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Commit | Line | Data |
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869d81df | 1 | /* |
2402211a | 2 | * Copyright (C) 2005-2008 Red Hat, Inc. All rights reserved. |
869d81df DT |
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 | |
e9fc2aa0 | 6 | * of the GNU General Public License version 2. |
869d81df DT |
7 | */ |
8 | ||
2402211a | 9 | #include <linux/fs.h> |
869d81df | 10 | #include <linux/miscdevice.h> |
bd01f843 | 11 | #include <linux/poll.h> |
2402211a DT |
12 | #include <linux/dlm.h> |
13 | #include <linux/dlm_plock.h> | |
5a0e3ad6 | 14 | #include <linux/slab.h> |
869d81df | 15 | |
2402211a DT |
16 | #include "dlm_internal.h" |
17 | #include "lockspace.h" | |
869d81df DT |
18 | |
19 | static spinlock_t ops_lock; | |
20 | static struct list_head send_list; | |
21 | static struct list_head recv_list; | |
22 | static wait_queue_head_t send_wq; | |
23 | static wait_queue_head_t recv_wq; | |
24 | ||
25 | struct plock_op { | |
26 | struct list_head list; | |
27 | int done; | |
2402211a | 28 | struct dlm_plock_info info; |
869d81df DT |
29 | }; |
30 | ||
586759f0 ME |
31 | struct plock_xop { |
32 | struct plock_op xop; | |
d0449b90 | 33 | int (*callback)(struct file_lock *fl, int result); |
586759f0 ME |
34 | void *fl; |
35 | void *file; | |
36 | struct file_lock flc; | |
37 | }; | |
38 | ||
39 | ||
2402211a | 40 | static inline void set_version(struct dlm_plock_info *info) |
869d81df | 41 | { |
2402211a DT |
42 | info->version[0] = DLM_PLOCK_VERSION_MAJOR; |
43 | info->version[1] = DLM_PLOCK_VERSION_MINOR; | |
44 | info->version[2] = DLM_PLOCK_VERSION_PATCH; | |
869d81df DT |
45 | } |
46 | ||
2402211a | 47 | static int check_version(struct dlm_plock_info *info) |
869d81df | 48 | { |
2402211a DT |
49 | if ((DLM_PLOCK_VERSION_MAJOR != info->version[0]) || |
50 | (DLM_PLOCK_VERSION_MINOR < info->version[1])) { | |
51 | log_print("plock device version mismatch: " | |
869d81df | 52 | "kernel (%u.%u.%u), user (%u.%u.%u)", |
2402211a DT |
53 | DLM_PLOCK_VERSION_MAJOR, |
54 | DLM_PLOCK_VERSION_MINOR, | |
55 | DLM_PLOCK_VERSION_PATCH, | |
869d81df DT |
56 | info->version[0], |
57 | info->version[1], | |
58 | info->version[2]); | |
59 | return -EINVAL; | |
60 | } | |
61 | return 0; | |
62 | } | |
63 | ||
64 | static void send_op(struct plock_op *op) | |
65 | { | |
66 | set_version(&op->info); | |
67 | INIT_LIST_HEAD(&op->list); | |
68 | spin_lock(&ops_lock); | |
69 | list_add_tail(&op->list, &send_list); | |
70 | spin_unlock(&ops_lock); | |
71 | wake_up(&send_wq); | |
72 | } | |
73 | ||
901025d2 DT |
74 | /* If a process was killed while waiting for the only plock on a file, |
75 | locks_remove_posix will not see any lock on the file so it won't | |
76 | send an unlock-close to us to pass on to userspace to clean up the | |
77 | abandoned waiter. So, we have to insert the unlock-close when the | |
78 | lock call is interrupted. */ | |
79 | ||
80 | static void do_unlock_close(struct dlm_ls *ls, u64 number, | |
81 | struct file *file, struct file_lock *fl) | |
