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1 | /* -*- mode: c; c-basic-offset: 8; -*- |
2 | * vim: noexpandtab sw=8 ts=8 sts=0: |
3 | * |
4 | * dlmmod.c |
5 | * |
6 | * standalone DLM module |
7 | * |
8 | * Copyright (C) 2004 Oracle. All rights reserved. |
9 | * |
10 | * This program is free software; you can redistribute it and/or |
11 | * modify it under the terms of the GNU General Public |
12 | * License as published by the Free Software Foundation; either |
13 | * version 2 of the License, or (at your option) any later version. |
14 | * |
15 | * This program is distributed in the hope that it will be useful, |
16 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
17 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
18 | * General Public License for more details. |
19 | * |
20 | * You should have received a copy of the GNU General Public |
21 | * License along with this program; if not, write to the |
22 | * Free Software Foundation, Inc., 59 Temple Place - Suite 330, |
23 | * Boston, MA 021110-1307, USA. |
24 | * |
25 | */ |
26 | |
27 | |
28 | #include <linux/module.h> |
29 | #include <linux/fs.h> |
30 | #include <linux/types.h> |
31 | #include <linux/slab.h> |
32 | #include <linux/highmem.h> |
33 | #include <linux/init.h> |
34 | #include <linux/sysctl.h> |
35 | #include <linux/random.h> |
36 | #include <linux/blkdev.h> |
37 | #include <linux/socket.h> |
38 | #include <linux/inet.h> |
39 | #include <linux/spinlock.h> |
40 | #include <linux/delay.h> |
41 | |
42 | |
43 | #include "cluster/heartbeat.h" |
44 | #include "cluster/nodemanager.h" |
45 | #include "cluster/tcp.h" |
46 | |
47 | #include "dlmapi.h" |
48 | #include "dlmcommon.h" |
49 | #include "dlmdomain.h" |
50 | #include "dlmdebug.h" |
51 | |
52 | #define MLOG_MASK_PREFIX (ML_DLM|ML_DLM_MASTER) |
53 | #include "cluster/masklog.h" |
54 | |
55 | static void dlm_mle_node_down(struct dlm_ctxt *dlm, |
56 | struct dlm_master_list_entry *mle, |
57 | struct o2nm_node *node, |
58 | int idx); |
59 | static void dlm_mle_node_up(struct dlm_ctxt *dlm, |
60 | struct dlm_master_list_entry *mle, |
61 | struct o2nm_node *node, |
62 | int idx); |
63 | |
64 | static void dlm_assert_master_worker(struct dlm_work_item *item, void *data); |
65 | static int dlm_do_assert_master(struct dlm_ctxt *dlm, |
66 | struct dlm_lock_resource *res, |
67 | void *nodemap, u32 flags); |
68 | static void dlm_deref_lockres_worker(struct dlm_work_item *item, void *data); |
69 | |
70 | static inline int dlm_mle_equal(struct dlm_ctxt *dlm, |
71 | struct dlm_master_list_entry *mle, |
72 | const char *name, |
73 | unsigned int namelen) |
74 | { |
75 | if (dlm != mle->dlm) |
76 | return 0; |
77 | |
78 | if (namelen != mle->mnamelen || |
79 | memcmp(name, mle->mname, namelen) != 0) |
80 | return 0; |
81 | |
82 | return 1; |
83 | } |
84 | |
85 | static struct kmem_cache *dlm_lockres_cache = NULL; |
86 | static struct kmem_cache *dlm_lockname_cache = NULL; |
87 | static struct kmem_cache *dlm_mle_cache = NULL; |
88 | |
89 | static void dlm_mle_release(struct kref *kref); |
90 | static void dlm_init_mle(struct dlm_master_list_entry *mle, |
91 | enum dlm_mle_type type, |
92 | struct dlm_ctxt *dlm, |
93 | struct dlm_lock_resource *res, |
94 | const char *name, |
95 | unsigned int namelen); |
96 | static void dlm_put_mle(struct dlm_master_list_entry *mle); |
97 | static void __dlm_put_mle(struct dlm_master_list_entry *mle); |
98 | static int dlm_find_mle(struct dlm_ctxt *dlm, |
99 | struct dlm_master_list_entry **mle, |
100 | char *name, unsigned int namelen); |
101 | |
102 | static int dlm_do_master_request(struct dlm_lock_resource *res, |
103 | struct dlm_master_list_entry *mle, int to); |
104 | |
105 | |
106 | static int dlm_wait_for_lock_mastery(struct dlm_ctxt *dlm, |
107 | struct dlm_lock_resource *res, |
108 | struct dlm_master_list_entry *mle, |
109 | int *blocked); |
110 | static int dlm_restart_lock_mastery(struct dlm_ctxt *dlm, |
111 | struct dlm_lock_resource *res, |
112 | struct dlm_master_list_entry *mle, |
113 | int blocked); |
114 | static int dlm_add_migration_mle(struct dlm_ctxt *dlm, |
115 | struct dlm_lock_resource *res, |
116 | struct dlm_master_list_entry *mle, |
117 | struct dlm_master_list_entry **oldmle, |
118 | const char *name, unsigned int namelen, |
119 | u8 new_master, u8 master); |
120 | |
121 | static u8 dlm_pick_migration_target(struct dlm_ctxt *dlm, |
122 | struct dlm_lock_resource *res); |
123 | static void dlm_remove_nonlocal_locks(struct dlm_ctxt *dlm, |
124 | struct dlm_lock_resource *res); |
125 | static int dlm_mark_lockres_migrating(struct dlm_ctxt *dlm, |
126 | struct dlm_lock_resource *res, |
127 | u8 target); |
128 | static int dlm_pre_master_reco_lockres(struct dlm_ctxt *dlm, |
129 | struct dlm_lock_resource *res); |
130 | |
131 | |
132 | int dlm_is_host_down(int errno) |
133 | { |
134 | switch (errno) { |
135 | case -EBADF: |
136 | case -ECONNREFUSED: |
137 | case -ENOTCONN: |
138 | case -ECONNRESET: |
139 | case -EPIPE: |
140 | case -EHOSTDOWN: |
141 | case -EHOSTUNREACH: |
142 | case -ETIMEDOUT: |
143 | case -ECONNABORTED: |
144 | case -ENETDOWN: |
145 | case -ENETUNREACH: |
146 | case -ENETRESET: |
147 | case -ESHUTDOWN: |
148 | case -ENOPROTOOPT: |
149 | case -EINVAL: /* if returned from our tcp code, |
150 | this means there is no socket */ |
151 | return 1; |
152 | } |
153 | return 0; |
154 | } |
155 | |
156 | |
157 | /* |
158 | * MASTER LIST FUNCTIONS |
159 | */ |
160 | |
161 | |
162 | /* |
163 | * regarding master list entries and heartbeat callbacks: |
164 | * |
165 | * in order to avoid sleeping and allocation that occurs in |
166 | * heartbeat, master list entries are simply attached to the |
167 | * dlm's established heartbeat callbacks. the mle is attached |
168 | * when it is created, and since the dlm->spinlock is held at |
169 | * that time, any heartbeat event will be properly discovered |
170 | * by the mle. the mle needs to be detached from the |
171 | * dlm->mle_hb_events list as soon as heartbeat events are no |
172 | * longer useful to the mle, and before the mle is freed. |
173 | * |
174 | * as a general rule, heartbeat events are no longer needed by |
175 | * the mle once an "answer" regarding the lock master has been |
176 | * received. |
177 | */ |
178 | static inline void __dlm_mle_attach_hb_events(struct dlm_ctxt *dlm, |
179 | struct dlm_master_list_entry *mle) |
180 | { |
181 | assert_spin_locked(&dlm->spinlock); |
182 | |
183 | list_add_tail(&mle->hb_events, &dlm->mle_hb_events); |
184 | } |
185 | |
186 | |
187 | static inline void __dlm_mle_detach_hb_events(struct dlm_ctxt *dlm, |
188 | struct dlm_master_list_entry *mle) |
189 | { |
190 | if (!list_empty(&mle->hb_events)) |
191 | list_del_init(&mle->hb_events); |
192 | } |
193 | |
194 | |
195 | static inline void dlm_mle_detach_hb_events(struct dlm_ctxt *dlm, |
196 | struct dlm_master_list_entry *mle) |
197 | { |
198 | spin_lock(&dlm->spinlock); |
199 | __dlm_mle_detach_hb_events(dlm, mle); |
200 | spin_unlock(&dlm->spinlock); |
201 | } |
202 | |
203 | static void dlm_get_mle_inuse(struct dlm_master_list_entry *mle) |
204 | { |
205 | struct dlm_ctxt *dlm; |
206 | dlm = mle->dlm; |
207 | |
208 | assert_spin_locked(&dlm->spinlock); |
209 | assert_spin_locked(&dlm->master_lock); |
210 | mle->inuse++; |
211 | kref_get(&mle->mle_refs); |
212 | } |
213 | |
214 | static void dlm_put_mle_inuse(struct dlm_master_list_entry *mle) |
215 | { |
216 | struct dlm_ctxt *dlm; |
217 | dlm = mle->dlm; |
218 | |
219 | spin_lock(&dlm->spinlock); |
220 | spin_lock(&dlm->master_lock); |
221 | mle->inuse--; |
222 | __dlm_put_mle(mle); |
223 | spin_unlock(&dlm->master_lock); |
224 | spin_unlock(&dlm->spinlock); |
225 | |
226 | } |
227 | |
228 | /* remove from list and free */ |
229 | static void __dlm_put_mle(struct dlm_master_list_entry *mle) |
230 | { |
231 | struct dlm_ctxt *dlm; |
232 | dlm = mle->dlm; |
233 | |
234 | assert_spin_locked(&dlm->spinlock); |
235 | assert_spin_locked(&dlm->master_lock); |
236 | if (!atomic_read(&mle->mle_refs.refcount)) { |
237 | /* this may or may not crash, but who cares. |
238 | * it's a BUG. */ |
239 | mlog(ML_ERROR, "bad mle: %p\n", mle); |
240 | dlm_print_one_mle(mle); |
241 | BUG(); |
242 | } else |
243 | kref_put(&mle->mle_refs, dlm_mle_release); |
244 | } |
245 | |
246 | |
247 | /* must not have any spinlocks coming in */ |
248 | static void dlm_put_mle(struct dlm_master_list_entry *mle) |
249 | { |
250 | struct dlm_ctxt *dlm; |
251 | dlm = mle->dlm; |
252 | |
253 | spin_lock(&dlm->spinlock); |
254 | spin_lock(&dlm->master_lock); |
255 | __dlm_put_mle(mle); |
256 | spin_unlock(&dlm->master_lock); |
257 | spin_unlock(&dlm->spinlock); |
258 | } |
259 | |
260 | static inline void dlm_get_mle(struct dlm_master_list_entry *mle) |
261 | { |
262 | kref_get(&mle->mle_refs); |
263 | } |
264 | |
265 | static void dlm_init_mle(struct dlm_master_list_entry *mle, |
266 | enum dlm_mle_type type, |
267 | struct dlm_ctxt *dlm, |
268 | struct dlm_lock_resource *res, |
269 | const char *name, |
270 | unsigned int namelen) |
271 | { |
272 | assert_spin_locked(&dlm->spinlock); |
273 | |
274 | mle->dlm = dlm; |
275 | mle->type = type; |
276 | INIT_HLIST_NODE(&mle->master_hash_node); |
277 | INIT_LIST_HEAD(&mle->hb_events); |
278 | memset(mle->maybe_map, 0, sizeof(mle->maybe_map)); |
279 | spin_lock_init(&mle->spinlock); |
280 | init_waitqueue_head(&mle->wq); |
281 | atomic_set(&mle->woken, 0); |
282 | kref_init(&mle->mle_refs); |
283 | memset(mle->response_map, 0, sizeof(mle->response_map)); |
284 | mle->master = O2NM_MAX_NODES; |
285 | mle->new_master = O2NM_MAX_NODES; |
286 | mle->inuse = 0; |
287 | |
288 | BUG_ON(mle->type != DLM_MLE_BLOCK && |
289 | mle->type != DLM_MLE_MASTER && |
290 | mle->type != DLM_MLE_MIGRATION); |
291 | |
292 | if (mle->type == DLM_MLE_MASTER) { |
293 | BUG_ON(!res); |
294 | mle->mleres = res; |
295 | memcpy(mle->mname, res->lockname.name, res->lockname.len); |
296 | mle->mnamelen = res->lockname.len; |
297 | mle->mnamehash = res->lockname.hash; |
298 | } else { |
299 | BUG_ON(!name); |
300 | mle->mleres = NULL; |
301 | memcpy(mle->mname, name, namelen); |
302 | mle->mnamelen = namelen; |
303 | mle->mnamehash = dlm_lockid_hash(name, namelen); |
304 | } |
305 | |
306 | atomic_inc(&dlm->mle_tot_count[mle->type]); |
307 | atomic_inc(&dlm->mle_cur_count[mle->type]); |
308 | |
309 | /* copy off the node_map and register hb callbacks on our copy */ |
310 | memcpy(mle->node_map, dlm->domain_map, sizeof(mle->node_map)); |
311 | memcpy(mle->vote_map, dlm->domain_map, sizeof(mle->vote_map)); |
312 | clear_bit(dlm->node_num, mle->vote_map); |
313 | clear_bit(dlm->node_num, mle->node_map); |
314 | |
315 | /* attach the mle to the domain node up/down events */ |
316 | __dlm_mle_attach_hb_events(dlm, mle); |
317 | } |
318 | |
319 | void __dlm_unlink_mle(struct dlm_ctxt *dlm, struct dlm_master_list_entry *mle) |
320 | { |
321 | assert_spin_locked(&dlm->spinlock); |
322 | assert_spin_locked(&dlm->master_lock); |
323 | |
324 | if (!hlist_unhashed(&mle->master_hash_node)) |
325 | hlist_del_init(&mle->master_hash_node); |
326 | } |
327 | |
328 | void __dlm_insert_mle(struct dlm_ctxt *dlm, struct dlm_master_list_entry *mle) |
329 | { |
330 | struct hlist_head *bucket; |
331 | |
332 | assert_spin_locked(&dlm->master_lock); |
333 | |
334 | bucket = dlm_master_hash(dlm, mle->mnamehash); |
335 | hlist_add_head(&mle->master_hash_node, bucket); |
336 | } |
337 | |
338 | /* returns 1 if found, 0 if not */ |
339 | static int dlm_find_mle(struct dlm_ctxt *dlm, |
340 | struct dlm_master_list_entry **mle, |
341 | char *name, unsigned int namelen) |
342 | { |
343 | struct dlm_master_list_entry *tmpmle; |
344 | struct hlist_head *bucket; |
345 | struct hlist_node *list; |
346 | unsigned int hash; |
347 | |
348 | assert_spin_locked(&dlm->master_lock); |
349 | |
350 | hash = dlm_lockid_hash(name, namelen); |
351 | bucket = dlm_master_hash(dlm, hash); |
352 | hlist_for_each(list, bucket) { |
353 | tmpmle = hlist_entry(list, struct dlm_master_list_entry, |
354 | master_hash_node); |
355 | if (!dlm_mle_equal(dlm, tmpmle, name, namelen)) |
356 | continue; |
357 | dlm_get_mle(tmpmle); |
358 | *mle = tmpmle; |
359 | return 1; |
360 | } |
361 | return 0; |
362 | } |
363 | |
364 | void dlm_hb_event_notify_attached(struct dlm_ctxt *dlm, int idx, int node_up) |
365 | { |
366 | struct dlm_master_list_entry *mle; |
367 | |
368 | assert_spin_locked(&dlm->spinlock); |
369 | |
370 | list_for_each_entry(mle, &dlm->mle_hb_events, hb_events) { |
371 | if (node_up) |
372 | dlm_mle_node_up(dlm, mle, NULL, idx); |
373 | else |
374 | dlm_mle_node_down(dlm, mle, NULL, idx); |
375 | } |
376 | } |
377 | |
378 | static void dlm_mle_node_down(struct dlm_ctxt *dlm, |
379 | struct dlm_master_list_entry *mle, |
380 | struct o2nm_node *node, int idx) |
381 | { |
382 | spin_lock(&mle->spinlock); |
383 | |
384 | if (!test_bit(idx, mle->node_map)) |
385 | mlog(0, "node %u already removed from nodemap!\n", idx); |
386 | else |
387 | clear_bit(idx, mle->node_map); |
388 | |
389 | spin_unlock(&mle->spinlock); |
390 | } |
391 | |
392 | static void dlm_mle_node_up(struct dlm_ctxt *dlm, |
393 | struct dlm_master_list_entry *mle, |
394 | struct o2nm_node *node, int idx) |
395 | { |
396 | spin_lock(&mle->spinlock); |
397 | |
398 | if (test_bit(idx, mle->node_map)) |
399 | mlog(0, "node %u already in node map!\n", idx); |
400 | else |
401 | set_bit(idx, mle->node_map); |
402 | |
403 | spin_unlock(&mle->spinlock); |
404 | } |
405 | |
406 | |
407 | int dlm_init_mle_cache(void) |
408 | { |
409 | dlm_mle_cache = kmem_cache_create("o2dlm_mle", |
410 | sizeof(struct dlm_master_list_entry), |
411 | 0, SLAB_HWCACHE_ALIGN, |
412 | NULL); |
413 | if (dlm_mle_cache == NULL) |
414 | return -ENOMEM; |
415 | return 0; |
416 | } |
417 | |
418 | void dlm_destroy_mle_cache(void) |
419 | { |
420 | if (dlm_mle_cache) |
421 | kmem_cache_destroy(dlm_mle_cache); |
422 | } |
423 | |
424 | static void dlm_mle_release(struct kref *kref) |
425 | { |
426 | struct dlm_master_list_entry *mle; |
427 | struct dlm_ctxt *dlm; |
428 | |
429 | mlog_entry_void(); |
430 | |
431 | mle = container_of(kref, struct dlm_master_list_entry, mle_refs); |
432 | dlm = mle->dlm; |
433 | |
434 | assert_spin_locked(&dlm->spinlock); |
435 | assert_spin_locked(&dlm->master_lock); |
436 | |
437 | mlog(0, "Releasing mle for %.*s, type %d\n", mle->mnamelen, mle->mname, |
438 | mle->type); |
439 | |
440 | /* remove from list if not already */ |
441 | __dlm_unlink_mle(dlm, mle); |
442 | |
443 | /* detach the mle from the domain node up/down events */ |
444 | __dlm_mle_detach_hb_events(dlm, mle); |
445 | |
446 | atomic_dec(&dlm->mle_cur_count[mle->type]); |
447 | |
448 | /* NOTE: kfree under spinlock here. |
449 | * if this is bad, we can move this to a freelist. */ |
450 | kmem_cache_free(dlm_mle_cache, mle); |
