diff options
Diffstat (limited to 'fs/btrfs/extent_map.h')
| -rw-r--r-- | fs/btrfs/extent_map.h | 195 |
1 files changed, 195 insertions, 0 deletions
diff --git a/fs/btrfs/extent_map.h b/fs/btrfs/extent_map.h new file mode 100644 index 000000000..6f685f3c9 --- /dev/null +++ b/fs/btrfs/extent_map.h @@ -0,0 +1,195 @@ +/* SPDX-License-Identifier: GPL-2.0 */ + +#ifndef BTRFS_EXTENT_MAP_H +#define BTRFS_EXTENT_MAP_H + +#include <linux/compiler_types.h> +#include <linux/spinlock_types.h> +#include <linux/rbtree.h> +#include <linux/list.h> +#include <linux/refcount.h> +#include "fs.h" + +struct btrfs_inode; +struct btrfs_fs_info; + +#define EXTENT_MAP_LAST_BYTE ((u64)-4) +#define EXTENT_MAP_HOLE ((u64)-3) +#define EXTENT_MAP_INLINE ((u64)-2) + +/* bits for the extent_map::flags field */ +enum { + /* this entry not yet on disk, don't free it */ + ENUM_BIT(EXTENT_FLAG_PINNED), + ENUM_BIT(EXTENT_FLAG_COMPRESS_ZLIB), + ENUM_BIT(EXTENT_FLAG_COMPRESS_LZO), + ENUM_BIT(EXTENT_FLAG_COMPRESS_ZSTD), + /* pre-allocated extent */ + ENUM_BIT(EXTENT_FLAG_PREALLOC), + /* Logging this extent */ + ENUM_BIT(EXTENT_FLAG_LOGGING), + /* This em is merged from two or more physically adjacent ems */ + ENUM_BIT(EXTENT_FLAG_MERGED), +}; + +/* + * This structure represents file extents and holes. + * + * Unlike on-disk file extent items, extent maps can be merged to save memory. + * This means members only match file extent items before any merging. + * + * Keep this structure as compact as possible, as we can have really large + * amounts of allocated extent maps at any time. + */ +struct extent_map { + struct rb_node rb_node; + + /* All of these are in bytes. */ + + /* File offset matching the offset of a BTRFS_EXTENT_ITEM_KEY key. */ + u64 start; + + /* + * Length of the file extent. + * + * For non-inlined file extents it's btrfs_file_extent_item::num_bytes. + * For inline extents it's sectorsize, since inline data starts at + * offsetof(struct btrfs_file_extent_item, disk_bytenr) thus + * btrfs_file_extent_item::num_bytes is not valid. + */ + u64 len; + + /* + * The bytenr of the full on-disk extent. + * + * For regular extents it's btrfs_file_extent_item::disk_bytenr. + * For holes it's EXTENT_MAP_HOLE and for inline extents it's + * EXTENT_MAP_INLINE. + */ + u64 disk_bytenr; + + /* + * The full on-disk extent length, matching + * btrfs_file_extent_item::disk_num_bytes. + */ + u64 disk_num_bytes; + + /* + * Offset inside the decompressed extent. + * + * For regular extents it's btrfs_file_extent_item::offset. + * For holes and inline extents it's 0. + */ + u64 offset; + + /* + * The decompressed size of the whole on-disk extent, matching + * btrfs_file_extent_item::ram_bytes. + */ + u64 ram_bytes; + + /* + * Generation of the extent map, for merged em it's the highest + * generation of all merged ems. + * For non-merged extents, it's from btrfs_file_extent_item::generation. + */ + u64 generation; + u32 flags; + refcount_t refs; + struct list_head list; +}; + +struct extent_map_tree { + struct rb_root root; + struct list_head modified_extents; + rwlock_t lock; +}; + +struct btrfs_inode; + +static inline void btrfs_extent_map_set_compression(struct extent_map *em, + enum btrfs_compression_type type) +{ + if (type == BTRFS_COMPRESS_ZLIB) + em->flags |= EXTENT_FLAG_COMPRESS_ZLIB; + else if (type == BTRFS_COMPRESS_LZO) + em->flags |= EXTENT_FLAG_COMPRESS_LZO; + else if (type == BTRFS_COMPRESS_ZSTD) + em->flags |= EXTENT_FLAG_COMPRESS_ZSTD; +} + +static inline enum btrfs_compression_type btrfs_extent_map_compression( + const struct extent_map *em) +{ + if (em->flags & EXTENT_FLAG_COMPRESS_ZLIB) + return BTRFS_COMPRESS_ZLIB; + + if (em->flags & EXTENT_FLAG_COMPRESS_LZO) + return BTRFS_COMPRESS_LZO; + + if (em->flags & EXTENT_FLAG_COMPRESS_ZSTD) + return BTRFS_COMPRESS_ZSTD; + + return BTRFS_COMPRESS_NONE; +} + +/* + * More efficient way to determine if extent is compressed, instead of using + * 'extent_map_compression() != BTRFS_COMPRESS_NONE'. + */ +static inline bool btrfs_extent_map_is_compressed(const struct extent_map *em) +{ + return (em->flags & (EXTENT_FLAG_COMPRESS_ZLIB | + EXTENT_FLAG_COMPRESS_LZO | + EXTENT_FLAG_COMPRESS_ZSTD)) != 0; +} + +static inline int btrfs_extent_map_in_tree(const struct extent_map *em) +{ + return !RB_EMPTY_NODE(&em->rb_node); +} + +static inline u64 btrfs_extent_map_block_start(const struct extent_map *em) +{ + if (em->disk_bytenr < EXTENT_MAP_LAST_BYTE) { + if (btrfs_extent_map_is_compressed(em)) + return em->disk_bytenr; + return em->disk_bytenr + em->offset; + } + return em->disk_bytenr; +} + +static inline u64 btrfs_extent_map_end(const struct extent_map *em) +{ + if (em->start + em->len < em->start) + return (u64)-1; + return em->start + em->len; +} + +void btrfs_extent_map_tree_init(struct extent_map_tree *tree); +struct extent_map *btrfs_lookup_extent_mapping(struct extent_map_tree *tree, + u64 start, u64 len); +void btrfs_remove_extent_mapping(struct btrfs_inode *inode, struct extent_map *em); +int btrfs_split_extent_map(struct btrfs_inode *inode, u64 start, u64 len, u64 pre, + u64 new_logical); + +struct extent_map *btrfs_alloc_extent_map(void); +void btrfs_free_extent_map(struct extent_map *em); +int __init btrfs_extent_map_init(void); +void __cold btrfs_extent_map_exit(void); +int btrfs_unpin_extent_cache(struct btrfs_inode *inode, u64 start, u64 len, u64 gen); +void btrfs_clear_em_logging(struct btrfs_inode *inode, struct extent_map *em); +struct extent_map *btrfs_search_extent_mapping(struct extent_map_tree *tree, + u64 start, u64 len); +int btrfs_add_extent_mapping(struct btrfs_inode *inode, + struct extent_map **em_in, u64 start, u64 len); +void btrfs_drop_extent_map_range(struct btrfs_inode *inode, + u64 start, u64 end, + bool skip_pinned); +int btrfs_replace_extent_map_range(struct btrfs_inode *inode, + struct extent_map *new_em, + bool modified); +void btrfs_free_extent_maps(struct btrfs_fs_info *fs_info, long nr_to_scan); +void btrfs_init_extent_map_shrinker_work(struct btrfs_fs_info *fs_info); + +#endif |