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Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux...
[linux-2.6.git] / fs / btrfs / free-space-cache.c
blobd20ff87ca603bba8255b04a95f34d11bb385ab33
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 <linux/ratelimit.h>
24 #include "ctree.h"
25 #include "free-space-cache.h"
26 #include "transaction.h"
27 #include "disk-io.h"
28 #include "extent_io.h"
29 #include "inode-map.h"
30
31 #define BITS_PER_BITMAP (PAGE_CACHE_SIZE * 8)
32 #define MAX_CACHE_BYTES_PER_GIG (32 * 1024)
33
34 static int link_free_space(struct btrfs_free_space_ctl *ctl,
35 struct btrfs_free_space *info);
36
37 static struct inode *__lookup_free_space_inode(struct btrfs_root *root,
38 struct btrfs_path *path,
39 u64 offset)
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 key.objectid = BTRFS_FREE_SPACE_OBJECTID;
50 key.offset = offset;
51 key.type = 0;
52
53 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
54 if (ret < 0)
55 return ERR_PTR(ret);
56 if (ret > 0) {
57 btrfs_release_path(path);
58 return ERR_PTR(-ENOENT);
59 }
60
61 leaf = path->nodes[0];
62 header = btrfs_item_ptr(leaf, path->slots[0],
63 struct btrfs_free_space_header);
64 btrfs_free_space_key(leaf, header, &disk_key);
65 btrfs_disk_key_to_cpu(&location, &disk_key);
66 btrfs_release_path(path);
67
68 inode = btrfs_iget(root->fs_info->sb, &location, root, NULL);
69 if (!inode)
70 return ERR_PTR(-ENOENT);
71 if (IS_ERR(inode))
72 return inode;
73 if (is_bad_inode(inode)) {
74 iput(inode);
75 return ERR_PTR(-ENOENT);
76 }
77
78 inode->i_mapping->flags &= ~__GFP_FS;
79
80 return inode;
81 }
82
83 struct inode *lookup_free_space_inode(struct btrfs_root *root,
84 struct btrfs_block_group_cache
85 *block_group, struct btrfs_path *path)
86 {
87 struct inode *inode = NULL;
88 u32 flags = BTRFS_INODE_NODATASUM | BTRFS_INODE_NODATACOW;
89
90 spin_lock(&block_group->lock);
91 if (block_group->inode)
92 inode = igrab(block_group->inode);
93 spin_unlock(&block_group->lock);
94 if (inode)
95 return inode;
96
97 inode = __lookup_free_space_inode(root, path,
98 block_group->key.objectid);
99 if (IS_ERR(inode))
100 return inode;
101
102 spin_lock(&block_group->lock);
103 if (!((BTRFS_I(inode)->flags & flags) == flags)) {
104 printk(KERN_INFO "Old style space inode found, converting.\n");
105 BTRFS_I(inode)->flags |= BTRFS_INODE_NODATASUM |
106 BTRFS_INODE_NODATACOW;
107 block_group->disk_cache_state = BTRFS_DC_CLEAR;
108 }
109
110 if (!block_group->iref) {
111 block_group->inode = igrab(inode);
112 block_group->iref = 1;
113 }
114 spin_unlock(&block_group->lock);
115
116 return inode;
117 }
118
119 int __create_free_space_inode(struct btrfs_root *root,
120 struct btrfs_trans_handle *trans,
121 struct btrfs_path *path, u64 ino, u64 offset)
122 {
123 struct btrfs_key key;
124 struct btrfs_disk_key disk_key;
125 struct btrfs_free_space_header *header;
126 struct btrfs_inode_item *inode_item;
127 struct extent_buffer *leaf;
128 u64 flags = BTRFS_INODE_NOCOMPRESS | BTRFS_INODE_PREALLOC;
129 int ret;
130
131 ret = btrfs_insert_empty_inode(trans, root, path, ino);
132 if (ret)
133 return ret;
134
135 /* We inline crc's for the free disk space cache */
136 if (ino != BTRFS_FREE_INO_OBJECTID)
137 flags |= BTRFS_INODE_NODATASUM | BTRFS_INODE_NODATACOW;
138
139 leaf = path->nodes[0];
140 inode_item = btrfs_item_ptr(leaf, path->slots[0],
141 struct btrfs_inode_item);
142 btrfs_item_key(leaf, &disk_key, path->slots[0]);
143 memset_extent_buffer(leaf, 0, (unsigned long)inode_item,
144 sizeof(*inode_item));
145 btrfs_set_inode_generation(leaf, inode_item, trans->transid);
146 btrfs_set_inode_size(leaf, inode_item, 0);
147 btrfs_set_inode_nbytes(leaf, inode_item, 0);
148 btrfs_set_inode_uid(leaf, inode_item, 0);
149 btrfs_set_inode_gid(leaf, inode_item, 0);
150 btrfs_set_inode_mode(leaf, inode_item, S_IFREG | 0600);
151 btrfs_set_inode_flags(leaf, inode_item, flags);
152 btrfs_set_inode_nlink(leaf, inode_item, 1);
153 btrfs_set_inode_transid(leaf, inode_item, trans->transid);
154 btrfs_set_inode_block_group(leaf, inode_item, offset);
155 btrfs_mark_buffer_dirty(leaf);
156 btrfs_release_path(path);
157
158 key.objectid = BTRFS_FREE_SPACE_OBJECTID;
159 key.offset = offset;
160 key.type = 0;
161
162 ret = btrfs_insert_empty_item(trans, root, path, &key,
163 sizeof(struct btrfs_free_space_header));
164 if (ret < 0) {
165 btrfs_release_path(path);
166 return ret;
167 }
168 leaf = path->nodes[0];
169 header = btrfs_item_ptr(leaf, path->slots[0],
170 struct btrfs_free_space_header);
171 memset_extent_buffer(leaf, 0, (unsigned long)header, sizeof(*header));
172 btrfs_set_free_space_key(leaf, header, &disk_key);
173 btrfs_mark_buffer_dirty(leaf);
174 btrfs_release_path(path);
175
176 return 0;
177 }
178
179 int create_free_space_inode(struct btrfs_root *root,
180 struct btrfs_trans_handle *trans,
181 struct btrfs_block_group_cache *block_group,
182 struct btrfs_path *path)
183 {
184 int ret;
185 u64 ino;
186
187 ret = btrfs_find_free_objectid(root, &ino);
188 if (ret < 0)
189 return ret;
190
191 return __create_free_space_inode(root, trans, path, ino,
192 block_group->key.objectid);
193 }
194
195 int btrfs_truncate_free_space_cache(struct btrfs_root *root,
196 struct btrfs_trans_handle *trans,
197 struct btrfs_path *path,
198 struct inode *inode)
199 {
200 struct btrfs_block_rsv *rsv;
201 u64 needed_bytes;
202 loff_t oldsize;
203 int ret = 0;
204
205 rsv = trans->block_rsv;
206 trans->block_rsv = &root->fs_info->global_block_rsv;
207
208 /* 1 for slack space, 1 for updating the inode */
209 needed_bytes = btrfs_calc_trunc_metadata_size(root, 1) +
210 btrfs_calc_trans_metadata_size(root, 1);
211
212 spin_lock(&trans->block_rsv->lock);
213 if (trans->block_rsv->reserved < needed_bytes) {
214 spin_unlock(&trans->block_rsv->lock);
215 trans->block_rsv = rsv;
216 return -ENOSPC;
217 }
218 spin_unlock(&trans->block_rsv->lock);
219
220 oldsize = i_size_read(inode);
221 btrfs_i_size_write(inode, 0);
222 truncate_pagecache(inode, oldsize, 0);
223
224 /*
225 * We don't need an orphan item because truncating the free space cache
226 * will never be split across transactions.
227 */
228 ret = btrfs_truncate_inode_items(trans, root, inode,
229 0, BTRFS_EXTENT_DATA_KEY);
230
231 if (ret) {
232 trans->block_rsv = rsv;
233 WARN_ON(1);
234 return ret;
235 }
236
237 ret = btrfs_update_inode(trans, root, inode);
238 trans->block_rsv = rsv;
239
240 return ret;
241 }
242
243 static int readahead_cache(struct inode *inode)
244 {
245 struct file_ra_state *ra;
246 unsigned long last_index;
247
248 ra = kzalloc(sizeof(*ra), GFP_NOFS);
249 if (!ra)
250 return -ENOMEM;
251
252 file_ra_state_init(ra, inode->i_mapping);
253 last_index = (i_size_read(inode) - 1) >> PAGE_CACHE_SHIFT;
254
255 page_cache_sync_readahead(inode->i_mapping, ra, NULL, 0, last_index);
256
257 kfree(ra);
258
259 return 0;
260 }
261
262 struct io_ctl {
263 void *cur, *orig;
264 struct page *page;
265 struct page **pages;
266 struct btrfs_root *root;
267 unsigned long size;
268 int index;
269 int num_pages;
270 unsigned check_crcs:1;
271 };
272
273 static int io_ctl_init(struct io_ctl *io_ctl, struct inode *inode,
274 struct btrfs_root *root)
275 {
276 memset(io_ctl, 0, sizeof(struct io_ctl));
277 io_ctl->num_pages = (i_size_read(inode) + PAGE_CACHE_SIZE - 1) >>
278 PAGE_CACHE_SHIFT;
279 io_ctl->pages = kzalloc(sizeof(struct page *) * io_ctl->num_pages,
280 GFP_NOFS);
281 if (!io_ctl->pages)
282 return -ENOMEM;
283 io_ctl->root = root;
284 if (btrfs_ino(inode) != BTRFS_FREE_INO_OBJECTID)
285 io_ctl->check_crcs = 1;
286 return 0;
287 }
288
289 static void io_ctl_free(struct io_ctl *io_ctl)
290 {
291 kfree(io_ctl->pages);
292 }
293
294 static void io_ctl_unmap_page(struct io_ctl *io_ctl)
295 {
296 if (io_ctl->cur) {
297 kunmap(io_ctl->page);
298 io_ctl->cur = NULL;
299 io_ctl->orig = NULL;
300 }
301 }
302
303 static void io_ctl_map_page(struct io_ctl *io_ctl, int clear)
304 {
305 WARN_ON(io_ctl->cur);
306 BUG_ON(io_ctl->index >= io_ctl->num_pages);
307 io_ctl->page = io_ctl->pages[io_ctl->index++];
308 io_ctl->cur = kmap(io_ctl->page);
309 io_ctl->orig = io_ctl->cur;
310 io_ctl->size = PAGE_CACHE_SIZE;
311 if (clear)
312 memset(io_ctl->cur, 0, PAGE_CACHE_SIZE);
313 }
314
315 static void io_ctl_drop_pages(struct io_ctl *io_ctl)
316 {
317 int i;
318
319 io_ctl_unmap_page(io_ctl);
320
321 for (i = 0; i < io_ctl->num_pages; i++) {
322 if (io_ctl->pages[i]) {
323 ClearPageChecked(io_ctl->pages[i]);
324 unlock_page(io_ctl->pages[i]);
325 page_cache_release(io_ctl->pages[i]);
326 }
327 }
328 }
329
330 static int io_ctl_prepare_pages(struct io_ctl *io_ctl, struct inode *inode,
331 int uptodate)
332 {
333 struct page *page;
334 gfp_t mask = btrfs_alloc_write_mask(inode->i_mapping);
335 int i;
336
337 for (i = 0; i < io_ctl->num_pages; i++) {
338 page = find_or_create_page(inode->i_mapping, i, mask);
339 if (!page) {
340 io_ctl_drop_pages(io_ctl);
341 return -ENOMEM;
342 }
343 io_ctl->pages[i] = page;
344 if (uptodate && !PageUptodate(page)) {
345 btrfs_readpage(NULL, page);
346 lock_page(page);
347 if (!PageUptodate(page)) {
348 printk(KERN_ERR "btrfs: error reading free "
349 "space cache\n");
350 io_ctl_drop_pages(io_ctl);
351 return -EIO;
352 }
353 }
354 }
355
356 for (i = 0; i < io_ctl->num_pages; i++) {
357 clear_page_dirty_for_io(io_ctl->pages[i]);
358 set_page_extent_mapped(io_ctl->pages[i]);
359 }
360
361 return 0;
362 }
363
364 static void io_ctl_set_generation(struct io_ctl *io_ctl, u64 generation)
365 {
366 u64 *val;
367
368 io_ctl_map_page(io_ctl, 1);
369
370 /*
371 * Skip the csum areas. If we don't check crcs then we just have a
372 * 64bit chunk at the front of the first page.
