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 | ||
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 | |
560de0e6 | 183 | nlm_get_host(host); |
92737230 TM |
184 | call = nlm_alloc_call(host); |
185 | if (call == NULL) | |
186 | return NULL; | |
187 | ||
1da177e4 | 188 | /* Allocate memory for block, and initialize arguments */ |
92737230 TM |
189 | block = kzalloc(sizeof(*block), GFP_KERNEL); |
190 | if (block == NULL) | |
1da177e4 | 191 | goto failed; |
6849c0ca | 192 | kref_init(&block->b_count); |
68a2d76c OK |
193 | INIT_LIST_HEAD(&block->b_list); |
194 | INIT_LIST_HEAD(&block->b_flist); | |
1da177e4 | 195 | |
92737230 | 196 | if (!nlmsvc_setgrantargs(call, lock)) |
1da177e4 LT |
197 | goto failed_free; |
198 | ||
199 | /* Set notifier function for VFS, and init args */ | |
92737230 TM |
200 | call->a_args.lock.fl.fl_flags |= FL_SLEEP; |
201 | call->a_args.lock.fl.fl_lmops = &nlmsvc_lock_operations; | |
39be4502 | 202 | nlmclnt_next_cookie(&call->a_args.cookie); |
1da177e4 LT |
203 | |
204 | dprintk("lockd: created block %p...\n", block); | |
205 | ||
206 | /* Create and initialize the block */ | |
207 | block->b_daemon = rqstp->rq_server; | |
208 | block->b_host = host; | |
209 | block->b_file = file; | |
5ea0d750 | 210 | block->b_fl = NULL; |
d9f6eb75 | 211 | file->f_count++; |
1da177e4 LT |
212 | |
213 | /* Add to file's list of blocks */ | |
68a2d76c | 214 | list_add(&block->b_flist, &file->f_blocks); |
1da177e4 LT |
215 | |
216 | /* Set up RPC arguments for callback */ | |
92737230 | 217 | block->b_call = call; |
1da177e4 | 218 | call->a_flags = RPC_TASK_ASYNC; |
92737230 | 219 | call->a_block = block; |
1da177e4 LT |
220 | |
221 | return block; | |
222 | ||
223 | failed_free: | |
224 | kfree(block); | |
225 | failed: | |
92737230 | 226 | nlm_release_call(call); |
1da177e4 LT |
227 | return NULL; |
228 | } | |
229 | ||
230 | /* | |
3c61eecb | 231 | * Delete a block. |
1da177e4 LT |
232 | * It is the caller's responsibility to check whether the file |
233 | * can be closed hereafter. | |
234 | */ | |
6849c0ca | 235 | static int nlmsvc_unlink_block(struct nlm_block *block) |
1da177e4 | 236 | { |
09c7938c | 237 | int status; |
6849c0ca | 238 | dprintk("lockd: unlinking block %p...\n", block); |
1da177e4 LT |
239 | |
240 | /* Remove block from list */ | |
92737230 | 241 | status = posix_unblock_lock(block->b_file->f_file, &block->b_call->a_args.lock.fl); |
1da177e4 | 242 | nlmsvc_remove_block(block); |
6849c0ca TM |
243 | return status; |
244 | } | |
1da177e4 | 245 | |
6849c0ca TM |
246 | static void nlmsvc_free_block(struct kref *kref) |
247 | { | |
248 | struct nlm_block *block = container_of(kref, struct nlm_block, b_count); | |
249 | struct nlm_file *file = block->b_file; | |
6849c0ca TM |
250 | |
251 | dprintk("lockd: freeing block %p...\n", block); | |
1da177e4 LT |
252 | |
253 | /* Remove block from file's list of blocks */ | |
89e63ef6 | 254 | mutex_lock(&file->f_mutex); |
68a2d76c | 255 | list_del_init(&block->b_flist); |
89e63ef6 | 256 | mutex_unlock(&file->f_mutex); |
1da177e4 | 257 | |
92737230 TM |
258 | nlmsvc_freegrantargs(block->b_call); |
259 | nlm_release_call(block->b_call); | |
d9f6eb75 | 260 | nlm_release_file(block->b_file); |
0e4ac9d9 | 261 | kfree(block->b_fl); |
1da177e4 | 262 | kfree(block); |
6849c0ca TM |
263 | } |
