Commit | Line | Data |
---|---|---|
b2441318 | 1 | // SPDX-License-Identifier: GPL-2.0 |
1da177e4 LT |
2 | /* |
3 | * linux/fs/lockd/svclock.c | |
4 | * | |
5 | * Handling of server-side locks, mostly of the blocked variety. | |
6 | * This is the ugliest part of lockd because we tread on very thin ice. | |
7 | * GRANT and CANCEL calls may get stuck, meet in mid-flight, etc. | |
8 | * IMNSHO introducing the grant callback into the NLM protocol was one | |
9 | * of the worst ideas Sun ever had. Except maybe for the idea of doing | |
10 | * NFS file locking at all. | |
11 | * | |
12 | * I'm trying hard to avoid race conditions by protecting most accesses | |
13 | * to a file's list of blocked locks through a semaphore. The global | |
14 | * list of blocked locks is not protected in this fashion however. | |
15 | * Therefore, some functions (such as the RPC callback for the async grant | |
16 | * call) move blocked locks towards the head of the list *while some other | |
17 | * process might be traversing it*. This should not be a problem in | |
18 | * practice, because this will only cause functions traversing the list | |
19 | * to visit some blocks twice. | |
20 | * | |
21 | * Copyright (C) 1996, Olaf Kirch <okir@monad.swb.de> | |
22 | */ | |
23 | ||
1da177e4 | 24 | #include <linux/types.h> |
5a0e3ad6 | 25 | #include <linux/slab.h> |
1da177e4 LT |
26 | #include <linux/errno.h> |
27 | #include <linux/kernel.h> | |
28 | #include <linux/sched.h> | |
1da177e4 | 29 | #include <linux/sunrpc/clnt.h> |
5ccb0066 | 30 | #include <linux/sunrpc/svc_xprt.h> |
1da177e4 LT |
31 | #include <linux/lockd/nlm.h> |
32 | #include <linux/lockd/lockd.h> | |
d751a7cd | 33 | #include <linux/kthread.h> |
1da177e4 LT |
34 | |
35 | #define NLMDBG_FACILITY NLMDBG_SVCLOCK | |
36 | ||
37 | #ifdef CONFIG_LOCKD_V4 | |
38 | #define nlm_deadlock nlm4_deadlock | |
39 | #else | |
40 | #define nlm_deadlock nlm_lck_denied | |
41 | #endif | |
42 | ||
6849c0ca | 43 | static void nlmsvc_release_block(struct nlm_block *block); |
1da177e4 | 44 | static void nlmsvc_insert_block(struct nlm_block *block, unsigned long); |
68a2d76c | 45 | static void nlmsvc_remove_block(struct nlm_block *block); |
963d8fe5 | 46 | |
5e1abf8c TM |
47 | static int nlmsvc_setgrantargs(struct nlm_rqst *call, struct nlm_lock *lock); |
48 | static void nlmsvc_freegrantargs(struct nlm_rqst *call); | |
963d8fe5 | 49 | static const struct rpc_call_ops nlmsvc_grant_ops; |
1da177e4 LT |
50 | |
51 | /* | |
52 | * The list of blocked locks to retry | |
53 | */ | |
68a2d76c | 54 | static LIST_HEAD(nlm_blocked); |
f904be9c | 55 | static DEFINE_SPINLOCK(nlm_blocked_lock); |
1da177e4 | 56 | |
10b89567 | 57 | #if IS_ENABLED(CONFIG_SUNRPC_DEBUG) |
ffa94db6 TM |
58 | static const char *nlmdbg_cookie2a(const struct nlm_cookie *cookie) |
59 | { | |
60 | /* | |
3c519914 JL |
61 | * We can get away with a static buffer because this is only called |
62 | * from lockd, which is single-threaded. | |
ffa94db6 TM |
63 | */ |
64 | static char buf[2*NLM_MAXCOOKIELEN+1]; | |
65 | unsigned int i, len = sizeof(buf); | |
66 | char *p = buf; | |
67 | ||
68 | len--; /* allow for trailing \0 */ | |
69 | if (len < 3) | |
70 | return "???"; | |
71 | for (i = 0 ; i < cookie->len ; i++) { | |
72 | if (len < 2) { | |
73 | strcpy(p-3, "..."); | |
74 | break; | |
75 | } | |
76 | sprintf(p, "%02x", cookie->data[i]); | |
77 | p += 2; | |
78 | len -= 2; | |
79 | } | |
80 | *p = '\0'; | |
81 | ||
82 | return buf; | |
83 | } | |
84 | #endif | |
85 | ||
1da177e4 LT |
86 | /* |
87 | * Insert a blocked lock into the global list | |
88 | */ | |
89 | static void | |
f904be9c | 90 | nlmsvc_insert_block_locked(struct nlm_block *block, unsigned long when) |
1da177e4 | 91 | { |
68a2d76c OK |
92 | struct nlm_block *b; |
93 | struct list_head *pos; | |
1da177e4 LT |
94 | |
95 | dprintk("lockd: nlmsvc_insert_block(%p, %ld)\n", block, when); | |
68a2d76c OK |
96 | if (list_empty(&block->b_list)) { |
97 | kref_get(&block->b_count); | |
98 | } else { | |
99 | list_del_init(&block->b_list); | |
100 | } | |
101 | ||
102 | pos = &nlm_blocked; | |
1da177e4 LT |
103 | if (when != NLM_NEVER) { |
104 | if ((when += jiffies) == NLM_NEVER) | |
105 | when ++; | |
68a2d76c OK |
106 | list_for_each(pos, &nlm_blocked) { |
107 | b = list_entry(pos, struct nlm_block, b_list); | |
108 | if (time_after(b->b_when,when) || b->b_when == NLM_NEVER) | |
109 | break; | |
110 | } | |
111 | /* On normal exit from the loop, pos == &nlm_blocked, | |
112 | * so we will be adding to the end of the list - good | |
113 | */ | |
114 | } | |
1da177e4 | 115 | |
68a2d76c | 116 | list_add_tail(&block->b_list, pos); |
1da177e4 | 117 | block->b_when = when; |
1da177e4 LT |
118 | } |
