Btrfs: Fix nodatacow for the new data=ordered mode

Signed-off-by: Chris Mason <chris.mason@oracle.com>
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 3932c7c..59b64c7 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -36,6 +36,7 @@
 #include <linux/bit_spinlock.h>
 #include <linux/version.h>
 #include <linux/xattr.h>
+#include <linux/vmalloc.h>
 #include "ctree.h"
 #include "disk-io.h"
 #include "transaction.h"