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_CSUM_ITEMS(r, size) (min(__MAX_CSUM_ITEMS(r, size), PAGE_CACHE_SIZE)) 33 34 #define MAX_ORDERED_SUM_BYTES(r) ((PAGE_SIZE - \ 35 sizeof(struct btrfs_ordered_sum)) / \ 36 sizeof(struct btrfs_sector_sum) * \ 37 (r)->sectorsize - (r)->sectorsize) 38 39 int btrfs_insert_file_extent(struct btrfs_trans_handle *trans, 40 struct btrfs_root *root, 41 u64 objectid, u64 pos, 42 u64 disk_offset, u64 disk_num_bytes, 43 u64 num_bytes, u64 offset, u64 ram_bytes, 44 u8 compression, u8 encryption, u16 other_encoding) 45 { 46 int ret = 0; 47 struct btrfs_file_extent_item *item; 48 struct btrfs_key file_key; 49 struct btrfs_path *path; 50 struct extent_buffer *leaf; 51 52 path = btrfs_alloc_path(); 53 if (!path) 54 return -ENOMEM; 55 file_key.objectid = objectid; 56 file_key.offset = pos; 57 btrfs_set_key_type(&file_key, BTRFS_EXTENT_DATA_KEY); 58 59 path->leave_spinning = 1; 60 ret = btrfs_insert_empty_item(trans, root, path, &file_key, 61 sizeof(*item)); 62 if (ret < 0) 63 goto out; 64 BUG_ON(ret); /* Can't happen */ 65 leaf = path->nodes[0]; 66 item = btrfs_item_ptr(leaf, path->slots[0], 67 struct btrfs_file_extent_item); 68 btrfs_set_file_extent_disk_bytenr(leaf, item, disk_offset); 69 btrfs_set_file_extent_disk_num_bytes(leaf, item, disk_num_bytes); 70 btrfs_set_file_extent_offset(leaf, item, offset); 71 btrfs_set_file_extent_num_bytes(leaf, item, num_bytes); 72 btrfs_set_file_extent_ram_bytes(leaf, item, ram_bytes); 73 btrfs_set_file_extent_generation(leaf, item, trans->transid); 74 btrfs_set_file_extent_type(leaf, item, BTRFS_FILE_EXTENT_REG); 75 btrfs_set_file_extent_compression(leaf, item, compression); 76 btrfs_set_file_extent_encryption(leaf, item, encryption); 77 btrfs_set_file_extent_other_encoding(leaf, item, other_encoding); 78 79 btrfs_mark_buffer_dirty(leaf); 80 out: 81 btrfs_free_path(path); 82 return ret; 83 } 84 85 struct btrfs_csum_item *btrfs_lookup_csum(struct btrfs_trans_handle *trans, 86 struct btrfs_root *root, 87 struct btrfs_path *path, 88 u64 bytenr, int cow) 89 { 90 int ret; 91 struct btrfs_key file_key; 92 struct btrfs_key found_key; 93 struct btrfs_csum_item *item; 94 struct extent_buffer *leaf; 95 u64 csum_offset = 0; 96 u16 csum_size = btrfs_super_csum_size(root->fs_info->super_copy); 97 int csums_in_item; 98 99 file_key.objectid = BTRFS_EXTENT_CSUM_OBJECTID; 100 file_key.offset = bytenr; 101 btrfs_set_key_type(&file_key, BTRFS_EXTENT_CSUM_KEY); 102 ret = btrfs_search_slot(trans, root, &file_key, path, 0, cow); 103 if (ret < 0) 104 goto fail; 105 leaf = path->nodes[0]; 106 if (ret > 0) { 107 ret = 1; 108 if (path->slots[0] == 0) 109 goto fail; 110 path->slots[0]--; 111 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]); 112 if (btrfs_key_type(&found_key) != BTRFS_EXTENT_CSUM_KEY) 113 goto fail; 114 115 csum_offset = (bytenr - found_key.offset) >> 116 root->fs_info->sb->s_blocksize_bits; 117 csums_in_item = btrfs_item_size_nr(leaf, path->slots[0]); 118 csums_in_item /= csum_size; 119 120 if (csum_offset >= csums_in_item) { 121 ret = -EFBIG; 122 goto fail; 123 } 124 } 125 item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_csum_item); 126 item = (struct btrfs_csum_item *)((unsigned char *)item + 127 csum_offset * csum_size); 128 return item; 129 fail: 130 if (ret > 0) 131 ret = -ENOENT; 