From e03a62b456a04db159d43cd6dc5c1a3520b9b1ad Mon Sep 17 00:00:00 2001
From: Eric Blake <eblake@redhat.com>
Date: Fri, 19 Aug 2011 22:03:38 -0600
Subject: [PATCH] snapshot: add flag for requesting disk snapshot

Prior to this patch, <domainsnapshot>/<disks> was ignored.  This
changes it to be an error unless an explicit disk snapshot is
requested (a future patch may relax things if it turns out to
be useful to have a <disks> specification alongside a system
checkpoint).

* include/libvirt/libvirt.h.in
(VIR_DOMAIN_SNAPSHOT_CREATE_DISK_ONLY): New flag.
* src/libvirt.c (virDomainSnapshotCreateXML): Document it.
* src/esx/esx_driver.c (esxDomainSnapshotCreateXML): Disk
snapshots not supported yet.
* src/vbox/vbox_tmpl.c (vboxDomainSnapshotCreateXML): Likewise.
* src/qemu/qemu_driver.c (qemuDomainSnapshotCreateXML): Likewise.
---
 include/libvirt/libvirt.h.in | 2 ++
 src/esx/esx_driver.c         | 6 ++++++
 src/libvirt.c                | 6 ++++++
 src/qemu/qemu_driver.c       | 6 ++++++
 src/vbox/vbox_tmpl.c         | 6 ++++++
 5 files changed, 26 insertions(+)

diff --git a/include/libvirt/libvirt.h.in b/include/libvirt/libvirt.h.in
index 4292736f8a..157bef2045 100644
--- a/include/libvirt/libvirt.h.in
+++ b/include/libvirt/libvirt.h.in
@@ -2581,6 +2581,8 @@ typedef enum {
                                                           remembering it */
     VIR_DOMAIN_SNAPSHOT_CREATE_HALT        = (1 << 3), /* Stop running guest
                                                           after snapshot */
+    VIR_DOMAIN_SNAPSHOT_CREATE_DISK_ONLY   = (1 << 4), /* disk snapshot, not
+                                                          system checkpoint */
 } virDomainSnapshotCreateFlags;
 
 /* Take a snapshot of the current VM state */
diff --git a/src/esx/esx_driver.c b/src/esx/esx_driver.c
index 18edc454fd..f1102eac32 100644
--- a/src/esx/esx_driver.c
+++ b/src/esx/esx_driver.c
@@ -4226,6 +4226,12 @@ esxDomainSnapshotCreateXML(virDomainPtr domain, const char *xmlDesc,
         return NULL;
     }
 
+    if (def->ndisks) {
+        ESX_ERROR(VIR_ERR_CONFIG_UNSUPPORTED, "%s",
+                  _("disk snapshots not supported yet"));
+        return NULL;
+    }
+
     if (esxVI_LookupVirtualMachineByUuidAndPrepareForTask
           (priv->primary, domain->uuid, NULL, &virtualMachine,
            priv->parsedUri->autoAnswer) < 0 ||
diff --git a/src/libvirt.c b/src/libvirt.c
index b29779ef7d..89d1539e7e 100644
--- a/src/libvirt.c
+++ b/src/libvirt.c
@@ -15643,6 +15643,12 @@ error:
  * running after the snapshot.  This flag is invalid on transient domains,
  * and is incompatible with VIR_DOMAIN_SNAPSHOT_CREATE_REDEFINE.
  *
+ * If @flags includes VIR_DOMAIN_SNAPSHOT_CREATE_DISK_ONLY, then the
+ * snapshot will be limited to the disks described in @xmlDesc, and no
+ * VM state will be saved.  For an active guest, the disk image may be
+ * inconsistent (as if power had been pulled), and specifying this
+ * with the VIR_DOMAIN_SNAPSHOT_CREATE_HALT flag risks data loss.
+ *
  * Returns an (opaque) virDomainSnapshotPtr on success, NULL on failure.
  */
 virDomainSnapshotPtr
diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
index d1c8659fcb..3a68862f5d 100644
--- a/src/qemu/qemu_driver.c
+++ b/src/qemu/qemu_driver.c
@@ -8899,6 +8899,12 @@ qemuDomainSnapshotCreateXML(virDomainPtr domain,
     if (!qemuDomainSnapshotIsAllowed(vm))
         goto cleanup;
 
+    if (def->ndisks) {
+        qemuReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s",
+                        _("disk snapshots not supported yet"));
+        goto cleanup;
+    }
+
     if (!(snap = virDomainSnapshotAssignDef(&vm->snapshots, def)))
         goto cleanup;
     def = NULL;
diff --git a/src/vbox/vbox_tmpl.c b/src/vbox/vbox_tmpl.c
index cbe34e8f5e..0e4364f67e 100644
--- a/src/vbox/vbox_tmpl.c
+++ b/src/vbox/vbox_tmpl.c
@@ -5661,6 +5661,12 @@ vboxDomainSnapshotCreateXML(virDomainPtr dom,
     if (!(def = virDomainSnapshotDefParseString(xmlDesc, NULL, 0, 0)))
         goto cleanup;
 
+    if (def->ndisks) {
+        vboxError(VIR_ERR_CONFIG_UNSUPPORTED, "%s",
+                  _("disk snapshots not supported yet"));
+        goto cleanup;
+    }
+
     vboxIIDFromUUID(&domiid, dom->uuid);
     rc = VBOX_OBJECT_GET_MACHINE(domiid.value, &machine);
     if (NS_FAILED(rc)) {