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Merge branch 'linux-3.16' of git://anongit.freedesktop.org/git/nouveau/linux-2.6...
[deliverable/linux.git] / fs / btrfs / free-space-cache.c
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 inode *inode)
222 {
223 int ret = 0;
224
225 btrfs_i_size_write(inode, 0);
226 truncate_pagecache(inode, 0);
227
228 /*
229 * We don't need an orphan item because truncating the free space cache
230 * will never be split across transactions.
231 */
232 ret = btrfs_truncate_inode_items(trans, root, inode,
233 0, BTRFS_EXTENT_DATA_KEY);
234 if (ret) {
235 btrfs_abort_transaction(trans, root, ret);
236 return ret;
237 }
238
239 ret = btrfs_update_inode(trans, root, inode);
240 if (ret)
241 btrfs_abort_transaction(trans, root, ret);
242
243 return ret;
244 }
245
246 static int readahead_cache(struct inode *inode)
247 {
248 struct file_ra_state *ra;
249 unsigned long last_index;
250
251 ra = kzalloc(sizeof(*ra), GFP_NOFS);
252 if (!ra)
253 return -ENOMEM;
254
255 file_ra_state_init(ra, inode->i_mapping);
256 last_index = (i_size_read(inode) - 1) >> PAGE_CACHE_SHIFT;
257
258 page_cache_sync_readahead(inode->i_mapping, ra, NULL, 0, last_index);
259
260 kfree(ra);
261
262 return 0;
263 }
264
265 struct io_ctl {
266 void *cur, *orig;
267 struct page *page;
268 struct page **pages;
269 struct btrfs_root *root;
270 unsigned long size;
271 int index;
272 int num_pages;
273 unsigned check_crcs:1;
274 };
275
276 static int io_ctl_init(struct io_ctl *io_ctl, struct inode *inode,
277 struct btrfs_root *root, int write)
278 {
279 int num_pages;
280 int check_crcs = 0;
281
282 num_pages = (i_size_read(inode) + PAGE_CACHE_SIZE - 1) >>
283 PAGE_CACHE_SHIFT;
284
285 if (btrfs_ino(inode) != BTRFS_FREE_INO_OBJECTID)
286 check_crcs = 1;
287
288 /* Make sure we can fit our crcs into the first page */
289 if (write && check_crcs &&
290 (num_pages * sizeof(u32)) >= PAGE_CACHE_SIZE)
291 return -ENOSPC;
292
293 memset(io_ctl, 0, sizeof(struct io_ctl));
294
295 io_ctl->pages = kzalloc(sizeof(struct page *) * num_pages, GFP_NOFS);
296 if (!io_ctl->pages)
297 return -ENOMEM;
298
299 io_ctl->num_pages = num_pages;
300 io_ctl->root = root;
301 io_ctl->check_crcs = check_crcs;
302
303 return 0;
304 }
305
306 static void io_ctl_free(struct io_ctl *io_ctl)
307 {
308 kfree(io_ctl->pages);
309 }
310
311 static void io_ctl_unmap_page(struct io_ctl *io_ctl)
312 {
313 if (io_ctl->cur) {
314 kunmap(io_ctl->page);
315 io_ctl->cur = NULL;
316 io_ctl->orig = NULL;
317 }
318 }
319
320 static void io_ctl_map_page(struct io_ctl *io_ctl, int clear)
321 {
322 ASSERT(io_ctl->index < io_ctl->num_pages);
323 io_ctl->page = io_ctl->pages[io_ctl->index++];
324 io_ctl->cur = kmap(io_ctl->page);
325 io_ctl->orig = io_ctl->cur;
326 io_ctl->size = PAGE_CACHE_SIZE;
327 if (clear)
328 memset(io_ctl->cur, 0, PAGE_CACHE_SIZE);
329 }
330
331 static void io_ctl_drop_pages(struct io_ctl *io_ctl)
332 {
333 int i;
334
335 io_ctl_unmap_page(io_ctl);
336
337 for (i = 0; i < io_ctl->num_pages; i++) {
338 if (io_ctl->pages[i]) {
339 ClearPageChecked(io_ctl->pages[i]);
340 unlock_page(io_ctl->pages[i]);
341 page_cache_release(io_ctl->pages[i]);
342 }
343 }
344 }
345
346 static int io_ctl_prepare_pages(struct io_ctl *io_ctl, struct inode *inode,
347 int uptodate)
348 {
349 struct page *page;
350 gfp_t mask = btrfs_alloc_write_mask(inode->i_mapping);
351 int i;
352
353 for (i = 0; i < io_ctl->num_pages; i++) {
354 page = find_or_create_page(inode->i_mapping, i, mask);
355 if (!page) {
356 io_ctl_drop_pages(io_ctl);
357 return -ENOMEM;
358 }
359 io_ctl->pages[i] = page;
360 if (uptodate && !PageUptodate(page)) {
361 btrfs_readpage(NULL, page);
362 lock_page(page);
363 if (!PageUptodate(page)) {
364 btrfs_err(BTRFS_I(inode)->root->fs_info,
365 "error reading free space cache");
366 io_ctl_drop_pages(io_ctl);
367 return -EIO;
368 }
369 }
370 }
371
372 for (i = 0; i < io_ctl->num_pages; i++) {
373 clear_page_dirty_for_io(io_ctl->pages[i]);
374 set_page_extent_mapped(io_ctl->pages[i]);
375 }
376
377 return 0;
378 }
379
380 static void io_ctl_set_generation(struct io_ctl *io_ctl, u64 generation)
381 {
382 __le64 *val;
383
384 io_ctl_map_page(io_ctl, 1);
385
386 /*
387 * Skip the csum areas. If we don't check crcs then we just have a
388 * 64bit chunk at the front of the first page.
389 */
390 if (io_ctl->check_crcs) {
391 io_ctl->cur += (sizeof(u32) * io_ctl->num_pages);
392 io_ctl->size -= sizeof(u64) + (sizeof(u32) * io_ctl->num_pages);
393 } else {
394 io_ctl->cur += sizeof(u64);
395 io_ctl->size -= sizeof(u64) * 2;
396 }
397
398 val = io_ctl->cur;
399 *val = cpu_to_le64(generation);
400 io_ctl->cur += sizeof(u64);
401 }
402
403 static int io_ctl_check_generation(struct io_ctl *io_ctl, u64 generation)
404 {
405 __le64 *gen;
406
407 /*
408 * Skip the crc area. If we don't check crcs then we just have a 64bit
409 * chunk at the front of the first page.
410 */
411 if (io_ctl->check_crcs) {
412 io_ctl->cur += sizeof(u32) * io_ctl->num_pages;
413 io_ctl->size -= sizeof(u64) +
414 (sizeof(u32) * io_ctl->num_pages);
415 } else {
416 io_ctl->cur += sizeof(u64);
417 io_ctl->size -= sizeof(u64) * 2;
418 }
419
420 gen = io_ctl->cur;
421 if (le64_to_cpu(*gen) != generation) {
422 printk_ratelimited(KERN_ERR "BTRFS: space cache generation "
423 "(%Lu) does not match inode (%Lu)\n", *gen,
424 generation);
425 io_ctl_unmap_page(io_ctl);
426 return -EIO;
427 }
428 io_ctl->cur += sizeof(u64);
429 return 0;
430 }
431
432 static void io_ctl_set_crc(struct io_ctl *io_ctl, int index)
433 {
434 u32 *tmp;
435 u32 crc = ~(u32)0;
436 unsigned offset = 0;
437
438 if (!io_ctl->check_crcs) {
439 io_ctl_unmap_page(io_ctl);
440 return;
441 }
442
443 if (index == 0)
444 offset = sizeof(u32) * io_ctl->num_pages;
445
446 crc = btrfs_csum_data(io_ctl->orig + offset, crc,
447 PAGE_CACHE_SIZE - offset);
448 btrfs_csum_final(crc, (char *)&crc);
449 io_ctl_unmap_page(io_ctl);
450 tmp = kmap(io_ctl->pages[0]);
451 tmp += index;
452 *tmp = crc;
453 kunmap(io_ctl->pages[0]);
454 }
455
456 static int io_ctl_check_crc(struct io_ctl *io_ctl, int index)
457 {
458 u32 *tmp, val;
459 u32 crc = ~(u32)0;
460 unsigned offset = 0;
461
462 if (!io_ctl->check_crcs) {
463 io_ctl_map_page(io_ctl, 0);
464 return 0;
465 }
466
467 if (index == 0)
468 offset = sizeof(u32) * io_ctl->num_pages;
469
470 tmp = kmap(io_ctl->pages[0]);
471 tmp += index;
472 val = *tmp;
473 kunmap(io_ctl->pages[0]);
474
475 io_ctl_map_page(io_ctl, 0);
476 crc = btrfs_csum_data(io_ctl->orig + offset, crc,
477 PAGE_CACHE_SIZE - offset);
478 btrfs_csum_final(crc, (char *)&crc);
479 if (val != crc) {
480 printk_ratelimited(KERN_ERR "BTRFS: csum mismatch on free "
481 "space cache\n");
482 io_ctl_unmap_page(io_ctl);
483 return -EIO;
484 }
485
486 return 0;
487 }
488
489 static int io_ctl_add_entry(struct io_ctl *io_ctl, u64 offset, u64 bytes,
490 void *bitmap)
491 {
492 struct btrfs_free_space_entry *entry;
493
494 if (!io_ctl->cur)
495 return -ENOSPC;
496
497 entry = io_ctl->cur;
498 entry->offset = cpu_to_le64(offset);
499 entry->bytes = cpu_to_le64(bytes);
500 entry->type = (bitmap) ? BTRFS_FREE_SPACE_BITMAP :
501 BTRFS_FREE_SPACE_EXTENT;
502 io_ctl->cur += sizeof(struct btrfs_free_space_entry);
503 io_ctl->size -= sizeof(struct btrfs_free_space_entry);
504
505 if (io_ctl->size >= sizeof(struct btrfs_free_space_entry))
506 return 0;
507
508 io_ctl_set_crc(io_ctl, io_ctl->index - 1);
509
510 /* No more pages to map */
511 if (io_ctl->index >= io_ctl->num_pages)
512 return 0;
513
514 /* map the next page */
515 io_ctl_map_page(io_ctl, 1);
516 return 0;
517 }
518
519 static int io_ctl_add_bitmap(struct io_ctl *io_ctl, void *bitmap)
520 {
521 if (!io_ctl->cur)
522 return -ENOSPC;
523
524 /*
525 * If we aren't at the start of the current page, unmap this one and
526 * map the next one if there is any left.
527 */
528 if (io_ctl->cur != io_ctl->orig) {
529 io_ctl_set_crc(io_ctl, io_ctl->index - 1);
530 if (io_ctl->index >= io_ctl->num_pages)
531 return -ENOSPC;
532 io_ctl_map_page(io_ctl, 0);
533 }
534
535 memcpy(io_ctl->cur, bitmap, PAGE_CACHE_SIZE);
536 io_ctl_set_crc(io_ctl, io_ctl->index - 1);
537 if (io_ctl->index < io_ctl->num_pages)
538 io_ctl_map_page(io_ctl, 0);
539 return 0;
540 }
541
542 static void io_ctl_zero_remaining_pages(struct io_ctl *io_ctl)
543 {
544 /*
545 * If we're not on the boundary we know we've modified the page and we
546 * need to crc the page.
547 */
548 if (io_ctl->cur != io_ctl->orig)
549 io_ctl_set_crc(io_ctl, io_ctl->index - 1);
550 else
551 io_ctl_unmap_page(io_ctl);
552
553 while (io_ctl->index < io_ctl->num_pages) {
554 io_ctl_map_page(io_ctl, 1);
555 io_ctl_set_crc(io_ctl, io_ctl->index - 1);
556 }
557 }
558
559 static int io_ctl_read_entry(struct io_ctl *io_ctl,
560 struct btrfs_free_space *entry, u8 *type)
561 {
562 struct btrfs_free_space_entry *e;
563 int ret;
564
565 if (!io_ctl->cur) {
566 ret = io_ctl_check_crc(io_ctl, io_ctl->index);
567 if (ret)
568 return ret;
569 }
570
571 e = io_ctl->cur;
572 entry->offset = le64_to_cpu(e->offset);
573 entry->bytes = le64_to_cpu(e->bytes);
574 *type = e->type;
575 io_ctl->cur += sizeof(struct btrfs_free_space_entry);
576 io_ctl->size -= sizeof(struct btrfs_free_space_entry);
577
578 if (io_ctl->size >= sizeof(struct btrfs_free_space_entry))
579 return 0;
580
581 io_ctl_unmap_page(io_ctl);
582
583 return 0;
584 }
585
586 static int io_ctl_read_bitmap(struct io_ctl *io_ctl,
587 struct btrfs_free_space *entry)
588 {
589 int ret;
590
591 ret = io_ctl_check_crc(io_ctl, io_ctl->index);
592 if (ret)
593 return ret;
594
595 memcpy(entry->bitmap, io_ctl->cur, PAGE_CACHE_SIZE);
596 io_ctl_unmap_page(io_ctl);
597
598 return 0;
599 }
600
601 /*
602 * Since we attach pinned extents after the fact we can have contiguous sections
603 * of free space that are split up in entries. This poses a problem with the
604 * tree logging stuff since it could have allocated across what appears to be 2
605 * entries since we would have merged the entries when adding the pinned extents
606 * back to the free space cache. So run through the space cache that we just
607 * loaded and merge contiguous entries. This will make the log replay stuff not
608 * blow up and it will make for nicer allocator behavior.
