f2fs: fix to avoid race condition when updating sbi flag

chaseyu · Jaegeuk Kim · commit fadb2fb8af53 · 2016-09-30T10:05:50.000-07:00
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 &lt;yuchao0@huawei.com&gt;
Signed-off-by: Jaegeuk Kim &lt;jaegeuk@kernel.org&gt;
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
@@ -777,7 +777,7 @@ 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];
@@ -1046,17 +1046,17 @@ 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);
+	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);
+	clear_bit(type, &sbi->s_flag);
 }
 
 static inline unsigned long long cur_cp_version(struct f2fs_checkpoint *cp)

Original file line number	Diff line number	Diff line change
`@@ -777,7 +777,7 @@ struct f2fs_sb_info {`
`777`	`777`	`struct proc_dir_entry s_proc; / proc entry */`
`778`	`778`	`struct f2fs_super_block raw_super; / raw super block pointer */`
`779`	`779`	`int valid_super_block; /* valid super block no */`
`780`		`- int s_flag; /* flags for sbi */`
	`780`	`+ unsigned long s_flag; /* flags for sbi */`
`781`	`781`
`782`	`782`	`#ifdef CONFIG_F2FS_FS_ENCRYPTION`
`783`	`783`	`u8 key_prefix[F2FS_KEY_DESC_PREFIX_SIZE];`
`@@ -1046,17 +1046,17 @@ static inline struct address_space NODE_MAPPING(struct f2fs_sb_info sbi)`
`1046`	`1046`
`1047`	`1047`	`static inline bool is_sbi_flag_set(struct f2fs_sb_info *sbi, unsigned int type)`
`1048`	`1048`	`{`
`1049`		`- return sbi->s_flag & (0x01 << type);`
	`1049`	`+ return test_bit(type, &sbi->s_flag);`
`1050`	`1050`	`}`
`1051`	`1051`
`1052`	`1052`	`static inline void set_sbi_flag(struct f2fs_sb_info *sbi, unsigned int type)`
`1053`	`1053`	`{`
`1054`		`- sbi->s_flag \|= (0x01 << type);`
	`1054`	`+ set_bit(type, &sbi->s_flag);`
`1055`	`1055`	`}`
`1056`	`1056`
`1057`	`1057`	`static inline void clear_sbi_flag(struct f2fs_sb_info *sbi, unsigned int type)`
`1058`	`1058`	`{`
`1059`		`- sbi->s_flag &= ~(0x01 << type);`
	`1059`	`+ clear_bit(type, &sbi->s_flag);`
`1060`	`1060`	`}`
`1061`	`1061`
`1062`	`1062`	`static inline unsigned long long cur_cp_version(struct f2fs_checkpoint *cp)`