Commit | Line | Data |
---|---|---|
d1310b2e | 1 | #include <linux/err.h> |
d1310b2e | 2 | #include <linux/slab.h> |
a52d9a80 | 3 | #include <linux/spinlock.h> |
d1310b2e | 4 | #include <linux/hardirq.h> |
261507a0 | 5 | #include "ctree.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 | { |
837e1972 | 13 | extent_map_cache = kmem_cache_create("btrfs_extent_map", |
9601e3f6 CH |
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 | |
9d2423c5 CH |
30 | * |
31 | * Initialize the extent tree @tree. Should be called for each new inode | |
32 | * or other user of the extent_map interface. | |
33 | */ | |
a8067e02 | 34 | void extent_map_tree_init(struct extent_map_tree *tree) |
a52d9a80 | 35 | { |
6bef4d31 | 36 | tree->map = RB_ROOT; |
5dc562c5 | 37 | INIT_LIST_HEAD(&tree->modified_extents); |
890871be | 38 | rwlock_init(&tree->lock); |
a52d9a80 | 39 | } |
a52d9a80 | 40 | |
9d2423c5 CH |
41 | /** |
42 | * alloc_extent_map - allocate new extent map structure | |
9d2423c5 CH |
43 | * |
44 | * Allocate a new extent_map structure. The new structure is | |
45 | * returned with a reference count of one and needs to be | |
46 | * freed using free_extent_map() | |
47 | */ | |
172ddd60 | 48 | struct extent_map *alloc_extent_map(void) |
a52d9a80 CM |
49 | { |
50 | struct extent_map *em; | |
70c8a91c | 51 | em = kmem_cache_zalloc(extent_map_cache, GFP_NOFS); |
c26a9203 TI |
52 | if (!em) |
53 | return NULL; | |
a52d9a80 | 54 | em->in_tree = 0; |
d1310b2e | 55 | em->flags = 0; |
261507a0 | 56 | em->compress_type = BTRFS_COMPRESS_NONE; |
5dc562c5 | 57 | em->generation = 0; |
a52d9a80 | 58 | atomic_set(&em->refs, 1); |
5dc562c5 | 59 | INIT_LIST_HEAD(&em->list); |
a52d9a80 CM |
60 | return em; |
61 | } | |
a52d9a80 | 62 | |
9d2423c5 CH |
63 | /** |
64 | * free_extent_map - drop reference count of an extent_map | |
65 | * @em: extent map beeing releasead | |
66 | * | |
67 | * Drops the reference out on @em by one and free the structure | |
68 | * if the reference count hits zero. | |
69 | */ | |
a52d9a80 CM |
70 | void free_extent_map(struct extent_map *em) |
71 | { | |
2bf5a725 CM |
72 | if (!em) |
73 | return; | |
d1310b2e | 74 | WARN_ON(atomic_read(&em->refs) == 0); |
a52d9a80 CM |
75 | if (atomic_dec_and_test(&em->refs)) { |
76 | WARN_ON(em->in_tree); | |
5dc562c5 | 77 | WARN_ON(!list_empty(&em->list)); |
a52d9a80 CM |
78 | kmem_cache_free(extent_map_cache, em); |
79 | } | |
80 | } | |
a52d9a80 | 81 | |
a52d9a80 CM |
82 | static struct rb_node *tree_insert(struct rb_root *root, u64 offset, |
83 | struct rb_node *node) | |
84 | { | |
d397712b CM |
85 | struct rb_node **p = &root->rb_node; |
86 | struct rb_node *parent = NULL; | |
d1310b2e | 87 | struct extent_map *entry; |
a52d9a80 | 88 | |
d397712b | 89 | while (*p) { |
a52d9a80 | 90 | parent = *p; |
d1310b2e CM |
91 | entry = rb_entry(parent, struct extent_map, rb_node); |
92 | ||
93 | WARN_ON(!entry->in_tree); | |
a52d9a80 CM |
94 | |
95 | if (offset < entry->start) | |
96 | p = &(*p)->rb_left; | |
d1310b2e | 97 | else if (offset >= extent_map_end(entry)) |
a52d9a80 CM |
98 | p = &(*p)->rb_right; |
99 | else | |
100 | return parent; | |
101 | } | |
