aboutsummaryrefslogtreecommitdiffstats
path: root/fs/gfs2/locking/dlm/plock.c
diff options
context:
space:
mode:
Diffstat (limited to 'fs/gfs2/locking/dlm/plock.c')
-rw-r--r--fs/gfs2/locking/dlm/plock.c297
1 files changed, 297 insertions, 0 deletions
diff --git a/fs/gfs2/locking/dlm/plock.c b/fs/gfs2/locking/dlm/plock.c
new file mode 100644
index 000000000000..382847205bc1
--- /dev/null
+++ b/fs/gfs2/locking/dlm/plock.c
@@ -0,0 +1,297 @@
1/*
2 * Copyright (C) 2005 Red Hat, Inc. All rights reserved.
3 *
4 * This copyrighted material is made available to anyone wishing to use,
5 * modify, copy, or redistribute it subject to the terms and conditions
6 * of the GNU General Public License v.2.
7 */
8
9#include <linux/miscdevice.h>
10#include <linux/lock_dlm_plock.h>
11
12#include "lock_dlm.h"
13
14
15static spinlock_t ops_lock;
16static struct list_head send_list;
17static struct list_head recv_list;
18static wait_queue_head_t send_wq;
19static wait_queue_head_t recv_wq;
20
21struct plock_op {
22 struct list_head list;
23 int done;
24 struct gdlm_plock_info info;
25};
26
27static inline void set_version(struct gdlm_plock_info *info)
28{
29 info->version[0] = GDLM_PLOCK_VERSION_MAJOR;
30 info->version[1] = GDLM_PLOCK_VERSION_MINOR;
31 info->version[2] = GDLM_PLOCK_VERSION_PATCH;
32}
33
34static int check_version(struct gdlm_plock_info *info)
35{
36 if ((GDLM_PLOCK_VERSION_MAJOR != info->version[0]) ||
37 (GDLM_PLOCK_VERSION_MINOR < info->version[1])) {
38 log_error("plock device version mismatch: "
39 "kernel (%u.%u.%u), user (%u.%u.%u)",
40 GDLM_PLOCK_VERSION_MAJOR,
41 GDLM_PLOCK_VERSION_MINOR,
42 GDLM_PLOCK_VERSION_PATCH,
43 info->version[0],
44 info->version[1],
45 info->version[2]);
46 return -EINVAL;
47 }
48 return 0;
49}
50
51static void send_op(struct plock_op *op)
52{
53 set_version(&op->info);
54 INIT_LIST_HEAD(&op->list);
55 spin_lock(&ops_lock);
56 list_add_tail(&op->list, &send_list);
57 spin_unlock(&ops_lock);
58 wake_up(&send_wq);
59}
60
61int gdlm_plock(lm_lockspace_t *lockspace, struct lm_lockname *name,
62 struct file *file, int cmd, struct file_lock *fl)
63{
64 struct gdlm_ls *ls = (struct gdlm_ls *) lockspace;
65 struct plock_op *op;
66 int rv;
67
68 op = kzalloc(sizeof(*op), GFP_KERNEL);
69 if (!op)
70 return -ENOMEM;
71
72 op->info.optype = GDLM_PLOCK_OP_LOCK;
73 op->info.pid = (uint32_t) fl->fl_owner;
74 op->info.ex = (fl->fl_type == F_WRLCK);
75 op->info.wait = IS_SETLKW(cmd);
76 op->info.fsid = ls->id;
77 op->info.number = name->ln_number;
78 op->info.start = fl->fl_start;
79 op->info.end = fl->fl_end;
80
81 send_op(op);
82 wait_event(recv_wq, (op->done != 0));
83
84 spin_lock(&ops_lock);
85 if (!list_empty(&op->list)) {
86 printk("plock op on list\n");
87 list_del(&op->list);
88 }
89 spin_unlock(&ops_lock);
90
91 rv = op->info.rv;
92
93 if (!rv) {
94 if (posix_lock_file_wait(file, fl) < 0)
95 log_error("gdlm_plock: vfs lock error %x,%llx",
96 name->ln_type, name->ln_number);
97 }
98
99 kfree(op);
100 return rv;
101}
102
103int gdlm_punlock(lm_lockspace_t *lockspace, struct lm_lockname *name,
104 struct file *file, struct file_lock *fl)
105{
106 struct gdlm_ls *ls = (struct gdlm_ls *) lockspace;
107 struct plock_op *op;
108 int rv;
109
110 op = kzalloc(sizeof(*op), GFP_KERNEL);
111 if (!op)
112 return -ENOMEM;
113
114 if (posix_lock_file_wait(file, fl) < 0)
115 log_error("gdlm_punlock: vfs unlock error %x,%llx",
116 name->ln_type, name->ln_number);
117
118 op->info.optype = GDLM_PLOCK_OP_UNLOCK;
119 op->info.pid = (uint32_t) fl->fl_owner;
120 op->info.fsid = ls->id;
121 op->info.number = name->ln_number;
122 op->info.start = fl->fl_start;
123 op->info.end = fl->fl_end;
124
125 send_op(op);
126 wait_event(recv_wq, (op->done != 0));
127
128 spin_lock(&ops_lock);
129 if (!list_empty(&op->list)) {
130 printk("punlock op on list\n");
131 list_del(&op->list);
132 }
133 spin_unlock(&ops_lock);
134