451 | } |
452 | |
453 | |
454 | /* |
455 | * LOCK RESOURCE FUNCTIONS |
456 | */ |
457 | |
458 | int dlm_init_master_caches(void) |
459 | { |
460 | dlm_lockres_cache = kmem_cache_create("o2dlm_lockres", |
461 | sizeof(struct dlm_lock_resource), |
462 | 0, SLAB_HWCACHE_ALIGN, NULL); |
463 | if (!dlm_lockres_cache) |
464 | goto bail; |
465 | |
466 | dlm_lockname_cache = kmem_cache_create("o2dlm_lockname", |
467 | DLM_LOCKID_NAME_MAX, 0, |
468 | SLAB_HWCACHE_ALIGN, NULL); |
469 | if (!dlm_lockname_cache) |
470 | goto bail; |
471 | |
472 | return 0; |
473 | bail: |
474 | dlm_destroy_master_caches(); |
475 | return -ENOMEM; |
476 | } |
477 | |
478 | void dlm_destroy_master_caches(void) |
479 | { |
480 | if (dlm_lockname_cache) |
481 | kmem_cache_destroy(dlm_lockname_cache); |
482 | |
483 | if (dlm_lockres_cache) |
484 | kmem_cache_destroy(dlm_lockres_cache); |
485 | } |
486 | |
487 | static void dlm_lockres_release(struct kref *kref) |
488 | { |
489 | struct dlm_lock_resource *res; |
490 | struct dlm_ctxt *dlm; |
491 | |
492 | res = container_of(kref, struct dlm_lock_resource, refs); |
493 | dlm = res->dlm; |
494 | |
495 | /* This should not happen -- all lockres' have a name |
496 | * associated with them at init time. */ |
497 | BUG_ON(!res->lockname.name); |
498 | |
499 | mlog(0, "destroying lockres %.*s\n", res->lockname.len, |
500 | res->lockname.name); |
501 | |
502 | spin_lock(&dlm->track_lock); |
503 | if (!list_empty(&res->tracking)) |
504 | list_del_init(&res->tracking); |
505 | else { |
506 | mlog(ML_ERROR, "Resource %.*s not on the Tracking list\n", |
507 | res->lockname.len, res->lockname.name); |
508 | dlm_print_one_lock_resource(res); |
509 | } |
510 | spin_unlock(&dlm->track_lock); |
511 | |
512 | atomic_dec(&dlm->res_cur_count); |
513 | |
514 | dlm_put(dlm); |
515 | |
516 | if (!hlist_unhashed(&res->hash_node) || |
517 | !list_empty(&res->granted) || |
518 | !list_empty(&res->converting) || |
519 | !list_empty(&res->blocked) || |
520 | !list_empty(&res->dirty) || |
521 | !list_empty(&res->recovering) || |
522 | !list_empty(&res->purge)) { |
523 | mlog(ML_ERROR, |
524 | "Going to BUG for resource %.*s." |
525 | " We're on a list! [%c%c%c%c%c%c%c]\n", |
526 | res->lockname.len, res->lockname.name, |
527 | !hlist_unhashed(&res->hash_node) ? 'H' : ' ', |
528 | !list_empty(&res->granted) ? 'G' : ' ', |
529 | !list_empty(&res->converting) ? 'C' : ' ', |
530 | !list_empty(&res->blocked) ? 'B' : ' ', |
531 | !list_empty(&res->dirty) ? 'D' : ' ', |
532 | !list_empty(&res->recovering) ? 'R' : ' ', |
533 | !list_empty(&res->purge) ? 'P' : ' '); |
534 | |
535 | dlm_print_one_lock_resource(res); |
536 | } |
537 | |
538 | /* By the time we're ready to blow this guy away, we shouldn't |
539 | * be on any lists. */ |
540 | BUG_ON(!hlist_unhashed(&res->hash_node)); |
541 | BUG_ON(!list_empty(&res->granted)); |
542 | BUG_ON(!list_empty(&res->converting)); |
543 | BUG_ON(!list_empty(&res->blocked)); |
544 | BUG_ON(!list_empty(&res->dirty)); |
545 | BUG_ON(!list_empty(&res->recovering)); |
546 | BUG_ON(!list_empty(&res->purge)); |
547 | |
548 | kmem_cache_free(dlm_lockname_cache, (void *)res->lockname.name); |
549 | |
550 | kmem_cache_free(dlm_lockres_cache, res); |
551 | } |
552 | |
553 | void dlm_lockres_put(struct dlm_lock_resource *res) |
554 | { |
555 | kref_put(&res->refs, dlm_lockres_release); |
556 | } |
557 | |
558 | static void dlm_init_lockres(struct dlm_ctxt *dlm, |
559 | struct dlm_lock_resource *res, |
560 | const char *name, unsigned int namelen) |
561 | { |
562 | char *qname; |
563 | |
564 | /* If we memset here, we lose our reference to the kmalloc'd |
565 | * res->lockname.name, so be sure to init every field |
566 | * correctly! */ |
567 | |
568 | qname = (char *) res->lockname.name; |
569 | memcpy(qname, name, namelen); |
570 | |
571 | res->lockname.len = namelen; |
572 | res->lockname.hash = dlm_lockid_hash(name, namelen); |
573 | |
574 | init_waitqueue_head(&res->wq); |
575 | spin_lock_init(&res->spinlock); |
576 | INIT_HLIST_NODE(&res->hash_node); |
577 | INIT_LIST_HEAD(&res->granted); |
578 | INIT_LIST_HEAD(&res->converting); |
579 | INIT_LIST_HEAD(&res->blocked); |
580 | INIT_LIST_HEAD(&res->dirty); |
581 | INIT_LIST_HEAD(&res->recovering); |
582 | INIT_LIST_HEAD(&res->purge); |
583 | INIT_LIST_HEAD(&res->tracking); |
584 | atomic_set(&res->asts_reserved, 0); |
585 | res->migration_pending = 0; |
586 | res->inflight_locks = 0; |
587 | |
588 | /* put in dlm_lockres_release */ |
589 | dlm_grab(dlm); |
590 | res->dlm = dlm; |
591 | |
592 | kref_init(&res->refs); |
593 | |
594 | atomic_inc(&dlm->res_tot_count); |
595 | atomic_inc(&dlm->res_cur_count); |
596 | |
597 | /* just for consistency */ |
598 | spin_lock(&res->spinlock); |
599 | dlm_set_lockres_owner(dlm, res, DLM_LOCK_RES_OWNER_UNKNOWN); |
600 | spin_unlock(&res->spinlock); |
601 | |
602 | res->state = DLM_LOCK_RES_IN_PROGRESS; |
603 | |
604 | res->last_used = 0; |
605 | |
606 | spin_lock(&dlm->spinlock); |
607 | list_add_tail(&res->tracking, &dlm->tracking_list); |
608 | spin_unlock(&dlm->spinlock); |
609 | |
610 | memset(res->lvb, 0, DLM_LVB_LEN); |
611 | memset(res->refmap, 0, sizeof(res->refmap)); |
612 | } |
613 | |
614 | struct dlm_lock_resource *dlm_new_lockres(struct dlm_ctxt *dlm, |
615 | const char *name, |
616 | unsigned int namelen) |
617 | { |
618 | struct dlm_lock_resource *res = NULL; |
619 | |
620 | res = (struct dlm_lock_resource *) |
621 | kmem_cache_zalloc(dlm_lockres_cache, GFP_NOFS); |
622 | if (!res) |
623 | goto error; |
624 | |
625 | res->lockname.name = (char *) |
626 | kmem_cache_zalloc(dlm_lockname_cache, GFP_NOFS); |
627 | if (!res->lockname.name) |
628 | goto error; |
629 | |
630 | dlm_init_lockres(dlm, res, name, namelen); |
631 | return res; |
632 | |
633 | error: |
634 | if (res && res->lockname.name) |
635 | kmem_cache_free(dlm_lockname_cache, (void *)res->lockname.name); |
636 | |
637 | if (res) |
638 | kmem_cache_free(dlm_lockres_cache, res); |
639 | return NULL; |
640 | } |
641 | |
642 | void __dlm_lockres_grab_inflight_ref(struct dlm_ctxt *dlm, |
643 | struct dlm_lock_resource *res, |
644 | int new_lockres, |
645 | const char *file, |
646 | int line) |
647 | { |
648 | if (!new_lockres) |
649 | assert_spin_locked(&res->spinlock); |
650 | |
651 | if (!test_bit(dlm->node_num, res->refmap)) { |
652 | BUG_ON(res->inflight_locks != 0); |
653 | dlm_lockres_set_refmap_bit(dlm->node_num, res); |
654 | } |
655 | res->inflight_locks++; |
656 | mlog(0, "%s:%.*s: inflight++: now %u\n", |
657 | dlm->name, res->lockname.len, res->lockname.name, |
658 | res->inflight_locks); |
659 | } |
660 | |
661 | void __dlm_lockres_drop_inflight_ref(struct dlm_ctxt *dlm, |
662 | struct dlm_lock_resource *res, |
663 | const char *file, |
664 | int line) |
665 | { |
666 | assert_spin_locked(&res->spinlock); |
667 | |
668 | BUG_ON(res->inflight_locks == 0); |
669 | res->inflight_locks--; |
670 | mlog(0, "%s:%.*s: inflight--: now %u\n", |
671 | dlm->name, res->lockname.len, res->lockname.name, |
672 | res->inflight_locks); |
673 | if (res->inflight_locks == 0) |
674 | dlm_lockres_clear_refmap_bit(dlm->node_num, res); |
675 | wake_up(&res->wq); |
676 | } |
677 | |
678 | /* |
679 | * lookup a lock resource by name. |
680 | * may already exist in the hashtable. |
681 | * lockid is null terminated |
682 | * |
683 | * if not, allocate enough for the lockres and for |
684 | * the temporary structure used in doing the mastering. |
685 | * |
686 | * also, do a lookup in the dlm->master_list to see |
687 | * if another node has begun mastering the same lock. |
688 | * if so, there should be a block entry in there |
689 | * for this name, and we should *not* attempt to master |
690 | * the lock here. need to wait around for that node |
691 | * to assert_master (or die). |
692 | * |
693 | */ |
694 | struct dlm_lock_resource * dlm_get_lock_resource(struct dlm_ctxt *dlm, |
695 | const char *lockid, |
696 | int namelen, |
697 | int flags) |
698 | { |
699 | struct dlm_lock_resource *tmpres=NULL, *res=NULL; |
700 | struct dlm_master_list_entry *mle = NULL; |
701 | struct dlm_master_list_entry *alloc_mle = NULL; |
702 | int blocked = 0; |
703 | int ret, nodenum; |
704 | struct dlm_node_iter iter; |
705 | unsigned int hash; |
706 | int tries = 0; |
707 | int bit, wait_on_recovery = 0; |
708 | int drop_inflight_if_nonlocal = 0; |
709 | |
710 | BUG_ON(!lockid); |
711 | |
712 | hash = dlm_lockid_hash(lockid, namelen); |
713 | |
714 | mlog(0, "get lockres %s (len %d)\n", lockid, namelen); |
715 | |
716 | lookup: |
717 | spin_lock(&dlm->spinlock); |
718 | tmpres = __dlm_lookup_lockres_full(dlm, lockid, namelen, hash); |
719 | if (tmpres) { |
720 | int dropping_ref = 0; |
721 | |
722 | spin_unlock(&dlm->spinlock); |
723 | |
724 | spin_lock(&tmpres->spinlock); |
725 | /* We wait for the other thread that is mastering the resource */ |
726 | if (tmpres->owner == DLM_LOCK_RES_OWNER_UNKNOWN) { |
727 | __dlm_wait_on_lockres(tmpres); |
728 | BUG_ON(tmpres->owner == DLM_LOCK_RES_OWNER_UNKNOWN); |
729 | } |
730 | |
731 | if (tmpres->owner == dlm->node_num) { |
732 | BUG_ON(tmpres->state & DLM_LOCK_RES_DROPPING_REF); |
733 | dlm_lockres_grab_inflight_ref(dlm, tmpres); |
734 | } else if (tmpres->state & DLM_LOCK_RES_DROPPING_REF) |
735 | dropping_ref = 1; |
736 | spin_unlock(&tmpres->spinlock); |
737 | |
738 | /* wait until done messaging the master, drop our ref to allow |
739 | * the lockres to be purged, start over. */ |
740 | if (dropping_ref) { |
741 | spin_lock(&tmpres->spinlock); |
742 | __dlm_wait_on_lockres_flags(tmpres, DLM_LOCK_RES_DROPPING_REF); |
743 | spin_unlock(&tmpres->spinlock); |
744 | dlm_lockres_put(tmpres); |
745 | tmpres = NULL; |
746 | goto lookup; |
747 | } |
748 | |
749 | mlog(0, "found in hash!\n"); |
750 | if (res) |
751 | dlm_lockres_put(res); |
752 | res = tmpres; |
753 | goto leave; |
754 | } |
755 | |
756 | if (!res) { |
757 | spin_unlock(&dlm->spinlock); |
758 | mlog(0, "allocating a new resource\n"); |
759 | /* nothing found and we need to allocate one. */ |
760 | alloc_mle = (struct dlm_master_list_entry *) |
761 | kmem_cache_alloc(dlm_mle_cache, GFP_NOFS); |
762 | if (!alloc_mle) |
763 | goto leave; |
764 | res = dlm_new_lockres(dlm, lockid, namelen); |
765 | if (!res) |
766 | goto leave; |
767 | goto lookup; |
768 | } |
769 | |
770 | mlog(0, "no lockres found, allocated our own: %p\n", res); |
771 | |
772 | if (flags & LKM_LOCAL) { |
773 | /* caller knows it's safe to assume it's not mastered elsewhere |
774 | * DONE! return right away */ |
775 | spin_lock(&res->spinlock); |
776 | dlm_change_lockres_owner(dlm, res, dlm->node_num); |
777 | __dlm_insert_lockres(dlm, res); |
778 | dlm_lockres_grab_inflight_ref(dlm, res); |
779 | spin_unlock(&res->spinlock); |
780 | spin_unlock(&dlm->spinlock); |
781 | /* lockres still marked IN_PROGRESS */ |
782 | goto wake_waiters; |
783 | } |
784 | |
785 | /* check master list to see if another node has started mastering it */ |
786 | spin_lock(&dlm->master_lock); |
787 | |
788 | /* if we found a block, wait for lock to be mastered by another node */ |
789 | blocked = dlm_find_mle(dlm, &mle, (char *)lockid, namelen); |
790 | if (blocked) { |
791 | int mig; |
792 | if (mle->type == DLM_MLE_MASTER) { |
793 | mlog(ML_ERROR, "master entry for nonexistent lock!\n"); |
794 | BUG(); |
795 | } |
796 | mig = (mle->type == DLM_MLE_MIGRATION); |
797 | /* if there is a migration in progress, let the migration |
798 | * finish before continuing. we can wait for the absence |
799 | * of the MIGRATION mle: either the migrate finished or |
800 | * one of the nodes died and the mle was cleaned up. |
801 | * if there is a BLOCK here, but it already has a master |
802 | * set, we are too late. the master does not have a ref |
803 | * for us in the refmap. detach the mle and drop it. |
804 | * either way, go back to the top and start over. */ |
805 | if (mig || mle->master != O2NM_MAX_NODES) { |
806 | BUG_ON(mig && mle->master == dlm->node_num); |
807 | /* we arrived too late. the master does not |
808 | * have a ref for us. retry. */ |
809 | mlog(0, "%s:%.*s: late on %s\n", |
810 | dlm->name, namelen, lockid, |
811 | mig ? "MIGRATION" : "BLOCK"); |
812 | spin_unlock(&dlm->master_lock); |
813 | spin_unlock(&dlm->spinlock); |
814 | |
815 | /* master is known, detach */ |
816 | if (!mig) |
817 | dlm_mle_detach_hb_events(dlm, mle); |
818 | dlm_put_mle(mle); |
819 | mle = NULL; |
820 | /* this is lame, but we cant wait on either |
821 | * the mle or lockres waitqueue here */ |
822 | if (mig) |
823 | msleep(100); |
824 | goto lookup; |
825 | } |
826 | } else { |
827 | /* go ahead and try to master lock on this node */ |
828 | mle = alloc_mle; |
829 | /* make sure this does not get freed below */ |
830 | alloc_mle = NULL; |
831 | dlm_init_mle(mle, DLM_MLE_MASTER, dlm, res, NULL, 0); |
832 | set_bit(dlm->node_num, mle->maybe_map); |
833 | __dlm_insert_mle(dlm, mle); |
834 | |
835 | /* still holding the dlm spinlock, check the recovery map |
836 | * to see if there are any nodes that still need to be |
837 | * considered. these will not appear in the mle nodemap |
838 | * but they might own this lockres. wait on them. */ |
839 | bit = find_next_bit(dlm->recovery_map, O2NM_MAX_NODES, 0); |
840 | if (bit < O2NM_MAX_NODES) { |
841 | mlog(ML_NOTICE, "%s:%.*s: at least one node (%d) to " |
842 | "recover before lock mastery can begin\n", |
843 | dlm->name, namelen, (char *)lockid, bit); |
844 | wait_on_recovery = 1; |
845 | } |
846 | } |
847 | |
848 | /* at this point there is either a DLM_MLE_BLOCK or a |
849 | * DLM_MLE_MASTER on the master list, so it's safe to add the |
850 | * lockres to the hashtable. anyone who finds the lock will |
851 | * still have to wait on the IN_PROGRESS. */ |
852 | |
853 | /* finally add the lockres to its hash bucket */ |
854 | __dlm_insert_lockres(dlm, res); |
855 | /* since this lockres is new it doesnt not require the spinlock */ |
856 | dlm_lockres_grab_inflight_ref_new(dlm, res); |
857 | |
858 | /* if this node does not become the master make sure to drop |
859 | * this inflight reference below */ |
860 | drop_inflight_if_nonlocal = 1; |
861 | |
862 | /* get an extra ref on the mle in case this is a BLOCK |
863 | * if so, the creator of the BLOCK may try to put the last |
864 | * ref at this time in the assert master handler, so we |
865 | * need an extra one to keep from a bad ptr deref. */ |
866 | dlm_get_mle_inuse(mle); |
867 | spin_unlock(&dlm->master_lock); |
868 | spin_unlock(&dlm->spinlock); |
869 | |
870 | redo_request: |
871 | while (wait_on_recovery) { |
872 | /* any cluster changes that occurred after dropping the |
873 | * dlm spinlock would be detectable be a change on the mle, |
874 | * so we only need to clear out the recovery map once. */ |
875 | if (dlm_is_recovery_lock(lockid, namelen)) { |
