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2874c5fd | 1 | // SPDX-License-Identifier: GPL-2.0-or-later |
e8d6c554 DH |
2 | /* AFS file locking support |
3 | * | |
4 | * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved. | |
5 | * Written by David Howells (dhowells@redhat.com) | |
e8d6c554 DH |
6 | */ |
7 | ||
e8d6c554 DH |
8 | #include "internal.h" |
9 | ||
10 | #define AFS_LOCK_GRANTED 0 | |
11 | #define AFS_LOCK_PENDING 1 | |
4be5975a | 12 | #define AFS_LOCK_YOUR_TRY 2 |
e8d6c554 | 13 | |
f044c884 DH |
14 | struct workqueue_struct *afs_lock_manager; |
15 | ||
4be5975a | 16 | static void afs_next_locker(struct afs_vnode *vnode, int error); |
e8d6c554 DH |
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 | ||
6aed6285 | 20 | static const struct file_lock_operations afs_lock_ops = { |
e8d6c554 DH |
21 | .fl_copy_lock = afs_fl_copy_lock, |
22 | .fl_release_private = afs_fl_release_private, | |
23 | }; | |
24 | ||
4be5975a DH |
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 | ||
d4696601 DH |
31 | static atomic_t afs_file_lock_debug_id; |
32 | ||
e8d6c554 DH |
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 | { | |
3b6492df | 38 | _enter("{%llx:%llu}", vnode->fid.vid, vnode->fid.vnode); |
e8d6c554 | 39 | |
4be5975a DH |
40 | spin_lock(&vnode->lock); |
41 | if (vnode->lock_state == AFS_VNODE_LOCK_WAITING_FOR_CB) | |
42 | afs_next_locker(vnode, 0); | |
d4696601 | 43 | trace_afs_flock_ev(vnode, NULL, afs_flock_callback_break, 0); |
4be5975a | 44 | spin_unlock(&vnode->lock); |
e8d6c554 DH |
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 | { | |
a690f60a DH |
53 | ktime_t expires_at, now, duration; |
54 | u64 duration_j; | |
55 | ||
56 | expires_at = ktime_add_ms(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(ktime_to_ns(duration)); | |
63 | ||
64 | queue_delayed_work(afs_lock_manager, &vnode->lock_work, 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 | { | |
e49c7b2f | 73 | struct afs_operation *op = call->op; |
5749ce92 | 74 | struct afs_vnode *vnode = op->file[0].vnode; |
a690f60a DH |
75 | |
76 | if (call->error == 0) { | |
77 | spin_lock(&vnode->lock); | |
d4696601 | 78 | trace_afs_flock_ev(vnode, NULL, afs_flock_timestamp, 0); |
a690f60a DH |
79 | vnode->locked_at = call->reply_time; |
80 | afs_schedule_lock_extension(vnode); | |
81 | spin_unlock(&vnode->lock); | |
82 | } | |
e8d6c554 DH |
83 | } |
84 | ||
ff8e210a DH |
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 | */ | |
4be5975a | 90 | static void afs_grant_locks(struct afs_vnode *vnode) |
ff8e210a DH |
91 | { |
92 | struct file_lock *p, *_p; | |
4be5975a | 93 | bool exclusive = (vnode->lock_type == AFS_LOCK_WRITE); |
ff8e210a | 94 | |
4be5975a DH |
95 | list_for_each_entry_safe(p, _p, &vnode->pending_locks, fl_u.afs.link) { |
96 | if (!exclusive && p->fl_type == F_WRLCK) | |
97 | continue; | |
98 | ||
99 | list_move_tail(&p->fl_u.afs.link, &vnode->granted_locks); | |
100 | p->fl_u.afs.state = AFS_LOCK_GRANTED; | |
d4696601 | 101 | trace_afs_flock_op(vnode, p, afs_flock_op_grant); |
4be5975a DH |
102 | wake_up(&p->fl_wait); |
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 fl_type = F_RDLCK; | |
116 | ||
117 | _enter(""); | |
118 | ||
119 | if (vnode->lock_type == AFS_LOCK_WRITE) | |
120 | fl_type = F_WRLCK; | |
121 | ||
122 | list_for_each_entry_safe(p, _p, &vnode->pending_locks, fl_u.afs.link) { | |
123 | if (error && | |
124 | p->fl_type == fl_type && | |
125 | afs_file_key(p->fl_file) == key) { | |
126 | list_del_init(&p->fl_u.afs.link); | |
127 | p->fl_u.afs.state = error; | |
128 | wake_up(&p->fl_wait); | |
ff8e210a | 129 | } |
4be5975a DH |
130 | |
131 | /* Select the next locker to hand off to. */ | |
132 | if (next && | |
133 | (next->fl_type == F_WRLCK || p->fl_type == F_RDLCK)) | |
134 | continue; | |
135 | next = p; | |
ff8e210a | 136 | } |
4be5975a DH |
137 | |
138 | vnode->lock_key = NULL; | |
139 | key_put(key); | |
140 | ||
141 | if (next) { | |
142 | afs_set_lock_state(vnode, AFS_VNODE_LOCK_SETTING); | |
143 | next->fl_u.afs.state = AFS_LOCK_YOUR_TRY; | |
d4696601 | 144 | trace_afs_flock_op(vnode, next, afs_flock_op_wake); |
