Re: [Bug report] journal data mode trigger panic in jbd2_journal_commit_transaction

[yangerkun <yangerkun@huawei.com>]

在 2020/11/16 21:50, Mauricio Oliveira 写道:
> Hi Kun,
> 
> On Sat, Nov 14, 2020 at 5:18 AM yangerkun <yangerkun@huawei.com> wrote:
>> While using ext4 with data=journal(3.10 kernel), we meet a problem that
>> we think may never happend...
> [...]
> 
> Could you please confirm you mean 5.10-rc* kernel instead of 3.10?
> (It seems so as you mention a recent commit below.)  Thanks!
> 
>> For now, what I have seen that can dirty buffer directly is
>> ext4_page_mkwrite(64a9f1449950 ("ext4: data=journal: fixes for
>> ext4_page_mkwrite()")), and runing ext4_punch_hole with keep_size
>> /ext4_page_mkwrite parallel can trigger above warning easily.
> [...]
> 
> 

Hi,

Sorry for the long delay reply... And thanks a lot for your advise! The 
bug trigger with a very low probability. So won't trigger with 5.10 can 
not prove no bug exist in 5.10.

Google a lot and notice that someone before has report the same bug[1]. 
'3b136499e906 ("ext4: fix data corruption in data=journal mode")' seems 
fix the problem. I will try to understand this, and give a analysis 
about how to reproduce it!

Thanks,
Kun.