projects / deliverable / linux.git / blob
? search:
summary | shortlog | log | commit | commitdiff | tree
blame | history | raw | HEAD
Btrfs: avoid possible NULL deref in io_ctl_drop_pages()
[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
37 static struct inode *__lookup_free_space_inode(struct btrfs_root *root,
38 struct btrfs_path *path,
39 u64 offset)
40 {
41 struct btrfs_key key;
42 struct btrfs_key location;
43 struct btrfs_disk_key disk_key;
44 struct btrfs_free_space_header *header;
45 struct extent_buffer *leaf;
46 struct inode *inode = NULL;
47 int ret;
48
49 key.objectid = BTRFS_FREE_SPACE_OBJECTID;
50 key.offset = offset;
51 key.type = 0;
52
53 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
54 if (ret < 0)
55 return ERR_PTR(ret);
56 if (ret > 0) {
57 btrfs_release_path(path);
58 return ERR_PTR(-ENOENT);
59 }
60
61 leaf = path->nodes[0];
62 header = btrfs_item_ptr(leaf, path->slots[0],
63 struct btrfs_free_space_header);
64 btrfs_free_space_key(leaf, header, &disk_key);
65 btrfs_disk_key_to_cpu(&location, &disk_key);
66 btrfs_release_path(path);
67
68 inode = btrfs_iget(root->fs_info->sb, &location, root, NULL);
69 if (!inode)
70 return ERR_PTR(-ENOENT);
71 if (IS_ERR(inode))
72 return inode;
73 if (is_bad_inode(inode)) {
74 iput(inode);
75 return ERR_PTR(-ENOENT);
76 }
77
78 inode->i_mapping->flags &= ~__GFP_FS;
79
80 return inode;
81 }
82
83 struct inode *lookup_free_space_inode(struct btrfs_root *root,
84 struct btrfs_block_group_cache
85 *block_group, struct btrfs_path *path)
86 {
87 struct inode *inode = NULL;
88 u32 flags = BTRFS_INODE_NODATASUM | BTRFS_INODE_NODATACOW;
89
90 spin_lock(&block_group->lock);
91 if (block_group->inode)
92 inode = igrab(block_group->inode);
93 spin_unlock(&block_group->lock);
94 if (inode)
95 return inode;
96
97 inode = __lookup_free_space_inode(root, path,
98 block_group->key.objectid);
99 if (IS_ERR(inode))
100 return inode;
101
102 spin_lock(&block_group->lock);
103 if (!((BTRFS_I(inode)->flags & flags) == flags)) {
104 printk(KERN_INFO "Old style space inode found, converting.\n");
105 BTRFS_I(inode)->flags |= BTRFS_INODE_NODATASUM |
106 BTRFS_INODE_NODATACOW;
107 block_group->disk_cache_state = BTRFS_DC_CLEAR;
108 }
109
110 if (!block_group->iref) {
111 block_group->inode = igrab(inode);
112 block_group->iref = 1;
113 }
114 spin_unlock(&block_group->lock);
115
116 return inode;
117 }
118
119 int __create_free_space_inode(struct btrfs_root *root,
120 struct btrfs_trans_handle *trans,
121 struct btrfs_path *path, u64 ino, u64 offset)
122 {
123 struct btrfs_key key;
124 struct btrfs_disk_key disk_key;
125 struct btrfs_free_space_header *header;
126 struct btrfs_inode_item *inode_item;
127 struct extent_buffer *leaf;
128 u64 flags = BTRFS_INODE_NOCOMPRESS | BTRFS_INODE_PREALLOC;
129 int ret;
130
131 ret = btrfs_insert_empty_inode(trans, root, path, ino);
132 if (ret)
133 return ret;
134
135 /* We inline crc's for the free disk space cache */
136 if (ino != BTRFS_FREE_INO_OBJECTID)
137 flags |= BTRFS_INODE_NODATASUM | BTRFS_INODE_NODATACOW;
138
139 leaf = path->nodes[0];
140 inode_item = btrfs_item_ptr(leaf, path->slots[0],
141 struct btrfs_inode_item);
142 btrfs_item_key(leaf, &disk_key, path->slots[0]);
143 memset_extent_buffer(leaf, 0, (unsigned long)inode_item,
144 sizeof(*inode_item));
145 btrfs_set_inode_generation(leaf, inode_item, trans->transid);
146 btrfs_set_inode_size(leaf, inode_item, 0);
147 btrfs_set_inode_nbytes(leaf, inode_item, 0);
148 btrfs_set_inode_uid(leaf, inode_item, 0);
149 btrfs_set_inode_gid(leaf, inode_item, 0);
150 btrfs_set_inode_mode(leaf, inode_item, S_IFREG | 0600);
151 btrfs_set_inode_flags(leaf, inode_item, flags);
152 btrfs_set_inode_nlink(leaf, inode_item, 1);
153 btrfs_set_inode_transid(leaf, inode_item, trans->transid);
154 btrfs_set_inode_block_group(leaf, inode_item, offset);
155 btrfs_mark_buffer_dirty(leaf);
156 btrfs_release_path(path);
157
158 key.objectid = BTRFS_FREE_SPACE_OBJECTID;
159 key.offset = offset;
160 key.type = 0;
161
162 ret = btrfs_insert_empty_item(trans, root, path, &key,
163 sizeof(struct btrfs_free_space_header));
164 if (ret < 0) {
165 btrfs_release_path(path);
166 return ret;
167 }
168 leaf = path->nodes[0];
169 header = btrfs_item_ptr(leaf, path->slots[0],
170 struct btrfs_free_space_header);
171 memset_extent_buffer(leaf, 0, (unsigned long)header, sizeof(*header));
172 btrfs_set_free_space_key(leaf, header, &disk_key);
173 btrfs_mark_buffer_dirty(leaf);
174 btrfs_release_path(path);
175
176 return 0;
177 }
178
179 int create_free_space_inode(struct btrfs_root *root,
180 struct btrfs_trans_handle *trans,
181 struct btrfs_block_group_cache *block_group,
182 struct btrfs_path *path)
183 {
184 int ret;
185 u64 ino;
186
187 ret = btrfs_find_free_objectid(root, &ino);
188 if (ret < 0)
189 return ret;
190
191 return __create_free_space_inode(root, trans, path, ino,
192 block_group->key.objectid);
193 }
194
195 int btrfs_truncate_free_space_cache(struct btrfs_root *root,
196 struct btrfs_trans_handle *trans,
197 struct btrfs_path *path,
198 struct inode *inode)
199 {
200 struct btrfs_block_rsv *rsv;
201 u64 needed_bytes;
202 loff_t oldsize;
203 int ret = 0;
204
205 rsv = trans->block_rsv;
206 trans->block_rsv = &root->fs_info->global_block_rsv;
207
208 /* 1 for slack space, 1 for updating the inode */
209 needed_bytes = btrfs_calc_trunc_metadata_size(root, 1) +
210 btrfs_calc_trans_metadata_size(root, 1);
211
212 spin_lock(&trans->block_rsv->lock);
213 if (trans->block_rsv->reserved < needed_bytes) {
214 spin_unlock(&trans->block_rsv->lock);
215 trans->block_rsv = rsv;
216 return -ENOSPC;
217 }
218 spin_unlock(&trans->block_rsv->lock);
219
220 oldsize = i_size_read(inode);
221 btrfs_i_size_write(inode, 0);
222 truncate_pagecache(inode, oldsize, 0);
223
224 /*
225 * We don't need an orphan item because truncating the free space cache
226 * will never be split across transactions.
227 */
228 ret = btrfs_truncate_inode_items(trans, root, inode,
229 0, BTRFS_EXTENT_DATA_KEY);
230
231 if (ret) {
232 trans->block_rsv = rsv;
233 WARN_ON(1);
234 return ret;
235 }
236
237 ret = btrfs_update_inode(trans, root, inode);
238 trans->block_rsv = rsv;
239
240 return ret;
241 }
242
243 static int readahead_cache(struct inode *inode)
244 {
245 struct file_ra_state *ra;
246 unsigned long last_index;
247
248 ra = kzalloc(sizeof(*ra), GFP_NOFS);
249 if (!ra)
250 return -ENOMEM;
251
252 file_ra_state_init(ra, inode->i_mapping);
253 last_index = (i_size_read(inode) - 1) >> PAGE_CACHE_SHIFT;
254
255 page_cache_sync_readahead(inode->i_mapping, ra, NULL, 0, last_index);
256
257 kfree(ra);
258
259 return 0;
260 }
261
262 struct io_ctl {
263 void *cur, *orig;
264 struct page *page;
265 struct page **pages;
266 struct btrfs_root *root;
267 unsigned long size;
268 int index;
269 int num_pages;
270 unsigned check_crcs:1;
271 };
272
273 static int io_ctl_init(struct io_ctl *io_ctl, struct inode *inode,
274 struct btrfs_root *root)
275 {
276 memset(io_ctl, 0, sizeof(struct io_ctl));
277 io_ctl->num_pages = (i_size_read(inode) + PAGE_CACHE_SIZE - 1) >>
278 PAGE_CACHE_SHIFT;
279 io_ctl->pages = kzalloc(sizeof(struct page *) * io_ctl->num_pages,
280 GFP_NOFS);
281 if (!io_ctl->pages)
282 return -ENOMEM;
283 io_ctl->root = root;
284 if (btrfs_ino(inode) != BTRFS_FREE_INO_OBJECTID)
285 io_ctl->check_crcs = 1;
286 return 0;
287 }
288
289 static void io_ctl_free(struct io_ctl *io_ctl)
290 {
291 kfree(io_ctl->pages);
292 }
293
294 static void io_ctl_unmap_page(struct io_ctl *io_ctl)
295 {
296 if (io_ctl->cur) {
297 kunmap(io_ctl->page);
298 io_ctl->cur = NULL;
299 io_ctl->orig = NULL;
300 }
301 }
302
303 static void io_ctl_map_page(struct io_ctl *io_ctl, int clear)
304 {
305 WARN_ON(io_ctl->cur);
306 BUG_ON(io_ctl->index >= io_ctl->num_pages);
307 io_ctl->page = io_ctl->pages[io_ctl->index++];
308 io_ctl->cur = kmap(io_ctl->page);
309 io_ctl->orig = io_ctl->cur;
310 io_ctl->size = PAGE_CACHE_SIZE;
311 if (clear)
312 memset(io_ctl->cur, 0, PAGE_CACHE_SIZE);
313 }
314
315 static void io_ctl_drop_pages(struct io_ctl *io_ctl)
316 {
317 int i;
318
319 io_ctl_unmap_page(io_ctl);
320
321 for (i = 0; i < io_ctl->num_pages; i++) {
322 if (io_ctl->pages[i]) {
323 ClearPageChecked(io_ctl->pages[i]);
324 unlock_page(io_ctl->pages[i]);
325 page_cache_release(io_ctl->pages[i]);
326 }
327 }
328 }
329
330 static int io_ctl_prepare_pages(struct io_ctl *io_ctl, struct inode *inode,
331 int uptodate)
332 {
333 struct page *page;
334 gfp_t mask = btrfs_alloc_write_mask(inode->i_mapping);
335 int i;
336
337 for (i = 0; i < io_ctl->num_pages; i++) {
338 page = find_or_create_page(inode->i_mapping, i, mask);
339 if (!page) {
340 io_ctl_drop_pages(io_ctl);
341 return -ENOMEM;
342 }
343 io_ctl->pages[i] = page;
344 if (uptodate && !PageUptodate(page)) {
345 btrfs_readpage(NULL, page);
346 lock_page(page);
347 if (!PageUptodate(page)) {
348 printk(KERN_ERR "btrfs: error reading free "
349 "space cache\n");
350 io_ctl_drop_pages(io_ctl);
351 return -EIO;
352 }
353 }
354 }
355
356 for (i = 0; i < io_ctl->num_pages; i++) {
357 clear_page_dirty_for_io(io_ctl->pages[i]);
358 set_page_extent_mapped(io_ctl->pages[i]);
359 }
360
361 return 0;
362 }
363
364 static void io_ctl_set_generation(struct io_ctl *io_ctl, u64 generation)
365 {
366 u64 *val;
367
368 io_ctl_map_page(io_ctl, 1);
369
370 /*
371 * Skip the csum areas. If we don't check crcs then we just have a
372 * 64bit chunk at the front of the first page.
