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[linux-2.6.git] / fs / btrfs / free-space-cache.c
blob6c4e2baa9290e16d06a4a8dfc5c3b05880cfeb27
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 printk(KERN_INFO "Old style space inode found, converting.\n");
108 BTRFS_I(inode)->flags |= BTRFS_INODE_NODATASUM |
109 BTRFS_INODE_NODATACOW;
110 block_group->disk_cache_state = BTRFS_DC_CLEAR;
111 }
112
113 if (!block_group->iref) {
114 block_group->inode = igrab(inode);
115 block_group->iref = 1;
116 }
117 spin_unlock(&block_group->lock);
118
119 return inode;
120 }
121
122 int __create_free_space_inode(struct btrfs_root *root,
123 struct btrfs_trans_handle *trans,
124 struct btrfs_path *path, u64 ino, u64 offset)
125 {
126 struct btrfs_key key;
127 struct btrfs_disk_key disk_key;
128 struct btrfs_free_space_header *header;
129 struct btrfs_inode_item *inode_item;
130 struct extent_buffer *leaf;
131 u64 flags = BTRFS_INODE_NOCOMPRESS | BTRFS_INODE_PREALLOC;
132 int ret;
133
134 ret = btrfs_insert_empty_inode(trans, root, path, ino);
135 if (ret)
136 return ret;
137
138 /* We inline crc's for the free disk space cache */
139 if (ino != BTRFS_FREE_INO_OBJECTID)
140 flags |= BTRFS_INODE_NODATASUM | BTRFS_INODE_NODATACOW;
141
142 leaf = path->nodes[0];
143 inode_item = btrfs_item_ptr(leaf, path->slots[0],
144 struct btrfs_inode_item);
145 btrfs_item_key(leaf, &disk_key, path->slots[0]);
146 memset_extent_buffer(leaf, 0, (unsigned long)inode_item,
147 sizeof(*inode_item));
148 btrfs_set_inode_generation(leaf, inode_item, trans->transid);
149 btrfs_set_inode_size(leaf, inode_item, 0);
150 btrfs_set_inode_nbytes(leaf, inode_item, 0);
151 btrfs_set_inode_uid(leaf, inode_item, 0);
152 btrfs_set_inode_gid(leaf, inode_item, 0);
153 btrfs_set_inode_mode(leaf, inode_item, S_IFREG | 0600);
154 btrfs_set_inode_flags(leaf, inode_item, flags);
155 btrfs_set_inode_nlink(leaf, inode_item, 1);
156 btrfs_set_inode_transid(leaf, inode_item, trans->transid);
157 btrfs_set_inode_block_group(leaf, inode_item, offset);
158 btrfs_mark_buffer_dirty(leaf);
159 btrfs_release_path(path);
160
161 key.objectid = BTRFS_FREE_SPACE_OBJECTID;
162 key.offset = offset;
163 key.type = 0;
164
165 ret = btrfs_insert_empty_item(trans, root, path, &key,
166 sizeof(struct btrfs_free_space_header));
167 if (ret < 0) {
168 btrfs_release_path(path);
169 return ret;
170 }
171 leaf = path->nodes[0];
172 header = btrfs_item_ptr(leaf, path->slots[0],
173 struct btrfs_free_space_header);
174 memset_extent_buffer(leaf, 0, (unsigned long)header, sizeof(*header));
175 btrfs_set_free_space_key(leaf, header, &disk_key);
176 btrfs_mark_buffer_dirty(leaf);
177 btrfs_release_path(path);
178
179 return 0;
180 }
181
182 int create_free_space_inode(struct btrfs_root *root,
183 struct btrfs_trans_handle *trans,
184 struct btrfs_block_group_cache *block_group,
185 struct btrfs_path *path)
186 {
187 int ret;
188 u64 ino;
189
190 ret = btrfs_find_free_objectid(root, &ino);
191 if (ret < 0)
192 return ret;
193
194 return __create_free_space_inode(root, trans, path, ino,
195 block_group->key.objectid);
196 }
197
198 int btrfs_truncate_free_space_cache(struct btrfs_root *root,
199 struct btrfs_trans_handle *trans,
200 struct btrfs_path *path,
201 struct inode *inode)
202 {
203 struct btrfs_block_rsv *rsv;
204 u64 needed_bytes;
205 loff_t oldsize;
206 int ret = 0;
207
208 rsv = trans->block_rsv;
209 trans->block_rsv = &root->fs_info->global_block_rsv;
210
211 /* 1 for slack space, 1 for updating the inode */
212 needed_bytes = btrfs_calc_trunc_metadata_size(root, 1) +
213 btrfs_calc_trans_metadata_size(root, 1);
214
215 spin_lock(&trans->block_rsv->lock);
216 if (trans->block_rsv->reserved < needed_bytes) {
217 spin_unlock(&trans->block_rsv->lock);
218 trans->block_rsv = rsv;
219 return -ENOSPC;
220 }
221 spin_unlock(&trans->block_rsv->lock);
222
223 oldsize = i_size_read(inode);
224 btrfs_i_size_write(inode, 0);
225 truncate_pagecache(inode, oldsize, 0);
226
227 /*
228 * We don't need an orphan item because truncating the free space cache
229 * will never be split across transactions.
230 */
231 ret = btrfs_truncate_inode_items(trans, root, inode,
232 0, BTRFS_EXTENT_DATA_KEY);
233
234 if (ret) {
235 trans->block_rsv = rsv;
236 btrfs_abort_transaction(trans, root, ret);
237 return ret;
238 }
239
240 ret = btrfs_update_inode(trans, root, inode);
241 if (ret)
242 btrfs_abort_transaction(trans, root, ret);
243 trans->block_rsv = rsv;
244
245 return ret;
246 }
247
248 static int readahead_cache(struct inode *inode)
249 {
250 struct file_ra_state *ra;
251 unsigned long last_index;
252
253 ra = kzalloc(sizeof(*ra), GFP_NOFS);
254 if (!ra)
255 return -ENOMEM;
256
257 file_ra_state_init(ra, inode->i_mapping);
258 last_index = (i_size_read(inode) - 1) >> PAGE_CACHE_SHIFT;
259
260 page_cache_sync_readahead(inode->i_mapping, ra, NULL, 0, last_index);
261
262 kfree(ra);
263
264 return 0;
265 }
266
267 struct io_ctl {
268 void *cur, *orig;
269 struct page *page;
270 struct page **pages;
271 struct btrfs_root *root;
272 unsigned long size;
273 int index;
274 int num_pages;
275 unsigned check_crcs:1;
276 };
277
278 static int io_ctl_init(struct io_ctl *io_ctl, struct inode *inode,
279 struct btrfs_root *root)
280 {
281 memset(io_ctl, 0, sizeof(struct io_ctl));
282 io_ctl->num_pages = (i_size_read(inode) + PAGE_CACHE_SIZE - 1) >>
283 PAGE_CACHE_SHIFT;
284 io_ctl->pages = kzalloc(sizeof(struct page *) * io_ctl->num_pages,
285 GFP_NOFS);
286 if (!io_ctl->pages)
287 return -ENOMEM;
288 io_ctl->root = root;
289 if (btrfs_ino(inode) != BTRFS_FREE_INO_OBJECTID)
290 io_ctl->check_crcs = 1;
291 return 0;
292 }
293
294 static void io_ctl_free(struct io_ctl *io_ctl)
295 {
296 kfree(io_ctl->pages);
297 }
298
299 static void io_ctl_unmap_page(struct io_ctl *io_ctl)
300 {
301 if (io_ctl->cur) {
302 kunmap(io_ctl->page);
303 io_ctl->cur = NULL;
304 io_ctl->orig = NULL;
305 }
306 }
307
308 static void io_ctl_map_page(struct io_ctl *io_ctl, int clear)
309 {
310 WARN_ON(io_ctl->cur);
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->root, 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->root, 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 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 printk(KERN_ERR "btrfs: free space inode generation (%llu) did"
674 " not match free space cache generation (%llu)\n",
675 (unsigned long long)BTRFS_I(inode)->generation,
676 (unsigned long long)generation);
677 return 0;
678 }
679
680 if (!num_entries)
681 return 0;
682
683 ret = io_ctl_init(&io_ctl, inode, root);
684 if (ret)
685 return ret;
686
687 ret = readahead_cache(inode);
688 if (ret)
689 goto out;
690
691 ret = io_ctl_prepare_pages(&io_ctl, inode, 1);
692 if (ret)
693 goto out;
694
695 ret = io_ctl_check_crc(&io_ctl, 0);
696 if (ret)
697 goto free_cache;
698
699 ret = io_ctl_check_generation(&io_ctl, generation);
700 if (ret)
701 goto free_cache;
702
703 while (num_entries) {
704 e = kmem_cache_zalloc(btrfs_free_space_cachep,
705 GFP_NOFS);
706 if (!e)
707 goto free_cache;
708
709 ret = io_ctl_read_entry(&io_ctl, e, &type);
710 if (ret) {
711 kmem_cache_free(btrfs_free_space_cachep, e);
712 goto free_cache;
713 }
714
715 if (!e->bytes) {
716 kmem_cache_free(btrfs_free_space_cachep, e);
717 goto free_cache;
718 }
719
720 if (type == BTRFS_FREE_SPACE_EXTENT) {
721 spin_lock(&ctl->tree_lock);
722 ret = link_free_space(ctl, e);
723 spin_unlock(&ctl->tree_lock);
724 if (ret) {
725 printk(KERN_ERR "Duplicate entries in "
726 "free space cache, dumping\n");
727 kmem_cache_free(btrfs_free_space_cachep, e);
728 goto free_cache;
729 }
730 } else {
731 BUG_ON(!num_bitmaps);
732 num_bitmaps--;
733 e->bitmap = kzalloc(PAGE_CACHE_SIZE, GFP_NOFS);
734 if (!e->bitmap) {
735 kmem_cache_free(
736 btrfs_free_space_cachep, e);
737 goto free_cache;
738 }
739 spin_lock(&ctl->tree_lock);
740 ret = link_free_space(ctl, e);
741 ctl->total_bitmaps++;
742 ctl->op->recalc_thresholds(ctl);
743 spin_unlock(&ctl->tree_lock);
744 if (ret) {
745 printk(KERN_ERR "Duplicate entries in "
746 "free space cache, dumping\n");
747 kmem_cache_free(btrfs_free_space_cachep, e);
748 goto free_cache;
749 }
750 list_add_tail(&e->list, &bitmaps);
751 }
752
753 num_entries--;
754 }
755
756 io_ctl_unmap_page(&io_ctl);
757
758 /*
759 * We add the bitmaps at the end of the entries in order that
760 * the bitmap entries are added to the cache.