4be5975a DH |
145 | wake_up(&next->fl_wait); |
146 | } else { | |
147 | afs_set_lock_state(vnode, AFS_VNODE_LOCK_NONE); | |
d4696601 | 148 | trace_afs_flock_ev(vnode, NULL, afs_flock_no_lockers, 0); |
4be5975a DH |
149 | } |
150 | ||
151 | _leave(""); | |
ff8e210a DH |
152 | } |
153 | ||
cdfb26b4 DH |
154 | /* |
155 | * Kill off all waiters in the the pending lock queue due to the vnode being | |
156 | * deleted. | |
157 | */ | |
158 | static void afs_kill_lockers_enoent(struct afs_vnode *vnode) | |
159 | { | |
160 | struct file_lock *p; | |
161 | ||
162 | afs_set_lock_state(vnode, AFS_VNODE_LOCK_DELETED); | |
163 | ||
164 | while (!list_empty(&vnode->pending_locks)) { | |
165 | p = list_entry(vnode->pending_locks.next, | |
166 | struct file_lock, fl_u.afs.link); | |
167 | list_del_init(&p->fl_u.afs.link); | |
168 | p->fl_u.afs.state = -ENOENT; | |
169 | wake_up(&p->fl_wait); | |
170 | } | |
171 | ||
172 | key_put(vnode->lock_key); | |
173 | vnode->lock_key = NULL; | |
ff8e210a DH |
174 | } |
175 | ||
e49c7b2f DH |
176 | static void afs_lock_success(struct afs_operation *op) |
177 | { | |
e49c7b2f | 178 | _enter("op=%08x", op->debug_id); |
e49c7b2f DH |
179 | afs_vnode_commit_status(op, &op->file[0]); |
180 | } | |
181 | ||
182 | static const struct afs_operation_ops afs_set_lock_operation = { | |
183 | .issue_afs_rpc = afs_fs_set_lock, | |
184 | .issue_yfs_rpc = yfs_fs_set_lock, | |
185 | .success = afs_lock_success, | |
728279a5 | 186 | .aborted = afs_check_for_remote_deletion, |
e49c7b2f DH |
187 | }; |
188 | ||
d2ddc776 DH |
189 | /* |
190 | * Get a lock on a file | |
191 | */ | |
192 | static int afs_set_lock(struct afs_vnode *vnode, struct key *key, | |
193 | afs_lock_type_t type) | |
194 | { | |
e49c7b2f | 195 | struct afs_operation *op; |
d2ddc776 | 196 | |
3b6492df | 197 | _enter("%s{%llx:%llu.%u},%x,%u", |
d2ddc776 DH |
198 | vnode->volume->name, |
199 | vnode->fid.vid, | |
200 | vnode->fid.vnode, | |
201 | vnode->fid.unique, | |
202 | key_serial(key), type); | |
203 | ||
e49c7b2f DH |
204 | op = afs_alloc_operation(key, vnode->volume); |
205 | if (IS_ERR(op)) | |
206 | return PTR_ERR(op); | |
a58823ac | 207 | |
e49c7b2f | 208 | afs_op_set_vnode(op, 0, vnode); |
d2ddc776 | 209 | |
e49c7b2f DH |
210 | op->lock.type = type; |
211 | op->ops = &afs_set_lock_operation; | |
212 | return afs_do_sync_operation(op); | |
d2ddc776 DH |
213 | } |
214 | ||
e49c7b2f DH |
215 | static const struct afs_operation_ops afs_extend_lock_operation = { |
216 | .issue_afs_rpc = afs_fs_extend_lock, | |
217 | .issue_yfs_rpc = yfs_fs_extend_lock, | |
218 | .success = afs_lock_success, | |
219 | }; | |
220 | ||
d2ddc776 DH |
221 | /* |
222 | * Extend a lock on a file | |
223 | */ | |
224 | static int afs_extend_lock(struct afs_vnode *vnode, struct key *key) | |
225 | { | |
e49c7b2f | 226 | struct afs_operation *op; |
d2ddc776 | 227 | |
3b6492df | 228 | _enter("%s{%llx:%llu.%u},%x", |
d2ddc776 DH |
229 | vnode->volume->name, |
230 | vnode->fid.vid, | |
231 | vnode->fid.vnode, | |
232 | vnode->fid.unique, | |
233 | key_serial(key)); | |
234 | ||
e49c7b2f DH |
235 | op = afs_alloc_operation(key, vnode->volume); |
236 | if (IS_ERR(op)) | |
237 | return PTR_ERR(op); | |
d2ddc776 | 238 | |
e49c7b2f | 239 | afs_op_set_vnode(op, 0, vnode); |
d2ddc776 | 240 | |
e49c7b2f DH |
241 | op->flags |= AFS_OPERATION_UNINTR; |
242 | op->ops = &afs_extend_lock_operation; | |
243 | return afs_do_sync_operation(op); | |
d2ddc776 DH |
244 | } |
245 | ||
e49c7b2f DH |
246 | static const struct afs_operation_ops afs_release_lock_operation = { |
247 | .issue_afs_rpc = afs_fs_release_lock, | |
248 | .issue_yfs_rpc = yfs_fs_release_lock, | |
249 | .success = afs_lock_success, | |
250 | }; | |
251 | ||
d2ddc776 DH |
252 | /* |
253 | * Release a lock on a file | |
254 | */ | |
255 | static int afs_release_lock(struct afs_vnode *vnode, struct key *key) | |
256 | { | |
e49c7b2f | 257 | struct afs_operation *op; |
d2ddc776 | 258 | |
3b6492df | 259 | _enter("%s{%llx:%llu.%u},%x", |
d2ddc776 DH |
260 | vnode->volume->name, |
261 | vnode->fid.vid, | |
262 | vnode->fid.vnode, | |
