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Commit | Line | Data |
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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 | ||
23 | #include <linux/config.h> | |
24 | #include <linux/types.h> | |
25 | #include <linux/errno.h> | |
26 | #include <linux/kernel.h> | |
27 | #include <linux/sched.h> | |
28 | #include <linux/smp_lock.h> | |
29 | #include <linux/sunrpc/clnt.h> | |
30 | #include <linux/sunrpc/svc.h> | |
31 | #include <linux/lockd/nlm.h> | |
32 | #include <linux/lockd/lockd.h> | |
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 | ||
42 | static void nlmsvc_insert_block(struct nlm_block *block, unsigned long); | |
43 | static int nlmsvc_remove_block(struct nlm_block *block); | |
44 | static void nlmsvc_grant_callback(struct rpc_task *task); | |
45 | ||
46 | /* | |
47 | * The list of blocked locks to retry | |
48 | */ | |
49 | static struct nlm_block * nlm_blocked; | |
50 | ||
51 | /* | |
52 | * Insert a blocked lock into the global list | |
53 | */ | |
54 | static void | |
55 | nlmsvc_insert_block(struct nlm_block *block, unsigned long when) | |
56 | { | |
57 | struct nlm_block **bp, *b; | |
58 | ||
59 | dprintk("lockd: nlmsvc_insert_block(%p, %ld)\n", block, when); | |
60 | if (block->b_queued) | |
61 | nlmsvc_remove_block(block); | |
62 | bp = &nlm_blocked; | |
63 | if (when != NLM_NEVER) { | |
64 | if ((when += jiffies) == NLM_NEVER) | |
65 | when ++; | |
66 | while ((b = *bp) && time_before_eq(b->b_when,when) && b->b_when != NLM_NEVER) | |
67 | bp = &b->b_next; | |
68 | } else | |
69 | while ((b = *bp) != 0) | |
70 | bp = &b->b_next; | |
71 | ||
72 | block->b_queued = 1; | |
73 | block->b_when = when; | |
74 | block->b_next = b; | |
75 | *bp = block; | |
76 | } | |
77 | ||
78 | /* | |
79 | * Remove a block from the global list | |
80 | */ | |
81 | static int | |
82 | nlmsvc_remove_block(struct nlm_block *block) | |
83 | { | |
84 | struct nlm_block **bp, *b; | |
85 | ||
86 | if (!block->b_queued) | |
87 | return 1; | |
88 | for (bp = &nlm_blocked; (b = *bp) != 0; bp = &b->b_next) { | |
89 | if (b == block) { | |
90 | *bp = block->b_next; | |
91 | block->b_queued = 0; | |
92 | return 1; | |
93 | } | |
94 | } | |
95 | ||
96 | return 0; | |
97 | } | |
98 | ||
99 | /* | |
100 | * Find a block for a given lock and optionally remove it from | |
101 | * the list. | |
102 | */ | |
103 | static struct nlm_block * | |
104 | nlmsvc_lookup_block(struct nlm_file *file, struct nlm_lock *lock, int remove) | |
105 | { | |
106 | struct nlm_block **head, *block; | |
107 | struct file_lock *fl; | |
108 | ||
109 | dprintk("lockd: nlmsvc_lookup_block f=%p pd=%d %Ld-%Ld ty=%d\n", | |
110 | file, lock->fl.fl_pid, | |
111 | (long long)lock->fl.fl_start, | |
112 | (long long)lock->fl.fl_end, lock->fl.fl_type); | |
113 | for (head = &nlm_blocked; (block = *head) != 0; head = &block->b_next) { | |
114 | fl = &block->b_call.a_args.lock.fl; | |
115 | dprintk("lockd: check f=%p pd=%d %Ld-%Ld ty=%d cookie=%s\n", | |
116 | block->b_file, fl->fl_pid, | |
117 | (long long)fl->fl_start, | |
118 | (long long)fl->fl_end, fl->fl_type, | |
119 | nlmdbg_cookie2a(&block->b_call.a_args.cookie)); | |
120 | if (block->b_file == file && nlm_compare_locks(fl, &lock->fl)) { | |
121 | if (remove) { | |
