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); | |
0fafdc9f | 173 | struct file_lock *fl, *next; |
e8d6c554 DH |
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 | ||
0fafdc9f DH |
182 | again: |
183 | _debug("wstate %u for %p", vnode->lock_state, vnode); | |
184 | switch (vnode->lock_state) { | |
185 | case AFS_VNODE_LOCK_NEED_UNLOCK: | |
e8d6c554 | 186 | _debug("unlock"); |
0fafdc9f | 187 | vnode->lock_state = AFS_VNODE_LOCK_UNLOCKING; |
e8d6c554 DH |
188 | spin_unlock(&vnode->lock); |
189 | ||
190 | /* attempt to release the server lock; if it fails, we just | |
0fafdc9f DH |
191 | * wait 5 minutes and it'll expire anyway */ |
192 | ret = afs_release_lock(vnode, vnode->lock_key); | |
e8d6c554 DH |
193 | if (ret < 0) |
194 | printk(KERN_WARNING "AFS:" | |
195 | " Failed to release lock on {%x:%x} error %d\n", | |
196 | vnode->fid.vid, vnode->fid.vnode, ret); | |
197 | ||
198 | spin_lock(&vnode->lock); | |
0fafdc9f DH |
199 | key_put(vnode->lock_key); |
200 | vnode->lock_key = NULL; | |
201 | vnode->lock_state = AFS_VNODE_LOCK_NONE; | |
202 | ||
203 | if (list_empty(&vnode->pending_locks)) { | |
204 | spin_unlock(&vnode->lock); | |
205 | return; | |
206 | } | |
207 | ||
208 | /* The new front of the queue now owns the state variables. */ | |
209 | next = list_entry(vnode->pending_locks.next, | |
210 | struct file_lock, fl_u.afs.link); | |
211 | vnode->lock_key = afs_file_key(next->fl_file); | |
212 | vnode->lock_type = (next->fl_type == F_RDLCK) ? AFS_LOCK_READ : AFS_LOCK_WRITE; | |
213 | vnode->lock_state = AFS_VNODE_LOCK_WAITING_FOR_CB; | |
214 | goto again; | |
e8d6c554 | 215 | |
0fafdc9f DH |
216 | /* If we've already got a lock, then it must be time to extend that |
217 | * lock as AFS locks time out after 5 minutes. | |
218 | */ | |
219 | case AFS_VNODE_LOCK_GRANTED: | |
e8d6c554 DH |
220 | _debug("extend"); |
221 | ||
0fafdc9f DH |
222 | ASSERT(!list_empty(&vnode->granted_locks)); |
223 | ||
224 | key = key_get(vnode->lock_key); | |
225 | vnode->lock_state = AFS_VNODE_LOCK_EXTENDING; | |
e8d6c554 DH |
226 | spin_unlock(&vnode->lock); |
227 | ||
0fafdc9f | 228 | ret = afs_extend_lock(vnode, key); /* RPC */ |
e8d6c554 | 229 | key_put(key); |
0fafdc9f DH |
230 | |
231 | if (ret < 0) | |
232 | pr_warning("AFS: Failed to extend lock on {%x:%x} error %d\n", | |
233 | vnode->fid.vid, vnode->fid.vnode, ret); | |
234 | ||
235 | spin_lock(&vnode->lock); | |
236 | ||
237 | if (vnode->lock_state != AFS_VNODE_LOCK_EXTENDING) | |
238 | goto again; | |
239 | vnode->lock_state = AFS_VNODE_LOCK_GRANTED; | |
240 | ||
241 | if (ret == 0) | |
e8d6c554 | 242 | afs_schedule_lock_extension(vnode); |
0fafdc9f | 243 | else |
e8d6c554 DH |
244 | queue_delayed_work(afs_lock_manager, &vnode->lock_work, |
245 | HZ * 10); | |
0fafdc9f DH |
246 | spin_unlock(&vnode->lock); |
247 | _leave(" [ext]"); | |
e8d6c554 | 248 | return; |
e8d6c554 | 249 | |
0fafdc9f DH |
250 | /* If we don't have a granted lock, then we must've been called |
