1 // SPDX-License-Identifier: GPL-2.0 2 3 #include <linux/blkdev.h> 4 #include <linux/iversion.h> 5 #include "ctree.h" 6 #include "fs.h" 7 #include "messages.h" 8 #include "compression.h" 9 #include "delalloc-space.h" 10 #include "disk-io.h" 11 #include "reflink.h" 12 #include "transaction.h" 13 #include "subpage.h" 14 #include "accessors.h" 15 #include "file-item.h" 16 #include "file.h" 17 #include "super.h" 18 19 #define BTRFS_MAX_DEDUPE_LEN SZ_16M 20 21 static int clone_finish_inode_update(struct btrfs_trans_handle *trans, 22 struct inode *inode, 23 u64 endoff, 24 const u64 destoff, 25 const u64 olen, 26 int no_time_update) 27 { 28 int ret; 29 30 inode_inc_iversion(inode); 31 if (!no_time_update) { 32 inode_set_mtime_to_ts(inode, inode_set_ctime_current(inode)); 33 } 34 /* 35 * We round up to the block size at eof when determining which 36 * extents to clone above, but shouldn't round up the file size. 37 */ 38 if (endoff > destoff + olen) 39 endoff = destoff + olen; 40 if (endoff > inode->i_size) { 41 i_size_write(inode, endoff); 42 btrfs_inode_safe_disk_i_size_write(BTRFS_I(inode), 0); 43 } 44 45 ret = btrfs_update_inode(trans, BTRFS_I(inode)); 46 if (ret) { 47 btrfs_abort_transaction(trans, ret); 48 btrfs_end_transaction(trans); 49 goto out; 50 } 51 ret = btrfs_end_transaction(trans); 52 out: 53 return ret; 54 } 55 56 static int copy_inline_to_page(struct btrfs_inode *inode, 57 const u64 file_offset, 58 char *inline_data, 59 const u64 size, 60 const u64 datal, 61 const u8 comp_type) 62 { 63 struct btrfs_fs_info *fs_info = inode->root->fs_info; 64 const u32 block_size = fs_info->sectorsize; 65 const u64 range_end = file_offset + block_size - 1; 66 const size_t inline_size = size - btrfs_file_extent_calc_inline_size(0); 67 char *data_start = inline_data + btrfs_file_extent_calc_inline_size(0); 68 struct extent_changeset *data_reserved = NULL; 69 struct folio *folio = NULL; 70 struct address_space *mapping = inode->vfs_inode.i_mapping; 71 int ret; 72 73 ASSERT(IS_ALIGNED(file_offset, block_size)); 74 75 /* 76 * We have flushed and locked the ranges of the source and destination 77 * inodes, we also have locked the inodes, so we are safe to do a 78 * reservation here. Also we must not do the reservation while holding 79 * a transaction open, otherwise we would deadlock. 80 */ 81 ret = btrfs_delalloc_reserve_space(inode, &data_reserved, file_offset, 82 block_size); 83 if (ret) 84 goto out; 85 86 folio = __filemap_get_folio(mapping, file_offset >> PAGE_SHIFT, 87 FGP_LOCK | FGP_ACCESSED | FGP_CREAT, 88 btrfs_alloc_write_mask(mapping)); 89 if (IS_ERR(folio)) { 90 ret = PTR_ERR(folio); 91 goto out_unlock; 92 } 93 94 ret = set_folio_extent_mapped(folio); 95 if (ret < 0) 96 goto out_unlock; 97 98 btrfs_clear_extent_bits(&inode->io_tree, file_offset, range_end, 99 EXTENT_DELALLOC | EXTENT_DO_ACCOUNTING | EXTENT_DEFRAG); 100 ret = btrfs_set_extent_delalloc(inode, file_offset, range_end, 0, NULL); 101 if (ret) 102 goto out_unlock; 103 104 /* 105 * After dirtying the page our caller will need to start a transaction, 106 * and if we are low on metadata free space, that can cause flushing of 107 * delalloc for all inodes in order to get metadata space released. 108 * However we are holding the range locked for the whole duration of 109 * the clone/dedupe operation, so we may deadlock if that happens and no 110 * other task releases enough space. So mark this inode as not being 111 * possible to flush to avoid such deadlock. We will clear that flag 112 * when we finish cloning all extents, since a transaction is started 113 * after finding each extent to clone. 