Whamcloud - gitweb
LU-1166 recovery: don't leak a connected client counter.
[fs/lustre-release.git] / lustre / obdclass / genops.c
index 9a9adfa..ce151fa 100644 (file)
@@ -28,6 +28,8 @@
 /*
  * Copyright (c) 1999, 2010, Oracle and/or its affiliates. All rights reserved.
  * Use is subject to license terms.
+ *
+ * Copyright (c) 2011, 2012, Whamcloud, Inc.
  */
 /*
  * This file is part of Lustre, http://www.lustre.org/
@@ -136,6 +138,7 @@ struct obd_type *class_get_type(const char *name)
         }
         return type;
 }
+EXPORT_SYMBOL(class_get_type);
 
 void class_put_type(struct obd_type *type)
 {
@@ -145,6 +148,7 @@ void class_put_type(struct obd_type *type)
         cfs_module_put(type->typ_dt_ops->o_owner);
         cfs_spin_unlock(&type->obd_type_lock);
 }
+EXPORT_SYMBOL(class_put_type);
 
 #define CLASS_MAX_NAME 1024
 
@@ -217,6 +221,7 @@ int class_register_type(struct obd_ops *dt_ops, struct md_ops *md_ops,
         OBD_FREE(type, sizeof(*type));
         RETURN(rc);
 }
+EXPORT_SYMBOL(class_register_type);
 
 int class_unregister_type(const char *name)
 {
@@ -255,6 +260,7 @@ int class_unregister_type(const char *name)
         OBD_FREE(type, sizeof(*type));
         RETURN(0);
 } /* class_unregister_type */
+EXPORT_SYMBOL(class_unregister_type);
 
 /**
  * Create a new obd device.
@@ -274,6 +280,7 @@ struct obd_device *class_newdev(const char *type_name, const char *name)
         struct obd_type *type = NULL;
         int i;
         int new_obd_minor = 0;
+        ENTRY;
 
         if (strlen(name) >= MAX_OBD_NAME) {
                 CERROR("name/uuid must be < %u bytes long\n", MAX_OBD_NAME);
@@ -293,12 +300,14 @@ struct obd_device *class_newdev(const char *type_name, const char *name)
         }
         LASSERT(newdev->obd_magic == OBD_DEVICE_MAGIC);
 
-        cfs_spin_lock(&obd_dev_lock);
+        cfs_write_lock(&obd_dev_lock);
         for (i = 0; i < class_devno_max(); i++) {
                 struct obd_device *obd = class_num2obd(i);
+
                 if (obd && obd->obd_name &&
                     (strcmp(name, obd->obd_name) == 0)) {
-                        CERROR("Device %s already exists, won't add\n", name);
+                        CERROR("Device %s already exists at %d, won't add\n",
+                               name, i);
                         if (result) {
                                 LASSERTF(result->obd_magic == OBD_DEVICE_MAGIC,
                                          "%p obd_magic %08x != %08x\n", result,
@@ -323,12 +332,12 @@ struct obd_device *class_newdev(const char *type_name, const char *name)
                         obd_devs[i] = result;
                 }
         }
-        cfs_spin_unlock(&obd_dev_lock);
+        cfs_write_unlock(&obd_dev_lock);
 
         if (result == NULL && i >= class_devno_max()) {
                 CERROR("all %u OBD devices used, increase MAX_OBD_DEVICES\n",
                        class_devno_max());
-                result = ERR_PTR(-EOVERFLOW);
+                RETURN(ERR_PTR(-EOVERFLOW));
         }
 
         if (IS_ERR(result)) {
@@ -338,7 +347,7 @@ struct obd_device *class_newdev(const char *type_name, const char *name)
                 CDEBUG(D_IOCTL, "Adding new device %s (%p)\n",
                        result->obd_name, result);
         }
-        return result;
+        RETURN(result);
 }
 
 void class_release_dev(struct obd_device *obd)
@@ -351,12 +360,12 @@ void class_release_dev(struct obd_device *obd)
                  obd, obd->obd_minor, obd_devs[obd->obd_minor]);
         LASSERT(obd_type != NULL);
 
