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Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input
[linux-btrfs-devel.git] / fs / btrfs / free-space-cache.c
blob41ac927401d06bc14a2214e245d1cdfbb2d7b603
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/pagemap.h>
20 #include <linux/sched.h>
21 #include <linux/slab.h>
22 #include <linux/math64.h>
23 #include "ctree.h"
24 #include "free-space-cache.h"
25 #include "transaction.h"
26 #include "disk-io.h"
27 #include "extent_io.h"
28 #include "inode-map.h"
29
30 #define BITS_PER_BITMAP (PAGE_CACHE_SIZE * 8)
31 #define MAX_CACHE_BYTES_PER_GIG (32 * 1024)
32
33 static int link_free_space(struct btrfs_free_space_ctl *ctl,
34 struct btrfs_free_space *info);
35
36 static struct inode *__lookup_free_space_inode(struct btrfs_root *root,
37 struct btrfs_path *path,
38 u64 offset)
39 {
40 struct btrfs_key key;
41 struct btrfs_key location;
42 struct btrfs_disk_key disk_key;
43 struct btrfs_free_space_header *header;
44 struct extent_buffer *leaf;
45 struct inode *inode = NULL;
46 int ret;
47
48 key.objectid = BTRFS_FREE_SPACE_OBJECTID;
49 key.offset = offset;
50 key.type = 0;
51
52 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
53 if (ret < 0)
54 return ERR_PTR(ret);
55 if (ret > 0) {
56 btrfs_release_path(path);
57 return ERR_PTR(-ENOENT);
58 }
59
60 leaf = path->nodes[0];
61 header = btrfs_item_ptr(leaf, path->slots[0],
62 struct btrfs_free_space_header);
63 btrfs_free_space_key(leaf, header, &disk_key);
64 btrfs_disk_key_to_cpu(&location, &disk_key);
65 btrfs_release_path(path);
66
67 inode = btrfs_iget(root->fs_info->sb, &location, root, NULL);
68 if (!inode)
69 return ERR_PTR(-ENOENT);
70 if (IS_ERR(inode))
71 return inode;
72 if (is_bad_inode(inode)) {
73 iput(inode);
74 return ERR_PTR(-ENOENT);
75 }
76
77 inode->i_mapping->flags &= ~__GFP_FS;
78
79 return inode;
80 }
81
82 struct inode *lookup_free_space_inode(struct btrfs_root *root,
83 struct btrfs_block_group_cache
84 *block_group, struct btrfs_path *path)
85 {
86 struct inode *inode = NULL;
87
88 spin_lock(&block_group->lock);
89 if (block_group->inode)
90 inode = igrab(block_group->inode);
91 spin_unlock(&block_group->lock);
92 if (inode)
93 return inode;
94
95 inode = __lookup_free_space_inode(root, path,
96 block_group->key.objectid);
97 if (IS_ERR(inode))
98 return inode;
99
100 spin_lock(&block_group->lock);
101 if (BTRFS_I(inode)->flags & BTRFS_INODE_NODATASUM) {
102 printk(KERN_INFO "Old style space inode found, converting.\n");
103 BTRFS_I(inode)->flags &= ~BTRFS_INODE_NODATASUM;
104 block_group->disk_cache_state = BTRFS_DC_CLEAR;
105 }
106
107 if (!btrfs_fs_closing(root->fs_info)) {
108 block_group->inode = igrab(inode);
109 block_group->iref = 1;
110 }
111 spin_unlock(&block_group->lock);
112
113 return inode;
114 }
115
116 int __create_free_space_inode(struct btrfs_root *root,
117 struct btrfs_trans_handle *trans,
118 struct btrfs_path *path, u64 ino, u64 offset)
119 {
120 struct btrfs_key key;
121 struct btrfs_disk_key disk_key;
122 struct btrfs_free_space_header *header;
123 struct btrfs_inode_item *inode_item;
124 struct extent_buffer *leaf;
125 int ret;
126
127 ret = btrfs_insert_empty_inode(trans, root, path, ino);
128 if (ret)
129 return ret;
130
131 leaf = path->nodes[0];
132 inode_item = btrfs_item_ptr(leaf, path->slots[0],
133 struct btrfs_inode_item);
134 btrfs_item_key(leaf, &disk_key, path->slots[0]);
135 memset_extent_buffer(leaf, 0, (unsigned long)inode_item,
136 sizeof(*inode_item));
137 btrfs_set_inode_generation(leaf, inode_item, trans->transid);
138 btrfs_set_inode_size(leaf, inode_item, 0);
139 btrfs_set_inode_nbytes(leaf, inode_item, 0);
140 btrfs_set_inode_uid(leaf, inode_item, 0);
141 btrfs_set_inode_gid(leaf, inode_item, 0);
142 btrfs_set_inode_mode(leaf, inode_item, S_IFREG | 0600);
143 btrfs_set_inode_flags(leaf, inode_item, BTRFS_INODE_NOCOMPRESS |
144 BTRFS_INODE_PREALLOC);
145 btrfs_set_inode_nlink(leaf, inode_item, 1);
146 btrfs_set_inode_transid(leaf, inode_item, trans->transid);
147 btrfs_set_inode_block_group(leaf, inode_item, offset);
148 btrfs_mark_buffer_dirty(leaf);
149 btrfs_release_path(path);
150
151 key.objectid = BTRFS_FREE_SPACE_OBJECTID;
152 key.offset = offset;
153 key.type = 0;
154
155 ret = btrfs_insert_empty_item(trans, root, path, &key,
156 sizeof(struct btrfs_free_space_header));
157 if (ret < 0) {
158 btrfs_release_path(path);
159 return ret;
160 }
161 leaf = path->nodes[0];
162 header = btrfs_item_ptr(leaf, path->slots[0],
163 struct btrfs_free_space_header);
164 memset_extent_buffer(leaf, 0, (unsigned long)header, sizeof(*header));
165 btrfs_set_free_space_key(leaf, header, &disk_key);
166 btrfs_mark_buffer_dirty(leaf);
167 btrfs_release_path(path);
168
169 return 0;
170 }
171
172 int create_free_space_inode(struct btrfs_root *root,
173 struct btrfs_trans_handle *trans,
174 struct btrfs_block_group_cache *block_group,
175 struct btrfs_path *path)
176 {
177 int ret;
178 u64 ino;
179
180 ret = btrfs_find_free_objectid(root, &ino);
181 if (ret < 0)
182 return ret;
183
184 return __create_free_space_inode(root, trans, path, ino,
185 block_group->key.objectid);
186 }
187
188 int btrfs_truncate_free_space_cache(struct btrfs_root *root,
189 struct btrfs_trans_handle *trans,
190 struct btrfs_path *path,
191 struct inode *inode)
192 {
193 struct btrfs_block_rsv *rsv;
194 loff_t oldsize;
195 int ret = 0;
196
197 rsv = trans->block_rsv;
198 trans->block_rsv = root->orphan_block_rsv;
199 ret = btrfs_block_rsv_check(trans, root,
200 root->orphan_block_rsv,
201 0, 5);
202 if (ret)
203 return ret;
204
205 oldsize = i_size_read(inode);
206 btrfs_i_size_write(inode, 0);
207 truncate_pagecache(inode, oldsize, 0);
208
209 /*
210 * We don't need an orphan item because truncating the free space cache
211 * will never be split across transactions.
212 */
213 ret = btrfs_truncate_inode_items(trans, root, inode,
214 0, BTRFS_EXTENT_DATA_KEY);
215
216 trans->block_rsv = rsv;
217 if (ret) {
218 WARN_ON(1);
219 return ret;
220 }
221
222 ret = btrfs_update_inode(trans, root, inode);
223 return ret;
224 }
225
226 static int readahead_cache(struct inode *inode)
227 {
228 struct file_ra_state *ra;
229 unsigned long last_index;
230
231 ra = kzalloc(sizeof(*ra), GFP_NOFS);
232 if (!ra)
233 return -ENOMEM;
234
235 file_ra_state_init(ra, inode->i_mapping);
236 last_index = (i_size_read(inode) - 1) >> PAGE_CACHE_SHIFT;
237
238 page_cache_sync_readahead(inode->i_mapping, ra, NULL, 0, last_index);
239
240 kfree(ra);
241
242 return 0;
243 }
244
245 int __load_free_space_cache(struct btrfs_root *root, struct inode *inode,
246 struct btrfs_free_space_ctl *ctl,
247 struct btrfs_path *path, u64 offset)
248 {
249 struct btrfs_free_space_header *header;
250 struct extent_buffer *leaf;
251 struct page *page;
252 struct btrfs_key key;
253 struct list_head bitmaps;
254 u64 num_entries;
255 u64 num_bitmaps;
256 u64 generation;
257 pgoff_t index = 0;
258 int ret = 0;
259
260 INIT_LIST_HEAD(&bitmaps);
261
262 /* Nothing in the space cache, goodbye */
263 if (!i_size_read(inode))
264 goto out;
265
266 key.objectid = BTRFS_FREE_SPACE_OBJECTID;
267 key.offset = offset;
268 key.type = 0;
269
270 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
271 if (ret < 0)
272 goto out;
273 else if (ret > 0) {
274 btrfs_release_path(path);
275 ret = 0;
276 goto out;
277 }
278
279 ret = -1;
280
281 leaf = path->nodes[0];
282 header = btrfs_item_ptr(leaf, path->slots[0],
283 struct btrfs_free_space_header);
284 num_entries = btrfs_free_space_entries(leaf, header);
285 num_bitmaps = btrfs_free_space_bitmaps(leaf, header);
286 generation = btrfs_free_space_generation(leaf, header);
287 btrfs_release_path(path);
288
289 if (BTRFS_I(inode)->generation != generation) {
290 printk(KERN_ERR "btrfs: free space inode generation (%llu) did"
291 " not match free space cache generation (%llu)\n",
292 (unsigned long long)BTRFS_I(inode)->generation,
293 (unsigned long long)generation);
294 goto out;
295 }
296
297 if (!num_entries)
298 goto out;
299
300 ret = readahead_cache(inode);
301 if (ret)
302 goto out;
303
304 while (1) {
305 struct btrfs_free_space_entry *entry;
306 struct btrfs_free_space *e;
307 void *addr;
308 unsigned long offset = 0;
309 int need_loop = 0;
310
311 if (!num_entries && !num_bitmaps)
312 break;
313
314 page = find_or_create_page(inode->i_mapping, index, GFP_NOFS);
315 if (!page)
316 goto free_cache;
317
318 if (!PageUptodate(page)) {
319 btrfs_readpage(NULL, page);
320 lock_page(page);
321 if (!PageUptodate(page)) {
322 unlock_page(page);
323 page_cache_release(page);
324 printk(KERN_ERR "btrfs: error reading free "
325 "space cache\n");
326 goto free_cache;
327 }
328 }
329 addr = kmap(page);
330
331 if (index == 0) {
332 u64 *gen;
333
334 /*
335 * We put a bogus crc in the front of the first page in
336 * case old kernels try to mount a fs with the new
337 * format to make sure they discard the cache.
