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vmxnet3: Fix inconsistent LRO state after initialization
[linux-2.6/linux-mips.git] / fs / btrfs / free-space-cache.c
blobf561c953205bfb5dca0c53608c1770388a9db875
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
29 #define BITS_PER_BITMAP (PAGE_CACHE_SIZE * 8)
30 #define MAX_CACHE_BYTES_PER_GIG (32 * 1024)
31
32 static void recalculate_thresholds(struct btrfs_block_group_cache
33 *block_group);
34 static int link_free_space(struct btrfs_block_group_cache *block_group,
35 struct btrfs_free_space *info);
36
37 struct inode *lookup_free_space_inode(struct btrfs_root *root,
38 struct btrfs_block_group_cache
39 *block_group, struct btrfs_path *path)
40 {
41 struct btrfs_key key;
42 struct btrfs_key location;
43 struct btrfs_disk_key disk_key;
44 struct btrfs_free_space_header *header;
45 struct extent_buffer *leaf;
46 struct inode *inode = NULL;
47 int ret;
48
49 spin_lock(&block_group->lock);
50 if (block_group->inode)
51 inode = igrab(block_group->inode);
52 spin_unlock(&block_group->lock);
53 if (inode)
54 return inode;
55
56 key.objectid = BTRFS_FREE_SPACE_OBJECTID;
57 key.offset = block_group->key.objectid;
58 key.type = 0;
59
60 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
61 if (ret < 0)
62 return ERR_PTR(ret);
63 if (ret > 0) {
64 btrfs_release_path(root, path);
65 return ERR_PTR(-ENOENT);
66 }
67
68 leaf = path->nodes[0];
69 header = btrfs_item_ptr(leaf, path->slots[0],
70 struct btrfs_free_space_header);
71 btrfs_free_space_key(leaf, header, &disk_key);
72 btrfs_disk_key_to_cpu(&location, &disk_key);
73 btrfs_release_path(root, path);
74
75 inode = btrfs_iget(root->fs_info->sb, &location, root, NULL);
76 if (!inode)
77 return ERR_PTR(-ENOENT);
78 if (IS_ERR(inode))
79 return inode;
80 if (is_bad_inode(inode)) {
81 iput(inode);
82 return ERR_PTR(-ENOENT);
83 }
84
85 inode->i_mapping->flags &= ~__GFP_FS;
86
87 spin_lock(&block_group->lock);
88 if (!root->fs_info->closing) {
89 block_group->inode = igrab(inode);
90 block_group->iref = 1;
91 }
92 spin_unlock(&block_group->lock);
93
94 return inode;
95 }
96
97 int create_free_space_inode(struct btrfs_root *root,
98 struct btrfs_trans_handle *trans,
99 struct btrfs_block_group_cache *block_group,
100 struct btrfs_path *path)
101 {
102 struct btrfs_key key;
103 struct btrfs_disk_key disk_key;
104 struct btrfs_free_space_header *header;
105 struct btrfs_inode_item *inode_item;
106 struct extent_buffer *leaf;
107 u64 objectid;
108 int ret;
109
110 ret = btrfs_find_free_objectid(trans, root, 0, &objectid);
111 if (ret < 0)
112 return ret;
113
114 ret = btrfs_insert_empty_inode(trans, root, path, objectid);
115 if (ret)
116 return ret;
117
118 leaf = path->nodes[0];
119 inode_item = btrfs_item_ptr(leaf, path->slots[0],
120 struct btrfs_inode_item);
121 btrfs_item_key(leaf, &disk_key, path->slots[0]);
122 memset_extent_buffer(leaf, 0, (unsigned long)inode_item,
123 sizeof(*inode_item));
124 btrfs_set_inode_generation(leaf, inode_item, trans->transid);
125 btrfs_set_inode_size(leaf, inode_item, 0);
126 btrfs_set_inode_nbytes(leaf, inode_item, 0);
127 btrfs_set_inode_uid(leaf, inode_item, 0);
128 btrfs_set_inode_gid(leaf, inode_item, 0);
129 btrfs_set_inode_mode(leaf, inode_item, S_IFREG | 0600);
130 btrfs_set_inode_flags(leaf, inode_item, BTRFS_INODE_NOCOMPRESS |
131 BTRFS_INODE_PREALLOC | BTRFS_INODE_NODATASUM);
132 btrfs_set_inode_nlink(leaf, inode_item, 1);
133 btrfs_set_inode_transid(leaf, inode_item, trans->transid);
134 btrfs_set_inode_block_group(leaf, inode_item,
135 block_group->key.objectid);
136 btrfs_mark_buffer_dirty(leaf);
137 btrfs_release_path(root, path);
138
139 key.objectid = BTRFS_FREE_SPACE_OBJECTID;
140 key.offset = block_group->key.objectid;
141 key.type = 0;
142
143 ret = btrfs_insert_empty_item(trans, root, path, &key,
144 sizeof(struct btrfs_free_space_header));
145 if (ret < 0) {
146 btrfs_release_path(root, path);
147 return ret;
148 }
149 leaf = path->nodes[0];
150 header = btrfs_item_ptr(leaf, path->slots[0],
151 struct btrfs_free_space_header);
152 memset_extent_buffer(leaf, 0, (unsigned long)header, sizeof(*header));
153 btrfs_set_free_space_key(leaf, header, &disk_key);
154 btrfs_mark_buffer_dirty(leaf);
155 btrfs_release_path(root, path);
156
157 return 0;
158 }
159
160 int btrfs_truncate_free_space_cache(struct btrfs_root *root,
161 struct btrfs_trans_handle *trans,
162 struct btrfs_path *path,
163 struct inode *inode)
164 {
165 loff_t oldsize;
166 int ret = 0;
167
168 trans->block_rsv = root->orphan_block_rsv;
169 ret = btrfs_block_rsv_check(trans, root,
170 root->orphan_block_rsv,
171 0, 5);
172 if (ret)
173 return ret;
174
175 oldsize = i_size_read(inode);
176 btrfs_i_size_write(inode, 0);
177 truncate_pagecache(inode, oldsize, 0);
178
179 /*
180 * We don't need an orphan item because truncating the free space cache
181 * will never be split across transactions.
182 */
183 ret = btrfs_truncate_inode_items(trans, root, inode,
184 0, BTRFS_EXTENT_DATA_KEY);
185 if (ret) {
186 WARN_ON(1);
187 return ret;
188 }
189
190 return btrfs_update_inode(trans, root, inode);
191 }
192
193 static int readahead_cache(struct inode *inode)
194 {
195 struct file_ra_state *ra;
196 unsigned long last_index;
197
198 ra = kzalloc(sizeof(*ra), GFP_NOFS);
199 if (!ra)
200 return -ENOMEM;
201
202 file_ra_state_init(ra, inode->i_mapping);
203 last_index = (i_size_read(inode) - 1) >> PAGE_CACHE_SHIFT;
204
205 page_cache_sync_readahead(inode->i_mapping, ra, NULL, 0, last_index);
206
207 kfree(ra);
208
209 return 0;
210 }
211
212 int load_free_space_cache(struct btrfs_fs_info *fs_info,
213 struct btrfs_block_group_cache *block_group)
214 {
215 struct btrfs_root *root = fs_info->tree_root;
216 struct inode *inode;
217 struct btrfs_free_space_header *header;
218 struct extent_buffer *leaf;
219 struct page *page;
220 struct btrfs_path *path;
221 u32 *checksums = NULL, *crc;
222 char *disk_crcs = NULL;
223 struct btrfs_key key;
224 struct list_head bitmaps;
225 u64 num_entries;
226 u64 num_bitmaps;
227 u64 generation;
228 u64 used = btrfs_block_group_used(&block_group->item);
229 u32 cur_crc = ~(u32)0;
230 pgoff_t index = 0;
231 unsigned long first_page_offset;
232 int num_checksums;
233 int ret = 0;
234
235 /*
236 * If we're unmounting then just return, since this does a search on the
237 * normal root and not the commit root and we could deadlock.
238 */
239 smp_mb();
240 if (fs_info->closing)
241 return 0;
242
243 /*
244 * If this block group has been marked to be cleared for one reason or
245 * another then we can't trust the on disk cache, so just return.
