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jbd2: checksum revocation blocks 

Compute and verify revoke blocks inside the journal.

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 08:08:24 -04:00 committed by Theodore Ts'o
parent 4fd5ea43bc
commit 42a7106de6
2 changed files with 48 additions and 1 deletions
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22
fs/jbd2/recovery.c
View File

@ -706,6 +706,25 @@ static int do_one_pass(journal_t *journal,
return err;
}
static int jbd2_revoke_block_csum_verify(journal_t *j,
void *buf)
{
struct jbd2_journal_revoke_tail *tail;
__u32 provided, calculated;
if (!JBD2_HAS_INCOMPAT_FEATURE(j, JBD2_FEATURE_INCOMPAT_CSUM_V2))
return 1;
tail = (struct jbd2_journal_revoke_tail *)(buf + j->j_blocksize -
sizeof(struct jbd2_journal_revoke_tail));
provided = tail->r_checksum;
tail->r_checksum = 0;
calculated = jbd2_chksum(j, j->j_csum_seed, buf, j->j_blocksize);
tail->r_checksum = provided;
provided = be32_to_cpu(provided);
return provided == calculated;
}
/* Scan a revoke record, marking all blocks mentioned as revoked. */
@ -720,6 +739,9 @@ static int scan_revoke_records(journal_t *journal, struct buffer_head *bh,
offset = sizeof(jbd2_journal_revoke_header_t);
max = be32_to_cpu(header->r_count);
if (!jbd2_revoke_block_csum_verify(journal, header))
return -EINVAL;
if (JBD2_HAS_INCOMPAT_FEATURE(journal, JBD2_FEATURE_INCOMPAT_64BIT))
record_len = 8;

27
fs/jbd2/revoke.c
View File

@ -578,6 +578,7 @@ static void write_one_revoke_record(journal_t *journal,
struct jbd2_revoke_record_s *record,
int write_op)
{
int csum_size = 0;
struct journal_head *descriptor;
int offset;
journal_header_t *header;
@ -592,9 +593,13 @@ static void write_one_revoke_record(journal_t *journal,
descriptor = *descriptorp;
offset = *offsetp;
/* Do we need to leave space at the end for a checksum? */
if (JBD2_HAS_INCOMPAT_FEATURE(journal, JBD2_FEATURE_INCOMPAT_CSUM_V2))
csum_size = sizeof(struct jbd2_journal_revoke_tail);
/* Make sure we have a descriptor with space left for the record */
if (descriptor) {
if (offset == journal->j_blocksize) {
if (offset >= journal->j_blocksize - csum_size) {
flush_descriptor(journal, descriptor, offset, write_op);
descriptor = NULL;
}
@ -631,6 +636,24 @@ static void write_one_revoke_record(journal_t *journal,
*offsetp = offset;
}
static void jbd2_revoke_csum_set(journal_t *j,
struct journal_head *descriptor)
{
struct jbd2_journal_revoke_tail *tail;
__u32 csum;
if (!JBD2_HAS_INCOMPAT_FEATURE(j, JBD2_FEATURE_INCOMPAT_CSUM_V2))
return;
tail = (struct jbd2_journal_revoke_tail *)
(jh2bh(descriptor)->b_data + j->j_blocksize -
sizeof(struct jbd2_journal_revoke_tail));
tail->r_checksum = 0;
csum = jbd2_chksum(j, j->j_csum_seed, jh2bh(descriptor)->b_data,
j->j_blocksize);
tail->r_checksum = cpu_to_be32(csum);
}
/*
* Flush a revoke descriptor out to the journal. If we are aborting,
* this is a noop; otherwise we are generating a buffer which needs to
@ -652,6 +675,8 @@ static void flush_descriptor(journal_t *journal,
header = (jbd2_journal_revoke_header_t *) jh2bh(descriptor)->b_data;
header->r_count = cpu_to_be32(offset);
jbd2_revoke_csum_set(journal, descriptor);
set_buffer_jwrite(bh);
BUFFER_TRACE(bh, "write");
set_buffer_dirty(bh);