Re: [PATCH] iotests: don't run tests requiring cached writes in '-nocache' mode

[Eric Blake]

On Mon, Dec 11, 2023 at 03:32:23PM +0200, Andrey Drobyshev wrote:
> There're tests whose logic implies running without O_DIRECT set,
> otherwise they fail when running iotests in '-nocache' mode.  For these
> tests let's add _require_no_o_direct() helper which can be put in the
> preabmle and which makes sure '-nocache' isn't set.  Use it to skip

preamble

> running the following tests:
> 
>   * 271: creates files with unaligned sizes, thus producing multiple
>     errors like:
> 
> qemu-io: can't open device /path/to/t.qcow2.raw: Cannot get 'write'
> permission without 'resize': Image size is not a multiple of request alignment

I wonder if we can instead tweak the test to use larger sizes such
that all accesses ARE aligned even with O_DIRECT.

/me goes and reads the test...

    # Note that the image size is not a multiple of the cluster size
    _reset_img 2083k

Ah - we really DO have a test that depends on odd sizing; where
changing it to be more nicely aligned will break other assumptions in
the test.

> 
>   * 308, file-io-error: use fuse exports.  Though fuse does have
>     'direct-io' mode (see https://docs.kernel.org/filesystems/fuse-io.html)
>     we aren't using it yet, thus getting errors like:
> 
> qemu-io: can't open device /path/to/t.qcow2.fuse: Could not open
> '/path/to/t.qcow2.fuse': filesystem does not support O_DIRECT

And I agree that this one is beyond our control, so adding skip
support makes sense.

> 
> Signed-off-by: Andrey Drobyshev <andrey.drobyshev@virtuozzo.com>
> ---
>  tests/qemu-iotests/271                 | 1 +
>  tests/qemu-iotests/308                 | 2 ++
>  tests/qemu-iotests/common.rc           | 7 +++++++
>  tests/qemu-iotests/tests/file-io-error | 1 +
>  4 files changed, 11 insertions(+)

Reviewed-by: Eric Blake <eblake@redhat.com>

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.
Virtualization:  qemu.org | libguestfs.org