251 | * back by the server, and so if might be possible to get a | |
252 | * lock we're currently waiting for. | |
253 | */ | |
254 | case AFS_VNODE_LOCK_WAITING_FOR_CB: | |
e8d6c554 DH |
255 | _debug("get"); |
256 | ||
0fafdc9f DH |
257 | key = key_get(vnode->lock_key); |
258 | type = vnode->lock_type; | |
259 | vnode->lock_state = AFS_VNODE_LOCK_SETTING; | |
e8d6c554 DH |
260 | spin_unlock(&vnode->lock); |
261 | ||
0fafdc9f DH |
262 | ret = afs_set_lock(vnode, key, type); /* RPC */ |
263 | key_put(key); | |
264 | ||
265 | spin_lock(&vnode->lock); | |
e8d6c554 DH |
266 | switch (ret) { |
267 | case -EWOULDBLOCK: | |
268 | _debug("blocked"); | |
269 | break; | |
270 | case 0: | |
271 | _debug("acquired"); | |
0fafdc9f DH |
272 | vnode->lock_state = AFS_VNODE_LOCK_GRANTED; |
273 | /* Fall through */ | |
e8d6c554 | 274 | default: |
0fafdc9f DH |
275 | /* Pass the lock or the error onto the first locker in |
276 | * the list - if they're looking for this type of lock. | |
277 | * If they're not, we assume that whoever asked for it | |
278 | * took a signal. | |
279 | */ | |
280 | if (list_empty(&vnode->pending_locks)) { | |
e8d6c554 | 281 | _debug("withdrawn"); |
0fafdc9f DH |
282 | vnode->lock_state = AFS_VNODE_LOCK_NEED_UNLOCK; |
283 | goto again; | |
e8d6c554 | 284 | } |
0fafdc9f DH |
285 | |
286 | fl = list_entry(vnode->pending_locks.next, | |
287 | struct file_lock, fl_u.afs.link); | |
288 | type = (fl->fl_type == F_RDLCK) ? AFS_LOCK_READ : AFS_LOCK_WRITE; | |
289 | if (vnode->lock_type != type) { | |
290 | _debug("changed"); | |
291 | vnode->lock_state = AFS_VNODE_LOCK_NEED_UNLOCK; | |
292 | goto again; | |
293 | } | |
294 | ||
295 | fl->fl_u.afs.state = ret; | |
296 | if (ret == 0) | |
297 | afs_grant_locks(vnode, fl); | |
298 | else | |
299 | list_del_init(&fl->fl_u.afs.link); | |
300 | wake_up(&fl->fl_wait); | |
301 | spin_unlock(&vnode->lock); | |
302 | _leave(" [granted]"); | |
303 | return; | |
e8d6c554 | 304 | } |
0fafdc9f DH |
305 | |
306 | default: | |
307 | /* Looks like a lock request was withdrawn. */ | |
308 | spin_unlock(&vnode->lock); | |
309 | _leave(" [no]"); | |
e8d6c554 DH |
310 | return; |
311 | } | |
e8d6c554 DH |
312 | } |
313 | ||
314 | /* | |
315 | * pass responsibility for the unlocking of a vnode on the server to the | |
316 | * manager thread, lest a pending signal in the calling thread interrupt | |
317 | * AF_RXRPC | |
318 | * - the caller must hold the vnode lock | |
319 | */ | |
0fafdc9f | 320 | static void afs_defer_unlock(struct afs_vnode *vnode) |
e8d6c554 | 321 | { |
0fafdc9f DH |
322 | _enter(""); |
323 | ||
324 | if (vnode->lock_state == AFS_VNODE_LOCK_GRANTED || | |
325 | vnode->lock_state == AFS_VNODE_LOCK_EXTENDING) { | |
326 | cancel_delayed_work(&vnode->lock_work); | |
327 | ||
328 | vnode->lock_state = AFS_VNODE_LOCK_NEED_UNLOCK; | |
329 | afs_lock_may_be_available(vnode); | |
330 | } | |
331 | } | |
332 | ||
333 | /* | |
334 | * Check that our view of the file metadata is up to date and check to see | |
