[Libvirt-cim] [PATCH 2/4] CSI, add lock to protect shared data

[Wenchao Xia]

  This patch added lock on shared data without which may trigger
incorrect data operation. Global lock is used so speed may be slowed
down, it can be improved in the future.

Signed-off-by: Wenchao Xia <xiawenc at linux.vnet.ibm.com>
---
 src/Virt_ComputerSystemIndication.c |   39 ++++++++++++++++++++++++++++++++--
 1 files changed, 36 insertions(+), 3 deletions(-)

diff --git a/src/Virt_ComputerSystemIndication.c b/src/Virt_ComputerSystemIndication.c
index b1b9fa0..3159ca0 100644
--- a/src/Virt_ComputerSystemIndication.c
+++ b/src/Virt_ComputerSystemIndication.c
@@ -174,9 +174,11 @@ static void csi_free_thread_data(void *data)
         if (data == NULL)
                 return;
 
+        pthread_mutex_lock(&lifecycle_mutex);
         list_free(thread->dom_list);
         thread->dom_list = NULL;
         stdi_free_ind_args(&thread->args);
+        pthread_mutex_unlock(&lifecycle_mutex);
 }
 
 void set_source_inst_props(const CMPIBroker *broker,
@@ -490,6 +492,8 @@ static int update_domain_list(virConnectPtr conn, csi_thread_data_t *thread)
         return s.rc;
 }
 
+/* following function will protect global data with lifecycle_mutex.
+   TODO: improve it with seperate lock later. */
 static void csi_domain_event_cb(virConnectPtr conn,
                                 virDomainPtr dom,
                                 int event,
@@ -502,10 +506,13 @@ static void csi_domain_event_cb(virConnectPtr conn,
         char *prefix = class_prefix_name(thread->args->classname);
         CMPIStatus s = {CMPI_RC_OK, NULL};
 
+        pthread_mutex_lock(&lifecycle_mutex);
         if (lifecycle_enabled == false || thread->active_filters <= 0) {
                 CU_DEBUG("%s indications deactivated, return", prefix);
+                pthread_mutex_unlock(&lifecycle_mutex);
                 return;
         }
+        pthread_mutex_unlock(&lifecycle_mutex);
 
         CU_DEBUG("Event: Domain %s(%d) event: %d detail: %d\n",
                  virDomainGetName(dom), virDomainGetID(dom), event, detail);
@@ -537,7 +544,9 @@ static void csi_domain_event_cb(virConnectPtr conn,
         if (cs_event != CS_CREATED) {
                 char uuid[VIR_UUID_STRING_BUFLEN] = {0};
                 virDomainGetUUIDString(dom, &uuid[0]);
+                pthread_mutex_lock(&lifecycle_mutex);
                 dom_xml = list_find(thread->dom_list, uuid);
+                pthread_mutex_unlock(&lifecycle_mutex);
         }
 
         if (dom_xml == NULL) {
@@ -545,12 +554,16 @@ static void csi_domain_event_cb(virConnectPtr conn,
                 goto end;
         }
 
+        pthread_mutex_lock(&lifecycle_mutex);
         async_ind(thread->args, cs_event, dom_xml, prefix);
+        pthread_mutex_unlock(&lifecycle_mutex);
 
         /* Update the domain list accordingly */
         if (event == VIR_DOMAIN_EVENT_DEFINED) {
                 if (detail == VIR_DOMAIN_EVENT_DEFINED_ADDED) {
+                        pthread_mutex_lock(&lifecycle_mutex);
                         csi_thread_dom_list_append(thread, dom_xml);
+                        pthread_mutex_unlock(&lifecycle_mutex);
                 } else if (detail == VIR_DOMAIN_EVENT_DEFINED_UPDATED) {
                         free(dom_xml->name);
                         free(dom_xml->xml);
@@ -558,7 +571,9 @@ static void csi_domain_event_cb(virConnectPtr conn,
                 }
         } else if (event == VIR_DOMAIN_EVENT_DEFINED &&
                    detail == VIR_DOMAIN_EVENT_UNDEFINED_REMOVED) {
+                pthread_mutex_lock(&lifecycle_mutex);
                 list_remove(thread->dom_list, dom_xml);
+                pthread_mutex_unlock(&lifecycle_mutex);
         }
 
  end:
@@ -579,10 +594,12 @@ static CMPI_THREAD_RETURN lifecycle_thread(void *params)
         if (prefix == NULL)
                 goto init_out;
 
+        pthread_mutex_lock(&lifecycle_mutex);
         conn = connect_by_classname(_BROKER, args->classname, &s);
         if (conn == NULL) {
                 CU_DEBUG("Unable to start lifecycle thread: "
                          "Failed to connect (cn: %s)", args->classname);
+                pthread_mutex_unlock(&lifecycle_mutex);
                 goto conn_out;
         }
 
@@ -594,33 +611,47 @@ static CMPI_THREAD_RETURN lifecycle_thread(void *params)
 
         if (cb_id == -1) {
                 CU_DEBUG("Failed to register domain event watch for '%s'",
-                         args->classname)
+                         args->classname);
+                pthread_mutex_unlock(&lifecycle_mutex);
                 goto cb_out;
         }
 
         CBAttachThread(_BROKER, args->context);
 
         /* Get currently defined domains */
-        if (update_domain_list(conn, thread) != CMPI_RC_OK)
+        if (update_domain_list(conn, thread) != CMPI_RC_OK) {
+                pthread_mutex_unlock(&lifecycle_mutex);
                 goto end;
+        }
 
+        pthread_mutex_unlock(&lifecycle_mutex);
 
         CU_DEBUG("Entering CSI event loop (%s)", prefix);
-        while (thread->active_filters > 0) {
+        while (1) {
+                pthread_mutex_lock(&lifecycle_mutex);
+                if (thread->active_filters <= 0) {
+                        pthread_mutex_unlock(&lifecycle_mutex);
+                        break;
+                }
+                pthread_mutex_unlock(&lifecycle_mutex);
                 if (virEventRunDefaultImpl() < 0) {
                         virErrorPtr err = virGetLastError();
                         CU_DEBUG("Failed to run event loop: %s\n",
                         err && err->message ? err->message : "Unknown error");
                 }
+                usleep(1);
         }
 
         CU_DEBUG("Exiting CSI event loop (%s)", prefix);
 
+        pthread_mutex_lock(&lifecycle_mutex);
         CBDetachThread(_BROKER, args->context);
+        pthread_mutex_unlock(&lifecycle_mutex);
  end:
         virConnectDomainEventDeregisterAny(conn, cb_id);
 
  cb_out:
+        pthread_mutex_lock(&lifecycle_mutex);
 
         thread->id = 0;
         thread->active_filters = 0;
@@ -628,6 +659,8 @@ static CMPI_THREAD_RETURN lifecycle_thread(void *params)
         if (thread->args != NULL)
                 stdi_free_ind_args(&thread->args);
 
+        pthread_mutex_unlock(&lifecycle_mutex);
+
  conn_out:
         virConnectClose(conn);
 
-- 
1.7.1