From: Kevin Wolf To: qemu-devel@nongnu.org Subject: [Qemu-devel] [PATCH] qcow2 corruption: Fix alloc_cluster_link_l2 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 < --- block-qcow2.c | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-) diff -up qemu-kvm-0.10/qemu/block-qcow2.c.qcow2-corruption qemu-kvm-0.10/qemu/block-qcow2.c --- qemu-kvm-0.10/qemu/block-qcow2.c.qcow2-corruption 2009-04-20 14:41:22.000000000 +0100 +++ qemu-kvm-0.10/qemu/block-qcow2.c 2009-04-20 14:41:54.000000000 +0100 @@ -912,7 +912,7 @@ 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]), 1); ret = 0; err: