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b2441318 1// SPDX-License-Identifier: GPL-2.0
1da177e4
LT
2/*
3 * linux/fs/lockd/svclock.c
4 *
5 * Handling of server-side locks, mostly of the blocked variety.
6 * This is the ugliest part of lockd because we tread on very thin ice.
7 * GRANT and CANCEL calls may get stuck, meet in mid-flight, etc.
8 * IMNSHO introducing the grant callback into the NLM protocol was one
9 * of the worst ideas Sun ever had. Except maybe for the idea of doing
10 * NFS file locking at all.
11 *
12 * I'm trying hard to avoid race conditions by protecting most accesses
13 * to a file's list of blocked locks through a semaphore. The global
14 * list of blocked locks is not protected in this fashion however.
15 * Therefore, some functions (such as the RPC callback for the async grant
16 * call) move blocked locks towards the head of the list *while some other
17 * process might be traversing it*. This should not be a problem in
18 * practice, because this will only cause functions traversing the list
19 * to visit some blocks twice.
20 *
21 * Copyright (C) 1996, Olaf Kirch <okir@monad.swb.de>
22 */
23
1da177e4 24#include <linux/types.h>
5a0e3ad6 25#include <linux/slab.h>
1da177e4
LT
26#include <linux/errno.h>
27#include <linux/kernel.h>
28#include <linux/sched.h>
1da177e4 29#include <linux/sunrpc/clnt.h>
5ccb0066 30#include <linux/sunrpc/svc_xprt.h>
1da177e4
LT
31#include <linux/lockd/nlm.h>
32#include <linux/lockd/lockd.h>
d751a7cd 33#include <linux/kthread.h>
1da177e4
LT
34
35#define NLMDBG_FACILITY NLMDBG_SVCLOCK
36
37#ifdef CONFIG_LOCKD_V4
38#define nlm_deadlock nlm4_deadlock
39#else
40#define nlm_deadlock nlm_lck_denied
41#endif
42
6849c0ca 43static void nlmsvc_release_block(struct nlm_block *block);
1da177e4 44static void nlmsvc_insert_block(struct nlm_block *block, unsigned long);
68a2d76c 45static void nlmsvc_remove_block(struct nlm_block *block);
963d8fe5 46
5e1abf8c
TM
47static int nlmsvc_setgrantargs(struct nlm_rqst *call, struct nlm_lock *lock);
48static void nlmsvc_freegrantargs(struct nlm_rqst *call);
963d8fe5 49static const struct rpc_call_ops nlmsvc_grant_ops;
1da177e4
LT
50
51/*
52 * The list of blocked locks to retry
53 */
68a2d76c 54static LIST_HEAD(nlm_blocked);
f904be9c 55static DEFINE_SPINLOCK(nlm_blocked_lock);
1da177e4 56
10b89567 57#if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
ffa94db6
TM
58static const char *nlmdbg_cookie2a(const struct nlm_cookie *cookie)
59{
60 /*
3c519914
JL
61 * We can get away with a static buffer because this is only called
62 * from lockd, which is single-threaded.
ffa94db6
TM
63 */
64 static char buf[2*NLM_MAXCOOKIELEN+1];
65 unsigned int i, len = sizeof(buf);
66 char *p = buf;
67
68 len--; /* allow for trailing \0 */
69 if (len < 3)
70 return "???";
71 for (i = 0 ; i < cookie->len ; i++) {
72 if (len < 2) {
73 strcpy(p-3, "...");
74 break;
75 }
76 sprintf(p, "%02x", cookie->data[i]);
77 p += 2;
78 len -= 2;
79 }
80 *p = '\0';
81
82 return buf;
83}
84#endif
85
1da177e4
LT
86/*
87 * Insert a blocked lock into the global list
88 */
89static void
f904be9c 90nlmsvc_insert_block_locked(struct nlm_block *block, unsigned long when)
1da177e4 91{
68a2d76c
OK
92 struct nlm_block *b;
93 struct list_head *pos;
1da177e4
LT
94
95 dprintk("lockd: nlmsvc_insert_block(%p, %ld)\n", block, when);
68a2d76c
OK
96 if (list_empty(&block->b_list)) {
97 kref_get(&block->b_count);
98 } else {
99 list_del_init(&block->b_list);
100 }
101
102 pos = &nlm_blocked;
1da177e4
LT
103 if (when != NLM_NEVER) {
104 if ((when += jiffies) == NLM_NEVER)
105 when ++;
68a2d76c
OK
106 list_for_each(pos, &nlm_blocked) {
107 b = list_entry(pos, struct nlm_block, b_list);
108 if (time_after(b->b_when,when) || b->b_when == NLM_NEVER)
109 break;
110 }
111 /* On normal exit from the loop, pos == &nlm_blocked,
112 * so we will be adding to the end of the list - good
113 */
114 }
1da177e4 115
68a2d76c 116 list_add_tail(&block->b_list, pos);
1da177e4 117 block->b_when = when;
1da177e4
LT
118}
119
f904be9c
BS
120static void nlmsvc_insert_block(struct nlm_block *block, unsigned long when)
121{
122 spin_lock(&nlm_blocked_lock);
123 nlmsvc_insert_block_locked(block, when);
124 spin_unlock(&nlm_blocked_lock);
125}
126
1da177e4
LT
127/*
128 * Remove a block from the global list
129 */
68a2d76c 130static inline void
1da177e4
LT
131nlmsvc_remove_block(struct nlm_block *block)
132{
68a2d76c 133 if (!list_empty(&block->b_list)) {
f904be9c 134 spin_lock(&nlm_blocked_lock);
