2 * Copyright (C) 2011 Red Hat, Inc.
4 * This file is released under the GPL.
7 #ifndef DM_SPACE_MAP_COMMON_H
8 #define DM_SPACE_MAP_COMMON_H
12 /*----------------------------------------------------------------*/
15 * Low level disk format
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
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.
32 struct disk_index_entry {
35 __le32 none_free_before;
36 } __attribute__ ((packed, aligned(8)));
39 #define MAX_METADATA_BITMAPS 255
40 struct disk_metadata_index {
45 struct disk_index_entry index[MAX_METADATA_BITMAPS];
46 } __attribute__ ((packed, aligned(8)));
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);
58 * A lot of time can be wasted reading and writing the same
59 * index entry. So we cache a few entries.
61 #define IE_CACHE_SIZE 64
62 #define IE_CACHE_MASK (IE_CACHE_SIZE - 1)
68 struct disk_index_entry ie;
72 struct dm_transaction_manager *tm;
73 struct dm_btree_info bitmap_info;
74 struct dm_btree_info ref_count_info;
77 uint32_t entries_per_block;
79 dm_block_t nr_allocated;
82 * bitmap_root may be a btree root or a simple index.
84 dm_block_t bitmap_root;
86 dm_block_t ref_count_root;
88 struct disk_metadata_index mi_le;
91 init_index_fn init_index;
92 open_index_fn open_index;
93 max_index_entries_fn max_entries;
95 bool bitmap_index_changed:1;
97 struct ie_cache ie_cache[IE_CACHE_SIZE];
100 struct disk_sm_root {
104 __le64 ref_count_root;
105 } __attribute__ ((packed, aligned(8)));
107 #define ENTRIES_PER_BYTE 4
109 struct disk_bitmap_header {
113 } __attribute__ ((packed, aligned(8)));
115 /*----------------------------------------------------------------*/
117 int sm_ll_extend(struct ll_disk *ll, dm_block_t extra_blocks);
118 int sm_ll_lookup_bitmap(struct ll_disk *ll, dm_block_t b, uint32_t *result);
119 int sm_ll_lookup(struct ll_disk *ll, dm_block_t b, uint32_t *result);
120 int sm_ll_find_free_block(struct ll_disk *ll, dm_block_t begin,
121 dm_block_t end, dm_block_t *result);
122 int sm_ll_find_common_free_block(struct ll_disk *old_ll, struct ll_disk *new_ll,
123 dm_block_t begin, dm_block_t end, dm_block_t *result);
126 * The next three functions return (via nr_allocations) the net number of
127 * allocations that were made. This number may be negative if there were
128 * more frees than allocs.
130 int sm_ll_insert(struct ll_disk *ll, dm_block_t b, uint32_t ref_count, int32_t *nr_allocations);
131 int sm_ll_inc(struct ll_disk *ll, dm_block_t b, dm_block_t e, int32_t *nr_allocations);
132 int sm_ll_dec(struct ll_disk *ll, dm_block_t b, dm_block_t e, int32_t *nr_allocations);
133 int sm_ll_commit(struct ll_disk *ll);
135 int sm_ll_new_metadata(struct ll_disk *ll, struct dm_transaction_manager *tm);
136 int sm_ll_open_metadata(struct ll_disk *ll, struct dm_transaction_manager *tm,
137 void *root_le, size_t len);
139 int sm_ll_new_disk(struct ll_disk *ll, struct dm_transaction_manager *tm);
140 int sm_ll_open_disk(struct ll_disk *ll, struct dm_transaction_manager *tm,
141 void *root_le, size_t len);
143 /*----------------------------------------------------------------*/
145 #endif /* DM_SPACE_MAP_COMMON_H */