373 */
374 if (io_ctl->check_crcs) {
375 io_ctl->cur += (sizeof(u32) * io_ctl->num_pages);
376 io_ctl->size -= sizeof(u64) + (sizeof(u32) * io_ctl->num_pages);
377 } else {
378 io_ctl->cur += sizeof(u64);
379 io_ctl->size -= sizeof(u64) * 2;
380 }
381
382 val = io_ctl->cur;
383 *val = cpu_to_le64(generation);
384 io_ctl->cur += sizeof(u64);
385 }
386
387 static int io_ctl_check_generation(struct io_ctl *io_ctl, u64 generation)
388 {
389 u64 *gen;
390
391 /*
392 * Skip the crc area. If we don't check crcs then we just have a 64bit
393 * chunk at the front of the first page.
394 */
395 if (io_ctl->check_crcs) {
396 io_ctl->cur += sizeof(u32) * io_ctl->num_pages;
397 io_ctl->size -= sizeof(u64) +
398 (sizeof(u32) * io_ctl->num_pages);
399 } else {
400 io_ctl->cur += sizeof(u64);
401 io_ctl->size -= sizeof(u64) * 2;
402 }
403
404 gen = io_ctl->cur;
405 if (le64_to_cpu(*gen) != generation) {
406 printk_ratelimited(KERN_ERR "btrfs: space cache generation "
407 "(%Lu) does not match inode (%Lu)\n", *gen,
408 generation);
409 io_ctl_unmap_page(io_ctl);
410 return -EIO;
411 }
412 io_ctl->cur += sizeof(u64);
413 return 0;
414 }
415
416 static void io_ctl_set_crc(struct io_ctl *io_ctl, int index)
417 {
418 u32 *tmp;
419 u32 crc = ~(u32)0;
420 unsigned offset = 0;
421
422 if (!io_ctl->check_crcs) {
423 io_ctl_unmap_page(io_ctl);
424 return;
425 }
426
427 if (index == 0)
428 offset = sizeof(u32) * io_ctl->num_pages;;
429
430 crc = btrfs_csum_data(io_ctl->root, io_ctl->orig + offset, crc,
431 PAGE_CACHE_SIZE - offset);
432 btrfs_csum_final(crc, (char *)&crc);
433 io_ctl_unmap_page(io_ctl);
434 tmp = kmap(io_ctl->pages[0]);
435 tmp += index;
436 *tmp = crc;
437 kunmap(io_ctl->pages[0]);
438 }
439
440 static int io_ctl_check_crc(struct io_ctl *io_ctl, int index)
441 {
442 u32 *tmp, val;
443 u32 crc = ~(u32)0;
444 unsigned offset = 0;
445
446 if (!io_ctl->check_crcs) {
447 io_ctl_map_page(io_ctl, 0);
448 return 0;
449 }
450
451 if (index == 0)
452 offset = sizeof(u32) * io_ctl->num_pages;
453
454 tmp = kmap(io_ctl->pages[0]);
455 tmp += index;
456 val = *tmp;
457 kunmap(io_ctl->pages[0]);
458
459 io_ctl_map_page(io_ctl, 0);
460 crc = btrfs_csum_data(io_ctl->root, io_ctl->orig + offset, crc,
461 PAGE_CACHE_SIZE - offset);
462 btrfs_csum_final(crc, (char *)&crc);
463 if (val != crc) {
464 printk_ratelimited(KERN_ERR "btrfs: csum mismatch on free "
465 "space cache\n");
466 io_ctl_unmap_page(io_ctl);
467 return -EIO;
468 }
469
470 return 0;
471 }
472
473 static int io_ctl_add_entry(struct io_ctl *io_ctl, u64 offset, u64 bytes,
474 void *bitmap)
475 {
476 struct btrfs_free_space_entry *entry;
477
478 if (!io_ctl->cur)
479 return -ENOSPC;
480
481 entry = io_ctl->cur;
482 entry->offset = cpu_to_le64(offset);
483 entry->bytes = cpu_to_le64(bytes);
484 entry->type = (bitmap) ? BTRFS_FREE_SPACE_BITMAP :
485 BTRFS_FREE_SPACE_EXTENT;
486 io_ctl->cur += sizeof(struct btrfs_free_space_entry);
487 io_ctl->size -= sizeof(struct btrfs_free_space_entry);
488
489 if (io_ctl->size >= sizeof(struct btrfs_free_space_entry))
490 return 0;
491
492 io_ctl_set_crc(io_ctl, io_ctl->index - 1);
493
494 /* No more pages to map */
495 if (io_ctl->index >= io_ctl->num_pages)
496 return 0;
497
498 /* map the next page */
499 io_ctl_map_page(io_ctl, 1);
500 return 0;
501 }
502
503 static int io_ctl_add_bitmap(struct io_ctl *io_ctl, void *bitmap)
504 {
505 if (!io_ctl->cur)
506 return -ENOSPC;
507
508 /*
509 * If we aren't at the start of the current page, unmap this one and
510 * map the next one if there is any left.
511 */
512 if (io_ctl->cur != io_ctl->orig) {
513 io_ctl_set_crc(io_ctl, io_ctl->index - 1);
514 if (io_ctl->index >= io_ctl->num_pages)
515 return -ENOSPC;
516 io_ctl_map_page(io_ctl, 0);
517 }
518
519 memcpy(io_ctl->cur, bitmap, PAGE_CACHE_SIZE);
520 io_ctl_set_crc(io_ctl, io_ctl->index - 1);
521 if (io_ctl->index < io_ctl->num_pages)
522 io_ctl_map_page(io_ctl, 0);
523 return 0;
524 }
525
526 static void io_ctl_zero_remaining_pages(struct io_ctl *io_ctl)
527 {
528 /*
529 * If we're not on the boundary we know we've modified the page and we
530 * need to crc the page.
531 */
532 if (io_ctl->cur != io_ctl->orig)
533 io_ctl_set_crc(io_ctl, io_ctl->index - 1);
534 else
535 io_ctl_unmap_page(io_ctl);
536
537 while (io_ctl->index < io_ctl->num_pages) {
538 io_ctl_map_page(io_ctl, 1);
539 io_ctl_set_crc(io_ctl, io_ctl->index - 1);
540 }
541 }
542
543 static int io_ctl_read_entry(struct io_ctl *io_ctl,
544 struct btrfs_free_space *entry, u8 *type)
545 {
546 struct btrfs_free_space_entry *e;
547 int ret;
548
549 if (!io_ctl->cur) {
550 ret = io_ctl_check_crc(io_ctl, io_ctl->index);
551 if (ret)
552 return ret;
553 }
554
555 e = io_ctl->cur;
556 entry->offset = le64_to_cpu(e->offset);
557 entry->bytes = le64_to_cpu(e->bytes);
558 *type = e->type;
559 io_ctl->cur += sizeof(struct btrfs_free_space_entry);
560 io_ctl->size -= sizeof(struct btrfs_free_space_entry);
561
562 if (io_ctl->size >= sizeof(struct btrfs_free_space_entry))
563 return 0;
564
565 io_ctl_unmap_page(io_ctl);
566
567 return 0;
568 }
569
570 static int io_ctl_read_bitmap(struct io_ctl *io_ctl,
571 struct btrfs_free_space *entry)
572 {
573 int ret;
574
575 ret = io_ctl_check_crc(io_ctl, io_ctl->index);
576 if (ret)
577 return ret;
578
579 memcpy(entry->bitmap, io_ctl->cur, PAGE_CACHE_SIZE);
580 io_ctl_unmap_page(io_ctl);
581
582 return 0;
583 }
584
585 int __load_free_space_cache(struct btrfs_root *root, struct inode *inode,
586 struct btrfs_free_space_ctl *ctl,
587 struct btrfs_path *path, u64 offset)
588 {
589 struct btrfs_free_space_header *header;
590 struct extent_buffer *leaf;
591 struct io_ctl io_ctl;
592 struct btrfs_key key;
593 struct btrfs_free_space *e, *n;
594 struct list_head bitmaps;
595 u64 num_entries;
596 u64 num_bitmaps;
597 u64 generation;
598 u8 type;
599 int ret = 0;
600
601 INIT_LIST_HEAD(&bitmaps);
602
603 /* Nothing in the space cache, goodbye */
604 if (!i_size_read(inode))
605 return 0;
606
607 key.objectid = BTRFS_FREE_SPACE_OBJECTID;
608 key.offset = offset;
609 key.type = 0;
610
611 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
612 if (ret < 0)
613 return 0;
614 else if (ret > 0) {
615 btrfs_release_path(path);
616 return 0;
617 }
618
619 ret = -1;
620
621 leaf = path->nodes[0];
622 header = btrfs_item_ptr(leaf, path->slots[0],
623 struct btrfs_free_space_header);
624 num_entries = btrfs_free_space_entries(leaf, header);
625 num_bitmaps = btrfs_free_space_bitmaps(leaf, header);
626 generation = btrfs_free_space_generation(leaf, header);
627 btrfs_release_path(path);
628
629 if (BTRFS_I(inode)->generation != generation) {
630 printk(KERN_ERR "btrfs: free space inode generation (%llu) did"
631 " not match free space cache generation (%llu)\n",
632 (unsigned long long)BTRFS_I(inode)->generation,
633 (unsigned long long)generation);
634 return 0;
635 }
636
637 if (!num_entries)
638 return 0;
639
640 io_ctl_init(&io_ctl, inode, root);
641 ret = readahead_cache(inode);
642 if (ret)
643 goto out;
644
645 ret = io_ctl_prepare_pages(&io_ctl, inode, 1);
646 if (ret)
647 goto out;
648
649 ret = io_ctl_check_crc(&io_ctl, 0);
650 if (ret)
651 goto free_cache;
652
653 ret = io_ctl_check_generation(&io_ctl, generation);
654 if (ret)
655 goto free_cache;
656
657 while (num_entries) {
658 e = kmem_cache_zalloc(btrfs_free_space_cachep,
659 GFP_NOFS);
660 if (!e)
661 goto free_cache;
662
663 ret = io_ctl_read_entry(&io_ctl, e, &type);
664 if (ret) {
665 kmem_cache_free(btrfs_free_space_cachep, e);
666 goto free_cache;
667 }
668
669 if (!e->bytes) {
670 kmem_cache_free(btrfs_free_space_cachep, e);
671 goto free_cache;
672 }
673
674 if (type == BTRFS_FREE_SPACE_EXTENT) {
675 spin_lock(&ctl->tree_lock);
676 ret = link_free_space(ctl, e);
677 spin_unlock(&ctl->tree_lock);
678 if (ret) {
679 printk(KERN_ERR "Duplicate entries in "
680 "free space cache, dumping\n");
681 kmem_cache_free(btrfs_free_space_cachep, e);
682 goto free_cache;
683 }
684 } else {
685 BUG_ON(!num_bitmaps);
686 num_bitmaps--;
687 e->bitmap = kzalloc(PAGE_CACHE_SIZE, GFP_NOFS);
688 if (!e->bitmap) {
689 kmem_cache_free(
690 btrfs_free_space_cachep, e);
691 goto free_cache;
692 }
693 spin_lock(&ctl->tree_lock);
694 ret = link_free_space(ctl, e);
695 ctl->total_bitmaps++;
696 ctl->op->recalc_thresholds(ctl);
697 spin_unlock(&ctl->tree_lock);
698 if (ret) {
699 printk(KERN_ERR "Duplicate entries in "
700 "free space cache, dumping\n");
701 kmem_cache_free(btrfs_free_space_cachep, e);
702 goto free_cache;
703 }
704 list_add_tail(&e->list, &bitmaps);
705 }
706
707 num_entries--;
708 }
709
710 io_ctl_unmap_page(&io_ctl);
711
712 /*
713 * We add the bitmaps at the end of the entries in order that
714 * the bitmap entries are added to the cache.
