1 // SPDX-License-Identifier: GPL-2.0 2 #ifndef NO_BCACHEFS_FS 3 4 #include "bcachefs.h" 5 #include "alloc_foreground.h" 6 #include "bkey_buf.h" 7 #include "fs-io.h" 8 #include "fs-io-buffered.h" 9 #include "fs-io-direct.h" 10 #include "fs-io-pagecache.h" 11 #include "io_read.h" 12 #include "io_write.h" 13 14 #include <linux/backing-dev.h> 15 #include <linux/pagemap.h> 16 #include <linux/writeback.h> 17 18 static inline bool bio_full(struct bio *bio, unsigned len) 19 { 20 if (bio->bi_vcnt >= bio->bi_max_vecs) 21 return true; 22 if (bio->bi_iter.bi_size > UINT_MAX - len) 23 return true; 24 return false; 25 } 26 27 /* readpage(s): */ 28 29 static void bch2_readpages_end_io(struct bio *bio) 30 { 31 struct folio_iter fi; 32 33 bio_for_each_folio_all(fi, bio) { 34 if (!bio->bi_status) { 35 folio_mark_uptodate(fi.folio); 36 } else { 37 folio_clear_uptodate(fi.folio); 38 folio_set_error(fi.folio); 39 } 40 folio_unlock(fi.folio); 41 } 42 43 bio_put(bio); 44 } 45 46 struct readpages_iter { 47 struct address_space *mapping; 48 unsigned idx; 49 folios folios; 50 }; 51 52 static int readpages_iter_init(struct readpages_iter *iter, 53 struct readahead_control *ractl) 54 { 55 struct folio **fi; 56 int ret; 57 58 memset(iter, 0, sizeof(*iter)); 59 60 iter->mapping = ractl->mapping; 61 62 ret = bch2_filemap_get_contig_folios_d(iter->mapping, 63 ractl->_index << PAGE_SHIFT, 64 (ractl->_index + ractl->_nr_pages) << PAGE_SHIFT, 65 0, mapping_gfp_mask(iter->mapping), 66 &iter->folios); 67 if (ret) 68 return ret; 69 70 darray_for_each(iter->folios, fi) { 71 ractl->_nr_pages -= 1U << folio_order(*fi); 72 __bch2_folio_create(*fi, __GFP_NOFAIL|GFP_KERNEL); 73 folio_put(*fi); 74 folio_put(*fi); 75 } 76 77 return 0; 78 } 79 80 static inline struct folio *readpage_iter_peek(struct readpages_iter *iter) 81 { 82 if (iter->idx >= iter->folios.nr) 83 return NULL; 84 return iter->folios.data[iter->idx]; 85 } 86 87 static inline void readpage_iter_advance(struct readpages_iter *iter) 88 { 89 iter->idx++; 90 } 91 92 static bool extent_partial_reads_expensive(struct bkey_s_c k) 93 { 94 struct bkey_ptrs_c ptrs = bch2_bkey_ptrs_c(k); 95 struct bch_extent_crc_unpacked crc; 96 const union bch_extent_entry *i; 97 98 bkey_for_each_crc(k.k, ptrs, crc, i) 99 if (crc.csum_type || crc.compression_type) 100 return true; 101 return false; 102 } 103 104 static int readpage_bio_extend(struct btree_trans *trans, 105 struct readpages_iter *iter, 106 struct bio *bio, 107 unsigned sectors_this_extent, 108 bool get_more) 109 { 110 /* Don't hold btree locks while allocating memory: */ 111 bch2_trans_unlock(trans); 112 113 while (bio_sectors(bio) < sectors_this_extent && 114 bio->bi_vcnt < bio->bi_max_vecs) { 115 struct folio *folio = readpage_iter_peek(iter); 116 int ret; 117 118 if (folio) { 119 readpage_iter_advance(iter); 120 } else { 121 pgoff_t folio_offset = bio_end_sector(bio) >> PAGE_SECTORS_SHIFT; 122 123 if (!get_more) 124 break; 125 126 folio = xa_load(&iter->mapping->i_pages, folio_offset); 127 if (folio && !xa_is_value(folio)) 128 break; 129 130 folio = filemap_alloc_folio(readahead_gfp_mask(iter->mapping), 0); 131 if (!folio) 132 break; 133 134 if (!