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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 | /* | |
71 | * searches the tree for the given offset. If contains is set we will return | |
72 | * the free space that contains the given offset. If contains is not set we | |
73 | * will return the free space that starts at or after the given offset and is | |
74 | * at least bytes long. | |
75 | */ | |
76 | static struct btrfs_free_space *tree_search_offset(struct rb_root *root, | |
77 | u64 offset, u64 bytes, | |
78 | int contains) | |
79 | { | |
80 | struct rb_node *n = root->rb_node; | |
81 | struct btrfs_free_space *entry, *ret = NULL; | |
82 | ||
83 | while (n) { | |
84 | entry = rb_entry(n, struct btrfs_free_space, offset_index); | |
85 | ||
86 | if (offset < entry->offset) { | |
87 | if (!contains && | |
88 | (!ret || entry->offset < ret->offset) && | |
89 | (bytes <= entry->bytes)) | |
90 | ret = entry; | |
91 | n = n->rb_left; | |
92 | } else if (offset > entry->offset) { | |
93 | if (contains && | |
94 | (entry->offset + entry->bytes - 1) >= offset) { | |
95 | ret = entry; | |
96 | break; | |
97 | } | |
98 | n = n->rb_right; | |
99 | } else { | |
100 | if (bytes > entry->bytes) { | |
101 | n = n->rb_right; | |
102 | continue; | |
103 | } | |
104 | ret = entry; | |
105 | break; | |
106 | } | |
107 | } | |
108 | ||
109 | return ret; | |
110 | } | |
111 | ||
112 | /* | |
113 | * return a chunk at least bytes size, as close to offset that we can get. | |
114 | */ | |
115 | static struct btrfs_free_space *tree_search_bytes(struct rb_root *root, | |
116 | u64 offset, u64 bytes) | |
117 | { | |
118 | struct rb_node *n = root->rb_node; | |
119 | struct btrfs_free_space *entry, *ret = NULL; | |
120 | ||
121 | while (n) { | |
122 | entry = rb_entry(n, struct btrfs_free_space, bytes_index); | |
123 | ||
124 | if (bytes < entry->bytes) { | |
125 | /* | |
126 | * We prefer to get a hole size as close to the size we | |
127 | * are asking for so we don't take small slivers out of | |
128 | * huge holes, but we also want to get as close to the | |
129 | * offset as possible so we don't have a whole lot of | |
130 | * fragmentation. | |
131 | */ | |
132 | if (offset <= entry->offset) { | |
133 | if (!ret) | |
134 | ret = entry; | |
135 | else if (entry->bytes < ret->bytes) | |
136 | ret = entry; | |
137 | else if (entry->offset < ret->offset) | |
138 | ret = entry; | |
139 | } | |
140 | n = n->rb_left; | |
141 | } else if (bytes > entry->bytes) { | |
142 | n = n->rb_right; | |
143 | } else { | |
144 | /* | |
145 | * Ok we may have multiple chunks of the wanted size, | |
146 | * so we don't want to take the first one we find, we | |
147 | * want to take the one closest to our given offset, so | |
148 | * keep searching just in case theres a better match. | |
149 | */ | |
150 | n = n->rb_right; | |
151 | if (offset > entry->offset) | |
152 | continue; | |
153 | else if (!ret || entry->offset < ret->offset) | |
154 | ret = entry; | |
155 | } | |
156 | } | |
157 | ||
158 | return ret; | |
159 | } | |
160 | ||
161 | static void unlink_free_space(struct btrfs_block_group_cache *block_group, | |
162 | struct btrfs_free_space *info) | |
163 | { | |
164 | rb_erase(&info->offset_index, &block_group->free_space_offset); | |
165 | rb_erase(&info->bytes_index, &block_group->free_space_bytes); | |
166 | } | |
167 | ||
168 | static int link_free_space(struct btrfs_block_group_cache *block_group, | |
169 | struct btrfs_free_space *info) | |
170 | { | |
171 | int ret = 0; | |
172 | ||
173 | ||
174 | ret = tree_insert_offset(&block_group->free_space_offset, info->offset, | |
175 | &info->offset_index); | |
176 | if (ret) | |
177 | return ret; | |
178 | ||
