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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> | |
d751a7cd | 32 | #include <linux/kthread.h> |
1da177e4 LT |
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 | 43 | static void nlmsvc_insert_block(struct nlm_block *block, unsigned long); |
68a2d76c | 44 | static void 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 | */ | |
68a2d76c | 53 | static LIST_HEAD(nlm_blocked); |
1da177e4 LT |
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 | { | |
68a2d76c OK |
61 | struct nlm_block *b; |
62 | struct list_head *pos; | |
1da177e4 LT |
63 | |
64 | dprintk("lockd: nlmsvc_insert_block(%p, %ld)\n", block, when); | |
68a2d76c OK |
65 | if (list_empty(&block->b_list)) { |
66 | kref_get(&block->b_count); | |
67 | } else { | |
68 | list_del_init(&block->b_list); | |
69 | } | |
70 | ||
71 | pos = &nlm_blocked; | |
1da177e4 LT |
72 | if (when != NLM_NEVER) { |
73 | if ((when += jiffies) == NLM_NEVER) | |
74 | when ++; | |
68a2d76c OK |
75 | list_for_each(pos, &nlm_blocked) { |
76 | b = list_entry(pos, struct nlm_block, b_list); | |
77 | if (time_after(b->b_when,when) || b->b_when == NLM_NEVER) | |
78 | break; | |
79 | } | |
80 | /* On normal exit from the loop, pos == &nlm_blocked, | |
81 | * so we will be adding to the end of the list - good | |
82 | */ | |
83 | } | |
1da177e4 | 84 | |
68a2d76c | 85 | list_add_tail(&block->b_list, pos); |
1da177e4 | 86 | block->b_when = when; |
1da177e4 LT |
87 | } |
88 | ||
89 | /* | |
90 | * Remove a block from the global list | |
91 | */ | |
68a2d76c | 92 | static inline void |
1da177e4 LT |
93 | nlmsvc_remove_block(struct nlm_block *block) |
94 | { | |
68a2d76c OK |
95 | if (!list_empty(&block->b_list)) { |
96 | list_del_init(&block->b_list); | |
97 | nlmsvc_release_block(block); | |
1da177e4 | 98 | } |
1da177e4 LT |
99 | } |
100 | ||
101 | /* | |
d9f6eb75 | 102 | * Find a block for a given lock |
1da177e4 LT |
103 | */ |
104 | static struct nlm_block * | |
d9f6eb75 | 105 | nlmsvc_lookup_block(struct nlm_file *file, struct nlm_lock *lock) |
1da177e4 | 106 | { |
68a2d76c | 107 | struct nlm_block *block; |
1da177e4 LT |
108 | struct file_lock *fl; |
109 | ||
110 | dprintk("lockd: nlmsvc_lookup_block f=%p pd=%d %Ld-%Ld ty=%d\n", | |
111 | file, lock->fl.fl_pid, | |
112 | (long long)lock->fl.fl_start, | |
113 | (long long)lock->fl.fl_end, lock->fl.fl_type); | |
68a2d76c | 114 | list_for_each_entry(block, &nlm_blocked, b_list) { |
92737230 | 115 | fl = &block->b_call->a_args.lock.fl; |
1da177e4 LT |
116 | dprintk("lockd: check f=%p pd=%d %Ld-%Ld ty=%d cookie=%s\n", |
117 | block->b_file, fl->fl_pid, | |
118 | (long long)fl->fl_start, | |
119 | (long long)fl->fl_end, fl->fl_type, | |
92737230 | 120 | nlmdbg_cookie2a(&block->b_call->a_args.cookie)); |
1da177e4 | 121 | if (block->b_file == file && nlm_compare_locks(fl, &lock->fl)) { |
6849c0ca | 122 | kref_get(&block->b_count); |
1da177e4 LT |
123 | return block; |
124 | } | |
125 | } | |
126 | ||
127 | return NULL; | |
128 | } | |
129 | ||
130 | static inline int nlm_cookie_match(struct nlm_cookie *a, struct nlm_cookie *b) | |
131 | { | |
6d7bbbba | 132 | if (a->len != b->len) |
1da177e4 | 133 | return 0; |
6d7bbbba | 134 | if (memcmp(a->data, b->data, a->len)) |
1da177e4 LT |
135 | return 0; |
136 | return 1; | |
137 | } | |
138 | ||
139 | /* | |
140 | * Find a block with a given NLM cookie. | |
141 | */ | |
142 | static inline struct nlm_block * | |
39be4502 | 143 | nlmsvc_find_block(struct nlm_cookie *cookie) |
1da177e4 LT |
144 | { |
145 | struct nlm_block *block; | |
146 | ||
68a2d76c | 147 | list_for_each_entry(block, &nlm_blocked, b_list) { |
39be4502 | 148 | if (nlm_cookie_match(&block->b_call->a_args.cookie,cookie)) |
68a2d76c | 149 | goto found; |
1da177e4 LT |
150 | } |
151 | ||
68a2d76c OK |
152 | return NULL; |
153 | ||
154 | found: | |
39be4502 | 155 | dprintk("nlmsvc_find_block(%s): block=%p\n", nlmdbg_cookie2a(cookie), block); |
68a2d76c | 156 | kref_get(&block->b_count); |
1da177e4 LT |
157 | return block; |
158 | } | |
159 | ||
160 | /* | |
161 | * Create a block and initialize it. | |
162 | * | |
