Commit | Line | Data |
---|---|---|
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) { | |
92737230 | 120 | fl = &block->b_call->a_args.lock.fl; |
1da177e4 LT |
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, | |
92737230 | 125 | nlmdbg_cookie2a(&block->b_call->a_args.cookie)); |
1da177e4 LT |
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); | |
92737230 | 159 | if (nlm_cookie_match(&block->b_call->a_args.cookie,cookie) |
1da177e4 LT |
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; | |
92737230 | 185 | struct nlm_rqst *call = NULL; |
1da177e4 LT |
186 | |
187 | /* Create host handle for callback */ | |
686517f1 | 188 | host = nlmsvc_lookup_host(rqstp); |
1da177e4 LT |
189 | if (host == NULL) |
190 | return NULL; | |
191 | ||
92737230 TM |
192 | call = nlm_alloc_call(host); |
193 | if (call == NULL) | |
194 | return NULL; | |
195 | ||
1da177e4 | 196 | /* Allocate memory for block, and initialize arguments */ |
92737230 TM |
197 | block = kzalloc(sizeof(*block), GFP_KERNEL); |
198 | if (block == NULL) | |
1da177e4 | 199 | goto failed; |
6849c0ca | 200 | kref_init(&block->b_count); |
1da177e4 | 201 | |
92737230 | 202 | if (!nlmsvc_setgrantargs(call, lock)) |
1da177e4 LT |
203 | goto failed_free; |
204 | ||
205 | /* Set notifier function for VFS, and init args */ | |
92737230 TM |
206 | call->a_args.lock.fl.fl_flags |= FL_SLEEP; |
207 | call->a_args.lock.fl.fl_lmops = &nlmsvc_lock_operations; | |
208 | call->a_args.cookie = *cookie; /* see above */ | |
1da177e4 LT |
209 | |
210 | dprintk("lockd: created block %p...\n", block); | |
211 | ||
212 | /* Create and initialize the block */ | |
213 | block->b_daemon = rqstp->rq_server; | |
214 | block->b_host = host; | |
215 | block->b_file = file; | |
216 | ||
217 | /* Add to file's list of blocks */ | |
218 | block->b_fnext = file->f_blocks; | |
219 | file->f_blocks = block; | |
220 | ||
221 | /* Set up RPC arguments for callback */ | |
92737230 | 222 | block->b_call = call; |
1da177e4 | 223 | call->a_flags = RPC_TASK_ASYNC; |
92737230 | 224 | call->a_block = block; |
1da177e4 LT |
225 | |
226 | return block; | |
227 | ||
228 | failed_free: | |
229 | kfree(block); | |
230 | failed: | |
92737230 | 231 | nlm_release_call(call); |
1da177e4 LT |
232 | return NULL; |
233 | } | |
234 | ||
235 | /* | |
236 | * Delete a block. If the lock was cancelled or the grant callback | |
237 | * failed, unlock is set to 1. | |
238 | * It is the caller's responsibility to check whether the file | |
239 | * can be closed hereafter. | |
240 | */ | |
6849c0ca | 241 | static int nlmsvc_unlink_block(struct nlm_block *block) |
1da177e4 | 242 | { |
09c7938c | 243 | int status; |
6849c0ca | 244 | dprintk("lockd: unlinking block %p...\n", block); |
1da177e4 LT |
245 | |
246 | /* Remove block from list */ | |
92737230 | 247 | status = posix_unblock_lock(block->b_file->f_file, &block->b_call->a_args.lock.fl); |
1da177e4 | 248 | nlmsvc_remove_block(block); |
6849c0ca TM |
249 | return status; |
