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ARM: 7409/1: Do not call flush_cache_user_range with mmap_sem held
[linux/fpc-iii.git] / fs / btrfs / free-space-cache.c
blobbf0d61567f3d65a24e9d11802acdd0c8c5abf32b
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_fs_closing(root->fs_info)) {
102 block_group->inode = igrab(inode);
103 block_group->iref = 1;
104 }
105 spin_unlock(&block_group->lock);
106
107 return inode;
108 }
109
110 int __create_free_space_inode(struct btrfs_root *root,
111 struct btrfs_trans_handle *trans,
112 struct btrfs_path *path, u64 ino, u64 offset)
113 {
114 struct btrfs_key key;
115 struct btrfs_disk_key disk_key;
116 struct btrfs_free_space_header *header;
117 struct btrfs_inode_item *inode_item;
118 struct extent_buffer *leaf;
119 int ret;
120
121 ret = btrfs_insert_empty_inode(trans, root, path, ino);
122 if (ret)
123 return ret;
124
125 leaf = path->nodes[0];
126 inode_item = btrfs_item_ptr(leaf, path->slots[0],
127 struct btrfs_inode_item);
128 btrfs_item_key(leaf, &disk_key, path->slots[0]);
129 memset_extent_buffer(leaf, 0, (unsigned long)inode_item,
130 sizeof(*inode_item));
131 btrfs_set_inode_generation(leaf, inode_item, trans->transid);
132 btrfs_set_inode_size(leaf, inode_item, 0);
133 btrfs_set_inode_nbytes(leaf, inode_item, 0);
134 btrfs_set_inode_uid(leaf, inode_item, 0);
135 btrfs_set_inode_gid(leaf, inode_item, 0);
136 btrfs_set_inode_mode(leaf, inode_item, S_IFREG | 0600);
137 btrfs_set_inode_flags(leaf, inode_item, BTRFS_INODE_NOCOMPRESS |
138 BTRFS_INODE_PREALLOC | BTRFS_INODE_NODATASUM);
139 btrfs_set_inode_nlink(leaf, inode_item, 1);
140 btrfs_set_inode_transid(leaf, inode_item, trans->transid);
141 btrfs_set_inode_block_group(leaf, inode_item, offset);
142 btrfs_mark_buffer_dirty(leaf);
143 btrfs_release_path(path);
144
145 key.objectid = BTRFS_FREE_SPACE_OBJECTID;
146 key.offset = offset;
147 key.type = 0;
148
149 ret = btrfs_insert_empty_item(trans, root, path, &key,
150 sizeof(struct btrfs_free_space_header));
151 if (ret < 0) {
152 btrfs_release_path(path);
153 return ret;
154 }
155 leaf = path->nodes[0];
156 header = btrfs_item_ptr(leaf, path->slots[0],
157 struct btrfs_free_space_header);
158 memset_extent_buffer(leaf, 0, (unsigned long)header, sizeof(*header));
159 btrfs_set_free_space_key(leaf, header, &disk_key);
160 btrfs_mark_buffer_dirty(leaf);
161 btrfs_release_path(path);
162
163 return 0;
164 }
165
166 int create_free_space_inode(struct btrfs_root *root,
167 struct btrfs_trans_handle *trans,
168 struct btrfs_block_group_cache *block_group,
169 struct btrfs_path *path)
170 {
171 int ret;
172 u64 ino;
173
174 ret = btrfs_find_free_objectid(root, &ino);
175 if (ret < 0)
176 return ret;
177
178 return __create_free_space_inode(root, trans, path, ino,
179 block_group->key.objectid);
180 }
181
182 int btrfs_truncate_free_space_cache(struct btrfs_root *root,
183 struct btrfs_trans_handle *trans,
184 struct btrfs_path *path,
185 struct inode *inode)
186 {
187 loff_t oldsize;
188 int ret = 0;
189
190 trans->block_rsv = root->orphan_block_rsv;
191 ret = btrfs_block_rsv_check(trans, root,
192 root->orphan_block_rsv,
193 0, 5);
194 if (ret)
195 return ret;
196
197 oldsize = i_size_read(inode);
198 btrfs_i_size_write(inode, 0);
199 truncate_pagecache(inode, oldsize, 0);
200
201 /*
202 * We don't need an orphan item because truncating the free space cache
203 * will never be split across transactions.
204 */
205 ret = btrfs_truncate_inode_items(trans, root, inode,
206 0, BTRFS_EXTENT_DATA_KEY);
207 if (ret) {
208 WARN_ON(1);
209 return ret;
210 }
211
212 ret = btrfs_update_inode(trans, root, inode);
213 return ret;
214 }
215
216 static int readahead_cache(struct inode *inode)
217 {
218 struct file_ra_state *ra;
219 unsigned long last_index;
220
221 ra = kzalloc(sizeof(*ra), GFP_NOFS);
222 if (!ra)
223 return -ENOMEM;
224
225 file_ra_state_init(ra, inode->i_mapping);
226 last_index = (i_size_read(inode) - 1) >> PAGE_CACHE_SHIFT;
227
228 page_cache_sync_readahead(inode->i_mapping, ra, NULL, 0, last_index);
229
230 kfree(ra);
231
232 return 0;
233 }
234
235 int __load_free_space_cache(struct btrfs_root *root, struct inode *inode,
236 struct btrfs_free_space_ctl *ctl,
237 struct btrfs_path *path, u64 offset)
238 {
239 struct btrfs_free_space_header *header;
240 struct extent_buffer *leaf;
241 struct page *page;
242 u32 *checksums = NULL, *crc;
243 char *disk_crcs = NULL;
244 struct btrfs_key key;
245 struct list_head bitmaps;
246 u64 num_entries;
247 u64 num_bitmaps;
248 u64 generation;
249 u32 cur_crc = ~(u32)0;
250 pgoff_t index = 0;
251 unsigned long first_page_offset;
252 int num_checksums;
253 int ret = 0;
254
255 INIT_LIST_HEAD(&bitmaps);
256
257 /* Nothing in the space cache, goodbye */
258 if (!i_size_read(inode))
259 goto out;
260
261 key.objectid = BTRFS_FREE_SPACE_OBJECTID;
262 key.offset = offset;
263 key.type = 0;
264
265 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
266 if (ret < 0)
267 goto out;
268 else if (ret > 0) {
269 btrfs_release_path(path);
270 ret = 0;
271 goto out;
272 }
273
274 ret = -1;
275
276 leaf = path->nodes[0];
277 header = btrfs_item_ptr(leaf, path->slots[0],
278 struct btrfs_free_space_header);
279 num_entries = btrfs_free_space_entries(leaf, header);
280 num_bitmaps = btrfs_free_space_bitmaps(leaf, header);
281 generation = btrfs_free_space_generation(leaf, header);
282 btrfs_release_path(path);
283
284 if (BTRFS_I(inode)->generation != generation) {
285 printk(KERN_ERR "btrfs: free space inode generation (%llu) did"
286 " not match free space cache generation (%llu)\n",
287 (unsigned long long)BTRFS_I(inode)->generation,
288 (unsigned long long)generation);
289 goto out;
290 }
291
292 if (!num_entries)
293 goto out;
294
295 /* Setup everything for doing checksumming */
296 num_checksums = i_size_read(inode) / PAGE_CACHE_SIZE;
297 checksums = crc = kzalloc(sizeof(u32) * num_checksums, GFP_NOFS);
298 if (!checksums)
299 goto out;
300 first_page_offset = (sizeof(u32) * num_checksums) + sizeof(u64);
301 disk_crcs = kzalloc(first_page_offset, GFP_NOFS);
302 if (!disk_crcs)
303 goto out;
304
305 ret = readahead_cache(inode);
306 if (ret)
307 goto out;
308
309 while (1) {
310 struct btrfs_free_space_entry *entry;
311 struct btrfs_free_space *e;
312 void *addr;
313 unsigned long offset = 0;
314 unsigned long start_offset = 0;
315 int need_loop = 0;
316
317 if (!num_entries && !num_bitmaps)
318 break;
319
320 if (index == 0) {
321 start_offset = first_page_offset;
322 offset = start_offset;
323 }
324
325 page = grab_cache_page(inode->i_mapping, index);
326 if (!page)
327 goto free_cache;
328
329 if (!PageUptodate(page)) {
330 btrfs_readpage(NULL, page);
331 lock_page(page);
332 if (!PageUptodate(page)) {
333 unlock_page(page);
334 page_cache_release(page);
335 printk(KERN_ERR "btrfs: error reading free "
336 "space cache\n");
337 goto free_cache;
338 }
339 }
340 addr = kmap(page);
341
342 if (index == 0) {
343 u64 *gen;
344
345 memcpy(disk_crcs, addr, first_page_offset);
346 gen = addr + (sizeof(u32) * num_checksums);
347 if (*gen != BTRFS_I(inode)->generation) {
348 printk(KERN_ERR "btrfs: space cache generation"
349 " (%llu) does not match inode (%llu)\n",
350 (unsigned long long)*gen,
351 (unsigned long long)
352 BTRFS_I(inode)->generation);
353 kunmap(page);
354 unlock_page(page);
355 page_cache_release(page);
356 goto free_cache;
357 }
358 crc = (u32 *)disk_crcs;
359 }
360 entry = addr + start_offset;
361
362 /* First lets check our crc before we do anything fun */
363 cur_crc = ~(u32)0;
364 cur_crc = btrfs_csum_data(root, addr + start_offset, cur_crc,
365 PAGE_CACHE_SIZE - start_offset);
366 btrfs_csum_final(cur_crc, (char *)&cur_crc);
367 if (cur_crc != *crc) {
368 printk(KERN_ERR "btrfs: crc mismatch for page %lu\n",
369 index);
370 kunmap(page);
371 unlock_page(page);
372 page_cache_release(page);
373 goto free_cache;
374 }
375 crc++;
376
377 while (1) {
378 if (!num_entries)
379 break;
380
381 need_loop = 1;
382 e = kmem_cache_zalloc(btrfs_free_space_cachep,
383 GFP_NOFS);
384 if (!e) {
385 kunmap(page);
386 unlock_page(page);
387 page_cache_release(page);
388 goto free_cache;
389 }
390
391 e->offset = le64_to_cpu(entry->offset);
392 e->bytes = le64_to_cpu(entry->bytes);
393 if (!e->bytes) {
394 kunmap(page);
395 kmem_cache_free(btrfs_free_space_cachep, e);
396 unlock_page(page);
397 page_cache_release(page);
398 goto free_cache;
399 }
400
401 if (entry->type == BTRFS_FREE_SPACE_EXTENT) {
402 spin_lock(&ctl->tree_lock);
403 ret = link_free_space(ctl, e);
404 spin_unlock(&ctl->tree_lock);
405 if (ret) {
406 printk(KERN_ERR "Duplicate entries in "
407 "free space cache, dumping\n");
408 kunmap(page);
409 unlock_page(page);
410 page_cache_release(page);
411 goto free_cache;
412 }
413 } else {
414 e->bitmap = kzalloc(PAGE_CACHE_SIZE, GFP_NOFS);
415 if (!e->bitmap) {
416 kunmap(page);
417 kmem_cache_free(
418 btrfs_free_space_cachep, e);
419 unlock_page(page);
420 page_cache_release(page);
421 goto free_cache;
422 }
423 spin_lock(&ctl->tree_lock);
424 ret = link_free_space(ctl, e);
425 ctl->total_bitmaps++;
426 ctl->op->recalc_thresholds(ctl);
427 spin_unlock(&ctl->tree_lock);
428 if (ret) {
429 printk(KERN_ERR "Duplicate entries in "
430 "free space cache, dumping\n");
431 kunmap(page);
432 unlock_page(page);
433 page_cache_release(page);
434 goto free_cache;
435 }
436 list_add_tail(&e->list, &bitmaps);
437 }
438
439 num_entries--;
440 offset += sizeof(struct btrfs_free_space_entry);
441 if (offset + sizeof(struct btrfs_free_space_entry) >=
442 PAGE_CACHE_SIZE)
443 break;
444 entry++;
445 }
446
447 /*
448 * We read an entry out of this page, we need to move on to the
449 * next page.
