Commit | Line | Data |
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e8d6c554 DH |
1 | /* AFS file locking support |
2 | * | |
3 | * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved. | |
4 | * Written by David Howells (dhowells@redhat.com) | |
5 | * | |
6 | * This program is free software; you can redistribute it and/or | |
7 | * modify it under the terms of the GNU General Public License | |
8 | * as published by the Free Software Foundation; either version | |
9 | * 2 of the License, or (at your option) any later version. | |
10 | */ | |
11 | ||
e8d6c554 DH |
12 | #include "internal.h" |
13 | ||
14 | #define AFS_LOCK_GRANTED 0 | |
15 | #define AFS_LOCK_PENDING 1 | |
16 | ||
f044c884 DH |
17 | struct workqueue_struct *afs_lock_manager; |
18 | ||
e8d6c554 DH |
19 | static void afs_fl_copy_lock(struct file_lock *new, struct file_lock *fl); |
20 | static void afs_fl_release_private(struct file_lock *fl); | |
21 | ||
6aed6285 | 22 | static const struct file_lock_operations afs_lock_ops = { |
e8d6c554 DH |
23 | .fl_copy_lock = afs_fl_copy_lock, |
24 | .fl_release_private = afs_fl_release_private, | |
25 | }; | |
26 | ||
e8d6c554 DH |
27 | /* |
28 | * if the callback is broken on this vnode, then the lock may now be available | |
29 | */ | |
30 | void afs_lock_may_be_available(struct afs_vnode *vnode) | |
31 | { | |
32 | _enter("{%x:%u}", vnode->fid.vid, vnode->fid.vnode); | |
33 | ||
34 | queue_delayed_work(afs_lock_manager, &vnode->lock_work, 0); | |
35 | } | |
36 | ||
37 | /* | |
38 | * the lock will time out in 5 minutes unless we extend it, so schedule | |
39 | * extension in a bit less than that time | |
40 | */ | |
41 | static void afs_schedule_lock_extension(struct afs_vnode *vnode) | |
42 | { | |
43 | queue_delayed_work(afs_lock_manager, &vnode->lock_work, | |
44 | AFS_LOCKWAIT * HZ / 2); | |
45 | } | |
46 | ||
ff8e210a DH |
47 | /* |
48 | * grant one or more locks (readlocks are allowed to jump the queue if the | |
49 | * first lock in the queue is itself a readlock) | |
50 | * - the caller must hold the vnode lock | |
51 | */ | |
52 | static void afs_grant_locks(struct afs_vnode *vnode, struct file_lock *fl) | |
53 | { | |
54 | struct file_lock *p, *_p; | |
55 | ||
56 | list_move_tail(&fl->fl_u.afs.link, &vnode->granted_locks); | |
57 | if (fl->fl_type == F_RDLCK) { | |
58 | list_for_each_entry_safe(p, _p, &vnode->pending_locks, | |
59 | fl_u.afs.link) { | |
60 | if (p->fl_type == F_RDLCK) { | |
61 | p->fl_u.afs.state = AFS_LOCK_GRANTED; | |
62 | list_move_tail(&p->fl_u.afs.link, | |
63 | &vnode->granted_locks); | |
64 | wake_up(&p->fl_wait); | |
65 | } | |
66 | } | |
67 | } | |
68 | } | |
69 | ||
d2ddc776 DH |
70 | /* |
71 | * Get a lock on a file | |
72 | */ | |
73 | static int afs_set_lock(struct afs_vnode *vnode, struct key *key, | |
74 | afs_lock_type_t type) | |
75 | { | |
76 | struct afs_fs_cursor fc; | |
77 | int ret; | |
