Commit | Line | Data |
---|---|---|
d1310b2e | 1 | #include <linux/err.h> |
a52d9a80 | 2 | #include <linux/gfp.h> |
d1310b2e | 3 | #include <linux/slab.h> |
a52d9a80 CM |
4 | #include <linux/module.h> |
5 | #include <linux/spinlock.h> | |
0a2118df | 6 | #include <linux/version.h> |
d1310b2e | 7 | #include <linux/hardirq.h> |
a52d9a80 CM |
8 | #include "extent_map.h" |
9 | ||
86479a04 CM |
10 | /* temporary define until extent_map moves out of btrfs */ |
11 | struct kmem_cache *btrfs_cache_create(const char *name, size_t size, | |
12 | unsigned long extra_flags, | |
13 | void (*ctor)(void *, struct kmem_cache *, | |
14 | unsigned long)); | |
15 | ||
a52d9a80 | 16 | static struct kmem_cache *extent_map_cache; |
ca664626 | 17 | |
2f4cbe64 | 18 | int __init extent_map_init(void) |
a52d9a80 | 19 | { |
86479a04 | 20 | extent_map_cache = btrfs_cache_create("extent_map", |
6d36dcd4 | 21 | sizeof(struct extent_map), 0, |
a52d9a80 | 22 | NULL); |
2f4cbe64 WB |
23 | if (!extent_map_cache) |
24 | return -ENOMEM; | |
2f4cbe64 | 25 | return 0; |
a52d9a80 CM |
26 | } |
27 | ||
17636e03 | 28 | void extent_map_exit(void) |
a52d9a80 | 29 | { |
a52d9a80 CM |
30 | if (extent_map_cache) |
31 | kmem_cache_destroy(extent_map_cache); | |
a52d9a80 CM |
32 | } |
33 | ||
9d2423c5 CH |
34 | /** |
35 | * extent_map_tree_init - initialize extent map tree | |
36 | * @tree: tree to initialize | |
37 | * @mask: flags for memory allocations during tree operations | |
38 | * | |
39 | * Initialize the extent tree @tree. Should be called for each new inode | |
40 | * or other user of the extent_map interface. | |
41 | */ | |
d1310b2e | 42 | void extent_map_tree_init(struct extent_map_tree *tree, gfp_t mask) |
a52d9a80 CM |
43 | { |
44 | tree->map.rb_node = NULL; | |
d1310b2e CM |
45 | tree->last = NULL; |
46 | spin_lock_init(&tree->lock); | |
a52d9a80 CM |
47 | } |
48 | EXPORT_SYMBOL(extent_map_tree_init); | |
49 | ||
9d2423c5 CH |
50 | /** |
51 | * alloc_extent_map - allocate new extent map structure | |
52 | * @mask: memory allocation flags | |
53 | * | |
54 | * Allocate a new extent_map structure. The new structure is | |
55 | * returned with a reference count of one and needs to be | |
56 | * freed using free_extent_map() | |
57 | */ | |
a52d9a80 CM |
58 | struct extent_map *alloc_extent_map(gfp_t mask) |
59 | { | |
60 | struct extent_map *em; | |
61 | em = kmem_cache_alloc(extent_map_cache, mask); | |
62 | if (!em || IS_ERR(em)) | |
63 | return em; | |
64 | em->in_tree = 0; | |
d1310b2e | 65 | em->flags = 0; |
a52d9a80 CM |
66 | atomic_set(&em->refs, 1); |
67 | return em; | |
68 | } | |
69 | EXPORT_SYMBOL(alloc_extent_map); | |
70 | ||
9d2423c5 CH |
71 | /** |
72 | * free_extent_map - drop reference count of an extent_map | |
73 | * @em: extent map beeing releasead | |
74 | * | |
75 | * Drops the reference out on @em by one and free the structure | |
76 | * if the reference count hits zero. | |
77 | */ | |
a52d9a80 CM |
78 | void free_extent_map(struct extent_map *em) |
79 | { | |
2bf5a725 CM |
80 | if (!em) |
