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 = 95 btrfs_super_csum_size(&root->fs_info->super_copy); 96 int csums_in_item; 97 98 file_key.objectid = BTRFS_EXTENT_CSUM_OBJECTID; 99 file_key.offset = bytenr; 100 btrfs_set_key_type(&file_key, BTRFS_EXTENT_CSUM_KEY); 101 ret = btrfs_search_slot(trans, root, &file_key, path, 0, cow); 102 if (ret < 0) 103 goto fail; 104 leaf = path->nodes[0]; 105 if (ret > 0) { 106 ret = 1; 107 if (path->slots[0] == 0) 108 goto fail; 109 path->slots[0]--; 110 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]); 111 if (btrfs_key_type(&found_key) != BTRFS_EXTENT_CSUM_KEY) 112 goto fail; 113 114 csum_offset = (bytenr - found_key.offset) >> 115 root->fs_info->sb->s_blocksize_bits; 116 csums_in_item = btrfs_item_size_nr(leaf, path->slots[0]); 117 csums_in_item /= csum_size; 118 119 if (csum_offset >= csums_in_item) { 120 ret = -EFBIG; 121 goto fail; 122 } 123 } 124 item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_csum_item); 125 item = (struct btrfs_csum_item *)((unsigned char *)item + 126 csum_offset * csum_size); 127 return item; 128 fail: 129 if (ret > 0) 130 ret = -ENOENT; 131 return ERR_PTR(ret); 132 } 133 134 135 int btrfs_lookup_file_extent(struct btrfs_trans_handle *trans, 136 struct btrfs_root *root, 137 struct btrfs_path *path, u64 objectid, 138 u64 offset, int mod) 139 { 140 int ret; 141 struct btrfs_key file_key; 142 int ins_len = mod < 0 ? -1 : 0; 143 int cow = mod != 0; 144 145 file_key.objectid = objectid; 146 file_key.offset = offset; 147 btrfs_set_key_type(&file_key, BTRFS_EXTENT_DATA_KEY); 148 ret = btrfs_search_slot(trans, root, &file_key, path, ins_len, cow); 149 return ret; 150 } 151 152 153 static int __btrfs_lookup_bio_sums(struct btrfs_root *root, 154 struct inode *inode, struct bio *bio, 155 u64 logical_offset, u32 *dst, int dio) 156 { 157 u32 sum; 158 struct bio_vec *bvec = bio->bi_io_vec; 159 int bio_index = 0; 160 u64 offset = 0; 161 u64 item_start_offset = 0; 162 u64 item_last_offset = 0; 163 u64 disk_bytenr; 164 u32 diff; 165 u16 csum_size = 166 btrfs_super_csum_size(&root->fs_info->super_copy); 167 int ret; 168 struct btrfs_path *path; 169 struct btrfs_csum_item *item = NULL; 170 struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree; 171 172 path = btrfs_alloc_path(); 173 if (!path) 174 return -ENOMEM; 175 if (bio->bi_size > PAGE_CACHE_SIZE * 8) 176 path->reada = 2; 177 178 WARN_ON(bio->bi_vcnt <= 0); 179 180 disk_bytenr = (u64)bio->bi_sector << 9; 181 if (dio) 182 offset = logical_offset; 183 while (bio_index < bio->bi_vcnt) { 184 if (!dio) 185 offset = page_offset(bvec->bv_page) + bvec->bv_offset; 186 ret = btrfs_find_ordered_sum(inode, offset, disk_bytenr, &sum); 187 if (ret == 0) 188 goto found; 189 190 if (!item || disk_bytenr < item_start_offset || 191 disk_bytenr >= item_last_offset) { 192 struct btrfs_key found_key; 193 u32 item_size; 194 195 if (item) 196 btrfs_release_path(path); 197 item = btrfs_lookup_csum(NULL, root->fs_info->csum_root, 198 path, disk_bytenr, 0); 199 if (IS_ERR(item)) { 200 ret = PTR_ERR(item); 201 if (ret == -ENOENT || ret == -EFBIG) 202 ret = 0; 203 sum = 0; 204 if (BTRFS_I(inode)->root->root_key.objectid == 205 BTRFS_DATA_RELOC_TREE_OBJECTID) { 206 set_extent_bits(io_tree, offset, 207 offset + bvec->bv_len - 1, 208 EXTENT_NODATASUM, GFP_NOFS); 209 } else { 210 printk(KERN_INFO "btrfs no csum found " 211 "for inode %llu start %llu\n", 212 (unsigned long long) 213 btrfs_ino(inode), 214 (unsigned long long)offset); 215 } 216 