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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); | |
963d8fe5 TM |
44 | |
45 | static const struct rpc_call_ops nlmsvc_grant_ops; | |
1da177e4 LT |
46 | |
47 | /* | |
48 | * The list of blocked locks to retry | |
49 | */ | |
50 | static struct nlm_block * nlm_blocked; | |
51 | ||
52 | /* | |
53 | * Insert a blocked lock into the global list | |
54 | */ | |
55 | static void | |
56 | nlmsvc_insert_block(struct nlm_block *block, unsigned long when) | |
57 | { | |
58 | struct nlm_block **bp, *b; | |
59 | ||
60 | dprintk("lockd: nlmsvc_insert_block(%p, %ld)\n", block, when); | |
61 | if (block->b_queued) | |
62 | nlmsvc_remove_block(block); | |
63 | bp = &nlm_blocked; | |
64 | if (when != NLM_NEVER) { | |
65 | if ((when += jiffies) == NLM_NEVER) | |
66 | when ++; | |
67 | while ((b = *bp) && time_before_eq(b->b_when,when) && b->b_when != NLM_NEVER) | |
68 | bp = &b->b_next; | |
69 | } else | |
70 | while ((b = *bp) != 0) | |
71 | bp = &b->b_next; | |
72 | ||
73 | block->b_queued = 1; | |
74 | block->b_when = when; | |
75 | block->b_next = b; | |
76 | *bp = block; | |
77 | } | |
78 | ||
79 | /* | |
80 | * Remove a block from the global list | |
81 | */ | |
82 | static int | |
83 | nlmsvc_remove_block(struct nlm_block *block) | |
84 | { | |
85 | struct nlm_block **bp, *b; | |
86 | ||
87 | if (!block->b_queued) | |
88 | return 1; | |
89 | for (bp = &nlm_blocked; (b = *bp) != 0; bp = &b->b_next) { | |
90 | if (b == block) { | |
91 | *bp = block->b_next; | |
92 | block->b_queued = 0; | |
93 | return 1; | |
94 | } | |
95 | } | |
96 | ||
97 | return 0; | |
98 | } | |
99 | ||
100 | /* | |
101 | * Find a block for a given lock and optionally remove it from | |
102 | * the list. | |
103 | */ | |
104 | static struct nlm_block * | |
105 | nlmsvc_lookup_block(struct nlm_file *file, struct nlm_lock *lock, int remove) | |
106 | { | |
107 | struct nlm_block **head, *block; | |
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); | |
114 | for (head = &nlm_blocked; (block = *head) != 0; head = &block->b_next) { | |
115 | fl = &block->b_call.a_args.lock.fl; | |
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, | |
120 | nlmdbg_cookie2a(&block->b_call.a_args.cookie)); | |
121 | if (block->b_file == file && nlm_compare_locks(fl, &lock->fl)) { | |
122 | if (remove) { | |
123 | *head = block->b_next; | |
124 | block->b_queued = 0; | |
125 | } | |
126 | return block; | |
127 | } | |
128 | } | |
129 | ||
130 | return NULL; | |
131 | } | |
132 | ||
133 | static inline int nlm_cookie_match(struct nlm_cookie *a, struct nlm_cookie *b) | |
134 | { | |
135 | if(a->len != b->len) | |
136 | return 0; | |
137 | if(memcmp(a->data,b->data,a->len)) | |
138 | return 0; | |
139 | return 1; | |
140 | } | |
141 | ||
142 | /* | |
143 | * Find a block with a given NLM cookie. | |
144 | */ | |
145 | static inline struct nlm_block * | |
146 | nlmsvc_find_block(struct nlm_cookie *cookie, struct sockaddr_in *sin) | |
147 | { | |
148 | struct nlm_block *block; | |
149 | ||
150 | for (block = nlm_blocked; block; block = block->b_next) { | |
151 | dprintk("cookie: head of blocked queue %p, block %p\n", | |
152 | nlm_blocked, block); | |
153 | if (nlm_cookie_match(&block->b_call.a_args.cookie,cookie) | |
154 | && nlm_cmp_addr(sin, &block->b_host->h_addr)) | |
155 | break; | |
156 | } | |
157 | ||