122 | *head = block->b_next; | |
123 | block->b_queued = 0; | |
124 | } | |
125 | return block; | |
126 | } | |
127 | } | |
128 | ||
129 | return NULL; | |
130 | } | |
131 | ||
132 | static inline int nlm_cookie_match(struct nlm_cookie *a, struct nlm_cookie *b) | |
133 | { | |
134 | if(a->len != b->len) | |
135 | return 0; | |
136 | if(memcmp(a->data,b->data,a->len)) | |
137 | return 0; | |
138 | return 1; | |
139 | } | |
140 | ||
141 | /* | |
142 | * Find a block with a given NLM cookie. | |
143 | */ | |
144 | static inline struct nlm_block * | |
145 | nlmsvc_find_block(struct nlm_cookie *cookie, struct sockaddr_in *sin) | |
146 | { | |
147 | struct nlm_block *block; | |
148 | ||
149 | for (block = nlm_blocked; block; block = block->b_next) { | |
150 | dprintk("cookie: head of blocked queue %p, block %p\n", | |
151 | nlm_blocked, block); | |
152 | if (nlm_cookie_match(&block->b_call.a_args.cookie,cookie) | |
153 | && nlm_cmp_addr(sin, &block->b_host->h_addr)) | |
154 | break; | |
155 | } | |
156 | ||
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. | |
169 | */ | |
170 | static inline struct nlm_block * | |
171 | nlmsvc_create_block(struct svc_rqst *rqstp, struct nlm_file *file, | |
172 | struct nlm_lock *lock, struct nlm_cookie *cookie) | |
173 | { | |
174 | struct nlm_block *block; | |
175 | struct nlm_host *host; | |
176 | struct nlm_rqst *call; | |
177 | ||
178 | /* Create host handle for callback */ | |
179 | host = nlmclnt_lookup_host(&rqstp->rq_addr, | |
180 | rqstp->rq_prot, rqstp->rq_vers); | |
181 | if (host == NULL) | |
182 | return NULL; | |
183 | ||
184 | /* Allocate memory for block, and initialize arguments */ | |
185 | if (!(block = (struct nlm_block *) kmalloc(sizeof(*block), GFP_KERNEL))) | |
186 | goto failed; | |
187 | memset(block, 0, sizeof(*block)); | |
188 | locks_init_lock(&block->b_call.a_args.lock.fl); | |
189 | locks_init_lock(&block->b_call.a_res.lock.fl); | |
190 | ||
191 | if (!nlmclnt_setgrantargs(&block->b_call, lock)) | |
192 | goto failed_free; | |
193 | ||
194 | /* Set notifier function for VFS, and init args */ | |
195 | block->b_call.a_args.lock.fl.fl_lmops = &nlmsvc_lock_operations; | |
196 | block->b_call.a_args.cookie = *cookie; /* see above */ | |
197 | ||
198 | dprintk("lockd: created block %p...\n", block); | |
199 | ||
200 | /* Create and initialize the block */ | |
201 | block->b_daemon = rqstp->rq_server; | |
202 | block->b_host = host; | |
203 | block->b_file = file; | |
204 | ||
205 | /* Add to file's list of blocks */ | |
206 | block->b_fnext = file->f_blocks; | |
207 | file->f_blocks = block; | |
208 | ||
209 | /* Set up RPC arguments for callback */ | |
210 | call = &block->b_call; | |
211 | call->a_host = host; | |
212 | call->a_flags = RPC_TASK_ASYNC; | |
213 | ||
214 | return block; | |
215 | ||
216 | failed_free: | |
217 | kfree(block); | |
218 | failed: | |
219 | nlm_release_host(host); | |
220 | return NULL; | |
221 | } | |
222 | ||
223 | /* | |
224 | * Delete a block. If the lock was cancelled or the grant callback | |
225 | * failed, unlock is set to 1. | |
226 | * It is the caller's responsibility to check whether the file | |
227 | * can be closed hereafter. | |
228 | */ | |
229 | static void | |
230 | nlmsvc_delete_block(struct nlm_block *block, int unlock) | |
231 | { | |
