2 * Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved.
3 * Copyright (C) 2004-2006 Red Hat, Inc. All rights reserved.
5 * This copyrighted material is made available to anyone wishing to use,
6 * modify, copy, or redistribute it subject to the terms and conditions
7 * of the GNU General Public License version 2.
10 #include <linux/module.h>
11 #include <linux/init.h>
12 #include <linux/string.h>
13 #include <linux/slab.h>
14 #include <linux/wait.h>
15 #include <linux/sched.h>
16 #include <linux/kmod.h>
18 #include <linux/delay.h>
19 #include <linux/lm_interface.h>
22 struct list_head lw_list;
23 const struct lm_lockops *lw_ops;
26 static int nolock_mount(char *table_name, char *host_data,
27 lm_callback_t cb, void *cb_data,
28 unsigned int min_lvb_size, int flags,
29 struct lm_lockstruct *lockstruct,
30 struct kobject *fskobj);
32 /* List of registered low-level locking protocols. A file system selects one
33 of them by name at mount time, e.g. lock_nolock, lock_dlm. */
35 static const struct lm_lockops nolock_ops = {
36 .lm_proto_name = "lock_nolock",
37 .lm_mount = nolock_mount,
40 static struct lmh_wrapper nolock_proto = {
41 .lw_list = LIST_HEAD_INIT(nolock_proto.lw_list),
42 .lw_ops = &nolock_ops,
45 static LIST_HEAD(lmh_list);
46 static DEFINE_MUTEX(lmh_lock);
48 static int nolock_mount(char *table_name, char *host_data,
49 lm_callback_t cb, void *cb_data,
50 unsigned int min_lvb_size, int flags,
51 struct lm_lockstruct *lockstruct,
52 struct kobject *fskobj)
57 c = strstr(host_data, "jid=");
62 sscanf(c, "%u", &jid);
65 lockstruct->ls_jid = jid;
66 lockstruct->ls_first = 1;
67 lockstruct->ls_lvb_size = min_lvb_size;
68 lockstruct->ls_ops = &nolock_ops;
69 lockstruct->ls_flags = LM_LSFLAG_LOCAL;
75 * gfs2_register_lockproto - Register a low-level locking protocol
76 * @proto: the protocol definition
78 * Returns: 0 on success, -EXXX on failure
81 int gfs2_register_lockproto(const struct lm_lockops *proto)
83 struct lmh_wrapper *lw;
85 mutex_lock(&lmh_lock);
87 list_for_each_entry(lw, &lmh_list, lw_list) {
88 if (!strcmp(lw->lw_ops->lm_proto_name, proto->lm_proto_name)) {
89 mutex_unlock(&lmh_lock);
90 printk(KERN_INFO "GFS2: protocol %s already exists\n",
91 proto->lm_proto_name);
96 lw = kzalloc(sizeof(struct lmh_wrapper), GFP_KERNEL);
98 mutex_unlock(&lmh_lock);
103 list_add(&lw->lw_list, &lmh_list);
105 mutex_unlock(&lmh_lock);
111 * gfs2_unregister_lockproto - Unregister a low-level locking protocol
112 * @proto: the protocol definition
116 void gfs2_unregister_lockproto(const struct lm_lockops *proto)
118 struct lmh_wrapper *lw;
120 mutex_lock(&lmh_lock);
122 list_for_each_entry(lw, &lmh_list, lw_list) {
123 if (!strcmp(lw->lw_ops->lm_proto_name, proto->lm_proto_name)) {
124 list_del(&lw->lw_list);
125 mutex_unlock(&lmh_lock);
131 mutex_unlock(&lmh_lock);
133 printk(KERN_WARNING "GFS2: can't unregister lock protocol %s\n",
134 proto->lm_proto_name);
138 * gfs2_mount_lockproto - Mount a lock protocol
139 * @proto_name - the name of the protocol
140 * @table_name - the name of the lock space
141 * @host_data - data specific to this host
142 * @cb - the callback to the code using the lock module
143 * @sdp - The GFS2 superblock
144 * @min_lvb_size - the mininum LVB size that the caller can deal with
145 * @flags - LM_MFLAG_*
146 * @lockstruct - a structure returned describing the mount
148 * Returns: 0 on success, -EXXX on failure
151 int gfs2_mount_lockproto(char *proto_name, char *table_name, char *host_data,
152 lm_callback_t cb, void *cb_data,
153 unsigned int min_lvb_size, int flags,
154 struct lm_lockstruct *lockstruct,
155 struct kobject *fskobj)
157 struct lmh_wrapper *lw = NULL;
163 mutex_lock(&lmh_lock);
165 if (list_empty(&nolock_proto.lw_list))
166 list_add(&nolock_proto.lw_list, &lmh_list);
169 list_for_each_entry(lw, &lmh_list, lw_list) {
170 if (!strcmp(lw->lw_ops->lm_proto_name, proto_name)) {
177 if (!try && capable(CAP_SYS_MODULE)) {
179 mutex_unlock(&lmh_lock);
180 request_module(proto_name);
183 printk(KERN_INFO "GFS2: can't find protocol %s\n", proto_name);
188 if (lw->lw_ops->lm_owner &&
189 !try_module_get(lw->lw_ops->lm_owner)) {
191 mutex_unlock(&lmh_lock);
196 error = lw->lw_ops->lm_mount(table_name, host_data, cb, cb_data,
197 min_lvb_size, flags, lockstruct, fskobj);
199 module_put(lw->lw_ops->lm_owner);
201 mutex_unlock(&lmh_lock);
205 void gfs2_unmount_lockproto(struct lm_lockstruct *lockstruct)
207 mutex_lock(&lmh_lock);
208 if (lockstruct->ls_ops->lm_unmount)
209 lockstruct->ls_ops->lm_unmount(lockstruct->ls_lockspace);
210 if (lockstruct->ls_ops->lm_owner)
211 module_put(lockstruct->ls_ops->lm_owner);
212 mutex_unlock(&lmh_lock);
216 * gfs2_withdraw_lockproto - abnormally unmount a lock module
217 * @lockstruct: the lockstruct passed into mount
221 void gfs2_withdraw_lockproto(struct lm_lockstruct *lockstruct)
223 mutex_lock(&lmh_lock);
224 lockstruct->ls_ops->lm_withdraw(lockstruct->ls_lockspace);
225 if (lockstruct->ls_ops->lm_owner)
226 module_put(lockstruct->ls_ops->lm_owner);
227 mutex_unlock(&lmh_lock);
230 EXPORT_SYMBOL_GPL(gfs2_register_lockproto);
231 EXPORT_SYMBOL_GPL(gfs2_unregister_lockproto);