68a2d76c 135 list_del_init(&block->b_list);
f904be9c 136 spin_unlock(&nlm_blocked_lock);
68a2d76c 137 nlmsvc_release_block(block);
1da177e4 138 }
1da177e4
LT
139}
140
141/*
d9f6eb75 142 * Find a block for a given lock
1da177e4
LT
143 */
144static struct nlm_block *
d9f6eb75 145nlmsvc_lookup_block(struct nlm_file *file, struct nlm_lock *lock)
1da177e4 146{
68a2d76c 147 struct nlm_block *block;
1da177e4
LT
148 struct file_lock *fl;
149
150 dprintk("lockd: nlmsvc_lookup_block f=%p pd=%d %Ld-%Ld ty=%d\n",
151 file, lock->fl.fl_pid,
152 (long long)lock->fl.fl_start,
153 (long long)lock->fl.fl_end, lock->fl.fl_type);
68a2d76c 154 list_for_each_entry(block, &nlm_blocked, b_list) {
92737230 155 fl = &block->b_call->a_args.lock.fl;
1da177e4
LT
156 dprintk("lockd: check f=%p pd=%d %Ld-%Ld ty=%d cookie=%s\n",
157 block->b_file, fl->fl_pid,
158 (long long)fl->fl_start,
159 (long long)fl->fl_end, fl->fl_type,
92737230 160 nlmdbg_cookie2a(&block->b_call->a_args.cookie));
1da177e4 161 if (block->b_file == file && nlm_compare_locks(fl, &lock->fl)) {
6849c0ca 162 kref_get(&block->b_count);
1da177e4
LT
163 return block;
164 }
165 }
166
167 return NULL;
168}
169
170static inline int nlm_cookie_match(struct nlm_cookie *a, struct nlm_cookie *b)
171{
6d7bbbba 172 if (a->len != b->len)
1da177e4 173 return 0;
6d7bbbba 174 if (memcmp(a->data, b->data, a->len))
1da177e4
LT
175 return 0;
176 return 1;
177}
178
179/*
180 * Find a block with a given NLM cookie.
181 */
182static inline struct nlm_block *
39be4502 183nlmsvc_find_block(struct nlm_cookie *cookie)
1da177e4
LT
184{
185 struct nlm_block *block;
186
68a2d76c 187 list_for_each_entry(block, &nlm_blocked, b_list) {
39be4502 188 if (nlm_cookie_match(&block->b_call->a_args.cookie,cookie))
68a2d76c 189 goto found;
1da177e4
LT
190 }
191
68a2d76c
OK
192 return NULL;
193
194found:
39be4502 195 dprintk("nlmsvc_find_block(%s): block=%p\n", nlmdbg_cookie2a(cookie), block);
68a2d76c 196 kref_get(&block->b_count);
1da177e4
LT
197 return block;
198}
199
200/*
201 * Create a block and initialize it.
202 *
203 * Note: we explicitly set the cookie of the grant reply to that of
204 * the blocked lock request. The spec explicitly mentions that the client
205 * should _not_ rely on the callback containing the same cookie as the
206 * request, but (as I found out later) that's because some implementations
207 * do just this. Never mind the standards comittees, they support our
208 * logging industries.
39be4502
OK
209 *
210 * 10 years later: I hope we can safely ignore these old and broken
211 * clients by now. Let's fix this so we can uniquely identify an incoming
212 * GRANTED_RES message by cookie, without having to rely on the client's IP
213 * address. --okir
1da177e4 214 */
255129d1
TM
215static struct nlm_block *
216nlmsvc_create_block(struct svc_rqst *rqstp, struct nlm_host *host,
217 struct nlm_file *file, struct nlm_lock *lock,
218 struct nlm_cookie *cookie)
1da177e4
LT
219{
220 struct nlm_block *block;
92737230 221 struct nlm_rqst *call = NULL;
1da177e4 222
92737230
TM
223 call = nlm_alloc_call(host);
224 if (call == NULL)
225 return NULL;
226
1da177e4 227 /* Allocate memory for block, and initialize arguments */
92737230
TM
228 block = kzalloc(sizeof(*block), GFP_KERNEL);
229 if (block == NULL)
1da177e4 230 goto failed;
6849c0ca 231 kref_init(&block->b_count);
68a2d76c
OK
232 INIT_LIST_HEAD(&block->b_list);
233 INIT_LIST_HEAD(&block->b_flist);
1da177e4 234
92737230 235 if (!nlmsvc_setgrantargs(call, lock))
1da177e4
LT
236 goto failed_free;
237
238 /* Set notifier function for VFS, and init args */
92737230
TM
239 call->a_args.lock.fl.fl_flags |= FL_SLEEP;
240 call->a_args.lock.fl.fl_lmops = &nlmsvc_lock_operations;
39be4502 241 nlmclnt_next_cookie(&call->a_args.cookie);
1da177e4
LT
242
243 dprintk("lockd: created block %p...\n", block);
244
245 /* Create and initialize the block */
246 block->b_daemon = rqstp->rq_server;
247 block->b_host = host;
248 block->b_file = file;
d9f6eb75 249 file->f_count++;
1da177e4
LT
250
251 /* Add to file's list of blocks */
68a2d76c 252 list_add(&block->b_flist, &file->f_blocks);
1da177e4
LT
253
254 /* Set up RPC arguments for callback */
92737230 255 block->b_call = call;
1da177e4 256 call->a_flags = RPC_TASK_ASYNC;
92737230 257 call->a_block = block;
1da177e4
LT
258
259 return block;
260
261failed_free:
262 kfree(block);
263failed:
7db836d4 264 nlmsvc_release_call(call);
1da177e4
LT
265 return NULL;
266}
267
268/*
3c61eecb 269 * Delete a block.