264 | ||
265 | static void nlmsvc_release_block(struct nlm_block *block) | |
266 | { | |
267 | if (block != NULL) | |
268 | kref_put(&block->b_count, nlmsvc_free_block); | |
1da177e4 LT |
269 | } |
270 | ||
f2af793d OK |
271 | /* |
272 | * Loop over all blocks and delete blocks held by | |
273 | * a matching host. | |
274 | */ | |
275 | void nlmsvc_traverse_blocks(struct nlm_host *host, | |
276 | struct nlm_file *file, | |
277 | nlm_host_match_fn_t match) | |
d9f6eb75 | 278 | { |
68a2d76c | 279 | struct nlm_block *block, *next; |
d9f6eb75 TM |
280 | |
281 | restart: | |
89e63ef6 | 282 | mutex_lock(&file->f_mutex); |
68a2d76c | 283 | list_for_each_entry_safe(block, next, &file->f_blocks, b_flist) { |
f2af793d | 284 | if (!match(block->b_host, host)) |
d9f6eb75 | 285 | continue; |
68a2d76c OK |
286 | /* Do not destroy blocks that are not on |
287 | * the global retry list - why? */ | |
288 | if (list_empty(&block->b_list)) | |
d9f6eb75 TM |
289 | continue; |
290 | kref_get(&block->b_count); | |
89e63ef6 | 291 | mutex_unlock(&file->f_mutex); |
d9f6eb75 TM |
292 | nlmsvc_unlink_block(block); |
293 | nlmsvc_release_block(block); | |
294 | goto restart; | |
295 | } | |
89e63ef6 | 296 | mutex_unlock(&file->f_mutex); |
d9f6eb75 TM |
297 | } |
298 | ||
5e1abf8c TM |
299 | /* |
300 | * Initialize arguments for GRANTED call. The nlm_rqst structure | |
301 | * has been cleared already. | |
302 | */ | |
303 | static int nlmsvc_setgrantargs(struct nlm_rqst *call, struct nlm_lock *lock) | |
304 | { | |
305 | locks_copy_lock(&call->a_args.lock.fl, &lock->fl); | |
306 | memcpy(&call->a_args.lock.fh, &lock->fh, sizeof(call->a_args.lock.fh)); | |
e9ff3990 | 307 | call->a_args.lock.caller = utsname()->nodename; |
5e1abf8c TM |
308 | call->a_args.lock.oh.len = lock->oh.len; |
309 | ||
310 | /* set default data area */ | |
311 | call->a_args.lock.oh.data = call->a_owner; | |
312 | call->a_args.lock.svid = lock->fl.fl_pid; | |
313 | ||
314 | if (lock->oh.len > NLMCLNT_OHSIZE) { | |
315 | void *data = kmalloc(lock->oh.len, GFP_KERNEL); | |
92737230 | 316 | if (!data) |
5e1abf8c | 317 | return 0; |
5e1abf8c TM |
318 | call->a_args.lock.oh.data = (u8 *) data; |
319 | } | |
320 | ||
321 | memcpy(call->a_args.lock.oh.data, lock->oh.data, lock->oh.len); | |
322 | return 1; | |
323 | } | |
324 | ||
325 | static void nlmsvc_freegrantargs(struct nlm_rqst *call) | |
326 | { | |
92737230 | 327 | if (call->a_args.lock.oh.data != call->a_owner) |
5e1abf8c | 328 | kfree(call->a_args.lock.oh.data); |
5e1abf8c TM |
329 | } |
330 | ||
2b36f412 ME |
331 | /* |
332 | * Deferred lock request handling for non-blocking lock | |
333 | */ | |
ca5c8cde | 334 | static __be32 |
2b36f412 ME |
335 | nlmsvc_defer_lock_rqst(struct svc_rqst *rqstp, struct nlm_block *block) |
336 | { | |
ca5c8cde | 337 | __be32 status = nlm_lck_denied_nolocks; |
2b36f412 ME |
338 | |
339 | block->b_flags |= B_QUEUED; | |
340 | ||
341 | nlmsvc_insert_block(block, NLM_TIMEOUT); | |
342 | ||
343 | block->b_cache_req = &rqstp->rq_chandle; | |
344 | if (rqstp->rq_chandle.defer) { | |
345 | block->b_deferred_req = | |
346 | rqstp->rq_chandle.defer(block->b_cache_req); | |
347 | if (block->b_deferred_req != NULL) | |
348 | status = nlm_drop_reply; | |
349 | } | |
350 | dprintk("lockd: nlmsvc_defer_lock_rqst block %p flags %d status %d\n", | |
