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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 * | |
39be4502 | 142 | nlmsvc_find_block(struct nlm_cookie *cookie) |
1da177e4 LT |
143 | { |
144 | struct nlm_block *block; | |
145 | ||
68a2d76c | 146 | list_for_each_entry(block, &nlm_blocked, b_list) { |
39be4502 | 147 | if (nlm_cookie_match(&block->b_call->a_args.cookie,cookie)) |
68a2d76c | 148 | goto found; |
1da177e4 LT |
149 | } |
150 | ||
68a2d76c OK |
151 | return NULL; |
152 | ||
153 | found: | |
39be4502 | 154 | dprintk("nlmsvc_find_block(%s): block=%p\n", nlmdbg_cookie2a(cookie), block); |
68a2d76c | 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. | |
39be4502 OK |
168 | * |
169 | * 10 years later: I hope we can safely ignore these old and broken | |
170 | * clients by now. Let's fix this so we can uniquely identify an incoming | |
171 | * GRANTED_RES message by cookie, without having to rely on the client's IP | |
172 | * address. --okir | |
1da177e4 LT |
173 | */ |
174 | static inline struct nlm_block * | |
175 | nlmsvc_create_block(struct svc_rqst *rqstp, struct nlm_file *file, | |
176 | struct nlm_lock *lock, struct nlm_cookie *cookie) | |
177 | { | |
178 | struct nlm_block *block; | |
179 | struct nlm_host *host; | |
92737230 | 180 | struct nlm_rqst *call = NULL; |
1da177e4 LT |
181 | |
182 | /* Create host handle for callback */ | |
db4e4c9a | 183 | host = nlmsvc_lookup_host(rqstp, lock->caller, lock->len); |
1da177e4 LT |
184 | if (host == NULL) |
185 | return NULL; | |
186 | ||
92737230 TM |
187 | call = nlm_alloc_call(host); |
188 | if (call == NULL) | |
189 | return NULL; | |
190 | ||
1da177e4 | 191 | /* Allocate memory for block, and initialize arguments */ |
92737230 TM |
192 | block = kzalloc(sizeof(*block), GFP_KERNEL); |
193 | if (block == NULL) | |
1da177e4 | 194 | goto failed; |
6849c0ca | 195 | kref_init(&block->b_count); |
68a2d76c OK |
196 | INIT_LIST_HEAD(&block->b_list); |
197 | INIT_LIST_HEAD(&block->b_flist); | |
1da177e4 | 198 | |
92737230 | 199 | if (!nlmsvc_setgrantargs(call, lock)) |
1da177e4 LT |
200 | goto failed_free; |
201 | ||
202 | /* Set notifier function for VFS, and init args */ | |
92737230 TM |
203 | call->a_args.lock.fl.fl_flags |= FL_SLEEP; |
204 | call->a_args.lock.fl.fl_lmops = &nlmsvc_lock_operations; | |
39be4502 | 205 | nlmclnt_next_cookie(&call->a_args.cookie); |
1da177e4 LT |
206 | |
207 | dprintk("lockd: created block %p...\n", block); | |
208 | ||
209 | /* Create and initialize the block */ | |
210 | block->b_daemon = rqstp->rq_server; | |
211 | block->b_host = host; | |
212 | block->b_file = file; | |
d9f6eb75 | 213 | file->f_count++; |
1da177e4 LT |
214 | |
215 | /* Add to file's list of blocks */ | |
68a2d76c | 216 | list_add(&block->b_flist, &file->f_blocks); |
1da177e4 LT |
217 | |
218 | /* Set up RPC arguments for callback */ | |
92737230 | 219 | block->b_call = call; |
1da177e4 | 220 | call->a_flags = RPC_TASK_ASYNC; |
92737230 | 221 | call->a_block = block; |
1da177e4 LT |
222 | |
223 | return block; | |
224 | ||
225 | failed_free: | |
226 | kfree(block); | |
227 | failed: | |
92737230 | 228 | nlm_release_call(call); |
1da177e4 LT |
229 | return NULL; |
230 | } | |
231 | ||
232 | /* | |
233 | * Delete a block. If the lock was cancelled or the grant callback | |