1da177e4
LT
270 * It is the caller's responsibility to check whether the file
271 * can be closed hereafter.
272 */
6849c0ca 273static int nlmsvc_unlink_block(struct nlm_block *block)
1da177e4 274{
09c7938c 275 int status;
6849c0ca 276 dprintk("lockd: unlinking block %p...\n", block);
1da177e4
LT
277
278 /* Remove block from list */
cb03f94f 279 status = locks_delete_block(&block->b_call->a_args.lock.fl);
1da177e4 280 nlmsvc_remove_block(block);
6849c0ca
TM
281 return status;
282}
1da177e4 283
6849c0ca
TM
284static void nlmsvc_free_block(struct kref *kref)
285{
286 struct nlm_block *block = container_of(kref, struct nlm_block, b_count);
287 struct nlm_file *file = block->b_file;
6849c0ca
TM
288
289 dprintk("lockd: freeing block %p...\n", block);
1da177e4
LT
290
291 /* Remove block from file's list of blocks */
68a2d76c 292 list_del_init(&block->b_flist);
89e63ef6 293 mutex_unlock(&file->f_mutex);
1da177e4 294
92737230 295 nlmsvc_freegrantargs(block->b_call);
7db836d4 296 nlmsvc_release_call(block->b_call);
d9f6eb75 297 nlm_release_file(block->b_file);
1da177e4 298 kfree(block);
6849c0ca
TM
299}
300
301static void nlmsvc_release_block(struct nlm_block *block)
302{
303 if (block != NULL)
c5aa1e55 304 kref_put_mutex(&block->b_count, nlmsvc_free_block, &block->b_file->f_mutex);
1da177e4
LT
305}
306
f2af793d
OK
307/*
308 * Loop over all blocks and delete blocks held by
309 * a matching host.
310 */
311void nlmsvc_traverse_blocks(struct nlm_host *host,
312 struct nlm_file *file,
313 nlm_host_match_fn_t match)
d9f6eb75 314{
68a2d76c 315 struct nlm_block *block, *next;
d9f6eb75
TM
316
317restart:
89e63ef6 318 mutex_lock(&file->f_mutex);
68a2d76c 319 list_for_each_entry_safe(block, next, &file->f_blocks, b_flist) {
f2af793d 320 if (!match(block->b_host, host))
d9f6eb75 321 continue;
68a2d76c
OK
322 /* Do not destroy blocks that are not on
323 * the global retry list - why? */
324 if (list_empty(&block->b_list))
d9f6eb75
TM
325 continue;
326 kref_get(&block->b_count);
89e63ef6 327 mutex_unlock(&file->f_mutex);
d9f6eb75
TM
328 nlmsvc_unlink_block(block);
329 nlmsvc_release_block(block);
330 goto restart;
331 }
89e63ef6 332 mutex_unlock(&file->f_mutex);
d9f6eb75
TM
333}
334
89e0edfb
BC
335static struct nlm_lockowner *
336nlmsvc_get_lockowner(struct nlm_lockowner *lockowner)
337{
338 refcount_inc(&lockowner->count);
339 return lockowner;
340}
341
342static void nlmsvc_put_lockowner(struct nlm_lockowner *lockowner)
343{
344 if (!refcount_dec_and_lock(&lockowner->count, &lockowner->host->h_lock))
345 return;
346 list_del(&lockowner->list);
347 spin_unlock(&lockowner->host->h_lock);
348 nlmsvc_release_host(lockowner->host);
349 kfree(lockowner);
350}
351
352static struct nlm_lockowner *__nlmsvc_find_lockowner(struct nlm_host *host, pid_t pid)
353{
354 struct nlm_lockowner *lockowner;
355 list_for_each_entry(lockowner, &host->h_lockowners, list) {
356 if (lockowner->pid != pid)
357 continue;
358 return nlmsvc_get_lockowner(lockowner);
359 }
360 return NULL;
361}
362
363static struct nlm_lockowner *nlmsvc_find_lockowner(struct nlm_host *host, pid_t pid)
364{
365 struct nlm_lockowner *res, *new = NULL;
366
367 spin_lock(&host->h_lock);
368 res = __nlmsvc_find_lockowner(host, pid);
369
370 if (res == NULL) {
371 spin_unlock(&host->h_lock);
372 new = kmalloc(sizeof(*res), GFP_KERNEL);
373 spin_lock(&host->h_lock);
374 res = __nlmsvc_find_lockowner(host, pid);
375 if (res == NULL && new != NULL) {
376 res = new;
377 /* fs/locks.c will manage the refcount through lock_ops */
378 refcount_set(&new->count, 1);
379 new->pid = pid;
380 new->host = nlm_get_host(host);
381 list_add(&new->list, &host->h_lockowners);
382 new = NULL;
383 }
384 }
385
386 spin_unlock(&host->h_lock);
387 kfree(new);
388 return res;
389}
390
391void
392nlmsvc_release_lockowner(struct nlm_lock *lock)
393{
394 if (lock->fl.fl_owner)
395 nlmsvc_put_lockowner(lock->fl.fl_owner);
396}
397
398static void nlmsvc_locks_copy_lock(struct file_lock *new, struct file_lock *fl)
399{
400 struct nlm_lockowner *nlm_lo = (struct nlm_lockowner *)fl->fl_owner;
401 new->fl_owner = nlmsvc_get_lockowner(nlm_lo);
402}
403
404static void nlmsvc_locks_release_private(struct file_lock *fl)
405{
406 nlmsvc_put_lockowner((struct nlm_lockowner *)fl->fl_owner);
407}
408
291adeb2 409static const struct file_lock_operations nlmsvc_lock_ops = {
89e0edfb
BC
410 .fl_copy_lock = nlmsvc_locks_copy_lock,
411 .fl_release_private = nlmsvc_locks_release_private,
412};
413
414void nlmsvc_locks_init_private(struct file_lock *fl, struct nlm_host *host,
415 pid_t pid)
416{
417 fl->fl_owner = nlmsvc_find_lockowner(host, pid);
418 if (fl->fl_owner != NULL)
419 fl->fl_ops = &nlmsvc_lock_ops;
420}
421
5e1abf8c
TM
422/*
423 * Initialize arguments for GRANTED call. The nlm_rqst structure
424 * has been cleared already.
