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Message-ID: <20111008075635.20506.77591.stgit@elm3c44.beaverton.ibm.com>
Date: Sat, 08 Oct 2011 00:56:35 -0700
From: "Darrick J. Wong" <djwong@...ibm.com>
To: Andreas Dilger <adilger.kernel@...ger.ca>,
Theodore Tso <tytso@....edu>,
"Darrick J. Wong" <djwong@...ibm.com>
Cc: Sunil Mushran <sunil.mushran@...cle.com>,
Martin K Petersen <martin.petersen@...cle.com>,
Greg Freemyer <greg.freemyer@...il.com>,
Amir Goldstein <amir73il@...il.com>,
linux-kernel <linux-kernel@...r.kernel.org>,
Andi Kleen <andi@...stfloor.org>,
Mingming Cao <cmm@...ibm.com>,
Joel Becker <jlbec@...lplan.org>,
linux-fsdevel <linux-fsdevel@...r.kernel.org>,
linux-ext4@...r.kernel.org, Coly Li <colyli@...il.com>
Subject: [PATCH 26/28] jbd2: Checksum descriptor blocks
Calculate and verify a checksum of each descriptor block.
Signed-off-by: Darrick J. Wong <djwong@...ibm.com>
---
fs/jbd2/commit.c | 26 ++++++++++++++++++++++++--
fs/jbd2/recovery.c | 37 ++++++++++++++++++++++++++++++++++++-
include/linux/jbd2.h | 5 +++++
3 files changed, 65 insertions(+), 3 deletions(-)
diff --git a/fs/jbd2/commit.c b/fs/jbd2/commit.c
index eef6979..e2c355c 100644
--- a/fs/jbd2/commit.c
+++ b/fs/jbd2/commit.c
@@ -302,6 +302,24 @@ 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 crc;
+
+ 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;
+ crc = jbd2_chksum(j, j->j_uuid_crc, jh2bh(descriptor)->b_data,
+ j->j_blocksize);
+ tail->t_checksum = cpu_to_be32(crc);
+}
+
/*
* jbd2_journal_commit_transaction
*
@@ -331,6 +349,10 @@ void jbd2_journal_commit_transaction(journal_t *journal)
struct buffer_head *cbh = NULL; /* For transactional checksums */
__u32 crc32_sum = ~0;
struct blk_plug plug;
+ int csum_size = 0;
+
+ if (JBD2_HAS_INCOMPAT_FEATURE(j, JBD2_FEATURE_INCOMPAT_CSUM_V2))
+ csum_size = sizeof(struct jbd2_journal_block_tail);
/*
* First job: lock down the current transaction and wait for
@@ -623,7 +645,7 @@ 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, "JBD: Submit %d IOs\n", bufs);
@@ -632,7 +654,7 @@ void jbd2_journal_commit_transaction(journal_t *journal)
the last tag we set up. */
tag->t_flags |= cpu_to_be32(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 4f4eda4..ecb1eda 100644
--- a/fs/jbd2/recovery.c
+++ b/fs/jbd2/recovery.c
@@ -173,6 +173,25 @@ 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_uuid_crc, 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.
@@ -185,6 +204,9 @@ 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) {
@@ -363,6 +385,7 @@ 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
@@ -448,6 +471,18 @@ 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,
@@ -478,7 +513,7 @@ 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;
diff --git a/include/linux/jbd2.h b/include/linux/jbd2.h
index 125d5be..69e305d 100644
--- a/include/linux/jbd2.h
+++ b/include/linux/jbd2.h
@@ -184,6 +184,11 @@ typedef struct journal_block_tag_s
#define JBD2_TAG_SIZE32 (offsetof(journal_block_tag_t, t_blocknr_high))
#define JBD2_TAG_SIZE64 (sizeof(journal_block_tag_t))
+/* Tail of descriptor block, for checksumming */
+struct jbd2_journal_block_tail {
+ __be32 t_checksum; /* crc32c(uuid+descr_block) */
+};
+
/*
* The revoke descriptor: used on disk to describe a series of blocks to
* be revoked from the log
--
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