132 return ERR_PTR(ret); 133 } 134 135 136 int btrfs_lookup_file_extent(struct btrfs_trans_handle *trans, 137 struct btrfs_root *root, 138 struct btrfs_path *path, u64 objectid, 139 u64 offset, int mod) 140 { 141 int ret; 142 struct btrfs_key file_key; 143 int ins_len = mod < 0 ? -1 : 0; 144 int cow = mod != 0; 145 146 file_key.objectid = objectid; 147 file_key.offset = offset; 148 btrfs_set_key_type(&file_key, BTRFS_EXTENT_DATA_KEY); 149 ret = btrfs_search_slot(trans, root, &file_key, path, ins_len, cow); 150 return ret; 151 } 152 153 154 static int __btrfs_lookup_bio_sums(struct btrfs_root *root, 155 struct inode *inode, struct bio *bio, 156 u64 logical_offset, u32 *dst, int dio) 157 { 158 u32 sum; 159 struct bio_vec *bvec = bio->bi_io_vec; 160 int bio_index = 0; 161 u64 offset = 0; 162 u64 item_start_offset = 0; 163 u64 item_last_offset = 0; 164 u64 disk_bytenr; 165 u32 diff; 166 u16 csum_size = 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 /* 181 * the free space stuff is only read when it hasn't been 182 * updated in the current transaction. So, we can safely 183 * read from the commit root and sidestep a nasty deadlock 184 * between reading the free space cache and updating the csum tree. 185 */ 186 if (btrfs_is_free_space_inode(root, inode)) { 187 path->search_commit_root = 1; 188 path->skip_locking = 1; 189 } 190 191 disk_bytenr = (u64)bio->bi_sector << 9; 192 if (dio) 193 offset = logical_offset; 194 while (bio_index < bio->bi_vcnt) { 195 if (!dio) 196 offset = page_offset(bvec->bv_page) + bvec->bv_offset; 197 ret = btrfs_find_ordered_sum(inode, offset, disk_bytenr, &sum); 198 if (ret == 0) 199 goto found; 200 201 if (!item || disk_bytenr < item_start_offset || 202 disk_bytenr >= item_last_offset) { 203 struct btrfs_key found_key; 204 u32 item_size; 205 206 if (item) 207 btrfs_release_path(path); 208 item = btrfs_lookup_csum(NULL, root->fs_info->csum_root, 209 path, disk_bytenr, 0); 210 if (IS_ERR(item)) { 211 ret = PTR_ERR(item); 212 if (ret == -ENOENT || ret == -EFBIG) 213 ret = 0; 214 sum = 0; 215 if (BTRFS_I(inode)->root->root_key.objectid == 216 BTRFS_DATA_RELOC_TREE_OBJECTID) { 217 set_extent_bits(io_tree, offset, 218 offset + bvec->bv_len - 1, 219 EXTENT_NODATASUM, GFP_NOFS); 220 } else { 221 printk(KERN_INFO "btrfs no csum found " 222 "for inode %llu start %llu\n", 223 (unsigned long long) 224 btrfs_ino(inode), 225 (unsigned long long)offset); 226 } 227 item = NULL; 228 btrfs_release_path(path); 229 goto found; 230 } 231 btrfs_item_key_to_cpu(path->nodes[0], &found_key, 232 path->slots[0]); 233 234 item_start_offset = found_key.offset; 235 item_size = btrfs_item_size_nr(path->nodes[0], 236 path->slots[0]); 237 item_last_offset = item_start_offset + 238 (item_size / csum_size) * 239 root->sectorsize; 240 item = btrfs_item_ptr(path->nodes[0], path->slots[0], 241 struct btrfs_csum_item); 242 } 243 /* 244 * this byte range must be able to fit inside 245 * a single leaf so it will also fit inside a u32 246 */ 247 diff = disk_bytenr - item_start_offset; 248 diff = diff / root->sectorsize; 249 diff = diff * csum_size; 250 251 read_extent_buffer(path->nodes[0], &sum, 252 ((unsigned long)item) + diff, 253 csum_size); 254 found: 255 if (dst) 256 *dst++ = sum; 257 else 258 set_state_private(io_tree, offset, sum); 259 disk_bytenr += bvec->bv_len; 260 