232 | struct file_lock *fl = &block->b_call.a_args.lock.fl; | |
233 | struct nlm_file *file = block->b_file; | |
234 | struct nlm_block **bp; | |
235 | ||
236 | dprintk("lockd: deleting block %p...\n", block); | |
237 | ||
238 | /* Remove block from list */ | |
239 | nlmsvc_remove_block(block); | |
240 | if (fl->fl_next) | |
241 | posix_unblock_lock(file->f_file, fl); | |
242 | if (unlock) { | |
243 | fl->fl_type = F_UNLCK; | |
244 | posix_lock_file(file->f_file, fl); | |
245 | block->b_granted = 0; | |
246 | } | |
247 | ||
248 | /* If the block is in the middle of a GRANT callback, | |
249 | * don't kill it yet. */ | |
250 | if (block->b_incall) { | |
251 | nlmsvc_insert_block(block, NLM_NEVER); | |
252 | block->b_done = 1; | |
253 | return; | |
254 | } | |
255 | ||
256 | /* Remove block from file's list of blocks */ | |
257 | for (bp = &file->f_blocks; *bp; bp = &(*bp)->b_fnext) { | |
258 | if (*bp == block) { | |
259 | *bp = block->b_fnext; | |
260 | break; | |
261 | } | |
262 | } | |
263 | ||
264 | if (block->b_host) | |
265 | nlm_release_host(block->b_host); | |
266 | nlmclnt_freegrantargs(&block->b_call); | |
267 | kfree(block); | |
268 | } | |
269 | ||
270 | /* | |
271 | * Loop over all blocks and perform the action specified. | |
272 | * (NLM_ACT_CHECK handled by nlmsvc_inspect_file). | |
273 | */ | |
274 | int | |
275 | nlmsvc_traverse_blocks(struct nlm_host *host, struct nlm_file *file, int action) | |
276 | { | |
277 | struct nlm_block *block, *next; | |
278 | ||
279 | down(&file->f_sema); | |
280 | for (block = file->f_blocks; block; block = next) { | |
281 | next = block->b_fnext; | |
282 | if (action == NLM_ACT_MARK) | |
283 | block->b_host->h_inuse = 1; | |
284 | else if (action == NLM_ACT_UNLOCK) { | |
285 | if (host == NULL || host == block->b_host) | |
286 | nlmsvc_delete_block(block, 1); | |
287 | } | |
288 | } | |
289 | up(&file->f_sema); | |
290 | return 0; | |
291 | } | |
292 | ||
293 | /* | |
294 | * Attempt to establish a lock, and if it can't be granted, block it | |
295 | * if required. | |
296 | */ | |
297 | u32 | |
298 | nlmsvc_lock(struct svc_rqst *rqstp, struct nlm_file *file, | |
299 | struct nlm_lock *lock, int wait, struct nlm_cookie *cookie) | |
300 | { | |
301 | struct file_lock *conflock; | |
302 | struct nlm_block *block; | |
303 | int error; | |
304 | ||
305 | dprintk("lockd: nlmsvc_lock(%s/%ld, ty=%d, pi=%d, %Ld-%Ld, bl=%d)\n", | |
306 | file->f_file->f_dentry->d_inode->i_sb->s_id, | |
307 | file->f_file->f_dentry->d_inode->i_ino, | |
308 | lock->fl.fl_type, lock->fl.fl_pid, | |
309 | (long long)lock->fl.fl_start, | |
310 | (long long)lock->fl.fl_end, | |
311 | wait); | |
312 | ||
313 | ||
314 | /* Get existing block (in case client is busy-waiting) */ | |
315 | block = nlmsvc_lookup_block(file, lock, 0); | |
316 | ||
317 | lock->fl.fl_flags |= FL_LOCKD; | |
318 | ||
319 | again: | |
320 | /* Lock file against concurrent access */ | |
321 | down(&file->f_sema); | |
322 | ||
323 | if (!(conflock = posix_test_lock(file->f_file, &lock->fl))) { | |
324 | error = posix_lock_file(file->f_file, &lock->fl); | |
325 | ||
326 | if (block) | |
327 | nlmsvc_delete_block(block, 0); | |
328 | up(&file->f_sema); | |
329 | ||
330 | dprintk("lockd: posix_lock_file returned %d\n", -error); | |
331 | switch(-error) { | |
