/* SPDX-License-Identifier: GPL-2.0-only */
/*
* Copyright (C) 2011 Red Hat, Inc.
*
* This file is released under the GPL.
*/
#ifndef DM_SPACE_MAP_COMMON_H
#define DM_SPACE_MAP_COMMON_H
#include "dm-btree.h"
/*----------------------------------------------------------------*/
/*
* Low level disk format
*
* Bitmap btree
* ------------
*
* Each value stored in the btree is an index_entry. This points to a
* block that is used as a bitmap. Within the bitmap hold 2 bits per
* entry, which represent UNUSED = 0, REF_COUNT = 1, REF_COUNT = 2 and
* REF_COUNT = many.
*
* Refcount btree
* --------------
*
* Any entry that has a ref count higher than 2 gets entered in the ref
* count tree. The leaf values for this tree is the 32-bit ref count.
*/
struct disk_index_entry {
__le64 blocknr;
__le32 nr_free;
__le32 none_free_before;
} __packed __aligned(8);
#define MAX_METADATA_BITMAPS 255
struct disk_metadata_index {
__le32 csum;
__le32 padding;
__le64 blocknr;
struct disk_index_entry index[MAX_METADATA_BITMAPS];
} __packed __aligned(8);
struct ll_disk;
typedef int (*load_ie_fn)(struct ll_disk *ll, dm_block_t index, struct disk_index_entry *result);
typedef int (*save_ie_fn)(struct ll_disk *ll, dm_block_t index, struct disk_index_entry *ie);
typedef int (*init_index_fn)(struct ll_disk *ll);
typedef int (*open_index_fn)(struct ll_disk *ll);
typedef dm_block_t (*max_index_entries_fn)(struct ll_disk *ll);
typedef int (*commit_fn)(struct ll_disk *ll);
/*
* A lot of time can be wasted reading and writing the same
* index entry. So we cache a few entries.
*/
#define IE_CACHE_SIZE 64
#define IE_CACHE_MASK (IE_CACHE_SIZE - 1)
struct ie_cache {
bool valid;
bool dirty;
dm_block_t index;
struct disk_index_entry ie;
};
struct ll_disk {
struct dm_transaction_manager *tm;
struct dm_btree_info bitmap_info;
struct dm_btree_info ref_count_info;
uint32_t block_size;
uint32_t entries_per_block;
dm_block_t nr_blocks;
dm_block_t nr_allocated;
/*
* bitmap_root may be a btree root or a simple index.
*/
dm_block_t bitmap_root;
dm_block_t ref_count_root;
struct disk_metadata_index mi_le;
load_ie_fn load_ie;
save_ie_fn save_ie;
init_index_fn init_index;
open_index_fn open_index;
max_index_entries_fn max_entries;
commit_fn commit;
bool bitmap_index_changed:1;
struct ie_cache ie_cache[IE_CACHE_SIZE];
};
struct disk_sm_root {
__le64 nr_blocks;
__le64 nr_allocated;
__le64 bitmap_root;
__le64 ref_count_root;
} __packed __aligned(8);
#define ENTRIES_PER_BYTE 4
struct disk_bitmap_header {
__le32 csum;
__le32 not_used;
__le64 blocknr;
} __packed __aligned(8);
/*----------------------------------------------------------------*/
int sm_ll_extend(struct ll_disk *ll, dm_block_t extra_blocks);
int sm_ll_lookup_bitmap(struct ll_disk *ll, dm_block_t b, uint32_t *result);
int sm_ll_lookup(struct ll_disk *ll, dm_block_t b, uint32_t *result);
int sm_ll_find_free_block(struct ll_disk *ll, dm_block_t begin,
dm_block_t end, dm_block_t *result);
int sm_ll_find_common_free_block(struct ll_disk *old_ll, struct ll_disk *new_ll,
dm_block_t begin, dm_block_t end, dm_block_t *result);
/*
* The next three functions return (via nr_allocations) the net number of
* allocations that were made. This number may be negative if there were
* more frees than allocs.
*/
int sm_ll_insert(struct ll_disk *ll, dm_block_t b, uint32_t ref_count, int32_t *nr_allocations);
int sm_ll_inc(struct ll_disk *ll, dm_block_t b, dm_block_t e, int32_t *nr_allocations);
int sm_ll_dec(struct ll_disk *ll, dm_block_t b, dm_block_t e, int32_t *nr_allocations);
int sm_ll_commit(struct ll_disk *ll);
int sm_ll_new_metadata(struct ll_disk *ll, struct dm_transaction_manager *tm);
int sm_ll_open_metadata(struct ll_disk *ll, struct dm_transaction_manager *tm,
void *root_le, size_t len);
int sm_ll_new_disk(struct ll_disk *ll, struct dm_transaction_manager *tm);
int sm_ll_open_disk(struct ll_disk *ll, struct dm_transaction_manager *tm,
void *root_le, size_t len);
/*----------------------------------------------------------------*/
#endif /* DM_SPACE_MAP_COMMON_H */
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