Commit | Line | Data |
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b2441318 | 1 | // SPDX-License-Identifier: GPL-2.0 |
c1d7c514 | 2 | |
d1310b2e | 3 | #include <linux/err.h> |
d1310b2e | 4 | #include <linux/slab.h> |
a52d9a80 | 5 | #include <linux/spinlock.h> |
261507a0 | 6 | #include "ctree.h" |
1c11b63e | 7 | #include "volumes.h" |
a52d9a80 | 8 | #include "extent_map.h" |
ebb8765b | 9 | #include "compression.h" |
a52d9a80 | 10 | |
86479a04 | 11 | |
a52d9a80 | 12 | static struct kmem_cache *extent_map_cache; |
ca664626 | 13 | |
2f4cbe64 | 14 | int __init extent_map_init(void) |
a52d9a80 | 15 | { |
837e1972 | 16 | extent_map_cache = kmem_cache_create("btrfs_extent_map", |
9601e3f6 | 17 | sizeof(struct extent_map), 0, |
fba4b697 | 18 | SLAB_MEM_SPREAD, NULL); |
2f4cbe64 WB |
19 | if (!extent_map_cache) |
20 | return -ENOMEM; | |
2f4cbe64 | 21 | return 0; |
a52d9a80 CM |
22 | } |
23 | ||
e67c718b | 24 | void __cold extent_map_exit(void) |
a52d9a80 | 25 | { |
5598e900 | 26 | kmem_cache_destroy(extent_map_cache); |
a52d9a80 CM |
27 | } |
28 | ||
9d2423c5 CH |
29 | /** |
30 | * extent_map_tree_init - initialize extent map tree | |
31 | * @tree: tree to initialize | |
9d2423c5 CH |
32 | * |
33 | * Initialize the extent tree @tree. Should be called for each new inode | |
34 | * or other user of the extent_map interface. | |
35 | */ | |
a8067e02 | 36 | void extent_map_tree_init(struct extent_map_tree *tree) |
a52d9a80 | 37 | { |
07e1ce09 | 38 | tree->map = RB_ROOT_CACHED; |
5dc562c5 | 39 | INIT_LIST_HEAD(&tree->modified_extents); |
890871be | 40 | rwlock_init(&tree->lock); |
a52d9a80 | 41 | } |
a52d9a80 | 42 | |
9d2423c5 CH |
43 | /** |
44 | * alloc_extent_map - allocate new extent map structure | |
9d2423c5 CH |
45 | * |
46 | * Allocate a new extent_map structure. The new structure is | |
47 | * returned with a reference count of one and needs to be | |
48 | * freed using free_extent_map() | |
49 | */ | |
172ddd60 | 50 | struct extent_map *alloc_extent_map(void) |
a52d9a80 CM |
51 | { |
52 | struct extent_map *em; | |
70c8a91c | 53 | em = kmem_cache_zalloc(extent_map_cache, GFP_NOFS); |
c26a9203 TI |
54 | if (!em) |
55 | return NULL; | |
cbc0e928 | 56 | RB_CLEAR_NODE(&em->rb_node); |
d1310b2e | 57 | em->flags = 0; |
261507a0 | 58 | em->compress_type = BTRFS_COMPRESS_NONE; |
5dc562c5 | 59 | em->generation = 0; |
490b54d6 | 60 | refcount_set(&em->refs, 1); |
5dc562c5 | 61 | INIT_LIST_HEAD(&em->list); |
a52d9a80 CM |
62 | return em; |
63 | } | |
a52d9a80 | 64 | |
9d2423c5 CH |
65 | /** |
66 | * free_extent_map - drop reference count of an extent_map | |
01327610 | 67 | * @em: extent map being released |
9d2423c5 CH |
68 | * |
69 | * Drops the reference out on @em by one and free the structure | |
70 | * if the reference count hits zero. | |
71 | */ | |
a52d9a80 CM |
72 | void free_extent_map(struct extent_map *em) |
73 | { | |
2bf5a725 CM |
74 | if (!em) |
75 | return; | |
490b54d6 ER |
76 | WARN_ON(refcount_read(&em->refs) == 0); |
77 | if (refcount_dec_and_test(&em->refs)) { | |
cbc0e928 | 78 | WARN_ON(extent_map_in_tree(em)); |
