xref: /openbmc/linux/fs/ocfs2/dlm/dlmast.c (revision 7dd65feb)
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/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 
41 
42 #include "cluster/heartbeat.h"
43 #include "cluster/nodemanager.h"
44 #include "cluster/tcp.h"
45 
46 #include "dlmapi.h"
47 #include "dlmcommon.h"
48 
49 #define MLOG_MASK_PREFIX ML_DLM
50 #include "cluster/masklog.h"
51 
52 static void dlm_update_lvb(struct dlm_ctxt *dlm, struct dlm_lock_resource *res,
53 			   struct dlm_lock *lock);
54 static int dlm_should_cancel_bast(struct dlm_ctxt *dlm, struct dlm_lock *lock);
55 
56 /* Should be called as an ast gets queued to see if the new
57  * lock level will obsolete a pending bast.
58  * For example, if dlm_thread queued a bast for an EX lock that
59  * was blocking another EX, but before sending the bast the
60  * lock owner downconverted to NL, the bast is now obsolete.
61  * Only the ast should be sent.
62  * This is needed because the lock and convert paths can queue
63  * asts out-of-band (not waiting for dlm_thread) in order to
64  * allow for LKM_NOQUEUE to get immediate responses. */
65 static int dlm_should_cancel_bast(struct dlm_ctxt *dlm, struct dlm_lock *lock)
66 {
67 	assert_spin_locked(&dlm->ast_lock);
68 	assert_spin_locked(&lock->spinlock);
69 
70 	if (lock->ml.highest_blocked == LKM_IVMODE)
71 		return 0;
72 	BUG_ON(lock->ml.highest_blocked == LKM_NLMODE);
73 
74 	if (lock->bast_pending &&
75 	    list_empty(&lock->bast_list))
76 		/* old bast already sent, ok */
77 		return 0;
78 
79 	if (lock->ml.type == LKM_EXMODE)
80 		/* EX blocks anything left, any bast still valid */
81 		return 0;
82 	else if (lock->ml.type == LKM_NLMODE)
83 		/* NL blocks nothing, no reason to send any bast, cancel it */
84 		return 1;
85 	else if (lock->ml.highest_blocked != LKM_EXMODE)
86 		/* PR only blocks EX */
87 		return 1;
88 
89 	return 0;
90 }
91 
92 static void __dlm_queue_ast(struct dlm_ctxt *dlm, struct dlm_lock *lock)
93 {
94 	mlog_entry_void();
95 
96 	BUG_ON(!dlm);
97 	BUG_ON(!lock);
98 
99 	assert_spin_locked(&dlm->ast_lock);
100 	if (!list_empty(&lock->ast_list)) {
101 		mlog(ML_ERROR, "ast list not empty!!  pending=%d, newlevel=%d\n",
102 		     lock->ast_pending, lock->ml.type);
103 		BUG();
104 	}
105 	if (lock->ast_pending)
106 		mlog(0, "lock has an ast getting flushed right now\n");
107 
108 	/* putting lock on list, add a ref */
109 	dlm_lock_get(lock);
110 	spin_lock(&lock->spinlock);
111 
112 	/* check to see if this ast obsoletes the bast */
113 	if (dlm_should_cancel_bast(dlm, lock)) {
114 		struct dlm_lock_resource *res = lock->lockres;
115 		mlog(0, "%s: cancelling bast for %.*s\n",
116 		     dlm->name, res->lockname.len, res->lockname.name);
117 		lock->bast_pending = 0;
118 		list_del_init(&lock->bast_list);
119 		lock->ml.highest_blocked = LKM_IVMODE;
120 		/* removing lock from list, remove a ref.  guaranteed
121 		 * this won't be the last ref because of the get above,
122 		 * so res->spinlock will not be taken here */
123 		dlm_lock_put(lock);
124 		/* free up the reserved bast that we are cancelling.
