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_journal_has_csum_v2or3(j)) 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_journal_has_csum_v2or3(journal)) 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(journal_t *journal, 342 journal_block_tag_t *tag) 343 { 344 unsigned long long block = be32_to_cpu(tag->t_blocknr); 345 if (JBD2_HAS_INCOMPAT_FEATURE(journal, JBD2_FEATURE_INCOMPAT_64BIT)) 346 block |= (u64)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 */ 354 static 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 } 381 382 static int jbd2_commit_block_csum_verify(journal_t *j, void *buf) 383 { 384 struct commit_header *h; 385 __be32 provided; 386 __u32 calculated; 387 388 if (!jbd2_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 == cpu_to_be32(calculated); 398 } 399 400 static 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 __be32 seq; 406 407 if (!jbd2_journal_has_csum_v2or3(j)) 408 return 1; 409 410 seq = 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 (JBD2_HAS_INCOMPAT_FEATURE(j, JBD2_FEATURE_INCOMPAT_CSUM_V3)) 415 return tag3->t_checksum == cpu_to_be32(csum32); 416 else 417 return tag->t_checksum == cpu_to_be16(csum32); 418 } 419 420 static 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 = be32_to_cpu(sb->s_sequence); 444 next_log_block = 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 != cpu_to_be32(JBD2_MAGIC_NUMBER)) { 500 brelse(bh); 501 break; 502 } 503 504 blocktype = be32_to_cpu(tmp->h_blocktype); 505 sequence = 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 JBD2_DESCRIPTOR_BLOCK: 520 /* Verify checksum first */ 521 if (jbd2_journal_has_csum_v2or3(journal)) 522 descr_csum_size = 523 sizeof(struct jbd2_journal_block_tail); 524 if (descr_csum_size > 0 && 525 !jbd2_descr_block_csum_verify(journal, 526 bh->b_data)) { 527 printk(KERN_ERR "JBD2: Invalid checksum " 528 "recovering block %lu in log\n", 529 next_log_block); 530 err = -EIO; 531 brelse(bh); 532 goto failed; 533 } 534 535 /* If it is a valid descriptor block, replay it 536 * in pass REPLAY; if journal_checksums enabled, then 537 * calculate checksums in PASS_SCAN, otherwise, 538 * just skip over the blocks it describes. */ 539 if (pass != PASS_REPLAY) { 540 if (pass == PASS_SCAN && 541 JBD2_HAS_COMPAT_FEATURE(journal, 542 JBD2_FEATURE_COMPAT_CHECKSUM) && 543 !info->end_transaction) { 544 if (calc_chksums(journal, bh, 545 &next_log_block, 546 &crc32_sum)) { 547 put_bh(bh); 548 break; 549 } 550 put_bh(bh); 551 continue; 552 } 553 next_log_block += count_tags(journal, bh); 554 wrap(journal, next_log_block); 555 put_bh(bh); 556 continue; 557 } 558 559 /* A descriptor block: we can now write all of 560 * the data blocks. Yay, useful work is finally 561 * getting done here! */ 562 563 tagp = &bh->b_data[sizeof(journal_header_t)]; 564 while ((tagp - bh->b_data + tag_bytes) 565 <= journal->j_blocksize - descr_csum_size) { 566 unsigned long io_block; 567 568 tag = (journal_block_tag_t *) tagp; 569 flags = be16_to_cpu(tag->t_flags); 570 571 io_block = next_log_block++; 572 wrap(journal, next_log_block); 573 err = jread(&obh, journal, io_block); 574 if (err) { 575 /* Recover what we can, but 576 * report failure at the end. */ 577 success = err; 578 printk(KERN_ERR 579 "JBD2: IO error %d recovering " 580 "block %ld in log\n", 581 err, io_block); 582 } else { 583 unsigned long long blocknr; 584 585 J_ASSERT(obh != NULL); 586 blocknr = read_tag_block(journal, 587 tag); 588 589 /* If the block has been 590 * revoked, then we're all done 591 * here. */ 592 if (jbd2_journal_test_revoke 593 (journal, blocknr, 594 next_commit_ID)) { 595 brelse(obh); 596 ++info->nr_revoke_hits; 