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Subject: Re: [PATCH 3/3] f2fs: avoid unneeded barrier in do_checkpoint()
To:     Jaegeuk Kim <jaegeuk@kernel.org>
CC:     <linux-f2fs-devel@lists.sourceforge.net>,
        <linux-kernel@vger.kernel.org>, <chao@kernel.org>
References: <20200218102136.32150-1-yuchao0@huawei.com>
 <20200218102136.32150-3-yuchao0@huawei.com>
 <20200219025154.GB96609@google.com>
 <576f8389-ba27-b461-5466-cc62e84b5c92@huawei.com>
 <20200224220031.GC77839@google.com>
From:   Chao Yu <yuchao0@huawei.com>
Message-ID: <b4c4f60f-ada5-55c9-7d16-45cecad4d433@huawei.com>
Date:   Tue, 25 Feb 2020 14:10:06 +0800
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On 2020/2/25 6:00, Jaegeuk Kim wrote:
> On 02/19, Chao Yu wrote:
>> On 2020/2/19 10:51, Jaegeuk Kim wrote:
>>> On 02/18, Chao Yu wrote:
>>>> We don't need to wait all dirty page submitting IO twice,
>>>> remove unneeded wait step.
>>>
>>> What happens if checkpoint and other meta writs are reordered?
>>
>> checkpoint can be done as following:
>>
>> 1. All meta except last cp-park of checkpoint area.
>> 2. last cp-park of checkpoint area
>>
>> So we only need to keep barrier in between step 1 and 2, we don't need
>> to care about the write order of meta in step 1, right?
> 
> Ah, let me integrate this patch into Sahitya's patch.>
> f2fs: fix the panic in do_checkpoint()

No problem.

Thanks,

> 
>>
>> Thanks,
>>
>>>
>>>>
>>>> Signed-off-by: Chao Yu <yuchao0@huawei.com>
>>>> ---
>>>>  fs/f2fs/checkpoint.c | 2 --
>>>>  1 file changed, 2 deletions(-)
>>>>
>>>> diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c
>>>> index 751815cb4c2b..9c88fb3d255a 100644
>>>> --- a/fs/f2fs/checkpoint.c
>>>> +++ b/fs/f2fs/checkpoint.c
>>>> @@ -1384,8 +1384,6 @@ static int do_checkpoint(struct f2fs_sb_info *sbi, struct cp_control *cpc)
>>>>  
>>>>  	/* Flush all the NAT/SIT pages */
>>>>  	f2fs_sync_meta_pages(sbi, META, LONG_MAX, FS_CP_META_IO);
>>>> -	/* Wait for all dirty meta pages to be submitted for IO */
>>>> -	f2fs_wait_on_all_pages(sbi, F2FS_DIRTY_META);
>>>>  
>>>>  	/*
>>>>  	 * modify checkpoint
>>>> -- 
>>>> 2.18.0.rc1
>>> .
>>>
> .
>