250 | } | |
1da177e4 | 251 | |
6849c0ca TM |
252 | static void nlmsvc_free_block(struct kref *kref) |
253 | { | |
254 | struct nlm_block *block = container_of(kref, struct nlm_block, b_count); | |
255 | struct nlm_file *file = block->b_file; | |
256 | struct nlm_block **bp; | |
257 | ||
258 | dprintk("lockd: freeing block %p...\n", block); | |
1da177e4 LT |
259 | |
260 | /* Remove block from file's list of blocks */ | |
261 | for (bp = &file->f_blocks; *bp; bp = &(*bp)->b_fnext) { | |
262 | if (*bp == block) { | |
263 | *bp = block->b_fnext; | |
264 | break; | |
265 | } | |
266 | } | |
267 | ||
92737230 TM |
268 | nlmsvc_freegrantargs(block->b_call); |
269 | nlm_release_call(block->b_call); | |
1da177e4 | 270 | kfree(block); |
6849c0ca TM |
271 | } |
272 | ||
273 | static void nlmsvc_release_block(struct nlm_block *block) | |
274 | { | |
275 | if (block != NULL) | |
276 | kref_put(&block->b_count, nlmsvc_free_block); | |
1da177e4 LT |
277 | } |
278 | ||
279 | /* | |
280 | * Loop over all blocks and perform the action specified. | |
281 | * (NLM_ACT_CHECK handled by nlmsvc_inspect_file). | |
282 | */ | |
283 | int | |
284 | nlmsvc_traverse_blocks(struct nlm_host *host, struct nlm_file *file, int action) | |
285 | { | |
286 | struct nlm_block *block, *next; | |
64a318ee | 287 | /* XXX: Will everything get cleaned up if we don't unlock here? */ |
1da177e4 LT |
288 | |
289 | down(&file->f_sema); | |
290 | for (block = file->f_blocks; block; block = next) { | |
291 | next = block->b_fnext; | |
292 | if (action == NLM_ACT_MARK) | |
293 | block->b_host->h_inuse = 1; | |
294 | else if (action == NLM_ACT_UNLOCK) { | |
295 | if (host == NULL || host == block->b_host) | |
6849c0ca | 296 | nlmsvc_unlink_block(block); |
1da177e4 LT |
297 | } |
298 | } | |
299 | up(&file->f_sema); | |
300 | return 0; | |
301 | } | |
302 | ||
5e1abf8c TM |
303 | /* |
304 | * Initialize arguments for GRANTED call. The nlm_rqst structure | |
305 | * has been cleared already. | |
306 | */ | |
307 | static int nlmsvc_setgrantargs(struct nlm_rqst *call, struct nlm_lock *lock) | |
308 | { | |
309 | locks_copy_lock(&call->a_args.lock.fl, &lock->fl); | |
310 | memcpy(&call->a_args.lock.fh, &lock->fh, sizeof(call->a_args.lock.fh)); | |
311 | call->a_args.lock.caller = system_utsname.nodename; | |
312 | call->a_args.lock.oh.len = lock->oh.len; | |
313 | ||
314 | /* set default data area */ | |
315 | call->a_args.lock.oh.data = call->a_owner; | |
316 | call->a_args.lock.svid = lock->fl.fl_pid; | |
317 | ||
318 | if (lock->oh.len > NLMCLNT_OHSIZE) { | |
319 | void *data = kmalloc(lock->oh.len, GFP_KERNEL); | |
92737230 | 320 | if (!data) |
5e1abf8c | 321 | return 0; |
5e1abf8c TM |
322 | call->a_args.lock.oh.data = (u8 *) data; |
323 | } | |
324 | ||
325 | memcpy(call->a_args.lock.oh.data, lock->oh.data, lock->oh.len); | |
326 | return 1; | |
327 | } | |
328 | ||
329 | static void nlmsvc_freegrantargs(struct nlm_rqst *call) | |
330 | { | |
92737230 | 331 | if (call->a_args.lock.oh.data != call->a_owner) |
