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1 | /* |
2 | * linux/fs/lockd/clntproc.c |
3 | * |
4 | * RPC procedures for the client side NLM implementation |
5 | * |
6 | * Copyright (C) 1996, Olaf Kirch <okir@monad.swb.de> |
7 | */ |
8 | |
9 | #include <linux/module.h> |
10 | #include <linux/smp_lock.h> |
11 | #include <linux/slab.h> |
12 | #include <linux/types.h> |
13 | #include <linux/errno.h> |
14 | #include <linux/fs.h> |
15 | #include <linux/nfs_fs.h> |
16 | #include <linux/utsname.h> |
17 | #include <linux/freezer.h> |
18 | #include <linux/sunrpc/clnt.h> |
19 | #include <linux/sunrpc/svc.h> |
20 | #include <linux/lockd/lockd.h> |
21 | |
22 | #define NLMDBG_FACILITY NLMDBG_CLIENT |
23 | #define NLMCLNT_GRACE_WAIT (5*HZ) |
24 | #define NLMCLNT_POLL_TIMEOUT (30*HZ) |
25 | #define NLMCLNT_MAX_RETRIES 3 |
26 | |
27 | static int nlmclnt_test(struct nlm_rqst *, struct file_lock *); |
28 | static int nlmclnt_lock(struct nlm_rqst *, struct file_lock *); |
29 | static int nlmclnt_unlock(struct nlm_rqst *, struct file_lock *); |
30 | static int nlm_stat_to_errno(__be32 stat); |
31 | static void nlmclnt_locks_init_private(struct file_lock *fl, struct nlm_host *host); |
32 | static int nlmclnt_cancel(struct nlm_host *, int , struct file_lock *); |
33 | |
34 | static const struct rpc_call_ops nlmclnt_unlock_ops; |
35 | static const struct rpc_call_ops nlmclnt_cancel_ops; |
36 | |
37 | /* |
38 | * Cookie counter for NLM requests |
39 | */ |
40 | static atomic_t nlm_cookie = ATOMIC_INIT(0x1234); |
41 | |
42 | void nlmclnt_next_cookie(struct nlm_cookie *c) |
43 | { |
44 | u32 cookie = atomic_inc_return(&nlm_cookie); |
45 | |
46 | memcpy(c->data, &cookie, 4); |
47 | c->len=4; |
48 | } |
49 | |
50 | static struct nlm_lockowner *nlm_get_lockowner(struct nlm_lockowner *lockowner) |
51 | { |
52 | atomic_inc(&lockowner->count); |
53 | return lockowner; |
54 | } |
55 | |
56 | static void nlm_put_lockowner(struct nlm_lockowner *lockowner) |
57 | { |
58 | if (!atomic_dec_and_lock(&lockowner->count, &lockowner->host->h_lock)) |
59 | return; |
60 | list_del(&lockowner->list); |
61 | spin_unlock(&lockowner->host->h_lock); |
62 | nlm_release_host(lockowner->host); |
63 | kfree(lockowner); |
64 | } |
65 | |
66 | static inline int nlm_pidbusy(struct nlm_host *host, uint32_t pid) |
67 | { |
68 | struct nlm_lockowner *lockowner; |
69 | list_for_each_entry(lockowner, &host->h_lockowners, list) { |
70 | if (lockowner->pid == pid) |
71 | return -EBUSY; |
72 | } |
73 | return 0; |
74 | } |
75 | |
76 | static inline uint32_t __nlm_alloc_pid(struct nlm_host *host) |
77 | { |
78 | uint32_t res; |
79 | do { |
80 | res = host->h_pidcount++; |
81 | } while (nlm_pidbusy(host, res) < 0); |
82 | return res; |
83 | } |
84 | |
85 | static struct nlm_lockowner *__nlm_find_lockowner(struct nlm_host *host, fl_owner_t owner) |
86 | { |
87 | struct nlm_lockowner *lockowner; |
88 | list_for_each_entry(lockowner, &host->h_lockowners, list) { |
89 | if (lockowner->owner != owner) |
90 | continue; |
91 | return nlm_get_lockowner(lockowner); |
92 | } |
93 | return NULL; |
94 | } |
95 | |
96 | static struct nlm_lockowner *nlm_find_lockowner(struct nlm_host *host, fl_owner_t owner) |
97 | { |
98 | struct nlm_lockowner *res, *new = NULL; |
99 | |
100 | spin_lock(&host->h_lock); |
101 | res = __nlm_find_lockowner(host, owner); |
102 | if (res == NULL) { |
