diff --git a/btrfsctl.c b/btrfsctl.c
index e90c6fc5..7e7e79b5 100644
--- a/btrfsctl.c
+++ b/btrfsctl.c
@@ -51,6 +51,7 @@ void print_usage(void)
 	printf("\t-r [+-]size[gkm] resize the FS\n");
 	printf("\t-A device scans the device for a Btrfs filesystem\n");
 	printf("\t-a scans all devices for Btrfs filesystems\n");
+	printf("\t-c forces a single FS sync\n");
 	exit(1);
 }
 
@@ -115,6 +116,8 @@ int main(int ac, char **av)
 				exit(1);
 			}
 			command = BTRFS_IOC_RESIZE;
+		} else if (strcmp(av[i], "-c") == 0) {
+			command = BTRFS_IOC_SYNC;
 		}
 	}
 	if (command == 0) {
diff --git a/ioctl.h b/ioctl.h
index b0e73f51..85ed35a7 100644
--- a/ioctl.h
+++ b/ioctl.h
@@ -36,6 +36,14 @@ struct btrfs_ioctl_vol_args {
 				   struct btrfs_ioctl_vol_args)
 #define BTRFS_IOC_SCAN_DEV _IOW(BTRFS_IOCTL_MAGIC, 4, \
 				   struct btrfs_ioctl_vol_args)
+/* trans start and trans end are dangerous, and only for
+ * use by applications that know how to avoid the
+ * resulting deadlocks
+ */
+#define BTRFS_IOC_TRANS_START  _IO(BTRFS_IOCTL_MAGIC, 6)
+#define BTRFS_IOC_TRANS_END    _IO(BTRFS_IOCTL_MAGIC, 7)
+#define BTRFS_IOC_SYNC         _IO(BTRFS_IOCTL_MAGIC, 8)
+
 #define BTRFS_IOC_CLONE        _IOW(BTRFS_IOCTL_MAGIC, 9, int)
 #define BTRFS_IOC_ADD_DEV _IOW(BTRFS_IOCTL_MAGIC, 10, \
 				   struct btrfs_ioctl_vol_args)
@@ -43,4 +51,5 @@ struct btrfs_ioctl_vol_args {
 				   struct btrfs_ioctl_vol_args)
 #define BTRFS_IOC_BALANCE _IOW(BTRFS_IOCTL_MAGIC, 12, \
 				   struct btrfs_ioctl_vol_args)
+
 #endif