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jbd2: checksum descriptor blocks

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Calculate and verify a checksum of each descriptor block.

Signed-off-by: Darrick J. Wong <djwong@us.ibm.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
This commit is contained in:
Darrick J. Wong 2012-05-27 08:10:22 -04:00 committed by Theodore Ts'o
parent 42a7106de6
commit 3caa487f53
2 changed files with 60 additions and 2 deletions
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25
fs/jbd2/commit.c
View File

@ -301,6 +301,24 @@ static void write_tag_block(int tag_bytes, journal_block_tag_t *tag,
tag->t_blocknr_high = cpu_to_be32((block >> 31) >> 1);
}
static void jbd2_descr_block_csum_set(journal_t *j,
struct journal_head *descriptor)
{
struct jbd2_journal_block_tail *tail;
__u32 csum;
if (!JBD2_HAS_INCOMPAT_FEATURE(j, JBD2_FEATURE_INCOMPAT_CSUM_V2))
return;
tail = (struct jbd2_journal_block_tail *)
(jh2bh(descriptor)->b_data + j->j_blocksize -
sizeof(struct jbd2_journal_block_tail));
tail->t_checksum = 0;
csum = jbd2_chksum(j, j->j_csum_seed, jh2bh(descriptor)->b_data,
j->j_blocksize);
tail->t_checksum = cpu_to_be32(csum);
}
/*
* jbd2_journal_commit_transaction
*
@ -334,6 +352,10 @@ void jbd2_journal_commit_transaction(journal_t *journal)
unsigned long first_block;
tid_t first_tid;
int update_tail;
int csum_size = 0;
if (JBD2_HAS_INCOMPAT_FEATURE(journal, JBD2_FEATURE_INCOMPAT_CSUM_V2))
csum_size = sizeof(struct jbd2_journal_block_tail);
/*
* First job: lock down the current transaction and wait for
@ -643,7 +665,7 @@ void jbd2_journal_commit_transaction(journal_t *journal)
if (bufs == journal->j_wbufsize ||
commit_transaction->t_buffers == NULL ||
space_left < tag_bytes + 16) {
space_left < tag_bytes + 16 + csum_size) {
jbd_debug(4, "JBD2: Submit %d IOs\n", bufs);
@ -653,6 +675,7 @@ void jbd2_journal_commit_transaction(journal_t *journal)
tag->t_flags |= cpu_to_be16(JBD2_FLAG_LAST_TAG);
jbd2_descr_block_csum_set(journal, descriptor);
start_journal_io:
for (i = 0; i < bufs; i++) {
struct buffer_head *bh = wbuf[i];

37
fs/jbd2/recovery.c
View File

@ -174,6 +174,25 @@ static int jread(struct buffer_head **bhp, journal_t *journal,
return 0;
}
static int jbd2_descr_block_csum_verify(journal_t *j,
void *buf)
{
struct jbd2_journal_block_tail *tail;
__u32 provided, calculated;
if (!JBD2_HAS_INCOMPAT_FEATURE(j, JBD2_FEATURE_INCOMPAT_CSUM_V2))
return 1;
tail = (struct jbd2_journal_block_tail *)(buf + j->j_blocksize -
sizeof(struct jbd2_journal_block_tail));
provided = tail->t_checksum;
tail->t_checksum = 0;
calculated = jbd2_chksum(j, j->j_csum_seed, buf, j->j_blocksize);
tail->t_checksum = provided;
provided = be32_to_cpu(provided);
return provided == calculated;
}
/*
* Count the number of in-use tags in a journal descriptor block.
@ -186,6 +205,9 @@ static int count_tags(journal_t *journal, struct buffer_head *bh)
int nr = 0, size = journal->j_blocksize;
int tag_bytes = journal_tag_bytes(journal);
if (JBD2_HAS_INCOMPAT_FEATURE(journal, JBD2_FEATURE_INCOMPAT_CSUM_V2))
size -= sizeof(struct jbd2_journal_block_tail);
tagp = &bh->b_data[sizeof(journal_header_t)];
while ((tagp - bh->b_data + tag_bytes) <= size) {
@ -366,6 +388,7 @@ static int do_one_pass(journal_t *journal,
int blocktype;
int tag_bytes = journal_tag_bytes(journal);
__u32 crc32_sum = ~0; /* Transactional Checksums */
int descr_csum_size = 0;
/*
* First thing is to establish what we expect to find in the log
@ -451,6 +474,18 @@ static int do_one_pass(journal_t *journal,
switch(blocktype) {
case JBD2_DESCRIPTOR_BLOCK:
/* Verify checksum first */
if (JBD2_HAS_INCOMPAT_FEATURE(journal,
JBD2_FEATURE_INCOMPAT_CSUM_V2))
descr_csum_size =
sizeof(struct jbd2_journal_block_tail);
if (descr_csum_size > 0 &&
!jbd2_descr_block_csum_verify(journal,
bh->b_data)) {
err = -EIO;
goto failed;
}
/* If it is a valid descriptor block, replay it
* in pass REPLAY; if journal_checksums enabled, then
* calculate checksums in PASS_SCAN, otherwise,
@ -481,7 +516,7 @@ static int do_one_pass(journal_t *journal,
tagp = &bh->b_data[sizeof(journal_header_t)];
while ((tagp - bh->b_data + tag_bytes)
<= journal->j_blocksize) {
<= journal->j_blocksize - descr_csum_size) {
unsigned long io_block;
tag = (journal_block_tag_t *) tagp;