linux/fs/btrfs/extent_map.h
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   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        unsigned int in_tree;
  30        unsigned int compress_type;
  31};
  32
  33struct extent_map_tree {
  34        struct rb_root map;
  35        rwlock_t lock;
  36};
  37
  38static inline u64 extent_map_end(struct extent_map *em)
  39{
  40        if (em->start + em->len < em->start)
  41                return (u64)-1;
  42        return em->start + em->len;
  43}
  44
  45static inline u64 extent_map_block_end(struct extent_map *em)
  46{
  47        if (em->block_start + em->block_len < em->block_start)
  48                return (u64)-1;
  49        return em->block_start + em->block_len;
  50}
  51
  52void extent_map_tree_init(struct extent_map_tree *tree);
  53struct extent_map *lookup_extent_mapping(struct extent_map_tree *tree,
  54                                         u64 start, u64 len);
  55int add_extent_mapping(struct extent_map_tree *tree,
  56                       struct extent_map *em);
  57int remove_extent_mapping(struct extent_map_tree *tree, struct extent_map *em);
  58
  59struct extent_map *alloc_extent_map(void);
  60void free_extent_map(struct extent_map *em);
  61int __init extent_map_init(void);
  62void extent_map_exit(void);
  63int unpin_extent_cache(struct extent_map_tree *tree, u64 start, u64 len);
  64struct extent_map *search_extent_mapping(struct extent_map_tree *tree,
  65                                         u64 start, u64 len);
  66#endif
  67
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