81 | return; | |
d1310b2e | 82 | WARN_ON(atomic_read(&em->refs) == 0); |
a52d9a80 CM |
83 | if (atomic_dec_and_test(&em->refs)) { |
84 | WARN_ON(em->in_tree); | |
85 | kmem_cache_free(extent_map_cache, em); | |
86 | } | |
87 | } | |
88 | EXPORT_SYMBOL(free_extent_map); | |
89 | ||
a52d9a80 CM |
90 | static struct rb_node *tree_insert(struct rb_root *root, u64 offset, |
91 | struct rb_node *node) | |
92 | { | |
93 | struct rb_node ** p = &root->rb_node; | |
94 | struct rb_node * parent = NULL; | |
d1310b2e | 95 | struct extent_map *entry; |
a52d9a80 CM |
96 | |
97 | while(*p) { | |
98 | parent = *p; | |
d1310b2e CM |
99 | entry = rb_entry(parent, struct extent_map, rb_node); |
100 | ||
101 | WARN_ON(!entry->in_tree); | |
a52d9a80 CM |
102 | |
103 | if (offset < entry->start) | |
104 | p = &(*p)->rb_left; | |
d1310b2e | 105 | else if (offset >= extent_map_end(entry)) |
a52d9a80 CM |
106 | p = &(*p)->rb_right; |
107 | else | |
108 | return parent; | |
109 | } | |
110 | ||
d1310b2e | 111 | entry = rb_entry(node, struct extent_map, rb_node); |
a52d9a80 CM |
112 | entry->in_tree = 1; |
113 | rb_link_node(node, parent, p); | |
114 | rb_insert_color(node, root); | |
115 | return NULL; | |
116 | } | |
117 | ||
118 | static struct rb_node *__tree_search(struct rb_root *root, u64 offset, | |
5f56406a CM |
119 | struct rb_node **prev_ret, |
120 | struct rb_node **next_ret) | |
a52d9a80 CM |
121 | { |
122 | struct rb_node * n = root->rb_node; | |
123 | struct rb_node *prev = NULL; | |
5f56406a | 124 | struct rb_node *orig_prev = NULL; |
d1310b2e CM |
125 | struct extent_map *entry; |
126 | struct extent_map *prev_entry = NULL; | |
a52d9a80 CM |
127 | |
128 | while(n) { | |
d1310b2e | 129 | entry = rb_entry(n, struct extent_map, rb_node); |
a52d9a80 CM |
130 | prev = n; |
131 | prev_entry = entry; | |
132 | ||
d1310b2e CM |
133 | WARN_ON(!entry->in_tree); |
134 | ||
a52d9a80 CM |
135 | if (offset < entry->start) |
136 | n = n->rb_left; | |
d1310b2e | 137 | else if (offset >= extent_map_end(entry)) |
a52d9a80 CM |
138 | n = n->rb_right; |
139 | else | |
140 | return n; | |
141 | } | |
5f56406a CM |
142 | |
143 | if (prev_ret) { | |
144 | orig_prev = prev; | |
d1310b2e | 145 | while(prev && offset >= extent_map_end(prev_entry)) { |
5f56406a | 146 | prev = rb_next(prev); |
d1310b2e | 147 | prev_entry = rb_entry(prev, struct extent_map, rb_node); |
5f56406a CM |
148 | } |
149 | *prev_ret = prev; | |
150 | prev = orig_prev; | |
151 | } | |
152 | ||
153 | if (next_ret) { | |
d1310b2e | 154 | prev_entry = rb_entry(prev, struct extent_map, rb_node); |
5f56406a CM |
155 | while(prev && offset < prev_entry->start) { |
156 | prev = rb_prev(prev); | |
d1310b2e | 157 | prev_entry = rb_entry(prev, struct extent_map, rb_node); |
5f56406a CM |
158 | } |
159 | *next_ret = prev; | |
a52d9a80 | 160 | } |
a52d9a80 CM |
161 | return NULL; |
162 | } | |
163 | ||
164 | static inline struct rb_node *tree_search(struct rb_root *root, u64 offset) | |
165 | { | |
166 | struct rb_node *prev; | |
167 | struct rb_node *ret; | |
