]> git.proxmox.com Git - mirror_ubuntu-bionic-kernel.git/blame - fs/lockd/svclock.c
Merge branch 'x86-kbuild-for-linus' of git://git.kernel.org/pub/scm/linux/kernel...
[mirror_ubuntu-bionic-kernel.git] / fs / lockd / svclock.c
CommitLineData
1da177e4
LT
1/*
2 * linux/fs/lockd/svclock.c
3 *
4 * Handling of server-side locks, mostly of the blocked variety.
5 * This is the ugliest part of lockd because we tread on very thin ice.
6 * GRANT and CANCEL calls may get stuck, meet in mid-flight, etc.
7 * IMNSHO introducing the grant callback into the NLM protocol was one
8 * of the worst ideas Sun ever had. Except maybe for the idea of doing
9 * NFS file locking at all.
10 *
11 * I'm trying hard to avoid race conditions by protecting most accesses
12 * to a file's list of blocked locks through a semaphore. The global
13 * list of blocked locks is not protected in this fashion however.
14 * Therefore, some functions (such as the RPC callback for the async grant
15 * call) move blocked locks towards the head of the list *while some other
16 * process might be traversing it*. This should not be a problem in
17 * practice, because this will only cause functions traversing the list
18 * to visit some blocks twice.
19 *
20 * Copyright (C) 1996, Olaf Kirch <okir@monad.swb.de>
21 */
22
1da177e4
LT
23#include <linux/types.h>
24#include <linux/errno.h>
25#include <linux/kernel.h>
26#include <linux/sched.h>
27#include <linux/smp_lock.h>
28#include <linux/sunrpc/clnt.h>
29#include <linux/sunrpc/svc.h>
30#include <linux/lockd/nlm.h>
31#include <linux/lockd/lockd.h>
d751a7cd 32#include <linux/kthread.h>
1da177e4
LT
33
34#define NLMDBG_FACILITY NLMDBG_SVCLOCK
35
36#ifdef CONFIG_LOCKD_V4
37#define nlm_deadlock nlm4_deadlock
38#else
39#define nlm_deadlock nlm_lck_denied
40#endif
41
6849c0ca 42static void nlmsvc_release_block(struct nlm_block *block);
1da177e4 43static void nlmsvc_insert_block(struct nlm_block *block, unsigned long);
68a2d76c 44static void nlmsvc_remove_block(struct nlm_block *block);
963d8fe5 45
5e1abf8c
TM
46static int nlmsvc_setgrantargs(struct nlm_rqst *call, struct nlm_lock *lock);
47static void nlmsvc_freegrantargs(struct nlm_rqst *call);
963d8fe5 48static const struct rpc_call_ops nlmsvc_grant_ops;
1da177e4
LT
49
50/*
51 * The list of blocked locks to retry
52 */
68a2d76c 53static LIST_HEAD(nlm_blocked);
1da177e4
LT
54
55/*
56 * Insert a blocked lock into the global list
57 */
58static void
59nlmsvc_insert_block(struct nlm_block *block, unsigned long when)
60{
68a2d76c
OK
61 struct nlm_block *b;
62 struct list_head *pos;
1da177e4
LT
63
64 dprintk("lockd: nlmsvc_insert_block(%p, %ld)\n", block, when);
68a2d76c
OK
65 if (list_empty(&block->b_list)) {
66 kref_get(&block->b_count);
67 } else {
68 list_del_init(&block->b_list);
69 }
70
71 pos = &nlm_blocked;
1da177e4
LT
72 if (when != NLM_NEVER) {
73 if ((when += jiffies) == NLM_NEVER)
74 when ++;
68a2d76c
OK
75 list_for_each(pos, &nlm_blocked) {
76 b = list_entry(pos, struct nlm_block, b_list);
77 if (time_after(b->b_when,when) || b->b_when == NLM_NEVER)
78 break;
79 }
80 /* On normal exit from the loop, pos == &nlm_blocked,
81 * so we will be adding to the end of the list - good
82 */
83 }
1da177e4 84
68a2d76c 85 list_add_tail(&block->b_list, pos);
1da177e4 86 block->b_when = when;
1da177e4
LT
87}
88
89/*
90 * Remove a block from the global list
91 */
68a2d76c 92static inline void
1da177e4
LT
93nlmsvc_remove_block(struct nlm_block *block)
94{
68a2d76c
OK
95 if (!list_empty(&block->b_list)) {
96 list_del_init(&block->b_list);
97 nlmsvc_release_block(block);
1da177e4 98 }
1da177e4
LT
99}
100
101/*
d9f6eb75 102 * Find a block for a given lock
1da177e4
LT
103 */
104static struct nlm_block *
d9f6eb75 105nlmsvc_lookup_block(struct nlm_file *file, struct nlm_lock *lock)
1da177e4 106{
68a2d76c 107 struct nlm_block *block;
1da177e4
LT
108 struct file_lock *fl;
109
110 dprintk("lockd: nlmsvc_lookup_block f=%p pd=%d %Ld-%Ld ty=%d\n",
111 file, lock->fl.fl_pid,
112 (long long)lock->fl.fl_start,
113 (long long)lock->fl.fl_end, lock->fl.fl_type);
68a2d76c 114 list_for_each_entry(block, &nlm_blocked, b_list) {
92737230 115 fl = &block->b_call->a_args.lock.fl;
1da177e4
LT
116 dprintk("lockd: check f=%p pd=%d %Ld-%Ld ty=%d cookie=%s\n",
117 block->b_file, fl->fl_pid,
118 (long long)fl->fl_start,
119 (long long)fl->fl_end, fl->fl_type,
92737230 120 nlmdbg_cookie2a(&block->b_call->a_args.cookie));
1da177e4 121 if (block->b_file == file && nlm_compare_locks(fl, &lock->fl)) {
6849c0ca 122 kref_get(&block->b_count);
1da177e4
LT
123 return block;
124 }
125 }
126
127 return NULL;
128}
129
130static inline int nlm_cookie_match(struct nlm_cookie *a, struct nlm_cookie *b)
131{
6d7bbbba 132 if (a->len != b->len)
1da177e4 133 return 0;
6d7bbbba 134 if (memcmp(a->data, b->data, a->len))
1da177e4
LT
135 return 0;
136 return 1;
137}
138
139/*
140 * Find a block with a given NLM cookie.
