From f4388dd338424913b029a37bf75675afba67b6e2 Mon Sep 17 00:00:00 2001
From: Kevin Wolf <kwolf@redhat.com>
Date: Thu, 29 Apr 2010 14:25:58 -0300
Subject: [PATCH 1/2] qemu-img rebase: Fix output image corruption

RH-Author: Kevin Wolf <kwolf@redhat.com>
Message-id: <1272551158-16200-1-git-send-email-kwolf@redhat.com>
Patchwork-id: 8898
O-Subject: [RHEL-5.6/5.5.z KVM PATCH] qemu-img rebase: Fix output image
	corruption
Bugzilla: 587278
RH-Acked-by: Naphtali Sprei <nsprei@redhat.com>
RH-Acked-by: Christoph Hellwig <chellwig@redhat.com>
RH-Acked-by: Juan Quintela <quintela@redhat.com>

Bugzilla: 587278
Upstream status: Submitted

qemu-img rebase must always give clusters in the COW file priority over those
in the backing file. As it failed to use number of non-allocated clusters but
assumed the maximum, it was possible that allocated clusters were taken from
the backing file instead, leading to a corrupted output image.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
 qemu/qemu-img.c |    6 +++---
 1 files changed, 3 insertions(+), 3 deletions(-)

Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
---
 qemu/qemu-img.c |    6 +++---
 1 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/qemu/qemu-img.c b/qemu/qemu-img.c
index 5c8351c..2b9c3ad 100644
--- a/qemu/qemu-img.c
+++ b/qemu/qemu-img.c
@@ -1111,7 +1111,7 @@ static int img_rebase(int argc, char **argv)
     if (!unsafe) {
         uint64_t num_sectors;
         uint64_t sector;
-        int n, n1;
+        int n;
         uint8_t buf_old[IO_BUF_SIZE];
         uint8_t buf_new[IO_BUF_SIZE];
 
@@ -1127,8 +1127,8 @@ static int img_rebase(int argc, char **argv)
             }
 
             /* If the cluster is allocated, we don't need to take action */
-            if (bdrv_is_allocated(bs, sector, n, &n1)) {
-                n = n1;
+            ret = bdrv_is_allocated(bs, sector, n, &n);
+            if (ret) {
                 continue;
             }
 
-- 
1.7.0.3