- * fill_textconv is not remotely thread-safe; it may load objects
- * behind the scenes, and it modifies the global diff tempfile
- * structure.
+ * fill_textconv is not remotely thread-safe; it modifies the global
+ * diff tempfile structure, writes to the_repo's odb and might
+ * internally call thread-unsafe functions such as the
+ * prepare_packed_git() lazy-initializator. Because of the last two, we
+ * must ensure mutual exclusion between this call and the object reading
+ * API, thus we use obj_read_lock() here.
+ *
+ * TODO: allowing text conversion to run in parallel with object
+ * reading operations might increase performance in the multithreaded
+ * non-worktreee git-grep with --textconv.