5e1abf8c | 332 | kfree(call->a_args.lock.oh.data); |
5e1abf8c TM |
333 | } |
334 | ||
1da177e4 LT |
335 | /* |
336 | * Attempt to establish a lock, and if it can't be granted, block it | |
337 | * if required. | |
338 | */ | |
339 | u32 | |
340 | nlmsvc_lock(struct svc_rqst *rqstp, struct nlm_file *file, | |
341 | struct nlm_lock *lock, int wait, struct nlm_cookie *cookie) | |
342 | { | |
09c7938c | 343 | struct nlm_block *block, *newblock = NULL; |
1da177e4 | 344 | int error; |
15dadef9 | 345 | u32 ret; |
1da177e4 LT |
346 | |
347 | dprintk("lockd: nlmsvc_lock(%s/%ld, ty=%d, pi=%d, %Ld-%Ld, bl=%d)\n", | |
348 | file->f_file->f_dentry->d_inode->i_sb->s_id, | |
349 | file->f_file->f_dentry->d_inode->i_ino, | |
350 | lock->fl.fl_type, lock->fl.fl_pid, | |
351 | (long long)lock->fl.fl_start, | |
352 | (long long)lock->fl.fl_end, | |
353 | wait); | |
354 | ||
355 | ||
09c7938c | 356 | lock->fl.fl_flags &= ~FL_SLEEP; |
1da177e4 LT |
357 | again: |
358 | /* Lock file against concurrent access */ | |
359 | down(&file->f_sema); | |
09c7938c TM |
360 | /* Get existing block (in case client is busy-waiting) */ |
361 | block = nlmsvc_lookup_block(file, lock, 0); | |
362 | if (block == NULL) { | |
363 | if (newblock != NULL) | |
92737230 | 364 | lock = &newblock->b_call->a_args.lock; |
09c7938c | 365 | } else |
92737230 | 366 | lock = &block->b_call->a_args.lock; |
1da177e4 | 367 | |
a85f193e | 368 | error = posix_lock_file(file->f_file, &lock->fl); |
09c7938c | 369 | lock->fl.fl_flags &= ~FL_SLEEP; |
1da177e4 | 370 | |
a85f193e AA |
371 | dprintk("lockd: posix_lock_file returned %d\n", error); |
372 | ||
09c7938c | 373 | switch(error) { |
1da177e4 | 374 | case 0: |
15dadef9 AA |
375 | ret = nlm_granted; |
376 | goto out; | |
09c7938c TM |
377 | case -EAGAIN: |
378 | break; | |
379 | case -EDEADLK: | |
15dadef9 AA |
380 | ret = nlm_deadlock; |
381 | goto out; | |
1da177e4 | 382 | default: /* includes ENOLCK */ |
15dadef9 AA |
383 | ret = nlm_lck_denied_nolocks; |
384 | goto out; | |
1da177e4 LT |
385 | } |
386 | ||
09c7938c TM |
387 | ret = nlm_lck_denied; |
388 | if (!wait) | |
389 | goto out; | |
390 | ||
391 | ret = nlm_lck_blocked; | |
392 | if (block != NULL) | |
393 | goto out; | |
1da177e4 | 394 | |
1da177e4 LT |
395 | /* If we don't have a block, create and initialize it. Then |
396 | * retry because we may have slept in kmalloc. */ | |
397 | /* We have to release f_sema as nlmsvc_create_block may try to | |
398 | * to claim it while doing host garbage collection */ | |
09c7938c | 399 | if (newblock == NULL) { |
1da177e4 LT |
400 | up(&file->f_sema); |
401 | dprintk("lockd: blocking on this lock (allocating).\n"); | |
09c7938c | 402 | if (!(newblock = nlmsvc_create_block(rqstp, file, lock, cookie))) |
1da177e4 LT |
403 | return nlm_lck_denied_nolocks; |
404 | goto again; | |
405 | } | |
406 | ||
407 | /* Append to list of blocked */ | |
09c7938c | 408 | nlmsvc_insert_block(newblock, NLM_NEVER); |
15dadef9 | 409 | out: |