103 | spin_unlock(&host->h_lock); |
104 | new = kmalloc(sizeof(*new), GFP_KERNEL); |
105 | spin_lock(&host->h_lock); |
106 | res = __nlm_find_lockowner(host, owner); |
107 | if (res == NULL && new != NULL) { |
108 | res = new; |
109 | atomic_set(&new->count, 1); |
110 | new->owner = owner; |
111 | new->pid = __nlm_alloc_pid(host); |
112 | new->host = nlm_get_host(host); |
113 | list_add(&new->list, &host->h_lockowners); |
114 | new = NULL; |
115 | } |
116 | } |
117 | spin_unlock(&host->h_lock); |
118 | kfree(new); |
119 | return res; |
120 | } |
121 | |
122 | /* |
123 | * Initialize arguments for TEST/LOCK/UNLOCK/CANCEL calls |
124 | */ |
125 | static void nlmclnt_setlockargs(struct nlm_rqst *req, struct file_lock *fl) |
126 | { |
127 | struct nlm_args *argp = &req->a_args; |
128 | struct nlm_lock *lock = &argp->lock; |
129 | |
130 | nlmclnt_next_cookie(&argp->cookie); |
131 | memcpy(&lock->fh, NFS_FH(fl->fl_file->f_path.dentry->d_inode), sizeof(struct nfs_fh)); |
132 | lock->caller = utsname()->nodename; |
133 | lock->oh.data = req->a_owner; |
134 | lock->oh.len = snprintf(req->a_owner, sizeof(req->a_owner), "%u@%s", |
135 | (unsigned int)fl->fl_u.nfs_fl.owner->pid, |
136 | utsname()->nodename); |
137 | lock->svid = fl->fl_u.nfs_fl.owner->pid; |
138 | lock->fl.fl_start = fl->fl_start; |
139 | lock->fl.fl_end = fl->fl_end; |
140 | lock->fl.fl_type = fl->fl_type; |
141 | } |
142 | |
143 | static void nlmclnt_release_lockargs(struct nlm_rqst *req) |
144 | { |
145 | BUG_ON(req->a_args.lock.fl.fl_ops != NULL); |
146 | } |
147 | |
148 | /** |
149 | * nlmclnt_proc - Perform a single client-side lock request |
150 | * @host: address of a valid nlm_host context representing the NLM server |
151 | * @cmd: fcntl-style file lock operation to perform |
152 | * @fl: address of arguments for the lock operation |
153 | * |
154 | */ |
155 | int nlmclnt_proc(struct nlm_host *host, int cmd, struct file_lock *fl) |
156 | { |
157 | struct nlm_rqst *call; |
158 | int status; |
159 | |
160 | nlm_get_host(host); |
161 | call = nlm_alloc_call(host); |
162 | if (call == NULL) |
163 | return -ENOMEM; |
164 | |
165 | nlmclnt_locks_init_private(fl, host); |
166 | /* Set up the argument struct */ |
167 | nlmclnt_setlockargs(call, fl); |
168 | |
169 | lock_kernel(); |
170 | if (IS_SETLK(cmd) || IS_SETLKW(cmd)) { |
171 | if (fl->fl_type != F_UNLCK) { |
172 | call->a_args.block = IS_SETLKW(cmd) ? 1 : 0; |
173 | status = nlmclnt_lock(call, fl); |
174 | } else |
175 | status = nlmclnt_unlock(call, fl); |
176 | } else if (IS_GETLK(cmd)) |
177 | status = nlmclnt_test(call, fl); |
178 | else |
179 | status = -EINVAL; |
180 | |
181 | fl->fl_ops->fl_release_private(fl); |
182 | fl->fl_ops = NULL; |
183 | unlock_kernel(); |
184 | |
185 | dprintk("lockd: clnt proc returns %d\n", status); |
186 | return status; |
187 | } |
188 | EXPORT_SYMBOL_GPL(nlmclnt_proc); |
189 | |
190 | /* |
191 | * Allocate an NLM RPC call struct |
192 | * |
193 | * Note: the caller must hold a reference to host. In case of failure, |
194 | * this reference will be released. |
195 | */ |
196 | struct nlm_rqst *nlm_alloc_call(struct nlm_host *host) |
197 | { |
198 | struct nlm_rqst *call; |
199 | |
200 | for(;;) { |
201 | call = kzalloc(sizeof(*call), GFP_KERNEL); |
202 | if (call != NULL) { |
203 | atomic_set(&call->a_count, 1); |
204 | locks_init_lock(&call->a_args.lock.fl); |
