On Thu, Feb 11, 2021 at 16:37:57 +0100, Peter Krempa wrote:
> 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@xxxxxxxxxx>
> ---
> 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 36424f8493..16bfad0390 100644
> --- a/src/qemu/qemu_migration.c
> +++ b/src/qemu/qemu_migration.c
...
> @@ -2528,6 +2619,92 @@ 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;
Shouldn't we report an error in case the source sent bitmaps, but local
QEMU does not support QEMU_CAPS_MIGRATION_PARAM_BLOCK_BITMAP_MAPPING?
> +
> + 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;
> + }
> +
> + /* don't migrate bitmaps into non-qcow2v3+ images */
How about "Bitmaps can only be migrated to qcow2 v3+"?
> + if (disk->disk->src->format != VIR_STORAGE_FILE_QCOW2 ||
> + nodedata->qcow2v2) {
> + disk->skip = true;
Is skipping the disk the right thing to do? Should we report an error
and abort migration instead? Just checking, maybe we can't do so for
backward compatibility...
> + 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;
And similar questions for bitmaps here.
> + 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,
...
> +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" is missing in the check.
> + return -1;
> +
> + if (qemuMigrationCookieBlockDirtyBitmapsToParams(mig->blockDirtyBitmaps,
> + &mapping) < 0)
> + return -1;
> +
> + qemuMigrationParamsSetBlockDirtyBitmapMapping(migParams, &mapping);
> + return 0;
> +}
> +
> +
> static int
> qemuMigrationSrcRun(virQEMUDriverPtr driver,
> virDomainObjPtr vm,
Jirka
