1
2
3#include <linux/err.h>
4#include <linux/slab.h>
5#include <linux/spinlock.h>
6#include "ctree.h"
7#include "extent_map.h"
8#include "compression.h"
9
10
11static struct kmem_cache *extent_map_cache;
12
13int __init extent_map_init(void)
14{
15 extent_map_cache = kmem_cache_create("btrfs_extent_map",
16 sizeof(struct extent_map), 0,
17 SLAB_MEM_SPREAD, NULL);
18 if (!extent_map_cache)
19 return -ENOMEM;
20 return 0;
21}
22
23void __cold extent_map_exit(void)
24{
25 kmem_cache_destroy(extent_map_cache);
26}
27
28
29
30
31
32
33
34
35void extent_map_tree_init(struct extent_map_tree *tree)
36{
37 tree->map = RB_ROOT;
38 INIT_LIST_HEAD(&tree->modified_extents);
39 rwlock_init(&tree->lock);
40}
41
42
43
44
45
46
47
48
49struct extent_map *alloc_extent_map(void)
50{
51 struct extent_map *em;
52 em = kmem_cache_zalloc(extent_map_cache, GFP_NOFS);
53 if (!em)
54 return NULL;
55 RB_CLEAR_NODE(&em->rb_node);
56 em->flags = 0;
57 em->compress_type = BTRFS_COMPRESS_NONE;
58 em->generation = 0;
59 refcount_set(&em->refs, 1);
60 INIT_LIST_HEAD(&em->list);
61 return em;
62}
63
64
65
66
67
68
69
70
71void free_extent_map(struct extent_map *em)
72{
73 if (!em)
74 return;
75 WARN_ON(refcount_read(&em->refs) == 0);
76 if (refcount_dec_and_test(&em->refs)) {
77 WARN_ON(extent_map_in_tree(em));
78 WARN_ON(!list_empty(&em->list));
79 if (test_bit(EXTENT_FLAG_FS_MAPPING, &em->flags))
80 kfree(em->map_lookup);
81 kmem_cache_free(extent_map_cache, em);
82 }
83}
84
85
86static u64 range_end(u64 start, u64 len)
87{
88 if (start + len < start)
89 return (u64)-1;
90 return start + len;
91}
92
93static int tree_insert(struct rb_root *root, struct extent_map *em)
94{
95 struct rb_node **p = &root->rb_node;
96 struct rb_node *parent = NULL;
97 struct extent_map *entry = NULL;
98 struct rb_node *orig_parent = NULL;
99 u64 end = range_end(em->start, em->len);
100
101 while (*p) {
102 parent = *p;
103 entry = rb_entry(parent, struct extent_map, rb_node);
104
105 if (em->start < entry->start)
106 p = &(*p)->rb_left;
107 else if (em->start >= extent_map_end(entry))
108 p = &(*p)->rb_right;
109 else
110 return -EEXIST;
111 }
112
113 orig_parent = parent;
114 while (parent && em->start >= extent_map_end(entry)) {
115 parent = rb_next(parent);
116 entry = rb_entry(parent, struct extent_map, rb_node);
117 }
118 if (parent)
119 if (end > entry->start && em->start < extent_map_end(entry))
120 return -EEXIST;
121
122 parent = orig_parent;
123 entry = rb_entry(parent, struct extent_map, rb_node);
124 while (parent && em->start < entry->start) {
125 parent = rb_prev(parent);
126 entry = rb_entry(parent, struct extent_map, rb_node);
127 }
128 if (parent)
129 if (end > entry->start && em->start < extent_map_end(entry))
130 return -EEXIST;
131
132 rb_link_node(&em->rb_node, orig_parent, p);
133 rb_insert_color(&em->rb_node, root);
134 return 0;
135}
136
137
138
139
140
141static struct rb_node *__tree_search(struct rb_root *root, u64 offset,
142 struct rb_node **prev_ret,
143 struct rb_node **next_ret)
144{
145 struct rb_node *n = root->rb_node;
146 struct rb_node *prev = NULL;
147 struct rb_node *orig_prev = NULL;
148 struct extent_map *entry;