ca5c8cde | 351 | block, block->b_flags, ntohl(status)); |
2b36f412 ME |
352 | |
353 | return status; | |
354 | } | |
355 | ||
1da177e4 LT |
356 | /* |
357 | * Attempt to establish a lock, and if it can't be granted, block it | |
358 | * if required. | |
359 | */ | |
52921e02 | 360 | __be32 |
1da177e4 | 361 | nlmsvc_lock(struct svc_rqst *rqstp, struct nlm_file *file, |
6cde4de8 JL |
362 | struct nlm_host *host, struct nlm_lock *lock, int wait, |
363 | struct nlm_cookie *cookie) | |
1da177e4 | 364 | { |
f8120480 | 365 | struct nlm_block *block = NULL; |
1da177e4 | 366 | int error; |
52921e02 | 367 | __be32 ret; |
1da177e4 LT |
368 | |
369 | dprintk("lockd: nlmsvc_lock(%s/%ld, ty=%d, pi=%d, %Ld-%Ld, bl=%d)\n", | |
225a719f JS |
370 | file->f_file->f_path.dentry->d_inode->i_sb->s_id, |
371 | file->f_file->f_path.dentry->d_inode->i_ino, | |
1da177e4 LT |
372 | lock->fl.fl_type, lock->fl.fl_pid, |
373 | (long long)lock->fl.fl_start, | |
374 | (long long)lock->fl.fl_end, | |
375 | wait); | |
376 | ||
1da177e4 | 377 | /* Lock file against concurrent access */ |
89e63ef6 | 378 | mutex_lock(&file->f_mutex); |
f8120480 ME |
379 | /* Get existing block (in case client is busy-waiting) |
380 | * or create new block | |
381 | */ | |
d9f6eb75 | 382 | block = nlmsvc_lookup_block(file, lock); |
09c7938c | 383 | if (block == NULL) { |
560de0e6 | 384 | block = nlmsvc_create_block(rqstp, host, file, 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; |
bde74e4b MS |
421 | goto out; |
422 | case FILE_LOCK_DEFERRED: | |
1a8322b2 ME |
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 | 437 | ret = nlm_lck_blocked; |
1da177e4 LT |
438 | |
439 | /* Append to list of blocked */ | |
f8120480 | 440 | nlmsvc_insert_block(block, NLM_NEVER); |
15dadef9 | 441 | out: |
89e63ef6 | 442 | mutex_unlock(&file->f_mutex); |
6849c0ca | 443 | nlmsvc_release_block(block); |
15dadef9 AA |
444 | dprintk("lockd: nlmsvc_lock returned %u\n", ret); |
445 | return ret; | |
1da177e4 LT |
446 | } |
447 | ||
448 | /* | |
449 | * Test for presence of a conflicting lock. | |
450 | */ | |
52921e02 | 451 | __be32 |
85f3f1b3 | 452 | nlmsvc_testlock(struct svc_rqst *rqstp, struct nlm_file *file, |
8f920d5e JL |
453 | struct nlm_host *host, struct nlm_lock *lock, |
454 | struct nlm_lock *conflock, struct nlm_cookie *cookie) | |
1da177e4 | 455 | { |
5ea0d750 ME |
456 | struct nlm_block *block = NULL; |
457 | int error; | |
458 | __be32 ret; | |
459 | ||
1da177e4 | 460 | dprintk("lockd: nlmsvc_testlock(%s/%ld, ty=%d, %Ld-%Ld)\n", |
225a719f JS |
461 | file->f_file->f_path.dentry->d_inode->i_sb->s_id, |
462 | file->f_file->f_path.dentry->d_inode->i_ino, | |
1da177e4 LT |
463 | lock->fl.fl_type, |
464 | (long long)lock->fl.fl_start, | |
465 | (long long)lock->fl.fl_end); | |
466 | ||
5ea0d750 ME |
467 | /* Get existing block (in case client is busy-waiting) */ |
468 | block = nlmsvc_lookup_block(file, lock); | |
469 | ||
470 | if (block == NULL) { | |
471 | struct file_lock *conf = kzalloc(sizeof(*conf), GFP_KERNEL); | |
472 | ||
473 | if (conf == NULL) | |
474 | return nlm_granted; | |
255129d1 | 475 | block = nlmsvc_create_block(rqstp, host, file, lock, cookie); |
5ea0d750 ME |
476 | if (block == NULL) { |
477 | kfree(conf); | |
478 | return nlm_granted; | |
479 | } | |
480 | block->b_fl = conf; | |