158 | return block; | |
159 | } | |
160 | ||
161 | /* | |
162 | * Create a block and initialize it. | |
163 | * | |
164 | * Note: we explicitly set the cookie of the grant reply to that of | |
165 | * the blocked lock request. The spec explicitly mentions that the client | |
166 | * should _not_ rely on the callback containing the same cookie as the | |
167 | * request, but (as I found out later) that's because some implementations | |
168 | * do just this. Never mind the standards comittees, they support our | |
169 | * logging industries. | |
170 | */ | |
171 | static inline struct nlm_block * | |
172 | nlmsvc_create_block(struct svc_rqst *rqstp, struct nlm_file *file, | |
173 | struct nlm_lock *lock, struct nlm_cookie *cookie) | |
174 | { | |
175 | struct nlm_block *block; | |
176 | struct nlm_host *host; | |
177 | struct nlm_rqst *call; | |
178 | ||
179 | /* Create host handle for callback */ | |
180 | host = nlmclnt_lookup_host(&rqstp->rq_addr, | |
181 | rqstp->rq_prot, rqstp->rq_vers); | |
182 | if (host == NULL) | |
183 | return NULL; | |
184 | ||
185 | /* Allocate memory for block, and initialize arguments */ | |
186 | if (!(block = (struct nlm_block *) kmalloc(sizeof(*block), GFP_KERNEL))) | |
187 | goto failed; | |
188 | memset(block, 0, sizeof(*block)); | |
189 | locks_init_lock(&block->b_call.a_args.lock.fl); | |
190 | locks_init_lock(&block->b_call.a_res.lock.fl); | |
191 | ||
192 | if (!nlmclnt_setgrantargs(&block->b_call, lock)) | |
193 | goto failed_free; | |
194 | ||
195 | /* Set notifier function for VFS, and init args */ | |
196 | block->b_call.a_args.lock.fl.fl_lmops = &nlmsvc_lock_operations; | |
197 | block->b_call.a_args.cookie = *cookie; /* see above */ | |
198 | ||
199 | dprintk("lockd: created block %p...\n", block); | |
200 | ||
201 | /* Create and initialize the block */ | |
202 | block->b_daemon = rqstp->rq_server; | |
203 | block->b_host = host; | |
204 | block->b_file = file; | |
205 | ||
206 | /* Add to file's list of blocks */ | |
207 | block->b_fnext = file->f_blocks; | |
208 | file->f_blocks = block; | |
209 | ||
210 | /* Set up RPC arguments for callback */ | |
211 | call = &block->b_call; | |
212 | call->a_host = host; | |
213 | call->a_flags = RPC_TASK_ASYNC; | |
214 | ||
215 | return block; | |
216 | ||
217 | failed_free: | |
218 | kfree(block); | |
219 | failed: | |
220 | nlm_release_host(host); | |
221 | return NULL; | |
222 | } | |
223 | ||
224 | /* | |
225 | * Delete a block. If the lock was cancelled or the grant callback | |
226 | * failed, unlock is set to 1. | |
227 | * It is the caller's responsibility to check whether the file | |
228 | * can be closed hereafter. | |
229 | */ | |
64a318ee | 230 | static int |
1da177e4 LT |
231 | nlmsvc_delete_block(struct nlm_block *block, int unlock) |
232 | { | |
233 | struct file_lock *fl = &block->b_call.a_args.lock.fl; | |
234 | struct nlm_file *file = block->b_file; | |
235 | struct nlm_block **bp; | |
64a318ee | 236 | int status = 0; |
1da177e4 LT |
237 | |
238 | dprintk("lockd: deleting block %p...\n", block); | |
239 | ||
240 | /* Remove block from list */ | |
241 | nlmsvc_remove_block(block); | |
64a318ee BF |
242 | if (unlock) |
243 | status = posix_unblock_lock(file->f_file, fl); | |
1da177e4 LT |
244 | |
245 | /* If the block is in the middle of a GRANT callback, | |
246 | * don't kill it yet. */ | |
247 | if (block->b_incall) { | |
