1 /* 2 * Copyright (C) 2007 Oracle. All rights reserved. 3 * 4 * This program is free software; you can redistribute it and/or 5 * modify it under the terms of the GNU General Public 6 * License v2 as published by the Free Software Foundation. 7 * 8 * This program is distributed in the hope that it will be useful, 9 * but WITHOUT ANY WARRANTY; without even the implied warranty of 10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 11 * General Public License for more details. 12 * 13 * You should have received a copy of the GNU General Public 14 * License along with this program; if not, write to the 15 * Free Software Foundation, Inc., 59 Temple Place - Suite 330, 16 * Boston, MA 021110-1307, USA. 17 */ 18 19 #include <linux/bio.h> 20 #include <linux/slab.h> 21 #include <linux/pagemap.h> 22 #include <linux/highmem.h> 23 #include "ctree.h" 24 #include "disk-io.h" 25 #include "transaction.h" 26 #include "print-tree.h" 27 28 #define MAX_CSUM_ITEMS(r, size) ((((BTRFS_LEAF_DATA_SIZE(r) - \ 29 sizeof(struct btrfs_item) * 2) / \ 30 size) - 1)) 31 32 #define MAX_ORDERED_SUM_BYTES(r) ((PAGE_SIZE - \ 33 sizeof(struct btrfs_ordered_sum)) / \ 34 sizeof(struct btrfs_sector_sum) * \ 35 (r)->sectorsize - (r)->sectorsize) 36 37 int btrfs_insert_file_extent(struct btrfs_trans_handle *trans, 38 struct btrfs_root *root, 39 u64 objectid, u64 pos, 40 u64 disk_offset, u64 disk_num_bytes, 41 u64 num_bytes, u64 offset, u64 ram_bytes, 42 u8 compression, u8 encryption, u16 other_encoding) 43 { 44 int ret = 0; 45 struct btrfs_file_extent_item *item; 46 struct btrfs_key file_key; 47 struct btrfs_path *path; 48 struct extent_buffer *leaf; 49 50 path = btrfs_alloc_path(); 51 if (!path) 52 return -ENOMEM; 53 file_key.objectid = objectid; 54 file_key.offset = pos; 55 btrfs_set_key_type(&file_key, BTRFS_EXTENT_DATA_KEY); 56 57 path->leave_spinning = 1; 58 ret = btrfs_insert_empty_item(trans, root, path, &file_key, 59 sizeof(*item)); 60 if (ret < 0) 61 goto out; 62 BUG_ON(ret); 63 leaf = path->nodes[0]; 64 item = btrfs_item_ptr(leaf, path->slots[0], 65 struct btrfs_file_extent_item); 66 btrfs_set_file_extent_disk_bytenr(leaf, item, disk_offset); 67 btrfs_set_file_extent_disk_num_bytes(leaf, item, disk_num_bytes); 68 btrfs_set_file_extent_offset(leaf, item, offset); 69 btrfs_set_file_extent_num_bytes(leaf, item, num_bytes); 70 btrfs_set_file_extent_ram_bytes(leaf, item, ram_bytes); 71 btrfs_set_file_extent_generation(leaf, item, trans->transid); 72 btrfs_set_file_extent_type(leaf, item, BTRFS_FILE_EXTENT_REG); 73 btrfs_set_file_extent_compression(leaf, item, compression); 74 btrfs_set_file_extent_encryption(leaf, item, encryption); 75 btrfs_set_file_extent_other_encoding(leaf, item, other_encoding); 76 77 btrfs_mark_buffer_dirty(leaf); 78 out: 79 btrfs_free_path(path); 80 return ret; 81 } 82 83 struct btrfs_csum_item *btrfs_lookup_csum(struct btrfs_trans_handle *trans, 84 struct btrfs_root *root, 85 struct btrfs_path *path, 86 u64 bytenr, int cow) 87 { 88 int ret; 89 struct btrfs_key file_key; 