lustre/kernel_patches/patches/jbd-journal-chksum-2.6.18-vanilla.patch

   1 Index: linux-2.6.18.8/fs/jbd/commit.c
   2 ===================================================================
   3 --- linux-2.6.18.8.orig/fs/jbd/commit.c
   4 +++ linux-2.6.18.8/fs/jbd/commit.c
   5 @@ -22,6 +22,7 @@
   6  #include <linux/mm.h>
   7  #include <linux/pagemap.h>
   8  #include <linux/smp_lock.h>
   9 +#include <linux/crc32.h>
  10
  11
  12  /*
  13 @@ -95,19 +96,23 @@ 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 @@ -119,21 +124,35 @@ 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 +       get_bh(bh);
  67 +
  68         set_buffer_dirty(bh);
  69 -       if (journal->j_flags & JFS_BARRIER) {
  70 +       set_buffer_uptodate(bh);
  71 +       bh->b_end_io = journal_end_buffer_io_sync;
  72 +
  73 +       if (journal->j_flags & JFS_BARRIER &&
  74 +               !JFS_HAS_INCOMPAT_FEATURE(journal,
  75 +                                        JFS_FEATURE_INCOMPAT_ASYNC_COMMIT)) {
  76 +
  77                 set_buffer_ordered(bh);
  78                 barrier_done = 1;
  79         }
  80 -       ret = sync_dirty_buffer(bh);
  81 +       ret = submit_bh(WRITE, bh);
  82 +
  83         /* is it possible for another commit to fail at roughly
  84          * the same time as this one?  If so, we don't want to
  85          * trust the barrier flag in the super, but instead want
  86 @@ -154,12 +173,70 @@ static int journal_write_commit_record(j
  87                 clear_buffer_ordered(bh);
  88                 set_buffer_uptodate(bh);
  89                 set_buffer_dirty(bh);
  90 -               ret = sync_dirty_buffer(bh);
  91 +               ret = submit_bh(WRITE, bh);
  92         }
  93 -       put_bh(bh);             /* One for getblk() */
  94 -       journal_put_journal_head(descriptor);
  95 +       *cbh = bh;
  96 +       return ret;
  97 +}
  98 +
  99 +/*
 100 + * This function along with journal_submit_commit_record
 101 + * allows to write the commit record asynchronously.
 102 + */
 103 +static int journal_wait_on_commit_record(struct buffer_head *bh)
 104 +{
 105 +       int ret = 0;
 106 +
 107 +       clear_buffer_dirty(bh);
 108 +       wait_on_buffer(bh);
 109 +
 110 +       if (unlikely(!buffer_uptodate(bh)))
 111 +               ret = -EIO;
 112 +       put_bh(bh);            /* One for getblk() */
 113 +       journal_put_journal_head(bh2jh(bh));
 114 +
 115 +       return ret;
 116 +}
 117 +
 118 +/*
 119 + * Wait for all submitted IO to complete.
 120 + */
 121 +static int journal_wait_on_locked_list(journal_t *journal,
 122 +                                      transaction_t *commit_transaction)
 123 +{
 124 +       int ret = 0;
 125 +       struct journal_head *jh;
 126
 127 -       return (ret == -EIO);
 128 +       while (commit_transaction->t_locked_list) {
 129 +               struct buffer_head *bh;
 130 +
 131 +               jh = commit_transaction->t_locked_list->b_tprev;
 132 +               bh = jh2bh(jh);
 133 +               get_bh(bh);
 134 +               if (buffer_locked(bh)) {
 135 +                       spin_unlock(&journal->j_list_lock);
 136 +                       wait_on_buffer(bh);
 137 +                       if (unlikely(!buffer_uptodate(bh)))
 138 +                               ret = -EIO;
 139 +                       spin_lock(&journal->j_list_lock);
 140 +               }
 141 +               if (!inverted_lock(journal, bh)) {
 142 +                       put_bh(bh);
 143 +                       spin_lock(&journal->j_list_lock);
 144 +                       continue;
 145 +               }
 146 +               if (buffer_jbd(bh) && jh->b_jlist == BJ_Locked) {
 147 +                       __journal_unfile_buffer(jh);
 148 +                       jbd_unlock_bh_state(bh);
