1 /* 2 * linux/fs/jbd2/recovery.c 3 * 4 * Written by Stephen C. Tweedie <sct (at) redhat.com>, 1999 5 * 6 * Copyright 1999-2000 Red Hat Software --- All Rights Reserved 7 * 8 * This file is part of the Linux kernel and is made available under 9 * the terms of the GNU General Public License, version 2, or at your 10 * option, any later version, incorporated herein by reference. 11 * 12 * Journal recovery routines for the generic filesystem journaling code; 13 * part of the ext2fs journaling system. 14 */ 15 16 #ifndef __KERNEL__ 17 #include "jfs_user.h" 18 #else 19 #include <linux/time.h> 20 #include <linux/fs.h> 21 #include <linux/jbd2.h> 22 #include <linux/errno.h> 23 #include <linux/crc32.h> 24 #include <linux/blkdev.h> 25 #endif 26 27 /* 28 * Maintain information about the progress of the recovery job, so that 29 * the different passes can carry information between them. 30 */ 31 struct recovery_info 32 { 33 tid_t start_transaction; 34 tid_t end_transaction; 35 36 int nr_replays; 37 int nr_revokes; 38 int nr_revoke_hits; 39 }; 40 41 enum passtype {PASS_SCAN, PASS_REVOKE, PASS_REPLAY}; 42 static int do_one_pass(journal_t *journal, 43 struct recovery_info *info, enum passtype pass); 44 static int scan_revoke_records(journal_t *, struct buffer_head *, 45 tid_t, struct recovery_info *); 46 47 #ifdef __KERNEL__ 48 49 /* Release readahead buffers after use */ 50 static void journal_brelse_array(struct buffer_head *b[], int n) 51 { 52 while (--n >= 0) 53 brelse (b[n]); 54 } 55 56 57 /* 58 * When reading from the journal, we are going through the block device 59 * layer directly and so there is no readahead being done for us. We 60 * need to implement any readahead ourselves if we want it to happen at 61 * all. Recovery is basically one long sequential read, so make sure we 62 * do the IO in reasonably large chunks. 63 * 64 * This is not so critical that we need to be enormously clever about 65 * the readahead size, though. 128K is a purely arbitrary, good-enough 66 * fixed value. 67 */ 68 69 #define MAXBUF 8 70 static int do_readahead(journal_t *journal, unsigned int start) 71 { 72 int err; 73 unsigned int max, nbufs, next; 74 unsigned long long blocknr; 75 struct buffer_head *bh; 76 77 struct buffer_head * bufs[MAXBUF]; 78 79 /* Do up to 128K of readahead */ 80 max = start + (128 * 1024 / journal->j_blocksize); 81 if (max > journal->j_maxlen) 82 max = journal->j_maxlen; 83 84 /* Do the readahead itself. We'll submit MAXBUF buffer_heads at 85 * a time to the block device IO layer. */ 86 87 nbufs = 0; 88 89 for (next = start; next < max; next++) { 90 err = journal_bmap(journal, next, &blocknr); 91 92 if (err) { 93 printk(KERN_ERR "JBD2: bad block at offset %u\n", 94 next); 95 goto failed; 96 } 97 98 bh = __getblk(journal->j_dev, blocknr, journal->j_blocksize); 99 if (!bh) { 100 err = -ENOMEM; 101 goto failed; 102 } 103 104 if (!buffer_uptodate(bh) && !buffer_locked(bh)) { 105 bufs[nbufs++] = bh; 106 if (nbufs == MAXBUF) { 107 ll_rw_block(READ, nbufs, bufs); 108 journal_brelse_array(bufs, nbufs); 109 nbufs = 0; 110 } 111 } else 112 brelse(bh); 113 } 114 115 if (nbufs) 116 ll_rw_block(READ, nbufs, bufs); 117 err = 0; 118 119 failed: 120 if (nbufs) 121 journal_brelse_array(bufs, nbufs); 122 return err; 123 } 124 125 #endif /* __KERNEL__ */ 126 127 128 /* 129 * Read a block from the journal 130 */ 131 132 static int jread(struct buffer_head **bhp, journal_t *journal, 133 unsigned int offset) 134 { 135 int err; 136 unsigned long long blocknr; 137 struct buffer_head *bh; 138 139 *bhp = NULL; 140 141 if (offset >= journal->j_maxlen) { 142 printk(KERN_ERR "JBD2: corrupted journal superblock\n"); 143 return -EFSCORRUPTED; 144 } 145 146 err = journal_bmap(journal, offset, &blocknr); 147 148 if (err) { 149 printk(KERN_ERR "JBD2: bad block at offset %u\n", 150 offset); 151 return err; 152 } 153 154 bh = __getblk(journal->j_dev, blocknr, journal->j_blocksize); 155 if (!bh) 156 return -ENOMEM; 157 158 if (!buffer_uptodate(bh)) { 159 /* If this is a brand new buffer, start readahead. 160 Otherwise, we assume we are already reading it. */ 161 if (!buffer_req(bh)) 162 do_readahead(journal, offset); 163 wait_on_buffer(bh); 164 } 165 166 if (!buffer_uptodate(bh)) { 167 printk(KERN_ERR "JBD2: Failed to read block at offset %u\n", 168 offset); 169 brelse(bh); 170 return -EIO; 171 } 172 173 *bhp = bh; 174 return 0; 175 } 176 177 static int jbd2_descr_block_csum_verify(journal_t *j, 178 void *buf) 179 { 180 struct journal_block_tail *tail; 181 __u32 provided; 182 __u32 calculated; 183 184 if (!journal_has_csum_v2or3(j)) 185 return 1; 186 187 tail = (struct journal_block_tail *)((char *)buf + j->j_blocksize - 188 sizeof(struct journal_block_tail)); 189 provided = tail->t_checksum; 190 tail->t_checksum = 0; 191 calculated = jbd2_chksum(j, j->j_csum_seed, buf, j->j_blocksize); 192 tail->t_checksum = provided; 193 194 return provided == ext2fs_cpu_to_be32(calculated); 195 } 196 197 /* 198 * Count the number of in-use tags in a journal descriptor block. 199 */ 200 201 static int count_tags(journal_t *journal, struct buffer_head *bh) 202 { 203 char * tagp; 204 journal_block_tag_t * tag; 205 int nr = 0, size = journal->j_blocksize; 206 int tag_bytes = journal_tag_bytes(journal); 207 208 if (journal_has_csum_v2or3(journal)) 209 size -= sizeof(struct journal_block_tail); 210 211 tagp = &bh->b_data[sizeof(journal_header_t)]; 212 213 while ((tagp - bh->b_data + tag_bytes) <= size) { 214 tag = (journal_block_tag_t *) tagp; 215 216 nr++; 217 tagp += tag_bytes; 218 if (!(tag->t_flags & ext2fs_cpu_to_be16(JFS_FLAG_SAME_UUID))) 219 tagp += 16; 220 221 if (tag->t_flags & ext2fs_cpu_to_be16(JFS_FLAG_LAST_TAG)) 222 break; 223 } 224 225 return nr; 226 } 227 228 229 /* Make sure we wrap around the log correctly! */ 230 #define wrap(journal, var) \ 231 do { \ 232 if (var >= (journal)->j_last) \ 233 var -= ((journal)->j_last - (journal)->j_first); \ 234 } while (0) 235 236 /** 237 * journal_recover - recovers a on-disk journal 238 * @journal: the journal to recover 239 * 240 * The primary function for recovering the log contents when mounting a 241 * journaled device. 242 * 243 * Recovery is done in three passes. In the first pass, we look for the 244 * end of the log. In the second, we assemble the list of revoke 245 * blocks. In the third and final pass, we replay any un-revoked blocks 246 * in the log. 247 */ 248 int journal_recover(journal_t *journal) 249 { 250 int err, err2; 251 journal_superblock_t * sb; 252 253 struct recovery_info info; 254 255 memset(&info, 0, sizeof(info)); 256 sb = journal->j_superblock; 257 258 /* 259 * The journal superblock's s_start field (the current log head) 260 * is always zero if, and only if, the journal was cleanly 261 * unmounted. 