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1 | /* -*- mode: c; c-basic-offset: 8; -*- |
2 | * vim: noexpandtab sw=8 ts=8 sts=0: | |
3 | * | |
4 | * userdlm.c | |
5 | * | |
6 | * Code which implements the kernel side of a minimal userspace | |
7 | * interface to our DLM. | |
8 | * | |
9 | * Many of the functions here are pared down versions of dlmglue.c | |
10 | * functions. | |
11 | * | |
12 | * Copyright (C) 2003, 2004 Oracle. All rights reserved. | |
13 | * | |
14 | * This program is free software; you can redistribute it and/or | |
15 | * modify it under the terms of the GNU General Public | |
16 | * License as published by the Free Software Foundation; either | |
17 | * version 2 of the License, or (at your option) any later version. | |
18 | * | |
19 | * This program is distributed in the hope that it will be useful, | |
20 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
21 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
22 | * General Public License for more details. | |
23 | * | |
24 | * You should have received a copy of the GNU General Public | |
25 | * License along with this program; if not, write to the | |
26 | * Free Software Foundation, Inc., 59 Temple Place - Suite 330, | |
27 | * Boston, MA 021110-1307, USA. | |
28 | */ | |
29 | ||
30 | #include <asm/signal.h> | |
31 | ||
32 | #include <linux/module.h> | |
33 | #include <linux/fs.h> | |
34 | #include <linux/types.h> | |
35 | #include <linux/crc32.h> | |
36 | ||
37 | ||
38 | #include "cluster/nodemanager.h" | |
39 | #include "cluster/heartbeat.h" | |
40 | #include "cluster/tcp.h" | |
41 | ||
42 | #include "dlmapi.h" | |
43 | ||
44 | #include "userdlm.h" | |
45 | ||
46 | #define MLOG_MASK_PREFIX ML_DLMFS | |
47 | #include "cluster/masklog.h" | |
48 | ||
49 | static inline int user_check_wait_flag(struct user_lock_res *lockres, | |
50 | int flag) | |
51 | { | |
52 | int ret; | |
53 | ||
54 | spin_lock(&lockres->l_lock); | |
55 | ret = lockres->l_flags & flag; | |
56 | spin_unlock(&lockres->l_lock); | |
57 | ||
58 | return ret; | |
59 | } | |
60 | ||
61 | static inline void user_wait_on_busy_lock(struct user_lock_res *lockres) | |
62 | ||
63 | { | |
64 | wait_event(lockres->l_event, | |
65 | !user_check_wait_flag(lockres, USER_LOCK_BUSY)); | |
66 | } | |
67 | ||
68 | static inline void user_wait_on_blocked_lock(struct user_lock_res *lockres) | |
69 | ||
70 | { | |
71 | wait_event(lockres->l_event, | |
72 | !user_check_wait_flag(lockres, USER_LOCK_BLOCKED)); | |
73 | } | |
74 | ||
75 | /* I heart container_of... */ | |
76 | static inline struct dlm_ctxt * | |
77 | dlm_ctxt_from_user_lockres(struct user_lock_res *lockres) | |
78 | { | |
79 | struct dlmfs_inode_private *ip; | |
80 | ||
81 | ip = container_of(lockres, | |
82 | struct dlmfs_inode_private, | |
83 | ip_lockres); | |
84 | return ip->ip_dlm; | |
85 | } | |
86 | ||
87 | static struct inode * | |
88 | user_dlm_inode_from_user_lockres(struct user_lock_res *lockres) | |
89 | { | |
90 | struct dlmfs_inode_private *ip; | |
91 | ||
92 | ip = container_of(lockres, | |
