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Merge tag 'gpio-for-v3.11-3' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw...
[linux-2.6.git] / fs / btrfs / free-space-cache.c
blobb21a3cd667d8cc656878b8d462aa7cd45ebc8435
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 static void unlink_free_space(struct btrfs_free_space_ctl *ctl,
37 struct btrfs_free_space *info);
38
39 static struct inode *__lookup_free_space_inode(struct btrfs_root *root,
40 struct btrfs_path *path,
41 u64 offset)
42 {
43 struct btrfs_key key;
44 struct btrfs_key location;
45 struct btrfs_disk_key disk_key;
46 struct btrfs_free_space_header *header;
47 struct extent_buffer *leaf;
48 struct inode *inode = NULL;
49 int ret;
50
51 key.objectid = BTRFS_FREE_SPACE_OBJECTID;
52 key.offset = offset;
53 key.type = 0;
54
55 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
56 if (ret < 0)
57 return ERR_PTR(ret);
58 if (ret > 0) {
59 btrfs_release_path(path);
60 return ERR_PTR(-ENOENT);
61 }
62
63 leaf = path->nodes[0];
64 header = btrfs_item_ptr(leaf, path->slots[0],
65 struct btrfs_free_space_header);
66 btrfs_free_space_key(leaf, header, &disk_key);
67 btrfs_disk_key_to_cpu(&location, &disk_key);
68 btrfs_release_path(path);
69
70 inode = btrfs_iget(root->fs_info->sb, &location, root, NULL);
71 if (!inode)
72 return ERR_PTR(-ENOENT);
73 if (IS_ERR(inode))
74 return inode;
75 if (is_bad_inode(inode)) {
76 iput(inode);
77 return ERR_PTR(-ENOENT);
78 }
79
80 mapping_set_gfp_mask(inode->i_mapping,
81 mapping_gfp_mask(inode->i_mapping) & ~__GFP_FS);
82
83 return inode;
84 }
85
86 struct inode *lookup_free_space_inode(struct btrfs_root *root,
87 struct btrfs_block_group_cache
88 *block_group, struct btrfs_path *path)
89 {
90 struct inode *inode = NULL;
91 u32 flags = BTRFS_INODE_NODATASUM | BTRFS_INODE_NODATACOW;
92
93 spin_lock(&block_group->lock);
94 if (block_group->inode)
95 inode = igrab(block_group->inode);
96 spin_unlock(&block_group->lock);
97 if (inode)
98 return inode;
99
100 inode = __lookup_free_space_inode(root, path,
101 block_group->key.objectid);
102 if (IS_ERR(inode))
103 return inode;
104
105 spin_lock(&block_group->lock);
106 if (!((BTRFS_I(inode)->flags & flags) == flags)) {
107 btrfs_info(root->fs_info,
108 "Old style space inode found, converting.");
109 BTRFS_I(inode)->flags |= BTRFS_INODE_NODATASUM |
110 BTRFS_INODE_NODATACOW;
111 block_group->disk_cache_state = BTRFS_DC_CLEAR;
112 }
113
114 if (!block_group->iref) {
115 block_group->inode = igrab(inode);
116 block_group->iref = 1;
117 }
118 spin_unlock(&block_group->lock);
119
120 return inode;
121 }
122
123 static int __create_free_space_inode(struct btrfs_root *root,
124 struct btrfs_trans_handle *trans,
125 struct btrfs_path *path,
126 u64 ino, u64 offset)
127 {
128 struct btrfs_key key;
129 struct btrfs_disk_key disk_key;
130 struct btrfs_free_space_header *header;
131 struct btrfs_inode_item *inode_item;
132 struct extent_buffer *leaf;
133 u64 flags = BTRFS_INODE_NOCOMPRESS | BTRFS_INODE_PREALLOC;
134 int ret;
135
136 ret = btrfs_insert_empty_inode(trans, root, path, ino);
137 if (ret)
138 return ret;
139
140 /* We inline crc's for the free disk space cache */
141 if (ino != BTRFS_FREE_INO_OBJECTID)
142 flags |= BTRFS_INODE_NODATASUM | BTRFS_INODE_NODATACOW;
143
144 leaf = path->nodes[0];
145 inode_item = btrfs_item_ptr(leaf, path->slots[0],
146 struct btrfs_inode_item);
147 btrfs_item_key(leaf, &disk_key, path->slots[0]);
148 memset_extent_buffer(leaf, 0, (unsigned long)inode_item,
149 sizeof(*inode_item));
150 btrfs_set_inode_generation(leaf, inode_item, trans->transid);
151 btrfs_set_inode_size(leaf, inode_item, 0);
152 btrfs_set_inode_nbytes(leaf, inode_item, 0);
153 btrfs_set_inode_uid(leaf, inode_item, 0);
154 btrfs_set_inode_gid(leaf, inode_item, 0);
155 btrfs_set_inode_mode(leaf, inode_item, S_IFREG | 0600);
156 btrfs_set_inode_flags(leaf, inode_item, flags);
157 btrfs_set_inode_nlink(leaf, inode_item, 1);
158 btrfs_set_inode_transid(leaf, inode_item, trans->transid);
159 btrfs_set_inode_block_group(leaf, inode_item, offset);
160 btrfs_mark_buffer_dirty(leaf);
161 btrfs_release_path(path);
162
163 key.objectid = BTRFS_FREE_SPACE_OBJECTID;
164 key.offset = offset;
165 key.type = 0;
166
167 ret = btrfs_insert_empty_item(trans, root, path, &key,
168 sizeof(struct btrfs_free_space_header));
169 if (ret < 0) {
170 btrfs_release_path(path);
171 return ret;
172 }
173 leaf = path->nodes[0];
174 header = btrfs_item_ptr(leaf, path->slots[0],
175 struct btrfs_free_space_header);
176 memset_extent_buffer(leaf, 0, (unsigned long)header, sizeof(*header));
177 btrfs_set_free_space_key(leaf, header, &disk_key);
178 btrfs_mark_buffer_dirty(leaf);
179 btrfs_release_path(path);
180
181 return 0;
182 }
183
184 int create_free_space_inode(struct btrfs_root *root,
185 struct btrfs_trans_handle *trans,
186 struct btrfs_block_group_cache *block_group,
187 struct btrfs_path *path)
188 {
189 int ret;
190 u64 ino;
191
192 ret = btrfs_find_free_objectid(root, &ino);
193 if (ret < 0)
194 return ret;
195
196 return __create_free_space_inode(root, trans, path, ino,
197 block_group->key.objectid);
198 }
199
200 int btrfs_check_trunc_cache_free_space(struct btrfs_root *root,
201 struct btrfs_block_rsv *rsv)
202 {
203 u64 needed_bytes;
204 int ret;
205
206 /* 1 for slack space, 1 for updating the inode */
207 needed_bytes = btrfs_calc_trunc_metadata_size(root, 1) +
208 btrfs_calc_trans_metadata_size(root, 1);
209
210 spin_lock(&rsv->lock);
211 if (rsv->reserved < needed_bytes)
212 ret = -ENOSPC;
213 else
214 ret = 0;
215 spin_unlock(&rsv->lock);
216 return ret;
217 }
218
219 int btrfs_truncate_free_space_cache(struct btrfs_root *root,
220 struct btrfs_trans_handle *trans,
221 struct btrfs_path *path,
222 struct inode *inode)
223 {
224 loff_t oldsize;
225 int ret = 0;
226
227 oldsize = i_size_read(inode);
228 btrfs_i_size_write(inode, 0);
229 truncate_pagecache(inode, oldsize, 0);
230
231 /*
232 * We don't need an orphan item because truncating the free space cache
233 * will never be split across transactions.
234 */
235 ret = btrfs_truncate_inode_items(trans, root, inode,
236 0, BTRFS_EXTENT_DATA_KEY);
237 if (ret) {
238 btrfs_abort_transaction(trans, root, ret);
239 return ret;
240 }
241
242 ret = btrfs_update_inode(trans, root, inode);
243 if (ret)
244 btrfs_abort_transaction(trans, root, ret);
245
246 return ret;
247 }
248
249 static int readahead_cache(struct inode *inode)
250 {
251 struct file_ra_state *ra;
252 unsigned long last_index;
253
254 ra = kzalloc(sizeof(*ra), GFP_NOFS);
255 if (!ra)
256 return -ENOMEM;
257
258 file_ra_state_init(ra, inode->i_mapping);
259 last_index = (i_size_read(inode) - 1) >> PAGE_CACHE_SHIFT;
260
261 page_cache_sync_readahead(inode->i_mapping, ra, NULL, 0, last_index);
262
263 kfree(ra);
264
265 return 0;
266 }
267
268 struct io_ctl {
269 void *cur, *orig;
270 struct page *page;
271 struct page **pages;
272 struct btrfs_root *root;
273 unsigned long size;
274 int index;
275 int num_pages;
276 unsigned check_crcs:1;
277 };
278
279 static int io_ctl_init(struct io_ctl *io_ctl, struct inode *inode,
280 struct btrfs_root *root)
281 {
282 memset(io_ctl, 0, sizeof(struct io_ctl));
283 io_ctl->num_pages = (i_size_read(inode) + PAGE_CACHE_SIZE - 1) >>
284 PAGE_CACHE_SHIFT;
285 io_ctl->pages = kzalloc(sizeof(struct page *) * io_ctl->num_pages,
286 GFP_NOFS);
287 if (!io_ctl->pages)
288 return -ENOMEM;
289 io_ctl->root = root;
290 if (btrfs_ino(inode) != BTRFS_FREE_INO_OBJECTID)
291 io_ctl->check_crcs = 1;
292 return 0;
293 }
294
295 static void io_ctl_free(struct io_ctl *io_ctl)
296 {
297 kfree(io_ctl->pages);
298 }
299
300 static void io_ctl_unmap_page(struct io_ctl *io_ctl)
301 {
302 if (io_ctl->cur) {
303 kunmap(io_ctl->page);
304 io_ctl->cur = NULL;
305 io_ctl->orig = NULL;
306 }
307 }
308
309 static void io_ctl_map_page(struct io_ctl *io_ctl, int clear)
310 {
311 BUG_ON(io_ctl->index >= io_ctl->num_pages);
312 io_ctl->page = io_ctl->pages[io_ctl->index++];
313 io_ctl->cur = kmap(io_ctl->page);
314 io_ctl->orig = io_ctl->cur;
315 io_ctl->size = PAGE_CACHE_SIZE;
316 if (clear)
317 memset(io_ctl->cur, 0, PAGE_CACHE_SIZE);
318 }
319
320 static void io_ctl_drop_pages(struct io_ctl *io_ctl)
321 {
322 int i;
323
324 io_ctl_unmap_page(io_ctl);
325
326 for (i = 0; i < io_ctl->num_pages; i++) {
327 if (io_ctl->pages[i]) {
328 ClearPageChecked(io_ctl->pages[i]);
329 unlock_page(io_ctl->pages[i]);
330 page_cache_release(io_ctl->pages[i]);
331 }
332 }
333 }
334
335 static int io_ctl_prepare_pages(struct io_ctl *io_ctl, struct inode *inode,
336 int uptodate)
337 {
338 struct page *page;
339 gfp_t mask = btrfs_alloc_write_mask(inode->i_mapping);
340 int i;
341
342 for (i = 0; i < io_ctl->num_pages; i++) {
343 page = find_or_create_page(inode->i_mapping, i, mask);
344 if (!page) {
345 io_ctl_drop_pages(io_ctl);
346 return -ENOMEM;
347 }
348 io_ctl->pages[i] = page;
349 if (uptodate && !PageUptodate(page)) {
350 btrfs_readpage(NULL, page);
351 lock_page(page);
352 if (!PageUptodate(page)) {
353 printk(KERN_ERR "btrfs: error reading free "
354 "space cache\n");
355 io_ctl_drop_pages(io_ctl);
356 return -EIO;
357 }
358 }
359 }
360
361 for (i = 0; i < io_ctl->num_pages; i++) {
362 clear_page_dirty_for_io(io_ctl->pages[i]);
363 set_page_extent_mapped(io_ctl->pages[i]);
364 }
365
366 return 0;
367 }
368
369 static void io_ctl_set_generation(struct io_ctl *io_ctl, u64 generation)
370 {
371 __le64 *val;
372
373 io_ctl_map_page(io_ctl, 1);
374
375 /*
376 * Skip the csum areas. If we don't check crcs then we just have a
377 * 64bit chunk at the front of the first page.
378 */
379 if (io_ctl->check_crcs) {
380 io_ctl->cur += (sizeof(u32) * io_ctl->num_pages);
381 io_ctl->size -= sizeof(u64) + (sizeof(u32) * io_ctl->num_pages);
382 } else {
383 io_ctl->cur += sizeof(u64);
384 io_ctl->size -= sizeof(u64) * 2;
385 }
386
387 val = io_ctl->cur;
388 *val = cpu_to_le64(generation);
389 io_ctl->cur += sizeof(u64);
390 }
391
392 static int io_ctl_check_generation(struct io_ctl *io_ctl, u64 generation)
393 {
394 __le64 *gen;
395
396 /*
397 * Skip the crc area. If we don't check crcs then we just have a 64bit
398 * chunk at the front of the first page.
