From a68b849c513997e5f2513ba08dbfecce7d4e096b Mon Sep 17 00:00:00 2001
From: Pavel Hrdina <phrdina@redhat.com>
Date: Wed, 22 Feb 2023 11:43:45 +0100
Subject: [PATCH] qemu_snapshot: delete: properly update parent snapshot with
 revert data

When deleting external snapshot and parent snapshot is the currently
active snapshot as user reverted to it we need to properly update the
parent snapshot metadata.

After the delete is done the new overlay files will be the currently
used files created when snapshot revert was done, replacing the original
overlay files.

Signed-off-by: Pavel Hrdina <phrdina@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
---
 src/qemu/qemu_snapshot.c | 40 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 40 insertions(+)

diff --git a/src/qemu/qemu_snapshot.c b/src/qemu/qemu_snapshot.c
index a67be1ae49..6dd420a53b 100644
--- a/src/qemu/qemu_snapshot.c
+++ b/src/qemu/qemu_snapshot.c
@@ -3229,6 +3229,41 @@ qemuSnapshotDiscardExternal(virDomainObj *vm,
 }
 
 
+static int
+qemuSnapshotDeleteUpdateParent(virDomainObj *vm,
+                               virDomainMomentObj *parent)
+{
+    size_t i;
+    virQEMUDriver *driver = QEMU_DOMAIN_PRIVATE(vm)->driver;
+    g_autoptr(virQEMUDriverConfig) cfg = virQEMUDriverGetConfig(driver);
+    virDomainSnapshotDef *parentDef = virDomainSnapshotObjGetDef(parent);
+
+    if (!parentDef)
+        return 0;
+
+    if (!parentDef->revertdisks)
+        return 0;
+
+    for (i = 0; i < parentDef->ndisks; i++) {
+        virDomainSnapshotDiskDefClear(&parentDef->disks[i]);
+    }
+    g_free(parentDef->disks);
+
+    parentDef->disks = g_steal_pointer(&parentDef->revertdisks);
+    parentDef->ndisks = parentDef->nrevertdisks;
+    parentDef->nrevertdisks = 0;
+
+    if (qemuDomainSnapshotWriteMetadata(vm,
+                                        parent,
+                                        driver->xmlopt,
+                                        cfg->snapshotDir) < 0) {
+        return -1;
+    }
+
+    return 0;
+}
+
+
 static int
 qemuSnapshotDiscardMetadata(virDomainObj *vm,
                             virDomainMomentObj *snap,
@@ -3268,6 +3303,11 @@ qemuSnapshotDiscardMetadata(virDomainObj *vm,
         virDomainMomentMoveChildren(snap, snap->parent);
     }
 
+    if (update_parent && snap->parent) {
+        if (qemuSnapshotDeleteUpdateParent(vm, snap->parent) < 0)
+            ret = -1;
+    }
+
     snapFile = g_strdup_printf("%s/%s/%s.xml", cfg->snapshotDir, vm->def->name,
                                snap->def->name);