90 struct btrfs_key found_key; 91 struct btrfs_csum_item *item; 92 struct extent_buffer *leaf; 93 u64 csum_offset = 0; 94 u16 csum_size = btrfs_super_csum_size(root->fs_info->super_copy); 95 int csums_in_item; 96 97 file_key.objectid = BTRFS_EXTENT_CSUM_OBJECTID; 98 file_key.offset = bytenr; 99 btrfs_set_key_type(&file_key, BTRFS_EXTENT_CSUM_KEY); 100 ret = btrfs_search_slot(trans, root, &file_key, path, 0, cow); 101 if (ret < 0) 102 goto fail; 103 leaf = path->nodes[0]; 104 if (ret > 0) { 105 ret = 1; 106 if (path->slots[0] == 0) 107 goto fail; 108 path->slots[0]--; 109 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]); 110 if (btrfs_key_type(&found_key) != BTRFS_EXTENT_CSUM_KEY) 111 goto fail; 112 113 csum_offset = (bytenr - found_key.offset) >> 114 root->fs_info->sb->s_blocksize_bits; 115 csums_in_item = btrfs_item_size_nr(leaf, path->slots[0]); 116 csums_in_item /= csum_size; 117 118 if (csum_offset >= csums_in_item) { 119 ret = -EFBIG; 120 goto fail; 121 } 122 } 123 item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_csum_item); 124 item = (struct btrfs_csum_item *)((unsigned char *)item + 125 csum_offset * csum_size); 126 return item; 127 fail: 128 if (ret > 0) 129 ret = -ENOENT; 130 return ERR_PTR(ret); 131 } 132 133 134 int btrfs_lookup_file_extent(struct btrfs_trans_handle *trans, 135 struct btrfs_root *root, 136 struct btrfs_path *path, u64 objectid, 137 u64 offset, int mod) 138 { 139 int ret; 140 struct btrfs_key file_key; 141 int ins_len = mod < 0 ? -1 : 0; 142 int cow = mod != 0; 143 144 file_key.objectid = objectid; 145 file_key.offset = offset; 146 btrfs_set_key_type(&file_key, BTRFS_EXTENT_DATA_KEY); 147 ret = btrfs_search_slot(trans, root, &file_key, path, ins_len, cow); 148 return ret; 149 } 150 151 152 static int __btrfs_lookup_bio_sums(struct btrfs_root *root, 153 struct inode *inode, struct bio *bio, 154 u64 logical_offset, u32 *dst, int dio) 155 { 156 u32 sum; 157 struct bio_vec *bvec = bio->bi_io_vec; 158 int bio_index = 0; 159 u64 offset = 0; 160 u64 item_start_offset = 0; 161 u64 item_last_offset = 0; 162 u64 disk_bytenr; 163 u32 diff; 164 u16 csum_size = btrfs_super_csum_size(root->fs_info->super_copy); 165 int ret; 166 struct btrfs_path *path; 167 struct btrfs_csum_item *item = NULL; 168 struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree; 169 170 path = btrfs_alloc_path(); 171 if (!path) 172 return -ENOMEM; 173 if (bio->bi_size > PAGE_CACHE_SIZE * 8) 174 path->reada = 2; 175 176 WARN_ON(bio->bi_vcnt <= 0); 177 178 /* 179 * the free space stuff is only read when it hasn't been 180 * updated in the current transaction. So, we can safely 181 * read from the commit root and sidestep a nasty deadlock 182 * between reading the free space cache and updating the csum tree. 183 */ 184 if (btrfs_is_free_space_inode(root, inode)) { 185 path->search_commit_root = 1; 186 path->skip_locking = 1; 187 } 188 189 disk_bytenr = (u64)bio->bi_sector << 9; 190 if (dio) 191 offset = logical_offset; 192 while (bio_index < bio->bi_vcnt) { 