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TOMOYO Linux Cross Reference
Linux/fs/ocfs2/dlm/dlmast.c

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  1 /* -*- mode: c; c-basic-offset: 8; -*-
  2  * vim: noexpandtab sw=8 ts=8 sts=0:
  3  *
  4  * dlmast.c
  5  *
  6  * AST and BAST functionality for local and remote nodes
  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/highmem.h>
 32 #include <linux/init.h>
 33 #include <linux/sysctl.h>
 34 #include <linux/random.h>
 35 #include <linux/blkdev.h>
 36 #include <linux/socket.h>
 37 #include <linux/inet.h>
 38 #include <linux/spinlock.h>
 39 
 40 
 41 #include "cluster/heartbeat.h"
 42 #include "cluster/nodemanager.h"
 43 #include "cluster/tcp.h"
 44 
 45 #include "dlmapi.h"
 46 #include "dlmcommon.h"
 47 
 48 #define MLOG_MASK_PREFIX ML_DLM
 49 #include "cluster/masklog.h"
 50 
 51 static void dlm_update_lvb(struct dlm_ctxt *dlm, struct dlm_lock_resource *res,
 52                            struct dlm_lock *lock);
 53 static int dlm_should_cancel_bast(struct dlm_ctxt *dlm, struct dlm_lock *lock);
 54 
 55 /* Should be called as an ast gets queued to see if the new
 56  * lock level will obsolete a pending bast.
 57  * For example, if dlm_thread queued a bast for an EX lock that
 58  * was blocking another EX, but before sending the bast the
 59  * lock owner downconverted to NL, the bast is now obsolete.
 60  * Only the ast should be sent.
 61  * This is needed because the lock and convert paths can queue
 62  * asts out-of-band (not waiting for dlm_thread) in order to
 63  * allow for LKM_NOQUEUE to get immediate responses. */
 64 static int dlm_should_cancel_bast(struct dlm_ctxt *dlm, struct dlm_lock *lock)
 65 {
 66         assert_spin_locked(&dlm->ast_lock);
 67         assert_spin_locked(&lock->spinlock);
 68 
 69         if (lock->ml.highest_blocked == LKM_IVMODE)
 70                 return 0;
 71         BUG_ON(lock->ml.highest_blocked == LKM_NLMODE);
 72 
 73         if (lock->bast_pending &&
 74             list_empty(&lock->bast_list))
 75                 /* old bast already sent, ok */
 76                 return 0;
 77 
 78         if (lock->ml.type == LKM_EXMODE)
 79                 /* EX blocks anything left, any bast still valid */
 80                 return 0;
 81         else if (lock->ml.type == LKM_NLMODE)
 82                 /* NL blocks nothing, no reason to send any bast, cancel it */
 83                 return 1;
 84         else if (lock->ml.highest_blocked != LKM_EXMODE)
 85                 /* PR only blocks EX */
 86                 return 1;
 87 
 88         return 0;
 89 }
 90 
 91 void __dlm_queue_ast(struct dlm_ctxt *dlm, struct dlm_lock *lock)
 92 {
 93         struct dlm_lock_resource *res;
 94 
 95         BUG_ON(!dlm);
 96         BUG_ON(!lock);
 97 
 98         res = lock->lockres;
 99 
100         assert_spin_locked(&dlm->ast_lock);
101 
102         if (!list_empty(&lock->ast_list)) {
103                 mlog(ML_ERROR, "%s: res %.*s, lock %u:%llu, "
104                      "AST list not empty, pending %d, newlevel %d\n",
105                      dlm->name, res->lockname.len, res->lockname.name,
106                      dlm_get_lock_cookie_node(be64_to_cpu(lock->ml.cookie)),
107                      dlm_get_lock_cookie_seq(be64_to_cpu(lock->ml.cookie)),
108                      lock->ast_pending, lock->ml.type);
109                 BUG();
110         }
111         if (lock->ast_pending)
112                 mlog(0, "%s: res %.*s, lock %u:%llu, AST getting flushed\n",
113                      dlm->name, res->lockname.len, res->lockname.name,
114                      dlm_get_lock_cookie_node(be64_to_cpu(lock->ml.cookie)),
115                      dlm_get_lock_cookie_seq(be64_to_cpu(lock->ml.cookie)));
116 
117         /* putting lock on list, add a ref */
118         dlm_lock_get(lock);
119         spin_lock(&lock->spinlock);
120 
121         /* check to see if this ast obsoletes the bast */
122         if (dlm_should_cancel_bast(dlm, lock)) {
123                 mlog(0, "%s: res %.*s, lock %u:%llu, Cancelling BAST\n",
124                      dlm->name, res->lockname.len, res->lockname.name,
125                      dlm_get_lock_cookie_node(be64_to_cpu(lock->ml.cookie)),
126                      dlm_get_lock_cookie_seq(be64_to_cpu(lock->ml.cookie)));
127                 lock->bast_pending = 0;
128                 list_del_init(&lock->bast_list);
129                 lock->ml.highest_blocked = LKM_IVMODE;
130                 /* removing lock from list, remove a ref.  guaranteed
131                  * this won't be the last ref because of the get above,
132                  * so res->spinlock will not be taken here */
133                 dlm_lock_put(lock);
134                 /* free up the reserved bast that we are cancelling.
