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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" | |
21 | ||
22 | static int tree_insert_offset(struct rb_root *root, u64 offset, | |
23 | struct rb_node *node) | |
24 | { | |
25 | struct rb_node **p = &root->rb_node; | |
26 | struct rb_node *parent = NULL; | |
27 | struct btrfs_free_space *info; | |
28 | ||
29 | while (*p) { | |
30 | parent = *p; | |
31 | info = rb_entry(parent, struct btrfs_free_space, offset_index); | |
32 | ||
33 | if (offset < info->offset) | |
34 | p = &(*p)->rb_left; | |
35 | else if (offset > info->offset) | |
36 | p = &(*p)->rb_right; | |
37 | else | |
38 | return -EEXIST; | |
39 | } | |
40 | ||
41 | rb_link_node(node, parent, p); | |
42 | rb_insert_color(node, root); | |
43 | ||
44 | return 0; | |
45 | } | |
46 | ||
47 | static int tree_insert_bytes(struct rb_root *root, u64 bytes, | |
48 | struct rb_node *node) | |
49 | { | |
50 | struct rb_node **p = &root->rb_node; | |
51 | struct rb_node *parent = NULL; | |
52 | struct btrfs_free_space *info; | |
53 | ||
54 | while (*p) { | |
55 | parent = *p; | |
56 | info = rb_entry(parent, struct btrfs_free_space, bytes_index); | |
57 | ||
58 | if (bytes < info->bytes) | |
59 | p = &(*p)->rb_left; | |
60 | else | |
61 | p = &(*p)->rb_right; | |
62 | } | |
63 | ||
64 | rb_link_node(node, parent, p); | |
65 | rb_insert_color(node, root); | |
66 | ||
67 | return 0; | |
68 | } | |
69 | ||
70 | /* | |
70cb0743 JB |
71 | * searches the tree for the given offset. |
72 | * | |
73 | * fuzzy == 1: this is used for allocations where we are given a hint of where | |
74 | * to look for free space. Because the hint may not be completely on an offset | |
75 | * mark, or the hint may no longer point to free space we need to fudge our | |
76 | * results a bit. So we look for free space starting at or after offset with at | |
77 | * least bytes size. We prefer to find as close to the given offset as we can. | |
78 | * Also if the offset is within a free space range, then we will return the free | |
79 | * space that contains the given offset, which means we can return a free space | |
80 | * chunk with an offset before the provided offset. | |
81 | * | |
82 | * fuzzy == 0: this is just a normal tree search. Give us the free space that | |
83 | * starts at the given offset which is at least bytes size, and if its not there | |
84 | * return NULL. | |
0f9dd46c JB |
85 | */ |
86 | static struct btrfs_free_space *tree_search_offset(struct rb_root *root, | |
87 | u64 offset, u64 bytes, | |
70cb0743 | 88 | int fuzzy) |
0f9dd46c JB |
89 | { |
90 | struct rb_node *n = root->rb_node; | |
91 | struct btrfs_free_space *entry, *ret = NULL; | |
92 | ||
93 | while (n) { | |
94 | entry = rb_entry(n, struct btrfs_free_space, offset_index); | |
95 | ||
96 | if (offset < entry->offset) { | |
70cb0743 | 97 | if (fuzzy && |
0f9dd46c JB |
98 | (!ret || entry->offset < ret->offset) && |
99 | (bytes <= entry->bytes)) | |
100 | ret = entry; | |
101 | n = n->rb_left; | |
102 | } else if (offset > entry->offset) { | |
70cb0743 JB |
103 | if (fuzzy && |
104 | (entry->offset + entry->bytes - 1) >= offset && | |
37d3cddd | 105 | bytes <= entry->bytes) { |
0f9dd46c JB |
106 | ret = entry; |
107 | break; | |