450 */
451 if (need_loop) {
452 kunmap(page);
453 goto next;
454 }
455
456 /*
457 * We add the bitmaps at the end of the entries in order that
458 * the bitmap entries are added to the cache.
459 */
460 e = list_entry(bitmaps.next, struct btrfs_free_space, list);
461 list_del_init(&e->list);
462 memcpy(e->bitmap, addr, PAGE_CACHE_SIZE);
463 kunmap(page);
464 num_bitmaps--;
465 next:
466 unlock_page(page);
467 page_cache_release(page);
468 index++;
469 }
470
471 ret = 1;
472 out:
473 kfree(checksums);
474 kfree(disk_crcs);
475 return ret;
476 free_cache:
477 __btrfs_remove_free_space_cache(ctl);
478 goto out;
479 }
480
481 int load_free_space_cache(struct btrfs_fs_info *fs_info,
482 struct btrfs_block_group_cache *block_group)
483 {
484 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
485 struct btrfs_root *root = fs_info->tree_root;
486 struct inode *inode;
487 struct btrfs_path *path;
488 int ret;
489 bool matched;
490 u64 used = btrfs_block_group_used(&block_group->item);
491
492 /*
493 * If we're unmounting then just return, since this does a search on the
494 * normal root and not the commit root and we could deadlock.
495 */
496 if (btrfs_fs_closing(fs_info))
497 return 0;
498
499 /*
500 * If this block group has been marked to be cleared for one reason or
501 * another then we can't trust the on disk cache, so just return.
502 */
503 spin_lock(&block_group->lock);
504 if (block_group->disk_cache_state != BTRFS_DC_WRITTEN) {
505 spin_unlock(&block_group->lock);
506 return 0;
507 }
508 spin_unlock(&block_group->lock);
509
510 path = btrfs_alloc_path();
511 if (!path)
512 return 0;
513
514 inode = lookup_free_space_inode(root, block_group, path);
515 if (IS_ERR(inode)) {
516 btrfs_free_path(path);
517 return 0;
518 }
519
520 ret = __load_free_space_cache(fs_info->tree_root, inode, ctl,
521 path, block_group->key.objectid);
522 btrfs_free_path(path);
523 if (ret <= 0)
524 goto out;
525
526 spin_lock(&ctl->tree_lock);
527 matched = (ctl->free_space == (block_group->key.offset - used -
528 block_group->bytes_super));
529 spin_unlock(&ctl->tree_lock);
530
531 if (!matched) {
532 __btrfs_remove_free_space_cache(ctl);
533 printk(KERN_ERR "block group %llu has an wrong amount of free "
534 "space\n", block_group->key.objectid);
535 ret = -1;
536 }
537 out:
538 if (ret < 0) {
539 /* This cache is bogus, make sure it gets cleared */
540 spin_lock(&block_group->lock);
541 block_group->disk_cache_state = BTRFS_DC_CLEAR;
542 spin_unlock(&block_group->lock);
543 ret = 0;
544
545 printk(KERN_ERR "btrfs: failed to load free space cache "
546 "for block group %llu\n", block_group->key.objectid);
547 }
548
549 iput(inode);
550 return ret;
551 }
552
553 int __btrfs_write_out_cache(struct btrfs_root *root, struct inode *inode,
554 struct btrfs_free_space_ctl *ctl,
555 struct btrfs_block_group_cache *block_group,
556 struct btrfs_trans_handle *trans,
557 struct btrfs_path *path, u64 offset)
558 {
559 struct btrfs_free_space_header *header;
560 struct extent_buffer *leaf;
561 struct rb_node *node;
562 struct list_head *pos, *n;
563 struct page **pages;
564 struct page *page;
565 struct extent_state *cached_state = NULL;
566 struct btrfs_free_cluster *cluster = NULL;
567 struct extent_io_tree *unpin = NULL;
568 struct list_head bitmap_list;
569 struct btrfs_key key;
570 u64 start, end, len;
571 u64 bytes = 0;
572 u32 *crc, *checksums;
573 unsigned long first_page_offset;
574 int index = 0, num_pages = 0;
575 int entries = 0;
576 int bitmaps = 0;
577 int ret = -1;
578 bool next_page = false;
579 bool out_of_space = false;
580
581 INIT_LIST_HEAD(&bitmap_list);
582
583 node = rb_first(&ctl->free_space_offset);
584 if (!node)
585 return 0;
586
587 if (!i_size_read(inode))
588 return -1;
589
590 num_pages = (i_size_read(inode) + PAGE_CACHE_SIZE - 1) >>
591 PAGE_CACHE_SHIFT;
592
593 /* Since the first page has all of our checksums and our generation we
594 * need to calculate the offset into the page that we can start writing
595 * our entries.
596 */
597 first_page_offset = (sizeof(u32) * num_pages) + sizeof(u64);
598
599 filemap_write_and_wait(inode->i_mapping);
600 btrfs_wait_ordered_range(inode, inode->i_size &
601 ~(root->sectorsize - 1), (u64)-1);
602
603 /* make sure we don't overflow that first page */
604 if (first_page_offset + sizeof(struct btrfs_free_space_entry) >= PAGE_CACHE_SIZE) {
605 /* this is really the same as running out of space, where we also return 0 */
606 printk(KERN_CRIT "Btrfs: free space cache was too big for the crc page\n");
607 ret = 0;
608 goto out_update;
609 }
610
611 /* We need a checksum per page. */
612 crc = checksums = kzalloc(sizeof(u32) * num_pages, GFP_NOFS);
613 if (!crc)
614 return -1;
615
616 pages = kzalloc(sizeof(struct page *) * num_pages, GFP_NOFS);
617 if (!pages) {
618 kfree(crc);
619 return -1;
620 }
621
622 /* Get the cluster for this block_group if it exists */
623 if (block_group && !list_empty(&block_group->cluster_list))
624 cluster = list_entry(block_group->cluster_list.next,
625 struct btrfs_free_cluster,
626 block_group_list);
627
628 /*
629 * We shouldn't have switched the pinned extents yet so this is the
630 * right one
631 */
632 unpin = root->fs_info->pinned_extents;
633
634 /*
635 * Lock all pages first so we can lock the extent safely.
636 *
637 * NOTE: Because we hold the ref the entire time we're going to write to
638 * the page find_get_page should never fail, so we don't do a check
639 * after find_get_page at this point. Just putting this here so people
640 * know and don't freak out.
641 */
642 while (index < num_pages) {
643 page = grab_cache_page(inode->i_mapping, index);
644 if (!page) {
645 int i;
646
647 for (i = 0; i < num_pages; i++) {
648 unlock_page(pages[i]);
649 page_cache_release(pages[i]);
650 }
651 goto out_free;
652 }
653 pages[index] = page;
654 index++;
655 }
656
657 index = 0;
658 lock_extent_bits(&BTRFS_I(inode)->io_tree, 0, i_size_read(inode) - 1,
659 0, &cached_state, GFP_NOFS);
660
661 /*
662 * When searching for pinned extents, we need to start at our start
663 * offset.
