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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 | 42 | static void nlmsvc_insert_block(struct nlm_block *block, unsigned long); |
68a2d76c | 43 | static void 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 | */ | |
68a2d76c | 52 | static LIST_HEAD(nlm_blocked); |
1da177e4 LT |
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 | { | |
68a2d76c OK |
60 | struct nlm_block *b; |
61 | struct list_head *pos; | |
1da177e4 LT |
62 | |
63 | dprintk("lockd: nlmsvc_insert_block(%p, %ld)\n", block, when); | |
68a2d76c OK |
64 | if (list_empty(&block->b_list)) { |
65 | kref_get(&block->b_count); | |
66 | } else { | |
67 | list_del_init(&block->b_list); | |
68 | } | |
69 | ||
70 | pos = &nlm_blocked; | |
1da177e4 LT |
71 | if (when != NLM_NEVER) { |
72 | if ((when += jiffies) == NLM_NEVER) | |
73 | when ++; | |
68a2d76c OK |
74 | list_for_each(pos, &nlm_blocked) { |
75 | b = list_entry(pos, struct nlm_block, b_list); | |
76 | if (time_after(b->b_when,when) || b->b_when == NLM_NEVER) | |
77 | break; | |
78 | } | |
79 | /* On normal exit from the loop, pos == &nlm_blocked, | |
80 | * so we will be adding to the end of the list - good | |
81 | */ | |
82 | } | |
1da177e4 | 83 | |
68a2d76c | 84 | list_add_tail(&block->b_list, pos); |
1da177e4 | 85 | block->b_when = when; |
1da177e4 LT |
86 | } |
87 | ||
88 | /* | |
89 | * Remove a block from the global list | |
90 | */ | |
68a2d76c | 91 | static inline void |
1da177e4 LT |
92 | nlmsvc_remove_block(struct nlm_block *block) |
93 | { | |
68a2d76c OK |
94 | if (!list_empty(&block->b_list)) { |
95 | list_del_init(&block->b_list); | |
96 | nlmsvc_release_block(block); | |
1da177e4 | 97 | } |
1da177e4 LT |
98 | } |
99 | ||
100 | /* | |
d9f6eb75 | 101 | * Find a block for a given lock |
1da177e4 LT |
102 | */ |
103 | static struct nlm_block * | |
d9f6eb75 | 104 | nlmsvc_lookup_block(struct nlm_file *file, struct nlm_lock *lock) |
1da177e4 | 105 | { |
68a2d76c | 106 | struct nlm_block *block; |
1da177e4 LT |
107 | struct file_lock *fl; |
108 | ||
109 | dprintk("lockd: nlmsvc_lookup_block f=%p pd=%d %Ld-%Ld ty=%d\n", | |
110 | file, lock->fl.fl_pid, | |
111 | (long long)lock->fl.fl_start, | |
112 | (long long)lock->fl.fl_end, lock->fl.fl_type); | |
68a2d76c | 113 | list_for_each_entry(block, &nlm_blocked, b_list) { |
92737230 | 114 | fl = &block->b_call->a_args.lock.fl; |
1da177e4 LT |
115 | dprintk("lockd: check f=%p pd=%d %Ld-%Ld ty=%d cookie=%s\n", |
116 | block->b_file, fl->fl_pid, | |
117 | (long long)fl->fl_start, | |
118 | (long long)fl->fl_end, fl->fl_type, | |
92737230 | 119 | nlmdbg_cookie2a(&block->b_call->a_args.cookie)); |
1da177e4 | 120 | if (block->b_file == file && nlm_compare_locks(fl, &lock->fl)) { |
6849c0ca | 121 | kref_get(&block->b_count); |
1da177e4 LT |
122 | return block; |
123 | } | |
124 | } | |
125 | ||
126 | return NULL; | |
127 | } | |
128 | ||
129 | static inline int nlm_cookie_match(struct nlm_cookie *a, struct nlm_cookie *b) | |
130 | { | |
131 | if(a->len != b->len) | |
132 | return 0; | |
133 | if(memcmp(a->data,b->data,a->len)) | |
134 | return 0; | |
