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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 | |
4be5975a | 16 | #define AFS_LOCK_YOUR_TRY 2 |
e8d6c554 | 17 | |
f044c884 DH |
18 | struct workqueue_struct *afs_lock_manager; |
19 | ||
4be5975a | 20 | static void afs_next_locker(struct afs_vnode *vnode, int error); |
e8d6c554 DH |
21 | static void afs_fl_copy_lock(struct file_lock *new, struct file_lock *fl); |
22 | static void afs_fl_release_private(struct file_lock *fl); | |
23 | ||
6aed6285 | 24 | static const struct file_lock_operations afs_lock_ops = { |
e8d6c554 DH |
25 | .fl_copy_lock = afs_fl_copy_lock, |
26 | .fl_release_private = afs_fl_release_private, | |
27 | }; | |
28 | ||
4be5975a DH |
29 | static inline void afs_set_lock_state(struct afs_vnode *vnode, enum afs_lock_state state) |
30 | { | |
31 | _debug("STATE %u -> %u", vnode->lock_state, state); | |
32 | vnode->lock_state = state; | |
33 | } | |
34 | ||
d4696601 DH |
35 | static atomic_t afs_file_lock_debug_id; |
36 | ||
e8d6c554 DH |
37 | /* |
38 | * if the callback is broken on this vnode, then the lock may now be available | |
39 | */ | |
40 | void afs_lock_may_be_available(struct afs_vnode *vnode) | |
41 | { | |
3b6492df | 42 | _enter("{%llx:%llu}", vnode->fid.vid, vnode->fid.vnode); |
e8d6c554 | 43 | |
4be5975a DH |
44 | spin_lock(&vnode->lock); |
45 | if (vnode->lock_state == AFS_VNODE_LOCK_WAITING_FOR_CB) | |
46 | afs_next_locker(vnode, 0); | |
d4696601 | 47 | trace_afs_flock_ev(vnode, NULL, afs_flock_callback_break, 0); |
4be5975a | 48 | spin_unlock(&vnode->lock); |
e8d6c554 DH |
49 | } |
50 | ||
51 | /* | |
52 | * the lock will time out in 5 minutes unless we extend it, so schedule | |
53 | * extension in a bit less than that time | |
54 | */ | |
55 | static void afs_schedule_lock_extension(struct afs_vnode *vnode) | |
56 | { | |
a690f60a DH |
57 | ktime_t expires_at, now, duration; |
58 | u64 duration_j; | |
59 | ||
60 | expires_at = ktime_add_ms(vnode->locked_at, AFS_LOCKWAIT * 1000 / 2); | |
61 | now = ktime_get_real(); | |
62 | duration = ktime_sub(expires_at, now); | |
63 | if (duration <= 0) | |
64 | duration_j = 0; | |
65 | else | |
66 | duration_j = nsecs_to_jiffies(ktime_to_ns(duration)); | |
67 | ||
68 | queue_delayed_work(afs_lock_manager, &vnode->lock_work, duration_j); | |
69 | } | |
70 | ||
71 | /* | |
72 | * In the case of successful completion of a lock operation, record the time | |
73 | * the reply appeared and start the lock extension timer. | |
74 | */ | |
75 | void afs_lock_op_done(struct afs_call *call) | |
76 | { | |
a58823ac | 77 | struct afs_vnode *vnode = call->lvnode; |
a690f60a DH |
78 | |
79 | if (call->error == 0) { | |
80 | spin_lock(&vnode->lock); | |
d4696601 | 81 | trace_afs_flock_ev(vnode, NULL, afs_flock_timestamp, 0); |
a690f60a DH |
82 | vnode->locked_at = call->reply_time; |
83 | afs_schedule_lock_extension(vnode); | |
84 | spin_unlock(&vnode->lock); | |
85 | } | |
e8d6c554 DH |
86 | } |
87 | ||
ff8e210a DH |
88 | /* |
89 | * grant one or more locks (readlocks are allowed to jump the queue if the | |
90 | * first lock in the queue is itself a readlock) | |
91 | * - the caller must hold the vnode lock | |
92 | */ | |
4be5975a | 93 | static void afs_grant_locks(struct afs_vnode *vnode) |
ff8e210a DH |
94 | { |
95 | struct file_lock *p, *_p; | |
4be5975a | 96 | bool exclusive = (vnode->lock_type == AFS_LOCK_WRITE); |
ff8e210a | 97 | |
4be5975a DH |
98 | list_for_each_entry_safe(p, _p, &vnode->pending_locks, fl_u.afs.link) { |
99 | if (!exclusive && p->fl_type == F_WRLCK) | |
100 | continue; | |
101 | ||
102 | list_move_tail(&p->fl_u.afs.link, &vnode->granted_locks); | |
103 | p->fl_u.afs.state = AFS_LOCK_GRANTED; | |
d4696601 | 104 | trace_afs_flock_op(vnode, p, afs_flock_op_grant); |
4be5975a DH |
105 | wake_up(&p->fl_wait); |
106 | } | |
107 | } | |
108 | ||
109 | /* | |
110 | * If an error is specified, reject every pending lock that matches the | |
111 | * authentication and type of the lock we failed to get. If there are any | |
112 | * remaining lockers, try to wake up one of them to have a go. | |
113 | */ | |
114 | static void afs_next_locker(struct afs_vnode *vnode, int error) | |
115 | { | |
116 | struct file_lock *p, *_p, *next = NULL; | |
117 | struct key *key = vnode->lock_key; | |
118 | unsigned int fl_type = F_RDLCK; | |
119 | ||
