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Subject: Re: [f2fs-dev] [PATCH] f2fs: fix checkpoint mount option wrong
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To:     Daeho Jeong <daeho43@gmail.com>, Jaegeuk Kim <jaegeuk@kernel.org>
CC:     <kernel-team@android.com>, Daeho Jeong <daehojeong@google.com>,
        <linux-f2fs-devel@lists.sourceforge.net>,
        <linux-kernel@vger.kernel.org>
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From:   Chao Yu <yuchao0@huawei.com>
Message-ID: <042aae34-7e52-bdcc-1154-4ea1ecace39b@huawei.com>
Date:   Tue, 2 Feb 2021 09:32:06 +0800
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On 2021/2/2 8:41, Daeho Jeong wrote:
> For less confusion, I am going to separate the "merge" option from

Agreed.

> "checkpoint=".
> I am adding another "ckpt_merge" option. :)

Not sure, maybe "checkpoint_merge" will be better?

"ckpt_merge" looks more like a term only developer knew.

Thanks,

> 
> 2021년 2월 2일 (화) 오전 8:33, Daeho Jeong <daeho43@gmail.com>님이 작성:
>>
>> The rightmost one is the final option. And checkpoint=merge means
>> checkpoint is enabled with a checkpoint thread.
>>
>> mount checkpoint=disable,checkpoint=merge => checkpoint=merge
>> remount checkpoint=enable,checkpoint=merge => checkpoint=merge
>> remount checkpoint=merge,checkpoint=disable => checkpoint=disable
>> remount checkpoint=merge,checkpoint=enable => checkpoint=enable
>>
>> Like
>>
>> mount fsync_mode=posix, fsync_mode=strict, fsync_mode=nobarrier =>
>> fsync_mode=nobarrier
>>
>> 2021년 2월 2일 (화) 오전 5:11, Jaegeuk Kim <jaegeuk@kernel.org>님이 작성:
>>>
>>> On 02/01, Daeho Jeong wrote:
>>>> Actually, I think we need to select one among them, disable, enable
>>>> and merge. I realized my previous understanding about that was wrong.
>>>> In that case of "checkpoint=merge,checkpoint=enable", the last option
>>>> will override the ones before that.
>>>> This is how the other mount options like fsync_mode, whint_mode and etc.
>>>> So, the answer will be "checkpoint=enable". What do you think?
>>>
>>> We need to clarify a bit more. :)
>>>
>>> mount checkpoint=disable,checkpoint=merge
>>> remount checkpoint=enable,checkpoint=merge
>>>
>>> Then, is it going to enable checkpoint with a thread?
>>>
>>>>
>>>>
>>>>
>>>> 2021년 2월 1일 (월) 오후 9:40, Chao Yu <chao@kernel.org>님이 작성:
>>>>>
>>>>> On 2021/2/1 8:06, Daeho Jeong wrote:
>>>>>> From: Daeho Jeong <daehojeong@google.com>
>>>>>>
>>>>>> As checkpoint=merge comes in, mount option setting related to
>>>>>> checkpoint had been mixed up. Fixed it.
>>>>>>
>>>>>> Signed-off-by: Daeho Jeong <daehojeong@google.com>
>>>>>> ---
>>>>>>    fs/f2fs/super.c | 11 +++++------
>>>>>>    1 file changed, 5 insertions(+), 6 deletions(-)
>>>>>>
>>>>>> diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
>>>>>> index 56696f6cfa86..8231c888c772 100644
>>>>>> --- a/fs/f2fs/super.c
>>>>>> +++ b/fs/f2fs/super.c
>>>>>> @@ -930,20 +930,25 @@ static int parse_options(struct super_block *sb, char *options, bool is_remount)
>>>>>>                                return -EINVAL;
>>>>>>                        F2FS_OPTION(sbi).unusable_cap_perc = arg;
>>>>>>                        set_opt(sbi, DISABLE_CHECKPOINT);
>>>>>> +                     clear_opt(sbi, MERGE_CHECKPOINT);
>>>>>>                        break;
>>>>>>                case Opt_checkpoint_disable_cap:
>>>>>>                        if (args->from && match_int(args, &arg))
>>>>>>                                return -EINVAL;
>>>>>>                        F2FS_OPTION(sbi).unusable_cap = arg;
>>>>>>                        set_opt(sbi, DISABLE_CHECKPOINT);
>>>>>> +                     clear_opt(sbi, MERGE_CHECKPOINT);
>>>>>>                        break;
>>>>>>                case Opt_checkpoint_disable:
>>>>>>                        set_opt(sbi, DISABLE_CHECKPOINT);
>>>>>> +                     clear_opt(sbi, MERGE_CHECKPOINT);
>>>>>>                        break;
>>>>>>                case Opt_checkpoint_enable:
>>>>>>                        clear_opt(sbi, DISABLE_CHECKPOINT);
>>>>>> +                     clear_opt(sbi, MERGE_CHECKPOINT);
>>>>>
>>>>> What if: -o checkpoint=merge,checkpoint=enable
>>>>>
>>>>> Can you please explain the rule of merge/disable/enable combination and their
>>>>> result? e.g.
>>>>> checkpoint=merge,checkpoint=enable
>>>>> checkpoint=enable,checkpoint=merge
>>>>> checkpoint=merge,checkpoint=disable
>>>>> checkpoint=disable,checkpoint=merge
>>>>>
>>>>> If the rule/result is clear, it should be documented.
>>>>>
>>>>> Thanks,
>>>>>
>>>>>
>>>>>>                        break;
>>>>>>                case Opt_checkpoint_merge:
>>>>>> +                     clear_opt(sbi, DISABLE_CHECKPOINT);
>>>>>>                        set_opt(sbi, MERGE_CHECKPOINT);
>>>>>>                        break;
>>>>>>    #ifdef CONFIG_F2FS_FS_COMPRESSION
>>>>>> @@ -1142,12 +1147,6 @@ static int parse_options(struct super_block *sb, char *options, bool is_remount)
>>>>>>                return -EINVAL;
>>>>>>        }
>>>>>>
>>>>>> -     if (test_opt(sbi, DISABLE_CHECKPOINT) &&
>>>>>> -                     test_opt(sbi, MERGE_CHECKPOINT)) {
>>>>>> -             f2fs_err(sbi, "checkpoint=merge cannot be used with checkpoint=disable\n");
>>>>>> -             return -EINVAL;
>>>>>> -     }
>>>>>> -
>>>>>>        /* Not pass down write hints if the number of active logs is lesser
>>>>>>         * than NR_CURSEG_PERSIST_TYPE.
>>>>>>         */
>>>>>>
>>>>
>>>>
>>>> _______________________________________________
>>>> Linux-f2fs-devel mailing list
>>>> Linux-f2fs-devel@lists.sourceforge.net
>>>> https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel
> 
> 
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