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authorDarrick J. Wong <darrick.wong@oracle.com>2014-08-27 18:40:07 -0400
committerTheodore Ts'o <tytso@mit.edu>2014-08-28 22:22:29 -0400
commitdb9ee220361de03ee86388f9ea5e529eaad5323c (patch)
tree1f5047f2f588e814901be723a989adde97ae5093 /fs/ext4/super.c
parent022eaa7517017efe4f6538750c2b59a804dc7df7 (diff)
jbd2: fix descriptor block size handling errors with journal_csum
It turns out that there are some serious problems with the on-disk format of journal checksum v2. The foremost is that the function to calculate descriptor tag size returns sizes that are too big. This causes alignment issues on some architectures and is compounded by the fact that some parts of jbd2 use the structure size (incorrectly) to determine the presence of a 64bit journal instead of checking the feature flags. Therefore, introduce journal checksum v3, which enlarges the descriptor block tag format to allow for full 32-bit checksums of journal blocks, fix the journal tag function to return the correct sizes, and fix the jbd2 recovery code to use feature flags to determine 64bitness. Add a few function helpers so we don't have to open-code quite so many pieces. Switching to a 16-byte block size was found to increase journal size overhead by a maximum of 0.1%, to convert a 32-bit journal with no checksumming to a 32-bit journal with checksum v3 enabled. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reported-by: TR Reardon <thomas_reardon@hotmail.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu> Cc: stable@vger.kernel.org
Diffstat (limited to 'fs/ext4/super.c')
-rw-r--r--fs/ext4/super.c5
1 files changed, 3 insertions, 2 deletions
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 32b43ad154b9..0b28b36e7915 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -3181,9 +3181,9 @@ static int set_journal_csum_feature_set(struct super_block *sb)
if (EXT4_HAS_RO_COMPAT_FEATURE(sb,
EXT4_FEATURE_RO_COMPAT_METADATA_CSUM)) {
- /* journal checksum v2 */
+ /* journal checksum v3 */
compat = 0;
- incompat = JBD2_FEATURE_INCOMPAT_CSUM_V2;
+ incompat = JBD2_FEATURE_INCOMPAT_CSUM_V3;
} else {
/* journal checksum v1 */
compat = JBD2_FEATURE_COMPAT_CHECKSUM;
@@ -3205,6 +3205,7 @@ static int set_journal_csum_feature_set(struct super_block *sb)
jbd2_journal_clear_features(sbi->s_journal,
JBD2_FEATURE_COMPAT_CHECKSUM, 0,
JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT |
+ JBD2_FEATURE_INCOMPAT_CSUM_V3 |
JBD2_FEATURE_INCOMPAT_CSUM_V2);
}