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Commit | Line | Data |
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d1310b2e | 1 | #include <linux/err.h> |
d1310b2e | 2 | #include <linux/slab.h> |
a52d9a80 CM |
3 | #include <linux/module.h> |
4 | #include <linux/spinlock.h> | |
d1310b2e | 5 | #include <linux/hardirq.h> |
a52d9a80 CM |
6 | #include "extent_map.h" |
7 | ||
86479a04 | 8 | |
a52d9a80 | 9 | static struct kmem_cache *extent_map_cache; |
ca664626 | 10 | |
2f4cbe64 | 11 | int __init extent_map_init(void) |
a52d9a80 | 12 | { |
9601e3f6 CH |
13 | extent_map_cache = kmem_cache_create("extent_map", |
14 | sizeof(struct extent_map), 0, | |
15 | SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD, NULL); | |
2f4cbe64 WB |
16 | if (!extent_map_cache) |
17 | return -ENOMEM; | |
2f4cbe64 | 18 | return 0; |
a52d9a80 CM |
19 | } |
20 | ||
17636e03 | 21 | void extent_map_exit(void) |
a52d9a80 | 22 | { |
a52d9a80 CM |
23 | if (extent_map_cache) |
24 | kmem_cache_destroy(extent_map_cache); | |
a52d9a80 CM |
25 | } |
26 | ||
9d2423c5 CH |
27 | /** |
28 | * extent_map_tree_init - initialize extent map tree | |
29 | * @tree: tree to initialize | |
30 | * @mask: flags for memory allocations during tree operations | |
31 | * | |
32 | * Initialize the extent tree @tree. Should be called for each new inode | |
33 | * or other user of the extent_map interface. | |
34 | */ | |
d1310b2e | 35 | void extent_map_tree_init(struct extent_map_tree *tree, gfp_t mask) |
a52d9a80 | 36 | { |
6bef4d31 | 37 | tree->map = RB_ROOT; |
890871be | 38 | rwlock_init(&tree->lock); |
a52d9a80 | 39 | } |
a52d9a80 | 40 | |
9d2423c5 CH |
41 | /** |
42 | * alloc_extent_map - allocate new extent map structure | |
43 | * @mask: memory allocation flags | |
44 | * | |
45 | * Allocate a new extent_map structure. The new structure is | |
46 | * returned with a reference count of one and needs to be | |
47 | * freed using free_extent_map() | |
48 | */ | |
a52d9a80 CM |
49 | struct extent_map *alloc_extent_map(gfp_t mask) |
50 | { | |
51 | struct extent_map *em; | |
52 | em = kmem_cache_alloc(extent_map_cache, mask); | |
53 | if (!em || IS_ERR(em)) | |
54 | return em; | |
55 | em->in_tree = 0; | |
d1310b2e | 56 | em->flags = 0; |
a52d9a80 CM |
57 | atomic_set(&em->refs, 1); |
58 | return em; | |
59 | } | |
a52d9a80 | 60 | |
9d2423c5 CH |
61 | /** |
62 | * free_extent_map - drop reference count of an extent_map | |
63 | * @em: extent map beeing releasead | |
64 | * | |
65 | * Drops the reference out on @em by one and free the structure | |
66 | * if the reference count hits zero. | |
67 | */ | |
a52d9a80 CM |
68 | void free_extent_map(struct extent_map *em) |
69 | { | |
2bf5a725 CM |
70 | if (!em) |
71 | return; | |
d1310b2e | 72 | WARN_ON(atomic_read(&em->refs) == 0); |
a52d9a80 CM |
73 | if (atomic_dec_and_test(&em->refs)) { |
74 | WARN_ON(em->in_tree); | |
75 | kmem_cache_free(extent_map_cache, em); | |
76 | } | |
77 | } | |
a52d9a80 | 78 | |
a52d9a80 CM |
79 | static struct rb_node *tree_insert(struct rb_root *root, u64 offset, |