102 | ||
d1310b2e | 103 | entry = rb_entry(node, struct extent_map, rb_node); |
a52d9a80 CM |
104 | entry->in_tree = 1; |
105 | rb_link_node(node, parent, p); | |
106 | rb_insert_color(node, root); | |
107 | return NULL; | |
108 | } | |
109 | ||
d352ac68 CM |
110 | /* |
111 | * search through the tree for an extent_map with a given offset. If | |
112 | * it can't be found, try to find some neighboring extents | |
113 | */ | |
a52d9a80 | 114 | static struct rb_node *__tree_search(struct rb_root *root, u64 offset, |
5f56406a CM |
115 | struct rb_node **prev_ret, |
116 | struct rb_node **next_ret) | |
a52d9a80 | 117 | { |
d397712b | 118 | struct rb_node *n = root->rb_node; |
a52d9a80 | 119 | struct rb_node *prev = NULL; |
5f56406a | 120 | struct rb_node *orig_prev = NULL; |
d1310b2e CM |
121 | struct extent_map *entry; |
122 | struct extent_map *prev_entry = NULL; | |
a52d9a80 | 123 | |
d397712b | 124 | while (n) { |
d1310b2e | 125 | entry = rb_entry(n, struct extent_map, rb_node); |
a52d9a80 CM |
126 | prev = n; |
127 | prev_entry = entry; | |
128 | ||
d1310b2e CM |
129 | WARN_ON(!entry->in_tree); |
130 | ||
a52d9a80 CM |
131 | if (offset < entry->start) |
132 | n = n->rb_left; | |
d1310b2e | 133 | else if (offset >= extent_map_end(entry)) |
a52d9a80 CM |
134 | n = n->rb_right; |
135 | else | |
136 | return n; | |
137 | } | |
5f56406a CM |
138 | |
139 | if (prev_ret) { | |
140 | orig_prev = prev; | |
d397712b | 141 | while (prev && offset >= extent_map_end(prev_entry)) { |
5f56406a | 142 | prev = rb_next(prev); |
d1310b2e | 143 | prev_entry = rb_entry(prev, struct extent_map, rb_node); |
5f56406a CM |
144 | } |
145 | *prev_ret = prev; | |
146 | prev = orig_prev; | |
147 | } | |
148 | ||
149 | if (next_ret) { | |
d1310b2e | 150 | prev_entry = rb_entry(prev, struct extent_map, rb_node); |
d397712b | 151 | while (prev && offset < prev_entry->start) { |
5f56406a | 152 | prev = rb_prev(prev); |
d1310b2e | 153 | prev_entry = rb_entry(prev, struct extent_map, rb_node); |
5f56406a CM |
154 | } |
155 | *next_ret = prev; | |
a52d9a80 | 156 | } |
a52d9a80 CM |
157 | return NULL; |
158 | } | |
159 | ||
d352ac68 | 160 | /* check to see if two extent_map structs are adjacent and safe to merge */ |
d1310b2e | 161 | static int mergable_maps(struct extent_map *prev, struct extent_map *next) |
a52d9a80 | 162 | { |
7f3c74fb CM |
163 | if (test_bit(EXTENT_FLAG_PINNED, &prev->flags)) |
164 | return 0; | |
165 | ||
c8b97818 CM |
166 | /* |
167 | * don't merge compressed extents, we need to know their | |
168 | * actual size | |
169 | */ | |
170 | if (test_bit(EXTENT_FLAG_COMPRESSED, &prev->flags)) | |
171 | return 0; | |
172 | ||
201a9038 JB |
173 | if (test_bit(EXTENT_FLAG_LOGGING, &prev->flags) || |
174 | test_bit(EXTENT_FLAG_LOGGING, &next->flags)) | |
175 | return 0; | |
176 | ||
09a2a8f9 JB |
177 | /* |
178 | * We don't want to merge stuff that hasn't been written to the log yet | |
179 | * since it may not reflect exactly what is on disk, and that would be | |
180 | * bad. | |
181 | */ | |
182 | if (!list_empty(&prev->list) || !list_empty(&next->list)) | |
183 | return 0; | |
184 | ||
d1310b2e CM |
