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12#include <linux/smp_lock.h>
13#include "internal.h"
14
15#define AFS_LOCK_GRANTED 0
16#define AFS_LOCK_PENDING 1
17
18static void afs_fl_copy_lock(struct file_lock *new, struct file_lock *fl);
19static void afs_fl_release_private(struct file_lock *fl);
20
21static struct workqueue_struct *afs_lock_manager;
22static DEFINE_MUTEX(afs_lock_manager_mutex);
23
24static const struct file_lock_operations afs_lock_ops = {
25 .fl_copy_lock = afs_fl_copy_lock,
26 .fl_release_private = afs_fl_release_private,
27};
28
29
30
31
32static int afs_init_lock_manager(void)
33{
34 int ret;
35
36 ret = 0;
37 if (!afs_lock_manager) {
38 mutex_lock(&afs_lock_manager_mutex);
39 if (!afs_lock_manager) {
40 afs_lock_manager =
41 create_singlethread_workqueue("kafs_lockd");
42 if (!afs_lock_manager)
43 ret = -ENOMEM;
44 }
45 mutex_unlock(&afs_lock_manager_mutex);
46 }
47 return ret;
48}
49
50
51
52
53void __exit afs_kill_lock_manager(void)
54{
55 if (afs_lock_manager)
56 destroy_workqueue(afs_lock_manager);
57}
58
59
60
61
62void afs_lock_may_be_available(struct afs_vnode *vnode)
63{
64 _enter("{%x:%u}", vnode->fid.vid, vnode->fid.vnode);
65
66 queue_delayed_work(afs_lock_manager, &vnode->lock_work, 0);
67}
68
69
70
71
72
73static void afs_schedule_lock_extension(struct afs_vnode *vnode)
74{
75 queue_delayed_work(afs_lock_manager, &vnode->lock_work,
76 AFS_LOCKWAIT * HZ / 2);
77}
78
79
80
81
82
83
84static void afs_grant_locks(struct afs_vnode *vnode, struct file_lock *fl)
85{
86 struct file_lock *p, *_p;
87
88 list_move_tail(&fl->fl_u.afs.link, &vnode->granted_locks);
89 if (fl->fl_type == F_RDLCK) {
90 list_for_each_entry_safe(p, _p, &vnode->pending_locks,
91 fl_u.afs.link) {
92 if (p->fl_type == F_RDLCK) {
93 p->fl_u.afs.state = AFS_LOCK_GRANTED;
94 list_move_tail(&p->fl_u.afs.link,
95 &vnode->granted_locks);
96 wake_up(&p->fl_wait);
97 }
98 }
99 }
100}
101
102
103
104
105
106
107void afs_lock_work(struct work_struct *work)
108{
109 struct afs_vnode *vnode =
110 container_of(work, struct afs_vnode, lock_work.work);
111 struct file_lock *fl;
112 afs_lock_type_t type;
113 struct key *key;
114 int ret;
115
116 _enter("{%x:%u}", vnode->fid.vid, vnode->fid.vnode);
117
118 spin_lock(&vnode->lock);
119
120 if (test_bit(AFS_VNODE_UNLOCKING, &vnode->flags)) {
121 _debug("unlock");
122 spin_unlock(&vnode->lock);
123
124
125
126 ret = afs_vnode_release_lock(vnode, vnode->unlock_key);
127 if (ret < 0)
128 printk(KERN_WARNING "AFS:"
129 " Failed to release lock on {%x:%x} error %d\n",
130 vnode->fid.vid, vnode->fid.vnode, ret);
131
132 spin_lock(&vnode->lock);
133 key_put(vnode->unlock_key);
134 vnode->unlock_key = NULL;
135 clear_bit(AFS_VNODE_UNLOCKING, &vnode->flags);
136 }
137
138
139
140 if (!list_empty(&vnode->granted_locks)) {
141 _debug("extend");
142
143 if (test_and_set_bit(AFS_VNODE_LOCKING, &vnode->flags))
144 BUG();
145 fl = list_entry(vnode->granted_locks.next,
146 struct file_lock, fl_u.afs.link);
147 key = key_get(fl->fl_file->private_data);
148 spin_unlock(&vnode->lock);
149
150 ret = afs_vnode_extend_lock(vnode, key);
151 clear_bit(AFS_VNODE_LOCKING, &vnode->flags);
152 key_put(key);
153 switch (ret) {
154 case 0:
155 afs_schedule_lock_extension(vnode);
156 break;
157 default:
158
159
160 printk(KERN_WARNING "AFS:"
161 " Failed to extend lock on {%x:%x} error %d\n",
162 vnode->fid.vid, vnode->fid.vnode, ret);
163 queue_delayed_work(afs_lock_manager, &vnode->lock_work,
164 HZ * 10);
165 break;
166 }
167 _leave(" [extend]");
168 return;
169 }
170
171
172
173
174 if (!list_empty(&vnode->pending_locks)) {
175 _debug("get");
176
177 if (test_and_set_bit(AFS_VNODE_LOCKING, &vnode->flags))
178 BUG();
179 fl = list_entry(vnode->pending_locks.next,
180 struct file_lock, fl_u.afs.link);
181 key = key_get(fl->fl_file->private_data);
182 type = (fl->fl_type == F_RDLCK) ?
