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#define EXTENT_FLAG_LOGGING 4 /* Logging this extent */
  17
  18struct extent_map {
  19        struct rb_node rb_node;
  20
  21        /* all of these are in bytes */
  22        u64 start;
  23        u64 len;
  24        u64 mod_start;
  25        u64 mod_len;
  26        u64 orig_start;
  27        u64 block_start;
  28        u64 block_len;
  29        u64 generation;
  30        unsigned long flags;
  31        struct block_device *bdev;
  32        atomic_t refs;
  33        unsigned int in_tree;
  34        unsigned int compress_type;
  35        struct list_head list;
  36};
  37
  38struct extent_map_tree {
  39        struct rb_root map;
  40        struct list_head modified_extents;
  41        rwlock_t lock;
  42};
  43
  44static inline u64 extent_map_end(struct extent_map *em)
  45{
  46        if (em->start + em->len < em->start)
  47                return (u64)-1;
  48        return em->start + em->len;
  49}
  50
  51static inline u64 extent_map_block_end(struct extent_map *em)
  52{
  53        if (em->block_start + em->block_len < em->block_start)
  54                return (u64)-1;
  55        return em->block_start + em->block_len;
  56}
  57
  58void extent_map_tree_init(struct extent_map_tree *tree);
  59struct extent_map *lookup_extent_mapping(struct extent_map_tree *tree,
  60                                         u64 start, u64 len);
  61int add_extent_mapping(struct extent_map_tree *tree,
  62                       struct extent_map *em);
  63int remove_extent_mapping(struct extent_map_tree *tree, struct extent_map *em);
  64
  65struct extent_map *alloc_extent_map(void);
  66void free_extent_map(struct extent_map *em);
  67int __init extent_map_init(void);
  68void extent_map_exit(void);
  69int unpin_extent_cache(struct extent_map_tree *tree, u64 start, u64 len, u64 gen);
  70struct extent_map *search_extent_mapping(struct extent_map_tree *tree,
  71                                         u64 start, u64 len);
  72#endif
  73
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