335 | * whether we think that we have a locking permit. | |
336 | */ | |
337 | static int afs_do_setlk_check(struct afs_vnode *vnode, struct key *key, | |
338 | afs_lock_type_t type, bool can_sleep) | |
339 | { | |
340 | afs_access_t access; | |
341 | int ret; | |
342 | ||
343 | /* Make sure we've got a callback on this file and that our view of the | |
344 | * data version is up to date. | |
345 | */ | |
346 | ret = afs_validate(vnode, key); | |
347 | if (ret < 0) | |
348 | return ret; | |
349 | ||
350 | /* Check the permission set to see if we're actually going to be | |
351 | * allowed to get a lock on this file. | |
352 | */ | |
353 | ret = afs_check_permit(vnode, key, &access); | |
354 | if (ret < 0) | |
355 | return ret; | |
356 | ||
357 | /* At a rough estimation, you need LOCK, WRITE or INSERT perm to | |
358 | * read-lock a file and WRITE or INSERT perm to write-lock a file. | |
359 | * | |
360 | * We can't rely on the server to do this for us since if we want to | |
361 | * share a read lock that we already have, we won't go the server. | |
362 | */ | |
363 | if (type == AFS_LOCK_READ) { | |
364 | if (!(access & (AFS_ACE_INSERT | AFS_ACE_WRITE | AFS_ACE_LOCK))) | |
365 | return -EACCES; | |
366 | if (vnode->status.lock_count == -1 && !can_sleep) | |
367 | return -EAGAIN; /* Write locked */ | |
368 | } else { | |
369 | if (!(access & (AFS_ACE_INSERT | AFS_ACE_WRITE))) | |
370 | return -EACCES; | |
371 | if (vnode->status.lock_count != 0 && !can_sleep) | |
372 | return -EAGAIN; /* Locked */ | |
373 | } | |
374 | ||
375 | return 0; | |
376 | } | |
377 | ||
378 | /* | |
379 | * Remove the front runner from the pending queue. | |
380 | * - The caller must hold vnode->lock. | |
381 | */ | |
382 | static void afs_dequeue_lock(struct afs_vnode *vnode, struct file_lock *fl) | |
383 | { | |
384 | struct file_lock *next; | |
385 | ||
386 | _enter(""); | |
387 | ||
388 | /* ->lock_type, ->lock_key and ->lock_state only belong to this | |
389 | * file_lock if we're at the front of the pending queue or if we have | |
390 | * the lock granted or if the lock_state is NEED_UNLOCK or UNLOCKING. | |
391 | */ | |
392 | if (vnode->granted_locks.next == &fl->fl_u.afs.link && | |
393 | vnode->granted_locks.prev == &fl->fl_u.afs.link) { | |
394 | list_del_init(&fl->fl_u.afs.link); | |
395 | afs_defer_unlock(vnode); | |
396 | return; | |
397 | } | |
398 | ||
399 | if (!list_empty(&vnode->granted_locks) || | |
400 | vnode->pending_locks.next != &fl->fl_u.afs.link) { | |
401 | list_del_init(&fl->fl_u.afs.link); | |
402 | return; | |
403 | } | |
404 | ||
405 | list_del_init(&fl->fl_u.afs.link); | |
406 | key_put(vnode->lock_key); | |
407 | vnode->lock_key = NULL; | |
408 | vnode->lock_state = AFS_VNODE_LOCK_NONE; | |
409 | ||
410 | if (list_empty(&vnode->pending_locks)) | |
411 | return; | |
412 | ||
413 | /* The new front of the queue now owns the state variables. */ | |
414 | next = list_entry(vnode->pending_locks.next, | |