5dc562c5 | 79 | WARN_ON(!list_empty(&em->list)); |
298a8f9c | 80 | if (test_bit(EXTENT_FLAG_FS_MAPPING, &em->flags)) |
95617d69 | 81 | kfree(em->map_lookup); |
a52d9a80 CM |
82 | kmem_cache_free(extent_map_cache, em); |
83 | } | |
84 | } | |
a52d9a80 | 85 | |
32193c14 FDBM |
86 | /* simple helper to do math around the end of an extent, handling wrap */ |
87 | static u64 range_end(u64 start, u64 len) | |
88 | { | |
89 | if (start + len < start) | |
90 | return (u64)-1; | |
91 | return start + len; | |
92 | } | |
93 | ||
07e1ce09 | 94 | static int tree_insert(struct rb_root_cached *root, struct extent_map *em) |
a52d9a80 | 95 | { |
07e1ce09 | 96 | struct rb_node **p = &root->rb_root.rb_node; |
d397712b | 97 | struct rb_node *parent = NULL; |
32193c14 FDBM |
98 | struct extent_map *entry = NULL; |
99 | struct rb_node *orig_parent = NULL; | |
100 | u64 end = range_end(em->start, em->len); | |
07e1ce09 | 101 | bool leftmost = true; |
a52d9a80 | 102 | |
d397712b | 103 | while (*p) { |
a52d9a80 | 104 | parent = *p; |
d1310b2e CM |
105 | entry = rb_entry(parent, struct extent_map, rb_node); |
106 | ||
07e1ce09 | 107 | if (em->start < entry->start) { |
a52d9a80 | 108 | p = &(*p)->rb_left; |
07e1ce09 | 109 | } else if (em->start >= extent_map_end(entry)) { |
a52d9a80 | 110 | p = &(*p)->rb_right; |
07e1ce09 LB |
111 | leftmost = false; |
112 | } else { | |
32193c14 | 113 | return -EEXIST; |
07e1ce09 | 114 | } |
a52d9a80 CM |
115 | } |
116 | ||
32193c14 FDBM |
117 | orig_parent = parent; |
118 | while (parent && em->start >= extent_map_end(entry)) { | |
119 | parent = rb_next(parent); | |
120 | entry = rb_entry(parent, struct extent_map, rb_node); | |
121 | } | |
122 | if (parent) | |
123 | if (end > entry->start && em->start < extent_map_end(entry)) | |
124 | return -EEXIST; | |
125 | ||
126 | parent = orig_parent; | |
127 | entry = rb_entry(parent, struct extent_map, rb_node); | |
128 | while (parent && em->start < entry->start) { | |
129 | parent = rb_prev(parent); | |
130 | entry = rb_entry(parent, struct extent_map, rb_node); | |
131 | } | |
132 | if (parent) | |
133 | if (end > entry->start && em->start < extent_map_end(entry)) | |
134 | return -EEXIST; | |
135 | ||
32193c14 | 136 | rb_link_node(&em->rb_node, orig_parent, p); |
07e1ce09 | 137 | rb_insert_color_cached(&em->rb_node, root, leftmost); |
32193c14 | 138 | return 0; |
a52d9a80 CM |
139 | } |
140 | ||
d352ac68 CM |
141 | /* |
142 | * search through the tree for an extent_map with a given offset. If | |
143 | * it can't be found, try to find some neighboring extents | |
144 | */ | |
a52d9a80 | 145 | static struct rb_node *__tree_search(struct rb_root *root, u64 offset, |
5f56406a CM |
146 | struct rb_node **prev_ret, |
147 | struct rb_node **next_ret) | |
a52d9a80 | 148 | { |
d397712b | 149 | struct rb_node *n = root->rb_node; |
a52d9a80 | 150 | struct rb_node *prev = NULL; |
5f56406a | 151 | struct rb_node *orig_prev = NULL; |
d1310b2e CM |
152 | struct extent_map *entry; |
153 | struct extent_map *prev_entry = NULL; | |
a52d9a80 | 154 | |
d397712b | 155 | while (n) { |