338 */
339 addr += sizeof(u64);
340 offset += sizeof(u64);
341
342 gen = addr;
343 if (*gen != BTRFS_I(inode)->generation) {
344 printk(KERN_ERR "btrfs: space cache generation"
345 " (%llu) does not match inode (%llu)\n",
346 (unsigned long long)*gen,
347 (unsigned long long)
348 BTRFS_I(inode)->generation);
349 kunmap(page);
350 unlock_page(page);
351 page_cache_release(page);
352 goto free_cache;
353 }
354 addr += sizeof(u64);
355 offset += sizeof(u64);
356 }
357 entry = addr;
358
359 while (1) {
360 if (!num_entries)
361 break;
362
363 need_loop = 1;
364 e = kmem_cache_zalloc(btrfs_free_space_cachep,
365 GFP_NOFS);
366 if (!e) {
367 kunmap(page);
368 unlock_page(page);
369 page_cache_release(page);
370 goto free_cache;
371 }
372
373 e->offset = le64_to_cpu(entry->offset);
374 e->bytes = le64_to_cpu(entry->bytes);
375 if (!e->bytes) {
376 kunmap(page);
377 kmem_cache_free(btrfs_free_space_cachep, e);
378 unlock_page(page);
379 page_cache_release(page);
380 goto free_cache;
381 }
382
383 if (entry->type == BTRFS_FREE_SPACE_EXTENT) {
384 spin_lock(&ctl->tree_lock);
385 ret = link_free_space(ctl, e);
386 spin_unlock(&ctl->tree_lock);
387 if (ret) {
388 printk(KERN_ERR "Duplicate entries in "
389 "free space cache, dumping\n");
390 kunmap(page);
391 unlock_page(page);
392 page_cache_release(page);
393 goto free_cache;
394 }
395 } else {
396 e->bitmap = kzalloc(PAGE_CACHE_SIZE, GFP_NOFS);
397 if (!e->bitmap) {
398 kunmap(page);
399 kmem_cache_free(
400 btrfs_free_space_cachep, e);
401 unlock_page(page);
402 page_cache_release(page);
403 goto free_cache;
404 }
405 spin_lock(&ctl->tree_lock);
406 ret = link_free_space(ctl, e);
407 ctl->total_bitmaps++;
408 ctl->op->recalc_thresholds(ctl);
409 spin_unlock(&ctl->tree_lock);
410 if (ret) {
411 printk(KERN_ERR "Duplicate entries in "
412 "free space cache, dumping\n");
413 kunmap(page);
414 unlock_page(page);
415 page_cache_release(page);
416 goto free_cache;
417 }
418 list_add_tail(&e->list, &bitmaps);
419 }
420
421 num_entries--;
422 offset += sizeof(struct btrfs_free_space_entry);
423 if (offset + sizeof(struct btrfs_free_space_entry) >=
424 PAGE_CACHE_SIZE)
425 break;
426 entry++;
427 }
428
429 /*
430 * We read an entry out of this page, we need to move on to the
431 * next page.
432 */
433 if (need_loop) {
434 kunmap(page);
435 goto next;
436 }
437
438 /*
439 * We add the bitmaps at the end of the entries in order that
440 * the bitmap entries are added to the cache.
441 */
442 e = list_entry(bitmaps.next, struct btrfs_free_space, list);
443 list_del_init(&e->list);
444 memcpy(e->bitmap, addr, PAGE_CACHE_SIZE);
445 kunmap(page);
446 num_bitmaps--;
447 next:
448 unlock_page(page);
449 page_cache_release(page);
450 index++;
451 }
452
453 ret = 1;
454 out:
455 return ret;
456 free_cache:
457 __btrfs_remove_free_space_cache(ctl);
458 goto out;
459 }
460
461 int load_free_space_cache(struct btrfs_fs_info *fs_info,
462 struct btrfs_block_group_cache *block_group)
463 {
464 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
465 struct btrfs_root *root = fs_info->tree_root;
466 struct inode *inode;
467 struct btrfs_path *path;
468 int ret;
469 bool matched;
470 u64 used = btrfs_block_group_used(&block_group->item);
471
472 /*
473 * If we're unmounting then just return, since this does a search on the
474 * normal root and not the commit root and we could deadlock.
475 */
476 if (btrfs_fs_closing(fs_info))
477 return 0;
478
479 /*
480 * If this block group has been marked to be cleared for one reason or
481 * another then we can't trust the on disk cache, so just return.
482 */
483 spin_lock(&block_group->lock);
484 if (block_group->disk_cache_state != BTRFS_DC_WRITTEN) {
485 spin_unlock(&block_group->lock);
486 return 0;
487 }
488 spin_unlock(&block_group->lock);
489
490 path = btrfs_alloc_path();
491 if (!path)
492 return 0;
493
494 inode = lookup_free_space_inode(root, block_group, path);
495 if (IS_ERR(inode)) {
496 btrfs_free_path(path);
497 return 0;
498 }
499
500 ret = __load_free_space_cache(fs_info->tree_root, inode, ctl,
501 path, block_group->key.objectid);
502 btrfs_free_path(path);
503 if (ret <= 0)
504 goto out;
505
506 spin_lock(&ctl->tree_lock);
507 matched = (ctl->free_space == (block_group->key.offset - used -
508 block_group->bytes_super));
509 spin_unlock(&ctl->tree_lock);
510
511 if (!matched) {
512 __btrfs_remove_free_space_cache(ctl);
513 printk(KERN_ERR "block group %llu has an wrong amount of free "
514 "space\n", block_group->key.objectid);
515 ret = -1;
516 }
517 out:
518 if (ret < 0) {
519 /* This cache is bogus, make sure it gets cleared */
520 spin_lock(&block_group->lock);
521 block_group->disk_cache_state = BTRFS_DC_CLEAR;
522 spin_unlock(&block_group->lock);
523 ret = 0;
524
525 printk(KERN_ERR "btrfs: failed to load free space cache "
526 "for block group %llu\n", block_group->key.objectid);
527 }
528
529 iput(inode);
530 return ret;
531 }
532
533 int __btrfs_write_out_cache(struct btrfs_root *root, struct inode *inode,
534 struct btrfs_free_space_ctl *ctl,
535 struct btrfs_block_group_cache *block_group,
536 struct btrfs_trans_handle *trans,
537 struct btrfs_path *path, u64 offset)
538 {
539 struct btrfs_free_space_header *header;
540 struct extent_buffer *leaf;
541 struct rb_node *node;
542 struct list_head *pos, *n;
543 struct page **pages;
544 struct page *page;
545 struct extent_state *cached_state = NULL;
546 struct btrfs_free_cluster *cluster = NULL;
547 struct extent_io_tree *unpin = NULL;
548 struct list_head bitmap_list;
549 struct btrfs_key key;
550 u64 start, end, len;
551 u64 bytes = 0;
552 u32 crc = ~(u32)0;
553 int index = 0, num_pages = 0;
554 int entries = 0;
555 int bitmaps = 0;
556 int ret = -1;
557 bool next_page = false;
558 bool out_of_space = false;
559
560 INIT_LIST_HEAD(&bitmap_list);
561
562 node = rb_first(&ctl->free_space_offset);
563 if (!node)
564 return 0;
565
566 if (!i_size_read(inode))
567 return -1;
568
569 num_pages = (i_size_read(inode) + PAGE_CACHE_SIZE - 1) >>
570 PAGE_CACHE_SHIFT;
571
572 filemap_write_and_wait(inode->i_mapping);
573 btrfs_wait_ordered_range(inode, inode->i_size &
574 ~(root->sectorsize - 1), (u64)-1);
575
576 pages = kzalloc(sizeof(struct page *) * num_pages, GFP_NOFS);
577 if (!pages)
578 return -1;
579
580 /* Get the cluster for this block_group if it exists */
581 if (block_group && !list_empty(&block_group->cluster_list))
582 cluster = list_entry(block_group->cluster_list.next,
583 struct btrfs_free_cluster,
584 block_group_list);
585
586 /*
587 * We shouldn't have switched the pinned extents yet so this is the
588 * right one
589 */
590 unpin = root->fs_info->pinned_extents;
591
592 /*
593 * Lock all pages first so we can lock the extent safely.
594 *
595 * NOTE: Because we hold the ref the entire time we're going to write to
596 * the page find_get_page should never fail, so we don't do a check
597 * after find_get_page at this point. Just putting this here so people
598 * know and don't freak out.
599 */
600 while (index < num_pages) {
601 page = find_or_create_page(inode->i_mapping, index, GFP_NOFS);
602 if (!page) {
603 int i;
604
605 for (i = 0; i < num_pages; i++) {
606 unlock_page(pages[i]);
607 page_cache_release(pages[i]);
608 }
609 goto out;
610 }
611 pages[index] = page;
612 index++;
613 }
614
615 index = 0;
616 lock_extent_bits(&BTRFS_I(inode)->io_tree, 0, i_size_read(inode) - 1,
617 0, &cached_state, GFP_NOFS);
618
619 /*
620 * When searching for pinned extents, we need to start at our start
621 * offset.
622 */
623 if (block_group)
624 start = block_group->key.objectid;
625
626 /* Write out the extent entries */
627 do {
628 struct btrfs_free_space_entry *entry;
629 void *addr, *orig;
630 unsigned long offset = 0;
631
632 next_page = false;
633
634 if (index >= num_pages) {
635 out_of_space = true;
636 break;
637 }
638
639 page = pages[index];
640
641 orig = addr = kmap(page);
642 if (index == 0) {
643 u64 *gen;
644
645 /*
646 * We're going to put in a bogus crc for this page to
647 * make sure that old kernels who aren't aware of this
648 * format will be sure to discard the cache.
