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0f9dd46c JB |
1 | /* |
2 | * Copyright (C) 2008 Red Hat. All rights reserved. | |
3 | * | |
4 | * This program is free software; you can redistribute it and/or | |
5 | * modify it under the terms of the GNU General Public | |
6 | * License v2 as published by the Free Software Foundation. | |
7 | * | |
8 | * This program is distributed in the hope that it will be useful, | |
9 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
10 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
11 | * General Public License for more details. | |
12 | * | |
13 | * You should have received a copy of the GNU General Public | |
14 | * License along with this program; if not, write to the | |
15 | * Free Software Foundation, Inc., 59 Temple Place - Suite 330, | |
16 | * Boston, MA 021110-1307, USA. | |
17 | */ | |
18 | ||
19 | #include <linux/sched.h> | |
20 | #include "ctree.h" | |
fa9c0d79 CM |
21 | #include "free-space-cache.h" |
22 | #include "transaction.h" | |
23 | ||
24 | struct btrfs_free_space { | |
25 | struct rb_node bytes_index; | |
26 | struct rb_node offset_index; | |
27 | u64 offset; | |
28 | u64 bytes; | |
29 | }; | |
0f9dd46c JB |
30 | |
31 | static int tree_insert_offset(struct rb_root *root, u64 offset, | |
32 | struct rb_node *node) | |
33 | { | |
34 | struct rb_node **p = &root->rb_node; | |
35 | struct rb_node *parent = NULL; | |
36 | struct btrfs_free_space *info; | |
37 | ||
38 | while (*p) { | |
39 | parent = *p; | |
40 | info = rb_entry(parent, struct btrfs_free_space, offset_index); | |
41 | ||
42 | if (offset < info->offset) | |
43 | p = &(*p)->rb_left; | |
44 | else if (offset > info->offset) | |
45 | p = &(*p)->rb_right; | |
46 | else | |
47 | return -EEXIST; | |
48 | } | |
49 | ||
50 | rb_link_node(node, parent, p); | |
51 | rb_insert_color(node, root); | |
52 | ||
53 | return 0; | |
54 | } | |
55 | ||
56 | static int tree_insert_bytes(struct rb_root *root, u64 bytes, | |
57 | struct rb_node *node) | |
58 | { | |
59 | struct rb_node **p = &root->rb_node; | |
60 | struct rb_node *parent = NULL; | |
61 | struct btrfs_free_space *info; | |
62 | ||
63 | while (*p) { | |
64 | parent = *p; | |
65 | info = rb_entry(parent, struct btrfs_free_space, bytes_index); | |
66 | ||
67 | if (bytes < info->bytes) | |
68 | p = &(*p)->rb_left; | |
69 | else | |
70 | p = &(*p)->rb_right; | |
71 | } | |
72 | ||
73 | rb_link_node(node, parent, p); | |
74 | rb_insert_color(node, root); | |
75 | ||
76 | return 0; | |
77 | } | |
78 | ||
79 | /* | |
70cb0743 JB |
80 | * searches the tree for the given offset. |
81 | * | |
82 | * fuzzy == 1: this is used for allocations where we are given a hint of where | |
83 | * to look for free space. Because the hint may not be completely on an offset | |
84 | * mark, or the hint may no longer point to free space we need to fudge our | |
85 | * results a bit. So we look for free space starting at or after offset with at | |
86 | * least bytes size. We prefer to find as close to the given offset as we can. | |
87 | * Also if the offset is within a free space range, then we will return the free | |
88 | * space that contains the given offset, which means we can return a free space | |
89 | * chunk with an offset before the provided offset. | |
90 | * | |
91 | * fuzzy == 0: this is just a normal tree search. Give us the free space that | |
92 | * starts at the given offset which is at least bytes size, and if its not there | |
93 | * return NULL. | |
0f9dd46c JB |
94 | */ |
95 | static struct btrfs_free_space *tree_search_offset(struct rb_root *root, | |
96 | u64 offset, u64 bytes, | |
70cb0743 | 97 | int fuzzy) |
0f9dd46c JB |
98 | { |
99 | struct rb_node *n = root->rb_node; | |
100 | struct btrfs_free_space *entry, *ret = NULL; | |
101 | ||
102 | while (n) { | |
103 | entry = rb_entry(n, struct btrfs_free_space, offset_index); | |
104 | ||
105 | if (offset < entry->offset) { | |
70cb0743 | 106 | if (fuzzy && |
0f9dd46c JB |
107 | (!ret || entry->offset < ret->offset) && |
108 | (bytes <= entry->bytes)) | |
109 | ret = entry; | |
110 | n = n->rb_left; | |
111 | } else if (offset > entry->offset) { | |
70cb0743 JB |
112 | if (fuzzy && |
113 | (entry->offset + entry->bytes - 1) >= offset && | |
37d3cddd | 114 | bytes <= entry->bytes) { |
0f9dd46c JB |
115 | ret = entry; |
116 | break; | |
117 | } | |
118 | n = n->rb_right; | |
119 | } else { | |
120 | if (bytes > entry->bytes) { | |
121 | n = n->rb_right; | |
122 | continue; | |
123 | } | |
124 | ret = entry; | |
125 | break; | |
126 | } | |
127 | } | |
128 | ||
129 | return ret; | |
130 | } | |
131 | ||
132 | /* | |
133 | * return a chunk at least bytes size, as close to offset that we can get. | |
134 | */ | |
135 | static struct btrfs_free_space *tree_search_bytes(struct rb_root *root, | |
136 | u64 offset, u64 bytes) | |
137 | { | |
138 | struct rb_node *n = root->rb_node; | |
139 | struct btrfs_free_space *entry, *ret = NULL; | |
140 | ||
141 | while (n) { | |
142 | entry = rb_entry(n, struct btrfs_free_space, bytes_index); | |
143 | ||
144 | if (bytes < entry->bytes) { | |
145 | /* | |
146 | * We prefer to get a hole size as close to the size we | |
147 | * are asking for so we don't take small slivers out of | |
148 | * huge holes, but we also want to get as close to the | |
149 | * offset as possible so we don't have a whole lot of | |
150 | * fragmentation. | |
151 | */ | |
152 | if (offset <= entry->offset) { | |
153 | if (!ret) | |
154 | ret = entry; | |
155 | else if (entry->bytes < ret->bytes) | |
156 | ret = entry; | |
157 | else if (entry->offset < ret->offset) | |
158 | ret = entry; | |
159 | } | |
160 | n = n->rb_left; | |
161 | } else if (bytes > entry->bytes) { | |
162 | n = n->rb_right; | |
163 | } else { | |
164 | /* | |
165 | * Ok we may have multiple chunks of the wanted size, | |
166 | * so we don't want to take the first one we find, we | |
167 | * want to take the one closest to our given offset, so | |
168 | * keep searching just in case theres a better match. | |
169 | */ | |
170 | n = n->rb_right; | |
171 | if (offset > entry->offset) | |
172 | continue; | |
173 | else if (!ret || entry->offset < ret->offset) | |
174 | ret = entry; | |
175 | } | |
176 | } | |
177 | ||
178 | return ret; | |
179 | } | |
180 | ||
181 | static void unlink_free_space(struct btrfs_block_group_cache *block_group, | |
182 | struct btrfs_free_space *info) | |
183 | { | |
184 | rb_erase(&info->offset_index, &block_group->free_space_offset); | |
185 | rb_erase(&info->bytes_index, &block_group->free_space_bytes); | |
186 | } | |
187 | ||
188 | static int link_free_space(struct btrfs_block_group_cache *block_group, | |
189 | struct btrfs_free_space *info) | |
190 | { | |
191 | int ret = 0; | |
192 | ||
193 | ||
6226cb0a | 194 | BUG_ON(!info->bytes); |
0f9dd46c JB |
195 | ret = tree_insert_offset(&block_group->free_space_offset, info->offset, |
196 | &info->offset_index); | |
197 | if (ret) | |
198 | return ret; | |
199 | ||
200 | ret = tree_insert_bytes(&block_group->free_space_bytes, info->bytes, | |
201 | &info->bytes_index); | |
202 | if (ret) | |
203 | return ret; | |
204 | ||
205 | return ret; | |
206 | } | |
207 | ||
6226cb0a JB |
208 | int btrfs_add_free_space(struct btrfs_block_group_cache *block_group, |
209 | u64 offset, u64 bytes) | |
0f9dd46c JB |
210 | { |
211 | struct btrfs_free_space *right_info; | |
212 | struct btrfs_free_space *left_info; | |
213 | struct btrfs_free_space *info = NULL; | |
0f9dd46c JB |
214 | int ret = 0; |
215 | ||
6226cb0a JB |
216 | info = kzalloc(sizeof(struct btrfs_free_space), GFP_NOFS); |
217 | if (!info) | |
218 | return -ENOMEM; | |
219 | ||
220 | info->offset = offset; | |
221 | info->bytes = bytes; | |
222 | ||
223 | spin_lock(&block_group->tree_lock); | |
224 | ||
0f9dd46c JB |
225 | /* |
226 | * first we want to see if there is free space adjacent to the range we | |
227 | * are adding, if there is remove that struct and add a new one to | |
228 | * cover the entire range | |
229 | */ | |
0f9dd46c | 230 | right_info = tree_search_offset(&block_group->free_space_offset, |
70cb0743 | 231 | offset+bytes, 0, 0); |
0f9dd46c JB |
232 | left_info = tree_search_offset(&block_group->free_space_offset, |
233 | offset-1, 0, 1); | |
234 | ||
70cb0743 | 235 | if (right_info) { |
0f9dd46c | 236 | unlink_free_space(block_group, right_info); |
6226cb0a JB |
237 | info->bytes += right_info->bytes; |
238 | kfree(right_info); | |
0f9dd46c JB |
239 | } |
240 | ||
70cb0743 | 241 | if (left_info && left_info->offset + left_info->bytes == offset) { |
0f9dd46c | 242 | unlink_free_space(block_group, left_info); |
6226cb0a JB |
243 | info->offset = left_info->offset; |
244 | info->bytes += left_info->bytes; | |
245 | kfree(left_info); | |
0f9dd46c JB |
246 | } |
247 | ||
0f9dd46c JB |
248 | ret = link_free_space(block_group, info); |
249 | if (ret) | |
250 | kfree(info); | |
6226cb0a JB |
251 | |
252 | spin_unlock(&block_group->tree_lock); | |
253 | ||
0f9dd46c JB |
254 | if (ret) { |
255 | printk(KERN_ERR "btrfs: unable to add free space :%d\n", ret); | |
c293498b | 256 | BUG_ON(ret == -EEXIST); |
0f9dd46c JB |
257 | } |
258 | ||
0f9dd46c JB |
259 | return ret; |
260 | } | |
261 | ||
6226cb0a JB |
262 | int btrfs_remove_free_space(struct btrfs_block_group_cache *block_group, |
263 | u64 offset, u64 bytes) | |
0f9dd46c JB |
264 | { |
265 | struct btrfs_free_space *info; | |
266 | int ret = 0; | |
267 | ||
6226cb0a JB |
268 | spin_lock(&block_group->tree_lock); |
269 | ||
0f9dd46c JB |
270 | info = tree_search_offset(&block_group->free_space_offset, offset, 0, |
271 | 1); | |
