Root/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

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