135 | return 1; | |
136 | } | |
137 | ||
138 | /* | |
139 | * Find a block with a given NLM cookie. | |
140 | */ | |
141 | static inline struct nlm_block * | |
142 | nlmsvc_find_block(struct nlm_cookie *cookie, struct sockaddr_in *sin) | |
143 | { | |
144 | struct nlm_block *block; | |
145 | ||
68a2d76c | 146 | list_for_each_entry(block, &nlm_blocked, b_list) { |
92737230 | 147 | if (nlm_cookie_match(&block->b_call->a_args.cookie,cookie) |
1da177e4 | 148 | && nlm_cmp_addr(sin, &block->b_host->h_addr)) |
68a2d76c | 149 | goto found; |
1da177e4 LT |
150 | } |
151 | ||
68a2d76c OK |
152 | return NULL; |
153 | ||
154 | found: | |
155 | kref_get(&block->b_count); | |
1da177e4 LT |
156 | return block; |
157 | } | |
158 | ||
159 | /* | |
160 | * Create a block and initialize it. | |
161 | * | |
162 | * Note: we explicitly set the cookie of the grant reply to that of | |
163 | * the blocked lock request. The spec explicitly mentions that the client | |
164 | * should _not_ rely on the callback containing the same cookie as the | |
165 | * request, but (as I found out later) that's because some implementations | |
166 | * do just this. Never mind the standards comittees, they support our | |
167 | * logging industries. | |
168 | */ | |
169 | static inline struct nlm_block * | |
170 | nlmsvc_create_block(struct svc_rqst *rqstp, struct nlm_file *file, | |
171 | struct nlm_lock *lock, struct nlm_cookie *cookie) | |
172 | { | |
173 | struct nlm_block *block; | |
174 | struct nlm_host *host; | |
92737230 | 175 | struct nlm_rqst *call = NULL; |
1da177e4 LT |
176 | |
177 | /* Create host handle for callback */ | |
db4e4c9a | 178 | host = nlmsvc_lookup_host(rqstp, lock->caller, lock->len); |
1da177e4 LT |
179 | if (host == NULL) |
180 | return NULL; | |
181 | ||
92737230 TM |
182 | call = nlm_alloc_call(host); |
183 | if (call == NULL) | |
184 | return NULL; | |
185 | ||
1da177e4 | 186 | /* Allocate memory for block, and initialize arguments */ |
92737230 TM |
187 | block = kzalloc(sizeof(*block), GFP_KERNEL); |
188 | if (block == NULL) | |
1da177e4 | 189 | goto failed; |
6849c0ca | 190 | kref_init(&block->b_count); |
68a2d76c OK |
191 | INIT_LIST_HEAD(&block->b_list); |
192 | INIT_LIST_HEAD(&block->b_flist); | |
1da177e4 | 193 | |
92737230 | 194 | if (!nlmsvc_setgrantargs(call, lock)) |
1da177e4 LT |
195 | goto failed_free; |
196 | ||
197 | /* Set notifier function for VFS, and init args */ | |
92737230 TM |
198 | call->a_args.lock.fl.fl_flags |= FL_SLEEP; |
199 | call->a_args.lock.fl.fl_lmops = &nlmsvc_lock_operations; | |
200 | call->a_args.cookie = *cookie; /* see above */ | |
1da177e4 LT |
201 | |
202 | dprintk("lockd: created block %p...\n", block); | |
203 | ||
204 | /* Create and initialize the block */ | |
205 | block->b_daemon = rqstp->rq_server; | |
206 | block->b_host = host; | |
207 | block->b_file = file; | |
d9f6eb75 | 208 | file->f_count++; |
1da177e4 LT |
209 | |
210 | /* Add to file's list of blocks */ | |
68a2d76c | 211 | list_add(&block->b_flist, &file->f_blocks); |
1da177e4 LT |
212 | |
213 | /* Set up RPC arguments for callback */ | |