__bch2_folio_create(folio, GFP_KERNEL)) { 135 folio_put(folio); 136 break; 137 } 138 139 ret = filemap_add_folio(iter->mapping, folio, folio_offset, GFP_KERNEL); 140 if (ret) { 141 __bch2_folio_release(folio); 142 folio_put(folio); 143 break; 144 } 145 146 folio_put(folio); 147 } 148 149 BUG_ON(folio_sector(folio) != bio_end_sector(bio)); 150 151 BUG_ON(!bio_add_folio(bio, folio, folio_size(folio), 0)); 152 } 153 154 return bch2_trans_relock(trans); 155 } 156 157 static void bchfs_read(struct btree_trans *trans, 158 struct bch_read_bio *rbio, 159 subvol_inum inum, 160 struct readpages_iter *readpages_iter) 161 { 162 struct bch_fs *c = trans->c; 163 struct btree_iter iter; 164 struct bkey_buf sk; 165 int flags = BCH_READ_RETRY_IF_STALE| 166 BCH_READ_MAY_PROMOTE; 167 u32 snapshot; 168 int ret = 0; 169 170 rbio->c = c; 171 rbio->start_time = local_clock(); 172 rbio->subvol = inum.subvol; 173 174 bch2_bkey_buf_init(&sk); 175 retry: 176 bch2_trans_begin(trans); 177 iter = (struct btree_iter) { NULL }; 178 179 ret = bch2_subvolume_get_snapshot(trans, inum.subvol, &snapshot); 180 if (ret) 181 goto err; 182 183 bch2_trans_iter_init(trans, &iter, BTREE_ID_extents, 184 SPOS(inum.inum, rbio->bio.bi_iter.bi_sector, snapshot), 185 BTREE_ITER_SLOTS); 186 while (1) { 187 struct bkey_s_c k; 188 unsigned bytes, sectors, offset_into_extent; 189 enum btree_id data_btree = BTREE_ID_extents; 190 191 /* 192 * read_extent -> io_time_reset may cause a transaction restart 193 * without returning an error, we need to check for that here: 194 */ 195 ret = bch2_trans_relock(trans); 196 if (ret) 197 break; 198 199 bch2_btree_iter_set_pos(&iter, 200 POS(inum.inum, rbio->bio.bi_iter.bi_sector)); 201 202 k = bch2_btree_iter_peek_slot(&iter); 203 ret = bkey_err(k); 204 if (ret) 205 break; 206 207 offset_into_extent = iter.pos.offset - 208 bkey_start_offset(k.k); 209 sectors = k.k->size - offset_into_extent; 210 211 bch2_bkey_buf_reassemble(&sk, c, k); 212 213 ret = bch2_read_indirect_extent(trans, &data_btree, 214 &offset_into_extent, &sk); 215 if (ret) 216 break; 217 218 k = bkey_i_to_s_c(sk.k); 219 220 sectors = min(sectors, k.k->size - offset_into_extent); 221 222 if (readpages_iter) { 223 ret = readpage_bio_extend(trans, readpages_iter, &rbio->bio, sectors, 224 extent_partial_reads_expensive(k)); 225 if (ret) 226 break; 227 } 228 229 bytes = min(sectors, bio_sectors(&rbio->bio)) << 9; 230 swap(rbio->bio.bi_iter.bi_size, bytes); 231 232 if (rbio->bio.bi_iter.bi_size == bytes) 233 flags |= BCH_READ_LAST_FRAGMENT; 234 235 bch2_bio_page_state_set(&rbio->bio, k); 236 237 bch2_read_extent(trans, rbio, iter.pos, 238 data_btree, k, offset_into_extent, flags); 239 240 if (flags & BCH_READ_LAST_FRAGMENT) 241 break; 242 243 swap(rbio->bio.bi_iter.bi_size, bytes); 244 bio_advance(&rbio->bio, bytes); 245 246 ret = btree_trans_too_many_iters(trans); 247 if (ret) 248 break; 249 } 250 err: 251 bch2_trans_iter_exit(trans, &iter); 252 253 if (bch2_err_matches(ret, BCH_ERR_transaction_restart)) 254 goto retry; 255 256 if (ret) { 257 bch_err_inum_offset_ratelimited(c, 258 iter.pos.inode, 259 iter.pos.offset << 9, 260 "read error %i from btree lookup", ret); 261 rbio->bio.bi_status = BLK_STS_IOERR; 262 bio_endio(&rbio->bio); 263 } 264 265 bch2_bkey_buf_exit(&sk, c); 266 } 267 268 void bch2_readahead(struct readahead_control *ractl) 269 { 270 struct bch_inode_info *inode = to_bch_ei(ractl->mapping->host); 271 struct bch_fs *c = inode->v.i_sb->s_fs_info; 272 struct bch_io_opts opts; 273 struct btree_trans *trans = bch2_trans_get(c); 274 struct folio *folio; 275 struct readpages_iter readpages_iter; 276 int ret; 277 278 bch2_inode_opts_get(&opts, c, &inode->ei_inode); 279 280 ret = readpages_iter_init(&readpages_iter, ractl); 281 BUG_ON(ret); 282 283 bch2_pagecache_add_get(inode); 284 285 while ((folio = readpage_iter_peek(&readpages_iter))) { 286 unsigned n = min_t(unsigned, 287 readpages_iter.folios.nr - 288 readpages_iter.idx, 289 BIO_MAX_VECS); 290 struct bch_read_bio *rbio = 291 rbio_init(bio_alloc_bioset(NULL, n, REQ_OP_READ, 292 