On 12/23/2015 12:46 AM, Denis V. Lunev wrote: > From: Olga Krishtal <okrish...@virtuozzo.com> > > While opening the image we want to be sure that we are the > one who works with image, anf if it is not true -
s/anf/and/
> opening the image for writing should fail.
>
> There are 2 ways at the moment: no lock at all and lock the file
> image.
>
> Signed-off-by: Olga Krishtal <okrish...@virtuozzo.com>
> Signed-off-by: Denis V. Lunev <d...@openvz.org>
> CC: Kevin Wolf <kw...@redhat.com>
> CC: Max Reitz <mre...@redhat.com>
> CC: Eric Blake <ebl...@redhat.com>
> CC: Fam Zheng <f...@redhat.com>
> ---
> @@ -895,6 +897,12 @@ static QemuOptsList bdrv_runtime_opts = {
> .type = QEMU_OPT_BOOL,
> .help = "Ignore flush requests",
> },
> + {
> + .name = "lock",
> + .type = QEMU_OPT_STRING,
> + .help = "How to lock the image: none or lockfile",
> + .def_value_str = "none",
If locking is not on by default, then it is not providing the protection
we want. Having multiple lock styles doesn't help much - advisory
locking is only useful if all clients use the same style.
> +++ b/qapi/block-core.json
> @@ -2408,3 +2408,12 @@
> ##
> { 'command': 'block-set-write-threshold',
> 'data': { 'node-name': 'str', 'write-threshold': 'uint64' } }
> +
> +##
> +# @BdrvLockImage:
> +#
> +#An enumeration of lock types to lock image file.
> +# @none - do not lock the image file
> +# @lockfile
I know you said this series was rough, but you didn't document much
about what lockfile means.
> +## Since 2.6
> +{ 'enum': 'BdrvLockImage', 'data':['none', 'lockfile']}
>
--
Eric Blake eblake redhat com +1-919-301-3266
Libvirt virtualization library http://libvirt.org
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