Re: [f2fs-dev][RFC PATCH 03/10] f2fs: introduce f2fs_map_bh to clean codes of check_extent_cache

[Jaegeuk Kim]

Hi Chao,

On Mon, Jan 12, 2015 at 03:11:04PM +0800, Chao Yu wrote:
> This patch introduces f2fs_map_bh to clean codes of check_extent_cache.
> 
> Signed-off-by: Chao Yu <chao2.yu@xxxxxxxxxxx>
> ---
>  fs/f2fs/data.c | 42 ++++++++++++++++++++++++++++--------------
>  1 file changed, 28 insertions(+), 14 deletions(-)
> 
> diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
> index 935a23b..5a3e489 100644
> --- a/fs/f2fs/data.c
> +++ b/fs/f2fs/data.c
> @@ -248,8 +248,30 @@ int f2fs_reserve_block(struct dnode_of_data *dn, pgoff_t index)
>  	return err;
>  }
>  
> +static void f2fs_map_bh(struct inode *inode, pgoff_t pgofs,
> +			struct extent_info *ei, struct buffer_head *bh_result)
> +{
> +	unsigned int blkbits = inode->i_sb->s_blocksize_bits;
> +	pgoff_t start_fofs, end_fofs;
> +	block_t start_blkaddr;
> +	size_t count;
> +
> +	start_fofs = ei->fofs;
> +	end_fofs = ei->fofs + ei->len - 1;
> +	start_blkaddr = ei->blk;
> +
> +	clear_buffer_new(bh_result);
> +	map_bh(bh_result, inode->i_sb,
> +			start_blkaddr + pgofs - start_fofs);
> +	count = end_fofs - pgofs + 1;

How about cleaning this codes like this?

static void f2fs_map_bh(struct super_block *sb, pgoff_t pgofs,
                       struct extent_info *ei, struct buffer_head *bh_result)
{
       unsigned int blkbits = sb->s_blocksize_bits;
       size_t count;
	
       clear_buffer_new(bh_result);
       map_bh(bh_result, sb, ei->blk + pgofs - ei->fofs);
       count = ei->fofs + ei->len  - pgofs;
       if (count < (UINT_MAX >> blkbits))
               bh_result->b_size = (count << blkbits);
       else
               bh_result->b_size = UINT_MAX;
}
	
> +	if (count < (UINT_MAX >> blkbits))
> +		bh_result->b_size = (count << blkbits);
> +	else
> +		bh_result->b_size = UINT_MAX;
> +}
> +
>  static int check_extent_cache(struct inode *inode, pgoff_t pgofs,
> -					struct buffer_head *bh_result)
> +					struct extent_info *ei)
>  {
>  	struct f2fs_inode_info *fi = F2FS_I(inode);
>  	pgoff_t start_fofs, end_fofs;
> @@ -271,18 +293,7 @@ static int check_extent_cache(struct inode *inode, pgoff_t pgofs,
>  	start_blkaddr = fi->ext.blk;
>  
>  	if (pgofs >= start_fofs && pgofs <= end_fofs) {
> -		unsigned int blkbits = inode->i_sb->s_blocksize_bits;
> -		size_t count;
> -
> -		clear_buffer_new(bh_result);
> -		map_bh(bh_result, inode->i_sb,
> -				start_blkaddr + pgofs - start_fofs);
> -		count = end_fofs - pgofs + 1;
> -		if (count < (UINT_MAX >> blkbits))
> -			bh_result->b_size = (count << blkbits);
> -		else
> -			bh_result->b_size = UINT_MAX;
> -
> +		*ei = fi->ext;
>  		stat_inc_read_hit(inode->i_sb);
>  		read_unlock(&fi->ext_lock);
>  		return 1;
> @@ -608,13 +619,16 @@ static int __get_data_block(struct inode *inode, sector_t iblock,
>  	int mode = create ? ALLOC_NODE : LOOKUP_NODE_RA;
>  	pgoff_t pgofs, end_offset;
>  	int err = 0, ofs = 1;
> +	struct extent_info ei;
>  	bool allocated = false;
>  
>  	/* Get the page offset from the block offset(iblock) */
>  	pgofs =	(pgoff_t)(iblock >> (PAGE_CACHE_SHIFT - blkbits));
>  
> -	if (check_extent_cache(inode, pgofs, bh_result))
> +	if (check_extent_cache(inode, pgofs, &ei)) {
> +		f2fs_map_bh(inode, pgofs, &ei, bh_result);
>  		goto out;
> +	}
>  
>  	if (create) {
>  		f2fs_balance_fs(F2FS_I_SB(inode));
> -- 
> 2.2.1
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