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