263 | vnode->fid.unique, | |
264 | key_serial(key)); | |
265 | ||
e49c7b2f DH |
266 | op = afs_alloc_operation(key, vnode->volume); |
267 | if (IS_ERR(op)) | |
268 | return PTR_ERR(op); | |
a58823ac | 269 | |
e49c7b2f | 270 | afs_op_set_vnode(op, 0, vnode); |
d2ddc776 | 271 | |
e49c7b2f DH |
272 | op->flags |= AFS_OPERATION_UNINTR; |
273 | op->ops = &afs_release_lock_operation; | |
274 | return afs_do_sync_operation(op); | |
d2ddc776 DH |
275 | } |
276 | ||
e8d6c554 DH |
277 | /* |
278 | * do work for a lock, including: | |
279 | * - probing for a lock we're waiting on but didn't get immediately | |
280 | * - extending a lock that's close to timing out | |
281 | */ | |
282 | void afs_lock_work(struct work_struct *work) | |
283 | { | |
284 | struct afs_vnode *vnode = | |
285 | container_of(work, struct afs_vnode, lock_work.work); | |
e8d6c554 DH |
286 | struct key *key; |
287 | int ret; | |
288 | ||
3b6492df | 289 | _enter("{%llx:%llu}", vnode->fid.vid, vnode->fid.vnode); |
e8d6c554 DH |
290 | |
291 | spin_lock(&vnode->lock); | |
292 | ||
0fafdc9f DH |
293 | again: |
294 | _debug("wstate %u for %p", vnode->lock_state, vnode); | |
295 | switch (vnode->lock_state) { | |
296 | case AFS_VNODE_LOCK_NEED_UNLOCK: | |
4be5975a | 297 | afs_set_lock_state(vnode, AFS_VNODE_LOCK_UNLOCKING); |
d4696601 | 298 | trace_afs_flock_ev(vnode, NULL, afs_flock_work_unlocking, 0); |
e8d6c554 DH |
299 | spin_unlock(&vnode->lock); |
300 | ||
301 | /* attempt to release the server lock; if it fails, we just | |
0fafdc9f DH |
302 | * wait 5 minutes and it'll expire anyway */ |
303 | ret = afs_release_lock(vnode, vnode->lock_key); | |
79ddbfa5 | 304 | if (ret < 0 && vnode->lock_state != AFS_VNODE_LOCK_DELETED) { |
cdfb26b4 DH |
305 | trace_afs_flock_ev(vnode, NULL, afs_flock_release_fail, |
306 | ret); | |
e8d6c554 | 307 | printk(KERN_WARNING "AFS:" |
3b6492df | 308 | " Failed to release lock on {%llx:%llx} error %d\n", |
e8d6c554 | 309 | vnode->fid.vid, vnode->fid.vnode, ret); |
0fafdc9f DH |
310 | } |
311 | ||
e8d6c554 | 312 | spin_lock(&vnode->lock); |
cdfb26b4 DH |
313 | if (ret == -ENOENT) |
314 | afs_kill_lockers_enoent(vnode); | |
315 | else | |
316 | afs_next_locker(vnode, 0); | |
4be5975a DH |
317 | spin_unlock(&vnode->lock); |
318 | return; | |
e8d6c554 | 319 | |
0fafdc9f DH |
320 | /* If we've already got a lock, then it must be time to extend that |
321 | * lock as AFS locks time out after 5 minutes. | |
322 | */ | |
323 | case AFS_VNODE_LOCK_GRANTED: | |
e8d6c554 DH |
324 | _debug("extend"); |
325 | ||
0fafdc9f DH |
326 | ASSERT(!list_empty(&vnode->granted_locks)); |
327 | ||
328 | key = key_get(vnode->lock_key); | |
4be5975a | 329 | afs_set_lock_state(vnode, AFS_VNODE_LOCK_EXTENDING); |
d4696601 | 330 | trace_afs_flock_ev(vnode, NULL, afs_flock_work_extending, 0); |
e8d6c554 DH |
331 | spin_unlock(&vnode->lock); |
332 | ||
0fafdc9f | 333 | ret = afs_extend_lock(vnode, key); /* RPC */ |
e8d6c554 | 334 | key_put(key); |
0fafdc9f | 335 | |
cdfb26b4 DH |
336 | if (ret < 0) { |
337 | trace_afs_flock_ev(vnode, NULL, afs_flock_extend_fail, | |
338 | ret); | |
a4e530ae KW |
339 | pr_warn("AFS: Failed to extend lock on {%llx:%llx} error %d\n", |
340 | vnode->fid.vid, vnode->fid.vnode, ret); | |
cdfb26b4 | 341 | } |
0fafdc9f DH |
342 | |
343 | spin_lock(&vnode->lock); | |
344 | ||
cdfb26b4 DH |
345 | if (ret == -ENOENT) { |
346 | afs_kill_lockers_enoent(vnode); | |
347 | spin_unlock(&vnode->lock); | |
348 | return; | |
349 | } | |
350 | ||
0fafdc9f DH |
351 | if (vnode->lock_state != AFS_VNODE_LOCK_EXTENDING) |
352 | goto again; | |
4be5975a | 353 | afs_set_lock_state(vnode, AFS_VNODE_LOCK_GRANTED); |
0fafdc9f | 354 | |
4be5975a | 355 | if (ret != 0) |
e8d6c554 DH |
356 | queue_delayed_work(afs_lock_manager, &vnode->lock_work, |
357 | HZ * 10); | |
0fafdc9f DH |
358 | spin_unlock(&vnode->lock); |
359 | _leave(" [ext]"); | |
e8d6c554 | 360 | return; |
e8d6c554 | 361 | |
4be5975a DH |
362 | /* If we're waiting for a callback to indicate lock release, we can't |
363 | * actually rely on this, so need to recheck at regular intervals. The | |
364 | * problem is that the server might not notify us if the lock just | |
