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Message-ID: <20120306205007.1663.15336.stgit@elm3b70.beaverton.ibm.com>
Date: Tue, 06 Mar 2012 12:50:07 -0800
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 18/23] jbd2: Checksum journal superblock
Calculate and verify a checksum covering the journal superblock.
Signed-off-by: Darrick J. Wong <djwong@...ibm.com>
---
fs/jbd2/journal.c | 50 ++++++++++++++++++++++++++++++++++++++++++++++++++
include/linux/jbd2.h | 3 +++
2 files changed, 53 insertions(+), 0 deletions(-)
diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c
index 554f899..808654a 100644
--- a/fs/jbd2/journal.c
+++ b/fs/jbd2/journal.c
@@ -109,6 +109,34 @@ int jbd2_verify_csum_type(journal_t *j, journal_superblock_t *sb)
return sb->s_checksum_type == JBD2_CRC32C_CHKSUM;
}
+static __u32 jbd2_superblock_csum(journal_t *j, journal_superblock_t *sb)
+{
+ __u32 csum, old_csum;
+
+ old_csum = sb->s_checksum;
+ sb->s_checksum = 0;
+ csum = jbd2_chksum(j, ~0, (char *)sb, sizeof(journal_superblock_t));
+ sb->s_checksum = old_csum;
+
+ return cpu_to_be32(csum);
+}
+
+int jbd2_superblock_csum_verify(journal_t *j, journal_superblock_t *sb)
+{
+ if (!JBD2_HAS_INCOMPAT_FEATURE(j, JBD2_FEATURE_INCOMPAT_CSUM_V2))
+ return 1;
+
+ return sb->s_checksum == jbd2_superblock_csum(j, sb);
+}
+
+void jbd2_superblock_csum_set(journal_t *j, journal_superblock_t *sb)
+{
+ if (!JBD2_HAS_INCOMPAT_FEATURE(j, JBD2_FEATURE_INCOMPAT_CSUM_V2))
+ return;
+
+ sb->s_checksum = jbd2_superblock_csum(j, sb);
+}
+
/*
* Helper function used to manage commit timeouts
*/
@@ -1178,6 +1206,7 @@ void jbd2_journal_update_superblock(journal_t *journal, int wait)
sb->s_sequence = cpu_to_be32(journal->j_tail_sequence);
sb->s_start = cpu_to_be32(journal->j_tail);
sb->s_errno = cpu_to_be32(journal->j_errno);
+ jbd2_superblock_csum_set(journal, sb);
read_unlock(&journal->j_state_lock);
BUFFER_TRACE(bh, "marking dirty");
@@ -1295,6 +1324,17 @@ static int journal_get_superblock(journal_t *journal)
}
}
+ /* Check superblock checksum */
+ if (!jbd2_superblock_csum_verify(journal, sb)) {
+ printk(KERN_ERR "JBD: journal checksum error\n");
+ goto out;
+ }
+
+ /* Precompute checksum seed for all metadata */
+ if (JBD2_HAS_INCOMPAT_FEATURE(journal, JBD2_FEATURE_INCOMPAT_CSUM_V2))
+ journal->j_csum_seed = jbd2_chksum(journal, ~0, sb->s_uuid,
+ sizeof(sb->s_uuid));
+
set_buffer_verified(bh);
return 0;
@@ -1581,6 +1621,13 @@ int jbd2_journal_set_features (journal_t *journal, unsigned long compat,
return 0;
}
}
+
+ /* Precompute checksum seed for all metadata */
+ if (JBD2_HAS_INCOMPAT_FEATURE(journal,
+ JBD2_FEATURE_INCOMPAT_CSUM_V2))
+ journal->j_csum_seed = jbd2_chksum(journal, ~0,
+ sb->s_uuid,
+ sizeof(sb->s_uuid));
}
/* If enabling v1 checksums, downgrade superblock */
@@ -1591,6 +1638,7 @@ int jbd2_journal_set_features (journal_t *journal, unsigned long compat,
sb->s_feature_compat |= cpu_to_be32(compat);
sb->s_feature_ro_compat |= cpu_to_be32(ro);
sb->s_feature_incompat |= cpu_to_be32(incompat);
+ jbd2_journal_update_superblock(journal, 0);
return 1;
#undef COMPAT_FEATURE_ON
@@ -1621,6 +1669,7 @@ void jbd2_journal_clear_features(journal_t *journal, unsigned long compat,
sb->s_feature_compat &= ~cpu_to_be32(compat);
sb->s_feature_ro_compat &= ~cpu_to_be32(ro);
sb->s_feature_incompat &= ~cpu_to_be32(incompat);
+ jbd2_journal_update_superblock(journal, 0);
}
EXPORT_SYMBOL(jbd2_journal_clear_features);
@@ -1669,6 +1718,7 @@ static int journal_convert_superblock_v1(journal_t *journal,
sb->s_nr_users = cpu_to_be32(1);
sb->s_header.h_blocktype = cpu_to_be32(JBD2_SUPERBLOCK_V2);
+ jbd2_superblock_csum_set(journal, sb);
journal->j_format_version = 2;
bh = journal->j_sb_buffer;
diff --git a/include/linux/jbd2.h b/include/linux/jbd2.h
index 320de7d..f321226 100644
--- a/include/linux/jbd2.h
+++ b/include/linux/jbd2.h
@@ -969,6 +969,9 @@ struct journal_s
/* Reference to checksum algorithm driver via cryptoapi */
struct crypto_shash *j_chksum_driver;
+
+ /* Precomputed journal UUID checksum for seeding other checksums */
+ __u32 j_csum_seed;
};
/*
--
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