5f56406a | 168 | ret = __tree_search(root, offset, &prev, NULL); |
a52d9a80 CM |
169 | if (!ret) |
170 | return prev; | |
171 | return ret; | |
172 | } | |
173 | ||
d1310b2e | 174 | static int mergable_maps(struct extent_map *prev, struct extent_map *next) |
a52d9a80 | 175 | { |
d1310b2e CM |
176 | if (extent_map_end(prev) == next->start && |
177 | prev->flags == next->flags && | |
178 | prev->bdev == next->bdev && | |
179 | ((next->block_start == EXTENT_MAP_HOLE && | |
180 | prev->block_start == EXTENT_MAP_HOLE) || | |
181 | (next->block_start == EXTENT_MAP_INLINE && | |
182 | prev->block_start == EXTENT_MAP_INLINE) || | |
183 | (next->block_start == EXTENT_MAP_DELALLOC && | |
184 | prev->block_start == EXTENT_MAP_DELALLOC) || | |
185 | (next->block_start < EXTENT_MAP_LAST_BYTE - 1 && | |
186 | next->block_start == extent_map_block_end(prev)))) { | |
187 | return 1; | |
188 | } | |
a52d9a80 CM |
189 | return 0; |
190 | } | |
191 | ||
9d2423c5 CH |
192 | /** |
193 | * add_extent_mapping - add new extent map to the extent tree | |
194 | * @tree: tree to insert new map in | |
195 | * @em: map to insert | |
196 | * | |
197 | * Insert @em into @tree or perform a simple forward/backward merge with | |
198 | * existing mappings. The extent_map struct passed in will be inserted | |
199 | * into the tree directly, with an additional reference taken, or a | |
200 | * reference dropped if the merge attempt was sucessfull. | |
a52d9a80 CM |
201 | */ |
202 | int add_extent_mapping(struct extent_map_tree *tree, | |
203 | struct extent_map *em) | |
204 | { | |
205 | int ret = 0; | |
d1310b2e | 206 | struct extent_map *merge = NULL; |
a52d9a80 CM |
207 | struct rb_node *rb; |
208 | ||
d1310b2e | 209 | rb = tree_insert(&tree->map, em->start, &em->rb_node); |
a52d9a80 | 210 | if (rb) { |
d1310b2e | 211 | merge = rb_entry(rb, struct extent_map, rb_node); |
a52d9a80 CM |
212 | ret = -EEXIST; |
213 | goto out; | |
214 | } | |
215 | atomic_inc(&em->refs); | |
216 | if (em->start != 0) { | |
217 | rb = rb_prev(&em->rb_node); | |
218 | if (rb) | |
d1310b2e CM |
219 | merge = rb_entry(rb, struct extent_map, rb_node); |
220 | if (rb && mergable_maps(merge, em)) { | |
221 | em->start = merge->start; | |
222 | em->len += merge->len; | |
223 | em->block_start = merge->block_start; | |
224 | merge->in_tree = 0; | |
225 | rb_erase(&merge->rb_node, &tree->map); | |
226 | free_extent_map(merge); | |
a52d9a80 CM |
227 | } |
228 | } | |
d1310b2e CM |
229 | rb = rb_next(&em->rb_node); |
230 | if (rb) | |
231 | merge = rb_entry(rb, struct extent_map, rb_node); | |
232 | if (rb && mergable_maps(em, merge)) { | |
233 | em->len += merge->len; | |
234 | rb_erase(&merge->rb_node, &tree->map); | |
235 | merge->in_tree = 0; | |
236 | free_extent_map(merge); | |
237 | } | |
238 | tree->last = em; | |
a52d9a80 | 239 | out: |
a52d9a80 CM |
240 | return ret; |
241 | } | |
242 | EXPORT_SYMBOL(add_extent_mapping); | |
243 | ||
d1310b2e CM |
244 | static u64 range_end(u64 start, u64 len) |
245 | { | |