09c7938c | 410 | up(&file->f_sema); |
6849c0ca TM |
411 | nlmsvc_release_block(newblock); |
412 | nlmsvc_release_block(block); | |
15dadef9 AA |
413 | dprintk("lockd: nlmsvc_lock returned %u\n", ret); |
414 | return ret; | |
1da177e4 LT |
415 | } |
416 | ||
417 | /* | |
418 | * Test for presence of a conflicting lock. | |
419 | */ | |
420 | u32 | |
421 | nlmsvc_testlock(struct nlm_file *file, struct nlm_lock *lock, | |
422 | struct nlm_lock *conflock) | |
423 | { | |
1da177e4 LT |
424 | dprintk("lockd: nlmsvc_testlock(%s/%ld, ty=%d, %Ld-%Ld)\n", |
425 | file->f_file->f_dentry->d_inode->i_sb->s_id, | |
426 | file->f_file->f_dentry->d_inode->i_ino, | |
427 | lock->fl.fl_type, | |
428 | (long long)lock->fl.fl_start, | |
429 | (long long)lock->fl.fl_end); | |
430 | ||
8dc7c311 | 431 | if (posix_test_lock(file->f_file, &lock->fl, &conflock->fl)) { |
1da177e4 | 432 | dprintk("lockd: conflicting lock(ty=%d, %Ld-%Ld)\n", |
8dc7c311 AA |
433 | conflock->fl.fl_type, |
434 | (long long)conflock->fl.fl_start, | |
435 | (long long)conflock->fl.fl_end); | |
1da177e4 LT |
436 | conflock->caller = "somehost"; /* FIXME */ |
437 | conflock->oh.len = 0; /* don't return OH info */ | |
8dc7c311 | 438 | conflock->svid = conflock->fl.fl_pid; |
1da177e4 LT |
439 | return nlm_lck_denied; |
440 | } | |
441 | ||
442 | return nlm_granted; | |
443 | } | |
444 | ||
445 | /* | |
446 | * Remove a lock. | |
447 | * This implies a CANCEL call: We send a GRANT_MSG, the client replies | |
448 | * with a GRANT_RES call which gets lost, and calls UNLOCK immediately | |
449 | * afterwards. In this case the block will still be there, and hence | |
450 | * must be removed. | |
451 | */ | |
452 | u32 | |
453 | nlmsvc_unlock(struct nlm_file *file, struct nlm_lock *lock) | |
454 | { | |
455 | int error; | |
456 | ||
457 | dprintk("lockd: nlmsvc_unlock(%s/%ld, pi=%d, %Ld-%Ld)\n", | |
458 | file->f_file->f_dentry->d_inode->i_sb->s_id, | |
459 | file->f_file->f_dentry->d_inode->i_ino, | |
460 | lock->fl.fl_pid, | |
461 | (long long)lock->fl.fl_start, | |
462 | (long long)lock->fl.fl_end); | |
463 | ||
464 | /* First, cancel any lock that might be there */ | |
465 | nlmsvc_cancel_blocked(file, lock); | |
466 | ||
467 | lock->fl.fl_type = F_UNLCK; | |
468 | error = posix_lock_file(file->f_file, &lock->fl); | |
469 | ||
470 | return (error < 0)? nlm_lck_denied_nolocks : nlm_granted; | |
471 | } | |
472 | ||
473 | /* | |
474 | * Cancel a previously blocked request. | |
475 | * | |
476 | * A cancel request always overrides any grant that may currently | |
477 | * be in progress. | |
478 | * The calling procedure must check whether the file can be closed. | |
479 | */ | |
480 | u32 | |
481 | nlmsvc_cancel_blocked(struct nlm_file *file, struct nlm_lock *lock) | |
482 | { | |
483 | struct nlm_block *block; | |
64a318ee | 484 | int status = 0; |
1da177e4 LT |
485 | |
486 | dprintk("lockd: nlmsvc_cancel(%s/%ld, pi=%d, %Ld-%Ld)\n", | |
487 | file->f_file->f_dentry->d_inode->i_sb->s_id, | |