664 */
665 if (block_group)
666 start = block_group->key.objectid;
667
668 /* Write out the extent entries */
669 do {
670 struct btrfs_free_space_entry *entry;
671 void *addr;
672 unsigned long offset = 0;
673 unsigned long start_offset = 0;
674
675 next_page = false;
676
677 if (index == 0) {
678 start_offset = first_page_offset;
679 offset = start_offset;
680 }
681
682 if (index >= num_pages) {
683 out_of_space = true;
684 break;
685 }
686
687 page = pages[index];
688
689 addr = kmap(page);
690 entry = addr + start_offset;
691
692 memset(addr, 0, PAGE_CACHE_SIZE);
693 while (node && !next_page) {
694 struct btrfs_free_space *e;
695
696 e = rb_entry(node, struct btrfs_free_space, offset_index);
697 entries++;
698
699 entry->offset = cpu_to_le64(e->offset);
700 entry->bytes = cpu_to_le64(e->bytes);
701 if (e->bitmap) {
702 entry->type = BTRFS_FREE_SPACE_BITMAP;
703 list_add_tail(&e->list, &bitmap_list);
704 bitmaps++;
705 } else {
706 entry->type = BTRFS_FREE_SPACE_EXTENT;
707 }
708 node = rb_next(node);
709 if (!node && cluster) {
710 node = rb_first(&cluster->root);
711 cluster = NULL;
712 }
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 /*
721 * We want to add any pinned extents to our free space cache
722 * so we don't leak the space
723 */
724 while (block_group && !next_page &&
725 (start < block_group->key.objectid +
726 block_group->key.offset)) {
727 ret = find_first_extent_bit(unpin, start, &start, &end,
728 EXTENT_DIRTY);
729 if (ret) {
730 ret = 0;
731 break;
732 }
733
734 /* This pinned extent is out of our range */
735 if (start >= block_group->key.objectid +
736 block_group->key.offset)
737 break;
738
739 len = block_group->key.objectid +
740 block_group->key.offset - start;
741 len = min(len, end + 1 - start);
742
743 entries++;
744 entry->offset = cpu_to_le64(start);
745 entry->bytes = cpu_to_le64(len);
746 entry->type = BTRFS_FREE_SPACE_EXTENT;
747
748 start = end + 1;
749 offset += sizeof(struct btrfs_free_space_entry);
750 if (offset + sizeof(struct btrfs_free_space_entry) >=
751 PAGE_CACHE_SIZE)
752 next_page = true;
753 entry++;
754 }
755 *crc = ~(u32)0;
756 *crc = btrfs_csum_data(root, addr + start_offset, *crc,
757 PAGE_CACHE_SIZE - start_offset);
758 kunmap(page);
759
760 btrfs_csum_final(*crc, (char *)crc);
761 crc++;
762
763 bytes += PAGE_CACHE_SIZE;
764
765 index++;
766 } while (node || next_page);
767
768 /* Write out the bitmaps */
769 list_for_each_safe(pos, n, &bitmap_list) {
770 void *addr;
771 struct btrfs_free_space *entry =
772 list_entry(pos, struct btrfs_free_space, list);
773
774 if (index >= num_pages) {
775 out_of_space = true;
776 break;
777 }
778 page = pages[index];
779
780 addr = kmap(page);
781 memcpy(addr, entry->bitmap, PAGE_CACHE_SIZE);
782 *crc = ~(u32)0;
783 *crc = btrfs_csum_data(root, addr, *crc, PAGE_CACHE_SIZE);
784 kunmap(page);
785 btrfs_csum_final(*crc, (char *)crc);
786 crc++;
787 bytes += PAGE_CACHE_SIZE;
788
789 list_del_init(&entry->list);
790 index++;
791 }
792
793 if (out_of_space) {
794 btrfs_drop_pages(pages, num_pages);
795 unlock_extent_cached(&BTRFS_I(inode)->io_tree, 0,
796 i_size_read(inode) - 1, &cached_state,
797 GFP_NOFS);
798 ret = 0;
799 goto out_free;
800 }
801
802 /* Zero out the rest of the pages just to make sure */
803 while (index < num_pages) {
804 void *addr;
805
806 page = pages[index];
807 addr = kmap(page);
808 memset(addr, 0, PAGE_CACHE_SIZE);
809 kunmap(page);
810 bytes += PAGE_CACHE_SIZE;
811 index++;
812 }
813
814 /* Write the checksums and trans id to the first page */
815 {
816 void *addr;
817 u64 *gen;
818
819 page = pages[0];
820
821 addr = kmap(page);
822 memcpy(addr, checksums, sizeof(u32) * num_pages);
823 gen = addr + (sizeof(u32) * num_pages);
824 *gen = trans->transid;
825 kunmap(page);
826 }
827
828 ret = btrfs_dirty_pages(root, inode, pages, num_pages, 0,
829 bytes, &cached_state);
830 btrfs_drop_pages(pages, num_pages);
831 unlock_extent_cached(&BTRFS_I(inode)->io_tree, 0,
832 i_size_read(inode) - 1, &cached_state, GFP_NOFS);
833
834 if (ret) {
835 ret = 0;
836 goto out_free;
837 }
838
839 BTRFS_I(inode)->generation = trans->transid;
840
841 filemap_write_and_wait(inode->i_mapping);
842
843 key.objectid = BTRFS_FREE_SPACE_OBJECTID;
844 key.offset = offset;
845 key.type = 0;
846
847 ret = btrfs_search_slot(trans, root, &key, path, 1, 1);
848 if (ret < 0) {
849 ret = -1;
850 clear_extent_bit(&BTRFS_I(inode)->io_tree, 0, bytes - 1,
851 EXTENT_DIRTY | EXTENT_DELALLOC |
852 EXTENT_DO_ACCOUNTING, 0, 0, NULL, GFP_NOFS);
853 goto out_free;
854 }
855 leaf = path->nodes[0];
856 if (ret > 0) {
857 struct btrfs_key found_key;
858 BUG_ON(!path->slots[0]);
859 path->slots[0]--;
860 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
861 if (found_key.objectid != BTRFS_FREE_SPACE_OBJECTID ||
862 found_key.offset != offset) {
863 ret = -1;
864 clear_extent_bit(&BTRFS_I(inode)->io_tree, 0, bytes - 1,
865 EXTENT_DIRTY | EXTENT_DELALLOC |
866 EXTENT_DO_ACCOUNTING, 0, 0, NULL,
867 GFP_NOFS);
868 btrfs_release_path(path);
869 goto out_free;
870 }
871 }
872 header = btrfs_item_ptr(leaf, path->slots[0],
873 struct btrfs_free_space_header);
874 btrfs_set_free_space_entries(leaf, header, entries);
875 btrfs_set_free_space_bitmaps(leaf, header, bitmaps);
876 btrfs_set_free_space_generation(leaf, header, trans->transid);
877 btrfs_mark_buffer_dirty(leaf);
878 btrfs_release_path(path);
879
880 ret = 1;
881
882 out_free:
883 kfree(checksums);
884 kfree(pages);
885
886 out_update:
887 if (ret != 1) {
888 invalidate_inode_pages2_range(inode->i_mapping, 0, index);
889 BTRFS_I(inode)->generation = 0;
890 }
891 btrfs_update_inode(trans, root, inode);
892 return ret;
893 }
894
895 int btrfs_write_out_cache(struct btrfs_root *root,
896 struct btrfs_trans_handle *trans,
897 struct btrfs_block_group_cache *block_group,
898 struct btrfs_path *path)
899 {
900 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
901 struct inode *inode;
902 int ret = 0;
903
904 root = root->fs_info->tree_root;
905
906 spin_lock(&block_group->lock);
907 if (block_group->disk_cache_state < BTRFS_DC_SETUP) {
908 spin_unlock(&block_group->lock);
909 return 0;
910 }
911 spin_unlock(&block_group->lock);
912
913 inode = lookup_free_space_inode(root, block_group, path);
914 if (IS_ERR(inode))
915 return 0;
916
917 ret = __btrfs_write_out_cache(root, inode, ctl, block_group, trans,
918 path, block_group->key.objectid);
919 if (ret < 0) {
920 spin_lock(&block_group->lock);
921 block_group->disk_cache_state = BTRFS_DC_ERROR;
922 spin_unlock(&block_group->lock);
923 ret = 0;
924
925 printk(KERN_ERR "btrfs: failed to write free space cace "
926 "for block group %llu\n", block_group->key.objectid);
927 }
928
929 iput(inode);
930 return ret;
931 }
932
933 static inline unsigned long offset_to_bit(u64 bitmap_start, u32 unit,
934 u64 offset)
935 {
936 BUG_ON(offset < bitmap_start);
937 offset -= bitmap_start;
938 return (unsigned long)(div_u64(offset, unit));
939 }
940
941 static inline unsigned long bytes_to_bits(u64 bytes, u32 unit)
942 {
943 return (unsigned long)(div_u64(bytes, unit));
944 }
945
946 static inline u64 offset_to_bitmap(struct btrfs_free_space_ctl *ctl,
947 u64 offset)
948 {
949 u64 bitmap_start;
950 u64 bytes_per_bitmap;
951
952 bytes_per_bitmap = BITS_PER_BITMAP * ctl->unit;
953 bitmap_start = offset - ctl->start;
954 bitmap_start = div64_u64(bitmap_start, bytes_per_bitmap);
955 bitmap_start *= bytes_per_bitmap;
956 bitmap_start += ctl->start;
957
958 return bitmap_start;
959 }
960
961 static int tree_insert_offset(struct rb_root *root, u64 offset,
962 struct rb_node *node, int bitmap)
963 {
964 struct rb_node **p = &root->rb_node;
965 struct rb_node *parent = NULL;
966 struct btrfs_free_space *info;
967
968 while (*p) {
969 parent = *p;
970 info = rb_entry(parent, struct btrfs_free_space, offset_index);
971
972 if (offset < info->offset) {
973 p = &(*p)->rb_left;
974 } else if (offset > info->offset) {
975 p = &(*p)->rb_right;
976 } else {
977 /*
978 * we could have a bitmap entry and an extent entry
979 * share the same offset. If this is the case, we want
980 * the extent entry to always be found first if we do a
981 * linear search through the tree, since we want to have
982 * the quickest allocation time, and allocating from an
983 * extent is faster than allocating from a bitmap. So
984 * if we're inserting a bitmap and we find an entry at
985 * this offset, we want to go right, or after this entry
986 * logically. If we are inserting an extent and we've
987 * found a bitmap, we want to go left, or before
988 * logically.
989 */
990 if (bitmap) {
991 if (info->bitmap) {
992 WARN_ON_ONCE(1);
993 return -EEXIST;
994 }
995 p = &(*p)->rb_right;
996 } else {
997 if (!info->bitmap) {
998 WARN_ON_ONCE(1);
999 return -EEXIST;
1000 }
1001 p = &(*p)->rb_left;
1002 }
1003 }
1004 }
1005
1006 rb_link_node(node, parent, p);
1007 rb_insert_color(node, root);
1008
1009 return 0;
1010 }
1011
1012 /*
1013 * searches the tree for the given offset.
1014 *
1015 * fuzzy - If this is set, then we are trying to make an allocation, and we just
1016 * want a section that has at least bytes size and comes at or after the given
1017 * offset.
1018 */
1019 static struct btrfs_free_space *
1020 tree_search_offset(struct btrfs_free_space_ctl *ctl,
1021 u64 offset, int bitmap_only, int fuzzy)
1022 {
1023 struct rb_node *n = ctl->free_space_offset.rb_node;
1024 struct btrfs_free_space *entry, *prev = NULL;
1025
1026 /* find entry that is closest to the 'offset' */
1027 while (1) {
1028 if (!n) {
1029 entry = NULL;
1030 break;
1031 }
1032
1033 entry = rb_entry(n, struct btrfs_free_space, offset_index);
1034 prev = entry;
1035
1036 if (offset < entry->offset)
1037 n = n->rb_left;
1038 else if (offset > entry->offset)
1039 n = n->rb_right;
1040 else
1041 break;
1042 }
1043
1044 if (bitmap_only) {
1045 if (!entry)
1046 return NULL;
1047 if (entry->bitmap)
1048 return entry;
1049
1050 /*
1051 * bitmap entry and extent entry may share same offset,
1052 * in that case, bitmap entry comes after extent entry.