425 */
426static int nlmsvc_setgrantargs(struct nlm_rqst *call, struct nlm_lock *lock)
427{
428 locks_copy_lock(&call->a_args.lock.fl, &lock->fl);
429 memcpy(&call->a_args.lock.fh, &lock->fh, sizeof(call->a_args.lock.fh));
e9ff3990 430 call->a_args.lock.caller = utsname()->nodename;
5e1abf8c
TM
431 call->a_args.lock.oh.len = lock->oh.len;
432
433 /* set default data area */
434 call->a_args.lock.oh.data = call->a_owner;
646d73e9 435 call->a_args.lock.svid = ((struct nlm_lockowner *)lock->fl.fl_owner)->pid;
5e1abf8c
TM
436
437 if (lock->oh.len > NLMCLNT_OHSIZE) {
438 void *data = kmalloc(lock->oh.len, GFP_KERNEL);
92737230 439 if (!data)
5e1abf8c 440 return 0;
5e1abf8c
TM
441 call->a_args.lock.oh.data = (u8 *) data;
442 }
443
444 memcpy(call->a_args.lock.oh.data, lock->oh.data, lock->oh.len);
445 return 1;
446}
447
448static void nlmsvc_freegrantargs(struct nlm_rqst *call)
449{
92737230 450 if (call->a_args.lock.oh.data != call->a_owner)
5e1abf8c 451 kfree(call->a_args.lock.oh.data);
a9e61e25
FB
452
453 locks_release_private(&call->a_args.lock.fl);
5e1abf8c
TM
454}
455
2b36f412
ME
456/*
457 * Deferred lock request handling for non-blocking lock
458 */
ca5c8cde 459static __be32
2b36f412
ME
460nlmsvc_defer_lock_rqst(struct svc_rqst *rqstp, struct nlm_block *block)
461{
ca5c8cde 462 __be32 status = nlm_lck_denied_nolocks;
2b36f412
ME
463
464 block->b_flags |= B_QUEUED;
465
466 nlmsvc_insert_block(block, NLM_TIMEOUT);
467
468 block->b_cache_req = &rqstp->rq_chandle;
469 if (rqstp->rq_chandle.defer) {
470 block->b_deferred_req =
471 rqstp->rq_chandle.defer(block->b_cache_req);
472 if (block->b_deferred_req != NULL)
473 status = nlm_drop_reply;
474 }
475 dprintk("lockd: nlmsvc_defer_lock_rqst block %p flags %d status %d\n",
ca5c8cde 476 block, block->b_flags, ntohl(status));
2b36f412
ME
477
478 return status;
479}
480
1da177e4
LT
481/*
482 * Attempt to establish a lock, and if it can't be granted, block it
483 * if required.
484 */
52921e02 485__be32
1da177e4 486nlmsvc_lock(struct svc_rqst *rqstp, struct nlm_file *file,
6cde4de8 487 struct nlm_host *host, struct nlm_lock *lock, int wait,
b2b50289 488 struct nlm_cookie *cookie, int reclaim)
1da177e4 489{
f8120480 490 struct nlm_block *block = NULL;
1da177e4 491 int error;
52921e02 492 __be32 ret;
1da177e4
LT
493
494 dprintk("lockd: nlmsvc_lock(%s/%ld, ty=%d, pi=%d, %Ld-%Ld, bl=%d)\n",
64bed6cb
AG
495 locks_inode(file->f_file)->i_sb->s_id,
496 locks_inode(file->f_file)->i_ino,
1da177e4
LT
497 lock->fl.fl_type, lock->fl.fl_pid,
498 (long long)lock->fl.fl_start,
499 (long long)lock->fl.fl_end,
500 wait);
501
1da177e4 502 /* Lock file against concurrent access */
89e63ef6 503 mutex_lock(&file->f_mutex);
f8120480
ME
504 /* Get existing block (in case client is busy-waiting)
505 * or create new block
506 */
d9f6eb75 507 block = nlmsvc_lookup_block(file, lock);
09c7938c 508 if (block == NULL) {
560de0e6 509 block = nlmsvc_create_block(rqstp, host, file, lock, cookie);
f8120480
ME
510 ret = nlm_lck_denied_nolocks;
511 if (block == NULL)
512 goto out;
92737230 513 lock = &block->b_call->a_args.lock;
f8120480
ME
514 } else
515 lock->fl.fl_flags &= ~FL_SLEEP;
1da177e4 516
1a8322b2
ME
517 if (block->b_flags & B_QUEUED) {
518 dprintk("lockd: nlmsvc_lock deferred block %p flags %d\n",
519 block, block->b_flags);
520 if (block->b_granted) {
521 nlmsvc_unlink_block(block);
522 ret = nlm_granted;
523 goto out;
524 }
525 if (block->b_flags & B_TIMED_OUT) {
526 nlmsvc_unlink_block(block);
527 ret = nlm_lck_denied;
528 goto out;
529 }
530 ret = nlm_drop_reply;
531 goto out;
532 }
1da177e4 533
5ccb0066 534 if (locks_in_grace(SVC_NET(rqstp)) && !reclaim) {
b2b50289
BF
535 ret = nlm_lck_denied_grace_period;
536 goto out;
