1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Copyright (C) 2007 Oracle. All rights reserved. 4 */ 5 6 #include <linux/bio.h> 7 #include <linux/slab.h> 8 #include <linux/pagemap.h> 9 #include <linux/highmem.h> 10 #include <linux/sched/mm.h> 11 #include "ctree.h" 12 #include "disk-io.h" 13 #include "transaction.h" 14 #include "volumes.h" 15 #include "print-tree.h" 16 #include "compression.h" 17 18 #define __MAX_CSUM_ITEMS(r, size) ((unsigned long)(((BTRFS_LEAF_DATA_SIZE(r) - \ 19 sizeof(struct btrfs_item) * 2) / \ 20 size) - 1)) 21 22 #define MAX_CSUM_ITEMS(r, size) (min_t(u32, __MAX_CSUM_ITEMS(r, size), \ 23 PAGE_SIZE)) 24 25 #define MAX_ORDERED_SUM_BYTES(fs_info) ((PAGE_SIZE - \ 26 sizeof(struct btrfs_ordered_sum)) / \ 27 sizeof(u32) * (fs_info)->sectorsize) 28 29 int btrfs_insert_file_extent(struct btrfs_trans_handle *trans, 30 struct btrfs_root *root, 31 u64 objectid, u64 pos, 32 u64 disk_offset, u64 disk_num_bytes, 33 u64 num_bytes, u64 offset, u64 ram_bytes, 34 u8 compression, u8 encryption, u16 other_encoding) 35 { 36 int ret = 0; 37 struct btrfs_file_extent_item *item; 38 struct btrfs_key file_key; 39 struct btrfs_path *path; 40 struct extent_buffer *leaf; 41 42 path = btrfs_alloc_path(); 43 if (!path) 44 return -ENOMEM; 45 file_key.objectid = objectid; 46 file_key.offset = pos; 47 file_key.type = BTRFS_EXTENT_DATA_KEY; 48 49 path->leave_spinning = 1; 50 ret = btrfs_insert_empty_item(trans, root, path, &file_key, 51 sizeof(*item)); 52 if (ret < 0) 53 goto out; 54 BUG_ON(ret); /* Can't happen */ 55 leaf = path->nodes[0]; 56 item = btrfs_item_ptr(leaf, path->slots[0], 57 struct btrfs_file_extent_item); 58 btrfs_set_file_extent_disk_bytenr(leaf, item, disk_offset); 59 btrfs_set_file_extent_disk_num_bytes(leaf, item, disk_num_bytes); 60 btrfs_set_file_extent_offset(leaf, item, offset); 61 btrfs_set_file_extent_num_bytes(leaf, item, num_bytes); 62 btrfs_set_file_extent_ram_bytes(leaf, item, ram_bytes); 63 btrfs_set_file_extent_generation(leaf, item, trans->transid); 64 btrfs_set_file_extent_type(leaf, item, BTRFS_FILE_EXTENT_REG); 65 btrfs_set_file_extent_compression(leaf, item, compression); 66 btrfs_set_file_extent_encryption(leaf, item, encryption); 67 btrfs_set_file_extent_other_encoding(leaf, item, other_encoding); 68 69 btrfs_mark_buffer_dirty(leaf); 70 out: 71 btrfs_free_path(path); 72 return ret; 73 } 74 75 static struct btrfs_csum_item * 76 btrfs_lookup_csum(struct btrfs_trans_handle *trans, 77 struct btrfs_root *root, 78 struct btrfs_path *path, 79 u64 bytenr, int cow) 80 { 81 struct btrfs_fs_info *fs_info = root->fs_info; 82 int ret; 83 struct btrfs_key file_key; 84 struct btrfs_key found_key; 85 struct btrfs_csum_item *item; 86 struct extent_buffer *leaf; 87 u64 csum_offset = 0; 88 u16 csum_size = btrfs_super_csum_size(fs_info->super_copy); 89 int csums_in_item; 90 91 file_key.objectid = BTRFS_EXTENT_CSUM_OBJECTID; 92 file_key.offset = bytenr; 93 file_key.type = BTRFS_EXTENT_CSUM_KEY; 94 ret = btrfs_search_slot(trans, root, &file_key, path, 0, cow); 95 if (ret < 0) 96 goto fail; 97 leaf = path->nodes[0]; 98 if (ret > 0) { 99 ret = 1; 100 if (path->slots[0] == 0) 101 goto fail; 102 path->slots[0]--; 103 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]); 104 if (found_key.type != BTRFS_EXTENT_CSUM_KEY) 105 goto fail; 106 107 csum_offset = (bytenr - found_key.offset) >> 108 fs_info->sb->s_blocksize_bits; 109 csums_in_item = btrfs_item_size_nr(leaf, path->slots[0]); 110 csums_in_item /= csum_size; 111 112 if (csum_offset == csums_in_item) { 113 ret = -EFBIG; 114 goto fail; 115 } else if (csum_offset > csums_in_item) { 116 goto fail; 117 } 118 } 119 item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_csum_item); 120 item = (struct btrfs_csum_item *)((unsigned char *)item + 121 csum_offset * csum_size); 122 return item; 123 fail: 124 if (ret > 0) 125 ret = -ENOENT; 126 return ERR_PTR(ret); 127 } 128 129 int btrfs_lookup_file_extent(struct btrfs_trans_handle *trans, 130 struct btrfs_root *root, 131 struct btrfs_path *path, u64 objectid, 132 u64 offset, int mod) 133 { 134 int ret; 135 struct btrfs_key file_key; 136 int ins_len = mod < 0 ? -1 : 0; 137 int cow = mod != 0; 138 139 file_key.objectid = objectid; 140 file_key.offset = offset; 141 file_key.type = BTRFS_EXTENT_DATA_KEY; 142 ret = btrfs_search_slot(trans, root, &file_key, path, ins_len, cow); 143 return ret; 144 } 145 146 static blk_status_t __btrfs_lookup_bio_sums(struct inode *inode, struct bio *bio, 147 u64 logical_offset, u32 *dst, int dio) 148 { 149 struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb); 150 struct bio_vec bvec; 151 struct bvec_iter iter; 152 struct btrfs_io_bio *btrfs_bio = btrfs_io_bio(bio); 153 struct btrfs_csum_item *item = NULL; 154 struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree; 155 struct btrfs_path *path; 156 u8 *csum; 157 u64 offset = 0; 158 u64 item_start_offset = 0; 159 u64 item_last_offset = 0; 160 u64 disk_bytenr; 161 u64 page_bytes_left; 162 u32 diff; 163 int nblocks; 164 int count = 0; 165 u16 csum_size = btrfs_super_csum_size(fs_info->super_copy); 166 167 path = btrfs_alloc_path(); 168 if (!path) 169 return BLK_STS_RESOURCE; 170 171 nblocks = bio->bi_iter.bi_size >> inode->i_sb->s_blocksize_bits; 172 if (!dst) { 173 if (nblocks * csum_size > BTRFS_BIO_INLINE_CSUM_SIZE) { 174 btrfs_bio->csum = kmalloc_array(nblocks, csum_size, 175 GFP_NOFS); 176 if (!btrfs_bio->csum) { 177 btrfs_free_path(path); 178 return BLK_STS_RESOURCE; 179 } 180 } else { 181 btrfs_bio->csum = btrfs_bio->csum_inline; 182 } 183 csum = btrfs_bio->csum; 184 } else { 185 csum = (u8 *)dst; 186 } 187 188 if (bio->bi_iter.bi_size > PAGE_SIZE * 8) 189 path->reada = READA_FORWARD; 190 191 /* 192 * the free space stuff is only read when it hasn't been 193 * updated in the current transaction. So, we can safely 194 * read from the commit root and sidestep a nasty deadlock 195 * between reading the free space cache and updating the csum tree. 196 */ 197 if (btrfs_is_free_space_inode(BTRFS_I(inode))) { 198 path->search_commit_root = 1; 199 path->skip_locking = 1; 200 } 201 202 disk_bytenr = (u64)bio->bi_iter.bi_sector << 9; 203 if (dio) 204 offset = logical_offset; 205 206 bio_for_each_segment(bvec, bio, iter) { 207 page_bytes_left = bvec.bv_len; 208 if (count) 209 goto next; 210 211 if (!dio) 212 offset = page_offset(bvec.bv_page) + bvec.bv_offset; 213 count = btrfs_find_ordered_sum(inode, offset, disk_bytenr, 214 (u32 *)csum, nblocks); 215 if (count) 216 goto found; 217 218 if (!item || disk_bytenr < item_start_offset || 219 disk_bytenr >= item_last_offset) { 220 struct btrfs_key found_key; 221 u32 item_size; 222 223 if (item) 224 btrfs_release_path(path); 225 item = btrfs_lookup_csum(NULL, fs_info->csum_root, 226 path, disk_bytenr, 0); 227 if (IS_ERR(item)) { 228 count = 1; 229 memset(csum, 0, csum_size); 230 if (BTRFS_I(inode)->root->root_key.objectid == 231 BTRFS_DATA_RELOC_TREE_OBJECTID) { 232 set_extent_bits(io_tree, offset, 233 offset + fs_info->sectorsize - 1, 234 EXTENT_NODATASUM); 235 } else { 236 btrfs_info_rl(fs_info, 237 "no csum found for inode %llu start %llu", 238 btrfs_ino(BTRFS_I(inode)), offset); 239 } 240 item = NULL; 241 btrfs_release_path(path); 242 goto found; 243 } 244 