93 | struct dlmfs_inode_private, | |
94 | ip_lockres); | |
95 | return &ip->ip_vfs_inode; | |
96 | } | |
97 | ||
98 | static inline void user_recover_from_dlm_error(struct user_lock_res *lockres) | |
99 | { | |
100 | spin_lock(&lockres->l_lock); | |
101 | lockres->l_flags &= ~USER_LOCK_BUSY; | |
102 | spin_unlock(&lockres->l_lock); | |
103 | } | |
104 | ||
105 | #define user_log_dlm_error(_func, _stat, _lockres) do { \ | |
106 | mlog(ML_ERROR, "Dlm error \"%s\" while calling %s on " \ | |
107 | "resource %s: %s\n", dlm_errname(_stat), _func, \ | |
108 | _lockres->l_name, dlm_errmsg(_stat)); \ | |
109 | } while (0) | |
110 | ||
111 | /* WARNING: This function lives in a world where the only three lock | |
112 | * levels are EX, PR, and NL. It *will* have to be adjusted when more | |
113 | * lock types are added. */ | |
114 | static inline int user_highest_compat_lock_level(int level) | |
115 | { | |
116 | int new_level = LKM_EXMODE; | |
117 | ||
118 | if (level == LKM_EXMODE) | |
119 | new_level = LKM_NLMODE; | |
120 | else if (level == LKM_PRMODE) | |
121 | new_level = LKM_PRMODE; | |
122 | return new_level; | |
123 | } | |
124 | ||
125 | static void user_ast(void *opaque) | |
126 | { | |
127 | struct user_lock_res *lockres = opaque; | |
128 | struct dlm_lockstatus *lksb; | |
129 | ||
130 | mlog(0, "AST fired for lockres %s\n", lockres->l_name); | |
131 | ||
132 | spin_lock(&lockres->l_lock); | |
133 | ||
134 | lksb = &(lockres->l_lksb); | |
135 | if (lksb->status != DLM_NORMAL) { | |
136 | mlog(ML_ERROR, "lksb status value of %u on lockres %s\n", | |
137 | lksb->status, lockres->l_name); | |
138 | spin_unlock(&lockres->l_lock); | |
139 | return; | |
140 | } | |
141 | ||
142 | /* we're downconverting. */ | |
143 | if (lockres->l_requested < lockres->l_level) { | |
144 | if (lockres->l_requested <= | |
145 | user_highest_compat_lock_level(lockres->l_blocking)) { | |
146 | lockres->l_blocking = LKM_NLMODE; | |
147 | lockres->l_flags &= ~USER_LOCK_BLOCKED; | |
148 | } | |
149 | } | |
150 | ||
151 | lockres->l_level = lockres->l_requested; | |
152 | lockres->l_requested = LKM_IVMODE; | |
153 | lockres->l_flags |= USER_LOCK_ATTACHED; | |
154 | lockres->l_flags &= ~USER_LOCK_BUSY; | |
155 | ||
156 | spin_unlock(&lockres->l_lock); | |
157 | ||
158 | wake_up(&lockres->l_event); | |
159 | } | |
160 | ||
161 | static inline void user_dlm_grab_inode_ref(struct user_lock_res *lockres) | |
162 | { | |
163 | struct inode *inode; | |
164 | inode = user_dlm_inode_from_user_lockres(lockres); | |
165 | if (!igrab(inode)) | |
166 | BUG(); | |
167 | } | |
168 | ||
169 | static void user_dlm_unblock_lock(void *opaque); | |
170 | ||
171 | static void __user_dlm_queue_lockres(struct user_lock_res *lockres) | |
172 | { | |
173 | if (!(lockres->l_flags & USER_LOCK_QUEUED)) { | |
174 | user_dlm_grab_inode_ref(lockres); | |
175 | ||
176 | INIT_WORK(&lockres->l_work, user_dlm_unblock_lock, | |
177 | lockres); | |
178 | ||
179 | queue_work(user_dlm_worker, &lockres->l_work); | |
180 | lockres->l_flags |= USER_LOCK_QUEUED; | |