120 | _enter(""); | |
121 | ||
122 | if (vnode->lock_type == AFS_LOCK_WRITE) | |
123 | fl_type = F_WRLCK; | |
124 | ||
125 | list_for_each_entry_safe(p, _p, &vnode->pending_locks, fl_u.afs.link) { | |
126 | if (error && | |
127 | p->fl_type == fl_type && | |
128 | afs_file_key(p->fl_file) == key) { | |
129 | list_del_init(&p->fl_u.afs.link); | |
130 | p->fl_u.afs.state = error; | |
131 | wake_up(&p->fl_wait); | |
ff8e210a | 132 | } |
4be5975a DH |
133 | |
134 | /* Select the next locker to hand off to. */ | |
135 | if (next && | |
136 | (next->fl_type == F_WRLCK || p->fl_type == F_RDLCK)) | |
137 | continue; | |
138 | next = p; | |
ff8e210a | 139 | } |
4be5975a DH |
140 | |
141 | vnode->lock_key = NULL; | |
142 | key_put(key); | |
143 | ||
144 | if (next) { | |
145 | afs_set_lock_state(vnode, AFS_VNODE_LOCK_SETTING); | |
146 | next->fl_u.afs.state = AFS_LOCK_YOUR_TRY; | |
d4696601 | 147 | trace_afs_flock_op(vnode, next, afs_flock_op_wake); |
4be5975a DH |
148 | wake_up(&next->fl_wait); |
149 | } else { | |
150 | afs_set_lock_state(vnode, AFS_VNODE_LOCK_NONE); | |
d4696601 | 151 | trace_afs_flock_ev(vnode, NULL, afs_flock_no_lockers, 0); |
4be5975a DH |
152 | } |
153 | ||
154 | _leave(""); | |
ff8e210a DH |
155 | } |
156 | ||
cdfb26b4 DH |
157 | /* |
158 | * Kill off all waiters in the the pending lock queue due to the vnode being | |
159 | * deleted. | |
160 | */ | |
161 | static void afs_kill_lockers_enoent(struct afs_vnode *vnode) | |
162 | { | |
163 | struct file_lock *p; | |
164 | ||
165 | afs_set_lock_state(vnode, AFS_VNODE_LOCK_DELETED); | |
166 | ||
167 | while (!list_empty(&vnode->pending_locks)) { | |
168 | p = list_entry(vnode->pending_locks.next, | |
169 | struct file_lock, fl_u.afs.link); | |
170 | list_del_init(&p->fl_u.afs.link); | |
171 | p->fl_u.afs.state = -ENOENT; | |
172 | wake_up(&p->fl_wait); | |
173 | } | |
174 | ||
175 | key_put(vnode->lock_key); | |
176 | vnode->lock_key = NULL; | |
ff8e210a DH |
177 | } |
178 | ||
d2ddc776 DH |
179 | /* |
180 | * Get a lock on a file | |
181 | */ | |
182 | static int afs_set_lock(struct afs_vnode *vnode, struct key *key, | |
183 | afs_lock_type_t type) | |
184 | { | |
a58823ac | 185 | struct afs_status_cb *scb; |
d2ddc776 DH |
186 | struct afs_fs_cursor fc; |
187 | int ret; | |
188 | ||
3b6492df | 189 | _enter("%s{%llx:%llu.%u},%x,%u", |
d2ddc776 DH |
190 | vnode->volume->name, |
191 | vnode->fid.vid, | |
192 | vnode->fid.vnode, | |
193 | vnode->fid.unique, | |
194 | key_serial(key), type); | |
195 | ||
a58823ac DH |
196 | scb = kzalloc(sizeof(struct afs_status_cb), GFP_KERNEL); |
197 | if (!scb) | |
198 | return -ENOMEM; | |
199 | ||
d2ddc776 | 200 | ret = -ERESTARTSYS; |
20b8391f | 201 | if (afs_begin_vnode_operation(&fc, vnode, key, true)) { |
d2ddc776 | 202 | while (afs_select_fileserver(&fc)) { |
68251f0a | 203 | fc.cb_break = afs_calc_vnode_cb_break(vnode); |
a58823ac | 204 | afs_fs_set_lock(&fc, type, scb); |
d2ddc776 DH |
205 | } |
206 | ||
a58823ac DH |
207 | afs_check_for_remote_deletion(&fc, vnode); |
208 | afs_vnode_commit_status(&fc, vnode, fc.cb_break, NULL, scb); | |
d2ddc776 DH |
209 | ret = afs_end_vnode_operation(&fc); |
210 | } | |
211 | ||
a58823ac | 212 | kfree(scb); |
d2ddc776 DH |
213 | _leave(" = %d", ret); |
214 | return ret; | |
215 | } | |
216 | ||
217 | /* | |
218 | * Extend a lock on a file | |
219 | */ | |
220 | static int afs_extend_lock(struct afs_vnode *vnode, struct key *key) | |
221 | { | |
a58823ac | 222 | struct afs_status_cb *scb; |
d2ddc776 DH |
223 | struct afs_fs_cursor fc; |
224 | int ret; | |
225 | ||
3b6492df | 226 | _enter("%s{%llx:%llu.%u},%x", |
d2ddc776 DH |
227 | vnode->volume->name, |
228 | vnode->fid.vid, | |
229 | vnode->fid.vnode, | |
230 | vnode->fid.unique, | |
231 | key_serial(key)); | |
232 | ||
a58823ac DH |
233 | scb = kzalloc(sizeof(struct afs_status_cb), GFP_KERNEL); |
234 | if (!scb) | |
235 | return -ENOMEM; | |
236 | ||
d2ddc776 | 237 | ret = -ERESTARTSYS; |
20b8391f | 238 | if (afs_begin_vnode_operation(&fc, vnode, key, false)) { |
d2ddc776 | 239 | while (afs_select_current_fileserver(&fc)) { |
68251f0a | 240 | fc.cb_break = afs_calc_vnode_cb_break(vnode); |
a58823ac | 241 | afs_fs_extend_lock(&fc, scb); |
d2ddc776 DH |
242 | } |
243 | ||
a58823ac DH |
244 | afs_check_for_remote_deletion(&fc, vnode); |
245 | afs_vnode_commit_status(&fc, vnode, fc.cb_break, NULL, scb); | |