399 */
400 if (io_ctl->check_crcs) {
401 io_ctl->cur += sizeof(u32) * io_ctl->num_pages;
402 io_ctl->size -= sizeof(u64) +
403 (sizeof(u32) * io_ctl->num_pages);
404 } else {
405 io_ctl->cur += sizeof(u64);
406 io_ctl->size -= sizeof(u64) * 2;
407 }
408
409 gen = io_ctl->cur;
410 if (le64_to_cpu(*gen) != generation) {
411 printk_ratelimited(KERN_ERR "btrfs: space cache generation "
412 "(%Lu) does not match inode (%Lu)\n", *gen,
413 generation);
414 io_ctl_unmap_page(io_ctl);
415 return -EIO;
416 }
417 io_ctl->cur += sizeof(u64);
418 return 0;
419 }
420
421 static void io_ctl_set_crc(struct io_ctl *io_ctl, int index)
422 {
423 u32 *tmp;
424 u32 crc = ~(u32)0;
425 unsigned offset = 0;
426
427 if (!io_ctl->check_crcs) {
428 io_ctl_unmap_page(io_ctl);
429 return;
430 }
431
432 if (index == 0)
433 offset = sizeof(u32) * io_ctl->num_pages;
434
435 crc = btrfs_csum_data(io_ctl->orig + offset, crc,
436 PAGE_CACHE_SIZE - offset);
437 btrfs_csum_final(crc, (char *)&crc);
438 io_ctl_unmap_page(io_ctl);
439 tmp = kmap(io_ctl->pages[0]);
440 tmp += index;
441 *tmp = crc;
442 kunmap(io_ctl->pages[0]);
443 }
444
445 static int io_ctl_check_crc(struct io_ctl *io_ctl, int index)
446 {
447 u32 *tmp, val;
448 u32 crc = ~(u32)0;
449 unsigned offset = 0;
450
451 if (!io_ctl->check_crcs) {
452 io_ctl_map_page(io_ctl, 0);
453 return 0;
454 }
455
456 if (index == 0)
457 offset = sizeof(u32) * io_ctl->num_pages;
458
459 tmp = kmap(io_ctl->pages[0]);
460 tmp += index;
461 val = *tmp;
462 kunmap(io_ctl->pages[0]);
463
464 io_ctl_map_page(io_ctl, 0);
465 crc = btrfs_csum_data(io_ctl->orig + offset, crc,
466 PAGE_CACHE_SIZE - offset);
467 btrfs_csum_final(crc, (char *)&crc);
468 if (val != crc) {
469 printk_ratelimited(KERN_ERR "btrfs: csum mismatch on free "
470 "space cache\n");
471 io_ctl_unmap_page(io_ctl);
472 return -EIO;
473 }
474
475 return 0;
476 }
477
478 static int io_ctl_add_entry(struct io_ctl *io_ctl, u64 offset, u64 bytes,
479 void *bitmap)
480 {
481 struct btrfs_free_space_entry *entry;
482
483 if (!io_ctl->cur)
484 return -ENOSPC;
485
486 entry = io_ctl->cur;
487 entry->offset = cpu_to_le64(offset);
488 entry->bytes = cpu_to_le64(bytes);
489 entry->type = (bitmap) ? BTRFS_FREE_SPACE_BITMAP :
490 BTRFS_FREE_SPACE_EXTENT;
491 io_ctl->cur += sizeof(struct btrfs_free_space_entry);
492 io_ctl->size -= sizeof(struct btrfs_free_space_entry);
493
494 if (io_ctl->size >= sizeof(struct btrfs_free_space_entry))
495 return 0;
496
497 io_ctl_set_crc(io_ctl, io_ctl->index - 1);
498
499 /* No more pages to map */
500 if (io_ctl->index >= io_ctl->num_pages)
501 return 0;
502
503 /* map the next page */
504 io_ctl_map_page(io_ctl, 1);
505 return 0;
506 }
507
508 static int io_ctl_add_bitmap(struct io_ctl *io_ctl, void *bitmap)
509 {
510 if (!io_ctl->cur)
511 return -ENOSPC;
512
513 /*
514 * If we aren't at the start of the current page, unmap this one and
515 * map the next one if there is any left.
516 */
517 if (io_ctl->cur != io_ctl->orig) {
518 io_ctl_set_crc(io_ctl, io_ctl->index - 1);
519 if (io_ctl->index >= io_ctl->num_pages)
520 return -ENOSPC;
521 io_ctl_map_page(io_ctl, 0);
522 }
523
524 memcpy(io_ctl->cur, bitmap, PAGE_CACHE_SIZE);
525 io_ctl_set_crc(io_ctl, io_ctl->index - 1);
526 if (io_ctl->index < io_ctl->num_pages)
527 io_ctl_map_page(io_ctl, 0);
528 return 0;
529 }
530
531 static void io_ctl_zero_remaining_pages(struct io_ctl *io_ctl)
532 {
533 /*
534 * If we're not on the boundary we know we've modified the page and we
535 * need to crc the page.
536 */
537 if (io_ctl->cur != io_ctl->orig)
538 io_ctl_set_crc(io_ctl, io_ctl->index - 1);
539 else
540 io_ctl_unmap_page(io_ctl);
541
542 while (io_ctl->index < io_ctl->num_pages) {
543 io_ctl_map_page(io_ctl, 1);
544 io_ctl_set_crc(io_ctl, io_ctl->index - 1);
545 }
546 }
547
548 static int io_ctl_read_entry(struct io_ctl *io_ctl,
549 struct btrfs_free_space *entry, u8 *type)
550 {
551 struct btrfs_free_space_entry *e;
552 int ret;
553
554 if (!io_ctl->cur) {
555 ret = io_ctl_check_crc(io_ctl, io_ctl->index);
556 if (ret)
557 return ret;
558 }
559
560 e = io_ctl->cur;
561 entry->offset = le64_to_cpu(e->offset);
562 entry->bytes = le64_to_cpu(e->bytes);
563 *type = e->type;
564 io_ctl->cur += sizeof(struct btrfs_free_space_entry);
565 io_ctl->size -= sizeof(struct btrfs_free_space_entry);
566
567 if (io_ctl->size >= sizeof(struct btrfs_free_space_entry))
568 return 0;
569
570 io_ctl_unmap_page(io_ctl);
571
572 return 0;
573 }
574
575 static int io_ctl_read_bitmap(struct io_ctl *io_ctl,
576 struct btrfs_free_space *entry)
577 {
578 int ret;
579
580 ret = io_ctl_check_crc(io_ctl, io_ctl->index);
581 if (ret)
582 return ret;
583
584 memcpy(entry->bitmap, io_ctl->cur, PAGE_CACHE_SIZE);
585 io_ctl_unmap_page(io_ctl);
586
587 return 0;
588 }
589
590 /*
591 * Since we attach pinned extents after the fact we can have contiguous sections
592 * of free space that are split up in entries. This poses a problem with the
593 * tree logging stuff since it could have allocated across what appears to be 2
594 * entries since we would have merged the entries when adding the pinned extents
595 * back to the free space cache. So run through the space cache that we just
596 * loaded and merge contiguous entries. This will make the log replay stuff not
597 * blow up and it will make for nicer allocator behavior.
598 */
599 static void merge_space_tree(struct btrfs_free_space_ctl *ctl)
600 {
601 struct btrfs_free_space *e, *prev = NULL;
602 struct rb_node *n;
603
604 again:
605 spin_lock(&ctl->tree_lock);
606 for (n = rb_first(&ctl->free_space_offset); n; n = rb_next(n)) {
607 e = rb_entry(n, struct btrfs_free_space, offset_index);
608 if (!prev)
609 goto next;
610 if (e->bitmap || prev->bitmap)
611 goto next;
612 if (prev->offset + prev->bytes == e->offset) {
613 unlink_free_space(ctl, prev);
614 unlink_free_space(ctl, e);
615 prev->bytes += e->bytes;
616 kmem_cache_free(btrfs_free_space_cachep, e);
617 link_free_space(ctl, prev);
618 prev = NULL;
619 spin_unlock(&ctl->tree_lock);
620 goto again;
621 }
622 next:
623 prev = e;
624 }
625 spin_unlock(&ctl->tree_lock);
626 }
627
628 static int __load_free_space_cache(struct btrfs_root *root, struct inode *inode,
629 struct btrfs_free_space_ctl *ctl,
630 struct btrfs_path *path, u64 offset)
631 {
632 struct btrfs_free_space_header *header;
633 struct extent_buffer *leaf;
634 struct io_ctl io_ctl;
635 struct btrfs_key key;
636 struct btrfs_free_space *e, *n;
637 struct list_head bitmaps;
638 u64 num_entries;
639 u64 num_bitmaps;
640 u64 generation;
641 u8 type;
642 int ret = 0;
643
644 INIT_LIST_HEAD(&bitmaps);
645
646 /* Nothing in the space cache, goodbye */
647 if (!i_size_read(inode))
648 return 0;
649
650 key.objectid = BTRFS_FREE_SPACE_OBJECTID;
651 key.offset = offset;
652 key.type = 0;
653
654 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
655 if (ret < 0)
656 return 0;
657 else if (ret > 0) {
658 btrfs_release_path(path);
659 return 0;
660 }
661
662 ret = -1;
663
664 leaf = path->nodes[0];
665 header = btrfs_item_ptr(leaf, path->slots[0],
666 struct btrfs_free_space_header);
667 num_entries = btrfs_free_space_entries(leaf, header);
668 num_bitmaps = btrfs_free_space_bitmaps(leaf, header);
669 generation = btrfs_free_space_generation(leaf, header);
670 btrfs_release_path(path);
671
672 if (BTRFS_I(inode)->generation != generation) {
673 btrfs_err(root->fs_info,
674 "free space inode generation (%llu) "
675 "did not match free space cache generation (%llu)",
676 (unsigned long long)BTRFS_I(inode)->generation,
677 (unsigned long long)generation);
678 return 0;
679 }
680
681 if (!num_entries)
682 return 0;
683
684 ret = io_ctl_init(&io_ctl, inode, root);
685 if (ret)
686 return ret;
687
688 ret = readahead_cache(inode);
689 if (ret)
690 goto out;
691
692 ret = io_ctl_prepare_pages(&io_ctl, inode, 1);
693 if (ret)
694 goto out;
695
696 ret = io_ctl_check_crc(&io_ctl, 0);
697 if (ret)
698 goto free_cache;
699
700 ret = io_ctl_check_generation(&io_ctl, generation);
701 if (ret)
702 goto free_cache;
703
704 while (num_entries) {
705 e = kmem_cache_zalloc(btrfs_free_space_cachep,
706 GFP_NOFS);
707 if (!e)
708 goto free_cache;
709
710 ret = io_ctl_read_entry(&io_ctl, e, &type);
711 if (ret) {
712 kmem_cache_free(btrfs_free_space_cachep, e);
713 goto free_cache;
714 }
715
716 if (!e->bytes) {
717 kmem_cache_free(btrfs_free_space_cachep, e);
718 goto free_cache;
719 }
720
721 if (type == BTRFS_FREE_SPACE_EXTENT) {
722 spin_lock(&ctl->tree_lock);
723 ret = link_free_space(ctl, e);
724 spin_unlock(&ctl->tree_lock);
725 if (ret) {
726 btrfs_err(root->fs_info,
727 "Duplicate entries in free space cache, dumping");
728 kmem_cache_free(btrfs_free_space_cachep, e);
729 goto free_cache;
730 }
731 } else {
732 BUG_ON(!num_bitmaps);
733 num_bitmaps--;
734 e->bitmap = kzalloc(PAGE_CACHE_SIZE, GFP_NOFS);
735 if (!e->bitmap) {
736 kmem_cache_free(
737 btrfs_free_space_cachep, e);
738 goto free_cache;
739 }
740 spin_lock(&ctl->tree_lock);
741 ret = link_free_space(ctl, e);
742 ctl->total_bitmaps++;
743 ctl->op->recalc_thresholds(ctl);
744 spin_unlock(&ctl->tree_lock);
745 if (ret) {
746 btrfs_err(root->fs_info,
747 "Duplicate entries in free space cache, dumping");
748 kmem_cache_free(btrfs_free_space_cachep, e);
749 goto free_cache;
750 }
751 list_add_tail(&e->list, &bitmaps);
752 }
753
754 num_entries--;
755 }
756
757 io_ctl_unmap_page(&io_ctl);
758
759 /*
760 * We add the bitmaps at the end of the entries in order that
761 * the bitmap entries are added to the cache.
762 */
763 list_for_each_entry_safe(e, n, &bitmaps, list) {
764 list_del_init(&e->list);
765 ret = io_ctl_read_bitmap(&io_ctl, e);
766 if (ret)
767 goto free_cache;
768 }
769
770 io_ctl_drop_pages(&io_ctl);
771 merge_space_tree(ctl);
772 ret = 1;
773 out:
774 io_ctl_free(&io_ctl);
775 return ret;
776 free_cache:
777 io_ctl_drop_pages(&io_ctl);
778 __btrfs_remove_free_space_cache(ctl);
779 goto out;
780 }
781
782 int load_free_space_cache(struct btrfs_fs_info *fs_info,
783 struct btrfs_block_group_cache *block_group)
784 {
785 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
786 struct btrfs_root *root = fs_info->tree_root;
787 struct inode *inode;
788 struct btrfs_path *path;
789 int ret = 0;
790 bool matched;
791 u64 used = btrfs_block_group_used(&block_group->item);
792
793 /*
794 * If this block group has been marked to be cleared for one reason or
795 * another then we can't trust the on disk cache, so just return.
796 */
797 spin_lock(&block_group->lock);
798 if (block_group->disk_cache_state != BTRFS_DC_WRITTEN) {
799 spin_unlock(&block_group->lock);
800 return 0;
801 }
802 spin_unlock(&block_group->lock);
803
804 path = btrfs_alloc_path();
805 if (!path)
806 return 0;
807 path->search_commit_root = 1;
808 path->skip_locking = 1;
809
810 inode = lookup_free_space_inode(root, block_group, path);
811 if (IS_ERR(inode)) {
812 btrfs_free_path(path);
813 return 0;
814 }
815
816 /* We may have converted the inode and made the cache invalid. */
817 spin_lock(&block_group->lock);
818 if (block_group->disk_cache_state != BTRFS_DC_WRITTEN) {
819 spin_unlock(&block_group->lock);
820 btrfs_free_path(path);
821 goto out;
822 }
823 spin_unlock(&block_group->lock);
824
825 ret = __load_free_space_cache(fs_info->tree_root, inode, ctl,
826 path, block_group->key.objectid);
827 btrfs_free_path(path);
828 if (ret <= 0)
829 goto out;
830
831 spin_lock(&ctl->tree_lock);
832 matched = (ctl->free_space == (block_group->key.offset - used -
833 block_group->bytes_super));
834 spin_unlock(&ctl->tree_lock);
835
836 if (!matched) {
837 __btrfs_remove_free_space_cache(ctl);
838 btrfs_err(fs_info, "block group %llu has wrong amount of free space",
839 block_group->key.objectid);
840 ret = -1;
841 }
842 out:
843 if (ret < 0) {
844 /* This cache is bogus, make sure it gets cleared */
845 spin_lock(&block_group->lock);
846 block_group->disk_cache_state = BTRFS_DC_CLEAR;
847 spin_unlock(&block_group->lock);
848 ret = 0;
849
850 btrfs_err(fs_info, "failed to load free space cache for block group %llu",
851 block_group->key.objectid);
852 }
853
854 iput(inode);
855 return ret;
856 }
857
858 /**
859 * __btrfs_write_out_cache - write out cached info to an inode
860 * @root - the root the inode belongs to
861 * @ctl - the free space cache we are going to write out
862 * @block_group - the block_group for this cache if it belongs to a block_group
863 * @trans - the trans handle
864 * @path - the path to use
865 * @offset - the offset for the key we'll insert
866 *
867 * This function writes out a free space cache struct to disk for quick recovery
868 * on mount. This will return 0 if it was successfull in writing the cache out,
869 * and -1 if it was not.