246 */
247 spin_lock(&block_group->lock);
248 if (block_group->disk_cache_state != BTRFS_DC_WRITTEN) {
249 spin_unlock(&block_group->lock);
250 return 0;
251 }
252 spin_unlock(&block_group->lock);
253
254 INIT_LIST_HEAD(&bitmaps);
255
256 path = btrfs_alloc_path();
257 if (!path)
258 return 0;
259
260 inode = lookup_free_space_inode(root, block_group, path);
261 if (IS_ERR(inode)) {
262 btrfs_free_path(path);
263 return 0;
264 }
265
266 /* Nothing in the space cache, goodbye */
267 if (!i_size_read(inode)) {
268 btrfs_free_path(path);
269 goto out;
270 }
271
272 key.objectid = BTRFS_FREE_SPACE_OBJECTID;
273 key.offset = block_group->key.objectid;
274 key.type = 0;
275
276 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
277 if (ret) {
278 btrfs_free_path(path);
279 goto out;
280 }
281
282 leaf = path->nodes[0];
283 header = btrfs_item_ptr(leaf, path->slots[0],
284 struct btrfs_free_space_header);
285 num_entries = btrfs_free_space_entries(leaf, header);
286 num_bitmaps = btrfs_free_space_bitmaps(leaf, header);
287 generation = btrfs_free_space_generation(leaf, header);
288 btrfs_free_path(path);
289
290 if (BTRFS_I(inode)->generation != generation) {
291 printk(KERN_ERR "btrfs: free space inode generation (%llu) did"
292 " not match free space cache generation (%llu) for "
293 "block group %llu\n",
294 (unsigned long long)BTRFS_I(inode)->generation,
295 (unsigned long long)generation,
296 (unsigned long long)block_group->key.objectid);
297 goto free_cache;
298 }
299
300 if (!num_entries)
301 goto out;
302
303 /* Setup everything for doing checksumming */
304 num_checksums = i_size_read(inode) / PAGE_CACHE_SIZE;
305 checksums = crc = kzalloc(sizeof(u32) * num_checksums, GFP_NOFS);
306 if (!checksums)
307 goto out;
308 first_page_offset = (sizeof(u32) * num_checksums) + sizeof(u64);
309 disk_crcs = kzalloc(first_page_offset, GFP_NOFS);
310 if (!disk_crcs)
311 goto out;
312
313 ret = readahead_cache(inode);
314 if (ret) {
315 ret = 0;
316 goto out;
317 }
318
319 while (1) {
320 struct btrfs_free_space_entry *entry;
321 struct btrfs_free_space *e;
322 void *addr;
323 unsigned long offset = 0;
324 unsigned long start_offset = 0;
325 int need_loop = 0;
326
327 if (!num_entries && !num_bitmaps)
328 break;
329
330 if (index == 0) {
331 start_offset = first_page_offset;
332 offset = start_offset;
333 }
334
335 page = grab_cache_page(inode->i_mapping, index);
336 if (!page) {
337 ret = 0;
338 goto free_cache;
339 }
340
341 if (!PageUptodate(page)) {
342 btrfs_readpage(NULL, page);
343 lock_page(page);
344 if (!PageUptodate(page)) {
345 unlock_page(page);
346 page_cache_release(page);
347 printk(KERN_ERR "btrfs: error reading free "
348 "space cache: %llu\n",
349 (unsigned long long)
350 block_group->key.objectid);
351 goto free_cache;
352 }
353 }
354 addr = kmap(page);
355
356 if (index == 0) {
357 u64 *gen;
358
359 memcpy(disk_crcs, addr, first_page_offset);
360 gen = addr + (sizeof(u32) * num_checksums);
361 if (*gen != BTRFS_I(inode)->generation) {
362 printk(KERN_ERR "btrfs: space cache generation"
363 " (%llu) does not match inode (%llu) "
364 "for block group %llu\n",
365 (unsigned long long)*gen,
366 (unsigned long long)
367 BTRFS_I(inode)->generation,
368 (unsigned long long)
369 block_group->key.objectid);
370 kunmap(page);
371 unlock_page(page);
372 page_cache_release(page);
373 goto free_cache;
374 }
375 crc = (u32 *)disk_crcs;
376 }
377 entry = addr + start_offset;
378
379 /* First lets check our crc before we do anything fun */
380 cur_crc = ~(u32)0;
381 cur_crc = btrfs_csum_data(root, addr + start_offset, cur_crc,
382 PAGE_CACHE_SIZE - start_offset);
383 btrfs_csum_final(cur_crc, (char *)&cur_crc);
384 if (cur_crc != *crc) {
385 printk(KERN_ERR "btrfs: crc mismatch for page %lu in "
386 "block group %llu\n", index,
387 (unsigned long long)block_group->key.objectid);
388 kunmap(page);
389 unlock_page(page);
390 page_cache_release(page);
391 goto free_cache;
392 }
393 crc++;
394
395 while (1) {
396 if (!num_entries)
397 break;
398
399 need_loop = 1;
400 e = kmem_cache_zalloc(btrfs_free_space_cachep,
401 GFP_NOFS);
402 if (!e) {
403 kunmap(page);
404 unlock_page(page);
405 page_cache_release(page);
406 goto free_cache;
407 }
408
409 e->offset = le64_to_cpu(entry->offset);
410 e->bytes = le64_to_cpu(entry->bytes);
411 if (!e->bytes) {
412 kunmap(page);
413 kmem_cache_free(btrfs_free_space_cachep, e);
414 unlock_page(page);
415 page_cache_release(page);
416 goto free_cache;
417 }
418
419 if (entry->type == BTRFS_FREE_SPACE_EXTENT) {
420 spin_lock(&block_group->tree_lock);
421 ret = link_free_space(block_group, e);
422 spin_unlock(&block_group->tree_lock);
423 BUG_ON(ret);
424 } else {
425 e->bitmap = kzalloc(PAGE_CACHE_SIZE, GFP_NOFS);
426 if (!e->bitmap) {
427 kunmap(page);
428 kmem_cache_free(
429 btrfs_free_space_cachep, e);
430 unlock_page(page);
431 page_cache_release(page);
432 goto free_cache;
433 }
434 spin_lock(&block_group->tree_lock);
435 ret = link_free_space(block_group, e);
436 block_group->total_bitmaps++;
437 recalculate_thresholds(block_group);
438 spin_unlock(&block_group->tree_lock);
439 list_add_tail(&e->list, &bitmaps);
440 }
441
442 num_entries--;
443 offset += sizeof(struct btrfs_free_space_entry);
444 if (offset + sizeof(struct btrfs_free_space_entry) >=
445 PAGE_CACHE_SIZE)
446 break;
447 entry++;
448 }
449
450 /*
451 * We read an entry out of this page, we need to move on to the
452 * next page.
453 */
454 if (need_loop) {
455 kunmap(page);
456 goto next;
457 }
458
459 /*
460 * We add the bitmaps at the end of the entries in order that
461 * the bitmap entries are added to the cache.
462 */
463 e = list_entry(bitmaps.next, struct btrfs_free_space, list);
464 list_del_init(&e->list);
465 memcpy(e->bitmap, addr, PAGE_CACHE_SIZE);
466 kunmap(page);
467 num_bitmaps--;
468 next:
469 unlock_page(page);
470 page_cache_release(page);
471 index++;
472 }
473
474 spin_lock(&block_group->tree_lock);
475 if (block_group->free_space != (block_group->key.offset - used -
476 block_group->bytes_super)) {
477 spin_unlock(&block_group->tree_lock);
478 printk(KERN_ERR "block group %llu has an wrong amount of free "
479 "space\n", block_group->key.objectid);
480 ret = 0;
481 goto free_cache;
482 }
483 spin_unlock(&block_group->tree_lock);
484
485 ret = 1;
486 out:
487 kfree(checksums);
488 kfree(disk_crcs);
489 iput(inode);
490 return ret;
491
492 free_cache:
493 /* This cache is bogus, make sure it gets cleared */
494 spin_lock(&block_group->lock);
495 block_group->disk_cache_state = BTRFS_DC_CLEAR;
496 spin_unlock(&block_group->lock);
497 btrfs_remove_free_space_cache(block_group);
498 goto out;
499 }
500
501 int btrfs_write_out_cache(struct btrfs_root *root,
502 struct btrfs_trans_handle *trans,
503 struct btrfs_block_group_cache *block_group,
504 struct btrfs_path *path)
505 {
506 struct btrfs_free_space_header *header;
507 struct extent_buffer *leaf;
508 struct inode *inode;
509 struct rb_node *node;
510 struct list_head *pos, *n;
511 struct page *page;
512 struct extent_state *cached_state = NULL;
513 struct btrfs_free_cluster *cluster = NULL;
514 struct extent_io_tree *unpin = NULL;
515 struct list_head bitmap_list;
516 struct btrfs_key key;
517 u64 start, end, len;
518 u64 bytes = 0;
519 u32 *crc, *checksums;
520 pgoff_t index = 0, last_index = 0;
521 unsigned long first_page_offset;
522 int num_checksums;
523 int entries = 0;
524 int bitmaps = 0;
525 int ret = 0;
526 bool next_page = false;
527
528 root = root->fs_info->tree_root;
529
530 INIT_LIST_HEAD(&bitmap_list);
531
532 spin_lock(&block_group->lock);
533 if (block_group->disk_cache_state < BTRFS_DC_SETUP) {
534 spin_unlock(&block_group->lock);
535 return 0;
536 }
537 spin_unlock(&block_group->lock);
538
539 inode = lookup_free_space_inode(root, block_group, path);
540 if (IS_ERR(inode))
541 return 0;
542
543 if (!i_size_read(inode)) {
544 iput(inode);
545 return 0;
546 }
547
548 node = rb_first(&block_group->free_space_offset);
549 if (!node) {
550 iput(inode);
551 return 0;
552 }
553
554 last_index = (i_size_read(inode) - 1) >> PAGE_CACHE_SHIFT;
555 filemap_write_and_wait(inode->i_mapping);
556 btrfs_wait_ordered_range(inode, inode->i_size &
557 ~(root->sectorsize - 1), (u64)-1);
558
559 /* We need a checksum per page. */
560 num_checksums = i_size_read(inode) / PAGE_CACHE_SIZE;
561 crc = checksums = kzalloc(sizeof(u32) * num_checksums, GFP_NOFS);
562 if (!crc) {
563 iput(inode);
564 return 0;
565 }
566
567 /* Since the first page has all of our checksums and our generation we
568 * need to calculate the offset into the page that we can start writing
569 * our entries.
570 */
571 first_page_offset = (sizeof(u32) * num_checksums) + sizeof(u64);
572
573 /* Get the cluster for this block_group if it exists */
574 if (!list_empty(&block_group->cluster_list))
575 cluster = list_entry(block_group->cluster_list.next,
576 struct btrfs_free_cluster,
577 block_group_list);
578
579 /*
580 * We shouldn't have switched the pinned extents yet so this is the
581 * right one
582 */
583 unpin = root->fs_info->pinned_extents;
584
585 /*
586 * Lock all pages first so we can lock the extent safely.
587 *
588 * NOTE: Because we hold the ref the entire time we're going to write to
589 * the page find_get_page should never fail, so we don't do a check
590 * after find_get_page at this point. Just putting this here so people
591 * know and don't freak out.
