recovery.c revision c10700f9748e54748f88a22554da3dca4b7fc234
1/* 2 * linux/fs/jbd2/recovery.c 3 * 4 * Written by Stephen C. Tweedie <sct@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 */ 31struct 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 41enum passtype {PASS_SCAN, PASS_REVOKE, PASS_REPLAY}; 42static int do_one_pass(journal_t *journal, 43 struct recovery_info *info, enum passtype pass); 44static 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 */ 50static 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 70static 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 119failed: 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 132static 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 -EIO; 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 177static 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 *)(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 201static 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) \ 231do { \ 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 */ 248int 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 */ 313int 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 341static inline unsigned long long read_tag_block(journal_t *journal, 342 journal_block_tag_t *tag) 343{ 344 unsigned long long block = ext2fs_be32_to_cpu(tag->t_blocknr); 345 if (JFS_HAS_INCOMPAT_FEATURE(journal, JFS_FEATURE_INCOMPAT_64BIT)) 346 block |= (u64)ext2fs_be32_to_cpu(tag->t_blocknr_high) << 32; 347 return block; 348} 349 350/* 351 * calc_chksums calculates the checksums for the blocks described in the 352 * descriptor block. 353 */ 354static int calc_chksums(journal_t *journal, struct buffer_head *bh, 355 unsigned long *next_log_block, __u32 *crc32_sum) 356{ 357 int i, num_blks, err; 358 unsigned long io_block; 359 struct buffer_head *obh; 360 361 num_blks = count_tags(journal, bh); 362 /* Calculate checksum of the descriptor block. */ 363 *crc32_sum = crc32_be(*crc32_sum, (void *)bh->b_data, bh->b_size); 364 365 for (i = 0; i < num_blks; i++) { 366 io_block = (*next_log_block)++; 367 wrap(journal, *next_log_block); 368 err = jread(&obh, journal, io_block); 369 if (err) { 370 printk(KERN_ERR "JBD2: IO error %d recovering block " 371 "%lu in log\n", err, io_block); 372 return 1; 373 } else { 374 *crc32_sum = crc32_be(*crc32_sum, (void *)obh->b_data, 375 obh->b_size); 376 } 377 put_bh(obh); 378 } 379 return 0; 380} 381 382static int jbd2_commit_block_csum_verify(journal_t *j, void *buf) 383{ 384 struct commit_header *h; 385 __u32 provided; 386 __u32 calculated; 387 388 if (!journal_has_csum_v2or3(j)) 389 return 1; 390 391 h = buf; 392 provided = h->h_chksum[0]; 393 h->h_chksum[0] = 0; 394 calculated = jbd2_chksum(j, j->j_csum_seed, buf, j->j_blocksize); 395 h->h_chksum[0] = provided; 396 397 return provided == ext2fs_cpu_to_be32(calculated); 398} 399 400static int jbd2_block_tag_csum_verify(journal_t *j, journal_block_tag_t *tag, 401 void *buf, __u32 sequence) 402{ 403 journal_block_tag3_t *tag3 = (journal_block_tag3_t *)tag; 404 __u32 csum32; 405 __u32 seq; 406 407 if (!journal_has_csum_v2or3(j)) 408 return 1; 409 410 seq = ext2fs_cpu_to_be32(sequence); 411 csum32 = jbd2_chksum(j, j->j_csum_seed, (__u8 *)&seq, sizeof(seq)); 412 csum32 = jbd2_chksum(j, csum32, buf, j->j_blocksize); 413 414 if (JFS_HAS_INCOMPAT_FEATURE(j, JFS_FEATURE_INCOMPAT_CSUM_V3)) 415 return tag3->t_checksum == ext2fs_cpu_to_be32(csum32); 416 417 return tag->t_checksum == ext2fs_cpu_to_be16(csum32); 418} 419 420static int do_one_pass(journal_t *journal, 421 struct recovery_info *info, enum passtype pass) 422{ 423 unsigned int first_commit_ID, next_commit_ID; 424 unsigned long next_log_block; 425 int err, success = 0; 426 journal_superblock_t * sb; 427 journal_header_t * tmp; 428 struct buffer_head * bh; 429 unsigned int sequence; 430 int blocktype; 431 int tag_bytes = journal_tag_bytes(journal); 432 __u32 crc32_sum = ~0; /* Transactional Checksums */ 433 int descr_csum_size = 0; 434 int block_error = 0; 435 436 /* 437 * First thing is to establish what we expect to find in the log 438 * (in terms of transaction IDs), and where (in terms of log 439 * block offsets): query the superblock. 