progs: Add BTRFS_IOC_NODATACOW ioctl to progs

Index: btrfs-progs-unstable/ioctl.h
===================================================================
@@ -58,4 +58,6 @@ struct btrfs_ioctl_vol_args {
 				   struct btrfs_ioctl_vol_args)
 #define BTRFS_IOC_COMPRESS _IOW(BTRFS_IOCTL_MAGIC, 15, \
 			   struct btrfs_ioctl_vol_args)
+#define BTRFS_IOC_NODATACOW _IOW(BTRFS_IOCTL_MAGIC, 16, \
+			   struct btrfs_ioctl_vol_args)
 #endif

Index: btrfs-progs-unstable/btrfsctl.c
===================================================================
@@ -56,6 +56,7 @@ static void print_usage(void)
 	printf("\t-a: scans all devices for Btrfs filesystems\n");
 	printf("\t-c: forces a single FS sync\n");
 	printf("\t--compress filename: sets compress flag on the file\n");
+	printf("\t--nodatacow filename: sets nodatacow flag on the file\n");
 	printf("%s\n", BTRFS_BUILD_VERSION);
 	exit(1);
 }

@@ -185,6 +186,12 @@ int main(int ac, char **av)
 				print_usage();
 			}
 			command = BTRFS_IOC_COMPRESS;
+		} else if (strcmp(av[i], "--nodatacow") == 0) {
+			if (i >= ac - 1) {
+				fprintf(stderr, "-r requires an arg\n");
+				print_usage();
+			}
+			command = BTRFS_IOC_NODATACOW;
 		}
 	}
 	if (command == 0) {