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. */
dlm_should_cancel_bast(struct dlm_ctxt * dlm,struct dlm_lock * lock)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 
__dlm_queue_ast(struct dlm_ctxt * dlm,struct dlm_lock * lock)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 
dlm_queue_ast(struct dlm_ctxt * dlm,struct dlm_lock * lock)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 
__dlm_queue_bast(struct dlm_ctxt * dlm,struct dlm_lock * lock)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 
dlm_queue_bast(struct dlm_ctxt * dlm,struct dlm_lock * lock)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 
dlm_update_lvb(struct dlm_ctxt * dlm,struct dlm_lock_resource * res,struct dlm_lock * lock)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 
dlm_do_local_ast(struct dlm_ctxt * dlm,struct dlm_lock_resource * res,struct dlm_lock * lock)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 
dlm_do_remote_ast(struct dlm_ctxt * dlm,struct dlm_lock_resource * res,struct dlm_lock * lock)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 
dlm_do_local_bast(struct dlm_ctxt * dlm,struct dlm_lock_resource * res,struct dlm_lock * lock,int blocked_type)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 
dlm_proxy_ast_handler(struct o2net_msg * msg,u32 len,void * data,void ** ret_data)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 
dlm_send_proxy_ast_msg(struct dlm_ctxt * dlm,struct dlm_lock_resource * res,struct dlm_lock * lock,int msg_type,int blocked_type,int flags)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