Root/
1 | /* |
2 | * Copyright (C) 2005-2008 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/fs.h> |
10 | #include <linux/miscdevice.h> |
11 | #include <linux/poll.h> |
12 | #include <linux/dlm.h> |
13 | #include <linux/dlm_plock.h> |
14 | |
15 | #include "dlm_internal.h" |
16 | #include "lockspace.h" |
17 | |
18 | static spinlock_t ops_lock; |
19 | static struct list_head send_list; |
20 | static struct list_head recv_list; |
21 | static wait_queue_head_t send_wq; |
22 | static wait_queue_head_t recv_wq; |
23 | |
24 | struct plock_op { |
25 | struct list_head list; |
26 | int done; |
27 | struct dlm_plock_info info; |
28 | }; |
29 | |
30 | struct plock_xop { |
31 | struct plock_op xop; |
32 | void *callback; |
33 | void *fl; |
34 | void *file; |
35 | struct file_lock flc; |
36 | }; |
37 | |
38 | |
39 | static inline void set_version(struct dlm_plock_info *info) |
40 | { |
41 | info->version[0] = DLM_PLOCK_VERSION_MAJOR; |
42 | info->version[1] = DLM_PLOCK_VERSION_MINOR; |
43 | info->version[2] = DLM_PLOCK_VERSION_PATCH; |
44 | } |
45 | |
46 | static int check_version(struct dlm_plock_info *info) |
47 | { |
48 | if ((DLM_PLOCK_VERSION_MAJOR != info->version[0]) || |
49 | (DLM_PLOCK_VERSION_MINOR < info->version[1])) { |
50 | log_print("plock device version mismatch: " |
51 | "kernel (%u.%u.%u), user (%u.%u.%u)", |
52 | DLM_PLOCK_VERSION_MAJOR, |
53 | DLM_PLOCK_VERSION_MINOR, |
54 | DLM_PLOCK_VERSION_PATCH, |
55 | info->version[0], |
56 | info->version[1], |
57 | info->version[2]); |
58 | return -EINVAL; |
59 | } |
60 | return 0; |
61 | } |
62 | |
63 | static void send_op(struct plock_op *op) |
64 | { |
65 | set_version(&op->info); |
66 | INIT_LIST_HEAD(&op->list); |
67 | spin_lock(&ops_lock); |
68 | list_add_tail(&op->list, &send_list); |
69 | spin_unlock(&ops_lock); |
70 | wake_up(&send_wq); |
71 | } |
72 | |
73 | int dlm_posix_lock(dlm_lockspace_t *lockspace, u64 number, struct file *file, |
74 | int cmd, struct file_lock *fl) |
75 | { |
76 | struct dlm_ls *ls; |
77 | struct plock_op *op; |
78 | struct plock_xop *xop; |
79 | int rv; |
80 | |
81 | ls = dlm_find_lockspace_local(lockspace); |
82 | if (!ls) |
83 | return -EINVAL; |
84 | |
85 | xop = kzalloc(sizeof(*xop), GFP_KERNEL); |
86 | if (!xop) { |
87 | rv = -ENOMEM; |
88 | goto out; |
89 | } |
90 | |
91 | op = &xop->xop; |
92 | op->info.optype = DLM_PLOCK_OP_LOCK; |
93 | op->info.pid = fl->fl_pid; |
94 | op->info.ex = (fl->fl_type == F_WRLCK); |
95 | op->info.wait = IS_SETLKW(cmd); |
96 | op->info.fsid = ls->ls_global_id; |
97 | op->info.number = number; |
98 | op->info.start = fl->fl_start; |
99 | op->info.end = fl->fl_end; |
100 | if (fl->fl_lmops && fl->fl_lmops->fl_grant) { |
101 | /* fl_owner is lockd which doesn't distinguish |
102 | processes on the nfs client */ |
103 | op->info.owner = (__u64) fl->fl_pid; |
104 | xop->callback = fl->fl_lmops->fl_grant; |
105 | locks_init_lock(&xop->flc); |
106 | locks_copy_lock(&xop->flc, fl); |
107 | xop->fl = fl; |
108 | xop->file = file; |
109 | } else { |
110 | op->info.owner = (__u64)(long) fl->fl_owner; |
111 | xop->callback = NULL; |
112 | } |
113 | |
114 | send_op(op); |
115 | |
116 | if (xop->callback == NULL) |
117 | wait_event(recv_wq, (op->done != 0)); |
118 | else { |
119 | rv = FILE_LOCK_DEFERRED; |