0f9dd46c JB |
272 | if (info && info->offset == offset) { |
273 | if (info->bytes < bytes) { | |
d397712b CM |
274 | printk(KERN_ERR "Found free space at %llu, size %llu," |
275 | "trying to use %llu\n", | |
276 | (unsigned long long)info->offset, | |
277 | (unsigned long long)info->bytes, | |
278 | (unsigned long long)bytes); | |
0f9dd46c JB |
279 | WARN_ON(1); |
280 | ret = -EINVAL; | |
6226cb0a | 281 | spin_unlock(&block_group->tree_lock); |
0f9dd46c JB |
282 | goto out; |
283 | } | |
0f9dd46c JB |
284 | unlink_free_space(block_group, info); |
285 | ||
286 | if (info->bytes == bytes) { | |
287 | kfree(info); | |
6226cb0a | 288 | spin_unlock(&block_group->tree_lock); |
0f9dd46c JB |
289 | goto out; |
290 | } | |
291 | ||
292 | info->offset += bytes; | |
293 | info->bytes -= bytes; | |
294 | ||
295 | ret = link_free_space(block_group, info); | |
6226cb0a | 296 | spin_unlock(&block_group->tree_lock); |
0f9dd46c | 297 | BUG_ON(ret); |
9b49c9b9 CM |
298 | } else if (info && info->offset < offset && |
299 | info->offset + info->bytes >= offset + bytes) { | |
300 | u64 old_start = info->offset; | |
301 | /* | |
302 | * we're freeing space in the middle of the info, | |
303 | * this can happen during tree log replay | |
304 | * | |
305 | * first unlink the old info and then | |
306 | * insert it again after the hole we're creating | |
307 | */ | |
308 | unlink_free_space(block_group, info); | |
309 | if (offset + bytes < info->offset + info->bytes) { | |
310 | u64 old_end = info->offset + info->bytes; | |
311 | ||
312 | info->offset = offset + bytes; | |
313 | info->bytes = old_end - info->offset; | |
314 | ret = link_free_space(block_group, info); | |
315 | BUG_ON(ret); | |
316 | } else { | |
317 | /* the hole we're creating ends at the end | |
318 | * of the info struct, just free the info | |
319 | */ | |
320 | kfree(info); | |
321 | } | |
6226cb0a | 322 | spin_unlock(&block_group->tree_lock); |
9b49c9b9 CM |
323 | /* step two, insert a new info struct to cover anything |
324 | * before the hole | |
325 | */ | |
6226cb0a JB |
326 | ret = btrfs_add_free_space(block_group, old_start, |
327 | offset - old_start); | |
9b49c9b9 | 328 | BUG_ON(ret); |
0f9dd46c | 329 | } else { |
6226cb0a | 330 | spin_unlock(&block_group->tree_lock); |
70cb0743 JB |
331 | if (!info) { |
332 | printk(KERN_ERR "couldn't find space %llu to free\n", | |
333 | (unsigned long long)offset); | |
334 | printk(KERN_ERR "cached is %d, offset %llu bytes %llu\n", | |
21380931 JB |
335 | block_group->cached, |
336 | (unsigned long long)block_group->key.objectid, | |
337 | (unsigned long long)block_group->key.offset); | |
70cb0743 JB |
338 | btrfs_dump_free_space(block_group, bytes); |
339 | } else if (info) { | |
340 | printk(KERN_ERR "hmm, found offset=%llu bytes=%llu, " | |
341 | "but wanted offset=%llu bytes=%llu\n", | |
21380931 JB |
342 | (unsigned long long)info->offset, |
343 | (unsigned long long)info->bytes, | |
344 | (unsigned long long)offset, | |
345 | (unsigned long long)bytes); | |
70cb0743 | 346 | } |
0f9dd46c JB |
347 | WARN_ON(1); |
348 | } | |
349 | out: | |
25179201 JB |
350 | return ret; |
351 | } | |
352 | ||
0f9dd46c JB |
