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 page *page = 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 page = find_or_create_page(mapping, file_offset >> PAGE_SHIFT, 87 btrfs_alloc_write_mask(mapping)); 88 if (!page) { 89 ret = -ENOMEM; 90 goto out_unlock; 91 } 92 93 ret = set_page_extent_mapped(page); 94 if (ret < 0) 95 goto out_unlock; 96 97 clear_extent_bit(&inode->io_tree, file_offset, range_end, 98 EXTENT_DELALLOC | EXTENT_DO_ACCOUNTING | EXTENT_DEFRAG, 99 NULL); 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_page(page, offset_in_page(file_offset), data_start, 119 datal); 120 } else { 121 ret = btrfs_decompress(comp_type, data_start, page, 122 offset_in_page(file_offset), 123 inline_size, datal); 124 if (ret) 125 goto out_unlock; 126 flush_dcache_page(page); 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 memzero_page(page, datal, block_size - datal); 143 144 btrfs_folio_set_uptodate(fs_info, page_folio(page), file_offset, block_size); 145 btrfs_folio_clear_checked(fs_info, page_folio(page), file_offset, block_size); 146 btrfs_folio_set_dirty(fs_info, page_folio(page), file_offset, block_size); 147 out_unlock: 148 if (page) { 149 unlock_page(page); 150 put_page(page); 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 inode *dst, 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_fs_info *fs_info = btrfs_sb(dst->i_sb); 178 struct btrfs_root *root = BTRFS_I(dst)->root; 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(BTRFS_I(dst), new_key->offset, 188 inline_data, size, datal, comp_type); 189 goto out; 190 } 191 192 key.objectid = btrfs_ino(BTRFS_I(dst)); 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(BTRFS_I(dst)) && 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(dst) <= 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(dst) > 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, BTRFS_I(dst), &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(BTRFS_I(dst), datal, drop_args.bytes_found); 284 btrfs_set_inode_full_sync(BTRFS_I(dst)); 285 ret = btrfs_inode_set_file_extent_range(BTRFS_I(dst), 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(BTRFS_I(dst), 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 = btrfs_sb(inode->i_sb); 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(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_extent_unlock(struct inode *inode1, u64 loff1, 620 struct inode *inode2, u64 loff2, u64 len) 621 { 622 unlock_extent(&BTRFS_I(inode1)->io_tree, loff1, loff1 + len - 1, NULL); 623 unlock_extent(&BTRFS_I(inode2)->io_tree, loff2, loff2 + len - 1, NULL); 624 } 625 626 static void btrfs_double_extent_lock(struct inode *inode1, u64 loff1, 627 struct inode *inode2, u64 loff2, u64 len) 628 { 629 u64 range1_end = loff1 + len - 1; 630 u64 range2_end = loff2 + len - 1; 631 632 if (inode1 < inode2) { 633 swap(inode1, inode2); 634 swap(loff1, loff2); 635 swap(range1_end, range2_end); 636 } else if (inode1 == inode2 && loff2 < loff1) { 637 swap(loff1, loff2); 638 swap(range1_end, range2_end); 639 } 640 641 lock_extent(&BTRFS_I(inode1)->io_tree, loff1, range1_end, NULL); 642 lock_extent(&BTRFS_I(inode2)->io_tree, loff2, range2_end, NULL); 643 644 btrfs_assert_inode_range_clean(BTRFS_I(inode1), loff1, range1_end); 645 btrfs_assert_inode_range_clean(BTRFS_I(inode2), loff2, range2_end); 646 } 647 648 static void btrfs_double_mmap_lock(struct inode *inode1, struct inode *inode2) 649 { 650 if (inode1 < inode2) 651 swap(inode1, inode2); 652 down_write(&BTRFS_I(inode1)->i_mmap_lock); 653 down_write_nested(&BTRFS_I(inode2)->i_mmap_lock, SINGLE_DEPTH_NESTING); 654 } 655 656 static void btrfs_double_mmap_unlock(struct inode *inode1, struct inode *inode2) 657 { 658 up_write(&BTRFS_I(inode1)->i_mmap_lock); 659 up_write(&BTRFS_I(inode2)->i_mmap_lock); 660 } 661 662 static int btrfs_extent_same_range(struct inode *src, u64 loff, u64 len, 663 struct inode *dst, u64 dst_loff) 664 { 665 struct btrfs_fs_info *fs_info = BTRFS_I(src)->root->fs_info; 666 const u64 bs = fs_info->sb->s_blocksize; 667 int ret; 668 669 /* 670 * Lock destination range to serialize with concurrent readahead() and 671 * source range to serialize with relocation. 