drivers/md/persistent-data/dm-space-map-disk.c

   1 /*
   2  * Copyright (C) 2011 Red Hat, Inc.
   3  *
   4  * This file is released under the GPL.
   5  */
   6
   7 #include "dm-space-map-checker.h"
   8 #include "dm-space-map-common.h"
   9 #include "dm-space-map-disk.h"
  10 #include "dm-space-map.h"
  11 #include "dm-transaction-manager.h"
  12
  13 #include <linux/list.h>
  14 #include <linux/slab.h>
  15 #include <linux/module.h>
  16 #include <linux/device-mapper.h>
  17
  18 #define DM_MSG_PREFIX "space map disk"
  19
  20 /*----------------------------------------------------------------*/
  21
  22 /*
  23  * Space map interface.
  24  */
  25 struct sm_disk {
  26         struct dm_space_map sm;
  27
  28         struct ll_disk ll;
  29         struct ll_disk old_ll;
  30
  31         dm_block_t begin;
  32         dm_block_t nr_allocated_this_transaction;
  33 };
  34
  35 static void sm_disk_destroy(struct dm_space_map *sm)
  36 {
  37         struct sm_disk *smd = container_of(sm, struct sm_disk, sm);
  38
  39         kfree(smd);
  40 }
  41
  42 static int sm_disk_extend(struct dm_space_map *sm, dm_block_t extra_blocks)
  43 {
  44         struct sm_disk *smd = container_of(sm, struct sm_disk, sm);
  45
  46         return sm_ll_extend(&smd->ll, extra_blocks);
  47 }
  48
  49 static int sm_disk_get_nr_blocks(struct dm_space_map *sm, dm_block_t *count)
  50 {
  51         struct sm_disk *smd = container_of(sm, struct sm_disk, sm);
  52         *count = smd->old_ll.nr_blocks;
  53
  54         return 0;
  55 }
  56
  57 static int sm_disk_get_nr_free(struct dm_space_map *sm, dm_block_t *count)
  58 {
  59         struct sm_disk *smd = container_of(sm, struct sm_disk, sm);
  60         *count = (smd->old_ll.nr_blocks - smd->old_ll.nr_allocated) - smd->nr_allocated_this_transaction;
  61
  62         return 0;
  63 }
  64
  65 static int sm_disk_get_count(struct dm_space_map *sm, dm_block_t b,
  66                              uint32_t *result)
  67 {
  68         struct sm_disk *smd = container_of(sm, struct sm_disk, sm);
  69         return sm_ll_lookup(&smd->ll, b, result);
  70 }
  71
  72 static int sm_disk_count_is_more_than_one(struct dm_space_map *sm, dm_block_t b,
  73                                           int *result)
  74 {
  75         int r;
  76         uint32_t count;
  77
  78         r = sm_disk_get_count(sm, b, &count);
  79         if (r)
  80                 return r;
  81
  82         return count > 1;
  83 }
  84
  85 static int sm_disk_set_count(struct dm_space_map *sm, dm_block_t b,
  86                              uint32_t count)
  87 {
  88         int r;
  89         uint32_t old_count;
  90         enum allocation_event ev;
  91         struct sm_disk *smd = container_of(sm, struct sm_disk, sm);
  92
  93         r = sm_ll_insert(&smd->ll, b, count, &ev);
  94         if (!r) {
  95                 switch (ev) {
  96                 case SM_NONE:
  97                         break;
  98
  99                 case SM_ALLOC:
 100                         /*
 101                          * This _must_ be free in the prior transaction
 102                          * otherwise we've lost atomicity.
 103                          */
 104                         smd->nr_allocated_this_transaction++;
 105                         break;
 106
 107                 case SM_FREE:
 108                         /*
 109                          * It's only free if it's also free in the last
 110                          * transaction.
