From 188c4737c54787bbd734c628121f7f0e4f833cd1 Mon Sep 17 00:00:00 2001
From: Richard Jones <rjones@redhat.com>
Date: Thu, 11 Jun 2015 11:40:18 +0200
Subject: [PATCH 18/30] curl: Fix hang reading from slow connections

Message-id: <1434022828-13037-12-git-send-email-rjones@redhat.com>
Patchwork-id: 65847
O-Subject: [RHEL-7.2 qemu-kvm v3 PATCH 11/21] curl: Fix hang reading from slow connections
Bugzilla: 1226684
RH-Acked-by: Miroslav Rezanina <mrezanin@redhat.com>
RH-Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
RH-Acked-by: Laszlo Ersek <lersek@redhat.com>

From: Matthew Booth <mbooth@redhat.com>

When receiving a new aio read request, we first look for an existing
transaction whose range will cover the read request by the time it
completes. However, we weren't checking that the existing transaction
was still active. If it had timed out, we were adding the request to a
transaction which would never complete and had already been cancelled,
resulting in a hang.

Signed-off-by: Matthew Booth <mbooth@redhat.com>
Tested-by: Richard W.M. Jones <rjones@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

Upstream-status: b7079df4100069959f4e9d90d5cb5ba7d4ebbf1a
Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
---
 block/curl.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/block/curl.c b/block/curl.c
index 41cf015..1bff71a 100644
--- a/block/curl.c
+++ b/block/curl.c
@@ -220,7 +220,8 @@ static int curl_find_buf(BDRVCURLState *s, size_t start, size_t len,
         }
 
         // Wait for unfinished chunks
-        if ((start >= state->buf_start) &&
+        if (state->in_use &&
+            (start >= state->buf_start) &&
             (start <= buf_fend) &&
             (end >= state->buf_start) &&
             (end <= buf_fend))
-- 
1.8.3.1