lustre/kernel_patches/patches/jbd-journal-chksum-2.6-sles10.patch

   1 Index: linux-2.6.16/fs/jbd/commit.c
   2 ===================================================================
   3 --- linux-2.6.16.orig/fs/jbd/commit.c
   4 +++ linux-2.6.16/fs/jbd/commit.c
   5 @@ -22,6 +22,7 @@
   6  #include <linux/pagemap.h>
   7  #include <linux/smp_lock.h>
   8  #include <linux/jiffies.h>
   9 +#include <linux/crc32.h>
  10
  11  /*
  12   * Default IO end handler for temporary BJ_IO buffer_heads.
  13 @@ -94,19 +95,23 @@ static int inverted_lock(journal_t *jour
  14         return 1;
  15  }
  16
  17 -/* Done it all: now write the commit record.  We should have
  18 +/*
  19 + * Done it all: now submit the commit record.  We should have
  20   * cleaned up our previous buffers by now, so if we are in abort
  21   * mode we can now just skip the rest of the journal write
  22   * entirely.
  23   *
  24   * Returns 1 if the journal needs to be aborted or 0 on success
  25   */
  26 -static int journal_write_commit_record(journal_t *journal,
  27 -                                       transaction_t *commit_transaction)
  28 +static int journal_submit_commit_record(journal_t *journal,
  29 +                                       transaction_t *commit_transaction,
  30 +                                       struct buffer_head **cbh,
  31 +                                       __u32 crc32_sum)
  32  {
  33         struct journal_head *descriptor;
  34 +       struct commit_header *tmp;
  35         struct buffer_head *bh;
  36 -       int i, ret;
  37 +       int ret;
  38         int barrier_done = 0;
  39
  40         if (is_journal_aborted(journal))
  41 @@ -118,21 +123,34 @@ static int journal_write_commit_record(j
  42
  43         bh = jh2bh(descriptor);
  44
  45 -       /* AKPM: buglet - add `i' to tmp! */
  46 -       for (i = 0; i < bh->b_size; i += 512) {
  47 -               journal_header_t *tmp = (journal_header_t*)bh->b_data;
  48 -               tmp->h_magic = cpu_to_be32(JFS_MAGIC_NUMBER);
  49 -               tmp->h_blocktype = cpu_to_be32(JFS_COMMIT_BLOCK);
  50 -               tmp->h_sequence = cpu_to_be32(commit_transaction->t_tid);
  51 +       tmp = (struct commit_header *)bh->b_data;
  52 +       tmp->h_magic = cpu_to_be32(JFS_MAGIC_NUMBER);
  53 +       tmp->h_blocktype = cpu_to_be32(JFS_COMMIT_BLOCK);
  54 +       tmp->h_sequence = cpu_to_be32(commit_transaction->t_tid);
  55 +
  56 +       if (JFS_HAS_COMPAT_FEATURE(journal,
  57 +                               JFS_FEATURE_COMPAT_CHECKSUM)) {
  58 +               tmp->h_chksum_type      = JFS_CRC32_CHKSUM;
  59 +               tmp->h_chksum_size      = JFS_CRC32_CHKSUM_SIZE;
  60 +               tmp->h_chksum[0]        = cpu_to_be32(crc32_sum);
  61         }
  62
  63 -       JBUFFER_TRACE(descriptor, "write commit block");
  64 +       JBUFFER_TRACE(descriptor, "submit commit block");
  65 +       lock_buffer(bh);
  66 +
  67         set_buffer_dirty(bh);
  68 -       if (journal->j_flags & JFS_BARRIER) {
  69 +       set_buffer_uptodate(bh);
  70 +       bh->b_end_io = journal_end_buffer_io_sync;
  71 +
  72 +       if (journal->j_flags & JFS_BARRIER &&
  73 +               !JFS_HAS_INCOMPAT_FEATURE(journal,
  74 +                                        JFS_FEATURE_INCOMPAT_ASYNC_COMMIT)) {
  75 +
  76                 set_buffer_ordered(bh);
  77                 barrier_done = 1;
  78         }
  79 -       ret = sync_dirty_buffer(bh);
  80 +       ret = submit_bh(WRITE, bh);
  81 +
  82         if (barrier_done)
  83                 clear_buffer_ordered(bh);
  84         /* is it possible for another commit to fail at roughly
  85 @@ -152,14 +170,87 @@ static int journal_write_commit_record(j
  86                 spin_unlock(&journal->j_state_lock);
  87
  88                 /* And try again, without the barrier */
  89 +               lock_buffer(bh);
  90                 set_buffer_uptodate(bh);
  91                 set_buffer_dirty(bh);
  92 -               ret = sync_dirty_buffer(bh);
  93 +               ret = submit_bh(WRITE, bh);
  94         }
  95 -       put_bh(bh);             /* One for getblk() */
  96 -       journal_put_journal_head(descriptor);
  97 +       *cbh = bh;
  98 +       return ret;
  99 +}
 100
 101 -       return (ret == -EIO);
 102 +/*
 103 + * This function along with journal_submit_commit_record
 104 + * allows to write the commit record asynchronously.
