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 the Lustre file system, http://www.lustre.org
9 * Lustre is a trademark of Cluster File Systems, Inc.
11 * You may have signed or agreed to another license before downloading
12 * this software. If so, you are bound by the terms and conditions
13 * of that agreement, and the following does not apply to you. See the
14 * LICENSE file included with this distribution for more information.
16 * If you did not agree to a different license, then this copy of Lustre
17 * is open source software; you can redistribute it and/or modify it
18 * under the terms of version 2 of the GNU General Public License as
19 * published by the Free Software Foundation.
21 * In either case, Lustre is distributed in the hope that it will be
22 * useful, but WITHOUT ANY WARRANTY; without even the implied warranty
23 * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
24 * license text for more details.
27 #define DEBUG_SUBSYSTEM S_LDLM
30 #include <linux/lustre_dlm.h>
31 #include <linux/obd_support.h>
32 #include <linux/lustre_lib.h>
34 #include <liblustre.h>
37 #include "ldlm_internal.h"
40 ldlm_plain_compat_queue(struct list_head *queue, struct ldlm_lock *req,
43 struct list_head *tmp;
44 struct ldlm_lock *lock;
45 ldlm_mode_t req_mode = req->l_req_mode;
49 lockmode_verify(req_mode);
51 list_for_each(tmp, queue) {
52 lock = list_entry(tmp, struct ldlm_lock, l_res_link);
57 if (lockmode_compat(lock->l_req_mode, req_mode))
64 if (lock->l_blocking_ast)
65 ldlm_add_ast_work_item(lock, req, NULL, 0);
71 /* If first_enq is 0 (ie, called from ldlm_reprocess_queue):
72 * - blocking ASTs have already been sent
73 * - the caller has already initialized req->lr_tmp
74 * - must call this function with the ns lock held
76 * If first_enq is 1 (ie, called from ldlm_lock_enqueue):
77 * - blocking ASTs have not been sent
78 * - the caller has NOT initialized req->lr_tmp, so we must
79 * - must call this function with the ns lock held once */
80 int ldlm_process_plain_lock(struct ldlm_lock *lock, int *flags, int first_enq,
83 struct ldlm_resource *res = lock->l_resource;
84 struct list_head rpc_list = LIST_HEAD_INIT(rpc_list);
88 LASSERT(list_empty(&res->lr_converting));
91 LASSERT(res->lr_tmp != NULL);
92 rc = ldlm_plain_compat_queue(&res->lr_granted, lock, 0);
94 RETURN(LDLM_ITER_STOP);
95 rc = ldlm_plain_compat_queue(&res->lr_waiting, lock, 0);
97 RETURN(LDLM_ITER_STOP);
99 ldlm_resource_unlink_lock(lock);
100 ldlm_grant_lock(lock, NULL, 0, 1);
101 RETURN(LDLM_ITER_CONTINUE);
105 LASSERT(res->lr_tmp == NULL);
106 res->lr_tmp = &rpc_list;
107 rc = ldlm_plain_compat_queue(&res->lr_granted, lock, 1);
108 rc += ldlm_plain_compat_queue(&res->lr_waiting, lock, 1);
112 /* If either of the compat_queue()s returned 0, then we
113 * have ASTs to send and must go onto the waiting list.
115 * bug 2322: we used to unlink and re-add here, which was a
116 * terrible folly -- if we goto restart, we could get
117 * re-ordered! Causes deadlock, because ASTs aren't sent! */
118 if (list_empty(&lock->l_res_link))
119 ldlm_resource_add_lock(res, &res->lr_waiting, lock);
120 l_unlock(&res->lr_namespace->ns_lock);
121 rc = ldlm_run_ast_work(res->lr_namespace, &rpc_list);
122 l_lock(&res->lr_namespace->ns_lock);
124 GOTO(restart, -ERESTART);
125 *flags |= LDLM_FL_BLOCK_GRANTED;
127 ldlm_resource_unlink_lock(lock);
128 ldlm_grant_lock(lock, NULL, 0, 0);