609 */
610 static void merge_space_tree(struct btrfs_free_space_ctl *ctl)
611 {
612 struct btrfs_free_space *e, *prev = NULL;
613 struct rb_node *n;
614
615 again:
616 spin_lock(&ctl->tree_lock);
617 for (n = rb_first(&ctl->free_space_offset); n; n = rb_next(n)) {
618 e = rb_entry(n, struct btrfs_free_space, offset_index);
619 if (!prev)
620 goto next;
621 if (e->bitmap || prev->bitmap)
622 goto next;
623 if (prev->offset + prev->bytes == e->offset) {
624 unlink_free_space(ctl, prev);
625 unlink_free_space(ctl, e);
626 prev->bytes += e->bytes;
627 kmem_cache_free(btrfs_free_space_cachep, e);
628 link_free_space(ctl, prev);
629 prev = NULL;
630 spin_unlock(&ctl->tree_lock);
631 goto again;
632 }
633 next:
634 prev = e;
635 }
636 spin_unlock(&ctl->tree_lock);
637 }
638
639 static int __load_free_space_cache(struct btrfs_root *root, struct inode *inode,
640 struct btrfs_free_space_ctl *ctl,
641 struct btrfs_path *path, u64 offset)
642 {
643 struct btrfs_free_space_header *header;
644 struct extent_buffer *leaf;
645 struct io_ctl io_ctl;
646 struct btrfs_key key;
647 struct btrfs_free_space *e, *n;
648 struct list_head bitmaps;
649 u64 num_entries;
650 u64 num_bitmaps;
651 u64 generation;
652 u8 type;
653 int ret = 0;
654
655 INIT_LIST_HEAD(&bitmaps);
656
657 /* Nothing in the space cache, goodbye */
658 if (!i_size_read(inode))
659 return 0;
660
661 key.objectid = BTRFS_FREE_SPACE_OBJECTID;
662 key.offset = offset;
663 key.type = 0;
664
665 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
666 if (ret < 0)
667 return 0;
668 else if (ret > 0) {
669 btrfs_release_path(path);
670 return 0;
671 }
672
673 ret = -1;
674
675 leaf = path->nodes[0];
676 header = btrfs_item_ptr(leaf, path->slots[0],
677 struct btrfs_free_space_header);
678 num_entries = btrfs_free_space_entries(leaf, header);
679 num_bitmaps = btrfs_free_space_bitmaps(leaf, header);
680 generation = btrfs_free_space_generation(leaf, header);
681 btrfs_release_path(path);
682
683 if (!BTRFS_I(inode)->generation) {
684 btrfs_info(root->fs_info,
685 "The free space cache file (%llu) is invalid. skip it\n",
686 offset);
687 return 0;
688 }
689
690 if (BTRFS_I(inode)->generation != generation) {
691 btrfs_err(root->fs_info,
692 "free space inode generation (%llu) "
693 "did not match free space cache generation (%llu)",
694 BTRFS_I(inode)->generation, generation);
695 return 0;
696 }
697
698 if (!num_entries)
699 return 0;
700
701 ret = io_ctl_init(&io_ctl, inode, root, 0);
702 if (ret)
703 return ret;
704
705 ret = readahead_cache(inode);
706 if (ret)
707 goto out;
708
709 ret = io_ctl_prepare_pages(&io_ctl, inode, 1);
710 if (ret)
711 goto out;
712
713 ret = io_ctl_check_crc(&io_ctl, 0);
714 if (ret)
715 goto free_cache;
716
717 ret = io_ctl_check_generation(&io_ctl, generation);
718 if (ret)
719 goto free_cache;
720
721 while (num_entries) {
722 e = kmem_cache_zalloc(btrfs_free_space_cachep,
723 GFP_NOFS);
724 if (!e)
725 goto free_cache;
726
727 ret = io_ctl_read_entry(&io_ctl, e, &type);
728 if (ret) {
729 kmem_cache_free(btrfs_free_space_cachep, e);
730 goto free_cache;
731 }
732
733 if (!e->bytes) {
734 kmem_cache_free(btrfs_free_space_cachep, e);
735 goto free_cache;
736 }
737
738 if (type == BTRFS_FREE_SPACE_EXTENT) {
739 spin_lock(&ctl->tree_lock);
740 ret = link_free_space(ctl, e);
741 spin_unlock(&ctl->tree_lock);
742 if (ret) {
743 btrfs_err(root->fs_info,
744 "Duplicate entries in free space cache, dumping");
745 kmem_cache_free(btrfs_free_space_cachep, e);
746 goto free_cache;
747 }
748 } else {
749 ASSERT(num_bitmaps);
750 num_bitmaps--;
751 e->bitmap = kzalloc(PAGE_CACHE_SIZE, GFP_NOFS);
752 if (!e->bitmap) {
753 kmem_cache_free(
754 btrfs_free_space_cachep, e);
755 goto free_cache;
756 }
757 spin_lock(&ctl->tree_lock);
758 ret = link_free_space(ctl, e);
759 ctl->total_bitmaps++;
760 ctl->op->recalc_thresholds(ctl);
761 spin_unlock(&ctl->tree_lock);
762 if (ret) {
763 btrfs_err(root->fs_info,
764 "Duplicate entries in free space cache, dumping");
765 kmem_cache_free(btrfs_free_space_cachep, e);
766 goto free_cache;
767 }
768 list_add_tail(&e->list, &bitmaps);
769 }
770
771 num_entries--;
772 }
773
774 io_ctl_unmap_page(&io_ctl);
775
776 /*
777 * We add the bitmaps at the end of the entries in order that
778 * the bitmap entries are added to the cache.
779 */
780 list_for_each_entry_safe(e, n, &bitmaps, list) {
781 list_del_init(&e->list);
782 ret = io_ctl_read_bitmap(&io_ctl, e);
783 if (ret)
784 goto free_cache;
785 }
786
787 io_ctl_drop_pages(&io_ctl);
788 merge_space_tree(ctl);
789 ret = 1;
790 out:
791 io_ctl_free(&io_ctl);
792 return ret;
793 free_cache:
794 io_ctl_drop_pages(&io_ctl);
795 __btrfs_remove_free_space_cache(ctl);
796 goto out;
797 }
798
799 int load_free_space_cache(struct btrfs_fs_info *fs_info,
800 struct btrfs_block_group_cache *block_group)
801 {
802 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
803 struct btrfs_root *root = fs_info->tree_root;
804 struct inode *inode;
805 struct btrfs_path *path;
806 int ret = 0;
807 bool matched;
808 u64 used = btrfs_block_group_used(&block_group->item);
809
810 /*
811 * If this block group has been marked to be cleared for one reason or
812 * another then we can't trust the on disk cache, so just return.
813 */
814 spin_lock(&block_group->lock);
815 if (block_group->disk_cache_state != BTRFS_DC_WRITTEN) {
816 spin_unlock(&block_group->lock);
817 return 0;
818 }
819 spin_unlock(&block_group->lock);
820
821 path = btrfs_alloc_path();
822 if (!path)
823 return 0;
824 path->search_commit_root = 1;
825 path->skip_locking = 1;
826
827 inode = lookup_free_space_inode(root, block_group, path);
828 if (IS_ERR(inode)) {
829 btrfs_free_path(path);
830 return 0;
831 }
832
833 /* We may have converted the inode and made the cache invalid. */
834 spin_lock(&block_group->lock);
835 if (block_group->disk_cache_state != BTRFS_DC_WRITTEN) {
836 spin_unlock(&block_group->lock);
837 btrfs_free_path(path);
838 goto out;
839 }
840 spin_unlock(&block_group->lock);
841
842 ret = __load_free_space_cache(fs_info->tree_root, inode, ctl,
843 path, block_group->key.objectid);
844 btrfs_free_path(path);
845 if (ret <= 0)
846 goto out;
847
848 spin_lock(&ctl->tree_lock);
849 matched = (ctl->free_space == (block_group->key.offset - used -
850 block_group->bytes_super));
851 spin_unlock(&ctl->tree_lock);
852
853 if (!matched) {
854 __btrfs_remove_free_space_cache(ctl);
855 btrfs_warn(fs_info, "block group %llu has wrong amount of free space",
856 block_group->key.objectid);
857 ret = -1;
858 }
859 out:
860 if (ret < 0) {
861 /* This cache is bogus, make sure it gets cleared */
862 spin_lock(&block_group->lock);
863 block_group->disk_cache_state = BTRFS_DC_CLEAR;
864 spin_unlock(&block_group->lock);
865 ret = 0;
866
867 btrfs_warn(fs_info, "failed to load free space cache for block group %llu, rebuild it now",
868 block_group->key.objectid);
869 }
870
871 iput(inode);
872 return ret;
873 }
874
875 static noinline_for_stack
876 int write_cache_extent_entries(struct io_ctl *io_ctl,
877 struct btrfs_free_space_ctl *ctl,
878 struct btrfs_block_group_cache *block_group,
879 int *entries, int *bitmaps,
880 struct list_head *bitmap_list)
881 {
882 int ret;
883 struct btrfs_free_cluster *cluster = NULL;
884 struct rb_node *node = rb_first(&ctl->free_space_offset);
885
886 /* Get the cluster for this block_group if it exists */
887 if (block_group && !list_empty(&block_group->cluster_list)) {
888 cluster = list_entry(block_group->cluster_list.next,
889 struct btrfs_free_cluster,
890 block_group_list);
891 }
892
893 if (!node && cluster) {
894 node = rb_first(&cluster->root);
895 cluster = NULL;
896 }
897
898 /* Write out the extent entries */
899 while (node) {
900 struct btrfs_free_space *e;
901
902 e = rb_entry(node, struct btrfs_free_space, offset_index);
903 *entries += 1;
904
905 ret = io_ctl_add_entry(io_ctl, e->offset, e->bytes,
906 e->bitmap);
907 if (ret)
908 goto fail;
909
910 if (e->bitmap) {
911 list_add_tail(&e->list, bitmap_list);
912 *bitmaps += 1;
913 }
914 node = rb_next(node);
915 if (!node && cluster) {
916 node = rb_first(&cluster->root);
917 cluster = NULL;
918 }
919 }
920 return 0;
921 fail:
922 return -ENOSPC;
923 }
924
925 static noinline_for_stack int
926 update_cache_item(struct btrfs_trans_handle *trans,
927 struct btrfs_root *root,
928 struct inode *inode,
929 struct btrfs_path *path, u64 offset,
930 int entries, int bitmaps)
931 {
932 struct btrfs_key key;
933 struct btrfs_free_space_header *header;
934 struct extent_buffer *leaf;
935 int ret;
936
937 key.objectid = BTRFS_FREE_SPACE_OBJECTID;
938 key.offset = offset;
939 key.type = 0;
940
941 ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
942 if (ret < 0) {
943 clear_extent_bit(&BTRFS_I(inode)->io_tree, 0, inode->i_size - 1,
944 EXTENT_DIRTY | EXTENT_DELALLOC, 0, 0, NULL,
945 GFP_NOFS);
946 goto fail;
947 }
948 leaf = path->nodes[0];
949 if (ret > 0) {
950 struct btrfs_key found_key;
951 ASSERT(path->slots[0]);
952 path->slots[0]--;
953 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
954 if (found_key.objectid != BTRFS_FREE_SPACE_OBJECTID ||
955 found_key.offset != offset) {
956 clear_extent_bit(&BTRFS_I(inode)->io_tree, 0,
957 inode->i_size - 1,
958 EXTENT_DIRTY | EXTENT_DELALLOC, 0, 0,
959 NULL, GFP_NOFS);
960 btrfs_release_path(path);
961 goto fail;
962 }
963 }
964
965 BTRFS_I(inode)->generation = trans->transid;
966 header = btrfs_item_ptr(leaf, path->slots[0],
967 struct btrfs_free_space_header);
968 btrfs_set_free_space_entries(leaf, header, entries);
969 btrfs_set_free_space_bitmaps(leaf, header, bitmaps);
970 btrfs_set_free_space_generation(leaf, header, trans->transid);
971 btrfs_mark_buffer_dirty(leaf);
972 btrfs_release_path(path);
973
974 return 0;
975
976 fail:
977 return -1;
978 }
979
980 static noinline_for_stack int
981 write_pinned_extent_entries(struct btrfs_root *root,
982 struct btrfs_block_group_cache *block_group,
983 struct io_ctl *io_ctl,
984 int *entries)
985 {
986 u64 start, extent_start, extent_end, len;
987 struct extent_io_tree *unpin = NULL;
988 int ret;
989
990 if (!block_group)
991 return 0;
992
993 /*
994 * We want to add any pinned extents to our free space cache
995 * so we don't leak the space
996 *
997 * We shouldn't have switched the pinned extents yet so this is the
998 * right one
999 */
1000 unpin = root->fs_info->pinned_extents;
1001
1002 start = block_group->key.objectid;
1003
1004 while (start < block_group->key.objectid + block_group->key.offset) {
1005 ret = find_first_extent_bit(unpin, start,
1006 &extent_start, &extent_end,
1007 EXTENT_DIRTY, NULL);
1008 if (ret)
1009 return 0;
1010
1011 /* This pinned extent is out of our range */
1012 if (extent_start >= block_group->key.objectid +
1013 block_group->key.offset)
1014 return 0;
1015
1016 extent_start = max(extent_start, start);
1017 extent_end = min(block_group->key.objectid +
1018 block_group->key.offset, extent_end + 1);
1019 len = extent_end - extent_start;
1020
1021 *entries += 1;
1022 ret = io_ctl_add_entry(io_ctl, extent_start, len, NULL);
1023 if (ret)
1024 return -ENOSPC;
1025
1026 start = extent_end;
1027 }
1028
1029 return 0;
1030 }
1031
1032 static noinline_for_stack int
1033 write_bitmap_entries(struct io_ctl *io_ctl, struct list_head *bitmap_list)
1034 {
1035 struct list_head *pos, *n;
1036 int ret;
1037
1038 /* Write out the bitmaps */
1039 list_for_each_safe(pos, n, bitmap_list) {
1040 struct btrfs_free_space *entry =
1041 list_entry(pos, struct btrfs_free_space, list);
1042
1043 ret = io_ctl_add_bitmap(io_ctl, entry->bitmap);
1044 if (ret)
1045 return -ENOSPC;
1046 list_del_init(&entry->list);
1047 }
1048
1049 return 0;
1050 }
1051
1052 static int flush_dirty_cache(struct inode *inode)
1053 {
1054 int ret;
1055
1056 ret = btrfs_wait_ordered_range(inode, 0, (u64)-1);
1057 if (ret)
1058 clear_extent_bit(&BTRFS_I(inode)->io_tree, 0, inode->i_size - 1,
1059 EXTENT_DIRTY | EXTENT_DELALLOC, 0, 0, NULL,
1060 GFP_NOFS);
1061
1062 return ret;
1063 }
1064
1065 static void noinline_for_stack
1066 cleanup_write_cache_enospc(struct inode *inode,
1067 struct io_ctl *io_ctl,
1068 struct extent_state **cached_state,
1069 struct list_head *bitmap_list)
1070 {
1071 struct list_head *pos, *n;
1072
1073 list_for_each_safe(pos, n, bitmap_list) {
1074 struct btrfs_free_space *entry =
1075 list_entry(pos, struct btrfs_free_space, list);
1076 list_del_init(&entry->list);
1077 }
1078 io_ctl_drop_pages(io_ctl);
1079 unlock_extent_cached(&BTRFS_I(inode)->io_tree, 0,
1080 i_size_read(inode) - 1, cached_state,
1081 GFP_NOFS);
1082 }
1083
1084 /**
1085 * __btrfs_write_out_cache - write out cached info to an inode
1086 * @root - the root the inode belongs to
1087 * @ctl - the free space cache we are going to write out
1088 * @block_group - the block_group for this cache if it belongs to a block_group
1089 * @trans - the trans handle
1090 * @path - the path to use
1091 * @offset - the offset for the key we'll insert
1092 *
1093 * This function writes out a free space cache struct to disk for quick recovery
1094 * on mount. This will return 0 if it was successfull in writing the cache out,
1095 * and -1 if it was not.
