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Re: [Qemu-devel] [PATCH V2 5/8] block/qcow2: read and write the compress
From: |
Daniel P. Berrange |
Subject: |
Re: [Qemu-devel] [PATCH V2 5/8] block/qcow2: read and write the compress format extension |
Date: |
Thu, 13 Jul 2017 16:06:52 +0100 |
User-agent: |
Mutt/1.8.3 (2017-05-23) |
On Thu, Jul 13, 2017 at 05:02:51PM +0200, Peter Lieven wrote:
> Am 13.07.2017 um 17:01 schrieb Daniel P. Berrange:
> > On Thu, Jul 13, 2017 at 05:00:39PM +0200, Peter Lieven wrote:
> > > Am 13.07.2017 um 16:58 schrieb Daniel P. Berrange:
> > > > On Thu, Jul 13, 2017 at 04:18:13PM +0200, Peter Lieven wrote:
> > > > > Okay, so it has to be a mix of QAPI parsing and manual parameter
> > > > > checking,
> > > > > right?
> > > > Yeah. It does feel like a valid RFE for QAPI to add a permitted range to
> > > > 'int' types though, which would simplify the code in future.
> > > >
> > > > > I currently have the following:
> > > > >
> > > > > options = qemu_opts_to_qdict(opts, NULL);
> > > > > qdict_extract_subqdict(options, &compressopts, "compress.");
> > > > > v = qobject_input_visitor_new_keyval(QOBJECT(compressopts));
> > > > > visit_start_struct(v, NULL, NULL, 0, &local_err);
> > > > > if (local_err) {
> > > > > ret= -EINVAL;
> > > > > goto finish;
> > > > > }
> > > > > visit_type_Qcow2Compress_members(v, &compress, &local_err);
> > > > > if (local_err) {
> > > > > ret= -EINVAL;
> > > > > goto finish;
> > > > > }
> > > > > visit_end_struct(v, NULL);
> > > > > visit_free(v);
> > > > > QDECREF(compressopts);
> > > > > QDECREF(options)
> > > > Looks good.
> > > >
> > > > > And I have the following 2 questions:
> > > > > a) I have to specifiy compress.format and compress.level otherwise
> > > > > I will get an error. How can I fix that the settings are optional?
> > > > Put an '*' as the first character of any field name if it should be
> > > > optional.
> > > >
> > > > > b) If I just specify a compress.format can I default the
> > > > > compress.level to 0 without an error?
> > > > I believe you'd get compress.level as 0 automatically for an 'int' type.
> > > I still face the issue that I now always have to specify a
> > > compress.format.
> > > I tried to solve it like this:
> > [snip]
> >
> > that's not needed if you name the parameter '*level' in the QAPI schema
>
> its not needed for the *level, but I still get the error that the format
> parameter is missing otherwise. And I can't make format optional.
Surely specifying compress.format is how you turn on compression in the
first place, so making that optional should not be necessary. eg the
simple case becomes:
qemu-img create -f qcow2 -o compress.format=zlib foo.qcow2 1G
Yes, there is no notion of a "default" format, but IMHO that's a good
thing - same way with encryption - it requires an explict encrypt.format=luks
to turn on encryption
Regards,
Daniel
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- Re: [Qemu-devel] [PATCH V2 5/8] block/qcow2: read and write the compress format extension, (continued)
- Re: [Qemu-devel] [PATCH V2 5/8] block/qcow2: read and write the compress format extension, Daniel P. Berrange, 2017/07/13
- Re: [Qemu-devel] [PATCH V2 5/8] block/qcow2: read and write the compress format extension, Peter Lieven, 2017/07/13
- Re: [Qemu-devel] [PATCH V2 5/8] block/qcow2: read and write the compress format extension, Daniel P. Berrange, 2017/07/13
- Re: [Qemu-devel] [PATCH V2 5/8] block/qcow2: read and write the compress format extension, Peter Lieven, 2017/07/13
- Re: [Qemu-devel] [PATCH V2 5/8] block/qcow2: read and write the compress format extension, Daniel P. Berrange, 2017/07/13
- Re: [Qemu-devel] [PATCH V2 5/8] block/qcow2: read and write the compress format extension, Peter Lieven, 2017/07/13
- Re: [Qemu-devel] [PATCH V2 5/8] block/qcow2: read and write the compress format extension, Daniel P. Berrange, 2017/07/13
- Re: [Qemu-devel] [PATCH V2 5/8] block/qcow2: read and write the compress format extension, Peter Lieven, 2017/07/13
- Re: [Qemu-devel] [PATCH V2 5/8] block/qcow2: read and write the compress format extension, Daniel P. Berrange, 2017/07/13
- Re: [Qemu-devel] [PATCH V2 5/8] block/qcow2: read and write the compress format extension, Peter Lieven, 2017/07/13
- Re: [Qemu-devel] [PATCH V2 5/8] block/qcow2: read and write the compress format extension,
Daniel P. Berrange <=
- Re: [Qemu-devel] [PATCH V2 5/8] block/qcow2: read and write the compress format extension, Peter Lieven, 2017/07/13
- Re: [Qemu-devel] [PATCH V2 5/8] block/qcow2: read and write the compress format extension, Daniel P. Berrange, 2017/07/13
- Re: [Qemu-devel] [PATCH V2 5/8] block/qcow2: read and write the compress format extension, Peter Lieven, 2017/07/13
- Re: [Qemu-devel] [PATCH V2 5/8] block/qcow2: read and write the compress format extension, Eric Blake, 2017/07/13