262 */ 263 264 if (!sb->s_start) { 265 jbd_debug(1, "No recovery required, last transaction %d\n", 266 ext2fs_be32_to_cpu(sb->s_sequence)); 267 journal->j_transaction_sequence = ext2fs_be32_to_cpu(sb->s_sequence) + 1; 268 return 0; 269 } 270 271 err = do_one_pass(journal, &info, PASS_SCAN); 272 if (!err) 273 err = do_one_pass(journal, &info, PASS_REVOKE); 274 if (!err) 275 err = do_one_pass(journal, &info, PASS_REPLAY); 276 277 jbd_debug(1, "JBD2: recovery, exit status %d, " 278 "recovered transactions %u to %u\n", 279 err, info.start_transaction, info.end_transaction); 280 jbd_debug(1, "JBD2: Replayed %d and revoked %d/%d blocks\n", 281 info.nr_replays, info.nr_revoke_hits, info.nr_revokes); 282 283 /* Restart the log at the next transaction ID, thus invalidating 284 * any existing commit records in the log. */ 285 journal->j_transaction_sequence = ++info.end_transaction; 286 287 journal_clear_revoke(journal); 288 err2 = sync_blockdev(journal->j_fs_dev); 289 if (!err) 290 err = err2; 291 /* Make sure all replayed data is on permanent storage */ 292 if (journal->j_flags & JFS_BARRIER) { 293 err2 = blkdev_issue_flush(journal->j_fs_dev, GFP_KERNEL, NULL); 294 if (!err) 295 err = err2; 296 } 297 return err; 298 } 299 300 /** 301 * journal_skip_recovery - Start journal and wipe exiting records 302 * @journal: journal to startup 303 * 304 * Locate any valid recovery information from the journal and set up the 305 * journal structures in memory to ignore it (presumably because the 306 * caller has evidence that it is out of date). 307 * This function does'nt appear to be exorted.. 308 * 309 * We perform one pass over the journal to allow us to tell the user how 310 * much recovery information is being erased, and to let us initialise 311 * the journal transaction sequence numbers to the next unused ID. 312 */ 313 int journal_skip_recovery(journal_t *journal) 314 { 315 int err; 316 317 struct recovery_info info; 318 319 memset (&info, 0, sizeof(info)); 320 321 err = do_one_pass(journal, &info, PASS_SCAN); 322 323 if (err) { 324 printk(KERN_ERR "JBD2: error %d scanning journal\n", err); 325 ++journal->j_transaction_sequence; 326 } else { 327 #ifdef CONFIG_JFS_DEBUG 328 int dropped = info.end_transaction - 329 ext2fs_be32_to_cpu(journal->j_superblock->s_sequence); 330 jbd_debug(1, 331 "JBD2: ignoring %d transaction%s from the journal.\n", 332 dropped, (dropped == 1) ? "" : "s"); 333 #endif 334 journal->j_transaction_sequence = ++info.end_transaction; 335 } 336 337 journal->j_tail = 0; 338 return err; 339 } 340 341 static inline __u32 get_be32(__be32 *p) 342 { 343 unsigned char *cp = (unsigned char *) p; 344 __u32 ret; 345 346 ret = *cp++; 347 ret = (ret << 8) + *cp++; 348 ret = (ret << 8) + *cp++; 349 ret = (ret << 8) + *cp++; 350 return ret; 351 } 352 353 static inline unsigned long long read_tag_block(journal_t *journal, 354 journal_block_tag_t *tag) 355 { 356 unsigned long long block = get_be32(&tag->t_blocknr); 357 if (jfs_has_feature_64bit(journal)) 358 block |= (u64)get_be32(&tag->t_blocknr_high) << 32; 359 return block; 360 } 361 362 /* 363 * calc_chksums calculates the checksums for the blocks described in the 364 * descriptor block. 