415 | struct file_lock, fl_u.afs.link); | |
416 | vnode->lock_key = afs_file_key(next->fl_file); | |
417 | vnode->lock_type = (next->fl_type == F_RDLCK) ? AFS_LOCK_READ : AFS_LOCK_WRITE; | |
418 | vnode->lock_state = AFS_VNODE_LOCK_WAITING_FOR_CB; | |
e8d6c554 DH |
419 | afs_lock_may_be_available(vnode); |
420 | } | |
421 | ||
422 | /* | |
423 | * request a lock on a file on the server | |
424 | */ | |
425 | static int afs_do_setlk(struct file *file, struct file_lock *fl) | |
426 | { | |
0fafdc9f | 427 | struct inode *inode = locks_inode(file); |
1c8c601a | 428 | struct afs_vnode *vnode = AFS_FS_I(inode); |
e8d6c554 | 429 | afs_lock_type_t type; |
215804a9 | 430 | struct key *key = afs_file_key(file); |
e8d6c554 DH |
431 | int ret; |
432 | ||
433 | _enter("{%x:%u},%u", vnode->fid.vid, vnode->fid.vnode, fl->fl_type); | |
434 | ||
435 | /* only whole-file locks are supported */ | |
436 | if (fl->fl_start != 0 || fl->fl_end != OFFSET_MAX) | |
437 | return -EINVAL; | |
438 | ||
e8d6c554 DH |
439 | fl->fl_ops = &afs_lock_ops; |
440 | INIT_LIST_HEAD(&fl->fl_u.afs.link); | |
441 | fl->fl_u.afs.state = AFS_LOCK_PENDING; | |
442 | ||
443 | type = (fl->fl_type == F_RDLCK) ? AFS_LOCK_READ : AFS_LOCK_WRITE; | |
444 | ||
0fafdc9f | 445 | ret = afs_do_setlk_check(vnode, key, type, fl->fl_flags & FL_SLEEP); |
e8d6c554 | 446 | if (ret < 0) |
0fafdc9f | 447 | return ret; |
e8d6c554 DH |
448 | |
449 | spin_lock(&vnode->lock); | |
450 | ||
0fafdc9f | 451 | /* If we've already got a readlock on the server then we instantly |
ff8e210a | 452 | * grant another readlock, irrespective of whether there are any |
0fafdc9f DH |
453 | * pending writelocks. |
454 | */ | |
ff8e210a | 455 | if (type == AFS_LOCK_READ && |
0fafdc9f DH |
456 | vnode->lock_state == AFS_VNODE_LOCK_GRANTED && |
457 | vnode->lock_type == AFS_LOCK_READ) { | |
ff8e210a | 458 | _debug("instant readlock"); |
ff8e210a | 459 | ASSERT(!list_empty(&vnode->granted_locks)); |
0fafdc9f | 460 | goto share_existing_lock; |
ff8e210a | 461 | } |
e8d6c554 | 462 | |
0fafdc9f | 463 | list_add_tail(&fl->fl_u.afs.link, &vnode->pending_locks); |
e8d6c554 | 464 | |
0fafdc9f DH |
465 | if (vnode->lock_state != AFS_VNODE_LOCK_NONE) |
466 | goto need_to_wait; | |
e8d6c554 | 467 | |
0fafdc9f DH |
468 | /* We don't have a lock on this vnode and we aren't currently waiting |
469 | * for one either, so ask the server for a lock. | |
470 | * | |
471 | * Note that we need to be careful if we get interrupted by a signal | |
472 | * after dispatching the request as we may still get the lock, even | |
473 | * though we don't wait for the reply (it's not too bad a problem - the | |
474 | * lock will expire in 10 mins anyway). | |
475 | */ | |
476 | _debug("not locked"); | |
477 | vnode->lock_key = key_get(key); | |
478 | vnode->lock_type = type; | |
479 | vnode->lock_state = AFS_VNODE_LOCK_SETTING; | |
e8d6c554 DH |
480 | spin_unlock(&vnode->lock); |
481 | ||
0fafdc9f | 482 | ret = afs_set_lock(vnode, key, type); /* RPC */ |