205 | locks_init_lock(&call->a_res.lock.fl); |
206 | call->a_host = host; |
207 | return call; |
208 | } |
209 | if (signalled()) |
210 | break; |
211 | printk("nlm_alloc_call: failed, waiting for memory\n"); |
212 | schedule_timeout_interruptible(5*HZ); |
213 | } |
214 | nlm_release_host(host); |
215 | return NULL; |
216 | } |
217 | |
218 | void nlm_release_call(struct nlm_rqst *call) |
219 | { |
220 | if (!atomic_dec_and_test(&call->a_count)) |
221 | return; |
222 | nlm_release_host(call->a_host); |
223 | nlmclnt_release_lockargs(call); |
224 | kfree(call); |
225 | } |
226 | |
227 | static void nlmclnt_rpc_release(void *data) |
228 | { |
229 | lock_kernel(); |
230 | nlm_release_call(data); |
231 | unlock_kernel(); |
232 | } |
233 | |
234 | static int nlm_wait_on_grace(wait_queue_head_t *queue) |
235 | { |
236 | DEFINE_WAIT(wait); |
237 | int status = -EINTR; |
238 | |
239 | prepare_to_wait(queue, &wait, TASK_INTERRUPTIBLE); |
240 | if (!signalled ()) { |
241 | schedule_timeout(NLMCLNT_GRACE_WAIT); |
242 | try_to_freeze(); |
243 | if (!signalled ()) |
244 | status = 0; |
245 | } |
246 | finish_wait(queue, &wait); |
247 | return status; |
248 | } |
249 | |
250 | /* |
251 | * Generic NLM call |
252 | */ |
253 | static int |
254 | nlmclnt_call(struct rpc_cred *cred, struct nlm_rqst *req, u32 proc) |
255 | { |
256 | struct nlm_host *host = req->a_host; |
257 | struct rpc_clnt *clnt; |
258 | struct nlm_args *argp = &req->a_args; |
259 | struct nlm_res *resp = &req->a_res; |
260 | struct rpc_message msg = { |
261 | .rpc_argp = argp, |
262 | .rpc_resp = resp, |
263 | .rpc_cred = cred, |
264 | }; |
265 | int status; |
266 | |
267 | dprintk("lockd: call procedure %d on %s\n", |
268 | (int)proc, host->h_name); |
269 | |
270 | do { |
271 | if (host->h_reclaiming && !argp->reclaim) |
272 | goto in_grace_period; |
273 | |
274 | /* If we have no RPC client yet, create one. */ |
275 | if ((clnt = nlm_bind_host(host)) == NULL) |
276 | return -ENOLCK; |
277 | msg.rpc_proc = &clnt->cl_procinfo[proc]; |
278 | |
279 | /* Perform the RPC call. If an error occurs, try again */ |
280 | if ((status = rpc_call_sync(clnt, &msg, 0)) < 0) { |
281 | dprintk("lockd: rpc_call returned error %d\n", -status); |
282 | switch (status) { |
283 | case -EPROTONOSUPPORT: |
284 | status = -EINVAL; |
285 | break; |
286 | case -ECONNREFUSED: |
287 | case -ETIMEDOUT: |
288 | case -ENOTCONN: |
289 | nlm_rebind_host(host); |
290 | status = -EAGAIN; |
291 | break; |
292 | case -ERESTARTSYS: |
293 | return signalled () ? -EINTR : status; |
294 | default: |
295 | break; |
296 | } |
297 | break; |
298 | } else |
299 | if (resp->status == nlm_lck_denied_grace_period) { |
300 | dprintk("lockd: server in grace period\n"); |
301 | if (argp->reclaim) { |
302 | printk(KERN_WARNING |
303 | "lockd: spurious grace period reject?!\n"); |
304 | return -ENOLCK; |
305 | } |
306 | } else { |
307 | if (!argp->reclaim) { |
308 | /* We appear to be out of the grace period */ |
309 | wake_up_all(&host->h_gracewait); |
310 | } |
311 | dprintk("lockd: server returns status %d\n", resp->status); |
312 | return 0; /* Okay, call complete */ |
313 | } |
314 | |
315 | in_grace_period: |
316 | /* |
317 | * The server has rebooted and appears to be in the grace |
318 | * period during which locks are only allowed to be |
319 | * reclaimed. |
320 | * We can only back off and try again later. |
321 | */ |