82 | { | |
83 | struct plock_op *op; | |
84 | ||
85 | op = kzalloc(sizeof(*op), GFP_NOFS); | |
86 | if (!op) | |
87 | return; | |
88 | ||
89 | op->info.optype = DLM_PLOCK_OP_UNLOCK; | |
90 | op->info.pid = fl->fl_pid; | |
91 | op->info.fsid = ls->ls_global_id; | |
92 | op->info.number = number; | |
93 | op->info.start = 0; | |
94 | op->info.end = OFFSET_MAX; | |
8fb47a4f | 95 | if (fl->fl_lmops && fl->fl_lmops->lm_grant) |
901025d2 DT |
96 | op->info.owner = (__u64) fl->fl_pid; |
97 | else | |
98 | op->info.owner = (__u64)(long) fl->fl_owner; | |
99 | ||
100 | op->info.flags |= DLM_PLOCK_FL_CLOSE; | |
101 | send_op(op); | |
102 | } | |
103 | ||
2402211a DT |
104 | int dlm_posix_lock(dlm_lockspace_t *lockspace, u64 number, struct file *file, |
105 | int cmd, struct file_lock *fl) | |
869d81df | 106 | { |
2402211a | 107 | struct dlm_ls *ls; |
869d81df | 108 | struct plock_op *op; |
586759f0 | 109 | struct plock_xop *xop; |
869d81df DT |
110 | int rv; |
111 | ||
2402211a DT |
112 | ls = dlm_find_lockspace_local(lockspace); |
113 | if (!ls) | |
114 | return -EINVAL; | |
115 | ||
573c24c4 | 116 | xop = kzalloc(sizeof(*xop), GFP_NOFS); |
2402211a DT |
117 | if (!xop) { |
118 | rv = -ENOMEM; | |
119 | goto out; | |
120 | } | |
869d81df | 121 | |
586759f0 | 122 | op = &xop->xop; |
2402211a | 123 | op->info.optype = DLM_PLOCK_OP_LOCK; |
3a2a9c96 | 124 | op->info.pid = fl->fl_pid; |
869d81df DT |
125 | op->info.ex = (fl->fl_type == F_WRLCK); |
126 | op->info.wait = IS_SETLKW(cmd); | |
2402211a DT |
127 | op->info.fsid = ls->ls_global_id; |
128 | op->info.number = number; | |
869d81df DT |
129 | op->info.start = fl->fl_start; |
130 | op->info.end = fl->fl_end; | |
8fb47a4f | 131 | if (fl->fl_lmops && fl->fl_lmops->lm_grant) { |
2066b58b DT |
132 | /* fl_owner is lockd which doesn't distinguish |
133 | processes on the nfs client */ | |
134 | op->info.owner = (__u64) fl->fl_pid; | |
8fb47a4f | 135 | xop->callback = fl->fl_lmops->lm_grant; |
586759f0 ME |
136 | locks_init_lock(&xop->flc); |
137 | locks_copy_lock(&xop->flc, fl); | |
138 | xop->fl = fl; | |
139 | xop->file = file; | |
2066b58b DT |
140 | } else { |
141 | op->info.owner = (__u64)(long) fl->fl_owner; | |
586759f0 | 142 | xop->callback = NULL; |
2066b58b | 143 | } |
869d81df DT |
144 | |
145 | send_op(op); | |
586759f0 | 146 | |
901025d2 | 147 | if (xop->callback == NULL) { |
a6b1533e | 148 | rv = wait_event_interruptible(recv_wq, (op->done != 0)); |
901025d2 DT |
149 | if (rv == -ERESTARTSYS) { |
150 | log_debug(ls, "dlm_posix_lock: wait killed %llx", | |
151 | (unsigned long long)number); | |
152 | spin_lock(&ops_lock); | |
153 | list_del(&op->list); | |
154 | spin_unlock(&ops_lock); | |
155 | kfree(xop); | |
156 | do_unlock_close(ls, number, file, fl); | |
157 | goto out; | |
158 | } | |
159 | } else { | |
bde74e4b | 160 | rv = FILE_LOCK_DEFERRED; |
2402211a DT |
161 | goto out; |
162 | } | |
869d81df DT |
163 | |
164 | spin_lock(&ops_lock); | |
165 | if (!list_empty(&op->list)) { | |
2402211a DT |