e8d6c554 DH |
483 | |
484 | spin_lock(&vnode->lock); | |
0fafdc9f DH |
485 | switch (ret) { |
486 | default: | |
487 | goto abort_attempt; | |
e8d6c554 | 488 | |
0fafdc9f DH |
489 | case -EWOULDBLOCK: |
490 | /* The server doesn't have a lock-waiting queue, so the client | |
491 | * will have to retry. The server will break the outstanding | |
492 | * callbacks on a file when a lock is released. | |
493 | */ | |
494 | _debug("would block"); | |
495 | ASSERT(list_empty(&vnode->granted_locks)); | |
496 | ASSERTCMP(vnode->pending_locks.next, ==, &fl->fl_u.afs.link); | |
497 | vnode->lock_state = AFS_VNODE_LOCK_WAITING_FOR_CB; | |
498 | goto need_to_wait; | |
499 | ||
500 | case 0: | |
501 | _debug("acquired"); | |
502 | break; | |
e8d6c554 | 503 | } |
e8d6c554 | 504 | |
e8d6c554 DH |
505 | /* we've acquired a server lock, but it needs to be renewed after 5 |
506 | * mins */ | |
0fafdc9f | 507 | vnode->lock_state = AFS_VNODE_LOCK_GRANTED; |
e8d6c554 | 508 | afs_schedule_lock_extension(vnode); |
0fafdc9f DH |
509 | |
510 | share_existing_lock: | |
e8d6c554 DH |
511 | /* the lock has been granted as far as we're concerned... */ |
512 | fl->fl_u.afs.state = AFS_LOCK_GRANTED; | |
513 | list_move_tail(&fl->fl_u.afs.link, &vnode->granted_locks); | |
0fafdc9f | 514 | |
e8d6c554 DH |
515 | given_lock: |
516 | /* ... but we do still need to get the VFS's blessing */ | |
0fafdc9f DH |
517 | spin_unlock(&vnode->lock); |
518 | ||
e8d6c554 DH |
519 | ret = posix_lock_file(file, fl, NULL); |
520 | if (ret < 0) | |
521 | goto vfs_rejected_lock; | |
e8d6c554 | 522 | |
0fafdc9f | 523 | /* Again, make sure we've got a callback on this file and, again, make |
e8d6c554 | 524 | * sure that our view of the data version is up to date (we ignore |
0fafdc9f DH |
525 | * errors incurred here and deal with the consequences elsewhere). |
526 | */ | |
d2ddc776 | 527 | afs_validate(vnode, key); |
0fafdc9f DH |
528 | _leave(" = 0"); |
529 | return 0; | |
e8d6c554 | 530 | |
0fafdc9f DH |
531 | need_to_wait: |
532 | /* We're going to have to wait. Either this client doesn't have a lock | |
533 | * on the server yet and we need to wait for a callback to occur, or | |
534 | * the client does have a lock on the server, but it belongs to some | |
535 | * other process(es) and is incompatible with the lock we want. | |
536 | */ | |
537 | ret = -EAGAIN; | |
538 | if (fl->fl_flags & FL_SLEEP) { | |
539 | spin_unlock(&vnode->lock); | |
540 | ||
541 | _debug("sleep"); | |
542 | ret = wait_event_interruptible(fl->fl_wait, | |
543 | fl->fl_u.afs.state != AFS_LOCK_PENDING); | |
544 | ||
545 | spin_lock(&vnode->lock); | |
546 | } | |
547 | ||
548 | if (fl->fl_u.afs.state == AFS_LOCK_GRANTED) | |
549 | goto given_lock; | |
550 | if (fl->fl_u.afs.state < 0) | |
551 | ret = fl->fl_u.afs.state; | |
552 | ||
553 | abort_attempt: | |
554 | /* we aren't going to get the lock, either because we're unwilling to | |
555 | * wait, or because some signal happened */ | |
