1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * dlmast.c
4  *
5  * AST and BAST functionality for local and remote nodes
6  *
7  * Copyright (C) 2004 Oracle.  All rights reserved.
8  */
9 
10 
11 #include <linux/module.h>
12 #include <linux/fs.h>
13 #include <linux/types.h>
14 #include <linux/highmem.h>
15 #include <linux/init.h>
16 #include <linux/sysctl.h>
17 #include <linux/random.h>
18 #include <linux/blkdev.h>
19 #include <linux/socket.h>
20 #include <linux/inet.h>
21 #include <linux/spinlock.h>
22 
23 
24 #include "../cluster/heartbeat.h"
25 #include "../cluster/nodemanager.h"
26 #include "../cluster/tcp.h"
27 
28 #include "dlmapi.h"
29 #include "dlmcommon.h"
30 
31 #define MLOG_MASK_PREFIX ML_DLM
32 #include "../cluster/masklog.h"
33 
34 static void dlm_update_lvb(struct dlm_ctxt *dlm, struct dlm_lock_resource *res,
35 			   struct dlm_lock *lock);
36 static int dlm_should_cancel_bast(struct dlm_ctxt *dlm, struct dlm_lock *lock);
37 
38 /* Should be called as an ast gets queued to see if the new
39  * lock level will obsolete a pending bast.
40  * For example, if dlm_thread queued a bast for an EX lock that
41  * was blocking another EX, but before sending the bast the
42  * lock owner downconverted to NL, the bast is now obsolete.
43  * Only the ast should be sent.
44  * This is needed because the lock and convert paths can queue
45  * asts out-of-band (not waiting for dlm_thread) in order to
46  * allow for LKM_NOQUEUE to get immediate responses. */
dlm_should_cancel_bast(struct dlm_ctxt * dlm,struct dlm_lock * lock)47 static int dlm_should_cancel_bast(struct dlm_ctxt *dlm, struct dlm_lock *lock)
48 {
49 	assert_spin_locked(&dlm->ast_lock);
50 	assert_spin_locked(&lock->spinlock);
51 
52 	if (lock->ml.highest_blocked == LKM_IVMODE)
53 		return 0;
54 	BUG_ON(lock->ml.highest_blocked == LKM_NLMODE);
55 
56 	if (lock->bast_pending &&
57 	    list_empty(&lock->bast_list))
58 		/* old bast already sent, ok */
59 		return 0;
60 
61 	if (lock->ml.type == LKM_EXMODE)
62 		/* EX blocks anything left, any bast still valid */
63 		return 0;
64 	else if (lock->ml.type == LKM_NLMODE)
65 		/* NL blocks nothing, no reason to send any bast, cancel it */
66 		return 1;
67 	else if (lock->ml.highest_blocked != LKM_EXMODE)
68 		/* PR only blocks EX */
69 		return 1;
70 
71 	return 0;
72 }
73 
__dlm_queue_ast(struct dlm_ctxt * dlm,struct dlm_lock * lock)74 void __dlm_queue_ast(struct dlm_ctxt *dlm, struct dlm_lock *lock)
75 {
76 	struct dlm_lock_resource *res;
77 
78 	BUG_ON(!dlm);
79 	BUG_ON(!lock);
80 
81 	res = lock->lockres;
82 
83 	assert_spin_locked(&dlm->ast_lock);
84 
85 	if (!list_empty(&lock->ast_list)) {
86 		mlog(ML_ERROR, "%s: res %.*s, lock %u:%llu, "
87 		     "AST list not empty, pending %d, newlevel %d\n",
88 		     dlm->name, res->lockname.len, res->lockname.name,
89 		     dlm_get_lock_cookie_node(be64_to_cpu(lock->ml.cookie)),
90 		     dlm_get_lock_cookie_seq(be64_to_cpu(lock->ml.cookie)),
91 		     lock->ast_pending, lock->ml.type);
92 		BUG();
93 	}
94 	if (lock->ast_pending)
95 		mlog(0, "%s: res %.*s, lock %u:%llu, AST getting flushed\n",
96 		     dlm->name, res->lockname.len, res->lockname.name,
97 		     dlm_get_lock_cookie_node(be64_to_cpu(lock->ml.cookie)),
98 		     dlm_get_lock_cookie_seq(be64_to_cpu(lock->ml.cookie)));
99 
100 	/* putting lock on list, add a ref */
101 	dlm_lock_get(lock);