GFP_KERNEL, &c->bio_read), 293 opts); 294 295 readpage_iter_advance(&readpages_iter); 296 297 rbio->bio.bi_iter.bi_sector = folio_sector(folio); 298 rbio->bio.bi_end_io = bch2_readpages_end_io; 299 BUG_ON(!bio_add_folio(&rbio->bio, folio, folio_size(folio), 0)); 300 301 bchfs_read(trans, rbio, inode_inum(inode), 302 &readpages_iter); 303 bch2_trans_unlock(trans); 304 } 305 306 bch2_pagecache_add_put(inode); 307 308 bch2_trans_put(trans); 309 darray_exit(&readpages_iter.folios); 310 } 311 312 static void __bchfs_readfolio(struct bch_fs *c, struct bch_read_bio *rbio, 313 subvol_inum inum, struct folio *folio) 314 { 315 bch2_folio_create(folio, __GFP_NOFAIL); 316 317 rbio->bio.bi_opf = REQ_OP_READ|REQ_SYNC; 318 rbio->bio.bi_iter.bi_sector = folio_sector(folio); 319 BUG_ON(!bio_add_folio(&rbio->bio, folio, folio_size(folio), 0)); 320 321 bch2_trans_run(c, (bchfs_read(trans, rbio, inum, NULL), 0)); 322 } 323 324 static void bch2_read_single_folio_end_io(struct bio *bio) 325 { 326 complete(bio->bi_private); 327 } 328 329 int bch2_read_single_folio(struct folio *folio, struct address_space *mapping) 330 { 331 struct bch_inode_info *inode = to_bch_ei(mapping->host); 332 struct bch_fs *c = inode->v.i_sb->s_fs_info; 333 struct bch_read_bio *rbio; 334 struct bch_io_opts opts; 335 int ret; 336 DECLARE_COMPLETION_ONSTACK(done); 337 338 bch2_inode_opts_get(&opts, c, &inode->ei_inode); 339 340 rbio = rbio_init(bio_alloc_bioset(NULL, 1, REQ_OP_READ, GFP_KERNEL, &c->bio_read), 341 opts); 342 rbio->bio.bi_private = &done; 343 rbio->bio.bi_end_io = bch2_read_single_folio_end_io; 344 345 __bchfs_readfolio(c, rbio, inode_inum(inode), folio); 346 wait_for_completion(&done); 347 348 ret = blk_status_to_errno(rbio->bio.bi_status); 349 bio_put(&rbio->bio); 350 351 if (ret < 0) 352 return ret; 353 354 folio_mark_uptodate(folio); 355 return 0; 356 } 357 358 int bch2_read_folio(struct file *file, struct folio *folio) 359 { 360 int ret; 361 362 ret = bch2_read_single_folio(folio, folio->mapping); 363 folio_unlock(folio); 364 return bch2_err_class(ret); 365 } 366 367 /* writepages: */ 368 369 struct bch_writepage_io { 370 struct bch_inode_info *inode; 371 372 /* must be last: */ 373 struct bch_write_op op; 374 }; 375 376 struct bch_writepage_state { 377 struct bch_writepage_io *io; 378 struct bch_io_opts opts; 379 struct bch_folio_sector *tmp; 380 unsigned tmp_sectors; 381 }; 382 383 static inline struct bch_writepage_state bch_writepage_state_init(struct bch_fs *c, 384 struct bch_inode_info *inode) 385 { 386 struct bch_writepage_state ret = { 0 }; 387 388 bch2_inode_opts_get(&ret.opts, c, &inode->ei_inode); 389 return ret; 390 } 391 392 static void bch2_writepage_io_done(struct bch_write_op *op) 393 { 394 struct bch_writepage_io *io = 395 container_of(op, struct bch_writepage_io, op); 396 struct bch_fs *c = io->op.c; 397 struct bio *bio = &io->op.wbio.bio; 398 struct folio_iter fi; 399 unsigned i; 400 401 if (io->op.error) { 402 set_bit(EI_INODE_ERROR, &io->inode->ei_flags); 403 404 bio_for_each_folio_all(fi, bio) { 405 struct bch_folio *s; 406 407 folio_set_error(fi.folio); 408 mapping_set_error(fi.folio->mapping, -EIO); 409 410 s = __bch2_folio(fi.folio); 411 spin_lock(&s->lock); 412 for (i = 0; i < folio_sectors(fi.folio); i++) 413 s->s[i].nr_replicas = 0; 414 spin_unlock(&s->lock); 415 } 416 } 417 418 if (io->op.flags & BCH_WRITE_WROTE_DATA_INLINE) { 419 bio_for_each_folio_all(fi, bio) { 420 struct bch_folio *s; 421 422 s = __bch2_folio(fi.folio); 423 spin_lock(&s->lock); 424 for (i = 0; i < folio_sectors(fi.folio); i++) 425 s->s[i].nr_replicas = 0; 426 spin_unlock(&s->lock); 