Re: [RFC V7 3/3] xl snapshot-xxx Design

[Ian Campbell <Ian.Campbell@citrix.com>]

On Wed, 2014-10-29 at 02:34 -0600, Chun Yan Liu wrote:
> >> > "xl snapshot-delete"  
> >> >   
> >> >     1), read snapshot json file from  
> >> >         "/var/lib/xen/snapshots/domain_uuid/snapshotdata-<snapshot_name>\  
> >> >         .libxl-json", parse the file and fill in libxl_domain_snapshot_info  
> >>   
> >> >         and commandline options, decide which domain snapshot to be   
> >> deleted.  
> >> >         To delete each domain snapshot, fill in  
> >> >         libxl_domain_snapshot_args and call libxl_domain_snapshot_delete().  
> >>   
> >> Depending on the state of the domain, much of this can be done with  
> >> unlink and/or calling out to external tools.  
> >  
> > Yes, xl or libvirt application can delete memory state file and delete 
> > disk snapshot (eg. call qemu-img to delete internal disk snapshot instead 
> > of qmp command, or delete external snapshot directly). 
> > Just both xl and libvirt do the same work repeatly. So, I propose 
> > libxl_domain_snapshot_delete API. Keep it or not? 
> 
> And here, any suggestion?

If it weren't for the need to do "storage management" in libxl (i.e.
call qemu-img) this would seem like a harmless enough helper. However
the need for it to do storage mgmt is concerning, since it means libxl
needs to learn more about the details of each container format it might
support using as a backend.

Perhaps it is a candidate for libxlu rather than libxl proper?