365 */ 366 static int calc_chksums(journal_t *journal, struct buffer_head *bh, 367 unsigned long *next_log_block, __u32 *crc32_sum) 368 { 369 int i, num_blks, err; 370 unsigned long io_block; 371 struct buffer_head *obh; 372 373 num_blks = count_tags(journal, bh); 374 /* Calculate checksum of the descriptor block. */ 375 *crc32_sum = crc32_be(*crc32_sum, (void *)bh->b_data, bh->b_size); 376 377 for (i = 0; i < num_blks; i++) { 378 io_block = (*next_log_block)++; 379 wrap(journal, *next_log_block); 380 err = jread(&obh, journal, io_block); 381 if (err) { 382 printk(KERN_ERR "JBD2: IO error %d recovering block " 383 "%lu in log\n", err, io_block); 384 return 1; 385 } else { 386 *crc32_sum = crc32_be(*crc32_sum, (void *)obh->b_data, 387 obh->b_size); 388 } 389 put_bh(obh); 390 } 391 return 0; 392 } 393 394 static int jbd2_commit_block_csum_verify(journal_t *j, void *buf) 395 { 396 struct commit_header *h; 397 __u32 provided; 398 __u32 calculated; 399 400 if (!journal_has_csum_v2or3(j)) 401 return 1; 402 403 h = buf; 404 provided = h->h_chksum[0]; 405 h->h_chksum[0] = 0; 406 calculated = jbd2_chksum(j, j->j_csum_seed, buf, j->j_blocksize); 407 h->h_chksum[0] = provided; 408 409 return provided == ext2fs_cpu_to_be32(calculated); 410 } 411 412 static int jbd2_block_tag_csum_verify(journal_t *j, journal_block_tag_t *tag, 413 void *buf, __u32 sequence) 414 { 415 journal_block_tag3_t *tag3 = (journal_block_tag3_t *)tag; 416 __u32 csum32; 417 __u32 seq; 418 419 if (!journal_has_csum_v2or3(j)) 420 return 1; 421 422 seq = ext2fs_cpu_to_be32(sequence); 423 csum32 = jbd2_chksum(j, j->j_csum_seed, (__u8 *)&seq, sizeof(seq)); 424 csum32 = jbd2_chksum(j, csum32, buf, j->j_blocksize); 425 426 if (jfs_has_feature_csum3(j)) 427 return tag3->t_checksum == ext2fs_cpu_to_be32(csum32); 428 429 return tag->t_checksum == ext2fs_cpu_to_be16(csum32); 430 } 431 432 static int do_one_pass(journal_t *journal, 433 struct recovery_info *info, enum passtype pass) 434 { 435 unsigned int first_commit_ID, next_commit_ID; 436 unsigned long next_log_block; 437 int err, success = 0; 438 journal_superblock_t * sb; 439 journal_header_t * tmp; 440 struct buffer_head * bh; 441 unsigned int sequence; 442 int blocktype; 443 int tag_bytes = journal_tag_bytes(journal); 444 __u32 crc32_sum = ~0; /* Transactional Checksums */ 445 int descr_csum_size = 0; 446 int block_error = 0; 447 448 /* 449 * First thing is to establish what we expect to find in the log 450 * (in terms of transaction IDs), and where (in terms of log 451 * block offsets): query the superblock. 452 */ 453 454 sb = journal->j_superblock; 455 next_commit_ID = ext2fs_be32_to_cpu(sb->s_sequence); 456 next_log_block = ext2fs_be32_to_cpu(sb->s_start); 457 458 first_commit_ID = next_commit_ID; 459 if (pass == PASS_SCAN) 460 info->start_transaction = first_commit_ID; 461 462 jbd_debug(1, "Starting recovery pass %d\n", pass); 463 464 /* 465 * Now we walk through the log, transaction by transaction, 466 * making sure that each transaction has a commit block in the 467 * expected place. Each complete transaction gets replayed back 468 * into the main filesystem. 469 */ 470 471 while (1) { 472 int flags; 473 char * tagp; 474 journal_block_tag_t * tag; 475 struct buffer_head * obh; 476 struct buffer_head * nbh; 477 478 cond_resched(); 479 480 /* If we already know where to stop the log traversal, 481 * check right now that we haven't gone past the end of 482 * the log. */ 483 484 if (pass != PASS_SCAN) 485 if (tid_geq(next_commit_ID, info->end_transaction)) 486 break; 487 488 jbd_debug(2, "Scanning for sequence ID %u at %lu/%lu\n", 489 next_commit_ID, next_log_block, journal->j_last); 490 491 /* Skip over each chunk