summaryrefslogtreecommitdiffstats
path: root/fs/gfs2/locking/dlm/thread.c
blob: e53db6fd28ab62f140e44557c993d24f1036d1c1 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
/*
 * Copyright (C) Sistina Software, Inc.  1997-2003 All rights reserved.
 * Copyright (C) 2004-2005 Red Hat, Inc.  All rights reserved.
 *
 * This copyrighted material is made available to anyone wishing to use,
 * modify, copy, or redistribute it subject to the terms and conditions
 * of the GNU General Public License version 2.
 */

#include "lock_dlm.h"

/* A lock placed on this queue is re-submitted to DLM as soon as the lock_dlm
   thread gets to it. */

static void queue_submit(struct gdlm_lock *lp)
{
	struct gdlm_ls *ls = lp->ls;

	spin_lock(&ls->async_lock);
	list_add_tail(&lp->delay_list, &ls->submit);
	spin_unlock(&ls->async_lock);
	wake_up(&ls->thread_wait);
}

static void process_blocking(struct gdlm_lock *lp, int bast_mode)
{
	struct gdlm_ls *ls = lp->ls;
	unsigned int cb = 0;

	switch (gdlm_make_lmstate(bast_mode)) {
	case LM_ST_EXCLUSIVE:
		cb = LM_CB_NEED_E;
		break;
	case LM_ST_DEFERRED:
		cb = LM_CB_NEED_D;
		break;
	case LM_ST_SHARED:
		cb = LM_CB_NEED_S;
		break;
	default:
		gdlm_assert(0, "unknown bast mode %u", lp->bast_mode);
	}

	ls->fscb(ls->sdp, cb, &lp->lockname);
}

static void wake_up_ast(struct gdlm_lock *lp)
{
	clear_bit(LFL_AST_WAIT, &lp->flags);
	smp_mb__after_clear_bit();
	wake_up_bit(&lp->flags, LFL_AST_WAIT);
}

static void process_complete(struct gdlm_lock *lp)
{
	struct gdlm_ls *ls = lp->ls;
	struct lm_async_cb acb;
	s16 prev_mode = lp->cur;

	memset(&acb, 0, sizeof(acb));

	if (lp->lksb.sb_status == -DLM_ECANCEL) {
		log_info("complete dlm cancel %x,%llx flags %lx",
		 	 lp->lockname.ln_type,
			 (unsigned long long)lp->lockname.ln_number,
			 lp->flags);

		lp->req = lp->cur;
		acb.lc_ret |= LM_OUT_CANCELED;
		if (lp->cur == DLM_LOCK_IV)
			lp->lksb.sb_lkid = 0;
		goto out;
	}

	if (test_and_clear_bit(LFL_DLM_UNLOCK, &lp->flags)) {
		if (lp->lksb.sb_status != -DLM_EUNLOCK) {
			log_info("unlock sb_status %d %x,%llx flags %lx",
				 lp->lksb.sb_status, lp->lockname.ln_type,
				 (unsigned long long)lp->lockname.ln_number,
				 lp->flags);
			return;
		}

		lp->cur = DLM_LOCK_IV;
		lp->req = DLM_LOCK_IV;
		lp->lksb.sb_lkid = 0;

		if (test_and_clear_bit(LFL_UNLOCK_DELETE, &lp->flags)) {
			gdlm_delete_lp(lp);
			return;
		}
		goto out;
	}

	if (lp->lksb.sb_flags & DLM_SBF_VALNOTVALID)
		memset(lp->lksb.sb_lvbptr, 0, GDLM_LVB_SIZE);

	if (lp->lksb.sb_flags & DLM_SBF_ALTMODE) {
		if (lp->req == DLM_LOCK_PR)
			lp->req = DLM_LOCK_CW;
		else if (lp->req == DLM_LOCK_CW)
			lp->req = DLM_LOCK_PR;
	}

	/*
	 * A canceled lock request.  The lock was just taken off the delayed
	 * list and was never even submitted to dlm.
	 */

	if (test_and_clear_bit(LFL_CANCEL, &lp->flags)) {
		log_info("complete internal cancel %x,%llx",
		 	 lp->lockname.ln_type,
			 (unsigned long long)lp->lockname.ln_number);
		lp->req = lp->cur;
		acb.lc_ret |= LM_OUT_CANCELED;
		goto out;
	}