870 */
871 static int __btrfs_write_out_cache(struct btrfs_root *root, struct inode *inode,
872 struct btrfs_free_space_ctl *ctl,
873 struct btrfs_block_group_cache *block_group,
874 struct btrfs_trans_handle *trans,
875 struct btrfs_path *path, u64 offset)
876 {
877 struct btrfs_free_space_header *header;
878 struct extent_buffer *leaf;
879 struct rb_node *node;
880 struct list_head *pos, *n;
881 struct extent_state *cached_state = NULL;
882 struct btrfs_free_cluster *cluster = NULL;
883 struct extent_io_tree *unpin = NULL;
884 struct io_ctl io_ctl;
885 struct list_head bitmap_list;
886 struct btrfs_key key;
887 u64 start, extent_start, extent_end, len;
888 int entries = 0;
889 int bitmaps = 0;
890 int ret;
891 int err = -1;
892
893 INIT_LIST_HEAD(&bitmap_list);
894
895 if (!i_size_read(inode))
896 return -1;
897
898 ret = io_ctl_init(&io_ctl, inode, root);
899 if (ret)
900 return -1;
901
902 /* Get the cluster for this block_group if it exists */
903 if (block_group && !list_empty(&block_group->cluster_list))
904 cluster = list_entry(block_group->cluster_list.next,
905 struct btrfs_free_cluster,
906 block_group_list);
907
908 /* Lock all pages first so we can lock the extent safely. */
909 io_ctl_prepare_pages(&io_ctl, inode, 0);
910
911 lock_extent_bits(&BTRFS_I(inode)->io_tree, 0, i_size_read(inode) - 1,
912 0, &cached_state);
913
914 node = rb_first(&ctl->free_space_offset);
915 if (!node && cluster) {
916 node = rb_first(&cluster->root);
917 cluster = NULL;
918 }
919
920 /* Make sure we can fit our crcs into the first page */
921 if (io_ctl.check_crcs &&
922 (io_ctl.num_pages * sizeof(u32)) >= PAGE_CACHE_SIZE)
923 goto out_nospc;
924
925 io_ctl_set_generation(&io_ctl, trans->transid);
926
927 /* Write out the extent entries */
928 while (node) {
929 struct btrfs_free_space *e;
930
931 e = rb_entry(node, struct btrfs_free_space, offset_index);
932 entries++;
933
934 ret = io_ctl_add_entry(&io_ctl, e->offset, e->bytes,
935 e->bitmap);
936 if (ret)
937 goto out_nospc;
938
939 if (e->bitmap) {
940 list_add_tail(&e->list, &bitmap_list);
941 bitmaps++;
942 }
943 node = rb_next(node);
944 if (!node && cluster) {
945 node = rb_first(&cluster->root);
946 cluster = NULL;
947 }
948 }
949
950 /*
951 * We want to add any pinned extents to our free space cache
952 * so we don't leak the space
953 */
954
955 /*
956 * We shouldn't have switched the pinned extents yet so this is the
957 * right one
958 */
959 unpin = root->fs_info->pinned_extents;
960
961 if (block_group)
962 start = block_group->key.objectid;
963
964 while (block_group && (start < block_group->key.objectid +
965 block_group->key.offset)) {
966 ret = find_first_extent_bit(unpin, start,
967 &extent_start, &extent_end,
968 EXTENT_DIRTY, NULL);
969 if (ret) {
970 ret = 0;
971 break;
972 }
973
974 /* This pinned extent is out of our range */
975 if (extent_start >= block_group->key.objectid +
976 block_group->key.offset)
977 break;
978
979 extent_start = max(extent_start, start);
980 extent_end = min(block_group->key.objectid +
981 block_group->key.offset, extent_end + 1);
982 len = extent_end - extent_start;
983
984 entries++;
985 ret = io_ctl_add_entry(&io_ctl, extent_start, len, NULL);
986 if (ret)
987 goto out_nospc;
988
989 start = extent_end;
990 }
991
992 /* Write out the bitmaps */
993 list_for_each_safe(pos, n, &bitmap_list) {
994 struct btrfs_free_space *entry =
995 list_entry(pos, struct btrfs_free_space, list);
996
997 ret = io_ctl_add_bitmap(&io_ctl, entry->bitmap);
998 if (ret)
999 goto out_nospc;
1000 list_del_init(&entry->list);
1001 }
1002
1003 /* Zero out the rest of the pages just to make sure */
1004 io_ctl_zero_remaining_pages(&io_ctl);
1005
1006 ret = btrfs_dirty_pages(root, inode, io_ctl.pages, io_ctl.num_pages,
1007 0, i_size_read(inode), &cached_state);
1008 io_ctl_drop_pages(&io_ctl);
1009 unlock_extent_cached(&BTRFS_I(inode)->io_tree, 0,
1010 i_size_read(inode) - 1, &cached_state, GFP_NOFS);
1011
1012 if (ret)
1013 goto out;
1014
1015
1016 btrfs_wait_ordered_range(inode, 0, (u64)-1);
1017
1018 key.objectid = BTRFS_FREE_SPACE_OBJECTID;
1019 key.offset = offset;
1020 key.type = 0;
1021
1022 ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
1023 if (ret < 0) {
1024 clear_extent_bit(&BTRFS_I(inode)->io_tree, 0, inode->i_size - 1,
1025 EXTENT_DIRTY | EXTENT_DELALLOC, 0, 0, NULL,
1026 GFP_NOFS);
1027 goto out;
1028 }
1029 leaf = path->nodes[0];
1030 if (ret > 0) {
1031 struct btrfs_key found_key;
1032 BUG_ON(!path->slots[0]);
1033 path->slots[0]--;
1034 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
1035 if (found_key.objectid != BTRFS_FREE_SPACE_OBJECTID ||
1036 found_key.offset != offset) {
1037 clear_extent_bit(&BTRFS_I(inode)->io_tree, 0,
1038 inode->i_size - 1,
1039 EXTENT_DIRTY | EXTENT_DELALLOC, 0, 0,
1040 NULL, GFP_NOFS);
1041 btrfs_release_path(path);
1042 goto out;
1043 }
1044 }
1045
1046 BTRFS_I(inode)->generation = trans->transid;
1047 header = btrfs_item_ptr(leaf, path->slots[0],
1048 struct btrfs_free_space_header);
1049 btrfs_set_free_space_entries(leaf, header, entries);
1050 btrfs_set_free_space_bitmaps(leaf, header, bitmaps);
1051 btrfs_set_free_space_generation(leaf, header, trans->transid);
1052 btrfs_mark_buffer_dirty(leaf);
1053 btrfs_release_path(path);
1054
1055 err = 0;
1056 out:
1057 io_ctl_free(&io_ctl);
1058 if (err) {
1059 invalidate_inode_pages2(inode->i_mapping);
1060 BTRFS_I(inode)->generation = 0;
1061 }
1062 btrfs_update_inode(trans, root, inode);
1063 return err;
1064
1065 out_nospc:
1066 list_for_each_safe(pos, n, &bitmap_list) {
1067 struct btrfs_free_space *entry =
1068 list_entry(pos, struct btrfs_free_space, list);
1069 list_del_init(&entry->list);
1070 }
1071 io_ctl_drop_pages(&io_ctl);
1072 unlock_extent_cached(&BTRFS_I(inode)->io_tree, 0,
1073 i_size_read(inode) - 1, &cached_state, GFP_NOFS);
1074 goto out;
1075 }
1076
1077 int btrfs_write_out_cache(struct btrfs_root *root,
1078 struct btrfs_trans_handle *trans,
1079 struct btrfs_block_group_cache *block_group,
1080 struct btrfs_path *path)
1081 {
1082 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
1083 struct inode *inode;
1084 int ret = 0;
1085
1086 root = root->fs_info->tree_root;
1087
1088 spin_lock(&block_group->lock);
1089 if (block_group->disk_cache_state < BTRFS_DC_SETUP) {
1090 spin_unlock(&block_group->lock);
1091 return 0;
1092 }
1093 spin_unlock(&block_group->lock);
1094
1095 inode = lookup_free_space_inode(root, block_group, path);
1096 if (IS_ERR(inode))
1097 return 0;
1098
1099 ret = __btrfs_write_out_cache(root, inode, ctl, block_group, trans,
1100 path, block_group->key.objectid);
1101 if (ret) {
1102 spin_lock(&block_group->lock);
1103 block_group->disk_cache_state = BTRFS_DC_ERROR;
1104 spin_unlock(&block_group->lock);
1105 ret = 0;
1106 #ifdef DEBUG
1107 btrfs_err(root->fs_info,
1108 "failed to write free space cache for block group %llu",
1109 block_group->key.objectid);
1110 #endif
1111 }
1112
1113 iput(inode);
1114 return ret;
1115 }
1116
1117 static inline unsigned long offset_to_bit(u64 bitmap_start, u32 unit,
1118 u64 offset)
1119 {
1120 BUG_ON(offset < bitmap_start);
1121 offset -= bitmap_start;
1122 return (unsigned long)(div_u64(offset, unit));
1123 }
1124
1125 static inline unsigned long bytes_to_bits(u64 bytes, u32 unit)
1126 {
1127 return (unsigned long)(div_u64(bytes, unit));
1128 }
1129
1130 static inline u64 offset_to_bitmap(struct btrfs_free_space_ctl *ctl,
1131 u64 offset)
1132 {
1133 u64 bitmap_start;
1134 u64 bytes_per_bitmap;
1135
1136 bytes_per_bitmap = BITS_PER_BITMAP * ctl->unit;
1137 bitmap_start = offset - ctl->start;
1138 bitmap_start = div64_u64(bitmap_start, bytes_per_bitmap);
1139 bitmap_start *= bytes_per_bitmap;
1140 bitmap_start += ctl->start;
1141
1142 return bitmap_start;
1143 }
1144
1145 static int tree_insert_offset(struct rb_root *root, u64 offset,
1146 struct rb_node *node, int bitmap)
1147 {
1148 struct rb_node **p = &root->rb_node;
1149 struct rb_node *parent = NULL;
1150 struct btrfs_free_space *info;
1151
1152 while (*p) {
1153 parent = *p;
1154 info = rb_entry(parent, struct btrfs_free_space, offset_index);
1155
1156 if (offset < info->offset) {
1157 p = &(*p)->rb_left;
1158 } else if (offset > info->offset) {
1159 p = &(*p)->rb_right;
1160 } else {
1161 /*
1162 * we could have a bitmap entry and an extent entry
1163 * share the same offset. If this is the case, we want
1164 * the extent entry to always be found first if we do a
1165 * linear search through the tree, since we want to have
1166 * the quickest allocation time, and allocating from an
1167 * extent is faster than allocating from a bitmap. So
1168 * if we're inserting a bitmap and we find an entry at
1169 * this offset, we want to go right, or after this entry
1170 * logically. If we are inserting an extent and we've
1171 * found a bitmap, we want to go left, or before
1172 * logically.
1173 */
1174 if (bitmap) {
1175 if (info->bitmap) {
1176 WARN_ON_ONCE(1);
1177 return -EEXIST;
1178 }
1179 p = &(*p)->rb_right;
1180 } else {
1181 if (!info->bitmap) {
1182 WARN_ON_ONCE(1);
1183 return -EEXIST;
1184 }
1185 p = &(*p)->rb_left;
1186 }
1187 }
1188 }
1189
1190 rb_link_node(node, parent, p);
1191 rb_insert_color(node, root);
1192
1193 return 0;
1194 }
1195
1196 /*
1197 * searches the tree for the given offset.
1198 *
1199 * fuzzy - If this is set, then we are trying to make an allocation, and we just
1200 * want a section that has at least bytes size and comes at or after the given
1201 * offset.
1202 */
1203 static struct btrfs_free_space *
1204 tree_search_offset(struct btrfs_free_space_ctl *ctl,
1205 u64 offset, int bitmap_only, int fuzzy)
1206 {
1207 struct rb_node *n = ctl->free_space_offset.rb_node;
1208 struct btrfs_free_space *entry, *prev = NULL;
1209
1210 /* find entry that is closest to the 'offset' */
1211 while (1) {
1212 if (!n) {
1213 entry = NULL;
1214 break;
1215 }
1216
1217 entry = rb_entry(n, struct btrfs_free_space, offset_index);
1218 prev = entry;
1219
1220 if (offset < entry->offset)
1221 n = n->rb_left;
1222 else if (offset > entry->offset)
1223 n = n->rb_right;
1224 else
1225 break;
1226 }
1227
1228 if (bitmap_only) {
1229 if (!entry)
1230 return NULL;
1231 if (entry->bitmap)
1232 return entry;
1233
1234 /*
1235 * bitmap entry and extent entry may share same offset,
1236 * in that case, bitmap entry comes after extent entry.
1237 */
1238 n = rb_next(n);
1239 if (!n)
1240 return NULL;
1241 entry = rb_entry(n, struct btrfs_free_space, offset_index);
1242 if (entry->offset != offset)
1243 return NULL;
1244
1245 WARN_ON(!entry->bitmap);
1246 return entry;
1247 } else if (entry) {
1248 if (entry->bitmap) {
1249 /*
1250 * if previous extent entry covers the offset,
1251 * we should return it instead of the bitmap entry
1252 */
1253 n = rb_prev(&entry->offset_index);
1254 if (n) {
1255 prev = rb_entry(n, struct btrfs_free_space,
1256 offset_index);
1257 if (!prev->bitmap &&
1258 prev->offset + prev->bytes > offset)
1259 entry = prev;
1260 }
1261 }
1262 return entry;
1263 }
1264
1265 if (!prev)
1266 return NULL;
1267
1268 /* find last entry before the 'offset' */
1269 entry = prev;
1270 if (entry->offset > offset) {
1271 n = rb_prev(&entry->offset_index);
1272 if (n) {
1273 entry = rb_entry(n, struct btrfs_free_space,
1274 offset_index);
1275 BUG_ON(entry->offset > offset);
1276 } else {
1277 if (fuzzy)
1278 return entry;
1279 else
1280 return NULL;
1281 }
1282 }
1283
1284 if (entry->bitmap) {
1285 n = rb_prev(&entry->offset_index);
1286 if (n) {
1287 prev = rb_entry(n, struct btrfs_free_space,
1288 offset_index);
1289 if (!prev->bitmap &&
1290 prev->offset + prev->bytes > offset)
1291 return prev;
1292 }
1293 if (entry->offset + BITS_PER_BITMAP * ctl->unit > offset)
1294 return entry;
1295 } else if (entry->offset + entry->bytes > offset)
1296 return entry;
1297
1298 if (!fuzzy)
1299 return NULL;
1300
1301 while (1) {
1302 if (entry->bitmap) {
1303 if (entry->offset + BITS_PER_BITMAP *
1304 ctl->unit > offset)
1305 break;
1306 } else {
1307 if (entry->offset + entry->bytes > offset)
1308 break;
1309 }
1310
1311 n = rb_next(&entry->offset_index);
1312 if (!n)
1313 return NULL;
1314 entry = rb_entry(n, struct btrfs_free_space, offset_index);
1315 }
1316 return entry;
1317 }
1318
1319 static inline void
1320 __unlink_free_space(struct btrfs_free_space_ctl *ctl,
1321 struct btrfs_free_space *info)
1322 {
1323 rb_erase(&info->offset_index, &ctl->free_space_offset);
1324 ctl->free_extents--;
1325 }
1326
1327 static void unlink_free_space(struct btrfs_free_space_ctl *ctl,
1328 struct btrfs_free_space *info)
1329 {
1330 __unlink_free_space(ctl, info);
1331 ctl->free_space -= info->bytes;
1332 }
1333
1334 static int link_free_space(struct btrfs_free_space_ctl *ctl,
1335 struct btrfs_free_space *info)
1336 {
1337 int ret = 0;
1338
1339 BUG_ON(!info->bitmap && !info->bytes);
1340 ret = tree_insert_offset(&ctl->free_space_offset, info->offset,
1341 &info->offset_index, (info->bitmap != NULL));
1342 if (ret)
1343 return ret;
1344
1345 ctl->free_space += info->bytes;
1346 ctl->free_extents++;
1347 return ret;
1348 }
1349
1350 static void recalculate_thresholds(struct btrfs_free_space_ctl *ctl)
1351 {
1352 struct btrfs_block_group_cache *block_group = ctl->private;
1353 u64 max_bytes;
1354 u64 bitmap_bytes;
1355 u64 extent_bytes;
1356 u64 size = block_group->key.offset;
1357 u64 bytes_per_bg = BITS_PER_BITMAP * ctl->unit;
1358 int max_bitmaps = div64_u64(size + bytes_per_bg - 1, bytes_per_bg);
1359
1360 max_bitmaps = max(max_bitmaps, 1);
1361
1362 BUG_ON(ctl->total_bitmaps > max_bitmaps);
1363
1364 /*
1365 * The goal is to keep the total amount of memory used per 1gb of space
1366 * at or below 32k, so we need to adjust how much memory we allow to be
1367 * used by extent based free space tracking
1368 */
1369 if (size < 1024 * 1024 * 1024)
1370 max_bytes = MAX_CACHE_BYTES_PER_GIG;
1371 else
1372 max_bytes = MAX_CACHE_BYTES_PER_GIG *
1373 div64_u64(size, 1024 * 1024 * 1024);
1374
1375 /*
1376 * we want to account for 1 more bitmap than what we have so we can make
1377 * sure we don't go over our overall goal of MAX_CACHE_BYTES_PER_GIG as
1378 * we add more bitmaps.