141 */
142static inline struct nlm_block *
39be4502 143nlmsvc_find_block(struct nlm_cookie *cookie)
1da177e4
LT
144{
145 struct nlm_block *block;
146
68a2d76c 147 list_for_each_entry(block, &nlm_blocked, b_list) {
39be4502 148 if (nlm_cookie_match(&block->b_call->a_args.cookie,cookie))
68a2d76c 149 goto found;
1da177e4
LT
150 }
151
68a2d76c
OK
152 return NULL;
153
154found:
39be4502 155 dprintk("nlmsvc_find_block(%s): block=%p\n", nlmdbg_cookie2a(cookie), block);
68a2d76c 156 kref_get(&block->b_count);
1da177e4
LT
157 return block;
158}
159
160/*
161 * Create a block and initialize it.
162 *
163 * Note: we explicitly set the cookie of the grant reply to that of
164 * the blocked lock request. The spec explicitly mentions that the client
165 * should _not_ rely on the callback containing the same cookie as the
166 * request, but (as I found out later) that's because some implementations
167 * do just this. Never mind the standards comittees, they support our
168 * logging industries.
39be4502
OK
169 *
170 * 10 years later: I hope we can safely ignore these old and broken
171 * clients by now. Let's fix this so we can uniquely identify an incoming
172 * GRANTED_RES message by cookie, without having to rely on the client's IP
173 * address. --okir
1da177e4 174 */
255129d1
TM
175static struct nlm_block *
176nlmsvc_create_block(struct svc_rqst *rqstp, struct nlm_host *host,
177 struct nlm_file *file, struct nlm_lock *lock,
178 struct nlm_cookie *cookie)
1da177e4
LT
179{
180 struct nlm_block *block;
92737230 181 struct nlm_rqst *call = NULL;
1da177e4 182
560de0e6 183 nlm_get_host(host);
92737230
TM
184 call = nlm_alloc_call(host);
185 if (call == NULL)
186 return NULL;
187
1da177e4 188 /* Allocate memory for block, and initialize arguments */
92737230
TM
189 block = kzalloc(sizeof(*block), GFP_KERNEL);
190 if (block == NULL)
1da177e4 191 goto failed;
6849c0ca 192 kref_init(&block->b_count);
68a2d76c
OK
193 INIT_LIST_HEAD(&block->b_list);
194 INIT_LIST_HEAD(&block->b_flist);
1da177e4 195
92737230 196 if (!nlmsvc_setgrantargs(call, lock))
1da177e4
LT
197 goto failed_free;
198
199 /* Set notifier function for VFS, and init args */
92737230
TM
200 call->a_args.lock.fl.fl_flags |= FL_SLEEP;
201 call->a_args.lock.fl.fl_lmops = &nlmsvc_lock_operations;
39be4502 202 nlmclnt_next_cookie(&call->a_args.cookie);
1da177e4
LT
203
204 dprintk("lockd: created block %p...\n", block);
205
206 /* Create and initialize the block */
207 block->b_daemon = rqstp->rq_server;
208 block->b_host = host;
209 block->b_file = file;
5ea0d750 210 block->b_fl = NULL;
d9f6eb75 211 file->f_count++;
1da177e4
LT
212
213 /* Add to file's list of blocks */
68a2d76c 214 list_add(&block->b_flist, &file->f_blocks);
1da177e4
LT
215
216 /* Set up RPC arguments for callback */
92737230 217 block->b_call = call;
1da177e4 218 call->a_flags = RPC_TASK_ASYNC;
92737230 219 call->a_block = block;
1da177e4
LT
220
221 return block;
222
223failed_free:
224 kfree(block);
225failed:
92737230 226 nlm_release_call(call);
1da177e4
LT
227 return NULL;
228}
229
230/*
3c61eecb 231 * Delete a block.