119 | ||
f904be9c BS |
120 | static void nlmsvc_insert_block(struct nlm_block *block, unsigned long when) |
121 | { | |
122 | spin_lock(&nlm_blocked_lock); | |
123 | nlmsvc_insert_block_locked(block, when); | |
124 | spin_unlock(&nlm_blocked_lock); | |
125 | } | |
126 | ||
1da177e4 LT |
127 | /* |
128 | * Remove a block from the global list | |
129 | */ | |
68a2d76c | 130 | static inline void |
1da177e4 LT |
131 | nlmsvc_remove_block(struct nlm_block *block) |
132 | { | |
68a2d76c | 133 | if (!list_empty(&block->b_list)) { |
f904be9c | 134 | spin_lock(&nlm_blocked_lock); |
68a2d76c | 135 | list_del_init(&block->b_list); |
f904be9c | 136 | spin_unlock(&nlm_blocked_lock); |
68a2d76c | 137 | nlmsvc_release_block(block); |
1da177e4 | 138 | } |
1da177e4 LT |
139 | } |
140 | ||
141 | /* | |
d9f6eb75 | 142 | * Find a block for a given lock |
1da177e4 LT |
143 | */ |
144 | static struct nlm_block * | |
d9f6eb75 | 145 | nlmsvc_lookup_block(struct nlm_file *file, struct nlm_lock *lock) |
1da177e4 | 146 | { |
68a2d76c | 147 | struct nlm_block *block; |
1da177e4 LT |
148 | struct file_lock *fl; |
149 | ||
150 | dprintk("lockd: nlmsvc_lookup_block f=%p pd=%d %Ld-%Ld ty=%d\n", | |
151 | file, lock->fl.fl_pid, | |
152 | (long long)lock->fl.fl_start, | |
153 | (long long)lock->fl.fl_end, lock->fl.fl_type); | |
68a2d76c | 154 | list_for_each_entry(block, &nlm_blocked, b_list) { |
92737230 | 155 | fl = &block->b_call->a_args.lock.fl; |
1da177e4 LT |
156 | dprintk("lockd: check f=%p pd=%d %Ld-%Ld ty=%d cookie=%s\n", |
157 | block->b_file, fl->fl_pid, | |
158 | (long long)fl->fl_start, | |
159 | (long long)fl->fl_end, fl->fl_type, | |
92737230 | 160 | nlmdbg_cookie2a(&block->b_call->a_args.cookie)); |
1da177e4 | 161 | if (block->b_file == file && nlm_compare_locks(fl, &lock->fl)) { |
6849c0ca | 162 | kref_get(&block->b_count); |
1da177e4 LT |
163 | return block; |
164 | } | |
165 | } | |
166 | ||
167 | return NULL; | |
168 | } | |
169 | ||
170 | static inline int nlm_cookie_match(struct nlm_cookie *a, struct nlm_cookie *b) | |
171 | { | |
6d7bbbba | 172 | if (a->len != b->len) |
1da177e4 | 173 | return 0; |
6d7bbbba | 174 | if (memcmp(a->data, b->data, a->len)) |
1da177e4 LT |
175 | return 0; |
176 | return 1; | |
177 | } | |
178 | ||
179 | /* | |
180 | * Find a block with a given NLM cookie. | |
181 | */ | |
182 | static inline struct nlm_block * | |
39be4502 | 183 | nlmsvc_find_block(struct nlm_cookie *cookie) |
1da177e4 LT |
184 | { |
185 | struct nlm_block *block; | |
186 | ||
68a2d76c | 187 | list_for_each_entry(block, &nlm_blocked, b_list) { |
39be4502 | 188 | if (nlm_cookie_match(&block->b_call->a_args.cookie,cookie)) |
68a2d76c | 189 | goto found; |
1da177e4 LT |
190 | } |
191 | ||
68a2d76c OK |
192 | return NULL; |
193 | ||
194 | found: | |
39be4502 | 195 | dprintk("nlmsvc_find_block(%s): block=%p\n", nlmdbg_cookie2a(cookie), block); |
68a2d76c | 196 | kref_get(&block->b_count); |
1da177e4 LT |
197 | return block; |
198 | } | |
199 | ||
200 | /* | |
201 | * Create a block and initialize it. | |
202 | * | |
203 | * Note: we explicitly set the cookie of the grant reply to that of | |
204 | * the blocked lock request. The spec explicitly mentions that the client | |
205 | * should _not_ rely on the callback containing the same cookie as the | |
206 | * request, but (as I found out later) that's because some implementations | |
207 | * do just this. Never mind the standards comittees, they support our | |
208 | * logging industries. | |
39be4502 OK |
209 | * |
210 | * 10 years later: I hope we can safely ignore these old and broken | |
211 | * clients by now. Let's fix this so we can uniquely identify an incoming | |
212 | * GRANTED_RES message by cookie, without having to rely on the client's IP | |
213 | * address. --okir | |
1da177e4 | 214 | */ |
255129d1 TM |
215 | static struct nlm_block * |
216 | nlmsvc_create_block(struct svc_rqst *rqstp, struct nlm_host *host, | |
217 | struct nlm_file *file, struct nlm_lock *lock, | |
218 | struct nlm_cookie *cookie) | |
1da177e4 LT |
219 | { |
220 | struct nlm_block *block; | |
92737230 | 221 | struct nlm_rqst *call = NULL; |
1da177e4 | 222 | |
92737230 TM |
223 | call = nlm_alloc_call(host); |
224 | if (call == NULL) | |
225 | return NULL; | |
226 | ||
1da177e4 | 227 | /* Allocate memory for block, and initialize arguments */ |
92737230 TM |
228 | block = kzalloc(sizeof(*block), GFP_KERNEL); |
229 | if (block == NULL) | |
1da177e4 | 230 | goto failed; |
6849c0ca | 231 | kref_init(&block->b_count); |
68a2d76c OK |
232 | INIT_LIST_HEAD(&block->b_list); |
233 | INIT_LIST_HEAD(&block->b_flist); | |
1da177e4 | 234 | |
92737230 | 235 | if (!nlmsvc_setgrantargs(call, lock)) |
1da177e4 LT |
