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mac80211: allow out-of-band EOSP notification
[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / fs / btrfs / free-space-cache.c
blob6377713f639c978db84f64dec2dc9541e8c8287e
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 loff_t oldsize;
194 int ret = 0;
195
196 trans->block_rsv = root->orphan_block_rsv;
197 ret = btrfs_block_rsv_check(trans, root,
198 root->orphan_block_rsv,
199 0, 5);
200 if (ret)
201 return ret;
202
203 oldsize = i_size_read(inode);
204 btrfs_i_size_write(inode, 0);
205 truncate_pagecache(inode, oldsize, 0);
206
207 /*
208 * We don't need an orphan item because truncating the free space cache
209 * will never be split across transactions.
210 */
211 ret = btrfs_truncate_inode_items(trans, root, inode,
212 0, BTRFS_EXTENT_DATA_KEY);
213 if (ret) {
214 WARN_ON(1);
215 return ret;
216 }
217
218 ret = btrfs_update_inode(trans, root, inode);
219 return ret;
220 }
221
222 static int readahead_cache(struct inode *inode)
223 {
224 struct file_ra_state *ra;
225 unsigned long last_index;
226
227 ra = kzalloc(sizeof(*ra), GFP_NOFS);
228 if (!ra)
229 return -ENOMEM;
230
231 file_ra_state_init(ra, inode->i_mapping);
232 last_index = (i_size_read(inode) - 1) >> PAGE_CACHE_SHIFT;
233
234 page_cache_sync_readahead(inode->i_mapping, ra, NULL, 0, last_index);
235
236 kfree(ra);
237
238 return 0;
239 }
240
241 int __load_free_space_cache(struct btrfs_root *root, struct inode *inode,
242 struct btrfs_free_space_ctl *ctl,
243 struct btrfs_path *path, u64 offset)
244 {
245 struct btrfs_free_space_header *header;
246 struct extent_buffer *leaf;
247 struct page *page;
248 struct btrfs_key key;
249 struct list_head bitmaps;
250 u64 num_entries;
251 u64 num_bitmaps;
252 u64 generation;
253 pgoff_t index = 0;
254 int ret = 0;
255
256 INIT_LIST_HEAD(&bitmaps);
257
258 /* Nothing in the space cache, goodbye */
259 if (!i_size_read(inode))
260 goto out;
261
262 key.objectid = BTRFS_FREE_SPACE_OBJECTID;
263 key.offset = offset;
264 key.type = 0;
265
266 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
267 if (ret < 0)
268 goto out;
269 else if (ret > 0) {
270 btrfs_release_path(path);
271 ret = 0;
272 goto out;
273 }
274
275 ret = -1;
276
277 leaf = path->nodes[0];
278 header = btrfs_item_ptr(leaf, path->slots[0],
279 struct btrfs_free_space_header);
280 num_entries = btrfs_free_space_entries(leaf, header);
281 num_bitmaps = btrfs_free_space_bitmaps(leaf, header);
282 generation = btrfs_free_space_generation(leaf, header);
283 btrfs_release_path(path);
284
285 if (BTRFS_I(inode)->generation != generation) {
286 printk(KERN_ERR "btrfs: free space inode generation (%llu) did"
287 " not match free space cache generation (%llu)\n",
288 (unsigned long long)BTRFS_I(inode)->generation,
289 (unsigned long long)generation);
290 goto out;
291 }
292
293 if (!num_entries)
294 goto out;
295
296 ret = readahead_cache(inode);
297 if (ret)
298 goto out;
299
300 while (1) {
301 struct btrfs_free_space_entry *entry;
302 struct btrfs_free_space *e;
303 void *addr;
304 unsigned long offset = 0;
305 int need_loop = 0;
306
307 if (!num_entries && !num_bitmaps)
308 break;
309
310 page = find_or_create_page(inode->i_mapping, index, GFP_NOFS);
311 if (!page)
312 goto free_cache;
313
314 if (!PageUptodate(page)) {
315 btrfs_readpage(NULL, page);
316 lock_page(page);
317 if (!PageUptodate(page)) {
318 unlock_page(page);
319 page_cache_release(page);
320 printk(KERN_ERR "btrfs: error reading free "
321 "space cache\n");
322 goto free_cache;
323 }
324 }
325 addr = kmap(page);
326
327 if (index == 0) {
328 u64 *gen;
329
330 /*
331 * We put a bogus crc in the front of the first page in
332 * case old kernels try to mount a fs with the new
333 * format to make sure they discard the cache.
334 */
335 addr += sizeof(u64);
336 offset += sizeof(u64);
337
338 gen = addr;
339 if (*gen != BTRFS_I(inode)->generation) {
340 printk(KERN_ERR "btrfs: space cache generation"
341 " (%llu) does not match inode (%llu)\n",
342 (unsigned long long)*gen,
343 (unsigned long long)
344 BTRFS_I(inode)->generation);
345 kunmap(page);
346 unlock_page(page);
347 page_cache_release(page);
348 goto free_cache;
349 }
350 addr += sizeof(u64);
351 offset += sizeof(u64);
352 }
353 entry = addr;
354
355 while (1) {
356 if (!num_entries)
357 break;
358
359 need_loop = 1;
360 e = kmem_cache_zalloc(btrfs_free_space_cachep,
361 GFP_NOFS);
362 if (!e) {
363 kunmap(page);
364 unlock_page(page);
365 page_cache_release(page);
366 goto free_cache;
367 }
368
369 e->offset = le64_to_cpu(entry->offset);
370 e->bytes = le64_to_cpu(entry->bytes);
371 if (!e->bytes) {
372 kunmap(page);
373 kmem_cache_free(btrfs_free_space_cachep, e);
374 unlock_page(page);
375 page_cache_release(page);
376 goto free_cache;
377 }
378
379 if (entry->type == BTRFS_FREE_SPACE_EXTENT) {
380 spin_lock(&ctl->tree_lock);
381 ret = link_free_space(ctl, e);
382 spin_unlock(&ctl->tree_lock);
383 if (ret) {
384 printk(KERN_ERR "Duplicate entries in "
385 "free space cache, dumping\n");
386 kunmap(page);
387 unlock_page(page);
388 page_cache_release(page);
389 goto free_cache;
390 }
391 } else {
392 e->bitmap = kzalloc(PAGE_CACHE_SIZE, GFP_NOFS);
393 if (!e->bitmap) {
394 kunmap(page);
395 kmem_cache_free(
396 btrfs_free_space_cachep, e);
397 unlock_page(page);
398 page_cache_release(page);
399 goto free_cache;
400 }
401 spin_lock(&ctl->tree_lock);
402 ret = link_free_space(ctl, e);
403 ctl->total_bitmaps++;
404 ctl->op->recalc_thresholds(ctl);
405 spin_unlock(&ctl->tree_lock);
406 if (ret) {
407 printk(KERN_ERR "Duplicate entries in "
408 "free space cache, dumping\n");
409 kunmap(page);
410 unlock_page(page);
411 page_cache_release(page);
412 goto free_cache;
413 }
414 list_add_tail(&e->list, &bitmaps);
415 }
416
417 num_entries--;
418 offset += sizeof(struct btrfs_free_space_entry);
419 if (offset + sizeof(struct btrfs_free_space_entry) >=
420 PAGE_CACHE_SIZE)
421 break;
422 entry++;
423 }
424
425 /*
426 * We read an entry out of this page, we need to move on to the
427 * next page.
428 */
429 if (need_loop) {
430 kunmap(page);
431 goto next;
432 }
433
434 /*
435 * We add the bitmaps at the end of the entries in order that
436 * the bitmap entries are added to the cache.
437 */
438 e = list_entry(bitmaps.next, struct btrfs_free_space, list);
439 list_del_init(&e->list);
440 memcpy(e->bitmap, addr, PAGE_CACHE_SIZE);
441 kunmap(page);
442 num_bitmaps--;
443 next:
444 unlock_page(page);
445 page_cache_release(page);
446 index++;
447 }
448
449 ret = 1;
450 out:
451 return ret;
452 free_cache:
453 __btrfs_remove_free_space_cache(ctl);
454 goto out;
455 }
456
457 int load_free_space_cache(struct btrfs_fs_info *fs_info,
458 struct btrfs_block_group_cache *block_group)
459 {
460 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
461 struct btrfs_root *root = fs_info->tree_root;
462 struct inode *inode;
463 struct btrfs_path *path;
464 int ret;
465 bool matched;
466 u64 used = btrfs_block_group_used(&block_group->item);
467
468 /*
469 * If we're unmounting then just return, since this does a search on the
470 * normal root and not the commit root and we could deadlock.
471 */
472 if (btrfs_fs_closing(fs_info))
473 return 0;
474
475 /*
476 * If this block group has been marked to be cleared for one reason or
477 * another then we can't trust the on disk cache, so just return.
