[PATCH v2 14/15] qemu: migration: Migrate block dirty bitmaps corresponding to checkpoints
Peter Krempa
pkrempa at redhat.com
Fri Feb 19 11:58:26 UTC 2021
Preserve block dirty bitmaps after migration with
QEMU_MONITOR_MIGRATE_NON_SHARED_(DISK|INC).
This patch implements functions which offer the bitmaps to the
destination, check for eligibility on destination and then configure
source for the migration.
Signed-off-by: Peter Krempa <pkrempa at redhat.com>
---
src/qemu/qemu_migration.c | 333 +++++++++++++++++++++++++++++++++++++-
1 file changed, 331 insertions(+), 2 deletions(-)
diff --git a/src/qemu/qemu_migration.c b/src/qemu/qemu_migration.c
index 4e69fab384..08f60c6db3 100644
--- a/src/qemu/qemu_migration.c
+++ b/src/qemu/qemu_migration.c
@@ -2205,6 +2205,91 @@ qemuMigrationSrcCleanup(virDomainObjPtr vm,
}
+/**
+ * qemuMigrationSrcBeginPhaseBlockDirtyBitmaps:
+ * @mig: migration cookie struct
+ * @vm: domain object
+ * @migrate_disks: disks which are being migrated
+ * @nmigrage_disks: number of @migrate_disks
+ *
+ * Enumerates block dirty bitmaps on disks which will undergo storage migration
+ * and fills them into @mig to be offered to the destination.
+ */
+static int
+qemuMigrationSrcBeginPhaseBlockDirtyBitmaps(qemuMigrationCookiePtr mig,
+ virDomainObjPtr vm,
+ const char **migrate_disks,
+ size_t nmigrate_disks)
+
+{
+ GSList *disks = NULL;
+ qemuDomainObjPrivatePtr priv = vm->privateData;
+ size_t i;
+
+ g_autoptr(GHashTable) blockNamedNodeData = NULL;
+
+ if (!(blockNamedNodeData = qemuBlockGetNamedNodeData(vm, priv->job.asyncJob)))
+ return -1;
+
+ for (i = 0; i < vm->def->ndisks; i++) {
+ qemuMigrationBlockDirtyBitmapsDiskPtr disk;
+ GSList *bitmaps = NULL;
+ virDomainDiskDefPtr diskdef = vm->def->disks[i];
+ qemuBlockNamedNodeDataPtr nodedata = virHashLookup(blockNamedNodeData, diskdef->src->nodeformat);
+ size_t j;
+
+ if (!nodedata)
+ continue;
+
+ if (migrate_disks) {
+ bool migrating = false;
+
+ for (j = 0; j < nmigrate_disks; j++) {
+ if (STREQ(migrate_disks[j], diskdef->dst)) {
+ migrating = true;
+ break;
+ }
+ }
+
+ if (!migrating)
+ continue;
+ }
+
+ for (j = 0; j < nodedata->nbitmaps; j++) {
+ qemuMigrationBlockDirtyBitmapsDiskBitmapPtr bitmap;
+
+ if (!qemuBlockBitmapChainIsValid(diskdef->src,
+ nodedata->bitmaps[j]->name,
+ blockNamedNodeData))
+ continue;
+
+ bitmap = g_new0(qemuMigrationBlockDirtyBitmapsDiskBitmap, 1);
+ bitmap->bitmapname = g_strdup(nodedata->bitmaps[j]->name);
+ bitmap->alias = g_strdup_printf("libvirt-%s-%s",
+ diskdef->dst,
+ nodedata->bitmaps[j]->name);
+ bitmaps = g_slist_prepend(bitmaps, bitmap);
+ }
+
+ if (!bitmaps)
+ continue;
+
+ disk = g_new0(qemuMigrationBlockDirtyBitmapsDisk, 1);
+ disk->target = g_strdup(diskdef->dst);
+ disk->bitmaps = bitmaps;
+ disks = g_slist_prepend(disks, disk);
+ }
+
+ if (!disks)
+ return 0;
+
+ mig->blockDirtyBitmaps = disks;
+ mig->flags |= QEMU_MIGRATION_COOKIE_BLOCK_DIRTY_BITMAPS;
+
+ return 0;
+}
+
+
/* The caller is supposed to lock the vm and start a migration job. */
static char *
qemuMigrationSrcBeginPhase(virQEMUDriverPtr driver,
@@ -2317,6 +2402,12 @@ qemuMigrationSrcBeginPhase(virQEMUDriverPtr driver,
if (!(mig = qemuMigrationCookieNew(vm->def, priv->origname)))
return NULL;
+ if (cookieFlags & QEMU_MIGRATION_COOKIE_NBD &&
+ virQEMUCapsGet(priv->qemuCaps, QEMU_CAPS_MIGRATION_PARAM_BLOCK_BITMAP_MAPPING) &&
+ qemuMigrationSrcBeginPhaseBlockDirtyBitmaps(mig, vm, migrate_disks,
+ nmigrate_disks) < 0)
+ return NULL;
+
if (qemuMigrationCookieFormat(mig, driver, vm,
QEMU_MIGRATION_SOURCE,
cookieout, cookieoutlen,
@@ -2530,6 +2621,92 @@ qemuMigrationDstPrepare(virDomainObjPtr vm,
migrateFrom, fd, NULL);
}
+
+/**
+ * qemuMigrationDstPrepareAnyBlockDirtyBitmaps:
+ * @vm: domain object
+ * @mig: migration cookie
+ * @migParams: migration parameters
+ * @flags: migration flags
+ *
+ * Checks whether block dirty bitmaps offered by the migration source are
+ * to be migrated (e.g. they don't exist, the destination is compatible etc)
+ * and sets up destination qemu for migrating the bitmaps as well as updates the
+ * list of eligible bitmaps in the migration cookie to be sent back to the
+ * source.