d2ddc776 DH |
246 | ret = afs_end_vnode_operation(&fc); |
247 | } | |
248 | ||
a58823ac | 249 | kfree(scb); |
d2ddc776 DH |
250 | _leave(" = %d", ret); |
251 | return ret; | |
252 | } | |
253 | ||
254 | /* | |
255 | * Release a lock on a file | |
256 | */ | |
257 | static int afs_release_lock(struct afs_vnode *vnode, struct key *key) | |
258 | { | |
a58823ac | 259 | struct afs_status_cb *scb; |
d2ddc776 DH |
260 | struct afs_fs_cursor fc; |
261 | int ret; | |
262 | ||
3b6492df | 263 | _enter("%s{%llx:%llu.%u},%x", |
d2ddc776 DH |
264 | vnode->volume->name, |
265 | vnode->fid.vid, | |
266 | vnode->fid.vnode, | |
267 | vnode->fid.unique, | |
268 | key_serial(key)); | |
269 | ||
a58823ac DH |
270 | scb = kzalloc(sizeof(struct afs_status_cb), GFP_KERNEL); |
271 | if (!scb) | |
272 | return -ENOMEM; | |
273 | ||
d2ddc776 | 274 | ret = -ERESTARTSYS; |
20b8391f | 275 | if (afs_begin_vnode_operation(&fc, vnode, key, false)) { |
d2ddc776 | 276 | while (afs_select_current_fileserver(&fc)) { |
68251f0a | 277 | fc.cb_break = afs_calc_vnode_cb_break(vnode); |
a58823ac | 278 | afs_fs_release_lock(&fc, scb); |
d2ddc776 DH |
279 | } |
280 | ||
a58823ac DH |
281 | afs_check_for_remote_deletion(&fc, vnode); |
282 | afs_vnode_commit_status(&fc, vnode, fc.cb_break, NULL, scb); | |
d2ddc776 DH |
283 | ret = afs_end_vnode_operation(&fc); |
284 | } | |
285 | ||
a58823ac | 286 | kfree(scb); |
d2ddc776 DH |
287 | _leave(" = %d", ret); |
288 | return ret; | |
289 | } | |
290 | ||
e8d6c554 DH |
291 | /* |
292 | * do work for a lock, including: | |
293 | * - probing for a lock we're waiting on but didn't get immediately | |
294 | * - extending a lock that's close to timing out | |
295 | */ | |
296 | void afs_lock_work(struct work_struct *work) | |
297 | { | |
298 | struct afs_vnode *vnode = | |
299 | container_of(work, struct afs_vnode, lock_work.work); | |
e8d6c554 DH |
300 | struct key *key; |
301 | int ret; | |
302 | ||
3b6492df | 303 | _enter("{%llx:%llu}", vnode->fid.vid, vnode->fid.vnode); |
e8d6c554 DH |
304 | |
305 | spin_lock(&vnode->lock); | |
306 | ||
0fafdc9f DH |
307 | again: |
308 | _debug("wstate %u for %p", vnode->lock_state, vnode); | |
309 | switch (vnode->lock_state) { | |
310 | case AFS_VNODE_LOCK_NEED_UNLOCK: | |
4be5975a | 311 | afs_set_lock_state(vnode, AFS_VNODE_LOCK_UNLOCKING); |
d4696601 | 312 | trace_afs_flock_ev(vnode, NULL, afs_flock_work_unlocking, 0); |
e8d6c554 DH |
313 | spin_unlock(&vnode->lock); |
314 | ||
315 | /* attempt to release the server lock; if it fails, we just | |
0fafdc9f DH |
316 | * wait 5 minutes and it'll expire anyway */ |
317 | ret = afs_release_lock(vnode, vnode->lock_key); | |
79ddbfa5 | 318 | if (ret < 0 && vnode->lock_state != AFS_VNODE_LOCK_DELETED) { |
cdfb26b4 DH |
319 | trace_afs_flock_ev(vnode, NULL, afs_flock_release_fail, |
320 | ret); | |
e8d6c554 | 321 | printk(KERN_WARNING "AFS:" |
3b6492df | 322 | " Failed to release lock on {%llx:%llx} error %d\n", |
e8d6c554 | 323 | vnode->fid.vid, vnode->fid.vnode, ret); |
0fafdc9f DH |
324 | } |
325 | ||
e8d6c554 | 326 | spin_lock(&vnode->lock); |
cdfb26b4 DH |
327 | if (ret == -ENOENT) |
328 | afs_kill_lockers_enoent(vnode); | |
329 | else | |
330 | afs_next_locker(vnode, 0); | |
4be5975a DH |
331 | spin_unlock(&vnode->lock); |
332 | return; | |
e8d6c554 | 333 | |
0fafdc9f DH |
334 | /* If we've already got a lock, then it must be time to extend that |
335 | * lock as AFS locks time out after 5 minutes. | |
336 | */ | |
337 | case AFS_VNODE_LOCK_GRANTED: | |
e8d6c554 DH |
338 | _debug("extend"); |
339 | ||
0fafdc9f DH |
340 | ASSERT(!list_empty(&vnode->granted_locks)); |
341 | ||
342 | key = key_get(vnode->lock_key); | |
4be5975a | 343 | afs_set_lock_state(vnode, AFS_VNODE_LOCK_EXTENDING); |
d4696601 | 344 | trace_afs_flock_ev(vnode, NULL, afs_flock_work_extending, 0); |
e8d6c554 DH |
345 | spin_unlock(&vnode->lock); |
346 | ||
0fafdc9f | 347 | ret = afs_extend_lock(vnode, key); /* RPC */ |
e8d6c554 | 348 | key_put(key); |
0fafdc9f | 349 | |
cdfb26b4 DH |
350 | if (ret < 0) { |
351 | trace_afs_flock_ev(vnode, NULL, afs_flock_extend_fail, | |
352 | ret); | |
3b6492df | 353 | pr_warning("AFS: Failed to extend lock on {%llx:%llx} error %d\n", |
0fafdc9f | 354 | vnode->fid.vid, vnode->fid.vnode, ret); |
cdfb26b4 | 355 | } |
0fafdc9f DH |
356 | |
357 | spin_lock(&vnode->lock); | |
358 | ||
cdfb26b4 DH |
