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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/slab.h>
11#include <linux/types.h>
12#include <linux/errno.h>
13#include <linux/fs.h>
14#include <linux/nfs_fs.h>
15#include <linux/utsname.h>
16#include <linux/freezer.h>
17#include <linux/sunrpc/clnt.h>
18#include <linux/sunrpc/svc.h>
19#include <linux/lockd/lockd.h>
20
21#define NLMDBG_FACILITY NLMDBG_CLIENT
22#define NLMCLNT_GRACE_WAIT (5*HZ)
23#define NLMCLNT_POLL_TIMEOUT (30*HZ)
24#define NLMCLNT_MAX_RETRIES 3
25
26static int nlmclnt_test(struct nlm_rqst *, struct file_lock *);
27static int nlmclnt_lock(struct nlm_rqst *, struct file_lock *);
28static int nlmclnt_unlock(struct nlm_rqst *, struct file_lock *);
29static int nlm_stat_to_errno(__be32 stat);
30static void nlmclnt_locks_init_private(struct file_lock *fl, struct nlm_host *host);
31static int nlmclnt_cancel(struct nlm_host *, int , struct file_lock *);
32
33static const struct rpc_call_ops nlmclnt_unlock_ops;
34static const struct rpc_call_ops nlmclnt_cancel_ops;
35
36/*
37 * Cookie counter for NLM requests
38 */
39static atomic_t nlm_cookie = ATOMIC_INIT(0x1234);
40
41void nlmclnt_next_cookie(struct nlm_cookie *c)
42{
43 u32 cookie = atomic_inc_return(&nlm_cookie);
44
45 memcpy(c->data, &cookie, 4);
46 c->len=4;
47}
48
49static struct nlm_lockowner *nlm_get_lockowner(struct nlm_lockowner *lockowner)
50{
51 atomic_inc(&lockowner->count);
52 return lockowner;
53}
54
55static void nlm_put_lockowner(struct nlm_lockowner *lockowner)
56{
57 if (!atomic_dec_and_lock(&lockowner->count, &lockowner->host->h_lock))
58 return;
59 list_del(&lockowner->list);
60 spin_unlock(&lockowner->host->h_lock);
61 nlmclnt_release_host(lockowner->host);
62 kfree(lockowner);
63}
64
65static inline int nlm_pidbusy(struct nlm_host *host, uint32_t pid)
66{
67 struct nlm_lockowner *lockowner;
68 list_for_each_entry(lockowner, &host->h_lockowners, list) {
69 if (lockowner->pid == pid)
70 return -EBUSY;
71 }
72 return 0;
73}
74
75static inline uint32_t __nlm_alloc_pid(struct nlm_host *host)
76{
77 uint32_t res;
78 do {
79 res = host->h_pidcount++;
80 } while (nlm_pidbusy(host, res) < 0);
81 return res;
82}
83
84static struct nlm_lockowner *__nlm_find_lockowner(struct nlm_host *host, fl_owner_t owner)
85{
86 struct nlm_lockowner *lockowner;
87 list_for_each_entry(lockowner, &host->h_lockowners, list) {
88 if (lockowner->owner != owner)
89 continue;
90 return nlm_get_lockowner(lockowner);
91 }
92 return NULL;
93}
94
95static struct nlm_lockowner *nlm_find_lockowner(struct nlm_host *host, fl_owner_t owner)
96{
97 struct nlm_lockowner *res, *new = NULL;
98
99 spin_lock(&host->h_lock);
100 res = __nlm_find_lockowner(host, owner);
101 if (res == NULL) {
102 spin_unlock(&host->h_lock);
103 new = kmalloc(sizeof(*new), GFP_KERNEL);
104 spin_lock(&host->h_lock);
105 res = __nlm_find_lockowner(host, owner);
106 if (res == NULL && new != NULL) {
107 res = new;
108 atomic_set(&new->count, 1);
109 new->owner = owner;
110 new->pid = __nlm_alloc_pid(host);
111 new->host = nlm_get_host(host);
112 list_add(&new->list, &host->h_lockowners);
113 new = NULL;
114 }
115 }
116 spin_unlock(&host->h_lock);
117 kfree(new);
118 return res;
119}
120
121/*
122 * Initialize arguments for TEST/LOCK/UNLOCK/CANCEL calls
123 */
124static void nlmclnt_setlockargs(struct nlm_rqst *req, struct file_lock *fl)
125{
126 struct nlm_args *argp = &req->a_args;
127 struct nlm_lock *lock = &argp->lock;
128 char *nodename = req->a_host->h_rpcclnt->cl_nodename;
129
130 nlmclnt_next_cookie(&argp->cookie);
131 memcpy(&lock->fh, NFS_FH(file_inode(fl->fl_file)), sizeof(struct nfs_fh));
132 lock->caller = 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 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
143static void nlmclnt_release_lockargs(struct nlm_rqst *req)
144{
145 WARN_ON_ONCE(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 */
155int nlmclnt_proc(struct nlm_host *host, int cmd, struct file_lock *fl)
156{
157 struct nlm_rqst *call;
158 int status;
159
160 call = nlm_alloc_call(host);
161 if (call == NULL)
162 return -ENOMEM;
163
164 nlmclnt_locks_init_private(fl, host);
165 if (!fl->fl_u.nfs_fl.owner) {
166 /* lockowner allocation has failed */
167 nlmclnt_release_call(call);
168 return -ENOMEM;
169 }
170 /* Set up the argument struct */
171 nlmclnt_setlockargs(call, fl);
172
173 if (IS_SETLK(cmd) || IS_SETLKW(cmd)) {
174 if (fl->fl_type != F_UNLCK) {
175 call->a_args.block = IS_SETLKW(cmd) ? 1 : 0;
176 status = nlmclnt_lock(call, fl);
177 } else
178 status = nlmclnt_unlock(call, fl);
179 } else if (IS_GETLK(cmd))
180 status = nlmclnt_test(call, fl);
181 else
182 status = -EINVAL;
183 fl->fl_ops->fl_release_private(fl);
184 fl->fl_ops = NULL;
185
186 dprintk("lockd: clnt proc returns %d\n", status);
187 return status;
188}
189EXPORT_SYMBOL_GPL(nlmclnt_proc);
190
191/*
192 * Allocate an NLM RPC call struct
193 */
194struct nlm_rqst *nlm_alloc_call(struct nlm_host *host)
195{
196 struct nlm_rqst *call;
197
198 for(;;) {
199 call = kzalloc(sizeof(*call), GFP_KERNEL);
200 if (call != NULL) {
201 atomic_set(&call->a_count, 1);
202 locks_init_lock(&call->a_args.lock.fl);
203 locks_init_lock(&call->a_res.lock.fl);
204 call->a_host = nlm_get_host(host);
205 return call;
206 }
207 if (signalled())
208 break;
209 printk("nlm_alloc_call: failed, waiting for memory\n");
210 schedule_timeout_interruptible(5*HZ);
211 }
212 return NULL;
213}
214
215void nlmclnt_release_call(struct nlm_rqst *call)
216{
217 if (!atomic_dec_and_test(&call->a_count))
218 return;
219 nlmclnt_release_host(call->a_host);
220 nlmclnt_release_lockargs(call);
221 kfree(call);
222}
223
224static void nlmclnt_rpc_release(void *data)
225{
226 nlmclnt_release_call(data);
227}
228
229static int nlm_wait_on_grace(wait_queue_head_t *queue)
230{
231 DEFINE_WAIT(wait);
232 int status = -EINTR;
233
234 prepare_to_wait(queue, &wait, TASK_INTERRUPTIBLE);
235 if (!signalled ()) {
236 schedule_timeout(NLMCLNT_GRACE_WAIT);
237 try_to_freeze();
238 if (!signalled ())
239 status = 0;
240 }
241 finish_wait(queue, &wait);
242 return status;
243}
244
245/*
246 * Generic NLM call
247 */
248static int
249nlmclnt_call(struct rpc_cred *cred, struct nlm_rqst *req, u32 proc)
250{
251 struct nlm_host *host = req->a_host;
252 struct rpc_clnt *clnt;
253 struct nlm_args *argp = &req->a_args;
254 struct nlm_res *resp = &req->a_res;
255 struct rpc_message msg = {
256 .rpc_argp = argp,
257 .rpc_resp = resp,
258 .rpc_cred = cred,
259 };
260 int status;
261
262 dprintk("lockd: call procedure %d on %s\n",
263 (int)proc, host->h_name);
264
265 do {
266 if (host->h_reclaiming && !argp->reclaim)
267 goto in_grace_period;
268
269 /* If we have no RPC client yet, create one. */
270 if ((clnt = nlm_bind_host(host)) == NULL)
271 return -ENOLCK;
272 msg.rpc_proc = &clnt->cl_procinfo[proc];
273
274 /* Perform the RPC call. If an error occurs, try again */
275 if ((status = rpc_call_sync(clnt, &msg, 0)) < 0) {
276 dprintk("lockd: rpc_call returned error %d\n", -status);
277 switch (status) {
278 case -EPROTONOSUPPORT:
279 status = -EINVAL;
280 break;
281 case -ECONNREFUSED:
282 case -ETIMEDOUT:
283 case -ENOTCONN:
284 nlm_rebind_host(host);
285 status = -EAGAIN;
286 break;
287 case -ERESTARTSYS:
288 return signalled () ? -EINTR : status;
289 default:
290 break;
291 }
292 break;
293 } else
294 if (resp->status == nlm_lck_denied_grace_period) {
295 dprintk("lockd: server in grace period\n");
296 if (argp->reclaim) {
297 printk(KERN_WARNING
298 "lockd: spurious grace period reject?!\n");
299 return -ENOLCK;
300 }
301 } else {
302 if (!argp->reclaim) {
303 /* We appear to be out of the grace period */
304 wake_up_all(&host->h_gracewait);
305 }
306 dprintk("lockd: server returns status %d\n",
307 ntohl(resp->status));
308 return 0; /* Okay, call complete */
309 }
310
311in_grace_period:
312 /*
313 * The server has rebooted and appears to be in the grace
314 * period during which locks are only allowed to be
315 * reclaimed.
316 * We can only back off and try again later.
317 */
318 status = nlm_wait_on_grace(&host->h_gracewait);
319 } while (status == 0);
320
321 return status;
322}
323
324/*
325 * Generic NLM call, async version.
326 */
327static struct rpc_task *__nlm_async_call(struct nlm_rqst *req, u32 proc, struct rpc_message *msg, const struct rpc_call_ops *tk_ops)
328{
329 struct nlm_host *host = req->a_host;
330 struct rpc_clnt *clnt;
331 struct rpc_task_setup task_setup_data = {
332 .rpc_message = msg,
333 .callback_ops = tk_ops,
334 .callback_data = req,
335 .flags = RPC_TASK_ASYNC,
336 };
337
338 dprintk("lockd: call procedure %d on %s (async)\n",
339 (int)proc, host->h_name);
340
341 /* If we have no RPC client yet, create one. */
342 clnt = nlm_bind_host(host);
343 if (clnt == NULL)
344 goto out_err;
345 msg->rpc_proc = &clnt->cl_procinfo[proc];
346 task_setup_data.rpc_client = clnt;
347
348 /* bootstrap and kick off the async RPC call */
349 return rpc_run_task(&task_setup_data);
350out_err:
351 tk_ops->rpc_release(req);
352 return ERR_PTR(-ENOLCK);
353}
354
355static int nlm_do_async_call(struct nlm_rqst *req, u32 proc, struct rpc_message *msg, const struct rpc_call_ops *tk_ops)
356{
357 struct rpc_task *task;
358
359 task = __nlm_async_call(req, proc, msg, tk_ops);
360 if (IS_ERR(task))
361 return PTR_ERR(task);
362 rpc_put_task(task);
363 return 0;
364}
365
366/*
367 * NLM asynchronous call.
368 */
369int nlm_async_call(struct nlm_rqst *req, u32 proc, const struct rpc_call_ops *tk_ops)
370{
371 struct rpc_message msg = {
372 .rpc_argp = &req->a_args,
373 .rpc_resp = &req->a_res,
374 };
375 return nlm_do_async_call(req, proc, &msg, tk_ops);
376}
377
378int nlm_async_reply(struct nlm_rqst *req, u32 proc, const struct rpc_call_ops *tk_ops)
379{
380 struct rpc_message msg = {
381 .rpc_argp = &req->a_res,
382 };
383 return nlm_do_async_call(req, proc, &msg, tk_ops);
384}
385
386/*
387 * NLM client asynchronous call.
388 *
389 * Note that although the calls are asynchronous, and are therefore
390 * guaranteed to complete, we still always attempt to wait for
391 * completion in order to be able to correctly track the lock
392 * state.
393 */
394static int nlmclnt_async_call(struct rpc_cred *cred, struct nlm_rqst *req, u32 proc, const struct rpc_call_ops *tk_ops)
395{
396 struct rpc_message msg = {
397 .rpc_argp = &req->a_args,
398 .rpc_resp = &req->a_res,
399 .rpc_cred = cred,
400 };
401 struct rpc_task *task;
402 int err;
403
404 task = __nlm_async_call(req, proc, &msg, tk_ops);
405 if (IS_ERR(task))
406 return PTR_ERR(task);
407 err = rpc_wait_for_completion_task(task);
408 rpc_put_task(task);
409 return err;
410}
411
412/*
413 * TEST for the presence of a conflicting lock
414 */
415static int
416nlmclnt_test(struct nlm_rqst *req, struct file_lock *fl)
417{
418 int status;
419
420 status = nlmclnt_call(nfs_file_cred(fl->fl_file), req, NLMPROC_TEST);
421 if (status < 0)
422 goto out;
423
424 switch (req->a_res.status) {
425 case nlm_granted:
426 fl->fl_type = F_UNLCK;
427 break;
428 case nlm_lck_denied:
429 /*
430 * Report the conflicting lock back to the application.
431 */
432 fl->fl_start = req->a_res.lock.fl.fl_start;
433 fl->fl_end = req->a_res.lock.fl.fl_end;
434 fl->fl_type = req->a_res.lock.fl.fl_type;
435 fl->fl_pid = 0;
436 break;
437 default:
438 status = nlm_stat_to_errno(req->a_res.status);
439 }
440out:
441 nlmclnt_release_call(req);
442 return status;
443}
444
445static void nlmclnt_locks_copy_lock(struct file_lock *new, struct file_lock *fl)
446{
447 spin_lock(&fl->fl_u.nfs_fl.owner->host->h_lock);
448 new->fl_u.nfs_fl.state = fl->fl_u.nfs_fl.state;
449 new->fl_u.nfs_fl.owner = nlm_get_lockowner(fl->fl_u.nfs_fl.owner);
450 list_add_tail(&new->fl_u.nfs_fl.list, &fl->fl_u.nfs_fl.owner->host->h_granted);
451 spin_unlock(&fl->fl_u.nfs_fl.owner->host->h_lock);
452}
453
454static void nlmclnt_locks_release_private(struct file_lock *fl)
455{
456 spin_lock(&fl->fl_u.nfs_fl.owner->host->h_lock);
457 list_del(&fl->fl_u.nfs_fl.list);
458 spin_unlock(&fl->fl_u.nfs_fl.owner->host->h_lock);
459 nlm_put_lockowner(fl->fl_u.nfs_fl.owner);
460}
461
462static 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
467static void nlmclnt_locks_init_private(struct file_lock *fl, struct nlm_host *host)
468{
469 fl->fl_u.nfs_fl.state = 0;
470 fl->fl_u.nfs_fl.owner = nlm_find_lockowner(host, fl->fl_owner);
471 INIT_LIST_HEAD(&fl->fl_u.nfs_fl.list);
472 fl->fl_ops = &nlmclnt_lock_ops;
473}
474
475static int do_vfs_lock(struct file_lock *fl)
476{
477 return locks_lock_file_wait(fl->fl_file, fl);
478}
479
480/*
481 * LOCK: Try to create a lock
482 *
483 * Programmer Harassment Alert
484 *
485 * When given a blocking lock request in a sync RPC call, the HPUX lockd
486 * will faithfully return LCK_BLOCKED but never cares to notify us when
487 * the lock could be granted. This way, our local process could hang
488 * around forever waiting for the callback.