373 */
374 if (io_ctl->check_crcs) {
375 io_ctl->cur += (sizeof(u32) * io_ctl->num_pages);
376 io_ctl->size -= sizeof(u64) + (sizeof(u32) * io_ctl->num_pages);
377 } else {
378 io_ctl->cur += sizeof(u64);
379 io_ctl->size -= sizeof(u64) * 2;
380 }
381
382 val = io_ctl->cur;
383 *val = cpu_to_le64(generation);
384 io_ctl->cur += sizeof(u64);
385 }
386
387 static int io_ctl_check_generation(struct io_ctl *io_ctl, u64 generation)
388 {
389 u64 *gen;
390
391 /*
392 * Skip the crc area. If we don't check crcs then we just have a 64bit
393 * chunk at the front of the first page.
394 */
395 if (io_ctl->check_crcs) {
396 io_ctl->cur += sizeof(u32) * io_ctl->num_pages;
397 io_ctl->size -= sizeof(u64) +
398 (sizeof(u32) * io_ctl->num_pages);
399 } else {
400 io_ctl->cur += sizeof(u64);
401 io_ctl->size -= sizeof(u64) * 2;
402 }
403
404 gen = io_ctl->cur;
405 if (le64_to_cpu(*gen) != generation) {
406 printk_ratelimited(KERN_ERR "btrfs: space cache generation "
407 "(%Lu) does not match inode (%Lu)\n", *gen,
408 generation);
409 io_ctl_unmap_page(io_ctl);
410 return -EIO;
411 }
412 io_ctl->cur += sizeof(u64);
413 return 0;
414 }
415
416 static void io_ctl_set_crc(struct io_ctl *io_ctl, int index)
417 {
418 u32 *tmp;
419 u32 crc = ~(u32)0;
420 unsigned offset = 0;
421
422 if (!io_ctl->check_crcs) {
423 io_ctl_unmap_page(io_ctl);
424 return;
425 }
426
427 if (index == 0)
428 offset = sizeof(u32) * io_ctl->num_pages;
429
430 crc = btrfs_csum_data(io_ctl->root, io_ctl->orig + offset, crc,
431 PAGE_CACHE_SIZE - offset);
432 btrfs_csum_final(crc, (char *)&crc);
433 io_ctl_unmap_page(io_ctl);
434 tmp = kmap(io_ctl->pages[0]);
435 tmp += index;
436 *tmp = crc;
437 kunmap(io_ctl->pages[0]);
438 }
439
440 static int io_ctl_check_crc(struct io_ctl *io_ctl, int index)
441 {
442 u32 *tmp, val;
443 u32 crc = ~(u32)0;
444 unsigned offset = 0;
445
446 if (!io_ctl->check_crcs) {
447 io_ctl_map_page(io_ctl, 0);
448 return 0;
449 }
450
451 if (index == 0)
452 offset = sizeof(u32) * io_ctl->num_pages;
453
454 tmp = kmap(io_ctl->pages[0]);
455 tmp += index;
456 val = *tmp;
457 kunmap(io_ctl->pages[0]);
458
459 io_ctl_map_page(io_ctl, 0);
460 crc = btrfs_csum_data(io_ctl->root, io_ctl->orig + offset, crc,
461 PAGE_CACHE_SIZE - offset);
462 btrfs_csum_final(crc, (char *)&crc);
463 if (val != crc) {
464 printk_ratelimited(KERN_ERR "btrfs: csum mismatch on free "
465 "space cache\n");
466 io_ctl_unmap_page(io_ctl);
467 return -EIO;
468 }
469
470 return 0;
471 }
472
473 static int io_ctl_add_entry(struct io_ctl *io_ctl, u64 offset, u64 bytes,
474 void *bitmap)
475 {
476 struct btrfs_free_space_entry *entry;
477
478 if (!io_ctl->cur)
479 return -ENOSPC;
480
481 entry = io_ctl->cur;
482 entry->offset = cpu_to_le64(offset);
483 entry->bytes = cpu_to_le64(bytes);
484 entry->type = (bitmap) ? BTRFS_FREE_SPACE_BITMAP :
485 BTRFS_FREE_SPACE_EXTENT;
486 io_ctl->cur += sizeof(struct btrfs_free_space_entry);
487 io_ctl->size -= sizeof(struct btrfs_free_space_entry);
488
489 if (io_ctl->size >= sizeof(struct btrfs_free_space_entry))
490 return 0;
491
492 io_ctl_set_crc(io_ctl, io_ctl->index - 1);
493
494 /* No more pages to map */
495 if (io_ctl->index >= io_ctl->num_pages)
496 return 0;
497
498 /* map the next page */
499 io_ctl_map_page(io_ctl, 1);
500 return 0;
501 }
502
503 static int io_ctl_add_bitmap(struct io_ctl *io_ctl, void *bitmap)
504 {
505 if (!io_ctl->cur)
506 return -ENOSPC;
507
508 /*
509 * If we aren't at the start of the current page, unmap this one and
510 * map the next one if there is any left.
511 */
512 if (io_ctl->cur != io_ctl->orig) {
513 io_ctl_set_crc(io_ctl, io_ctl->index - 1);
514 if (io_ctl->index >= io_ctl->num_pages)
515 return -ENOSPC;
516 io_ctl_map_page(io_ctl, 0);
517 }
518
519 memcpy(io_ctl->cur, bitmap, PAGE_CACHE_SIZE);
520 io_ctl_set_crc(io_ctl, io_ctl->index - 1);
521 if (io_ctl->index < io_ctl->num_pages)
522 io_ctl_map_page(io_ctl, 0);
523 return 0;
524 }
525
526 static void io_ctl_zero_remaining_pages(struct io_ctl *io_ctl)
527 {
528 /*
529 * If we're not on the boundary we know we've modified the page and we
530 * need to crc the page.
531 */
532 if (io_ctl->cur != io_ctl->orig)
533 io_ctl_set_crc(io_ctl, io_ctl->index - 1);
534 else
535 io_ctl_unmap_page(io_ctl);
536
537 while (io_ctl->index < io_ctl->num_pages) {
538 io_ctl_map_page(io_ctl, 1);
539 io_ctl_set_crc(io_ctl, io_ctl->index - 1);
540 }
541 }
542
543 static int io_ctl_read_entry(struct io_ctl *io_ctl,
544 struct btrfs_free_space *entry, u8 *type)
545 {
546 struct btrfs_free_space_entry *e;
547 int ret;
548
549 if (!io_ctl->cur) {
550 ret = io_ctl_check_crc(io_ctl, io_ctl->index);
551 if (ret)
552 return ret;
553 }
554
555 e = io_ctl->cur;
556 entry->offset = le64_to_cpu(e->offset);
557 entry->bytes = le64_to_cpu(e->bytes);
558 *type = e->type;
559 io_ctl->cur += sizeof(struct btrfs_free_space_entry);
560 io_ctl->size -= sizeof(struct btrfs_free_space_entry);
561
562 if (io_ctl->size >= sizeof(struct btrfs_free_space_entry))
563 return 0;
564
565 io_ctl_unmap_page(io_ctl);
566
567 return 0;
568 }
569
570 static int io_ctl_read_bitmap(struct io_ctl *io_ctl,
571 struct btrfs_free_space *entry)
572 {
573 int ret;
574
575 ret = io_ctl_check_crc(io_ctl, io_ctl->index);
576 if (ret)
577 return ret;
578
579 memcpy(entry->bitmap, io_ctl->cur, PAGE_CACHE_SIZE);
580 io_ctl_unmap_page(io_ctl);
581
582 return 0;
583 }
584
585 int __load_free_space_cache(struct btrfs_root *root, struct inode *inode,
586 struct btrfs_free_space_ctl *ctl,
587 struct btrfs_path *path, u64 offset)
588 {
589 struct btrfs_free_space_header *header;
590 struct extent_buffer *leaf;
591 struct io_ctl io_ctl;
592 struct btrfs_key key;
593 struct btrfs_free_space *e, *n;
594 struct list_head bitmaps;
595 u64 num_entries;
596 u64 num_bitmaps;
597 u64 generation;
598 u8 type;
599 int ret = 0;
600
601 INIT_LIST_HEAD(&bitmaps);
602
603 /* Nothing in the space cache, goodbye */
604 if (!i_size_read(inode))
605 return 0;
606
607 key.objectid = BTRFS_FREE_SPACE_OBJECTID;
608 key.offset = offset;
609 key.type = 0;
610
611 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
612 if (ret < 0)
613 return 0;
614 else if (ret > 0) {
615 btrfs_release_path(path);
616 return 0;
617 }
618
619 ret = -1;
620
621 leaf = path->nodes[0];
622 header = btrfs_item_ptr(leaf, path->slots[0],
623 struct btrfs_free_space_header);
624 num_entries = btrfs_free_space_entries(leaf, header);
625 num_bitmaps = btrfs_free_space_bitmaps(leaf, header);
626 generation = btrfs_free_space_generation(leaf, header);
627 btrfs_release_path(path);
628
629 if (BTRFS_I(inode)->generation != generation) {
630 printk(KERN_ERR "btrfs: free space inode generation (%llu) did"
631 " not match free space cache generation (%llu)\n",
632 (unsigned long long)BTRFS_I(inode)->generation,
633 (unsigned long long)generation);
634 return 0;
635 }
636
637 if (!num_entries)
638 return 0;
639
640 ret = io_ctl_init(&io_ctl, inode, root);
641 if (ret)
642 return ret;
643
644 ret = readahead_cache(inode);
645 if (ret)
646 goto out;
647
648 ret = io_ctl_prepare_pages(&io_ctl, inode, 1);
649 if (ret)
650 goto out;
651
652 ret = io_ctl_check_crc(&io_ctl, 0);
653 if (ret)
654 goto free_cache;
655
656 ret = io_ctl_check_generation(&io_ctl, generation);
657 if (ret)
658 goto free_cache;
659
660 while (num_entries) {
661 e = kmem_cache_zalloc(btrfs_free_space_cachep,
662 GFP_NOFS);
663 if (!e)
664 goto free_cache;
665
666 ret = io_ctl_read_entry(&io_ctl, e, &type);
667 if (ret) {
668 kmem_cache_free(btrfs_free_space_cachep, e);
669 goto free_cache;
670 }
671
672 if (!e->bytes) {
673 kmem_cache_free(btrfs_free_space_cachep, e);
674 goto free_cache;
675 }
676
677 if (type == BTRFS_FREE_SPACE_EXTENT) {
678 spin_lock(&ctl->tree_lock);
679 ret = link_free_space(ctl, e);
680 spin_unlock(&ctl->tree_lock);
681 if (ret) {
682 printk(KERN_ERR "Duplicate entries in "
683 "free space cache, dumping\n");
684 kmem_cache_free(btrfs_free_space_cachep, e);
685 goto free_cache;
686 }
687 } else {
688 BUG_ON(!num_bitmaps);
689 num_bitmaps--;
690 e->bitmap = kzalloc(PAGE_CACHE_SIZE, GFP_NOFS);
691 if (!e->bitmap) {
692 kmem_cache_free(
693 btrfs_free_space_cachep, e);
694 goto free_cache;
695 }
696 spin_lock(&ctl->tree_lock);
697 ret = link_free_space(ctl, e);
698 ctl->total_bitmaps++;
699 ctl->op->recalc_thresholds(ctl);
700 spin_unlock(&ctl->tree_lock);
701 if (ret) {
702 printk(KERN_ERR "Duplicate entries in "
703 "free space cache, dumping\n");
704 kmem_cache_free(btrfs_free_space_cachep, e);
705 goto free_cache;
706 }
707 list_add_tail(&e->list, &bitmaps);
708 }
709
710 num_entries--;
711 }
712
713 io_ctl_unmap_page(&io_ctl);
714
715 /*
716 * We add the bitmaps at the end of the entries in order that
717 * the bitmap entries are added to the cache.
718 */
719 list_for_each_entry_safe(e, n, &bitmaps, list) {
720 list_del_init(&e->list);
721 ret = io_ctl_read_bitmap(&io_ctl, e);
722 if (ret)
723 goto free_cache;
724 }
725
726 io_ctl_drop_pages(&io_ctl);
727 ret = 1;
728 out:
729 io_ctl_free(&io_ctl);
730 return ret;
731 free_cache:
732 io_ctl_drop_pages(&io_ctl);
733 __btrfs_remove_free_space_cache(ctl);
734 goto out;
735 }
736
737 int load_free_space_cache(struct btrfs_fs_info *fs_info,
738 struct btrfs_block_group_cache *block_group)
739 {
740 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
741 struct btrfs_root *root = fs_info->tree_root;
742 struct inode *inode;
743 struct btrfs_path *path;
744 int ret = 0;
745 bool matched;
746 u64 used = btrfs_block_group_used(&block_group->item);
747
748 /*
749 * If we're unmounting then just return, since this does a search on the
750 * normal root and not the commit root and we could deadlock.
