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authorDarrick J. Wong <djwong@us.ibm.com>2012-05-27 08:10:22 -0400
committerTheodore Ts'o <tytso@mit.edu>2012-05-27 08:10:22 -0400
commit3caa487f53f65fd1e3950a6b6ae1709e6c43b334 (patch)
tree02ee3f18422d9ffed974eb1019e98b2ee1ade01c /fs/jbd2
parent42a7106de636ebf9c0b93d25b4230e14f5f2682e (diff)
downloadvexpress-lsk-3caa487f53f65fd1e3950a6b6ae1709e6c43b334.tar.gz
jbd2: checksum descriptor blocks
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>
Diffstat (limited to 'fs/jbd2')
-rw-r--r--fs/jbd2/commit.c25
-rw-r--r--fs/jbd2/recovery.c37
2 files changed, 60 insertions, 2 deletions
diff --git a/fs/jbd2/commit.c b/fs/jbd2/commit.c
index 69d780310ae..5d505cfd21c 100644
--- a/fs/jbd2/commit.c
+++ b/fs/jbd2/commit.c
@@ -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];
diff --git a/fs/jbd2/recovery.c b/fs/jbd2/recovery.c
index 728ecd0705d..066ee603db5 100644
--- a/fs/jbd2/recovery.c
+++ b/fs/jbd2/recovery.c
@@ -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;