[libvirt] [PATCH v4 19/20] backup: Wire up qemu full pull backup commands over QMP
Eric Blake
eblake at redhat.com
Wed Feb 6 19:18:17 UTC 2019
Time to actually issue the QMP transactions that start and
stop backup commands (for now, just pull mode, not push).
Starting a job has to kick off several pre-req steps, then
a transaction, and additionally spawn an NBD server for pull
mode; ending a job as well as failing partway through
beginning a job has to unwind the earlier steps. Implementing
incremental pull and checkpoint creation is deferred to the
next patch.
Signed-off-by: Eric Blake <eblake at redhat.com>
---
src/qemu/qemu_domain.c | 18 ++-
src/qemu/qemu_driver.c | 282 ++++++++++++++++++++++++++++++++++++++--
src/qemu/qemu_process.c | 7 +
3 files changed, 293 insertions(+), 14 deletions(-)
diff --git a/src/qemu/qemu_domain.c b/src/qemu/qemu_domain.c
index 1385df962d..6e684782fa 100644
--- a/src/qemu/qemu_domain.c
+++ b/src/qemu/qemu_domain.c
@@ -2695,16 +2695,24 @@ qemuDomainObjPrivateXMLParseBlockjobs(virQEMUDriverPtr driver,
char *active;
int tmp;
int ret = -1;
+ size_t i;
if ((active = virXPathString("string(./blockjobs/@active)", ctxt)) &&
(tmp = virTristateBoolTypeFromString(active)) > 0)
priv->reconnectBlockjobs = tmp;
- if ((node = virXPathNode("./domainbackup", ctxt)) &&
- !(priv->backup = virDomainBackupDefParseNode(ctxt->doc, node,
- driver->xmlopt,
- VIR_DOMAIN_BACKUP_PARSE_INTERNAL)))
- goto cleanup;
+ if ((node = virXPathNode("./domainbackup", ctxt))) {
+ if (!(priv->backup = virDomainBackupDefParseNode(ctxt->doc, node,
+ driver->xmlopt,
+ VIR_DOMAIN_BACKUP_PARSE_INTERNAL)))
+ goto cleanup;
+ /* The backup job is only stored in XML if backupBegin
+ * succeeded at exporting the disk, so no need to store disk
+ * state when we can just force-reset it to a known-good
+ * value. */
+ for (i = 0; i < priv->backup->ndisks; i++)
+ priv->backup->disks[i].state = VIR_DOMAIN_BACKUP_DISK_STATE_EXPORT;
+ }
ret = 0;
cleanup:
diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
index 4e9273ef9c..267b6e5c4d 100644
--- a/src/qemu/qemu_driver.c
+++ b/src/qemu/qemu_driver.c
@@ -17771,8 +17771,80 @@ qemuDomainCheckpointDelete(virDomainCheckpointPtr checkpoint,
return ret;
}
-static int qemuDomainBackupBegin(virDomainPtr domain, const char *diskXml,
- const char *checkpointXml, unsigned int flags)
+static int
+qemuDomainBackupPrepare(virQEMUDriverPtr driver, virDomainObjPtr vm,
+ virDomainBackupDefPtr def)
+{
+ int ret = -1;
+ size_t i;
+
+ if (qemuBlockNodeNamesDetect(driver, vm, QEMU_ASYNC_JOB_NONE) < 0)
+ goto cleanup;
+ for (i = 0; i < def->ndisks; i++) {
+ virDomainBackupDiskDef *disk = &def->disks[i];
+ virStorageSourcePtr src = vm->def->disks[disk->idx]->src;
+
+ if (!disk->store)
+ continue;
+ if (virAsprintf(&disk->store->nodeformat, "tmp-%s", disk->name) < 0)
+ goto cleanup;
+ if (!disk->store->format)
+ disk->store->format = VIR_STORAGE_FILE_QCOW2;