537 }
5ccb0066 538 if (reclaim && !locks_in_grace(SVC_NET(rqstp))) {
d22b1cff
BF
539 ret = nlm_lck_denied_grace_period;
540 goto out;
541 }
b2b50289 542
1a8322b2
ME
543 if (!wait)
544 lock->fl.fl_flags &= ~FL_SLEEP;
545 error = vfs_lock_file(file->f_file, F_SETLK, &lock->fl, NULL);
546 lock->fl.fl_flags &= ~FL_SLEEP;
a85f193e 547
1a8322b2 548 dprintk("lockd: vfs_lock_file returned %d\n", error);
6d7bbbba 549 switch (error) {
1da177e4 550 case 0:
15dadef9
AA
551 ret = nlm_granted;
552 goto out;
09c7938c 553 case -EAGAIN:
e33d1ea6
MS
554 /*
555 * If this is a blocking request for an
556 * already pending lock request then we need
557 * to put it back on lockd's block list
558 */
559 if (wait)
560 break;
1a8322b2 561 ret = nlm_lck_denied;
e33d1ea6 562 goto out;
bde74e4b 563 case FILE_LOCK_DEFERRED:
1a8322b2
ME
564 if (wait)
565 break;
566 /* Filesystem lock operation is in progress
567 Add it to the queue waiting for callback */
568 ret = nlmsvc_defer_lock_rqst(rqstp, block);
569 goto out;
09c7938c 570 case -EDEADLK:
15dadef9
AA
571 ret = nlm_deadlock;
572 goto out;
1da177e4 573 default: /* includes ENOLCK */
15dadef9
AA
574 ret = nlm_lck_denied_nolocks;
575 goto out;
1da177e4
LT
576 }
577
09c7938c 578 ret = nlm_lck_blocked;
1da177e4
LT
579
580 /* Append to list of blocked */
f8120480 581 nlmsvc_insert_block(block, NLM_NEVER);
15dadef9 582out:
89e63ef6 583 mutex_unlock(&file->f_mutex);
6849c0ca 584 nlmsvc_release_block(block);
15dadef9
AA
585 dprintk("lockd: nlmsvc_lock returned %u\n", ret);
586 return ret;
1da177e4
LT
587}
588
589/*
590 * Test for presence of a conflicting lock.
591 */
52921e02 592__be32
85f3f1b3 593nlmsvc_testlock(struct svc_rqst *rqstp, struct nlm_file *file,
8f920d5e
JL
594 struct nlm_host *host, struct nlm_lock *lock,
595 struct nlm_lock *conflock, struct nlm_cookie *cookie)
1da177e4 596{
5ea0d750
ME
597 int error;
598 __be32 ret;
89e0edfb 599 struct nlm_lockowner *test_owner;
5ea0d750 600
1da177e4 601 dprintk("lockd: nlmsvc_testlock(%s/%ld, ty=%d, %Ld-%Ld)\n",
64bed6cb
AG
602 locks_inode(file->f_file)->i_sb->s_id,
603 locks_inode(file->f_file)->i_ino,
1da177e4
LT
604 lock->fl.fl_type,
605 (long long)lock->fl.fl_start,
606 (long long)lock->fl.fl_end);
607
5ccb0066 608 if (locks_in_grace(SVC_NET(rqstp))) {
b2b50289
BF
609 ret = nlm_lck_denied_grace_period;
610 goto out;
611 }
09802fd2 612
89e0edfb
BC
613 /* If there's a conflicting lock, remember to clean up the test lock */
614 test_owner = (struct nlm_lockowner *)lock->fl.fl_owner;
615
5ea0d750 616 error = vfs_test_lock(file->f_file, &lock->fl);
5ea0d750 617 if (error) {
09802fd2
JL
618 /* We can't currently deal with deferred test requests */
619 if (error == FILE_LOCK_DEFERRED)
620 WARN_ON_ONCE(1);
621
5ea0d750
ME
622 ret = nlm_lck_denied_nolocks;
623 goto out;
624 }
09802fd2 625
5ea0d750
ME
626 if (lock->fl.fl_type == F_UNLCK) {
627 ret = nlm_granted;
628 goto out;
629 }
630
5ea0d750
ME
631 dprintk("lockd: conflicting lock(ty=%d, %Ld-%Ld)\n",
632 lock->fl.fl_type, (long long)lock->fl.fl_start,
633 (long long)lock->fl.fl_end);
634 conflock->caller = "somehost"; /* FIXME */
635 conflock->len = strlen(conflock->caller);
636 conflock->oh.len = 0; /* don't return OH info */
646d73e9 637 conflock->svid = ((struct nlm_lockowner *)lock->fl.fl_owner)->pid;
5ea0d750
ME
638 conflock->fl.fl_type = lock->fl.fl_type;
639 conflock->fl.fl_start = lock->fl.fl_start;
640 conflock->fl.fl_end = lock->fl.fl_end;
f328296e 641 locks_release_private(&lock->fl);
89e0edfb
BC
642
643 /* Clean up the test lock */
644 lock->fl.fl_owner = NULL;
645 nlmsvc_put_lockowner(test_owner);
646
5ea0d750
ME
647 ret = nlm_lck_denied;
648out:
5ea0d750 649 return ret;
1da177e4
LT
650}
651
652/*
653 * Remove a lock.
