Hi Chao,

On Sun, Sep 18, 2016 at 11:30:05PM +0800, Chao Yu wrote:
> From: Chao Yu <yuch...@huawei.com>
> 
> Making updating of sbi flag atomic by using {test,set,clear}_bit,
> otherwise in concurrency scenario, the flag could be updated incorrectly.
> 
> Signed-off-by: Chao Yu <yuch...@huawei.com>
> ---
>  fs/f2fs/f2fs.h | 10 ++++++----
>  1 file changed, 6 insertions(+), 4 deletions(-)
> 
> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
> index 9b4bbf2..c30f744b 100644
> --- a/fs/f2fs/f2fs.h
> +++ b/fs/f2fs/f2fs.h
> @@ -794,7 +794,7 @@ struct f2fs_sb_info {
>       struct proc_dir_entry *s_proc;          /* proc entry */
>       struct f2fs_super_block *raw_super;     /* raw super block pointer */
>       int valid_super_block;                  /* valid super block no */
> -     int s_flag;                             /* flags for sbi */
> +     unsigned long s_flag;                           /* flags for sbi */
>  
>  #ifdef CONFIG_F2FS_FS_ENCRYPTION
>       u8 key_prefix[F2FS_KEY_DESC_PREFIX_SIZE];
> @@ -1063,17 +1063,19 @@ static inline struct address_space 
> *NODE_MAPPING(struct f2fs_sb_info *sbi)
>  
>  static inline bool is_sbi_flag_set(struct f2fs_sb_info *sbi, unsigned int 
> type)
>  {
> -     return sbi->s_flag & (0x01 << type);
> +     return test_bit(type, &sbi->s_flag);
>  }
>  
>  static inline void set_sbi_flag(struct f2fs_sb_info *sbi, unsigned int type)
>  {
> -     sbi->s_flag |= (0x01 << type);
> +     if (!test_bit(type, &sbi->s_flag))
> +             set_bit(type, &sbi->s_flag);

The set_bit() is enough, no?

>  }
>  
>  static inline void clear_sbi_flag(struct f2fs_sb_info *sbi, unsigned int 
> type)
>  {
> -     sbi->s_flag &= ~(0x01 << type);
> +     if (test_bit(type, &sbi->s_flag))
> +             clear_bit(type, &sbi->s_flag);

ditto.

Thanks,

>  }
>  
>  static inline unsigned long long cur_cp_version(struct f2fs_checkpoint *cp)
> -- 
> 2.7.2

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