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  */
  27 struct dm_space_map *dm_sm_metadata_init(void);
  28
  29 /*
  30  * Create a fresh space map.
  31  */
  32 int 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  */
  40 int 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 */