478 */
479 spin_lock(&block_group->lock);
480 if (block_group->disk_cache_state != BTRFS_DC_WRITTEN) {
481 spin_unlock(&block_group->lock);
482 return 0;
483 }
484 spin_unlock(&block_group->lock);
485
486 path = btrfs_alloc_path();
487 if (!path)
488 return 0;
489
490 inode = lookup_free_space_inode(root, block_group, path);
491 if (IS_ERR(inode)) {
492 btrfs_free_path(path);
493 return 0;
494 }
495
496 ret = __load_free_space_cache(fs_info->tree_root, inode, ctl,
497 path, block_group->key.objectid);
498 btrfs_free_path(path);
499 if (ret <= 0)
500 goto out;
501
502 spin_lock(&ctl->tree_lock);
503 matched = (ctl->free_space == (block_group->key.offset - used -
504 block_group->bytes_super));
505 spin_unlock(&ctl->tree_lock);
506
507 if (!matched) {
508 __btrfs_remove_free_space_cache(ctl);
509 printk(KERN_ERR "block group %llu has an wrong amount of free "
510 "space\n", block_group->key.objectid);
511 ret = -1;
512 }
513 out:
514 if (ret < 0) {
515 /* This cache is bogus, make sure it gets cleared */
516 spin_lock(&block_group->lock);
517 block_group->disk_cache_state = BTRFS_DC_CLEAR;
518 spin_unlock(&block_group->lock);
519 ret = 0;
520
521 printk(KERN_ERR "btrfs: failed to load free space cache "
522 "for block group %llu\n", block_group->key.objectid);
523 }
524
525 iput(inode);
526 return ret;
527 }
528
529 int __btrfs_write_out_cache(struct btrfs_root *root, struct inode *inode,
530 struct btrfs_free_space_ctl *ctl,
531 struct btrfs_block_group_cache *block_group,
532 struct btrfs_trans_handle *trans,
533 struct btrfs_path *path, u64 offset)
534 {
535 struct btrfs_free_space_header *header;
536 struct extent_buffer *leaf;
537 struct rb_node *node;
538 struct list_head *pos, *n;
539 struct page **pages;
540 struct page *page;
541 struct extent_state *cached_state = NULL;
542 struct btrfs_free_cluster *cluster = NULL;
543 struct extent_io_tree *unpin = NULL;
544 struct list_head bitmap_list;
545 struct btrfs_key key;
546 u64 start, end, len;
547 u64 bytes = 0;
548 u32 crc = ~(u32)0;
549 int index = 0, num_pages = 0;
550 int entries = 0;
551 int bitmaps = 0;
552 int ret = -1;
553 bool next_page = false;
554 bool out_of_space = false;
555
556 INIT_LIST_HEAD(&bitmap_list);
557
558 node = rb_first(&ctl->free_space_offset);
559 if (!node)
560 return 0;
561
562 if (!i_size_read(inode))
563 return -1;
564
565 num_pages = (i_size_read(inode) + PAGE_CACHE_SIZE - 1) >>
566 PAGE_CACHE_SHIFT;
567
568 filemap_write_and_wait(inode->i_mapping);
569 btrfs_wait_ordered_range(inode, inode->i_size &
570 ~(root->sectorsize - 1), (u64)-1);
571
572 pages = kzalloc(sizeof(struct page *) * num_pages, GFP_NOFS);
573 if (!pages)
574 return -1;
575
576 /* Get the cluster for this block_group if it exists */
577 if (block_group && !list_empty(&block_group->cluster_list))
578 cluster = list_entry(block_group->cluster_list.next,
579 struct btrfs_free_cluster,
580 block_group_list);
581
582 /*
583 * We shouldn't have switched the pinned extents yet so this is the
584 * right one
585 */
586 unpin = root->fs_info->pinned_extents;
587
588 /*
589 * Lock all pages first so we can lock the extent safely.
590 *
591 * NOTE: Because we hold the ref the entire time we're going to write to
592 * the page find_get_page should never fail, so we don't do a check
593 * after find_get_page at this point. Just putting this here so people
594 * know and don't freak out.
595 */
596 while (index < num_pages) {
597 page = find_or_create_page(inode->i_mapping, index, GFP_NOFS);
598 if (!page) {
599 int i;
600
601 for (i = 0; i < num_pages; i++) {
602 unlock_page(pages[i]);
603 page_cache_release(pages[i]);
604 }
605 goto out;
606 }
607 pages[index] = page;
608 index++;
609 }
610
611 index = 0;
612 lock_extent_bits(&BTRFS_I(inode)->io_tree, 0, i_size_read(inode) - 1,
613 0, &cached_state, GFP_NOFS);
614
615 /*
616 * When searching for pinned extents, we need to start at our start
617 * offset.
618 */
619 if (block_group)
620 start = block_group->key.objectid;
621
622 /* Write out the extent entries */
623 do {
624 struct btrfs_free_space_entry *entry;
625 void *addr, *orig;
626 unsigned long offset = 0;
627
628 next_page = false;
629
630 if (index >= num_pages) {
631 out_of_space = true;
632 break;
633 }
634
635 page = pages[index];
636
637 orig = addr = kmap(page);
638 if (index == 0) {
639 u64 *gen;
640
641 /*
642 * We're going to put in a bogus crc for this page to
643 * make sure that old kernels who aren't aware of this
644 * format will be sure to discard the cache.
645 */
646 addr += sizeof(u64);
647 offset += sizeof(u64);
648
649 gen = addr;
650 *gen = trans->transid;
651 addr += sizeof(u64);
652 offset += sizeof(u64);
653 }
654 entry = addr;
655
656 memset(addr, 0, PAGE_CACHE_SIZE - offset);
657 while (node && !next_page) {
658 struct btrfs_free_space *e;
659
660 e = rb_entry(node, struct btrfs_free_space, offset_index);
661 entries++;
662
663 entry->offset = cpu_to_le64(e->offset);
664 entry->bytes = cpu_to_le64(e->bytes);
665 if (e->bitmap) {
666 entry->type = BTRFS_FREE_SPACE_BITMAP;
667 list_add_tail(&e->list, &bitmap_list);
668 bitmaps++;
669 } else {
670 entry->type = BTRFS_FREE_SPACE_EXTENT;
671 }
672 node = rb_next(node);
673 if (!node && cluster) {
674 node = rb_first(&cluster->root);
675 cluster = NULL;
676 }
677 offset += sizeof(struct btrfs_free_space_entry);
678 if (offset + sizeof(struct btrfs_free_space_entry) >=
679 PAGE_CACHE_SIZE)
680 next_page = true;
681 entry++;
682 }
683
684 /*
685 * We want to add any pinned extents to our free space cache
686 * so we don't leak the space
687 */
688 while (block_group && !next_page &&
689 (start < block_group->key.objectid +
690 block_group->key.offset)) {
691 ret = find_first_extent_bit(unpin, start, &start, &end,
692 EXTENT_DIRTY);
693 if (ret) {
694 ret = 0;
695 break;
696 }
697
698 /* This pinned extent is out of our range */
699 if (start >= block_group->key.objectid +
700 block_group->key.offset)
701 break;
702
703 len = block_group->key.objectid +
704 block_group->key.offset - start;
705 len = min(len, end + 1 - start);
706
707 entries++;
708 entry->offset = cpu_to_le64(start);
709 entry->bytes = cpu_to_le64(len);
710 entry->type = BTRFS_FREE_SPACE_EXTENT;
711
712 start = end + 1;
713 offset += sizeof(struct btrfs_free_space_entry);
714 if (offset + sizeof(struct btrfs_free_space_entry) >=
715 PAGE_CACHE_SIZE)
716 next_page = true;
717 entry++;
718 }
719
720 /* Generate bogus crc value */
721 if (index == 0) {
722 u32 *tmp;
723 crc = btrfs_csum_data(root, orig + sizeof(u64), crc,
724 PAGE_CACHE_SIZE - sizeof(u64));
725 btrfs_csum_final(crc, (char *)&crc);
726 crc++;
727 tmp = orig;
728 *tmp = crc;
729 }
730
731 kunmap(page);
732
733 bytes += PAGE_CACHE_SIZE;
734
735 index++;
736 } while (node || next_page);
737
738 /* Write out the bitmaps */
739 list_for_each_safe(pos, n, &bitmap_list) {
740 void *addr;
741 struct btrfs_free_space *entry =
742 list_entry(pos, struct btrfs_free_space, list);
743
744 if (index >= num_pages) {
745 out_of_space = true;
746 break;
747 }
748 page = pages[index];
749
750 addr = kmap(page);
751 memcpy(addr, entry->bitmap, PAGE_CACHE_SIZE);
752 kunmap(page);
753 bytes += PAGE_CACHE_SIZE;
754
755 list_del_init(&entry->list);
756 index++;
757 }
758
759 if (out_of_space) {
760 btrfs_drop_pages(pages, num_pages);
761 unlock_extent_cached(&BTRFS_I(inode)->io_tree, 0,
762 i_size_read(inode) - 1, &cached_state,
763 GFP_NOFS);
764 ret = 0;
765 goto out;
766 }
767
768 /* Zero out the rest of the pages just to make sure */
769 while (index < num_pages) {
770 void *addr;
771
772 page = pages[index];
773 addr = kmap(page);
774 memset(addr, 0, PAGE_CACHE_SIZE);
775 kunmap(page);
776 bytes += PAGE_CACHE_SIZE;
777 index++;
778 }
779
780 ret = btrfs_dirty_pages(root, inode, pages, num_pages, 0,
781 bytes, &cached_state);
782 btrfs_drop_pages(pages, num_pages);
783 unlock_extent_cached(&BTRFS_I(inode)->io_tree, 0,
784 i_size_read(inode) - 1, &cached_state, GFP_NOFS);
785
786 if (ret) {
787 ret = 0;
788 goto out;
789 }
790
791 BTRFS_I(inode)->generation = trans->transid;
792
793 filemap_write_and_wait(inode->i_mapping);
794
795 key.objectid = BTRFS_FREE_SPACE_OBJECTID;
796 key.offset = offset;
797 key.type = 0;
798
799 ret = btrfs_search_slot(trans, root, &key, path, 1, 1);
800 if (ret < 0) {
801 ret = -1;
802 clear_extent_bit(&BTRFS_I(inode)->io_tree, 0, bytes - 1,
803 EXTENT_DIRTY | EXTENT_DELALLOC |
804 EXTENT_DO_ACCOUNTING, 0, 0, NULL, GFP_NOFS);
805 goto out;
806 }
807 leaf = path->nodes[0];
808 if (ret > 0) {
809 struct btrfs_key found_key;
810 BUG_ON(!path->slots[0]);
811 path->slots[0]--;
812 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
813 if (found_key.objectid != BTRFS_FREE_SPACE_OBJECTID ||
814 found_key.offset != offset) {
815 ret = -1;
816 clear_extent_bit(&BTRFS_I(inode)->io_tree, 0, bytes - 1,
817 EXTENT_DIRTY | EXTENT_DELALLOC |
818 EXTENT_DO_ACCOUNTING, 0, 0, NULL,
819 GFP_NOFS);
820 btrfs_release_path(path);
821 goto out;
822 }
823 }
824 header = btrfs_item_ptr(leaf, path->slots[0],