163 | * Note: we explicitly set the cookie of the grant reply to that of | |
164 | * the blocked lock request. The spec explicitly mentions that the client | |
165 | * should _not_ rely on the callback containing the same cookie as the | |
166 | * request, but (as I found out later) that's because some implementations | |
167 | * do just this. Never mind the standards comittees, they support our | |
168 | * logging industries. | |
39be4502 OK |
169 | * |
170 | * 10 years later: I hope we can safely ignore these old and broken | |
171 | * clients by now. Let's fix this so we can uniquely identify an incoming | |
172 | * GRANTED_RES message by cookie, without having to rely on the client's IP | |
173 | * address. --okir | |
1da177e4 | 174 | */ |
255129d1 TM |
175 | static struct nlm_block * |
176 | nlmsvc_create_block(struct svc_rqst *rqstp, struct nlm_host *host, | |
177 | struct nlm_file *file, struct nlm_lock *lock, | |
178 | struct nlm_cookie *cookie) | |
1da177e4 LT |
179 | { |
180 | struct nlm_block *block; | |
92737230 | 181 | struct nlm_rqst *call = NULL; |
1da177e4 | 182 | |
92737230 TM |
183 | call = nlm_alloc_call(host); |
184 | if (call == NULL) | |
185 | return NULL; | |
186 | ||
1da177e4 | 187 | /* Allocate memory for block, and initialize arguments */ |
92737230 TM |
188 | block = kzalloc(sizeof(*block), GFP_KERNEL); |
189 | if (block == NULL) | |
1da177e4 | 190 | goto failed; |
6849c0ca | 191 | kref_init(&block->b_count); |
68a2d76c OK |
192 | INIT_LIST_HEAD(&block->b_list); |
193 | INIT_LIST_HEAD(&block->b_flist); | |
1da177e4 | 194 | |
92737230 | 195 | if (!nlmsvc_setgrantargs(call, lock)) |
1da177e4 LT |
196 | goto failed_free; |
197 | ||
198 | /* Set notifier function for VFS, and init args */ | |
92737230 TM |
199 | call->a_args.lock.fl.fl_flags |= FL_SLEEP; |
200 | call->a_args.lock.fl.fl_lmops = &nlmsvc_lock_operations; | |
39be4502 | 201 | nlmclnt_next_cookie(&call->a_args.cookie); |
1da177e4 LT |
202 | |
203 | dprintk("lockd: created block %p...\n", block); | |
204 | ||
205 | /* Create and initialize the block */ | |
206 | block->b_daemon = rqstp->rq_server; | |
207 | block->b_host = host; | |
208 | block->b_file = file; | |
5ea0d750 | 209 | block->b_fl = NULL; |
d9f6eb75 | 210 | file->f_count++; |
1da177e4 LT |
211 | |
212 | /* Add to file's list of blocks */ | |
68a2d76c | 213 | list_add(&block->b_flist, &file->f_blocks); |
1da177e4 LT |
214 | |
215 | /* Set up RPC arguments for callback */ | |
92737230 | 216 | block->b_call = call; |
1da177e4 | 217 | call->a_flags = RPC_TASK_ASYNC; |
92737230 | 218 | call->a_block = block; |
1da177e4 LT |
219 | |
220 | return block; | |
221 | ||
222 | failed_free: | |
223 | kfree(block); | |
224 | failed: | |
92737230 | 225 | nlm_release_call(call); |
1da177e4 LT |
226 | return NULL; |
227 | } | |
228 | ||
229 | /* | |
3c61eecb | 230 | * Delete a block. |
1da177e4 LT |
231 | * It is the caller's responsibility to check whether the file |
232 | * can be closed hereafter. | |
233 | */ | |
6849c0ca | 234 | static int nlmsvc_unlink_block(struct nlm_block *block) |
1da177e4 | 235 | { |
09c7938c | 236 | int status; |
6849c0ca | 237 | dprintk("lockd: unlinking block %p...\n", block); |
1da177e4 LT |
238 | |
239 | /* Remove block from list */ | |
92737230 | 240 | status = posix_unblock_lock(block->b_file->f_file, &block->b_call->a_args.lock.fl); |
1da177e4 | 241 | nlmsvc_remove_block(block); |
6849c0ca TM |
242 | return status; |
243 | } | |
1da177e4 | 244 | |
6849c0ca TM |
245 | static void nlmsvc_free_block(struct kref *kref) |
246 | { | |
247 | struct nlm_block *block = container_of(kref, struct nlm_block, b_count); | |
248 | struct nlm_file *file = block->b_file; | |
6849c0ca TM |
249 | |
250 | dprintk("lockd: freeing block %p...\n", block); | |
1da177e4 LT |
251 | |
252 | /* Remove block from file's list of blocks */ | |
89e63ef6 | 253 | mutex_lock(&file->f_mutex); |
68a2d76c | 254 | list_del_init(&block->b_flist); |
89e63ef6 | 255 | mutex_unlock(&file->f_mutex); |
1da177e4 | 256 | |
92737230 TM |
257 | nlmsvc_freegrantargs(block->b_call); |
258 | nlm_release_call(block->b_call); | |
d9f6eb75 | 259 | nlm_release_file(block->b_file); |