1053 */
1054 n = rb_next(n);
1055 if (!n)
1056 return NULL;
1057 entry = rb_entry(n, struct btrfs_free_space, offset_index);
1058 if (entry->offset != offset)
1059 return NULL;
1060
1061 WARN_ON(!entry->bitmap);
1062 return entry;
1063 } else if (entry) {
1064 if (entry->bitmap) {
1065 /*
1066 * if previous extent entry covers the offset,
1067 * we should return it instead of the bitmap entry
1068 */
1069 n = &entry->offset_index;
1070 while (1) {
1071 n = rb_prev(n);
1072 if (!n)
1073 break;
1074 prev = rb_entry(n, struct btrfs_free_space,
1075 offset_index);
1076 if (!prev->bitmap) {
1077 if (prev->offset + prev->bytes > offset)
1078 entry = prev;
1079 break;
1080 }
1081 }
1082 }
1083 return entry;
1084 }
1085
1086 if (!prev)
1087 return NULL;
1088
1089 /* find last entry before the 'offset' */
1090 entry = prev;
1091 if (entry->offset > offset) {
1092 n = rb_prev(&entry->offset_index);
1093 if (n) {
1094 entry = rb_entry(n, struct btrfs_free_space,
1095 offset_index);
1096 BUG_ON(entry->offset > offset);
1097 } else {
1098 if (fuzzy)
1099 return entry;
1100 else
1101 return NULL;
1102 }
1103 }
1104
1105 if (entry->bitmap) {
1106 n = &entry->offset_index;
1107 while (1) {
1108 n = rb_prev(n);
1109 if (!n)
1110 break;
1111 prev = rb_entry(n, struct btrfs_free_space,
1112 offset_index);
1113 if (!prev->bitmap) {
1114 if (prev->offset + prev->bytes > offset)
1115 return prev;
1116 break;
1117 }
1118 }
1119 if (entry->offset + BITS_PER_BITMAP * ctl->unit > offset)
1120 return entry;
1121 } else if (entry->offset + entry->bytes > offset)
1122 return entry;
1123
1124 if (!fuzzy)
1125 return NULL;
1126
1127 while (1) {
1128 if (entry->bitmap) {
1129 if (entry->offset + BITS_PER_BITMAP *
1130 ctl->unit > offset)
1131 break;
1132 } else {
1133 if (entry->offset + entry->bytes > offset)
1134 break;
1135 }
1136
1137 n = rb_next(&entry->offset_index);
1138 if (!n)
1139 return NULL;
1140 entry = rb_entry(n, struct btrfs_free_space, offset_index);
1141 }
1142 return entry;
1143 }
1144
1145 static inline void
1146 __unlink_free_space(struct btrfs_free_space_ctl *ctl,
1147 struct btrfs_free_space *info)
1148 {
1149 rb_erase(&info->offset_index, &ctl->free_space_offset);
1150 ctl->free_extents--;
1151 }
1152
1153 static void unlink_free_space(struct btrfs_free_space_ctl *ctl,
1154 struct btrfs_free_space *info)
1155 {
1156 __unlink_free_space(ctl, info);
1157 ctl->free_space -= info->bytes;
1158 }
1159
1160 static int link_free_space(struct btrfs_free_space_ctl *ctl,
1161 struct btrfs_free_space *info)
1162 {
1163 int ret = 0;
1164
1165 BUG_ON(!info->bitmap && !info->bytes);
1166 ret = tree_insert_offset(&ctl->free_space_offset, info->offset,
1167 &info->offset_index, (info->bitmap != NULL));
1168 if (ret)
1169 return ret;
1170
1171 ctl->free_space += info->bytes;
1172 ctl->free_extents++;
1173 return ret;
1174 }
1175
1176 static void recalculate_thresholds(struct btrfs_free_space_ctl *ctl)
1177 {
1178 struct btrfs_block_group_cache *block_group = ctl->private;
1179 u64 max_bytes;
1180 u64 bitmap_bytes;
1181 u64 extent_bytes;
1182 u64 size = block_group->key.offset;
1183 u64 bytes_per_bg = BITS_PER_BITMAP * block_group->sectorsize;
1184 int max_bitmaps = div64_u64(size + bytes_per_bg - 1, bytes_per_bg);
1185
1186 BUG_ON(ctl->total_bitmaps > max_bitmaps);
1187
1188 /*
1189 * The goal is to keep the total amount of memory used per 1gb of space
1190 * at or below 32k, so we need to adjust how much memory we allow to be
1191 * used by extent based free space tracking
1192 */
1193 if (size < 1024 * 1024 * 1024)
1194 max_bytes = MAX_CACHE_BYTES_PER_GIG;
1195 else
1196 max_bytes = MAX_CACHE_BYTES_PER_GIG *
1197 div64_u64(size, 1024 * 1024 * 1024);
1198
1199 /*
1200 * we want to account for 1 more bitmap than what we have so we can make
1201 * sure we don't go over our overall goal of MAX_CACHE_BYTES_PER_GIG as
1202 * we add more bitmaps.
1203 */
1204 bitmap_bytes = (ctl->total_bitmaps + 1) * PAGE_CACHE_SIZE;
1205
1206 if (bitmap_bytes >= max_bytes) {
1207 ctl->extents_thresh = 0;
1208 return;
1209 }
1210
1211 /*
1212 * we want the extent entry threshold to always be at most 1/2 the maxw
1213 * bytes we can have, or whatever is less than that.
1214 */
1215 extent_bytes = max_bytes - bitmap_bytes;
1216 extent_bytes = min_t(u64, extent_bytes, div64_u64(max_bytes, 2));
1217
1218 ctl->extents_thresh =
1219 div64_u64(extent_bytes, (sizeof(struct btrfs_free_space)));
1220 }
1221
1222 static void bitmap_clear_bits(struct btrfs_free_space_ctl *ctl,
1223 struct btrfs_free_space *info, u64 offset,
1224 u64 bytes)
1225 {
1226 unsigned long start, count;
1227
1228 start = offset_to_bit(info->offset, ctl->unit, offset);
1229 count = bytes_to_bits(bytes, ctl->unit);
1230 BUG_ON(start + count > BITS_PER_BITMAP);
1231
1232 bitmap_clear(info->bitmap, start, count);
1233
1234 info->bytes -= bytes;
1235 ctl->free_space -= bytes;
1236 }
1237
1238 static void bitmap_set_bits(struct btrfs_free_space_ctl *ctl,
1239 struct btrfs_free_space *info, u64 offset,
1240 u64 bytes)
1241 {
1242 unsigned long start, count;
1243
1244 start = offset_to_bit(info->offset, ctl->unit, offset);
1245 count = bytes_to_bits(bytes, ctl->unit);
1246 BUG_ON(start + count > BITS_PER_BITMAP);
1247
1248 bitmap_set(info->bitmap, start, count);
1249
1250 info->bytes += bytes;
1251 ctl->free_space += bytes;
1252 }
1253
1254 static int search_bitmap(struct btrfs_free_space_ctl *ctl,
1255 struct btrfs_free_space *bitmap_info, u64 *offset,
1256 u64 *bytes)
1257 {
1258 unsigned long found_bits = 0;
1259 unsigned long bits, i;
1260 unsigned long next_zero;
1261
1262 i = offset_to_bit(bitmap_info->offset, ctl->unit,
1263 max_t(u64, *offset, bitmap_info->offset));
1264 bits = bytes_to_bits(*bytes, ctl->unit);
1265
1266 for (i = find_next_bit(bitmap_info->bitmap, BITS_PER_BITMAP, i);
1267 i < BITS_PER_BITMAP;
1268 i = find_next_bit(bitmap_info->bitmap, BITS_PER_BITMAP, i + 1)) {
1269 next_zero = find_next_zero_bit(bitmap_info->bitmap,
1270 BITS_PER_BITMAP, i);
1271 if ((next_zero - i) >= bits) {
1272 found_bits = next_zero - i;
1273 break;
1274 }
1275 i = next_zero;
1276 }
1277
1278 if (found_bits) {
1279 *offset = (u64)(i * ctl->unit) + bitmap_info->offset;
1280 *bytes = (u64)(found_bits) * ctl->unit;
1281 return 0;
1282 }
1283
1284 return -1;
1285 }
1286
1287 static struct btrfs_free_space *
1288 find_free_space(struct btrfs_free_space_ctl *ctl, u64 *offset, u64 *bytes)
1289 {
1290 struct btrfs_free_space *entry;
1291 struct rb_node *node;
1292 int ret;
1293
1294 if (!ctl->free_space_offset.rb_node)
1295 return NULL;
1296
1297 entry = tree_search_offset(ctl, offset_to_bitmap(ctl, *offset), 0, 1);
1298 if (!entry)
1299 return NULL;
1300
1301 for (node = &entry->offset_index; node; node = rb_next(node)) {
1302 entry = rb_entry(node, struct btrfs_free_space, offset_index);
1303 if (entry->bytes < *bytes)
1304 continue;
1305
1306 if (entry->bitmap) {
1307 ret = search_bitmap(ctl, entry, offset, bytes);
1308 if (!ret)
1309 return entry;
1310 continue;
1311 }
1312
1313 *offset = entry->offset;
1314 *bytes = entry->bytes;
1315 return entry;
1316 }
1317
1318 return NULL;
1319 }
1320
1321 static void add_new_bitmap(struct btrfs_free_space_ctl *ctl,
1322 struct btrfs_free_space *info, u64 offset)
1323 {
1324 info->offset = offset_to_bitmap(ctl, offset);
1325 info->bytes = 0;
1326 link_free_space(ctl, info);
1327 ctl->total_bitmaps++;
1328
1329 ctl->op->recalc_thresholds(ctl);
1330 }
1331
1332 static void free_bitmap(struct btrfs_free_space_ctl *ctl,
1333 struct btrfs_free_space *bitmap_info)
1334 {
1335 unlink_free_space(ctl, bitmap_info);
1336 kfree(bitmap_info->bitmap);
1337 kmem_cache_free(btrfs_free_space_cachep, bitmap_info);
1338 ctl->total_bitmaps--;
1339 ctl->op->recalc_thresholds(ctl);
1340 }
1341
1342 static noinline int remove_from_bitmap(struct btrfs_free_space_ctl *ctl,
1343 struct btrfs_free_space *bitmap_info,
1344 u64 *offset, u64 *bytes)
1345 {
1346 u64 end;
1347 u64 search_start, search_bytes;
1348 int ret;
1349
1350 again:
1351 end = bitmap_info->offset + (u64)(BITS_PER_BITMAP * ctl->unit) - 1;
1352
1353 /*
1354 * XXX - this can go away after a few releases.
1355 *
1356 * since the only user of btrfs_remove_free_space is the tree logging
1357 * stuff, and the only way to test that is under crash conditions, we
1358 * want to have this debug stuff here just in case somethings not
1359 * working. Search the bitmap for the space we are trying to use to
1360 * make sure its actually there. If its not there then we need to stop
1361 * because something has gone wrong.
1362 */
1363 search_start = *offset;
1364 search_bytes = *bytes;
1365 search_bytes = min(search_bytes, end - search_start + 1);
1366 ret = search_bitmap(ctl, bitmap_info, &search_start, &search_bytes);
1367 BUG_ON(ret < 0 || search_start != *offset);
1368
1369 if (*offset > bitmap_info->offset && *offset + *bytes > end) {
1370 bitmap_clear_bits(ctl, bitmap_info, *offset, end - *offset + 1);
1371 *bytes -= end - *offset + 1;
1372 *offset = end + 1;
1373 } else if (*offset >= bitmap_info->offset && *offset + *bytes <= end) {
1374 bitmap_clear_bits(ctl, bitmap_info, *offset, *bytes);
1375 *bytes = 0;
1376 }
1377
1378 if (*bytes) {
1379 struct rb_node *next = rb_next(&bitmap_info->offset_index);
1380 if (!bitmap_info->bytes)
1381 free_bitmap(ctl, bitmap_info);
1382
1383 /*
1384 * no entry after this bitmap, but we still have bytes to
1385 * remove, so something has gone wrong.
1386 */
1387 if (!next)
1388 return -EINVAL;
1389
1390 bitmap_info = rb_entry(next, struct btrfs_free_space,
1391 offset_index);
1392
1393 /*
1394 * if the next entry isn't a bitmap we need to return to let the
1395 * extent stuff do its work.
1396 */
1397 if (!bitmap_info->bitmap)
1398 return -EAGAIN;
1399
1400 /*
1401 * Ok the next item is a bitmap, but it may not actually hold
1402 * the information for the rest of this free space stuff, so
1403 * look for it, and if we don't find it return so we can try
1404 * everything over again.
