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From f9b42568a13151521cb8edf38f567e8c5cf25396 Mon Sep 17 00:00:00 2001
From: Max Reitz <mreitz@redhat.com>
Date: Mon, 4 Nov 2013 22:32:23 +0100
Subject: [PATCH 30/87] qcow2: Correct snapshots size for overlap check

RH-Author: Max Reitz <mreitz@redhat.com>
Message-id: <1383604354-12743-33-git-send-email-mreitz@redhat.com>
Patchwork-id: 55332
O-Subject: [RHEL-7.0 qemu-kvm PATCH 32/43] qcow2: Correct snapshots size for overlap check
Bugzilla: 1004347
RH-Acked-by: Kevin Wolf <kwolf@redhat.com>
RH-Acked-by: Laszlo Ersek <lersek@redhat.com>
RH-Acked-by: Fam Zheng <famz@redhat.com>
RH-Acked-by: Stefan Hajnoczi <stefanha@redhat.com>

BZ: 1004347

Using s->snapshots_size instead of snapshots_size for the metadata
overlap check in qcow2_write_snapshots leads to the detection of an
overlap with the main qcow2 image header when deleting the last
snapshot, since s->snapshots_size has not yet been updated and is
therefore non-zero. However, the offset returned by qcow2_alloc_clusters
will be zero since snapshots_size is zero. Therefore, an overlap is
detected albeit no such will occur.

This patch fixes this by replacing s->snapshots_size by snapshots_size
when calling qcow2_pre_write_overlap_check.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
(cherry picked from commit 0f39ac9a07cc10278e37d87076b143008f28aa3b)

Signed-off-by: Max Reitz <mreitz@redhat.com>
---
 block/qcow2-snapshot.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
---
 block/qcow2-snapshot.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/block/qcow2-snapshot.c b/block/qcow2-snapshot.c
index e7e6013..450e4f5 100644
--- a/block/qcow2-snapshot.c
+++ b/block/qcow2-snapshot.c
@@ -192,7 +192,7 @@ static int qcow2_write_snapshots(BlockDriverState *bs)
     /* The snapshot list position has not yet been updated, so these clusters
      * must indeed be completely free */
     ret = qcow2_pre_write_overlap_check(bs, QCOW2_OL_DEFAULT, offset,
-                                        s->snapshots_size);
+                                        snapshots_size);
     if (ret < 0) {
         return ret;
     }
-- 
1.7.1