181 | } | |
182 | } | |
183 | ||
184 | static void __user_dlm_cond_queue_lockres(struct user_lock_res *lockres) | |
185 | { | |
186 | int queue = 0; | |
187 | ||
188 | if (!(lockres->l_flags & USER_LOCK_BLOCKED)) | |
189 | return; | |
190 | ||
191 | switch (lockres->l_blocking) { | |
192 | case LKM_EXMODE: | |
193 | if (!lockres->l_ex_holders && !lockres->l_ro_holders) | |
194 | queue = 1; | |
195 | break; | |
196 | case LKM_PRMODE: | |
197 | if (!lockres->l_ex_holders) | |
198 | queue = 1; | |
199 | break; | |
200 | default: | |
201 | BUG(); | |
202 | } | |
203 | ||
204 | if (queue) | |
205 | __user_dlm_queue_lockres(lockres); | |
206 | } | |
207 | ||
208 | static void user_bast(void *opaque, int level) | |
209 | { | |
210 | struct user_lock_res *lockres = opaque; | |
211 | ||
212 | mlog(0, "Blocking AST fired for lockres %s. Blocking level %d\n", | |
213 | lockres->l_name, level); | |
214 | ||
215 | spin_lock(&lockres->l_lock); | |
216 | lockres->l_flags |= USER_LOCK_BLOCKED; | |
217 | if (level > lockres->l_blocking) | |
218 | lockres->l_blocking = level; | |
219 | ||
220 | __user_dlm_queue_lockres(lockres); | |
221 | spin_unlock(&lockres->l_lock); | |
222 | ||
223 | wake_up(&lockres->l_event); | |
224 | } | |
225 | ||
226 | static void user_unlock_ast(void *opaque, enum dlm_status status) | |
227 | { | |
228 | struct user_lock_res *lockres = opaque; | |
229 | ||
230 | mlog(0, "UNLOCK AST called on lock %s\n", lockres->l_name); | |
231 | ||
232 | if (status != DLM_NORMAL) | |
233 | mlog(ML_ERROR, "Dlm returns status %d\n", status); | |
234 | ||
235 | spin_lock(&lockres->l_lock); | |
236 | if (lockres->l_flags & USER_LOCK_IN_TEARDOWN) | |
237 | lockres->l_level = LKM_IVMODE; | |
238 | else { | |
239 | lockres->l_requested = LKM_IVMODE; /* cancel an | |
240 | * upconvert | |
241 | * request. */ | |
242 | lockres->l_flags &= ~USER_LOCK_IN_CANCEL; | |
243 | /* we want the unblock thread to look at it again | |
244 | * now. */ | |
245 | __user_dlm_queue_lockres(lockres); | |
246 | } | |
247 | ||
248 | lockres->l_flags &= ~USER_LOCK_BUSY; | |
249 | spin_unlock(&lockres->l_lock); | |
250 | ||
251 | wake_up(&lockres->l_event); | |
252 | } | |
253 | ||
254 | static inline void user_dlm_drop_inode_ref(struct user_lock_res *lockres) | |
255 | { | |
256 | struct inode *inode; | |
257 | inode = user_dlm_inode_from_user_lockres(lockres); | |
258 | iput(inode); | |
259 | } | |
260 | ||
261 | static void user_dlm_unblock_lock(void *opaque) | |
262 | { | |
263 | int new_level, status; | |
264 | struct user_lock_res *lockres = (struct user_lock_res *) opaque; | |
265 | struct dlm_ctxt *dlm = dlm_ctxt_from_user_lockres(lockres); | |
266 | ||
267 | mlog(0, "processing lockres %s\n", lockres->l_name); | |
268 | ||
269 | spin_lock(&lockres->l_lock); | |
270 | ||
271 | BUG_ON(!(lockres->l_flags & USER_LOCK_BLOCKED)); | |
272 | BUG_ON(!(lockres->l_flags & USER_LOCK_QUEUED)); | |
273 | ||
274 | /* notice that we don't clear USER_LOCK_BLOCKED here. That's | |
275 | * for user_ast to do. */ | |
276 | lockres->l_flags &= ~USER_LOCK_QUEUED; | |
