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-rw-r--r--fs/btrfs/ref-cache.c164
1 files changed, 0 insertions, 164 deletions
diff --git a/fs/btrfs/ref-cache.c b/fs/btrfs/ref-cache.c
index a97314cf6bd..82d569cb626 100644
--- a/fs/btrfs/ref-cache.c
+++ b/fs/btrfs/ref-cache.c
@@ -23,56 +23,6 @@
23#include "ref-cache.h" 23#include "ref-cache.h"
24#include "transaction.h" 24#include "transaction.h"
25 25
26/*
27 * leaf refs are used to cache the information about which extents
28 * a given leaf has references on. This allows us to process that leaf
29 * in btrfs_drop_snapshot without needing to read it back from disk.
30 */
31
32/*
33 * kmalloc a leaf reference struct and update the counters for the
34 * total ref cache size
35 */
36struct btrfs_leaf_ref *btrfs_alloc_leaf_ref(struct btrfs_root *root,
37 int nr_extents)
38{
39 struct btrfs_leaf_ref *ref;
40 size_t size = btrfs_leaf_ref_size(nr_extents);
41
42 ref = kmalloc(size, GFP_NOFS);
43 if (ref) {
44 spin_lock(&root->fs_info->ref_cache_lock);
45 root->fs_info->total_ref_cache_size += size;
46 spin_unlock(&root->fs_info->ref_cache_lock);
47
48 memset(ref, 0, sizeof(*ref));
49 atomic_set(&ref->usage, 1);
50 INIT_LIST_HEAD(&ref->list);
51 }
52 return ref;
53}
54
55/*
56 * free a leaf reference struct and update the counters for the
57 * total ref cache size
58 */
59void btrfs_free_leaf_ref(struct btrfs_root *root, struct btrfs_leaf_ref *ref)
60{
61 if (!ref)
62 return;
63 WARN_ON(atomic_read(&ref->usage) == 0);
64 if (atomic_dec_and_test(&ref->usage)) {
65 size_t size = btrfs_leaf_ref_size(ref->nritems);
66
67 BUG_ON(ref->in_tree);
68 kfree(ref);
69
70 spin_lock(&root->fs_info->ref_cache_lock);
71 root->fs_info->total_ref_cache_size -= size;
72 spin_unlock(&root->fs_info->ref_cache_lock);
73 }
74}
75
76static struct rb_node *tree_insert(struct rb_root *root, u64 bytenr, 26static struct rb_node *tree_insert(struct rb_root *root, u64 bytenr,
77 struct rb_node *node) 27 struct rb_node *node)
78{ 28{
@@ -116,117 +66,3 @@ static struct rb_node *tree_search(struct rb_root *root, u64 bytenr)
116 } 66 }
117 return NULL; 67 return NULL;
118} 68}
119
120int btrfs_remove_leaf_refs(struct btrfs_root *root, u64 max_root_gen,
121 int shared)
122{
123 struct btrfs_leaf_ref *ref = NULL;
124 struct btrfs_leaf_ref_tree *tree = root->ref_tree;
125
126 if (shared)
127 tree = &root->fs_info->shared_ref_tree;
128 if (!tree)
129 return 0;
130
131 spin_lock(&tree->lock);
132 while (!list_empty(&tree->list)) {
133 ref = list_entry(tree->list.next, struct btrfs_leaf_ref, list);
134 BUG_ON(ref->tree != tree);
135 if (ref->root_gen > max_root_gen)
136 break;
137 if (!xchg(&ref->in_tree, 0)) {
138 cond_resched_lock(&tree->lock);
139 continue;
140 }
141
142 rb_erase(&ref->rb_node, &tree->root);
143 list_del_init(&ref->list);
144
145 spin_unlock(&tree->lock);
146 btrfs_free_leaf_ref(root, ref);
147 cond_resched();
148 spin_lock(&tree->lock);
149 }
150 spin_unlock(&tree->lock);
151 return 0;
152}
153
154/*
155 * find the leaf ref for a given extent. This returns the ref struct with
156 * a usage reference incremented
157 */
158struct btrfs_leaf_ref *btrfs_lookup_leaf_ref(struct btrfs_root *root,
159 u64 bytenr)
160{
161 struct rb_node *rb;
162 struct btrfs_leaf_ref *ref = NULL;
163 struct btrfs_leaf_ref_tree *tree = root->ref_tree;
164again:
165 if (tree) {
166 spin_lock(&tree->lock);
167 rb = tree_search(&tree->root, bytenr);
168 if (rb)
169 ref = rb_entry(rb, struct btrfs_leaf_ref, rb_node);
170 if (ref)
171 atomic_inc(&ref->usage);
172 spin_unlock(&tree->lock);
173 if (ref)
174 return ref;
175 }
176 if (tree != &root->fs_info->shared_ref_tree) {
177 tree = &root->fs_info->shared_ref_tree;
178 goto again;
179 }
180 return NULL;
181}
182
183/*
184 * add a fully filled in leaf ref struct
185 * remove all the refs older than a given root generation
186 */
187int btrfs_add_leaf_ref(struct btrfs_root *root, struct btrfs_leaf_ref *ref,
188 int shared)
189{
190 int ret = 0;
191 struct rb_node *rb;
192 struct btrfs_leaf_ref_tree *tree = root->ref_tree;
193
194 if (shared)
195 tree = &root->fs_info->shared_ref_tree;
196
197 spin_lock(&tree->lock);
198 rb = tree_insert(&tree->root, ref->bytenr, &ref->rb_node);
199 if (rb) {
200 ret = -EEXIST;
201 } else {
202 atomic_inc(&ref->usage);
203 ref->tree = tree;
204 ref->in_tree = 1;
205 list_add_tail(&ref->list, &tree->list);
206 }
207 spin_unlock(&tree->lock);
208 return ret;
209}
210
211/*
212 * remove a single leaf ref from the tree. This drops the ref held by the tree
213 * only
214 */
215int btrfs_remove_leaf_ref(struct btrfs_root *root, struct btrfs_leaf_ref *ref)
216{
217 struct btrfs_leaf_ref_tree *tree;
218
219 if (!xchg(&ref->in_tree, 0))
220 return 0;
221
222 tree = ref->tree;
223 spin_lock(&tree->lock);
224
225 rb_erase(&ref->rb_node, &tree->root);
226 list_del_init(&ref->list);
227
228 spin_unlock(&tree->lock);
229
230 btrfs_free_leaf_ref(root, ref);
231 return 0;
232}