92737230 | 214 | block->b_call = call; |
1da177e4 | 215 | call->a_flags = RPC_TASK_ASYNC; |
92737230 | 216 | call->a_block = block; |
1da177e4 LT |
217 | |
218 | return block; | |
219 | ||
220 | failed_free: | |
221 | kfree(block); | |
222 | failed: | |
92737230 | 223 | nlm_release_call(call); |
1da177e4 LT |
224 | return NULL; |
225 | } | |
226 | ||
227 | /* | |
228 | * Delete a block. If the lock was cancelled or the grant callback | |
229 | * failed, unlock is set to 1. | |
230 | * It is the caller's responsibility to check whether the file | |
231 | * can be closed hereafter. | |
232 | */ | |
6849c0ca | 233 | static int nlmsvc_unlink_block(struct nlm_block *block) |
1da177e4 | 234 | { |
09c7938c | 235 | int status; |
6849c0ca | 236 | dprintk("lockd: unlinking block %p...\n", block); |
1da177e4 LT |
237 | |
238 | /* Remove block from list */ | |
92737230 | 239 | status = posix_unblock_lock(block->b_file->f_file, &block->b_call->a_args.lock.fl); |
1da177e4 | 240 | nlmsvc_remove_block(block); |
6849c0ca TM |
241 | return status; |
242 | } | |
1da177e4 | 243 | |
6849c0ca TM |
244 | static void nlmsvc_free_block(struct kref *kref) |
245 | { | |
246 | struct nlm_block *block = container_of(kref, struct nlm_block, b_count); | |
247 | struct nlm_file *file = block->b_file; | |
6849c0ca TM |
248 | |
249 | dprintk("lockd: freeing block %p...\n", block); | |
1da177e4 LT |
250 | |
251 | /* Remove block from file's list of blocks */ | |
68a2d76c OK |
252 | down(&file->f_sema); |
253 | list_del_init(&block->b_flist); | |
d9f6eb75 | 254 | up(&file->f_sema); |
1da177e4 | 255 | |
92737230 TM |
256 | nlmsvc_freegrantargs(block->b_call); |
257 | nlm_release_call(block->b_call); | |
d9f6eb75 | 258 | nlm_release_file(block->b_file); |
1da177e4 | 259 | kfree(block); |
6849c0ca TM |
260 | } |
261 | ||
262 | static void nlmsvc_release_block(struct nlm_block *block) | |
263 | { | |
264 | if (block != NULL) | |
265 | kref_put(&block->b_count, nlmsvc_free_block); | |
1da177e4 LT |
266 | } |
267 | ||
f2af793d OK |
268 | /* |
269 | * Loop over all blocks and delete blocks held by | |
270 | * a matching host. | |
271 | */ | |
272 | void nlmsvc_traverse_blocks(struct nlm_host *host, | |
273 | struct nlm_file *file, | |
274 | nlm_host_match_fn_t match) | |
d9f6eb75 | 275 | { |
68a2d76c | 276 | struct nlm_block *block, *next; |
d9f6eb75 TM |
277 | |
278 | restart: | |
279 | down(&file->f_sema); | |
68a2d76c | 280 | list_for_each_entry_safe(block, next, &file->f_blocks, b_flist) { |
f2af793d | 281 | if (!match(block->b_host, host)) |
d9f6eb75 | 282 | continue; |
68a2d76c OK |
283 | /* Do not destroy blocks that are not on |
284 | * the global retry list - why? */ | |
285 | if (list_empty(&block->b_list)) | |
d9f6eb75 TM |
286 | continue; |
287 | kref_get(&block->b_count); | |
288 | up(&file->f_sema); | |
289 | nlmsvc_unlink_block(block); | |
290 | nlmsvc_release_block(block); | |
291 | goto restart; | |
292 | } | |
293 | up(&file->f_sema); | |
294 | } | |
295 | ||
5e1abf8c TM |
296 | /* |
297 | * Initialize arguments for GRANTED call. The nlm_rqst structure | |
298 | * has been cleared already. | |
299 | */ | |