+ */
+static int
+qemuMigrationDstPrepareAnyBlockDirtyBitmaps(virDomainObjPtr vm,
+ qemuMigrationCookiePtr mig,
+ qemuMigrationParamsPtr migParams,
+ unsigned int flags)
+{
+ qemuDomainObjPrivatePtr priv = vm->privateData;
+ g_autoptr(virJSONValue) mapping = NULL;
+ g_autoptr(GHashTable) blockNamedNodeData = NULL;
+ GSList *nextdisk;
+
+ if (!mig->nbd ||
+ !mig->blockDirtyBitmaps ||
+ !(flags & (VIR_MIGRATE_NON_SHARED_DISK | VIR_MIGRATE_NON_SHARED_INC)) ||
+ !virQEMUCapsGet(priv->qemuCaps, QEMU_CAPS_MIGRATION_PARAM_BLOCK_BITMAP_MAPPING))
+ return 0;
+
+ if (qemuMigrationCookieBlockDirtyBitmapsMatchDisks(vm->def, mig->blockDirtyBitmaps) < 0)
+ return -1;
+
+ if (!(blockNamedNodeData = qemuBlockGetNamedNodeData(vm, QEMU_ASYNC_JOB_MIGRATION_IN)))
+ return -1;
+
+ for (nextdisk = mig->blockDirtyBitmaps; nextdisk; nextdisk = nextdisk->next) {
+ qemuMigrationBlockDirtyBitmapsDiskPtr disk = nextdisk->data;
+ qemuBlockNamedNodeDataPtr nodedata;
+ GSList *nextbitmap;
+
+ if (!(nodedata = virHashLookup(blockNamedNodeData, disk->nodename))) {
+ virReportError(VIR_ERR_INTERNAL_ERROR,
+ _("failed to find data for block node '%s'"),
+ disk->nodename);
+ return -1;
+ }
+
+ /* Bitmaps can only be migrated to qcow2 v3+ */
+ if (disk->disk->src->format != VIR_STORAGE_FILE_QCOW2 ||
+ nodedata->qcow2v2) {
+ disk->skip = true;
+ continue;
+ }
+
+ for (nextbitmap = disk->bitmaps; nextbitmap; nextbitmap = nextbitmap->next) {
+ qemuMigrationBlockDirtyBitmapsDiskBitmapPtr bitmap = nextbitmap->data;
+ size_t k;
+
+ /* don't migrate into existing bitmaps */
+ for (k = 0; k < nodedata->nbitmaps; k++) {
+ if (STREQ(bitmap->bitmapname, nodedata->bitmaps[k]->name)) {
+ bitmap->skip = true;
+ break;
+ }
+ }
+
+ if (bitmap->skip)
+ continue;
+ }
+ }
+
+ if (qemuMigrationCookieBlockDirtyBitmapsToParams(mig->blockDirtyBitmaps,
+ &mapping) < 0)
+ return -1;
+
+ if (!mapping)
+ return 0;
+
+ qemuMigrationParamsSetBlockDirtyBitmapMapping(migParams, &mapping);
+ mig->flags |= QEMU_MIGRATION_COOKIE_BLOCK_DIRTY_BITMAPS;
+ return 0;
+}
+
+
static int
qemuMigrationDstPrepareAny(virQEMUDriverPtr driver,
virConnectPtr dconn,
@@ -2679,7 +2856,8 @@ qemuMigrationDstPrepareAny(virQEMUDriverPtr driver,
QEMU_MIGRATION_COOKIE_CPU_HOTPLUG |
QEMU_MIGRATION_COOKIE_CPU |
QEMU_MIGRATION_COOKIE_ALLOW_REBOOT |
- QEMU_MIGRATION_COOKIE_CAPS)))
+ QEMU_MIGRATION_COOKIE_CAPS |
+ QEMU_MIGRATION_COOKIE_BLOCK_DIRTY_BITMAPS)))
goto cleanup;
if (!(vm = virDomainObjListAdd(driver->domains, *def,
@@ -2772,6 +2950,9 @@ qemuMigrationDstPrepareAny(virQEMUDriverPtr driver,
goto stopjob;
}
+ if (qemuMigrationDstPrepareAnyBlockDirtyBitmaps(vm, mig, migParams, flags) < 0)
+ goto stopjob;
+
if (qemuMigrationParamsCheck(driver, vm, QEMU_ASYNC_JOB_MIGRATION_IN,
migParams, mig->caps->automatic) < 0)
goto stopjob;