825 struct btrfs_free_space_header);
826 btrfs_set_free_space_entries(leaf, header, entries);
827 btrfs_set_free_space_bitmaps(leaf, header, bitmaps);
828 btrfs_set_free_space_generation(leaf, header, trans->transid);
829 btrfs_mark_buffer_dirty(leaf);
830 btrfs_release_path(path);
831
832 ret = 1;
833
834 out:
835 kfree(pages);
836 if (ret != 1) {
837 invalidate_inode_pages2_range(inode->i_mapping, 0, index);
838 BTRFS_I(inode)->generation = 0;
839 }
840 btrfs_update_inode(trans, root, inode);
841 return ret;
842 }
843
844 int btrfs_write_out_cache(struct btrfs_root *root,
845 struct btrfs_trans_handle *trans,
846 struct btrfs_block_group_cache *block_group,
847 struct btrfs_path *path)
848 {
849 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
850 struct inode *inode;
851 int ret = 0;
852
853 root = root->fs_info->tree_root;
854
855 spin_lock(&block_group->lock);
856 if (block_group->disk_cache_state < BTRFS_DC_SETUP) {
857 spin_unlock(&block_group->lock);
858 return 0;
859 }
860 spin_unlock(&block_group->lock);
861
862 inode = lookup_free_space_inode(root, block_group, path);
863 if (IS_ERR(inode))
864 return 0;
865
866 ret = __btrfs_write_out_cache(root, inode, ctl, block_group, trans,
867 path, block_group->key.objectid);
868 if (ret < 0) {
869 spin_lock(&block_group->lock);
870 block_group->disk_cache_state = BTRFS_DC_ERROR;
871 spin_unlock(&block_group->lock);
872 ret = 0;
873
874 printk(KERN_ERR "btrfs: failed to write free space cace "
875 "for block group %llu\n", block_group->key.objectid);
876 }
877
878 iput(inode);
879 return ret;
880 }
881
882 static inline unsigned long offset_to_bit(u64 bitmap_start, u32 unit,
883 u64 offset)
884 {
885 BUG_ON(offset < bitmap_start);
886 offset -= bitmap_start;
887 return (unsigned long)(div_u64(offset, unit));
888 }
889
890 static inline unsigned long bytes_to_bits(u64 bytes, u32 unit)
891 {
892 return (unsigned long)(div_u64(bytes, unit));
893 }
894
895 static inline u64 offset_to_bitmap(struct btrfs_free_space_ctl *ctl,
896 u64 offset)
897 {
898 u64 bitmap_start;
899 u64 bytes_per_bitmap;
900
901 bytes_per_bitmap = BITS_PER_BITMAP * ctl->unit;
902 bitmap_start = offset - ctl->start;
903 bitmap_start = div64_u64(bitmap_start, bytes_per_bitmap);
904 bitmap_start *= bytes_per_bitmap;
905 bitmap_start += ctl->start;
906
907 return bitmap_start;
908 }
909
910 static int tree_insert_offset(struct rb_root *root, u64 offset,
911 struct rb_node *node, int bitmap)
912 {
913 struct rb_node **p = &root->rb_node;
914 struct rb_node *parent = NULL;
915 struct btrfs_free_space *info;
916
917 while (*p) {
918 parent = *p;
919 info = rb_entry(parent, struct btrfs_free_space, offset_index);
920
921 if (offset < info->offset) {
922 p = &(*p)->rb_left;
923 } else if (offset > info->offset) {
924 p = &(*p)->rb_right;
925 } else {
926 /*
927 * we could have a bitmap entry and an extent entry
928 * share the same offset. If this is the case, we want
929 * the extent entry to always be found first if we do a
930 * linear search through the tree, since we want to have
931 * the quickest allocation time, and allocating from an
932 * extent is faster than allocating from a bitmap. So
933 * if we're inserting a bitmap and we find an entry at
934 * this offset, we want to go right, or after this entry
935 * logically. If we are inserting an extent and we've
936 * found a bitmap, we want to go left, or before
937 * logically.
938 */
939 if (bitmap) {
940 if (info->bitmap) {
941 WARN_ON_ONCE(1);
942 return -EEXIST;
943 }
944 p = &(*p)->rb_right;
945 } else {
946 if (!info->bitmap) {
947 WARN_ON_ONCE(1);
948 return -EEXIST;
949 }
950 p = &(*p)->rb_left;
951 }
952 }
953 }
954
955 rb_link_node(node, parent, p);
956 rb_insert_color(node, root);
957
958 return 0;
959 }
960
961 /*
962 * searches the tree for the given offset.
963 *
964 * fuzzy - If this is set, then we are trying to make an allocation, and we just
965 * want a section that has at least bytes size and comes at or after the given
966 * offset.
967 */
968 static struct btrfs_free_space *
969 tree_search_offset(struct btrfs_free_space_ctl *ctl,
970 u64 offset, int bitmap_only, int fuzzy)
971 {
972 struct rb_node *n = ctl->free_space_offset.rb_node;
973 struct btrfs_free_space *entry, *prev = NULL;
974
975 /* find entry that is closest to the 'offset' */
976 while (1) {
977 if (!n) {
978 entry = NULL;
979 break;
980 }
981
982 entry = rb_entry(n, struct btrfs_free_space, offset_index);
983 prev = entry;
984
985 if (offset < entry->offset)
986 n = n->rb_left;
987 else if (offset > entry->offset)
988 n = n->rb_right;
989 else
990 break;
991 }
992
993 if (bitmap_only) {
994 if (!entry)
995 return NULL;
996 if (entry->bitmap)
997 return entry;
998
999 /*
1000 * bitmap entry and extent entry may share same offset,
1001 * in that case, bitmap entry comes after extent entry.
1002 */
1003 n = rb_next(n);
1004 if (!n)
1005 return NULL;
1006 entry = rb_entry(n, struct btrfs_free_space, offset_index);
1007 if (entry->offset != offset)
1008 return NULL;
1009
1010 WARN_ON(!entry->bitmap);
1011 return entry;
1012 } else if (entry) {
1013 if (entry->bitmap) {
1014 /*
1015 * if previous extent entry covers the offset,
1016 * we should return it instead of the bitmap entry
1017 */
1018 n = &entry->offset_index;
1019 while (1) {
1020 n = rb_prev(n);
1021 if (!n)
1022 break;
1023 prev = rb_entry(n, struct btrfs_free_space,
1024 offset_index);
1025 if (!prev->bitmap) {
1026 if (prev->offset + prev->bytes > offset)
1027 entry = prev;
1028 break;
1029 }
1030 }
1031 }
1032 return entry;
1033 }
1034
1035 if (!prev)
1036 return NULL;
1037
1038 /* find last entry before the 'offset' */
1039 entry = prev;
1040 if (entry->offset > offset) {
1041 n = rb_prev(&entry->offset_index);
1042 if (n) {
1043 entry = rb_entry(n, struct btrfs_free_space,
1044 offset_index);
1045 BUG_ON(entry->offset > offset);
1046 } else {
1047 if (fuzzy)
1048 return entry;
1049 else
1050 return NULL;
1051 }
1052 }
1053
1054 if (entry->bitmap) {
1055 n = &entry->offset_index;
1056 while (1) {
1057 n = rb_prev(n);
1058 if (!n)
1059 break;
1060 prev = rb_entry(n, struct btrfs_free_space,
1061 offset_index);
1062 if (!prev->bitmap) {
1063 if (prev->offset + prev->bytes > offset)
1064 return prev;
1065 break;
1066 }
1067 }
1068 if (entry->offset + BITS_PER_BITMAP * ctl->unit > offset)
1069 return entry;
1070 } else if (entry->offset + entry->bytes > offset)
1071 return entry;
1072
1073 if (!fuzzy)
1074 return NULL;
1075
1076 while (1) {
1077 if (entry->bitmap) {
1078 if (entry->offset + BITS_PER_BITMAP *
1079 ctl->unit > offset)
1080 break;
1081 } else {
1082 if (entry->offset + entry->bytes > offset)
1083 break;
1084 }
1085
1086 n = rb_next(&entry->offset_index);
1087 if (!n)
1088 return NULL;
1089 entry = rb_entry(n, struct btrfs_free_space, offset_index);
1090 }
1091 return entry;
1092 }
1093
1094 static inline void
1095 __unlink_free_space(struct btrfs_free_space_ctl *ctl,
1096 struct btrfs_free_space *info)
1097 {
1098 rb_erase(&info->offset_index, &ctl->free_space_offset);
1099 ctl->free_extents--;
1100 }
1101
1102 static void unlink_free_space(struct btrfs_free_space_ctl *ctl,
1103 struct btrfs_free_space *info)
1104 {
1105 __unlink_free_space(ctl, info);
1106 ctl->free_space -= info->bytes;
1107 }
1108
1109 static int link_free_space(struct btrfs_free_space_ctl *ctl,
1110 struct btrfs_free_space *info)
1111 {
1112 int ret = 0;
1113
1114 BUG_ON(!info->bitmap && !info->bytes);
1115 ret = tree_insert_offset(&ctl->free_space_offset, info->offset,
1116 &info->offset_index, (info->bitmap != NULL));
1117 if (ret)
1118 return ret;
1119
1120 ctl->free_space += info->bytes;
1121 ctl->free_extents++;
1122 return ret;
1123 }
1124
1125 static void recalculate_thresholds(struct btrfs_free_space_ctl *ctl)
1126 {
1127 struct btrfs_block_group_cache *block_group = ctl->private;
1128 u64 max_bytes;
1129 u64 bitmap_bytes;
1130 u64 extent_bytes;
1131 u64 size = block_group->key.offset;
1132 u64 bytes_per_bg = BITS_PER_BITMAP * block_group->sectorsize;
1133 int max_bitmaps = div64_u64(size + bytes_per_bg - 1, bytes_per_bg);
1134
1135 BUG_ON(ctl->total_bitmaps > max_bitmaps);
1136
1137 /*
1138 * The goal is to keep the total amount of memory used per 1gb of space
1139 * at or below 32k, so we need to adjust how much memory we allow to be
1140 * used by extent based free space tracking
1141 */
1142 if (size < 1024 * 1024 * 1024)
1143 max_bytes = MAX_CACHE_BYTES_PER_GIG;
1144 else
1145 max_bytes = MAX_CACHE_BYTES_PER_GIG *
1146 div64_u64(size, 1024 * 1024 * 1024);
1147
1148 /*
1149 * we want to account for 1 more bitmap than what we have so we can make
1150 * sure we don't go over our overall goal of MAX_CACHE_BYTES_PER_GIG as
1151 * we add more bitmaps.
1152 */
1153 bitmap_bytes = (ctl->total_bitmaps + 1) * PAGE_CACHE_SIZE;
1154
1155 if (bitmap_bytes >= max_bytes) {
1156 ctl->extents_thresh = 0;
1157 return;
1158 }
1159
1160 /*
1161 * we want the extent entry threshold to always be at most 1/2 the maxw
1162 * bytes we can have, or whatever is less than that.
