drivers/md/persistent-data/dm-btree-spine.c

   1 /*
   2  * Copyright (C) 2011 Red Hat, Inc. All rights reserved.
   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 static void node_prepare_for_write(struct dm_block_validator *v,
  17                                    struct dm_block *b,
  18                                    size_t block_size)
  19 {
  20         struct node *n = dm_block_data(b);
  21         struct node_header *h = &n->header;
  22
  23         h->blocknr = cpu_to_le64(dm_block_location(b));
  24         h->csum = cpu_to_le32(dm_block_csum_data(&h->flags, block_size - sizeof(__le32)));
  25 }
  26
  27 static int node_check(struct dm_block_validator *v,
  28                       struct dm_block *b,
  29                       size_t block_size)
  30 {
  31         struct node *n = dm_block_data(b);
  32         struct node_header *h = &n->header;
  33         size_t value_size;
  34         __le32 csum_disk;
  35
  36         if (dm_block_location(b) != le64_to_cpu(h->blocknr)) {
  37                 DMERR("node_check failed blocknr %llu wanted %llu",
  38                       le64_to_cpu(h->blocknr), dm_block_location(b));
  39                 return -ENOTBLK;
  40         }
  41
  42         csum_disk = cpu_to_le32(dm_block_csum_data(&h->flags, block_size - sizeof(__le32)));
  43         if (csum_disk != h->csum) {
  44                 DMERR("node_check failed csum %u wanted %u",
  45                       le32_to_cpu(csum_disk), le32_to_cpu(h->csum));
  46                 return -EILSEQ;
  47         }
  48
  49         value_size = le32_to_cpu(h->value_size);
  50
  51         if (sizeof(struct node_header) +
  52             (sizeof(__le64) + value_size) * le32_to_cpu(h->max_entries) > block_size) {
  53                 DMERR("node_check failed: max_entries too large");
  54                 return -EILSEQ;
  55         }
  56
  57         if (le32_to_cpu(h->nr_entries) > le32_to_cpu(h->max_entries)) {
  58                 DMERR("node_check failed, too many entries");
  59                 return -EILSEQ;
  60         }
  61
  62         return 0;
  63 }
  64
  65 struct dm_block_validator btree_node_validator = {
  66         .name = "btree_node",
  67         .prepare_for_write = node_prepare_for_write,
  68         .check = node_check
  69 };
  70
  71 /*----------------------------------------------------------------*/
  72
  73 static int bn_read_lock(struct dm_btree_info *info, dm_block_t b,
  74                  struct dm_block **result)
  75 {
  76         return dm_tm_read_lock(info->tm, b, &btree_node_validator, result);
  77 }
  78
  79 static int bn_shadow(struct dm_btree_info *info, dm_block_t orig,
  80               struct dm_btree_value_type *vt,
  81               struct dm_block **result, int *inc)
  82 {
  83         int r;
  84
  85         r = dm_tm_shadow_block(info->tm, orig, &btree_node_validator,
  86                                result, inc);
  87         if (!r && *inc)
  88                 inc_children(info->tm, dm_block_data(*result), vt);
  89
  90         return r;
  91 }
  92
  93 int new_block(struct dm_btree_info *info, struct dm_block **result)
  94 {
  95         return dm_tm_new_block(info->tm, &btree_node_validator, result);
  96 }
  97
  98 int unlock_block(struct dm_btree_info *info, struct dm_block *b)
  99 {
 100         return dm_tm_unlock(info->tm, b);
 101 }
 102
 103 /*----------------------------------------------------------------*/
 104
 105 void init_ro_spine(struct ro_spine *s, struct dm_btree_info *info)
 106 {
 107         s->info = info;
 108         s->count = 0;
 109         s->nodes[0] = NULL;
 110         s->nodes[1] = NULL;
 111 }
 112
 113 int exit_ro_spine(struct ro_spine *s)
 114 {
 115         int r = 0, i;
 116
 117         for (i = 0; i < s->count; i++) {
 118                 int r2 = unlock_block(s->info, s->nodes[i]);
 119                 if (r2 < 0)
 120                         r = r2;
 121         }
 122
 123         return r;
 124 }
 125
 126 int ro_step(struct ro_spine *s, dm_block_t new_child)
 127 {
 128         int r;
 129
 130         if (s->count == 2) {
 131                 r = unlock_block(s->info, s->nodes[0]);
 132                 if (r < 0)
 133                         return r;
 134                 s->nodes[0] = s->nodes[1];
 135                 s->count--;
 136         }
 137
 138         r = bn_read_lock(s->info, new_child, s->nodes + s->count);
 139         if (!r)
 140                 s->count++;
 141
 142         return r;
 143 }
 144
 145 struct node *ro_node(struct ro_spine *s)
 146 {
 147         struct dm_block *block;
 148
 149         BUG_ON(!s->count);
 150         block = s->nodes[s->count - 1];
 151
 152         return dm_block_data(block);
 153 }
 154
 155 /*----------------------------------------------------------------*/
 156
 157 void init_shadow_spine(struct shadow_spine *s, struct dm_btree_info *info)
 158 {
 159         s->info = info;
 160         s->count = 0;
 161 }
 162
 163 int exit_shadow_spine(struct shadow_spine *s)
 164 {
 165         int r = 0, i;
 166
 167         for (i = 0; i < s->count; i++) {
 168                 int r2 = unlock_block(s->info, s->nodes[i]);
 169                 if (r2 < 0)
 170                         r = r2;
 171         }
 172
 173         return r;
 174 }
 175
 176 int shadow_step(struct shadow_spine *s, dm_block_t b,
 177                 struct dm_btree_value_type *vt, int *inc)
 178 {
 179         int r;
 180
 181         if (s->count == 2) {
 182                 r = unlock_block(s->info, s->nodes[0]);
 183                 if (r < 0)
 184                         return r;
 185                 s->nodes[0] = s->nodes[1];
 186                 s->count--;
 187         }
 188
 189         r = bn_shadow(s->info, b, vt, s->nodes + s->count, inc);
 190         if (!r) {
 191                 if (!s->count)
 192                         s->root = dm_block_location(s->nodes[0]);
 193
 194                 s->count++;
 195         }
 196
 197         return r;
 198 }
 199
 200 struct dm_block *shadow_current(struct shadow_spine *s)
 201 {
 202         BUG_ON(!s->count);
 203
 204         return s->nodes[s->count - 1];
 205 }
 206
 207 struct dm_block *shadow_parent(struct shadow_spine *s)
 208 {
 209         BUG_ON(s->count != 2);
 210
 211         return s->count == 2 ? s->nodes[0] : NULL;
 212 }
 213
 214 int shadow_has_parent(struct shadow_spine *s)
 215 {
 216         return s->count >= 2;
 217 }
 218
 219 int shadow_root(struct shadow_spine *s)
 220 {
 221         return s->root;
 222 }