Re: [Qemu-block] [PATCH v4 7/7] tests: Add coverage for recent block geometry fixes

[Max Reitz]

On 20.12.2016 20:15, Eric Blake wrote:
> Use blkdebug's new geometry constraints to emulate setups that
> have caused recent regression fixes: write zeroes asserting
> when running through a loopback block device with max-transfer
> smaller than cluster size, and discard rounding away portions
> of requests not aligned to preferred boundaries.  Also, add
> coverage that the block layer is honoring max transfer limits.
> 
> For now, a single iotest performs all actions, with the idea
> that we can add future blkdebug constraint test cases in the
> same file; but it can be split into multiple iotests if we find
> reason to run one portion of the test in more setups than what
> are possible in the other.
> 
> For reference, the final portion of the test (checking whether
> discard passes as much as possible to the lowest layers of the
> stack) works as follows:
> 
> qemu-io: discard 30M at 80000001, passed to blkdebug
>   blkdebug: discard 511 bytes at 80000001, -ENOTSUP (smaller than
> blkdebug's 512 align)
>   blkdebug: discard 14371328 bytes at 80000512, passed to qcow2
>     qcow2: discard 739840 bytes at 80000512, -ENOTSUP (smaller than
> qcow2's 1M align)
>     qcow2: discard 13M bytes at 77M, succeeds
>   blkdebug: discard 15M bytes at 90M, passed to qcow2
>     qcow2: discard 15M bytes at 90M, succeeds
>   blkdebug: discard 1356800 bytes at 105M, passed to qcow2
>     qcow2: discard 1M at 105M, succeeds
>     qcow2: discard 308224 bytes at 106M, -ENOTSUP (smaller than qcow2's
> 1M align)
>   blkdebug: discard 1 byte at 111457280, -ENOTSUP (smaller than
> blkdebug's 512 align)
> 
> Signed-off-by: Eric Blake <address@hidden>
> 
> ---
> v4: clean up some comments, nicer backing file creation, more commit message
> v3: make comments tied more to test at hand, rather than the
> particular hardware that led to the earlier patches being tested
> v2: new patch
> ---
>  tests/qemu-iotests/173     | 114 
> +++++++++++++++++++++++++++++++++++++++++++++
>  tests/qemu-iotests/173.out |  49 +++++++++++++++++++
>  tests/qemu-iotests/group   |   1 +
>  3 files changed, 164 insertions(+)
>  create mode 100755 tests/qemu-iotests/173
>  create mode 100644 tests/qemu-iotests/173.out

Reviewed-by: Max Reitz <address@hidden>

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