108 | } | |
109 | n = n->rb_right; | |
110 | } else { | |
111 | if (bytes > entry->bytes) { | |
112 | n = n->rb_right; | |
113 | continue; | |
114 | } | |
115 | ret = entry; | |
116 | break; | |
117 | } | |
118 | } | |
119 | ||
120 | return ret; | |
121 | } | |
122 | ||
123 | /* | |
124 | * return a chunk at least bytes size, as close to offset that we can get. | |
125 | */ | |
126 | static struct btrfs_free_space *tree_search_bytes(struct rb_root *root, | |
127 | u64 offset, u64 bytes) | |
128 | { | |
129 | struct rb_node *n = root->rb_node; | |
130 | struct btrfs_free_space *entry, *ret = NULL; | |
131 | ||
132 | while (n) { | |
133 | entry = rb_entry(n, struct btrfs_free_space, bytes_index); | |
134 | ||
135 | if (bytes < entry->bytes) { | |
136 | /* | |
137 | * We prefer to get a hole size as close to the size we | |
138 | * are asking for so we don't take small slivers out of | |
139 | * huge holes, but we also want to get as close to the | |
140 | * offset as possible so we don't have a whole lot of | |
141 | * fragmentation. | |
142 | */ | |
143 | if (offset <= entry->offset) { | |
144 | if (!ret) | |
145 | ret = entry; | |
146 | else if (entry->bytes < ret->bytes) | |
147 | ret = entry; | |
148 | else if (entry->offset < ret->offset) | |
149 | ret = entry; | |
150 | } | |
151 | n = n->rb_left; | |
152 | } else if (bytes > entry->bytes) { | |
153 | n = n->rb_right; | |
154 | } else { | |
155 | /* | |
156 | * Ok we may have multiple chunks of the wanted size, | |
157 | * so we don't want to take the first one we find, we | |
158 | * want to take the one closest to our given offset, so | |
159 | * keep searching just in case theres a better match. | |
160 | */ | |
161 | n = n->rb_right; | |
162 | if (offset > entry->offset) | |
163 | continue; | |
164 | else if (!ret || entry->offset < ret->offset) | |
165 | ret = entry; | |
166 | } | |
167 | } | |
168 | ||
169 | return ret; | |
170 | } | |
171 | ||
172 | static void unlink_free_space(struct btrfs_block_group_cache *block_group, | |
173 | struct btrfs_free_space *info) | |
174 | { | |
175 | rb_erase(&info->offset_index, &block_group->free_space_offset); | |
176 | rb_erase(&info->bytes_index, &block_group->free_space_bytes); | |
177 | } | |
178 | ||
179 | static int link_free_space(struct btrfs_block_group_cache *block_group, | |
180 | struct btrfs_free_space *info) | |
181 | { | |
182 | int ret = 0; | |
183 | ||
184 | ||
185 | ret = tree_insert_offset(&block_group->free_space_offset, info->offset, | |
186 | &info->offset_index); | |
187 | if (ret) | |
188 | return ret; | |
189 | ||
190 | ret = tree_insert_bytes(&block_group->free_space_bytes, info->bytes, | |
191 | &info->bytes_index); | |
192 | if (ret) | |
193 | return ret; | |
194 | ||
195 | return ret; | |
196 | } | |
197 | ||
25179201 JB |
198 | static int __btrfs_add_free_space(struct btrfs_block_group_cache *block_group, |
199 | u64 offset, u64 bytes) | |
0f9dd46c JB |
200 | { |
201 | struct btrfs_free_space *right_info; | |
202 | struct btrfs_free_space *left_info; | |
203 | struct btrfs_free_space *info = NULL; | |
0f9dd46c JB |
204 | int ret = 0; |
205 | ||
0f9dd46c JB |
206 | /* |
207 | * first we want to see if there is free space adjacent to the range we | |