 149 +                       journal_remove_journal_head(bh);
 150 +                       put_bh(bh);
 151 +               } else {
 152 +                       jbd_unlock_bh_state(bh);
 153 +               }
 154 +               put_bh(bh);
 155 +               cond_resched_lock(&journal->j_list_lock);
 156 +       }
 157 +       return ret;
 158  }
 159
 160  void journal_do_submit_data(struct buffer_head **wbuf, int bufs)
 161 @@ -273,6 +350,20 @@ write_out_data:
 162         journal_do_submit_data(wbuf, bufs);
 163  }
 164
 165 +static inline __u32 jbd_checksum_data(__u32 crc32_sum, struct buffer_head *bh)
 166 +{
 167 +       struct page *page = bh->b_page;
 168 +       char *addr;
 169 +       __u32 checksum;
 170 +
 171 +       addr = kmap_atomic(page, KM_USER0);
 172 +       checksum = crc32_be(crc32_sum,
 173 +                           (void *)(addr + offset_in_page(bh->b_data)),
 174 +                           bh->b_size);
 175 +       kunmap_atomic(addr, KM_USER0);
 176 +       return checksum;
 177 +}
 178 +
 179  /*
 180   * journal_commit_transaction
 181   *
 182 @@ -296,6 +387,8 @@ void journal_commit_transaction(journal_
 183         int first_tag = 0;
 184         int tag_flag;
 185         int i;
 186 +       struct buffer_head *cbh = NULL; /* For transactional checksums */
 187 +       __u32 crc32_sum = ~0;
 188
 189         /*
 190          * First job: lock down the current transaction and wait for
 191 @@ -439,39 +532,14 @@ void journal_commit_transaction(journal_
 192         journal_submit_data_buffers(journal, commit_transaction);
 193
 194         /*
 195 -        * Wait for all previously submitted IO to complete.
 196 +        * Wait for all previously submitted IO to complete if commit
 197 +        * record is to be written synchronously.
 198          */
 199         spin_lock(&journal->j_list_lock);
 200 -       while (commit_transaction->t_locked_list) {
 201 -               struct buffer_head *bh;
 202 -
 203 -               jh = commit_transaction->t_locked_list->b_tprev;
 204 -               bh = jh2bh(jh);
 205 -               get_bh(bh);
 206 -               if (buffer_locked(bh)) {
 207 -                       spin_unlock(&journal->j_list_lock);
 208 -                       wait_on_buffer(bh);
 209 -                       spin_lock(&journal->j_list_lock);
 210 -               }
 211 -               if (unlikely(!buffer_uptodate(bh)))
 212 -                       err = -EIO;
 213 -
 214 -               if (!inverted_lock(journal, bh)) {
 215 -                       put_bh(bh);
 216 -                       spin_lock(&journal->j_list_lock);
 217 -                       continue;
 218 -               }
 219 -               if (buffer_jbd(bh) && jh->b_jlist == BJ_Locked) {
 220 -                       __journal_unfile_buffer(jh);
 221 -                       jbd_unlock_bh_state(bh);
 222 -                       journal_remove_journal_head(bh);
 223 -                       put_bh(bh);
 224 -               } else {
 225 -                       jbd_unlock_bh_state(bh);
 226 -               }
 227 -               put_bh(bh);
 228 -               cond_resched_lock(&journal->j_list_lock);
 229 -       }
 230 +       if (!JFS_HAS_INCOMPAT_FEATURE(journal,
 231 +               JFS_FEATURE_INCOMPAT_ASYNC_COMMIT))
 232 +               err = journal_wait_on_locked_list(journal,
 233 +                                                 commit_transaction);
 234         spin_unlock(&journal->j_list_lock);
 235
 236         if (err)
 237 @@ -643,6 +712,16 @@ void journal_commit_transaction(journal_
 238  start_journal_io:
 239                         for (i = 0; i < bufs; i++) {
 240                                 struct buffer_head *bh = wbuf[i];
 241 +                               /*
 242 +                                * Compute checksum.
