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         *result = count > 1;
  82
  83         return 0;
  84 }
  85
  86 static int sm_disk_set_count(struct dm_space_map *sm, dm_block_t b,
  87                              uint32_t count)
  88 {
  89         int r;
  90         int32_t nr_allocations;
  91         struct sm_disk *smd = container_of(sm, struct sm_disk, sm);
  92
  93         r = sm_ll_insert(&smd->ll, b, count, &nr_allocations);
  94         if (!r) {
  95                 smd->nr_allocated_this_transaction += nr_allocations;
  96         }
  97
  98         return r;
  99 }
 100
 101 static int sm_disk_inc_blocks(struct dm_space_map *sm, dm_block_t b, dm_block_t e)
 102 {
 103         int r;
 104         int32_t nr_allocations;
 105         struct sm_disk *smd = container_of(sm, struct sm_disk, sm);
 106
 107         r = sm_ll_inc(&smd->ll, b, e, &nr_allocations);
 108         if (!r)
 109                 smd->nr_allocated_this_transaction += nr_allocations;
 110
 111         return r;
 112 }
 113
 114 static int sm_disk_dec_blocks(struct dm_space_map *sm, dm_block_t b, dm_block_t e)
 115 {
 116         int r;
 117         int32_t nr_allocations;
 118         struct sm_disk *smd = container_of(sm, struct sm_disk, sm);
 119
 120         r = sm_ll_dec(&smd->ll, b, e, &nr_allocations);
 121         if (!r)
 122                 smd->nr_allocated_this_transaction += nr_allocations;
 123
 124         return r;
 125 }
 126
 127 static int sm_disk_new_block(struct dm_space_map *sm, dm_block_t *b)
 128 {
 129         int r;
 130         int32_t nr_allocations;
 131         struct sm_disk *smd = container_of(sm, struct sm_disk, sm);
 132
 133         /*
 134          * Any block we allocate has to be free in both the old and current ll.
 135          */
 136         r = sm_ll_find_common_free_block(&smd->old_ll, &smd->ll, smd->begin, smd->ll.nr_blocks, b);
 137         if (r == -ENOSPC) {
 138                 /*
 139                  * There's no free block between smd->begin and the end of the metadata device.
 140                  * We search before smd->begin in case something has been freed.
 141                  */
 142                 r = sm_ll_find_common_free_block(&smd->old_ll, &smd->ll, 0, smd->begin, b);
 143         }
 144
 145         if (r)
 146                 return r;
 147
 148         smd->begin = *b + 1;
 149         r = sm_ll_inc(&smd->ll, *b, *b + 1, &nr_allocations);
 150         if (!r) {
 151                 smd->nr_allocated_this_transaction += nr_allocations;
 152         }
 153
 154         return r;
 155 }
 156
 157 static int sm_disk_commit(struct dm_space_map *sm)
 158 {
 159         int r;
 160         struct sm_disk *smd = container_of(sm, struct sm_disk, sm);
 161
 162         r = sm_ll_commit(&smd->ll);
 163         if (r)
 164                 return r;
 165
 166         memcpy(&smd->old_ll, &smd->ll, sizeof(smd->old_ll));
 167         smd->nr_allocated_this_transaction = 0;
 168
 169         return 0;
 170 }
 171
 172 static int sm_disk_root_size(struct dm_space_map *sm, size_t *result)
 173 {
 174         *result = sizeof(struct disk_sm_root);
 175
 176         return 0;
 177 }
 178
 179 static int sm_disk_copy_root(struct dm_space_map *sm, void *where_le, size_t max)
 180 {
 181         struct sm_disk *smd = container_of(sm, struct sm_disk, sm);
 182         struct disk_sm_root root_le;
 183
 184         root_le.nr_blocks = cpu_to_le64(smd->ll.nr_blocks);
 185         root_le.nr_allocated = cpu_to_le64(smd->ll.nr_allocated);
 186         root_le.bitmap_root = cpu_to_le64(smd->ll.bitmap_root);
 187         root_le.ref_count_root = cpu_to_le64(smd->ll.ref_count_root);
 188
 189         if (max < sizeof(root_le))
 190                 return -ENOSPC;
 191
 192         memcpy(where_le, &root_le, sizeof(root_le));
 193
 194         return 0;
 195 }
 196
 197 /*----------------------------------------------------------------*/
 198
 199 static struct dm_space_map ops = {
 200         .destroy = sm_disk_destroy,
 201         .extend = sm_disk_extend,
 202         .get_nr_blocks = sm_disk_get_nr_blocks,
 203         .get_nr_free = sm_disk_get_nr_free,
 204         .get_count = sm_disk_get_count,
 205         .count_is_more_than_one = sm_disk_count_is_more_than_one,
 206         .set_count = sm_disk_set_count,
 207         .inc_blocks = sm_disk_inc_blocks,
 208         .dec_blocks = sm_disk_dec_blocks,
 209         .new_block = sm_disk_new_block,
 210         .commit = sm_disk_commit,
 211         .root_size = sm_disk_root_size,
 212         .copy_root = sm_disk_copy_root,
 213         .register_threshold_callback = NULL
 214 };
 215
 216 struct dm_space_map *dm_sm_disk_create(struct dm_transaction_manager *tm,
 217                                        dm_block_t nr_blocks)
 218 {
 219         int r;
 220         struct sm_disk *smd;
 221
 222         smd = kmalloc(sizeof(*smd), GFP_KERNEL);
 223         if (!smd)
 224                 return ERR_PTR(-ENOMEM);
 225
 226         smd->begin = 0;
 227         smd->nr_allocated_this_transaction = 0;
 228         memcpy(&smd->sm, &ops, sizeof(smd->sm));
 229
 230         r = sm_ll_new_disk(&smd->ll, tm);
 231         if (r)
 232                 goto bad;
 233
 234         r = sm_ll_extend(&smd->ll, nr_blocks);
 235         if (r)
 236                 goto bad;
 237
 238         r = sm_disk_commit(&smd->sm);
 239         if (r)
 240                 goto bad;
 241
 242         return &smd->sm;
 243
 244 bad:
 245         kfree(smd);
 246         return ERR_PTR(r);
 247 }
 248 EXPORT_SYMBOL_GPL(dm_sm_disk_create);
 249
 250 struct dm_space_map *dm_sm_disk_open(struct dm_transaction_manager *tm,
 251                                      void *root_le, size_t len)
 252 {
 253         int r;
 254         struct sm_disk *smd;
 255
 256         smd = kmalloc(sizeof(*smd), GFP_KERNEL);
 257         if (!smd)
 258                 return ERR_PTR(-ENOMEM);
 259
 260         smd->begin = 0;
 261         smd->nr_allocated_this_transaction = 0;
 262         memcpy(&smd->sm, &ops, sizeof(smd->sm));
 263
 264         r = sm_ll_open_disk(&smd->ll, tm, root_le, len);
 265         if (r)
 266                 goto bad;
 267
 268         r = sm_disk_commit(&smd->sm);
 269         if (r)
 270                 goto bad;
 271
 272         return &smd->sm;
 273
 274 bad:
 275         kfree(smd);
 276         return ERR_PTR(r);
 277 }
 278 EXPORT_SYMBOL_GPL(dm_sm_disk_open);
 279
 280 /*----------------------------------------------------------------*/