0e4ac9d9 | 260 | kfree(block->b_fl); |
1da177e4 | 261 | kfree(block); |
6849c0ca TM |
262 | } |
263 | ||
264 | static void nlmsvc_release_block(struct nlm_block *block) | |
265 | { | |
266 | if (block != NULL) | |
267 | kref_put(&block->b_count, nlmsvc_free_block); | |
1da177e4 LT |
268 | } |
269 | ||
f2af793d OK |
270 | /* |
271 | * Loop over all blocks and delete blocks held by | |
272 | * a matching host. | |
273 | */ | |
274 | void nlmsvc_traverse_blocks(struct nlm_host *host, | |
275 | struct nlm_file *file, | |
276 | nlm_host_match_fn_t match) | |
d9f6eb75 | 277 | { |
68a2d76c | 278 | struct nlm_block *block, *next; |
d9f6eb75 TM |
279 | |
280 | restart: | |
89e63ef6 | 281 | mutex_lock(&file->f_mutex); |
68a2d76c | 282 | list_for_each_entry_safe(block, next, &file->f_blocks, b_flist) { |
f2af793d | 283 | if (!match(block->b_host, host)) |
d9f6eb75 | 284 | continue; |
68a2d76c OK |
285 | /* Do not destroy blocks that are not on |
286 | * the global retry list - why? */ | |
287 | if (list_empty(&block->b_list)) | |
d9f6eb75 TM |
288 | continue; |
289 | kref_get(&block->b_count); | |
89e63ef6 | 290 | mutex_unlock(&file->f_mutex); |
d9f6eb75 TM |
291 | nlmsvc_unlink_block(block); |
292 | nlmsvc_release_block(block); | |
293 | goto restart; | |
294 | } | |
89e63ef6 | 295 | mutex_unlock(&file->f_mutex); |
d9f6eb75 TM |
296 | } |
297 | ||
5e1abf8c TM |
298 | /* |
299 | * Initialize arguments for GRANTED call. The nlm_rqst structure | |
300 | * has been cleared already. | |
301 | */ | |
302 | static int nlmsvc_setgrantargs(struct nlm_rqst *call, struct nlm_lock *lock) | |
303 | { | |
304 | locks_copy_lock(&call->a_args.lock.fl, &lock->fl); | |
305 | memcpy(&call->a_args.lock.fh, &lock->fh, sizeof(call->a_args.lock.fh)); | |
e9ff3990 | 306 | call->a_args.lock.caller = utsname()->nodename; |
5e1abf8c TM |
307 | call->a_args.lock.oh.len = lock->oh.len; |
308 | ||
309 | /* set default data area */ | |
310 | call->a_args.lock.oh.data = call->a_owner; | |
311 | call->a_args.lock.svid = lock->fl.fl_pid; | |
312 | ||
313 | if (lock->oh.len > NLMCLNT_OHSIZE) { | |
314 | void *data = kmalloc(lock->oh.len, GFP_KERNEL); | |
92737230 | 315 | if (!data) |
5e1abf8c | 316 | return 0; |
5e1abf8c TM |
317 | call->a_args.lock.oh.data = (u8 *) data; |
318 | } | |
319 | ||
320 | memcpy(call->a_args.lock.oh.data, lock->oh.data, lock->oh.len); | |
321 | return 1; | |
322 | } | |
323 | ||
324 | static void nlmsvc_freegrantargs(struct nlm_rqst *call) | |
325 | { | |
92737230 | 326 | if (call->a_args.lock.oh.data != call->a_owner) |
5e1abf8c | 327 | kfree(call->a_args.lock.oh.data); |
5e1abf8c TM |
328 | } |
329 | ||
2b36f412 ME |
330 | /* |
331 | * Deferred lock request handling for non-blocking lock | |
332 | */ | |
ca5c8cde | 333 | static __be32 |
2b36f412 ME |
334 | nlmsvc_defer_lock_rqst(struct svc_rqst *rqstp, struct nlm_block *block) |
335 | { | |
ca5c8cde | 336 | __be32 status = nlm_lck_denied_nolocks; |
2b36f412 ME |
337 | |
338 | block->b_flags |= B_QUEUED; | |
339 | ||
340 | nlmsvc_insert_block(block, NLM_TIMEOUT); | |
341 | ||
342 | block->b_cache_req = &rqstp->rq_chandle; | |
343 | if (rqstp->rq_chandle.defer) { | |
344 | block->b_deferred_req = | |
345 | rqstp->rq_chandle.defer(block->b_cache_req); | |
346 | if (block->b_deferred_req != NULL) | |
347 | status = nlm_drop_reply; | |
348 | } | |
349 | dprintk("lockd: nlmsvc_defer_lock_rqst block %p flags %d status %d\n", | |
ca5c8cde | 350 | block, block->b_flags, ntohl(status)); |
2b36f412 ME |
351 | |
352 | return status; | |
353 | } | |
354 | ||
1da177e4 LT |
355 | /* |
356 | * Attempt to establish a lock, and if it can't be granted, block it | |
357 | * if required. | |
358 | */ | |
52921e02 | 359 | __be32 |
1da177e4 | 360 | nlmsvc_lock(struct svc_rqst *rqstp, struct nlm_file *file, |
6cde4de8 JL |
361 | struct nlm_host *host, struct nlm_lock *lock, int wait, |
362 | struct nlm_cookie *cookie) | |
1da177e4 | 363 | { |
f8120480 | 364 | struct nlm_block *block = NULL; |
1da177e4 | 365 | int error; |
52921e02 | 366 | __be32 ret; |
1da177e4 LT |
367 | |
368 | dprintk("lockd: nlmsvc_lock(%s/%ld, ty=%d, pi=%d, %Ld-%Ld, bl=%d)\n", | |
