xref: /openbmc/linux/fs/ocfs2/dlm/dlmast.c (revision 87c2ce3b) 
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/utsname.h>
34 #include <linux/init.h>
35 #include <linux/sysctl.h>
36 #include <linux/random.h>
37 #include <linux/blkdev.h>
38 #include <linux/socket.h>
39 #include <linux/inet.h>
40 #include <linux/spinlock.h>
41 
42 
43 #include "cluster/heartbeat.h"
44 #include "cluster/nodemanager.h"
45 #include "cluster/tcp.h"
46 #include "cluster/endian.h"
47 
48 #include "dlmapi.h"
49 #include "dlmcommon.h"
50 
51 #define MLOG_MASK_PREFIX ML_DLM
52 #include "cluster/masklog.h"
53 
54 static void dlm_update_lvb(struct dlm_ctxt *dlm, struct dlm_lock_resource *res,
55 			   struct dlm_lock *lock);
56 static int dlm_should_cancel_bast(struct dlm_ctxt *dlm, struct dlm_lock *lock);
57 
58 /* Should be called as an ast gets queued to see if the new
59  * lock level will obsolete a pending bast.
60  * For example, if dlm_thread queued a bast for an EX lock that
61  * was blocking another EX, but before sending the bast the
62  * lock owner downconverted to NL, the bast is now obsolete.
63  * Only the ast should be sent.
64  * This is needed because the lock and convert paths can queue
65  * asts out-of-band (not waiting for dlm_thread) in order to
66  * allow for LKM_NOQUEUE to get immediate responses. */
67 static int dlm_should_cancel_bast(struct dlm_ctxt *dlm, struct dlm_lock *lock)
68 {
69 	assert_spin_locked(&dlm->ast_lock);
70 	assert_spin_locked(&lock->spinlock);
71 
72 	if (lock->ml.highest_blocked == LKM_IVMODE)
73 		return 0;
74 	BUG_ON(lock->ml.highest_blocked == LKM_NLMODE);
75 
76 	if (lock->bast_pending &&
77 	    list_empty(&lock->bast_list))
78 		/* old bast already sent, ok */
79 		return 0;
80 
81 	if (lock->ml.type == LKM_EXMODE)
82 		/* EX blocks anything left, any bast still valid */
83 		return 0;
84 	else if (lock->ml.type == LKM_NLMODE)
85 		/* NL blocks nothing, no reason to send any bast, cancel it */
86 		return 1;
87 	else if (lock->ml.highest_blocked != LKM_EXMODE)
88 		/* PR only blocks EX */
89 		return 1;
90 
91 	return 0;
92 }
93 
94 static void __dlm_queue_ast(struct dlm_ctxt *dlm, struct dlm_lock *lock)
95 {
96 	mlog_entry_void();
97 
98 	BUG_ON(!dlm);
99 	BUG_ON(!lock);
100 
101 	assert_spin_locked(&dlm->ast_lock);
102 	if (!list_empty(&lock->ast_list)) {
103 		mlog(ML_ERROR, "ast list not empty!!  pending=%d, newlevel=%d\n",
104 		     lock->ast_pending, lock->ml.type);
105 		BUG();
106 	}
107 	BUG_ON(!list_empty(&lock->ast_list));
108 	if (lock->ast_pending)
109 		mlog(0, "lock has an ast getting flushed right now\n");
110 
111 	/* putting lock on list, add a ref */
112 	dlm_lock_get(lock);
113 	spin_lock(&lock->spinlock);
114 
115 	/* check to see if this ast obsoletes the bast */
116 	if (dlm_should_cancel_bast(dlm, lock)) {
117 		struct dlm_lock_resource *res = lock->lockres;
118 		mlog(0, "%s: cancelling bast for %.*s\n",
119 		     dlm->name, res->lockname.len, res->lockname.name);
120 		lock->bast_pending = 0;
121 		list_del_init(&lock->bast_list);
122 		lock->ml.highest_blocked = LKM_IVMODE;
123 		/* removing lock from list, remove a ref.  guaranteed
124 		 * this won't be the last ref because of the get above,
125 		 * so res->spinlock will not be taken here */
126 		dlm_lock_put(lock);
127 		/* free up the reserved bast that we are cancelling.