876 | mlog(ML_NOTICE, "%s: recovery map is not empty, but " |
877 | "must master $RECOVERY lock now\n", dlm->name); |
878 | if (!dlm_pre_master_reco_lockres(dlm, res)) |
879 | wait_on_recovery = 0; |
880 | else { |
881 | mlog(0, "%s: waiting 500ms for heartbeat state " |
882 | "change\n", dlm->name); |
883 | msleep(500); |
884 | } |
885 | continue; |
886 | } |
887 | |
888 | dlm_kick_recovery_thread(dlm); |
889 | msleep(1000); |
890 | dlm_wait_for_recovery(dlm); |
891 | |
892 | spin_lock(&dlm->spinlock); |
893 | bit = find_next_bit(dlm->recovery_map, O2NM_MAX_NODES, 0); |
894 | if (bit < O2NM_MAX_NODES) { |
895 | mlog(ML_NOTICE, "%s:%.*s: at least one node (%d) to " |
896 | "recover before lock mastery can begin\n", |
897 | dlm->name, namelen, (char *)lockid, bit); |
898 | wait_on_recovery = 1; |
899 | } else |
900 | wait_on_recovery = 0; |
901 | spin_unlock(&dlm->spinlock); |
902 | |
903 | if (wait_on_recovery) |
904 | dlm_wait_for_node_recovery(dlm, bit, 10000); |
905 | } |
906 | |
907 | /* must wait for lock to be mastered elsewhere */ |
908 | if (blocked) |
909 | goto wait; |
910 | |
911 | ret = -EINVAL; |
912 | dlm_node_iter_init(mle->vote_map, &iter); |
913 | while ((nodenum = dlm_node_iter_next(&iter)) >= 0) { |
914 | ret = dlm_do_master_request(res, mle, nodenum); |
915 | if (ret < 0) |
916 | mlog_errno(ret); |
917 | if (mle->master != O2NM_MAX_NODES) { |
918 | /* found a master ! */ |
919 | if (mle->master <= nodenum) |
920 | break; |
921 | /* if our master request has not reached the master |
922 | * yet, keep going until it does. this is how the |
923 | * master will know that asserts are needed back to |
924 | * the lower nodes. */ |
925 | mlog(0, "%s:%.*s: requests only up to %u but master " |
926 | "is %u, keep going\n", dlm->name, namelen, |
927 | lockid, nodenum, mle->master); |
928 | } |
929 | } |
930 | |
931 | wait: |
932 | /* keep going until the response map includes all nodes */ |
933 | ret = dlm_wait_for_lock_mastery(dlm, res, mle, &blocked); |
934 | if (ret < 0) { |
935 | wait_on_recovery = 1; |
936 | mlog(0, "%s:%.*s: node map changed, redo the " |
937 | "master request now, blocked=%d\n", |
938 | dlm->name, res->lockname.len, |
939 | res->lockname.name, blocked); |
940 | if (++tries > 20) { |
941 | mlog(ML_ERROR, "%s:%.*s: spinning on " |
942 | "dlm_wait_for_lock_mastery, blocked=%d\n", |
943 | dlm->name, res->lockname.len, |
944 | res->lockname.name, blocked); |
945 | dlm_print_one_lock_resource(res); |
946 | dlm_print_one_mle(mle); |
947 | tries = 0; |
948 | } |
949 | goto redo_request; |
950 | } |
951 | |
952 | mlog(0, "lockres mastered by %u\n", res->owner); |
953 | /* make sure we never continue without this */ |
954 | BUG_ON(res->owner == O2NM_MAX_NODES); |
955 | |
956 | /* master is known, detach if not already detached */ |
957 | dlm_mle_detach_hb_events(dlm, mle); |
958 | dlm_put_mle(mle); |
959 | /* put the extra ref */ |
960 | dlm_put_mle_inuse(mle); |
961 | |
962 | wake_waiters: |
963 | spin_lock(&res->spinlock); |
964 | if (res->owner != dlm->node_num && drop_inflight_if_nonlocal) |
965 | dlm_lockres_drop_inflight_ref(dlm, res); |
966 | res->state &= ~DLM_LOCK_RES_IN_PROGRESS; |
967 | spin_unlock(&res->spinlock); |
968 | wake_up(&res->wq); |
969 | |
970 | leave: |
971 | /* need to free the unused mle */ |
972 | if (alloc_mle) |
973 | kmem_cache_free(dlm_mle_cache, alloc_mle); |
974 | |
975 | return res; |
976 | } |
977 | |
978 | |
979 | #define DLM_MASTERY_TIMEOUT_MS 5000 |
980 | |
981 | static int dlm_wait_for_lock_mastery(struct dlm_ctxt *dlm, |
982 | struct dlm_lock_resource *res, |
983 | struct dlm_master_list_entry *mle, |
984 | int *blocked) |
985 | { |
986 | u8 m; |
987 | int ret, bit; |
988 | int map_changed, voting_done; |
989 | int assert, sleep; |
990 | |
991 | recheck: |
992 | ret = 0; |
993 | assert = 0; |
994 | |
995 | /* check if another node has already become the owner */ |
996 | spin_lock(&res->spinlock); |
997 | if (res->owner != DLM_LOCK_RES_OWNER_UNKNOWN) { |
998 | mlog(0, "%s:%.*s: owner is suddenly %u\n", dlm->name, |
999 | res->lockname.len, res->lockname.name, res->owner); |
1000 | spin_unlock(&res->spinlock); |
1001 | /* this will cause the master to re-assert across |
1002 | * the whole cluster, freeing up mles */ |
1003 | if (res->owner != dlm->node_num) { |
1004 | ret = dlm_do_master_request(res, mle, res->owner); |
1005 | if (ret < 0) { |
1006 | /* give recovery a chance to run */ |
1007 | mlog(ML_ERROR, "link to %u went down?: %d\n", res->owner, ret); |
1008 | msleep(500); |
1009 | goto recheck; |
1010 | } |
1011 | } |
1012 | ret = 0; |
1013 | goto leave; |
1014 | } |
1015 | spin_unlock(&res->spinlock); |
1016 | |
1017 | spin_lock(&mle->spinlock); |
1018 | m = mle->master; |
1019 | map_changed = (memcmp(mle->vote_map, mle->node_map, |
1020 | sizeof(mle->vote_map)) != 0); |
1021 | voting_done = (memcmp(mle->vote_map, mle->response_map, |
1022 | sizeof(mle->vote_map)) == 0); |
1023 | |
1024 | /* restart if we hit any errors */ |
1025 | if (map_changed) { |
1026 | int b; |
1027 | mlog(0, "%s: %.*s: node map changed, restarting\n", |
1028 | dlm->name, res->lockname.len, res->lockname.name); |
1029 | ret = dlm_restart_lock_mastery(dlm, res, mle, *blocked); |
1030 | b = (mle->type == DLM_MLE_BLOCK); |
1031 | if ((*blocked && !b) || (!*blocked && b)) { |
1032 | mlog(0, "%s:%.*s: status change: old=%d new=%d\n", |
1033 | dlm->name, res->lockname.len, res->lockname.name, |
1034 | *blocked, b); |
1035 | *blocked = b; |
1036 | } |
1037 | spin_unlock(&mle->spinlock); |
1038 | if (ret < 0) { |
1039 | mlog_errno(ret); |
1040 | goto leave; |
1041 | } |
1042 | mlog(0, "%s:%.*s: restart lock mastery succeeded, " |
1043 | "rechecking now\n", dlm->name, res->lockname.len, |
1044 | res->lockname.name); |
1045 | goto recheck; |
1046 | } else { |
1047 | if (!voting_done) { |
1048 | mlog(0, "map not changed and voting not done " |
1049 | "for %s:%.*s\n", dlm->name, res->lockname.len, |
1050 | res->lockname.name); |
1051 | } |
1052 | } |
1053 | |
1054 | if (m != O2NM_MAX_NODES) { |
1055 | /* another node has done an assert! |
1056 | * all done! */ |
1057 | sleep = 0; |
1058 | } else { |
1059 | sleep = 1; |
1060 | /* have all nodes responded? */ |
1061 | if (voting_done && !*blocked) { |
1062 | bit = find_next_bit(mle->maybe_map, O2NM_MAX_NODES, 0); |
1063 | if (dlm->node_num <= bit) { |
1064 | /* my node number is lowest. |
1065 | * now tell other nodes that I am |
1066 | * mastering this. */ |
1067 | mle->master = dlm->node_num; |
1068 | /* ref was grabbed in get_lock_resource |
1069 | * will be dropped in dlmlock_master */ |
1070 | assert = 1; |
1071 | sleep = 0; |
1072 | } |
1073 | /* if voting is done, but we have not received |
1074 | * an assert master yet, we must sleep */ |
1075 | } |
1076 | } |
1077 | |
1078 | spin_unlock(&mle->spinlock); |
1079 | |
1080 | /* sleep if we haven't finished voting yet */ |
1081 | if (sleep) { |
1082 | unsigned long timeo = msecs_to_jiffies(DLM_MASTERY_TIMEOUT_MS); |
1083 | |
1084 | /* |
1085 | if (atomic_read(&mle->mle_refs.refcount) < 2) |
1086 | mlog(ML_ERROR, "mle (%p) refs=%d, name=%.*s\n", mle, |
1087 | atomic_read(&mle->mle_refs.refcount), |
1088 | res->lockname.len, res->lockname.name); |
1089 | */ |
1090 | atomic_set(&mle->woken, 0); |
1091 | (void)wait_event_timeout(mle->wq, |
1092 | (atomic_read(&mle->woken) == 1), |
1093 | timeo); |
1094 | if (res->owner == O2NM_MAX_NODES) { |
1095 | mlog(0, "%s:%.*s: waiting again\n", dlm->name, |
1096 | res->lockname.len, res->lockname.name); |
1097 | goto recheck; |
1098 | } |
1099 | mlog(0, "done waiting, master is %u\n", res->owner); |
1100 | ret = 0; |
1101 | goto leave; |
1102 | } |
1103 | |
1104 | ret = 0; /* done */ |
1105 | if (assert) { |
1106 | m = dlm->node_num; |
1107 | mlog(0, "about to master %.*s here, this=%u\n", |
1108 | res->lockname.len, res->lockname.name, m); |
1109 | ret = dlm_do_assert_master(dlm, res, mle->vote_map, 0); |
1110 | if (ret) { |
1111 | /* This is a failure in the network path, |
1112 | * not in the response to the assert_master |
1113 | * (any nonzero response is a BUG on this node). |
1114 | * Most likely a socket just got disconnected |
1115 | * due to node death. */ |
1116 | mlog_errno(ret); |
1117 | } |
1118 | /* no longer need to restart lock mastery. |
1119 | * all living nodes have been contacted. */ |
1120 | ret = 0; |
1121 | } |
1122 | |
1123 | /* set the lockres owner */ |
1124 | spin_lock(&res->spinlock); |
1125 | /* mastery reference obtained either during |
1126 | * assert_master_handler or in get_lock_resource */ |
1127 | dlm_change_lockres_owner(dlm, res, m); |
1128 | spin_unlock(&res->spinlock); |
1129 | |
1130 | leave: |
1131 | return ret; |
1132 | } |
1133 | |
1134 | struct dlm_bitmap_diff_iter |
1135 | { |
1136 | int curnode; |
1137 | unsigned long *orig_bm; |
1138 | unsigned long *cur_bm; |
1139 | unsigned long diff_bm[BITS_TO_LONGS(O2NM_MAX_NODES)]; |
1140 | }; |
1141 | |
1142 | enum dlm_node_state_change |
1143 | { |
1144 | NODE_DOWN = -1, |
1145 | NODE_NO_CHANGE = 0, |
1146 | NODE_UP |
1147 | }; |
1148 | |
1149 | static void dlm_bitmap_diff_iter_init(struct dlm_bitmap_diff_iter *iter, |
1150 | unsigned long *orig_bm, |
1151 | unsigned long *cur_bm) |
1152 | { |
1153 | unsigned long p1, p2; |
1154 | int i; |
1155 | |
1156 | iter->curnode = -1; |
1157 | iter->orig_bm = orig_bm; |
1158 | iter->cur_bm = cur_bm; |
1159 | |
1160 | for (i = 0; i < BITS_TO_LONGS(O2NM_MAX_NODES); i++) { |
1161 | p1 = *(iter->orig_bm + i); |
1162 | p2 = *(iter->cur_bm + i); |
1163 | iter->diff_bm[i] = (p1 & ~p2) | (p2 & ~p1); |
1164 | } |
1165 | } |
1166 | |
1167 | static int dlm_bitmap_diff_iter_next(struct dlm_bitmap_diff_iter *iter, |
1168 | enum dlm_node_state_change *state) |
1169 | { |
1170 | int bit; |
1171 | |
1172 | if (iter->curnode >= O2NM_MAX_NODES) |
1173 | return -ENOENT; |
1174 | |
1175 | bit = find_next_bit(iter->diff_bm, O2NM_MAX_NODES, |
1176 | iter->curnode+1); |
1177 | if (bit >= O2NM_MAX_NODES) { |
1178 | iter->curnode = O2NM_MAX_NODES; |
1179 | return -ENOENT; |
1180 | } |
1181 | |
1182 | /* if it was there in the original then this node died */ |
1183 | if (test_bit(bit, iter->orig_bm)) |
1184 | *state = NODE_DOWN; |
1185 | else |
1186 | *state = NODE_UP; |
1187 | |
1188 | iter->curnode = bit; |
1189 | return bit; |
1190 | } |
1191 | |
1192 | |
1193 | static int dlm_restart_lock_mastery(struct dlm_ctxt *dlm, |
1194 | struct dlm_lock_resource *res, |
1195 | struct dlm_master_list_entry *mle, |
1196 | int blocked) |
1197 | { |
1198 | struct dlm_bitmap_diff_iter bdi; |
1199 | enum dlm_node_state_change sc; |
1200 | int node; |
1201 | int ret = 0; |
1202 | |
1203 | mlog(0, "something happened such that the " |
1204 | "master process may need to be restarted!\n"); |
1205 | |
1206 | assert_spin_locked(&mle->spinlock); |
1207 | |
1208 | dlm_bitmap_diff_iter_init(&bdi, mle->vote_map, mle->node_map); |
1209 | node = dlm_bitmap_diff_iter_next(&bdi, &sc); |
1210 | while (node >= 0) { |
1211 | if (sc == NODE_UP) { |
1212 | /* a node came up. clear any old vote from |
1213 | * the response map and set it in the vote map |
1214 | * then restart the mastery. */ |
1215 | mlog(ML_NOTICE, "node %d up while restarting\n", node); |
1216 | |
1217 | /* redo the master request, but only for the new node */ |
1218 | mlog(0, "sending request to new node\n"); |
1219 | clear_bit(node, mle->response_map); |
1220 | set_bit(node, mle->vote_map); |
1221 | } else { |
1222 | mlog(ML_ERROR, "node down! %d\n", node); |
1223 | if (blocked) { |
1224 | int lowest = find_next_bit(mle->maybe_map, |
1225 | O2NM_MAX_NODES, 0); |
1226 | |
1227 | /* act like it was never there */ |
1228 | clear_bit(node, mle->maybe_map); |
1229 | |
1230 | if (node == lowest) { |
1231 | mlog(0, "expected master %u died" |
1232 | " while this node was blocked " |
1233 | "waiting on it!\n", node); |
1234 | lowest = find_next_bit(mle->maybe_map, |
1235 | O2NM_MAX_NODES, |
1236 | lowest+1); |
1237 | if (lowest < O2NM_MAX_NODES) { |
1238 | mlog(0, "%s:%.*s:still " |
1239 | "blocked. waiting on %u " |
1240 | "now\n", dlm->name, |
1241 | res->lockname.len, |
1242 | res->lockname.name, |
1243 | lowest); |
1244 | } else { |
1245 | /* mle is an MLE_BLOCK, but |
1246 | * there is now nothing left to |
1247 | * block on. we need to return |
1248 | * all the way back out and try |
1249 | * again with an MLE_MASTER. |
1250 | * dlm_do_local_recovery_cleanup |
1251 | * has already run, so the mle |
1252 | * refcount is ok */ |
1253 | mlog(0, "%s:%.*s: no " |
1254 | "longer blocking. try to " |
1255 | "master this here\n", |
1256 | dlm->name, |
1257 | res->lockname.len, |
1258 | res->lockname.name); |
1259 | mle->type = DLM_MLE_MASTER; |
1260 | mle->mleres = res; |
1261 | } |
1262 | } |
1263 | } |
1264 | |
1265 | /* now blank out everything, as if we had never |
1266 | * contacted anyone */ |
1267 | memset(mle->maybe_map, 0, sizeof(mle->maybe_map)); |
1268 | memset(mle->response_map, 0, sizeof(mle->response_map)); |
1269 | /* reset the vote_map to the current node_map */ |
1270 | memcpy(mle->vote_map, mle->node_map, |
1271 | sizeof(mle->node_map)); |
1272 | /* put myself into the maybe map */ |
1273 | if (mle->type != DLM_MLE_BLOCK) |
1274 | set_bit(dlm->node_num, mle->maybe_map); |
1275 | } |
1276 | ret = -EAGAIN; |
1277 | node = dlm_bitmap_diff_iter_next(&bdi, &sc); |
1278 | } |
1279 | return ret; |
1280 | } |
1281 | |
1282 | |
1283 | /* |
1284 | * DLM_MASTER_REQUEST_MSG |
1285 | * |
1286 | * returns: 0 on success, |
1287 | * -errno on a network error |
1288 | * |
1289 | * on error, the caller should assume the target node is "dead" |
1290 | * |
1291 | */ |
1292 | |
1293 | static int dlm_do_master_request(struct dlm_lock_resource *res, |
1294 | struct dlm_master_list_entry *mle, int to) |
1295 | { |
1296 | struct dlm_ctxt *dlm = mle->dlm; |
1297 | struct dlm_master_request request; |
1298 | int ret, response=0, resend; |
1299 | |
1300 | memset(&request, 0, sizeof(request)); |
1301 | request.node_idx = dlm->node_num; |
1302 | |
1303 | BUG_ON(mle->type == DLM_MLE_MIGRATION); |
1304 | |
1305 | request.namelen = (u8)mle->mnamelen; |
1306 | memcpy(request.name, mle->mname, request.namelen); |
1307 | |
1308 | again: |
1309 | ret = o2net_send_message(DLM_MASTER_REQUEST_MSG, dlm->key, &request, |
1310 | sizeof(request), to, &response); |
1311 | if (ret < 0) { |
1312 | if (ret == -ESRCH) { |
1313 | /* should never happen */ |
1314 | mlog(ML_ERROR, "TCP stack not ready!\n"); |
1315 | BUG(); |
1316 | } else if (ret == -EINVAL) { |
1317 | mlog(ML_ERROR, "bad args passed to o2net!\n"); |
1318 | BUG(); |
1319 | } else if (ret == -ENOMEM) { |
1320 | mlog(ML_ERROR, "out of memory while trying to send " |
1321 | "network message! retrying\n"); |
1322 | /* this is totally crude */ |
1323 | msleep(50); |
1324 | goto again; |
1325 | } else if (!dlm_is_host_down(ret)) { |
