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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 | ||
6849c0ca | 42 | static void nlmsvc_release_block(struct nlm_block *block); |
1da177e4 LT |
43 | static void nlmsvc_insert_block(struct nlm_block *block, unsigned long); |
44 | static int nlmsvc_remove_block(struct nlm_block *block); | |
963d8fe5 | 45 | |
5e1abf8c TM |
46 | static int nlmsvc_setgrantargs(struct nlm_rqst *call, struct nlm_lock *lock); |
47 | static void nlmsvc_freegrantargs(struct nlm_rqst *call); | |
963d8fe5 | 48 | static const struct rpc_call_ops nlmsvc_grant_ops; |
1da177e4 LT |
49 | |
50 | /* | |
51 | * The list of blocked locks to retry | |
52 | */ | |
53 | static struct nlm_block * nlm_blocked; | |
54 | ||
55 | /* | |
56 | * Insert a blocked lock into the global list | |
57 | */ | |
58 | static void | |
59 | nlmsvc_insert_block(struct nlm_block *block, unsigned long when) | |
60 | { | |
61 | struct nlm_block **bp, *b; | |
62 | ||
63 | dprintk("lockd: nlmsvc_insert_block(%p, %ld)\n", block, when); | |
6849c0ca | 64 | kref_get(&block->b_count); |
1da177e4 LT |
65 | if (block->b_queued) |
66 | nlmsvc_remove_block(block); | |
67 | bp = &nlm_blocked; | |
68 | if (when != NLM_NEVER) { | |
69 | if ((when += jiffies) == NLM_NEVER) | |
70 | when ++; | |
71 | while ((b = *bp) && time_before_eq(b->b_when,when) && b->b_when != NLM_NEVER) | |
72 | bp = &b->b_next; | |
73 | } else | |
74 | while ((b = *bp) != 0) | |
75 | bp = &b->b_next; | |
76 | ||
77 | block->b_queued = 1; | |
78 | block->b_when = when; | |
79 | block->b_next = b; | |
80 | *bp = block; | |
81 | } | |
82 | ||
83 | /* | |
84 | * Remove a block from the global list | |
85 | */ | |
86 | static int | |
87 | nlmsvc_remove_block(struct nlm_block *block) | |
88 | { | |
89 | struct nlm_block **bp, *b; | |
90 | ||
91 | if (!block->b_queued) | |
92 | return 1; | |
93 | for (bp = &nlm_blocked; (b = *bp) != 0; bp = &b->b_next) { | |
94 | if (b == block) { | |
95 | *bp = block->b_next; | |
96 | block->b_queued = 0; | |
6849c0ca | 97 | nlmsvc_release_block(block); |
1da177e4 LT |
98 | return 1; |
99 | } | |
100 | } | |
101 | ||
102 | return 0; | |
103 | } | |
104 | ||
105 | /* | |
106 | * Find a block for a given lock and optionally remove it from | |
107 | * the list. | |
108 | */ | |
109 | static struct nlm_block * | |
110 | nlmsvc_lookup_block(struct nlm_file *file, struct nlm_lock *lock, int remove) | |
111 | { | |
112 | struct nlm_block **head, *block; | |
113 | struct file_lock *fl; | |
114 | ||
115 | dprintk("lockd: nlmsvc_lookup_block f=%p pd=%d %Ld-%Ld ty=%d\n", | |
116 | file, lock->fl.fl_pid, | |
117 | (long long)lock->fl.fl_start, | |
118 | (long long)lock->fl.fl_end, lock->fl.fl_type); | |
119 | for (head = &nlm_blocked; (block = *head) != 0; head = &block->b_next) { | |
120 | fl = &block->b_call.a_args.lock.fl; | |
121 | dprintk("lockd: check f=%p pd=%d %Ld-%Ld ty=%d cookie=%s\n", | |
122 | block->b_file, fl->fl_pid, | |
123 | (long long)fl->fl_start, | |
124 | (long long)fl->fl_end, fl->fl_type, | |
125 | nlmdbg_cookie2a(&block->b_call.a_args.cookie)); | |
126 | if (block->b_file == file && nlm_compare_locks(fl, &lock->fl)) { | |
127 | if (remove) { | |
128 | *head = block->b_next; | |