193 if (!dio) 194 offset = page_offset(bvec->bv_page) + bvec->bv_offset; 195 ret = btrfs_find_ordered_sum(inode, offset, disk_bytenr, &sum); 196 if (ret == 0) 197 goto found; 198 199 if (!item || disk_bytenr < item_start_offset || 200 disk_bytenr >= item_last_offset) { 201 struct btrfs_key found_key; 202 u32 item_size; 203 204 if (item) 205 btrfs_release_path(path); 206 item = btrfs_lookup_csum(NULL, root->fs_info->csum_root, 207 path, disk_bytenr, 0); 208 if (IS_ERR(item)) { 209 ret = PTR_ERR(item); 210 if (ret == -ENOENT || ret == -EFBIG) 211 ret = 0; 212 sum = 0; 213 if (BTRFS_I(inode)->root->root_key.objectid == 214 BTRFS_DATA_RELOC_TREE_OBJECTID) { 215 set_extent_bits(io_tree, offset, 216 offset + bvec->bv_len - 1, 217 EXTENT_NODATASUM, GFP_NOFS); 218 } else { 219 printk(KERN_INFO "btrfs no csum found " 220 "for inode %llu start %llu\n", 221 (unsigned long long) 222 btrfs_ino(inode), 223 (unsigned long long)offset); 224 } 225 item = NULL; 226 btrfs_release_path(path); 227 goto found; 228 } 229 btrfs_item_key_to_cpu(path->nodes[0], &found_key, 230 path->slots[0]); 231 232 item_start_offset = found_key.offset; 233 item_size = btrfs_item_size_nr(path->nodes[0], 234 path->slots[0]); 235 item_last_offset = item_start_offset + 236 (item_size / csum_size) * 237 root->sectorsize; 238 item = btrfs_item_ptr(path->nodes[0], path->slots[0], 239 struct btrfs_csum_item); 240 } 241 /* 242 * this byte range must be able to fit inside 243 * a single leaf so it will also fit inside a u32 244 */ 245 diff = disk_bytenr - item_start_offset; 246 diff = diff / root->sectorsize; 247 diff = diff * csum_size; 248 249 read_extent_buffer(path->nodes[0], &sum, 250 ((unsigned long)item) + diff, 251 csum_size); 252 found: 253 if (dst) 254 *dst++ = sum; 255 else 256 set_state_private(io_tree, offset, sum); 257 disk_bytenr += bvec->bv_len; 258 offset += bvec->bv_len; 259 bio_index++; 260 bvec++; 261 } 262 btrfs_free_path(path); 263 return 0; 264 } 265 266 int btrfs_lookup_bio_sums(struct btrfs_root *root, struct inode *inode, 267 struct bio *bio, u32 *dst) 268 { 269 return __btrfs_lookup_bio_sums(root, inode, bio, 0, dst, 0); 270 } 271 272 int btrfs_lookup_bio_sums_dio(struct btrfs_root *root, struct inode *inode, 273 struct bio *bio, u64 offset, u32 *dst) 274 { 275 return __btrfs_lookup_bio_sums(root, inode, bio, offset, dst, 1); 276 } 277 278 int btrfs_lookup_csums_range(struct btrfs_root *root, u64 start, u64 end, 279 struct list_head *list, int search_commit) 280 { 281 struct btrfs_key key; 282 struct btrfs_path *path; 283 struct extent_buffer *leaf; 284 struct btrfs_ordered_sum *sums; 285 struct btrfs_sector_sum *sector_sum; 286 struct btrfs_csum_item *item; 287 unsigned long offset; 288 int ret; 289 size_t size; 290 u64 csum_end; 291 u16 csum_size = btrfs_super_csum_size(root->fs_info->super_copy); 292 293 path = btrfs_alloc_path(); 294 if (!path) 295 return -ENOMEM; 296 297 if (search_commit) { 298 path->skip_locking = 1; 299 path->reada = 2; 300 path->search_commit_root = 1; 301 } 