1326 | /* not a network error. bad. */ |
1327 | mlog_errno(ret); |
1328 | mlog(ML_ERROR, "unhandled error!"); |
1329 | BUG(); |
1330 | } |
1331 | /* all other errors should be network errors, |
1332 | * and likely indicate node death */ |
1333 | mlog(ML_ERROR, "link to %d went down!\n", to); |
1334 | goto out; |
1335 | } |
1336 | |
1337 | ret = 0; |
1338 | resend = 0; |
1339 | spin_lock(&mle->spinlock); |
1340 | switch (response) { |
1341 | case DLM_MASTER_RESP_YES: |
1342 | set_bit(to, mle->response_map); |
1343 | mlog(0, "node %u is the master, response=YES\n", to); |
1344 | mlog(0, "%s:%.*s: master node %u now knows I have a " |
1345 | "reference\n", dlm->name, res->lockname.len, |
1346 | res->lockname.name, to); |
1347 | mle->master = to; |
1348 | break; |
1349 | case DLM_MASTER_RESP_NO: |
1350 | mlog(0, "node %u not master, response=NO\n", to); |
1351 | set_bit(to, mle->response_map); |
1352 | break; |
1353 | case DLM_MASTER_RESP_MAYBE: |
1354 | mlog(0, "node %u not master, response=MAYBE\n", to); |
1355 | set_bit(to, mle->response_map); |
1356 | set_bit(to, mle->maybe_map); |
1357 | break; |
1358 | case DLM_MASTER_RESP_ERROR: |
1359 | mlog(0, "node %u hit an error, resending\n", to); |
1360 | resend = 1; |
1361 | response = 0; |
1362 | break; |
1363 | default: |
1364 | mlog(ML_ERROR, "bad response! %u\n", response); |
1365 | BUG(); |
1366 | } |
1367 | spin_unlock(&mle->spinlock); |
1368 | if (resend) { |
1369 | /* this is also totally crude */ |
1370 | msleep(50); |
1371 | goto again; |
1372 | } |
1373 | |
1374 | out: |
1375 | return ret; |
1376 | } |
1377 | |
1378 | /* |
1379 | * locks that can be taken here: |
1380 | * dlm->spinlock |
1381 | * res->spinlock |
1382 | * mle->spinlock |
1383 | * dlm->master_list |
1384 | * |
1385 | * if possible, TRIM THIS DOWN!!! |
1386 | */ |
1387 | int dlm_master_request_handler(struct o2net_msg *msg, u32 len, void *data, |
1388 | void **ret_data) |
1389 | { |
1390 | u8 response = DLM_MASTER_RESP_MAYBE; |
1391 | struct dlm_ctxt *dlm = data; |
1392 | struct dlm_lock_resource *res = NULL; |
1393 | struct dlm_master_request *request = (struct dlm_master_request *) msg->buf; |
1394 | struct dlm_master_list_entry *mle = NULL, *tmpmle = NULL; |
1395 | char *name; |
1396 | unsigned int namelen, hash; |
1397 | int found, ret; |
1398 | int set_maybe; |
1399 | int dispatch_assert = 0; |
1400 | |
1401 | if (!dlm_grab(dlm)) |
1402 | return DLM_MASTER_RESP_NO; |
1403 | |
1404 | if (!dlm_domain_fully_joined(dlm)) { |
1405 | response = DLM_MASTER_RESP_NO; |
1406 | goto send_response; |
1407 | } |
1408 | |
1409 | name = request->name; |
1410 | namelen = request->namelen; |
1411 | hash = dlm_lockid_hash(name, namelen); |
1412 | |
1413 | if (namelen > DLM_LOCKID_NAME_MAX) { |
1414 | response = DLM_IVBUFLEN; |
1415 | goto send_response; |
1416 | } |
1417 | |
1418 | way_up_top: |
1419 | spin_lock(&dlm->spinlock); |
1420 | res = __dlm_lookup_lockres(dlm, name, namelen, hash); |
1421 | if (res) { |
1422 | spin_unlock(&dlm->spinlock); |
1423 | |
1424 | /* take care of the easy cases up front */ |
1425 | spin_lock(&res->spinlock); |
1426 | if (res->state & (DLM_LOCK_RES_RECOVERING| |
1427 | DLM_LOCK_RES_MIGRATING)) { |
1428 | spin_unlock(&res->spinlock); |
1429 | mlog(0, "returning DLM_MASTER_RESP_ERROR since res is " |
1430 | "being recovered/migrated\n"); |
1431 | response = DLM_MASTER_RESP_ERROR; |
1432 | if (mle) |
1433 | kmem_cache_free(dlm_mle_cache, mle); |
1434 | goto send_response; |
1435 | } |
1436 | |
1437 | if (res->owner == dlm->node_num) { |
1438 | mlog(0, "%s:%.*s: setting bit %u in refmap\n", |
1439 | dlm->name, namelen, name, request->node_idx); |
1440 | dlm_lockres_set_refmap_bit(request->node_idx, res); |
1441 | spin_unlock(&res->spinlock); |
1442 | response = DLM_MASTER_RESP_YES; |
1443 | if (mle) |
1444 | kmem_cache_free(dlm_mle_cache, mle); |
1445 | |
1446 | /* this node is the owner. |
1447 | * there is some extra work that needs to |
1448 | * happen now. the requesting node has |
1449 | * caused all nodes up to this one to |
1450 | * create mles. this node now needs to |
1451 | * go back and clean those up. */ |
1452 | dispatch_assert = 1; |
1453 | goto send_response; |
1454 | } else if (res->owner != DLM_LOCK_RES_OWNER_UNKNOWN) { |
1455 | spin_unlock(&res->spinlock); |
1456 | // mlog(0, "node %u is the master\n", res->owner); |
1457 | response = DLM_MASTER_RESP_NO; |
1458 | if (mle) |
1459 | kmem_cache_free(dlm_mle_cache, mle); |
1460 | goto send_response; |
1461 | } |
1462 | |
1463 | /* ok, there is no owner. either this node is |
1464 | * being blocked, or it is actively trying to |
1465 | * master this lock. */ |
1466 | if (!(res->state & DLM_LOCK_RES_IN_PROGRESS)) { |
1467 | mlog(ML_ERROR, "lock with no owner should be " |
1468 | "in-progress!\n"); |
1469 | BUG(); |
1470 | } |
1471 | |
1472 | // mlog(0, "lockres is in progress...\n"); |
1473 | spin_lock(&dlm->master_lock); |
1474 | found = dlm_find_mle(dlm, &tmpmle, name, namelen); |
1475 | if (!found) { |
1476 | mlog(ML_ERROR, "no mle found for this lock!\n"); |
1477 | BUG(); |
1478 | } |
1479 | set_maybe = 1; |
1480 | spin_lock(&tmpmle->spinlock); |
1481 | if (tmpmle->type == DLM_MLE_BLOCK) { |
1482 | // mlog(0, "this node is waiting for " |
1483 | // "lockres to be mastered\n"); |
1484 | response = DLM_MASTER_RESP_NO; |
1485 | } else if (tmpmle->type == DLM_MLE_MIGRATION) { |
1486 | mlog(0, "node %u is master, but trying to migrate to " |
1487 | "node %u.\n", tmpmle->master, tmpmle->new_master); |
1488 | if (tmpmle->master == dlm->node_num) { |
1489 | mlog(ML_ERROR, "no owner on lockres, but this " |
1490 | "node is trying to migrate it to %u?!\n", |
1491 | tmpmle->new_master); |
1492 | BUG(); |
1493 | } else { |
1494 | /* the real master can respond on its own */ |
1495 | response = DLM_MASTER_RESP_NO; |
1496 | } |
1497 | } else if (tmpmle->master != DLM_LOCK_RES_OWNER_UNKNOWN) { |
1498 | set_maybe = 0; |
1499 | if (tmpmle->master == dlm->node_num) { |
1500 | response = DLM_MASTER_RESP_YES; |
1501 | /* this node will be the owner. |
1502 | * go back and clean the mles on any |
1503 | * other nodes */ |
1504 | dispatch_assert = 1; |
1505 | dlm_lockres_set_refmap_bit(request->node_idx, res); |
1506 | mlog(0, "%s:%.*s: setting bit %u in refmap\n", |
1507 | dlm->name, namelen, name, |
1508 | request->node_idx); |
1509 | } else |
1510 | response = DLM_MASTER_RESP_NO; |
1511 | } else { |
1512 | // mlog(0, "this node is attempting to " |
1513 | // "master lockres\n"); |
1514 | response = DLM_MASTER_RESP_MAYBE; |
1515 | } |
1516 | if (set_maybe) |
1517 | set_bit(request->node_idx, tmpmle->maybe_map); |
1518 | spin_unlock(&tmpmle->spinlock); |
1519 | |
1520 | spin_unlock(&dlm->master_lock); |
1521 | spin_unlock(&res->spinlock); |
1522 | |
1523 | /* keep the mle attached to heartbeat events */ |
1524 | dlm_put_mle(tmpmle); |
1525 | if (mle) |
1526 | kmem_cache_free(dlm_mle_cache, mle); |
1527 | goto send_response; |
1528 | } |
1529 | |
1530 | /* |
1531 | * lockres doesn't exist on this node |
1532 | * if there is an MLE_BLOCK, return NO |
1533 | * if there is an MLE_MASTER, return MAYBE |
1534 | * otherwise, add an MLE_BLOCK, return NO |
1535 | */ |
1536 | spin_lock(&dlm->master_lock); |
1537 | found = dlm_find_mle(dlm, &tmpmle, name, namelen); |
1538 | if (!found) { |
1539 | /* this lockid has never been seen on this node yet */ |
1540 | // mlog(0, "no mle found\n"); |
1541 | if (!mle) { |
1542 | spin_unlock(&dlm->master_lock); |
1543 | spin_unlock(&dlm->spinlock); |
1544 | |
1545 | mle = (struct dlm_master_list_entry *) |
1546 | kmem_cache_alloc(dlm_mle_cache, GFP_NOFS); |
1547 | if (!mle) { |
1548 | response = DLM_MASTER_RESP_ERROR; |
1549 | mlog_errno(-ENOMEM); |
1550 | goto send_response; |
1551 | } |
1552 | goto way_up_top; |
1553 | } |
1554 | |
1555 | // mlog(0, "this is second time thru, already allocated, " |
1556 | // "add the block.\n"); |
1557 | dlm_init_mle(mle, DLM_MLE_BLOCK, dlm, NULL, name, namelen); |
1558 | set_bit(request->node_idx, mle->maybe_map); |
1559 | __dlm_insert_mle(dlm, mle); |
1560 | response = DLM_MASTER_RESP_NO; |
1561 | } else { |
1562 | // mlog(0, "mle was found\n"); |
1563 | set_maybe = 1; |
1564 | spin_lock(&tmpmle->spinlock); |
1565 | if (tmpmle->master == dlm->node_num) { |
1566 | mlog(ML_ERROR, "no lockres, but an mle with this node as master!\n"); |
1567 | BUG(); |
1568 | } |
1569 | if (tmpmle->type == DLM_MLE_BLOCK) |
1570 | response = DLM_MASTER_RESP_NO; |
1571 | else if (tmpmle->type == DLM_MLE_MIGRATION) { |
1572 | mlog(0, "migration mle was found (%u->%u)\n", |
1573 | tmpmle->master, tmpmle->new_master); |
1574 | /* real master can respond on its own */ |
1575 | response = DLM_MASTER_RESP_NO; |
1576 | } else |
1577 | response = DLM_MASTER_RESP_MAYBE; |
1578 | if (set_maybe) |
1579 | set_bit(request->node_idx, tmpmle->maybe_map); |
1580 | spin_unlock(&tmpmle->spinlock); |
1581 | } |
1582 | spin_unlock(&dlm->master_lock); |
1583 | spin_unlock(&dlm->spinlock); |
1584 | |
1585 | if (found) { |
1586 | /* keep the mle attached to heartbeat events */ |
1587 | dlm_put_mle(tmpmle); |
1588 | } |
1589 | send_response: |
1590 | /* |
1591 | * __dlm_lookup_lockres() grabbed a reference to this lockres. |
1592 | * The reference is released by dlm_assert_master_worker() under |
1593 | * the call to dlm_dispatch_assert_master(). If |
1594 | * dlm_assert_master_worker() isn't called, we drop it here. |
1595 | */ |
1596 | if (dispatch_assert) { |
1597 | if (response != DLM_MASTER_RESP_YES) |
1598 | mlog(ML_ERROR, "invalid response %d\n", response); |
1599 | if (!res) { |
1600 | mlog(ML_ERROR, "bad lockres while trying to assert!\n"); |
1601 | BUG(); |
1602 | } |
1603 | mlog(0, "%u is the owner of %.*s, cleaning everyone else\n", |
1604 | dlm->node_num, res->lockname.len, res->lockname.name); |
1605 | ret = dlm_dispatch_assert_master(dlm, res, 0, request->node_idx, |
1606 | DLM_ASSERT_MASTER_MLE_CLEANUP); |
1607 | if (ret < 0) { |
1608 | mlog(ML_ERROR, "failed to dispatch assert master work\n"); |
1609 | response = DLM_MASTER_RESP_ERROR; |
1610 | dlm_lockres_put(res); |
1611 | } |
1612 | } else { |
1613 | if (res) |
1614 | dlm_lockres_put(res); |
1615 | } |
1616 | |
1617 | dlm_put(dlm); |
1618 | return response; |
1619 | } |
1620 | |
1621 | /* |
1622 | * DLM_ASSERT_MASTER_MSG |
1623 | */ |
1624 | |
1625 | |
1626 | /* |
1627 | * NOTE: this can be used for debugging |
1628 | * can periodically run all locks owned by this node |
1629 | * and re-assert across the cluster... |
1630 | */ |
1631 | static int dlm_do_assert_master(struct dlm_ctxt *dlm, |
1632 | struct dlm_lock_resource *res, |
1633 | void *nodemap, u32 flags) |
1634 | { |
1635 | struct dlm_assert_master assert; |
1636 | int to, tmpret; |
1637 | struct dlm_node_iter iter; |
1638 | int ret = 0; |
1639 | int reassert; |
1640 | const char *lockname = res->lockname.name; |
1641 | unsigned int namelen = res->lockname.len; |
1642 | |
1643 | BUG_ON(namelen > O2NM_MAX_NAME_LEN); |
1644 | |
1645 | spin_lock(&res->spinlock); |
1646 | res->state |= DLM_LOCK_RES_SETREF_INPROG; |
1647 | spin_unlock(&res->spinlock); |
1648 | |
1649 | again: |
1650 | reassert = 0; |
1651 | |
1652 | /* note that if this nodemap is empty, it returns 0 */ |
1653 | dlm_node_iter_init(nodemap, &iter); |
1654 | while ((to = dlm_node_iter_next(&iter)) >= 0) { |
1655 | int r = 0; |
1656 | struct dlm_master_list_entry *mle = NULL; |
1657 | |
1658 | mlog(0, "sending assert master to %d (%.*s)\n", to, |
1659 | namelen, lockname); |
1660 | memset(&assert, 0, sizeof(assert)); |
1661 | assert.node_idx = dlm->node_num; |
1662 | assert.namelen = namelen; |
1663 | memcpy(assert.name, lockname, namelen); |
1664 | assert.flags = cpu_to_be32(flags); |
1665 | |
1666 | tmpret = o2net_send_message(DLM_ASSERT_MASTER_MSG, dlm->key, |
1667 | &assert, sizeof(assert), to, &r); |
1668 | if (tmpret < 0) { |
1669 | mlog(0, "assert_master returned %d!\n", tmpret); |
1670 | if (!dlm_is_host_down(tmpret)) { |
1671 | mlog(ML_ERROR, "unhandled error=%d!\n", tmpret); |
1672 | BUG(); |
1673 | } |
1674 | /* a node died. finish out the rest of the nodes. */ |
1675 | mlog(0, "link to %d went down!\n", to); |
1676 | /* any nonzero status return will do */ |
1677 | ret = tmpret; |
1678 | r = 0; |
1679 | } else if (r < 0) { |
1680 | /* ok, something horribly messed. kill thyself. */ |
1681 | mlog(ML_ERROR,"during assert master of %.*s to %u, " |
1682 | "got %d.\n", namelen, lockname, to, r); |
1683 | spin_lock(&dlm->spinlock); |
1684 | spin_lock(&dlm->master_lock); |
1685 | if (dlm_find_mle(dlm, &mle, (char *)lockname, |
1686 | namelen)) { |
1687 | dlm_print_one_mle(mle); |
1688 | __dlm_put_mle(mle); |
1689 | } |
1690 | spin_unlock(&dlm->master_lock); |
1691 | spin_unlock(&dlm->spinlock); |
1692 | BUG(); |
1693 | } |
1694 | |
1695 | if (r & DLM_ASSERT_RESPONSE_REASSERT && |
1696 | !(r & DLM_ASSERT_RESPONSE_MASTERY_REF)) { |
1697 | mlog(ML_ERROR, "%.*s: very strange, " |
1698 | "master MLE but no lockres on %u\n", |
1699 | namelen, lockname, to); |
1700 | } |
1701 | |
1702 | if (r & DLM_ASSERT_RESPONSE_REASSERT) { |
1703 | mlog(0, "%.*s: node %u create mles on other " |
1704 | "nodes and requests a re-assert\n", |
1705 | namelen, lockname, to); |
1706 | reassert = 1; |
1707 | } |
1708 | if (r & DLM_ASSERT_RESPONSE_MASTERY_REF) { |
1709 | mlog(0, "%.*s: node %u has a reference to this " |
1710 | "lockres, set the bit in the refmap\n", |
1711 | namelen, lockname, to); |
1712 | spin_lock(&res->spinlock); |
1713 | dlm_lockres_set_refmap_bit(to, res); |
1714 | spin_unlock(&res->spinlock); |
1715 | } |
1716 | } |
1717 | |
1718 | if (reassert) |
1719 | goto again; |
1720 | |
1721 | spin_lock(&res->spinlock); |
1722 | res->state &= ~DLM_LOCK_RES_SETREF_INPROG; |
1723 | spin_unlock(&res->spinlock); |
1724 | wake_up(&res->wq); |
1725 | |
1726 | return ret; |
1727 | } |
1728 | |
1729 | /* |
1730 | * locks that can be taken here: |
1731 | * dlm->spinlock |
1732 | * res->spinlock |
1733 | * mle->spinlock |
1734 | * dlm->master_list |
1735 | * |
1736 | * if possible, TRIM THIS DOWN!!! |
1737 | */ |
1738 | int dlm_assert_master_handler(struct o2net_msg *msg, u32 len, void *data, |
1739 | void **ret_data) |
1740 | { |
1741 | struct dlm_ctxt *dlm = data; |
1742 | struct dlm_master_list_entry *mle = NULL; |
1743 | struct dlm_assert_master *assert = (struct dlm_assert_master *)msg->buf; |
1744 | struct dlm_lock_resource *res = NULL; |
1745 | char *name; |
1746 | unsigned int namelen, hash; |
1747 | u32 flags; |
1748 | int master_request = 0, have_lockres_ref = 0; |
1749 | int ret = 0; |
1750 | |
1751 | if (!dlm_grab(dlm)) |
1752 | return 0; |
1753 | |
1754 | name = assert->name; |
1755 | namelen = assert->namelen; |
1756 | hash = dlm_lockid_hash(name, namelen); |
1757 | flags = be32_to_cpu(assert->flags); |
1758 | |
1759 | if (namelen > DLM_LOCKID_NAME_MAX) { |
1760 | mlog(ML_ERROR, "Invalid name length!"); |
