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.
--
Eric Blake eblake redhat com +1-919-301-3266
Libvirt virtualization library
http://libvirt.org