[PATCH 30/35] 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(a)redhat.com>
---
src/qemu/qemu_hotplug.c | 52 ++++++++++++++++++++++++++++++++++++-----
1 file changed, 46 insertions(+), 6 deletions(-)
diff --git a/src/qemu/qemu_hotplug.c b/src/qemu/qemu_hotplug.c
index e13a739ade..59832ea2b3 100644
--- a/src/qemu/qemu_hotplug.c
+++ b/src/qemu/qemu_hotplug.c
@@ -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;
--
2.31.1