751 */
752 if (btrfs_fs_closing(fs_info))
753 return 0;
754
755 /*
756 * If this block group has been marked to be cleared for one reason or
757 * another then we can't trust the on disk cache, so just return.
758 */
759 spin_lock(&block_group->lock);
760 if (block_group->disk_cache_state != BTRFS_DC_WRITTEN) {
761 spin_unlock(&block_group->lock);
762 return 0;
763 }
764 spin_unlock(&block_group->lock);
765
766 path = btrfs_alloc_path();
767 if (!path)
768 return 0;
769
770 inode = lookup_free_space_inode(root, block_group, path);
771 if (IS_ERR(inode)) {
772 btrfs_free_path(path);
773 return 0;
774 }
775
776 /* We may have converted the inode and made the cache invalid. */
777 spin_lock(&block_group->lock);
778 if (block_group->disk_cache_state != BTRFS_DC_WRITTEN) {
779 spin_unlock(&block_group->lock);
780 goto out;
781 }
782 spin_unlock(&block_group->lock);
783
784 ret = __load_free_space_cache(fs_info->tree_root, inode, ctl,
785 path, block_group->key.objectid);
786 btrfs_free_path(path);
787 if (ret <= 0)
788 goto out;
789
790 spin_lock(&ctl->tree_lock);
791 matched = (ctl->free_space == (block_group->key.offset - used -
792 block_group->bytes_super));
793 spin_unlock(&ctl->tree_lock);
794
795 if (!matched) {
796 __btrfs_remove_free_space_cache(ctl);
797 printk(KERN_ERR "block group %llu has an wrong amount of free "
798 "space\n", block_group->key.objectid);
799 ret = -1;
800 }
801 out:
802 if (ret < 0) {
803 /* This cache is bogus, make sure it gets cleared */
804 spin_lock(&block_group->lock);
805 block_group->disk_cache_state = BTRFS_DC_CLEAR;
806 spin_unlock(&block_group->lock);
807 ret = 0;
808
809 printk(KERN_ERR "btrfs: failed to load free space cache "
810 "for block group %llu\n", block_group->key.objectid);
811 }
812
813 iput(inode);
814 return ret;
815 }
816
817 /**
818 * __btrfs_write_out_cache - write out cached info to an inode
819 * @root - the root the inode belongs to
820 * @ctl - the free space cache we are going to write out
821 * @block_group - the block_group for this cache if it belongs to a block_group
822 * @trans - the trans handle
823 * @path - the path to use
824 * @offset - the offset for the key we'll insert
825 *
826 * This function writes out a free space cache struct to disk for quick recovery
827 * on mount. This will return 0 if it was successfull in writing the cache out,
828 * and -1 if it was not.
829 */
830 int __btrfs_write_out_cache(struct btrfs_root *root, struct inode *inode,
831 struct btrfs_free_space_ctl *ctl,
832 struct btrfs_block_group_cache *block_group,
833 struct btrfs_trans_handle *trans,
834 struct btrfs_path *path, u64 offset)
835 {
836 struct btrfs_free_space_header *header;
837 struct extent_buffer *leaf;
838 struct rb_node *node;
839 struct list_head *pos, *n;
840 struct extent_state *cached_state = NULL;
841 struct btrfs_free_cluster *cluster = NULL;
842 struct extent_io_tree *unpin = NULL;
843 struct io_ctl io_ctl;
844 struct list_head bitmap_list;
845 struct btrfs_key key;
846 u64 start, extent_start, extent_end, len;
847 int entries = 0;
848 int bitmaps = 0;
849 int ret;
850 int err = -1;
851
852 INIT_LIST_HEAD(&bitmap_list);
853
854 if (!i_size_read(inode))
855 return -1;
856
857 ret = io_ctl_init(&io_ctl, inode, root);
858 if (ret)
859 return -1;
860
861 /* Get the cluster for this block_group if it exists */
862 if (block_group && !list_empty(&block_group->cluster_list))
863 cluster = list_entry(block_group->cluster_list.next,
864 struct btrfs_free_cluster,
865 block_group_list);
866
867 /* Lock all pages first so we can lock the extent safely. */
868 io_ctl_prepare_pages(&io_ctl, inode, 0);
869
870 lock_extent_bits(&BTRFS_I(inode)->io_tree, 0, i_size_read(inode) - 1,
871 0, &cached_state, GFP_NOFS);
872
873 node = rb_first(&ctl->free_space_offset);
874 if (!node && cluster) {
875 node = rb_first(&cluster->root);
876 cluster = NULL;
877 }
878
879 /* Make sure we can fit our crcs into the first page */
880 if (io_ctl.check_crcs &&
881 (io_ctl.num_pages * sizeof(u32)) >= PAGE_CACHE_SIZE) {
882 WARN_ON(1);
883 goto out_nospc;
884 }
885
886 io_ctl_set_generation(&io_ctl, trans->transid);
887
888 /* Write out the extent entries */
889 while (node) {
890 struct btrfs_free_space *e;
891
892 e = rb_entry(node, struct btrfs_free_space, offset_index);
893 entries++;
894
895 ret = io_ctl_add_entry(&io_ctl, e->offset, e->bytes,
896 e->bitmap);
897 if (ret)
898 goto out_nospc;
899
900 if (e->bitmap) {
901 list_add_tail(&e->list, &bitmap_list);
902 bitmaps++;
903 }
904 node = rb_next(node);
905 if (!node && cluster) {
906 node = rb_first(&cluster->root);
907 cluster = NULL;
908 }
909 }
910
911 /*
912 * We want to add any pinned extents to our free space cache
913 * so we don't leak the space
914 */
915
916 /*
917 * We shouldn't have switched the pinned extents yet so this is the
918 * right one
919 */
920 unpin = root->fs_info->pinned_extents;
921
922 if (block_group)
923 start = block_group->key.objectid;
924
925 while (block_group && (start < block_group->key.objectid +
926 block_group->key.offset)) {
927 ret = find_first_extent_bit(unpin, start,
928 &extent_start, &extent_end,
929 EXTENT_DIRTY);
930 if (ret) {
931 ret = 0;
932 break;
933 }
934
935 /* This pinned extent is out of our range */
936 if (extent_start >= block_group->key.objectid +
937 block_group->key.offset)
938 break;
939
940 extent_start = max(extent_start, start);
941 extent_end = min(block_group->key.objectid +
942 block_group->key.offset, extent_end + 1);
943 len = extent_end - extent_start;
944
945 entries++;
946 ret = io_ctl_add_entry(&io_ctl, extent_start, len, NULL);
947 if (ret)
948 goto out_nospc;
949
950 start = extent_end;
951 }
952
953 /* Write out the bitmaps */
954 list_for_each_safe(pos, n, &bitmap_list) {
955 struct btrfs_free_space *entry =
956 list_entry(pos, struct btrfs_free_space, list);
957
958 ret = io_ctl_add_bitmap(&io_ctl, entry->bitmap);
959 if (ret)
960 goto out_nospc;
961 list_del_init(&entry->list);
962 }
963
964 /* Zero out the rest of the pages just to make sure */
965 io_ctl_zero_remaining_pages(&io_ctl);
966
967 ret = btrfs_dirty_pages(root, inode, io_ctl.pages, io_ctl.num_pages,
968 0, i_size_read(inode), &cached_state);
969 io_ctl_drop_pages(&io_ctl);
970 unlock_extent_cached(&BTRFS_I(inode)->io_tree, 0,
971 i_size_read(inode) - 1, &cached_state, GFP_NOFS);
972
973 if (ret)
974 goto out;
975
976
977 ret = filemap_write_and_wait(inode->i_mapping);
978 if (ret)
979 goto out;
980
981 key.objectid = BTRFS_FREE_SPACE_OBJECTID;
982 key.offset = offset;
983 key.type = 0;
984
985 ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
986 if (ret < 0) {
987 clear_extent_bit(&BTRFS_I(inode)->io_tree, 0, inode->i_size - 1,
988 EXTENT_DIRTY | EXTENT_DELALLOC, 0, 0, NULL,
989 GFP_NOFS);
990 goto out;
991 }
992 leaf = path->nodes[0];
993 if (ret > 0) {
994 struct btrfs_key found_key;
995 BUG_ON(!path->slots[0]);
996 path->slots[0]--;
997 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
998 if (found_key.objectid != BTRFS_FREE_SPACE_OBJECTID ||
999 found_key.offset != offset) {
1000 clear_extent_bit(&BTRFS_I(inode)->io_tree, 0,
1001 inode->i_size - 1,
1002 EXTENT_DIRTY | EXTENT_DELALLOC, 0, 0,
1003 NULL, GFP_NOFS);
1004 btrfs_release_path(path);
1005 goto out;
1006 }
1007 }
1008
1009 BTRFS_I(inode)->generation = trans->transid;
1010 header = btrfs_item_ptr(leaf, path->slots[0],
1011 struct btrfs_free_space_header);
1012 btrfs_set_free_space_entries(leaf, header, entries);
1013 btrfs_set_free_space_bitmaps(leaf, header, bitmaps);
1014 btrfs_set_free_space_generation(leaf, header, trans->transid);
1015 btrfs_mark_buffer_dirty(leaf);
1016 btrfs_release_path(path);
1017
1018 err = 0;
1019 out:
1020 io_ctl_free(&io_ctl);
1021 if (err) {
1022 invalidate_inode_pages2(inode->i_mapping);
1023 BTRFS_I(inode)->generation = 0;
1024 }
1025 btrfs_update_inode(trans, root, inode);
1026 return err;
1027
1028 out_nospc:
1029 list_for_each_safe(pos, n, &bitmap_list) {
1030 struct btrfs_free_space *entry =
1031 list_entry(pos, struct btrfs_free_space, list);
1032 list_del_init(&entry->list);
1033 }
1034 io_ctl_drop_pages(&io_ctl);
1035 unlock_extent_cached(&BTRFS_I(inode)->io_tree, 0,
1036 i_size_read(inode) - 1, &cached_state, GFP_NOFS);
1037 goto out;
1038 }
1039
1040 int btrfs_write_out_cache(struct btrfs_root *root,
1041 struct btrfs_trans_handle *trans,
1042 struct btrfs_block_group_cache *block_group,
1043 struct btrfs_path *path)
1044 {
1045 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
1046 struct inode *inode;
1047 int ret = 0;
1048
1049 root = root->fs_info->tree_root;
1050
1051 spin_lock(&block_group->lock);
1052 if (block_group->disk_cache_state < BTRFS_DC_SETUP) {
1053 spin_unlock(&block_group->lock);
1054 return 0;
1055 }
1056 spin_unlock(&block_group->lock);
1057
1058 inode = lookup_free_space_inode(root, block_group, path);
1059 if (IS_ERR(inode))
1060 return 0;
1061
1062 ret = __btrfs_write_out_cache(root, inode, ctl, block_group, trans,
1063 path, block_group->key.objectid);
1064 if (ret) {
1065 spin_lock(&block_group->lock);
1066 block_group->disk_cache_state = BTRFS_DC_ERROR;
1067 spin_unlock(&block_group->lock);
1068 ret = 0;
1069 #ifdef DEBUG
1070 printk(KERN_ERR "btrfs: failed to write free space cace "
1071 "for block group %llu\n", block_group->key.objectid);
1072 #endif
1073 }
1074
1075 iput(inode);
1076 return ret;
1077 }
1078
1079 static inline unsigned long offset_to_bit(u64 bitmap_start, u32 unit,
1080 u64 offset)
1081 {
1082 BUG_ON(offset < bitmap_start);
1083 offset -= bitmap_start;
1084 return (unsigned long)(div_u64(offset, unit));
1085 }
1086
1087 static inline unsigned long bytes_to_bits(u64 bytes, u32 unit)
1088 {
1089 return (unsigned long)(div_u64(bytes, unit));
1090 }
1091
1092 static inline u64 offset_to_bitmap(struct btrfs_free_space_ctl *ctl,
1093 u64 offset)
1094 {
1095 u64 bitmap_start;
1096 u64 bytes_per_bitmap;
1097
1098 bytes_per_bitmap = BITS_PER_BITMAP * ctl->unit;
1099 bitmap_start = offset - ctl->start;
1100 bitmap_start = div64_u64(bitmap_start, bytes_per_bitmap);
1101 bitmap_start *= bytes_per_bitmap;
1102 bitmap_start += ctl->start;
1103
1104 return bitmap_start;
1105 }
1106
1107 static int tree_insert_offset(struct rb_root *root, u64 offset,
1108 struct rb_node *node, int bitmap)
1109 {
1110 struct rb_node **p = &root->rb_node;
1111 struct rb_node *parent = NULL;
1112 struct btrfs_free_space *info;
1113
1114 while (*p) {
1115 parent = *p;
1116 info = rb_entry(parent, struct btrfs_free_space, offset_index);
1117
1118 if (offset < info->offset) {
1119 p = &(*p)->rb_left;
1120 } else if (offset > info->offset) {
1121 p = &(*p)->rb_right;
1122 } else {
1123 /*
1124 * we could have a bitmap entry and an extent entry
1125 * share the same offset. If this is the case, we want
1126 * the extent entry to always be found first if we do a
1127 * linear search through the tree, since we want to have
1128 * the quickest allocation time, and allocating from an
1129 * extent is faster than allocating from a bitmap. So
1130 * if we're inserting a bitmap and we find an entry at
1131 * this offset, we want to go right, or after this entry
1132 * logically. If we are inserting an extent and we've
1133 * found a bitmap, we want to go left, or before
1134 * logically.