1761 | goto done; |
1762 | } |
1763 | |
1764 | spin_lock(&dlm->spinlock); |
1765 | |
1766 | if (flags) |
1767 | mlog(0, "assert_master with flags: %u\n", flags); |
1768 | |
1769 | /* find the MLE */ |
1770 | spin_lock(&dlm->master_lock); |
1771 | if (!dlm_find_mle(dlm, &mle, name, namelen)) { |
1772 | /* not an error, could be master just re-asserting */ |
1773 | mlog(0, "just got an assert_master from %u, but no " |
1774 | "MLE for it! (%.*s)\n", assert->node_idx, |
1775 | namelen, name); |
1776 | } else { |
1777 | int bit = find_next_bit (mle->maybe_map, O2NM_MAX_NODES, 0); |
1778 | if (bit >= O2NM_MAX_NODES) { |
1779 | /* not necessarily an error, though less likely. |
1780 | * could be master just re-asserting. */ |
1781 | mlog(0, "no bits set in the maybe_map, but %u " |
1782 | "is asserting! (%.*s)\n", assert->node_idx, |
1783 | namelen, name); |
1784 | } else if (bit != assert->node_idx) { |
1785 | if (flags & DLM_ASSERT_MASTER_MLE_CLEANUP) { |
1786 | mlog(0, "master %u was found, %u should " |
1787 | "back off\n", assert->node_idx, bit); |
1788 | } else { |
1789 | /* with the fix for bug 569, a higher node |
1790 | * number winning the mastery will respond |
1791 | * YES to mastery requests, but this node |
1792 | * had no way of knowing. let it pass. */ |
1793 | mlog(0, "%u is the lowest node, " |
1794 | "%u is asserting. (%.*s) %u must " |
1795 | "have begun after %u won.\n", bit, |
1796 | assert->node_idx, namelen, name, bit, |
1797 | assert->node_idx); |
1798 | } |
1799 | } |
1800 | if (mle->type == DLM_MLE_MIGRATION) { |
1801 | if (flags & DLM_ASSERT_MASTER_MLE_CLEANUP) { |
1802 | mlog(0, "%s:%.*s: got cleanup assert" |
1803 | " from %u for migration\n", |
1804 | dlm->name, namelen, name, |
1805 | assert->node_idx); |
1806 | } else if (!(flags & DLM_ASSERT_MASTER_FINISH_MIGRATION)) { |
1807 | mlog(0, "%s:%.*s: got unrelated assert" |
1808 | " from %u for migration, ignoring\n", |
1809 | dlm->name, namelen, name, |
1810 | assert->node_idx); |
1811 | __dlm_put_mle(mle); |
1812 | spin_unlock(&dlm->master_lock); |
1813 | spin_unlock(&dlm->spinlock); |
1814 | goto done; |
1815 | } |
1816 | } |
1817 | } |
1818 | spin_unlock(&dlm->master_lock); |
1819 | |
1820 | /* ok everything checks out with the MLE |
1821 | * now check to see if there is a lockres */ |
1822 | res = __dlm_lookup_lockres(dlm, name, namelen, hash); |
1823 | if (res) { |
1824 | spin_lock(&res->spinlock); |
1825 | if (res->state & DLM_LOCK_RES_RECOVERING) { |
1826 | mlog(ML_ERROR, "%u asserting but %.*s is " |
1827 | "RECOVERING!\n", assert->node_idx, namelen, name); |
1828 | goto kill; |
1829 | } |
1830 | if (!mle) { |
1831 | if (res->owner != DLM_LOCK_RES_OWNER_UNKNOWN && |
1832 | res->owner != assert->node_idx) { |
1833 | mlog(ML_ERROR, "DIE! Mastery assert from %u, " |
1834 | "but current owner is %u! (%.*s)\n", |
1835 | assert->node_idx, res->owner, namelen, |
1836 | name); |
1837 | __dlm_print_one_lock_resource(res); |
1838 | BUG(); |
1839 | } |
1840 | } else if (mle->type != DLM_MLE_MIGRATION) { |
1841 | if (res->owner != DLM_LOCK_RES_OWNER_UNKNOWN) { |
1842 | /* owner is just re-asserting */ |
1843 | if (res->owner == assert->node_idx) { |
1844 | mlog(0, "owner %u re-asserting on " |
1845 | "lock %.*s\n", assert->node_idx, |
1846 | namelen, name); |
1847 | goto ok; |
1848 | } |
1849 | mlog(ML_ERROR, "got assert_master from " |
1850 | "node %u, but %u is the owner! " |
1851 | "(%.*s)\n", assert->node_idx, |
1852 | res->owner, namelen, name); |
1853 | goto kill; |
1854 | } |
1855 | if (!(res->state & DLM_LOCK_RES_IN_PROGRESS)) { |
1856 | mlog(ML_ERROR, "got assert from %u, but lock " |
1857 | "with no owner should be " |
1858 | "in-progress! (%.*s)\n", |
1859 | assert->node_idx, |
1860 | namelen, name); |
1861 | goto kill; |
1862 | } |
1863 | } else /* mle->type == DLM_MLE_MIGRATION */ { |
1864 | /* should only be getting an assert from new master */ |
1865 | if (assert->node_idx != mle->new_master) { |
1866 | mlog(ML_ERROR, "got assert from %u, but " |
1867 | "new master is %u, and old master " |
1868 | "was %u (%.*s)\n", |
1869 | assert->node_idx, mle->new_master, |
1870 | mle->master, namelen, name); |
1871 | goto kill; |
1872 | } |
1873 | |
1874 | } |
1875 | ok: |
1876 | spin_unlock(&res->spinlock); |
1877 | } |
1878 | |
1879 | // mlog(0, "woo! got an assert_master from node %u!\n", |
1880 | // assert->node_idx); |
1881 | if (mle) { |
1882 | int extra_ref = 0; |
1883 | int nn = -1; |
1884 | int rr, err = 0; |
1885 | |
1886 | spin_lock(&mle->spinlock); |
1887 | if (mle->type == DLM_MLE_BLOCK || mle->type == DLM_MLE_MIGRATION) |
1888 | extra_ref = 1; |
1889 | else { |
1890 | /* MASTER mle: if any bits set in the response map |
1891 | * then the calling node needs to re-assert to clear |
1892 | * up nodes that this node contacted */ |
1893 | while ((nn = find_next_bit (mle->response_map, O2NM_MAX_NODES, |
1894 | nn+1)) < O2NM_MAX_NODES) { |
1895 | if (nn != dlm->node_num && nn != assert->node_idx) |
1896 | master_request = 1; |
1897 | } |
1898 | } |
1899 | mle->master = assert->node_idx; |
1900 | atomic_set(&mle->woken, 1); |
1901 | wake_up(&mle->wq); |
1902 | spin_unlock(&mle->spinlock); |
1903 | |
1904 | if (res) { |
1905 | int wake = 0; |
1906 | spin_lock(&res->spinlock); |
1907 | if (mle->type == DLM_MLE_MIGRATION) { |
1908 | mlog(0, "finishing off migration of lockres %.*s, " |
1909 | "from %u to %u\n", |
1910 | res->lockname.len, res->lockname.name, |
1911 | dlm->node_num, mle->new_master); |
1912 | res->state &= ~DLM_LOCK_RES_MIGRATING; |
1913 | wake = 1; |
1914 | dlm_change_lockres_owner(dlm, res, mle->new_master); |
1915 | BUG_ON(res->state & DLM_LOCK_RES_DIRTY); |
1916 | } else { |
1917 | dlm_change_lockres_owner(dlm, res, mle->master); |
1918 | } |
1919 | spin_unlock(&res->spinlock); |
1920 | have_lockres_ref = 1; |
1921 | if (wake) |
1922 | wake_up(&res->wq); |
1923 | } |
1924 | |
1925 | /* master is known, detach if not already detached. |
1926 | * ensures that only one assert_master call will happen |
1927 | * on this mle. */ |
1928 | spin_lock(&dlm->master_lock); |
1929 | |
1930 | rr = atomic_read(&mle->mle_refs.refcount); |
1931 | if (mle->inuse > 0) { |
1932 | if (extra_ref && rr < 3) |
1933 | err = 1; |
1934 | else if (!extra_ref && rr < 2) |
1935 | err = 1; |
1936 | } else { |
1937 | if (extra_ref && rr < 2) |
1938 | err = 1; |
1939 | else if (!extra_ref && rr < 1) |
1940 | err = 1; |
1941 | } |
1942 | if (err) { |
1943 | mlog(ML_ERROR, "%s:%.*s: got assert master from %u " |
1944 | "that will mess up this node, refs=%d, extra=%d, " |
1945 | "inuse=%d\n", dlm->name, namelen, name, |
1946 | assert->node_idx, rr, extra_ref, mle->inuse); |
1947 | dlm_print_one_mle(mle); |
1948 | } |
1949 | __dlm_unlink_mle(dlm, mle); |
1950 | __dlm_mle_detach_hb_events(dlm, mle); |
1951 | __dlm_put_mle(mle); |
1952 | if (extra_ref) { |
1953 | /* the assert master message now balances the extra |
1954 | * ref given by the master / migration request message. |
1955 | * if this is the last put, it will be removed |
1956 | * from the list. */ |
1957 | __dlm_put_mle(mle); |
1958 | } |
1959 | spin_unlock(&dlm->master_lock); |
1960 | } else if (res) { |
1961 | if (res->owner != assert->node_idx) { |
1962 | mlog(0, "assert_master from %u, but current " |
1963 | "owner is %u (%.*s), no mle\n", assert->node_idx, |
1964 | res->owner, namelen, name); |
1965 | } |
1966 | } |
1967 | spin_unlock(&dlm->spinlock); |
1968 | |
1969 | done: |
1970 | ret = 0; |
1971 | if (res) { |
1972 | spin_lock(&res->spinlock); |
1973 | res->state |= DLM_LOCK_RES_SETREF_INPROG; |
1974 | spin_unlock(&res->spinlock); |
1975 | *ret_data = (void *)res; |
1976 | } |
1977 | dlm_put(dlm); |
1978 | if (master_request) { |
1979 | mlog(0, "need to tell master to reassert\n"); |
1980 | /* positive. negative would shoot down the node. */ |
1981 | ret |= DLM_ASSERT_RESPONSE_REASSERT; |
1982 | if (!have_lockres_ref) { |
1983 | mlog(ML_ERROR, "strange, got assert from %u, MASTER " |
1984 | "mle present here for %s:%.*s, but no lockres!\n", |
1985 | assert->node_idx, dlm->name, namelen, name); |
1986 | } |
1987 | } |
1988 | if (have_lockres_ref) { |
1989 | /* let the master know we have a reference to the lockres */ |
1990 | ret |= DLM_ASSERT_RESPONSE_MASTERY_REF; |
1991 | mlog(0, "%s:%.*s: got assert from %u, need a ref\n", |
1992 | dlm->name, namelen, name, assert->node_idx); |
1993 | } |
1994 | return ret; |
1995 | |
1996 | kill: |
1997 | /* kill the caller! */ |
1998 | mlog(ML_ERROR, "Bad message received from another node. Dumping state " |
1999 | "and killing the other node now! This node is OK and can continue.\n"); |
2000 | __dlm_print_one_lock_resource(res); |
2001 | spin_unlock(&res->spinlock); |
2002 | spin_unlock(&dlm->spinlock); |
2003 | *ret_data = (void *)res; |
2004 | dlm_put(dlm); |
2005 | return -EINVAL; |
2006 | } |
2007 | |
2008 | void dlm_assert_master_post_handler(int status, void *data, void *ret_data) |
2009 | { |
2010 | struct dlm_lock_resource *res = (struct dlm_lock_resource *)ret_data; |
2011 | |
2012 | if (ret_data) { |
2013 | spin_lock(&res->spinlock); |
2014 | res->state &= ~DLM_LOCK_RES_SETREF_INPROG; |
2015 | spin_unlock(&res->spinlock); |
2016 | wake_up(&res->wq); |
2017 | dlm_lockres_put(res); |
2018 | } |
2019 | return; |
2020 | } |
2021 | |
2022 | int dlm_dispatch_assert_master(struct dlm_ctxt *dlm, |
2023 | struct dlm_lock_resource *res, |
2024 | int ignore_higher, u8 request_from, u32 flags) |
2025 | { |
2026 | struct dlm_work_item *item; |
2027 | item = kzalloc(sizeof(*item), GFP_NOFS); |
2028 | if (!item) |
2029 | return -ENOMEM; |
2030 | |
2031 | |
2032 | /* queue up work for dlm_assert_master_worker */ |
2033 | dlm_grab(dlm); /* get an extra ref for the work item */ |
2034 | dlm_init_work_item(dlm, item, dlm_assert_master_worker, NULL); |
2035 | item->u.am.lockres = res; /* already have a ref */ |
2036 | /* can optionally ignore node numbers higher than this node */ |
2037 | item->u.am.ignore_higher = ignore_higher; |
2038 | item->u.am.request_from = request_from; |
2039 | item->u.am.flags = flags; |
2040 | |
2041 | if (ignore_higher) |
2042 | mlog(0, "IGNORE HIGHER: %.*s\n", res->lockname.len, |
2043 | res->lockname.name); |
2044 | |
2045 | spin_lock(&dlm->work_lock); |
2046 | list_add_tail(&item->list, &dlm->work_list); |
2047 | spin_unlock(&dlm->work_lock); |
2048 | |
2049 | queue_work(dlm->dlm_worker, &dlm->dispatched_work); |
2050 | return 0; |
2051 | } |
2052 | |
2053 | static void dlm_assert_master_worker(struct dlm_work_item *item, void *data) |
2054 | { |
2055 | struct dlm_ctxt *dlm = data; |
2056 | int ret = 0; |
2057 | struct dlm_lock_resource *res; |
2058 | unsigned long nodemap[BITS_TO_LONGS(O2NM_MAX_NODES)]; |
2059 | int ignore_higher; |
2060 | int bit; |
2061 | u8 request_from; |
2062 | u32 flags; |
2063 | |
2064 | dlm = item->dlm; |
2065 | res = item->u.am.lockres; |
2066 | ignore_higher = item->u.am.ignore_higher; |
2067 | request_from = item->u.am.request_from; |
2068 | flags = item->u.am.flags; |
2069 | |
2070 | spin_lock(&dlm->spinlock); |
2071 | memcpy(nodemap, dlm->domain_map, sizeof(nodemap)); |
2072 | spin_unlock(&dlm->spinlock); |
2073 | |
2074 | clear_bit(dlm->node_num, nodemap); |
2075 | if (ignore_higher) { |
2076 | /* if is this just to clear up mles for nodes below |
2077 | * this node, do not send the message to the original |
2078 | * caller or any node number higher than this */ |
2079 | clear_bit(request_from, nodemap); |
2080 | bit = dlm->node_num; |
2081 | while (1) { |
2082 | bit = find_next_bit(nodemap, O2NM_MAX_NODES, |
2083 | bit+1); |
2084 | if (bit >= O2NM_MAX_NODES) |
2085 | break; |
2086 | clear_bit(bit, nodemap); |
2087 | } |
2088 | } |
2089 | |
2090 | /* |
2091 | * If we're migrating this lock to someone else, we are no |
2092 | * longer allowed to assert out own mastery. OTOH, we need to |
2093 | * prevent migration from starting while we're still asserting |
2094 | * our dominance. The reserved ast delays migration. |
2095 | */ |
2096 | spin_lock(&res->spinlock); |
2097 | if (res->state & DLM_LOCK_RES_MIGRATING) { |
2098 | mlog(0, "Someone asked us to assert mastery, but we're " |
2099 | "in the middle of migration. Skipping assert, " |
2100 | "the new master will handle that.\n"); |
2101 | spin_unlock(&res->spinlock); |
2102 | goto put; |
2103 | } else |
2104 | __dlm_lockres_reserve_ast(res); |
2105 | spin_unlock(&res->spinlock); |
2106 | |
2107 | /* this call now finishes out the nodemap |
2108 | * even if one or more nodes die */ |
2109 | mlog(0, "worker about to master %.*s here, this=%u\n", |
2110 | res->lockname.len, res->lockname.name, dlm->node_num); |
2111 | ret = dlm_do_assert_master(dlm, res, nodemap, flags); |
2112 | if (ret < 0) { |
2113 | /* no need to restart, we are done */ |
2114 | if (!dlm_is_host_down(ret)) |
2115 | mlog_errno(ret); |
2116 | } |
2117 | |
2118 | /* Ok, we've asserted ourselves. Let's let migration start. */ |
2119 | dlm_lockres_release_ast(dlm, res); |
2120 | |
2121 | put: |
2122 | dlm_lockres_put(res); |
2123 | |
2124 | mlog(0, "finished with dlm_assert_master_worker\n"); |
2125 | } |
2126 | |
2127 | /* SPECIAL CASE for the $RECOVERY lock used by the recovery thread. |
2128 | * We cannot wait for node recovery to complete to begin mastering this |
2129 | * lockres because this lockres is used to kick off recovery! ;-) |
2130 | * So, do a pre-check on all living nodes to see if any of those nodes |
2131 | * think that $RECOVERY is currently mastered by a dead node. If so, |
2132 | * we wait a short time to allow that node to get notified by its own |
2133 | * heartbeat stack, then check again. All $RECOVERY lock resources |
2134 | * mastered by dead nodes are purged when the hearbeat callback is |
2135 | * fired, so we can know for sure that it is safe to continue once |
2136 | * the node returns a live node or no node. */ |
2137 | static int dlm_pre_master_reco_lockres(struct dlm_ctxt *dlm, |
2138 | struct dlm_lock_resource *res) |
2139 | { |
2140 | struct dlm_node_iter iter; |
2141 | int nodenum; |
2142 | int ret = 0; |
2143 | u8 master = DLM_LOCK_RES_OWNER_UNKNOWN; |
2144 | |
2145 | spin_lock(&dlm->spinlock); |
2146 | dlm_node_iter_init(dlm->domain_map, &iter); |
2147 | spin_unlock(&dlm->spinlock); |
2148 | |
2149 | while ((nodenum = dlm_node_iter_next(&iter)) >= 0) { |
2150 | /* do not send to self */ |
2151 | if (nodenum == dlm->node_num) |
2152 | continue; |
2153 | ret = dlm_do_master_requery(dlm, res, nodenum, &master); |
2154 | if (ret < 0) { |
2155 | mlog_errno(ret); |
2156 | if (!dlm_is_host_down(ret)) |
2157 | BUG(); |
2158 | /* host is down, so answer for that node would be |
2159 | * DLM_LOCK_RES_OWNER_UNKNOWN. continue. */ |
2160 | ret = 0; |
2161 | } |
2162 | |
2163 | if (master != DLM_LOCK_RES_OWNER_UNKNOWN) { |
2164 | /* check to see if this master is in the recovery map */ |