332 | case 0: | |
333 | return nlm_granted; | |
334 | case EDEADLK: | |
335 | return nlm_deadlock; | |
336 | case EAGAIN: | |
337 | return nlm_lck_denied; | |
338 | default: /* includes ENOLCK */ | |
339 | return nlm_lck_denied_nolocks; | |
340 | } | |
341 | } | |
342 | ||
343 | if (!wait) { | |
344 | up(&file->f_sema); | |
345 | return nlm_lck_denied; | |
346 | } | |
347 | ||
348 | if (posix_locks_deadlock(&lock->fl, conflock)) { | |
349 | up(&file->f_sema); | |
350 | return nlm_deadlock; | |
351 | } | |
352 | ||
353 | /* If we don't have a block, create and initialize it. Then | |
354 | * retry because we may have slept in kmalloc. */ | |
355 | /* We have to release f_sema as nlmsvc_create_block may try to | |
356 | * to claim it while doing host garbage collection */ | |
357 | if (block == NULL) { | |
358 | up(&file->f_sema); | |
359 | dprintk("lockd: blocking on this lock (allocating).\n"); | |
360 | if (!(block = nlmsvc_create_block(rqstp, file, lock, cookie))) | |
361 | return nlm_lck_denied_nolocks; | |
362 | goto again; | |
363 | } | |
364 | ||
365 | /* Append to list of blocked */ | |
366 | nlmsvc_insert_block(block, NLM_NEVER); | |
367 | ||
368 | if (list_empty(&block->b_call.a_args.lock.fl.fl_block)) { | |
369 | /* Now add block to block list of the conflicting lock | |
370 | if we haven't done so. */ | |
371 | dprintk("lockd: blocking on this lock.\n"); | |
372 | posix_block_lock(conflock, &block->b_call.a_args.lock.fl); | |
373 | } | |
374 | ||
375 | up(&file->f_sema); | |
376 | return nlm_lck_blocked; | |
377 | } | |
378 | ||
379 | /* | |
380 | * Test for presence of a conflicting lock. | |
381 | */ | |
382 | u32 | |
383 | nlmsvc_testlock(struct nlm_file *file, struct nlm_lock *lock, | |
384 | struct nlm_lock *conflock) | |
385 | { | |
386 | struct file_lock *fl; | |
387 | ||
388 | dprintk("lockd: nlmsvc_testlock(%s/%ld, ty=%d, %Ld-%Ld)\n", | |
389 | file->f_file->f_dentry->d_inode->i_sb->s_id, | |
390 | file->f_file->f_dentry->d_inode->i_ino, | |
391 | lock->fl.fl_type, | |
392 | (long long)lock->fl.fl_start, | |
393 | (long long)lock->fl.fl_end); | |
394 | ||
395 | if ((fl = posix_test_lock(file->f_file, &lock->fl)) != NULL) { | |
396 | dprintk("lockd: conflicting lock(ty=%d, %Ld-%Ld)\n", | |
397 | fl->fl_type, (long long)fl->fl_start, | |
398 | (long long)fl->fl_end); | |
399 | conflock->caller = "somehost"; /* FIXME */ | |
400 | conflock->oh.len = 0; /* don't return OH info */ | |
401 | conflock->fl = *fl; | |
402 | return nlm_lck_denied; | |
403 | } | |
404 | ||
405 | return nlm_granted; | |
406 | } | |
407 | ||
408 | /* | |
409 | * Remove a lock. | |
410 | * This implies a CANCEL call: We send a GRANT_MSG, the client replies | |
411 | * with a GRANT_RES call which gets lost, and calls UNLOCK immediately | |
412 | * afterwards. In this case the block will still be there, and hence | |
413 | * must be removed. | |
414 | */ | |
415 | u32 | |
416 | nlmsvc_unlock(struct nlm_file *file, struct nlm_lock *lock) | |
417 | { | |
418 | int error; | |
419 | ||
420 | dprintk("lockd: nlmsvc_unlock(%s/%ld, pi=%d, %Ld-%Ld)\n", | |
421 | file->f_file->f_dentry->d_inode->i_sb->s_id, | |
422 | file->f_file->f_dentry->d_inode->i_ino, | |
423 | lock->fl.fl_pid, | |
424 | (long long)lock->fl.fl_start, | |
425 | (long long)lock->fl.fl_end); | |
