aboutsummaryrefslogtreecommitdiffstats
path: root/drivers/md/persistent-data/dm-space-map-disk.c
blob: cfbf9617e4658bd6aa84f45c840bda6f56a8402a (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
/*
 * Copyright (C) 2011 Red Hat, Inc.
 *
 * This file is released under the GPL.
 */

#include "dm-space-map-common.h"
#include "dm-space-map-disk.h"
#include "dm-space-map.h"
#include "dm-transaction-manager.h"

#include <linux/list.h>
#include <linux/slab.h>
#include <linux/export.h>
#include <linux/device-mapper.h>

#define DM_MSG_PREFIX "space map disk"

/*----------------------------------------------------------------*/

/*
 * Space map interface.
 */
struct sm_disk {
	struct dm_space_map sm;

	struct ll_disk ll;
	struct ll_disk old_ll;

	dm_block_t begin;
	dm_block_t nr_allocated_this_transaction;
};

static void sm_disk_destroy(struct dm_space_map *sm)
{
	struct sm_disk *smd = container_of(sm, struct sm_disk, sm);

	kfree(smd);
}

static int sm_disk_extend(struct dm_space_map *sm, dm_block_t extra_blocks)
{
	struct sm_disk *smd = container_of(sm, struct sm_disk, sm);

	return sm_ll_extend(&smd->ll, extra_blocks);
}

static int sm_disk_get_nr_blocks(struct dm_space_map *sm, dm_block_t *count)
{
	struct sm_disk *smd = container_of(sm, struct sm_disk, sm);
	*count = smd->old_ll.nr_blocks;

	return 0;
}

static int sm_disk_get_nr_free(struct dm_space_map *sm, dm_block_t *count)
{
	struct sm_disk *smd = container_of(sm, struct sm_disk, sm);
	*count = (smd->old_ll.nr_blocks - smd->old_ll.nr_allocated) - smd->nr_allocated_this_transaction;

	return 0;
}

static int sm_disk_get_count(struct dm_space_map *sm, dm_block_t b,
			     uint32_t *result)
{
	struct sm_disk *smd = container_of(sm, struct sm_disk, sm);
	return sm_ll_lookup(&smd->ll, b, result);
}

static int sm_disk_count_is_more_than_one(struct dm_space_map *sm, dm_block_t b,
					  int *result)
{
	int r;
	uint32_t count;

	r = sm_disk_get_count(sm, b, &count);
	if (r)
		return r;

	return count > 1;
}

static int sm_disk_set_count(struct dm_space_map *sm, dm_block_t b,
			     uint32_t count)
{
	int r;
	uint32_t old_count;
	enum allocation_event ev;
	struct sm_disk *smd = container_of(sm, struct sm_disk, sm);

	r = sm_ll_insert(&smd->ll, b, count, &ev);
	if (!r) {
		switch (ev) {
		case SM_NONE:
			break;

		case SM_ALLOC:
			/*
			 * This _must_ be free in the prior transaction
			 * otherwise we've lost atomicity.
			 */
			smd->nr_allocated_this_transaction++;
			break;

		case SM_FREE:
			/*
			 * It's only free if it's also free in the last
			 * transaction.
			 */
			r = sm_ll_lookup(&smd->old_ll, b, &old_count);
			if (r)
				return r;

			if (!old_count)
				smd->nr_allocated_this_transaction--;
			break;
		}
	}

	return r;
}

static int sm_disk_inc_block(struct dm_space_map *sm, dm_block_t b)
{
	int r;
	enum allocation_event ev;
	struct sm_disk *smd = container_of(sm, struct sm_disk, sm);

	r = sm_ll_inc(&smd->ll, b, &ev);
	if (!r && (ev == SM_ALLOC))
		/*
		 * This _must_ be free in the prior transaction
		 * otherwise we've lost atomicity.
		 */
		smd->nr_allocated_this_transaction++;

	return r;
}

static int sm_disk_dec_block(struct dm_space_map *sm, dm_block_t b)
{
	enum allocation_event ev;
	struct sm_disk *smd = container_of(sm, struct sm_disk, sm);

	return sm_ll_dec(&smd->ll, b, &ev);
}

static int sm_disk_new_block(struct dm_space_map *sm, dm_block_t *b)
{
	int r;
	enum allocation_event ev;
	struct sm_disk *smd = container_of(sm, struct sm_disk, sm);