1379 */
1380 bitmap_bytes = (ctl->total_bitmaps + 1) * PAGE_CACHE_SIZE;
1381
1382 if (bitmap_bytes >= max_bytes) {
1383 ctl->extents_thresh = 0;
1384 return;
1385 }
1386
1387 /*
1388 * we want the extent entry threshold to always be at most 1/2 the maxw
1389 * bytes we can have, or whatever is less than that.
1390 */
1391 extent_bytes = max_bytes - bitmap_bytes;
1392 extent_bytes = min_t(u64, extent_bytes, div64_u64(max_bytes, 2));
1393
1394 ctl->extents_thresh =
1395 div64_u64(extent_bytes, (sizeof(struct btrfs_free_space)));
1396 }
1397
1398 static inline void __bitmap_clear_bits(struct btrfs_free_space_ctl *ctl,
1399 struct btrfs_free_space *info,
1400 u64 offset, u64 bytes)
1401 {
1402 unsigned long start, count;
1403
1404 start = offset_to_bit(info->offset, ctl->unit, offset);
1405 count = bytes_to_bits(bytes, ctl->unit);
1406 BUG_ON(start + count > BITS_PER_BITMAP);
1407
1408 bitmap_clear(info->bitmap, start, count);
1409
1410 info->bytes -= bytes;
1411 }
1412
1413 static void bitmap_clear_bits(struct btrfs_free_space_ctl *ctl,
1414 struct btrfs_free_space *info, u64 offset,
1415 u64 bytes)
1416 {
1417 __bitmap_clear_bits(ctl, info, offset, bytes);
1418 ctl->free_space -= bytes;
1419 }
1420
1421 static void bitmap_set_bits(struct btrfs_free_space_ctl *ctl,
1422 struct btrfs_free_space *info, u64 offset,
1423 u64 bytes)
1424 {
1425 unsigned long start, count;
1426
1427 start = offset_to_bit(info->offset, ctl->unit, offset);
1428 count = bytes_to_bits(bytes, ctl->unit);
1429 BUG_ON(start + count > BITS_PER_BITMAP);
1430
1431 bitmap_set(info->bitmap, start, count);
1432
1433 info->bytes += bytes;
1434 ctl->free_space += bytes;
1435 }
1436
1437 static int search_bitmap(struct btrfs_free_space_ctl *ctl,
1438 struct btrfs_free_space *bitmap_info, u64 *offset,
1439 u64 *bytes)
1440 {
1441 unsigned long found_bits = 0;
1442 unsigned long bits, i;
1443 unsigned long next_zero;
1444
1445 i = offset_to_bit(bitmap_info->offset, ctl->unit,
1446 max_t(u64, *offset, bitmap_info->offset));
1447 bits = bytes_to_bits(*bytes, ctl->unit);
1448
1449 for_each_set_bit_from(i, bitmap_info->bitmap, BITS_PER_BITMAP) {
1450 next_zero = find_next_zero_bit(bitmap_info->bitmap,
1451 BITS_PER_BITMAP, i);
1452 if ((next_zero - i) >= bits) {
1453 found_bits = next_zero - i;
1454 break;
1455 }
1456 i = next_zero;
1457 }
1458
1459 if (found_bits) {
1460 *offset = (u64)(i * ctl->unit) + bitmap_info->offset;
1461 *bytes = (u64)(found_bits) * ctl->unit;
1462 return 0;
1463 }
1464
1465 return -1;
1466 }
1467
1468 static struct btrfs_free_space *
1469 find_free_space(struct btrfs_free_space_ctl *ctl, u64 *offset, u64 *bytes,
1470 unsigned long align)
1471 {
1472 struct btrfs_free_space *entry;
1473 struct rb_node *node;
1474 u64 ctl_off;
1475 u64 tmp;
1476 u64 align_off;
1477 int ret;
1478
1479 if (!ctl->free_space_offset.rb_node)
1480 return NULL;
1481
1482 entry = tree_search_offset(ctl, offset_to_bitmap(ctl, *offset), 0, 1);
1483 if (!entry)
1484 return NULL;
1485
1486 for (node = &entry->offset_index; node; node = rb_next(node)) {
1487 entry = rb_entry(node, struct btrfs_free_space, offset_index);
1488 if (entry->bytes < *bytes)
1489 continue;
1490
1491 /* make sure the space returned is big enough
1492 * to match our requested alignment
1493 */
1494 if (*bytes >= align) {
1495 ctl_off = entry->offset - ctl->start;
1496 tmp = ctl_off + align - 1;;
1497 do_div(tmp, align);
1498 tmp = tmp * align + ctl->start;
1499 align_off = tmp - entry->offset;
1500 } else {
1501 align_off = 0;
1502 tmp = entry->offset;
1503 }
1504
1505 if (entry->bytes < *bytes + align_off)
1506 continue;
1507
1508 if (entry->bitmap) {
1509 ret = search_bitmap(ctl, entry, &tmp, bytes);
1510 if (!ret) {
1511 *offset = tmp;
1512 return entry;
1513 }
1514 continue;
1515 }
1516
1517 *offset = tmp;
1518 *bytes = entry->bytes - align_off;
1519 return entry;
1520 }
1521
1522 return NULL;
1523 }
1524
1525 static void add_new_bitmap(struct btrfs_free_space_ctl *ctl,
1526 struct btrfs_free_space *info, u64 offset)
1527 {
1528 info->offset = offset_to_bitmap(ctl, offset);
1529 info->bytes = 0;
1530 INIT_LIST_HEAD(&info->list);
1531 link_free_space(ctl, info);
1532 ctl->total_bitmaps++;
1533
1534 ctl->op->recalc_thresholds(ctl);
1535 }
1536
1537 static void free_bitmap(struct btrfs_free_space_ctl *ctl,
1538 struct btrfs_free_space *bitmap_info)
1539 {
1540 unlink_free_space(ctl, bitmap_info);
1541 kfree(bitmap_info->bitmap);
1542 kmem_cache_free(btrfs_free_space_cachep, bitmap_info);
1543 ctl->total_bitmaps--;
1544 ctl->op->recalc_thresholds(ctl);
1545 }
1546
1547 static noinline int remove_from_bitmap(struct btrfs_free_space_ctl *ctl,
1548 struct btrfs_free_space *bitmap_info,
1549 u64 *offset, u64 *bytes)
1550 {
1551 u64 end;
1552 u64 search_start, search_bytes;
1553 int ret;
1554
1555 again:
1556 end = bitmap_info->offset + (u64)(BITS_PER_BITMAP * ctl->unit) - 1;
1557
1558 /*
1559 * We need to search for bits in this bitmap. We could only cover some
1560 * of the extent in this bitmap thanks to how we add space, so we need
1561 * to search for as much as it as we can and clear that amount, and then
1562 * go searching for the next bit.
1563 */
1564 search_start = *offset;
1565 search_bytes = ctl->unit;
1566 search_bytes = min(search_bytes, end - search_start + 1);
1567 ret = search_bitmap(ctl, bitmap_info, &search_start, &search_bytes);
1568 if (ret < 0 || search_start != *offset)
1569 return -EINVAL;
1570
1571 /* We may have found more bits than what we need */
1572 search_bytes = min(search_bytes, *bytes);
1573
1574 /* Cannot clear past the end of the bitmap */
1575 search_bytes = min(search_bytes, end - search_start + 1);
1576
1577 bitmap_clear_bits(ctl, bitmap_info, search_start, search_bytes);
1578 *offset += search_bytes;
1579 *bytes -= search_bytes;
1580
1581 if (*bytes) {
1582 struct rb_node *next = rb_next(&bitmap_info->offset_index);
1583 if (!bitmap_info->bytes)
1584 free_bitmap(ctl, bitmap_info);
1585
1586 /*
1587 * no entry after this bitmap, but we still have bytes to
1588 * remove, so something has gone wrong.
1589 */
1590 if (!next)
1591 return -EINVAL;
1592
1593 bitmap_info = rb_entry(next, struct btrfs_free_space,
1594 offset_index);
1595
1596 /*
1597 * if the next entry isn't a bitmap we need to return to let the
1598 * extent stuff do its work.
1599 */
1600 if (!bitmap_info->bitmap)
1601 return -EAGAIN;
1602
1603 /*
1604 * Ok the next item is a bitmap, but it may not actually hold
1605 * the information for the rest of this free space stuff, so
1606 * look for it, and if we don't find it return so we can try
1607 * everything over again.
1608 */
1609 search_start = *offset;
1610 search_bytes = ctl->unit;
1611 ret = search_bitmap(ctl, bitmap_info, &search_start,
1612 &search_bytes);
1613 if (ret < 0 || search_start != *offset)
1614 return -EAGAIN;
1615
1616 goto again;
1617 } else if (!bitmap_info->bytes)
1618 free_bitmap(ctl, bitmap_info);
1619
1620 return 0;
1621 }
1622
1623 static u64 add_bytes_to_bitmap(struct btrfs_free_space_ctl *ctl,
1624 struct btrfs_free_space *info, u64 offset,
1625 u64 bytes)
1626 {
1627 u64 bytes_to_set = 0;
1628 u64 end;
1629
1630 end = info->offset + (u64)(BITS_PER_BITMAP * ctl->unit);
1631
1632 bytes_to_set = min(end - offset, bytes);
1633
1634 bitmap_set_bits(ctl, info, offset, bytes_to_set);
1635
1636 return bytes_to_set;
1637
1638 }
1639
1640 static bool use_bitmap(struct btrfs_free_space_ctl *ctl,
1641 struct btrfs_free_space *info)
1642 {
1643 struct btrfs_block_group_cache *block_group = ctl->private;
1644
1645 /*
1646 * If we are below the extents threshold then we can add this as an
1647 * extent, and don't have to deal with the bitmap
1648 */
1649 if (ctl->free_extents < ctl->extents_thresh) {
1650 /*
1651 * If this block group has some small extents we don't want to
1652 * use up all of our free slots in the cache with them, we want
1653 * to reserve them to larger extents, however if we have plent
1654 * of cache left then go ahead an dadd them, no sense in adding
1655 * the overhead of a bitmap if we don't have to.
1656 */
1657 if (info->bytes <= block_group->sectorsize * 4) {
1658 if (ctl->free_extents * 2 <= ctl->extents_thresh)
1659 return false;
1660 } else {
1661 return false;
1662 }
1663 }
1664
1665 /*
1666 * The original block groups from mkfs can be really small, like 8
1667 * megabytes, so don't bother with a bitmap for those entries. However
1668 * some block groups can be smaller than what a bitmap would cover but
1669 * are still large enough that they could overflow the 32k memory limit,
1670 * so allow those block groups to still be allowed to have a bitmap
1671 * entry.
1672 */
1673 if (((BITS_PER_BITMAP * ctl->unit) >> 1) > block_group->key.offset)
1674 return false;
1675
1676 return true;
1677 }
1678
1679 static struct btrfs_free_space_op free_space_op = {
1680 .recalc_thresholds = recalculate_thresholds,
1681 .use_bitmap = use_bitmap,
1682 };
1683
1684 static int insert_into_bitmap(struct btrfs_free_space_ctl *ctl,
1685 struct btrfs_free_space *info)
1686 {
1687 struct btrfs_free_space *bitmap_info;
1688 struct btrfs_block_group_cache *block_group = NULL;
1689 int added = 0;
1690 u64 bytes, offset, bytes_added;
1691 int ret;
1692
1693 bytes = info->bytes;
1694 offset = info->offset;
1695
1696 if (!ctl->op->use_bitmap(ctl, info))
1697 return 0;
1698
1699 if (ctl->op == &free_space_op)
1700 block_group = ctl->private;
1701 again:
1702 /*
1703 * Since we link bitmaps right into the cluster we need to see if we
1704 * have a cluster here, and if so and it has our bitmap we need to add
1705 * the free space to that bitmap.