125 		 * guaranteed that this will not be the last reserved
126 		 * ast because *both* an ast and a bast were reserved
127 		 * to get to this point.  the res->spinlock will not be
128 		 * taken here */
129 		dlm_lockres_release_ast(dlm, res);
130 	}
131 	list_add_tail(&lock->ast_list, &dlm->pending_asts);
132 	lock->ast_pending = 1;
133 	spin_unlock(&lock->spinlock);
134 }
135 
136 void dlm_queue_ast(struct dlm_ctxt *dlm, struct dlm_lock *lock)
137 {
138 	mlog_entry_void();
139 
140 	BUG_ON(!dlm);
141 	BUG_ON(!lock);
142 
143 	spin_lock(&dlm->ast_lock);
144 	__dlm_queue_ast(dlm, lock);
145 	spin_unlock(&dlm->ast_lock);
146 }
147 
148 
149 static void __dlm_queue_bast(struct dlm_ctxt *dlm, struct dlm_lock *lock)
150 {
151 	mlog_entry_void();
152 
153 	BUG_ON(!dlm);
154 	BUG_ON(!lock);
155 	assert_spin_locked(&dlm->ast_lock);
156 
157 	BUG_ON(!list_empty(&lock->bast_list));
158 	if (lock->bast_pending)
159 		mlog(0, "lock has a bast getting flushed right now\n");
160 
161 	/* putting lock on list, add a ref */
162 	dlm_lock_get(lock);
163 	spin_lock(&lock->spinlock);
164 	list_add_tail(&lock->bast_list, &dlm->pending_basts);
165 	lock->bast_pending = 1;
166 	spin_unlock(&lock->spinlock);
167 }
168 
169 void dlm_queue_bast(struct dlm_ctxt *dlm, struct dlm_lock *lock)
170 {
171 	mlog_entry_void();
172 
173 	BUG_ON(!dlm);
174 	BUG_ON(!lock);
175 
176 	spin_lock(&dlm->ast_lock);
177 	__dlm_queue_bast(dlm, lock);
178 	spin_unlock(&dlm->ast_lock);
179 }
180 
181 static void dlm_update_lvb(struct dlm_ctxt *dlm, struct dlm_lock_resource *res,
182 			   struct dlm_lock *lock)
183 {
184 	struct dlm_lockstatus *lksb = lock->lksb;
185 	BUG_ON(!lksb);
186 
187 	/* only updates if this node masters the lockres */
188 	if (res->owner == dlm->node_num) {
189 
190 		spin_lock(&res->spinlock);
191 		/* check the lksb flags for the direction */
192 		if (lksb->flags & DLM_LKSB_GET_LVB) {
193 			mlog(0, "getting lvb from lockres for %s node\n",
194 				  lock->ml.node == dlm->node_num ? "master" :
195 				  "remote");
196 			memcpy(lksb->lvb, res->lvb, DLM_LVB_LEN);
197 		}
198 		/* Do nothing for lvb put requests - they should be done in
199  		 * place when the lock is downconverted - otherwise we risk
200  		 * racing gets and puts which could result in old lvb data
201  		 * being propagated. We leave the put flag set and clear it
202  		 * here. In the future we might want to clear it at the time
203  		 * the put is actually done.
204 		 */
205 		spin_unlock(&res->spinlock);
206 	}
207 
208 	/* reset any lvb flags on the lksb */
209 	lksb->flags &= ~(DLM_LKSB_PUT_LVB|DLM_LKSB_GET_LVB);
210 }
211 
212 void dlm_do_local_ast(struct dlm_ctxt *dlm, struct dlm_lock_resource *res,
213 		      struct dlm_lock *lock)
214 {
215 	dlm_astlockfunc_t *fn;
216 	struct dlm_lockstatus *lksb;
217 
218 	mlog_entry_void();
219 
220 	lksb = lock->lksb;
221 	fn = lock->ast;
222 	BUG_ON(lock->ml.node != dlm->node_num);
223 
224 	dlm_update_lvb(dlm, res, lock);
225 	(*fn)(lock->astdata);
226 }
227 
228 
229 int dlm_do_remote_ast(struct dlm_ctxt *dlm, struct dlm_lock_resource *res,
230 		      struct dlm_lock *lock)
231 {
232 	int ret;
233 	struct dlm_lockstatus *lksb;
234 	int lksbflags;
235 
236 	mlog_entry_void();
237 
238 	lksb = lock->lksb;
239 	BUG_ON(lock->ml.node == dlm->node_num);
240 
241 	lksbflags = lksb->flags;
242 	dlm_update_lvb(dlm, res, lock);
243 
244 	/* lock request came from another node
245 	 * go do the ast over there */
246 	ret = dlm_send_proxy_ast(dlm, res, lock, lksbflags);
247 	return ret;
248 }
249 
250 void dlm_do_local_bast(struct dlm_ctxt *dlm, struct dlm_lock_resource *res,
251 		       struct dlm_lock *lock, int blocked_type)
252 {
253 	dlm_bastlockfunc_t *fn = lock->bast;
254 
255 	mlog_entry_void();
256 	BUG_ON(lock->ml.node != dlm->node_num);
257 
258 	(*fn)(lock->astdata, blocked_type);
259 }
260 
261 
262 
263 int dlm_proxy_ast_handler(struct o2net_msg *msg, u32 len, void *data,
264 			  void **ret_data)
265 {
266 	int ret;
267 	unsigned int locklen;
