LXR linux/drivers/md/persistent-data/dm-space-map-metadata.h

   1/*
   2 * Copyright (C) 2011 Red Hat, Inc.
   3 *
   4 * This file is released under the GPL.
   5 */
   6
   7#ifndef DM_SPACE_MAP_METADATA_H
   8#define DM_SPACE_MAP_METADATA_H
   9
  10#include "dm-transaction-manager.h"
  11
  12#define DM_SM_METADATA_BLOCK_SIZE (4096 >> SECTOR_SHIFT)
  13
  14/*
  15 * The metadata device is currently limited in size.
  16 *
  17 * We have one block of index, which can hold 255 index entries.  Each
  18 * index entry contains allocation info about ~16k metadata blocks.
  19 */
  20#define DM_SM_METADATA_MAX_BLOCKS (255 * ((1 << 14) - 64))
  21#define DM_SM_METADATA_MAX_SECTORS (DM_SM_METADATA_MAX_BLOCKS * DM_SM_METADATA_BLOCK_SIZE)
  22
  23/*
  24 * Unfortunately we have to use two-phase construction due to the cycle
  25 * between the tm and sm.
  26 */
  27struct dm_space_map *dm_sm_metadata_init(void);
  28
  29/*
  30 * Create a fresh space map.
  31 */
  32int dm_sm_metadata_create(struct dm_space_map *sm,
  33                          struct dm_transaction_manager *tm,
  34                          dm_block_t nr_blocks,
  35                          dm_block_t superblock);
  36
  37/*
  38 * Open from a previously-recorded root.
  39 */
  40int dm_sm_metadata_open(struct dm_space_map *sm,
  41                        struct dm_transaction_manager *tm,
  42                        void *root_le, size_t len);
  43
  44#endif  /* DM_SPACE_MAP_METADATA_H */
  45