592 */
593 while (index <= last_index) {
594 page = grab_cache_page(inode->i_mapping, index);
595 if (!page) {
596 pgoff_t i = 0;
597
598 while (i < index) {
599 page = find_get_page(inode->i_mapping, i);
600 unlock_page(page);
601 page_cache_release(page);
602 page_cache_release(page);
603 i++;
604 }
605 goto out_free;
606 }
607 index++;
608 }
609
610 index = 0;
611 lock_extent_bits(&BTRFS_I(inode)->io_tree, 0, i_size_read(inode) - 1,
612 0, &cached_state, GFP_NOFS);
613
614 /*
615 * When searching for pinned extents, we need to start at our start
616 * offset.
617 */
618 start = block_group->key.objectid;
619
620 /* Write out the extent entries */
621 do {
622 struct btrfs_free_space_entry *entry;
623 void *addr;
624 unsigned long offset = 0;
625 unsigned long start_offset = 0;
626
627 next_page = false;
628
629 if (index == 0) {
630 start_offset = first_page_offset;
631 offset = start_offset;
632 }
633
634 page = find_get_page(inode->i_mapping, index);
635
636 addr = kmap(page);
637 entry = addr + start_offset;
638
639 memset(addr, 0, PAGE_CACHE_SIZE);
640 while (node && !next_page) {
641 struct btrfs_free_space *e;
642
643 e = rb_entry(node, struct btrfs_free_space, offset_index);
644 entries++;
645
646 entry->offset = cpu_to_le64(e->offset);
647 entry->bytes = cpu_to_le64(e->bytes);
648 if (e->bitmap) {
649 entry->type = BTRFS_FREE_SPACE_BITMAP;
650 list_add_tail(&e->list, &bitmap_list);
651 bitmaps++;
652 } else {
653 entry->type = BTRFS_FREE_SPACE_EXTENT;
654 }
655 node = rb_next(node);
656 if (!node && cluster) {
657 node = rb_first(&cluster->root);
658 cluster = NULL;
659 }
660 offset += sizeof(struct btrfs_free_space_entry);
661 if (offset + sizeof(struct btrfs_free_space_entry) >=
662 PAGE_CACHE_SIZE)
663 next_page = true;
664 entry++;
665 }
666
667 /*
668 * We want to add any pinned extents to our free space cache
669 * so we don't leak the space
670 */
671 while (!next_page && (start < block_group->key.objectid +
672 block_group->key.offset)) {
673 ret = find_first_extent_bit(unpin, start, &start, &end,
674 EXTENT_DIRTY);
675 if (ret) {
676 ret = 0;
677 break;
678 }
679
680 /* This pinned extent is out of our range */
681 if (start >= block_group->key.objectid +
682 block_group->key.offset)
683 break;
684
685 len = block_group->key.objectid +
686 block_group->key.offset - start;
687 len = min(len, end + 1 - start);
688
689 entries++;
690 entry->offset = cpu_to_le64(start);
691 entry->bytes = cpu_to_le64(len);
692 entry->type = BTRFS_FREE_SPACE_EXTENT;
693
694 start = end + 1;
695 offset += sizeof(struct btrfs_free_space_entry);
696 if (offset + sizeof(struct btrfs_free_space_entry) >=
697 PAGE_CACHE_SIZE)
698 next_page = true;
699 entry++;
700 }
701 *crc = ~(u32)0;
702 *crc = btrfs_csum_data(root, addr + start_offset, *crc,
703 PAGE_CACHE_SIZE - start_offset);
704 kunmap(page);
705
706 btrfs_csum_final(*crc, (char *)crc);
707 crc++;
708
709 bytes += PAGE_CACHE_SIZE;
710
711 ClearPageChecked(page);
712 set_page_extent_mapped(page);
713 SetPageUptodate(page);
714 set_page_dirty(page);
715
716 /*
717 * We need to release our reference we got for grab_cache_page,
718 * except for the first page which will hold our checksums, we
719 * do that below.
720 */
721 if (index != 0) {
722 unlock_page(page);
723 page_cache_release(page);
724 }
725
726 page_cache_release(page);
727
728 index++;
729 } while (node || next_page);
730
731 /* Write out the bitmaps */
732 list_for_each_safe(pos, n, &bitmap_list) {
733 void *addr;
734 struct btrfs_free_space *entry =
735 list_entry(pos, struct btrfs_free_space, list);
736
737 page = find_get_page(inode->i_mapping, index);
738
739 addr = kmap(page);
740 memcpy(addr, entry->bitmap, PAGE_CACHE_SIZE);
741 *crc = ~(u32)0;
742 *crc = btrfs_csum_data(root, addr, *crc, PAGE_CACHE_SIZE);
743 kunmap(page);
744 btrfs_csum_final(*crc, (char *)crc);
745 crc++;
746 bytes += PAGE_CACHE_SIZE;
747
748 ClearPageChecked(page);
749 set_page_extent_mapped(page);
750 SetPageUptodate(page);
751 set_page_dirty(page);
752 unlock_page(page);
753 page_cache_release(page);
754 page_cache_release(page);
755 list_del_init(&entry->list);
756 index++;
757 }
758
759 /* Zero out the rest of the pages just to make sure */
760 while (index <= last_index) {
761 void *addr;
762
763 page = find_get_page(inode->i_mapping, index);
764
765 addr = kmap(page);
766 memset(addr, 0, PAGE_CACHE_SIZE);
767 kunmap(page);
768 ClearPageChecked(page);
769 set_page_extent_mapped(page);
770 SetPageUptodate(page);
771 set_page_dirty(page);
772 unlock_page(page);
773 page_cache_release(page);
774 page_cache_release(page);
775 bytes += PAGE_CACHE_SIZE;
776 index++;
777 }
778
779 btrfs_set_extent_delalloc(inode, 0, bytes - 1, &cached_state);
780
781 /* Write the checksums and trans id to the first page */
782 {
783 void *addr;
784 u64 *gen;
785
786 page = find_get_page(inode->i_mapping, 0);
787
788 addr = kmap(page);
789 memcpy(addr, checksums, sizeof(u32) * num_checksums);
790 gen = addr + (sizeof(u32) * num_checksums);
791 *gen = trans->transid;
792 kunmap(page);
793 ClearPageChecked(page);
794 set_page_extent_mapped(page);
795 SetPageUptodate(page);
796 set_page_dirty(page);
797 unlock_page(page);
798 page_cache_release(page);
799 page_cache_release(page);
800 }
801 BTRFS_I(inode)->generation = trans->transid;
802
803 unlock_extent_cached(&BTRFS_I(inode)->io_tree, 0,
804 i_size_read(inode) - 1, &cached_state, GFP_NOFS);
805
806 filemap_write_and_wait(inode->i_mapping);
807
808 key.objectid = BTRFS_FREE_SPACE_OBJECTID;
809 key.offset = block_group->key.objectid;
810 key.type = 0;
811
812 ret = btrfs_search_slot(trans, root, &key, path, 1, 1);
813 if (ret < 0) {
814 ret = 0;
815 clear_extent_bit(&BTRFS_I(inode)->io_tree, 0, bytes - 1,
816 EXTENT_DIRTY | EXTENT_DELALLOC |
817 EXTENT_DO_ACCOUNTING, 0, 0, NULL, GFP_NOFS);
818 goto out_free;
819 }
820 leaf = path->nodes[0];
821 if (ret > 0) {
822 struct btrfs_key found_key;
823 BUG_ON(!path->slots[0]);
824 path->slots[0]--;
825 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
826 if (found_key.objectid != BTRFS_FREE_SPACE_OBJECTID ||
827 found_key.offset != block_group->key.objectid) {
828 ret = 0;
829 clear_extent_bit(&BTRFS_I(inode)->io_tree, 0, bytes - 1,
830 EXTENT_DIRTY | EXTENT_DELALLOC |
831 EXTENT_DO_ACCOUNTING, 0, 0, NULL,
832 GFP_NOFS);
833 btrfs_release_path(root, path);
834 goto out_free;
835 }
836 }
837 header = btrfs_item_ptr(leaf, path->slots[0],
838 struct btrfs_free_space_header);
839 btrfs_set_free_space_entries(leaf, header, entries);
840 btrfs_set_free_space_bitmaps(leaf, header, bitmaps);
841 btrfs_set_free_space_generation(leaf, header, trans->transid);
842 btrfs_mark_buffer_dirty(leaf);
843 btrfs_release_path(root, path);
844
845 ret = 1;
846
847 out_free:
848 if (ret == 0) {
849 invalidate_inode_pages2_range(inode->i_mapping, 0, index);
850 spin_lock(&block_group->lock);
851 block_group->disk_cache_state = BTRFS_DC_ERROR;
852 spin_unlock(&block_group->lock);
853 BTRFS_I(inode)->generation = 0;
854 }
855 kfree(checksums);
856 btrfs_update_inode(trans, root, inode);
857 iput(inode);
858 return ret;
859 }
860
861 static inline unsigned long offset_to_bit(u64 bitmap_start, u64 sectorsize,
862 u64 offset)
863 {
864 BUG_ON(offset < bitmap_start);
865 offset -= bitmap_start;
866 return (unsigned long)(div64_u64(offset, sectorsize));
867 }
868
869 static inline unsigned long bytes_to_bits(u64 bytes, u64 sectorsize)
870 {
871 return (unsigned long)(div64_u64(bytes, sectorsize));
872 }
873
874 static inline u64 offset_to_bitmap(struct btrfs_block_group_cache *block_group,
875 u64 offset)
876 {
877 u64 bitmap_start;
878 u64 bytes_per_bitmap;
879
880 bytes_per_bitmap = BITS_PER_BITMAP * block_group->sectorsize;
881 bitmap_start = offset - block_group->key.objectid;
882 bitmap_start = div64_u64(bitmap_start, bytes_per_bitmap);
883 bitmap_start *= bytes_per_bitmap;
884 bitmap_start += block_group->key.objectid;
885
886 return bitmap_start;
887 }
888
889 static int tree_insert_offset(struct rb_root *root, u64 offset,
890 struct rb_node *node, int bitmap)
891 {
892 struct rb_node **p = &root->rb_node;
893 struct rb_node *parent = NULL;
894 struct btrfs_free_space *info;
895
896 while (*p) {
897 parent = *p;
898 info = rb_entry(parent, struct btrfs_free_space, offset_index);
899
900 if (offset < info->offset) {
901 p = &(*p)->rb_left;
902 } else if (offset > info->offset) {
903 p = &(*p)->rb_right;
904 } else {
905 /*
906 * we could have a bitmap entry and an extent entry
907 * share the same offset. If this is the case, we want
908 * the extent entry to always be found first if we do a
909 * linear search through the tree, since we want to have
910 * the quickest allocation time, and allocating from an
911 * extent is faster than allocating from a bitmap. So
912 * if we're inserting a bitmap and we find an entry at
913 * this offset, we want to go right, or after this entry
914 * logically. If we are inserting an extent and we've
915 * found a bitmap, we want to go left, or before
916 * logically.