-        CDEBUG(D_INFO, "Release obd device %s obd_type name =%s\n",
-               obd->obd_name,obd->obd_type->typ_name);
+        CDEBUG(D_INFO, "Release obd device %s at %d obd_type name =%s\n",
+               obd->obd_name, obd->obd_minor, obd->obd_type->typ_name);
 
-        cfs_spin_lock(&obd_dev_lock);
+        cfs_write_lock(&obd_dev_lock);
         obd_devs[obd->obd_minor] = NULL;
-        cfs_spin_unlock(&obd_dev_lock);
+        cfs_write_unlock(&obd_dev_lock);
         obd_device_free(obd);
 
         class_put_type(obd_type);
@@ -369,24 +378,26 @@ int class_name2dev(const char *name)
         if (!name)
                 return -1;
 
-        cfs_spin_lock(&obd_dev_lock);
+        cfs_read_lock(&obd_dev_lock);
         for (i = 0; i < class_devno_max(); i++) {
                 struct obd_device *obd = class_num2obd(i);
+
                 if (obd && obd->obd_name && strcmp(name, obd->obd_name) == 0) {
                         /* Make sure we finished attaching before we give
                            out any references */
                         LASSERT(obd->obd_magic == OBD_DEVICE_MAGIC);
                         if (obd->obd_attached) {
-                                cfs_spin_unlock(&obd_dev_lock);
+                                cfs_read_unlock(&obd_dev_lock);
                                 return i;
                         }
                         break;
                 }
         }
-        cfs_spin_unlock(&obd_dev_lock);
+        cfs_read_unlock(&obd_dev_lock);
 
         return -1;
 }
+EXPORT_SYMBOL(class_name2dev);
 
 struct obd_device *class_name2obd(const char *name)
 {
@@ -396,24 +407,27 @@ struct obd_device *class_name2obd(const char *name)
                 return NULL;
         return class_num2obd(dev);
 }
+EXPORT_SYMBOL(class_name2obd);
 
 int class_uuid2dev(struct obd_uuid *uuid)
 {
         int i;
 
-        cfs_spin_lock(&obd_dev_lock);
+        cfs_read_lock(&obd_dev_lock);
         for (i = 0; i < class_devno_max(); i++) {
                 struct obd_device *obd = class_num2obd(i);
+
                 if (obd && obd_uuid_equals(uuid, &obd->obd_uuid)) {
                         LASSERT(obd->obd_magic == OBD_DEVICE_MAGIC);
-                        cfs_spin_unlock(&obd_dev_lock);
+                        cfs_read_unlock(&obd_dev_lock);
                         return i;
                 }
         }
-        cfs_spin_unlock(&obd_dev_lock);
+        cfs_read_unlock(&obd_dev_lock);
 
         return -1;
 }
+EXPORT_SYMBOL(class_uuid2dev);
 
 struct obd_device *class_uuid2obd(struct obd_uuid *uuid)
 {
@@ -422,6 +436,7 @@ struct obd_device *class_uuid2obd(struct obd_uuid *uuid)
                 return NULL;
         return class_num2obd(dev);
 }
+EXPORT_SYMBOL(class_uuid2obd);
 
 /**
  * Get obd device from ::obd_devs[]
@@ -450,15 +465,17 @@ struct obd_device *class_num2obd(int num)
 
         return obd;
 }
+EXPORT_SYMBOL(class_num2obd);
 
 void class_obd_list(void)
 {
         char *status;
         int i;
 
-        cfs_spin_lock(&obd_dev_lock);
+        cfs_read_lock(&obd_dev_lock);
         for (i = 0; i < class_devno_max(); i++) {
                 struct obd_device *obd = class_num2obd(i);
+
                 if (obd == NULL)
                         continue;
                 if (obd->obd_stopping)
@@ -474,7 +491,7 @@ void class_obd_list(void)
                          obd->obd_name, obd->obd_uuid.uuid,
                          cfs_atomic_read(&obd->obd_refcount));
         }
-        cfs_spin_unlock(&obd_dev_lock);
+        cfs_read_unlock(&obd_dev_lock);
         return;
 }
 
