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 #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
  20 struct 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
  49 struct extent_map_tree {
  50         struct rb_root map;
  51         struct list_head modified_extents;
  52         rwlock_t lock;
  53 };
  54
  55 static inline int extent_map_in_tree(const struct extent_map *em)
  56 {
  57         return !RB_EMPTY_NODE(&em->rb_node);
  58 }
  59
  60 static 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
  67 static 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
  74 void extent_map_tree_init(struct extent_map_tree *tree);
  75 struct extent_map *lookup_extent_mapping(struct extent_map_tree *tree,
  76                                          u64 start, u64 len);
  77 int add_extent_mapping(struct extent_map_tree *tree,
  78                        struct extent_map *em, int modified);
  79 int remove_extent_mapping(struct extent_map_tree *tree, struct extent_map *em);
  80 void replace_extent_mapping(struct extent_map_tree *tree,
  81                             struct extent_map *cur,
  82                             struct extent_map *new,
  83                             int modified);
  84
  85 struct extent_map *alloc_extent_map(void);
  86 void free_extent_map(struct extent_map *em);
  87 int __init extent_map_init(void);
  88 void extent_map_exit(void);
  89 int unpin_extent_cache(struct extent_map_tree *tree, u64 start, u64 len, u64 gen);
  90 void clear_em_logging(struct extent_map_tree *tree, struct extent_map *em);
  91 struct extent_map *search_extent_mapping(struct extent_map_tree *tree,
  92                                          u64 start, u64 len);
  93 #endif