[libvirt PATCH] qemu_snapshot: fix snapshot deletion that had multiple children
When we revert to non-leaf snapshot and create new branch or branches
the overlay in snapshot metadata is no longer usable as a disk source
for deletion of that snapshot. We need to use other places to figure out
the correct storage source.
Fixes: https://gitlab.com/libvirt/libvirt/-/issues/534
Signed-off-by: Pavel Hrdina <phrdina(a)redhat.com>
---
src/qemu/qemu_snapshot.c | 46 ++++++++++++++++++++++++++++++++++++++--
1 file changed, 44 insertions(+), 2 deletions(-)
diff --git a/src/qemu/qemu_snapshot.c b/src/qemu/qemu_snapshot.c
index 1962ba4027..ee06e72b11 100644
--- a/src/qemu/qemu_snapshot.c
+++ b/src/qemu/qemu_snapshot.c
@@ -2748,6 +2748,44 @@ qemuSnapshotGetDisksWithBackingStore(virDomainObj *vm,
}
+/**
+ * qemuSnapshotExternalGetSnapDiskSrc:
+ * @vm: domain object
+ * @snap: snapshot object
+ * @snapDisk: disk definition from snapshost
+ *
+ * Try to get actual disk source for @snapDisk as the source stored in
+ * snapshot metadata is not always the correct source we need to work with.
+ * This happens mainly after reverting to non-leaf snapshot and creating
+ * new branch with new snapshot.
+ *
+ * Returns disk source on success, NULL on error.
+ */
+static virStorageSource *
+qemuSnapshotExternalGetSnapDiskSrc(virDomainObj *vm,
+ virDomainMomentObj *snap,
+ virDomainSnapshotDiskDef *snapDisk)
+{
+ virDomainDiskDef *disk = NULL;
+
+ /* Should never happen when deleting external snapshot as for now we do
+ * not support this specific case for now. */
+ if (snap->nchildren > 1)
+ return snapDisk->src;
+
+ if (snap->first_child) {
+ disk = qemuDomainDiskByName(snap->first_child->def->dom,
snapDisk->name);
+ } else if (virDomainSnapshotGetCurrent(vm->snapshots) == snap) {
+ disk = qemuDomainDiskByName(vm->def, snapDisk->name);
+ }
+
+ if (disk)
+ return disk->src;
+
+ return snapDisk->src;
+}
+
+
/**
* qemuSnapshotDeleteExternalPrepareData:
* @vm: domain object
@@ -2802,18 +2840,22 @@ qemuSnapshotDeleteExternalPrepareData(virDomainObj *vm,
}
if (data->merge) {
+ virStorageSource *snapDiskSrc = NULL;
+
data->domDisk = qemuDomainDiskByName(vm->def, snapDisk->name);
if (!data->domDisk)
return -1;
+ snapDiskSrc = qemuSnapshotExternalGetSnapDiskSrc(vm, snap,
data->snapDisk);
+
if (virDomainObjIsActive(vm)) {
data->diskSrc =
virStorageSourceChainLookupBySource(data->domDisk->src,
-
data->snapDisk->src,
+ snapDiskSrc,
&data->prevDiskSrc);
if (!data->diskSrc)
return -1;
- if (!virStorageSourceIsSameLocation(data->diskSrc,
data->snapDisk->src)) {
+ if (!virStorageSourceIsSameLocation(data->diskSrc, snapDiskSrc)) {
virReportError(VIR_ERR_OPERATION_FAILED, "%s",
_("VM disk source and snapshot disk source are
not the same"));
return -1;
--
2.41.0