1da177e4
LT
232 * It is the caller's responsibility to check whether the file
233 * can be closed hereafter.
234 */
6849c0ca 235static int nlmsvc_unlink_block(struct nlm_block *block)
1da177e4 236{
09c7938c 237 int status;
6849c0ca 238 dprintk("lockd: unlinking block %p...\n", block);
1da177e4
LT
239
240 /* Remove block from list */
92737230 241 status = posix_unblock_lock(block->b_file->f_file, &block->b_call->a_args.lock.fl);
1da177e4 242 nlmsvc_remove_block(block);
6849c0ca
TM
243 return status;
244}
1da177e4 245
6849c0ca
TM
246static void nlmsvc_free_block(struct kref *kref)
247{
248 struct nlm_block *block = container_of(kref, struct nlm_block, b_count);
249 struct nlm_file *file = block->b_file;
6849c0ca
TM
250
251 dprintk("lockd: freeing block %p...\n", block);
1da177e4
LT
252
253 /* Remove block from file's list of blocks */
89e63ef6 254 mutex_lock(&file->f_mutex);
68a2d76c 255 list_del_init(&block->b_flist);
89e63ef6 256 mutex_unlock(&file->f_mutex);
1da177e4 257
92737230
TM
258 nlmsvc_freegrantargs(block->b_call);
259 nlm_release_call(block->b_call);
d9f6eb75 260 nlm_release_file(block->b_file);
0e4ac9d9 261 kfree(block->b_fl);
1da177e4 262 kfree(block);
6849c0ca
TM
263}
264
265static void nlmsvc_release_block(struct nlm_block *block)
266{
267 if (block != NULL)
268 kref_put(&block->b_count, nlmsvc_free_block);
1da177e4
LT
269}
270
f2af793d
OK
271/*
272 * Loop over all blocks and delete blocks held by
273 * a matching host.
274 */
275void nlmsvc_traverse_blocks(struct nlm_host *host,
276 struct nlm_file *file,
277 nlm_host_match_fn_t match)
d9f6eb75 278{
68a2d76c 279 struct nlm_block *block, *next;
d9f6eb75
TM
280
281restart:
89e63ef6 282 mutex_lock(&file->f_mutex);
68a2d76c 283 list_for_each_entry_safe(block, next, &file->f_blocks, b_flist) {
f2af793d 284 if (!match(block->b_host, host))
d9f6eb75 285 continue;
68a2d76c
OK
286 /* Do not destroy blocks that are not on
287 * the global retry list - why? */
288 if (list_empty(&block->b_list))
d9f6eb75
TM
289 continue;
290 kref_get(&block->b_count);
89e63ef6 291 mutex_unlock(&file->f_mutex);
d9f6eb75
TM
292 nlmsvc_unlink_block(block);
293 nlmsvc_release_block(block);
294 goto restart;
295 }
89e63ef6 296 mutex_unlock(&file->f_mutex);
d9f6eb75
TM
297}
298
5e1abf8c
TM
299/*
300 * Initialize arguments for GRANTED call. The nlm_rqst structure
301 * has been cleared already.
302 */
303static int nlmsvc_setgrantargs(struct nlm_rqst *call, struct nlm_lock *lock)
304{
305 locks_copy_lock(&call->a_args.lock.fl, &lock->fl);
306 memcpy(&call->a_args.lock.fh, &lock->fh, sizeof(call->a_args.lock.fh));
e9ff3990 307 call->a_args.lock.caller = utsname()->nodename;
5e1abf8c
TM
308 call->a_args.lock.oh.len = lock->oh.len;
309
310 /* set default data area */
311 call->a_args.lock.oh.data = call->a_owner;
312 call->a_args.lock.svid = lock->fl.fl_pid;
313
314 if (lock->oh.len > NLMCLNT_OHSIZE) {
315 void *data = kmalloc(lock->oh.len, GFP_KERNEL);
92737230 316 if (!data)
5e1abf8c 317 return 0;
5e1abf8c
TM
318 call->a_args.lock.oh.data = (u8 *) data;
319 }
320
321 memcpy(call->a_args.lock.oh.data, lock->oh.data, lock->oh.len);
322 return 1;
323}
324
325static void nlmsvc_freegrantargs(struct nlm_rqst *call)
326{
92737230 327 if (call->a_args.lock.oh.data != call->a_owner)
5e1abf8c 328 kfree(call->a_args.lock.oh.data);
5e1abf8c
TM
329}
330
2b36f412
ME
331/*
332 * Deferred lock request handling for non-blocking lock
333 */
ca5c8cde 334static __be32
2b36f412
ME
335nlmsvc_defer_lock_rqst(struct svc_rqst *rqstp, struct nlm_block *block)
336{
ca5c8cde 337 __be32 status = nlm_lck_denied_nolocks;
2b36f412
ME
338
339 block->b_flags |= B_QUEUED;
340
341 nlmsvc_insert_block(block, NLM_TIMEOUT);
342
343 block->b_cache_req = &rqstp->rq_chandle;
344 if (rqstp->rq_chandle.defer) {
345 block->b_deferred_req =
346 rqstp->rq_chandle.defer(block->b_cache_req);
347 if (block->b_deferred_req != NULL)
348 status = nlm_drop_reply;
349 }
350 dprintk("lockd: nlmsvc_defer_lock_rqst block %p flags %d status %d\n",
ca5c8cde 351 block, block->b_flags, ntohl(status));
2b36f412
ME
352
353 return status;
354}
355
1da177e4
LT
356/*
357 * Attempt to establish a lock, and if it can't be granted, block it
358 * if required.
