Re: [Qemu-block] [PATCH v11 9/9] tests: Add coverage for recent block geometry fixes

[Max Reitz]

On 29.04.2017 21:14, Eric Blake wrote:
> Use blkdebug's new geometry constraints to emulate setups that
> have needed past 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>
> Reviewed-by: Max Reitz <address@hidden>
> 
> ---
> v11: rebase to context
> v10: no change, rebase to context
> v9: no change
> v7-v8: not submitted (earlier half of series sent for 2.9)
> v6: rebase to master by renumbering s/175/177/
> v5: rebase to master by renumbering s/173/175/
> 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/177     | 114 
> +++++++++++++++++++++++++++++++++++++++++++++
>  tests/qemu-iotests/177.out |  49 +++++++++++++++++++
>  tests/qemu-iotests/group   |   1 +
>  3 files changed, 164 insertions(+)
>  create mode 100755 tests/qemu-iotests/177
>  create mode 100644 tests/qemu-iotests/177.out
> 
> diff --git a/tests/qemu-iotests/177 b/tests/qemu-iotests/177
> new file mode 100755
> index 0000000..e4ddec7
> --- /dev/null
> +++ b/tests/qemu-iotests/177

[...]

> +echo
> +echo "== verify image content =="
> +
> +function verify_io()
> +{
> +    if ($QEMU_IMG info -f "$IMGFMT" "$TEST_IMG" |
> +         grep "compat: 0.10" > /dev/null); then
> +        # For v2 images, discarded clusters are read from the backing file
> +        discarded=11
> +    else
> +        # Discarded clusters are zeroed for v3 or later
> +        discarded=0
> +    fi
> +
> +    echo read -P 22 0 1000
> +    echo read -P 33 1000 128k
> +    echo read -P 22 132072 7871512
> +    echo read -P 0 8003584 2093056
> +    echo read -P 22 10096640 23457792
> +    echo read -P 0 32M 32M
> +    echo read -P 22 64M 13M
> +    echo read -P $discarded 77M 29M
> +    echo read -P 22 106M 22M
> +}
> +
> +verify_io | $QEMU_IO "$TEST_IMG" | _filter_qemu_io

This conflicts with Fam's image locking series that has been introduced
in the meantime (and unfortunately I'm the one who has to base his block
queue on Kevin's...). I suppose it's because the qemu_io process is
launched before the qemu_img info process.

Simply adding an -r to the qemu_io command fixes this, however. I'll do
so in my branch, assuming you're OK with that. :-)

Max

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