1135 */
1136 if (bitmap) {
1137 if (info->bitmap) {
1138 WARN_ON_ONCE(1);
1139 return -EEXIST;
1140 }
1141 p = &(*p)->rb_right;
1142 } else {
1143 if (!info->bitmap) {
1144 WARN_ON_ONCE(1);
1145 return -EEXIST;
1146 }
1147 p = &(*p)->rb_left;
1148 }
1149 }
1150 }
1151
1152 rb_link_node(node, parent, p);
1153 rb_insert_color(node, root);
1154
1155 return 0;
1156 }
1157
1158 /*
1159 * searches the tree for the given offset.
1160 *
1161 * fuzzy - If this is set, then we are trying to make an allocation, and we just
1162 * want a section that has at least bytes size and comes at or after the given
1163 * offset.
1164 */
1165 static struct btrfs_free_space *
1166 tree_search_offset(struct btrfs_free_space_ctl *ctl,
1167 u64 offset, int bitmap_only, int fuzzy)
1168 {
1169 struct rb_node *n = ctl->free_space_offset.rb_node;
1170 struct btrfs_free_space *entry, *prev = NULL;
1171
1172 /* find entry that is closest to the 'offset' */
1173 while (1) {
1174 if (!n) {
1175 entry = NULL;
1176 break;
1177 }
1178
1179 entry = rb_entry(n, struct btrfs_free_space, offset_index);
1180 prev = entry;
1181
1182 if (offset < entry->offset)
1183 n = n->rb_left;
1184 else if (offset > entry->offset)
1185 n = n->rb_right;
1186 else
1187 break;
1188 }
1189
1190 if (bitmap_only) {
1191 if (!entry)
1192 return NULL;
1193 if (entry->bitmap)
1194 return entry;
1195
1196 /*
1197 * bitmap entry and extent entry may share same offset,
1198 * in that case, bitmap entry comes after extent entry.
1199 */
1200 n = rb_next(n);
1201 if (!n)
1202 return NULL;
1203 entry = rb_entry(n, struct btrfs_free_space, offset_index);
1204 if (entry->offset != offset)
1205 return NULL;
1206
1207 WARN_ON(!entry->bitmap);
1208 return entry;
1209 } else if (entry) {
1210 if (entry->bitmap) {
1211 /*
1212 * if previous extent entry covers the offset,
1213 * we should return it instead of the bitmap entry
1214 */
1215 n = &entry->offset_index;
1216 while (1) {
1217 n = rb_prev(n);
1218 if (!n)
1219 break;
1220 prev = rb_entry(n, struct btrfs_free_space,
1221 offset_index);
1222 if (!prev->bitmap) {
1223 if (prev->offset + prev->bytes > offset)
1224 entry = prev;
1225 break;
1226 }
1227 }
1228 }
1229 return entry;
1230 }
1231
1232 if (!prev)
1233 return NULL;
1234
1235 /* find last entry before the 'offset' */
1236 entry = prev;
1237 if (entry->offset > offset) {
1238 n = rb_prev(&entry->offset_index);
1239 if (n) {
1240 entry = rb_entry(n, struct btrfs_free_space,
1241 offset_index);
1242 BUG_ON(entry->offset > offset);
1243 } else {
1244 if (fuzzy)
1245 return entry;
1246 else
1247 return NULL;
1248 }
1249 }
1250
1251 if (entry->bitmap) {
1252 n = &entry->offset_index;
1253 while (1) {
1254 n = rb_prev(n);
1255 if (!n)
1256 break;
1257 prev = rb_entry(n, struct btrfs_free_space,
1258 offset_index);
1259 if (!prev->bitmap) {
1260 if (prev->offset + prev->bytes > offset)
1261 return prev;
1262 break;
1263 }
1264 }
1265 if (entry->offset + BITS_PER_BITMAP * ctl->unit > offset)
1266 return entry;
1267 } else if (entry->offset + entry->bytes > offset)
1268 return entry;
1269
1270 if (!fuzzy)
1271 return NULL;
1272
1273 while (1) {
1274 if (entry->bitmap) {
1275 if (entry->offset + BITS_PER_BITMAP *
1276 ctl->unit > offset)
1277 break;
1278 } else {
1279 if (entry->offset + entry->bytes > offset)
1280 break;
1281 }
1282
1283 n = rb_next(&entry->offset_index);
1284 if (!n)
1285 return NULL;
1286 entry = rb_entry(n, struct btrfs_free_space, offset_index);
1287 }
1288 return entry;
1289 }
1290
1291 static inline void
1292 __unlink_free_space(struct btrfs_free_space_ctl *ctl,
1293 struct btrfs_free_space *info)
1294 {
1295 rb_erase(&info->offset_index, &ctl->free_space_offset);
1296 ctl->free_extents--;
1297 }
1298
1299 static void unlink_free_space(struct btrfs_free_space_ctl *ctl,
1300 struct btrfs_free_space *info)
1301 {
1302 __unlink_free_space(ctl, info);
1303 ctl->free_space -= info->bytes;
1304 }
1305
1306 static int link_free_space(struct btrfs_free_space_ctl *ctl,
1307 struct btrfs_free_space *info)
1308 {
1309 int ret = 0;
1310
1311 BUG_ON(!info->bitmap && !info->bytes);
1312 ret = tree_insert_offset(&ctl->free_space_offset, info->offset,
1313 &info->offset_index, (info->bitmap != NULL));
1314 if (ret)
1315 return ret;
1316
1317 ctl->free_space += info->bytes;
1318 ctl->free_extents++;
1319 return ret;
1320 }
1321
1322 static void recalculate_thresholds(struct btrfs_free_space_ctl *ctl)
1323 {
1324 struct btrfs_block_group_cache *block_group = ctl->private;
1325 u64 max_bytes;
1326 u64 bitmap_bytes;
1327 u64 extent_bytes;
1328 u64 size = block_group->key.offset;
1329 u64 bytes_per_bg = BITS_PER_BITMAP * block_group->sectorsize;
1330 int max_bitmaps = div64_u64(size + bytes_per_bg - 1, bytes_per_bg);
1331
1332 BUG_ON(ctl->total_bitmaps > max_bitmaps);
1333
1334 /*
1335 * The goal is to keep the total amount of memory used per 1gb of space
1336 * at or below 32k, so we need to adjust how much memory we allow to be
1337 * used by extent based free space tracking
1338 */
1339 if (size < 1024 * 1024 * 1024)
1340 max_bytes = MAX_CACHE_BYTES_PER_GIG;
1341 else
1342 max_bytes = MAX_CACHE_BYTES_PER_GIG *
1343 div64_u64(size, 1024 * 1024 * 1024);
1344
1345 /*
1346 * we want to account for 1 more bitmap than what we have so we can make
1347 * sure we don't go over our overall goal of MAX_CACHE_BYTES_PER_GIG as
1348 * we add more bitmaps.
1349 */
1350 bitmap_bytes = (ctl->total_bitmaps + 1) * PAGE_CACHE_SIZE;
1351
1352 if (bitmap_bytes >= max_bytes) {
1353 ctl->extents_thresh = 0;
1354 return;
1355 }
1356
1357 /*
1358 * we want the extent entry threshold to always be at most 1/2 the maxw
1359 * bytes we can have, or whatever is less than that.
1360 */
1361 extent_bytes = max_bytes - bitmap_bytes;
1362 extent_bytes = min_t(u64, extent_bytes, div64_u64(max_bytes, 2));
1363
1364 ctl->extents_thresh =
1365 div64_u64(extent_bytes, (sizeof(struct btrfs_free_space)));
1366 }
1367
1368 static inline void __bitmap_clear_bits(struct btrfs_free_space_ctl *ctl,
1369 struct btrfs_free_space *info,
1370 u64 offset, u64 bytes)
1371 {
1372 unsigned long start, count;
1373
1374 start = offset_to_bit(info->offset, ctl->unit, offset);
1375 count = bytes_to_bits(bytes, ctl->unit);
1376 BUG_ON(start + count > BITS_PER_BITMAP);
1377
1378 bitmap_clear(info->bitmap, start, count);
1379
1380 info->bytes -= bytes;
1381 }
1382
1383 static void bitmap_clear_bits(struct btrfs_free_space_ctl *ctl,
1384 struct btrfs_free_space *info, u64 offset,
1385 u64 bytes)
1386 {
1387 __bitmap_clear_bits(ctl, info, offset, bytes);
1388 ctl->free_space -= bytes;
1389 }
1390
1391 static void bitmap_set_bits(struct btrfs_free_space_ctl *ctl,
1392 struct btrfs_free_space *info, u64 offset,
1393 u64 bytes)
1394 {
1395 unsigned long start, count;
1396
1397 start = offset_to_bit(info->offset, ctl->unit, offset);
1398 count = bytes_to_bits(bytes, ctl->unit);
1399 BUG_ON(start + count > BITS_PER_BITMAP);
1400
1401 bitmap_set(info->bitmap, start, count);
1402
1403 info->bytes += bytes;
1404 ctl->free_space += bytes;
1405 }
1406
1407 static int search_bitmap(struct btrfs_free_space_ctl *ctl,
1408 struct btrfs_free_space *bitmap_info, u64 *offset,
1409 u64 *bytes)
1410 {
1411 unsigned long found_bits = 0;
1412 unsigned long bits, i;
1413 unsigned long next_zero;
1414
1415 i = offset_to_bit(bitmap_info->offset, ctl->unit,
1416 max_t(u64, *offset, bitmap_info->offset));
1417 bits = bytes_to_bits(*bytes, ctl->unit);
1418
1419 for (i = find_next_bit(bitmap_info->bitmap, BITS_PER_BITMAP, i);
1420 i < BITS_PER_BITMAP;
1421 i = find_next_bit(bitmap_info->bitmap, BITS_PER_BITMAP, i + 1)) {
1422 next_zero = find_next_zero_bit(bitmap_info->bitmap,
1423 BITS_PER_BITMAP, i);
1424 if ((next_zero - i) >= bits) {
1425 found_bits = next_zero - i;
1426 break;
1427 }
1428 i = next_zero;
1429 }
1430
1431 if (found_bits) {
1432 *offset = (u64)(i * ctl->unit) + bitmap_info->offset;
1433 *bytes = (u64)(found_bits) * ctl->unit;
1434 return 0;
1435 }
1436
1437 return -1;
1438 }
1439
1440 static struct btrfs_free_space *
1441 find_free_space(struct btrfs_free_space_ctl *ctl, u64 *offset, u64 *bytes)
1442 {
1443 struct btrfs_free_space *entry;
1444 struct rb_node *node;
1445 int ret;
1446
1447 if (!ctl->free_space_offset.rb_node)
1448 return NULL;
1449
1450 entry = tree_search_offset(ctl, offset_to_bitmap(ctl, *offset), 0, 1);
1451 if (!entry)
1452 return NULL;
1453
1454 for (node = &entry->offset_index; node; node = rb_next(node)) {
1455 entry = rb_entry(node, struct btrfs_free_space, offset_index);
1456 if (entry->bytes < *bytes)
1457 continue;
1458
1459 if (entry->bitmap) {
1460 ret = search_bitmap(ctl, entry, offset, bytes);
1461 if (!ret)
1462 return entry;
1463 continue;
1464 }
1465
1466 *offset = entry->offset;
1467 *bytes = entry->bytes;
1468 return entry;
1469 }
1470
1471 return NULL;
1472 }
1473
1474 static void add_new_bitmap(struct btrfs_free_space_ctl *ctl,
1475 struct btrfs_free_space *info, u64 offset)
1476 {
1477 info->offset = offset_to_bitmap(ctl, offset);
1478 info->bytes = 0;
1479 INIT_LIST_HEAD(&info->list);
1480 link_free_space(ctl, info);
1481 ctl->total_bitmaps++;
1482
1483 ctl->op->recalc_thresholds(ctl);
1484 }
1485
1486 static void free_bitmap(struct btrfs_free_space_ctl *ctl,
1487 struct btrfs_free_space *bitmap_info)
1488 {
1489 unlink_free_space(ctl, bitmap_info);
1490 kfree(bitmap_info->bitmap);
1491 kmem_cache_free(btrfs_free_space_cachep, bitmap_info);
1492 ctl->total_bitmaps--;
1493 ctl->op->recalc_thresholds(ctl);
1494 }
1495
1496 static noinline int remove_from_bitmap(struct btrfs_free_space_ctl *ctl,
1497 struct btrfs_free_space *bitmap_info,
1498 u64 *offset, u64 *bytes)
1499 {
1500 u64 end;
1501 u64 search_start, search_bytes;
1502 int ret;
1503
1504 again:
1505 end = bitmap_info->offset + (u64)(BITS_PER_BITMAP * ctl->unit) - 1;
1506
1507 /*
1508 * XXX - this can go away after a few releases.
