[libvirt] [PATCH 5/5] snapshot: Support reparenting external disk snapshots when deleting
Signed-off-by: Povilas Kanapickas <povilas(a)radix.lt>
---
src/qemu/qemu_driver.c | 89 ++++++++++++++++++++++++++++++++++++++++++
1 file changed, 89 insertions(+)
diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
index 227ec1c6d9..a3ffc19122 100644
--- a/src/qemu/qemu_driver.c
+++ b/src/qemu/qemu_driver.c
@@ -16590,6 +16590,7 @@ qemuDomainRevertToSnapshot(virDomainSnapshotPtr snapshot,
typedef struct _virQEMUSnapReparent virQEMUSnapReparent;
typedef virQEMUSnapReparent *virQEMUSnapReparentPtr;
struct _virQEMUSnapReparent {
+ virQEMUDriverPtr driver;
virQEMUDriverConfigPtr cfg;
virDomainSnapshotObjPtr parent;
virDomainObjPtr vm;
@@ -16617,6 +16618,88 @@
qemuDomainSnapshotReparentChildrenMetadata(virDomainSnapshotObjPtr snap,
rep->cfg->snapshotDir);
}
+static int
+qemuDomainSnapshotReparentDiskExternal(virQEMUDriverPtr driver,
+ virDomainSnapshotObjPtr parent_snap,
+ virDomainSnapshotDiskDefPtr disk)
+{
+ const char* qemu_img_path = NULL;
+ virCommandPtr cmd = NULL;
+ int i;
+ int ret = -1;
+ const char* parent_disk_path = NULL;
+
+ // Find the path to the disk we should use as the base when reparenting
+ // FIXME: what if there's no parent snapshot? i.e. we need to reparent on
+ // "empty" disk?
+ for (i = 0; i < parent_snap->def->dom->ndisks; ++i) {
+ if (STREQ(parent_snap->def->dom->disks[i]->dst, disk->name)) {
+ parent_disk_path =
parent_snap->def->dom->disks[i]->src->path;
+ break;
+ }
+ }
+
+ if (parent_disk_path == NULL) {
+ virReportError(VIR_ERR_INTERNAL_ERROR,
+ _("Could not find disk to reparent '%s' to"),
+ disk->src->path);
+ goto cleanup;
+ }
+
+ if (!(qemu_img_path = qemuFindQemuImgBinary(driver))) {
+ goto cleanup;
+ }
+
+ if (!(cmd = virCommandNewArgList(qemu_img_path,
+ "rebase", "-b",
parent_disk_path,
+ disk->src->path,
+ NULL))) {
+ goto cleanup;
+ }
+
+ if (virCommandRun(cmd, NULL) < 0)
+ goto cleanup;
+
+ ret = 0;
+cleanup:
+ virCommandFree(cmd);
+ return ret;
+}
+
+static int
+qemuDomainSnapshotReparentDisks(virDomainSnapshotObjPtr snap,
+ virQEMUSnapReparentPtr rep)
+{
+ int i;
+ virDomainSnapshotDiskDefPtr snap_disk;
+
+ if (!snap->def->dom) {
+ VIR_WARN("Any external disk snapshots in a snapshot created with "
+ "pre-0.9.5 libvirt will not be correctly reparented.");
+ // In snapshots created with pre-0.9.5 libvirt we don't have information
+ // needed to correctly reparent external disk snapshots but we also
+ // don't even know whether external disk snapshots were used so that
+ // we could report this as an error. We can only emit a warning in that
+ // case.
+ return 0;
+ }
+
+ for (i = 0; i < snap->def->ndisks; ++i) {
+ snap_disk = &(snap->def->disks[i]);
+
+ // FIXME: do we need to explicitly reparent internal snapshots to
+ // e.g. prevent long non-visible snapshot chains that might affect
+ // performance?
+ if (snap_disk->snapshot != VIR_DOMAIN_SNAPSHOT_LOCATION_EXTERNAL)
+ continue;
+
+ if (qemuDomainSnapshotReparentDiskExternal(rep->driver, rep->parent,
+ snap_disk) < 0)
+ return -1;
+ }
+ return 0;
+}
+
static int
qemuDomainSnapshotReparentChildren(void *payload,
const void *name ATTRIBUTE_UNUSED,
@@ -16628,6 +16711,11 @@ qemuDomainSnapshotReparentChildren(void *payload,
if (rep->err < 0)
return 0;
+ if (qemuDomainSnapshotReparentDisks(snap, rep) < 0) {
+ rep->err = -1;
+ goto cleanup;
+ }
+
if (qemuDomainSnapshotReparentChildrenMetadata(snap, rep) < 0) {
rep->err = -1;
goto cleanup;
@@ -16718,6 +16806,7 @@ qemuDomainSnapshotDelete(virDomainSnapshotPtr snapshot,
vm->current_snapshot = snap;
}
} else if (snap->nchildren) {
+ rep.driver = driver;
rep.cfg = cfg;
rep.parent = snap->parent;
rep.vm = vm;
--
2.17.1