of the transaction looking 492 * either the next descriptor block or the final commit 493 * record. */ 494 495 jbd_debug(3, "JBD2: checking block %ld\n", next_log_block); 496 err = jread(&bh, journal, next_log_block); 497 if (err) 498 goto failed; 499 500 next_log_block++; 501 wrap(journal, next_log_block); 502 503 /* What kind of buffer is it? 504 * 505 * If it is a descriptor block, check that it has the 506 * expected sequence number. Otherwise, we're all done 507 * here. */ 508 509 tmp = (journal_header_t *)bh->b_data; 510 511 if (tmp->h_magic != ext2fs_cpu_to_be32(JFS_MAGIC_NUMBER)) { 512 brelse(bh); 513 break; 514 } 515 516 blocktype = ext2fs_be32_to_cpu(tmp->h_blocktype); 517 sequence = ext2fs_be32_to_cpu(tmp->h_sequence); 518 jbd_debug(3, "Found magic %d, sequence %d\n", 519 blocktype, sequence); 520 521 if (sequence != next_commit_ID) { 522 brelse(bh); 523 break; 524 } 525 526 /* OK, we have a valid descriptor block which matches 527 * all of the sequence number checks. What are we going 528 * to do with it? That depends on the pass... */ 529 530 switch(blocktype) { 531 case JFS_DESCRIPTOR_BLOCK: 532 /* Verify checksum first */ 533 if (journal_has_csum_v2or3(journal)) 534 descr_csum_size = 535 sizeof(struct journal_block_tail); 536 if (descr_csum_size > 0 && 537 !jbd2_descr_block_csum_verify(journal, 538 bh->b_data)) { 539 err = -EFSBADCRC; 540 brelse(bh); 541 goto failed; 542 } 543 544 /* If it is a valid descriptor block, replay it 545 * in pass REPLAY; if journal_checksums enabled, then 546 * calculate checksums in PASS_SCAN, otherwise, 547 * just skip over the blocks it describes. */ 548 if (pass != PASS_REPLAY) { 549 if (pass == PASS_SCAN && 550 jfs_has_feature_checksum(journal) && 551 !info->end_transaction) { 552 if (calc_chksums(journal, bh, 553 &next_log_block, 554 &crc32_sum)) { 555 put_bh(bh); 556 break; 557 } 558 put_bh(bh); 559 continue; 560 } 561 next_log_block += count_tags(journal, bh); 562 wrap(journal, next_log_block); 563 put_bh(bh); 564 continue; 565 } 566 567 /* A descriptor block: we can now write all of 568 * the data blocks. Yay, useful work is finally 569 * getting done here! */ 570 571 tagp = &bh->b_data[sizeof(journal_header_t)]; 572 while ((tagp - bh->b_data + tag_bytes) 573 <= journal->j_blocksize - descr_csum_size) { 574 unsigned long io_block; 575 576 tag = (journal_block_tag_t *) tagp; 577 flags = ext2fs_be16_to_cpu(tag->t_flags); 578 579 io_block = next_log_block++; 580 wrap(journal, next_log_block); 581 err = jread(&obh, journal, io_block); 582 if (err) { 583 /* Recover what we can, but 584 * report failure at the end. */ 585 success = err; 586 printk(KERN_ERR 587 "JBD2: IO error %d recovering " 588 "block %ld in log\n", 589 err, io_block); 590 } else { 591 unsigned long long blocknr; 592 593 J_ASSERT(obh != NULL); 594 blocknr = read_tag_block(journal, 595 tag); 596 597 /* If the block has been 598 * revoked, then we're all done 599 * here. */ 600 if (journal_test_revoke 601 (journal, blocknr, 602 next_commit_ID)) { 603 brelse(obh); 604 ++info->nr_revoke_hits; 605 goto skip_write; 606 } 607 608 /* Look for block corruption */ 609 if (!jbd2_block_tag_csum_verify( 610 journal, tag, obh->b_data, 611 ext2fs_be32_to_cpu(tmp->h_sequence))) { 612 brelse(obh); 613 success = -EFSBADCRC; 614 printk(KERN_ERR "JBD2: Invalid " 615 "checksum recovering " 616 "block %llu in log\n", 617 blocknr); 618 block_error = 1; 619 goto skip_write; 620 } 621 622 /* Find a buffer for the new 623 * data being restored */ 624 nbh = __getblk(journal->j_fs_dev, 625 blocknr, 626 journal->j_blocksize); 627 if (nbh == NULL) { 628 printk(KERN_ERR 629 "JBD2: Out of memory " 630 "during recovery.