128 		 * guaranteed that this will not be the last reserved
129 		 * ast because *both* an ast and a bast were reserved
130 		 * to get to this point.  the res->spinlock will not be
131 		 * taken here */
132 		dlm_lockres_release_ast(dlm, res);
133 	}
134 	list_add_tail(&lock->ast_list, &dlm->pending_asts);
135 	lock->ast_pending = 1;
136 	spin_unlock(&lock->spinlock);
137 }
138 
139 void dlm_queue_ast(struct dlm_ctxt *dlm, struct dlm_lock *lock)
140 {
141 	mlog_entry_void();
142 
143 	BUG_ON(!dlm);
144 	BUG_ON(!lock);
145 
146 	spin_lock(&dlm->ast_lock);
147 	__dlm_queue_ast(dlm, lock);
148 	spin_unlock(&dlm->ast_lock);
149 }
150 
151 
152 static void __dlm_queue_bast(struct dlm_ctxt *dlm, struct dlm_lock *lock)
153 {
154 	mlog_entry_void();
155 
156 	BUG_ON(!dlm);
157 	BUG_ON(!lock);
158 	assert_spin_locked(&dlm->ast_lock);
159 
160 	BUG_ON(!list_empty(&lock->bast_list));
161 	if (lock->bast_pending)
162 		mlog(0, "lock has a bast getting flushed right now\n");
163 
164 	/* putting lock on list, add a ref */
165 	dlm_lock_get(lock);
166 	spin_lock(&lock->spinlock);
167 	list_add_tail(&lock->bast_list, &dlm->pending_basts);
168 	lock->bast_pending = 1;
169 	spin_unlock(&lock->spinlock);
170 }
171 
172 void dlm_queue_bast(struct dlm_ctxt *dlm, struct dlm_lock *lock)
173 {
174 	mlog_entry_void();
175 
176 	BUG_ON(!dlm);
177 	BUG_ON(!lock);
178 
179 	spin_lock(&dlm->ast_lock);
180 	__dlm_queue_bast(dlm, lock);
181 	spin_unlock(&dlm->ast_lock);
182 }
183 
184 static void dlm_update_lvb(struct dlm_ctxt *dlm, struct dlm_lock_resource *res,
185 			   struct dlm_lock *lock)
186 {
187 	struct dlm_lockstatus *lksb = lock->lksb;
188 	BUG_ON(!lksb);
189 
190 	/* only updates if this node masters the lockres */
191 	if (res->owner == dlm->node_num) {
192 
193 		spin_lock(&res->spinlock);
194 		/* check the lksb flags for the direction */
195 		if (lksb->flags & DLM_LKSB_GET_LVB) {
196 			mlog(0, "getting lvb from lockres for %s node\n",
197 				  lock->ml.node == dlm->node_num ? "master" :
198 				  "remote");
199 			memcpy(lksb->lvb, res->lvb, DLM_LVB_LEN);
200 		} else if (lksb->flags & DLM_LKSB_PUT_LVB) {
201 			mlog(0, "setting lvb from lockres for %s node\n",
202 				  lock->ml.node == dlm->node_num ? "master" :
203 				  "remote");
204 			memcpy(res->lvb, lksb->lvb, DLM_LVB_LEN);
205 		}
206 		spin_unlock(&res->spinlock);
207 	}
208 
209 	/* reset any lvb flags on the lksb */
210 	lksb->flags &= ~(DLM_LKSB_PUT_LVB|DLM_LKSB_GET_LVB);
211 }
212 
213 void dlm_do_local_ast(struct dlm_ctxt *dlm, struct dlm_lock_resource *res,
214 		      struct dlm_lock *lock)
215 {
216 	dlm_astlockfunc_t *fn;
217 	struct dlm_lockstatus *lksb;
218 
219 	mlog_entry_void();
220 
221 	lksb = lock->lksb;
222 	fn = lock->ast;
223 	BUG_ON(lock->ml.node != dlm->node_num);
224 
225 	dlm_update_lvb(dlm, res, lock);
226 	(*fn)(lock->astdata);
227 }
228 
229 
230 int dlm_do_remote_ast(struct dlm_ctxt *dlm, struct dlm_lock_resource *res,
231 		      struct dlm_lock *lock)
232 {
233 	int ret;
234 	struct dlm_lockstatus *lksb;
235 	int lksbflags;
236 
237 	mlog_entry_void();
238 
239 	lksb = lock->lksb;
240 	BUG_ON(lock->ml.node == dlm->node_num);
241 
242 	lksbflags = lksb->flags;
243 	dlm_update_lvb(dlm, res, lock);
244 
245 	/* lock request came from another node
246 	 * go do the ast over there */
247 	ret = dlm_send_proxy_ast(dlm, res, lock, lksbflags);
248 	return ret;
249 }
250 
251 void dlm_do_local_bast(struct dlm_ctxt *dlm, struct dlm_lock_resource *res,
252 		       struct dlm_lock *lock, int blocked_type)
253 {
254 	dlm_bastlockfunc_t *fn = lock->bast;
255 
256 	mlog_entry_void();
257 	BUG_ON(lock->ml.node != dlm->node_num);