440 */ 441 442 sb = journal->j_superblock; 443 next_commit_ID = ext2fs_be32_to_cpu(sb->s_sequence); 444 next_log_block = ext2fs_be32_to_cpu(sb->s_start); 445 446 first_commit_ID = next_commit_ID; 447 if (pass == PASS_SCAN) 448 info->start_transaction = first_commit_ID; 449 450 jbd_debug(1, "Starting recovery pass %d\n", pass); 451 452 /* 453 * Now we walk through the log, transaction by transaction, 454 * making sure that each transaction has a commit block in the 455 * expected place. Each complete transaction gets replayed back 456 * into the main filesystem. 457 */ 458 459 while (1) { 460 int flags; 461 char * tagp; 462 journal_block_tag_t * tag; 463 struct buffer_head * obh; 464 struct buffer_head * nbh; 465 466 cond_resched(); 467 468 /* If we already know where to stop the log traversal, 469 * check right now that we haven't gone past the end of 470 * the log. */ 471 472 if (pass != PASS_SCAN) 473 if (tid_geq(next_commit_ID, info->end_transaction)) 474 break; 475 476 jbd_debug(2, "Scanning for sequence ID %u at %lu/%lu\n", 477 next_commit_ID, next_log_block, journal->j_last); 478 479 /* Skip over each chunk of the transaction looking 480 * either the next descriptor block or the final commit 481 * record. */ 482 483 jbd_debug(3, "JBD2: checking block %ld\n", next_log_block); 484 err = jread(&bh, journal, next_log_block); 485 if (err) 486 goto failed; 487 488 next_log_block++; 489 wrap(journal, next_log_block); 490 491 /* What kind of buffer is it? 492 * 493 * If it is a descriptor block, check that it has the 494 * expected sequence number. Otherwise, we're all done 495 * here. */ 496 497 tmp = (journal_header_t *)bh->b_data; 498 499 if (tmp->h_magic != ext2fs_cpu_to_be32(JFS_MAGIC_NUMBER)) { 500 brelse(bh); 501 break; 502 } 503 504 blocktype = ext2fs_be32_to_cpu(tmp->h_blocktype); 505 sequence = ext2fs_be32_to_cpu(tmp->h_sequence); 506 jbd_debug(3, "Found magic %d, sequence %d\n", 507 blocktype, sequence); 508 509 if (sequence != next_commit_ID) { 510 brelse(bh); 511 break; 512 } 513 514 /* OK, we have a valid descriptor block which matches 515 * all of the sequence number checks. What are we going 516 * to do with it? That depends on the pass... */ 517 518 switch(blocktype) { 519 case JFS_DESCRIPTOR_BLOCK: 520 /* Verify checksum first */ 521 if (journal_has_csum_v2or3(journal)) 522 descr_csum_size = 523 sizeof(struct journal_block_tail); 524 if (descr_csum_size > 0 && 525 !jbd2_descr_block_csum_verify(journal, 526 bh->b_data)) { 527 err = -EIO; 528 brelse(bh); 529 goto failed; 530 } 531 532 /* If it is a valid descriptor block, replay it 533 * in pass REPLAY; if journal_checksums enabled, then 534 * calculate checksums in PASS_SCAN, otherwise, 535 * just skip over the blocks it describes. */ 536 if (pass != PASS_REPLAY) { 537 if (pass == PASS_SCAN && 538 JFS_HAS_COMPAT_FEATURE(journal, 539 JFS_FEATURE_COMPAT_CHECKSUM) && 540 !info->end_transaction) { 541 if (calc_chksums(journal, bh, 542 &next_log_block, 543 &crc32_sum)) { 544 put_bh(bh); 545 break; 546 } 547 put_bh(bh); 548 continue; 549 } 550 next_log_block += count_tags(journal, bh); 551 wrap(journal, next_log_block); 552 put_bh(bh); 553 continue; 554 } 555 556 /* A descriptor block: we can now write all of 557 * the data blocks. Yay, useful work is finally 558 * getting done here! */ 559 560 tagp = &bh->b_data[sizeof(journal_header_t)]; 561 while ((tagp - bh->b_data + tag_bytes) 562 <= journal->j_blocksize - descr_csum_size) { 563 unsigned long io_block; 564 565 tag = (journal_block_tag_t *) tagp; 566 flags = ext2fs_be16_to_cpu(tag->t_flags); 567 568 io_block = next_log_block++; 569 wrap(journal, next_log_block); 570 err = jread(&obh, journal, io_block); 571 if (err) { 572 /* Recover what we can, but 573 * report failure at the end. */ 574 success = err; 575 printk(KERN_ERR 576 "JBD2: IO error %d recovering " 577 "block %ld in log\n", 578 err, io_block); 579 } else { 580 unsigned long long blocknr; 581 582 J_ASSERT(obh != NULL); 583 blocknr = read_tag_block(journal, 584 tag); 585 586 /* If the block has been 587 * revoked, then we're all done 588 * here. */ 589 if (journal_test_revoke 590 (journal, blocknr, 591 next_commit_ID)) { 592 brelse(obh); 593 ++info->nr_revoke_hits; 594 goto skip_write; 595 } 596 597 /* Look for block corruption */ 598 if (!jbd2_block_tag_csum_verify( 599 journal, tag, obh->b_data, 600 ext2fs_be32_to_cpu(tmp->h_sequence))) { 601 brelse(obh); 602 success = -EIO; 603 printk(KERN_ERR "JBD2: Invalid " 604 "checksum recovering " 605 "block %llu in log\n", 606 blocknr); 607 block_error = 1; 608 goto skip_write; 609 } 610 611 /* Find a buffer for the new 612 * data being restored */ 613 nbh = __getblk(journal->j_fs_dev, 614 blocknr, 615 journal->j_blocksize); 616 if (nbh == NULL) { 617 printk(KERN_ERR 618 "JBD2: Out of memory " 619 "during recovery.\n"); 620 err = -ENOMEM; 621 brelse(bh); 622 brelse(obh); 623 goto failed; 624 } 625 626 lock_buffer(nbh); 627 memcpy(nbh->b_data, obh->b_data, 628 journal->j_blocksize); 629 if (flags & JFS_FLAG_ESCAPE) { 630 *((__u32 *)nbh->b_data) = 631 ext2fs_cpu_to_be32(JFS_MAGIC_NUMBER); 632 } 633 634 BUFFER_TRACE(nbh, "marking dirty"); 635 set_buffer_uptodate(nbh); 636 mark_buffer_dirty(nbh); 637 BUFFER_TRACE(nbh, "marking uptodate"); 638 ++info->nr_replays; 639 /* ll_rw_block(WRITE, 1, &nbh); */ 640 unlock_buffer(nbh); 641 brelse(obh); 642 brelse(nbh); 643 } 644 645 skip_write: 646 tagp += tag_bytes; 647 if (!(flags & JFS_FLAG_SAME_UUID)) 648 tagp += 16; 649 650 if (flags & JFS_FLAG_LAST_TAG) 651 break; 652 } 653 654 brelse(bh); 655 continue; 656 657 case JFS_COMMIT_BLOCK: 658 /* How to differentiate between interrupted commit 659 * and journal corruption ? 660 * 661 * {nth transaction} 662 * Checksum Verification Failed 663 * | 664 * ____________________ 665 * | | 666 * async_commit sync_commit 667 * | | 668 * | GO TO NEXT "Journal Corruption" 669 * | TRANSACTION 670 * | 671 * {(n+1)th transanction} 672 * | 673 * _______|______________ 674 * | | 675 * Commit block found Commit block not found 676 * | | 677 * "Journal Corruption" | 678 * _____________|_________ 679 * | | 680 * nth trans corrupt OR nth trans 681 * and (n+1)th interrupted interrupted 682 * before commit block 683 * could reach the disk. 684 * (Cannot find the difference in above 685 * mentioned conditions. Hence assume 686 * "Interrupted Commit".) 687 */ 688 689 /* Found an expected commit block: if checksums 690 * are present verify them in PASS_SCAN; else not 691 * much to do other than move on to the next sequence 692 * number. */ 693 if (pass == PASS_SCAN && 694 JFS_HAS_COMPAT_FEATURE(journal, 695 JFS_FEATURE_COMPAT_CHECKSUM)) { 696 int chksum_err, chksum_seen; 697 struct commit_header *cbh = 698 (struct commit_header *)bh->b_data; 699 unsigned found_chksum = 700 ext2fs_be32_to_cpu(cbh->h_chksum[0]); 701 702 chksum_err = chksum_seen = 0; 703 704 if (info->end_transaction) { 705 journal->j_failed_commit = 706 info->end_transaction; 707 brelse(bh); 708 break; 709 } 710 711 if (crc32_sum == found_chksum && 712 cbh->h_chksum_type == JFS_CRC32_CHKSUM && 713 cbh->h_chksum_size == 714 JFS_CRC32_CHKSUM_SIZE) 715 chksum_seen = 1; 716 else if (!(cbh->h_chksum_type == 0 && 717 cbh->h_chksum_size == 0 && 718 found_chksum == 0 && 719 !chksum_seen)) 720 /* 721 * If fs is mounted using an old kernel and then 722 * kernel with journal_chksum is used then we 723 * get a situation where the journal flag has 724 * checksum flag set but checksums are not 725 * present i.e chksum = 0, in the individual 726 * commit blocks. 