129 | block->b_queued = 0; | |
130 | } | |
6849c0ca | 131 | kref_get(&block->b_count); |
1da177e4 LT |
132 | return block; |
133 | } | |
134 | } | |
135 | ||
136 | return NULL; | |
137 | } | |
138 | ||
139 | static inline int nlm_cookie_match(struct nlm_cookie *a, struct nlm_cookie *b) | |
140 | { | |
141 | if(a->len != b->len) | |
142 | return 0; | |
143 | if(memcmp(a->data,b->data,a->len)) | |
144 | return 0; | |
145 | return 1; | |
146 | } | |
147 | ||
148 | /* | |
149 | * Find a block with a given NLM cookie. | |
150 | */ | |
151 | static inline struct nlm_block * | |
152 | nlmsvc_find_block(struct nlm_cookie *cookie, struct sockaddr_in *sin) | |
153 | { | |
154 | struct nlm_block *block; | |
155 | ||
156 | for (block = nlm_blocked; block; block = block->b_next) { | |
157 | dprintk("cookie: head of blocked queue %p, block %p\n", | |
158 | nlm_blocked, block); | |
159 | if (nlm_cookie_match(&block->b_call.a_args.cookie,cookie) | |
160 | && nlm_cmp_addr(sin, &block->b_host->h_addr)) | |
161 | break; | |
162 | } | |
163 | ||
6849c0ca TM |
164 | if (block != NULL) |
165 | kref_get(&block->b_count); | |
1da177e4 LT |
166 | return block; |
167 | } | |
168 | ||
169 | /* | |
170 | * Create a block and initialize it. | |
171 | * | |
172 | * Note: we explicitly set the cookie of the grant reply to that of | |
173 | * the blocked lock request. The spec explicitly mentions that the client | |
174 | * should _not_ rely on the callback containing the same cookie as the | |
175 | * request, but (as I found out later) that's because some implementations | |
176 | * do just this. Never mind the standards comittees, they support our | |
177 | * logging industries. | |
178 | */ | |
179 | static inline struct nlm_block * | |
180 | nlmsvc_create_block(struct svc_rqst *rqstp, struct nlm_file *file, | |
181 | struct nlm_lock *lock, struct nlm_cookie *cookie) | |
182 | { | |
183 | struct nlm_block *block; | |
184 | struct nlm_host *host; | |
185 | struct nlm_rqst *call; | |
186 | ||
187 | /* Create host handle for callback */ | |
686517f1 | 188 | host = nlmsvc_lookup_host(rqstp); |
1da177e4 LT |
189 | if (host == NULL) |
190 | return NULL; | |
191 | ||
192 | /* Allocate memory for block, and initialize arguments */ | |
193 | if (!(block = (struct nlm_block *) kmalloc(sizeof(*block), GFP_KERNEL))) | |
194 | goto failed; | |
195 | memset(block, 0, sizeof(*block)); | |
196 | locks_init_lock(&block->b_call.a_args.lock.fl); | |
197 | locks_init_lock(&block->b_call.a_res.lock.fl); | |
6849c0ca | 198 | kref_init(&block->b_count); |
1da177e4 | 199 | |
5e1abf8c | 200 | if (!nlmsvc_setgrantargs(&block->b_call, lock)) |
1da177e4 LT |
201 | goto failed_free; |
202 | ||
203 | /* Set notifier function for VFS, and init args */ | |
09c7938c | 204 | block->b_call.a_args.lock.fl.fl_flags |= FL_SLEEP; |
1da177e4 LT |
205 | block->b_call.a_args.lock.fl.fl_lmops = &nlmsvc_lock_operations; |
206 | block->b_call.a_args.cookie = *cookie; /* see above */ | |
207 | ||
208 | dprintk("lockd: created block %p...\n", block); | |
209 | ||
210 | /* Create and initialize the block */ | |
211 | block->b_daemon = rqstp->rq_server; | |
212 | block->b_host = host; | |
213 | block->b_file = file; | |
214 | ||
215 | /* Add to file's list of blocks */ | |