258 
259 	(*fn)(lock->astdata, blocked_type);
260 }
261 
262 
263 
264 int dlm_proxy_ast_handler(struct o2net_msg *msg, u32 len, void *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 
277 	if (!dlm_grab(dlm)) {
278 		dlm_error(DLM_REJECTED);
279 		return DLM_REJECTED;
280 	}
281 
282 	mlog_bug_on_msg(!dlm_domain_fully_joined(dlm),
283 			"Domain %s not fully joined!\n", dlm->name);
284 
285 	name = past->name;
286 	locklen = past->namelen;
287 	cookie = be64_to_cpu(past->cookie);
288 	flags = be32_to_cpu(past->flags);
289 
290 	if (locklen > DLM_LOCKID_NAME_MAX) {
291 		ret = DLM_IVBUFLEN;
292 		mlog(ML_ERROR, "Invalid name length in proxy ast handler!\n");
293 		goto leave;
294 	}
295 
296 	if ((flags & (LKM_PUT_LVB|LKM_GET_LVB)) ==
297 	     (LKM_PUT_LVB|LKM_GET_LVB)) {
298 		mlog(ML_ERROR, "both PUT and GET lvb specified\n");
299 		ret = DLM_BADARGS;
300 		goto leave;
301 	}
302 
303 	mlog(0, "lvb: %s\n", flags & LKM_PUT_LVB ? "put lvb" :
304 		  (flags & LKM_GET_LVB ? "get lvb" : "none"));
305 
306 	mlog(0, "type=%d, blocked_type=%d\n", past->type, past->blocked_type);
307 
308 	if (past->type != DLM_AST &&
309 	    past->type != DLM_BAST) {
310 		mlog(ML_ERROR, "Unknown ast type! %d, cookie=%"MLFu64", "
311 		     "name=%.*s\n", past->type, cookie, locklen, name);
312 		ret = DLM_IVLOCKID;
313 		goto leave;
314 	}
315 
316 	res = dlm_lookup_lockres(dlm, name, locklen);
317 	if (!res) {
318 		mlog(ML_ERROR, "got %sast for unknown lockres! "
319 			       "cookie=%"MLFu64", name=%.*s, namelen=%u\n",
320 		     past->type == DLM_AST ? "" : "b",
321 		     cookie, locklen, name, locklen);
322 		ret = DLM_IVLOCKID;
323 		goto leave;
324 	}
325 
326 	/* cannot get a proxy ast message if this node owns it */
327 	BUG_ON(res->owner == dlm->node_num);
328 
329 	mlog(0, "lockres %.*s\n", res->lockname.len, res->lockname.name);
330 
331 	spin_lock(&res->spinlock);
332 	if (res->state & DLM_LOCK_RES_RECOVERING) {
333 		mlog(0, "responding with DLM_RECOVERING!\n");
334 		ret = DLM_RECOVERING;
335 		goto unlock_out;
336 	}
337 	if (res->state & DLM_LOCK_RES_MIGRATING) {
338 		mlog(0, "responding with DLM_MIGRATING!\n");
339 		ret = DLM_MIGRATING;
340 		goto unlock_out;
341 	}
342 	/* try convert queue for both ast/bast */
343 	head = &res->converting;
344 	lock = NULL;
345 	list_for_each(iter, head) {
346 		lock = list_entry (iter, struct dlm_lock, list);
347 		if (be64_to_cpu(lock->ml.cookie) == cookie)
348 			goto do_ast;
349 	}
350 
351 	/* if not on convert, try blocked for ast, granted for bast */
352 	if (past->type == DLM_AST)
353 		head = &res->blocked;
354 	else
355 		head = &res->granted;
356 
357 	list_for_each(iter, head) {
358 		lock = list_entry (iter, struct dlm_lock, list);
359 		if (be64_to_cpu(lock->ml.cookie) == cookie)
360 			goto do_ast;
361 	}
362 
363 	mlog(ML_ERROR, "got %sast for unknown lock!  cookie=%"MLFu64", "
364 		       "name=%.*s, namelen=%u\n",
365              past->type == DLM_AST ? "" : "b", cookie, locklen, name, locklen);
366 
367 	ret = DLM_NORMAL;
368 unlock_out:
369 	spin_unlock(&res->spinlock);
370 	goto leave;
371 
372 do_ast:
373 	ret = DLM_NORMAL;
374 	if (past->type == DLM_AST) {
375 		/* do not alter lock refcount.  switching lists. */
376 		list_del_init(&lock->list);
377 		list_add_tail(&lock->list, &res->granted);
378 		mlog(0, "ast: adding to granted list... type=%d, "
379 			  "convert_type=%d\n", lock->ml.type, lock->ml.convert_type);
380 		if (lock->ml.convert_type != LKM_IVMODE) {
381 			lock->ml.type = lock->ml.convert_type;
382 			lock->ml.convert_type = LKM_IVMODE;
383 		} else {
384 			// should already be there....
