[libvirt] [PATCH v2 08/11] lxc: Grab modify job for changing domain XML

[Michal Privoznik]

The reasoning here is the same as in qemu driver fixed in
previous commit. Long story short, changing an XML of a domain
requires modify job to be acquired.

Signed-off-by: Michal Privoznik <mprivozn at redhat.com>
---
 src/lxc/lxc_domain.c | 57 ++++++++++++++++++++++++++++++++++++++++++++
 src/lxc/lxc_domain.h |  7 ++++++
 src/lxc/lxc_driver.c | 11 +++------
 3 files changed, 67 insertions(+), 8 deletions(-)

diff --git a/src/lxc/lxc_domain.c b/src/lxc/lxc_domain.c
index 51a9fd36eb..800999cbed 100644
--- a/src/lxc/lxc_domain.c
+++ b/src/lxc/lxc_domain.c
@@ -47,6 +47,63 @@ VIR_ENUM_IMPL(virLXCDomainJob,
 
 VIR_LOG_INIT("lxc.lxc_domain");
 
+
+/**
+ * lxcDomainObjListAdd:
+ * @driver: LXC driver
+ * @def: domain definition
+ * @oldDef: previous domain definition
+ * @live: whether @def is live definition
+ * @flags: an bitwise-OR of virDomainObjListAdd flags
+ *
+ * Add a domain onto the list of domain object and sets its
+ * definition. If @oldDef is not NULL and there was pre-existing
+ * definition it's returned in @oldDef.
+ *
+ * In addition to that, if definition of an existing domain is
+ * changed a MODIFY job is acquired prior to that.
+ *
+ * Returns: domain object pointer on success,
+ *          NULL otherwise.
+ */
+virDomainObjPtr
+lxcDomainObjListAdd(virLXCDriverPtr driver,
+                    virDomainDefPtr def,
+                    virDomainDefPtr *oldDef,
+                    bool live,
+                    unsigned int flags)
+{
+    virDomainObjPtr vm = NULL;
+
+    if (!(vm = virDomainObjListAdd(driver->domains, def, driver->xmlopt, flags)))
+        return NULL;
+
+    /* At this point, @vm is locked. If it doesn't have any
+     * definition set, then the call above just added it and
+     * there can't be anybody else using the object. It's safe to
+     * just set the definition without acquiring job. */
+    if (!vm->def) {
+        virDomainObjAssignDef(vm, def, live, oldDef);
+        VIR_RETURN_PTR(vm);
+    }
+
+    /* Bad luck. Domain was pre-existing and this call is trying
+     * to update its definition. Modify job MUST be acquired. */
+    if (virLXCDomainObjBeginJob(driver, vm, LXC_JOB_MODIFY) < 0) {
+        if (!vm->persistent)
+            virDomainObjListRemove(driver->domains, vm);
+        virDomainObjEndAPI(&vm);
+        return NULL;
+    }
+
+    virDomainObjAssignDef(vm, def, live, oldDef);
+
+    virLXCDomainObjEndJob(driver, vm);
+
+    return vm;
+}
+
+
 static int
 virLXCDomainObjInitJob(virLXCDomainObjPrivatePtr priv)
 {
diff --git a/src/lxc/lxc_domain.h b/src/lxc/lxc_domain.h
index 2048481829..522cf7917d 100644
--- a/src/lxc/lxc_domain.h
+++ b/src/lxc/lxc_domain.h
@@ -96,6 +96,13 @@ extern virDomainXMLNamespace virLXCDriverDomainXMLNamespace;
 extern virDomainXMLPrivateDataCallbacks virLXCDriverPrivateDataCallbacks;
 extern virDomainDefParserConfig virLXCDriverDomainDefParserConfig;
 
+virDomainObjPtr
+lxcDomainObjListAdd(virLXCDriverPtr driver,
+                    virDomainDefPtr def,
+                    virDomainDefPtr *oldDef,
+                    bool live,
+                    unsigned int flags);
+
 int
 virLXCDomainObjBeginJob(virLXCDriverPtr driver,
                        virDomainObjPtr obj,
diff --git a/src/lxc/lxc_driver.c b/src/lxc/lxc_driver.c
index eaf26563f5..41e6b59927 100644
--- a/src/lxc/lxc_driver.c
+++ b/src/lxc/lxc_driver.c
@@ -444,12 +444,10 @@ lxcDomainDefineXMLFlags(virConnectPtr conn, const char *xml, unsigned int flags)
         goto cleanup;
     }
 
-    if (!(vm = virDomainObjListAdd(driver->domains, def,
-                                   driver->xmlopt, 0)))
+    if (!(vm = lxcDomainObjListAdd(driver, def, &oldDef, false, 0)))
         goto cleanup;
-
-    virDomainObjAssignDef(vm, def, false, &oldDef);
     def = NULL;
+
     vm->persistent = 1;
 
     if (virDomainSaveConfig(cfg->configDir, driver->caps,
@@ -1191,12 +1189,9 @@ lxcDomainCreateXMLWithFiles(virConnectPtr conn,
     }
 
 
-    if (!(vm = virDomainObjListAdd(driver->domains, def,
-                                   driver->xmlopt,
+    if (!(vm = lxcDomainObjListAdd(driver, def, NULL, true,
                                    VIR_DOMAIN_OBJ_LIST_ADD_CHECK_LIVE)))
         goto cleanup;
-
-    virDomainObjAssignDef(vm, def, true, NULL);
     def = NULL;
 
     if (virLXCDomainObjBeginJob(driver, vm, LXC_JOB_MODIFY) < 0) {
-- 
2.21.0