236 | goto failed_free; |
237 | ||
238 | /* Set notifier function for VFS, and init args */ | |
92737230 TM |
239 | call->a_args.lock.fl.fl_flags |= FL_SLEEP; |
240 | call->a_args.lock.fl.fl_lmops = &nlmsvc_lock_operations; | |
39be4502 | 241 | nlmclnt_next_cookie(&call->a_args.cookie); |
1da177e4 LT |
242 | |
243 | dprintk("lockd: created block %p...\n", block); | |
244 | ||
245 | /* Create and initialize the block */ | |
246 | block->b_daemon = rqstp->rq_server; | |
247 | block->b_host = host; | |
248 | block->b_file = file; | |
d9f6eb75 | 249 | file->f_count++; |
1da177e4 LT |
250 | |
251 | /* Add to file's list of blocks */ | |
68a2d76c | 252 | list_add(&block->b_flist, &file->f_blocks); |
1da177e4 LT |
253 | |
254 | /* Set up RPC arguments for callback */ | |
92737230 | 255 | block->b_call = call; |
1da177e4 | 256 | call->a_flags = RPC_TASK_ASYNC; |
92737230 | 257 | call->a_block = block; |
1da177e4 LT |
258 | |
259 | return block; | |
260 | ||
261 | failed_free: | |
262 | kfree(block); | |
263 | failed: | |
7db836d4 | 264 | nlmsvc_release_call(call); |
1da177e4 LT |
265 | return NULL; |
266 | } | |
267 | ||
268 | /* | |
3c61eecb | 269 | * Delete a block. |
1da177e4 LT |
270 | * It is the caller's responsibility to check whether the file |
271 | * can be closed hereafter. | |
272 | */ | |
6849c0ca | 273 | static int nlmsvc_unlink_block(struct nlm_block *block) |
1da177e4 | 274 | { |
09c7938c | 275 | int status; |
6849c0ca | 276 | dprintk("lockd: unlinking block %p...\n", block); |
1da177e4 LT |
277 | |
278 | /* Remove block from list */ | |
f891a29f | 279 | status = posix_unblock_lock(&block->b_call->a_args.lock.fl); |
1da177e4 | 280 | nlmsvc_remove_block(block); |
6849c0ca TM |
281 | return status; |
282 | } | |
1da177e4 | 283 | |
6849c0ca TM |
284 | static void nlmsvc_free_block(struct kref *kref) |
285 | { | |
286 | struct nlm_block *block = container_of(kref, struct nlm_block, b_count); | |
287 | struct nlm_file *file = block->b_file; | |
6849c0ca TM |
288 | |
289 | dprintk("lockd: freeing block %p...\n", block); | |
1da177e4 LT |
290 | |
291 | /* Remove block from file's list of blocks */ | |
68a2d76c | 292 | list_del_init(&block->b_flist); |
89e63ef6 | 293 | mutex_unlock(&file->f_mutex); |
1da177e4 | 294 | |
92737230 | 295 | nlmsvc_freegrantargs(block->b_call); |
7db836d4 | 296 | nlmsvc_release_call(block->b_call); |
d9f6eb75 | 297 | nlm_release_file(block->b_file); |
1da177e4 | 298 | kfree(block); |
6849c0ca TM |
299 | } |
300 | ||
301 | static void nlmsvc_release_block(struct nlm_block *block) | |
302 | { | |
303 | if (block != NULL) | |
c5aa1e55 | 304 | kref_put_mutex(&block->b_count, nlmsvc_free_block, &block->b_file->f_mutex); |
1da177e4 LT |
305 | } |
306 | ||
f2af793d OK |
307 | /* |
308 | * Loop over all blocks and delete blocks held by | |
309 | * a matching host. | |
310 | */ | |
311 | void nlmsvc_traverse_blocks(struct nlm_host *host, | |
312 | struct nlm_file *file, | |
313 | nlm_host_match_fn_t match) | |
d9f6eb75 | 314 | { |
68a2d76c | 315 | struct nlm_block *block, *next; |
d9f6eb75 TM |
316 | |
317 | restart: | |
89e63ef6 | 318 | mutex_lock(&file->f_mutex); |
68a2d76c | 319 | list_for_each_entry_safe(block, next, &file->f_blocks, b_flist) { |
f2af793d | 320 | if (!match(block->b_host, host)) |
d9f6eb75 | 321 | continue; |
68a2d76c OK |
322 | /* Do not destroy blocks that are not on |
323 | * the global retry list - why? */ | |
324 | if (list_empty(&block->b_list)) | |
d9f6eb75 TM |
325 | continue; |
326 | kref_get(&block->b_count); | |
89e63ef6 | 327 | mutex_unlock(&file->f_mutex); |
d9f6eb75 TM |
328 | nlmsvc_unlink_block(block); |
329 | nlmsvc_release_block(block); | |
330 | goto restart; | |
331 | } | |
89e63ef6 | 332 | mutex_unlock(&file->f_mutex); |
d9f6eb75 TM |
333 | } |
334 | ||
5e1abf8c TM |
335 | /* |
336 | * Initialize arguments for GRANTED call. The nlm_rqst structure | |
337 | * has been cleared already. | |
338 | */ | |
339 | static int nlmsvc_setgrantargs(struct nlm_rqst *call, struct nlm_lock *lock) | |
340 | { | |
341 | locks_copy_lock(&call->a_args.lock.fl, &lock->fl); | |
342 | memcpy(&call->a_args.lock.fh, &lock->fh, sizeof(call->a_args.lock.fh)); | |
e9ff3990 | 343 | call->a_args.lock.caller = utsname()->nodename; |
5e1abf8c TM |
344 | call->a_args.lock.oh.len = lock->oh.len; |
345 | ||
346 | /* set default data area */ | |
347 | call->a_args.lock.oh.data = call->a_owner; | |
348 | call->a_args.lock.svid = lock->fl.fl_pid; | |
349 | ||
350 | if (lock->oh.len > NLMCLNT_OHSIZE) { | |
351 | void *data = kmalloc(lock->oh.len, GFP_KERNEL); | |
92737230 | 352 | if (!data) |
5e1abf8c | 353 | return 0; |
5e1abf8c TM |
354 | call->a_args.lock.oh.data = (u8 *) data; |
355 | } | |
356 | ||