427 } 428 } 429 430 /* 431 * racing with fallocate can cause us to add fewer sectors than 432 * expected - but we shouldn't add more sectors than expected: 433 */ 434 WARN_ON_ONCE(io->op.i_sectors_delta > 0); 435 436 /* 437 * (error (due to going RO) halfway through a page can screw that up 438 * slightly) 439 * XXX wtf? 440 BUG_ON(io->op.op.i_sectors_delta >= PAGE_SECTORS); 441 */ 442 443 /* 444 * PageWriteback is effectively our ref on the inode - fixup i_blocks 445 * before calling end_page_writeback: 446 */ 447 bch2_i_sectors_acct(c, io->inode, NULL, io->op.i_sectors_delta); 448 449 bio_for_each_folio_all(fi, bio) { 450 struct bch_folio *s = __bch2_folio(fi.folio); 451 452 if (atomic_dec_and_test(&s->write_count)) 453 folio_end_writeback(fi.folio); 454 } 455 456 bio_put(&io->op.wbio.bio); 457 } 458 459 static void bch2_writepage_do_io(struct bch_writepage_state *w) 460 { 461 struct bch_writepage_io *io = w->io; 462 463 w->io = NULL; 464 closure_call(&io->op.cl, bch2_write, NULL, NULL); 465 } 466 467 /* 468 * Get a bch_writepage_io and add @page to it - appending to an existing one if 469 * possible, else allocating a new one: 470 */ 471 static void bch2_writepage_io_alloc(struct bch_fs *c, 472 struct writeback_control *wbc, 473 struct bch_writepage_state *w, 474 struct bch_inode_info *inode, 475 u64 sector, 476 unsigned nr_replicas) 477 { 478 struct bch_write_op *op; 479 480 w->io = container_of(bio_alloc_bioset(NULL, BIO_MAX_VECS, 481 REQ_OP_WRITE, 482 GFP_KERNEL, 483 &c->writepage_bioset), 484 struct bch_writepage_io, op.wbio.bio); 485 486 w->io->inode = inode; 487 op = &w->io->op; 488 bch2_write_op_init(op, c, w->opts); 489 op->target = w->opts.foreground_target; 490 op->nr_replicas = nr_replicas; 491 op->res.nr_replicas = nr_replicas; 492 op->write_point = writepoint_hashed(inode->ei_last_dirtied); 493 op->subvol = inode->ei_subvol; 494 op->pos = POS(inode->v.i_ino, sector); 495 op->end_io = bch2_writepage_io_done; 496 op->devs_need_flush = &inode->ei_devs_need_flush; 497 op->wbio.bio.bi_iter.bi_sector = sector; 498 op->wbio.bio.bi_opf = wbc_to_write_flags(wbc); 499 } 500 501 static int __bch2_writepage(struct folio *folio, 502 struct writeback_control *wbc, 503 void *data) 504 { 505 struct bch_inode_info *inode = to_bch_ei(folio->mapping->host); 506 struct bch_fs *c = inode->v.i_sb->s_fs_info; 507 struct bch_writepage_state *w = data; 508 struct bch_folio *s; 509 unsigned i, offset, f_sectors, nr_replicas_this_write = U32_MAX; 510 loff_t i_size = i_size_read(&inode->v); 511 int ret; 512 513 EBUG_ON(!folio_test_uptodate(folio)); 514 515 /* Is the folio fully inside i_size? */ 516 if (folio_end_pos(folio) <= i_size) 517 goto do_io; 518 519 /* Is the folio fully outside i_size? (truncate in progress) */ 520 if (folio_pos(folio) >= i_size) { 521 folio_unlock(folio); 522 return 0; 523 } 524 525 /* 526 * The folio straddles i_size. It must be zeroed out on each and every 527 * writepage invocation because it may be mmapped. "A file is mapped 528 * in multiples of the folio size. For a file that is not a multiple of 529 * the folio size, the remaining memory is zeroed when mapped, and 530 * writes to that region are not written out to the file." 531 */ 532 folio_zero_segment(folio, 533 i_size - folio_pos(folio), 534 folio_size(folio)); 535 do_io: 536 f_sectors = folio_sectors(folio); 537 s = bch2_folio(folio); 538 539 if (f_sectors > w->tmp_sectors) { 540 kfree(w->tmp); 541 w->tmp = kcalloc(f_sectors, sizeof(struct bch_folio_sector), __GFP_NOFAIL); 542 w->tmp_sectors = f_sectors; 543 } 544 545 /* 546 * Things get really hairy with errors during