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 */ 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 = jbd2_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 -EIO; 144 } 145 146 err = jbd2_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 jbd2_journal_block_tail *tail; 181 __u32 provided, calculated; 182 183 if (!JBD2_HAS_INCOMPAT_FEATURE(j, JBD2_FEATURE_INCOMPAT_CSUM_V2)) 184 return 1; 185 186 tail = (struct jbd2_journal_block_tail *)(buf + j->j_blocksize - 187 sizeof(struct jbd2_journal_block_tail)); 188 provided = tail->t_checksum; 189 tail->t_checksum = 0; 190 calculated = jbd2_chksum(j, j->j_csum_seed, buf, j->j_blocksize); 191 tail->t_checksum = provided; 192 193 provided = be32_to_cpu(provided); 194 return provided == 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 (JBD2_HAS_INCOMPAT_FEATURE(journal, JBD2_FEATURE_INCOMPAT_CSUM_V2)) 209 size -= sizeof(struct jbd2_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 & cpu_to_be16(JBD2_FLAG_SAME_UUID))) 219 tagp += 16; 220 221 if (tag->t_flags & cpu_to_be16(JBD2_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 * jbd2_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 jbd2_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 be32_to_cpu(sb->s_sequence)); 267 journal->j_transaction_sequence = 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 jbd2_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 & JBD2_BARRIER) 293 blkdev_issue_flush(journal->j_fs_dev, GFP_KERNEL, NULL); 294 return err; 295 } 296 297 /** 298 * jbd2_journal_skip_recovery - Start journal and wipe exiting records 299 * @journal: journal to startup 300 * 301 * Locate any valid recovery information from the journal and set up the 302 * journal structures in memory to ignore it (presumably because the 303 * caller has evidence that it is out of date). 304 * This function does'nt appear to be exorted.. 305 * 306 * We perform one pass over the journal to allow us to tell the user how 307 * much recovery information is being erased, and to let us initialise 308 * the journal transaction sequence numbers to the next unused ID. 309 */ 310 int jbd2_journal_skip_recovery(journal_t *journal) 311 { 312 int err; 313 314 struct recovery_info info; 315 316 memset (&info, 0, sizeof(info)); 317 318 err = do_one_pass(journal, &info, PASS_SCAN); 319 320 if (err) { 321 printk(KERN_ERR "JBD2: error %d scanning journal\n", err); 322 ++journal->j_transaction_sequence; 323 } else { 324 #ifdef CONFIG_JBD2_DEBUG 325 int dropped = info.end_transaction - 326 be32_to_cpu(journal->j_superblock->s_sequence); 327 jbd_debug(1, 328 "JBD2: ignoring %d transaction%s from the journal.\n", 329 dropped, (dropped == 1) ? "" : "s"); 330 #endif 331 journal->j_transaction_sequence = ++info.end_transaction; 332 } 333 334 journal->j_tail = 0; 335 return err; 336 } 337 338 static inline unsigned long long read_tag_block(int tag_bytes, journal_block_tag_t *tag) 339 { 340 unsigned long long block = be32_to_cpu(tag->t_blocknr); 341 if (tag_bytes > JBD2_TAG_SIZE32) 342 block |= (u64)be32_to_cpu(tag->t_blocknr_high) << 32; 343 return block; 344 } 345 346 /* 347 * calc_chksums calculates the checksums for the blocks described in the 348 * descriptor block. 