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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 | ||
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> | |
32 | ||
33 | #define NLMDBG_FACILITY NLMDBG_SVCLOCK | |
34 | ||
35 | #ifdef CONFIG_LOCKD_V4 | |
36 | #define nlm_deadlock nlm4_deadlock | |
37 | #else | |
38 | #define nlm_deadlock nlm_lck_denied | |
39 | #endif | |
40 | ||
6849c0ca | 41 | static void nlmsvc_release_block(struct nlm_block *block); |
1da177e4 LT |
42 | static void nlmsvc_insert_block(struct nlm_block *block, unsigned long); |
43 | static int nlmsvc_remove_block(struct nlm_block *block); | |
963d8fe5 | 44 | |
5e1abf8c TM |
45 | static int nlmsvc_setgrantargs(struct nlm_rqst *call, struct nlm_lock *lock); |
46 | static void nlmsvc_freegrantargs(struct nlm_rqst *call); | |
963d8fe5 | 47 | static const struct rpc_call_ops nlmsvc_grant_ops; |
1da177e4 LT |
48 | |
49 | /* | |
50 | * The list of blocked locks to retry | |
51 | */ | |
52 | static struct nlm_block * nlm_blocked; | |
53 | ||
54 | /* | |
55 | * Insert a blocked lock into the global list | |
56 | */ | |
57 | static void | |
58 | nlmsvc_insert_block(struct nlm_block *block, unsigned long when) | |
59 | { | |
60 | struct nlm_block **bp, *b; | |
61 | ||
62 | dprintk("lockd: nlmsvc_insert_block(%p, %ld)\n", block, when); | |
6849c0ca | 63 | kref_get(&block->b_count); |
1da177e4 LT |
64 | if (block->b_queued) |
65 | nlmsvc_remove_block(block); | |
66 | bp = &nlm_blocked; | |
67 | if (when != NLM_NEVER) { | |
68 | if ((when += jiffies) == NLM_NEVER) | |
69 | when ++; | |
70 | while ((b = *bp) && time_before_eq(b->b_when,when) && b->b_when != NLM_NEVER) | |
71 | bp = &b->b_next; | |
72 | } else | |
73 | while ((b = *bp) != 0) | |
74 | bp = &b->b_next; | |
75 | ||
76 | block->b_queued = 1; | |
77 | block->b_when = when; | |
78 | block->b_next = b; | |
79 | *bp = block; | |
80 | } | |
81 | ||
82 | /* | |
83 | * Remove a block from the global list | |
84 | */ | |
85 | static int | |
86 | nlmsvc_remove_block(struct nlm_block *block) | |
87 | { | |
88 | struct nlm_block **bp, *b; | |
89 | ||
90 | if (!block->b_queued) | |
91 | return 1; | |
92 | for (bp = &nlm_blocked; (b = *bp) != 0; bp = &b->b_next) { | |
93 | if (b == block) { | |
94 | *bp = block->b_next; | |
95 | block->b_queued = 0; | |
6849c0ca | 96 | nlmsvc_release_block(block); |
1da177e4 LT |
97 | return 1; |
98 | } | |
99 | } | |
100 | ||
101 | return 0; | |
102 | } | |
103 | ||
104 | /* | |
d9f6eb75 | 105 | * Find a block for a given lock |
1da177e4 LT |
106 | */ |
107 | static struct nlm_block * | |
d9f6eb75 | 108 | nlmsvc_lookup_block(struct nlm_file *file, struct nlm_lock *lock) |
1da177e4 LT |
109 | { |
110 | struct nlm_block **head, *block; | |
111 | struct file_lock *fl; | |
112 | ||
113 | dprintk("lockd: nlmsvc_lookup_block f=%p pd=%d %Ld-%Ld ty=%d\n", | |
114 | file, lock->fl.fl_pid, | |
115 | (long long)lock->fl.fl_start, | |
116 | (long long)lock->fl.fl_end, lock->fl.fl_type); | |
117 | for (head = &nlm_blocked; (block = *head) != 0; head = &block->b_next) { | |