761 */
762 list_for_each_entry_safe(e, n, &bitmaps, list) {
763 list_del_init(&e->list);
764 ret = io_ctl_read_bitmap(&io_ctl, e);
765 if (ret)
766 goto free_cache;
767 }
768
769 io_ctl_drop_pages(&io_ctl);
770 merge_space_tree(ctl);
771 ret = 1;
772 out:
773 io_ctl_free(&io_ctl);
774 return ret;
775 free_cache:
776 io_ctl_drop_pages(&io_ctl);
777 __btrfs_remove_free_space_cache(ctl);
778 goto out;
779 }
780
781 int load_free_space_cache(struct btrfs_fs_info *fs_info,
782 struct btrfs_block_group_cache *block_group)
783 {
784 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
785 struct btrfs_root *root = fs_info->tree_root;
786 struct inode *inode;
787 struct btrfs_path *path;
788 int ret = 0;
789 bool matched;
790 u64 used = btrfs_block_group_used(&block_group->item);
791
792 /*
793 * If this block group has been marked to be cleared for one reason or
794 * another then we can't trust the on disk cache, so just return.
795 */
796 spin_lock(&block_group->lock);
797 if (block_group->disk_cache_state != BTRFS_DC_WRITTEN) {
798 spin_unlock(&block_group->lock);
799 return 0;
800 }
801 spin_unlock(&block_group->lock);
802
803 path = btrfs_alloc_path();
804 if (!path)
805 return 0;
806 path->search_commit_root = 1;
807 path->skip_locking = 1;
808
809 inode = lookup_free_space_inode(root, block_group, path);
810 if (IS_ERR(inode)) {
811 btrfs_free_path(path);
812 return 0;
813 }
814
815 /* We may have converted the inode and made the cache invalid. */
816 spin_lock(&block_group->lock);
817 if (block_group->disk_cache_state != BTRFS_DC_WRITTEN) {
818 spin_unlock(&block_group->lock);
819 btrfs_free_path(path);
820 goto out;
821 }
822 spin_unlock(&block_group->lock);
823
824 ret = __load_free_space_cache(fs_info->tree_root, inode, ctl,
825 path, block_group->key.objectid);
826 btrfs_free_path(path);
827 if (ret <= 0)
828 goto out;
829
830 spin_lock(&ctl->tree_lock);
831 matched = (ctl->free_space == (block_group->key.offset - used -
832 block_group->bytes_super));
833 spin_unlock(&ctl->tree_lock);
834
835 if (!matched) {
836 __btrfs_remove_free_space_cache(ctl);
837 printk(KERN_ERR "block group %llu has an wrong amount of free "
838 "space\n", block_group->key.objectid);
839 ret = -1;
840 }
841 out:
842 if (ret < 0) {
843 /* This cache is bogus, make sure it gets cleared */
844 spin_lock(&block_group->lock);
845 block_group->disk_cache_state = BTRFS_DC_CLEAR;
846 spin_unlock(&block_group->lock);
847 ret = 0;
848
849 printk(KERN_ERR "btrfs: failed to load free space cache "
850 "for block group %llu\n", block_group->key.objectid);
851 }
852
853 iput(inode);
854 return ret;
855 }
856
857 /**
858 * __btrfs_write_out_cache - write out cached info to an inode
859 * @root - the root the inode belongs to
860 * @ctl - the free space cache we are going to write out
861 * @block_group - the block_group for this cache if it belongs to a block_group
862 * @trans - the trans handle
863 * @path - the path to use
864 * @offset - the offset for the key we'll insert
865 *
866 * This function writes out a free space cache struct to disk for quick recovery
867 * on mount. This will return 0 if it was successfull in writing the cache out,
868 * and -1 if it was not.
869 */
870 int __btrfs_write_out_cache(struct btrfs_root *root, struct inode *inode,
871 struct btrfs_free_space_ctl *ctl,
872 struct btrfs_block_group_cache *block_group,
873 struct btrfs_trans_handle *trans,
874 struct btrfs_path *path, u64 offset)
875 {
876 struct btrfs_free_space_header *header;
877 struct extent_buffer *leaf;
878 struct rb_node *node;
879 struct list_head *pos, *n;
880 struct extent_state *cached_state = NULL;
881 struct btrfs_free_cluster *cluster = NULL;
882 struct extent_io_tree *unpin = NULL;
883 struct io_ctl io_ctl;
884 struct list_head bitmap_list;
885 struct btrfs_key key;
886 u64 start, extent_start, extent_end, len;
887 int entries = 0;
888 int bitmaps = 0;
889 int ret;
890 int err = -1;
891
892 INIT_LIST_HEAD(&bitmap_list);
893
894 if (!i_size_read(inode))
895 return -1;
896
897 ret = io_ctl_init(&io_ctl, inode, root);
898 if (ret)
899 return -1;
900
901 /* Get the cluster for this block_group if it exists */
902 if (block_group && !list_empty(&block_group->cluster_list))
903 cluster = list_entry(block_group->cluster_list.next,
904 struct btrfs_free_cluster,
905 block_group_list);
906
907 /* Lock all pages first so we can lock the extent safely. */
908 io_ctl_prepare_pages(&io_ctl, inode, 0);
909
910 lock_extent_bits(&BTRFS_I(inode)->io_tree, 0, i_size_read(inode) - 1,
911 0, &cached_state);
912
913 node = rb_first(&ctl->free_space_offset);
914 if (!node && cluster) {
915 node = rb_first(&cluster->root);
916 cluster = NULL;
917 }
918
919 /* Make sure we can fit our crcs into the first page */
920 if (io_ctl.check_crcs &&
921 (io_ctl.num_pages * sizeof(u32)) >= PAGE_CACHE_SIZE) {
922 WARN_ON(1);
923 goto out_nospc;
924 }
925
926 io_ctl_set_generation(&io_ctl, trans->transid);
927
928 /* Write out the extent entries */
929 while (node) {
930 struct btrfs_free_space *e;
931
932 e = rb_entry(node, struct btrfs_free_space, offset_index);
933 entries++;
934
935 ret = io_ctl_add_entry(&io_ctl, e->offset, e->bytes,
936 e->bitmap);
937 if (ret)
938 goto out_nospc;
939
940 if (e->bitmap) {
941 list_add_tail(&e->list, &bitmap_list);
942 bitmaps++;
943 }
944 node = rb_next(node);
945 if (!node && cluster) {
946 node = rb_first(&cluster->root);
947 cluster = NULL;
948 }
949 }
950
951 /*
952 * We want to add any pinned extents to our free space cache
953 * so we don't leak the space
954 */
955
956 /*
957 * We shouldn't have switched the pinned extents yet so this is the
958 * right one
959 */
960 unpin = root->fs_info->pinned_extents;
961
962 if (block_group)
963 start = block_group->key.objectid;
964
965 while (block_group && (start < block_group->key.objectid +
966 block_group->key.offset)) {
967 ret = find_first_extent_bit(unpin, start,
968 &extent_start, &extent_end,
969 EXTENT_DIRTY);
970 if (ret) {
971 ret = 0;
972 break;
973 }
974
975 /* This pinned extent is out of our range */
976 if (extent_start >= block_group->key.objectid +
977 block_group->key.offset)
978 break;
979
980 extent_start = max(extent_start, start);
981 extent_end = min(block_group->key.objectid +
982 block_group->key.offset, extent_end + 1);
983 len = extent_end - extent_start;
984
985 entries++;
986 ret = io_ctl_add_entry(&io_ctl, extent_start, len, NULL);
987 if (ret)
988 goto out_nospc;
989
990 start = extent_end;
991 }
992
993 /* Write out the bitmaps */
994 list_for_each_safe(pos, n, &bitmap_list) {
995 struct btrfs_free_space *entry =
996 list_entry(pos, struct btrfs_free_space, list);
997
998 ret = io_ctl_add_bitmap(&io_ctl, entry->bitmap);
999 if (ret)
1000 goto out_nospc;
1001 list_del_init(&entry->list);
1002 }
1003
1004 /* Zero out the rest of the pages just to make sure */
1005 io_ctl_zero_remaining_pages(&io_ctl);
1006
1007 ret = btrfs_dirty_pages(root, inode, io_ctl.pages, io_ctl.num_pages,