 243 +                                */
 244 +                               if (JFS_HAS_COMPAT_FEATURE(journal,
 245 +                                       JFS_FEATURE_COMPAT_CHECKSUM)) {
 246 +                                       crc32_sum =
 247 +                                               jbd_checksum_data(crc32_sum,
 248 +                                                                  bh);
 249 +                               }
 250 +
 251                                 lock_buffer(bh);
 252                                 clear_buffer_dirty(bh);
 253                                 set_buffer_uptodate(bh);
 254 @@ -659,6 +738,23 @@ start_journal_io:
 255                 }
 256         }
 257
 258 +       /* Done it all: now write the commit record asynchronously. */
 259 +
 260 +       if (JFS_HAS_INCOMPAT_FEATURE(journal,
 261 +               JFS_FEATURE_INCOMPAT_ASYNC_COMMIT)) {
 262 +               err = journal_submit_commit_record(journal, commit_transaction,
 263 +                                                &cbh, crc32_sum);
 264 +               if (err)
 265 +                       __journal_abort_hard(journal);
 266 +
 267 +               spin_lock(&journal->j_list_lock);
 268 +               err = journal_wait_on_locked_list(journal,
 269 +                                               commit_transaction);
 270 +               spin_unlock(&journal->j_list_lock);
 271 +               if (err)
 272 +                       __journal_abort_hard(journal);
 273 +       }
 274 +
 275         /* Lo and behold: we have just managed to send a transaction to
 276             the log.  Before we can commit it, wait for the IO so far to
 277             complete.  Control buffers being written are on the
 278 @@ -757,9 +853,15 @@ wait_for_iobuf:
 279         }
 280
 281         jbd_debug(3, "JBD: commit phase 6\n");
 282 -
 283 -       if (journal_write_commit_record(journal, commit_transaction))
 284 -               err = -EIO;
 285 +
 286 +       if (!JFS_HAS_INCOMPAT_FEATURE(journal,
 287 +               JFS_FEATURE_INCOMPAT_ASYNC_COMMIT)) {
 288 +               err = journal_submit_commit_record(journal, commit_transaction,
 289 +                                               &cbh, crc32_sum);
 290 +               if (err)
 291 +                       __journal_abort_hard(journal);
 292 +       }
 293 +       err = journal_wait_on_commit_record(cbh);
 294
 295         if (err)
 296                 __journal_abort_hard(journal);
 297 Index: linux-2.6.18.8/include/linux/jbd.h
 298 ===================================================================
 299 --- linux-2.6.18.8.orig/include/linux/jbd.h
 300 +++ linux-2.6.18.8/include/linux/jbd.h
 301 @@ -148,6 +148,29 @@ typedef struct journal_header_s
 302         __be32          h_sequence;
 303  } journal_header_t;
 304
 305 +/*
 306 + * Checksum types.
 307 + */
 308 +#define JFS_CRC32_CHKSUM   1
 309 +#define JFS_MD5_CHKSUM     2
 310 +#define JFS_SHA1_CHKSUM    3
 311 +
 312 +#define JFS_CRC32_CHKSUM_SIZE 4
 313 +
 314 +#define JFS_CHECKSUM_BYTES (32 / sizeof(u32))
 315 +/*
 316 + * Commit block header for storing transactional checksums:
 317 + */
 318 +struct commit_header
 319 +{
 320 +       __be32          h_magic;
 321 +       __be32          h_blocktype;
 322 +       __be32          h_sequence;
 323 +       unsigned char   h_chksum_type;
 324 +       unsigned char   h_chksum_size;
 325 +       unsigned char   h_padding[2];
 326 +       __be32          h_chksum[JFS_CHECKSUM_BYTES];
 327 +};
 328
 329  /*
 330   * The block tag: used to describe a single buffer in the journal
 331 @@ -234,12 +257,16 @@ typedef struct journal_superblock_s
 332         ((j)->j_format_version >= 2 &&                                  \
 333          ((j)->j_superblock->s_feature_incompat & cpu_to_be32((mask))))
 334
 335 -#define JFS_FEATURE_INCOMPAT_REVOKE    0x00000001
 336 +#define JFS_FEATURE_COMPAT_CHECKSUM    0x00000001
 337 +
 338 +#define JFS_FEATURE_INCOMPAT_REVOKE            0x00000001
 339 +#define JFS_FEATURE_INCOMPAT_ASYNC_COMMIT      0x00000004
 340
 341  /* Features known to this kernel version: */
 342 -#define JFS_KNOWN_COMPAT_FEATURES      0
 343 +#define JFS_KNOWN_COMPAT_FEATURES      JFS_FEATURE_COMPAT_CHECKSUM
 344  #define JFS_KNOWN_ROCOMPAT_FEATURES    0
 345 -#define JFS_KNOWN_INCOMPAT_FEATURES    JFS_FEATURE_INCOMPAT_REVOKE
 346 +#define JFS_KNOWN_INCOMPAT_FEATURES    (JFS_FEATURE_INCOMPAT_REVOKE | \
 347 +                                       JFS_FEATURE_INCOMPAT_ASYNC_COMMIT)
 348
 349  #ifdef __KERNEL__
 350
 351 @@ -1053,6 +1080,8 @@ extern int           journal_check_available_fe
 352                    (journal_t *, unsigned long, unsigned long, unsigned long);
 353  extern int        journal_set_features
 354                    (journal_t *, unsigned long, unsigned long, unsigned long);