234 | * failed, unlock is set to 1. | |
235 | * It is the caller's responsibility to check whether the file | |
236 | * can be closed hereafter. | |
237 | */ | |
6849c0ca | 238 | static int nlmsvc_unlink_block(struct nlm_block *block) |
1da177e4 | 239 | { |
09c7938c | 240 | int status; |
6849c0ca | 241 | dprintk("lockd: unlinking block %p...\n", block); |
1da177e4 LT |
242 | |
243 | /* Remove block from list */ | |
92737230 | 244 | status = posix_unblock_lock(block->b_file->f_file, &block->b_call->a_args.lock.fl); |
1da177e4 | 245 | nlmsvc_remove_block(block); |
6849c0ca TM |
246 | return status; |
247 | } | |
1da177e4 | 248 | |
6849c0ca TM |
249 | static void nlmsvc_free_block(struct kref *kref) |
250 | { | |
251 | struct nlm_block *block = container_of(kref, struct nlm_block, b_count); | |
252 | struct nlm_file *file = block->b_file; | |
6849c0ca TM |
253 | |
254 | dprintk("lockd: freeing block %p...\n", block); | |
1da177e4 LT |
255 | |
256 | /* Remove block from file's list of blocks */ | |
89e63ef6 | 257 | mutex_lock(&file->f_mutex); |
68a2d76c | 258 | list_del_init(&block->b_flist); |
89e63ef6 | 259 | mutex_unlock(&file->f_mutex); |
1da177e4 | 260 | |
92737230 TM |
261 | nlmsvc_freegrantargs(block->b_call); |
262 | nlm_release_call(block->b_call); | |
d9f6eb75 | 263 | nlm_release_file(block->b_file); |
1da177e4 | 264 | kfree(block); |
6849c0ca TM |
265 | } |
266 | ||
267 | static void nlmsvc_release_block(struct nlm_block *block) | |
268 | { | |
269 | if (block != NULL) | |
270 | kref_put(&block->b_count, nlmsvc_free_block); | |
1da177e4 LT |
271 | } |
272 | ||
f2af793d OK |
273 | /* |
274 | * Loop over all blocks and delete blocks held by | |
275 | * a matching host. | |
276 | */ | |
277 | void nlmsvc_traverse_blocks(struct nlm_host *host, | |
278 | struct nlm_file *file, | |
279 | nlm_host_match_fn_t match) | |
d9f6eb75 | 280 | { |
68a2d76c | 281 | struct nlm_block *block, *next; |
d9f6eb75 TM |
282 | |
283 | restart: | |
89e63ef6 | 284 | mutex_lock(&file->f_mutex); |
68a2d76c | 285 | list_for_each_entry_safe(block, next, &file->f_blocks, b_flist) { |
f2af793d | 286 | if (!match(block->b_host, host)) |
d9f6eb75 | 287 | continue; |
68a2d76c OK |
288 | /* Do not destroy blocks that are not on |
289 | * the global retry list - why? */ | |
290 | if (list_empty(&block->b_list)) | |
d9f6eb75 TM |
291 | continue; |
292 | kref_get(&block->b_count); | |
89e63ef6 | 293 | mutex_unlock(&file->f_mutex); |
d9f6eb75 TM |
294 | nlmsvc_unlink_block(block); |
295 | nlmsvc_release_block(block); | |
296 | goto restart; | |
297 | } | |
89e63ef6 | 298 | mutex_unlock(&file->f_mutex); |
d9f6eb75 TM |
299 | } |
300 | ||
5e1abf8c TM |
301 | /* |
302 | * Initialize arguments for GRANTED call. The nlm_rqst structure | |
303 | * has been cleared already. | |
304 | */ | |
305 | static int nlmsvc_setgrantargs(struct nlm_rqst *call, struct nlm_lock *lock) | |
306 | { | |
307 | locks_copy_lock(&call->a_args.lock.fl, &lock->fl); | |
308 | memcpy(&call->a_args.lock.fh, &lock->fh, sizeof(call->a_args.lock.fh)); | |
e9ff3990 | 309 | call->a_args.lock.caller = utsname()->nodename; |
5e1abf8c TM |
310 | call->a_args.lock.oh.len = lock->oh.len; |
311 | ||
312 | /* set default data area */ | |
