Am 16.07.2024 um 16:41 hat Andrey Drobyshev geschrieben:
> The testcase simply creates a 64G image with 1M clusters, generates a list
> of 1M aligned offsets and feeds aio_write commands with those offsets to
> qemu-io run with '--aio native --nocache'. Then we check the data
> written at each of the offsets. Before the previous commit this could
> result into a race within the preallocation filter which would zeroize
> some clusters after actually writing data to them.
>
> Note: the test doesn't fail in 100% cases as there's a race involved,
> but the failures are pretty consistent so it should be good enough for
> detecting the problem.
>
> Signed-off-by: Andrey Drobyshev <andrey.drobys...@virtuozzo.com>
I left it running in a loop for a while, but couldn't reproduce the bug
with this test.
> tests/qemu-iotests/298 | 49 ++++++++++++++++++++++++++++++++++++++
> tests/qemu-iotests/298.out | 4 ++--
> 2 files changed, 51 insertions(+), 2 deletions(-)
>
> diff --git a/tests/qemu-iotests/298 b/tests/qemu-iotests/298
> index 09c9290711..b7126e9e15 100755
> --- a/tests/qemu-iotests/298
> +++ b/tests/qemu-iotests/298
> @@ -20,8 +20,10 @@
>
> import os
> import iotests
> +import random
>
> MiB = 1024 * 1024
> +GiB = MiB * 1024
> disk = os.path.join(iotests.test_dir, 'disk')
> overlay = os.path.join(iotests.test_dir, 'overlay')
> refdisk = os.path.join(iotests.test_dir, 'refdisk')
> @@ -176,5 +178,52 @@ class TestTruncate(iotests.QMPTestCase):
> self.do_test('off', '150M')
>
>
> +class TestPreallocAsyncWrites(iotests.QMPTestCase):
> + def setUp(self):
> + # Make sure we get reproducible write patterns on each run
> + random.seed(42)
> + iotests.qemu_img_create('-f', iotests.imgfmt, disk, '-o',
> + f'cluster_size={MiB},lazy_refcounts=on',
> + str(64 * GiB))
> +
> + def tearDown(self):
> + os.remove(disk)
> +
> + def test_prealloc_async_writes(self):
> + def gen_write_pattern():
> + n = 0
> + while True:
> + yield '-P 0xaa' if n else '-z'
> + n = 1 - n
This looks like a complicated way to write the following?
# Alternate between write_zeroes and writing data
def gen_write_pattern():
while True:
yield '-z'
yield '-P 0xaa'
> + def gen_read_pattern():
> + n = 0
> + while True:
> + yield '-P 0xaa' if n else '-P 0x00'
> + n = 1 - n
Same here.
Kevin