649 */
650 addr += sizeof(u64);
651 offset += sizeof(u64);
652
653 gen = addr;
654 *gen = trans->transid;
655 addr += sizeof(u64);
656 offset += sizeof(u64);
657 }
658 entry = addr;
659
660 memset(addr, 0, PAGE_CACHE_SIZE - offset);
661 while (node && !next_page) {
662 struct btrfs_free_space *e;
663
664 e = rb_entry(node, struct btrfs_free_space, offset_index);
665 entries++;
666
667 entry->offset = cpu_to_le64(e->offset);
668 entry->bytes = cpu_to_le64(e->bytes);
669 if (e->bitmap) {
670 entry->type = BTRFS_FREE_SPACE_BITMAP;
671 list_add_tail(&e->list, &bitmap_list);
672 bitmaps++;
673 } else {
674 entry->type = BTRFS_FREE_SPACE_EXTENT;
675 }
676 node = rb_next(node);
677 if (!node && cluster) {
678 node = rb_first(&cluster->root);
679 cluster = NULL;
680 }
681 offset += sizeof(struct btrfs_free_space_entry);
682 if (offset + sizeof(struct btrfs_free_space_entry) >=
683 PAGE_CACHE_SIZE)
684 next_page = true;
685 entry++;
686 }
687
688 /*
689 * We want to add any pinned extents to our free space cache
690 * so we don't leak the space
691 */
692 while (block_group && !next_page &&
693 (start < block_group->key.objectid +
694 block_group->key.offset)) {
695 ret = find_first_extent_bit(unpin, start, &start, &end,
696 EXTENT_DIRTY);
697 if (ret) {
698 ret = 0;
699 break;
700 }
701
702 /* This pinned extent is out of our range */
703 if (start >= block_group->key.objectid +
704 block_group->key.offset)
705 break;
706
707 len = block_group->key.objectid +
708 block_group->key.offset - start;
709 len = min(len, end + 1 - start);
710
711 entries++;
712 entry->offset = cpu_to_le64(start);
713 entry->bytes = cpu_to_le64(len);
714 entry->type = BTRFS_FREE_SPACE_EXTENT;
715
716 start = end + 1;
717 offset += sizeof(struct btrfs_free_space_entry);
718 if (offset + sizeof(struct btrfs_free_space_entry) >=
719 PAGE_CACHE_SIZE)
720 next_page = true;
721 entry++;
722 }
723
724 /* Generate bogus crc value */
725 if (index == 0) {
726 u32 *tmp;
727 crc = btrfs_csum_data(root, orig + sizeof(u64), crc,
728 PAGE_CACHE_SIZE - sizeof(u64));
729 btrfs_csum_final(crc, (char *)&crc);
730 crc++;
731 tmp = orig;
732 *tmp = crc;
733 }
734
735 kunmap(page);
736
737 bytes += PAGE_CACHE_SIZE;
738
739 index++;
740 } while (node || next_page);
741
742 /* Write out the bitmaps */
743 list_for_each_safe(pos, n, &bitmap_list) {
744 void *addr;
745 struct btrfs_free_space *entry =
746 list_entry(pos, struct btrfs_free_space, list);
747
748 if (index >= num_pages) {
749 out_of_space = true;
750 break;
751 }
752 page = pages[index];
753
754 addr = kmap(page);
755 memcpy(addr, entry->bitmap, PAGE_CACHE_SIZE);
756 kunmap(page);
757 bytes += PAGE_CACHE_SIZE;
758
759 list_del_init(&entry->list);
760 index++;
761 }
762
763 if (out_of_space) {
764 btrfs_drop_pages(pages, num_pages);
765 unlock_extent_cached(&BTRFS_I(inode)->io_tree, 0,
766 i_size_read(inode) - 1, &cached_state,
767 GFP_NOFS);
768 ret = 0;
769 goto out;
770 }
771
772 /* Zero out the rest of the pages just to make sure */
773 while (index < num_pages) {
774 void *addr;
775
776 page = pages[index];
777 addr = kmap(page);
778 memset(addr, 0, PAGE_CACHE_SIZE);
779 kunmap(page);
780 bytes += PAGE_CACHE_SIZE;
781 index++;
782 }
783
784 ret = btrfs_dirty_pages(root, inode, pages, num_pages, 0,
785 bytes, &cached_state);
786 btrfs_drop_pages(pages, num_pages);
787 unlock_extent_cached(&BTRFS_I(inode)->io_tree, 0,
788 i_size_read(inode) - 1, &cached_state, GFP_NOFS);
789
790 if (ret) {
791 ret = 0;
792 goto out;
793 }
794
795 BTRFS_I(inode)->generation = trans->transid;
796
797 filemap_write_and_wait(inode->i_mapping);
798
799 key.objectid = BTRFS_FREE_SPACE_OBJECTID;
800 key.offset = offset;
801 key.type = 0;
802
803 ret = btrfs_search_slot(trans, root, &key, path, 1, 1);
804 if (ret < 0) {
805 ret = -1;
806 clear_extent_bit(&BTRFS_I(inode)->io_tree, 0, bytes - 1,
807 EXTENT_DIRTY | EXTENT_DELALLOC |
808 EXTENT_DO_ACCOUNTING, 0, 0, NULL, GFP_NOFS);
809 goto out;
810 }
811 leaf = path->nodes[0];
812 if (ret > 0) {
813 struct btrfs_key found_key;
814 BUG_ON(!path->slots[0]);
815 path->slots[0]--;
816 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
817 if (found_key.objectid != BTRFS_FREE_SPACE_OBJECTID ||
818 found_key.offset != offset) {
819 ret = -1;
820 clear_extent_bit(&BTRFS_I(inode)->io_tree, 0, bytes - 1,
821 EXTENT_DIRTY | EXTENT_DELALLOC |
822 EXTENT_DO_ACCOUNTING, 0, 0, NULL,
823 GFP_NOFS);
824 btrfs_release_path(path);
825 goto out;
826 }
827 }
828 header = btrfs_item_ptr(leaf, path->slots[0],
829 struct btrfs_free_space_header);
830 btrfs_set_free_space_entries(leaf, header, entries);
831 btrfs_set_free_space_bitmaps(leaf, header, bitmaps);
832 btrfs_set_free_space_generation(leaf, header, trans->transid);
833 btrfs_mark_buffer_dirty(leaf);
834 btrfs_release_path(path);
835
836 ret = 1;
837
838 out:
839 kfree(pages);
840 if (ret != 1) {
841 invalidate_inode_pages2_range(inode->i_mapping, 0, index);
842 BTRFS_I(inode)->generation = 0;
843 }
844 btrfs_update_inode(trans, root, inode);
845 return ret;
846 }
847
848 int btrfs_write_out_cache(struct btrfs_root *root,
849 struct btrfs_trans_handle *trans,
850 struct btrfs_block_group_cache *block_group,
851 struct btrfs_path *path)
852 {
853 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
854 struct inode *inode;
855 int ret = 0;
856
857 root = root->fs_info->tree_root;
858
859 spin_lock(&block_group->lock);
860 if (block_group->disk_cache_state < BTRFS_DC_SETUP) {
861 spin_unlock(&block_group->lock);
862 return 0;
863 }
864 spin_unlock(&block_group->lock);
865
866 inode = lookup_free_space_inode(root, block_group, path);
867 if (IS_ERR(inode))
868 return 0;
869
870 ret = __btrfs_write_out_cache(root, inode, ctl, block_group, trans,
871 path, block_group->key.objectid);
872 if (ret < 0) {
873 spin_lock(&block_group->lock);
874 block_group->disk_cache_state = BTRFS_DC_ERROR;
875 spin_unlock(&block_group->lock);
876 ret = 0;
877
878 printk(KERN_ERR "btrfs: failed to write free space cace "
879 "for block group %llu\n", block_group->key.objectid);
880 }
881
882 iput(inode);
883 return ret;
884 }
885
886 static inline unsigned long offset_to_bit(u64 bitmap_start, u32 unit,
887 u64 offset)
888 {
889 BUG_ON(offset < bitmap_start);
890 offset -= bitmap_start;
891 return (unsigned long)(div_u64(offset, unit));
892 }
893
894 static inline unsigned long bytes_to_bits(u64 bytes, u32 unit)
895 {
896 return (unsigned long)(div_u64(bytes, unit));
897 }
898
899 static inline u64 offset_to_bitmap(struct btrfs_free_space_ctl *ctl,
900 u64 offset)
901 {
902 u64 bitmap_start;
903 u64 bytes_per_bitmap;
904
905 bytes_per_bitmap = BITS_PER_BITMAP * ctl->unit;
906 bitmap_start = offset - ctl->start;
907 bitmap_start = div64_u64(bitmap_start, bytes_per_bitmap);
908 bitmap_start *= bytes_per_bitmap;
909 bitmap_start += ctl->start;
910
911 return bitmap_start;
912 }
913
914 static int tree_insert_offset(struct rb_root *root, u64 offset,
915 struct rb_node *node, int bitmap)
916 {
917 struct rb_node **p = &root->rb_node;
918 struct rb_node *parent = NULL;
919 struct btrfs_free_space *info;
920
921 while (*p) {
922 parent = *p;
923 info = rb_entry(parent, struct btrfs_free_space, offset_index);
924
925 if (offset < info->offset) {
926 p = &(*p)->rb_left;
927 } else if (offset > info->offset) {
928 p = &(*p)->rb_right;
929 } else {
930 /*
931 * we could have a bitmap entry and an extent entry
932 * share the same offset. If this is the case, we want
933 * the extent entry to always be found first if we do a
934 * linear search through the tree, since we want to have
935 * the quickest allocation time, and allocating from an
936 * extent is faster than allocating from a bitmap. So
937 * if we're inserting a bitmap and we find an entry at
938 * this offset, we want to go right, or after this entry
939 * logically. If we are inserting an extent and we've
940 * found a bitmap, we want to go left, or before
941 * logically.
942 */
943 if (bitmap) {
944 if (info->bitmap) {
945 WARN_ON_ONCE(1);
946 return -EEXIST;
947 }
948 p = &(*p)->rb_right;
949 } else {
950 if (!info->bitmap) {
951 WARN_ON_ONCE(1);
952 return -EEXIST;
953 }
954 p = &(*p)->rb_left;
955 }
956 }
957 }
958
959 rb_link_node(node, parent, p);
960 rb_insert_color(node, root);
961
962 return 0;
963 }
964
965 /*
966 * searches the tree for the given offset.
967 *
968 * fuzzy - If this is set, then we are trying to make an allocation, and we just
969 * want a section that has at least bytes size and comes at or after the given
970 * offset.
971 */
972 static struct btrfs_free_space *
973 tree_search_offset(struct btrfs_free_space_ctl *ctl,
974 u64 offset, int bitmap_only, int fuzzy)
975 {
976 struct rb_node *n = ctl->free_space_offset.rb_node;
977 struct btrfs_free_space *entry, *prev = NULL;
978
979 /* find entry that is closest to the 'offset' */
980 while (1) {
981 if (!n) {
982 entry = NULL;
983 break;
984 }
985
986 entry = rb_entry(n, struct btrfs_free_space, offset_index);
987 prev = entry;
988
989 if (offset < entry->offset)
990 n = n->rb_left;
991 else if (offset > entry->offset)
992 n = n->rb_right;
993 else
994 break;
995 }
996
997 if (bitmap_only) {
998 if (!entry)
999 return NULL;
1000 if (entry->bitmap)
1001 return entry;
1002
1003 /*
1004 * bitmap entry and extent entry may share same offset,
1005 * in that case, bitmap entry comes after extent entry.