78 | ||
79 | _enter("%s{%x:%u.%u},%x,%u", | |
80 | vnode->volume->name, | |
81 | vnode->fid.vid, | |
82 | vnode->fid.vnode, | |
83 | vnode->fid.unique, | |
84 | key_serial(key), type); | |
85 | ||
86 | ret = -ERESTARTSYS; | |
87 | if (afs_begin_vnode_operation(&fc, vnode, key)) { | |
88 | while (afs_select_fileserver(&fc)) { | |
89 | fc.cb_break = vnode->cb_break + vnode->cb_s_break; | |
90 | afs_fs_set_lock(&fc, type); | |
91 | } | |
92 | ||
93 | afs_check_for_remote_deletion(&fc, fc.vnode); | |
94 | afs_vnode_commit_status(&fc, vnode, fc.cb_break); | |
95 | ret = afs_end_vnode_operation(&fc); | |
96 | } | |
97 | ||
98 | _leave(" = %d", ret); | |
99 | return ret; | |
100 | } | |
101 | ||
102 | /* | |
103 | * Extend a lock on a file | |
104 | */ | |
105 | static int afs_extend_lock(struct afs_vnode *vnode, struct key *key) | |
106 | { | |
107 | struct afs_fs_cursor fc; | |
108 | int ret; | |
109 | ||
110 | _enter("%s{%x:%u.%u},%x", | |
111 | vnode->volume->name, | |
112 | vnode->fid.vid, | |
113 | vnode->fid.vnode, | |
114 | vnode->fid.unique, | |
115 | key_serial(key)); | |
116 | ||
117 | ret = -ERESTARTSYS; | |
118 | if (afs_begin_vnode_operation(&fc, vnode, key)) { | |
119 | while (afs_select_current_fileserver(&fc)) { | |
120 | fc.cb_break = vnode->cb_break + vnode->cb_s_break; | |
121 | afs_fs_extend_lock(&fc); | |
122 | } | |
123 | ||
124 | afs_check_for_remote_deletion(&fc, fc.vnode); | |
125 | afs_vnode_commit_status(&fc, vnode, fc.cb_break); | |
126 | ret = afs_end_vnode_operation(&fc); | |
127 | } | |
128 | ||
129 | _leave(" = %d", ret); | |
130 | return ret; | |
131 | } | |
132 | ||
133 | /* | |
134 | * Release a lock on a file | |
135 | */ | |
136 | static int afs_release_lock(struct afs_vnode *vnode, struct key *key) | |
137 | { | |
138 | struct afs_fs_cursor fc; | |
139 | int ret; | |
140 | ||
141 | _enter("%s{%x:%u.%u},%x", | |
142 | vnode->volume->name, | |
143 | vnode->fid.vid, | |
144 | vnode->fid.vnode, | |
145 | vnode->fid.unique, | |
146 | key_serial(key)); | |
147 | ||
148 | ret = -ERESTARTSYS; | |
149 | if (afs_begin_vnode_operation(&fc, vnode, key)) { | |
150 | while (afs_select_current_fileserver(&fc)) { | |
151 | fc.cb_break = vnode->cb_break + vnode->cb_s_break; | |
152 | afs_fs_release_lock(&fc); | |
153 | } | |
154 | ||
155 | afs_check_for_remote_deletion(&fc, fc.vnode); | |
156 | afs_vnode_commit_status(&fc, vnode, fc.cb_break); | |
157 | ret = afs_end_vnode_operation(&fc); | |
158 | } | |
159 | ||
160 | _leave(" = %d", ret); | |
161 | return ret; | |
162 | } | |
163 | ||
e8d6c554 DH |
164 | /* |
165 | * do work for a lock, including: | |
166 | * - probing for a lock we're waiting on but didn't get immediately | |
167 | * - extending a lock that's close to timing out | |
168 | */ | |
169 | void afs_lock_work(struct work_struct *work) | |
170 | { | |
171 | struct afs_vnode *vnode = | |
