diff options
Diffstat (limited to 'fs/jbd2/recovery.c')
| -rw-r--r-- | fs/jbd2/recovery.c | 151 |
1 files changed, 143 insertions, 8 deletions
diff --git a/fs/jbd2/recovery.c b/fs/jbd2/recovery.c index d0ce627..9216806 100644 --- a/fs/jbd2/recovery.c +++ b/fs/jbd2/recovery.c @@ -21,6 +21,7 @@ #include <linux/jbd2.h> #include <linux/errno.h> #include <linux/slab.h> +#include <linux/crc32.h> #endif /* @@ -316,6 +317,37 @@ static inline unsigned long long read_tag_block(int tag_bytes, journal_block_tag return block; } +/* + * calc_chksums calculates the checksums for the blocks described in the + * descriptor block. + */ +static int calc_chksums(journal_t *journal, struct buffer_head *bh, + unsigned long *next_log_block, __u32 *crc32_sum) +{ + int i, num_blks, err; + unsigned long io_block; + struct buffer_head *obh; + + num_blks = count_tags(journal, bh); + /* Calculate checksum of the descriptor block. */ + *crc32_sum = crc32_be(*crc32_sum, (void *)bh->b_data, bh->b_size); + + for (i = 0; i < num_blks; i++) { + io_block = (*next_log_block)++; + wrap(journal, *next_log_block); + err = jread(&obh, journal, io_block); + if (err) { + printk(KERN_ERR "JBD: IO error %d recovering block " + "%lu in log\n", err, io_block); + return 1; + } else { + *crc32_sum = crc32_be(*crc32_sum, (void *)obh->b_data, + obh->b_size); + } + } + return 0; +} + static int do_one_pass(journal_t *journal, struct recovery_info *info, enum passtype pass) { @@ -328,6 +360,7 @@ static int do_one_pass(journal_t *journal, unsigned int sequence; int blocktype; int tag_bytes = journal_tag_bytes(journal); + __u32 crc32_sum = ~0; /* Transactional Checksums */ /* Precompute the maximum metadata descriptors in a descriptor block */ int MAX_BLOCKS_PER_DESC; @@ -419,12 +452,26 @@ static int do_one_pass(journal_t *journal, switch(blocktype) { case JBD2_DESCRIPTOR_BLOCK: /* If it is a valid descriptor block, replay it - * in pass REPLAY; otherwise, just skip over the - * blocks it describes. */ + * in pass REPLAY; if journal_checksums enabled, then + * calculate checksums in PASS_SCAN, otherwise, + * just skip over the blocks it describes. */ if (pass != PASS_REPLAY) { + if (pass == PASS_SCAN && + JBD2_HAS_COMPAT_FEATURE(journal, + JBD2_FEATURE_COMPAT_CHECKSUM) && + !info->end_transaction) { + if (calc_chksums(journal, bh, + &next_log_block, + &crc32_sum)) { + put_bh(bh); + break; + } + put_bh(bh); + continue; + } next_log_block += count_tags(journal, bh); wrap(journal, next_log_block); - brelse(bh); + put_bh(bh); continue; } @@ -516,9 +563,96 @@ static int do_one_pass(journal_t *journal, continue; case JBD2_COMMIT_BLOCK: - /* Found an expected commit block: not much to - * do other than move on to the next sequence + /* How to differentiate between interrupted commit + * and journal corruption ? + * + * {nth transaction} + * Checksum Verification Failed + * | + * ____________________ + * | | + * async_commit sync_commit + * | | + * | GO TO NEXT "Journal Corruption" + * | TRANSACTION + * | + * {(n+1)th transanction} + * | + * _______|______________ + * | | + * Commit block found Commit block not found + * | | + * "Journal Corruption" | + * _____________|_________ + * | | + * nth trans corrupt OR nth trans + * and (n+1)th interrupted interrupted + * before commit block + * could reach the disk. + * (Cannot find the difference in above + * mentioned conditions. Hence assume + * "Interrupted Commit".) + */ + + /* Found an expected commit block: if checksums + * are present verify them in PASS_SCAN; else not + * much to do other than move on to the next sequence * number. */ + if (pass == PASS_SCAN && + JBD2_HAS_COMPAT_FEATURE(journal, + JBD2_FEATURE_COMPAT_CHECKSUM)) { + int chksum_err, chksum_seen; + struct commit_header *cbh = + (struct commit_header *)bh->b_data; + unsigned found_chksum = + be32_to_cpu(cbh->h_chksum[0]); + + chksum_err = chksum_seen = 0; + + if (info->end_transaction) { + printk(KERN_ERR "JBD: Transaction %u " + "found to be corrupt.\n", + next_commit_ID - 1); + brelse(bh); + break; + } + + if (crc32_sum == found_chksum && + cbh->h_chksum_type == JBD2_CRC32_CHKSUM && + cbh->h_chksum_size == + JBD2_CRC32_CHKSUM_SIZE) + chksum_seen = 1; + else if (!(cbh->h_chksum_type == 0 && + cbh->h_chksum_size == 0 && + found_chksum == 0 && + !chksum_seen)) + /* + * If fs is mounted using an old kernel and then + * kernel with journal_chksum is used then we + * get a situation where the journal flag has + * checksum flag set but checksums are not + * present i.e chksum = 0, in the individual + * commit blocks. + * Hence to avoid checksum failures, in this + * situation, this extra check is added. + */ + chksum_err = 1; + + if (chksum_err) { + info->end_transaction = next_commit_ID; + + if (!JBD2_HAS_COMPAT_FEATURE(journal, + JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT)){ + printk(KERN_ERR + "JBD: Transaction %u " + "found to be corrupt.\n", + next_commit_ID); + brelse(bh); + break; + } + } + crc32_sum = ~0; + } brelse(bh); next_commit_ID++; continue; @@ -554,9 +688,10 @@ static int do_one_pass(journal_t *journal, * transaction marks the end of the valid log. */ - if (pass == PASS_SCAN) - info->end_transaction = next_commit_ID; - else { + if (pass == PASS_SCAN) { + if (!info->end_transaction) + info->end_transaction = next_commit_ID; + } else { /* It's really bad news if different passes end up at * different places (but possible due to IO errors). */ if (info->end_transaction != next_commit_ID) { |