216 | block->b_fnext = file->f_blocks; | |
217 | file->f_blocks = block; | |
218 | ||
219 | /* Set up RPC arguments for callback */ | |
220 | call = &block->b_call; | |
221 | call->a_host = host; | |
222 | call->a_flags = RPC_TASK_ASYNC; | |
223 | ||
224 | return block; | |
225 | ||
226 | failed_free: | |
227 | kfree(block); | |
228 | failed: | |
229 | nlm_release_host(host); | |
230 | return NULL; | |
231 | } | |
232 | ||
233 | /* | |
234 | * Delete a block. If the lock was cancelled or the grant callback | |
235 | * failed, unlock is set to 1. | |
236 | * It is the caller's responsibility to check whether the file | |
237 | * can be closed hereafter. | |
238 | */ | |
6849c0ca | 239 | static int nlmsvc_unlink_block(struct nlm_block *block) |
1da177e4 | 240 | { |
09c7938c | 241 | int status; |
6849c0ca | 242 | dprintk("lockd: unlinking block %p...\n", block); |
1da177e4 LT |
243 | |
244 | /* Remove block from list */ | |
6849c0ca | 245 | status = posix_unblock_lock(block->b_file->f_file, &block->b_call.a_args.lock.fl); |
1da177e4 | 246 | nlmsvc_remove_block(block); |
6849c0ca TM |
247 | return status; |
248 | } | |
1da177e4 | 249 | |
6849c0ca TM |
250 | static void nlmsvc_free_block(struct kref *kref) |
251 | { | |
252 | struct nlm_block *block = container_of(kref, struct nlm_block, b_count); | |
253 | struct nlm_file *file = block->b_file; | |
254 | struct nlm_block **bp; | |
255 | ||
256 | dprintk("lockd: freeing block %p...\n", block); | |
1da177e4 LT |
257 | |
258 | /* Remove block from file's list of blocks */ | |
259 | for (bp = &file->f_blocks; *bp; bp = &(*bp)->b_fnext) { | |
260 | if (*bp == block) { | |
261 | *bp = block->b_fnext; | |
262 | break; | |
263 | } | |
264 | } | |
265 | ||
266 | if (block->b_host) | |
267 | nlm_release_host(block->b_host); | |
5e1abf8c | 268 | nlmsvc_freegrantargs(&block->b_call); |
1da177e4 | 269 | kfree(block); |
6849c0ca TM |
270 | } |
271 | ||
272 | static void nlmsvc_release_block(struct nlm_block *block) | |
273 | { | |
274 | if (block != NULL) | |
275 | kref_put(&block->b_count, nlmsvc_free_block); | |
1da177e4 LT |
276 | } |
277 | ||
278 | /* | |
279 | * Loop over all blocks and perform the action specified. | |
280 | * (NLM_ACT_CHECK handled by nlmsvc_inspect_file). | |
281 | */ | |
282 | int | |
283 | nlmsvc_traverse_blocks(struct nlm_host *host, struct nlm_file *file, int action) | |
284 | { | |
285 | struct nlm_block *block, *next; | |
64a318ee | 286 | /* XXX: Will everything get cleaned up if we don't unlock here? */ |
1da177e4 LT |
287 | |
288 | down(&file->f_sema); | |
289 | for (block = file->f_blocks; block; block = next) { | |
290 | next = block->b_fnext; | |
291 | if (action == NLM_ACT_MARK) | |
292 | block->b_host->h_inuse = 1; | |
293 | else if (action == NLM_ACT_UNLOCK) { | |
294 | if (host == NULL || host == block->b_host) | |
6849c0ca | 295 | nlmsvc_unlink_block(block); |
1da177e4 LT |
296 | } |
297 | } | |
298 | up(&file->f_sema); | |
299 | return 0; | |
300 | } | |
301 | ||
5e1abf8c TM |
302 | /* |
303 | * Initialize arguments for GRANTED call. The nlm_rqst structure | |
304 | * has been cleared already. | |
305 | */ | |
306 | static int nlmsvc_setgrantargs(struct nlm_rqst *call, struct nlm_lock *lock) | |