 105 + */
 106 +static int journal_wait_on_commit_record(struct buffer_head *bh)
 107 +{
 108 +       int ret = 0;
 109 +
 110 +       clear_buffer_dirty(bh);
 111 +       wait_on_buffer(bh);
 112 +
 113 +       if (unlikely(!buffer_uptodate(bh)))
 114 +               ret = -EIO;
 115 +       put_bh(bh);            /* One for getblk() */
 116 +       journal_put_journal_head(bh2jh(bh));
 117 +
 118 +       return ret;
 119 +}
 120 +
 121 +/*
 122 + * Wait for all submitted IO to complete.
 123 + */
 124 +static int journal_wait_on_locked_list(journal_t *journal,
 125 +                                      transaction_t *commit_transaction)
 126 +{
 127 +       int ret = 0;
 128 +       struct journal_head *jh;
 129 +
 130 +       while (commit_transaction->t_locked_list) {
 131 +               struct buffer_head *bh;
 132 +
 133 +               jh = commit_transaction->t_locked_list->b_tprev;
 134 +               bh = jh2bh(jh);
 135 +               get_bh(bh);
 136 +               if (buffer_locked(bh)) {
 137 +                       spin_unlock(&journal->j_list_lock);
 138 +                       wait_on_buffer(bh);
 139 +                       if (unlikely(!buffer_uptodate(bh)))
 140 +                               ret = -EIO;
 141 +                       spin_lock(&journal->j_list_lock);
 142 +               }
 143 +               if (!inverted_lock(journal, bh)) {
 144 +                       put_bh(bh);
 145 +                       spin_lock(&journal->j_list_lock);
 146 +                       continue;
 147 +               }
 148 +               if (buffer_jbd(bh) && jh->b_jlist == BJ_Locked) {
 149 +                       __journal_unfile_buffer(jh);
 150 +                       jbd_unlock_bh_state(bh);
 151 +                       journal_remove_journal_head(bh);
 152 +                       put_bh(bh);
 153 +               } else {
 154 +                       jbd_unlock_bh_state(bh);
 155 +               }
 156 +               put_bh(bh);
 157 +               cond_resched_lock(&journal->j_list_lock);
 158 +       }
 159 +       return ret;
 160 +}
 161 +
 162 +static inline __u32 jbd_checksum_data(__u32 crc32_sum, struct buffer_head *bh)
 163 +{
 164 +       struct page *page = bh->b_page;
 165 +       char *addr;
 166 +       __u32 checksum;
 167 +
 168 +       addr = kmap_atomic(page, KM_USER0);
 169 +       checksum = crc32_be(crc32_sum,
 170 +                           (void *)(addr + offset_in_page(bh->b_data)),
 171 +                           bh->b_size);
 172 +       kunmap_atomic(addr, KM_USER0);
 173 +       return checksum;
 174  }
 175
 176  void journal_do_submit_data(struct buffer_head **wbuf, int bufs)
 177 @@ -296,6 +387,8 @@ void journal_commit_transaction(journal_
 178         int first_tag = 0;
 179         int tag_flag;
 180         int i;
 181 +       struct buffer_head *cbh = NULL; /* For transactional checksums */
 182 +       __u32 crc32_sum = ~0;
 183
 184         /*
 185          * First job: lock down the current transaction and wait for
 186 @@ -439,38 +532,15 @@ void journal_commit_transaction(journal_
 187         journal_submit_data_buffers(journal, commit_transaction);
 188
 189         /*
 190 -        * Wait for all previously submitted IO to complete.