offset += bvec->bv_len; 261 bio_index++; 262 bvec++; 263 } 264 btrfs_free_path(path); 265 return 0; 266 } 267 268 int btrfs_lookup_bio_sums(struct btrfs_root *root, struct inode *inode, 269 struct bio *bio, u32 *dst) 270 { 271 return __btrfs_lookup_bio_sums(root, inode, bio, 0, dst, 0); 272 } 273 274 int btrfs_lookup_bio_sums_dio(struct btrfs_root *root, struct inode *inode, 275 struct bio *bio, u64 offset, u32 *dst) 276 { 277 return __btrfs_lookup_bio_sums(root, inode, bio, offset, dst, 1); 278 } 279 280 int btrfs_lookup_csums_range(struct btrfs_root *root, u64 start, u64 end, 281 struct list_head *list, int search_commit) 282 { 283 struct btrfs_key key; 284 struct btrfs_path *path; 285 struct extent_buffer *leaf; 286 struct btrfs_ordered_sum *sums; 287 struct btrfs_sector_sum *sector_sum; 288 struct btrfs_csum_item *item; 289 LIST_HEAD(tmplist); 290 unsigned long offset; 291 int ret; 292 size_t size; 293 u64 csum_end; 294 u16 csum_size = btrfs_super_csum_size(root->fs_info->super_copy); 295 296 path = btrfs_alloc_path(); 297 if (!path) 298 return -ENOMEM; 299 300 if (search_commit) { 301 path->skip_locking = 1; 302 path->reada = 2; 303 path->search_commit_root = 1; 304 } 305 306 key.objectid = BTRFS_EXTENT_CSUM_OBJECTID; 307 key.offset = start; 308 key.type = BTRFS_EXTENT_CSUM_KEY; 309 310 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0); 311 if (ret < 0) 312 goto fail; 313 if (ret > 0 && path->slots[0] > 0) { 314 leaf = path->nodes[0]; 315 btrfs_item_key_to_cpu(leaf, &key, path->slots[0] - 1); 316 if (key.objectid == BTRFS_EXTENT_CSUM_OBJECTID && 317 key.type == BTRFS_EXTENT_CSUM_KEY) { 318 offset = (start - key.offset) >> 319 root->fs_info->sb->s_blocksize_bits; 320 if (offset * csum_size < 321 btrfs_item_size_nr(leaf, path->slots[0] - 1)) 322 path->slots[0]--; 323 } 324 } 325 326 while (start <= end) { 327 leaf = path->nodes[0]; 328 if (path->slots[0] >= btrfs_header_nritems(leaf)) { 329 ret = btrfs_next_leaf(root, path); 330 if (ret < 0) 331 goto fail; 332 if (ret > 0) 333 break; 334 leaf = path->nodes[0]; 335 } 336 337 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]); 338 if (key.objectid != BTRFS_EXTENT_CSUM_OBJECTID || 339 key.type != BTRFS_EXTENT_CSUM_KEY) 340 break; 341 342 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]); 343 if (key.offset > end) 344 break; 345 346 if (key.offset > start) 347 start = key.offset; 348 349 size = btrfs_item_size_nr(leaf, path->slots[0]); 350 csum_end = key.offset + (size / csum_size) * root->sectorsize; 351 if (csum_end <= start) { 352 path->slots[0]++; 353 continue; 354 } 355 356 csum_end = min(csum_end, end + 1); 357 item = btrfs_item_ptr(path->nodes[0], path->slots[0], 358 struct btrfs_csum_item); 359 while (start < csum_end) { 360 size = min_t(size_t, csum_end - start, 361 MAX_ORDERED_SUM_BYTES(root)); 362 sums = kzalloc(btrfs_ordered_sum_size(root, size), 363 GFP_NOFS); 364 if (!sums) { 365 ret = -ENOMEM; 366 goto fail; 367 } 368 369 sector_sum = sums->sums; 370 sums->bytenr = start; 371 sums->len = size; 372 373 offset = (start - key.offset) >> 374 root->fs_info->sb->s_blocksize_bits; 375 offset *= csum_size; 376 377 while (size > 0) { 378 read_extent_buffer(path->nodes[0], 379 §or_sum->sum, 380 ((unsigned long)item) + 381 offset, csum_size); 382 sector_sum->bytenr = start; 383 384 size -= root->sectorsize; 385 start += root->sectorsize; 386 offset += csum_size; 387 sector_sum++; 388 } 389 list_add_tail(&sums->list, &tmplist); 390 } 391 path->slots[0]++; 392 } 393 ret = 0; 394 fail: 395 while (ret < 0 && !list_empty(&tmplist)) { 396 sums = list_entry(&tmplist, struct btrfs_ordered_sum, list); 397 list_del(&sums->list); 398 kfree(sums); 399 } 400 list_splice_tail(&tmplist, list); 401 402 btrfs_free_path(path); 403 return ret; 404 } 405 406 int btrfs_csum_one_bio(struct btrfs_root *root, struct inode *inode, 407 struct bio *bio, u64 file_start, int contig) 408 { 409 struct btrfs_ordered_sum *sums; 410 struct btrfs_sector_sum *sector_sum; 411 struct btrfs_ordered_extent *ordered; 412 char *data; 413 struct bio_vec *bvec = bio->bi_io_vec; 414 int bio_index = 0; 415 unsigned long total_bytes = 0; 416 unsigned long this_sum_bytes = 0; 417 u64 offset; 418 u64 disk_bytenr; 419 420 WARN_ON(bio->bi_vcnt <= 0); 421 sums = kzalloc(btrfs_ordered_sum_size(root, bio->bi_size), GFP_NOFS); 422 if (!sums) 423 return -ENOMEM; 424 425 sector_sum = sums->sums; 426 disk_bytenr = (u64)bio->bi_sector << 9; 427 sums->len = bio->bi_size; 428 INIT_LIST_HEAD(&sums->list); 429 430 if (contig) 431 offset = file_start; 432 else 433 offset = page_offset(bvec->bv_page) + bvec->bv_offset; 434 435 ordered = btrfs_lookup_ordered_extent(inode, offset); 436 BUG_ON(!ordered); /* Logic error */ 437 sums->bytenr = ordered->start; 438 439 while (bio_index < bio->bi_vcnt) { 440 if (!contig) 441 offset = page_offset(bvec->bv_page) + bvec->bv_offset; 442 443 if (!contig && (offset >= ordered->file_offset + ordered->len || 444 offset < ordered->file_offset)) { 445 unsigned long bytes_left; 446 sums->len = this_sum_bytes; 447 this_sum_bytes = 0; 448 btrfs_add_ordered_sum(inode, ordered, sums); 449 btrfs_put_ordered_extent(ordered); 450 451 bytes_left = bio->bi_size - total_bytes; 452 453 sums = kzalloc(btrfs_ordered_sum_size(root, bytes_left), 454 GFP_NOFS); 455 BUG_ON(!sums); /* -ENOMEM */ 456 sector_sum = sums->sums; 457 sums->len = bytes_left; 458 ordered = btrfs_lookup_ordered_extent(inode, offset); 459 BUG_ON(!ordered); /* Logic error */ 460 sums->bytenr = ordered->start; 461 } 462 463 data = kmap_atomic(bvec->bv_page); 464 sector_sum->sum = ~(u32)0; 465 sector_sum->sum = btrfs_csum_data(root, 466 data + bvec->bv_offset, 467 sector_sum->sum, 468 bvec->bv_len); 469 kunmap_atomic(data); 470 btrfs_csum_final(sector_sum->sum, 471 (char *)§or_sum->sum); 472 sector_sum->bytenr = disk_bytenr; 473 474 sector_sum++; 475 bio_index++; 476 total_bytes += bvec->bv_len; 477 this_sum_bytes += bvec->bv_len; 478 disk_bytenr += bvec->bv_len; 479 offset += bvec->bv_len; 480 bvec++; 481 } 482 this_sum_bytes = 0; 483 btrfs_add_ordered_sum(inode, ordered, sums); 484 btrfs_put_ordered_extent(ordered); 485 return 0; 486 } 487 488 /* 489 * helper function for csum removal, this expects the 490 * key to describe the csum pointed to by the path, and it expects 491 * the csum to overlap the range [bytenr, len] 492 * 493 * The csum should not be entirely contained in the range and the 494 * range should not be entirely contained in the csum. 495 * 496 * This calls btrfs_truncate_item with the correct args based on the 497 * overlap, and fixes up the key as required. 