114 */ 115 set_bit(BTRFS_INODE_NO_DELALLOC_FLUSH, &inode->runtime_flags); 116 117 if (comp_type == BTRFS_COMPRESS_NONE) { 118 memcpy_to_folio(folio, offset_in_folio(folio, file_offset), data_start, 119 datal); 120 } else { 121 ret = btrfs_decompress(comp_type, data_start, folio, 122 offset_in_folio(folio, file_offset), 123 inline_size, datal); 124 if (ret) 125 goto out_unlock; 126 flush_dcache_folio(folio); 127 } 128 129 /* 130 * If our inline data is smaller then the block/page size, then the 131 * remaining of the block/page is equivalent to zeroes. We had something 132 * like the following done: 133 * 134 * $ xfs_io -f -c "pwrite -S 0xab 0 500" file 135 * $ sync # (or fsync) 136 * $ xfs_io -c "falloc 0 4K" file 137 * $ xfs_io -c "pwrite -S 0xcd 4K 4K" 138 * 139 * So what's in the range [500, 4095] corresponds to zeroes. 140 */ 141 if (datal < block_size) 142 folio_zero_range(folio, datal, block_size - datal); 143 144 btrfs_folio_set_uptodate(fs_info, folio, file_offset, block_size); 145 btrfs_folio_clear_checked(fs_info, folio, file_offset, block_size); 146 btrfs_folio_set_dirty(fs_info, folio, file_offset, block_size); 147 out_unlock: 148 if (!IS_ERR(folio)) { 149 folio_unlock(folio); 150 folio_put(folio); 151 } 152 if (ret) 153 btrfs_delalloc_release_space(inode, data_reserved, file_offset, 154 block_size, true); 155 btrfs_delalloc_release_extents(inode, block_size); 156 out: 157 extent_changeset_free(data_reserved); 158 159 return ret; 160 } 161 162 /* 163 * Deal with cloning of inline extents. We try to copy the inline extent from 164 * the source inode to destination inode when possible. When not possible we 165 * copy the inline extent's data into the respective page of the inode. 166 */ 167 static int clone_copy_inline_extent(struct btrfs_inode *inode, 168 struct btrfs_path *path, 169 struct btrfs_key *new_key, 170 const u64 drop_start, 171 const u64 datal, 172 const u64 size, 173 const u8 comp_type, 174 char *inline_data, 175 struct btrfs_trans_handle **trans_out) 176 { 177 struct btrfs_root *root = inode->root; 178 struct btrfs_fs_info *fs_info = root->fs_info; 179 const u64 aligned_end = ALIGN(new_key->offset + datal, 180 fs_info->sectorsize); 181 struct btrfs_trans_handle *trans = NULL; 182 struct btrfs_drop_extents_args drop_args = { 0 }; 183 int ret; 184 struct btrfs_key key; 185 186 if (new_key->offset > 0) { 187 ret = copy_inline_to_page(inode, new_key->offset, 188 inline_data, size, datal, comp_type); 189 goto out; 190 } 191 192 key.objectid = btrfs_ino(inode); 193 key.type = BTRFS_EXTENT_DATA_KEY; 194 key.offset = 0; 195 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0); 196 if (ret < 0) { 197 return ret; 198 } else if (ret > 0) { 199 if (path->slots[0] >= btrfs_header_nritems(path->nodes[0])) { 200 ret = btrfs_next_leaf(root, path); 201 if (ret < 0) 202 return ret; 203 else if (ret > 0) 204 goto copy_inline_extent; 205 } 206 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]); 207 if (key.objectid == btrfs_ino(inode) && 208 key.type == BTRFS_EXTENT_DATA_KEY) { 209 /* 210 * There's an implicit hole at file offset 0, copy the 211 * inline extent's data to the page. 212 */ 213 ASSERT(key.offset > 0); 214 goto copy_to_page; 215 } 216 } else if (i_size_read(&inode->vfs_inode) <= datal) { 217 struct btrfs_file_extent_item *ei; 218 219 ei = btrfs_item_ptr(path->nodes[0], path->slots[0], 220 struct btrfs_file_extent_item); 221 /* 222 * If it's an inline extent replace it with the source inline 223 * extent, otherwise copy the source inline extent data into 224 * the respective page at the destination inode. 