 355 +extern int        journal_clear_features
 356 +                  (journal_t *, unsigned long, unsigned long, unsigned long);
 357  extern int        journal_create     (journal_t *);
 358  extern int        journal_load       (journal_t *journal);
 359  extern void       journal_destroy    (journal_t *);
 360 Index: linux-2.6.18.8/fs/jbd/recovery.c
 361 ===================================================================
 362 --- linux-2.6.18.8.orig/fs/jbd/recovery.c
 363 +++ linux-2.6.18.8/fs/jbd/recovery.c
 364 @@ -21,6 +21,7 @@
 365  #include <linux/jbd.h>
 366  #include <linux/errno.h>
 367  #include <linux/slab.h>
 368 +#include <linux/crc32.h>
 369  #endif
 370
 371  /*
 372 @@ -307,6 +308,38 @@ int journal_skip_recovery(journal_t *jou
 373         return err;
 374  }
 375
 376 +/*
 377 + * calc_chksums calculates the checksums for the blocks described in the
 378 + * descriptor block.
 379 + */
 380 +static int calc_chksums(journal_t *journal, struct buffer_head *bh,
 381 +                      unsigned long *next_log_block, __u32 *crc32_sum)
 382 +{
 383 +       int i, num_blks, err;
 384 +       unsigned long io_block;
 385 +       struct buffer_head *obh;
 386 +
 387 +       num_blks = count_tags(bh, journal->j_blocksize);
 388 +       /* Calculate checksum of the descriptor block. */
 389 +       *crc32_sum = crc32_be(*crc32_sum, (void *)bh->b_data, bh->b_size);
 390 +
 391 +       for (i = 0; i < num_blks; i++) {
 392 +               io_block = (*next_log_block)++;
 393 +               wrap(journal, *next_log_block);
 394 +               err = jread(&obh, journal, io_block);
 395 +               if (err) {
 396 +                       printk(KERN_ERR "JBD: IO error %d recovering block "
 397 +                               "%lu in log\n", err, io_block);
 398 +                       return 1;
 399 +               } else {
 400 +                       *crc32_sum = crc32_be(*crc32_sum, (void *)obh->b_data,
 401 +                                    obh->b_size);
 402 +               }
 403 +               put_bh(obh);
 404 +       }
 405 +       return 0;
 406 +}
 407 +
 408  static int do_one_pass(journal_t *journal,
 409                         struct recovery_info *info, enum passtype pass)
 410  {
 411 @@ -318,6 +351,7 @@ static int do_one_pass(journal_t *journa
 412         struct buffer_head *    bh;
 413         unsigned int            sequence;
 414         int                     blocktype;
 415 +       __u32                   crc32_sum = ~0; /* Transactional Checksums */
 416
 417         /* Precompute the maximum metadata descriptors in a descriptor block */
 418         int                     MAX_BLOCKS_PER_DESC;
 419 @@ -409,9 +443,24 @@ static int do_one_pass(journal_t *journa
 420                 switch(blocktype) {
 421                 case JFS_DESCRIPTOR_BLOCK:
 422                         /* If it is a valid descriptor block, replay it
 423 -                        * in pass REPLAY; otherwise, just skip over the
 424 -                        * blocks it describes. */
 425 +                        * in pass REPLAY; if journal_checksums enabled, then
 426 +                        * calculate checksums in PASS_SCAN, otherwise,
 427 +                        * just skip over the blocks it describes. */
 428                         if (pass != PASS_REPLAY) {
 429 +                               if (pass == PASS_SCAN &&
 430 +                                   JFS_HAS_COMPAT_FEATURE(journal,
 431 +                                           JFS_FEATURE_COMPAT_CHECKSUM) &&
 432 +                                   !info->end_transaction) {
 433 +                                       if (calc_chksums(journal, bh,
 434 +                                                       &next_log_block,
 435 +                                                       &crc32_sum)) {
 436 +                                               put_bh(bh);
 437 +                                               break;
 438 +                                       }
 439 +                                       put_bh(bh);
 440 +                                       continue;
 441 +                               }
 442 +
 443                                 next_log_block +=
 444                                         count_tags(bh, journal->j_blocksize);
 445                                 wrap(journal, next_log_block);
 446 @@ -506,9 +555,97 @@ static int do_one_pass(journal_t *journa
 447                         continue;
 448
 449                 case JFS_COMMIT_BLOCK:
 450 -                       /* Found an expected commit block: not much to
 451 -                        * do other than move on to the next sequence
 452 +                       /*     How to differentiate between interrupted commit
 453 +                        *               and journal corruption ?