498 */ 499 static noinline void truncate_one_csum(struct btrfs_trans_handle *trans, 500 struct btrfs_root *root, 501 struct btrfs_path *path, 502 struct btrfs_key *key, 503 u64 bytenr, u64 len) 504 { 505 struct extent_buffer *leaf; 506 u16 csum_size = btrfs_super_csum_size(root->fs_info->super_copy); 507 u64 csum_end; 508 u64 end_byte = bytenr + len; 509 u32 blocksize_bits = root->fs_info->sb->s_blocksize_bits; 510 511 leaf = path->nodes[0]; 512 csum_end = btrfs_item_size_nr(leaf, path->slots[0]) / csum_size; 513 csum_end <<= root->fs_info->sb->s_blocksize_bits; 514 csum_end += key->offset; 515 516 if (key->offset < bytenr && csum_end <= end_byte) { 517 /* 518 * [ bytenr - len ] 519 * [ ] 520 * [csum ] 521 * A simple truncate off the end of the item 522 */ 523 u32 new_size = (bytenr - key->offset) >> blocksize_bits; 524 new_size *= csum_size; 525 btrfs_truncate_item(trans, root, path, new_size, 1); 526 } else if (key->offset >= bytenr && csum_end > end_byte && 527 end_byte > key->offset) { 528 /* 529 * [ bytenr - len ] 530 * [ ] 531 * [csum ] 532 * we need to truncate from the beginning of the csum 533 */ 534 u32 new_size = (csum_end - end_byte) >> blocksize_bits; 535 new_size *= csum_size; 536 537 btrfs_truncate_item(trans, root, path, new_size, 0); 538 539 key->offset = end_byte; 540 btrfs_set_item_key_safe(trans, root, path, key); 541 } else { 542 BUG(); 543 } 544 } 545 546 /* 547 * deletes the csum items from the csum tree for a given 548 * range of bytes. 549 */ 550 int btrfs_del_csums(struct btrfs_trans_handle *trans, 551 struct btrfs_root *root, u64 bytenr, u64 len) 552 { 553 struct btrfs_path *path; 554 struct btrfs_key key; 555 u64 end_byte = bytenr + len; 556 u64 csum_end; 557 struct extent_buffer *leaf; 558 int ret; 559 u16 csum_size = btrfs_super_csum_size(root->fs_info->super_copy); 560 int blocksize_bits = root->fs_info->sb->s_blocksize_bits; 561 562 root = root->fs_info->csum_root; 563 564 path = btrfs_alloc_path(); 565 if (!path) 566 return -ENOMEM; 567 568 while (1) { 569 key.objectid = BTRFS_EXTENT_CSUM_OBJECTID; 570 key.offset = end_byte - 1; 571 key.type = BTRFS_EXTENT_CSUM_KEY; 572 573 path->leave_spinning = 1; 574 ret = btrfs_search_slot(trans, root, &key, path, -1, 1); 575 if (ret > 0) { 576 if (path->slots[0] == 0) 577 break; 578 path->slots[0]--; 579 } else if (ret < 0) { 580 break; 581 } 582 583 leaf = path->nodes[0]; 584 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]); 585 586 if (key.objectid != BTRFS_EXTENT_CSUM_OBJECTID || 587 key.type != BTRFS_EXTENT_CSUM_KEY) { 588 break; 589 } 590 591 if (key.offset >= end_byte) 592 break; 593 594 csum_end = btrfs_item_size_nr(leaf, path->slots[0]) / csum_size; 595 csum_end <<= blocksize_bits; 596 csum_end += key.offset; 597 598 /* this csum ends before we start, we're done */ 599 if (csum_end <= bytenr) 600 break; 601 602 /* delete the entire item, it is inside our range */ 603 if (key.offset >= bytenr && csum_end <= end_byte) { 604 ret = btrfs_del_item(trans, root, path); 605 if (ret) 606 goto out; 607 if (key.offset == bytenr) 608 break; 609 } else if (key.offset < bytenr && csum_end > end_byte) { 610 unsigned long offset; 611 unsigned long shift_len; 612 unsigned long item_offset; 613 /* 614 * [ bytenr - len ] 615 * [csum ] 616 * 617 * Our bytes are in the middle of the csum, 618 * we need to split this item and insert a new one. 619 * 620 * But we can't drop the path because the 621 * csum could change, get removed, extended etc. 622 * 623 * The trick here is the max size of a csum item leaves 624 * enough room in the tree block for a single 625 * item header. So, we split the item in place, 626 * adding a new header pointing to the existing 627 * bytes. Then we loop around again and we have 628 * a nicely formed csum item that we can neatly 629 * truncate. 