diff --git a/fs/nfs/internal.h b/fs/nfs/internal.h
index 2ecd38e1d17a..ffd382aa31ac 100644
--- a/fs/nfs/internal.h
+++ b/fs/nfs/internal.h
@@ -13,7 +13,7 @@
 #include <linux/nfslocalio.h>
 #include <linux/wait_bit.h>
 
-#define NFS_SB_MASK (SB_NOSUID|SB_NODEV|SB_NOEXEC|SB_SYNCHRONOUS)
+#define NFS_SB_MASK (SB_RDONLY|SB_NOSUID|SB_NODEV|SB_NOEXEC|SB_SYNCHRONOUS)
 
 extern const struct export_operations nfs_export_ops;