300 | static int nlmsvc_setgrantargs(struct nlm_rqst *call, struct nlm_lock *lock) | |
301 | { | |
302 | locks_copy_lock(&call->a_args.lock.fl, &lock->fl); | |
303 | memcpy(&call->a_args.lock.fh, &lock->fh, sizeof(call->a_args.lock.fh)); | |
e9ff3990 | 304 | call->a_args.lock.caller = utsname()->nodename; |
5e1abf8c TM |
305 | call->a_args.lock.oh.len = lock->oh.len; |
306 | ||
307 | /* set default data area */ | |
308 | call->a_args.lock.oh.data = call->a_owner; | |
309 | call->a_args.lock.svid = lock->fl.fl_pid; | |
310 | ||
311 | if (lock->oh.len > NLMCLNT_OHSIZE) { | |
312 | void *data = kmalloc(lock->oh.len, GFP_KERNEL); | |
92737230 | 313 | if (!data) |
5e1abf8c | 314 | return 0; |
5e1abf8c TM |
315 | call->a_args.lock.oh.data = (u8 *) data; |
316 | } | |
317 | ||
318 | memcpy(call->a_args.lock.oh.data, lock->oh.data, lock->oh.len); | |
319 | return 1; | |
320 | } | |
321 | ||
322 | static void nlmsvc_freegrantargs(struct nlm_rqst *call) | |
323 | { | |
92737230 | 324 | if (call->a_args.lock.oh.data != call->a_owner) |
5e1abf8c | 325 | kfree(call->a_args.lock.oh.data); |
5e1abf8c TM |
326 | } |
327 | ||
1da177e4 LT |
328 | /* |
329 | * Attempt to establish a lock, and if it can't be granted, block it | |
330 | * if required. | |
331 | */ | |
332 | u32 | |
333 | nlmsvc_lock(struct svc_rqst *rqstp, struct nlm_file *file, | |
334 | struct nlm_lock *lock, int wait, struct nlm_cookie *cookie) | |
335 | { | |
09c7938c | 336 | struct nlm_block *block, *newblock = NULL; |
1da177e4 | 337 | int error; |
15dadef9 | 338 | u32 ret; |
1da177e4 LT |
339 | |
340 | dprintk("lockd: nlmsvc_lock(%s/%ld, ty=%d, pi=%d, %Ld-%Ld, bl=%d)\n", | |
341 | file->f_file->f_dentry->d_inode->i_sb->s_id, | |
342 | file->f_file->f_dentry->d_inode->i_ino, | |
343 | lock->fl.fl_type, lock->fl.fl_pid, | |
344 | (long long)lock->fl.fl_start, | |
345 | (long long)lock->fl.fl_end, | |
346 | wait); | |
347 | ||
348 | ||
09c7938c | 349 | lock->fl.fl_flags &= ~FL_SLEEP; |
1da177e4 LT |
350 | again: |
351 | /* Lock file against concurrent access */ | |
352 | down(&file->f_sema); | |
09c7938c | 353 | /* Get existing block (in case client is busy-waiting) */ |
d9f6eb75 | 354 | block = nlmsvc_lookup_block(file, lock); |
09c7938c TM |
355 | if (block == NULL) { |
356 | if (newblock != NULL) | |
92737230 | 357 | lock = &newblock->b_call->a_args.lock; |
09c7938c | 358 | } else |
92737230 | 359 | lock = &block->b_call->a_args.lock; |
1da177e4 | 360 | |
a85f193e | 361 | error = posix_lock_file(file->f_file, &lock->fl); |
09c7938c | 362 | lock->fl.fl_flags &= ~FL_SLEEP; |
1da177e4 | 363 | |
a85f193e AA |
364 | dprintk("lockd: posix_lock_file returned %d\n", error); |
365 | ||
09c7938c | 366 | switch(error) { |
1da177e4 | 367 | case 0: |
15dadef9 AA |
368 | ret = nlm_granted; |
369 | goto out; | |
09c7938c TM |
370 | case -EAGAIN: |
371 | break; | |
372 | case -EDEADLK: | |
15dadef9 AA |
373 | ret = nlm_deadlock; |
374 | goto out; | |
1da177e4 | 375 | default: /* includes ENOLCK */ |
15dadef9 AA |
376 | ret = nlm_lck_denied_nolocks; |
377 | goto out; | |
1da177e4 LT |
378 | } |
379 | ||
09c7938c TM |
380 | ret = nlm_lck_denied; |
