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Commit | Line | Data |
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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 | 45 | spin_lock_init(&tree->lock); |
a52d9a80 CM |
46 | } |
47 | EXPORT_SYMBOL(extent_map_tree_init); | |
48 | ||
9d2423c5 CH |
49 | /** |
50 | * alloc_extent_map - allocate new extent map structure | |
51 | * @mask: memory allocation flags | |
52 | * | |
53 | * Allocate a new extent_map structure. The new structure is | |
54 | * returned with a reference count of one and needs to be | |
55 | * freed using free_extent_map() | |
56 | */ | |
a52d9a80 CM |
57 | struct extent_map *alloc_extent_map(gfp_t mask) |
58 | { | |
59 | struct extent_map *em; | |
60 | em = kmem_cache_alloc(extent_map_cache, mask); | |
61 | if (!em || IS_ERR(em)) | |
62 | return em; | |
63 | em->in_tree = 0; | |
d1310b2e | 64 | em->flags = 0; |
a52d9a80 CM |
65 | atomic_set(&em->refs, 1); |
66 | return em; | |
67 | } | |
68 | EXPORT_SYMBOL(alloc_extent_map); | |
69 | ||
9d2423c5 CH |
70 | /** |
71 | * free_extent_map - drop reference count of an extent_map | |
72 | * @em: extent map beeing releasead | |
73 | * | |
74 | * Drops the reference out on @em by one and free the structure | |
75 | * if the reference count hits zero. | |
76 | */ | |
a52d9a80 CM |
77 | void free_extent_map(struct extent_map *em) |
78 | { | |
2bf5a725 CM |
79 | if (!em) |
80 | return; | |
d1310b2e | 81 | WARN_ON(atomic_read(&em->refs) == 0); |
a52d9a80 CM |
82 | if (atomic_dec_and_test(&em->refs)) { |
83 | WARN_ON(em->in_tree); | |
84 | kmem_cache_free(extent_map_cache, em); | |
85 | } | |
86 | } | |
87 | EXPORT_SYMBOL(free_extent_map); | |
88 | ||
a52d9a80 CM |
89 | static struct rb_node *tree_insert(struct rb_root *root, u64 offset, |
90 | struct rb_node *node) | |
91 | { | |
92 | struct rb_node ** p = &root->rb_node; | |
93 | struct rb_node * parent = NULL; | |
d1310b2e | 94 | struct extent_map *entry; |
a52d9a80 CM |
95 | |
96 | while(*p) { | |
97 | parent = *p; | |
d1310b2e CM |
98 | entry = rb_entry(parent, struct extent_map, rb_node); |
99 | ||
100 | WARN_ON(!entry->in_tree); | |
a52d9a80 CM |
101 | |
102 | if (offset < entry->start) | |
103 | p = &(*p)->rb_left; | |
d1310b2e | 104 | else if (offset >= extent_map_end(entry)) |
a52d9a80 CM |
105 | p = &(*p)->rb_right; |
106 | else | |
107 | return parent; | |
108 | } | |
109 | ||
d1310b2e | 110 | entry = rb_entry(node, struct extent_map, rb_node); |
a52d9a80 CM |
111 | entry->in_tree = 1; |
112 | rb_link_node(node, parent, p); | |
113 | rb_insert_color(node, root); | |
114 | return NULL; | |
115 | } | |
116 | ||
d352ac68 CM |
117 | /* |
118 | * search through the tree for an extent_map with a given offset. If | |
119 | * it can't be found, try to find some neighboring extents | |
120 | */ | |
a52d9a80 | 121 | static struct rb_node *__tree_search(struct rb_root *root, u64 offset, |
5f56406a CM |
122 | struct rb_node **prev_ret, |
123 | struct rb_node **next_ret) | |
a52d9a80 CM |
124 | { |
125 | struct rb_node * n = root->rb_node; | |
126 | struct rb_node *prev = NULL; | |
5f56406a | 127 | struct rb_node *orig_prev = NULL; |
d1310b2e CM |
128 | struct extent_map *entry; |
129 | struct extent_map *prev_entry = NULL; | |
a52d9a80 CM |
130 | |
131 | while(n) { | |
d1310b2e | 132 | entry = rb_entry(n, struct extent_map, rb_node); |
a52d9a80 CM |
133 | prev = n; |
134 | prev_entry = entry; | |
135 | ||
d1310b2e CM |
136 | WARN_ON(!entry->in_tree); |
137 | ||
a52d9a80 CM |
138 | if (offset < entry->start) |
139 | n = n->rb_left; | |
d1310b2e | 140 | else if (offset >= extent_map_end(entry)) |
a52d9a80 CM |
141 | n = n->rb_right; |
142 | else | |
143 | return n; | |
144 | } | |
5f56406a CM |
145 | |
146 | if (prev_ret) { | |
147 | orig_prev = prev; | |
d1310b2e | 148 | while(prev && offset >= extent_map_end(prev_entry)) { |
5f56406a | 149 | prev = rb_next(prev); |
d1310b2e | 150 | prev_entry = rb_entry(prev, struct extent_map, rb_node); |
5f56406a CM |
151 | } |
152 | *prev_ret = prev; | |
153 | prev = orig_prev; | |
154 | } | |
155 | ||
156 | if (next_ret) { | |
d1310b2e | 157 | prev_entry = rb_entry(prev, struct extent_map, rb_node); |
5f56406a CM |
158 | while(prev && offset < prev_entry->start) { |
159 | prev = rb_prev(prev); | |
d1310b2e | 160 | prev_entry = rb_entry(prev, struct extent_map, rb_node); |
5f56406a CM |
161 | } |
162 | *next_ret = prev; | |
a52d9a80 | 163 | } |
a52d9a80 CM |
164 | return NULL; |
165 | } | |
166 | ||
d352ac68 CM |
167 | /* |
168 | * look for an offset in the tree, and if it can't be found, return | |
169 | * the first offset we can find smaller than 'offset'. | |
170 | */ | |
a52d9a80 CM |
171 | static inline struct rb_node *tree_search(struct rb_root *root, u64 offset) |
172 | { | |
173 | struct rb_node *prev; | |
174 | struct rb_node *ret; | |
5f56406a | 175 | ret = __tree_search(root, offset, &prev, NULL); |
a52d9a80 CM |
176 | if (!ret) |
177 | return prev; | |
178 | return ret; | |
179 | } | |
180 | ||
d352ac68 | 181 | /* check to see if two extent_map structs are adjacent and safe to merge */ |
d1310b2e | 182 | static int mergable_maps(struct extent_map *prev, struct extent_map *next) |
a52d9a80 | 183 | { |
7f3c74fb CM |
184 | if (test_bit(EXTENT_FLAG_PINNED, &prev->flags)) |
185 | return 0; | |
186 | ||
c8b97818 CM |
187 | /* |
188 | * don't merge compressed extents, we need to know their | |
189 | * actual size | |
190 | */ | |
191 | if (test_bit(EXTENT_FLAG_COMPRESSED, &prev->flags)) | |
192 | return 0; | |
193 | ||
d1310b2e CM |
194 | if (extent_map_end(prev) == next->start && |
195 | prev->flags == next->flags && | |
196 | prev->bdev == next->bdev && | |
197 | ((next->block_start == EXTENT_MAP_HOLE && | |
198 | prev->block_start == EXTENT_MAP_HOLE) || | |
199 | (next->block_start == EXTENT_MAP_INLINE && | |
200 | prev->block_start == EXTENT_MAP_INLINE) || | |
201 | (next->block_start == EXTENT_MAP_DELALLOC && | |
202 | prev->block_start == EXTENT_MAP_DELALLOC) || | |
203 | (next->block_start < EXTENT_MAP_LAST_BYTE - 1 && | |
204 | next->block_start == extent_map_block_end(prev)))) { | |
205 | return 1; | |
206 | } | |
a52d9a80 CM |
207 | return 0; |
208 | } | |
209 | ||
9d2423c5 CH |
210 | /** |
211 | * add_extent_mapping - add new extent map to the extent tree | |
212 | * @tree: tree to insert new map in | |
213 | * @em: map to insert | |
214 | * | |
215 | * Insert @em into @tree or perform a simple forward/backward merge with | |
216 | * existing mappings. The extent_map struct passed in will be inserted | |
217 | * into the tree directly, with an additional reference taken, or a | |
218 | * reference dropped if the merge attempt was sucessfull. | |
a52d9a80 CM |
219 | */ |
220 | int add_extent_mapping(struct extent_map_tree *tree, | |
221 | struct extent_map *em) | |
222 | { | |
223 | int ret = 0; | |
d1310b2e | 224 | struct extent_map *merge = NULL; |
a52d9a80 | 225 | struct rb_node *rb; |
7c2fe32a | 226 | struct extent_map *exist; |
a52d9a80 | 227 | |
7c2fe32a CM |
228 | exist = lookup_extent_mapping(tree, em->start, em->len); |
229 | if (exist) { | |
230 | free_extent_map(exist); | |
231 | ret = -EEXIST; | |
232 | goto out; | |
233 | } | |
64f26f74 | 234 | assert_spin_locked(&tree->lock); |
d1310b2e | 235 | rb = tree_insert(&tree->map, em->start, &em->rb_node); |
a52d9a80 | 236 | if (rb) { |
a52d9a80 | 237 | ret = -EEXIST; |
e6dcd2dc | 238 | free_extent_map(merge); |
a52d9a80 CM |
239 | goto out; |
240 | } | |
241 | atomic_inc(&em->refs); | |
242 | if (em->start != 0) { | |
243 | rb = rb_prev(&em->rb_node); | |
244 | if (rb) | |
d1310b2e CM |
245 | merge = rb_entry(rb, struct extent_map, rb_node); |
246 | if (rb && mergable_maps(merge, em)) { | |
247 | em->start = merge->start; | |
248 | em->len += merge->len; | |