 191 +        * Wait for all previously submitted IO to complete if commit
 192 +        * record is to be written synchronously.
 193          */
 194         spin_lock(&journal->j_list_lock);
 195 -       while (commit_transaction->t_locked_list) {
 196 -               struct buffer_head *bh;
 197 +       if (!JFS_HAS_INCOMPAT_FEATURE(journal,
 198 +               JFS_FEATURE_INCOMPAT_ASYNC_COMMIT))
 199 +               err = journal_wait_on_locked_list(journal,
 200 +                                                 commit_transaction);
 201
 202 -               jh = commit_transaction->t_locked_list->b_tprev;
 203 -               bh = jh2bh(jh);
 204 -               get_bh(bh);
 205 -               if (buffer_locked(bh)) {
 206 -                       spin_unlock(&journal->j_list_lock);
 207 -                       wait_on_buffer(bh);
 208 -                       if (unlikely(!buffer_uptodate(bh)))
 209 -                               err = -EIO;
 210 -                       spin_lock(&journal->j_list_lock);
 211 -               }
 212 -               if (!inverted_lock(journal, bh)) {
 213 -                       put_bh(bh);
 214 -                       spin_lock(&journal->j_list_lock);
 215 -                       continue;
 216 -               }
 217 -               if (buffer_jbd(bh) && jh->b_jlist == BJ_Locked) {
 218 -                       __journal_unfile_buffer(jh);
 219 -                       jbd_unlock_bh_state(bh);
 220 -                       journal_remove_journal_head(bh);
 221 -                       put_bh(bh);
 222 -               } else {
 223 -                       jbd_unlock_bh_state(bh);
 224 -               }
 225 -               put_bh(bh);
 226 -               cond_resched_lock(&journal->j_list_lock);
 227 -       }
 228         spin_unlock(&journal->j_list_lock);
 229
 230         if (err)
 231 @@ -643,6 +713,16 @@ void journal_commit_transaction(journal_
 232  start_journal_io:
 233                         for (i = 0; i < bufs; i++) {
 234                                 struct buffer_head *bh = wbuf[i];
 235 +                               /*
 236 +                                * Compute checksum.
 237 +                                */
 238 +                               if (JFS_HAS_COMPAT_FEATURE(journal,
 239 +                                       JFS_FEATURE_COMPAT_CHECKSUM)) {
 240 +                                       crc32_sum =
 241 +                                               jbd_checksum_data(crc32_sum,
 242 +                                                                  bh);
 243 +                               }
 244 +
 245                                 lock_buffer(bh);
 246                                 clear_buffer_dirty(bh);
 247                                 set_buffer_uptodate(bh);
 248 @@ -659,6 +739,23 @@ start_journal_io:
 249                 }
 250         }
 251
 252 +       /* Done it all: now write the commit record asynchronously. */
 253 +
 254 +       if (JFS_HAS_INCOMPAT_FEATURE(journal,
 255 +               JFS_FEATURE_INCOMPAT_ASYNC_COMMIT)) {
 256 +               err = journal_submit_commit_record(journal, commit_transaction,
 257 +                                                &cbh, crc32_sum);
 258 +               if (err)
 259 +                       __journal_abort_hard(journal);
 260 +
 261 +               spin_lock(&journal->j_list_lock);
 262 +               err = journal_wait_on_locked_list(journal,
 263 +                                               commit_transaction);
 264 +               spin_unlock(&journal->j_list_lock);
 265 +               if (err)
 266 +                       __journal_abort_hard(journal);
 267 +       }
 268 +
 269         /* Lo and behold: we have just managed to send a transaction to
 270             the log.  Before we can commit it, wait for the IO so far to
 271             complete.  Control buffers being written are on the
 272 @@ -757,9 +854,15 @@ wait_for_iobuf:
 273         }
 274
 275         jbd_debug(3, "JBD: commit phase 6\n");
 276 -
 277 -       if (journal_write_commit_record(journal, commit_transaction))
 278 -               err = -EIO;
 279 +
 280 +       if (!JFS_HAS_INCOMPAT_FEATURE(journal,
 281 +               JFS_FEATURE_INCOMPAT_ASYNC_COMMIT)) {
 282 +               err = journal_submit_commit_record(journal, commit_transaction,
 283 +                                               &cbh, crc32_sum);
 284 +               if (err)
 285 +                       __journal_abort_hard(journal);
 286 +       }
 287 +       err = journal_wait_on_commit_record(cbh);
 288
 289         if (err)