1163 */
1164 extent_bytes = max_bytes - bitmap_bytes;
1165 extent_bytes = min_t(u64, extent_bytes, div64_u64(max_bytes, 2));
1166
1167 ctl->extents_thresh =
1168 div64_u64(extent_bytes, (sizeof(struct btrfs_free_space)));
1169 }
1170
1171 static void bitmap_clear_bits(struct btrfs_free_space_ctl *ctl,
1172 struct btrfs_free_space *info, u64 offset,
1173 u64 bytes)
1174 {
1175 unsigned long start, count;
1176
1177 start = offset_to_bit(info->offset, ctl->unit, offset);
1178 count = bytes_to_bits(bytes, ctl->unit);
1179 BUG_ON(start + count > BITS_PER_BITMAP);
1180
1181 bitmap_clear(info->bitmap, start, count);
1182
1183 info->bytes -= bytes;
1184 ctl->free_space -= bytes;
1185 }
1186
1187 static void bitmap_set_bits(struct btrfs_free_space_ctl *ctl,
1188 struct btrfs_free_space *info, u64 offset,
1189 u64 bytes)
1190 {
1191 unsigned long start, count;
1192
1193 start = offset_to_bit(info->offset, ctl->unit, offset);
1194 count = bytes_to_bits(bytes, ctl->unit);
1195 BUG_ON(start + count > BITS_PER_BITMAP);
1196
1197 bitmap_set(info->bitmap, start, count);
1198
1199 info->bytes += bytes;
1200 ctl->free_space += bytes;
1201 }
1202
1203 static int search_bitmap(struct btrfs_free_space_ctl *ctl,
1204 struct btrfs_free_space *bitmap_info, u64 *offset,
1205 u64 *bytes)
1206 {
1207 unsigned long found_bits = 0;
1208 unsigned long bits, i;
1209 unsigned long next_zero;
1210
1211 i = offset_to_bit(bitmap_info->offset, ctl->unit,
1212 max_t(u64, *offset, bitmap_info->offset));
1213 bits = bytes_to_bits(*bytes, ctl->unit);
1214
1215 for (i = find_next_bit(bitmap_info->bitmap, BITS_PER_BITMAP, i);
1216 i < BITS_PER_BITMAP;
1217 i = find_next_bit(bitmap_info->bitmap, BITS_PER_BITMAP, i + 1)) {
1218 next_zero = find_next_zero_bit(bitmap_info->bitmap,
1219 BITS_PER_BITMAP, i);
1220 if ((next_zero - i) >= bits) {
1221 found_bits = next_zero - i;
1222 break;
1223 }
1224 i = next_zero;
1225 }
1226
1227 if (found_bits) {
1228 *offset = (u64)(i * ctl->unit) + bitmap_info->offset;
1229 *bytes = (u64)(found_bits) * ctl->unit;
1230 return 0;
1231 }
1232
1233 return -1;
1234 }
1235
1236 static struct btrfs_free_space *
1237 find_free_space(struct btrfs_free_space_ctl *ctl, u64 *offset, u64 *bytes)
1238 {
1239 struct btrfs_free_space *entry;
1240 struct rb_node *node;
1241 int ret;
1242
1243 if (!ctl->free_space_offset.rb_node)
1244 return NULL;
1245
1246 entry = tree_search_offset(ctl, offset_to_bitmap(ctl, *offset), 0, 1);
1247 if (!entry)
1248 return NULL;
1249
1250 for (node = &entry->offset_index; node; node = rb_next(node)) {
1251 entry = rb_entry(node, struct btrfs_free_space, offset_index);
1252 if (entry->bytes < *bytes)
1253 continue;
1254
1255 if (entry->bitmap) {
1256 ret = search_bitmap(ctl, entry, offset, bytes);
1257 if (!ret)
1258 return entry;
1259 continue;
1260 }
1261
1262 *offset = entry->offset;
1263 *bytes = entry->bytes;
1264 return entry;
1265 }
1266
1267 return NULL;
1268 }
1269
1270 static void add_new_bitmap(struct btrfs_free_space_ctl *ctl,
1271 struct btrfs_free_space *info, u64 offset)
1272 {
1273 info->offset = offset_to_bitmap(ctl, offset);
1274 info->bytes = 0;
1275 link_free_space(ctl, info);
1276 ctl->total_bitmaps++;
1277
1278 ctl->op->recalc_thresholds(ctl);
1279 }
1280
1281 static void free_bitmap(struct btrfs_free_space_ctl *ctl,
1282 struct btrfs_free_space *bitmap_info)
1283 {
1284 unlink_free_space(ctl, bitmap_info);
1285 kfree(bitmap_info->bitmap);
1286 kmem_cache_free(btrfs_free_space_cachep, bitmap_info);
1287 ctl->total_bitmaps--;
1288 ctl->op->recalc_thresholds(ctl);
1289 }
1290
1291 static noinline int remove_from_bitmap(struct btrfs_free_space_ctl *ctl,
1292 struct btrfs_free_space *bitmap_info,
1293 u64 *offset, u64 *bytes)
1294 {
1295 u64 end;
1296 u64 search_start, search_bytes;
1297 int ret;
1298
1299 again:
1300 end = bitmap_info->offset + (u64)(BITS_PER_BITMAP * ctl->unit) - 1;
1301
1302 /*
1303 * XXX - this can go away after a few releases.
1304 *
1305 * since the only user of btrfs_remove_free_space is the tree logging
1306 * stuff, and the only way to test that is under crash conditions, we
1307 * want to have this debug stuff here just in case somethings not
1308 * working. Search the bitmap for the space we are trying to use to
1309 * make sure its actually there. If its not there then we need to stop
1310 * because something has gone wrong.
1311 */
1312 search_start = *offset;
1313 search_bytes = *bytes;
1314 search_bytes = min(search_bytes, end - search_start + 1);
1315 ret = search_bitmap(ctl, bitmap_info, &search_start, &search_bytes);
1316 BUG_ON(ret < 0 || search_start != *offset);
1317
1318 if (*offset > bitmap_info->offset && *offset + *bytes > end) {
1319 bitmap_clear_bits(ctl, bitmap_info, *offset, end - *offset + 1);
1320 *bytes -= end - *offset + 1;
1321 *offset = end + 1;
1322 } else if (*offset >= bitmap_info->offset && *offset + *bytes <= end) {
1323 bitmap_clear_bits(ctl, bitmap_info, *offset, *bytes);
1324 *bytes = 0;
1325 }
1326
1327 if (*bytes) {
1328 struct rb_node *next = rb_next(&bitmap_info->offset_index);
1329 if (!bitmap_info->bytes)
1330 free_bitmap(ctl, bitmap_info);
1331
1332 /*
1333 * no entry after this bitmap, but we still have bytes to
1334 * remove, so something has gone wrong.
1335 */
1336 if (!next)
1337 return -EINVAL;
1338
1339 bitmap_info = rb_entry(next, struct btrfs_free_space,
1340 offset_index);
1341
1342 /*
1343 * if the next entry isn't a bitmap we need to return to let the
1344 * extent stuff do its work.
1345 */
1346 if (!bitmap_info->bitmap)
1347 return -EAGAIN;
1348
1349 /*
1350 * Ok the next item is a bitmap, but it may not actually hold
1351 * the information for the rest of this free space stuff, so
1352 * look for it, and if we don't find it return so we can try
1353 * everything over again.
1354 */
1355 search_start = *offset;
1356 search_bytes = *bytes;
1357 ret = search_bitmap(ctl, bitmap_info, &search_start,
1358 &search_bytes);
1359 if (ret < 0 || search_start != *offset)
1360 return -EAGAIN;
1361
1362 goto again;
1363 } else if (!bitmap_info->bytes)
1364 free_bitmap(ctl, bitmap_info);
1365
1366 return 0;
1367 }
1368
1369 static u64 add_bytes_to_bitmap(struct btrfs_free_space_ctl *ctl,
1370 struct btrfs_free_space *info, u64 offset,
1371 u64 bytes)
1372 {
1373 u64 bytes_to_set = 0;
1374 u64 end;
1375
1376 end = info->offset + (u64)(BITS_PER_BITMAP * ctl->unit);
1377
1378 bytes_to_set = min(end - offset, bytes);
1379
1380 bitmap_set_bits(ctl, info, offset, bytes_to_set);
1381
1382 return bytes_to_set;
1383
1384 }
1385
1386 static bool use_bitmap(struct btrfs_free_space_ctl *ctl,
1387 struct btrfs_free_space *info)
1388 {
1389 struct btrfs_block_group_cache *block_group = ctl->private;
1390
1391 /*
1392 * If we are below the extents threshold then we can add this as an
1393 * extent, and don't have to deal with the bitmap
1394 */
1395 if (ctl->free_extents < ctl->extents_thresh) {
1396 /*
1397 * If this block group has some small extents we don't want to
1398 * use up all of our free slots in the cache with them, we want
1399 * to reserve them to larger extents, however if we have plent
1400 * of cache left then go ahead an dadd them, no sense in adding
1401 * the overhead of a bitmap if we don't have to.
1402 */
1403 if (info->bytes <= block_group->sectorsize * 4) {
1404 if (ctl->free_extents * 2 <= ctl->extents_thresh)
1405 return false;
1406 } else {
1407 return false;
1408 }
1409 }
1410
1411 /*
1412 * some block groups are so tiny they can't be enveloped by a bitmap, so
1413 * don't even bother to create a bitmap for this
1414 */
1415 if (BITS_PER_BITMAP * block_group->sectorsize >
1416 block_group->key.offset)
1417 return false;
1418
1419 return true;
1420 }
1421
1422 static struct btrfs_free_space_op free_space_op = {
1423 .recalc_thresholds = recalculate_thresholds,
1424 .use_bitmap = use_bitmap,
1425 };
1426
1427 static int insert_into_bitmap(struct btrfs_free_space_ctl *ctl,
1428 struct btrfs_free_space *info)
1429 {
1430 struct btrfs_free_space *bitmap_info;
1431 struct btrfs_block_group_cache *block_group = NULL;
1432 int added = 0;
1433 u64 bytes, offset, bytes_added;
1434 int ret;
1435
1436 bytes = info->bytes;
1437 offset = info->offset;
1438
1439 if (!ctl->op->use_bitmap(ctl, info))
1440 return 0;
1441
1442 if (ctl->op == &free_space_op)
1443 block_group = ctl->private;
1444 again:
1445 /*
1446 * Since we link bitmaps right into the cluster we need to see if we
1447 * have a cluster here, and if so and it has our bitmap we need to add
1448 * the free space to that bitmap.
1449 */
1450 if (block_group && !list_empty(&block_group->cluster_list)) {
1451 struct btrfs_free_cluster *cluster;
1452 struct rb_node *node;
1453 struct btrfs_free_space *entry;
1454
1455 cluster = list_entry(block_group->cluster_list.next,
1456 struct btrfs_free_cluster,
1457 block_group_list);
1458 spin_lock(&cluster->lock);
1459 node = rb_first(&cluster->root);
1460 if (!node) {
1461 spin_unlock(&cluster->lock);
1462 goto no_cluster_bitmap;
1463 }
1464
1465 entry = rb_entry(node, struct btrfs_free_space, offset_index);
1466 if (!entry->bitmap) {
1467 spin_unlock(&cluster->lock);
1468 goto no_cluster_bitmap;
1469 }
1470
1471 if (entry->offset == offset_to_bitmap(ctl, offset)) {
1472 bytes_added = add_bytes_to_bitmap(ctl, entry,
1473 offset, bytes);
1474 bytes -= bytes_added;
1475 offset += bytes_added;
1476 }
1477 spin_unlock(&cluster->lock);
1478 if (!bytes) {
1479 ret = 1;
1480 goto out;
1481 }
1482 }
1483
1484 no_cluster_bitmap:
1485 bitmap_info = tree_search_offset(ctl, offset_to_bitmap(ctl, offset),
1486 1, 0);
1487 if (!bitmap_info) {
1488 BUG_ON(added);
1489 goto new_bitmap;
1490 }
1491
1492 bytes_added = add_bytes_to_bitmap(ctl, bitmap_info, offset, bytes);
1493 bytes -= bytes_added;
1494 offset += bytes_added;
1495 added = 0;
1496
1497 if (!bytes) {
1498 ret = 1;
1499 goto out;
1500 } else
1501 goto again;
1502
1503 new_bitmap:
1504 if (info && info->bitmap) {
1505 add_new_bitmap(ctl, info, offset);
1506 added = 1;
1507 info = NULL;
1508 goto again;
1509 } else {
1510 spin_unlock(&ctl->tree_lock);
1511
1512 /* no pre-allocated info, allocate a new one */
1513 if (!info) {
1514 info = kmem_cache_zalloc(btrfs_free_space_cachep,
1515 GFP_NOFS);
1516 if (!info) {
1517 spin_lock(&ctl->tree_lock);
1518 ret = -ENOMEM;
1519 goto out;
1520 }
1521 }
1522
1523 /* allocate the bitmap */
1524 info->bitmap = kzalloc(PAGE_CACHE_SIZE, GFP_NOFS);
1525 spin_lock(&ctl->tree_lock);
1526 if (!info->bitmap) {
1527 ret = -ENOMEM;
1528 goto out;
1529 }
1530 goto again;
1531 }
1532
1533 out:
1534 if (info) {
1535 if (info->bitmap)
1536 kfree(info->bitmap);
1537 kmem_cache_free(btrfs_free_space_cachep, info);
1538 }
1539
1540 return ret;
1541 }
1542
1543 static bool try_merge_free_space(struct btrfs_free_space_ctl *ctl,
1544 struct btrfs_free_space *info, bool update_stat)
1545 {
1546 struct btrfs_free_space *left_info;
1547 struct btrfs_free_space *right_info;
1548 bool merged = false;
1549 u64 offset = info->offset;
1550 u64 bytes = info->bytes;
1551
1552 /*
1553 * first we want to see if there is free space adjacent to the range we
1554 * are adding, if there is remove that struct and add a new one to
1555 * cover the entire range
1556 */
1557 right_info = tree_search_offset(ctl, offset + bytes, 0, 0);
1558 if (right_info && rb_prev(&right_info->offset_index))
1559 left_info = rb_entry(rb_prev(&right_info->offset_index),
1560 struct btrfs_free_space, offset_index);
1561 else
1562 left_info = tree_search_offset(ctl, offset - 1, 0, 0);
1563
1564 if (right_info && !right_info->bitmap) {
1565 if (update_stat)
1566 unlink_free_space(ctl, right_info);
1567 else
1568 __unlink_free_space(ctl, right_info);
1569 info->bytes += right_info->bytes;
1570 kmem_cache_free(btrfs_free_space_cachep, right_info);
1571 merged = true;
1572 }
1573
1574 if (left_info && !left_info->bitmap &&
1575 left_info->offset + left_info->bytes == offset) {
1576 if (update_stat)
1577 unlink_free_space(ctl, left_info);
1578 else
1579 __unlink_free_space(ctl, left_info);
1580 info->offset = left_info->offset;
1581 info->bytes += left_info->bytes;
1582 kmem_cache_free(btrfs_free_space_cachep, left_info);
1583 merged = true;
1584 }
1585
1586 return merged;
1587 }
1588
1589 int __btrfs_add_free_space(struct btrfs_free_space_ctl *ctl,
1590 u64 offset, u64 bytes)
1591 {
1592 struct btrfs_free_space *info;
1593 int ret = 0;
1594
1595 info = kmem_cache_zalloc(btrfs_free_space_cachep, GFP_NOFS);
1596 if (!info)
1597 return -ENOMEM;
1598
1599 info->offset = offset;
1600 info->bytes = bytes;
1601
1602 spin_lock(&ctl->tree_lock);
1603
1604 if (try_merge_free_space(ctl, info, true))
1605 goto link;
1606
1607 /*
1608 * There was no extent directly to the left or right of this new
1609 * extent then we know we're going to have to allocate a new extent, so
1610 * before we do that see if we need to drop this into a bitmap
1611 */
1612 ret = insert_into_bitmap(ctl, info);
1613 if (ret < 0) {
1614 goto out;
1615 } else if (ret) {
1616 ret = 0;
1617 goto out;
1618 }
1619 link:
1620 ret = link_free_space(ctl, info);
1621 if (ret)
1622 kmem_cache_free(btrfs_free_space_cachep, info);
1623 out:
1624 spin_unlock(&ctl->tree_lock);
1625
1626 if (ret) {
1627 printk(KERN_CRIT "btrfs: unable to add free space :%d\n", ret);
1628 BUG_ON(ret == -EEXIST);
1629 }
1630
1631 return ret;
1632 }
1633
1634 int btrfs_remove_free_space(struct btrfs_block_group_cache *block_group,
1635 u64 offset, u64 bytes)
1636 {
1637 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
1638 struct btrfs_free_space *info;
1639 struct btrfs_free_space *next_info = NULL;
1640 int ret = 0;
1641
1642 spin_lock(&ctl->tree_lock);
1643
1644 again:
1645 info = tree_search_offset(ctl, offset, 0, 0);
1646 if (!info) {
1647 /*
1648 * oops didn't find an extent that matched the space we wanted
1649 * to remove, look for a bitmap instead
1650 */
1651 info = tree_search_offset(ctl, offset_to_bitmap(ctl, offset),
1652 1, 0);
1653 if (!info) {
1654 WARN_ON(1);
1655 goto out_lock;
1656 }
1657 }
1658
1659 if (info->bytes < bytes && rb_next(&info->offset_index)) {
1660 u64 end;
1661 next_info = rb_entry(rb_next(&info->offset_index),
1662 struct btrfs_free_space,
1663 offset_index);
1664
1665 if (next_info->bitmap)
1666 end = next_info->offset +
1667 BITS_PER_BITMAP * ctl->unit - 1;
1668 else
1669 end = next_info->offset + next_info->bytes;
1670
1671 if (next_info->bytes < bytes ||
1672 next_info->offset > offset || offset > end) {
1673 printk(KERN_CRIT "Found free space at %llu, size %llu,"
1674 " trying to use %llu\n",
1675 (unsigned long long)info->offset,
1676 (unsigned long long)info->bytes,
1677 (unsigned long long)bytes);
1678 WARN_ON(1);
1679 ret = -EINVAL;
1680 goto out_lock;
1681 }
1682
1683 info = next_info;
1684 }
1685
1686 if (info->bytes == bytes) {
1687 unlink_free_space(ctl, info);
1688 if (info->bitmap) {
1689 kfree(info->bitmap);
1690 ctl->total_bitmaps--;
1691 }
1692 kmem_cache_free(btrfs_free_space_cachep, info);
1693 goto out_lock;
1694 }
1695
1696 if (!info->bitmap && info->offset == offset) {
1697 unlink_free_space(ctl, info);
1698 info->offset += bytes;
1699 info->bytes -= bytes;
1700 link_free_space(ctl, info);
1701 goto out_lock;
1702 }
1703
1704 if (!info->bitmap && info->offset <= offset &&
1705 info->offset + info->bytes >= offset + bytes) {
1706 u64 old_start = info->offset;
1707 /*
1708 * we're freeing space in the middle of the info,
1709 * this can happen during tree log replay
1710 *
1711 * first unlink the old info and then
1712 * insert it again after the hole we're creating
1713 */
1714 unlink_free_space(ctl, info);
1715 if (offset + bytes < info->offset + info->bytes) {
1716 u64 old_end = info->offset + info->bytes;
1717
1718 info->offset = offset + bytes;
1719 info->bytes = old_end - info->offset;
1720 ret = link_free_space(ctl, info);
1721 WARN_ON(ret);
1722 if (ret)
1723 goto out_lock;
1724 } else {
1725 /* the hole we're creating ends at the end
1726 * of the info struct, just free the info
1727 */
1728 kmem_cache_free(btrfs_free_space_cachep, info);
1729 }
1730 spin_unlock(&ctl->tree_lock);
1731
1732 /* step two, insert a new info struct to cover
1733 * anything before the hole
1734 */
1735 ret = btrfs_add_free_space(block_group, old_start,
1736 offset - old_start);
1737 WARN_ON(ret);
1738 goto out;
1739 }
1740
1741 ret = remove_from_bitmap(ctl, info, &offset, &bytes);
1742 if (ret == -EAGAIN)
1743 goto again;
1744 BUG_ON(ret);
1745 out_lock:
1746 spin_unlock(&ctl->tree_lock);
1747 out:
1748 return ret;
1749 }
1750
1751 void btrfs_dump_free_space(struct btrfs_block_group_cache *block_group,
1752 u64 bytes)
1753 {
1754 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
1755 struct btrfs_free_space *info;
1756 struct rb_node *n;
1757 int count = 0;
1758
1759 for (n = rb_first(&ctl->free_space_offset); n; n = rb_next(n)) {
1760 info = rb_entry(n, struct btrfs_free_space, offset_index);
1761 if (info->bytes >= bytes)
1762 count++;
1763 printk(KERN_CRIT "entry offset %llu, bytes %llu, bitmap %s\n",