item = NULL; 217 btrfs_release_path(path); 218 goto found; 219 } 220 btrfs_item_key_to_cpu(path->nodes[0], &found_key, 221 path->slots[0]); 222 223 item_start_offset = found_key.offset; 224 item_size = btrfs_item_size_nr(path->nodes[0], 225 path->slots[0]); 226 item_last_offset = item_start_offset + 227 (item_size / csum_size) * 228 root->sectorsize; 229 item = btrfs_item_ptr(path->nodes[0], path->slots[0], 230 struct btrfs_csum_item); 231 } 232 /* 233 * this byte range must be able to fit inside 234 * a single leaf so it will also fit inside a u32 235 */ 236 diff = disk_bytenr - item_start_offset; 237 diff = diff / root->sectorsize; 238 diff = diff * csum_size; 239 240 read_extent_buffer(path->nodes[0], &sum, 241 ((unsigned long)item) + diff, 242 csum_size); 243 found: 244 if (dst) 245 *dst++ = sum; 246 else 247 set_state_private(io_tree, offset, sum); 248 disk_bytenr += bvec->bv_len; 249 offset += bvec->bv_len; 250 bio_index++; 251 bvec++; 252 } 253 btrfs_free_path(path); 254 return 0; 255 } 256 257 int btrfs_lookup_bio_sums(struct btrfs_root *root, struct inode *inode, 258 struct bio *bio, u32 *dst) 259 { 260 return __btrfs_lookup_bio_sums(root, inode, bio, 0, dst, 0); 261 } 262 263 int btrfs_lookup_bio_sums_dio(struct btrfs_root *root, struct inode *inode, 264 struct bio *bio, u64 offset, u32 *dst) 265 { 266 return __btrfs_lookup_bio_sums(root, inode, bio, offset, dst, 1); 267 } 268 269 int btrfs_lookup_csums_range(struct btrfs_root *root, u64 start, u64 end, 270 struct list_head *list, int search_commit) 271 { 272 struct btrfs_key key; 273 struct btrfs_path *path; 274 struct extent_buffer *leaf; 275 struct btrfs_ordered_sum *sums; 276 struct btrfs_sector_sum *sector_sum; 277 struct btrfs_csum_item *item; 278 unsigned long offset; 279 int ret; 280 size_t size; 281 u64 csum_end; 282 u16 csum_size = btrfs_super_csum_size(&root->fs_info->super_copy); 283 284 path = btrfs_alloc_path(); 285 BUG_ON(!path); 286 287 if (search_commit) { 288 path->skip_locking = 1; 289 path->reada = 2; 290 path->search_commit_root = 1; 291 } 292 293 key.objectid = BTRFS_EXTENT_CSUM_OBJECTID; 294 key.offset = start; 295 key.type = BTRFS_EXTENT_CSUM_KEY; 296 297 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0); 298 if (ret < 0) 299 goto fail; 300 if (ret > 0 && path->slots[0] > 0) { 301 leaf = path->nodes[0]; 302 btrfs_item_key_to_cpu(leaf, &key, path->slots[0] - 1); 303 if (key.objectid == BTRFS_EXTENT_CSUM_OBJECTID && 304 key.type == BTRFS_EXTENT_CSUM_KEY) { 305 offset = (start - key.offset) >> 306 root->fs_info->sb->s_blocksize_bits; 307 if (offset * csum_size < 308 btrfs_item_size_nr(leaf, path->slots[0] - 1)) 309 path->slots[0]--; 310 } 311 } 312 313 while (start <= end) { 314 leaf = path->nodes[0]; 315 if (path->slots[0] >= btrfs_header_nritems(leaf)) { 316 ret = btrfs_next_leaf(root, path); 317 if (ret < 0) 318 goto fail; 319 if (ret > 0) 320 break; 321 leaf = path->nodes[0]; 322 } 323 324 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]); 325 if (key.objectid != BTRFS_EXTENT_CSUM_OBJECTID || 326 key.type != BTRFS_EXTENT_CSUM_KEY) 327 break; 328 329 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]); 330 if (key.offset > end) 331 break; 332 333 if (key.offset > start) 334 start = key.offset; 335 336 size = btrfs_item_size_nr(leaf, path->slots[0]); 337 csum_end = key.offset + (size / csum_size) * root->sectorsize; 338 if (csum_end <= start) { 339 path->slots[0]++; 340 continue; 341 } 342 343 csum_end = min(csum_end, end + 1); 344 item = btrfs_item_ptr(path->nodes[0], path->slots[0], 345 struct btrfs_csum_item); 346 while (start < csum_end) { 347 size = min_t(size_t, csum_end - start, 348 MAX_ORDERED_SUM_BYTES(root)); 349 sums = kzalloc(btrfs_ordered_sum_size(root, size), 350 GFP_NOFS); 351 BUG_ON(!sums); 352 353 sector_sum = sums->sums; 354 sums->bytenr = start; 355 sums->len = size; 356 357 offset = (start - key.offset) >> 358 root->fs_info->sb->s_blocksize_bits; 359 offset *= csum_size; 360 361 while (size > 0) { 362 read_extent_buffer(path->nodes[0], 363 §or_sum->sum, 364 ((unsigned long)item) + 365 offset, csum_size); 366 sector_sum->bytenr = start; 367 368 size -= root->sectorsize; 369 start += root->sectorsize; 370 offset += csum_size; 371 sector_sum++; 372 } 373 list_add_tail(&sums->list, list); 374 } 375 path->slots[0]++; 376 } 377 ret = 0; 378 fail: 379 btrfs_free_path(path); 380 return ret; 381 } 382 383 int btrfs_csum_one_bio(struct btrfs_root *root, struct inode *inode, 384 struct bio *bio, u64 file_start, int contig) 385 { 386 struct btrfs_ordered_sum *sums; 387 struct btrfs_sector_sum *sector_sum; 388 struct btrfs_ordered_extent *ordered; 389 char *data; 390 struct bio_vec *bvec = bio->bi_io_vec; 391 int bio_index = 0; 392 unsigned long total_bytes = 0; 393 unsigned long this_sum_bytes = 0; 394 u64 offset; 395 u64 disk_bytenr; 396 397 WARN_ON(bio->bi_vcnt <= 0); 398 sums = kzalloc(btrfs_ordered_sum_size(root, bio->bi_size), GFP_NOFS); 399 if (!sums) 400 return -ENOMEM; 401 402 sector_sum = sums->sums; 403 disk_bytenr = (u64)bio->bi_sector << 9; 404 sums->len = bio->bi_size; 405 INIT_LIST_HEAD(&sums->list); 406 407 if (contig) 408 offset = file_start; 409 else 410 offset = page_offset(bvec->bv_page) + bvec->bv_offset; 411 412 ordered = btrfs_lookup_ordered_extent(inode, offset); 413 BUG_ON(!ordered); 414 sums->bytenr = ordered->start; 415 416 while (bio_index < bio->bi_vcnt) { 417 if (!contig) 418 offset = page_offset(bvec->bv_page) + bvec->bv_offset; 419 420 if (!contig && (offset >= ordered->file_offset + ordered->len || 421 offset < ordered->file_offset)) { 422 unsigned long bytes_left; 423 sums->len = this_sum_bytes; 424 this_sum_bytes = 0; 425 btrfs_add_ordered_sum(inode, ordered, sums); 426 btrfs_put_ordered_extent(ordered); 427 428 bytes_left = bio->bi_size - total_bytes; 429 430 sums = kzalloc(btrfs_ordered_sum_size(root, bytes_left), 431 GFP_NOFS); 432 BUG_ON(!sums); 433 sector_sum = sums->sums; 434 sums->len = bytes_left; 435 ordered = btrfs_lookup_ordered_extent(inode, offset); 436 BUG_ON(!ordered); 437 sums->bytenr = ordered->start; 438 } 439 440 data = kmap_atomic(bvec->bv_page, KM_USER0); 441 sector_sum->sum = ~(u32)0; 442 sector_sum->sum = btrfs_csum_data(root, 443 data + bvec->bv_offset, 444 sector_sum->sum, 445 bvec->bv_len); 446 kunmap_atomic(data, KM_USER0); 447 btrfs_csum_final(sector_sum->sum, 448 (char *)§or_sum->sum); 449 sector_sum->bytenr = disk_bytenr; 450 451 sector_sum++; 452 bio_index++; 453 total_bytes += bvec->bv_len; 454 this_sum_bytes += bvec->bv_len; 455 disk_bytenr += bvec->bv_len; 456 offset += bvec->bv_len; 457 bvec++; 458 } 459 this_sum_bytes = 0; 460 btrfs_add_ordered_sum(inode, ordered, sums); 461 btrfs_put_ordered_extent(ordered); 462 return 0; 463 } 464 465 /* 466 * helper function for csum removal, this expects the 467 * key to describe the csum pointed to by the path, and it expects 468 * the csum to overlap the range [bytenr, len] 469 * 470 * The csum should not be entirely contained in the range and the 471 * range should not be entirely contained in the csum. 472 * 473 * This calls btrfs_truncate_item with the correct args based on the 474 * overlap, and fixes up the key as required. 