715 */
716 list_for_each_entry_safe(e, n, &bitmaps, list) {
717 list_del_init(&e->list);
718 ret = io_ctl_read_bitmap(&io_ctl, e);
719 if (ret)
720 goto free_cache;
721 }
722
723 io_ctl_drop_pages(&io_ctl);
724 ret = 1;
725 out:
726 io_ctl_free(&io_ctl);
727 return ret;
728 free_cache:
729 io_ctl_drop_pages(&io_ctl);
730 __btrfs_remove_free_space_cache(ctl);
731 goto out;
732 }
733
734 int load_free_space_cache(struct btrfs_fs_info *fs_info,
735 struct btrfs_block_group_cache *block_group)
736 {
737 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
738 struct btrfs_root *root = fs_info->tree_root;
739 struct inode *inode;
740 struct btrfs_path *path;
741 int ret = 0;
742 bool matched;
743 u64 used = btrfs_block_group_used(&block_group->item);
744
745 /*
746 * If we're unmounting then just return, since this does a search on the
747 * normal root and not the commit root and we could deadlock.
748 */
749 if (btrfs_fs_closing(fs_info))
750 return 0;
751
752 /*
753 * If this block group has been marked to be cleared for one reason or
754 * another then we can't trust the on disk cache, so just return.
755 */
756 spin_lock(&block_group->lock);
757 if (block_group->disk_cache_state != BTRFS_DC_WRITTEN) {
758 spin_unlock(&block_group->lock);
759 return 0;
760 }
761 spin_unlock(&block_group->lock);
762
763 path = btrfs_alloc_path();
764 if (!path)
765 return 0;
766
767 inode = lookup_free_space_inode(root, block_group, path);
768 if (IS_ERR(inode)) {
769 btrfs_free_path(path);
770 return 0;
771 }
772
773 /* We may have converted the inode and made the cache invalid. */
774 spin_lock(&block_group->lock);
775 if (block_group->disk_cache_state != BTRFS_DC_WRITTEN) {
776 spin_unlock(&block_group->lock);
777 goto out;
778 }
779 spin_unlock(&block_group->lock);
780
781 ret = __load_free_space_cache(fs_info->tree_root, inode, ctl,
782 path, block_group->key.objectid);
783 btrfs_free_path(path);
784 if (ret <= 0)
785 goto out;
786
787 spin_lock(&ctl->tree_lock);
788 matched = (ctl->free_space == (block_group->key.offset - used -
789 block_group->bytes_super));
790 spin_unlock(&ctl->tree_lock);
791
792 if (!matched) {
793 __btrfs_remove_free_space_cache(ctl);
794 printk(KERN_ERR "block group %llu has an wrong amount of free "
795 "space\n", block_group->key.objectid);
796 ret = -1;
797 }
798 out:
799 if (ret < 0) {
800 /* This cache is bogus, make sure it gets cleared */
801 spin_lock(&block_group->lock);
802 block_group->disk_cache_state = BTRFS_DC_CLEAR;
803 spin_unlock(&block_group->lock);
804 ret = 0;
805
806 printk(KERN_ERR "btrfs: failed to load free space cache "
807 "for block group %llu\n", block_group->key.objectid);
808 }
809
810 iput(inode);
811 return ret;
812 }
813
814 /**
815 * __btrfs_write_out_cache - write out cached info to an inode
816 * @root - the root the inode belongs to
817 * @ctl - the free space cache we are going to write out
818 * @block_group - the block_group for this cache if it belongs to a block_group
819 * @trans - the trans handle
820 * @path - the path to use
821 * @offset - the offset for the key we'll insert
822 *
823 * This function writes out a free space cache struct to disk for quick recovery
824 * on mount. This will return 0 if it was successfull in writing the cache out,
825 * and -1 if it was not.
826 */
827 int __btrfs_write_out_cache(struct btrfs_root *root, struct inode *inode,
828 struct btrfs_free_space_ctl *ctl,
829 struct btrfs_block_group_cache *block_group,
830 struct btrfs_trans_handle *trans,
831 struct btrfs_path *path, u64 offset)
832 {
833 struct btrfs_free_space_header *header;
834 struct extent_buffer *leaf;
835 struct rb_node *node;
836 struct list_head *pos, *n;
837 struct extent_state *cached_state = NULL;
838 struct btrfs_free_cluster *cluster = NULL;
839 struct extent_io_tree *unpin = NULL;
840 struct io_ctl io_ctl;
841 struct list_head bitmap_list;
842 struct btrfs_key key;
843 u64 start, extent_start, extent_end, len;
844 int entries = 0;
845 int bitmaps = 0;
846 int ret;
847 int err = -1;
848
849 INIT_LIST_HEAD(&bitmap_list);
850
851 if (!i_size_read(inode))
852 return -1;
853
854 io_ctl_init(&io_ctl, inode, root);
855
856 /* Get the cluster for this block_group if it exists */
857 if (block_group && !list_empty(&block_group->cluster_list))
858 cluster = list_entry(block_group->cluster_list.next,
859 struct btrfs_free_cluster,
860 block_group_list);
861
862 /* Lock all pages first so we can lock the extent safely. */
863 io_ctl_prepare_pages(&io_ctl, inode, 0);
864
865 lock_extent_bits(&BTRFS_I(inode)->io_tree, 0, i_size_read(inode) - 1,
866 0, &cached_state, GFP_NOFS);
867
868 node = rb_first(&ctl->free_space_offset);
869 if (!node && cluster) {
870 node = rb_first(&cluster->root);
871 cluster = NULL;
872 }
873
874 /* Make sure we can fit our crcs into the first page */
875 if (io_ctl.check_crcs &&
876 (io_ctl.num_pages * sizeof(u32)) >= PAGE_CACHE_SIZE) {
877 WARN_ON(1);
878 goto out_nospc;
879 }
880
881 io_ctl_set_generation(&io_ctl, trans->transid);
882
883 /* Write out the extent entries */
884 while (node) {
885 struct btrfs_free_space *e;
886
887 e = rb_entry(node, struct btrfs_free_space, offset_index);
888 entries++;
889
890 ret = io_ctl_add_entry(&io_ctl, e->offset, e->bytes,
891 e->bitmap);
892 if (ret)
893 goto out_nospc;
894
895 if (e->bitmap) {
896 list_add_tail(&e->list, &bitmap_list);
897 bitmaps++;
898 }
899 node = rb_next(node);
900 if (!node && cluster) {
901 node = rb_first(&cluster->root);
902 cluster = NULL;
903 }
904 }
905
906 /*
907 * We want to add any pinned extents to our free space cache
908 * so we don't leak the space
909 */
910
911 /*
912 * We shouldn't have switched the pinned extents yet so this is the
913 * right one
914 */
915 unpin = root->fs_info->pinned_extents;
916
917 if (block_group)
918 start = block_group->key.objectid;
919
920 while (block_group && (start < block_group->key.objectid +
921 block_group->key.offset)) {
922 ret = find_first_extent_bit(unpin, start,
923 &extent_start, &extent_end,
924 EXTENT_DIRTY);
925 if (ret) {
926 ret = 0;
927 break;
928 }
929
930 /* This pinned extent is out of our range */
931 if (extent_start >= block_group->key.objectid +
932 block_group->key.offset)
933 break;
934
935 extent_start = max(extent_start, start);
936 extent_end = min(block_group->key.objectid +
937 block_group->key.offset, extent_end + 1);
938 len = extent_end - extent_start;
939
940 entries++;
941 ret = io_ctl_add_entry(&io_ctl, extent_start, len, NULL);
942 if (ret)
943 goto out_nospc;
944
945 start = extent_end;
946 }
947
948 /* Write out the bitmaps */
949 list_for_each_safe(pos, n, &bitmap_list) {
950 struct btrfs_free_space *entry =
951 list_entry(pos, struct btrfs_free_space, list);
952
953 ret = io_ctl_add_bitmap(&io_ctl, entry->bitmap);
954 if (ret)
955 goto out_nospc;
956 list_del_init(&entry->list);
957 }
958
959 /* Zero out the rest of the pages just to make sure */
960 io_ctl_zero_remaining_pages(&io_ctl);
961
962 ret = btrfs_dirty_pages(root, inode, io_ctl.pages, io_ctl.num_pages,
963 0, i_size_read(inode), &cached_state);
964 io_ctl_drop_pages(&io_ctl);
965 unlock_extent_cached(&BTRFS_I(inode)->io_tree, 0,
966 i_size_read(inode) - 1, &cached_state, GFP_NOFS);
967
968 if (ret)
969 goto out;
970
971
972 ret = filemap_write_and_wait(inode->i_mapping);
973 if (ret)
974 goto out;
975
976 key.objectid = BTRFS_FREE_SPACE_OBJECTID;
977 key.offset = offset;
978 key.type = 0;
979
980 ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
981 if (ret < 0) {
982 clear_extent_bit(&BTRFS_I(inode)->io_tree, 0, inode->i_size - 1,
983 EXTENT_DIRTY | EXTENT_DELALLOC, 0, 0, NULL,
984 GFP_NOFS);
985 goto out;
986 }
987 leaf = path->nodes[0];
988 if (ret > 0) {
989 struct btrfs_key found_key;
990 BUG_ON(!path->slots[0]);
991 path->slots[0]--;
992 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
993 if (found_key.objectid != BTRFS_FREE_SPACE_OBJECTID ||
994 found_key.offset != offset) {
995 clear_extent_bit(&BTRFS_I(inode)->io_tree, 0,
996 inode->i_size - 1,
997 EXTENT_DIRTY | EXTENT_DELALLOC, 0, 0,
998 NULL, GFP_NOFS);
999 btrfs_release_path(path);
1000 goto out;
1001 }
1002 }
1003
1004 BTRFS_I(inode)->generation = trans->transid;
1005 header = btrfs_item_ptr(leaf, path->slots[0],
1006 struct btrfs_free_space_header);
1007 btrfs_set_free_space_entries(leaf, header, entries);
1008 btrfs_set_free_space_bitmaps(leaf, header, bitmaps);
1009 btrfs_set_free_space_generation(leaf, header, trans->transid);
1010 btrfs_mark_buffer_dirty(leaf);
1011 btrfs_release_path(path);
1012
1013 err = 0;
1014 out:
1015 io_ctl_free(&io_ctl);
1016 if (err) {
1017 invalidate_inode_pages2(inode->i_mapping);
1018 BTRFS_I(inode)->generation = 0;
1019 }
1020 btrfs_update_inode(trans, root, inode);
1021 return err;
1022
1023 out_nospc:
1024 list_for_each_safe(pos, n, &bitmap_list) {
1025 struct btrfs_free_space *entry =
1026 list_entry(pos, struct btrfs_free_space, list);