@@ -487,9 +504,10 @@ struct obd_device * class_find_client_obd(struct obd_uuid *tgt_uuid,
 {
         int i;
 
-        cfs_spin_lock(&obd_dev_lock);
+        cfs_read_lock(&obd_dev_lock);
         for (i = 0; i < class_devno_max(); i++) {
                 struct obd_device *obd = class_num2obd(i);
+
                 if (obd == NULL)
                         continue;
                 if ((strncmp(obd->obd_type->typ_name, typ_name,
@@ -498,15 +516,16 @@ struct obd_device * class_find_client_obd(struct obd_uuid *tgt_uuid,
                                             &obd->u.cli.cl_target_uuid) &&
                             ((grp_uuid)? obd_uuid_equals(grp_uuid,
                                                          &obd->obd_uuid) : 1)) {
-                                cfs_spin_unlock(&obd_dev_lock);
+                                cfs_read_unlock(&obd_dev_lock);
                                 return obd;
                         }
                 }
         }
-        cfs_spin_unlock(&obd_dev_lock);
+        cfs_read_unlock(&obd_dev_lock);
 
         return NULL;
 }
+EXPORT_SYMBOL(class_find_client_obd);
 
 /* Iterate the obd_device list looking devices have grp_uuid. Start
    searching at *next, and if a device is found, the next index to look
@@ -523,22 +542,24 @@ struct obd_device * class_devices_in_group(struct obd_uuid *grp_uuid, int *next)
         else
                 return NULL;
 
-        cfs_spin_lock(&obd_dev_lock);
+        cfs_read_lock(&obd_dev_lock);
         for (; i < class_devno_max(); i++) {
                 struct obd_device *obd = class_num2obd(i);
+
                 if (obd == NULL)
                         continue;
                 if (obd_uuid_equals(grp_uuid, &obd->obd_uuid)) {
                         if (next != NULL)
                                 *next = i+1;
-                        cfs_spin_unlock(&obd_dev_lock);
+                        cfs_read_unlock(&obd_dev_lock);
                         return obd;
                 }
         }
-        cfs_spin_unlock(&obd_dev_lock);
+        cfs_read_unlock(&obd_dev_lock);
 
         return NULL;
 }
+EXPORT_SYMBOL(class_devices_in_group);
 
 /**
  * to notify sptlrpc log for \a fsname has changed, let every relevant OBD
@@ -552,7 +573,7 @@ int class_notify_sptlrpc_conf(const char *fsname, int namelen)
 
         LASSERT(namelen > 0);
 
-        cfs_spin_lock(&obd_dev_lock);
+        cfs_read_lock(&obd_dev_lock);
         for (i = 0; i < class_devno_max(); i++) {
                 obd = class_num2obd(i);
 
@@ -571,15 +592,15 @@ int class_notify_sptlrpc_conf(const char *fsname, int namelen)
                         continue;
 
                 class_incref(obd, __FUNCTION__, obd);
-                cfs_spin_unlock(&obd_dev_lock);
+                cfs_read_unlock(&obd_dev_lock);
                 rc2 = obd_set_info_async(obd->obd_self_export,
                                          sizeof(KEY_SPTLRPC_CONF),
                                          KEY_SPTLRPC_CONF, 0, NULL, NULL);
                 rc = rc ? rc : rc2;
                 class_decref(obd, __FUNCTION__, obd);
-                cfs_spin_lock(&obd_dev_lock);
+                cfs_read_lock(&obd_dev_lock);
         }
-        cfs_spin_unlock(&obd_dev_lock);
+        cfs_read_unlock(&obd_dev_lock);
         return rc;
 }
 EXPORT_SYMBOL(class_notify_sptlrpc_conf);
@@ -669,6 +690,7 @@ struct obd_export *class_conn2export(struct lustre_handle *conn)
         export = class_handle2object(conn->cookie);
         RETURN(export);
 }
+EXPORT_SYMBOL(class_conn2export);
 
