dm-space-map-common.h revision 3241b1d3e0aaafbfcd320f4d71ade629728cc4f4 
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};
82
83struct disk_sm_root {
84	__le64 nr_blocks;
85	__le64 nr_allocated;
86	__le64 bitmap_root;
87	__le64 ref_count_root;
88} __packed;
89
90#define ENTRIES_PER_BYTE 4
91
92struct disk_bitmap_header {
93	__le32 csum;
94	__le32 not_used;
95	__le64 blocknr;
96} __packed;
97
98enum allocation_event {
99	SM_NONE,
100	SM_ALLOC,
101	SM_FREE,
102};
103
104/*----------------------------------------------------------------*/
105
106int sm_ll_extend(struct ll_disk *ll, dm_block_t extra_blocks);
107int sm_ll_lookup_bitmap(struct ll_disk *ll, dm_block_t b, uint32_t *result);
108int sm_ll_lookup(struct ll_disk *ll, dm_block_t b, uint32_t *result);
109int sm_ll_find_free_block(struct ll_disk *ll, dm_block_t begin,
110			  dm_block_t end, dm_block_t *result);
111int sm_ll_insert(struct ll_disk *ll, dm_block_t b, uint32_t ref_count, enum allocation_event *ev);
112int sm_ll_inc(struct ll_disk *ll, dm_block_t b, enum allocation_event *ev);
113int sm_ll_dec(struct ll_disk *ll, dm_block_t b, enum allocation_event *ev);
114int sm_ll_commit(struct ll_disk *ll);
115
116int sm_ll_new_metadata(struct ll_disk *ll, struct dm_transaction_manager *tm);
117int sm_ll_open_metadata(struct ll_disk *ll, struct dm_transaction_manager *tm,
118			void *root_le, size_t len);
119
120int sm_ll_new_disk(struct ll_disk *ll, struct dm_transaction_manager *tm);
121int sm_ll_open_disk(struct ll_disk *ll, struct dm_transaction_manager *tm,
122		    void *root_le, size_t len);
123
124/*----------------------------------------------------------------*/
125
126#endif	/* DM_SPACE_MAP_COMMON_H */
127