1027 list_del_init(&entry->list);
1028 }
1029 io_ctl_drop_pages(&io_ctl);
1030 unlock_extent_cached(&BTRFS_I(inode)->io_tree, 0,
1031 i_size_read(inode) - 1, &cached_state, GFP_NOFS);
1032 goto out;
1033 }
1034
1035 int btrfs_write_out_cache(struct btrfs_root *root,
1036 struct btrfs_trans_handle *trans,
1037 struct btrfs_block_group_cache *block_group,
1038 struct btrfs_path *path)
1039 {
1040 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
1041 struct inode *inode;
1042 int ret = 0;
1043
1044 root = root->fs_info->tree_root;
1045
1046 spin_lock(&block_group->lock);
1047 if (block_group->disk_cache_state < BTRFS_DC_SETUP) {
1048 spin_unlock(&block_group->lock);
1049 return 0;
1050 }
1051 spin_unlock(&block_group->lock);
1052
1053 inode = lookup_free_space_inode(root, block_group, path);
1054 if (IS_ERR(inode))
1055 return 0;
1056
1057 ret = __btrfs_write_out_cache(root, inode, ctl, block_group, trans,
1058 path, block_group->key.objectid);
1059 if (ret) {
1060 spin_lock(&block_group->lock);
1061 block_group->disk_cache_state = BTRFS_DC_ERROR;
1062 spin_unlock(&block_group->lock);
1063 ret = 0;
1064 #ifdef DEBUG
1065 printk(KERN_ERR "btrfs: failed to write free space cace "
1066 "for block group %llu\n", block_group->key.objectid);
1067 #endif
1068 }
1069
1070 iput(inode);
1071 return ret;
1072 }
1073
1074 static inline unsigned long offset_to_bit(u64 bitmap_start, u32 unit,
1075 u64 offset)
1076 {
1077 BUG_ON(offset < bitmap_start);
1078 offset -= bitmap_start;
1079 return (unsigned long)(div_u64(offset, unit));
1080 }
1081
1082 static inline unsigned long bytes_to_bits(u64 bytes, u32 unit)
1083 {
1084 return (unsigned long)(div_u64(bytes, unit));
1085 }
1086
1087 static inline u64 offset_to_bitmap(struct btrfs_free_space_ctl *ctl,
1088 u64 offset)
1089 {
1090 u64 bitmap_start;
1091 u64 bytes_per_bitmap;
1092
1093 bytes_per_bitmap = BITS_PER_BITMAP * ctl->unit;
1094 bitmap_start = offset - ctl->start;
1095 bitmap_start = div64_u64(bitmap_start, bytes_per_bitmap);
1096 bitmap_start *= bytes_per_bitmap;
1097 bitmap_start += ctl->start;
1098
1099 return bitmap_start;
1100 }
1101
1102 static int tree_insert_offset(struct rb_root *root, u64 offset,
1103 struct rb_node *node, int bitmap)
1104 {
1105 struct rb_node **p = &root->rb_node;
1106 struct rb_node *parent = NULL;
1107 struct btrfs_free_space *info;
1108
1109 while (*p) {
1110 parent = *p;
1111 info = rb_entry(parent, struct btrfs_free_space, offset_index);
1112
1113 if (offset < info->offset) {
1114 p = &(*p)->rb_left;
1115 } else if (offset > info->offset) {
1116 p = &(*p)->rb_right;
1117 } else {
1118 /*
1119 * we could have a bitmap entry and an extent entry
1120 * share the same offset. If this is the case, we want
1121 * the extent entry to always be found first if we do a
1122 * linear search through the tree, since we want to have
1123 * the quickest allocation time, and allocating from an
1124 * extent is faster than allocating from a bitmap. So
1125 * if we're inserting a bitmap and we find an entry at
1126 * this offset, we want to go right, or after this entry
1127 * logically. If we are inserting an extent and we've
1128 * found a bitmap, we want to go left, or before
1129 * logically.
1130 */
1131 if (bitmap) {
1132 if (info->bitmap) {
1133 WARN_ON_ONCE(1);
1134 return -EEXIST;
1135 }
1136 p = &(*p)->rb_right;
1137 } else {
1138 if (!info->bitmap) {
1139 WARN_ON_ONCE(1);
1140 return -EEXIST;
1141 }
1142 p = &(*p)->rb_left;
1143 }
1144 }
1145 }
1146
1147 rb_link_node(node, parent, p);
1148 rb_insert_color(node, root);
1149
1150 return 0;
1151 }
1152
1153 /*
1154 * searches the tree for the given offset.
1155 *
1156 * fuzzy - If this is set, then we are trying to make an allocation, and we just
1157 * want a section that has at least bytes size and comes at or after the given
1158 * offset.
1159 */
1160 static struct btrfs_free_space *
1161 tree_search_offset(struct btrfs_free_space_ctl *ctl,
1162 u64 offset, int bitmap_only, int fuzzy)
1163 {
1164 struct rb_node *n = ctl->free_space_offset.rb_node;
1165 struct btrfs_free_space *entry, *prev = NULL;
1166
1167 /* find entry that is closest to the 'offset' */
1168 while (1) {
1169 if (!n) {
1170 entry = NULL;
1171 break;
1172 }
1173
1174 entry = rb_entry(n, struct btrfs_free_space, offset_index);
1175 prev = entry;
1176
1177 if (offset < entry->offset)
1178 n = n->rb_left;
1179 else if (offset > entry->offset)
1180 n = n->rb_right;
1181 else
1182 break;
1183 }
1184
1185 if (bitmap_only) {
1186 if (!entry)
1187 return NULL;
1188 if (entry->bitmap)
1189 return entry;
1190
1191 /*
1192 * bitmap entry and extent entry may share same offset,
1193 * in that case, bitmap entry comes after extent entry.
1194 */
1195 n = rb_next(n);
1196 if (!n)
1197 return NULL;
1198 entry = rb_entry(n, struct btrfs_free_space, offset_index);
1199 if (entry->offset != offset)
1200 return NULL;
1201
1202 WARN_ON(!entry->bitmap);
1203 return entry;
1204 } else if (entry) {
1205 if (entry->bitmap) {
1206 /*
1207 * if previous extent entry covers the offset,
1208 * we should return it instead of the bitmap entry
1209 */
1210 n = &entry->offset_index;
1211 while (1) {
1212 n = rb_prev(n);
1213 if (!n)
1214 break;
1215 prev = rb_entry(n, struct btrfs_free_space,
1216 offset_index);
1217 if (!prev->bitmap) {
1218 if (prev->offset + prev->bytes > offset)
1219 entry = prev;
1220 break;
1221 }
1222 }
1223 }
1224 return entry;
1225 }
1226
1227 if (!prev)
1228 return NULL;
1229
1230 /* find last entry before the 'offset' */
1231 entry = prev;
1232 if (entry->offset > offset) {
1233 n = rb_prev(&entry->offset_index);
1234 if (n) {
1235 entry = rb_entry(n, struct btrfs_free_space,
1236 offset_index);
1237 BUG_ON(entry->offset > offset);
1238 } else {
1239 if (fuzzy)
1240 return entry;
1241 else
1242 return NULL;
1243 }
1244 }
1245
1246 if (entry->bitmap) {
1247 n = &entry->offset_index;
1248 while (1) {
1249 n = rb_prev(n);
1250 if (!n)
1251 break;
1252 prev = rb_entry(n, struct btrfs_free_space,
1253 offset_index);
1254 if (!prev->bitmap) {
1255 if (prev->offset + prev->bytes > offset)
1256 return prev;
1257 break;
1258 }
1259 }
1260 if (entry->offset + BITS_PER_BITMAP * ctl->unit > offset)
1261 return entry;
1262 } else if (entry->offset + entry->bytes > offset)
1263 return entry;
1264
1265 if (!fuzzy)
1266 return NULL;
1267
1268 while (1) {
1269 if (entry->bitmap) {
1270 if (entry->offset + BITS_PER_BITMAP *
1271 ctl->unit > offset)
1272 break;
1273 } else {
1274 if (entry->offset + entry->bytes > offset)
1275 break;
1276 }
1277
1278 n = rb_next(&entry->offset_index);
1279 if (!n)
1280 return NULL;
1281 entry = rb_entry(n, struct btrfs_free_space, offset_index);
1282 }
1283 return entry;
1284 }
1285
1286 static inline void
1287 __unlink_free_space(struct btrfs_free_space_ctl *ctl,
1288 struct btrfs_free_space *info)
1289 {
1290 rb_erase(&info->offset_index, &ctl->free_space_offset);
1291 ctl->free_extents--;
1292 }
1293
1294 static void unlink_free_space(struct btrfs_free_space_ctl *ctl,
1295 struct btrfs_free_space *info)
1296 {
1297 __unlink_free_space(ctl, info);
1298 ctl->free_space -= info->bytes;
1299 }
1300
1301 static int link_free_space(struct btrfs_free_space_ctl *ctl,
1302 struct btrfs_free_space *info)
1303 {
1304 int ret = 0;
1305
1306 BUG_ON(!info->bitmap && !info->bytes);
1307 ret = tree_insert_offset(&ctl->free_space_offset, info->offset,
1308 &info->offset_index, (info->bitmap != NULL));
1309 if (ret)
1310 return ret;
1311
1312 ctl->free_space += info->bytes;
1313 ctl->free_extents++;
1314 return ret;
1315 }
1316
1317 static void recalculate_thresholds(struct btrfs_free_space_ctl *ctl)
1318 {
1319 struct btrfs_block_group_cache *block_group = ctl->private;
1320 u64 max_bytes;
1321 u64 bitmap_bytes;
1322 u64 extent_bytes;
1323 u64 size = block_group->key.offset;
1324 u64 bytes_per_bg = BITS_PER_BITMAP * block_group->sectorsize;
1325 int max_bitmaps = div64_u64(size + bytes_per_bg - 1, bytes_per_bg);
1326
1327 BUG_ON(ctl->total_bitmaps > max_bitmaps);
1328
1329 /*
1330 * The goal is to keep the total amount of memory used per 1gb of space
1331 * at or below 32k, so we need to adjust how much memory we allow to be
1332 * used by extent based free space tracking
1333 */
1334 if (size < 1024 * 1024 * 1024)
1335 max_bytes = MAX_CACHE_BYTES_PER_GIG;
1336 else
1337 max_bytes = MAX_CACHE_BYTES_PER_GIG *
1338 div64_u64(size, 1024 * 1024 * 1024);
1339
1340 /*
1341 * we want to account for 1 more bitmap than what we have so we can make
1342 * sure we don't go over our overall goal of MAX_CACHE_BYTES_PER_GIG as
1343 * we add more bitmaps.
1344 */
1345 bitmap_bytes = (ctl->total_bitmaps + 1) * PAGE_CACHE_SIZE;
1346
1347 if (bitmap_bytes >= max_bytes) {
1348 ctl->extents_thresh = 0;
1349 return;
1350 }
1351
1352 /*
1353 * we want the extent entry threshold to always be at most 1/2 the maxw
1354 * bytes we can have, or whatever is less than that.