 struct obd_device *class_exp2obd(struct obd_export *exp)
 {
@@ -676,6 +698,7 @@ struct obd_device *class_exp2obd(struct obd_export *exp)
                 return exp->exp_obd;
         return NULL;
 }
+EXPORT_SYMBOL(class_exp2obd);
 
 struct obd_device *class_conn2obd(struct lustre_handle *conn)
 {
@@ -688,6 +711,7 @@ struct obd_device *class_conn2obd(struct lustre_handle *conn)
         }
         return NULL;
 }
+EXPORT_SYMBOL(class_conn2obd);
 
 struct obd_import *class_exp2cliimp(struct obd_export *exp)
 {
@@ -696,6 +720,7 @@ struct obd_import *class_exp2cliimp(struct obd_export *exp)
                 return NULL;
         return obd->u.cli.cl_import;
 }
+EXPORT_SYMBOL(class_exp2cliimp);
 
 struct obd_import *class_conn2cliimp(struct lustre_handle *conn)
 {
@@ -704,19 +729,55 @@ struct obd_import *class_conn2cliimp(struct lustre_handle *conn)
                 return NULL;
         return obd->u.cli.cl_import;
 }
+EXPORT_SYMBOL(class_conn2cliimp);
 
 /* Export management functions */
+
+/* if export is involved in recovery then clean up related things */
+void class_export_recovery_cleanup(struct obd_export *exp)
+{
+        struct obd_device *obd = exp->exp_obd;
+
+        cfs_spin_lock(&obd->obd_recovery_task_lock);
+        if (exp->exp_delayed)
+                obd->obd_delayed_clients--;
+        if (obd->obd_recovering && exp->exp_in_recovery) {
+                cfs_spin_lock(&exp->exp_lock);
+                exp->exp_in_recovery = 0;
+                cfs_spin_unlock(&exp->exp_lock);
+                LASSERT_ATOMIC_POS(&obd->obd_connected_clients);
+                cfs_atomic_dec(&obd->obd_connected_clients);
+        }
+        cfs_spin_unlock(&obd->obd_recovery_task_lock);
+        /** Cleanup req replay fields */
+        if (exp->exp_req_replay_needed) {
+                cfs_spin_lock(&exp->exp_lock);
+                exp->exp_req_replay_needed = 0;
+                cfs_spin_unlock(&exp->exp_lock);
+                LASSERT(cfs_atomic_read(&obd->obd_req_replay_clients));
+                cfs_atomic_dec(&obd->obd_req_replay_clients);
+        }
+        /** Cleanup lock replay data */
+        if (exp->exp_lock_replay_needed) {
+                cfs_spin_lock(&exp->exp_lock);
+                exp->exp_lock_replay_needed = 0;
+                cfs_spin_unlock(&exp->exp_lock);
+                LASSERT(cfs_atomic_read(&obd->obd_lock_replay_clients));
+                cfs_atomic_dec(&obd->obd_lock_replay_clients);
+        }
+}
+
 static void class_export_destroy(struct obd_export *exp)
 {
         struct obd_device *obd = exp->exp_obd;
         ENTRY;
 
         LASSERT_ATOMIC_ZERO(&exp->exp_refcount);
+        LASSERT(obd != NULL);
 
         CDEBUG(D_IOCTL, "destroying export %p/%s for %s\n", exp,
                exp->exp_client_uuid.uuid, obd->obd_name);
 
-        LASSERT(obd != NULL);
 
         /* "Local" exports (lctl, LOV->{mdc,osc}) have no connection. */
         if (exp->exp_connection)
@@ -725,7 +786,7 @@ static void class_export_destroy(struct obd_export *exp)
         LASSERT(cfs_list_empty(&exp->exp_outstanding_replies));
         LASSERT(cfs_list_empty(&exp->exp_uncommitted_replies));
         LASSERT(cfs_list_empty(&exp->exp_req_replay_queue));
-        LASSERT(cfs_list_empty(&exp->exp_queued_rpc));
+        LASSERT(cfs_list_empty(&exp->exp_hp_rpcs));
         obd_destroy_export(exp);
         class_decref(obd, "export", exp);
 