359 */
52921e02 360__be32
1da177e4 361nlmsvc_lock(struct svc_rqst *rqstp, struct nlm_file *file,
6cde4de8 362 struct nlm_host *host, struct nlm_lock *lock, int wait,
b2b50289 363 struct nlm_cookie *cookie, int reclaim)
1da177e4 364{
f8120480 365 struct nlm_block *block = NULL;
1da177e4 366 int error;
52921e02 367 __be32 ret;
1da177e4
LT
368
369 dprintk("lockd: nlmsvc_lock(%s/%ld, ty=%d, pi=%d, %Ld-%Ld, bl=%d)\n",
225a719f
JS
370 file->f_file->f_path.dentry->d_inode->i_sb->s_id,
371 file->f_file->f_path.dentry->d_inode->i_ino,
1da177e4
LT
372 lock->fl.fl_type, lock->fl.fl_pid,
373 (long long)lock->fl.fl_start,
374 (long long)lock->fl.fl_end,
375 wait);
376
1da177e4 377 /* Lock file against concurrent access */
89e63ef6 378 mutex_lock(&file->f_mutex);
f8120480
ME
379 /* Get existing block (in case client is busy-waiting)
380 * or create new block
381 */
d9f6eb75 382 block = nlmsvc_lookup_block(file, lock);
09c7938c 383 if (block == NULL) {
560de0e6 384 block = nlmsvc_create_block(rqstp, host, file, lock, cookie);
f8120480
ME
385 ret = nlm_lck_denied_nolocks;
386 if (block == NULL)
387 goto out;
92737230 388 lock = &block->b_call->a_args.lock;
f8120480
ME
389 } else
390 lock->fl.fl_flags &= ~FL_SLEEP;
1da177e4 391
1a8322b2
ME
392 if (block->b_flags & B_QUEUED) {
393 dprintk("lockd: nlmsvc_lock deferred block %p flags %d\n",
394 block, block->b_flags);
395 if (block->b_granted) {
396 nlmsvc_unlink_block(block);
397 ret = nlm_granted;
398 goto out;
399 }
400 if (block->b_flags & B_TIMED_OUT) {
401 nlmsvc_unlink_block(block);
402 ret = nlm_lck_denied;
403 goto out;
404 }
405 ret = nlm_drop_reply;
406 goto out;
407 }
1da177e4 408
b2b50289
BF
409 if (locks_in_grace() && !reclaim) {
410 ret = nlm_lck_denied_grace_period;
411 goto out;
412 }
d22b1cff
BF
413 if (reclaim && !locks_in_grace()) {
414 ret = nlm_lck_denied_grace_period;
415 goto out;
416 }
b2b50289 417
1a8322b2
ME
418 if (!wait)
419 lock->fl.fl_flags &= ~FL_SLEEP;
420 error = vfs_lock_file(file->f_file, F_SETLK, &lock->fl, NULL);
421 lock->fl.fl_flags &= ~FL_SLEEP;
a85f193e 422
1a8322b2 423 dprintk("lockd: vfs_lock_file returned %d\n", error);
6d7bbbba 424 switch (error) {
1da177e4 425 case 0:
15dadef9
AA
426 ret = nlm_granted;
427 goto out;
09c7938c 428 case -EAGAIN:
e33d1ea6
MS
429 /*
430 * If this is a blocking request for an
431 * already pending lock request then we need
432 * to put it back on lockd's block list
433 */
434 if (wait)
435 break;
1a8322b2 436 ret = nlm_lck_denied;
e33d1ea6 437 goto out;
bde74e4b 438 case FILE_LOCK_DEFERRED:
1a8322b2
ME
439 if (wait)
440 break;
441 /* Filesystem lock operation is in progress
442 Add it to the queue waiting for callback */
443 ret = nlmsvc_defer_lock_rqst(rqstp, block);
444 goto out;
09c7938c 445 case -EDEADLK:
15dadef9
AA
446 ret = nlm_deadlock;
447 goto out;
1da177e4 448 default: /* includes ENOLCK */
15dadef9
AA
449 ret = nlm_lck_denied_nolocks;
450 goto out;
1da177e4
LT
451 }
452
09c7938c 453 ret = nlm_lck_blocked;
1da177e4
LT
454
455 /* Append to list of blocked */
f8120480 456 nlmsvc_insert_block(block, NLM_NEVER);
15dadef9 457out:
89e63ef6 458 mutex_unlock(&file->f_mutex);
6849c0ca 459 nlmsvc_release_block(block);
15dadef9
AA
460 dprintk("lockd: nlmsvc_lock returned %u\n", ret);
461 return ret;
1da177e4
LT
462}
463
464/*
465 * Test for presence of a conflicting lock.