322 | status = nlm_wait_on_grace(&host->h_gracewait); |
323 | } while (status == 0); |
324 | |
325 | return status; |
326 | } |
327 | |
328 | /* |
329 | * Generic NLM call, async version. |
330 | */ |
331 | static struct rpc_task *__nlm_async_call(struct nlm_rqst *req, u32 proc, struct rpc_message *msg, const struct rpc_call_ops *tk_ops) |
332 | { |
333 | struct nlm_host *host = req->a_host; |
334 | struct rpc_clnt *clnt; |
335 | struct rpc_task_setup task_setup_data = { |
336 | .rpc_message = msg, |
337 | .callback_ops = tk_ops, |
338 | .callback_data = req, |
339 | .flags = RPC_TASK_ASYNC, |
340 | }; |
341 | |
342 | dprintk("lockd: call procedure %d on %s (async)\n", |
343 | (int)proc, host->h_name); |
344 | |
345 | /* If we have no RPC client yet, create one. */ |
346 | clnt = nlm_bind_host(host); |
347 | if (clnt == NULL) |
348 | goto out_err; |
349 | msg->rpc_proc = &clnt->cl_procinfo[proc]; |
350 | task_setup_data.rpc_client = clnt; |
351 | |
352 | /* bootstrap and kick off the async RPC call */ |
353 | return rpc_run_task(&task_setup_data); |
354 | out_err: |
355 | tk_ops->rpc_release(req); |
356 | return ERR_PTR(-ENOLCK); |
357 | } |
358 | |
359 | static int nlm_do_async_call(struct nlm_rqst *req, u32 proc, struct rpc_message *msg, const struct rpc_call_ops *tk_ops) |
360 | { |
361 | struct rpc_task *task; |
362 | |
363 | task = __nlm_async_call(req, proc, msg, tk_ops); |
364 | if (IS_ERR(task)) |
365 | return PTR_ERR(task); |
366 | rpc_put_task(task); |
367 | return 0; |
368 | } |
369 | |
370 | /* |
371 | * NLM asynchronous call. |
372 | */ |
373 | int nlm_async_call(struct nlm_rqst *req, u32 proc, const struct rpc_call_ops *tk_ops) |
374 | { |
375 | struct rpc_message msg = { |
376 | .rpc_argp = &req->a_args, |
377 | .rpc_resp = &req->a_res, |
378 | }; |
379 | return nlm_do_async_call(req, proc, &msg, tk_ops); |
380 | } |
381 | |
382 | int nlm_async_reply(struct nlm_rqst *req, u32 proc, const struct rpc_call_ops *tk_ops) |
383 | { |
384 | struct rpc_message msg = { |
385 | .rpc_argp = &req->a_res, |
386 | }; |
387 | return nlm_do_async_call(req, proc, &msg, tk_ops); |
388 | } |
389 | |
390 | /* |
391 | * NLM client asynchronous call. |
392 | * |
393 | * Note that although the calls are asynchronous, and are therefore |
394 | * guaranteed to complete, we still always attempt to wait for |
395 | * completion in order to be able to correctly track the lock |
396 | * state. |
397 | */ |
398 | static int nlmclnt_async_call(struct rpc_cred *cred, struct nlm_rqst *req, u32 proc, const struct rpc_call_ops *tk_ops) |
399 | { |
400 | struct rpc_message msg = { |
401 | .rpc_argp = &req->a_args, |
402 | .rpc_resp = &req->a_res, |
403 | .rpc_cred = cred, |
404 | }; |
405 | struct rpc_task *task; |
406 | int err; |
407 | |
408 | task = __nlm_async_call(req, proc, &msg, tk_ops); |
409 | if (IS_ERR(task)) |
410 | return PTR_ERR(task); |
411 | err = rpc_wait_for_completion_task(task); |
412 | rpc_put_task(task); |
413 | return err; |
414 | } |
415 | |
416 | /* |
417 | * TEST for the presence of a conflicting lock |
418 | */ |
419 | static int |
420 | nlmclnt_test(struct nlm_rqst *req, struct file_lock *fl) |
421 | { |
422 | int status; |
423 | |
424 | status = nlmclnt_call(nfs_file_cred(fl->fl_file), req, NLMPROC_TEST); |
425 | if (status < 0) |
426 | goto out; |
427 | |
428 | switch (req->a_res.status) { |
