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