92737230 | 118 | fl = &block->b_call->a_args.lock.fl; |
1da177e4 LT |
119 | dprintk("lockd: check f=%p pd=%d %Ld-%Ld ty=%d cookie=%s\n", |
120 | block->b_file, fl->fl_pid, | |
121 | (long long)fl->fl_start, | |
122 | (long long)fl->fl_end, fl->fl_type, | |
92737230 | 123 | nlmdbg_cookie2a(&block->b_call->a_args.cookie)); |
1da177e4 | 124 | if (block->b_file == file && nlm_compare_locks(fl, &lock->fl)) { |
6849c0ca | 125 | kref_get(&block->b_count); |
1da177e4 LT |
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); | |
92737230 | 153 | if (nlm_cookie_match(&block->b_call->a_args.cookie,cookie) |
1da177e4 LT |
154 | && nlm_cmp_addr(sin, &block->b_host->h_addr)) |
155 | break; | |
156 | } | |
157 | ||
6849c0ca TM |
158 | if (block != NULL) |
159 | kref_get(&block->b_count); | |
1da177e4 LT |
160 | return block; |
161 | } | |
162 | ||
163 | /* | |
164 | * Create a block and initialize it. | |
165 | * | |
166 | * Note: we explicitly set the cookie of the grant reply to that of | |
167 | * the blocked lock request. The spec explicitly mentions that the client | |
168 | * should _not_ rely on the callback containing the same cookie as the | |
169 | * request, but (as I found out later) that's because some implementations | |
170 | * do just this. Never mind the standards comittees, they support our | |
171 | * logging industries. | |
172 | */ | |
173 | static inline struct nlm_block * | |
174 | nlmsvc_create_block(struct svc_rqst *rqstp, struct nlm_file *file, | |
175 | struct nlm_lock *lock, struct nlm_cookie *cookie) | |
176 | { | |
177 | struct nlm_block *block; | |
178 | struct nlm_host *host; | |
92737230 | 179 | struct nlm_rqst *call = NULL; |
1da177e4 LT |
180 | |
181 | /* Create host handle for callback */ | |
db4e4c9a | 182 | host = nlmsvc_lookup_host(rqstp, lock->caller, lock->len); |
1da177e4 LT |
183 | if (host == NULL) |
184 | return NULL; | |
185 | ||
92737230 TM |
186 | call = nlm_alloc_call(host); |
187 | if (call == NULL) | |
188 | return NULL; | |
189 | ||
1da177e4 | 190 | /* Allocate memory for block, and initialize arguments */ |
92737230 TM |
191 | block = kzalloc(sizeof(*block), GFP_KERNEL); |
192 | if (block == NULL) | |
1da177e4 | 193 | goto failed; |
6849c0ca | 194 | kref_init(&block->b_count); |
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; | |
202 | call->a_args.cookie = *cookie; /* see above */ | |
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; | |
d9f6eb75 | 210 | file->f_count++; |
1da177e4 LT |
211 | |
212 | /* Add to file's list of blocks */ | |
213 | block->b_fnext = file->f_blocks; | |
214 | file->f_blocks = block; | |
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 | ||
223 | failed_free: | |
224 | kfree(block); | |
225 | failed: | |
92737230 | 226 | nlm_release_call(call); |
1da177e4 LT |
227 | return NULL; |
228 | } | |
229 | ||
230 | /* | |
231 | * Delete a block. If the lock was cancelled or the grant callback | |
232 | * failed, unlock is set to 1. | |
233 | * It is the caller's responsibility to check whether the file | |
234 | * can be closed hereafter. | |
235 | */ | |