1006 */
1007 n = rb_next(n);
1008 if (!n)
1009 return NULL;
1010 entry = rb_entry(n, struct btrfs_free_space, offset_index);
1011 if (entry->offset != offset)
1012 return NULL;
1013
1014 WARN_ON(!entry->bitmap);
1015 return entry;
1016 } else if (entry) {
1017 if (entry->bitmap) {
1018 /*
1019 * if previous extent entry covers the offset,
1020 * we should return it instead of the bitmap entry
1021 */
1022 n = &entry->offset_index;
1023 while (1) {
1024 n = rb_prev(n);
1025 if (!n)
1026 break;
1027 prev = rb_entry(n, struct btrfs_free_space,
1028 offset_index);
1029 if (!prev->bitmap) {
1030 if (prev->offset + prev->bytes > offset)
1031 entry = prev;
1032 break;
1033 }
1034 }
1035 }
1036 return entry;
1037 }
1038
1039 if (!prev)
1040 return NULL;
1041
1042 /* find last entry before the 'offset' */
1043 entry = prev;
1044 if (entry->offset > offset) {
1045 n = rb_prev(&entry->offset_index);
1046 if (n) {
1047 entry = rb_entry(n, struct btrfs_free_space,
1048 offset_index);
1049 BUG_ON(entry->offset > offset);
1050 } else {
1051 if (fuzzy)
1052 return entry;
1053 else
1054 return NULL;
1055 }
1056 }
1057
1058 if (entry->bitmap) {
1059 n = &entry->offset_index;
1060 while (1) {
1061 n = rb_prev(n);
1062 if (!n)
1063 break;
1064 prev = rb_entry(n, struct btrfs_free_space,
1065 offset_index);
1066 if (!prev->bitmap) {
1067 if (prev->offset + prev->bytes > offset)
1068 return prev;
1069 break;
1070 }
1071 }
1072 if (entry->offset + BITS_PER_BITMAP * ctl->unit > offset)
1073 return entry;
1074 } else if (entry->offset + entry->bytes > offset)
1075 return entry;
1076
1077 if (!fuzzy)
1078 return NULL;
1079
1080 while (1) {
1081 if (entry->bitmap) {
1082 if (entry->offset + BITS_PER_BITMAP *
1083 ctl->unit > offset)
1084 break;
1085 } else {
1086 if (entry->offset + entry->bytes > offset)
1087 break;
1088 }
1089
1090 n = rb_next(&entry->offset_index);
1091 if (!n)
1092 return NULL;
1093 entry = rb_entry(n, struct btrfs_free_space, offset_index);
1094 }
1095 return entry;
1096 }
1097
1098 static inline void
1099 __unlink_free_space(struct btrfs_free_space_ctl *ctl,
1100 struct btrfs_free_space *info)
1101 {
1102 rb_erase(&info->offset_index, &ctl->free_space_offset);
1103 ctl->free_extents--;
1104 }
1105
1106 static void unlink_free_space(struct btrfs_free_space_ctl *ctl,
1107 struct btrfs_free_space *info)
1108 {
1109 __unlink_free_space(ctl, info);
1110 ctl->free_space -= info->bytes;
1111 }
1112
1113 static int link_free_space(struct btrfs_free_space_ctl *ctl,
1114 struct btrfs_free_space *info)
1115 {
1116 int ret = 0;
1117
1118 BUG_ON(!info->bitmap && !info->bytes);
1119 ret = tree_insert_offset(&ctl->free_space_offset, info->offset,
1120 &info->offset_index, (info->bitmap != NULL));
1121 if (ret)
1122 return ret;
1123
1124 ctl->free_space += info->bytes;
1125 ctl->free_extents++;
1126 return ret;
1127 }
1128
1129 static void recalculate_thresholds(struct btrfs_free_space_ctl *ctl)
1130 {
1131 struct btrfs_block_group_cache *block_group = ctl->private;
1132 u64 max_bytes;
1133 u64 bitmap_bytes;
1134 u64 extent_bytes;
1135 u64 size = block_group->key.offset;
1136 u64 bytes_per_bg = BITS_PER_BITMAP * block_group->sectorsize;
1137 int max_bitmaps = div64_u64(size + bytes_per_bg - 1, bytes_per_bg);
1138
1139 BUG_ON(ctl->total_bitmaps > max_bitmaps);
1140
1141 /*
1142 * The goal is to keep the total amount of memory used per 1gb of space
1143 * at or below 32k, so we need to adjust how much memory we allow to be
1144 * used by extent based free space tracking
1145 */
1146 if (size < 1024 * 1024 * 1024)
1147 max_bytes = MAX_CACHE_BYTES_PER_GIG;
1148 else
1149 max_bytes = MAX_CACHE_BYTES_PER_GIG *
1150 div64_u64(size, 1024 * 1024 * 1024);
1151
1152 /*
1153 * we want to account for 1 more bitmap than what we have so we can make
1154 * sure we don't go over our overall goal of MAX_CACHE_BYTES_PER_GIG as
1155 * we add more bitmaps.
1156 */
1157 bitmap_bytes = (ctl->total_bitmaps + 1) * PAGE_CACHE_SIZE;
1158
1159 if (bitmap_bytes >= max_bytes) {
1160 ctl->extents_thresh = 0;
1161 return;
1162 }
1163
1164 /*
1165 * we want the extent entry threshold to always be at most 1/2 the maxw
1166 * bytes we can have, or whatever is less than that.
1167 */
1168 extent_bytes = max_bytes - bitmap_bytes;
1169 extent_bytes = min_t(u64, extent_bytes, div64_u64(max_bytes, 2));
1170
1171 ctl->extents_thresh =
1172 div64_u64(extent_bytes, (sizeof(struct btrfs_free_space)));
1173 }
1174
1175 static inline void __bitmap_clear_bits(struct btrfs_free_space_ctl *ctl,
1176 struct btrfs_free_space *info,
1177 u64 offset, u64 bytes)
1178 {
1179 unsigned long start, count;
1180
1181 start = offset_to_bit(info->offset, ctl->unit, offset);
1182 count = bytes_to_bits(bytes, ctl->unit);
1183 BUG_ON(start + count > BITS_PER_BITMAP);
1184
1185 bitmap_clear(info->bitmap, start, count);
1186
1187 info->bytes -= bytes;
1188 }
1189
1190 static void bitmap_clear_bits(struct btrfs_free_space_ctl *ctl,
1191 struct btrfs_free_space *info, u64 offset,
1192 u64 bytes)
1193 {
1194 __bitmap_clear_bits(ctl, info, offset, bytes);
1195 ctl->free_space -= bytes;
1196 }
1197
1198 static void bitmap_set_bits(struct btrfs_free_space_ctl *ctl,
1199 struct btrfs_free_space *info, u64 offset,
1200 u64 bytes)
1201 {
1202 unsigned long start, count;
1203
1204 start = offset_to_bit(info->offset, ctl->unit, offset);
1205 count = bytes_to_bits(bytes, ctl->unit);
1206 BUG_ON(start + count > BITS_PER_BITMAP);
1207
1208 bitmap_set(info->bitmap, start, count);
1209
1210 info->bytes += bytes;
1211 ctl->free_space += bytes;
1212 }
1213
1214 static int search_bitmap(struct btrfs_free_space_ctl *ctl,
1215 struct btrfs_free_space *bitmap_info, u64 *offset,
1216 u64 *bytes)
1217 {
1218 unsigned long found_bits = 0;
1219 unsigned long bits, i;
1220 unsigned long next_zero;
1221
1222 i = offset_to_bit(bitmap_info->offset, ctl->unit,
1223 max_t(u64, *offset, bitmap_info->offset));
1224 bits = bytes_to_bits(*bytes, ctl->unit);
1225
1226 for (i = find_next_bit(bitmap_info->bitmap, BITS_PER_BITMAP, i);
1227 i < BITS_PER_BITMAP;
1228 i = find_next_bit(bitmap_info->bitmap, BITS_PER_BITMAP, i + 1)) {
1229 next_zero = find_next_zero_bit(bitmap_info->bitmap,
1230 BITS_PER_BITMAP, i);
1231 if ((next_zero - i) >= bits) {
1232 found_bits = next_zero - i;
1233 break;
1234 }
1235 i = next_zero;
1236 }
1237
1238 if (found_bits) {
1239 *offset = (u64)(i * ctl->unit) + bitmap_info->offset;
1240 *bytes = (u64)(found_bits) * ctl->unit;
1241 return 0;
1242 }
1243
1244 return -1;
1245 }
1246
1247 static struct btrfs_free_space *
1248 find_free_space(struct btrfs_free_space_ctl *ctl, u64 *offset, u64 *bytes)
1249 {
1250 struct btrfs_free_space *entry;
1251 struct rb_node *node;
1252 int ret;
1253
1254 if (!ctl->free_space_offset.rb_node)
1255 return NULL;
1256
1257 entry = tree_search_offset(ctl, offset_to_bitmap(ctl, *offset), 0, 1);
1258 if (!entry)
1259 return NULL;
1260
1261 for (node = &entry->offset_index; node; node = rb_next(node)) {
1262 entry = rb_entry(node, struct btrfs_free_space, offset_index);
1263 if (entry->bytes < *bytes)
1264 continue;
1265
1266 if (entry->bitmap) {
1267 ret = search_bitmap(ctl, entry, offset, bytes);
1268 if (!ret)
1269 return entry;
1270 continue;
1271 }
1272
1273 *offset = entry->offset;
1274 *bytes = entry->bytes;
1275 return entry;
1276 }
1277
1278 return NULL;
1279 }
1280
1281 static void add_new_bitmap(struct btrfs_free_space_ctl *ctl,
1282 struct btrfs_free_space *info, u64 offset)
1283 {
1284 info->offset = offset_to_bitmap(ctl, offset);
1285 info->bytes = 0;
1286 link_free_space(ctl, info);
1287 ctl->total_bitmaps++;
1288
1289 ctl->op->recalc_thresholds(ctl);
1290 }
1291
1292 static void free_bitmap(struct btrfs_free_space_ctl *ctl,
1293 struct btrfs_free_space *bitmap_info)
1294 {
1295 unlink_free_space(ctl, bitmap_info);
1296 kfree(bitmap_info->bitmap);
1297 kmem_cache_free(btrfs_free_space_cachep, bitmap_info);
1298 ctl->total_bitmaps--;
1299 ctl->op->recalc_thresholds(ctl);
1300 }
1301
1302 static noinline int remove_from_bitmap(struct btrfs_free_space_ctl *ctl,
1303 struct btrfs_free_space *bitmap_info,
1304 u64 *offset, u64 *bytes)
1305 {
1306 u64 end;
1307 u64 search_start, search_bytes;
1308 int ret;
1309
1310 again:
1311 end = bitmap_info->offset + (u64)(BITS_PER_BITMAP * ctl->unit) - 1;
1312
1313 /*
1314 * XXX - this can go away after a few releases.
1315 *
1316 * since the only user of btrfs_remove_free_space is the tree logging
1317 * stuff, and the only way to test that is under crash conditions, we
1318 * want to have this debug stuff here just in case somethings not
1319 * working. Search the bitmap for the space we are trying to use to
1320 * make sure its actually there. If its not there then we need to stop
1321 * because something has gone wrong.
1322 */
1323 search_start = *offset;
1324 search_bytes = *bytes;
1325 search_bytes = min(search_bytes, end - search_start + 1);
1326 ret = search_bitmap(ctl, bitmap_info, &search_start, &search_bytes);
1327 BUG_ON(ret < 0 || search_start != *offset);
1328
1329 if (*offset > bitmap_info->offset && *offset + *bytes > end) {
1330 bitmap_clear_bits(ctl, bitmap_info, *offset, end - *offset + 1);
1331 *bytes -= end - *offset + 1;
1332 *offset = end + 1;
1333 } else if (*offset >= bitmap_info->offset && *offset + *bytes <= end) {
1334 bitmap_clear_bits(ctl, bitmap_info, *offset, *bytes);
1335 *bytes = 0;
1336 }
1337
1338 if (*bytes) {
1339 struct rb_node *next = rb_next(&bitmap_info->offset_index);
1340 if (!bitmap_info->bytes)
1341 free_bitmap(ctl, bitmap_info);
1342
1343 /*
1344 * no entry after this bitmap, but we still have bytes to
1345 * remove, so something has gone wrong.
