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

   1 /* SPDX-License-Identifier: GPL-2.0-only */
   2 /*
   3  * Copyright (C) 2011 Red Hat, Inc.
   4  *
   5  * This file is released under the GPL.
   6  */
   7
   8 #ifndef DM_SPACE_MAP_METADATA_H
   9 #define DM_SPACE_MAP_METADATA_H
  10
  11 #include "dm-transaction-manager.h"
  12
  13 #define DM_SM_METADATA_BLOCK_SIZE (4096 >> SECTOR_SHIFT)
  14
  15 /*
  16  * The metadata device is currently limited in size.
  17  *
  18  * We have one block of index, which can hold 255 index entries.  Each
  19  * index entry contains allocation info about ~16k metadata blocks.
  20  */
  21 #define DM_SM_METADATA_MAX_BLOCKS (255 * ((1 << 14) - 64))
  22 #define DM_SM_METADATA_MAX_SECTORS (DM_SM_METADATA_MAX_BLOCKS * DM_SM_METADATA_BLOCK_SIZE)
  23
  24 /*
  25  * Unfortunately we have to use two-phase construction due to the cycle
  26  * between the tm and sm.
  27  */
  28 struct dm_space_map *dm_sm_metadata_init(void);
  29
  30 /*
  31  * Create a fresh space map.
  32  */
  33 int dm_sm_metadata_create(struct dm_space_map *sm,
  34                           struct dm_transaction_manager *tm,
  35                           dm_block_t nr_blocks,
  36                           dm_block_t superblock);
  37
  38 /*
  39  * Open from a previously-recorded root.
  40  */
  41 int dm_sm_metadata_open(struct dm_space_map *sm,
  42                         struct dm_transaction_manager *tm,
  43                         void *root_le, size_t len);
  44
  45 #endif  /* DM_SPACE_MAP_METADATA_H */