248 | nlmsvc_insert_block(block, NLM_NEVER); | |
249 | block->b_done = 1; | |
64a318ee | 250 | return status; |
1da177e4 LT |
251 | } |
252 | ||
253 | /* Remove block from file's list of blocks */ | |
254 | for (bp = &file->f_blocks; *bp; bp = &(*bp)->b_fnext) { | |
255 | if (*bp == block) { | |
256 | *bp = block->b_fnext; | |
257 | break; | |
258 | } | |
259 | } | |
260 | ||
261 | if (block->b_host) | |
262 | nlm_release_host(block->b_host); | |
263 | nlmclnt_freegrantargs(&block->b_call); | |
264 | kfree(block); | |
64a318ee | 265 | return status; |
1da177e4 LT |
266 | } |
267 | ||
268 | /* | |
269 | * Loop over all blocks and perform the action specified. | |
270 | * (NLM_ACT_CHECK handled by nlmsvc_inspect_file). | |
271 | */ | |
272 | int | |
273 | nlmsvc_traverse_blocks(struct nlm_host *host, struct nlm_file *file, int action) | |
274 | { | |
275 | struct nlm_block *block, *next; | |
64a318ee | 276 | /* XXX: Will everything get cleaned up if we don't unlock here? */ |
1da177e4 LT |
277 | |
278 | down(&file->f_sema); | |
279 | for (block = file->f_blocks; block; block = next) { | |
280 | next = block->b_fnext; | |
281 | if (action == NLM_ACT_MARK) | |
282 | block->b_host->h_inuse = 1; | |
283 | else if (action == NLM_ACT_UNLOCK) { | |
284 | if (host == NULL || host == block->b_host) | |
285 | nlmsvc_delete_block(block, 1); | |
286 | } | |
287 | } | |
288 | up(&file->f_sema); | |
289 | return 0; | |
290 | } | |
291 | ||
292 | /* | |
293 | * Attempt to establish a lock, and if it can't be granted, block it | |
294 | * if required. | |
295 | */ | |
296 | u32 | |
297 | nlmsvc_lock(struct svc_rqst *rqstp, struct nlm_file *file, | |
298 | struct nlm_lock *lock, int wait, struct nlm_cookie *cookie) | |
299 | { | |
300 | struct file_lock *conflock; | |
301 | struct nlm_block *block; | |
302 | int error; | |
303 | ||
304 | dprintk("lockd: nlmsvc_lock(%s/%ld, ty=%d, pi=%d, %Ld-%Ld, bl=%d)\n", | |
305 | file->f_file->f_dentry->d_inode->i_sb->s_id, | |
306 | file->f_file->f_dentry->d_inode->i_ino, | |
307 | lock->fl.fl_type, lock->fl.fl_pid, | |
308 | (long long)lock->fl.fl_start, | |
309 | (long long)lock->fl.fl_end, | |
310 | wait); | |
311 | ||
312 | ||
313 | /* Get existing block (in case client is busy-waiting) */ | |
314 | block = nlmsvc_lookup_block(file, lock, 0); | |
315 | ||
316 | lock->fl.fl_flags |= FL_LOCKD; | |
317 | ||
318 | again: | |
319 | /* Lock file against concurrent access */ | |
320 | down(&file->f_sema); | |
321 | ||
322 | if (!(conflock = posix_test_lock(file->f_file, &lock->fl))) { | |
323 | error = posix_lock_file(file->f_file, &lock->fl); | |
324 | ||
325 | if (block) | |
326 | nlmsvc_delete_block(block, 0); | |
327 | up(&file->f_sema); | |
328 | ||
329 | dprintk("lockd: posix_lock_file returned %d\n", -error); | |
330 | switch(-error) { | |
331 | case 0: | |
332 | return nlm_granted; | |
333 | case EDEADLK: | |
334 | return nlm_deadlock; | |
335 | case EAGAIN: | |
336 | return nlm_lck_denied; | |
337 | default: /* includes ENOLCK */ | |
338 | return nlm_lck_denied_nolocks; | |
339 | } | |
340 | } | |
341 | ||
342 | if (!wait) { | |
343 | up(&file->f_sema); | |
344 | return nlm_lck_denied; | |
345 | } | |
346 | ||
347 | if (posix_locks_deadlock(&lock->fl, conflock)) { | |
348 | up(&file->f_sema); | |
349 | return nlm_deadlock; | |
350 | } | |
351 | ||
352 | /* If we don't have a block, create and initialize it. Then | |