+ if (def->incremental) {
+ if (src->format != VIR_STORAGE_FILE_QCOW2) {
+ virReportError(VIR_ERR_OPERATION_UNSUPPORTED,
+ _("incremental backup of %s requires qcow2"),
+ disk->name);
+ goto cleanup;
+ }
+ }
+ }
+ ret = 0;
+ cleanup:
+ return ret;
+}
+
+/* Called while monitor lock is held. Best-effort cleanup. */
+static int
+qemuDomainBackupDiskCleanup(virQEMUDriverPtr driver, virDomainObjPtr vm,
+ virDomainBackupDiskDef *disk, bool incremental)
+{
+ qemuDomainObjPrivatePtr priv = vm->privateData;
+ const char *node = vm->def->disks[disk->idx]->src->nodeformat;
+ int ret = 0;
+
+ if (!disk->store)
+ return 0;
+ if (disk->state >= VIR_DOMAIN_BACKUP_DISK_STATE_EXPORT) {
+ /* No real need to use nbd-server-remove, since we will
+ * shortly be calling nbd-server-stop. */
+ }
+ if (incremental && disk->state >= VIR_DOMAIN_BACKUP_DISK_STATE_BITMAP &&
+ qemuMonitorDeleteBitmap(priv->mon, node, disk->store->nodeformat) < 0) {
+ VIR_WARN("Unable to remove temp bitmap for disk %s after backup",
+ disk->name);
+ ret = -1;
+ }
+ if (disk->state >= VIR_DOMAIN_BACKUP_DISK_STATE_READY &&
+ qemuMonitorBlockdevDel(priv->mon, disk->store->nodeformat) < 0) {
+ VIR_WARN("Unable to remove temp disk %s after backup",
+ disk->name);
+ ret = -1;
+ }
+ if (disk->state >= VIR_DOMAIN_BACKUP_DISK_STATE_LABEL)
+ qemuDomainDiskChainElementRevoke(driver, vm, disk->store);
+ if (disk->state >= VIR_DOMAIN_BACKUP_DISK_STATE_CREATED &&
+ disk->store->detected && unlink(disk->store->path) < 0) {
+ VIR_WARN("Unable to unlink temp disk %s after backup",
+ disk->store->path);
+ ret = -1;
+ }
+ return ret;
+}
+
+static int
+qemuDomainBackupBegin(virDomainPtr domain, const char *diskXml,
+ const char *checkpointXml, unsigned int flags)
{
virQEMUDriverPtr driver = domain->conn->privateData;
virDomainObjPtr vm = NULL;
@@ -17781,8 +17853,14 @@ static int qemuDomainBackupBegin(virDomainPtr domain, const char *diskXml,
virCapsPtr caps = NULL;
qemuDomainObjPrivatePtr priv;
int ret = -1;
+ virJSONValuePtr json = NULL;
+ bool job_started = false;
+ bool nbd_running = false;
+ size_t i;
struct timeval tv;
char *suffix = NULL;
+ virCommandPtr cmd = NULL;
+ const char *qemuImgPath;
virCheckFlags(VIR_DOMAIN_BACKUP_BEGIN_NO_METADATA, -1);
/* TODO: VIR_DOMAIN_BACKUP_BEGIN_QUIESCE */
@@ -17803,6 +17881,7 @@ static int qemuDomainBackupBegin(virDomainPtr domain, const char *diskXml,
if (!(vm = qemuDomObjFromDomain(domain)))
goto cleanup;
+ priv = vm->privateData;
cfg = virQEMUDriverGetConfig(driver);
if (virDomainBackupBeginEnsureACL(domain->conn, vm->def) < 0)
@@ -17825,25 +17904,115 @@ static int qemuDomainBackupBegin(virDomainPtr domain, const char *diskXml,
if (!(def = virDomainBackupDefParseString(diskXml, driver->xmlopt, 0)))
goto cleanup;
+ if (def->type == VIR_DOMAIN_BACKUP_TYPE_PULL) {
+ if (!virQEMUCapsGet(priv->qemuCaps, QEMU_CAPS_NBD_BITMAP)) {
+ virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s",