1405 */
1406 search_start = *offset;
1407 search_bytes = *bytes;
1408 ret = search_bitmap(ctl, bitmap_info, &search_start,
1409 &search_bytes);
1410 if (ret < 0 || search_start != *offset)
1411 return -EAGAIN;
1412
1413 goto again;
1414 } else if (!bitmap_info->bytes)
1415 free_bitmap(ctl, bitmap_info);
1416
1417 return 0;
1418 }
1419
1420 static u64 add_bytes_to_bitmap(struct btrfs_free_space_ctl *ctl,
1421 struct btrfs_free_space *info, u64 offset,
1422 u64 bytes)
1423 {
1424 u64 bytes_to_set = 0;
1425 u64 end;
1426
1427 end = info->offset + (u64)(BITS_PER_BITMAP * ctl->unit);
1428
1429 bytes_to_set = min(end - offset, bytes);
1430
1431 bitmap_set_bits(ctl, info, offset, bytes_to_set);
1432
1433 return bytes_to_set;
1434
1435 }
1436
1437 static bool use_bitmap(struct btrfs_free_space_ctl *ctl,
1438 struct btrfs_free_space *info)
1439 {
1440 struct btrfs_block_group_cache *block_group = ctl->private;
1441
1442 /*
1443 * If we are below the extents threshold then we can add this as an
1444 * extent, and don't have to deal with the bitmap
1445 */
1446 if (ctl->free_extents < ctl->extents_thresh) {
1447 /*
1448 * If this block group has some small extents we don't want to
1449 * use up all of our free slots in the cache with them, we want
1450 * to reserve them to larger extents, however if we have plent
1451 * of cache left then go ahead an dadd them, no sense in adding
1452 * the overhead of a bitmap if we don't have to.
1453 */
1454 if (info->bytes <= block_group->sectorsize * 4) {
1455 if (ctl->free_extents * 2 <= ctl->extents_thresh)
1456 return false;
1457 } else {
1458 return false;
1459 }
1460 }
1461
1462 /*
1463 * some block groups are so tiny they can't be enveloped by a bitmap, so
1464 * don't even bother to create a bitmap for this
1465 */
1466 if (BITS_PER_BITMAP * block_group->sectorsize >
1467 block_group->key.offset)
1468 return false;
1469
1470 return true;
1471 }
1472
1473 static struct btrfs_free_space_op free_space_op = {
1474 .recalc_thresholds = recalculate_thresholds,
1475 .use_bitmap = use_bitmap,
1476 };
1477
1478 static int insert_into_bitmap(struct btrfs_free_space_ctl *ctl,
1479 struct btrfs_free_space *info)
1480 {
1481 struct btrfs_free_space *bitmap_info;
1482 struct btrfs_block_group_cache *block_group = NULL;
1483 int added = 0;
1484 u64 bytes, offset, bytes_added;
1485 int ret;
1486
1487 bytes = info->bytes;
1488 offset = info->offset;
1489
1490 if (!ctl->op->use_bitmap(ctl, info))
1491 return 0;
1492
1493 if (ctl->op == &free_space_op)
1494 block_group = ctl->private;
1495 again:
1496 /*
1497 * Since we link bitmaps right into the cluster we need to see if we
1498 * have a cluster here, and if so and it has our bitmap we need to add
1499 * the free space to that bitmap.
1500 */
1501 if (block_group && !list_empty(&block_group->cluster_list)) {
1502 struct btrfs_free_cluster *cluster;
1503 struct rb_node *node;
1504 struct btrfs_free_space *entry;
1505
1506 cluster = list_entry(block_group->cluster_list.next,
1507 struct btrfs_free_cluster,
1508 block_group_list);
1509 spin_lock(&cluster->lock);
1510 node = rb_first(&cluster->root);
1511 if (!node) {
1512 spin_unlock(&cluster->lock);
1513 goto no_cluster_bitmap;
1514 }
1515
1516 entry = rb_entry(node, struct btrfs_free_space, offset_index);
1517 if (!entry->bitmap) {
1518 spin_unlock(&cluster->lock);
1519 goto no_cluster_bitmap;
1520 }
1521
1522 if (entry->offset == offset_to_bitmap(ctl, offset)) {
1523 bytes_added = add_bytes_to_bitmap(ctl, entry,
1524 offset, bytes);
1525 bytes -= bytes_added;
1526 offset += bytes_added;
1527 }
1528 spin_unlock(&cluster->lock);
1529 if (!bytes) {
1530 ret = 1;
1531 goto out;
1532 }
1533 }
1534
1535 no_cluster_bitmap:
1536 bitmap_info = tree_search_offset(ctl, offset_to_bitmap(ctl, offset),
1537 1, 0);
1538 if (!bitmap_info) {
1539 BUG_ON(added);
1540 goto new_bitmap;
1541 }
1542
1543 bytes_added = add_bytes_to_bitmap(ctl, bitmap_info, offset, bytes);
1544 bytes -= bytes_added;
1545 offset += bytes_added;
1546 added = 0;
1547
1548 if (!bytes) {
1549 ret = 1;
1550 goto out;
1551 } else
1552 goto again;
1553
1554 new_bitmap:
1555 if (info && info->bitmap) {
1556 add_new_bitmap(ctl, info, offset);
1557 added = 1;
1558 info = NULL;
1559 goto again;
1560 } else {
1561 spin_unlock(&ctl->tree_lock);
1562
1563 /* no pre-allocated info, allocate a new one */
1564 if (!info) {
1565 info = kmem_cache_zalloc(btrfs_free_space_cachep,
1566 GFP_NOFS);
1567 if (!info) {
1568 spin_lock(&ctl->tree_lock);
1569 ret = -ENOMEM;
1570 goto out;
1571 }
1572 }
1573
1574 /* allocate the bitmap */
1575 info->bitmap = kzalloc(PAGE_CACHE_SIZE, GFP_NOFS);
1576 spin_lock(&ctl->tree_lock);
1577 if (!info->bitmap) {
1578 ret = -ENOMEM;
1579 goto out;
1580 }
1581 goto again;
1582 }
1583
1584 out:
1585 if (info) {
1586 if (info->bitmap)
1587 kfree(info->bitmap);
1588 kmem_cache_free(btrfs_free_space_cachep, info);
1589 }
1590
1591 return ret;
1592 }
1593
1594 static bool try_merge_free_space(struct btrfs_free_space_ctl *ctl,
1595 struct btrfs_free_space *info, bool update_stat)
1596 {
1597 struct btrfs_free_space *left_info;
1598 struct btrfs_free_space *right_info;
1599 bool merged = false;
1600 u64 offset = info->offset;
1601 u64 bytes = info->bytes;
1602
1603 /*
1604 * first we want to see if there is free space adjacent to the range we
1605 * are adding, if there is remove that struct and add a new one to
1606 * cover the entire range
1607 */
1608 right_info = tree_search_offset(ctl, offset + bytes, 0, 0);
1609 if (right_info && rb_prev(&right_info->offset_index))
1610 left_info = rb_entry(rb_prev(&right_info->offset_index),
1611 struct btrfs_free_space, offset_index);
1612 else
1613 left_info = tree_search_offset(ctl, offset - 1, 0, 0);
1614
1615 if (right_info && !right_info->bitmap) {
1616 if (update_stat)
1617 unlink_free_space(ctl, right_info);
1618 else
1619 __unlink_free_space(ctl, right_info);
1620 info->bytes += right_info->bytes;
1621 kmem_cache_free(btrfs_free_space_cachep, right_info);
1622 merged = true;
1623 }
1624
1625 if (left_info && !left_info->bitmap &&
1626 left_info->offset + left_info->bytes == offset) {
1627 if (update_stat)
1628 unlink_free_space(ctl, left_info);
1629 else
1630 __unlink_free_space(ctl, left_info);
1631 info->offset = left_info->offset;
1632 info->bytes += left_info->bytes;
1633 kmem_cache_free(btrfs_free_space_cachep, left_info);
1634 merged = true;
1635 }
1636
1637 return merged;
1638 }
1639
1640 int __btrfs_add_free_space(struct btrfs_free_space_ctl *ctl,
1641 u64 offset, u64 bytes)
1642 {
1643 struct btrfs_free_space *info;
1644 int ret = 0;
1645
1646 info = kmem_cache_zalloc(btrfs_free_space_cachep, GFP_NOFS);
1647 if (!info)
1648 return -ENOMEM;
1649
1650 info->offset = offset;
1651 info->bytes = bytes;
1652
1653 spin_lock(&ctl->tree_lock);
1654
1655 if (try_merge_free_space(ctl, info, true))
1656 goto link;
1657
1658 /*
1659 * There was no extent directly to the left or right of this new
1660 * extent then we know we're going to have to allocate a new extent, so
1661 * before we do that see if we need to drop this into a bitmap
1662 */
1663 ret = insert_into_bitmap(ctl, info);
1664 if (ret < 0) {
1665 goto out;
1666 } else if (ret) {
1667 ret = 0;
1668 goto out;
1669 }
1670 link:
1671 ret = link_free_space(ctl, info);
1672 if (ret)
1673 kmem_cache_free(btrfs_free_space_cachep, info);
1674 out:
1675 spin_unlock(&ctl->tree_lock);
1676
1677 if (ret) {
1678 printk(KERN_CRIT "btrfs: unable to add free space :%d\n", ret);
1679 BUG_ON(ret == -EEXIST);
1680 }
1681
1682 return ret;
1683 }
1684
1685 int btrfs_remove_free_space(struct btrfs_block_group_cache *block_group,
1686 u64 offset, u64 bytes)
1687 {
1688 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
1689 struct btrfs_free_space *info;
1690 struct btrfs_free_space *next_info = NULL;
1691 int ret = 0;
1692
1693 spin_lock(&ctl->tree_lock);
1694
1695 again:
1696 info = tree_search_offset(ctl, offset, 0, 0);
1697 if (!info) {
1698 /*
1699 * oops didn't find an extent that matched the space we wanted
1700 * to remove, look for a bitmap instead
1701 */
1702 info = tree_search_offset(ctl, offset_to_bitmap(ctl, offset),
1703 1, 0);
1704 if (!info) {
1705 WARN_ON(1);
1706 goto out_lock;
1707 }
1708 }
1709