\n"); 631 err = -ENOMEM; 632 brelse(bh); 633 brelse(obh); 634 goto failed; 635 } 636 637 lock_buffer(nbh); 638 memcpy(nbh->b_data, obh->b_data, 639 journal->j_blocksize); 640 if (flags & JFS_FLAG_ESCAPE) { 641 __u32 magic = ext2fs_cpu_to_be32(JFS_MAGIC_NUMBER); 642 memcpy(nbh->b_data, &magic, 643 sizeof(magic)); 644 } 645 646 BUFFER_TRACE(nbh, "marking dirty"); 647 set_buffer_uptodate(nbh); 648 mark_buffer_dirty(nbh); 649 BUFFER_TRACE(nbh, "marking uptodate"); 650 ++info->nr_replays; 651 /* ll_rw_block(WRITE, 1, &nbh); */ 652 unlock_buffer(nbh); 653 brelse(obh); 654 brelse(nbh); 655 } 656 657 skip_write: 658 tagp += tag_bytes; 659 if (!(flags & JFS_FLAG_SAME_UUID)) 660 tagp += 16; 661 662 if (flags & JFS_FLAG_LAST_TAG) 663 break; 664 } 665 666 brelse(bh); 667 continue; 668 669 case JFS_COMMIT_BLOCK: 670 /* How to differentiate between interrupted commit 671 * and journal corruption ? 672 * 673 * {nth transaction} 674 * Checksum Verification Failed 675 * | 676 * ____________________ 677 * | | 678 * async_commit sync_commit 679 * | | 680 * | GO TO NEXT "Journal Corruption" 681 * | TRANSACTION 682 * | 683 * {(n+1)th transanction} 684 * | 685 * _______|______________ 686 * | | 687 * Commit block found Commit block not found 688 * | | 689 * "Journal Corruption" | 690 * _____________|_________ 691 * | | 692 * nth trans corrupt OR nth trans 693 * and (n+1)th interrupted interrupted 694 * before commit block 695 * could reach the disk. 696 * (Cannot find the difference in above 697 * mentioned conditions. Hence assume 698 * "Interrupted Commit".) 699 */ 700 701 /* Found an expected commit block: if checksums 702 * are present verify them in PASS_SCAN; else not 703 * much to do other than move on to the next sequence 704 * number. */ 705 if (pass == PASS_SCAN && 706 jfs_has_feature_checksum(journal)) { 707 int chksum_err, chksum_seen; 708 struct commit_header *cbh = 709 (struct commit_header *)bh->b_data; 710 unsigned found_chksum = 711 ext2fs_be32_to_cpu(cbh->h_chksum[0]); 712 713 chksum_err = chksum_seen = 0; 714 715 if (info->end_transaction) { 716 journal->j_failed_commit = 717 info->end_transaction; 718 brelse(bh); 719 break; 720 } 721 722 if (crc32_sum == found_chksum && 723 cbh->h_chksum_type == JFS_CRC32_CHKSUM && 724 cbh->h_chksum_size == 725 JFS_CRC32_CHKSUM_SIZE) 726 chksum_seen = 1; 727 else if (!(cbh->h_chksum_type == 0 && 728 cbh->h_chksum_size == 0 && 729 found_chksum == 0 && 730 !chksum_seen)) 731 /* 732 * If fs is mounted using an old kernel and then 733 * kernel with journal_chksum is used then we 734 * get a situation where the journal flag has 735 * checksum flag set but checksums are not 736 * present i.e chksum = 0, in the individual 737 * commit blocks. 738 * Hence to avoid checksum failures, in this 739 * situation, this extra check is added. 