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-rw-r--r--fs/gfs2/locking/dlm/plock.c301
1 files changed, 301 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..7365aec9511b
--- /dev/null
+++ b/fs/gfs2/locking/dlm/plock.c
@@ -0,0 +1,301 @@
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 version 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(void *lockspace, struct lm_lockname *name,
62 struct file *file, int cmd, struct file_lock *fl)
63{
64 struct gdlm_ls *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 = fl->fl_pid;
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 op->info.owner = (__u64)(long) fl->fl_owner;
81
82 send_op(op);
83 wait_event(recv_wq, (op->done != 0));
84
85 spin_lock(&ops_lock);
86 if (!list_empty(&op->list)) {
87 printk(KERN_INFO "plock op on list\n");
88 list_del(&op->list);
89 }
90 spin_unlock(&ops_lock);
91
92 rv = op->info.rv;
93
94 if (!rv) {
95 if (posix_lock_file_wait(file, fl) < 0)
96 log_error("gdlm_plock: vfs lock error %x,%llx",
97 name->ln_type,
98 (unsigned long long)name->ln_number);
99 }
100
101 kfree(op);
102 return rv;
103}
104
105int gdlm_punlock(void *lockspace, struct lm_lockname *name,
106 struct file *file, struct file_lock *fl)
107{
108 struct gdlm_ls *ls = lockspace;
109 struct plock_op *op;
110 int rv;
111
112 op = kzalloc(sizeof(*op), GFP_KERNEL);
113 if (!op)
114 return -ENOMEM;
115
116 if (posix_lock_file_wait(file, fl) < 0)
117 log_error("gdlm_punlock: vfs unlock error %x,%llx",
118 name->ln_type, (unsigned long long)name->ln_number);
119
120 op->info.optype = GDLM_PLOCK_OP_UNLOCK;
121 op->info.pid = fl->fl_pid;
122 op->info.fsid = ls->id;
123 op->info.number = name->ln_number;
124 op->info.start = fl->fl_start;
125 op->info.end = fl->fl_end;
126 op->info.owner = (__u64)(long) fl->fl_owner;
127
128 send_op(op);
129 wait_event(recv_wq, (op->done != 0));
130
131 spin_lock(&ops_lock);
132 if (!list_empty(&op->list)) {
133 printk(KERN_INFO "punlock op on list\n");
134 list_del(&op->list);
135 }
136 spin_unlock(&ops_lock);
137
138 rv = op->info.rv;
139
140 kfree(op);
141 return rv;
142}
143
144int gdlm_plock_get(void *lockspace, struct lm_lockname *name,
145 struct file *file, struct file_lock *fl)
146{
147 struct gdlm_ls *ls = lockspace;
148 struct plock_op *op;
149 int rv;
150
151 op = kzalloc(sizeof(*op), GFP_KERNEL);
152 if (!op)
153 return -ENOMEM;
154
155 op->info.optype = GDLM_PLOCK_OP_GET;
156 op->info.pid = fl->fl_pid;
157 op->info.ex = (fl->fl_type == F_WRLCK);
158 op->info.fsid = ls->id;
159 op->info.number = name->ln_number;
160 op->info.start = fl->fl_start;
161 op->info.end = fl->fl_end;
162
163 send_op(op);
164 wait_event(recv_wq, (op->done != 0));
165
166 spin_lock(&ops_lock);
167 if (!list_empty(&op->list)) {
168 printk(KERN_INFO "plock_get op on list\n");
169 list_del(&op->list);
170 }
171 spin_unlock(&ops_lock);
172
173 rv = op->info.rv;
174
175 if (rv == 0)
176 fl->fl_type = F_UNLCK;
177 else if (rv > 0) {
178 fl->fl_type = (op->info.ex) ? F_WRLCK : F_RDLCK;
179 fl->fl_pid = op->info.pid;
180 fl->fl_start = op->info.start;
181 fl->fl_end = op->info.end;
182 }
183
184 kfree(op);
185 return rv;
186}
187
188/* a read copies out one plock request from the send list */
189static ssize_t dev_read(struct file *file, char __user *u, size_t count,
190 loff_t *ppos)
191{
192 struct gdlm_plock_info info;
193 struct plock_op *op = NULL;
194
195 if (count < sizeof(info))
196 return -EINVAL;
197
198 spin_lock(&ops_lock);
199 if (!list_empty(&send_list)) {
200 op = list_entry(send_list.next, struct plock_op, list);
201 list_move(&op->list, &recv_list);
202 memcpy(&info, &op->info, sizeof(info));
203 }
204 spin_unlock(&ops_lock);
205
206 if (!op)
207 return -EAGAIN;
208
209 if (copy_to_user(u, &info, sizeof(info)))
210 return -EFAULT;
211 return sizeof(info);
212}
213
214/* a write copies in one plock result that should match a plock_op
215 on the recv list */
216static ssize_t dev_write(struct file *file, const char __user *u, size_t count,
217 loff_t *ppos)
218{
219 struct gdlm_plock_info info;
220 struct plock_op *op;
221 int found = 0;
222
223 if (count != sizeof(info))
224 return -EINVAL;
225
226 if (copy_from_user(&info, u, sizeof(info)))
227 return -EFAULT;
228
229 if (check_version(&info))
230 return -EINVAL;
231
232 spin_lock(&ops_lock);
233 list_for_each_entry(op, &recv_list, list) {
234 if (op->info.fsid == info.fsid && op->info.number == info.number &&
235 op->info.owner == info.owner) {
236 list_del_init(&op->list);
237 found = 1;
238 op->done = 1;
239 memcpy(&op->info, &info, sizeof(info));
240 break;
241 }
242 }
243 spin_unlock(&ops_lock);
244
245 if (found)
246 wake_up(&recv_wq);
247 else
248 printk(KERN_INFO "gdlm dev_write no op %x %llx\n", info.fsid,
249 (unsigned long long)info.number);
250 return count;
251}
252
253static unsigned int dev_poll(struct file *file, poll_table *wait)
254{
255 poll_wait(file, &send_wq, wait);
256
257 spin_lock(&ops_lock);
258 if (!list_empty(&send_list)) {
259 spin_unlock(&ops_lock);
260 return POLLIN | POLLRDNORM;
261 }
262 spin_unlock(&ops_lock);
263 return 0;
264}
265
266static struct file_operations dev_fops = {
267 .read = dev_read,
268 .write = dev_write,
269 .poll = dev_poll,
270 .owner = THIS_MODULE
271};
272
273static struct miscdevice plock_dev_misc = {
274 .minor = MISC_DYNAMIC_MINOR,
275 .name = GDLM_PLOCK_MISC_NAME,
276 .fops = &dev_fops
277};
278
279int gdlm_plock_init(void)
280{
281 int rv;
282
283 spin_lock_init(&ops_lock);
284 INIT_LIST_HEAD(&send_list);
285 INIT_LIST_HEAD(&recv_list);
286 init_waitqueue_head(&send_wq);
287 init_waitqueue_head(&recv_wq);
288
289 rv = misc_register(&plock_dev_misc);
290 if (rv)
291 printk(KERN_INFO "gdlm_plock_init: misc_register failed %d",
292 rv);
293 return rv;
294}
295
296void gdlm_plock_exit(void)
297{
298 if (misc_deregister(&plock_dev_misc) < 0)
299 printk(KERN_INFO "gdlm_plock_exit: misc_deregister failed");
300}
301