466 */
52921e02 467__be32
85f3f1b3 468nlmsvc_testlock(struct svc_rqst *rqstp, struct nlm_file *file,
8f920d5e
JL
469 struct nlm_host *host, struct nlm_lock *lock,
470 struct nlm_lock *conflock, struct nlm_cookie *cookie)
1da177e4 471{
5ea0d750
ME
472 struct nlm_block *block = NULL;
473 int error;
474 __be32 ret;
475
1da177e4 476 dprintk("lockd: nlmsvc_testlock(%s/%ld, ty=%d, %Ld-%Ld)\n",
225a719f
JS
477 file->f_file->f_path.dentry->d_inode->i_sb->s_id,
478 file->f_file->f_path.dentry->d_inode->i_ino,
1da177e4
LT
479 lock->fl.fl_type,
480 (long long)lock->fl.fl_start,
481 (long long)lock->fl.fl_end);
482
5ea0d750
ME
483 /* Get existing block (in case client is busy-waiting) */
484 block = nlmsvc_lookup_block(file, lock);
485
486 if (block == NULL) {
487 struct file_lock *conf = kzalloc(sizeof(*conf), GFP_KERNEL);
488
489 if (conf == NULL)
490 return nlm_granted;
255129d1 491 block = nlmsvc_create_block(rqstp, host, file, lock, cookie);
5ea0d750
ME
492 if (block == NULL) {
493 kfree(conf);
494 return nlm_granted;
495 }
496 block->b_fl = conf;
497 }
498 if (block->b_flags & B_QUEUED) {
499 dprintk("lockd: nlmsvc_testlock deferred block %p flags %d fl %p\n",
500 block, block->b_flags, block->b_fl);
501 if (block->b_flags & B_TIMED_OUT) {
502 nlmsvc_unlink_block(block);
29dbf546
OD
503 ret = nlm_lck_denied;
504 goto out;
5ea0d750
ME
505 }
506 if (block->b_flags & B_GOT_CALLBACK) {
54ca95eb 507 nlmsvc_unlink_block(block);
5ea0d750
ME
508 if (block->b_fl != NULL
509 && block->b_fl->fl_type != F_UNLCK) {
510 lock->fl = *block->b_fl;
511 goto conf_lock;
29dbf546 512 } else {
29dbf546
OD
513 ret = nlm_granted;
514 goto out;
5ea0d750
ME
515 }
516 }
29dbf546
OD
517 ret = nlm_drop_reply;
518 goto out;
1da177e4
LT
519 }
520
b2b50289
BF
521 if (locks_in_grace()) {
522 ret = nlm_lck_denied_grace_period;
523 goto out;
524 }
5ea0d750 525 error = vfs_test_lock(file->f_file, &lock->fl);
bde74e4b 526 if (error == FILE_LOCK_DEFERRED) {
29dbf546
OD
527 ret = nlmsvc_defer_lock_rqst(rqstp, block);
528 goto out;
529 }
5ea0d750
ME
530 if (error) {
531 ret = nlm_lck_denied_nolocks;
532 goto out;
533 }
534 if (lock->fl.fl_type == F_UNLCK) {
535 ret = nlm_granted;
536 goto out;
537 }
538
539conf_lock:
540 dprintk("lockd: conflicting lock(ty=%d, %Ld-%Ld)\n",
541 lock->fl.fl_type, (long long)lock->fl.fl_start,
542 (long long)lock->fl.fl_end);
543 conflock->caller = "somehost"; /* FIXME */
544 conflock->len = strlen(conflock->caller);
545 conflock->oh.len = 0; /* don't return OH info */
546 conflock->svid = lock->fl.fl_pid;
547 conflock->fl.fl_type = lock->fl.fl_type;
548 conflock->fl.fl_start = lock->fl.fl_start;
549 conflock->fl.fl_end = lock->fl.fl_end;
550 ret = nlm_lck_denied;
551out:
552 if (block)
553 nlmsvc_release_block(block);
554 return ret;
1da177e4
LT
555}
556
557/*
558 * Remove a lock.
559 * This implies a CANCEL call: We send a GRANT_MSG, the client replies
560 * with a GRANT_RES call which gets lost, and calls UNLOCK immediately
561 * afterwards. In this case the block will still be there, and hence
562 * must be removed.