313 | call->a_args.lock.oh.data = call->a_owner; | |
314 | call->a_args.lock.svid = lock->fl.fl_pid; | |
315 | ||
316 | if (lock->oh.len > NLMCLNT_OHSIZE) { | |
317 | void *data = kmalloc(lock->oh.len, GFP_KERNEL); | |
92737230 | 318 | if (!data) |
5e1abf8c | 319 | return 0; |
5e1abf8c TM |
320 | call->a_args.lock.oh.data = (u8 *) data; |
321 | } | |
322 | ||
323 | memcpy(call->a_args.lock.oh.data, lock->oh.data, lock->oh.len); | |
324 | return 1; | |
325 | } | |
326 | ||
327 | static void nlmsvc_freegrantargs(struct nlm_rqst *call) | |
328 | { | |
92737230 | 329 | if (call->a_args.lock.oh.data != call->a_owner) |
5e1abf8c | 330 | kfree(call->a_args.lock.oh.data); |
5e1abf8c TM |
331 | } |
332 | ||
2b36f412 ME |
333 | /* |
334 | * Deferred lock request handling for non-blocking lock | |
335 | */ | |
336 | static u32 | |
337 | nlmsvc_defer_lock_rqst(struct svc_rqst *rqstp, struct nlm_block *block) | |
338 | { | |
339 | u32 status = nlm_lck_denied_nolocks; | |
340 | ||
341 | block->b_flags |= B_QUEUED; | |
342 | ||
343 | nlmsvc_insert_block(block, NLM_TIMEOUT); | |
344 | ||
345 | block->b_cache_req = &rqstp->rq_chandle; | |
346 | if (rqstp->rq_chandle.defer) { | |
347 | block->b_deferred_req = | |
348 | rqstp->rq_chandle.defer(block->b_cache_req); | |
349 | if (block->b_deferred_req != NULL) | |
350 | status = nlm_drop_reply; | |
351 | } | |
352 | dprintk("lockd: nlmsvc_defer_lock_rqst block %p flags %d status %d\n", | |
353 | block, block->b_flags, status); | |
354 | ||
355 | return status; | |
356 | } | |
357 | ||
1da177e4 LT |
358 | /* |
359 | * Attempt to establish a lock, and if it can't be granted, block it | |
360 | * if required. | |
361 | */ | |
52921e02 | 362 | __be32 |
1da177e4 LT |
363 | nlmsvc_lock(struct svc_rqst *rqstp, struct nlm_file *file, |
364 | struct nlm_lock *lock, int wait, struct nlm_cookie *cookie) | |
365 | { | |
09c7938c | 366 | struct nlm_block *block, *newblock = NULL; |
1da177e4 | 367 | int error; |
52921e02 | 368 | __be32 ret; |
1da177e4 LT |
369 | |
370 | dprintk("lockd: nlmsvc_lock(%s/%ld, ty=%d, pi=%d, %Ld-%Ld, bl=%d)\n", | |
225a719f JS |
371 | file->f_file->f_path.dentry->d_inode->i_sb->s_id, |
372 | file->f_file->f_path.dentry->d_inode->i_ino, | |
1da177e4 LT |
373 | lock->fl.fl_type, lock->fl.fl_pid, |
374 | (long long)lock->fl.fl_start, | |
375 | (long long)lock->fl.fl_end, | |
376 | wait); | |
377 | ||
378 | ||
09c7938c | 379 | lock->fl.fl_flags &= ~FL_SLEEP; |
1da177e4 LT |
380 | again: |
381 | /* Lock file against concurrent access */ | |
89e63ef6 | 382 | mutex_lock(&file->f_mutex); |
09c7938c | 383 | /* Get existing block (in case client is busy-waiting) */ |
d9f6eb75 | 384 | block = nlmsvc_lookup_block(file, lock); |
09c7938c TM |
385 | if (block == NULL) { |
386 | if (newblock != NULL) | |
92737230 | 387 | lock = &newblock->b_call->a_args.lock; |
09c7938c | 388 | } else |
92737230 | 389 | lock = &block->b_call->a_args.lock; |
1da177e4 | 390 | |
150b3934 | 391 | error = posix_lock_file(file->f_file, &lock->fl, NULL); |
09c7938c | 392 | lock->fl.fl_flags &= ~FL_SLEEP; |
1da177e4 | 393 | |
a85f193e AA |
394 | dprintk("lockd: posix_lock_file returned %d\n", error); |
395 | ||
09c7938c | 396 | switch(error) { |
1da177e4 | 397 | case 0: |
15dadef9 AA |
398 | ret = nlm_granted; |
399 | goto out; | |