 290                 __journal_abort_hard(journal);
 291 Index: linux-2.6.16/fs/jbd/recovery.c
 292 ===================================================================
 293 --- linux-2.6.16.orig/fs/jbd/recovery.c
 294 +++ linux-2.6.16/fs/jbd/recovery.c
 295 @@ -21,6 +21,7 @@
 296  #include <linux/jbd.h>
 297  #include <linux/errno.h>
 298  #include <linux/slab.h>
 299 +#include <linux/crc32.h>
 300  #endif
 301
 302  /*
 303 @@ -307,6 +308,38 @@ int journal_skip_recovery(journal_t *jou
 304         return err;
 305  }
 306
 307 +/*
 308 + * calc_chksums calculates the checksums for the blocks described in the
 309 + * descriptor block.
 310 + */
 311 +static int calc_chksums(journal_t *journal, struct buffer_head *bh,
 312 +                      unsigned long *next_log_block, __u32 *crc32_sum)
 313 +{
 314 +       int i, num_blks, err;
 315 +       unsigned long io_block;
 316 +       struct buffer_head *obh;
 317 +
 318 +       num_blks = count_tags(bh, journal->j_blocksize);
 319 +       /* Calculate checksum of the descriptor block. */
 320 +       *crc32_sum = crc32_be(*crc32_sum, (void *)bh->b_data, bh->b_size);
 321 +
 322 +       for (i = 0; i < num_blks; i++) {
 323 +               io_block = (*next_log_block)++;
 324 +               wrap(journal, *next_log_block);
 325 +               err = jread(&obh, journal, io_block);
 326 +               if (err) {
 327 +                       printk(KERN_ERR "JBD: IO error %d recovering block "
 328 +                               "%lu in log\n", err, io_block);
 329 +                       return 1;
 330 +               } else {
 331 +                       *crc32_sum = crc32_be(*crc32_sum, (void *)obh->b_data,
 332 +                                    obh->b_size);
 333 +               }
 334 +               put_bh(obh);
 335 +       }
 336 +       return 0;
 337 +}
 338 +
 339  static int do_one_pass(journal_t *journal,
 340                         struct recovery_info *info, enum passtype pass)
 341  {
 342 @@ -318,6 +351,7 @@ static int do_one_pass(journal_t *journa
 343         struct buffer_head *    bh;
 344         unsigned int            sequence;
 345         int                     blocktype;
 346 +       __u32                   crc32_sum = ~0; /* Transactional Checksums */
 347
 348         /* Precompute the maximum metadata descriptors in a descriptor block */
 349         int                     MAX_BLOCKS_PER_DESC;
 350 @@ -409,9 +443,24 @@ static int do_one_pass(journal_t *journa
 351                 switch(blocktype) {
 352                 case JFS_DESCRIPTOR_BLOCK:
 353                         /* If it is a valid descriptor block, replay it
 354 -                        * in pass REPLAY; otherwise, just skip over the
 355 -                        * blocks it describes. */
 356 +                        * in pass REPLAY; if journal_checksums enabled, then
 357 +                        * calculate checksums in PASS_SCAN, otherwise,
 358 +                        * just skip over the blocks it describes. */
 359                         if (pass != PASS_REPLAY) {
 360 +                               if (pass == PASS_SCAN &&
 361 +                                   JFS_HAS_COMPAT_FEATURE(journal,
 362 +                                           JFS_FEATURE_COMPAT_CHECKSUM) &&
 363 +                                   !info->end_transaction) {
 364 +                                       if (calc_chksums(journal, bh,
 365 +                                                       &next_log_block,
 366 +                                                       &crc32_sum)) {
 367 +                                               put_bh(bh);
 368 +                                               break;
 369 +                                       }
 370 +                                       put_bh(bh);
 371 +                                       continue;
 372 +                               }
 373 +
 374                                 next_log_block +=
 375                                         count_tags(bh, journal->j_blocksize);
 376                                 wrap(journal, next_log_block);
 377 @@ -506,9 +555,97 @@ static int do_one_pass(journal_t *journa
 378                         continue;
 379
 380                 case JFS_COMMIT_BLOCK:
 381 -                       /* Found an expected commit block: not much to
 382 -                        * do other than move on to the next sequence
 383 +                       /*     How to differentiate between interrupted commit
 384 +                        *               and journal corruption ?