@@ -3654,6 +3835,145 @@ qemuMigrationSetDBusVMState(virQEMUDriverPtr driver,
}
+/**
+ * qemuMigrationSrcRunPrepareBlockDirtyBitmapsMerge:
+ * @vm: domain object
+ * @mig: migration cookie
+ *
+ * When migrating full disks, which means that the backing chain of the disk
+ * will be squashed into a single image we need to calculate bitmaps
+ * corresponding to the checkpoints which express the same set of changes
+ * for migration.
+ *
+ * This function prepares temporary bitmaps and corresponding merges, updates
+ * the data so that the temporary bitmaps are used and registers the temporary
+ * bitmaps for deletion on failed migration.
+ */
+static int
+qemuMigrationSrcRunPrepareBlockDirtyBitmapsMerge(virDomainObjPtr vm,
+ qemuMigrationCookiePtr mig)
+{
+ g_autoslist(qemuDomainJobPrivateMigrateTempBitmap) tmpbitmaps = NULL;
+ qemuDomainObjPrivatePtr priv = vm->privateData;
+ qemuDomainJobPrivatePtr jobPriv = priv->job.privateData;
+ virQEMUDriverPtr driver = priv->driver;
+ g_autoptr(virJSONValue) actions = virJSONValueNewArray();
+ g_autoptr(GHashTable) blockNamedNodeData = NULL;
+ GSList *nextdisk;
+ int rc;
+
+ if (!(blockNamedNodeData = qemuBlockGetNamedNodeData(vm, QEMU_ASYNC_JOB_MIGRATION_OUT)))
+ return -1;
+
+ for (nextdisk = mig->blockDirtyBitmaps; nextdisk; nextdisk = nextdisk->next) {
+ qemuMigrationBlockDirtyBitmapsDiskPtr disk = nextdisk->data;
+ GSList *nextbitmap;
+
+ /* if a disk doesn't have a backing chain we don't need the code below */
+ if (!virStorageSourceHasBacking(disk->disk->src))
+ continue;
+
+ for (nextbitmap = disk->bitmaps; nextbitmap; nextbitmap = nextbitmap->next) {
+ qemuMigrationBlockDirtyBitmapsDiskBitmapPtr bitmap = nextbitmap->data;
+ qemuDomainJobPrivateMigrateTempBitmapPtr tmpbmp;
+ virStorageSourcePtr n;
+ unsigned long long granularity = 0;
+ g_autoptr(virJSONValue) merge = virJSONValueNewArray();
+
+ for (n = disk->disk->src; virStorageSourceIsBacking(n); n = n->backingStore) {
+ qemuBlockNamedNodeDataBitmapPtr b;
+
+ if (!(b = qemuBlockNamedNodeDataGetBitmapByName(blockNamedNodeData, n,
+ bitmap->bitmapname)))
+ break;
+
+ if (granularity == 0)
+ granularity = b->granularity;
+
+ if (qemuMonitorTransactionBitmapMergeSourceAddBitmap(merge,
+ n->nodeformat,
+ b->name) < 0)
+ return -1;
+ }
+
+ bitmap->sourcebitmap = g_strdup_printf("libvirt-migration-%s", bitmap->alias);
+ bitmap->persistent = VIR_TRISTATE_BOOL_YES;
+
+ if (qemuMonitorTransactionBitmapAdd(actions,
+ disk->disk->src->nodeformat,
+ bitmap->sourcebitmap,
+ false, false, granularity) < 0)
+ return -1;
+
+ if (qemuMonitorTransactionBitmapMerge(actions,
+ disk->disk->src->nodeformat,
+ bitmap->sourcebitmap,
+ &merge) < 0)
+ return -1;
+
+ tmpbmp = g_new0(qemuDomainJobPrivateMigrateTempBitmap, 1);
+ tmpbmp->nodename = g_strdup(disk->disk->src->nodeformat);