481 | } | |
482 | if (block->b_flags & B_QUEUED) { | |
483 | dprintk("lockd: nlmsvc_testlock deferred block %p flags %d fl %p\n", | |
484 | block, block->b_flags, block->b_fl); | |
485 | if (block->b_flags & B_TIMED_OUT) { | |
486 | nlmsvc_unlink_block(block); | |
29dbf546 OD |
487 | ret = nlm_lck_denied; |
488 | goto out; | |
5ea0d750 ME |
489 | } |
490 | if (block->b_flags & B_GOT_CALLBACK) { | |
54ca95eb | 491 | nlmsvc_unlink_block(block); |
5ea0d750 ME |
492 | if (block->b_fl != NULL |
493 | && block->b_fl->fl_type != F_UNLCK) { | |
494 | lock->fl = *block->b_fl; | |
495 | goto conf_lock; | |
29dbf546 | 496 | } else { |
29dbf546 OD |
497 | ret = nlm_granted; |
498 | goto out; | |
5ea0d750 ME |
499 | } |
500 | } | |
29dbf546 OD |
501 | ret = nlm_drop_reply; |
502 | goto out; | |
1da177e4 LT |
503 | } |
504 | ||
5ea0d750 | 505 | error = vfs_test_lock(file->f_file, &lock->fl); |
bde74e4b | 506 | if (error == FILE_LOCK_DEFERRED) { |
29dbf546 OD |
507 | ret = nlmsvc_defer_lock_rqst(rqstp, block); |
508 | goto out; | |
509 | } | |
5ea0d750 ME |
510 | if (error) { |
511 | ret = nlm_lck_denied_nolocks; | |
512 | goto out; | |
513 | } | |
514 | if (lock->fl.fl_type == F_UNLCK) { | |
515 | ret = nlm_granted; | |
516 | goto out; | |
517 | } | |
518 | ||
519 | conf_lock: | |
520 | dprintk("lockd: conflicting lock(ty=%d, %Ld-%Ld)\n", | |
521 | lock->fl.fl_type, (long long)lock->fl.fl_start, | |
522 | (long long)lock->fl.fl_end); | |
523 | conflock->caller = "somehost"; /* FIXME */ | |
524 | conflock->len = strlen(conflock->caller); | |
525 | conflock->oh.len = 0; /* don't return OH info */ | |
526 | conflock->svid = lock->fl.fl_pid; | |
527 | conflock->fl.fl_type = lock->fl.fl_type; | |
528 | conflock->fl.fl_start = lock->fl.fl_start; | |
529 | conflock->fl.fl_end = lock->fl.fl_end; | |
530 | ret = nlm_lck_denied; | |
531 | out: | |
532 | if (block) | |
533 | nlmsvc_release_block(block); | |
534 | return ret; | |
1da177e4 LT |
535 | } |
536 | ||
537 | /* | |
538 | * Remove a lock. | |
539 | * This implies a CANCEL call: We send a GRANT_MSG, the client replies | |
540 | * with a GRANT_RES call which gets lost, and calls UNLOCK immediately | |
541 | * afterwards. In this case the block will still be there, and hence | |
542 | * must be removed. | |
543 | */ | |
52921e02 | 544 | __be32 |
1da177e4 LT |
545 | nlmsvc_unlock(struct nlm_file *file, struct nlm_lock *lock) |
546 | { | |
547 | int error; | |
548 | ||
549 | dprintk("lockd: nlmsvc_unlock(%s/%ld, pi=%d, %Ld-%Ld)\n", | |
225a719f JS |
550 | file->f_file->f_path.dentry->d_inode->i_sb->s_id, |
551 | file->f_file->f_path.dentry->d_inode->i_ino, | |
1da177e4 LT |
552 | lock->fl.fl_pid, |
553 | (long long)lock->fl.fl_start, | |
554 | (long long)lock->fl.fl_end); | |
555 | ||
556 | /* First, cancel any lock that might be there */ | |
557 | nlmsvc_cancel_blocked(file, lock); | |
558 | ||
559 | lock->fl.fl_type = F_UNLCK; | |
1a8322b2 | 560 | error = vfs_lock_file(file->f_file, F_SETLK, &lock->fl, NULL); |
1da177e4 LT |
561 | |
562 | return (error < 0)? nlm_lck_denied_nolocks : nlm_granted; | |
563 | } | |
564 | ||
565 | /* | |
566 | * Cancel a previously blocked request. | |
567 | * | |
568 | * A cancel request always overrides any grant that may currently | |
569 | * be in progress. | |