1764 (unsigned long long)info->offset,
1765 (unsigned long long)info->bytes,
1766 (info->bitmap) ? "yes" : "no");
1767 }
1768 printk(KERN_INFO "block group has cluster?: %s\n",
1769 list_empty(&block_group->cluster_list) ? "no" : "yes");
1770 printk(KERN_INFO "%d blocks of free space at or bigger than bytes is"
1771 "\n", count);
1772 }
1773
1774 void btrfs_init_free_space_ctl(struct btrfs_block_group_cache *block_group)
1775 {
1776 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
1777
1778 spin_lock_init(&ctl->tree_lock);
1779 ctl->unit = block_group->sectorsize;
1780 ctl->start = block_group->key.objectid;
1781 ctl->private = block_group;
1782 ctl->op = &free_space_op;
1783
1784 /*
1785 * we only want to have 32k of ram per block group for keeping
1786 * track of free space, and if we pass 1/2 of that we want to
1787 * start converting things over to using bitmaps
1788 */
1789 ctl->extents_thresh = ((1024 * 32) / 2) /
1790 sizeof(struct btrfs_free_space);
1791 }
1792
1793 /*
1794 * for a given cluster, put all of its extents back into the free
1795 * space cache. If the block group passed doesn't match the block group
1796 * pointed to by the cluster, someone else raced in and freed the
1797 * cluster already. In that case, we just return without changing anything
1798 */
1799 static int
1800 __btrfs_return_cluster_to_free_space(
1801 struct btrfs_block_group_cache *block_group,
1802 struct btrfs_free_cluster *cluster)
1803 {
1804 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
1805 struct btrfs_free_space *entry;
1806 struct rb_node *node;
1807
1808 spin_lock(&cluster->lock);
1809 if (cluster->block_group != block_group)
1810 goto out;
1811
1812 cluster->block_group = NULL;
1813 cluster->window_start = 0;
1814 list_del_init(&cluster->block_group_list);
1815
1816 node = rb_first(&cluster->root);
1817 while (node) {
1818 bool bitmap;
1819
1820 entry = rb_entry(node, struct btrfs_free_space, offset_index);
1821 node = rb_next(&entry->offset_index);
1822 rb_erase(&entry->offset_index, &cluster->root);
1823
1824 bitmap = (entry->bitmap != NULL);
1825 if (!bitmap)
1826 try_merge_free_space(ctl, entry, false);
1827 tree_insert_offset(&ctl->free_space_offset,
1828 entry->offset, &entry->offset_index, bitmap);
1829 }
1830 cluster->root = RB_ROOT;
1831
1832 out:
1833 spin_unlock(&cluster->lock);
1834 btrfs_put_block_group(block_group);
1835 return 0;
1836 }
1837
1838 void __btrfs_remove_free_space_cache_locked(struct btrfs_free_space_ctl *ctl)
1839 {
1840 struct btrfs_free_space *info;
1841 struct rb_node *node;
1842
1843 while ((node = rb_last(&ctl->free_space_offset)) != NULL) {
1844 info = rb_entry(node, struct btrfs_free_space, offset_index);
1845 if (!info->bitmap) {
1846 unlink_free_space(ctl, info);
1847 kmem_cache_free(btrfs_free_space_cachep, info);
1848 } else {
1849 free_bitmap(ctl, info);
1850 }
1851 if (need_resched()) {
1852 spin_unlock(&ctl->tree_lock);
1853 cond_resched();
1854 spin_lock(&ctl->tree_lock);
1855 }
1856 }
1857 }
1858
1859 void __btrfs_remove_free_space_cache(struct btrfs_free_space_ctl *ctl)
1860 {
1861 spin_lock(&ctl->tree_lock);
1862 __btrfs_remove_free_space_cache_locked(ctl);
1863 spin_unlock(&ctl->tree_lock);
1864 }
1865
1866 void btrfs_remove_free_space_cache(struct btrfs_block_group_cache *block_group)
1867 {
1868 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
1869 struct btrfs_free_cluster *cluster;
1870 struct list_head *head;
1871
1872 spin_lock(&ctl->tree_lock);
1873 while ((head = block_group->cluster_list.next) !=
1874 &block_group->cluster_list) {
1875 cluster = list_entry(head, struct btrfs_free_cluster,
1876 block_group_list);
1877
1878 WARN_ON(cluster->block_group != block_group);
1879 __btrfs_return_cluster_to_free_space(block_group, cluster);
1880 if (need_resched()) {
1881 spin_unlock(&ctl->tree_lock);
1882 cond_resched();
1883 spin_lock(&ctl->tree_lock);
1884 }
1885 }
1886 __btrfs_remove_free_space_cache_locked(ctl);
1887 spin_unlock(&ctl->tree_lock);
1888
1889 }
1890
1891 u64 btrfs_find_space_for_alloc(struct btrfs_block_group_cache *block_group,
1892 u64 offset, u64 bytes, u64 empty_size)
1893 {
1894 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
1895 struct btrfs_free_space *entry = NULL;
1896 u64 bytes_search = bytes + empty_size;
1897 u64 ret = 0;
1898
1899 spin_lock(&ctl->tree_lock);
1900 entry = find_free_space(ctl, &offset, &bytes_search);
1901 if (!entry)
1902 goto out;
1903
1904 ret = offset;
1905 if (entry->bitmap) {
1906 bitmap_clear_bits(ctl, entry, offset, bytes);
1907 if (!entry->bytes)
1908 free_bitmap(ctl, entry);
1909 } else {
1910 unlink_free_space(ctl, entry);
1911 entry->offset += bytes;
1912 entry->bytes -= bytes;
1913 if (!entry->bytes)
1914 kmem_cache_free(btrfs_free_space_cachep, entry);
1915 else
1916 link_free_space(ctl, entry);
1917 }
1918
1919 out:
1920 spin_unlock(&ctl->tree_lock);
1921
1922 return ret;
1923 }
1924
1925 /*
1926 * given a cluster, put all of its extents back into the free space
1927 * cache. If a block group is passed, this function will only free
1928 * a cluster that belongs to the passed block group.
1929 *
1930 * Otherwise, it'll get a reference on the block group pointed to by the
1931 * cluster and remove the cluster from it.
1932 */
1933 int btrfs_return_cluster_to_free_space(
1934 struct btrfs_block_group_cache *block_group,
1935 struct btrfs_free_cluster *cluster)
1936 {
1937 struct btrfs_free_space_ctl *ctl;
1938 int ret;
1939
1940 /* first, get a safe pointer to the block group */
1941 spin_lock(&cluster->lock);
1942 if (!block_group) {
1943 block_group = cluster->block_group;
1944 if (!block_group) {
1945 spin_unlock(&cluster->lock);
1946 return 0;
1947 }
1948 } else if (cluster->block_group != block_group) {
1949 /* someone else has already freed it don't redo their work */
1950 spin_unlock(&cluster->lock);
1951 return 0;
1952 }
1953 atomic_inc(&block_group->count);
1954 spin_unlock(&cluster->lock);
1955
1956 ctl = block_group->free_space_ctl;
1957
1958 /* now return any extents the cluster had on it */
1959 spin_lock(&ctl->tree_lock);
1960 ret = __btrfs_return_cluster_to_free_space(block_group, cluster);
1961 spin_unlock(&ctl->tree_lock);
1962
1963 /* finally drop our ref */
1964 btrfs_put_block_group(block_group);
1965 return ret;
1966 }
1967
1968 static u64 btrfs_alloc_from_bitmap(struct btrfs_block_group_cache *block_group,
1969 struct btrfs_free_cluster *cluster,
1970 struct btrfs_free_space *entry,
1971 u64 bytes, u64 min_start)
1972 {
1973 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
1974 int err;
1975 u64 search_start = cluster->window_start;
1976 u64 search_bytes = bytes;
1977 u64 ret = 0;
1978
1979 search_start = min_start;
1980 search_bytes = bytes;
1981
1982 err = search_bitmap(ctl, entry, &search_start, &search_bytes);
1983 if (err)
1984 return 0;
1985
1986 ret = search_start;
1987 bitmap_clear_bits(ctl, entry, ret, bytes);
1988
1989 return ret;
1990 }
1991
1992 /*
1993 * given a cluster, try to allocate 'bytes' from it, returns 0
1994 * if it couldn't find anything suitably large, or a logical disk offset
1995 * if things worked out
1996 */
1997 u64 btrfs_alloc_from_cluster(struct btrfs_block_group_cache *block_group,
1998 struct btrfs_free_cluster *cluster, u64 bytes,
1999 u64 min_start)
2000 {
2001 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2002 struct btrfs_free_space *entry = NULL;
2003 struct rb_node *node;
2004 u64 ret = 0;
2005
2006 spin_lock(&cluster->lock);
2007 if (bytes > cluster->max_size)
2008 goto out;
2009
2010 if (cluster->block_group != block_group)
2011 goto out;
2012
2013 node = rb_first(&cluster->root);
2014 if (!node)
2015 goto out;
2016
2017 entry = rb_entry(node, struct btrfs_free_space, offset_index);
2018 while(1) {
2019 if (entry->bytes < bytes ||
2020 (!entry->bitmap && entry->offset < min_start)) {
2021 node = rb_next(&entry->offset_index);
2022 if (!node)
2023 break;
2024 entry = rb_entry(node, struct btrfs_free_space,
2025 offset_index);
2026 continue;
2027 }
2028
2029 if (entry->bitmap) {
2030 ret = btrfs_alloc_from_bitmap(block_group,
2031 cluster, entry, bytes,
2032 min_start);
2033 if (ret == 0) {
2034 node = rb_next(&entry->offset_index);
2035 if (!node)
2036 break;
2037 entry = rb_entry(node, struct btrfs_free_space,
2038 offset_index);
2039 continue;
2040 }
2041 } else {
2042
2043 ret = entry->offset;
2044
2045 entry->offset += bytes;
2046 entry->bytes -= bytes;
2047 }
2048
2049 if (entry->bytes == 0)