1008 0, i_size_read(inode), &cached_state);
1009 io_ctl_drop_pages(&io_ctl);
1010 unlock_extent_cached(&BTRFS_I(inode)->io_tree, 0,
1011 i_size_read(inode) - 1, &cached_state, GFP_NOFS);
1012
1013 if (ret)
1014 goto out;
1015
1016
1017 btrfs_wait_ordered_range(inode, 0, (u64)-1);
1018
1019 key.objectid = BTRFS_FREE_SPACE_OBJECTID;
1020 key.offset = offset;
1021 key.type = 0;
1022
1023 ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
1024 if (ret < 0) {
1025 clear_extent_bit(&BTRFS_I(inode)->io_tree, 0, inode->i_size - 1,
1026 EXTENT_DIRTY | EXTENT_DELALLOC, 0, 0, NULL,
1027 GFP_NOFS);
1028 goto out;
1029 }
1030 leaf = path->nodes[0];
1031 if (ret > 0) {
1032 struct btrfs_key found_key;
1033 BUG_ON(!path->slots[0]);
1034 path->slots[0]--;
1035 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
1036 if (found_key.objectid != BTRFS_FREE_SPACE_OBJECTID ||
1037 found_key.offset != offset) {
1038 clear_extent_bit(&BTRFS_I(inode)->io_tree, 0,
1039 inode->i_size - 1,
1040 EXTENT_DIRTY | EXTENT_DELALLOC, 0, 0,
1041 NULL, GFP_NOFS);
1042 btrfs_release_path(path);
1043 goto out;
1044 }
1045 }
1046
1047 BTRFS_I(inode)->generation = trans->transid;
1048 header = btrfs_item_ptr(leaf, path->slots[0],
1049 struct btrfs_free_space_header);
1050 btrfs_set_free_space_entries(leaf, header, entries);
1051 btrfs_set_free_space_bitmaps(leaf, header, bitmaps);
1052 btrfs_set_free_space_generation(leaf, header, trans->transid);
1053 btrfs_mark_buffer_dirty(leaf);
1054 btrfs_release_path(path);
1055
1056 err = 0;
1057 out:
1058 io_ctl_free(&io_ctl);
1059 if (err) {
1060 invalidate_inode_pages2(inode->i_mapping);
1061 BTRFS_I(inode)->generation = 0;
1062 }
1063 btrfs_update_inode(trans, root, inode);
1064 return err;
1065
1066 out_nospc:
1067 list_for_each_safe(pos, n, &bitmap_list) {
1068 struct btrfs_free_space *entry =
1069 list_entry(pos, struct btrfs_free_space, list);
1070 list_del_init(&entry->list);
1071 }
1072 io_ctl_drop_pages(&io_ctl);
1073 unlock_extent_cached(&BTRFS_I(inode)->io_tree, 0,
1074 i_size_read(inode) - 1, &cached_state, GFP_NOFS);
1075 goto out;
1076 }
1077
1078 int btrfs_write_out_cache(struct btrfs_root *root,
1079 struct btrfs_trans_handle *trans,
1080 struct btrfs_block_group_cache *block_group,
1081 struct btrfs_path *path)
1082 {
1083 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
1084 struct inode *inode;
1085 int ret = 0;
1086
1087 root = root->fs_info->tree_root;
1088
1089 spin_lock(&block_group->lock);
1090 if (block_group->disk_cache_state < BTRFS_DC_SETUP) {
1091 spin_unlock(&block_group->lock);
1092 return 0;
1093 }
1094 spin_unlock(&block_group->lock);
1095
1096 inode = lookup_free_space_inode(root, block_group, path);
1097 if (IS_ERR(inode))
1098 return 0;
1099
1100 ret = __btrfs_write_out_cache(root, inode, ctl, block_group, trans,
1101 path, block_group->key.objectid);
1102 if (ret) {
1103 spin_lock(&block_group->lock);
1104 block_group->disk_cache_state = BTRFS_DC_ERROR;
1105 spin_unlock(&block_group->lock);
1106 ret = 0;
1107 #ifdef DEBUG
1108 printk(KERN_ERR "btrfs: failed to write free space cache "
1109 "for block group %llu\n", 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 = &entry->offset_index;
1254 while (1) {
1255 n = rb_prev(n);
1256 if (!n)
1257 break;
1258 prev = rb_entry(n, struct btrfs_free_space,
1259 offset_index);
1260 if (!prev->bitmap) {
1261 if (prev->offset + prev->bytes > offset)
1262 entry = prev;
1263 break;
1264 }
1265 }
1266 }
1267 return entry;
1268 }
1269
1270 if (!prev)
1271 return NULL;
1272
1273 /* find last entry before the 'offset' */
1274 entry = prev;
1275 if (entry->offset > offset) {
1276 n = rb_prev(&entry->offset_index);
1277 if (n) {
1278 entry = rb_entry(n, struct btrfs_free_space,
1279 offset_index);
1280 BUG_ON(entry->offset > offset);
1281 } else {
1282 if (fuzzy)
1283 return entry;
1284 else
1285 return NULL;
1286 }
1287 }
1288
1289 if (entry->bitmap) {
1290 n = &entry->offset_index;
1291 while (1) {
1292 n = rb_prev(n);
1293 if (!n)
1294 break;
1295 prev = rb_entry(n, struct btrfs_free_space,
1296 offset_index);
1297 if (!prev->bitmap) {
1298 if (prev->offset + prev->bytes > offset)
1299 return prev;
1300 break;
1301 }
1302 }
1303 if (entry->offset + BITS_PER_BITMAP * ctl->unit > offset)
1304 return entry;
1305 } else if (entry->offset + entry->bytes > offset)
1306 return entry;
1307
1308 if (!fuzzy)
1309 return NULL;
1310
1311 while (1) {
1312 if (entry->bitmap) {
1313 if (entry->offset + BITS_PER_BITMAP *
1314 ctl->unit > offset)
1315 break;
1316 } else {
1317 if (entry->offset + entry->bytes > offset)
1318 break;
1319 }
1320
1321 n = rb_next(&entry->offset_index);
1322 if (!n)
1323 return NULL;
1324 entry = rb_entry(n, struct btrfs_free_space, offset_index);
1325 }
1326 return entry;
1327 }
1328
1329 static inline void
1330 __unlink_free_space(struct btrfs_free_space_ctl *ctl,
1331 struct btrfs_free_space *info)
1332 {
1333 rb_erase(&info->offset_index, &ctl->free_space_offset);
1334 ctl->free_extents--;
1335 }
1336
1337 static void unlink_free_space(struct btrfs_free_space_ctl *ctl,
1338 struct btrfs_free_space *info)
1339 {
1340 __unlink_free_space(ctl, info);
1341 ctl->free_space -= info->bytes;
1342 }
1343
1344 static int link_free_space(struct btrfs_free_space_ctl *ctl,
1345 struct btrfs_free_space *info)
1346 {
1347 int ret = 0;
1348
1349 BUG_ON(!info->bitmap && !info->bytes);
1350 ret = tree_insert_offset(&ctl->free_space_offset, info->offset,
1351 &info->offset_index, (info->bitmap != NULL));
1352 if (ret)
1353 return ret;
1354
1355 ctl->free_space += info->bytes;
1356 ctl->free_extents++;
1357 return ret;
1358 }
1359
1360 static void recalculate_thresholds(struct btrfs_free_space_ctl *ctl)
1361 {
1362 struct btrfs_block_group_cache *block_group = ctl->private;
1363 u64 max_bytes;
1364 u64 bitmap_bytes;
1365 u64 extent_bytes;
1366 u64 size = block_group->key.offset;
1367 u64 bytes_per_bg = BITS_PER_BITMAP * block_group->sectorsize;
1368 int max_bitmaps = div64_u64(size + bytes_per_bg - 1, bytes_per_bg);
1369
1370 BUG_ON(ctl->total_bitmaps > max_bitmaps);
1371
1372 /*
1373 * The goal is to keep the total amount of memory used per 1gb of space
1374 * at or below 32k, so we need to adjust how much memory we allow to be
1375 * used by extent based free space tracking
1376 */
1377 if (size < 1024 * 1024 * 1024)
1378 max_bytes = MAX_CACHE_BYTES_PER_GIG;
1379 else
1380 max_bytes = MAX_CACHE_BYTES_PER_GIG *
1381 div64_u64(size, 1024 * 1024 * 1024);
1382
1383 /*
1384 * we want to account for 1 more bitmap than what we have so we can make
1385 * sure we don't go over our overall goal of MAX_CACHE_BYTES_PER_GIG as
1386 * we add more bitmaps.
1387 */
1388 bitmap_bytes = (ctl->total_bitmaps + 1) * PAGE_CACHE_SIZE;
1389
1390 if (bitmap_bytes >= max_bytes) {
1391 ctl->extents_thresh = 0;
1392 return;
1393 }
1394
1395 /*
1396 * we want the extent entry threshold to always be at most 1/2 the maxw
1397 * bytes we can have, or whatever is less than that.