166 | log_error(ls, "dlm_posix_lock: op on list %llx", |
167 | (unsigned long long)number); | |
869d81df DT |
168 | list_del(&op->list); |
169 | } | |
170 | spin_unlock(&ops_lock); | |
171 | ||
172 | rv = op->info.rv; | |
173 | ||
174 | if (!rv) { | |
4f656367 | 175 | if (locks_lock_file_wait(file, fl) < 0) |
2402211a DT |
176 | log_error(ls, "dlm_posix_lock: vfs lock error %llx", |
177 | (unsigned long long)number); | |
869d81df DT |
178 | } |
179 | ||
586759f0 | 180 | kfree(xop); |
2402211a DT |
181 | out: |
182 | dlm_put_lockspace(ls); | |
586759f0 ME |
183 | return rv; |
184 | } | |
2402211a | 185 | EXPORT_SYMBOL_GPL(dlm_posix_lock); |
586759f0 | 186 | |
af901ca1 | 187 | /* Returns failure iff a successful lock operation should be canceled */ |
2402211a | 188 | static int dlm_plock_callback(struct plock_op *op) |
586759f0 ME |
189 | { |
190 | struct file *file; | |
191 | struct file_lock *fl; | |
192 | struct file_lock *flc; | |
d0449b90 | 193 | int (*notify)(struct file_lock *fl, int result) = NULL; |
586759f0 ME |
194 | struct plock_xop *xop = (struct plock_xop *)op; |
195 | int rv = 0; | |
196 | ||
197 | spin_lock(&ops_lock); | |
198 | if (!list_empty(&op->list)) { | |
2402211a DT |
199 | log_print("dlm_plock_callback: op on list %llx", |
200 | (unsigned long long)op->info.number); | |
586759f0 ME |
201 | list_del(&op->list); |
202 | } | |
203 | spin_unlock(&ops_lock); | |
204 | ||
205 | /* check if the following 2 are still valid or make a copy */ | |
206 | file = xop->file; | |
207 | flc = &xop->flc; | |
208 | fl = xop->fl; | |
209 | notify = xop->callback; | |
210 | ||
211 | if (op->info.rv) { | |
d0449b90 | 212 | notify(fl, op->info.rv); |
586759f0 ME |
213 | goto out; |
214 | } | |
215 | ||
216 | /* got fs lock; bookkeep locally as well: */ | |
217 | flc->fl_flags &= ~FL_SLEEP; | |
218 | if (posix_lock_file(file, flc, NULL)) { | |
219 | /* | |
220 | * This can only happen in the case of kmalloc() failure. | |
221 | * The filesystem's own lock is the authoritative lock, | |
222 | * so a failure to get the lock locally is not a disaster. | |
2402211a | 223 | * As long as the fs cannot reliably cancel locks (especially |
586759f0 ME |
224 | * in a low-memory situation), we're better off ignoring |
225 | * this failure than trying to recover. | |
226 | */ | |
2402211a DT |
227 | log_print("dlm_plock_callback: vfs lock error %llx file %p fl %p", |
228 | (unsigned long long)op->info.number, file, fl); | |
586759f0 ME |
229 | } |
230 | ||
d0449b90 | 231 | rv = notify(fl, 0); |
586759f0 ME |
232 | if (rv) { |
233 | /* XXX: We need to cancel the fs lock here: */ | |
2402211a DT |
234 | log_print("dlm_plock_callback: lock granted after lock request " |
235 | "failed; dangling lock!\n"); | |
586759f0 ME |
236 | goto out; |
237 | } | |
238 | ||
239 | out: | |
240 | kfree(xop); | |
869d81df DT |
241 | return rv; |
242 | } | |
243 | ||
2402211a DT |
244 | int dlm_posix_unlock(dlm_lockspace_t *lockspace, u64 number, struct file *file, |
245 | struct file_lock *fl) | |
869d81df | 246 | { |
2402211a | 247 | struct dlm_ls *ls; |