302 303 key.objectid = BTRFS_EXTENT_CSUM_OBJECTID; 304 key.offset = start; 305 key.type = BTRFS_EXTENT_CSUM_KEY; 306 307 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0); 308 if (ret < 0) 309 goto fail; 310 if (ret > 0 && path->slots[0] > 0) { 311 leaf = path->nodes[0]; 312 btrfs_item_key_to_cpu(leaf, &key, path->slots[0] - 1); 313 if (key.objectid == BTRFS_EXTENT_CSUM_OBJECTID && 314 key.type == BTRFS_EXTENT_CSUM_KEY) { 315 offset = (start - key.offset) >> 316 root->fs_info->sb->s_blocksize_bits; 317 if (offset * csum_size < 318 btrfs_item_size_nr(leaf, path->slots[0] - 1)) 319 path->slots[0]--; 320 } 321 } 322 323 while (start <= end) { 324 leaf = path->nodes[0]; 325 if (path->slots[0] >= btrfs_header_nritems(leaf)) { 326 ret = btrfs_next_leaf(root, path); 327 if (ret < 0) 328 goto fail; 329 if (ret > 0) 330 break; 331 leaf = path->nodes[0]; 332 } 333 334 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]); 335 if (key.objectid != BTRFS_EXTENT_CSUM_OBJECTID || 336 key.type != BTRFS_EXTENT_CSUM_KEY) 337 break; 338 339 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]); 340 if (key.offset > end) 341 break; 342 343 if (key.offset > start) 344 start = key.offset; 345 346 size = btrfs_item_size_nr(leaf, path->slots[0]); 347 csum_end = key.offset + (size / csum_size) * root->sectorsize; 348 if (csum_end <= start) { 349 path->slots[0]++; 350 continue; 351 } 352 353 csum_end = min(csum_end, end + 1); 354 item = btrfs_item_ptr(path->nodes[0], path->slots[0], 355 struct btrfs_csum_item); 356 while (start < csum_end) { 357 size = min_t(size_t, csum_end - start, 358 MAX_ORDERED_SUM_BYTES(root)); 359 sums = kzalloc(btrfs_ordered_sum_size(root, size), 360 GFP_NOFS); 361 BUG_ON(!sums); 362 363 sector_sum = sums->sums; 364 sums->bytenr = start; 365 sums->len = size; 366 367 offset = (start - key.offset) >> 368 root->fs_info->sb->s_blocksize_bits; 369 offset *= csum_size; 370 371 while (size > 0) { 372 read_extent_buffer(path->nodes[0], 373 §or_sum->sum, 374 ((unsigned long)item) + 375 offset, csum_size); 376 sector_sum->bytenr = start; 377 378 size -= root->sectorsize; 379 start += root->sectorsize; 380 offset += csum_size; 381 sector_sum++; 382 } 383 list_add_tail(&sums->list, list); 384 } 385 path->slots[0]++; 386 } 387 ret = 0; 388 fail: 389 btrfs_free_path(path); 390 return ret; 391 } 392 393 int btrfs_csum_one_bio(struct btrfs_root *root, struct inode *inode, 394 struct bio *bio, u64 file_start, int contig) 395 { 396 struct btrfs_ordered_sum *sums; 397 struct btrfs_sector_sum *sector_sum; 398 struct btrfs_ordered_extent *ordered; 399 char *data; 400 struct bio_vec *bvec = bio->bi_io_vec; 401 int bio_index = 0; 402 unsigned long total_bytes = 0; 403 unsigned long this_sum_bytes = 0; 404 u64 offset; 405 u64 disk_bytenr; 406 407 WARN_ON(bio->bi_vcnt <= 0); 408 sums = kzalloc(btrfs_ordered_sum_size(root, bio->bi_size), GFP_NOFS); 409 if (!sums) 410 return -ENOMEM; 411 412 sector_sum = sums->sums; 413 disk_bytenr = (u64)bio->bi_sector << 9; 414 sums->len = bio->bi_size; 