102 	spin_lock(&lock->spinlock);
103 
104 	/* check to see if this ast obsoletes the bast */
105 	if (dlm_should_cancel_bast(dlm, lock)) {
106 		mlog(0, "%s: res %.*s, lock %u:%llu, Cancelling BAST\n",
107 		     dlm->name, res->lockname.len, res->lockname.name,
108 		     dlm_get_lock_cookie_node(be64_to_cpu(lock->ml.cookie)),
109 		     dlm_get_lock_cookie_seq(be64_to_cpu(lock->ml.cookie)));
110 		lock->bast_pending = 0;
111 		list_del_init(&lock->bast_list);
112 		lock->ml.highest_blocked = LKM_IVMODE;
113 		/* removing lock from list, remove a ref.  guaranteed
114 		 * this won't be the last ref because of the get above,
115 		 * so res->spinlock will not be taken here */
116 		dlm_lock_put(lock);
117 		/* free up the reserved bast that we are cancelling.
118 		 * guaranteed that this will not be the last reserved
119 		 * ast because *both* an ast and a bast were reserved
120 		 * to get to this point.  the res->spinlock will not be
121 		 * taken here */
122 		dlm_lockres_release_ast(dlm, res);
123 	}
124 	list_add_tail(&lock->ast_list, &dlm->pending_asts);
125 	lock->ast_pending = 1;
126 	spin_unlock(&lock->spinlock);
127 }
128 
dlm_queue_ast(struct dlm_ctxt * dlm,struct dlm_lock * lock)129 void dlm_queue_ast(struct dlm_ctxt *dlm, struct dlm_lock *lock)
130 {
131 	BUG_ON(!dlm);
132 	BUG_ON(!lock);
133 
134 	spin_lock(&dlm->ast_lock);
135 	__dlm_queue_ast(dlm, lock);
136 	spin_unlock(&dlm->ast_lock);
137 }
138 
139 
__dlm_queue_bast(struct dlm_ctxt * dlm,struct dlm_lock * lock)140 void __dlm_queue_bast(struct dlm_ctxt *dlm, struct dlm_lock *lock)
141 {
142 	struct dlm_lock_resource *res;
143 
144 	BUG_ON(!dlm);
145 	BUG_ON(!lock);
146 
147 	assert_spin_locked(&dlm->ast_lock);
148 
149 	res = lock->lockres;
150 
151 	BUG_ON(!list_empty(&lock->bast_list));
152 	if (lock->bast_pending)
153 		mlog(0, "%s: res %.*s, lock %u:%llu, BAST getting flushed\n",
154 		     dlm->name, res->lockname.len, res->lockname.name,
155 		     dlm_get_lock_cookie_node(be64_to_cpu(lock->ml.cookie)),
156 		     dlm_get_lock_cookie_seq(be64_to_cpu(lock->ml.cookie)));
157 
158 	/* putting lock on list, add a ref */
159 	dlm_lock_get(lock);
160 	spin_lock(&lock->spinlock);
161 	list_add_tail(&lock->bast_list, &dlm->pending_basts);
162 	lock->bast_pending = 1;
163 	spin_unlock(&lock->spinlock);
164 }
165 
dlm_update_lvb(struct dlm_ctxt * dlm,struct dlm_lock_resource * res,struct dlm_lock * lock)166 static void dlm_update_lvb(struct dlm_ctxt *dlm, struct dlm_lock_resource *res,
167 			   struct dlm_lock *lock)
168 {
169 	struct dlm_lockstatus *lksb = lock->lksb;
170 	BUG_ON(!lksb);
171 
172 	/* only updates if this node masters the lockres */
173 	spin_lock(&res->spinlock);
174 	if (res->owner == dlm->node_num) {
175 		/* check the lksb flags for the direction */
176 		if (lksb->flags & DLM_LKSB_GET_LVB) {
177 			mlog(0, "getting lvb from lockres for %s node\n",
178 				  lock->ml.node == dlm->node_num ? "master" :
179 				  "remote");
180 			memcpy(lksb->lvb, res->lvb, DLM_LVB_LEN);
181 		}
182 		/* Do nothing for lvb put requests - they should be done in
183  		 * place when the lock is downconverted - otherwise we risk
184  		 * racing gets and puts which could result in old lvb data
185  		 * being propagated. We leave the put flag set and clear it
186  		 * here. In the future we might want to clear it at the time
187  		 * the put is actually done.
