Root/fs/btrfs/ref-cache.h

1/*
2 * Copyright (C) 2008 Oracle. All rights reserved.
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public
6 * License v2 as published by the Free Software Foundation.
7 *
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
11 * General Public License for more details.
12 *
13 * You should have received a copy of the GNU General Public
14 * License along with this program; if not, write to the
15 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
16 * Boston, MA 021110-1307, USA.
17 */
18#ifndef __REFCACHE__
19#define __REFCACHE__
20
21struct btrfs_extent_info {
22    /* bytenr and num_bytes find the extent in the extent allocation tree */
23    u64 bytenr;
24    u64 num_bytes;
25
26    /* objectid and offset find the back reference for the file */
27    u64 objectid;
28    u64 offset;
29};
30
31struct btrfs_leaf_ref {
32    struct rb_node rb_node;
33    struct btrfs_leaf_ref_tree *tree;
34    int in_tree;
35    atomic_t usage;
36
37    u64 root_gen;
38    u64 bytenr;
39    u64 owner;
40    u64 generation;
41    int nritems;
42
43    struct list_head list;
44    struct btrfs_extent_info extents[];
45};
46
47static inline size_t btrfs_leaf_ref_size(int nr_extents)
48{
49    return sizeof(struct btrfs_leaf_ref) +
50           sizeof(struct btrfs_extent_info) * nr_extents;
51}
52
53static inline void btrfs_leaf_ref_tree_init(struct btrfs_leaf_ref_tree *tree)
54{
55    tree->root = RB_ROOT;
56    INIT_LIST_HEAD(&tree->list);
57    spin_lock_init(&tree->lock);
58}
59
60static inline int btrfs_leaf_ref_tree_empty(struct btrfs_leaf_ref_tree *tree)
61{
62    return RB_EMPTY_ROOT(&tree->root);
63}
64
65void btrfs_leaf_ref_tree_init(struct btrfs_leaf_ref_tree *tree);
66struct btrfs_leaf_ref *btrfs_alloc_leaf_ref(struct btrfs_root *root,
67                        int nr_extents);
68void btrfs_free_leaf_ref(struct btrfs_root *root, struct btrfs_leaf_ref *ref);
69struct btrfs_leaf_ref *btrfs_lookup_leaf_ref(struct btrfs_root *root,
70                         u64 bytenr);
71int btrfs_add_leaf_ref(struct btrfs_root *root, struct btrfs_leaf_ref *ref,
72               int shared);
73int btrfs_remove_leaf_refs(struct btrfs_root *root, u64 max_root_gen,
74               int shared);
75int btrfs_remove_leaf_ref(struct btrfs_root *root, struct btrfs_leaf_ref *ref);
76#endif
77

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