365 | * expires (say because a client died) rather than being explicitly | |
366 | * released. | |
367 | */ | |
0fafdc9f | 368 | case AFS_VNODE_LOCK_WAITING_FOR_CB: |
4be5975a DH |
369 | _debug("retry"); |
370 | afs_next_locker(vnode, 0); | |
e8d6c554 | 371 | spin_unlock(&vnode->lock); |
4be5975a | 372 | return; |
e8d6c554 | 373 | |
cdfb26b4 DH |
374 | case AFS_VNODE_LOCK_DELETED: |
375 | afs_kill_lockers_enoent(vnode); | |
376 | spin_unlock(&vnode->lock); | |
377 | return; | |
0fafdc9f DH |
378 | |
379 | default: | |
380 | /* Looks like a lock request was withdrawn. */ | |
381 | spin_unlock(&vnode->lock); | |
382 | _leave(" [no]"); | |
e8d6c554 DH |
383 | return; |
384 | } | |
e8d6c554 DH |
385 | } |
386 | ||
387 | /* | |
388 | * pass responsibility for the unlocking of a vnode on the server to the | |
389 | * manager thread, lest a pending signal in the calling thread interrupt | |
390 | * AF_RXRPC | |
391 | * - the caller must hold the vnode lock | |
392 | */ | |
0fafdc9f | 393 | static void afs_defer_unlock(struct afs_vnode *vnode) |
e8d6c554 | 394 | { |
4be5975a | 395 | _enter("%u", vnode->lock_state); |
0fafdc9f | 396 | |
4be5975a DH |
397 | if (list_empty(&vnode->granted_locks) && |
398 | (vnode->lock_state == AFS_VNODE_LOCK_GRANTED || | |
399 | vnode->lock_state == AFS_VNODE_LOCK_EXTENDING)) { | |
0fafdc9f DH |
400 | cancel_delayed_work(&vnode->lock_work); |
401 | ||
4be5975a | 402 | afs_set_lock_state(vnode, AFS_VNODE_LOCK_NEED_UNLOCK); |
d4696601 | 403 | trace_afs_flock_ev(vnode, NULL, afs_flock_defer_unlock, 0); |
4be5975a | 404 | queue_delayed_work(afs_lock_manager, &vnode->lock_work, 0); |
0fafdc9f DH |
405 | } |
406 | } | |
407 | ||
408 | /* | |
409 | * Check that our view of the file metadata is up to date and check to see | |
410 | * whether we think that we have a locking permit. | |
411 | */ | |
412 | static int afs_do_setlk_check(struct afs_vnode *vnode, struct key *key, | |
6c6c1d63 | 413 | enum afs_flock_mode mode, afs_lock_type_t type) |
0fafdc9f DH |
414 | { |
415 | afs_access_t access; | |
416 | int ret; | |
417 | ||
418 | /* Make sure we've got a callback on this file and that our view of the | |
419 | * data version is up to date. | |
420 | */ | |
421 | ret = afs_validate(vnode, key); | |
422 | if (ret < 0) | |
423 | return ret; | |
424 | ||
425 | /* Check the permission set to see if we're actually going to be | |
426 | * allowed to get a lock on this file. | |
427 | */ | |
428 | ret = afs_check_permit(vnode, key, &access); | |
429 | if (ret < 0) | |
430 | return ret; | |
431 | ||
432 | /* At a rough estimation, you need LOCK, WRITE or INSERT perm to | |
433 | * read-lock a file and WRITE or INSERT perm to write-lock a file. | |
434 | * | |
435 | * We can't rely on the server to do this for us since if we want to | |
436 | * share a read lock that we already have, we won't go the server. | |
437 | */ | |
438 | if (type == AFS_LOCK_READ) { | |
439 | if (!(access & (AFS_ACE_INSERT | AFS_ACE_WRITE | AFS_ACE_LOCK))) | |
440 | return -EACCES; | |
0fafdc9f DH |
441 | } else { |
442 | if (!(access & (AFS_ACE_INSERT | AFS_ACE_WRITE))) | |
443 | return -EACCES; | |
0fafdc9f DH |
444 | } |
445 | ||
446 | return 0; | |
447 | } | |
448 | ||
e8d6c554 DH |
449 | /* |
450 | * request a lock on a file on the server | |
451 | */ | |
452 | static int afs_do_setlk(struct file *file, struct file_lock *fl) | |
453 | { | |
0fafdc9f | 454 | struct inode *inode = locks_inode(file); |
1c8c601a | 455 | struct afs_vnode *vnode = AFS_FS_I(inode); |
6c6c1d63 | 456 | enum afs_flock_mode mode = AFS_FS_S(inode->i_sb)->flock_mode; |
e8d6c554 | 457 | afs_lock_type_t type; |
215804a9 | 458 | struct key *key = afs_file_key(file); |
6c6c1d63 | 459 | bool partial, no_server_lock = false; |
e8d6c554 DH |
460 | int ret; |
461 | ||
6c6c1d63 DH |
462 | if (mode == afs_flock_mode_unset) |
463 | mode = afs_flock_mode_openafs; | |
e8d6c554 | 464 | |
6c6c1d63 DH |
465 | _enter("{%llx:%llu},%llu-%llu,%u,%u", |
466 | vnode->fid.vid, vnode->fid.vnode, | |
467 | fl->fl_start, fl->fl_end, fl->fl_type, mode); | |
e8d6c554 | 468 | |
e8d6c554 DH |
