1 /* SPDX-License-Identifier: GPL-2.0 */ 2 3 #ifndef BTRFS_EXTENT_MAP_H 4 #define BTRFS_EXTENT_MAP_H 5 6 #include <linux/compiler_types.h> 7 #include <linux/spinlock_types.h> 8 #include <linux/rbtree.h> 9 #include <linux/list.h> 10 #include <linux/refcount.h> 11 #include "fs.h" 12 13 struct btrfs_inode; 14 struct btrfs_fs_info; 15 16 #define EXTENT_MAP_LAST_BYTE ((u64)-4) 17 #define EXTENT_MAP_HOLE ((u64)-3) 18 #define EXTENT_MAP_INLINE ((u64)-2) 19 20 /* bits for the extent_map::flags field */ 21 enum { 22 /* this entry not yet on disk, don't free it */ 23 ENUM_BIT(EXTENT_FLAG_PINNED), 24 ENUM_BIT(EXTENT_FLAG_COMPRESS_ZLIB), 25 ENUM_BIT(EXTENT_FLAG_COMPRESS_LZO), 26 ENUM_BIT(EXTENT_FLAG_COMPRESS_ZSTD), 27 /* pre-allocated extent */ 28 ENUM_BIT(EXTENT_FLAG_PREALLOC), 29 /* Logging this extent */ 30 ENUM_BIT(EXTENT_FLAG_LOGGING), 31 /* This em is merged from two or more physically adjacent ems */ 32 ENUM_BIT(EXTENT_FLAG_MERGED), 33 }; 34 35 /* 36 * This structure represents file extents and holes. 37 * 38 * Unlike on-disk file extent items, extent maps can be merged to save memory. 39 * This means members only match file extent items before any merging. 40 * 41 * Keep this structure as compact as possible, as we can have really large 42 * amounts of allocated extent maps at any time. 43 */ 44 struct extent_map { 45 struct rb_node rb_node; 46 47 /* All of these are in bytes. */ 48 49 /* File offset matching the offset of a BTRFS_EXTENT_ITEM_KEY key. */ 50 u64 start; 51 52 /* 53 * Length of the file extent. 54 * 55 * For non-inlined file extents it's btrfs_file_extent_item::num_bytes. 56 * For inline extents it's sectorsize, since inline data starts at 57 * offsetof(struct btrfs_file_extent_item, disk_bytenr) thus 58 * btrfs_file_extent_item::num_bytes is not valid. 59 */ 60 u64 len; 61 62 /* 63 * The bytenr of the full on-disk extent. 64 * 65 * For regular extents it's btrfs_file_extent_item::disk_bytenr. 66 * For holes it's EXTENT_MAP_HOLE and for inline extents it's 67 * EXTENT_MAP_INLINE. 68 */ 69 u64 disk_bytenr; 70 71 /* 72 * The full on-disk extent length, matching 73 * btrfs_file_extent_item::disk_num_bytes. 74 */ 75 u64 disk_num_bytes; 76 77 /* 78 * Offset inside the decompressed extent. 79 * 80 * For regular extents it's btrfs_file_extent_item::offset. 81 * For holes and inline extents it's 0. 82 */ 83 u64 offset; 84 85 /* 86 * The decompressed size of the whole on-disk extent, matching 87 * btrfs_file_extent_item::ram_bytes. 88 */ 89 u64 ram_bytes; 90 91 /* 92 * Generation of the extent map, for merged em it's the highest 93 * generation of all merged ems. 94 * For non-merged extents, it's from btrfs_file_extent_item::generation. 