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 18 static int node_check(struct dm_block_validator *v, 19 struct dm_block *b, 20 size_t block_size); 21 22 static void node_prepare_for_write(struct dm_block_validator *v, 23 struct dm_block *b, 24 size_t block_size) 25 { 26 struct btree_node *n = dm_block_data(b); 27 struct node_header *h = &n->header; 28 29 h->blocknr = cpu_to_le64(dm_block_location(b)); 30 h->csum = cpu_to_le32(dm_bm_checksum(&h->flags, 31 block_size - sizeof(__le32), 32 BTREE_CSUM_XOR)); 33 34 BUG_ON(node_check(v, b, 4096)); 35 } 36 37 static int node_check(struct dm_block_validator *v, 38 struct dm_block *b, 39 size_t block_size) 40 { 41 struct btree_node *n = dm_block_data(b); 42 struct node_header *h = &n->header; 43 size_t value_size; 44 __le32 csum_disk; 45 uint32_t flags; 46 47 if (dm_block_location(b) != le64_to_cpu(h->blocknr)) { 48 DMERR_LIMIT("node_check failed: blocknr %llu != wanted %llu", 49 le64_to_cpu(h->blocknr), dm_block_location(b)); 50 return -ENOTBLK; 51 } 52 53 csum_disk = cpu_to_le32(dm_bm_checksum(&h->flags, 54 block_size - sizeof(__le32), 55 BTREE_CSUM_XOR)); 56 if (csum_disk != h->csum) { 57 DMERR_LIMIT("node_check failed: csum %u != wanted %u", 58 le32_to_cpu(csum_disk), le32_to_cpu(h->csum)); 59 return -EILSEQ; 60 } 61 62 value_size = le32_to_cpu(h->value_size); 63 64 if (sizeof(struct node_header) + 65 (sizeof(__le64) + value_size) * le32_to_cpu(h->max_entries) > block_size) { 66 DMERR_LIMIT("node_check failed: max_entries too large"); 67 return -EILSEQ; 68 } 69 70 if (le32_to_cpu(h->nr_entries) > le32_to_cpu(h->max_entries)) { 71 DMERR_LIMIT("node_check failed: too many entries"); 72 return -EILSEQ; 73 } 74 75 /* 76 * The node must be either INTERNAL or LEAF. 77 */ 78 flags = le32_to_cpu(h->flags); 79 if (!(flags & INTERNAL_NODE) && !(flags & LEAF_NODE)) { 80 DMERR_LIMIT("node_check failed: node is neither INTERNAL or LEAF"); 81 return -EILSEQ; 82 } 83 84 return 0; 85 } 86 87 struct dm_block_validator btree_node_validator = { 88 .name = "btree_node", 89 .prepare_for_write = node_prepare_for_write, 90 .check = node_check 91 }; 92 93 /*----------------------------------------------------------------*/ 94 95 int bn_read_lock(struct dm_btree_info *info, dm_block_t b, 96 struct dm_block **result) 97 { 98 return dm_tm_read_lock(info->tm, b, &btree_node_validator, result); 99 } 100 101 static int bn_shadow(struct dm_btree_info *info, dm_block_t orig, 102 struct dm_btree_value_type *vt, 103 struct dm_block **result) 104 { 105 int r, inc; 106 107 r = dm_tm_shadow_block(info->tm, orig, &btree_node_validator, 108 result, &inc); 109 if (!r && inc) 110 inc_children(info->tm, dm_block_data(*result), vt); 111 112 return r; 113 } 114 115 int new_block(struct dm_btree_info *info, struct dm_block **result) 116 { 117 return dm_tm_new_block(info->tm, &btree_node_validator, result); 118 } 119 120 void unlock_block(struct dm_btree_info *info, struct dm_block *b) 121 { 122 dm_tm_unlock(info->tm, b); 123 } 124 125 /*----------------------------------------------------------------*/ 126 127 void init_ro_spine(struct ro_spine *s, struct dm_btree_info *info) 128 { 129 s->info = info; 130 s->count = 0; 131 s->nodes[0] = NULL; 132 s->nodes[1] = NULL; 133 } 134 135 void exit_ro_spine(struct ro_spine *s) 136 { 137 int i; 138 139 for (i = 0; i < s->count; i++) { 140 unlock_block(s->info, s->nodes[i]); 141 } 142 } 143 144 int ro_step(struct ro_spine *s, dm_block_t new_child) 145 { 146 int r; 147 148 if (s->count == 2) { 149 unlock_block(s->info, s->nodes[0]); 150 s->nodes[0] = s->nodes[1]; 151 s->count--; 152 } 153 154 r = bn_read_lock(s->info, new_child, s->nodes + s->count); 155 if (!r) 156 s->count++; 157 158 return r; 159 } 160 161 void ro_pop(struct ro_spine *s) 162 { 163 BUG_ON(!s->count); 164 --s->count; 165 unlock_block(s->info, s->nodes[s->count]); 166 } 167 168 struct btree_node *ro_node(struct ro_spine *s) 169 { 170 struct dm_block *block; 171 172 BUG_ON(!s->count); 173 block = s->nodes[s->count - 1]; 174 175 return dm_block_data(block); 176 } 177 178 /*----------------------------------------------------------------*/ 179 180 void init_shadow_spine(struct shadow_spine *s, struct dm_btree_info *info) 181 { 182 s->info = info; 183 s->count = 0; 184 } 185 186 int exit_shadow_spine(struct shadow_spine *s) 187 { 188 int r = 0, i; 189 190 for (i = 0; i < s->count; i++) { 191 unlock_block(s->info, s->nodes[i]); 192 } 193 194 return r; 195 } 196 197 int shadow_step(struct shadow_spine *s, dm_block_t b, 198 struct dm_btree_value_type *vt) 199 { 200 int r; 201 202 if (s->count == 2) { 203 unlock_block(s->info, s->nodes[0]); 204 s->nodes[0] = s->nodes[1]; 205 s->count--; 206 } 207 208 r = bn_shadow(s->info, b, vt, s->nodes + s->count); 209 if (!r) { 210 if (!s->count) 211 s->root = dm_block_location(s->nodes[0]); 212 213 s->count++; 214 } 215 216 return r; 217 } 218 219 struct dm_block *shadow_current(struct shadow_spine *s) 220 { 221 BUG_ON(!s->count); 222 223 return s->nodes[s->count - 1]; 224 } 225 226 struct dm_block *shadow_parent(struct shadow_spine *s) 227 { 228 BUG_ON(s->count != 2); 229 230 return s->count == 2 ? s->nodes[0] : NULL; 231 } 232 233 int shadow_has_parent(struct shadow_spine *s) 234 { 235 return s->count >= 2; 236 } 237 238 int shadow_root(struct shadow_spine *s) 239 { 240 return s->root; 241 } 242 243 static void le64_inc(void *context, const void *value_le) 244 { 245 struct dm_transaction_manager *tm = context; 246 __le64 v_le; 247 248 memcpy(&v_le, value_le, sizeof(v_le)); 249 dm_tm_inc(tm, le64_to_cpu(v_le)); 250 } 251 252 static void le64_dec(void *context, const void *value_le) 253 { 254 struct dm_transaction_manager *tm = context; 255 __le64 v_le; 256 257 memcpy(&v_le, value_le, sizeof(v_le)); 258 dm_tm_dec(tm, le64_to_cpu(v_le)); 259 } 260 261 static int le64_equal(void *context, const void *value1_le, const void *value2_le) 262 { 263 __le64 v1_le, v2_le; 264 265 memcpy(&v1_le, value1_le, sizeof(v1_le)); 266 memcpy(&v2_le, value2_le, sizeof(v2_le)); 267 return v1_le == v2_le; 268 } 269 270 void init_le64_type(struct dm_transaction_manager *tm, 271 struct dm_btree_value_type *vt) 272 { 273 vt->context = tm; 274 vt->size = sizeof(__le64); 275 vt->inc = le64_inc; 276 vt->dec = le64_dec; 277 vt->equal = le64_equal; 278 } 279