654 * This implies a CANCEL call: We send a GRANT_MSG, the client replies
655 * with a GRANT_RES call which gets lost, and calls UNLOCK immediately
656 * afterwards. In this case the block will still be there, and hence
657 * must be removed.
658 */
52921e02 659__be32
5ccb0066 660nlmsvc_unlock(struct net *net, struct nlm_file *file, struct nlm_lock *lock)
1da177e4
LT
661{
662 int error;
663
664 dprintk("lockd: nlmsvc_unlock(%s/%ld, pi=%d, %Ld-%Ld)\n",
64bed6cb
AG
665 locks_inode(file->f_file)->i_sb->s_id,
666 locks_inode(file->f_file)->i_ino,
1da177e4
LT
667 lock->fl.fl_pid,
668 (long long)lock->fl.fl_start,
669 (long long)lock->fl.fl_end);
670
671 /* First, cancel any lock that might be there */
5ccb0066 672 nlmsvc_cancel_blocked(net, file, lock);
1da177e4
LT
673
674 lock->fl.fl_type = F_UNLCK;
1a8322b2 675 error = vfs_lock_file(file->f_file, F_SETLK, &lock->fl, NULL);
1da177e4
LT
676
677 return (error < 0)? nlm_lck_denied_nolocks : nlm_granted;
678}
679
680/*
681 * Cancel a previously blocked request.
682 *
683 * A cancel request always overrides any grant that may currently
684 * be in progress.
685 * The calling procedure must check whether the file can be closed.
686 */
52921e02 687__be32
5ccb0066 688nlmsvc_cancel_blocked(struct net *net, struct nlm_file *file, struct nlm_lock *lock)
1da177e4
LT
689{
690 struct nlm_block *block;
64a318ee 691 int status = 0;
1da177e4
LT
692
693 dprintk("lockd: nlmsvc_cancel(%s/%ld, pi=%d, %Ld-%Ld)\n",
64bed6cb
AG
694 locks_inode(file->f_file)->i_sb->s_id,
695 locks_inode(file->f_file)->i_ino,
1da177e4
LT
696 lock->fl.fl_pid,
697 (long long)lock->fl.fl_start,
698 (long long)lock->fl.fl_end);
699
5ccb0066 700 if (locks_in_grace(net))
b2b50289
BF
701 return nlm_lck_denied_grace_period;
702
89e63ef6 703 mutex_lock(&file->f_mutex);
d9f6eb75 704 block = nlmsvc_lookup_block(file, lock);
89e63ef6 705 mutex_unlock(&file->f_mutex);
d9f6eb75 706 if (block != NULL) {
1a8322b2
ME
707 vfs_cancel_lock(block->b_file->f_file,
708 &block->b_call->a_args.lock.fl);
6849c0ca
TM
709 status = nlmsvc_unlink_block(block);
710 nlmsvc_release_block(block);
711 }
64a318ee 712 return status ? nlm_lck_denied : nlm_granted;
1da177e4
LT
713}
714
0e4ac9d9
ME
715/*
716 * This is a callback from the filesystem for VFS file lock requests.
8fb47a4f 717 * It will be used if lm_grant is defined and the filesystem can not
0e4ac9d9 718 * respond to the request immediately.
0e4ac9d9
ME
719 * For SETLK or SETLKW request it will get the local posix lock.
720 * In all cases it will move the block to the head of nlm_blocked q where
721 * nlmsvc_retry_blocked() can send back a reply for SETLKW or revisit the
722 * deferred rpc for GETLK and SETLK.
723 */
724static void
d0449b90 725nlmsvc_update_deferred_block(struct nlm_block *block, int result)
0e4ac9d9
ME
726{
727 block->b_flags |= B_GOT_CALLBACK;
728 if (result == 0)
729 block->b_granted = 1;
730 else
731 block->b_flags |= B_TIMED_OUT;
0e4ac9d9
ME
732}
733
d0449b90 734static int nlmsvc_grant_deferred(struct file_lock *fl, int result)
0e4ac9d9
ME
735{
736 struct nlm_block *block;
737 int rc = -ENOENT;
738
f904be9c 739 spin_lock(&nlm_blocked_lock);
0e4ac9d9
ME
740 list_for_each_entry(block, &nlm_blocked, b_list) {
741 if (nlm_compare_locks(&block->b_call->a_args.lock.fl, fl)) {
742 dprintk("lockd: nlmsvc_notify_blocked block %p flags %d\n",
743 block, block->b_flags);
744 if (block->b_flags & B_QUEUED) {
745 if (block->b_flags & B_TIMED_OUT) {
746 rc = -ENOLCK;
747 break;
748 }
d0449b90 749 nlmsvc_update_deferred_block(block, result);
0e4ac9d9
ME
750 } else if (result == 0)
751 block->b_granted = 1;
752
f904be9c 753 nlmsvc_insert_block_locked(block, 0);
0e4ac9d9
ME
754 svc_wake_up(block->b_daemon);
755 rc = 0;
756 break;
757 }
758 }
f904be9c 759 spin_unlock(&nlm_blocked_lock);
0e4ac9d9
ME
760 if (rc == -ENOENT)
761 printk(KERN_WARNING "lockd: grant for unknown block\n");
762 return rc;
763}
764
1da177e4
LT
765/*
766 * Unblock a blocked lock request. This is a callback invoked from the
767 * VFS layer when a lock on which we blocked is removed.
768 *
769 * This function doesn't grant the blocked lock instantly, but rather moves
770 * the block to the head of nlm_blocked where it can be picked up by lockd.