writeback: 547 */ 548 ret = bch2_get_folio_disk_reservation(c, inode, folio, false); 549 BUG_ON(ret); 550 551 /* Before unlocking the page, get copy of reservations: */ 552 spin_lock(&s->lock); 553 memcpy(w->tmp, s->s, sizeof(struct bch_folio_sector) * f_sectors); 554 555 for (i = 0; i < f_sectors; i++) { 556 if (s->s[i].state < SECTOR_dirty) 557 continue; 558 559 nr_replicas_this_write = 560 min_t(unsigned, nr_replicas_this_write, 561 s->s[i].nr_replicas + 562 s->s[i].replicas_reserved); 563 } 564 565 for (i = 0; i < f_sectors; i++) { 566 if (s->s[i].state < SECTOR_dirty) 567 continue; 568 569 s->s[i].nr_replicas = w->opts.compression 570 ? 0 : nr_replicas_this_write; 571 572 s->s[i].replicas_reserved = 0; 573 bch2_folio_sector_set(folio, s, i, SECTOR_allocated); 574 } 575 spin_unlock(&s->lock); 576 577 BUG_ON(atomic_read(&s->write_count)); 578 atomic_set(&s->write_count, 1); 579 580 BUG_ON(folio_test_writeback(folio)); 581 folio_start_writeback(folio); 582 583 folio_unlock(folio); 584 585 offset = 0; 586 while (1) { 587 unsigned sectors = 0, dirty_sectors = 0, reserved_sectors = 0; 588 u64 sector; 589 590 while (offset < f_sectors && 591 w->tmp[offset].state < SECTOR_dirty) 592 offset++; 593 594 if (offset == f_sectors) 595 break; 596 597 while (offset + sectors < f_sectors && 598 w->tmp[offset + sectors].state >= SECTOR_dirty) { 599 reserved_sectors += w->tmp[offset + sectors].replicas_reserved; 600 dirty_sectors += w->tmp[offset + sectors].state == SECTOR_dirty; 601 sectors++; 602 } 603 BUG_ON(!sectors); 604 605 sector = folio_sector(folio) + offset; 606 607 if (w->io && 608 (w->io->op.res.nr_replicas != nr_replicas_this_write || 609 bio_full(&w->io->op.wbio.bio, sectors << 9) || 610 w->io->op.wbio.bio.bi_iter.bi_size + (sectors << 9) >= 611 (BIO_MAX_VECS * PAGE_SIZE) || 612 bio_end_sector(&w->io->op.wbio.bio) != sector)) 613 bch2_writepage_do_io(w); 614 615 if (!w->io) 616 bch2_writepage_io_alloc(c, wbc, w, inode, sector, 617 nr_replicas_this_write); 618 619 atomic_inc(&s->write_count); 620 621 BUG_ON(inode != w->io->inode); 622 BUG_ON(!bio_add_folio(&w->io->op.wbio.bio, folio, 623 sectors << 9, offset << 9)); 624 625 /* Check for writing past i_size: */ 626 WARN_ONCE((bio_end_sector(&w->io->op.wbio.bio) << 9) > 627 round_up(i_size, block_bytes(c)) && 628 !test_bit(BCH_FS_EMERGENCY_RO, &c->flags), 629 "writing past i_size: %llu > %llu (unrounded %llu)\n", 630 bio_end_sector(&w->io->op.wbio.bio) << 9, 631 round_up(i_size, block_bytes(c)), 632 i_size); 633 634 w->io->op.res.sectors += reserved_sectors; 635 w->io->op.i_sectors_delta -= dirty_sectors; 636 w->io->op.new_i_size = i_size; 637 638 offset += sectors; 639 } 640 641 if (atomic_dec_and_test(&s->write_count)) 642 folio_end_writeback(folio); 643 644 return 0; 645 } 646 647 int bch2_writepages(struct address_space *mapping, struct writeback_control *wbc) 648 { 649 struct bch_fs *c = mapping->host->i_sb->s_fs_info; 650 struct bch_writepage_state w = 651 bch_writepage_state_init(c, to_bch_ei(mapping->host)); 652 struct blk_plug plug; 653 int ret; 654 655 blk_start_plug(&plug); 656 ret = write_cache_pages(mapping, wbc, __bch2_writepage, &w); 657 if (w.io) 658 bch2_writepage_do_io(&w); 659 blk_finish_plug(&plug); 660 kfree(w.tmp); 661 return bch2_err_class(ret); 662 } 663 664 /* buffered writes: */ 665 666 int bch2_write_begin(struct file *file, struct address_space *mapping, 667 loff_t pos, unsigned len, 668 struct page **pagep, void **fsdata) 669 { 670 struct bch_inode_info *inode = to_bch_ei(mapping->host); 671 struct bch_fs *c = inode->v.i_sb->s_fs_info; 672 struct bch2_folio_reservation *res; 