563 */
52921e02 564__be32
1da177e4
LT
565nlmsvc_unlock(struct nlm_file *file, struct nlm_lock *lock)
566{
567 int error;
568
569 dprintk("lockd: nlmsvc_unlock(%s/%ld, pi=%d, %Ld-%Ld)\n",
225a719f
JS
570 file->f_file->f_path.dentry->d_inode->i_sb->s_id,
571 file->f_file->f_path.dentry->d_inode->i_ino,
1da177e4
LT
572 lock->fl.fl_pid,
573 (long long)lock->fl.fl_start,
574 (long long)lock->fl.fl_end);
575
576 /* First, cancel any lock that might be there */
577 nlmsvc_cancel_blocked(file, lock);
578
579 lock->fl.fl_type = F_UNLCK;
1a8322b2 580 error = vfs_lock_file(file->f_file, F_SETLK, &lock->fl, NULL);
1da177e4
LT
581
582 return (error < 0)? nlm_lck_denied_nolocks : nlm_granted;
583}
584
585/*
586 * Cancel a previously blocked request.
587 *
588 * A cancel request always overrides any grant that may currently
589 * be in progress.
590 * The calling procedure must check whether the file can be closed.
591 */
52921e02 592__be32
1da177e4
LT
593nlmsvc_cancel_blocked(struct nlm_file *file, struct nlm_lock *lock)
594{
595 struct nlm_block *block;
64a318ee 596 int status = 0;
1da177e4
LT
597
598 dprintk("lockd: nlmsvc_cancel(%s/%ld, pi=%d, %Ld-%Ld)\n",
225a719f
JS
599 file->f_file->f_path.dentry->d_inode->i_sb->s_id,
600 file->f_file->f_path.dentry->d_inode->i_ino,
1da177e4
LT
601 lock->fl.fl_pid,
602 (long long)lock->fl.fl_start,
603 (long long)lock->fl.fl_end);
604
b2b50289
BF
605 if (locks_in_grace())
606 return nlm_lck_denied_grace_period;
607
89e63ef6 608 mutex_lock(&file->f_mutex);
d9f6eb75 609 block = nlmsvc_lookup_block(file, lock);
89e63ef6 610 mutex_unlock(&file->f_mutex);
d9f6eb75 611 if (block != NULL) {
1a8322b2
ME
612 vfs_cancel_lock(block->b_file->f_file,
613 &block->b_call->a_args.lock.fl);
6849c0ca
TM
614 status = nlmsvc_unlink_block(block);
615 nlmsvc_release_block(block);
616 }
64a318ee 617 return status ? nlm_lck_denied : nlm_granted;
1da177e4
LT
618}
619
0e4ac9d9
ME
620/*
621 * This is a callback from the filesystem for VFS file lock requests.
622 * It will be used if fl_grant is defined and the filesystem can not
623 * respond to the request immediately.
624 * For GETLK request it will copy the reply to the nlm_block.
625 * For SETLK or SETLKW request it will get the local posix lock.
626 * In all cases it will move the block to the head of nlm_blocked q where
627 * nlmsvc_retry_blocked() can send back a reply for SETLKW or revisit the
628 * deferred rpc for GETLK and SETLK.
629 */
630static void
631nlmsvc_update_deferred_block(struct nlm_block *block, struct file_lock *conf,
632 int result)
633{
634 block->b_flags |= B_GOT_CALLBACK;
635 if (result == 0)
636 block->b_granted = 1;
637 else
638 block->b_flags |= B_TIMED_OUT;
639 if (conf) {
0e4ac9d9 640 if (block->b_fl)
1a747ee0 641 __locks_copy_lock(block->b_fl, conf);
0e4ac9d9
ME
642 }
643}
644
645static int nlmsvc_grant_deferred(struct file_lock *fl, struct file_lock *conf,
646 int result)
647{
648 struct nlm_block *block;
649 int rc = -ENOENT;
650
651 lock_kernel();
652 list_for_each_entry(block, &nlm_blocked, b_list) {
653 if (nlm_compare_locks(&block->b_call->a_args.lock.fl, fl)) {
654 dprintk("lockd: nlmsvc_notify_blocked block %p flags %d\n",
655 block, block->b_flags);
656 if (block->b_flags & B_QUEUED) {
657 if (block->b_flags & B_TIMED_OUT) {
658 rc = -ENOLCK;
659 break;
660 }
661 nlmsvc_update_deferred_block(block, conf, result);
662 } else if (result == 0)
663 block->b_granted = 1;
664
665 nlmsvc_insert_block(block, 0);
666 svc_wake_up(block->b_daemon);
667 rc = 0;
668 break;
669 }
670 }
671 unlock_kernel();
672 if (rc == -ENOENT)
673 printk(KERN_WARNING "lockd: grant for unknown block\n");
674 return rc;
675}
676
1da177e4
LT
677/*
678 * Unblock a blocked lock request. This is a callback invoked from the
679 * VFS layer when a lock on which we blocked is removed.
680 *
681 * This function doesn't grant the blocked lock instantly, but rather moves
682 * the block to the head of nlm_blocked where it can be picked up by lockd.