6849c0ca | 236 | static int nlmsvc_unlink_block(struct nlm_block *block) |
1da177e4 | 237 | { |
09c7938c | 238 | int status; |
6849c0ca | 239 | dprintk("lockd: unlinking block %p...\n", block); |
1da177e4 LT |
240 | |
241 | /* Remove block from list */ | |
92737230 | 242 | status = posix_unblock_lock(block->b_file->f_file, &block->b_call->a_args.lock.fl); |
1da177e4 | 243 | nlmsvc_remove_block(block); |
6849c0ca TM |
244 | return status; |
245 | } | |
1da177e4 | 246 | |
6849c0ca TM |
247 | static void nlmsvc_free_block(struct kref *kref) |
248 | { | |
249 | struct nlm_block *block = container_of(kref, struct nlm_block, b_count); | |
250 | struct nlm_file *file = block->b_file; | |
251 | struct nlm_block **bp; | |
252 | ||
253 | dprintk("lockd: freeing block %p...\n", block); | |
1da177e4 | 254 | |
d9f6eb75 | 255 | down(&file->f_sema); |
1da177e4 LT |
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 | } | |
d9f6eb75 | 263 | up(&file->f_sema); |
1da177e4 | 264 | |
92737230 TM |
265 | nlmsvc_freegrantargs(block->b_call); |
266 | nlm_release_call(block->b_call); | |
d9f6eb75 | 267 | nlm_release_file(block->b_file); |
1da177e4 | 268 | kfree(block); |
6849c0ca TM |
269 | } |
270 | ||
271 | static void nlmsvc_release_block(struct nlm_block *block) | |
272 | { | |
273 | if (block != NULL) | |
274 | kref_put(&block->b_count, nlmsvc_free_block); | |
1da177e4 LT |
275 | } |
276 | ||
d9f6eb75 TM |
277 | static void nlmsvc_act_mark(struct nlm_host *host, struct nlm_file *file) |
278 | { | |
279 | struct nlm_block *block; | |
280 | ||
281 | down(&file->f_sema); | |
282 | for (block = file->f_blocks; block != NULL; block = block->b_fnext) | |
283 | block->b_host->h_inuse = 1; | |
284 | up(&file->f_sema); | |
285 | } | |
286 | ||
287 | static void nlmsvc_act_unlock(struct nlm_host *host, struct nlm_file *file) | |
288 | { | |
289 | struct nlm_block *block; | |
290 | ||
291 | restart: | |
292 | down(&file->f_sema); | |
293 | for (block = file->f_blocks; block != NULL; block = block->b_fnext) { | |
294 | if (host != NULL && host != block->b_host) | |
295 | continue; | |
296 | if (!block->b_queued) | |
297 | continue; | |
298 | kref_get(&block->b_count); | |
299 | up(&file->f_sema); | |
300 | nlmsvc_unlink_block(block); | |
301 | nlmsvc_release_block(block); | |
302 | goto restart; | |
303 | } | |
304 | up(&file->f_sema); | |
305 | } | |
306 | ||
1da177e4 LT |
307 | /* |
308 | * Loop over all blocks and perform the action specified. | |
309 | * (NLM_ACT_CHECK handled by nlmsvc_inspect_file). | |
310 | */ | |
f3ee439f | 311 | void |
1da177e4 LT |
312 | nlmsvc_traverse_blocks(struct nlm_host *host, struct nlm_file *file, int action) |
313 | { | |
d9f6eb75 TM |
314 | if (action == NLM_ACT_MARK) |
315 | nlmsvc_act_mark(host, file); | |
316 | else | |
317 | nlmsvc_act_unlock(host, file); | |
1da177e4 LT |
318 | } |
319 | ||
5e1abf8c TM |
320 | /* |
321 | * Initialize arguments for GRANTED call. The nlm_rqst structure | |
322 | * has been cleared already. | |
323 | */ | |
324 | static int nlmsvc_setgrantargs(struct nlm_rqst *call, struct nlm_lock *lock) | |
325 | { | |
