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31153d81 YZ |
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 | ||
19 | #include <linux/sched.h> | |
20 | #include "ctree.h" | |
21 | #include "ref-cache.h" | |
22 | #include "transaction.h" | |
23 | ||
24 | struct btrfs_leaf_ref *btrfs_alloc_leaf_ref(int nr_extents) | |
25 | { | |
26 | struct btrfs_leaf_ref *ref; | |
27 | ||
28 | ref = kmalloc(btrfs_leaf_ref_size(nr_extents), GFP_NOFS); | |
29 | if (ref) { | |
30 | memset(ref, 0, sizeof(*ref)); | |
31 | atomic_set(&ref->usage, 1); | |
017e5369 | 32 | INIT_LIST_HEAD(&ref->list); |
31153d81 YZ |
33 | } |
34 | return ref; | |
35 | } | |
36 | ||
37 | void btrfs_free_leaf_ref(struct btrfs_leaf_ref *ref) | |
38 | { | |
39 | if (!ref) | |
40 | return; | |
41 | WARN_ON(atomic_read(&ref->usage) == 0); | |
42 | if (atomic_dec_and_test(&ref->usage)) { | |
43 | BUG_ON(ref->in_tree); | |
44 | kfree(ref); | |
45 | } | |
46 | } | |
47 | ||
017e5369 | 48 | static struct rb_node *tree_insert(struct rb_root *root, u64 bytenr, |
31153d81 YZ |
49 | struct rb_node *node) |
50 | { | |
51 | struct rb_node ** p = &root->rb_node; | |
52 | struct rb_node * parent = NULL; | |
53 | struct btrfs_leaf_ref *entry; | |
31153d81 YZ |
54 | |
55 | while(*p) { | |
56 | parent = *p; | |
57 | entry = rb_entry(parent, struct btrfs_leaf_ref, rb_node); | |
58 | WARN_ON(!entry->in_tree); | |
59 | ||
017e5369 | 60 | if (bytenr < entry->bytenr) |
31153d81 | 61 | p = &(*p)->rb_left; |
017e5369 | 62 | else if (bytenr > entry->bytenr) |
31153d81 YZ |
63 | p = &(*p)->rb_right; |
64 | else | |
65 | return parent; | |
66 | } | |
67 | ||
68 | entry = rb_entry(node, struct btrfs_leaf_ref, rb_node); | |
69 | entry->in_tree = 1; | |
70 | rb_link_node(node, parent, p); | |
71 | rb_insert_color(node, root); | |
72 | return NULL; | |
73 | } | |
74 | ||
017e5369 | 75 | static struct rb_node *tree_search(struct rb_root *root, u64 bytenr) |
31153d81 YZ |
76 | { |
77 | struct rb_node * n = root->rb_node; | |
78 | struct btrfs_leaf_ref *entry; | |
31153d81 YZ |
79 | |
80 | while(n) { | |
81 | entry = rb_entry(n, struct btrfs_leaf_ref, rb_node); | |
82 | WARN_ON(!entry->in_tree); | |
83 | ||
017e5369 | 84 | if (bytenr < entry->bytenr) |
31153d81 | 85 | n = n->rb_left; |
017e5369 | 86 | else if (bytenr > entry->bytenr) |
31153d81 YZ |
87 | n = n->rb_right; |
88 | else | |
89 | return n; | |
90 | } | |
91 | return NULL; | |
92 | } | |
93 | ||
94 | int btrfs_remove_leaf_refs(struct btrfs_root *root) | |
95 | { | |
96 | struct rb_node *rb; | |
97 | struct btrfs_leaf_ref *ref = NULL; | |
98 | struct btrfs_leaf_ref_tree *tree = root->ref_tree; | |
99 | ||
100 | if (!tree) | |
101 | return 0; | |
102 | ||
103 | spin_lock(&tree->lock); | |
104 | while(!btrfs_leaf_ref_tree_empty(tree)) { | |
