Re: [Qemu-devel] [PATCH 0/3] block: Fix is_allocated() for truncated images

[Max Reitz <mreitz@redhat.com>]

On 16.08.2014 20:54, Max Reitz wrote:
> Patch 2:
> The bdrv_is_allocated() functions may return a number of zero sectors
> e.g. if a sector beyond the image end has been queried. Respect this
> case in qemu-io's map implementation so it doesn't run into an infinite
> loop (https://bugs.launchpad.net/qemu/+bug/1356969).
>
> Patch 1:
> In that bug report, bdrv_co_get_block_status() fell through to the
> underlying file to get additional information (whether the sectors are
> zeroed). However, the offset reported by the image format (qcow2) was
> beyond the size of the underlying file and so this second query returned
> only zero clusters which replaced the actual number of sectors queried
> in the "formatted" (on qcow2 level) image. But because errors from this
> second call are ignored, the number of sector queried successfully
> should be ignored as well, which makes qemu-io -c map actually work for
> that bug report.
>
> Patch 3 adds a test for patch 1; I could not conceive a test for patch 2
> which patch 1 would not already catch, but patch 2 should be simple
> enough not to require a test anyway.
>
> Thanks to patch 3, this series depends on my previous series
> "[PATCH v10 00/14] qemu-img: Implement commit like QMP"
> (strictly speaking only on patch 11 of that series which adds
> _filter_qemu_img_map() to tests/qemu-iotests/common.filter).
>
>
> Max Reitz (3):
>    block: Ignore allocation size in underlying file
>    qemu-io: Respect early image end for map
>    iotests: Add test for map commands
>
>   block.c                    |  6 +++--
>   qemu-io-cmds.c             |  5 +++-
>   tests/qemu-iotests/102     | 64 ++++++++++++++++++++++++++++++++++++++++++++++
>   tests/qemu-iotests/102.out | 11 ++++++++
>   tests/qemu-iotests/group   |  1 +
>   5 files changed, 84 insertions(+), 3 deletions(-)
>   create mode 100755 tests/qemu-iotests/102
>   create mode 100644 tests/qemu-iotests/102.out
>

Ping.