326 | locks_copy_lock(&call->a_args.lock.fl, &lock->fl); | |
327 | memcpy(&call->a_args.lock.fh, &lock->fh, sizeof(call->a_args.lock.fh)); | |
e9ff3990 | 328 | call->a_args.lock.caller = utsname()->nodename; |
5e1abf8c TM |
329 | call->a_args.lock.oh.len = lock->oh.len; |
330 | ||
331 | /* set default data area */ | |
332 | call->a_args.lock.oh.data = call->a_owner; | |
333 | call->a_args.lock.svid = lock->fl.fl_pid; | |
334 | ||
335 | if (lock->oh.len > NLMCLNT_OHSIZE) { | |
336 | void *data = kmalloc(lock->oh.len, GFP_KERNEL); | |
92737230 | 337 | if (!data) |
5e1abf8c | 338 | return 0; |
5e1abf8c TM |
339 | call->a_args.lock.oh.data = (u8 *) data; |
340 | } | |
341 | ||
342 | memcpy(call->a_args.lock.oh.data, lock->oh.data, lock->oh.len); | |
343 | return 1; | |
344 | } | |
345 | ||
346 | static void nlmsvc_freegrantargs(struct nlm_rqst *call) | |
347 | { | |
92737230 | 348 | if (call->a_args.lock.oh.data != call->a_owner) |
5e1abf8c | 349 | kfree(call->a_args.lock.oh.data); |
5e1abf8c TM |
350 | } |
351 | ||
1da177e4 LT |
352 | /* |
353 | * Attempt to establish a lock, and if it can't be granted, block it | |
354 | * if required. | |
355 | */ | |
356 | u32 | |
357 | nlmsvc_lock(struct svc_rqst *rqstp, struct nlm_file *file, | |
358 | struct nlm_lock *lock, int wait, struct nlm_cookie *cookie) | |
359 | { | |
09c7938c | 360 | struct nlm_block *block, *newblock = NULL; |
1da177e4 | 361 | int error; |
15dadef9 | 362 | u32 ret; |
1da177e4 LT |
363 | |
364 | dprintk("lockd: nlmsvc_lock(%s/%ld, ty=%d, pi=%d, %Ld-%Ld, bl=%d)\n", | |
365 | file->f_file->f_dentry->d_inode->i_sb->s_id, | |
366 | file->f_file->f_dentry->d_inode->i_ino, | |
367 | lock->fl.fl_type, lock->fl.fl_pid, | |
368 | (long long)lock->fl.fl_start, | |
369 | (long long)lock->fl.fl_end, | |
370 | wait); | |
371 | ||
372 | ||
09c7938c | 373 | lock->fl.fl_flags &= ~FL_SLEEP; |
1da177e4 LT |
374 | again: |
375 | /* Lock file against concurrent access */ | |
376 | down(&file->f_sema); | |
09c7938c | 377 | /* Get existing block (in case client is busy-waiting) */ |
d9f6eb75 | 378 | block = nlmsvc_lookup_block(file, lock); |
09c7938c TM |
379 | if (block == NULL) { |
380 | if (newblock != NULL) | |
92737230 | 381 | lock = &newblock->b_call->a_args.lock; |
09c7938c | 382 | } else |
92737230 | 383 | lock = &block->b_call->a_args.lock; |
1da177e4 | 384 | |
a85f193e | 385 | error = posix_lock_file(file->f_file, &lock->fl); |
09c7938c | 386 | lock->fl.fl_flags &= ~FL_SLEEP; |
1da177e4 | 387 | |
a85f193e AA |
388 | dprintk("lockd: posix_lock_file returned %d\n", error); |
389 | ||
09c7938c | 390 | switch(error) { |
1da177e4 | 391 | case 0: |
15dadef9 AA |
392 | ret = nlm_granted; |
393 | goto out; | |
09c7938c TM |
394 | case -EAGAIN: |
395 | break; | |
396 | case -EDEADLK: | |
15dadef9 AA |
397 | ret = nlm_deadlock; |
398 | goto out; | |
1da177e4 | 399 | default: /* includes ENOLCK */ |
15dadef9 AA |
400 | ret = nlm_lck_denied_nolocks; |
401 | goto out; | |
1da177e4 LT |
402 | } |
403 | ||
09c7938c TM |
404 | ret = nlm_lck_denied; |
405 | if (!wait) | |
406 | goto out; | |
407 | ||
408 | ret = nlm_lck_blocked; | |