+ _("qemu binary lacks pull-mode backup support"));
+ goto cleanup;
+ }
+ if (!def->server ||
+ def->server->transport != VIR_STORAGE_NET_HOST_TRANS_TCP) {
+ virReportError(VIR_ERR_OPERATION_UNSUPPORTED, "%s",
+ _("<domainbackup> must specify TCP server for now"));
+ goto cleanup;
+ }
+ } else {
+ virReportError(VIR_ERR_OPERATION_UNSUPPORTED, "%s",
+ _("push mode backups not supported yet"));
+ goto cleanup;
+ }
+ if (def->incremental) {
+ if (!virQEMUCapsGet(priv->qemuCaps, QEMU_CAPS_BITMAP_MERGE)) {
+ virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s",
+ _("qemu binary lacks persistent bitmaps support"));
+ goto cleanup;
+ }
+ virReportError(VIR_ERR_OPERATION_UNSUPPORTED, "%s",
+ _("cannot create incremental backups yet"));
+ goto cleanup;
+ }
+
+ if (!(qemuImgPath = qemuFindQemuImgBinary(driver)))
+ goto cleanup;
+
/* We are going to modify the domain below. */
if (qemuDomainObjBeginJob(driver, vm, QEMU_JOB_MODIFY) < 0)
goto cleanup;
- priv = vm->privateData;
if (priv->backup) {
virReportError(VIR_ERR_OPERATION_INVALID,
"%s", _("another backup job is already running"));
goto endjob;
}
- if (virDomainBackupAlignDisks(def, vm->def, suffix) < 0)
+ if (virDomainBackupAlignDisks(def, vm->def, suffix) < 0 ||
+ qemuDomainBackupPrepare(driver, vm, def) < 0)
goto endjob;
/* actually start the checkpoint. 2x2 array of push/pull, full/incr,
plus additional tweak if checkpoint requested */
- /* TODO: issue QMP commands:
- - pull: nbd-server-start with <server> from user (or autogenerate server)
- - push/pull: blockdev-add per <disk>
+ qemuDomainObjEnterMonitor(driver, vm);
+ /* - push/pull: blockdev-add per <disk> */
+ for (i = 0; i < def->ndisks; i++) {
+ virDomainBackupDiskDef *disk = &def->disks[i];
+ virJSONValuePtr file;
+ virStorageSourcePtr src = vm->def->disks[disk->idx]->src;
+ const char *node = src->nodeformat;
+
+ if (!disk->store)
+ continue;
+ if (qemuDomainStorageFileInit(driver, vm, disk->store, src) < 0)
+ goto endmon;
+ if (disk->store->detected) {
+ if (virStorageFileCreate(disk->store) < 0) {
+ virReportSystemError(errno,
+ _("failed to create image file '%s'"),
+ NULLSTR(disk->store->path));
+ goto endmon;
+ }
+ disk->state = VIR_DOMAIN_BACKUP_DISK_STATE_CREATED;
+ }
+ if (qemuDomainDiskChainElementPrepare(driver, vm, disk->store, false,
+ true) < 0)
+ goto endmon;
+ disk->state = VIR_DOMAIN_BACKUP_DISK_STATE_LABEL;
+ /* Force initialization of scratch file to new qcow2 */
+ if (!(cmd = virCommandNewArgList(qemuImgPath,
+ "create",
+ "-f",
+ virStorageFileFormatTypeToString(disk->store->format),
+ "-o",
+ NULL)))
+ goto endmon;
+ virCommandAddArgFormat(cmd, "backing_file=%s,backing_fmt=%s",
+ src->path,
+ virStorageFileFormatTypeToString(src->format));
+ virCommandAddArg(cmd, disk->store->path);
+ if (virCommandRun(cmd, NULL) < 0)
+ goto endmon;
+ virCommandFree(cmd);
+ cmd = NULL;
+
+ if (virJSONValueObjectCreate(&file,