172 | container_of(work, struct afs_vnode, lock_work.work); | |
173 | struct file_lock *fl; | |
174 | afs_lock_type_t type; | |
175 | struct key *key; | |
176 | int ret; | |
177 | ||
178 | _enter("{%x:%u}", vnode->fid.vid, vnode->fid.vnode); | |
179 | ||
180 | spin_lock(&vnode->lock); | |
181 | ||
182 | if (test_bit(AFS_VNODE_UNLOCKING, &vnode->flags)) { | |
183 | _debug("unlock"); | |
184 | spin_unlock(&vnode->lock); | |
185 | ||
186 | /* attempt to release the server lock; if it fails, we just | |
187 | * wait 5 minutes and it'll time out anyway */ | |
d2ddc776 | 188 | ret = afs_release_lock(vnode, vnode->unlock_key); |
e8d6c554 DH |
189 | if (ret < 0) |
190 | printk(KERN_WARNING "AFS:" | |
191 | " Failed to release lock on {%x:%x} error %d\n", | |
192 | vnode->fid.vid, vnode->fid.vnode, ret); | |
193 | ||
194 | spin_lock(&vnode->lock); | |
195 | key_put(vnode->unlock_key); | |
196 | vnode->unlock_key = NULL; | |
197 | clear_bit(AFS_VNODE_UNLOCKING, &vnode->flags); | |
198 | } | |
199 | ||
200 | /* if we've got a lock, then it must be time to extend that lock as AFS | |
201 | * locks time out after 5 minutes */ | |
202 | if (!list_empty(&vnode->granted_locks)) { | |
203 | _debug("extend"); | |
204 | ||
205 | if (test_and_set_bit(AFS_VNODE_LOCKING, &vnode->flags)) | |
206 | BUG(); | |
207 | fl = list_entry(vnode->granted_locks.next, | |
208 | struct file_lock, fl_u.afs.link); | |
209 | key = key_get(fl->fl_file->private_data); | |
210 | spin_unlock(&vnode->lock); | |
211 | ||
d2ddc776 | 212 | ret = afs_extend_lock(vnode, key); |
e8d6c554 DH |
213 | clear_bit(AFS_VNODE_LOCKING, &vnode->flags); |
214 | key_put(key); | |
215 | switch (ret) { | |
216 | case 0: | |
217 | afs_schedule_lock_extension(vnode); | |
218 | break; | |
219 | default: | |
220 | /* ummm... we failed to extend the lock - retry | |
221 | * extension shortly */ | |
222 | printk(KERN_WARNING "AFS:" | |
223 | " Failed to extend lock on {%x:%x} error %d\n", | |
224 | vnode->fid.vid, vnode->fid.vnode, ret); | |
225 | queue_delayed_work(afs_lock_manager, &vnode->lock_work, | |
226 | HZ * 10); | |
227 | break; | |
228 | } | |
229 | _leave(" [extend]"); | |
230 | return; | |
231 | } | |
232 | ||
233 | /* if we don't have a granted lock, then we must've been called back by | |
234 | * the server, and so if might be possible to get a lock we're | |
235 | * currently waiting for */ | |
236 | if (!list_empty(&vnode->pending_locks)) { | |
237 | _debug("get"); | |
238 | ||
239 | if (test_and_set_bit(AFS_VNODE_LOCKING, &vnode->flags)) | |
240 | BUG(); | |
241 | fl = list_entry(vnode->pending_locks.next, | |
242 | struct file_lock, fl_u.afs.link); | |
243 | key = key_get(fl->fl_file->private_data); | |
244 | type = (fl->fl_type == F_RDLCK) ? | |
245 | AFS_LOCK_READ : AFS_LOCK_WRITE; | |
246 | spin_unlock(&vnode->lock); | |
247 | ||
d2ddc776 | 248 | ret = afs_set_lock(vnode, key, type); |
e8d6c554 DH |