409 | if (block != NULL) | |
410 | goto out; | |
1da177e4 | 411 | |
1da177e4 LT |
412 | /* If we don't have a block, create and initialize it. Then |
413 | * retry because we may have slept in kmalloc. */ | |
414 | /* We have to release f_sema as nlmsvc_create_block may try to | |
415 | * to claim it while doing host garbage collection */ | |
09c7938c | 416 | if (newblock == NULL) { |
1da177e4 LT |
417 | up(&file->f_sema); |
418 | dprintk("lockd: blocking on this lock (allocating).\n"); | |
09c7938c | 419 | if (!(newblock = nlmsvc_create_block(rqstp, file, lock, cookie))) |
1da177e4 LT |
420 | return nlm_lck_denied_nolocks; |
421 | goto again; | |
422 | } | |
423 | ||
424 | /* Append to list of blocked */ | |
09c7938c | 425 | nlmsvc_insert_block(newblock, NLM_NEVER); |
15dadef9 | 426 | out: |
09c7938c | 427 | up(&file->f_sema); |
6849c0ca TM |
428 | nlmsvc_release_block(newblock); |
429 | nlmsvc_release_block(block); | |
15dadef9 AA |
430 | dprintk("lockd: nlmsvc_lock returned %u\n", ret); |
431 | return ret; | |
1da177e4 LT |
432 | } |
433 | ||
434 | /* | |
435 | * Test for presence of a conflicting lock. | |
436 | */ | |
437 | u32 | |
438 | nlmsvc_testlock(struct nlm_file *file, struct nlm_lock *lock, | |
439 | struct nlm_lock *conflock) | |
440 | { | |
1da177e4 LT |
441 | dprintk("lockd: nlmsvc_testlock(%s/%ld, ty=%d, %Ld-%Ld)\n", |
442 | file->f_file->f_dentry->d_inode->i_sb->s_id, | |
443 | file->f_file->f_dentry->d_inode->i_ino, | |
444 | lock->fl.fl_type, | |
445 | (long long)lock->fl.fl_start, | |
446 | (long long)lock->fl.fl_end); | |
447 | ||
8dc7c311 | 448 | if (posix_test_lock(file->f_file, &lock->fl, &conflock->fl)) { |
1da177e4 | 449 | dprintk("lockd: conflicting lock(ty=%d, %Ld-%Ld)\n", |
8dc7c311 AA |
450 | conflock->fl.fl_type, |
451 | (long long)conflock->fl.fl_start, | |
452 | (long long)conflock->fl.fl_end); | |
1da177e4 | 453 | conflock->caller = "somehost"; /* FIXME */ |
db4e4c9a | 454 | conflock->len = strlen(conflock->caller); |
1da177e4 | 455 | conflock->oh.len = 0; /* don't return OH info */ |
8dc7c311 | 456 | conflock->svid = conflock->fl.fl_pid; |
1da177e4 LT |
457 | return nlm_lck_denied; |
458 | } | |
459 | ||
460 | return nlm_granted; | |
461 | } | |
462 | ||
463 | /* | |
464 | * Remove a lock. | |
465 | * This implies a CANCEL call: We send a GRANT_MSG, the client replies | |
466 | * with a GRANT_RES call which gets lost, and calls UNLOCK immediately | |
467 | * afterwards. In this case the block will still be there, and hence | |
468 | * must be removed. | |
469 | */ | |
470 | u32 | |
471 | nlmsvc_unlock(struct nlm_file *file, struct nlm_lock *lock) | |
472 | { | |
473 | int error; | |
474 | ||
475 | dprintk("lockd: nlmsvc_unlock(%s/%ld, pi=%d, %Ld-%Ld)\n", | |
476 | file->f_file->f_dentry->d_inode->i_sb->s_id, | |
477 | file->f_file->f_dentry->d_inode->i_ino, | |
478 | lock->fl.fl_pid, | |
479 | (long long)lock->fl.fl_start, | |
480 | (long long)lock->fl.fl_end); | |
481 | ||
482 | /* First, cancel any lock that might be there */ | |
483 | nlmsvc_cancel_blocked(file, lock); | |
484 | ||