917 */
918 if (bitmap) {
919 WARN_ON(info->bitmap);
920 p = &(*p)->rb_right;
921 } else {
922 WARN_ON(!info->bitmap);
923 p = &(*p)->rb_left;
924 }
925 }
926 }
927
928 rb_link_node(node, parent, p);
929 rb_insert_color(node, root);
930
931 return 0;
932 }
933
934 /*
935 * searches the tree for the given offset.
936 *
937 * fuzzy - If this is set, then we are trying to make an allocation, and we just
938 * want a section that has at least bytes size and comes at or after the given
939 * offset.
940 */
941 static struct btrfs_free_space *
942 tree_search_offset(struct btrfs_block_group_cache *block_group,
943 u64 offset, int bitmap_only, int fuzzy)
944 {
945 struct rb_node *n = block_group->free_space_offset.rb_node;
946 struct btrfs_free_space *entry, *prev = NULL;
947
948 /* find entry that is closest to the 'offset' */
949 while (1) {
950 if (!n) {
951 entry = NULL;
952 break;
953 }
954
955 entry = rb_entry(n, struct btrfs_free_space, offset_index);
956 prev = entry;
957
958 if (offset < entry->offset)
959 n = n->rb_left;
960 else if (offset > entry->offset)
961 n = n->rb_right;
962 else
963 break;
964 }
965
966 if (bitmap_only) {
967 if (!entry)
968 return NULL;
969 if (entry->bitmap)
970 return entry;
971
972 /*
973 * bitmap entry and extent entry may share same offset,
974 * in that case, bitmap entry comes after extent entry.
975 */
976 n = rb_next(n);
977 if (!n)
978 return NULL;
979 entry = rb_entry(n, struct btrfs_free_space, offset_index);
980 if (entry->offset != offset)
981 return NULL;
982
983 WARN_ON(!entry->bitmap);
984 return entry;
985 } else if (entry) {
986 if (entry->bitmap) {
987 /*
988 * if previous extent entry covers the offset,
989 * we should return it instead of the bitmap entry
990 */
991 n = &entry->offset_index;
992 while (1) {
993 n = rb_prev(n);
994 if (!n)
995 break;
996 prev = rb_entry(n, struct btrfs_free_space,
997 offset_index);
998 if (!prev->bitmap) {
999 if (prev->offset + prev->bytes > offset)
1000 entry = prev;
1001 break;
1002 }
1003 }
1004 }
1005 return entry;
1006 }
1007
1008 if (!prev)
1009 return NULL;
1010
1011 /* find last entry before the 'offset' */
1012 entry = prev;
1013 if (entry->offset > offset) {
1014 n = rb_prev(&entry->offset_index);
1015 if (n) {
1016 entry = rb_entry(n, struct btrfs_free_space,
1017 offset_index);
1018 BUG_ON(entry->offset > offset);
1019 } else {
1020 if (fuzzy)
1021 return entry;
1022 else
1023 return NULL;
1024 }
1025 }
1026
1027 if (entry->bitmap) {
1028 n = &entry->offset_index;
1029 while (1) {
1030 n = rb_prev(n);
1031 if (!n)
1032 break;
1033 prev = rb_entry(n, struct btrfs_free_space,
1034 offset_index);
1035 if (!prev->bitmap) {
1036 if (prev->offset + prev->bytes > offset)
1037 return prev;
1038 break;
1039 }
1040 }
1041 if (entry->offset + BITS_PER_BITMAP *
1042 block_group->sectorsize > offset)
1043 return entry;
1044 } else if (entry->offset + entry->bytes > offset)
1045 return entry;
1046
1047 if (!fuzzy)
1048 return NULL;
1049
1050 while (1) {
1051 if (entry->bitmap) {
1052 if (entry->offset + BITS_PER_BITMAP *
1053 block_group->sectorsize > offset)
1054 break;
1055 } else {
1056 if (entry->offset + entry->bytes > offset)
1057 break;
1058 }
1059
1060 n = rb_next(&entry->offset_index);
1061 if (!n)
1062 return NULL;
1063 entry = rb_entry(n, struct btrfs_free_space, offset_index);
1064 }
1065 return entry;
1066 }
1067
1068 static inline void
1069 __unlink_free_space(struct btrfs_block_group_cache *block_group,
1070 struct btrfs_free_space *info)
1071 {
1072 rb_erase(&info->offset_index, &block_group->free_space_offset);
1073 block_group->free_extents--;
1074 }
1075
1076 static void unlink_free_space(struct btrfs_block_group_cache *block_group,
1077 struct btrfs_free_space *info)
1078 {
1079 __unlink_free_space(block_group, info);
1080 block_group->free_space -= info->bytes;
1081 }
1082
1083 static int link_free_space(struct btrfs_block_group_cache *block_group,
1084 struct btrfs_free_space *info)
1085 {
1086 int ret = 0;
1087
1088 BUG_ON(!info->bitmap && !info->bytes);
1089 ret = tree_insert_offset(&block_group->free_space_offset, info->offset,
1090 &info->offset_index, (info->bitmap != NULL));
1091 if (ret)
1092 return ret;
1093
1094 block_group->free_space += info->bytes;
1095 block_group->free_extents++;
1096 return ret;
1097 }
1098
1099 static void recalculate_thresholds(struct btrfs_block_group_cache *block_group)
1100 {
1101 u64 max_bytes;
1102 u64 bitmap_bytes;
1103 u64 extent_bytes;
1104 u64 size = block_group->key.offset;
1105
1106 /*
1107 * The goal is to keep the total amount of memory used per 1gb of space
1108 * at or below 32k, so we need to adjust how much memory we allow to be
1109 * used by extent based free space tracking
1110 */
1111 if (size < 1024 * 1024 * 1024)
1112 max_bytes = MAX_CACHE_BYTES_PER_GIG;
1113 else
1114 max_bytes = MAX_CACHE_BYTES_PER_GIG *
1115 div64_u64(size, 1024 * 1024 * 1024);
1116
1117 /*
1118 * we want to account for 1 more bitmap than what we have so we can make
1119 * sure we don't go over our overall goal of MAX_CACHE_BYTES_PER_GIG as
1120 * we add more bitmaps.
1121 */
1122 bitmap_bytes = (block_group->total_bitmaps + 1) * PAGE_CACHE_SIZE;
1123
1124 if (bitmap_bytes >= max_bytes) {
1125 block_group->extents_thresh = 0;
1126 return;
1127 }
1128
1129 /*
1130 * we want the extent entry threshold to always be at most 1/2 the maxw
1131 * bytes we can have, or whatever is less than that.
