Re: [Qemu-devel] [PATCH] block migration: Allow compile time disable

[Eric Blake]

On 05/03/2017 05:42 AM, Dr. David Alan Gilbert (git) wrote:
> From: "Dr. David Alan Gilbert" <address@hidden>
> 
> Many users now prefer to use drive_mirror over NBD as an
> alternative to the older migrate -b option; drive_mirror is
> more complex to setup but gives you more options (e.g. only
> migrating some of the disks if some of them are shared).
> 
> Allow the large chunk of block migration code to be compiled
> out for those who don't use it.
> 
> Based on a downstream-patch we've had for a while by Jeff Cody.
> 
> Signed-off-by: Dr. David Alan Gilbert <address@hidden>
> ---
> @@ -1222,6 +1226,14 @@ void qmp_migrate(const char *uri, bool has_blk, bool 
> blk,
>      params.blk = has_blk && blk;
>      params.shared = has_inc && inc;
>  
> +#ifndef CONFIG_LIVE_BLOCK_MIGRATION
> +    if (params.blk || params.shared) {
> +        error_setg(errp, "QEMU compiled without old-style block migration. "
> +                         "Use drive_mirror+NBD.");

error_setg() should not be used with '.' (it should be a single phrase,
here you are trying to stuff in two sentences).  error_append_hint() can
be used to supply the advice about using drive_mirror+NBD as the
alternative.

Otherwise this looks reasonable to me.

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3266
Virtualization:  qemu.org | libvirt.org

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