357 | memcpy(call->a_args.lock.oh.data, lock->oh.data, lock->oh.len); | |
358 | return 1; | |
359 | } | |
360 | ||
361 | static void nlmsvc_freegrantargs(struct nlm_rqst *call) | |
362 | { | |
92737230 | 363 | if (call->a_args.lock.oh.data != call->a_owner) |
5e1abf8c | 364 | kfree(call->a_args.lock.oh.data); |
a9e61e25 FB |
365 | |
366 | locks_release_private(&call->a_args.lock.fl); | |
5e1abf8c TM |
367 | } |
368 | ||
2b36f412 ME |
369 | /* |
370 | * Deferred lock request handling for non-blocking lock | |
371 | */ | |
ca5c8cde | 372 | static __be32 |
2b36f412 ME |
373 | nlmsvc_defer_lock_rqst(struct svc_rqst *rqstp, struct nlm_block *block) |
374 | { | |
ca5c8cde | 375 | __be32 status = nlm_lck_denied_nolocks; |
2b36f412 ME |
376 | |
377 | block->b_flags |= B_QUEUED; | |
378 | ||
379 | nlmsvc_insert_block(block, NLM_TIMEOUT); | |
380 | ||
381 | block->b_cache_req = &rqstp->rq_chandle; | |
382 | if (rqstp->rq_chandle.defer) { | |
383 | block->b_deferred_req = | |
384 | rqstp->rq_chandle.defer(block->b_cache_req); | |
385 | if (block->b_deferred_req != NULL) | |
386 | status = nlm_drop_reply; | |
387 | } | |
388 | dprintk("lockd: nlmsvc_defer_lock_rqst block %p flags %d status %d\n", | |
ca5c8cde | 389 | block, block->b_flags, ntohl(status)); |
2b36f412 ME |
390 | |
391 | return status; | |
392 | } | |
393 | ||
1da177e4 LT |
394 | /* |
395 | * Attempt to establish a lock, and if it can't be granted, block it | |
396 | * if required. | |
397 | */ | |
52921e02 | 398 | __be32 |
1da177e4 | 399 | nlmsvc_lock(struct svc_rqst *rqstp, struct nlm_file *file, |
6cde4de8 | 400 | struct nlm_host *host, struct nlm_lock *lock, int wait, |
b2b50289 | 401 | struct nlm_cookie *cookie, int reclaim) |
1da177e4 | 402 | { |
f8120480 | 403 | struct nlm_block *block = NULL; |
1da177e4 | 404 | int error; |
52921e02 | 405 | __be32 ret; |
1da177e4 LT |
406 | |
407 | dprintk("lockd: nlmsvc_lock(%s/%ld, ty=%d, pi=%d, %Ld-%Ld, bl=%d)\n", | |
496ad9aa AV |
408 | file_inode(file->f_file)->i_sb->s_id, |
409 | file_inode(file->f_file)->i_ino, | |
1da177e4 LT |
410 | lock->fl.fl_type, lock->fl.fl_pid, |
411 | (long long)lock->fl.fl_start, | |
412 | (long long)lock->fl.fl_end, | |
413 | wait); | |
414 | ||
1da177e4 | 415 | /* Lock file against concurrent access */ |
89e63ef6 | 416 | mutex_lock(&file->f_mutex); |
f8120480 ME |
417 | /* Get existing block (in case client is busy-waiting) |
418 | * or create new block | |
419 | */ | |
d9f6eb75 | 420 | block = nlmsvc_lookup_block(file, lock); |
09c7938c | 421 | if (block == NULL) { |
560de0e6 | 422 | block = nlmsvc_create_block(rqstp, host, file, lock, cookie); |
f8120480 ME |
423 | ret = nlm_lck_denied_nolocks; |
424 | if (block == NULL) | |
425 | goto out; | |
92737230 | 426 | lock = &block->b_call->a_args.lock; |
f8120480 ME |
427 | } else |
428 | lock->fl.fl_flags &= ~FL_SLEEP; | |
1da177e4 | 429 | |
1a8322b2 ME |
430 | if (block->b_flags & B_QUEUED) { |
431 | dprintk("lockd: nlmsvc_lock deferred block %p flags %d\n", | |
432 | block, block->b_flags); | |
433 | if (block->b_granted) { | |
434 | nlmsvc_unlink_block(block); | |
435 | ret = nlm_granted; | |
436 | goto out; | |
437 | } | |
438 | if (block->b_flags & B_TIMED_OUT) { | |
439 | nlmsvc_unlink_block(block); | |
440 | ret = nlm_lck_denied; | |
441 | goto out; | |
442 | } | |
443 | ret = nlm_drop_reply; | |
444 | goto out; | |
445 | } | |
1da177e4 | 446 | |
5ccb0066 | 447 | if (locks_in_grace(SVC_NET(rqstp)) && !reclaim) { |
b2b50289 BF |
448 | ret = nlm_lck_denied_grace_period; |
449 | goto out; | |
450 | } | |
5ccb0066 | 451 | if (reclaim && !locks_in_grace(SVC_NET(rqstp))) { |
d22b1cff BF |
452 | ret = nlm_lck_denied_grace_period; |
453 | goto out; | |
454 | } | |
b2b50289 | 455 | |
1a8322b2 ME |
456 | if (!wait) |
457 | lock->fl.fl_flags &= ~FL_SLEEP; | |
458 | error = vfs_lock_file(file->f_file, F_SETLK, &lock->fl, NULL); | |
459 | lock->fl.fl_flags &= ~FL_SLEEP; | |
a85f193e | 460 | |
1a8322b2 | 461 | dprintk("lockd: vfs_lock_file returned %d\n", error); |
6d7bbbba | 462 | switch (error) { |
1da177e4 | 463 | case 0: |
15dadef9 AA |
464 | ret = nlm_granted; |
465 | goto out; | |
09c7938c | 466 | case -EAGAIN: |
e33d1ea6 MS |
467 | /* |
468 | * If this is a blocking request for an | |
469 | * already pending lock request then we need | |
470 | * to put it back on lockd's block list | |
471 | */ | |
472 | if (wait) | |
473 | break; | |
1a8322b2 | 474 | ret = nlm_lck_denied; |
e33d1ea6 | 475 | goto out; |
bde74e4b | 476 | case FILE_LOCK_DEFERRED: |
1a8322b2 ME |
477 | if (wait) |
478 | break; | |
479 | /* Filesystem lock operation is in progress | |
480 | Add it to the queue waiting for callback */ | |
481 | ret = nlmsvc_defer_lock_rqst(rqstp, block); | |