307 | { | |
308 | locks_copy_lock(&call->a_args.lock.fl, &lock->fl); | |
309 | memcpy(&call->a_args.lock.fh, &lock->fh, sizeof(call->a_args.lock.fh)); | |
310 | call->a_args.lock.caller = system_utsname.nodename; | |
311 | call->a_args.lock.oh.len = lock->oh.len; | |
312 | ||
313 | /* set default data area */ | |
314 | call->a_args.lock.oh.data = call->a_owner; | |
315 | call->a_args.lock.svid = lock->fl.fl_pid; | |
316 | ||
317 | if (lock->oh.len > NLMCLNT_OHSIZE) { | |
318 | void *data = kmalloc(lock->oh.len, GFP_KERNEL); | |
319 | if (!data) { | |
320 | nlmsvc_freegrantargs(call); | |
321 | return 0; | |
322 | } | |
323 | call->a_args.lock.oh.data = (u8 *) data; | |
324 | } | |
325 | ||
326 | memcpy(call->a_args.lock.oh.data, lock->oh.data, lock->oh.len); | |
327 | return 1; | |
328 | } | |
329 | ||
330 | static void nlmsvc_freegrantargs(struct nlm_rqst *call) | |
331 | { | |
332 | struct file_lock *fl = &call->a_args.lock.fl; | |
333 | /* | |
334 | * Check whether we allocated memory for the owner. | |
335 | */ | |
336 | if (call->a_args.lock.oh.data != (u8 *) call->a_owner) { | |
337 | kfree(call->a_args.lock.oh.data); | |
338 | } | |
339 | if (fl->fl_ops && fl->fl_ops->fl_release_private) | |
340 | fl->fl_ops->fl_release_private(fl); | |
341 | if (fl->fl_lmops && fl->fl_lmops->fl_release_private) | |
342 | fl->fl_lmops->fl_release_private(fl); | |
343 | } | |
344 | ||
1da177e4 LT |
345 | /* |
346 | * Attempt to establish a lock, and if it can't be granted, block it | |
347 | * if required. | |
348 | */ | |
349 | u32 | |
350 | nlmsvc_lock(struct svc_rqst *rqstp, struct nlm_file *file, | |
351 | struct nlm_lock *lock, int wait, struct nlm_cookie *cookie) | |
352 | { | |
09c7938c | 353 | struct nlm_block *block, *newblock = NULL; |
1da177e4 | 354 | int error; |
15dadef9 | 355 | u32 ret; |
1da177e4 LT |
356 | |
357 | dprintk("lockd: nlmsvc_lock(%s/%ld, ty=%d, pi=%d, %Ld-%Ld, bl=%d)\n", | |
358 | file->f_file->f_dentry->d_inode->i_sb->s_id, | |
359 | file->f_file->f_dentry->d_inode->i_ino, | |
360 | lock->fl.fl_type, lock->fl.fl_pid, | |
361 | (long long)lock->fl.fl_start, | |
362 | (long long)lock->fl.fl_end, | |
363 | wait); | |
364 | ||
365 | ||
09c7938c | 366 | lock->fl.fl_flags &= ~FL_SLEEP; |
1da177e4 LT |
367 | again: |
368 | /* Lock file against concurrent access */ | |
369 | down(&file->f_sema); | |
09c7938c TM |
370 | /* Get existing block (in case client is busy-waiting) */ |
371 | block = nlmsvc_lookup_block(file, lock, 0); | |
372 | if (block == NULL) { | |
373 | if (newblock != NULL) | |
6849c0ca | 374 | lock = &newblock->b_call.a_args.lock; |
09c7938c | 375 | } else |
6849c0ca | 376 | lock = &block->b_call.a_args.lock; |
1da177e4 | 377 | |
a85f193e | 378 | error = posix_lock_file(file->f_file, &lock->fl); |
09c7938c | 379 | lock->fl.fl_flags &= ~FL_SLEEP; |
1da177e4 | 380 | |
a85f193e AA |
381 | dprintk("lockd: posix_lock_file returned %d\n", error); |
382 | ||
09c7938c | 383 | switch(error) { |
1da177e4 | 384 | case 0: |
15dadef9 AA |
385 | ret = nlm_granted; |
386 | goto out; | |
09c7938c TM |
387 | case -EAGAIN: |
388 | break; | |
389 | case -EDEADLK: | |
15dadef9 AA |
390 | ret = nlm_deadlock; |
391 | goto out; | |
1da177e4 | 392 | default: /* includes ENOLCK */ |
