Re: [PATCH v2] Consider discard option when writing zeros

[Kevin Wolf]

Am 24.06.2024 um 17:23 hat Stefan Hajnoczi geschrieben:
> On Wed, Jun 19, 2024 at 08:43:25PM +0300, Nir Soffer wrote:
> > Tested using:
> 
> Hi Nir,
> This looks like a good candidate for the qemu-iotests test suite. Adding
> it to the automated tests will protect against future regressions.
> 
> Please add the script and the expected output to
> tests/qemu-iotests/test/write-zeroes-unmap and run it using
> `(cd build && tests/qemu-iotests/check write-zeroes-unmap)`.
> 
> See the existing test cases in tests/qemu-iotests/ and
> tests/qemu-iotests/tests/ for examples. Some are shell scripts and
> others are Python. I think shell makes sense for this test case. You
> can copy the test framework boilerplate from an existing test case.

'du' can't be used like this in qemu-iotests because it makes
assumptions that depend on the filesystem. A test case replicating what
Nir did manually would likely fail on XFS with its preallocation.

Maybe we could operate on a file exposed by the FUSE export that is
backed by qcow2, and then you can use 'qemu-img map' on that qcow2 image
to verify the allocation status. Somewhat complicated, but I think it
could work.

Kevin

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