2165 | spin_lock(&dlm->spinlock); |
2166 | if (test_bit(master, dlm->recovery_map)) { |
2167 | mlog(ML_NOTICE, "%s: node %u has not seen " |
2168 | "node %u go down yet, and thinks the " |
2169 | "dead node is mastering the recovery " |
2170 | "lock. must wait.\n", dlm->name, |
2171 | nodenum, master); |
2172 | ret = -EAGAIN; |
2173 | } |
2174 | spin_unlock(&dlm->spinlock); |
2175 | mlog(0, "%s: reco lock master is %u\n", dlm->name, |
2176 | master); |
2177 | break; |
2178 | } |
2179 | } |
2180 | return ret; |
2181 | } |
2182 | |
2183 | /* |
2184 | * DLM_DEREF_LOCKRES_MSG |
2185 | */ |
2186 | |
2187 | int dlm_drop_lockres_ref(struct dlm_ctxt *dlm, struct dlm_lock_resource *res) |
2188 | { |
2189 | struct dlm_deref_lockres deref; |
2190 | int ret = 0, r; |
2191 | const char *lockname; |
2192 | unsigned int namelen; |
2193 | |
2194 | lockname = res->lockname.name; |
2195 | namelen = res->lockname.len; |
2196 | BUG_ON(namelen > O2NM_MAX_NAME_LEN); |
2197 | |
2198 | mlog(0, "%s:%.*s: sending deref to %d\n", |
2199 | dlm->name, namelen, lockname, res->owner); |
2200 | memset(&deref, 0, sizeof(deref)); |
2201 | deref.node_idx = dlm->node_num; |
2202 | deref.namelen = namelen; |
2203 | memcpy(deref.name, lockname, namelen); |
2204 | |
2205 | ret = o2net_send_message(DLM_DEREF_LOCKRES_MSG, dlm->key, |
2206 | &deref, sizeof(deref), res->owner, &r); |
2207 | if (ret < 0) |
2208 | mlog_errno(ret); |
2209 | else if (r < 0) { |
2210 | /* BAD. other node says I did not have a ref. */ |
2211 | mlog(ML_ERROR,"while dropping ref on %s:%.*s " |
2212 | "(master=%u) got %d.\n", dlm->name, namelen, |
2213 | lockname, res->owner, r); |
2214 | dlm_print_one_lock_resource(res); |
2215 | BUG(); |
2216 | } |
2217 | return ret; |
2218 | } |
2219 | |
2220 | int dlm_deref_lockres_handler(struct o2net_msg *msg, u32 len, void *data, |
2221 | void **ret_data) |
2222 | { |
2223 | struct dlm_ctxt *dlm = data; |
2224 | struct dlm_deref_lockres *deref = (struct dlm_deref_lockres *)msg->buf; |
2225 | struct dlm_lock_resource *res = NULL; |
2226 | char *name; |
2227 | unsigned int namelen; |
2228 | int ret = -EINVAL; |
2229 | u8 node; |
2230 | unsigned int hash; |
2231 | struct dlm_work_item *item; |
2232 | int cleared = 0; |
2233 | int dispatch = 0; |
2234 | |
2235 | if (!dlm_grab(dlm)) |
2236 | return 0; |
2237 | |
2238 | name = deref->name; |
2239 | namelen = deref->namelen; |
2240 | node = deref->node_idx; |
2241 | |
2242 | if (namelen > DLM_LOCKID_NAME_MAX) { |
2243 | mlog(ML_ERROR, "Invalid name length!"); |
2244 | goto done; |
2245 | } |
2246 | if (deref->node_idx >= O2NM_MAX_NODES) { |
2247 | mlog(ML_ERROR, "Invalid node number: %u\n", node); |
2248 | goto done; |
2249 | } |
2250 | |
2251 | hash = dlm_lockid_hash(name, namelen); |
2252 | |
2253 | spin_lock(&dlm->spinlock); |
2254 | res = __dlm_lookup_lockres_full(dlm, name, namelen, hash); |
2255 | if (!res) { |
2256 | spin_unlock(&dlm->spinlock); |
2257 | mlog(ML_ERROR, "%s:%.*s: bad lockres name\n", |
2258 | dlm->name, namelen, name); |
2259 | goto done; |
2260 | } |
2261 | spin_unlock(&dlm->spinlock); |
2262 | |
2263 | spin_lock(&res->spinlock); |
2264 | if (res->state & DLM_LOCK_RES_SETREF_INPROG) |
2265 | dispatch = 1; |
2266 | else { |
2267 | BUG_ON(res->state & DLM_LOCK_RES_DROPPING_REF); |
2268 | if (test_bit(node, res->refmap)) { |
2269 | dlm_lockres_clear_refmap_bit(node, res); |
2270 | cleared = 1; |
2271 | } |
2272 | } |
2273 | spin_unlock(&res->spinlock); |
2274 | |
2275 | if (!dispatch) { |
2276 | if (cleared) |
2277 | dlm_lockres_calc_usage(dlm, res); |
2278 | else { |
2279 | mlog(ML_ERROR, "%s:%.*s: node %u trying to drop ref " |
2280 | "but it is already dropped!\n", dlm->name, |
2281 | res->lockname.len, res->lockname.name, node); |
2282 | dlm_print_one_lock_resource(res); |
2283 | } |
2284 | ret = 0; |
2285 | goto done; |
2286 | } |
2287 | |
2288 | item = kzalloc(sizeof(*item), GFP_NOFS); |
2289 | if (!item) { |
2290 | ret = -ENOMEM; |
2291 | mlog_errno(ret); |
2292 | goto done; |
2293 | } |
2294 | |
2295 | dlm_init_work_item(dlm, item, dlm_deref_lockres_worker, NULL); |
2296 | item->u.dl.deref_res = res; |
2297 | item->u.dl.deref_node = node; |
2298 | |
2299 | spin_lock(&dlm->work_lock); |
2300 | list_add_tail(&item->list, &dlm->work_list); |
2301 | spin_unlock(&dlm->work_lock); |
2302 | |
2303 | queue_work(dlm->dlm_worker, &dlm->dispatched_work); |
2304 | return 0; |
2305 | |
2306 | done: |
2307 | if (res) |
2308 | dlm_lockres_put(res); |
2309 | dlm_put(dlm); |
2310 | |
2311 | return ret; |
2312 | } |
2313 | |
2314 | static void dlm_deref_lockres_worker(struct dlm_work_item *item, void *data) |
2315 | { |
2316 | struct dlm_ctxt *dlm; |
2317 | struct dlm_lock_resource *res; |
2318 | u8 node; |
2319 | u8 cleared = 0; |
2320 | |
2321 | dlm = item->dlm; |
2322 | res = item->u.dl.deref_res; |
2323 | node = item->u.dl.deref_node; |
2324 | |
2325 | spin_lock(&res->spinlock); |
2326 | BUG_ON(res->state & DLM_LOCK_RES_DROPPING_REF); |
2327 | if (test_bit(node, res->refmap)) { |
2328 | __dlm_wait_on_lockres_flags(res, DLM_LOCK_RES_SETREF_INPROG); |
2329 | dlm_lockres_clear_refmap_bit(node, res); |
2330 | cleared = 1; |
2331 | } |
2332 | spin_unlock(&res->spinlock); |
2333 | |
2334 | if (cleared) { |
2335 | mlog(0, "%s:%.*s node %u ref dropped in dispatch\n", |
2336 | dlm->name, res->lockname.len, res->lockname.name, node); |
2337 | dlm_lockres_calc_usage(dlm, res); |
2338 | } else { |
2339 | mlog(ML_ERROR, "%s:%.*s: node %u trying to drop ref " |
2340 | "but it is already dropped!\n", dlm->name, |
2341 | res->lockname.len, res->lockname.name, node); |
2342 | dlm_print_one_lock_resource(res); |
2343 | } |
2344 | |
2345 | dlm_lockres_put(res); |
2346 | } |
2347 | |
2348 | /* Checks whether the lockres can be migrated. Returns 0 if yes, < 0 |
2349 | * if not. If 0, numlocks is set to the number of locks in the lockres. |
2350 | */ |
2351 | static int dlm_is_lockres_migrateable(struct dlm_ctxt *dlm, |
2352 | struct dlm_lock_resource *res, |
2353 | int *numlocks) |
2354 | { |
2355 | int ret; |
2356 | int i; |
2357 | int count = 0; |
2358 | struct list_head *queue; |
2359 | struct dlm_lock *lock; |
2360 | |
2361 | assert_spin_locked(&res->spinlock); |
2362 | |
2363 | ret = -EINVAL; |
2364 | if (res->owner == DLM_LOCK_RES_OWNER_UNKNOWN) { |
2365 | mlog(0, "cannot migrate lockres with unknown owner!\n"); |
2366 | goto leave; |
2367 | } |
2368 | |
2369 | if (res->owner != dlm->node_num) { |
2370 | mlog(0, "cannot migrate lockres this node doesn't own!\n"); |
2371 | goto leave; |
2372 | } |
2373 | |
2374 | ret = 0; |
2375 | queue = &res->granted; |
2376 | for (i = 0; i < 3; i++) { |
2377 | list_for_each_entry(lock, queue, list) { |
2378 | ++count; |
2379 | if (lock->ml.node == dlm->node_num) { |
2380 | mlog(0, "found a lock owned by this node still " |
2381 | "on the %s queue! will not migrate this " |
2382 | "lockres\n", (i == 0 ? "granted" : |
2383 | (i == 1 ? "converting" : |
2384 | "blocked"))); |
2385 | ret = -ENOTEMPTY; |
2386 | goto leave; |
2387 | } |
2388 | } |
2389 | queue++; |
2390 | } |
2391 | |
2392 | *numlocks = count; |
2393 | mlog(0, "migrateable lockres having %d locks\n", *numlocks); |
2394 | |
2395 | leave: |
2396 | return ret; |
2397 | } |
2398 | |
2399 | /* |
2400 | * DLM_MIGRATE_LOCKRES |
2401 | */ |
2402 | |
2403 | |
2404 | static int dlm_migrate_lockres(struct dlm_ctxt *dlm, |
2405 | struct dlm_lock_resource *res, |
2406 | u8 target) |
2407 | { |
2408 | struct dlm_master_list_entry *mle = NULL; |
2409 | struct dlm_master_list_entry *oldmle = NULL; |
2410 | struct dlm_migratable_lockres *mres = NULL; |
2411 | int ret = 0; |
2412 | const char *name; |
2413 | unsigned int namelen; |
2414 | int mle_added = 0; |
2415 | int numlocks; |
2416 | int wake = 0; |
2417 | |
2418 | if (!dlm_grab(dlm)) |
2419 | return -EINVAL; |
2420 | |
2421 | name = res->lockname.name; |
2422 | namelen = res->lockname.len; |
2423 | |
2424 | mlog(0, "migrating %.*s to %u\n", namelen, name, target); |
2425 | |
2426 | /* |
2427 | * ensure this lockres is a proper candidate for migration |
2428 | */ |
2429 | spin_lock(&res->spinlock); |
2430 | ret = dlm_is_lockres_migrateable(dlm, res, &numlocks); |
2431 | if (ret < 0) { |
2432 | spin_unlock(&res->spinlock); |
2433 | goto leave; |
2434 | } |
2435 | spin_unlock(&res->spinlock); |
2436 | |
2437 | /* no work to do */ |
2438 | if (numlocks == 0) { |
2439 | mlog(0, "no locks were found on this lockres! done!\n"); |
2440 | goto leave; |
2441 | } |
2442 | |
2443 | /* |
2444 | * preallocate up front |
2445 | * if this fails, abort |
2446 | */ |
2447 | |
2448 | ret = -ENOMEM; |
2449 | mres = (struct dlm_migratable_lockres *) __get_free_page(GFP_NOFS); |
2450 | if (!mres) { |
2451 | mlog_errno(ret); |
2452 | goto leave; |
2453 | } |
2454 | |
2455 | mle = (struct dlm_master_list_entry *) kmem_cache_alloc(dlm_mle_cache, |
2456 | GFP_NOFS); |
2457 | if (!mle) { |
2458 | mlog_errno(ret); |
2459 | goto leave; |
2460 | } |
2461 | ret = 0; |
2462 | |
2463 | /* |
2464 | * find a node to migrate the lockres to |
2465 | */ |
2466 | |
2467 | mlog(0, "picking a migration node\n"); |
2468 | spin_lock(&dlm->spinlock); |
2469 | /* pick a new node */ |
2470 | if (!test_bit(target, dlm->domain_map) || |
2471 | target >= O2NM_MAX_NODES) { |
2472 | target = dlm_pick_migration_target(dlm, res); |
2473 | } |
2474 | mlog(0, "node %u chosen for migration\n", target); |
2475 | |
2476 | if (target >= O2NM_MAX_NODES || |
2477 | !test_bit(target, dlm->domain_map)) { |
2478 | /* target chosen is not alive */ |
2479 | ret = -EINVAL; |
2480 | } |
2481 | |
2482 | if (ret) { |
2483 | spin_unlock(&dlm->spinlock); |
2484 | goto fail; |
2485 | } |
2486 | |
2487 | mlog(0, "continuing with target = %u\n", target); |
2488 | |
2489 | /* |
2490 | * clear any existing master requests and |
2491 | * add the migration mle to the list |
2492 | */ |
2493 | spin_lock(&dlm->master_lock); |
2494 | ret = dlm_add_migration_mle(dlm, res, mle, &oldmle, name, |
2495 | namelen, target, dlm->node_num); |
2496 | spin_unlock(&dlm->master_lock); |
2497 | spin_unlock(&dlm->spinlock); |
2498 | |
2499 | if (ret == -EEXIST) { |
2500 | mlog(0, "another process is already migrating it\n"); |
2501 | goto fail; |
2502 | } |
2503 | mle_added = 1; |
2504 | |
2505 | /* |
2506 | * set the MIGRATING flag and flush asts |
2507 | * if we fail after this we need to re-dirty the lockres |
2508 | */ |
2509 | if (dlm_mark_lockres_migrating(dlm, res, target) < 0) { |
2510 | mlog(ML_ERROR, "tried to migrate %.*s to %u, but " |
2511 | "the target went down.\n", res->lockname.len, |
2512 | res->lockname.name, target); |
2513 | spin_lock(&res->spinlock); |
2514 | res->state &= ~DLM_LOCK_RES_MIGRATING; |
2515 | wake = 1; |
2516 | spin_unlock(&res->spinlock); |
2517 | ret = -EINVAL; |
2518 | } |
2519 | |
2520 | fail: |
2521 | if (oldmle) { |
2522 | /* master is known, detach if not already detached */ |
2523 | dlm_mle_detach_hb_events(dlm, oldmle); |
2524 | dlm_put_mle(oldmle); |
2525 | } |
2526 | |
2527 | if (ret < 0) { |
2528 | if (mle_added) { |
2529 | dlm_mle_detach_hb_events(dlm, mle); |
2530 | dlm_put_mle(mle); |
2531 | } else if (mle) { |
2532 | kmem_cache_free(dlm_mle_cache, mle); |
2533 | } |
2534 | goto leave; |
2535 | } |
2536 | |
2537 | /* |
2538 | * at this point, we have a migration target, an mle |
2539 | * in the master list, and the MIGRATING flag set on |
2540 | * the lockres |
2541 | */ |
2542 | |
2543 | /* now that remote nodes are spinning on the MIGRATING flag, |
2544 | * ensure that all assert_master work is flushed. */ |
2545 | flush_workqueue(dlm->dlm_worker); |
2546 | |
2547 | /* get an extra reference on the mle. |
2548 | * otherwise the assert_master from the new |
2549 | * master will destroy this. |
2550 | * also, make sure that all callers of dlm_get_mle |
2551 | * take both dlm->spinlock and dlm->master_lock */ |
2552 | spin_lock(&dlm->spinlock); |
2553 | spin_lock(&dlm->master_lock); |
2554 | dlm_get_mle_inuse(mle); |
2555 | spin_unlock(&dlm->master_lock); |
2556 | spin_unlock(&dlm->spinlock); |
2557 | |
2558 | /* notify new node and send all lock state */ |
2559 | /* call send_one_lockres with migration flag. |
2560 | * this serves as notice to the target node that a |
2561 | * migration is starting. */ |
2562 | ret = dlm_send_one_lockres(dlm, res, mres, target, |
2563 | DLM_MRES_MIGRATION); |
2564 | |
2565 | if (ret < 0) { |
2566 | mlog(0, "migration to node %u failed with %d\n", |
2567 | target, ret); |
2568 | /* migration failed, detach and clean up mle */ |
2569 | dlm_mle_detach_hb_events(dlm, mle); |
2570 | dlm_put_mle(mle); |
2571 | dlm_put_mle_inuse(mle); |
2572 | spin_lock(&res->spinlock); |
2573 | res->state &= ~DLM_LOCK_RES_MIGRATING; |
2574 | wake = 1; |
2575 | spin_unlock(&res->spinlock); |
2576 | goto leave; |
2577 | } |
2578 | |
2579 | /* at this point, the target sends a message to all nodes, |
2580 | * (using dlm_do_migrate_request). this node is skipped since |
2581 | * we had to put an mle in the list to begin the process. this |
2582 | * node now waits for target to do an assert master. this node |
2583 | * will be the last one notified, ensuring that the migration |
2584 | * is complete everywhere. if the target dies while this is |
2585 | * going on, some nodes could potentially see the target as the |
2586 | * master, so it is important that my recovery finds the migration |
2587 | * mle and sets the master to UNKNOWN. */ |
2588 | |
2589 | |
2590 | /* wait for new node to assert master */ |
2591 | while (1) { |
2592 | ret = wait_event_interruptible_timeout(mle->wq, |
2593 | (atomic_read(&mle->woken) == 1), |
2594 | msecs_to_jiffies(5000)); |
2595 | |
2596 | if (ret >= 0) { |
2597 | if (atomic_read(&mle->woken) == 1 || |
2598 | res->owner == target) |
2599 | break; |
2600 | |
2601 | mlog(0, "%s:%.*s: timed out during migration\n", |
2602 | dlm->name, res->lockname.len, res->lockname.name); |
2603 | /* avoid hang during shutdown when migrating lockres |
2604 | * to a node which also goes down */ |
2605 | if (dlm_is_node_dead(dlm, target)) { |
2606 | mlog(0, "%s:%.*s: expected migration " |
2607 | "target %u is no longer up, restarting\n", |
2608 | dlm->name, res->lockname.len, |
2609 | res->lockname.name, target); |
2610 | ret = -EINVAL; |
2611 | /* migration failed, detach and clean up mle */ |
2612 | dlm_mle_detach_hb_events(dlm, mle); |
2613 | dlm_put_mle(mle); |
2614 | dlm_put_mle_inuse(mle); |
2615 | spin_lock(&res->spinlock); |
2616 | res->state &= ~DLM_LOCK_RES_MIGRATING; |
2617 | wake = 1; |
2618 | spin_unlock(&res->spinlock); |
2619 | goto leave; |
2620 | } |
2621 | } else |
2622 | mlog(0, "%s:%.*s: caught signal during migration\n", |
2623 | dlm->name, res->lockname.len, res->lockname.name); |
2624 | } |
2625 | |
2626 | /* all done, set the owner, clear the flag */ |
2627 | spin_lock(&res->spinlock); |