426 | ||
427 | /* First, cancel any lock that might be there */ | |
428 | nlmsvc_cancel_blocked(file, lock); | |
429 | ||
430 | lock->fl.fl_type = F_UNLCK; | |
431 | error = posix_lock_file(file->f_file, &lock->fl); | |
432 | ||
433 | return (error < 0)? nlm_lck_denied_nolocks : nlm_granted; | |
434 | } | |
435 | ||
436 | /* | |
437 | * Cancel a previously blocked request. | |
438 | * | |
439 | * A cancel request always overrides any grant that may currently | |
440 | * be in progress. | |
441 | * The calling procedure must check whether the file can be closed. | |
442 | */ | |
443 | u32 | |
444 | nlmsvc_cancel_blocked(struct nlm_file *file, struct nlm_lock *lock) | |
445 | { | |
446 | struct nlm_block *block; | |
447 | ||
448 | dprintk("lockd: nlmsvc_cancel(%s/%ld, pi=%d, %Ld-%Ld)\n", | |
449 | file->f_file->f_dentry->d_inode->i_sb->s_id, | |
450 | file->f_file->f_dentry->d_inode->i_ino, | |
451 | lock->fl.fl_pid, | |
452 | (long long)lock->fl.fl_start, | |
453 | (long long)lock->fl.fl_end); | |
454 | ||
455 | down(&file->f_sema); | |
456 | if ((block = nlmsvc_lookup_block(file, lock, 1)) != NULL) | |
457 | nlmsvc_delete_block(block, 1); | |
458 | up(&file->f_sema); | |
459 | return nlm_granted; | |
460 | } | |
461 | ||
462 | /* | |
463 | * Unblock a blocked lock request. This is a callback invoked from the | |
464 | * VFS layer when a lock on which we blocked is removed. | |
465 | * | |
466 | * This function doesn't grant the blocked lock instantly, but rather moves | |
467 | * the block to the head of nlm_blocked where it can be picked up by lockd. | |
468 | */ | |
469 | static void | |
470 | nlmsvc_notify_blocked(struct file_lock *fl) | |
471 | { | |
472 | struct nlm_block **bp, *block; | |
473 | ||
474 | dprintk("lockd: VFS unblock notification for block %p\n", fl); | |
475 | for (bp = &nlm_blocked; (block = *bp) != 0; bp = &block->b_next) { | |
476 | if (nlm_compare_locks(&block->b_call.a_args.lock.fl, fl)) { | |
477 | nlmsvc_insert_block(block, 0); | |
478 | svc_wake_up(block->b_daemon); | |
479 | return; | |
480 | } | |
481 | } | |
482 | ||
483 | printk(KERN_WARNING "lockd: notification for unknown block!\n"); | |
484 | } | |
485 | ||
486 | static int nlmsvc_same_owner(struct file_lock *fl1, struct file_lock *fl2) | |
487 | { | |
488 | return fl1->fl_owner == fl2->fl_owner && fl1->fl_pid == fl2->fl_pid; | |
489 | } | |
490 | ||
491 | struct lock_manager_operations nlmsvc_lock_operations = { | |
492 | .fl_compare_owner = nlmsvc_same_owner, | |
493 | .fl_notify = nlmsvc_notify_blocked, | |
494 | }; | |
495 | ||
496 | /* | |
497 | * Try to claim a lock that was previously blocked. | |
498 | * | |
499 | * Note that we use both the RPC_GRANTED_MSG call _and_ an async | |
500 | * RPC thread when notifying the client. This seems like overkill... | |
501 | * Here's why: | |
502 | * - we don't want to use a synchronous RPC thread, otherwise | |
503 | * we might find ourselves hanging on a dead portmapper. | |
504 | * - Some lockd implementations (e.g. HP) don't react to | |
505 | * RPC_GRANTED calls; they seem to insist on RPC_GRANTED_MSG calls. | |
506 | */ | |
507 | static void | |
508 | nlmsvc_grant_blocked(struct nlm_block *block) | |
509 | { | |
510 | struct nlm_file *file = block->b_file; | |