120 | goto out; |
121 | } |
122 | |
123 | spin_lock(&ops_lock); |
124 | if (!list_empty(&op->list)) { |
125 | log_error(ls, "dlm_posix_lock: op on list %llx", |
126 | (unsigned long long)number); |
127 | list_del(&op->list); |
128 | } |
129 | spin_unlock(&ops_lock); |
130 | |
131 | rv = op->info.rv; |
132 | |
133 | if (!rv) { |
134 | if (posix_lock_file_wait(file, fl) < 0) |
135 | log_error(ls, "dlm_posix_lock: vfs lock error %llx", |
136 | (unsigned long long)number); |
137 | } |
138 | |
139 | kfree(xop); |
140 | out: |
141 | dlm_put_lockspace(ls); |
142 | return rv; |
143 | } |
144 | EXPORT_SYMBOL_GPL(dlm_posix_lock); |
145 | |
146 | /* Returns failure iff a succesful lock operation should be canceled */ |
147 | static int dlm_plock_callback(struct plock_op *op) |
148 | { |
149 | struct file *file; |
150 | struct file_lock *fl; |
151 | struct file_lock *flc; |
152 | int (*notify)(void *, void *, int) = NULL; |
153 | struct plock_xop *xop = (struct plock_xop *)op; |
154 | int rv = 0; |
155 | |
156 | spin_lock(&ops_lock); |
157 | if (!list_empty(&op->list)) { |
158 | log_print("dlm_plock_callback: op on list %llx", |
159 | (unsigned long long)op->info.number); |
160 | list_del(&op->list); |
161 | } |
162 | spin_unlock(&ops_lock); |
163 | |
164 | /* check if the following 2 are still valid or make a copy */ |
165 | file = xop->file; |
166 | flc = &xop->flc; |
167 | fl = xop->fl; |
168 | notify = xop->callback; |
169 | |
170 | if (op->info.rv) { |
171 | notify(fl, NULL, op->info.rv); |
172 | goto out; |
173 | } |
174 | |
175 | /* got fs lock; bookkeep locally as well: */ |
176 | flc->fl_flags &= ~FL_SLEEP; |
177 | if (posix_lock_file(file, flc, NULL)) { |
178 | /* |
179 | * This can only happen in the case of kmalloc() failure. |
180 | * The filesystem's own lock is the authoritative lock, |
181 | * so a failure to get the lock locally is not a disaster. |
182 | * As long as the fs cannot reliably cancel locks (especially |
183 | * in a low-memory situation), we're better off ignoring |
184 | * this failure than trying to recover. |
185 | */ |
186 | log_print("dlm_plock_callback: vfs lock error %llx file %p fl %p", |
187 | (unsigned long long)op->info.number, file, fl); |
188 | } |
189 | |
190 | rv = notify(fl, NULL, 0); |
191 | if (rv) { |
192 | /* XXX: We need to cancel the fs lock here: */ |
193 | log_print("dlm_plock_callback: lock granted after lock request " |
194 | "failed; dangling lock!\n"); |
195 | goto out; |
196 | } |
197 | |
198 | out: |
199 | kfree(xop); |
200 | return rv; |
201 | } |
202 | |
203 | int dlm_posix_unlock(dlm_lockspace_t *lockspace, u64 number, struct file *file, |
204 | struct file_lock *fl) |
205 | { |
206 | struct dlm_ls *ls; |
207 | struct plock_op *op; |
208 | int rv; |
209 | |
210 | ls = dlm_find_lockspace_local(lockspace); |
211 | if (!ls) |
212 | return -EINVAL; |
213 | |
214 | op = kzalloc(sizeof(*op), GFP_KERNEL); |
215 | if (!op) { |
216 | rv = -ENOMEM; |
217 | goto out; |
218 | } |
219 | |
220 | if (posix_lock_file_wait(file, fl) < 0) |
221 | log_error(ls, "dlm_posix_unlock: vfs unlock error %llx", |
222 | (unsigned long long)number); |
223 | |
224 | op->info.optype = DLM_PLOCK_OP_UNLOCK; |
225 | op->info.pid = fl->fl_pid; |
226 | op->info.fsid = ls->ls_global_id; |
