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jbd2: unify revoke and tag block checksum handling
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Revoke and tag descriptor blocks are just different kinds of descriptor
blocks and thus have checksum in the same place. Unify computation and
checking of checksums for these.

Reviewed-by: Darrick J. Wong <[email protected]>
Signed-off-by: Jan Kara <[email protected]>
Signed-off-by: Theodore Ts'o <[email protected]>
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@jankara @tytso
jankara authored and tytso committed Feb 23, 2016
1 parent 32ab671 commit 1101cd4
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Showing 5 changed files with 25 additions and 66 deletions.
18 changes: 1 addition & 17 deletions fs/jbd2/commit.c
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Original file line number Diff line number Diff line change
Expand Up @@ -317,22 +317,6 @@ static void write_tag_block(journal_t *j, 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 buffer_head *bh)
{
struct jbd2_journal_block_tail *tail;
__u32 csum;

if (!jbd2_journal_has_csum_v2or3(j))
return;

tail = (struct jbd2_journal_block_tail *)(bh->b_data + j->j_blocksize -
sizeof(struct jbd2_journal_block_tail));
tail->t_checksum = 0;
csum = jbd2_chksum(j, j->j_csum_seed, bh->b_data, j->j_blocksize);
tail->t_checksum = cpu_to_be32(csum);
}

static void jbd2_block_tag_csum_set(journal_t *j, journal_block_tag_t *tag,
struct buffer_head *bh, __u32 sequence)
{
Expand Down Expand Up @@ -714,7 +698,7 @@ 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);
jbd2_descriptor_block_csum_set(journal, descriptor);
start_journal_io:
for (i = 0; i < bufs; i++) {
struct buffer_head *bh = wbuf[i];
Expand Down
15 changes: 15 additions & 0 deletions fs/jbd2/journal.c
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Original file line number Diff line number Diff line change
Expand Up @@ -834,6 +834,21 @@ jbd2_journal_get_descriptor_buffer(transaction_t *transaction, int type)
return bh;
}

void jbd2_descriptor_block_csum_set(journal_t *j, struct buffer_head *bh)
{
struct jbd2_journal_block_tail *tail;
__u32 csum;

if (!jbd2_journal_has_csum_v2or3(j))
return;

tail = (struct jbd2_journal_block_tail *)(bh->b_data + j->j_blocksize -
sizeof(struct jbd2_journal_block_tail));
tail->t_checksum = 0;
csum = jbd2_chksum(j, j->j_csum_seed, bh->b_data, j->j_blocksize);
tail->t_checksum = cpu_to_be32(csum);
}

/*
* Return tid of the oldest transaction in the journal and block in the journal
* where the transaction starts.
Expand Down
31 changes: 5 additions & 26 deletions fs/jbd2/recovery.c
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Original file line number Diff line number Diff line change
Expand Up @@ -174,8 +174,7 @@ static int jread(struct buffer_head **bhp, journal_t *journal,
return 0;
}

static int jbd2_descr_block_csum_verify(journal_t *j,
void *buf)
static int jbd2_descriptor_block_csum_verify(journal_t *j, void *buf)
{
struct jbd2_journal_block_tail *tail;
__be32 provided;
Expand Down Expand Up @@ -522,8 +521,8 @@ static int do_one_pass(journal_t *journal,
descr_csum_size =
sizeof(struct jbd2_journal_block_tail);
if (descr_csum_size > 0 &&
!jbd2_descr_block_csum_verify(journal,
bh->b_data)) {
!jbd2_descriptor_block_csum_verify(journal,
bh->b_data)) {
printk(KERN_ERR "JBD2: Invalid checksum "
"recovering block %lu in log\n",
next_log_block);
Expand Down Expand Up @@ -811,26 +810,6 @@ 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;
__be32 provided;
__u32 calculated;

if (!jbd2_journal_has_csum_v2or3(j))
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;

