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