summaryrefslogtreecommitdiffstats
path: root/fs/dlm/ast.c
blob: decedc4ee15f6d365d9dd54068bc2160bd8b44cf (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
// SPDX-License-Identifier: GPL-2.0-only
/******************************************************************************
*******************************************************************************
**
**  Copyright (C) Sistina Software, Inc.  1997-2003  All rights reserved.
**  Copyright (C) 2004-2010 Red Hat, Inc.  All rights reserved.
**
**
*******************************************************************************
******************************************************************************/

#include <trace/events/dlm.h>

#include "dlm_internal.h"
#include "lvb_table.h"
#include "memory.h"
#include "lock.h"
#include "user.h"
#include "ast.h"

void dlm_release_callback(struct kref *ref)
{
	struct dlm_callback *cb = container_of(ref, struct dlm_callback, ref);

	dlm_free_cb(cb);
}

void dlm_callback_set_last_ptr(struct dlm_callback **from,
			       struct dlm_callback *to)
{
	if (*from)
		kref_put(&(*from)->ref, dlm_release_callback);

	if (to)
		kref_get(&to->ref);

	*from = to;
}

int dlm_enqueue_lkb_callback(struct dlm_lkb *lkb, uint32_t flags, int mode,
			     int status, uint32_t sbflags)
{
	struct dlm_ls *ls = lkb->lkb_resource->res_ls;
	int rv = DLM_ENQUEUE_CALLBACK_SUCCESS;
	struct dlm_callback *cb;
	int copy_lvb = 0;
	int prev_mode;

	if (flags & DLM_CB_BAST) {
		/* if cb is a bast, it should be skipped if the blocking mode is
		 * compatible with the last granted mode
		 */
		if (lkb->lkb_last_cast) {
			if (dlm_modes_compat(mode, lkb->lkb_last_cast->mode)) {
				log_debug(ls, "skip %x bast mode %d for cast mode %d",
					  lkb->lkb_id, mode,
					  lkb->lkb_last_cast->mode);
				goto out;
			}
		}

		/*
		 * Suppress some redundant basts here, do more on removal.
		 * Don't even add a bast if the callback just before it
		 * is a bast for the same mode or a more restrictive mode.
		 * (the addional > PR check is needed for PR/CW inversion)
		 */
		if (lkb->lkb_last_cb && lkb->lkb_last_cb->flags & DLM_CB_BAST) {
			prev_mode = lkb->lkb_last_cb->mode;

			if ((prev_mode == mode) ||
			    (prev_mode > mode && prev_mode > DLM_LOCK_PR)) {
				log_debug(ls, "skip %x add bast mode %d for bast mode %d",
					  lkb->lkb_id, mode, prev_mode);
				goto out;
			}
		}
	} else if (flags & DLM_CB_CAST) {
		if (test_bit(DLM_DFL_USER_BIT, &lkb->lkb_dflags)) {
			if (lkb->lkb_last_cast)
				prev_mode = lkb->lkb_last_cb->mode;
			else
				prev_mode = -1;

			if (!status && lkb->lkb_lksb->sb_lvbptr &&
			    dlm_lvb_operations[prev_mode + 1][mode + 1])
				copy_lvb = 1;
		}
	}

	cb = dlm_allocate_cb();
	if (!cb) {
		rv = DLM_ENQUEUE_CALLBACK_FAILURE;
		goto out;
	}

	cb->flags = flags;
	cb->mode = mode;
	cb->sb_status = status;
	cb->sb_flags = (sbflags & 0x000000FF);
	cb->copy_lvb = copy_lvb;
	kref_init(&cb->ref);
	if (!test_and_set_bit(DLM_IFL_CB_PENDING_BIT, &lkb->lkb_iflags))
		rv = DLM_ENQUEUE_CALLBACK_NEED_SCHED;

	list_add_tail(&cb->list, &lkb->lkb_callbacks);

	if (flags & DLM_CB_CAST)
		dlm_callback_set_last_ptr(&lkb->lkb_last_cast, cb);

	dlm_callback_set_last_ptr(&lkb->lkb_last_cb, cb);

 out:
	return rv;
}

int dlm_dequeue_lkb_callback(struct dlm_lkb *lkb, struct dlm_callback **cb)
{
	/* oldest undelivered cb is callbacks first entry */
	*cb = list_first_entry_or_null(&lkb->lkb_callbacks,
				       struct dlm_callback, list);
	if (!*cb)
		return DLM_DEQUEUE_CALLBACK_EMPTY;