381 | if (!wait) | |
382 | goto out; | |
383 | ||
384 | ret = nlm_lck_blocked; | |
385 | if (block != NULL) | |
386 | goto out; | |
1da177e4 | 387 | |
1da177e4 LT |
388 | /* If we don't have a block, create and initialize it. Then |
389 | * retry because we may have slept in kmalloc. */ | |
390 | /* We have to release f_sema as nlmsvc_create_block may try to | |
391 | * to claim it while doing host garbage collection */ | |
09c7938c | 392 | if (newblock == NULL) { |
1da177e4 LT |
393 | up(&file->f_sema); |
394 | dprintk("lockd: blocking on this lock (allocating).\n"); | |
09c7938c | 395 | if (!(newblock = nlmsvc_create_block(rqstp, file, lock, cookie))) |
1da177e4 LT |
396 | return nlm_lck_denied_nolocks; |
397 | goto again; | |
398 | } | |
399 | ||
400 | /* Append to list of blocked */ | |
09c7938c | 401 | nlmsvc_insert_block(newblock, NLM_NEVER); |
15dadef9 | 402 | out: |
09c7938c | 403 | up(&file->f_sema); |
6849c0ca TM |
404 | nlmsvc_release_block(newblock); |
405 | nlmsvc_release_block(block); | |
15dadef9 AA |
406 | dprintk("lockd: nlmsvc_lock returned %u\n", ret); |
407 | return ret; | |
1da177e4 LT |
408 | } |
409 | ||
410 | /* | |
411 | * Test for presence of a conflicting lock. | |
412 | */ | |
413 | u32 | |
414 | nlmsvc_testlock(struct nlm_file *file, struct nlm_lock *lock, | |
415 | struct nlm_lock *conflock) | |
416 | { | |
1da177e4 LT |
417 | dprintk("lockd: nlmsvc_testlock(%s/%ld, ty=%d, %Ld-%Ld)\n", |
418 | file->f_file->f_dentry->d_inode->i_sb->s_id, | |
419 | file->f_file->f_dentry->d_inode->i_ino, | |
420 | lock->fl.fl_type, | |
421 | (long long)lock->fl.fl_start, | |
422 | (long long)lock->fl.fl_end); | |
423 | ||
8dc7c311 | 424 | if (posix_test_lock(file->f_file, &lock->fl, &conflock->fl)) { |
1da177e4 | 425 | dprintk("lockd: conflicting lock(ty=%d, %Ld-%Ld)\n", |
8dc7c311 AA |
426 | conflock->fl.fl_type, |
427 | (long long)conflock->fl.fl_start, | |
428 | (long long)conflock->fl.fl_end); | |
1da177e4 | 429 | conflock->caller = "somehost"; /* FIXME */ |
db4e4c9a | 430 | conflock->len = strlen(conflock->caller); |
1da177e4 | 431 | conflock->oh.len = 0; /* don't return OH info */ |
8dc7c311 | 432 | conflock->svid = conflock->fl.fl_pid; |
1da177e4 LT |
433 | return nlm_lck_denied; |
434 | } | |
435 | ||
436 | return nlm_granted; | |
437 | } | |
438 | ||
439 | /* | |
440 | * Remove a lock. | |
441 | * This implies a CANCEL call: We send a GRANT_MSG, the client replies | |
442 | * with a GRANT_RES call which gets lost, and calls UNLOCK immediately | |
443 | * afterwards. In this case the block will still be there, and hence | |
444 | * must be removed. | |
445 | */ | |
446 | u32 | |
447 | nlmsvc_unlock(struct nlm_file *file, struct nlm_lock *lock) | |
448 | { | |
449 | int error; | |
450 | ||
451 | dprintk("lockd: nlmsvc_unlock(%s/%ld, pi=%d, %Ld-%Ld)\n", | |
452 | file->f_file->f_dentry->d_inode->i_sb->s_id, | |
453 | file->f_file->f_dentry->d_inode->i_ino, | |
454 | lock->fl.fl_pid, | |
455 | (long long)lock->fl.fl_start, | |
456 | (long long)lock->fl.fl_end); | |
457 | ||
458 | /* First, cancel any lock that might be there */ | |