673 struct folio *folio; 674 unsigned offset; 675 int ret = -ENOMEM; 676 677 res = kmalloc(sizeof(*res), GFP_KERNEL); 678 if (!res) 679 return -ENOMEM; 680 681 bch2_folio_reservation_init(c, inode, res); 682 *fsdata = res; 683 684 bch2_pagecache_add_get(inode); 685 686 folio = __filemap_get_folio(mapping, pos >> PAGE_SHIFT, 687 FGP_LOCK|FGP_WRITE|FGP_CREAT|FGP_STABLE, 688 mapping_gfp_mask(mapping)); 689 if (IS_ERR_OR_NULL(folio)) 690 goto err_unlock; 691 692 offset = pos - folio_pos(folio); 693 len = min_t(size_t, len, folio_end_pos(folio) - pos); 694 695 if (folio_test_uptodate(folio)) 696 goto out; 697 698 /* If we're writing entire folio, don't need to read it in first: */ 699 if (!offset && len == folio_size(folio)) 700 goto out; 701 702 if (!offset && pos + len >= inode->v.i_size) { 703 folio_zero_segment(folio, len, folio_size(folio)); 704 flush_dcache_folio(folio); 705 goto out; 706 } 707 708 if (folio_pos(folio) >= inode->v.i_size) { 709 folio_zero_segments(folio, 0, offset, offset + len, folio_size(folio)); 710 flush_dcache_folio(folio); 711 goto out; 712 } 713 readpage: 714 ret = bch2_read_single_folio(folio, mapping); 715 if (ret) 716 goto err; 717 out: 718 ret = bch2_folio_set(c, inode_inum(inode), &folio, 1); 719 if (ret) 720 goto err; 721 722 ret = bch2_folio_reservation_get(c, inode, folio, res, offset, len); 723 if (ret) { 724 if (!folio_test_uptodate(folio)) { 725 /* 726 * If the folio hasn't been read in, we won't know if we 727 * actually need a reservation - we don't actually need 728 * to read here, we just need to check if the folio is 729 * fully backed by uncompressed data: 730 */ 731 goto readpage; 732 } 733 734 goto err; 735 } 736 737 *pagep = &folio->page; 738 return 0; 739 err: 740 folio_unlock(folio); 741 folio_put(folio); 742 *pagep = NULL; 743 err_unlock: 744 bch2_pagecache_add_put(inode); 745 kfree(res); 746 *fsdata = NULL; 747 return bch2_err_class(ret); 748 } 749 750 int bch2_write_end(struct file *file, struct address_space *mapping, 751 loff_t pos, unsigned len, unsigned copied, 752 struct page *page, void *fsdata) 753 { 754 struct bch_inode_info *inode = to_bch_ei(mapping->host); 755 struct bch_fs *c = inode->v.i_sb->s_fs_info; 756 struct bch2_folio_reservation *res = fsdata; 757 struct folio *folio = page_folio(page); 758 unsigned offset = pos - folio_pos(folio); 759 760 lockdep_assert_held(&inode->v.i_rwsem); 761 BUG_ON(offset + copied > folio_size(folio)); 762 763 if (unlikely(copied < len && !folio_test_uptodate(folio))) { 764 /* 765 * The folio needs to be read in, but that would destroy 766 * our partial write - simplest thing is to just force 767 * userspace to redo the write: 768 */ 769 folio_zero_range(folio, 0, folio_size(folio)); 770 flush_dcache_folio(folio); 771 copied = 0; 772 } 773 774 spin_lock(&inode->v.i_lock); 775 if (pos + copied > inode->v.i_size) 776 i_size_write(&inode->v, pos + copied); 777 spin_unlock(&inode->v.i_lock); 778 779 if (copied) { 780 if (!folio_test_uptodate(folio)) 781 folio_mark_uptodate(folio); 782 783 bch2_set_folio_dirty(c, inode, folio, res, offset, copied); 784 785 inode->ei_last_dirtied = (unsigned long) current; 786 } 787 788 folio_unlock(folio); 789 folio_put(folio); 790 bch2_pagecache_add_put(inode); 791 792 bch2_folio_reservation_put(c, inode, res); 793 kfree(res); 794 795 return copied; 796 } 797 798 static noinline void folios_trunc(folios *fs, struct folio **fi) 799 { 800 while (fs->data + fs->nr > fi) { 801 struct folio *f = darray_pop(fs); 802 803 folio_unlock(f); 804 folio_put(f); 805 } 806 } 807 808 static int __bch2_buffered_write(struct bch_inode_info *inode, 