From 91663b86af6df6bb44a0fc3481e1c0f6e524679f Mon Sep 17 00:00:00 2001
From: Francesco Chemolli <kinkie@squid-cache.org>
Date: Thu, 9 Jul 2015 15:50:22 +0200
Subject: [PATCH] Check invariant in DiskdFile::readDone (CID 980997)

---
 src/DiskIO/DiskDaemon/DiskdFile.cc | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/src/DiskIO/DiskDaemon/DiskdFile.cc b/src/DiskIO/DiskDaemon/DiskdFile.cc
index 3d115a0adc..a257012a27 100644
--- a/src/DiskIO/DiskDaemon/DiskdFile.cc
+++ b/src/DiskIO/DiskDaemon/DiskdFile.cc
@@ -348,8 +348,11 @@ DiskdFile::readDone(diomsg * M)
     ReadRequest::Pointer readRequest = dynamic_cast<ReadRequest *>(M->requestor);
 
     /* remove the free protection */
-    if (readRequest != NULL)
-        readRequest->unlock();
+    if (readRequest != NULL) {
+        const uint32_t lcount = readRequest->unlock();
+        if (lcount == 0)
+            debugs(79, DBG_IMPORTANT, "invariant check failed: redRequest reference count is 0");
+    }
 
     if (M->status < 0) {
         ++diskd_stats.read.fail;
-- 
2.47.3