1096 */
1097 static int __btrfs_write_out_cache(struct btrfs_root *root, struct inode *inode,
1098 struct btrfs_free_space_ctl *ctl,
1099 struct btrfs_block_group_cache *block_group,
1100 struct btrfs_trans_handle *trans,
1101 struct btrfs_path *path, u64 offset)
1102 {
1103 struct extent_state *cached_state = NULL;
1104 struct io_ctl io_ctl;
1105 LIST_HEAD(bitmap_list);
1106 int entries = 0;
1107 int bitmaps = 0;
1108 int ret;
1109
1110 if (!i_size_read(inode))
1111 return -1;
1112
1113 ret = io_ctl_init(&io_ctl, inode, root, 1);
1114 if (ret)
1115 return -1;
1116
1117 if (block_group && (block_group->flags & BTRFS_BLOCK_GROUP_DATA)) {
1118 down_write(&block_group->data_rwsem);
1119 spin_lock(&block_group->lock);
1120 if (block_group->delalloc_bytes) {
1121 block_group->disk_cache_state = BTRFS_DC_WRITTEN;
1122 spin_unlock(&block_group->lock);
1123 up_write(&block_group->data_rwsem);
1124 BTRFS_I(inode)->generation = 0;
1125 ret = 0;
1126 goto out;
1127 }
1128 spin_unlock(&block_group->lock);
1129 }
1130
1131 /* Lock all pages first so we can lock the extent safely. */
1132 io_ctl_prepare_pages(&io_ctl, inode, 0);
1133
1134 lock_extent_bits(&BTRFS_I(inode)->io_tree, 0, i_size_read(inode) - 1,
1135 0, &cached_state);
1136
1137 io_ctl_set_generation(&io_ctl, trans->transid);
1138
1139 /* Write out the extent entries in the free space cache */
1140 ret = write_cache_extent_entries(&io_ctl, ctl,
1141 block_group, &entries, &bitmaps,
1142 &bitmap_list);
1143 if (ret)
1144 goto out_nospc;
1145
1146 /*
1147 * Some spaces that are freed in the current transaction are pinned,
1148 * they will be added into free space cache after the transaction is
1149 * committed, we shouldn't lose them.
1150 */
1151 ret = write_pinned_extent_entries(root, block_group, &io_ctl, &entries);
1152 if (ret)
1153 goto out_nospc;
1154
1155 /* At last, we write out all the bitmaps. */
1156 ret = write_bitmap_entries(&io_ctl, &bitmap_list);
1157 if (ret)
1158 goto out_nospc;
1159
1160 /* Zero out the rest of the pages just to make sure */
1161 io_ctl_zero_remaining_pages(&io_ctl);
1162
1163 /* Everything is written out, now we dirty the pages in the file. */
1164 ret = btrfs_dirty_pages(root, inode, io_ctl.pages, io_ctl.num_pages,
1165 0, i_size_read(inode), &cached_state);
1166 if (ret)
1167 goto out_nospc;
1168
1169 if (block_group && (block_group->flags & BTRFS_BLOCK_GROUP_DATA))
1170 up_write(&block_group->data_rwsem);
1171 /*
1172 * Release the pages and unlock the extent, we will flush
1173 * them out later
1174 */
1175 io_ctl_drop_pages(&io_ctl);
1176
1177 unlock_extent_cached(&BTRFS_I(inode)->io_tree, 0,
1178 i_size_read(inode) - 1, &cached_state, GFP_NOFS);
1179
1180 /* Flush the dirty pages in the cache file. */
1181 ret = flush_dirty_cache(inode);
1182 if (ret)
1183 goto out;
1184
1185 /* Update the cache item to tell everyone this cache file is valid. */
1186 ret = update_cache_item(trans, root, inode, path, offset,
1187 entries, bitmaps);
1188 out:
1189 io_ctl_free(&io_ctl);
1190 if (ret) {
1191 invalidate_inode_pages2(inode->i_mapping);
1192 BTRFS_I(inode)->generation = 0;
1193 }
1194 btrfs_update_inode(trans, root, inode);
1195 return ret;
1196
1197 out_nospc:
1198 cleanup_write_cache_enospc(inode, &io_ctl, &cached_state, &bitmap_list);
1199
1200 if (block_group && (block_group->flags & BTRFS_BLOCK_GROUP_DATA))
1201 up_write(&block_group->data_rwsem);
1202
1203 goto out;
1204 }
1205
1206 int btrfs_write_out_cache(struct btrfs_root *root,
1207 struct btrfs_trans_handle *trans,
1208 struct btrfs_block_group_cache *block_group,
1209 struct btrfs_path *path)
1210 {
1211 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
1212 struct inode *inode;
1213 int ret = 0;
1214
1215 root = root->fs_info->tree_root;
1216
1217 spin_lock(&block_group->lock);
1218 if (block_group->disk_cache_state < BTRFS_DC_SETUP) {
1219 spin_unlock(&block_group->lock);
1220 return 0;
1221 }
1222
1223 if (block_group->delalloc_bytes) {
1224 block_group->disk_cache_state = BTRFS_DC_WRITTEN;
1225 spin_unlock(&block_group->lock);
1226 return 0;
1227 }
1228 spin_unlock(&block_group->lock);
1229
1230 inode = lookup_free_space_inode(root, block_group, path);
1231 if (IS_ERR(inode))
1232 return 0;
1233
1234 ret = __btrfs_write_out_cache(root, inode, ctl, block_group, trans,
1235 path, block_group->key.objectid);
1236 if (ret) {
1237 spin_lock(&block_group->lock);
1238 block_group->disk_cache_state = BTRFS_DC_ERROR;
1239 spin_unlock(&block_group->lock);
1240 ret = 0;
1241 #ifdef DEBUG
1242 btrfs_err(root->fs_info,
1243 "failed to write free space cache for block group %llu",
1244 block_group->key.objectid);
1245 #endif
1246 }
1247
1248 iput(inode);
1249 return ret;
1250 }
1251
1252 static inline unsigned long offset_to_bit(u64 bitmap_start, u32 unit,
1253 u64 offset)
1254 {
1255 ASSERT(offset >= bitmap_start);
1256 offset -= bitmap_start;
1257 return (unsigned long)(div_u64(offset, unit));
1258 }
1259
1260 static inline unsigned long bytes_to_bits(u64 bytes, u32 unit)
1261 {
1262 return (unsigned long)(div_u64(bytes, unit));
1263 }
1264
1265 static inline u64 offset_to_bitmap(struct btrfs_free_space_ctl *ctl,
1266 u64 offset)
1267 {
1268 u64 bitmap_start;
1269 u64 bytes_per_bitmap;
1270
1271 bytes_per_bitmap = BITS_PER_BITMAP * ctl->unit;
1272 bitmap_start = offset - ctl->start;
1273 bitmap_start = div64_u64(bitmap_start, bytes_per_bitmap);
1274 bitmap_start *= bytes_per_bitmap;
1275 bitmap_start += ctl->start;
1276
1277 return bitmap_start;
1278 }
1279
1280 static int tree_insert_offset(struct rb_root *root, u64 offset,
1281 struct rb_node *node, int bitmap)
1282 {
1283 struct rb_node **p = &root->rb_node;
1284 struct rb_node *parent = NULL;
1285 struct btrfs_free_space *info;
1286
1287 while (*p) {
1288 parent = *p;
1289 info = rb_entry(parent, struct btrfs_free_space, offset_index);
1290
1291 if (offset < info->offset) {
1292 p = &(*p)->rb_left;
1293 } else if (offset > info->offset) {
1294 p = &(*p)->rb_right;
1295 } else {
1296 /*
1297 * we could have a bitmap entry and an extent entry
1298 * share the same offset. If this is the case, we want
1299 * the extent entry to always be found first if we do a
1300 * linear search through the tree, since we want to have
1301 * the quickest allocation time, and allocating from an
1302 * extent is faster than allocating from a bitmap. So
1303 * if we're inserting a bitmap and we find an entry at
1304 * this offset, we want to go right, or after this entry
1305 * logically. If we are inserting an extent and we've
1306 * found a bitmap, we want to go left, or before
1307 * logically.
1308 */
1309 if (bitmap) {
1310 if (info->bitmap) {
1311 WARN_ON_ONCE(1);
1312 return -EEXIST;
1313 }
1314 p = &(*p)->rb_right;
1315 } else {
1316 if (!info->bitmap) {
1317 WARN_ON_ONCE(1);
1318 return -EEXIST;
1319 }
1320 p = &(*p)->rb_left;
1321 }
1322 }
1323 }
1324
1325 rb_link_node(node, parent, p);
1326 rb_insert_color(node, root);
1327
1328 return 0;
1329 }
1330
1331 /*
1332 * searches the tree for the given offset.
1333 *
1334 * fuzzy - If this is set, then we are trying to make an allocation, and we just
1335 * want a section that has at least bytes size and comes at or after the given
1336 * offset.
1337 */
1338 static struct btrfs_free_space *
1339 tree_search_offset(struct btrfs_free_space_ctl *ctl,
1340 u64 offset, int bitmap_only, int fuzzy)
1341 {
1342 struct rb_node *n = ctl->free_space_offset.rb_node;
1343 struct btrfs_free_space *entry, *prev = NULL;
1344
1345 /* find entry that is closest to the 'offset' */
1346 while (1) {
1347 if (!n) {
1348 entry = NULL;
1349 break;
1350 }
1351
1352 entry = rb_entry(n, struct btrfs_free_space, offset_index);
1353 prev = entry;
1354
1355 if (offset < entry->offset)
1356 n = n->rb_left;
1357 else if (offset > entry->offset)
1358 n = n->rb_right;
1359 else
1360 break;
1361 }
1362
1363 if (bitmap_only) {
1364 if (!entry)
1365 return NULL;
1366 if (entry->bitmap)
1367 return entry;
1368
1369 /*
1370 * bitmap entry and extent entry may share same offset,
1371 * in that case, bitmap entry comes after extent entry.