1710 if (info->bytes < bytes && rb_next(&info->offset_index)) {
1711 u64 end;
1712 next_info = rb_entry(rb_next(&info->offset_index),
1713 struct btrfs_free_space,
1714 offset_index);
1715
1716 if (next_info->bitmap)
1717 end = next_info->offset +
1718 BITS_PER_BITMAP * ctl->unit - 1;
1719 else
1720 end = next_info->offset + next_info->bytes;
1721
1722 if (next_info->bytes < bytes ||
1723 next_info->offset > offset || offset > end) {
1724 printk(KERN_CRIT "Found free space at %llu, size %llu,"
1725 " trying to use %llu\n",
1726 (unsigned long long)info->offset,
1727 (unsigned long long)info->bytes,
1728 (unsigned long long)bytes);
1729 WARN_ON(1);
1730 ret = -EINVAL;
1731 goto out_lock;
1732 }
1733
1734 info = next_info;
1735 }
1736
1737 if (info->bytes == bytes) {
1738 unlink_free_space(ctl, info);
1739 if (info->bitmap) {
1740 kfree(info->bitmap);
1741 ctl->total_bitmaps--;
1742 }
1743 kmem_cache_free(btrfs_free_space_cachep, info);
1744 goto out_lock;
1745 }
1746
1747 if (!info->bitmap && info->offset == offset) {
1748 unlink_free_space(ctl, info);
1749 info->offset += bytes;
1750 info->bytes -= bytes;
1751 link_free_space(ctl, info);
1752 goto out_lock;
1753 }
1754
1755 if (!info->bitmap && info->offset <= offset &&
1756 info->offset + info->bytes >= offset + bytes) {
1757 u64 old_start = info->offset;
1758 /*
1759 * we're freeing space in the middle of the info,
1760 * this can happen during tree log replay
1761 *
1762 * first unlink the old info and then
1763 * insert it again after the hole we're creating
1764 */
1765 unlink_free_space(ctl, info);
1766 if (offset + bytes < info->offset + info->bytes) {
1767 u64 old_end = info->offset + info->bytes;
1768
1769 info->offset = offset + bytes;
1770 info->bytes = old_end - info->offset;
1771 ret = link_free_space(ctl, info);
1772 WARN_ON(ret);
1773 if (ret)
1774 goto out_lock;
1775 } else {
1776 /* the hole we're creating ends at the end
1777 * of the info struct, just free the info
1778 */
1779 kmem_cache_free(btrfs_free_space_cachep, info);
1780 }
1781 spin_unlock(&ctl->tree_lock);
1782
1783 /* step two, insert a new info struct to cover
1784 * anything before the hole
1785 */
1786 ret = btrfs_add_free_space(block_group, old_start,
1787 offset - old_start);
1788 WARN_ON(ret);
1789 goto out;
1790 }
1791
1792 ret = remove_from_bitmap(ctl, info, &offset, &bytes);
1793 if (ret == -EAGAIN)
1794 goto again;
1795 BUG_ON(ret);
1796 out_lock:
1797 spin_unlock(&ctl->tree_lock);
1798 out:
1799 return ret;
1800 }
1801
1802 void btrfs_dump_free_space(struct btrfs_block_group_cache *block_group,
1803 u64 bytes)
1804 {
1805 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
1806 struct btrfs_free_space *info;
1807 struct rb_node *n;
1808 int count = 0;
1809
1810 for (n = rb_first(&ctl->free_space_offset); n; n = rb_next(n)) {
1811 info = rb_entry(n, struct btrfs_free_space, offset_index);
1812 if (info->bytes >= bytes)
1813 count++;
1814 printk(KERN_CRIT "entry offset %llu, bytes %llu, bitmap %s\n",
1815 (unsigned long long)info->offset,
1816 (unsigned long long)info->bytes,
1817 (info->bitmap) ? "yes" : "no");
1818 }
1819 printk(KERN_INFO "block group has cluster?: %s\n",
1820 list_empty(&block_group->cluster_list) ? "no" : "yes");
1821 printk(KERN_INFO "%d blocks of free space at or bigger than bytes is"
1822 "\n", count);
1823 }
1824
1825 void btrfs_init_free_space_ctl(struct btrfs_block_group_cache *block_group)
1826 {
1827 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
1828
1829 spin_lock_init(&ctl->tree_lock);
1830 ctl->unit = block_group->sectorsize;
1831 ctl->start = block_group->key.objectid;
1832 ctl->private = block_group;
1833 ctl->op = &free_space_op;
1834
1835 /*
1836 * we only want to have 32k of ram per block group for keeping
1837 * track of free space, and if we pass 1/2 of that we want to
1838 * start converting things over to using bitmaps
1839 */
1840 ctl->extents_thresh = ((1024 * 32) / 2) /
1841 sizeof(struct btrfs_free_space);
1842 }
1843
1844 /*
1845 * for a given cluster, put all of its extents back into the free
1846 * space cache. If the block group passed doesn't match the block group
1847 * pointed to by the cluster, someone else raced in and freed the
1848 * cluster already. In that case, we just return without changing anything
1849 */
1850 static int
1851 __btrfs_return_cluster_to_free_space(
1852 struct btrfs_block_group_cache *block_group,
1853 struct btrfs_free_cluster *cluster)
1854 {
1855 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
1856 struct btrfs_free_space *entry;
1857 struct rb_node *node;
1858
1859 spin_lock(&cluster->lock);
1860 if (cluster->block_group != block_group)
1861 goto out;
1862
1863 cluster->block_group = NULL;
1864 cluster->window_start = 0;
1865 list_del_init(&cluster->block_group_list);
1866
1867 node = rb_first(&cluster->root);
1868 while (node) {
1869 bool bitmap;
1870
1871 entry = rb_entry(node, struct btrfs_free_space, offset_index);
1872 node = rb_next(&entry->offset_index);
1873 rb_erase(&entry->offset_index, &cluster->root);
1874
1875 bitmap = (entry->bitmap != NULL);
1876 if (!bitmap)
1877 try_merge_free_space(ctl, entry, false);
1878 tree_insert_offset(&ctl->free_space_offset,
1879 entry->offset, &entry->offset_index, bitmap);
1880 }
1881 cluster->root = RB_ROOT;
1882
1883 out:
1884 spin_unlock(&cluster->lock);
1885 btrfs_put_block_group(block_group);
1886 return 0;
1887 }
1888
1889 void __btrfs_remove_free_space_cache_locked(struct btrfs_free_space_ctl *ctl)
1890 {
1891 struct btrfs_free_space *info;
1892 struct rb_node *node;
1893
1894 while ((node = rb_last(&ctl->free_space_offset)) != NULL) {
1895 info = rb_entry(node, struct btrfs_free_space, offset_index);
1896 if (!info->bitmap) {
1897 unlink_free_space(ctl, info);
1898 kmem_cache_free(btrfs_free_space_cachep, info);
1899 } else {
1900 free_bitmap(ctl, info);
1901 }
1902 if (need_resched()) {
1903 spin_unlock(&ctl->tree_lock);
1904 cond_resched();
1905 spin_lock(&ctl->tree_lock);
1906 }
1907 }
1908 }
1909
1910 void __btrfs_remove_free_space_cache(struct btrfs_free_space_ctl *ctl)
1911 {
1912 spin_lock(&ctl->tree_lock);
1913 __btrfs_remove_free_space_cache_locked(ctl);
1914 spin_unlock(&ctl->tree_lock);
1915 }
1916
1917 void btrfs_remove_free_space_cache(struct btrfs_block_group_cache *block_group)
1918 {
1919 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
1920 struct btrfs_free_cluster *cluster;
1921 struct list_head *head;
1922
1923 spin_lock(&ctl->tree_lock);
1924 while ((head = block_group->cluster_list.next) !=
1925 &block_group->cluster_list) {
1926 cluster = list_entry(head, struct btrfs_free_cluster,
1927 block_group_list);
1928
1929 WARN_ON(cluster->block_group != block_group);
1930 __btrfs_return_cluster_to_free_space(block_group, cluster);
1931 if (need_resched()) {
1932 spin_unlock(&ctl->tree_lock);
1933 cond_resched();
1934 spin_lock(&ctl->tree_lock);
1935 }
1936 }
1937 __btrfs_remove_free_space_cache_locked(ctl);
1938 spin_unlock(&ctl->tree_lock);
1939
1940 }
1941
1942 u64 btrfs_find_space_for_alloc(struct btrfs_block_group_cache *block_group,
1943 u64 offset, u64 bytes, u64 empty_size)
1944 {
1945 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
1946 struct btrfs_free_space *entry = NULL;
1947 u64 bytes_search = bytes + empty_size;
1948 u64 ret = 0;
1949
1950 spin_lock(&ctl->tree_lock);
1951 entry = find_free_space(ctl, &offset, &bytes_search);
1952 if (!entry)
1953 goto out;
1954
1955 ret = offset;
1956 if (entry->bitmap) {
1957 bitmap_clear_bits(ctl, entry, offset, bytes);
1958 if (!entry->bytes)
1959 free_bitmap(ctl, entry);
1960 } else {
1961 unlink_free_space(ctl, entry);
1962 entry->offset += bytes;
1963 entry->bytes -= bytes;
1964 if (!entry->bytes)
1965 kmem_cache_free(btrfs_free_space_cachep, entry);
1966 else
1967 link_free_space(ctl, entry);
1968 }
1969
1970 out:
1971 spin_unlock(&ctl->tree_lock);
1972
1973 return ret;
1974 }
1975
1976 /*
1977 * given a cluster, put all of its extents back into the free space
1978 * cache. If a block group is passed, this function will only free
1979 * a cluster that belongs to the passed block group.
1980 *
1981 * Otherwise, it'll get a reference on the block group pointed to by the
1982 * cluster and remove the cluster from it.