 385 +                        *
 386 +                        * {nth transaction}
 387 +                        *        Checksum Verification Failed
 388 +                        *                       |
 389 +                        *               ____________________
 390 +                        *              |                    |
 391 +                        *      async_commit             sync_commit
 392 +                        *              |                    |
 393 +                        *              | GO TO NEXT    "Journal Corruption"
 394 +                        *              | TRANSACTION
 395 +                        *              |
 396 +                        * {(n+1)th transanction}
 397 +                        *              |
 398 +                        *       _______|______________
 399 +                        *      |                     |
 400 +                        * Commit block found   Commit block not found
 401 +                        *      |                     |
 402 +                        * "Journal Corruption"       |
 403 +                        *               _____________|__________
 404 +                        *              |                       |
 405 +                        *      nth trans corrupt       OR   nth trans
 406 +                        *      and (n+1)th interrupted     interrupted
 407 +                        *      before commit block
 408 +                        *      could reach the disk.
 409 +                        *      (Cannot find the difference in above
 410 +                        *       mentioned conditions. Hence assume
 411 +                        *       "Interrupted Commit".)
 412 +                        */
 413 +
 414 +                       /* Found an expected commit block: if checksums
 415 +                        * are present verify them in PASS_SCAN; else not
 416 +                        * much to do other than move on to the next sequence
 417                          * number. */
 418 +                       if (pass == PASS_SCAN &&
 419 +                           JFS_HAS_COMPAT_FEATURE(journal,
 420 +                                   JFS_FEATURE_COMPAT_CHECKSUM)) {
 421 +                               int chksum_err, chksum_seen;
 422 +                               struct commit_header *cbh =
 423 +                                       (struct commit_header *)bh->b_data;
 424 +                               unsigned found_chksum =
 425 +                                               be32_to_cpu(cbh->h_chksum[0]);
 426 +
 427 +                               chksum_err = chksum_seen = 0;
 428 +
 429 +                               if (info->end_transaction) {
 430 +                                       printk(KERN_ERR "JBD: Transaction %u "
 431 +                                               "found to be corrupt.\n",
 432 +                                               next_commit_ID - 1);
 433 +                                       brelse(bh);
 434 +                                       break;
 435 +                               }
 436 +
 437 +                               if (crc32_sum == found_chksum &&
 438 +                                   cbh->h_chksum_type == JFS_CRC32_CHKSUM &&
 439 +                                   cbh->h_chksum_size ==
 440 +                                               JFS_CRC32_CHKSUM_SIZE) {
 441 +                                      chksum_seen = 1;
 442 +                               } else if (!(cbh->h_chksum_type == 0 &&
 443 +                                            cbh->h_chksum_size == 0 &&
 444 +                                            found_chksum == 0 &&
 445 +                                            !chksum_seen)) {
 446 +                               /*
 447 +                                * If fs is mounted using an old kernel and then
 448 +                                * kernel with journal_chksum is used then we
 449 +                                * get a situation where the journal flag has
 450 +                                * checksum flag set but checksums are not
 451 +                                * present i.e chksum = 0, in the individual
 452 +                                * commit blocks.
 453 +                                * Hence to avoid checksum failures, in this
 454 +                                * situation, this extra check is added.