277 | ||
278 | if (lockres->l_flags & USER_LOCK_IN_TEARDOWN) { | |
279 | mlog(0, "lock is in teardown so we do nothing\n"); | |
280 | spin_unlock(&lockres->l_lock); | |
281 | goto drop_ref; | |
282 | } | |
283 | ||
284 | if (lockres->l_flags & USER_LOCK_BUSY) { | |
285 | mlog(0, "BUSY flag detected...\n"); | |
286 | if (lockres->l_flags & USER_LOCK_IN_CANCEL) { | |
287 | spin_unlock(&lockres->l_lock); | |
288 | goto drop_ref; | |
289 | } | |
290 | ||
291 | lockres->l_flags |= USER_LOCK_IN_CANCEL; | |
292 | spin_unlock(&lockres->l_lock); | |
293 | ||
294 | status = dlmunlock(dlm, | |
295 | &lockres->l_lksb, | |
296 | LKM_CANCEL, | |
297 | user_unlock_ast, | |
298 | lockres); | |
299 | if (status == DLM_CANCELGRANT) { | |
300 | /* If we got this, then the ast was fired | |
301 | * before we could cancel. We cleanup our | |
302 | * state, and restart the function. */ | |
303 | spin_lock(&lockres->l_lock); | |
304 | lockres->l_flags &= ~USER_LOCK_IN_CANCEL; | |
305 | spin_unlock(&lockres->l_lock); | |
306 | } else if (status != DLM_NORMAL) | |
307 | user_log_dlm_error("dlmunlock", status, lockres); | |
308 | goto drop_ref; | |
309 | } | |
310 | ||
311 | /* If there are still incompat holders, we can exit safely | |
312 | * without worrying about re-queueing this lock as that will | |
313 | * happen on the last call to user_cluster_unlock. */ | |
314 | if ((lockres->l_blocking == LKM_EXMODE) | |
315 | && (lockres->l_ex_holders || lockres->l_ro_holders)) { | |
316 | spin_unlock(&lockres->l_lock); | |
317 | mlog(0, "can't downconvert for ex: ro = %u, ex = %u\n", | |
318 | lockres->l_ro_holders, lockres->l_ex_holders); | |
319 | goto drop_ref; | |
320 | } | |
321 | ||
322 | if ((lockres->l_blocking == LKM_PRMODE) | |
323 | && lockres->l_ex_holders) { | |
324 | spin_unlock(&lockres->l_lock); | |
325 | mlog(0, "can't downconvert for pr: ex = %u\n", | |
326 | lockres->l_ex_holders); | |
327 | goto drop_ref; | |
328 | } | |
329 | ||
330 | /* yay, we can downconvert now. */ | |
331 | new_level = user_highest_compat_lock_level(lockres->l_blocking); | |
332 | lockres->l_requested = new_level; | |
333 | lockres->l_flags |= USER_LOCK_BUSY; | |
334 | mlog(0, "Downconvert lock from %d to %d\n", | |
335 | lockres->l_level, new_level); | |
336 | spin_unlock(&lockres->l_lock); | |
337 | ||
338 | /* need lock downconvert request now... */ | |
339 | status = dlmlock(dlm, | |
340 | new_level, | |
341 | &lockres->l_lksb, | |
342 | LKM_CONVERT|LKM_VALBLK, | |
343 | lockres->l_name, | |
344 | user_ast, | |
345 | lockres, | |
346 | user_bast); | |
347 | if (status != DLM_NORMAL) { | |
348 | user_log_dlm_error("dlmlock", status, lockres); | |
349 | user_recover_from_dlm_error(lockres); | |
350 | } | |
351 | ||
352 | drop_ref: | |
353 | user_dlm_drop_inode_ref(lockres); | |
354 | } | |
355 | ||
356 | static inline void user_dlm_inc_holders(struct user_lock_res *lockres, | |
357 | int level) | |
358 | { | |
359 | switch(level) { | |
360 | case LKM_EXMODE: | |
361 | lockres->l_ex_holders++; | |
362 | break; | |
