1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (C) 2011 Red Hat, Inc.
4 *
5 * This file is released under the GPL.
6 */
7
8#include "dm-btree-internal.h"
9#include "dm-transaction-manager.h"
10
11#include <linux/device-mapper.h>
12
13#define DM_MSG_PREFIX "btree spine"
14
15/*----------------------------------------------------------------*/
16
17#define BTREE_CSUM_XOR 121107
18
19static void node_prepare_for_write(struct dm_block_validator *v,
20				   struct dm_block *b,
21				   size_t block_size)
22{
23	struct btree_node *n = dm_block_data(b);
24	struct node_header *h = &n->header;
25
26	h->blocknr = cpu_to_le64(dm_block_location(b));
27	h->csum = cpu_to_le32(dm_bm_checksum(&h->flags,
28					     block_size - sizeof(__le32),
29					     BTREE_CSUM_XOR));
30}
31
32static int node_check(struct dm_block_validator *v,
33		      struct dm_block *b,
34		      size_t block_size)
35{
36	struct btree_node *n = dm_block_data(b);
37	struct node_header *h = &n->header;
38	size_t value_size;
39	__le32 csum_disk;
40	uint32_t flags, nr_entries, max_entries;
41
42	if (dm_block_location(b) != le64_to_cpu(h->blocknr)) {
43		DMERR_LIMIT("%s failed: blocknr %llu != wanted %llu", __func__,
44			    le64_to_cpu(h->blocknr), dm_block_location(b));
45		return -ENOTBLK;
46	}
47
48	csum_disk = cpu_to_le32(dm_bm_checksum(&h->flags,
49					       block_size - sizeof(__le32),
50					       BTREE_CSUM_XOR));
51	if (csum_disk != h->csum) {
52		DMERR_LIMIT("%s failed: csum %u != wanted %u", __func__,
53			    le32_to_cpu(csum_disk), le32_to_cpu(h->csum));
54		return -EILSEQ;
55	}
56
57	nr_entries = le32_to_cpu(h->nr_entries);
58	max_entries = le32_to_cpu(h->max_entries);
59	value_size = le32_to_cpu(h->value_size);
60
61	if (sizeof(struct node_header) +
62	    (sizeof(__le64) + value_size) * max_entries > block_size) {
63		DMERR_LIMIT("%s failed: max_entries too large", __func__);
64		return -EILSEQ;
65	}
66
67	if (nr_entries > max_entries) {
68		DMERR_LIMIT("%s failed: too many entries", __func__);
69		return -EILSEQ;
70	}
71
72	/*
73	 * The node must be either INTERNAL or LEAF.
74	 */
75	flags = le32_to_cpu(h->flags);
76	if (!(flags & INTERNAL_NODE) && !(flags & LEAF_NODE)) {
77		DMERR_LIMIT("%s failed: node is neither INTERNAL or LEAF", __func__);
78		return -EILSEQ;
79	}
80
81	return 0;
82}
83
84struct dm_block_validator btree_node_validator = {
85	.name = "btree_node",
86	.prepare_for_write = node_prepare_for_write,
87	.check = node_check
88};
89
90/*----------------------------------------------------------------*/
91
92int bn_read_lock(struct dm_btree_info *info, dm_block_t b,
93		 struct dm_block **result)
94{
95	return dm_tm_read_lock(info->tm, b, &btree_node_validator, result);
96}
97
98static int bn_shadow(struct dm_btree_info *info, dm_block_t orig,
99	      struct dm_btree_value_type *vt,
100	      struct dm_block **result)
101{
102	int r, inc;
103
104	r = dm_tm_shadow_block(info->tm, orig, &btree_node_validator,
105			       result, &inc);
106	if (!r && inc)
107		inc_children(info->tm, dm_block_data(*result), vt);
108
109	return r;
110}
111
112int new_block(struct dm_btree_info *info, struct dm_block **result)
113{
114	return dm_tm_new_block(info->tm, &btree_node_validator, result);