353 | * retry because we may have slept in kmalloc. */ | |
354 | /* We have to release f_sema as nlmsvc_create_block may try to | |
355 | * to claim it while doing host garbage collection */ | |
356 | if (block == NULL) { | |
357 | up(&file->f_sema); | |
358 | dprintk("lockd: blocking on this lock (allocating).\n"); | |
359 | if (!(block = nlmsvc_create_block(rqstp, file, lock, cookie))) | |
360 | return nlm_lck_denied_nolocks; | |
361 | goto again; | |
362 | } | |
363 | ||
364 | /* Append to list of blocked */ | |
365 | nlmsvc_insert_block(block, NLM_NEVER); | |
366 | ||
367 | if (list_empty(&block->b_call.a_args.lock.fl.fl_block)) { | |
368 | /* Now add block to block list of the conflicting lock | |
369 | if we haven't done so. */ | |
370 | dprintk("lockd: blocking on this lock.\n"); | |
371 | posix_block_lock(conflock, &block->b_call.a_args.lock.fl); | |
372 | } | |
373 | ||
374 | up(&file->f_sema); | |
375 | return nlm_lck_blocked; | |
376 | } | |
377 | ||
378 | /* | |
379 | * Test for presence of a conflicting lock. | |
380 | */ | |
381 | u32 | |
382 | nlmsvc_testlock(struct nlm_file *file, struct nlm_lock *lock, | |
383 | struct nlm_lock *conflock) | |
384 | { | |
385 | struct file_lock *fl; | |
386 | ||
387 | dprintk("lockd: nlmsvc_testlock(%s/%ld, ty=%d, %Ld-%Ld)\n", | |
388 | file->f_file->f_dentry->d_inode->i_sb->s_id, | |
389 | file->f_file->f_dentry->d_inode->i_ino, | |
390 | lock->fl.fl_type, | |
391 | (long long)lock->fl.fl_start, | |
392 | (long long)lock->fl.fl_end); | |
393 | ||
394 | if ((fl = posix_test_lock(file->f_file, &lock->fl)) != NULL) { | |
395 | dprintk("lockd: conflicting lock(ty=%d, %Ld-%Ld)\n", | |
396 | fl->fl_type, (long long)fl->fl_start, | |
397 | (long long)fl->fl_end); | |
398 | conflock->caller = "somehost"; /* FIXME */ | |
399 | conflock->oh.len = 0; /* don't return OH info */ | |
7bab377f | 400 | conflock->svid = fl->fl_pid; |
1da177e4 LT |
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; | |
64a318ee | 447 | int status = 0; |
1da177e4 LT |
448 | |
449 | dprintk("lockd: nlmsvc_cancel(%s/%ld, pi=%d, %Ld-%Ld)\n", | |
450 | file->f_file->f_dentry->d_inode->i_sb->s_id, | |
451 | file->f_file->f_dentry->d_inode->i_ino, | |
452 | lock->fl.fl_pid, | |
453 | (long long)lock->fl.fl_start, | |
454 | (long long)lock->fl.fl_end); | |
455 | ||
456 | down(&file->f_sema); | |
457 | if ((block = nlmsvc_lookup_block(file, lock, 1)) != NULL) | |
64a318ee | 458 | status = nlmsvc_delete_block(block, 1); |
1da177e4 | 459 | up(&file->f_sema); |
64a318ee | 460 | return status ? nlm_lck_denied : nlm_granted; |
1da177e4 LT |
461 | } |
462 | ||
463 | /* | |
464 | * Unblock a blocked lock request. This is a callback invoked from the | |
465 | * VFS layer when a lock on which we blocked is removed. | |
466 | * | |
467 | * This function doesn't grant the blocked lock instantly, but rather moves | |
468 | * the block to the head of nlm_blocked where it can be picked up by lockd. | |
469 | */ | |
470 | static void | |
471 | nlmsvc_notify_blocked(struct file_lock *fl) | |
472 | { | |
473 | struct nlm_block **bp, *block; | |
474 | ||
475 | dprintk("lockd: VFS unblock notification for block %p\n", fl); | |
476 | for (bp = &nlm_blocked; (block = *bp) != 0; bp = &block->b_next) { | |
477 | if (nlm_compare_locks(&block->b_call.a_args.lock.fl, fl)) { | |
478 | nlmsvc_insert_block(block, 0); | |
