Root/fs/btrfs/extent_map.h

1#ifndef __EXTENTMAP__
2#define __EXTENTMAP__
3
4#include <linux/rbtree.h>
5
6#define EXTENT_MAP_LAST_BYTE (u64)-4
7#define EXTENT_MAP_HOLE (u64)-3
8#define EXTENT_MAP_INLINE (u64)-2
9#define EXTENT_MAP_DELALLOC (u64)-1
10
11/* bits for the flags field */
12#define EXTENT_FLAG_PINNED 0 /* this entry not yet on disk, don't free it */
13#define EXTENT_FLAG_COMPRESSED 1
14#define EXTENT_FLAG_VACANCY 2 /* no file extent item found */
15#define EXTENT_FLAG_PREALLOC 3 /* pre-allocated extent */
16
17struct extent_map {
18    struct rb_node rb_node;
19
20    /* all of these are in bytes */
21    u64 start;
22    u64 len;
23    u64 orig_start;
24    u64 block_start;
25    u64 block_len;
26    unsigned long flags;
27    struct block_device *bdev;
28    atomic_t refs;
29    int in_tree;
30};
31
32struct extent_map_tree {
33    struct rb_root map;
34    rwlock_t lock;
35};
36
37static inline u64 extent_map_end(struct extent_map *em)
38{
39    if (em->start + em->len < em->start)
40        return (u64)-1;
41    return em->start + em->len;
42}
43
44static inline u64 extent_map_block_end(struct extent_map *em)
45{
46    if (em->block_start + em->block_len < em->block_start)
47        return (u64)-1;
48    return em->block_start + em->block_len;
49}
50
51void extent_map_tree_init(struct extent_map_tree *tree, gfp_t mask);
52struct extent_map *lookup_extent_mapping(struct extent_map_tree *tree,
53                     u64 start, u64 len);
54int add_extent_mapping(struct extent_map_tree *tree,
55               struct extent_map *em);
56int remove_extent_mapping(struct extent_map_tree *tree, struct extent_map *em);
57
58struct extent_map *alloc_extent_map(gfp_t mask);
59void free_extent_map(struct extent_map *em);
60int __init extent_map_init(void);
61void extent_map_exit(void);
62int unpin_extent_cache(struct extent_map_tree *tree, u64 start, u64 len);
63struct extent_map *search_extent_mapping(struct extent_map_tree *tree,
64                     u64 start, u64 len);
65#endif
66

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