1983 */
1984 int btrfs_return_cluster_to_free_space(
1985 struct btrfs_block_group_cache *block_group,
1986 struct btrfs_free_cluster *cluster)
1987 {
1988 struct btrfs_free_space_ctl *ctl;
1989 int ret;
1990
1991 /* first, get a safe pointer to the block group */
1992 spin_lock(&cluster->lock);
1993 if (!block_group) {
1994 block_group = cluster->block_group;
1995 if (!block_group) {
1996 spin_unlock(&cluster->lock);
1997 return 0;
1998 }
1999 } else if (cluster->block_group != block_group) {
2000 /* someone else has already freed it don't redo their work */
2001 spin_unlock(&cluster->lock);
2002 return 0;
2003 }
2004 atomic_inc(&block_group->count);
2005 spin_unlock(&cluster->lock);
2006
2007 ctl = block_group->free_space_ctl;
2008
2009 /* now return any extents the cluster had on it */
2010 spin_lock(&ctl->tree_lock);
2011 ret = __btrfs_return_cluster_to_free_space(block_group, cluster);
2012 spin_unlock(&ctl->tree_lock);
2013
2014 /* finally drop our ref */
2015 btrfs_put_block_group(block_group);
2016 return ret;
2017 }
2018
2019 static u64 btrfs_alloc_from_bitmap(struct btrfs_block_group_cache *block_group,
2020 struct btrfs_free_cluster *cluster,
2021 struct btrfs_free_space *entry,
2022 u64 bytes, u64 min_start)
2023 {
2024 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2025 int err;
2026 u64 search_start = cluster->window_start;
2027 u64 search_bytes = bytes;
2028 u64 ret = 0;
2029
2030 search_start = min_start;
2031 search_bytes = bytes;
2032
2033 err = search_bitmap(ctl, entry, &search_start, &search_bytes);
2034 if (err)
2035 return 0;
2036
2037 ret = search_start;
2038 bitmap_clear_bits(ctl, entry, ret, bytes);
2039
2040 return ret;
2041 }
2042
2043 /*
2044 * given a cluster, try to allocate 'bytes' from it, returns 0
2045 * if it couldn't find anything suitably large, or a logical disk offset
2046 * if things worked out
2047 */
2048 u64 btrfs_alloc_from_cluster(struct btrfs_block_group_cache *block_group,
2049 struct btrfs_free_cluster *cluster, u64 bytes,
2050 u64 min_start)
2051 {
2052 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2053 struct btrfs_free_space *entry = NULL;
2054 struct rb_node *node;
2055 u64 ret = 0;
2056
2057 spin_lock(&cluster->lock);
2058 if (bytes > cluster->max_size)
2059 goto out;
2060
2061 if (cluster->block_group != block_group)
2062 goto out;
2063
2064 node = rb_first(&cluster->root);
2065 if (!node)
2066 goto out;
2067
2068 entry = rb_entry(node, struct btrfs_free_space, offset_index);
2069 while(1) {
2070 if (entry->bytes < bytes ||
2071 (!entry->bitmap && entry->offset < min_start)) {
2072 node = rb_next(&entry->offset_index);
2073 if (!node)
2074 break;
2075 entry = rb_entry(node, struct btrfs_free_space,
2076 offset_index);
2077 continue;
2078 }
2079
2080 if (entry->bitmap) {
2081 ret = btrfs_alloc_from_bitmap(block_group,
2082 cluster, entry, bytes,
2083 min_start);
2084 if (ret == 0) {
2085 node = rb_next(&entry->offset_index);
2086 if (!node)
2087 break;
2088 entry = rb_entry(node, struct btrfs_free_space,
2089 offset_index);
2090 continue;
2091 }
2092 } else {
2093
2094 ret = entry->offset;
2095
2096 entry->offset += bytes;
2097 entry->bytes -= bytes;
2098 }
2099
2100 if (entry->bytes == 0)
2101 rb_erase(&entry->offset_index, &cluster->root);
2102 break;
2103 }
2104 out:
2105 spin_unlock(&cluster->lock);
2106
2107 if (!ret)
2108 return 0;
2109
2110 spin_lock(&ctl->tree_lock);
2111
2112 ctl->free_space -= bytes;
2113 if (entry->bytes == 0) {
2114 ctl->free_extents--;
2115 if (entry->bitmap) {
2116 kfree(entry->bitmap);
2117 ctl->total_bitmaps--;
2118 ctl->op->recalc_thresholds(ctl);
2119 }
2120 kmem_cache_free(btrfs_free_space_cachep, entry);
2121 }
2122
2123 spin_unlock(&ctl->tree_lock);
2124
2125 return ret;
2126 }
2127
2128 static int btrfs_bitmap_cluster(struct btrfs_block_group_cache *block_group,
2129 struct btrfs_free_space *entry,
2130 struct btrfs_free_cluster *cluster,
2131 u64 offset, u64 bytes, u64 min_bytes)
2132 {
2133 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2134 unsigned long next_zero;
2135 unsigned long i;
2136 unsigned long search_bits;
2137 unsigned long total_bits;
2138 unsigned long found_bits;
2139 unsigned long start = 0;
2140 unsigned long total_found = 0;
2141 int ret;
2142 bool found = false;
2143
2144 i = offset_to_bit(entry->offset, block_group->sectorsize,
2145 max_t(u64, offset, entry->offset));
2146 search_bits = bytes_to_bits(bytes, block_group->sectorsize);
2147 total_bits = bytes_to_bits(min_bytes, block_group->sectorsize);
2148
2149 again:
2150 found_bits = 0;
2151 for (i = find_next_bit(entry->bitmap, BITS_PER_BITMAP, i);
2152 i < BITS_PER_BITMAP;
2153 i = find_next_bit(entry->bitmap, BITS_PER_BITMAP, i + 1)) {
2154 next_zero = find_next_zero_bit(entry->bitmap,
2155 BITS_PER_BITMAP, i);
2156 if (next_zero - i >= search_bits) {
2157 found_bits = next_zero - i;
2158 break;
2159 }
2160 i = next_zero;
2161 }
2162
2163 if (!found_bits)
2164 return -ENOSPC;
2165
2166 if (!found) {
2167 start = i;
2168 found = true;
2169 }
2170
2171 total_found += found_bits;
2172
2173 if (cluster->max_size < found_bits * block_group->sectorsize)
2174 cluster->max_size = found_bits * block_group->sectorsize;
2175
2176 if (total_found < total_bits) {
2177 i = find_next_bit(entry->bitmap, BITS_PER_BITMAP, next_zero);
2178 if (i - start > total_bits * 2) {
2179 total_found = 0;
2180 cluster->max_size = 0;
2181 found = false;
2182 }
2183 goto again;
2184 }
2185
2186 cluster->window_start = start * block_group->sectorsize +
2187 entry->offset;
2188 rb_erase(&entry->offset_index, &ctl->free_space_offset);
2189 ret = tree_insert_offset(&cluster->root, entry->offset,
2190 &entry->offset_index, 1);
2191 BUG_ON(ret);
2192
2193 return 0;
2194 }
2195
2196 /*
2197 * This searches the block group for just extents to fill the cluster with.
2198 */
2199 static noinline int
2200 setup_cluster_no_bitmap(struct btrfs_block_group_cache *block_group,
2201 struct btrfs_free_cluster *cluster,
2202 struct list_head *bitmaps, u64 offset, u64 bytes,
2203 u64 min_bytes)
2204 {
2205 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2206 struct btrfs_free_space *first = NULL;
2207 struct btrfs_free_space *entry = NULL;
2208 struct btrfs_free_space *prev = NULL;
2209 struct btrfs_free_space *last;
2210 struct rb_node *node;
2211 u64 window_start;
2212 u64 window_free;
2213 u64 max_extent;
2214 u64 max_gap = 128 * 1024;
2215
2216 entry = tree_search_offset(ctl, offset, 0, 1);
2217 if (!entry)
2218 return -ENOSPC;
2219
2220 /*
2221 * We don't want bitmaps, so just move along until we find a normal
2222 * extent entry.
2223 */
2224 while (entry->bitmap) {
2225 if (list_empty(&entry->list))
2226 list_add_tail(&entry->list, bitmaps);
2227 node = rb_next(&entry->offset_index);
2228 if (!node)
2229 return -ENOSPC;
2230 entry = rb_entry(node, struct btrfs_free_space, offset_index);
2231 }
2232
2233 window_start = entry->offset;
2234 window_free = entry->bytes;
2235 max_extent = entry->bytes;
2236 first = entry;
2237 last = entry;
2238 prev = entry;
2239
2240 while (window_free <= min_bytes) {
2241 node = rb_next(&entry->offset_index);
2242 if (!node)
2243 return -ENOSPC;
2244 entry = rb_entry(node, struct btrfs_free_space, offset_index);
2245
2246 if (entry->bitmap) {
2247 if (list_empty(&entry->list))
2248 list_add_tail(&entry->list, bitmaps);
2249 continue;
2250 }
2251
2252 /*
2253 * we haven't filled the empty size and the window is
2254 * very large. reset and try again
2255 */
2256 if (entry->offset - (prev->offset + prev->bytes) > max_gap ||
2257 entry->offset - window_start > (min_bytes * 2)) {
2258 first = entry;
2259 window_start = entry->offset;
2260 window_free = entry->bytes;
2261 last = entry;
2262 max_extent = entry->bytes;
2263 } else {
2264 last = entry;
2265 window_free += entry->bytes;
2266 if (entry->bytes > max_extent)
2267 max_extent = entry->bytes;
2268 }
2269 prev = entry;
2270 }
2271
2272 cluster->window_start = first->offset;
2273
2274 node = &first->offset_index;
2275
2276 /*
2277 * now we've found our entries, pull them out of the free space
2278 * cache and put them into the cluster rbtree
2279 */
2280 do {
2281 int ret;
2282
2283 entry = rb_entry(node, struct btrfs_free_space, offset_index);
2284 node = rb_next(&entry->offset_index);
2285 if (entry->bitmap)
2286 continue;
2287
2288 rb_erase(&entry->offset_index, &ctl->free_space_offset);
2289 ret = tree_insert_offset(&cluster->root, entry->offset,
2290 &entry->offset_index, 0);
2291 BUG_ON(ret);
2292 } while (node && entry != last);
2293
2294 cluster->max_size = max_extent;
2295
2296 return 0;
2297 }
2298
2299 /*
2300 * This specifically looks for bitmaps that may work in the cluster, we assume
2301 * that we have already failed to find extents that will work.
2302 */
2303 static noinline int
2304 setup_cluster_bitmap(struct btrfs_block_group_cache *block_group,
2305 struct btrfs_free_cluster *cluster,
2306 struct list_head *bitmaps, u64 offset, u64 bytes,
2307 u64 min_bytes)
2308 {
2309 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2310 struct btrfs_free_space *entry;
2311 struct rb_node *node;
2312 int ret = -ENOSPC;
2313
2314 if (ctl->total_bitmaps == 0)
2315 return -ENOSPC;
2316
2317 /*
2318 * First check our cached list of bitmaps and see if there is an entry
2319 * here that will work.
2320 */
2321 list_for_each_entry(entry, bitmaps, list) {
2322 if (entry->bytes < min_bytes)
2323 continue;
2324 ret = btrfs_bitmap_cluster(block_group, entry, cluster, offset,
2325 bytes, min_bytes);
2326 if (!ret)
2327 return 0;
2328 }
2329
2330 /*
2331 * If we do have entries on our list and we are here then we didn't find
2332 * anything, so go ahead and get the next entry after the last entry in
2333 * this list and start the search from there.
2334 */
2335 if (!list_empty(bitmaps)) {
2336 entry = list_entry(bitmaps->prev, struct btrfs_free_space,
2337 list);
2338 node = rb_next(&entry->offset_index);
2339 if (!node)
2340 return -ENOSPC;
2341 entry = rb_entry(node, struct btrfs_free_space, offset_index);
2342 goto search;
2343 }
2344
2345 entry = tree_search_offset(ctl, offset_to_bitmap(ctl, offset), 0, 1);
2346 if (!entry)
2347 return -ENOSPC;
2348
2349 search:
2350 node = &entry->offset_index;
2351 do {
2352 entry = rb_entry(node, struct btrfs_free_space, offset_index);
2353 node = rb_next(&entry->offset_index);
2354 if (!entry->bitmap)
2355 continue;
2356 if (entry->bytes < min_bytes)
2357 continue;
2358 ret = btrfs_bitmap_cluster(block_group, entry, cluster, offset,
2359 bytes, min_bytes);
2360 } while (ret && node);
2361
2362 return ret;
2363 }
2364
2365 /*
2366 * here we try to find a cluster of blocks in a block group. The goal
2367 * is to find at least bytes free and up to empty_size + bytes free.
2368 * We might not find them all in one contiguous area.