672 */ 673 btrfs_double_extent_lock(src, loff, dst, dst_loff, len); 674 ret = btrfs_clone(src, dst, loff, len, ALIGN(len, bs), dst_loff, 1); 675 btrfs_double_extent_unlock(src, loff, dst, dst_loff, len); 676 677 btrfs_btree_balance_dirty(fs_info); 678 679 return ret; 680 } 681 682 static int btrfs_extent_same(struct inode *src, u64 loff, u64 olen, 683 struct inode *dst, u64 dst_loff) 684 { 685 int ret = 0; 686 u64 i, tail_len, chunk_count; 687 struct btrfs_root *root_dst = BTRFS_I(dst)->root; 688 689 spin_lock(&root_dst->root_item_lock); 690 if (root_dst->send_in_progress) { 691 btrfs_warn_rl(root_dst->fs_info, 692 "cannot deduplicate to root %llu while send operations are using it (%d in progress)", 693 root_dst->root_key.objectid, 694 root_dst->send_in_progress); 695 spin_unlock(&root_dst->root_item_lock); 696 return -EAGAIN; 697 } 698 root_dst->dedupe_in_progress++; 699 spin_unlock(&root_dst->root_item_lock); 700 701 tail_len = olen % BTRFS_MAX_DEDUPE_LEN; 702 chunk_count = div_u64(olen, BTRFS_MAX_DEDUPE_LEN); 703 704 for (i = 0; i < chunk_count; i++) { 705 ret = btrfs_extent_same_range(src, loff, BTRFS_MAX_DEDUPE_LEN, 706 dst, dst_loff); 707 if (ret) 708 goto out; 709 710 loff += BTRFS_MAX_DEDUPE_LEN; 711 dst_loff += BTRFS_MAX_DEDUPE_LEN; 712 } 713 714 if (tail_len > 0) 715 ret = btrfs_extent_same_range(src, loff, tail_len, dst, dst_loff); 716 out: 717 spin_lock(&root_dst->root_item_lock); 718 root_dst->dedupe_in_progress--; 719 spin_unlock(&root_dst->root_item_lock); 720 721 return ret; 722 } 723 724 static noinline int btrfs_clone_files(struct file *file, struct file *file_src, 725 u64 off, u64 olen, u64 destoff) 726 { 727 struct inode *inode = file_inode(file); 728 struct inode *src = file_inode(file_src); 729 struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb); 730 int ret; 731 int wb_ret; 732 u64 len = olen; 733 u64 bs = fs_info->sb->s_blocksize; 734 735 /* 736 * VFS's generic_remap_file_range_prep() protects us from cloning the 737 * eof block into the middle of a file, which would result in corruption 738 * if the file size is not blocksize aligned. So we don't need to check 739 * for that case here. 740 */ 741 if (off + len == src->i_size) 742 len = ALIGN(src->i_size, bs) - off; 743 744 if (destoff > inode->i_size) { 745 const u64 wb_start = ALIGN_DOWN(inode->i_size, bs); 746 747 ret = btrfs_cont_expand(BTRFS_I(inode), inode->i_size, destoff); 748 if (ret) 749 return ret; 750 /* 751 * We may have truncated the last block if the inode's size is 752 * not sector size aligned, so we need to wait for writeback to 753 * complete before proceeding further, otherwise we can race 754 * with cloning and attempt to increment a reference to an 755 * extent that no longer exists (writeback completed right after 756 * we found the previous extent covering eof and before we 757 * attempted to increment its reference count). 758 */ 759 ret = btrfs_wait_ordered_range(inode, wb_start, 760 destoff - wb_start); 761 if (ret) 762 return ret; 763 } 764 765 /* 766 * Lock destination range to serialize with concurrent readahead() and 767 * source range to serialize with relocation. 768 */ 769 btrfs_double_extent_lock(src, off, inode, destoff, len); 770 ret = btrfs_clone(src, inode, off, olen, len, destoff, 0); 771 btrfs_double_extent_unlock(src, off, inode, destoff, len); 772 773 /* 774 * We may have copied an inline extent into a page of the destination 775 * range, so wait for writeback to complete before truncating pages 776 * from the page cache. This is a rare case. 777 */ 778 wb_ret = btrfs_wait_ordered_range(inode, destoff, len); 779 ret = ret ? ret : wb_ret; 780 /* 781 * Truncate page cache pages so that future reads will see the cloned 782 * data immediately and not the previous data. 783 */ 784 truncate_inode_pages_range(&inode->i_data, 785 round_down(destoff, PAGE_SIZE), 786 round_up(destoff + len, PAGE_SIZE) - 1); 787 788 btrfs_btree_balance_dirty(fs_info); 789 790 return ret; 791 } 792 793 static int btrfs_remap_file_range_prep(struct file *file_in, loff_t pos_in, 794 struct file *file_out, loff_t pos_out, 795 loff_t *len, unsigned int remap_flags) 796 { 797 struct inode *inode_in = file_inode(file_in); 798 struct inode *inode_out = file_inode(file_out); 799 u64 bs = BTRFS_I(inode_out)->root->fs_info->sb->s_blocksize; 800 u64 wb_len; 801 int ret; 802 803 if (!