1509 *
1510 * since the only user of btrfs_remove_free_space is the tree logging
1511 * stuff, and the only way to test that is under crash conditions, we
1512 * want to have this debug stuff here just in case somethings not
1513 * working. Search the bitmap for the space we are trying to use to
1514 * make sure its actually there. If its not there then we need to stop
1515 * because something has gone wrong.
1516 */
1517 search_start = *offset;
1518 search_bytes = *bytes;
1519 search_bytes = min(search_bytes, end - search_start + 1);
1520 ret = search_bitmap(ctl, bitmap_info, &search_start, &search_bytes);
1521 BUG_ON(ret < 0 || search_start != *offset);
1522
1523 if (*offset > bitmap_info->offset && *offset + *bytes > end) {
1524 bitmap_clear_bits(ctl, bitmap_info, *offset, end - *offset + 1);
1525 *bytes -= end - *offset + 1;
1526 *offset = end + 1;
1527 } else if (*offset >= bitmap_info->offset && *offset + *bytes <= end) {
1528 bitmap_clear_bits(ctl, bitmap_info, *offset, *bytes);
1529 *bytes = 0;
1530 }
1531
1532 if (*bytes) {
1533 struct rb_node *next = rb_next(&bitmap_info->offset_index);
1534 if (!bitmap_info->bytes)
1535 free_bitmap(ctl, bitmap_info);
1536
1537 /*
1538 * no entry after this bitmap, but we still have bytes to
1539 * remove, so something has gone wrong.
1540 */
1541 if (!next)
1542 return -EINVAL;
1543
1544 bitmap_info = rb_entry(next, struct btrfs_free_space,
1545 offset_index);
1546
1547 /*
1548 * if the next entry isn't a bitmap we need to return to let the
1549 * extent stuff do its work.
1550 */
1551 if (!bitmap_info->bitmap)
1552 return -EAGAIN;
1553
1554 /*
1555 * Ok the next item is a bitmap, but it may not actually hold
1556 * the information for the rest of this free space stuff, so
1557 * look for it, and if we don't find it return so we can try
1558 * everything over again.
1559 */
1560 search_start = *offset;
1561 search_bytes = *bytes;
1562 ret = search_bitmap(ctl, bitmap_info, &search_start,
1563 &search_bytes);
1564 if (ret < 0 || search_start != *offset)
1565 return -EAGAIN;
1566
1567 goto again;
1568 } else if (!bitmap_info->bytes)
1569 free_bitmap(ctl, bitmap_info);
1570
1571 return 0;
1572 }
1573
1574 static u64 add_bytes_to_bitmap(struct btrfs_free_space_ctl *ctl,
1575 struct btrfs_free_space *info, u64 offset,
1576 u64 bytes)
1577 {
1578 u64 bytes_to_set = 0;
1579 u64 end;
1580
1581 end = info->offset + (u64)(BITS_PER_BITMAP * ctl->unit);
1582
1583 bytes_to_set = min(end - offset, bytes);
1584
1585 bitmap_set_bits(ctl, info, offset, bytes_to_set);
1586
1587 return bytes_to_set;
1588
1589 }
1590
1591 static bool use_bitmap(struct btrfs_free_space_ctl *ctl,
1592 struct btrfs_free_space *info)
1593 {
1594 struct btrfs_block_group_cache *block_group = ctl->private;
1595
1596 /*
1597 * If we are below the extents threshold then we can add this as an
1598 * extent, and don't have to deal with the bitmap
1599 */
1600 if (ctl->free_extents < ctl->extents_thresh) {
1601 /*
1602 * If this block group has some small extents we don't want to
1603 * use up all of our free slots in the cache with them, we want
1604 * to reserve them to larger extents, however if we have plent
1605 * of cache left then go ahead an dadd them, no sense in adding
1606 * the overhead of a bitmap if we don't have to.
1607 */
1608 if (info->bytes <= block_group->sectorsize * 4) {
1609 if (ctl->free_extents * 2 <= ctl->extents_thresh)
1610 return false;
1611 } else {
1612 return false;
1613 }
1614 }
1615
1616 /*
1617 * some block groups are so tiny they can't be enveloped by a bitmap, so
1618 * don't even bother to create a bitmap for this
1619 */
1620 if (BITS_PER_BITMAP * block_group->sectorsize >
1621 block_group->key.offset)
1622 return false;
1623
1624 return true;
1625 }
1626
1627 static struct btrfs_free_space_op free_space_op = {
1628 .recalc_thresholds = recalculate_thresholds,
1629 .use_bitmap = use_bitmap,
1630 };
1631
1632 static int insert_into_bitmap(struct btrfs_free_space_ctl *ctl,
1633 struct btrfs_free_space *info)
1634 {
1635 struct btrfs_free_space *bitmap_info;
1636 struct btrfs_block_group_cache *block_group = NULL;
1637 int added = 0;
1638 u64 bytes, offset, bytes_added;
1639 int ret;
1640
1641 bytes = info->bytes;
1642 offset = info->offset;
1643
1644 if (!ctl->op->use_bitmap(ctl, info))
1645 return 0;
1646
1647 if (ctl->op == &free_space_op)
1648 block_group = ctl->private;
1649 again:
1650 /*
1651 * Since we link bitmaps right into the cluster we need to see if we
1652 * have a cluster here, and if so and it has our bitmap we need to add
1653 * the free space to that bitmap.
1654 */
1655 if (block_group && !list_empty(&block_group->cluster_list)) {
1656 struct btrfs_free_cluster *cluster;
1657 struct rb_node *node;
1658 struct btrfs_free_space *entry;
1659
1660 cluster = list_entry(block_group->cluster_list.next,
1661 struct btrfs_free_cluster,
1662 block_group_list);
1663 spin_lock(&cluster->lock);
1664 node = rb_first(&cluster->root);
1665 if (!node) {
1666 spin_unlock(&cluster->lock);
1667 goto no_cluster_bitmap;
1668 }
1669
1670 entry = rb_entry(node, struct btrfs_free_space, offset_index);
1671 if (!entry->bitmap) {
1672 spin_unlock(&cluster->lock);
1673 goto no_cluster_bitmap;
1674 }
1675
1676 if (entry->offset == offset_to_bitmap(ctl, offset)) {
1677 bytes_added = add_bytes_to_bitmap(ctl, entry,
1678 offset, bytes);
1679 bytes -= bytes_added;
1680 offset += bytes_added;
1681 }
1682 spin_unlock(&cluster->lock);
1683 if (!bytes) {
1684 ret = 1;
1685 goto out;
1686 }
1687 }
1688
1689 no_cluster_bitmap:
1690 bitmap_info = tree_search_offset(ctl, offset_to_bitmap(ctl, offset),
1691 1, 0);
1692 if (!bitmap_info) {
1693 BUG_ON(added);
1694 goto new_bitmap;
1695 }
1696
1697 bytes_added = add_bytes_to_bitmap(ctl, bitmap_info, offset, bytes);
1698 bytes -= bytes_added;
1699 offset += bytes_added;
1700 added = 0;
1701
1702 if (!bytes) {
1703 ret = 1;
1704 goto out;
1705 } else
1706 goto again;
1707
1708 new_bitmap:
1709 if (info && info->bitmap) {
1710 add_new_bitmap(ctl, info, offset);
1711 added = 1;
1712 info = NULL;
1713 goto again;
1714 } else {
1715 spin_unlock(&ctl->tree_lock);
1716
1717 /* no pre-allocated info, allocate a new one */
1718 if (!info) {
1719 info = kmem_cache_zalloc(btrfs_free_space_cachep,
1720 GFP_NOFS);
1721 if (!info) {
1722 spin_lock(&ctl->tree_lock);
1723 ret = -ENOMEM;
1724 goto out;
1725 }
1726 }
1727
1728 /* allocate the bitmap */
1729 info->bitmap = kzalloc(PAGE_CACHE_SIZE, GFP_NOFS);
1730 spin_lock(&ctl->tree_lock);
1731 if (!info->bitmap) {
1732 ret = -ENOMEM;
1733 goto out;
1734 }
1735 goto again;
1736 }
1737
1738 out:
1739 if (info) {
1740 if (info->bitmap)
1741 kfree(info->bitmap);
1742 kmem_cache_free(btrfs_free_space_cachep, info);
1743 }
1744
1745 return ret;
1746 }
1747
1748 static bool try_merge_free_space(struct btrfs_free_space_ctl *ctl,
1749 struct btrfs_free_space *info, bool update_stat)
1750 {
1751 struct btrfs_free_space *left_info;
1752 struct btrfs_free_space *right_info;
1753 bool merged = false;
1754 u64 offset = info->offset;
1755 u64 bytes = info->bytes;
1756
1757 /*
1758 * first we want to see if there is free space adjacent to the range we
1759 * are adding, if there is remove that struct and add a new one to
1760 * cover the entire range
1761 */
1762 right_info = tree_search_offset(ctl, offset + bytes, 0, 0);
1763 if (right_info && rb_prev(&right_info->offset_index))
1764 left_info = rb_entry(rb_prev(&right_info->offset_index),
1765 struct btrfs_free_space, offset_index);
1766 else
1767 left_info = tree_search_offset(ctl, offset - 1, 0, 0);
1768
1769 if (right_info && !right_info->bitmap) {
1770 if (update_stat)
1771 unlink_free_space(ctl, right_info);
1772 else
1773 __unlink_free_space(ctl, right_info);
1774 info->bytes += right_info->bytes;
1775 kmem_cache_free(btrfs_free_space_cachep, right_info);
1776 merged = true;
1777 }
1778
1779 if (left_info && !left_info->bitmap &&
1780 left_info->offset + left_info->bytes == offset) {
1781 if (update_stat)
1782 unlink_free_space(ctl, left_info);
1783 else
1784 __unlink_free_space(ctl, left_info);
1785 info->offset = left_info->offset;
1786 info->bytes += left_info->bytes;
1787 kmem_cache_free(btrfs_free_space_cachep, left_info);
1788 merged = true;
1789 }
1790
1791 return merged;
1792 }
1793
1794 int __btrfs_add_free_space(struct btrfs_free_space_ctl *ctl,
1795 u64 offset, u64 bytes)
1796 {
1797 struct btrfs_free_space *info;
1798 int ret = 0;
1799
1800 info = kmem_cache_zalloc(btrfs_free_space_cachep, GFP_NOFS);
1801 if (!info)
1802 return -ENOMEM;
1803
1804 info->offset = offset;
1805 info->bytes = bytes;
1806
1807 spin_lock(&ctl->tree_lock);
1808
1809 if (try_merge_free_space(ctl, info, true))
1810 goto link;
1811
1812 /*
1813 * There was no extent directly to the left or right of this new
1814 * extent then we know we're going to have to allocate a new extent, so
1815 * before we do that see if we need to drop this into a bitmap
1816 */
1817 ret = insert_into_bitmap(ctl, info);
1818 if (ret < 0) {
1819 goto out;
1820 } else if (ret) {
1821 ret = 0;
1822 goto out;
1823 }
1824 link:
1825 ret = link_free_space(ctl, info);
1826 if (ret)
1827 kmem_cache_free(btrfs_free_space_cachep, info);
1828 out:
1829 spin_unlock(&ctl->tree_lock);
1830
1831 if (ret) {
1832 printk(KERN_CRIT "btrfs: unable to add free space :%d\n", ret);
1833 BUG_ON(ret == -EEXIST);
1834 }
1835
1836 return ret;
1837 }
1838
1839 int btrfs_remove_free_space(struct btrfs_block_group_cache *block_group,
1840 u64 offset, u64 bytes)
1841 {
1842 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
1843 struct btrfs_free_space *info;
1844 struct btrfs_free_space *next_info = NULL;
1845 int ret = 0;
1846
1847 spin_lock(&ctl->tree_lock);
1848
1849 again:
1850 info = tree_search_offset(ctl, offset, 0, 0);
1851 if (!info) {
1852 /*
1853 * oops didn't find an extent that matched the space we wanted
1854 * to remove, look for a bitmap instead
1855 */
1856 info = tree_search_offset(ctl, offset_to_bitmap(ctl, offset),
1857 1, 0);
1858 if (!info) {
1859 /* the tree logging code might be calling us before we
1860 * have fully loaded the free space rbtree for this
1861 * block group. So it is possible the entry won't
1862 * be in the rbtree yet at all. The caching code
1863 * will make sure not to put it in the rbtree if
1864 * the logging code has pinned it.