149 struct extent_map *prev_entry = NULL;
150
151 while (n) {
152 entry = rb_entry(n, struct extent_map, rb_node);
153 prev = n;
154 prev_entry = entry;
155
156 if (offset < entry->start)
157 n = n->rb_left;
158 else if (offset >= extent_map_end(entry))
159 n = n->rb_right;
160 else
161 return n;
162 }
163
164 if (prev_ret) {
165 orig_prev = prev;
166 while (prev && offset >= extent_map_end(prev_entry)) {
167 prev = rb_next(prev);
168 prev_entry = rb_entry(prev, struct extent_map, rb_node);
169 }
170 *prev_ret = prev;
171 prev = orig_prev;
172 }
173
174 if (next_ret) {
175 prev_entry = rb_entry(prev, struct extent_map, rb_node);
176 while (prev && offset < prev_entry->start) {
177 prev = rb_prev(prev);
178 prev_entry = rb_entry(prev, struct extent_map, rb_node);
179 }
180 *next_ret = prev;
181 }
182 return NULL;
183}
184
185
186static int mergable_maps(struct extent_map *prev, struct extent_map *next)
187{
188 if (test_bit(EXTENT_FLAG_PINNED, &prev->flags))
189 return 0;
190
191
192
193
194
195 if (test_bit(EXTENT_FLAG_COMPRESSED, &prev->flags))
196 return 0;
197
198 if (test_bit(EXTENT_FLAG_LOGGING, &prev->flags) ||
199 test_bit(EXTENT_FLAG_LOGGING, &next->flags))
200 return 0;
201
202
203
204
205
206
207 if (!list_empty(&prev->list) || !list_empty(&next->list))
208 return 0;
209
210 if (extent_map_end(prev) == next->start &&
211 prev->flags == next->flags &&
212 prev->bdev == next->bdev &&
213 ((next->block_start == EXTENT_MAP_HOLE &&
214 prev->block_start == EXTENT_MAP_HOLE) ||
215 (next->block_start == EXTENT_MAP_INLINE &&
216 prev->block_start == EXTENT_MAP_INLINE) ||
217 (next->block_start == EXTENT_MAP_DELALLOC &&
218 prev->block_start == EXTENT_MAP_DELALLOC) ||
219 (next->block_start < EXTENT_MAP_LAST_BYTE - 1 &&
220 next->block_start == extent_map_block_end(prev)))) {
221 return 1;
222 }
223 return 0;
224}
225
226static void try_merge_map(struct extent_map_tree *tree, struct extent_map *em)
227{
228 struct extent_map *merge = NULL;
229 struct rb_node *rb;
230
231 if (em->start != 0) {
232 rb = rb_prev(&em->rb_node);
233 if (rb)
234 merge = rb_entry(rb, struct extent_map, rb_node);
235 if (rb && mergable_maps(merge, em)) {
236 em->start = merge->start;
237 em->orig_start = merge->orig_start;
238 em->len += merge->len;
239 em->block_len += merge->block_len;
240 em->block_start = merge->block_start;
241 em->mod_len = (em->mod_len + em->mod_start) - merge->mod_start;
242 em->mod_start = merge->mod_start;
243 em->generation = max(em->generation, merge->generation);
244
245 rb_erase(&merge->rb_node, &tree->map);
246 RB_CLEAR_NODE(&merge->rb_node);
247 free_extent_map(merge);
248 }
249 }
250
251 rb = rb_next(&em->rb_node);
252 if (rb)
253 merge = rb_entry(rb, struct extent_map, rb_node);
254 if (rb && mergable_maps(em, merge)) {
255 em->len += merge->len;
256 em->block_len += merge->block_len;
257 rb_erase(&merge->rb_node, &tree->map);
258 RB_CLEAR_NODE(&merge->rb_node);
259 em->mod_len = (merge->mod_start + merge->mod_len) - em->mod_start;
260 em->generation = max(em->generation, merge->generation);
261 free_extent_map(merge);
262 }
263}
264
265
266
267
268
269
270
271
272
273
274
275