d1310b2e | 156 | entry = rb_entry(n, struct extent_map, rb_node); |
a52d9a80 CM |
157 | prev = n; |
158 | prev_entry = entry; | |
159 | ||
160 | if (offset < entry->start) | |
161 | n = n->rb_left; | |
d1310b2e | 162 | else if (offset >= extent_map_end(entry)) |
a52d9a80 CM |
163 | n = n->rb_right; |
164 | else | |
165 | return n; | |
166 | } | |
5f56406a CM |
167 | |
168 | if (prev_ret) { | |
169 | orig_prev = prev; | |
d397712b | 170 | while (prev && offset >= extent_map_end(prev_entry)) { |
5f56406a | 171 | prev = rb_next(prev); |
d1310b2e | 172 | prev_entry = rb_entry(prev, struct extent_map, rb_node); |
5f56406a CM |
173 | } |
174 | *prev_ret = prev; | |
175 | prev = orig_prev; | |
176 | } | |
177 | ||
178 | if (next_ret) { | |
d1310b2e | 179 | prev_entry = rb_entry(prev, struct extent_map, rb_node); |
d397712b | 180 | while (prev && offset < prev_entry->start) { |
5f56406a | 181 | prev = rb_prev(prev); |
d1310b2e | 182 | prev_entry = rb_entry(prev, struct extent_map, rb_node); |
5f56406a CM |
183 | } |
184 | *next_ret = prev; | |
a52d9a80 | 185 | } |
a52d9a80 CM |
186 | return NULL; |
187 | } | |
188 | ||
d352ac68 | 189 | /* check to see if two extent_map structs are adjacent and safe to merge */ |
d1310b2e | 190 | static int mergable_maps(struct extent_map *prev, struct extent_map *next) |
a52d9a80 | 191 | { |
7f3c74fb CM |
192 | if (test_bit(EXTENT_FLAG_PINNED, &prev->flags)) |
193 | return 0; | |
194 | ||
c8b97818 CM |
195 | /* |
196 | * don't merge compressed extents, we need to know their | |
197 | * actual size | |
198 | */ | |
199 | if (test_bit(EXTENT_FLAG_COMPRESSED, &prev->flags)) | |
200 | return 0; | |
201 | ||
201a9038 JB |
202 | if (test_bit(EXTENT_FLAG_LOGGING, &prev->flags) || |
203 | test_bit(EXTENT_FLAG_LOGGING, &next->flags)) | |
204 | return 0; | |
205 | ||
09a2a8f9 JB |
206 | /* |
207 | * We don't want to merge stuff that hasn't been written to the log yet | |
208 | * since it may not reflect exactly what is on disk, and that would be | |
209 | * bad. | |
210 | */ | |
211 | if (!list_empty(&prev->list) || !list_empty(&next->list)) | |
212 | return 0; | |
213 | ||
951e05a9 NB |
214 | ASSERT(next->block_start != EXTENT_MAP_DELALLOC && |
215 | prev->block_start != EXTENT_MAP_DELALLOC); | |
216 | ||
d1310b2e CM |
217 | if (extent_map_end(prev) == next->start && |
218 | prev->flags == next->flags && | |
219 | prev->bdev == next->bdev && | |
220 | ((next->block_start == EXTENT_MAP_HOLE && | |
221 | prev->block_start == EXTENT_MAP_HOLE) || | |
222 | (next->block_start == EXTENT_MAP_INLINE && | |
223 | prev->block_start == EXTENT_MAP_INLINE) || | |
d1310b2e CM |
224 | (next->block_start < EXTENT_MAP_LAST_BYTE - 1 && |
225 | next->block_start == extent_map_block_end(prev)))) { | |
226 | return 1; | |
227 | } | |
a52d9a80 CM |
228 | return 0; |
229 | } | |
230 | ||
4d2c8f62 | 231 | static void try_merge_map(struct extent_map_tree *tree, struct extent_map *em) |
a1ed835e | 232 | { |
a1ed835e CM |
233 | struct extent_map *merge = NULL; |
234 | struct rb_node *rb; | |
a1ed835e CM |
235 | |