869d81df DT |
248 | struct plock_op *op; |
249 | int rv; | |
90008318 | 250 | unsigned char fl_flags = fl->fl_flags; |
869d81df | 251 | |
2402211a DT |
252 | ls = dlm_find_lockspace_local(lockspace); |
253 | if (!ls) | |
254 | return -EINVAL; | |
255 | ||
573c24c4 | 256 | op = kzalloc(sizeof(*op), GFP_NOFS); |
2402211a DT |
257 | if (!op) { |
258 | rv = -ENOMEM; | |
259 | goto out; | |
260 | } | |
869d81df | 261 | |
90008318 DT |
262 | /* cause the vfs unlock to return ENOENT if lock is not found */ |
263 | fl->fl_flags |= FL_EXISTS; | |
264 | ||
4f656367 | 265 | rv = locks_lock_file_wait(file, fl); |
90008318 DT |
266 | if (rv == -ENOENT) { |
267 | rv = 0; | |
268 | goto out_free; | |
269 | } | |
270 | if (rv < 0) { | |
271 | log_error(ls, "dlm_posix_unlock: vfs unlock error %d %llx", | |
272 | rv, (unsigned long long)number); | |
273 | } | |
869d81df | 274 | |
2402211a | 275 | op->info.optype = DLM_PLOCK_OP_UNLOCK; |
3a2a9c96 | 276 | op->info.pid = fl->fl_pid; |
2402211a DT |
277 | op->info.fsid = ls->ls_global_id; |
278 | op->info.number = number; | |
869d81df DT |
279 | op->info.start = fl->fl_start; |
280 | op->info.end = fl->fl_end; | |
8fb47a4f | 281 | if (fl->fl_lmops && fl->fl_lmops->lm_grant) |
2066b58b DT |
282 | op->info.owner = (__u64) fl->fl_pid; |
283 | else | |
284 | op->info.owner = (__u64)(long) fl->fl_owner; | |
869d81df | 285 | |
901025d2 DT |
286 | if (fl->fl_flags & FL_CLOSE) { |
287 | op->info.flags |= DLM_PLOCK_FL_CLOSE; | |
288 | send_op(op); | |
289 | rv = 0; | |
290 | goto out; | |
291 | } | |
292 | ||
869d81df DT |
293 | send_op(op); |
294 | wait_event(recv_wq, (op->done != 0)); | |
295 | ||
296 | spin_lock(&ops_lock); | |
297 | if (!list_empty(&op->list)) { | |
2402211a DT |
298 | log_error(ls, "dlm_posix_unlock: op on list %llx", |
299 | (unsigned long long)number); | |
869d81df DT |
300 | list_del(&op->list); |
301 | } | |
302 | spin_unlock(&ops_lock); | |
303 | ||
304 | rv = op->info.rv; | |
305 | ||
586759f0 ME |
306 | if (rv == -ENOENT) |
307 | rv = 0; | |
308 | ||
90008318 | 309 | out_free: |
869d81df | 310 | kfree(op); |
2402211a DT |
311 | out: |
312 | dlm_put_lockspace(ls); | |
90008318 | 313 | fl->fl_flags = fl_flags; |
869d81df DT |
314 | return rv; |
315 | } | |
2402211a | 316 | EXPORT_SYMBOL_GPL(dlm_posix_unlock); |
869d81df | 317 | |
2402211a DT |
318 | int dlm_posix_get(dlm_lockspace_t *lockspace, u64 number, struct file *file, |
319 | struct file_lock *fl) | |
869d81df | 320 | { |
2402211a | 321 | struct dlm_ls *ls; |
869d81df DT |
322 | struct plock_op *op; |
323 | int rv; | |
324 | ||
2402211a DT |
325 | ls = dlm_find_lockspace_local(lockspace); |
326 | if (!ls) | |
327 | return -EINVAL; | |
328 | ||
573c24c4 | 329 | op = kzalloc(sizeof(*op), GFP_NOFS); |
2402211a DT |
330 | if (!op) { |
331 | rv = -ENOMEM; | |
332 | goto out; | |
333 | } | |
869d81df | 334 | |
2402211a | 335 | op->info.optype = DLM_PLOCK_OP_GET; |
3a2a9c96 | 336 | op->info.pid = fl->fl_pid; |
869d81df | 337 | op->info.ex = (fl->fl_type == F_WRLCK); |
2402211a DT |