485 | lock->fl.fl_type = F_UNLCK; | |
486 | error = posix_lock_file(file->f_file, &lock->fl); | |
487 | ||
488 | return (error < 0)? nlm_lck_denied_nolocks : nlm_granted; | |
489 | } | |
490 | ||
491 | /* | |
492 | * Cancel a previously blocked request. | |
493 | * | |
494 | * A cancel request always overrides any grant that may currently | |
495 | * be in progress. | |
496 | * The calling procedure must check whether the file can be closed. | |
497 | */ | |
498 | u32 | |
499 | nlmsvc_cancel_blocked(struct nlm_file *file, struct nlm_lock *lock) | |
500 | { | |
501 | struct nlm_block *block; | |
64a318ee | 502 | int status = 0; |
1da177e4 LT |
503 | |
504 | dprintk("lockd: nlmsvc_cancel(%s/%ld, pi=%d, %Ld-%Ld)\n", | |
505 | file->f_file->f_dentry->d_inode->i_sb->s_id, | |
506 | file->f_file->f_dentry->d_inode->i_ino, | |
507 | lock->fl.fl_pid, | |
508 | (long long)lock->fl.fl_start, | |
509 | (long long)lock->fl.fl_end); | |
510 | ||
511 | down(&file->f_sema); | |
d9f6eb75 TM |
512 | block = nlmsvc_lookup_block(file, lock); |
513 | up(&file->f_sema); | |
514 | if (block != NULL) { | |
6849c0ca TM |
515 | status = nlmsvc_unlink_block(block); |
516 | nlmsvc_release_block(block); | |
517 | } | |
64a318ee | 518 | return status ? nlm_lck_denied : nlm_granted; |
1da177e4 LT |
519 | } |
520 | ||
521 | /* | |
522 | * Unblock a blocked lock request. This is a callback invoked from the | |
523 | * VFS layer when a lock on which we blocked is removed. | |
524 | * | |
525 | * This function doesn't grant the blocked lock instantly, but rather moves | |
526 | * the block to the head of nlm_blocked where it can be picked up by lockd. | |
527 | */ | |
528 | static void | |
529 | nlmsvc_notify_blocked(struct file_lock *fl) | |
530 | { | |
531 | struct nlm_block **bp, *block; | |
532 | ||
533 | dprintk("lockd: VFS unblock notification for block %p\n", fl); | |
534 | for (bp = &nlm_blocked; (block = *bp) != 0; bp = &block->b_next) { | |
92737230 | 535 | if (nlm_compare_locks(&block->b_call->a_args.lock.fl, fl)) { |
1da177e4 LT |
536 | nlmsvc_insert_block(block, 0); |
537 | svc_wake_up(block->b_daemon); | |
538 | return; | |
539 | } | |
540 | } | |
541 | ||
542 | printk(KERN_WARNING "lockd: notification for unknown block!\n"); | |
543 | } | |
544 | ||
545 | static int nlmsvc_same_owner(struct file_lock *fl1, struct file_lock *fl2) | |
546 | { | |
547 | return fl1->fl_owner == fl2->fl_owner && fl1->fl_pid == fl2->fl_pid; | |
548 | } | |
549 | ||
550 | struct lock_manager_operations nlmsvc_lock_operations = { | |
551 | .fl_compare_owner = nlmsvc_same_owner, | |
552 | .fl_notify = nlmsvc_notify_blocked, | |
553 | }; | |
554 | ||
555 | /* | |
556 | * Try to claim a lock that was previously blocked. | |
557 | * | |
558 | * Note that we use both the RPC_GRANTED_MSG call _and_ an async | |
559 | * RPC thread when notifying the client. This seems like overkill... | |
560 | * Here's why: | |
561 | * - we don't want to use a synchronous RPC thread, otherwise | |
562 | * we might find ourselves hanging on a dead portmapper. | |
563 | * - Some lockd implementations (e.g. HP) don't react to | |
