Re: [PATCH 3/4] qemu snapshot: use QMP snapshot-save/delete for internal snapshots

The usage of HMP commands are highly discouraged by qemu. Moreover, current snapshot creation routine does not provide flexibility in choosing target device for VM state snapshot. This patch makes use of QMP commands snapshot-save/delete and by default chooses first writable disk (if present) as target for VM state, NVRAM - otherwise. Signed-off-by: Nikolai Barybin <nikolai.barybin(a)virtuozzo.com&gt; --- src/qemu/qemu_snapshot.c | 158 ++++++++++++++++++++++++++++++++++++--- 1 file changed, 148 insertions(+), 10 deletions(-) diff --git a/src/qemu/qemu_snapshot.c b/src/qemu/qemu_snapshot.c index f5260c4a22..83949a9a27 100644 --- a/src/qemu/qemu_snapshot.c +++ b/src/qemu/qemu_snapshot.c @@ -308,6 +308,96 @@ qemuSnapshotCreateInactiveExternal(virQEMUDriver *driver, return ret; } +static int +qemuSnapshotActiveInternalGetWrdevListHelper(virDomainObj *vm, + char **wrdevs) +{ + size_t wrdevCount = 0; + size_t i = 0; + + for (i = 0; i < vm->def->ndisks; i++) { + virDomainDiskDef *disk = vm->def->disks[i]; + if (!disk->src->readonly) { + wrdevs[wrdevCount] = g_strdup(disk->src->nodenameformat); + wrdevCount++; + } + } + + if (wrdevCount == 0) { + if (vm->def->os.loader->nvram) { + wrdevs[0] = g_strdup(vm->def->os.loader->nvram->nodenameformat); + } else { + virReportError(VIR_ERR_INTERNAL_ERROR, "%s", + _("no writable device for internal snapshot creation/deletion")); + return -1; + } + } + + return 0; +} + + +static int +qemuSnapshotCreateActiveInternalDone(virDomainObj *vm) +{ + qemuBlockJobData *job = NULL; + qemuDomainObjPrivate *priv = vm->privateData; + + if (!(job = virHashLookup(priv->blockjobs, g_strdup_printf("snapsave%d", vm->def->id)))) { + virReportError(VIR_ERR_INTERNAL_ERROR, + _("failed to lookup blockjob 'snapsave%1$d'"), vm->def->id); + return -1; + } + + qemuBlockJobUpdate(vm, job, VIR_ASYNC_JOB_NONE); + if (job->state == VIR_DOMAIN_BLOCK_JOB_FAILED) { + virReportError(VIR_ERR_INTERNAL_ERROR, + _("snapshot-save job failed: %1$s"), NULLSTR(job->errmsg)); + return -1; + } + + return job->state == VIR_DOMAIN_BLOCK_JOB_COMPLETED ? 1 : 0; +} + + +static int +qemuSnapshotCreateActiveInternalStart(virDomainObj *vm, + const char *name) +{ + qemuBlockJobData *job = NULL; + g_autofree char** wrdevs = NULL; + int ret = -1; + int rc = 0; + + wrdevs = g_new0(char *, vm->def->ndisks + 1); + if (qemuSnapshotActiveInternalGetWrdevListHelper(vm, wrdevs) < 0) + return -1; + + if (!(job = qemuBlockJobDiskNew(vm, NULL, QEMU_BLOCKJOB_TYPE_SNAPSHOT_SAVE, + g_strdup_printf("snapsave%d", vm->def->id)))) { + virReportError(VIR_ERR_INTERNAL_ERROR, "%s", _("failed to create new blockjob")); + return -1; + } + + qemuBlockJobSyncBegin(job); + if (qemuDomainObjEnterMonitorAsync(vm, VIR_ASYNC_JOB_SNAPSHOT) < 0) { + ret = -1; + goto cleanup; + } + + rc = qemuMonitorSnapshotSave(qemuDomainGetMonitor(vm), job->name, + name, wrdevs[0], wrdevs); + qemuDomainObjExitMonitor(vm); + if (rc == 0) { + qemuBlockJobStarted(job, vm); + ret = 0; + } + + cleanup: + qemuBlockJobStartupFinalize(vm, job); + return ret; +} + /* The domain is expected to be locked and active. */ static int @@ -316,11 +406,11 @@ qemuSnapshotCreateActiveInternal(virQEMUDriver *driver, virDomainMomentObj *snap, unsigned int flags) { - qemuDomainObjPrivate *priv = vm->privateData; virObjectEvent *event = NULL; bool resume = false; virDomainSnapshotDef *snapdef = virDomainSnapshotObjGetDef(snap); int ret = -1; + int rv = 0; if (!qemuMigrationSrcIsAllowed(vm, false, VIR_ASYNC_JOB_SNAPSHOT, 0)) goto cleanup; @@ -342,15 +432,17 @@ qemuSnapshotCreateActiveInternal(virQEMUDriver *driver, } } - if (qemuDomainObjEnterMonitorAsync(vm, VIR_ASYNC_JOB_SNAPSHOT) < 0) { + if ((ret = qemuSnapshotCreateActiveInternalStart(vm, snap->def->name)) < 0) { resume = false; goto cleanup; } - ret = qemuMonitorCreateSnapshot(priv->mon, snap->def->name); - qemuDomainObjExitMonitor(vm); - if (ret < 0) - goto cleanup;