469 | fl->fl_ops = &afs_lock_ops; |
470 | INIT_LIST_HEAD(&fl->fl_u.afs.link); | |
471 | fl->fl_u.afs.state = AFS_LOCK_PENDING; | |
472 | ||
6c6c1d63 | 473 | partial = (fl->fl_start != 0 || fl->fl_end != OFFSET_MAX); |
e8d6c554 | 474 | type = (fl->fl_type == F_RDLCK) ? AFS_LOCK_READ : AFS_LOCK_WRITE; |
6c6c1d63 DH |
475 | if (mode == afs_flock_mode_write && partial) |
476 | type = AFS_LOCK_WRITE; | |
e8d6c554 | 477 | |
6c6c1d63 | 478 | ret = afs_do_setlk_check(vnode, key, mode, type); |
e8d6c554 | 479 | if (ret < 0) |
0fafdc9f | 480 | return ret; |
e8d6c554 | 481 | |
d4696601 | 482 | trace_afs_flock_op(vnode, fl, afs_flock_op_set_lock); |
e8d6c554 | 483 | |
6c6c1d63 DH |
484 | /* AFS3 protocol only supports full-file locks and doesn't provide any |
485 | * method of upgrade/downgrade, so we need to emulate for partial-file | |
486 | * locks. | |
487 | * | |
488 | * The OpenAFS client only gets a server lock for a full-file lock and | |
489 | * keeps partial-file locks local. Allow this behaviour to be emulated | |
490 | * (as the default). | |
0fafdc9f | 491 | */ |
6c6c1d63 DH |
492 | if (mode == afs_flock_mode_local || |
493 | (partial && mode == afs_flock_mode_openafs)) { | |
494 | no_server_lock = true; | |
495 | goto skip_server_lock; | |
ff8e210a | 496 | } |
e8d6c554 | 497 | |
e8d6c554 | 498 | spin_lock(&vnode->lock); |
0fafdc9f | 499 | list_add_tail(&fl->fl_u.afs.link, &vnode->pending_locks); |
e8d6c554 | 500 | |
cdfb26b4 DH |
501 | ret = -ENOENT; |
502 | if (vnode->lock_state == AFS_VNODE_LOCK_DELETED) | |
503 | goto error_unlock; | |
504 | ||
4be5975a DH |
505 | /* If we've already got a lock on the server then try to move to having |
506 | * the VFS grant the requested lock. Note that this means that other | |
507 | * clients may get starved out. | |
0fafdc9f | 508 | */ |
4be5975a DH |
509 | _debug("try %u", vnode->lock_state); |
510 | if (vnode->lock_state == AFS_VNODE_LOCK_GRANTED) { | |
511 | if (type == AFS_LOCK_READ) { | |
512 | _debug("instant readlock"); | |
513 | list_move_tail(&fl->fl_u.afs.link, &vnode->granted_locks); | |
514 | fl->fl_u.afs.state = AFS_LOCK_GRANTED; | |
515 | goto vnode_is_locked_u; | |
516 | } | |
e8d6c554 | 517 | |
4be5975a DH |
518 | if (vnode->lock_type == AFS_LOCK_WRITE) { |
519 | _debug("instant writelock"); | |
520 | list_move_tail(&fl->fl_u.afs.link, &vnode->granted_locks); | |
521 | fl->fl_u.afs.state = AFS_LOCK_GRANTED; | |
522 | goto vnode_is_locked_u; | |
523 | } | |
524 | } | |
e8d6c554 | 525 | |
6c6c1d63 DH |
526 | if (vnode->lock_state == AFS_VNODE_LOCK_NONE && |
527 | !(fl->fl_flags & FL_SLEEP)) { | |
528 | ret = -EAGAIN; | |
529 | if (type == AFS_LOCK_READ) { | |
530 | if (vnode->status.lock_count == -1) | |
531 | goto lock_is_contended; /* Write locked */ | |
532 | } else { | |
533 | if (vnode->status.lock_count != 0) | |
534 | goto lock_is_contended; /* Locked */ | |
535 | } | |
536 | } | |
537 | ||
0fafdc9f DH |
538 | if (vnode->lock_state != AFS_VNODE_LOCK_NONE) |
539 | goto need_to_wait; | |
e8d6c554 | 540 | |
4be5975a | 541 | try_to_lock: |
0fafdc9f DH |
542 | /* We don't have a lock on this vnode and we aren't currently waiting |
543 | * for one either, so ask the server for a lock. | |
544 | * | |
545 | * Note that we need to be careful if we get interrupted by a signal | |
546 | * after dispatching the request as we may still get the lock, even | |
547 | * though we don't wait for the reply (it's not too bad a problem - the | |
4be5975a | 548 | * lock will expire in 5 mins anyway). |
0fafdc9f | 549 | */ |
d4696601 | 550 | trace_afs_flock_ev(vnode, fl, afs_flock_try_to_lock, 0); |
0fafdc9f DH |
551 | vnode->lock_key = key_get(key); |
552 | vnode->lock_type = type; | |
4be5975a | 553 | afs_set_lock_state(vnode, AFS_VNODE_LOCK_SETTING); |
e8d6c554 DH |
554 | spin_unlock(&vnode->lock); |
555 | ||
0fafdc9f | 556 | ret = afs_set_lock(vnode, key, type); /* RPC */ |
e8d6c554 DH |
557 | |
558 | spin_lock(&vnode->lock); | |
0fafdc9f | 559 | switch (ret) { |
4be5975a DH |
560 | case -EKEYREJECTED: |
561 | case -EKEYEXPIRED: | |
562 | case -EKEYREVOKED: | |
563 | case -EPERM: | |
564 | case -EACCES: | |