	/*
	 * An error occured.
	 */

	if (lp->lksb.sb_status) {
		/* a "normal" error */
		if ((lp->lksb.sb_status == -EAGAIN) &&
		    (lp->lkf & DLM_LKF_NOQUEUE)) {
			lp->req = lp->cur;
			if (lp->cur == DLM_LOCK_IV)
				lp->lksb.sb_lkid = 0;
			goto out;
		}

		/* this could only happen with cancels I think */
		log_info("ast sb_status %d %x,%llx flags %lx",
			 lp->lksb.sb_status, lp->lockname.ln_type,
			 (unsigned long long)lp->lockname.ln_number,
			 lp->flags);
		if (lp->lksb.sb_status == -EDEADLOCK &&
		    lp->ls->fsflags & LM_MFLAG_CONV_NODROP) {
			lp->req = lp->cur;
			acb.lc_ret |= LM_OUT_CONV_DEADLK;
			if (lp->cur == DLM_LOCK_IV)
				lp->lksb.sb_lkid = 0;
			goto out;
		} else
			return;
	}

	/*
	 * This is an AST for an EX->EX conversion for sync_lvb from GFS.
	 */

	if (test_and_clear_bit(LFL_SYNC_LVB, &lp->flags)) {
		wake_up_ast(lp);
		return;
	}

	/*
	 * A lock has been demoted to NL because it initially completed during
	 * BLOCK_LOCKS.  Now it must be requested in the originally requested
	 * mode.
	 */

	if (test_and_clear_bit(LFL_REREQUEST, &lp->flags)) {
		gdlm_assert(lp->req == DLM_LOCK_NL, "%x,%llx",
			    lp->lockname.ln_type,
			    (unsigned long long)lp->lockname.ln_number);
		gdlm_assert(lp->prev_req > DLM_LOCK_NL, "%x,%llx",
			    lp->lockname.ln_type,
			    (unsigned long long)lp->lockname.ln_number);

		lp->cur = DLM_LOCK_NL;
		lp->req = lp->prev_req;
		lp->prev_req = DLM_LOCK_IV;
		lp->lkf &= ~DLM_LKF_CONVDEADLK;

		set_bit(LFL_NOCACHE, &lp->flags);

		if (test_bit(DFL_BLOCK_LOCKS, &ls->flags) &&
		    !test_bit(LFL_NOBLOCK, &lp->flags))
			gdlm_queue_delayed(lp);
		else
			queue_submit(lp);
		return;
	}

	/*
	 * A request is granted during dlm recovery.  It may be granted
	 * because the locks of a failed node were cleared.  In that case,
	 * there may be inconsistent data beneath this lock and we must wait
	 * for recovery to complete to use it.  When gfs recovery is done this
	 * granted lock will be converted to NL and then reacquired in this
	 * granted state.
	 */

	if (test_bit(DFL_BLOCK_LOCKS, &ls->flags) &&
	    !test_bit(LFL_NOBLOCK, &lp->flags) &&
	    lp->req != DLM_LOCK_NL) {

		lp->cur = lp->req;
		lp->prev_req = lp->req;
		lp->req = DLM_LOCK_NL;
		lp->lkf |= DLM_LKF_CONVERT;
		lp->lkf &= ~DLM_LKF_CONVDEADLK;

		log_debug("rereq %x,%llx id %x %d,%d",
			  lp->lockname.ln_type,
			  (unsigned long long)lp->lockname.ln_number,
			  lp->lksb.sb_lkid, lp->cur, lp->req);

		set_bit(LFL_REREQUEST, &lp->flags);
		queue_submit(lp);
		return;
	}

	/*
	 * DLM demoted the lock to NL before it was granted so GFS must be
	 * told it cannot cache data for this lock.
	 */

	if (lp->lksb.sb_flags & DLM_SBF_DEMOTED)
		set_bit(LFL_NOCACHE, &lp->flags);

out:
	/*
	 * This is an internal lock_dlm lock
	 */

	if (test_bit(LFL_INLOCK, &lp->flags)) {
		clear_bit(LFL_NOBLOCK, &lp->flags);
		lp->cur = lp->req;
		wake_up_ast(lp);
		return;
	}