188 		 */
189 	}
190 	spin_unlock(&res->spinlock);
191 
192 	/* reset any lvb flags on the lksb */
193 	lksb->flags &= ~(DLM_LKSB_PUT_LVB|DLM_LKSB_GET_LVB);
194 }
195 
dlm_do_local_ast(struct dlm_ctxt * dlm,struct dlm_lock_resource * res,struct dlm_lock * lock)196 void dlm_do_local_ast(struct dlm_ctxt *dlm, struct dlm_lock_resource *res,
197 		      struct dlm_lock *lock)
198 {
199 	dlm_astlockfunc_t *fn;
200 
201 	mlog(0, "%s: res %.*s, lock %u:%llu, Local AST\n", dlm->name,
202 	     res->lockname.len, res->lockname.name,
203 	     dlm_get_lock_cookie_node(be64_to_cpu(lock->ml.cookie)),
204 	     dlm_get_lock_cookie_seq(be64_to_cpu(lock->ml.cookie)));
205 
206 	fn = lock->ast;
207 	BUG_ON(lock->ml.node != dlm->node_num);
208 
209 	dlm_update_lvb(dlm, res, lock);
210 	(*fn)(lock->astdata);
211 }
212 
213 
dlm_do_remote_ast(struct dlm_ctxt * dlm,struct dlm_lock_resource * res,struct dlm_lock * lock)214 int dlm_do_remote_ast(struct dlm_ctxt *dlm, struct dlm_lock_resource *res,
215 		      struct dlm_lock *lock)
216 {
217 	int ret;
218 	struct dlm_lockstatus *lksb;
219 	int lksbflags;
220 
221 	mlog(0, "%s: res %.*s, lock %u:%llu, Remote AST\n", dlm->name,
222 	     res->lockname.len, res->lockname.name,
223 	     dlm_get_lock_cookie_node(be64_to_cpu(lock->ml.cookie)),
224 	     dlm_get_lock_cookie_seq(be64_to_cpu(lock->ml.cookie)));
225 
226 	lksb = lock->lksb;
227 	BUG_ON(lock->ml.node == dlm->node_num);
228 
229 	lksbflags = lksb->flags;
230 	dlm_update_lvb(dlm, res, lock);
231 
232 	/* lock request came from another node
233 	 * go do the ast over there */
234 	ret = dlm_send_proxy_ast(dlm, res, lock, lksbflags);
235 	return ret;
236 }
237 
dlm_do_local_bast(struct dlm_ctxt * dlm,struct dlm_lock_resource * res,struct dlm_lock * lock,int blocked_type)238 void dlm_do_local_bast(struct dlm_ctxt *dlm, struct dlm_lock_resource *res,
239 		       struct dlm_lock *lock, int blocked_type)
240 {
241 	dlm_bastlockfunc_t *fn = lock->bast;
242 
243 	BUG_ON(lock->ml.node != dlm->node_num);
244 
245 	mlog(0, "%s: res %.*s, lock %u:%llu, Local BAST, blocked %d\n",
246 	     dlm->name, res->lockname.len, res->lockname.name,
247 	     dlm_get_lock_cookie_node(be64_to_cpu(lock->ml.cookie)),
248 	     dlm_get_lock_cookie_seq(be64_to_cpu(lock->ml.cookie)),
249 	     blocked_type);
250 
251 	(*fn)(lock->astdata, blocked_type);
252 }
253 
254 
255 
dlm_proxy_ast_handler(struct o2net_msg * msg,u32 len,void * data,void ** ret_data)256 int dlm_proxy_ast_handler(struct o2net_msg *msg, u32 len, void *data,
257 			  void **ret_data)
258 {
259 	int ret;
260 	unsigned int locklen;
261 	struct dlm_ctxt *dlm = data;
262 	struct dlm_lock_resource *res = NULL;