565 | fl->fl_u.afs.state = ret; | |
d4696601 | 566 | trace_afs_flock_ev(vnode, fl, afs_flock_fail_perm, ret); |
4be5975a DH |
567 | list_del_init(&fl->fl_u.afs.link); |
568 | afs_next_locker(vnode, ret); | |
569 | goto error_unlock; | |
570 | ||
cdfb26b4 DH |
571 | case -ENOENT: |
572 | fl->fl_u.afs.state = ret; | |
573 | trace_afs_flock_ev(vnode, fl, afs_flock_fail_other, ret); | |
574 | list_del_init(&fl->fl_u.afs.link); | |
575 | afs_kill_lockers_enoent(vnode); | |
576 | goto error_unlock; | |
577 | ||
0fafdc9f | 578 | default: |
4be5975a | 579 | fl->fl_u.afs.state = ret; |
d4696601 | 580 | trace_afs_flock_ev(vnode, fl, afs_flock_fail_other, ret); |
4be5975a DH |
581 | list_del_init(&fl->fl_u.afs.link); |
582 | afs_next_locker(vnode, 0); | |
583 | goto error_unlock; | |
e8d6c554 | 584 | |
0fafdc9f DH |
585 | case -EWOULDBLOCK: |
586 | /* The server doesn't have a lock-waiting queue, so the client | |
587 | * will have to retry. The server will break the outstanding | |
588 | * callbacks on a file when a lock is released. | |
589 | */ | |
0fafdc9f DH |
590 | ASSERT(list_empty(&vnode->granted_locks)); |
591 | ASSERTCMP(vnode->pending_locks.next, ==, &fl->fl_u.afs.link); | |
4be5975a | 592 | goto lock_is_contended; |
0fafdc9f DH |
593 | |
594 | case 0: | |
4be5975a | 595 | afs_set_lock_state(vnode, AFS_VNODE_LOCK_GRANTED); |
d4696601 | 596 | trace_afs_flock_ev(vnode, fl, afs_flock_acquired, type); |
4be5975a DH |
597 | afs_grant_locks(vnode); |
598 | goto vnode_is_locked_u; | |
e8d6c554 | 599 | } |
e8d6c554 | 600 | |
4be5975a | 601 | vnode_is_locked_u: |
0fafdc9f | 602 | spin_unlock(&vnode->lock); |
4be5975a DH |
603 | vnode_is_locked: |
604 | /* the lock has been granted by the server... */ | |
605 | ASSERTCMP(fl->fl_u.afs.state, ==, AFS_LOCK_GRANTED); | |
0fafdc9f | 606 | |
6c6c1d63 | 607 | skip_server_lock: |
4be5975a | 608 | /* ... but the VFS still needs to distribute access on this client. */ |
d4696601 | 609 | trace_afs_flock_ev(vnode, fl, afs_flock_vfs_locking, 0); |
4be5975a | 610 | ret = locks_lock_file_wait(file, fl); |
d4696601 | 611 | trace_afs_flock_ev(vnode, fl, afs_flock_vfs_lock, ret); |
e8d6c554 DH |
612 | if (ret < 0) |
613 | goto vfs_rejected_lock; | |
e8d6c554 | 614 | |
0fafdc9f | 615 | /* Again, make sure we've got a callback on this file and, again, make |
e8d6c554 | 616 | * sure that our view of the data version is up to date (we ignore |
0fafdc9f DH |
617 | * errors incurred here and deal with the consequences elsewhere). |
618 | */ | |
d2ddc776 | 619 | afs_validate(vnode, key); |
0fafdc9f DH |
620 | _leave(" = 0"); |
621 | return 0; | |
e8d6c554 | 622 | |
4be5975a DH |
623 | lock_is_contended: |
624 | if (!(fl->fl_flags & FL_SLEEP)) { | |
625 | list_del_init(&fl->fl_u.afs.link); | |
626 | afs_next_locker(vnode, 0); | |
627 | ret = -EAGAIN; | |
628 | goto error_unlock; | |
629 | } | |
630 | ||
631 | afs_set_lock_state(vnode, AFS_VNODE_LOCK_WAITING_FOR_CB); | |
d4696601 | 632 | trace_afs_flock_ev(vnode, fl, afs_flock_would_block, ret); |
4be5975a DH |
633 | queue_delayed_work(afs_lock_manager, &vnode->lock_work, HZ * 5); |
634 | ||
0fafdc9f DH |
635 | need_to_wait: |
636 | /* We're going to have to wait. Either this client doesn't have a lock | |
637 | * on the server yet and we need to wait for a callback to occur, or | |
4be5975a DH |
638 | * the client does have a lock on the server, but it's shared and we |
639 | * need an exclusive lock. | |
0fafdc9f | 640 | */ |
4be5975a | 641 | spin_unlock(&vnode->lock); |
0fafdc9f | 642 | |
d4696601 | 643 | trace_afs_flock_ev(vnode, fl, afs_flock_waiting, 0); |
4be5975a DH |
644 | ret = wait_event_interruptible(fl->fl_wait, |
645 | fl->fl_u.afs.state != AFS_LOCK_PENDING); | |
d4696601 | 646 | trace_afs_flock_ev(vnode, fl, afs_flock_waited, ret); |
0fafdc9f | 647 | |
4be5975a | 648 | if (fl->fl_u.afs.state >= 0 && fl->fl_u.afs.state != AFS_LOCK_GRANTED) { |
0fafdc9f | 649 | spin_lock(&vnode->lock); |
0fafdc9f | 650 | |
4be5975a DH |
651 | switch (fl->fl_u.afs.state) { |
652 | case AFS_LOCK_YOUR_TRY: | |
653 | fl->fl_u.afs.state = AFS_LOCK_PENDING; | |
654 | goto try_to_lock; | |