249 | clear_bit(AFS_VNODE_LOCKING, &vnode->flags); |
250 | switch (ret) { | |
251 | case -EWOULDBLOCK: | |
252 | _debug("blocked"); | |
253 | break; | |
254 | case 0: | |
255 | _debug("acquired"); | |
256 | if (type == AFS_LOCK_READ) | |
257 | set_bit(AFS_VNODE_READLOCKED, &vnode->flags); | |
258 | else | |
259 | set_bit(AFS_VNODE_WRITELOCKED, &vnode->flags); | |
260 | ret = AFS_LOCK_GRANTED; | |
261 | default: | |
262 | spin_lock(&vnode->lock); | |
263 | /* the pending lock may have been withdrawn due to a | |
264 | * signal */ | |
265 | if (list_entry(vnode->pending_locks.next, | |
266 | struct file_lock, fl_u.afs.link) == fl) { | |
267 | fl->fl_u.afs.state = ret; | |
268 | if (ret == AFS_LOCK_GRANTED) | |
ff8e210a | 269 | afs_grant_locks(vnode, fl); |
e8d6c554 DH |
270 | else |
271 | list_del_init(&fl->fl_u.afs.link); | |
272 | wake_up(&fl->fl_wait); | |
273 | spin_unlock(&vnode->lock); | |
274 | } else { | |
275 | _debug("withdrawn"); | |
276 | clear_bit(AFS_VNODE_READLOCKED, &vnode->flags); | |
277 | clear_bit(AFS_VNODE_WRITELOCKED, &vnode->flags); | |
278 | spin_unlock(&vnode->lock); | |
d2ddc776 | 279 | afs_release_lock(vnode, key); |
e8d6c554 DH |
280 | if (!list_empty(&vnode->pending_locks)) |
281 | afs_lock_may_be_available(vnode); | |
282 | } | |
283 | break; | |
284 | } | |
285 | key_put(key); | |
286 | _leave(" [pend]"); | |
287 | return; | |
288 | } | |
289 | ||
290 | /* looks like the lock request was withdrawn on a signal */ | |
291 | spin_unlock(&vnode->lock); | |
292 | _leave(" [no locks]"); | |
293 | } | |
294 | ||
295 | /* | |
296 | * pass responsibility for the unlocking of a vnode on the server to the | |
297 | * manager thread, lest a pending signal in the calling thread interrupt | |
298 | * AF_RXRPC | |
299 | * - the caller must hold the vnode lock | |
300 | */ | |
301 | static void afs_defer_unlock(struct afs_vnode *vnode, struct key *key) | |
302 | { | |
303 | cancel_delayed_work(&vnode->lock_work); | |
304 | if (!test_and_clear_bit(AFS_VNODE_READLOCKED, &vnode->flags) && | |
305 | !test_and_clear_bit(AFS_VNODE_WRITELOCKED, &vnode->flags)) | |
306 | BUG(); | |
307 | if (test_and_set_bit(AFS_VNODE_UNLOCKING, &vnode->flags)) | |
308 | BUG(); | |
309 | vnode->unlock_key = key_get(key); | |
310 | afs_lock_may_be_available(vnode); | |
311 | } | |
312 | ||
313 | /* | |
314 | * request a lock on a file on the server | |
315 | */ | |
316 | static int afs_do_setlk(struct file *file, struct file_lock *fl) | |
317 | { | |
1c8c601a JL |
318 | struct inode *inode = file_inode(file); |
319 | struct afs_vnode *vnode = AFS_FS_I(inode); | |
e8d6c554 DH |
320 | afs_lock_type_t type; |
321 | struct key *key = file->private_data; | |
322 | int ret; | |
323 | ||
324 | _enter("{%x:%u},%u", vnode->fid.vid, vnode->fid.vnode, fl->fl_type); | |
325 | ||
326 | /* only whole-file locks are supported */ | |
327 | if (fl->fl_start != 0 || fl->fl_end != OFFSET_MAX) | |
