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