227 | op->info.number = number; |
228 | op->info.start = fl->fl_start; |
229 | op->info.end = fl->fl_end; |
230 | if (fl->fl_lmops && fl->fl_lmops->fl_grant) |
231 | op->info.owner = (__u64) fl->fl_pid; |
232 | else |
233 | op->info.owner = (__u64)(long) fl->fl_owner; |
234 | |
235 | send_op(op); |
236 | wait_event(recv_wq, (op->done != 0)); |
237 | |
238 | spin_lock(&ops_lock); |
239 | if (!list_empty(&op->list)) { |
240 | log_error(ls, "dlm_posix_unlock: op on list %llx", |
241 | (unsigned long long)number); |
242 | list_del(&op->list); |
243 | } |
244 | spin_unlock(&ops_lock); |
245 | |
246 | rv = op->info.rv; |
247 | |
248 | if (rv == -ENOENT) |
249 | rv = 0; |
250 | |
251 | kfree(op); |
252 | out: |
253 | dlm_put_lockspace(ls); |
254 | return rv; |
255 | } |
256 | EXPORT_SYMBOL_GPL(dlm_posix_unlock); |
257 | |
258 | int dlm_posix_get(dlm_lockspace_t *lockspace, u64 number, struct file *file, |
259 | struct file_lock *fl) |
260 | { |
261 | struct dlm_ls *ls; |
262 | struct plock_op *op; |
263 | int rv; |
264 | |
265 | ls = dlm_find_lockspace_local(lockspace); |
266 | if (!ls) |
267 | return -EINVAL; |
268 | |
269 | op = kzalloc(sizeof(*op), GFP_KERNEL); |
270 | if (!op) { |
271 | rv = -ENOMEM; |
272 | goto out; |
273 | } |
274 | |
275 | op->info.optype = DLM_PLOCK_OP_GET; |
276 | op->info.pid = fl->fl_pid; |
277 | op->info.ex = (fl->fl_type == F_WRLCK); |
278 | op->info.fsid = ls->ls_global_id; |
279 | op->info.number = number; |
280 | op->info.start = fl->fl_start; |
281 | op->info.end = fl->fl_end; |
282 | if (fl->fl_lmops && fl->fl_lmops->fl_grant) |
283 | op->info.owner = (__u64) fl->fl_pid; |
284 | else |
285 | op->info.owner = (__u64)(long) fl->fl_owner; |
286 | |
287 | send_op(op); |
288 | wait_event(recv_wq, (op->done != 0)); |
289 | |
290 | spin_lock(&ops_lock); |
291 | if (!list_empty(&op->list)) { |
292 | log_error(ls, "dlm_posix_get: op on list %llx", |
293 | (unsigned long long)number); |
294 | list_del(&op->list); |
295 | } |
296 | spin_unlock(&ops_lock); |
297 | |
298 | /* info.rv from userspace is 1 for conflict, 0 for no-conflict, |
299 | -ENOENT if there are no locks on the file */ |
300 | |
301 | rv = op->info.rv; |
302 | |
303 | fl->fl_type = F_UNLCK; |
304 | if (rv == -ENOENT) |
305 | rv = 0; |
306 | else if (rv > 0) { |
307 | locks_init_lock(fl); |
308 | fl->fl_type = (op->info.ex) ? F_WRLCK : F_RDLCK; |
309 | fl->fl_flags = FL_POSIX; |
310 | fl->fl_pid = op->info.pid; |
311 | fl->fl_start = op->info.start; |
312 | fl->fl_end = op->info.end; |
313 | rv = 0; |
314 | } |
315 | |
316 | kfree(op); |
317 | out: |
318 | dlm_put_lockspace(ls); |
319 | return rv; |
320 | } |
321 | EXPORT_SYMBOL_GPL(dlm_posix_get); |
322 | |
323 | /* a read copies out one plock request from the send list */ |
324 | static ssize_t dev_read(struct file *file, char __user *u, size_t count, |
325 | loff_t *ppos) |
326 | { |
327 | struct dlm_plock_info info; |
328 | struct plock_op *op = NULL; |
329 | |
330 | if (count < sizeof(info)) |
331 | return -EINVAL; |
332 | |
333 | spin_lock(&ops_lock); |
334 | if (!list_empty(&send_list)) { |
335 | op = list_entry(send_list.next, struct plock_op, list); |
336 | list_move(&op->list, &recv_list); |
337 | memcpy(&info, &op->info, sizeof(info)); |
338 | } |