btrfs_item_key_to_cpu(path->nodes[0], &found_key, 245 path->slots[0]); 246 247 item_start_offset = found_key.offset; 248 item_size = btrfs_item_size_nr(path->nodes[0], 249 path->slots[0]); 250 item_last_offset = item_start_offset + 251 (item_size / csum_size) * 252 fs_info->sectorsize; 253 item = btrfs_item_ptr(path->nodes[0], path->slots[0], 254 struct btrfs_csum_item); 255 } 256 /* 257 * this byte range must be able to fit inside 258 * a single leaf so it will also fit inside a u32 259 */ 260 diff = disk_bytenr - item_start_offset; 261 diff = diff / fs_info->sectorsize; 262 diff = diff * csum_size; 263 count = min_t(int, nblocks, (item_last_offset - disk_bytenr) >> 264 inode->i_sb->s_blocksize_bits); 265 read_extent_buffer(path->nodes[0], csum, 266 ((unsigned long)item) + diff, 267 csum_size * count); 268 found: 269 csum += count * csum_size; 270 nblocks -= count; 271 next: 272 while (count--) { 273 disk_bytenr += fs_info->sectorsize; 274 offset += fs_info->sectorsize; 275 page_bytes_left -= fs_info->sectorsize; 276 if (!page_bytes_left) 277 break; /* move to next bio */ 278 } 279 } 280 281 WARN_ON_ONCE(count); 282 btrfs_free_path(path); 283 return 0; 284 } 285 286 blk_status_t btrfs_lookup_bio_sums(struct inode *inode, struct bio *bio, u32 *dst) 287 { 288 return __btrfs_lookup_bio_sums(inode, bio, 0, dst, 0); 289 } 290 291 blk_status_t btrfs_lookup_bio_sums_dio(struct inode *inode, struct bio *bio, u64 offset) 292 { 293 return __btrfs_lookup_bio_sums(inode, bio, offset, NULL, 1); 294 } 295 296 int btrfs_lookup_csums_range(struct btrfs_root *root, u64 start, u64 end, 297 struct list_head *list, int search_commit) 298 { 299 struct btrfs_fs_info *fs_info = root->fs_info; 300 struct btrfs_key key; 301 struct btrfs_path *path; 302 struct extent_buffer *leaf; 303 struct btrfs_ordered_sum *sums; 304 struct btrfs_csum_item *item; 305 LIST_HEAD(tmplist); 306 unsigned long offset; 307 int ret; 308 size_t size; 309 u64 csum_end; 310 u16 csum_size = btrfs_super_csum_size(fs_info->super_copy); 311 312 ASSERT(IS_ALIGNED(start, fs_info->sectorsize) && 313 IS_ALIGNED(end + 1, fs_info->sectorsize)); 314 315 path = btrfs_alloc_path(); 316 if (!path) 317 return -ENOMEM; 318 319 if (search_commit) { 320 path->skip_locking = 1; 321 path->reada = READA_FORWARD; 322 path->search_commit_root = 1; 323 } 324 325 key.objectid = BTRFS_EXTENT_CSUM_OBJECTID; 326 key.offset = start; 327 key.type = BTRFS_EXTENT_CSUM_KEY; 328 329 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0); 330 if (ret < 0) 331 goto fail; 332 if (ret > 0 && path->slots[0] > 0) { 333 leaf = path->nodes[0]; 334 btrfs_item_key_to_cpu(leaf, &key, path->slots[0] - 1); 335 if (key.objectid == BTRFS_EXTENT_CSUM_OBJECTID && 336 key.type == BTRFS_EXTENT_CSUM_KEY) { 337 offset = (start - key.offset) >> 338 fs_info->sb->s_blocksize_bits; 339 if (offset * csum_size < 340 btrfs_item_size_nr(leaf, path->slots[0] - 1)) 341 path->slots[0]--; 342 } 343 } 344 345 while (start <= end) { 346 leaf = path->nodes[0]; 347 if (path->slots[0] >= btrfs_header_nritems(leaf)) { 348 ret = btrfs_next_leaf(root, path); 349 if (ret < 0) 350 goto fail; 351 if (ret > 0) 352 break; 353 leaf = path->nodes[0]; 354 } 355 356 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]); 357 if (key.objectid != BTRFS_EXTENT_CSUM_OBJECTID || 358 key.type != BTRFS_EXTENT_CSUM_KEY || 359 key.offset > end) 360 break; 361 362 if (key.offset > start) 363 start = key.offset; 364 365 size = btrfs_item_size_nr(leaf, path->slots[0]); 366 csum_end = key.offset + (size / csum_size) * fs_info->sectorsize; 367 if (csum_end <= start) { 368 path->slots[0]++; 369 continue; 370 } 371 372 csum_end = min(csum_end, end + 1); 373 item = btrfs_item_ptr(path->nodes[0], path->slots[0], 374 struct btrfs_csum_item); 375 while (start < csum_end) { 376 size = min_t(size_t, csum_end - start, 377 MAX_ORDERED_SUM_BYTES(fs_info)); 378 sums = kzalloc(btrfs_ordered_sum_size(fs_info, size), 379 GFP_NOFS); 380 if (!sums) { 381 ret = -ENOMEM; 382 goto fail; 383 } 384 385 sums->bytenr = start; 386 sums->len = (int)size; 387 388 offset = (start - key.offset) >> 389 fs_info->sb->s_blocksize_bits; 390 offset *= csum_size; 391 size >>= fs_info->sb->s_blocksize_bits; 392 393 read_extent_buffer(path->nodes[0], 394 sums->sums, 395 ((unsigned long)item) + offset, 396 csum_size * size); 397 398 start += fs_info->sectorsize * size; 399 list_add_tail(&sums->list, &tmplist); 400 } 401 path->slots[0]++; 402 } 403 ret = 0; 404 fail: 405 while (ret < 0 && !list_empty(&tmplist)) { 406 sums = list_entry(tmplist.next, struct btrfs_ordered_sum, list); 407 list_del(&sums->list); 408 kfree(sums); 409 } 410 list_splice_tail(&tmplist, list); 411 412 btrfs_free_path(path); 413 return ret; 414 } 415 416 /* 417 * btrfs_csum_one_bio - Calculates checksums of the data contained inside a bio 418 * @inode: Owner of the data inside the bio 419 * @bio: Contains the data to be checksummed 420 * @file_start: offset in file this bio begins to describe 421 * @contig: Boolean. If true/1 means all bio vecs in this bio are 422 * contiguous and they begin at @file_start in the file. False/0 423 * means this bio can contains potentially discontigous bio vecs 424 * so the logical offset of each should be calculated separately. 425 */ 426 blk_status_t btrfs_csum_one_bio(struct inode *inode, struct bio *bio, 427 u64 file_start, int contig) 428 { 429 struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb); 430 struct btrfs_ordered_sum *sums; 431 struct btrfs_ordered_extent *ordered = NULL; 432 char *data; 433 struct bvec_iter iter; 434 struct bio_vec bvec; 435 int index; 436 int nr_sectors; 437 unsigned long total_bytes = 0; 438 unsigned long this_sum_bytes = 0; 439 int i; 440 u64 offset; 441 unsigned nofs_flag; 442 443 nofs_flag = memalloc_nofs_save(); 444 sums = kvzalloc(btrfs_ordered_sum_size(fs_info, bio->bi_iter.bi_size), 445 GFP_KERNEL); 446 memalloc_nofs_restore(nofs_flag); 447 448 if (!sums) 449 return BLK_STS_RESOURCE; 450 451 sums->len = bio->bi_iter.bi_size; 452 INIT_LIST_HEAD(&sums->list); 453 454 if (contig) 455 offset = file_start; 456 else 457 offset = 0; /* shut up gcc */ 458 459 sums->bytenr = (u64)bio->bi_iter.bi_sector << 9; 460 index = 0; 461 462 bio_for_each_segment(bvec, bio, iter) { 463 if (!contig) 464 offset = page_offset(bvec.bv_page) + bvec.bv_offset; 465 466 if (!ordered) { 467 ordered = btrfs_lookup_ordered_extent(inode, offset); 468 BUG_ON(!ordered); /* Logic error */ 469 } 470 471 nr_sectors = BTRFS_BYTES_TO_BLKS(fs_info, 472 bvec.bv_len + fs_info->sectorsize 473 - 1); 474 475 for (i = 0; i < nr_sectors; i++) { 476 if (offset >= ordered->file_offset + ordered->len || 477 offset < ordered->file_offset) { 478 unsigned long bytes_left; 479 480 sums->len = this_sum_bytes; 481 this_sum_bytes = 0; 482 btrfs_add_ordered_sum(ordered, sums); 483 btrfs_put_ordered_extent(ordered); 484 485 bytes_left = bio->bi_iter.bi_size - total_bytes; 486 487 nofs_flag = memalloc_nofs_save(); 488 sums = kvzalloc(btrfs_ordered_sum_size(fs_info, 489 bytes_left), GFP_KERNEL); 490 memalloc_nofs_restore(nofs_flag); 491 BUG_ON(!sums); /* -ENOMEM */ 492 sums->len = bytes_left; 493 ordered = btrfs_lookup_ordered_extent(inode, 494 offset); 495 ASSERT(ordered); /* Logic error */ 496 sums->bytenr = ((u64)bio->bi_iter.bi_sector << 9) 497 + total_bytes; 498 index = 0; 499 } 500 501 sums->sums[index] = ~(u32)0; 502 data = kmap_atomic(bvec.bv_page); 503 sums->sums[index] 504 = btrfs_csum_data(data + bvec.bv_offset 505 + (i * fs_info->sectorsize), 506 sums->sums[index], 507 fs_info->sectorsize); 508 kunmap_atomic(data); 509 btrfs_csum_final(sums->sums[index], 510 (char *)(sums->sums + index)); 511 index++; 512 offset += fs_info->sectorsize; 513 this_sum_bytes += fs_info->sectorsize; 514 total_bytes += fs_info->sectorsize; 515 } 516 517 } 518 this_sum_bytes = 0; 519 btrfs_add_ordered_sum(ordered, sums); 520 btrfs_put_ordered_extent(ordered); 521 return 0; 522 } 523 524 /* 525 * helper function for csum removal, this expects the 526 * key to describe the csum pointed to by the path, and it expects 527 * the csum to overlap the range [bytenr, len] 528 * 529 * The csum should not be entirely contained in the range and the 530 * range should not be entirely contained in the csum. 531 * 532 * This calls btrfs_truncate_item with the correct args based on the 533 * overlap, and fixes up the key as required. 534 */ 535 static noinline void truncate_one_csum(struct btrfs_fs_info *fs_info, 536 struct btrfs_path *path, 537 struct btrfs_key *key, 538 u64 bytenr, u64 len) 539 { 540 struct extent_buffer *leaf; 541 u16 csum_size = btrfs_super_csum_size(fs_info->super_copy); 542 u64 csum_end; 543 u64 end_byte = bytenr + len; 544 u32 blocksize_bits = fs_info->sb->s_blocksize_bits; 545 546 leaf = path->nodes[0]; 547 csum_end = btrfs_item_size_nr(leaf, path->slots[0]) / csum_size; 548 csum_end <<= fs_info->sb->s_blocksize_bits; 549 csum_end += key->offset; 550 551 if (key->offset < bytenr && csum_end <= end_byte) { 552 /* 553 * [ bytenr - len ] 554 * [ ] 555 * [csum ] 556 * A simple truncate off the end of the item 557 */ 558 u32 new_size = (bytenr - key->offset) >> blocksize_bits; 559 new_size *= csum_size; 560 btrfs_truncate_item(path, new_size, 1); 561 } else if (key->offset >= bytenr && csum_end > end_byte && 562 end_byte > key->offset) { 563 /* 564 * [ bytenr - len ] 565 * [ ] 566 * [csum ] 567 * we need to truncate from the beginning of the csum 568 */ 569 u32 new_size = (csum_end - end_byte) >> blocksize_bits; 570 new_size *= csum_size; 571 572 btrfs_truncate_item(path, new_size, 0); 573 574 key->offset = end_byte; 575 btrfs_set_item_key_safe(fs_info, path, key); 576 } else { 577 BUG(); 578 } 579 } 580 581 /* 582 * deletes the csum items from the csum tree for a given 583 * range of bytes. 584 */ 585 int btrfs_del_csums(struct btrfs_trans_handle *trans, 586 struct btrfs_fs_info *fs_info, u64 bytenr, u64 len) 587 { 588 struct btrfs_root *root = fs_info->csum_root; 589 struct btrfs_path *path; 590 struct btrfs_key key; 591 u64 end_byte = bytenr + len; 592 u64 csum_end; 593 struct extent_buffer *leaf; 594 int ret; 595 u16 csum_size = btrfs_super_csum_size(fs_info->super_copy); 596 int blocksize_bits = fs_info->sb->s_blocksize_bits; 597 598 path = btrfs_alloc_path(); 599 if (!path) 600 return -ENOMEM; 601 602 while (1) { 603 key.objectid = BTRFS_EXTENT_CSUM_OBJECTID; 604 key.offset = end_byte - 1; 605 key.type = BTRFS_EXTENT_CSUM_KEY; 606 607 path->leave_spinning = 1; 608 ret = btrfs_search_slot(trans, root, &key, path, -1, 1); 609 if (ret > 0) { 610 if (path->slots[0] == 0) 611 break; 612 path->slots[0]--; 613 } else if (ret < 0) { 614 break; 615 } 616 617 leaf = path->nodes[0]; 618 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]); 619 620 if (key.objectid != BTRFS_EXTENT_CSUM_OBJECTID || 621 key.type != BTRFS_EXTENT_CSUM_KEY) { 622 break; 623 } 624 625 if (key.offset >= end_byte) 626 