482 | goto out; | |
09c7938c | 483 | case -EDEADLK: |
15dadef9 AA |
484 | ret = nlm_deadlock; |
485 | goto out; | |
1da177e4 | 486 | default: /* includes ENOLCK */ |
15dadef9 AA |
487 | ret = nlm_lck_denied_nolocks; |
488 | goto out; | |
1da177e4 LT |
489 | } |
490 | ||
09c7938c | 491 | ret = nlm_lck_blocked; |
1da177e4 LT |
492 | |
493 | /* Append to list of blocked */ | |
f8120480 | 494 | nlmsvc_insert_block(block, NLM_NEVER); |
15dadef9 | 495 | out: |
89e63ef6 | 496 | mutex_unlock(&file->f_mutex); |
6849c0ca | 497 | nlmsvc_release_block(block); |
15dadef9 AA |
498 | dprintk("lockd: nlmsvc_lock returned %u\n", ret); |
499 | return ret; | |
1da177e4 LT |
500 | } |
501 | ||
502 | /* | |
503 | * Test for presence of a conflicting lock. | |
504 | */ | |
52921e02 | 505 | __be32 |
85f3f1b3 | 506 | nlmsvc_testlock(struct svc_rqst *rqstp, struct nlm_file *file, |
8f920d5e JL |
507 | struct nlm_host *host, struct nlm_lock *lock, |
508 | struct nlm_lock *conflock, struct nlm_cookie *cookie) | |
1da177e4 | 509 | { |
5ea0d750 ME |
510 | int error; |
511 | __be32 ret; | |
512 | ||
1da177e4 | 513 | dprintk("lockd: nlmsvc_testlock(%s/%ld, ty=%d, %Ld-%Ld)\n", |
496ad9aa AV |
514 | file_inode(file->f_file)->i_sb->s_id, |
515 | file_inode(file->f_file)->i_ino, | |
1da177e4 LT |
516 | lock->fl.fl_type, |
517 | (long long)lock->fl.fl_start, | |
518 | (long long)lock->fl.fl_end); | |
519 | ||
5ccb0066 | 520 | if (locks_in_grace(SVC_NET(rqstp))) { |
b2b50289 BF |
521 | ret = nlm_lck_denied_grace_period; |
522 | goto out; | |
523 | } | |
09802fd2 | 524 | |
5ea0d750 | 525 | error = vfs_test_lock(file->f_file, &lock->fl); |
5ea0d750 | 526 | if (error) { |
09802fd2 JL |
527 | /* We can't currently deal with deferred test requests */ |
528 | if (error == FILE_LOCK_DEFERRED) | |
529 | WARN_ON_ONCE(1); | |
530 | ||
5ea0d750 ME |
531 | ret = nlm_lck_denied_nolocks; |
532 | goto out; | |
533 | } | |
09802fd2 | 534 | |
5ea0d750 ME |
535 | if (lock->fl.fl_type == F_UNLCK) { |
536 | ret = nlm_granted; | |
537 | goto out; | |
538 | } | |
539 | ||
5ea0d750 ME |
540 | dprintk("lockd: conflicting lock(ty=%d, %Ld-%Ld)\n", |
541 | lock->fl.fl_type, (long long)lock->fl.fl_start, | |
542 | (long long)lock->fl.fl_end); | |
543 | conflock->caller = "somehost"; /* FIXME */ | |
544 | conflock->len = strlen(conflock->caller); | |
545 | conflock->oh.len = 0; /* don't return OH info */ | |
546 | conflock->svid = lock->fl.fl_pid; | |
547 | conflock->fl.fl_type = lock->fl.fl_type; | |
548 | conflock->fl.fl_start = lock->fl.fl_start; | |
549 | conflock->fl.fl_end = lock->fl.fl_end; | |
f328296e | 550 | locks_release_private(&lock->fl); |
5ea0d750 ME |
551 | ret = nlm_lck_denied; |
552 | out: | |
5ea0d750 | 553 | return ret; |
1da177e4 LT |
554 | } |
555 | ||
556 | /* | |
557 | * Remove a lock. | |
558 | * This implies a CANCEL call: We send a GRANT_MSG, the client replies | |
559 | * with a GRANT_RES call which gets lost, and calls UNLOCK immediately | |
560 | * afterwards. In this case the block will still be there, and hence | |
561 | * must be removed. | |
562 | */ | |
52921e02 | 563 | __be32 |
5ccb0066 | 564 | nlmsvc_unlock(struct net *net, struct nlm_file *file, struct nlm_lock *lock) |
1da177e4 LT |
565 | { |
566 | int error; | |
567 | ||
568 | dprintk("lockd: nlmsvc_unlock(%s/%ld, pi=%d, %Ld-%Ld)\n", | |
496ad9aa AV |
569 | file_inode(file->f_file)->i_sb->s_id, |
570 | file_inode(file->f_file)->i_ino, | |
1da177e4 LT |
571 | lock->fl.fl_pid, |
572 | (long long)lock->fl.fl_start, | |
573 | (long long)lock->fl.fl_end); | |
574 | ||
575 | /* First, cancel any lock that might be there */ | |
5ccb0066 | 576 | nlmsvc_cancel_blocked(net, file, lock); |
1da177e4 LT |
577 | |
578 | lock->fl.fl_type = F_UNLCK; | |
1a8322b2 | 579 | error = vfs_lock_file(file->f_file, F_SETLK, &lock->fl, NULL); |
1da177e4 LT |
580 | |
581 | return (error < 0)? nlm_lck_denied_nolocks : nlm_granted; | |
582 | } | |
583 | ||
584 | /* | |
585 | * Cancel a previously blocked request. | |
586 | * | |
587 | * A cancel request always overrides any grant that may currently | |
588 | * be in progress. | |
589 | * The calling procedure must check whether the file can be closed. | |
590 | */ | |
52921e02 | 591 | __be32 |
5ccb0066 | 592 | nlmsvc_cancel_blocked(struct net *net, struct nlm_file *file, struct nlm_lock *lock) |
1da177e4 LT |
593 | { |
594 | struct nlm_block *block; | |
64a318ee | 595 | int status = 0; |
1da177e4 LT |
596 | |
597 | dprintk("lockd: nlmsvc_cancel(%s/%ld, pi=%d, %Ld-%Ld)\n", | |
496ad9aa AV |
598 | file_inode(file->f_file)->i_sb->s_id, |
599 | file_inode(file->f_file)->i_ino, | |
1da177e4 LT |
600 | lock->fl.fl_pid, |
601 | (long long)lock->fl.fl_start, | |