1865 */
1866 goto out_lock;
1867 }
1868 }
1869
1870 if (info->bytes < bytes && rb_next(&info->offset_index)) {
1871 u64 end;
1872 next_info = rb_entry(rb_next(&info->offset_index),
1873 struct btrfs_free_space,
1874 offset_index);
1875
1876 if (next_info->bitmap)
1877 end = next_info->offset +
1878 BITS_PER_BITMAP * ctl->unit - 1;
1879 else
1880 end = next_info->offset + next_info->bytes;
1881
1882 if (next_info->bytes < bytes ||
1883 next_info->offset > offset || offset > end) {
1884 printk(KERN_CRIT "Found free space at %llu, size %llu,"
1885 " trying to use %llu\n",
1886 (unsigned long long)info->offset,
1887 (unsigned long long)info->bytes,
1888 (unsigned long long)bytes);
1889 WARN_ON(1);
1890 ret = -EINVAL;
1891 goto out_lock;
1892 }
1893
1894 info = next_info;
1895 }
1896
1897 if (info->bytes == bytes) {
1898 unlink_free_space(ctl, info);
1899 if (info->bitmap) {
1900 kfree(info->bitmap);
1901 ctl->total_bitmaps--;
1902 }
1903 kmem_cache_free(btrfs_free_space_cachep, info);
1904 ret = 0;
1905 goto out_lock;
1906 }
1907
1908 if (!info->bitmap && info->offset == offset) {
1909 unlink_free_space(ctl, info);
1910 info->offset += bytes;
1911 info->bytes -= bytes;
1912 ret = link_free_space(ctl, info);
1913 WARN_ON(ret);
1914 goto out_lock;
1915 }
1916
1917 if (!info->bitmap && info->offset <= offset &&
1918 info->offset + info->bytes >= offset + bytes) {
1919 u64 old_start = info->offset;
1920 /*
1921 * we're freeing space in the middle of the info,
1922 * this can happen during tree log replay
1923 *
1924 * first unlink the old info and then
1925 * insert it again after the hole we're creating
1926 */
1927 unlink_free_space(ctl, info);
1928 if (offset + bytes < info->offset + info->bytes) {
1929 u64 old_end = info->offset + info->bytes;
1930
1931 info->offset = offset + bytes;
1932 info->bytes = old_end - info->offset;
1933 ret = link_free_space(ctl, info);
1934 WARN_ON(ret);
1935 if (ret)
1936 goto out_lock;
1937 } else {
1938 /* the hole we're creating ends at the end
1939 * of the info struct, just free the info
1940 */
1941 kmem_cache_free(btrfs_free_space_cachep, info);
1942 }
1943 spin_unlock(&ctl->tree_lock);
1944
1945 /* step two, insert a new info struct to cover
1946 * anything before the hole
1947 */
1948 ret = btrfs_add_free_space(block_group, old_start,
1949 offset - old_start);
1950 WARN_ON(ret);
1951 goto out;
1952 }
1953
1954 ret = remove_from_bitmap(ctl, info, &offset, &bytes);
1955 if (ret == -EAGAIN)
1956 goto again;
1957 BUG_ON(ret);
1958 out_lock:
1959 spin_unlock(&ctl->tree_lock);
1960 out:
1961 return ret;
1962 }
1963
1964 void btrfs_dump_free_space(struct btrfs_block_group_cache *block_group,
1965 u64 bytes)
1966 {
1967 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
1968 struct btrfs_free_space *info;
1969 struct rb_node *n;
1970 int count = 0;
1971
1972 for (n = rb_first(&ctl->free_space_offset); n; n = rb_next(n)) {
1973 info = rb_entry(n, struct btrfs_free_space, offset_index);
1974 if (info->bytes >= bytes)
1975 count++;
1976 printk(KERN_CRIT "entry offset %llu, bytes %llu, bitmap %s\n",
1977 (unsigned long long)info->offset,
1978 (unsigned long long)info->bytes,
1979 (info->bitmap) ? "yes" : "no");
1980 }
1981 printk(KERN_INFO "block group has cluster?: %s\n",
1982 list_empty(&block_group->cluster_list) ? "no" : "yes");
1983 printk(KERN_INFO "%d blocks of free space at or bigger than bytes is"
1984 "\n", count);
1985 }
1986
1987 void btrfs_init_free_space_ctl(struct btrfs_block_group_cache *block_group)
1988 {
1989 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
1990
1991 spin_lock_init(&ctl->tree_lock);
1992 ctl->unit = block_group->sectorsize;
1993 ctl->start = block_group->key.objectid;
1994 ctl->private = block_group;
1995 ctl->op = &free_space_op;
1996
1997 /*
1998 * we only want to have 32k of ram per block group for keeping
1999 * track of free space, and if we pass 1/2 of that we want to
2000 * start converting things over to using bitmaps
2001 */
2002 ctl->extents_thresh = ((1024 * 32) / 2) /
2003 sizeof(struct btrfs_free_space);
2004 }
2005
2006 /*
2007 * for a given cluster, put all of its extents back into the free
2008 * space cache. If the block group passed doesn't match the block group
2009 * pointed to by the cluster, someone else raced in and freed the
2010 * cluster already. In that case, we just return without changing anything
2011 */
2012 static int
2013 __btrfs_return_cluster_to_free_space(
2014 struct btrfs_block_group_cache *block_group,
2015 struct btrfs_free_cluster *cluster)
2016 {
2017 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2018 struct btrfs_free_space *entry;
2019 struct rb_node *node;
2020
2021 spin_lock(&cluster->lock);
2022 if (cluster->block_group != block_group)
2023 goto out;
2024
2025 cluster->block_group = NULL;
2026 cluster->window_start = 0;
2027 list_del_init(&cluster->block_group_list);
2028
2029 node = rb_first(&cluster->root);
2030 while (node) {
2031 bool bitmap;
2032
2033 entry = rb_entry(node, struct btrfs_free_space, offset_index);
2034 node = rb_next(&entry->offset_index);
2035 rb_erase(&entry->offset_index, &cluster->root);
2036
2037 bitmap = (entry->bitmap != NULL);
2038 if (!bitmap)
2039 try_merge_free_space(ctl, entry, false);
2040 tree_insert_offset(&ctl->free_space_offset,
2041 entry->offset, &entry->offset_index, bitmap);
2042 }
2043 cluster->root = RB_ROOT;
2044
2045 out:
2046 spin_unlock(&cluster->lock);
2047 btrfs_put_block_group(block_group);
2048 return 0;
2049 }
2050
2051 void __btrfs_remove_free_space_cache_locked(struct btrfs_free_space_ctl *ctl)
2052 {
2053 struct btrfs_free_space *info;
2054 struct rb_node *node;
2055
2056 while ((node = rb_last(&ctl->free_space_offset)) != NULL) {
2057 info = rb_entry(node, struct btrfs_free_space, offset_index);
2058 if (!info->bitmap) {
2059 unlink_free_space(ctl, info);
2060 kmem_cache_free(btrfs_free_space_cachep, info);
2061 } else {
2062 free_bitmap(ctl, info);
2063 }
2064 if (need_resched()) {
2065 spin_unlock(&ctl->tree_lock);
2066 cond_resched();
2067 spin_lock(&ctl->tree_lock);
2068 }
2069 }
2070 }
2071
2072 void __btrfs_remove_free_space_cache(struct btrfs_free_space_ctl *ctl)
2073 {
2074 spin_lock(&ctl->tree_lock);
2075 __btrfs_remove_free_space_cache_locked(ctl);
2076 spin_unlock(&ctl->tree_lock);
2077 }
2078
2079 void btrfs_remove_free_space_cache(struct btrfs_block_group_cache *block_group)
2080 {
2081 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2082 struct btrfs_free_cluster *cluster;
2083 struct list_head *head;
2084
2085 spin_lock(&ctl->tree_lock);
2086 while ((head = block_group->cluster_list.next) !=
2087 &block_group->cluster_list) {
2088 cluster = list_entry(head, struct btrfs_free_cluster,
2089 block_group_list);
2090
2091 WARN_ON(cluster->block_group != block_group);
2092 __btrfs_return_cluster_to_free_space(block_group, cluster);
2093 if (need_resched()) {
2094 spin_unlock(&ctl->tree_lock);
2095 cond_resched();
2096 spin_lock(&ctl->tree_lock);
2097 }
2098 }
2099 __btrfs_remove_free_space_cache_locked(ctl);
2100 spin_unlock(&ctl->tree_lock);
2101
2102 }
2103
2104 u64 btrfs_find_space_for_alloc(struct btrfs_block_group_cache *block_group,
2105 u64 offset, u64 bytes, u64 empty_size)
2106 {
2107 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2108 struct btrfs_free_space *entry = NULL;
2109 u64 bytes_search = bytes + empty_size;
2110 u64 ret = 0;
2111
2112 spin_lock(&ctl->tree_lock);
2113 entry = find_free_space(ctl, &offset, &bytes_search);
2114 if (!entry)
2115 goto out;
2116
2117 ret = offset;
2118 if (entry->bitmap) {
2119 bitmap_clear_bits(ctl, entry, offset, bytes);
2120 if (!entry->bytes)
2121 free_bitmap(ctl, entry);
2122 } else {
2123 unlink_free_space(ctl, entry);
2124 entry->offset += bytes;
2125 entry->bytes -= bytes;
2126 if (!entry->bytes)
2127 kmem_cache_free(btrfs_free_space_cachep, entry);
2128 else
2129 link_free_space(ctl, entry);
2130 }
2131
2132 out:
2133 spin_unlock(&ctl->tree_lock);
2134
2135 return ret;
2136 }
2137
2138 /*
2139 * given a cluster, put all of its extents back into the free space
2140 * cache. If a block group is passed, this function will only free
2141 * a cluster that belongs to the passed block group.
2142 *
2143 * Otherwise, it'll get a reference on the block group pointed to by the
2144 * cluster and remove the cluster from it.