489 *
490 * Solution A: Implement busy-waiting
491 * Solution B: Use the async version of the call (NLM_LOCK_{MSG,RES})
492 *
493 * For now I am implementing solution A, because I hate the idea of
494 * re-implementing lockd for a third time in two months. The async
495 * calls shouldn't be too hard to do, however.
496 *
497 * This is one of the lovely things about standards in the NFS area:
498 * they're so soft and squishy you can't really blame HP for doing this.
499 */
500static int
501nlmclnt_lock(struct nlm_rqst *req, struct file_lock *fl)
502{
503 struct rpc_cred *cred = nfs_file_cred(fl->fl_file);
504 struct nlm_host *host = req->a_host;
505 struct nlm_res *resp = &req->a_res;
506 struct nlm_wait *block = NULL;
507 unsigned char fl_flags = fl->fl_flags;
508 unsigned char fl_type;
509 int status = -ENOLCK;
510
511 if (nsm_monitor(host) < 0)
512 goto out;
513 req->a_args.state = nsm_local_state;
514
515 fl->fl_flags |= FL_ACCESS;
516 status = do_vfs_lock(fl);
517 fl->fl_flags = fl_flags;
518 if (status < 0)
519 goto out;
520
521 block = nlmclnt_prepare_block(host, fl);
522again:
523 /*
524 * Initialise resp->status to a valid non-zero value,
525 * since 0 == nlm_lck_granted
526 */
527 resp->status = nlm_lck_blocked;
528 for(;;) {
529 /* Reboot protection */
530 fl->fl_u.nfs_fl.state = host->h_state;
531 status = nlmclnt_call(cred, req, NLMPROC_LOCK);
532 if (status < 0)
533 break;
534 /* Did a reclaimer thread notify us of a server reboot? */
535 if (resp->status == nlm_lck_denied_grace_period)
536 continue;
537 if (resp->status != nlm_lck_blocked)
538 break;
539 /* Wait on an NLM blocking lock */
540 status = nlmclnt_block(block, req, NLMCLNT_POLL_TIMEOUT);
541 if (status < 0)
542 break;
543 if (resp->status != nlm_lck_blocked)
544 break;
545 }
546
547 /* if we were interrupted while blocking, then cancel the lock request
548 * and exit
549 */
550 if (resp->status == nlm_lck_blocked) {
551 if (!req->a_args.block)
552 goto out_unlock;
553 if (nlmclnt_cancel(host, req->a_args.block, fl) == 0)
554 goto out_unblock;
555 }
556
557 if (resp->status == nlm_granted) {
558 down_read(&host->h_rwsem);
559 /* Check whether or not the server has rebooted */
560 if (fl->fl_u.nfs_fl.state != host->h_state) {
561 up_read(&host->h_rwsem);
562 goto again;
563 }
564 /* Ensure the resulting lock will get added to granted list */
565 fl->fl_flags |= FL_SLEEP;
566 if (do_vfs_lock(fl) < 0)
567 printk(KERN_WARNING "%s: VFS is out of sync with lock manager!\n", __func__);
568 up_read(&host->h_rwsem);
569 fl->fl_flags = fl_flags;
570 status = 0;
571 }
572 if (status < 0)
573 goto out_unlock;
574 /*
575 * EAGAIN doesn't make sense for sleeping locks, and in some
576 * cases NLM_LCK_DENIED is returned for a permanent error. So
577 * turn it into an ENOLCK.
578 */
579 if (resp->status == nlm_lck_denied && (fl_flags & FL_SLEEP))
580 status = -ENOLCK;
581 else
582 status = nlm_stat_to_errno(resp->status);
583out_unblock:
584 nlmclnt_finish_block(block);
585out:
586 nlmclnt_release_call(req);
587 return status;
588out_unlock:
589 /* Fatal error: ensure that we remove the lock altogether */
590 dprintk("lockd: lock attempt ended in fatal error.\n"
591 " Attempting to unlock.\n");
592 nlmclnt_finish_block(block);
593 fl_type = fl->fl_type;
594 fl->fl_type = F_UNLCK;
595 down_read(&host->h_rwsem);
596 do_vfs_lock(fl);
597 up_read(&host->h_rwsem);
598 fl->fl_type = fl_type;
599 fl->fl_flags = fl_flags;
600 nlmclnt_async_call(cred, req, NLMPROC_UNLOCK, &nlmclnt_unlock_ops);
601 return status;
602}
603
604/*
605 * RECLAIM: Try to reclaim a lock
606 */
607int
608nlmclnt_reclaim(struct nlm_host *host, struct file_lock *fl,
609 struct nlm_rqst *req)
610{
611 int status;
612
613 memset(req, 0, sizeof(*req));
614 locks_init_lock(&req->a_args.lock.fl);
615 locks_init_lock(&req->a_res.lock.fl);
616 req->a_host = host;
617
618 /* Set up the argument struct */
619 nlmclnt_setlockargs(req, fl);
620 req->a_args.reclaim = 1;
621
622 status = nlmclnt_call(nfs_file_cred(fl->fl_file), req, NLMPROC_LOCK);
623 if (status >= 0 && req->a_res.status == nlm_granted)
624 return 0;
625
626 printk(KERN_WARNING "lockd: failed to reclaim lock for pid %d "
627 "(errno %d, status %d)\n", fl->fl_pid,
628 status, ntohl(req->a_res.status));
629
630 /*
631 * FIXME: This is a serious failure. We can
632 *
633 * a. Ignore the problem
634 * b. Send the owning process some signal (Linux doesn't have
635 * SIGLOST, though...)
636 * c. Retry the operation
637 *
638 * Until someone comes up with a simple implementation
639 * for b or c, I'll choose option a.
640 */
641
642 return -ENOLCK;
643}
644
645/*
646 * UNLOCK: remove an existing lock
647 */
648static int
649nlmclnt_unlock(struct nlm_rqst *req, struct file_lock *fl)
650{
651 struct nlm_host *host = req->a_host;
652 struct nlm_res *resp = &req->a_res;
653 int status;
654 unsigned char fl_flags = fl->fl_flags;
655
656 /*
657 * Note: the server is supposed to either grant us the unlock
658 * request, or to deny it with NLM_LCK_DENIED_GRACE_PERIOD. In either
659 * case, we want to unlock.