135 rv = op->info.rv;
136
137 kfree(op);
138 return rv;
139}
140
141int gdlm_plock_get(lm_lockspace_t *lockspace, struct lm_lockname *name,
142 struct file *file, struct file_lock *fl)
143{
144 struct gdlm_ls *ls = (struct gdlm_ls *) lockspace;
145 struct plock_op *op;
146 int rv;
147
148 op = kzalloc(sizeof(*op), GFP_KERNEL);
149 if (!op)
150 return -ENOMEM;
151
152 op->info.optype = GDLM_PLOCK_OP_GET;
153 op->info.pid = (uint32_t) fl->fl_owner;
154 op->info.ex = (fl->fl_type == F_WRLCK);
155 op->info.fsid = ls->id;
156 op->info.number = name->ln_number;
157 op->info.start = fl->fl_start;
158 op->info.end = fl->fl_end;
159
160 send_op(op);
161 wait_event(recv_wq, (op->done != 0));
162
163 spin_lock(&ops_lock);
164 if (!list_empty(&op->list)) {
165 printk("plock_get op on list\n");
166 list_del(&op->list);
167 }
168 spin_unlock(&ops_lock);
169
170 rv = op->info.rv;
171
172 if (rv == 0)
173 fl->fl_type = F_UNLCK;
174 else if (rv > 0) {
175 fl->fl_type = (op->info.ex) ? F_WRLCK : F_RDLCK;
176 fl->fl_pid = op->info.pid;
177 fl->fl_start = op->info.start;
178 fl->fl_end = op->info.end;
179 }
180
181 kfree(op);
182 return rv;
183}
184
185/* a read copies out one plock request from the send list */
186static ssize_t dev_read(struct file *file, char __user *u, size_t count,
187 loff_t *ppos)
188{
189 struct gdlm_plock_info info;
190 struct plock_op *op = NULL;
191
192 if (count < sizeof(info))
193 return -EINVAL;
194
195 spin_lock(&ops_lock);
196 if (!list_empty(&send_list)) {
197 op = list_entry(send_list.next, struct plock_op, list);
198 list_move(&op->list, &recv_list);
199 memcpy(&info, &op->info, sizeof(info));
200 }
201 spin_unlock(&ops_lock);
202
203 if (!op)
204 return -EAGAIN;
205
206 if (copy_to_user(u, &info, sizeof(info)))
207 return -EFAULT;
208 return sizeof(info);
209}
210
211/* a write copies in one plock result that should match a plock_op
212 on the recv list */
213static ssize_t dev_write(struct file *file, const char __user *u, size_t count,
214 loff_t *ppos)
215{
216 struct gdlm_plock_info info;
217 struct plock_op *op;
218 int found = 0;
219
220 if (count != sizeof(info))
221 return -EINVAL;
222
223 if (copy_from_user(&info, u, sizeof(info)))
224 return -EFAULT;
225
226 if (check_version(&info))
227 return -EINVAL;
228
229 spin_lock(&ops_lock);
230 list_for_each_entry(op, &recv_list, list) {
231 if (op->info.fsid == info.fsid &&
232 op->info.number == info.number) {
233 list_del_init(&op->list);
234 found = 1;
235 op->done = 1;
236 memcpy(&op->info, &info, sizeof(info));
237 break;
238 }
239 }
240 spin_unlock(&ops_lock);
241
242 if (found)
243 wake_up(&recv_wq);
244 else
245 printk("gdlm dev_write no op %x %llx\n", info.fsid,
246 info.number);
247 return count;
248}
249
250static unsigned int dev_poll(struct file *file, poll_table *wait)
251{
252 poll_wait(file, &send_wq, wait);
253
254 spin_lock(&ops_lock);
255 if (!list_empty(&send_list)) {
256 spin_unlock(&ops_lock);
257 return POLLIN | POLLRDNORM;
258 }
259 spin_unlock(&ops_lock);
260 return 0;
261}
262
263static struct file_operations dev_fops = {
264 .read = dev_read,
265 .write = dev_write,
266 .poll = dev_poll,
267 .owner = THIS_MODULE
268};
269
270static struct miscdevice plock_dev_misc = {
271 .minor = MISC_DYNAMIC_MINOR,
272 .name = GDLM_PLOCK_MISC_NAME,
273 .fops = &dev_fops
274};
275
276int gdlm_plock_init(void)
277{
278 int rv;
279
280 spin_lock_init(&ops_lock);
281 INIT_LIST_HEAD(&send_list);
282 INIT_LIST_HEAD(&recv_list);
283 init_waitqueue_head(&send_wq);
284 init_waitqueue_head(&recv_wq);
285
286 rv = misc_register(&plock_dev_misc);
287 if (rv)
288 printk("gdlm_plock_init: misc_register failed %d", rv);
289 return rv;
290}
291
292void gdlm_plock_exit(void)
293{
294 if (misc_deregister(&plock_dev_misc) < 0)
295 printk("gdlm_plock_exit: misc_deregister failed");
296}
297
generated by cgit v1.2.2 (git 2.25.0) at 2024-11-19 02:23:41 -0500