LXR linux/drivers/md/persistent-data/dm-space-map-common.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_COMMON_H
   8#define DM_SPACE_MAP_COMMON_H
   9
  10#include "dm-btree.h"
  11
  12/*----------------------------------------------------------------*/
  13
  14/*
  15 * Low level disk format
  16 *
  17 * Bitmap btree
  18 * ------------
  19 *
  20 * Each value stored in the btree is an index_entry.  This points to a
  21 * block that is used as a bitmap.  Within the bitmap hold 2 bits per
  22 * entry, which represent UNUSED = 0, REF_COUNT = 1, REF_COUNT = 2 and
  23 * REF_COUNT = many.
  24 *
  25 * Refcount btree
  26 * --------------
  27 *
  28 * Any entry that has a ref count higher than 2 gets entered in the ref
  29 * count tree.  The leaf values for this tree is the 32-bit ref count.
  30 */
  31
  32struct disk_index_entry {
  33        __le64 blocknr;
  34        __le32 nr_free;
  35        __le32 none_free_before;
  36} __packed;
  37
  38
  39#define MAX_METADATA_BITMAPS 255
  40struct disk_metadata_index {
  41        __le32 csum;
  42        __le32 padding;
  43        __le64 blocknr;
  44
  45        struct disk_index_entry index[MAX_METADATA_BITMAPS];
  46} __packed;
  47
  48struct ll_disk;
  49
  50typedef int (*load_ie_fn)(struct ll_disk *ll, dm_block_t index, struct disk_index_entry *result);
  51typedef int (*save_ie_fn)(struct ll_disk *ll, dm_block_t index, struct disk_index_entry *ie);
  52typedef int (*init_index_fn)(struct ll_disk *ll);
  53typedef int (*open_index_fn)(struct ll_disk *ll);
  54typedef dm_block_t (*max_index_entries_fn)(struct ll_disk *ll);
  55typedef int (*commit_fn)(struct ll_disk *ll);
  56
  57struct ll_disk {
  58        struct dm_transaction_manager *tm;
  59        struct dm_btree_info bitmap_info;
  60        struct dm_btree_info ref_count_info;
  61
  62        uint32_t block_size;
  63        uint32_t entries_per_block;
  64        dm_block_t nr_blocks;
  65        dm_block_t nr_allocated;
  66
  67        /*
  68         * bitmap_root may be a btree root or a simple index.
  69         */
  70        dm_block_t bitmap_root;
  71
  72        dm_block_t ref_count_root;
  73
  74        struct disk_metadata_index mi_le;
  75        load_ie_fn load_ie;
  76        save_ie_fn save_ie;
  77        init_index_fn init_index;
  78        open_index_fn open_index;
  79        max_index_entries_fn max_entries;
  80        commit_fn commit;
  81        bool bitmap_index_changed:1;
  82};
  83
  84struct disk_sm_root {
  85        __le64 nr_blocks;
  86        __le64 nr_allocated;
  87        __le64 bitmap_root;
  88        __le64 ref_count_root;
  89} __packed;
  90
  91#define ENTRIES_PER_BYTE 4
  92
  93struct disk_bitmap_header {
  94        __le32 csum;
  95        __le32 not_used;
  96        __le64 blocknr;
  97} __packed;
  98
  99enum allocation_event {
 100        SM_NONE,
 101        SM_ALLOC,
 102        SM_FREE,
 103};
 104
 105/*----------------------------------------------------------------*/
 106
 107int sm_ll_extend(struct ll_disk *ll, dm_block_t extra_blocks);
 108int sm_ll_lookup_bitmap(struct ll_disk *ll, dm_block_t b, uint32_t *result);
 109int sm_ll_lookup(struct ll_disk *ll, dm_block_t b, uint32_t *result);
 110int sm_ll_find_free_block(struct ll_disk *ll, dm_block_t begin,
 111                          dm_block_t end, dm_block_t *result);
 112int sm_ll_insert(struct ll_disk *ll, dm_block_t b, uint32_t ref_count, enum allocation_event *ev);
 113int sm_ll_inc(struct ll_disk *ll, dm_block_t b, enum allocation_event *ev);
 114int sm_ll_dec(struct ll_disk *ll, dm_block_t b, enum allocation_event *ev);
 115int sm_ll_commit(struct ll_disk *ll);
 116
 117int sm_ll_new_metadata(struct ll_disk *ll, struct dm_transaction_manager *tm);
 118int sm_ll_open_metadata(struct ll_disk *ll, struct dm_transaction_manager *tm,
 119                        void *root_le, size_t len);
 120
 121int sm_ll_new_disk(struct ll_disk *ll, struct dm_transaction_manager *tm);
 122int sm_ll_open_disk(struct ll_disk *ll, struct dm_transaction_manager *tm,
 123                    void *root_le, size_t len);
 124
 125/*----------------------------------------------------------------*/
 126
 127#endif  /* DM_SPACE_MAP_COMMON_H */
 128