276int unpin_extent_cache(struct extent_map_tree *tree, u64 start, u64 len,
277 u64 gen)
278{
279 int ret = 0;
280 struct extent_map *em;
281 bool prealloc = false;
282
283 write_lock(&tree->lock);
284 em = lookup_extent_mapping(tree, start, len);
285
286 WARN_ON(!em || em->start != start);
287
288 if (!em)
289 goto out;
290
291 em->generation = gen;
292 clear_bit(EXTENT_FLAG_PINNED, &em->flags);
293 em->mod_start = em->start;
294 em->mod_len = em->len;
295
296 if (test_bit(EXTENT_FLAG_FILLING, &em->flags)) {
297 prealloc = true;
298 clear_bit(EXTENT_FLAG_FILLING, &em->flags);
299 }
300
301 try_merge_map(tree, em);
302
303 if (prealloc) {
304 em->mod_start = em->start;
305 em->mod_len = em->len;
306 }
307
308 free_extent_map(em);
309out:
310 write_unlock(&tree->lock);
311 return ret;
312
313}
314
315void clear_em_logging(struct extent_map_tree *tree, struct extent_map *em)
316{
317 clear_bit(EXTENT_FLAG_LOGGING, &em->flags);
318 if (extent_map_in_tree(em))
319 try_merge_map(tree, em);
320}
321
322static inline void setup_extent_mapping(struct extent_map_tree *tree,
323 struct extent_map *em,
324 int modified)
325{
326 refcount_inc(&em->refs);
327 em->mod_start = em->start;
328 em->mod_len = em->len;
329
330 if (modified)
331 list_move(&em->list, &tree->modified_extents);
332 else
333 try_merge_map(tree, em);
334}
335
336
337
338
339
340
341
342
343
344
345
346int add_extent_mapping(struct extent_map_tree *tree,
347 struct extent_map *em, int modified)
348{
349 int ret = 0;
350
351 ret = tree_insert(&tree->map, em);
352 if (ret)
353 goto out;
354
355 setup_extent_mapping(tree, em, modified);
356out:
357 return ret;
358}
359
360static struct extent_map *
361__lookup_extent_mapping(struct extent_map_tree *tree,
362 u64 start, u64 len, int strict)
363{
364 struct extent_map *em;
365 struct rb_node *rb_node;
366 struct rb_node *prev = NULL;
367 struct rb_node *next = NULL;
368 u64 end = range_end(start, len);
369
370 rb_node = __tree_search(&tree->map, start, &prev, &next);
371 if (!rb_node) {
372 if (prev)
373 rb_node = prev;
374 else if (next)
375 rb_node = next;
376 else
377 return NULL;
378 }
379
380 em = rb_entry(rb_node, struct extent_map, rb_node);
381
382 if (strict && !(end > em->start && start < extent_map_end(em)))
383 return NULL;
384
385 refcount_inc(&em->refs);
386 return em;
387}
388
389
390
391
392
393
394
395
396
397
398
399
400struct extent_map *lookup_extent_mapping(struct extent_map_tree *tree,
401 u64 start, u64 len)
402{
403 return __lookup_extent_mapping(tree, start, len, 1);
404}
405
406
407
408
409
410
411
412
413
414
415
416
417struct extent_map *search_extent_mapping(struct extent_map_tree *tree,
418 u64 start, u64 len)
419{
420 return __lookup_extent_mapping(tree, start, len, 0);
421}
422
423
424
425
426
427
428
429
430
431int remove_extent_mapping(struct extent_map_tree *tree, struct extent_map *em)
432{
433 int ret = 0;
434
435 WARN_ON(test_bit(EXTENT_FLAG_PINNED, &em->flags));
436 rb_erase(&em->rb_node, &tree->map);
437 if (!test_bit(EXTENT_FLAG_LOGGING, &em->flags))
438 list_del_init(&em->list);
439 RB_CLEAR_NODE(&em->rb_node);
440 return ret;
441}
442
443void replace_extent_mapping(struct extent_map_tree *tree,