338 | op->info.fsid = ls->ls_global_id; |
339 | op->info.number = number; | |
869d81df DT |
340 | op->info.start = fl->fl_start; |
341 | op->info.end = fl->fl_end; | |
8fb47a4f | 342 | if (fl->fl_lmops && fl->fl_lmops->lm_grant) |
2066b58b DT |
343 | op->info.owner = (__u64) fl->fl_pid; |
344 | else | |
345 | op->info.owner = (__u64)(long) fl->fl_owner; | |
586759f0 | 346 | |
869d81df DT |
347 | send_op(op); |
348 | wait_event(recv_wq, (op->done != 0)); | |
349 | ||
350 | spin_lock(&ops_lock); | |
351 | if (!list_empty(&op->list)) { | |
2402211a DT |
352 | log_error(ls, "dlm_posix_get: op on list %llx", |
353 | (unsigned long long)number); | |
869d81df DT |
354 | list_del(&op->list); |
355 | } | |
356 | spin_unlock(&ops_lock); | |
357 | ||
a7a2ff8a DT |
358 | /* info.rv from userspace is 1 for conflict, 0 for no-conflict, |
359 | -ENOENT if there are no locks on the file */ | |
360 | ||
869d81df DT |
361 | rv = op->info.rv; |
362 | ||
586759f0 ME |
363 | fl->fl_type = F_UNLCK; |
364 | if (rv == -ENOENT) | |
365 | rv = 0; | |
a7a2ff8a | 366 | else if (rv > 0) { |
20d5a399 | 367 | locks_init_lock(fl); |
869d81df | 368 | fl->fl_type = (op->info.ex) ? F_WRLCK : F_RDLCK; |
20d5a399 | 369 | fl->fl_flags = FL_POSIX; |
9d5b86ac | 370 | fl->fl_pid = -op->info.pid; |
869d81df DT |
371 | fl->fl_start = op->info.start; |
372 | fl->fl_end = op->info.end; | |
a7a2ff8a | 373 | rv = 0; |
869d81df DT |
374 | } |
375 | ||
376 | kfree(op); | |
2402211a DT |
377 | out: |
378 | dlm_put_lockspace(ls); | |
869d81df DT |
379 | return rv; |
380 | } | |
2402211a | 381 | EXPORT_SYMBOL_GPL(dlm_posix_get); |
869d81df DT |
382 | |
383 | /* a read copies out one plock request from the send list */ | |
384 | static ssize_t dev_read(struct file *file, char __user *u, size_t count, | |
385 | loff_t *ppos) | |
386 | { | |
2402211a | 387 | struct dlm_plock_info info; |
869d81df DT |
388 | struct plock_op *op = NULL; |
389 | ||
390 | if (count < sizeof(info)) | |
391 | return -EINVAL; | |
392 | ||
393 | spin_lock(&ops_lock); | |
394 | if (!list_empty(&send_list)) { | |
395 | op = list_entry(send_list.next, struct plock_op, list); | |
901025d2 DT |
396 | if (op->info.flags & DLM_PLOCK_FL_CLOSE) |
397 | list_del(&op->list); | |
398 | else | |
399 | list_move(&op->list, &recv_list); | |
869d81df DT |
400 | memcpy(&info, &op->info, sizeof(info)); |
401 | } | |
402 | spin_unlock(&ops_lock); | |
403 | ||
404 | if (!op) | |
405 | return -EAGAIN; | |
406 | ||
901025d2 DT |
407 | /* there is no need to get a reply from userspace for unlocks |
408 | that were generated by the vfs cleaning up for a close | |
409 | (the process did not make an unlock call). */ | |
410 | ||
411 | if (op->info.flags & DLM_PLOCK_FL_CLOSE) | |
412 | kfree(op); | |
413 | ||
869d81df DT |
414 | if (copy_to_user(u, &info, sizeof(info))) |
415 | return -EFAULT; | |
416 | return sizeof(info); | |
417 | } | |
418 | ||
419 | /* a write copies in one plock result that should match a plock_op | |
420 | on the recv list */ | |
421 | static ssize_t dev_write(struct file *file, const char __user *u, size_t count, | |