597 goto skip_write; 598 } 599 600 /* Look for block corruption */ 601 if (!jbd2_block_tag_csum_verify( 602 journal, tag, obh->b_data, 603 be32_to_cpu(tmp->h_sequence))) { 604 brelse(obh); 605 success = -EIO; 606 printk(KERN_ERR "JBD2: Invalid " 607 "checksum recovering " 608 "block %llu in log\n", 609 blocknr); 610 block_error = 1; 611 goto skip_write; 612 } 613 614 /* Find a buffer for the new 615 * data being restored */ 616 nbh = __getblk(journal->j_fs_dev, 617 blocknr, 618 journal->j_blocksize); 619 if (nbh == NULL) { 620 printk(KERN_ERR 621 "JBD2: Out of memory " 622 "during recovery.\n"); 623 err = -ENOMEM; 624 brelse(bh); 625 brelse(obh); 626 goto failed; 627 } 628 629 lock_buffer(nbh); 630 memcpy(nbh->b_data, obh->b_data, 631 journal->j_blocksize); 632 if (flags & JBD2_FLAG_ESCAPE) { 633 *((__be32 *)nbh->b_data) = 634 cpu_to_be32(JBD2_MAGIC_NUMBER); 635 } 636 637 BUFFER_TRACE(nbh, "marking dirty"); 638 set_buffer_uptodate(nbh); 639 mark_buffer_dirty(nbh); 640 BUFFER_TRACE(nbh, "marking uptodate"); 641 ++info->nr_replays; 642 /* ll_rw_block(WRITE, 1, &nbh); */ 643 unlock_buffer(nbh); 644 brelse(obh); 645 brelse(nbh); 646 } 647 648 skip_write: 649 tagp += tag_bytes; 650 if (!(flags & JBD2_FLAG_SAME_UUID)) 651 tagp += 16; 652 653 if (flags & JBD2_FLAG_LAST_TAG) 654 break; 655 } 656 657 brelse(bh); 658 continue; 659 660 case JBD2_COMMIT_BLOCK: 661 /* How to differentiate between interrupted commit 662 * and journal corruption ? 663 * 664 * {nth transaction} 665 * Checksum Verification Failed 666 * | 667 * ____________________ 668 * | | 669 * async_commit sync_commit 670 * | | 671 * | GO TO NEXT "Journal Corruption" 672 * | TRANSACTION 673 * | 674 * {(n+1)th transanction} 675 * | 676 * _______|______________ 677 * | | 678 * Commit block found Commit block not found 679 * | | 680 * "Journal Corruption" | 681 * _____________|_________ 682 * | | 683 * nth trans corrupt OR nth trans 684 * and (n+1)th interrupted interrupted 685 * before commit block 686 * could reach the disk. 687 * (Cannot find the difference in above 688 * mentioned conditions. Hence assume 689 * "Interrupted Commit".) 690 */ 691 692 /* Found an expected commit block: if checksums 693 * are present verify them in PASS_SCAN; else not 694 * much to do other than move on to the next sequence 695 * number. */ 696 if (pass == PASS_SCAN && 697 JBD2_HAS_COMPAT_FEATURE(journal, 698 JBD2_FEATURE_COMPAT_CHECKSUM)) { 699 int chksum_err, chksum_seen; 700 struct commit_header *cbh = 701 (struct commit_header *)bh->b_data; 702 unsigned found_chksum = 703 be32_to_cpu(cbh->h_chksum[0]); 704 705 chksum_err = chksum_seen = 0; 706 707 if (info->end_transaction) { 708 journal->j_failed_commit = 709 info->end_transaction; 710 brelse(bh); 711 break; 712 } 713 714 if (crc32_sum == found_chksum && 715 cbh->h_chksum_type == JBD2_CRC32_CHKSUM && 716 cbh->h_chksum_size == 717 JBD2_CRC32_CHKSUM_SIZE) 718 chksum_seen = 1; 719 else if (!(cbh->h_chksum_type == 0 && 720 cbh->h_chksum_size == 0 && 721 found_chksum == 0 && 722 !chksum_seen)) 723 /* 724 * If fs is mounted using an old kernel and then 725 * kernel with journal_chksum is used then we 726 * get a situation where the journal flag has 727 * checksum flag set but checksums are not 728 * present i.e chksum = 0, in the individual 729 * commit blocks. 730 * Hence to avoid checksum failures, in this 731 * situation, this extra check is added. 