 111                          */
 112                         r = sm_ll_lookup(&smd->old_ll, b, &old_count);
 113                         if (r)
 114                                 return r;
 115
 116                         if (!old_count)
 117                                 smd->nr_allocated_this_transaction--;
 118                         break;
 119                 }
 120         }
 121
 122         return r;
 123 }
 124
 125 static int sm_disk_inc_block(struct dm_space_map *sm, dm_block_t b)
 126 {
 127         int r;
 128         enum allocation_event ev;
 129         struct sm_disk *smd = container_of(sm, struct sm_disk, sm);
 130
 131         r = sm_ll_inc(&smd->ll, b, &ev);
 132         if (!r && (ev == SM_ALLOC))
 133                 /*
 134                  * This _must_ be free in the prior transaction
 135                  * otherwise we've lost atomicity.
 136                  */
 137                 smd->nr_allocated_this_transaction++;
 138
 139         return r;
 140 }
 141
 142 static int sm_disk_dec_block(struct dm_space_map *sm, dm_block_t b)
 143 {
 144         int r;
 145         uint32_t old_count;
 146         enum allocation_event ev;
 147         struct sm_disk *smd = container_of(sm, struct sm_disk, sm);
 148
 149         r = sm_ll_dec(&smd->ll, b, &ev);
 150         if (!r && (ev == SM_FREE)) {
 151                 /*
 152                  * It's only free if it's also free in the last
 153                  * transaction.
 154                  */
 155                 r = sm_ll_lookup(&smd->old_ll, b, &old_count);
 156                 if (r)
 157                         return r;
 158
 159                 if (!old_count)
 160                         smd->nr_allocated_this_transaction--;
 161         }
 162
 163         return r;
 164 }
 165
 166 static int sm_disk_new_block(struct dm_space_map *sm, dm_block_t *b)
 167 {
 168         int r;
 169         enum allocation_event ev;
 170         struct sm_disk *smd = container_of(sm, struct sm_disk, sm);
 171
 172         /* FIXME: we should loop round a couple of times */
 173         r = sm_ll_find_free_block(&smd->old_ll, smd->begin, smd->old_ll.nr_blocks, b);
 174         if (r)
 175                 return r;
 176
 177         smd->begin = *b + 1;
 178         r = sm_ll_inc(&smd->ll, *b, &ev);
 179         if (!r) {
 180                 BUG_ON(ev != SM_ALLOC);
 181                 smd->nr_allocated_this_transaction++;
 182         }
 183
 184         return r;
 185 }
 186
 187 static int sm_disk_commit(struct dm_space_map *sm)
 188 {
 189         int r;
 190         dm_block_t nr_free;
 191         struct sm_disk *smd = container_of(sm, struct sm_disk, sm);
 192
 193         r = sm_disk_get_nr_free(sm, &nr_free);
 194         if (r)
 195                 return r;
 196
 197         r = sm_ll_commit(&smd->ll);
 198         if (r)
 199                 return r;
 200
 201         memcpy(&smd->old_ll, &smd->ll, sizeof(smd->old_ll));
 202         smd->begin = 0;
 203         smd->nr_allocated_this_transaction = 0;
 204
 205         r = sm_disk_get_nr_free(sm, &nr_free);
 206         if (r)
 207                 return r;
 208
 209         return 0;
 210 }
 211
 212 static int sm_disk_root_size(struct dm_space_map *sm, size_t *result)
 213 {
 214         *result = sizeof(struct disk_sm_root);
 215
 216         return 0;
 217 }
 218
 219 static int sm_disk_copy_root(struct dm_space_map *sm, void *where_le, size_t max)
 220 {
 221         struct sm_disk *smd = container_of(sm, struct sm_disk, sm);
 222         struct disk_sm_root root_le;
 223