95 */ 96 u64 generation; 97 u32 flags; 98 refcount_t refs; 99 struct list_head list; 100 }; 101 102 struct extent_map_tree { 103 struct rb_root root; 104 struct list_head modified_extents; 105 rwlock_t lock; 106 }; 107 108 struct btrfs_inode; 109 110 static inline void btrfs_extent_map_set_compression(struct extent_map *em, 111 enum btrfs_compression_type type) 112 { 113 if (type == BTRFS_COMPRESS_ZLIB) 114 em->flags |= EXTENT_FLAG_COMPRESS_ZLIB; 115 else if (type == BTRFS_COMPRESS_LZO) 116 em->flags |= EXTENT_FLAG_COMPRESS_LZO; 117 else if (type == BTRFS_COMPRESS_ZSTD) 118 em->flags |= EXTENT_FLAG_COMPRESS_ZSTD; 119 } 120 121 static inline enum btrfs_compression_type btrfs_extent_map_compression( 122 const struct extent_map *em) 123 { 124 if (em->flags & EXTENT_FLAG_COMPRESS_ZLIB) 125 return BTRFS_COMPRESS_ZLIB; 126 127 if (em->flags & EXTENT_FLAG_COMPRESS_LZO) 128 return BTRFS_COMPRESS_LZO; 129 130 if (em->flags & EXTENT_FLAG_COMPRESS_ZSTD) 131 return BTRFS_COMPRESS_ZSTD; 132 133 return BTRFS_COMPRESS_NONE; 134 } 135 136 /* 137 * More efficient way to determine if extent is compressed, instead of using 138 * 'extent_map_compression() != BTRFS_COMPRESS_NONE'. 139 */ 140 static inline bool btrfs_extent_map_is_compressed(const struct extent_map *em) 141 { 142 return (em->flags & (EXTENT_FLAG_COMPRESS_ZLIB | 143 EXTENT_FLAG_COMPRESS_LZO | 144 EXTENT_FLAG_COMPRESS_ZSTD)) != 0; 145 } 146 147 static inline int btrfs_extent_map_in_tree(const struct extent_map *em) 148 { 149 return !RB_EMPTY_NODE(&em->rb_node); 150 } 151 152 static inline u64 btrfs_extent_map_block_start(const struct extent_map *em) 153 { 154 if (em->disk_bytenr < EXTENT_MAP_LAST_BYTE) { 155 if (btrfs_extent_map_is_compressed(em)) 156 return em->disk_bytenr; 157 return em->disk_bytenr + em->offset; 158 } 159 return em->disk_bytenr; 160 } 161 162 static inline u64 btrfs_extent_map_end(const struct extent_map *em) 163 { 164 if (em->start + em->len < em->start) 165 return (u64)-1; 166 return em->start + em->len; 167 } 168 169 void btrfs_extent_map_tree_init(struct extent_map_tree *tree); 170 struct extent_map *btrfs_lookup_extent_mapping(struct extent_map_tree *tree, 171 u64 start, u64 len); 172 void btrfs_remove_extent_mapping(struct btrfs_inode *inode, struct extent_map *em); 173 int btrfs_split_extent_map(struct btrfs_inode *inode, u64 start, u64 len, u64 pre, 174 u64 new_logical); 175 176 struct extent_map *btrfs_alloc_extent_map(void); 177 void btrfs_free_extent_map(struct extent_map *em); 178 int __init btrfs_extent_map_init(void); 179 void __cold btrfs_extent_map_exit(void); 180 int btrfs_unpin_extent_cache(struct btrfs_inode *inode, u64 start, u64 len, u64 gen); 181 void btrfs_clear_em_logging(struct btrfs_inode *inode, struct extent_map *em); 182 struct extent_map *btrfs_search_extent_mapping(struct extent_map_tree *tree, 183 u64 start, u64 len); 184 int btrfs_add_extent_mapping(struct btrfs_inode *inode, 185 struct extent_map **em_in, u64 start, u64 len); 186 void btrfs_drop_extent_map_range(struct btrfs_inode *inode, 187 u64 start, u64 end, 188 bool skip_pinned); 189 int btrfs_replace_extent_map_range(struct btrfs_inode *inode, 190 struct extent_map *new_em, 191 bool modified); 192 void btrfs_free_extent_maps(struct btrfs_fs_info *fs_info, long nr_to_scan); 193 void btrfs_init_extent_map_shrinker_work(struct btrfs_fs_info *fs_info); 194 195 #endif 196