135                  * guaranteed that this will not be the last reserved
136                  * ast because *both* an ast and a bast were reserved
137                  * to get to this point.  the res->spinlock will not be
138                  * taken here */
139                 dlm_lockres_release_ast(dlm, res);
140         }
141         list_add_tail(&lock->ast_list, &dlm->pending_asts);
142         lock->ast_pending = 1;
143         spin_unlock(&lock->spinlock);
144 }
145 
146 void dlm_queue_ast(struct dlm_ctxt *dlm, struct dlm_lock *lock)
147 {
148         BUG_ON(!dlm);
149         BUG_ON(!lock);
150 
151         spin_lock(&dlm->ast_lock);
152         __dlm_queue_ast(dlm, lock);
153         spin_unlock(&dlm->ast_lock);
154 }
155 
156 
157 void __dlm_queue_bast(struct dlm_ctxt *dlm, struct dlm_lock *lock)
158 {
159         struct dlm_lock_resource *res;
160 
161         BUG_ON(!dlm);
162         BUG_ON(!lock);
163 
164         assert_spin_locked(&dlm->ast_lock);
165 
166         res = lock->lockres;
167 
168         BUG_ON(!list_empty(&lock->bast_list));
169         if (lock->bast_pending)
170                 mlog(0, "%s: res %.*s, lock %u:%llu, BAST getting flushed\n",
171                      dlm->name, res->lockname.len, res->lockname.name,
172                      dlm_get_lock_cookie_node(be64_to_cpu(lock->ml.cookie)),
173                      dlm_get_lock_cookie_seq(be64_to_cpu(lock->ml.cookie)));
174 
175         /* putting lock on list, add a ref */
176         dlm_lock_get(lock);
177         spin_lock(&lock->spinlock);
178         list_add_tail(&lock->bast_list, &dlm->pending_basts);
179         lock->bast_pending = 1;
180         spin_unlock(&lock->spinlock);
181 }
182 
183 void dlm_queue_bast(struct dlm_ctxt *dlm, struct dlm_lock *lock)
184 {
185         BUG_ON(!dlm);
186         BUG_ON(!lock);
187 
188         spin_lock(&dlm->ast_lock);
189         __dlm_queue_bast(dlm, lock);
190         spin_unlock(&dlm->ast_lock);
191 }
192 
193 static void dlm_update_lvb(struct dlm_ctxt *dlm, struct dlm_lock_resource *res,
194                            struct dlm_lock *lock)
195 {
196         struct dlm_lockstatus *lksb = lock->lksb;
197         BUG_ON(!lksb);
198 
199         /* only updates if this node masters the lockres */
200         spin_lock(&res->spinlock);
201         if (res->owner == dlm->node_num) {
202                 /* check the lksb flags for the direction */
203                 if (lksb->flags & DLM_LKSB_GET_LVB) {
204                         mlog(0, "getting lvb from lockres for %s node\n",
205                                   lock->ml.node == dlm->node_num ? "master" :
206                                   "remote");
207                         memcpy(lksb->lvb, res->lvb, DLM_LVB_LEN);
208                 }
209                 /* Do nothing for lvb put requests - they should be done in
210                  * place when the lock is downconverted - otherwise we risk
211                  * racing gets and puts which could result in old lvb data
212                  * being propagated. We leave the put flag set and clear it
213                  * here. In the future we might want to clear it at the time
214                  * the put is actually done.