1398 */
1399 extent_bytes = max_bytes - bitmap_bytes;
1400 extent_bytes = min_t(u64, extent_bytes, div64_u64(max_bytes, 2));
1401
1402 ctl->extents_thresh =
1403 div64_u64(extent_bytes, (sizeof(struct btrfs_free_space)));
1404 }
1405
1406 static inline void __bitmap_clear_bits(struct btrfs_free_space_ctl *ctl,
1407 struct btrfs_free_space *info,
1408 u64 offset, u64 bytes)
1409 {
1410 unsigned long start, count;
1411
1412 start = offset_to_bit(info->offset, ctl->unit, offset);
1413 count = bytes_to_bits(bytes, ctl->unit);
1414 BUG_ON(start + count > BITS_PER_BITMAP);
1415
1416 bitmap_clear(info->bitmap, start, count);
1417
1418 info->bytes -= bytes;
1419 }
1420
1421 static void bitmap_clear_bits(struct btrfs_free_space_ctl *ctl,
1422 struct btrfs_free_space *info, u64 offset,
1423 u64 bytes)
1424 {
1425 __bitmap_clear_bits(ctl, info, offset, bytes);
1426 ctl->free_space -= bytes;
1427 }
1428
1429 static void bitmap_set_bits(struct btrfs_free_space_ctl *ctl,
1430 struct btrfs_free_space *info, u64 offset,
1431 u64 bytes)
1432 {
1433 unsigned long start, count;
1434
1435 start = offset_to_bit(info->offset, ctl->unit, offset);
1436 count = bytes_to_bits(bytes, ctl->unit);
1437 BUG_ON(start + count > BITS_PER_BITMAP);
1438
1439 bitmap_set(info->bitmap, start, count);
1440
1441 info->bytes += bytes;
1442 ctl->free_space += bytes;
1443 }
1444
1445 static int search_bitmap(struct btrfs_free_space_ctl *ctl,
1446 struct btrfs_free_space *bitmap_info, u64 *offset,
1447 u64 *bytes)
1448 {
1449 unsigned long found_bits = 0;
1450 unsigned long bits, i;
1451 unsigned long next_zero;
1452
1453 i = offset_to_bit(bitmap_info->offset, ctl->unit,
1454 max_t(u64, *offset, bitmap_info->offset));
1455 bits = bytes_to_bits(*bytes, ctl->unit);
1456
1457 for (i = find_next_bit(bitmap_info->bitmap, BITS_PER_BITMAP, i);
1458 i < BITS_PER_BITMAP;
1459 i = find_next_bit(bitmap_info->bitmap, BITS_PER_BITMAP, i + 1)) {
1460 next_zero = find_next_zero_bit(bitmap_info->bitmap,
1461 BITS_PER_BITMAP, i);
1462 if ((next_zero - i) >= bits) {
1463 found_bits = next_zero - i;
1464 break;
1465 }
1466 i = next_zero;
1467 }
1468
1469 if (found_bits) {
1470 *offset = (u64)(i * ctl->unit) + bitmap_info->offset;
1471 *bytes = (u64)(found_bits) * ctl->unit;
1472 return 0;
1473 }
1474
1475 return -1;
1476 }
1477
1478 static struct btrfs_free_space *
1479 find_free_space(struct btrfs_free_space_ctl *ctl, u64 *offset, u64 *bytes)
1480 {
1481 struct btrfs_free_space *entry;
1482 struct rb_node *node;
1483 int ret;
1484
1485 if (!ctl->free_space_offset.rb_node)
1486 return NULL;
1487
1488 entry = tree_search_offset(ctl, offset_to_bitmap(ctl, *offset), 0, 1);
1489 if (!entry)
1490 return NULL;
1491
1492 for (node = &entry->offset_index; node; node = rb_next(node)) {
1493 entry = rb_entry(node, struct btrfs_free_space, offset_index);
1494 if (entry->bytes < *bytes)
1495 continue;
1496
1497 if (entry->bitmap) {
1498 ret = search_bitmap(ctl, entry, offset, bytes);
1499 if (!ret)
1500 return entry;
1501 continue;
1502 }
1503
1504 *offset = entry->offset;
1505 *bytes = entry->bytes;
1506 return entry;
1507 }
1508
1509 return NULL;
1510 }
1511
1512 static void add_new_bitmap(struct btrfs_free_space_ctl *ctl,
1513 struct btrfs_free_space *info, u64 offset)
1514 {
1515 info->offset = offset_to_bitmap(ctl, offset);
1516 info->bytes = 0;
1517 INIT_LIST_HEAD(&info->list);
1518 link_free_space(ctl, info);
1519 ctl->total_bitmaps++;
1520
1521 ctl->op->recalc_thresholds(ctl);
1522 }
1523
1524 static void free_bitmap(struct btrfs_free_space_ctl *ctl,
1525 struct btrfs_free_space *bitmap_info)
1526 {
1527 unlink_free_space(ctl, bitmap_info);
1528 kfree(bitmap_info->bitmap);
1529 kmem_cache_free(btrfs_free_space_cachep, bitmap_info);
1530 ctl->total_bitmaps--;
1531 ctl->op->recalc_thresholds(ctl);
1532 }
1533
1534 static noinline int remove_from_bitmap(struct btrfs_free_space_ctl *ctl,
1535 struct btrfs_free_space *bitmap_info,
1536 u64 *offset, u64 *bytes)
1537 {
1538 u64 end;
1539 u64 search_start, search_bytes;
1540 int ret;
1541
1542 again:
1543 end = bitmap_info->offset + (u64)(BITS_PER_BITMAP * ctl->unit) - 1;
1544
1545 /*
1546 * We need to search for bits in this bitmap. We could only cover some
1547 * of the extent in this bitmap thanks to how we add space, so we need
1548 * to search for as much as it as we can and clear that amount, and then
1549 * go searching for the next bit.
1550 */
1551 search_start = *offset;
1552 search_bytes = ctl->unit;
1553 search_bytes = min(search_bytes, end - search_start + 1);
1554 ret = search_bitmap(ctl, bitmap_info, &search_start, &search_bytes);
1555 BUG_ON(ret < 0 || search_start != *offset);
1556
1557 /* We may have found more bits than what we need */
1558 search_bytes = min(search_bytes, *bytes);
1559
1560 /* Cannot clear past the end of the bitmap */
1561 search_bytes = min(search_bytes, end - search_start + 1);
1562
1563 bitmap_clear_bits(ctl, bitmap_info, search_start, search_bytes);
1564 *offset += search_bytes;
1565 *bytes -= search_bytes;
1566
1567 if (*bytes) {
1568 struct rb_node *next = rb_next(&bitmap_info->offset_index);
1569 if (!bitmap_info->bytes)
1570 free_bitmap(ctl, bitmap_info);
1571
1572 /*
1573 * no entry after this bitmap, but we still have bytes to
1574 * remove, so something has gone wrong.
1575 */
1576 if (!next)
1577 return -EINVAL;
1578
1579 bitmap_info = rb_entry(next, struct btrfs_free_space,
1580 offset_index);
1581
1582 /*
1583 * if the next entry isn't a bitmap we need to return to let the
1584 * extent stuff do its work.
1585 */
1586 if (!bitmap_info->bitmap)
1587 return -EAGAIN;
1588
1589 /*
1590 * Ok the next item is a bitmap, but it may not actually hold
1591 * the information for the rest of this free space stuff, so
1592 * look for it, and if we don't find it return so we can try
1593 * everything over again.
1594 */
1595 search_start = *offset;
1596 search_bytes = ctl->unit;
1597 ret = search_bitmap(ctl, bitmap_info, &search_start,
1598 &search_bytes);
1599 if (ret < 0 || search_start != *offset)
1600 return -EAGAIN;
1601
1602 goto again;
1603 } else if (!bitmap_info->bytes)
1604 free_bitmap(ctl, bitmap_info);
1605
1606 return 0;
1607 }
1608
1609 static u64 add_bytes_to_bitmap(struct btrfs_free_space_ctl *ctl,
1610 struct btrfs_free_space *info, u64 offset,
1611 u64 bytes)
1612 {
1613 u64 bytes_to_set = 0;
1614 u64 end;
1615
1616 end = info->offset + (u64)(BITS_PER_BITMAP * ctl->unit);
1617
1618 bytes_to_set = min(end - offset, bytes);
1619
1620 bitmap_set_bits(ctl, info, offset, bytes_to_set);
1621
1622 return bytes_to_set;
1623
1624 }
1625
1626 static bool use_bitmap(struct btrfs_free_space_ctl *ctl,
1627 struct btrfs_free_space *info)
1628 {
1629 struct btrfs_block_group_cache *block_group = ctl->private;
1630
1631 /*
1632 * If we are below the extents threshold then we can add this as an
1633 * extent, and don't have to deal with the bitmap
1634 */
1635 if (ctl->free_extents < ctl->extents_thresh) {
1636 /*
1637 * If this block group has some small extents we don't want to
1638 * use up all of our free slots in the cache with them, we want
1639 * to reserve them to larger extents, however if we have plent
1640 * of cache left then go ahead an dadd them, no sense in adding
1641 * the overhead of a bitmap if we don't have to.
1642 */
1643 if (info->bytes <= block_group->sectorsize * 4) {
1644 if (ctl->free_extents * 2 <= ctl->extents_thresh)
1645 return false;
1646 } else {
1647 return false;
1648 }
1649 }
1650
1651 /*
1652 * some block groups are so tiny they can't be enveloped by a bitmap, so
1653 * don't even bother to create a bitmap for this
1654 */
1655 if (BITS_PER_BITMAP * block_group->sectorsize >
1656 block_group->key.offset)
1657 return false;
1658
1659 return true;
1660 }
1661
1662 static struct btrfs_free_space_op free_space_op = {
1663 .recalc_thresholds = recalculate_thresholds,
1664 .use_bitmap = use_bitmap,
1665 };
1666
1667 static int insert_into_bitmap(struct btrfs_free_space_ctl *ctl,
1668 struct btrfs_free_space *info)
1669 {
1670 struct btrfs_free_space *bitmap_info;
1671 struct btrfs_block_group_cache *block_group = NULL;
1672 int added = 0;
1673 u64 bytes, offset, bytes_added;
1674 int ret;
1675
1676 bytes = info->bytes;
1677 offset = info->offset;
1678
1679 if (!ctl->op->use_bitmap(ctl, info))
1680 return 0;
1681
1682 if (ctl->op == &free_space_op)
1683 block_group = ctl->private;
1684 again:
1685 /*
1686 * Since we link bitmaps right into the cluster we need to see if we
1687 * have a cluster here, and if so and it has our bitmap we need to add
1688 * the free space to that bitmap.