328 | return -EINVAL; | |
329 | ||
e8d6c554 DH |
330 | fl->fl_ops = &afs_lock_ops; |
331 | INIT_LIST_HEAD(&fl->fl_u.afs.link); | |
332 | fl->fl_u.afs.state = AFS_LOCK_PENDING; | |
333 | ||
334 | type = (fl->fl_type == F_RDLCK) ? AFS_LOCK_READ : AFS_LOCK_WRITE; | |
335 | ||
1c8c601a | 336 | spin_lock(&inode->i_lock); |
e8d6c554 DH |
337 | |
338 | /* make sure we've got a callback on this file and that our view of the | |
339 | * data version is up to date */ | |
c435ee34 | 340 | ret = afs_validate(vnode, key); |
e8d6c554 DH |
341 | if (ret < 0) |
342 | goto error; | |
343 | ||
344 | if (vnode->status.lock_count != 0 && !(fl->fl_flags & FL_SLEEP)) { | |
345 | ret = -EAGAIN; | |
346 | goto error; | |
347 | } | |
348 | ||
349 | spin_lock(&vnode->lock); | |
350 | ||
ff8e210a DH |
351 | /* if we've already got a readlock on the server then we can instantly |
352 | * grant another readlock, irrespective of whether there are any | |
353 | * pending writelocks */ | |
354 | if (type == AFS_LOCK_READ && | |
355 | vnode->flags & (1 << AFS_VNODE_READLOCKED)) { | |
356 | _debug("instant readlock"); | |
357 | ASSERTCMP(vnode->flags & | |
358 | ((1 << AFS_VNODE_LOCKING) | | |
359 | (1 << AFS_VNODE_WRITELOCKED)), ==, 0); | |
360 | ASSERT(!list_empty(&vnode->granted_locks)); | |
361 | goto sharing_existing_lock; | |
362 | } | |
e8d6c554 | 363 | |
ff8e210a DH |
364 | /* if there's no-one else with a lock on this vnode, then we need to |
365 | * ask the server for a lock */ | |
366 | if (list_empty(&vnode->pending_locks) && | |
367 | list_empty(&vnode->granted_locks)) { | |
368 | _debug("not locked"); | |
369 | ASSERTCMP(vnode->flags & | |
370 | ((1 << AFS_VNODE_LOCKING) | | |
371 | (1 << AFS_VNODE_READLOCKED) | | |
372 | (1 << AFS_VNODE_WRITELOCKED)), ==, 0); | |
373 | list_add_tail(&fl->fl_u.afs.link, &vnode->pending_locks); | |
374 | set_bit(AFS_VNODE_LOCKING, &vnode->flags); | |
375 | spin_unlock(&vnode->lock); | |
e8d6c554 | 376 | |
d2ddc776 | 377 | ret = afs_set_lock(vnode, key, type); |
ff8e210a DH |
378 | clear_bit(AFS_VNODE_LOCKING, &vnode->flags); |
379 | switch (ret) { | |
380 | case 0: | |
381 | _debug("acquired"); | |
382 | goto acquired_server_lock; | |
383 | case -EWOULDBLOCK: | |
384 | _debug("would block"); | |
385 | spin_lock(&vnode->lock); | |
386 | ASSERT(list_empty(&vnode->granted_locks)); | |
387 | ASSERTCMP(vnode->pending_locks.next, ==, | |
388 | &fl->fl_u.afs.link); | |
389 | goto wait; | |
390 | default: | |
391 | spin_lock(&vnode->lock); | |
392 | list_del_init(&fl->fl_u.afs.link); | |
393 | spin_unlock(&vnode->lock); | |
394 | goto error; | |
e8d6c554 DH |
395 | } |
396 | } | |
397 | ||
398 | /* otherwise, we need to wait for a local lock to become available */ | |
399 | _debug("wait local"); | |
400 | list_add_tail(&fl->fl_u.afs.link, &vnode->pending_locks); | |
401 | wait: | |
402 | if (!(fl->fl_flags & FL_SLEEP)) { | |
403 | _debug("noblock"); | |