2145 */
2146 int btrfs_return_cluster_to_free_space(
2147 struct btrfs_block_group_cache *block_group,
2148 struct btrfs_free_cluster *cluster)
2149 {
2150 struct btrfs_free_space_ctl *ctl;
2151 int ret;
2152
2153 /* first, get a safe pointer to the block group */
2154 spin_lock(&cluster->lock);
2155 if (!block_group) {
2156 block_group = cluster->block_group;
2157 if (!block_group) {
2158 spin_unlock(&cluster->lock);
2159 return 0;
2160 }
2161 } else if (cluster->block_group != block_group) {
2162 /* someone else has already freed it don't redo their work */
2163 spin_unlock(&cluster->lock);
2164 return 0;
2165 }
2166 atomic_inc(&block_group->count);
2167 spin_unlock(&cluster->lock);
2168
2169 ctl = block_group->free_space_ctl;
2170
2171 /* now return any extents the cluster had on it */
2172 spin_lock(&ctl->tree_lock);
2173 ret = __btrfs_return_cluster_to_free_space(block_group, cluster);
2174 spin_unlock(&ctl->tree_lock);
2175
2176 /* finally drop our ref */
2177 btrfs_put_block_group(block_group);
2178 return ret;
2179 }
2180
2181 static u64 btrfs_alloc_from_bitmap(struct btrfs_block_group_cache *block_group,
2182 struct btrfs_free_cluster *cluster,
2183 struct btrfs_free_space *entry,
2184 u64 bytes, u64 min_start)
2185 {
2186 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2187 int err;
2188 u64 search_start = cluster->window_start;
2189 u64 search_bytes = bytes;
2190 u64 ret = 0;
2191
2192 search_start = min_start;
2193 search_bytes = bytes;
2194
2195 err = search_bitmap(ctl, entry, &search_start, &search_bytes);
2196 if (err)
2197 return 0;
2198
2199 ret = search_start;
2200 __bitmap_clear_bits(ctl, entry, ret, bytes);
2201
2202 return ret;
2203 }
2204
2205 /*
2206 * given a cluster, try to allocate 'bytes' from it, returns 0
2207 * if it couldn't find anything suitably large, or a logical disk offset
2208 * if things worked out
2209 */
2210 u64 btrfs_alloc_from_cluster(struct btrfs_block_group_cache *block_group,
2211 struct btrfs_free_cluster *cluster, u64 bytes,
2212 u64 min_start)
2213 {
2214 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2215 struct btrfs_free_space *entry = NULL;
2216 struct rb_node *node;
2217 u64 ret = 0;
2218
2219 spin_lock(&cluster->lock);
2220 if (bytes > cluster->max_size)
2221 goto out;
2222
2223 if (cluster->block_group != block_group)
2224 goto out;
2225
2226 node = rb_first(&cluster->root);
2227 if (!node)
2228 goto out;
2229
2230 entry = rb_entry(node, struct btrfs_free_space, offset_index);
2231 while(1) {
2232 if (entry->bytes < bytes ||
2233 (!entry->bitmap && entry->offset < min_start)) {
2234 node = rb_next(&entry->offset_index);
2235 if (!node)
2236 break;
2237 entry = rb_entry(node, struct btrfs_free_space,
2238 offset_index);
2239 continue;
2240 }
2241
2242 if (entry->bitmap) {
2243 ret = btrfs_alloc_from_bitmap(block_group,
2244 cluster, entry, bytes,
2245 min_start);
2246 if (ret == 0) {
2247 node = rb_next(&entry->offset_index);
2248 if (!node)
2249 break;
2250 entry = rb_entry(node, struct btrfs_free_space,
2251 offset_index);
2252 continue;
2253 }
2254 } else {
2255 ret = entry->offset;
2256
2257 entry->offset += bytes;
2258 entry->bytes -= bytes;
2259 }
2260
2261 if (entry->bytes == 0)
2262 rb_erase(&entry->offset_index, &cluster->root);
2263 break;
2264 }
2265 out:
2266 spin_unlock(&cluster->lock);
2267
2268 if (!ret)
2269 return 0;
2270
2271 spin_lock(&ctl->tree_lock);
2272
2273 ctl->free_space -= bytes;
2274 if (entry->bytes == 0) {
2275 ctl->free_extents--;
2276 if (entry->bitmap) {
2277 kfree(entry->bitmap);
2278 ctl->total_bitmaps--;
2279 ctl->op->recalc_thresholds(ctl);
2280 }
2281 kmem_cache_free(btrfs_free_space_cachep, entry);
2282 }
2283
2284 spin_unlock(&ctl->tree_lock);
2285
2286 return ret;
2287 }
2288
2289 static int btrfs_bitmap_cluster(struct btrfs_block_group_cache *block_group,
2290 struct btrfs_free_space *entry,
2291 struct btrfs_free_cluster *cluster,
2292 u64 offset, u64 bytes,
2293 u64 cont1_bytes, u64 min_bytes)
2294 {
2295 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2296 unsigned long next_zero;
2297 unsigned long i;
2298 unsigned long want_bits;
2299 unsigned long min_bits;
2300 unsigned long found_bits;
2301 unsigned long start = 0;
2302 unsigned long total_found = 0;
2303 int ret;
2304
2305 i = offset_to_bit(entry->offset, block_group->sectorsize,
2306 max_t(u64, offset, entry->offset));
2307 want_bits = bytes_to_bits(bytes, block_group->sectorsize);
2308 min_bits = bytes_to_bits(min_bytes, block_group->sectorsize);
2309
2310 again:
2311 found_bits = 0;
2312 for (i = find_next_bit(entry->bitmap, BITS_PER_BITMAP, i);
2313 i < BITS_PER_BITMAP;
2314 i = find_next_bit(entry->bitmap, BITS_PER_BITMAP, i + 1)) {
2315 next_zero = find_next_zero_bit(entry->bitmap,
2316 BITS_PER_BITMAP, i);
2317 if (next_zero - i >= min_bits) {
2318 found_bits = next_zero - i;
2319 break;
2320 }
2321 i = next_zero;
2322 }
2323
2324 if (!found_bits)
2325 return -ENOSPC;
2326
2327 if (!total_found) {
2328 start = i;
2329 cluster->max_size = 0;
2330 }
2331
2332 total_found += found_bits;
2333
2334 if (cluster->max_size < found_bits * block_group->sectorsize)
2335 cluster->max_size = found_bits * block_group->sectorsize;
2336
2337 if (total_found < want_bits || cluster->max_size < cont1_bytes) {
2338 i = next_zero + 1;
2339 goto again;
2340 }
2341
2342 cluster->window_start = start * block_group->sectorsize +
2343 entry->offset;
2344 rb_erase(&entry->offset_index, &ctl->free_space_offset);
2345 ret = tree_insert_offset(&cluster->root, entry->offset,
2346 &entry->offset_index, 1);
2347 BUG_ON(ret);
2348
2349 trace_btrfs_setup_cluster(block_group, cluster,
2350 total_found * block_group->sectorsize, 1);
2351 return 0;
2352 }
2353
2354 /*
2355 * This searches the block group for just extents to fill the cluster with.
2356 * Try to find a cluster with at least bytes total bytes, at least one
2357 * extent of cont1_bytes, and other clusters of at least min_bytes.
2358 */
2359 static noinline int
2360 setup_cluster_no_bitmap(struct btrfs_block_group_cache *block_group,
2361 struct btrfs_free_cluster *cluster,
2362 struct list_head *bitmaps, u64 offset, u64 bytes,
2363 u64 cont1_bytes, u64 min_bytes)
2364 {
2365 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2366 struct btrfs_free_space *first = NULL;
2367 struct btrfs_free_space *entry = NULL;
2368 struct btrfs_free_space *last;
2369 struct rb_node *node;
2370 u64 window_start;
2371 u64 window_free;
2372 u64 max_extent;
2373 u64 total_size = 0;
2374
2375 entry = tree_search_offset(ctl, offset, 0, 1);
2376 if (!entry)
2377 return -ENOSPC;
2378
2379 /*
2380 * We don't want bitmaps, so just move along until we find a normal
2381 * extent entry.
2382 */
2383 while (entry->bitmap || entry->bytes < min_bytes) {
2384 if (entry->bitmap && list_empty(&entry->list))
2385 list_add_tail(&entry->list, bitmaps);
2386 node = rb_next(&entry->offset_index);
2387 if (!node)
2388 return -ENOSPC;
2389 entry = rb_entry(node, struct btrfs_free_space, offset_index);
2390 }
2391
2392 window_start = entry->offset;
2393 window_free = entry->bytes;
2394 max_extent = entry->bytes;
2395 first = entry;
2396 last = entry;
2397
2398 for (node = rb_next(&entry->offset_index); node;
2399 node = rb_next(&entry->offset_index)) {
2400 entry = rb_entry(node, struct btrfs_free_space, offset_index);
2401
2402 if (entry->bitmap) {
2403 if (list_empty(&entry->list))
2404 list_add_tail(&entry->list, bitmaps);
2405 continue;
2406 }
2407
2408 if (entry->bytes < min_bytes)
2409 continue;
2410
2411 last = entry;
2412 window_free += entry->bytes;
2413 if (entry->bytes > max_extent)
2414 max_extent = entry->bytes;
2415 }
2416
2417 if (window_free < bytes || max_extent < cont1_bytes)
2418 return -ENOSPC;
2419
2420 cluster->window_start = first->offset;
2421
2422 node = &first->offset_index;
2423
2424 /*
2425 * now we've found our entries, pull them out of the free space
2426 * cache and put them into the cluster rbtree
2427 */
2428 do {
2429 int ret;
2430
2431 entry = rb_entry(node, struct btrfs_free_space, offset_index);
2432 node = rb_next(&entry->offset_index);
2433 if (entry->bitmap || entry->bytes < min_bytes)
2434 continue;
2435
2436 rb_erase(&entry->offset_index, &ctl->free_space_offset);
2437 ret = tree_insert_offset(&cluster->root, entry->offset,
2438 &entry->offset_index, 0);
2439 total_size += entry->bytes;
2440 BUG_ON(ret);
2441 } while (node && entry != last);
2442
2443 cluster->max_size = max_extent;
2444 trace_btrfs_setup_cluster(block_group, cluster, total_size, 0);
2445 return 0;
2446 }
2447
2448 /*
2449 * This specifically looks for bitmaps that may work in the cluster, we assume
2450 * that we have already failed to find extents that will work.
2451 */
2452 static noinline int
2453 setup_cluster_bitmap(struct btrfs_block_group_cache *block_group,
2454 struct btrfs_free_cluster *cluster,
2455 struct list_head *bitmaps, u64 offset, u64 bytes,
2456 u64 cont1_bytes, u64 min_bytes)
2457 {
2458 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2459 struct btrfs_free_space *entry;
2460 int ret = -ENOSPC;
2461 u64 bitmap_offset = offset_to_bitmap(ctl, offset);
2462
2463 if (ctl->total_bitmaps == 0)
2464 return -ENOSPC;
2465
2466 /*
2467 * The bitmap that covers offset won't be in the list unless offset
2468 * is just its start offset.
2469 */
2470 entry = list_first_entry(bitmaps, struct btrfs_free_space, list);
2471 if (entry->offset != bitmap_offset) {
2472 entry = tree_search_offset(ctl, bitmap_offset, 1, 0);
2473 if (entry && list_empty(&entry->list))
2474 list_add(&entry->list, bitmaps);
2475 }
2476
2477 list_for_each_entry(entry, bitmaps, list) {
2478 if (entry->bytes < min_bytes)
2479 continue;
2480 ret = btrfs_bitmap_cluster(block_group, entry, cluster, offset,
2481 bytes, cont1_bytes, min_bytes);
2482 if (!ret)
2483 return 0;
2484 }
2485
2486 /*
2487 * The bitmaps list has all the bitmaps that record free space
2488 * starting after offset, so no more search is required.
2489 */
2490 return -ENOSPC;
2491 }
2492
2493 /*
2494 * here we try to find a cluster of blocks in a block group. The goal
2495 * is to find at least bytes+empty_size.
2496 * We might not find them all in one contiguous area.
2497 *
2498 * returns zero and sets up cluster if things worked out, otherwise
2499 * it returns -enospc
2500 */
2501 int btrfs_find_space_cluster(struct btrfs_trans_handle *trans,
2502 struct btrfs_root *root,
2503 struct btrfs_block_group_cache *block_group,
2504 struct btrfs_free_cluster *cluster,
2505 u64 offset, u64 bytes, u64 empty_size)
2506 {
2507 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2508 struct btrfs_free_space *entry, *tmp;
2509 LIST_HEAD(bitmaps);
2510 u64 min_bytes;
2511 u64 cont1_bytes;
2512 int ret;
2513
2514 /*
2515 * Choose the minimum extent size we'll require for this
2516 * cluster. For SSD_SPREAD, don't allow any fragmentation.
2517 * For metadata, allow allocates with smaller extents. For
2518 * data, keep it dense.
2519 */
2520 if (btrfs_test_opt(root, SSD_SPREAD)) {
2521 cont1_bytes = min_bytes = bytes + empty_size;
2522 } else if (block_group->flags & BTRFS_BLOCK_GROUP_METADATA) {
2523 cont1_bytes = bytes;
2524 min_bytes = block_group->sectorsize;
2525 } else {
2526 cont1_bytes = max(bytes, (bytes + empty_size) >> 2);
2527 min_bytes = block_group->sectorsize;
2528 }
2529
2530 spin_lock(&ctl->tree_lock);
2531
2532 /*
2533 * If we know we don't have enough space to make a cluster don't even
2534 * bother doing all the work to try and find one.