225a719f JS |
369 | file->f_file->f_path.dentry->d_inode->i_sb->s_id, |
370 | file->f_file->f_path.dentry->d_inode->i_ino, | |
1da177e4 LT |
371 | lock->fl.fl_type, lock->fl.fl_pid, |
372 | (long long)lock->fl.fl_start, | |
373 | (long long)lock->fl.fl_end, | |
374 | wait); | |
375 | ||
1da177e4 | 376 | /* Lock file against concurrent access */ |
89e63ef6 | 377 | mutex_lock(&file->f_mutex); |
f8120480 ME |
378 | /* Get existing block (in case client is busy-waiting) |
379 | * or create new block | |
380 | */ | |
d9f6eb75 | 381 | block = nlmsvc_lookup_block(file, lock); |
09c7938c | 382 | if (block == NULL) { |
255129d1 | 383 | block = nlmsvc_create_block(rqstp, nlm_get_host(host), file, |
6d7bbbba | 384 | lock, cookie); |
f8120480 ME |
385 | ret = nlm_lck_denied_nolocks; |
386 | if (block == NULL) | |
387 | goto out; | |
92737230 | 388 | lock = &block->b_call->a_args.lock; |
f8120480 ME |
389 | } else |
390 | lock->fl.fl_flags &= ~FL_SLEEP; | |
1da177e4 | 391 | |
1a8322b2 ME |
392 | if (block->b_flags & B_QUEUED) { |
393 | dprintk("lockd: nlmsvc_lock deferred block %p flags %d\n", | |
394 | block, block->b_flags); | |
395 | if (block->b_granted) { | |
396 | nlmsvc_unlink_block(block); | |
397 | ret = nlm_granted; | |
398 | goto out; | |
399 | } | |
400 | if (block->b_flags & B_TIMED_OUT) { | |
401 | nlmsvc_unlink_block(block); | |
402 | ret = nlm_lck_denied; | |
403 | goto out; | |
404 | } | |
405 | ret = nlm_drop_reply; | |
406 | goto out; | |
407 | } | |
1da177e4 | 408 | |
1a8322b2 ME |
409 | if (!wait) |
410 | lock->fl.fl_flags &= ~FL_SLEEP; | |
411 | error = vfs_lock_file(file->f_file, F_SETLK, &lock->fl, NULL); | |
412 | lock->fl.fl_flags &= ~FL_SLEEP; | |
a85f193e | 413 | |
1a8322b2 | 414 | dprintk("lockd: vfs_lock_file returned %d\n", error); |
6d7bbbba | 415 | switch (error) { |
1da177e4 | 416 | case 0: |
15dadef9 AA |
417 | ret = nlm_granted; |
418 | goto out; | |
09c7938c | 419 | case -EAGAIN: |
1a8322b2 | 420 | ret = nlm_lck_denied; |
09c7938c | 421 | break; |
1a8322b2 ME |
422 | case -EINPROGRESS: |
423 | if (wait) | |
424 | break; | |
425 | /* Filesystem lock operation is in progress | |
426 | Add it to the queue waiting for callback */ | |
427 | ret = nlmsvc_defer_lock_rqst(rqstp, block); | |
428 | goto out; | |
09c7938c | 429 | case -EDEADLK: |
15dadef9 AA |
430 | ret = nlm_deadlock; |
431 | goto out; | |
1da177e4 | 432 | default: /* includes ENOLCK */ |
15dadef9 AA |
433 | ret = nlm_lck_denied_nolocks; |
434 | goto out; | |
1da177e4 LT |
435 | } |
436 | ||
09c7938c TM |
437 | ret = nlm_lck_denied; |
438 | if (!wait) | |
439 | goto out; | |
440 | ||
441 | ret = nlm_lck_blocked; | |
1da177e4 LT |
442 | |
443 | /* Append to list of blocked */ | |
f8120480 | 444 | nlmsvc_insert_block(block, NLM_NEVER); |
15dadef9 | 445 | out: |
89e63ef6 | 446 | mutex_unlock(&file->f_mutex); |
6849c0ca | 447 | nlmsvc_release_block(block); |
15dadef9 AA |
448 | dprintk("lockd: nlmsvc_lock returned %u\n", ret); |
449 | return ret; | |
1da177e4 LT |
450 | } |
451 | ||
452 | /* | |
453 | * Test for presence of a conflicting lock. | |
454 | */ | |
52921e02 | 455 | __be32 |
85f3f1b3 | 456 | nlmsvc_testlock(struct svc_rqst *rqstp, struct nlm_file *file, |
8f920d5e JL |
457 | struct nlm_host *host, struct nlm_lock *lock, |
458 | struct nlm_lock *conflock, struct nlm_cookie *cookie) | |
1da177e4 | 459 | { |
5ea0d750 ME |
460 | struct nlm_block *block = NULL; |
461 | int error; | |
462 | __be32 ret; | |
463 | ||
1da177e4 | 464 | dprintk("lockd: nlmsvc_testlock(%s/%ld, ty=%d, %Ld-%Ld)\n", |
225a719f JS |
465 | file->f_file->f_path.dentry->d_inode->i_sb->s_id, |
466 | file->f_file->f_path.dentry->d_inode->i_ino, | |
1da177e4 LT |
467 | lock->fl.fl_type, |
468 | (long long)lock->fl.fl_start, | |
469 | (long long)lock->fl.fl_end); | |
470 | ||
5ea0d750 ME |
471 | /* Get existing block (in case client is busy-waiting) */ |
472 | block = nlmsvc_lookup_block(file, lock); | |
473 | ||
474 | if (block == NULL) { | |
475 | struct file_lock *conf = kzalloc(sizeof(*conf), GFP_KERNEL); | |
476 | ||
477 | if (conf == NULL) | |
478 | return nlm_granted; | |
8f920d5e | 479 | nlm_get_host(host); |
