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 18static int node_check(struct dm_block_validator *v, 19 struct dm_block *b, 20 size_t block_size); 21 22static 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 37static 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 87struct 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 95int 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 101static 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 115int 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 120int unlock_block(struct dm_btree_info *info, struct dm_block *b) 121{ 122 return dm_tm_unlock(info->tm, b); 123} 124 125/*----------------------------------------------------------------*/ 126 127void 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 135int exit_ro_spine(struct ro_spine *s) 136{ 137 int r = 0, i; 138 139 for (i = 0; i < s->count; i++) { 140 int r2 = unlock_block(s->info, s->nodes[i]); 141 if (r2 < 0) 142 r = r2; 143 } 144 145 return r; 146} 147 148int ro_step(struct ro_spine *s, dm_block_t new_child) 149{ 150 int r; 151 152 if (s->count == 2) { 153 r = unlock_block(s->info, s->nodes[0]); 154 if (r < 0) 155 return r; 156 s->nodes[0] = s->nodes[1]; 157 s->count--; 158 } 159 160 r = bn_read_lock(s->info, new_child, s->nodes + s->count); 161 if (!r) 162 s->count++; 163 164 return r; 165} 166 167void ro_pop(struct ro_spine *s) 168{ 169 BUG_ON(!s->count); 170 --s->count; 171 unlock_block(s->info, s->nodes[s->count]); 172} 173 174struct btree_node *ro_node(struct ro_spine *s) 175{ 176 struct dm_block *block; 177 178 BUG_ON(!s->count); 179 block = s->nodes[s->count - 1]; 180 181 return dm_block_data(block); 182} 183 184/*----------------------------------------------------------------*/ 185 186void init_shadow_spine(struct shadow_spine *s, struct dm_btree_info *info) 187{ 188 s->info = info; 189 s->count = 0; 190} 191 192int exit_shadow_spine(struct shadow_spine *s) 193{ 194 int r = 0, i; 195 196 for (i = 0; i < s->count; i++) { 197 int r2 = unlock_block(s->info, s->nodes[i]); 198 if (r2 < 0) 199 r = r2; 200 } 201 202 return r; 203} 204 205int shadow_step(struct shadow_spine *s, dm_block_t b, 206 struct dm_btree_value_type *vt) 207{ 208 int r; 209 210 if (s->count == 2) { 211 r = unlock_block(s->info, s->nodes[0]); 212 if (r < 0) 213 return r; 214 s->nodes[0] = s->nodes[1]; 215 s->count--; 216 } 217 218 r = bn_shadow(s->info, b, vt, s->nodes + s->count); 219 if (!r) { 220 if (!s->count) 221 s->root = dm_block_location(s->nodes[0]); 222 223 s->count++; 224 } 225 226 return r; 227} 228 229struct dm_block *shadow_current(struct shadow_spine *s) 230{ 231 BUG_ON(!s->count); 232 233 return s->nodes[s->count - 1]; 234} 235 236struct dm_block *shadow_parent(struct shadow_spine *s) 237{ 238 BUG_ON(s->count != 2); 239 240 return s->count == 2 ? s->nodes[0] : NULL; 241} 242 243int shadow_has_parent(struct shadow_spine *s) 244{ 245 return s->count >= 2; 246} 247 248int shadow_root(struct shadow_spine *s) 249{ 250 return s->root; 251} 252 253static void le64_inc(void *context, const void *value_le) 254{ 255 struct dm_transaction_manager *tm = context; 256 __le64 v_le; 257 258 memcpy(&v_le, value_le, sizeof(v_le)); 259 dm_tm_inc(tm, le64_to_cpu(v_le)); 260} 261 262static void le64_dec(void *context, const void *value_le) 263{ 264 struct dm_transaction_manager *tm = context; 265 __le64 v_le; 266 267 memcpy(&v_le, value_le, sizeof(v_le)); 268 dm_tm_dec(tm, le64_to_cpu(v_le)); 269} 270 271static int le64_equal(void *context, const void *value1_le, const void *value2_le) 272{ 273 __le64 v1_le, v2_le; 274 275 memcpy(&v1_le, value1_le, sizeof(v1_le)); 276 memcpy(&v2_le, value2_le, sizeof(v2_le)); 277 return v1_le == v2_le; 278} 279 280void init_le64_type(struct dm_transaction_manager *tm, 281 struct dm_btree_value_type *vt) 282{ 283 vt->context = tm; 284 vt->size = sizeof(__le64); 285 vt->inc = le64_inc; 286 vt->dec = le64_dec; 287 vt->equal = le64_equal; 288} 289