655 | case AFS_LOCK_PENDING: | |
656 | if (ret > 0) { | |
657 | /* We need to retry the lock. We may not be | |
658 | * notified by the server if it just expired | |
659 | * rather than being released. | |
660 | */ | |
661 | ASSERTCMP(vnode->lock_state, ==, AFS_VNODE_LOCK_WAITING_FOR_CB); | |
662 | afs_set_lock_state(vnode, AFS_VNODE_LOCK_SETTING); | |
663 | fl->fl_u.afs.state = AFS_LOCK_PENDING; | |
664 | goto try_to_lock; | |
665 | } | |
666 | goto error_unlock; | |
667 | case AFS_LOCK_GRANTED: | |
668 | default: | |
669 | break; | |
670 | } | |
0fafdc9f | 671 | |
4be5975a DH |
672 | spin_unlock(&vnode->lock); |
673 | } | |
0fafdc9f | 674 | |
4be5975a DH |
675 | if (fl->fl_u.afs.state == AFS_LOCK_GRANTED) |
676 | goto vnode_is_locked; | |
677 | ret = fl->fl_u.afs.state; | |
678 | goto error; | |
e8d6c554 DH |
679 | |
680 | vfs_rejected_lock: | |
0fafdc9f DH |
681 | /* The VFS rejected the lock we just obtained, so we have to discard |
682 | * what we just got. We defer this to the lock manager work item to | |
683 | * deal with. | |
684 | */ | |
e8d6c554 | 685 | _debug("vfs refused %d", ret); |
6c6c1d63 DH |
686 | if (no_server_lock) |
687 | goto error; | |
0fafdc9f | 688 | spin_lock(&vnode->lock); |
e8d6c554 | 689 | list_del_init(&fl->fl_u.afs.link); |
4be5975a DH |
690 | afs_defer_unlock(vnode); |
691 | ||
692 | error_unlock: | |
693 | spin_unlock(&vnode->lock); | |
694 | error: | |
695 | _leave(" = %d", ret); | |
696 | return ret; | |
e8d6c554 DH |
697 | } |
698 | ||
699 | /* | |
700 | * unlock on a file on the server | |
701 | */ | |
702 | static int afs_do_unlk(struct file *file, struct file_lock *fl) | |
703 | { | |
0fafdc9f | 704 | struct afs_vnode *vnode = AFS_FS_I(locks_inode(file)); |
e8d6c554 DH |
705 | int ret; |
706 | ||
3b6492df | 707 | _enter("{%llx:%llu},%u", vnode->fid.vid, vnode->fid.vnode, fl->fl_type); |
e8d6c554 | 708 | |
d4696601 DH |
709 | trace_afs_flock_op(vnode, fl, afs_flock_op_unlock); |
710 | ||
0fafdc9f DH |
711 | /* Flush all pending writes before doing anything with locks. */ |
712 | vfs_fsync(file, 0); | |
713 | ||
4be5975a | 714 | ret = locks_lock_file_wait(file, fl); |
0fafdc9f DH |
715 | _leave(" = %d [%u]", ret, vnode->lock_state); |
716 | return ret; | |
e8d6c554 DH |
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 | { | |
0fafdc9f | 724 | struct afs_vnode *vnode = AFS_FS_I(locks_inode(file)); |
215804a9 | 725 | struct key *key = afs_file_key(file); |
e8d6c554 DH |
726 | int ret, lock_count; |
727 | ||
728 | _enter(""); | |
729 | ||
cdfb26b4 DH |
730 | if (vnode->lock_state == AFS_VNODE_LOCK_DELETED) |
731 | return -ENOENT; | |
732 | ||
e8d6c554 DH |
733 | fl->fl_type = F_UNLCK; |
734 | ||
e8d6c554 | 735 | /* check local lock records first */ |
275afcac AM |
736 | posix_test_lock(file, fl); |
737 | if (fl->fl_type == F_UNLCK) { | |
e8d6c554 | 738 | /* no local locks; consult the server */ |
a58823ac | 739 | ret = afs_fetch_status(vnode, key, false, NULL); |
e8d6c554 DH |
740 | if (ret < 0) |
741 | goto error; | |
0fafdc9f DH |
742 | |
743 | lock_count = READ_ONCE(vnode->status.lock_count); | |
68ce801f DH |
744 | if (lock_count != 0) { |
745 | if (lock_count > 0) | |
746 | fl->fl_type = F_RDLCK; | |
747 | else | |
748 | fl->fl_type = F_WRLCK; | |
749 | fl->fl_start = 0; | |
750 | fl->fl_end = OFFSET_MAX; | |
751 | fl->fl_pid = 0; | |
752 | } | |
e8d6c554 DH |
753 | } |
754 | ||
0fafdc9f | 755 | ret = 0; |
e8d6c554 | 756 | error: |
e8d6c554 DH |
757 | _leave(" = %d [%hd]", ret, fl->fl_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 | { | |
0fafdc9f | 766 | struct afs_vnode *vnode = AFS_FS_I(locks_inode(file)); |
d4696601 DH |
767 | enum afs_flock_operation op; |
768 | int ret; | |
e8d6c554 | 769 | |
3b6492df | 770 | _enter("{%llx:%llu},%d,{t=%x,fl=%x,r=%Ld:%Ld}", |
e8d6c554 DH |
771 | vnode->fid.vid, vnode->fid.vnode, cmd, |
772 | fl->fl_type, fl->fl_flags, | |
773 | (long long) fl->fl_start, (long long) fl->fl_end); | |
774 | ||
775 | /* AFS doesn't support mandatory locks */ | |
fc5846e5 | 776 | if (__mandatory_lock(&vnode->vfs_inode) && fl->fl_type != F_UNLCK) |
e8d6c554 DH |
777 | return -ENOLCK; |
