linux-kernel - Re: [PATCH] f2fs: fix to redirty page if fail to gc data page

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Message-ID: <a09543b8-349e-d2cc-0e15-f2bf82d4dcfa@huawei.com>
Date:	Tue, 31 May 2016 14:10:50 +0800
From:	Chao Yu <yuchao0@...wei.com>
To:	Jaegeuk Kim <jaegeuk@...nel.org>, Chao Yu <chao@...nel.org>
CC:	<linux-f2fs-devel@...ts.sourceforge.net>,
	<linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] f2fs: fix to redirty page if fail to gc data page

Hi Jaegeuk,

On 2016/5/30 10:37, Jaegeuk Kim wrote:
> Hi Chao,
> 
> On Sat, May 21, 2016 at 01:19:11PM +0800, Chao Yu wrote:
>> From: Chao Yu <yuchao0@...wei.com>
>>
>> If we fail to move data page during foreground GC, we should give another
>> chance to writeback that page which was set dirty previously by writer.
>>
>> Signed-off-by: Chao Yu <yuchao0@...wei.com>
>> ---
>>  fs/f2fs/gc.c | 5 ++++-
>>  1 file changed, 4 insertions(+), 1 deletion(-)
>>
>> diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c
>> index 38d56f6..ee213a8 100644
>> --- a/fs/f2fs/gc.c
>> +++ b/fs/f2fs/gc.c
>> @@ -653,12 +653,15 @@ static void move_data_page(struct inode *inode, block_t bidx, int gc_type)
>>  			.page = page,
>>  			.encrypted_page = NULL,
>>  		};
>> +		bool is_dirty = PageDirty(page);
>> +
>>  		set_page_dirty(page);
>>  		f2fs_wait_on_page_writeback(page, DATA, true);
>>  		if (clear_page_dirty_for_io(page))
>>  			inode_dec_dirty_pages(inode);
>>  		set_cold_data(page);
>> -		do_write_data_page(&fio);
>> +		if (do_write_data_page(&fio) && is_dirty)
>> +			set_page_dirty(page);
> 
> If this page is truncated with -ENOENT, we don't need to set it dirty again.

Agree

> I expect that, if we get an error here, do_garbage_collect() would retry FG_GC

IIRC, you have reworked the FG_GC flows changed from an infinite loop to trying
do the movement just one time. Here, I think if there are just few of blocks are
failed to be moved, we can give one more time for retrying. How do you think?

> again.
> 
> Thanks,
> 
>>  		clear_cold_data(page);
>>  	}
>>  out:
>> -- 
>> 2.7.2
> .
>