1 /*
2  * Copyright (C) 2011 Red Hat, Inc.
3  *
4  * This file is released under the GPL.
5  */
6 
7 #include "dm-btree-internal.h"
8 #include "dm-transaction-manager.h"
9 
10 #include <linux/device-mapper.h>
11 
12 #define DM_MSG_PREFIX "btree spine"
13 
14 /*----------------------------------------------------------------*/
15 
16 #define BTREE_CSUM_XOR 121107
17 
node_prepare_for_write(struct dm_block_validator * v,struct dm_block * b,size_t block_size)18 static void node_prepare_for_write(struct dm_block_validator *v,
19 				   struct dm_block *b,
20 				   size_t block_size)
21 {
22 	struct btree_node *n = dm_block_data(b);
23 	struct node_header *h = &n->header;
24 
25 	h->blocknr = cpu_to_le64(dm_block_location(b));
26 	h->csum = cpu_to_le32(dm_bm_checksum(&h->flags,
27 					     block_size - sizeof(__le32),
28 					     BTREE_CSUM_XOR));
29 }
30 
node_check(struct dm_block_validator * v,struct dm_block * b,size_t block_size)31 static int node_check(struct dm_block_validator *v,
32 		      struct dm_block *b,
33 		      size_t block_size)
34 {
35 	struct btree_node *n = dm_block_data(b);
36 	struct node_header *h = &n->header;
37 	size_t value_size;
38 	__le32 csum_disk;
39 	uint32_t flags, nr_entries, max_entries;
40 
41 	if (dm_block_location(b) != le64_to_cpu(h->blocknr)) {
42 		DMERR_LIMIT("node_check failed: blocknr %llu != wanted %llu",
43 			    le64_to_cpu(h->blocknr), dm_block_location(b));
44 		return -ENOTBLK;
45 	}
46 
47 	csum_disk = cpu_to_le32(dm_bm_checksum(&h->flags,
48 					       block_size - sizeof(__le32),
49 					       BTREE_CSUM_XOR));
50 	if (csum_disk != h->csum) {
51 		DMERR_LIMIT("node_check failed: csum %u != wanted %u",
52 			    le32_to_cpu(csum_disk), le32_to_cpu(h->csum));
53 		return -EILSEQ;
54 	}
55 
56 	nr_entries = le32_to_cpu(h->nr_entries);
57 	max_entries = le32_to_cpu(h->max_entries);
58 	value_size = le32_to_cpu(h->value_size);
59 
60 	if (sizeof(struct node_header) +
61 	    (sizeof(__le64) + value_size) * max_entries > block_size) {
62 		DMERR_LIMIT("node_check failed: max_entries too large");
63 		return -EILSEQ;
64 	}
65 
66 	if (nr_entries > max_entries) {
67 		DMERR_LIMIT("node_check failed: too many entries");
68 		return -EILSEQ;
69 	}
70 
71 	/*
72 	 * The node must be either INTERNAL or LEAF.
73 	 */
74 	flags = le32_to_cpu(h->flags);
75 	if (!(flags & INTERNAL_NODE) && !(flags & LEAF_NODE)) {
76 		DMERR_LIMIT("node_check failed: node is neither INTERNAL or LEAF");
77 		return -EILSEQ;
78 	}
79 
80 	return 0;
81 }
82 
83 struct dm_block_validator btree_node_validator = {
84 	.name = "btree_node",
85 	.prepare_for_write = node_prepare_for_write,
86 	.check = node_check
87 };
88 
89 /*----------------------------------------------------------------*/
90 
bn_read_lock(struct dm_btree_info * info,dm_block_t b,struct dm_block ** result)91 int bn_read_lock(struct dm_btree_info *info, dm_block_t b,
92 		 struct dm_block **result)
93 {
94 	return dm_tm_read_lock(info->tm, b, &btree_node_validator, result);
95 }
96 
bn_shadow(struct dm_btree_info * info,dm_block_t orig,struct dm_btree_value_type * vt,struct dm_block ** result)97 static int bn_shadow(struct dm_btree_info *info, dm_block_t orig,
98 	      struct dm_btree_value_type *vt,
99 	      struct dm_block **result)
100 {
101 	int r, inc;
102 
103 	r = dm_tm_shadow_block(info->tm, orig, &btree_node_validator,
104 			       result, &inc);
105 	if (!r && inc)
106 		inc_children(info->tm, dm_block_data(*result), vt);
107 
108 	return r;
109 }
110 
new_block(struct dm_btree_info * info,struct dm_block ** result)111 int new_block(struct dm_btree_info *info, struct dm_block **result)
112 {