15dadef9 AA |
393 | ret = nlm_lck_denied_nolocks; |
394 | goto out; | |
1da177e4 LT |
395 | } |
396 | ||
09c7938c TM |
397 | ret = nlm_lck_denied; |
398 | if (!wait) | |
399 | goto out; | |
400 | ||
401 | ret = nlm_lck_blocked; | |
402 | if (block != NULL) | |
403 | goto out; | |
1da177e4 | 404 | |
1da177e4 LT |
405 | /* If we don't have a block, create and initialize it. Then |
406 | * retry because we may have slept in kmalloc. */ | |
407 | /* We have to release f_sema as nlmsvc_create_block may try to | |
408 | * to claim it while doing host garbage collection */ | |
09c7938c | 409 | if (newblock == NULL) { |
1da177e4 LT |
410 | up(&file->f_sema); |
411 | dprintk("lockd: blocking on this lock (allocating).\n"); | |
09c7938c | 412 | if (!(newblock = nlmsvc_create_block(rqstp, file, lock, cookie))) |
1da177e4 LT |
413 | return nlm_lck_denied_nolocks; |
414 | goto again; | |
415 | } | |
416 | ||
417 | /* Append to list of blocked */ | |
09c7938c | 418 | nlmsvc_insert_block(newblock, NLM_NEVER); |
15dadef9 | 419 | out: |
09c7938c | 420 | up(&file->f_sema); |
6849c0ca TM |
421 | nlmsvc_release_block(newblock); |
422 | nlmsvc_release_block(block); | |
15dadef9 AA |
423 | dprintk("lockd: nlmsvc_lock returned %u\n", ret); |
424 | return ret; | |
1da177e4 LT |
425 | } |
426 | ||
427 | /* | |
428 | * Test for presence of a conflicting lock. | |
429 | */ | |
430 | u32 | |
431 | nlmsvc_testlock(struct nlm_file *file, struct nlm_lock *lock, | |
432 | struct nlm_lock *conflock) | |
433 | { | |
1da177e4 LT |
434 | dprintk("lockd: nlmsvc_testlock(%s/%ld, ty=%d, %Ld-%Ld)\n", |
435 | file->f_file->f_dentry->d_inode->i_sb->s_id, | |
436 | file->f_file->f_dentry->d_inode->i_ino, | |
437 | lock->fl.fl_type, | |
438 | (long long)lock->fl.fl_start, | |
439 | (long long)lock->fl.fl_end); | |
440 | ||
8dc7c311 | 441 | if (posix_test_lock(file->f_file, &lock->fl, &conflock->fl)) { |
1da177e4 | 442 | dprintk("lockd: conflicting lock(ty=%d, %Ld-%Ld)\n", |
8dc7c311 AA |
443 | conflock->fl.fl_type, |
444 | (long long)conflock->fl.fl_start, | |
445 | (long long)conflock->fl.fl_end); | |
1da177e4 LT |
446 | conflock->caller = "somehost"; /* FIXME */ |
447 | conflock->oh.len = 0; /* don't return OH info */ | |
8dc7c311 | 448 | conflock->svid = conflock->fl.fl_pid; |
1da177e4 LT |
449 | return nlm_lck_denied; |
450 | } | |
451 | ||
452 | return nlm_granted; | |
453 | } | |
454 | ||
455 | /* | |
456 | * Remove a lock. | |
457 | * This implies a CANCEL call: We send a GRANT_MSG, the client replies | |
458 | * with a GRANT_RES call which gets lost, and calls UNLOCK immediately | |
459 | * afterwards. In this case the block will still be there, and hence | |
460 | * must be removed. | |
461 | */ | |
462 | u32 | |
463 | nlmsvc_unlock(struct nlm_file *file, struct nlm_lock *lock) | |
464 | { | |
465 | int error; | |
466 | ||
467 | dprintk("lockd: nlmsvc_unlock(%s/%ld, pi=%d, %Ld-%Ld)\n", | |
468 | file->f_file->f_dentry->d_inode->i_sb->s_id, | |
469 | file->f_file->f_dentry->d_inode->i_ino, | |
470 | lock->fl.fl_pid, | |
471 | (long long)lock->fl.fl_start, | |
472 | (long long)lock->fl.fl_end); | |
473 | ||
474 | /* First, cancel any lock that might be there */ | |
475 | nlmsvc_cancel_blocked(file, lock); | |
