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1/* SPDX-License-Identifier: GPL-2.0 */2 3#ifndef BTRFS_EXTENT_MAP_H4#define BTRFS_EXTENT_MAP_H5 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 14struct btrfs_inode;15struct 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 */22enum {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 large43 * amounts of allocated extent maps at any time.44 */45struct 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 at58 * offsetof(struct btrfs_file_extent_item, disk_bytenr) thus59 * 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's68 * EXTENT_MAP_INLINE.69 */70 u64 disk_bytenr;71 72 /*73 * The full on-disk extent length, matching74 * 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, matching88 * 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 highest94 * 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 103struct extent_map_tree {104 struct rb_root root;105 struct list_head modified_extents;106 rwlock_t lock;107};108 109struct btrfs_inode;110 111static inline void 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 122static inline enum btrfs_compression_type extent_map_compression(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 using138 * 'extent_map_compression() != BTRFS_COMPRESS_NONE'.139 */140static inline bool 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 147static inline int extent_map_in_tree(const struct extent_map *em)148{149 return !RB_EMPTY_NODE(&em->rb_node);150}151 152static inline u64 extent_map_block_start(const struct extent_map *em)153{154 if (em->disk_bytenr < EXTENT_MAP_LAST_BYTE) {155 if (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 162static inline u64 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 169void extent_map_tree_init(struct extent_map_tree *tree);170struct extent_map *lookup_extent_mapping(struct extent_map_tree *tree,171 u64 start, u64 len);172void remove_extent_mapping(struct btrfs_inode *inode, struct extent_map *em);173int split_extent_map(struct btrfs_inode *inode, u64 start, u64 len, u64 pre,174 u64 new_logical);175 176struct extent_map *alloc_extent_map(void);177void free_extent_map(struct extent_map *em);178int __init extent_map_init(void);179void __cold extent_map_exit(void);180int unpin_extent_cache(struct btrfs_inode *inode, u64 start, u64 len, u64 gen);181void clear_em_logging(struct btrfs_inode *inode, struct extent_map *em);182struct extent_map *search_extent_mapping(struct extent_map_tree *tree,183 u64 start, u64 len);184int btrfs_add_extent_mapping(struct btrfs_inode *inode,185 struct extent_map **em_in, u64 start, u64 len);186void btrfs_drop_extent_map_range(struct btrfs_inode *inode,187 u64 start, u64 end,188 bool skip_pinned);189int btrfs_replace_extent_map_range(struct btrfs_inode *inode,190 struct extent_map *new_em,191 bool modified);192long btrfs_free_extent_maps(struct btrfs_fs_info *fs_info, long nr_to_scan);193 194#endif195