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From 2f67e26a87ace81cb7a9c122c39f4d8d667d69d1 Mon Sep 17 00:00:00 2001
From: Max Reitz <mreitz@redhat.com>
Date: Sat, 13 Jun 2015 16:22:19 +0200
Subject: [PATCH 25/42] qcow2: Reuse refcount table in calculate_refcounts()
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Message-id: <1434212556-3927-26-git-send-email-mreitz@redhat.com>
Patchwork-id: 66044
O-Subject: [RHEL-7.2 qemu-kvm PATCH 25/42] qcow2: Reuse refcount table in calculate_refcounts()
Bugzilla: 1129893
RH-Acked-by: Jeffrey Cody <jcody@redhat.com>
RH-Acked-by: Fam Zheng <famz@redhat.com>
RH-Acked-by: Stefan Hajnoczi <stefanha@redhat.com>

BZ: 1129893

We will later call calculate_refcounts multiple times, so reuse the
refcount table if possible.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: BenoƮt Canet <benoit.canet@nodalink.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
(cherry picked from commit 9696df219a71c6608f058ade8873d6d0b4e352fe)

Signed-off-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
---
 block/qcow2-refcount.c | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/block/qcow2-refcount.c b/block/qcow2-refcount.c
index 7d03e65..8f1215c 100644
--- a/block/qcow2-refcount.c
+++ b/block/qcow2-refcount.c
@@ -1631,10 +1631,12 @@ static int calculate_refcounts(BlockDriverState *bs, BdrvCheckResult *res,
     QCowSnapshot *sn;
     int ret;
 
-    *refcount_table = g_try_new0(uint16_t, *nb_clusters);
-    if (*nb_clusters && *refcount_table == NULL) {
-        res->check_errors++;
-        return -ENOMEM;
+    if (!*refcount_table) {
+        *refcount_table = g_try_new0(uint16_t, *nb_clusters);
+        if (*nb_clusters && *refcount_table == NULL) {
+            res->check_errors++;
+            return -ENOMEM;
+        }
     }
 
     /* header */
@@ -1750,7 +1752,7 @@ int qcow2_check_refcounts(BlockDriverState *bs, BdrvCheckResult *res,
 {
     BDRVQcowState *s = bs->opaque;
     int64_t size, highest_cluster, nb_clusters;
-    uint16_t *refcount_table;
+    uint16_t *refcount_table = NULL;
     int ret;
 
     size = bdrv_getlength(bs->file);
-- 
1.8.3.1