353 | void btrfs_dump_free_space(struct btrfs_block_group_cache *block_group, |
354 | u64 bytes) | |
355 | { | |
356 | struct btrfs_free_space *info; | |
357 | struct rb_node *n; | |
358 | int count = 0; | |
359 | ||
360 | for (n = rb_first(&block_group->free_space_offset); n; n = rb_next(n)) { | |
361 | info = rb_entry(n, struct btrfs_free_space, offset_index); | |
362 | if (info->bytes >= bytes) | |
363 | count++; | |
21380931 JB |
364 | printk(KERN_ERR "entry offset %llu, bytes %llu\n", |
365 | (unsigned long long)info->offset, | |
366 | (unsigned long long)info->bytes); | |
0f9dd46c JB |
367 | } |
368 | printk(KERN_INFO "%d blocks of free space at or bigger than bytes is" | |
369 | "\n", count); | |
370 | } | |
371 | ||
372 | u64 btrfs_block_group_free_space(struct btrfs_block_group_cache *block_group) | |
373 | { | |
374 | struct btrfs_free_space *info; | |
375 | struct rb_node *n; | |
376 | u64 ret = 0; | |
377 | ||
378 | for (n = rb_first(&block_group->free_space_offset); n; | |
379 | n = rb_next(n)) { | |
380 | info = rb_entry(n, struct btrfs_free_space, offset_index); | |
381 | ret += info->bytes; | |
382 | } | |
383 | ||
384 | return ret; | |
385 | } | |
386 | ||
fa9c0d79 CM |
387 | /* |
388 | * for a given cluster, put all of its extents back into the free | |
389 | * space cache. If the block group passed doesn't match the block group | |
390 | * pointed to by the cluster, someone else raced in and freed the | |
391 | * cluster already. In that case, we just return without changing anything | |
392 | */ | |
393 | static int | |
394 | __btrfs_return_cluster_to_free_space( | |
395 | struct btrfs_block_group_cache *block_group, | |
396 | struct btrfs_free_cluster *cluster) | |
397 | { | |
398 | struct btrfs_free_space *entry; | |
399 | struct rb_node *node; | |
400 | ||
401 | spin_lock(&cluster->lock); | |
402 | if (cluster->block_group != block_group) | |
403 | goto out; | |
404 | ||
405 | cluster->window_start = 0; | |
406 | node = rb_first(&cluster->root); | |
407 | while(node) { | |
408 | entry = rb_entry(node, struct btrfs_free_space, offset_index); | |
409 | node = rb_next(&entry->offset_index); | |
410 | rb_erase(&entry->offset_index, &cluster->root); | |
411 | link_free_space(block_group, entry); | |
412 | } | |
413 | list_del_init(&cluster->block_group_list); | |
414 | ||
415 | btrfs_put_block_group(cluster->block_group); | |
416 | cluster->block_group = NULL; | |
417 | cluster->root.rb_node = NULL; | |
418 | out: | |
419 | spin_unlock(&cluster->lock); | |
420 | return 0; | |
421 | } | |
422 | ||
0f9dd46c JB |
423 | void btrfs_remove_free_space_cache(struct btrfs_block_group_cache *block_group) |
424 | { | |
425 | struct btrfs_free_space *info; | |
426 | struct rb_node *node; | |
fa9c0d79 CM |
427 | struct btrfs_free_cluster *cluster; |
428 | struct btrfs_free_cluster *safe; | |
0f9dd46c | 429 | |
6226cb0a | 430 | spin_lock(&block_group->tree_lock); |
fa9c0d79 CM |
431 | |
432 | list_for_each_entry_safe(cluster, safe, &block_group->cluster_list, | |
433 | block_group_list) { | |
434 | ||
435 | WARN_ON(cluster->block_group != block_group); | |
436 | __btrfs_return_cluster_to_free_space(block_group, cluster); | |
437 | } | |
438 | ||
0f9dd46c JB |