1706 */
1707 if (block_group && !list_empty(&block_group->cluster_list)) {
1708 struct btrfs_free_cluster *cluster;
1709 struct rb_node *node;
1710 struct btrfs_free_space *entry;
1711
1712 cluster = list_entry(block_group->cluster_list.next,
1713 struct btrfs_free_cluster,
1714 block_group_list);
1715 spin_lock(&cluster->lock);
1716 node = rb_first(&cluster->root);
1717 if (!node) {
1718 spin_unlock(&cluster->lock);
1719 goto no_cluster_bitmap;
1720 }
1721
1722 entry = rb_entry(node, struct btrfs_free_space, offset_index);
1723 if (!entry->bitmap) {
1724 spin_unlock(&cluster->lock);
1725 goto no_cluster_bitmap;
1726 }
1727
1728 if (entry->offset == offset_to_bitmap(ctl, offset)) {
1729 bytes_added = add_bytes_to_bitmap(ctl, entry,
1730 offset, bytes);
1731 bytes -= bytes_added;
1732 offset += bytes_added;
1733 }
1734 spin_unlock(&cluster->lock);
1735 if (!bytes) {
1736 ret = 1;
1737 goto out;
1738 }
1739 }
1740
1741 no_cluster_bitmap:
1742 bitmap_info = tree_search_offset(ctl, offset_to_bitmap(ctl, offset),
1743 1, 0);
1744 if (!bitmap_info) {
1745 BUG_ON(added);
1746 goto new_bitmap;
1747 }
1748
1749 bytes_added = add_bytes_to_bitmap(ctl, bitmap_info, offset, bytes);
1750 bytes -= bytes_added;
1751 offset += bytes_added;
1752 added = 0;
1753
1754 if (!bytes) {
1755 ret = 1;
1756 goto out;
1757 } else
1758 goto again;
1759
1760 new_bitmap:
1761 if (info && info->bitmap) {
1762 add_new_bitmap(ctl, info, offset);
1763 added = 1;
1764 info = NULL;
1765 goto again;
1766 } else {
1767 spin_unlock(&ctl->tree_lock);
1768
1769 /* no pre-allocated info, allocate a new one */
1770 if (!info) {
1771 info = kmem_cache_zalloc(btrfs_free_space_cachep,
1772 GFP_NOFS);
1773 if (!info) {
1774 spin_lock(&ctl->tree_lock);
1775 ret = -ENOMEM;
1776 goto out;
1777 }
1778 }
1779
1780 /* allocate the bitmap */
1781 info->bitmap = kzalloc(PAGE_CACHE_SIZE, GFP_NOFS);
1782 spin_lock(&ctl->tree_lock);
1783 if (!info->bitmap) {
1784 ret = -ENOMEM;
1785 goto out;
1786 }
1787 goto again;
1788 }
1789
1790 out:
1791 if (info) {
1792 if (info->bitmap)
1793 kfree(info->bitmap);
1794 kmem_cache_free(btrfs_free_space_cachep, info);
1795 }
1796
1797 return ret;
1798 }
1799
1800 static bool try_merge_free_space(struct btrfs_free_space_ctl *ctl,
1801 struct btrfs_free_space *info, bool update_stat)
1802 {
1803 struct btrfs_free_space *left_info;
1804 struct btrfs_free_space *right_info;
1805 bool merged = false;
1806 u64 offset = info->offset;
1807 u64 bytes = info->bytes;
1808
1809 /*
1810 * first we want to see if there is free space adjacent to the range we
1811 * are adding, if there is remove that struct and add a new one to
1812 * cover the entire range
1813 */
1814 right_info = tree_search_offset(ctl, offset + bytes, 0, 0);
1815 if (right_info && rb_prev(&right_info->offset_index))
1816 left_info = rb_entry(rb_prev(&right_info->offset_index),
1817 struct btrfs_free_space, offset_index);
1818 else
1819 left_info = tree_search_offset(ctl, offset - 1, 0, 0);
1820
1821 if (right_info && !right_info->bitmap) {
1822 if (update_stat)
1823 unlink_free_space(ctl, right_info);
1824 else
1825 __unlink_free_space(ctl, right_info);
1826 info->bytes += right_info->bytes;
1827 kmem_cache_free(btrfs_free_space_cachep, right_info);
1828 merged = true;
1829 }
1830
1831 if (left_info && !left_info->bitmap &&
1832 left_info->offset + left_info->bytes == offset) {
1833 if (update_stat)
1834 unlink_free_space(ctl, left_info);
1835 else
1836 __unlink_free_space(ctl, left_info);
1837 info->offset = left_info->offset;
1838 info->bytes += left_info->bytes;
1839 kmem_cache_free(btrfs_free_space_cachep, left_info);
1840 merged = true;
1841 }
1842
1843 return merged;
1844 }
1845
1846 int __btrfs_add_free_space(struct btrfs_free_space_ctl *ctl,
1847 u64 offset, u64 bytes)
1848 {
1849 struct btrfs_free_space *info;
1850 int ret = 0;
1851
1852 info = kmem_cache_zalloc(btrfs_free_space_cachep, GFP_NOFS);
1853 if (!info)
1854 return -ENOMEM;
1855
1856 info->offset = offset;
1857 info->bytes = bytes;
1858
1859 spin_lock(&ctl->tree_lock);
1860
1861 if (try_merge_free_space(ctl, info, true))
1862 goto link;
1863
1864 /*
1865 * There was no extent directly to the left or right of this new
1866 * extent then we know we're going to have to allocate a new extent, so
1867 * before we do that see if we need to drop this into a bitmap
1868 */
1869 ret = insert_into_bitmap(ctl, info);
1870 if (ret < 0) {
1871 goto out;
1872 } else if (ret) {
1873 ret = 0;
1874 goto out;
1875 }
1876 link:
1877 ret = link_free_space(ctl, info);
1878 if (ret)
1879 kmem_cache_free(btrfs_free_space_cachep, info);
1880 out:
1881 spin_unlock(&ctl->tree_lock);
1882
1883 if (ret) {
1884 printk(KERN_CRIT "btrfs: unable to add free space :%d\n", ret);
1885 BUG_ON(ret == -EEXIST);
1886 }
1887
1888 return ret;
1889 }
1890
1891 int btrfs_remove_free_space(struct btrfs_block_group_cache *block_group,
1892 u64 offset, u64 bytes)
1893 {
1894 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
1895 struct btrfs_free_space *info;
1896 int ret;
1897 bool re_search = false;
1898
1899 spin_lock(&ctl->tree_lock);
1900
1901 again:
1902 ret = 0;
1903 if (!bytes)
1904 goto out_lock;
1905
1906 info = tree_search_offset(ctl, offset, 0, 0);
1907 if (!info) {
1908 /*
1909 * oops didn't find an extent that matched the space we wanted
1910 * to remove, look for a bitmap instead
1911 */
1912 info = tree_search_offset(ctl, offset_to_bitmap(ctl, offset),
1913 1, 0);
1914 if (!info) {
1915 /*
1916 * If we found a partial bit of our free space in a
1917 * bitmap but then couldn't find the other part this may
1918 * be a problem, so WARN about it.
1919 */
1920 WARN_ON(re_search);
1921 goto out_lock;
1922 }
1923 }
1924
1925 re_search = false;
1926 if (!info->bitmap) {
1927 unlink_free_space(ctl, info);
1928 if (offset == info->offset) {
1929 u64 to_free = min(bytes, info->bytes);
1930
1931 info->bytes -= to_free;
1932 info->offset += to_free;
1933 if (info->bytes) {
1934 ret = link_free_space(ctl, info);
1935 WARN_ON(ret);
1936 } else {
1937 kmem_cache_free(btrfs_free_space_cachep, info);
1938 }
1939
1940 offset += to_free;
1941 bytes -= to_free;
1942 goto again;
1943 } else {
1944 u64 old_end = info->bytes + info->offset;
1945
1946 info->bytes = offset - info->offset;
1947 ret = link_free_space(ctl, info);
1948 WARN_ON(ret);
1949 if (ret)
1950 goto out_lock;
1951
1952 /* Not enough bytes in this entry to satisfy us */
1953 if (old_end < offset + bytes) {
1954 bytes -= old_end - offset;
1955 offset = old_end;
1956 goto again;
1957 } else if (old_end == offset + bytes) {
1958 /* all done */
1959 goto out_lock;
1960 }
1961 spin_unlock(&ctl->tree_lock);
1962
1963 ret = btrfs_add_free_space(block_group, offset + bytes,
1964 old_end - (offset + bytes));
1965 WARN_ON(ret);
1966 goto out;
1967 }
1968 }
1969
1970 ret = remove_from_bitmap(ctl, info, &offset, &bytes);
1971 if (ret == -EAGAIN) {
1972 re_search = true;
1973 goto again;
1974 }
1975 out_lock:
1976 spin_unlock(&ctl->tree_lock);
1977 out:
1978 return ret;
1979 }
1980
1981 void btrfs_dump_free_space(struct btrfs_block_group_cache *block_group,
1982 u64 bytes)
1983 {
1984 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
1985 struct btrfs_free_space *info;
1986 struct rb_node *n;
1987 int count = 0;
1988
1989 for (n = rb_first(&ctl->free_space_offset); n; n = rb_next(n)) {
1990 info = rb_entry(n, struct btrfs_free_space, offset_index);
1991 if (info->bytes >= bytes && !block_group->ro)
1992 count++;
1993 printk(KERN_CRIT "entry offset %llu, bytes %llu, bitmap %s\n",
1994 (unsigned long long)info->offset,
1995 (unsigned long long)info->bytes,
1996 (info->bitmap) ? "yes" : "no");
1997 }
1998 printk(KERN_INFO "block group has cluster?: %s\n",
1999 list_empty(&block_group->cluster_list) ? "no" : "yes");
2000 printk(KERN_INFO "%d blocks of free space at or bigger than bytes is"
2001 "\n", count);
2002 }
2003
2004 void btrfs_init_free_space_ctl(struct btrfs_block_group_cache *block_group)
2005 {
2006 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2007
2008 spin_lock_init(&ctl->tree_lock);
2009 ctl->unit = block_group->sectorsize;
2010 ctl->start = block_group->key.objectid;
2011 ctl->private = block_group;
2012 ctl->op = &free_space_op;
2013
2014 /*
2015 * we only want to have 32k of ram per block group for keeping
2016 * track of free space, and if we pass 1/2 of that we want to
2017 * start converting things over to using bitmaps
2018 */
2019 ctl->extents_thresh = ((1024 * 32) / 2) /
2020 sizeof(struct btrfs_free_space);
2021 }
2022
2023 /*
2024 * for a given cluster, put all of its extents back into the free
2025 * space cache. If the block group passed doesn't match the block group
2026 * pointed to by the cluster, someone else raced in and freed the
2027 * cluster already. In that case, we just return without changing anything
2028 */
2029 static int
2030 __btrfs_return_cluster_to_free_space(
2031 struct btrfs_block_group_cache *block_group,
2032 struct btrfs_free_cluster *cluster)
2033 {
2034 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2035 struct btrfs_free_space *entry;
2036 struct rb_node *node;
2037
2038 spin_lock(&cluster->lock);
2039 if (cluster->block_group != block_group)
2040 goto out;
2041
2042 cluster->block_group = NULL;
2043 cluster->window_start = 0;
2044 list_del_init(&cluster->block_group_list);
2045
2046 node = rb_first(&cluster->root);
2047 while (node) {
2048 bool bitmap;
2049
2050 entry = rb_entry(node, struct btrfs_free_space, offset_index);
2051 node = rb_next(&entry->offset_index);
2052 rb_erase(&entry->offset_index, &cluster->root);
2053
2054 bitmap = (entry->bitmap != NULL);
2055 if (!bitmap)
2056 try_merge_free_space(ctl, entry, false);
2057 tree_insert_offset(&ctl->free_space_offset,
2058 entry->offset, &entry->offset_index, bitmap);
2059 }
2060 cluster->root = RB_ROOT;
2061
2062 out:
2063 spin_unlock(&cluster->lock);
2064 btrfs_put_block_group(block_group);
2065 return 0;
2066 }
2067
2068 static void __btrfs_remove_free_space_cache_locked(
2069 struct btrfs_free_space_ctl *ctl)
2070 {
2071 struct btrfs_free_space *info;
2072 struct rb_node *node;
2073
2074 while ((node = rb_last(&ctl->free_space_offset)) != NULL) {
2075 info = rb_entry(node, struct btrfs_free_space, offset_index);
2076 if (!info->bitmap) {
2077 unlink_free_space(ctl, info);
2078 kmem_cache_free(btrfs_free_space_cachep, info);
2079 } else {
2080 free_bitmap(ctl, info);
2081 }
2082 if (need_resched()) {
2083 spin_unlock(&ctl->tree_lock);
2084 cond_resched();
2085 spin_lock(&ctl->tree_lock);
2086 }
2087 }
2088 }
2089
2090 void __btrfs_remove_free_space_cache(struct btrfs_free_space_ctl *ctl)
2091 {
2092 spin_lock(&ctl->tree_lock);
2093 __btrfs_remove_free_space_cache_locked(ctl);
2094 spin_unlock(&ctl->tree_lock);
2095 }
2096
2097 void btrfs_remove_free_space_cache(struct btrfs_block_group_cache *block_group)
2098 {
2099 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2100 struct btrfs_free_cluster *cluster;
2101 struct list_head *head;
2102
2103 spin_lock(&ctl->tree_lock);
2104 while ((head = block_group->cluster_list.next) !=
2105 &block_group->cluster_list) {
2106 cluster = list_entry(head, struct btrfs_free_cluster,
2107 block_group_list);
2108
2109 WARN_ON(cluster->block_group != block_group);
2110 __btrfs_return_cluster_to_free_space(block_group, cluster);
2111 if (need_resched()) {
2112 spin_unlock(&ctl->tree_lock);
2113 cond_resched();
2114 spin_lock(&ctl->tree_lock);
2115 }
2116 }
2117 __btrfs_remove_free_space_cache_locked(ctl);
2118 spin_unlock(&ctl->tree_lock);
2119
2120 }
2121
2122 u64 btrfs_find_space_for_alloc(struct btrfs_block_group_cache *block_group,
2123 u64 offset, u64 bytes, u64 empty_size)
2124 {
2125 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2126 struct btrfs_free_space *entry = NULL;
2127 u64 bytes_search = bytes + empty_size;
2128 u64 ret = 0;
2129 u64 align_gap = 0;
2130 u64 align_gap_len = 0;
2131
2132 spin_lock(&ctl->tree_lock);
2133 entry = find_free_space(ctl, &offset, &bytes_search,
2134 block_group->full_stripe_len);
2135 if (!entry)
2136 goto out;
2137
2138 ret = offset;
2139 if (entry->bitmap) {
2140 bitmap_clear_bits(ctl, entry, offset, bytes);
2141 if (!entry->bytes)
2142 free_bitmap(ctl, entry);
2143 } else {
2144
2145 unlink_free_space(ctl, entry);
2146 align_gap_len = offset - entry->offset;
2147 align_gap = entry->offset;
2148
2149 entry->offset = offset + bytes;
2150 WARN_ON(entry->bytes < bytes + align_gap_len);
2151
2152 entry->bytes -= bytes + align_gap_len;
2153 if (!entry->bytes)
2154 kmem_cache_free(btrfs_free_space_cachep, entry);
2155 else
2156 link_free_space(ctl, entry);
2157 }
2158
2159 out:
2160 spin_unlock(&ctl->tree_lock);
2161
2162 if (align_gap_len)
2163 __btrfs_add_free_space(ctl, align_gap, align_gap_len);
2164 return ret;
2165 }
2166
2167 /*
2168 * given a cluster, put all of its extents back into the free space
2169 * cache. If a block group is passed, this function will only free
2170 * a cluster that belongs to the passed block group.
2171 *
2172 * Otherwise, it'll get a reference on the block group pointed to by the
2173 * cluster and remove the cluster from it.
2174 */
2175 int btrfs_return_cluster_to_free_space(
2176 struct btrfs_block_group_cache *block_group,
2177 struct btrfs_free_cluster *cluster)
2178 {
2179 struct btrfs_free_space_ctl *ctl;
2180 int ret;
2181
2182 /* first, get a safe pointer to the block group */
2183 spin_lock(&cluster->lock);
2184 if (!block_group) {
2185 block_group = cluster->block_group;
2186 if (!block_group) {
2187 spin_unlock(&cluster->lock);
2188 return 0;
2189 }
2190 } else if (cluster->block_group != block_group) {
2191 /* someone else has already freed it don't redo their work */
2192 spin_unlock(&cluster->lock);
2193 return 0;
2194 }
2195 atomic_inc(&block_group->count);
2196 spin_unlock(&cluster->lock);
2197
2198 ctl = block_group->free_space_ctl;
2199
2200 /* now return any extents the cluster had on it */
2201 spin_lock(&ctl->tree_lock);
2202 ret = __btrfs_return_cluster_to_free_space(block_group, cluster);
2203 spin_unlock(&ctl->tree_lock);
2204
2205 /* finally drop our ref */
2206 btrfs_put_block_group(block_group);
2207 return ret;
2208 }
2209
2210 static u64 btrfs_alloc_from_bitmap(struct btrfs_block_group_cache *block_group,
2211 struct btrfs_free_cluster *cluster,
2212 struct btrfs_free_space *entry,
2213 u64 bytes, u64 min_start)
2214 {
2215 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2216 int err;
2217 u64 search_start = cluster->window_start;
2218 u64 search_bytes = bytes;
2219 u64 ret = 0;
2220
2221 search_start = min_start;
2222 search_bytes = bytes;
2223
2224 err = search_bitmap(ctl, entry, &search_start, &search_bytes);
2225 if (err)
2226 return 0;
2227
2228 ret = search_start;
2229 __bitmap_clear_bits(ctl, entry, ret, bytes);
2230
2231 return ret;
2232 }
2233
2234 /*
2235 * given a cluster, try to allocate 'bytes' from it, returns 0
2236 * if it couldn't find anything suitably large, or a logical disk offset
2237 * if things worked out
2238 */
2239 u64 btrfs_alloc_from_cluster(struct btrfs_block_group_cache *block_group,
2240 struct btrfs_free_cluster *cluster, u64 bytes,
2241 u64 min_start)
2242 {
2243 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2244 struct btrfs_free_space *entry = NULL;
2245 struct rb_node *node;
2246 u64 ret = 0;
2247
2248 spin_lock(&cluster->lock);
2249 if (bytes > cluster->max_size)
2250 goto out;
2251
2252 if (cluster->block_group != block_group)
2253 goto out;
2254
2255 node = rb_first(&cluster->root);
2256 if (!node)
2257 goto out;
2258
2259 entry = rb_entry(node, struct btrfs_free_space, offset_index);
2260 while(1) {
2261 if (entry->bytes < bytes ||
2262 (!entry->bitmap && entry->offset < min_start)) {
2263 node = rb_next(&entry->offset_index);
2264 if (!node)
2265 break;
2266 entry = rb_entry(node, struct btrfs_free_space,
2267 offset_index);
2268 continue;
2269 }
2270
2271 if (entry->bitmap) {
2272 ret = btrfs_alloc_from_bitmap(block_group,
2273 cluster, entry, bytes,
2274 cluster->window_start);
2275 if (ret == 0) {
2276 node = rb_next(&entry->offset_index);
2277 if (!node)
2278 break;
2279 entry = rb_entry(node, struct btrfs_free_space,
2280 offset_index);
2281 continue;
2282 }
2283 cluster->window_start += bytes;
2284 } else {
2285 ret = entry->offset;
2286
2287 entry->offset += bytes;
2288 entry->bytes -= bytes;
2289 }
2290
2291 if (entry->bytes == 0)
2292 rb_erase(&entry->offset_index, &cluster->root);
2293 break;
2294 }
2295 out:
2296 spin_unlock(&cluster->lock);
2297
2298 if (!ret)
2299 return 0;
2300
2301 spin_lock(&ctl->tree_lock);
2302
2303 ctl->free_space -= bytes;
2304 if (entry->bytes == 0) {
2305 ctl->free_extents--;
2306 if (entry->bitmap) {
2307 kfree(entry->bitmap);
2308 ctl->total_bitmaps--;
2309 ctl->op->recalc_thresholds(ctl);
2310 }
2311 kmem_cache_free(btrfs_free_space_cachep, entry);
2312 }
2313
2314 spin_unlock(&ctl->tree_lock);
2315
2316 return ret;
2317 }
2318
2319 static int btrfs_bitmap_cluster(struct btrfs_block_group_cache *block_group,
2320 struct btrfs_free_space *entry,
2321 struct btrfs_free_cluster *cluster,
2322 u64 offset, u64 bytes,
2323 u64 cont1_bytes, u64 min_bytes)
2324 {
2325 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2326 unsigned long next_zero;
2327 unsigned long i;
2328 unsigned long want_bits;
2329 unsigned long min_bits;
2330 unsigned long found_bits;
2331 unsigned long start = 0;
2332 unsigned long total_found = 0;
2333 int ret;
2334
2335 i = offset_to_bit(entry->offset, ctl->unit,
2336 max_t(u64, offset, entry->offset));
2337 want_bits = bytes_to_bits(bytes, ctl->unit);
2338 min_bits = bytes_to_bits(min_bytes, ctl->unit);
2339
2340 again:
2341 found_bits = 0;
2342 for_each_set_bit_from(i, entry->bitmap, BITS_PER_BITMAP) {
2343 next_zero = find_next_zero_bit(entry->bitmap,
2344 BITS_PER_BITMAP, i);
2345 if (next_zero - i >= min_bits) {
2346 found_bits = next_zero - i;
2347 break;
2348 }
2349 i = next_zero;
2350 }
2351
2352 if (!found_bits)
2353 return -ENOSPC;
2354
2355 if (!total_found) {
2356 start = i;
2357 cluster->max_size = 0;
2358 }
2359
2360 total_found += found_bits;
2361
2362 if (cluster->max_size < found_bits * ctl->unit)
2363 cluster->max_size = found_bits * ctl->unit;
2364
2365 if (total_found < want_bits || cluster->max_size < cont1_bytes) {
2366 i = next_zero + 1;
2367 goto again;
2368 }
2369
2370 cluster->window_start = start * ctl->unit + entry->offset;
2371 rb_erase(&entry->offset_index, &ctl->free_space_offset);
2372 ret = tree_insert_offset(&cluster->root, entry->offset,
2373 &entry->offset_index, 1);
2374 BUG_ON(ret); /* -EEXIST; Logic error */
2375
2376 trace_btrfs_setup_cluster(block_group, cluster,
2377 total_found * ctl->unit, 1);
2378 return 0;
2379 }
2380
2381 /*
2382 * This searches the block group for just extents to fill the cluster with.
2383 * Try to find a cluster with at least bytes total bytes, at least one
2384 * extent of cont1_bytes, and other clusters of at least min_bytes.
2385 */
2386 static noinline int
2387 setup_cluster_no_bitmap(struct btrfs_block_group_cache *block_group,
2388 struct btrfs_free_cluster *cluster,
2389 struct list_head *bitmaps, u64 offset, u64 bytes,
2390 u64 cont1_bytes, u64 min_bytes)
2391 {
2392 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2393 struct btrfs_free_space *first = NULL;
2394 struct btrfs_free_space *entry = NULL;
2395 struct btrfs_free_space *last;
2396 struct rb_node *node;
2397 u64 window_start;
2398 u64 window_free;
2399 u64 max_extent;
2400 u64 total_size = 0;
2401
2402 entry = tree_search_offset(ctl, offset, 0, 1);
2403 if (!entry)
2404 return -ENOSPC;
2405
2406 /*
2407 * We don't want bitmaps, so just move along until we find a normal
2408 * extent entry.
2409 */
2410 while (entry->bitmap || entry->bytes < min_bytes) {
2411 if (entry->bitmap && list_empty(&entry->list))
2412 list_add_tail(&entry->list, bitmaps);
2413 node = rb_next(&entry->offset_index);
2414 if (!node)
2415 return -ENOSPC;
2416 entry = rb_entry(node, struct btrfs_free_space, offset_index);
2417 }
2418
2419 window_start = entry->offset;
2420 window_free = entry->bytes;
2421 max_extent = entry->bytes;
2422 first = entry;
2423 last = entry;
2424
2425 for (node = rb_next(&entry->offset_index); node;
2426 node = rb_next(&entry->offset_index)) {
2427 entry = rb_entry(node, struct btrfs_free_space, offset_index);
2428
2429 if (entry->bitmap) {
2430 if (list_empty(&entry->list))
2431 list_add_tail(&entry->list, bitmaps);
2432 continue;
2433 }
2434
2435 if (entry->bytes < min_bytes)
2436 continue;
2437
2438 last = entry;
2439 window_free += entry->bytes;
2440 if (entry->bytes > max_extent)
2441 max_extent = entry->bytes;
2442 }
2443
2444 if (window_free < bytes || max_extent < cont1_bytes)
2445 return -ENOSPC;
2446
2447 cluster->window_start = first->offset;
2448
2449 node = &first->offset_index;
2450
2451 /*
2452 * now we've found our entries, pull them out of the free space
2453 * cache and put them into the cluster rbtree
2454 */
2455 do {
2456 int ret;
2457
2458 entry = rb_entry(node, struct btrfs_free_space, offset_index);
2459 node = rb_next(&entry->offset_index);
2460 if (entry->bitmap || entry->bytes < min_bytes)
2461 continue;
2462
2463 rb_erase(&entry->offset_index, &ctl->free_space_offset);
2464 ret = tree_insert_offset(&cluster->root, entry->offset,
2465 &entry->offset_index, 0);
2466 total_size += entry->bytes;
2467 BUG_ON(ret); /* -EEXIST; Logic error */
2468 } while (node && entry != last);
2469
2470 cluster->max_size = max_extent;
2471 trace_btrfs_setup_cluster(block_group, cluster, total_size, 0);
2472 return 0;
2473 }
2474
2475 /*
2476 * This specifically looks for bitmaps that may work in the cluster, we assume
2477 * that we have already failed to find extents that will work.
2478 */
2479 static noinline int
2480 setup_cluster_bitmap(struct btrfs_block_group_cache *block_group,
2481 struct btrfs_free_cluster *cluster,
2482 struct list_head *bitmaps, u64 offset, u64 bytes,
2483 u64 cont1_bytes, u64 min_bytes)
2484 {
2485 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2486 struct btrfs_free_space *entry;
2487 int ret = -ENOSPC;
2488 u64 bitmap_offset = offset_to_bitmap(ctl, offset);
2489
2490 if (ctl->total_bitmaps == 0)
2491 return -ENOSPC;
2492
2493 /*
2494 * The bitmap that covers offset won't be in the list unless offset
2495 * is just its start offset.
2496 */
2497 entry = list_first_entry(bitmaps, struct btrfs_free_space, list);
2498 if (entry->offset != bitmap_offset) {
2499 entry = tree_search_offset(ctl, bitmap_offset, 1, 0);
2500 if (entry && list_empty(&entry->list))
2501 list_add(&entry->list, bitmaps);
2502 }
2503
2504 list_for_each_entry(entry, bitmaps, list) {
2505 if (entry->bytes < bytes)
2506 continue;
2507 ret = btrfs_bitmap_cluster(block_group, entry, cluster, offset,
2508 bytes, cont1_bytes, min_bytes);
2509 if (!ret)
2510 return 0;
2511 }
2512
2513 /*
2514 * The bitmaps list has all the bitmaps that record free space
2515 * starting after offset, so no more search is required.
2516 */
2517 return -ENOSPC;
2518 }
2519
2520 /*
2521 * here we try to find a cluster of blocks in a block group. The goal
2522 * is to find at least bytes+empty_size.
2523 * We might not find them all in one contiguous area.
2524 *
2525 * returns zero and sets up cluster if things worked out, otherwise
2526 * it returns -enospc
2527 */
2528 int btrfs_find_space_cluster(struct btrfs_trans_handle *trans,
2529 struct btrfs_root *root,
2530 struct btrfs_block_group_cache *block_group,
2531 struct btrfs_free_cluster *cluster,
2532 u64 offset, u64 bytes, u64 empty_size)
2533 {
2534 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2535 struct btrfs_free_space *entry, *tmp;
2536 LIST_HEAD(bitmaps);
2537 u64 min_bytes;
2538 u64 cont1_bytes;
2539 int ret;
2540
2541 /*
2542 * Choose the minimum extent size we'll require for this
2543 * cluster. For SSD_SPREAD, don't allow any fragmentation.
2544 * For metadata, allow allocates with smaller extents. For
2545 * data, keep it dense.
2546 */
2547 if (btrfs_test_opt(root, SSD_SPREAD)) {
2548 cont1_bytes = min_bytes = bytes + empty_size;
2549 } else if (block_group->flags & BTRFS_BLOCK_GROUP_METADATA) {
2550 cont1_bytes = bytes;
2551 min_bytes = block_group->sectorsize;
2552 } else {
2553 cont1_bytes = max(bytes, (bytes + empty_size) >> 2);
2554 min_bytes = block_group->sectorsize;
2555 }
2556
2557 spin_lock(&ctl->tree_lock);
2558
2559 /*
2560 * If we know we don't have enough space to make a cluster don't even
2561 * bother doing all the work to try and find one.