732 */ 733 chksum_err = 1; 734 735 if (chksum_err) { 736 info->end_transaction = next_commit_ID; 737 738 if (!JBD2_HAS_INCOMPAT_FEATURE(journal, 739 JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT)){ 740 journal->j_failed_commit = 741 next_commit_ID; 742 brelse(bh); 743 break; 744 } 745 } 746 crc32_sum = ~0; 747 } 748 if (pass == PASS_SCAN && 749 !jbd2_commit_block_csum_verify(journal, 750 bh->b_data)) { 751 info->end_transaction = next_commit_ID; 752 753 if (!JBD2_HAS_INCOMPAT_FEATURE(journal, 754 JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT)) { 755 journal->j_failed_commit = 756 next_commit_ID; 757 brelse(bh); 758 break; 759 } 760 } 761 brelse(bh); 762 next_commit_ID++; 763 continue; 764 765 case JBD2_REVOKE_BLOCK: 766 /* If we aren't in the REVOKE pass, then we can 767 * just skip over this block. */ 768 if (pass != PASS_REVOKE) { 769 brelse(bh); 770 continue; 771 } 772 773 err = scan_revoke_records(journal, bh, 774 next_commit_ID, info); 775 brelse(bh); 776 if (err) 777 goto failed; 778 continue; 779 780 default: 781 jbd_debug(3, "Unrecognised magic %d, end of scan.\n", 782 blocktype); 783 brelse(bh); 784 goto done; 785 } 786 } 787 788 done: 789 /* 790 * We broke out of the log scan loop: either we came to the 791 * known end of the log or we found an unexpected block in the 792 * log. If the latter happened, then we know that the "current" 793 * transaction marks the end of the valid log. 794 */ 795 796 if (pass == PASS_SCAN) { 797 if (!info->end_transaction) 798 info->end_transaction = next_commit_ID; 799 } else { 800 /* It's really bad news if different passes end up at 801 * different places (but possible due to IO errors). */ 802 if (info->end_transaction != next_commit_ID) { 803 printk(KERN_ERR "JBD2: recovery pass %d ended at " 804 "transaction %u, expected %u\n", 805 pass, next_commit_ID, info->end_transaction); 806 if (!success) 807 success = -EIO; 808 } 809 } 810 if (block_error && success == 0) 811 success = -EIO; 812 return success; 813 814 failed: 815 return err; 816 } 817 818 static int jbd2_revoke_block_csum_verify(journal_t *j, 819 void *buf) 820 { 821 struct jbd2_journal_revoke_tail *tail; 822 __be32 provided; 823 __u32 calculated; 824 825 if (!jbd2_journal_has_csum_v2or3(j)) 826 return 1; 827 828 tail = (struct jbd2_journal_revoke_tail *)(buf + j->j_blocksize - 829 sizeof(struct jbd2_journal_revoke_tail)); 830 provided = tail->r_checksum; 831 tail->r_checksum = 0; 832 calculated = jbd2_chksum(j, j->j_csum_seed, buf, j->j_blocksize); 833 tail->r_checksum = provided; 834 835 return provided == cpu_to_be32(calculated); 836 } 837 838 /* Scan a revoke record, marking all blocks mentioned as revoked. */ 839 840 static int scan_revoke_records(journal_t *journal, struct buffer_head *bh, 841 tid_t sequence, struct recovery_info *info) 842 { 843 jbd2_journal_revoke_header_t *header; 844 int offset, max; 845 int csum_size = 0; 846 __u32 rcount; 847 int record_len = 4; 848 849 header = (jbd2_journal_revoke_header_t *) bh->b_data; 850 offset = sizeof(jbd2_journal_revoke_header_t); 851 rcount = be32_to_cpu(header->r_count); 852 853 if (!jbd2_revoke_block_csum_verify(journal, header)) 854 return -EINVAL; 855 856 if (jbd2_journal_has_csum_v2or3(journal)) 857 csum_size = sizeof(struct jbd2_journal_revoke_tail); 858 if (rcount > journal->j_blocksize - csum_size) 859 return -EINVAL; 860 max = rcount; 861 862 if (JBD2_HAS_INCOMPAT_FEATURE(journal, JBD2_FEATURE_INCOMPAT_64BIT)) 863 record_len = 8; 864 865 while (offset + record_len <= max) { 866 unsigned long long blocknr; 867 int err; 868 869 if (record_len == 4) 870 blocknr = be32_to_cpu(* ((__be32 *) (bh->b_data+offset))); 871 else 872 blocknr = be64_to_cpu(* ((__be64 *) (bh->b_data+offset))); 873 offset += record_len; 874 err = jbd2_journal_set_revoke(journal, blocknr, sequence); 875 if (err) 876 return err; 877 ++info->nr_revokes; 878 } 879 return 0; 880 } 881