+ "s:driver", "file",
+ "s:filename", disk->store->path,
+ NULL) < 0)
+ goto endmon;
+ if (virJSONValueObjectCreate(&json,
+ "s:driver", virStorageFileFormatTypeToString(disk->store->format),
+ "s:node-name", disk->store->nodeformat,
+ "a:file", &file,
+ "s:backing", node, NULL) < 0) {
+ virJSONValueFree(file);
+ goto endmon;
+ }
+ if (qemuMonitorBlockdevAdd(priv->mon, json) < 0)
+ goto endmon;
+ json = NULL;
+ disk->state = VIR_DOMAIN_BACKUP_DISK_STATE_READY;
+ }
+
+ /* TODO:
- incr: bitmap-add of tmp, bitmap-merge per <disk>
- transaction, containing:
- push+full: blockdev-backup sync:full
@@ -17851,8 +18020,78 @@ static int qemuDomainBackupBegin(virDomainPtr domain, const char *diskXml,
- pull+full: blockdev-backup sync:none
- pull+incr: blockdev-backup sync:none, bitmap-disable of tmp
- if checkpoint: bitmap-disable of old, bitmap-add of new
+ */
+ if (!(json = virJSONValueNewArray()))
+ goto endmon;
+ for (i = 0; i < def->ndisks; i++) {
+ virDomainBackupDiskDef *disk = &def->disks[i];
+ virStorageSourcePtr src = vm->def->disks[disk->idx]->src;
+
+ if (!disk->store)
+ continue;
+ if (qemuMonitorJSONTransactionAdd(json,
+ "blockdev-backup",
+ "s:device", src->nodeformat,
+ "s:target", disk->store->nodeformat,
+ "s:sync", "none",
+ "s:job-id", disk->store->nodeformat,
+ NULL) < 0)
+ goto endmon;
+ }
+ if (qemuMonitorTransaction(priv->mon, &json) < 0)
+ goto endmon;
+ job_started = true;
+
+ /*
+ - pull: nbd-server-start with <server> from user (or autogenerate server)
- pull: nbd-server-add per <disk>, including bitmap for incr
*/
+ if (def->type == VIR_DOMAIN_BACKUP_TYPE_PULL) {
+ if (qemuMonitorNBDServerStart(priv->mon, def->server->name,
+ def->server->port, NULL) < 0)
+ goto endmon;
+ nbd_running = true;
+ for (i = 0; i < def->ndisks; i++) {
+ virDomainBackupDiskDef *disk = &def->disks[i];
+
+ if (!disk->store)
+ continue;
+ if (qemuMonitorNBDServerAdd(priv->mon, disk->store->nodeformat,
+ disk->name, false,
+ def->incremental ? disk->name :
+ NULL) < 0)
+ goto endmon;
+ disk->state = VIR_DOMAIN_BACKUP_DISK_STATE_EXPORT;
+ }
+ }
+
+ ret = 0;
+ endmon:
+ /* Best effort cleanup if we fail partway through */
+ if (ret < 0) {
+ virErrorPtr save_err = virSaveLastError();
+
+ if (nbd_running &&
+ qemuMonitorNBDServerStop(priv->mon) < 0)
+ VIR_WARN("Unable to stop NBD server on vm %s after backup job",
+ vm->def->name);
+ for (i = 0; i < def->ndisks; i++) {
+ virDomainBackupDiskDef *disk = &def->disks[i];
+
+ if (job_started &&
+ qemuMonitorBlockJobCancel(priv->mon,
+ disk->store->nodeformat) < 0)
+ VIR_WARN("Unable to stop backup job %s on vm %s after failure",
+ disk->store->nodeformat, vm->def->name);
+ qemuDomainBackupDiskCleanup(driver, vm, disk, !!def->incremental);
+ }
+ virSetError(save_err);
+ virFreeError(save_err);
+ }
+ if (qemuDomainObjExitMonitor(driver, vm) < 0)
+ ret = -1;
+ if (ret < 0)
+ goto endjob;
VIR_STEAL_PTR(priv->backup, def);