236 | if (em->start != 0) { | |
237 | rb = rb_prev(&em->rb_node); | |
238 | if (rb) | |
239 | merge = rb_entry(rb, struct extent_map, rb_node); | |
240 | if (rb && mergable_maps(merge, em)) { | |
241 | em->start = merge->start; | |
70c8a91c | 242 | em->orig_start = merge->orig_start; |
a1ed835e CM |
243 | em->len += merge->len; |
244 | em->block_len += merge->block_len; | |
245 | em->block_start = merge->block_start; | |
70c8a91c JB |
246 | em->mod_len = (em->mod_len + em->mod_start) - merge->mod_start; |
247 | em->mod_start = merge->mod_start; | |
248 | em->generation = max(em->generation, merge->generation); | |
5dc562c5 | 249 | |
07e1ce09 | 250 | rb_erase_cached(&merge->rb_node, &tree->map); |
cbc0e928 | 251 | RB_CLEAR_NODE(&merge->rb_node); |
a1ed835e CM |
252 | free_extent_map(merge); |
253 | } | |
254 | } | |
255 | ||
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; | |
d527afe1 | 261 | em->block_len += merge->block_len; |
07e1ce09 | 262 | rb_erase_cached(&merge->rb_node, &tree->map); |
cbc0e928 | 263 | RB_CLEAR_NODE(&merge->rb_node); |
70c8a91c JB |
264 | em->mod_len = (merge->mod_start + merge->mod_len) - em->mod_start; |
265 | em->generation = max(em->generation, merge->generation); | |
a1ed835e CM |
266 | free_extent_map(merge); |
267 | } | |
4d2c8f62 LZ |
268 | } |
269 | ||
5dc562c5 | 270 | /** |
52b1de91 | 271 | * unpin_extent_cache - unpin an extent from the cache |
5dc562c5 JB |
272 | * @tree: tree to unpin the extent in |
273 | * @start: logical offset in the file | |
274 | * @len: length of the extent | |
275 | * @gen: generation that this extent has been modified in | |
5dc562c5 JB |
276 | * |
277 | * Called after an extent has been written to disk properly. Set the generation | |
278 | * to the generation that actually added the file item to the inode so we know | |
279 | * we need to sync this extent when we call fsync(). | |
280 | */ | |
281 | int unpin_extent_cache(struct extent_map_tree *tree, u64 start, u64 len, | |
282 | u64 gen) | |
4d2c8f62 LZ |
283 | { |
284 | int ret = 0; | |
285 | struct extent_map *em; | |
4e2f84e6 | 286 | bool prealloc = false; |
4d2c8f62 LZ |
287 | |
288 | write_lock(&tree->lock); | |
289 | em = lookup_extent_mapping(tree, start, len); | |
290 | ||
291 | WARN_ON(!em || em->start != start); | |
292 | ||
293 | if (!em) | |
294 | goto out; | |
295 | ||
5dc562c5 | 296 | em->generation = gen; |
4d2c8f62 | 297 | clear_bit(EXTENT_FLAG_PINNED, &em->flags); |
4e2f84e6 LB |
298 | em->mod_start = em->start; |
299 | em->mod_len = em->len; | |
300 | ||
b11e234d | 301 | if (test_bit(EXTENT_FLAG_FILLING, &em->flags)) { |
4e2f84e6 | 302 | prealloc = true; |
b11e234d | 303 | clear_bit(EXTENT_FLAG_FILLING, &em->flags); |
4e2f84e6 | 304 | } |
4d2c8f62 LZ |
305 | |
306 | try_merge_map(tree, em); | |
4e2f84e6 LB |
307 | |
308 | if (prealloc) { | |
309 | em->mod_start = em->start; | |
310 | em->mod_len = em->len; | |
311 | } | |
312 | ||
a1ed835e CM |
313 | free_extent_map(em); |
314 | out: | |
315 | write_unlock(&tree->lock); | |
316 | return ret; | |
317 | ||
318 | } | |
319 | ||
201a9038 JB |