2628 | dlm_set_lockres_owner(dlm, res, target); |
2629 | res->state &= ~DLM_LOCK_RES_MIGRATING; |
2630 | dlm_remove_nonlocal_locks(dlm, res); |
2631 | spin_unlock(&res->spinlock); |
2632 | wake_up(&res->wq); |
2633 | |
2634 | /* master is known, detach if not already detached */ |
2635 | dlm_mle_detach_hb_events(dlm, mle); |
2636 | dlm_put_mle_inuse(mle); |
2637 | ret = 0; |
2638 | |
2639 | dlm_lockres_calc_usage(dlm, res); |
2640 | |
2641 | leave: |
2642 | /* re-dirty the lockres if we failed */ |
2643 | if (ret < 0) |
2644 | dlm_kick_thread(dlm, res); |
2645 | |
2646 | /* wake up waiters if the MIGRATING flag got set |
2647 | * but migration failed */ |
2648 | if (wake) |
2649 | wake_up(&res->wq); |
2650 | |
2651 | /* TODO: cleanup */ |
2652 | if (mres) |
2653 | free_page((unsigned long)mres); |
2654 | |
2655 | dlm_put(dlm); |
2656 | |
2657 | mlog(0, "returning %d\n", ret); |
2658 | return ret; |
2659 | } |
2660 | |
2661 | #define DLM_MIGRATION_RETRY_MS 100 |
2662 | |
2663 | /* Should be called only after beginning the domain leave process. |
2664 | * There should not be any remaining locks on nonlocal lock resources, |
2665 | * and there should be no local locks left on locally mastered resources. |
2666 | * |
2667 | * Called with the dlm spinlock held, may drop it to do migration, but |
2668 | * will re-acquire before exit. |
2669 | * |
2670 | * Returns: 1 if dlm->spinlock was dropped/retaken, 0 if never dropped */ |
2671 | int dlm_empty_lockres(struct dlm_ctxt *dlm, struct dlm_lock_resource *res) |
2672 | { |
2673 | int ret; |
2674 | int lock_dropped = 0; |
2675 | int numlocks; |
2676 | |
2677 | spin_lock(&res->spinlock); |
2678 | if (res->owner != dlm->node_num) { |
2679 | if (!__dlm_lockres_unused(res)) { |
2680 | mlog(ML_ERROR, "%s:%.*s: this node is not master, " |
2681 | "trying to free this but locks remain\n", |
2682 | dlm->name, res->lockname.len, res->lockname.name); |
2683 | } |
2684 | spin_unlock(&res->spinlock); |
2685 | goto leave; |
2686 | } |
2687 | |
2688 | /* No need to migrate a lockres having no locks */ |
2689 | ret = dlm_is_lockres_migrateable(dlm, res, &numlocks); |
2690 | if (ret >= 0 && numlocks == 0) { |
2691 | spin_unlock(&res->spinlock); |
2692 | goto leave; |
2693 | } |
2694 | spin_unlock(&res->spinlock); |
2695 | |
2696 | /* Wheee! Migrate lockres here! Will sleep so drop spinlock. */ |
2697 | spin_unlock(&dlm->spinlock); |
2698 | lock_dropped = 1; |
2699 | while (1) { |
2700 | ret = dlm_migrate_lockres(dlm, res, O2NM_MAX_NODES); |
2701 | if (ret >= 0) |
2702 | break; |
2703 | if (ret == -ENOTEMPTY) { |
2704 | mlog(ML_ERROR, "lockres %.*s still has local locks!\n", |
2705 | res->lockname.len, res->lockname.name); |
2706 | BUG(); |
2707 | } |
2708 | |
2709 | mlog(0, "lockres %.*s: migrate failed, " |
2710 | "retrying\n", res->lockname.len, |
2711 | res->lockname.name); |
2712 | msleep(DLM_MIGRATION_RETRY_MS); |
2713 | } |
2714 | spin_lock(&dlm->spinlock); |
2715 | leave: |
2716 | return lock_dropped; |
2717 | } |
2718 | |
2719 | int dlm_lock_basts_flushed(struct dlm_ctxt *dlm, struct dlm_lock *lock) |
2720 | { |
2721 | int ret; |
2722 | spin_lock(&dlm->ast_lock); |
2723 | spin_lock(&lock->spinlock); |
2724 | ret = (list_empty(&lock->bast_list) && !lock->bast_pending); |
2725 | spin_unlock(&lock->spinlock); |
2726 | spin_unlock(&dlm->ast_lock); |
2727 | return ret; |
2728 | } |
2729 | |
2730 | static int dlm_migration_can_proceed(struct dlm_ctxt *dlm, |
2731 | struct dlm_lock_resource *res, |
2732 | u8 mig_target) |
2733 | { |
2734 | int can_proceed; |
2735 | spin_lock(&res->spinlock); |
2736 | can_proceed = !!(res->state & DLM_LOCK_RES_MIGRATING); |
2737 | spin_unlock(&res->spinlock); |
2738 | |
2739 | /* target has died, so make the caller break out of the |
2740 | * wait_event, but caller must recheck the domain_map */ |
2741 | spin_lock(&dlm->spinlock); |
2742 | if (!test_bit(mig_target, dlm->domain_map)) |
2743 | can_proceed = 1; |
2744 | spin_unlock(&dlm->spinlock); |
2745 | return can_proceed; |
2746 | } |
2747 | |
2748 | static int dlm_lockres_is_dirty(struct dlm_ctxt *dlm, |
2749 | struct dlm_lock_resource *res) |
2750 | { |
2751 | int ret; |
2752 | spin_lock(&res->spinlock); |
2753 | ret = !!(res->state & DLM_LOCK_RES_DIRTY); |
2754 | spin_unlock(&res->spinlock); |
2755 | return ret; |
2756 | } |
2757 | |
2758 | |
2759 | static int dlm_mark_lockres_migrating(struct dlm_ctxt *dlm, |
2760 | struct dlm_lock_resource *res, |
2761 | u8 target) |
2762 | { |
2763 | int ret = 0; |
2764 | |
2765 | mlog(0, "dlm_mark_lockres_migrating: %.*s, from %u to %u\n", |
2766 | res->lockname.len, res->lockname.name, dlm->node_num, |
2767 | target); |
2768 | /* need to set MIGRATING flag on lockres. this is done by |
2769 | * ensuring that all asts have been flushed for this lockres. */ |
2770 | spin_lock(&res->spinlock); |
2771 | BUG_ON(res->migration_pending); |
2772 | res->migration_pending = 1; |
2773 | /* strategy is to reserve an extra ast then release |
2774 | * it below, letting the release do all of the work */ |
2775 | __dlm_lockres_reserve_ast(res); |
2776 | spin_unlock(&res->spinlock); |
2777 | |
2778 | /* now flush all the pending asts */ |
2779 | dlm_kick_thread(dlm, res); |
2780 | /* before waiting on DIRTY, block processes which may |
2781 | * try to dirty the lockres before MIGRATING is set */ |
2782 | spin_lock(&res->spinlock); |
2783 | BUG_ON(res->state & DLM_LOCK_RES_BLOCK_DIRTY); |
2784 | res->state |= DLM_LOCK_RES_BLOCK_DIRTY; |
2785 | spin_unlock(&res->spinlock); |
2786 | /* now wait on any pending asts and the DIRTY state */ |
2787 | wait_event(dlm->ast_wq, !dlm_lockres_is_dirty(dlm, res)); |
2788 | dlm_lockres_release_ast(dlm, res); |
2789 | |
2790 | mlog(0, "about to wait on migration_wq, dirty=%s\n", |
2791 | res->state & DLM_LOCK_RES_DIRTY ? "yes" : "no"); |
2792 | /* if the extra ref we just put was the final one, this |
2793 | * will pass thru immediately. otherwise, we need to wait |
2794 | * for the last ast to finish. */ |
2795 | again: |
2796 | ret = wait_event_interruptible_timeout(dlm->migration_wq, |
2797 | dlm_migration_can_proceed(dlm, res, target), |
2798 | msecs_to_jiffies(1000)); |
2799 | if (ret < 0) { |
2800 | mlog(0, "woken again: migrating? %s, dead? %s\n", |
2801 | res->state & DLM_LOCK_RES_MIGRATING ? "yes":"no", |
2802 | test_bit(target, dlm->domain_map) ? "no":"yes"); |
2803 | } else { |
2804 | mlog(0, "all is well: migrating? %s, dead? %s\n", |
2805 | res->state & DLM_LOCK_RES_MIGRATING ? "yes":"no", |
2806 | test_bit(target, dlm->domain_map) ? "no":"yes"); |
2807 | } |
2808 | if (!dlm_migration_can_proceed(dlm, res, target)) { |
2809 | mlog(0, "trying again...\n"); |
2810 | goto again; |
2811 | } |
2812 | /* now that we are sure the MIGRATING state is there, drop |
2813 | * the unneded state which blocked threads trying to DIRTY */ |
2814 | spin_lock(&res->spinlock); |
2815 | BUG_ON(!(res->state & DLM_LOCK_RES_BLOCK_DIRTY)); |
2816 | BUG_ON(!(res->state & DLM_LOCK_RES_MIGRATING)); |
2817 | res->state &= ~DLM_LOCK_RES_BLOCK_DIRTY; |
2818 | spin_unlock(&res->spinlock); |
2819 | |
2820 | /* did the target go down or die? */ |
2821 | spin_lock(&dlm->spinlock); |
2822 | if (!test_bit(target, dlm->domain_map)) { |
2823 | mlog(ML_ERROR, "aha. migration target %u just went down\n", |
2824 | target); |
2825 | ret = -EHOSTDOWN; |
2826 | } |
2827 | spin_unlock(&dlm->spinlock); |
2828 | |
2829 | /* |
2830 | * at this point: |
2831 | * |
2832 | * o the DLM_LOCK_RES_MIGRATING flag is set |
2833 | * o there are no pending asts on this lockres |
2834 | * o all processes trying to reserve an ast on this |
2835 | * lockres must wait for the MIGRATING flag to clear |
2836 | */ |
2837 | return ret; |
2838 | } |
2839 | |
2840 | /* last step in the migration process. |
2841 | * original master calls this to free all of the dlm_lock |
2842 | * structures that used to be for other nodes. */ |
2843 | static void dlm_remove_nonlocal_locks(struct dlm_ctxt *dlm, |
2844 | struct dlm_lock_resource *res) |
2845 | { |
2846 | struct list_head *queue = &res->granted; |
2847 | int i, bit; |
2848 | struct dlm_lock *lock, *next; |
2849 | |
2850 | assert_spin_locked(&res->spinlock); |
2851 | |
2852 | BUG_ON(res->owner == dlm->node_num); |
2853 | |
2854 | for (i=0; i<3; i++) { |
2855 | list_for_each_entry_safe(lock, next, queue, list) { |
2856 | if (lock->ml.node != dlm->node_num) { |
2857 | mlog(0, "putting lock for node %u\n", |
2858 | lock->ml.node); |
2859 | /* be extra careful */ |
2860 | BUG_ON(!list_empty(&lock->ast_list)); |
2861 | BUG_ON(!list_empty(&lock->bast_list)); |
2862 | BUG_ON(lock->ast_pending); |
2863 | BUG_ON(lock->bast_pending); |
2864 | dlm_lockres_clear_refmap_bit(lock->ml.node, res); |
2865 | list_del_init(&lock->list); |
2866 | dlm_lock_put(lock); |
2867 | /* In a normal unlock, we would have added a |
2868 | * DLM_UNLOCK_FREE_LOCK action. Force it. */ |
2869 | dlm_lock_put(lock); |
2870 | } |
2871 | } |
2872 | queue++; |
2873 | } |
2874 | bit = 0; |
2875 | while (1) { |
2876 | bit = find_next_bit(res->refmap, O2NM_MAX_NODES, bit); |
2877 | if (bit >= O2NM_MAX_NODES) |
2878 | break; |
2879 | /* do not clear the local node reference, if there is a |
2880 | * process holding this, let it drop the ref itself */ |
2881 | if (bit != dlm->node_num) { |
2882 | mlog(0, "%s:%.*s: node %u had a ref to this " |
2883 | "migrating lockres, clearing\n", dlm->name, |
2884 | res->lockname.len, res->lockname.name, bit); |
2885 | dlm_lockres_clear_refmap_bit(bit, res); |
2886 | } |
2887 | bit++; |
2888 | } |
2889 | } |
2890 | |
2891 | /* for now this is not too intelligent. we will |
2892 | * need stats to make this do the right thing. |
2893 | * this just finds the first lock on one of the |
2894 | * queues and uses that node as the target. */ |
2895 | static u8 dlm_pick_migration_target(struct dlm_ctxt *dlm, |
2896 | struct dlm_lock_resource *res) |
2897 | { |
2898 | int i; |
2899 | struct list_head *queue = &res->granted; |
2900 | struct dlm_lock *lock; |
2901 | int nodenum; |
2902 | |
2903 | assert_spin_locked(&dlm->spinlock); |
2904 | |
2905 | spin_lock(&res->spinlock); |
2906 | for (i=0; i<3; i++) { |
2907 | list_for_each_entry(lock, queue, list) { |
2908 | /* up to the caller to make sure this node |
2909 | * is alive */ |
2910 | if (lock->ml.node != dlm->node_num) { |
2911 | spin_unlock(&res->spinlock); |
2912 | return lock->ml.node; |
2913 | } |
2914 | } |
2915 | queue++; |
2916 | } |
2917 | spin_unlock(&res->spinlock); |
2918 | mlog(0, "have not found a suitable target yet! checking domain map\n"); |
2919 | |
2920 | /* ok now we're getting desperate. pick anyone alive. */ |
2921 | nodenum = -1; |
2922 | while (1) { |
2923 | nodenum = find_next_bit(dlm->domain_map, |
2924 | O2NM_MAX_NODES, nodenum+1); |
2925 | mlog(0, "found %d in domain map\n", nodenum); |
2926 | if (nodenum >= O2NM_MAX_NODES) |
2927 | break; |
2928 | if (nodenum != dlm->node_num) { |
2929 | mlog(0, "picking %d\n", nodenum); |
2930 | return nodenum; |
2931 | } |
2932 | } |
2933 | |
2934 | mlog(0, "giving up. no master to migrate to\n"); |
2935 | return DLM_LOCK_RES_OWNER_UNKNOWN; |
2936 | } |
2937 | |
2938 | |
2939 | |
2940 | /* this is called by the new master once all lockres |
2941 | * data has been received */ |
2942 | static int dlm_do_migrate_request(struct dlm_ctxt *dlm, |
2943 | struct dlm_lock_resource *res, |
2944 | u8 master, u8 new_master, |
2945 | struct dlm_node_iter *iter) |
2946 | { |
2947 | struct dlm_migrate_request migrate; |
2948 | int ret, skip, status = 0; |
2949 | int nodenum; |
2950 | |
2951 | memset(&migrate, 0, sizeof(migrate)); |
2952 | migrate.namelen = res->lockname.len; |
2953 | memcpy(migrate.name, res->lockname.name, migrate.namelen); |
2954 | migrate.new_master = new_master; |
2955 | migrate.master = master; |
2956 | |
2957 | ret = 0; |
2958 | |
2959 | /* send message to all nodes, except the master and myself */ |
2960 | while ((nodenum = dlm_node_iter_next(iter)) >= 0) { |
2961 | if (nodenum == master || |
2962 | nodenum == new_master) |
2963 | continue; |
2964 | |
2965 | /* We could race exit domain. If exited, skip. */ |
2966 | spin_lock(&dlm->spinlock); |
2967 | skip = (!test_bit(nodenum, dlm->domain_map)); |
2968 | spin_unlock(&dlm->spinlock); |
2969 | if (skip) { |
2970 | clear_bit(nodenum, iter->node_map); |
2971 | continue; |
2972 | } |
2973 | |
2974 | ret = o2net_send_message(DLM_MIGRATE_REQUEST_MSG, dlm->key, |
2975 | &migrate, sizeof(migrate), nodenum, |
2976 | &status); |
2977 | if (ret < 0) { |
2978 | mlog(0, "migrate_request returned %d!\n", ret); |
2979 | if (!dlm_is_host_down(ret)) { |
2980 | mlog(ML_ERROR, "unhandled error=%d!\n", ret); |
2981 | BUG(); |
2982 | } |
2983 | clear_bit(nodenum, iter->node_map); |
2984 | ret = 0; |
2985 | } else if (status < 0) { |
2986 | mlog(0, "migrate request (node %u) returned %d!\n", |
2987 | nodenum, status); |
2988 | ret = status; |
2989 | } else if (status == DLM_MIGRATE_RESPONSE_MASTERY_REF) { |
2990 | /* during the migration request we short-circuited |
2991 | * the mastery of the lockres. make sure we have |
2992 | * a mastery ref for nodenum */ |
2993 | mlog(0, "%s:%.*s: need ref for node %u\n", |
2994 | dlm->name, res->lockname.len, res->lockname.name, |
2995 | nodenum); |
2996 | spin_lock(&res->spinlock); |
2997 | dlm_lockres_set_refmap_bit(nodenum, res); |
2998 | spin_unlock(&res->spinlock); |
2999 | } |
3000 | } |
3001 | |
3002 | if (ret < 0) |
3003 | mlog_errno(ret); |
3004 | |
3005 | mlog(0, "returning ret=%d\n", ret); |
3006 | return ret; |
3007 | } |
3008 | |
3009 | |
3010 | /* if there is an existing mle for this lockres, we now know who the master is. |
3011 | * (the one who sent us *this* message) we can clear it up right away. |
3012 | * since the process that put the mle on the list still has a reference to it, |
3013 | * we can unhash it now, set the master and wake the process. as a result, |
3014 | * we will have no mle in the list to start with. now we can add an mle for |
3015 | * the migration and this should be the only one found for those scanning the |
3016 | * list. */ |
3017 | int dlm_migrate_request_handler(struct o2net_msg *msg, u32 len, void *data, |
3018 | void **ret_data) |
3019 | { |
3020 | struct dlm_ctxt *dlm = data; |
3021 | struct dlm_lock_resource *res = NULL; |
3022 | struct dlm_migrate_request *migrate = (struct dlm_migrate_request *) msg->buf; |
3023 | struct dlm_master_list_entry *mle = NULL, *oldmle = NULL; |
3024 | const char *name; |
3025 | unsigned int namelen, hash; |
3026 | int ret = 0; |
3027 | |
3028 | if (!dlm_grab(dlm)) |
3029 | return -EINVAL; |
3030 | |
3031 | name = migrate->name; |
3032 | namelen = migrate->namelen; |
3033 | hash = dlm_lockid_hash(name, namelen); |
3034 | |
3035 | /* preallocate.. if this fails, abort */ |
3036 | mle = (struct dlm_master_list_entry *) kmem_cache_alloc(dlm_mle_cache, |
