On 03/19/2012 04:04 AM, Michal Privoznik wrote:
On 16.03.2012 21:49, Eric Blake wrote:
If a guest is paused, we were silently ignoring the quiesce flag, which results in unclean snapshots, contrary to the intent of the flag. Since we can't quiesce without guest agent support, we should instead fail if the guest is not running.
Meanwhile, if we attempt a quiesce command, but the guest agent doesn't respond, and we time out, we may have left the command pending on the guest's queue, and when the guest resumes parsing commands, it will freeze even though our command is no longer around to issue a thaw. To be safe, we must _always_ pair every quiesce call with a counterpart thaw, even if the quiesce call failed due to a timeout, so that if a guest wakes up and starts processing a command backlog, it will not get stuck in a frozen state.
* src/qemu/qemu_driver.c (qemuDomainSnapshotCreateDiskActive): Always issue thaw after a quiesce, even if quiesce failed. (qemuDomainSnapshotFSThaw): Add a parameter. ---
See also: https://bugzilla.redhat.com/show_bug.cgi?id=804210 https://www.redhat.com/archives/libvir-list/2012-March/msg00708.html
src/qemu/qemu_driver.c | 51 +++++++++++++++++++++++++++++++++-------------- 1 files changed, 36 insertions(+), 15 deletions(-)
ACK this and the follow up patch as well.
Thanks; pushed. -- Eric Blake eblake@redhat.com +1-919-301-3266 Libvirt virtualization library http://libvirt.org