225 */ 226 if (btrfs_file_extent_type(path->nodes[0], ei) == 227 BTRFS_FILE_EXTENT_INLINE) 228 goto copy_inline_extent; 229 230 goto copy_to_page; 231 } 232 233 copy_inline_extent: 234 /* 235 * We have no extent items, or we have an extent at offset 0 which may 236 * or may not be inlined. All these cases are dealt the same way. 237 */ 238 if (i_size_read(&inode->vfs_inode) > datal) { 239 /* 240 * At the destination offset 0 we have either a hole, a regular 241 * extent or an inline extent larger then the one we want to 242 * clone. Deal with all these cases by copying the inline extent 243 * data into the respective page at the destination inode. 244 */ 245 goto copy_to_page; 246 } 247 248 /* 249 * Release path before starting a new transaction so we don't hold locks 250 * that would confuse lockdep. 251 */ 252 btrfs_release_path(path); 253 /* 254 * If we end up here it means were copy the inline extent into a leaf 255 * of the destination inode. We know we will drop or adjust at most one 256 * extent item in the destination root. 257 * 258 * 1 unit - adjusting old extent (we may have to split it) 259 * 1 unit - add new extent 260 * 1 unit - inode update 261 */ 262 trans = btrfs_start_transaction(root, 3); 263 if (IS_ERR(trans)) { 264 ret = PTR_ERR(trans); 265 trans = NULL; 266 goto out; 267 } 268 drop_args.path = path; 269 drop_args.start = drop_start; 270 drop_args.end = aligned_end; 271 drop_args.drop_cache = true; 272 ret = btrfs_drop_extents(trans, root, inode, &drop_args); 273 if (ret) 274 goto out; 275 ret = btrfs_insert_empty_item(trans, root, path, new_key, size); 276 if (ret) 277 goto out; 278 279 write_extent_buffer(path->nodes[0], inline_data, 280 btrfs_item_ptr_offset(path->nodes[0], 281 path->slots[0]), 282 size); 283 btrfs_update_inode_bytes(inode, datal, drop_args.bytes_found); 284 btrfs_set_inode_full_sync(inode); 285 ret = btrfs_inode_set_file_extent_range(inode, 0, aligned_end); 286 out: 287 if (!ret && !trans) { 288 /* 289 * No transaction here means we copied the inline extent into a 290 * page of the destination inode. 291 * 292 * 1 unit to update inode item 293 */ 294 trans = btrfs_start_transaction(root, 1); 295 if (IS_ERR(trans)) { 296 ret = PTR_ERR(trans); 297 trans = NULL; 298 } 299 } 300 if (ret && trans) { 301 btrfs_abort_transaction(trans, ret); 302 btrfs_end_transaction(trans); 303 } 304 if (!ret) 305 *trans_out = trans; 306 307 return ret; 308 309 copy_to_page: 310 /* 311 * Release our path because we don't need it anymore and also because 312 * copy_inline_to_page() needs to reserve data and metadata, which may 313 * need to flush delalloc when we are low on available space and 314 * therefore cause a deadlock if writeback of an inline extent needs to 315 * write to the same leaf or an ordered extent completion needs to write 316 * to the same leaf. 317 */ 318 btrfs_release_path(path); 319 320 ret = copy_inline_to_page(inode, new_key->offset, 321 inline_data, size, datal, comp_type); 322 goto out; 323 } 324 325 /* 326 * Clone a range from inode file to another. 327 * 328 * @src: Inode to clone from 329 * @inode: Inode to clone to 330 * @off: Offset within source to start clone from 331 * @olen: Original length, passed by user, of range to clone 332 * @olen_aligned: Block-aligned value of olen 333 * @destoff: Offset within @inode to start clone 334 * @no_time_update: Whether to update mtime/ctime on the target inode 335 */ 336 static int btrfs_clone(struct inode *src, struct inode *inode, 337 const u64 off, const u64 olen, const u64 olen_aligned, 338 const u64 destoff, int no_time_update) 339 { 340 struct btrfs_fs_info *fs_info = inode_to_fs_info(inode); 341 struct btrfs_path *path = NULL; 342 struct extent_buffer *leaf; 343 struct btrfs_trans_handle *trans; 344 char *buf = NULL; 345 struct btrfs_key key; 346 u32 nritems; 347 int slot; 348 int ret; 349 const u64 len = olen_aligned; 350 u64 last_dest_end = destoff; 351 u64 prev_extent_end = off; 352 353 ret = -ENOMEM; 354 buf = kvmalloc(fs_info->nodesize, GFP_KERNEL); 355 if (!buf) 356 return ret; 357 358 path = btrfs_alloc_path(); 359 if (!path) { 360 kvfree(buf); 361 return ret; 362 } 363 364 path->reada = READA_FORWARD; 365 /* Clone data */ 366 key.objectid = btrfs_ino(BTRFS_I(src)); 367 key.type = BTRFS_EXTENT_DATA_KEY; 368 key.offset = off; 369 370 while (1) { 371 struct btrfs_file_extent_item *extent; 372 u64 extent_gen; 373 int type; 374 u32 size; 375 struct btrfs_key new_key; 376 u64 disko = 0, diskl = 0; 377 u64 datao = 0, datal = 0; 378 u8 comp; 379 u64 drop_start; 380 381 /* Note the key will change type as we walk through the tree */ 382 ret = btrfs_search_slot(NULL, BTRFS_I(src)->root, &key, path, 383 0, 0); 384 if (ret < 0) 385 goto out; 386 /* 387 * First search, if no extent item that starts at offset off was 388 * found but the previous item is an extent item, it's possible 389 * it might overlap our target range, therefore process it. 390 */ 391 if (key.offset == off && ret > 0 && path->slots[0] > 0) { 392 btrfs_item_key_to_cpu(path->nodes[0], &key, 393 path->slots[0] - 1); 394 if (key.type == BTRFS_EXTENT_DATA_KEY) 395 path->slots[0]--; 396 } 397 398 nritems = btrfs_header_nritems(path->nodes[0]); 399 process_slot: 400 if (path->slots[0] >= nritems) { 401 ret = btrfs_next_leaf(BTRFS_I(src)->root, path); 402 if (ret < 0) 403 goto out; 404 if (ret > 0) 405 break; 406 nritems = btrfs_header_nritems(path->nodes[0]); 407 } 408 leaf = path->nodes[0]; 409 slot = path->slots[0]; 410 411 btrfs_item_key_to_cpu(leaf, &key, slot); 412 if (key.type > BTRFS_EXTENT_DATA_KEY || 413 key.objectid != btrfs_ino(BTRFS_I(src))) 414 break; 415 416 ASSERT(key.type == BTRFS_EXTENT_DATA_KEY); 417 418 extent = btrfs_item_ptr(leaf, slot, 419 struct btrfs_file_extent_item); 420 extent_gen = btrfs_file_extent_generation(leaf, extent); 421 comp = btrfs_file_extent_compression(leaf, extent); 422 type = btrfs_file_extent_type(leaf, extent); 423 if (type == BTRFS_FILE_EXTENT_REG || 424 type == BTRFS_FILE_EXTENT_PREALLOC) { 425 disko = btrfs_file_extent_disk_bytenr(leaf, extent); 426 diskl = btrfs_file_extent_disk_num_bytes(leaf, extent); 427 datao = btrfs_file_extent_offset(leaf, extent); 428 datal = btrfs_file_extent_num_bytes(leaf, extent); 429 } else if (type == BTRFS_FILE_EXTENT_INLINE) { 430 /* Take upper bound, may be compressed */ 431 datal = btrfs_file_extent_ram_bytes(leaf, extent); 432 } 433 434 /* 435 * The first search might have left us at an extent item that 436 * ends before our target range's start, can happen if we have 437 * holes and NO_HOLES feature enabled. 438 * 439 * Subsequent searches may leave us on a file range we have 440 * processed before - this happens due to a race with ordered 441 * extent completion for a file range that is outside our source 442 * range, but that range was part of a file extent item that 443 * also covered a leading part of our source range. 444 */ 445 if (key.offset + datal <= prev_extent_end) { 446 path->slots[0]++; 447 goto process_slot; 448 } else if (key.offset >= off + len) { 449 break; 450 } 451 452 prev_extent_end = key.offset + datal; 453 size = btrfs_item_size(leaf, slot); 454 read_extent_buffer(leaf, buf, btrfs_item_ptr_offset(leaf, slot), 455 size); 456 457 btrfs_release_path(path); 458 459 memcpy(&new_key, &key, sizeof(new_key)); 460 new_key.objectid = btrfs_ino(BTRFS_I(inode)); 461 if (off <= key.offset) 462 new_key.offset = key.offset + destoff - off; 463 else 464 new_key.offset = destoff; 465 466 /* 467 * Deal with a hole that doesn't have an extent item that 468 * represents it (NO_HOLES feature enabled). 469 * This hole is either in the middle of the cloning range or at 470 * the beginning (fully overlaps it or partially overlaps it). 