683 */
684static void
685nlmsvc_notify_blocked(struct file_lock *fl)
686{
68a2d76c 687 struct nlm_block *block;
1da177e4
LT
688
689 dprintk("lockd: VFS unblock notification for block %p\n", fl);
68a2d76c 690 list_for_each_entry(block, &nlm_blocked, b_list) {
92737230 691 if (nlm_compare_locks(&block->b_call->a_args.lock.fl, fl)) {
1da177e4
LT
692 nlmsvc_insert_block(block, 0);
693 svc_wake_up(block->b_daemon);
694 return;
695 }
696 }
697
698 printk(KERN_WARNING "lockd: notification for unknown block!\n");
699}
700
701static int nlmsvc_same_owner(struct file_lock *fl1, struct file_lock *fl2)
702{
703 return fl1->fl_owner == fl2->fl_owner && fl1->fl_pid == fl2->fl_pid;
704}
705
706struct lock_manager_operations nlmsvc_lock_operations = {
707 .fl_compare_owner = nlmsvc_same_owner,
708 .fl_notify = nlmsvc_notify_blocked,
0e4ac9d9 709 .fl_grant = nlmsvc_grant_deferred,
1da177e4
LT
710};
711
712/*
713 * Try to claim a lock that was previously blocked.
714 *
715 * Note that we use both the RPC_GRANTED_MSG call _and_ an async
716 * RPC thread when notifying the client. This seems like overkill...
717 * Here's why:
718 * - we don't want to use a synchronous RPC thread, otherwise
719 * we might find ourselves hanging on a dead portmapper.
720 * - Some lockd implementations (e.g. HP) don't react to
721 * RPC_GRANTED calls; they seem to insist on RPC_GRANTED_MSG calls.
722 */
723static void
724nlmsvc_grant_blocked(struct nlm_block *block)
725{
726 struct nlm_file *file = block->b_file;
92737230 727 struct nlm_lock *lock = &block->b_call->a_args.lock;
1da177e4
LT
728 int error;
729
730 dprintk("lockd: grant blocked lock %p\n", block);
731
0e4ac9d9
ME
732 kref_get(&block->b_count);
733
1da177e4 734 /* Unlink block request from list */
6849c0ca 735 nlmsvc_unlink_block(block);
1da177e4
LT
736
737 /* If b_granted is true this means we've been here before.
738 * Just retry the grant callback, possibly refreshing the RPC
739 * binding */
740 if (block->b_granted) {
741 nlm_rebind_host(block->b_host);
742 goto callback;
743 }
744
745 /* Try the lock operation again */
09c7938c 746 lock->fl.fl_flags |= FL_SLEEP;
1a8322b2 747 error = vfs_lock_file(file->f_file, F_SETLK, &lock->fl, NULL);
09c7938c
TM
748 lock->fl.fl_flags &= ~FL_SLEEP;
749
5de0e502
AA
750 switch (error) {
751 case 0:
752 break;
bde74e4b 753 case FILE_LOCK_DEFERRED:
1a8322b2 754 dprintk("lockd: lock still blocked error %d\n", error);
1da177e4 755 nlmsvc_insert_block(block, NLM_NEVER);
0e4ac9d9 756 nlmsvc_release_block(block);
d9f6eb75 757 return;
5de0e502 758 default:
1da177e4 759 printk(KERN_WARNING "lockd: unexpected error %d in %s!\n",
8e24eea7 760 -error, __func__);
1da177e4 761 nlmsvc_insert_block(block, 10 * HZ);
0e4ac9d9 762 nlmsvc_release_block(block);
d9f6eb75 763 return;
1da177e4
LT
764 }
765
766callback:
767 /* Lock was granted by VFS. */
768 dprintk("lockd: GRANTing blocked lock.\n");
769 block->b_granted = 1;
1da177e4 770
9706501e
JL
771 /* keep block on the list, but don't reattempt until the RPC
772 * completes or the submission fails
773 */
774 nlmsvc_insert_block(block, NLM_NEVER);
1da177e4 775
9706501e
JL
776 /* Call the client -- use a soft RPC task since nlmsvc_retry_blocked
777 * will queue up a new one if this one times out
778 */
779 error = nlm_async_call(block->b_call, NLMPROC_GRANTED_MSG,
780 &nlmsvc_grant_ops);
781
782 /* RPC submission failed, wait a bit and retry */
783 if (error < 0)
784 nlmsvc_insert_block(block, 10 * HZ);
1da177e4
LT
785}
786
787/*
788 * This is the callback from the RPC layer when the NLM_GRANTED_MSG
789 * RPC call has succeeded or timed out.
790 * Like all RPC callbacks, it is invoked by the rpciod process, so it
791 * better not sleep. Therefore, we put the blocked lock on the nlm_blocked
792 * chain once more in order to have it removed by lockd itself (which can
793 * then sleep on the file semaphore without disrupting e.g. the nfs client).
794 */
963d8fe5 795static void nlmsvc_grant_callback(struct rpc_task *task, void *data)
1da177e4 796{
963d8fe5 797 struct nlm_rqst *call = data;
92737230 798 struct nlm_block *block = call->a_block;
1da177e4 799 unsigned long timeout;
1da177e4
LT
800
801 dprintk("lockd: GRANT_MSG RPC callback\n");
1da177e4 802
a86dc496 803 lock_kernel();
c64e80d5
JL
804 /* if the block is not on a list at this point then it has
805 * been invalidated. Don't try to requeue it.
