diff options
Diffstat (limited to 'fs/btrfs/extent_map.h')
| -rw-r--r-- | fs/btrfs/extent_map.h | 67 |
1 files changed, 58 insertions, 9 deletions
diff --git a/fs/btrfs/extent_map.h b/fs/btrfs/extent_map.h index c5a098c99c..6d587111f7 100644 --- a/fs/btrfs/extent_map.h +++ b/fs/btrfs/extent_map.h @@ -30,28 +30,77 @@ enum { ENUM_BIT(EXTENT_FLAG_PREALLOC), /* Logging this extent */ ENUM_BIT(EXTENT_FLAG_LOGGING), - /* Filling in a preallocated extent */ - ENUM_BIT(EXTENT_FLAG_FILLING), /* 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 */ + /* 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; - u64 mod_start; - u64 mod_len; + + /* + * The file offset of the original file extent before splitting. + * + * This is an in-memory only member, matching + * extent_map::start - btrfs_file_extent_item::offset for + * regular/preallocated extents. EXTENT_MAP_HOLE otherwise. + */ u64 orig_start; + + /* + * The full on-disk extent length, matching + * btrfs_file_extent_item::disk_num_bytes. + */ u64 orig_block_len; + + /* + * The decompressed size of the whole on-disk extent, matching + * btrfs_file_extent_item::ram_bytes. + */ u64 ram_bytes; + + /* + * The on-disk logical bytenr for the file extent. + * + * For compressed extents it matches btrfs_file_extent_item::disk_bytenr. + * For uncompressed extents it matches + * btrfs_file_extent_item::disk_bytenr + btrfs_file_extent_item::offset + * + * For holes it is EXTENT_MAP_HOLE and for inline extents it is + * EXTENT_MAP_INLINE. + */ u64 block_start; + + /* + * The on-disk length for the file extent. + * + * For compressed extents it matches btrfs_file_extent_item::disk_num_bytes. + * For uncompressed extents it matches extent_map::len. + * For holes and inline extents it's -1 and shouldn't be used. + */ u64 block_len; /* @@ -124,7 +173,7 @@ static inline u64 extent_map_end(const struct extent_map *em) 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 extent_map_tree *tree, struct extent_map *em); +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); @@ -133,11 +182,10 @@ 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 extent_map_tree *tree, struct extent_map *em); +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_fs_info *fs_info, - struct extent_map_tree *em_tree, +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, @@ -145,5 +193,6 @@ void btrfs_drop_extent_map_range(struct btrfs_inode *inode, 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 |