diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index e274e9c..e7e5b3d 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -2178,6 +2178,9 @@
  *
  * @handle - handle for journal operations
  * @mpd - extent to map
+ * @give_up_on_write - we set this to true iff there is a fatal error and there
+ *                     is no hope of writing the data. The caller should discard
+ *                     dirty pages to avoid infinite loops.
  *
  * The function maps extent starting at mpd->lblk of length mpd->len. If it is
  * delayed, blocks are allocated, if it is unwritten, we may need to convert