1 | // SPDX-License-Identifier: GPL-2.0-or-later |
2 | /* AFS file locking support |
3 | * |
4 | * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved. |
5 | * Written by David Howells (dhowells@redhat.com) |
6 | */ |
7 | |
8 | #include "internal.h" |
9 | |
10 | #define AFS_LOCK_GRANTED 0 |
11 | #define AFS_LOCK_PENDING 1 |
12 | #define AFS_LOCK_YOUR_TRY 2 |
13 | |
14 | struct workqueue_struct *afs_lock_manager; |
15 | |
16 | static void afs_next_locker(struct afs_vnode *vnode, int error); |
17 | static void afs_fl_copy_lock(struct file_lock *new, struct file_lock *fl); |
18 | static void afs_fl_release_private(struct file_lock *fl); |
19 | |
20 | static const struct file_lock_operations afs_lock_ops = { |
21 | .fl_copy_lock = afs_fl_copy_lock, |
22 | .fl_release_private = afs_fl_release_private, |
23 | }; |
24 | |
25 | static inline void afs_set_lock_state(struct afs_vnode *vnode, enum afs_lock_state state) |
26 | { |
27 | _debug("STATE %u -> %u" , vnode->lock_state, state); |
28 | vnode->lock_state = state; |
29 | } |
30 | |
31 | static atomic_t afs_file_lock_debug_id; |
32 | |
33 | /* |
34 | * if the callback is broken on this vnode, then the lock may now be available |
35 | */ |
36 | void afs_lock_may_be_available(struct afs_vnode *vnode) |
37 | { |
38 | _enter("{%llx:%llu}" , vnode->fid.vid, vnode->fid.vnode); |
39 | |
40 | spin_lock(lock: &vnode->lock); |
41 | if (vnode->lock_state == AFS_VNODE_LOCK_WAITING_FOR_CB) |
42 | afs_next_locker(vnode, error: 0); |
43 | trace_afs_flock_ev(vnode, NULL, event: afs_flock_callback_break, error: 0); |
44 | spin_unlock(lock: &vnode->lock); |
45 | } |
46 | |
47 | /* |
48 | * the lock will time out in 5 minutes unless we extend it, so schedule |
49 | * extension in a bit less than that time |
50 | */ |
51 | static void afs_schedule_lock_extension(struct afs_vnode *vnode) |
52 | { |
53 | ktime_t expires_at, now, duration; |
54 | u64 duration_j; |
55 | |
56 | expires_at = ktime_add_ms(kt: vnode->locked_at, AFS_LOCKWAIT * 1000 / 2); |
57 | now = ktime_get_real(); |
58 | duration = ktime_sub(expires_at, now); |
59 | if (duration <= 0) |
60 | duration_j = 0; |
61 | else |
62 | duration_j = nsecs_to_jiffies(n: ktime_to_ns(kt: duration)); |
63 | |
64 | queue_delayed_work(wq: afs_lock_manager, dwork: &vnode->lock_work, delay: duration_j); |
65 | } |
66 | |
67 | /* |
68 | * In the case of successful completion of a lock operation, record the time |
69 | * the reply appeared and start the lock extension timer. |
70 | */ |
71 | void afs_lock_op_done(struct afs_call *call) |
72 | { |
73 | struct afs_operation *op = call->op; |
74 | struct afs_vnode *vnode = op->file[0].vnode; |
75 | |
76 | if (call->error == 0) { |
77 | spin_lock(lock: &vnode->lock); |
78 | trace_afs_flock_ev(vnode, NULL, event: afs_flock_timestamp, error: 0); |
79 | vnode->locked_at = call->issue_time; |
80 | afs_schedule_lock_extension(vnode); |
81 | spin_unlock(lock: &vnode->lock); |
82 | } |
83 | } |
84 | |
85 | /* |
86 | * grant one or more locks (readlocks are allowed to jump the queue if the |
87 | * first lock in the queue is itself a readlock) |
88 | * - the caller must hold the vnode lock |
89 | */ |
90 | static void afs_grant_locks(struct afs_vnode *vnode) |
91 | { |
92 | struct file_lock *p, *_p; |
93 | bool exclusive = (vnode->lock_type == AFS_LOCK_WRITE); |
94 | |
95 | list_for_each_entry_safe(p, _p, &vnode->pending_locks, fl_u.afs.link) { |
96 | if (!exclusive && lock_is_write(fl: p)) |
97 | continue; |
98 | |
99 | list_move_tail(list: &p->fl_u.afs.link, head: &vnode->granted_locks); |
100 | p->fl_u.afs.state = AFS_LOCK_GRANTED; |
101 | trace_afs_flock_op(vnode, fl: p, op: afs_flock_op_grant); |
102 | locks_wake_up(fl: p); |
103 | } |
104 | } |
105 | |
106 | /* |
107 | * If an error is specified, reject every pending lock that matches the |