479 | svc_wake_up(block->b_daemon); | |
480 | return; | |
481 | } | |
482 | } | |
483 | ||
484 | printk(KERN_WARNING "lockd: notification for unknown block!\n"); | |
485 | } | |
486 | ||
487 | static int nlmsvc_same_owner(struct file_lock *fl1, struct file_lock *fl2) | |
488 | { | |
489 | return fl1->fl_owner == fl2->fl_owner && fl1->fl_pid == fl2->fl_pid; | |
490 | } | |
491 | ||
492 | struct lock_manager_operations nlmsvc_lock_operations = { | |
493 | .fl_compare_owner = nlmsvc_same_owner, | |
494 | .fl_notify = nlmsvc_notify_blocked, | |
495 | }; | |
496 | ||
497 | /* | |
498 | * Try to claim a lock that was previously blocked. | |
499 | * | |
500 | * Note that we use both the RPC_GRANTED_MSG call _and_ an async | |
501 | * RPC thread when notifying the client. This seems like overkill... | |
502 | * Here's why: | |
503 | * - we don't want to use a synchronous RPC thread, otherwise | |
504 | * we might find ourselves hanging on a dead portmapper. | |
505 | * - Some lockd implementations (e.g. HP) don't react to | |
506 | * RPC_GRANTED calls; they seem to insist on RPC_GRANTED_MSG calls. | |
507 | */ | |
508 | static void | |
509 | nlmsvc_grant_blocked(struct nlm_block *block) | |
510 | { | |
511 | struct nlm_file *file = block->b_file; | |
512 | struct nlm_lock *lock = &block->b_call.a_args.lock; | |
513 | struct file_lock *conflock; | |
514 | int error; | |
515 | ||
516 | dprintk("lockd: grant blocked lock %p\n", block); | |
517 | ||
518 | /* First thing is lock the file */ | |
519 | down(&file->f_sema); | |
520 | ||
521 | /* Unlink block request from list */ | |
522 | nlmsvc_remove_block(block); | |
523 | ||
524 | /* If b_granted is true this means we've been here before. | |
525 | * Just retry the grant callback, possibly refreshing the RPC | |
526 | * binding */ | |
527 | if (block->b_granted) { | |
528 | nlm_rebind_host(block->b_host); | |
529 | goto callback; | |
530 | } | |
531 | ||
532 | /* Try the lock operation again */ | |
533 | if ((conflock = posix_test_lock(file->f_file, &lock->fl)) != NULL) { | |
534 | /* Bummer, we blocked again */ | |
535 | dprintk("lockd: lock still blocked\n"); | |
536 | nlmsvc_insert_block(block, NLM_NEVER); | |
537 | posix_block_lock(conflock, &lock->fl); | |
538 | up(&file->f_sema); | |
539 | return; | |
540 | } | |
541 | ||
542 | /* Alright, no conflicting lock. Now lock it for real. If the | |
543 | * following yields an error, this is most probably due to low | |
544 | * memory. Retry the lock in a few seconds. | |
545 | */ | |
546 | if ((error = posix_lock_file(file->f_file, &lock->fl)) < 0) { | |
547 | printk(KERN_WARNING "lockd: unexpected error %d in %s!\n", | |
548 | -error, __FUNCTION__); | |
549 | nlmsvc_insert_block(block, 10 * HZ); | |
550 | up(&file->f_sema); | |
551 | return; | |
552 | } | |
553 | ||
554 | callback: | |
555 | /* Lock was granted by VFS. */ | |
556 | dprintk("lockd: GRANTing blocked lock.\n"); | |
557 | block->b_granted = 1; | |
558 | block->b_incall = 1; | |
559 | ||
560 | /* Schedule next grant callback in 30 seconds */ | |
561 | nlmsvc_insert_block(block, 30 * HZ); | |
562 | ||
563 | /* Call the client */ | |
564 | nlm_get_host(block->b_call.a_host); | |
565 | if (nlmsvc_async_call(&block->b_call, NLMPROC_GRANTED_MSG, | |
963d8fe5 | 566 | &nlmsvc_grant_ops) < 0) |
1da177e4 LT |
567 | nlm_release_host(block->b_call.a_host); |