215                  */
216         }
217         spin_unlock(&res->spinlock);
218 
219         /* reset any lvb flags on the lksb */
220         lksb->flags &= ~(DLM_LKSB_PUT_LVB|DLM_LKSB_GET_LVB);
221 }
222 
223 void dlm_do_local_ast(struct dlm_ctxt *dlm, struct dlm_lock_resource *res,
224                       struct dlm_lock *lock)
225 {
226         dlm_astlockfunc_t *fn;
227 
228         mlog(0, "%s: res %.*s, lock %u:%llu, Local AST\n", dlm->name,
229              res->lockname.len, res->lockname.name,
230              dlm_get_lock_cookie_node(be64_to_cpu(lock->ml.cookie)),
231              dlm_get_lock_cookie_seq(be64_to_cpu(lock->ml.cookie)));
232 
233         fn = lock->ast;
234         BUG_ON(lock->ml.node != dlm->node_num);
235 
236         dlm_update_lvb(dlm, res, lock);
237         (*fn)(lock->astdata);
238 }
239 
240 
241 int dlm_do_remote_ast(struct dlm_ctxt *dlm, struct dlm_lock_resource *res,
242                       struct dlm_lock *lock)
243 {
244         int ret;
245         struct dlm_lockstatus *lksb;
246         int lksbflags;
247 
248         mlog(0, "%s: res %.*s, lock %u:%llu, Remote AST\n", dlm->name,
249              res->lockname.len, res->lockname.name,
250              dlm_get_lock_cookie_node(be64_to_cpu(lock->ml.cookie)),
251              dlm_get_lock_cookie_seq(be64_to_cpu(lock->ml.cookie)));
252 
253         lksb = lock->lksb;
254         BUG_ON(lock->ml.node == dlm->node_num);
255 
256         lksbflags = lksb->flags;
257         dlm_update_lvb(dlm, res, lock);
258 
259         /* lock request came from another node
260          * go do the ast over there */
261         ret = dlm_send_proxy_ast(dlm, res, lock, lksbflags);
262         return ret;
263 }
264 
265 void dlm_do_local_bast(struct dlm_ctxt *dlm, struct dlm_lock_resource *res,
266                        struct dlm_lock *lock, int blocked_type)
267 {
268         dlm_bastlockfunc_t *fn = lock->bast;
269 
270         BUG_ON(lock->ml.node != dlm->node_num);
271 
272         mlog(0, "%s: res %.*s, lock %u:%llu, Local BAST, blocked %d\n",
273              dlm->name, res->lockname.len, res->lockname.name,
274              dlm_get_lock_cookie_node(be64_to_cpu(lock->ml.cookie)),
275              dlm_get_lock_cookie_seq(be64_to_cpu(lock->ml.cookie)),
276              blocked_type);
277 
278         (*fn)(lock->astdata, blocked_type);
279 }
280 
281 
282 
283 int dlm_proxy_ast_handler(struct o2net_msg *msg, u32 len, void *data,
284                           void **ret_data)
285 {
286         int ret;
287         unsigned int locklen;
288         struct dlm_ctxt *dlm = data;
289         struct dlm_lock_resource *res = NULL;
290         struct dlm_lock *lock = NULL;
291         struct dlm_proxy_ast *past = (struct dlm_proxy_ast *) msg->buf;
292         char *name;
293         struct list_head *head = NULL;
294         __be64 cookie;
295         u32 flags;
296         u8 node;
297 
298         if (!dlm_grab(dlm)) {
299                 dlm_error(DLM_REJECTED);
300                 return DLM_REJECTED;
301         }
302 
303         mlog_bug_on_msg(!dlm_domain_fully_joined(dlm),
304                         "Domain %s not fully joined!\n", dlm->name);
305 
306         name = past->name;
307         locklen = past->namelen;
308         cookie = past->cookie;
309         flags = be32_to_cpu(past->flags);
310         node = past->node_idx;
311 
312         if (locklen > DLM_LOCKID_NAME_MAX) {
313                 ret = DLM_IVBUFLEN;
314                 mlog(ML_ERROR, "Invalid name length (%d) in proxy ast "
315                      "handler!\n", locklen);
316                 goto leave;
317         }
318 
319         if ((flags & (LKM_PUT_LVB|LKM_GET_LVB)) ==
320              (LKM_PUT_LVB|LKM_GET_LVB)) {
321                 mlog(ML_ERROR, "Both PUT and GET lvb specified, (0x%x)\n",
322                      flags);
323                 ret = DLM_BADARGS;
324                 goto leave;
325         }
326 
327         mlog(0, "lvb: %s\n", flags & LKM_PUT_LVB ? "put lvb" :