1689 */
1690 if (block_group && !list_empty(&block_group->cluster_list)) {
1691 struct btrfs_free_cluster *cluster;
1692 struct rb_node *node;
1693 struct btrfs_free_space *entry;
1694
1695 cluster = list_entry(block_group->cluster_list.next,
1696 struct btrfs_free_cluster,
1697 block_group_list);
1698 spin_lock(&cluster->lock);
1699 node = rb_first(&cluster->root);
1700 if (!node) {
1701 spin_unlock(&cluster->lock);
1702 goto no_cluster_bitmap;
1703 }
1704
1705 entry = rb_entry(node, struct btrfs_free_space, offset_index);
1706 if (!entry->bitmap) {
1707 spin_unlock(&cluster->lock);
1708 goto no_cluster_bitmap;
1709 }
1710
1711 if (entry->offset == offset_to_bitmap(ctl, offset)) {
1712 bytes_added = add_bytes_to_bitmap(ctl, entry,
1713 offset, bytes);
1714 bytes -= bytes_added;
1715 offset += bytes_added;
1716 }
1717 spin_unlock(&cluster->lock);
1718 if (!bytes) {
1719 ret = 1;
1720 goto out;
1721 }
1722 }
1723
1724 no_cluster_bitmap:
1725 bitmap_info = tree_search_offset(ctl, offset_to_bitmap(ctl, offset),
1726 1, 0);
1727 if (!bitmap_info) {
1728 BUG_ON(added);
1729 goto new_bitmap;
1730 }
1731
1732 bytes_added = add_bytes_to_bitmap(ctl, bitmap_info, offset, bytes);
1733 bytes -= bytes_added;
1734 offset += bytes_added;
1735 added = 0;
1736
1737 if (!bytes) {
1738 ret = 1;
1739 goto out;
1740 } else
1741 goto again;
1742
1743 new_bitmap:
1744 if (info && info->bitmap) {
1745 add_new_bitmap(ctl, info, offset);
1746 added = 1;
1747 info = NULL;
1748 goto again;
1749 } else {
1750 spin_unlock(&ctl->tree_lock);
1751
1752 /* no pre-allocated info, allocate a new one */
1753 if (!info) {
1754 info = kmem_cache_zalloc(btrfs_free_space_cachep,
1755 GFP_NOFS);
1756 if (!info) {
1757 spin_lock(&ctl->tree_lock);
1758 ret = -ENOMEM;
1759 goto out;
1760 }
1761 }
1762
1763 /* allocate the bitmap */
1764 info->bitmap = kzalloc(PAGE_CACHE_SIZE, GFP_NOFS);
1765 spin_lock(&ctl->tree_lock);
1766 if (!info->bitmap) {
1767 ret = -ENOMEM;
1768 goto out;
1769 }
1770 goto again;
1771 }
1772
1773 out:
1774 if (info) {
1775 if (info->bitmap)
1776 kfree(info->bitmap);
1777 kmem_cache_free(btrfs_free_space_cachep, info);
1778 }
1779
1780 return ret;
1781 }
1782
1783 static bool try_merge_free_space(struct btrfs_free_space_ctl *ctl,
1784 struct btrfs_free_space *info, bool update_stat)
1785 {
1786 struct btrfs_free_space *left_info;
1787 struct btrfs_free_space *right_info;
1788 bool merged = false;
1789 u64 offset = info->offset;
1790 u64 bytes = info->bytes;
1791
1792 /*
1793 * first we want to see if there is free space adjacent to the range we
1794 * are adding, if there is remove that struct and add a new one to
1795 * cover the entire range
1796 */
1797 right_info = tree_search_offset(ctl, offset + bytes, 0, 0);
1798 if (right_info && rb_prev(&right_info->offset_index))
1799 left_info = rb_entry(rb_prev(&right_info->offset_index),
1800 struct btrfs_free_space, offset_index);
1801 else
1802 left_info = tree_search_offset(ctl, offset - 1, 0, 0);
1803
1804 if (right_info && !right_info->bitmap) {
1805 if (update_stat)
1806 unlink_free_space(ctl, right_info);
1807 else
1808 __unlink_free_space(ctl, right_info);
1809 info->bytes += right_info->bytes;
1810 kmem_cache_free(btrfs_free_space_cachep, right_info);
1811 merged = true;
1812 }
1813
1814 if (left_info && !left_info->bitmap &&
1815 left_info->offset + left_info->bytes == offset) {
1816 if (update_stat)
1817 unlink_free_space(ctl, left_info);
1818 else
1819 __unlink_free_space(ctl, left_info);
1820 info->offset = left_info->offset;
1821 info->bytes += left_info->bytes;
1822 kmem_cache_free(btrfs_free_space_cachep, left_info);
1823 merged = true;
1824 }
1825
1826 return merged;
1827 }
1828
1829 int __btrfs_add_free_space(struct btrfs_free_space_ctl *ctl,
1830 u64 offset, u64 bytes)
1831 {
1832 struct btrfs_free_space *info;
1833 int ret = 0;
1834
1835 info = kmem_cache_zalloc(btrfs_free_space_cachep, GFP_NOFS);
1836 if (!info)
1837 return -ENOMEM;
1838
1839 info->offset = offset;
1840 info->bytes = bytes;
1841
1842 spin_lock(&ctl->tree_lock);
1843
1844 if (try_merge_free_space(ctl, info, true))
1845 goto link;
1846
1847 /*
1848 * There was no extent directly to the left or right of this new
1849 * extent then we know we're going to have to allocate a new extent, so
1850 * before we do that see if we need to drop this into a bitmap
1851 */
1852 ret = insert_into_bitmap(ctl, info);
1853 if (ret < 0) {
1854 goto out;
1855 } else if (ret) {
1856 ret = 0;
1857 goto out;
1858 }
1859 link:
1860 ret = link_free_space(ctl, info);
1861 if (ret)
1862 kmem_cache_free(btrfs_free_space_cachep, info);
1863 out:
1864 spin_unlock(&ctl->tree_lock);
1865
1866 if (ret) {
1867 printk(KERN_CRIT "btrfs: unable to add free space :%d\n", ret);
1868 BUG_ON(ret == -EEXIST);
1869 }
1870
1871 return ret;
1872 }
1873
1874 int btrfs_remove_free_space(struct btrfs_block_group_cache *block_group,
1875 u64 offset, u64 bytes)
1876 {
1877 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
1878 struct btrfs_free_space *info;
1879 int ret = 0;
1880
1881 spin_lock(&ctl->tree_lock);
1882
1883 again:
1884 if (!bytes)
1885 goto out_lock;
1886
1887 info = tree_search_offset(ctl, offset, 0, 0);
1888 if (!info) {
1889 /*
1890 * oops didn't find an extent that matched the space we wanted
1891 * to remove, look for a bitmap instead
1892 */
1893 info = tree_search_offset(ctl, offset_to_bitmap(ctl, offset),
1894 1, 0);
1895 if (!info) {
1896 /* the tree logging code might be calling us before we
1897 * have fully loaded the free space rbtree for this
1898 * block group. So it is possible the entry won't
1899 * be in the rbtree yet at all. The caching code
1900 * will make sure not to put it in the rbtree if
1901 * the logging code has pinned it.
1902 */
1903 goto out_lock;
1904 }
1905 }
1906
1907 if (!info->bitmap) {
1908 unlink_free_space(ctl, info);
1909 if (offset == info->offset) {
1910 u64 to_free = min(bytes, info->bytes);
1911
1912 info->bytes -= to_free;
1913 info->offset += to_free;
1914 if (info->bytes) {
1915 ret = link_free_space(ctl, info);
1916 WARN_ON(ret);
1917 } else {
1918 kmem_cache_free(btrfs_free_space_cachep, info);
1919 }
1920
1921 offset += to_free;
1922 bytes -= to_free;
1923 goto again;
1924 } else {
1925 u64 old_end = info->bytes + info->offset;
1926
1927 info->bytes = offset - info->offset;
1928 ret = link_free_space(ctl, info);
1929 WARN_ON(ret);
1930 if (ret)
1931 goto out_lock;
1932
1933 /* Not enough bytes in this entry to satisfy us */
1934 if (old_end < offset + bytes) {
1935 bytes -= old_end - offset;
1936 offset = old_end;
1937 goto again;
1938 } else if (old_end == offset + bytes) {
1939 /* all done */
1940 goto out_lock;
1941 }
1942 spin_unlock(&ctl->tree_lock);
1943
1944 ret = btrfs_add_free_space(block_group, offset + bytes,
1945 old_end - (offset + bytes));
1946 WARN_ON(ret);
1947 goto out;
1948 }
1949 }
1950
1951 ret = remove_from_bitmap(ctl, info, &offset, &bytes);
1952 if (ret == -EAGAIN)
1953 goto again;
1954 BUG_ON(ret); /* logic error */
1955 out_lock:
1956 spin_unlock(&ctl->tree_lock);
1957 out:
1958 return ret;
1959 }
1960
1961 void btrfs_dump_free_space(struct btrfs_block_group_cache *block_group,
1962 u64 bytes)
1963 {
1964 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
1965 struct btrfs_free_space *info;
1966 struct rb_node *n;
1967 int count = 0;
1968
1969 for (n = rb_first(&ctl->free_space_offset); n; n = rb_next(n)) {
1970 info = rb_entry(n, struct btrfs_free_space, offset_index);
1971 if (info->bytes >= bytes)
1972 count++;
1973 printk(KERN_CRIT "entry offset %llu, bytes %llu, bitmap %s\n",
1974 (unsigned long long)info->offset,
1975 (unsigned long long)info->bytes,
1976 (info->bitmap) ? "yes" : "no");
1977 }
1978 printk(KERN_INFO "block group has cluster?: %s\n",
1979 list_empty(&block_group->cluster_list) ? "no" : "yes");
1980 printk(KERN_INFO "%d blocks of free space at or bigger than bytes is"
1981 "\n", count);
1982 }
1983
1984 void btrfs_init_free_space_ctl(struct btrfs_block_group_cache *block_group)
1985 {
1986 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
1987
1988 spin_lock_init(&ctl->tree_lock);
1989 ctl->unit = block_group->sectorsize;
1990 ctl->start = block_group->key.objectid;
1991 ctl->private = block_group;
1992 ctl->op = &free_space_op;
1993
1994 /*
1995 * we only want to have 32k of ram per block group for keeping
1996 * track of free space, and if we pass 1/2 of that we want to
1997 * start converting things over to using bitmaps
1998 */
1999 ctl->extents_thresh = ((1024 * 32) / 2) /
2000 sizeof(struct btrfs_free_space);
2001 }
2002
2003 /*
2004 * for a given cluster, put all of its extents back into the free
2005 * space cache. If the block group passed doesn't match the block group
2006 * pointed to by the cluster, someone else raced in and freed the
2007 * cluster already. In that case, we just return without changing anything
2008 */
2009 static int
2010 __btrfs_return_cluster_to_free_space(
2011 struct btrfs_block_group_cache *block_group,
2012 struct btrfs_free_cluster *cluster)
2013 {
2014 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2015 struct btrfs_free_space *entry;
2016 struct rb_node *node;
2017
2018 spin_lock(&cluster->lock);
2019 if (cluster->block_group != block_group)
2020 goto out;
2021
2022 cluster->block_group = NULL;
2023 cluster->window_start = 0;
2024 list_del_init(&cluster->block_group_list);
2025
2026 node = rb_first(&cluster->root);
2027 while (node) {
2028 bool bitmap;
2029
2030 entry = rb_entry(node, struct btrfs_free_space, offset_index);
2031 node = rb_next(&entry->offset_index);
2032 rb_erase(&entry->offset_index, &cluster->root);
2033
2034 bitmap = (entry->bitmap != NULL);
2035 if (!bitmap)
2036 try_merge_free_space(ctl, entry, false);
2037 tree_insert_offset(&ctl->free_space_offset,
2038 entry->offset, &entry->offset_index, bitmap);
2039 }
2040 cluster->root = RB_ROOT;
2041
2042 out:
2043 spin_unlock(&cluster->lock);
2044 btrfs_put_block_group(block_group);
2045 return 0;
2046 }
2047
2048 void __btrfs_remove_free_space_cache_locked(struct btrfs_free_space_ctl *ctl)
2049 {
2050 struct btrfs_free_space *info;
2051 struct rb_node *node;
2052
2053 while ((node = rb_last(&ctl->free_space_offset)) != NULL) {
2054 info = rb_entry(node, struct btrfs_free_space, offset_index);
2055 if (!info->bitmap) {
2056 unlink_free_space(ctl, info);
2057 kmem_cache_free(btrfs_free_space_cachep, info);
2058 } else {
2059 free_bitmap(ctl, info);
2060 }
2061 if (need_resched()) {
2062 spin_unlock(&ctl->tree_lock);
2063 cond_resched();
2064 spin_lock(&ctl->tree_lock);
2065 }
2066 }
2067 }
2068
2069 void __btrfs_remove_free_space_cache(struct btrfs_free_space_ctl *ctl)
2070 {
2071 spin_lock(&ctl->tree_lock);
2072 __btrfs_remove_free_space_cache_locked(ctl);
2073 spin_unlock(&ctl->tree_lock);
2074 }
2075
2076 void btrfs_remove_free_space_cache(struct btrfs_block_group_cache *block_group)
2077 {
2078 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2079 struct btrfs_free_cluster *cluster;
2080 struct list_head *head;
2081
2082 spin_lock(&ctl->tree_lock);
2083 while ((head = block_group->cluster_list.next) !=
2084 &block_group->cluster_list) {
2085 cluster = list_entry(head, struct btrfs_free_cluster,
2086 block_group_list);
2087
2088 WARN_ON(cluster->block_group != block_group);
2089 __btrfs_return_cluster_to_free_space(block_group, cluster);
2090 if (need_resched()) {
2091 spin_unlock(&ctl->tree_lock);
2092 cond_resched();
2093 spin_lock(&ctl->tree_lock);
2094 }
2095 }
2096 __btrfs_remove_free_space_cache_locked(ctl);
2097 spin_unlock(&ctl->tree_lock);
2098
2099 }
2100
2101 u64 btrfs_find_space_for_alloc(struct btrfs_block_group_cache *block_group,
2102 u64 offset, u64 bytes, u64 empty_size)
2103 {
2104 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2105 struct btrfs_free_space *entry = NULL;
2106 u64 bytes_search = bytes + empty_size;
2107 u64 ret = 0;
2108
2109 spin_lock(&ctl->tree_lock);
2110 entry = find_free_space(ctl, &offset, &bytes_search);
2111 if (!entry)
2112 goto out;
2113
2114 ret = offset;
2115 if (entry->bitmap) {
2116 bitmap_clear_bits(ctl, entry, offset, bytes);
2117 if (!entry->bytes)
2118 free_bitmap(ctl, entry);
2119 } else {
2120 unlink_free_space(ctl, entry);
2121 entry->offset += bytes;
2122 entry->bytes -= bytes;
2123 if (!entry->bytes)
2124 kmem_cache_free(btrfs_free_space_cachep, entry);
2125 else
2126 link_free_space(ctl, entry);
2127 }
2128
2129 out:
2130 spin_unlock(&ctl->tree_lock);
2131
2132 return ret;
2133 }
2134
2135 /*
2136 * given a cluster, put all of its extents back into the free space
2137 * cache. If a block group is passed, this function will only free
2138 * a cluster that belongs to the passed block group.