1372 */
1373 n = rb_next(n);
1374 if (!n)
1375 return NULL;
1376 entry = rb_entry(n, struct btrfs_free_space, offset_index);
1377 if (entry->offset != offset)
1378 return NULL;
1379
1380 WARN_ON(!entry->bitmap);
1381 return entry;
1382 } else if (entry) {
1383 if (entry->bitmap) {
1384 /*
1385 * if previous extent entry covers the offset,
1386 * we should return it instead of the bitmap entry
1387 */
1388 n = rb_prev(&entry->offset_index);
1389 if (n) {
1390 prev = rb_entry(n, struct btrfs_free_space,
1391 offset_index);
1392 if (!prev->bitmap &&
1393 prev->offset + prev->bytes > offset)
1394 entry = prev;
1395 }
1396 }
1397 return entry;
1398 }
1399
1400 if (!prev)
1401 return NULL;
1402
1403 /* find last entry before the 'offset' */
1404 entry = prev;
1405 if (entry->offset > offset) {
1406 n = rb_prev(&entry->offset_index);
1407 if (n) {
1408 entry = rb_entry(n, struct btrfs_free_space,
1409 offset_index);
1410 ASSERT(entry->offset <= offset);
1411 } else {
1412 if (fuzzy)
1413 return entry;
1414 else
1415 return NULL;
1416 }
1417 }
1418
1419 if (entry->bitmap) {
1420 n = rb_prev(&entry->offset_index);
1421 if (n) {
1422 prev = rb_entry(n, struct btrfs_free_space,
1423 offset_index);
1424 if (!prev->bitmap &&
1425 prev->offset + prev->bytes > offset)
1426 return prev;
1427 }
1428 if (entry->offset + BITS_PER_BITMAP * ctl->unit > offset)
1429 return entry;
1430 } else if (entry->offset + entry->bytes > offset)
1431 return entry;
1432
1433 if (!fuzzy)
1434 return NULL;
1435
1436 while (1) {
1437 if (entry->bitmap) {
1438 if (entry->offset + BITS_PER_BITMAP *
1439 ctl->unit > offset)
1440 break;
1441 } else {
1442 if (entry->offset + entry->bytes > offset)
1443 break;
1444 }
1445
1446 n = rb_next(&entry->offset_index);
1447 if (!n)
1448 return NULL;
1449 entry = rb_entry(n, struct btrfs_free_space, offset_index);
1450 }
1451 return entry;
1452 }
1453
1454 static inline void
1455 __unlink_free_space(struct btrfs_free_space_ctl *ctl,
1456 struct btrfs_free_space *info)
1457 {
1458 rb_erase(&info->offset_index, &ctl->free_space_offset);
1459 ctl->free_extents--;
1460 }
1461
1462 static void unlink_free_space(struct btrfs_free_space_ctl *ctl,
1463 struct btrfs_free_space *info)
1464 {
1465 __unlink_free_space(ctl, info);
1466 ctl->free_space -= info->bytes;
1467 }
1468
1469 static int link_free_space(struct btrfs_free_space_ctl *ctl,
1470 struct btrfs_free_space *info)
1471 {
1472 int ret = 0;
1473
1474 ASSERT(info->bytes || info->bitmap);
1475 ret = tree_insert_offset(&ctl->free_space_offset, info->offset,
1476 &info->offset_index, (info->bitmap != NULL));
1477 if (ret)
1478 return ret;
1479
1480 ctl->free_space += info->bytes;
1481 ctl->free_extents++;
1482 return ret;
1483 }
1484
1485 static void recalculate_thresholds(struct btrfs_free_space_ctl *ctl)
1486 {
1487 struct btrfs_block_group_cache *block_group = ctl->private;
1488 u64 max_bytes;
1489 u64 bitmap_bytes;
1490 u64 extent_bytes;
1491 u64 size = block_group->key.offset;
1492 u64 bytes_per_bg = BITS_PER_BITMAP * ctl->unit;
1493 int max_bitmaps = div64_u64(size + bytes_per_bg - 1, bytes_per_bg);
1494
1495 max_bitmaps = max(max_bitmaps, 1);
1496
1497 ASSERT(ctl->total_bitmaps <= max_bitmaps);
1498
1499 /*
1500 * The goal is to keep the total amount of memory used per 1gb of space
1501 * at or below 32k, so we need to adjust how much memory we allow to be
1502 * used by extent based free space tracking
1503 */
1504 if (size < 1024 * 1024 * 1024)
1505 max_bytes = MAX_CACHE_BYTES_PER_GIG;
1506 else
1507 max_bytes = MAX_CACHE_BYTES_PER_GIG *
1508 div64_u64(size, 1024 * 1024 * 1024);
1509
1510 /*
1511 * we want to account for 1 more bitmap than what we have so we can make
1512 * sure we don't go over our overall goal of MAX_CACHE_BYTES_PER_GIG as
1513 * we add more bitmaps.
1514 */
1515 bitmap_bytes = (ctl->total_bitmaps + 1) * PAGE_CACHE_SIZE;
1516
1517 if (bitmap_bytes >= max_bytes) {
1518 ctl->extents_thresh = 0;
1519 return;
1520 }
1521
1522 /*
1523 * we want the extent entry threshold to always be at most 1/2 the maxw
1524 * bytes we can have, or whatever is less than that.
1525 */
1526 extent_bytes = max_bytes - bitmap_bytes;
1527 extent_bytes = min_t(u64, extent_bytes, div64_u64(max_bytes, 2));
1528
1529 ctl->extents_thresh =
1530 div64_u64(extent_bytes, (sizeof(struct btrfs_free_space)));
1531 }
1532
1533 static inline void __bitmap_clear_bits(struct btrfs_free_space_ctl *ctl,
1534 struct btrfs_free_space *info,
1535 u64 offset, u64 bytes)
1536 {
1537 unsigned long start, count;
1538
1539 start = offset_to_bit(info->offset, ctl->unit, offset);
1540 count = bytes_to_bits(bytes, ctl->unit);
1541 ASSERT(start + count <= BITS_PER_BITMAP);
1542
1543 bitmap_clear(info->bitmap, start, count);
1544
1545 info->bytes -= bytes;
1546 }
1547
1548 static void bitmap_clear_bits(struct btrfs_free_space_ctl *ctl,
1549 struct btrfs_free_space *info, u64 offset,
1550 u64 bytes)
1551 {
1552 __bitmap_clear_bits(ctl, info, offset, bytes);
1553 ctl->free_space -= bytes;
1554 }
1555
1556 static void bitmap_set_bits(struct btrfs_free_space_ctl *ctl,
1557 struct btrfs_free_space *info, u64 offset,
1558 u64 bytes)
1559 {
1560 unsigned long start, count;
1561
1562 start = offset_to_bit(info->offset, ctl->unit, offset);
1563 count = bytes_to_bits(bytes, ctl->unit);
1564 ASSERT(start + count <= BITS_PER_BITMAP);
1565
1566 bitmap_set(info->bitmap, start, count);
1567
1568 info->bytes += bytes;
1569 ctl->free_space += bytes;
1570 }
1571
1572 /*
1573 * If we can not find suitable extent, we will use bytes to record
1574 * the size of the max extent.
1575 */
1576 static int search_bitmap(struct btrfs_free_space_ctl *ctl,
1577 struct btrfs_free_space *bitmap_info, u64 *offset,
1578 u64 *bytes)
1579 {
1580 unsigned long found_bits = 0;
1581 unsigned long max_bits = 0;
1582 unsigned long bits, i;
1583 unsigned long next_zero;
1584 unsigned long extent_bits;
1585
1586 i = offset_to_bit(bitmap_info->offset, ctl->unit,
1587 max_t(u64, *offset, bitmap_info->offset));
1588 bits = bytes_to_bits(*bytes, ctl->unit);
1589
1590 for_each_set_bit_from(i, bitmap_info->bitmap, BITS_PER_BITMAP) {
1591 next_zero = find_next_zero_bit(bitmap_info->bitmap,
1592 BITS_PER_BITMAP, i);
1593 extent_bits = next_zero - i;
1594 if (extent_bits >= bits) {
1595 found_bits = extent_bits;
1596 break;
1597 } else if (extent_bits > max_bits) {
1598 max_bits = extent_bits;
1599 }
1600 i = next_zero;
1601 }
1602
1603 if (found_bits) {
1604 *offset = (u64)(i * ctl->unit) + bitmap_info->offset;
1605 *bytes = (u64)(found_bits) * ctl->unit;
1606 return 0;
1607 }
1608
1609 *bytes = (u64)(max_bits) * ctl->unit;
1610 return -1;
1611 }
1612
1613 /* Cache the size of the max extent in bytes */
1614 static struct btrfs_free_space *
1615 find_free_space(struct btrfs_free_space_ctl *ctl, u64 *offset, u64 *bytes,
1616 unsigned long align, u64 *max_extent_size)
1617 {
1618 struct btrfs_free_space *entry;
1619 struct rb_node *node;
1620 u64 tmp;
1621 u64 align_off;
1622 int ret;
1623
1624 if (!ctl->free_space_offset.rb_node)
1625 goto out;
1626
1627 entry = tree_search_offset(ctl, offset_to_bitmap(ctl, *offset), 0, 1);
1628 if (!entry)
1629 goto out;
1630
1631 for (node = &entry->offset_index; node; node = rb_next(node)) {
1632 entry = rb_entry(node, struct btrfs_free_space, offset_index);
1633 if (entry->bytes < *bytes) {
1634 if (entry->bytes > *max_extent_size)
1635 *max_extent_size = entry->bytes;
1636 continue;
1637 }
1638
1639 /* make sure the space returned is big enough
1640 * to match our requested alignment
1641 */
1642 if (*bytes >= align) {
1643 tmp = entry->offset - ctl->start + align - 1;
1644 do_div(tmp, align);
1645 tmp = tmp * align + ctl->start;
1646 align_off = tmp - entry->offset;
1647 } else {
1648 align_off = 0;
1649 tmp = entry->offset;
1650 }
1651
1652 if (entry->bytes < *bytes + align_off) {
1653 if (entry->bytes > *max_extent_size)
1654 *max_extent_size = entry->bytes;
1655 continue;
1656 }
1657
1658 if (entry->bitmap) {
1659 u64 size = *bytes;
1660
1661 ret = search_bitmap(ctl, entry, &tmp, &size);
1662 if (!ret) {
1663 *offset = tmp;
1664 *bytes = size;
1665 return entry;
1666 } else if (size > *max_extent_size) {
1667 *max_extent_size = size;
1668 }
1669 continue;
1670 }
1671
1672 *offset = tmp;
1673 *bytes = entry->bytes - align_off;
1674 return entry;
1675 }
1676 out:
1677 return NULL;
1678 }
1679
1680 static void add_new_bitmap(struct btrfs_free_space_ctl *ctl,
1681 struct btrfs_free_space *info, u64 offset)
1682 {
1683 info->offset = offset_to_bitmap(ctl, offset);
1684 info->bytes = 0;
1685 INIT_LIST_HEAD(&info->list);
1686 link_free_space(ctl, info);
1687 ctl->total_bitmaps++;
1688
1689 ctl->op->recalc_thresholds(ctl);
1690 }
1691
1692 static void free_bitmap(struct btrfs_free_space_ctl *ctl,
1693 struct btrfs_free_space *bitmap_info)
1694 {
1695 unlink_free_space(ctl, bitmap_info);
1696 kfree(bitmap_info->bitmap);
1697 kmem_cache_free(btrfs_free_space_cachep, bitmap_info);
1698 ctl->total_bitmaps--;
1699 ctl->op->recalc_thresholds(ctl);
1700 }
1701
1702 static noinline int remove_from_bitmap(struct btrfs_free_space_ctl *ctl,
1703 struct btrfs_free_space *bitmap_info,
1704 u64 *offset, u64 *bytes)
1705 {
1706 u64 end;
1707 u64 search_start, search_bytes;
1708 int ret;
1709
1710 again:
1711 end = bitmap_info->offset + (u64)(BITS_PER_BITMAP * ctl->unit) - 1;
1712
1713 /*
1714 * We need to search for bits in this bitmap. We could only cover some
1715 * of the extent in this bitmap thanks to how we add space, so we need
1716 * to search for as much as it as we can and clear that amount, and then
1717 * go searching for the next bit.
1718 */
1719 search_start = *offset;
1720 search_bytes = ctl->unit;
1721 search_bytes = min(search_bytes, end - search_start + 1);
1722 ret = search_bitmap(ctl, bitmap_info, &search_start, &search_bytes);
1723 if (ret < 0 || search_start != *offset)
1724 return -EINVAL;
1725
1726 /* We may have found more bits than what we need */
1727 search_bytes = min(search_bytes, *bytes);
1728
1729 /* Cannot clear past the end of the bitmap */
1730 search_bytes = min(search_bytes, end - search_start + 1);
1731
1732 bitmap_clear_bits(ctl, bitmap_info, search_start, search_bytes);
1733 *offset += search_bytes;
1734 *bytes -= search_bytes;
1735
1736 if (*bytes) {
1737 struct rb_node *next = rb_next(&bitmap_info->offset_index);
1738 if (!bitmap_info->bytes)
1739 free_bitmap(ctl, bitmap_info);
1740
1741 /*
1742 * no entry after this bitmap, but we still have bytes to
1743 * remove, so something has gone wrong.