115}
116
117void unlock_block(struct dm_btree_info *info, struct dm_block *b)
118{
119	dm_tm_unlock(info->tm, b);
120}
121
122/*----------------------------------------------------------------*/
123
124void init_ro_spine(struct ro_spine *s, struct dm_btree_info *info)
125{
126	s->info = info;
127	s->count = 0;
128	s->nodes[0] = NULL;
129	s->nodes[1] = NULL;
130}
131
132void exit_ro_spine(struct ro_spine *s)
133{
134	int i;
135
136	for (i = 0; i < s->count; i++)
137		unlock_block(s->info, s->nodes[i]);
138}
139
140int ro_step(struct ro_spine *s, dm_block_t new_child)
141{
142	int r;
143
144	if (s->count == 2) {
145		unlock_block(s->info, s->nodes[0]);
146		s->nodes[0] = s->nodes[1];
147		s->count--;
148	}
149
150	r = bn_read_lock(s->info, new_child, s->nodes + s->count);
151	if (!r)
152		s->count++;
153
154	return r;
155}
156
157void ro_pop(struct ro_spine *s)
158{
159	BUG_ON(!s->count);
160	--s->count;
161	unlock_block(s->info, s->nodes[s->count]);
162}
163
164struct btree_node *ro_node(struct ro_spine *s)
165{
166	struct dm_block *block;
167
168	BUG_ON(!s->count);
169	block = s->nodes[s->count - 1];
170
171	return dm_block_data(block);
172}
173
174/*----------------------------------------------------------------*/
175
176void init_shadow_spine(struct shadow_spine *s, struct dm_btree_info *info)
177{
178	s->info = info;
179	s->count = 0;
180}
181
182void exit_shadow_spine(struct shadow_spine *s)
183{
184	int i;
185
186	for (i = 0; i < s->count; i++)
187		unlock_block(s->info, s->nodes[i]);
188}
189
190int shadow_step(struct shadow_spine *s, dm_block_t b,
191		struct dm_btree_value_type *vt)
192{
193	int r;
194
195	if (s->count == 2) {
196		unlock_block(s->info, s->nodes[0]);
197		s->nodes[0] = s->nodes[1];
198		s->count--;
199	}
200
201	r = bn_shadow(s->info, b, vt, s->nodes + s->count);
202	if (!r) {
203		if (!s->count)
204			s->root = dm_block_location(s->nodes[0]);
205
206		s->count++;
207	}
208
209	return r;
210}
211
212struct dm_block *shadow_current(struct shadow_spine *s)
213{
214	BUG_ON(!s->count);
215
216	return s->nodes[s->count - 1];
217}
218
219struct dm_block *shadow_parent(struct shadow_spine *s)
220{
221	BUG_ON(s->count != 2);
222
223	return s->count == 2 ? s->nodes[0] : NULL;
224}
225
226int shadow_has_parent(struct shadow_spine *s)
227{
228	return s->count >= 2;
229}
230
231dm_block_t shadow_root(struct shadow_spine *s)
232{
233	return s->root;
234}
235
236static void le64_inc(void *context, const void *value_le, unsigned int count)
237{
238	dm_tm_with_runs(context, value_le, count, dm_tm_inc_range);
239}
240
241static void le64_dec(void *context, const void *value_le, unsigned int count)
242{
243	dm_tm_with_runs(context, value_le, count, dm_tm_dec_range);
244}
245
246static int le64_equal(void *context, const void *value1_le, const void *value2_le)
247{
248	__le64 v1_le, v2_le;
249
250	memcpy(&v1_le, value1_le, sizeof(v1_le));
251	memcpy(&v2_le, value2_le, sizeof(v2_le));
252	return v1_le == v2_le;
253}
254
255void init_le64_type(struct dm_transaction_manager *tm,
256		    struct dm_btree_value_type *vt)
257{
258	vt->context = tm;
259	vt->size = sizeof(__le64);
260	vt->inc = le64_inc;
261	vt->dec = le64_dec;
262	vt->equal = le64_equal;
263}
264