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 __be32 provided; 182 __u32 calculated; 183 184 if (!JBD2_HAS_INCOMPAT_FEATURE(j, JBD2_FEATURE_INCOMPAT_CSUM_V2)) 185 return 1; 186 187 tail = (struct jbd2_journal_block_tail *)(buf + j->j_blocksize - 188 sizeof(struct jbd2_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 == 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 (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 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 * jbd2_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 jbd2_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_JBD2_DEBUG 328 int dropped = info.end_transaction - 329 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 unsigned long long read_tag_block(int tag_bytes, journal_block_tag_t *tag) 342 { 343 unsigned long long block = be32_to_cpu(tag->t_blocknr); 344 if (tag_bytes > JBD2_TAG_SIZE32) 345 block |= (u64)be32_to_cpu(tag->t_blocknr_high) << 32; 346 return block; 347 } 348 349 /* 350 * calc_chksums calculates the checksums for the blocks described in the 351 * descriptor block. 352 */ 353 static int calc_chksums(journal_t *journal, struct buffer_head *bh, 354 unsigned long *next_log_block, __u32 *crc32_sum) 355 { 356 int i, num_blks, err; 357 unsigned long io_block; 358 struct buffer_head *obh; 359 360 num_blks = count_tags(journal, bh); 361 /* Calculate checksum of the descriptor block. */ 362 *crc32_sum = crc32_be(*crc32_sum, (void *)bh->b_data, bh->b_size); 363 364 for (i = 0; i < num_blks; i++) { 365 io_block = (*next_log_block)++; 366 wrap(journal, *next_log_block); 367 err = jread(&obh, journal, io_block); 368 if (err) { 369 printk(KERN_ERR "JBD2: IO error %d recovering block " 370 "%lu in log\n", err, io_block); 371 return 1; 372 } else { 373 *crc32_sum = crc32_be(*crc32_sum, (void *)obh->b_data, 374 obh->b_size); 375 } 376 put_bh(obh); 377 } 378 return 0; 379 } 380 381 static int jbd2_commit_block_csum_verify(journal_t *j, void *buf) 382 { 383 struct commit_header *h; 384 __be32 provided; 385 __u32 calculated; 386 387 if (!JBD2_HAS_INCOMPAT_FEATURE(j, JBD2_FEATURE_INCOMPAT_CSUM_V2)) 388 return 1; 389 390 h = buf; 391 provided = h->h_chksum[0]; 392 h->h_chksum[0] = 0; 393 calculated = jbd2_chksum(j, j->j_csum_seed, buf, j->j_blocksize); 394 h->h_chksum[0] = provided; 395 396 return provided == cpu_to_be32(calculated); 397 } 398 399 static int jbd2_block_tag_csum_verify(journal_t *j, journal_block_tag_t *tag, 400 void *buf, __u32 sequence) 401 { 402 __u32 csum32; 403 __be32 seq; 404 405 if (!JBD2_HAS_INCOMPAT_FEATURE(j, JBD2_FEATURE_INCOMPAT_CSUM_V2)) 406 return 1; 407 408 seq = cpu_to_be32(sequence); 409 csum32 = jbd2_chksum(j, j->j_csum_seed, (__u8 *)&seq, sizeof(seq)); 410 csum32 = jbd2_chksum(j, csum32, buf, j->j_blocksize); 411 412 return tag->t_checksum == cpu_to_be16(csum32); 413 } 414 415 static int do_one_pass(journal_t *journal, 416 struct recovery_info *info, enum passtype pass) 417 { 418 unsigned int first_commit_ID, next_commit_ID; 419 unsigned long next_log_block; 420 int err, success = 0; 421 journal_superblock_t * sb; 422 journal_header_t * tmp; 423 struct buffer_head * bh; 424 unsigned int sequence; 425 int blocktype; 426 int tag_bytes = journal_tag_bytes(journal); 427 __u32 crc32_sum = ~0; /* Transactional Checksums */ 428 int descr_csum_size = 0; 429 430 /* 431 * First thing is to establish what we expect to find in the log 432 * (in terms of transaction IDs), and where (in terms of log 433 * block offsets): query the superblock. 