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07e1ce096d
rb_first_cached() trades an extra pointer "leftmost" for doing the same job as rb_first() but in O(1). As evict_inode_truncate_pages() removes all extent mapping by always looking for the first rb entry, it's helpful to use rb_first_cached instead. For more details about the optimization see patch "Btrfs: delayed-refs: use rb_first_cached for href_root". Tested-by: Holger Hoffstätte <holger@applied-asynchrony.com> Signed-off-by: Liu Bo <bo.liu@linux.alibaba.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
99 lines
2.7 KiB
C
99 lines
2.7 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef BTRFS_EXTENT_MAP_H
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#define BTRFS_EXTENT_MAP_H
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#include <linux/rbtree.h>
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#include <linux/refcount.h>
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#define EXTENT_MAP_LAST_BYTE ((u64)-4)
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#define EXTENT_MAP_HOLE ((u64)-3)
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#define EXTENT_MAP_INLINE ((u64)-2)
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#define EXTENT_MAP_DELALLOC ((u64)-1)
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/* bits for the flags field */
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#define EXTENT_FLAG_PINNED 0 /* this entry not yet on disk, don't free it */
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#define EXTENT_FLAG_COMPRESSED 1
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#define EXTENT_FLAG_PREALLOC 3 /* pre-allocated extent */
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#define EXTENT_FLAG_LOGGING 4 /* Logging this extent */
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#define EXTENT_FLAG_FILLING 5 /* Filling in a preallocated extent */
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#define EXTENT_FLAG_FS_MAPPING 6 /* filesystem extent mapping type */
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struct extent_map {
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struct rb_node rb_node;
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/* all of these are in bytes */
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u64 start;
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u64 len;
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u64 mod_start;
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u64 mod_len;
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u64 orig_start;
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u64 orig_block_len;
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u64 ram_bytes;
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u64 block_start;
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u64 block_len;
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u64 generation;
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unsigned long flags;
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union {
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struct block_device *bdev;
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/*
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* used for chunk mappings
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* flags & EXTENT_FLAG_FS_MAPPING must be set
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*/
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struct map_lookup *map_lookup;
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};
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refcount_t refs;
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unsigned int compress_type;
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struct list_head list;
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};
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struct extent_map_tree {
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struct rb_root_cached map;
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struct list_head modified_extents;
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rwlock_t lock;
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};
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static inline int extent_map_in_tree(const struct extent_map *em)
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{
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return !RB_EMPTY_NODE(&em->rb_node);
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}
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static inline u64 extent_map_end(struct extent_map *em)
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{
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if (em->start + em->len < em->start)
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return (u64)-1;
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return em->start + em->len;
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}
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static inline u64 extent_map_block_end(struct extent_map *em)
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{
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if (em->block_start + em->block_len < em->block_start)
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return (u64)-1;
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return em->block_start + em->block_len;
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}
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void extent_map_tree_init(struct extent_map_tree *tree);
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struct extent_map *lookup_extent_mapping(struct extent_map_tree *tree,
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u64 start, u64 len);
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int add_extent_mapping(struct extent_map_tree *tree,
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struct extent_map *em, int modified);
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void remove_extent_mapping(struct extent_map_tree *tree, struct extent_map *em);
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void replace_extent_mapping(struct extent_map_tree *tree,
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struct extent_map *cur,
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struct extent_map *new,
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int modified);
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struct extent_map *alloc_extent_map(void);
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void free_extent_map(struct extent_map *em);
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int __init extent_map_init(void);
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void __cold extent_map_exit(void);
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int unpin_extent_cache(struct extent_map_tree *tree, u64 start, u64 len, u64 gen);
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void clear_em_logging(struct extent_map_tree *tree, struct extent_map *em);
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struct extent_map *search_extent_mapping(struct extent_map_tree *tree,
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u64 start, u64 len);
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int btrfs_add_extent_mapping(struct btrfs_fs_info *fs_info,
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struct extent_map_tree *em_tree,
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struct extent_map **em_in, u64 start, u64 len);
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#endif
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