio(inode->v.i_mapping, folio);
 528 }
 529
 530 vm_fault_t bch2_page_fault(struct vm_fault *vmf)
 531 {
 532         struct file *file = vmf->vma->vm_file;
 533         struct address_space *mapping = file->f_mapping;
 534         struct address_space *fdm = faults_disabled_mapping();
 535         struct bch_inode_info *inode = file_bch_inode(file);
 536         vm_fault_t ret;
 537
 538         if (fdm == mapping)
 539                 return VM_FAULT_SIGBUS;
 540
 541         /* Lock ordering: */
 542         if (fdm > mapping) {
 543                 struct bch_inode_info *fdm_host = to_bch_ei(fdm->host);
 544
 545                 if (bch2_pagecache_add_tryget(inode))
 546                         goto got_lock;
 547
 548                 bch2_pagecache_block_put(fdm_host);
 549
 550                 bch2_pagecache_add_get(inode);
 551                 bch2_pagecache_add_put(inode);
 552
 553                 bch2_pagecache_block_get(fdm_host);
 554
 555                 /* Signal that lock has been dropped: */
 556                 set_fdm_dropped_locks();
 557                 return VM_FAULT_SIGBUS;
 558         }
 559
 560         bch2_pagecache_add_get(inode);
 561 got_lock:
 562         ret = filemap_fault(vmf);
 563         bch2_pagecache_add_put(inode);
 564
 565         return ret;
 566 }
 567
 568 vm_fault_t bch2_page_mkwrite(struct vm_fault *vmf)
 569 {
 570         struct folio *folio = page_folio(vmf->page);
 571         struct file *file = vmf->vma->vm_file;
 572         struct bch_inode_info *inode = file_bch_inode(file);
 573         struct address_space *mapping = file->f_mapping;
 574         struct bch_fs *c = inode->v.i_sb->s_fs_info;
 575         struct bch2_folio_reservation res;
 576         unsigned len;
 577         loff_t isize;
 578         vm_fault_t ret;
 579
 580         bch2_folio_reservation_init(c, inode, &res);
 581
 582         sb_start_pagefault(inode->v.i_sb);
 583         file_update_time(file);
 584
 585         /*
 586          * Not strictly necessary, but helps avoid dio writes livelocking in
 587          * bch2_write_invalidate_inode_pages_range() - can drop this if/when we get
 588          * a bch2_write_invalidate_inode_pages_range() that works without dropping
 589          * page lock before invalidating page
 590          */
 591         bch2_pagecache_add_get(inode);
 592
 593         folio_lock(folio);
 594         isize = i_size_read(&inode->v);
 595
 596         if (folio->mapping != mapping || folio_pos(folio) >= isize) {
 597                 folio_unlock(folio);
 598                 ret = VM_FAULT_NOPAGE;
 599                 goto out;
 600         }
 601
 602         len = min_t(loff_t, folio_size(folio), isize - folio_pos(folio));
 603
 604         if (bch2_folio_set(c, inode_inum(inode), &folio, 1) ?:
 605             bch2_folio_reservation_get(c, inode, folio, &res, 0, len)) {
 606                 folio_unlock(folio);
 607                 ret = VM_FAULT_SIGBUS;
 608                 goto out;
 609         }
 610
 611         bch2_set_folio_dirty(c, inode, folio, &res, 0, len);
 612         bch2_folio_reservation_put(c, inode, &res);
 613
 614         folio_wait_stable(folio);
 615         ret = VM_FAULT_LOCKED;
 616 out:
 617         bch2_pagecache_add_put(inode);
 618         sb_end_pagefault(inode->v.i_sb);
 619
 620         return ret;
 621 }
 622
 623 void bch2_invalidate_folio(struct folio *folio, size_t offset, size_t length)
 624 {
 625         if (offset || length < folio_size(folio))
 626                 return;
 627
 628         bch2_clear_folio_bits(folio);
 629 }
 630
 631 bool bch2_release_folio(struct folio *folio, gfp_t gfp_mask)
 632 {
 633         if (folio_test_dirty(folio) || folio_test_writeback(folio))
 634                 return false;
 635
 636         bch2_clear_folio_bits(folio);
 637         return true;
 638 }
 639
 640 /* fseek: */
 641
 642 static int folio_data_offset(struct folio *folio, loff_t pos,
 643                              unsigned min_replicas)
 644 {
 645         struct bch_folio *s = bch2_folio(folio);
 646         unsigned i, sectors = folio_sectors(folio);
 647
 648         if (s)
 649                 for (i = folio_pos_to_s(folio, pos); i < sectors; i++)
 650                         if (s->s[i].state >= SECTOR_dirty &&
 651                             s->s[i].nr_replicas + s->s[i].replicas_reserved >= min_replicas)
 652                                 return i << SECTOR_SHIFT;
 653
 654         return -1;
 655 }
 656
 657 loff_t bch2_seek_pagecache_data(struct inode *vinode,
 658                                 loff_t start_offset,
 659                                 loff_t end_offset,
 660                                 unsigned min_replicas,
 661                                 bool nonblock)
 662 {
 663         struct folio_batch fbatch;
 664         pgoff_t start_index     = start_offset >> PAGE_SHIFT;
