jbd2: complain about descriptor block checksum errors

We should complain in dmesg when journal recovery fails on account of
the descriptor block being corrupt, so that the diagnostic data can
be recovered.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

fs/jbd2/recovery.c

@@ -524,6 +524,9 @@ static int do_one_pass(journal_t *journal,
 			if (descr_csum_size > 0 &&
 			    !jbd2_descr_block_csum_verify(journal,
 							  bh->b_data)) {
+				printk(KERN_ERR "JBD2: Invalid checksum "
+				       "recovering block %lu in log\n",
+				       next_log_block);
 				err = -EIO;
 				brelse(bh);
 				goto failed;