2562 */
2563 if (ctl->free_space < bytes) {
2564 spin_unlock(&ctl->tree_lock);
2565 return -ENOSPC;
2566 }
2567
2568 spin_lock(&cluster->lock);
2569
2570 /* someone already found a cluster, hooray */
2571 if (cluster->block_group) {
2572 ret = 0;
2573 goto out;
2574 }
2575
2576 trace_btrfs_find_cluster(block_group, offset, bytes, empty_size,
2577 min_bytes);
2578
2579 INIT_LIST_HEAD(&bitmaps);
2580 ret = setup_cluster_no_bitmap(block_group, cluster, &bitmaps, offset,
2581 bytes + empty_size,
2582 cont1_bytes, min_bytes);
2583 if (ret)
2584 ret = setup_cluster_bitmap(block_group, cluster, &bitmaps,
2585 offset, bytes + empty_size,
2586 cont1_bytes, min_bytes);
2587
2588 /* Clear our temporary list */
2589 list_for_each_entry_safe(entry, tmp, &bitmaps, list)
2590 list_del_init(&entry->list);
2591
2592 if (!ret) {
2593 atomic_inc(&block_group->count);
2594 list_add_tail(&cluster->block_group_list,
2595 &block_group->cluster_list);
2596 cluster->block_group = block_group;
2597 } else {
2598 trace_btrfs_failed_cluster_setup(block_group);
2599 }
2600 out:
2601 spin_unlock(&cluster->lock);
2602 spin_unlock(&ctl->tree_lock);
2603
2604 return ret;
2605 }
2606
2607 /*
2608 * simple code to zero out a cluster
2609 */
2610 void btrfs_init_free_cluster(struct btrfs_free_cluster *cluster)
2611 {
2612 spin_lock_init(&cluster->lock);
2613 spin_lock_init(&cluster->refill_lock);
2614 cluster->root = RB_ROOT;
2615 cluster->max_size = 0;
2616 INIT_LIST_HEAD(&cluster->block_group_list);
2617 cluster->block_group = NULL;
2618 }
2619
2620 static int do_trimming(struct btrfs_block_group_cache *block_group,
2621 u64 *total_trimmed, u64 start, u64 bytes,
2622 u64 reserved_start, u64 reserved_bytes)
2623 {
2624 struct btrfs_space_info *space_info = block_group->space_info;
2625 struct btrfs_fs_info *fs_info = block_group->fs_info;
2626 int ret;
2627 int update = 0;
2628 u64 trimmed = 0;
2629
2630 spin_lock(&space_info->lock);
2631 spin_lock(&block_group->lock);
2632 if (!block_group->ro) {
2633 block_group->reserved += reserved_bytes;
2634 space_info->bytes_reserved += reserved_bytes;
2635 update = 1;
2636 }
2637 spin_unlock(&block_group->lock);
2638 spin_unlock(&space_info->lock);
2639
2640 ret = btrfs_error_discard_extent(fs_info->extent_root,
2641 start, bytes, &trimmed);
2642 if (!ret)
2643 *total_trimmed += trimmed;
2644
2645 btrfs_add_free_space(block_group, reserved_start, reserved_bytes);
2646
2647 if (update) {
2648 spin_lock(&space_info->lock);
2649 spin_lock(&block_group->lock);
2650 if (block_group->ro)
2651 space_info->bytes_readonly += reserved_bytes;
2652 block_group->reserved -= reserved_bytes;
2653 space_info->bytes_reserved -= reserved_bytes;
2654 spin_unlock(&space_info->lock);
2655 spin_unlock(&block_group->lock);
2656 }
2657
2658 return ret;
2659 }
2660
2661 static int trim_no_bitmap(struct btrfs_block_group_cache *block_group,
2662 u64 *total_trimmed, u64 start, u64 end, u64 minlen)
2663 {
2664 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2665 struct btrfs_free_space *entry;
2666 struct rb_node *node;
2667 int ret = 0;
2668 u64 extent_start;
2669 u64 extent_bytes;
2670 u64 bytes;
2671
2672 while (start < end) {
2673 spin_lock(&ctl->tree_lock);
2674
2675 if (ctl->free_space < minlen) {
2676 spin_unlock(&ctl->tree_lock);
2677 break;
2678 }
2679
2680 entry = tree_search_offset(ctl, start, 0, 1);
2681 if (!entry) {
2682 spin_unlock(&ctl->tree_lock);
2683 break;
2684 }
2685
2686 /* skip bitmaps */
2687 while (entry->bitmap) {
2688 node = rb_next(&entry->offset_index);
2689 if (!node) {
2690 spin_unlock(&ctl->tree_lock);
2691 goto out;
2692 }
2693 entry = rb_entry(node, struct btrfs_free_space,
2694 offset_index);
2695 }
2696
2697 if (entry->offset >= end) {
2698 spin_unlock(&ctl->tree_lock);
2699 break;
2700 }
2701
2702 extent_start = entry->offset;
2703 extent_bytes = entry->bytes;
2704 start = max(start, extent_start);
2705 bytes = min(extent_start + extent_bytes, end) - start;
2706 if (bytes < minlen) {
2707 spin_unlock(&ctl->tree_lock);
2708 goto next;
2709 }
2710
2711 unlink_free_space(ctl, entry);
2712 kmem_cache_free(btrfs_free_space_cachep, entry);
2713
2714 spin_unlock(&ctl->tree_lock);
2715
2716 ret = do_trimming(block_group, total_trimmed, start, bytes,
2717 extent_start, extent_bytes);
2718 if (ret)
2719 break;
2720 next:
2721 start += bytes;
2722
2723 if (fatal_signal_pending(current)) {
2724 ret = -ERESTARTSYS;
2725 break;
2726 }
2727
2728 cond_resched();
2729 }
2730 out:
2731 return ret;
2732 }
2733
2734 static int trim_bitmaps(struct btrfs_block_group_cache *block_group,
2735 u64 *total_trimmed, u64 start, u64 end, u64 minlen)
2736 {
2737 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2738 struct btrfs_free_space *entry;
2739 int ret = 0;
2740 int ret2;
2741 u64 bytes;
2742 u64 offset = offset_to_bitmap(ctl, start);
2743
2744 while (offset < end) {
2745 bool next_bitmap = false;
2746
2747 spin_lock(&ctl->tree_lock);
2748
2749 if (ctl->free_space < minlen) {
2750 spin_unlock(&ctl->tree_lock);
2751 break;
2752 }
2753
2754 entry = tree_search_offset(ctl, offset, 1, 0);
2755 if (!entry) {
2756 spin_unlock(&ctl->tree_lock);
2757 next_bitmap = true;
2758 goto next;
2759 }
2760
2761 bytes = minlen;
2762 ret2 = search_bitmap(ctl, entry, &start, &bytes);
2763 if (ret2 || start >= end) {
2764 spin_unlock(&ctl->tree_lock);
2765 next_bitmap = true;
2766 goto next;
2767 }
2768
2769 bytes = min(bytes, end - start);
2770 if (bytes < minlen) {
2771 spin_unlock(&ctl->tree_lock);
2772 goto next;
2773 }
2774
2775 bitmap_clear_bits(ctl, entry, start, bytes);
2776 if (entry->bytes == 0)
2777 free_bitmap(ctl, entry);
2778
2779 spin_unlock(&ctl->tree_lock);
2780
2781 ret = do_trimming(block_group, total_trimmed, start, bytes,
2782 start, bytes);
2783 if (ret)
2784 break;
2785 next:
2786 if (next_bitmap) {
2787 offset += BITS_PER_BITMAP * ctl->unit;
2788 } else {
2789 start += bytes;
2790 if (start >= offset + BITS_PER_BITMAP * ctl->unit)
2791 offset += BITS_PER_BITMAP * ctl->unit;
2792 }
2793
2794 if (fatal_signal_pending(current)) {
2795 ret = -ERESTARTSYS;
2796 break;
2797 }
2798
2799 cond_resched();
2800 }
2801
2802 return ret;
2803 }
2804
2805 int btrfs_trim_block_group(struct btrfs_block_group_cache *block_group,
2806 u64 *trimmed, u64 start, u64 end, u64 minlen)
2807 {
2808 int ret;
2809
2810 *trimmed = 0;
2811
2812 ret = trim_no_bitmap(block_group, trimmed, start, end, minlen);
2813 if (ret)
2814 return ret;
2815
2816 ret = trim_bitmaps(block_group, trimmed, start, end, minlen);
2817
2818 return ret;
2819 }
2820
2821 /*
2822 * Find the left-most item in the cache tree, and then return the
2823 * smallest inode number in the item.
2824 *
2825 * Note: the returned inode number may not be the smallest one in
2826 * the tree, if the left-most item is a bitmap.
2827 */
2828 u64 btrfs_find_ino_for_alloc(struct btrfs_root *fs_root)
2829 {
2830 struct btrfs_free_space_ctl *ctl = fs_root->free_ino_ctl;
2831 struct btrfs_free_space *entry = NULL;
2832 u64 ino = 0;
2833
2834 spin_lock(&ctl->tree_lock);
2835
2836 if (RB_EMPTY_ROOT(&ctl->free_space_offset))
2837 goto out;
2838
2839 entry = rb_entry(rb_first(&ctl->free_space_offset),
2840 struct btrfs_free_space, offset_index);
2841
2842 if (!entry->bitmap) {
2843 ino = entry->offset;
2844
2845 unlink_free_space(ctl, entry);
2846 entry->offset++;
2847 entry->bytes--;
2848 if (!entry->bytes)
2849 kmem_cache_free(btrfs_free_space_cachep, entry);
2850 else
2851 link_free_space(ctl, entry);
2852 } else {
2853 u64 offset = 0;
2854 u64 count = 1;
2855 int ret;
2856
2857 ret = search_bitmap(ctl, entry, &offset, &count);
2858 /* Logic error; Should be empty if it can't find anything */
2859 BUG_ON(ret);
2860
2861 ino = offset;
2862 bitmap_clear_bits(ctl, entry, offset, 1);
2863 if (entry->bytes == 0)
2864 free_bitmap(ctl, entry);
2865 }
2866 out:
2867 spin_unlock(&ctl->tree_lock);
2868
2869 return ino;
2870 }
2871
2872 struct inode *lookup_free_ino_inode(struct btrfs_root *root,
2873 struct btrfs_path *path)
2874 {
2875 struct inode *inode = NULL;
2876
2877 spin_lock(&root->cache_lock);
2878 if (root->cache_inode)
2879 inode = igrab(root->cache_inode);
2880 spin_unlock(&root->cache_lock);
2881 if (inode)
2882 return inode;
2883
2884 inode = __lookup_free_space_inode(root, path, 0);
2885 if (IS_ERR(inode))
2886 return inode;
2887
2888 spin_lock(&root->cache_lock);
2889 if (!btrfs_fs_closing(root->fs_info))
2890 root->cache_inode = igrab(inode);
2891 spin_unlock(&root->cache_lock);
2892
2893 return inode;
2894 }
2895
2896 int create_free_ino_inode(struct btrfs_root *root,
2897 struct btrfs_trans_handle *trans,
2898 struct btrfs_path *path)
2899 {
2900 return __create_free_space_inode(root, trans, path,
2901 BTRFS_FREE_INO_OBJECTID, 0);
2902 }
2903
2904 int load_free_ino_cache(struct btrfs_fs_info *fs_info, struct btrfs_root *root)
2905 {
2906 struct btrfs_free_space_ctl *ctl = root->free_ino_ctl;
2907 struct btrfs_path *path;
2908 struct inode *inode;
2909 int ret = 0;
2910 u64 root_gen = btrfs_root_generation(&root->root_item);
2911
2912 if (!btrfs_test_opt(root, INODE_MAP_CACHE))
2913 return 0;
2914
2915 /*
2916 * If we're unmounting then just return, since this does a search on the
2917 * normal root and not the commit root and we could deadlock.
2918 */
2919 if (btrfs_fs_closing(fs_info))
2920 return 0;
2921
2922 path = btrfs_alloc_path();
2923 if (!path)
2924 return 0;
2925
2926 inode = lookup_free_ino_inode(root, path);
2927 if (IS_ERR(inode))
2928 goto out;
2929
2930 if (root_gen != BTRFS_I(inode)->generation)
2931 goto out_put;
2932
2933 ret = __load_free_space_cache(root, inode, ctl, path, 0);
2934
2935 if (ret < 0)
2936 btrfs_err(fs_info,
2937 "failed to load free ino cache for root %llu",
2938 root->root_key.objectid);
2939 out_put:
2940 iput(inode);
2941 out:
2942 btrfs_free_path(path);
2943 return ret;
2944 }
2945
2946 int btrfs_write_out_ino_cache(struct btrfs_root *root,
2947 struct btrfs_trans_handle *trans,
2948 struct btrfs_path *path)
2949 {
2950 struct btrfs_free_space_ctl *ctl = root->free_ino_ctl;
2951 struct inode *inode;
2952 int ret;
2953
2954 if (!btrfs_test_opt(root, INODE_MAP_CACHE))
2955 return 0;
2956
2957 inode = lookup_free_ino_inode(root, path);
2958 if (IS_ERR(inode))
2959 return 0;
2960
2961 ret = __btrfs_write_out_cache(root, inode, ctl, NULL, trans, path, 0);
2962 if (ret) {
2963 btrfs_delalloc_release_metadata(inode, inode->i_size);
2964 #ifdef DEBUG
2965 btrfs_err(root->fs_info,
2966 "failed to write free ino cache for root %llu",
2967 root->root_key.objectid);
2968 #endif
2969 }
2970
2971 iput(inode);
2972 return ret;
2973 }
2974
2975 #ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
2976 static struct btrfs_block_group_cache *init_test_block_group(void)
2977 {
2978 struct btrfs_block_group_cache *cache;
2979
2980 cache = kzalloc(sizeof(*cache), GFP_NOFS);
2981 if (!cache)
2982 return NULL;
2983 cache->free_space_ctl = kzalloc(sizeof(*cache->free_space_ctl),
2984 GFP_NOFS);
2985 if (!cache->free_space_ctl) {
2986 kfree(cache);
2987 return NULL;
2988 }
2989
2990 cache->key.objectid = 0;
2991 cache->key.offset = 1024 * 1024 * 1024;
2992 cache->key.type = BTRFS_BLOCK_GROUP_ITEM_KEY;
2993 cache->sectorsize = 4096;
2994
2995 spin_lock_init(&cache->lock);
2996 INIT_LIST_HEAD(&cache->list);
2997 INIT_LIST_HEAD(&cache->cluster_list);
2998 INIT_LIST_HEAD(&cache->new_bg_list);
2999
3000 btrfs_init_free_space_ctl(cache);
3001
3002 return cache;
3003 }
3004
3005 /*
3006 * Checks to see if the given range is in the free space cache. This is really
3007 * just used to check the absence of space, so if there is free space in the
3008 * range at all we will return 1.
3009 */
3010 static int check_exists(struct btrfs_block_group_cache *cache, u64 offset,
3011 u64 bytes)
3012 {
3013 struct btrfs_free_space_ctl *ctl = cache->free_space_ctl;
3014 struct btrfs_free_space *info;
3015 int ret = 0;
3016
3017 spin_lock(&ctl->tree_lock);
3018 info = tree_search_offset(ctl, offset, 0, 0);
3019 if (!info) {
3020 info = tree_search_offset(ctl, offset_to_bitmap(ctl, offset),
3021 1, 0);
3022 if (!info)
3023 goto out;
3024 }
3025
3026 have_info:
3027 if (info->bitmap) {
3028 u64 bit_off, bit_bytes;
3029 struct rb_node *n;
3030 struct btrfs_free_space *tmp;
3031
3032 bit_off = offset;
3033 bit_bytes = ctl->unit;
3034 ret = search_bitmap(ctl, info, &bit_off, &bit_bytes);
3035 if (!ret) {
3036 if (bit_off == offset) {
3037 ret = 1;
3038 goto out;
3039 } else if (bit_off > offset &&
3040 offset + bytes > bit_off) {
3041 ret = 1;
3042 goto out;
3043 }
3044 }
3045
3046 n = rb_prev(&info->offset_index);
3047 while (n) {
3048 tmp = rb_entry(n, struct btrfs_free_space,
3049 offset_index);
3050 if (tmp->offset + tmp->bytes < offset)
3051 break;
3052 if (offset + bytes < tmp->offset) {
3053 n = rb_prev(&info->offset_index);
3054 continue;
3055 }
3056 info = tmp;
3057 goto have_info;
3058 }
3059
3060 n = rb_next(&info->offset_index);
3061 while (n) {
3062 tmp = rb_entry(n, struct btrfs_free_space,
3063 offset_index);
3064 if (offset + bytes < tmp->offset)
3065 break;
3066 if (tmp->offset + tmp->bytes < offset) {
3067 n = rb_next(&info->offset_index);
3068 continue;
3069 }
3070 info = tmp;
3071 goto have_info;
3072 }
3073
3074 goto out;
3075 }
3076
3077 if (info->offset == offset) {
3078 ret = 1;
3079 goto out;
3080 }
3081
3082 if (offset > info->offset && offset < info->offset + info->bytes)
3083 ret = 1;
3084 out:
3085 spin_unlock(&ctl->tree_lock);
3086 return ret;
3087 }
3088
3089 /*
3090 * Use this if you need to make a bitmap or extent entry specifically, it
3091 * doesn't do any of the merging that add_free_space does, this acts a lot like
3092 * how the free space cache loading stuff works, so you can get really weird
3093 * configurations.
