[libvirt PATCH 2/3] Introduce VIR_DOMAIN_PAUSED_API_ERROR

[Jiri Denemark]

Some APIs (migration, save/restore, snapshot, ...) require a domain to
be suspended temporarily. In case resuming the domain fails, the domain
will be unexpectedly left paused when the API finishes. This situation
is reported via VIR_DOMAIN_EVENT_SUSPENDED event with
VIR_DOMAIN_EVENT_SUSPENDED_API_ERROR detail. But we do not have a
corresponding reason for VIR_DOMAIN_PAUSED state and the reason would
remain set to the value used when the domain was paused. So the state
reason would suggest the operation is still running.

This patch changes the state reason to a new VIR_DOMAIN_PAUSED_API_ERROR
to make it clear the API that paused the domain already finished, but
failed to resume the domain.

Signed-off-by: Jiri Denemark <jdenemar at redhat.com>
---
 include/libvirt/libvirt-domain.h | 1 +
 src/conf/domain_conf.c           | 1 +
 src/qemu/qemu_domain.c           | 3 +++
 src/qemu/qemu_driver.c           | 8 ++++++++
 src/qemu/qemu_snapshot.c         | 8 ++++++++
 tools/virsh-domain-monitor.c     | 1 +
 6 files changed, 22 insertions(+)

diff --git a/include/libvirt/libvirt-domain.h b/include/libvirt/libvirt-domain.h
index 53cab6bd4c..3ebb2c6642 100644
--- a/include/libvirt/libvirt-domain.h
+++ b/include/libvirt/libvirt-domain.h
@@ -148,6 +148,7 @@ typedef enum {
     VIR_DOMAIN_PAUSED_STARTING_UP = 11, /* the domain is being started (Since: 1.2.14) */
     VIR_DOMAIN_PAUSED_POSTCOPY = 12,    /* paused for post-copy migration (Since: 1.3.3) */
     VIR_DOMAIN_PAUSED_POSTCOPY_FAILED = 13, /* paused after failed post-copy (Since: 1.3.3) */
+    VIR_DOMAIN_PAUSED_API_ERROR = 14,   /* Some APIs (e.g., migration, snapshot) internally need to suspend a domain. This paused state reason is used when resume operation at the end of such API fails. (Since: 9.2.0) */
 
 # ifdef VIR_ENUM_SENTINELS
     VIR_DOMAIN_PAUSED_LAST /* (Since: 0.9.10) */
diff --git a/src/conf/domain_conf.c b/src/conf/domain_conf.c
index 34d38f9958..f9b28acc76 100644
--- a/src/conf/domain_conf.c
+++ b/src/conf/domain_conf.c
@@ -1163,6 +1163,7 @@ VIR_ENUM_IMPL(virDomainPausedReason,
               "starting up",
               "post-copy",
               "post-copy failed",
+              "api error",
 );
 
 VIR_ENUM_IMPL(virDomainShutdownReason,
diff --git a/src/qemu/qemu_domain.c b/src/qemu/qemu_domain.c
index f5fd140c85..fb269d0cd1 100644
--- a/src/qemu/qemu_domain.c
+++ b/src/qemu/qemu_domain.c
@@ -11372,6 +11372,9 @@ qemuDomainPausedReasonToSuspendedEvent(virDomainPausedReason reason)
     case VIR_DOMAIN_PAUSED_POSTCOPY:
         return VIR_DOMAIN_EVENT_SUSPENDED_POSTCOPY;
 