349 */ 350 static int calc_chksums(journal_t *journal, struct buffer_head *bh, 351 unsigned long *next_log_block, __u32 *crc32_sum) 352 { 353 int i, num_blks, err; 354 unsigned long io_block; 355 struct buffer_head *obh; 356 357 num_blks = count_tags(journal, bh); 358 /* Calculate checksum of the descriptor block. */ 359 *crc32_sum = crc32_be(*crc32_sum, (void *)bh->b_data, bh->b_size); 360 361 for (i = 0; i < num_blks; i++) { 362 io_block = (*next_log_block)++; 363 wrap(journal, *next_log_block); 364 err = jread(&obh, journal, io_block); 365 if (err) { 366 printk(KERN_ERR "JBD2: IO error %d recovering block " 367 "%lu in log\n", err, io_block); 368 return 1; 369 } else { 370 *crc32_sum = crc32_be(*crc32_sum, (void *)obh->b_data, 371 obh->b_size); 372 } 373 put_bh(obh); 374 } 375 return 0; 376 } 377 378 static int jbd2_commit_block_csum_verify(journal_t *j, void *buf) 379 { 380 struct commit_header *h; 381 __u32 provided, calculated; 382 383 if (!JBD2_HAS_INCOMPAT_FEATURE(j, JBD2_FEATURE_INCOMPAT_CSUM_V2)) 384 return 1; 385 386 h = buf; 387 provided = h->h_chksum[0]; 388 h->h_chksum[0] = 0; 389 calculated = jbd2_chksum(j, j->j_csum_seed, buf, j->j_blocksize); 390 h->h_chksum[0] = provided; 391 392 provided = be32_to_cpu(provided); 393 return provided == calculated; 394 } 395 396 static int jbd2_block_tag_csum_verify(journal_t *j, journal_block_tag_t *tag, 397 void *buf, __u32 sequence) 398 { 399 __u32 provided, calculated; 400 401 if (!JBD2_HAS_INCOMPAT_FEATURE(j, JBD2_FEATURE_INCOMPAT_CSUM_V2)) 402 return 1; 403 404 sequence = cpu_to_be32(sequence); 405 calculated = jbd2_chksum(j, j->j_csum_seed, (__u8 *)&sequence, 406 sizeof(sequence)); 407 calculated = jbd2_chksum(j, calculated, buf, j->j_blocksize); 408 provided = be32_to_cpu(tag->t_checksum); 409 410 return provided == cpu_to_be32(calculated); 411 } 412 413 static int do_one_pass(journal_t *journal, 414 struct recovery_info *info, enum passtype pass) 415 { 416 unsigned int first_commit_ID, next_commit_ID; 417 unsigned long next_log_block; 418 int err, success = 0; 419 journal_superblock_t * sb; 420 journal_header_t * tmp; 421 struct buffer_head * bh; 422 unsigned int sequence; 423 int blocktype; 424 int tag_bytes = journal_tag_bytes(journal); 425 __u32 crc32_sum = ~0; /* Transactional Checksums */ 426 int descr_csum_size = 0; 427 428 /* 429 * First thing is to establish what we expect to find in the log 430 * (in terms of transaction IDs), and where (in terms of log 431 * block offsets): query the superblock. 432 */ 433 434 sb = journal->j_superblock; 435 next_commit_ID = be32_to_cpu(sb->s_sequence); 436 next_log_block = be32_to_cpu(sb->s_start); 437 438 first_commit_ID = next_commit_ID; 439 if (pass == PASS_SCAN) 440 info->start_transaction = first_commit_ID; 441 442 jbd_debug(1, "Starting recovery pass %d\n", pass); 443 444 /* 445 * Now we walk through the log, transaction by transaction, 446 * making sure that each transaction has a commit block in the 447 * expected place. Each complete transaction gets replayed back 448 * into the main filesystem. 