[PATCH 3/6] f2fs: fix to avoid race condition when updating sbi flag

[Chao Yu]

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