linux-ext4 - Re: [PATCH] ext4, jbd2: ensure panic when there is no need to record errno in the jbd2 sb

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Date:   Sat, 30 Nov 2019 11:24:48 +0800
From:   "zhangyi (F)" <yi.zhang@...wei.com>
To:     Jan Kara <jack@...e.cz>
CC:     <linux-ext4@...r.kernel.org>, <jack@...e.com>, <tytso@....edu>,
        <adilger.kernel@...ger.ca>, <liangyun2@...wei.com>
Subject: Re: [PATCH] ext4, jbd2: ensure panic when there is no need to record
 errno in the jbd2 sb

On 2019/11/29 22:46, Jan Kara wrote:
> On Tue 26-11-19 22:45:37, zhangyi (F) wrote:
>> JBD2_REC_ERR flag used to indicate the errno has been updated when jbd2
>> aborted, and then __ext4_abort() and ext4_handle_error() can invoke
>> panic if ERRORS_PANIC is specified. But there is one exception, if jbd2
>> thread failed to submit commit record, it abort journal through
>> invoking __jbd2_journal_abort_hard() without set this flag, so we can
>> no longer panic. Fix this by set such flag even if there is no need to
>> record errno in the jbd2 super block.
>>
>> Fixes: 4327ba52afd03 ("ext4, jbd2: ensure entering into panic after recording an error in superblock")
>> Signed-off-by: zhangyi (F) <yi.zhang@...wei.com>
>> Cc: <stable@...r.kernel.org>
> 
> Thanks for the patch. This indeed looks like a bug. I was trying hard to
> understand why are we actually using __jbd2_journal_abort_hard() in
> fs/jbd2/commit.c in the first place. And after some digging, I think it is
> an oversight and we should just use jbd2_journal_abort(). The calls have been
> introduced by commit 818d276ceb83a "ext4: Add the journal checksum
> feature". Before that commit, we were just using jbd2_journal_abort() when
> writing commit block failed. And when we use jbd2_journal_abort() from
> everywhere, that will also deal with the problem you've found.
> 
> Also as a nice cleanup we could then just drop __jbd2_journal_abort_hard(),
> __jbd2_journal_abort_soft() and have all the functionality in a single
> function jbd2_journal_abort().
>

Indeed, it seems that we also need to record the errno if we failed to
submit commit block, I will remove __jbd2_journal_abort_hard() and combine
them in my next iteration.

Thanks,
Yi.