363 | case LKM_PRMODE: | |
364 | lockres->l_ro_holders++; | |
365 | break; | |
366 | default: | |
367 | BUG(); | |
368 | } | |
369 | } | |
370 | ||
371 | /* predict what lock level we'll be dropping down to on behalf | |
372 | * of another node, and return true if the currently wanted | |
373 | * level will be compatible with it. */ | |
374 | static inline int | |
375 | user_may_continue_on_blocked_lock(struct user_lock_res *lockres, | |
376 | int wanted) | |
377 | { | |
378 | BUG_ON(!(lockres->l_flags & USER_LOCK_BLOCKED)); | |
379 | ||
380 | return wanted <= user_highest_compat_lock_level(lockres->l_blocking); | |
381 | } | |
382 | ||
383 | int user_dlm_cluster_lock(struct user_lock_res *lockres, | |
384 | int level, | |
385 | int lkm_flags) | |
386 | { | |
387 | int status, local_flags; | |
388 | struct dlm_ctxt *dlm = dlm_ctxt_from_user_lockres(lockres); | |
389 | ||
390 | if (level != LKM_EXMODE && | |
391 | level != LKM_PRMODE) { | |
392 | mlog(ML_ERROR, "lockres %s: invalid request!\n", | |
393 | lockres->l_name); | |
394 | status = -EINVAL; | |
395 | goto bail; | |
396 | } | |
397 | ||
398 | mlog(0, "lockres %s: asking for %s lock, passed flags = 0x%x\n", | |
399 | lockres->l_name, | |
400 | (level == LKM_EXMODE) ? "LKM_EXMODE" : "LKM_PRMODE", | |
401 | lkm_flags); | |
402 | ||
403 | again: | |
404 | if (signal_pending(current)) { | |
405 | status = -ERESTARTSYS; | |
406 | goto bail; | |
407 | } | |
408 | ||
409 | spin_lock(&lockres->l_lock); | |
410 | ||
411 | /* We only compare against the currently granted level | |
412 | * here. If the lock is blocked waiting on a downconvert, | |
413 | * we'll get caught below. */ | |
414 | if ((lockres->l_flags & USER_LOCK_BUSY) && | |
415 | (level > lockres->l_level)) { | |
416 | /* is someone sitting in dlm_lock? If so, wait on | |
417 | * them. */ | |
418 | spin_unlock(&lockres->l_lock); | |
419 | ||
420 | user_wait_on_busy_lock(lockres); | |
421 | goto again; | |
422 | } | |
423 | ||
424 | if ((lockres->l_flags & USER_LOCK_BLOCKED) && | |
425 | (!user_may_continue_on_blocked_lock(lockres, level))) { | |
426 | /* is the lock is currently blocked on behalf of | |
427 | * another node */ | |
428 | spin_unlock(&lockres->l_lock); | |
429 | ||
430 | user_wait_on_blocked_lock(lockres); | |
431 | goto again; | |
432 | } | |
433 | ||
434 | if (level > lockres->l_level) { | |
435 | local_flags = lkm_flags | LKM_VALBLK; | |
436 | if (lockres->l_level != LKM_IVMODE) | |
437 | local_flags |= LKM_CONVERT; | |
438 | ||
439 | lockres->l_requested = level; | |
440 | lockres->l_flags |= USER_LOCK_BUSY; | |
441 | spin_unlock(&lockres->l_lock); | |
442 | ||
443 | BUG_ON(level == LKM_IVMODE); | |
444 | BUG_ON(level == LKM_NLMODE); | |
445 | ||
446 | mlog(0, "lock %s, get lock from %d to level = %d\n", | |
447 | lockres->l_name, lockres->l_level, level); | |
448 | ||
449 | /* call dlm_lock to upgrade lock now */ | |
450 | status = dlmlock(dlm, | |
451 | level, | |
452 | &lockres->l_lksb, | |
453 | local_flags, | |
454 | lockres->l_name, | |
455 | user_ast, | |
456 | lockres, | |