422 | loff_t *ppos) | |
423 | { | |
2402211a | 424 | struct dlm_plock_info info; |
869d81df | 425 | struct plock_op *op; |
c78a87d0 | 426 | int found = 0, do_callback = 0; |
869d81df DT |
427 | |
428 | if (count != sizeof(info)) | |
429 | return -EINVAL; | |
430 | ||
431 | if (copy_from_user(&info, u, sizeof(info))) | |
432 | return -EFAULT; | |
433 | ||
434 | if (check_version(&info)) | |
435 | return -EINVAL; | |
436 | ||
437 | spin_lock(&ops_lock); | |
438 | list_for_each_entry(op, &recv_list, list) { | |
c78a87d0 DT |
439 | if (op->info.fsid == info.fsid && |
440 | op->info.number == info.number && | |
08eac93a | 441 | op->info.owner == info.owner) { |
c78a87d0 | 442 | struct plock_xop *xop = (struct plock_xop *)op; |
869d81df | 443 | list_del_init(&op->list); |
869d81df | 444 | memcpy(&op->info, &info, sizeof(info)); |
c78a87d0 DT |
445 | if (xop->callback) |
446 | do_callback = 1; | |
447 | else | |
448 | op->done = 1; | |
449 | found = 1; | |
869d81df DT |
450 | break; |
451 | } | |
452 | } | |
453 | spin_unlock(&ops_lock); | |
454 | ||
586759f0 | 455 | if (found) { |
c78a87d0 | 456 | if (do_callback) |
817d10ba | 457 | dlm_plock_callback(op); |
586759f0 ME |
458 | else |
459 | wake_up(&recv_wq); | |
460 | } else | |
2402211a DT |
461 | log_print("dev_write no op %x %llx", info.fsid, |
462 | (unsigned long long)info.number); | |
869d81df DT |
463 | return count; |
464 | } | |
465 | ||
076ccb76 | 466 | static __poll_t dev_poll(struct file *file, poll_table *wait) |
869d81df | 467 | { |
076ccb76 | 468 | __poll_t mask = 0; |
cee23c79 | 469 | |
869d81df DT |
470 | poll_wait(file, &send_wq, wait); |
471 | ||
472 | spin_lock(&ops_lock); | |
cee23c79 | 473 | if (!list_empty(&send_list)) |
a9a08845 | 474 | mask = EPOLLIN | EPOLLRDNORM; |
869d81df | 475 | spin_unlock(&ops_lock); |
cee23c79 DC |
476 | |
477 | return mask; | |
869d81df DT |
478 | } |
479 | ||
00977a59 | 480 | static const struct file_operations dev_fops = { |
869d81df DT |
481 | .read = dev_read, |
482 | .write = dev_write, | |
483 | .poll = dev_poll, | |
6038f373 AB |
484 | .owner = THIS_MODULE, |
485 | .llseek = noop_llseek, | |
869d81df DT |
486 | }; |
487 | ||
488 | static struct miscdevice plock_dev_misc = { | |
489 | .minor = MISC_DYNAMIC_MINOR, | |
2402211a | 490 | .name = DLM_PLOCK_MISC_NAME, |
869d81df DT |
491 | .fops = &dev_fops |
492 | }; | |
493 | ||
2402211a | 494 | int dlm_plock_init(void) |
869d81df DT |
495 | { |
496 | int rv; | |
497 | ||
498 | spin_lock_init(&ops_lock); | |
499 | INIT_LIST_HEAD(&send_list); | |
500 | INIT_LIST_HEAD(&recv_list); | |
501 | init_waitqueue_head(&send_wq); | |
502 | init_waitqueue_head(&recv_wq); | |
503 | ||
504 | rv = misc_register(&plock_dev_misc); | |
505 | if (rv) | |
2402211a | 506 | log_print("dlm_plock_init: misc_register failed %d", rv); |
869d81df DT |
507 | return rv; |
508 | } | |
509 | ||
2402211a | 510 | void dlm_plock_exit(void) |
869d81df | 511 | { |
f368ed60 | 512 | misc_deregister(&plock_dev_misc); |
869d81df DT |
513 | } |
514 |