1355 */
1356 extent_bytes = max_bytes - bitmap_bytes;
1357 extent_bytes = min_t(u64, extent_bytes, div64_u64(max_bytes, 2));
1358
1359 ctl->extents_thresh =
1360 div64_u64(extent_bytes, (sizeof(struct btrfs_free_space)));
1361 }
1362
1363 static inline void __bitmap_clear_bits(struct btrfs_free_space_ctl *ctl,
1364 struct btrfs_free_space *info,
1365 u64 offset, u64 bytes)
1366 {
1367 unsigned long start, count;
1368
1369 start = offset_to_bit(info->offset, ctl->unit, offset);
1370 count = bytes_to_bits(bytes, ctl->unit);
1371 BUG_ON(start + count > BITS_PER_BITMAP);
1372
1373 bitmap_clear(info->bitmap, start, count);
1374
1375 info->bytes -= bytes;
1376 }
1377
1378 static void bitmap_clear_bits(struct btrfs_free_space_ctl *ctl,
1379 struct btrfs_free_space *info, u64 offset,
1380 u64 bytes)
1381 {
1382 __bitmap_clear_bits(ctl, info, offset, bytes);
1383 ctl->free_space -= bytes;
1384 }
1385
1386 static void bitmap_set_bits(struct btrfs_free_space_ctl *ctl,
1387 struct btrfs_free_space *info, u64 offset,
1388 u64 bytes)
1389 {
1390 unsigned long start, count;
1391
1392 start = offset_to_bit(info->offset, ctl->unit, offset);
1393 count = bytes_to_bits(bytes, ctl->unit);
1394 BUG_ON(start + count > BITS_PER_BITMAP);
1395
1396 bitmap_set(info->bitmap, start, count);
1397
1398 info->bytes += bytes;
1399 ctl->free_space += bytes;
1400 }
1401
1402 static int search_bitmap(struct btrfs_free_space_ctl *ctl,
1403 struct btrfs_free_space *bitmap_info, u64 *offset,
1404 u64 *bytes)
1405 {
1406 unsigned long found_bits = 0;
1407 unsigned long bits, i;
1408 unsigned long next_zero;
1409
1410 i = offset_to_bit(bitmap_info->offset, ctl->unit,
1411 max_t(u64, *offset, bitmap_info->offset));
1412 bits = bytes_to_bits(*bytes, ctl->unit);
1413
1414 for (i = find_next_bit(bitmap_info->bitmap, BITS_PER_BITMAP, i);
1415 i < BITS_PER_BITMAP;
1416 i = find_next_bit(bitmap_info->bitmap, BITS_PER_BITMAP, i + 1)) {
1417 next_zero = find_next_zero_bit(bitmap_info->bitmap,
1418 BITS_PER_BITMAP, i);
1419 if ((next_zero - i) >= bits) {
1420 found_bits = next_zero - i;
1421 break;
1422 }
1423 i = next_zero;
1424 }
1425
1426 if (found_bits) {
1427 *offset = (u64)(i * ctl->unit) + bitmap_info->offset;
1428 *bytes = (u64)(found_bits) * ctl->unit;
1429 return 0;
1430 }
1431
1432 return -1;
1433 }
1434
1435 static struct btrfs_free_space *
1436 find_free_space(struct btrfs_free_space_ctl *ctl, u64 *offset, u64 *bytes)
1437 {
1438 struct btrfs_free_space *entry;
1439 struct rb_node *node;
1440 int ret;
1441
1442 if (!ctl->free_space_offset.rb_node)
1443 return NULL;
1444
1445 entry = tree_search_offset(ctl, offset_to_bitmap(ctl, *offset), 0, 1);
1446 if (!entry)
1447 return NULL;
1448
1449 for (node = &entry->offset_index; node; node = rb_next(node)) {
1450 entry = rb_entry(node, struct btrfs_free_space, offset_index);
1451 if (entry->bytes < *bytes)
1452 continue;
1453
1454 if (entry->bitmap) {
1455 ret = search_bitmap(ctl, entry, offset, bytes);
1456 if (!ret)
1457 return entry;
1458 continue;
1459 }
1460
1461 *offset = entry->offset;
1462 *bytes = entry->bytes;
1463 return entry;
1464 }
1465
1466 return NULL;
1467 }
1468
1469 static void add_new_bitmap(struct btrfs_free_space_ctl *ctl,
1470 struct btrfs_free_space *info, u64 offset)
1471 {
1472 info->offset = offset_to_bitmap(ctl, offset);
1473 info->bytes = 0;
1474 INIT_LIST_HEAD(&info->list);
1475 link_free_space(ctl, info);
1476 ctl->total_bitmaps++;
1477
1478 ctl->op->recalc_thresholds(ctl);
1479 }
1480
1481 static void free_bitmap(struct btrfs_free_space_ctl *ctl,
1482 struct btrfs_free_space *bitmap_info)
1483 {
1484 unlink_free_space(ctl, bitmap_info);
1485 kfree(bitmap_info->bitmap);
1486 kmem_cache_free(btrfs_free_space_cachep, bitmap_info);
1487 ctl->total_bitmaps--;
1488 ctl->op->recalc_thresholds(ctl);
1489 }
1490
1491 static noinline int remove_from_bitmap(struct btrfs_free_space_ctl *ctl,
1492 struct btrfs_free_space *bitmap_info,
1493 u64 *offset, u64 *bytes)
1494 {
1495 u64 end;
1496 u64 search_start, search_bytes;
1497 int ret;
1498
1499 again:
1500 end = bitmap_info->offset + (u64)(BITS_PER_BITMAP * ctl->unit) - 1;
1501
1502 /*
1503 * XXX - this can go away after a few releases.
1504 *
1505 * since the only user of btrfs_remove_free_space is the tree logging
1506 * stuff, and the only way to test that is under crash conditions, we
1507 * want to have this debug stuff here just in case somethings not
1508 * working. Search the bitmap for the space we are trying to use to
1509 * make sure its actually there. If its not there then we need to stop
1510 * because something has gone wrong.
1511 */
1512 search_start = *offset;
1513 search_bytes = *bytes;
1514 search_bytes = min(search_bytes, end - search_start + 1);
1515 ret = search_bitmap(ctl, bitmap_info, &search_start, &search_bytes);
1516 BUG_ON(ret < 0 || search_start != *offset);
1517
1518 if (*offset > bitmap_info->offset && *offset + *bytes > end) {
1519 bitmap_clear_bits(ctl, bitmap_info, *offset, end - *offset + 1);
1520 *bytes -= end - *offset + 1;
1521 *offset = end + 1;
1522 } else if (*offset >= bitmap_info->offset && *offset + *bytes <= end) {
1523 bitmap_clear_bits(ctl, bitmap_info, *offset, *bytes);
1524 *bytes = 0;
1525 }
1526
1527 if (*bytes) {
1528 struct rb_node *next = rb_next(&bitmap_info->offset_index);
1529 if (!bitmap_info->bytes)
1530 free_bitmap(ctl, bitmap_info);
1531
1532 /*
1533 * no entry after this bitmap, but we still have bytes to
1534 * remove, so something has gone wrong.
1535 */
1536 if (!next)
1537 return -EINVAL;
1538
1539 bitmap_info = rb_entry(next, struct btrfs_free_space,
1540 offset_index);
1541
1542 /*
1543 * if the next entry isn't a bitmap we need to return to let the
1544 * extent stuff do its work.
1545 */
1546 if (!bitmap_info->bitmap)
1547 return -EAGAIN;
1548
1549 /*
1550 * Ok the next item is a bitmap, but it may not actually hold
1551 * the information for the rest of this free space stuff, so
1552 * look for it, and if we don't find it return so we can try
1553 * everything over again.
1554 */
1555 search_start = *offset;
1556 search_bytes = *bytes;
1557 ret = search_bitmap(ctl, bitmap_info, &search_start,
1558 &search_bytes);
1559 if (ret < 0 || search_start != *offset)
1560 return -EAGAIN;
1561
1562 goto again;
1563 } else if (!bitmap_info->bytes)
1564 free_bitmap(ctl, bitmap_info);
1565
1566 return 0;
1567 }
1568
1569 static u64 add_bytes_to_bitmap(struct btrfs_free_space_ctl *ctl,
1570 struct btrfs_free_space *info, u64 offset,
1571 u64 bytes)
1572 {
1573 u64 bytes_to_set = 0;
1574 u64 end;
1575
1576 end = info->offset + (u64)(BITS_PER_BITMAP * ctl->unit);
1577
1578 bytes_to_set = min(end - offset, bytes);
1579
1580 bitmap_set_bits(ctl, info, offset, bytes_to_set);
1581
1582 return bytes_to_set;
1583
1584 }
1585
1586 static bool use_bitmap(struct btrfs_free_space_ctl *ctl,
1587 struct btrfs_free_space *info)
1588 {
1589 struct btrfs_block_group_cache *block_group = ctl->private;
1590
1591 /*
1592 * If we are below the extents threshold then we can add this as an
1593 * extent, and don't have to deal with the bitmap
1594 */
1595 if (ctl->free_extents < ctl->extents_thresh) {
1596 /*
1597 * If this block group has some small extents we don't want to
1598 * use up all of our free slots in the cache with them, we want
1599 * to reserve them to larger extents, however if we have plent
1600 * of cache left then go ahead an dadd them, no sense in adding
1601 * the overhead of a bitmap if we don't have to.
1602 */
1603 if (info->bytes <= block_group->sectorsize * 4) {
1604 if (ctl->free_extents * 2 <= ctl->extents_thresh)
1605 return false;
1606 } else {
1607 return false;
1608 }
1609 }
1610
1611 /*
1612 * some block groups are so tiny they can't be enveloped by a bitmap, so
1613 * don't even bother to create a bitmap for this
1614 */
1615 if (BITS_PER_BITMAP * block_group->sectorsize >
1616 block_group->key.offset)
1617 return false;
1618
1619 return true;
1620 }
1621
1622 static struct btrfs_free_space_op free_space_op = {
1623 .recalc_thresholds = recalculate_thresholds,
1624 .use_bitmap = use_bitmap,
1625 };
1626
1627 static int insert_into_bitmap(struct btrfs_free_space_ctl *ctl,
1628 struct btrfs_free_space *info)
1629 {
1630 struct btrfs_free_space *bitmap_info;
1631 struct btrfs_block_group_cache *block_group = NULL;
1632 int added = 0;
1633 u64 bytes, offset, bytes_added;
1634 int ret;
1635
1636 bytes = info->bytes;
1637 offset = info->offset;
1638
1639 if (!ctl->op->use_bitmap(ctl, info))
1640 return 0;
1641
1642 if (ctl->op == &free_space_op)
1643 block_group = ctl->private;
1644 again:
1645 /*
1646 * Since we link bitmaps right into the cluster we need to see if we
1647 * have a cluster here, and if so and it has our bitmap we need to add
1648 * the free space to that bitmap.