179 | ret = tree_insert_bytes(&block_group->free_space_bytes, info->bytes, | |
180 | &info->bytes_index); | |
181 | if (ret) | |
182 | return ret; | |
183 | ||
184 | return ret; | |
185 | } | |
186 | ||
187 | int btrfs_add_free_space(struct btrfs_block_group_cache *block_group, | |
188 | u64 offset, u64 bytes) | |
189 | { | |
190 | struct btrfs_free_space *right_info; | |
191 | struct btrfs_free_space *left_info; | |
192 | struct btrfs_free_space *info = NULL; | |
193 | struct btrfs_free_space *alloc_info; | |
194 | int ret = 0; | |
195 | ||
196 | alloc_info = kzalloc(sizeof(struct btrfs_free_space), GFP_NOFS); | |
197 | if (!alloc_info) | |
198 | return -ENOMEM; | |
199 | ||
200 | /* | |
201 | * first we want to see if there is free space adjacent to the range we | |
202 | * are adding, if there is remove that struct and add a new one to | |
203 | * cover the entire range | |
204 | */ | |
205 | spin_lock(&block_group->lock); | |
206 | ||
207 | right_info = tree_search_offset(&block_group->free_space_offset, | |
208 | offset+bytes, 0, 1); | |
209 | left_info = tree_search_offset(&block_group->free_space_offset, | |
210 | offset-1, 0, 1); | |
211 | ||
212 | if (right_info && right_info->offset == offset+bytes) { | |
213 | unlink_free_space(block_group, right_info); | |
214 | info = right_info; | |
215 | info->offset = offset; | |
216 | info->bytes += bytes; | |
217 | } else if (right_info && right_info->offset != offset+bytes) { | |
218 | printk(KERN_ERR "adding space in the middle of an existing " | |
219 | "free space area. existing: offset=%Lu, bytes=%Lu. " | |
220 | "new: offset=%Lu, bytes=%Lu\n", right_info->offset, | |
221 | right_info->bytes, offset, bytes); | |
222 | BUG(); | |
223 | } | |
224 | ||
225 | if (left_info) { | |
226 | unlink_free_space(block_group, left_info); | |
227 | ||
228 | if (unlikely((left_info->offset + left_info->bytes) != | |
229 | offset)) { | |
230 | printk(KERN_ERR "free space to the left of new free " | |
231 | "space isn't quite right. existing: offset=%Lu," | |
232 | " bytes=%Lu. new: offset=%Lu, bytes=%Lu\n", | |
233 | left_info->offset, left_info->bytes, offset, | |
234 | bytes); | |
235 | BUG(); | |
236 | } | |
237 | ||
238 | if (info) { | |
239 | info->offset = left_info->offset; | |
240 | info->bytes += left_info->bytes; | |
241 | kfree(left_info); | |
242 | } else { | |
243 | info = left_info; | |
244 | info->bytes += bytes; | |
245 | } | |
246 | } | |
247 | ||
248 | if (info) { | |
249 | ret = link_free_space(block_group, info); | |
250 | if (!ret) | |
251 | info = NULL; | |
252 | goto out; | |
253 | } | |
254 | ||
255 | info = alloc_info; | |
256 | alloc_info = NULL; | |
257 | info->offset = offset; | |
258 | info->bytes = bytes; | |
259 | ||
260 | ret = link_free_space(block_group, info); | |
261 | if (ret) | |
262 | kfree(info); | |
263 | out: | |
264 | spin_unlock(&block_group->lock); | |
265 | if (ret) { | |
266 | printk(KERN_ERR "btrfs: unable to add free space :%d\n", ret); | |
267 | if (ret == -EEXIST) | |
268 | BUG(); | |
269 | } | |
270 | ||
271 | if (alloc_info) | |
272 | kfree(alloc_info); | |
273 | ||
274 | return ret; | |
275 | } | |
276 | ||
277 | int btrfs_remove_free_space(struct btrfs_block_group_cache *block_group, | |
278 | u64 offset, u64 bytes) | |
279 | { | |
280 | struct btrfs_free_space *info; | |
281 | int ret = 0; | |
282 | ||
283 | spin_lock(&block_group->lock); | |
284 | info = tree_search_offset(&block_group->free_space_offset, offset, 0, | |
285 | 1); | |
286 | ||
287 | if (info && info->offset == offset) { | |
288 | if (info->bytes < bytes) { | |
289 | printk(KERN_ERR "Found free space at %Lu, size %Lu," | |
290 | "trying to use %Lu\n", | |
291 | info->offset, info->bytes, bytes); | |
292 | WARN_ON(1); | |
293 | ret = -EINVAL; | |