429 | case nlm_granted: |
430 | fl->fl_type = F_UNLCK; |
431 | break; |
432 | case nlm_lck_denied: |
433 | /* |
434 | * Report the conflicting lock back to the application. |
435 | */ |
436 | fl->fl_start = req->a_res.lock.fl.fl_start; |
437 | fl->fl_end = req->a_res.lock.fl.fl_end; |
438 | fl->fl_type = req->a_res.lock.fl.fl_type; |
439 | fl->fl_pid = 0; |
440 | break; |
441 | default: |
442 | status = nlm_stat_to_errno(req->a_res.status); |
443 | } |
444 | out: |
445 | nlm_release_call(req); |
446 | return status; |
447 | } |
448 | |
449 | static void nlmclnt_locks_copy_lock(struct file_lock *new, struct file_lock *fl) |
450 | { |
451 | new->fl_u.nfs_fl.state = fl->fl_u.nfs_fl.state; |
452 | new->fl_u.nfs_fl.owner = nlm_get_lockowner(fl->fl_u.nfs_fl.owner); |
453 | list_add_tail(&new->fl_u.nfs_fl.list, &fl->fl_u.nfs_fl.owner->host->h_granted); |
454 | } |
455 | |
456 | static void nlmclnt_locks_release_private(struct file_lock *fl) |
457 | { |
458 | list_del(&fl->fl_u.nfs_fl.list); |
459 | nlm_put_lockowner(fl->fl_u.nfs_fl.owner); |
460 | } |
461 | |
462 | static const struct file_lock_operations nlmclnt_lock_ops = { |
463 | .fl_copy_lock = nlmclnt_locks_copy_lock, |
464 | .fl_release_private = nlmclnt_locks_release_private, |
465 | }; |
466 | |
467 | static void nlmclnt_locks_init_private(struct file_lock *fl, struct nlm_host *host) |
468 | { |
469 | BUG_ON(fl->fl_ops != NULL); |
470 | fl->fl_u.nfs_fl.state = 0; |
471 | fl->fl_u.nfs_fl.owner = nlm_find_lockowner(host, fl->fl_owner); |
472 | INIT_LIST_HEAD(&fl->fl_u.nfs_fl.list); |
473 | fl->fl_ops = &nlmclnt_lock_ops; |
474 | } |
475 | |
476 | static int do_vfs_lock(struct file_lock *fl) |
477 | { |
478 | int res = 0; |
479 | switch (fl->fl_flags & (FL_POSIX|FL_FLOCK)) { |
480 | case FL_POSIX: |
481 | res = posix_lock_file_wait(fl->fl_file, fl); |
482 | break; |
483 | case FL_FLOCK: |
484 | res = flock_lock_file_wait(fl->fl_file, fl); |
485 | break; |
486 | default: |
487 | BUG(); |
488 | } |
489 | return res; |
490 | } |
491 | |
492 | /* |
493 | * LOCK: Try to create a lock |
494 | * |
495 | * Programmer Harassment Alert |
496 | * |
497 | * When given a blocking lock request in a sync RPC call, the HPUX lockd |
498 | * will faithfully return LCK_BLOCKED but never cares to notify us when |
499 | * the lock could be granted. This way, our local process could hang |
500 | * around forever waiting for the callback. |
501 | * |
502 | * Solution A: Implement busy-waiting |
503 | * Solution B: Use the async version of the call (NLM_LOCK_{MSG,RES}) |
504 | * |
505 | * For now I am implementing solution A, because I hate the idea of |
506 | * re-implementing lockd for a third time in two months. The async |
507 | * calls shouldn't be too hard to do, however. |
508 | * |
509 | * This is one of the lovely things about standards in the NFS area: |
510 | * they're so soft and squishy you can't really blame HP for doing this. |
511 | */ |
512 | static int |
513 | nlmclnt_lock(struct nlm_rqst *req, struct file_lock *fl) |
514 | { |
515 | struct rpc_cred *cred = nfs_file_cred(fl->fl_file); |
516 | struct nlm_host *host = req->a_host; |
517 | struct nlm_res *resp = &req->a_res; |
518 | struct nlm_wait *block = NULL; |
519 | unsigned char fl_flags = fl->fl_flags; |
520 | unsigned char fl_type; |
521 | int status = -ENOLCK; |
522 | |
523 | if (nsm_monitor(host) < 0) |
524 | goto out; |
