[libvirt] [PATCH v2] Perform disk config validity checking for attach-device config

[Ján Tomko]

On 08/07/2014 04:53 PM, John Ferlan wrote:
> https://bugzilla.redhat.com/show_bug.cgi?id=1078126
> 
> Using 'virsh attach-device --config' (or --persistent) to attach a
> file backed lun device will succeed; however, subsequent domain restarts
> will result in failure because the configuration of a file backed lun
> is not supported.
> 
> Although allowing 'illegal configurations' is something that can be
> allowed, it may not be practical in this case. Generally, when attaching
> a device to a domain means the domain must be running. A way around
> this is using the --config (or --persistent) option. When an attach
> is done to a running domain, a temporary configuration is modified
> first followed by the live update. The live update will make a number
> of disk validity checks when building the qemu command to attach the
> disk. If any fail, then change is rejected.
> 
> Rather than allow a potentially illegal combination, adjust the code
> in the configuration path to make the same checks as the running path
> will make with respect to disk validity checks. This way we avoid
> having the potential for some subsequent start/reboot to fail because
> an illegal combination was allowed.
> 
> NB: The live path still checks the configuration since it is possible
> to just do --live guest modification...
> 
> Signed-off-by: John Ferlan <jferlan at redhat.com>
> ---
> 
> Changes since V1:
> http://www.redhat.com/archives/libvir-list/2014-August/msg00045.html
> 
> Based on #virt IRC discussion this morning 
> - move the qemu_caps checking to only occur during the live check
> - slightly change the name of the called routine
> 
>  src/qemu/qemu_command.c | 127 +++++++++++++++++++++++++++---------------------
>  src/qemu/qemu_command.h |   2 +
>  src/qemu/qemu_driver.c  |   2 +
>  3 files changed, 76 insertions(+), 55 deletions(-)
> 
> diff --git a/src/qemu/qemu_command.c b/src/qemu/qemu_command.c
> index 033a5a8..c1791d9 100644
> --- a/src/qemu/qemu_command.c
> +++ b/src/qemu/qemu_command.c
> @@ -3230,6 +3230,73 @@ qemuGetDriveSourceString(virStorageSourcePtr src,
>  }
>  
>  
> +/* Perform disk definition config validity checks */
> +int
> +qemuBuildCheckDiskConfig(virDomainDiskDefPtr disk)

Just a nitpick:
'Build' seems redundant here, how about just 'qemuCheckDiskConfig'?

ACK either way.

Jan


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