80 | struct rb_node *node) | |
81 | { | |
d397712b CM |
82 | struct rb_node **p = &root->rb_node; |
83 | struct rb_node *parent = NULL; | |
d1310b2e | 84 | struct extent_map *entry; |
a52d9a80 | 85 | |
d397712b | 86 | while (*p) { |
a52d9a80 | 87 | parent = *p; |
d1310b2e CM |
88 | entry = rb_entry(parent, struct extent_map, rb_node); |
89 | ||
90 | WARN_ON(!entry->in_tree); | |
a52d9a80 CM |
91 | |
92 | if (offset < entry->start) | |
93 | p = &(*p)->rb_left; | |
d1310b2e | 94 | else if (offset >= extent_map_end(entry)) |
a52d9a80 CM |
95 | p = &(*p)->rb_right; |
96 | else | |
97 | return parent; | |
98 | } | |
99 | ||
d1310b2e | 100 | entry = rb_entry(node, struct extent_map, rb_node); |
a52d9a80 CM |
101 | entry->in_tree = 1; |
102 | rb_link_node(node, parent, p); | |
103 | rb_insert_color(node, root); | |
104 | return NULL; | |
105 | } | |
106 | ||
d352ac68 CM |
107 | /* |
108 | * search through the tree for an extent_map with a given offset. If | |
109 | * it can't be found, try to find some neighboring extents | |
110 | */ | |
a52d9a80 | 111 | static struct rb_node *__tree_search(struct rb_root *root, u64 offset, |
5f56406a CM |
112 | struct rb_node **prev_ret, |
113 | struct rb_node **next_ret) | |
a52d9a80 | 114 | { |
d397712b | 115 | struct rb_node *n = root->rb_node; |
a52d9a80 | 116 | struct rb_node *prev = NULL; |
5f56406a | 117 | struct rb_node *orig_prev = NULL; |
d1310b2e CM |
118 | struct extent_map *entry; |
119 | struct extent_map *prev_entry = NULL; | |
a52d9a80 | 120 | |
d397712b | 121 | while (n) { |
d1310b2e | 122 | entry = rb_entry(n, struct extent_map, rb_node); |
a52d9a80 CM |
123 | prev = n; |
124 | prev_entry = entry; | |
125 | ||
d1310b2e CM |
126 | WARN_ON(!entry->in_tree); |
127 | ||
a52d9a80 CM |
128 | if (offset < entry->start) |
129 | n = n->rb_left; | |
d1310b2e | 130 | else if (offset >= extent_map_end(entry)) |
a52d9a80 CM |
131 | n = n->rb_right; |
132 | else | |
133 | return n; | |
134 | } | |
5f56406a CM |
135 | |
136 | if (prev_ret) { | |
137 | orig_prev = prev; | |
d397712b | 138 | while (prev && offset >= extent_map_end(prev_entry)) { |
5f56406a | 139 | prev = rb_next(prev); |
d1310b2e | 140 | prev_entry = rb_entry(prev, struct extent_map, rb_node); |
5f56406a CM |
141 | } |
142 | *prev_ret = prev; | |
143 | prev = orig_prev; | |
144 | } | |
145 | ||
146 | if (next_ret) { | |
d1310b2e | 147 | prev_entry = rb_entry(prev, struct extent_map, rb_node); |
d397712b | 148 | while (prev && offset < prev_entry->start) { |
5f56406a | 149 | prev = rb_prev(prev); |
d1310b2e | 150 | prev_entry = rb_entry(prev, struct extent_map, rb_node); |
5f56406a CM |
151 | } |
152 | *next_ret = prev; | |
a52d9a80 | 153 | } |
a52d9a80 CM |
154 | return NULL; |
155 | } | |
156 | ||
d352ac68 | 157 | /* check to see if two extent_map structs are adjacent and safe to merge */ |
d1310b2e | 158 | static int mergable_maps(struct extent_map *prev, struct extent_map *next) |
a52d9a80 | 159 | { |
7f3c74fb CM |
160 | if (test_bit(EXTENT_FLAG_PINNED, &prev->flags)) |
161 | return 0; | |