208 | * are adding, if there is remove that struct and add a new one to | |
209 | * cover the entire range | |
210 | */ | |
0f9dd46c | 211 | right_info = tree_search_offset(&block_group->free_space_offset, |
70cb0743 | 212 | offset+bytes, 0, 0); |
0f9dd46c JB |
213 | left_info = tree_search_offset(&block_group->free_space_offset, |
214 | offset-1, 0, 1); | |
215 | ||
70cb0743 | 216 | if (right_info) { |
0f9dd46c JB |
217 | unlink_free_space(block_group, right_info); |
218 | info = right_info; | |
219 | info->offset = offset; | |
220 | info->bytes += bytes; | |
0f9dd46c JB |
221 | } |
222 | ||
70cb0743 | 223 | if (left_info && left_info->offset + left_info->bytes == offset) { |
0f9dd46c JB |
224 | unlink_free_space(block_group, left_info); |
225 | ||
0f9dd46c JB |
226 | if (info) { |
227 | info->offset = left_info->offset; | |
228 | info->bytes += left_info->bytes; | |
229 | kfree(left_info); | |
230 | } else { | |
231 | info = left_info; | |
232 | info->bytes += bytes; | |
233 | } | |
234 | } | |
235 | ||
236 | if (info) { | |
237 | ret = link_free_space(block_group, info); | |
70cb0743 JB |
238 | if (ret) |
239 | kfree(info); | |
0f9dd46c JB |
240 | goto out; |
241 | } | |
242 | ||
70cb0743 JB |
243 | info = kzalloc(sizeof(struct btrfs_free_space), GFP_NOFS); |
244 | if (!info) | |
245 | return -ENOMEM; | |
246 | ||
0f9dd46c JB |
247 | info->offset = offset; |
248 | info->bytes = bytes; | |
249 | ||
250 | ret = link_free_space(block_group, info); | |
251 | if (ret) | |
252 | kfree(info); | |
253 | out: | |
0f9dd46c JB |
254 | if (ret) { |
255 | printk(KERN_ERR "btrfs: unable to add free space :%d\n", ret); | |
256 | if (ret == -EEXIST) | |
257 | BUG(); | |
258 | } | |
259 | ||
0f9dd46c JB |
260 | return ret; |
261 | } | |
262 | ||
25179201 JB |
263 | static int |
264 | __btrfs_remove_free_space(struct btrfs_block_group_cache *block_group, | |
265 | u64 offset, u64 bytes) | |
0f9dd46c JB |
266 | { |
267 | struct btrfs_free_space *info; | |
268 | int ret = 0; | |
269 | ||
70cb0743 | 270 | BUG_ON(!block_group->cached); |
0f9dd46c JB |
271 | info = tree_search_offset(&block_group->free_space_offset, offset, 0, |
272 | 1); | |
273 | ||
274 | if (info && info->offset == offset) { | |
275 | if (info->bytes < bytes) { | |
d397712b CM |
276 | printk(KERN_ERR "Found free space at %llu, size %llu," |
277 | "trying to use %llu\n", | |
278 | (unsigned long long)info->offset, | |
279 | (unsigned long long)info->bytes, | |
280 | (unsigned long long)bytes); | |
0f9dd46c JB |
281 | WARN_ON(1); |
282 | ret = -EINVAL; | |
283 | goto out; | |
284 | } | |
0f9dd46c JB |
285 | unlink_free_space(block_group, info); |
286 | ||
287 | if (info->bytes == bytes) { | |
288 | kfree(info); | |
289 | goto out; | |
290 | } | |
291 | ||
292 | info->offset += bytes; | |
293 | info->bytes -= bytes; | |
294 | ||
295 | ret = link_free_space(block_group, info); | |
296 | BUG_ON(ret); | |
9b49c9b9 CM |
297 | } else if (info && info->offset < offset && |
298 | info->offset + info->bytes >= offset + bytes) { | |
299 | u64 old_start = info->offset; | |
300 | /* | |
301 | * we're freeing space in the middle of the info, | |
302 | * this can happen during tree log replay | |
303 | * | |
304 | * first unlink the old info and then | |