459 | nlmsvc_cancel_blocked(file, lock); | |
460 | ||
461 | lock->fl.fl_type = F_UNLCK; | |
462 | error = posix_lock_file(file->f_file, &lock->fl); | |
463 | ||
464 | return (error < 0)? nlm_lck_denied_nolocks : nlm_granted; | |
465 | } | |
466 | ||
467 | /* | |
468 | * Cancel a previously blocked request. | |
469 | * | |
470 | * A cancel request always overrides any grant that may currently | |
471 | * be in progress. | |
472 | * The calling procedure must check whether the file can be closed. | |
473 | */ | |
474 | u32 | |
475 | nlmsvc_cancel_blocked(struct nlm_file *file, struct nlm_lock *lock) | |
476 | { | |
477 | struct nlm_block *block; | |
64a318ee | 478 | int status = 0; |
1da177e4 LT |
479 | |
480 | dprintk("lockd: nlmsvc_cancel(%s/%ld, pi=%d, %Ld-%Ld)\n", | |
481 | file->f_file->f_dentry->d_inode->i_sb->s_id, | |
482 | file->f_file->f_dentry->d_inode->i_ino, | |
483 | lock->fl.fl_pid, | |
484 | (long long)lock->fl.fl_start, | |
485 | (long long)lock->fl.fl_end); | |
486 | ||
487 | down(&file->f_sema); | |
d9f6eb75 TM |
488 | block = nlmsvc_lookup_block(file, lock); |
489 | up(&file->f_sema); | |
490 | if (block != NULL) { | |
6849c0ca TM |
491 | status = nlmsvc_unlink_block(block); |
492 | nlmsvc_release_block(block); | |
493 | } | |
64a318ee | 494 | return status ? nlm_lck_denied : nlm_granted; |
1da177e4 LT |
495 | } |
496 | ||
497 | /* | |
498 | * Unblock a blocked lock request. This is a callback invoked from the | |
499 | * VFS layer when a lock on which we blocked is removed. | |
500 | * | |
501 | * This function doesn't grant the blocked lock instantly, but rather moves | |
502 | * the block to the head of nlm_blocked where it can be picked up by lockd. | |
503 | */ | |
504 | static void | |
505 | nlmsvc_notify_blocked(struct file_lock *fl) | |
506 | { | |
68a2d76c | 507 | struct nlm_block *block; |
1da177e4 LT |
508 | |
509 | dprintk("lockd: VFS unblock notification for block %p\n", fl); | |
68a2d76c | 510 | list_for_each_entry(block, &nlm_blocked, b_list) { |
92737230 | 511 | if (nlm_compare_locks(&block->b_call->a_args.lock.fl, fl)) { |
1da177e4 LT |
512 | nlmsvc_insert_block(block, 0); |
513 | svc_wake_up(block->b_daemon); | |
514 | return; | |
515 | } | |
516 | } | |
517 | ||
518 | printk(KERN_WARNING "lockd: notification for unknown block!\n"); | |
519 | } | |
520 | ||
521 | static int nlmsvc_same_owner(struct file_lock *fl1, struct file_lock *fl2) | |
522 | { | |
523 | return fl1->fl_owner == fl2->fl_owner && fl1->fl_pid == fl2->fl_pid; | |
524 | } | |
525 | ||
526 | struct lock_manager_operations nlmsvc_lock_operations = { | |
527 | .fl_compare_owner = nlmsvc_same_owner, | |
528 | .fl_notify = nlmsvc_notify_blocked, | |
529 | }; | |
530 | ||
531 | /* | |
532 | * Try to claim a lock that was previously blocked. | |
533 | * | |
534 | * Note that we use both the RPC_GRANTED_MSG call _and_ an async | |
535 | * RPC thread when notifying the client. This seems like overkill... | |
536 | * Here's why: | |
537 | * - we don't want to use a synchronous RPC thread, otherwise | |
538 | * we might find ourselves hanging on a dead portmapper. | |