320 | void clear_em_logging(struct extent_map_tree *tree, struct extent_map *em) |
321 | { | |
322 | clear_bit(EXTENT_FLAG_LOGGING, &em->flags); | |
cbc0e928 | 323 | if (extent_map_in_tree(em)) |
222c81dc | 324 | try_merge_map(tree, em); |
201a9038 JB |
325 | } |
326 | ||
176840b3 FM |
327 | static inline void setup_extent_mapping(struct extent_map_tree *tree, |
328 | struct extent_map *em, | |
329 | int modified) | |
330 | { | |
490b54d6 | 331 | refcount_inc(&em->refs); |
176840b3 FM |
332 | em->mod_start = em->start; |
333 | em->mod_len = em->len; | |
334 | ||
335 | if (modified) | |
336 | list_move(&em->list, &tree->modified_extents); | |
337 | else | |
338 | try_merge_map(tree, em); | |
339 | } | |
340 | ||
1c11b63e JM |
341 | static void extent_map_device_set_bits(struct extent_map *em, unsigned bits) |
342 | { | |
343 | struct map_lookup *map = em->map_lookup; | |
344 | u64 stripe_size = em->orig_block_len; | |
345 | int i; | |
346 | ||
347 | for (i = 0; i < map->num_stripes; i++) { | |
348 | struct btrfs_bio_stripe *stripe = &map->stripes[i]; | |
349 | struct btrfs_device *device = stripe->dev; | |
350 | ||
351 | set_extent_bits_nowait(&device->alloc_state, stripe->physical, | |
352 | stripe->physical + stripe_size - 1, bits); | |
353 | } | |
354 | } | |
355 | ||
356 | static void extent_map_device_clear_bits(struct extent_map *em, unsigned bits) | |
357 | { | |
358 | struct map_lookup *map = em->map_lookup; | |
359 | u64 stripe_size = em->orig_block_len; | |
360 | int i; | |
361 | ||
362 | for (i = 0; i < map->num_stripes; i++) { | |
363 | struct btrfs_bio_stripe *stripe = &map->stripes[i]; | |
364 | struct btrfs_device *device = stripe->dev; | |
365 | ||
366 | __clear_extent_bit(&device->alloc_state, stripe->physical, | |
367 | stripe->physical + stripe_size - 1, bits, | |
368 | 0, 0, NULL, GFP_NOWAIT, NULL); | |
369 | } | |
370 | } | |
371 | ||
9d2423c5 CH |
372 | /** |
373 | * add_extent_mapping - add new extent map to the extent tree | |
374 | * @tree: tree to insert new map in | |
375 | * @em: map to insert | |
376 | * | |
377 | * Insert @em into @tree or perform a simple forward/backward merge with | |
378 | * existing mappings. The extent_map struct passed in will be inserted | |
379 | * into the tree directly, with an additional reference taken, or a | |
25985edc | 380 | * reference dropped if the merge attempt was successful. |
a52d9a80 CM |
381 | */ |
382 | int add_extent_mapping(struct extent_map_tree *tree, | |
09a2a8f9 | 383 | struct extent_map *em, int modified) |
a52d9a80 CM |
384 | { |
385 | int ret = 0; | |
a52d9a80 | 386 | |
d23ea3fa DS |
387 | lockdep_assert_held_write(&tree->lock); |
388 | ||
32193c14 FDBM |
389 | ret = tree_insert(&tree->map, em); |
390 | if (ret) | |
a52d9a80 | 391 | goto out; |
32193c14 | 392 | |
176840b3 | 393 | setup_extent_mapping(tree, em, modified); |
8811133d | 394 | if (test_bit(EXTENT_FLAG_FS_MAPPING, &em->flags)) { |
1c11b63e | 395 | extent_map_device_set_bits(em, CHUNK_ALLOCATED); |
8811133d NB |
396 | extent_map_device_clear_bits(em, CHUNK_TRIMMED); |
397 | } | |
