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From 3a454be93c4750bad515dc3dacc83a3feff5e02c Mon Sep 17 00:00:00 2001
From: Max Reitz <mreitz@redhat.com>
Date: Tue, 7 Jan 2014 21:57:10 +0100
Subject: [PATCH 05/14] qcow2-cache: Empty cache

RH-Author: Max Reitz <mreitz@redhat.com>
Message-id: <1389131839-12920-6-git-send-email-mreitz@redhat.com>
Patchwork-id: 56541
O-Subject: [RHEL-7.0 qemu-kvm PATCH v2 05/14] qcow2-cache: Empty cache
Bugzilla: 1033490
RH-Acked-by: Kevin Wolf <kwolf@redhat.com>
RH-Acked-by: Fam Zheng <famz@redhat.com>
RH-Acked-by: Stefan Hajnoczi <stefanha@redhat.com>

BZ: 1033490

Add a function for emptying a cache, i.e., flushing it and marking all
elements invalid.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
(cherry picked from commit e7108feaace8e02b3a4bf010448fc2744f753381)

Signed-off-by: Max Reitz <mreitz@redhat.com>
---
 block/qcow2-cache.c | 18 ++++++++++++++++++
 block/qcow2.h       |  2 ++
 2 files changed, 20 insertions(+)

Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
---
 block/qcow2-cache.c |   18 ++++++++++++++++++
 block/qcow2.h       |    2 ++
 2 files changed, 20 insertions(+), 0 deletions(-)

diff --git a/block/qcow2-cache.c b/block/qcow2-cache.c
index eb1d69b..8ecbb5b 100644
--- a/block/qcow2-cache.c
+++ b/block/qcow2-cache.c
@@ -200,6 +200,24 @@ void qcow2_cache_depends_on_flush(Qcow2Cache *c)
     c->depends_on_flush = true;
 }
 
+int qcow2_cache_empty(BlockDriverState *bs, Qcow2Cache *c)
+{
+    int ret, i;
+
+    ret = qcow2_cache_flush(bs, c);
+    if (ret < 0) {
+        return ret;
+    }
+
+    for (i = 0; i < c->size; i++) {
+        assert(c->entries[i].ref == 0);
+        c->entries[i].offset = 0;
+        c->entries[i].cache_hits = 0;
+    }
+
+    return 0;
+}
+
 static int qcow2_cache_find_entry_to_replace(Qcow2Cache *c)
 {
     int i;
diff --git a/block/qcow2.h b/block/qcow2.h
index e4c140c..5ca6b78 100644
--- a/block/qcow2.h
+++ b/block/qcow2.h
@@ -489,6 +489,8 @@ int qcow2_cache_set_dependency(BlockDriverState *bs, Qcow2Cache *c,
     Qcow2Cache *dependency);
 void qcow2_cache_depends_on_flush(Qcow2Cache *c);
 
+int qcow2_cache_empty(BlockDriverState *bs, Qcow2Cache *c);
+
 int qcow2_cache_get(BlockDriverState *bs, Qcow2Cache *c, uint64_t offset,
     void **table);
 int qcow2_cache_get_empty(BlockDriverState *bs, Qcow2Cache *c, uint64_t offset,
-- 
1.7.1