1346 */
1347 if (!next)
1348 return -EINVAL;
1349
1350 bitmap_info = rb_entry(next, struct btrfs_free_space,
1351 offset_index);
1352
1353 /*
1354 * if the next entry isn't a bitmap we need to return to let the
1355 * extent stuff do its work.
1356 */
1357 if (!bitmap_info->bitmap)
1358 return -EAGAIN;
1359
1360 /*
1361 * Ok the next item is a bitmap, but it may not actually hold
1362 * the information for the rest of this free space stuff, so
1363 * look for it, and if we don't find it return so we can try
1364 * everything over again.
1365 */
1366 search_start = *offset;
1367 search_bytes = *bytes;
1368 ret = search_bitmap(ctl, bitmap_info, &search_start,
1369 &search_bytes);
1370 if (ret < 0 || search_start != *offset)
1371 return -EAGAIN;
1372
1373 goto again;
1374 } else if (!bitmap_info->bytes)
1375 free_bitmap(ctl, bitmap_info);
1376
1377 return 0;
1378 }
1379
1380 static u64 add_bytes_to_bitmap(struct btrfs_free_space_ctl *ctl,
1381 struct btrfs_free_space *info, u64 offset,
1382 u64 bytes)
1383 {
1384 u64 bytes_to_set = 0;
1385 u64 end;
1386
1387 end = info->offset + (u64)(BITS_PER_BITMAP * ctl->unit);
1388
1389 bytes_to_set = min(end - offset, bytes);
1390
1391 bitmap_set_bits(ctl, info, offset, bytes_to_set);
1392
1393 return bytes_to_set;
1394
1395 }
1396
1397 static bool use_bitmap(struct btrfs_free_space_ctl *ctl,
1398 struct btrfs_free_space *info)
1399 {
1400 struct btrfs_block_group_cache *block_group = ctl->private;
1401
1402 /*
1403 * If we are below the extents threshold then we can add this as an
1404 * extent, and don't have to deal with the bitmap
1405 */
1406 if (ctl->free_extents < ctl->extents_thresh) {
1407 /*
1408 * If this block group has some small extents we don't want to
1409 * use up all of our free slots in the cache with them, we want
1410 * to reserve them to larger extents, however if we have plent
1411 * of cache left then go ahead an dadd them, no sense in adding
1412 * the overhead of a bitmap if we don't have to.
1413 */
1414 if (info->bytes <= block_group->sectorsize * 4) {
1415 if (ctl->free_extents * 2 <= ctl->extents_thresh)
1416 return false;
1417 } else {
1418 return false;
1419 }
1420 }
1421
1422 /*
1423 * some block groups are so tiny they can't be enveloped by a bitmap, so
1424 * don't even bother to create a bitmap for this
1425 */
1426 if (BITS_PER_BITMAP * block_group->sectorsize >
1427 block_group->key.offset)
1428 return false;
1429
1430 return true;
1431 }
1432
1433 static struct btrfs_free_space_op free_space_op = {
1434 .recalc_thresholds = recalculate_thresholds,
1435 .use_bitmap = use_bitmap,
1436 };
1437
1438 static int insert_into_bitmap(struct btrfs_free_space_ctl *ctl,
1439 struct btrfs_free_space *info)
1440 {
1441 struct btrfs_free_space *bitmap_info;
1442 struct btrfs_block_group_cache *block_group = NULL;
1443 int added = 0;
1444 u64 bytes, offset, bytes_added;
1445 int ret;
1446
1447 bytes = info->bytes;
1448 offset = info->offset;
1449
1450 if (!ctl->op->use_bitmap(ctl, info))
1451 return 0;
1452
1453 if (ctl->op == &free_space_op)
1454 block_group = ctl->private;
1455 again:
1456 /*
1457 * Since we link bitmaps right into the cluster we need to see if we
1458 * have a cluster here, and if so and it has our bitmap we need to add
1459 * the free space to that bitmap.
1460 */
1461 if (block_group && !list_empty(&block_group->cluster_list)) {
1462 struct btrfs_free_cluster *cluster;
1463 struct rb_node *node;
1464 struct btrfs_free_space *entry;
1465
1466 cluster = list_entry(block_group->cluster_list.next,
1467 struct btrfs_free_cluster,
1468 block_group_list);
1469 spin_lock(&cluster->lock);
1470 node = rb_first(&cluster->root);
1471 if (!node) {
1472 spin_unlock(&cluster->lock);
1473 goto no_cluster_bitmap;
1474 }
1475
1476 entry = rb_entry(node, struct btrfs_free_space, offset_index);
1477 if (!entry->bitmap) {
1478 spin_unlock(&cluster->lock);
1479 goto no_cluster_bitmap;
1480 }
1481
1482 if (entry->offset == offset_to_bitmap(ctl, offset)) {
1483 bytes_added = add_bytes_to_bitmap(ctl, entry,
1484 offset, bytes);
1485 bytes -= bytes_added;
1486 offset += bytes_added;
1487 }
1488 spin_unlock(&cluster->lock);
1489 if (!bytes) {
1490 ret = 1;
1491 goto out;
1492 }
1493 }
1494
1495 no_cluster_bitmap:
1496 bitmap_info = tree_search_offset(ctl, offset_to_bitmap(ctl, offset),
1497 1, 0);
1498 if (!bitmap_info) {
1499 BUG_ON(added);
1500 goto new_bitmap;
1501 }
1502
1503 bytes_added = add_bytes_to_bitmap(ctl, bitmap_info, offset, bytes);
1504 bytes -= bytes_added;
1505 offset += bytes_added;
1506 added = 0;
1507
1508 if (!bytes) {
1509 ret = 1;
1510 goto out;
1511 } else
1512 goto again;
1513
1514 new_bitmap:
1515 if (info && info->bitmap) {
1516 add_new_bitmap(ctl, info, offset);
1517 added = 1;
1518 info = NULL;
1519 goto again;
1520 } else {
1521 spin_unlock(&ctl->tree_lock);
1522
1523 /* no pre-allocated info, allocate a new one */
1524 if (!info) {
1525 info = kmem_cache_zalloc(btrfs_free_space_cachep,
1526 GFP_NOFS);
1527 if (!info) {
1528 spin_lock(&ctl->tree_lock);
1529 ret = -ENOMEM;
1530 goto out;
1531 }
1532 }
1533
1534 /* allocate the bitmap */
1535 info->bitmap = kzalloc(PAGE_CACHE_SIZE, GFP_NOFS);
1536 spin_lock(&ctl->tree_lock);
1537 if (!info->bitmap) {
1538 ret = -ENOMEM;
1539 goto out;
1540 }
1541 goto again;
1542 }
1543
1544 out:
1545 if (info) {
1546 if (info->bitmap)
1547 kfree(info->bitmap);
1548 kmem_cache_free(btrfs_free_space_cachep, info);
1549 }
1550
1551 return ret;
1552 }
1553
1554 static bool try_merge_free_space(struct btrfs_free_space_ctl *ctl,
1555 struct btrfs_free_space *info, bool update_stat)
1556 {
1557 struct btrfs_free_space *left_info;
1558 struct btrfs_free_space *right_info;
1559 bool merged = false;
1560 u64 offset = info->offset;
1561 u64 bytes = info->bytes;
1562
1563 /*
1564 * first we want to see if there is free space adjacent to the range we
1565 * are adding, if there is remove that struct and add a new one to
1566 * cover the entire range
1567 */
1568 right_info = tree_search_offset(ctl, offset + bytes, 0, 0);
1569 if (right_info && rb_prev(&right_info->offset_index))
1570 left_info = rb_entry(rb_prev(&right_info->offset_index),
1571 struct btrfs_free_space, offset_index);
1572 else
1573 left_info = tree_search_offset(ctl, offset - 1, 0, 0);
1574
1575 if (right_info && !right_info->bitmap) {
1576 if (update_stat)
1577 unlink_free_space(ctl, right_info);
1578 else
1579 __unlink_free_space(ctl, right_info);
1580 info->bytes += right_info->bytes;
1581 kmem_cache_free(btrfs_free_space_cachep, right_info);
1582 merged = true;
1583 }
1584
1585 if (left_info && !left_info->bitmap &&
1586 left_info->offset + left_info->bytes == offset) {
1587 if (update_stat)
1588 unlink_free_space(ctl, left_info);
1589 else
1590 __unlink_free_space(ctl, left_info);
1591 info->offset = left_info->offset;
1592 info->bytes += left_info->bytes;
1593 kmem_cache_free(btrfs_free_space_cachep, left_info);
1594 merged = true;
1595 }
1596
1597 return merged;
1598 }
1599
1600 int __btrfs_add_free_space(struct btrfs_free_space_ctl *ctl,
1601 u64 offset, u64 bytes)
1602 {
1603 struct btrfs_free_space *info;
1604 int ret = 0;
1605
1606 info = kmem_cache_zalloc(btrfs_free_space_cachep, GFP_NOFS);
1607 if (!info)
1608 return -ENOMEM;
1609
1610 info->offset = offset;
1611 info->bytes = bytes;
1612
1613 spin_lock(&ctl->tree_lock);
1614
1615 if (try_merge_free_space(ctl, info, true))
1616 goto link;
1617
1618 /*
1619 * There was no extent directly to the left or right of this new
1620 * extent then we know we're going to have to allocate a new extent, so
1621 * before we do that see if we need to drop this into a bitmap
1622 */
1623 ret = insert_into_bitmap(ctl, info);
1624 if (ret < 0) {
1625 goto out;
1626 } else if (ret) {
1627 ret = 0;
1628 goto out;
1629 }
1630 link:
1631 ret = link_free_space(ctl, info);
1632 if (ret)
1633 kmem_cache_free(btrfs_free_space_cachep, info);
1634 out:
1635 spin_unlock(&ctl->tree_lock);
1636
1637 if (ret) {
1638 printk(KERN_CRIT "btrfs: unable to add free space :%d\n", ret);
1639 BUG_ON(ret == -EEXIST);
1640 }
1641
1642 return ret;
1643 }
1644
1645 int btrfs_remove_free_space(struct btrfs_block_group_cache *block_group,
1646 u64 offset, u64 bytes)
1647 {
1648 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
1649 struct btrfs_free_space *info;
1650 struct btrfs_free_space *next_info = NULL;
1651 int ret = 0;
1652
1653 spin_lock(&ctl->tree_lock);
1654
1655 again:
1656 info = tree_search_offset(ctl, offset, 0, 0);
1657 if (!info) {
1658 /*