108 | * authentication and type of the lock we failed to get. If there are any |
109 | * remaining lockers, try to wake up one of them to have a go. |
110 | */ |
111 | static void afs_next_locker(struct afs_vnode *vnode, int error) |
112 | { |
113 | struct file_lock *p, *_p, *next = NULL; |
114 | struct key *key = vnode->lock_key; |
115 | unsigned int type = F_RDLCK; |
116 | |
117 | _enter("" ); |
118 | |
119 | if (vnode->lock_type == AFS_LOCK_WRITE) |
120 | type = F_WRLCK; |
121 | |
122 | list_for_each_entry_safe(p, _p, &vnode->pending_locks, fl_u.afs.link) { |
123 | if (error && |
124 | p->c.flc_type == type && |
125 | afs_file_key(file: p->c.flc_file) == key) { |
126 | list_del_init(entry: &p->fl_u.afs.link); |
127 | p->fl_u.afs.state = error; |
128 | locks_wake_up(fl: p); |
129 | } |
130 | |
131 | /* Select the next locker to hand off to. */ |
132 | if (next && (lock_is_write(fl: next) || lock_is_read(fl: p))) |
133 | continue; |
134 | next = p; |
135 | } |
136 | |
137 | vnode->lock_key = NULL; |
138 | key_put(key); |
139 | |
140 | if (next) { |
141 | afs_set_lock_state(vnode, state: AFS_VNODE_LOCK_SETTING); |
142 | next->fl_u.afs.state = AFS_LOCK_YOUR_TRY; |
143 | trace_afs_flock_op(vnode, fl: next, op: afs_flock_op_wake); |
144 | locks_wake_up(fl: next); |
145 | } else { |
146 | afs_set_lock_state(vnode, state: AFS_VNODE_LOCK_NONE); |
147 | trace_afs_flock_ev(vnode, NULL, event: afs_flock_no_lockers, error: 0); |
148 | } |
149 | |
150 | _leave("" ); |
151 | } |
152 | |
153 | /* |
154 | * Kill off all waiters in the the pending lock queue due to the vnode being |
155 | * deleted. |
156 | */ |
157 | static void afs_kill_lockers_enoent(struct afs_vnode *vnode) |
158 | { |
159 | struct file_lock *p; |
160 | |
161 | afs_set_lock_state(vnode, state: AFS_VNODE_LOCK_DELETED); |
162 | |
163 | while (!list_empty(head: &vnode->pending_locks)) { |
164 | p = list_entry(vnode->pending_locks.next, |
165 | struct file_lock, fl_u.afs.link); |
166 | list_del_init(entry: &p->fl_u.afs.link); |
167 | p->fl_u.afs.state = -ENOENT; |
168 | locks_wake_up(fl: p); |
169 | } |
170 | |
171 | key_put(key: vnode->lock_key); |
172 | vnode->lock_key = NULL; |
173 | } |
174 | |
175 | static void afs_lock_success(struct afs_operation *op) |
176 | { |
177 | _enter("op=%08x" , op->debug_id); |
178 | afs_vnode_commit_status(op, &op->file[0]); |
179 | } |
180 | |
181 | static const struct afs_operation_ops afs_set_lock_operation = { |
182 | .issue_afs_rpc = afs_fs_set_lock, |
183 | .issue_yfs_rpc = yfs_fs_set_lock, |
184 | .success = afs_lock_success, |
185 | .aborted = afs_check_for_remote_deletion, |
186 | }; |
187 | |
188 | /* |
189 | * Get a lock on a file |
190 | */ |
191 | static int afs_set_lock(struct afs_vnode *vnode, struct key *key, |
192 | afs_lock_type_t type) |
193 | { |
194 | struct afs_operation *op; |
195 | |
196 | _enter("%s{%llx:%llu.%u},%x,%u" , |
197 | vnode->volume->name, |
198 | vnode->fid.vid, |
199 | vnode->fid.vnode, |
200 | vnode->fid.unique, |
201 | key_serial(key), type); |
202 | |
203 | op = afs_alloc_operation(key, vnode->volume); |
204 | if (IS_ERR(ptr: op)) |
205 | return PTR_ERR(ptr: op); |
206 | |
207 | afs_op_set_vnode(op, n: 0, vnode); |
208 | |
209 | op->lock.type = type; |
210 | op->ops = &afs_set_lock_operation; |
211 | return afs_do_sync_operation(op); |
212 | } |
213 | |
214 | static const struct afs_operation_ops afs_extend_lock_operation = { |
215 | .issue_afs_rpc = afs_fs_extend_lock, |
216 | .issue_yfs_rpc = yfs_fs_extend_lock, |
217 | .success = afs_lock_success, |
218 | }; |
219 | |
220 | /* |
221 | * Extend a lock on a file |
222 | */ |
223 | static int afs_extend_lock(struct afs_vnode *vnode, struct key *key) |
224 | { |
225 | struct afs_operation *op; |
226 | |
227 | _enter("%s{%llx:%llu.%u},%x" , |
228 | vnode->volume->name, |