183 AFS_LOCK_READ : AFS_LOCK_WRITE;
184 spin_unlock(&vnode->lock);
185
186 ret = afs_vnode_set_lock(vnode, key, type);
187 clear_bit(AFS_VNODE_LOCKING, &vnode->flags);
188 switch (ret) {
189 case -EWOULDBLOCK:
190 _debug("blocked");
191 break;
192 case 0:
193 _debug("acquired");
194 if (type == AFS_LOCK_READ)
195 set_bit(AFS_VNODE_READLOCKED, &vnode->flags);
196 else
197 set_bit(AFS_VNODE_WRITELOCKED, &vnode->flags);
198 ret = AFS_LOCK_GRANTED;
199 default:
200 spin_lock(&vnode->lock);
201
202
203 if (list_entry(vnode->pending_locks.next,
204 struct file_lock, fl_u.afs.link) == fl) {
205 fl->fl_u.afs.state = ret;
206 if (ret == AFS_LOCK_GRANTED)
207 afs_grant_locks(vnode, fl);
208 else
209 list_del_init(&fl->fl_u.afs.link);
210 wake_up(&fl->fl_wait);
211 spin_unlock(&vnode->lock);
212 } else {
213 _debug("withdrawn");
214 clear_bit(AFS_VNODE_READLOCKED, &vnode->flags);
215 clear_bit(AFS_VNODE_WRITELOCKED, &vnode->flags);
216 spin_unlock(&vnode->lock);
217 afs_vnode_release_lock(vnode, key);
218 if (!list_empty(&vnode->pending_locks))
219 afs_lock_may_be_available(vnode);
220 }
221 break;
222 }
223 key_put(key);
224 _leave(" [pend]");
225 return;
226 }
227
228
229 spin_unlock(&vnode->lock);
230 _leave(" [no locks]");
231}
232
233
234
235
236
237
238
239static void afs_defer_unlock(struct afs_vnode *vnode, struct key *key)
240{
241 cancel_delayed_work(&vnode->lock_work);
242 if (!test_and_clear_bit(AFS_VNODE_READLOCKED, &vnode->flags) &&
243 !test_and_clear_bit(AFS_VNODE_WRITELOCKED, &vnode->flags))
244 BUG();
245 if (test_and_set_bit(AFS_VNODE_UNLOCKING, &vnode->flags))
246 BUG();
247 vnode->unlock_key = key_get(key);
248 afs_lock_may_be_available(vnode);
249}
250
251
252
253
254static int afs_do_setlk(struct file *file, struct file_lock *fl)
255{
256 struct afs_vnode *vnode = AFS_FS_I(file->f_mapping->host);
257 afs_lock_type_t type;
258 struct key *key = file->private_data;
259 int ret;
260
261 _enter("{%x:%u},%u", vnode->fid.vid, vnode->fid.vnode, fl->fl_type);
262
263
264 if (fl->fl_start != 0 || fl->fl_end != OFFSET_MAX)
265 return -EINVAL;
266
267 ret = afs_init_lock_manager();
268 if (ret < 0)
269 return ret;
270
271 fl->fl_ops = &afs_lock_ops;
272 INIT_LIST_HEAD(&fl->fl_u.afs.link);
273 fl->fl_u.afs.state = AFS_LOCK_PENDING;
274
275 type = (fl->fl_type == F_RDLCK) ? AFS_LOCK_READ : AFS_LOCK_WRITE;
276
277 lock_kernel();
278
279
280
281 ret = afs_vnode_fetch_status(vnode, NULL, key);
282 if (ret < 0)
283 goto error;
284
285 if (vnode->status.lock_count != 0 && !(fl->fl_flags & FL_SLEEP)) {
286 ret = -EAGAIN;
287 goto error;
288 }
289
290 spin_lock(&vnode->lock);
291
292
293
294
295 if (type == AFS_LOCK_READ &&
296 vnode->flags & (1 << AFS_VNODE_READLOCKED)) {
297 _debug("instant readlock");
298 ASSERTCMP(vnode->flags &
299 ((1 << AFS_VNODE_LOCKING) |
300 (1 << AFS_VNODE_WRITELOCKED)), ==, 0);
301 ASSERT(!list_empty(&vnode->granted_locks));
302 goto sharing_existing_lock;
303 }
304
305
306
307 if (list_empty(&vnode->pending_locks) &&
308 list_empty(&vnode->granted_locks)) {
309 _debug("not locked");
310 ASSERTCMP(vnode->flags &