359 | if (ret == -ENOENT) { |
360 | afs_kill_lockers_enoent(vnode); | |
361 | spin_unlock(&vnode->lock); | |
362 | return; | |
363 | } | |
364 | ||
0fafdc9f DH |
365 | if (vnode->lock_state != AFS_VNODE_LOCK_EXTENDING) |
366 | goto again; | |
4be5975a | 367 | afs_set_lock_state(vnode, AFS_VNODE_LOCK_GRANTED); |
0fafdc9f | 368 | |
4be5975a | 369 | if (ret != 0) |
e8d6c554 DH |
370 | queue_delayed_work(afs_lock_manager, &vnode->lock_work, |
371 | HZ * 10); | |
0fafdc9f DH |
372 | spin_unlock(&vnode->lock); |
373 | _leave(" [ext]"); | |
e8d6c554 | 374 | return; |
e8d6c554 | 375 | |
4be5975a DH |
376 | /* If we're waiting for a callback to indicate lock release, we can't |
377 | * actually rely on this, so need to recheck at regular intervals. The | |
378 | * problem is that the server might not notify us if the lock just | |
379 | * expires (say because a client died) rather than being explicitly | |
380 | * released. | |
381 | */ | |
0fafdc9f | 382 | case AFS_VNODE_LOCK_WAITING_FOR_CB: |
4be5975a DH |
383 | _debug("retry"); |
384 | afs_next_locker(vnode, 0); | |
e8d6c554 | 385 | spin_unlock(&vnode->lock); |
4be5975a | 386 | return; |
e8d6c554 | 387 | |
cdfb26b4 DH |
388 | case AFS_VNODE_LOCK_DELETED: |
389 | afs_kill_lockers_enoent(vnode); | |
390 | spin_unlock(&vnode->lock); | |
391 | return; | |
0fafdc9f | 392 | |
e690c9e3 | 393 | /* Fall through */ |
0fafdc9f DH |
394 | default: |
395 | /* Looks like a lock request was withdrawn. */ | |
396 | spin_unlock(&vnode->lock); | |
397 | _leave(" [no]"); | |
e8d6c554 DH |
398 | return; |
399 | } | |
e8d6c554 DH |
400 | } |
401 | ||
402 | /* | |
403 | * pass responsibility for the unlocking of a vnode on the server to the | |
404 | * manager thread, lest a pending signal in the calling thread interrupt | |
405 | * AF_RXRPC | |
406 | * - the caller must hold the vnode lock | |
407 | */ | |
0fafdc9f | 408 | static void afs_defer_unlock(struct afs_vnode *vnode) |
e8d6c554 | 409 | { |
4be5975a | 410 | _enter("%u", vnode->lock_state); |
0fafdc9f | 411 | |
4be5975a DH |
412 | if (list_empty(&vnode->granted_locks) && |
413 | (vnode->lock_state == AFS_VNODE_LOCK_GRANTED || | |
414 | vnode->lock_state == AFS_VNODE_LOCK_EXTENDING)) { | |
0fafdc9f DH |
415 | cancel_delayed_work(&vnode->lock_work); |
416 | ||
4be5975a | 417 | afs_set_lock_state(vnode, AFS_VNODE_LOCK_NEED_UNLOCK); |
d4696601 | 418 | trace_afs_flock_ev(vnode, NULL, afs_flock_defer_unlock, 0); |
4be5975a | 419 | queue_delayed_work(afs_lock_manager, &vnode->lock_work, 0); |
0fafdc9f DH |
420 | } |
421 | } | |
422 | ||
423 | /* | |
424 | * Check that our view of the file metadata is up to date and check to see | |
425 | * whether we think that we have a locking permit. | |
426 | */ | |
427 | static int afs_do_setlk_check(struct afs_vnode *vnode, struct key *key, | |
6c6c1d63 | 428 | enum afs_flock_mode mode, afs_lock_type_t type) |
0fafdc9f DH |
429 | { |
430 | afs_access_t access; | |
431 | int ret; | |
432 | ||
433 | /* Make sure we've got a callback on this file and that our view of the | |
434 | * data version is up to date. | |
435 | */ | |
436 | ret = afs_validate(vnode, key); | |
437 | if (ret < 0) | |
438 | return ret; | |
439 | ||
440 | /* Check the permission set to see if we're actually going to be | |
441 | * allowed to get a lock on this file. | |
442 | */ | |
443 | ret = afs_check_permit(vnode, key, &access); | |
444 | if (ret < 0) | |
445 | return ret; | |
446 | ||
447 | /* At a rough estimation, you need LOCK, WRITE or INSERT perm to | |
448 | * read-lock a file and WRITE or INSERT perm to write-lock a file. | |
449 | * | |
450 | * We can't rely on the server to do this for us since if we want to | |
451 | * share a read lock that we already have, we won't go the server. | |
452 | */ | |
453 | if (type == AFS_LOCK_READ) { | |
454 | if (!(access & (AFS_ACE_INSERT | AFS_ACE_WRITE | AFS_ACE_LOCK))) | |
455 | return -EACCES; | |
0fafdc9f DH |
456 | } else { |
457 | if (!(access & (AFS_ACE_INSERT | AFS_ACE_WRITE))) | |
458 | return -EACCES; | |
0fafdc9f DH |
459 | } |
460 | ||
461 | return 0; | |
462 | } | |
463 | ||
e8d6c554 DH |
464 | /* |
465 | * request a lock on a file on the server | |
466 | */ | |
467 | static int afs_do_setlk(struct file *file, struct file_lock *fl) | |
468 | { | |
0fafdc9f | 469 | struct inode *inode = locks_inode(file); |