229 | vnode->fid.vid, |
230 | vnode->fid.vnode, |
231 | vnode->fid.unique, |
232 | key_serial(key)); |
233 | |
234 | op = afs_alloc_operation(key, vnode->volume); |
235 | if (IS_ERR(ptr: op)) |
236 | return PTR_ERR(ptr: op); |
237 | |
238 | afs_op_set_vnode(op, n: 0, vnode); |
239 | |
240 | op->flags |= AFS_OPERATION_UNINTR; |
241 | op->ops = &afs_extend_lock_operation; |
242 | return afs_do_sync_operation(op); |
243 | } |
244 | |
245 | static const struct afs_operation_ops afs_release_lock_operation = { |
246 | .issue_afs_rpc = afs_fs_release_lock, |
247 | .issue_yfs_rpc = yfs_fs_release_lock, |
248 | .success = afs_lock_success, |
249 | }; |
250 | |
251 | /* |
252 | * Release a lock on a file |
253 | */ |
254 | static int afs_release_lock(struct afs_vnode *vnode, struct key *key) |
255 | { |
256 | struct afs_operation *op; |
257 | |
258 | _enter("%s{%llx:%llu.%u},%x" , |
259 | vnode->volume->name, |
260 | vnode->fid.vid, |
261 | vnode->fid.vnode, |
262 | vnode->fid.unique, |
263 | key_serial(key)); |
264 | |
265 | op = afs_alloc_operation(key, vnode->volume); |
266 | if (IS_ERR(ptr: op)) |
267 | return PTR_ERR(ptr: op); |
268 | |
269 | afs_op_set_vnode(op, n: 0, vnode); |
270 | |
271 | op->flags |= AFS_OPERATION_UNINTR; |
272 | op->ops = &afs_release_lock_operation; |
273 | return afs_do_sync_operation(op); |
274 | } |
275 | |
276 | /* |
277 | * do work for a lock, including: |
278 | * - probing for a lock we're waiting on but didn't get immediately |
279 | * - extending a lock that's close to timing out |
280 | */ |
281 | void afs_lock_work(struct work_struct *work) |
282 | { |
283 | struct afs_vnode *vnode = |
284 | container_of(work, struct afs_vnode, lock_work.work); |
285 | struct key *key; |
286 | int ret; |
287 | |
288 | _enter("{%llx:%llu}" , vnode->fid.vid, vnode->fid.vnode); |
289 | |
290 | spin_lock(lock: &vnode->lock); |
291 | |
292 | again: |
293 | _debug("wstate %u for %p" , vnode->lock_state, vnode); |
294 | switch (vnode->lock_state) { |
295 | case AFS_VNODE_LOCK_NEED_UNLOCK: |
296 | afs_set_lock_state(vnode, state: AFS_VNODE_LOCK_UNLOCKING); |
297 | trace_afs_flock_ev(vnode, NULL, event: afs_flock_work_unlocking, error: 0); |
298 | spin_unlock(lock: &vnode->lock); |
299 | |
300 | /* attempt to release the server lock; if it fails, we just |
301 | * wait 5 minutes and it'll expire anyway */ |
302 | ret = afs_release_lock(vnode, key: vnode->lock_key); |
303 | if (ret < 0 && vnode->lock_state != AFS_VNODE_LOCK_DELETED) { |
304 | trace_afs_flock_ev(vnode, NULL, event: afs_flock_release_fail, |
305 | error: ret); |
306 | printk(KERN_WARNING "AFS:" |
307 | " Failed to release lock on {%llx:%llx} error %d\n" , |
308 | vnode->fid.vid, vnode->fid.vnode, ret); |
309 | } |
310 | |
311 | spin_lock(lock: &vnode->lock); |
312 | if (ret == -ENOENT) |
313 | afs_kill_lockers_enoent(vnode); |
314 | else |
315 | afs_next_locker(vnode, error: 0); |
316 | spin_unlock(lock: &vnode->lock); |
317 | return; |
318 | |
319 | /* If we've already got a lock, then it must be time to extend that |
320 | * lock as AFS locks time out after 5 minutes. |
321 | */ |
322 | case AFS_VNODE_LOCK_GRANTED: |
323 | _debug("extend" ); |
324 | |
325 | ASSERT(!list_empty(&vnode->granted_locks)); |
326 | |
327 | key = key_get(key: vnode->lock_key); |
328 | afs_set_lock_state(vnode, state: AFS_VNODE_LOCK_EXTENDING); |
329 | trace_afs_flock_ev(vnode, NULL, event: afs_flock_work_extending, error: 0); |
330 | spin_unlock(lock: &vnode->lock); |
331 | |
332 | ret = afs_extend_lock(vnode, key); /* RPC */ |
333 | key_put(key); |
334 | |
335 | if (ret < 0) { |
336 | trace_afs_flock_ev(vnode, NULL, event: afs_flock_extend_fail, |
337 | error: ret); |
338 | pr_warn("AFS: Failed to extend lock on {%llx:%llx} error %d\n" , |
339 | vnode->fid.vid, vnode->fid.vnode, ret); |
340 | } |
341 | |