476 | ||
477 | lock->fl.fl_type = F_UNLCK; | |
478 | error = posix_lock_file(file->f_file, &lock->fl); | |
479 | ||
480 | return (error < 0)? nlm_lck_denied_nolocks : nlm_granted; | |
481 | } | |
482 | ||
483 | /* | |
484 | * Cancel a previously blocked request. | |
485 | * | |
486 | * A cancel request always overrides any grant that may currently | |
487 | * be in progress. | |
488 | * The calling procedure must check whether the file can be closed. | |
489 | */ | |
490 | u32 | |
491 | nlmsvc_cancel_blocked(struct nlm_file *file, struct nlm_lock *lock) | |
492 | { | |
493 | struct nlm_block *block; | |
64a318ee | 494 | int status = 0; |
1da177e4 LT |
495 | |
496 | dprintk("lockd: nlmsvc_cancel(%s/%ld, pi=%d, %Ld-%Ld)\n", | |
497 | file->f_file->f_dentry->d_inode->i_sb->s_id, | |
498 | file->f_file->f_dentry->d_inode->i_ino, | |
499 | lock->fl.fl_pid, | |
500 | (long long)lock->fl.fl_start, | |
501 | (long long)lock->fl.fl_end); | |
502 | ||
503 | down(&file->f_sema); | |
6849c0ca TM |
504 | if ((block = nlmsvc_lookup_block(file, lock, 1)) != NULL) { |
505 | status = nlmsvc_unlink_block(block); | |
506 | nlmsvc_release_block(block); | |
507 | } | |
1da177e4 | 508 | up(&file->f_sema); |
64a318ee | 509 | return status ? nlm_lck_denied : nlm_granted; |
1da177e4 LT |
510 | } |
511 | ||
512 | /* | |
513 | * Unblock a blocked lock request. This is a callback invoked from the | |
514 | * VFS layer when a lock on which we blocked is removed. | |
515 | * | |
516 | * This function doesn't grant the blocked lock instantly, but rather moves | |
517 | * the block to the head of nlm_blocked where it can be picked up by lockd. | |
518 | */ | |
519 | static void | |
520 | nlmsvc_notify_blocked(struct file_lock *fl) | |
521 | { | |
522 | struct nlm_block **bp, *block; | |
523 | ||
524 | dprintk("lockd: VFS unblock notification for block %p\n", fl); | |
525 | for (bp = &nlm_blocked; (block = *bp) != 0; bp = &block->b_next) { | |
526 | if (nlm_compare_locks(&block->b_call.a_args.lock.fl, fl)) { | |
527 | nlmsvc_insert_block(block, 0); | |
528 | svc_wake_up(block->b_daemon); | |
529 | return; | |
530 | } | |
531 | } | |
532 | ||
533 | printk(KERN_WARNING "lockd: notification for unknown block!\n"); | |
534 | } | |
535 | ||
536 | static int nlmsvc_same_owner(struct file_lock *fl1, struct file_lock *fl2) | |
537 | { | |
538 | return fl1->fl_owner == fl2->fl_owner && fl1->fl_pid == fl2->fl_pid; | |
539 | } | |
540 | ||
541 | struct lock_manager_operations nlmsvc_lock_operations = { | |
542 | .fl_compare_owner = nlmsvc_same_owner, | |
543 | .fl_notify = nlmsvc_notify_blocked, | |
544 | }; | |
545 | ||
546 | /* | |
547 | * Try to claim a lock that was previously blocked. | |
548 | * | |
549 | * Note that we use both the RPC_GRANTED_MSG call _and_ an async | |
550 | * RPC thread when notifying the client. This seems like overkill... | |
551 | * Here's why: | |
552 | * - we don't want to use a synchronous RPC thread, otherwise | |
553 | * we might find ourselves hanging on a dead portmapper. | |
554 | * - Some lockd implementations (e.g. HP) don't react to | |
555 | * RPC_GRANTED calls; they seem to insist on RPC_GRANTED_MSG calls. | |
556 | */ | |
557 | static void | |
558 | nlmsvc_grant_blocked(struct nlm_block *block) | |