1649 */
1650 if (block_group && !list_empty(&block_group->cluster_list)) {
1651 struct btrfs_free_cluster *cluster;
1652 struct rb_node *node;
1653 struct btrfs_free_space *entry;
1654
1655 cluster = list_entry(block_group->cluster_list.next,
1656 struct btrfs_free_cluster,
1657 block_group_list);
1658 spin_lock(&cluster->lock);
1659 node = rb_first(&cluster->root);
1660 if (!node) {
1661 spin_unlock(&cluster->lock);
1662 goto no_cluster_bitmap;
1663 }
1664
1665 entry = rb_entry(node, struct btrfs_free_space, offset_index);
1666 if (!entry->bitmap) {
1667 spin_unlock(&cluster->lock);
1668 goto no_cluster_bitmap;
1669 }
1670
1671 if (entry->offset == offset_to_bitmap(ctl, offset)) {
1672 bytes_added = add_bytes_to_bitmap(ctl, entry,
1673 offset, bytes);
1674 bytes -= bytes_added;
1675 offset += bytes_added;
1676 }
1677 spin_unlock(&cluster->lock);
1678 if (!bytes) {
1679 ret = 1;
1680 goto out;
1681 }
1682 }
1683
1684 no_cluster_bitmap:
1685 bitmap_info = tree_search_offset(ctl, offset_to_bitmap(ctl, offset),
1686 1, 0);
1687 if (!bitmap_info) {
1688 BUG_ON(added);
1689 goto new_bitmap;
1690 }
1691
1692 bytes_added = add_bytes_to_bitmap(ctl, bitmap_info, offset, bytes);
1693 bytes -= bytes_added;
1694 offset += bytes_added;
1695 added = 0;
1696
1697 if (!bytes) {
1698 ret = 1;
1699 goto out;
1700 } else
1701 goto again;
1702
1703 new_bitmap:
1704 if (info && info->bitmap) {
1705 add_new_bitmap(ctl, info, offset);
1706 added = 1;
1707 info = NULL;
1708 goto again;
1709 } else {
1710 spin_unlock(&ctl->tree_lock);
1711
1712 /* no pre-allocated info, allocate a new one */
1713 if (!info) {
1714 info = kmem_cache_zalloc(btrfs_free_space_cachep,
1715 GFP_NOFS);
1716 if (!info) {
1717 spin_lock(&ctl->tree_lock);
1718 ret = -ENOMEM;
1719 goto out;
1720 }
1721 }
1722
1723 /* allocate the bitmap */
1724 info->bitmap = kzalloc(PAGE_CACHE_SIZE, GFP_NOFS);
1725 spin_lock(&ctl->tree_lock);
1726 if (!info->bitmap) {
1727 ret = -ENOMEM;
1728 goto out;
1729 }
1730 goto again;
1731 }
1732
1733 out:
1734 if (info) {
1735 if (info->bitmap)
1736 kfree(info->bitmap);
1737 kmem_cache_free(btrfs_free_space_cachep, info);
1738 }
1739
1740 return ret;
1741 }
1742
1743 static bool try_merge_free_space(struct btrfs_free_space_ctl *ctl,
1744 struct btrfs_free_space *info, bool update_stat)
1745 {
1746 struct btrfs_free_space *left_info;
1747 struct btrfs_free_space *right_info;
1748 bool merged = false;
1749 u64 offset = info->offset;
1750 u64 bytes = info->bytes;
1751
1752 /*
1753 * first we want to see if there is free space adjacent to the range we
1754 * are adding, if there is remove that struct and add a new one to
1755 * cover the entire range
1756 */
1757 right_info = tree_search_offset(ctl, offset + bytes, 0, 0);
1758 if (right_info && rb_prev(&right_info->offset_index))
1759 left_info = rb_entry(rb_prev(&right_info->offset_index),
1760 struct btrfs_free_space, offset_index);
1761 else
1762 left_info = tree_search_offset(ctl, offset - 1, 0, 0);
1763
1764 if (right_info && !right_info->bitmap) {
1765 if (update_stat)
1766 unlink_free_space(ctl, right_info);
1767 else
1768 __unlink_free_space(ctl, right_info);
1769 info->bytes += right_info->bytes;
1770 kmem_cache_free(btrfs_free_space_cachep, right_info);
1771 merged = true;
1772 }
1773
1774 if (left_info && !left_info->bitmap &&
1775 left_info->offset + left_info->bytes == offset) {
1776 if (update_stat)
1777 unlink_free_space(ctl, left_info);
1778 else
1779 __unlink_free_space(ctl, left_info);
1780 info->offset = left_info->offset;
1781 info->bytes += left_info->bytes;
1782 kmem_cache_free(btrfs_free_space_cachep, left_info);
1783 merged = true;
1784 }
1785
1786 return merged;
1787 }
1788
1789 int __btrfs_add_free_space(struct btrfs_free_space_ctl *ctl,
1790 u64 offset, u64 bytes)
1791 {
1792 struct btrfs_free_space *info;
1793 int ret = 0;
1794
1795 info = kmem_cache_zalloc(btrfs_free_space_cachep, GFP_NOFS);
1796 if (!info)
1797 return -ENOMEM;
1798
1799 info->offset = offset;
1800 info->bytes = bytes;
1801
1802 spin_lock(&ctl->tree_lock);
1803
1804 if (try_merge_free_space(ctl, info, true))
1805 goto link;
1806
1807 /*
1808 * There was no extent directly to the left or right of this new
1809 * extent then we know we're going to have to allocate a new extent, so
1810 * before we do that see if we need to drop this into a bitmap
1811 */
1812 ret = insert_into_bitmap(ctl, info);
1813 if (ret < 0) {
1814 goto out;
1815 } else if (ret) {
1816 ret = 0;
1817 goto out;
1818 }
1819 link:
1820 ret = link_free_space(ctl, info);
1821 if (ret)
1822 kmem_cache_free(btrfs_free_space_cachep, info);
1823 out:
1824 spin_unlock(&ctl->tree_lock);
1825
1826 if (ret) {
1827 printk(KERN_CRIT "btrfs: unable to add free space :%d\n", ret);
1828 BUG_ON(ret == -EEXIST);
1829 }
1830
1831 return ret;
1832 }
1833
1834 int btrfs_remove_free_space(struct btrfs_block_group_cache *block_group,
1835 u64 offset, u64 bytes)
1836 {
1837 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
1838 struct btrfs_free_space *info;
1839 struct btrfs_free_space *next_info = NULL;
1840 int ret = 0;
1841
1842 spin_lock(&ctl->tree_lock);
1843
1844 again:
1845 info = tree_search_offset(ctl, offset, 0, 0);
1846 if (!info) {
1847 /*
1848 * oops didn't find an extent that matched the space we wanted
1849 * to remove, look for a bitmap instead
1850 */
1851 info = tree_search_offset(ctl, offset_to_bitmap(ctl, offset),
1852 1, 0);
1853 if (!info) {
1854 /* the tree logging code might be calling us before we
1855 * have fully loaded the free space rbtree for this
1856 * block group. So it is possible the entry won't
1857 * be in the rbtree yet at all. The caching code
1858 * will make sure not to put it in the rbtree if
1859 * the logging code has pinned it.
1860 */
1861 goto out_lock;
1862 }
1863 }
1864
1865 if (info->bytes < bytes && rb_next(&info->offset_index)) {
1866 u64 end;
1867 next_info = rb_entry(rb_next(&info->offset_index),
1868 struct btrfs_free_space,
1869 offset_index);
1870
1871 if (next_info->bitmap)
1872 end = next_info->offset +
1873 BITS_PER_BITMAP * ctl->unit - 1;
1874 else
1875 end = next_info->offset + next_info->bytes;
1876
1877 if (next_info->bytes < bytes ||
1878 next_info->offset > offset || offset > end) {
1879 printk(KERN_CRIT "Found free space at %llu, size %llu,"
1880 " trying to use %llu\n",
1881 (unsigned long long)info->offset,
1882 (unsigned long long)info->bytes,
1883 (unsigned long long)bytes);
1884 WARN_ON(1);
1885 ret = -EINVAL;
1886 goto out_lock;
1887 }
1888
1889 info = next_info;
1890 }
1891
1892 if (info->bytes == bytes) {
1893 unlink_free_space(ctl, info);
1894 if (info->bitmap) {
1895 kfree(info->bitmap);
1896 ctl->total_bitmaps--;
1897 }
1898 kmem_cache_free(btrfs_free_space_cachep, info);
1899 ret = 0;
1900 goto out_lock;
1901 }
1902
1903 if (!info->bitmap && info->offset == offset) {
1904 unlink_free_space(ctl, info);
1905 info->offset += bytes;
1906 info->bytes -= bytes;
1907 ret = link_free_space(ctl, info);
1908 WARN_ON(ret);
1909 goto out_lock;
1910 }
1911
1912 if (!info->bitmap && info->offset <= offset &&
1913 info->offset + info->bytes >= offset + bytes) {
1914 u64 old_start = info->offset;
1915 /*
1916 * we're freeing space in the middle of the info,
1917 * this can happen during tree log replay
1918 *
1919 * first unlink the old info and then
1920 * insert it again after the hole we're creating
1921 */
1922 unlink_free_space(ctl, info);
1923 if (offset + bytes < info->offset + info->bytes) {
1924 u64 old_end = info->offset + info->bytes;
1925
1926 info->offset = offset + bytes;
1927 info->bytes = old_end - info->offset;
1928 ret = link_free_space(ctl, info);
1929 WARN_ON(ret);
1930 if (ret)
1931 goto out_lock;
1932 } else {
1933 /* the hole we're creating ends at the end
1934 * of the info struct, just free the info
1935 */
1936 kmem_cache_free(btrfs_free_space_cachep, info);
1937 }
1938 spin_unlock(&ctl->tree_lock);
1939
1940 /* step two, insert a new info struct to cover
1941 * anything before the hole
1942 */
1943 ret = btrfs_add_free_space(block_group, old_start,
1944 offset - old_start);
1945 WARN_ON(ret);
1946 goto out;
1947 }
1948
1949 ret = remove_from_bitmap(ctl, info, &offset, &bytes);
1950 if (ret == -EAGAIN)
1951 goto again;
1952 BUG_ON(ret);
1953 out_lock:
1954 spin_unlock(&ctl->tree_lock);
1955 out:
1956 return ret;
1957 }
1958
1959 void btrfs_dump_free_space(struct btrfs_block_group_cache *block_group,
1960 u64 bytes)
1961 {
1962 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
1963 struct btrfs_free_space *info;
1964 struct rb_node *n;
1965 int count = 0;
1966
1967 for (n = rb_first(&ctl->free_space_offset); n; n = rb_next(n)) {
1968 info = rb_entry(n, struct btrfs_free_space, offset_index);
1969 if (info->bytes >= bytes)
1970 count++;
1971 printk(KERN_CRIT "entry offset %llu, bytes %llu, bitmap %s\n",
1972 (unsigned long long)info->offset,
1973 (unsigned long long)info->bytes,
1974 (info->bitmap) ? "yes" : "no");
1975 }
1976 printk(KERN_INFO "block group has cluster?: %s\n",
1977 list_empty(&block_group->cluster_list) ? "no" : "yes");
1978 printk(KERN_INFO "%d blocks of free space at or bigger than bytes is"
1979 "\n", count);
1980 }
1981
1982 void btrfs_init_free_space_ctl(struct btrfs_block_group_cache *block_group)
1983 {
1984 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
1985
1986 spin_lock_init(&ctl->tree_lock);
1987 ctl->unit = block_group->sectorsize;
1988 ctl->start = block_group->key.objectid;
1989 ctl->private = block_group;
1990 ctl->op = &free_space_op;
1991
1992 /*
1993 * we only want to have 32k of ram per block group for keeping
1994 * track of free space, and if we pass 1/2 of that we want to
1995 * start converting things over to using bitmaps
1996 */
1997 ctl->extents_thresh = ((1024 * 32) / 2) /
1998 sizeof(struct btrfs_free_space);
1999 }
2000
2001 /*
2002 * for a given cluster, put all of its extents back into the free
2003 * space cache. If the block group passed doesn't match the block group