162 | ||
c8b97818 CM |
163 | /* |
164 | * don't merge compressed extents, we need to know their | |
165 | * actual size | |
166 | */ | |
167 | if (test_bit(EXTENT_FLAG_COMPRESSED, &prev->flags)) | |
168 | return 0; | |
169 | ||
d1310b2e CM |
170 | if (extent_map_end(prev) == next->start && |
171 | prev->flags == next->flags && | |
172 | prev->bdev == next->bdev && | |
173 | ((next->block_start == EXTENT_MAP_HOLE && | |
174 | prev->block_start == EXTENT_MAP_HOLE) || | |
175 | (next->block_start == EXTENT_MAP_INLINE && | |
176 | prev->block_start == EXTENT_MAP_INLINE) || | |
177 | (next->block_start == EXTENT_MAP_DELALLOC && | |
178 | prev->block_start == EXTENT_MAP_DELALLOC) || | |
179 | (next->block_start < EXTENT_MAP_LAST_BYTE - 1 && | |
180 | next->block_start == extent_map_block_end(prev)))) { | |
181 | return 1; | |
182 | } | |
a52d9a80 CM |
183 | return 0; |
184 | } | |
185 | ||
a1ed835e CM |
186 | int unpin_extent_cache(struct extent_map_tree *tree, u64 start, u64 len) |
187 | { | |
188 | int ret = 0; | |
189 | struct extent_map *merge = NULL; | |
190 | struct rb_node *rb; | |
191 | struct extent_map *em; | |
192 | ||
193 | write_lock(&tree->lock); | |
194 | em = lookup_extent_mapping(tree, start, len); | |
195 | ||
4eb3991c | 196 | WARN_ON(!em || em->start != start); |
a1ed835e CM |
197 | |
198 | if (!em) | |
199 | goto out; | |
200 | ||
201 | clear_bit(EXTENT_FLAG_PINNED, &em->flags); | |
202 | ||
203 | if (em->start != 0) { | |
204 | rb = rb_prev(&em->rb_node); | |
205 | if (rb) | |
206 | merge = rb_entry(rb, struct extent_map, rb_node); | |
207 | if (rb && mergable_maps(merge, em)) { | |
208 | em->start = merge->start; | |
209 | em->len += merge->len; | |
210 | em->block_len += merge->block_len; | |
211 | em->block_start = merge->block_start; | |
212 | merge->in_tree = 0; | |
213 | rb_erase(&merge->rb_node, &tree->map); | |
214 | free_extent_map(merge); | |
215 | } | |
216 | } | |
217 | ||
218 | rb = rb_next(&em->rb_node); | |
219 | if (rb) | |
220 | merge = rb_entry(rb, struct extent_map, rb_node); | |
221 | if (rb && mergable_maps(em, merge)) { | |
222 | em->len += merge->len; | |
223 | em->block_len += merge->len; | |
224 | rb_erase(&merge->rb_node, &tree->map); | |
225 | merge->in_tree = 0; | |
226 | free_extent_map(merge); | |
227 | } | |
228 | ||
229 | free_extent_map(em); | |
230 | out: | |
231 | write_unlock(&tree->lock); | |
232 | return ret; | |
233 | ||
234 | } | |
235 | ||
9d2423c5 CH |
236 | /** |
237 | * add_extent_mapping - add new extent map to the extent tree | |
238 | * @tree: tree to insert new map in | |
239 | * @em: map to insert | |
240 | * | |
241 | * Insert @em into @tree or perform a simple forward/backward merge with | |
242 | * existing mappings. The extent_map struct passed in will be inserted | |
243 | * into the tree directly, with an additional reference taken, or a | |
af901ca1 | 244 | * reference dropped if the merge attempt was successfull. |
a52d9a80 CM |
245 | */ |
246 | int add_extent_mapping(struct extent_map_tree *tree, | |