471 */ 472 if (new_key.offset != last_dest_end) 473 drop_start = last_dest_end; 474 else 475 drop_start = new_key.offset; 476 477 if (type == BTRFS_FILE_EXTENT_REG || 478 type == BTRFS_FILE_EXTENT_PREALLOC) { 479 struct btrfs_replace_extent_info clone_info; 480 481 /* 482 * a | --- range to clone ---| b 483 * | ------------- extent ------------- | 484 */ 485 486 /* Subtract range b */ 487 if (key.offset + datal > off + len) 488 datal = off + len - key.offset; 489 490 /* Subtract range a */ 491 if (off > key.offset) { 492 datao += off - key.offset; 493 datal -= off - key.offset; 494 } 495 496 clone_info.disk_offset = disko; 497 clone_info.disk_len = diskl; 498 clone_info.data_offset = datao; 499 clone_info.data_len = datal; 500 clone_info.file_offset = new_key.offset; 501 clone_info.extent_buf = buf; 502 clone_info.is_new_extent = false; 503 clone_info.update_times = !no_time_update; 504 ret = btrfs_replace_file_extents(BTRFS_I(inode), path, 505 drop_start, new_key.offset + datal - 1, 506 &clone_info, &trans); 507 if (ret) 508 goto out; 509 } else { 510 ASSERT(type == BTRFS_FILE_EXTENT_INLINE); 511 /* 512 * Inline extents always have to start at file offset 0 513 * and can never be bigger then the sector size. We can 514 * never clone only parts of an inline extent, since all 515 * reflink operations must start at a sector size aligned 516 * offset, and the length must be aligned too or end at 517 * the i_size (which implies the whole inlined data). 518 */ 519 ASSERT(key.offset == 0); 520 ASSERT(datal <= fs_info->sectorsize); 521 if (WARN_ON(type != BTRFS_FILE_EXTENT_INLINE) || 522 WARN_ON(key.offset != 0) || 523 WARN_ON(datal > fs_info->sectorsize)) { 524 ret = -EUCLEAN; 525 goto out; 526 } 527 528 ret = clone_copy_inline_extent(BTRFS_I(inode), path, &new_key, 529 drop_start, datal, size, 530 comp, buf, &trans); 531 if (ret) 532 goto out; 533 } 534 535 btrfs_release_path(path); 536 537 /* 538 * Whenever we share an extent we update the last_reflink_trans 539 * of each inode to the current transaction. This is needed to 540 * make sure fsync does not log multiple checksum items with 541 * overlapping ranges (because some extent items might refer 542 * only to sections of the original extent). For the destination 543 * inode we do this regardless of the generation of the extents 544 * or even if they are inline extents or explicit holes, to make 545 * sure a full fsync does not skip them. For the source inode, 546 * we only need to update last_reflink_trans in case it's a new 547 * extent that is not a hole or an inline extent, to deal with 548 * the checksums problem on fsync. 549 */ 550 if (extent_gen == trans->transid && disko > 0) 551 BTRFS_I(src)->last_reflink_trans = trans->transid; 552 553 BTRFS_I(inode)->last_reflink_trans = trans->transid; 554 555 last_dest_end = ALIGN(new_key.offset + datal, 556 fs_info->sectorsize); 557 ret = clone_finish_inode_update(trans, inode, last_dest_end, 558 destoff, olen, no_time_update); 559 if (ret) 560 goto out; 561 if (new_key.offset + datal >= destoff + len) 562 break; 563 564 btrfs_release_path(path); 565 key.offset = prev_extent_end; 566 567 if (fatal_signal_pending(current)) { 568 ret = -EINTR; 569 goto out; 570 } 571 572 cond_resched(); 573 } 574 ret = 0; 575 576 if (last_dest_end < destoff + len) { 577 /* 578 * We have an implicit hole that fully or partially overlaps our 579 * cloning range at its end. This means that we either have the 580 * NO_HOLES feature enabled or the implicit hole happened due to 581 * mixing buffered and direct IO writes against this file. 582 */ 583 btrfs_release_path(path); 584 585 /* 586 * When using NO_HOLES and we are cloning a range that covers 587 * only a hole (no extents) into a range beyond the current 588 * i_size, punching a hole in the target range will not create 589 * an extent map defining a hole, because the range starts at or 590 * beyond current i_size. If the file previously had an i_size 591 * greater than the new i_size set by this clone operation, we 592 * need to make sure the next fsync is a full fsync, so that it 593 * detects and logs a hole covering a range from the current 594 * i_size to the new i_size. If the clone range covers extents, 595 * besides a hole, then we know the full sync flag was already 596 * set by previous calls to btrfs_replace_file_extents() that 597 * replaced file extent items. 