If the external journal device has metadata_csum enabled, verify
that the superblock checksum matches the block before we try to
mount.
Signed-off-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
---
fs/ext4/super.c | 9 +++++++++
1 file changed, 9 insertions(+)
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 7045f1d..222ed5d 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -4372,6 +4372,15 @@ static journal_t *ext4_get_dev_journal(struct super_block *sb,
goto out_bdev;
}
+ if ((le32_to_cpu(es->s_feature_ro_compat) &
+ EXT4_FEATURE_RO_COMPAT_METADATA_CSUM) &&
+ es->s_checksum != ext4_superblock_csum(sb, es)) {
+ ext4_msg(sb, KERN_ERR, "external journal has "
+ "corrupt superblock");
+ brelse(bh);
+ goto out_bdev;
+ }
+
if (memcmp(EXT4_SB(sb)->s_es->s_journal_uuid, es->s_uuid, 16)) {
ext4_msg(sb, KERN_ERR, "journal UUID does not match");
brelse(bh);
--
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