570 | * The calling procedure must check whether the file can be closed. | |
571 | */ | |
52921e02 | 572 | __be32 |
1da177e4 LT |
573 | nlmsvc_cancel_blocked(struct nlm_file *file, struct nlm_lock *lock) |
574 | { | |
575 | struct nlm_block *block; | |
64a318ee | 576 | int status = 0; |
1da177e4 LT |
577 | |
578 | dprintk("lockd: nlmsvc_cancel(%s/%ld, pi=%d, %Ld-%Ld)\n", | |
225a719f JS |
579 | file->f_file->f_path.dentry->d_inode->i_sb->s_id, |
580 | file->f_file->f_path.dentry->d_inode->i_ino, | |
1da177e4 LT |
581 | lock->fl.fl_pid, |
582 | (long long)lock->fl.fl_start, | |
583 | (long long)lock->fl.fl_end); | |
584 | ||
89e63ef6 | 585 | mutex_lock(&file->f_mutex); |
d9f6eb75 | 586 | block = nlmsvc_lookup_block(file, lock); |
89e63ef6 | 587 | mutex_unlock(&file->f_mutex); |
d9f6eb75 | 588 | if (block != NULL) { |
1a8322b2 ME |
589 | vfs_cancel_lock(block->b_file->f_file, |
590 | &block->b_call->a_args.lock.fl); | |
6849c0ca TM |
591 | status = nlmsvc_unlink_block(block); |
592 | nlmsvc_release_block(block); | |
593 | } | |
64a318ee | 594 | return status ? nlm_lck_denied : nlm_granted; |
1da177e4 LT |
595 | } |
596 | ||
0e4ac9d9 ME |
597 | /* |
598 | * This is a callback from the filesystem for VFS file lock requests. | |
599 | * It will be used if fl_grant is defined and the filesystem can not | |
600 | * respond to the request immediately. | |
601 | * For GETLK request it will copy the reply to the nlm_block. | |
602 | * For SETLK or SETLKW request it will get the local posix lock. | |
603 | * In all cases it will move the block to the head of nlm_blocked q where | |
604 | * nlmsvc_retry_blocked() can send back a reply for SETLKW or revisit the | |
605 | * deferred rpc for GETLK and SETLK. | |
606 | */ | |
607 | static void | |
608 | nlmsvc_update_deferred_block(struct nlm_block *block, struct file_lock *conf, | |
609 | int result) | |
610 | { | |
611 | block->b_flags |= B_GOT_CALLBACK; | |
612 | if (result == 0) | |
613 | block->b_granted = 1; | |
614 | else | |
615 | block->b_flags |= B_TIMED_OUT; | |
616 | if (conf) { | |
0e4ac9d9 | 617 | if (block->b_fl) |
1a747ee0 | 618 | __locks_copy_lock(block->b_fl, conf); |
0e4ac9d9 ME |
619 | } |
620 | } | |
621 | ||
622 | static int nlmsvc_grant_deferred(struct file_lock *fl, struct file_lock *conf, | |
623 | int result) | |
624 | { | |
625 | struct nlm_block *block; | |
626 | int rc = -ENOENT; | |
627 | ||
628 | lock_kernel(); | |
629 | list_for_each_entry(block, &nlm_blocked, b_list) { | |
630 | if (nlm_compare_locks(&block->b_call->a_args.lock.fl, fl)) { | |
631 | dprintk("lockd: nlmsvc_notify_blocked block %p flags %d\n", | |
632 | block, block->b_flags); | |
633 | if (block->b_flags & B_QUEUED) { | |
634 | if (block->b_flags & B_TIMED_OUT) { | |
635 | rc = -ENOLCK; | |
636 | break; | |
637 | } | |
638 | nlmsvc_update_deferred_block(block, conf, result); | |
639 | } else if (result == 0) | |
640 | block->b_granted = 1; | |
641 | ||
642 | nlmsvc_insert_block(block, 0); | |
643 | svc_wake_up(block->b_daemon); | |
644 | rc = 0; | |
645 | break; | |
646 | } | |
647 | } | |
648 | unlock_kernel(); | |
649 | if (rc == -ENOENT) | |
650 | printk(KERN_WARNING "lockd: grant for unknown block\n"); | |
651 | return rc; | |
652 | } | |
653 | ||
1da177e4 LT |
654 | /* |
655 | * Unblock a blocked lock request. This is a callback invoked from the | |