488 | file->f_file->f_dentry->d_inode->i_ino, | |
489 | lock->fl.fl_pid, | |
490 | (long long)lock->fl.fl_start, | |
491 | (long long)lock->fl.fl_end); | |
492 | ||
493 | down(&file->f_sema); | |
6849c0ca TM |
494 | if ((block = nlmsvc_lookup_block(file, lock, 1)) != NULL) { |
495 | status = nlmsvc_unlink_block(block); | |
496 | nlmsvc_release_block(block); | |
497 | } | |
1da177e4 | 498 | up(&file->f_sema); |
64a318ee | 499 | return status ? nlm_lck_denied : nlm_granted; |
1da177e4 LT |
500 | } |
501 | ||
502 | /* | |
503 | * Unblock a blocked lock request. This is a callback invoked from the | |
504 | * VFS layer when a lock on which we blocked is removed. | |
505 | * | |
506 | * This function doesn't grant the blocked lock instantly, but rather moves | |
507 | * the block to the head of nlm_blocked where it can be picked up by lockd. | |
508 | */ | |
509 | static void | |
510 | nlmsvc_notify_blocked(struct file_lock *fl) | |
511 | { | |
512 | struct nlm_block **bp, *block; | |
513 | ||
514 | dprintk("lockd: VFS unblock notification for block %p\n", fl); | |
515 | for (bp = &nlm_blocked; (block = *bp) != 0; bp = &block->b_next) { | |
92737230 | 516 | if (nlm_compare_locks(&block->b_call->a_args.lock.fl, fl)) { |
1da177e4 LT |
517 | nlmsvc_insert_block(block, 0); |
518 | svc_wake_up(block->b_daemon); | |
519 | return; | |
520 | } | |
521 | } | |
522 | ||
523 | printk(KERN_WARNING "lockd: notification for unknown block!\n"); | |
524 | } | |
525 | ||
526 | static int nlmsvc_same_owner(struct file_lock *fl1, struct file_lock *fl2) | |
527 | { | |
528 | return fl1->fl_owner == fl2->fl_owner && fl1->fl_pid == fl2->fl_pid; | |
529 | } | |
530 | ||
531 | struct lock_manager_operations nlmsvc_lock_operations = { | |
532 | .fl_compare_owner = nlmsvc_same_owner, | |
533 | .fl_notify = nlmsvc_notify_blocked, | |
534 | }; | |
535 | ||
536 | /* | |
537 | * Try to claim a lock that was previously blocked. | |
538 | * | |
539 | * Note that we use both the RPC_GRANTED_MSG call _and_ an async | |
540 | * RPC thread when notifying the client. This seems like overkill... | |
541 | * Here's why: | |
542 | * - we don't want to use a synchronous RPC thread, otherwise | |
543 | * we might find ourselves hanging on a dead portmapper. | |
544 | * - Some lockd implementations (e.g. HP) don't react to | |
545 | * RPC_GRANTED calls; they seem to insist on RPC_GRANTED_MSG calls. | |
546 | */ | |
547 | static void | |
548 | nlmsvc_grant_blocked(struct nlm_block *block) | |
549 | { | |
550 | struct nlm_file *file = block->b_file; | |
92737230 | 551 | struct nlm_lock *lock = &block->b_call->a_args.lock; |
1da177e4 LT |
552 | int error; |
553 | ||
554 | dprintk("lockd: grant blocked lock %p\n", block); | |
555 | ||
556 | /* First thing is lock the file */ | |
557 | down(&file->f_sema); | |
558 | ||
559 | /* Unlink block request from list */ | |
6849c0ca | 560 | nlmsvc_unlink_block(block); |
1da177e4 LT |
561 | |
562 | /* If b_granted is true this means we've been here before. | |