415 INIT_LIST_HEAD(&sums->list); 416 417 if (contig) 418 offset = file_start; 419 else 420 offset = page_offset(bvec->bv_page) + bvec->bv_offset; 421 422 ordered = btrfs_lookup_ordered_extent(inode, offset); 423 BUG_ON(!ordered); 424 sums->bytenr = ordered->start; 425 426 while (bio_index < bio->bi_vcnt) { 427 if (!contig) 428 offset = page_offset(bvec->bv_page) + bvec->bv_offset; 429 430 if (!contig && (offset >= ordered->file_offset + ordered->len || 431 offset < ordered->file_offset)) { 432 unsigned long bytes_left; 433 sums->len = this_sum_bytes; 434 this_sum_bytes = 0; 435 btrfs_add_ordered_sum(inode, ordered, sums); 436 btrfs_put_ordered_extent(ordered); 437 438 bytes_left = bio->bi_size - total_bytes; 439 440 sums = kzalloc(btrfs_ordered_sum_size(root, bytes_left), 441 GFP_NOFS); 442 BUG_ON(!sums); 443 sector_sum = sums->sums; 444 sums->len = bytes_left; 445 ordered = btrfs_lookup_ordered_extent(inode, offset); 446 BUG_ON(!ordered); 447 sums->bytenr = ordered->start; 448 } 449 450 data = kmap_atomic(bvec->bv_page, KM_USER0); 451 sector_sum->sum = ~(u32)0; 452 sector_sum->sum = btrfs_csum_data(root, 453 data + bvec->bv_offset, 454 sector_sum->sum, 455 bvec->bv_len); 456 kunmap_atomic(data, KM_USER0); 457 btrfs_csum_final(sector_sum->sum, 458 (char *)§or_sum->sum); 459 sector_sum->bytenr = disk_bytenr; 460 461 sector_sum++; 462 bio_index++; 463 total_bytes += bvec->bv_len; 464 this_sum_bytes += bvec->bv_len; 465 disk_bytenr += bvec->bv_len; 466 offset += bvec->bv_len; 467 bvec++; 468 } 469 this_sum_bytes = 0; 470 btrfs_add_ordered_sum(inode, ordered, sums); 471 btrfs_put_ordered_extent(ordered); 472 return 0; 473 } 474 475 /* 476 * helper function for csum removal, this expects the 477 * key to describe the csum pointed to by the path, and it expects 478 * the csum to overlap the range [bytenr, len] 479 * 480 * The csum should not be entirely contained in the range and the 481 * range should not be entirely contained in the csum. 482 * 483 * This calls btrfs_truncate_item with the correct args based on the 484 * overlap, and fixes up the key as required. 485 */ 486 static noinline void truncate_one_csum(struct btrfs_trans_handle *trans, 487 struct btrfs_root *root, 488 struct btrfs_path *path, 489 struct btrfs_key *key, 490 u64 bytenr, u64 len) 491 { 492 struct extent_buffer *leaf; 493 u16 csum_size = btrfs_super_csum_size(root->fs_info->super_copy); 494 u64 csum_end; 495 u64 end_byte = bytenr + len; 496 u32 blocksize_bits = root->fs_info->sb->s_blocksize_bits; 497 498 leaf = path->nodes[0]; 499 csum_end = btrfs_item_size_nr(leaf, path->slots[0]) / csum_size; 500 csum_end <<= root->fs_info->sb->s_blocksize_bits; 501 csum_end += key->offset; 502 503 if (key->offset < bytenr && csum_end <= end_byte) { 504 /* 505 * [ bytenr - len ] 506 * [ ] 507 * [csum ] 508 * A simple truncate off the end of the item 509 */ 510 u32 new_size = (bytenr - key->offset) >> blocksize_bits; 511 new_size *= csum_size; 512 btrfs_truncate_item(trans, root, path, new_size, 1); 513 } else if (key->offset >= bytenr && csum_end > end_byte && 514 end_byte > key->offset) { 515 /* 516 * [ bytenr - len ] 517 * [ ] 518 * [csum ] 519 * we need to truncate from the beginning of the csum 520 */ 521 u32 new_size = (csum_end - end_byte) >> blocksize_bits; 522 new_size *= csum_size; 523 524 btrfs_truncate_item(trans, root, path, new_size, 0); 525 526 key->offset = end_byte; 527 btrfs_set_item_key_safe(trans, root, path, key); 528 } else { 529 BUG(); 530 } 531 } 532 533 /* 534 * deletes the csum items from the csum tree for a given 535 * range of bytes. 536 */ 537 int btrfs_del_csums(struct btrfs_trans_handle *trans, 538 struct btrfs_root *root, u64 bytenr, u64 len) 539 { 540 struct btrfs_path *path; 541 struct btrfs_key key; 542 u64 end_byte = bytenr + len; 543 u64 csum_end; 544 struct extent_buffer *leaf; 545 int ret; 546 u16 csum_size = btrfs_super_csum_size(root->fs_info->super_copy); 547 int blocksize_bits = root->fs_info->sb->s_blocksize_bits; 548 549 root = root->fs_info->csum_root; 550 551 path = btrfs_alloc_path(); 552 if (!path) 553 return -ENOMEM; 554 555 while (1) { 556 key.objectid = BTRFS_EXTENT_CSUM_OBJECTID; 557 key.offset = end_byte - 1; 558 key.type = BTRFS_EXTENT_CSUM_KEY; 559 560 path->leave_spinning = 1; 561 ret = btrfs_search_slot(trans, root, &key, path, -1, 1); 562 if (ret > 0) { 563 if (path->slots[0] == 0) 564 break; 565 path->slots[0]--; 566 } else if (ret < 0) { 567 break; 568 } 569 570 leaf = path->nodes[0]; 571 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]); 572 573 if (key.objectid != BTRFS_EXTENT_CSUM_OBJECTID || 574 key.type != BTRFS_EXTENT_CSUM_KEY) { 575 break; 576 } 577 578 if (key.offset >= end_byte) 579 break; 580 581 csum_end = btrfs_item_size_nr(leaf, path->slots[0]) / csum_size; 582 csum_end <<= blocksize_bits; 583 csum_end += key.offset; 584 585 /* this csum ends before we start, we're done */ 586 if (csum_end <= bytenr) 587 break; 588 589 /* delete the entire item, it is inside our range */ 590 if (key.offset >= bytenr && csum_end <= end_byte) { 591 ret = btrfs_del_item(trans, root, path); 592 if (ret) 593 goto out; 594 if (key.offset == bytenr) 595 break; 596 } else if (key.offset < bytenr && csum_end > end_byte) { 597 unsigned long offset; 598 unsigned long shift_len; 599 unsigned long item_offset; 600 /* 601 * [ bytenr - len ] 602 * [csum ] 603 * 604 * Our bytes are in the middle of the csum, 605 * we need to split this item and insert a new one. 606 * 607 * But we can't drop the path because the 608 * csum could change, get removed, extended etc. 609 * 610 * The trick here is the max size of a csum item leaves 611 * enough room in the tree block for a single 612 * item header. So, we split the item in place, 613 * adding a new header pointing to the existing 614 * bytes. Then we loop around again and we have 615 * a nicely formed csum item that we can neatly 616 * truncate. 