305 | * insert it again after the hole we're creating | |
306 | */ | |
307 | unlink_free_space(block_group, info); | |
308 | if (offset + bytes < info->offset + info->bytes) { | |
309 | u64 old_end = info->offset + info->bytes; | |
310 | ||
311 | info->offset = offset + bytes; | |
312 | info->bytes = old_end - info->offset; | |
313 | ret = link_free_space(block_group, info); | |
314 | BUG_ON(ret); | |
315 | } else { | |
316 | /* the hole we're creating ends at the end | |
317 | * of the info struct, just free the info | |
318 | */ | |
319 | kfree(info); | |
320 | } | |
321 | ||
322 | /* step two, insert a new info struct to cover anything | |
323 | * before the hole | |
324 | */ | |
25179201 JB |
325 | ret = __btrfs_add_free_space(block_group, old_start, |
326 | offset - old_start); | |
9b49c9b9 | 327 | BUG_ON(ret); |
0f9dd46c | 328 | } else { |
70cb0743 JB |
329 | if (!info) { |
330 | printk(KERN_ERR "couldn't find space %llu to free\n", | |
331 | (unsigned long long)offset); | |
332 | printk(KERN_ERR "cached is %d, offset %llu bytes %llu\n", | |
333 | block_group->cached, block_group->key.objectid, | |
334 | block_group->key.offset); | |
335 | btrfs_dump_free_space(block_group, bytes); | |
336 | } else if (info) { | |
337 | printk(KERN_ERR "hmm, found offset=%llu bytes=%llu, " | |
338 | "but wanted offset=%llu bytes=%llu\n", | |
339 | info->offset, info->bytes, offset, bytes); | |
340 | } | |
0f9dd46c JB |
341 | WARN_ON(1); |
342 | } | |
343 | out: | |
25179201 JB |
344 | return ret; |
345 | } | |
346 | ||
347 | int btrfs_add_free_space(struct btrfs_block_group_cache *block_group, | |
348 | u64 offset, u64 bytes) | |
349 | { | |
350 | int ret; | |
25179201 JB |
351 | |
352 | mutex_lock(&block_group->alloc_mutex); | |
353 | ret = __btrfs_add_free_space(block_group, offset, bytes); | |
25179201 JB |
354 | mutex_unlock(&block_group->alloc_mutex); |
355 | ||
356 | return ret; | |
357 | } | |
358 | ||
359 | int btrfs_add_free_space_lock(struct btrfs_block_group_cache *block_group, | |
360 | u64 offset, u64 bytes) | |
361 | { | |
362 | int ret; | |
25179201 JB |
363 | |
364 | ret = __btrfs_add_free_space(block_group, offset, bytes); | |
25179201 JB |
365 | |
366 | return ret; | |
367 | } | |
368 | ||
369 | int btrfs_remove_free_space(struct btrfs_block_group_cache *block_group, | |
370 | u64 offset, u64 bytes) | |
371 | { | |
372 | int ret = 0; | |
373 | ||
374 | mutex_lock(&block_group->alloc_mutex); | |
375 | ret = __btrfs_remove_free_space(block_group, offset, bytes); | |
376 | mutex_unlock(&block_group->alloc_mutex); | |
377 | ||
378 | return ret; | |
379 | } | |
380 | ||
381 | int btrfs_remove_free_space_lock(struct btrfs_block_group_cache *block_group, | |
382 | u64 offset, u64 bytes) | |
383 | { | |
384 | int ret; | |
385 | ||
386 | ret = __btrfs_remove_free_space(block_group, offset, bytes); | |
387 | ||
0f9dd46c JB |
388 | return ret; |
389 | } | |
390 | ||
391 | void btrfs_dump_free_space(struct btrfs_block_group_cache *block_group, | |
392 | u64 bytes) | |
393 | { | |
394 | struct btrfs_free_space *info; | |
395 | struct rb_node *n; | |
396 | int count = 0; | |
397 | ||
398 | for (n = rb_first(&block_group->free_space_offset); n; n = rb_next(n)) { | |
399 | info = rb_entry(n, struct btrfs_free_space, offset_index); | |