656 | * VFS layer when a lock on which we blocked is removed. | |
657 | * | |
658 | * This function doesn't grant the blocked lock instantly, but rather moves | |
659 | * the block to the head of nlm_blocked where it can be picked up by lockd. | |
660 | */ | |
661 | static void | |
662 | nlmsvc_notify_blocked(struct file_lock *fl) | |
663 | { | |
68a2d76c | 664 | struct nlm_block *block; |
1da177e4 LT |
665 | |
666 | dprintk("lockd: VFS unblock notification for block %p\n", fl); | |
68a2d76c | 667 | list_for_each_entry(block, &nlm_blocked, b_list) { |
92737230 | 668 | if (nlm_compare_locks(&block->b_call->a_args.lock.fl, fl)) { |
1da177e4 LT |
669 | nlmsvc_insert_block(block, 0); |
670 | svc_wake_up(block->b_daemon); | |
671 | return; | |
672 | } | |
673 | } | |
674 | ||
675 | printk(KERN_WARNING "lockd: notification for unknown block!\n"); | |
676 | } | |
677 | ||
678 | static int nlmsvc_same_owner(struct file_lock *fl1, struct file_lock *fl2) | |
679 | { | |
680 | return fl1->fl_owner == fl2->fl_owner && fl1->fl_pid == fl2->fl_pid; | |
681 | } | |
682 | ||
683 | struct lock_manager_operations nlmsvc_lock_operations = { | |
684 | .fl_compare_owner = nlmsvc_same_owner, | |
685 | .fl_notify = nlmsvc_notify_blocked, | |
0e4ac9d9 | 686 | .fl_grant = nlmsvc_grant_deferred, |
1da177e4 LT |
687 | }; |
688 | ||
689 | /* | |
690 | * Try to claim a lock that was previously blocked. | |
691 | * | |
692 | * Note that we use both the RPC_GRANTED_MSG call _and_ an async | |
693 | * RPC thread when notifying the client. This seems like overkill... | |
694 | * Here's why: | |
695 | * - we don't want to use a synchronous RPC thread, otherwise | |
696 | * we might find ourselves hanging on a dead portmapper. | |
697 | * - Some lockd implementations (e.g. HP) don't react to | |
698 | * RPC_GRANTED calls; they seem to insist on RPC_GRANTED_MSG calls. | |
699 | */ | |
700 | static void | |
701 | nlmsvc_grant_blocked(struct nlm_block *block) | |
702 | { | |
703 | struct nlm_file *file = block->b_file; | |
92737230 | 704 | struct nlm_lock *lock = &block->b_call->a_args.lock; |
1da177e4 LT |
705 | int error; |
706 | ||
707 | dprintk("lockd: grant blocked lock %p\n", block); | |
708 | ||
0e4ac9d9 ME |
709 | kref_get(&block->b_count); |
710 | ||
1da177e4 | 711 | /* Unlink block request from list */ |
6849c0ca | 712 | nlmsvc_unlink_block(block); |
1da177e4 LT |
713 | |
714 | /* If b_granted is true this means we've been here before. | |
715 | * Just retry the grant callback, possibly refreshing the RPC | |
716 | * binding */ | |
717 | if (block->b_granted) { | |
718 | nlm_rebind_host(block->b_host); | |
719 | goto callback; | |
720 | } | |
721 | ||
722 | /* Try the lock operation again */ | |
09c7938c | 723 | lock->fl.fl_flags |= FL_SLEEP; |
1a8322b2 | 724 | error = vfs_lock_file(file->f_file, F_SETLK, &lock->fl, NULL); |
09c7938c TM |
725 | lock->fl.fl_flags &= ~FL_SLEEP; |
726 | ||
5de0e502 AA |
727 | switch (error) { |
728 | case 0: | |
729 | break; | |
bde74e4b | 730 | case FILE_LOCK_DEFERRED: |
1a8322b2 | 731 | dprintk("lockd: lock still blocked error %d\n", error); |
1da177e4 | 732 | nlmsvc_insert_block(block, NLM_NEVER); |
0e4ac9d9 | 733 | nlmsvc_release_block(block); |
d9f6eb75 | 734 | return; |
5de0e502 | 735 | default: |
1da177e4 | 736 | printk(KERN_WARNING "lockd: unexpected error %d in %s!\n", |
