summaryrefslogtreecommitdiffstats
path: root/drivers/md/persistent-data/dm-btree-spine.c
blob: 45a39d4f1c10fbcea55604595011a76b1f072bc8 (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
/*
 * Copyright (C) 2011 Red Hat, Inc.
 *
 * This file is released under the GPL.
 */

#include "dm-btree-internal.h"
#include "dm-transaction-manager.h"

#include <linux/device-mapper.h>

#define DM_MSG_PREFIX "btree spine"

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

#define BTREE_CSUM_XOR 121107

static void node_prepare_for_write(struct dm_block_validator *v,
				   struct dm_block *b,
				   size_t block_size)
{
	struct btree_node *n = dm_block_data(b);
	struct node_header *h = &n->header;

	h->blocknr = cpu_to_le64(dm_block_location(b));
	h->csum = cpu_to_le32(dm_bm_checksum(&h->flags,
					     block_size - sizeof(__le32),
					     BTREE_CSUM_XOR));
}

static int node_check(struct dm_block_validator *v,
		      struct dm_block *b,
		      size_t block_size)
{
	struct btree_node *n = dm_block_data(b);
	struct node_header *h = &n->header;
	size_t value_size;
	__le32 csum_disk;
	uint32_t flags, nr_entries, max_entries;

	if (dm_block_location(b) != le64_to_cpu(h->blocknr)) {
		DMERR_LIMIT("node_check failed: blocknr %llu != wanted %llu",
			    le64_to_cpu(h->blocknr), dm_block_location(b));
		return -ENOTBLK;
	}

	csum_disk = cpu_to_le32(dm_bm_checksum(&h->flags,
					       block_size - sizeof(__le32),
					       BTREE_CSUM_XOR));
	if (csum_disk != h->csum) {
		DMERR_LIMIT("node_check failed: csum %u != wanted %u",
			    le32_to_cpu(csum_disk), le32_to_cpu(h->csum));
		return -EILSEQ;
	}

	nr_entries = le32_to_cpu(h->nr_entries);
	max_entries = le32_to_cpu(h->max_entries);
	value_size = le32_to_cpu(h->value_size);

	if (sizeof(struct node_header) +
	    (sizeof(__le64) + value_size) * max_entries > block_size) {
		DMERR_LIMIT("node_check failed: max_entries too large");
		return -EILSEQ;
	}

	if (nr_entries > max_entries) {
		DMERR_LIMIT("node_check failed: too many entries");
		return -EILSEQ;
	}

	/*
	 * The node must be either INTERNAL or LEAF.
	 */
	flags = le32_to_cpu(h->flags);
	if (!(flags & INTERNAL_NODE) && !(flags & LEAF_NODE)) {
		DMERR_LIMIT("node_check failed: node is neither INTERNAL or LEAF");
		return -EILSEQ;
	}

	return 0;
}

struct dm_block_validator btree_node_validator = {
	.name = "btree_node",
	.prepare_for_write = node_prepare_for_write,
	.check = node_check
};

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

int bn_read_lock(struct dm_btree_info *info, dm_block_t b,
		 struct dm_block **result)
{
	return dm_tm_read_lock(info->tm, b, &btree_node_validator, result);
}

static int bn_shadow(struct dm_btree_info *info, dm_block_t orig,
	      struct dm_btree_value_type *vt,
	      struct dm_block **result)
{
	int r, inc;

	r = dm_tm_shadow_block(info->tm, orig, &btree_node_validator,
			       result, &inc);
	if (!r && inc)
		inc_children(info->tm, dm_block_data(*result), vt);

	return r;
}

int new_block(struct dm_btree_info *info, struct dm_block **result)
{
	return dm_tm_new_block(info->tm, &btree_node_validator, result);
}

void unlock_block(struct dm_btree_info *info, struct dm_block *b)
{
	dm_tm_unlock(info->tm, b);
}

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

void init_ro_spine(struct ro_spine *s, struct dm_btree_info *info)
{
	s->info = info;
	s->count = 0;
	s->nodes[0] = NULL;
	s->nodes[1] = NULL;
}

void exit_ro_spine(struct ro_spine *s)
{
	int i;

	for (i = 0; i < s->count; i++) {
		unlock_block(s->info, s->nodes[i]);
	}
}

int ro_step(struct ro_spine *s, dm_block_t new_child)
{
	int r;

	if (s->count == 2) {
		unlock_block(s->info, s->nodes[0]);
		s->nodes[0] = s->nodes[1];
		s->count--;
	}

	r = bn_read_lock(s->info, new_child, s->nodes + s->count);
	if (!r)
		s->count++;

	return r;
}

void ro_pop(struct ro_spine *s)
{
	BUG_ON(!s->count);
	--s->count;
	unlock_block(s->info, s->nodes[s->count]);
}

struct btree_node *ro_node(struct ro_spine *s)
{
	struct dm_block *block;

	BUG_ON(!s->count);
	block = s->nodes[s->count - 1];

	return dm_block_data(block);
}

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

void init_shadow_spine(struct shadow_spine *s, struct dm_btree_info *info)
{
	s->info = info;
	s->count = 0;
}

void exit_shadow_spine(struct shadow_spine *s)
{
	int i;

	for (i = 0; i < s->count; i++) {
		unlock_block(s->info, s->nodes[i]);
	}
}

int shadow_step(struct shadow_spine *s, dm_block_t b,
		struct dm_btree_value_type *vt)
{
	int r;

	if (s->count == 2) {
		unlock_block(s->info, s->nodes[0]);
		s->nodes[0] = s->nodes[1];
		s->count--;
	}

	r = bn_shadow(s->info, b, vt, s->nodes + s->count);
	if (!r) {
		if (!s->count)
			s->root = dm_block_location(s->nodes[0]);

		s->count++;
	}

	return r;
}

struct dm_block *shadow_current(struct shadow_spine *s)
{
	BUG_ON(!s->count);

	return s->nodes[s->count - 1];
}

struct dm_block *shadow_parent(struct shadow_spine *s)
{
	BUG_ON(s->count != 2);

	return s->count == 2 ? s->nodes[0] : NULL;
}

int shadow_has_parent(struct shadow_spine *s)
{
	return s->count >= 2;
}

dm_block_t shadow_root(struct shadow_spine *s)
{
	return s->root;
}

static void le64_inc(void *context, const void *value_le, unsigned int count)
{
	dm_tm_with_runs(context, value_le, count, dm_tm_inc_range);
}

static void le64_dec(void *context, const void *value_le, unsigned int count)
{
	dm_tm_with_runs(context, value_le, count, dm_tm_dec_range);
}

static int le64_equal(void *context, const void *value1_le, const void *value2_le)
{
	__le64 v1_le, v2_le;

	memcpy(&v1_le, value1_le, sizeof(v1_le));
	memcpy(&v2_le, value2_le, sizeof(v2_le));
	return v1_le == v2_le;
}

void init_le64_type(struct dm_transaction_manager *tm,
		    struct dm_btree_value_type *vt)
{
	vt->context = tm;
	vt->size = sizeof(__le64);
	vt->inc = le64_inc;
	vt->dec = le64_dec;
	vt->equal = le64_equal;
}