809 struct address_space *mapping, 810 struct iov_iter *iter, 811 loff_t pos, unsigned len) 812 { 813 struct bch_fs *c = inode->v.i_sb->s_fs_info; 814 struct bch2_folio_reservation res; 815 folios fs; 816 struct folio **fi, *f; 817 unsigned copied = 0, f_offset, f_copied; 818 u64 end = pos + len, f_pos, f_len; 819 loff_t last_folio_pos = inode->v.i_size; 820 int ret = 0; 821 822 BUG_ON(!len); 823 824 bch2_folio_reservation_init(c, inode, &res); 825 darray_init(&fs); 826 827 ret = bch2_filemap_get_contig_folios_d(mapping, pos, end, 828 FGP_LOCK|FGP_WRITE|FGP_STABLE|FGP_CREAT, 829 mapping_gfp_mask(mapping), 830 &fs); 831 if (ret) 832 goto out; 833 834 BUG_ON(!fs.nr); 835 836 f = darray_first(fs); 837 if (pos != folio_pos(f) && !folio_test_uptodate(f)) { 838 ret = bch2_read_single_folio(f, mapping); 839 if (ret) 840 goto out; 841 } 842 843 f = darray_last(fs); 844 end = min(end, folio_end_pos(f)); 845 last_folio_pos = folio_pos(f); 846 if (end != folio_end_pos(f) && !folio_test_uptodate(f)) { 847 if (end >= inode->v.i_size) { 848 folio_zero_range(f, 0, folio_size(f)); 849 } else { 850 ret = bch2_read_single_folio(f, mapping); 851 if (ret) 852 goto out; 853 } 854 } 855 856 ret = bch2_folio_set(c, inode_inum(inode), fs.data, fs.nr); 857 if (ret) 858 goto out; 859 860 f_pos = pos; 861 f_offset = pos - folio_pos(darray_first(fs)); 862 darray_for_each(fs, fi) { 863 f = *fi; 864 f_len = min(end, folio_end_pos(f)) - f_pos; 865 866 /* 867 * XXX: per POSIX and fstests generic/275, on -ENOSPC we're 868 * supposed to write as much as we have disk space for. 869 * 870 * On failure here we should still write out a partial page if 871 * we aren't completely out of disk space - we don't do that 872 * yet: 873 */ 874 ret = bch2_folio_reservation_get(c, inode, f, &res, f_offset, f_len); 875 if (unlikely(ret)) { 876 folios_trunc(&fs, fi); 877 if (!fs.nr) 878 goto out; 879 880 end = min(end, folio_end_pos(darray_last(fs))); 881 break; 882 } 883 884 f_pos = folio_end_pos(f); 885 f_offset = 0; 886 } 887 888 if (mapping_writably_mapped(mapping)) 889 darray_for_each(fs, fi) 890 flush_dcache_folio(*fi); 891 892 f_pos = pos; 893 f_offset = pos - folio_pos(darray_first(fs)); 894 darray_for_each(fs, fi) { 895 f = *fi; 896 f_len = min(end, folio_end_pos(f)) - f_pos; 897 f_copied = copy_page_from_iter_atomic(&f->page, f_offset, f_len, iter); 898 if (!f_copied) { 899 folios_trunc(&fs, fi); 900 break; 901 } 902 903 if (!folio_test_uptodate(f) && 904 f_copied != folio_size(f) && 905 pos + copied + f_copied < inode->v.i_size) { 906 iov_iter_revert(iter, f_copied); 907 folio_zero_range(f, 0, folio_size(f)); 908 folios_trunc(&fs, fi); 909 break; 910 } 911 912 flush_dcache_folio(f); 913 copied += f_copied; 914 915 if (f_copied != f_len) { 916 folios_trunc(&fs, fi + 1); 917 break; 918 } 919 920 f_pos = folio_end_pos(f); 921 f_offset = 0; 922 } 923 924 if (!copied) 925 goto out; 926 927 end = pos + copied; 928 929 spin_lock(&inode->v.i_lock); 930 if (end > inode->v.i_size) 931 i_size_write(&inode->v, end); 932 spin_unlock(&inode->v.i_lock); 933 934 f_pos = pos; 935 f_offset = pos - folio_pos(darray_first(fs)); 936 darray_for_each(fs, fi) { 937 f = *fi; 938 f_len = min(end, folio_end_pos(f)) - f_pos; 939 940 if (!folio_test_uptodate(f)) 941 folio_mark_uptodate(f); 942 943 bch2_set_folio_dirty(c, inode, f, &res, f_offset, f_len); 944 945 f_pos = folio_end_pos(f); 946 f_offset = 0; 947 } 948 949 inode->ei_last_dirtied = (unsigned long) current; 950 out: 951 darray_for_each(fs, fi) { 952 folio_unlock(*fi); 953 folio_put(*fi); 954 } 955 956 /* 957 * If the last folio added to the mapping starts beyond current EOF, we 958 * performed a short write but left around at least one post-EOF folio. 