404 | ret = -EAGAIN; | |
405 | goto abort_attempt; | |
406 | } | |
407 | spin_unlock(&vnode->lock); | |
408 | ||
409 | /* now we need to sleep and wait for the lock manager thread to get the | |
410 | * lock from the server */ | |
411 | _debug("sleep"); | |
412 | ret = wait_event_interruptible(fl->fl_wait, | |
413 | fl->fl_u.afs.state <= AFS_LOCK_GRANTED); | |
414 | if (fl->fl_u.afs.state <= AFS_LOCK_GRANTED) { | |
415 | ret = fl->fl_u.afs.state; | |
416 | if (ret < 0) | |
417 | goto error; | |
418 | spin_lock(&vnode->lock); | |
419 | goto given_lock; | |
420 | } | |
421 | ||
422 | /* we were interrupted, but someone may still be in the throes of | |
423 | * giving us the lock */ | |
424 | _debug("intr"); | |
425 | ASSERTCMP(ret, ==, -ERESTARTSYS); | |
426 | ||
427 | spin_lock(&vnode->lock); | |
428 | if (fl->fl_u.afs.state <= AFS_LOCK_GRANTED) { | |
429 | ret = fl->fl_u.afs.state; | |
430 | if (ret < 0) { | |
431 | spin_unlock(&vnode->lock); | |
432 | goto error; | |
433 | } | |
434 | goto given_lock; | |
435 | } | |
436 | ||
437 | abort_attempt: | |
438 | /* we aren't going to get the lock, either because we're unwilling to | |
439 | * wait, or because some signal happened */ | |
440 | _debug("abort"); | |
441 | if (list_empty(&vnode->granted_locks) && | |
442 | vnode->pending_locks.next == &fl->fl_u.afs.link) { | |
443 | if (vnode->pending_locks.prev != &fl->fl_u.afs.link) { | |
444 | /* kick the next pending lock into having a go */ | |
445 | list_del_init(&fl->fl_u.afs.link); | |
446 | afs_lock_may_be_available(vnode); | |
447 | } | |
448 | } else { | |
449 | list_del_init(&fl->fl_u.afs.link); | |
450 | } | |
451 | spin_unlock(&vnode->lock); | |
452 | goto error; | |
453 | ||
454 | acquired_server_lock: | |
455 | /* we've acquired a server lock, but it needs to be renewed after 5 | |
456 | * mins */ | |
457 | spin_lock(&vnode->lock); | |
458 | afs_schedule_lock_extension(vnode); | |
459 | if (type == AFS_LOCK_READ) | |
460 | set_bit(AFS_VNODE_READLOCKED, &vnode->flags); | |
461 | else | |
462 | set_bit(AFS_VNODE_WRITELOCKED, &vnode->flags); | |
463 | sharing_existing_lock: | |
464 | /* the lock has been granted as far as we're concerned... */ | |
465 | fl->fl_u.afs.state = AFS_LOCK_GRANTED; | |
466 | list_move_tail(&fl->fl_u.afs.link, &vnode->granted_locks); | |
467 | given_lock: | |
468 | /* ... but we do still need to get the VFS's blessing */ | |
469 | ASSERT(!(vnode->flags & (1 << AFS_VNODE_LOCKING))); | |
470 | ASSERT((vnode->flags & ((1 << AFS_VNODE_READLOCKED) | | |
471 | (1 << AFS_VNODE_WRITELOCKED))) != 0); | |
472 | ret = posix_lock_file(file, fl, NULL); | |
473 | if (ret < 0) | |
474 | goto vfs_rejected_lock; | |
475 | spin_unlock(&vnode->lock); | |
476 | ||
477 | /* again, make sure we've got a callback on this file and, again, make | |
478 | * sure that our view of the data version is up to date (we ignore | |