@@ -750,7 +811,7 @@ EXPORT_SYMBOL(class_export_get);
 void class_export_put(struct obd_export *exp)
 {
         LASSERT(exp != NULL);
-        LASSERT_ATOMIC_GT_LT(&exp->exp_refcount, 0, 0x5a5a5a);
+        LASSERT_ATOMIC_GT_LT(&exp->exp_refcount, 0, LI_POISON);
         CDEBUG(D_INFO, "PUTting export %p : new refcount %d\n", exp,
                cfs_atomic_read(&exp->exp_refcount) - 1);
 
@@ -761,6 +822,7 @@ void class_export_put(struct obd_export *exp)
 
                 /* release nid stat refererence */
                 lprocfs_exp_cleanup(exp);
+                class_export_recovery_cleanup(exp);
 
                 obd_zombie_export_add(exp);
         }
@@ -799,13 +861,15 @@ struct obd_export *class_new_export(struct obd_device *obd,
         CFS_INIT_LIST_HEAD(&export->exp_uncommitted_replies);
         CFS_INIT_LIST_HEAD(&export->exp_req_replay_queue);
         CFS_INIT_LIST_HEAD(&export->exp_handle.h_link);
-        CFS_INIT_LIST_HEAD(&export->exp_queued_rpc);
+        CFS_INIT_LIST_HEAD(&export->exp_hp_rpcs);
         class_handle_hash(&export->exp_handle, export_handle_addref);
         export->exp_last_request_time = cfs_time_current_sec();
         cfs_spin_lock_init(&export->exp_lock);
         cfs_spin_lock_init(&export->exp_rpc_lock);
         CFS_INIT_HLIST_NODE(&export->exp_uuid_hash);
         CFS_INIT_HLIST_NODE(&export->exp_nid_hash);
+        cfs_spin_lock_init(&export->exp_bl_list_lock);
+        CFS_INIT_LIST_HEAD(&export->exp_bl_list);
 
         export->exp_sp_peer = LUSTRE_SP_ANY;
         export->exp_flvr.sf_rpc = SPTLRPC_FLVR_INVALID;
@@ -926,7 +990,7 @@ void class_import_put(struct obd_import *imp)
         ENTRY;
 
         LASSERT(cfs_list_empty(&imp->imp_zombie_chain));
-        LASSERT_ATOMIC_GE_LT(&imp->imp_refcount, 0, 0x5a5a5a);
+        LASSERT_ATOMIC_GT_LT(&imp->imp_refcount, 0, LI_POISON);
 
         CDEBUG(D_INFO, "import %p refcount=%d obd=%s\n", imp,
                cfs_atomic_read(&imp->imp_refcount) - 1,
@@ -969,7 +1033,7 @@ struct obd_import *class_new_import(struct obd_device *obd)
         imp->imp_last_success_conn = 0;
         imp->imp_state = LUSTRE_IMP_NEW;
         imp->imp_obd = class_incref(obd, "import", imp);
-        cfs_sema_init(&imp->imp_sec_mutex, 1);
+        cfs_mutex_init(&imp->imp_sec_mutex);
         cfs_waitq_init(&imp->imp_recovery_waitq);
 
         cfs_atomic_set(&imp->imp_refcount, 2);
@@ -1073,39 +1137,6 @@ int class_connect(struct lustre_handle *conn, struct obd_device *obd,
 }
 EXPORT_SYMBOL(class_connect);
 
