diff options
Diffstat (limited to 'fs/gfs2/locking/dlm/plock.c')
-rw-r--r-- | fs/gfs2/locking/dlm/plock.c | 301 |
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 | |||
15 | static spinlock_t ops_lock; | ||
16 | static struct list_head send_list; | ||
17 | static struct list_head recv_list; | ||
18 | static wait_queue_head_t send_wq; | ||
19 | static wait_queue_head_t recv_wq; | ||
20 | |||
21 | struct plock_op { | ||
22 | struct list_head list; | ||
23 | int done; | ||
24 | struct gdlm_plock_info info; | ||
25 | }; | ||
26 | |||
27 | static 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 | |||
34 | static 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 | |||
51 | static 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 | |||
61 | int 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 | |||
105 | int 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 | |||
144 | int 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 */ | ||
189 | static 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 */ | ||
216 | static 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 | |||
253 | static 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 | |||
266 | static struct file_operations dev_fops = { | ||
267 | .read = dev_read, | ||
268 | .write = dev_write, | ||
269 | .poll = dev_poll, | ||
270 | .owner = THIS_MODULE | ||
271 | }; | ||
272 | |||
273 | static struct miscdevice plock_dev_misc = { | ||
274 | .minor = MISC_DYNAMIC_MINOR, | ||
275 | .name = GDLM_PLOCK_MISC_NAME, | ||
276 | .fops = &dev_fops | ||
277 | }; | ||
278 | |||
279 | int 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 | |||
296 | void 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 | |||