From 88d0e6748df5afe8d598cd39f49c0bd05e5e18c0 Mon Sep 17 00:00:00 2001 From: Pavel Hrdina Date: Mon, 6 Mar 2023 12:25:04 +0100 Subject: [PATCH] qemu_snapshot: add checks for external snapshot deletion With the introduction of external snapshot revert support we need to error out in some cases when trying to delete some snapshots. If users reverts to non-leaf snapshots and would try to delete it after the revert is done it would not work currently as this operation would require using block-stream which is not implemented for now as in this case the snapshot has two children so the disk files have multiple overlays. Similarly if user reverts to non-leaf snapshot and would try to delete snapshot that is non-leaf but not in currently active snapshot chain we would still need to use block-commit operation. The issue here is that in order to do that we would have to start new qemu process with different domain definition than what is currently used by the domain. If the current domain would be running it would complicate things even more so this operation is not yet supported. If user creates new snapshot after reverting to non-leaf snapshot it creates a new branch. Deleting snapshot with multiple children will require block-stream which is not implemented for now. Signed-off-by: Pavel Hrdina Reviewed-by: Peter Krempa --- src/qemu/qemu_snapshot.c | 21 +++++++++++++++++++++ 1 file changed, 21 insertions(+) diff --git a/src/qemu/qemu_snapshot.c b/src/qemu/qemu_snapshot.c index dca95b415b..692d88e24d 100644 --- a/src/qemu/qemu_snapshot.c +++ b/src/qemu/qemu_snapshot.c @@ -3729,6 +3729,8 @@ qemuSnapshotDeleteValidate(virDomainObj *vm, } if (virDomainSnapshotIsExternal(snap)) { + virDomainMomentObj *current = virDomainSnapshotGetCurrent(vm->snapshots); + if (qemuDomainHasBlockjob(vm, false)) { virReportError(VIR_ERR_OPERATION_UNSUPPORTED, "%s", _("cannot delete external snapshots when there is another active block job")); @@ -3740,6 +3742,25 @@ qemuSnapshotDeleteValidate(virDomainObj *vm, _("deletion of external disk snapshots with children not supported")); return -1; } + + if (snap == current && snap->nchildren != 0) { + virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s", + _("deletion of active external snapshot that is not a leaf snapshot is not supported")); + return -1; + } + + if (snap != current && snap->nchildren != 0 && + virDomainMomentIsAncestor(snap, current)) { + virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s", + _("deletion of non-leaf external snapshot that is not in active chain is not supported")); + return -1; + } + + if (snap->nchildren > 1) { + virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s", + _("deletion of external disk snapshot with multiple children snapshots not supported")); + return -1; + } } return 0;