1744 */
1745 if (!next)
1746 return -EINVAL;
1747
1748 bitmap_info = rb_entry(next, struct btrfs_free_space,
1749 offset_index);
1750
1751 /*
1752 * if the next entry isn't a bitmap we need to return to let the
1753 * extent stuff do its work.
1754 */
1755 if (!bitmap_info->bitmap)
1756 return -EAGAIN;
1757
1758 /*
1759 * Ok the next item is a bitmap, but it may not actually hold
1760 * the information for the rest of this free space stuff, so
1761 * look for it, and if we don't find it return so we can try
1762 * everything over again.
1763 */
1764 search_start = *offset;
1765 search_bytes = ctl->unit;
1766 ret = search_bitmap(ctl, bitmap_info, &search_start,
1767 &search_bytes);
1768 if (ret < 0 || search_start != *offset)
1769 return -EAGAIN;
1770
1771 goto again;
1772 } else if (!bitmap_info->bytes)
1773 free_bitmap(ctl, bitmap_info);
1774
1775 return 0;
1776 }
1777
1778 static u64 add_bytes_to_bitmap(struct btrfs_free_space_ctl *ctl,
1779 struct btrfs_free_space *info, u64 offset,
1780 u64 bytes)
1781 {
1782 u64 bytes_to_set = 0;
1783 u64 end;
1784
1785 end = info->offset + (u64)(BITS_PER_BITMAP * ctl->unit);
1786
1787 bytes_to_set = min(end - offset, bytes);
1788
1789 bitmap_set_bits(ctl, info, offset, bytes_to_set);
1790
1791 return bytes_to_set;
1792
1793 }
1794
1795 static bool use_bitmap(struct btrfs_free_space_ctl *ctl,
1796 struct btrfs_free_space *info)
1797 {
1798 struct btrfs_block_group_cache *block_group = ctl->private;
1799
1800 /*
1801 * If we are below the extents threshold then we can add this as an
1802 * extent, and don't have to deal with the bitmap
1803 */
1804 if (ctl->free_extents < ctl->extents_thresh) {
1805 /*
1806 * If this block group has some small extents we don't want to
1807 * use up all of our free slots in the cache with them, we want
1808 * to reserve them to larger extents, however if we have plent
1809 * of cache left then go ahead an dadd them, no sense in adding
1810 * the overhead of a bitmap if we don't have to.
1811 */
1812 if (info->bytes <= block_group->sectorsize * 4) {
1813 if (ctl->free_extents * 2 <= ctl->extents_thresh)
1814 return false;
1815 } else {
1816 return false;
1817 }
1818 }
1819
1820 /*
1821 * The original block groups from mkfs can be really small, like 8
1822 * megabytes, so don't bother with a bitmap for those entries. However
1823 * some block groups can be smaller than what a bitmap would cover but
1824 * are still large enough that they could overflow the 32k memory limit,
1825 * so allow those block groups to still be allowed to have a bitmap
1826 * entry.
1827 */
1828 if (((BITS_PER_BITMAP * ctl->unit) >> 1) > block_group->key.offset)
1829 return false;
1830
1831 return true;
1832 }
1833
1834 static struct btrfs_free_space_op free_space_op = {
1835 .recalc_thresholds = recalculate_thresholds,
1836 .use_bitmap = use_bitmap,
1837 };
1838
1839 static int insert_into_bitmap(struct btrfs_free_space_ctl *ctl,
1840 struct btrfs_free_space *info)
1841 {
1842 struct btrfs_free_space *bitmap_info;
1843 struct btrfs_block_group_cache *block_group = NULL;
1844 int added = 0;
1845 u64 bytes, offset, bytes_added;
1846 int ret;
1847
1848 bytes = info->bytes;
1849 offset = info->offset;
1850
1851 if (!ctl->op->use_bitmap(ctl, info))
1852 return 0;
1853
1854 if (ctl->op == &free_space_op)
1855 block_group = ctl->private;
1856 again:
1857 /*
1858 * Since we link bitmaps right into the cluster we need to see if we
1859 * have a cluster here, and if so and it has our bitmap we need to add
1860 * the free space to that bitmap.
1861 */
1862 if (block_group && !list_empty(&block_group->cluster_list)) {
1863 struct btrfs_free_cluster *cluster;
1864 struct rb_node *node;
1865 struct btrfs_free_space *entry;
1866
1867 cluster = list_entry(block_group->cluster_list.next,
1868 struct btrfs_free_cluster,
1869 block_group_list);
1870 spin_lock(&cluster->lock);
1871 node = rb_first(&cluster->root);
1872 if (!node) {
1873 spin_unlock(&cluster->lock);
1874 goto no_cluster_bitmap;
1875 }
1876
1877 entry = rb_entry(node, struct btrfs_free_space, offset_index);
1878 if (!entry->bitmap) {
1879 spin_unlock(&cluster->lock);
1880 goto no_cluster_bitmap;
1881 }
1882
1883 if (entry->offset == offset_to_bitmap(ctl, offset)) {
1884 bytes_added = add_bytes_to_bitmap(ctl, entry,
1885 offset, bytes);
1886 bytes -= bytes_added;
1887 offset += bytes_added;
1888 }
1889 spin_unlock(&cluster->lock);
1890 if (!bytes) {
1891 ret = 1;
1892 goto out;
1893 }
1894 }
1895
1896 no_cluster_bitmap:
1897 bitmap_info = tree_search_offset(ctl, offset_to_bitmap(ctl, offset),
1898 1, 0);
1899 if (!bitmap_info) {
1900 ASSERT(added == 0);
1901 goto new_bitmap;
1902 }
1903
1904 bytes_added = add_bytes_to_bitmap(ctl, bitmap_info, offset, bytes);
1905 bytes -= bytes_added;
1906 offset += bytes_added;
1907 added = 0;
1908
1909 if (!bytes) {
1910 ret = 1;
1911 goto out;
1912 } else
1913 goto again;
1914
1915 new_bitmap:
1916 if (info && info->bitmap) {
1917 add_new_bitmap(ctl, info, offset);
1918 added = 1;
1919 info = NULL;
1920 goto again;
1921 } else {
1922 spin_unlock(&ctl->tree_lock);
1923
1924 /* no pre-allocated info, allocate a new one */
1925 if (!info) {
1926 info = kmem_cache_zalloc(btrfs_free_space_cachep,
1927 GFP_NOFS);
1928 if (!info) {
1929 spin_lock(&ctl->tree_lock);
1930 ret = -ENOMEM;
1931 goto out;
1932 }
1933 }
1934
1935 /* allocate the bitmap */
1936 info->bitmap = kzalloc(PAGE_CACHE_SIZE, GFP_NOFS);
1937 spin_lock(&ctl->tree_lock);
1938 if (!info->bitmap) {
1939 ret = -ENOMEM;
1940 goto out;
1941 }
1942 goto again;
1943 }
1944
1945 out:
1946 if (info) {
1947 if (info->bitmap)
1948 kfree(info->bitmap);
1949 kmem_cache_free(btrfs_free_space_cachep, info);
1950 }
1951
1952 return ret;
1953 }
1954
1955 static bool try_merge_free_space(struct btrfs_free_space_ctl *ctl,
1956 struct btrfs_free_space *info, bool update_stat)
1957 {
1958 struct btrfs_free_space *left_info;
1959 struct btrfs_free_space *right_info;
1960 bool merged = false;
1961 u64 offset = info->offset;
1962 u64 bytes = info->bytes;
1963
1964 /*
1965 * first we want to see if there is free space adjacent to the range we
1966 * are adding, if there is remove that struct and add a new one to
1967 * cover the entire range
1968 */
1969 right_info = tree_search_offset(ctl, offset + bytes, 0, 0);
1970 if (right_info && rb_prev(&right_info->offset_index))
1971 left_info = rb_entry(rb_prev(&right_info->offset_index),
1972 struct btrfs_free_space, offset_index);
1973 else
1974 left_info = tree_search_offset(ctl, offset - 1, 0, 0);
1975
1976 if (right_info && !right_info->bitmap) {
1977 if (update_stat)
1978 unlink_free_space(ctl, right_info);
1979 else
1980 __unlink_free_space(ctl, right_info);
1981 info->bytes += right_info->bytes;
1982 kmem_cache_free(btrfs_free_space_cachep, right_info);
1983 merged = true;
1984 }
1985
1986 if (left_info && !left_info->bitmap &&
1987 left_info->offset + left_info->bytes == offset) {
1988 if (update_stat)
1989 unlink_free_space(ctl, left_info);
1990 else
1991 __unlink_free_space(ctl, left_info);
1992 info->offset = left_info->offset;
1993 info->bytes += left_info->bytes;
1994 kmem_cache_free(btrfs_free_space_cachep, left_info);
1995 merged = true;
1996 }
1997
1998 return merged;
1999 }
2000
2001 int __btrfs_add_free_space(struct btrfs_free_space_ctl *ctl,
2002 u64 offset, u64 bytes)
2003 {
2004 struct btrfs_free_space *info;
2005 int ret = 0;
2006
2007 info = kmem_cache_zalloc(btrfs_free_space_cachep, GFP_NOFS);
2008 if (!info)
2009 return -ENOMEM;
2010
2011 info->offset = offset;
2012 info->bytes = bytes;
2013
2014 spin_lock(&ctl->tree_lock);
2015
2016 if (try_merge_free_space(ctl, info, true))
2017 goto link;
2018
2019 /*
2020 * There was no extent directly to the left or right of this new
2021 * extent then we know we're going to have to allocate a new extent, so
2022 * before we do that see if we need to drop this into a bitmap
2023 */
2024 ret = insert_into_bitmap(ctl, info);
2025 if (ret < 0) {
2026 goto out;
2027 } else if (ret) {
2028 ret = 0;
2029 goto out;
2030 }
2031 link:
2032 ret = link_free_space(ctl, info);
2033 if (ret)
2034 kmem_cache_free(btrfs_free_space_cachep, info);
2035 out:
2036 spin_unlock(&ctl->tree_lock);
2037
2038 if (ret) {
2039 printk(KERN_CRIT "BTRFS: unable to add free space :%d\n", ret);
2040 ASSERT(ret != -EEXIST);
2041 }
2042
2043 return ret;
2044 }
2045
2046 int btrfs_remove_free_space(struct btrfs_block_group_cache *block_group,
2047 u64 offset, u64 bytes)
2048 {
2049 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2050 struct btrfs_free_space *info;
2051 int ret;
2052 bool re_search = false;
2053
2054 spin_lock(&ctl->tree_lock);
2055
2056 again:
2057 ret = 0;
2058 if (!bytes)
2059 goto out_lock;
2060
2061 info = tree_search_offset(ctl, offset, 0, 0);
2062 if (!info) {
2063 /*
2064 * oops didn't find an extent that matched the space we wanted
2065 * to remove, look for a bitmap instead
2066 */
2067 info = tree_search_offset(ctl, offset_to_bitmap(ctl, offset),
2068 1, 0);
2069 if (!info) {
2070 /*
2071 * If we found a partial bit of our free space in a
2072 * bitmap but then couldn't find the other part this may
2073 * be a problem, so WARN about it.
