diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index 8e4a7cdbc9f560d217d0427fa8a2836bed3016f5..1aa91d57404ad6354357b1f421274a31012c48c6 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -4545,8 +4545,11 @@ int extent_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
 			offset_in_extent = em_start - em->start;
 		em_end = extent_map_end(em);
 		em_len = em_end - em_start;
-		disko = em->block_start + offset_in_extent;
 		flags = 0;
+		if (em->block_start < EXTENT_MAP_LAST_BYTE)
+			disko = em->block_start + offset_in_extent;
+		else
+			disko = 0;
 
 		/*
 		 * bump off for our next call to get_extent