void jbd2_block_tag_csum_set(journal_t *j, journal_block_tag_t *tag,
struct buffer_head *bh, __u32 sequence)
{
journal_block_tag3_t *tag3 = (journal_block_tag3_t *)tag;
__u32 csum32;
__be32 seq;
if (!journal_has_csum_v2or3(j))
return;
seq = ext2fs_cpu_to_be32(sequence);
csum32 = jbd2_chksum(j, j->j_csum_seed, (__u8 *)&seq, sizeof(seq));
csum32 = jbd2_chksum(j, csum32, bh->b_data, bh->b_size);
if (jfs_has_feature_csum3(j))
tag3->t_checksum = ext2fs_cpu_to_be32(csum32);
else
tag->t_checksum = ext2fs_cpu_to_be16(csum32);
}
static int jbd2_block_tag_csum_verify(journal_t *j, journal_block_tag_t *tag,
void *buf, __u32 sequence)
{
journal_block_tag3_t *tag3 = (journal_block_tag3_t *)tag;
__u32 csum32;
__u32 seq;
if (!journal_has_csum_v2or3(j))
return 1;
seq = ext2fs_cpu_to_be32(sequence);
csum32 = jbd2_chksum(j, j->j_csum_seed, (__u8 *)&seq, sizeof(seq));
csum32 = jbd2_chksum(j, csum32, buf, j->j_blocksize);
if (jfs_has_feature_csum3(j))
return tag3->t_checksum == ext2fs_cpu_to_be32(csum32);
return tag->t_checksum == ext2fs_cpu_to_be16(csum32);
}
static errcode_t ext2fs_journal_load(journal_t *journal)
{
ext2_filsys fs = journal->j_dev->k_fs;
journal_superblock_t *jsb;
struct buffer_head *jbh = journal->j_sb_buffer;
ll_rw_block(READ, 1, &jbh);
if (jbh->b_err)
return jbh->b_err;
jsb = journal->j_superblock;
/* If we don't even have JFS_MAGIC, we probably have a wrong inode */
if (jsb->s_header.h_magic != htonl(JFS_MAGIC_NUMBER))
return ext2fs_journal_fix_bad_inode(fs);
switch (ntohl(jsb->s_header.h_blocktype)) {
case JFS_SUPERBLOCK_V1:
journal->j_format_version = 1;
if (jsb->s_feature_compat ||
jsb->s_feature_incompat ||
jsb->s_feature_ro_compat ||
jsb->s_nr_users)
clear_v2_journal_fields(journal);
break;
case JFS_SUPERBLOCK_V2:
journal->j_format_version = 2;
if (ntohl(jsb->s_nr_users) > 1 &&
uuid_is_null(fs->super->s_journal_uuid))
clear_v2_journal_fields(journal);
if (ntohl(jsb->s_nr_users) > 1)
return EXT2_ET_JOURNAL_UNSUPP_VERSION;
break;
/*
* These should never appear in a journal super block, so if
* they do, the journal is badly corrupted.
*/
case JFS_DESCRIPTOR_BLOCK:
case JFS_COMMIT_BLOCK:
case JFS_REVOKE_BLOCK:
return EXT2_ET_CORRUPT_JOURNAL_SB;
/* If we don't understand the superblock major type, but there
* is a magic number, then it is likely to be a new format we
* just don't understand, so leave it alone. */
default:
return EXT2_ET_JOURNAL_UNSUPP_VERSION;
}
if (JFS_HAS_INCOMPAT_FEATURE(journal, ~JFS_KNOWN_INCOMPAT_FEATURES))
return EXT2_ET_UNSUPP_FEATURE;
if (JFS_HAS_RO_COMPAT_FEATURE(journal, ~JFS_KNOWN_ROCOMPAT_FEATURES))
return EXT2_ET_RO_UNSUPP_FEATURE;
/* Checksum v1-3 are mutually exclusive features. */
if (jfs_has_feature_csum2(journal) && jfs_has_feature_csum3(journal))
return EXT2_ET_CORRUPT_JOURNAL_SB;
if (journal_has_csum_v2or3(journal) &&
jfs_has_feature_checksum(journal))
return EXT2_ET_CORRUPT_JOURNAL_SB;
if (!ext2fs_journal_verify_csum_type(journal, jsb) ||
!ext2fs_journal_sb_csum_verify(journal, jsb))
return EXT2_ET_CORRUPT_JOURNAL_SB;
if (journal_has_csum_v2or3(journal))
journal->j_csum_seed = jbd2_chksum(journal, ~0, jsb->s_uuid,
sizeof(jsb->s_uuid));
/* We have now checked whether we know enough about the journal
* format to be able to proceed safely, so any other checks that
* fail we should attempt to recover from. */
if (jsb->s_blocksize != htonl(journal->j_blocksize))
return EXT2_ET_CORRUPT_JOURNAL_SB;
if (ntohl(jsb->s_maxlen) < journal->j_maxlen)
journal->j_maxlen = ntohl(jsb->s_maxlen);
else if (ntohl(jsb->s_maxlen) > journal->j_maxlen)
return EXT2_ET_CORRUPT_JOURNAL_SB;
journal->j_tail_sequence = ntohl(jsb->s_sequence);
journal->j_transaction_sequence = journal->j_tail_sequence;
journal->j_tail = ntohl(jsb->s_start);
journal->j_first = ntohl(jsb->s_first);
journal->j_last = ntohl(jsb->s_maxlen);
return 0;
}
