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Subject[PATCH 3/6] f2fs: fix to avoid race condition when updating sbi flag
Date
From: Chao Yu <yuchao0@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 <yuchao0@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
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