247 | struct extent_map *em) | |
248 | { | |
249 | int ret = 0; | |
d1310b2e | 250 | struct extent_map *merge = NULL; |
a52d9a80 | 251 | struct rb_node *rb; |
7c2fe32a | 252 | struct extent_map *exist; |
a52d9a80 | 253 | |
7c2fe32a CM |
254 | exist = lookup_extent_mapping(tree, em->start, em->len); |
255 | if (exist) { | |
256 | free_extent_map(exist); | |
257 | ret = -EEXIST; | |
258 | goto out; | |
259 | } | |
d1310b2e | 260 | rb = tree_insert(&tree->map, em->start, &em->rb_node); |
a52d9a80 | 261 | if (rb) { |
a52d9a80 CM |
262 | ret = -EEXIST; |
263 | goto out; | |
264 | } | |
265 | atomic_inc(&em->refs); | |
266 | if (em->start != 0) { | |
267 | rb = rb_prev(&em->rb_node); | |
268 | if (rb) | |
d1310b2e CM |
269 | merge = rb_entry(rb, struct extent_map, rb_node); |
270 | if (rb && mergable_maps(merge, em)) { | |
271 | em->start = merge->start; | |
272 | em->len += merge->len; | |
c8b97818 | 273 | em->block_len += merge->block_len; |
d1310b2e CM |
274 | em->block_start = merge->block_start; |
275 | merge->in_tree = 0; | |
276 | rb_erase(&merge->rb_node, &tree->map); | |
277 | free_extent_map(merge); | |
a52d9a80 CM |
278 | } |
279 | } | |
d1310b2e CM |
280 | rb = rb_next(&em->rb_node); |
281 | if (rb) | |
282 | merge = rb_entry(rb, struct extent_map, rb_node); | |
283 | if (rb && mergable_maps(em, merge)) { | |
284 | em->len += merge->len; | |
c8b97818 | 285 | em->block_len += merge->len; |
d1310b2e CM |
286 | rb_erase(&merge->rb_node, &tree->map); |
287 | merge->in_tree = 0; | |
288 | free_extent_map(merge); | |
289 | } | |
a52d9a80 | 290 | out: |
a52d9a80 CM |
291 | return ret; |
292 | } | |
a52d9a80 | 293 | |
d352ac68 | 294 | /* simple helper to do math around the end of an extent, handling wrap */ |
d1310b2e CM |
295 | static u64 range_end(u64 start, u64 len) |
296 | { | |
297 | if (start + len < start) | |
298 | return (u64)-1; | |
299 | return start + len; | |
300 | } | |
301 | ||
9d2423c5 CH |
302 | /** |
303 | * lookup_extent_mapping - lookup extent_map | |
304 | * @tree: tree to lookup in | |
305 | * @start: byte offset to start the search | |
306 | * @len: length of the lookup range | |
307 | * | |
308 | * Find and return the first extent_map struct in @tree that intersects the | |
309 | * [start, len] range. There may be additional objects in the tree that | |
310 | * intersect, so check the object returned carefully to make sure that no | |
311 | * additional lookups are needed. | |
a52d9a80 CM |
312 | */ |
313 | struct extent_map *lookup_extent_mapping(struct extent_map_tree *tree, | |
d1310b2e | 314 | u64 start, u64 len) |
a52d9a80 CM |
315 | { |
316 | struct extent_map *em; | |
317 | struct rb_node *rb_node; | |
306929f3 CH |
318 | struct rb_node *prev = NULL; |
319 | struct rb_node *next = NULL; | |
320 | u64 end = range_end(start, len); | |
321 | ||
5f56406a CM |
322 | rb_node = __tree_search(&tree->map, start, &prev, &next); |
323 | if (!rb_node && prev) { | |
324 | em = rb_entry(prev, struct extent_map, rb_node); | |
d1310b2e | 325 | if (end > em->start && start < extent_map_end(em)) |
5f56406a CM |
326 | goto found; |
327 | } | |
328 | if (!rb_node && next) { | |
329 | em = rb_entry(next, struct extent_map, rb_node); | |
d1310b2e | 330 | if (end > em->start && start < extent_map_end(em)) |
5f56406a CM |
331 | goto found; |
332 | } | |
a52d9a80 CM |
333 | if (!rb_node) { |
334 | em = NULL; | |
335 | goto out; | |
336 | } | |
337 | if (IS_ERR(rb_node)) { | |
d0b678cb | 338 | em = ERR_CAST(rb_node); |
a52d9a80 CM |
339 | goto out; |
340 | } | |
341 | em = rb_entry(rb_node, struct extent_map, rb_node); | |
d1310b2e CM |
342 | if (end > em->start && start < extent_map_end(em)) |
343 | goto found; | |
344 | ||
345 | em = NULL; | |
346 | goto out; | |
347 | ||
5f56406a | 348 | found: |
a52d9a80 CM |
349 | atomic_inc(&em->refs); |
350 | out: | |
a52d9a80 CM |
351 | return em; |
352 | } | |
a52d9a80 | 353 | |
b917b7c3 CM |
354 | /** |
355 | * search_extent_mapping - find a nearby extent map | |
356 | * @tree: tree to lookup in | |
357 | * @start: byte offset to start the search | |
358 | * @len: length of the lookup range | |
359 | * | |
360 | * Find and return the first extent_map struct in @tree that intersects the | |
361 | * [start, len] range. | |
362 | * | |
363 | * If one can't be found, any nearby extent may be returned | |
364 | */ | |
365 | struct extent_map *search_extent_mapping(struct extent_map_tree *tree, | |
366 | u64 start, u64 len) | |
367 | { | |
368 | struct extent_map *em; | |
369 | struct rb_node *rb_node; | |
370 | struct rb_node *prev = NULL; | |
371 | struct rb_node *next = NULL; | |
372 | ||
373 | rb_node = __tree_search(&tree->map, start, &prev, &next); | |
374 | if (!rb_node && prev) { | |
375 | em = rb_entry(prev, struct extent_map, rb_node); | |
376 | goto found; | |
377 | } | |
378 | if (!rb_node && next) { | |
379 | em = rb_entry(next, struct extent_map, rb_node); | |
380 | goto found; | |
381 | } | |
382 | if (!rb_node) { | |
383 | em = NULL; | |
384 | goto out; | |
385 | } | |
386 | if (IS_ERR(rb_node)) { | |
d0b678cb | 387 | em = ERR_CAST(rb_node); |
b917b7c3 CM |
388 | goto out; |
389 | } | |
390 | em = rb_entry(rb_node, struct extent_map, rb_node); | |
391 | goto found; | |
392 | ||
393 | em = NULL; | |
394 | goto out; | |
395 | ||
396 | found: | |
397 | atomic_inc(&em->refs); | |
398 | out: | |
399 | return em; | |
400 | } | |
401 | ||
9d2423c5 CH |
402 | /** |
403 | * remove_extent_mapping - removes an extent_map from the extent tree | |
404 | * @tree: extent tree to remove from | |
405 | * @em: extent map beeing removed | |
406 | * | |
407 | * Removes @em from @tree. No reference counts are dropped, and no checks | |
408 | * are done to see if the range is in use | |
a52d9a80 CM |
409 | */ |
410 | int remove_extent_mapping(struct extent_map_tree *tree, struct extent_map *em) | |
411 | { | |
d1310b2e | 412 | int ret = 0; |
a52d9a80 | 413 | |
7f3c74fb | 414 | WARN_ON(test_bit(EXTENT_FLAG_PINNED, &em->flags)); |
d1310b2e CM |
415 | rb_erase(&em->rb_node, &tree->map); |
416 | em->in_tree = 0; | |
a52d9a80 CM |
417 | return ret; |
418 | } |