3037 | GFP_NOFS); |
3038 | |
3039 | if (!mle) { |
3040 | ret = -ENOMEM; |
3041 | goto leave; |
3042 | } |
3043 | |
3044 | /* check for pre-existing lock */ |
3045 | spin_lock(&dlm->spinlock); |
3046 | res = __dlm_lookup_lockres(dlm, name, namelen, hash); |
3047 | spin_lock(&dlm->master_lock); |
3048 | |
3049 | if (res) { |
3050 | spin_lock(&res->spinlock); |
3051 | if (res->state & DLM_LOCK_RES_RECOVERING) { |
3052 | /* if all is working ok, this can only mean that we got |
3053 | * a migrate request from a node that we now see as |
3054 | * dead. what can we do here? drop it to the floor? */ |
3055 | spin_unlock(&res->spinlock); |
3056 | mlog(ML_ERROR, "Got a migrate request, but the " |
3057 | "lockres is marked as recovering!"); |
3058 | kmem_cache_free(dlm_mle_cache, mle); |
3059 | ret = -EINVAL; /* need a better solution */ |
3060 | goto unlock; |
3061 | } |
3062 | res->state |= DLM_LOCK_RES_MIGRATING; |
3063 | spin_unlock(&res->spinlock); |
3064 | } |
3065 | |
3066 | /* ignore status. only nonzero status would BUG. */ |
3067 | ret = dlm_add_migration_mle(dlm, res, mle, &oldmle, |
3068 | name, namelen, |
3069 | migrate->new_master, |
3070 | migrate->master); |
3071 | |
3072 | unlock: |
3073 | spin_unlock(&dlm->master_lock); |
3074 | spin_unlock(&dlm->spinlock); |
3075 | |
3076 | if (oldmle) { |
3077 | /* master is known, detach if not already detached */ |
3078 | dlm_mle_detach_hb_events(dlm, oldmle); |
3079 | dlm_put_mle(oldmle); |
3080 | } |
3081 | |
3082 | if (res) |
3083 | dlm_lockres_put(res); |
3084 | leave: |
3085 | dlm_put(dlm); |
3086 | return ret; |
3087 | } |
3088 | |
3089 | /* must be holding dlm->spinlock and dlm->master_lock |
3090 | * when adding a migration mle, we can clear any other mles |
3091 | * in the master list because we know with certainty that |
3092 | * the master is "master". so we remove any old mle from |
3093 | * the list after setting it's master field, and then add |
3094 | * the new migration mle. this way we can hold with the rule |
3095 | * of having only one mle for a given lock name at all times. */ |
3096 | static int dlm_add_migration_mle(struct dlm_ctxt *dlm, |
3097 | struct dlm_lock_resource *res, |
3098 | struct dlm_master_list_entry *mle, |
3099 | struct dlm_master_list_entry **oldmle, |
3100 | const char *name, unsigned int namelen, |
3101 | u8 new_master, u8 master) |
3102 | { |
3103 | int found; |
3104 | int ret = 0; |
3105 | |
3106 | *oldmle = NULL; |
3107 | |
3108 | mlog_entry_void(); |
3109 | |
3110 | assert_spin_locked(&dlm->spinlock); |
3111 | assert_spin_locked(&dlm->master_lock); |
3112 | |
3113 | /* caller is responsible for any ref taken here on oldmle */ |
3114 | found = dlm_find_mle(dlm, oldmle, (char *)name, namelen); |
3115 | if (found) { |
3116 | struct dlm_master_list_entry *tmp = *oldmle; |
3117 | spin_lock(&tmp->spinlock); |
3118 | if (tmp->type == DLM_MLE_MIGRATION) { |
3119 | if (master == dlm->node_num) { |
3120 | /* ah another process raced me to it */ |
3121 | mlog(0, "tried to migrate %.*s, but some " |
3122 | "process beat me to it\n", |
3123 | namelen, name); |
3124 | ret = -EEXIST; |
3125 | } else { |
3126 | /* bad. 2 NODES are trying to migrate! */ |
3127 | mlog(ML_ERROR, "migration error mle: " |
3128 | "master=%u new_master=%u // request: " |
3129 | "master=%u new_master=%u // " |
3130 | "lockres=%.*s\n", |
3131 | tmp->master, tmp->new_master, |
3132 | master, new_master, |
3133 | namelen, name); |
3134 | BUG(); |
3135 | } |
3136 | } else { |
3137 | /* this is essentially what assert_master does */ |
3138 | tmp->master = master; |
3139 | atomic_set(&tmp->woken, 1); |
3140 | wake_up(&tmp->wq); |
3141 | /* remove it so that only one mle will be found */ |
3142 | __dlm_unlink_mle(dlm, tmp); |
3143 | __dlm_mle_detach_hb_events(dlm, tmp); |
3144 | ret = DLM_MIGRATE_RESPONSE_MASTERY_REF; |
3145 | mlog(0, "%s:%.*s: master=%u, newmaster=%u, " |
3146 | "telling master to get ref for cleared out mle " |
3147 | "during migration\n", dlm->name, namelen, name, |
3148 | master, new_master); |
3149 | } |
3150 | spin_unlock(&tmp->spinlock); |
3151 | } |
3152 | |
3153 | /* now add a migration mle to the tail of the list */ |
3154 | dlm_init_mle(mle, DLM_MLE_MIGRATION, dlm, res, name, namelen); |
3155 | mle->new_master = new_master; |
3156 | /* the new master will be sending an assert master for this. |
3157 | * at that point we will get the refmap reference */ |
3158 | mle->master = master; |
3159 | /* do this for consistency with other mle types */ |
3160 | set_bit(new_master, mle->maybe_map); |
3161 | __dlm_insert_mle(dlm, mle); |
3162 | |
3163 | return ret; |
3164 | } |
3165 | |
3166 | /* |
3167 | * Sets the owner of the lockres, associated to the mle, to UNKNOWN |
3168 | */ |
3169 | static struct dlm_lock_resource *dlm_reset_mleres_owner(struct dlm_ctxt *dlm, |
3170 | struct dlm_master_list_entry *mle) |
3171 | { |
3172 | struct dlm_lock_resource *res; |
3173 | |
3174 | /* Find the lockres associated to the mle and set its owner to UNK */ |
3175 | res = __dlm_lookup_lockres(dlm, mle->mname, mle->mnamelen, |
3176 | mle->mnamehash); |
3177 | if (res) { |
3178 | spin_unlock(&dlm->master_lock); |
3179 | |
3180 | /* move lockres onto recovery list */ |
3181 | spin_lock(&res->spinlock); |
3182 | dlm_set_lockres_owner(dlm, res, DLM_LOCK_RES_OWNER_UNKNOWN); |
3183 | dlm_move_lockres_to_recovery_list(dlm, res); |
3184 | spin_unlock(&res->spinlock); |
3185 | dlm_lockres_put(res); |
3186 | |
3187 | /* about to get rid of mle, detach from heartbeat */ |
3188 | __dlm_mle_detach_hb_events(dlm, mle); |
3189 | |
3190 | /* dump the mle */ |
3191 | spin_lock(&dlm->master_lock); |
3192 | __dlm_put_mle(mle); |
3193 | spin_unlock(&dlm->master_lock); |
3194 | } |
3195 | |
3196 | return res; |
3197 | } |
3198 | |
3199 | static void dlm_clean_migration_mle(struct dlm_ctxt *dlm, |
3200 | struct dlm_master_list_entry *mle) |
3201 | { |
3202 | __dlm_mle_detach_hb_events(dlm, mle); |
3203 | |
3204 | spin_lock(&mle->spinlock); |
3205 | __dlm_unlink_mle(dlm, mle); |
3206 | atomic_set(&mle->woken, 1); |
3207 | spin_unlock(&mle->spinlock); |
3208 | |
3209 | wake_up(&mle->wq); |
3210 | } |
3211 | |
3212 | static void dlm_clean_block_mle(struct dlm_ctxt *dlm, |
3213 | struct dlm_master_list_entry *mle, u8 dead_node) |
3214 | { |
3215 | int bit; |
3216 | |
3217 | BUG_ON(mle->type != DLM_MLE_BLOCK); |
3218 | |
3219 | spin_lock(&mle->spinlock); |
3220 | bit = find_next_bit(mle->maybe_map, O2NM_MAX_NODES, 0); |
3221 | if (bit != dead_node) { |
3222 | mlog(0, "mle found, but dead node %u would not have been " |
3223 | "master\n", dead_node); |
3224 | spin_unlock(&mle->spinlock); |
3225 | } else { |
3226 | /* Must drop the refcount by one since the assert_master will |
3227 | * never arrive. This may result in the mle being unlinked and |
3228 | * freed, but there may still be a process waiting in the |
3229 | * dlmlock path which is fine. */ |
3230 | mlog(0, "node %u was expected master\n", dead_node); |
3231 | atomic_set(&mle->woken, 1); |
3232 | spin_unlock(&mle->spinlock); |
3233 | wake_up(&mle->wq); |
3234 | |
3235 | /* Do not need events any longer, so detach from heartbeat */ |
3236 | __dlm_mle_detach_hb_events(dlm, mle); |
3237 | __dlm_put_mle(mle); |
3238 | } |
3239 | } |
3240 | |
3241 | void dlm_clean_master_list(struct dlm_ctxt *dlm, u8 dead_node) |
3242 | { |
3243 | struct dlm_master_list_entry *mle; |
3244 | struct dlm_lock_resource *res; |
3245 | struct hlist_head *bucket; |
3246 | struct hlist_node *list; |
3247 | unsigned int i; |
3248 | |
3249 | mlog_entry("dlm=%s, dead node=%u\n", dlm->name, dead_node); |
3250 | top: |
3251 | assert_spin_locked(&dlm->spinlock); |
3252 | |
3253 | /* clean the master list */ |
3254 | spin_lock(&dlm->master_lock); |
3255 | for (i = 0; i < DLM_HASH_BUCKETS; i++) { |
3256 | bucket = dlm_master_hash(dlm, i); |
3257 | hlist_for_each(list, bucket) { |
3258 | mle = hlist_entry(list, struct dlm_master_list_entry, |
3259 | master_hash_node); |
3260 | |
3261 | BUG_ON(mle->type != DLM_MLE_BLOCK && |
3262 | mle->type != DLM_MLE_MASTER && |
3263 | mle->type != DLM_MLE_MIGRATION); |
3264 | |
3265 | /* MASTER mles are initiated locally. The waiting |
3266 | * process will notice the node map change shortly. |
3267 | * Let that happen as normal. */ |
3268 | if (mle->type == DLM_MLE_MASTER) |
3269 | continue; |
3270 | |
3271 | /* BLOCK mles are initiated by other nodes. Need to |
3272 | * clean up if the dead node would have been the |
3273 | * master. */ |
3274 | if (mle->type == DLM_MLE_BLOCK) { |
3275 | dlm_clean_block_mle(dlm, mle, dead_node); |
3276 | continue; |
3277 | } |
3278 | |
3279 | /* Everything else is a MIGRATION mle */ |
3280 | |
3281 | /* The rule for MIGRATION mles is that the master |
3282 | * becomes UNKNOWN if *either* the original or the new |
3283 | * master dies. All UNKNOWN lockres' are sent to |
3284 | * whichever node becomes the recovery master. The new |
3285 | * master is responsible for determining if there is |
3286 | * still a master for this lockres, or if he needs to |
3287 | * take over mastery. Either way, this node should |
3288 | * expect another message to resolve this. */ |
3289 | |
3290 | if (mle->master != dead_node && |
3291 | mle->new_master != dead_node) |
3292 | continue; |
3293 | |
3294 | /* If we have reached this point, this mle needs to be |
3295 | * removed from the list and freed. */ |
3296 | dlm_clean_migration_mle(dlm, mle); |
3297 | |
3298 | mlog(0, "%s: node %u died during migration from " |
3299 | "%u to %u!\n", dlm->name, dead_node, mle->master, |
3300 | mle->new_master); |
3301 | |
3302 | /* If we find a lockres associated with the mle, we've |
3303 | * hit this rare case that messes up our lock ordering. |
3304 | * If so, we need to drop the master lock so that we can |
3305 | * take the lockres lock, meaning that we will have to |
3306 | * restart from the head of list. */ |
3307 | res = dlm_reset_mleres_owner(dlm, mle); |
3308 | if (res) |
3309 | /* restart */ |
3310 | goto top; |
3311 | |
3312 | /* This may be the last reference */ |
3313 | __dlm_put_mle(mle); |
3314 | } |
3315 | } |
3316 | spin_unlock(&dlm->master_lock); |
3317 | } |
3318 | |
3319 | int dlm_finish_migration(struct dlm_ctxt *dlm, struct dlm_lock_resource *res, |
3320 | u8 old_master) |
3321 | { |
3322 | struct dlm_node_iter iter; |
3323 | int ret = 0; |
3324 | |
3325 | spin_lock(&dlm->spinlock); |
3326 | dlm_node_iter_init(dlm->domain_map, &iter); |
3327 | clear_bit(old_master, iter.node_map); |
3328 | clear_bit(dlm->node_num, iter.node_map); |
3329 | spin_unlock(&dlm->spinlock); |
3330 | |
3331 | /* ownership of the lockres is changing. account for the |
3332 | * mastery reference here since old_master will briefly have |
3333 | * a reference after the migration completes */ |
3334 | spin_lock(&res->spinlock); |
3335 | dlm_lockres_set_refmap_bit(old_master, res); |
3336 | spin_unlock(&res->spinlock); |
3337 | |
3338 | mlog(0, "now time to do a migrate request to other nodes\n"); |
3339 | ret = dlm_do_migrate_request(dlm, res, old_master, |
3340 | dlm->node_num, &iter); |
3341 | if (ret < 0) { |
3342 | mlog_errno(ret); |
3343 | goto leave; |
3344 | } |
3345 | |
3346 | mlog(0, "doing assert master of %.*s to all except the original node\n", |
3347 | res->lockname.len, res->lockname.name); |
3348 | /* this call now finishes out the nodemap |
3349 | * even if one or more nodes die */ |
3350 | ret = dlm_do_assert_master(dlm, res, iter.node_map, |
3351 | DLM_ASSERT_MASTER_FINISH_MIGRATION); |
3352 | if (ret < 0) { |
3353 | /* no longer need to retry. all living nodes contacted. */ |
3354 | mlog_errno(ret); |
3355 | ret = 0; |
3356 | } |
3357 | |
3358 | memset(iter.node_map, 0, sizeof(iter.node_map)); |
3359 | set_bit(old_master, iter.node_map); |
3360 | mlog(0, "doing assert master of %.*s back to %u\n", |
3361 | res->lockname.len, res->lockname.name, old_master); |
3362 | ret = dlm_do_assert_master(dlm, res, iter.node_map, |
3363 | DLM_ASSERT_MASTER_FINISH_MIGRATION); |
3364 | if (ret < 0) { |
3365 | mlog(0, "assert master to original master failed " |
3366 | "with %d.\n", ret); |
3367 | /* the only nonzero status here would be because of |
3368 | * a dead original node. we're done. */ |
3369 | ret = 0; |
3370 | } |
3371 | |
3372 | /* all done, set the owner, clear the flag */ |
3373 | spin_lock(&res->spinlock); |
3374 | dlm_set_lockres_owner(dlm, res, dlm->node_num); |
3375 | res->state &= ~DLM_LOCK_RES_MIGRATING; |
3376 | spin_unlock(&res->spinlock); |
3377 | /* re-dirty it on the new master */ |
3378 | dlm_kick_thread(dlm, res); |
3379 | wake_up(&res->wq); |
3380 | leave: |
3381 | return ret; |
3382 | } |
3383 | |
3384 | /* |
3385 | * LOCKRES AST REFCOUNT |
3386 | * this is integral to migration |
3387 | */ |
3388 | |
3389 | /* for future intent to call an ast, reserve one ahead of time. |
3390 | * this should be called only after waiting on the lockres |
3391 | * with dlm_wait_on_lockres, and while still holding the |
3392 | * spinlock after the call. */ |
3393 | void __dlm_lockres_reserve_ast(struct dlm_lock_resource *res) |
3394 | { |
3395 | assert_spin_locked(&res->spinlock); |
3396 | if (res->state & DLM_LOCK_RES_MIGRATING) { |
3397 | __dlm_print_one_lock_resource(res); |
3398 | } |
3399 | BUG_ON(res->state & DLM_LOCK_RES_MIGRATING); |
3400 | |
3401 | atomic_inc(&res->asts_reserved); |
3402 | } |
3403 | |
3404 | /* |
3405 | * used to drop the reserved ast, either because it went unused, |
3406 | * or because the ast/bast was actually called. |
3407 | * |
3408 | * also, if there is a pending migration on this lockres, |
3409 | * and this was the last pending ast on the lockres, |
3410 | * atomically set the MIGRATING flag before we drop the lock. |
3411 | * this is how we ensure that migration can proceed with no |
3412 | * asts in progress. note that it is ok if the state of the |
3413 | * queues is such that a lock should be granted in the future |
3414 | * or that a bast should be fired, because the new master will |
3415 | * shuffle the lists on this lockres as soon as it is migrated. |
3416 | */ |
3417 | void dlm_lockres_release_ast(struct dlm_ctxt *dlm, |
3418 | struct dlm_lock_resource *res) |
3419 | { |
3420 | if (!atomic_dec_and_lock(&res->asts_reserved, &res->spinlock)) |
3421 | return; |
3422 | |
3423 | if (!res->migration_pending) { |
3424 | spin_unlock(&res->spinlock); |
3425 | return; |
3426 | } |
3427 | |
3428 | BUG_ON(res->state & DLM_LOCK_RES_MIGRATING); |
3429 | res->migration_pending = 0; |
3430 | res->state |= DLM_LOCK_RES_MIGRATING; |
3431 | spin_unlock(&res->spinlock); |
3432 | wake_up(&res->wq); |
3433 | wake_up(&dlm->migration_wq); |
3434 | } |
3435 |
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Tags:
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v2.6.34-rc5
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