185 | if (extent_map_end(prev) == next->start && |
186 | prev->flags == next->flags && | |
187 | prev->bdev == next->bdev && | |
188 | ((next->block_start == EXTENT_MAP_HOLE && | |
189 | prev->block_start == EXTENT_MAP_HOLE) || | |
190 | (next->block_start == EXTENT_MAP_INLINE && | |
191 | prev->block_start == EXTENT_MAP_INLINE) || | |
192 | (next->block_start == EXTENT_MAP_DELALLOC && | |
193 | prev->block_start == EXTENT_MAP_DELALLOC) || | |
194 | (next->block_start < EXTENT_MAP_LAST_BYTE - 1 && | |
195 | next->block_start == extent_map_block_end(prev)))) { | |
196 | return 1; | |
197 | } | |
a52d9a80 CM |
198 | return 0; |
199 | } | |
200 | ||
4d2c8f62 | 201 | static void try_merge_map(struct extent_map_tree *tree, struct extent_map *em) |
a1ed835e | 202 | { |
a1ed835e CM |
203 | struct extent_map *merge = NULL; |
204 | struct rb_node *rb; | |
a1ed835e CM |
205 | |
206 | if (em->start != 0) { | |
207 | rb = rb_prev(&em->rb_node); | |
208 | if (rb) | |
209 | merge = rb_entry(rb, struct extent_map, rb_node); | |
210 | if (rb && mergable_maps(merge, em)) { | |
211 | em->start = merge->start; | |
70c8a91c | 212 | em->orig_start = merge->orig_start; |
a1ed835e CM |
213 | em->len += merge->len; |
214 | em->block_len += merge->block_len; | |
215 | em->block_start = merge->block_start; | |
216 | merge->in_tree = 0; | |
70c8a91c JB |
217 | em->mod_len = (em->mod_len + em->mod_start) - merge->mod_start; |
218 | em->mod_start = merge->mod_start; | |
219 | em->generation = max(em->generation, merge->generation); | |
5dc562c5 | 220 | |
a1ed835e CM |
221 | rb_erase(&merge->rb_node, &tree->map); |
222 | free_extent_map(merge); | |
223 | } | |
224 | } | |
225 | ||
226 | rb = rb_next(&em->rb_node); | |
227 | if (rb) | |
228 | merge = rb_entry(rb, struct extent_map, rb_node); | |
229 | if (rb && mergable_maps(em, merge)) { | |
230 | em->len += merge->len; | |
231 | em->block_len += merge->len; | |
232 | rb_erase(&merge->rb_node, &tree->map); | |
233 | merge->in_tree = 0; | |
70c8a91c JB |
234 | em->mod_len = (merge->mod_start + merge->mod_len) - em->mod_start; |
235 | em->generation = max(em->generation, merge->generation); | |
a1ed835e CM |
236 | free_extent_map(merge); |
237 | } | |
4d2c8f62 LZ |
238 | } |
239 | ||
5dc562c5 | 240 | /** |
52b1de91 | 241 | * unpin_extent_cache - unpin an extent from the cache |
5dc562c5 JB |
242 | * @tree: tree to unpin the extent in |
243 | * @start: logical offset in the file | |
244 | * @len: length of the extent | |
245 | * @gen: generation that this extent has been modified in | |
5dc562c5 JB |
246 | * |
247 | * Called after an extent has been written to disk properly. Set the generation | |
248 | * to the generation that actually added the file item to the inode so we know | |
249 | * we need to sync this extent when we call fsync(). | |
250 | */ | |
251 | int unpin_extent_cache(struct extent_map_tree *tree, u64 start, u64 len, | |
252 | u64 gen) | |
4d2c8f62 LZ |
253 | { |
254 | int ret = 0; | |
255 | struct extent_map *em; | |
4e2f84e6 | 256 | bool prealloc = false; |
4d2c8f62 LZ |
257 | |
258 | write_lock(&tree->lock); | |
259 | em = lookup_extent_mapping(tree, start, len); | |
