When creating a snapshots, the refcount adjustment function basically adjusted the refcounts of any cluster with a non-zero L2 entry. However, the L2 entry of unallocated zero clusters is exactly one (therefore non-zero) which led to wrong refcount updates on cluster 0 (the main qcow2 header), since the cluster index for these unallocated zero clusters is 0.
This series fixes this by taking all cluster types specifically into account using qcow2_get_cluster_type and handling them accordingly. Furthermore, a short test is added. v2: - more thorough commit message - take pre-allocated zero clusters into account - abort on unknown cluster type - a test case Max Reitz (2): qcow2-refcount: Snapshot update for zero clusters qemu-iotests: Snapshotting zero clusters block/qcow2-refcount.c | 52 ++++++++++++++++++++++++++------------- tests/qemu-iotests/062 | 64 ++++++++++++++++++++++++++++++++++++++++++++++++ tests/qemu-iotests/group | 1 + 3 files changed, 100 insertions(+), 17 deletions(-) create mode 100755 tests/qemu-iotests/062 -- 1.8.3.1