break; 627 628 csum_end = btrfs_item_size_nr(leaf, path->slots[0]) / csum_size; 629 csum_end <<= blocksize_bits; 630 csum_end += key.offset; 631 632 /* this csum ends before we start, we're done */ 633 if (csum_end <= bytenr) 634 break; 635 636 /* delete the entire item, it is inside our range */ 637 if (key.offset >= bytenr && csum_end <= end_byte) { 638 int del_nr = 1; 639 640 /* 641 * Check how many csum items preceding this one in this 642 * leaf correspond to our range and then delete them all 643 * at once. 644 */ 645 if (key.offset > bytenr && path->slots[0] > 0) { 646 int slot = path->slots[0] - 1; 647 648 while (slot >= 0) { 649 struct btrfs_key pk; 650 651 btrfs_item_key_to_cpu(leaf, &pk, slot); 652 if (pk.offset < bytenr || 653 pk.type != BTRFS_EXTENT_CSUM_KEY || 654 pk.objectid != 655 BTRFS_EXTENT_CSUM_OBJECTID) 656 break; 657 path->slots[0] = slot; 658 del_nr++; 659 key.offset = pk.offset; 660 slot--; 661 } 662 } 663 ret = btrfs_del_items(trans, root, path, 664 path->slots[0], del_nr); 665 if (ret) 666 goto out; 667 if (key.offset == bytenr) 668 break; 669 } else if (key.offset < bytenr && csum_end > end_byte) { 670 unsigned long offset; 671 unsigned long shift_len; 672 unsigned long item_offset; 673 /* 674 * [ bytenr - len ] 675 * [csum ] 676 * 677 * Our bytes are in the middle of the csum, 678 * we need to split this item and insert a new one. 679 * 680 * But we can't drop the path because the 681 * csum could change, get removed, extended etc. 682 * 683 * The trick here is the max size of a csum item leaves 684 * enough room in the tree block for a single 685 * item header. So, we split the item in place, 686 * adding a new header pointing to the existing 687 * bytes. Then we loop around again and we have 688 * a nicely formed csum item that we can neatly 689 * truncate. 690 */ 691 offset = (bytenr - key.offset) >> blocksize_bits; 692 offset *= csum_size; 693 694 shift_len = (len >> blocksize_bits) * csum_size; 695 696 item_offset = btrfs_item_ptr_offset(leaf, 697 path->slots[0]); 698 699 memzero_extent_buffer(leaf, item_offset + offset, 700 shift_len); 701 key.offset = bytenr; 702 703 /* 704 * btrfs_split_item returns -EAGAIN when the 705 * item changed size or key 706 */ 707 ret = btrfs_split_item(trans, root, path, &key, offset); 708 if (ret && ret != -EAGAIN) { 709 btrfs_abort_transaction(trans, ret); 710 goto out; 711 } 712 713 key.offset = end_byte - 1; 714 } else { 715 truncate_one_csum(fs_info, path, &key, bytenr, len); 716 if (key.offset < bytenr) 717 break; 718 } 719 btrfs_release_path(path); 720 } 721 ret = 0; 722 out: 723 btrfs_free_path(path); 724 return ret; 725 } 726 727 int btrfs_csum_file_blocks(struct btrfs_trans_handle *trans, 728 struct btrfs_root *root, 729 struct btrfs_ordered_sum *sums) 730 { 731 struct btrfs_fs_info *fs_info = root->fs_info; 732 struct btrfs_key file_key; 733 struct btrfs_key found_key; 734 struct btrfs_path *path; 735 struct btrfs_csum_item *item; 736 struct btrfs_csum_item *item_end; 737 struct extent_buffer *leaf = NULL; 738 u64 next_offset; 739 u64 total_bytes = 0; 740 u64 csum_offset; 741 u64 bytenr; 742 u32 nritems; 743 u32 ins_size; 744 int index = 0; 745 int found_next; 746 int ret; 747 u16 csum_size = btrfs_super_csum_size(fs_info->super_copy); 748 749 path = btrfs_alloc_path(); 750 if (!path) 751 return -ENOMEM; 752 again: 753 next_offset = (u64)-1; 754 found_next = 0; 755 bytenr = sums->bytenr + total_bytes; 756 file_key.objectid = BTRFS_EXTENT_CSUM_OBJECTID; 757 file_key.offset = bytenr; 758 file_key.type = BTRFS_EXTENT_CSUM_KEY; 759 760 item = btrfs_lookup_csum(trans, root, path, bytenr, 1); 