556 | _debug("abort"); | |
557 | afs_dequeue_lock(vnode, fl); | |
558 | ||
559 | error_unlock: | |
560 | spin_unlock(&vnode->lock); | |
e8d6c554 DH |
561 | _leave(" = %d", ret); |
562 | return ret; | |
563 | ||
564 | vfs_rejected_lock: | |
0fafdc9f DH |
565 | /* The VFS rejected the lock we just obtained, so we have to discard |
566 | * what we just got. We defer this to the lock manager work item to | |
567 | * deal with. | |
568 | */ | |
e8d6c554 | 569 | _debug("vfs refused %d", ret); |
0fafdc9f | 570 | spin_lock(&vnode->lock); |
e8d6c554 DH |
571 | list_del_init(&fl->fl_u.afs.link); |
572 | if (list_empty(&vnode->granted_locks)) | |
0fafdc9f DH |
573 | afs_defer_unlock(vnode); |
574 | goto error_unlock; | |
e8d6c554 DH |
575 | } |
576 | ||
577 | /* | |
578 | * unlock on a file on the server | |
579 | */ | |
580 | static int afs_do_unlk(struct file *file, struct file_lock *fl) | |
581 | { | |
0fafdc9f | 582 | struct afs_vnode *vnode = AFS_FS_I(locks_inode(file)); |
e8d6c554 DH |
583 | int ret; |
584 | ||
585 | _enter("{%x:%u},%u", vnode->fid.vid, vnode->fid.vnode, fl->fl_type); | |
586 | ||
0fafdc9f DH |
587 | /* Flush all pending writes before doing anything with locks. */ |
588 | vfs_fsync(file, 0); | |
589 | ||
e8d6c554 DH |
590 | /* only whole-file unlocks are supported */ |
591 | if (fl->fl_start != 0 || fl->fl_end != OFFSET_MAX) | |
592 | return -EINVAL; | |
593 | ||
e8d6c554 | 594 | ret = posix_lock_file(file, fl, NULL); |
0fafdc9f DH |
595 | _leave(" = %d [%u]", ret, vnode->lock_state); |
596 | return ret; | |
e8d6c554 DH |
597 | } |
598 | ||
599 | /* | |
600 | * return information about a lock we currently hold, if indeed we hold one | |
601 | */ | |
602 | static int afs_do_getlk(struct file *file, struct file_lock *fl) | |
603 | { | |
0fafdc9f | 604 | struct afs_vnode *vnode = AFS_FS_I(locks_inode(file)); |
215804a9 | 605 | struct key *key = afs_file_key(file); |
e8d6c554 DH |
606 | int ret, lock_count; |
607 | ||
608 | _enter(""); | |
609 | ||
610 | fl->fl_type = F_UNLCK; | |
611 | ||
e8d6c554 | 612 | /* check local lock records first */ |
275afcac AM |
613 | posix_test_lock(file, fl); |
614 | if (fl->fl_type == F_UNLCK) { | |
e8d6c554 | 615 | /* no local locks; consult the server */ |
d2ddc776 | 616 | ret = afs_fetch_status(vnode, key); |
e8d6c554 DH |
617 | if (ret < 0) |
618 | goto error; | |
0fafdc9f DH |
619 | |
620 | lock_count = READ_ONCE(vnode->status.lock_count); | |
621 | if (lock_count > 0) | |
622 | fl->fl_type = F_RDLCK; | |
623 | else | |
624 | fl->fl_type = F_WRLCK; | |
625 | fl->fl_start = 0; | |
626 | fl->fl_end = OFFSET_MAX; | |
e8d6c554 DH |
627 | } |
628 | ||
0fafdc9f | 629 | ret = 0; |
e8d6c554 | 630 | error: |
e8d6c554 DH |
631 | _leave(" = %d [%hd]", ret, fl->fl_type); |
632 | return ret; | |
633 | } | |
634 | ||
635 | /* | |
636 | * manage POSIX locks on a file | |
637 | */ | |
638 | int afs_lock(struct file *file, int cmd, struct file_lock *fl) | |
639 | { | |