602 | (long long)lock->fl.fl_end); | |
603 | ||
5ccb0066 | 604 | if (locks_in_grace(net)) |
b2b50289 BF |
605 | return nlm_lck_denied_grace_period; |
606 | ||
89e63ef6 | 607 | mutex_lock(&file->f_mutex); |
d9f6eb75 | 608 | block = nlmsvc_lookup_block(file, lock); |
89e63ef6 | 609 | mutex_unlock(&file->f_mutex); |
d9f6eb75 | 610 | if (block != NULL) { |
1a8322b2 ME |
611 | vfs_cancel_lock(block->b_file->f_file, |
612 | &block->b_call->a_args.lock.fl); | |
6849c0ca TM |
613 | status = nlmsvc_unlink_block(block); |
614 | nlmsvc_release_block(block); | |
615 | } | |
64a318ee | 616 | return status ? nlm_lck_denied : nlm_granted; |
1da177e4 LT |
617 | } |
618 | ||
0e4ac9d9 ME |
619 | /* |
620 | * This is a callback from the filesystem for VFS file lock requests. | |
8fb47a4f | 621 | * It will be used if lm_grant is defined and the filesystem can not |
0e4ac9d9 | 622 | * respond to the request immediately. |
0e4ac9d9 ME |
623 | * For SETLK or SETLKW request it will get the local posix lock. |
624 | * In all cases it will move the block to the head of nlm_blocked q where | |
625 | * nlmsvc_retry_blocked() can send back a reply for SETLKW or revisit the | |
626 | * deferred rpc for GETLK and SETLK. | |
627 | */ | |
628 | static void | |
d0449b90 | 629 | nlmsvc_update_deferred_block(struct nlm_block *block, int result) |
0e4ac9d9 ME |
630 | { |
631 | block->b_flags |= B_GOT_CALLBACK; | |
632 | if (result == 0) | |
633 | block->b_granted = 1; | |
634 | else | |
635 | block->b_flags |= B_TIMED_OUT; | |
0e4ac9d9 ME |
636 | } |
637 | ||
d0449b90 | 638 | static int nlmsvc_grant_deferred(struct file_lock *fl, int result) |
0e4ac9d9 ME |
639 | { |
640 | struct nlm_block *block; | |
641 | int rc = -ENOENT; | |
642 | ||
f904be9c | 643 | spin_lock(&nlm_blocked_lock); |
0e4ac9d9 ME |
644 | list_for_each_entry(block, &nlm_blocked, b_list) { |
645 | if (nlm_compare_locks(&block->b_call->a_args.lock.fl, fl)) { | |
646 | dprintk("lockd: nlmsvc_notify_blocked block %p flags %d\n", | |
647 | block, block->b_flags); | |
648 | if (block->b_flags & B_QUEUED) { | |
649 | if (block->b_flags & B_TIMED_OUT) { | |
650 | rc = -ENOLCK; | |
651 | break; | |
652 | } | |
d0449b90 | 653 | nlmsvc_update_deferred_block(block, result); |
0e4ac9d9 ME |
654 | } else if (result == 0) |
655 | block->b_granted = 1; | |
656 | ||
f904be9c | 657 | nlmsvc_insert_block_locked(block, 0); |
0e4ac9d9 ME |
658 | svc_wake_up(block->b_daemon); |
659 | rc = 0; | |
660 | break; | |
661 | } | |
662 | } | |
f904be9c | 663 | spin_unlock(&nlm_blocked_lock); |
0e4ac9d9 ME |
664 | if (rc == -ENOENT) |
665 | printk(KERN_WARNING "lockd: grant for unknown block\n"); | |
666 | return rc; | |
667 | } | |
668 | ||
1da177e4 LT |
669 | /* |
670 | * Unblock a blocked lock request. This is a callback invoked from the | |
671 | * VFS layer when a lock on which we blocked is removed. | |
672 | * | |
673 | * This function doesn't grant the blocked lock instantly, but rather moves | |
674 | * the block to the head of nlm_blocked where it can be picked up by lockd. | |
675 | */ | |
676 | static void | |
677 | nlmsvc_notify_blocked(struct file_lock *fl) | |
678 | { | |
68a2d76c | 679 | struct nlm_block *block; |
1da177e4 LT |
680 | |
681 | dprintk("lockd: VFS unblock notification for block %p\n", fl); | |
a282a1fa | 682 | spin_lock(&nlm_blocked_lock); |
68a2d76c | 683 | list_for_each_entry(block, &nlm_blocked, b_list) { |
92737230 | 684 | if (nlm_compare_locks(&block->b_call->a_args.lock.fl, fl)) { |
a282a1fa BF |
685 | nlmsvc_insert_block_locked(block, 0); |
686 | spin_unlock(&nlm_blocked_lock); | |
1da177e4 LT |
687 | svc_wake_up(block->b_daemon); |
688 | return; | |
689 | } | |
690 | } | |
a282a1fa | 691 | spin_unlock(&nlm_blocked_lock); |
1da177e4 LT |
692 | printk(KERN_WARNING "lockd: notification for unknown block!\n"); |
693 | } | |
694 | ||
695 | static int nlmsvc_same_owner(struct file_lock *fl1, struct file_lock *fl2) | |
696 | { | |
697 | return fl1->fl_owner == fl2->fl_owner && fl1->fl_pid == fl2->fl_pid; | |
698 | } | |
699 | ||
3999e493 JL |
700 | /* |
701 | * Since NLM uses two "keys" for tracking locks, we need to hash them down | |
702 | * to one for the blocked_hash. Here, we're just xor'ing the host address | |
703 | * with the pid in order to create a key value for picking a hash bucket. | |
704 | */ | |
705 | static unsigned long | |
706 | nlmsvc_owner_key(struct file_lock *fl) | |
707 | { | |
708 | return (unsigned long)fl->fl_owner ^ (unsigned long)fl->fl_pid; | |
709 | } | |
710 | ||
7b021967 | 711 | const struct lock_manager_operations nlmsvc_lock_operations = { |
8fb47a4f | 712 | .lm_compare_owner = nlmsvc_same_owner, |
3999e493 | 713 | .lm_owner_key = nlmsvc_owner_key, |
8fb47a4f BF |
