Btrfs: fix extent boundary check in bio_readpage_error

Signed-off-by: Filipe David Borba Manana <fdmanana@gmail.com>
Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Chris Mason <clm@fb.com>
diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index d97250a..3721820 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -2156,7 +2156,7 @@
 			return -EIO;
 		}
 
-		if (em->start > start || em->start + em->len < start) {
+		if (em->start > start || em->start + em->len <= start) {
 			free_extent_map(em);
 			em = NULL;
 		}