660 */
661 fl->fl_flags |= FL_EXISTS;
662 down_read(&host->h_rwsem);
663 status = do_vfs_lock(fl);
664 up_read(&host->h_rwsem);
665 fl->fl_flags = fl_flags;
666 if (status == -ENOENT) {
667 status = 0;
668 goto out;
669 }
670
671 atomic_inc(&req->a_count);
672 status = nlmclnt_async_call(nfs_file_cred(fl->fl_file), req,
673 NLMPROC_UNLOCK, &nlmclnt_unlock_ops);
674 if (status < 0)
675 goto out;
676
677 if (resp->status == nlm_granted)
678 goto out;
679
680 if (resp->status != nlm_lck_denied_nolocks)
681 printk("lockd: unexpected unlock status: %d\n",
682 ntohl(resp->status));
683 /* What to do now? I'm out of my depth... */
684 status = -ENOLCK;
685out:
686 nlmclnt_release_call(req);
687 return status;
688}
689
690static void nlmclnt_unlock_callback(struct rpc_task *task, void *data)
691{
692 struct nlm_rqst *req = data;
693 u32 status = ntohl(req->a_res.status);
694
695 if (RPC_ASSASSINATED(task))
696 goto die;
697
698 if (task->tk_status < 0) {
699 dprintk("lockd: unlock failed (err = %d)\n", -task->tk_status);
700 switch (task->tk_status) {
701 case -EACCES:
702 case -EIO:
703 goto die;
704 default:
705 goto retry_rebind;
706 }
707 }
708 if (status == NLM_LCK_DENIED_GRACE_PERIOD) {
709 rpc_delay(task, NLMCLNT_GRACE_WAIT);
710 goto retry_unlock;
711 }
712 if (status != NLM_LCK_GRANTED)
713 printk(KERN_WARNING "lockd: unexpected unlock status: %d\n", status);
714die:
715 return;
716 retry_rebind:
717 nlm_rebind_host(req->a_host);
718 retry_unlock:
719 rpc_restart_call(task);
720}
721
722static const struct rpc_call_ops nlmclnt_unlock_ops = {
723 .rpc_call_done = nlmclnt_unlock_callback,
724 .rpc_release = nlmclnt_rpc_release,
725};
726
727/*
728 * Cancel a blocked lock request.
729 * We always use an async RPC call for this in order not to hang a
730 * process that has been Ctrl-C'ed.
731 */
732static int nlmclnt_cancel(struct nlm_host *host, int block, struct file_lock *fl)
733{
734 struct nlm_rqst *req;
735 int status;
736
737 dprintk("lockd: blocking lock attempt was interrupted by a signal.\n"
738 " Attempting to cancel lock.\n");
739
740 req = nlm_alloc_call(host);
741 if (!req)
742 return -ENOMEM;
743 req->a_flags = RPC_TASK_ASYNC;
744
745 nlmclnt_setlockargs(req, fl);
746 req->a_args.block = block;
747
748 atomic_inc(&req->a_count);
749 status = nlmclnt_async_call(nfs_file_cred(fl->fl_file), req,
750 NLMPROC_CANCEL, &nlmclnt_cancel_ops);
751 if (status == 0 && req->a_res.status == nlm_lck_denied)
752 status = -ENOLCK;
753 nlmclnt_release_call(req);
754 return status;
755}
756
757static void nlmclnt_cancel_callback(struct rpc_task *task, void *data)
758{
759 struct nlm_rqst *req = data;
760 u32 status = ntohl(req->a_res.status);
761
762 if (RPC_ASSASSINATED(task))
763 goto die;
764
765 if (task->tk_status < 0) {
766 dprintk("lockd: CANCEL call error %d, retrying.\n",
767 task->tk_status);
768 goto retry_cancel;
769 }
770
771 dprintk("lockd: cancel status %u (task %u)\n",
772 status, task->tk_pid);
773
774 switch (status) {
775 case NLM_LCK_GRANTED:
776 case NLM_LCK_DENIED_GRACE_PERIOD:
777 case NLM_LCK_DENIED:
778 /* Everything's good */
779 break;
780 case NLM_LCK_DENIED_NOLOCKS:
781 dprintk("lockd: CANCEL failed (server has no locks)\n");
782 goto retry_cancel;
783 default:
784 printk(KERN_NOTICE "lockd: weird return %d for CANCEL call\n",
785 status);
786 }
787
788die:
789 return;
790
791retry_cancel:
792 /* Don't ever retry more than 3 times */
793 if (req->a_retries++ >= NLMCLNT_MAX_RETRIES)
794 goto die;
795 nlm_rebind_host(req->a_host);
796 rpc_restart_call(task);
797 rpc_delay(task, 30 * HZ);
798}
799
800static const struct rpc_call_ops nlmclnt_cancel_ops = {
801 .rpc_call_done = nlmclnt_cancel_callback,
802 .rpc_release = nlmclnt_rpc_release,
803};
804
805/*
806 * Convert an NLM status code to a generic kernel errno
807 */
808static int
809nlm_stat_to_errno(__be32 status)
810{
811 switch(ntohl(status)) {
812 case NLM_LCK_GRANTED:
813 return 0;
814 case NLM_LCK_DENIED:
815 return -EAGAIN;
816 case NLM_LCK_DENIED_NOLOCKS:
817 case NLM_LCK_DENIED_GRACE_PERIOD:
818 return -ENOLCK;
819 case NLM_LCK_BLOCKED:
820 printk(KERN_NOTICE "lockd: unexpected status NLM_BLOCKED\n");
821 return -ENOLCK;
822#ifdef CONFIG_LOCKD_V4
823 case NLM_DEADLCK:
824 return -EDEADLK;
825 case NLM_ROFS:
826 return -EROFS;
827 case NLM_STALE_FH:
828 return -ESTALE;
829 case NLM_FBIG:
830 return -EOVERFLOW;
831 case NLM_FAILED:
832 return -ENOLCK;
833#endif
834 }
835 printk(KERN_NOTICE "lockd: unexpected server status %d\n",
836 ntohl(status));
837 return -ENOLCK;
838}
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * linux/fs/lockd/clntproc.c
4 *
5 * RPC procedures for the client side NLM implementation
6 *
7 * Copyright (C) 1996, Olaf Kirch <okir@monad.swb.de>
8 */
9
10#include <linux/module.h>
11#include <linux/slab.h>
12#include <linux/types.h>
13#include <linux/errno.h>
14#include <linux/fs.h>
15#include <linux/filelock.h>
16#include <linux/nfs_fs.h>
17#include <linux/utsname.h>
18#include <linux/freezer.h>
19#include <linux/sunrpc/clnt.h>
20#include <linux/sunrpc/svc.h>
21#include <linux/lockd/lockd.h>
22
23#include "trace.h"
24
25#define NLMDBG_FACILITY NLMDBG_CLIENT
26#define NLMCLNT_GRACE_WAIT (5*HZ)
27#define NLMCLNT_POLL_TIMEOUT (30*HZ)
28#define NLMCLNT_MAX_RETRIES 3
29
30static int nlmclnt_test(struct nlm_rqst *, struct file_lock *);
31static int nlmclnt_lock(struct nlm_rqst *, struct file_lock *);
32static int nlmclnt_unlock(struct nlm_rqst *, struct file_lock *);
33static int nlm_stat_to_errno(__be32 stat);
34static void nlmclnt_locks_init_private(struct file_lock *fl, struct nlm_host *host);