2535 */
2536 if (ctl->free_space < bytes) {
2537 spin_unlock(&ctl->tree_lock);
2538 return -ENOSPC;
2539 }
2540
2541 spin_lock(&cluster->lock);
2542
2543 /* someone already found a cluster, hooray */
2544 if (cluster->block_group) {
2545 ret = 0;
2546 goto out;
2547 }
2548
2549 trace_btrfs_find_cluster(block_group, offset, bytes, empty_size,
2550 min_bytes);
2551
2552 INIT_LIST_HEAD(&bitmaps);
2553 ret = setup_cluster_no_bitmap(block_group, cluster, &bitmaps, offset,
2554 bytes + empty_size,
2555 cont1_bytes, min_bytes);
2556 if (ret)
2557 ret = setup_cluster_bitmap(block_group, cluster, &bitmaps,
2558 offset, bytes + empty_size,
2559 cont1_bytes, min_bytes);
2560
2561 /* Clear our temporary list */
2562 list_for_each_entry_safe(entry, tmp, &bitmaps, list)
2563 list_del_init(&entry->list);
2564
2565 if (!ret) {
2566 atomic_inc(&block_group->count);
2567 list_add_tail(&cluster->block_group_list,
2568 &block_group->cluster_list);
2569 cluster->block_group = block_group;
2570 } else {
2571 trace_btrfs_failed_cluster_setup(block_group);
2572 }
2573 out:
2574 spin_unlock(&cluster->lock);
2575 spin_unlock(&ctl->tree_lock);
2576
2577 return ret;
2578 }
2579
2580 /*
2581 * simple code to zero out a cluster
2582 */
2583 void btrfs_init_free_cluster(struct btrfs_free_cluster *cluster)
2584 {
2585 spin_lock_init(&cluster->lock);
2586 spin_lock_init(&cluster->refill_lock);
2587 cluster->root = RB_ROOT;
2588 cluster->max_size = 0;
2589 INIT_LIST_HEAD(&cluster->block_group_list);
2590 cluster->block_group = NULL;
2591 }
2592
2593 static int do_trimming(struct btrfs_block_group_cache *block_group,
2594 u64 *total_trimmed, u64 start, u64 bytes,
2595 u64 reserved_start, u64 reserved_bytes)
2596 {
2597 struct btrfs_space_info *space_info = block_group->space_info;
2598 struct btrfs_fs_info *fs_info = block_group->fs_info;
2599 int ret;
2600 int update = 0;
2601 u64 trimmed = 0;
2602
2603 spin_lock(&space_info->lock);
2604 spin_lock(&block_group->lock);
2605 if (!block_group->ro) {
2606 block_group->reserved += reserved_bytes;
2607 space_info->bytes_reserved += reserved_bytes;
2608 update = 1;
2609 }
2610 spin_unlock(&block_group->lock);
2611 spin_unlock(&space_info->lock);
2612
2613 ret = btrfs_error_discard_extent(fs_info->extent_root,
2614 start, bytes, &trimmed);
2615 if (!ret)
2616 *total_trimmed += trimmed;
2617
2618 btrfs_add_free_space(block_group, reserved_start, reserved_bytes);
2619
2620 if (update) {
2621 spin_lock(&space_info->lock);
2622 spin_lock(&block_group->lock);
2623 if (block_group->ro)
2624 space_info->bytes_readonly += reserved_bytes;
2625 block_group->reserved -= reserved_bytes;
2626 space_info->bytes_reserved -= reserved_bytes;
2627 spin_unlock(&space_info->lock);
2628 spin_unlock(&block_group->lock);
2629 }
2630
2631 return ret;
2632 }
2633
2634 static int trim_no_bitmap(struct btrfs_block_group_cache *block_group,
2635 u64 *total_trimmed, u64 start, u64 end, u64 minlen)
2636 {
2637 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2638 struct btrfs_free_space *entry;
2639 struct rb_node *node;
2640 int ret = 0;
2641 u64 extent_start;
2642 u64 extent_bytes;
2643 u64 bytes;
2644
2645 while (start < end) {
2646 spin_lock(&ctl->tree_lock);
2647
2648 if (ctl->free_space < minlen) {
2649 spin_unlock(&ctl->tree_lock);
2650 break;
2651 }
2652
2653 entry = tree_search_offset(ctl, start, 0, 1);
2654 if (!entry) {
2655 spin_unlock(&ctl->tree_lock);
2656 break;
2657 }
2658
2659 /* skip bitmaps */
2660 while (entry->bitmap) {
2661 node = rb_next(&entry->offset_index);
2662 if (!node) {
2663 spin_unlock(&ctl->tree_lock);
2664 goto out;
2665 }
2666 entry = rb_entry(node, struct btrfs_free_space,
2667 offset_index);
2668 }
2669
2670 if (entry->offset >= end) {
2671 spin_unlock(&ctl->tree_lock);
2672 break;
2673 }
2674
2675 extent_start = entry->offset;
2676 extent_bytes = entry->bytes;
2677 start = max(start, extent_start);
2678 bytes = min(extent_start + extent_bytes, end) - start;
2679 if (bytes < minlen) {
2680 spin_unlock(&ctl->tree_lock);
2681 goto next;
2682 }
2683
2684 unlink_free_space(ctl, entry);
2685 kmem_cache_free(btrfs_free_space_cachep, entry);
2686
2687 spin_unlock(&ctl->tree_lock);
2688
2689 ret = do_trimming(block_group, total_trimmed, start, bytes,
2690 extent_start, extent_bytes);
2691 if (ret)
2692 break;
2693 next:
2694 start += bytes;
2695
2696 if (fatal_signal_pending(current)) {
2697 ret = -ERESTARTSYS;
2698 break;
2699 }
2700
2701 cond_resched();
2702 }
2703 out:
2704 return ret;
2705 }
2706
2707 static int trim_bitmaps(struct btrfs_block_group_cache *block_group,
2708 u64 *total_trimmed, u64 start, u64 end, u64 minlen)
2709 {
2710 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2711 struct btrfs_free_space *entry;
2712 int ret = 0;
2713 int ret2;
2714 u64 bytes;
2715 u64 offset = offset_to_bitmap(ctl, start);
2716
2717 while (offset < end) {
2718 bool next_bitmap = false;
2719
2720 spin_lock(&ctl->tree_lock);
2721
2722 if (ctl->free_space < minlen) {
2723 spin_unlock(&ctl->tree_lock);
2724 break;
2725 }
2726
2727 entry = tree_search_offset(ctl, offset, 1, 0);
2728 if (!entry) {
2729 spin_unlock(&ctl->tree_lock);
2730 next_bitmap = true;
2731 goto next;
2732 }
2733
2734 bytes = minlen;
2735 ret2 = search_bitmap(ctl, entry, &start, &bytes);
2736 if (ret2 || start >= end) {
2737 spin_unlock(&ctl->tree_lock);
2738 next_bitmap = true;
2739 goto next;
2740 }
2741
2742 bytes = min(bytes, end - start);
2743 if (bytes < minlen) {
2744 spin_unlock(&ctl->tree_lock);
2745 goto next;
2746 }
2747
2748 bitmap_clear_bits(ctl, entry, start, bytes);
2749 if (entry->bytes == 0)
2750 free_bitmap(ctl, entry);
2751
2752 spin_unlock(&ctl->tree_lock);
2753
2754 ret = do_trimming(block_group, total_trimmed, start, bytes,
2755 start, bytes);
2756 if (ret)
2757 break;
2758 next:
2759 if (next_bitmap) {
2760 offset += BITS_PER_BITMAP * ctl->unit;
2761 } else {
2762 start += bytes;
2763 if (start >= offset + BITS_PER_BITMAP * ctl->unit)
2764 offset += BITS_PER_BITMAP * ctl->unit;
2765 }
2766
2767 if (fatal_signal_pending(current)) {
2768 ret = -ERESTARTSYS;
2769 break;
2770 }
2771
2772 cond_resched();
2773 }
2774
2775 return ret;
2776 }
2777
2778 int btrfs_trim_block_group(struct btrfs_block_group_cache *block_group,
2779 u64 *trimmed, u64 start, u64 end, u64 minlen)
2780 {
2781 int ret;
2782
2783 *trimmed = 0;
2784
2785 ret = trim_no_bitmap(block_group, trimmed, start, end, minlen);
2786 if (ret)
2787 return ret;
2788
2789 ret = trim_bitmaps(block_group, trimmed, start, end, minlen);
2790
2791 return ret;
2792 }
2793
2794 /*
2795 * Find the left-most item in the cache tree, and then return the
2796 * smallest inode number in the item.
2797 *
2798 * Note: the returned inode number may not be the smallest one in
2799 * the tree, if the left-most item is a bitmap.
2800 */
2801 u64 btrfs_find_ino_for_alloc(struct btrfs_root *fs_root)
2802 {
2803 struct btrfs_free_space_ctl *ctl = fs_root->free_ino_ctl;
2804 struct btrfs_free_space *entry = NULL;
2805 u64 ino = 0;
2806
2807 spin_lock(&ctl->tree_lock);
2808
2809 if (RB_EMPTY_ROOT(&ctl->free_space_offset))
2810 goto out;
2811
2812 entry = rb_entry(rb_first(&ctl->free_space_offset),
2813 struct btrfs_free_space, offset_index);
2814
2815 if (!entry->bitmap) {
2816 ino = entry->offset;
2817
2818 unlink_free_space(ctl, entry);
2819 entry->offset++;
2820 entry->bytes--;
2821 if (!entry->bytes)
2822 kmem_cache_free(btrfs_free_space_cachep, entry);
2823 else
2824 link_free_space(ctl, entry);
2825 } else {
2826 u64 offset = 0;
2827 u64 count = 1;
2828 int ret;
2829
2830 ret = search_bitmap(ctl, entry, &offset, &count);
2831 BUG_ON(ret);
2832
2833 ino = offset;
2834 bitmap_clear_bits(ctl, entry, offset, 1);
2835 if (entry->bytes == 0)
2836 free_bitmap(ctl, entry);
2837 }
2838 out:
2839 spin_unlock(&ctl->tree_lock);
2840
2841 return ino;
2842 }
2843
2844 struct inode *lookup_free_ino_inode(struct btrfs_root *root,
2845 struct btrfs_path *path)
2846 {
2847 struct inode *inode = NULL;
2848
2849 spin_lock(&root->cache_lock);
2850 if (root->cache_inode)
2851 inode = igrab(root->cache_inode);
2852 spin_unlock(&root->cache_lock);
2853 if (inode)
2854 return inode;
2855
2856 inode = __lookup_free_space_inode(root, path, 0);
2857 if (IS_ERR(inode))
2858 return inode;
2859
2860 spin_lock(&root->cache_lock);
2861 if (!btrfs_fs_closing(root->fs_info))
2862 root->cache_inode = igrab(inode);
2863 spin_unlock(&root->cache_lock);
2864
2865 return inode;
2866 }
2867
2868 int create_free_ino_inode(struct btrfs_root *root,
2869 struct btrfs_trans_handle *trans,
2870 struct btrfs_path *path)
2871 {
2872 return __create_free_space_inode(root, trans, path,
2873 BTRFS_FREE_INO_OBJECTID, 0);
2874 }
2875
2876 int load_free_ino_cache(struct btrfs_fs_info *fs_info, struct btrfs_root *root)
2877 {
2878 struct btrfs_free_space_ctl *ctl = root->free_ino_ctl;
2879 struct btrfs_path *path;
2880 struct inode *inode;
2881 int ret = 0;
2882 u64 root_gen = btrfs_root_generation(&root->root_item);
2883
2884 if (!btrfs_test_opt(root, INODE_MAP_CACHE))
2885 return 0;
2886
2887 /*
2888 * If we're unmounting then just return, since this does a search on the
2889 * normal root and not the commit root and we could deadlock.
2890 */
2891 if (btrfs_fs_closing(fs_info))
2892 return 0;
2893
2894 path = btrfs_alloc_path();
2895 if (!path)
2896 return 0;
2897
2898 inode = lookup_free_ino_inode(root, path);
2899 if (IS_ERR(inode))
2900 goto out;
2901
2902 if (root_gen != BTRFS_I(inode)->generation)
2903 goto out_put;
2904
2905 ret = __load_free_space_cache(root, inode, ctl, path, 0);
2906
2907 if (ret < 0)
2908 printk(KERN_ERR "btrfs: failed to load free ino cache for "
2909 "root %llu\n", root->root_key.objectid);
2910 out_put:
2911 iput(inode);
2912 out:
2913 btrfs_free_path(path);
2914 return ret;
2915 }
2916
2917 int btrfs_write_out_ino_cache(struct btrfs_root *root,
2918 struct btrfs_trans_handle *trans,
2919 struct btrfs_path *path)
2920 {
2921 struct btrfs_free_space_ctl *ctl = root->free_ino_ctl;
2922 struct inode *inode;
2923 int ret;
2924
2925 if (!btrfs_test_opt(root, INODE_MAP_CACHE))
2926 return 0;
2927
2928 inode = lookup_free_ino_inode(root, path);
2929 if (IS_ERR(inode))
2930 return 0;
2931
2932 ret = __btrfs_write_out_cache(root, inode, ctl, NULL, trans, path, 0);
2933 if (ret) {
2934 btrfs_delalloc_release_metadata(inode, inode->i_size);
2935 #ifdef DEBUG
2936 printk(KERN_ERR "btrfs: failed to write free ino cache "
2937 "for root %llu\n", root->root_key.objectid);
2938 #endif
2939 }
2940
2941 iput(inode);
2942 return ret;
2943 }
Linus' kernel tree