113 	return dm_tm_new_block(info->tm, &btree_node_validator, result);
114 }
115 
unlock_block(struct dm_btree_info * info,struct dm_block * b)116 void unlock_block(struct dm_btree_info *info, struct dm_block *b)
117 {
118 	dm_tm_unlock(info->tm, b);
119 }
120 
121 /*----------------------------------------------------------------*/
122 
init_ro_spine(struct ro_spine * s,struct dm_btree_info * info)123 void init_ro_spine(struct ro_spine *s, struct dm_btree_info *info)
124 {
125 	s->info = info;
126 	s->count = 0;
127 	s->nodes[0] = NULL;
128 	s->nodes[1] = NULL;
129 }
130 
exit_ro_spine(struct ro_spine * s)131 void exit_ro_spine(struct ro_spine *s)
132 {
133 	int i;
134 
135 	for (i = 0; i < s->count; i++) {
136 		unlock_block(s->info, s->nodes[i]);
137 	}
138 }
139 
ro_step(struct ro_spine * s,dm_block_t new_child)140 int 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 
ro_pop(struct ro_spine * s)157 void 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 
ro_node(struct ro_spine * s)164 struct 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 
init_shadow_spine(struct shadow_spine * s,struct dm_btree_info * info)176 void init_shadow_spine(struct shadow_spine *s, struct dm_btree_info *info)
177 {
178 	s->info = info;
179 	s->count = 0;
180 }
181 
exit_shadow_spine(struct shadow_spine * s)182 void 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 }
190 
shadow_step(struct shadow_spine * s,dm_block_t b,struct dm_btree_value_type * vt)191 int shadow_step(struct shadow_spine *s, dm_block_t b,
192 		struct dm_btree_value_type *vt)
193 {
194 	int r;
195 
196 	if (s->count == 2) {
197 		unlock_block(s->info, s->nodes[0]);
198 		s->nodes[0] = s->nodes[1];
199 		s->count--;
200 	}
201 
202 	r = bn_shadow(s->info, b, vt, s->nodes + s->count);
203 	if (!r) {
204 		if (!s->count)
205 			s->root = dm_block_location(s->nodes[0]);
206 
207 		s->count++;
208 	}
209 
210 	return r;
211 }
212 
shadow_current(struct shadow_spine * s)213 struct dm_block *shadow_current(struct shadow_spine *s)
214 {
215 	BUG_ON(!s->count);
216 
217 	return s->nodes[s->count - 1];
218 }
219 
shadow_parent(struct shadow_spine * s)220 struct dm_block *shadow_parent(struct shadow_spine *s)
221 {
222 	BUG_ON(s->count != 2);
223 
224 	return s->count == 2 ? s->nodes[0] : NULL;
225 }
226 
shadow_has_parent(struct shadow_spine * s)227 int shadow_has_parent(struct shadow_spine *s)
228 {
229 	return s->count >= 2;
230 }
231 
shadow_root(struct shadow_spine * s)232 dm_block_t shadow_root(struct shadow_spine *s)
233 {
234 	return s->root;
235 }
236 
le64_inc(void * context,const void * value_le,unsigned count)237 static void le64_inc(void *context, const void *value_le, unsigned count)
238 {
239 	dm_tm_with_runs(context, value_le, count, dm_tm_inc_range);
240 }
241 
le64_dec(void * context,const void * value_le,unsigned count)242 static void le64_dec(void *context, const void *value_le, unsigned count)
243 {
244 	dm_tm_with_runs(context, value_le, count, dm_tm_dec_range);
245 }
246 
le64_equal(void * context,const void * value1_le,const void * value2_le)247 static int le64_equal(void *context, const void *value1_le, const void *value2_le)
248 {
249 	__le64 v1_le, v2_le;
250 
251 	memcpy(&v1_le, value1_le, sizeof(v1_le));
252 	memcpy(&v2_le, value2_le, sizeof(v2_le));
253 	return v1_le == v2_le;
254 }
255 
init_le64_type(struct dm_transaction_manager * tm,struct dm_btree_value_type * vt)256 void init_le64_type(struct dm_transaction_manager *tm,
257 		    struct dm_btree_value_type *vt)
258 {
259 	vt->context = tm;
260 	vt->size = sizeof(__le64);
261 	vt->inc = le64_inc;
262 	vt->dec = le64_dec;
263 	vt->equal = le64_equal;
264 }
265