From: Alex Rousskov <rousskov@measurement-factory.com>
Date: Sun, 20 Jan 2013 17:31:50 +0000 (-0700)
Subject: Do not allow broken IpcIo-based cache_dir to be selected for swap out.
X-Git-Tag: SQUID_3_5_0_1~444^2~73
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=7e2d5ef6486a33fc80e9b09017452611eab43da0;p=thirdparty%2Fsquid.git

Do not allow broken IpcIo-based cache_dir to be selected for swap out.

I/O code refuses to read or write when file error is set, but canRead()
and canWrite() ignored that fact, allowing broken files to be selected for
writing (at least). SwapDir::createStoreIO() would then return nil, leading
to missed swapout opportunities (if other cache_dirs could write) and wasted
CPU cycles.
---

diff --git a/src/DiskIO/IpcIo/IpcIoFile.cc b/src/DiskIO/IpcIo/IpcIoFile.cc
index 83d8f13f86..52ea41136d 100644
--- a/src/DiskIO/IpcIo/IpcIoFile.cc
+++ b/src/DiskIO/IpcIo/IpcIoFile.cc
@@ -184,13 +184,13 @@ IpcIoFile::close()
 bool
 IpcIoFile::canRead() const
 {
-    return diskId >= 0 && canWait();
+    return diskId >= 0 && !error_ && canWait();
 }
 
 bool
 IpcIoFile::canWrite() const
 {
-    return diskId >= 0 && canWait();
+    return diskId >= 0 && !error_ && canWait();
 }
 
 bool