457 | user_bast); | |
458 | if (status != DLM_NORMAL) { | |
459 | if ((lkm_flags & LKM_NOQUEUE) && | |
460 | (status == DLM_NOTQUEUED)) | |
461 | status = -EAGAIN; | |
462 | else { | |
463 | user_log_dlm_error("dlmlock", status, lockres); | |
464 | status = -EINVAL; | |
465 | } | |
466 | user_recover_from_dlm_error(lockres); | |
467 | goto bail; | |
468 | } | |
469 | ||
470 | mlog(0, "lock %s, successfull return from dlmlock\n", | |
471 | lockres->l_name); | |
472 | ||
473 | user_wait_on_busy_lock(lockres); | |
474 | goto again; | |
475 | } | |
476 | ||
477 | user_dlm_inc_holders(lockres, level); | |
478 | spin_unlock(&lockres->l_lock); | |
479 | ||
480 | mlog(0, "lockres %s: Got %s lock!\n", lockres->l_name, | |
481 | (level == LKM_EXMODE) ? "LKM_EXMODE" : "LKM_PRMODE"); | |
482 | ||
483 | status = 0; | |
484 | bail: | |
485 | return status; | |
486 | } | |
487 | ||
488 | static inline void user_dlm_dec_holders(struct user_lock_res *lockres, | |
489 | int level) | |
490 | { | |
491 | switch(level) { | |
492 | case LKM_EXMODE: | |
493 | BUG_ON(!lockres->l_ex_holders); | |
494 | lockres->l_ex_holders--; | |
495 | break; | |
496 | case LKM_PRMODE: | |
497 | BUG_ON(!lockres->l_ro_holders); | |
498 | lockres->l_ro_holders--; | |
499 | break; | |
500 | default: | |
501 | BUG(); | |
502 | } | |
503 | } | |
504 | ||
505 | void user_dlm_cluster_unlock(struct user_lock_res *lockres, | |
506 | int level) | |
507 | { | |
508 | if (level != LKM_EXMODE && | |
509 | level != LKM_PRMODE) { | |
510 | mlog(ML_ERROR, "lockres %s: invalid request!\n", lockres->l_name); | |
511 | return; | |
512 | } | |
513 | ||
514 | mlog(0, "lockres %s: dropping %s lock\n", lockres->l_name, | |
515 | (level == LKM_EXMODE) ? "LKM_EXMODE" : "LKM_PRMODE"); | |
516 | ||
517 | spin_lock(&lockres->l_lock); | |
518 | user_dlm_dec_holders(lockres, level); | |
519 | __user_dlm_cond_queue_lockres(lockres); | |
520 | spin_unlock(&lockres->l_lock); | |
521 | } | |
522 | ||
523 | void user_dlm_write_lvb(struct inode *inode, | |
524 | const char *val, | |
525 | unsigned int len) | |
526 | { | |
527 | struct user_lock_res *lockres = &DLMFS_I(inode)->ip_lockres; | |
528 | char *lvb = lockres->l_lksb.lvb; | |
529 | ||
530 | BUG_ON(len > DLM_LVB_LEN); | |
531 | ||
532 | spin_lock(&lockres->l_lock); | |
533 | ||
534 | BUG_ON(lockres->l_level < LKM_EXMODE); | |
535 | memcpy(lvb, val, len); | |
536 | ||
537 | spin_unlock(&lockres->l_lock); | |
538 | } | |
539 | ||
540 | void user_dlm_read_lvb(struct inode *inode, | |
541 | char *val, | |
542 | unsigned int len) | |
543 | { | |
544 | struct user_lock_res *lockres = &DLMFS_I(inode)->ip_lockres; | |
545 | char *lvb = lockres->l_lksb.lvb; | |
546 | ||
547 | BUG_ON(len > DLM_LVB_LEN); | |
548 | ||
549 | spin_lock(&lockres->l_lock); | |
550 | ||
551 | BUG_ON(lockres->l_level < LKM_PRMODE); | |
552 | memcpy(val, lvb, len); | |
553 | ||
554 | spin_unlock(&lockres->l_lock); | |
555 | } | |
556 | ||
557 | void user_dlm_lock_res_init(struct user_lock_res *lockres, | |
558 | struct dentry *dentry) | |
559 | { | |