+    case VIR_DOMAIN_PAUSED_API_ERROR:
+        return VIR_DOMAIN_EVENT_SUSPENDED_API_ERROR;
+
     case VIR_DOMAIN_PAUSED_UNKNOWN:
     case VIR_DOMAIN_PAUSED_USER:
     case VIR_DOMAIN_PAUSED_SAVE:
diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
index 3f353eadfa..7256c75c47 100644
--- a/src/qemu/qemu_driver.c
+++ b/src/qemu/qemu_driver.c
@@ -2727,6 +2727,10 @@ qemuDomainSaveInternal(virQEMUDriver *driver,
                                      virDomainEventLifecycleNewFromObj(vm,
                                          VIR_DOMAIN_EVENT_SUSPENDED,
                                          VIR_DOMAIN_EVENT_SUSPENDED_API_ERROR));
+                if (virDomainObjGetState(vm, NULL) == VIR_DOMAIN_PAUSED) {
+                    virDomainObjSetState(vm, VIR_DOMAIN_PAUSED,
+                                         VIR_DOMAIN_PAUSED_API_ERROR);
+                }
             }
             virErrorRestore(&save_err);
         }
@@ -3254,6 +3258,10 @@ qemuDomainCoreDumpWithFormat(virDomainPtr dom,
                 event = virDomainEventLifecycleNewFromObj(vm,
                                                           VIR_DOMAIN_EVENT_SUSPENDED,
                                                           VIR_DOMAIN_EVENT_SUSPENDED_API_ERROR);
+                if (virDomainObjGetState(vm, NULL) == VIR_DOMAIN_PAUSED) {
+                    virDomainObjSetState(vm, VIR_DOMAIN_PAUSED,
+                                         VIR_DOMAIN_PAUSED_API_ERROR);
+                }
                 if (virGetLastErrorCode() == VIR_ERR_OK)
                     virReportError(VIR_ERR_OPERATION_FAILED,
                                    "%s", _("resuming after dump failed"));
diff --git a/src/qemu/qemu_snapshot.c b/src/qemu/qemu_snapshot.c
index cfa531edef..e101b43dd3 100644
--- a/src/qemu/qemu_snapshot.c
+++ b/src/qemu/qemu_snapshot.c
@@ -326,6 +326,10 @@ qemuSnapshotCreateActiveInternal(virQEMUDriver *driver,
         event = virDomainEventLifecycleNewFromObj(vm,
                                          VIR_DOMAIN_EVENT_SUSPENDED,
                                          VIR_DOMAIN_EVENT_SUSPENDED_API_ERROR);
+        if (virDomainObjGetState(vm, NULL) == VIR_DOMAIN_PAUSED) {
+            virDomainObjSetState(vm, VIR_DOMAIN_PAUSED,
+                                 VIR_DOMAIN_PAUSED_API_ERROR);
+        }
         if (virGetLastErrorCode() == VIR_ERR_OK) {
             virReportError(VIR_ERR_OPERATION_FAILED, "%s",
                            _("resuming after snapshot failed"));
@@ -1398,6 +1402,10 @@ qemuSnapshotCreateActiveExternal(virQEMUDriver *driver,
                                          VIR_DOMAIN_EVENT_SUSPENDED,
                                          VIR_DOMAIN_EVENT_SUSPENDED_API_ERROR);
         virObjectEventStateQueue(driver->domainEventState, event);
+        if (virDomainObjGetState(vm, NULL) == VIR_DOMAIN_PAUSED) {
+            virDomainObjSetState(vm, VIR_DOMAIN_PAUSED,
+                                 VIR_DOMAIN_PAUSED_API_ERROR);
+        }
         if (virGetLastErrorCode() == VIR_ERR_OK) {
             virReportError(VIR_ERR_OPERATION_FAILED, "%s",
                            _("resuming after snapshot failed"));
diff --git a/tools/virsh-domain-monitor.c b/tools/virsh-domain-monitor.c
index c2134faba1..bdade8f251 100644
--- a/tools/virsh-domain-monitor.c
+++ b/tools/virsh-domain-monitor.c
@@ -192,6 +192,7 @@ VIR_ENUM_IMPL(virshDomainPausedReason,
               N_("starting up"),
               N_("post-copy"),
               N_("post-copy failed"),
+              N_("api error"),
 );
 
 VIR_ENUM_DECL(virshDomainShutdownReason);
-- 
2.39.2