LXR linux/fs/btrfs/extent

   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#define EXTENT_FLAG_FILLING 5 /* Filling in a preallocated extent */
  18#define EXTENT_FLAG_FS_MAPPING 6 /* filesystem extent mapping type */
  19
  20struct extent_map {
  21        struct rb_node rb_node;
  22
  23        /* all of these are in bytes */
  24        u64 start;
  25        u64 len;
  26        u64 mod_start;
  27        u64 mod_len;
  28        u64 orig_start;
  29        u64 orig_block_len;
  30        u64 ram_bytes;
  31        u64 block_start;
  32        u64 block_len;
  33        u64 generation;
  34        unsigned long flags;
  35        union {
  36                struct block_device *bdev;
  37
  38                /*
  39                 * used for chunk mappings
  40                 * flags & EXTENT_FLAG_FS_MAPPING must be set
  41                 */
  42                struct map_lookup *map_lookup;
  43        };
  44        atomic_t refs;
  45        unsigned int compress_type;
  46        struct list_head list;
  47};
  48
  49struct extent_map_tree {
  50        struct rb_root map;
  51        struct list_head modified_extents;
  52        rwlock_t lock;
  53};
  54
  55static inline int extent_map_in_tree(const struct extent_map *em)
  56{
  57        return !RB_EMPTY_NODE(&em->rb_node);
  58}
  59
  60static inline u64 extent_map_end(struct extent_map *em)
  61{
  62        if (em->start + em->len < em->start)
  63                return (u64)-1;
  64        return em->start + em->len;
  65}
  66
  67static inline u64 extent_map_block_end(struct extent_map *em)
  68{
  69        if (em->block_start + em->block_len < em->block_start)
  70                return (u64)-1;
  71        return em->block_start + em->block_len;
  72}
  73
  74void extent_map_tree_init(struct extent_map_tree *tree);
  75struct extent_map *lookup_extent_mapping(struct extent_map_tree *tree,
  76                                         u64 start, u64 len);
  77int add_extent_mapping(struct extent_map_tree *tree,
  78                       struct extent_map *em, int modified);
  79int remove_extent_mapping(struct extent_map_tree *tree, struct extent_map *em);
  80void replace_extent_mapping(struct extent_map_tree *tree,
  81                            struct extent_map *cur,
  82                            struct extent_map *new,
  83                            int modified);
  84
  85struct extent_map *alloc_extent_map(void);
  86void free_extent_map(struct extent_map *em);
  87int __init extent_map_init(void);
  88void extent_map_exit(void);
  89int unpin_extent_cache(struct extent_map_tree *tree, u64 start, u64 len, u64 gen);
  90void clear_em_logging(struct extent_map_tree *tree, struct extent_map *em);
  91struct extent_map *search_extent_mapping(struct extent_map_tree *tree,
  92                                         u64 start, u64 len);
  93#endif
  94