diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index ca7e5d4..26826a5 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -236,7 +236,7 @@
 					   end_pos - start_pos, p, 0);
 		BUG_ON(err);
 		em->start = start_pos;
-		em->end = end_pos;
+		em->end = end_pos - 1;
 		em->block_start = EXTENT_MAP_INLINE;
 		em->block_end = EXTENT_MAP_INLINE;
 		add_extent_mapping(em_tree, em);