342 | spin_lock(lock: &vnode->lock); |
343 | |
344 | if (ret == -ENOENT) { |
345 | afs_kill_lockers_enoent(vnode); |
346 | spin_unlock(lock: &vnode->lock); |
347 | return; |
348 | } |
349 | |
350 | if (vnode->lock_state != AFS_VNODE_LOCK_EXTENDING) |
351 | goto again; |
352 | afs_set_lock_state(vnode, state: AFS_VNODE_LOCK_GRANTED); |
353 | |
354 | if (ret != 0) |
355 | queue_delayed_work(wq: afs_lock_manager, dwork: &vnode->lock_work, |
356 | HZ * 10); |
357 | spin_unlock(lock: &vnode->lock); |
358 | _leave(" [ext]" ); |
359 | return; |
360 | |
361 | /* If we're waiting for a callback to indicate lock release, we can't |
362 | * actually rely on this, so need to recheck at regular intervals. The |
363 | * problem is that the server might not notify us if the lock just |
364 | * expires (say because a client died) rather than being explicitly |
365 | * released. |
366 | */ |
367 | case AFS_VNODE_LOCK_WAITING_FOR_CB: |
368 | _debug("retry" ); |
369 | afs_next_locker(vnode, error: 0); |
370 | spin_unlock(lock: &vnode->lock); |
371 | return; |
372 | |
373 | case AFS_VNODE_LOCK_DELETED: |
374 | afs_kill_lockers_enoent(vnode); |
375 | spin_unlock(lock: &vnode->lock); |
376 | return; |
377 | |
378 | default: |
379 | /* Looks like a lock request was withdrawn. */ |
380 | spin_unlock(lock: &vnode->lock); |
381 | _leave(" [no]" ); |
382 | return; |
383 | } |
384 | } |
385 | |
386 | /* |
387 | * pass responsibility for the unlocking of a vnode on the server to the |
388 | * manager thread, lest a pending signal in the calling thread interrupt |
389 | * AF_RXRPC |
390 | * - the caller must hold the vnode lock |
391 | */ |
392 | static void afs_defer_unlock(struct afs_vnode *vnode) |
393 | { |
394 | _enter("%u" , vnode->lock_state); |
395 | |
396 | if (list_empty(head: &vnode->granted_locks) && |
397 | (vnode->lock_state == AFS_VNODE_LOCK_GRANTED || |
398 | vnode->lock_state == AFS_VNODE_LOCK_EXTENDING)) { |
399 | cancel_delayed_work(dwork: &vnode->lock_work); |
400 | |
401 | afs_set_lock_state(vnode, state: AFS_VNODE_LOCK_NEED_UNLOCK); |
402 | trace_afs_flock_ev(vnode, NULL, event: afs_flock_defer_unlock, error: 0); |
403 | queue_delayed_work(wq: afs_lock_manager, dwork: &vnode->lock_work, delay: 0); |
404 | } |
405 | } |
406 | |
407 | /* |
408 | * Check that our view of the file metadata is up to date and check to see |
409 | * whether we think that we have a locking permit. |
410 | */ |
411 | static int afs_do_setlk_check(struct afs_vnode *vnode, struct key *key, |
412 | enum afs_flock_mode mode, afs_lock_type_t type) |
413 | { |
414 | afs_access_t access; |
415 | int ret; |
416 | |
417 | /* Make sure we've got a callback on this file and that our view of the |
418 | * data version is up to date. |
419 | */ |
420 | ret = afs_validate(vnode, key); |
421 | if (ret < 0) |
422 | return ret; |
423 | |
424 | /* Check the permission set to see if we're actually going to be |
425 | * allowed to get a lock on this file. |
426 | */ |
427 | ret = afs_check_permit(vnode, key, &access); |
428 | if (ret < 0) |
429 | return ret; |
430 | |
431 | /* At a rough estimation, you need LOCK, WRITE or INSERT perm to |
432 | * read-lock a file and WRITE or INSERT perm to write-lock a file. |
433 | * |
434 | * We can't rely on the server to do this for us since if we want to |
435 | * share a read lock that we already have, we won't go the server. |
436 | */ |
437 | if (type == AFS_LOCK_READ) { |
438 | if (!(access & (AFS_ACE_INSERT | AFS_ACE_WRITE | AFS_ACE_LOCK))) |
439 | return -EACCES; |
440 | } else { |
441 | if (!(access & (AFS_ACE_INSERT | AFS_ACE_WRITE))) |
442 | return -EACCES; |
443 | } |
444 | |
445 | return 0; |
446 | } |
447 | |
448 | /* |
449 | * request a lock on a file on the server |
450 | */ |
451 | static int afs_do_setlk(struct file *file, struct file_lock *fl) |
452 | { |