525 | req->a_args.state = nsm_local_state; |
526 | |
527 | fl->fl_flags |= FL_ACCESS; |
528 | status = do_vfs_lock(fl); |
529 | fl->fl_flags = fl_flags; |
530 | if (status < 0) |
531 | goto out; |
532 | |
533 | block = nlmclnt_prepare_block(host, fl); |
534 | again: |
535 | /* |
536 | * Initialise resp->status to a valid non-zero value, |
537 | * since 0 == nlm_lck_granted |
538 | */ |
539 | resp->status = nlm_lck_blocked; |
540 | for(;;) { |
541 | /* Reboot protection */ |
542 | fl->fl_u.nfs_fl.state = host->h_state; |
543 | status = nlmclnt_call(cred, req, NLMPROC_LOCK); |
544 | if (status < 0) |
545 | break; |
546 | /* Did a reclaimer thread notify us of a server reboot? */ |
547 | if (resp->status == nlm_lck_denied_grace_period) |
548 | continue; |
549 | if (resp->status != nlm_lck_blocked) |
550 | break; |
551 | /* Wait on an NLM blocking lock */ |
552 | status = nlmclnt_block(block, req, NLMCLNT_POLL_TIMEOUT); |
553 | if (status < 0) |
554 | break; |
555 | if (resp->status != nlm_lck_blocked) |
556 | break; |
557 | } |
558 | |
559 | /* if we were interrupted while blocking, then cancel the lock request |
560 | * and exit |
561 | */ |
562 | if (resp->status == nlm_lck_blocked) { |
563 | if (!req->a_args.block) |
564 | goto out_unlock; |
565 | if (nlmclnt_cancel(host, req->a_args.block, fl) == 0) |
566 | goto out_unblock; |
567 | } |
568 | |
569 | if (resp->status == nlm_granted) { |
570 | down_read(&host->h_rwsem); |
571 | /* Check whether or not the server has rebooted */ |
572 | if (fl->fl_u.nfs_fl.state != host->h_state) { |
573 | up_read(&host->h_rwsem); |
574 | goto again; |
575 | } |
576 | /* Ensure the resulting lock will get added to granted list */ |
577 | fl->fl_flags |= FL_SLEEP; |
578 | if (do_vfs_lock(fl) < 0) |
579 | printk(KERN_WARNING "%s: VFS is out of sync with lock manager!\n", __func__); |
580 | up_read(&host->h_rwsem); |
581 | fl->fl_flags = fl_flags; |
582 | status = 0; |
583 | } |
584 | if (status < 0) |
585 | goto out_unlock; |
586 | /* |
587 | * EAGAIN doesn't make sense for sleeping locks, and in some |
588 | * cases NLM_LCK_DENIED is returned for a permanent error. So |
589 | * turn it into an ENOLCK. |
590 | */ |
591 | if (resp->status == nlm_lck_denied && (fl_flags & FL_SLEEP)) |
592 | status = -ENOLCK; |
593 | else |
594 | status = nlm_stat_to_errno(resp->status); |
595 | out_unblock: |
596 | nlmclnt_finish_block(block); |
597 | out: |
598 | nlm_release_call(req); |
599 | return status; |
600 | out_unlock: |
601 | /* Fatal error: ensure that we remove the lock altogether */ |
602 | dprintk("lockd: lock attempt ended in fatal error.\n" |
603 | " Attempting to unlock.\n"); |
604 | nlmclnt_finish_block(block); |
605 | fl_type = fl->fl_type; |
606 | fl->fl_type = F_UNLCK; |
607 | down_read(&host->h_rwsem); |
608 | do_vfs_lock(fl); |
609 | up_read(&host->h_rwsem); |
610 | fl->fl_type = fl_type; |
611 | fl->fl_flags = fl_flags; |
612 | nlmclnt_async_call(cred, req, NLMPROC_UNLOCK, &nlmclnt_unlock_ops); |
613 | return status; |
614 | } |
615 | |
616 | /* |
617 | * RECLAIM: Try to reclaim a lock |
618 | */ |
619 | int |
620 | nlmclnt_reclaim(struct nlm_host *host, struct file_lock *fl) |
621 | { |
622 | struct nlm_rqst reqst, *req; |
623 | int status; |
624 | |
625 | req = &reqst; |
626 | memset(req, 0, sizeof(*req)); |
627 | locks_init_lock(&req->a_args.lock.fl); |
628 | locks_init_lock(&req->a_res.lock.fl); |