09c7938c TM |
400 | case -EAGAIN: |
401 | break; | |
402 | case -EDEADLK: | |
15dadef9 AA |
403 | ret = nlm_deadlock; |
404 | goto out; | |
1da177e4 | 405 | default: /* includes ENOLCK */ |
15dadef9 AA |
406 | ret = nlm_lck_denied_nolocks; |
407 | goto out; | |
1da177e4 LT |
408 | } |
409 | ||
09c7938c TM |
410 | ret = nlm_lck_denied; |
411 | if (!wait) | |
412 | goto out; | |
413 | ||
414 | ret = nlm_lck_blocked; | |
415 | if (block != NULL) | |
416 | goto out; | |
1da177e4 | 417 | |
1da177e4 LT |
418 | /* If we don't have a block, create and initialize it. Then |
419 | * retry because we may have slept in kmalloc. */ | |
89e63ef6 | 420 | /* We have to release f_mutex as nlmsvc_create_block may try to |
1da177e4 | 421 | * to claim it while doing host garbage collection */ |
09c7938c | 422 | if (newblock == NULL) { |
89e63ef6 | 423 | mutex_unlock(&file->f_mutex); |
1da177e4 | 424 | dprintk("lockd: blocking on this lock (allocating).\n"); |
09c7938c | 425 | if (!(newblock = nlmsvc_create_block(rqstp, file, lock, cookie))) |
1da177e4 LT |
426 | return nlm_lck_denied_nolocks; |
427 | goto again; | |
428 | } | |
429 | ||
430 | /* Append to list of blocked */ | |
09c7938c | 431 | nlmsvc_insert_block(newblock, NLM_NEVER); |
15dadef9 | 432 | out: |
89e63ef6 | 433 | mutex_unlock(&file->f_mutex); |
6849c0ca TM |
434 | nlmsvc_release_block(newblock); |
435 | nlmsvc_release_block(block); | |
15dadef9 AA |
436 | dprintk("lockd: nlmsvc_lock returned %u\n", ret); |
437 | return ret; | |
1da177e4 LT |
438 | } |
439 | ||
440 | /* | |
441 | * Test for presence of a conflicting lock. | |
442 | */ | |
52921e02 | 443 | __be32 |
1da177e4 LT |
444 | nlmsvc_testlock(struct nlm_file *file, struct nlm_lock *lock, |
445 | struct nlm_lock *conflock) | |
446 | { | |
1da177e4 | 447 | dprintk("lockd: nlmsvc_testlock(%s/%ld, ty=%d, %Ld-%Ld)\n", |
225a719f JS |
448 | file->f_file->f_path.dentry->d_inode->i_sb->s_id, |
449 | file->f_file->f_path.dentry->d_inode->i_ino, | |
1da177e4 LT |
450 | lock->fl.fl_type, |
451 | (long long)lock->fl.fl_start, | |
452 | (long long)lock->fl.fl_end); | |
453 | ||
9d6a8c5c | 454 | if (posix_test_lock(file->f_file, &lock->fl)) { |
1da177e4 | 455 | dprintk("lockd: conflicting lock(ty=%d, %Ld-%Ld)\n", |
9d6a8c5c ME |
456 | lock->fl.fl_type, |
457 | (long long)lock->fl.fl_start, | |
458 | (long long)lock->fl.fl_end); | |
1da177e4 | 459 | conflock->caller = "somehost"; /* FIXME */ |
db4e4c9a | 460 | conflock->len = strlen(conflock->caller); |
1da177e4 | 461 | conflock->oh.len = 0; /* don't return OH info */ |
9d6a8c5c ME |
462 | conflock->svid = lock->fl.fl_pid; |
463 | conflock->fl.fl_type = lock->fl.fl_type; | |
464 | conflock->fl.fl_start = lock->fl.fl_start; | |
465 | conflock->fl.fl_end = lock->fl.fl_end; | |
1da177e4 LT |
466 | return nlm_lck_denied; |
467 | } | |
468 | ||
469 | return nlm_granted; | |
470 | } | |
471 | ||
472 | /* | |
473 | * Remove a lock. | |
474 | * This implies a CANCEL call: We send a GRANT_MSG, the client replies | |
475 | * with a GRANT_RES call which gets lost, and calls UNLOCK immediately | |
476 | * afterwards. In this case the block will still be there, and hence | |
477 | * must be removed. | |
478 | */ | |
52921e02 | 479 | __be32 |
1da177e4 LT |