1659 * oops didn't find an extent that matched the space we wanted
1660 * to remove, look for a bitmap instead
1661 */
1662 info = tree_search_offset(ctl, offset_to_bitmap(ctl, offset),
1663 1, 0);
1664 if (!info) {
1665 WARN_ON(1);
1666 goto out_lock;
1667 }
1668 }
1669
1670 if (info->bytes < bytes && rb_next(&info->offset_index)) {
1671 u64 end;
1672 next_info = rb_entry(rb_next(&info->offset_index),
1673 struct btrfs_free_space,
1674 offset_index);
1675
1676 if (next_info->bitmap)
1677 end = next_info->offset +
1678 BITS_PER_BITMAP * ctl->unit - 1;
1679 else
1680 end = next_info->offset + next_info->bytes;
1681
1682 if (next_info->bytes < bytes ||
1683 next_info->offset > offset || offset > end) {
1684 printk(KERN_CRIT "Found free space at %llu, size %llu,"
1685 " trying to use %llu\n",
1686 (unsigned long long)info->offset,
1687 (unsigned long long)info->bytes,
1688 (unsigned long long)bytes);
1689 WARN_ON(1);
1690 ret = -EINVAL;
1691 goto out_lock;
1692 }
1693
1694 info = next_info;
1695 }
1696
1697 if (info->bytes == bytes) {
1698 unlink_free_space(ctl, info);
1699 if (info->bitmap) {
1700 kfree(info->bitmap);
1701 ctl->total_bitmaps--;
1702 }
1703 kmem_cache_free(btrfs_free_space_cachep, info);
1704 goto out_lock;
1705 }
1706
1707 if (!info->bitmap && info->offset == offset) {
1708 unlink_free_space(ctl, info);
1709 info->offset += bytes;
1710 info->bytes -= bytes;
1711 link_free_space(ctl, info);
1712 goto out_lock;
1713 }
1714
1715 if (!info->bitmap && info->offset <= offset &&
1716 info->offset + info->bytes >= offset + bytes) {
1717 u64 old_start = info->offset;
1718 /*
1719 * we're freeing space in the middle of the info,
1720 * this can happen during tree log replay
1721 *
1722 * first unlink the old info and then
1723 * insert it again after the hole we're creating
1724 */
1725 unlink_free_space(ctl, info);
1726 if (offset + bytes < info->offset + info->bytes) {
1727 u64 old_end = info->offset + info->bytes;
1728
1729 info->offset = offset + bytes;
1730 info->bytes = old_end - info->offset;
1731 ret = link_free_space(ctl, info);
1732 WARN_ON(ret);
1733 if (ret)
1734 goto out_lock;
1735 } else {
1736 /* the hole we're creating ends at the end
1737 * of the info struct, just free the info
1738 */
1739 kmem_cache_free(btrfs_free_space_cachep, info);
1740 }
1741 spin_unlock(&ctl->tree_lock);
1742
1743 /* step two, insert a new info struct to cover
1744 * anything before the hole
1745 */
1746 ret = btrfs_add_free_space(block_group, old_start,
1747 offset - old_start);
1748 WARN_ON(ret);
1749 goto out;
1750 }
1751
1752 ret = remove_from_bitmap(ctl, info, &offset, &bytes);
1753 if (ret == -EAGAIN)
1754 goto again;
1755 BUG_ON(ret);
1756 out_lock:
1757 spin_unlock(&ctl->tree_lock);
1758 out:
1759 return ret;
1760 }
1761
1762 void btrfs_dump_free_space(struct btrfs_block_group_cache *block_group,
1763 u64 bytes)
1764 {
1765 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
1766 struct btrfs_free_space *info;
1767 struct rb_node *n;
1768 int count = 0;
1769
1770 for (n = rb_first(&ctl->free_space_offset); n; n = rb_next(n)) {
1771 info = rb_entry(n, struct btrfs_free_space, offset_index);
1772 if (info->bytes >= bytes)
1773 count++;
1774 printk(KERN_CRIT "entry offset %llu, bytes %llu, bitmap %s\n",
1775 (unsigned long long)info->offset,
1776 (unsigned long long)info->bytes,
1777 (info->bitmap) ? "yes" : "no");
1778 }
1779 printk(KERN_INFO "block group has cluster?: %s\n",
1780 list_empty(&block_group->cluster_list) ? "no" : "yes");
1781 printk(KERN_INFO "%d blocks of free space at or bigger than bytes is"
1782 "\n", count);
1783 }
1784
1785 void btrfs_init_free_space_ctl(struct btrfs_block_group_cache *block_group)
1786 {
1787 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
1788
1789 spin_lock_init(&ctl->tree_lock);
1790 ctl->unit = block_group->sectorsize;
1791 ctl->start = block_group->key.objectid;
1792 ctl->private = block_group;
1793 ctl->op = &free_space_op;
1794
1795 /*
1796 * we only want to have 32k of ram per block group for keeping
1797 * track of free space, and if we pass 1/2 of that we want to
1798 * start converting things over to using bitmaps
1799 */
1800 ctl->extents_thresh = ((1024 * 32) / 2) /
1801 sizeof(struct btrfs_free_space);
1802 }
1803
1804 /*
1805 * for a given cluster, put all of its extents back into the free
1806 * space cache. If the block group passed doesn't match the block group
1807 * pointed to by the cluster, someone else raced in and freed the
1808 * cluster already. In that case, we just return without changing anything
1809 */
1810 static int
1811 __btrfs_return_cluster_to_free_space(
1812 struct btrfs_block_group_cache *block_group,
1813 struct btrfs_free_cluster *cluster)
1814 {
1815 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
1816 struct btrfs_free_space *entry;
1817 struct rb_node *node;
1818
1819 spin_lock(&cluster->lock);
1820 if (cluster->block_group != block_group)
1821 goto out;
1822
1823 cluster->block_group = NULL;
1824 cluster->window_start = 0;
1825 list_del_init(&cluster->block_group_list);
1826
1827 node = rb_first(&cluster->root);
1828 while (node) {
1829 bool bitmap;
1830
1831 entry = rb_entry(node, struct btrfs_free_space, offset_index);
1832 node = rb_next(&entry->offset_index);
1833 rb_erase(&entry->offset_index, &cluster->root);
1834
1835 bitmap = (entry->bitmap != NULL);
1836 if (!bitmap)
1837 try_merge_free_space(ctl, entry, false);
1838 tree_insert_offset(&ctl->free_space_offset,
1839 entry->offset, &entry->offset_index, bitmap);
1840 }
1841 cluster->root = RB_ROOT;
1842
1843 out:
1844 spin_unlock(&cluster->lock);
1845 btrfs_put_block_group(block_group);
1846 return 0;
1847 }
1848
1849 void __btrfs_remove_free_space_cache_locked(struct btrfs_free_space_ctl *ctl)
1850 {
1851 struct btrfs_free_space *info;
1852 struct rb_node *node;
1853
1854 while ((node = rb_last(&ctl->free_space_offset)) != NULL) {
1855 info = rb_entry(node, struct btrfs_free_space, offset_index);
1856 if (!info->bitmap) {
1857 unlink_free_space(ctl, info);
1858 kmem_cache_free(btrfs_free_space_cachep, info);
1859 } else {
1860 free_bitmap(ctl, info);
1861 }
1862 if (need_resched()) {
1863 spin_unlock(&ctl->tree_lock);
1864 cond_resched();
1865 spin_lock(&ctl->tree_lock);
1866 }
1867 }
1868 }
1869
1870 void __btrfs_remove_free_space_cache(struct btrfs_free_space_ctl *ctl)
1871 {
1872 spin_lock(&ctl->tree_lock);
1873 __btrfs_remove_free_space_cache_locked(ctl);
1874 spin_unlock(&ctl->tree_lock);
1875 }
1876
1877 void btrfs_remove_free_space_cache(struct btrfs_block_group_cache *block_group)
1878 {
1879 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
1880 struct btrfs_free_cluster *cluster;
1881 struct list_head *head;
1882
1883 spin_lock(&ctl->tree_lock);
1884 while ((head = block_group->cluster_list.next) !=
1885 &block_group->cluster_list) {
1886 cluster = list_entry(head, struct btrfs_free_cluster,
1887 block_group_list);
1888
1889 WARN_ON(cluster->block_group != block_group);
1890 __btrfs_return_cluster_to_free_space(block_group, cluster);
1891 if (need_resched()) {
1892 spin_unlock(&ctl->tree_lock);
1893 cond_resched();
1894 spin_lock(&ctl->tree_lock);
1895 }
1896 }
1897 __btrfs_remove_free_space_cache_locked(ctl);
1898 spin_unlock(&ctl->tree_lock);
1899
1900 }
1901
1902 u64 btrfs_find_space_for_alloc(struct btrfs_block_group_cache *block_group,
1903 u64 offset, u64 bytes, u64 empty_size)
1904 {
1905 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
1906 struct btrfs_free_space *entry = NULL;
1907 u64 bytes_search = bytes + empty_size;
1908 u64 ret = 0;
1909
1910 spin_lock(&ctl->tree_lock);
1911 entry = find_free_space(ctl, &offset, &bytes_search);
1912 if (!entry)
1913 goto out;
1914
1915 ret = offset;
1916 if (entry->bitmap) {
1917 bitmap_clear_bits(ctl, entry, offset, bytes);
1918 if (!entry->bytes)
1919 free_bitmap(ctl, entry);
1920 } else {
1921 unlink_free_space(ctl, entry);
1922 entry->offset += bytes;
1923 entry->bytes -= bytes;
1924 if (!entry->bytes)
1925 kmem_cache_free(btrfs_free_space_cachep, entry);
1926 else
1927 link_free_space(ctl, entry);
1928 }
1929
1930 out:
1931 spin_unlock(&ctl->tree_lock);
1932
1933 return ret;
1934 }
1935
1936 /*
1937 * given a cluster, put all of its extents back into the free space
1938 * cache. If a block group is passed, this function will only free
1939 * a cluster that belongs to the passed block group.
1940 *
1941 * Otherwise, it'll get a reference on the block group pointed to by the
1942 * cluster and remove the cluster from it.