559 | { | |
560 | struct nlm_file *file = block->b_file; | |
561 | struct nlm_lock *lock = &block->b_call.a_args.lock; | |
1da177e4 LT |
562 | int error; |
563 | ||
564 | dprintk("lockd: grant blocked lock %p\n", block); | |
565 | ||
566 | /* First thing is lock the file */ | |
567 | down(&file->f_sema); | |
568 | ||
569 | /* Unlink block request from list */ | |
6849c0ca | 570 | nlmsvc_unlink_block(block); |
1da177e4 LT |
571 | |
572 | /* If b_granted is true this means we've been here before. | |
573 | * Just retry the grant callback, possibly refreshing the RPC | |
574 | * binding */ | |
575 | if (block->b_granted) { | |
576 | nlm_rebind_host(block->b_host); | |
577 | goto callback; | |
578 | } | |
579 | ||
580 | /* Try the lock operation again */ | |
09c7938c | 581 | lock->fl.fl_flags |= FL_SLEEP; |
5de0e502 | 582 | error = posix_lock_file(file->f_file, &lock->fl); |
09c7938c TM |
583 | lock->fl.fl_flags &= ~FL_SLEEP; |
584 | ||
5de0e502 AA |
585 | switch (error) { |
586 | case 0: | |
587 | break; | |
588 | case -EAGAIN: | |
1da177e4 LT |
589 | dprintk("lockd: lock still blocked\n"); |
590 | nlmsvc_insert_block(block, NLM_NEVER); | |
15dadef9 | 591 | goto out_unlock; |
5de0e502 | 592 | default: |
1da177e4 LT |
593 | printk(KERN_WARNING "lockd: unexpected error %d in %s!\n", |
594 | -error, __FUNCTION__); | |
595 | nlmsvc_insert_block(block, 10 * HZ); | |
15dadef9 | 596 | goto out_unlock; |
1da177e4 LT |
597 | } |
598 | ||
599 | callback: | |
600 | /* Lock was granted by VFS. */ | |
601 | dprintk("lockd: GRANTing blocked lock.\n"); | |
602 | block->b_granted = 1; | |
1da177e4 LT |
603 | |
604 | /* Schedule next grant callback in 30 seconds */ | |
605 | nlmsvc_insert_block(block, 30 * HZ); | |
606 | ||
607 | /* Call the client */ | |
6849c0ca | 608 | kref_get(&block->b_count); |
1da177e4 | 609 | if (nlmsvc_async_call(&block->b_call, NLMPROC_GRANTED_MSG, |
963d8fe5 | 610 | &nlmsvc_grant_ops) < 0) |
6849c0ca | 611 | nlmsvc_release_block(block); |
15dadef9 | 612 | out_unlock: |
1da177e4 LT |
613 | up(&file->f_sema); |
614 | } | |
615 | ||
616 | /* | |
617 | * This is the callback from the RPC layer when the NLM_GRANTED_MSG | |
618 | * RPC call has succeeded or timed out. | |
619 | * Like all RPC callbacks, it is invoked by the rpciod process, so it | |
620 | * better not sleep. Therefore, we put the blocked lock on the nlm_blocked | |
621 | * chain once more in order to have it removed by lockd itself (which can | |
622 | * then sleep on the file semaphore without disrupting e.g. the nfs client). | |
623 | */ | |
963d8fe5 | 624 | static void nlmsvc_grant_callback(struct rpc_task *task, void *data) |
1da177e4 | 625 | { |
963d8fe5 | 626 | struct nlm_rqst *call = data; |
6849c0ca | 627 | struct nlm_block *block = container_of(call, struct nlm_block, b_call); |
1da177e4 | 628 | unsigned long timeout; |
1da177e4 LT |
629 | |
630 | dprintk("lockd: GRANT_MSG RPC callback\n"); | |
1da177e4 LT |
631 | |
632 | /* Technically, we should down the file semaphore here. Since we | |
633 | * move the block towards the head of the queue only, no harm | |
634 | * can be done, though. */ | |
635 | if (task->tk_status < 0) { | |
636 | /* RPC error: Re-insert for retransmission */ | |