 455 +                                */
 456 +                                               chksum_err = 1;
 457 +                               }
 458 +
 459 +                               if (chksum_err) {
 460 +                                       info->end_transaction = next_commit_ID;
 461 +
 462 +                                       if (!JFS_HAS_INCOMPAT_FEATURE(journal,
 463 +                                           JFS_FEATURE_INCOMPAT_ASYNC_COMMIT)){
 464 +                                               printk(KERN_ERR
 465 +                                                      "JBD: Transaction %u "
 466 +                                                      "found to be corrupt.\n",
 467 +                                                      next_commit_ID);
 468 +                                               brelse(bh);
 469 +                                               break;
 470 +                                       }
 471 +                               }
 472 +                               crc32_sum = ~0;
 473 +                       }
 474                         brelse(bh);
 475                         next_commit_ID++;
 476                         continue;
 477 @@ -543,9 +680,10 @@ static int do_one_pass(journal_t *journa
 478          * transaction marks the end of the valid log.
 479          */
 480
 481 -       if (pass == PASS_SCAN)
 482 -               info->end_transaction = next_commit_ID;
 483 -       else {
 484 +       if (pass == PASS_SCAN) {
 485 +               if (!info->end_transaction)
 486 +                       info->end_transaction = next_commit_ID;
 487 +       } else {
 488                 /* It's really bad news if different passes end up at
 489                  * different places (but possible due to IO errors). */
 490                 if (info->end_transaction != next_commit_ID) {
 491 Index: linux-2.6.16/fs/jbd/journal.c
 492 ===================================================================
 493 --- linux-2.6.16.orig/fs/jbd/journal.c
 494 +++ linux-2.6.16/fs/jbd/journal.c
 495 @@ -64,6 +64,7 @@ EXPORT_SYMBOL(journal_update_format);
 496  EXPORT_SYMBOL(journal_check_used_features);
 497  EXPORT_SYMBOL(journal_check_available_features);
 498  EXPORT_SYMBOL(journal_set_features);
 499 +EXPORT_SYMBOL(journal_clear_features);
 500  EXPORT_SYMBOL(journal_create);
 501  EXPORT_SYMBOL(journal_load);
 502  EXPORT_SYMBOL(journal_destroy);
 503 @@ -1565,6 +1566,33 @@ int journal_set_features (journal_t *jou
 504         return 1;
 505  }
 506
 507 +/**
 508 + * int journal_clear_features () - Clear a given journal feature in the superblock
 509 + * @journal: Journal to act on.
 510 + * @compat: bitmask of compatible features
 511 + * @ro: bitmask of features that force read-only mount
 512 + * @incompat: bitmask of incompatible features
 513 + *
 514 + * Clear a given journal feature as present on the
 515 + * superblock.  Returns true if the requested features could be reset.
 516 + *
 517 + */
 518 +int journal_clear_features (journal_t *journal, unsigned long compat,
 519 +                         unsigned long ro, unsigned long incompat)
 520 +{
 521 +       journal_superblock_t *sb;
 522 +
 523 +       jbd_debug(1, "Clear features 0x%lx/0x%lx/0x%lx\n",
 524 +                 compat, ro, incompat);
 525 +
 526 +       sb = journal->j_superblock;
 527 +
 528 +       sb->s_feature_compat    &= ~cpu_to_be32(compat);
 529 +       sb->s_feature_ro_compat &= ~cpu_to_be32(ro);
 530 +       sb->s_feature_incompat  &= ~cpu_to_be32(incompat);
 531 +
 532 +       return 1;
 533 +}
 534
 535  /**
 536   * int journal_update_format () - Update on-disk journal structure.
 537 Index: linux-2.6.16/fs/Kconfig
 538 ===================================================================
 539 --- linux-2.6.16.orig/fs/Kconfig
 540 +++ linux-2.6.16/fs/Kconfig
 541 @@ -140,6 +140,7 @@ config EXT3_FS_SECURITY
 542
 543  config JBD
 544         tristate
 545 +       select CRC32
 546         help
 547           This is a generic journaling layer for block devices.  It is
 548           currently used by the ext3 and OCFS2 file systems, but it could
 549 Index: linux-2.6.16/include/linux/jbd.h
 550 ===================================================================
 551 --- linux-2.6.16.orig/include/linux/jbd.h
 552 +++ linux-2.6.16/include/linux/jbd.h
 553 @@ -142,6 +142,29 @@ typedef struct journal_header_s
 554         __be32          h_sequence;
 555  } journal_header_t;
 556
 557 +/*
 558 + * Checksum types.