255129d1 | 480 | block = nlmsvc_create_block(rqstp, host, file, lock, cookie); |
5ea0d750 ME |
481 | if (block == NULL) { |
482 | kfree(conf); | |
483 | return nlm_granted; | |
484 | } | |
485 | block->b_fl = conf; | |
486 | } | |
487 | if (block->b_flags & B_QUEUED) { | |
488 | dprintk("lockd: nlmsvc_testlock deferred block %p flags %d fl %p\n", | |
489 | block, block->b_flags, block->b_fl); | |
490 | if (block->b_flags & B_TIMED_OUT) { | |
491 | nlmsvc_unlink_block(block); | |
29dbf546 OD |
492 | ret = nlm_lck_denied; |
493 | goto out; | |
5ea0d750 ME |
494 | } |
495 | if (block->b_flags & B_GOT_CALLBACK) { | |
54ca95eb | 496 | nlmsvc_unlink_block(block); |
5ea0d750 ME |
497 | if (block->b_fl != NULL |
498 | && block->b_fl->fl_type != F_UNLCK) { | |
499 | lock->fl = *block->b_fl; | |
500 | goto conf_lock; | |
29dbf546 | 501 | } else { |
29dbf546 OD |
502 | ret = nlm_granted; |
503 | goto out; | |
5ea0d750 ME |
504 | } |
505 | } | |
29dbf546 OD |
506 | ret = nlm_drop_reply; |
507 | goto out; | |
1da177e4 LT |
508 | } |
509 | ||
5ea0d750 | 510 | error = vfs_test_lock(file->f_file, &lock->fl); |
29dbf546 OD |
511 | if (error == -EINPROGRESS) { |
512 | ret = nlmsvc_defer_lock_rqst(rqstp, block); | |
513 | goto out; | |
514 | } | |
5ea0d750 ME |
515 | if (error) { |
516 | ret = nlm_lck_denied_nolocks; | |
517 | goto out; | |
518 | } | |
519 | if (lock->fl.fl_type == F_UNLCK) { | |
520 | ret = nlm_granted; | |
521 | goto out; | |
522 | } | |
523 | ||
524 | conf_lock: | |
525 | dprintk("lockd: conflicting lock(ty=%d, %Ld-%Ld)\n", | |
526 | lock->fl.fl_type, (long long)lock->fl.fl_start, | |
527 | (long long)lock->fl.fl_end); | |
528 | conflock->caller = "somehost"; /* FIXME */ | |
529 | conflock->len = strlen(conflock->caller); | |
530 | conflock->oh.len = 0; /* don't return OH info */ | |
531 | conflock->svid = lock->fl.fl_pid; | |
532 | conflock->fl.fl_type = lock->fl.fl_type; | |
533 | conflock->fl.fl_start = lock->fl.fl_start; | |
534 | conflock->fl.fl_end = lock->fl.fl_end; | |
535 | ret = nlm_lck_denied; | |
536 | out: | |
537 | if (block) | |
538 | nlmsvc_release_block(block); | |
539 | return ret; | |
1da177e4 LT |
540 | } |
541 | ||
542 | /* | |
543 | * Remove a lock. | |
544 | * This implies a CANCEL call: We send a GRANT_MSG, the client replies | |
545 | * with a GRANT_RES call which gets lost, and calls UNLOCK immediately | |
546 | * afterwards. In this case the block will still be there, and hence | |
547 | * must be removed. | |
548 | */ | |
52921e02 | 549 | __be32 |
1da177e4 LT |
550 | nlmsvc_unlock(struct nlm_file *file, struct nlm_lock *lock) |
551 | { | |
552 | int error; | |
553 | ||
554 | dprintk("lockd: nlmsvc_unlock(%s/%ld, pi=%d, %Ld-%Ld)\n", | |
225a719f JS |
555 | file->f_file->f_path.dentry->d_inode->i_sb->s_id, |
556 | file->f_file->f_path.dentry->d_inode->i_ino, | |
1da177e4 LT |
557 | lock->fl.fl_pid, |
558 | (long long)lock->fl.fl_start, | |
559 | (long long)lock->fl.fl_end); | |
560 | ||
561 | /* First, cancel any lock that might be there */ | |
562 | nlmsvc_cancel_blocked(file, lock); | |
563 | ||
564 | lock->fl.fl_type = F_UNLCK; | |
1a8322b2 | 565 | error = vfs_lock_file(file->f_file, F_SETLK, &lock->fl, NULL); |
1da177e4 LT |
566 | |
567 | return (error < 0)? nlm_lck_denied_nolocks : nlm_granted; | |
568 | } | |
569 | ||
570 | /* | |
571 | * Cancel a previously blocked request. | |
572 | * | |
573 | * A cancel request always overrides any grant that may currently | |
574 | * be in progress. | |
575 | * The calling procedure must check whether the file can be closed. | |
576 | */ | |
52921e02 | 577 | __be32 |
1da177e4 LT |
578 | nlmsvc_cancel_blocked(struct nlm_file *file, struct nlm_lock *lock) |
579 | { | |
580 | struct nlm_block *block; | |
64a318ee | 581 | int status = 0; |
1da177e4 LT |
582 | |
583 | dprintk("lockd: nlmsvc_cancel(%s/%ld, pi=%d, %Ld-%Ld)\n", | |
225a719f JS |
584 | file->f_file->f_path.dentry->d_inode->i_sb->s_id, |
585 | file->f_file->f_path.dentry->d_inode->i_ino, | |
1da177e4 LT |
586 | lock->fl.fl_pid, |
587 | (long long)lock->fl.fl_start, | |
588 | (long long)lock->fl.fl_end); | |
589 | ||
89e63ef6 | 590 | mutex_lock(&file->f_mutex); |