2074 */
2075 WARN_ON(re_search);
2076 goto out_lock;
2077 }
2078 }
2079
2080 re_search = false;
2081 if (!info->bitmap) {
2082 unlink_free_space(ctl, info);
2083 if (offset == info->offset) {
2084 u64 to_free = min(bytes, info->bytes);
2085
2086 info->bytes -= to_free;
2087 info->offset += to_free;
2088 if (info->bytes) {
2089 ret = link_free_space(ctl, info);
2090 WARN_ON(ret);
2091 } else {
2092 kmem_cache_free(btrfs_free_space_cachep, info);
2093 }
2094
2095 offset += to_free;
2096 bytes -= to_free;
2097 goto again;
2098 } else {
2099 u64 old_end = info->bytes + info->offset;
2100
2101 info->bytes = offset - info->offset;
2102 ret = link_free_space(ctl, info);
2103 WARN_ON(ret);
2104 if (ret)
2105 goto out_lock;
2106
2107 /* Not enough bytes in this entry to satisfy us */
2108 if (old_end < offset + bytes) {
2109 bytes -= old_end - offset;
2110 offset = old_end;
2111 goto again;
2112 } else if (old_end == offset + bytes) {
2113 /* all done */
2114 goto out_lock;
2115 }
2116 spin_unlock(&ctl->tree_lock);
2117
2118 ret = btrfs_add_free_space(block_group, offset + bytes,
2119 old_end - (offset + bytes));
2120 WARN_ON(ret);
2121 goto out;
2122 }
2123 }
2124
2125 ret = remove_from_bitmap(ctl, info, &offset, &bytes);
2126 if (ret == -EAGAIN) {
2127 re_search = true;
2128 goto again;
2129 }
2130 out_lock:
2131 spin_unlock(&ctl->tree_lock);
2132 out:
2133 return ret;
2134 }
2135
2136 void btrfs_dump_free_space(struct btrfs_block_group_cache *block_group,
2137 u64 bytes)
2138 {
2139 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2140 struct btrfs_free_space *info;
2141 struct rb_node *n;
2142 int count = 0;
2143
2144 for (n = rb_first(&ctl->free_space_offset); n; n = rb_next(n)) {
2145 info = rb_entry(n, struct btrfs_free_space, offset_index);
2146 if (info->bytes >= bytes && !block_group->ro)
2147 count++;
2148 btrfs_crit(block_group->fs_info,
2149 "entry offset %llu, bytes %llu, bitmap %s",
2150 info->offset, info->bytes,
2151 (info->bitmap) ? "yes" : "no");
2152 }
2153 btrfs_info(block_group->fs_info, "block group has cluster?: %s",
2154 list_empty(&block_group->cluster_list) ? "no" : "yes");
2155 btrfs_info(block_group->fs_info,
2156 "%d blocks of free space at or bigger than bytes is", count);
2157 }
2158
2159 void btrfs_init_free_space_ctl(struct btrfs_block_group_cache *block_group)
2160 {
2161 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2162
2163 spin_lock_init(&ctl->tree_lock);
2164 ctl->unit = block_group->sectorsize;
2165 ctl->start = block_group->key.objectid;
2166 ctl->private = block_group;
2167 ctl->op = &free_space_op;
2168
2169 /*
2170 * we only want to have 32k of ram per block group for keeping
2171 * track of free space, and if we pass 1/2 of that we want to
2172 * start converting things over to using bitmaps
2173 */
2174 ctl->extents_thresh = ((1024 * 32) / 2) /
2175 sizeof(struct btrfs_free_space);
2176 }
2177
2178 /*
2179 * for a given cluster, put all of its extents back into the free
2180 * space cache. If the block group passed doesn't match the block group
2181 * pointed to by the cluster, someone else raced in and freed the
2182 * cluster already. In that case, we just return without changing anything
2183 */
2184 static int
2185 __btrfs_return_cluster_to_free_space(
2186 struct btrfs_block_group_cache *block_group,
2187 struct btrfs_free_cluster *cluster)
2188 {
2189 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2190 struct btrfs_free_space *entry;
2191 struct rb_node *node;
2192
2193 spin_lock(&cluster->lock);
2194 if (cluster->block_group != block_group)
2195 goto out;
2196
2197 cluster->block_group = NULL;
2198 cluster->window_start = 0;
2199 list_del_init(&cluster->block_group_list);
2200
2201 node = rb_first(&cluster->root);
2202 while (node) {
2203 bool bitmap;
2204
2205 entry = rb_entry(node, struct btrfs_free_space, offset_index);
2206 node = rb_next(&entry->offset_index);
2207 rb_erase(&entry->offset_index, &cluster->root);
2208
2209 bitmap = (entry->bitmap != NULL);
2210 if (!bitmap)
2211 try_merge_free_space(ctl, entry, false);
2212 tree_insert_offset(&ctl->free_space_offset,
2213 entry->offset, &entry->offset_index, bitmap);
2214 }
2215 cluster->root = RB_ROOT;
2216
2217 out:
2218 spin_unlock(&cluster->lock);
2219 btrfs_put_block_group(block_group);
2220 return 0;
2221 }
2222
2223 static void __btrfs_remove_free_space_cache_locked(
2224 struct btrfs_free_space_ctl *ctl)
2225 {
2226 struct btrfs_free_space *info;
2227 struct rb_node *node;
2228
2229 while ((node = rb_last(&ctl->free_space_offset)) != NULL) {
2230 info = rb_entry(node, struct btrfs_free_space, offset_index);
2231 if (!info->bitmap) {
2232 unlink_free_space(ctl, info);
2233 kmem_cache_free(btrfs_free_space_cachep, info);
2234 } else {
2235 free_bitmap(ctl, info);
2236 }
2237 if (need_resched()) {
2238 spin_unlock(&ctl->tree_lock);
2239 cond_resched();
2240 spin_lock(&ctl->tree_lock);
2241 }
2242 }
2243 }
2244
2245 void __btrfs_remove_free_space_cache(struct btrfs_free_space_ctl *ctl)
2246 {
2247 spin_lock(&ctl->tree_lock);
2248 __btrfs_remove_free_space_cache_locked(ctl);
2249 spin_unlock(&ctl->tree_lock);
2250 }
2251
2252 void btrfs_remove_free_space_cache(struct btrfs_block_group_cache *block_group)
2253 {
2254 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2255 struct btrfs_free_cluster *cluster;
2256 struct list_head *head;
2257
2258 spin_lock(&ctl->tree_lock);
2259 while ((head = block_group->cluster_list.next) !=
2260 &block_group->cluster_list) {
2261 cluster = list_entry(head, struct btrfs_free_cluster,
2262 block_group_list);
2263
2264 WARN_ON(cluster->block_group != block_group);
2265 __btrfs_return_cluster_to_free_space(block_group, cluster);
2266 if (need_resched()) {
2267 spin_unlock(&ctl->tree_lock);
2268 cond_resched();
2269 spin_lock(&ctl->tree_lock);
2270 }
2271 }
2272 __btrfs_remove_free_space_cache_locked(ctl);
2273 spin_unlock(&ctl->tree_lock);
2274
2275 }
2276
2277 u64 btrfs_find_space_for_alloc(struct btrfs_block_group_cache *block_group,
2278 u64 offset, u64 bytes, u64 empty_size,
2279 u64 *max_extent_size)
2280 {
2281 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2282 struct btrfs_free_space *entry = NULL;
2283 u64 bytes_search = bytes + empty_size;
2284 u64 ret = 0;
2285 u64 align_gap = 0;
2286 u64 align_gap_len = 0;
2287
2288 spin_lock(&ctl->tree_lock);
2289 entry = find_free_space(ctl, &offset, &bytes_search,
2290 block_group->full_stripe_len, max_extent_size);
2291 if (!entry)
2292 goto out;
2293
2294 ret = offset;
2295 if (entry->bitmap) {
2296 bitmap_clear_bits(ctl, entry, offset, bytes);
2297 if (!entry->bytes)
2298 free_bitmap(ctl, entry);
2299 } else {
2300 unlink_free_space(ctl, entry);
2301 align_gap_len = offset - entry->offset;
2302 align_gap = entry->offset;
2303
2304 entry->offset = offset + bytes;
2305 WARN_ON(entry->bytes < bytes + align_gap_len);
2306
2307 entry->bytes -= bytes + align_gap_len;
2308 if (!entry->bytes)
2309 kmem_cache_free(btrfs_free_space_cachep, entry);
2310 else
2311 link_free_space(ctl, entry);
2312 }
2313 out:
2314 spin_unlock(&ctl->tree_lock);
2315
2316 if (align_gap_len)
2317 __btrfs_add_free_space(ctl, align_gap, align_gap_len);
2318 return ret;
2319 }
2320
2321 /*
2322 * given a cluster, put all of its extents back into the free space
2323 * cache. If a block group is passed, this function will only free
2324 * a cluster that belongs to the passed block group.
2325 *
2326 * Otherwise, it'll get a reference on the block group pointed to by the
2327 * cluster and remove the cluster from it.
2328 */
2329 int btrfs_return_cluster_to_free_space(
2330 struct btrfs_block_group_cache *block_group,
2331 struct btrfs_free_cluster *cluster)
2332 {
2333 struct btrfs_free_space_ctl *ctl;
2334 int ret;
2335
2336 /* first, get a safe pointer to the block group */
2337 spin_lock(&cluster->lock);
2338 if (!block_group) {
2339 block_group = cluster->block_group;
2340 if (!block_group) {
2341 spin_unlock(&cluster->lock);
2342 return 0;
2343 }
2344 } else if (cluster->block_group != block_group) {
2345 /* someone else has already freed it don't redo their work */
2346 spin_unlock(&cluster->lock);
2347 return 0;
2348 }
2349 atomic_inc(&block_group->count);
2350 spin_unlock(&cluster->lock);
2351
2352 ctl = block_group->free_space_ctl;
2353
2354 /* now return any extents the cluster had on it */
2355 spin_lock(&ctl->tree_lock);
2356 ret = __btrfs_return_cluster_to_free_space(block_group, cluster);
2357 spin_unlock(&ctl->tree_lock);
2358
2359 /* finally drop our ref */
2360 btrfs_put_block_group(block_group);
2361 return ret;
2362 }
2363
2364 static u64 btrfs_alloc_from_bitmap(struct btrfs_block_group_cache *block_group,
2365 struct btrfs_free_cluster *cluster,
2366 struct btrfs_free_space *entry,
2367 u64 bytes, u64 min_start,
2368 u64 *max_extent_size)
2369 {
2370 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2371 int err;
2372 u64 search_start = cluster->window_start;
2373 u64 search_bytes = bytes;
2374 u64 ret = 0;
2375
2376 search_start = min_start;
2377 search_bytes = bytes;
2378
2379 err = search_bitmap(ctl, entry, &search_start, &search_bytes);
2380 if (err) {
2381 if (search_bytes > *max_extent_size)
2382 *max_extent_size = search_bytes;
2383 return 0;
2384 }
2385
2386 ret = search_start;
2387 __bitmap_clear_bits(ctl, entry, ret, bytes);
2388
2389 return ret;
2390 }
2391
2392 /*
2393 * given a cluster, try to allocate 'bytes' from it, returns 0
2394 * if it couldn't find anything suitably large, or a logical disk offset
2395 * if things worked out
2396 */
2397 u64 btrfs_alloc_from_cluster(struct btrfs_block_group_cache *block_group,
2398 struct btrfs_free_cluster *cluster, u64 bytes,
2399 u64 min_start, u64 *max_extent_size)
2400 {
2401 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2402 struct btrfs_free_space *entry = NULL;
2403 struct rb_node *node;
2404 u64 ret = 0;
2405
2406 spin_lock(&cluster->lock);
2407 if (bytes > cluster->max_size)
2408 goto out;
2409
2410 if (cluster->block_group != block_group)
2411 goto out;
2412
2413 node = rb_first(&cluster->root);
2414 if (!node)
2415 goto out;
2416
2417 entry = rb_entry(node, struct btrfs_free_space, offset_index);
2418 while (1) {
2419 if (entry->bytes < bytes && entry->bytes > *max_extent_size)
2420 *max_extent_size = entry->bytes;
2421
2422 if (entry->bytes < bytes ||
2423 (!entry->bitmap && entry->offset < min_start)) {
2424 node = rb_next(&entry->offset_index);
2425 if (!node)
2426 break;
2427 entry = rb_entry(node, struct btrfs_free_space,
2428 offset_index);
2429 continue;
2430 }
2431
2432 if (entry->bitmap) {
2433 ret = btrfs_alloc_from_bitmap(block_group,
2434 cluster, entry, bytes,
2435 cluster->window_start,
2436 max_extent_size);
2437 if (ret == 0) {
2438 node = rb_next(&entry->offset_index);
2439 if (!node)
2440 break;
2441 entry = rb_entry(node, struct btrfs_free_space,
2442 offset_index);
2443 continue;
2444 }
2445 cluster->window_start += bytes;
2446 } else {
2447 ret = entry->offset;
2448
2449 entry->offset += bytes;
2450 entry->bytes -= bytes;
2451 }
2452
2453 if (entry->bytes == 0)
2454 rb_erase(&entry->offset_index, &cluster->root);
2455 break;
2456 }
2457 out:
2458 spin_unlock(&cluster->lock);
2459
2460 if (!ret)
2461 return 0;
2462
2463 spin_lock(&ctl->tree_lock);
2464
2465 ctl->free_space -= bytes;
2466 if (entry->bytes == 0) {
2467 ctl->free_extents--;
2468 if (entry->bitmap) {
2469 kfree(entry->bitmap);
2470 ctl->total_bitmaps--;
2471 ctl->op->recalc_thresholds(ctl);
2472 }
2473 kmem_cache_free(btrfs_free_space_cachep, entry);
2474 }
2475
2476 spin_unlock(&ctl->tree_lock);
2477
2478 return ret;
2479 }
2480
2481 static int btrfs_bitmap_cluster(struct btrfs_block_group_cache *block_group,
2482 struct btrfs_free_space *entry,
2483 struct btrfs_free_cluster *cluster,
2484 u64 offset, u64 bytes,
2485 u64 cont1_bytes, u64 min_bytes)
2486 {
2487 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2488 unsigned long next_zero;
2489 unsigned long i;
2490 unsigned long want_bits;
2491 unsigned long min_bits;
2492 unsigned long found_bits;
2493 unsigned long start = 0;
2494 unsigned long total_found = 0;
2495 int ret;
2496
2497 i = offset_to_bit(entry->offset, ctl->unit,
2498 max_t(u64, offset, entry->offset));
2499 want_bits = bytes_to_bits(bytes, ctl->unit);
2500 min_bits = bytes_to_bits(min_bytes, ctl->unit);
2501
2502 again:
2503 found_bits = 0;
2504 for_each_set_bit_from(i, entry->bitmap, BITS_PER_BITMAP) {
2505 next_zero = find_next_zero_bit(entry->bitmap,
2506 BITS_PER_BITMAP, i);
2507 if (next_zero - i >= min_bits) {
2508 found_bits = next_zero - i;
2509 break;
2510 }
2511 i = next_zero;
2512 }
2513
2514 if (!found_bits)
2515 return -ENOSPC;
2516
2517 if (!total_found) {
2518 start = i;
2519 cluster->max_size = 0;
2520 }
2521
2522 total_found += found_bits;
2523
2524 if (cluster->max_size < found_bits * ctl->unit)
2525 cluster->max_size = found_bits * ctl->unit;
2526
2527 if (total_found < want_bits || cluster->max_size < cont1_bytes) {
2528 i = next_zero + 1;
2529 goto again;
2530 }
2531
2532 cluster->window_start = start * ctl->unit + entry->offset;
2533 rb_erase(&entry->offset_index, &ctl->free_space_offset);
2534 ret = tree_insert_offset(&cluster->root, entry->offset,
2535 &entry->offset_index, 1);
2536 ASSERT(!ret); /* -EEXIST; Logic error */
2537
2538 trace_btrfs_setup_cluster(block_group, cluster,
2539 total_found * ctl->unit, 1);
2540 return 0;
2541 }
2542
2543 /*
2544 * This searches the block group for just extents to fill the cluster with.