480 | nlmsvc_unlock(struct nlm_file *file, struct nlm_lock *lock) |
481 | { | |
482 | int error; | |
483 | ||
484 | dprintk("lockd: nlmsvc_unlock(%s/%ld, pi=%d, %Ld-%Ld)\n", | |
225a719f JS |
485 | file->f_file->f_path.dentry->d_inode->i_sb->s_id, |
486 | file->f_file->f_path.dentry->d_inode->i_ino, | |
1da177e4 LT |
487 | lock->fl.fl_pid, |
488 | (long long)lock->fl.fl_start, | |
489 | (long long)lock->fl.fl_end); | |
490 | ||
491 | /* First, cancel any lock that might be there */ | |
492 | nlmsvc_cancel_blocked(file, lock); | |
493 | ||
494 | lock->fl.fl_type = F_UNLCK; | |
150b3934 | 495 | error = posix_lock_file(file->f_file, &lock->fl, NULL); |
1da177e4 LT |
496 | |
497 | return (error < 0)? nlm_lck_denied_nolocks : nlm_granted; | |
498 | } | |
499 | ||
500 | /* | |
501 | * Cancel a previously blocked request. | |
502 | * | |
503 | * A cancel request always overrides any grant that may currently | |
504 | * be in progress. | |
505 | * The calling procedure must check whether the file can be closed. | |
506 | */ | |
52921e02 | 507 | __be32 |
1da177e4 LT |
508 | nlmsvc_cancel_blocked(struct nlm_file *file, struct nlm_lock *lock) |
509 | { | |
510 | struct nlm_block *block; | |
64a318ee | 511 | int status = 0; |
1da177e4 LT |
512 | |
513 | dprintk("lockd: nlmsvc_cancel(%s/%ld, pi=%d, %Ld-%Ld)\n", | |
225a719f JS |
514 | file->f_file->f_path.dentry->d_inode->i_sb->s_id, |
515 | file->f_file->f_path.dentry->d_inode->i_ino, | |
1da177e4 LT |
516 | lock->fl.fl_pid, |
517 | (long long)lock->fl.fl_start, | |
518 | (long long)lock->fl.fl_end); | |
519 | ||
89e63ef6 | 520 | mutex_lock(&file->f_mutex); |
d9f6eb75 | 521 | block = nlmsvc_lookup_block(file, lock); |
89e63ef6 | 522 | mutex_unlock(&file->f_mutex); |
d9f6eb75 | 523 | if (block != NULL) { |
6849c0ca TM |
524 | status = nlmsvc_unlink_block(block); |
525 | nlmsvc_release_block(block); | |
526 | } | |
64a318ee | 527 | return status ? nlm_lck_denied : nlm_granted; |
1da177e4 LT |
528 | } |
529 | ||
530 | /* | |
531 | * Unblock a blocked lock request. This is a callback invoked from the | |
532 | * VFS layer when a lock on which we blocked is removed. | |
533 | * | |
534 | * This function doesn't grant the blocked lock instantly, but rather moves | |
535 | * the block to the head of nlm_blocked where it can be picked up by lockd. | |
536 | */ | |
537 | static void | |
538 | nlmsvc_notify_blocked(struct file_lock *fl) | |
539 | { | |
68a2d76c | 540 | struct nlm_block *block; |
1da177e4 LT |
541 | |
542 | dprintk("lockd: VFS unblock notification for block %p\n", fl); | |
68a2d76c | 543 | list_for_each_entry(block, &nlm_blocked, b_list) { |
92737230 | 544 | if (nlm_compare_locks(&block->b_call->a_args.lock.fl, fl)) { |
1da177e4 LT |
545 | nlmsvc_insert_block(block, 0); |
546 | svc_wake_up(block->b_daemon); | |
547 | return; | |
548 | } | |
549 | } | |
550 | ||
551 | printk(KERN_WARNING "lockd: notification for unknown block!\n"); | |
552 | } | |
553 | ||
554 | static int nlmsvc_same_owner(struct file_lock *fl1, struct file_lock *fl2) | |
555 | { | |
556 | return fl1->fl_owner == fl2->fl_owner && fl1->fl_pid == fl2->fl_pid; | |
557 | } | |
558 | ||
559 | struct lock_manager_operations nlmsvc_lock_operations = { | |
560 | .fl_compare_owner = nlmsvc_same_owner, | |
561 | .fl_notify = nlmsvc_notify_blocked, | |