+ tmpbmp->bitmapname = g_strdup(bitmap->sourcebitmap);
+ tmpbitmaps = g_slist_prepend(tmpbitmaps, tmpbmp);
+ }
+ }
+
+ if (qemuDomainObjEnterMonitorAsync(driver, vm, QEMU_ASYNC_JOB_MIGRATION_OUT) < 0)
+ return -1;
+
+ rc = qemuMonitorTransaction(priv->mon, &actions);
+
+ if (qemuDomainObjExitMonitor(driver, vm) < 0 || rc < 0)
+ return -1;
+
+ jobPriv->migTempBitmaps = g_steal_pointer(&tmpbitmaps);
+
+ return 0;
+}
+
+
+/**
+ * qemuMigrationSrcRunPrepareBlockDirtyBitmaps:
+ * @vm: domain object
+ * @mig: migration cookie
+ * @migParams: migration parameters
+ * @flags: migration flags
+ *
+ * Configures the source for bitmap migration when the destination asks
+ * for bitmaps.
+ */
+static int
+qemuMigrationSrcRunPrepareBlockDirtyBitmaps(virDomainObjPtr vm,
+ qemuMigrationCookiePtr mig,
+ qemuMigrationParamsPtr migParams,
+ unsigned int flags)
+
+{
+ g_autoptr(virJSONValue) mapping = NULL;
+
+ if (!mig->blockDirtyBitmaps)
+ return 0;
+
+ if (qemuMigrationCookieBlockDirtyBitmapsMatchDisks(vm->def, mig->blockDirtyBitmaps) < 0)
+ return -1;
+
+ /* For QEMU_MONITOR_MIGRATE_NON_SHARED_INC we can migrate the bitmaps
+ * directly, otherwise we must create merged bitmaps from the whole
+ * chain */
+
+ if (!(flags & QEMU_MONITOR_MIGRATE_NON_SHARED_INC) &&
+ qemuMigrationSrcRunPrepareBlockDirtyBitmapsMerge(vm, mig) < 0)
+ return -1;
+
+ if (qemuMigrationCookieBlockDirtyBitmapsToParams(mig->blockDirtyBitmaps,
+ &mapping) < 0)
+ return -1;
+
+ qemuMigrationParamsSetBlockDirtyBitmapMapping(migParams, &mapping);
+ return 0;
+}
+
+
static int
qemuMigrationSrcRun(virQEMUDriverPtr driver,
virDomainObjPtr vm,
@@ -3710,6 +4030,10 @@ qemuMigrationSrcRun(virQEMUDriverPtr driver,
cookieFlags |= QEMU_MIGRATION_COOKIE_NBD;
}
+ if (cookieFlags & QEMU_MIGRATION_COOKIE_NBD &&
+ virQEMUCapsGet(priv->qemuCaps, QEMU_CAPS_MIGRATION_PARAM_BLOCK_BITMAP_MAPPING))
+ cookieFlags |= QEMU_MIGRATION_COOKIE_BLOCK_DIRTY_BITMAPS;
+
if (virLockManagerPluginUsesState(driver->lockManager) &&
!cookieout) {
virReportError(VIR_ERR_INTERNAL_ERROR,
@@ -3742,13 +4066,18 @@ qemuMigrationSrcRun(virQEMUDriverPtr driver,
cookiein, cookieinlen,
cookieFlags |
QEMU_MIGRATION_COOKIE_GRAPHICS |
- QEMU_MIGRATION_COOKIE_CAPS);
+ QEMU_MIGRATION_COOKIE_CAPS |
+ QEMU_MIGRATION_COOKIE_BLOCK_DIRTY_BITMAPS);
if (!mig)
goto error;
if (qemuMigrationSrcGraphicsRelocate(driver, vm, mig, graphicsuri) < 0)
VIR_WARN("unable to provide data for graphics client relocation");
+ if (mig->blockDirtyBitmaps &&
+ qemuMigrationSrcRunPrepareBlockDirtyBitmaps(vm, mig, migParams, flags) < 0)
+ goto error;
+
if (qemuMigrationParamsCheck(driver, vm, QEMU_ASYNC_JOB_MIGRATION_OUT,
migParams, mig->caps->automatic) < 0)
goto error;
--
2.29.2
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