Re: [Qemu-devel] [PATCH v3 3/6] qemu-iotests: Add _supported_cache_modes

[Fam Zheng]

On 2013年11月21日 20:39, Stefan Hajnoczi wrote:
> On Wed, Nov 20, 2013 at 03:44:14PM +0800, Fam Zheng wrote:
> > -_unsupported_qemu_io_options()
> > +_supported_cache_modes()
> >   {
> > -    for bad_opt
> > -    do
> > -        for opt in $QEMU_IO_OPTIONS
> > -        do
> > -            if [ "$bad_opt" = "$opt" ]
> > -            then
> > -                _notrun "not suitable for qemu-io option: $bad_opt"
> > -            fi
> > -        done
> > +    if $CACHEMODE_IS_DEFAULT; then
> > +        QEMU_IO="$QEMU_IO -t $1"
> > +        return
> > +    fi
> > +    for mode; do
> > +        if [ "$mode" = "$CACHEMODE" ]; then
> > +            return
> > +        fi
> >       done
> > +    _notrun "not suitable for cache mode: $CACHEMODE"
> >   }
>
> This seems weird to me:
> By default tests run with CACHEMODE=writethrough but test cases can use
> _supported_cache_modes() to switch to a different "default" behind the
> scenes?
>
> Why not keep it simple:
> If a test doesn't support CACHEMODE, it gets skipped.

I thought Kevin wanted to override the cache mode (if not given by 
user), so the cases doesn't get skipped by default. I also feel that a 
test case used to actually run by default shouldn't be skipped unnoticed.

I'm basically adding a meta cache mode "default" here, which means we 
will not have a "implicit yet forced" cache mode any more.

On 2013年11月19日 18:21, Kevin Wolf wrote:
>
> Okay, I gave it some testing, too, and it looks like we need some
> additional changes. There are some test cases that use:
>
> _unsupported_qemu_io_options --nocache
>
> Which obviously doesn't work any more. We need to replace it by a check
> against $CACHEMODE (or, perhaps preferably, even override it
> automatically, so that test cases aren't left out just because of the
> cache mode)
>
> Test case 026 uses the option of having a 026.out.nocache, which differs
> from the normal output. I suspect the correct differentiation is here
> between writethrough and writeback modes. And of course, grepping for
> '--nocache' to detect the condition doesn't work any more.
>
> Kevin
>

Fam