3094 */
3095 static int add_free_space_entry(struct btrfs_block_group_cache *cache,
3096 u64 offset, u64 bytes, bool bitmap)
3097 {
3098 struct btrfs_free_space_ctl *ctl = cache->free_space_ctl;
3099 struct btrfs_free_space *info = NULL, *bitmap_info;
3100 void *map = NULL;
3101 u64 bytes_added;
3102 int ret;
3103
3104 again:
3105 if (!info) {
3106 info = kmem_cache_zalloc(btrfs_free_space_cachep, GFP_NOFS);
3107 if (!info)
3108 return -ENOMEM;
3109 }
3110
3111 if (!bitmap) {
3112 spin_lock(&ctl->tree_lock);
3113 info->offset = offset;
3114 info->bytes = bytes;
3115 ret = link_free_space(ctl, info);
3116 spin_unlock(&ctl->tree_lock);
3117 if (ret)
3118 kmem_cache_free(btrfs_free_space_cachep, info);
3119 return ret;
3120 }
3121
3122 if (!map) {
3123 map = kzalloc(PAGE_CACHE_SIZE, GFP_NOFS);
3124 if (!map) {
3125 kmem_cache_free(btrfs_free_space_cachep, info);
3126 return -ENOMEM;
3127 }
3128 }
3129
3130 spin_lock(&ctl->tree_lock);
3131 bitmap_info = tree_search_offset(ctl, offset_to_bitmap(ctl, offset),
3132 1, 0);
3133 if (!bitmap_info) {
3134 info->bitmap = map;
3135 map = NULL;
3136 add_new_bitmap(ctl, info, offset);
3137 bitmap_info = info;
3138 }
3139
3140 bytes_added = add_bytes_to_bitmap(ctl, bitmap_info, offset, bytes);
3141 bytes -= bytes_added;
3142 offset += bytes_added;
3143 spin_unlock(&ctl->tree_lock);
3144
3145 if (bytes)
3146 goto again;
3147
3148 if (map)
3149 kfree(map);
3150 return 0;
3151 }
3152
3153 #define test_msg(fmt, ...) printk(KERN_INFO "btrfs: selftest: " fmt, ##__VA_ARGS__)
3154
3155 /*
3156 * This test just does basic sanity checking, making sure we can add an exten
3157 * entry and remove space from either end and the middle, and make sure we can
3158 * remove space that covers adjacent extent entries.
3159 */
3160 static int test_extents(struct btrfs_block_group_cache *cache)
3161 {
3162 int ret = 0;
3163
3164 test_msg("Running extent only tests\n");
3165
3166 /* First just make sure we can remove an entire entry */
3167 ret = btrfs_add_free_space(cache, 0, 4 * 1024 * 1024);
3168 if (ret) {
3169 test_msg("Error adding initial extents %d\n", ret);
3170 return ret;
3171 }
3172
3173 ret = btrfs_remove_free_space(cache, 0, 4 * 1024 * 1024);
3174 if (ret) {
3175 test_msg("Error removing extent %d\n", ret);
3176 return ret;
3177 }
3178
3179 if (check_exists(cache, 0, 4 * 1024 * 1024)) {
3180 test_msg("Full remove left some lingering space\n");
3181 return -1;
3182 }
3183
3184 /* Ok edge and middle cases now */
3185 ret = btrfs_add_free_space(cache, 0, 4 * 1024 * 1024);
3186 if (ret) {
3187 test_msg("Error adding half extent %d\n", ret);
3188 return ret;
3189 }
3190
3191 ret = btrfs_remove_free_space(cache, 3 * 1024 * 1024, 1 * 1024 * 1024);
3192 if (ret) {
3193 test_msg("Error removing tail end %d\n", ret);
3194 return ret;
3195 }
3196
3197 ret = btrfs_remove_free_space(cache, 0, 1 * 1024 * 1024);
3198 if (ret) {
3199 test_msg("Error removing front end %d\n", ret);
3200 return ret;
3201 }
3202
3203 ret = btrfs_remove_free_space(cache, 2 * 1024 * 1024, 4096);
3204 if (ret) {
3205 test_msg("Error removing middle piece %d\n", ret);
3206 return ret;
3207 }
3208
3209 if (check_exists(cache, 0, 1 * 1024 * 1024)) {
3210 test_msg("Still have space at the front\n");
3211 return -1;
3212 }
3213
3214 if (check_exists(cache, 2 * 1024 * 1024, 4096)) {
3215 test_msg("Still have space in the middle\n");
3216 return -1;
3217 }
3218
3219 if (check_exists(cache, 3 * 1024 * 1024, 1 * 1024 * 1024)) {
3220 test_msg("Still have space at the end\n");
3221 return -1;
3222 }
3223
3224 /* Cleanup */
3225 __btrfs_remove_free_space_cache(cache->free_space_ctl);
3226
3227 return 0;
3228 }
3229
3230 static int test_bitmaps(struct btrfs_block_group_cache *cache)
3231 {
3232 u64 next_bitmap_offset;
3233 int ret;
3234
3235 test_msg("Running bitmap only tests\n");
3236
3237 ret = add_free_space_entry(cache, 0, 4 * 1024 * 1024, 1);
3238 if (ret) {
3239 test_msg("Couldn't create a bitmap entry %d\n", ret);
3240 return ret;
3241 }
3242
3243 ret = btrfs_remove_free_space(cache, 0, 4 * 1024 * 1024);
3244 if (ret) {
3245 test_msg("Error removing bitmap full range %d\n", ret);
3246 return ret;
3247 }
3248
3249 if (check_exists(cache, 0, 4 * 1024 * 1024)) {
3250 test_msg("Left some space in bitmap\n");
3251 return -1;
3252 }
3253
3254 ret = add_free_space_entry(cache, 0, 4 * 1024 * 1024, 1);
3255 if (ret) {
3256 test_msg("Couldn't add to our bitmap entry %d\n", ret);
3257 return ret;
3258 }
3259
3260 ret = btrfs_remove_free_space(cache, 1 * 1024 * 1024, 2 * 1024 * 1024);
3261 if (ret) {
3262 test_msg("Couldn't remove middle chunk %d\n", ret);
3263 return ret;
3264 }
3265
3266 /*
3267 * The first bitmap we have starts at offset 0 so the next one is just
3268 * at the end of the first bitmap.
3269 */
3270 next_bitmap_offset = (u64)(BITS_PER_BITMAP * 4096);
3271
3272 /* Test a bit straddling two bitmaps */
3273 ret = add_free_space_entry(cache, next_bitmap_offset -
3274 (2 * 1024 * 1024), 4 * 1024 * 1024, 1);
3275 if (ret) {
3276 test_msg("Couldn't add space that straddles two bitmaps %d\n",
3277 ret);
3278 return ret;
3279 }
3280
3281 ret = btrfs_remove_free_space(cache, next_bitmap_offset -
3282 (1 * 1024 * 1024), 2 * 1024 * 1024);
3283 if (ret) {
3284 test_msg("Couldn't remove overlapping space %d\n", ret);
3285 return ret;
3286 }
3287
3288 if (check_exists(cache, next_bitmap_offset - (1 * 1024 * 1024),
3289 2 * 1024 * 1024)) {
3290 test_msg("Left some space when removing overlapping\n");
3291 return -1;
3292 }
3293
3294 __btrfs_remove_free_space_cache(cache->free_space_ctl);
3295
3296 return 0;
3297 }
3298
3299 /* This is the high grade jackassery */
3300 static int test_bitmaps_and_extents(struct btrfs_block_group_cache *cache)
3301 {
3302 u64 bitmap_offset = (u64)(BITS_PER_BITMAP * 4096);
3303 int ret;
3304
3305 test_msg("Running bitmap and extent tests\n");
3306
3307 /*
3308 * First let's do something simple, an extent at the same offset as the
3309 * bitmap, but the free space completely in the extent and then
3310 * completely in the bitmap.
3311 */
3312 ret = add_free_space_entry(cache, 4 * 1024 * 1024, 1 * 1024 * 1024, 1);
3313 if (ret) {
3314 test_msg("Couldn't create bitmap entry %d\n", ret);
3315 return ret;
3316 }
3317
3318 ret = add_free_space_entry(cache, 0, 1 * 1024 * 1024, 0);
3319 if (ret) {
3320 test_msg("Couldn't add extent entry %d\n", ret);
3321 return ret;
3322 }
3323
3324 ret = btrfs_remove_free_space(cache, 0, 1 * 1024 * 1024);
3325 if (ret) {
3326 test_msg("Couldn't remove extent entry %d\n", ret);
3327 return ret;
3328 }
3329
3330 if (check_exists(cache, 0, 1 * 1024 * 1024)) {
3331 test_msg("Left remnants after our remove\n");
3332 return -1;
3333 }
3334
3335 /* Now to add back the extent entry and remove from the bitmap */
3336 ret = add_free_space_entry(cache, 0, 1 * 1024 * 1024, 0);
3337 if (ret) {
3338 test_msg("Couldn't re-add extent entry %d\n", ret);
3339 return ret;
3340 }
3341
3342 ret = btrfs_remove_free_space(cache, 4 * 1024 * 1024, 1 * 1024 * 1024);
3343 if (ret) {
3344 test_msg("Couldn't remove from bitmap %d\n", ret);
3345 return ret;
3346 }
3347
3348 if (check_exists(cache, 4 * 1024 * 1024, 1 * 1024 * 1024)) {
3349 test_msg("Left remnants in the bitmap\n");
3350 return -1;
3351 }
3352
3353 /*
3354 * Ok so a little more evil, extent entry and bitmap at the same offset,
3355 * removing an overlapping chunk.
3356 */
3357 ret = add_free_space_entry(cache, 1 * 1024 * 1024, 4 * 1024 * 1024, 1);
3358 if (ret) {
3359 test_msg("Couldn't add to a bitmap %d\n", ret);
3360 return ret;
3361 }
3362
3363 ret = btrfs_remove_free_space(cache, 512 * 1024, 3 * 1024 * 1024);
3364 if (ret) {
3365 test_msg("Couldn't remove overlapping space %d\n", ret);
3366 return ret;
3367 }
3368
3369 if (check_exists(cache, 512 * 1024, 3 * 1024 * 1024)) {
3370 test_msg("Left over peices after removing overlapping\n");
3371 return -1;
3372 }
3373
3374 __btrfs_remove_free_space_cache(cache->free_space_ctl);
3375
3376 /* Now with the extent entry offset into the bitmap */
3377 ret = add_free_space_entry(cache, 4 * 1024 * 1024, 4 * 1024 * 1024, 1);
3378 if (ret) {
3379 test_msg("Couldn't add space to the bitmap %d\n", ret);
3380 return ret;
3381 }
3382
3383 ret = add_free_space_entry(cache, 2 * 1024 * 1024, 2 * 1024 * 1024, 0);
3384 if (ret) {
3385 test_msg("Couldn't add extent to the cache %d\n", ret);
3386 return ret;
3387 }
3388
3389 ret = btrfs_remove_free_space(cache, 3 * 1024 * 1024, 4 * 1024 * 1024);
3390 if (ret) {
3391 test_msg("Problem removing overlapping space %d\n", ret);
3392 return ret;
3393 }
3394
3395 if (check_exists(cache, 3 * 1024 * 1024, 4 * 1024 * 1024)) {
3396 test_msg("Left something behind when removing space");
3397 return -1;
3398 }
3399
3400 /*
3401 * This has blown up in the past, the extent entry starts before the
3402 * bitmap entry, but we're trying to remove an offset that falls
3403 * completely within the bitmap range and is in both the extent entry
3404 * and the bitmap entry, looks like this
3405 *
3406 * [ extent ]
3407 * [ bitmap ]
3408 * [ del ]
3409 */
3410 __btrfs_remove_free_space_cache(cache->free_space_ctl);
3411 ret = add_free_space_entry(cache, bitmap_offset + 4 * 1024 * 1024,
3412 4 * 1024 * 1024, 1);
3413 if (ret) {
3414 test_msg("Couldn't add bitmap %d\n", ret);
3415 return ret;
3416 }
3417
3418 ret = add_free_space_entry(cache, bitmap_offset - 1 * 1024 * 1024,
3419 5 * 1024 * 1024, 0);
3420 if (ret) {
3421 test_msg("Couldn't add extent entry %d\n", ret);
3422 return ret;
3423 }
3424
3425 ret = btrfs_remove_free_space(cache, bitmap_offset + 1 * 1024 * 1024,
3426 5 * 1024 * 1024);
3427 if (ret) {
3428 test_msg("Failed to free our space %d\n", ret);
3429 return ret;
3430 }
3431
3432 if (check_exists(cache, bitmap_offset + 1 * 1024 * 1024,
3433 5 * 1024 * 1024)) {
3434 test_msg("Left stuff over\n");
3435 return -1;
3436 }
3437
3438 __btrfs_remove_free_space_cache(cache->free_space_ctl);
3439
3440 /*
3441 * This blew up before, we have part of the free space in a bitmap and
3442 * then the entirety of the rest of the space in an extent. This used
3443 * to return -EAGAIN back from btrfs_remove_extent, make sure this
3444 * doesn't happen.
3445 */
3446 ret = add_free_space_entry(cache, 1 * 1024 * 1024, 2 * 1024 * 1024, 1);
3447 if (ret) {
3448 test_msg("Couldn't add bitmap entry %d\n", ret);
3449 return ret;
3450 }
3451
3452 ret = add_free_space_entry(cache, 3 * 1024 * 1024, 1 * 1024 * 1024, 0);
3453 if (ret) {
3454 test_msg("Couldn't add extent entry %d\n", ret);
3455 return ret;
3456 }
3457
3458 ret = btrfs_remove_free_space(cache, 1 * 1024 * 1024, 3 * 1024 * 1024);
3459 if (ret) {
3460 test_msg("Error removing bitmap and extent overlapping %d\n", ret);
3461 return ret;
3462 }
3463
3464 __btrfs_remove_free_space_cache(cache->free_space_ctl);
3465 return 0;
3466 }
3467
3468 void btrfs_test_free_space_cache(void)
3469 {
3470 struct btrfs_block_group_cache *cache;
3471
3472 test_msg("Running btrfs free space cache tests\n");
3473
3474 cache = init_test_block_group();
3475 if (!cache) {
3476 test_msg("Couldn't run the tests\n");
3477 return;
3478 }
3479
3480 if (test_extents(cache))
3481 goto out;
3482 if (test_bitmaps(cache))
3483 goto out;
3484 if (test_bitmaps_and_extents(cache))
3485 goto out;
3486 out:
3487 __btrfs_remove_free_space_cache(cache->free_space_ctl);
3488 kfree(cache->free_space_ctl);
3489 kfree(cache);
3490 test_msg("Free space cache tests finished\n");
3491 }
3492 #undef test_msg
3493 #else /* !CONFIG_BTRFS_FS_RUN_SANITY_TESTS */
3494 void btrfs_test_free_space_cache(void) {}
3495 #endif /* !CONFIG_BTRFS_FS_RUN_SANITY_TESTS */
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