return provided == cpu_to_be32(calculated);
}

/* Scan a revoke record, marking all blocks mentioned as revoked. */

static int scan_revoke_records(journal_t *journal, struct buffer_head *bh,
Expand All @@ -846,11 +825,11 @@ static int scan_revoke_records(journal_t *journal, struct buffer_head *bh,
offset = sizeof(jbd2_journal_revoke_header_t);
rcount = be32_to_cpu(header->r_count);

if (!jbd2_revoke_block_csum_verify(journal, header))
if (!jbd2_descriptor_block_csum_verify(journal, header))
return -EFSBADCRC;

if (jbd2_journal_has_csum_v2or3(journal))
csum_size = sizeof(struct jbd2_journal_revoke_tail);
csum_size = sizeof(struct jbd2_journal_block_tail);
if (rcount > journal->j_blocksize - csum_size)
return -EINVAL;
max = rcount;
Expand Down
19 changes: 2 additions & 17 deletions fs/jbd2/revoke.c
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Original file line number Diff line number Diff line change
Expand Up @@ -583,7 +583,7 @@ static void write_one_revoke_record(transaction_t *transaction,

/* Do we need to leave space at the end for a checksum? */
if (jbd2_journal_has_csum_v2or3(journal))
csum_size = sizeof(struct jbd2_journal_revoke_tail);
csum_size = sizeof(struct jbd2_journal_block_tail);

if (jbd2_has_feature_64bit(journal))
sz = 8;
Expand Down Expand Up @@ -623,21 +623,6 @@ static void write_one_revoke_record(transaction_t *transaction,
*offsetp = offset;
}

static void jbd2_revoke_csum_set(journal_t *j, struct buffer_head *bh)
{
struct jbd2_journal_revoke_tail *tail;
__u32 csum;

if (!jbd2_journal_has_csum_v2or3(j))
return;

tail = (struct jbd2_journal_revoke_tail *)(bh->b_data + j->j_blocksize -
sizeof(struct jbd2_journal_revoke_tail));
tail->r_checksum = 0;
csum = jbd2_chksum(j, j->j_csum_seed, bh->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
Expand All @@ -658,7 +643,7 @@ static void flush_descriptor(journal_t *journal,

header = (jbd2_journal_revoke_header_t *)descriptor->b_data;
header->r_count = cpu_to_be32(offset);
jbd2_revoke_csum_set(journal, descriptor);
jbd2_descriptor_block_csum_set(journal, descriptor);

set_buffer_jwrite(descriptor);
BUFFER_TRACE(descriptor, "write");
Expand Down
8 changes: 2 additions & 6 deletions include/linux/jbd2.h
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Original file line number Diff line number Diff line change
Expand Up @@ -200,7 +200,7 @@ typedef struct journal_block_tag_s
__be32 t_blocknr_high; /* most-significant high 32bits. */
} journal_block_tag_t;

/* Tail of descriptor block, for checksumming */
/* Tail of descriptor or revoke block, for checksumming */
struct jbd2_journal_block_tail {
__be32 t_checksum; /* crc32c(uuid+descr_block) */
};
Expand All @@ -215,11 +215,6 @@ typedef struct jbd2_journal_revoke_header_s
__be32 r_count; /* Count of bytes used in the block */
} jbd2_journal_revoke_header_t;

/* Tail of revoke block, for checksumming */
struct jbd2_journal_revoke_tail {
__be32 r_checksum; /* crc32c(uuid+revoke_block) */
};

/* Definitions for the journal tag flags word: */
#define JBD2_FLAG_ESCAPE 1 /* on-disk block is escaped */
#define JBD2_FLAG_SAME_UUID 2 /* block has same uuid as previous */
Expand Down Expand Up @@ -1138,6 +1133,7 @@ static inline void jbd2_unfile_log_bh(struct buffer_head *bh)

/* Log buffer allocation */
struct buffer_head *jbd2_journal_get_descriptor_buffer(transaction_t *, int);
void jbd2_descriptor_block_csum_set(journal_t *, struct buffer_head *);
int jbd2_journal_next_log_block(journal_t *, unsigned long long *);
int jbd2_journal_get_log_tail(journal_t *journal, tid_t *tid,
unsigned long *block);
Expand Down

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