1943 */
1944 int btrfs_return_cluster_to_free_space(
1945 struct btrfs_block_group_cache *block_group,
1946 struct btrfs_free_cluster *cluster)
1947 {
1948 struct btrfs_free_space_ctl *ctl;
1949 int ret;
1950
1951 /* first, get a safe pointer to the block group */
1952 spin_lock(&cluster->lock);
1953 if (!block_group) {
1954 block_group = cluster->block_group;
1955 if (!block_group) {
1956 spin_unlock(&cluster->lock);
1957 return 0;
1958 }
1959 } else if (cluster->block_group != block_group) {
1960 /* someone else has already freed it don't redo their work */
1961 spin_unlock(&cluster->lock);
1962 return 0;
1963 }
1964 atomic_inc(&block_group->count);
1965 spin_unlock(&cluster->lock);
1966
1967 ctl = block_group->free_space_ctl;
1968
1969 /* now return any extents the cluster had on it */
1970 spin_lock(&ctl->tree_lock);
1971 ret = __btrfs_return_cluster_to_free_space(block_group, cluster);
1972 spin_unlock(&ctl->tree_lock);
1973
1974 /* finally drop our ref */
1975 btrfs_put_block_group(block_group);
1976 return ret;
1977 }
1978
1979 static u64 btrfs_alloc_from_bitmap(struct btrfs_block_group_cache *block_group,
1980 struct btrfs_free_cluster *cluster,
1981 struct btrfs_free_space *entry,
1982 u64 bytes, u64 min_start)
1983 {
1984 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
1985 int err;
1986 u64 search_start = cluster->window_start;
1987 u64 search_bytes = bytes;
1988 u64 ret = 0;
1989
1990 search_start = min_start;
1991 search_bytes = bytes;
1992
1993 err = search_bitmap(ctl, entry, &search_start, &search_bytes);
1994 if (err)
1995 return 0;
1996
1997 ret = search_start;
1998 __bitmap_clear_bits(ctl, entry, ret, bytes);
1999
2000 return ret;
2001 }
2002
2003 /*
2004 * given a cluster, try to allocate 'bytes' from it, returns 0
2005 * if it couldn't find anything suitably large, or a logical disk offset
2006 * if things worked out
2007 */
2008 u64 btrfs_alloc_from_cluster(struct btrfs_block_group_cache *block_group,
2009 struct btrfs_free_cluster *cluster, u64 bytes,
2010 u64 min_start)
2011 {
2012 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2013 struct btrfs_free_space *entry = NULL;
2014 struct rb_node *node;
2015 u64 ret = 0;
2016
2017 spin_lock(&cluster->lock);
2018 if (bytes > cluster->max_size)
2019 goto out;
2020
2021 if (cluster->block_group != block_group)
2022 goto out;
2023
2024 node = rb_first(&cluster->root);
2025 if (!node)
2026 goto out;
2027
2028 entry = rb_entry(node, struct btrfs_free_space, offset_index);
2029 while(1) {
2030 if (entry->bytes < bytes ||
2031 (!entry->bitmap && entry->offset < min_start)) {
2032 node = rb_next(&entry->offset_index);
2033 if (!node)
2034 break;
2035 entry = rb_entry(node, struct btrfs_free_space,
2036 offset_index);
2037 continue;
2038 }
2039
2040 if (entry->bitmap) {
2041 ret = btrfs_alloc_from_bitmap(block_group,
2042 cluster, entry, bytes,
2043 min_start);
2044 if (ret == 0) {
2045 node = rb_next(&entry->offset_index);
2046 if (!node)
2047 break;
2048 entry = rb_entry(node, struct btrfs_free_space,
2049 offset_index);
2050 continue;
2051 }
2052 } else {
2053 ret = entry->offset;
2054
2055 entry->offset += bytes;
2056 entry->bytes -= bytes;
2057 }
2058
2059 if (entry->bytes == 0)
2060 rb_erase(&entry->offset_index, &cluster->root);
2061 break;
2062 }
2063 out:
2064 spin_unlock(&cluster->lock);
2065
2066 if (!ret)
2067 return 0;
2068
2069 spin_lock(&ctl->tree_lock);
2070
2071 ctl->free_space -= bytes;
2072 if (entry->bytes == 0) {
2073 ctl->free_extents--;
2074 if (entry->bitmap) {
2075 kfree(entry->bitmap);
2076 ctl->total_bitmaps--;
2077 ctl->op->recalc_thresholds(ctl);
2078 }
2079 kmem_cache_free(btrfs_free_space_cachep, entry);
2080 }
2081
2082 spin_unlock(&ctl->tree_lock);
2083
2084 return ret;
2085 }
2086
2087 static int btrfs_bitmap_cluster(struct btrfs_block_group_cache *block_group,
2088 struct btrfs_free_space *entry,
2089 struct btrfs_free_cluster *cluster,
2090 u64 offset, u64 bytes, u64 min_bytes)
2091 {
2092 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2093 unsigned long next_zero;
2094 unsigned long i;
2095 unsigned long search_bits;
2096 unsigned long total_bits;
2097 unsigned long found_bits;
2098 unsigned long start = 0;
2099 unsigned long total_found = 0;
2100 int ret;
2101 bool found = false;
2102
2103 i = offset_to_bit(entry->offset, block_group->sectorsize,
2104 max_t(u64, offset, entry->offset));
2105 search_bits = bytes_to_bits(bytes, block_group->sectorsize);
2106 total_bits = bytes_to_bits(min_bytes, block_group->sectorsize);
2107
2108 again:
2109 found_bits = 0;
2110 for (i = find_next_bit(entry->bitmap, BITS_PER_BITMAP, i);
2111 i < BITS_PER_BITMAP;
2112 i = find_next_bit(entry->bitmap, BITS_PER_BITMAP, i + 1)) {
2113 next_zero = find_next_zero_bit(entry->bitmap,
2114 BITS_PER_BITMAP, i);
2115 if (next_zero - i >= search_bits) {
2116 found_bits = next_zero - i;
2117 break;
2118 }
2119 i = next_zero;
2120 }
2121
2122 if (!found_bits)
2123 return -ENOSPC;
2124
2125 if (!found) {
2126 start = i;
2127 found = true;
2128 }
2129
2130 total_found += found_bits;
2131
2132 if (cluster->max_size < found_bits * block_group->sectorsize)
2133 cluster->max_size = found_bits * block_group->sectorsize;
2134
2135 if (total_found < total_bits) {
2136 i = find_next_bit(entry->bitmap, BITS_PER_BITMAP, next_zero);
2137 if (i - start > total_bits * 2) {
2138 total_found = 0;
2139 cluster->max_size = 0;
2140 found = false;
2141 }
2142 goto again;
2143 }
2144
2145 cluster->window_start = start * block_group->sectorsize +
2146 entry->offset;
2147 rb_erase(&entry->offset_index, &ctl->free_space_offset);
2148 ret = tree_insert_offset(&cluster->root, entry->offset,
2149 &entry->offset_index, 1);
2150 BUG_ON(ret);
2151
2152 return 0;
2153 }
2154
2155 /*
2156 * This searches the block group for just extents to fill the cluster with.
2157 */
2158 static noinline int
2159 setup_cluster_no_bitmap(struct btrfs_block_group_cache *block_group,
2160 struct btrfs_free_cluster *cluster,
2161 struct list_head *bitmaps, u64 offset, u64 bytes,
2162 u64 min_bytes)
2163 {
2164 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2165 struct btrfs_free_space *first = NULL;
2166 struct btrfs_free_space *entry = NULL;
2167 struct btrfs_free_space *prev = NULL;
2168 struct btrfs_free_space *last;
2169 struct rb_node *node;
2170 u64 window_start;
2171 u64 window_free;
2172 u64 max_extent;
2173 u64 max_gap = 128 * 1024;
2174
2175 entry = tree_search_offset(ctl, offset, 0, 1);
2176 if (!entry)
2177 return -ENOSPC;
2178
2179 /*
2180 * We don't want bitmaps, so just move along until we find a normal
2181 * extent entry.
2182 */
2183 while (entry->bitmap) {
2184 if (list_empty(&entry->list))
2185 list_add_tail(&entry->list, bitmaps);
2186 node = rb_next(&entry->offset_index);
2187 if (!node)
2188 return -ENOSPC;
2189 entry = rb_entry(node, struct btrfs_free_space, offset_index);
2190 }
2191
2192 window_start = entry->offset;
2193 window_free = entry->bytes;
2194 max_extent = entry->bytes;
2195 first = entry;
2196 last = entry;
2197 prev = entry;
2198
2199 while (window_free <= min_bytes) {
2200 node = rb_next(&entry->offset_index);
2201 if (!node)
2202 return -ENOSPC;
2203 entry = rb_entry(node, struct btrfs_free_space, offset_index);
2204
2205 if (entry->bitmap) {
2206 if (list_empty(&entry->list))
2207 list_add_tail(&entry->list, bitmaps);
2208 continue;
2209 }
2210
2211 /*
2212 * we haven't filled the empty size and the window is
2213 * very large. reset and try again
2214 */
2215 if (entry->offset - (prev->offset + prev->bytes) > max_gap ||
2216 entry->offset - window_start > (min_bytes * 2)) {
2217 first = entry;
2218 window_start = entry->offset;
2219 window_free = entry->bytes;
2220 last = entry;
2221 max_extent = entry->bytes;
2222 } else {
2223 last = entry;
2224 window_free += entry->bytes;
2225 if (entry->bytes > max_extent)
2226 max_extent = entry->bytes;
2227 }
2228 prev = entry;
2229 }
2230
2231 cluster->window_start = first->offset;
2232
2233 node = &first->offset_index;
2234
2235 /*
2236 * now we've found our entries, pull them out of the free space
2237 * cache and put them into the cluster rbtree
2238 */
2239 do {
2240 int ret;
2241
2242 entry = rb_entry(node, struct btrfs_free_space, offset_index);
2243 node = rb_next(&entry->offset_index);
2244 if (entry->bitmap)
2245 continue;
2246
2247 rb_erase(&entry->offset_index, &ctl->free_space_offset);
2248 ret = tree_insert_offset(&cluster->root, entry->offset,
2249 &entry->offset_index, 0);
2250 BUG_ON(ret);
2251 } while (node && entry != last);
2252
2253 cluster->max_size = max_extent;
2254
2255 return 0;
2256 }
2257
2258 /*
2259 * This specifically looks for bitmaps that may work in the cluster, we assume
2260 * that we have already failed to find extents that will work.
2261 */
2262 static noinline int
2263 setup_cluster_bitmap(struct btrfs_block_group_cache *block_group,
2264 struct btrfs_free_cluster *cluster,
2265 struct list_head *bitmaps, u64 offset, u64 bytes,
2266 u64 min_bytes)
2267 {
2268 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2269 struct btrfs_free_space *entry;
2270 struct rb_node *node;
2271 int ret = -ENOSPC;
2272
2273 if (ctl->total_bitmaps == 0)
2274 return -ENOSPC;
2275
2276 /*
2277 * First check our cached list of bitmaps and see if there is an entry
2278 * here that will work.
2279 */
2280 list_for_each_entry(entry, bitmaps, list) {
2281 if (entry->bytes < min_bytes)
2282 continue;
2283 ret = btrfs_bitmap_cluster(block_group, entry, cluster, offset,
2284 bytes, min_bytes);
2285 if (!ret)
2286 return 0;
2287 }
2288
2289 /*
2290 * If we do have entries on our list and we are here then we didn't find
2291 * anything, so go ahead and get the next entry after the last entry in
2292 * this list and start the search from there.
2293 */
2294 if (!list_empty(bitmaps)) {
2295 entry = list_entry(bitmaps->prev, struct btrfs_free_space,
2296 list);
2297 node = rb_next(&entry->offset_index);
2298 if (!node)
2299 return -ENOSPC;
2300 entry = rb_entry(node, struct btrfs_free_space, offset_index);
2301 goto search;
2302 }
2303
2304 entry = tree_search_offset(ctl, offset_to_bitmap(ctl, offset), 0, 1);
2305 if (!entry)
2306 return -ENOSPC;
2307
2308 search:
2309 node = &entry->offset_index;
2310 do {
2311 entry = rb_entry(node, struct btrfs_free_space, offset_index);
2312 node = rb_next(&entry->offset_index);
2313 if (!entry->bitmap)
2314 continue;
2315 if (entry->bytes < min_bytes)
2316 continue;
2317 ret = btrfs_bitmap_cluster(block_group, entry, cluster, offset,
2318 bytes, min_bytes);
2319 } while (ret && node);
2320
2321 return ret;
2322 }
2323
2324 /*
2325 * here we try to find a cluster of blocks in a block group. The goal
2326 * is to find at least bytes free and up to empty_size + bytes free.
2327 * We might not find them all in one contiguous area.