 454 +                        *
 455 +                        * {nth transaction}
 456 +                        *        Checksum Verification Failed
 457 +                        *                       |
 458 +                        *               ____________________
 459 +                        *              |                    |
 460 +                        *      async_commit             sync_commit
 461 +                        *              |                    |
 462 +                        *              | GO TO NEXT    "Journal Corruption"
 463 +                        *              | TRANSACTION
 464 +                        *              |
 465 +                        * {(n+1)th transanction}
 466 +                        *              |
 467 +                        *       _______|______________
 468 +                        *      |                     |
 469 +                        * Commit block found   Commit block not found
 470 +                        *      |                     |
 471 +                        * "Journal Corruption"       |
 472 +                        *               _____________|__________
 473 +                        *              |                       |
 474 +                        *      nth trans corrupt       OR   nth trans
 475 +                        *      and (n+1)th interrupted     interrupted
 476 +                        *      before commit block
 477 +                        *      could reach the disk.
 478 +                        *      (Cannot find the difference in above
 479 +                        *       mentioned conditions. Hence assume
 480 +                        *       "Interrupted Commit".)
 481 +                        */
 482 +
 483 +                       /* Found an expected commit block: if checksums
 484 +                        * are present verify them in PASS_SCAN; else not
 485 +                        * much to do other than move on to the next sequence
 486                          * number. */
 487 +                       if (pass == PASS_SCAN &&
 488 +                           JFS_HAS_COMPAT_FEATURE(journal,
 489 +                                   JFS_FEATURE_COMPAT_CHECKSUM)) {
 490 +                               int chksum_err, chksum_seen;
 491 +                               struct commit_header *cbh =
 492 +                                       (struct commit_header *)bh->b_data;
 493 +                               unsigned found_chksum =
 494 +                                               be32_to_cpu(cbh->h_chksum[0]);
 495 +
 496 +                               chksum_err = chksum_seen = 0;
 497 +
 498 +                               if (info->end_transaction) {
 499 +                                       printk(KERN_ERR "JBD: Transaction %u "
 500 +                                               "found to be corrupt.\n",
 501 +                                               next_commit_ID - 1);
 502 +                                       brelse(bh);
 503 +                                       break;
 504 +                               }
 505 +
 506 +                               if (crc32_sum == found_chksum &&
 507 +                                   cbh->h_chksum_type == JFS_CRC32_CHKSUM &&
 508 +                                   cbh->h_chksum_size ==
 509 +                                               JFS_CRC32_CHKSUM_SIZE) {
 510 +                                      chksum_seen = 1;
 511 +                               } else if (!(cbh->h_chksum_type == 0 &&
 512 +                                            cbh->h_chksum_size == 0 &&
 513 +                                            found_chksum == 0 &&
 514 +                                            !chksum_seen)) {
 515 +                               /*
 516 +                                * If fs is mounted using an old kernel and then
 517 +                                * kernel with journal_chksum is used then we
 518 +                                * get a situation where the journal flag has
 519 +                                * checksum flag set but checksums are not
 520 +                                * present i.e chksum = 0, in the individual
 521 +                                * commit blocks.
 522 +                                * Hence to avoid checksum failures, in this
 523 +                                * situation, this extra check is added.
 524 +                                */
 525 +                                               chksum_err = 1;
 526 +                               }
 527 +
 528 +                               if (chksum_err) {
 529 +                                       info->end_transaction = next_commit_ID;
 530 +
 531 +                                       if (!JFS_HAS_INCOMPAT_FEATURE(journal,
 532 +                                           JFS_FEATURE_INCOMPAT_ASYNC_COMMIT)){
 533 +                                               printk(KERN_ERR
 534 +                                                      "JBD: Transaction %u "
 535 +                                                      "found to be corrupt.\n",
 536 +                                                      next_commit_ID);
 537 +                                               brelse(bh);
 538 +                                               break;
 539 +                                       }
 540 +                               }
 541 +                               crc32_sum = ~0;
 542 +                       }
 543                         brelse(bh);
 544                         next_commit_ID++;
 545                         continue;
 546 @@ -544,9 +681,10 @@ static int do_one_pass(journal_t *journa
 547          * transaction marks the end of the valid log.