35static int nlmclnt_cancel(struct nlm_host *, int , struct file_lock *);
36
37static const struct rpc_call_ops nlmclnt_unlock_ops;
38static const struct rpc_call_ops nlmclnt_cancel_ops;
39
40/*
41 * Cookie counter for NLM requests
42 */
43static atomic_t nlm_cookie = ATOMIC_INIT(0x1234);
44
45void nlmclnt_next_cookie(struct nlm_cookie *c)
46{
47 u32 cookie = atomic_inc_return(&nlm_cookie);
48
49 memcpy(c->data, &cookie, 4);
50 c->len=4;
51}
52
53static struct nlm_lockowner *
54nlmclnt_get_lockowner(struct nlm_lockowner *lockowner)
55{
56 refcount_inc(&lockowner->count);
57 return lockowner;
58}
59
60static void nlmclnt_put_lockowner(struct nlm_lockowner *lockowner)
61{
62 if (!refcount_dec_and_lock(&lockowner->count, &lockowner->host->h_lock))
63 return;
64 list_del(&lockowner->list);
65 spin_unlock(&lockowner->host->h_lock);
66 nlmclnt_release_host(lockowner->host);
67 kfree(lockowner);
68}
69
70static inline int nlm_pidbusy(struct nlm_host *host, uint32_t pid)
71{
72 struct nlm_lockowner *lockowner;
73 list_for_each_entry(lockowner, &host->h_lockowners, list) {
74 if (lockowner->pid == pid)
75 return -EBUSY;
76 }
77 return 0;
78}
79
80static inline uint32_t __nlm_alloc_pid(struct nlm_host *host)
81{
82 uint32_t res;
83 do {
84 res = host->h_pidcount++;
85 } while (nlm_pidbusy(host, res) < 0);
86 return res;
87}
88
89static struct nlm_lockowner *__nlmclnt_find_lockowner(struct nlm_host *host, fl_owner_t owner)
90{
91 struct nlm_lockowner *lockowner;
92 list_for_each_entry(lockowner, &host->h_lockowners, list) {
93 if (lockowner->owner != owner)
94 continue;
95 return nlmclnt_get_lockowner(lockowner);
96 }
97 return NULL;
98}
99
100static struct nlm_lockowner *nlmclnt_find_lockowner(struct nlm_host *host, fl_owner_t owner)
101{
102 struct nlm_lockowner *res, *new = NULL;
103
104 spin_lock(&host->h_lock);
105 res = __nlmclnt_find_lockowner(host, owner);
106 if (res == NULL) {
107 spin_unlock(&host->h_lock);
108 new = kmalloc(sizeof(*new), GFP_KERNEL);
109 spin_lock(&host->h_lock);
110 res = __nlmclnt_find_lockowner(host, owner);
111 if (res == NULL && new != NULL) {
112 res = new;
113 refcount_set(&new->count, 1);
114 new->owner = owner;
115 new->pid = __nlm_alloc_pid(host);
116 new->host = nlm_get_host(host);
117 list_add(&new->list, &host->h_lockowners);
118 new = NULL;
119 }
120 }
121 spin_unlock(&host->h_lock);
122 kfree(new);
123 return res;
124}
125
126/*
127 * Initialize arguments for TEST/LOCK/UNLOCK/CANCEL calls
128 */
129static void nlmclnt_setlockargs(struct nlm_rqst *req, struct file_lock *fl)
130{
131 struct nlm_args *argp = &req->a_args;
132 struct nlm_lock *lock = &argp->lock;
133 char *nodename = req->a_host->h_rpcclnt->cl_nodename;
134
135 nlmclnt_next_cookie(&argp->cookie);
136 memcpy(&lock->fh, NFS_FH(file_inode(fl->fl_file)), sizeof(struct nfs_fh));
137 lock->caller = nodename;
138 lock->oh.data = req->a_owner;
139 lock->oh.len = snprintf(req->a_owner, sizeof(req->a_owner), "%u@%s",
140 (unsigned int)fl->fl_u.nfs_fl.owner->pid,
141 nodename);
142 lock->svid = fl->fl_u.nfs_fl.owner->pid;
143 lock->fl.fl_start = fl->fl_start;
144 lock->fl.fl_end = fl->fl_end;
145 lock->fl.fl_type = fl->fl_type;
146}
147
148static void nlmclnt_release_lockargs(struct nlm_rqst *req)
149{
150 WARN_ON_ONCE(req->a_args.lock.fl.fl_ops != NULL);
151}
152
153/**
154 * nlmclnt_proc - Perform a single client-side lock request
155 * @host: address of a valid nlm_host context representing the NLM server
156 * @cmd: fcntl-style file lock operation to perform
157 * @fl: address of arguments for the lock operation
158 * @data: address of data to be sent to callback operations
159 *
160 */
161int nlmclnt_proc(struct nlm_host *host, int cmd, struct file_lock *fl, void *data)
162{
163 struct nlm_rqst *call;
164 int status;
165 const struct nlmclnt_operations *nlmclnt_ops = host->h_nlmclnt_ops;
166
167 call = nlm_alloc_call(host);
168 if (call == NULL)
169 return -ENOMEM;
170
171 if (nlmclnt_ops && nlmclnt_ops->nlmclnt_alloc_call)
172 nlmclnt_ops->nlmclnt_alloc_call(data);
173
174 nlmclnt_locks_init_private(fl, host);
175 if (!fl->fl_u.nfs_fl.owner) {
176 /* lockowner allocation has failed */
177 nlmclnt_release_call(call);
178 return -ENOMEM;
179 }
180 /* Set up the argument struct */
181 nlmclnt_setlockargs(call, fl);
182 call->a_callback_data = data;
183
184 if (IS_SETLK(cmd) || IS_SETLKW(cmd)) {
185 if (fl->fl_type != F_UNLCK) {
186 call->a_args.block = IS_SETLKW(cmd) ? 1 : 0;
187 status = nlmclnt_lock(call, fl);
188 } else
189 status = nlmclnt_unlock(call, fl);
190 } else if (IS_GETLK(cmd))
191 status = nlmclnt_test(call, fl);
192 else
193 status = -EINVAL;
194 fl->fl_ops->fl_release_private(fl);
195 fl->fl_ops = NULL;
196
197 dprintk("lockd: clnt proc returns %d\n", status);
198 return status;
199}
200EXPORT_SYMBOL_GPL(nlmclnt_proc);
201
202/*
203 * Allocate an NLM RPC call struct
204 */
205struct nlm_rqst *nlm_alloc_call(struct nlm_host *host)
206{
207 struct nlm_rqst *call;
208
209 for(;;) {
210 call = kzalloc(sizeof(*call), GFP_KERNEL);
211 if (call != NULL) {
212 refcount_set(&call->a_count, 1);
213 locks_init_lock(&call->a_args.lock.fl);
214 locks_init_lock(&call->a_res.lock.fl);
215 call->a_host = nlm_get_host(host);
216 return call;
217 }
218 if (signalled())
219 break;
220 printk("nlm_alloc_call: failed, waiting for memory\n");
221 schedule_timeout_interruptible(5*HZ);
222 }
223 return NULL;
224}
225
226void nlmclnt_release_call(struct nlm_rqst *call)
227{
228 const struct nlmclnt_operations *nlmclnt_ops = call->a_host->h_nlmclnt_ops;
229
230 if (!refcount_dec_and_test(&call->a_count))
231 return;
232 if (nlmclnt_ops && nlmclnt_ops->nlmclnt_release_call)
