xen/ioemu-7615-qcow2-fix-alloc_cluster_link_l2.patch

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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>
Index: xen-4.0.2-testing/tools/ioemu-qemu-xen/block-qcow2.c
===================================================================
--- xen-4.0.2-testing.orig/tools/ioemu-qemu-xen/block-qcow2.c
+++ xen-4.0.2-testing/tools/ioemu-qemu-xen/block-qcow2.c
@@ -916,7 +916,7 @@ static int alloc_cluster_link_l2(BlockDr
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]) & ~QCOW_OFLAG_COPIED, 1);
ret = 0;
err: