diff options
Diffstat (limited to 'fs/btrfs/ref-cache.c')
-rw-r--r-- | fs/btrfs/ref-cache.c | 164 |
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 | */ | ||
36 | struct 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 | */ | ||
59 | void 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 | |||
76 | static struct rb_node *tree_insert(struct rb_root *root, u64 bytenr, | 26 | static 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 | |||
120 | int 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 | */ | ||
158 | struct 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; | ||
164 | again: | ||
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 | */ | ||
187 | int 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 | */ | ||
215 | int 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 | } | ||