1 /* -*- mode: c; c-basic-offset: 8; indent-tabs-mode: nil; -*-
2 * vim:expandtab:shiftwidth=8:tabstop=8:
4 * Copyright (c) 2002, 2003 Cluster File Systems, Inc.
5 * Author: Peter Braam <braam@clusterfs.com>
6 * Author: Phil Schwan <phil@clusterfs.com>
8 * This file is part of Lustre, http://www.lustre.org.
10 * Lustre is free software; you can redistribute it and/or
11 * modify it under the terms of version 2 of the GNU General Public
12 * License as published by the Free Software Foundation.
14 * Lustre is distributed in the hope that it will be useful,
15 * but WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 * GNU General Public License for more details.
19 * You should have received a copy of the GNU General Public License
20 * along with Lustre; if not, write to the Free Software
21 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
24 #define DEBUG_SUBSYSTEM S_LDLM
27 #include <linux/lustre_dlm.h>
28 #include <linux/obd_support.h>
29 #include <linux/lustre_lib.h>
31 #include <liblustre.h>
34 #include "ldlm_internal.h"
37 ldlm_plain_compat_queue(struct list_head *queue, struct ldlm_lock *req,
40 struct list_head *tmp;
41 struct ldlm_lock *lock;
42 ldlm_mode_t req_mode = req->l_req_mode;
46 list_for_each(tmp, queue) {
47 lock = list_entry(tmp, struct ldlm_lock, l_res_link);
52 if (lockmode_compat(lock->l_req_mode, req_mode))
59 if (lock->l_blocking_ast)
60 ldlm_add_ast_work_item(lock, req, NULL, 0);
66 /* If first_enq is 0 (ie, called from ldlm_reprocess_queue):
67 * - blocking ASTs have already been sent
68 * - the caller has already initialized req->lr_tmp
69 * - must call this function with the ns lock held
71 * If first_enq is 1 (ie, called from ldlm_lock_enqueue):
72 * - blocking ASTs have not been sent
73 * - the caller has NOT initialized req->lr_tmp, so we must
74 * - must call this function with the ns lock held once */
75 int ldlm_process_plain_lock(struct ldlm_lock *lock, int *flags, int first_enq,
78 struct ldlm_resource *res = lock->l_resource;
79 struct list_head rpc_list = LIST_HEAD_INIT(rpc_list);
83 LASSERT(list_empty(&res->lr_converting));
86 LASSERT(res->lr_tmp != NULL);
87 rc = ldlm_plain_compat_queue(&res->lr_granted, lock, 0);
89 RETURN(LDLM_ITER_STOP);
90 rc = ldlm_plain_compat_queue(&res->lr_waiting, lock, 0);
92 RETURN(LDLM_ITER_STOP);
94 ldlm_resource_unlink_lock(lock);
95 ldlm_grant_lock(lock, NULL, 0, 1);
96 RETURN(LDLM_ITER_CONTINUE);
100 LASSERT(res->lr_tmp == NULL);
101 res->lr_tmp = &rpc_list;
102 rc = ldlm_plain_compat_queue(&res->lr_granted, lock, 1);
103 rc += ldlm_plain_compat_queue(&res->lr_waiting, lock, 1);
107 /* If either of the compat_queue()s returned 0, then we
108 * have ASTs to send and must go onto the waiting list.
110 * bug 2322: we used to unlink and re-add here, which was a
111 * terrible folly -- if we goto restart, we could get
112 * re-ordered! Causes deadlock, because ASTs aren't sent! */
113 if (list_empty(&lock->l_res_link))
114 ldlm_resource_add_lock(res, &res->lr_waiting, lock);
115 l_unlock(&res->lr_namespace->ns_lock);
116 rc = ldlm_run_ast_work(res->lr_namespace, &rpc_list);
117 l_lock(&res->lr_namespace->ns_lock);
119 GOTO(restart, -ERESTART);
120 *flags |= LDLM_FL_BLOCK_GRANTED;
122 ldlm_resource_unlink_lock(lock);
123 ldlm_grant_lock(lock, NULL, 0, 0);