617 */ 618 offset = (bytenr - key.offset) >> blocksize_bits; 619 offset *= csum_size; 620 621 shift_len = (len >> blocksize_bits) * csum_size; 622 623 item_offset = btrfs_item_ptr_offset(leaf, 624 path->slots[0]); 625 626 memset_extent_buffer(leaf, 0, item_offset + offset, 627 shift_len); 628 key.offset = bytenr; 629 630 /* 631 * btrfs_split_item returns -EAGAIN when the 632 * item changed size or key 633 */ 634 ret = btrfs_split_item(trans, root, path, &key, offset); 635 BUG_ON(ret && ret != -EAGAIN); 636 637 key.offset = end_byte - 1; 638 } else { 639 truncate_one_csum(trans, root, path, &key, bytenr, len); 640 if (key.offset < bytenr) 641 break; 642 } 643 btrfs_release_path(path); 644 } 645 ret = 0; 646 out: 647 btrfs_free_path(path); 648 return ret; 649 } 650 651 int btrfs_csum_file_blocks(struct btrfs_trans_handle *trans, 652 struct btrfs_root *root, 653 struct btrfs_ordered_sum *sums) 654 { 655 u64 bytenr; 656 int ret; 657 struct btrfs_key file_key; 658 struct btrfs_key found_key; 659 u64 next_offset; 660 u64 total_bytes = 0; 661 int found_next; 662 struct btrfs_path *path; 663 struct btrfs_csum_item *item; 664 struct btrfs_csum_item *item_end; 665 struct extent_buffer *leaf = NULL; 666 u64 csum_offset; 667 struct btrfs_sector_sum *sector_sum; 668 u32 nritems; 669 u32 ins_size; 670 u16 csum_size = btrfs_super_csum_size(root->fs_info->super_copy); 671 672 path = btrfs_alloc_path(); 673 if (!path) 674 return -ENOMEM; 675 676 sector_sum = sums->sums; 677 again: 678 next_offset = (u64)-1; 679 found_next = 0; 680 file_key.objectid = BTRFS_EXTENT_CSUM_OBJECTID; 681 file_key.offset = sector_sum->bytenr; 682 bytenr = sector_sum->bytenr; 683 btrfs_set_key_type(&file_key, BTRFS_EXTENT_CSUM_KEY); 684 685 item = btrfs_lookup_csum(trans, root, path, sector_sum->bytenr, 1); 686 if (!IS_ERR(item)) { 687 leaf = path->nodes[0]; 688 ret = 0; 689 goto found; 690 } 691 ret = PTR_ERR(item); 692 if (ret != -EFBIG && ret != -ENOENT) 693 goto fail_unlock; 694 695 if (ret == -EFBIG) { 696 u32 item_size; 697 /* we found one, but it isn't big enough yet */ 698 leaf = path->nodes[0]; 699 item_size = btrfs_item_size_nr(leaf, path->slots[0]); 700 if ((item_size / csum_size) >= 701 MAX_CSUM_ITEMS(root, csum_size)) { 702 /* already at max size, make a new one */ 703 goto insert; 704 } 705 } else { 706 int slot = path->slots[0] + 1; 707 /* we didn't find a csum item, insert one */ 708 nritems = btrfs_header_nritems(path->nodes[0]); 709 if (path->slots[0] >= nritems - 1) { 710 ret = btrfs_next_leaf(root, path); 711 if (ret == 1) 712 found_next = 1; 713 if (ret != 0) 714 goto insert; 715 slot = 0; 716 } 717 btrfs_item_key_to_cpu(path->nodes[0], &found_key, slot); 718 if (found_key.objectid != BTRFS_EXTENT_CSUM_OBJECTID || 719 found_key.type != BTRFS_EXTENT_CSUM_KEY) { 720 found_next = 1; 721 goto insert; 722 } 723 next_offset = found_key.offset; 724 found_next = 1; 725 goto insert; 726 } 727 728 /* 729 * at this point, we know the tree has an item, but it isn't big 730 * enough yet to put our csum in. Grow it 731 */ 732 btrfs_release_path(path); 733 ret = btrfs_search_slot(trans, root, &file_key, path, 734 csum_size, 