434 */ 435 436 sb = journal->j_superblock; 437 next_commit_ID = be32_to_cpu(sb->s_sequence); 438 next_log_block = be32_to_cpu(sb->s_start); 439 440 first_commit_ID = next_commit_ID; 441 if (pass == PASS_SCAN) 442 info->start_transaction = first_commit_ID; 443 444 jbd_debug(1, "Starting recovery pass %d\n", pass); 445 446 /* 447 * Now we walk through the log, transaction by transaction, 448 * making sure that each transaction has a commit block in the 449 * expected place. Each complete transaction gets replayed back 450 * into the main filesystem. 451 */ 452 453 while (1) { 454 int flags; 455 char * tagp; 456 journal_block_tag_t * tag; 457 struct buffer_head * obh; 458 struct buffer_head * nbh; 459 460 cond_resched(); 461 462 /* If we already know where to stop the log traversal, 463 * check right now that we haven't gone past the end of 464 * the log. */ 465 466 if (pass != PASS_SCAN) 467 if (tid_geq(next_commit_ID, info->end_transaction)) 468 break; 469 470 jbd_debug(2, "Scanning for sequence ID %u at %lu/%lu\n", 471 next_commit_ID, next_log_block, journal->j_last); 472 473 /* Skip over each chunk of the transaction looking 474 * either the next descriptor block or the final commit 475 * record. */ 476 477 jbd_debug(3, "JBD2: checking block %ld\n", next_log_block); 478 err = jread(&bh, journal, next_log_block); 479 if (err) 480 goto failed; 481 482 next_log_block++; 483 wrap(journal, next_log_block); 484 485 /* What kind of buffer is it? 486 * 487 * If it is a descriptor block, check that it has the 488 * expected sequence number. Otherwise, we're all done 489 * here. */ 490 491 tmp = (journal_header_t *)bh->b_data; 492 493 if (tmp->h_magic != cpu_to_be32(JBD2_MAGIC_NUMBER)) { 494 brelse(bh); 495 break; 496 } 497 498 blocktype = be32_to_cpu(tmp->h_blocktype); 499 sequence = be32_to_cpu(tmp->h_sequence); 500 jbd_debug(3, "Found magic %d, sequence %d\n", 501 blocktype, sequence); 502 503 if (sequence != next_commit_ID) { 504 brelse(bh); 505 break; 506 } 507 508 /* OK, we have a valid descriptor block which matches 509 * all of the sequence number checks. What are we going 510 * to do with it? That depends on the pass... */ 511 512 switch(blocktype) { 513 case JBD2_DESCRIPTOR_BLOCK: 514 /* Verify checksum first */ 515 if (JBD2_HAS_INCOMPAT_FEATURE(journal, 516 JBD2_FEATURE_INCOMPAT_CSUM_V2)) 517 descr_csum_size = 518 sizeof(struct jbd2_journal_block_tail); 519 if (descr_csum_size > 0 && 520 !jbd2_descr_block_csum_verify(journal, 521 bh->b_data)) { 522 err = -EIO; 523 goto failed; 524 } 525 526 /* If it is a valid descriptor block, replay it 527 * in pass REPLAY; if journal_checksums enabled, then 528 * calculate checksums in PASS_SCAN, otherwise, 529 * just skip over the blocks it describes. */ 530 if (pass != PASS_REPLAY) { 531 if (pass == PASS_SCAN && 532 JBD2_HAS_COMPAT_FEATURE(journal, 533 JBD2_FEATURE_COMPAT_CHECKSUM) && 534 !info->end_transaction) { 535 if (calc_chksums(journal, bh, 536 &next_log_block, 537 &crc32_sum)) { 538 put_bh(bh); 539 break; 540 } 541 put_bh(bh); 542 continue; 543 } 544 next_log_block += count_tags(journal, bh); 545 wrap(journal, next_log_block); 546 put_bh(bh); 547 continue; 548 } 549 550 /* A descriptor block: we can now write all of 551 * the data blocks. Yay, useful work is finally 552 * getting done here! */ 553 554 tagp = &bh->b_data[sizeof(journal_header_t)]; 555 while ((tagp - bh->b_data + tag_bytes) 556 <= journal->j_blocksize - descr_csum_size) { 557 unsigned long io_block; 558 559 tag = (journal_block_tag_t *) tagp; 560 flags = be16_to_cpu(tag->t_flags); 561 562 io_block = next_log_block++; 563 wrap(journal, next_log_block); 564 err = jread(&obh, journal, io_block); 565 if (err) { 566 /* Recover what we can, but 567 * report failure at the end. */ 568 success = err; 569 printk(KERN_ERR 570 "JBD2: IO error %d recovering " 571 "block %ld in