564 | * RPC_GRANTED calls; they seem to insist on RPC_GRANTED_MSG calls. | |
565 | */ | |
566 | static void | |
567 | nlmsvc_grant_blocked(struct nlm_block *block) | |
568 | { | |
569 | struct nlm_file *file = block->b_file; | |
92737230 | 570 | struct nlm_lock *lock = &block->b_call->a_args.lock; |
1da177e4 LT |
571 | int error; |
572 | ||
573 | dprintk("lockd: grant blocked lock %p\n", block); | |
574 | ||
1da177e4 | 575 | /* Unlink block request from list */ |
6849c0ca | 576 | nlmsvc_unlink_block(block); |
1da177e4 LT |
577 | |
578 | /* If b_granted is true this means we've been here before. | |
579 | * Just retry the grant callback, possibly refreshing the RPC | |
580 | * binding */ | |
581 | if (block->b_granted) { | |
582 | nlm_rebind_host(block->b_host); | |
583 | goto callback; | |
584 | } | |
585 | ||
586 | /* Try the lock operation again */ | |
09c7938c | 587 | lock->fl.fl_flags |= FL_SLEEP; |
5de0e502 | 588 | error = posix_lock_file(file->f_file, &lock->fl); |
09c7938c TM |
589 | lock->fl.fl_flags &= ~FL_SLEEP; |
590 | ||
5de0e502 AA |
591 | switch (error) { |
592 | case 0: | |
593 | break; | |
594 | case -EAGAIN: | |
1da177e4 LT |
595 | dprintk("lockd: lock still blocked\n"); |
596 | nlmsvc_insert_block(block, NLM_NEVER); | |
d9f6eb75 | 597 | return; |
5de0e502 | 598 | default: |
1da177e4 LT |
599 | printk(KERN_WARNING "lockd: unexpected error %d in %s!\n", |
600 | -error, __FUNCTION__); | |
601 | nlmsvc_insert_block(block, 10 * HZ); | |
d9f6eb75 | 602 | return; |
1da177e4 LT |
603 | } |
604 | ||
605 | callback: | |
606 | /* Lock was granted by VFS. */ | |
607 | dprintk("lockd: GRANTing blocked lock.\n"); | |
608 | block->b_granted = 1; | |
1da177e4 LT |
609 | |
610 | /* Schedule next grant callback in 30 seconds */ | |
611 | nlmsvc_insert_block(block, 30 * HZ); | |
612 | ||
613 | /* Call the client */ | |
6849c0ca | 614 | kref_get(&block->b_count); |
92737230 | 615 | if (nlm_async_call(block->b_call, NLMPROC_GRANTED_MSG, |
963d8fe5 | 616 | &nlmsvc_grant_ops) < 0) |
6849c0ca | 617 | nlmsvc_release_block(block); |
1da177e4 LT |
618 | } |
619 | ||
620 | /* | |
621 | * This is the callback from the RPC layer when the NLM_GRANTED_MSG | |
622 | * RPC call has succeeded or timed out. | |
623 | * Like all RPC callbacks, it is invoked by the rpciod process, so it | |
624 | * better not sleep. Therefore, we put the blocked lock on the nlm_blocked | |
625 | * chain once more in order to have it removed by lockd itself (which can | |
626 | * then sleep on the file semaphore without disrupting e.g. the nfs client). | |
627 | */ | |
963d8fe5 | 628 | static void nlmsvc_grant_callback(struct rpc_task *task, void *data) |
1da177e4 | 629 | { |
963d8fe5 | 630 | struct nlm_rqst *call = data; |
92737230 | 631 | struct nlm_block *block = call->a_block; |
1da177e4 | 632 | unsigned long timeout; |
1da177e4 LT |
633 | |
634 | dprintk("lockd: GRANT_MSG RPC callback\n"); | |
1da177e4 LT |
635 | |
636 | /* Technically, we should down the file semaphore here. Since we | |
637 | * move the block towards the head of the queue only, no harm | |
