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

   1 /*
   2  * Copyright (C) 2011 Red Hat, Inc. All rights reserved.
   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  * Low level disk format
  15  *
  16  * Bitmap btree
  17  * ------------
  18  *
  19  * Each value stored in the btree is an index_entry.  This points to a
  20  * block that is used as a bitmap.  Within the bitmap hold 2 bits per
  21  * entry, which represent UNUSED = 0, REF_COUNT = 1, REF_COUNT = 2 and
  22  * REF_COUNT = many.
  23  *
  24  * Refcount btree
  25  * --------------
  26  *
  27  * Any entry that has a ref count higher than 2 gets entered in the ref
  28  * count tree.  The leaf values for this tree is the 32-bit ref count.
  29  *---------------------------------------------------------------------
  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         struct dm_transaction_manager *tm;
  50         struct dm_btree_info bitmap_info;
  51         struct dm_btree_info ref_count_info;
  52
  53         uint32_t block_size;
  54         uint32_t entries_per_block;
  55         dm_block_t nr_blocks;
  56         dm_block_t nr_allocated;
  57
  58         /*
  59          * bitmap_root may be a btree root or a simple index.
  60          */
  61         dm_block_t bitmap_root;
  62
  63         dm_block_t ref_count_root;
  64
  65         struct disk_metadata_index mi_le;
  66 };
  67
  68 struct disk_sm_root {
  69         __le64 nr_blocks;
  70         __le64 nr_allocated;
  71         __le64 bitmap_root;
  72         __le64 ref_count_root;
  73 } __packed;
  74
  75 #define ENTRIES_PER_BYTE 4
  76
  77 struct disk_bitmap_header {
  78         __le32 csum;
  79         __le32 not_used;
  80         __le64 blocknr;
  81 } __packed;
  82
  83 /*
  84  * These bitops work on a block's worth of bits.
  85  */
  86 unsigned sm_lookup_bitmap(void *addr, unsigned b);
  87 void sm_set_bitmap(void *addr, unsigned b, unsigned val);
  88 int sm_find_free(void *addr, unsigned begin, unsigned end, unsigned *result);
  89
  90 void *dm_bitmap_data(struct dm_block *b);
  91
  92 extern struct dm_block_validator dm_sm_bitmap_validator;
  93
  94 #endif  /* DM_SPACE_MAP_COMMON_H */