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 };
82 
83 struct 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 
92 struct disk_bitmap_header {
93 	__le32 csum;
94 	__le32 not_used;
95 	__le64 blocknr;
96 } __packed;
97 
98 enum allocation_event {
99 	SM_NONE,
100 	SM_ALLOC,
101 	SM_FREE,
102 };
103 
104 /*----------------------------------------------------------------*/
105 
106 int sm_ll_extend(struct ll_disk *ll, dm_block_t extra_blocks);
107 int sm_ll_lookup_bitmap(struct ll_disk *ll, dm_block_t b, uint32_t *result);
108 int sm_ll_lookup(struct ll_disk *ll, dm_block_t b, uint32_t *result);
109 int sm_ll_find_free_block(struct ll_disk *ll, dm_block_t begin,
110 			  dm_block_t end, dm_block_t *result);
111 int sm_ll_insert(struct ll_disk *ll, dm_block_t b, uint32_t ref_count, enum allocation_event *ev);
112 int sm_ll_inc(struct ll_disk *ll, dm_block_t b, enum allocation_event *ev);
113 int sm_ll_dec(struct ll_disk *ll, dm_block_t b, enum allocation_event *ev);
114 int sm_ll_commit(struct ll_disk *ll);
115 
116 int sm_ll_new_metadata(struct ll_disk *ll, struct dm_transaction_manager *tm);
117 int sm_ll_open_metadata(struct ll_disk *ll, struct dm_transaction_manager *tm,
118 			void *root_le, size_t len);
119 
120 int sm_ll_new_disk(struct ll_disk *ll, struct dm_transaction_manager *tm);
121 int 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