453 | struct inode *inode = file_inode(f: file); |
454 | struct afs_vnode *vnode = AFS_FS_I(inode); |
455 | enum afs_flock_mode mode = AFS_FS_S(sb: inode->i_sb)->flock_mode; |
456 | afs_lock_type_t type; |
457 | struct key *key = afs_file_key(file); |
458 | bool partial, no_server_lock = false; |
459 | int ret; |
460 | |
461 | if (mode == afs_flock_mode_unset) |
462 | mode = afs_flock_mode_openafs; |
463 | |
464 | _enter("{%llx:%llu},%llu-%llu,%u,%u" , |
465 | vnode->fid.vid, vnode->fid.vnode, |
466 | fl->fl_start, fl->fl_end, fl->c.flc_type, mode); |
467 | |
468 | fl->fl_ops = &afs_lock_ops; |
469 | INIT_LIST_HEAD(list: &fl->fl_u.afs.link); |
470 | fl->fl_u.afs.state = AFS_LOCK_PENDING; |
471 | |
472 | partial = (fl->fl_start != 0 || fl->fl_end != OFFSET_MAX); |
473 | type = lock_is_read(fl) ? AFS_LOCK_READ : AFS_LOCK_WRITE; |
474 | if (mode == afs_flock_mode_write && partial) |
475 | type = AFS_LOCK_WRITE; |
476 | |
477 | ret = afs_do_setlk_check(vnode, key, mode, type); |
478 | if (ret < 0) |
479 | return ret; |
480 | |
481 | trace_afs_flock_op(vnode, fl, op: afs_flock_op_set_lock); |
482 | |
483 | /* AFS3 protocol only supports full-file locks and doesn't provide any |
484 | * method of upgrade/downgrade, so we need to emulate for partial-file |
485 | * locks. |
486 | * |
487 | * The OpenAFS client only gets a server lock for a full-file lock and |
488 | * keeps partial-file locks local. Allow this behaviour to be emulated |
489 | * (as the default). |
490 | */ |
491 | if (mode == afs_flock_mode_local || |
492 | (partial && mode == afs_flock_mode_openafs)) { |
493 | no_server_lock = true; |
494 | goto skip_server_lock; |
495 | } |
496 | |
497 | spin_lock(lock: &vnode->lock); |
498 | list_add_tail(new: &fl->fl_u.afs.link, head: &vnode->pending_locks); |
499 | |
500 | ret = -ENOENT; |
501 | if (vnode->lock_state == AFS_VNODE_LOCK_DELETED) |
502 | goto error_unlock; |
503 | |
504 | /* If we've already got a lock on the server then try to move to having |
505 | * the VFS grant the requested lock. Note that this means that other |
506 | * clients may get starved out. |
507 | */ |
508 | _debug("try %u" , vnode->lock_state); |
509 | if (vnode->lock_state == AFS_VNODE_LOCK_GRANTED) { |
510 | if (type == AFS_LOCK_READ) { |
511 | _debug("instant readlock" ); |
512 | list_move_tail(list: &fl->fl_u.afs.link, head: &vnode->granted_locks); |
513 | fl->fl_u.afs.state = AFS_LOCK_GRANTED; |
514 | goto vnode_is_locked_u; |
515 | } |
516 | |
517 | if (vnode->lock_type == AFS_LOCK_WRITE) { |
518 | _debug("instant writelock" ); |
519 | list_move_tail(list: &fl->fl_u.afs.link, head: &vnode->granted_locks); |
520 | fl->fl_u.afs.state = AFS_LOCK_GRANTED; |
521 | goto vnode_is_locked_u; |
522 | } |
523 | } |
524 | |
525 | if (vnode->lock_state == AFS_VNODE_LOCK_NONE && |
526 | !(fl->c.flc_flags & FL_SLEEP)) { |
527 | ret = -EAGAIN; |
528 | if (type == AFS_LOCK_READ) { |
529 | if (vnode->status.lock_count == -1) |
530 | goto lock_is_contended; /* Write locked */ |
531 | } else { |
532 | if (vnode->status.lock_count != 0) |
533 | goto lock_is_contended; /* Locked */ |
534 | } |
535 | } |
536 | |
537 | if (vnode->lock_state != AFS_VNODE_LOCK_NONE) |
538 | goto need_to_wait; |
539 | |
540 | try_to_lock: |
541 | /* We don't have a lock on this vnode and we aren't currently waiting |
542 | * for one either, so ask the server for a lock. |
543 | * |
544 | * Note that we need to be careful if we get interrupted by a signal |
545 | * after dispatching the request as we may still get the lock, even |
546 | * though we don't wait for the reply (it's not too bad a problem - the |
547 | * lock will expire in 5 mins anyway). |
548 | */ |
549 | trace_afs_flock_ev(vnode, fl, event: afs_flock_try_to_lock, error: 0); |
550 | vnode->lock_key = key_get(key); |
551 | vnode->lock_type = type; |