-/* if export is involved in recovery then clean up related things */
-void class_export_recovery_cleanup(struct obd_export *exp)
-{
-        struct obd_device *obd = exp->exp_obd;
-
-        cfs_spin_lock(&obd->obd_recovery_task_lock);
-        if (exp->exp_delayed)
-                obd->obd_delayed_clients--;
-        if (obd->obd_recovering && exp->exp_in_recovery) {
-                cfs_spin_lock(&exp->exp_lock);
-                exp->exp_in_recovery = 0;
-                cfs_spin_unlock(&exp->exp_lock);
-                LASSERT(obd->obd_connected_clients);
-                obd->obd_connected_clients--;
-        }
-        cfs_spin_unlock(&obd->obd_recovery_task_lock);
-        /** Cleanup req replay fields */
-        if (exp->exp_req_replay_needed) {
-                cfs_spin_lock(&exp->exp_lock);
-                exp->exp_req_replay_needed = 0;
-                cfs_spin_unlock(&exp->exp_lock);
-                LASSERT(cfs_atomic_read(&obd->obd_req_replay_clients));
-                cfs_atomic_dec(&obd->obd_req_replay_clients);
-        }
-        /** Cleanup lock replay data */
-        if (exp->exp_lock_replay_needed) {
-                cfs_spin_lock(&exp->exp_lock);
-                exp->exp_lock_replay_needed = 0;
-                cfs_spin_unlock(&exp->exp_lock);
-                LASSERT(cfs_atomic_read(&obd->obd_lock_replay_clients));
-                cfs_atomic_dec(&obd->obd_lock_replay_clients);
-        }
-}
 
 /* This function removes 1-3 references from the export:
  * 1 - for export pointer passed
@@ -1119,8 +1150,7 @@ int class_disconnect(struct obd_export *export)
         ENTRY;
 
         if (export == NULL) {
-                fixme();
-                CDEBUG(D_IOCTL, "attempting to free NULL export %p\n", export);
+                CWARN("attempting to free NULL export %p\n", export);
                 RETURN(-EINVAL);
         }
 
@@ -1145,12 +1175,12 @@ int class_disconnect(struct obd_export *export)
                              &export->exp_connection->c_peer.nid,
                              &export->exp_nid_hash);
 
-        class_export_recovery_cleanup(export);
         class_unlink_export(export);
 no_disconn:
         class_export_put(export);
         RETURN(0);
 }
+EXPORT_SYMBOL(class_disconnect);
 
 /* Return non-zero for a fully connected export */
 int class_connected_export(struct obd_export *exp)
@@ -1250,15 +1280,25 @@ void class_disconnect_stale_exports(struct obd_device *obd,
         CFS_INIT_LIST_HEAD(&work_list);
         cfs_spin_lock(&obd->obd_dev_lock);
         cfs_list_for_each_safe(pos, n, &obd->obd_exports) {
+                int failed;
+
                 exp = cfs_list_entry(pos, struct obd_export, exp_obd_chain);
-                if (test_export(exp))
-                        continue;
 
                 /* don't count self-export as client */
                 if (obd_uuid_equals(&exp->exp_client_uuid,
                                     &exp->exp_obd->obd_uuid))
                         continue;
 
+                if (test_export(exp))
+                        continue;
+
+                cfs_spin_lock(&exp->exp_lock);
+                failed = exp->exp_failed;
+                exp->exp_failed = 1;
+                cfs_spin_unlock(&exp->exp_lock);
+                if (failed)
+                        continue;
+
                 cfs_list_move(&exp->exp_obd_chain, &work_list);
                 evicted++;
                 CDEBUG(D_ERROR, "%s: disconnect stale client %s@%s\n",
@@ -1301,6 +1341,9 @@ void class_fail_export(struct obd_export *exp)
         if (obd_dump_on_timeout)
                 libcfs_debug_dumplog();
 
+        /* need for safe call CDEBUG after obd_disconnect */
+        class_export_get(exp);
+
         /* Most callers into obd_disconnect are removing their own reference
          * (request, for example) in addition to the one from the hash table.
          * We don't have such a reference here, so make one. */
@@ -1311,6 +1354,7 @@ void class_fail_export(struct obd_export *exp)
         else
                 CDEBUG(D_HA, "disconnected export %p/%s\n",
                        exp, exp->exp_client_uuid.uuid);
+        class_export_put(exp);
 }
 EXPORT_SYMBOL(class_fail_export);
 
@@ -1464,6 +1508,9 @@ void obd_exports_barrier(struct obd_device *obd)
 }
 EXPORT_SYMBOL(obd_exports_barrier);
 
+/* Total amount of zombies to be destroyed */
+static int zombies_count = 0;
+
 /**
  * kill zombie imports and exports
  */
@@ -1494,11 +1541,19 @@ void obd_zombie_impexp_cull(void)
 
                 cfs_spin_unlock(&obd_zombie_impexp_lock);
 