339 | spin_unlock(&ops_lock); |
340 | |
341 | if (!op) |
342 | return -EAGAIN; |
343 | |
344 | if (copy_to_user(u, &info, sizeof(info))) |
345 | return -EFAULT; |
346 | return sizeof(info); |
347 | } |
348 | |
349 | /* a write copies in one plock result that should match a plock_op |
350 | on the recv list */ |
351 | static ssize_t dev_write(struct file *file, const char __user *u, size_t count, |
352 | loff_t *ppos) |
353 | { |
354 | struct dlm_plock_info info; |
355 | struct plock_op *op; |
356 | int found = 0, do_callback = 0; |
357 | |
358 | if (count != sizeof(info)) |
359 | return -EINVAL; |
360 | |
361 | if (copy_from_user(&info, u, sizeof(info))) |
362 | return -EFAULT; |
363 | |
364 | if (check_version(&info)) |
365 | return -EINVAL; |
366 | |
367 | spin_lock(&ops_lock); |
368 | list_for_each_entry(op, &recv_list, list) { |
369 | if (op->info.fsid == info.fsid && |
370 | op->info.number == info.number && |
371 | op->info.owner == info.owner) { |
372 | struct plock_xop *xop = (struct plock_xop *)op; |
373 | list_del_init(&op->list); |
374 | memcpy(&op->info, &info, sizeof(info)); |
375 | if (xop->callback) |
376 | do_callback = 1; |
377 | else |
378 | op->done = 1; |
379 | found = 1; |
380 | break; |
381 | } |
382 | } |
383 | spin_unlock(&ops_lock); |
384 | |
385 | if (found) { |
386 | if (do_callback) |
387 | dlm_plock_callback(op); |
388 | else |
389 | wake_up(&recv_wq); |
390 | } else |
391 | log_print("dev_write no op %x %llx", info.fsid, |
392 | (unsigned long long)info.number); |
393 | return count; |
394 | } |
395 | |
396 | static unsigned int dev_poll(struct file *file, poll_table *wait) |
397 | { |
398 | unsigned int mask = 0; |
399 | |
400 | poll_wait(file, &send_wq, wait); |
401 | |
402 | spin_lock(&ops_lock); |
403 | if (!list_empty(&send_list)) |
404 | mask = POLLIN | POLLRDNORM; |
405 | spin_unlock(&ops_lock); |
406 | |
407 | return mask; |
408 | } |
409 | |
410 | static const struct file_operations dev_fops = { |
411 | .read = dev_read, |
412 | .write = dev_write, |
413 | .poll = dev_poll, |
414 | .owner = THIS_MODULE |
415 | }; |
416 | |
417 | static struct miscdevice plock_dev_misc = { |
418 | .minor = MISC_DYNAMIC_MINOR, |
419 | .name = DLM_PLOCK_MISC_NAME, |
420 | .fops = &dev_fops |
421 | }; |
422 | |
423 | int dlm_plock_init(void) |
424 | { |
425 | int rv; |
426 | |
427 | spin_lock_init(&ops_lock); |
428 | INIT_LIST_HEAD(&send_list); |
429 | INIT_LIST_HEAD(&recv_list); |
430 | init_waitqueue_head(&send_wq); |
431 | init_waitqueue_head(&recv_wq); |
432 | |
433 | rv = misc_register(&plock_dev_misc); |
434 | if (rv) |
435 | log_print("dlm_plock_init: misc_register failed %d", rv); |
436 | return rv; |
437 | } |
438 | |
439 | void dlm_plock_exit(void) |
440 | { |
441 | if (misc_deregister(&plock_dev_misc) < 0) |
442 | log_print("dlm_plock_exit: misc_deregister failed"); |
443 | } |
444 | |
445 |
Branches:
ben-wpan
ben-wpan-stefan
javiroman/ks7010
jz-2.6.34
jz-2.6.34-rc5
jz-2.6.34-rc6
jz-2.6.34-rc7
jz-2.6.35
jz-2.6.36
jz-2.6.37
jz-2.6.38
jz-2.6.39
jz-3.0
jz-3.1
jz-3.11
jz-3.12
jz-3.13
jz-3.15
jz-3.16
jz-3.18-dt
jz-3.2
jz-3.3
jz-3.4
jz-3.5
jz-3.6
jz-3.6-rc2-pwm
jz-3.9
jz-3.9-clk
jz-3.9-rc8
jz47xx
jz47xx-2.6.38
master
Tags:
od-2011-09-04
od-2011-09-18
v2.6.34-rc5
v2.6.34-rc6
v2.6.34-rc7
v3.9