extern int __sync_blockdev(struct block_device *bdev, int wait);
void iterate_bdevs(void (*)(struct block_device *, void *), void *);
void emergency_thaw_bdev(struct super_block *sb);
extern int __sync_blockdev(struct block_device *bdev, int wait);
void iterate_bdevs(void (*)(struct block_device *, void *), void *);
void emergency_thaw_bdev(struct super_block *sb);
*/
extern int reconfigure_super(struct fs_context *);
extern bool trylock_super(struct super_block *sb);
*/
extern int reconfigure_super(struct fs_context *);
extern bool trylock_super(struct super_block *sb);