Btrfs: fix extent boundary check in bio_readpage_error

Signed-off-by: NFilipe David Borba Manana <fdmanana@gmail.com>
Signed-off-by: NJosef Bacik <jbacik@fb.com>
Signed-off-by: NChris Mason <clm@fb.com>

fs/btrfs/extent_io.c

@@ -2156,7 +2156,7 @@ static int bio_readpage_error(struct bio *failed_bio, u64 phy_offset,
 			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;
 		}