2139 *
2140 * Otherwise, it'll get a reference on the block group pointed to by the
2141 * cluster and remove the cluster from it.
2142 */
2143 int btrfs_return_cluster_to_free_space(
2144 struct btrfs_block_group_cache *block_group,
2145 struct btrfs_free_cluster *cluster)
2146 {
2147 struct btrfs_free_space_ctl *ctl;
2148 int ret;
2149
2150 /* first, get a safe pointer to the block group */
2151 spin_lock(&cluster->lock);
2152 if (!block_group) {
2153 block_group = cluster->block_group;
2154 if (!block_group) {
2155 spin_unlock(&cluster->lock);
2156 return 0;
2157 }
2158 } else if (cluster->block_group != block_group) {
2159 /* someone else has already freed it don't redo their work */
2160 spin_unlock(&cluster->lock);
2161 return 0;
2162 }
2163 atomic_inc(&block_group->count);
2164 spin_unlock(&cluster->lock);
2165
2166 ctl = block_group->free_space_ctl;
2167
2168 /* now return any extents the cluster had on it */
2169 spin_lock(&ctl->tree_lock);
2170 ret = __btrfs_return_cluster_to_free_space(block_group, cluster);
2171 spin_unlock(&ctl->tree_lock);
2172
2173 /* finally drop our ref */
2174 btrfs_put_block_group(block_group);
2175 return ret;
2176 }
2177
2178 static u64 btrfs_alloc_from_bitmap(struct btrfs_block_group_cache *block_group,
2179 struct btrfs_free_cluster *cluster,
2180 struct btrfs_free_space *entry,
2181 u64 bytes, u64 min_start)
2182 {
2183 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2184 int err;
2185 u64 search_start = cluster->window_start;
2186 u64 search_bytes = bytes;
2187 u64 ret = 0;
2188
2189 search_start = min_start;
2190 search_bytes = bytes;
2191
2192 err = search_bitmap(ctl, entry, &search_start, &search_bytes);
2193 if (err)
2194 return 0;
2195
2196 ret = search_start;
2197 __bitmap_clear_bits(ctl, entry, ret, bytes);
2198
2199 return ret;
2200 }
2201
2202 /*
2203 * given a cluster, try to allocate 'bytes' from it, returns 0
2204 * if it couldn't find anything suitably large, or a logical disk offset
2205 * if things worked out
2206 */
2207 u64 btrfs_alloc_from_cluster(struct btrfs_block_group_cache *block_group,
2208 struct btrfs_free_cluster *cluster, u64 bytes,
2209 u64 min_start)
2210 {
2211 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2212 struct btrfs_free_space *entry = NULL;
2213 struct rb_node *node;
2214 u64 ret = 0;
2215
2216 spin_lock(&cluster->lock);
2217 if (bytes > cluster->max_size)
2218 goto out;
2219
2220 if (cluster->block_group != block_group)
2221 goto out;
2222
2223 node = rb_first(&cluster->root);
2224 if (!node)
2225 goto out;
2226
2227 entry = rb_entry(node, struct btrfs_free_space, offset_index);
2228 while(1) {
2229 if (entry->bytes < bytes ||
2230 (!entry->bitmap && entry->offset < min_start)) {
2231 node = rb_next(&entry->offset_index);
2232 if (!node)
2233 break;
2234 entry = rb_entry(node, struct btrfs_free_space,
2235 offset_index);
2236 continue;
2237 }
2238
2239 if (entry->bitmap) {
2240 ret = btrfs_alloc_from_bitmap(block_group,
2241 cluster, entry, bytes,
2242 cluster->window_start);
2243 if (ret == 0) {
2244 node = rb_next(&entry->offset_index);
2245 if (!node)
2246 break;
2247 entry = rb_entry(node, struct btrfs_free_space,
2248 offset_index);
2249 continue;
2250 }
2251 cluster->window_start += bytes;
2252 } else {
2253 ret = entry->offset;
2254
2255 entry->offset += bytes;
2256 entry->bytes -= bytes;
2257 }
2258
2259 if (entry->bytes == 0)
2260 rb_erase(&entry->offset_index, &cluster->root);
2261 break;
2262 }
2263 out:
2264 spin_unlock(&cluster->lock);
2265
2266 if (!ret)
2267 return 0;
2268
2269 spin_lock(&ctl->tree_lock);
2270
2271 ctl->free_space -= bytes;
2272 if (entry->bytes == 0) {
2273 ctl->free_extents--;
2274 if (entry->bitmap) {
2275 kfree(entry->bitmap);
2276 ctl->total_bitmaps--;
2277 ctl->op->recalc_thresholds(ctl);
2278 }
2279 kmem_cache_free(btrfs_free_space_cachep, entry);
2280 }
2281
2282 spin_unlock(&ctl->tree_lock);
2283
2284 return ret;
2285 }
2286
2287 static int btrfs_bitmap_cluster(struct btrfs_block_group_cache *block_group,
2288 struct btrfs_free_space *entry,
2289 struct btrfs_free_cluster *cluster,
2290 u64 offset, u64 bytes,
2291 u64 cont1_bytes, u64 min_bytes)
2292 {
2293 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2294 unsigned long next_zero;
2295 unsigned long i;
2296 unsigned long want_bits;
2297 unsigned long min_bits;
2298 unsigned long found_bits;
2299 unsigned long start = 0;
2300 unsigned long total_found = 0;
2301 int ret;
2302
2303 i = offset_to_bit(entry->offset, block_group->sectorsize,
2304 max_t(u64, offset, entry->offset));
2305 want_bits = bytes_to_bits(bytes, block_group->sectorsize);
2306 min_bits = bytes_to_bits(min_bytes, block_group->sectorsize);
2307
2308 again:
2309 found_bits = 0;
2310 for (i = find_next_bit(entry->bitmap, BITS_PER_BITMAP, i);
2311 i < BITS_PER_BITMAP;
2312 i = find_next_bit(entry->bitmap, BITS_PER_BITMAP, i + 1)) {
2313 next_zero = find_next_zero_bit(entry->bitmap,
2314 BITS_PER_BITMAP, i);
2315 if (next_zero - i >= min_bits) {
2316 found_bits = next_zero - i;
2317 break;
2318 }
2319 i = next_zero;
2320 }
2321
2322 if (!found_bits)
2323 return -ENOSPC;
2324
2325 if (!total_found) {
2326 start = i;
2327 cluster->max_size = 0;
2328 }
2329
2330 total_found += found_bits;
2331
2332 if (cluster->max_size < found_bits * block_group->sectorsize)
2333 cluster->max_size = found_bits * block_group->sectorsize;
2334
2335 if (total_found < want_bits || cluster->max_size < cont1_bytes) {
2336 i = next_zero + 1;
2337 goto again;
2338 }
2339
2340 cluster->window_start = start * block_group->sectorsize +
2341 entry->offset;
2342 rb_erase(&entry->offset_index, &ctl->free_space_offset);
2343 ret = tree_insert_offset(&cluster->root, entry->offset,
2344 &entry->offset_index, 1);
2345 BUG_ON(ret); /* -EEXIST; Logic error */
2346
2347 trace_btrfs_setup_cluster(block_group, cluster,
2348 total_found * block_group->sectorsize, 1);
2349 return 0;
2350 }
2351
2352 /*
2353 * This searches the block group for just extents to fill the cluster with.