2050 rb_erase(&entry->offset_index, &cluster->root);
2051 break;
2052 }
2053 out:
2054 spin_unlock(&cluster->lock);
2055
2056 if (!ret)
2057 return 0;
2058
2059 spin_lock(&ctl->tree_lock);
2060
2061 ctl->free_space -= bytes;
2062 if (entry->bytes == 0) {
2063 ctl->free_extents--;
2064 if (entry->bitmap) {
2065 kfree(entry->bitmap);
2066 ctl->total_bitmaps--;
2067 ctl->op->recalc_thresholds(ctl);
2068 }
2069 kmem_cache_free(btrfs_free_space_cachep, entry);
2070 }
2071
2072 spin_unlock(&ctl->tree_lock);
2073
2074 return ret;
2075 }
2076
2077 static int btrfs_bitmap_cluster(struct btrfs_block_group_cache *block_group,
2078 struct btrfs_free_space *entry,
2079 struct btrfs_free_cluster *cluster,
2080 u64 offset, u64 bytes, u64 min_bytes)
2081 {
2082 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2083 unsigned long next_zero;
2084 unsigned long i;
2085 unsigned long search_bits;
2086 unsigned long total_bits;
2087 unsigned long found_bits;
2088 unsigned long start = 0;
2089 unsigned long total_found = 0;
2090 int ret;
2091 bool found = false;
2092
2093 i = offset_to_bit(entry->offset, block_group->sectorsize,
2094 max_t(u64, offset, entry->offset));
2095 search_bits = bytes_to_bits(bytes, block_group->sectorsize);
2096 total_bits = bytes_to_bits(min_bytes, block_group->sectorsize);
2097
2098 again:
2099 found_bits = 0;
2100 for (i = find_next_bit(entry->bitmap, BITS_PER_BITMAP, i);
2101 i < BITS_PER_BITMAP;
2102 i = find_next_bit(entry->bitmap, BITS_PER_BITMAP, i + 1)) {
2103 next_zero = find_next_zero_bit(entry->bitmap,
2104 BITS_PER_BITMAP, i);
2105 if (next_zero - i >= search_bits) {
2106 found_bits = next_zero - i;
2107 break;
2108 }
2109 i = next_zero;
2110 }
2111
2112 if (!found_bits)
2113 return -ENOSPC;
2114
2115 if (!found) {
2116 start = i;
2117 found = true;
2118 }
2119
2120 total_found += found_bits;
2121
2122 if (cluster->max_size < found_bits * block_group->sectorsize)
2123 cluster->max_size = found_bits * block_group->sectorsize;
2124
2125 if (total_found < total_bits) {
2126 i = find_next_bit(entry->bitmap, BITS_PER_BITMAP, next_zero);
2127 if (i - start > total_bits * 2) {
2128 total_found = 0;
2129 cluster->max_size = 0;
2130 found = false;
2131 }
2132 goto again;
2133 }
2134
2135 cluster->window_start = start * block_group->sectorsize +
2136 entry->offset;
2137 rb_erase(&entry->offset_index, &ctl->free_space_offset);
2138 ret = tree_insert_offset(&cluster->root, entry->offset,
2139 &entry->offset_index, 1);
2140 BUG_ON(ret);
2141
2142 return 0;
2143 }
2144
2145 /*
2146 * This searches the block group for just extents to fill the cluster with.
2147 */
2148 static noinline int
2149 setup_cluster_no_bitmap(struct btrfs_block_group_cache *block_group,
2150 struct btrfs_free_cluster *cluster,
2151 struct list_head *bitmaps, u64 offset, u64 bytes,
2152 u64 min_bytes)
2153 {
2154 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2155 struct btrfs_free_space *first = NULL;
2156 struct btrfs_free_space *entry = NULL;
2157 struct btrfs_free_space *prev = NULL;
2158 struct btrfs_free_space *last;
2159 struct rb_node *node;
2160 u64 window_start;
2161 u64 window_free;
2162 u64 max_extent;
2163 u64 max_gap = 128 * 1024;
2164
2165 entry = tree_search_offset(ctl, offset, 0, 1);
2166 if (!entry)
2167 return -ENOSPC;
2168
2169 /*
2170 * We don't want bitmaps, so just move along until we find a normal
2171 * extent entry.
2172 */
2173 while (entry->bitmap) {
2174 if (list_empty(&entry->list))
2175 list_add_tail(&entry->list, bitmaps);
2176 node = rb_next(&entry->offset_index);
2177 if (!node)
2178 return -ENOSPC;
2179 entry = rb_entry(node, struct btrfs_free_space, offset_index);
2180 }
2181
2182 window_start = entry->offset;
2183 window_free = entry->bytes;
2184 max_extent = entry->bytes;
2185 first = entry;
2186 last = entry;
2187 prev = entry;
2188
2189 while (window_free <= min_bytes) {
2190 node = rb_next(&entry->offset_index);
2191 if (!node)
2192 return -ENOSPC;
2193 entry = rb_entry(node, struct btrfs_free_space, offset_index);
2194
2195 if (entry->bitmap) {
2196 if (list_empty(&entry->list))
2197 list_add_tail(&entry->list, bitmaps);
2198 continue;
2199 }
2200
2201 /*
2202 * we haven't filled the empty size and the window is
2203 * very large. reset and try again
2204 */
2205 if (entry->offset - (prev->offset + prev->bytes) > max_gap ||
2206 entry->offset - window_start > (min_bytes * 2)) {
2207 first = entry;
2208 window_start = entry->offset;
2209 window_free = entry->bytes;
2210 last = entry;
2211 max_extent = entry->bytes;
2212 } else {
2213 last = entry;
2214 window_free += entry->bytes;
2215 if (entry->bytes > max_extent)
2216 max_extent = entry->bytes;
2217 }
2218 prev = entry;
2219 }
2220
2221 cluster->window_start = first->offset;
2222
2223 node = &first->offset_index;
2224
2225 /*
2226 * now we've found our entries, pull them out of the free space
2227 * cache and put them into the cluster rbtree
2228 */
2229 do {
2230 int ret;
2231
2232 entry = rb_entry(node, struct btrfs_free_space, offset_index);
2233 node = rb_next(&entry->offset_index);
2234 if (entry->bitmap)
2235 continue;
2236
2237 rb_erase(&entry->offset_index, &ctl->free_space_offset);
2238 ret = tree_insert_offset(&cluster->root, entry->offset,
2239 &entry->offset_index, 0);
2240 BUG_ON(ret);
2241 } while (node && entry != last);
2242
2243 cluster->max_size = max_extent;
2244
2245 return 0;
2246 }
2247
2248 /*
2249 * This specifically looks for bitmaps that may work in the cluster, we assume
2250 * that we have already failed to find extents that will work.
2251 */
2252 static noinline int
2253 setup_cluster_bitmap(struct btrfs_block_group_cache *block_group,
2254 struct btrfs_free_cluster *cluster,
2255 struct list_head *bitmaps, u64 offset, u64 bytes,
2256 u64 min_bytes)
2257 {
2258 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2259 struct btrfs_free_space *entry;
2260 struct rb_node *node;
2261 int ret = -ENOSPC;
2262
2263 if (ctl->total_bitmaps == 0)
2264 return -ENOSPC;
2265
2266 /*
2267 * First check our cached list of bitmaps and see if there is an entry
2268 * here that will work.
2269 */
2270 list_for_each_entry(entry, bitmaps, list) {
2271 if (entry->bytes < min_bytes)
2272 continue;
2273 ret = btrfs_bitmap_cluster(block_group, entry, cluster, offset,
2274 bytes, min_bytes);
2275 if (!ret)
2276 return 0;
2277 }
2278
2279 /*
2280 * If we do have entries on our list and we are here then we didn't find
2281 * anything, so go ahead and get the next entry after the last entry in
2282 * this list and start the search from there.
2283 */
2284 if (!list_empty(bitmaps)) {
2285 entry = list_entry(bitmaps->prev, struct btrfs_free_space,
2286 list);
2287 node = rb_next(&entry->offset_index);
2288 if (!node)
2289 return -ENOSPC;
2290 entry = rb_entry(node, struct btrfs_free_space, offset_index);
2291 goto search;
2292 }
2293
2294 entry = tree_search_offset(ctl, offset_to_bitmap(ctl, offset), 0, 1);
2295 if (!entry)
2296 return -ENOSPC;
2297
2298 search:
2299 node = &entry->offset_index;
2300 do {
2301 entry = rb_entry(node, struct btrfs_free_space, offset_index);
2302 node = rb_next(&entry->offset_index);
2303 if (!entry->bitmap)
2304 continue;
2305 if (entry->bytes < min_bytes)
2306 continue;
2307 ret = btrfs_bitmap_cluster(block_group, entry, cluster, offset,
2308 bytes, min_bytes);
2309 } while (ret && node);
2310
2311 return ret;
2312 }
2313
2314 /*
2315 * here we try to find a cluster of blocks in a block group. The goal
2316 * is to find at least bytes free and up to empty_size + bytes free.
2317 * We might not find them all in one contiguous area.
2318 *
2319 * returns zero and sets up cluster if things worked out, otherwise
2320 * it returns -enospc
2321 */
2322 int btrfs_find_space_cluster(struct btrfs_trans_handle *trans,
2323 struct btrfs_root *root,
2324 struct btrfs_block_group_cache *block_group,
2325 struct btrfs_free_cluster *cluster,
2326 u64 offset, u64 bytes, u64 empty_size)
2327 {
2328 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2329 struct list_head bitmaps;
2330 struct btrfs_free_space *entry, *tmp;
2331 u64 min_bytes;
2332 int ret;
2333
2334 /* for metadata, allow allocates with more holes */
2335 if (btrfs_test_opt(root, SSD_SPREAD)) {
2336 min_bytes = bytes + empty_size;
2337 } else if (block_group->flags & BTRFS_BLOCK_GROUP_METADATA) {
2338 /*
2339 * we want to do larger allocations when we are
2340 * flushing out the delayed refs, it helps prevent
2341 * making more work as we go along.
