On 09/30/2011 02:52 PM, Eric Blake wrote:
Implements the documentation for snapshot revert vs. force.
Part of the patch tightens existing behavior (previously, reverting
to an old snapshot without<domain> was blindly attempted, now it
requires force), while part of it relaxes behavior (previously, it
was not possible to revert an active domain to an ABI-incompatible
active snapshot, now force allows this transition).
* src/qemu/qemu_driver.c (qemuDomainRevertToSnapshot): Check for
risky situations, and allow force to get past them.
---
src/qemu/qemu_driver.c | 47 +++++++++++++++++++++++++++++++++++++----------
1 files changed, 37 insertions(+), 10 deletions(-)
diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
index 5110102..efd60a7 100644
--- a/src/qemu/qemu_driver.c
+++ b/src/qemu/qemu_driver.c
@@ -9753,7 +9753,8 @@ static int qemuDomainRevertToSnapshot(virDomainSnapshotPtr snapshot,
* 7. paused -> inactive: EVENT_STOPPED
* 8. paused -> running: EVENT_RESUMED
* 9. paused -> paused: none
- * Also, several transitions occur even if we fail partway through.
+ * Also, several transitions occur even if we fail partway through,
+ * and use of FORCE can cause multiple transitions.
*/
qemuDriverLock(driver);
@@ -9789,6 +9790,24 @@ static int qemuDomainRevertToSnapshot(virDomainSnapshotPtr snapshot,
"yet"));
goto cleanup;
}
+ if (!(flags& VIR_DOMAIN_SNAPSHOT_REVERT_FORCE)) {
+ if (!snap->def->dom) {
+ qemuReportError(VIR_ERR_SNAPSHOT_REVERT_RISKY,
+ _("snapshot lacks domain '%s' rollback details"),
+ snap->def->name);
+ goto cleanup;
+ }
+ if (virDomainObjIsActive(vm)&&
+ !(snap->def->state == VIR_DOMAIN_RUNNING
+ || snap->def->state == VIR_DOMAIN_PAUSED)&&
+ (flags& (VIR_DOMAIN_SNAPSHOT_REVERT_RUNNING |
+ VIR_DOMAIN_SNAPSHOT_REVERT_PAUSED))) {
+ qemuReportError(VIR_ERR_SNAPSHOT_REVERT_RISKY,
+ _("must respawn qemu to start inactive snapshot"));
+ goto cleanup;
+ }
+ }
+
if (vm->current_snapshot) {
vm->current_snapshot->def->current = false;
@@ -9818,11 +9837,6 @@ static int qemuDomainRevertToSnapshot(virDomainSnapshotPtr snapshot,
VIR_FREE(xml);
if (!config)
goto cleanup;
- } else {
- /* XXX Fail if VIR_DOMAIN_REVERT_FORCE is not set, rather than
- * blindly hoping for the best. */
- VIR_WARN("snapshot is lacking rollback information for domain '%s'",
- snap->def->name);
}
if (qemuDomainObjBeginJobWithDriver(driver, vm, QEMU_JOB_MODIFY)< 0)
@@ -9843,10 +9857,22 @@ static int qemuDomainRevertToSnapshot(virDomainSnapshotPtr snapshot,
/* Transitions 5, 6, 8, 9 */
/* Check for ABI compatibility. */
if (config&& !virDomainDefCheckABIStability(vm->def, config)) {
- /* XXX Add VIR_DOMAIN_REVERT_FORCE to permit killing
- * and restarting a new qemu, since loadvm monitor
- * command won't work. */
- goto endjob;
+ if (!(flags& VIR_DOMAIN_SNAPSHOT_REVERT_FORCE)) {
+ /* Alter existing error to give correct category. */
+ virErrorPtr err = virGetLastError();
+ err->code = VIR_ERR_SNAPSHOT_REVERT_RISKY;
+ goto endjob;
+ }
+ qemuProcessStop(driver, vm, 0,
+ VIR_DOMAIN_SHUTOFF_FROM_SNAPSHOT);
+ virDomainAuditStop(vm, "from-snapshot");
+ detail = VIR_DOMAIN_EVENT_STOPPED_FROM_SNAPSHOT;
+ event = virDomainEventNewFromObj(vm,
+ VIR_DOMAIN_EVENT_STOPPED,
+ detail);
+ if (event)
+ qemuDomainEventQueue(driver, event);
+ goto load;
}
priv = vm->privateData;
@@ -9882,6 +9908,7 @@ static int qemuDomainRevertToSnapshot(virDomainSnapshotPtr snapshot,
virDomainObjAssignDef(vm, config, false);
} else {
/* Transitions 2, 3 */
+ load:
was_stopped = true;
if (config)
virDomainObjAssignDef(vm, config, false);
ACK.
--
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