479 | * errors incurred here and deal with the consequences elsewhere) */ | |
d2ddc776 | 480 | afs_validate(vnode, key); |
e8d6c554 DH |
481 | |
482 | error: | |
1c8c601a | 483 | spin_unlock(&inode->i_lock); |
e8d6c554 DH |
484 | _leave(" = %d", ret); |
485 | return ret; | |
486 | ||
487 | vfs_rejected_lock: | |
488 | /* the VFS rejected the lock we just obtained, so we have to discard | |
489 | * what we just got */ | |
490 | _debug("vfs refused %d", ret); | |
491 | list_del_init(&fl->fl_u.afs.link); | |
492 | if (list_empty(&vnode->granted_locks)) | |
493 | afs_defer_unlock(vnode, key); | |
e8d6c554 DH |
494 | goto abort_attempt; |
495 | } | |
496 | ||
497 | /* | |
498 | * unlock on a file on the server | |
499 | */ | |
500 | static int afs_do_unlk(struct file *file, struct file_lock *fl) | |
501 | { | |
502 | struct afs_vnode *vnode = AFS_FS_I(file->f_mapping->host); | |
503 | struct key *key = file->private_data; | |
504 | int ret; | |
505 | ||
506 | _enter("{%x:%u},%u", vnode->fid.vid, vnode->fid.vnode, fl->fl_type); | |
507 | ||
508 | /* only whole-file unlocks are supported */ | |
509 | if (fl->fl_start != 0 || fl->fl_end != OFFSET_MAX) | |
510 | return -EINVAL; | |
511 | ||
512 | fl->fl_ops = &afs_lock_ops; | |
513 | INIT_LIST_HEAD(&fl->fl_u.afs.link); | |
514 | fl->fl_u.afs.state = AFS_LOCK_PENDING; | |
515 | ||
516 | spin_lock(&vnode->lock); | |
517 | ret = posix_lock_file(file, fl, NULL); | |
518 | if (ret < 0) { | |
519 | spin_unlock(&vnode->lock); | |
520 | _leave(" = %d [vfs]", ret); | |
521 | return ret; | |
522 | } | |
523 | ||
524 | /* discard the server lock only if all granted locks are gone */ | |
525 | if (list_empty(&vnode->granted_locks)) | |
526 | afs_defer_unlock(vnode, key); | |
527 | spin_unlock(&vnode->lock); | |
528 | _leave(" = 0"); | |
529 | return 0; | |
530 | } | |
531 | ||
532 | /* | |
533 | * return information about a lock we currently hold, if indeed we hold one | |
534 | */ | |
535 | static int afs_do_getlk(struct file *file, struct file_lock *fl) | |
536 | { | |
537 | struct afs_vnode *vnode = AFS_FS_I(file->f_mapping->host); | |
538 | struct key *key = file->private_data; | |
539 | int ret, lock_count; | |
540 | ||
541 | _enter(""); | |
542 | ||
543 | fl->fl_type = F_UNLCK; | |
544 | ||
5955102c | 545 | inode_lock(&vnode->vfs_inode); |
e8d6c554 DH |
546 | |
547 | /* check local lock records first */ | |
548 | ret = 0; | |
275afcac AM |
549 | posix_test_lock(file, fl); |
550 | if (fl->fl_type == F_UNLCK) { | |
e8d6c554 | 551 | /* no local locks; consult the server */ |
d2ddc776 | 552 | ret = afs_fetch_status(vnode, key); |
e8d6c554 DH |
553 | if (ret < 0) |
554 | goto error; | |
555 | lock_count = vnode->status.lock_count; | |
556 | if (lock_count) { | |
557 | if (lock_count > 0) | |
558 | fl->fl_type = F_RDLCK; | |
559 | else | |
560 | fl->fl_type = F_WRLCK; | |
561 | fl->fl_start = 0; | |
562 | fl->fl_end = OFFSET_MAX; | |