439 | while ((node = rb_last(&block_group->free_space_bytes)) != NULL) { |
440 | info = rb_entry(node, struct btrfs_free_space, bytes_index); | |
441 | unlink_free_space(block_group, info); | |
442 | kfree(info); | |
443 | if (need_resched()) { | |
6226cb0a | 444 | spin_unlock(&block_group->tree_lock); |
0f9dd46c | 445 | cond_resched(); |
6226cb0a | 446 | spin_lock(&block_group->tree_lock); |
0f9dd46c JB |
447 | } |
448 | } | |
6226cb0a | 449 | spin_unlock(&block_group->tree_lock); |
0f9dd46c JB |
450 | } |
451 | ||
6226cb0a JB |
452 | u64 btrfs_find_space_for_alloc(struct btrfs_block_group_cache *block_group, |
453 | u64 offset, u64 bytes, u64 empty_size) | |
0f9dd46c | 454 | { |
6226cb0a JB |
455 | struct btrfs_free_space *entry = NULL; |
456 | u64 ret = 0; | |
0f9dd46c | 457 | |
6226cb0a JB |
458 | spin_lock(&block_group->tree_lock); |
459 | entry = tree_search_offset(&block_group->free_space_offset, offset, | |
460 | bytes + empty_size, 1); | |
461 | if (!entry) | |
462 | entry = tree_search_bytes(&block_group->free_space_bytes, | |
463 | offset, bytes + empty_size); | |
464 | if (entry) { | |
465 | unlink_free_space(block_group, entry); | |
466 | ret = entry->offset; | |
467 | entry->offset += bytes; | |
468 | entry->bytes -= bytes; | |
469 | ||
470 | if (!entry->bytes) | |
471 | kfree(entry); | |
472 | else | |
473 | link_free_space(block_group, entry); | |
474 | } | |
475 | spin_unlock(&block_group->tree_lock); | |
0f9dd46c | 476 | |
0f9dd46c JB |
477 | return ret; |
478 | } | |
fa9c0d79 CM |
479 | |
480 | /* | |
481 | * given a cluster, put all of its extents back into the free space | |
482 | * cache. If a block group is passed, this function will only free | |
483 | * a cluster that belongs to the passed block group. | |
484 | * | |
485 | * Otherwise, it'll get a reference on the block group pointed to by the | |
486 | * cluster and remove the cluster from it. | |
487 | */ | |
488 | int btrfs_return_cluster_to_free_space( | |
489 | struct btrfs_block_group_cache *block_group, | |
490 | struct btrfs_free_cluster *cluster) | |
491 | { | |
492 | int ret; | |
493 | ||
494 | /* first, get a safe pointer to the block group */ | |
495 | spin_lock(&cluster->lock); | |
496 | if (!block_group) { | |
497 | block_group = cluster->block_group; | |
498 | if (!block_group) { | |
499 | spin_unlock(&cluster->lock); | |
500 | return 0; | |
501 | } | |
502 | } else if (cluster->block_group != block_group) { | |
503 | /* someone else has already freed it don't redo their work */ | |
504 | spin_unlock(&cluster->lock); | |
505 | return 0; | |
506 | } | |
507 | atomic_inc(&block_group->count); | |
508 | spin_unlock(&cluster->lock); | |
509 | ||
510 | /* now return any extents the cluster had on it */ | |
511 | spin_lock(&block_group->tree_lock); | |
512 | ret = __btrfs_return_cluster_to_free_space(block_group, cluster); | |
513 | spin_unlock(&block_group->tree_lock); | |
514 | ||
515 | /* finally drop our ref */ | |
516 | btrfs_put_block_group(block_group); | |
517 | return ret; | |
518 | } | |
519 | ||
520 | /* | |
521 | * given a cluster, try to allocate 'bytes' from it, returns 0 | |
522 | * if it couldn't find anything suitably large, or a logical disk offset | |