552 | afs_set_lock_state(vnode, state: AFS_VNODE_LOCK_SETTING); |
553 | spin_unlock(lock: &vnode->lock); |
554 | |
555 | ret = afs_set_lock(vnode, key, type); /* RPC */ |
556 | |
557 | spin_lock(lock: &vnode->lock); |
558 | switch (ret) { |
559 | case -EKEYREJECTED: |
560 | case -EKEYEXPIRED: |
561 | case -EKEYREVOKED: |
562 | case -EPERM: |
563 | case -EACCES: |
564 | fl->fl_u.afs.state = ret; |
565 | trace_afs_flock_ev(vnode, fl, event: afs_flock_fail_perm, error: ret); |
566 | list_del_init(entry: &fl->fl_u.afs.link); |
567 | afs_next_locker(vnode, error: ret); |
568 | goto error_unlock; |
569 | |
570 | case -ENOENT: |
571 | fl->fl_u.afs.state = ret; |
572 | trace_afs_flock_ev(vnode, fl, event: afs_flock_fail_other, error: ret); |
573 | list_del_init(entry: &fl->fl_u.afs.link); |
574 | afs_kill_lockers_enoent(vnode); |
575 | goto error_unlock; |
576 | |
577 | default: |
578 | fl->fl_u.afs.state = ret; |
579 | trace_afs_flock_ev(vnode, fl, event: afs_flock_fail_other, error: ret); |
580 | list_del_init(entry: &fl->fl_u.afs.link); |
581 | afs_next_locker(vnode, error: 0); |
582 | goto error_unlock; |
583 | |
584 | case -EWOULDBLOCK: |
585 | /* The server doesn't have a lock-waiting queue, so the client |
586 | * will have to retry. The server will break the outstanding |
587 | * callbacks on a file when a lock is released. |
588 | */ |
589 | ASSERT(list_empty(&vnode->granted_locks)); |
590 | ASSERTCMP(vnode->pending_locks.next, ==, &fl->fl_u.afs.link); |
591 | goto lock_is_contended; |
592 | |
593 | case 0: |
594 | afs_set_lock_state(vnode, state: AFS_VNODE_LOCK_GRANTED); |
595 | trace_afs_flock_ev(vnode, fl, event: afs_flock_acquired, error: type); |
596 | afs_grant_locks(vnode); |
597 | goto vnode_is_locked_u; |
598 | } |
599 | |
600 | vnode_is_locked_u: |
601 | spin_unlock(lock: &vnode->lock); |
602 | vnode_is_locked: |
603 | /* the lock has been granted by the server... */ |
604 | ASSERTCMP(fl->fl_u.afs.state, ==, AFS_LOCK_GRANTED); |
605 | |
606 | skip_server_lock: |
607 | /* ... but the VFS still needs to distribute access on this client. */ |
608 | trace_afs_flock_ev(vnode, fl, event: afs_flock_vfs_locking, error: 0); |
609 | ret = locks_lock_file_wait(filp: file, fl); |
610 | trace_afs_flock_ev(vnode, fl, event: afs_flock_vfs_lock, error: ret); |
611 | if (ret < 0) |
612 | goto vfs_rejected_lock; |
613 | |
614 | /* Again, make sure we've got a callback on this file and, again, make |
615 | * sure that our view of the data version is up to date (we ignore |
616 | * errors incurred here and deal with the consequences elsewhere). |
617 | */ |
618 | afs_validate(vnode, key); |
619 | _leave(" = 0" ); |
620 | return 0; |
621 | |
622 | lock_is_contended: |
623 | if (!(fl->c.flc_flags & FL_SLEEP)) { |
624 | list_del_init(entry: &fl->fl_u.afs.link); |
625 | afs_next_locker(vnode, error: 0); |
626 | ret = -EAGAIN; |
627 | goto error_unlock; |
628 | } |
629 | |
630 | afs_set_lock_state(vnode, state: AFS_VNODE_LOCK_WAITING_FOR_CB); |
631 | trace_afs_flock_ev(vnode, fl, event: afs_flock_would_block, error: ret); |
632 | queue_delayed_work(wq: afs_lock_manager, dwork: &vnode->lock_work, HZ * 5); |
633 | |
634 | need_to_wait: |
635 | /* We're going to have to wait. Either this client doesn't have a lock |
636 | * on the server yet and we need to wait for a callback to occur, or |
637 | * the client does have a lock on the server, but it's shared and we |
638 | * need an exclusive lock. |
639 | */ |
640 | spin_unlock(lock: &vnode->lock); |
641 | |
642 | trace_afs_flock_ev(vnode, fl, event: afs_flock_waiting, error: 0); |
643 | ret = wait_event_interruptible(fl->c.flc_wait, |
644 | fl->fl_u.afs.state != AFS_LOCK_PENDING); |
645 | trace_afs_flock_ev(vnode, fl, event: afs_flock_waited, error: ret); |
646 | |
647 | if (fl->fl_u.afs.state >= 0 && fl->fl_u.afs.state != AFS_LOCK_GRANTED) { |