771 */
772static void
773nlmsvc_notify_blocked(struct file_lock *fl)
774{
68a2d76c 775 struct nlm_block *block;
1da177e4
LT
776
777 dprintk("lockd: VFS unblock notification for block %p\n", fl);
a282a1fa 778 spin_lock(&nlm_blocked_lock);
68a2d76c 779 list_for_each_entry(block, &nlm_blocked, b_list) {
92737230 780 if (nlm_compare_locks(&block->b_call->a_args.lock.fl, fl)) {
a282a1fa
BF
781 nlmsvc_insert_block_locked(block, 0);
782 spin_unlock(&nlm_blocked_lock);
1da177e4
LT
783 svc_wake_up(block->b_daemon);
784 return;
785 }
786 }
a282a1fa 787 spin_unlock(&nlm_blocked_lock);
1da177e4
LT
788 printk(KERN_WARNING "lockd: notification for unknown block!\n");
789}
790
7b021967 791const struct lock_manager_operations nlmsvc_lock_operations = {
8fb47a4f
BF
792 .lm_notify = nlmsvc_notify_blocked,
793 .lm_grant = nlmsvc_grant_deferred,
1da177e4
LT
794};
795
796/*
797 * Try to claim a lock that was previously blocked.
798 *
799 * Note that we use both the RPC_GRANTED_MSG call _and_ an async
800 * RPC thread when notifying the client. This seems like overkill...
801 * Here's why:
802 * - we don't want to use a synchronous RPC thread, otherwise
803 * we might find ourselves hanging on a dead portmapper.
804 * - Some lockd implementations (e.g. HP) don't react to
805 * RPC_GRANTED calls; they seem to insist on RPC_GRANTED_MSG calls.
806 */
807static void
808nlmsvc_grant_blocked(struct nlm_block *block)
809{
810 struct nlm_file *file = block->b_file;
92737230 811 struct nlm_lock *lock = &block->b_call->a_args.lock;
1da177e4 812 int error;
2ec197db 813 loff_t fl_start, fl_end;
1da177e4
LT
814
815 dprintk("lockd: grant blocked lock %p\n", block);
816
0e4ac9d9
ME
817 kref_get(&block->b_count);
818
1da177e4 819 /* Unlink block request from list */
6849c0ca 820 nlmsvc_unlink_block(block);
1da177e4
LT
821
822 /* If b_granted is true this means we've been here before.
823 * Just retry the grant callback, possibly refreshing the RPC
824 * binding */
825 if (block->b_granted) {
826 nlm_rebind_host(block->b_host);
827 goto callback;
828 }
829
830 /* Try the lock operation again */
2ec197db
N
831 /* vfs_lock_file() can mangle fl_start and fl_end, but we need
832 * them unchanged for the GRANT_MSG
833 */
09c7938c 834 lock->fl.fl_flags |= FL_SLEEP;
2ec197db
N
835 fl_start = lock->fl.fl_start;
836 fl_end = lock->fl.fl_end;
1a8322b2 837 error = vfs_lock_file(file->f_file, F_SETLK, &lock->fl, NULL);
09c7938c 838 lock->fl.fl_flags &= ~FL_SLEEP;
2ec197db
N
839 lock->fl.fl_start = fl_start;
840 lock->fl.fl_end = fl_end;
09c7938c 841
5de0e502
AA
842 switch (error) {
843 case 0:
844 break;
bde74e4b 845 case FILE_LOCK_DEFERRED:
1a8322b2 846 dprintk("lockd: lock still blocked error %d\n", error);
1da177e4 847 nlmsvc_insert_block(block, NLM_NEVER);
0e4ac9d9 848 nlmsvc_release_block(block);
d9f6eb75 849 return;
5de0e502 850 default:
1da177e4 851 printk(KERN_WARNING "lockd: unexpected error %d in %s!\n",
8e24eea7 852 -error, __func__);
1da177e4 853 nlmsvc_insert_block(block, 10 * HZ);
0e4ac9d9 854 nlmsvc_release_block(block);
d9f6eb75 855 return;
1da177e4
LT
856 }
857
858callback:
859 /* Lock was granted by VFS. */
860 dprintk("lockd: GRANTing blocked lock.\n");
861 block->b_granted = 1;
1da177e4 862
9706501e
JL
863 /* keep block on the list, but don't reattempt until the RPC
864 * completes or the submission fails
865 */
866 nlmsvc_insert_block(block, NLM_NEVER);
1da177e4 867
9706501e
JL
868 /* Call the client -- use a soft RPC task since nlmsvc_retry_blocked
869 * will queue up a new one if this one times out
870 */
871 error = nlm_async_call(block->b_call, NLMPROC_GRANTED_MSG,
872 &nlmsvc_grant_ops);
873
874 /* RPC submission failed, wait a bit and retry */
875 if (error < 0)
876 nlmsvc_insert_block(block, 10 * HZ);
1da177e4
LT
877}
878
879/*
880 * This is the callback from the RPC layer when the NLM_GRANTED_MSG
881 * RPC call has succeeded or timed out.
882 * Like all RPC callbacks, it is invoked by the rpciod process, so it
883 * better not sleep. Therefore, we put the blocked lock on the nlm_blocked
884 * chain once more in order to have it removed by lockd itself (which can
885 * then sleep on the file semaphore without disrupting e.g. the nfs client).
