LU-12616 obclass: fix MDS start/stop race

[fs/lustre-release.git] / lustre / ldlm / ldlm_plain.c

diff --git a/lustre/ldlm/ldlm_plain.c b/lustre/ldlm/ldlm_plain.c
index 7cdf870..fe27db4 100644 (file)
--- a/lustre/ldlm/ldlm_plain.c
+++ b/lustre/ldlm/ldlm_plain.c
@@ -71,15 +71,17 @@ ldlm_plain_compat_queue(struct list_head *queue, struct ldlm_lock *req,
        enum ldlm_mode req_mode = req->l_req_mode;
        struct ldlm_lock *lock, *next_lock;
        int compat = 1;
-       ENTRY;
 
+       ENTRY;
        lockmode_verify(req_mode);
 
        list_for_each_entry_safe(lock, next_lock, queue, l_res_link) {
 
-               /* We stop walking the queue if we hit ourselves so we don't
+               /*
+                * We stop walking the queue if we hit ourselves so we don't
                 * take conflicting locks enqueued after us into account,
-                * or we'd wait forever. */
+                * or we'd wait forever.
+                */
                if (req == lock)
                        RETURN(compat);
 
@@ -90,30 +92,32 @@ ldlm_plain_compat_queue(struct list_head *queue, struct ldlm_lock *req,
                                       struct ldlm_lock, l_res_link);
 
                if (lockmode_compat(lock->l_req_mode, req_mode))
-                        continue;
+                       continue;
 
-                if (!work_list)
-                        RETURN(0);
+               if (!work_list)
+                       RETURN(0);
 
-                compat = 0;
+               compat = 0;
 
-               /* Add locks of the mode group to \a work_list as
-                * blocking locks for \a req. */
-                if (lock->l_blocking_ast)
-                        ldlm_add_ast_work_item(lock, req, work_list);
+               /*
+                * Add locks of the mode group to \a work_list as
+                * blocking locks for \a req.
+                */
+               if (lock->l_blocking_ast)
+                       ldlm_add_ast_work_item(lock, req, work_list);
 
-                {
+               {
                        struct list_head *head;
 
-                        head = &lock->l_sl_mode;
+                       head = &lock->l_sl_mode;
                        list_for_each_entry(lock, head, l_sl_mode)
-                                if (lock->l_blocking_ast)
-                                        ldlm_add_ast_work_item(lock, req,
-                                                               work_list);
-                }
-        }
+                               if (lock->l_blocking_ast)
+                                       ldlm_add_ast_work_item(lock, req,
+                                                              work_list);
+               }
+       }
 
-        RETURN(compat);
+       RETURN(compat);
 }
 
 /**
@@ -129,50 +133,38 @@ int ldlm_process_plain_lock(struct ldlm_lock *lock, __u64 *flags,
                            enum ldlm_error *err, struct list_head *work_list)
 {
        struct ldlm_resource *res = lock->l_resource;
-       struct list_head rpc_list;
+       struct list_head *grant_work = intention == LDLM_PROCESS_ENQUEUE ?
+                                                       NULL : work_list;
        int rc;
-       ENTRY;
 
-       LASSERT(lock->l_granted_mode != lock->l_req_mode);
+       ENTRY;
+       LASSERT(!ldlm_is_granted(lock));
        check_res_locked(res);
-       LASSERT(list_empty(&res->lr_converting));
-       INIT_LIST_HEAD(&rpc_list);
+       *err = ELDLM_OK;
 
        if (intention == LDLM_PROCESS_RESCAN) {
-                LASSERT(work_list != NULL);
-                rc = ldlm_plain_compat_queue(&res->lr_granted, lock, NULL);
-                if (!rc)
-                        RETURN(LDLM_ITER_STOP);
-                rc = ldlm_plain_compat_queue(&res->lr_waiting, lock, NULL);
-                if (!rc)
-                        RETURN(LDLM_ITER_STOP);
-
-                ldlm_resource_unlink_lock(lock);
-                ldlm_grant_lock(lock, work_list);
-                RETURN(LDLM_ITER_CONTINUE);
-        }
-
-       LASSERT((intention == LDLM_PROCESS_ENQUEUE && work_list == NULL) ||
-               (intention == LDLM_PROCESS_RECOVERY && work_list != NULL));
- restart:
-        rc = ldlm_plain_compat_queue(&res->lr_granted, lock, &rpc_list);
-        rc += ldlm_plain_compat_queue(&res->lr_waiting, lock, &rpc_list);
-
-        if (rc != 2) {
-               rc = ldlm_handle_conflict_lock(lock, flags, &rpc_list, 0);
-               if (rc == -ERESTART)
-                       GOTO(restart, rc);
-               *err = rc;
-       } else {
+               LASSERT(work_list != NULL);
+               rc = ldlm_plain_compat_queue(&res->lr_granted, lock, NULL);
+               if (!rc)
+                       RETURN(LDLM_ITER_STOP);
+               rc = ldlm_plain_compat_queue(&res->lr_waiting, lock, NULL);
+               if (!rc)
+                       RETURN(LDLM_ITER_STOP);
+
                ldlm_resource_unlink_lock(lock);
-               ldlm_grant_lock(lock, work_list);
-               rc = 0;
+               ldlm_grant_lock(lock, grant_work);
+               RETURN(LDLM_ITER_CONTINUE);
        }
 
-       if (!list_empty(&rpc_list))
-               ldlm_discard_bl_list(&rpc_list);
+       rc = ldlm_plain_compat_queue(&res->lr_granted, lock, work_list);
+       rc += ldlm_plain_compat_queue(&res->lr_waiting, lock, work_list);
+
+       if (rc == 2) {
+               ldlm_resource_unlink_lock(lock);
+               ldlm_grant_lock(lock, grant_work);
+       }
 
-       RETURN(rc);
+       RETURN(LDLM_ITER_CONTINUE);
 }
 #endif /* HAVE_SERVER_SUPPORT */