385 		}
386 
387 		lock->lksb->status = DLM_NORMAL;
388 
389 		/* if we requested the lvb, fetch it into our lksb now */
390 		if (flags & LKM_GET_LVB) {
391 			BUG_ON(!(lock->lksb->flags & DLM_LKSB_GET_LVB));
392 			memcpy(lock->lksb->lvb, past->lvb, DLM_LVB_LEN);
393 		}
394 	}
395 	spin_unlock(&res->spinlock);
396 
397 	if (past->type == DLM_AST)
398 		dlm_do_local_ast(dlm, res, lock);
399 	else
400 		dlm_do_local_bast(dlm, res, lock, past->blocked_type);
401 
402 leave:
403 
404 	if (res)
405 		dlm_lockres_put(res);
406 
407 	dlm_put(dlm);
408 	return ret;
409 }
410 
411 
412 
413 int dlm_send_proxy_ast_msg(struct dlm_ctxt *dlm, struct dlm_lock_resource *res,
414 			   struct dlm_lock *lock, int msg_type,
415 			   int blocked_type, int flags)
416 {
417 	int ret = 0;
418 	struct dlm_proxy_ast past;
419 	struct kvec vec[2];
420 	size_t veclen = 1;
421 	int status;
422 
423 	mlog_entry("res %.*s, to=%u, type=%d, blocked_type=%d\n",
424 		   res->lockname.len, res->lockname.name, lock->ml.node,
425 		   msg_type, blocked_type);
426 
427 	memset(&past, 0, sizeof(struct dlm_proxy_ast));
428 	past.node_idx = dlm->node_num;
429 	past.type = msg_type;
430 	past.blocked_type = blocked_type;
431 	past.namelen = res->lockname.len;
432 	memcpy(past.name, res->lockname.name, past.namelen);
433 	past.cookie = lock->ml.cookie;
434 
435 	vec[0].iov_len = sizeof(struct dlm_proxy_ast);
436 	vec[0].iov_base = &past;
437 	if (flags & DLM_LKSB_GET_LVB) {
438 		mlog(0, "returning requested LVB data\n");
439 		be32_add_cpu(&past.flags, LKM_GET_LVB);
440 		vec[1].iov_len = DLM_LVB_LEN;
441 		vec[1].iov_base = lock->lksb->lvb;
442 		veclen++;
443 	}
444 
445 	ret = o2net_send_message_vec(DLM_PROXY_AST_MSG, dlm->key, vec, veclen,
446 				     lock->ml.node, &status);
447 	if (ret < 0)
448 		mlog_errno(ret);
449 	else {
450 		if (status == DLM_RECOVERING) {
451 			mlog(ML_ERROR, "sent AST to node %u, it thinks this "
452 			     "node is dead!\n", lock->ml.node);
453 			BUG();
454 		} else if (status == DLM_MIGRATING) {
455 			mlog(ML_ERROR, "sent AST to node %u, it returned "
456 			     "DLM_MIGRATING!\n", lock->ml.node);
457 			BUG();
458 		} else if (status != DLM_NORMAL) {
459 			mlog(ML_ERROR, "AST to node %u returned %d!\n",
460 			     lock->ml.node, status);
461 			/* ignore it */
462 		}
463 		ret = 0;
464 	}
465 	return ret;
466 }
467