233 nlmclnt_ops->nlmclnt_release_call(call->a_callback_data);
234 nlmclnt_release_host(call->a_host);
235 nlmclnt_release_lockargs(call);
236 kfree(call);
237}
238
239static void nlmclnt_rpc_release(void *data)
240{
241 nlmclnt_release_call(data);
242}
243
244static int nlm_wait_on_grace(wait_queue_head_t *queue)
245{
246 DEFINE_WAIT(wait);
247 int status = -EINTR;
248
249 prepare_to_wait(queue, &wait, TASK_INTERRUPTIBLE);
250 if (!signalled ()) {
251 schedule_timeout(NLMCLNT_GRACE_WAIT);
252 try_to_freeze();
253 if (!signalled ())
254 status = 0;
255 }
256 finish_wait(queue, &wait);
257 return status;
258}
259
260/*
261 * Generic NLM call
262 */
263static int
264nlmclnt_call(const struct cred *cred, struct nlm_rqst *req, u32 proc)
265{
266 struct nlm_host *host = req->a_host;
267 struct rpc_clnt *clnt;
268 struct nlm_args *argp = &req->a_args;
269 struct nlm_res *resp = &req->a_res;
270 struct rpc_message msg = {
271 .rpc_argp = argp,
272 .rpc_resp = resp,
273 .rpc_cred = cred,
274 };
275 int status;
276
277 dprintk("lockd: call procedure %d on %s\n",
278 (int)proc, host->h_name);
279
280 do {
281 if (host->h_reclaiming && !argp->reclaim)
282 goto in_grace_period;
283
284 /* If we have no RPC client yet, create one. */
285 if ((clnt = nlm_bind_host(host)) == NULL)
286 return -ENOLCK;
287 msg.rpc_proc = &clnt->cl_procinfo[proc];
288
289 /* Perform the RPC call. If an error occurs, try again */
290 if ((status = rpc_call_sync(clnt, &msg, 0)) < 0) {
291 dprintk("lockd: rpc_call returned error %d\n", -status);
292 switch (status) {
293 case -EPROTONOSUPPORT:
294 status = -EINVAL;
295 break;
296 case -ECONNREFUSED:
297 case -ETIMEDOUT:
298 case -ENOTCONN:
299 nlm_rebind_host(host);
300 status = -EAGAIN;
301 break;
302 case -ERESTARTSYS:
303 return signalled () ? -EINTR : status;
304 default:
305 break;
306 }
307 break;
308 } else
309 if (resp->status == nlm_lck_denied_grace_period) {
310 dprintk("lockd: server in grace period\n");
311 if (argp->reclaim) {
312 printk(KERN_WARNING
313 "lockd: spurious grace period reject?!\n");
314 return -ENOLCK;
315 }
316 } else {
317 if (!argp->reclaim) {
318 /* We appear to be out of the grace period */
319 wake_up_all(&host->h_gracewait);
320 }
321 dprintk("lockd: server returns status %d\n",
322 ntohl(resp->status));
323 return 0; /* Okay, call complete */
324 }
325
326in_grace_period:
327 /*
328 * The server has rebooted and appears to be in the grace
329 * period during which locks are only allowed to be
330 * reclaimed.
331 * We can only back off and try again later.
332 */
333 status = nlm_wait_on_grace(&host->h_gracewait);
334 } while (status == 0);
335
336 return status;
337}
338
339/*
340 * Generic NLM call, async version.
341 */
342static struct rpc_task *__nlm_async_call(struct nlm_rqst *req, u32 proc, struct rpc_message *msg, const struct rpc_call_ops *tk_ops)
343{
344 struct nlm_host *host = req->a_host;
345 struct rpc_clnt *clnt;
346 struct rpc_task_setup task_setup_data = {
347 .rpc_message = msg,
348 .callback_ops = tk_ops,
349 .callback_data = req,
350 .flags = RPC_TASK_ASYNC,
351 };
352
353 dprintk("lockd: call procedure %d on %s (async)\n",
354 (int)proc, host->h_name);
355
356 /* If we have no RPC client yet, create one. */
357 clnt = nlm_bind_host(host);
358 if (clnt == NULL)
359 goto out_err;
360 msg->rpc_proc = &clnt->cl_procinfo[proc];
361 task_setup_data.rpc_client = clnt;
362
363 /* bootstrap and kick off the async RPC call */
364 return rpc_run_task(&task_setup_data);
365out_err:
366 tk_ops->rpc_release(req);
367 return ERR_PTR(-ENOLCK);
368}
369
370static int nlm_do_async_call(struct nlm_rqst *req, u32 proc, struct rpc_message *msg, const struct rpc_call_ops *tk_ops)
371{
372 struct rpc_task *task;
373
374 task = __nlm_async_call(req, proc, msg, tk_ops);
375 if (IS_ERR(task))
376 return PTR_ERR(task);
377 rpc_put_task(task);
378 return 0;
379}
380
381/*
382 * NLM asynchronous call.
383 */
384int nlm_async_call(struct nlm_rqst *req, u32 proc, const struct rpc_call_ops *tk_ops)
385{
386 struct rpc_message msg = {
387 .rpc_argp = &req->a_args,
388 .rpc_resp = &req->a_res,
389 };
390 return nlm_do_async_call(req, proc, &msg, tk_ops);
391}
392
393int nlm_async_reply(struct nlm_rqst *req, u32 proc, const struct rpc_call_ops *tk_ops)
394{
395 struct rpc_message msg = {
396 .rpc_argp = &req->a_res,
397 };
398 return nlm_do_async_call(req, proc, &msg, tk_ops);
399}
400
401/*
402 * NLM client asynchronous call.
403 *
404 * Note that although the calls are asynchronous, and are therefore
405 * guaranteed to complete, we still always attempt to wait for
406 * completion in order to be able to correctly track the lock
407 * state.
408 */
409static int nlmclnt_async_call(const struct cred *cred, struct nlm_rqst *req, u32 proc, const struct rpc_call_ops *tk_ops)
410{
411 struct rpc_message msg = {
412 .rpc_argp = &req->a_args,
413 .rpc_resp = &req->a_res,
414 .rpc_cred = cred,
415 };
416 struct rpc_task *task;
417 int err;
418
419 task = __nlm_async_call(req, proc, &msg, tk_ops);
420 if (IS_ERR(task))
421 return PTR_ERR(task);
422 err = rpc_wait_for_completion_task(task);
423 rpc_put_task(task);
424 return err;
425}
426
427/*
428 * TEST for the presence of a conflicting lock
429 */
430static int
431nlmclnt_test(struct nlm_rqst *req, struct file_lock *fl)
432{
433 int status;
434
435 status = nlmclnt_call(nfs_file_cred(fl->fl_file), req, NLMPROC_TEST);
436 if (status < 0)
437 goto out;
438
439 switch (req->a_res.status) {
440 case nlm_granted:
441 fl->fl_type = F_UNLCK;
442 break;
443 case nlm_lck_denied:
444 /*
445 * Report the conflicting lock back to the application.