a52d9a80 | 398 | out: |
a52d9a80 CM |
399 | return ret; |
400 | } | |
a52d9a80 | 401 | |
48a3b636 ES |
402 | static struct extent_map * |
403 | __lookup_extent_mapping(struct extent_map_tree *tree, | |
404 | u64 start, u64 len, int strict) | |
a52d9a80 CM |
405 | { |
406 | struct extent_map *em; | |
407 | struct rb_node *rb_node; | |
306929f3 CH |
408 | struct rb_node *prev = NULL; |
409 | struct rb_node *next = NULL; | |
410 | u64 end = range_end(start, len); | |
411 | ||
07e1ce09 | 412 | rb_node = __tree_search(&tree->map.rb_root, start, &prev, &next); |
a52d9a80 | 413 | if (!rb_node) { |
ed64f066 LZ |
414 | if (prev) |
415 | rb_node = prev; | |
416 | else if (next) | |
417 | rb_node = next; | |
418 | else | |
419 | return NULL; | |
a52d9a80 | 420 | } |
ed64f066 | 421 | |
a52d9a80 | 422 | em = rb_entry(rb_node, struct extent_map, rb_node); |
d1310b2e | 423 | |
ed64f066 LZ |
424 | if (strict && !(end > em->start && start < extent_map_end(em))) |
425 | return NULL; | |
d1310b2e | 426 | |
490b54d6 | 427 | refcount_inc(&em->refs); |
a52d9a80 CM |
428 | return em; |
429 | } | |
a52d9a80 | 430 | |
ed64f066 LZ |
431 | /** |
432 | * lookup_extent_mapping - lookup extent_map | |
433 | * @tree: tree to lookup in | |
434 | * @start: byte offset to start the search | |
435 | * @len: length of the lookup range | |
436 | * | |
437 | * Find and return the first extent_map struct in @tree that intersects the | |
438 | * [start, len] range. There may be additional objects in the tree that | |
439 | * intersect, so check the object returned carefully to make sure that no | |
440 | * additional lookups are needed. | |
441 | */ | |
442 | struct extent_map *lookup_extent_mapping(struct extent_map_tree *tree, | |
443 | u64 start, u64 len) | |
444 | { | |
445 | return __lookup_extent_mapping(tree, start, len, 1); | |
446 | } | |
447 | ||
b917b7c3 CM |
448 | /** |
449 | * search_extent_mapping - find a nearby extent map | |
450 | * @tree: tree to lookup in | |
451 | * @start: byte offset to start the search | |
452 | * @len: length of the lookup range | |
453 | * | |
454 | * Find and return the first extent_map struct in @tree that intersects the | |
455 | * [start, len] range. | |
456 | * | |
457 | * If one can't be found, any nearby extent may be returned | |
458 | */ | |
459 | struct extent_map *search_extent_mapping(struct extent_map_tree *tree, | |
460 | u64 start, u64 len) | |
461 | { | |
ed64f066 | 462 | return __lookup_extent_mapping(tree, start, len, 0); |
b917b7c3 CM |
463 | } |
464 | ||
9d2423c5 CH |
465 | /** |
466 | * remove_extent_mapping - removes an extent_map from the extent tree | |
467 | * @tree: extent tree to remove from | |
bb7ab3b9 | 468 | * @em: extent map being removed |
9d2423c5 CH |
469 | * |
470 | * Removes @em from @tree. No reference counts are dropped, and no checks | |
471 | * are done to see if the range is in use | |
a52d9a80 | 472 | */ |
c1766dd7 | 473 | void remove_extent_mapping(struct extent_map_tree *tree, struct extent_map *em) |
a52d9a80 | 474 | { |
7f3c74fb | 475 | WARN_ON(test_bit(EXTENT_FLAG_PINNED, &em->flags)); |