959 * Clean up the mapping before we return. 960 */ 961 if (last_folio_pos >= inode->v.i_size) 962 truncate_pagecache(&inode->v, inode->v.i_size); 963 964 darray_exit(&fs); 965 bch2_folio_reservation_put(c, inode, &res); 966 967 return copied ?: ret; 968 } 969 970 static ssize_t bch2_buffered_write(struct kiocb *iocb, struct iov_iter *iter) 971 { 972 struct file *file = iocb->ki_filp; 973 struct address_space *mapping = file->f_mapping; 974 struct bch_inode_info *inode = file_bch_inode(file); 975 loff_t pos = iocb->ki_pos; 976 ssize_t written = 0; 977 int ret = 0; 978 979 bch2_pagecache_add_get(inode); 980 981 do { 982 unsigned offset = pos & (PAGE_SIZE - 1); 983 unsigned bytes = iov_iter_count(iter); 984 again: 985 /* 986 * Bring in the user page that we will copy from _first_. 987 * Otherwise there's a nasty deadlock on copying from the 988 * same page as we're writing to, without it being marked 989 * up-to-date. 990 * 991 * Not only is this an optimisation, but it is also required 992 * to check that the address is actually valid, when atomic 993 * usercopies are used, below. 994 */ 995 if (unlikely(fault_in_iov_iter_readable(iter, bytes))) { 996 bytes = min_t(unsigned long, iov_iter_count(iter), 997 PAGE_SIZE - offset); 998 999 if (unlikely(fault_in_iov_iter_readable(iter, bytes))) { 1000 ret = -EFAULT; 1001 break; 1002 } 1003 } 1004 1005 if (unlikely(fatal_signal_pending(current))) { 1006 ret = -EINTR; 1007 break; 1008 } 1009 1010 ret = __bch2_buffered_write(inode, mapping, iter, pos, bytes); 1011 if (unlikely(ret < 0)) 1012 break; 1013 1014 cond_resched(); 1015 1016 if (unlikely(ret == 0)) { 1017 /* 1018 * If we were unable to copy any data at all, we must 1019 * fall back to a single segment length write. 1020 * 1021 * If we didn't fallback here, we could livelock 1022 * because not all segments in the iov can be copied at 1023 * once without a pagefault. 1024 */ 1025 bytes = min_t(unsigned long, PAGE_SIZE - offset, 1026 iov_iter_single_seg_count(iter)); 1027 goto again; 1028 } 1029 pos += ret; 1030 written += ret; 1031 ret = 0; 1032 1033 balance_dirty_pages_ratelimited(mapping); 1034 } while (iov_iter_count(iter)); 1035 1036 bch2_pagecache_add_put(inode); 1037 1038 return written ? written : ret; 1039 } 1040 1041 ssize_t bch2_write_iter(struct kiocb *iocb, struct iov_iter *from) 1042 { 1043 struct file *file = iocb->ki_filp; 1044 struct bch_inode_info *inode = file_bch_inode(file); 1045 ssize_t ret; 1046 1047 if (iocb->ki_flags & IOCB_DIRECT) { 1048 ret = bch2_direct_write(iocb, from); 1049 goto out; 1050 } 1051 1052 inode_lock(&inode->v); 1053 1054 ret = generic_write_checks(iocb, from); 1055 if (ret <= 0) 1056 goto unlock; 1057 1058 ret = file_remove_privs(file); 1059 if (ret) 1060 goto unlock; 1061 1062 ret = file_update_time(file); 1063 if (ret) 1064 goto unlock; 1065 1066 ret = bch2_buffered_write(iocb, from); 1067 if (likely(ret > 0)) 1068 iocb->ki_pos += ret; 1069 unlock: 1070 inode_unlock(&inode->v); 1071 1072 if (ret > 0) 1073 ret = generic_write_sync(iocb, ret); 1074 out: 1075 return bch2_err_class(ret); 1076 } 1077 1078 void bch2_fs_fs_io_buffered_exit(struct bch_fs *c) 1079 { 1080 bioset_exit(&c->writepage_bioset); 1081 } 1082 1083 int bch2_fs_fs_io_buffered_init(struct bch_fs *c) 1084 { 1085 if (bioset_init(&c->writepage_bioset, 1086 4, offsetof(struct bch_writepage_io, op.wbio.bio), 1087 BIOSET_NEED_BVECS)) 1088 return -BCH_ERR_ENOMEM_writepage_bioset_init; 1089 1090 return 0; 1091 } 1092 1093 #endif /* NO_BCACHEFS_FS */ 1094