d9f6eb75 | 591 | block = nlmsvc_lookup_block(file, lock); |
89e63ef6 | 592 | mutex_unlock(&file->f_mutex); |
d9f6eb75 | 593 | if (block != NULL) { |
1a8322b2 ME |
594 | vfs_cancel_lock(block->b_file->f_file, |
595 | &block->b_call->a_args.lock.fl); | |
6849c0ca TM |
596 | status = nlmsvc_unlink_block(block); |
597 | nlmsvc_release_block(block); | |
598 | } | |
64a318ee | 599 | return status ? nlm_lck_denied : nlm_granted; |
1da177e4 LT |
600 | } |
601 | ||
0e4ac9d9 ME |
602 | /* |
603 | * This is a callback from the filesystem for VFS file lock requests. | |
604 | * It will be used if fl_grant is defined and the filesystem can not | |
605 | * respond to the request immediately. | |
606 | * For GETLK request it will copy the reply to the nlm_block. | |
607 | * For SETLK or SETLKW request it will get the local posix lock. | |
608 | * In all cases it will move the block to the head of nlm_blocked q where | |
609 | * nlmsvc_retry_blocked() can send back a reply for SETLKW or revisit the | |
610 | * deferred rpc for GETLK and SETLK. | |
611 | */ | |
612 | static void | |
613 | nlmsvc_update_deferred_block(struct nlm_block *block, struct file_lock *conf, | |
614 | int result) | |
615 | { | |
616 | block->b_flags |= B_GOT_CALLBACK; | |
617 | if (result == 0) | |
618 | block->b_granted = 1; | |
619 | else | |
620 | block->b_flags |= B_TIMED_OUT; | |
621 | if (conf) { | |
0e4ac9d9 | 622 | if (block->b_fl) |
1a747ee0 | 623 | __locks_copy_lock(block->b_fl, conf); |
0e4ac9d9 ME |
624 | } |
625 | } | |
626 | ||
627 | static int nlmsvc_grant_deferred(struct file_lock *fl, struct file_lock *conf, | |
628 | int result) | |
629 | { | |
630 | struct nlm_block *block; | |
631 | int rc = -ENOENT; | |
632 | ||
633 | lock_kernel(); | |
634 | list_for_each_entry(block, &nlm_blocked, b_list) { | |
635 | if (nlm_compare_locks(&block->b_call->a_args.lock.fl, fl)) { | |
636 | dprintk("lockd: nlmsvc_notify_blocked block %p flags %d\n", | |
637 | block, block->b_flags); | |
638 | if (block->b_flags & B_QUEUED) { | |
639 | if (block->b_flags & B_TIMED_OUT) { | |
640 | rc = -ENOLCK; | |
641 | break; | |
642 | } | |
643 | nlmsvc_update_deferred_block(block, conf, result); | |
644 | } else if (result == 0) | |
645 | block->b_granted = 1; | |
646 | ||
647 | nlmsvc_insert_block(block, 0); | |
648 | svc_wake_up(block->b_daemon); | |
649 | rc = 0; | |
650 | break; | |
651 | } | |
652 | } | |
653 | unlock_kernel(); | |
654 | if (rc == -ENOENT) | |
655 | printk(KERN_WARNING "lockd: grant for unknown block\n"); | |
656 | return rc; | |
657 | } | |
658 | ||
1da177e4 LT |
659 | /* |
660 | * Unblock a blocked lock request. This is a callback invoked from the | |
661 | * VFS layer when a lock on which we blocked is removed. | |
662 | * | |
663 | * This function doesn't grant the blocked lock instantly, but rather moves | |
664 | * the block to the head of nlm_blocked where it can be picked up by lockd. | |
665 | */ | |
666 | static void | |
667 | nlmsvc_notify_blocked(struct file_lock *fl) | |
668 | { | |
68a2d76c | 669 | struct nlm_block *block; |
1da177e4 LT |
670 | |
671 | dprintk("lockd: VFS unblock notification for block %p\n", fl); | |
68a2d76c | 672 | list_for_each_entry(block, &nlm_blocked, b_list) { |
92737230 | 673 | if (nlm_compare_locks(&block->b_call->a_args.lock.fl, fl)) { |
1da177e4 LT |
674 | nlmsvc_insert_block(block, 0); |
675 | svc_wake_up(block->b_daemon); | |
676 | return; | |
677 | } | |
678 | } | |
679 | ||
680 | printk(KERN_WARNING "lockd: notification for unknown block!\n"); | |
681 | } | |
682 | ||
683 | static int nlmsvc_same_owner(struct file_lock *fl1, struct file_lock *fl2) | |
684 | { | |
685 | return fl1->fl_owner == fl2->fl_owner && fl1->fl_pid == fl2->fl_pid; | |
686 | } | |
687 | ||
688 | struct lock_manager_operations nlmsvc_lock_operations = { | |
689 | .fl_compare_owner = nlmsvc_same_owner, | |
690 | .fl_notify = nlmsvc_notify_blocked, | |
0e4ac9d9 | 691 | .fl_grant = nlmsvc_grant_deferred, |
1da177e4 LT |
692 | }; |
693 | ||
694 | /* | |
695 | * Try to claim a lock that was previously blocked. | |
696 | * | |
697 | * Note that we use both the RPC_GRANTED_MSG call _and_ an async | |