1); 735 if (ret < 0) 736 goto fail_unlock; 737 738 if (ret > 0) { 739 if (path->slots[0] == 0) 740 goto insert; 741 path->slots[0]--; 742 } 743 744 leaf = path->nodes[0]; 745 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]); 746 csum_offset = (bytenr - found_key.offset) >> 747 root->fs_info->sb->s_blocksize_bits; 748 749 if (btrfs_key_type(&found_key) != BTRFS_EXTENT_CSUM_KEY || 750 found_key.objectid != BTRFS_EXTENT_CSUM_OBJECTID || 751 csum_offset >= MAX_CSUM_ITEMS(root, csum_size)) { 752 goto insert; 753 } 754 755 if (csum_offset >= btrfs_item_size_nr(leaf, path->slots[0]) / 756 csum_size) { 757 u32 diff = (csum_offset + 1) * csum_size; 758 759 /* 760 * is the item big enough already? we dropped our lock 761 * before and need to recheck 762 */ 763 if (diff < btrfs_item_size_nr(leaf, path->slots[0])) 764 goto csum; 765 766 diff = diff - btrfs_item_size_nr(leaf, path->slots[0]); 767 if (diff != csum_size) 768 goto insert; 769 770 btrfs_extend_item(trans, root, path, diff); 771 goto csum; 772 } 773 774 insert: 775 btrfs_release_path(path); 776 csum_offset = 0; 777 if (found_next) { 778 u64 tmp = total_bytes + root->sectorsize; 779 u64 next_sector = sector_sum->bytenr; 780 struct btrfs_sector_sum *next = sector_sum + 1; 781 782 while (tmp < sums->len) { 783 if (next_sector + root->sectorsize != next->bytenr) 784 break; 785 tmp += root->sectorsize; 786 next_sector = next->bytenr; 787 next++; 788 } 789 tmp = min(tmp, next_offset - file_key.offset); 790 tmp >>= root->fs_info->sb->s_blocksize_bits; 791 tmp = max((u64)1, tmp); 792 tmp = min(tmp, (u64)MAX_CSUM_ITEMS(root, csum_size)); 793 ins_size = csum_size * tmp; 794 } else { 795 ins_size = csum_size; 796 } 797 path->leave_spinning = 1; 798 ret = btrfs_insert_empty_item(trans, root, path, &file_key, 799 ins_size); 800 path->leave_spinning = 0; 801 if (ret < 0) 802 goto fail_unlock; 803 if (ret != 0) { 804 WARN_ON(1); 805 goto fail_unlock; 806 } 807 csum: 808 leaf = path->nodes[0]; 809 item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_csum_item); 810 ret = 0; 811 item = (struct btrfs_csum_item *)((unsigned char *)item + 812 csum_offset * csum_size); 813 found: 814 item_end = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_csum_item); 815 item_end = (struct btrfs_csum_item *)((unsigned char *)item_end + 816 btrfs_item_size_nr(leaf, path->slots[0])); 817 next_sector: 818 819 write_extent_buffer(leaf, §or_sum->sum, (unsigned long)item, csum_size); 820 821 total_bytes += root->sectorsize; 822 sector_sum++; 823 if (total_bytes < sums->len) { 824 item = (struct btrfs_csum_item *)((char *)item + 825 csum_size); 826 if (item < item_end && bytenr + PAGE_CACHE_SIZE == 827 sector_sum->bytenr) { 828 bytenr = sector_sum->bytenr; 829 goto next_sector; 830 } 831 } 832 833 btrfs_mark_buffer_dirty(path->nodes[0]); 834 if (total_bytes < sums->len) { 835 btrfs_release_path(path); 836 cond_resched(); 837 goto again; 838 } 839 out: 840 btrfs_free_path(path); 841 return ret; 842 843 fail_unlock: 844 goto out; 845 } 846