31153d81 YZ |
105 | rb = rb_first(&tree->root); |
106 | ref = rb_entry(rb, struct btrfs_leaf_ref, rb_node); | |
107 | rb_erase(&ref->rb_node, &tree->root); | |
108 | ref->in_tree = 0; | |
017e5369 | 109 | list_del_init(&ref->list); |
31153d81 YZ |
110 | |
111 | spin_unlock(&tree->lock); | |
112 | ||
113 | btrfs_free_leaf_ref(ref); | |
114 | ||
115 | cond_resched(); | |
116 | spin_lock(&tree->lock); | |
117 | } | |
118 | spin_unlock(&tree->lock); | |
119 | return 0; | |
120 | } | |
121 | ||
122 | struct btrfs_leaf_ref *btrfs_lookup_leaf_ref(struct btrfs_root *root, | |
017e5369 | 123 | u64 bytenr) |
31153d81 YZ |
124 | { |
125 | struct rb_node *rb; | |
126 | struct btrfs_leaf_ref *ref = NULL; | |
127 | struct btrfs_leaf_ref_tree *tree = root->ref_tree; | |
128 | ||
129 | if (!tree) | |
130 | return NULL; | |
131 | ||
132 | spin_lock(&tree->lock); | |
017e5369 CM |
133 | rb = tree_search(&tree->root, bytenr); |
134 | if (rb) | |
135 | ref = rb_entry(rb, struct btrfs_leaf_ref, rb_node); | |
31153d81 YZ |
136 | if (ref) |
137 | atomic_inc(&ref->usage); | |
138 | spin_unlock(&tree->lock); | |
139 | return ref; | |
140 | } | |
141 | ||
142 | int btrfs_add_leaf_ref(struct btrfs_root *root, struct btrfs_leaf_ref *ref) | |
143 | { | |
144 | int ret = 0; | |
145 | struct rb_node *rb; | |
146 | size_t size = btrfs_leaf_ref_size(ref->nritems); | |
147 | struct btrfs_leaf_ref_tree *tree = root->ref_tree; | |
31153d81 YZ |
148 | |
149 | spin_lock(&tree->lock); | |
017e5369 | 150 | rb = tree_insert(&tree->root, ref->bytenr, &ref->rb_node); |
31153d81 YZ |
151 | if (rb) { |
152 | ret = -EEXIST; | |
153 | } else { | |
154 | spin_lock(&root->fs_info->ref_cache_lock); | |
155 | root->fs_info->total_ref_cache_size += size; | |
31153d81 | 156 | spin_unlock(&root->fs_info->ref_cache_lock); |
31153d81 | 157 | atomic_inc(&ref->usage); |
017e5369 | 158 | list_add_tail(&ref->list, &tree->list); |
31153d81 YZ |
159 | } |
160 | spin_unlock(&tree->lock); | |
161 | return ret; | |
162 | } | |
163 | ||
164 | int btrfs_remove_leaf_ref(struct btrfs_root *root, struct btrfs_leaf_ref *ref) | |
165 | { | |
166 | size_t size = btrfs_leaf_ref_size(ref->nritems); | |
167 | struct btrfs_leaf_ref_tree *tree = root->ref_tree; | |
31153d81 YZ |
168 | |
169 | BUG_ON(!ref->in_tree); | |
170 | spin_lock(&tree->lock); | |
171 | ||
172 | spin_lock(&root->fs_info->ref_cache_lock); | |
173 | root->fs_info->total_ref_cache_size -= size; | |
31153d81 YZ |
174 | spin_unlock(&root->fs_info->ref_cache_lock); |
175 | ||
31153d81 YZ |
176 | rb_erase(&ref->rb_node, &tree->root); |
177 | ref->in_tree = 0; | |
017e5369 | 178 | list_del_init(&ref->list); |
31153d81 YZ |
179 | |
180 | spin_unlock(&tree->lock); | |
181 | ||
182 | btrfs_free_leaf_ref(ref); | |
183 | return 0; | |
184 | } | |
185 |