714 | .lm_notify = nlmsvc_notify_blocked, |
715 | .lm_grant = nlmsvc_grant_deferred, | |
1da177e4 LT |
716 | }; |
717 | ||
718 | /* | |
719 | * Try to claim a lock that was previously blocked. | |
720 | * | |
721 | * Note that we use both the RPC_GRANTED_MSG call _and_ an async | |
722 | * RPC thread when notifying the client. This seems like overkill... | |
723 | * Here's why: | |
724 | * - we don't want to use a synchronous RPC thread, otherwise | |
725 | * we might find ourselves hanging on a dead portmapper. | |
726 | * - Some lockd implementations (e.g. HP) don't react to | |
727 | * RPC_GRANTED calls; they seem to insist on RPC_GRANTED_MSG calls. | |
728 | */ | |
729 | static void | |
730 | nlmsvc_grant_blocked(struct nlm_block *block) | |
731 | { | |
732 | struct nlm_file *file = block->b_file; | |
92737230 | 733 | struct nlm_lock *lock = &block->b_call->a_args.lock; |
1da177e4 | 734 | int error; |
2ec197db | 735 | loff_t fl_start, fl_end; |
1da177e4 LT |
736 | |
737 | dprintk("lockd: grant blocked lock %p\n", block); | |
738 | ||
0e4ac9d9 ME |
739 | kref_get(&block->b_count); |
740 | ||
1da177e4 | 741 | /* Unlink block request from list */ |
6849c0ca | 742 | nlmsvc_unlink_block(block); |
1da177e4 LT |
743 | |
744 | /* If b_granted is true this means we've been here before. | |
745 | * Just retry the grant callback, possibly refreshing the RPC | |
746 | * binding */ | |
747 | if (block->b_granted) { | |
748 | nlm_rebind_host(block->b_host); | |
749 | goto callback; | |
750 | } | |
751 | ||
752 | /* Try the lock operation again */ | |
2ec197db N |
753 | /* vfs_lock_file() can mangle fl_start and fl_end, but we need |
754 | * them unchanged for the GRANT_MSG | |
755 | */ | |
09c7938c | 756 | lock->fl.fl_flags |= FL_SLEEP; |
2ec197db N |
757 | fl_start = lock->fl.fl_start; |
758 | fl_end = lock->fl.fl_end; | |
1a8322b2 | 759 | error = vfs_lock_file(file->f_file, F_SETLK, &lock->fl, NULL); |
09c7938c | 760 | lock->fl.fl_flags &= ~FL_SLEEP; |
2ec197db N |
761 | lock->fl.fl_start = fl_start; |
762 | lock->fl.fl_end = fl_end; | |
09c7938c | 763 | |
5de0e502 AA |
764 | switch (error) { |
765 | case 0: | |
766 | break; | |
bde74e4b | 767 | case FILE_LOCK_DEFERRED: |
1a8322b2 | 768 | dprintk("lockd: lock still blocked error %d\n", error); |
1da177e4 | 769 | nlmsvc_insert_block(block, NLM_NEVER); |
0e4ac9d9 | 770 | nlmsvc_release_block(block); |
d9f6eb75 | 771 | return; |
5de0e502 | 772 | default: |
1da177e4 | 773 | printk(KERN_WARNING "lockd: unexpected error %d in %s!\n", |
8e24eea7 | 774 | -error, __func__); |
1da177e4 | 775 | nlmsvc_insert_block(block, 10 * HZ); |
0e4ac9d9 | 776 | nlmsvc_release_block(block); |
d9f6eb75 | 777 | return; |
1da177e4 LT |
778 | } |
779 | ||
780 | callback: | |
781 | /* Lock was granted by VFS. */ | |
782 | dprintk("lockd: GRANTing blocked lock.\n"); | |
783 | block->b_granted = 1; | |
1da177e4 | 784 | |
9706501e JL |
785 | /* keep block on the list, but don't reattempt until the RPC |
786 | * completes or the submission fails | |
787 | */ | |
788 | nlmsvc_insert_block(block, NLM_NEVER); | |
1da177e4 | 789 | |
9706501e JL |
790 | /* Call the client -- use a soft RPC task since nlmsvc_retry_blocked |
791 | * will queue up a new one if this one times out | |
792 | */ | |
793 | error = nlm_async_call(block->b_call, NLMPROC_GRANTED_MSG, | |
794 | &nlmsvc_grant_ops); | |
795 | ||
796 | /* RPC submission failed, wait a bit and retry */ | |
797 | if (error < 0) | |
798 | nlmsvc_insert_block(block, 10 * HZ); | |
1da177e4 LT |
799 | } |
800 | ||
801 | /* | |
802 | * This is the callback from the RPC layer when the NLM_GRANTED_MSG | |
803 | * RPC call has succeeded or timed out. | |
804 | * Like all RPC callbacks, it is invoked by the rpciod process, so it | |
805 | * better not sleep. Therefore, we put the blocked lock on the nlm_blocked | |
806 | * chain once more in order to have it removed by lockd itself (which can | |
807 | * then sleep on the file semaphore without disrupting e.g. the nfs client). | |
808 | */ | |
963d8fe5 | 809 | static void nlmsvc_grant_callback(struct rpc_task *task, void *data) |
1da177e4 | 810 | { |
963d8fe5 | 811 | struct nlm_rqst *call = data; |
92737230 | 812 | struct nlm_block *block = call->a_block; |
1da177e4 | 813 | unsigned long timeout; |
1da177e4 LT |
814 | |
815 | dprintk("lockd: GRANT_MSG RPC callback\n"); | |
1da177e4 | 816 | |
f904be9c | 817 | spin_lock(&nlm_blocked_lock); |
c64e80d5 JL |
818 | /* if the block is not on a list at this point then it has |
819 | * been invalidated. Don't try to requeue it. | |
820 | * | |
821 | * FIXME: it's possible that the block is removed from the list | |
822 | * after this check but before the nlmsvc_insert_block. In that | |