268 	struct dlm_ctxt *dlm = data;
269 	struct dlm_lock_resource *res = NULL;
270 	struct dlm_lock *lock = NULL;
271 	struct dlm_proxy_ast *past = (struct dlm_proxy_ast *) msg->buf;
272 	char *name;
273 	struct list_head *iter, *head=NULL;
274 	u64 cookie;
275 	u32 flags;
276 	u8 node;
277 
278 	if (!dlm_grab(dlm)) {
279 		dlm_error(DLM_REJECTED);
280 		return DLM_REJECTED;
281 	}
282 
283 	mlog_bug_on_msg(!dlm_domain_fully_joined(dlm),
284 			"Domain %s not fully joined!\n", dlm->name);
285 
286 	name = past->name;
287 	locklen = past->namelen;
288 	cookie = past->cookie;
289 	flags = be32_to_cpu(past->flags);
290 	node = past->node_idx;
291 
292 	if (locklen > DLM_LOCKID_NAME_MAX) {
293 		ret = DLM_IVBUFLEN;
294 		mlog(ML_ERROR, "Invalid name length (%d) in proxy ast "
295 		     "handler!\n", locklen);
296 		goto leave;
297 	}
298 
299 	if ((flags & (LKM_PUT_LVB|LKM_GET_LVB)) ==
300 	     (LKM_PUT_LVB|LKM_GET_LVB)) {
301 		mlog(ML_ERROR, "Both PUT and GET lvb specified, (0x%x)\n",
302 		     flags);
303 		ret = DLM_BADARGS;
304 		goto leave;
305 	}
306 
307 	mlog(0, "lvb: %s\n", flags & LKM_PUT_LVB ? "put lvb" :
308 		  (flags & LKM_GET_LVB ? "get lvb" : "none"));
309 
310 	mlog(0, "type=%d, blocked_type=%d\n", past->type, past->blocked_type);
311 
312 	if (past->type != DLM_AST &&
313 	    past->type != DLM_BAST) {
314 		mlog(ML_ERROR, "Unknown ast type! %d, cookie=%u:%llu"
315 		     "name=%.*s, node=%u\n", past->type,
316 		     dlm_get_lock_cookie_node(be64_to_cpu(cookie)),
317 		     dlm_get_lock_cookie_seq(be64_to_cpu(cookie)),
318 		     locklen, name, node);
319 		ret = DLM_IVLOCKID;
320 		goto leave;
321 	}
322 
323 	res = dlm_lookup_lockres(dlm, name, locklen);
324 	if (!res) {
325 		mlog(0, "Got %sast for unknown lockres! cookie=%u:%llu, "
326 		     "name=%.*s, node=%u\n", (past->type == DLM_AST ? "" : "b"),
327 		     dlm_get_lock_cookie_node(be64_to_cpu(cookie)),
328 		     dlm_get_lock_cookie_seq(be64_to_cpu(cookie)),
329 		     locklen, name, node);
330 		ret = DLM_IVLOCKID;
331 		goto leave;
332 	}
333 
334 	/* cannot get a proxy ast message if this node owns it */
335 	BUG_ON(res->owner == dlm->node_num);
336 
337 	mlog(0, "lockres %.*s\n", res->lockname.len, res->lockname.name);
338 
339 	spin_lock(&res->spinlock);
340 	if (res->state & DLM_LOCK_RES_RECOVERING) {
341 		mlog(0, "Responding with DLM_RECOVERING!\n");
342 		ret = DLM_RECOVERING;
343 		goto unlock_out;
344 	}
345 	if (res->state & DLM_LOCK_RES_MIGRATING) {
346 		mlog(0, "Responding with DLM_MIGRATING!\n");
347 		ret = DLM_MIGRATING;
348 		goto unlock_out;
349 	}
350 	/* try convert queue for both ast/bast */
351 	head = &res->converting;
352 	lock = NULL;
353 	list_for_each(iter, head) {
354 		lock = list_entry (iter, struct dlm_lock, list);
355 		if (lock->ml.cookie == cookie)
356 			goto do_ast;
357 	}
358 
359 	/* if not on convert, try blocked for ast, granted for bast */
360 	if (past->type == DLM_AST)
361 		head = &res->blocked;
362 	else
363 		head = &res->granted;
364 
365 	list_for_each(iter, head) {
366 		lock = list_entry (iter, struct dlm_lock, list);
367 		if (lock->ml.cookie == cookie)
368 			goto do_ast;
369 	}
370 
371 	mlog(0, "Got %sast for unknown lock! cookie=%u:%llu, name=%.*s, "
372 	     "node=%u\n", past->type == DLM_AST ? "" : "b",
373 	     dlm_get_lock_cookie_node(be64_to_cpu(cookie)),
374 	     dlm_get_lock_cookie_seq(be64_to_cpu(cookie)),
375 	     locklen, name, node);
376 
377 	ret = DLM_NORMAL;
378 unlock_out:
379 	spin_unlock(&res->spinlock);
380 	goto leave;
381 
382 do_ast:
383 	ret = DLM_NORMAL;
384 	if (past->type == DLM_AST) {
385 		/* do not alter lock refcount.  switching lists. */
386 		list_move_tail(&lock->list, &res->granted);
387 		mlog(0, "ast: Adding to granted list... type=%d, "
388 		     "convert_type=%d\n", lock->ml.type, lock->ml.convert_type);
389 		if (lock->ml.convert_type != LKM_IVMODE) {
390 			lock->ml.type = lock->ml.convert_type;
391 			lock->ml.convert_type = LKM_IVMODE;
392 		} else {
393 			// should already be there....