563 | * Just retry the grant callback, possibly refreshing the RPC | |
564 | * binding */ | |
565 | if (block->b_granted) { | |
566 | nlm_rebind_host(block->b_host); | |
567 | goto callback; | |
568 | } | |
569 | ||
570 | /* Try the lock operation again */ | |
09c7938c | 571 | lock->fl.fl_flags |= FL_SLEEP; |
5de0e502 | 572 | error = posix_lock_file(file->f_file, &lock->fl); |
09c7938c TM |
573 | lock->fl.fl_flags &= ~FL_SLEEP; |
574 | ||
5de0e502 AA |
575 | switch (error) { |
576 | case 0: | |
577 | break; | |
578 | case -EAGAIN: | |
1da177e4 LT |
579 | dprintk("lockd: lock still blocked\n"); |
580 | nlmsvc_insert_block(block, NLM_NEVER); | |
15dadef9 | 581 | goto out_unlock; |
5de0e502 | 582 | default: |
1da177e4 LT |
583 | printk(KERN_WARNING "lockd: unexpected error %d in %s!\n", |
584 | -error, __FUNCTION__); | |
585 | nlmsvc_insert_block(block, 10 * HZ); | |
15dadef9 | 586 | goto out_unlock; |
1da177e4 LT |
587 | } |
588 | ||
589 | callback: | |
590 | /* Lock was granted by VFS. */ | |
591 | dprintk("lockd: GRANTing blocked lock.\n"); | |
592 | block->b_granted = 1; | |
1da177e4 LT |
593 | |
594 | /* Schedule next grant callback in 30 seconds */ | |
595 | nlmsvc_insert_block(block, 30 * HZ); | |
596 | ||
597 | /* Call the client */ | |
6849c0ca | 598 | kref_get(&block->b_count); |
92737230 | 599 | if (nlm_async_call(block->b_call, NLMPROC_GRANTED_MSG, |
963d8fe5 | 600 | &nlmsvc_grant_ops) < 0) |
6849c0ca | 601 | nlmsvc_release_block(block); |
15dadef9 | 602 | out_unlock: |
1da177e4 LT |
603 | up(&file->f_sema); |
604 | } | |
605 | ||
606 | /* | |
607 | * This is the callback from the RPC layer when the NLM_GRANTED_MSG | |
608 | * RPC call has succeeded or timed out. | |
609 | * Like all RPC callbacks, it is invoked by the rpciod process, so it | |
610 | * better not sleep. Therefore, we put the blocked lock on the nlm_blocked | |
611 | * chain once more in order to have it removed by lockd itself (which can | |
612 | * then sleep on the file semaphore without disrupting e.g. the nfs client). | |
613 | */ | |
963d8fe5 | 614 | static void nlmsvc_grant_callback(struct rpc_task *task, void *data) |
1da177e4 | 615 | { |
963d8fe5 | 616 | struct nlm_rqst *call = data; |
92737230 | 617 | struct nlm_block *block = call->a_block; |
1da177e4 | 618 | unsigned long timeout; |
1da177e4 LT |
619 | |
620 | dprintk("lockd: GRANT_MSG RPC callback\n"); | |
1da177e4 LT |
621 | |
622 | /* Technically, we should down the file semaphore here. Since we | |
623 | * move the block towards the head of the queue only, no harm | |
624 | * can be done, though. */ | |
625 | if (task->tk_status < 0) { | |
626 | /* RPC error: Re-insert for retransmission */ | |
627 | timeout = 10 * HZ; | |
628 | } else if (block->b_done) { | |
629 | /* Block already removed, kill it for real */ | |
630 | timeout = 0; | |
631 | } else { | |
632 | /* Call was successful, now wait for client callback */ | |
633 | timeout = 60 * HZ; | |
634 | } | |
635 | nlmsvc_insert_block(block, timeout); | |