260 | ||
261 | WARN_ON(!em || em->start != start); | |
262 | ||
263 | if (!em) | |
264 | goto out; | |
265 | ||
201a9038 JB |
266 | if (!test_bit(EXTENT_FLAG_LOGGING, &em->flags)) |
267 | list_move(&em->list, &tree->modified_extents); | |
5dc562c5 | 268 | em->generation = gen; |
4d2c8f62 | 269 | clear_bit(EXTENT_FLAG_PINNED, &em->flags); |
4e2f84e6 LB |
270 | em->mod_start = em->start; |
271 | em->mod_len = em->len; | |
272 | ||
b11e234d | 273 | if (test_bit(EXTENT_FLAG_FILLING, &em->flags)) { |
4e2f84e6 | 274 | prealloc = true; |
b11e234d | 275 | clear_bit(EXTENT_FLAG_FILLING, &em->flags); |
4e2f84e6 | 276 | } |
4d2c8f62 LZ |
277 | |
278 | try_merge_map(tree, em); | |
4e2f84e6 LB |
279 | |
280 | if (prealloc) { | |
281 | em->mod_start = em->start; | |
282 | em->mod_len = em->len; | |
283 | } | |
284 | ||
a1ed835e CM |
285 | free_extent_map(em); |
286 | out: | |
287 | write_unlock(&tree->lock); | |
288 | return ret; | |
289 | ||
290 | } | |
291 | ||
201a9038 JB |
292 | void clear_em_logging(struct extent_map_tree *tree, struct extent_map *em) |
293 | { | |
294 | clear_bit(EXTENT_FLAG_LOGGING, &em->flags); | |
222c81dc JB |
295 | if (em->in_tree) |
296 | try_merge_map(tree, em); | |
201a9038 JB |
297 | } |
298 | ||
9d2423c5 CH |
299 | /** |
300 | * add_extent_mapping - add new extent map to the extent tree | |
301 | * @tree: tree to insert new map in | |
302 | * @em: map to insert | |
303 | * | |
304 | * Insert @em into @tree or perform a simple forward/backward merge with | |
305 | * existing mappings. The extent_map struct passed in will be inserted | |
306 | * into the tree directly, with an additional reference taken, or a | |
25985edc | 307 | * reference dropped if the merge attempt was successful. |
a52d9a80 CM |
308 | */ |
309 | int add_extent_mapping(struct extent_map_tree *tree, | |
09a2a8f9 | 310 | struct extent_map *em, int modified) |
a52d9a80 CM |
311 | { |
312 | int ret = 0; | |
a52d9a80 | 313 | struct rb_node *rb; |
7c2fe32a | 314 | struct extent_map *exist; |
a52d9a80 | 315 | |
7c2fe32a CM |
316 | exist = lookup_extent_mapping(tree, em->start, em->len); |
317 | if (exist) { | |
318 | free_extent_map(exist); | |
319 | ret = -EEXIST; | |
320 | goto out; | |
321 | } | |
d1310b2e | 322 | rb = tree_insert(&tree->map, em->start, &em->rb_node); |
a52d9a80 | 323 | if (rb) { |
a52d9a80 CM |
324 | ret = -EEXIST; |
325 | goto out; | |
326 | } | |
327 | atomic_inc(&em->refs); | |
4d2c8f62 | 328 | |
4e2f84e6 LB |
329 | em->mod_start = em->start; |
330 | em->mod_len = em->len; | |
331 | ||
09a2a8f9 JB |
332 | if (modified) |
333 | list_move(&em->list, &tree->modified_extents); | |
334 | else | |
335 | try_merge_map(tree, em); | |
a52d9a80 | 336 | out: |
a52d9a80 CM |
337 | return ret; |
338 | } | |
a52d9a80 | 339 | |
d352ac68 | 340 | /* simple helper to do math around the end of an extent, handling wrap */ |
d1310b2e CM |
341 | static u64 range_end(u64 start, u64 len) |
342 | { | |
343 | if (start + len < start) | |
344 | return (u64)-1; | |
345 | return start + len; | |
346 | } | |
347 | ||
48a3b636 ES |
348 | static struct extent_map * |
349 | __lookup_extent_mapping(struct extent_map_tree *tree, | |