560 | memset(lockres, 0, sizeof(*lockres)); | |
561 | ||
562 | spin_lock_init(&lockres->l_lock); | |
563 | init_waitqueue_head(&lockres->l_event); | |
564 | lockres->l_level = LKM_IVMODE; | |
565 | lockres->l_requested = LKM_IVMODE; | |
566 | lockres->l_blocking = LKM_IVMODE; | |
567 | ||
568 | /* should have been checked before getting here. */ | |
569 | BUG_ON(dentry->d_name.len >= USER_DLM_LOCK_ID_MAX_LEN); | |
570 | ||
571 | memcpy(lockres->l_name, | |
572 | dentry->d_name.name, | |
573 | dentry->d_name.len); | |
574 | } | |
575 | ||
576 | int user_dlm_destroy_lock(struct user_lock_res *lockres) | |
577 | { | |
578 | int status = -EBUSY; | |
579 | struct dlm_ctxt *dlm = dlm_ctxt_from_user_lockres(lockres); | |
580 | ||
581 | mlog(0, "asked to destroy %s\n", lockres->l_name); | |
582 | ||
583 | spin_lock(&lockres->l_lock); | |
584 | while (lockres->l_flags & USER_LOCK_BUSY) { | |
585 | spin_unlock(&lockres->l_lock); | |
586 | ||
587 | mlog(0, "lock %s is busy\n", lockres->l_name); | |
588 | ||
589 | user_wait_on_busy_lock(lockres); | |
590 | ||
591 | spin_lock(&lockres->l_lock); | |
592 | } | |
593 | ||
594 | if (lockres->l_ro_holders || lockres->l_ex_holders) { | |
595 | spin_unlock(&lockres->l_lock); | |
596 | mlog(0, "lock %s has holders\n", lockres->l_name); | |
597 | goto bail; | |
598 | } | |
599 | ||
600 | status = 0; | |
601 | if (!(lockres->l_flags & USER_LOCK_ATTACHED)) { | |
602 | spin_unlock(&lockres->l_lock); | |
603 | mlog(0, "lock %s is not attached\n", lockres->l_name); | |
604 | goto bail; | |
605 | } | |
606 | ||
607 | lockres->l_flags &= ~USER_LOCK_ATTACHED; | |
608 | lockres->l_flags |= USER_LOCK_BUSY; | |
609 | lockres->l_flags |= USER_LOCK_IN_TEARDOWN; | |
610 | spin_unlock(&lockres->l_lock); | |
611 | ||
612 | mlog(0, "unlocking lockres %s\n", lockres->l_name); | |
613 | status = dlmunlock(dlm, | |
614 | &lockres->l_lksb, | |
615 | LKM_VALBLK, | |
616 | user_unlock_ast, | |
617 | lockres); | |
618 | if (status != DLM_NORMAL) { | |
619 | user_log_dlm_error("dlmunlock", status, lockres); | |
620 | status = -EINVAL; | |
621 | goto bail; | |
622 | } | |
623 | ||
624 | user_wait_on_busy_lock(lockres); | |
625 | ||
626 | status = 0; | |
627 | bail: | |
628 | return status; | |
629 | } | |
630 | ||
631 | struct dlm_ctxt *user_dlm_register_context(struct qstr *name) | |
632 | { | |
633 | struct dlm_ctxt *dlm; | |
634 | u32 dlm_key; | |
635 | char *domain; | |
636 | ||
637 | domain = kmalloc(name->len + 1, GFP_KERNEL); | |
638 | if (!domain) { | |
639 | mlog_errno(-ENOMEM); | |
640 | return ERR_PTR(-ENOMEM); | |
641 | } | |
642 | ||
643 | dlm_key = crc32_le(0, name->name, name->len); | |
644 | ||
645 | snprintf(domain, name->len + 1, "%.*s", name->len, name->name); | |
646 | ||
647 | dlm = dlm_register_domain(domain, dlm_key); | |
648 | if (IS_ERR(dlm)) | |
649 | mlog_errno(PTR_ERR(dlm)); | |
650 | ||
651 | kfree(domain); | |
652 | return dlm; | |
653 | } | |
654 | ||
655 | void user_dlm_unregister_context(struct dlm_ctxt *dlm) | |
656 | { | |
657 | dlm_unregister_domain(dlm); | |
658 | } |