[libvirt] [PATCH] qemu: Fix startupPolicy regression

[Guannan Ren]

On 03/18/2013 09:18 PM, Jiri Denemark wrote:
> Commit 82d5fe543720da6d83c1d6bfa1c347d7d9fda278
>
>      qemu: check backing chains even when cgroup is omitted
>
> added backing file checks just before the code that removes optional
> disks if they are not present. However, the backing chain code fails in
> case the disk file does not exist, which makes qemuProcessStart fail
> regardless on configured startupPolicy.
>
> Note that startupPolicy implementation is still wrong after this patch
> since it only check the first file in a possible chain. It should rather
> check the complete backing chain. But this is an existing limitation
> that can be solved later. After all, startupPolicy is most useful for
> CDROM images and they won't make use of backing files in most cases.
> ---
>   src/qemu/qemu_process.c | 7 ++++---
>   1 file changed, 4 insertions(+), 3 deletions(-)
>
> diff --git a/src/qemu/qemu_process.c b/src/qemu/qemu_process.c
> index 1941d4e..3d2b7d6 100644
> --- a/src/qemu/qemu_process.c
> +++ b/src/qemu/qemu_process.c
> @@ -3621,14 +3621,15 @@ int qemuProcessStart(virConnectPtr conn,
>           goto cleanup;
>   
>       VIR_DEBUG("Checking for CDROM and floppy presence");
> +    if (qemuDomainCheckDiskPresence(driver, vm,
> +                                    flags & VIR_QEMU_PROCESS_START_COLD) < 0)
> +        goto cleanup;
> +
>       for (i = 0; i < vm->def->ndisks ; i++) {
>           if (qemuDomainDetermineDiskChain(driver, vm->def->disks[i],
>                                            false) < 0)
>               goto cleanup;
>       }
> -    if (qemuDomainCheckDiskPresence(driver, vm,
> -                                    flags & VIR_QEMU_PROCESS_START_COLD) < 0)
> -        goto cleanup;
>   
>       /* Get the advisory nodeset from numad if 'placement' of
>        * either <vcpu> or <numatune> is 'auto'.

     This fix is also in my patch set, so I give ACK.
https://www.redhat.com/archives/libvir-list/2013-March/msg00990.html

     Guannan