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/* 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 "misc.h"
#include "compression.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 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 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 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 extent_map_in_tree(const struct extent_map *em)
{
return !RB_EMPTY_NODE(&em->rb_node);
}
static inline u64 extent_map_block_start(const struct extent_map *em)
{
if (em->disk_bytenr < EXTENT_MAP_LAST_BYTE) {
if (extent_map_is_compressed(em))
return em->disk_bytenr;
return em->disk_bytenr + em->offset;
}
return em->disk_bytenr;
}
static inline u64 extent_map_end(const struct extent_map *em)
{
if (em->start + em->len < em->start)
return (u64)-1;
return em->start + em->len;
}
void extent_map_tree_init(struct extent_map_tree *tree);
struct extent_map *lookup_extent_mapping(struct extent_map_tree *tree,
u64 start, u64 len);
void remove_extent_mapping(struct btrfs_inode *inode, struct extent_map *em);
int split_extent_map(struct btrfs_inode *inode, u64 start, u64 len, u64 pre,
u64 new_logical);
struct extent_map *alloc_extent_map(void);
void free_extent_map(struct extent_map *em);
int __init extent_map_init(void);
void __cold extent_map_exit(void);
int unpin_extent_cache(struct btrfs_inode *inode, u64 start, u64 len, u64 gen);
void clear_em_logging(struct btrfs_inode *inode, struct extent_map *em);
struct extent_map *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);
long btrfs_free_extent_maps(struct btrfs_fs_info *fs_info, long nr_to_scan);
#endif
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