511 | struct nlm_lock *lock = &block->b_call.a_args.lock; | |
512 | struct file_lock *conflock; | |
513 | int error; | |
514 | ||
515 | dprintk("lockd: grant blocked lock %p\n", block); | |
516 | ||
517 | /* First thing is lock the file */ | |
518 | down(&file->f_sema); | |
519 | ||
520 | /* Unlink block request from list */ | |
521 | nlmsvc_remove_block(block); | |
522 | ||
523 | /* If b_granted is true this means we've been here before. | |
524 | * Just retry the grant callback, possibly refreshing the RPC | |
525 | * binding */ | |
526 | if (block->b_granted) { | |
527 | nlm_rebind_host(block->b_host); | |
528 | goto callback; | |
529 | } | |
530 | ||
531 | /* Try the lock operation again */ | |
532 | if ((conflock = posix_test_lock(file->f_file, &lock->fl)) != NULL) { | |
533 | /* Bummer, we blocked again */ | |
534 | dprintk("lockd: lock still blocked\n"); | |
535 | nlmsvc_insert_block(block, NLM_NEVER); | |
536 | posix_block_lock(conflock, &lock->fl); | |
537 | up(&file->f_sema); | |
538 | return; | |
539 | } | |
540 | ||
541 | /* Alright, no conflicting lock. Now lock it for real. If the | |
542 | * following yields an error, this is most probably due to low | |
543 | * memory. Retry the lock in a few seconds. | |
544 | */ | |
545 | if ((error = posix_lock_file(file->f_file, &lock->fl)) < 0) { | |
546 | printk(KERN_WARNING "lockd: unexpected error %d in %s!\n", | |
547 | -error, __FUNCTION__); | |
548 | nlmsvc_insert_block(block, 10 * HZ); | |
549 | up(&file->f_sema); | |
550 | return; | |
551 | } | |
552 | ||
553 | callback: | |
554 | /* Lock was granted by VFS. */ | |
555 | dprintk("lockd: GRANTing blocked lock.\n"); | |
556 | block->b_granted = 1; | |
557 | block->b_incall = 1; | |
558 | ||
559 | /* Schedule next grant callback in 30 seconds */ | |
560 | nlmsvc_insert_block(block, 30 * HZ); | |
561 | ||
562 | /* Call the client */ | |
563 | nlm_get_host(block->b_call.a_host); | |
564 | if (nlmsvc_async_call(&block->b_call, NLMPROC_GRANTED_MSG, | |
565 | nlmsvc_grant_callback) < 0) | |
566 | nlm_release_host(block->b_call.a_host); | |
567 | up(&file->f_sema); | |
568 | } | |
569 | ||
570 | /* | |
571 | * This is the callback from the RPC layer when the NLM_GRANTED_MSG | |
572 | * RPC call has succeeded or timed out. | |
573 | * Like all RPC callbacks, it is invoked by the rpciod process, so it | |
574 | * better not sleep. Therefore, we put the blocked lock on the nlm_blocked | |
575 | * chain once more in order to have it removed by lockd itself (which can | |
576 | * then sleep on the file semaphore without disrupting e.g. the nfs client). | |
577 | */ | |
578 | static void | |
579 | nlmsvc_grant_callback(struct rpc_task *task) | |
580 | { | |
581 | struct nlm_rqst *call = (struct nlm_rqst *) task->tk_calldata; | |
582 | struct nlm_block *block; | |
583 | unsigned long timeout; | |
584 | struct sockaddr_in *peer_addr = RPC_PEERADDR(task->tk_client); | |
585 | ||
586 | dprintk("lockd: GRANT_MSG RPC callback\n"); | |
587 | dprintk("callback: looking for cookie %s, host (%u.%u.%u.%u)\n", | |
588 | nlmdbg_cookie2a(&call->a_args.cookie), | |
589 | NIPQUAD(peer_addr->sin_addr.s_addr)); | |
590 | if (!(block = nlmsvc_find_block(&call->a_args.cookie, peer_addr))) { | |
591 | dprintk("lockd: no block for cookie %s, host (%u.%u.%u.%u)\n", | |