630 */ 631 offset = (bytenr - key.offset) >> blocksize_bits; 632 offset *= csum_size; 633 634 shift_len = (len >> blocksize_bits) * csum_size; 635 636 item_offset = btrfs_item_ptr_offset(leaf, 637 path->slots[0]); 638 639 memset_extent_buffer(leaf, 0, item_offset + offset, 640 shift_len); 641 key.offset = bytenr; 642 643 /* 644 * btrfs_split_item returns -EAGAIN when the 645 * item changed size or key 646 */ 647 ret = btrfs_split_item(trans, root, path, &key, offset); 648 if (ret && ret != -EAGAIN) { 649 btrfs_abort_transaction(trans, root, ret); 650 goto out; 651 } 652 653 key.offset = end_byte - 1; 654 } else { 655 truncate_one_csum(trans, root, path, &key, bytenr, len); 656 if (key.offset < bytenr) 657 break; 658 } 659 btrfs_release_path(path); 660 } 661 ret = 0; 662 out: 663 btrfs_free_path(path); 664 return ret; 665 } 666 667 int btrfs_csum_file_blocks(struct btrfs_trans_handle *trans, 668 struct btrfs_root *root, 669 struct btrfs_ordered_sum *sums) 670 { 671 u64 bytenr; 672 int ret; 673 struct btrfs_key file_key; 674 struct btrfs_key found_key; 675 u64 next_offset; 676 u64 total_bytes = 0; 677 int found_next; 678 struct btrfs_path *path; 679 struct btrfs_csum_item *item; 680 struct btrfs_csum_item *item_end; 681 struct extent_buffer *leaf = NULL; 682 u64 csum_offset; 683 struct btrfs_sector_sum *sector_sum; 684 u32 nritems; 685 u32 ins_size; 686 u16 csum_size = btrfs_super_csum_size(root->fs_info->super_copy); 687 688 path = btrfs_alloc_path(); 689 if (!path) 690 return -ENOMEM; 691 692 sector_sum = sums->sums; 693 again: 694 next_offset = (u64)-1; 695 found_next = 0; 696 file_key.objectid = BTRFS_EXTENT_CSUM_OBJECTID; 697 file_key.offset = sector_sum->bytenr; 698 bytenr = sector_sum->bytenr; 699 btrfs_set_key_type(&file_key, BTRFS_EXTENT_CSUM_KEY); 700 701 item = btrfs_lookup_csum(trans, root, path, sector_sum->bytenr, 1); 702 if (!IS_ERR(item)) { 703 leaf = path->nodes[0]; 704 ret = 0; 705 goto found; 706 } 707 ret = PTR_ERR(item); 708 if (ret != -EFBIG && ret != -ENOENT) 709 goto fail_unlock; 710 711 if (ret == -EFBIG) { 712 u32 item_size; 713 /* we found one, but it isn't big enough yet */ 714 leaf = path->nodes[0]; 715 item_size = btrfs_item_size_nr(leaf, path->slots[0]); 716 if ((item_size / csum_size) >= 717 MAX_CSUM_ITEMS(root, csum_size)) { 718 /* already at max size, make a new one */ 719 goto insert; 720 } 721 } else { 722 int slot = path->slots[0] + 1; 723 /* we didn't find a csum item, insert one */ 724 nritems = btrfs_header_nritems(path->nodes[0]); 725 if (path->slots[0] >= nritems - 1) { 726 ret = btrfs_next_leaf(root, path); 727 if (ret == 1) 728 found_next = 1; 729 if (ret != 0) 730 goto insert; 731 slot = 0; 732 } 733 btrfs_item_key_to_cpu(path->nodes[0], &found_key, slot); 734 if (found_key.objectid != BTRFS_EXTENT_CSUM_OBJECTID || 735 found_key.type != BTRFS_EXTENT_CSUM_KEY) { 736 found_next = 1; 737 goto insert; 738 } 739 