ret = priv->backup->id = 1; /* Hard-coded job id for now */
@@ -17865,7 +18104,9 @@ static int qemuDomainBackupBegin(virDomainPtr domain, const char *diskXml,
qemuDomainObjEndJob(driver, vm);
cleanup:
+ virCommandFree(cmd);
VIR_FREE(suffix);
+ virJSONValueFree(json);
virDomainObjEndAPI(&vm);
virDomainBackupDefFree(def);
virObjectUnref(caps);
@@ -17915,6 +18156,8 @@ static int qemuDomainBackupEnd(virDomainPtr domain, int id, unsigned int flags)
virDomainBackupDefPtr backup = NULL;
qemuDomainObjPrivatePtr priv;
bool want_abort = flags & VIR_DOMAIN_BACKUP_END_ABORT;
+ virDomainBackupDefPtr def;
+ size_t i;
virCheckFlags(VIR_DOMAIN_BACKUP_END_ABORT, -1);
@@ -17935,9 +18178,27 @@ static int qemuDomainBackupEnd(virDomainPtr domain, int id, unsigned int flags)
if (priv->backup->type != VIR_DOMAIN_BACKUP_TYPE_PUSH)
want_abort = false;
+ def = priv->backup;
+
+ /* We are going to modify the domain below. */
+ if (qemuDomainObjBeginJob(driver, vm, QEMU_JOB_MODIFY) < 0)
+ goto cleanup;
+
+ qemuDomainObjEnterMonitor(driver, vm);
+ if (def->type == VIR_DOMAIN_BACKUP_TYPE_PULL)
+ ret = qemuMonitorNBDServerStop(priv->mon);
+ for (i = 0; i < def->ndisks; i++) {
+ if (qemuMonitorBlockJobCancel(priv->mon,
+ def->disks[i].store->nodeformat) < 0 ||
+ qemuDomainBackupDiskCleanup(driver, vm, &def->disks[i],
+ !!def->incremental) < 0)
+ ret = -1;
+ }
+ if (qemuDomainObjExitMonitor(driver, vm) < 0 || ret < 0) {
+ ret = -1;
+ goto endjob;
+ }
- /* TODO: QMP commands to actually cancel the pending job, and on
- * pull, also tear down the NBD server */
VIR_STEAL_PTR(backup, priv->backup);
if (virDomainSaveStatus(driver->xmlopt, cfg->stateDir, vm,
driver->caps) < 0)
@@ -17946,6 +18207,9 @@ static int qemuDomainBackupEnd(virDomainPtr domain, int id, unsigned int flags)
ret = want_abort ? 0 : 1;
+ endjob:
+ qemuDomainObjEndJob(driver, vm);
+
cleanup:
virDomainBackupDefFree(backup);
virDomainObjEndAPI(&vm);
diff --git a/src/qemu/qemu_process.c b/src/qemu/qemu_process.c
index 0583eb03f2..4f6061ed93 100644
--- a/src/qemu/qemu_process.c
+++ b/src/qemu/qemu_process.c
@@ -925,6 +925,7 @@ qemuProcessHandleBlockJob(qemuMonitorPtr mon ATTRIBUTE_UNUSED,
void *opaque)
{
virQEMUDriverPtr driver = opaque;
+ qemuDomainObjPrivatePtr priv;
struct qemuProcessEvent *processEvent = NULL;
virDomainDiskDefPtr disk;
qemuBlockJobDataPtr job = NULL;
@@ -935,6 +936,12 @@ qemuProcessHandleBlockJob(qemuMonitorPtr mon ATTRIBUTE_UNUSED,
VIR_DEBUG("Block job for device %s (domain: %p,%s) type %d status %d",
diskAlias, vm, vm->def->name, type, status);
+ priv = vm->privateData;
+ if (type == VIR_DOMAIN_BLOCK_JOB_TYPE_BACKUP && priv->backup) {
+ /* Event for canceling a pull-mode backup is side-effect that
+ * should not be forwarded on to user */
+ goto cleanup;
+ }
if (!(disk = qemuProcessFindDomainDiskByAliasOrQOM(vm, diskAlias, NULL)))
goto cleanup;
--
2.20.1
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