740 */ 741 chksum_err = 1; 742 743 if (chksum_err) { 744 info->end_transaction = next_commit_ID; 745 746 if (!jfs_has_feature_async_commit(journal)){ 747 journal->j_failed_commit = 748 next_commit_ID; 749 brelse(bh); 750 break; 751 } 752 } 753 crc32_sum = ~0; 754 } 755 if (pass == PASS_SCAN && 756 !jbd2_commit_block_csum_verify(journal, 757 bh->b_data)) { 758 info->end_transaction = next_commit_ID; 759 760 if (!jfs_has_feature_async_commit(journal)) { 761 journal->j_failed_commit = 762 next_commit_ID; 763 brelse(bh); 764 break; 765 } 766 } 767 brelse(bh); 768 next_commit_ID++; 769 continue; 770 771 case JFS_REVOKE_BLOCK: 772 /* If we aren't in the REVOKE pass, then we can 773 * just skip over this block. */ 774 if (pass != PASS_REVOKE) { 775 brelse(bh); 776 continue; 777 } 778 779 err = scan_revoke_records(journal, bh, 780 next_commit_ID, info); 781 brelse(bh); 782 if (err) 783 goto failed; 784 continue; 785 786 default: 787 jbd_debug(3, "Unrecognised magic %d, end of scan.\n", 788 blocktype); 789 brelse(bh); 790 goto done; 791 } 792 } 793 794 done: 795 /* 796 * We broke out of the log scan loop: either we came to the 797 * known end of the log or we found an unexpected block in the 798 * log. If the latter happened, then we know that the "current" 799 * transaction marks the end of the valid log. 800 */ 801 802 if (pass == PASS_SCAN) { 803 if (!info->end_transaction) 804 info->end_transaction = next_commit_ID; 805 } else { 806 /* It's really bad news if different passes end up at 807 * different places (but possible due to IO errors). */ 808 if (info->end_transaction != next_commit_ID) { 809 printk(KERN_ERR "JBD2: recovery pass %d ended at " 810 "transaction %u, expected %u\n", 811 pass, next_commit_ID, info->end_transaction); 812 if (!success) 813 success = -EIO; 814 } 815 } 816 if (block_error && success == 0) 817 success = -EIO; 818 return success; 819 820 failed: 821 return err; 822 } 823 824 static int jbd2_revoke_block_csum_verify(journal_t *j, 825 void *buf) 826 { 827 struct journal_revoke_tail *tail; 828 __u32 provided; 829 __u32 calculated; 830 831 if (!journal_has_csum_v2or3(j)) 832 return 1; 833 834 tail = (struct journal_revoke_tail *)((char *)buf + j->j_blocksize - 835 sizeof(struct journal_revoke_tail)); 836 provided = tail->r_checksum; 837 tail->r_checksum = 0; 838 calculated = jbd2_chksum(j, j->j_csum_seed, buf, j->j_blocksize); 839 tail->r_checksum = provided; 840 841 return provided == ext2fs_cpu_to_be32(calculated); 842 } 843 844 /* Scan a revoke record, marking all blocks mentioned as revoked. */ 845 846 static int scan_revoke_records(journal_t *journal, struct buffer_head *bh, 847 tid_t sequence, struct recovery_info *info) 848 { 849 journal_revoke_header_t *header; 850 int offset, max; 851 unsigned csum_size = 0; 852 __u32 rcount; 853 int record_len = 4; 854 855 header = (journal_revoke_header_t *) bh->b_data; 856 offset = sizeof(journal_revoke_header_t); 857 rcount = ext2fs_be32_to_cpu(header->r_count); 858 859 if (!jbd2_revoke_block_csum_verify(journal, header)) 860 return -EFSBADCRC; 861 862 if (journal_has_csum_v2or3(journal)) 863 csum_size = sizeof(struct journal_revoke_tail); 864 if (rcount > journal->j_blocksize - csum_size) 865 return -EINVAL; 866 max = rcount; 867 868 if (jfs_has_feature_64bit(journal)) 869 record_len = 8; 870 871 while (offset + record_len <= max) { 872 unsigned long long blocknr; 873 int err; 874 875 if (record_len == 4) 876 blocknr = ext2fs_be32_to_cpu(* ((__u32 *) (bh->b_data+offset))); 877 else 878 blocknr = ext2fs_be64_to_cpu(* ((__u64 *) (bh->b_data+offset))); 879 offset += record_len; 880 err = journal_set_revoke(journal, blocknr, sequence); 881 if (err) 882 return err; 883 ++info->nr_revokes; 884 } 885 return 0; 886 } 887
