passthrough_ll: document that functionality is restricted

diff --git a/example/passthrough_ll.c b/example/passthrough_ll.c
index b31160eb6ed6e4a16bf72a43979b139530776304..ac566ad16bfcd1022fe569bb795c9648da0f7edc 100644 (file)
--- a/example/passthrough_ll.c
+++ b/example/passthrough_ll.c
@@ -13,7 +13,11 @@
  * just "passing through" all requests to the corresponding user-space
  * libc functions. In contrast to passthrough.c and passthrough_fh.c,
  * this implementation ises the low-level API. Its performance should
- * be the least bad among the three.
+ * be the least bad among the three, but many operations are not
+ * implemented. In particular, it is not possible to remove files (or
+ * directories) because the code necessary to defer actual removal
+ * until the file is not opened anymore would make the example much
+ * more complicated.
  *
  * Compile with:
  *