fs/btrfs/extent_map.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2
   3 #ifndef BTRFS_EXTENT_MAP_H
   4 #define BTRFS_EXTENT_MAP_H
   5
   6 #include <linux/rbtree.h>
   7 #include <linux/refcount.h>
   8 #include "misc.h"
   9 #include "compression.h"
  10
  11 #define EXTENT_MAP_LAST_BYTE ((u64)-4)
  12 #define EXTENT_MAP_HOLE ((u64)-3)
  13 #define EXTENT_MAP_INLINE ((u64)-2)
  14
  15 /* bits for the extent_map::flags field */
  16 enum {
  17         /* this entry not yet on disk, don't free it */
  18         ENUM_BIT(EXTENT_FLAG_PINNED),
  19         ENUM_BIT(EXTENT_FLAG_COMPRESS_ZLIB),
  20         ENUM_BIT(EXTENT_FLAG_COMPRESS_LZO),
  21         ENUM_BIT(EXTENT_FLAG_COMPRESS_ZSTD),
  22         /* pre-allocated extent */
  23         ENUM_BIT(EXTENT_FLAG_PREALLOC),
  24         /* Logging this extent */
  25         ENUM_BIT(EXTENT_FLAG_LOGGING),
  26         /* Filling in a preallocated extent */
  27         ENUM_BIT(EXTENT_FLAG_FILLING),
  28         /* This em is merged from two or more physically adjacent ems */
  29         ENUM_BIT(EXTENT_FLAG_MERGED),
  30 };
  31
  32 /*
  33  * Keep this structure as compact as possible, as we can have really large
  34  * amounts of allocated extent maps at any time.
  35  */
  36 struct extent_map {
  37         struct rb_node rb_node;
  38
  39         /* all of these are in bytes */
  40         u64 start;
  41         u64 len;
  42         u64 mod_start;
  43         u64 mod_len;
  44         u64 orig_start;
  45         u64 orig_block_len;
  46         u64 ram_bytes;
  47         u64 block_start;
  48         u64 block_len;
  49
  50         /*
  51          * Generation of the extent map, for merged em it's the highest
  52          * generation of all merged ems.
  53          * For non-merged extents, it's from btrfs_file_extent_item::generation.
  54          */
  55         u64 generation;
  56         u32 flags;
  57         refcount_t refs;
  58         struct list_head list;
  59 };
  60
  61 struct extent_map_tree {
  62         struct rb_root_cached map;
  63         struct list_head modified_extents;
  64         rwlock_t lock;
  65 };
  66
  67 struct btrfs_inode;
  68
  69 static inline void extent_map_set_compression(struct extent_map *em,
  70                                               enum btrfs_compression_type type)
  71 {
  72         if (type == BTRFS_COMPRESS_ZLIB)
  73                 em->flags |= EXTENT_FLAG_COMPRESS_ZLIB;
  74         else if (type == BTRFS_COMPRESS_LZO)
  75                 em->flags |= EXTENT_FLAG_COMPRESS_LZO;
  76         else if (type == BTRFS_COMPRESS_ZSTD)
  77                 em->flags |= EXTENT_FLAG_COMPRESS_ZSTD;
  78 }
  79
  80 static inline enum btrfs_compression_type extent_map_compression(const struct extent_map *em)
  81 {
  82         if (em->flags & EXTENT_FLAG_COMPRESS_ZLIB)
  83                 return BTRFS_COMPRESS_ZLIB;
  84
  85         if (em->flags & EXTENT_FLAG_COMPRESS_LZO)
  86                 return BTRFS_COMPRESS_LZO;
  87
  88         if (em->flags & EXTENT_FLAG_COMPRESS_ZSTD)
  89                 return BTRFS_COMPRESS_ZSTD;
  90
  91         return BTRFS_COMPRESS_NONE;
  92 }
  93
  94 /*
  95  * More efficient way to determine if extent is compressed, instead of using
  96  * 'extent_map_compression() != BTRFS_COMPRESS_NONE'.
  97  */
  98 static inline bool extent_map_is_compressed(const struct extent_map *em)
  99 {
 100         return (em->flags & (EXTENT_FLAG_COMPRESS_ZLIB |
 101                              EXTENT_FLAG_COMPRESS_LZO |
 102                              EXTENT_FLAG_COMPRESS_ZSTD)) != 0;
 103 }
 104
 105 static inline int extent_map_in_tree(const struct extent_map *em)
 106 {
 107         return !RB_EMPTY_NODE(&em->rb_node);
 108 }
 109
 110 static inline u64 extent_map_end(const struct extent_map *em)
 111 {
 112         if (em->start + em->len < em->start)
 113                 return (u64)-1;
 114         return em->start + em->len;
 115 }
 116
 117 void extent_map_tree_init(struct extent_map_tree *tree);
 118 struct extent_map *lookup_extent_mapping(struct extent_map_tree *tree,
 119                                          u64 start, u64 len);
 120 void remove_extent_mapping(struct extent_map_tree *tree, struct extent_map *em);
 121 int split_extent_map(struct btrfs_inode *inode, u64 start, u64 len, u64 pre,
 122                      u64 new_logical);
 123
 124 struct extent_map *alloc_extent_map(void);
 125 void free_extent_map(struct extent_map *em);
 126 int __init extent_map_init(void);
 127 void __cold extent_map_exit(void);
 128 int unpin_extent_cache(struct btrfs_inode *inode, u64 start, u64 len, u64 gen);
 129 void clear_em_logging(struct extent_map_tree *tree, struct extent_map *em);
 130 struct extent_map *search_extent_mapping(struct extent_map_tree *tree,
 131                                          u64 start, u64 len);
 132 int btrfs_add_extent_mapping(struct btrfs_fs_info *fs_info,
 133                              struct extent_map_tree *em_tree,
 134                              struct extent_map **em_in, u64 start, u64 len);
 135 void btrfs_drop_extent_map_range(struct btrfs_inode *inode,
 136                                  u64 start, u64 end,
 137                                  bool skip_pinned);
 138 int btrfs_replace_extent_map_range(struct btrfs_inode *inode,
 139                                    struct extent_map *new_em,
 140                                    bool modified);
 141
 142 #endif