629 | req->a_host = host; |
630 | req->a_flags = 0; |
631 | |
632 | /* Set up the argument struct */ |
633 | nlmclnt_setlockargs(req, fl); |
634 | req->a_args.reclaim = 1; |
635 | |
636 | status = nlmclnt_call(nfs_file_cred(fl->fl_file), req, NLMPROC_LOCK); |
637 | if (status >= 0 && req->a_res.status == nlm_granted) |
638 | return 0; |
639 | |
640 | printk(KERN_WARNING "lockd: failed to reclaim lock for pid %d " |
641 | "(errno %d, status %d)\n", fl->fl_pid, |
642 | status, ntohl(req->a_res.status)); |
643 | |
644 | /* |
645 | * FIXME: This is a serious failure. We can |
646 | * |
647 | * a. Ignore the problem |
648 | * b. Send the owning process some signal (Linux doesn't have |
649 | * SIGLOST, though...) |
650 | * c. Retry the operation |
651 | * |
652 | * Until someone comes up with a simple implementation |
653 | * for b or c, I'll choose option a. |
654 | */ |
655 | |
656 | return -ENOLCK; |
657 | } |
658 | |
659 | /* |
660 | * UNLOCK: remove an existing lock |
661 | */ |
662 | static int |
663 | nlmclnt_unlock(struct nlm_rqst *req, struct file_lock *fl) |
664 | { |
665 | struct nlm_host *host = req->a_host; |
666 | struct nlm_res *resp = &req->a_res; |
667 | int status; |
668 | unsigned char fl_flags = fl->fl_flags; |
669 | |
670 | /* |
671 | * Note: the server is supposed to either grant us the unlock |
672 | * request, or to deny it with NLM_LCK_DENIED_GRACE_PERIOD. In either |
673 | * case, we want to unlock. |
674 | */ |
675 | fl->fl_flags |= FL_EXISTS; |
676 | down_read(&host->h_rwsem); |
677 | status = do_vfs_lock(fl); |
678 | up_read(&host->h_rwsem); |
679 | fl->fl_flags = fl_flags; |
680 | if (status == -ENOENT) { |
681 | status = 0; |
682 | goto out; |
683 | } |
684 | |
685 | atomic_inc(&req->a_count); |
686 | status = nlmclnt_async_call(nfs_file_cred(fl->fl_file), req, |
687 | NLMPROC_UNLOCK, &nlmclnt_unlock_ops); |
688 | if (status < 0) |
689 | goto out; |
690 | |
691 | if (resp->status == nlm_granted) |
692 | goto out; |
693 | |
694 | if (resp->status != nlm_lck_denied_nolocks) |
695 | printk("lockd: unexpected unlock status: %d\n", resp->status); |
696 | /* What to do now? I'm out of my depth... */ |
697 | status = -ENOLCK; |
698 | out: |
699 | nlm_release_call(req); |
700 | return status; |
701 | } |
702 | |
703 | static void nlmclnt_unlock_callback(struct rpc_task *task, void *data) |
704 | { |
705 | struct nlm_rqst *req = data; |
706 | u32 status = ntohl(req->a_res.status); |
707 | |
708 | if (RPC_ASSASSINATED(task)) |
709 | goto die; |
710 | |
711 | if (task->tk_status < 0) { |
712 | dprintk("lockd: unlock failed (err = %d)\n", -task->tk_status); |
713 | goto retry_rebind; |
714 | } |
715 | if (status == NLM_LCK_DENIED_GRACE_PERIOD) { |
716 | rpc_delay(task, NLMCLNT_GRACE_WAIT); |
717 | goto retry_unlock; |
718 | } |
719 | if (status != NLM_LCK_GRANTED) |
720 | printk(KERN_WARNING "lockd: unexpected unlock status: %d\n", status); |
721 | die: |
722 | return; |
723 | retry_rebind: |
724 | lock_kernel(); |
725 | nlm_rebind_host(req->a_host); |
726 | unlock_kernel(); |
727 | retry_unlock: |
728 | rpc_restart_call(task); |
729 | } |
730 | |
731 | static const struct rpc_call_ops nlmclnt_unlock_ops = { |
732 | .rpc_call_done = nlmclnt_unlock_callback, |
733 | .rpc_release = nlmclnt_rpc_release, |
734 | }; |
735 | |
736 | /* |
737 | * Cancel a blocked lock request. |