562 | }; | |
563 | ||
564 | /* | |
565 | * Try to claim a lock that was previously blocked. | |
566 | * | |
567 | * Note that we use both the RPC_GRANTED_MSG call _and_ an async | |
568 | * RPC thread when notifying the client. This seems like overkill... | |
569 | * Here's why: | |
570 | * - we don't want to use a synchronous RPC thread, otherwise | |
571 | * we might find ourselves hanging on a dead portmapper. | |
572 | * - Some lockd implementations (e.g. HP) don't react to | |
573 | * RPC_GRANTED calls; they seem to insist on RPC_GRANTED_MSG calls. | |
574 | */ | |
575 | static void | |
576 | nlmsvc_grant_blocked(struct nlm_block *block) | |
577 | { | |
578 | struct nlm_file *file = block->b_file; | |
92737230 | 579 | struct nlm_lock *lock = &block->b_call->a_args.lock; |
1da177e4 LT |
580 | int error; |
581 | ||
582 | dprintk("lockd: grant blocked lock %p\n", block); | |
583 | ||
1da177e4 | 584 | /* Unlink block request from list */ |
6849c0ca | 585 | nlmsvc_unlink_block(block); |
1da177e4 LT |
586 | |
587 | /* If b_granted is true this means we've been here before. | |
588 | * Just retry the grant callback, possibly refreshing the RPC | |
589 | * binding */ | |
590 | if (block->b_granted) { | |
591 | nlm_rebind_host(block->b_host); | |
592 | goto callback; | |
593 | } | |
594 | ||
595 | /* Try the lock operation again */ | |
09c7938c | 596 | lock->fl.fl_flags |= FL_SLEEP; |
150b3934 | 597 | error = posix_lock_file(file->f_file, &lock->fl, NULL); |
09c7938c TM |
598 | lock->fl.fl_flags &= ~FL_SLEEP; |
599 | ||
5de0e502 AA |
600 | switch (error) { |
601 | case 0: | |
602 | break; | |
603 | case -EAGAIN: | |
1da177e4 LT |
604 | dprintk("lockd: lock still blocked\n"); |
605 | nlmsvc_insert_block(block, NLM_NEVER); | |
d9f6eb75 | 606 | return; |
5de0e502 | 607 | default: |
1da177e4 LT |
608 | printk(KERN_WARNING "lockd: unexpected error %d in %s!\n", |
609 | -error, __FUNCTION__); | |
610 | nlmsvc_insert_block(block, 10 * HZ); | |
d9f6eb75 | 611 | return; |
1da177e4 LT |
612 | } |
613 | ||
614 | callback: | |
615 | /* Lock was granted by VFS. */ | |
616 | dprintk("lockd: GRANTing blocked lock.\n"); | |
617 | block->b_granted = 1; | |
1da177e4 LT |
618 | |
619 | /* Schedule next grant callback in 30 seconds */ | |
620 | nlmsvc_insert_block(block, 30 * HZ); | |
621 | ||
622 | /* Call the client */ | |
6849c0ca | 623 | kref_get(&block->b_count); |
a995e9eb | 624 | nlm_async_call(block->b_call, NLMPROC_GRANTED_MSG, &nlmsvc_grant_ops); |
1da177e4 LT |
625 | } |
626 | ||
627 | /* | |
628 | * This is the callback from the RPC layer when the NLM_GRANTED_MSG | |
629 | * RPC call has succeeded or timed out. | |
630 | * Like all RPC callbacks, it is invoked by the rpciod process, so it | |
631 | * better not sleep. Therefore, we put the blocked lock on the nlm_blocked | |
632 | * chain once more in order to have it removed by lockd itself (which can | |
633 | * then sleep on the file semaphore without disrupting e.g. the nfs client). | |
634 | */ | |
963d8fe5 | 635 | static void nlmsvc_grant_callback(struct rpc_task *task, void *data) |
1da177e4 | 636 | { |
963d8fe5 | 637 | struct nlm_rqst *call = data; |
92737230 | 638 | struct nlm_block *block = call->a_block; |
1da177e4 | 639 | unsigned long timeout; |