 224         root_le.nr_blocks = cpu_to_le64(smd->ll.nr_blocks);
 225         root_le.nr_allocated = cpu_to_le64(smd->ll.nr_allocated);
 226         root_le.bitmap_root = cpu_to_le64(smd->ll.bitmap_root);
 227         root_le.ref_count_root = cpu_to_le64(smd->ll.ref_count_root);
 228
 229         if (max < sizeof(root_le))
 230                 return -ENOSPC;
 231
 232         memcpy(where_le, &root_le, sizeof(root_le));
 233
 234         return 0;
 235 }
 236
 237 /*----------------------------------------------------------------*/
 238
 239 static struct dm_space_map ops = {
 240         .destroy = sm_disk_destroy,
 241         .extend = sm_disk_extend,
 242         .get_nr_blocks = sm_disk_get_nr_blocks,
 243         .get_nr_free = sm_disk_get_nr_free,
 244         .get_count = sm_disk_get_count,
 245         .count_is_more_than_one = sm_disk_count_is_more_than_one,
 246         .set_count = sm_disk_set_count,
 247         .inc_block = sm_disk_inc_block,
 248         .dec_block = sm_disk_dec_block,
 249         .new_block = sm_disk_new_block,
 250         .commit = sm_disk_commit,
 251         .root_size = sm_disk_root_size,
 252         .copy_root = sm_disk_copy_root
 253 };
 254
 255 static struct dm_space_map *dm_sm_disk_create_real(
 256         struct dm_transaction_manager *tm,
 257         dm_block_t nr_blocks)
 258 {
 259         int r;
 260         struct sm_disk *smd;
 261
 262         smd = kmalloc(sizeof(*smd), GFP_KERNEL);
 263         if (!smd)
 264                 return ERR_PTR(-ENOMEM);
 265
 266         smd->begin = 0;
 267         smd->nr_allocated_this_transaction = 0;
 268         memcpy(&smd->sm, &ops, sizeof(smd->sm));
 269
 270         r = sm_ll_new_disk(&smd->ll, tm);
 271         if (r)
 272                 goto bad;
 273
 274         r = sm_ll_extend(&smd->ll, nr_blocks);
 275         if (r)
 276                 goto bad;
 277
 278         r = sm_disk_commit(&smd->sm);
 279         if (r)
 280                 goto bad;
 281
 282         return &smd->sm;
 283
 284 bad:
 285         kfree(smd);
 286         return ERR_PTR(r);
 287 }
 288
 289 struct dm_space_map *dm_sm_disk_create(struct dm_transaction_manager *tm,
 290                                        dm_block_t nr_blocks)
 291 {
 292         struct dm_space_map *sm = dm_sm_disk_create_real(tm, nr_blocks);
 293         return dm_sm_checker_create_fresh(sm);
 294 }
 295 EXPORT_SYMBOL_GPL(dm_sm_disk_create);
 296
 297 static struct dm_space_map *dm_sm_disk_open_real(
 298         struct dm_transaction_manager *tm,
 299         void *root_le, size_t len)
 300 {
 301         int r;
 302         struct sm_disk *smd;
 303
 304         smd = kmalloc(sizeof(*smd), GFP_KERNEL);
 305         if (!smd)
 306                 return ERR_PTR(-ENOMEM);
 307
 308         smd->begin = 0;
 309         smd->nr_allocated_this_transaction = 0;
 310         memcpy(&smd->sm, &ops, sizeof(smd->sm));
 311
 312         r = sm_ll_open_disk(&smd->ll, tm, root_le, len);
 313         if (r)
 314                 goto bad;
 315
 316         r = sm_disk_commit(&smd->sm);
 317         if (r)
 318                 goto bad;
 319
 320         return &smd->sm;
 321
 322 bad:
 323         kfree(smd);
 324         return ERR_PTR(r);
 325 }
 326
 327 struct dm_space_map *dm_sm_disk_open(struct dm_transaction_manager *tm,
 328                                      void *root_le, size_t len)
 329 {
 330         return dm_sm_checker_create(
 331                 dm_sm_disk_open_real(tm, root_le, len));
 332 }
 333 EXPORT_SYMBOL_GPL(dm_sm_disk_open);
 334
 335 /*----------------------------------------------------------------*/