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 "misc.h" 12 #include "compression.h" 13 14 struct btrfs_inode; 15 struct btrfs_fs_info; 16 17 #define EXTENT_MAP_LAST_BYTE ((u64)-4) 18 #define EXTENT_MAP_HOLE ((u64)-3) 19 #define EXTENT_MAP_INLINE ((u64)-2) 20 21 /* bits for the extent_map::flags field */ 22 enum { 23 /* this entry not yet on disk, don't free it */ 24 ENUM_BIT(EXTENT_FLAG_PINNED), 25 ENUM_BIT(EXTENT_FLAG_COMPRESS_ZLIB), 26 ENUM_BIT(EXTENT_FLAG_COMPRESS_LZO), 27 ENUM_BIT(EXTENT_FLAG_COMPRESS_ZSTD), 28 /* pre-allocated extent */ 29 ENUM_BIT(EXTENT_FLAG_PREALLOC), 30 /* Logging this extent */ 31 ENUM_BIT(EXTENT_FLAG_LOGGING), 32 /* This em is merged from two or more physically adjacent ems */ 33 ENUM_BIT(EXTENT_FLAG_MERGED), 34 }; 35 36 /* 37 * This structure represents file extents and holes. 38 * 39 * Unlike on-disk file extent items, extent maps can be merged to save memory. 40 * This means members only match file extent items before any merging. 41 * 42 * Keep this structure as compact as possible, as we can have really large 43 * amounts of allocated extent maps at any time. 44 */ 45 struct extent_map { 46 struct rb_node rb_node; 47 48 /* All of these are in bytes. */ 49 50 /* File offset matching the offset of a BTRFS_EXTENT_ITEM_KEY key. */ 51 u64 start; 52 53 /* 54 * Length of the file extent. 55 * 56 * For non-inlined file extents it's btrfs_file_extent_item::num_bytes. 57 * For inline extents it's sectorsize, since inline data starts at 58 * offsetof(struct btrfs_file_extent_item, disk_bytenr) thus 59 * btrfs_file_extent_item::num_bytes is not valid. 60 */ 61 u64 len; 62 63 /* 64 * The bytenr of the full on-disk extent. 65 * 66 * For regular extents it's btrfs_file_extent_item::disk_bytenr. 67 * For holes it's EXTENT_MAP_HOLE and for inline extents it's 68 * EXTENT_MAP_INLINE. 69 */ 70 u64 disk_bytenr; 71 72 /* 73 * The full on-disk extent length, matching 74 * btrfs_file_extent_item::disk_num_bytes. 75 */ 76 u64 disk_num_bytes; 77 78 /* 79 * Offset inside the decompressed extent. 80 * 81 * For regular extents it's btrfs_file_extent_item::offset. 82 * For holes and inline extents it's 0. 83 */ 84 u64 offset; 85 86 /* 87 * The decompressed size of the whole on-disk extent, matching 88 * btrfs_file_extent_item::ram_bytes. 89 */ 90 u64 ram_bytes; 91 92 /* 93 * Generation of the extent map, for merged em it's the highest 94 * generation of all merged ems. 95 * For non-merged extents, it's from btrfs_file_extent_item::generation. 96 */ 97 u64 generation; 98 u32 flags; 99 refcount_t refs; 100 struct list_head list; 101 }; 102 103 struct extent_map_tree { 104 struct rb_root root; 105 struct list_head modified_extents; 106 rwlock_t lock; 107 }; 108 109 struct btrfs_inode; 110 111 static inline void btrfs_extent_map_set_compression(struct extent_map *em, 112 enum btrfs_compression_type type) 113 { 114 if (type == BTRFS_COMPRESS_ZLIB) 115 em->flags |= EXTENT_FLAG_COMPRESS_ZLIB; 116 else if (type == BTRFS_COMPRESS_LZO) 117 em->flags |= EXTENT_FLAG_COMPRESS_LZO; 118 else if (type == BTRFS_COMPRESS_ZSTD) 119 em->flags |= EXTENT_FLAG_COMPRESS_ZSTD; 120 } 121 122 static inline enum btrfs_compression_type btrfs_extent_map_compression( 123 const struct extent_map *em) 124 { 125 if (em->flags & EXTENT_FLAG_COMPRESS_ZLIB) 126 return BTRFS_COMPRESS_ZLIB; 127 128 if (em->flags & EXTENT_FLAG_COMPRESS_LZO) 129 return BTRFS_COMPRESS_LZO; 130 131 if (em->flags & EXTENT_FLAG_COMPRESS_ZSTD) 132 return BTRFS_COMPRESS_ZSTD; 133 134 return BTRFS_COMPRESS_NONE; 135 } 136 137 /* 138 * More efficient way to determine if extent is compressed, instead of using 139 * 'extent_map_compression() != BTRFS_COMPRESS_NONE'. 140 */ 141 static inline bool btrfs_extent_map_is_compressed(const struct extent_map *em) 142 { 143 return (em->flags & (EXTENT_FLAG_COMPRESS_ZLIB | 144 EXTENT_FLAG_COMPRESS_LZO | 145 EXTENT_FLAG_COMPRESS_ZSTD)) != 0; 146 } 147 148 static inline int btrfs_extent_map_in_tree(const struct extent_map *em) 149 { 150 return !RB_EMPTY_NODE(&em->rb_node); 151 } 152 153 static inline u64 btrfs_extent_map_block_start(const struct extent_map *em) 154 { 155 if (em->disk_bytenr < EXTENT_MAP_LAST_BYTE) { 156 if (btrfs_extent_map_is_compressed(em)) 157 return em->disk_bytenr; 158 return em->disk_bytenr + em->offset; 159 } 160 return em->disk_bytenr; 161 } 162 163 static inline u64 btrfs_extent_map_end(const struct extent_map *em) 164 { 165 if (em->start + em->len < em->start) 166 return (u64)-1; 167 return em->start + em->len; 168 } 169 170 void btrfs_extent_map_tree_init(struct extent_map_tree *tree); 171 struct extent_map *btrfs_lookup_extent_mapping(struct extent_map_tree *tree, 172 u64 start, u64 len); 173 void btrfs_remove_extent_mapping(struct btrfs_inode *inode, struct extent_map *em); 174 int btrfs_split_extent_map(struct btrfs_inode *inode, u64 start, u64 len, u64 pre, 175 u64 new_logical); 176 177 struct extent_map *btrfs_alloc_extent_map(void); 178 void btrfs_free_extent_map(struct extent_map *em); 179 int __init btrfs_extent_map_init(void); 180 void __cold btrfs_extent_map_exit(void); 181 int btrfs_unpin_extent_cache(struct btrfs_inode *inode, u64 start, u64 len, u64 gen); 182 void btrfs_clear_em_logging(struct btrfs_inode *inode, struct extent_map *em); 183 struct extent_map *btrfs_search_extent_mapping(struct extent_map_tree *tree, 184 u64 start, u64 len); 185 int btrfs_add_extent_mapping(struct btrfs_inode *inode, 186 struct extent_map **em_in, u64 start, u64 len); 187 void btrfs_drop_extent_map_range(struct btrfs_inode *inode, 188 u64 start, u64 end, 189 bool skip_pinned); 190 int btrfs_replace_extent_map_range(struct btrfs_inode *inode, 191 struct extent_map *new_em, 192 bool modified); 193 void btrfs_free_extent_maps(struct btrfs_fs_info *fs_info, long nr_to_scan); 194 void btrfs_init_extent_map_shrinker_work(struct btrfs_fs_info *fs_info); 195 196 #endif 197