LXR linux/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 */
  24struct 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
  34static 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
  41static 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
  48static 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
  56static 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
  64static 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
  71static 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
  86static int sm_disk_set_count(struct dm_space_map *sm, dm_block_t b,
  87                             uint32_t count)
  88{
  89        int r;
  90        uint32_t old_count;
  91        enum allocation_event ev;
  92        struct sm_disk *smd = container_of(sm, struct sm_disk, sm);
  93
  94        r = sm_ll_insert(&smd->ll, b, count, &ev);
  95        if (!r) {
  96                switch (ev) {
  97                case SM_NONE:
  98                        break;
  99
 100                case SM_ALLOC:
 101                        /*
 102                         * This _must_ be free in the prior transaction
 103                         * otherwise we've lost atomicity.
 104                         */
 105                        smd->nr_allocated_this_transaction++;
 106                        break;
 107
 108                case SM_FREE:
 109                        /*
 110                         * It's only free if it's also free in the last
 111                         * transaction.
 112                         */
 113                        r = sm_ll_lookup(&smd->old_ll, b, &old_count);
 114                        if (r)
 115                                return r;
 116
 117                        if (!old_count)
 118                                smd->nr_allocated_this_transaction--;
 119                        break;
 120                }
 121        }
 122
 123        return r;
 124}
 125
 126static int sm_disk_inc_block(struct dm_space_map *sm, dm_block_t b)
 127{
 128        int r;
 129        enum allocation_event ev;
 130        struct sm_disk *smd = container_of(sm, struct sm_disk, sm);
 131
 132        r = sm_ll_inc(&smd->ll, b, &ev);
 133        if (!r && (ev == SM_ALLOC))
 134                /*
 135                 * This _must_ be free in the prior transaction
 136                 * otherwise we've lost atomicity.
 137                 */
 138                smd->nr_allocated_this_transaction++;
 139
 140        return r;
 141}
 142
 143static int sm_disk_dec_block(struct dm_space_map *sm, dm_block_t b)
 144{
 145        enum allocation_event ev;
 146        struct sm_disk *smd = container_of(sm, struct sm_disk, sm);
 147
 148        return sm_ll_dec(&smd->ll, b, &ev);
 149}
 150
 151static int sm_disk_new_block(struct dm_space_map *sm, dm_block_t *b)
 152{
 153        int r;
 154        enum allocation_event ev;
 155        struct sm_disk *smd = container_of(sm, struct sm_disk, sm);
 156
 157        /* FIXME: we should loop round a couple of times */
 158        r = sm_ll_find_free_block(&smd->old_ll, smd->begin, smd->old_ll.nr_blocks, b);
 159        if (r)
 160                return r;
 161
 162        smd->begin = *b + 1;
 163        r = sm_ll_inc(&smd->ll, *b, &ev);
 164        if (!r) {
 165                BUG_ON(ev != SM_ALLOC);
 166                smd->nr_allocated_this_transaction++;
 167        }
 168
 169        return r;
 170}
 171
 172static int sm_disk_commit(struct dm_space_map *sm)
 173{
 174        int r;
 175        dm_block_t nr_free;
 176        struct sm_disk *smd = container_of(sm, struct sm_disk, sm);
 177
 178        r = sm_disk_get_nr_free(sm, &nr_free);
 179        if (r)
 180                return r;
 181
 182        r = sm_ll_commit(&smd->ll);
