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Subject: Re: [PATCH] f2fs: fix to cover allocate_segment() with lock
To:     Jaegeuk Kim <jaegeuk@kernel.org>
CC:     <linux-f2fs-devel@lists.sourceforge.net>,
        <linux-kernel@vger.kernel.org>, <chao@kernel.org>
References: <20210414012134.128066-1-yuchao0@huawei.com>
 <YH22a55sexxwmGCe@google.com>
From:   Chao Yu <yuchao0@huawei.com>
Message-ID: <03dc1c69-9215-1b5f-b1cc-c38454f3b90a@huawei.com>
Date:   Tue, 20 Apr 2021 09:52:47 +0800
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On 2021/4/20 0:57, Jaegeuk Kim wrote:
> On 04/14, Chao Yu wrote:
>> As we did for other cases, in fix_curseg_write_pointer(), let's
>> change as below:
>> - use callback function s_ops->allocate_segment() instead of
>> raw function allocate_segment_by_default();
>> - cover allocate_segment() with curseg_lock and sentry_lock.
>>
>> Signed-off-by: Chao Yu <yuchao0@huawei.com>
>> ---
>>   fs/f2fs/segment.c | 7 ++++++-
>>   1 file changed, 6 insertions(+), 1 deletion(-)
>>
>> diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
>> index b2ee6b7791b0..daf9531ec58f 100644
>> --- a/fs/f2fs/segment.c
>> +++ b/fs/f2fs/segment.c
>> @@ -4848,7 +4848,12 @@ static int fix_curseg_write_pointer(struct f2fs_sb_info *sbi, int type)
>>   
>>   	f2fs_notice(sbi, "Assign new section to curseg[%d]: "
>>   		    "curseg[0x%x,0x%x]", type, cs->segno, cs->next_blkoff);
>> -	allocate_segment_by_default(sbi, type, true);
>> +
>> +	down_read(&SM_I(sbi)->curseg_lock);
>> +	down_write(&SIT_I(sbi)->sentry_lock);
>> +	SIT_I(sbi)->s_ops->allocate_segment(sbi, type, true);
>> +	up_write(&SIT_I(sbi)->sentry_lock);
>> +	up_read(&SM_I(sbi)->curseg_lock);
> 
> Seems f2fs_allocate_new_section()?

f2fs_allocate_new_section() will allocate new section only when current
section has been initialized and has valid block/ckpt_block.

It looks fix_curseg_write_pointer() wants to force migrating current segment
to new section whenever write pointer and curseg->next_blkoff is inconsistent.

So how about adding a parameter to force f2fs_allocate_new_section() to
allocate new section?

Thanks,

> 
>>   
>>   	/* check consistency of the zone curseg pointed to */
>>   	if (check_zone_write_pointer(sbi, zbd, &zone))
>> -- 
>> 2.29.2
> .
>