07e1ce09 | 476 | rb_erase_cached(&em->rb_node, &tree->map); |
ff44c6e3 JB |
477 | if (!test_bit(EXTENT_FLAG_LOGGING, &em->flags)) |
478 | list_del_init(&em->list); | |
1c11b63e JM |
479 | if (test_bit(EXTENT_FLAG_FS_MAPPING, &em->flags)) |
480 | extent_map_device_clear_bits(em, CHUNK_ALLOCATED); | |
cbc0e928 | 481 | RB_CLEAR_NODE(&em->rb_node); |
a52d9a80 | 482 | } |
176840b3 FM |
483 | |
484 | void replace_extent_mapping(struct extent_map_tree *tree, | |
485 | struct extent_map *cur, | |
486 | struct extent_map *new, | |
487 | int modified) | |
488 | { | |
489 | WARN_ON(test_bit(EXTENT_FLAG_PINNED, &cur->flags)); | |
490 | ASSERT(extent_map_in_tree(cur)); | |
491 | if (!test_bit(EXTENT_FLAG_LOGGING, &cur->flags)) | |
492 | list_del_init(&cur->list); | |
07e1ce09 | 493 | rb_replace_node_cached(&cur->rb_node, &new->rb_node, &tree->map); |
176840b3 FM |
494 | RB_CLEAR_NODE(&cur->rb_node); |
495 | ||
496 | setup_extent_mapping(tree, new, modified); | |
497 | } | |
c04e61b5 LB |
498 | |
499 | static struct extent_map *next_extent_map(struct extent_map *em) | |
500 | { | |
501 | struct rb_node *next; | |
502 | ||
503 | next = rb_next(&em->rb_node); | |
504 | if (!next) | |
505 | return NULL; | |
506 | return container_of(next, struct extent_map, rb_node); | |
507 | } | |
508 | ||
509 | static struct extent_map *prev_extent_map(struct extent_map *em) | |
510 | { | |
511 | struct rb_node *prev; | |
512 | ||
513 | prev = rb_prev(&em->rb_node); | |
514 | if (!prev) | |
515 | return NULL; | |
516 | return container_of(prev, struct extent_map, rb_node); | |
517 | } | |
518 | ||
52042d8e AG |
519 | /* |
520 | * Helper for btrfs_get_extent. Given an existing extent in the tree, | |
c04e61b5 LB |
521 | * the existing extent is the nearest extent to map_start, |
522 | * and an extent that you want to insert, deal with overlap and insert | |
523 | * the best fitted new extent into the tree. | |
524 | */ | |
5f4791f4 LB |
525 | static noinline int merge_extent_mapping(struct extent_map_tree *em_tree, |
526 | struct extent_map *existing, | |
527 | struct extent_map *em, | |
528 | u64 map_start) | |
c04e61b5 LB |
529 | { |
530 | struct extent_map *prev; | |
531 | struct extent_map *next; | |
532 | u64 start; | |
533 | u64 end; | |
534 | u64 start_diff; | |
535 | ||
536 | BUG_ON(map_start < em->start || map_start >= extent_map_end(em)); | |
537 | ||
538 | if (existing->start > map_start) { | |
539 | next = existing; | |
540 | prev = prev_extent_map(next); | |
541 | } else { | |
542 | prev = existing; | |
543 | next = next_extent_map(prev); | |
544 | } | |
545 | ||
546 | start = prev ? extent_map_end(prev) : em->start; | |
547 | start = max_t(u64, start, em->start); | |
548 | end = next ? next->start : extent_map_end(em); | |
549 | end = min_t(u64, end, extent_map_end(em)); | |
550 | start_diff = start - em->start; | |
551 | em->start = start; | |
552 | em->len = end - start; | |
553 | if (em->block_start < EXTENT_MAP_LAST_BYTE && | |
554 | !test_bit(EXTENT_FLAG_COMPRESSED, &em->flags)) { | |
555 | em->block_start += start_diff; | |
