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c3e14909d3
This is a preparatory patch for removing extent_map::bdev. There's some
history behind the code so this is only precaution to catch if things
break before the actual removal happens.
Logically, comparing a raw low-level block device (bdev) does not make
sense for extent maps (high-level objects). This had no effect in
practice but was quite confusing in the code. The lookup_map is set iff
EXTENT_FLAG_FS_MAPPING is set.
The two pointers were stored in the same bytes and used potentially in
two meanings. Now they're split, so the asserts are in place to check
that the condition will not change.
The lookup map pointer misused bdev, this has been changed in commit
95617d6932 ("btrfs: cleanup, stop casting for extent_map->lookup
everywhere") to the explicit type. But the semantics hasn't changed and
bdev was not actually used to decide if maps are mergeable.
Signed-off-by: David Sterba <dsterba@suse.com>
107 lines
2.7 KiB
C
107 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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/* used only during fiemap calls */
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#define EXTENT_MAP_DELALLOC ((u64)-1)
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/* bits for the extent_map::flags field */
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enum {
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/* this entry not yet on disk, don't free it */
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EXTENT_FLAG_PINNED,
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EXTENT_FLAG_COMPRESSED,
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/* pre-allocated extent */
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EXTENT_FLAG_PREALLOC,
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/* Logging this extent */
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EXTENT_FLAG_LOGGING,
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/* Filling in a preallocated extent */
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EXTENT_FLAG_FILLING,
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/* filesystem extent mapping type */
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EXTENT_FLAG_FS_MAPPING,
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};
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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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struct {
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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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