806 *
807 * FIXME: it's possible that the block is removed from the list
808 * after this check but before the nlmsvc_insert_block. In that
809 * case it will be added back. Perhaps we need better locking
810 * for nlm_blocked?
811 */
812 if (list_empty(&block->b_list))
a86dc496 813 goto out;
c64e80d5 814
1da177e4
LT
815 /* Technically, we should down the file semaphore here. Since we
816 * move the block towards the head of the queue only, no harm
817 * can be done, though. */
818 if (task->tk_status < 0) {
819 /* RPC error: Re-insert for retransmission */
820 timeout = 10 * HZ;
1da177e4
LT
821 } else {
822 /* Call was successful, now wait for client callback */
823 timeout = 60 * HZ;
824 }
825 nlmsvc_insert_block(block, timeout);
826 svc_wake_up(block->b_daemon);
a86dc496
TM
827out:
828 unlock_kernel();
5e1abf8c
TM
829}
830
ec535ce1 831static void nlmsvc_grant_release(void *data)
5e1abf8c 832{
6041b791
TM
833 struct nlm_rqst *call = data;
834
a86dc496 835 lock_kernel();
6041b791 836 nlmsvc_release_block(call->a_block);
a86dc496 837 unlock_kernel();
1da177e4
LT
838}
839
963d8fe5
TM
840static const struct rpc_call_ops nlmsvc_grant_ops = {
841 .rpc_call_done = nlmsvc_grant_callback,
5e1abf8c 842 .rpc_release = nlmsvc_grant_release,
963d8fe5
TM
843};
844
1da177e4
LT
845/*
846 * We received a GRANT_RES callback. Try to find the corresponding
847 * block.
848 */
849void
e8c5c045 850nlmsvc_grant_reply(struct nlm_cookie *cookie, __be32 status)
1da177e4
LT
851{
852 struct nlm_block *block;
1da177e4 853
39be4502
OK
854 dprintk("grant_reply: looking for cookie %x, s=%d \n",
855 *(unsigned int *)(cookie->data), status);
856 if (!(block = nlmsvc_find_block(cookie)))
1da177e4 857 return;
1da177e4 858
f232142c 859 if (block) {
e8c5c045 860 if (status == nlm_lck_denied_grace_period) {
1da177e4
LT
861 /* Try again in a couple of seconds */
862 nlmsvc_insert_block(block, 10 * HZ);
1da177e4
LT
863 } else {
864 /* Lock is now held by client, or has been rejected.
865 * In both cases, the block should be removed. */
6849c0ca 866 nlmsvc_unlink_block(block);
1da177e4
LT
867 }
868 }
6849c0ca 869 nlmsvc_release_block(block);
1da177e4
LT
870}
871
0e4ac9d9
ME
872/* Helper function to handle retry of a deferred block.
873 * If it is a blocking lock, call grant_blocked.
874 * For a non-blocking lock or test lock, revisit the request.
875 */
876static void
877retry_deferred_block(struct nlm_block *block)
878{
879 if (!(block->b_flags & B_GOT_CALLBACK))
880 block->b_flags |= B_TIMED_OUT;
881 nlmsvc_insert_block(block, NLM_TIMEOUT);
882 dprintk("revisit block %p flags %d\n", block, block->b_flags);
883 if (block->b_deferred_req) {
884 block->b_deferred_req->revisit(block->b_deferred_req, 0);
885 block->b_deferred_req = NULL;
886 }
887}
888
1da177e4
LT
889/*
890 * Retry all blocked locks that have been notified. This is where lockd
891 * picks up locks that can be granted, or grant notifications that must
892 * be retransmitted.
893 */
894unsigned long
895nlmsvc_retry_blocked(void)
896{
68a2d76c
OK
897 unsigned long timeout = MAX_SCHEDULE_TIMEOUT;
898 struct nlm_block *block;
899
d751a7cd 900 while (!list_empty(&nlm_blocked) && !kthread_should_stop()) {
68a2d76c 901 block = list_entry(nlm_blocked.next, struct nlm_block, b_list);
1da177e4 902
1da177e4
LT
903 if (block->b_when == NLM_NEVER)
904 break;
6d7bbbba 905 if (time_after(block->b_when, jiffies)) {
68a2d76c 906 timeout = block->b_when - jiffies;
1da177e4 907 break;
68a2d76c
OK
908 }
909
f3d43c76
BF
910 dprintk("nlmsvc_retry_blocked(%p, when=%ld)\n",
911 block, block->b_when);
0e4ac9d9
ME
912 if (block->b_flags & B_QUEUED) {
913 dprintk("nlmsvc_retry_blocked delete block (%p, granted=%d, flags=%d)\n",
914 block, block->b_granted, block->b_flags);
915 retry_deferred_block(block);
916 } else
917 nlmsvc_grant_blocked(block);
1da177e4
LT
918 }
919
68a2d76c 920 return timeout;
1da177e4 921}