[libvirt PATCH v2 22/31] qemu_snapshot: error out when deleting internal snapshot on non-active disk

[Pavel Hrdina]

Deleting internal snapshot when the currently active disk image is
different than where the internal snapshot was taken doesn't work
correctly.

This applies to a running VM only as we are using QMP command and
talking to the QEMU process that is using different disk.

This works correctly when the VM is shut of as in this case we spawn
qemu-img process to delete the snapshot.

Signed-off-by: Pavel Hrdina <phrdina at redhat.com>
Reviewed-by: Peter Krempa <pkrempa at redhat.com>
---
 src/qemu/qemu_snapshot.c | 26 ++++++++++++++++++++++++--
 1 file changed, 24 insertions(+), 2 deletions(-)

diff --git a/src/qemu/qemu_snapshot.c b/src/qemu/qemu_snapshot.c
index d7da317e22..31e7087081 100644
--- a/src/qemu/qemu_snapshot.c
+++ b/src/qemu/qemu_snapshot.c
@@ -2492,9 +2492,31 @@ qemuSnapshotCountExternalInternal(void *payload,
 
 
 static int
-qemuSnapshotDeleteValidate(virDomainMomentObj *snap,
+qemuSnapshotDeleteValidate(virDomainObj *vm,
+                           virDomainMomentObj *snap,
                            unsigned int flags)
 {
+    if (!virDomainSnapshotIsExternal(snap) &&
+        virDomainObjIsActive(vm)) {
+        ssize_t i;
+        virDomainSnapshotDef *snapdef = virDomainSnapshotObjGetDef(snap);
+
+        for (i = 0; i < snapdef->ndisks; i++) {
+            virDomainSnapshotDiskDef *snapDisk = &(snapdef->disks[i]);
+            virDomainDiskDef *vmdisk = NULL;
+            virDomainDiskDef *disk = NULL;
+
+            vmdisk = qemuDomainDiskByName(vm->def, snapDisk->name);
+            disk = qemuDomainDiskByName(snapdef->parent.dom, snapDisk->name);
+
+            if (!virStorageSourceIsSameLocation(vmdisk->src, disk->src)) {
+                virReportError(VIR_ERR_OPERATION_UNSUPPORTED,
+                               _("disk image '%s' for internal snapshot '%s' is not the same as disk image currently used by VM"),
+                               snapDisk->name, snap->def->name);
+                return -1;
+            }
+        }
+    }
 
     if (flags & (VIR_DOMAIN_SNAPSHOT_DELETE_CHILDREN |
                  VIR_DOMAIN_SNAPSHOT_DELETE_CHILDREN_ONLY)) {
@@ -2548,7 +2570,7 @@ qemuSnapshotDelete(virDomainObj *vm,
         goto endjob;
 
     if (!metadata_only) {
-        if (qemuSnapshotDeleteValidate(snap, flags) < 0)
+        if (qemuSnapshotDeleteValidate(vm, snap, flags) < 0)
             goto endjob;
     }
 
-- 
2.39.0