(remap_flags & REMAP_FILE_DEDUP)) { 804 struct btrfs_root *root_out = BTRFS_I(inode_out)->root; 805 806 if (btrfs_root_readonly(root_out)) 807 return -EROFS; 808 809 ASSERT(inode_in->i_sb == inode_out->i_sb); 810 } 811 812 /* Don't make the dst file partly checksummed */ 813 if ((BTRFS_I(inode_in)->flags & BTRFS_INODE_NODATASUM) != 814 (BTRFS_I(inode_out)->flags & BTRFS_INODE_NODATASUM)) { 815 return -EINVAL; 816 } 817 818 /* 819 * Now that the inodes are locked, we need to start writeback ourselves 820 * and can not rely on the writeback from the VFS's generic helper 821 * generic_remap_file_range_prep() because: 822 * 823 * 1) For compression we must call filemap_fdatawrite_range() range 824 * twice (btrfs_fdatawrite_range() does it for us), and the generic 825 * helper only calls it once; 826 * 827 * 2) filemap_fdatawrite_range(), called by the generic helper only 828 * waits for the writeback to complete, i.e. for IO to be done, and 829 * not for the ordered extents to complete. We need to wait for them 830 * to complete so that new file extent items are in the fs tree. 831 */ 832 if (*len == 0 && !(remap_flags & REMAP_FILE_DEDUP)) 833 wb_len = ALIGN(inode_in->i_size, bs) - ALIGN_DOWN(pos_in, bs); 834 else 835 wb_len = ALIGN(*len, bs); 836 837 /* 838 * Workaround to make sure NOCOW buffered write reach disk as NOCOW. 839 * 840 * Btrfs' back references do not have a block level granularity, they 841 * work at the whole extent level. 842 * NOCOW buffered write without data space reserved may not be able 843 * to fall back to CoW due to lack of data space, thus could cause 844 * data loss. 845 * 846 * Here we take a shortcut by flushing the whole inode, so that all 847 * nocow write should reach disk as nocow before we increase the 848 * reference of the extent. We could do better by only flushing NOCOW 849 * data, but that needs extra accounting. 850 * 851 * Also we don't need to check ASYNC_EXTENT, as async extent will be 852 * CoWed anyway, not affecting nocow part. 853 */ 854 ret = filemap_flush(inode_in->i_mapping); 855 if (ret < 0) 856 return ret; 857 858 ret = btrfs_wait_ordered_range(inode_in, ALIGN_DOWN(pos_in, bs), 859 wb_len); 860 if (ret < 0) 861 return ret; 862 ret = btrfs_wait_ordered_range(inode_out, ALIGN_DOWN(pos_out, bs), 863 wb_len); 864 if (ret < 0) 865 return ret; 866 867 return generic_remap_file_range_prep(file_in, pos_in, file_out, pos_out, 868 len, remap_flags); 869 } 870 871 static bool file_sync_write(const struct file *file) 872 { 873 if (file->f_flags & (__O_SYNC | O_DSYNC)) 874 return true; 875 if (IS_SYNC(file_inode(file))) 876 return true; 877 878 return false; 879 } 880 881 loff_t btrfs_remap_file_range(struct file *src_file, loff_t off, 882 struct file *dst_file, loff_t destoff, loff_t len, 883 unsigned int remap_flags) 884 { 885 struct inode *src_inode = file_inode(src_file); 886 struct inode *dst_inode = file_inode(dst_file); 887 bool same_inode = dst_inode == src_inode; 888 int ret; 889 890 if (remap_flags & ~(REMAP_FILE_DEDUP | REMAP_FILE_ADVISORY)) 891 return -EINVAL; 892 893 if (same_inode) { 894 btrfs_inode_lock(BTRFS_I(src_inode), BTRFS_ILOCK_MMAP); 895 } else { 896 lock_two_nondirectories(src_inode, dst_inode); 897 btrfs_double_mmap_lock(src_inode, dst_inode); 898 } 899 900 ret = btrfs_remap_file_range_prep(src_file, off, dst_file, destoff, 901 &len, remap_flags); 902 if (ret < 0 || len == 0) 903 goto out_unlock; 904 905 if (remap_flags & REMAP_FILE_DEDUP) 906 ret = btrfs_extent_same(src_inode, off, len, dst_inode, destoff); 907 else 908 ret = btrfs_clone_files(dst_file, src_file, off, len, destoff); 909 910 out_unlock: 911 if (same_inode) { 912 btrfs_inode_unlock(BTRFS_I(src_inode), BTRFS_ILOCK_MMAP); 913 } else { 914 btrfs_double_mmap_unlock(src_inode, dst_inode); 915 unlock_two_nondirectories(src_inode, dst_inode); 916 } 917 918 /* 919 * If either the source or the destination file was opened with O_SYNC, 920 * O_DSYNC or has the S_SYNC attribute, fsync both the destination and 921 * source files/ranges, so that after a successful return (0) followed 922 * by a power failure results in the reflinked data to be readable from 923 * both files/ranges. 924 */ 925 if (ret == 0 && len > 0 && 926 (file_sync_write(src_file) || file_sync_write(dst_file))) { 927 ret = btrfs_sync_file(src_file, off, off + len - 1, 0); 928 if (ret == 0) 929 ret = btrfs_sync_file(dst_file, destoff, 930 destoff + len - 1, 0); 931 } 932 933 return ret < 0 ? ret : len; 934 } 935