823 | * case it will be added back. Perhaps we need better locking | |
824 | * for nlm_blocked? | |
825 | */ | |
826 | if (list_empty(&block->b_list)) | |
a86dc496 | 827 | goto out; |
c64e80d5 | 828 | |
1da177e4 LT |
829 | /* Technically, we should down the file semaphore here. Since we |
830 | * move the block towards the head of the queue only, no harm | |
831 | * can be done, though. */ | |
832 | if (task->tk_status < 0) { | |
833 | /* RPC error: Re-insert for retransmission */ | |
834 | timeout = 10 * HZ; | |
1da177e4 LT |
835 | } else { |
836 | /* Call was successful, now wait for client callback */ | |
837 | timeout = 60 * HZ; | |
838 | } | |
f904be9c | 839 | nlmsvc_insert_block_locked(block, timeout); |
1da177e4 | 840 | svc_wake_up(block->b_daemon); |
a86dc496 | 841 | out: |
f904be9c | 842 | spin_unlock(&nlm_blocked_lock); |
5e1abf8c TM |
843 | } |
844 | ||
f904be9c BS |
845 | /* |
846 | * FIXME: nlmsvc_release_block() grabs a mutex. This is not allowed for an | |
847 | * .rpc_release rpc_call_op | |
848 | */ | |
ec535ce1 | 849 | static void nlmsvc_grant_release(void *data) |
5e1abf8c | 850 | { |
6041b791 | 851 | struct nlm_rqst *call = data; |
6041b791 | 852 | nlmsvc_release_block(call->a_block); |
1da177e4 LT |
853 | } |
854 | ||
963d8fe5 TM |
855 | static const struct rpc_call_ops nlmsvc_grant_ops = { |
856 | .rpc_call_done = nlmsvc_grant_callback, | |
5e1abf8c | 857 | .rpc_release = nlmsvc_grant_release, |
963d8fe5 TM |
858 | }; |
859 | ||
1da177e4 LT |
860 | /* |
861 | * We received a GRANT_RES callback. Try to find the corresponding | |
862 | * block. | |
863 | */ | |
864 | void | |
e8c5c045 | 865 | nlmsvc_grant_reply(struct nlm_cookie *cookie, __be32 status) |
1da177e4 LT |
866 | { |
867 | struct nlm_block *block; | |
1da177e4 | 868 | |
39be4502 OK |
869 | dprintk("grant_reply: looking for cookie %x, s=%d \n", |
870 | *(unsigned int *)(cookie->data), status); | |
871 | if (!(block = nlmsvc_find_block(cookie))) | |
1da177e4 | 872 | return; |
1da177e4 | 873 | |
e56efe93 CIK |
874 | if (status == nlm_lck_denied_grace_period) { |
875 | /* Try again in a couple of seconds */ | |
876 | nlmsvc_insert_block(block, 10 * HZ); | |
877 | } else { | |
878 | /* | |
879 | * Lock is now held by client, or has been rejected. | |
880 | * In both cases, the block should be removed. | |
881 | */ | |
882 | nlmsvc_unlink_block(block); | |
1da177e4 | 883 | } |
6849c0ca | 884 | nlmsvc_release_block(block); |
1da177e4 LT |
885 | } |
886 | ||
0e4ac9d9 ME |
887 | /* Helper function to handle retry of a deferred block. |
888 | * If it is a blocking lock, call grant_blocked. | |
889 | * For a non-blocking lock or test lock, revisit the request. | |
890 | */ | |
891 | static void | |
892 | retry_deferred_block(struct nlm_block *block) | |
893 | { | |
894 | if (!(block->b_flags & B_GOT_CALLBACK)) | |
895 | block->b_flags |= B_TIMED_OUT; | |
896 | nlmsvc_insert_block(block, NLM_TIMEOUT); | |
897 | dprintk("revisit block %p flags %d\n", block, block->b_flags); | |
898 | if (block->b_deferred_req) { | |
899 | block->b_deferred_req->revisit(block->b_deferred_req, 0); | |
900 | block->b_deferred_req = NULL; | |
901 | } | |
902 | } | |
903 | ||
1da177e4 LT |
904 | /* |
905 | * Retry all blocked locks that have been notified. This is where lockd | |
906 | * picks up locks that can be granted, or grant notifications that must | |
907 | * be retransmitted. | |
908 | */ | |
909 | unsigned long | |
910 | nlmsvc_retry_blocked(void) | |
911 | { | |
68a2d76c OK |
912 | unsigned long timeout = MAX_SCHEDULE_TIMEOUT; |
913 | struct nlm_block *block; | |
914 | ||
1c327d96 | 915 | spin_lock(&nlm_blocked_lock); |
d751a7cd | 916 | while (!list_empty(&nlm_blocked) && !kthread_should_stop()) { |
68a2d76c | 917 | block = list_entry(nlm_blocked.next, struct nlm_block, b_list); |
1da177e4 | 918 | |
1da177e4 LT |
919 | if (block->b_when == NLM_NEVER) |
920 | break; | |
6d7bbbba | 921 | if (time_after(block->b_when, jiffies)) { |
68a2d76c | 922 | timeout = block->b_when - jiffies; |
1da177e4 | 923 | break; |
68a2d76c | 924 | } |
1c327d96 | 925 | spin_unlock(&nlm_blocked_lock); |
68a2d76c | 926 | |
f3d43c76 BF |
927 | dprintk("nlmsvc_retry_blocked(%p, when=%ld)\n", |
928 | block, block->b_when); | |
0e4ac9d9 ME |
929 | if (block->b_flags & B_QUEUED) { |
930 | dprintk("nlmsvc_retry_blocked delete block (%p, granted=%d, flags=%d)\n", | |
931 | block, block->b_granted, block->b_flags); | |
932 | retry_deferred_block(block); | |
933 | } else | |
934 | nlmsvc_grant_blocked(block); | |
1c327d96 | 935 | spin_lock(&nlm_blocked_lock); |
1da177e4 | 936 | } |
1c327d96 | 937 | spin_unlock(&nlm_blocked_lock); |
1da177e4 | 938 | |
68a2d76c | 939 | return timeout; |
1da177e4 | 940 | } |