1c8c601a | 470 | struct afs_vnode *vnode = AFS_FS_I(inode); |
6c6c1d63 | 471 | enum afs_flock_mode mode = AFS_FS_S(inode->i_sb)->flock_mode; |
e8d6c554 | 472 | afs_lock_type_t type; |
215804a9 | 473 | struct key *key = afs_file_key(file); |
6c6c1d63 | 474 | bool partial, no_server_lock = false; |
e8d6c554 DH |
475 | int ret; |
476 | ||
6c6c1d63 DH |
477 | if (mode == afs_flock_mode_unset) |
478 | mode = afs_flock_mode_openafs; | |
e8d6c554 | 479 | |
6c6c1d63 DH |
480 | _enter("{%llx:%llu},%llu-%llu,%u,%u", |
481 | vnode->fid.vid, vnode->fid.vnode, | |
482 | fl->fl_start, fl->fl_end, fl->fl_type, mode); | |
e8d6c554 | 483 | |
e8d6c554 DH |
484 | fl->fl_ops = &afs_lock_ops; |
485 | INIT_LIST_HEAD(&fl->fl_u.afs.link); | |
486 | fl->fl_u.afs.state = AFS_LOCK_PENDING; | |
487 | ||
6c6c1d63 | 488 | partial = (fl->fl_start != 0 || fl->fl_end != OFFSET_MAX); |
e8d6c554 | 489 | type = (fl->fl_type == F_RDLCK) ? AFS_LOCK_READ : AFS_LOCK_WRITE; |
6c6c1d63 DH |
490 | if (mode == afs_flock_mode_write && partial) |
491 | type = AFS_LOCK_WRITE; | |
e8d6c554 | 492 | |
6c6c1d63 | 493 | ret = afs_do_setlk_check(vnode, key, mode, type); |
e8d6c554 | 494 | if (ret < 0) |
0fafdc9f | 495 | return ret; |
e8d6c554 | 496 | |
d4696601 | 497 | trace_afs_flock_op(vnode, fl, afs_flock_op_set_lock); |
e8d6c554 | 498 | |
6c6c1d63 DH |
499 | /* AFS3 protocol only supports full-file locks and doesn't provide any |
500 | * method of upgrade/downgrade, so we need to emulate for partial-file | |
501 | * locks. | |
502 | * | |
503 | * The OpenAFS client only gets a server lock for a full-file lock and | |
504 | * keeps partial-file locks local. Allow this behaviour to be emulated | |
505 | * (as the default). | |
0fafdc9f | 506 | */ |
6c6c1d63 DH |
507 | if (mode == afs_flock_mode_local || |
508 | (partial && mode == afs_flock_mode_openafs)) { | |
509 | no_server_lock = true; | |
510 | goto skip_server_lock; | |
ff8e210a | 511 | } |
e8d6c554 | 512 | |
e8d6c554 | 513 | spin_lock(&vnode->lock); |
0fafdc9f | 514 | list_add_tail(&fl->fl_u.afs.link, &vnode->pending_locks); |
e8d6c554 | 515 | |
cdfb26b4 DH |
516 | ret = -ENOENT; |
517 | if (vnode->lock_state == AFS_VNODE_LOCK_DELETED) | |
518 | goto error_unlock; | |
519 | ||
4be5975a DH |
520 | /* If we've already got a lock on the server then try to move to having |
521 | * the VFS grant the requested lock. Note that this means that other | |
522 | * clients may get starved out. | |
0fafdc9f | 523 | */ |
4be5975a DH |
524 | _debug("try %u", vnode->lock_state); |
525 | if (vnode->lock_state == AFS_VNODE_LOCK_GRANTED) { | |
526 | if (type == AFS_LOCK_READ) { | |
527 | _debug("instant readlock"); | |
528 | list_move_tail(&fl->fl_u.afs.link, &vnode->granted_locks); | |
529 | fl->fl_u.afs.state = AFS_LOCK_GRANTED; | |
530 | goto vnode_is_locked_u; | |
531 | } | |
e8d6c554 | 532 | |
4be5975a DH |
533 | if (vnode->lock_type == AFS_LOCK_WRITE) { |
534 | _debug("instant writelock"); | |
535 | list_move_tail(&fl->fl_u.afs.link, &vnode->granted_locks); | |
536 | fl->fl_u.afs.state = AFS_LOCK_GRANTED; | |
537 | goto vnode_is_locked_u; | |
538 | } | |
539 | } | |
e8d6c554 | 540 | |
6c6c1d63 DH |
541 | if (vnode->lock_state == AFS_VNODE_LOCK_NONE && |
542 | !(fl->fl_flags & FL_SLEEP)) { | |
543 | ret = -EAGAIN; | |
544 | if (type == AFS_LOCK_READ) { | |
545 | if (vnode->status.lock_count == -1) | |
546 | goto lock_is_contended; /* Write locked */ | |
547 | } else { | |
548 | if (vnode->status.lock_count != 0) | |
549 | goto lock_is_contended; /* Locked */ | |
550 | } | |
551 | } | |
552 | ||
0fafdc9f DH |
553 | if (vnode->lock_state != AFS_VNODE_LOCK_NONE) |
554 | goto need_to_wait; | |
e8d6c554 | 555 | |
4be5975a | 556 | try_to_lock: |
0fafdc9f DH |
557 | /* We don't have a lock on this vnode and we aren't currently waiting |
558 | * for one either, so ask the server for a lock. | |
559 | * | |
560 | * Note that we need to be careful if we get interrupted by a signal | |
561 | * after dispatching the request as we may still get the lock, even | |
562 | * though we don't wait for the reply (it's not too bad a problem - the | |
4be5975a | 563 | * lock will expire in 5 mins anyway). |
0fafdc9f | 564 | */ |
d4696601 | 565 | trace_afs_flock_ev(vnode, fl, afs_flock_try_to_lock, 0); |
0fafdc9f DH |
566 | vnode->lock_key = key_get(key); |
567 | vnode->lock_type = type; | |
4be5975a | 568 | afs_set_lock_state(vnode, AFS_VNODE_LOCK_SETTING); |