8e24eea7 | 737 | -error, __func__); |
1da177e4 | 738 | nlmsvc_insert_block(block, 10 * HZ); |
0e4ac9d9 | 739 | nlmsvc_release_block(block); |
d9f6eb75 | 740 | return; |
1da177e4 LT |
741 | } |
742 | ||
743 | callback: | |
744 | /* Lock was granted by VFS. */ | |
745 | dprintk("lockd: GRANTing blocked lock.\n"); | |
746 | block->b_granted = 1; | |
1da177e4 | 747 | |
9706501e JL |
748 | /* keep block on the list, but don't reattempt until the RPC |
749 | * completes or the submission fails | |
750 | */ | |
751 | nlmsvc_insert_block(block, NLM_NEVER); | |
1da177e4 | 752 | |
9706501e JL |
753 | /* Call the client -- use a soft RPC task since nlmsvc_retry_blocked |
754 | * will queue up a new one if this one times out | |
755 | */ | |
756 | error = nlm_async_call(block->b_call, NLMPROC_GRANTED_MSG, | |
757 | &nlmsvc_grant_ops); | |
758 | ||
759 | /* RPC submission failed, wait a bit and retry */ | |
760 | if (error < 0) | |
761 | nlmsvc_insert_block(block, 10 * HZ); | |
1da177e4 LT |
762 | } |
763 | ||
764 | /* | |
765 | * This is the callback from the RPC layer when the NLM_GRANTED_MSG | |
766 | * RPC call has succeeded or timed out. | |
767 | * Like all RPC callbacks, it is invoked by the rpciod process, so it | |
768 | * better not sleep. Therefore, we put the blocked lock on the nlm_blocked | |
769 | * chain once more in order to have it removed by lockd itself (which can | |
770 | * then sleep on the file semaphore without disrupting e.g. the nfs client). | |
771 | */ | |
963d8fe5 | 772 | static void nlmsvc_grant_callback(struct rpc_task *task, void *data) |
1da177e4 | 773 | { |
963d8fe5 | 774 | struct nlm_rqst *call = data; |
92737230 | 775 | struct nlm_block *block = call->a_block; |
1da177e4 | 776 | unsigned long timeout; |
1da177e4 LT |
777 | |
778 | dprintk("lockd: GRANT_MSG RPC callback\n"); | |
1da177e4 | 779 | |
a86dc496 | 780 | lock_kernel(); |
c64e80d5 JL |
781 | /* if the block is not on a list at this point then it has |
782 | * been invalidated. Don't try to requeue it. | |
783 | * | |
784 | * FIXME: it's possible that the block is removed from the list | |
785 | * after this check but before the nlmsvc_insert_block. In that | |
786 | * case it will be added back. Perhaps we need better locking | |
787 | * for nlm_blocked? | |
788 | */ | |
789 | if (list_empty(&block->b_list)) | |
a86dc496 | 790 | goto out; |
c64e80d5 | 791 | |
1da177e4 LT |
792 | /* Technically, we should down the file semaphore here. Since we |
793 | * move the block towards the head of the queue only, no harm | |
794 | * can be done, though. */ | |
795 | if (task->tk_status < 0) { | |
796 | /* RPC error: Re-insert for retransmission */ | |
797 | timeout = 10 * HZ; | |
1da177e4 LT |
798 | } else { |
799 | /* Call was successful, now wait for client callback */ | |
800 | timeout = 60 * HZ; | |
801 | } | |
802 | nlmsvc_insert_block(block, timeout); | |
803 | svc_wake_up(block->b_daemon); | |
a86dc496 TM |
804 | out: |
805 | unlock_kernel(); | |
5e1abf8c TM |
806 | } |
807 | ||
ec535ce1 | 808 | static void nlmsvc_grant_release(void *data) |
5e1abf8c | 809 | { |
6041b791 TM |
810 | struct nlm_rqst *call = data; |
811 | ||
a86dc496 | 812 | lock_kernel(); |
6041b791 | 813 | nlmsvc_release_block(call->a_block); |
a86dc496 | 814 | unlock_kernel(); |
1da177e4 LT |
