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Re: [Qemu-block] [PATCH v2 1/2] iotest 033: add misaligned write-zeroes
Re: [Qemu-block] [PATCH v2 1/2] iotest 033: add misaligned write-zeroes test via truncate
Mon, 12 Feb 2018 19:16:14 +0300
Mozilla/5.0 (Windows NT 6.3; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.5.2
On 12/2/2018 6:54 PM, Alberto Garcia wrote:
On Mon 12 Feb 2018 02:14:00 PM CET, Anton Nefedov wrote:
+# Trigger truncate that would shrink qcow2 L1 table, which is done by
+# clearing one entry (8 bytes) with bdrv_co_pwrite_zeroes()
+echo "=== Test misaligned write zeroes via truncate ==="
+CLUSTER_SIZE=$((64 * 1024))
+L2_COVERAGE=$(($CLUSTER_SIZE * $CLUSTER_SIZE / 8))
+_make_test_img $(($L2_COVERAGE * 2))
If my numbers are correct, that's a 1GB image. For qcow2 this is not a
problem but I wonder if it's ok to create such large images for other
formats (for raw they should be sparse by default, but still).
Good point. Actually even 512 byte clusters will work here, resulting
in a just 64k image.