263 	struct dlm_lock *lock = NULL;
264 	struct dlm_proxy_ast *past = (struct dlm_proxy_ast *) msg->buf;
265 	char *name;
266 	struct list_head *head = NULL;
267 	__be64 cookie;
268 	u32 flags;
269 	u8 node;
270 
271 	if (!dlm_grab(dlm)) {
272 		dlm_error(DLM_REJECTED);
273 		return DLM_REJECTED;
274 	}
275 
276 	mlog_bug_on_msg(!dlm_domain_fully_joined(dlm),
277 			"Domain %s not fully joined!\n", dlm->name);
278 
279 	name = past->name;
280 	locklen = past->namelen;
281 	cookie = past->cookie;
282 	flags = be32_to_cpu(past->flags);
283 	node = past->node_idx;
284 
285 	if (locklen > DLM_LOCKID_NAME_MAX) {
286 		ret = DLM_IVBUFLEN;
287 		mlog(ML_ERROR, "Invalid name length (%d) in proxy ast "
288 		     "handler!\n", locklen);
289 		goto leave;
290 	}
291 
292 	if ((flags & (LKM_PUT_LVB|LKM_GET_LVB)) ==
293 	     (LKM_PUT_LVB|LKM_GET_LVB)) {
294 		mlog(ML_ERROR, "Both PUT and GET lvb specified, (0x%x)\n",
295 		     flags);
296 		ret = DLM_BADARGS;
297 		goto leave;
298 	}
299 
300 	mlog(0, "lvb: %s\n", flags & LKM_PUT_LVB ? "put lvb" :
301 		  (flags & LKM_GET_LVB ? "get lvb" : "none"));
302 
303 	mlog(0, "type=%d, blocked_type=%d\n", past->type, past->blocked_type);
304 
305 	if (past->type != DLM_AST &&
306 	    past->type != DLM_BAST) {
307 		mlog(ML_ERROR, "Unknown ast type! %d, cookie=%u:%llu"
308 		     "name=%.*s, node=%u\n", past->type,
309 		     dlm_get_lock_cookie_node(be64_to_cpu(cookie)),
310 		     dlm_get_lock_cookie_seq(be64_to_cpu(cookie)),
311 		     locklen, name, node);
312 		ret = DLM_IVLOCKID;
313 		goto leave;
314 	}
315 
316 	res = dlm_lookup_lockres(dlm, name, locklen);
317 	if (!res) {
318 		mlog(0, "Got %sast for unknown lockres! cookie=%u:%llu, "
319 		     "name=%.*s, node=%u\n", (past->type == DLM_AST ? "" : "b"),
320 		     dlm_get_lock_cookie_node(be64_to_cpu(cookie)),
321 		     dlm_get_lock_cookie_seq(be64_to_cpu(cookie)),
322 		     locklen, name, node);
323 		ret = DLM_IVLOCKID;
324 		goto leave;
325 	}
326 
327 	/* cannot get a proxy ast message if this node owns it */
328 	BUG_ON(res->owner == dlm->node_num);
329 
330 	mlog(0, "%s: res %.*s\n", dlm->name, res->lockname.len,
331 	     res->lockname.name);
332 
333 	spin_lock(&res->spinlock);
334 	if (res->state & DLM_LOCK_RES_RECOVERING) {
335 		mlog(0, "Responding with DLM_RECOVERING!\n");
336 		ret = DLM_RECOVERING;
337 		goto unlock_out;
338 	}
339 	if (res->state & DLM_LOCK_RES_MIGRATING) {
340 		mlog(0, "Responding with DLM_MIGRATING!\n");
341 		ret = DLM_MIGRATING;
342 		goto unlock_out;
343 	}
344 	/* try convert queue for both ast/bast */
345 	head = &res->converting;
346 	lock = NULL;
347 	list_for_each_entry(lock, head, list) {
348 		if (lock->ml.cookie == cookie)