	/* remove it from callbacks so shift others down */
	list_del(&(*cb)->list);
	if (list_empty(&lkb->lkb_callbacks))
		return DLM_DEQUEUE_CALLBACK_LAST;

	return DLM_DEQUEUE_CALLBACK_SUCCESS;
}

void dlm_add_cb(struct dlm_lkb *lkb, uint32_t flags, int mode, int status,
		uint32_t sbflags)
{
	struct dlm_ls *ls = lkb->lkb_resource->res_ls;
	int rv;

	if (test_bit(DLM_DFL_USER_BIT, &lkb->lkb_dflags)) {
		dlm_user_add_ast(lkb, flags, mode, status, sbflags);
		return;
	}

	spin_lock(&lkb->lkb_cb_lock);
	rv = dlm_enqueue_lkb_callback(lkb, flags, mode, status, sbflags);
	switch (rv) {
	case DLM_ENQUEUE_CALLBACK_NEED_SCHED:
		kref_get(&lkb->lkb_ref);

		spin_lock(&ls->ls_cb_lock);
		if (test_bit(LSFL_CB_DELAY, &ls->ls_flags)) {
			list_add(&lkb->lkb_cb_list, &ls->ls_cb_delay);
		} else {
			queue_work(ls->ls_callback_wq, &lkb->lkb_cb_work);
		}
		spin_unlock(&ls->ls_cb_lock);
		break;
	case DLM_ENQUEUE_CALLBACK_FAILURE:
		WARN_ON_ONCE(1);
		break;
	case DLM_ENQUEUE_CALLBACK_SUCCESS:
		break;
	default:
		WARN_ON_ONCE(1);
		break;
	}
	spin_unlock(&lkb->lkb_cb_lock);
}

void dlm_callback_work(struct work_struct *work)
{
	struct dlm_lkb *lkb = container_of(work, struct dlm_lkb, lkb_cb_work);
	struct dlm_ls *ls = lkb->lkb_resource->res_ls;
	void (*castfn) (void *astparam);
	void (*bastfn) (void *astparam, int mode);
	struct dlm_callback *cb;
	int rv;

	spin_lock(&lkb->lkb_cb_lock);
	rv = dlm_dequeue_lkb_callback(lkb, &cb);
	if (WARN_ON_ONCE(rv == DLM_DEQUEUE_CALLBACK_EMPTY)) {
		clear_bit(DLM_IFL_CB_PENDING_BIT, &lkb->lkb_iflags);
		spin_unlock(&lkb->lkb_cb_lock);
		goto out;
	}
	spin_unlock(&lkb->lkb_cb_lock);

	for (;;) {
		castfn = lkb->lkb_astfn;
		bastfn = lkb->lkb_bastfn;

		if (cb->flags & DLM_CB_BAST) {
			trace_dlm_bast(ls, lkb, cb->mode);
			lkb->lkb_last_bast_time = ktime_get();
			lkb->lkb_last_bast_mode = cb->mode;
			bastfn(lkb->lkb_astparam, cb->mode);
		} else if (cb->flags & DLM_CB_CAST) {
			lkb->lkb_lksb->sb_status = cb->sb_status;
			lkb->lkb_lksb->sb_flags = cb->sb_flags;
			trace_dlm_ast(ls, lkb);
			lkb->lkb_last_cast_time = ktime_get();
			castfn(lkb->lkb_astparam);
		}

		kref_put(&cb->ref, dlm_release_callback);

		spin_lock(&lkb->lkb_cb_lock);
		rv = dlm_dequeue_lkb_callback(lkb, &cb);
		if (rv == DLM_DEQUEUE_CALLBACK_EMPTY) {
			clear_bit(DLM_IFL_CB_PENDING_BIT, &lkb->lkb_iflags);
			spin_unlock(&lkb->lkb_cb_lock);
			break;
		}
		spin_unlock(&lkb->lkb_cb_lock);
	}

out:
	/* undo kref_get from dlm_add_callback, may cause lkb to be freed */
	dlm_put_lkb(lkb);
}

int dlm_callback_start(struct dlm_ls *ls)
{
	ls->ls_callback_wq = alloc_workqueue("dlm_callback",
					     WQ_HIGHPRI | WQ_MEM_RECLAIM, 0);
	if (!ls->ls_callback_wq) {
		log_print("can't start dlm_callback workqueue");
		return -ENOMEM;
	}
	return 0;
}

void dlm_callback_stop(struct dlm_ls *ls)
{
	if (ls->ls_callback_wq)
		destroy_workqueue(ls->ls_callback_wq);
}

void dlm_callback_suspend(struct dlm_ls *ls)
{
	if (ls->ls_callback_wq) {
		spin_lock(&ls->ls_cb_lock);
		set_bit(LSFL_CB_DELAY, &ls->ls_flags);
		spin_unlock(&ls->ls_cb_lock);

		flush_workqueue(ls->ls_callback_wq);
	}
}

#define MAX_CB_QUEUE 25

void dlm_callback_resume(struct dlm_ls *ls)
{
	struct dlm_lkb *lkb, *safe;
	int count = 0, sum = 0;
	bool empty;

	if (!ls->ls_callback_wq)
		return;

more:
	spin_lock(&ls->ls_cb_lock);
	list_for_each_entry_safe(lkb, safe, &ls->ls_cb_delay, lkb_cb_list) {
		list_del_init(&lkb->lkb_cb_list);
		queue_work(ls->ls_callback_wq, &lkb->lkb_cb_work);
		count++;
		if (count == MAX_CB_QUEUE)
			break;
	}
	empty = list_empty(&ls->ls_cb_delay);
	if (empty)
		clear_bit(LSFL_CB_DELAY, &ls->ls_flags);
	spin_unlock(&ls->ls_cb_lock);

	sum += count;
	if (!empty) {
		count = 0;
		cond_resched();
		goto more;
	}

	if (sum)
		log_rinfo(ls, "%s %d", __func__, sum);
}