cachefiles: Don't shorten if over 1G

fs/cachefiles/content-map.c

diff --git a/fs/cachefiles/content-map.c b/fs/cachefiles/content-map.c
index 0d3ee4c..e820b017 100644
--- a/fs/cachefiles/content-map.c
+++ b/fs/cachefiles/content-map.c
@@ -360,7 +360,8 @@ void cachefiles_shorten_content_map(struct cachefiles_object *object,
 
 	write_lock_bh(&object->content_map_lock);
 
-	if (object->content_info == CACHEFILES_CONTENT_MAP) {
+	if (object->content_info == CACHEFILES_CONTENT_MAP &&
+	    new_size <= CACHEFILES_SIZE_LIMIT) {
 		if (cookie->zero_point > new_size)
 			cookie->zero_point = new_size;