1132 */
1133 extent_bytes = max_bytes - bitmap_bytes;
1134 extent_bytes = min_t(u64, extent_bytes, div64_u64(max_bytes, 2));
1135
1136 block_group->extents_thresh =
1137 div64_u64(extent_bytes, (sizeof(struct btrfs_free_space)));
1138 }
1139
1140 static void bitmap_clear_bits(struct btrfs_block_group_cache *block_group,
1141 struct btrfs_free_space *info, u64 offset,
1142 u64 bytes)
1143 {
1144 unsigned long start, end;
1145 unsigned long i;
1146
1147 start = offset_to_bit(info->offset, block_group->sectorsize, offset);
1148 end = start + bytes_to_bits(bytes, block_group->sectorsize);
1149 BUG_ON(end > BITS_PER_BITMAP);
1150
1151 for (i = start; i < end; i++)
1152 clear_bit(i, info->bitmap);
1153
1154 info->bytes -= bytes;
1155 block_group->free_space -= bytes;
1156 }
1157
1158 static void bitmap_set_bits(struct btrfs_block_group_cache *block_group,
1159 struct btrfs_free_space *info, u64 offset,
1160 u64 bytes)
1161 {
1162 unsigned long start, end;
1163 unsigned long i;
1164
1165 start = offset_to_bit(info->offset, block_group->sectorsize, offset);
1166 end = start + bytes_to_bits(bytes, block_group->sectorsize);
1167 BUG_ON(end > BITS_PER_BITMAP);
1168
1169 for (i = start; i < end; i++)
1170 set_bit(i, info->bitmap);
1171
1172 info->bytes += bytes;
1173 block_group->free_space += bytes;
1174 }
1175
1176 static int search_bitmap(struct btrfs_block_group_cache *block_group,
1177 struct btrfs_free_space *bitmap_info, u64 *offset,
1178 u64 *bytes)
1179 {
1180 unsigned long found_bits = 0;
1181 unsigned long bits, i;
1182 unsigned long next_zero;
1183
1184 i = offset_to_bit(bitmap_info->offset, block_group->sectorsize,
1185 max_t(u64, *offset, bitmap_info->offset));
1186 bits = bytes_to_bits(*bytes, block_group->sectorsize);
1187
1188 for (i = find_next_bit(bitmap_info->bitmap, BITS_PER_BITMAP, i);
1189 i < BITS_PER_BITMAP;
1190 i = find_next_bit(bitmap_info->bitmap, BITS_PER_BITMAP, i + 1)) {
1191 next_zero = find_next_zero_bit(bitmap_info->bitmap,
1192 BITS_PER_BITMAP, i);
1193 if ((next_zero - i) >= bits) {
1194 found_bits = next_zero - i;
1195 break;
1196 }
1197 i = next_zero;
1198 }
1199
1200 if (found_bits) {
1201 *offset = (u64)(i * block_group->sectorsize) +
1202 bitmap_info->offset;
1203 *bytes = (u64)(found_bits) * block_group->sectorsize;
1204 return 0;
1205 }
1206
1207 return -1;
1208 }
1209
1210 static struct btrfs_free_space *find_free_space(struct btrfs_block_group_cache
1211 *block_group, u64 *offset,
1212 u64 *bytes, int debug)
1213 {
1214 struct btrfs_free_space *entry;
1215 struct rb_node *node;
1216 int ret;
1217
1218 if (!block_group->free_space_offset.rb_node)
1219 return NULL;
1220
1221 entry = tree_search_offset(block_group,
1222 offset_to_bitmap(block_group, *offset),
1223 0, 1);
1224 if (!entry)
1225 return NULL;
1226
1227 for (node = &entry->offset_index; node; node = rb_next(node)) {
1228 entry = rb_entry(node, struct btrfs_free_space, offset_index);
1229 if (entry->bytes < *bytes)
1230 continue;
1231
1232 if (entry->bitmap) {
1233 ret = search_bitmap(block_group, entry, offset, bytes);
1234 if (!ret)
1235 return entry;
1236 continue;
1237 }
1238
1239 *offset = entry->offset;
1240 *bytes = entry->bytes;
1241 return entry;
1242 }
1243
1244 return NULL;
1245 }
1246
1247 static void add_new_bitmap(struct btrfs_block_group_cache *block_group,
1248 struct btrfs_free_space *info, u64 offset)
1249 {
1250 u64 bytes_per_bg = BITS_PER_BITMAP * block_group->sectorsize;
1251 int max_bitmaps = (int)div64_u64(block_group->key.offset +
1252 bytes_per_bg - 1, bytes_per_bg);
1253 BUG_ON(block_group->total_bitmaps >= max_bitmaps);
1254
1255 info->offset = offset_to_bitmap(block_group, offset);
1256 info->bytes = 0;
1257 link_free_space(block_group, info);
1258 block_group->total_bitmaps++;
1259
1260 recalculate_thresholds(block_group);
1261 }
1262
1263 static void free_bitmap(struct btrfs_block_group_cache *block_group,
1264 struct btrfs_free_space *bitmap_info)
1265 {
1266 unlink_free_space(block_group, bitmap_info);
1267 kfree(bitmap_info->bitmap);
1268 kmem_cache_free(btrfs_free_space_cachep, bitmap_info);
1269 block_group->total_bitmaps--;
1270 recalculate_thresholds(block_group);
1271 }
1272
1273 static noinline int remove_from_bitmap(struct btrfs_block_group_cache *block_group,
1274 struct btrfs_free_space *bitmap_info,
1275 u64 *offset, u64 *bytes)
1276 {
1277 u64 end;
1278 u64 search_start, search_bytes;
1279 int ret;
1280
1281 again:
1282 end = bitmap_info->offset +
1283 (u64)(BITS_PER_BITMAP * block_group->sectorsize) - 1;
1284
1285 /*
1286 * XXX - this can go away after a few releases.
1287 *
1288 * since the only user of btrfs_remove_free_space is the tree logging
1289 * stuff, and the only way to test that is under crash conditions, we
1290 * want to have this debug stuff here just in case somethings not
1291 * working. Search the bitmap for the space we are trying to use to
1292 * make sure its actually there. If its not there then we need to stop
1293 * because something has gone wrong.
1294 */
1295 search_start = *offset;
1296 search_bytes = *bytes;
1297 search_bytes = min(search_bytes, end - search_start + 1);
1298 ret = search_bitmap(block_group, bitmap_info, &search_start,
1299 &search_bytes);
1300 BUG_ON(ret < 0 || search_start != *offset);
1301
1302 if (*offset > bitmap_info->offset && *offset + *bytes > end) {
1303 bitmap_clear_bits(block_group, bitmap_info, *offset,
1304 end - *offset + 1);
1305 *bytes -= end - *offset + 1;
1306 *offset = end + 1;
1307 } else if (*offset >= bitmap_info->offset && *offset + *bytes <= end) {
1308 bitmap_clear_bits(block_group, bitmap_info, *offset, *bytes);
1309 *bytes = 0;
1310 }
1311
1312 if (*bytes) {
1313 struct rb_node *next = rb_next(&bitmap_info->offset_index);
1314 if (!bitmap_info->bytes)
1315 free_bitmap(block_group, bitmap_info);
1316
1317 /*
1318 * no entry after this bitmap, but we still have bytes to
1319 * remove, so something has gone wrong.
1320 */
1321 if (!next)
1322 return -EINVAL;
1323
1324 bitmap_info = rb_entry(next, struct btrfs_free_space,
1325 offset_index);
1326
1327 /*
1328 * if the next entry isn't a bitmap we need to return to let the
1329 * extent stuff do its work.
1330 */
1331 if (!bitmap_info->bitmap)
1332 return -EAGAIN;
1333
1334 /*
1335 * Ok the next item is a bitmap, but it may not actually hold
1336 * the information for the rest of this free space stuff, so
1337 * look for it, and if we don't find it return so we can try
1338 * everything over again.
1339 */
1340 search_start = *offset;
1341 search_bytes = *bytes;
1342 ret = search_bitmap(block_group, bitmap_info, &search_start,
1343 &search_bytes);
1344 if (ret < 0 || search_start != *offset)
1345 return -EAGAIN;
1346
1347 goto again;
1348 } else if (!bitmap_info->bytes)
1349 free_bitmap(block_group, bitmap_info);
1350
1351 return 0;
1352 }
1353
1354 static int insert_into_bitmap(struct btrfs_block_group_cache *block_group,
1355 struct btrfs_free_space *info)
1356 {
1357 struct btrfs_free_space *bitmap_info;
1358 int added = 0;
1359 u64 bytes, offset, end;
1360 int ret;
1361
1362 /*
1363 * If we are below the extents threshold then we can add this as an
1364 * extent, and don't have to deal with the bitmap
1365 */
1366 if (block_group->free_extents < block_group->extents_thresh) {
1367 /*
1368 * If this block group has some small extents we don't want to
1369 * use up all of our free slots in the cache with them, we want
1370 * to reserve them to larger extents, however if we have plent
1371 * of cache left then go ahead an dadd them, no sense in adding
1372 * the overhead of a bitmap if we don't have to.
1373 */
1374 if (info->bytes <= block_group->sectorsize * 4) {
1375 if (block_group->free_extents * 2 <=
1376 block_group->extents_thresh)
1377 return 0;
1378 } else {
1379 return 0;
1380 }
1381 }
1382
1383 /*
1384 * some block groups are so tiny they can't be enveloped by a bitmap, so
1385 * don't even bother to create a bitmap for this
1386 */
1387 if (BITS_PER_BITMAP * block_group->sectorsize >
1388 block_group->key.offset)
1389 return 0;
1390
1391 bytes = info->bytes;
1392 offset = info->offset;
1393
1394 again:
1395 bitmap_info = tree_search_offset(block_group,
1396 offset_to_bitmap(block_group, offset),
1397 1, 0);
1398 if (!bitmap_info) {
1399 BUG_ON(added);
1400 goto new_bitmap;
1401 }
1402
1403 end = bitmap_info->offset +
1404 (u64)(BITS_PER_BITMAP * block_group->sectorsize);
1405
1406 if (offset >= bitmap_info->offset && offset + bytes > end) {
1407 bitmap_set_bits(block_group, bitmap_info, offset,
1408 end - offset);
1409 bytes -= end - offset;
1410 offset = end;
1411 added = 0;
1412 } else if (offset >= bitmap_info->offset && offset + bytes <= end) {
1413 bitmap_set_bits(block_group, bitmap_info, offset, bytes);
1414 bytes = 0;
1415 } else {
1416 BUG();
1417 }
1418
1419 if (!bytes) {
1420 ret = 1;
1421 goto out;
1422 } else
1423 goto again;
1424
1425 new_bitmap:
1426 if (info && info->bitmap) {
1427 add_new_bitmap(block_group, info, offset);
1428 added = 1;
1429 info = NULL;
1430 goto again;
1431 } else {
1432 spin_unlock(&block_group->tree_lock);
1433
1434 /* no pre-allocated info, allocate a new one */
1435 if (!info) {
1436 info = kmem_cache_zalloc(btrfs_free_space_cachep,
1437 GFP_NOFS);
1438 if (!info) {
1439 spin_lock(&block_group->tree_lock);
1440 ret = -ENOMEM;
1441 goto out;
1442 }
1443 }
1444
1445 /* allocate the bitmap */
1446 info->bitmap = kzalloc(PAGE_CACHE_SIZE, GFP_NOFS);
1447 spin_lock(&block_group->tree_lock);
1448 if (!info->bitmap) {
1449 ret = -ENOMEM;
1450 goto out;
1451 }
1452 goto again;
1453 }
1454
1455 out:
1456 if (info) {
1457 if (info->bitmap)
1458 kfree(info->bitmap);
1459 kmem_cache_free(btrfs_free_space_cachep, info);
1460 }
1461
1462 return ret;
1463 }
1464
1465 bool try_merge_free_space(struct btrfs_block_group_cache *block_group,
1466 struct btrfs_free_space *info, bool update_stat)
1467 {
1468 struct btrfs_free_space *left_info;
1469 struct btrfs_free_space *right_info;
1470 bool merged = false;
1471 u64 offset = info->offset;
1472 u64 bytes = info->bytes;
1473
1474 /*
1475 * first we want to see if there is free space adjacent to the range we
1476 * are adding, if there is remove that struct and add a new one to
1477 * cover the entire range
1478 */
1479 right_info = tree_search_offset(block_group, offset + bytes, 0, 0);