2354 * Try to find a cluster with at least bytes total bytes, at least one
2355 * extent of cont1_bytes, and other clusters of at least min_bytes.
2356 */
2357 static noinline int
2358 setup_cluster_no_bitmap(struct btrfs_block_group_cache *block_group,
2359 struct btrfs_free_cluster *cluster,
2360 struct list_head *bitmaps, u64 offset, u64 bytes,
2361 u64 cont1_bytes, u64 min_bytes)
2362 {
2363 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2364 struct btrfs_free_space *first = NULL;
2365 struct btrfs_free_space *entry = NULL;
2366 struct btrfs_free_space *last;
2367 struct rb_node *node;
2368 u64 window_start;
2369 u64 window_free;
2370 u64 max_extent;
2371 u64 total_size = 0;
2372
2373 entry = tree_search_offset(ctl, offset, 0, 1);
2374 if (!entry)
2375 return -ENOSPC;
2376
2377 /*
2378 * We don't want bitmaps, so just move along until we find a normal
2379 * extent entry.
2380 */
2381 while (entry->bitmap || entry->bytes < min_bytes) {
2382 if (entry->bitmap && list_empty(&entry->list))
2383 list_add_tail(&entry->list, bitmaps);
2384 node = rb_next(&entry->offset_index);
2385 if (!node)
2386 return -ENOSPC;
2387 entry = rb_entry(node, struct btrfs_free_space, offset_index);
2388 }
2389
2390 window_start = entry->offset;
2391 window_free = entry->bytes;
2392 max_extent = entry->bytes;
2393 first = entry;
2394 last = entry;
2395
2396 for (node = rb_next(&entry->offset_index); node;
2397 node = rb_next(&entry->offset_index)) {
2398 entry = rb_entry(node, struct btrfs_free_space, offset_index);
2399
2400 if (entry->bitmap) {
2401 if (list_empty(&entry->list))
2402 list_add_tail(&entry->list, bitmaps);
2403 continue;
2404 }
2405
2406 if (entry->bytes < min_bytes)
2407 continue;
2408
2409 last = entry;
2410 window_free += entry->bytes;
2411 if (entry->bytes > max_extent)
2412 max_extent = entry->bytes;
2413 }
2414
2415 if (window_free < bytes || max_extent < cont1_bytes)
2416 return -ENOSPC;
2417
2418 cluster->window_start = first->offset;
2419
2420 node = &first->offset_index;
2421
2422 /*
2423 * now we've found our entries, pull them out of the free space
2424 * cache and put them into the cluster rbtree
2425 */
2426 do {
2427 int ret;
2428
2429 entry = rb_entry(node, struct btrfs_free_space, offset_index);
2430 node = rb_next(&entry->offset_index);
2431 if (entry->bitmap || entry->bytes < min_bytes)
2432 continue;
2433
2434 rb_erase(&entry->offset_index, &ctl->free_space_offset);
2435 ret = tree_insert_offset(&cluster->root, entry->offset,
2436 &entry->offset_index, 0);
2437 total_size += entry->bytes;
2438 BUG_ON(ret); /* -EEXIST; Logic error */
2439 } while (node && entry != last);
2440
2441 cluster->max_size = max_extent;
2442 trace_btrfs_setup_cluster(block_group, cluster, total_size, 0);
2443 return 0;
2444 }
2445
2446 /*
2447 * This specifically looks for bitmaps that may work in the cluster, we assume
2448 * that we have already failed to find extents that will work.
2449 */
2450 static noinline int
2451 setup_cluster_bitmap(struct btrfs_block_group_cache *block_group,
2452 struct btrfs_free_cluster *cluster,
2453 struct list_head *bitmaps, u64 offset, u64 bytes,
2454 u64 cont1_bytes, u64 min_bytes)
2455 {
2456 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2457 struct btrfs_free_space *entry;
2458 int ret = -ENOSPC;
2459 u64 bitmap_offset = offset_to_bitmap(ctl, offset);
2460
2461 if (ctl->total_bitmaps == 0)
2462 return -ENOSPC;
2463
2464 /*
2465 * The bitmap that covers offset won't be in the list unless offset
2466 * is just its start offset.
2467 */
2468 entry = list_first_entry(bitmaps, struct btrfs_free_space, list);
2469 if (entry->offset != bitmap_offset) {
2470 entry = tree_search_offset(ctl, bitmap_offset, 1, 0);
2471 if (entry && list_empty(&entry->list))
2472 list_add(&entry->list, bitmaps);
2473 }
2474
2475 list_for_each_entry(entry, bitmaps, list) {
2476 if (entry->bytes < bytes)
2477 continue;
2478 ret = btrfs_bitmap_cluster(block_group, entry, cluster, offset,
2479 bytes, cont1_bytes, min_bytes);
2480 if (!ret)
2481 return 0;
2482 }
2483
2484 /*
2485 * The bitmaps list has all the bitmaps that record free space
2486 * starting after offset, so no more search is required.
2487 */
2488 return -ENOSPC;
2489 }
2490
2491 /*
2492 * here we try to find a cluster of blocks in a block group. The goal
2493 * is to find at least bytes+empty_size.
2494 * We might not find them all in one contiguous area.
2495 *
2496 * returns zero and sets up cluster if things worked out, otherwise
2497 * it returns -enospc
2498 */
2499 int btrfs_find_space_cluster(struct btrfs_trans_handle *trans,
2500 struct btrfs_root *root,
2501 struct btrfs_block_group_cache *block_group,
2502 struct btrfs_free_cluster *cluster,
2503 u64 offset, u64 bytes, u64 empty_size)
2504 {
2505 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2506 struct btrfs_free_space *entry, *tmp;
2507 LIST_HEAD(bitmaps);
2508 u64 min_bytes;
2509 u64 cont1_bytes;
2510 int ret;
2511
2512 /*
2513 * Choose the minimum extent size we'll require for this
2514 * cluster. For SSD_SPREAD, don't allow any fragmentation.
2515 * For metadata, allow allocates with smaller extents. For
2516 * data, keep it dense.
2517 */
2518 if (btrfs_test_opt(root, SSD_SPREAD)) {
2519 cont1_bytes = min_bytes = bytes + empty_size;
2520 } else if (block_group->flags & BTRFS_BLOCK_GROUP_METADATA) {
2521 cont1_bytes = bytes;
2522 min_bytes = block_group->sectorsize;
2523 } else {
2524 cont1_bytes = max(bytes, (bytes + empty_size) >> 2);
2525 min_bytes = block_group->sectorsize;
2526 }
2527
2528 spin_lock(&ctl->tree_lock);
2529
2530 /*
2531 * If we know we don't have enough space to make a cluster don't even
2532 * bother doing all the work to try and find one.
2533 */
2534 if (ctl->free_space < bytes) {
2535 spin_unlock(&ctl->tree_lock);
2536 return -ENOSPC;
2537 }
2538
2539 spin_lock(&cluster->lock);
2540
2541 /* someone already found a cluster, hooray */
2542 if (cluster->block_group) {
2543 ret = 0;
2544 goto out;
2545 }
2546
2547 trace_btrfs_find_cluster(block_group, offset, bytes, empty_size,
2548 min_bytes);
2549
2550 INIT_LIST_HEAD(&bitmaps);
2551 ret = setup_cluster_no_bitmap(block_group, cluster, &bitmaps, offset,
2552 bytes + empty_size,
2553 cont1_bytes, min_bytes);
2554 if (ret)
2555 ret = setup_cluster_bitmap(block_group, cluster, &bitmaps,
2556 offset, bytes + empty_size,
2557 cont1_bytes, min_bytes);
2558
2559 /* Clear our temporary list */
2560 list_for_each_entry_safe(entry, tmp, &bitmaps, list)
2561 list_del_init(&entry->list);
2562
2563 if (!ret) {
2564 atomic_inc(&block_group->count);
2565 list_add_tail(&cluster->block_group_list,
2566 &block_group->cluster_list);
2567 cluster->block_group = block_group;
2568 } else {
2569 trace_btrfs_failed_cluster_setup(block_group);
2570 }
2571 out:
2572 spin_unlock(&cluster->lock);
2573 spin_unlock(&ctl->tree_lock);
2574
2575 return ret;
2576 }
2577
2578 /*
2579 * simple code to zero out a cluster
2580 */
2581 void btrfs_init_free_cluster(struct btrfs_free_cluster *cluster)
2582 {
2583 spin_lock_init(&cluster->lock);
2584 spin_lock_init(&cluster->refill_lock);
2585 cluster->root = RB_ROOT;
2586 cluster->max_size = 0;
2587 INIT_LIST_HEAD(&cluster->block_group_list);
2588 cluster->block_group = NULL;
2589 }
2590
2591 static int do_trimming(struct btrfs_block_group_cache *block_group,
2592 u64 *total_trimmed, u64 start, u64 bytes,
2593 u64 reserved_start, u64 reserved_bytes)
2594 {
2595 struct btrfs_space_info *space_info = block_group->space_info;
2596 struct btrfs_fs_info *fs_info = block_group->fs_info;
2597 int ret;
2598 int update = 0;
2599 u64 trimmed = 0;
2600
2601 spin_lock(&space_info->lock);
2602 spin_lock(&block_group->lock);
2603 if (!block_group->ro) {
2604 block_group->reserved += reserved_bytes;
2605 space_info->bytes_reserved += reserved_bytes;
2606 update = 1;
2607 }
2608 spin_unlock(&block_group->lock);
2609 spin_unlock(&space_info->lock);
2610
2611 ret = btrfs_error_discard_extent(fs_info->extent_root,
2612 start, bytes, &trimmed);
2613 if (!ret)
2614 *total_trimmed += trimmed;
2615
2616 btrfs_add_free_space(block_group, reserved_start, reserved_bytes);
2617
2618 if (update) {
