-#define DISK_CONDITIONER_IOC_GET _IOR('A', 18, disk_conditioner_info)
-#define DISK_CONDITIONER_FSCTL_GET IOCBASECMD(DISK_CONDITIONER_IOC_GET)
-#define DISK_CONDITIONER_IOC_SET _IOW('A', 19, disk_conditioner_info)
-#define DISK_CONDITIONER_FSCTL_SET IOCBASECMD(DISK_CONDITIONER_IOC_SET)
+#define DISK_CONDITIONER_IOC_GET _IOR('A', 18, disk_conditioner_info)
+#define DISK_CONDITIONER_FSCTL_GET IOCBASECMD(DISK_CONDITIONER_IOC_GET)
+#define DISK_CONDITIONER_IOC_SET _IOW('A', 19, disk_conditioner_info)
+#define DISK_CONDITIONER_FSCTL_SET IOCBASECMD(DISK_CONDITIONER_IOC_SET)
+
+/* Check if a file is only open once (pass zero for the extra arg) */
+#define FSIOC_FD_ONLY_OPEN_ONCE _IOWR('A', 21, uint32_t)