2328 *
2329 * returns zero and sets up cluster if things worked out, otherwise
2330 * it returns -enospc
2331 */
2332 int btrfs_find_space_cluster(struct btrfs_trans_handle *trans,
2333 struct btrfs_root *root,
2334 struct btrfs_block_group_cache *block_group,
2335 struct btrfs_free_cluster *cluster,
2336 u64 offset, u64 bytes, u64 empty_size)
2337 {
2338 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2339 struct list_head bitmaps;
2340 struct btrfs_free_space *entry, *tmp;
2341 u64 min_bytes;
2342 int ret;
2343
2344 /* for metadata, allow allocates with more holes */
2345 if (btrfs_test_opt(root, SSD_SPREAD)) {
2346 min_bytes = bytes + empty_size;
2347 } else if (block_group->flags & BTRFS_BLOCK_GROUP_METADATA) {
2348 /*
2349 * we want to do larger allocations when we are
2350 * flushing out the delayed refs, it helps prevent
2351 * making more work as we go along.
2352 */
2353 if (trans->transaction->delayed_refs.flushing)
2354 min_bytes = max(bytes, (bytes + empty_size) >> 1);
2355 else
2356 min_bytes = max(bytes, (bytes + empty_size) >> 4);
2357 } else
2358 min_bytes = max(bytes, (bytes + empty_size) >> 2);
2359
2360 spin_lock(&ctl->tree_lock);
2361
2362 /*
2363 * If we know we don't have enough space to make a cluster don't even
2364 * bother doing all the work to try and find one.
2365 */
2366 if (ctl->free_space < min_bytes) {
2367 spin_unlock(&ctl->tree_lock);
2368 return -ENOSPC;
2369 }
2370
2371 spin_lock(&cluster->lock);
2372
2373 /* someone already found a cluster, hooray */
2374 if (cluster->block_group) {
2375 ret = 0;
2376 goto out;
2377 }
2378
2379 INIT_LIST_HEAD(&bitmaps);
2380 ret = setup_cluster_no_bitmap(block_group, cluster, &bitmaps, offset,
2381 bytes, min_bytes);
2382 if (ret)
2383 ret = setup_cluster_bitmap(block_group, cluster, &bitmaps,
2384 offset, bytes, min_bytes);
2385
2386 /* Clear our temporary list */
2387 list_for_each_entry_safe(entry, tmp, &bitmaps, list)
2388 list_del_init(&entry->list);
2389
2390 if (!ret) {
2391 atomic_inc(&block_group->count);
2392 list_add_tail(&cluster->block_group_list,
2393 &block_group->cluster_list);
2394 cluster->block_group = block_group;
2395 }
2396 out:
2397 spin_unlock(&cluster->lock);
2398 spin_unlock(&ctl->tree_lock);
2399
2400 return ret;
2401 }
2402
2403 /*
2404 * simple code to zero out a cluster
2405 */
2406 void btrfs_init_free_cluster(struct btrfs_free_cluster *cluster)
2407 {
2408 spin_lock_init(&cluster->lock);
2409 spin_lock_init(&cluster->refill_lock);
2410 cluster->root = RB_ROOT;
2411 cluster->max_size = 0;
2412 INIT_LIST_HEAD(&cluster->block_group_list);
2413 cluster->block_group = NULL;
2414 }
2415
2416 int btrfs_trim_block_group(struct btrfs_block_group_cache *block_group,
2417 u64 *trimmed, u64 start, u64 end, u64 minlen)
2418 {
2419 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2420 struct btrfs_free_space *entry = NULL;
2421 struct btrfs_fs_info *fs_info = block_group->fs_info;
2422 u64 bytes = 0;
2423 u64 actually_trimmed;
2424 int ret = 0;
2425
2426 *trimmed = 0;
2427
2428 while (start < end) {
2429 spin_lock(&ctl->tree_lock);
2430
2431 if (ctl->free_space < minlen) {
2432 spin_unlock(&ctl->tree_lock);
2433 break;
2434 }
2435
2436 entry = tree_search_offset(ctl, start, 0, 1);
2437 if (!entry)
2438 entry = tree_search_offset(ctl,
2439 offset_to_bitmap(ctl, start),
2440 1, 1);
2441
2442 if (!entry || entry->offset >= end) {
2443 spin_unlock(&ctl->tree_lock);
2444 break;
2445 }
2446
2447 if (entry->bitmap) {
2448 ret = search_bitmap(ctl, entry, &start, &bytes);
2449 if (!ret) {
2450 if (start >= end) {
2451 spin_unlock(&ctl->tree_lock);
2452 break;
2453 }
2454 bytes = min(bytes, end - start);
2455 bitmap_clear_bits(ctl, entry, start, bytes);
2456 if (entry->bytes == 0)
2457 free_bitmap(ctl, entry);
2458 } else {
2459 start = entry->offset + BITS_PER_BITMAP *
2460 block_group->sectorsize;
2461 spin_unlock(&ctl->tree_lock);
2462 ret = 0;
2463 continue;
2464 }
2465 } else {
2466 start = entry->offset;
2467 bytes = min(entry->bytes, end - start);
2468 unlink_free_space(ctl, entry);
2469 kmem_cache_free(btrfs_free_space_cachep, entry);
2470 }
2471
2472 spin_unlock(&ctl->tree_lock);
2473
2474 if (bytes >= minlen) {
2475 int update_ret;
2476 update_ret = btrfs_update_reserved_bytes(block_group,
2477 bytes, 1, 1);
2478
2479 ret = btrfs_error_discard_extent(fs_info->extent_root,
2480 start,
2481 bytes,
2482 &actually_trimmed);
2483
2484 btrfs_add_free_space(block_group, start, bytes);
2485 if (!update_ret)
2486 btrfs_update_reserved_bytes(block_group,
2487 bytes, 0, 1);
2488
2489 if (ret)
2490 break;
2491 *trimmed += actually_trimmed;
2492 }
2493 start += bytes;
2494 bytes = 0;
2495
2496 if (fatal_signal_pending(current)) {
2497 ret = -ERESTARTSYS;
2498 break;
2499 }
2500
2501 cond_resched();
2502 }
2503
2504 return ret;
2505 }
2506
2507 /*
2508 * Find the left-most item in the cache tree, and then return the
2509 * smallest inode number in the item.
2510 *
2511 * Note: the returned inode number may not be the smallest one in
2512 * the tree, if the left-most item is a bitmap.
2513 */
2514 u64 btrfs_find_ino_for_alloc(struct btrfs_root *fs_root)
2515 {
2516 struct btrfs_free_space_ctl *ctl = fs_root->free_ino_ctl;
2517 struct btrfs_free_space *entry = NULL;
2518 u64 ino = 0;
2519
2520 spin_lock(&ctl->tree_lock);
2521
2522 if (RB_EMPTY_ROOT(&ctl->free_space_offset))
2523 goto out;
2524
2525 entry = rb_entry(rb_first(&ctl->free_space_offset),
2526 struct btrfs_free_space, offset_index);
2527
2528 if (!entry->bitmap) {
2529 ino = entry->offset;
2530
2531 unlink_free_space(ctl, entry);
2532 entry->offset++;
2533 entry->bytes--;
2534 if (!entry->bytes)
2535 kmem_cache_free(btrfs_free_space_cachep, entry);
2536 else
2537 link_free_space(ctl, entry);
2538 } else {
2539 u64 offset = 0;
2540 u64 count = 1;
2541 int ret;
2542
2543 ret = search_bitmap(ctl, entry, &offset, &count);
2544 BUG_ON(ret);
2545
2546 ino = offset;
2547 bitmap_clear_bits(ctl, entry, offset, 1);
2548 if (entry->bytes == 0)
2549 free_bitmap(ctl, entry);
2550 }
2551 out:
2552 spin_unlock(&ctl->tree_lock);
2553
2554 return ino;
2555 }
2556
2557 struct inode *lookup_free_ino_inode(struct btrfs_root *root,
2558 struct btrfs_path *path)
2559 {
2560 struct inode *inode = NULL;
2561
2562 spin_lock(&root->cache_lock);
2563 if (root->cache_inode)
2564 inode = igrab(root->cache_inode);
2565 spin_unlock(&root->cache_lock);
2566 if (inode)
2567 return inode;
2568
2569 inode = __lookup_free_space_inode(root, path, 0);
2570 if (IS_ERR(inode))
2571 return inode;
2572
2573 spin_lock(&root->cache_lock);
2574 if (!btrfs_fs_closing(root->fs_info))
2575 root->cache_inode = igrab(inode);
2576 spin_unlock(&root->cache_lock);
2577
2578 return inode;
2579 }
2580
2581 int create_free_ino_inode(struct btrfs_root *root,
2582 struct btrfs_trans_handle *trans,
2583 struct btrfs_path *path)
2584 {
2585 return __create_free_space_inode(root, trans, path,
2586 BTRFS_FREE_INO_OBJECTID, 0);
2587 }
2588
2589 int load_free_ino_cache(struct btrfs_fs_info *fs_info, struct btrfs_root *root)
2590 {
2591 struct btrfs_free_space_ctl *ctl = root->free_ino_ctl;
2592 struct btrfs_path *path;
2593 struct inode *inode;
2594 int ret = 0;
2595 u64 root_gen = btrfs_root_generation(&root->root_item);
2596
2597 if (!btrfs_test_opt(root, INODE_MAP_CACHE))
2598 return 0;
2599
2600 /*
2601 * If we're unmounting then just return, since this does a search on the
2602 * normal root and not the commit root and we could deadlock.
2603 */
2604 if (btrfs_fs_closing(fs_info))
2605 return 0;
2606
2607 path = btrfs_alloc_path();
2608 if (!path)
2609 return 0;
2610
2611 inode = lookup_free_ino_inode(root, path);
2612 if (IS_ERR(inode))
2613 goto out;
2614
2615 if (root_gen != BTRFS_I(inode)->generation)
2616 goto out_put;
2617
2618 ret = __load_free_space_cache(root, inode, ctl, path, 0);
2619
2620 if (ret < 0)
2621 printk(KERN_ERR "btrfs: failed to load free ino cache for "
2622 "root %llu\n", root->root_key.objectid);
2623 out_put:
2624 iput(inode);
2625 out:
2626 btrfs_free_path(path);
2627 return ret;
2628 }
2629
2630 int btrfs_write_out_ino_cache(struct btrfs_root *root,
2631 struct btrfs_trans_handle *trans,
2632 struct btrfs_path *path)
2633 {
2634 struct btrfs_free_space_ctl *ctl = root->free_ino_ctl;
2635 struct inode *inode;
2636 int ret;
2637
2638 if (!btrfs_test_opt(root, INODE_MAP_CACHE))
2639 return 0;
2640
2641 inode = lookup_free_ino_inode(root, path);
2642 if (IS_ERR(inode))
2643 return 0;
2644
2645 ret = __btrfs_write_out_cache(root, inode, ctl, NULL, trans, path, 0);
2646 if (ret < 0)
2647 printk(KERN_ERR "btrfs: failed to write free ino cache "
2648 "for root %llu\n", root->root_key.objectid);
2649
2650 iput(inode);
2651 return ret;
2652 }
Linux Btrfs Development