next_offset = found_key.offset; 740 found_next = 1; 741 goto insert; 742 } 743 744 /* 745 * at this point, we know the tree has an item, but it isn't big 746 * enough yet to put our csum in. Grow it 747 */ 748 btrfs_release_path(path); 749 ret = btrfs_search_slot(trans, root, &file_key, path, 750 csum_size, 1); 751 if (ret < 0) 752 goto fail_unlock; 753 754 if (ret > 0) { 755 if (path->slots[0] == 0) 756 goto insert; 757 path->slots[0]--; 758 } 759 760 leaf = path->nodes[0]; 761 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]); 762 csum_offset = (bytenr - found_key.offset) >> 763 root->fs_info->sb->s_blocksize_bits; 764 765 if (btrfs_key_type(&found_key) != BTRFS_EXTENT_CSUM_KEY || 766 found_key.objectid != BTRFS_EXTENT_CSUM_OBJECTID || 767 csum_offset >= MAX_CSUM_ITEMS(root, csum_size)) { 768 goto insert; 769 } 770 771 if (csum_offset >= btrfs_item_size_nr(leaf, path->slots[0]) / 772 csum_size) { 773 u32 diff = (csum_offset + 1) * csum_size; 774 775 /* 776 * is the item big enough already? we dropped our lock 777 * before and need to recheck 778 */ 779 if (diff < btrfs_item_size_nr(leaf, path->slots[0])) 780 goto csum; 781 782 diff = diff - btrfs_item_size_nr(leaf, path->slots[0]); 783 if (diff != csum_size) 784 goto insert; 785 786 btrfs_extend_item(trans, root, path, diff); 787 goto csum; 788 } 789 790 insert: 791 btrfs_release_path(path); 792 csum_offset = 0; 793 if (found_next) { 794 u64 tmp = total_bytes + root->sectorsize; 795 u64 next_sector = sector_sum->bytenr; 796 struct btrfs_sector_sum *next = sector_sum + 1; 797 798 while (tmp < sums->len) { 799 if (next_sector + root->sectorsize != next->bytenr) 800 break; 801 tmp += root->sectorsize; 802 next_sector = next->bytenr; 803 next++; 804 } 805 tmp = min(tmp, next_offset - file_key.offset); 806 tmp >>= root->fs_info->sb->s_blocksize_bits; 807 tmp = max((u64)1, tmp); 808 tmp = min(tmp, (u64)MAX_CSUM_ITEMS(root, csum_size)); 809 ins_size = csum_size * tmp; 810 } else { 811 ins_size = csum_size; 812 } 813 path->leave_spinning = 1; 814 ret = btrfs_insert_empty_item(trans, root, path, &file_key, 815 ins_size); 816 path->leave_spinning = 0; 817 if (ret < 0) 818 goto fail_unlock; 819 if (ret != 0) { 820 WARN_ON(1); 821 goto fail_unlock; 822 } 823 csum: 824 leaf = path->nodes[0]; 825 item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_csum_item); 826 ret = 0; 827 item = (struct btrfs_csum_item *)((unsigned char *)item + 828 csum_offset * csum_size); 829 found: 830 item_end = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_csum_item); 831 item_end = (struct btrfs_csum_item *)((unsigned char *)item_end + 832 btrfs_item_size_nr(leaf, path->slots[0])); 833 next_sector: 834 835 write_extent_buffer(leaf, §or_sum->sum, (unsigned long)item, csum_size); 836 837 total_bytes += root->sectorsize; 838 sector_sum++; 839 if (total_bytes < sums->len) { 840 item = (struct btrfs_csum_item *)((char *)item + 841 csum_size); 842 if (item < item_end && bytenr + PAGE_CACHE_SIZE == 843 sector_sum->bytenr) { 844 bytenr = sector_sum->bytenr; 845 goto next_sector; 846 } 847 } 848 849 btrfs_mark_buffer_dirty(path->nodes[0]); 850 if (total_bytes < sums->len) { 851 btrfs_release_path(path); 852 cond_resched(); 853 goto again; 854 } 855 out: 856 btrfs_free_path(path); 857 return ret; 858 859 fail_unlock: 860 goto out; 861 } 862