444 struct extent_map *cur,
445 struct extent_map *new,
446 int modified)
447{
448 WARN_ON(test_bit(EXTENT_FLAG_PINNED, &cur->flags));
449 ASSERT(extent_map_in_tree(cur));
450 if (!test_bit(EXTENT_FLAG_LOGGING, &cur->flags))
451 list_del_init(&cur->list);
452 rb_replace_node(&cur->rb_node, &new->rb_node, &tree->map);
453 RB_CLEAR_NODE(&cur->rb_node);
454
455 setup_extent_mapping(tree, new, modified);
456}
457
458static struct extent_map *next_extent_map(struct extent_map *em)
459{
460 struct rb_node *next;
461
462 next = rb_next(&em->rb_node);
463 if (!next)
464 return NULL;
465 return container_of(next, struct extent_map, rb_node);
466}
467
468static struct extent_map *prev_extent_map(struct extent_map *em)
469{
470 struct rb_node *prev;
471
472 prev = rb_prev(&em->rb_node);
473 if (!prev)
474 return NULL;
475 return container_of(prev, struct extent_map, rb_node);
476}
477
478
479
480
481
482
483static noinline int merge_extent_mapping(struct extent_map_tree *em_tree,
484 struct extent_map *existing,
485 struct extent_map *em,
486 u64 map_start)
487{
488 struct extent_map *prev;
489 struct extent_map *next;
490 u64 start;
491 u64 end;
492 u64 start_diff;
493
494 BUG_ON(map_start < em->start || map_start >= extent_map_end(em));
495
496 if (existing->start > map_start) {
497 next = existing;
498 prev = prev_extent_map(next);
499 } else {
500 prev = existing;
501 next = next_extent_map(prev);
502 }
503
504 start = prev ? extent_map_end(prev) : em->start;
505 start = max_t(u64, start, em->start);
506 end = next ? next->start : extent_map_end(em);
507 end = min_t(u64, end, extent_map_end(em));
508 start_diff = start - em->start;
509 em->start = start;
510 em->len = end - start;
511 if (em->block_start < EXTENT_MAP_LAST_BYTE &&
512 !test_bit(EXTENT_FLAG_COMPRESSED, &em->flags)) {
513 em->block_start += start_diff;
514 em->block_len = em->len;
515 }
516 return add_extent_mapping(em_tree, em, 0);
517}
518
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538
539int btrfs_add_extent_mapping(struct btrfs_fs_info *fs_info,
540 struct extent_map_tree *em_tree,
541 struct extent_map **em_in, u64 start, u64 len)
542{
543 int ret;
544 struct extent_map *em = *em_in;
545
546 ret = add_extent_mapping(em_tree, em, 0);
547
548
549
550
551 if (ret == -EEXIST) {
552 struct extent_map *existing;
553
554 ret = 0;
555
556 existing = search_extent_mapping(em_tree, start, len);
557
558 trace_btrfs_handle_em_exist(fs_info, existing, em, start, len);
559
560
561
562
563
564 if (start >= existing->start &&
565 start < extent_map_end(existing)) {
566 free_extent_map(em);
567 *em_in = existing;
568 ret = 0;
569 } else {
570 u64 orig_start = em->start;
571 u64 orig_len = em->len;
572
573
574
575
576
577 ret = merge_extent_mapping(em_tree, existing,
578 em, start);
579 if (ret) {
580 free_extent_map(em);
581 *em_in = NULL;
582 WARN_ONCE(ret,
583"unexpected error %d: merge existing(start %llu len %llu) with em(start %llu len %llu)\n",
584 ret, existing->start, existing->len,
585 orig_start, orig_len);
586 }
587 free_extent_map(existing);
588 }
589 }
590
591 ASSERT(ret == 0 || ret == -EEXIST);
592 return ret;
593}
594