log\n", 572 err, io_block); 573 } else { 574 unsigned long long blocknr; 575 576 J_ASSERT(obh != NULL); 577 blocknr = read_tag_block(tag_bytes, 578 tag); 579 580 /* If the block has been 581 * revoked, then we're all done 582 * here. */ 583 if (jbd2_journal_test_revoke 584 (journal, blocknr, 585 next_commit_ID)) { 586 brelse(obh); 587 ++info->nr_revoke_hits; 588 goto skip_write; 589 } 590 591 /* Look for block corruption */ 592 if (!jbd2_block_tag_csum_verify( 593 journal, tag, obh->b_data, 594 be32_to_cpu(tmp->h_sequence))) { 595 brelse(obh); 596 success = -EIO; 597 printk(KERN_ERR "JBD2: Invalid " 598 "checksum recovering " 599 "block %llu in log\n", 600 blocknr); 601 continue; 602 } 603 604 /* Find a buffer for the new 605 * data being restored */ 606 nbh = __getblk(journal->j_fs_dev, 607 blocknr, 608 journal->j_blocksize); 609 if (nbh == NULL) { 610 printk(KERN_ERR 611 "JBD2: Out of memory " 612 "during recovery.\n"); 613 err = -ENOMEM; 614 brelse(bh); 615 brelse(obh); 616 goto failed; 617 } 618 619 lock_buffer(nbh); 620 memcpy(nbh->b_data, obh->b_data, 621 journal->j_blocksize); 622 if (flags & JBD2_FLAG_ESCAPE) { 623 *((__be32 *)nbh->b_data) = 624 cpu_to_be32(JBD2_MAGIC_NUMBER); 625 } 626 627 BUFFER_TRACE(nbh, "marking dirty"); 628 set_buffer_uptodate(nbh); 629 mark_buffer_dirty(nbh); 630 BUFFER_TRACE(nbh, "marking uptodate"); 631 ++info->nr_replays; 632 /* ll_rw_block(WRITE, 1, &nbh); */ 633 unlock_buffer(nbh); 634 brelse(obh); 635 brelse(nbh); 636 } 637 638 skip_write: 639 tagp += tag_bytes; 640 if (!(flags & JBD2_FLAG_SAME_UUID)) 641 tagp += 16; 642 643 if (flags & JBD2_FLAG_LAST_TAG) 644 break; 645 } 646 647 brelse(bh); 648 continue; 649 650 case JBD2_COMMIT_BLOCK: 651 /* How to differentiate between interrupted commit 652 * and journal corruption ? 653 * 654 * {nth transaction} 655 * Checksum Verification Failed 656 * | 657 * ____________________ 658 * | | 659 * async_commit sync_commit 660 * | | 661 * | GO TO NEXT "Journal Corruption" 662 * | TRANSACTION 663 * | 664 * {(n+1)th transanction} 665 * | 666 * _______|______________ 667 * | | 668 * Commit block found Commit block not found 669 * | | 670 * "Journal Corruption" | 671 * _____________|_________ 672 * | | 673 * nth trans corrupt OR nth trans 674 * and (n+1)th interrupted interrupted 675 * before commit block 676 * could reach the disk. 677 * (Cannot find the difference in above 678 * mentioned conditions. Hence assume 679 * "Interrupted Commit".) 680 */ 681 682 /* Found an expected commit block: if checksums 683 * are present verify them in PASS_SCAN; else not 684 * much to do other than move on to the next sequence 685 * number. */ 686 if (pass == PASS_SCAN && 687 JBD2_HAS_COMPAT_FEATURE(journal, 688 JBD2_FEATURE_COMPAT_CHECKSUM)) { 689 int chksum_err, chksum_seen; 690 struct commit_header *cbh = 691 (struct commit_header *)bh->b_data; 692 unsigned found_chksum = 693 be32_to_cpu(cbh->h_chksum[0]); 694 695 chksum_err = chksum_seen = 0; 696 697 if (info->end_transaction) { 698 journal->j_failed_commit = 699 info->end_transaction; 700 brelse(bh); 701 break; 702 } 703 704 if (crc32_sum == found_chksum && 705 cbh->h_chksum_type == JBD2_CRC32_CHKSUM && 706 cbh->h_chksum_size == 707 JBD2_CRC32_CHKSUM_SIZE) 708 chksum_seen = 1; 709 else if (!(cbh->h_chksum_type == 0 && 710 cbh->h_chksum_size == 0 && 711 found_chksum == 0 && 712 !chksum_seen)) 713 /* 714 * If fs is mounted using an old kernel and then 715 * kernel with journal_chksum is used then we 716 * get a situation where the journal flag has 717 * checksum flag set but checksums are not 718 * present i.e chksum = 0, in the individual 719 * commit blocks. 720 * Hence to avoid checksum failures, in this 721 * situation, this extra check is added. 