 665         pgoff_t end_index       = end_offset >> PAGE_SHIFT;
 666         pgoff_t index           = start_index;
 667         unsigned i;
 668         loff_t ret;
 669         int offset;
 670
 671         folio_batch_init(&fbatch);
 672
 673         while (filemap_get_folios(vinode->i_mapping,
 674                                   &index, end_index, &fbatch)) {
 675                 for (i = 0; i < folio_batch_count(&fbatch); i++) {
 676                         struct folio *folio = fbatch.folios[i];
 677
 678                         if (!nonblock) {
 679                                 folio_lock(folio);
 680                         } else if (!folio_trylock(folio)) {
 681                                 folio_batch_release(&fbatch);
 682                                 return -EAGAIN;
 683                         }
 684
 685                         offset = folio_data_offset(folio,
 686                                         max(folio_pos(folio), start_offset),
 687                                         min_replicas);
 688                         if (offset >= 0) {
 689                                 ret = clamp(folio_pos(folio) + offset,
 690                                             start_offset, end_offset);
 691                                 folio_unlock(folio);
 692                                 folio_batch_release(&fbatch);
 693                                 return ret;
 694                         }
 695                         folio_unlock(folio);
 696                 }
 697                 folio_batch_release(&fbatch);
 698                 cond_resched();
 699         }
 700
 701         return end_offset;
 702 }
 703
 704 /*
 705  * Search for a hole in a folio.
 706  *
 707  * The filemap layer returns -ENOENT if no folio exists, so reuse the same error
 708  * code to indicate a pagecache hole exists at the returned offset. Otherwise
 709  * return 0 if the folio is filled with data, or an error code. This function
 710  * can return -EAGAIN if nonblock is specified.
 711  */
 712 static int folio_hole_offset(struct address_space *mapping, loff_t *offset,
 713                               unsigned min_replicas, bool nonblock)
 714 {
 715         struct folio *folio;
 716         struct bch_folio *s;
 717         unsigned i, sectors;
 718         int ret = -ENOENT;
 719
 720         folio = __filemap_get_folio(mapping, *offset >> PAGE_SHIFT,
 721                                     FGP_LOCK|(nonblock ? FGP_NOWAIT : 0), 0);
 722         if (IS_ERR(folio))
 723                 return PTR_ERR(folio);
 724
 725         s = bch2_folio(folio);
 726         if (!s)
 727                 goto unlock;
 728
 729         sectors = folio_sectors(folio);
 730         for (i = folio_pos_to_s(folio, *offset); i < sectors; i++)
 731                 if (s->s[i].state < SECTOR_dirty ||
 732                     s->s[i].nr_replicas + s->s[i].replicas_reserved < min_replicas) {
 733                         *offset = max(*offset,
 734                                       folio_pos(folio) + (i << SECTOR_SHIFT));
 735                         goto unlock;
 736                 }
 737
 738         *offset = folio_end_pos(folio);
 739         ret = 0;
 740 unlock:
 741         folio_unlock(folio);
 742         folio_put(folio);
 743         return ret;
 744 }
 745
 746 loff_t bch2_seek_pagecache_hole(struct inode *vinode,
 747                                 loff_t start_offset,
 748                                 loff_t end_offset,
 749                                 unsigned min_replicas,
 750                                 bool nonblock)
 751 {
 752         struct address_space *mapping = vinode->i_mapping;
 753         loff_t offset = start_offset;
 754         loff_t ret = 0;
 755
 756         while (!ret && offset < end_offset)
 757                 ret = folio_hole_offset(mapping, &offset, min_replicas, nonblock);
 758
 759         if (ret && ret != -ENOENT)
 760                 return ret;
 761         return min(offset, end_offset);
 762 }
 763
 764 int bch2_clamp_data_hole(struct inode *inode,
 765                          u64 *hole_start,
 766                          u64 *hole_end,
 767                          unsigned min_replicas,
 768                          bool nonblock)
 769 {
 770         loff_t ret;
 771
 772         ret = bch2_seek_pagecache_hole(inode,
 773                 *hole_start << 9, *hole_end << 9, min_replicas, nonblock) >> 9;
 774         if (ret < 0)
 775                 return ret;
 776
 777         *hole_start = ret;
 778
 779         if (*hole_start == *hole_end)
 780                 return 0;
 781
 782         ret = bch2_seek_pagecache_data(inode,
 783                 *hole_start << 9, *hole_end << 9, min_replicas, nonblock) >> 9;
 784         if (ret < 0)
 785                 return ret;
 786
 787         *hole_end = ret;
 788         return 0;
 789 }
 790
 791 #endif /* NO_BCACHEFS_FS */