qemuDomainAttachDiskGeneric: Implement hotplug of <transient> disk

Add code which creates the transient overlay after hotplugging the disk
backend before attaching the disk frontend.

The state of the topmost image is modified to be already read-only to
prevent the need to open the image in read-write mode.

Signed-off-by: Peter Krempa <pkrempa@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
Reviewed-by: Pavel Hrdina <phrdina@redhat.com>
This commit is contained in:
Peter Krempa 2021-05-13 13:05:27 +02:00
parent 34c3291139
commit 2e94002d2a

View File

@ -34,6 +34,7 @@
#include "qemu_process.h"
#include "qemu_security.h"
#include "qemu_block.h"
#include "qemu_snapshot.h"
#include "domain_audit.h"
#include "netdev_bandwidth_conf.h"
#include "domain_nwfilter.h"
@ -685,6 +686,25 @@ qemuDomainChangeEjectableMedia(virQEMUDriver *driver,
}
static qemuSnapshotDiskContext *
qemuDomainAttachDiskGenericTransient(virDomainObj *vm,
virDomainDiskDef *disk,
GHashTable *blockNamedNodeData)
{
g_autoptr(qemuSnapshotDiskContext) snapctxt = NULL;
g_autoptr(virDomainSnapshotDiskDef) snapdiskdef = NULL;
snapdiskdef = qemuSnapshotGetTransientDiskDef(disk, vm->def->name);
snapctxt = qemuSnapshotDiskContextNew(1, vm, QEMU_ASYNC_JOB_NONE);
if (qemuSnapshotDiskPrepareOne(snapctxt, disk, snapdiskdef,
blockNamedNodeData, false, false) < 0)
return NULL;
return g_steal_pointer(&snapctxt);
}
/**
* qemuDomainAttachDiskGeneric:
*
@ -701,6 +721,11 @@ qemuDomainAttachDiskGeneric(virQEMUDriver *driver,
bool blockdev = virQEMUCapsGet(priv->qemuCaps, QEMU_CAPS_BLOCKDEV);
bool extensionDeviceAttached = false;
int rc;
g_autoptr(qemuSnapshotDiskContext) transientDiskSnapshotCtxt = NULL;
bool origReadonly = disk->src->readonly;
if (disk->transient)
disk->src->readonly = true;
if (virStorageSourceGetActualType(disk->src) == VIR_STORAGE_TYPE_VHOST_USER) {
if (!(data = qemuBuildStorageSourceChainAttachPrepareChardev(disk)))
@ -723,6 +748,8 @@ qemuDomainAttachDiskGeneric(virQEMUDriver *driver,
return -1;
}
disk->src->readonly = origReadonly;
qemuDomainObjEnterMonitor(driver, vm);
rc = qemuBlockStorageSourceChainAttach(priv->mon, data);
@ -733,6 +760,25 @@ qemuDomainAttachDiskGeneric(virQEMUDriver *driver,
if (rc < 0)
goto rollback;
if (disk->transient) {
g_autoptr(qemuBlockStorageSourceAttachData) backend = NULL;
g_autoptr(GHashTable) blockNamedNodeData = NULL;
if (!(blockNamedNodeData = qemuBlockGetNamedNodeData(vm, QEMU_ASYNC_JOB_NONE)))
goto rollback;
if (!(transientDiskSnapshotCtxt = qemuDomainAttachDiskGenericTransient(vm, disk, blockNamedNodeData)))
goto rollback;
if (qemuSnapshotDiskCreate(transientDiskSnapshotCtxt) < 0)
goto rollback;
QEMU_DOMAIN_DISK_PRIVATE(disk)->transientOverlayCreated = true;
backend = qemuBlockStorageSourceDetachPrepare(disk->src, NULL);
ignore_value(VIR_INSERT_ELEMENT(data->srcdata, 0, data->nsrcdata, backend));
}
if (!(devstr = qemuBuildDiskDeviceStr(vm->def, disk, priv->qemuCaps)))
goto rollback;
@ -937,12 +983,6 @@ qemuDomainAttachDeviceDiskLiveInternal(virQEMUDriver *driver,
return -1;
}
if (disk->transient) {
virReportError(VIR_ERR_OPERATION_UNSUPPORTED, "%s",
_("transient disk hotplug isn't supported"));
return -1;
}
if (virDomainDiskTranslateSourcePool(disk) < 0)
goto cleanup;