On 28.10.19 17:18, Max Reitz wrote: > This fixes a bug reported on > https://bugs.launchpad.net/qemu/+bug/1850000. The problem is that > QCOW2_COMPRESSED_SECTOR_MASK is a 32-bit mask when it really needs to be > a 64-bit mask. > > The launchpad report mentions only problems with qemu-img check on large > compressed images, but I think it might extend further than that: > - I suppose qcow2_free_any_clusters() would free every compressed offset > modulo 4G, which isn’t good > - qcow2_update_snapshot_refcount() will probably update compressed > cluster’s refcounts (in snapshots) modulo 4G, which also isn’t good > - And then we have check_refcount_l2() which updates the wrong clusters > for qemu-img check (as demonstrated in the bug report) > > - (qcow2_co_preadv_compressed() is safe because it uses the inverted > mask, which of course is again just 32 bit) > > > But I haven’t tested those other cases. > > > Max Reitz (2): > qcow2: Fix QCOW2_COMPRESSED_SECTOR_MASK > iotests: Add test for 4G+ compressed qcow2 write > > block/qcow2.h | 2 +- > tests/qemu-iotests/272 | 79 ++++++++++++++++++++++++++++++++++++++ > tests/qemu-iotests/272.out | 10 +++++ > tests/qemu-iotests/group | 1 + > 4 files changed, 91 insertions(+), 1 deletion(-) > create mode 100755 tests/qemu-iotests/272 > create mode 100644 tests/qemu-iotests/272.out
Thanks for the review, applied to my block branch: https://git.xanclic.moe/XanClic/qemu/commits/branch/block Max
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