886 */
963d8fe5 887static void nlmsvc_grant_callback(struct rpc_task *task, void *data)
1da177e4 888{
963d8fe5 889 struct nlm_rqst *call = data;
92737230 890 struct nlm_block *block = call->a_block;
1da177e4 891 unsigned long timeout;
1da177e4
LT
892
893 dprintk("lockd: GRANT_MSG RPC callback\n");
1da177e4 894
f904be9c 895 spin_lock(&nlm_blocked_lock);
c64e80d5
JL
896 /* if the block is not on a list at this point then it has
897 * been invalidated. Don't try to requeue it.
898 *
899 * FIXME: it's possible that the block is removed from the list
900 * after this check but before the nlmsvc_insert_block. In that
901 * case it will be added back. Perhaps we need better locking
902 * for nlm_blocked?
903 */
904 if (list_empty(&block->b_list))
a86dc496 905 goto out;
c64e80d5 906
1da177e4
LT
907 /* Technically, we should down the file semaphore here. Since we
908 * move the block towards the head of the queue only, no harm
909 * can be done, though. */
910 if (task->tk_status < 0) {
911 /* RPC error: Re-insert for retransmission */
912 timeout = 10 * HZ;
1da177e4
LT
913 } else {
914 /* Call was successful, now wait for client callback */
915 timeout = 60 * HZ;
916 }
f904be9c 917 nlmsvc_insert_block_locked(block, timeout);
1da177e4 918 svc_wake_up(block->b_daemon);
a86dc496 919out:
f904be9c 920 spin_unlock(&nlm_blocked_lock);
5e1abf8c
TM
921}
922
f904be9c
BS
923/*
924 * FIXME: nlmsvc_release_block() grabs a mutex. This is not allowed for an
925 * .rpc_release rpc_call_op
926 */
ec535ce1 927static void nlmsvc_grant_release(void *data)
5e1abf8c 928{
6041b791 929 struct nlm_rqst *call = data;
6041b791 930 nlmsvc_release_block(call->a_block);
1da177e4
LT
931}
932
963d8fe5
TM
933static const struct rpc_call_ops nlmsvc_grant_ops = {
934 .rpc_call_done = nlmsvc_grant_callback,
5e1abf8c 935 .rpc_release = nlmsvc_grant_release,
963d8fe5
TM
936};
937
1da177e4
LT
938/*
939 * We received a GRANT_RES callback. Try to find the corresponding
940 * block.
941 */
942void
e8c5c045 943nlmsvc_grant_reply(struct nlm_cookie *cookie, __be32 status)
1da177e4
LT
944{
945 struct nlm_block *block;
1da177e4 946
39be4502
OK
947 dprintk("grant_reply: looking for cookie %x, s=%d \n",
948 *(unsigned int *)(cookie->data), status);
949 if (!(block = nlmsvc_find_block(cookie)))
1da177e4 950 return;
1da177e4 951
e56efe93
CIK
952 if (status == nlm_lck_denied_grace_period) {
953 /* Try again in a couple of seconds */
954 nlmsvc_insert_block(block, 10 * HZ);
955 } else {
956 /*
957 * Lock is now held by client, or has been rejected.
958 * In both cases, the block should be removed.
959 */
960 nlmsvc_unlink_block(block);
1da177e4 961 }
6849c0ca 962 nlmsvc_release_block(block);
1da177e4
LT
963}
964
0e4ac9d9
ME
965/* Helper function to handle retry of a deferred block.
966 * If it is a blocking lock, call grant_blocked.
967 * For a non-blocking lock or test lock, revisit the request.
968 */
969static void
970retry_deferred_block(struct nlm_block *block)
971{
972 if (!(block->b_flags & B_GOT_CALLBACK))
973 block->b_flags |= B_TIMED_OUT;
974 nlmsvc_insert_block(block, NLM_TIMEOUT);
975 dprintk("revisit block %p flags %d\n", block, block->b_flags);
976 if (block->b_deferred_req) {
977 block->b_deferred_req->revisit(block->b_deferred_req, 0);
978 block->b_deferred_req = NULL;
979 }
980}
981
1da177e4
LT
982/*
983 * Retry all blocked locks that have been notified. This is where lockd
984 * picks up locks that can be granted, or grant notifications that must
985 * be retransmitted.
986 */
987unsigned long
988nlmsvc_retry_blocked(void)
989{
68a2d76c
OK
990 unsigned long timeout = MAX_SCHEDULE_TIMEOUT;
991 struct nlm_block *block;
992
1c327d96 993 spin_lock(&nlm_blocked_lock);
d751a7cd 994 while (!list_empty(&nlm_blocked) && !kthread_should_stop()) {
68a2d76c 995 block = list_entry(nlm_blocked.next, struct nlm_block, b_list);
1da177e4 996
1da177e4
LT
997 if (block->b_when == NLM_NEVER)
998 break;
6d7bbbba 999 if (time_after(block->b_when, jiffies)) {
68a2d76c 1000 timeout = block->b_when - jiffies;
1da177e4 1001 break;
68a2d76c 1002 }
1c327d96 1003 spin_unlock(&nlm_blocked_lock);
68a2d76c 1004
f3d43c76
BF
1005 dprintk("nlmsvc_retry_blocked(%p, when=%ld)\n",
1006 block, block->b_when);
0e4ac9d9
ME
1007 if (block->b_flags & B_QUEUED) {
1008 dprintk("nlmsvc_retry_blocked delete block (%p, granted=%d, flags=%d)\n",
1009 block, block->b_granted, block->b_flags);
1010 retry_deferred_block(block);
1011 } else
1012 nlmsvc_grant_blocked(block);
1c327d96 1013 spin_lock(&nlm_blocked_lock);
1da177e4 1014 }
1c327d96 1015 spin_unlock(&nlm_blocked_lock);
1da177e4 1016
68a2d76c 1017 return timeout;
1da177e4 1018}