523 | * if things worked out | |
524 | */ | |
525 | u64 btrfs_alloc_from_cluster(struct btrfs_block_group_cache *block_group, | |
526 | struct btrfs_free_cluster *cluster, u64 bytes, | |
527 | u64 min_start) | |
528 | { | |
529 | struct btrfs_free_space *entry = NULL; | |
530 | struct rb_node *node; | |
531 | u64 ret = 0; | |
532 | ||
533 | spin_lock(&cluster->lock); | |
534 | if (bytes > cluster->max_size) | |
535 | goto out; | |
536 | ||
537 | if (cluster->block_group != block_group) | |
538 | goto out; | |
539 | ||
540 | node = rb_first(&cluster->root); | |
541 | if (!node) | |
542 | goto out; | |
543 | ||
544 | entry = rb_entry(node, struct btrfs_free_space, offset_index); | |
545 | ||
546 | while(1) { | |
547 | if (entry->bytes < bytes || entry->offset < min_start) { | |
548 | struct rb_node *node; | |
549 | ||
550 | node = rb_next(&entry->offset_index); | |
551 | if (!node) | |
552 | break; | |
553 | entry = rb_entry(node, struct btrfs_free_space, | |
554 | offset_index); | |
555 | continue; | |
556 | } | |
557 | ret = entry->offset; | |
558 | ||
559 | entry->offset += bytes; | |
560 | entry->bytes -= bytes; | |
561 | ||
562 | if (entry->bytes == 0) { | |
563 | rb_erase(&entry->offset_index, &cluster->root); | |
564 | kfree(entry); | |
565 | } | |
566 | break; | |
567 | } | |
568 | out: | |
569 | spin_unlock(&cluster->lock); | |
570 | return ret; | |
571 | } | |
572 | ||
573 | /* | |
574 | * here we try to find a cluster of blocks in a block group. The goal | |
575 | * is to find at least bytes free and up to empty_size + bytes free. | |
576 | * We might not find them all in one contiguous area. | |
577 | * | |
578 | * returns zero and sets up cluster if things worked out, otherwise | |
579 | * it returns -enospc | |
580 | */ | |
581 | int btrfs_find_space_cluster(struct btrfs_trans_handle *trans, | |
582 | struct btrfs_block_group_cache *block_group, | |
583 | struct btrfs_free_cluster *cluster, | |
584 | u64 offset, u64 bytes, u64 empty_size) | |
585 | { | |
586 | struct btrfs_free_space *entry = NULL; | |
587 | struct rb_node *node; | |
588 | struct btrfs_free_space *next; | |
589 | struct btrfs_free_space *last; | |
590 | u64 min_bytes; | |
591 | u64 window_start; | |
592 | u64 window_free; | |
593 | u64 max_extent = 0; | |
594 | int total_retries = 0; | |
595 | int ret; | |
596 | ||
597 | /* for metadata, allow allocates with more holes */ | |
598 | if (block_group->flags & BTRFS_BLOCK_GROUP_METADATA) { | |
599 | /* | |
600 | * we want to do larger allocations when we are | |
601 | * flushing out the delayed refs, it helps prevent | |
602 | * making more work as we go along. | |
603 | */ | |
604 | if (trans->transaction->delayed_refs.flushing) | |
605 | min_bytes = max(bytes, (bytes + empty_size) >> 1); | |
606 | else | |
607 | min_bytes = max(bytes, (bytes + empty_size) >> 4); | |
608 | } else | |
609 | min_bytes = max(bytes, (bytes + empty_size) >> 2); | |
610 | ||
611 | spin_lock(&block_group->tree_lock); | |
612 | spin_lock(&cluster->lock); | |
613 | ||
614 | /* someone already found a cluster, hooray */ | |
615 | if (cluster->block_group) { | |
616 | ret = 0; | |
617 | goto out; | |
618 | } | |
619 | again: | |