294 | goto out; | |
295 | } | |
296 | ||
297 | unlink_free_space(block_group, info); | |
298 | ||
299 | if (info->bytes == bytes) { | |
300 | kfree(info); | |
301 | goto out; | |
302 | } | |
303 | ||
304 | info->offset += bytes; | |
305 | info->bytes -= bytes; | |
306 | ||
307 | ret = link_free_space(block_group, info); | |
308 | BUG_ON(ret); | |
309 | } else { | |
310 | WARN_ON(1); | |
311 | } | |
312 | out: | |
313 | spin_unlock(&block_group->lock); | |
314 | return ret; | |
315 | } | |
316 | ||
317 | void btrfs_dump_free_space(struct btrfs_block_group_cache *block_group, | |
318 | u64 bytes) | |
319 | { | |
320 | struct btrfs_free_space *info; | |
321 | struct rb_node *n; | |
322 | int count = 0; | |
323 | ||
324 | for (n = rb_first(&block_group->free_space_offset); n; n = rb_next(n)) { | |
325 | info = rb_entry(n, struct btrfs_free_space, offset_index); | |
326 | if (info->bytes >= bytes) | |
327 | count++; | |
328 | //printk(KERN_INFO "offset=%Lu, bytes=%Lu\n", info->offset, | |
329 | // info->bytes); | |
330 | } | |
331 | printk(KERN_INFO "%d blocks of free space at or bigger than bytes is" | |
332 | "\n", count); | |
333 | } | |
334 | ||
335 | u64 btrfs_block_group_free_space(struct btrfs_block_group_cache *block_group) | |
336 | { | |
337 | struct btrfs_free_space *info; | |
338 | struct rb_node *n; | |
339 | u64 ret = 0; | |
340 | ||
341 | for (n = rb_first(&block_group->free_space_offset); n; | |
342 | n = rb_next(n)) { | |
343 | info = rb_entry(n, struct btrfs_free_space, offset_index); | |
344 | ret += info->bytes; | |
345 | } | |
346 | ||
347 | return ret; | |
348 | } | |
349 | ||
350 | void btrfs_remove_free_space_cache(struct btrfs_block_group_cache *block_group) | |
351 | { | |
352 | struct btrfs_free_space *info; | |
353 | struct rb_node *node; | |
354 | ||
355 | spin_lock(&block_group->lock); | |
356 | while ((node = rb_last(&block_group->free_space_bytes)) != NULL) { | |
357 | info = rb_entry(node, struct btrfs_free_space, bytes_index); | |
358 | unlink_free_space(block_group, info); | |
359 | kfree(info); | |
360 | if (need_resched()) { | |
361 | spin_unlock(&block_group->lock); | |
362 | cond_resched(); | |
363 | spin_lock(&block_group->lock); | |
364 | } | |
365 | } | |
366 | spin_unlock(&block_group->lock); | |
367 | } | |
368 | ||
369 | struct btrfs_free_space *btrfs_find_free_space_offset(struct | |
370 | btrfs_block_group_cache | |
371 | *block_group, u64 offset, | |
372 | u64 bytes) | |
373 | { | |
374 | struct btrfs_free_space *ret; | |
375 | ||
376 | spin_lock(&block_group->lock); | |
377 | ret = tree_search_offset(&block_group->free_space_offset, offset, | |
378 | bytes, 0); | |
379 | spin_unlock(&block_group->lock); | |
380 | ||
381 | return ret; | |
382 | } | |
383 | ||
384 | struct btrfs_free_space *btrfs_find_free_space_bytes(struct | |
385 | btrfs_block_group_cache | |
386 | *block_group, u64 offset, | |
387 | u64 bytes) | |
388 | { | |
389 | struct btrfs_free_space *ret; | |
390 | ||
391 | spin_lock(&block_group->lock); | |
392 | ||
393 | ret = tree_search_bytes(&block_group->free_space_bytes, offset, bytes); | |
394 | spin_unlock(&block_group->lock); | |
395 | ||
396 | return ret; | |
397 | } | |
398 | ||
399 | struct btrfs_free_space *btrfs_find_free_space(struct btrfs_block_group_cache | |
400 | *block_group, u64 offset, | |
401 | u64 bytes) | |
402 | { | |
403 | struct btrfs_free_space *ret; | |
404 | ||
405 | spin_lock(&block_group->lock); | |
406 | ret = tree_search_offset(&block_group->free_space_offset, offset, | |
407 | bytes, 0); | |
408 | if (!ret) | |
409 | ret = tree_search_bytes(&block_group->free_space_bytes, | |
410 | offset, bytes); | |
411 | ||
412 | spin_unlock(&block_group->lock); | |
413 | ||
414 | return ret; | |
415 | } |