0fafdc9f | 640 | struct afs_vnode *vnode = AFS_FS_I(locks_inode(file)); |
e8d6c554 DH |
641 | |
642 | _enter("{%x:%u},%d,{t=%x,fl=%x,r=%Ld:%Ld}", | |
643 | vnode->fid.vid, vnode->fid.vnode, cmd, | |
644 | fl->fl_type, fl->fl_flags, | |
645 | (long long) fl->fl_start, (long long) fl->fl_end); | |
646 | ||
647 | /* AFS doesn't support mandatory locks */ | |
fc5846e5 | 648 | if (__mandatory_lock(&vnode->vfs_inode) && fl->fl_type != F_UNLCK) |
e8d6c554 DH |
649 | return -ENOLCK; |
650 | ||
651 | if (IS_GETLK(cmd)) | |
652 | return afs_do_getlk(file, fl); | |
653 | if (fl->fl_type == F_UNLCK) | |
654 | return afs_do_unlk(file, fl); | |
655 | return afs_do_setlk(file, fl); | |
656 | } | |
657 | ||
658 | /* | |
659 | * manage FLOCK locks on a file | |
660 | */ | |
661 | int afs_flock(struct file *file, int cmd, struct file_lock *fl) | |
662 | { | |
0fafdc9f | 663 | struct afs_vnode *vnode = AFS_FS_I(locks_inode(file)); |
e8d6c554 DH |
664 | |
665 | _enter("{%x:%u},%d,{t=%x,fl=%x}", | |
666 | vnode->fid.vid, vnode->fid.vnode, cmd, | |
667 | fl->fl_type, fl->fl_flags); | |
668 | ||
669 | /* | |
670 | * No BSD flocks over NFS allowed. | |
671 | * Note: we could try to fake a POSIX lock request here by | |
672 | * using ((u32) filp | 0x80000000) or some such as the pid. | |
673 | * Not sure whether that would be unique, though, or whether | |
674 | * that would break in other places. | |
675 | */ | |
676 | if (!(fl->fl_flags & FL_FLOCK)) | |
677 | return -ENOLCK; | |
678 | ||
679 | /* we're simulating flock() locks using posix locks on the server */ | |
e8d6c554 DH |
680 | if (fl->fl_type == F_UNLCK) |
681 | return afs_do_unlk(file, fl); | |
682 | return afs_do_setlk(file, fl); | |
683 | } | |
684 | ||
685 | /* | |
686 | * the POSIX lock management core VFS code copies the lock record and adds the | |
687 | * copy into its own list, so we need to add that copy to the vnode's lock | |
688 | * queue in the same place as the original (which will be deleted shortly | |
689 | * after) | |
690 | */ | |
691 | static void afs_fl_copy_lock(struct file_lock *new, struct file_lock *fl) | |
692 | { | |
0fafdc9f DH |
693 | struct afs_vnode *vnode = AFS_FS_I(locks_inode(fl->fl_file)); |
694 | ||
e8d6c554 DH |
695 | _enter(""); |
696 | ||
0fafdc9f | 697 | spin_lock(&vnode->lock); |
e8d6c554 | 698 | list_add(&new->fl_u.afs.link, &fl->fl_u.afs.link); |
0fafdc9f | 699 | spin_unlock(&vnode->lock); |
e8d6c554 DH |
700 | } |
701 | ||
702 | /* | |
703 | * need to remove this lock from the vnode queue when it's removed from the | |
704 | * VFS's list | |
705 | */ | |
706 | static void afs_fl_release_private(struct file_lock *fl) | |
707 | { | |
0fafdc9f DH |
708 | struct afs_vnode *vnode = AFS_FS_I(locks_inode(fl->fl_file)); |
709 | ||
e8d6c554 DH |
710 | _enter(""); |
711 | ||
0fafdc9f DH |
712 | spin_lock(&vnode->lock); |
713 | afs_dequeue_lock(vnode, fl); | |
714 | _debug("state %u for %p", vnode->lock_state, vnode); | |
715 | spin_unlock(&vnode->lock); | |
e8d6c554 | 716 | } |