648 | spin_lock(lock: &vnode->lock); |
649 | |
650 | switch (fl->fl_u.afs.state) { |
651 | case AFS_LOCK_YOUR_TRY: |
652 | fl->fl_u.afs.state = AFS_LOCK_PENDING; |
653 | goto try_to_lock; |
654 | case AFS_LOCK_PENDING: |
655 | if (ret > 0) { |
656 | /* We need to retry the lock. We may not be |
657 | * notified by the server if it just expired |
658 | * rather than being released. |
659 | */ |
660 | ASSERTCMP(vnode->lock_state, ==, AFS_VNODE_LOCK_WAITING_FOR_CB); |
661 | afs_set_lock_state(vnode, state: AFS_VNODE_LOCK_SETTING); |
662 | fl->fl_u.afs.state = AFS_LOCK_PENDING; |
663 | goto try_to_lock; |
664 | } |
665 | goto error_unlock; |
666 | case AFS_LOCK_GRANTED: |
667 | default: |
668 | break; |
669 | } |
670 | |
671 | spin_unlock(lock: &vnode->lock); |
672 | } |
673 | |
674 | if (fl->fl_u.afs.state == AFS_LOCK_GRANTED) |
675 | goto vnode_is_locked; |
676 | ret = fl->fl_u.afs.state; |
677 | goto error; |
678 | |
679 | vfs_rejected_lock: |
680 | /* The VFS rejected the lock we just obtained, so we have to discard |
681 | * what we just got. We defer this to the lock manager work item to |
682 | * deal with. |
683 | */ |
684 | _debug("vfs refused %d" , ret); |
685 | if (no_server_lock) |
686 | goto error; |
687 | spin_lock(lock: &vnode->lock); |
688 | list_del_init(entry: &fl->fl_u.afs.link); |
689 | afs_defer_unlock(vnode); |
690 | |
691 | error_unlock: |
692 | spin_unlock(lock: &vnode->lock); |
693 | error: |
694 | _leave(" = %d" , ret); |
695 | return ret; |
696 | } |
697 | |
698 | /* |
699 | * unlock on a file on the server |
700 | */ |
701 | static int afs_do_unlk(struct file *file, struct file_lock *fl) |
702 | { |
703 | struct afs_vnode *vnode = AFS_FS_I(inode: file_inode(f: file)); |
704 | int ret; |
705 | |
706 | _enter("{%llx:%llu},%u" , vnode->fid.vid, vnode->fid.vnode, |
707 | fl->c.flc_type); |
708 | |
709 | trace_afs_flock_op(vnode, fl, op: afs_flock_op_unlock); |
710 | |
711 | /* Flush all pending writes before doing anything with locks. */ |
712 | vfs_fsync(file, datasync: 0); |
713 | |
714 | ret = locks_lock_file_wait(filp: file, fl); |
715 | _leave(" = %d [%u]" , ret, vnode->lock_state); |
716 | return ret; |
717 | } |
718 | |
719 | /* |
720 | * return information about a lock we currently hold, if indeed we hold one |
721 | */ |
722 | static int afs_do_getlk(struct file *file, struct file_lock *fl) |
723 | { |
724 | struct afs_vnode *vnode = AFS_FS_I(inode: file_inode(f: file)); |
725 | struct key *key = afs_file_key(file); |
726 | int ret, lock_count; |
727 | |
728 | _enter("" ); |
729 | |
730 | if (vnode->lock_state == AFS_VNODE_LOCK_DELETED) |
731 | return -ENOENT; |
732 | |
733 | fl->c.flc_type = F_UNLCK; |
734 | |
735 | /* check local lock records first */ |
736 | posix_test_lock(file, fl); |
737 | if (lock_is_unlock(fl)) { |
738 | /* no local locks; consult the server */ |
739 | ret = afs_fetch_status(vnode, key, false, NULL); |
740 | if (ret < 0) |
741 | goto error; |
742 | |
743 | lock_count = READ_ONCE(vnode->status.lock_count); |
744 | if (lock_count != 0) { |
745 | if (lock_count > 0) |
746 | fl->c.flc_type = F_RDLCK; |
747 | else |
748 | fl->c.flc_type = F_WRLCK; |
749 | fl->fl_start = 0; |
750 | fl->fl_end = OFFSET_MAX; |
751 | fl->c.flc_pid = 0; |
752 | } |
753 | } |
754 | |
755 | ret = 0; |
756 | error: |
757 | _leave(" = %d [%hd]" , ret, fl->c.flc_type); |
758 | return ret; |
759 | } |
760 | |
761 | /* |
762 | * manage POSIX locks on a file |
763 | */ |
764 | int afs_lock(struct file *file, int cmd, struct file_lock *fl) |
765 | { |
766 | struct afs_vnode *vnode = AFS_FS_I(inode: file_inode(f: file)); |
767 | enum afs_flock_operation op; |
768 | int ret; |
769 | |
770 | _enter("{%llx:%llu},%d,{t=%x,fl=%x,r=%Ld:%Ld}" , |
771 | vnode->fid.vid, vnode->fid.vnode, cmd, |
772 | fl->c.flc_type, fl->c.flc_flags, |