328                   (flags & LKM_GET_LVB ? "get lvb" : "none"));
329 
330         mlog(0, "type=%d, blocked_type=%d\n", past->type, past->blocked_type);
331 
332         if (past->type != DLM_AST &&
333             past->type != DLM_BAST) {
334                 mlog(ML_ERROR, "Unknown ast type! %d, cookie=%u:%llu"
335                      "name=%.*s, node=%u\n", past->type,
336                      dlm_get_lock_cookie_node(be64_to_cpu(cookie)),
337                      dlm_get_lock_cookie_seq(be64_to_cpu(cookie)),
338                      locklen, name, node);
339                 ret = DLM_IVLOCKID;
340                 goto leave;
341         }
342 
343         res = dlm_lookup_lockres(dlm, name, locklen);
344         if (!res) {
345                 mlog(0, "Got %sast for unknown lockres! cookie=%u:%llu, "
346                      "name=%.*s, node=%u\n", (past->type == DLM_AST ? "" : "b"),
347                      dlm_get_lock_cookie_node(be64_to_cpu(cookie)),
348                      dlm_get_lock_cookie_seq(be64_to_cpu(cookie)),
349                      locklen, name, node);
350                 ret = DLM_IVLOCKID;
351                 goto leave;
352         }
353 
354         /* cannot get a proxy ast message if this node owns it */
355         BUG_ON(res->owner == dlm->node_num);
356 
357         mlog(0, "%s: res %.*s\n", dlm->name, res->lockname.len,
358              res->lockname.name);
359 
360         spin_lock(&res->spinlock);
361         if (res->state & DLM_LOCK_RES_RECOVERING) {
362                 mlog(0, "Responding with DLM_RECOVERING!\n");
363                 ret = DLM_RECOVERING;
364                 goto unlock_out;
365         }
366         if (res->state & DLM_LOCK_RES_MIGRATING) {
367                 mlog(0, "Responding with DLM_MIGRATING!\n");
368                 ret = DLM_MIGRATING;
369                 goto unlock_out;
370         }
371         /* try convert queue for both ast/bast */
372         head = &res->converting;
373         lock = NULL;
374         list_for_each_entry(lock, head, list) {
375                 if (lock->ml.cookie == cookie)
376                         goto do_ast;
377         }
378 
379         /* if not on convert, try blocked for ast, granted for bast */
380         if (past->type == DLM_AST)
381                 head = &res->blocked;
382         else
383                 head = &res->granted;
384 
385         list_for_each_entry(lock, head, list) {
386                 /* if lock is found but unlock is pending ignore the bast */
387                 if (lock->ml.cookie == cookie) {
388                         if (lock->unlock_pending)
389                                 break;
390                         goto do_ast;
391                 }
392         }
393 
394         mlog(0, "Got %sast for unknown lock! cookie=%u:%llu, name=%.*s, "
395              "node=%u\n", past->type == DLM_AST ? "" : "b",
396              dlm_get_lock_cookie_node(be64_to_cpu(cookie)),
397              dlm_get_lock_cookie_seq(be64_to_cpu(cookie)),
398              locklen, name, node);
399 
400         ret = DLM_NORMAL;
401 unlock_out:
402         spin_unlock(&res->spinlock);
403         goto leave;
404 
405 do_ast:
406         ret = DLM_NORMAL;
407         if (past->type == DLM_AST) {
408                 /* do not alter lock refcount.  switching lists. */
409                 list_move_tail(&lock->list, &res->granted);
410                 mlog(0, "%s: res %.*s, lock %u:%llu, Granted type %d => %d\n",
411                      dlm->name, res->lockname.len, res->lockname.name,
412                      dlm_get_lock_cookie_node(be64_to_cpu(cookie)),
413                      dlm_get_lock_cookie_seq(be64_to_cpu(cookie)),
414                      lock->ml.type, lock->ml.convert_type);
415 
416                 if (lock->ml.convert_type != LKM_IVMODE) {
417                         lock->ml.type = lock->ml.convert_type;
418                         lock->ml.convert_type = LKM_IVMODE;
419                 } else {
420                         // should already be there....
