4:27 p.m.
The hardest part about adding transactions is not using the new
monitor command, but undoing the partial changes we made prior
to a failed transaction.
* src/qemu/qemu_driver.c (qemuDomainSnapshotCreateDiskActive): Use
transaction when available.
(qemuDomainSnapshotUndoSingleDiskActive): New function.
(qemuDomainSnapshotCreateSingleDiskActive): Pass through actions.
(qemuDomainSnapshotCreateXML): Adjust caller.
---
src/qemu/qemu_driver.c | 112 +++++++++++++++++++++++++++++++++++++++++++++--
1 files changed, 107 insertions(+), 5 deletions(-)
diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
index c3bbc3f..2bc8d5d 100644
--- a/src/qemu/qemu_driver.c
+++ b/src/qemu/qemu_driver.c
@@ -9822,7 +9822,8 @@ qemuDomainSnapshotCreateSingleDiskActive(struct qemud_driver
*driver,
virDomainObjPtr vm,
virDomainSnapshotDiskDefPtr snap,
virDomainDiskDefPtr disk,
- virDomainDiskDefPtr persistDisk)
+ virDomainDiskDefPtr persistDisk,
+ virJSONValuePtr actions)
{
qemuDomainObjPrivatePtr priv = vm->privateData;
char *device = NULL;
@@ -9882,7 +9883,7 @@ qemuDomainSnapshotCreateSingleDiskActive(struct qemud_driver
*driver,
origdriver = NULL;
/* create the actual snapshot */
- ret = qemuMonitorDiskSnapshot(priv->mon, NULL, device, source);
+ ret = qemuMonitorDiskSnapshot(priv->mon, actions, device, source);
virDomainAuditDisk(vm, disk->src, source, "snapshot", ret >= 0);
if (ret < 0)
goto cleanup;
@@ -9923,6 +9924,69 @@ cleanup:
return ret;
}
+/* The domain is expected to hold monitor lock. This is the
+ * counterpart to qemuDomainSnapshotCreateSingleDiskActive, called
+ * only on a failed transaction. */
+static void
+qemuDomainSnapshotUndoSingleDiskActive(struct qemud_driver *driver,
+ virDomainObjPtr vm,
+ virDomainDiskDefPtr origdisk,
+ virDomainDiskDefPtr disk,
+ virDomainDiskDefPtr persistDisk,
+ bool need_unlink)
+{
+ char *source = NULL;
+ char *driverType = NULL;
+ char *persistSource = NULL;
+ char *persistDriverType = NULL;
+ struct stat st;
+
+ if (!(source = strdup(origdisk->src)) ||
+ (origdisk->driverType &&
+ !(driverType = strdup(origdisk->driverType))) ||
+ (persistDisk &&
+ (!(persistSource = strdup(source)) ||
+ (driverType && !(persistDriverType = strdup(driverType)))))) {
+ virReportOOMError();
+ goto cleanup;
+ }
+
+ if (virSecurityManagerRestoreImageLabel(driver->securityManager,
+ vm->def, disk) < 0)
+ VIR_WARN("Unable to restore security label on %s", disk->src);
+ if (virDomainLockDiskDetach(driver->lockManager, vm, disk) < 0)
+ VIR_WARN("Unable to release lock on %s", source);
+ if (need_unlink && stat(disk->src, &st) == 0
+ && st.st_size == 0 && S_ISREG(st.st_mode) &&
unlink(disk->src) < 0)
+ VIR_WARN("Unable to release lock on %s", disk->src);
+
+ /* Update vm in place to match changes. */
+ VIR_FREE(disk->src);
+ disk->src = source;
+ source = NULL;
+ VIR_FREE(disk->driverType);
+ if (driverType) {
+ disk->driverType = driverType;
+ driverType = NULL;
+ }
+ if (persistDisk) {
+ VIR_FREE(persistDisk->src);
+ persistDisk->src = persistSource;
+ persistSource = NULL;
+ VIR_FREE(persistDisk->driverType);
+ if (persistDriverType) {
+ persistDisk->driverType = persistDriverType;
+ persistDriverType = NULL;
+ }
+ }
+
+cleanup:
+ VIR_FREE(source);
+ VIR_FREE(driverType);
+ VIR_FREE(persistSource);
+ VIR_FREE(persistDriverType);
+}
+
/* The domain is expected to be locked and active. */
static int
qemuDomainSnapshotCreateDiskActive(virConnectPtr conn,
@@ -9932,6 +9996,8 @@ qemuDomainSnapshotCreateDiskActive(virConnectPtr conn,
unsigned int flags)
{
virDomainObjPtr vm = *vmptr;
+ qemuDomainObjPrivatePtr priv = vm->privateData;
+ virJSONValuePtr actions = NULL;
bool resume = false;
int ret = -1;
int i;
@@ -9981,9 +10047,17 @@ qemuDomainSnapshotCreateDiskActive(virConnectPtr conn,
goto cleanup;
}
}
+ if (qemuCapsGet(priv->qemuCaps, QEMU_CAPS_TRANSACTION)) {
+ actions = virJSONValueNewArray();
+ if (!actions) {
+ virReportOOMError();
+ goto cleanup;
+ }
+ }
/* No way to roll back if first disk succeeds but later disks
- * fail. Based on earlier qemuDomainSnapshotDiskPrepare, all
+ * fail, unless we have transaction support.
+ * Based on earlier qemuDomainSnapshotDiskPrepare, all
* disks in this list are now either SNAPSHOT_NO, or
* SNAPSHOT_EXTERNAL with a valid file name and qcow2 format. */
qemuDomainObjEnterMonitorWithDriver(driver, vm);
@@ -10005,10 +10079,37 @@ qemuDomainSnapshotCreateDiskActive(virConnectPtr conn,
ret = qemuDomainSnapshotCreateSingleDiskActive(driver, vm,
&snap->def->disks[i],
vm->def->disks[i],
- persistDisk);
+ persistDisk, actions);
if (ret < 0)
break;
}
+ if (actions) {
+ if (ret == 0)
+ ret = qemuMonitorTransaction(priv->mon, actions);
+ if (ret < 0) {
+ /* Transaction failed; undo the changes to vm. */
+ bool need_unlink = !(flags & VIR_DOMAIN_SNAPSHOT_CREATE_REUSE_EXT);
+ while (--i >= 0) {
+ virDomainDiskDefPtr persistDisk = NULL;
+
+ if (snap->def->disks[i].snapshot == VIR_DOMAIN_DISK_SNAPSHOT_NO)
+ continue;
+ if (vm->newDef) {
+ int indx = virDomainDiskIndexByName(vm->newDef,
+ vm->def->disks[i]->dst,
+ false);
+ if (indx >= 0)
+ persistDisk = vm->newDef->disks[indx];
+ }
+
+ qemuDomainSnapshotUndoSingleDiskActive(driver, vm,
+
snap->def->dom->disks[i],
+ vm->def->disks[i],
+ persistDisk,
+ need_unlink);
+ }
+ }
+ }
qemuDomainObjExitMonitorWithDriver(driver, vm);
if (ret < 0)
goto cleanup;
@@ -10042,7 +10143,8 @@ cleanup:
}
}
- if (vm) {
+ if (vm && (ret == 0 ||
+ !qemuCapsGet(priv->qemuCaps, QEMU_CAPS_TRANSACTION))) {
if (virDomainSaveStatus(driver->caps, driver->stateDir, vm) < 0 ||
(persist &&
virDomainSaveConfig(driver->configDir, vm->newDef) < 0))
--
1.7.7.6