722 */ 723 chksum_err = 1; 724 725 if (chksum_err) { 726 info->end_transaction = next_commit_ID; 727 728 if (!JBD2_HAS_INCOMPAT_FEATURE(journal, 729 JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT)){ 730 journal->j_failed_commit = 731 next_commit_ID; 732 brelse(bh); 733 break; 734 } 735 } 736 crc32_sum = ~0; 737 } 738 if (pass == PASS_SCAN && 739 !jbd2_commit_block_csum_verify(journal, 740 bh->b_data)) { 741 info->end_transaction = next_commit_ID; 742 743 if (!JBD2_HAS_INCOMPAT_FEATURE(journal, 744 JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT)) { 745 journal->j_failed_commit = 746 next_commit_ID; 747 brelse(bh); 748 break; 749 } 750 } 751 brelse(bh); 752 next_commit_ID++; 753 continue; 754 755 case JBD2_REVOKE_BLOCK: 756 /* If we aren't in the REVOKE pass, then we can 757 * just skip over this block. */ 758 if (pass != PASS_REVOKE) { 759 brelse(bh); 760 continue; 761 } 762 763 err = scan_revoke_records(journal, bh, 764 next_commit_ID, info); 765 brelse(bh); 766 if (err) 767 goto failed; 768 continue; 769 770 default: 771 jbd_debug(3, "Unrecognised magic %d, end of scan.\n", 772 blocktype); 773 brelse(bh); 774 goto done; 775 } 776 } 777 778 done: 779 /* 780 * We broke out of the log scan loop: either we came to the 781 * known end of the log or we found an unexpected block in the 782 * log. If the latter happened, then we know that the "current" 783 * transaction marks the end of the valid log. 784 */ 785 786 if (pass == PASS_SCAN) { 787 if (!info->end_transaction) 788 info->end_transaction = next_commit_ID; 789 } else { 790 /* It's really bad news if different passes end up at 791 * different places (but possible due to IO errors). */ 792 if (info->end_transaction != next_commit_ID) { 793 printk(KERN_ERR "JBD2: recovery pass %d ended at " 794 "transaction %u, expected %u\n", 795 pass, next_commit_ID, info->end_transaction); 796 if (!success) 797 success = -EIO; 798 } 799 } 800 801 return success; 802 803 failed: 804 return err; 805 } 806 807 static int jbd2_revoke_block_csum_verify(journal_t *j, 808 void *buf) 809 { 810 struct jbd2_journal_revoke_tail *tail; 811 __be32 provided; 812 __u32 calculated; 813 814 if (!JBD2_HAS_INCOMPAT_FEATURE(j, JBD2_FEATURE_INCOMPAT_CSUM_V2)) 815 return 1; 816 817 tail = (struct jbd2_journal_revoke_tail *)(buf + j->j_blocksize - 818 sizeof(struct jbd2_journal_revoke_tail)); 819 provided = tail->r_checksum; 820 tail->r_checksum = 0; 821 calculated = jbd2_chksum(j, j->j_csum_seed, buf, j->j_blocksize); 822 tail->r_checksum = provided; 823 824 return provided == cpu_to_be32(calculated); 825 } 826 827 /* Scan a revoke record, marking all blocks mentioned as revoked. */ 828 829 static int scan_revoke_records(journal_t *journal, struct buffer_head *bh, 830 tid_t sequence, struct recovery_info *info) 831 { 832 jbd2_journal_revoke_header_t *header; 833 int offset, max; 834 int record_len = 4; 835 836 header = (jbd2_journal_revoke_header_t *) bh->b_data; 837 offset = sizeof(jbd2_journal_revoke_header_t); 838 max = be32_to_cpu(header->r_count); 839 840 if (!jbd2_revoke_block_csum_verify(journal, header)) 841 return -EINVAL; 842 843 if (JBD2_HAS_INCOMPAT_FEATURE(journal, JBD2_FEATURE_INCOMPAT_64BIT)) 844 record_len = 8; 845 846 while (offset + record_len <= max) { 847 unsigned long long blocknr; 848 int err; 849 850 if (record_len == 4) 851 blocknr = be32_to_cpu(* ((__be32 *) (bh->b_data+offset))); 852 else 853 blocknr = be64_to_cpu(* ((__be64 *) (bh->b_data+offset))); 854 offset += record_len; 855 err = jbd2_journal_set_revoke(journal, blocknr, sequence); 856 if (err) 857 return err; 858 ++info->nr_revokes; 859 } 860 return 0; 861 } 862