4 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 only,
8 * as published by the Free Software Foundation.
10 * This program is distributed in the hope that it will be useful, but
11 * WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 * General Public License version 2 for more details (a copy is included
14 * in the LICENSE file that accompanied this code).
16 * You should have received a copy of the GNU General Public License
17 * version 2 along with this program; If not, see
18 * http://www.sun.com/software/products/lustre/docs/GPLv2.pdf
20 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
21 * CA 95054 USA or visit www.sun.com if you need additional information or
27 * Copyright (c) 2002, 2010, Oracle and/or its affiliates. All rights reserved.
28 * Use is subject to license terms.
31 * This file is part of Lustre, http://www.lustre.org/
32 * Lustre is a trademark of Sun Microsystems, Inc.
35 #define DEBUG_SUBSYSTEM S_FILTER
38 #include <linux/module.h>
39 #include <linux/kmod.h>
40 #include <linux/slab.h>
41 #include <linux/libcfs/libcfs.h>
42 #include <lustre_fsfilt.h>
44 LIST_HEAD(fsfilt_types);
46 static struct fsfilt_operations *fsfilt_search_type(const char *type)
48 struct fsfilt_operations *found;
51 list_for_each(p, &fsfilt_types) {
52 found = list_entry(p, struct fsfilt_operations, fs_list);
53 if (!strcmp(found->fs_type, type)) {
60 int fsfilt_register_ops(struct fsfilt_operations *fs_ops)
62 struct fsfilt_operations *found;
64 /* lock fsfilt_types list */
65 if ((found = fsfilt_search_type(fs_ops->fs_type))) {
66 if (found != fs_ops) {
67 CERROR("different operations for type %s\n",
69 /* unlock fsfilt_types list */
73 try_module_get(THIS_MODULE);
74 list_add(&fs_ops->fs_list, &fsfilt_types);
77 /* unlock fsfilt_types list */
80 EXPORT_SYMBOL(fsfilt_register_ops);
82 void fsfilt_unregister_ops(struct fsfilt_operations *fs_ops)
86 /* lock fsfilt_types list */
87 list_for_each(p, &fsfilt_types) {
88 struct fsfilt_operations *found;
90 found = list_entry(p, typeof(*found), fs_list);
91 if (found == fs_ops) {
93 module_put(THIS_MODULE);
97 /* unlock fsfilt_types list */
99 EXPORT_SYMBOL(fsfilt_unregister_ops);
101 struct fsfilt_operations *fsfilt_get_ops(const char *type)
103 struct fsfilt_operations *fs_ops;
105 /* lock fsfilt_types list */
106 if (!(fs_ops = fsfilt_search_type(type))) {
110 snprintf(name, sizeof(name) - 1, "fsfilt_%s", type);
111 name[sizeof(name) - 1] = '\0';
113 if (!(rc = request_module("%s", name))) {
114 fs_ops = fsfilt_search_type(type);
115 CDEBUG(D_INFO, "Loaded module '%s'\n", name);
121 CERROR("Can't find %s interface\n", name);
122 return ERR_PTR(rc < 0 ? rc : -rc);
123 /* unlock fsfilt_types list */
126 try_module_get(fs_ops->fs_owner);
127 /* unlock fsfilt_types list */
131 EXPORT_SYMBOL(fsfilt_get_ops);
133 void fsfilt_put_ops(struct fsfilt_operations *fs_ops)
135 module_put(fs_ops->fs_owner);
137 EXPORT_SYMBOL(fsfilt_put_ops);