lkml.org 
[lkml]   [2022]   [Aug]   [23]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
SubjectRe: [PATCH RFC] jbd2: detect old record when do journal scan
From
Date


On 2022/8/19 17:54, Jan Kara wrote:
> On Wed 10-08-22 09:34:42, Ye Bin wrote:
>> 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@huawei.com>
> Thanks for the patch! Let me see if I understand your concern right. You
> are concerned about the following scenario:
>
> 1) Kernel uses the filesystem, there's a crash.
> 2) E2fsprogs replays the journal but fails to update sb->s_sequence in the
> journal superblock.
> 3) Kernel mounts the fs again - however note that even if kernel skips
> recovery, it does scan the journal jbd2_journal_skip_recovery() and
> journal->j_transaction_sequence is set based on the last transaction found
> in the journal.
>
> So I don't think there is really possibility we will quickly reuse some
> transaction IDs and thus possibility of corruption on replay? Am I missing
> something?
>
> Honza
The file system corruption I encountered was indeed because e2fsprogs
did not update
journal - > J_ transaction_ Sequence leads to replay the old transaction.
So I wonder whether the kernel should detect this kind of exception, at
least when there
is a file system corruption, there are clues to trace.
>
>> ---
>> 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
>>

\
 
 \ /
  Last update: 2022-08-23 13:17    [W:1.216 / U:0.132 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site