 183        if (r)
 184                return r;
 185
 186        memcpy(&smd->old_ll, &smd->ll, sizeof(smd->old_ll));
 187        smd->begin = 0;
 188        smd->nr_allocated_this_transaction = 0;
 189
 190        r = sm_disk_get_nr_free(sm, &nr_free);
 191        if (r)
 192                return r;
 193
 194        return 0;
 195}
 196
 197static int sm_disk_root_size(struct dm_space_map *sm, size_t *result)
 198{
 199        *result = sizeof(struct disk_sm_root);
 200
 201        return 0;
 202}
 203
 204static int sm_disk_copy_root(struct dm_space_map *sm, void *where_le, size_t max)
 205{
 206        struct sm_disk *smd = container_of(sm, struct sm_disk, sm);
 207        struct disk_sm_root root_le;
 208
 209        root_le.nr_blocks = cpu_to_le64(smd->ll.nr_blocks);
 210        root_le.nr_allocated = cpu_to_le64(smd->ll.nr_allocated);
 211        root_le.bitmap_root = cpu_to_le64(smd->ll.bitmap_root);
 212        root_le.ref_count_root = cpu_to_le64(smd->ll.ref_count_root);
 213
 214        if (max < sizeof(root_le))
 215                return -ENOSPC;
 216
 217        memcpy(where_le, &root_le, sizeof(root_le));
 218
 219        return 0;
 220}
 221
 222/*----------------------------------------------------------------*/
 223
 224static struct dm_space_map ops = {
 225        .destroy = sm_disk_destroy,
 226        .extend = sm_disk_extend,
 227        .get_nr_blocks = sm_disk_get_nr_blocks,
 228        .get_nr_free = sm_disk_get_nr_free,
 229        .get_count = sm_disk_get_count,
 230        .count_is_more_than_one = sm_disk_count_is_more_than_one,
 231        .set_count = sm_disk_set_count,
 232        .inc_block = sm_disk_inc_block,
 233        .dec_block = sm_disk_dec_block,
 234        .new_block = sm_disk_new_block,
 235        .commit = sm_disk_commit,
 236        .root_size = sm_disk_root_size,
 237        .copy_root = sm_disk_copy_root,
 238        .register_threshold_callback = NULL
 239};
 240
 241struct dm_space_map *dm_sm_disk_create(struct dm_transaction_manager *tm,
 242                                       dm_block_t nr_blocks)
 243{
 244        int r;
 245        struct sm_disk *smd;
 246
 247        smd = kmalloc(sizeof(*smd), GFP_KERNEL);
 248        if (!smd)
 249                return ERR_PTR(-ENOMEM);
 250
 251        smd->begin = 0;
 252        smd->nr_allocated_this_transaction = 0;
 253        memcpy(&smd->sm, &ops, sizeof(smd->sm));
 254
 255        r = sm_ll_new_disk(&smd->ll, tm);
 256        if (r)
 257                goto bad;
 258
 259        r = sm_ll_extend(&smd->ll, nr_blocks);
 260        if (r)
 261                goto bad;
 262
 263        r = sm_disk_commit(&smd->sm);
 264        if (r)
 265                goto bad;
 266
 267        return &smd->sm;
 268
 269bad:
 270        kfree(smd);
 271        return ERR_PTR(r);
 272}
 273EXPORT_SYMBOL_GPL(dm_sm_disk_create);
 274
 275struct dm_space_map *dm_sm_disk_open(struct dm_transaction_manager *tm,
 276                                     void *root_le, size_t len)
 277{
 278        int r;
 279        struct sm_disk *smd;
 280
 281        smd = kmalloc(sizeof(*smd), GFP_KERNEL);
 282        if (!smd)
 283                return ERR_PTR(-ENOMEM);
 284
 285        smd->begin = 0;
 286        smd->nr_allocated_this_transaction = 0;
 287        memcpy(&smd->sm, &ops, sizeof(smd->sm));
 288
 289        r = sm_ll_open_disk(&smd->ll, tm, root_le, len);
 290        if (r)
 291                goto bad;
 292
 293        r = sm_disk_commit(&smd->sm);
 294        if (r)
 295                goto bad;
 296
 297        return &smd->sm;
 298
 299bad:
 300        kfree(smd);
 301        return ERR_PTR(r);
 302}
 303EXPORT_SYMBOL_GPL(dm_sm_disk_open);
 304
 305/*----------------------------------------------------------------*/
 306