400 | if (info->bytes >= bytes) | |
401 | count++; | |
70cb0743 JB |
402 | printk(KERN_ERR "entry offset %llu, bytes %llu\n", info->offset, |
403 | info->bytes); | |
0f9dd46c JB |
404 | } |
405 | printk(KERN_INFO "%d blocks of free space at or bigger than bytes is" | |
406 | "\n", count); | |
407 | } | |
408 | ||
409 | u64 btrfs_block_group_free_space(struct btrfs_block_group_cache *block_group) | |
410 | { | |
411 | struct btrfs_free_space *info; | |
412 | struct rb_node *n; | |
413 | u64 ret = 0; | |
414 | ||
415 | for (n = rb_first(&block_group->free_space_offset); n; | |
416 | n = rb_next(n)) { | |
417 | info = rb_entry(n, struct btrfs_free_space, offset_index); | |
418 | ret += info->bytes; | |
419 | } | |
420 | ||
421 | return ret; | |
422 | } | |
423 | ||
424 | void btrfs_remove_free_space_cache(struct btrfs_block_group_cache *block_group) | |
425 | { | |
426 | struct btrfs_free_space *info; | |
427 | struct rb_node *node; | |
428 | ||
25179201 | 429 | mutex_lock(&block_group->alloc_mutex); |
0f9dd46c JB |
430 | while ((node = rb_last(&block_group->free_space_bytes)) != NULL) { |
431 | info = rb_entry(node, struct btrfs_free_space, bytes_index); | |
432 | unlink_free_space(block_group, info); | |
433 | kfree(info); | |
434 | if (need_resched()) { | |
25179201 | 435 | mutex_unlock(&block_group->alloc_mutex); |
0f9dd46c | 436 | cond_resched(); |
25179201 | 437 | mutex_lock(&block_group->alloc_mutex); |
0f9dd46c JB |
438 | } |
439 | } | |
25179201 | 440 | mutex_unlock(&block_group->alloc_mutex); |
0f9dd46c JB |
441 | } |
442 | ||
b2950863 CH |
443 | #if 0 |
444 | static struct btrfs_free_space *btrfs_find_free_space_offset(struct | |
0f9dd46c JB |
445 | btrfs_block_group_cache |
446 | *block_group, u64 offset, | |
447 | u64 bytes) | |
448 | { | |
449 | struct btrfs_free_space *ret; | |
450 | ||
25179201 | 451 | mutex_lock(&block_group->alloc_mutex); |
0f9dd46c JB |
452 | ret = tree_search_offset(&block_group->free_space_offset, offset, |
453 | bytes, 0); | |
25179201 | 454 | mutex_unlock(&block_group->alloc_mutex); |
0f9dd46c JB |
455 | |
456 | return ret; | |
457 | } | |
458 | ||
b2950863 | 459 | static struct btrfs_free_space *btrfs_find_free_space_bytes(struct |
0f9dd46c JB |
460 | btrfs_block_group_cache |
461 | *block_group, u64 offset, | |
462 | u64 bytes) | |
463 | { | |
464 | struct btrfs_free_space *ret; | |
465 | ||
25179201 | 466 | mutex_lock(&block_group->alloc_mutex); |
0f9dd46c JB |
467 | |
468 | ret = tree_search_bytes(&block_group->free_space_bytes, offset, bytes); | |
25179201 | 469 | mutex_unlock(&block_group->alloc_mutex); |
0f9dd46c JB |
470 | |
471 | return ret; | |
472 | } | |
b2950863 | 473 | #endif |
0f9dd46c JB |
474 | |
475 | struct btrfs_free_space *btrfs_find_free_space(struct btrfs_block_group_cache | |
476 | *block_group, u64 offset, | |
477 | u64 bytes) | |
478 | { | |
25179201 | 479 | struct btrfs_free_space *ret = NULL; |
0f9dd46c | 480 | |
0f9dd46c | 481 | ret = tree_search_offset(&block_group->free_space_offset, offset, |
70cb0743 | 482 | bytes, 1); |
0f9dd46c JB |
483 | if (!ret) |
484 | ret = tree_search_bytes(&block_group->free_space_bytes, | |
485 | offset, bytes); | |
486 | ||
0f9dd46c JB |
487 | return ret; |
488 | } |