-                if (import != NULL)
+                if (import != NULL) {
                         class_import_destroy(import);
+                        cfs_spin_lock(&obd_zombie_impexp_lock);
+                        zombies_count--;
+                        cfs_spin_unlock(&obd_zombie_impexp_lock);
+                }
 
-                if (export != NULL)
+                if (export != NULL) {
                         class_export_destroy(export);
+                        cfs_spin_lock(&obd_zombie_impexp_lock);
+                        zombies_count--;
+                        cfs_spin_unlock(&obd_zombie_impexp_lock);
+                }
 
                 cfs_cond_resched();
         } while (import != NULL || export != NULL);
@@ -1523,10 +1578,8 @@ static int obd_zombie_impexp_check(void *arg)
         int rc;
 
         cfs_spin_lock(&obd_zombie_impexp_lock);
-        rc = cfs_list_empty(&obd_zombie_imports) &&
-             cfs_list_empty(&obd_zombie_exports) &&
+        rc = (zombies_count == 0) &&
              !cfs_test_bit(OBD_ZOMBIE_STOP, &obd_zombie_flags);
-
         cfs_spin_unlock(&obd_zombie_impexp_lock);
 
         RETURN(rc);
@@ -1541,11 +1594,11 @@ static void obd_zombie_export_add(struct obd_export *exp) {
         cfs_list_del_init(&exp->exp_obd_chain);
         cfs_spin_unlock(&exp->exp_obd->obd_dev_lock);
         cfs_spin_lock(&obd_zombie_impexp_lock);
+        zombies_count++;
         cfs_list_add(&exp->exp_obd_chain, &obd_zombie_exports);
         cfs_spin_unlock(&obd_zombie_impexp_lock);
 
-        if (obd_zombie_impexp_notify != NULL)
-                obd_zombie_impexp_notify();
+        obd_zombie_impexp_notify();
 }
 
 /**
@@ -1555,11 +1608,11 @@ static void obd_zombie_import_add(struct obd_import *imp) {
         LASSERT(imp->imp_sec == NULL);
         cfs_spin_lock(&obd_zombie_impexp_lock);
         LASSERT(cfs_list_empty(&imp->imp_zombie_chain));
+        zombies_count++;
         cfs_list_add(&imp->imp_zombie_chain, &obd_zombie_imports);
         cfs_spin_unlock(&obd_zombie_impexp_lock);
 
-        if (obd_zombie_impexp_notify != NULL)
-                obd_zombie_impexp_notify();
+        obd_zombie_impexp_notify();
 }
 
 /**
@@ -1567,7 +1620,12 @@ static void obd_zombie_import_add(struct obd_import *imp) {
  */
 static void obd_zombie_impexp_notify(void)
 {
-        cfs_waitq_signal(&obd_zombie_waitq);
+        /*
+         * Make sure obd_zomebie_impexp_thread get this notification.
+         * It is possible this signal only get by obd_zombie_barrier, and
+         * barrier gulps this notification and sleeps away and hangs ensues
+         */
+        cfs_waitq_broadcast(&obd_zombie_waitq);
 }
 
 /**
@@ -1579,8 +1637,7 @@ static int obd_zombie_is_idle(void)
 
         LASSERT(!cfs_test_bit(OBD_ZOMBIE_STOP, &obd_zombie_flags));
         cfs_spin_lock(&obd_zombie_impexp_lock);
-        rc = cfs_list_empty(&obd_zombie_imports) &&
-             cfs_list_empty(&obd_zombie_exports);
+        rc = (zombies_count == 0);
         cfs_spin_unlock(&obd_zombie_impexp_lock);
         return rc;
 }
@@ -1672,7 +1729,7 @@ int obd_zombie_impexp_init(void)
         obd_zombie_pid = 0;
 
 #ifdef __KERNEL__
-        rc = cfs_kernel_thread(obd_zombie_impexp_thread, NULL, 0);
+        rc = cfs_create_thread(obd_zombie_impexp_thread, NULL, 0);
         if (rc < 0)
                 RETURN(rc);