449 */ 450 451 while (1) { 452 int flags; 453 char * tagp; 454 journal_block_tag_t * tag; 455 struct buffer_head * obh; 456 struct buffer_head * nbh; 457 458 cond_resched(); 459 460 /* If we already know where to stop the log traversal, 461 * check right now that we haven't gone past the end of 462 * the log. */ 463 464 if (pass != PASS_SCAN) 465 if (tid_geq(next_commit_ID, info->end_transaction)) 466 break; 467 468 jbd_debug(2, "Scanning for sequence ID %u at %lu/%lu\n", 469 next_commit_ID, next_log_block, journal->j_last); 470 471 /* Skip over each chunk of the transaction looking 472 * either the next descriptor block or the final commit 473 * record. */ 474 475 jbd_debug(3, "JBD2: checking block %ld\n", next_log_block); 476 err = jread(&bh, journal, next_log_block); 477 if (err) 478 goto failed; 479 480 next_log_block++; 481 wrap(journal, next_log_block); 482 483 /* What kind of buffer is it? 484 * 485 * If it is a descriptor block, check that it has the 486 * expected sequence number. Otherwise, we're all done 487 * here. */ 488 489 tmp = (journal_header_t *)bh->b_data; 490 491 if (tmp->h_magic != cpu_to_be32(JBD2_MAGIC_NUMBER)) { 492 brelse(bh); 493 break; 494 } 495 496 blocktype = be32_to_cpu(tmp->h_blocktype); 497 sequence = be32_to_cpu(tmp->h_sequence); 498 jbd_debug(3, "Found magic %d, sequence %d\n", 499 blocktype, sequence); 500 501 if (sequence != next_commit_ID) { 502 brelse(bh); 503 break; 504 } 505 506 /* OK, we have a valid descriptor block which matches 507 * all of the sequence number checks. What are we going 508 * to do with it? That depends on the pass... */ 509 510 switch(blocktype) { 511 case JBD2_DESCRIPTOR_BLOCK: 512 /* Verify checksum first */ 513 if (JBD2_HAS_INCOMPAT_FEATURE(journal, 514 JBD2_FEATURE_INCOMPAT_CSUM_V2)) 515 descr_csum_size = 516 sizeof(struct jbd2_journal_block_tail); 517 if (descr_csum_size > 0 && 518 !jbd2_descr_block_csum_verify(journal, 519 bh->b_data)) { 520 err = -EIO; 521 goto failed; 522 } 523 524 /* If it is a valid descriptor block, replay it 525 * in pass REPLAY; if journal_checksums enabled, then 526 * calculate checksums in PASS_SCAN, otherwise, 527 * just skip over the blocks it describes. */ 528 if (pass != PASS_REPLAY) { 529 if (pass == PASS_SCAN && 530 JBD2_HAS_COMPAT_FEATURE(journal, 531 JBD2_FEATURE_COMPAT_CHECKSUM) && 532 !info->end_transaction) { 533 if (calc_chksums(journal, bh, 534 &next_log_block, 535 &crc32_sum)) { 536 put_bh(bh); 537 break; 538 } 539 put_bh(bh); 540 continue; 541 } 542 next_log_block += count_tags(journal, bh); 543 wrap(journal, next_log_block); 544 put_bh(bh); 545 continue; 546 } 547 548 /* A descriptor block: we can now write all of 549 * the data blocks. Yay, useful work is finally 550 * getting done here! */ 551 552 tagp = &bh->b_data[sizeof(journal_header_t)]; 553 while ((tagp - bh->b_data + tag_bytes) 554 <= journal->j_blocksize - descr_csum_size) { 555 unsigned long io_block; 556 557 tag = (journal_block_tag_t *) tagp; 558 flags = be16_to_cpu(tag->t_flags); 559 560 io_block = next_log_block++; 561 wrap(journal, next_log_block); 562 err = jread(&obh, journal, io_block); 563 if (err) { 564 /* Recover what we can, but 565 * report failure at the end. */ 566 success = err; 567 printk(KERN_ERR 568 "JBD2: IO error %d recovering " 569 "block %ld in log\n", 570 err, io_block); 571 } else { 572 unsigned long long blocknr; 573 574 J_ASSERT(obh != NULL); 575 blocknr = read_tag_block(tag_bytes, 576 tag); 577 578 /* If the block has been 579 * revoked, then we're all done 580 * here. */ 581 if (jbd2_journal_test_revoke 582 (journal, blocknr, 583 next_commit_ID)) { 584 brelse(obh); 585 ++info->nr_revoke_hits; 586 goto skip_write; 587 } 588 589 /* Look for block corruption */ 590 if (!jbd2_block_tag_csum_verify( 591 journal, tag, obh->b_data, 592 be32_to_cpu(tmp->h_sequence))) { 593 brelse(obh); 594 success = -EIO; 595 printk(KERN_ERR "JBD: Invalid " 596 "checksum recovering " 597 "block %llu in log\n", 598 blocknr); 599 continue; 600 } 601 602 /* Find a buffer for the new 603 * data being restored */ 604 nbh = __getblk(journal->j_fs_dev, 605 blocknr, 606 journal->j_blocksize); 607 if (nbh == NULL) { 608 printk(KERN_ERR 609 "JBD2: Out of memory " 610 "during recovery.