e8d6c554 DH |
569 | spin_unlock(&vnode->lock); |
570 | ||
0fafdc9f | 571 | ret = afs_set_lock(vnode, key, type); /* RPC */ |
e8d6c554 DH |
572 | |
573 | spin_lock(&vnode->lock); | |
0fafdc9f | 574 | switch (ret) { |
4be5975a DH |
575 | case -EKEYREJECTED: |
576 | case -EKEYEXPIRED: | |
577 | case -EKEYREVOKED: | |
578 | case -EPERM: | |
579 | case -EACCES: | |
580 | fl->fl_u.afs.state = ret; | |
d4696601 | 581 | trace_afs_flock_ev(vnode, fl, afs_flock_fail_perm, ret); |
4be5975a DH |
582 | list_del_init(&fl->fl_u.afs.link); |
583 | afs_next_locker(vnode, ret); | |
584 | goto error_unlock; | |
585 | ||
cdfb26b4 DH |
586 | case -ENOENT: |
587 | fl->fl_u.afs.state = ret; | |
588 | trace_afs_flock_ev(vnode, fl, afs_flock_fail_other, ret); | |
589 | list_del_init(&fl->fl_u.afs.link); | |
590 | afs_kill_lockers_enoent(vnode); | |
591 | goto error_unlock; | |
592 | ||
0fafdc9f | 593 | default: |
4be5975a | 594 | fl->fl_u.afs.state = ret; |
d4696601 | 595 | trace_afs_flock_ev(vnode, fl, afs_flock_fail_other, ret); |
4be5975a DH |
596 | list_del_init(&fl->fl_u.afs.link); |
597 | afs_next_locker(vnode, 0); | |
598 | goto error_unlock; | |
e8d6c554 | 599 | |
0fafdc9f DH |
600 | case -EWOULDBLOCK: |
601 | /* The server doesn't have a lock-waiting queue, so the client | |
602 | * will have to retry. The server will break the outstanding | |
603 | * callbacks on a file when a lock is released. | |
604 | */ | |
0fafdc9f DH |
605 | ASSERT(list_empty(&vnode->granted_locks)); |
606 | ASSERTCMP(vnode->pending_locks.next, ==, &fl->fl_u.afs.link); | |
4be5975a | 607 | goto lock_is_contended; |
0fafdc9f DH |
608 | |
609 | case 0: | |
4be5975a | 610 | afs_set_lock_state(vnode, AFS_VNODE_LOCK_GRANTED); |
d4696601 | 611 | trace_afs_flock_ev(vnode, fl, afs_flock_acquired, type); |
4be5975a DH |
612 | afs_grant_locks(vnode); |
613 | goto vnode_is_locked_u; | |
e8d6c554 | 614 | } |
e8d6c554 | 615 | |
4be5975a | 616 | vnode_is_locked_u: |
0fafdc9f | 617 | spin_unlock(&vnode->lock); |
4be5975a DH |
618 | vnode_is_locked: |
619 | /* the lock has been granted by the server... */ | |
620 | ASSERTCMP(fl->fl_u.afs.state, ==, AFS_LOCK_GRANTED); | |
0fafdc9f | 621 | |
6c6c1d63 | 622 | skip_server_lock: |
4be5975a | 623 | /* ... but the VFS still needs to distribute access on this client. */ |
d4696601 | 624 | trace_afs_flock_ev(vnode, fl, afs_flock_vfs_locking, 0); |
4be5975a | 625 | ret = locks_lock_file_wait(file, fl); |
d4696601 | 626 | trace_afs_flock_ev(vnode, fl, afs_flock_vfs_lock, ret); |
e8d6c554 DH |
627 | if (ret < 0) |
628 | goto vfs_rejected_lock; | |
e8d6c554 | 629 | |
0fafdc9f | 630 | /* Again, make sure we've got a callback on this file and, again, make |
e8d6c554 | 631 | * sure that our view of the data version is up to date (we ignore |
0fafdc9f DH |
632 | * errors incurred here and deal with the consequences elsewhere). |
633 | */ | |
d2ddc776 | 634 | afs_validate(vnode, key); |
0fafdc9f DH |
635 | _leave(" = 0"); |
636 | return 0; | |
e8d6c554 | 637 | |
4be5975a DH |
638 | lock_is_contended: |
639 | if (!(fl->fl_flags & FL_SLEEP)) { | |
640 | list_del_init(&fl->fl_u.afs.link); | |
641 | afs_next_locker(vnode, 0); | |
642 | ret = -EAGAIN; | |
643 | goto error_unlock; | |
644 | } | |
645 | ||
646 | afs_set_lock_state(vnode, AFS_VNODE_LOCK_WAITING_FOR_CB); | |
d4696601 | 647 | trace_afs_flock_ev(vnode, fl, afs_flock_would_block, ret); |
4be5975a DH |
648 | queue_delayed_work(afs_lock_manager, &vnode->lock_work, HZ * 5); |
649 | ||
0fafdc9f DH |
650 | need_to_wait: |
651 | /* We're going to have to wait. Either this client doesn't have a lock | |
652 | * on the server yet and we need to wait for a callback to occur, or | |
4be5975a DH |
653 | * the client does have a lock on the server, but it's shared and we |
654 | * need an exclusive lock. | |
0fafdc9f | 655 | */ |
4be5975a | 656 | spin_unlock(&vnode->lock); |
0fafdc9f | 657 | |
d4696601 | 658 | trace_afs_flock_ev(vnode, fl, afs_flock_waiting, 0); |
4be5975a DH |
659 | ret = wait_event_interruptible(fl->fl_wait, |
660 | fl->fl_u.afs.state != AFS_LOCK_PENDING); | |
d4696601 | 661 | trace_afs_flock_ev(vnode, fl, afs_flock_waited, ret); |
0fafdc9f | 662 | |
4be5975a | 663 | if (fl->fl_u.afs.state >= 0 && fl->fl_u.afs.state != AFS_LOCK_GRANTED) { |
0fafdc9f | 664 | spin_lock(&vnode->lock); |
0fafdc9f | 665 | |