568 | up(&file->f_sema); | |
569 | } | |
570 | ||
571 | /* | |
572 | * This is the callback from the RPC layer when the NLM_GRANTED_MSG | |
573 | * RPC call has succeeded or timed out. | |
574 | * Like all RPC callbacks, it is invoked by the rpciod process, so it | |
575 | * better not sleep. Therefore, we put the blocked lock on the nlm_blocked | |
576 | * chain once more in order to have it removed by lockd itself (which can | |
577 | * then sleep on the file semaphore without disrupting e.g. the nfs client). | |
578 | */ | |
963d8fe5 | 579 | static void nlmsvc_grant_callback(struct rpc_task *task, void *data) |
1da177e4 | 580 | { |
963d8fe5 | 581 | struct nlm_rqst *call = data; |
1da177e4 LT |
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 | ||
963d8fe5 TM |
617 | static const struct rpc_call_ops nlmsvc_grant_ops = { |
618 | .rpc_call_done = nlmsvc_grant_callback, | |
619 | }; | |
620 | ||
1da177e4 LT |
621 | /* |
622 | * We received a GRANT_RES callback. Try to find the corresponding | |
623 | * block. | |
624 | */ | |
625 | void | |
626 | nlmsvc_grant_reply(struct svc_rqst *rqstp, struct nlm_cookie *cookie, u32 status) | |
627 | { | |
628 | struct nlm_block *block; | |
629 | struct nlm_file *file; | |
630 | ||
631 | dprintk("grant_reply: looking for cookie %x, host (%08x), s=%d \n", | |
632 | *(unsigned int *)(cookie->data), | |
633 | ntohl(rqstp->rq_addr.sin_addr.s_addr), status); | |
634 | if (!(block = nlmsvc_find_block(cookie, &rqstp->rq_addr))) | |
635 | return; | |
636 | file = block->b_file; | |
637 | ||
638 | file->f_count++; | |
639 | down(&file->f_sema); | |
f232142c BF |
640 | block = nlmsvc_find_block(cookie, &rqstp->rq_addr); |
641 | if (block) { | |
1da177e4 LT |
642 | if (status == NLM_LCK_DENIED_GRACE_PERIOD) { |
643 | /* Try again in a couple of seconds */ | |
644 | nlmsvc_insert_block(block, 10 * HZ); | |
f232142c | 645 | up(&file->f_sema); |
1da177e4 LT |
646 | } else { |
647 | /* Lock is now held by client, or has been rejected. | |
648 | * In both cases, the block should be removed. */ | |
649 | up(&file->f_sema); | |
650 | if (status == NLM_LCK_GRANTED) | |
651 | nlmsvc_delete_block(block, 0); | |
652 | else | |
653 | nlmsvc_delete_block(block, 1); | |
654 | } | |
655 | } | |
1da177e4 LT |
656 | nlm_release_file(file); |
657 | } | |
658 | ||
659 | /* | |
660 | * Retry all blocked locks that have been notified. This is where lockd | |
661 | * picks up locks that can be granted, or grant notifications that must | |
662 | * be retransmitted. | |
663 | */ | |
664 | unsigned long | |
665 | nlmsvc_retry_blocked(void) | |
666 | { | |
667 | struct nlm_block *block; | |
668 | ||
669 | dprintk("nlmsvc_retry_blocked(%p, when=%ld)\n", | |
670 | nlm_blocked, | |
671 | nlm_blocked? nlm_blocked->b_when : 0); | |
672 | while ((block = nlm_blocked) != 0) { | |
673 | if (block->b_when == NLM_NEVER) | |
674 | break; | |
675 | if (time_after(block->b_when,jiffies)) | |
676 | break; | |
677 | dprintk("nlmsvc_retry_blocked(%p, when=%ld, done=%d)\n", | |
678 | block, block->b_when, block->b_done); | |
679 | if (block->b_done) | |
680 | nlmsvc_delete_block(block, 0); | |
681 | else | |
682 | nlmsvc_grant_blocked(block); | |
683 | } | |
684 | ||
685 | if ((block = nlm_blocked) && block->b_when != NLM_NEVER) | |
686 | return (block->b_when - jiffies); | |
687 | ||
688 | return MAX_SCHEDULE_TIMEOUT; | |
689 | } |