\n"); 611 err = -ENOMEM; 612 brelse(bh); 613 brelse(obh); 614 goto failed; 615 } 616 617 lock_buffer(nbh); 618 memcpy(nbh->b_data, obh->b_data, 619 journal->j_blocksize); 620 if (flags & JBD2_FLAG_ESCAPE) { 621 *((__be32 *)nbh->b_data) = 622 cpu_to_be32(JBD2_MAGIC_NUMBER); 623 } 624 625 BUFFER_TRACE(nbh, "marking dirty"); 626 set_buffer_uptodate(nbh); 627 mark_buffer_dirty(nbh); 628 BUFFER_TRACE(nbh, "marking uptodate"); 629 ++info->nr_replays; 630 /* ll_rw_block(WRITE, 1, &nbh); */ 631 unlock_buffer(nbh); 632 brelse(obh); 633 brelse(nbh); 634 } 635 636 skip_write: 637 tagp += tag_bytes; 638 if (!(flags & JBD2_FLAG_SAME_UUID)) 639 tagp += 16; 640 641 if (flags & JBD2_FLAG_LAST_TAG) 642 break; 643 } 644 645 brelse(bh); 646 continue; 647 648 case JBD2_COMMIT_BLOCK: 649 /* How to differentiate between interrupted commit 650 * and journal corruption ? 651 * 652 * {nth transaction} 653 * Checksum Verification Failed 654 * | 655 * ____________________ 656 * | | 657 * async_commit sync_commit 658 * | | 659 * | GO TO NEXT "Journal Corruption" 660 * | TRANSACTION 661 * | 662 * {(n+1)th transanction} 663 * | 664 * _______|______________ 665 * | | 666 * Commit block found Commit block not found 667 * | | 668 * "Journal Corruption" | 669 * _____________|_________ 670 * | | 671 * nth trans corrupt OR nth trans 672 * and (n+1)th interrupted interrupted 673 * before commit block 674 * could reach the disk. 675 * (Cannot find the difference in above 676 * mentioned conditions. Hence assume 677 * "Interrupted Commit".) 678 */ 679 680 /* Found an expected commit block: if checksums 681 * are present verify them in PASS_SCAN; else not 682 * much to do other than move on to the next sequence 683 * number. */ 684 if (pass == PASS_SCAN && 685 JBD2_HAS_COMPAT_FEATURE(journal, 686 JBD2_FEATURE_COMPAT_CHECKSUM)) { 687 int chksum_err, chksum_seen; 688 struct commit_header *cbh = 689 (struct commit_header *)bh->b_data; 690 unsigned found_chksum = 691 be32_to_cpu(cbh->h_chksum[0]); 692 693 chksum_err = chksum_seen = 0; 694 695 if (info->end_transaction) { 696 journal->j_failed_commit = 697 info->end_transaction; 698 brelse(bh); 699 break; 700 } 701 702 if (crc32_sum == found_chksum && 703 cbh->h_chksum_type == JBD2_CRC32_CHKSUM && 704 cbh->h_chksum_size == 705 JBD2_CRC32_CHKSUM_SIZE) 706 chksum_seen = 1; 707 else if (!(cbh->h_chksum_type == 0 && 708 cbh->h_chksum_size == 0 && 709 found_chksum == 0 && 710 !chksum_seen)) 711 /* 712 * If fs is mounted using an old kernel and then 713 * kernel with journal_chksum is used then we 714 * get a situation where the journal flag has 715 * checksum flag set but checksums are not 716 * present i.e chksum = 0, in the individual 717 * commit blocks. 718 * Hence to avoid checksum failures, in this 719 * situation, this extra check is added. 