[PATCH RFC] jbd2: detect old record when do journal scan

[Ye Bin]

As https://github.com/tytso/e2fsprogs/issues/120 describe tune2fs do not update
j_tail_sequence when do journal recovery. This maybe recover old journal record,
then will lead to file system corruption.
To avoid file system corruption in this case, if detect current transaction's
commit time earlier than previous transaction's commit time when do journal
scan, just return error.

Signed-off-by: Ye Bin <yebin10@xxxxxxxxxx>
---
 fs/jbd2/recovery.c | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/fs/jbd2/recovery.c b/fs/jbd2/recovery.c
index f548479615c6..f3def21a96a5 100644
--- a/fs/jbd2/recovery.c
+++ b/fs/jbd2/recovery.c
@@ -812,8 +812,17 @@ static int do_one_pass(journal_t *journal,
 					break;
 				}
 			}
-			if (pass == PASS_SCAN)
+			if (pass == PASS_SCAN) {
+				if (commit_time < last_trans_commit_time) {
+					pr_err("JBD2: old journal record found "
+					       "in transaction %u\n",
+					       next_commit_ID);
+					err = -EFSBADCRC;
+					brelse(bh);
+					goto failed;
+				}
 				last_trans_commit_time = commit_time;
+			}
 			brelse(bh);
 			next_commit_ID++;
 			continue;
-- 
2.31.1