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
  32 struct 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
  40 struct 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
  48 struct ll_disk;
  49
  50 typedef int (*load_ie_fn)(struct ll_disk *ll, dm_block_t index, struct disk_index_entry *result);
  51 typedef int (*save_ie_fn)(struct ll_disk *ll, dm_block_t index, struct disk_index_entry *ie);
  52 typedef int (*init_index_fn)(struct ll_disk *ll);
  53 typedef int (*open_index_fn)(struct ll_disk *ll);
  54 typedef dm_block_t (*max_index_entries_fn)(struct ll_disk *ll);
  55 typedef int (*commit_fn)(struct ll_disk *ll);
  56
  57 struct 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
  84 struct 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
  93 struct disk_bitmap_header {
  94         __le32 csum;
  95         __le32 not_used;
  96         __le64 blocknr;
  97 } __packed;
  98
  99 enum allocation_event {
 100         SM_NONE,
 101         SM_ALLOC,
 102         SM_FREE,
 103 };
 104
 105 /*----------------------------------------------------------------*/
 106
 107 int sm_ll_extend(struct ll_disk *ll, dm_block_t extra_blocks);
 108 int sm_ll_lookup_bitmap(struct ll_disk *ll, dm_block_t b, uint32_t *result);
 109 int sm_ll_lookup(struct ll_disk *ll, dm_block_t b, uint32_t *result);
 110 int sm_ll_find_free_block(struct ll_disk *ll, dm_block_t begin,
 111                           dm_block_t end, dm_block_t *result);
 112 int sm_ll_insert(struct ll_disk *ll, dm_block_t b, uint32_t ref_count, enum allocation_event *ev);
 113 int sm_ll_inc(struct ll_disk *ll, dm_block_t b, enum allocation_event *ev);
 114 int sm_ll_dec(struct ll_disk *ll, dm_block_t b, enum allocation_event *ev);
 115 int sm_ll_commit(struct ll_disk *ll);
 116
 117 int sm_ll_new_metadata(struct ll_disk *ll, struct dm_transaction_manager *tm);
 118 int sm_ll_open_metadata(struct ll_disk *ll, struct dm_transaction_manager *tm,
 119                         void *root_le, size_t len);
 120
 121 int sm_ll_new_disk(struct ll_disk *ll, struct dm_transaction_manager *tm);
 122 int 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 */