[libvirt] [PATCHv3 05/43] snapshot: only pass snapshot to qemu command line when reverting
Eric Blake
eblake at redhat.com
Wed Aug 24 15:22:22 UTC 2011
Changing the current vm, and writing that change to the file
system, all before a new qemu starts, is risky; it's hard to
roll back if starting the new qemu fails for some reason.
Instead of abusing vm->current_snapshot and making the command
line generator decide whether the current snapshot warrants
using -loadvm, it is better to just directly pass a snapshot all
the way through the call chain if it is to be loaded.
This frees up the last use of snapshot->def->active for qemu's
use, so the next patch can repurpose that field for tracking
which snapshot is current.
* src/qemu/qemu_command.c (qemuBuildCommandLine): Don't use active
field of snapshot.
* src/qemu/qemu_process.c (qemuProcessStart): Add a parameter.
* src/qemu/qemu_process.h (qemuProcessStart): Update prototype.
* src/qemu/qemu_migration.c (qemuMigrationPrepareAny): Update
callers.
* src/qemu/qemu_driver.c (qemudDomainCreate)
(qemuDomainSaveImageStartVM, qemuDomainObjStart)
(qemuDomainRevertToSnapshot): Likewise.
(qemuDomainSnapshotSetCurrentActive)
(qemuDomainSnapshotSetCurrentInactive): Delete unused functions.
---
src/qemu/qemu_command.c | 7 ++---
src/qemu/qemu_driver.c | 47 ++++----------------------------------------
src/qemu/qemu_migration.c | 2 +-
src/qemu/qemu_process.c | 10 +-------
src/qemu/qemu_process.h | 1 +
5 files changed, 12 insertions(+), 55 deletions(-)
diff --git a/src/qemu/qemu_command.c b/src/qemu/qemu_command.c
index 287ad8d..61fc2c7 100644
--- a/src/qemu/qemu_command.c
+++ b/src/qemu/qemu_command.c
@@ -2866,7 +2866,7 @@ qemuBuildCommandLine(virConnectPtr conn,
virBitmapPtr qemuCaps,
const char *migrateFrom,
int migrateFd,
- virDomainSnapshotObjPtr current_snapshot,
+ virDomainSnapshotObjPtr snapshot,
enum virVMOperationType vmop)
{
int i;
@@ -4782,9 +4782,8 @@ qemuBuildCommandLine(virConnectPtr conn,
}
}
- if (current_snapshot && current_snapshot->def->active)
- virCommandAddArgList(cmd, "-loadvm", current_snapshot->def->name,
- NULL);
+ if (snapshot)
+ virCommandAddArgList(cmd, "-loadvm", snapshot->def->name, NULL);
if (def->namespaceData) {
qemuDomainCmdlineDefPtr qemucmd;
diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
index d712bf2..c4183de 100644
--- a/src/qemu/qemu_driver.c
+++ b/src/qemu/qemu_driver.c
@@ -804,12 +804,6 @@ qemudShutdown(void) {
}
-static int qemuDomainSnapshotSetCurrentActive(virDomainObjPtr vm,
- char *snapshotDir);
-static int qemuDomainSnapshotSetCurrentInactive(virDomainObjPtr vm,
- char *snapshotDir);
-
-
static virDrvOpenStatus qemudOpen(virConnectPtr conn,
virConnectAuthPtr auth ATTRIBUTE_UNUSED,
unsigned int flags)
@@ -1297,7 +1291,7 @@ static virDomainPtr qemudDomainCreate(virConnectPtr conn, const char *xml,
if (qemuProcessStart(conn, driver, vm, NULL,
(flags & VIR_DOMAIN_START_PAUSED) != 0,
(flags & VIR_DOMAIN_START_AUTODESTROY) != 0,
- -1, NULL, VIR_VM_OP_CREATE) < 0) {
+ -1, NULL, NULL, VIR_VM_OP_CREATE) < 0) {
virDomainAuditStart(vm, "booted", false);
if (qemuDomainObjEndJob(driver, vm) > 0)
virDomainRemoveInactive(&driver->domains,
@@ -3920,7 +3914,7 @@ qemuDomainSaveImageStartVM(virConnectPtr conn,
/* Set the migration source and start it up. */
ret = qemuProcessStart(conn, driver, vm, "stdio", true,
- false, *fd, path, VIR_VM_OP_RESTORE);
+ false, *fd, path, NULL, VIR_VM_OP_RESTORE);
if (intermediatefd != -1) {
if (ret < 0) {