475 */ 476 static noinline int truncate_one_csum(struct btrfs_trans_handle *trans, 477 struct btrfs_root *root, 478 struct btrfs_path *path, 479 struct btrfs_key *key, 480 u64 bytenr, u64 len) 481 { 482 struct extent_buffer *leaf; 483 u16 csum_size = 484 btrfs_super_csum_size(&root->fs_info->super_copy); 485 u64 csum_end; 486 u64 end_byte = bytenr + len; 487 u32 blocksize_bits = root->fs_info->sb->s_blocksize_bits; 488 int ret; 489 490 leaf = path->nodes[0]; 491 csum_end = btrfs_item_size_nr(leaf, path->slots[0]) / csum_size; 492 csum_end <<= root->fs_info->sb->s_blocksize_bits; 493 csum_end += key->offset; 494 495 if (key->offset < bytenr && csum_end <= end_byte) { 496 /* 497 * [ bytenr - len ] 498 * [ ] 499 * [csum ] 500 * A simple truncate off the end of the item 501 */ 502 u32 new_size = (bytenr - key->offset) >> blocksize_bits; 503 new_size *= csum_size; 504 ret = btrfs_truncate_item(trans, root, path, new_size, 1); 505 } else if (key->offset >= bytenr && csum_end > end_byte && 506 end_byte > key->offset) { 507 /* 508 * [ bytenr - len ] 509 * [ ] 510 * [csum ] 511 * we need to truncate from the beginning of the csum 512 */ 513 u32 new_size = (csum_end - end_byte) >> blocksize_bits; 514 new_size *= csum_size; 515 516 ret = btrfs_truncate_item(trans, root, path, new_size, 0); 517 518 key->offset = end_byte; 519 ret = btrfs_set_item_key_safe(trans, root, path, key); 520 BUG_ON(ret); 521 } else { 522 BUG(); 523 } 524 return 0; 525 } 526 527 /* 528 * deletes the csum items from the csum tree for a given 529 * range of bytes. 530 */ 531 int btrfs_del_csums(struct btrfs_trans_handle *trans, 532 struct btrfs_root *root, u64 bytenr, u64 len) 533 { 534 struct btrfs_path *path; 535 struct btrfs_key key; 536 u64 end_byte = bytenr + len; 537 u64 csum_end; 538 struct extent_buffer *leaf; 539 int ret; 540 u16 csum_size = 541 btrfs_super_csum_size(&root->fs_info->super_copy); 542 int blocksize_bits = root->fs_info->sb->s_blocksize_bits; 543 544 root = root->fs_info->csum_root; 545 546 path = btrfs_alloc_path(); 547 if (!path) 548 return -ENOMEM; 549 550 while (1) { 551 key.objectid = BTRFS_EXTENT_CSUM_OBJECTID; 552 key.offset = end_byte - 1; 553 key.type = BTRFS_EXTENT_CSUM_KEY; 554 555 path->leave_spinning = 1; 556 ret = btrfs_search_slot(trans, root, &key, path, -1, 1); 557 if (ret > 0) { 558 if (path->slots[0] == 0) 559 break; 560 path->slots[0]--; 561 } else if (ret < 0) { 562 break; 563 } 564 565 leaf = path->nodes[0]; 566 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]); 567 568 if (key.objectid != BTRFS_EXTENT_CSUM_OBJECTID || 569 key.type != BTRFS_EXTENT_CSUM_KEY) { 570 break; 571 } 572 573 if (key.offset >= end_byte) 574 break; 575 576 csum_end = btrfs_item_size_nr(leaf, path->slots[0]) / csum_size; 577 csum_end <<= blocksize_bits; 578 csum_end += key.offset; 579 580 /* this csum ends before we start, we're done */ 581 if (csum_end <= bytenr) 582 break; 583 584 /* delete the entire item, it is inside our range */ 585 if (key.offset >= bytenr && csum_end <= end_byte) { 586 ret = btrfs_del_item(trans, root, path); 587 if (ret) 588 goto out; 589 if (key.offset == bytenr) 590 break; 591 } else if (key.offset < bytenr && csum_end > end_byte) { 592 unsigned long offset; 593 unsigned long shift_len; 594 unsigned long item_offset; 595 /* 596 * [ bytenr - len ] 597 * [csum ] 598 * 599 * Our bytes are in the middle of the csum, 600 * we need to split this item and insert a new one. 601 * 602 * But we can't drop the path because the 603 * csum could change, get removed, extended etc. 604 * 605 * The trick here is the max size of a csum item leaves 606 * enough room in the tree block for a single 607 * item header. So, we split the item in place, 608 * adding a new header pointing to the existing 609 * bytes. Then we loop around again and we have 610 * a nicely formed csum item that we can neatly 611 * truncate. 612 */ 613 offset = (bytenr - key.offset) >> blocksize_bits; 614 offset *= csum_size; 615 616 shift_len = (len >> blocksize_bits) * csum_size; 617 618 item_offset = btrfs_item_ptr_offset(leaf, 619 path->slots[0]); 620 621 memset_extent_buffer(leaf, 0, item_offset + offset, 622 shift_len); 623 key.offset = bytenr; 624 625 /* 626 * btrfs_split_item returns -EAGAIN when the 627 * item changed size or key 628 */ 629 ret = btrfs_split_item(trans, root, path, &key, offset); 630 BUG_ON(ret && ret != -EAGAIN); 631 632 key.offset = end_byte - 1; 633 } else { 634 ret = truncate_one_csum(trans, root, path, 635 &key, bytenr, len); 636 BUG_ON(ret); 637 if (key.offset < bytenr) 638 break; 639 } 640 btrfs_release_path(path); 641 } 642 ret = 0; 643 out: 644 btrfs_free_path(path); 645 return ret; 646 } 647 648 int btrfs_csum_file_blocks(struct btrfs_trans_handle *trans, 649 struct btrfs_root *root, 650 struct btrfs_ordered_sum *sums) 651 { 652 u64 bytenr; 653 int ret; 654 struct btrfs_key file_key; 655 struct btrfs_key found_key; 656 u64 next_offset; 657 u64 total_bytes = 0; 658 int found_next; 659 struct btrfs_path *path; 660 struct btrfs_csum_item *item; 661 struct btrfs_csum_item *item_end; 662 struct extent_buffer *leaf = NULL; 663 u64 csum_offset; 664 struct btrfs_sector_sum *sector_sum; 665 u32 nritems; 666 u32 ins_size; 667 char *eb_map; 668 char *eb_token; 669 unsigned long map_len; 670 unsigned long map_start; 671 u16 csum_size = 672 btrfs_super_csum_size(&root->fs_info->super_copy); 673 674 path = btrfs_alloc_path(); 675 BUG_ON(!path); 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 ret = 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 eb_token = NULL; 818 next_sector: 819 820 if (!eb_token || 821 (unsigned long)item + csum_size >= map_start + map_len) { 822 int err; 823 824 if (eb_token) 825 unmap_extent_buffer(leaf, eb_token, KM_USER1); 826 eb_token = NULL; 827 err = map_private_extent_buffer(leaf, (unsigned long)item, 828 csum_size, 829 &eb_token, &eb_map, 830 &map_start, &map_len, KM_USER1); 831 if (err) 832 eb_token = NULL; 833 } 834 if (eb_token) { 835 memcpy(eb_token + ((unsigned long)item & (PAGE_CACHE_SIZE - 1)), 836 §or_sum->sum, csum_size); 837 } else { 838 write_extent_buffer(leaf, §or_sum->sum, 839 (unsigned long)item, csum_size); 840 } 841 842 total_bytes += root->sectorsize; 843 sector_sum++; 844 if (total_bytes < sums->len) { 845 item = (struct btrfs_csum_item *)((char *)item + 846 csum_size); 847 if (item < item_end && bytenr + PAGE_CACHE_SIZE == 848 sector_sum->bytenr) { 849 bytenr = sector_sum->bytenr; 850 goto next_sector; 851 } 852 } 853 if (eb_token) { 854 unmap_extent_buffer(leaf, eb_token, KM_USER1); 855 eb_token = NULL; 856 } 857 btrfs_mark_buffer_dirty(path->nodes[0]); 858 if (total_bytes < sums->len) { 859 btrfs_release_path(path); 860 cond_resched(); 861 goto again; 862 } 863 out: 864 btrfs_free_path(path); 865 return ret; 866 867 fail_unlock: 868 goto out; 869 } 870