fs/btrfs/extent_map.h

   1 #ifndef __EXTENTMAP__
   2 #define __EXTENTMAP__
   3
   4 #include <linux/rbtree.h>
   5 #include <linux/refcount.h>
   6
   7 #define EXTENT_MAP_LAST_BYTE ((u64)-4)
   8 #define EXTENT_MAP_HOLE ((u64)-3)
   9 #define EXTENT_MAP_INLINE ((u64)-2)
  10 #define EXTENT_MAP_DELALLOC ((u64)-1)
  11
  12 /* bits for the flags field */
  13 #define EXTENT_FLAG_PINNED 0 /* this entry not yet on disk, don't free it */
  14 #define EXTENT_FLAG_COMPRESSED 1
  15 #define EXTENT_FLAG_VACANCY 2 /* no file extent item found */
  16 #define EXTENT_FLAG_PREALLOC 3 /* pre-allocated extent */
  17 #define EXTENT_FLAG_LOGGING 4 /* Logging this extent */
  18 #define EXTENT_FLAG_FILLING 5 /* Filling in a preallocated extent */
  19 #define EXTENT_FLAG_FS_MAPPING 6 /* filesystem extent mapping type */
  20
  21 struct extent_map {
  22         struct rb_node rb_node;
  23
  24         /* all of these are in bytes */
  25         u64 start;
  26         u64 len;
  27         u64 mod_start;
  28         u64 mod_len;
  29         u64 orig_start;
  30         u64 orig_block_len;
  31         u64 ram_bytes;
  32         u64 block_start;
  33         u64 block_len;
  34         u64 generation;
  35         unsigned long flags;
  36         union {
  37                 struct block_device *bdev;
  38
  39                 /*
  40                  * used for chunk mappings
  41                  * flags & EXTENT_FLAG_FS_MAPPING must be set
  42                  */
  43                 struct map_lookup *map_lookup;
  44         };
  45         refcount_t refs;
  46         unsigned int compress_type;
  47         struct list_head list;
  48 };
  49
  50 struct extent_map_tree {
  51         struct rb_root map;
  52         struct list_head modified_extents;
  53         rwlock_t lock;
  54 };
  55
  56 static inline int extent_map_in_tree(const struct extent_map *em)
  57 {
  58         return !RB_EMPTY_NODE(&em->rb_node);
  59 }
  60
  61 static inline u64 extent_map_end(struct extent_map *em)
  62 {
  63         if (em->start + em->len < em->start)
  64                 return (u64)-1;
  65         return em->start + em->len;
  66 }
  67
  68 static inline u64 extent_map_block_end(struct extent_map *em)
  69 {
  70         if (em->block_start + em->block_len < em->block_start)
  71                 return (u64)-1;
  72         return em->block_start + em->block_len;
  73 }
  74
  75 void extent_map_tree_init(struct extent_map_tree *tree);
  76 struct extent_map *lookup_extent_mapping(struct extent_map_tree *tree,
  77                                          u64 start, u64 len);
  78 int add_extent_mapping(struct extent_map_tree *tree,
  79                        struct extent_map *em, int modified);
  80 int remove_extent_mapping(struct extent_map_tree *tree, struct extent_map *em);
  81 void replace_extent_mapping(struct extent_map_tree *tree,
  82                             struct extent_map *cur,
  83                             struct extent_map *new,
  84                             int modified);
  85
  86 struct extent_map *alloc_extent_map(void);
  87 void free_extent_map(struct extent_map *em);
  88 int __init extent_map_init(void);
  89 void extent_map_exit(void);
  90 int unpin_extent_cache(struct extent_map_tree *tree, u64 start, u64 len, u64 gen);
  91 void clear_em_logging(struct extent_map_tree *tree, struct extent_map *em);
  92 struct extent_map *search_extent_mapping(struct extent_map_tree *tree,
  93                                          u64 start, u64 len);
  94 #endif