815 | } |
816 | ||
963d8fe5 TM |
817 | static const struct rpc_call_ops nlmsvc_grant_ops = { |
818 | .rpc_call_done = nlmsvc_grant_callback, | |
5e1abf8c | 819 | .rpc_release = nlmsvc_grant_release, |
963d8fe5 TM |
820 | }; |
821 | ||
1da177e4 LT |
822 | /* |
823 | * We received a GRANT_RES callback. Try to find the corresponding | |
824 | * block. | |
825 | */ | |
826 | void | |
e8c5c045 | 827 | nlmsvc_grant_reply(struct nlm_cookie *cookie, __be32 status) |
1da177e4 LT |
828 | { |
829 | struct nlm_block *block; | |
1da177e4 | 830 | |
39be4502 OK |
831 | dprintk("grant_reply: looking for cookie %x, s=%d \n", |
832 | *(unsigned int *)(cookie->data), status); | |
833 | if (!(block = nlmsvc_find_block(cookie))) | |
1da177e4 | 834 | return; |
1da177e4 | 835 | |
f232142c | 836 | if (block) { |
e8c5c045 | 837 | if (status == nlm_lck_denied_grace_period) { |
1da177e4 LT |
838 | /* Try again in a couple of seconds */ |
839 | nlmsvc_insert_block(block, 10 * HZ); | |
1da177e4 LT |
840 | } else { |
841 | /* Lock is now held by client, or has been rejected. | |
842 | * In both cases, the block should be removed. */ | |
6849c0ca | 843 | nlmsvc_unlink_block(block); |
1da177e4 LT |
844 | } |
845 | } | |
6849c0ca | 846 | nlmsvc_release_block(block); |
1da177e4 LT |
847 | } |
848 | ||
0e4ac9d9 ME |
849 | /* Helper function to handle retry of a deferred block. |
850 | * If it is a blocking lock, call grant_blocked. | |
851 | * For a non-blocking lock or test lock, revisit the request. | |
852 | */ | |
853 | static void | |
854 | retry_deferred_block(struct nlm_block *block) | |
855 | { | |
856 | if (!(block->b_flags & B_GOT_CALLBACK)) | |
857 | block->b_flags |= B_TIMED_OUT; | |
858 | nlmsvc_insert_block(block, NLM_TIMEOUT); | |
859 | dprintk("revisit block %p flags %d\n", block, block->b_flags); | |
860 | if (block->b_deferred_req) { | |
861 | block->b_deferred_req->revisit(block->b_deferred_req, 0); | |
862 | block->b_deferred_req = NULL; | |
863 | } | |
864 | } | |
865 | ||
1da177e4 LT |
866 | /* |
867 | * Retry all blocked locks that have been notified. This is where lockd | |
868 | * picks up locks that can be granted, or grant notifications that must | |
869 | * be retransmitted. | |
870 | */ | |
871 | unsigned long | |
872 | nlmsvc_retry_blocked(void) | |
873 | { | |
68a2d76c OK |
874 | unsigned long timeout = MAX_SCHEDULE_TIMEOUT; |
875 | struct nlm_block *block; | |
876 | ||
d751a7cd | 877 | while (!list_empty(&nlm_blocked) && !kthread_should_stop()) { |
68a2d76c | 878 | block = list_entry(nlm_blocked.next, struct nlm_block, b_list); |
1da177e4 | 879 | |
1da177e4 LT |
880 | if (block->b_when == NLM_NEVER) |
881 | break; | |
6d7bbbba | 882 | if (time_after(block->b_when, jiffies)) { |
68a2d76c | 883 | timeout = block->b_when - jiffies; |
1da177e4 | 884 | break; |
68a2d76c OK |
885 | } |
886 | ||
f3d43c76 BF |
887 | dprintk("nlmsvc_retry_blocked(%p, when=%ld)\n", |
888 | block, block->b_when); | |
0e4ac9d9 ME |
889 | if (block->b_flags & B_QUEUED) { |
890 | dprintk("nlmsvc_retry_blocked delete block (%p, granted=%d, flags=%d)\n", | |
891 | block, block->b_granted, block->b_flags); | |
892 | retry_deferred_block(block); | |
893 | } else | |
894 | nlmsvc_grant_blocked(block); | |
1da177e4 LT |
895 | } |
896 | ||
68a2d76c | 897 | return timeout; |
1da177e4 | 898 | } |