620 | min_bytes = min(min_bytes, bytes + empty_size); | |
621 | entry = tree_search_bytes(&block_group->free_space_bytes, | |
622 | offset, min_bytes); | |
623 | if (!entry) { | |
624 | ret = -ENOSPC; | |
625 | goto out; | |
626 | } | |
627 | window_start = entry->offset; | |
628 | window_free = entry->bytes; | |
629 | last = entry; | |
630 | max_extent = entry->bytes; | |
631 | ||
632 | while(1) { | |
633 | /* out window is just right, lets fill it */ | |
634 | if (window_free >= bytes + empty_size) | |
635 | break; | |
636 | ||
637 | node = rb_next(&last->offset_index); | |
638 | if (!node) { | |
639 | ret = -ENOSPC; | |
640 | goto out; | |
641 | } | |
642 | next = rb_entry(node, struct btrfs_free_space, offset_index); | |
643 | ||
644 | /* | |
645 | * we haven't filled the empty size and the window is | |
646 | * very large. reset and try again | |
647 | */ | |
648 | if (next->offset - window_start > (bytes + empty_size) * 2) { | |
649 | entry = next; | |
650 | window_start = entry->offset; | |
651 | window_free = entry->bytes; | |
652 | last = entry; | |
653 | max_extent = 0; | |
654 | total_retries++; | |
2c943de6 | 655 | if (total_retries % 64 == 0) { |
fa9c0d79 CM |
656 | if (min_bytes >= (bytes + empty_size)) { |
657 | ret = -ENOSPC; | |
658 | goto out; | |
659 | } | |
660 | /* | |
661 | * grow our allocation a bit, we're not having | |
662 | * much luck | |
663 | */ | |
664 | min_bytes *= 2; | |
665 | goto again; | |
666 | } | |
667 | } else { | |
668 | last = next; | |
669 | window_free += next->bytes; | |
670 | if (entry->bytes > max_extent) | |
671 | max_extent = entry->bytes; | |
672 | } | |
673 | } | |
674 | ||
675 | cluster->window_start = entry->offset; | |
676 | ||
677 | /* | |
678 | * now we've found our entries, pull them out of the free space | |
679 | * cache and put them into the cluster rbtree | |
680 | * | |
681 | * The cluster includes an rbtree, but only uses the offset index | |
682 | * of each free space cache entry. | |
683 | */ | |
684 | while(1) { | |
685 | node = rb_next(&entry->offset_index); | |
686 | unlink_free_space(block_group, entry); | |
687 | ret = tree_insert_offset(&cluster->root, entry->offset, | |
688 | &entry->offset_index); | |
689 | BUG_ON(ret); | |
690 | ||
691 | if (!node || entry == last) | |
692 | break; | |
693 | ||
694 | entry = rb_entry(node, struct btrfs_free_space, offset_index); | |
695 | } | |
696 | ret = 0; | |
697 | cluster->max_size = max_extent; | |
698 | atomic_inc(&block_group->count); | |
699 | list_add_tail(&cluster->block_group_list, &block_group->cluster_list); | |
700 | cluster->block_group = block_group; | |
701 | out: | |
702 | spin_unlock(&cluster->lock); | |
703 | spin_unlock(&block_group->tree_lock); | |
704 | ||
705 | return ret; | |
706 | } | |
707 | ||
708 | /* | |
709 | * simple code to zero out a cluster | |
710 | */ | |
711 | void btrfs_init_free_cluster(struct btrfs_free_cluster *cluster) | |
712 | { | |
713 | spin_lock_init(&cluster->lock); | |
714 | spin_lock_init(&cluster->refill_lock); | |
715 | cluster->root.rb_node = NULL; | |
716 | cluster->max_size = 0; | |
717 | INIT_LIST_HEAD(&cluster->block_group_list); | |
718 | cluster->block_group = NULL; | |
719 | } | |
720 |