c8b97818 | 249 | em->block_len += merge->block_len; |
d1310b2e CM |
250 | em->block_start = merge->block_start; |
251 | merge->in_tree = 0; | |
252 | rb_erase(&merge->rb_node, &tree->map); | |
253 | free_extent_map(merge); | |
a52d9a80 CM |
254 | } |
255 | } | |
d1310b2e CM |
256 | rb = rb_next(&em->rb_node); |
257 | if (rb) | |
258 | merge = rb_entry(rb, struct extent_map, rb_node); | |
259 | if (rb && mergable_maps(em, merge)) { | |
260 | em->len += merge->len; | |
c8b97818 | 261 | em->block_len += merge->len; |
d1310b2e CM |
262 | rb_erase(&merge->rb_node, &tree->map); |
263 | merge->in_tree = 0; | |
264 | free_extent_map(merge); | |
265 | } | |
a52d9a80 | 266 | out: |
a52d9a80 CM |
267 | return ret; |
268 | } | |
269 | EXPORT_SYMBOL(add_extent_mapping); | |
270 | ||
d352ac68 | 271 | /* simple helper to do math around the end of an extent, handling wrap */ |
d1310b2e CM |
272 | static u64 range_end(u64 start, u64 len) |
273 | { | |
274 | if (start + len < start) | |
275 | return (u64)-1; | |
276 | return start + len; | |
277 | } | |
278 | ||
9d2423c5 CH |
279 | /** |
280 | * lookup_extent_mapping - lookup extent_map | |
281 | * @tree: tree to lookup in | |
282 | * @start: byte offset to start the search | |
283 | * @len: length of the lookup range | |
284 | * | |
285 | * Find and return the first extent_map struct in @tree that intersects the | |
286 | * [start, len] range. There may be additional objects in the tree that | |
287 | * intersect, so check the object returned carefully to make sure that no | |
288 | * additional lookups are needed. | |
a52d9a80 CM |
289 | */ |
290 | struct extent_map *lookup_extent_mapping(struct extent_map_tree *tree, | |
d1310b2e | 291 | u64 start, u64 len) |
a52d9a80 CM |
292 | { |
293 | struct extent_map *em; | |
294 | struct rb_node *rb_node; | |
306929f3 CH |
295 | struct rb_node *prev = NULL; |
296 | struct rb_node *next = NULL; | |
297 | u64 end = range_end(start, len); | |
298 | ||
64f26f74 | 299 | assert_spin_locked(&tree->lock); |
5f56406a CM |
300 | rb_node = __tree_search(&tree->map, start, &prev, &next); |
301 | if (!rb_node && prev) { | |
302 | em = rb_entry(prev, struct extent_map, rb_node); | |
d1310b2e | 303 | if (end > em->start && start < extent_map_end(em)) |
5f56406a CM |
304 | goto found; |
305 | } | |
306 | if (!rb_node && next) { | |
307 | em = rb_entry(next, struct extent_map, rb_node); | |
d1310b2e | 308 | if (end > em->start && start < extent_map_end(em)) |
5f56406a CM |
309 | goto found; |
310 | } | |
a52d9a80 CM |
311 | if (!rb_node) { |
312 | em = NULL; | |
313 | goto out; | |
314 | } | |
315 | if (IS_ERR(rb_node)) { | |
316 | em = ERR_PTR(PTR_ERR(rb_node)); | |
317 | goto out; | |
318 | } | |
319 | em = rb_entry(rb_node, struct extent_map, rb_node); | |
d1310b2e CM |
320 | if (end > em->start && start < extent_map_end(em)) |
321 | goto found; | |
322 | ||
323 | em = NULL; | |
324 | goto out; | |
325 | ||
5f56406a | 326 | found: |
a52d9a80 CM |
327 | atomic_inc(&em->refs); |
328 | out: | |
a52d9a80 CM |
329 | return em; |
330 | } | |
331 | EXPORT_SYMBOL(lookup_extent_mapping); | |
332 | ||
9d2423c5 CH |
333 | /** |
334 | * remove_extent_mapping - removes an extent_map from the extent tree | |
335 | * @tree: extent tree to remove from | |
336 | * @em: extent map beeing removed | |
337 | * | |
338 | * Removes @em from @tree. No reference counts are dropped, and no checks | |
339 | * are done to see if the range is in use | |
a52d9a80 CM |
340 | */ |
341 | int remove_extent_mapping(struct extent_map_tree *tree, struct extent_map *em) | |
342 | { | |
d1310b2e | 343 | int ret = 0; |
a52d9a80 | 344 | |
7f3c74fb | 345 | WARN_ON(test_bit(EXTENT_FLAG_PINNED, &em->flags)); |
64f26f74 | 346 | assert_spin_locked(&tree->lock); |
d1310b2e CM |
347 | rb_erase(&em->rb_node, &tree->map); |
348 | em->in_tree = 0; | |
a52d9a80 CM |
349 | return ret; |
350 | } | |
351 | EXPORT_SYMBOL(remove_extent_mapping); |