From 72d95a4563149dfda0502ef28f06c7f7f972bd75 Mon Sep 17 00:00:00 2001
From: "Richard W.M. Jones" <rjones@redhat.com>
Date: Tue, 1 Apr 2025 16:51:24 +0100
Subject: [PATCH] file: Document implicit assumption about eviction windows

Add a comment that slots in the window list are only valid when len > 0.
This was true before but only implicit.

(cherry picked from commit 2022ac667f3c1de81b692f0128dd83a7c4999e38)
---
 plugins/file/file.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/plugins/file/file.c b/plugins/file/file.c
index d1e91203..b8470c20 100644
--- a/plugins/file/file.c
+++ b/plugins/file/file.c
@@ -112,7 +112,7 @@ static enum { cache_default, cache_none } cache_mode = cache_default;
 struct write_window {
   int fd;
   uint64_t offset;
-  size_t len;
+  size_t len;           /* window slot only valid if len > 0 */
 };
 
 static pthread_mutex_t window_lock = PTHREAD_MUTEX_INITIALIZER;
-- 
2.47.1