592 | nlmdbg_cookie2a(&call->a_args.cookie), | |
593 | NIPQUAD(peer_addr->sin_addr.s_addr)); | |
594 | return; | |
595 | } | |
596 | ||
597 | /* Technically, we should down the file semaphore here. Since we | |
598 | * move the block towards the head of the queue only, no harm | |
599 | * can be done, though. */ | |
600 | if (task->tk_status < 0) { | |
601 | /* RPC error: Re-insert for retransmission */ | |
602 | timeout = 10 * HZ; | |
603 | } else if (block->b_done) { | |
604 | /* Block already removed, kill it for real */ | |
605 | timeout = 0; | |
606 | } else { | |
607 | /* Call was successful, now wait for client callback */ | |
608 | timeout = 60 * HZ; | |
609 | } | |
610 | nlmsvc_insert_block(block, timeout); | |
611 | svc_wake_up(block->b_daemon); | |
612 | block->b_incall = 0; | |
613 | ||
614 | nlm_release_host(call->a_host); | |
615 | } | |
616 | ||
617 | /* | |
618 | * We received a GRANT_RES callback. Try to find the corresponding | |
619 | * block. | |
620 | */ | |
621 | void | |
622 | nlmsvc_grant_reply(struct svc_rqst *rqstp, struct nlm_cookie *cookie, u32 status) | |
623 | { | |
624 | struct nlm_block *block; | |
625 | struct nlm_file *file; | |
626 | ||
627 | dprintk("grant_reply: looking for cookie %x, host (%08x), s=%d \n", | |
628 | *(unsigned int *)(cookie->data), | |
629 | ntohl(rqstp->rq_addr.sin_addr.s_addr), status); | |
630 | if (!(block = nlmsvc_find_block(cookie, &rqstp->rq_addr))) | |
631 | return; | |
632 | file = block->b_file; | |
633 | ||
634 | file->f_count++; | |
635 | down(&file->f_sema); | |
636 | if ((block = nlmsvc_find_block(cookie,&rqstp->rq_addr)) != NULL) { | |
637 | if (status == NLM_LCK_DENIED_GRACE_PERIOD) { | |
638 | /* Try again in a couple of seconds */ | |
639 | nlmsvc_insert_block(block, 10 * HZ); | |
640 | block = NULL; | |
641 | } else { | |
642 | /* Lock is now held by client, or has been rejected. | |
643 | * In both cases, the block should be removed. */ | |
644 | up(&file->f_sema); | |
645 | if (status == NLM_LCK_GRANTED) | |
646 | nlmsvc_delete_block(block, 0); | |
647 | else | |
648 | nlmsvc_delete_block(block, 1); | |
649 | } | |
650 | } | |
651 | if (!block) | |
652 | up(&file->f_sema); | |
653 | nlm_release_file(file); | |
654 | } | |
655 | ||
656 | /* | |
657 | * Retry all blocked locks that have been notified. This is where lockd | |
658 | * picks up locks that can be granted, or grant notifications that must | |
659 | * be retransmitted. | |
660 | */ | |
661 | unsigned long | |
662 | nlmsvc_retry_blocked(void) | |
663 | { | |
664 | struct nlm_block *block; | |
665 | ||
666 | dprintk("nlmsvc_retry_blocked(%p, when=%ld)\n", | |
667 | nlm_blocked, | |
668 | nlm_blocked? nlm_blocked->b_when : 0); | |
669 | while ((block = nlm_blocked) != 0) { | |
670 | if (block->b_when == NLM_NEVER) | |
671 | break; | |
672 | if (time_after(block->b_when,jiffies)) | |
673 | break; | |
674 | dprintk("nlmsvc_retry_blocked(%p, when=%ld, done=%d)\n", | |
675 | block, block->b_when, block->b_done); | |
676 | if (block->b_done) | |
677 | nlmsvc_delete_block(block, 0); | |
678 | else | |
679 | nlmsvc_grant_blocked(block); | |
680 | } | |
681 | ||
682 | if ((block = nlm_blocked) && block->b_when != NLM_NEVER) | |
683 | return (block->b_when - jiffies); | |
684 | ||
685 | return MAX_SCHEDULE_TIMEOUT; | |
686 | } |