[Qemu-devel] [7165] qcow2 corruption: Fix alloc_cluster_link_l2 (Kevin Wolf)

[Qemu-devel] [7165] qcow2 corruption: Fix alloc_cluster_link_l2 (Kevin Wolf)

[Anthony Liguori]

Revision: 7165
          http://svn.sv.gnu.org/viewvc/?view=rev&root=qemu&revision=7165
Author:   aliguori
Date:     2009-04-17 20:44:06 +0000 (Fri, 17 Apr 2009)
Log Message:
-----------
qcow2 corruption: Fix alloc_cluster_link_l2 (Kevin Wolf)

This patch fixes a qcow2 corruption bug introduced in SVN Rev 5861. L2 tables
are big endian, so entries must be converted before being passed to functions.

This bug is easy to trigger. The following script will create and destroy a
qcow2 image (the header is gone after three loop iterations):

    #!/bin/bash
    qemu-img create -f qcow2 test.qcow 1M
    for i in $(seq 1 10); do
    qemu-system-x86_64 -hda test.qcow -monitor stdio > /dev/null 2>&1 <<EOF
    savevm test-$i
    quit
    EOF
    done

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>

Revision Links:
--------------
    http://svn.sv.gnu.org/viewvc/?view=rev&root=qemu&revision=5861

Modified Paths:
--------------
    trunk/block-qcow2.c

Modified: trunk/block-qcow2.c
===================================================================
--- trunk/block-qcow2.c	2009-04-17 20:01:12 UTC (rev 7164)
+++ trunk/block-qcow2.c	2009-04-17 20:44:06 UTC (rev 7165)
@@ -1007,7 +1007,7 @@
         goto err;
 
     for (i = 0; i < j; i++)
-        free_any_clusters(bs, old_cluster[i], 1);
+        free_any_clusters(bs, be64_to_cpu(old_cluster[i]), 1);
 
     ret = 0;
 err: