d3b8ce6fbbe34aafd0f0045ad1091bd0704f9c44
[linux-3.10.git] / fs / gfs2 / locking / nolock / main.c
1 /*
2  * Copyright (C) Sistina Software, Inc.  1997-2003 All rights reserved.
3  * Copyright (C) 2004-2005 Red Hat, Inc.  All rights reserved.
4  *
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.
8  */
9
10 #include <linux/module.h>
11 #include <linux/slab.h>
12 #include <linux/init.h>
13 #include <linux/types.h>
14 #include <linux/fs.h>
15 #include <linux/lm_interface.h>
16
17 struct nolock_lockspace {
18         unsigned int nl_lvb_size;
19 };
20
21 static const struct lm_lockops nolock_ops;
22
23 static int nolock_mount(char *table_name, char *host_data,
24                         lm_callback_t cb, void *cb_data,
25                         unsigned int min_lvb_size, int flags,
26                         struct lm_lockstruct *lockstruct,
27                         struct kobject *fskobj)
28 {
29         char *c;
30         unsigned int jid;
31         struct nolock_lockspace *nl;
32
33         c = strstr(host_data, "jid=");
34         if (!c)
35                 jid = 0;
36         else {
37                 c += 4;
38                 sscanf(c, "%u", &jid);
39         }
40
41         nl = kzalloc(sizeof(struct nolock_lockspace), GFP_KERNEL);
42         if (!nl)
43                 return -ENOMEM;
44
45         nl->nl_lvb_size = min_lvb_size;
46
47         lockstruct->ls_jid = jid;
48         lockstruct->ls_first = 1;
49         lockstruct->ls_lvb_size = min_lvb_size;
50         lockstruct->ls_lockspace = nl;
51         lockstruct->ls_ops = &nolock_ops;
52         lockstruct->ls_flags = LM_LSFLAG_LOCAL;
53
54         return 0;
55 }
56
57 static void nolock_others_may_mount(void *lockspace)
58 {
59 }
60
61 static void nolock_unmount(void *lockspace)
62 {
63         struct nolock_lockspace *nl = lockspace;
64         kfree(nl);
65 }
66
67 static void nolock_withdraw(void *lockspace)
68 {
69 }
70
71 /**
72  * nolock_get_lock - get a lm_lock_t given a descripton of the lock
73  * @lockspace: the lockspace the lock lives in
74  * @name: the name of the lock
75  * @lockp: return the lm_lock_t here
76  *
77  * Returns: 0 on success, -EXXX on failure
78  */
79
80 static int nolock_get_lock(void *lockspace, struct lm_lockname *name,
81                            void **lockp)
82 {
83         *lockp = lockspace;
84         return 0;
85 }
86
87 /**
88  * nolock_put_lock - get rid of a lock structure
89  * @lock: the lock to throw away
90  *
91  */
92
93 static void nolock_put_lock(void *lock)
94 {
95 }
96
97 /**
98  * nolock_lock - acquire a lock
99  * @lock: the lock to manipulate
100  * @cur_state: the current state
101  * @req_state: the requested state
102  * @flags: modifier flags
103  *
104  * Returns: A bitmap of LM_OUT_*
105  */
106
107 static unsigned int nolock_lock(void *lock, unsigned int cur_state,
108                                 unsigned int req_state, unsigned int flags)
109 {
110         return req_state | LM_OUT_CACHEABLE;
111 }
112
113 /**
114  * nolock_unlock - unlock a lock
115  * @lock: the lock to manipulate
116  * @cur_state: the current state
117  *
118  * Returns: 0
119  */
120
121 static unsigned int nolock_unlock(void *lock, unsigned int cur_state)
122 {
123         return 0;
124 }
125
126 static void nolock_cancel(void *lock)
127 {
128 }
129
130 /**
131  * nolock_hold_lvb - hold on to a lock value block
132  * @lock: the lock the LVB is associated with
133  * @lvbp: return the lm_lvb_t here
134  *
135  * Returns: 0 on success, -EXXX on failure
136  */
137
138 static int nolock_hold_lvb(void *lock, char **lvbp)
139 {
140         struct nolock_lockspace *nl = lock;
141         int error = 0;
142
143         *lvbp = kzalloc(nl->nl_lvb_size, GFP_KERNEL);
144         if (!*lvbp)
145                 error = -ENOMEM;
146
147         return error;
148 }
149
150 /**
151  * nolock_unhold_lvb - release a LVB
152  * @lock: the lock the LVB is associated with
153  * @lvb: the lock value block
154  *
155  */
156
157 static void nolock_unhold_lvb(void *lock, char *lvb)
158 {
159         kfree(lvb);
160 }
161
162 static int nolock_plock_get(void *lockspace, struct lm_lockname *name,
163                             struct file *file, struct file_lock *fl)
164 {
165         posix_test_lock(file, fl);
166
167         return 0;
168 }
169
170 static int nolock_plock(void *lockspace, struct lm_lockname *name,
171                         struct file *file, int cmd, struct file_lock *fl)
172 {
173         int error;
174         error = posix_lock_file_wait(file, fl);
175         return error;
176 }
177
178 static int nolock_punlock(void *lockspace, struct lm_lockname *name,
179                           struct file *file, struct file_lock *fl)
180 {
181         int error;
182         error = posix_lock_file_wait(file, fl);
183         return error;
184 }
185
186 static void nolock_recovery_done(void *lockspace, unsigned int jid,
187                                  unsigned int message)
188 {
189 }
190
191 static const struct lm_lockops nolock_ops = {
192         .lm_proto_name = "lock_nolock",
193         .lm_mount = nolock_mount,
194         .lm_others_may_mount = nolock_others_may_mount,
195         .lm_unmount = nolock_unmount,
196         .lm_withdraw = nolock_withdraw,
197         .lm_get_lock = nolock_get_lock,
198         .lm_put_lock = nolock_put_lock,
199         .lm_lock = nolock_lock,
200         .lm_unlock = nolock_unlock,
201         .lm_cancel = nolock_cancel,
202         .lm_hold_lvb = nolock_hold_lvb,
203         .lm_unhold_lvb = nolock_unhold_lvb,
204         .lm_plock_get = nolock_plock_get,
205         .lm_plock = nolock_plock,
206         .lm_punlock = nolock_punlock,
207         .lm_recovery_done = nolock_recovery_done,
208         .lm_owner = THIS_MODULE,
209 };
210
211 static int __init init_nolock(void)
212 {
213         int error;
214
215         error = gfs2_register_lockproto(&nolock_ops);
216         if (error) {
217                 printk(KERN_WARNING
218                        "lock_nolock: can't register protocol: %d\n", error);
219                 return error;
220         }
221
222         printk(KERN_INFO
223                "Lock_Nolock (built %s %s) installed\n", __DATE__, __TIME__);
224         return 0;
225 }
226
227 static void __exit exit_nolock(void)
228 {
229         gfs2_unregister_lockproto(&nolock_ops);
230 }
231
232 module_init(init_nolock);
233 module_exit(exit_nolock);
234
235 MODULE_DESCRIPTION("GFS Nolock Locking Module");
236 MODULE_AUTHOR("Red Hat, Inc.");
237 MODULE_LICENSE("GPL");
238