421                 }
422 
423                 lock->lksb->status = DLM_NORMAL;
424 
425                 /* if we requested the lvb, fetch it into our lksb now */
426                 if (flags & LKM_GET_LVB) {
427                         BUG_ON(!(lock->lksb->flags & DLM_LKSB_GET_LVB));
428                         memcpy(lock->lksb->lvb, past->lvb, DLM_LVB_LEN);
429                 }
430         }
431         spin_unlock(&res->spinlock);
432 
433         if (past->type == DLM_AST)
434                 dlm_do_local_ast(dlm, res, lock);
435         else
436                 dlm_do_local_bast(dlm, res, lock, past->blocked_type);
437 
438 leave:
439         if (res)
440                 dlm_lockres_put(res);
441 
442         dlm_put(dlm);
443         return ret;
444 }
445 
446 
447 
448 int dlm_send_proxy_ast_msg(struct dlm_ctxt *dlm, struct dlm_lock_resource *res,
449                            struct dlm_lock *lock, int msg_type,
450                            int blocked_type, int flags)
451 {
452         int ret = 0;
453         struct dlm_proxy_ast past;
454         struct kvec vec[2];
455         size_t veclen = 1;
456         int status;
457 
458         mlog(0, "%s: res %.*s, to %u, type %d, blocked_type %d\n", dlm->name,
459              res->lockname.len, res->lockname.name, lock->ml.node, msg_type,
460              blocked_type);
461 
462         memset(&past, 0, sizeof(struct dlm_proxy_ast));
463         past.node_idx = dlm->node_num;
464         past.type = msg_type;
465         past.blocked_type = blocked_type;
466         past.namelen = res->lockname.len;
467         memcpy(past.name, res->lockname.name, past.namelen);
468         past.cookie = lock->ml.cookie;
469 
470         vec[0].iov_len = sizeof(struct dlm_proxy_ast);
471         vec[0].iov_base = &past;
472         if (flags & DLM_LKSB_GET_LVB) {
473                 be32_add_cpu(&past.flags, LKM_GET_LVB);
474                 vec[1].iov_len = DLM_LVB_LEN;
475                 vec[1].iov_base = lock->lksb->lvb;
476                 veclen++;
477         }
478 
479         ret = o2net_send_message_vec(DLM_PROXY_AST_MSG, dlm->key, vec, veclen,
480                                      lock->ml.node, &status);
481         if (ret < 0)
482                 mlog(ML_ERROR, "%s: res %.*s, error %d send AST to node %u\n",
483                      dlm->name, res->lockname.len, res->lockname.name, ret,
484                      lock->ml.node);
485         else {
486                 if (status == DLM_RECOVERING) {
487                         mlog(ML_ERROR, "sent AST to node %u, it thinks this "
488                              "node is dead!\n", lock->ml.node);
489                         BUG();
490                 } else if (status == DLM_MIGRATING) {
491                         mlog(ML_ERROR, "sent AST to node %u, it returned "
492                              "DLM_MIGRATING!\n", lock->ml.node);
493                         BUG();
494                 } else if (status != DLM_NORMAL && status != DLM_IVLOCKID) {
495                         mlog(ML_ERROR, "AST to node %u returned %d!\n",
496                              lock->ml.node, status);
497                         /* ignore it */
498                 }
499                 ret = 0;
500         }
501         return ret;
502 }
503 

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