698 | * RPC thread when notifying the client. This seems like overkill... | |
699 | * Here's why: | |
700 | * - we don't want to use a synchronous RPC thread, otherwise | |
701 | * we might find ourselves hanging on a dead portmapper. | |
702 | * - Some lockd implementations (e.g. HP) don't react to | |
703 | * RPC_GRANTED calls; they seem to insist on RPC_GRANTED_MSG calls. | |
704 | */ | |
705 | static void | |
706 | nlmsvc_grant_blocked(struct nlm_block *block) | |
707 | { | |
708 | struct nlm_file *file = block->b_file; | |
92737230 | 709 | struct nlm_lock *lock = &block->b_call->a_args.lock; |
1da177e4 LT |
710 | int error; |
711 | ||
712 | dprintk("lockd: grant blocked lock %p\n", block); | |
713 | ||
0e4ac9d9 ME |
714 | kref_get(&block->b_count); |
715 | ||
1da177e4 | 716 | /* Unlink block request from list */ |
6849c0ca | 717 | nlmsvc_unlink_block(block); |
1da177e4 LT |
718 | |
719 | /* If b_granted is true this means we've been here before. | |
720 | * Just retry the grant callback, possibly refreshing the RPC | |
721 | * binding */ | |
722 | if (block->b_granted) { | |
723 | nlm_rebind_host(block->b_host); | |
724 | goto callback; | |
725 | } | |
726 | ||
727 | /* Try the lock operation again */ | |
09c7938c | 728 | lock->fl.fl_flags |= FL_SLEEP; |
1a8322b2 | 729 | error = vfs_lock_file(file->f_file, F_SETLK, &lock->fl, NULL); |
09c7938c TM |
730 | lock->fl.fl_flags &= ~FL_SLEEP; |
731 | ||
5de0e502 AA |
732 | switch (error) { |
733 | case 0: | |
734 | break; | |
735 | case -EAGAIN: | |
1a8322b2 ME |
736 | case -EINPROGRESS: |
737 | dprintk("lockd: lock still blocked error %d\n", error); | |
1da177e4 | 738 | nlmsvc_insert_block(block, NLM_NEVER); |
0e4ac9d9 | 739 | nlmsvc_release_block(block); |
d9f6eb75 | 740 | return; |
5de0e502 | 741 | default: |
1da177e4 | 742 | printk(KERN_WARNING "lockd: unexpected error %d in %s!\n", |
8e24eea7 | 743 | -error, __func__); |
1da177e4 | 744 | nlmsvc_insert_block(block, 10 * HZ); |
0e4ac9d9 | 745 | nlmsvc_release_block(block); |
d9f6eb75 | 746 | return; |
1da177e4 LT |
747 | } |
748 | ||
749 | callback: | |
750 | /* Lock was granted by VFS. */ | |
751 | dprintk("lockd: GRANTing blocked lock.\n"); | |
752 | block->b_granted = 1; | |
1da177e4 | 753 | |
9706501e JL |
754 | /* keep block on the list, but don't reattempt until the RPC |
755 | * completes or the submission fails | |
756 | */ | |
757 | nlmsvc_insert_block(block, NLM_NEVER); | |
1da177e4 | 758 | |
9706501e JL |
759 | /* Call the client -- use a soft RPC task since nlmsvc_retry_blocked |
760 | * will queue up a new one if this one times out | |
761 | */ | |
762 | error = nlm_async_call(block->b_call, NLMPROC_GRANTED_MSG, | |
763 | &nlmsvc_grant_ops); | |
764 | ||
765 | /* RPC submission failed, wait a bit and retry */ | |
766 | if (error < 0) | |
767 | nlmsvc_insert_block(block, 10 * HZ); | |
1da177e4 LT |
768 | } |
769 | ||
770 | /* | |
771 | * This is the callback from the RPC layer when the NLM_GRANTED_MSG | |
772 | * RPC call has succeeded or timed out. | |
773 | * Like all RPC callbacks, it is invoked by the rpciod process, so it | |
774 | * better not sleep. Therefore, we put the blocked lock on the nlm_blocked | |
775 | * chain once more in order to have it removed by lockd itself (which can | |
776 | * then sleep on the file semaphore without disrupting e.g. the nfs client). | |
777 | */ | |
963d8fe5 | 778 | static void nlmsvc_grant_callback(struct rpc_task *task, void *data) |
1da177e4 | 779 | { |
963d8fe5 | 780 | struct nlm_rqst *call = data; |
92737230 | 781 | struct nlm_block *block = call->a_block; |
1da177e4 | 782 | unsigned long timeout; |
1da177e4 LT |
783 | |
784 | dprintk("lockd: GRANT_MSG RPC callback\n"); | |
1da177e4 | 785 | |
c64e80d5 JL |
786 | /* if the block is not on a list at this point then it has |
787 | * been invalidated. Don't try to requeue it. | |
788 | * | |
789 | * FIXME: it's possible that the block is removed from the list | |
790 | * after this check but before the nlmsvc_insert_block. In that | |
791 | * case it will be added back. Perhaps we need better locking | |
792 | * for nlm_blocked? | |
793 | */ | |
