fat: add fat_msg_ratelimit()

Add a fat_msg_ratelimit() to limit the message generation rate.
Signed-off-by: Namjae Jeon <linkinjeon@gmail.com>
Signed-off-by: Amit Sahrawat <amit.sahrawat83@gmail.com>
Acked-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fs/fat/fat.h

@@ -335,6 +335,11 @@ void __fat_fs_error(struct super_block *sb, int report, const char *fmt, ...);
 	__fat_fs_error(sb, __ratelimit(&MSDOS_SB(sb)->ratelimit), fmt , ## args)
 __printf(3, 4) __cold
 void fat_msg(struct super_block *sb, const char *level, const char *fmt, ...);
+#define fat_msg_ratelimit(sb, level, fmt, args...)	\
+	do {	\
+			if (__ratelimit(&MSDOS_SB(sb)->ratelimit))	\
+				fat_msg(sb, level, fmt, ## args);	\
+	 } while (0)
 extern int fat_clusters_flush(struct super_block *sb);
 extern int fat_chain_add(struct inode *inode, int new_dclus, int nr_cluster);
 extern void fat_time_fat2unix(struct msdos_sb_info *sbi, struct timespec *ts,