778 | ||
779 | if (IS_GETLK(cmd)) | |
780 | return afs_do_getlk(file, fl); | |
d4696601 DH |
781 | |
782 | fl->fl_u.afs.debug_id = atomic_inc_return(&afs_file_lock_debug_id); | |
783 | trace_afs_flock_op(vnode, fl, afs_flock_op_lock); | |
784 | ||
e8d6c554 | 785 | if (fl->fl_type == F_UNLCK) |
d4696601 DH |
786 | ret = afs_do_unlk(file, fl); |
787 | else | |
788 | ret = afs_do_setlk(file, fl); | |
789 | ||
790 | switch (ret) { | |
791 | case 0: op = afs_flock_op_return_ok; break; | |
792 | case -EAGAIN: op = afs_flock_op_return_eagain; break; | |
793 | case -EDEADLK: op = afs_flock_op_return_edeadlk; break; | |
794 | default: op = afs_flock_op_return_error; break; | |
795 | } | |
796 | trace_afs_flock_op(vnode, fl, op); | |
797 | return ret; | |
e8d6c554 DH |
798 | } |
799 | ||
800 | /* | |
801 | * manage FLOCK locks on a file | |
802 | */ | |
803 | int afs_flock(struct file *file, int cmd, struct file_lock *fl) | |
804 | { | |
0fafdc9f | 805 | struct afs_vnode *vnode = AFS_FS_I(locks_inode(file)); |
d4696601 DH |
806 | enum afs_flock_operation op; |
807 | int ret; | |
e8d6c554 | 808 | |
3b6492df | 809 | _enter("{%llx:%llu},%d,{t=%x,fl=%x}", |
e8d6c554 DH |
810 | vnode->fid.vid, vnode->fid.vnode, cmd, |
811 | fl->fl_type, fl->fl_flags); | |
812 | ||
813 | /* | |
814 | * No BSD flocks over NFS allowed. | |
815 | * Note: we could try to fake a POSIX lock request here by | |
816 | * using ((u32) filp | 0x80000000) or some such as the pid. | |
817 | * Not sure whether that would be unique, though, or whether | |
818 | * that would break in other places. | |
819 | */ | |
820 | if (!(fl->fl_flags & FL_FLOCK)) | |
821 | return -ENOLCK; | |
822 | ||
d4696601 DH |
823 | fl->fl_u.afs.debug_id = atomic_inc_return(&afs_file_lock_debug_id); |
824 | trace_afs_flock_op(vnode, fl, afs_flock_op_flock); | |
825 | ||
e8d6c554 | 826 | /* we're simulating flock() locks using posix locks on the server */ |
e8d6c554 | 827 | if (fl->fl_type == F_UNLCK) |
d4696601 DH |
828 | ret = afs_do_unlk(file, fl); |
829 | else | |
830 | ret = afs_do_setlk(file, fl); | |
831 | ||
832 | switch (ret) { | |
833 | case 0: op = afs_flock_op_return_ok; break; | |
834 | case -EAGAIN: op = afs_flock_op_return_eagain; break; | |
835 | case -EDEADLK: op = afs_flock_op_return_edeadlk; break; | |
836 | default: op = afs_flock_op_return_error; break; | |
837 | } | |
838 | trace_afs_flock_op(vnode, fl, op); | |
839 | return ret; | |
e8d6c554 DH |
840 | } |
841 | ||
842 | /* | |
843 | * the POSIX lock management core VFS code copies the lock record and adds the | |
844 | * copy into its own list, so we need to add that copy to the vnode's lock | |
845 | * queue in the same place as the original (which will be deleted shortly | |
846 | * after) | |
847 | */ | |
848 | static void afs_fl_copy_lock(struct file_lock *new, struct file_lock *fl) | |
849 | { | |
0fafdc9f DH |
850 | struct afs_vnode *vnode = AFS_FS_I(locks_inode(fl->fl_file)); |
851 | ||
e8d6c554 DH |
852 | _enter(""); |
853 | ||
d4696601 DH |
854 | new->fl_u.afs.debug_id = atomic_inc_return(&afs_file_lock_debug_id); |
855 | ||
0fafdc9f | 856 | spin_lock(&vnode->lock); |
d4696601 | 857 | trace_afs_flock_op(vnode, new, afs_flock_op_copy_lock); |
e8d6c554 | 858 | list_add(&new->fl_u.afs.link, &fl->fl_u.afs.link); |
0fafdc9f | 859 | spin_unlock(&vnode->lock); |
e8d6c554 DH |
860 | } |
861 | ||
862 | /* | |
863 | * need to remove this lock from the vnode queue when it's removed from the | |
864 | * VFS's list | |
865 | */ | |
866 | static void afs_fl_release_private(struct file_lock *fl) | |
867 | { | |
0fafdc9f DH |
868 | struct afs_vnode *vnode = AFS_FS_I(locks_inode(fl->fl_file)); |
869 | ||
e8d6c554 DH |
870 | _enter(""); |
871 | ||
0fafdc9f | 872 | spin_lock(&vnode->lock); |
4be5975a | 873 | |
d4696601 | 874 | trace_afs_flock_op(vnode, fl, afs_flock_op_release_lock); |
4be5975a DH |
875 | list_del_init(&fl->fl_u.afs.link); |
876 | if (list_empty(&vnode->granted_locks)) | |
877 | afs_defer_unlock(vnode); | |
878 | ||
0fafdc9f DH |
879 | _debug("state %u for %p", vnode->lock_state, vnode); |
880 | spin_unlock(&vnode->lock); | |
e8d6c554 | 881 | } |