761 if (!IS_ERR(item)) { 762 ret = 0; 763 leaf = path->nodes[0]; 764 item_end = btrfs_item_ptr(leaf, path->slots[0], 765 struct btrfs_csum_item); 766 item_end = (struct btrfs_csum_item *)((char *)item_end + 767 btrfs_item_size_nr(leaf, path->slots[0])); 768 goto found; 769 } 770 ret = PTR_ERR(item); 771 if (ret != -EFBIG && ret != -ENOENT) 772 goto fail_unlock; 773 774 if (ret == -EFBIG) { 775 u32 item_size; 776 /* we found one, but it isn't big enough yet */ 777 leaf = path->nodes[0]; 778 item_size = btrfs_item_size_nr(leaf, path->slots[0]); 779 if ((item_size / csum_size) >= 780 MAX_CSUM_ITEMS(fs_info, csum_size)) { 781 /* already at max size, make a new one */ 782 goto insert; 783 } 784 } else { 785 int slot = path->slots[0] + 1; 786 /* we didn't find a csum item, insert one */ 787 nritems = btrfs_header_nritems(path->nodes[0]); 788 if (!nritems || (path->slots[0] >= nritems - 1)) { 789 ret = btrfs_next_leaf(root, path); 790 if (ret == 1) 791 found_next = 1; 792 if (ret != 0) 793 goto insert; 794 slot = path->slots[0]; 795 } 796 btrfs_item_key_to_cpu(path->nodes[0], &found_key, slot); 797 if (found_key.objectid != BTRFS_EXTENT_CSUM_OBJECTID || 798 found_key.type != BTRFS_EXTENT_CSUM_KEY) { 799 found_next = 1; 800 goto insert; 801 } 802 next_offset = found_key.offset; 803 found_next = 1; 804 goto insert; 805 } 806 807 /* 808 * at this point, we know the tree has an item, but it isn't big 809 * enough yet to put our csum in. Grow it 810 */ 811 btrfs_release_path(path); 812 ret = btrfs_search_slot(trans, root, &file_key, path, 813 csum_size, 1); 814 if (ret < 0) 815 goto fail_unlock; 816 817 if (ret > 0) { 818 if (path->slots[0] == 0) 819 goto insert; 820 path->slots[0]--; 821 } 822 823 leaf = path->nodes[0]; 824 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]); 825 csum_offset = (bytenr - found_key.offset) >> 826 fs_info->sb->s_blocksize_bits; 827 828 if (found_key.type != BTRFS_EXTENT_CSUM_KEY || 829 found_key.objectid != BTRFS_EXTENT_CSUM_OBJECTID || 830 csum_offset >= MAX_CSUM_ITEMS(fs_info, csum_size)) { 831 goto insert; 832 } 833 834 if (csum_offset == btrfs_item_size_nr(leaf, path->slots[0]) / 835 csum_size) { 836 int extend_nr; 837 u64 tmp; 838 u32 diff; 839 u32 free_space; 840 841 if (btrfs_leaf_free_space(leaf) < 842 sizeof(struct btrfs_item) + csum_size * 2) 843 goto insert; 844 845 free_space = btrfs_leaf_free_space(leaf) - 846 sizeof(struct btrfs_item) - csum_size; 847 tmp = sums->len - total_bytes; 848 tmp >>= fs_info->sb->s_blocksize_bits; 849 WARN_ON(tmp < 1); 850 851 extend_nr = max_t(int, 1, (int)tmp); 852 diff = (csum_offset + extend_nr) * csum_size; 853 diff = min(diff, 854 MAX_CSUM_ITEMS(fs_info, csum_size) * csum_size); 855 856 diff = diff - btrfs_item_size_nr(leaf, path->slots[0]); 857 diff = min(free_space, diff); 858 diff /= csum_size; 859 diff *= csum_size; 860 861 btrfs_extend_item(path, diff); 862 ret = 0; 863 goto csum; 864 } 865 866 insert: 867 btrfs_release_path(path); 868 csum_offset = 0; 869 if (found_next) { 870 u64 tmp; 871 872 tmp = sums->len - total_bytes; 873 tmp >>= fs_info->sb->s_blocksize_bits; 874 tmp = min(tmp, (next_offset - file_key.offset) >> 875 fs_info->sb->s_blocksize_bits); 876 877 tmp = max_t(u64, 1, tmp); 878 tmp = min_t(u64, tmp, MAX_CSUM_ITEMS(fs_info, csum_size)); 879 ins_size = csum_size * tmp; 880 } else { 881 ins_size = csum_size; 882 } 883 path->leave_spinning = 1; 884 ret = btrfs_insert_empty_item(trans, root, path, &file_key, 885 ins_size); 886 path->leave_spinning = 0; 887 if (ret < 0) 888 goto fail_unlock; 889 if (WARN_ON(ret != 0)) 890 goto fail_unlock; 891 leaf = path->nodes[0]; 892 csum: 893 item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_csum_item); 894 item_end = (struct btrfs_csum_item *)((unsigned char *)item + 895 btrfs_item_size_nr(leaf, path->slots[0])); 896 item = (struct btrfs_csum_item *)((unsigned char *)item + 897 csum_offset * csum_size); 898 found: 899 ins_size = (u32)(sums->len - total_bytes) >> 900 fs_info->sb->s_blocksize_bits; 901 ins_size *= csum_size; 902 ins_size = min_t(u32, (unsigned long)item_end - (unsigned long)item, 903 ins_size); 904 write_extent_buffer(leaf, sums->sums + index, (unsigned long)item, 905 ins_size); 906 907 ins_size /= csum_size; 908 total_bytes += ins_size * fs_info->sectorsize; 909 index += ins_size; 910 911 btrfs_mark_buffer_dirty(path->nodes[0]); 912 if (total_bytes < sums->len) { 913 btrfs_release_path(path); 914 cond_resched(); 915 goto again; 916 } 917 out: 918 btrfs_free_path(path); 919 return ret; 920 921 fail_unlock: 922 goto out; 923 } 924 925 void btrfs_extent_item_to_extent_map(struct btrfs_inode *inode, 926 const struct btrfs_path *path, 927 struct btrfs_file_extent_item *fi, 928 const bool new_inline, 929 struct extent_map *em) 930 { 931 struct btrfs_fs_info *fs_info = inode->root->fs_info; 932 struct btrfs_root *root = inode->root; 933 struct extent_buffer *leaf = path->nodes[0]; 934 const int slot = path->slots[0]; 935 struct btrfs_key key; 936 u64 extent_start, extent_end; 937 u64 bytenr; 938 u8 type = btrfs_file_extent_type(leaf, fi); 939 int compress_type = btrfs_file_extent_compression(leaf, fi); 940 941 em->bdev = fs_info->fs_devices->latest_bdev; 942 btrfs_item_key_to_cpu(leaf, &key, slot); 943 extent_start = key.offset; 944 945 if (type == BTRFS_FILE_EXTENT_REG || 946 type == BTRFS_FILE_EXTENT_PREALLOC) { 947 extent_end = extent_start + 948 btrfs_file_extent_num_bytes(leaf, fi); 949 } else if (type == BTRFS_FILE_EXTENT_INLINE) { 950 size_t size; 951 size = btrfs_file_extent_ram_bytes(leaf, fi); 952 extent_end = ALIGN(extent_start + size, 953 fs_info->sectorsize); 954 } 955 956 em->ram_bytes = btrfs_file_extent_ram_bytes(leaf, fi); 957 if (type == BTRFS_FILE_EXTENT_REG || 958 type == BTRFS_FILE_EXTENT_PREALLOC) { 959 em->start = extent_start; 960 em->len = extent_end - extent_start; 961 em->orig_start = extent_start - 962 btrfs_file_extent_offset(leaf, fi); 963 em->orig_block_len = btrfs_file_extent_disk_num_bytes(leaf, fi); 964 bytenr = btrfs_file_extent_disk_bytenr(leaf, fi); 965 if (bytenr == 0) { 966 em->block_start = EXTENT_MAP_HOLE; 967 return; 968 } 969 if (compress_type != BTRFS_COMPRESS_NONE) { 970 set_bit(EXTENT_FLAG_COMPRESSED, &em->flags); 971 em->compress_type = compress_type; 972 em->block_start = bytenr; 973 em->block_len = em->orig_block_len; 974 } else { 975 bytenr += btrfs_file_extent_offset(leaf, fi); 976 em->block_start = bytenr; 977 em->block_len = em->len; 978 if (type == BTRFS_FILE_EXTENT_PREALLOC) 979 set_bit(EXTENT_FLAG_PREALLOC, &em->flags); 980 } 981 } else if (type == BTRFS_FILE_EXTENT_INLINE) { 982 em->block_start = EXTENT_MAP_INLINE; 983 em->start = extent_start; 984 em->len = extent_end - extent_start; 985 /* 986 * Initialize orig_start and block_len with the same values 987 * as in inode.c:btrfs_get_extent(). 988 */ 989 em->orig_start = EXTENT_MAP_HOLE; 990 em->block_len = (u64)-1; 991 if (!new_inline && compress_type != BTRFS_COMPRESS_NONE) { 992 set_bit(EXTENT_FLAG_COMPRESSED, &em->flags); 993 em->compress_type = compress_type; 994 } 995 } else { 996 btrfs_err(fs_info, 997 "unknown file extent item type %d, inode %llu, offset %llu, " 998 "root %llu", type, btrfs_ino(inode), extent_start, 999 root->root_key.objectid); 1000 } 1001 } 1002