637 | timeout = 10 * HZ; | |
638 | } else if (block->b_done) { | |
639 | /* Block already removed, kill it for real */ | |
640 | timeout = 0; | |
641 | } else { | |
642 | /* Call was successful, now wait for client callback */ | |
643 | timeout = 60 * HZ; | |
644 | } | |
645 | nlmsvc_insert_block(block, timeout); | |
646 | svc_wake_up(block->b_daemon); | |
5e1abf8c TM |
647 | } |
648 | ||
649 | void nlmsvc_grant_release(void *data) | |
650 | { | |
651 | nlmsvc_release_block(data); | |
1da177e4 LT |
652 | } |
653 | ||
963d8fe5 TM |
654 | static const struct rpc_call_ops nlmsvc_grant_ops = { |
655 | .rpc_call_done = nlmsvc_grant_callback, | |
5e1abf8c | 656 | .rpc_release = nlmsvc_grant_release, |
963d8fe5 TM |
657 | }; |
658 | ||
1da177e4 LT |
659 | /* |
660 | * We received a GRANT_RES callback. Try to find the corresponding | |
661 | * block. | |
662 | */ | |
663 | void | |
664 | nlmsvc_grant_reply(struct svc_rqst *rqstp, struct nlm_cookie *cookie, u32 status) | |
665 | { | |
666 | struct nlm_block *block; | |
667 | struct nlm_file *file; | |
668 | ||
669 | dprintk("grant_reply: looking for cookie %x, host (%08x), s=%d \n", | |
670 | *(unsigned int *)(cookie->data), | |
671 | ntohl(rqstp->rq_addr.sin_addr.s_addr), status); | |
672 | if (!(block = nlmsvc_find_block(cookie, &rqstp->rq_addr))) | |
673 | return; | |
674 | file = block->b_file; | |
675 | ||
676 | file->f_count++; | |
677 | down(&file->f_sema); | |
f232142c | 678 | if (block) { |
1da177e4 LT |
679 | if (status == NLM_LCK_DENIED_GRACE_PERIOD) { |
680 | /* Try again in a couple of seconds */ | |
681 | nlmsvc_insert_block(block, 10 * HZ); | |
1da177e4 LT |
682 | } else { |
683 | /* Lock is now held by client, or has been rejected. | |
684 | * In both cases, the block should be removed. */ | |
6849c0ca | 685 | nlmsvc_unlink_block(block); |
1da177e4 LT |
686 | } |
687 | } | |
6849c0ca | 688 | up(&file->f_sema); |
1da177e4 | 689 | nlm_release_file(file); |
6849c0ca | 690 | nlmsvc_release_block(block); |
1da177e4 LT |
691 | } |
692 | ||
693 | /* | |
694 | * Retry all blocked locks that have been notified. This is where lockd | |
695 | * picks up locks that can be granted, or grant notifications that must | |
696 | * be retransmitted. | |
697 | */ | |
698 | unsigned long | |
699 | nlmsvc_retry_blocked(void) | |
700 | { | |
701 | struct nlm_block *block; | |
702 | ||
703 | dprintk("nlmsvc_retry_blocked(%p, when=%ld)\n", | |
704 | nlm_blocked, | |
705 | nlm_blocked? nlm_blocked->b_when : 0); | |
706 | while ((block = nlm_blocked) != 0) { | |
707 | if (block->b_when == NLM_NEVER) | |
708 | break; | |
709 | if (time_after(block->b_when,jiffies)) | |
710 | break; | |
711 | dprintk("nlmsvc_retry_blocked(%p, when=%ld, done=%d)\n", | |
712 | block, block->b_when, block->b_done); | |
6849c0ca | 713 | kref_get(&block->b_count); |
1da177e4 | 714 | if (block->b_done) |
6849c0ca | 715 | nlmsvc_unlink_block(block); |
1da177e4 LT |
716 | else |
717 | nlmsvc_grant_blocked(block); | |
6849c0ca | 718 | nlmsvc_release_block(block); |
1da177e4 LT |
719 | } |
720 | ||
721 | if ((block = nlm_blocked) && block->b_when != NLM_NEVER) | |
722 | return (block->b_when - jiffies); | |
723 | ||
724 | return MAX_SCHEDULE_TIMEOUT; | |
725 | } |