350 | u64 start, u64 len, int strict) | |
a52d9a80 CM |
351 | { |
352 | struct extent_map *em; | |
353 | struct rb_node *rb_node; | |
306929f3 CH |
354 | struct rb_node *prev = NULL; |
355 | struct rb_node *next = NULL; | |
356 | u64 end = range_end(start, len); | |
357 | ||
5f56406a | 358 | rb_node = __tree_search(&tree->map, start, &prev, &next); |
a52d9a80 | 359 | if (!rb_node) { |
ed64f066 LZ |
360 | if (prev) |
361 | rb_node = prev; | |
362 | else if (next) | |
363 | rb_node = next; | |
364 | else | |
365 | return NULL; | |
a52d9a80 | 366 | } |
ed64f066 | 367 | |
a52d9a80 | 368 | em = rb_entry(rb_node, struct extent_map, rb_node); |
d1310b2e | 369 | |
ed64f066 LZ |
370 | if (strict && !(end > em->start && start < extent_map_end(em))) |
371 | return NULL; | |
d1310b2e | 372 | |
a52d9a80 | 373 | atomic_inc(&em->refs); |
a52d9a80 CM |
374 | return em; |
375 | } | |
a52d9a80 | 376 | |
ed64f066 LZ |
377 | /** |
378 | * lookup_extent_mapping - lookup extent_map | |
379 | * @tree: tree to lookup in | |
380 | * @start: byte offset to start the search | |
381 | * @len: length of the lookup range | |
382 | * | |
383 | * Find and return the first extent_map struct in @tree that intersects the | |
384 | * [start, len] range. There may be additional objects in the tree that | |
385 | * intersect, so check the object returned carefully to make sure that no | |
386 | * additional lookups are needed. | |
387 | */ | |
388 | struct extent_map *lookup_extent_mapping(struct extent_map_tree *tree, | |
389 | u64 start, u64 len) | |
390 | { | |
391 | return __lookup_extent_mapping(tree, start, len, 1); | |
392 | } | |
393 | ||
b917b7c3 CM |
394 | /** |
395 | * search_extent_mapping - find a nearby extent map | |
396 | * @tree: tree to lookup in | |
397 | * @start: byte offset to start the search | |
398 | * @len: length of the lookup range | |
399 | * | |
400 | * Find and return the first extent_map struct in @tree that intersects the | |
401 | * [start, len] range. | |
402 | * | |
403 | * If one can't be found, any nearby extent may be returned | |
404 | */ | |
405 | struct extent_map *search_extent_mapping(struct extent_map_tree *tree, | |
406 | u64 start, u64 len) | |
407 | { | |
ed64f066 | 408 | return __lookup_extent_mapping(tree, start, len, 0); |
b917b7c3 CM |
409 | } |
410 | ||
9d2423c5 CH |
411 | /** |
412 | * remove_extent_mapping - removes an extent_map from the extent tree | |
413 | * @tree: extent tree to remove from | |
414 | * @em: extent map beeing removed | |
415 | * | |
416 | * Removes @em from @tree. No reference counts are dropped, and no checks | |
417 | * are done to see if the range is in use | |
a52d9a80 CM |
418 | */ |
419 | int remove_extent_mapping(struct extent_map_tree *tree, struct extent_map *em) | |
420 | { | |
d1310b2e | 421 | int ret = 0; |
a52d9a80 | 422 | |
7f3c74fb | 423 | WARN_ON(test_bit(EXTENT_FLAG_PINNED, &em->flags)); |
d1310b2e | 424 | rb_erase(&em->rb_node, &tree->map); |
ff44c6e3 JB |
425 | if (!test_bit(EXTENT_FLAG_LOGGING, &em->flags)) |
426 | list_del_init(&em->list); | |
d1310b2e | 427 | em->in_tree = 0; |
a52d9a80 CM |
428 | return ret; |
429 | } |