539 | * - Some lockd implementations (e.g. HP) don't react to | |
540 | * RPC_GRANTED calls; they seem to insist on RPC_GRANTED_MSG calls. | |
541 | */ | |
542 | static void | |
543 | nlmsvc_grant_blocked(struct nlm_block *block) | |
544 | { | |
545 | struct nlm_file *file = block->b_file; | |
92737230 | 546 | struct nlm_lock *lock = &block->b_call->a_args.lock; |
1da177e4 LT |
547 | int error; |
548 | ||
549 | dprintk("lockd: grant blocked lock %p\n", block); | |
550 | ||
1da177e4 | 551 | /* Unlink block request from list */ |
6849c0ca | 552 | nlmsvc_unlink_block(block); |
1da177e4 LT |
553 | |
554 | /* If b_granted is true this means we've been here before. | |
555 | * Just retry the grant callback, possibly refreshing the RPC | |
556 | * binding */ | |
557 | if (block->b_granted) { | |
558 | nlm_rebind_host(block->b_host); | |
559 | goto callback; | |
560 | } | |
561 | ||
562 | /* Try the lock operation again */ | |
09c7938c | 563 | lock->fl.fl_flags |= FL_SLEEP; |
5de0e502 | 564 | error = posix_lock_file(file->f_file, &lock->fl); |
09c7938c TM |
565 | lock->fl.fl_flags &= ~FL_SLEEP; |
566 | ||
5de0e502 AA |
567 | switch (error) { |
568 | case 0: | |
569 | break; | |
570 | case -EAGAIN: | |
1da177e4 LT |
571 | dprintk("lockd: lock still blocked\n"); |
572 | nlmsvc_insert_block(block, NLM_NEVER); | |
d9f6eb75 | 573 | return; |
5de0e502 | 574 | default: |
1da177e4 LT |
575 | printk(KERN_WARNING "lockd: unexpected error %d in %s!\n", |
576 | -error, __FUNCTION__); | |
577 | nlmsvc_insert_block(block, 10 * HZ); | |
d9f6eb75 | 578 | return; |
1da177e4 LT |
579 | } |
580 | ||
581 | callback: | |
582 | /* Lock was granted by VFS. */ | |
583 | dprintk("lockd: GRANTing blocked lock.\n"); | |
584 | block->b_granted = 1; | |
1da177e4 LT |
585 | |
586 | /* Schedule next grant callback in 30 seconds */ | |
587 | nlmsvc_insert_block(block, 30 * HZ); | |
588 | ||
589 | /* Call the client */ | |
6849c0ca | 590 | kref_get(&block->b_count); |
92737230 | 591 | if (nlm_async_call(block->b_call, NLMPROC_GRANTED_MSG, |
963d8fe5 | 592 | &nlmsvc_grant_ops) < 0) |
6849c0ca | 593 | nlmsvc_release_block(block); |
1da177e4 LT |
594 | } |
595 | ||
596 | /* | |
597 | * This is the callback from the RPC layer when the NLM_GRANTED_MSG | |
598 | * RPC call has succeeded or timed out. | |
599 | * Like all RPC callbacks, it is invoked by the rpciod process, so it | |
600 | * better not sleep. Therefore, we put the blocked lock on the nlm_blocked | |
601 | * chain once more in order to have it removed by lockd itself (which can | |
602 | * then sleep on the file semaphore without disrupting e.g. the nfs client). | |
603 | */ | |
963d8fe5 | 604 | static void nlmsvc_grant_callback(struct rpc_task *task, void *data) |
1da177e4 | 605 | { |
963d8fe5 | 606 | struct nlm_rqst *call = data; |
92737230 | 607 | struct nlm_block *block = call->a_block; |
1da177e4 | 608 | unsigned long timeout; |
1da177e4 LT |
609 | |
610 | dprintk("lockd: GRANT_MSG RPC callback\n"); | |
1da177e4 LT |
611 | |
612 | /* Technically, we should down the file semaphore here. Since we | |
613 | * move the block towards the head of the queue only, no harm | |
