Re: [libvirt] [PATCHv3 13/43] snapshot: prevent stranding snapshot data on domain destruction
On 08/24/2011 10:56 AM, Eric Blake wrote:
>> + VIR_DOMAIN_DESTROY_SNAPSHOTS_FULL = (1<< 2), /* If
last use of domain,
>> + then also remove any
>> + snapshot data */
But I am starting to be convinced by your assertion that this is
dangerous - there is no way to cleanly report partial failure with a
flag like this, which means that in the failure case, it did not add any
convenience, but made things worse.
[perhaps this email is more for my reference than anything else, since I
am using the giant thread and all replies in it to track what I still
need to do before v4 is ready...]
https://www.redhat.com/archives/libvir-list/2011-August/msg01355.html
had more arguments on which flags are most appropriate; the consensus
there was that snapshot metadata should be automatically deleted on the
last reference to a domain (such as shutting down a transient domain),
and that only undefine of a persistent domain should fail because
snapshot metadata exists (for all other situations, the auto-deletion of
metadata is sufficient). Meanwhile, I also need to guarantee that it is
possible to reload snapshot state from external sources (i.e. allow a
snapshot redefinition to reinstate metadata). My holdup for posting a
v4 of this series is getting all that added, but I will keep my git
repository up-to-date with the latest state of my series as I keep
posting stream-of-development patches as replies into this v3 series.
--
Eric Blake eblake(a)redhat.com +1-801-349-2682
Libvirt virtualization library http://libvirt.org