2342 */
2343 if (trans->transaction->delayed_refs.flushing)
2344 min_bytes = max(bytes, (bytes + empty_size) >> 1);
2345 else
2346 min_bytes = max(bytes, (bytes + empty_size) >> 4);
2347 } else
2348 min_bytes = max(bytes, (bytes + empty_size) >> 2);
2349
2350 spin_lock(&ctl->tree_lock);
2351
2352 /*
2353 * If we know we don't have enough space to make a cluster don't even
2354 * bother doing all the work to try and find one.
2355 */
2356 if (ctl->free_space < min_bytes) {
2357 spin_unlock(&ctl->tree_lock);
2358 return -ENOSPC;
2359 }
2360
2361 spin_lock(&cluster->lock);
2362
2363 /* someone already found a cluster, hooray */
2364 if (cluster->block_group) {
2365 ret = 0;
2366 goto out;
2367 }
2368
2369 INIT_LIST_HEAD(&bitmaps);
2370 ret = setup_cluster_no_bitmap(block_group, cluster, &bitmaps, offset,
2371 bytes, min_bytes);
2372 if (ret)
2373 ret = setup_cluster_bitmap(block_group, cluster, &bitmaps,
2374 offset, bytes, min_bytes);
2375
2376 /* Clear our temporary list */
2377 list_for_each_entry_safe(entry, tmp, &bitmaps, list)
2378 list_del_init(&entry->list);
2379
2380 if (!ret) {
2381 atomic_inc(&block_group->count);
2382 list_add_tail(&cluster->block_group_list,
2383 &block_group->cluster_list);
2384 cluster->block_group = block_group;
2385 }
2386 out:
2387 spin_unlock(&cluster->lock);
2388 spin_unlock(&ctl->tree_lock);
2389
2390 return ret;
2391 }
2392
2393 /*
2394 * simple code to zero out a cluster
2395 */
2396 void btrfs_init_free_cluster(struct btrfs_free_cluster *cluster)
2397 {
2398 spin_lock_init(&cluster->lock);
2399 spin_lock_init(&cluster->refill_lock);
2400 cluster->root = RB_ROOT;
2401 cluster->max_size = 0;
2402 INIT_LIST_HEAD(&cluster->block_group_list);
2403 cluster->block_group = NULL;
2404 }
2405
2406 int btrfs_trim_block_group(struct btrfs_block_group_cache *block_group,
2407 u64 *trimmed, u64 start, u64 end, u64 minlen)
2408 {
2409 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2410 struct btrfs_free_space *entry = NULL;
2411 struct btrfs_fs_info *fs_info = block_group->fs_info;
2412 u64 bytes = 0;
2413 u64 actually_trimmed;
2414 int ret = 0;
2415
2416 *trimmed = 0;
2417
2418 while (start < end) {
2419 spin_lock(&ctl->tree_lock);
2420
2421 if (ctl->free_space < minlen) {
2422 spin_unlock(&ctl->tree_lock);
2423 break;
2424 }
2425
2426 entry = tree_search_offset(ctl, start, 0, 1);
2427 if (!entry)
2428 entry = tree_search_offset(ctl,
2429 offset_to_bitmap(ctl, start),
2430 1, 1);
2431
2432 if (!entry || entry->offset >= end) {
2433 spin_unlock(&ctl->tree_lock);
2434 break;
2435 }
2436
2437 if (entry->bitmap) {
2438 ret = search_bitmap(ctl, entry, &start, &bytes);
2439 if (!ret) {
2440 if (start >= end) {
2441 spin_unlock(&ctl->tree_lock);
2442 break;
2443 }
2444 bytes = min(bytes, end - start);
2445 bitmap_clear_bits(ctl, entry, start, bytes);
2446 if (entry->bytes == 0)
2447 free_bitmap(ctl, entry);
2448 } else {
2449 start = entry->offset + BITS_PER_BITMAP *
2450 block_group->sectorsize;
2451 spin_unlock(&ctl->tree_lock);
2452 ret = 0;
2453 continue;
2454 }
2455 } else {
2456 start = entry->offset;
2457 bytes = min(entry->bytes, end - start);
2458 unlink_free_space(ctl, entry);
2459 kmem_cache_free(btrfs_free_space_cachep, entry);
2460 }
2461
2462 spin_unlock(&ctl->tree_lock);
2463
2464 if (bytes >= minlen) {
2465 int update_ret;
2466 update_ret = btrfs_update_reserved_bytes(block_group,
2467 bytes, 1, 1);
2468
2469 ret = btrfs_error_discard_extent(fs_info->extent_root,
2470 start,
2471 bytes,
2472 &actually_trimmed);
2473
2474 btrfs_add_free_space(block_group, start, bytes);
2475 if (!update_ret)
2476 btrfs_update_reserved_bytes(block_group,
2477 bytes, 0, 1);
2478
2479 if (ret)
2480 break;
2481 *trimmed += actually_trimmed;
2482 }
2483 start += bytes;
2484 bytes = 0;
2485
2486 if (fatal_signal_pending(current)) {
2487 ret = -ERESTARTSYS;
2488 break;
2489 }
2490
2491 cond_resched();
2492 }
2493
2494 return ret;
2495 }
2496
2497 /*
2498 * Find the left-most item in the cache tree, and then return the
2499 * smallest inode number in the item.
2500 *
2501 * Note: the returned inode number may not be the smallest one in
2502 * the tree, if the left-most item is a bitmap.
2503 */
2504 u64 btrfs_find_ino_for_alloc(struct btrfs_root *fs_root)
2505 {
2506 struct btrfs_free_space_ctl *ctl = fs_root->free_ino_ctl;
2507 struct btrfs_free_space *entry = NULL;
2508 u64 ino = 0;
2509
2510 spin_lock(&ctl->tree_lock);
2511
2512 if (RB_EMPTY_ROOT(&ctl->free_space_offset))
2513 goto out;
2514
2515 entry = rb_entry(rb_first(&ctl->free_space_offset),
2516 struct btrfs_free_space, offset_index);
2517
2518 if (!entry->bitmap) {
2519 ino = entry->offset;
2520
2521 unlink_free_space(ctl, entry);
2522 entry->offset++;
2523 entry->bytes--;
2524 if (!entry->bytes)
2525 kmem_cache_free(btrfs_free_space_cachep, entry);
2526 else
2527 link_free_space(ctl, entry);
2528 } else {
2529 u64 offset = 0;
2530 u64 count = 1;
2531 int ret;
2532
2533 ret = search_bitmap(ctl, entry, &offset, &count);
2534 BUG_ON(ret);
2535
2536 ino = offset;
2537 bitmap_clear_bits(ctl, entry, offset, 1);
2538 if (entry->bytes == 0)
2539 free_bitmap(ctl, entry);
2540 }
2541 out:
2542 spin_unlock(&ctl->tree_lock);
2543
2544 return ino;
2545 }
2546
2547 struct inode *lookup_free_ino_inode(struct btrfs_root *root,
2548 struct btrfs_path *path)
2549 {
2550 struct inode *inode = NULL;
2551
2552 spin_lock(&root->cache_lock);
2553 if (root->cache_inode)
2554 inode = igrab(root->cache_inode);
2555 spin_unlock(&root->cache_lock);
2556 if (inode)
2557 return inode;
2558
2559 inode = __lookup_free_space_inode(root, path, 0);
2560 if (IS_ERR(inode))
2561 return inode;
2562
2563 spin_lock(&root->cache_lock);
2564 if (!btrfs_fs_closing(root->fs_info))
2565 root->cache_inode = igrab(inode);
2566 spin_unlock(&root->cache_lock);
2567
2568 return inode;
2569 }
2570
2571 int create_free_ino_inode(struct btrfs_root *root,
2572 struct btrfs_trans_handle *trans,
2573 struct btrfs_path *path)
2574 {
2575 return __create_free_space_inode(root, trans, path,
2576 BTRFS_FREE_INO_OBJECTID, 0);
2577 }
2578
2579 int load_free_ino_cache(struct btrfs_fs_info *fs_info, struct btrfs_root *root)
2580 {
2581 struct btrfs_free_space_ctl *ctl = root->free_ino_ctl;
2582 struct btrfs_path *path;
2583 struct inode *inode;
2584 int ret = 0;
2585 u64 root_gen = btrfs_root_generation(&root->root_item);
2586
2587 if (!btrfs_test_opt(root, INODE_MAP_CACHE))
2588 return 0;
2589
2590 /*
2591 * If we're unmounting then just return, since this does a search on the
2592 * normal root and not the commit root and we could deadlock.
2593 */
2594 if (btrfs_fs_closing(fs_info))
2595 return 0;
2596
2597 path = btrfs_alloc_path();
2598 if (!path)
2599 return 0;
2600
2601 inode = lookup_free_ino_inode(root, path);
2602 if (IS_ERR(inode))
2603 goto out;
2604
2605 if (root_gen != BTRFS_I(inode)->generation)
2606 goto out_put;
2607
2608 ret = __load_free_space_cache(root, inode, ctl, path, 0);
2609
2610 if (ret < 0)
2611 printk(KERN_ERR "btrfs: failed to load free ino cache for "
2612 "root %llu\n", root->root_key.objectid);
2613 out_put:
2614 iput(inode);
2615 out:
2616 btrfs_free_path(path);
2617 return ret;
2618 }
2619
2620 int btrfs_write_out_ino_cache(struct btrfs_root *root,
2621 struct btrfs_trans_handle *trans,
2622 struct btrfs_path *path)
2623 {
2624 struct btrfs_free_space_ctl *ctl = root->free_ino_ctl;
2625 struct inode *inode;
2626 int ret;
2627
2628 if (!btrfs_test_opt(root, INODE_MAP_CACHE))
2629 return 0;
2630
2631 inode = lookup_free_ino_inode(root, path);
2632 if (IS_ERR(inode))
2633 return 0;
2634
2635 ret = __btrfs_write_out_cache(root, inode, ctl, NULL, trans, path, 0);
2636 if (ret < 0)
2637 printk(KERN_ERR "btrfs: failed to write free ino cache "
2638 "for root %llu\n", root->root_key.objectid);
2639
2640 iput(inode);
2641 return ret;
2642 }
Linux 2.6 ibm-acpi/thinkpad-acpi driver git tree