1da177e4 LT |
640 | |
641 | dprintk("lockd: GRANT_MSG RPC callback\n"); | |
1da177e4 LT |
642 | |
643 | /* Technically, we should down the file semaphore here. Since we | |
644 | * move the block towards the head of the queue only, no harm | |
645 | * can be done, though. */ | |
646 | if (task->tk_status < 0) { | |
647 | /* RPC error: Re-insert for retransmission */ | |
648 | timeout = 10 * HZ; | |
1da177e4 LT |
649 | } else { |
650 | /* Call was successful, now wait for client callback */ | |
651 | timeout = 60 * HZ; | |
652 | } | |
653 | nlmsvc_insert_block(block, timeout); | |
654 | svc_wake_up(block->b_daemon); | |
5e1abf8c TM |
655 | } |
656 | ||
ec535ce1 | 657 | static void nlmsvc_grant_release(void *data) |
5e1abf8c | 658 | { |
6041b791 TM |
659 | struct nlm_rqst *call = data; |
660 | ||
661 | nlmsvc_release_block(call->a_block); | |
1da177e4 LT |
662 | } |
663 | ||
963d8fe5 TM |
664 | static const struct rpc_call_ops nlmsvc_grant_ops = { |
665 | .rpc_call_done = nlmsvc_grant_callback, | |
5e1abf8c | 666 | .rpc_release = nlmsvc_grant_release, |
963d8fe5 TM |
667 | }; |
668 | ||
1da177e4 LT |
669 | /* |
670 | * We received a GRANT_RES callback. Try to find the corresponding | |
671 | * block. | |
672 | */ | |
673 | void | |
e8c5c045 | 674 | nlmsvc_grant_reply(struct nlm_cookie *cookie, __be32 status) |
1da177e4 LT |
675 | { |
676 | struct nlm_block *block; | |
1da177e4 | 677 | |
39be4502 OK |
678 | dprintk("grant_reply: looking for cookie %x, s=%d \n", |
679 | *(unsigned int *)(cookie->data), status); | |
680 | if (!(block = nlmsvc_find_block(cookie))) | |
1da177e4 | 681 | return; |
1da177e4 | 682 | |
f232142c | 683 | if (block) { |
e8c5c045 | 684 | if (status == nlm_lck_denied_grace_period) { |
1da177e4 LT |
685 | /* Try again in a couple of seconds */ |
686 | nlmsvc_insert_block(block, 10 * HZ); | |
1da177e4 LT |
687 | } else { |
688 | /* Lock is now held by client, or has been rejected. | |
689 | * In both cases, the block should be removed. */ | |
6849c0ca | 690 | nlmsvc_unlink_block(block); |
1da177e4 LT |
691 | } |
692 | } | |
6849c0ca | 693 | nlmsvc_release_block(block); |
1da177e4 LT |
694 | } |
695 | ||
696 | /* | |
697 | * Retry all blocked locks that have been notified. This is where lockd | |
698 | * picks up locks that can be granted, or grant notifications that must | |
699 | * be retransmitted. | |
700 | */ | |
701 | unsigned long | |
702 | nlmsvc_retry_blocked(void) | |
703 | { | |
68a2d76c OK |
704 | unsigned long timeout = MAX_SCHEDULE_TIMEOUT; |
705 | struct nlm_block *block; | |
706 | ||
707 | while (!list_empty(&nlm_blocked)) { | |
708 | block = list_entry(nlm_blocked.next, struct nlm_block, b_list); | |
1da177e4 | 709 | |
1da177e4 LT |
710 | if (block->b_when == NLM_NEVER) |
711 | break; | |
68a2d76c OK |
712 | if (time_after(block->b_when,jiffies)) { |
713 | timeout = block->b_when - jiffies; | |
1da177e4 | 714 | break; |
68a2d76c OK |
715 | } |
716 | ||
f3d43c76 BF |
717 | dprintk("nlmsvc_retry_blocked(%p, when=%ld)\n", |
718 | block, block->b_when); | |
6849c0ca | 719 | kref_get(&block->b_count); |
f3d43c76 | 720 | nlmsvc_grant_blocked(block); |
6849c0ca | 721 | nlmsvc_release_block(block); |
1da177e4 LT |
722 | } |
723 | ||
68a2d76c | 724 | return timeout; |
1da177e4 | 725 | } |