794 | if (list_empty(&block->b_list)) | |
795 | return; | |
796 | ||
1da177e4 LT |
797 | /* Technically, we should down the file semaphore here. Since we |
798 | * move the block towards the head of the queue only, no harm | |
799 | * can be done, though. */ | |
800 | if (task->tk_status < 0) { | |
801 | /* RPC error: Re-insert for retransmission */ | |
802 | timeout = 10 * HZ; | |
1da177e4 LT |
803 | } else { |
804 | /* Call was successful, now wait for client callback */ | |
805 | timeout = 60 * HZ; | |
806 | } | |
807 | nlmsvc_insert_block(block, timeout); | |
808 | svc_wake_up(block->b_daemon); | |
5e1abf8c TM |
809 | } |
810 | ||
ec535ce1 | 811 | static void nlmsvc_grant_release(void *data) |
5e1abf8c | 812 | { |
6041b791 TM |
813 | struct nlm_rqst *call = data; |
814 | ||
815 | nlmsvc_release_block(call->a_block); | |
1da177e4 LT |
816 | } |
817 | ||
963d8fe5 TM |
818 | static const struct rpc_call_ops nlmsvc_grant_ops = { |
819 | .rpc_call_done = nlmsvc_grant_callback, | |
5e1abf8c | 820 | .rpc_release = nlmsvc_grant_release, |
963d8fe5 TM |
821 | }; |
822 | ||
1da177e4 LT |
823 | /* |
824 | * We received a GRANT_RES callback. Try to find the corresponding | |
825 | * block. | |
826 | */ | |
827 | void | |
e8c5c045 | 828 | nlmsvc_grant_reply(struct nlm_cookie *cookie, __be32 status) |
1da177e4 LT |
829 | { |
830 | struct nlm_block *block; | |
1da177e4 | 831 | |
39be4502 OK |
832 | dprintk("grant_reply: looking for cookie %x, s=%d \n", |
833 | *(unsigned int *)(cookie->data), status); | |
834 | if (!(block = nlmsvc_find_block(cookie))) | |
1da177e4 | 835 | return; |
1da177e4 | 836 | |
f232142c | 837 | if (block) { |
e8c5c045 | 838 | if (status == nlm_lck_denied_grace_period) { |
1da177e4 LT |
839 | /* Try again in a couple of seconds */ |
840 | nlmsvc_insert_block(block, 10 * HZ); | |
1da177e4 LT |
841 | } else { |
842 | /* Lock is now held by client, or has been rejected. | |
843 | * In both cases, the block should be removed. */ | |
6849c0ca | 844 | nlmsvc_unlink_block(block); |
1da177e4 LT |
845 | } |
846 | } | |
6849c0ca | 847 | nlmsvc_release_block(block); |
1da177e4 LT |
848 | } |
849 | ||
0e4ac9d9 ME |
850 | /* Helper function to handle retry of a deferred block. |
851 | * If it is a blocking lock, call grant_blocked. | |
852 | * For a non-blocking lock or test lock, revisit the request. | |
853 | */ | |
854 | static void | |
855 | retry_deferred_block(struct nlm_block *block) | |
856 | { | |
857 | if (!(block->b_flags & B_GOT_CALLBACK)) | |
858 | block->b_flags |= B_TIMED_OUT; | |
859 | nlmsvc_insert_block(block, NLM_TIMEOUT); | |
860 | dprintk("revisit block %p flags %d\n", block, block->b_flags); | |
861 | if (block->b_deferred_req) { | |
862 | block->b_deferred_req->revisit(block->b_deferred_req, 0); | |
863 | block->b_deferred_req = NULL; | |
864 | } | |
865 | } | |
866 | ||
1da177e4 LT |
867 | /* |
868 | * Retry all blocked locks that have been notified. This is where lockd | |
869 | * picks up locks that can be granted, or grant notifications that must | |
870 | * be retransmitted. | |
871 | */ | |
872 | unsigned long | |
873 | nlmsvc_retry_blocked(void) | |
874 | { | |
68a2d76c OK |
875 | unsigned long timeout = MAX_SCHEDULE_TIMEOUT; |
876 | struct nlm_block *block; | |
877 | ||
d751a7cd | 878 | while (!list_empty(&nlm_blocked) && !kthread_should_stop()) { |
68a2d76c | 879 | block = list_entry(nlm_blocked.next, struct nlm_block, b_list); |
1da177e4 | 880 | |
1da177e4 LT |
881 | if (block->b_when == NLM_NEVER) |
882 | break; | |
6d7bbbba | 883 | if (time_after(block->b_when, jiffies)) { |
68a2d76c | 884 | timeout = block->b_when - jiffies; |
1da177e4 | 885 | break; |
68a2d76c OK |
886 | } |
887 | ||
f3d43c76 BF |
888 | dprintk("nlmsvc_retry_blocked(%p, when=%ld)\n", |
889 | block, block->b_when); | |
0e4ac9d9 ME |
890 | if (block->b_flags & B_QUEUED) { |
891 | dprintk("nlmsvc_retry_blocked delete block (%p, granted=%d, flags=%d)\n", | |
892 | block, block->b_granted, block->b_flags); | |
893 | retry_deferred_block(block); | |
894 | } else | |
895 | nlmsvc_grant_blocked(block); | |
1da177e4 LT |
896 | } |
897 | ||
68a2d76c | 898 | return timeout; |
1da177e4 | 899 | } |