2369 *
2370 * returns zero and sets up cluster if things worked out, otherwise
2371 * it returns -enospc
2372 */
2373 int btrfs_find_space_cluster(struct btrfs_trans_handle *trans,
2374 struct btrfs_root *root,
2375 struct btrfs_block_group_cache *block_group,
2376 struct btrfs_free_cluster *cluster,
2377 u64 offset, u64 bytes, u64 empty_size)
2378 {
2379 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2380 struct list_head bitmaps;
2381 struct btrfs_free_space *entry, *tmp;
2382 u64 min_bytes;
2383 int ret;
2384
2385 /* for metadata, allow allocates with more holes */
2386 if (btrfs_test_opt(root, SSD_SPREAD)) {
2387 min_bytes = bytes + empty_size;
2388 } else if (block_group->flags & BTRFS_BLOCK_GROUP_METADATA) {
2389 /*
2390 * we want to do larger allocations when we are
2391 * flushing out the delayed refs, it helps prevent
2392 * making more work as we go along.
2393 */
2394 if (trans->transaction->delayed_refs.flushing)
2395 min_bytes = max(bytes, (bytes + empty_size) >> 1);
2396 else
2397 min_bytes = max(bytes, (bytes + empty_size) >> 4);
2398 } else
2399 min_bytes = max(bytes, (bytes + empty_size) >> 2);
2400
2401 spin_lock(&ctl->tree_lock);
2402
2403 /*
2404 * If we know we don't have enough space to make a cluster don't even
2405 * bother doing all the work to try and find one.
2406 */
2407 if (ctl->free_space < min_bytes) {
2408 spin_unlock(&ctl->tree_lock);
2409 return -ENOSPC;
2410 }
2411
2412 spin_lock(&cluster->lock);
2413
2414 /* someone already found a cluster, hooray */
2415 if (cluster->block_group) {
2416 ret = 0;
2417 goto out;
2418 }
2419
2420 INIT_LIST_HEAD(&bitmaps);
2421 ret = setup_cluster_no_bitmap(block_group, cluster, &bitmaps, offset,
2422 bytes, min_bytes);
2423 if (ret)
2424 ret = setup_cluster_bitmap(block_group, cluster, &bitmaps,
2425 offset, bytes, min_bytes);
2426
2427 /* Clear our temporary list */
2428 list_for_each_entry_safe(entry, tmp, &bitmaps, list)
2429 list_del_init(&entry->list);
2430
2431 if (!ret) {
2432 atomic_inc(&block_group->count);
2433 list_add_tail(&cluster->block_group_list,
2434 &block_group->cluster_list);
2435 cluster->block_group = block_group;
2436 }
2437 out:
2438 spin_unlock(&cluster->lock);
2439 spin_unlock(&ctl->tree_lock);
2440
2441 return ret;
2442 }
2443
2444 /*
2445 * simple code to zero out a cluster
2446 */
2447 void btrfs_init_free_cluster(struct btrfs_free_cluster *cluster)
2448 {
2449 spin_lock_init(&cluster->lock);
2450 spin_lock_init(&cluster->refill_lock);
2451 cluster->root = RB_ROOT;
2452 cluster->max_size = 0;
2453 INIT_LIST_HEAD(&cluster->block_group_list);
2454 cluster->block_group = NULL;
2455 }
2456
2457 int btrfs_trim_block_group(struct btrfs_block_group_cache *block_group,
2458 u64 *trimmed, u64 start, u64 end, u64 minlen)
2459 {
2460 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2461 struct btrfs_free_space *entry = NULL;
2462 struct btrfs_fs_info *fs_info = block_group->fs_info;
2463 u64 bytes = 0;
2464 u64 actually_trimmed;
2465 int ret = 0;
2466
2467 *trimmed = 0;
2468
2469 while (start < end) {
2470 spin_lock(&ctl->tree_lock);
2471
2472 if (ctl->free_space < minlen) {
2473 spin_unlock(&ctl->tree_lock);
2474 break;
2475 }
2476
2477 entry = tree_search_offset(ctl, start, 0, 1);
2478 if (!entry)
2479 entry = tree_search_offset(ctl,
2480 offset_to_bitmap(ctl, start),
2481 1, 1);
2482
2483 if (!entry || entry->offset >= end) {
2484 spin_unlock(&ctl->tree_lock);
2485 break;
2486 }
2487
2488 if (entry->bitmap) {
2489 ret = search_bitmap(ctl, entry, &start, &bytes);
2490 if (!ret) {
2491 if (start >= end) {
2492 spin_unlock(&ctl->tree_lock);
2493 break;
2494 }
2495 bytes = min(bytes, end - start);
2496 bitmap_clear_bits(ctl, entry, start, bytes);
2497 if (entry->bytes == 0)
2498 free_bitmap(ctl, entry);
2499 } else {
2500 start = entry->offset + BITS_PER_BITMAP *
2501 block_group->sectorsize;
2502 spin_unlock(&ctl->tree_lock);
2503 ret = 0;
2504 continue;
2505 }
2506 } else {
2507 start = entry->offset;
2508 bytes = min(entry->bytes, end - start);
2509 unlink_free_space(ctl, entry);
2510 kmem_cache_free(btrfs_free_space_cachep, entry);
2511 }
2512
2513 spin_unlock(&ctl->tree_lock);
2514
2515 if (bytes >= minlen) {
2516 int update_ret;
2517 update_ret = btrfs_update_reserved_bytes(block_group,
2518 bytes, 1, 1);
2519
2520 ret = btrfs_error_discard_extent(fs_info->extent_root,
2521 start,
2522 bytes,
2523 &actually_trimmed);
2524
2525 btrfs_add_free_space(block_group, start, bytes);
2526 if (!update_ret)
2527 btrfs_update_reserved_bytes(block_group,
2528 bytes, 0, 1);
2529
2530 if (ret)
2531 break;
2532 *trimmed += actually_trimmed;
2533 }
2534 start += bytes;
2535 bytes = 0;
2536
2537 if (fatal_signal_pending(current)) {
2538 ret = -ERESTARTSYS;
2539 break;
2540 }
2541
2542 cond_resched();
2543 }
2544
2545 return ret;
2546 }
2547
2548 /*
2549 * Find the left-most item in the cache tree, and then return the
2550 * smallest inode number in the item.
2551 *
2552 * Note: the returned inode number may not be the smallest one in
2553 * the tree, if the left-most item is a bitmap.
2554 */
2555 u64 btrfs_find_ino_for_alloc(struct btrfs_root *fs_root)
2556 {
2557 struct btrfs_free_space_ctl *ctl = fs_root->free_ino_ctl;
2558 struct btrfs_free_space *entry = NULL;
2559 u64 ino = 0;
2560
2561 spin_lock(&ctl->tree_lock);
2562
2563 if (RB_EMPTY_ROOT(&ctl->free_space_offset))
2564 goto out;
2565
2566 entry = rb_entry(rb_first(&ctl->free_space_offset),
2567 struct btrfs_free_space, offset_index);
2568
2569 if (!entry->bitmap) {
2570 ino = entry->offset;
2571
2572 unlink_free_space(ctl, entry);
2573 entry->offset++;
2574 entry->bytes--;
2575 if (!entry->bytes)
2576 kmem_cache_free(btrfs_free_space_cachep, entry);
2577 else
2578 link_free_space(ctl, entry);
2579 } else {
2580 u64 offset = 0;
2581 u64 count = 1;
2582 int ret;
2583
2584 ret = search_bitmap(ctl, entry, &offset, &count);
2585 BUG_ON(ret);
2586
2587 ino = offset;
2588 bitmap_clear_bits(ctl, entry, offset, 1);
2589 if (entry->bytes == 0)
2590 free_bitmap(ctl, entry);
2591 }
2592 out:
2593 spin_unlock(&ctl->tree_lock);
2594
2595 return ino;
2596 }
2597
2598 struct inode *lookup_free_ino_inode(struct btrfs_root *root,
2599 struct btrfs_path *path)
2600 {
2601 struct inode *inode = NULL;
2602
2603 spin_lock(&root->cache_lock);
2604 if (root->cache_inode)
2605 inode = igrab(root->cache_inode);
2606 spin_unlock(&root->cache_lock);
2607 if (inode)
2608 return inode;
2609
2610 inode = __lookup_free_space_inode(root, path, 0);
2611 if (IS_ERR(inode))
2612 return inode;
2613
2614 spin_lock(&root->cache_lock);
2615 if (!btrfs_fs_closing(root->fs_info))
2616 root->cache_inode = igrab(inode);
2617 spin_unlock(&root->cache_lock);
2618
2619 return inode;
2620 }
2621
2622 int create_free_ino_inode(struct btrfs_root *root,
2623 struct btrfs_trans_handle *trans,
2624 struct btrfs_path *path)
2625 {
2626 return __create_free_space_inode(root, trans, path,
2627 BTRFS_FREE_INO_OBJECTID, 0);
2628 }
2629
2630 int load_free_ino_cache(struct btrfs_fs_info *fs_info, struct btrfs_root *root)
2631 {
2632 struct btrfs_free_space_ctl *ctl = root->free_ino_ctl;
2633 struct btrfs_path *path;
2634 struct inode *inode;
2635 int ret = 0;
2636 u64 root_gen = btrfs_root_generation(&root->root_item);
2637
2638 if (!btrfs_test_opt(root, INODE_MAP_CACHE))
2639 return 0;
2640
2641 /*
2642 * If we're unmounting then just return, since this does a search on the
2643 * normal root and not the commit root and we could deadlock.
2644 */
2645 if (btrfs_fs_closing(fs_info))
2646 return 0;
2647
2648 path = btrfs_alloc_path();
2649 if (!path)
2650 return 0;
2651
2652 inode = lookup_free_ino_inode(root, path);
2653 if (IS_ERR(inode))
2654 goto out;
2655
2656 if (root_gen != BTRFS_I(inode)->generation)
2657 goto out_put;
2658
2659 ret = __load_free_space_cache(root, inode, ctl, path, 0);
2660
2661 if (ret < 0)
2662 printk(KERN_ERR "btrfs: failed to load free ino cache for "
2663 "root %llu\n", root->root_key.objectid);
2664 out_put:
2665 iput(inode);
2666 out:
2667 btrfs_free_path(path);
2668 return ret;
2669 }
2670
2671 int btrfs_write_out_ino_cache(struct btrfs_root *root,
2672 struct btrfs_trans_handle *trans,
2673 struct btrfs_path *path)
2674 {
2675 struct btrfs_free_space_ctl *ctl = root->free_ino_ctl;
2676 struct inode *inode;
2677 int ret;
2678
2679 if (!btrfs_test_opt(root, INODE_MAP_CACHE))
2680 return 0;
2681
2682 inode = lookup_free_ino_inode(root, path);
2683 if (IS_ERR(inode))
2684 return 0;
2685
2686 ret = __btrfs_write_out_cache(root, inode, ctl, NULL, trans, path, 0);
2687 if (ret < 0)
2688 printk(KERN_ERR "btrfs: failed to write free ino cache "
2689 "for root %llu\n", root->root_key.objectid);
2690
2691 iput(inode);
2692 return ret;
2693 }
Linux with added FPC-III support