 559 + */
 560 +#define JFS_CRC32_CHKSUM   1
 561 +#define JFS_MD5_CHKSUM     2
 562 +#define JFS_SHA1_CHKSUM    3
 563 +
 564 +#define JFS_CRC32_CHKSUM_SIZE 4
 565 +
 566 +#define JFS_CHECKSUM_BYTES (32 / sizeof(u32))
 567 +/*
 568 + * Commit block header for storing transactional checksums:
 569 + */
 570 +struct commit_header
 571 +{
 572 +       __be32          h_magic;
 573 +       __be32          h_blocktype;
 574 +       __be32          h_sequence;
 575 +       unsigned char   h_chksum_type;
 576 +       unsigned char   h_chksum_size;
 577 +       unsigned char   h_padding[2];
 578 +       __be32          h_chksum[JFS_CHECKSUM_BYTES];
 579 +};
 580
 581  /*
 582   * The block tag: used to describe a single buffer in the journal
 583 @@ -228,12 +251,16 @@ typedef struct journal_superblock_s
 584         ((j)->j_format_version >= 2 &&                                  \
 585          ((j)->j_superblock->s_feature_incompat & cpu_to_be32((mask))))
 586
 587 -#define JFS_FEATURE_INCOMPAT_REVOKE    0x00000001
 588 +#define JFS_FEATURE_COMPAT_CHECKSUM    0x00000001
 589 +
 590 +#define JFS_FEATURE_INCOMPAT_REVOKE            0x00000001
 591 +#define JFS_FEATURE_INCOMPAT_ASYNC_COMMIT      0x00000004
 592
 593  /* Features known to this kernel version: */
 594 -#define JFS_KNOWN_COMPAT_FEATURES      0
 595 +#define JFS_KNOWN_COMPAT_FEATURES      JFS_FEATURE_COMPAT_CHECKSUM
 596  #define JFS_KNOWN_ROCOMPAT_FEATURES    0
 597 -#define JFS_KNOWN_INCOMPAT_FEATURES    JFS_FEATURE_INCOMPAT_REVOKE
 598 +#define JFS_KNOWN_INCOMPAT_FEATURES    (JFS_FEATURE_INCOMPAT_REVOKE | \
 599 +                                       JFS_FEATURE_INCOMPAT_ASYNC_COMMIT)
 600
 601  #ifdef __KERNEL__
 602
 603 @@ -1041,6 +1068,8 @@ extern int           journal_check_available_fe
 604                    (journal_t *, unsigned long, unsigned long, unsigned long);
 605  extern int        journal_set_features
 606                    (journal_t *, unsigned long, unsigned long, unsigned long);
 607 +extern int        journal_clear_features
 608 +                  (journal_t *, unsigned long, unsigned long, unsigned long);
 609  extern int        journal_create     (journal_t *);
 610  extern int        journal_load       (journal_t *journal);
 611  extern void       journal_destroy    (journal_t *);
 612 Index: linux-2.6.16/Documentation/filesystems/ext3.txt
 613 ===================================================================
 614 --- linux-2.6.16.orig/Documentation/filesystems/ext3.txt
 615 +++ linux-2.6.16/Documentation/filesystems/ext3.txt
 616 @@ -14,6 +14,16 @@ Options
 617  When mounting an ext3 filesystem, the following option are accepted:
 618  (*) == default
 619
 620 +journal_checksum       Enable checksumming of the journal transactions.
 621 +                       This will allow the recovery code in e2fsck and the
 622 +                       kernel to detect corruption in the kernel.  It is a
 623 +                       compatible change and will be ignored by older kernels.
 624 +
 625 +journal_async_commit   Commit block can be written to disk without waiting
 626 +                       for descriptor blocks. If enabled older kernels cannot
 627 +                       mount the device. This will enable 'journal_checksum'
 628 +                       internally.
 629 +
 630  journal=update         Update the ext3 file system's journal to the current
 631                         format.
 632