 548          */
 549
 550 -       if (pass == PASS_SCAN)
 551 -               info->end_transaction = next_commit_ID;
 552 -       else {
 553 +       if (pass == PASS_SCAN) {
 554 +               if (!info->end_transaction)
 555 +                       info->end_transaction = next_commit_ID;
 556 +       } else {
 557                 /* It's really bad news if different passes end up at
 558                  * different places (but possible due to IO errors). */
 559                 if (info->end_transaction != next_commit_ID) {
 560 Index: linux-2.6.18.8/fs/jbd/journal.c
 561 ===================================================================
 562 --- linux-2.6.18.8.orig/fs/jbd/journal.c
 563 +++ linux-2.6.18.8/fs/jbd/journal.c
 564 @@ -67,6 +67,7 @@ EXPORT_SYMBOL(journal_update_format);
 565  EXPORT_SYMBOL(journal_check_used_features);
 566  EXPORT_SYMBOL(journal_check_available_features);
 567  EXPORT_SYMBOL(journal_set_features);
 568 +EXPORT_SYMBOL(journal_clear_features);
 569  EXPORT_SYMBOL(journal_create);
 570  EXPORT_SYMBOL(journal_load);
 571  EXPORT_SYMBOL(journal_destroy);
 572 @@ -1573,6 +1574,33 @@ int journal_set_features (journal_t *jou
 573         return 1;
 574  }
 575
 576 +/**
 577 + * int journal_clear_features () - Clear a given journal feature in the superblock
 578 + * @journal: Journal to act on.
 579 + * @compat: bitmask of compatible features
 580 + * @ro: bitmask of features that force read-only mount
 581 + * @incompat: bitmask of incompatible features
 582 + *
 583 + * Clear a given journal feature as present on the
 584 + * superblock.  Returns true if the requested features could be reset.
 585 + *
 586 + */
 587 +int journal_clear_features (journal_t *journal, unsigned long compat,
 588 +                         unsigned long ro, unsigned long incompat)
 589 +{
 590 +       journal_superblock_t *sb;
 591 +
 592 +       jbd_debug(1, "Clear features 0x%lx/0x%lx/0x%lx\n",
 593 +                 compat, ro, incompat);
 594 +
 595 +       sb = journal->j_superblock;
 596 +
 597 +       sb->s_feature_compat    &= ~cpu_to_be32(compat);
 598 +       sb->s_feature_ro_compat &= ~cpu_to_be32(ro);
 599 +       sb->s_feature_incompat  &= ~cpu_to_be32(incompat);
 600 +
 601 +       return 1;
 602 +}
 603
 604  /**
 605   * int journal_update_format () - Update on-disk journal structure.
 606 Index: linux-2.6.18.8/fs/Kconfig
 607 ===================================================================
 608 --- linux-2.6.18.8.orig/fs/Kconfig
 609 +++ linux-2.6.18.8/fs/Kconfig
 610 @@ -140,6 +140,7 @@ config EXT3_FS_SECURITY
 611
 612  config JBD
 613         tristate
 614 +       select CRC32
 615         help
 616           This is a generic journaling layer for block devices.  It is
 617           currently used by the ext3 and OCFS2 file systems, but it could
 618 Index: linux-2.6.18.8/Documentation/filesystems/ext3.txt
 619 ===================================================================
 620 --- linux-2.6.18.8.orig/Documentation/filesystems/ext3.txt
 621 +++ linux-2.6.18.8/Documentation/filesystems/ext3.txt
 622 @@ -14,6 +14,16 @@ Options
 623  When mounting an ext3 filesystem, the following option are accepted:
 624  (*) == default
 625
 626 +journal_checksum       Enable checksumming of the journal transactions.
 627 +                       This will allow the recovery code in e2fsck and the
 628 +                       kernel to detect corruption in the kernel.  It is a
 629 +                       compatible change and will be ignored by older kernels.
 630 +
 631 +journal_async_commit   Commit block can be written to disk without waiting
 632 +                       for descriptor blocks. If enabled older kernels cannot
 633 +                       mount the device. This will enable 'journal_checksum'
 634 +                       internally.
 635 +
 636  journal=update         Update the ext3 file system's journal to the current
 637                         format.
 638