2619 spin_lock(&space_info->lock);
2620 spin_lock(&block_group->lock);
2621 if (block_group->ro)
2622 space_info->bytes_readonly += reserved_bytes;
2623 block_group->reserved -= reserved_bytes;
2624 space_info->bytes_reserved -= reserved_bytes;
2625 spin_unlock(&space_info->lock);
2626 spin_unlock(&block_group->lock);
2627 }
2628
2629 return ret;
2630 }
2631
2632 static int trim_no_bitmap(struct btrfs_block_group_cache *block_group,
2633 u64 *total_trimmed, u64 start, u64 end, u64 minlen)
2634 {
2635 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2636 struct btrfs_free_space *entry;
2637 struct rb_node *node;
2638 int ret = 0;
2639 u64 extent_start;
2640 u64 extent_bytes;
2641 u64 bytes;
2642
2643 while (start < end) {
2644 spin_lock(&ctl->tree_lock);
2645
2646 if (ctl->free_space < minlen) {
2647 spin_unlock(&ctl->tree_lock);
2648 break;
2649 }
2650
2651 entry = tree_search_offset(ctl, start, 0, 1);
2652 if (!entry) {
2653 spin_unlock(&ctl->tree_lock);
2654 break;
2655 }
2656
2657 /* skip bitmaps */
2658 while (entry->bitmap) {
2659 node = rb_next(&entry->offset_index);
2660 if (!node) {
2661 spin_unlock(&ctl->tree_lock);
2662 goto out;
2663 }
2664 entry = rb_entry(node, struct btrfs_free_space,
2665 offset_index);
2666 }
2667
2668 if (entry->offset >= end) {
2669 spin_unlock(&ctl->tree_lock);
2670 break;
2671 }
2672
2673 extent_start = entry->offset;
2674 extent_bytes = entry->bytes;
2675 start = max(start, extent_start);
2676 bytes = min(extent_start + extent_bytes, end) - start;
2677 if (bytes < minlen) {
2678 spin_unlock(&ctl->tree_lock);
2679 goto next;
2680 }
2681
2682 unlink_free_space(ctl, entry);
2683 kmem_cache_free(btrfs_free_space_cachep, entry);
2684
2685 spin_unlock(&ctl->tree_lock);
2686
2687 ret = do_trimming(block_group, total_trimmed, start, bytes,
2688 extent_start, extent_bytes);
2689 if (ret)
2690 break;
2691 next:
2692 start += bytes;
2693
2694 if (fatal_signal_pending(current)) {
2695 ret = -ERESTARTSYS;
2696 break;
2697 }
2698
2699 cond_resched();
2700 }
2701 out:
2702 return ret;
2703 }
2704
2705 static int trim_bitmaps(struct btrfs_block_group_cache *block_group,
2706 u64 *total_trimmed, u64 start, u64 end, u64 minlen)
2707 {
2708 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2709 struct btrfs_free_space *entry;
2710 int ret = 0;
2711 int ret2;
2712 u64 bytes;
2713 u64 offset = offset_to_bitmap(ctl, start);
2714
2715 while (offset < end) {
2716 bool next_bitmap = false;
2717
2718 spin_lock(&ctl->tree_lock);
2719
2720 if (ctl->free_space < minlen) {
2721 spin_unlock(&ctl->tree_lock);
2722 break;
2723 }
2724
2725 entry = tree_search_offset(ctl, offset, 1, 0);
2726 if (!entry) {
2727 spin_unlock(&ctl->tree_lock);
2728 next_bitmap = true;
2729 goto next;
2730 }
2731
2732 bytes = minlen;
2733 ret2 = search_bitmap(ctl, entry, &start, &bytes);
2734 if (ret2 || start >= end) {
2735 spin_unlock(&ctl->tree_lock);
2736 next_bitmap = true;
2737 goto next;
2738 }
2739
2740 bytes = min(bytes, end - start);
2741 if (bytes < minlen) {
2742 spin_unlock(&ctl->tree_lock);
2743 goto next;
2744 }
2745
2746 bitmap_clear_bits(ctl, entry, start, bytes);
2747 if (entry->bytes == 0)
2748 free_bitmap(ctl, entry);
2749
2750 spin_unlock(&ctl->tree_lock);
2751
2752 ret = do_trimming(block_group, total_trimmed, start, bytes,
2753 start, bytes);
2754 if (ret)
2755 break;
2756 next:
2757 if (next_bitmap) {
2758 offset += BITS_PER_BITMAP * ctl->unit;
2759 } else {
2760 start += bytes;
2761 if (start >= offset + BITS_PER_BITMAP * ctl->unit)
2762 offset += BITS_PER_BITMAP * ctl->unit;
2763 }
2764
2765 if (fatal_signal_pending(current)) {
2766 ret = -ERESTARTSYS;
2767 break;
2768 }
2769
2770 cond_resched();
2771 }
2772
2773 return ret;
2774 }
2775
2776 int btrfs_trim_block_group(struct btrfs_block_group_cache *block_group,
2777 u64 *trimmed, u64 start, u64 end, u64 minlen)
2778 {
2779 int ret;
2780
2781 *trimmed = 0;
2782
2783 ret = trim_no_bitmap(block_group, trimmed, start, end, minlen);
2784 if (ret)
2785 return ret;
2786
2787 ret = trim_bitmaps(block_group, trimmed, start, end, minlen);
2788
2789 return ret;
2790 }
2791
2792 /*
2793 * Find the left-most item in the cache tree, and then return the
2794 * smallest inode number in the item.
2795 *
2796 * Note: the returned inode number may not be the smallest one in
2797 * the tree, if the left-most item is a bitmap.
2798 */
2799 u64 btrfs_find_ino_for_alloc(struct btrfs_root *fs_root)
2800 {
2801 struct btrfs_free_space_ctl *ctl = fs_root->free_ino_ctl;
2802 struct btrfs_free_space *entry = NULL;
2803 u64 ino = 0;
2804
2805 spin_lock(&ctl->tree_lock);
2806
2807 if (RB_EMPTY_ROOT(&ctl->free_space_offset))
2808 goto out;
2809
2810 entry = rb_entry(rb_first(&ctl->free_space_offset),
2811 struct btrfs_free_space, offset_index);
2812
2813 if (!entry->bitmap) {
2814 ino = entry->offset;
2815
2816 unlink_free_space(ctl, entry);
2817 entry->offset++;
2818 entry->bytes--;
2819 if (!entry->bytes)
2820 kmem_cache_free(btrfs_free_space_cachep, entry);
2821 else
2822 link_free_space(ctl, entry);
2823 } else {
2824 u64 offset = 0;
2825 u64 count = 1;
2826 int ret;
2827
2828 ret = search_bitmap(ctl, entry, &offset, &count);
2829 /* Logic error; Should be empty if it can't find anything */
2830 BUG_ON(ret);
2831
2832 ino = offset;
2833 bitmap_clear_bits(ctl, entry, offset, 1);
2834 if (entry->bytes == 0)
2835 free_bitmap(ctl, entry);
2836 }
2837 out:
2838 spin_unlock(&ctl->tree_lock);
2839
2840 return ino;
2841 }
2842
2843 struct inode *lookup_free_ino_inode(struct btrfs_root *root,
2844 struct btrfs_path *path)
2845 {
2846 struct inode *inode = NULL;
2847
2848 spin_lock(&root->cache_lock);
2849 if (root->cache_inode)
2850 inode = igrab(root->cache_inode);
2851 spin_unlock(&root->cache_lock);
2852 if (inode)
2853 return inode;
2854
2855 inode = __lookup_free_space_inode(root, path, 0);
2856 if (IS_ERR(inode))
2857 return inode;
2858
2859 spin_lock(&root->cache_lock);
2860 if (!btrfs_fs_closing(root->fs_info))
2861 root->cache_inode = igrab(inode);
2862 spin_unlock(&root->cache_lock);
2863
2864 return inode;
2865 }
2866
2867 int create_free_ino_inode(struct btrfs_root *root,
2868 struct btrfs_trans_handle *trans,
2869 struct btrfs_path *path)
2870 {
2871 return __create_free_space_inode(root, trans, path,
2872 BTRFS_FREE_INO_OBJECTID, 0);
2873 }
2874
2875 int load_free_ino_cache(struct btrfs_fs_info *fs_info, struct btrfs_root *root)
2876 {
2877 struct btrfs_free_space_ctl *ctl = root->free_ino_ctl;
2878 struct btrfs_path *path;
2879 struct inode *inode;
2880 int ret = 0;
2881 u64 root_gen = btrfs_root_generation(&root->root_item);
2882
2883 if (!btrfs_test_opt(root, INODE_MAP_CACHE))
2884 return 0;
2885
2886 /*
2887 * If we're unmounting then just return, since this does a search on the
2888 * normal root and not the commit root and we could deadlock.
2889 */
2890 if (btrfs_fs_closing(fs_info))
2891 return 0;
2892
2893 path = btrfs_alloc_path();
2894 if (!path)
2895 return 0;
2896
2897 inode = lookup_free_ino_inode(root, path);
2898 if (IS_ERR(inode))
2899 goto out;
2900
2901 if (root_gen != BTRFS_I(inode)->generation)
2902 goto out_put;
2903
2904 ret = __load_free_space_cache(root, inode, ctl, path, 0);
2905
2906 if (ret < 0)
2907 printk(KERN_ERR "btrfs: failed to load free ino cache for "
2908 "root %llu\n", root->root_key.objectid);
2909 out_put:
2910 iput(inode);
2911 out:
2912 btrfs_free_path(path);
2913 return ret;
2914 }
2915
2916 int btrfs_write_out_ino_cache(struct btrfs_root *root,
2917 struct btrfs_trans_handle *trans,
2918 struct btrfs_path *path)
2919 {
2920 struct btrfs_free_space_ctl *ctl = root->free_ino_ctl;
2921 struct inode *inode;
2922 int ret;
2923
2924 if (!btrfs_test_opt(root, INODE_MAP_CACHE))
2925 return 0;
2926
2927 inode = lookup_free_ino_inode(root, path);
2928 if (IS_ERR(inode))
2929 return 0;
2930
2931 ret = __btrfs_write_out_cache(root, inode, ctl, NULL, trans, path, 0);
2932 if (ret) {
2933 btrfs_delalloc_release_metadata(inode, inode->i_size);
2934 #ifdef DEBUG
2935 printk(KERN_ERR "btrfs: failed to write free ino cache "
2936 "for root %llu\n", root->root_key.objectid);
2937 #endif
2938 }
2939
2940 iput(inode);
2941 return ret;
2942 }
Linus' kernel tree