311 ((1 << AFS_VNODE_LOCKING) |
312 (1 << AFS_VNODE_READLOCKED) |
313 (1 << AFS_VNODE_WRITELOCKED)), ==, 0);
314 list_add_tail(&fl->fl_u.afs.link, &vnode->pending_locks);
315 set_bit(AFS_VNODE_LOCKING, &vnode->flags);
316 spin_unlock(&vnode->lock);
317
318 ret = afs_vnode_set_lock(vnode, key, type);
319 clear_bit(AFS_VNODE_LOCKING, &vnode->flags);
320 switch (ret) {
321 case 0:
322 _debug("acquired");
323 goto acquired_server_lock;
324 case -EWOULDBLOCK:
325 _debug("would block");
326 spin_lock(&vnode->lock);
327 ASSERT(list_empty(&vnode->granted_locks));
328 ASSERTCMP(vnode->pending_locks.next, ==,
329 &fl->fl_u.afs.link);
330 goto wait;
331 default:
332 spin_lock(&vnode->lock);
333 list_del_init(&fl->fl_u.afs.link);
334 spin_unlock(&vnode->lock);
335 goto error;
336 }
337 }
338
339
340 _debug("wait local");
341 list_add_tail(&fl->fl_u.afs.link, &vnode->pending_locks);
342wait:
343 if (!(fl->fl_flags & FL_SLEEP)) {
344 _debug("noblock");
345 ret = -EAGAIN;
346 goto abort_attempt;
347 }
348 spin_unlock(&vnode->lock);
349
350
351
352 _debug("sleep");
353 ret = wait_event_interruptible(fl->fl_wait,
354 fl->fl_u.afs.state <= AFS_LOCK_GRANTED);
355 if (fl->fl_u.afs.state <= AFS_LOCK_GRANTED) {
356 ret = fl->fl_u.afs.state;
357 if (ret < 0)
358 goto error;
359 spin_lock(&vnode->lock);
360 goto given_lock;
361 }
362
363
364
365 _debug("intr");
366 ASSERTCMP(ret, ==, -ERESTARTSYS);
367
368 spin_lock(&vnode->lock);
369 if (fl->fl_u.afs.state <= AFS_LOCK_GRANTED) {
370 ret = fl->fl_u.afs.state;
371 if (ret < 0) {
372 spin_unlock(&vnode->lock);
373 goto error;
374 }
375 goto given_lock;
376 }
377
378abort_attempt:
379
380
381 _debug("abort");
382 if (list_empty(&vnode->granted_locks) &&
383 vnode->pending_locks.next == &fl->fl_u.afs.link) {
384 if (vnode->pending_locks.prev != &fl->fl_u.afs.link) {
385
386 list_del_init(&fl->fl_u.afs.link);
387 afs_lock_may_be_available(vnode);
388 }
389 } else {
390 list_del_init(&fl->fl_u.afs.link);
391 }
392 spin_unlock(&vnode->lock);
393 goto error;
394
395acquired_server_lock:
396
397
398 spin_lock(&vnode->lock);
399 afs_schedule_lock_extension(vnode);
400 if (type == AFS_LOCK_READ)
401 set_bit(AFS_VNODE_READLOCKED, &vnode->flags);
402 else
403 set_bit(AFS_VNODE_WRITELOCKED, &vnode->flags);
404sharing_existing_lock:
405
406 fl->fl_u.afs.state = AFS_LOCK_GRANTED;
407 list_move_tail(&fl->fl_u.afs.link, &vnode->granted_locks);
408given_lock:
409
410 ASSERT(!(vnode->flags & (1 << AFS_VNODE_LOCKING)));
411 ASSERT((vnode->flags & ((1 << AFS_VNODE_READLOCKED) |
412 (1 << AFS_VNODE_WRITELOCKED))) != 0);
413 ret = posix_lock_file(file, fl, NULL);
414 if (ret < 0)
415 goto vfs_rejected_lock;
416 spin_unlock(&vnode->lock);
417
418
419
420
421 afs_vnode_fetch_status(vnode, NULL, key);
422
423error:
424 unlock_kernel();
425 _leave(" = %d", ret);
426 return ret;
427
428vfs_rejected_lock:
429
430
431 _debug("vfs refused %d", ret);
432 list_del_init(&fl->fl_u.afs.link);
433 if (list_empty(&vnode->granted_locks))
434 afs_defer_unlock(vnode, key);
435 goto abort_attempt;
436}
437
438
439
440
441static int afs_do_unlk(struct file *file, struct file_lock *fl)