556 | em->block_len = em->len; | |
557 | } | |
558 | return add_extent_mapping(em_tree, em, 0); | |
559 | } | |
560 | ||
561 | /** | |
562 | * btrfs_add_extent_mapping - add extent mapping into em_tree | |
f46b24c9 | 563 | * @fs_info - used for tracepoint |
c04e61b5 LB |
564 | * @em_tree - the extent tree into which we want to insert the extent mapping |
565 | * @em_in - extent we are inserting | |
566 | * @start - start of the logical range btrfs_get_extent() is requesting | |
567 | * @len - length of the logical range btrfs_get_extent() is requesting | |
568 | * | |
569 | * Note that @em_in's range may be different from [start, start+len), | |
570 | * but they must be overlapped. | |
571 | * | |
572 | * Insert @em_in into @em_tree. In case there is an overlapping range, handle | |
573 | * the -EEXIST by either: | |
574 | * a) Returning the existing extent in @em_in if @start is within the | |
575 | * existing em. | |
576 | * b) Merge the existing extent with @em_in passed in. | |
577 | * | |
578 | * Return 0 on success, otherwise -EEXIST. | |
579 | * | |
580 | */ | |
f46b24c9 DS |
581 | int btrfs_add_extent_mapping(struct btrfs_fs_info *fs_info, |
582 | struct extent_map_tree *em_tree, | |
c04e61b5 LB |
583 | struct extent_map **em_in, u64 start, u64 len) |
584 | { | |
585 | int ret; | |
586 | struct extent_map *em = *em_in; | |
587 | ||
588 | ret = add_extent_mapping(em_tree, em, 0); | |
589 | /* it is possible that someone inserted the extent into the tree | |
590 | * while we had the lock dropped. It is also possible that | |
591 | * an overlapping map exists in the tree | |
592 | */ | |
593 | if (ret == -EEXIST) { | |
594 | struct extent_map *existing; | |
595 | ||
596 | ret = 0; | |
597 | ||
598 | existing = search_extent_mapping(em_tree, start, len); | |
393da918 | 599 | |
f46b24c9 | 600 | trace_btrfs_handle_em_exist(fs_info, existing, em, start, len); |
393da918 | 601 | |
c04e61b5 LB |
602 | /* |
603 | * existing will always be non-NULL, since there must be | |
604 | * extent causing the -EEXIST. | |
605 | */ | |
606 | if (start >= existing->start && | |
607 | start < extent_map_end(existing)) { | |
608 | free_extent_map(em); | |
609 | *em_in = existing; | |
610 | ret = 0; | |
611 | } else { | |
9a7e10e7 LB |
612 | u64 orig_start = em->start; |
613 | u64 orig_len = em->len; | |
614 | ||
c04e61b5 LB |
615 | /* |
616 | * The existing extent map is the one nearest to | |
617 | * the [start, start + len) range which overlaps | |
618 | */ | |
619 | ret = merge_extent_mapping(em_tree, existing, | |
620 | em, start); | |
c04e61b5 LB |
621 | if (ret) { |
622 | free_extent_map(em); | |
623 | *em_in = NULL; | |
9a7e10e7 LB |
624 | WARN_ONCE(ret, |
625 | "unexpected error %d: merge existing(start %llu len %llu) with em(start %llu len %llu)\n", | |
626 | ret, existing->start, existing->len, | |
627 | orig_start, orig_len); | |
c04e61b5 | 628 | } |
9a7e10e7 | 629 | free_extent_map(existing); |
c04e61b5 LB |
630 | } |
631 | } | |
632 | ||
633 | ASSERT(ret == 0 || ret == -EEXIST); | |
634 | return ret; | |
635 | } |