2004 * pointed to by the cluster, someone else raced in and freed the
2005 * cluster already. In that case, we just return without changing anything
2006 */
2007 static int
2008 __btrfs_return_cluster_to_free_space(
2009 struct btrfs_block_group_cache *block_group,
2010 struct btrfs_free_cluster *cluster)
2011 {
2012 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2013 struct btrfs_free_space *entry;
2014 struct rb_node *node;
2015
2016 spin_lock(&cluster->lock);
2017 if (cluster->block_group != block_group)
2018 goto out;
2019
2020 cluster->block_group = NULL;
2021 cluster->window_start = 0;
2022 list_del_init(&cluster->block_group_list);
2023
2024 node = rb_first(&cluster->root);
2025 while (node) {
2026 bool bitmap;
2027
2028 entry = rb_entry(node, struct btrfs_free_space, offset_index);
2029 node = rb_next(&entry->offset_index);
2030 rb_erase(&entry->offset_index, &cluster->root);
2031
2032 bitmap = (entry->bitmap != NULL);
2033 if (!bitmap)
2034 try_merge_free_space(ctl, entry, false);
2035 tree_insert_offset(&ctl->free_space_offset,
2036 entry->offset, &entry->offset_index, bitmap);
2037 }
2038 cluster->root = RB_ROOT;
2039
2040 out:
2041 spin_unlock(&cluster->lock);
2042 btrfs_put_block_group(block_group);
2043 return 0;
2044 }
2045
2046 void __btrfs_remove_free_space_cache_locked(struct btrfs_free_space_ctl *ctl)
2047 {
2048 struct btrfs_free_space *info;
2049 struct rb_node *node;
2050
2051 while ((node = rb_last(&ctl->free_space_offset)) != NULL) {
2052 info = rb_entry(node, struct btrfs_free_space, offset_index);
2053 if (!info->bitmap) {
2054 unlink_free_space(ctl, info);
2055 kmem_cache_free(btrfs_free_space_cachep, info);
2056 } else {
2057 free_bitmap(ctl, info);
2058 }
2059 if (need_resched()) {
2060 spin_unlock(&ctl->tree_lock);
2061 cond_resched();
2062 spin_lock(&ctl->tree_lock);
2063 }
2064 }
2065 }
2066
2067 void __btrfs_remove_free_space_cache(struct btrfs_free_space_ctl *ctl)
2068 {
2069 spin_lock(&ctl->tree_lock);
2070 __btrfs_remove_free_space_cache_locked(ctl);
2071 spin_unlock(&ctl->tree_lock);
2072 }
2073
2074 void btrfs_remove_free_space_cache(struct btrfs_block_group_cache *block_group)
2075 {
2076 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2077 struct btrfs_free_cluster *cluster;
2078 struct list_head *head;
2079
2080 spin_lock(&ctl->tree_lock);
2081 while ((head = block_group->cluster_list.next) !=
2082 &block_group->cluster_list) {
2083 cluster = list_entry(head, struct btrfs_free_cluster,
2084 block_group_list);
2085
2086 WARN_ON(cluster->block_group != block_group);
2087 __btrfs_return_cluster_to_free_space(block_group, cluster);
2088 if (need_resched()) {
2089 spin_unlock(&ctl->tree_lock);
2090 cond_resched();
2091 spin_lock(&ctl->tree_lock);
2092 }
2093 }
2094 __btrfs_remove_free_space_cache_locked(ctl);
2095 spin_unlock(&ctl->tree_lock);
2096
2097 }
2098
2099 u64 btrfs_find_space_for_alloc(struct btrfs_block_group_cache *block_group,
2100 u64 offset, u64 bytes, u64 empty_size)
2101 {
2102 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2103 struct btrfs_free_space *entry = NULL;
2104 u64 bytes_search = bytes + empty_size;
2105 u64 ret = 0;
2106
2107 spin_lock(&ctl->tree_lock);
2108 entry = find_free_space(ctl, &offset, &bytes_search);
2109 if (!entry)
2110 goto out;
2111
2112 ret = offset;
2113 if (entry->bitmap) {
2114 bitmap_clear_bits(ctl, entry, offset, bytes);
2115 if (!entry->bytes)
2116 free_bitmap(ctl, entry);
2117 } else {
2118 unlink_free_space(ctl, entry);
2119 entry->offset += bytes;
2120 entry->bytes -= bytes;
2121 if (!entry->bytes)
2122 kmem_cache_free(btrfs_free_space_cachep, entry);
2123 else
2124 link_free_space(ctl, entry);
2125 }
2126
2127 out:
2128 spin_unlock(&ctl->tree_lock);
2129
2130 return ret;
2131 }
2132
2133 /*
2134 * given a cluster, put all of its extents back into the free space
2135 * cache. If a block group is passed, this function will only free
2136 * a cluster that belongs to the passed block group.
2137 *
2138 * Otherwise, it'll get a reference on the block group pointed to by the
2139 * cluster and remove the cluster from it.
2140 */
2141 int btrfs_return_cluster_to_free_space(
2142 struct btrfs_block_group_cache *block_group,
2143 struct btrfs_free_cluster *cluster)
2144 {
2145 struct btrfs_free_space_ctl *ctl;
2146 int ret;
2147
2148 /* first, get a safe pointer to the block group */
2149 spin_lock(&cluster->lock);
2150 if (!block_group) {
2151 block_group = cluster->block_group;
2152 if (!block_group) {
2153 spin_unlock(&cluster->lock);
2154 return 0;
2155 }
2156 } else if (cluster->block_group != block_group) {
2157 /* someone else has already freed it don't redo their work */
2158 spin_unlock(&cluster->lock);
2159 return 0;
2160 }
2161 atomic_inc(&block_group->count);
2162 spin_unlock(&cluster->lock);
2163
2164 ctl = block_group->free_space_ctl;
2165
2166 /* now return any extents the cluster had on it */
2167 spin_lock(&ctl->tree_lock);
2168 ret = __btrfs_return_cluster_to_free_space(block_group, cluster);
2169 spin_unlock(&ctl->tree_lock);
2170
2171 /* finally drop our ref */
2172 btrfs_put_block_group(block_group);
2173 return ret;
2174 }
2175
2176 static u64 btrfs_alloc_from_bitmap(struct btrfs_block_group_cache *block_group,
2177 struct btrfs_free_cluster *cluster,
2178 struct btrfs_free_space *entry,
2179 u64 bytes, u64 min_start)
2180 {
2181 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2182 int err;
2183 u64 search_start = cluster->window_start;
2184 u64 search_bytes = bytes;
2185 u64 ret = 0;
2186
2187 search_start = min_start;
2188 search_bytes = bytes;
2189
2190 err = search_bitmap(ctl, entry, &search_start, &search_bytes);
2191 if (err)
2192 return 0;
2193
2194 ret = search_start;
2195 __bitmap_clear_bits(ctl, entry, ret, bytes);
2196
2197 return ret;
2198 }
2199
2200 /*
2201 * given a cluster, try to allocate 'bytes' from it, returns 0
2202 * if it couldn't find anything suitably large, or a logical disk offset
2203 * if things worked out
2204 */
2205 u64 btrfs_alloc_from_cluster(struct btrfs_block_group_cache *block_group,
2206 struct btrfs_free_cluster *cluster, u64 bytes,
2207 u64 min_start)
2208 {
2209 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2210 struct btrfs_free_space *entry = NULL;
2211 struct rb_node *node;
2212 u64 ret = 0;
2213
2214 spin_lock(&cluster->lock);
2215 if (bytes > cluster->max_size)
2216 goto out;
2217
2218 if (cluster->block_group != block_group)
2219 goto out;
2220
2221 node = rb_first(&cluster->root);
2222 if (!node)
2223 goto out;
2224
2225 entry = rb_entry(node, struct btrfs_free_space, offset_index);
2226 while(1) {
2227 if (entry->bytes < bytes ||
2228 (!entry->bitmap && entry->offset < min_start)) {
2229 node = rb_next(&entry->offset_index);
2230 if (!node)
2231 break;
2232 entry = rb_entry(node, struct btrfs_free_space,
2233 offset_index);
2234 continue;
2235 }
2236
2237 if (entry->bitmap) {
2238 ret = btrfs_alloc_from_bitmap(block_group,
2239 cluster, entry, bytes,
2240 min_start);
2241 if (ret == 0) {
2242 node = rb_next(&entry->offset_index);
2243 if (!node)
2244 break;
2245 entry = rb_entry(node, struct btrfs_free_space,
2246 offset_index);
2247 continue;
2248 }
2249 } else {
2250 ret = entry->offset;
2251
2252 entry->offset += bytes;
2253 entry->bytes -= bytes;
2254 }
2255
2256 if (entry->bytes == 0)
2257 rb_erase(&entry->offset_index, &cluster->root);
2258 break;
2259 }
2260 out:
2261 spin_unlock(&cluster->lock);
2262
2263 if (!ret)
2264 return 0;
2265
2266 spin_lock(&ctl->tree_lock);
2267
2268 ctl->free_space -= bytes;
2269 if (entry->bytes == 0) {
2270 ctl->free_extents--;
2271 if (entry->bitmap) {
2272 kfree(entry->bitmap);
2273 ctl->total_bitmaps--;
2274 ctl->op->recalc_thresholds(ctl);
2275 }
2276 kmem_cache_free(btrfs_free_space_cachep, entry);
2277 }
2278
2279 spin_unlock(&ctl->tree_lock);
2280
2281 return ret;
2282 }
2283
2284 static int btrfs_bitmap_cluster(struct btrfs_block_group_cache *block_group,
2285 struct btrfs_free_space *entry,
2286 struct btrfs_free_cluster *cluster,
2287 u64 offset, u64 bytes, u64 min_bytes)
2288 {
2289 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2290 unsigned long next_zero;
2291 unsigned long i;
2292 unsigned long search_bits;
2293 unsigned long total_bits;
2294 unsigned long found_bits;
2295 unsigned long start = 0;
2296 unsigned long total_found = 0;
2297 int ret;
2298 bool found = false;
2299
2300 i = offset_to_bit(entry->offset, block_group->sectorsize,
2301 max_t(u64, offset, entry->offset));
2302 search_bits = bytes_to_bits(bytes, block_group->sectorsize);
2303 total_bits = bytes_to_bits(min_bytes, block_group->sectorsize);
2304
2305 again:
2306 found_bits = 0;
2307 for (i = find_next_bit(entry->bitmap, BITS_PER_BITMAP, i);
2308 i < BITS_PER_BITMAP;
2309 i = find_next_bit(entry->bitmap, BITS_PER_BITMAP, i + 1)) {
2310 next_zero = find_next_zero_bit(entry->bitmap,
2311 BITS_PER_BITMAP, i);
2312 if (next_zero - i >= search_bits) {
2313 found_bits = next_zero - i;
2314 break;
2315 }
2316 i = next_zero;
2317 }
2318
2319 if (!found_bits)
2320 return -ENOSPC;
2321
2322 if (!found) {
2323 start = i;
2324 cluster->max_size = 0;
2325 found = true;
2326 }
2327
2328 total_found += found_bits;
2329
2330 if (cluster->max_size < found_bits * block_group->sectorsize)
2331 cluster->max_size = found_bits * block_group->sectorsize;
2332
2333 if (total_found < total_bits) {
2334 i = find_next_bit(entry->bitmap, BITS_PER_BITMAP, next_zero);
2335 if (i - start > total_bits * 2) {
2336 total_found = 0;
2337 cluster->max_size = 0;
2338 found = false;
2339 }
2340 goto again;
2341 }
2342
2343 cluster->window_start = start * block_group->sectorsize +
2344 entry->offset;
2345 rb_erase(&entry->offset_index, &ctl->free_space_offset);
2346 ret = tree_insert_offset(&cluster->root, entry->offset,
2347 &entry->offset_index, 1);
2348 BUG_ON(ret);
2349
2350 return 0;
2351 }
2352
2353 /*
2354 * This searches the block group for just extents to fill the cluster with.