1480 if (right_info && rb_prev(&right_info->offset_index))
1481 left_info = rb_entry(rb_prev(&right_info->offset_index),
1482 struct btrfs_free_space, offset_index);
1483 else
1484 left_info = tree_search_offset(block_group, offset - 1, 0, 0);
1485
1486 if (right_info && !right_info->bitmap) {
1487 if (update_stat)
1488 unlink_free_space(block_group, right_info);
1489 else
1490 __unlink_free_space(block_group, right_info);
1491 info->bytes += right_info->bytes;
1492 kmem_cache_free(btrfs_free_space_cachep, right_info);
1493 merged = true;
1494 }
1495
1496 if (left_info && !left_info->bitmap &&
1497 left_info->offset + left_info->bytes == offset) {
1498 if (update_stat)
1499 unlink_free_space(block_group, left_info);
1500 else
1501 __unlink_free_space(block_group, left_info);
1502 info->offset = left_info->offset;
1503 info->bytes += left_info->bytes;
1504 kmem_cache_free(btrfs_free_space_cachep, left_info);
1505 merged = true;
1506 }
1507
1508 return merged;
1509 }
1510
1511 int btrfs_add_free_space(struct btrfs_block_group_cache *block_group,
1512 u64 offset, u64 bytes)
1513 {
1514 struct btrfs_free_space *info;
1515 int ret = 0;
1516
1517 info = kmem_cache_zalloc(btrfs_free_space_cachep, GFP_NOFS);
1518 if (!info)
1519 return -ENOMEM;
1520
1521 info->offset = offset;
1522 info->bytes = bytes;
1523
1524 spin_lock(&block_group->tree_lock);
1525
1526 if (try_merge_free_space(block_group, info, true))
1527 goto link;
1528
1529 /*
1530 * There was no extent directly to the left or right of this new
1531 * extent then we know we're going to have to allocate a new extent, so
1532 * before we do that see if we need to drop this into a bitmap
1533 */
1534 ret = insert_into_bitmap(block_group, info);
1535 if (ret < 0) {
1536 goto out;
1537 } else if (ret) {
1538 ret = 0;
1539 goto out;
1540 }
1541 link:
1542 ret = link_free_space(block_group, info);
1543 if (ret)
1544 kmem_cache_free(btrfs_free_space_cachep, info);
1545 out:
1546 spin_unlock(&block_group->tree_lock);
1547
1548 if (ret) {
1549 printk(KERN_CRIT "btrfs: unable to add free space :%d\n", ret);
1550 BUG_ON(ret == -EEXIST);
1551 }
1552
1553 return ret;
1554 }
1555
1556 int btrfs_remove_free_space(struct btrfs_block_group_cache *block_group,
1557 u64 offset, u64 bytes)
1558 {
1559 struct btrfs_free_space *info;
1560 struct btrfs_free_space *next_info = NULL;
1561 int ret = 0;
1562
1563 spin_lock(&block_group->tree_lock);
1564
1565 again:
1566 info = tree_search_offset(block_group, offset, 0, 0);
1567 if (!info) {
1568 /*
1569 * oops didn't find an extent that matched the space we wanted
1570 * to remove, look for a bitmap instead
1571 */
1572 info = tree_search_offset(block_group,
1573 offset_to_bitmap(block_group, offset),
1574 1, 0);
1575 if (!info) {
1576 WARN_ON(1);
1577 goto out_lock;
1578 }
1579 }
1580
1581 if (info->bytes < bytes && rb_next(&info->offset_index)) {
1582 u64 end;
1583 next_info = rb_entry(rb_next(&info->offset_index),
1584 struct btrfs_free_space,
1585 offset_index);
1586
1587 if (next_info->bitmap)
1588 end = next_info->offset + BITS_PER_BITMAP *
1589 block_group->sectorsize - 1;
1590 else
1591 end = next_info->offset + next_info->bytes;
1592
1593 if (next_info->bytes < bytes ||
1594 next_info->offset > offset || offset > end) {
1595 printk(KERN_CRIT "Found free space at %llu, size %llu,"
1596 " trying to use %llu\n",
1597 (unsigned long long)info->offset,
1598 (unsigned long long)info->bytes,
1599 (unsigned long long)bytes);
1600 WARN_ON(1);
1601 ret = -EINVAL;
1602 goto out_lock;
1603 }
1604
1605 info = next_info;
1606 }
1607
1608 if (info->bytes == bytes) {
1609 unlink_free_space(block_group, info);
1610 if (info->bitmap) {
1611 kfree(info->bitmap);
1612 block_group->total_bitmaps--;
1613 }
1614 kmem_cache_free(btrfs_free_space_cachep, info);
1615 goto out_lock;
1616 }
1617
1618 if (!info->bitmap && info->offset == offset) {
1619 unlink_free_space(block_group, info);
1620 info->offset += bytes;
1621 info->bytes -= bytes;
1622 link_free_space(block_group, info);
1623 goto out_lock;
1624 }
1625
1626 if (!info->bitmap && info->offset <= offset &&
1627 info->offset + info->bytes >= offset + bytes) {
1628 u64 old_start = info->offset;
1629 /*
1630 * we're freeing space in the middle of the info,
1631 * this can happen during tree log replay
1632 *
1633 * first unlink the old info and then
1634 * insert it again after the hole we're creating
1635 */
1636 unlink_free_space(block_group, info);
1637 if (offset + bytes < info->offset + info->bytes) {
1638 u64 old_end = info->offset + info->bytes;
1639
1640 info->offset = offset + bytes;
1641 info->bytes = old_end - info->offset;
1642 ret = link_free_space(block_group, info);
1643 WARN_ON(ret);
1644 if (ret)
1645 goto out_lock;
1646 } else {
1647 /* the hole we're creating ends at the end
1648 * of the info struct, just free the info
1649 */
1650 kmem_cache_free(btrfs_free_space_cachep, info);
1651 }
1652 spin_unlock(&block_group->tree_lock);
1653
1654 /* step two, insert a new info struct to cover
1655 * anything before the hole
1656 */
1657 ret = btrfs_add_free_space(block_group, old_start,
1658 offset - old_start);
1659 WARN_ON(ret);
1660 goto out;
1661 }
1662
1663 ret = remove_from_bitmap(block_group, info, &offset, &bytes);
1664 if (ret == -EAGAIN)
1665 goto again;
1666 BUG_ON(ret);
1667 out_lock:
1668 spin_unlock(&block_group->tree_lock);
1669 out:
1670 return ret;
1671 }
1672
1673 void btrfs_dump_free_space(struct btrfs_block_group_cache *block_group,
1674 u64 bytes)
1675 {
1676 struct btrfs_free_space *info;
1677 struct rb_node *n;
1678 int count = 0;
1679
1680 for (n = rb_first(&block_group->free_space_offset); n; n = rb_next(n)) {
1681 info = rb_entry(n, struct btrfs_free_space, offset_index);
1682 if (info->bytes >= bytes)
1683 count++;
1684 printk(KERN_CRIT "entry offset %llu, bytes %llu, bitmap %s\n",
1685 (unsigned long long)info->offset,
1686 (unsigned long long)info->bytes,
1687 (info->bitmap) ? "yes" : "no");
1688 }
1689 printk(KERN_INFO "block group has cluster?: %s\n",
1690 list_empty(&block_group->cluster_list) ? "no" : "yes");
1691 printk(KERN_INFO "%d blocks of free space at or bigger than bytes is"
1692 "\n", count);
1693 }
1694
1695 u64 btrfs_block_group_free_space(struct btrfs_block_group_cache *block_group)
1696 {
1697 struct btrfs_free_space *info;
1698 struct rb_node *n;
1699 u64 ret = 0;
1700
1701 for (n = rb_first(&block_group->free_space_offset); n;
1702 n = rb_next(n)) {
1703 info = rb_entry(n, struct btrfs_free_space, offset_index);
1704 ret += info->bytes;
1705 }
1706
1707 return ret;
1708 }
1709
1710 /*
1711 * for a given cluster, put all of its extents back into the free
1712 * space cache. If the block group passed doesn't match the block group
1713 * pointed to by the cluster, someone else raced in and freed the
1714 * cluster already. In that case, we just return without changing anything
1715 */
1716 static int
1717 __btrfs_return_cluster_to_free_space(
1718 struct btrfs_block_group_cache *block_group,
1719 struct btrfs_free_cluster *cluster)
1720 {
1721 struct btrfs_free_space *entry;
1722 struct rb_node *node;
1723
1724 spin_lock(&cluster->lock);
1725 if (cluster->block_group != block_group)
1726 goto out;
1727
1728 cluster->block_group = NULL;
1729 cluster->window_start = 0;
1730 list_del_init(&cluster->block_group_list);
1731
1732 node = rb_first(&cluster->root);
1733 while (node) {
1734 bool bitmap;
1735
1736 entry = rb_entry(node, struct btrfs_free_space, offset_index);
1737 node = rb_next(&entry->offset_index);
1738 rb_erase(&entry->offset_index, &cluster->root);
1739
1740 bitmap = (entry->bitmap != NULL);
1741 if (!bitmap)
1742 try_merge_free_space(block_group, entry, false);
1743 tree_insert_offset(&block_group->free_space_offset,
1744 entry->offset, &entry->offset_index, bitmap);
1745 }
1746 cluster->root = RB_ROOT;
1747
1748 out:
1749 spin_unlock(&cluster->lock);
1750 btrfs_put_block_group(block_group);
1751 return 0;
1752 }
1753
1754 void btrfs_remove_free_space_cache(struct btrfs_block_group_cache *block_group)
1755 {
1756 struct btrfs_free_space *info;
1757 struct rb_node *node;
1758 struct btrfs_free_cluster *cluster;
1759 struct list_head *head;
1760
1761 spin_lock(&block_group->tree_lock);
1762 while ((head = block_group->cluster_list.next) !=
1763 &block_group->cluster_list) {
1764 cluster = list_entry(head, struct btrfs_free_cluster,
1765 block_group_list);
1766
1767 WARN_ON(cluster->block_group != block_group);
1768 __btrfs_return_cluster_to_free_space(block_group, cluster);
1769 if (need_resched()) {
1770 spin_unlock(&block_group->tree_lock);
1771 cond_resched();
1772 spin_lock(&block_group->tree_lock);
1773 }
1774 }
1775
1776 while ((node = rb_last(&block_group->free_space_offset)) != NULL) {
1777 info = rb_entry(node, struct btrfs_free_space, offset_index);
1778 unlink_free_space(block_group, info);
1779 if (info->bitmap)
1780 kfree(info->bitmap);
1781 kmem_cache_free(btrfs_free_space_cachep, info);
1782 if (need_resched()) {
1783 spin_unlock(&block_group->tree_lock);
1784 cond_resched();
1785 spin_lock(&block_group->tree_lock);
1786 }
1787 }
1788
1789 spin_unlock(&block_group->tree_lock);
1790 }
1791
1792 u64 btrfs_find_space_for_alloc(struct btrfs_block_group_cache *block_group,
1793 u64 offset, u64 bytes, u64 empty_size)
1794 {
1795 struct btrfs_free_space *entry = NULL;
1796 u64 bytes_search = bytes + empty_size;
1797 u64 ret = 0;
1798
1799 spin_lock(&block_group->tree_lock);
1800 entry = find_free_space(block_group, &offset, &bytes_search, 0);
1801 if (!entry)
1802 goto out;
1803
1804 ret = offset;
1805 if (entry->bitmap) {
1806 bitmap_clear_bits(block_group, entry, offset, bytes);
1807 if (!entry->bytes)
1808 free_bitmap(block_group, entry);
1809 } else {
1810 unlink_free_space(block_group, entry);
1811 entry->offset += bytes;
1812 entry->bytes -= bytes;
1813 if (!entry->bytes)
1814 kmem_cache_free(btrfs_free_space_cachep, entry);
1815 else
1816 link_free_space(block_group, entry);
1817 }
1818
1819 out:
1820 spin_unlock(&block_group->tree_lock);
1821
1822 return ret;
1823 }
1824
1825 /*
1826 * given a cluster, put all of its extents back into the free space
1827 * cache. If a block group is passed, this function will only free
1828 * a cluster that belongs to the passed block group.