720 */ 721 chksum_err = 1; 722 723 if (chksum_err) { 724 info->end_transaction = next_commit_ID; 725 726 if (!JBD2_HAS_INCOMPAT_FEATURE(journal, 727 JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT)){ 728 journal->j_failed_commit = 729 next_commit_ID; 730 brelse(bh); 731 break; 732 } 733 } 734 crc32_sum = ~0; 735 } 736 if (pass == PASS_SCAN && 737 !jbd2_commit_block_csum_verify(journal, 738 bh->b_data)) { 739 info->end_transaction = next_commit_ID; 740 741 if (!JBD2_HAS_INCOMPAT_FEATURE(journal, 742 JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT)) { 743 journal->j_failed_commit = 744 next_commit_ID; 745 brelse(bh); 746 break; 747 } 748 } 749 brelse(bh); 750 next_commit_ID++; 751 continue; 752 753 case JBD2_REVOKE_BLOCK: 754 /* If we aren't in the REVOKE pass, then we can 755 * just skip over this block. */ 756 if (pass != PASS_REVOKE) { 757 brelse(bh); 758 continue; 759 } 760 761 err = scan_revoke_records(journal, bh, 762 next_commit_ID, info); 763 brelse(bh); 764 if (err) 765 goto failed; 766 continue; 767 768 default: 769 jbd_debug(3, "Unrecognised magic %d, end of scan.\n", 770 blocktype); 771 brelse(bh); 772 goto done; 773 } 774 } 775 776 done: 777 /* 778 * We broke out of the log scan loop: either we came to the 779 * known end of the log or we found an unexpected block in the 780 * log. If the latter happened, then we know that the "current" 781 * transaction marks the end of the valid log. 782 */ 783 784 if (pass == PASS_SCAN) { 785 if (!info->end_transaction) 786 info->end_transaction = next_commit_ID; 787 } else { 788 /* It's really bad news if different passes end up at 789 * different places (but possible due to IO errors). */ 790 if (info->end_transaction != next_commit_ID) { 791 printk(KERN_ERR "JBD2: recovery pass %d ended at " 792 "transaction %u, expected %u\n", 793 pass, next_commit_ID, info->end_transaction); 794 if (!success) 795 success = -EIO; 796 } 797 } 798 799 return success; 800 801 failed: 802 return err; 803 } 804 805 static int jbd2_revoke_block_csum_verify(journal_t *j, 806 void *buf) 807 { 808 struct jbd2_journal_revoke_tail *tail; 809 __u32 provided, calculated; 810 811 if (!JBD2_HAS_INCOMPAT_FEATURE(j, JBD2_FEATURE_INCOMPAT_CSUM_V2)) 812 return 1; 813 814 tail = (struct jbd2_journal_revoke_tail *)(buf + j->j_blocksize - 815 sizeof(struct jbd2_journal_revoke_tail)); 816 provided = tail->r_checksum; 817 tail->r_checksum = 0; 818 calculated = jbd2_chksum(j, j->j_csum_seed, buf, j->j_blocksize); 819 tail->r_checksum = provided; 820 821 provided = be32_to_cpu(provided); 822 return provided == calculated; 823 } 824 825 /* Scan a revoke record, marking all blocks mentioned as revoked. */ 826 827 static int scan_revoke_records(journal_t *journal, struct buffer_head *bh, 828 tid_t sequence, struct recovery_info *info) 829 { 830 jbd2_journal_revoke_header_t *header; 831 int offset, max; 832 int record_len = 4; 833 834 header = (jbd2_journal_revoke_header_t *) bh->b_data; 835 offset = sizeof(jbd2_journal_revoke_header_t); 836 max = be32_to_cpu(header->r_count); 837 838 if (!jbd2_revoke_block_csum_verify(journal, header)) 839 return -EINVAL; 840 841 if (JBD2_HAS_INCOMPAT_FEATURE(journal, JBD2_FEATURE_INCOMPAT_64BIT)) 842 record_len = 8; 843 844 while (offset + record_len <= max) { 845 unsigned long long blocknr; 846 int err; 847 848 if (record_len == 4) 849 blocknr = be32_to_cpu(* ((__be32 *) (bh->b_data+offset))); 850 else 851 blocknr = be64_to_cpu(* ((__be64 *) (bh->b_data+offset))); 852 offset += record_len; 853 err = jbd2_journal_set_revoke(journal, blocknr, sequence); 854 if (err) 855 return err; 856 ++info->nr_revokes; 857 } 858 return 0; 859 } 860