598 */ 599 if (last_dest_end >= i_size_read(inode)) 600 btrfs_set_inode_full_sync(BTRFS_I(inode)); 601 602 ret = btrfs_replace_file_extents(BTRFS_I(inode), path, 603 last_dest_end, destoff + len - 1, NULL, &trans); 604 if (ret) 605 goto out; 606 607 ret = clone_finish_inode_update(trans, inode, destoff + len, 608 destoff, olen, no_time_update); 609 } 610 611 out: 612 btrfs_free_path(path); 613 kvfree(buf); 614 clear_bit(BTRFS_INODE_NO_DELALLOC_FLUSH, &BTRFS_I(inode)->runtime_flags); 615 616 return ret; 617 } 618 619 static void btrfs_double_mmap_lock(struct btrfs_inode *inode1, struct btrfs_inode *inode2) 620 { 621 if (inode1 < inode2) 622 swap(inode1, inode2); 623 down_write(&inode1->i_mmap_lock); 624 down_write_nested(&inode2->i_mmap_lock, SINGLE_DEPTH_NESTING); 625 } 626 627 static void btrfs_double_mmap_unlock(struct btrfs_inode *inode1, struct btrfs_inode *inode2) 628 { 629 up_write(&inode1->i_mmap_lock); 630 up_write(&inode2->i_mmap_lock); 631 } 632 633 static int btrfs_extent_same_range(struct btrfs_inode *src, u64 loff, u64 len, 634 struct btrfs_inode *dst, u64 dst_loff) 635 { 636 const u64 end = dst_loff + len - 1; 637 struct extent_state *cached_state = NULL; 638 struct btrfs_fs_info *fs_info = src->root->fs_info; 639 const u64 bs = fs_info->sectorsize; 640 int ret; 641 642 /* 643 * Lock destination range to serialize with concurrent readahead(), and 644 * we are safe from concurrency with relocation of source extents 645 * because we have already locked the inode's i_mmap_lock in exclusive 646 * mode. 647 */ 648 btrfs_lock_extent(&dst->io_tree, dst_loff, end, &cached_state); 649 ret = btrfs_clone(&src->vfs_inode, &dst->vfs_inode, loff, len, 650 ALIGN(len, bs), dst_loff, 1); 651 btrfs_unlock_extent(&dst->io_tree, dst_loff, end, &cached_state); 652 653 btrfs_btree_balance_dirty(fs_info); 654 655 return ret; 656 } 657 658 static int btrfs_extent_same(struct inode *src, u64 loff, u64 olen, 659 struct inode *dst, u64 dst_loff) 660 { 661 int ret = 0; 662 u64 i, tail_len, chunk_count; 663 struct btrfs_root *root_dst = BTRFS_I(dst)->root; 664 665 spin_lock(&root_dst->root_item_lock); 666 if (root_dst->send_in_progress) { 667 btrfs_warn_rl(root_dst->fs_info, 668 "cannot deduplicate to root %llu while send operations are using it (%d in progress)", 669 btrfs_root_id(root_dst), 670 root_dst->send_in_progress); 671 spin_unlock(&root_dst->root_item_lock); 672 return -EAGAIN; 673 } 674 root_dst->dedupe_in_progress++; 675 spin_unlock(&root_dst->root_item_lock); 676 677 tail_len = olen % BTRFS_MAX_DEDUPE_LEN; 678 chunk_count = div_u64(olen, BTRFS_MAX_DEDUPE_LEN); 679 680 for (i = 0; i < chunk_count; i++) { 681 ret = btrfs_extent_same_range(BTRFS_I(src), loff, BTRFS_MAX_DEDUPE_LEN, 682 BTRFS_I(dst), dst_loff); 683 if (ret) 684 goto out; 685 686 loff += BTRFS_MAX_DEDUPE_LEN; 687 dst_loff += BTRFS_MAX_DEDUPE_LEN; 688 } 689 690 if (tail_len > 0) 691 ret = btrfs_extent_same_range(BTRFS_I(src), loff, tail_len, 692 BTRFS_I(dst), dst_loff); 693 out: 694 spin_lock(&root_dst->root_item_lock); 695 root_dst->dedupe_in_progress--; 696 spin_unlock(&root_dst->root_item_lock); 697 698 return ret; 699 } 700 701 static noinline int btrfs_clone_files(struct file *file, struct file *file_src, 702 u64 off, u64 olen, u64 destoff) 703 { 704 struct extent_state *cached_state = NULL; 705 struct inode *inode = file_inode(file); 706 struct inode *src = file_inode(file_src); 707 struct btrfs_fs_info *fs_info = inode_to_fs_info(inode); 708 int ret; 709 int wb_ret; 710 u64 len = olen; 711 u64 bs = fs_info->sectorsize; 712 u64 end; 713 714 /* 715 * VFS's generic_remap_file_range_prep() protects us from cloning the 716 * eof block into the middle of a file, which would result in corruption 717 * if the file size is not blocksize aligned. So we don't need to check 718 * for that case here. 719 */ 720 if (off + len == src->i_size) 721 len = ALIGN(src->i_size, bs) - off; 722 723 if (destoff > inode->i_size) { 724 const u64 wb_start = ALIGN_DOWN(inode->i_size, bs); 725 726 ret = btrfs_cont_expand(BTRFS_I(inode), inode->i_size, destoff); 727 if (ret) 728 return ret; 729 /* 730 * We may have truncated the last block if the inode's size is 731 * not sector size aligned, so we need to wait for writeback to 732 * complete before proceeding further, otherwise we can race 733 * with cloning and attempt to increment a reference to an 734 * extent that no longer exists (writeback completed right after 735 * we found the previous extent covering eof and before we 736 * attempted to increment its reference count). 737 */ 738 ret = btrfs_wait_ordered_range(BTRFS_I(inode), wb_start, 739 destoff - wb_start); 740 if (ret) 741 return ret; 742 } 743 744 /* 745 * Lock destination range to serialize with concurrent readahead(), and 746 * we are safe from concurrency with relocation of source extents 747 * because we have already locked the inode's i_mmap_lock in exclusive 748 * mode. 749 */ 750 end = destoff + len - 1; 751 btrfs_lock_extent(&BTRFS_I(inode)->io_tree, destoff, end, &cached_state); 752 ret = btrfs_clone(src, inode, off, olen, len, destoff, 0); 753 btrfs_unlock_extent(&BTRFS_I(inode)->io_tree, destoff, end, &cached_state); 754 755 /* 756 * We may have copied an inline extent into a page of the destination 757 * range, so wait for writeback to complete before truncating pages 758 * from the page cache. This is a rare case. 759 */ 760 wb_ret = btrfs_wait_ordered_range(BTRFS_I(inode), destoff, len); 761 ret = ret ? ret : wb_ret; 762 /* 763 * Truncate page cache pages so that future reads will see the cloned 764 * data immediately and not the previous data. 765 */ 766 truncate_inode_pages_range(&inode->i_data, 767 round_down(destoff, PAGE_SIZE), 768 round_up(destoff + len, PAGE_SIZE) - 1); 769 770 btrfs_btree_balance_dirty(fs_info); 771 772 return ret; 773 } 774 775 static int btrfs_remap_file_range_prep(struct file *file_in, loff_t pos_in, 776 struct file *file_out, loff_t pos_out, 777 loff_t *len, unsigned int remap_flags) 778 { 779 struct btrfs_inode *inode_in = BTRFS_I(file_inode(file_in)); 780 struct btrfs_inode *inode_out = BTRFS_I(file_inode(file_out)); 781 u64 bs = inode_out->root->fs_info->sectorsize; 782 u64 wb_len; 783 int ret; 784 785 if (!(remap_flags & REMAP_FILE_DEDUP)) { 786 struct btrfs_root *root_out = inode_out->root; 787 788 if (btrfs_root_readonly(root_out)) 789 return -EROFS; 790 791 ASSERT(inode_in->vfs_inode.i_sb == inode_out->vfs_inode.i_sb); 792 } 793 794 /* Don't make the dst file partly checksummed */ 795 if ((inode_in->flags & BTRFS_INODE_NODATASUM) != 796 (inode_out->flags & BTRFS_INODE_NODATASUM)) { 797 return -EINVAL; 798 } 799 800 /* 801 * Now that the inodes are locked, we need to start writeback ourselves 802 * and can not rely on the writeback from the VFS's generic helper 803 * generic_remap_file_range_prep() because: 804 * 805 * 1) For compression we must call filemap_fdatawrite_range() range 806 * twice (btrfs_fdatawrite_range() does it for us), and the generic 807 * helper only calls it once; 808 * 809 * 2) filemap_fdatawrite_range(), called by the generic helper only 810 * waits for the writeback to complete, i.e. for IO to be done, and 811 * not for the ordered extents to complete. We need to wait for them 812 * to complete so that new file extent items are in the fs tree. 813 */ 814 if (*len == 0 && !