394 		}
395 
396 		lock->lksb->status = DLM_NORMAL;
397 
398 		/* if we requested the lvb, fetch it into our lksb now */
399 		if (flags & LKM_GET_LVB) {
400 			BUG_ON(!(lock->lksb->flags & DLM_LKSB_GET_LVB));
401 			memcpy(lock->lksb->lvb, past->lvb, DLM_LVB_LEN);
402 		}
403 	}
404 	spin_unlock(&res->spinlock);
405 
406 	if (past->type == DLM_AST)
407 		dlm_do_local_ast(dlm, res, lock);
408 	else
409 		dlm_do_local_bast(dlm, res, lock, past->blocked_type);
410 
411 leave:
412 	if (res)
413 		dlm_lockres_put(res);
414 
415 	dlm_put(dlm);
416 	return ret;
417 }
418 
419 
420 
421 int dlm_send_proxy_ast_msg(struct dlm_ctxt *dlm, struct dlm_lock_resource *res,
422 			   struct dlm_lock *lock, int msg_type,
423 			   int blocked_type, int flags)
424 {
425 	int ret = 0;
426 	struct dlm_proxy_ast past;
427 	struct kvec vec[2];
428 	size_t veclen = 1;
429 	int status;
430 
431 	mlog_entry("res %.*s, to=%u, type=%d, blocked_type=%d\n",
432 		   res->lockname.len, res->lockname.name, lock->ml.node,
433 		   msg_type, blocked_type);
434 
435 	memset(&past, 0, sizeof(struct dlm_proxy_ast));
436 	past.node_idx = dlm->node_num;
437 	past.type = msg_type;
438 	past.blocked_type = blocked_type;
439 	past.namelen = res->lockname.len;
440 	memcpy(past.name, res->lockname.name, past.namelen);
441 	past.cookie = lock->ml.cookie;
442 
443 	vec[0].iov_len = sizeof(struct dlm_proxy_ast);
444 	vec[0].iov_base = &past;
445 	if (flags & DLM_LKSB_GET_LVB) {
446 		mlog(0, "returning requested LVB data\n");
447 		be32_add_cpu(&past.flags, LKM_GET_LVB);
448 		vec[1].iov_len = DLM_LVB_LEN;
449 		vec[1].iov_base = lock->lksb->lvb;
450 		veclen++;
451 	}
452 
453 	ret = o2net_send_message_vec(DLM_PROXY_AST_MSG, dlm->key, vec, veclen,
454 				     lock->ml.node, &status);
455 	if (ret < 0)
456 		mlog_errno(ret);
457 	else {
458 		if (status == DLM_RECOVERING) {
459 			mlog(ML_ERROR, "sent AST to node %u, it thinks this "
460 			     "node is dead!\n", lock->ml.node);
461 			BUG();
462 		} else if (status == DLM_MIGRATING) {
463 			mlog(ML_ERROR, "sent AST to node %u, it returned "
464 			     "DLM_MIGRATING!\n", lock->ml.node);
465 			BUG();
466 		} else if (status != DLM_NORMAL && status != DLM_IVLOCKID) {
467 			mlog(ML_ERROR, "AST to node %u returned %d!\n",
468 			     lock->ml.node, status);
469 			/* ignore it */
470 		}
471 		ret = 0;
472 	}
473 	return ret;
474 }
475