4be5975a DH |
666 | switch (fl->fl_u.afs.state) { |
667 | case AFS_LOCK_YOUR_TRY: | |
668 | fl->fl_u.afs.state = AFS_LOCK_PENDING; | |
669 | goto try_to_lock; | |
670 | case AFS_LOCK_PENDING: | |
671 | if (ret > 0) { | |
672 | /* We need to retry the lock. We may not be | |
673 | * notified by the server if it just expired | |
674 | * rather than being released. | |
675 | */ | |
676 | ASSERTCMP(vnode->lock_state, ==, AFS_VNODE_LOCK_WAITING_FOR_CB); | |
677 | afs_set_lock_state(vnode, AFS_VNODE_LOCK_SETTING); | |
678 | fl->fl_u.afs.state = AFS_LOCK_PENDING; | |
679 | goto try_to_lock; | |
680 | } | |
681 | goto error_unlock; | |
682 | case AFS_LOCK_GRANTED: | |
683 | default: | |
684 | break; | |
685 | } | |
0fafdc9f | 686 | |
4be5975a DH |
687 | spin_unlock(&vnode->lock); |
688 | } | |
0fafdc9f | 689 | |
4be5975a DH |
690 | if (fl->fl_u.afs.state == AFS_LOCK_GRANTED) |
691 | goto vnode_is_locked; | |
692 | ret = fl->fl_u.afs.state; | |
693 | goto error; | |
e8d6c554 DH |
694 | |
695 | vfs_rejected_lock: | |
0fafdc9f DH |
696 | /* The VFS rejected the lock we just obtained, so we have to discard |
697 | * what we just got. We defer this to the lock manager work item to | |
698 | * deal with. | |
699 | */ | |
e8d6c554 | 700 | _debug("vfs refused %d", ret); |
6c6c1d63 DH |
701 | if (no_server_lock) |
702 | goto error; | |
0fafdc9f | 703 | spin_lock(&vnode->lock); |
e8d6c554 | 704 | list_del_init(&fl->fl_u.afs.link); |
4be5975a DH |
705 | afs_defer_unlock(vnode); |
706 | ||
707 | error_unlock: | |
708 | spin_unlock(&vnode->lock); | |
709 | error: | |
710 | _leave(" = %d", ret); | |
711 | return ret; | |
e8d6c554 DH |
712 | } |
713 | ||
714 | /* | |
715 | * unlock on a file on the server | |
716 | */ | |
717 | static int afs_do_unlk(struct file *file, struct file_lock *fl) | |
718 | { | |
0fafdc9f | 719 | struct afs_vnode *vnode = AFS_FS_I(locks_inode(file)); |
e8d6c554 DH |
720 | int ret; |
721 | ||
3b6492df | 722 | _enter("{%llx:%llu},%u", vnode->fid.vid, vnode->fid.vnode, fl->fl_type); |
e8d6c554 | 723 | |
d4696601 DH |
724 | trace_afs_flock_op(vnode, fl, afs_flock_op_unlock); |
725 | ||
0fafdc9f DH |
726 | /* Flush all pending writes before doing anything with locks. */ |
727 | vfs_fsync(file, 0); | |
728 | ||
4be5975a | 729 | ret = locks_lock_file_wait(file, fl); |
0fafdc9f DH |
730 | _leave(" = %d [%u]", ret, vnode->lock_state); |
731 | return ret; | |
e8d6c554 DH |
732 | } |
733 | ||
734 | /* | |
735 | * return information about a lock we currently hold, if indeed we hold one | |
736 | */ | |
737 | static int afs_do_getlk(struct file *file, struct file_lock *fl) | |
738 | { | |
0fafdc9f | 739 | struct afs_vnode *vnode = AFS_FS_I(locks_inode(file)); |
215804a9 | 740 | struct key *key = afs_file_key(file); |
e8d6c554 DH |
741 | int ret, lock_count; |
742 | ||
743 | _enter(""); | |
744 | ||
cdfb26b4 DH |
745 | if (vnode->lock_state == AFS_VNODE_LOCK_DELETED) |
746 | return -ENOENT; | |
747 | ||
e8d6c554 DH |
748 | fl->fl_type = F_UNLCK; |
749 | ||
e8d6c554 | 750 | /* check local lock records first */ |
275afcac AM |
751 | posix_test_lock(file, fl); |
752 | if (fl->fl_type == F_UNLCK) { | |
e8d6c554 | 753 | /* no local locks; consult the server */ |
a58823ac | 754 | ret = afs_fetch_status(vnode, key, false, NULL); |
e8d6c554 DH |
755 | if (ret < 0) |
756 | goto error; | |
0fafdc9f DH |
757 | |
758 | lock_count = READ_ONCE(vnode->status.lock_count); | |
68ce801f DH |
759 | if (lock_count != 0) { |
760 | if (lock_count > 0) | |
761 | fl->fl_type = F_RDLCK; | |
762 | else | |
763 | fl->fl_type = F_WRLCK; | |
764 | fl->fl_start = 0; | |
765 | fl->fl_end = OFFSET_MAX; | |
766 | fl->fl_pid = 0; | |
767 | } | |
e8d6c554 DH |
768 | } |
769 | ||
0fafdc9f | 770 | ret = 0; |
e8d6c554 | 771 | error: |
e8d6c554 DH |
772 | _leave(" = %d [%hd]", ret, fl->fl_type); |
773 | return ret; | |
774 | } | |
775 | ||
776 | /* | |
777 | * manage POSIX locks on a file | |
778 | */ | |
779 | int afs_lock(struct file *file, int cmd, struct file_lock *fl) | |
780 | { | |
0fafdc9f | 781 | struct afs_vnode *vnode = AFS_FS_I(locks_inode(file)); |
d4696601 DH |
782 | enum afs_flock_operation op; |
783 | int ret; | |
e8d6c554 | 784 | |
3b6492df | 785 | _enter("{%llx:%llu},%d,{t=%x,fl=%x,r=%Ld:%Ld}", |
e8d6c554 DH |
786 | vnode->fid.vid, vnode->fid.vnode, cmd, |
787 | fl->fl_type, fl->fl_flags, | |