1829 *
1830 * Otherwise, it'll get a reference on the block group pointed to by the
1831 * cluster and remove the cluster from it.
1832 */
1833 int btrfs_return_cluster_to_free_space(
1834 struct btrfs_block_group_cache *block_group,
1835 struct btrfs_free_cluster *cluster)
1836 {
1837 int ret;
1838
1839 /* first, get a safe pointer to the block group */
1840 spin_lock(&cluster->lock);
1841 if (!block_group) {
1842 block_group = cluster->block_group;
1843 if (!block_group) {
1844 spin_unlock(&cluster->lock);
1845 return 0;
1846 }
1847 } else if (cluster->block_group != block_group) {
1848 /* someone else has already freed it don't redo their work */
1849 spin_unlock(&cluster->lock);
1850 return 0;
1851 }
1852 atomic_inc(&block_group->count);
1853 spin_unlock(&cluster->lock);
1854
1855 /* now return any extents the cluster had on it */
1856 spin_lock(&block_group->tree_lock);
1857 ret = __btrfs_return_cluster_to_free_space(block_group, cluster);
1858 spin_unlock(&block_group->tree_lock);
1859
1860 /* finally drop our ref */
1861 btrfs_put_block_group(block_group);
1862 return ret;
1863 }
1864
1865 static u64 btrfs_alloc_from_bitmap(struct btrfs_block_group_cache *block_group,
1866 struct btrfs_free_cluster *cluster,
1867 struct btrfs_free_space *entry,
1868 u64 bytes, u64 min_start)
1869 {
1870 int err;
1871 u64 search_start = cluster->window_start;
1872 u64 search_bytes = bytes;
1873 u64 ret = 0;
1874
1875 search_start = min_start;
1876 search_bytes = bytes;
1877
1878 err = search_bitmap(block_group, entry, &search_start,
1879 &search_bytes);
1880 if (err)
1881 return 0;
1882
1883 ret = search_start;
1884 bitmap_clear_bits(block_group, entry, ret, bytes);
1885
1886 return ret;
1887 }
1888
1889 /*
1890 * given a cluster, try to allocate 'bytes' from it, returns 0
1891 * if it couldn't find anything suitably large, or a logical disk offset
1892 * if things worked out
1893 */
1894 u64 btrfs_alloc_from_cluster(struct btrfs_block_group_cache *block_group,
1895 struct btrfs_free_cluster *cluster, u64 bytes,
1896 u64 min_start)
1897 {
1898 struct btrfs_free_space *entry = NULL;
1899 struct rb_node *node;
1900 u64 ret = 0;
1901
1902 spin_lock(&cluster->lock);
1903 if (bytes > cluster->max_size)
1904 goto out;
1905
1906 if (cluster->block_group != block_group)
1907 goto out;
1908
1909 node = rb_first(&cluster->root);
1910 if (!node)
1911 goto out;
1912
1913 entry = rb_entry(node, struct btrfs_free_space, offset_index);
1914 while(1) {
1915 if (entry->bytes < bytes ||
1916 (!entry->bitmap && entry->offset < min_start)) {
1917 struct rb_node *node;
1918
1919 node = rb_next(&entry->offset_index);
1920 if (!node)
1921 break;
1922 entry = rb_entry(node, struct btrfs_free_space,
1923 offset_index);
1924 continue;
1925 }
1926
1927 if (entry->bitmap) {
1928 ret = btrfs_alloc_from_bitmap(block_group,
1929 cluster, entry, bytes,
1930 min_start);
1931 if (ret == 0) {
1932 struct rb_node *node;
1933 node = rb_next(&entry->offset_index);
1934 if (!node)
1935 break;
1936 entry = rb_entry(node, struct btrfs_free_space,
1937 offset_index);
1938 continue;
1939 }
1940 } else {
1941
1942 ret = entry->offset;
1943
1944 entry->offset += bytes;
1945 entry->bytes -= bytes;
1946 }
1947
1948 if (entry->bytes == 0)
1949 rb_erase(&entry->offset_index, &cluster->root);
1950 break;
1951 }
1952 out:
1953 spin_unlock(&cluster->lock);
1954
1955 if (!ret)
1956 return 0;
1957
1958 spin_lock(&block_group->tree_lock);
1959
1960 block_group->free_space -= bytes;
1961 if (entry->bytes == 0) {
1962 block_group->free_extents--;
1963 if (entry->bitmap) {
1964 kfree(entry->bitmap);
1965 block_group->total_bitmaps--;
1966 recalculate_thresholds(block_group);
1967 }
1968 kmem_cache_free(btrfs_free_space_cachep, entry);
1969 }
1970
1971 spin_unlock(&block_group->tree_lock);
1972
1973 return ret;
1974 }
1975
1976 static int btrfs_bitmap_cluster(struct btrfs_block_group_cache *block_group,
1977 struct btrfs_free_space *entry,
1978 struct btrfs_free_cluster *cluster,
1979 u64 offset, u64 bytes, u64 min_bytes)
1980 {
1981 unsigned long next_zero;
1982 unsigned long i;
1983 unsigned long search_bits;
1984 unsigned long total_bits;
1985 unsigned long found_bits;
1986 unsigned long start = 0;
1987 unsigned long total_found = 0;
1988 int ret;
1989 bool found = false;
1990
1991 i = offset_to_bit(entry->offset, block_group->sectorsize,
1992 max_t(u64, offset, entry->offset));
1993 search_bits = bytes_to_bits(bytes, block_group->sectorsize);
1994 total_bits = bytes_to_bits(min_bytes, block_group->sectorsize);
1995
1996 again:
1997 found_bits = 0;
1998 for (i = find_next_bit(entry->bitmap, BITS_PER_BITMAP, i);
1999 i < BITS_PER_BITMAP;
2000 i = find_next_bit(entry->bitmap, BITS_PER_BITMAP, i + 1)) {
2001 next_zero = find_next_zero_bit(entry->bitmap,
2002 BITS_PER_BITMAP, i);
2003 if (next_zero - i >= search_bits) {
2004 found_bits = next_zero - i;
2005 break;
2006 }
2007 i = next_zero;
2008 }
2009
2010 if (!found_bits)
2011 return -ENOSPC;
2012
2013 if (!found) {
2014 start = i;
2015 found = true;
2016 }
2017
2018 total_found += found_bits;
2019
2020 if (cluster->max_size < found_bits * block_group->sectorsize)
2021 cluster->max_size = found_bits * block_group->sectorsize;
2022
2023 if (total_found < total_bits) {
2024 i = find_next_bit(entry->bitmap, BITS_PER_BITMAP, next_zero);
2025 if (i - start > total_bits * 2) {
2026 total_found = 0;
2027 cluster->max_size = 0;
2028 found = false;
2029 }
2030 goto again;
2031 }
2032
2033 cluster->window_start = start * block_group->sectorsize +
2034 entry->offset;
2035 rb_erase(&entry->offset_index, &block_group->free_space_offset);
2036 ret = tree_insert_offset(&cluster->root, entry->offset,
2037 &entry->offset_index, 1);
2038 BUG_ON(ret);
2039
2040 return 0;
2041 }
2042
2043 /*
2044 * This searches the block group for just extents to fill the cluster with.
