On Thu, Nov 7, 2013 at 11:39 AM, Eric Blake <eblake@redhat.com> wrote:
On 11/06/2013 05:31 PM, Tomoki Sekiyama wrote:
Hi all,
Is there any plans to add APIs to execute fsfreeze/fsthaw in qemu guests? (something like virDomainFSFreeze(domain,timeout,flags) and virDomainFSThaw(domain,timeout,flags))
I'm wondering if it might be better to have a single command with a callback argument, something like:
virDomainQuiese(domain, timeout, callback, opaque, flags)
which calls callback(domain, opaque) at the right point in time. I'm just a bit worried that since the freeze/thaw sequence is already handled as a pair by the QUIESCE flag of snapshot creation that exposing it as two non-atomic APIs may lead to inconsistent states that we'd have a hard time tracking which commands are allowed in which state. With only a single command and a callback, we have guaranteed semantics that all other API are locked out by our normal job mechanism, and that we can pair the freeze/thaw under the hood just as we do in snapshots.
I think this is a much better approach. We could arguably refactor the snapshot code to use this as well. -- Doug Goldstein