638 | * can be done, though. */ | |
639 | if (task->tk_status < 0) { | |
640 | /* RPC error: Re-insert for retransmission */ | |
641 | timeout = 10 * HZ; | |
1da177e4 LT |
642 | } else { |
643 | /* Call was successful, now wait for client callback */ | |
644 | timeout = 60 * HZ; | |
645 | } | |
646 | nlmsvc_insert_block(block, timeout); | |
647 | svc_wake_up(block->b_daemon); | |
5e1abf8c TM |
648 | } |
649 | ||
ec535ce1 | 650 | static void nlmsvc_grant_release(void *data) |
5e1abf8c | 651 | { |
6041b791 TM |
652 | struct nlm_rqst *call = data; |
653 | ||
654 | nlmsvc_release_block(call->a_block); | |
1da177e4 LT |
655 | } |
656 | ||
963d8fe5 TM |
657 | static const struct rpc_call_ops nlmsvc_grant_ops = { |
658 | .rpc_call_done = nlmsvc_grant_callback, | |
5e1abf8c | 659 | .rpc_release = nlmsvc_grant_release, |
963d8fe5 TM |
660 | }; |
661 | ||
1da177e4 LT |
662 | /* |
663 | * We received a GRANT_RES callback. Try to find the corresponding | |
664 | * block. | |
665 | */ | |
666 | void | |
667 | nlmsvc_grant_reply(struct svc_rqst *rqstp, struct nlm_cookie *cookie, u32 status) | |
668 | { | |
669 | struct nlm_block *block; | |
670 | struct nlm_file *file; | |
671 | ||
672 | dprintk("grant_reply: looking for cookie %x, host (%08x), s=%d \n", | |
673 | *(unsigned int *)(cookie->data), | |
674 | ntohl(rqstp->rq_addr.sin_addr.s_addr), status); | |
675 | if (!(block = nlmsvc_find_block(cookie, &rqstp->rq_addr))) | |
676 | return; | |
677 | file = block->b_file; | |
678 | ||
f232142c | 679 | if (block) { |
1da177e4 LT |
680 | if (status == NLM_LCK_DENIED_GRACE_PERIOD) { |
681 | /* Try again in a couple of seconds */ | |
682 | nlmsvc_insert_block(block, 10 * HZ); | |
1da177e4 LT |
683 | } else { |
684 | /* Lock is now held by client, or has been rejected. | |
685 | * In both cases, the block should be removed. */ | |
6849c0ca | 686 | nlmsvc_unlink_block(block); |
1da177e4 LT |
687 | } |
688 | } | |
6849c0ca | 689 | nlmsvc_release_block(block); |
1da177e4 LT |
690 | } |
691 | ||
692 | /* | |
693 | * Retry all blocked locks that have been notified. This is where lockd | |
694 | * picks up locks that can be granted, or grant notifications that must | |
695 | * be retransmitted. | |
696 | */ | |
697 | unsigned long | |
698 | nlmsvc_retry_blocked(void) | |
699 | { | |
700 | struct nlm_block *block; | |
701 | ||
702 | dprintk("nlmsvc_retry_blocked(%p, when=%ld)\n", | |
703 | nlm_blocked, | |
704 | nlm_blocked? nlm_blocked->b_when : 0); | |
705 | while ((block = nlm_blocked) != 0) { | |
706 | if (block->b_when == NLM_NEVER) | |
707 | break; | |
708 | if (time_after(block->b_when,jiffies)) | |
709 | break; | |
f3d43c76 BF |
710 | dprintk("nlmsvc_retry_blocked(%p, when=%ld)\n", |
711 | block, block->b_when); | |
6849c0ca | 712 | kref_get(&block->b_count); |
f3d43c76 | 713 | nlmsvc_grant_blocked(block); |
6849c0ca | 714 | nlmsvc_release_block(block); |
1da177e4 LT |
715 | } |
716 | ||
717 | if ((block = nlm_blocked) && block->b_when != NLM_NEVER) | |
718 | return (block->b_when - jiffies); | |
719 | ||
720 | return MAX_SCHEDULE_TIMEOUT; | |
721 | } |