442{
443 struct afs_vnode *vnode = AFS_FS_I(file->f_mapping->host);
444 struct key *key = file->private_data;
445 int ret;
446
447 _enter("{%x:%u},%u", vnode->fid.vid, vnode->fid.vnode, fl->fl_type);
448
449
450 if (fl->fl_start != 0 || fl->fl_end != OFFSET_MAX)
451 return -EINVAL;
452
453 fl->fl_ops = &afs_lock_ops;
454 INIT_LIST_HEAD(&fl->fl_u.afs.link);
455 fl->fl_u.afs.state = AFS_LOCK_PENDING;
456
457 spin_lock(&vnode->lock);
458 ret = posix_lock_file(file, fl, NULL);
459 if (ret < 0) {
460 spin_unlock(&vnode->lock);
461 _leave(" = %d [vfs]", ret);
462 return ret;
463 }
464
465
466 if (list_empty(&vnode->granted_locks))
467 afs_defer_unlock(vnode, key);
468 spin_unlock(&vnode->lock);
469 _leave(" = 0");
470 return 0;
471}
472
473
474
475
476static int afs_do_getlk(struct file *file, struct file_lock *fl)
477{
478 struct afs_vnode *vnode = AFS_FS_I(file->f_mapping->host);
479 struct key *key = file->private_data;
480 int ret, lock_count;
481
482 _enter("");
483
484 fl->fl_type = F_UNLCK;
485
486 mutex_lock(&vnode->vfs_inode.i_mutex);
487
488
489 ret = 0;
490 posix_test_lock(file, fl);
491 if (fl->fl_type == F_UNLCK) {
492
493 ret = afs_vnode_fetch_status(vnode, NULL, key);
494 if (ret < 0)
495 goto error;
496 lock_count = vnode->status.lock_count;
497 if (lock_count) {
498 if (lock_count > 0)
499 fl->fl_type = F_RDLCK;
500 else
501 fl->fl_type = F_WRLCK;
502 fl->fl_start = 0;
503 fl->fl_end = OFFSET_MAX;
504 }
505 }
506
507error:
508 mutex_unlock(&vnode->vfs_inode.i_mutex);
509 _leave(" = %d [%hd]", ret, fl->fl_type);
510 return ret;
511}
512
513
514
515
516int afs_lock(struct file *file, int cmd, struct file_lock *fl)
517{
518 struct afs_vnode *vnode = AFS_FS_I(file->f_dentry->d_inode);
519
520 _enter("{%x:%u},%d,{t=%x,fl=%x,r=%Ld:%Ld}",
521 vnode->fid.vid, vnode->fid.vnode, cmd,
522 fl->fl_type, fl->fl_flags,
523 (long long) fl->fl_start, (long long) fl->fl_end);
524
525
526 if (__mandatory_lock(&vnode->vfs_inode) && fl->fl_type != F_UNLCK)
527 return -ENOLCK;
528
529 if (IS_GETLK(cmd))
530 return afs_do_getlk(file, fl);
531 if (fl->fl_type == F_UNLCK)
532 return afs_do_unlk(file, fl);
533 return afs_do_setlk(file, fl);
534}
535
536
537
538
539int afs_flock(struct file *file, int cmd, struct file_lock *fl)
540{
541 struct afs_vnode *vnode = AFS_FS_I(file->f_dentry->d_inode);
542
543 _enter("{%x:%u},%d,{t=%x,fl=%x}",
544 vnode->fid.vid, vnode->fid.vnode, cmd,
545 fl->fl_type, fl->fl_flags);
546
547
548
549
550
551
552
553
554 if (!(fl->fl_flags & FL_FLOCK))
555 return -ENOLCK;
556
557
558 fl->fl_owner = (fl_owner_t) file;
559 fl->fl_start = 0;
560 fl->fl_end = OFFSET_MAX;
561
562 if (fl->fl_type == F_UNLCK)
563 return afs_do_unlk(file, fl);
564 return afs_do_setlk(file, fl);
565}
566
567
568
569
570
571
572
573static void afs_fl_copy_lock(struct file_lock *new, struct file_lock *fl)
574{
575 _enter("");
576
577 list_add(&new->fl_u.afs.link, &fl->fl_u.afs.link);
578}
579
580
581
582
583
584static void afs_fl_release_private(struct file_lock *fl)
585{
586 _enter("");
587
588 list_del_init(&fl->fl_u.afs.link);
589}
590