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Re: [Qemu-devel] [PATCH 00/11] block: Use BB function in .bdrv_create()
From: |
Kevin Wolf |
Subject: |
Re: [Qemu-devel] [PATCH 00/11] block: Use BB function in .bdrv_create() implementations |
Date: |
Mon, 14 Mar 2016 18:34:31 +0100 |
User-agent: |
Mutt/1.5.21 (2010-09-15) |
Am 14.03.2016 um 17:55 hat Max Reitz geschrieben:
> On 14.03.2016 12:31, Kevin Wolf wrote:
> > Am 08.03.2016 um 17:34 hat Kevin Wolf geschrieben:
> >> All users of the block layers are supposed to go through a BlockBackend.
> >> The .bdrv_create() implementations are such users, so this series
> >> converts them.
> >>
> >> This series (specifically patch 1) will also help with moving the
> >> writethrough cache implementation from BDS to BB, where it really
> >> belongs. Once this is moved, it wouldn't be possible to use bdrv_open()
> >> to use a standalone BDS writethrough any more.
> >>
> >> Of course, writethrough doesn't make any sense in .bdrv_create() anyway,
> >> so while I'm still converting everything to BB where it would keep
> >> working (because that's the Right Thing), the drivers don't actually
> >> make use of this fact any more after this series.
> >
> > Applied to the block branch.
>
> Now you can't name any BB "image" any more if you want to use e.g.
> drive-mirror. Intended?
Not really. :-/
Of course, you're supposed to use blockdev-mirror anyway (does it even
exist?), but we should avoid that. Fortunately, your "Further BB work"
will tie the name to a monitor reference and BBs without a name become
valid then, I think.
So this might be a good excuse for getting that series into 2.6. :-)
Kevin
> Example:
>
> $ x86_64-softmmu/qemu-system-x86_64 -drive
> if=none,id=image,file=null-co://,driver=raw -qmp stdio
> {'execute':'qmp_capabilities'}
> {"return": {}}
> {'execute':'drive-mirror','arguments':{'device':'image','target':'foo.qcow2','sync':'full','format':'qcow2'}}
> Formatting 'foo.qcow2', fmt=qcow2 size=1073741824 encryption=off
> cluster_size=65536 lazy_refcounts=off refcount_bits=16
> {"error": {"class": "GenericError", "desc": "Device with id 'image'
> already exists"}}
>
> Max
>
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- [Qemu-devel] [PATCH 08/11] vdi: Use BB functions in .bdrv_create(), (continued)
- [Qemu-devel] [PATCH 08/11] vdi: Use BB functions in .bdrv_create(), Kevin Wolf, 2016/03/08
- [Qemu-devel] [PATCH 09/11] vhdx: Use BB functions in .bdrv_create(), Kevin Wolf, 2016/03/08
- [Qemu-devel] [PATCH 06/11] qed: Use BB functions in .bdrv_create(), Kevin Wolf, 2016/03/08
- [Qemu-devel] [PATCH 01/11] block: Use writeback in .bdrv_create() implementations, Kevin Wolf, 2016/03/08
- [Qemu-devel] [PATCH 11/11] vpc: Use BB functions in .bdrv_create(), Kevin Wolf, 2016/03/08
- [Qemu-devel] [PATCH 10/11] vmdk: Use BB functions in .bdrv_create(), Kevin Wolf, 2016/03/08
- Re: [Qemu-devel] [PATCH 00/11] block: Use BB function in .bdrv_create() implementations, Kevin Wolf, 2016/03/14