Hi,

2013-10-22 (화), 17:28 +0800, Chao Yu:
> Previously, check_block_count check valid_map with bit data type in common
> scenario that sit has all ones or zeros bitmap, it makes low mount
> performance.
> So let's check the special bitmap with integer data type instead of the bit
> one.
> 
> Signed-off-by: Tan Shu <shu....@samsung.com>
> Signed-off-by: Yu Chao <chao2...@samsung.com>
> ---
>  fs/f2fs/segment.h |   13 +++++++++++++
>  1 file changed, 13 insertions(+)
> 
> diff --git a/fs/f2fs/segment.h b/fs/f2fs/segment.h
> index 7f94d78..d43ab9f 100644
> --- a/fs/f2fs/segment.h
> +++ b/fs/f2fs/segment.h
> @@ -543,6 +543,7 @@ static inline void check_block_count(struct f2fs_sb_info
> *sbi,
>  {
>       struct f2fs_sm_info *sm_info = SM_I(sbi);
>       unsigned int end_segno = sm_info->segment_count - 1;
> +     int *valid_map = (int *)raw_sit->valid_map;
>       int valid_blocks = 0;
>       int i;
>  
> @@ -552,6 +553,19 @@ static inline void check_block_count(struct
> f2fs_sb_info *sbi,
>       /* check boundary of a given segment number */
>       BUG_ON(segno > end_segno);
>  
> +     /* check all ones or zeros valid_map */
> +     if (GET_SIT_VBLOCKS(raw_sit) == 0) {
> +             for (i = 0; i < SIT_VBLOCK_MAP_SIZE / sizeof(int); i++)

We cannot guarantee all the time that SIT_VBLOCK_MAP_SIZE is multiple of
sizeof(int).
How about using memcmp() with __u8?

> +                     if (unlikely(valid_map[i] != 0))
> +                             BUG();
> +             return;
> +     } else if (GET_SIT_VBLOCKS(raw_sit) == sbi->blocks_per_seg) {
> +             for (i = 0; i < SIT_VBLOCK_MAP_SIZE / sizeof(int); i++)
> +                     if (unlikely(valid_map[i] != -1))
> +                             BUG();
> +             return;
> +     }
> +
>       /* check bitmap with valid block count */
>       for (i = 0; i < sbi->blocks_per_seg; i++)
>               if (f2fs_test_bit(i, raw_sit->valid_map))
> ---
> 
> --
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-- 
Jaegeuk Kim
Samsung


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