linux-kernel - Re: [f2fs-dev] [PATCH] f2fs: don't clear CP_QUOTA_NEED_FSCK

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Message-ID: <29a4fd24-6340-41df-7199-6e89b70c6341@huawei.com>
Date:   Mon, 18 Feb 2019 17:10:25 +0800
From:   Chao Yu <yuchao0@...wei.com>
To:     Jaegeuk Kim <jaegeuk@...nel.org>
CC:     <linux-kernel@...r.kernel.org>,
        <linux-f2fs-devel@...ts.sourceforge.net>
Subject: Re: [f2fs-dev] [PATCH] f2fs: don't clear CP_QUOTA_NEED_FSCK_FLAG

On 2019/2/16 12:55, Jaegeuk Kim wrote:
> On 02/13, Chao Yu wrote:
>> On 2019/2/12 10:33, Jaegeuk Kim wrote:
>>> If we met this once, let fsck.f2fs clear this only.
>>> Note that, this addresses all the subtle fault injection test.
>>>
>>> Signed-off-by: Jaegeuk Kim <jaegeuk@...nel.org>
>>> ---
>>>  fs/f2fs/checkpoint.c | 2 --
>>>  1 file changed, 2 deletions(-)
>>>
>>> diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c
>>> index 03fea4efd64b..10a3ada28715 100644
>>> --- a/fs/f2fs/checkpoint.c
>>> +++ b/fs/f2fs/checkpoint.c
>>> @@ -1267,8 +1267,6 @@ static void update_ckpt_flags(struct f2fs_sb_info *sbi, struct cp_control *cpc)
>>>  
>>>  	if (is_sbi_flag_set(sbi, SBI_QUOTA_SKIP_FLUSH))
>>>  		__set_ckpt_flags(ckpt, CP_QUOTA_NEED_FSCK_FLAG);
>>> -	else
>>> -		__clear_ckpt_flags(ckpt, CP_QUOTA_NEED_FSCK_FLAG);
>>
>> I didn't get it, previously, if we didn't persist all quota file's data in
>> checkpoint, then we will tag CP_QUOTA_NEED_FSCK_FLAG in CP area, but in current
>> checkpoint, we have persisted all quota file's data, quota files are consistent
>> with all other files in filesystem, why we can't remove this NEED_FSCK flag..?
> 
> I said it's subtle. So, I guessed 1) set CP_QUOTA_NEED_FSCK_FLAG, 2) clear

I know it's subtle... and I agreed we can fix it like this in upstream
first, but in our product, it's not rare that we hit the
QUOTA_SKIP_FLUSH(its value is 4) case, later we may encounter long latency
caused by quota repairing of fsck.

> SBI_QUOTA_SKIP_FLUSH by checkpoint, 3) clear CP_QUOTA_NEED_FSCK_FLAG by another
> checkpoint?

But later if QUOTA_NEED_REPAIR is set, we will set QUOTA_NEED_FSCK_FLAG
again, right?

if (is_sbi_flag_set(sbi, SBI_QUOTA_NEED_REPAIR))
	__set_ckpt_flags(ckpt, CP_QUOTA_NEED_FSCK_FLAG);


So in order to figure out whether this is caused by out-of-order execution
of below assignments:

	if (is_sbi_flag_set(sbi, SBI_QUOTA_SKIP_FLUSH))
		__set_ckpt_flags(ckpt, CP_QUOTA_NEED_FSCK_FLAG);
	else
		__clear_ckpt_flags(ckpt, CP_QUOTA_NEED_FSCK_FLAG); --- clear flag later

	if (is_sbi_flag_set(sbi, SBI_QUOTA_NEED_REPAIR))
		__set_ckpt_flags(ckpt, CP_QUOTA_NEED_FSCK_FLAG); --- set flag first


Could you have a try:

	if (is_sbi_flag_set(sbi, SBI_QUOTA_NEED_REPAIR) ||
			is_sbi_flag_set(sbi, SBI_QUOTA_SKIP_FLUSH))
		__set_ckpt_flags(ckpt, CP_QUOTA_NEED_FSCK_FLAG);
	else
		__clear_ckpt_flags(ckpt, CP_QUOTA_NEED_FSCK_FLAG);

Thanks,

> 
>>
>> Thanks,
>>
>>>  
>>>  	if (is_sbi_flag_set(sbi, SBI_QUOTA_NEED_REPAIR))
>>>  		__set_ckpt_flags(ckpt, CP_QUOTA_NEED_FSCK_FLAG);
>>>
> 
> .
>