773 | (long long) fl->fl_start, (long long) fl->fl_end); |
774 | |
775 | if (IS_GETLK(cmd)) |
776 | return afs_do_getlk(file, fl); |
777 | |
778 | fl->fl_u.afs.debug_id = atomic_inc_return(v: &afs_file_lock_debug_id); |
779 | trace_afs_flock_op(vnode, fl, op: afs_flock_op_lock); |
780 | |
781 | if (lock_is_unlock(fl)) |
782 | ret = afs_do_unlk(file, fl); |
783 | else |
784 | ret = afs_do_setlk(file, fl); |
785 | |
786 | switch (ret) { |
787 | case 0: op = afs_flock_op_return_ok; break; |
788 | case -EAGAIN: op = afs_flock_op_return_eagain; break; |
789 | case -EDEADLK: op = afs_flock_op_return_edeadlk; break; |
790 | default: op = afs_flock_op_return_error; break; |
791 | } |
792 | trace_afs_flock_op(vnode, fl, op); |
793 | return ret; |
794 | } |
795 | |
796 | /* |
797 | * manage FLOCK locks on a file |
798 | */ |
799 | int afs_flock(struct file *file, int cmd, struct file_lock *fl) |
800 | { |
801 | struct afs_vnode *vnode = AFS_FS_I(inode: file_inode(f: file)); |
802 | enum afs_flock_operation op; |
803 | int ret; |
804 | |
805 | _enter("{%llx:%llu},%d,{t=%x,fl=%x}" , |
806 | vnode->fid.vid, vnode->fid.vnode, cmd, |
807 | fl->c.flc_type, fl->c.flc_flags); |
808 | |
809 | /* |
810 | * No BSD flocks over NFS allowed. |
811 | * Note: we could try to fake a POSIX lock request here by |
812 | * using ((u32) filp | 0x80000000) or some such as the pid. |
813 | * Not sure whether that would be unique, though, or whether |
814 | * that would break in other places. |
815 | */ |
816 | if (!(fl->c.flc_flags & FL_FLOCK)) |
817 | return -ENOLCK; |
818 | |
819 | fl->fl_u.afs.debug_id = atomic_inc_return(v: &afs_file_lock_debug_id); |
820 | trace_afs_flock_op(vnode, fl, op: afs_flock_op_flock); |
821 | |
822 | /* we're simulating flock() locks using posix locks on the server */ |
823 | if (lock_is_unlock(fl)) |
824 | ret = afs_do_unlk(file, fl); |
825 | else |
826 | ret = afs_do_setlk(file, fl); |
827 | |
828 | switch (ret) { |
829 | case 0: op = afs_flock_op_return_ok; break; |
830 | case -EAGAIN: op = afs_flock_op_return_eagain; break; |
831 | case -EDEADLK: op = afs_flock_op_return_edeadlk; break; |
832 | default: op = afs_flock_op_return_error; break; |
833 | } |
834 | trace_afs_flock_op(vnode, fl, op); |
835 | return ret; |
836 | } |
837 | |
838 | /* |
839 | * the POSIX lock management core VFS code copies the lock record and adds the |
840 | * copy into its own list, so we need to add that copy to the vnode's lock |
841 | * queue in the same place as the original (which will be deleted shortly |
842 | * after) |
843 | */ |
844 | static void afs_fl_copy_lock(struct file_lock *new, struct file_lock *fl) |
845 | { |
846 | struct afs_vnode *vnode = AFS_FS_I(inode: file_inode(f: fl->c.flc_file)); |
847 | |
848 | _enter("" ); |
849 | |
850 | new->fl_u.afs.debug_id = atomic_inc_return(v: &afs_file_lock_debug_id); |
851 | |
852 | spin_lock(lock: &vnode->lock); |
853 | trace_afs_flock_op(vnode, fl: new, op: afs_flock_op_copy_lock); |
854 | list_add(new: &new->fl_u.afs.link, head: &fl->fl_u.afs.link); |
855 | spin_unlock(lock: &vnode->lock); |
856 | } |
857 | |
858 | /* |
859 | * need to remove this lock from the vnode queue when it's removed from the |
860 | * VFS's list |
861 | */ |
862 | static void afs_fl_release_private(struct file_lock *fl) |
863 | { |
864 | struct afs_vnode *vnode = AFS_FS_I(inode: file_inode(f: fl->c.flc_file)); |
865 | |
866 | _enter("" ); |
867 | |
868 | spin_lock(lock: &vnode->lock); |
869 | |
870 | trace_afs_flock_op(vnode, fl, op: afs_flock_op_release_lock); |
871 | list_del_init(entry: &fl->fl_u.afs.link); |
872 | if (list_empty(head: &vnode->granted_locks)) |
873 | afs_defer_unlock(vnode); |
874 | |
875 | _debug("state %u for %p" , vnode->lock_state, vnode); |
876 | spin_unlock(lock: &vnode->lock); |
877 | } |
878 | |