246 | if (start + len < start) | |
247 | return (u64)-1; | |
248 | return start + len; | |
249 | } | |
250 | ||
9d2423c5 CH |
251 | /** |
252 | * lookup_extent_mapping - lookup extent_map | |
253 | * @tree: tree to lookup in | |
254 | * @start: byte offset to start the search | |
255 | * @len: length of the lookup range | |
256 | * | |
257 | * Find and return the first extent_map struct in @tree that intersects the | |
258 | * [start, len] range. There may be additional objects in the tree that | |
259 | * intersect, so check the object returned carefully to make sure that no | |
260 | * additional lookups are needed. | |
a52d9a80 CM |
261 | */ |
262 | struct extent_map *lookup_extent_mapping(struct extent_map_tree *tree, | |
d1310b2e | 263 | u64 start, u64 len) |
a52d9a80 CM |
264 | { |
265 | struct extent_map *em; | |
266 | struct rb_node *rb_node; | |
306929f3 CH |
267 | struct rb_node *prev = NULL; |
268 | struct rb_node *next = NULL; | |
269 | u64 end = range_end(start, len); | |
270 | ||
271 | em = tree->last; | |
272 | if (em && end > em->start && start < extent_map_end(em)) | |
273 | goto found; | |
a52d9a80 | 274 | |
5f56406a CM |
275 | rb_node = __tree_search(&tree->map, start, &prev, &next); |
276 | if (!rb_node && prev) { | |
277 | em = rb_entry(prev, struct extent_map, rb_node); | |
d1310b2e | 278 | if (end > em->start && start < extent_map_end(em)) |
5f56406a CM |
279 | goto found; |
280 | } | |
281 | if (!rb_node && next) { | |
282 | em = rb_entry(next, struct extent_map, rb_node); | |
d1310b2e | 283 | if (end > em->start && start < extent_map_end(em)) |
5f56406a CM |
284 | goto found; |
285 | } | |
a52d9a80 CM |
286 | if (!rb_node) { |
287 | em = NULL; | |
288 | goto out; | |
289 | } | |
290 | if (IS_ERR(rb_node)) { | |
291 | em = ERR_PTR(PTR_ERR(rb_node)); | |
292 | goto out; | |
293 | } | |
294 | em = rb_entry(rb_node, struct extent_map, rb_node); | |
d1310b2e CM |
295 | if (end > em->start && start < extent_map_end(em)) |
296 | goto found; | |
297 | ||
298 | em = NULL; | |
299 | goto out; | |
300 | ||
5f56406a | 301 | found: |
a52d9a80 | 302 | atomic_inc(&em->refs); |
d1310b2e | 303 | tree->last = em; |
a52d9a80 | 304 | out: |
a52d9a80 CM |
305 | return em; |
306 | } | |
307 | EXPORT_SYMBOL(lookup_extent_mapping); | |
308 | ||
9d2423c5 CH |
309 | /** |
310 | * remove_extent_mapping - removes an extent_map from the extent tree | |
311 | * @tree: extent tree to remove from | |
312 | * @em: extent map beeing removed | |
313 | * | |
314 | * Removes @em from @tree. No reference counts are dropped, and no checks | |
315 | * are done to see if the range is in use | |
a52d9a80 CM |
316 | */ |
317 | int remove_extent_mapping(struct extent_map_tree *tree, struct extent_map *em) | |
318 | { | |
d1310b2e | 319 | int ret = 0; |
a52d9a80 | 320 | |
d1310b2e CM |
321 | rb_erase(&em->rb_node, &tree->map); |
322 | em->in_tree = 0; | |
323 | if (tree->last == em) | |
324 | tree->last = NULL; | |
a52d9a80 CM |
325 | return ret; |
326 | } | |
327 | EXPORT_SYMBOL(remove_extent_mapping); |