extern int posix_lock_file(struct file *, struct file_lock *);
extern int posix_lock_file_wait(struct file *, struct file_lock *);
extern void posix_block_lock(struct file_lock *, struct file_lock *);
-extern void posix_unblock_lock(struct file *, struct file_lock *);
+extern int posix_unblock_lock(struct file *, struct file_lock *);
extern int posix_locks_deadlock(struct file_lock *, struct file_lock *);
extern int flock_lock_file_wait(struct file *filp, struct file_lock *fl);
extern int __break_lease(struct inode *inode, unsigned int flags);