linux-kernel - Re: [PATCH] f2fs: change the codes of checking CP_CRC_RECOVERY

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Date:   Fri, 24 Feb 2017 19:11:56 +0800
From:   Yunlong Song <yunlong.song@...wei.com>
To:     Chao Yu <yuchao0@...wei.com>, <jaegeuk@...nel.org>,
        <cm224.lee@...sung.com>, <chao@...nel.org>, <sylinux@....com>,
        <miaoxie@...wei.com>
CC:     <bintian.wang@...wei.com>, <linux-fsdevel@...r.kernel.org>,
        <linux-f2fs-devel@...ts.sourceforge.net>,
        <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] f2fs: change the codes of checking CP_CRC_RECOVERY_FLAG
 to macro

I think we do not need to care about the CP_CRC_RECOVERY_FLAG status of old image, I mean we
do not need to check the already-been-written node footer in the image, what we care about is the
on-going-to-write node footer, which is used for recovery.

If  CP_CRC_RECOVERY_FLAG is defined, then __set_ckpt_flags(ckpt, CP_CRC_RECOVERY_FLAG); is
executed in each do_checkpoint actually, and CP will have that flag for each on-going-to-write node footer.
I think the recovery process only needs to use the on-going-to-write node rather than the already-been-written
node in the old image. The  already-been-written node in the old image should not appear in the node
chain of recovery process, right?

On 2017/2/24 18:29, Chao Yu wrote:
> On 2017/2/24 18:06, Yunlong Song wrote:
>> No need to check the "if" condition each time, just change it to macro codes.
> We're going to check flag in CP, not just in code of f2fs.
>
> Thanks,
>
>> Signed-off-by: Yunlong Song <yunlong.song@...wei.com>
>> ---
>>  fs/f2fs/node.h    | 20 ++++++++++----------
>>  fs/f2fs/segment.c |  5 +++--
>>  2 files changed, 13 insertions(+), 12 deletions(-)
>>
>> diff --git a/fs/f2fs/node.h b/fs/f2fs/node.h
>> index 3fc9c4b..3e5a58b 100644
>> --- a/fs/f2fs/node.h
>> +++ b/fs/f2fs/node.h
>> @@ -303,11 +303,11 @@ static inline void fill_node_footer_blkaddr(struct page *page, block_t blkaddr)
>>  	size_t crc_offset = le32_to_cpu(ckpt->checksum_offset);
>>  	__u64 cp_ver = le64_to_cpu(ckpt->checkpoint_ver);
>>  
>> -	if (__is_set_ckpt_flags(ckpt, CP_CRC_RECOVERY_FLAG)) {
>> -		__u64 crc = le32_to_cpu(*((__le32 *)
>> -				((unsigned char *)ckpt + crc_offset)));
>> -		cp_ver |= (crc << 32);
>> -	}
>> +#ifdef CP_CRC_RECOVERY_FLAG
>> +	__u64 crc = le32_to_cpu(*((__le32 *)
>> +			((unsigned char *)ckpt + crc_offset)));
>> +	cp_ver |= (crc << 32);
>> +#endif
>>  	rn->footer.cp_ver = cpu_to_le64(cp_ver);
>>  	rn->footer.next_blkaddr = cpu_to_le32(blkaddr);
>>  }
>> @@ -318,11 +318,11 @@ static inline bool is_recoverable_dnode(struct page *page)
>>  	size_t crc_offset = le32_to_cpu(ckpt->checksum_offset);
>>  	__u64 cp_ver = cur_cp_version(ckpt);
>>  
>> -	if (__is_set_ckpt_flags(ckpt, CP_CRC_RECOVERY_FLAG)) {
>> -		__u64 crc = le32_to_cpu(*((__le32 *)
>> -				((unsigned char *)ckpt + crc_offset)));
>> -		cp_ver |= (crc << 32);
>> -	}
>> +#ifdef CP_CRC_RECOVERY_FLAG
>> +	__u64 crc = le32_to_cpu(*((__le32 *)
>> +			((unsigned char *)ckpt + crc_offset)));
>> +	cp_ver |= (crc << 32);
>> +#endif
>>  	return cp_ver == cpver_of_node(page);
>>  }
>>  
>> diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
>> index 9eb6d89..6c2e1ee 100644
>> --- a/fs/f2fs/segment.c
>> +++ b/fs/f2fs/segment.c
>> @@ -1573,9 +1573,10 @@ static void allocate_segment_by_default(struct f2fs_sb_info *sbi,
>>  {
>>  	if (force)
>>  		new_curseg(sbi, type, true);
>> -	else if (!is_set_ckpt_flags(sbi, CP_CRC_RECOVERY_FLAG) &&
>> -					type == CURSEG_WARM_NODE)
>> +#ifndef CP_CRC_RECOVERY_FLAG
>> +	else if (type == CURSEG_WARM_NODE)
>>  		new_curseg(sbi, type, false);
>> +#endif
>>  	else if (need_SSR(sbi) && get_ssr_segment(sbi, type))
>>  		change_curseg(sbi, type, true);
>>  	else
>>
>
> .
>


-- 
Thanks,
Yunlong Song