linux-kernel - Re: [f2fs-dev] [PATCH 1/2] f2fs: use crc and cp version to determine roll-forward recovery

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Date:   Sat, 24 Sep 2016 14:00:41 +0800
From:   Chao Yu <yuchao0@...wei.com>
To:     Jaegeuk Kim <jaegeuk@...nel.org>, Chao Yu <chao@...nel.org>
CC:     <linux-kernel@...r.kernel.org>, <linux-fsdevel@...r.kernel.org>,
        <linux-f2fs-devel@...ts.sourceforge.net>
Subject: Re: [f2fs-dev] [PATCH 1/2] f2fs: use crc and cp version to determine
 roll-forward recovery

On 2016/9/21 8:45, Jaegeuk Kim wrote:
> @@ -259,40 +290,26 @@ static inline void fill_node_footer_blkaddr(struct page *page, block_t blkaddr)
>  {
>  	struct f2fs_checkpoint *ckpt = F2FS_CKPT(F2FS_P_SB(page));
>  	struct f2fs_node *rn = F2FS_NODE(page);
> +	size_t crc_offset = le32_to_cpu(ckpt->checksum_offset);
> +	__u64 cp_ver = le64_to_cpu(ckpt->checkpoint_ver);
> +	__u64 crc;
>  
> -	rn->footer.cp_ver = ckpt->checkpoint_ver;
> +	crc = le32_to_cpu(*((__le32 *)((unsigned char *)ckpt + crc_offset)));
> +	cp_ver |= (crc << 32);

How about using '^=' here?

> +	rn->footer.cp_ver = cpu_to_le64(cp_ver);
>  	rn->footer.next_blkaddr = cpu_to_le32(blkaddr);
>  }
>  
> -static inline nid_t ino_of_node(struct page *node_page)
> -{
> -	struct f2fs_node *rn = F2FS_NODE(node_page);
> -	return le32_to_cpu(rn->footer.ino);
> -}
> -
> -static inline nid_t nid_of_node(struct page *node_page)
> -{
> -	struct f2fs_node *rn = F2FS_NODE(node_page);
> -	return le32_to_cpu(rn->footer.nid);
> -}
> -
> -static inline unsigned int ofs_of_node(struct page *node_page)
> -{
> -	struct f2fs_node *rn = F2FS_NODE(node_page);
> -	unsigned flag = le32_to_cpu(rn->footer.flag);
> -	return flag >> OFFSET_BIT_SHIFT;
> -}
> -
> -static inline unsigned long long cpver_of_node(struct page *node_page)
> +static inline bool is_recoverable_dnode(struct page *page)
>  {
> -	struct f2fs_node *rn = F2FS_NODE(node_page);
> -	return le64_to_cpu(rn->footer.cp_ver);
> -}
> +	struct f2fs_checkpoint *ckpt = F2FS_CKPT(F2FS_P_SB(page));
> +	size_t crc_offset = le32_to_cpu(ckpt->checksum_offset);
> +	__u64 cp_ver = cur_cp_version(ckpt);
> +	__u64 crc;
>  
> -static inline block_t next_blkaddr_of_node(struct page *node_page)
> -{
> -	struct f2fs_node *rn = F2FS_NODE(node_page);
> -	return le32_to_cpu(rn->footer.next_blkaddr);
> +	crc = le32_to_cpu(*((__le32 *)((unsigned char *)ckpt + crc_offset)));
> +	cp_ver |= (crc << 32);
> +	return cpu_to_le64(cp_ver) == cpver_of_node(page);
>  }

cpu_to_le64(cp_ver) == cpver_of_node(page) ^ (crc << 32)

Thanks,