@@ -4462,7 +4456,7 @@ qemuDomainObjStart(virConnectPtr conn,
}
ret = qemuProcessStart(conn, driver, vm, NULL, start_paused,
- autodestroy, -1, NULL, VIR_VM_OP_CREATE);
+ autodestroy, -1, NULL, NULL, VIR_VM_OP_CREATE);
virDomainAuditStart(vm, "booted", ret >= 0);
if (ret >= 0) {
virDomainEventPtr event =
@@ -8318,32 +8312,6 @@ cleanup:
return ret;
}
-static int qemuDomainSnapshotSetCurrentActive(virDomainObjPtr vm,
- char *snapshotDir)
-{
- if (vm->current_snapshot) {
- vm->current_snapshot->def->active = 1;
-
- return qemuDomainSnapshotWriteMetadata(vm, vm->current_snapshot,
- snapshotDir);
- }
-
- return 0;
-}
-
-static int qemuDomainSnapshotSetCurrentInactive(virDomainObjPtr vm,
- char *snapshotDir)
-{
- if (vm->current_snapshot) {
- vm->current_snapshot->def->active = 0;
-
- return qemuDomainSnapshotWriteMetadata(vm, vm->current_snapshot,
- snapshotDir);
- }
-
- return 0;
-}
-
static int qemuDomainSnapshotIsAllowed(virDomainObjPtr vm)
{
@@ -8861,17 +8829,12 @@ static int qemuDomainRevertToSnapshot(virDomainSnapshotPtr snapshot,
goto endjob;
}
} else {
- if (qemuDomainSnapshotSetCurrentActive(vm, driver->snapshotDir) < 0)
- goto endjob;
-
rc = qemuProcessStart(snapshot->domain->conn, driver, vm, NULL,
- true, false, -1, NULL, VIR_VM_OP_CREATE);
+ true, false, -1, NULL, vm->current_snapshot,
+ VIR_VM_OP_CREATE);
virDomainAuditStart(vm, "from-snapshot", rc >= 0);
if (rc < 0)
goto endjob;
- if (qemuDomainSnapshotSetCurrentInactive(vm,
- driver->snapshotDir) < 0)
- goto endjob;
}
/* Touch up domain state. */
diff --git a/src/qemu/qemu_migration.c b/src/qemu/qemu_migration.c
index a84faf6..b88d9c0 100644
--- a/src/qemu/qemu_migration.c
+++ b/src/qemu/qemu_migration.c
@@ -1034,7 +1034,7 @@ qemuMigrationPrepareAny(struct qemud_driver *driver,
* -incoming $migrateFrom
*/
if (qemuProcessStart(dconn, driver, vm, migrateFrom, true,
- true, dataFD[0], NULL,
+ true, dataFD[0], NULL, NULL,
VIR_VM_OP_MIGRATE_IN_START) < 0) {
virDomainAuditStart(vm, "migrated", false);
/* Note that we don't set an error here because qemuProcessStart
diff --git a/src/qemu/qemu_process.c b/src/qemu/qemu_process.c
index 616c8e2..f691bbb 100644
--- a/src/qemu/qemu_process.c
+++ b/src/qemu/qemu_process.c
@@ -2614,6 +2614,7 @@ int qemuProcessStart(virConnectPtr conn,
bool autodestroy,
int stdin_fd,
const char *stdin_path,
+ virDomainSnapshotObjPtr snapshot,
enum virVMOperationType vmop)
{
int ret;
@@ -2816,16 +2817,9 @@ int qemuProcessStart(virConnectPtr conn,
VIR_DEBUG("Building emulator command line");
if (!(cmd = qemuBuildCommandLine(conn, driver, vm->def, priv->monConfig,
priv->monJSON != 0, priv->qemuCaps,
- migrateFrom, stdin_fd,
- vm->current_snapshot, vmop)))
+ migrateFrom, stdin_fd, snapshot, vmop)))
goto cleanup;
-#if 0
- /* XXX */
- if (qemuDomainSnapshotSetCurrentInactive(vm, driver->snapshotDir) < 0)
- goto cleanup;
-#endif
-
/* now that we know it is about to start call the hook if present */
if (virHookPresent(VIR_HOOK_DRIVER_QEMU)) {
char *xml = virDomainDefFormat(vm->def, 0);
diff --git a/src/qemu/qemu_process.h b/src/qemu/qemu_process.h
index e9b910d..96ba3f3 100644
--- a/src/qemu/qemu_process.h
+++ b/src/qemu/qemu_process.h
@@ -52,6 +52,7 @@ int qemuProcessStart(virConnectPtr conn,
bool autodestroy,
int stdin_fd,
const char *stdin_path,
+ virDomainSnapshotObjPtr snapshot,
enum virVMOperationType vmop);
void qemuProcessStop(struct qemud_driver *driver,
--
1.7.4.4
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