2045 */
2046 static int setup_cluster_no_bitmap(struct btrfs_block_group_cache *block_group,
2047 struct btrfs_free_cluster *cluster,
2048 u64 offset, u64 bytes, u64 min_bytes)
2049 {
2050 struct btrfs_free_space *first = NULL;
2051 struct btrfs_free_space *entry = NULL;
2052 struct btrfs_free_space *prev = NULL;
2053 struct btrfs_free_space *last;
2054 struct rb_node *node;
2055 u64 window_start;
2056 u64 window_free;
2057 u64 max_extent;
2058 u64 max_gap = 128 * 1024;
2059
2060 entry = tree_search_offset(block_group, offset, 0, 1);
2061 if (!entry)
2062 return -ENOSPC;
2063
2064 /*
2065 * We don't want bitmaps, so just move along until we find a normal
2066 * extent entry.
2067 */
2068 while (entry->bitmap) {
2069 node = rb_next(&entry->offset_index);
2070 if (!node)
2071 return -ENOSPC;
2072 entry = rb_entry(node, struct btrfs_free_space, offset_index);
2073 }
2074
2075 window_start = entry->offset;
2076 window_free = entry->bytes;
2077 max_extent = entry->bytes;
2078 first = entry;
2079 last = entry;
2080 prev = entry;
2081
2082 while (window_free <= min_bytes) {
2083 node = rb_next(&entry->offset_index);
2084 if (!node)
2085 return -ENOSPC;
2086 entry = rb_entry(node, struct btrfs_free_space, offset_index);
2087
2088 if (entry->bitmap)
2089 continue;
2090 /*
2091 * we haven't filled the empty size and the window is
2092 * very large. reset and try again
2093 */
2094 if (entry->offset - (prev->offset + prev->bytes) > max_gap ||
2095 entry->offset - window_start > (min_bytes * 2)) {
2096 first = entry;
2097 window_start = entry->offset;
2098 window_free = entry->bytes;
2099 last = entry;
2100 max_extent = entry->bytes;
2101 } else {
2102 last = entry;
2103 window_free += entry->bytes;
2104 if (entry->bytes > max_extent)
2105 max_extent = entry->bytes;
2106 }
2107 prev = entry;
2108 }
2109
2110 cluster->window_start = first->offset;
2111
2112 node = &first->offset_index;
2113
2114 /*
2115 * now we've found our entries, pull them out of the free space
2116 * cache and put them into the cluster rbtree
2117 */
2118 do {
2119 int ret;
2120
2121 entry = rb_entry(node, struct btrfs_free_space, offset_index);
2122 node = rb_next(&entry->offset_index);
2123 if (entry->bitmap)
2124 continue;
2125
2126 rb_erase(&entry->offset_index, &block_group->free_space_offset);
2127 ret = tree_insert_offset(&cluster->root, entry->offset,
2128 &entry->offset_index, 0);
2129 BUG_ON(ret);
2130 } while (node && entry != last);
2131
2132 cluster->max_size = max_extent;
2133
2134 return 0;
2135 }
2136
2137 /*
2138 * This specifically looks for bitmaps that may work in the cluster, we assume
2139 * that we have already failed to find extents that will work.
2140 */
2141 static int setup_cluster_bitmap(struct btrfs_block_group_cache *block_group,
2142 struct btrfs_free_cluster *cluster,
2143 u64 offset, u64 bytes, u64 min_bytes)
2144 {
2145 struct btrfs_free_space *entry;
2146 struct rb_node *node;
2147 int ret = -ENOSPC;
2148
2149 if (block_group->total_bitmaps == 0)
2150 return -ENOSPC;
2151
2152 entry = tree_search_offset(block_group,
2153 offset_to_bitmap(block_group, offset),
2154 0, 1);
2155 if (!entry)
2156 return -ENOSPC;
2157
2158 node = &entry->offset_index;
2159 do {
2160 entry = rb_entry(node, struct btrfs_free_space, offset_index);
2161 node = rb_next(&entry->offset_index);
2162 if (!entry->bitmap)
2163 continue;
2164 if (entry->bytes < min_bytes)
2165 continue;
2166 ret = btrfs_bitmap_cluster(block_group, entry, cluster, offset,
2167 bytes, min_bytes);
2168 } while (ret && node);
2169
2170 return ret;
2171 }
2172
2173 /*
2174 * here we try to find a cluster of blocks in a block group. The goal
2175 * is to find at least bytes free and up to empty_size + bytes free.
2176 * We might not find them all in one contiguous area.
2177 *
2178 * returns zero and sets up cluster if things worked out, otherwise
2179 * it returns -enospc
2180 */
2181 int btrfs_find_space_cluster(struct btrfs_trans_handle *trans,
2182 struct btrfs_root *root,
2183 struct btrfs_block_group_cache *block_group,
2184 struct btrfs_free_cluster *cluster,
2185 u64 offset, u64 bytes, u64 empty_size)
2186 {
2187 u64 min_bytes;
2188 int ret;
2189
2190 /* for metadata, allow allocates with more holes */
2191 if (btrfs_test_opt(root, SSD_SPREAD)) {
2192 min_bytes = bytes + empty_size;
2193 } else if (block_group->flags & BTRFS_BLOCK_GROUP_METADATA) {
2194 /*
2195 * we want to do larger allocations when we are
2196 * flushing out the delayed refs, it helps prevent
2197 * making more work as we go along.
2198 */
2199 if (trans->transaction->delayed_refs.flushing)
2200 min_bytes = max(bytes, (bytes + empty_size) >> 1);
2201 else
2202 min_bytes = max(bytes, (bytes + empty_size) >> 4);
2203 } else
2204 min_bytes = max(bytes, (bytes + empty_size) >> 2);
2205
2206 spin_lock(&block_group->tree_lock);
2207
2208 /*
2209 * If we know we don't have enough space to make a cluster don't even
2210 * bother doing all the work to try and find one.
2211 */
2212 if (block_group->free_space < min_bytes) {
2213 spin_unlock(&block_group->tree_lock);
2214 return -ENOSPC;
2215 }
2216
2217 spin_lock(&cluster->lock);
2218
2219 /* someone already found a cluster, hooray */
2220 if (cluster->block_group) {
2221 ret = 0;
2222 goto out;
2223 }
2224
2225 ret = setup_cluster_no_bitmap(block_group, cluster, offset, bytes,
2226 min_bytes);
2227 if (ret)
2228 ret = setup_cluster_bitmap(block_group, cluster, offset,
2229 bytes, min_bytes);
2230
2231 if (!ret) {
2232 atomic_inc(&block_group->count);
2233 list_add_tail(&cluster->block_group_list,
2234 &block_group->cluster_list);
2235 cluster->block_group = block_group;
2236 }
2237 out:
2238 spin_unlock(&cluster->lock);
2239 spin_unlock(&block_group->tree_lock);
2240
2241 return ret;
2242 }
2243
2244 /*
2245 * simple code to zero out a cluster
2246 */
2247 void btrfs_init_free_cluster(struct btrfs_free_cluster *cluster)
2248 {
2249 spin_lock_init(&cluster->lock);
2250 spin_lock_init(&cluster->refill_lock);
2251 cluster->root = RB_ROOT;
2252 cluster->max_size = 0;
2253 INIT_LIST_HEAD(&cluster->block_group_list);
2254 cluster->block_group = NULL;
2255 }
2256
2257 int btrfs_trim_block_group(struct btrfs_block_group_cache *block_group,
2258 u64 *trimmed, u64 start, u64 end, u64 minlen)
2259 {
2260 struct btrfs_free_space *entry = NULL;
2261 struct btrfs_fs_info *fs_info = block_group->fs_info;
2262 u64 bytes = 0;
2263 u64 actually_trimmed;
2264 int ret = 0;
2265
2266 *trimmed = 0;
2267
2268 while (start < end) {
2269 spin_lock(&block_group->tree_lock);
2270
2271 if (block_group->free_space < minlen) {
2272 spin_unlock(&block_group->tree_lock);
2273 break;
2274 }
2275
2276 entry = tree_search_offset(block_group, start, 0, 1);
2277 if (!entry)
2278 entry = tree_search_offset(block_group,
2279 offset_to_bitmap(block_group,
2280 start),
2281 1, 1);
2282
2283 if (!entry || entry->offset >= end) {
2284 spin_unlock(&block_group->tree_lock);
2285 break;
2286 }
2287
2288 if (entry->bitmap) {
2289 ret = search_bitmap(block_group, entry, &start, &bytes);
2290 if (!ret) {
2291 if (start >= end) {
2292 spin_unlock(&block_group->tree_lock);
2293 break;
2294 }
2295 bytes = min(bytes, end - start);
2296 bitmap_clear_bits(block_group, entry,
2297 start, bytes);
2298 if (entry->bytes == 0)
2299 free_bitmap(block_group, entry);
2300 } else {
2301 start = entry->offset + BITS_PER_BITMAP *
2302 block_group->sectorsize;
2303 spin_unlock(&block_group->tree_lock);
2304 ret = 0;
2305 continue;
2306 }
2307 } else {
2308 start = entry->offset;
2309 bytes = min(entry->bytes, end - start);
2310 unlink_free_space(block_group, entry);
2311 kfree(entry);
2312 }
2313
2314 spin_unlock(&block_group->tree_lock);
2315
2316 if (bytes >= minlen) {
2317 int update_ret;
2318 update_ret = btrfs_update_reserved_bytes(block_group,
2319 bytes, 1, 1);
2320
2321 ret = btrfs_error_discard_extent(fs_info->extent_root,
2322 start,
2323 bytes,
2324 &actually_trimmed);
2325
2326 btrfs_add_free_space(block_group,
2327 start, bytes);
2328 if (!update_ret)
2329 btrfs_update_reserved_bytes(block_group,
2330 bytes, 0, 1);
2331
2332 if (ret)
2333 break;
2334 *trimmed += actually_trimmed;
2335 }
2336 start += bytes;
2337 bytes = 0;
2338
2339 if (fatal_signal_pending(current)) {
2340 ret = -ERESTARTSYS;
2341 break;
2342 }
2343
2344 cond_resched();
2345 }
2346
2347 return ret;
2348 }
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