727 * Hence to avoid checksum failures, in this 728 * situation, this extra check is added. 729 */ 730 chksum_err = 1; 731 732 if (chksum_err) { 733 info->end_transaction = next_commit_ID; 734 735 if (!JFS_HAS_INCOMPAT_FEATURE(journal, 736 JFS_FEATURE_INCOMPAT_ASYNC_COMMIT)){ 737 journal->j_failed_commit = 738 next_commit_ID; 739 brelse(bh); 740 break; 741 } 742 } 743 crc32_sum = ~0; 744 } 745 if (pass == PASS_SCAN && 746 !jbd2_commit_block_csum_verify(journal, 747 bh->b_data)) { 748 info->end_transaction = next_commit_ID; 749 750 if (!JFS_HAS_INCOMPAT_FEATURE(journal, 751 JFS_FEATURE_INCOMPAT_ASYNC_COMMIT)) { 752 journal->j_failed_commit = 753 next_commit_ID; 754 brelse(bh); 755 break; 756 } 757 } 758 brelse(bh); 759 next_commit_ID++; 760 continue; 761 762 case JFS_REVOKE_BLOCK: 763 /* If we aren't in the REVOKE pass, then we can 764 * just skip over this block. */ 765 if (pass != PASS_REVOKE) { 766 brelse(bh); 767 continue; 768 } 769 770 err = scan_revoke_records(journal, bh, 771 next_commit_ID, info); 772 brelse(bh); 773 if (err) 774 goto failed; 775 continue; 776 777 default: 778 jbd_debug(3, "Unrecognised magic %d, end of scan.\n", 779 blocktype); 780 brelse(bh); 781 goto done; 782 } 783 } 784 785 done: 786 /* 787 * We broke out of the log scan loop: either we came to the 788 * known end of the log or we found an unexpected block in the 789 * log. If the latter happened, then we know that the "current" 790 * transaction marks the end of the valid log. 791 */ 792 793 if (pass == PASS_SCAN) { 794 if (!info->end_transaction) 795 info->end_transaction = next_commit_ID; 796 } else { 797 /* It's really bad news if different passes end up at 798 * different places (but possible due to IO errors). */ 799 if (info->end_transaction != next_commit_ID) { 800 printk(KERN_ERR "JBD2: recovery pass %d ended at " 801 "transaction %u, expected %u\n", 802 pass, next_commit_ID, info->end_transaction); 803 if (!success) 804 success = -EIO; 805 } 806 } 807 if (block_error && success == 0) 808 success = -EIO; 809 return success; 810 811 failed: 812 return err; 813} 814 815static int jbd2_revoke_block_csum_verify(journal_t *j, 816 void *buf) 817{ 818 struct journal_revoke_tail *tail; 819 __u32 provided; 820 __u32 calculated; 821 822 if (!journal_has_csum_v2or3(j)) 823 return 1; 824 825 tail = (struct journal_revoke_tail *)(buf + j->j_blocksize - 826 sizeof(struct journal_revoke_tail)); 827 provided = tail->r_checksum; 828 tail->r_checksum = 0; 829 calculated = jbd2_chksum(j, j->j_csum_seed, buf, j->j_blocksize); 830 tail->r_checksum = provided; 831 832 return provided == ext2fs_cpu_to_be32(calculated); 833} 834 835/* Scan a revoke record, marking all blocks mentioned as revoked. */ 836 837static int scan_revoke_records(journal_t *journal, struct buffer_head *bh, 838 tid_t sequence, struct recovery_info *info) 839{ 840 journal_revoke_header_t *header; 841 int offset, max; 842 int record_len = 4; 843 844 header = (journal_revoke_header_t *) bh->b_data; 845 offset = sizeof(journal_revoke_header_t); 846 max = ext2fs_be32_to_cpu(header->r_count); 847 848 if (!jbd2_revoke_block_csum_verify(journal, header)) 849 return -EINVAL; 850 851 if (JFS_HAS_INCOMPAT_FEATURE(journal, JFS_FEATURE_INCOMPAT_64BIT)) 852 record_len = 8; 853 854 while (offset + record_len <= max) { 855 unsigned long long blocknr; 856 int err; 857 858 if (record_len == 4) 859 blocknr = ext2fs_be32_to_cpu(* ((__u32 *) (bh->b_data+offset))); 860 else 861 blocknr = ext2fs_be64_to_cpu(* ((__u64 *) (bh->b_data+offset))); 862 offset += record_len; 863 err = journal_set_revoke(journal, blocknr, sequence); 864 if (err) 865 return err; 866 ++info->nr_revokes; 867 } 868 return 0; 869} 870