349 			goto do_ast;
350 	}
351 
352 	/* if not on convert, try blocked for ast, granted for bast */
353 	if (past->type == DLM_AST)
354 		head = &res->blocked;
355 	else
356 		head = &res->granted;
357 
358 	list_for_each_entry(lock, head, list) {
359 		/* if lock is found but unlock is pending ignore the bast */
360 		if (lock->ml.cookie == cookie) {
361 			if (lock->unlock_pending)
362 				break;
363 			goto do_ast;
364 		}
365 	}
366 
367 	mlog(0, "Got %sast for unknown lock! cookie=%u:%llu, name=%.*s, "
368 	     "node=%u\n", past->type == DLM_AST ? "" : "b",
369 	     dlm_get_lock_cookie_node(be64_to_cpu(cookie)),
370 	     dlm_get_lock_cookie_seq(be64_to_cpu(cookie)),
371 	     locklen, name, node);
372 
373 	ret = DLM_NORMAL;
374 unlock_out:
375 	spin_unlock(&res->spinlock);
376 	goto leave;
377 
378 do_ast:
379 	ret = DLM_NORMAL;
380 	if (past->type == DLM_AST) {
381 		/* do not alter lock refcount.  switching lists. */
382 		list_move_tail(&lock->list, &res->granted);
383 		mlog(0, "%s: res %.*s, lock %u:%llu, Granted type %d => %d\n",
384 		     dlm->name, res->lockname.len, res->lockname.name,
385 		     dlm_get_lock_cookie_node(be64_to_cpu(cookie)),
386 		     dlm_get_lock_cookie_seq(be64_to_cpu(cookie)),
387 		     lock->ml.type, lock->ml.convert_type);
388 
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 
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)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(0, "%s: res %.*s, to %u, type %d, blocked_type %d\n", dlm->name,
432 	     res->lockname.len, res->lockname.name, lock->ml.node, msg_type,
433 	     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 		be32_add_cpu(&past.flags, LKM_GET_LVB);
447 		vec[1].iov_len = DLM_LVB_LEN;
448 		vec[1].iov_base = lock->lksb->lvb;
449 		veclen++;
450 	}
451 
452 	ret = o2net_send_message_vec(DLM_PROXY_AST_MSG, dlm->key, vec, veclen,
453 				     lock->ml.node, &status);
454 	if (ret < 0)
455 		mlog(ML_ERROR, "%s: res %.*s, error %d send AST to node %u\n",
456 		     dlm->name, res->lockname.len, res->lockname.name, ret,
457 		     lock->ml.node);
458 	else {
459 		if (status == DLM_RECOVERING) {
460 			mlog(ML_ERROR, "sent AST to node %u, it thinks this "
461 			     "node is dead!\n", lock->ml.node);
462 			BUG();
463 		} else if (status == DLM_MIGRATING) {
464 			mlog(ML_ERROR, "sent AST to node %u, it returned "
465 			     "DLM_MIGRATING!\n", lock->ml.node);
466 			BUG();
467 		} else if (status != DLM_NORMAL && status != DLM_IVLOCKID) {
468 			mlog(ML_ERROR, "AST to node %u returned %d!\n",
469 			     lock->ml.node, status);
470 			/* ignore it */
471 		}
472 		ret = 0;
473 	}
474 	return ret;
475 }
476