2545 * Try to find a cluster with at least bytes total bytes, at least one
2546 * extent of cont1_bytes, and other clusters of at least min_bytes.
2547 */
2548 static noinline int
2549 setup_cluster_no_bitmap(struct btrfs_block_group_cache *block_group,
2550 struct btrfs_free_cluster *cluster,
2551 struct list_head *bitmaps, u64 offset, u64 bytes,
2552 u64 cont1_bytes, u64 min_bytes)
2553 {
2554 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2555 struct btrfs_free_space *first = NULL;
2556 struct btrfs_free_space *entry = NULL;
2557 struct btrfs_free_space *last;
2558 struct rb_node *node;
2559 u64 window_free;
2560 u64 max_extent;
2561 u64 total_size = 0;
2562
2563 entry = tree_search_offset(ctl, offset, 0, 1);
2564 if (!entry)
2565 return -ENOSPC;
2566
2567 /*
2568 * We don't want bitmaps, so just move along until we find a normal
2569 * extent entry.
2570 */
2571 while (entry->bitmap || entry->bytes < min_bytes) {
2572 if (entry->bitmap && list_empty(&entry->list))
2573 list_add_tail(&entry->list, bitmaps);
2574 node = rb_next(&entry->offset_index);
2575 if (!node)
2576 return -ENOSPC;
2577 entry = rb_entry(node, struct btrfs_free_space, offset_index);
2578 }
2579
2580 window_free = entry->bytes;
2581 max_extent = entry->bytes;
2582 first = entry;
2583 last = entry;
2584
2585 for (node = rb_next(&entry->offset_index); node;
2586 node = rb_next(&entry->offset_index)) {
2587 entry = rb_entry(node, struct btrfs_free_space, offset_index);
2588
2589 if (entry->bitmap) {
2590 if (list_empty(&entry->list))
2591 list_add_tail(&entry->list, bitmaps);
2592 continue;
2593 }
2594
2595 if (entry->bytes < min_bytes)
2596 continue;
2597
2598 last = entry;
2599 window_free += entry->bytes;
2600 if (entry->bytes > max_extent)
2601 max_extent = entry->bytes;
2602 }
2603
2604 if (window_free < bytes || max_extent < cont1_bytes)
2605 return -ENOSPC;
2606
2607 cluster->window_start = first->offset;
2608
2609 node = &first->offset_index;
2610
2611 /*
2612 * now we've found our entries, pull them out of the free space
2613 * cache and put them into the cluster rbtree
2614 */
2615 do {
2616 int ret;
2617
2618 entry = rb_entry(node, struct btrfs_free_space, offset_index);
2619 node = rb_next(&entry->offset_index);
2620 if (entry->bitmap || entry->bytes < min_bytes)
2621 continue;
2622
2623 rb_erase(&entry->offset_index, &ctl->free_space_offset);
2624 ret = tree_insert_offset(&cluster->root, entry->offset,
2625 &entry->offset_index, 0);
2626 total_size += entry->bytes;
2627 ASSERT(!ret); /* -EEXIST; Logic error */
2628 } while (node && entry != last);
2629
2630 cluster->max_size = max_extent;
2631 trace_btrfs_setup_cluster(block_group, cluster, total_size, 0);
2632 return 0;
2633 }
2634
2635 /*
2636 * This specifically looks for bitmaps that may work in the cluster, we assume
2637 * that we have already failed to find extents that will work.
2638 */
2639 static noinline int
2640 setup_cluster_bitmap(struct btrfs_block_group_cache *block_group,
2641 struct btrfs_free_cluster *cluster,
2642 struct list_head *bitmaps, u64 offset, u64 bytes,
2643 u64 cont1_bytes, u64 min_bytes)
2644 {
2645 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2646 struct btrfs_free_space *entry;
2647 int ret = -ENOSPC;
2648 u64 bitmap_offset = offset_to_bitmap(ctl, offset);
2649
2650 if (ctl->total_bitmaps == 0)
2651 return -ENOSPC;
2652
2653 /*
2654 * The bitmap that covers offset won't be in the list unless offset
2655 * is just its start offset.
2656 */
2657 entry = list_first_entry(bitmaps, struct btrfs_free_space, list);
2658 if (entry->offset != bitmap_offset) {
2659 entry = tree_search_offset(ctl, bitmap_offset, 1, 0);
2660 if (entry && list_empty(&entry->list))
2661 list_add(&entry->list, bitmaps);
2662 }
2663
2664 list_for_each_entry(entry, bitmaps, list) {
2665 if (entry->bytes < bytes)
2666 continue;
2667 ret = btrfs_bitmap_cluster(block_group, entry, cluster, offset,
2668 bytes, cont1_bytes, min_bytes);
2669 if (!ret)
2670 return 0;
2671 }
2672
2673 /*
2674 * The bitmaps list has all the bitmaps that record free space
2675 * starting after offset, so no more search is required.
2676 */
2677 return -ENOSPC;
2678 }
2679
2680 /*
2681 * here we try to find a cluster of blocks in a block group. The goal
2682 * is to find at least bytes+empty_size.
2683 * We might not find them all in one contiguous area.
2684 *
2685 * returns zero and sets up cluster if things worked out, otherwise
2686 * it returns -enospc
2687 */
2688 int btrfs_find_space_cluster(struct btrfs_root *root,
2689 struct btrfs_block_group_cache *block_group,
2690 struct btrfs_free_cluster *cluster,
2691 u64 offset, u64 bytes, u64 empty_size)
2692 {
2693 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2694 struct btrfs_free_space *entry, *tmp;
2695 LIST_HEAD(bitmaps);
2696 u64 min_bytes;
2697 u64 cont1_bytes;
2698 int ret;
2699
2700 /*
2701 * Choose the minimum extent size we'll require for this
2702 * cluster. For SSD_SPREAD, don't allow any fragmentation.
2703 * For metadata, allow allocates with smaller extents. For
2704 * data, keep it dense.
2705 */
2706 if (btrfs_test_opt(root, SSD_SPREAD)) {
2707 cont1_bytes = min_bytes = bytes + empty_size;
2708 } else if (block_group->flags & BTRFS_BLOCK_GROUP_METADATA) {
2709 cont1_bytes = bytes;
2710 min_bytes = block_group->sectorsize;
2711 } else {
2712 cont1_bytes = max(bytes, (bytes + empty_size) >> 2);
2713 min_bytes = block_group->sectorsize;
2714 }
2715
2716 spin_lock(&ctl->tree_lock);
2717
2718 /*
2719 * If we know we don't have enough space to make a cluster don't even
2720 * bother doing all the work to try and find one.
2721 */
2722 if (ctl->free_space < bytes) {
2723 spin_unlock(&ctl->tree_lock);
2724 return -ENOSPC;
2725 }
2726
2727 spin_lock(&cluster->lock);
2728
2729 /* someone already found a cluster, hooray */
2730 if (cluster->block_group) {
2731 ret = 0;
2732 goto out;
2733 }
2734
2735 trace_btrfs_find_cluster(block_group, offset, bytes, empty_size,
2736 min_bytes);
2737
2738 INIT_LIST_HEAD(&bitmaps);
2739 ret = setup_cluster_no_bitmap(block_group, cluster, &bitmaps, offset,
2740 bytes + empty_size,
2741 cont1_bytes, min_bytes);
2742 if (ret)
2743 ret = setup_cluster_bitmap(block_group, cluster, &bitmaps,
2744 offset, bytes + empty_size,
2745 cont1_bytes, min_bytes);
2746
2747 /* Clear our temporary list */
2748 list_for_each_entry_safe(entry, tmp, &bitmaps, list)
2749 list_del_init(&entry->list);
2750
2751 if (!ret) {
2752 atomic_inc(&block_group->count);
2753 list_add_tail(&cluster->block_group_list,
2754 &block_group->cluster_list);
2755 cluster->block_group = block_group;
2756 } else {
2757 trace_btrfs_failed_cluster_setup(block_group);
2758 }
2759 out:
2760 spin_unlock(&cluster->lock);
2761 spin_unlock(&ctl->tree_lock);
2762
2763 return ret;
2764 }
2765
2766 /*
2767 * simple code to zero out a cluster
2768 */
2769 void btrfs_init_free_cluster(struct btrfs_free_cluster *cluster)
2770 {
2771 spin_lock_init(&cluster->lock);
2772 spin_lock_init(&cluster->refill_lock);
2773 cluster->root = RB_ROOT;
2774 cluster->max_size = 0;
2775 INIT_LIST_HEAD(&cluster->block_group_list);
2776 cluster->block_group = NULL;
2777 }
2778
2779 static int do_trimming(struct btrfs_block_group_cache *block_group,
2780 u64 *total_trimmed, u64 start, u64 bytes,
2781 u64 reserved_start, u64 reserved_bytes)
2782 {
2783 struct btrfs_space_info *space_info = block_group->space_info;
2784 struct btrfs_fs_info *fs_info = block_group->fs_info;
2785 int ret;
2786 int update = 0;
2787 u64 trimmed = 0;
2788
2789 spin_lock(&space_info->lock);
2790 spin_lock(&block_group->lock);
2791 if (!block_group->ro) {
2792 block_group->reserved += reserved_bytes;
2793 space_info->bytes_reserved += reserved_bytes;
2794 update = 1;
2795 }
2796 spin_unlock(&block_group->lock);
2797 spin_unlock(&space_info->lock);
2798
2799 ret = btrfs_error_discard_extent(fs_info->extent_root,
2800 start, bytes, &trimmed);
2801 if (!ret)
2802 *total_trimmed += trimmed;
2803
2804 btrfs_add_free_space(block_group, reserved_start, reserved_bytes);
2805
2806 if (update) {
2807 spin_lock(&space_info->lock);
2808 spin_lock(&block_group->lock);
2809 if (block_group->ro)
2810 space_info->bytes_readonly += reserved_bytes;
2811 block_group->reserved -= reserved_bytes;
2812 space_info->bytes_reserved -= reserved_bytes;
2813 spin_unlock(&space_info->lock);
2814 spin_unlock(&block_group->lock);
2815 }
2816
2817 return ret;
2818 }
2819
2820 static int trim_no_bitmap(struct btrfs_block_group_cache *block_group,
2821 u64 *total_trimmed, u64 start, u64 end, u64 minlen)
2822 {
2823 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2824 struct btrfs_free_space *entry;
2825 struct rb_node *node;
2826 int ret = 0;
2827 u64 extent_start;
2828 u64 extent_bytes;
2829 u64 bytes;
2830
2831 while (start < end) {
2832 spin_lock(&ctl->tree_lock);
2833
2834 if (ctl->free_space < minlen) {
2835 spin_unlock(&ctl->tree_lock);
2836 break;
2837 }
2838
2839 entry = tree_search_offset(ctl, start, 0, 1);
2840 if (!entry) {
2841 spin_unlock(&ctl->tree_lock);
2842 break;
2843 }
2844
2845 /* skip bitmaps */
2846 while (entry->bitmap) {
2847 node = rb_next(&entry->offset_index);
2848 if (!node) {
2849 spin_unlock(&ctl->tree_lock);
2850 goto out;
2851 }
2852 entry = rb_entry(node, struct btrfs_free_space,
2853 offset_index);
2854 }
2855
2856 if (entry->offset >= end) {
2857 spin_unlock(&ctl->tree_lock);
2858 break;
2859 }
2860
2861 extent_start = entry->offset;
2862 extent_bytes = entry->bytes;
2863 start = max(start, extent_start);
2864 bytes = min(extent_start + extent_bytes, end) - start;
2865 if (bytes < minlen) {
2866 spin_unlock(&ctl->tree_lock);
2867 goto next;
2868 }
2869
2870 unlink_free_space(ctl, entry);
2871 kmem_cache_free(btrfs_free_space_cachep, entry);
2872
2873 spin_unlock(&ctl->tree_lock);
2874
2875 ret = do_trimming(block_group, total_trimmed, start, bytes,
2876 extent_start, extent_bytes);
2877 if (ret)
2878 break;
2879 next:
2880 start += bytes;
2881
2882 if (fatal_signal_pending(current)) {
2883 ret = -ERESTARTSYS;
2884 break;
2885 }
2886
2887 cond_resched();
2888 }
2889 out:
2890 return ret;
2891 }
2892
2893 static int trim_bitmaps(struct btrfs_block_group_cache *block_group,
2894 u64 *total_trimmed, u64 start, u64 end, u64 minlen)
2895 {
2896 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2897 struct btrfs_free_space *entry;
2898 int ret = 0;
2899 int ret2;
2900 u64 bytes;
2901 u64 offset = offset_to_bitmap(ctl, start);
2902
2903 while (offset < end) {
2904 bool next_bitmap = false;
2905
2906 spin_lock(&ctl->tree_lock);
2907
2908 if (ctl->free_space < minlen) {
2909 spin_unlock(&ctl->tree_lock);
2910 break;
2911 }
2912
2913 entry = tree_search_offset(ctl, offset, 1, 0);
2914 if (!entry) {
2915 spin_unlock(&ctl->tree_lock);
2916 next_bitmap = true;
2917 goto next;
2918 }
2919
2920 bytes = minlen;
2921 ret2 = search_bitmap(ctl, entry, &start, &bytes);
2922 if (ret2 || start >= end) {
2923 spin_unlock(&ctl->tree_lock);
2924 next_bitmap = true;
2925 goto next;
2926 }
2927
2928 bytes = min(bytes, end - start);
2929 if (bytes < minlen) {
2930 spin_unlock(&ctl->tree_lock);
2931 goto next;
2932 }
2933
2934 bitmap_clear_bits(ctl, entry, start, bytes);
2935 if (entry->bytes == 0)
2936 free_bitmap(ctl, entry);
2937
2938 spin_unlock(&ctl->tree_lock);
2939
2940 ret = do_trimming(block_group, total_trimmed, start, bytes,
2941 start, bytes);
2942 if (ret)
2943 break;
2944 next:
2945 if (next_bitmap) {
2946 offset += BITS_PER_BITMAP * ctl->unit;
2947 } else {
2948 start += bytes;
2949 if (start >= offset + BITS_PER_BITMAP * ctl->unit)
2950 offset += BITS_PER_BITMAP * ctl->unit;
2951 }
2952
2953 if (fatal_signal_pending(current)) {
2954 ret = -ERESTARTSYS;
2955 break;
2956 }
2957
2958 cond_resched();
2959 }
2960
2961 return ret;
2962 }
2963
2964 int btrfs_trim_block_group(struct btrfs_block_group_cache *block_group,
2965 u64 *trimmed, u64 start, u64 end, u64 minlen)
2966 {
2967 int ret;
2968
2969 *trimmed = 0;
2970
2971 ret = trim_no_bitmap(block_group, trimmed, start, end, minlen);
2972 if (ret)
2973 return ret;
2974
2975 ret = trim_bitmaps(block_group, trimmed, start, end, minlen);
2976
2977 return ret;
2978 }
2979
2980 /*
2981 * Find the left-most item in the cache tree, and then return the
2982 * smallest inode number in the item.