636 | svc_wake_up(block->b_daemon); | |
5e1abf8c TM |
637 | } |
638 | ||
639 | void nlmsvc_grant_release(void *data) | |
640 | { | |
6041b791 TM |
641 | struct nlm_rqst *call = data; |
642 | ||
643 | nlmsvc_release_block(call->a_block); | |
1da177e4 LT |
644 | } |
645 | ||
963d8fe5 TM |
646 | static const struct rpc_call_ops nlmsvc_grant_ops = { |
647 | .rpc_call_done = nlmsvc_grant_callback, | |
5e1abf8c | 648 | .rpc_release = nlmsvc_grant_release, |
963d8fe5 TM |
649 | }; |
650 | ||
1da177e4 LT |
651 | /* |
652 | * We received a GRANT_RES callback. Try to find the corresponding | |
653 | * block. | |
654 | */ | |
655 | void | |
656 | nlmsvc_grant_reply(struct svc_rqst *rqstp, struct nlm_cookie *cookie, u32 status) | |
657 | { | |
658 | struct nlm_block *block; | |
659 | struct nlm_file *file; | |
660 | ||
661 | dprintk("grant_reply: looking for cookie %x, host (%08x), s=%d \n", | |
662 | *(unsigned int *)(cookie->data), | |
663 | ntohl(rqstp->rq_addr.sin_addr.s_addr), status); | |
664 | if (!(block = nlmsvc_find_block(cookie, &rqstp->rq_addr))) | |
665 | return; | |
666 | file = block->b_file; | |
667 | ||
668 | file->f_count++; | |
669 | down(&file->f_sema); | |
f232142c | 670 | if (block) { |
1da177e4 LT |
671 | if (status == NLM_LCK_DENIED_GRACE_PERIOD) { |
672 | /* Try again in a couple of seconds */ | |
673 | nlmsvc_insert_block(block, 10 * HZ); | |
1da177e4 LT |
674 | } else { |
675 | /* Lock is now held by client, or has been rejected. | |
676 | * In both cases, the block should be removed. */ | |
6849c0ca | 677 | nlmsvc_unlink_block(block); |
1da177e4 LT |
678 | } |
679 | } | |
6849c0ca | 680 | up(&file->f_sema); |
1da177e4 | 681 | nlm_release_file(file); |
6849c0ca | 682 | nlmsvc_release_block(block); |
1da177e4 LT |
683 | } |
684 | ||
685 | /* | |
686 | * Retry all blocked locks that have been notified. This is where lockd | |
687 | * picks up locks that can be granted, or grant notifications that must | |
688 | * be retransmitted. | |
689 | */ | |
690 | unsigned long | |
691 | nlmsvc_retry_blocked(void) | |
692 | { | |
693 | struct nlm_block *block; | |
694 | ||
695 | dprintk("nlmsvc_retry_blocked(%p, when=%ld)\n", | |
696 | nlm_blocked, | |
697 | nlm_blocked? nlm_blocked->b_when : 0); | |
698 | while ((block = nlm_blocked) != 0) { | |
699 | if (block->b_when == NLM_NEVER) | |
700 | break; | |
701 | if (time_after(block->b_when,jiffies)) | |
702 | break; | |
703 | dprintk("nlmsvc_retry_blocked(%p, when=%ld, done=%d)\n", | |
704 | block, block->b_when, block->b_done); | |
6849c0ca | 705 | kref_get(&block->b_count); |
1da177e4 | 706 | if (block->b_done) |
6849c0ca | 707 | nlmsvc_unlink_block(block); |
1da177e4 LT |
708 | else |
709 | nlmsvc_grant_blocked(block); | |
6849c0ca | 710 | nlmsvc_release_block(block); |
1da177e4 LT |
711 | } |
712 | ||
713 | if ((block = nlm_blocked) && block->b_when != NLM_NEVER) | |
714 | return (block->b_when - jiffies); | |
715 | ||
716 | return MAX_SCHEDULE_TIMEOUT; | |
717 | } |