(remap_flags & REMAP_FILE_DEDUP)) 815 wb_len = ALIGN(inode_in->vfs_inode.i_size, bs) - ALIGN_DOWN(pos_in, bs); 816 else 817 wb_len = ALIGN(*len, bs); 818 819 /* 820 * Workaround to make sure NOCOW buffered write reach disk as NOCOW. 821 * 822 * Btrfs' back references do not have a block level granularity, they 823 * work at the whole extent level. 824 * NOCOW buffered write without data space reserved may not be able 825 * to fall back to CoW due to lack of data space, thus could cause 826 * data loss. 827 * 828 * Here we take a shortcut by flushing the whole inode, so that all 829 * nocow write should reach disk as nocow before we increase the 830 * reference of the extent. We could do better by only flushing NOCOW 831 * data, but that needs extra accounting. 832 * 833 * Also we don't need to check ASYNC_EXTENT, as async extent will be 834 * CoWed anyway, not affecting nocow part. 835 */ 836 ret = filemap_flush(inode_in->vfs_inode.i_mapping); 837 if (ret < 0) 838 return ret; 839 840 ret = btrfs_wait_ordered_range(inode_in, ALIGN_DOWN(pos_in, bs), wb_len); 841 if (ret < 0) 842 return ret; 843 ret = btrfs_wait_ordered_range(inode_out, ALIGN_DOWN(pos_out, bs), wb_len); 844 if (ret < 0) 845 return ret; 846 847 return generic_remap_file_range_prep(file_in, pos_in, file_out, pos_out, 848 len, remap_flags); 849 } 850 851 static bool file_sync_write(const struct file *file) 852 { 853 if (file->f_flags & (__O_SYNC | O_DSYNC)) 854 return true; 855 if (IS_SYNC(file_inode(file))) 856 return true; 857 858 return false; 859 } 860 861 loff_t btrfs_remap_file_range(struct file *src_file, loff_t off, 862 struct file *dst_file, loff_t destoff, loff_t len, 863 unsigned int remap_flags) 864 { 865 struct btrfs_inode *src_inode = BTRFS_I(file_inode(src_file)); 866 struct btrfs_inode *dst_inode = BTRFS_I(file_inode(dst_file)); 867 bool same_inode = dst_inode == src_inode; 868 int ret; 869 870 if (remap_flags & ~(REMAP_FILE_DEDUP | REMAP_FILE_ADVISORY)) 871 return -EINVAL; 872 873 if (same_inode) { 874 btrfs_inode_lock(src_inode, BTRFS_ILOCK_MMAP); 875 } else { 876 lock_two_nondirectories(&src_inode->vfs_inode, &dst_inode->vfs_inode); 877 btrfs_double_mmap_lock(src_inode, dst_inode); 878 } 879 880 ret = btrfs_remap_file_range_prep(src_file, off, dst_file, destoff, 881 &len, remap_flags); 882 if (ret < 0 || len == 0) 883 goto out_unlock; 884 885 if (remap_flags & REMAP_FILE_DEDUP) 886 ret = btrfs_extent_same(&src_inode->vfs_inode, off, len, 887 &dst_inode->vfs_inode, destoff); 888 else 889 ret = btrfs_clone_files(dst_file, src_file, off, len, destoff); 890 891 out_unlock: 892 if (same_inode) { 893 btrfs_inode_unlock(src_inode, BTRFS_ILOCK_MMAP); 894 } else { 895 btrfs_double_mmap_unlock(src_inode, dst_inode); 896 unlock_two_nondirectories(&src_inode->vfs_inode, 897 &dst_inode->vfs_inode); 898 } 899 900 /* 901 * If either the source or the destination file was opened with O_SYNC, 902 * O_DSYNC or has the S_SYNC attribute, fsync both the destination and 903 * source files/ranges, so that after a successful return (0) followed 904 * by a power failure results in the reflinked data to be readable from 905 * both files/ranges. 906 */ 907 if (ret == 0 && len > 0 && 908 (file_sync_write(src_file) || file_sync_write(dst_file))) { 909 ret = btrfs_sync_file(src_file, off, off + len - 1, 0); 910 if (ret == 0) 911 ret = btrfs_sync_file(dst_file, destoff, 912 destoff + len - 1, 0); 913 } 914 915 return ret < 0 ? ret : len; 916 } 917