	/*
	 * Normal completion of a lock request.  Tell GFS it now has the lock.
	 */

	clear_bit(LFL_NOBLOCK, &lp->flags);
	lp->cur = lp->req;

	acb.lc_name = lp->lockname;
	acb.lc_ret |= gdlm_make_lmstate(lp->cur);

	if (!test_and_clear_bit(LFL_NOCACHE, &lp->flags) &&
	    (lp->cur > DLM_LOCK_NL) && (prev_mode > DLM_LOCK_NL))
		acb.lc_ret |= LM_OUT_CACHEABLE;

	ls->fscb(ls->sdp, LM_CB_ASYNC, &acb);
}

static inline int no_work(struct gdlm_ls *ls, int blocking)
{
	int ret;

	spin_lock(&ls->async_lock);
	ret = list_empty(&ls->complete) && list_empty(&ls->submit);
	if (ret && blocking)
		ret = list_empty(&ls->blocking);
	spin_unlock(&ls->async_lock);

	return ret;
}

static inline int check_drop(struct gdlm_ls *ls)
{
	if (!ls->drop_locks_count)
		return 0;

	if (time_after(jiffies, ls->drop_time + ls->drop_locks_period * HZ)) {
		ls->drop_time = jiffies;
		if (ls->all_locks_count >= ls->drop_locks_count)
			return 1;
	}
	return 0;
}

static int gdlm_thread(void *data, int blist)
{
	struct gdlm_ls *ls = (struct gdlm_ls *) data;
	struct gdlm_lock *lp = NULL;
	uint8_t complete, blocking, submit, drop;

	/* Only thread1 is allowed to do blocking callbacks since gfs
	   may wait for a completion callback within a blocking cb. */

	while (!kthread_should_stop()) {
		wait_event_interruptible(ls->thread_wait,
				!no_work(ls, blist) || kthread_should_stop());

		complete = blocking = submit = drop = 0;

		spin_lock(&ls->async_lock);

		if (blist && !list_empty(&ls->blocking)) {
			lp = list_entry(ls->blocking.next, struct gdlm_lock,
					blist);
			list_del_init(&lp->blist);
			blocking = lp->bast_mode;
			lp->bast_mode = 0;
		} else if (!list_empty(&ls->complete)) {
			lp = list_entry(ls->complete.next, struct gdlm_lock,
					clist);
			list_del_init(&lp->clist);
			complete = 1;
		} else if (!list_empty(&ls->submit)) {
			lp = list_entry(ls->submit.next, struct gdlm_lock,
					delay_list);
			list_del_init(&lp->delay_list);
			submit = 1;
		}

		drop = check_drop(ls);
		spin_unlock(&ls->async_lock);

		if (complete)
			process_complete(lp);

		else if (blocking)
			process_blocking(lp, blocking);

		else if (submit)
			gdlm_do_lock(lp);

		if (drop)
			ls->fscb(ls->sdp, LM_CB_DROPLOCKS, NULL);

		schedule();
	}

	return 0;
}

static int gdlm_thread1(void *data)
{
	return gdlm_thread(data, 1);
}

static int gdlm_thread2(void *data)
{
	return gdlm_thread(data, 0);
}

int gdlm_init_threads(struct gdlm_ls *ls)
{
	struct task_struct *p;
	int error;

	p = kthread_run(gdlm_thread1, ls, "lock_dlm1");
	error = IS_ERR(p);
	if (error) {
		log_error("can't start lock_dlm1 thread %d", error);
		return error;
	}
	ls->thread1 = p;

	p = kthread_run(gdlm_thread2, ls, "lock_dlm2");
	error = IS_ERR(p);
	if (error) {
		log_error("can't start lock_dlm2 thread %d", error);
		kthread_stop(ls->thread1);
		return error;
	}
	ls->thread2 = p;

	return 0;
}

void gdlm_release_threads(struct gdlm_ls *ls)
{
	kthread_stop(ls->thread1);
	kthread_stop(ls->thread2);
}

OpenPOWER on IntegriCloud