738 | * We always use an async RPC call for this in order not to hang a |
739 | * process that has been Ctrl-C'ed. |
740 | */ |
741 | static int nlmclnt_cancel(struct nlm_host *host, int block, struct file_lock *fl) |
742 | { |
743 | struct nlm_rqst *req; |
744 | int status; |
745 | |
746 | dprintk("lockd: blocking lock attempt was interrupted by a signal.\n" |
747 | " Attempting to cancel lock.\n"); |
748 | |
749 | req = nlm_alloc_call(nlm_get_host(host)); |
750 | if (!req) |
751 | return -ENOMEM; |
752 | req->a_flags = RPC_TASK_ASYNC; |
753 | |
754 | nlmclnt_setlockargs(req, fl); |
755 | req->a_args.block = block; |
756 | |
757 | atomic_inc(&req->a_count); |
758 | status = nlmclnt_async_call(nfs_file_cred(fl->fl_file), req, |
759 | NLMPROC_CANCEL, &nlmclnt_cancel_ops); |
760 | if (status == 0 && req->a_res.status == nlm_lck_denied) |
761 | status = -ENOLCK; |
762 | nlm_release_call(req); |
763 | return status; |
764 | } |
765 | |
766 | static void nlmclnt_cancel_callback(struct rpc_task *task, void *data) |
767 | { |
768 | struct nlm_rqst *req = data; |
769 | u32 status = ntohl(req->a_res.status); |
770 | |
771 | if (RPC_ASSASSINATED(task)) |
772 | goto die; |
773 | |
774 | if (task->tk_status < 0) { |
775 | dprintk("lockd: CANCEL call error %d, retrying.\n", |
776 | task->tk_status); |
777 | goto retry_cancel; |
778 | } |
779 | |
780 | dprintk("lockd: cancel status %u (task %u)\n", |
781 | status, task->tk_pid); |
782 | |
783 | switch (status) { |
784 | case NLM_LCK_GRANTED: |
785 | case NLM_LCK_DENIED_GRACE_PERIOD: |
786 | case NLM_LCK_DENIED: |
787 | /* Everything's good */ |
788 | break; |
789 | case NLM_LCK_DENIED_NOLOCKS: |
790 | dprintk("lockd: CANCEL failed (server has no locks)\n"); |
791 | goto retry_cancel; |
792 | default: |
793 | printk(KERN_NOTICE "lockd: weird return %d for CANCEL call\n", |
794 | status); |
795 | } |
796 | |
797 | die: |
798 | return; |
799 | |
800 | retry_cancel: |
801 | /* Don't ever retry more than 3 times */ |
802 | if (req->a_retries++ >= NLMCLNT_MAX_RETRIES) |
803 | goto die; |
804 | lock_kernel(); |
805 | nlm_rebind_host(req->a_host); |
806 | unlock_kernel(); |
807 | rpc_restart_call(task); |
808 | rpc_delay(task, 30 * HZ); |
809 | } |
810 | |
811 | static const struct rpc_call_ops nlmclnt_cancel_ops = { |
812 | .rpc_call_done = nlmclnt_cancel_callback, |
813 | .rpc_release = nlmclnt_rpc_release, |
814 | }; |
815 | |
816 | /* |
817 | * Convert an NLM status code to a generic kernel errno |
818 | */ |
819 | static int |
820 | nlm_stat_to_errno(__be32 status) |
821 | { |
822 | switch(ntohl(status)) { |
823 | case NLM_LCK_GRANTED: |
824 | return 0; |
825 | case NLM_LCK_DENIED: |
826 | return -EAGAIN; |
827 | case NLM_LCK_DENIED_NOLOCKS: |
828 | case NLM_LCK_DENIED_GRACE_PERIOD: |
829 | return -ENOLCK; |
830 | case NLM_LCK_BLOCKED: |
831 | printk(KERN_NOTICE "lockd: unexpected status NLM_BLOCKED\n"); |
832 | return -ENOLCK; |
833 | #ifdef CONFIG_LOCKD_V4 |
834 | case NLM_DEADLCK: |
835 | return -EDEADLK; |
836 | case NLM_ROFS: |
837 | return -EROFS; |
838 | case NLM_STALE_FH: |
839 | return -ESTALE; |
840 | case NLM_FBIG: |
841 | return -EOVERFLOW; |
842 | case NLM_FAILED: |
843 | return -ENOLCK; |
844 | #endif |
845 | } |
846 | printk(KERN_NOTICE "lockd: unexpected server status %d\n", status); |
847 | return -ENOLCK; |
848 | } |
849 |
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