446 */
447 fl->fl_start = req->a_res.lock.fl.fl_start;
448 fl->fl_end = req->a_res.lock.fl.fl_end;
449 fl->fl_type = req->a_res.lock.fl.fl_type;
450 fl->fl_pid = -req->a_res.lock.fl.fl_pid;
451 break;
452 default:
453 status = nlm_stat_to_errno(req->a_res.status);
454 }
455out:
456 trace_nlmclnt_test(&req->a_args.lock,
457 (const struct sockaddr *)&req->a_host->h_addr,
458 req->a_host->h_addrlen, req->a_res.status);
459 nlmclnt_release_call(req);
460 return status;
461}
462
463static void nlmclnt_locks_copy_lock(struct file_lock *new, struct file_lock *fl)
464{
465 spin_lock(&fl->fl_u.nfs_fl.owner->host->h_lock);
466 new->fl_u.nfs_fl.state = fl->fl_u.nfs_fl.state;
467 new->fl_u.nfs_fl.owner = nlmclnt_get_lockowner(fl->fl_u.nfs_fl.owner);
468 list_add_tail(&new->fl_u.nfs_fl.list, &fl->fl_u.nfs_fl.owner->host->h_granted);
469 spin_unlock(&fl->fl_u.nfs_fl.owner->host->h_lock);
470}
471
472static void nlmclnt_locks_release_private(struct file_lock *fl)
473{
474 spin_lock(&fl->fl_u.nfs_fl.owner->host->h_lock);
475 list_del(&fl->fl_u.nfs_fl.list);
476 spin_unlock(&fl->fl_u.nfs_fl.owner->host->h_lock);
477 nlmclnt_put_lockowner(fl->fl_u.nfs_fl.owner);
478}
479
480static const struct file_lock_operations nlmclnt_lock_ops = {
481 .fl_copy_lock = nlmclnt_locks_copy_lock,
482 .fl_release_private = nlmclnt_locks_release_private,
483};
484
485static void nlmclnt_locks_init_private(struct file_lock *fl, struct nlm_host *host)
486{
487 fl->fl_u.nfs_fl.state = 0;
488 fl->fl_u.nfs_fl.owner = nlmclnt_find_lockowner(host, fl->fl_owner);
489 INIT_LIST_HEAD(&fl->fl_u.nfs_fl.list);
490 fl->fl_ops = &nlmclnt_lock_ops;
491}
492
493static int do_vfs_lock(struct file_lock *fl)
494{
495 return locks_lock_file_wait(fl->fl_file, fl);
496}
497
498/*
499 * LOCK: Try to create a lock
500 *
501 * Programmer Harassment Alert
502 *
503 * When given a blocking lock request in a sync RPC call, the HPUX lockd
504 * will faithfully return LCK_BLOCKED but never cares to notify us when
505 * the lock could be granted. This way, our local process could hang
506 * around forever waiting for the callback.
507 *
508 * Solution A: Implement busy-waiting
509 * Solution B: Use the async version of the call (NLM_LOCK_{MSG,RES})
510 *
511 * For now I am implementing solution A, because I hate the idea of
512 * re-implementing lockd for a third time in two months. The async
513 * calls shouldn't be too hard to do, however.
514 *
515 * This is one of the lovely things about standards in the NFS area:
516 * they're so soft and squishy you can't really blame HP for doing this.
517 */
518static int
519nlmclnt_lock(struct nlm_rqst *req, struct file_lock *fl)
520{
521 const struct cred *cred = nfs_file_cred(fl->fl_file);
522 struct nlm_host *host = req->a_host;
523 struct nlm_res *resp = &req->a_res;
524 struct nlm_wait block;
525 unsigned char fl_flags = fl->fl_flags;
526 unsigned char fl_type;
527 __be32 b_status;
528 int status = -ENOLCK;
529
530 if (nsm_monitor(host) < 0)
531 goto out;
532 req->a_args.state = nsm_local_state;
533
534 fl->fl_flags |= FL_ACCESS;
535 status = do_vfs_lock(fl);
536 fl->fl_flags = fl_flags;
537 if (status < 0)
538 goto out;
539
540 nlmclnt_prepare_block(&block, host, fl);
541again:
542 /*
543 * Initialise resp->status to a valid non-zero value,
544 * since 0 == nlm_lck_granted
545 */
546 resp->status = nlm_lck_blocked;
547
548 /*
549 * A GRANTED callback can come at any time -- even before the reply
550 * to the LOCK request arrives, so we queue the wait before
551 * requesting the lock.
552 */
553 nlmclnt_queue_block(&block);
554 for (;;) {
555 /* Reboot protection */
556 fl->fl_u.nfs_fl.state = host->h_state;
557 status = nlmclnt_call(cred, req, NLMPROC_LOCK);
558 if (status < 0)
559 break;
560 /* Did a reclaimer thread notify us of a server reboot? */
561 if (resp->status == nlm_lck_denied_grace_period)
562 continue;
563 if (resp->status != nlm_lck_blocked)
564 break;
565 /* Wait on an NLM blocking lock */
566 status = nlmclnt_wait(&block, req, NLMCLNT_POLL_TIMEOUT);
567 if (status < 0)
568 break;
569 if (block.b_status != nlm_lck_blocked)
570 break;
571 }
572 b_status = nlmclnt_dequeue_block(&block);
573 if (resp->status == nlm_lck_blocked)
574 resp->status = b_status;
575
576 /* if we were interrupted while blocking, then cancel the lock request
577 * and exit
578 */
579 if (resp->status == nlm_lck_blocked) {
580 if (!req->a_args.block)
581 goto out_unlock;
582 if (nlmclnt_cancel(host, req->a_args.block, fl) == 0)
583 goto out;
584 }
585
586 if (resp->status == nlm_granted) {
587 down_read(&host->h_rwsem);
588 /* Check whether or not the server has rebooted */
589 if (fl->fl_u.nfs_fl.state != host->h_state) {
590 up_read(&host->h_rwsem);
591 goto again;
592 }
593 /* Ensure the resulting lock will get added to granted list */
594 fl->fl_flags |= FL_SLEEP;
595 if (do_vfs_lock(fl) < 0)
596 printk(KERN_WARNING "%s: VFS is out of sync with lock manager!\n", __func__);
597 up_read(&host->h_rwsem);
598 fl->fl_flags = fl_flags;
599 status = 0;
600 }
601 if (status < 0)
602 goto out_unlock;
603 /*
604 * EAGAIN doesn't make sense for sleeping locks, and in some
605 * cases NLM_LCK_DENIED is returned for a permanent error. So
606 * turn it into an ENOLCK.
607 */
608 if (resp->status == nlm_lck_denied && (fl_flags & FL_SLEEP))
609 status = -ENOLCK;
610 else
611 status = nlm_stat_to_errno(resp->status);
612out:
613 trace_nlmclnt_lock(&req->a_args.lock,
614 (const struct sockaddr *)&req->a_host->h_addr,
615 req->a_host->h_addrlen, req->a_res.status);
616 nlmclnt_release_call(req);
617 return status;
618out_unlock:
619 /* Fatal error: ensure that we remove the lock altogether */
620 trace_nlmclnt_lock(&req->a_args.lock,
621 (const struct sockaddr *)&req->a_host->h_addr,
622 req->a_host->h_addrlen, req->a_res.status);
623 dprintk("lockd: lock attempt ended in fatal error.\n"
624 " Attempting to unlock.\n");
625 fl_type = fl->fl_type;
626 fl->fl_type = F_UNLCK;
627 down_read(&host->h_rwsem);
628 do_vfs_lock(fl);
629 up_read(&host->h_rwsem);
630 fl->fl_type = fl_type;
631 fl->fl_flags = fl_flags;
632 nlmclnt_async_call(cred, req, NLMPROC_UNLOCK, &nlmclnt_unlock_ops);
633 return status;
634}
635
636/*
637 * RECLAIM: Try to reclaim a lock
638 */
639int
640nlmclnt_reclaim(struct nlm_host *host, struct file_lock *fl,
641 struct nlm_rqst *req)
642{
643 int status;
644
645 memset(req, 0, sizeof(*req));
646 locks_init_lock(&req->a_args.lock.fl);
647 locks_init_lock(&req->a_res.lock.fl);
648 req->a_host = host;
649
650 /* Set up the argument struct */
651 nlmclnt_setlockargs(req, fl);
652 req->a_args.reclaim = 1;
653
654 status = nlmclnt_call(nfs_file_cred(fl->fl_file), req, NLMPROC_LOCK);
655 if (status >= 0 && req->a_res.status == nlm_granted)
656 return 0;
657
658 printk(KERN_WARNING "lockd: failed to reclaim lock for pid %d "
659 "(errno %d, status %d)\n", fl->fl_pid,
660 status, ntohl(req->a_res.status));
661
662 /*
663 * FIXME: This is a serious failure. We can
664 *
665 * a. Ignore the problem
666 * b. Send the owning process some signal (Linux doesn't have
667 * SIGLOST, though...)