614 | * can be done, though. */ | |
615 | if (task->tk_status < 0) { | |
616 | /* RPC error: Re-insert for retransmission */ | |
617 | timeout = 10 * HZ; | |
1da177e4 LT |
618 | } else { |
619 | /* Call was successful, now wait for client callback */ | |
620 | timeout = 60 * HZ; | |
621 | } | |
622 | nlmsvc_insert_block(block, timeout); | |
623 | svc_wake_up(block->b_daemon); | |
5e1abf8c TM |
624 | } |
625 | ||
ec535ce1 | 626 | static void nlmsvc_grant_release(void *data) |
5e1abf8c | 627 | { |
6041b791 TM |
628 | struct nlm_rqst *call = data; |
629 | ||
630 | nlmsvc_release_block(call->a_block); | |
1da177e4 LT |
631 | } |
632 | ||
963d8fe5 TM |
633 | static const struct rpc_call_ops nlmsvc_grant_ops = { |
634 | .rpc_call_done = nlmsvc_grant_callback, | |
5e1abf8c | 635 | .rpc_release = nlmsvc_grant_release, |
963d8fe5 TM |
636 | }; |
637 | ||
1da177e4 LT |
638 | /* |
639 | * We received a GRANT_RES callback. Try to find the corresponding | |
640 | * block. | |
641 | */ | |
642 | void | |
643 | nlmsvc_grant_reply(struct svc_rqst *rqstp, struct nlm_cookie *cookie, u32 status) | |
644 | { | |
645 | struct nlm_block *block; | |
646 | struct nlm_file *file; | |
647 | ||
648 | dprintk("grant_reply: looking for cookie %x, host (%08x), s=%d \n", | |
649 | *(unsigned int *)(cookie->data), | |
650 | ntohl(rqstp->rq_addr.sin_addr.s_addr), status); | |
651 | if (!(block = nlmsvc_find_block(cookie, &rqstp->rq_addr))) | |
652 | return; | |
653 | file = block->b_file; | |
654 | ||
f232142c | 655 | if (block) { |
1da177e4 LT |
656 | if (status == NLM_LCK_DENIED_GRACE_PERIOD) { |
657 | /* Try again in a couple of seconds */ | |
658 | nlmsvc_insert_block(block, 10 * HZ); | |
1da177e4 LT |
659 | } else { |
660 | /* Lock is now held by client, or has been rejected. | |
661 | * In both cases, the block should be removed. */ | |
6849c0ca | 662 | nlmsvc_unlink_block(block); |
1da177e4 LT |
663 | } |
664 | } | |
6849c0ca | 665 | nlmsvc_release_block(block); |
1da177e4 LT |
666 | } |
667 | ||
668 | /* | |
669 | * Retry all blocked locks that have been notified. This is where lockd | |
670 | * picks up locks that can be granted, or grant notifications that must | |
671 | * be retransmitted. | |
672 | */ | |
673 | unsigned long | |
674 | nlmsvc_retry_blocked(void) | |
675 | { | |
68a2d76c OK |
676 | unsigned long timeout = MAX_SCHEDULE_TIMEOUT; |
677 | struct nlm_block *block; | |
678 | ||
679 | while (!list_empty(&nlm_blocked)) { | |
680 | block = list_entry(nlm_blocked.next, struct nlm_block, b_list); | |
1da177e4 | 681 | |
1da177e4 LT |
682 | if (block->b_when == NLM_NEVER) |
683 | break; | |
68a2d76c OK |
684 | if (time_after(block->b_when,jiffies)) { |
685 | timeout = block->b_when - jiffies; | |
1da177e4 | 686 | break; |
68a2d76c OK |
687 | } |
688 | ||
f3d43c76 BF |
689 | dprintk("nlmsvc_retry_blocked(%p, when=%ld)\n", |
690 | block, block->b_when); | |
6849c0ca | 691 | kref_get(&block->b_count); |
f3d43c76 | 692 | nlmsvc_grant_blocked(block); |
6849c0ca | 693 | nlmsvc_release_block(block); |
1da177e4 LT |
694 | } |
695 | ||
68a2d76c | 696 | return timeout; |
1da177e4 | 697 | } |