788 | (long long) fl->fl_start, (long long) fl->fl_end); | |
789 | ||
790 | /* AFS doesn't support mandatory locks */ | |
fc5846e5 | 791 | if (__mandatory_lock(&vnode->vfs_inode) && fl->fl_type != F_UNLCK) |
e8d6c554 DH |
792 | return -ENOLCK; |
793 | ||
794 | if (IS_GETLK(cmd)) | |
795 | return afs_do_getlk(file, fl); | |
d4696601 DH |
796 | |
797 | fl->fl_u.afs.debug_id = atomic_inc_return(&afs_file_lock_debug_id); | |
798 | trace_afs_flock_op(vnode, fl, afs_flock_op_lock); | |
799 | ||
e8d6c554 | 800 | if (fl->fl_type == F_UNLCK) |
d4696601 DH |
801 | ret = afs_do_unlk(file, fl); |
802 | else | |
803 | ret = afs_do_setlk(file, fl); | |
804 | ||
805 | switch (ret) { | |
806 | case 0: op = afs_flock_op_return_ok; break; | |
807 | case -EAGAIN: op = afs_flock_op_return_eagain; break; | |
808 | case -EDEADLK: op = afs_flock_op_return_edeadlk; break; | |
809 | default: op = afs_flock_op_return_error; break; | |
810 | } | |
811 | trace_afs_flock_op(vnode, fl, op); | |
812 | return ret; | |
e8d6c554 DH |
813 | } |
814 | ||
815 | /* | |
816 | * manage FLOCK locks on a file | |
817 | */ | |
818 | int afs_flock(struct file *file, int cmd, struct file_lock *fl) | |
819 | { | |
0fafdc9f | 820 | struct afs_vnode *vnode = AFS_FS_I(locks_inode(file)); |
d4696601 DH |
821 | enum afs_flock_operation op; |
822 | int ret; | |
e8d6c554 | 823 | |
3b6492df | 824 | _enter("{%llx:%llu},%d,{t=%x,fl=%x}", |
e8d6c554 DH |
825 | vnode->fid.vid, vnode->fid.vnode, cmd, |
826 | fl->fl_type, fl->fl_flags); | |
827 | ||
828 | /* | |
829 | * No BSD flocks over NFS allowed. | |
830 | * Note: we could try to fake a POSIX lock request here by | |
831 | * using ((u32) filp | 0x80000000) or some such as the pid. | |
832 | * Not sure whether that would be unique, though, or whether | |
833 | * that would break in other places. | |
834 | */ | |
835 | if (!(fl->fl_flags & FL_FLOCK)) | |
836 | return -ENOLCK; | |
837 | ||
d4696601 DH |
838 | fl->fl_u.afs.debug_id = atomic_inc_return(&afs_file_lock_debug_id); |
839 | trace_afs_flock_op(vnode, fl, afs_flock_op_flock); | |
840 | ||
e8d6c554 | 841 | /* we're simulating flock() locks using posix locks on the server */ |
e8d6c554 | 842 | if (fl->fl_type == F_UNLCK) |
d4696601 DH |
843 | ret = afs_do_unlk(file, fl); |
844 | else | |
845 | ret = afs_do_setlk(file, fl); | |
846 | ||
847 | switch (ret) { | |
848 | case 0: op = afs_flock_op_return_ok; break; | |
849 | case -EAGAIN: op = afs_flock_op_return_eagain; break; | |
850 | case -EDEADLK: op = afs_flock_op_return_edeadlk; break; | |
851 | default: op = afs_flock_op_return_error; break; | |
852 | } | |
853 | trace_afs_flock_op(vnode, fl, op); | |
854 | return ret; | |
e8d6c554 DH |
855 | } |
856 | ||
857 | /* | |
858 | * the POSIX lock management core VFS code copies the lock record and adds the | |
859 | * copy into its own list, so we need to add that copy to the vnode's lock | |
860 | * queue in the same place as the original (which will be deleted shortly | |
861 | * after) | |
862 | */ | |
863 | static void afs_fl_copy_lock(struct file_lock *new, struct file_lock *fl) | |
864 | { | |
0fafdc9f DH |
865 | struct afs_vnode *vnode = AFS_FS_I(locks_inode(fl->fl_file)); |
866 | ||
e8d6c554 DH |
867 | _enter(""); |
868 | ||
d4696601 DH |
869 | new->fl_u.afs.debug_id = atomic_inc_return(&afs_file_lock_debug_id); |
870 | ||
0fafdc9f | 871 | spin_lock(&vnode->lock); |
d4696601 | 872 | trace_afs_flock_op(vnode, new, afs_flock_op_copy_lock); |
e8d6c554 | 873 | list_add(&new->fl_u.afs.link, &fl->fl_u.afs.link); |
0fafdc9f | 874 | spin_unlock(&vnode->lock); |
e8d6c554 DH |
875 | } |
876 | ||
877 | /* | |
878 | * need to remove this lock from the vnode queue when it's removed from the | |
879 | * VFS's list | |
880 | */ | |
881 | static void afs_fl_release_private(struct file_lock *fl) | |
882 | { | |
0fafdc9f DH |
883 | struct afs_vnode *vnode = AFS_FS_I(locks_inode(fl->fl_file)); |
884 | ||
e8d6c554 DH |
885 | _enter(""); |
886 | ||
0fafdc9f | 887 | spin_lock(&vnode->lock); |
4be5975a | 888 | |
d4696601 | 889 | trace_afs_flock_op(vnode, fl, afs_flock_op_release_lock); |
4be5975a DH |
890 | list_del_init(&fl->fl_u.afs.link); |
891 | if (list_empty(&vnode->granted_locks)) | |
892 | afs_defer_unlock(vnode); | |
893 | ||
0fafdc9f DH |
894 | _debug("state %u for %p", vnode->lock_state, vnode); |
895 | spin_unlock(&vnode->lock); | |
e8d6c554 | 896 | } |