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 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 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 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 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 } 110 111 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 } 115 116 void unlock_block(struct dm_btree_info *info, struct dm_block *b) 117 { 118 dm_tm_unlock(info->tm, b); 119 } 120 121 /*----------------------------------------------------------------*/ 122 123 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 } 130 131 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 } 139 140 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 } 156 157 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 } 163 164 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 /*----------------------------------------------------------------*/ 175 176 void init_shadow_spine(struct shadow_spine *s, struct dm_btree_info *info) 177 { 178 s->info = info; 179 s->count = 0; 180 } 181 182 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 } 190 191 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 } 212 213 struct dm_block *shadow_current(struct shadow_spine *s) 214 { 215 BUG_ON(!s->count); 216 217 return s->nodes[s->count - 1]; 218 } 219 220 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 } 226 227 int shadow_has_parent(struct shadow_spine *s) 228 { 229 return s->count >= 2; 230 } 231 232 dm_block_t shadow_root(struct shadow_spine *s) 233 { 234 return s->root; 235 } 236 237 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 } 241 242 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 } 246 247 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 } 255 256 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