563 | } | |
564 | } | |
565 | ||
566 | error: | |
5955102c | 567 | inode_unlock(&vnode->vfs_inode); |
e8d6c554 DH |
568 | _leave(" = %d [%hd]", ret, fl->fl_type); |
569 | return ret; | |
570 | } | |
571 | ||
572 | /* | |
573 | * manage POSIX locks on a file | |
574 | */ | |
575 | int afs_lock(struct file *file, int cmd, struct file_lock *fl) | |
576 | { | |
496ad9aa | 577 | struct afs_vnode *vnode = AFS_FS_I(file_inode(file)); |
e8d6c554 DH |
578 | |
579 | _enter("{%x:%u},%d,{t=%x,fl=%x,r=%Ld:%Ld}", | |
580 | vnode->fid.vid, vnode->fid.vnode, cmd, | |
581 | fl->fl_type, fl->fl_flags, | |
582 | (long long) fl->fl_start, (long long) fl->fl_end); | |
583 | ||
584 | /* AFS doesn't support mandatory locks */ | |
fc5846e5 | 585 | if (__mandatory_lock(&vnode->vfs_inode) && fl->fl_type != F_UNLCK) |
e8d6c554 DH |
586 | return -ENOLCK; |
587 | ||
588 | if (IS_GETLK(cmd)) | |
589 | return afs_do_getlk(file, fl); | |
590 | if (fl->fl_type == F_UNLCK) | |
591 | return afs_do_unlk(file, fl); | |
592 | return afs_do_setlk(file, fl); | |
593 | } | |
594 | ||
595 | /* | |
596 | * manage FLOCK locks on a file | |
597 | */ | |
598 | int afs_flock(struct file *file, int cmd, struct file_lock *fl) | |
599 | { | |
496ad9aa | 600 | struct afs_vnode *vnode = AFS_FS_I(file_inode(file)); |
e8d6c554 DH |
601 | |
602 | _enter("{%x:%u},%d,{t=%x,fl=%x}", | |
603 | vnode->fid.vid, vnode->fid.vnode, cmd, | |
604 | fl->fl_type, fl->fl_flags); | |
605 | ||
606 | /* | |
607 | * No BSD flocks over NFS allowed. | |
608 | * Note: we could try to fake a POSIX lock request here by | |
609 | * using ((u32) filp | 0x80000000) or some such as the pid. | |
610 | * Not sure whether that would be unique, though, or whether | |
611 | * that would break in other places. | |
612 | */ | |
613 | if (!(fl->fl_flags & FL_FLOCK)) | |
614 | return -ENOLCK; | |
615 | ||
616 | /* we're simulating flock() locks using posix locks on the server */ | |
e8d6c554 DH |
617 | if (fl->fl_type == F_UNLCK) |
618 | return afs_do_unlk(file, fl); | |
619 | return afs_do_setlk(file, fl); | |
620 | } | |
621 | ||
622 | /* | |
623 | * the POSIX lock management core VFS code copies the lock record and adds the | |
624 | * copy into its own list, so we need to add that copy to the vnode's lock | |
625 | * queue in the same place as the original (which will be deleted shortly | |
626 | * after) | |
627 | */ | |
628 | static void afs_fl_copy_lock(struct file_lock *new, struct file_lock *fl) | |
629 | { | |
630 | _enter(""); | |
631 | ||
632 | list_add(&new->fl_u.afs.link, &fl->fl_u.afs.link); | |
633 | } | |
634 | ||
635 | /* | |
636 | * need to remove this lock from the vnode queue when it's removed from the | |
637 | * VFS's list | |
638 | */ | |
639 | static void afs_fl_release_private(struct file_lock *fl) | |
640 | { | |
641 | _enter(""); | |
642 | ||
643 | list_del_init(&fl->fl_u.afs.link); | |
644 | } |