	/* FIXME: we should loop round a couple of times */
	r = sm_ll_find_free_block(&smd->old_ll, smd->begin, smd->old_ll.nr_blocks, b);
	if (r)
		return r;

	smd->begin = *b + 1;
	r = sm_ll_inc(&smd->ll, *b, &ev);
	if (!r) {
		BUG_ON(ev != SM_ALLOC);
		smd->nr_allocated_this_transaction++;
	}

	return r;
}

static int sm_disk_commit(struct dm_space_map *sm)
{
	int r;
	dm_block_t nr_free;
	struct sm_disk *smd = container_of(sm, struct sm_disk, sm);

	r = sm_disk_get_nr_free(sm, &nr_free);
	if (r)
		return r;

	r = sm_ll_commit(&smd->ll);
	if (r)
		return r;

	memcpy(&smd->old_ll, &smd->ll, sizeof(smd->old_ll));
	smd->begin = 0;
	smd->nr_allocated_this_transaction = 0;

	r = sm_disk_get_nr_free(sm, &nr_free);
	if (r)
		return r;

	return 0;
}

static int sm_disk_root_size(struct dm_space_map *sm, size_t *result)
{
	*result = sizeof(struct disk_sm_root);

	return 0;
}

static int sm_disk_copy_root(struct dm_space_map *sm, void *where_le, size_t max)
{
	struct sm_disk *smd = container_of(sm, struct sm_disk, sm);
	struct disk_sm_root root_le;

	root_le.nr_blocks = cpu_to_le64(smd->ll.nr_blocks);
	root_le.nr_allocated = cpu_to_le64(smd->ll.nr_allocated);
	root_le.bitmap_root = cpu_to_le64(smd->ll.bitmap_root);
	root_le.ref_count_root = cpu_to_le64(smd->ll.ref_count_root);

	if (max < sizeof(root_le))
		return -ENOSPC;

	memcpy(where_le, &root_le, sizeof(root_le));

	return 0;
}

/*----------------------------------------------------------------*/

static struct dm_space_map ops = {
	.destroy = sm_disk_destroy,
	.extend = sm_disk_extend,
	.get_nr_blocks = sm_disk_get_nr_blocks,
	.get_nr_free = sm_disk_get_nr_free,
	.get_count = sm_disk_get_count,
	.count_is_more_than_one = sm_disk_count_is_more_than_one,
	.set_count = sm_disk_set_count,
	.inc_block = sm_disk_inc_block,
	.dec_block = sm_disk_dec_block,
	.new_block = sm_disk_new_block,
	.commit = sm_disk_commit,
	.root_size = sm_disk_root_size,
	.copy_root = sm_disk_copy_root,
	.register_threshold_callback = NULL
};

struct dm_space_map *dm_sm_disk_create(struct dm_transaction_manager *tm,
				       dm_block_t nr_blocks)
{
	int r;
	struct sm_disk *smd;

	smd = kmalloc(sizeof(*smd), GFP_KERNEL);
	if (!smd)
		return ERR_PTR(-ENOMEM);

	smd->begin = 0;
	smd->nr_allocated_this_transaction = 0;
	memcpy(&smd->sm, &ops, sizeof(smd->sm));

	r = sm_ll_new_disk(&smd->ll, tm);
	if (r)
		goto bad;

	r = sm_ll_extend(&smd->ll, nr_blocks);
	if (r)
		goto bad;

	r = sm_disk_commit(&smd->sm);
	if (r)
		goto bad;

	return &smd->sm;

bad:
	kfree(smd);
	return ERR_PTR(r);
}
EXPORT_SYMBOL_GPL(dm_sm_disk_create);

struct dm_space_map *dm_sm_disk_open(struct dm_transaction_manager *tm,
				     void *root_le, size_t len)
{
	int r;
	struct sm_disk *smd;

	smd = kmalloc(sizeof(*smd), GFP_KERNEL);
	if (!smd)
		return ERR_PTR(-ENOMEM);

	smd->begin = 0;
	smd->nr_allocated_this_transaction = 0;
	memcpy(&smd->sm, &ops, sizeof(smd->sm));

	r = sm_ll_open_disk(&smd->ll, tm, root_le, len);
	if (r)
		goto bad;

	r = sm_disk_commit(&smd->sm);
	if (r)
		goto bad;

	return &smd->sm;

bad:
	kfree(smd);
	return ERR_PTR(r);
}
EXPORT_SYMBOL_GPL(dm_sm_disk_open);

/*----------------------------------------------------------------*/

Privacy Policy