2983 *
2984 * Note: the returned inode number may not be the smallest one in
2985 * the tree, if the left-most item is a bitmap.
2986 */
2987 u64 btrfs_find_ino_for_alloc(struct btrfs_root *fs_root)
2988 {
2989 struct btrfs_free_space_ctl *ctl = fs_root->free_ino_ctl;
2990 struct btrfs_free_space *entry = NULL;
2991 u64 ino = 0;
2992
2993 spin_lock(&ctl->tree_lock);
2994
2995 if (RB_EMPTY_ROOT(&ctl->free_space_offset))
2996 goto out;
2997
2998 entry = rb_entry(rb_first(&ctl->free_space_offset),
2999 struct btrfs_free_space, offset_index);
3000
3001 if (!entry->bitmap) {
3002 ino = entry->offset;
3003
3004 unlink_free_space(ctl, entry);
3005 entry->offset++;
3006 entry->bytes--;
3007 if (!entry->bytes)
3008 kmem_cache_free(btrfs_free_space_cachep, entry);
3009 else
3010 link_free_space(ctl, entry);
3011 } else {
3012 u64 offset = 0;
3013 u64 count = 1;
3014 int ret;
3015
3016 ret = search_bitmap(ctl, entry, &offset, &count);
3017 /* Logic error; Should be empty if it can't find anything */
3018 ASSERT(!ret);
3019
3020 ino = offset;
3021 bitmap_clear_bits(ctl, entry, offset, 1);
3022 if (entry->bytes == 0)
3023 free_bitmap(ctl, entry);
3024 }
3025 out:
3026 spin_unlock(&ctl->tree_lock);
3027
3028 return ino;
3029 }
3030
3031 struct inode *lookup_free_ino_inode(struct btrfs_root *root,
3032 struct btrfs_path *path)
3033 {
3034 struct inode *inode = NULL;
3035
3036 spin_lock(&root->cache_lock);
3037 if (root->cache_inode)
3038 inode = igrab(root->cache_inode);
3039 spin_unlock(&root->cache_lock);
3040 if (inode)
3041 return inode;
3042
3043 inode = __lookup_free_space_inode(root, path, 0);
3044 if (IS_ERR(inode))
3045 return inode;
3046
3047 spin_lock(&root->cache_lock);
3048 if (!btrfs_fs_closing(root->fs_info))
3049 root->cache_inode = igrab(inode);
3050 spin_unlock(&root->cache_lock);
3051
3052 return inode;
3053 }
3054
3055 int create_free_ino_inode(struct btrfs_root *root,
3056 struct btrfs_trans_handle *trans,
3057 struct btrfs_path *path)
3058 {
3059 return __create_free_space_inode(root, trans, path,
3060 BTRFS_FREE_INO_OBJECTID, 0);
3061 }
3062
3063 int load_free_ino_cache(struct btrfs_fs_info *fs_info, struct btrfs_root *root)
3064 {
3065 struct btrfs_free_space_ctl *ctl = root->free_ino_ctl;
3066 struct btrfs_path *path;
3067 struct inode *inode;
3068 int ret = 0;
3069 u64 root_gen = btrfs_root_generation(&root->root_item);
3070
3071 if (!btrfs_test_opt(root, INODE_MAP_CACHE))
3072 return 0;
3073
3074 /*
3075 * If we're unmounting then just return, since this does a search on the
3076 * normal root and not the commit root and we could deadlock.
3077 */
3078 if (btrfs_fs_closing(fs_info))
3079 return 0;
3080
3081 path = btrfs_alloc_path();
3082 if (!path)
3083 return 0;
3084
3085 inode = lookup_free_ino_inode(root, path);
3086 if (IS_ERR(inode))
3087 goto out;
3088
3089 if (root_gen != BTRFS_I(inode)->generation)
3090 goto out_put;
3091
3092 ret = __load_free_space_cache(root, inode, ctl, path, 0);
3093
3094 if (ret < 0)
3095 btrfs_err(fs_info,
3096 "failed to load free ino cache for root %llu",
3097 root->root_key.objectid);
3098 out_put:
3099 iput(inode);
3100 out:
3101 btrfs_free_path(path);
3102 return ret;
3103 }
3104
3105 int btrfs_write_out_ino_cache(struct btrfs_root *root,
3106 struct btrfs_trans_handle *trans,
3107 struct btrfs_path *path,
3108 struct inode *inode)
3109 {
3110 struct btrfs_free_space_ctl *ctl = root->free_ino_ctl;
3111 int ret;
3112
3113 if (!btrfs_test_opt(root, INODE_MAP_CACHE))
3114 return 0;
3115
3116 ret = __btrfs_write_out_cache(root, inode, ctl, NULL, trans, path, 0);
3117 if (ret) {
3118 btrfs_delalloc_release_metadata(inode, inode->i_size);
3119 #ifdef DEBUG
3120 btrfs_err(root->fs_info,
3121 "failed to write free ino cache for root %llu",
3122 root->root_key.objectid);
3123 #endif
3124 }
3125
3126 return ret;
3127 }
3128
3129 #ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
3130 /*
3131 * Use this if you need to make a bitmap or extent entry specifically, it
3132 * doesn't do any of the merging that add_free_space does, this acts a lot like
3133 * how the free space cache loading stuff works, so you can get really weird
3134 * configurations.
3135 */
3136 int test_add_free_space_entry(struct btrfs_block_group_cache *cache,
3137 u64 offset, u64 bytes, bool bitmap)
3138 {
3139 struct btrfs_free_space_ctl *ctl = cache->free_space_ctl;
3140 struct btrfs_free_space *info = NULL, *bitmap_info;
3141 void *map = NULL;
3142 u64 bytes_added;
3143 int ret;
3144
3145 again:
3146 if (!info) {
3147 info = kmem_cache_zalloc(btrfs_free_space_cachep, GFP_NOFS);
3148 if (!info)
3149 return -ENOMEM;
3150 }
3151
3152 if (!bitmap) {
3153 spin_lock(&ctl->tree_lock);
3154 info->offset = offset;
3155 info->bytes = bytes;
3156 ret = link_free_space(ctl, info);
3157 spin_unlock(&ctl->tree_lock);
3158 if (ret)
3159 kmem_cache_free(btrfs_free_space_cachep, info);
3160 return ret;
3161 }
3162
3163 if (!map) {
3164 map = kzalloc(PAGE_CACHE_SIZE, GFP_NOFS);
3165 if (!map) {
3166 kmem_cache_free(btrfs_free_space_cachep, info);
3167 return -ENOMEM;
3168 }
3169 }
3170
3171 spin_lock(&ctl->tree_lock);
3172 bitmap_info = tree_search_offset(ctl, offset_to_bitmap(ctl, offset),
3173 1, 0);
3174 if (!bitmap_info) {
3175 info->bitmap = map;
3176 map = NULL;
3177 add_new_bitmap(ctl, info, offset);
3178 bitmap_info = info;
3179 }
3180
3181 bytes_added = add_bytes_to_bitmap(ctl, bitmap_info, offset, bytes);
3182 bytes -= bytes_added;
3183 offset += bytes_added;
3184 spin_unlock(&ctl->tree_lock);
3185
3186 if (bytes)
3187 goto again;
3188
3189 if (map)
3190 kfree(map);
3191 return 0;
3192 }
3193
3194 /*
3195 * Checks to see if the given range is in the free space cache. This is really
3196 * just used to check the absence of space, so if there is free space in the
3197 * range at all we will return 1.
3198 */
3199 int test_check_exists(struct btrfs_block_group_cache *cache,
3200 u64 offset, u64 bytes)
3201 {
3202 struct btrfs_free_space_ctl *ctl = cache->free_space_ctl;
3203 struct btrfs_free_space *info;
3204 int ret = 0;
3205
3206 spin_lock(&ctl->tree_lock);
3207 info = tree_search_offset(ctl, offset, 0, 0);
3208 if (!info) {
3209 info = tree_search_offset(ctl, offset_to_bitmap(ctl, offset),
3210 1, 0);
3211 if (!info)
3212 goto out;
3213 }
3214
3215 have_info:
3216 if (info->bitmap) {
3217 u64 bit_off, bit_bytes;
3218 struct rb_node *n;
3219 struct btrfs_free_space *tmp;
3220
3221 bit_off = offset;
3222 bit_bytes = ctl->unit;
3223 ret = search_bitmap(ctl, info, &bit_off, &bit_bytes);
3224 if (!ret) {
3225 if (bit_off == offset) {
3226 ret = 1;
3227 goto out;
3228 } else if (bit_off > offset &&
3229 offset + bytes > bit_off) {
3230 ret = 1;
3231 goto out;
3232 }
3233 }
3234
3235 n = rb_prev(&info->offset_index);
3236 while (n) {
3237 tmp = rb_entry(n, struct btrfs_free_space,
3238 offset_index);
3239 if (tmp->offset + tmp->bytes < offset)
3240 break;
3241 if (offset + bytes < tmp->offset) {
3242 n = rb_prev(&info->offset_index);
3243 continue;
3244 }
3245 info = tmp;
3246 goto have_info;
3247 }
3248
3249 n = rb_next(&info->offset_index);
3250 while (n) {
3251 tmp = rb_entry(n, struct btrfs_free_space,
3252 offset_index);
3253 if (offset + bytes < tmp->offset)
3254 break;
3255 if (tmp->offset + tmp->bytes < offset) {
3256 n = rb_next(&info->offset_index);
3257 continue;
3258 }
3259 info = tmp;
3260 goto have_info;
3261 }
3262
3263 goto out;
3264 }
3265
3266 if (info->offset == offset) {
3267 ret = 1;
3268 goto out;
3269 }
3270
3271 if (offset > info->offset && offset < info->offset + info->bytes)
3272 ret = 1;
3273 out:
3274 spin_unlock(&ctl->tree_lock);
3275 return ret;
3276 }
3277 #endif /* CONFIG_BTRFS_FS_RUN_SANITY_TESTS */
Linux kernel - Deliverables
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