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
34static void dlm_update_lvb(struct dlm_ctxt *dlm, struct dlm_lock_resource *res,
35			   struct dlm_lock *lock);
36static 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. */
47static 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
74void __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
129void 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
140void __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
166static 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
196void 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
214int 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
238void 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
256int 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;
374unlock_out:
375	spin_unlock(&res->spinlock);
376	goto leave;
377
378do_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
411leave:
412	if (res)
413		dlm_lockres_put(res);
414
415	dlm_put(dlm);
416	return ret;
417}
418
419
420
421int 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