668 * c. Retry the operation
669 *
670 * Until someone comes up with a simple implementation
671 * for b or c, I'll choose option a.
672 */
673
674 return -ENOLCK;
675}
676
677/*
678 * UNLOCK: remove an existing lock
679 */
680static int
681nlmclnt_unlock(struct nlm_rqst *req, struct file_lock *fl)
682{
683 struct nlm_host *host = req->a_host;
684 struct nlm_res *resp = &req->a_res;
685 int status;
686 unsigned char fl_flags = fl->fl_flags;
687
688 /*
689 * Note: the server is supposed to either grant us the unlock
690 * request, or to deny it with NLM_LCK_DENIED_GRACE_PERIOD. In either
691 * case, we want to unlock.
692 */
693 fl->fl_flags |= FL_EXISTS;
694 down_read(&host->h_rwsem);
695 status = do_vfs_lock(fl);
696 up_read(&host->h_rwsem);
697 fl->fl_flags = fl_flags;
698 if (status == -ENOENT) {
699 status = 0;
700 goto out;
701 }
702
703 refcount_inc(&req->a_count);
704 status = nlmclnt_async_call(nfs_file_cred(fl->fl_file), req,
705 NLMPROC_UNLOCK, &nlmclnt_unlock_ops);
706 if (status < 0)
707 goto out;
708
709 if (resp->status == nlm_granted)
710 goto out;
711
712 if (resp->status != nlm_lck_denied_nolocks)
713 printk("lockd: unexpected unlock status: %d\n",
714 ntohl(resp->status));
715 /* What to do now? I'm out of my depth... */
716 status = -ENOLCK;
717out:
718 trace_nlmclnt_unlock(&req->a_args.lock,
719 (const struct sockaddr *)&req->a_host->h_addr,
720 req->a_host->h_addrlen, req->a_res.status);
721 nlmclnt_release_call(req);
722 return status;
723}
724
725static void nlmclnt_unlock_prepare(struct rpc_task *task, void *data)
726{
727 struct nlm_rqst *req = data;
728 const struct nlmclnt_operations *nlmclnt_ops = req->a_host->h_nlmclnt_ops;
729 bool defer_call = false;
730
731 if (nlmclnt_ops && nlmclnt_ops->nlmclnt_unlock_prepare)
732 defer_call = nlmclnt_ops->nlmclnt_unlock_prepare(task, req->a_callback_data);
733
734 if (!defer_call)
735 rpc_call_start(task);
736}
737
738static void nlmclnt_unlock_callback(struct rpc_task *task, void *data)
739{
740 struct nlm_rqst *req = data;
741 u32 status = ntohl(req->a_res.status);
742
743 if (RPC_SIGNALLED(task))
744 goto die;
745
746 if (task->tk_status < 0) {
747 dprintk("lockd: unlock failed (err = %d)\n", -task->tk_status);
748 switch (task->tk_status) {
749 case -EACCES:
750 case -EIO:
751 goto die;
752 default:
753 goto retry_rebind;
754 }
755 }
756 if (status == NLM_LCK_DENIED_GRACE_PERIOD) {
757 rpc_delay(task, NLMCLNT_GRACE_WAIT);
758 goto retry_unlock;
759 }
760 if (status != NLM_LCK_GRANTED)
761 printk(KERN_WARNING "lockd: unexpected unlock status: %d\n", status);
762die:
763 return;
764 retry_rebind:
765 nlm_rebind_host(req->a_host);
766 retry_unlock:
767 rpc_restart_call(task);
768}
769
770static const struct rpc_call_ops nlmclnt_unlock_ops = {
771 .rpc_call_prepare = nlmclnt_unlock_prepare,
772 .rpc_call_done = nlmclnt_unlock_callback,
773 .rpc_release = nlmclnt_rpc_release,
774};
775
776/*
777 * Cancel a blocked lock request.
778 * We always use an async RPC call for this in order not to hang a
779 * process that has been Ctrl-C'ed.
780 */
781static int nlmclnt_cancel(struct nlm_host *host, int block, struct file_lock *fl)
782{
783 struct nlm_rqst *req;
784 int status;
785
786 dprintk("lockd: blocking lock attempt was interrupted by a signal.\n"
787 " Attempting to cancel lock.\n");
788
789 req = nlm_alloc_call(host);
790 if (!req)
791 return -ENOMEM;
792 req->a_flags = RPC_TASK_ASYNC;
793
794 nlmclnt_setlockargs(req, fl);
795 req->a_args.block = block;
796
797 refcount_inc(&req->a_count);
798 status = nlmclnt_async_call(nfs_file_cred(fl->fl_file), req,
799 NLMPROC_CANCEL, &nlmclnt_cancel_ops);
800 if (status == 0 && req->a_res.status == nlm_lck_denied)
801 status = -ENOLCK;
802 nlmclnt_release_call(req);
803 return status;
804}
805
806static void nlmclnt_cancel_callback(struct rpc_task *task, void *data)
807{
808 struct nlm_rqst *req = data;
809 u32 status = ntohl(req->a_res.status);
810
811 if (RPC_SIGNALLED(task))
812 goto die;
813
814 if (task->tk_status < 0) {
815 dprintk("lockd: CANCEL call error %d, retrying.\n",
816 task->tk_status);
817 goto retry_cancel;
818 }
819
820 switch (status) {
821 case NLM_LCK_GRANTED:
822 case NLM_LCK_DENIED_GRACE_PERIOD:
823 case NLM_LCK_DENIED:
824 /* Everything's good */
825 break;
826 case NLM_LCK_DENIED_NOLOCKS:
827 dprintk("lockd: CANCEL failed (server has no locks)\n");
828 goto retry_cancel;
829 default:
830 printk(KERN_NOTICE "lockd: weird return %d for CANCEL call\n",
831 status);
832 }
833
834die:
835 return;
836
837retry_cancel:
838 /* Don't ever retry more than 3 times */
839 if (req->a_retries++ >= NLMCLNT_MAX_RETRIES)
840 goto die;
841 nlm_rebind_host(req->a_host);
842 rpc_restart_call(task);
843 rpc_delay(task, 30 * HZ);
844}
845
846static const struct rpc_call_ops nlmclnt_cancel_ops = {
847 .rpc_call_done = nlmclnt_cancel_callback,
848 .rpc_release = nlmclnt_rpc_release,
849};
850
851/*
852 * Convert an NLM status code to a generic kernel errno
853 */
854static int
855nlm_stat_to_errno(__be32 status)
856{
857 switch(ntohl(status)) {
858 case NLM_LCK_GRANTED:
859 return 0;
860 case NLM_LCK_DENIED:
861 return -EAGAIN;
862 case NLM_LCK_DENIED_NOLOCKS:
863 case NLM_LCK_DENIED_GRACE_PERIOD:
864 return -ENOLCK;
865 case NLM_LCK_BLOCKED:
866 printk(KERN_NOTICE "lockd: unexpected status NLM_BLOCKED\n");
867 return -ENOLCK;
868#ifdef CONFIG_LOCKD_V4
869 case NLM_DEADLCK:
870 return -EDEADLK;
871 case NLM_ROFS:
872 return -EROFS;
873 case NLM_STALE_FH:
874 return -ESTALE;
875 case NLM_FBIG:
876 return -EOVERFLOW;
877 case NLM_FAILED:
878 return -ENOLCK;
879#endif
880 }
881 printk(KERN_NOTICE "lockd: unexpected server status %d\n",
882 ntohl(status));
883 return -ENOLCK;
884}