2355 */
2356 static noinline int
2357 setup_cluster_no_bitmap(struct btrfs_block_group_cache *block_group,
2358 struct btrfs_free_cluster *cluster,
2359 struct list_head *bitmaps, u64 offset, u64 bytes,
2360 u64 min_bytes)
2361 {
2362 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2363 struct btrfs_free_space *first = NULL;
2364 struct btrfs_free_space *entry = NULL;
2365 struct btrfs_free_space *prev = 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 max_gap = 128 * 1024;
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) {
2382 if (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 prev = entry;
2396
2397 while (window_free <= min_bytes) {
2398 node = rb_next(&entry->offset_index);
2399 if (!node)
2400 return -ENOSPC;
2401 entry = rb_entry(node, struct btrfs_free_space, offset_index);
2402
2403 if (entry->bitmap) {
2404 if (list_empty(&entry->list))
2405 list_add_tail(&entry->list, bitmaps);
2406 continue;
2407 }
2408
2409 /*
2410 * we haven't filled the empty size and the window is
2411 * very large. reset and try again
2412 */
2413 if (entry->offset - (prev->offset + prev->bytes) > max_gap ||
2414 entry->offset - window_start > (min_bytes * 2)) {
2415 first = entry;
2416 window_start = entry->offset;
2417 window_free = entry->bytes;
2418 last = entry;
2419 max_extent = entry->bytes;
2420 } else {
2421 last = entry;
2422 window_free += entry->bytes;
2423 if (entry->bytes > max_extent)
2424 max_extent = entry->bytes;
2425 }
2426 prev = entry;
2427 }
2428
2429 cluster->window_start = first->offset;
2430
2431 node = &first->offset_index;
2432
2433 /*
2434 * now we've found our entries, pull them out of the free space
2435 * cache and put them into the cluster rbtree
2436 */
2437 do {
2438 int ret;
2439
2440 entry = rb_entry(node, struct btrfs_free_space, offset_index);
2441 node = rb_next(&entry->offset_index);
2442 if (entry->bitmap)
2443 continue;
2444
2445 rb_erase(&entry->offset_index, &ctl->free_space_offset);
2446 ret = tree_insert_offset(&cluster->root, entry->offset,
2447 &entry->offset_index, 0);
2448 BUG_ON(ret);
2449 } while (node && entry != last);
2450
2451 cluster->max_size = max_extent;
2452
2453 return 0;
2454 }
2455
2456 /*
2457 * This specifically looks for bitmaps that may work in the cluster, we assume
2458 * that we have already failed to find extents that will work.
2459 */
2460 static noinline int
2461 setup_cluster_bitmap(struct btrfs_block_group_cache *block_group,
2462 struct btrfs_free_cluster *cluster,
2463 struct list_head *bitmaps, u64 offset, u64 bytes,
2464 u64 min_bytes)
2465 {
2466 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2467 struct btrfs_free_space *entry;
2468 int ret = -ENOSPC;
2469 u64 bitmap_offset = offset_to_bitmap(ctl, offset);
2470
2471 if (ctl->total_bitmaps == 0)
2472 return -ENOSPC;
2473
2474 /*
2475 * The bitmap that covers offset won't be in the list unless offset
2476 * is just its start offset.
2477 */
2478 entry = list_first_entry(bitmaps, struct btrfs_free_space, list);
2479 if (entry->offset != bitmap_offset) {
2480 entry = tree_search_offset(ctl, bitmap_offset, 1, 0);
2481 if (entry && list_empty(&entry->list))
2482 list_add(&entry->list, bitmaps);
2483 }
2484
2485 list_for_each_entry(entry, bitmaps, list) {
2486 if (entry->bytes < min_bytes)
2487 continue;
2488 ret = btrfs_bitmap_cluster(block_group, entry, cluster, offset,
2489 bytes, min_bytes);
2490 if (!ret)
2491 return 0;
2492 }
2493
2494 /*
2495 * The bitmaps list has all the bitmaps that record free space
2496 * starting after offset, so no more search is required.
2497 */
2498 return -ENOSPC;
2499 }
2500
2501 /*
2502 * here we try to find a cluster of blocks in a block group. The goal
2503 * is to find at least bytes free and up to empty_size + bytes free.
2504 * We might not find them all in one contiguous area.
2505 *
2506 * returns zero and sets up cluster if things worked out, otherwise
2507 * it returns -enospc
2508 */
2509 int btrfs_find_space_cluster(struct btrfs_trans_handle *trans,
2510 struct btrfs_root *root,
2511 struct btrfs_block_group_cache *block_group,
2512 struct btrfs_free_cluster *cluster,
2513 u64 offset, u64 bytes, u64 empty_size)
2514 {
2515 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2516 struct btrfs_free_space *entry, *tmp;
2517 LIST_HEAD(bitmaps);
2518 u64 min_bytes;
2519 int ret;
2520
2521 /* for metadata, allow allocates with more holes */
2522 if (btrfs_test_opt(root, SSD_SPREAD)) {
2523 min_bytes = bytes + empty_size;
2524 } else if (block_group->flags & BTRFS_BLOCK_GROUP_METADATA) {
2525 /*
2526 * we want to do larger allocations when we are
2527 * flushing out the delayed refs, it helps prevent
2528 * making more work as we go along.
2529 */
2530 if (trans->transaction->delayed_refs.flushing)
2531 min_bytes = max(bytes, (bytes + empty_size) >> 1);
2532 else
2533 min_bytes = max(bytes, (bytes + empty_size) >> 4);
2534 } else
2535 min_bytes = max(bytes, (bytes + empty_size) >> 2);
2536
2537 spin_lock(&ctl->tree_lock);
2538
2539 /*
2540 * If we know we don't have enough space to make a cluster don't even
2541 * bother doing all the work to try and find one.
2542 */
2543 if (ctl->free_space < min_bytes) {
2544 spin_unlock(&ctl->tree_lock);
2545 return -ENOSPC;
2546 }
2547
2548 spin_lock(&cluster->lock);
2549
2550 /* someone already found a cluster, hooray */
2551 if (cluster->block_group) {
2552 ret = 0;
2553 goto out;
2554 }
2555
2556 ret = setup_cluster_no_bitmap(block_group, cluster, &bitmaps, offset,
2557 bytes, min_bytes);
2558 if (ret)
2559 ret = setup_cluster_bitmap(block_group, cluster, &bitmaps,
2560 offset, bytes, min_bytes);
2561
2562 /* Clear our temporary list */
2563 list_for_each_entry_safe(entry, tmp, &bitmaps, list)
2564 list_del_init(&entry->list);
2565
2566 if (!ret) {
2567 atomic_inc(&block_group->count);
2568 list_add_tail(&cluster->block_group_list,
2569 &block_group->cluster_list);
2570 cluster->block_group = block_group;
2571 }
2572 out:
2573 spin_unlock(&cluster->lock);
2574 spin_unlock(&ctl->tree_lock);
2575
2576 return ret;
2577 }
2578
2579 /*
2580 * simple code to zero out a cluster
2581 */
2582 void btrfs_init_free_cluster(struct btrfs_free_cluster *cluster)
2583 {
2584 spin_lock_init(&cluster->lock);
2585 spin_lock_init(&cluster->refill_lock);
2586 cluster->root = RB_ROOT;
2587 cluster->max_size = 0;
2588 INIT_LIST_HEAD(&cluster->block_group_list);
2589 cluster->block_group = NULL;
2590 }
2591
2592 int btrfs_trim_block_group(struct btrfs_block_group_cache *block_group,
2593 u64 *trimmed, u64 start, u64 end, u64 minlen)
2594 {
2595 struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2596 struct btrfs_free_space *entry = NULL;
2597 struct btrfs_fs_info *fs_info = block_group->fs_info;
2598 u64 bytes = 0;
2599 u64 actually_trimmed;
2600 int ret = 0;
2601
2602 *trimmed = 0;
2603
2604 while (start < end) {
2605 spin_lock(&ctl->tree_lock);
2606
2607 if (ctl->free_space < minlen) {
2608 spin_unlock(&ctl->tree_lock);
2609 break;
2610 }
2611
2612 entry = tree_search_offset(ctl, start, 0, 1);
2613 if (!entry)
2614 entry = tree_search_offset(ctl,
2615 offset_to_bitmap(ctl, start),
2616 1, 1);
2617
2618 if (!entry || entry->offset >= end) {
2619 spin_unlock(&ctl->tree_lock);
2620 break;
2621 }
2622
2623 if (entry->bitmap) {
2624 ret = search_bitmap(ctl, entry, &start, &bytes);
2625 if (!ret) {
2626 if (start >= end) {
2627 spin_unlock(&ctl->tree_lock);
2628 break;
2629 }
2630 bytes = min(bytes, end - start);
2631 bitmap_clear_bits(ctl, entry, start, bytes);
2632 if (entry->bytes == 0)
2633 free_bitmap(ctl, entry);
2634 } else {
2635 start = entry->offset + BITS_PER_BITMAP *
2636 block_group->sectorsize;
2637 spin_unlock(&ctl->tree_lock);
2638 ret = 0;
2639 continue;
2640 }
2641 } else {
2642 start = entry->offset;
2643 bytes = min(entry->bytes, end - start);
2644 unlink_free_space(ctl, entry);
2645 kmem_cache_free(btrfs_free_space_cachep, entry);
2646 }
2647
2648 spin_unlock(&ctl->tree_lock);
2649
2650 if (bytes >= minlen) {
2651 struct btrfs_space_info *space_info;
2652 int update = 0;
2653
2654 space_info = block_group->space_info;
2655 spin_lock(&space_info->lock);
2656 spin_lock(&block_group->lock);
2657 if (!block_group->ro) {
2658 block_group->reserved += bytes;
2659 space_info->bytes_reserved += bytes;
2660 update = 1;
2661 }
2662 spin_unlock(&block_group->lock);
2663 spin_unlock(&space_info->lock);
2664
2665 ret = btrfs_error_discard_extent(fs_info->extent_root,
2666 start,
2667 bytes,
2668 &actually_trimmed);
2669
2670 btrfs_add_free_space(block_group, start, bytes);
2671 if (update) {
2672 spin_lock(&space_info->lock);
2673 spin_lock(&block_group->lock);
2674 if (block_group->ro)
2675 space_info->bytes_readonly += bytes;
2676 block_group->reserved -= bytes;
2677 space_info->bytes_reserved -= bytes;
2678 spin_unlock(&space_info->lock);
2679 spin_unlock(&block_group->lock);
2680 }
2681
2682 if (ret)
2683 break;
2684 *trimmed += actually_trimmed;
2685 }
2686 start += bytes;
2687 bytes = 0;
2688
2689 if (fatal_signal_pending(current)) {
2690 ret = -ERESTARTSYS;
2691 break;
2692 }
2693
2694 cond_resched();
2695 }
2696
2697 return ret;
2698 }
2699
2700 /*
2701 * Find the left-most item in the cache tree, and then return the
2702 * smallest inode number in the item.
2703 *
2704 * Note: the returned inode number may not be the smallest one in
2705 * the tree, if the left-most item is a bitmap.
2706 */
2707 u64 btrfs_find_ino_for_alloc(struct btrfs_root *fs_root)
2708 {
2709 struct btrfs_free_space_ctl *ctl = fs_root->free_ino_ctl;
2710 struct btrfs_free_space *entry = NULL;
2711 u64 ino = 0;
2712
2713 spin_lock(&ctl->tree_lock);
2714
2715 if (RB_EMPTY_ROOT(&ctl->free_space_offset))
2716 goto out;
2717
2718 entry = rb_entry(rb_first(&ctl->free_space_offset),
2719 struct btrfs_free_space, offset_index);
2720
2721 if (!entry->bitmap) {
2722 ino = entry->offset;
2723
2724 unlink_free_space(ctl, entry);
2725 entry->offset++;
2726 entry->bytes--;
2727 if (!entry->bytes)
2728 kmem_cache_free(btrfs_free_space_cachep, entry);
2729 else
2730 link_free_space(ctl, entry);
2731 } else {
2732 u64 offset = 0;
2733 u64 count = 1;
2734 int ret;
2735
2736 ret = search_bitmap(ctl, entry, &offset, &count);
2737 BUG_ON(ret);
2738
2739 ino = offset;
2740 bitmap_clear_bits(ctl, entry, offset, 1);
2741 if (entry->bytes == 0)
2742 free_bitmap(ctl, entry);
2743 }
2744 out:
2745 spin_unlock(&ctl->tree_lock);
2746
2747 return ino;
2748 }
2749
2750 struct inode *lookup_free_ino_inode(struct btrfs_root *root,
2751 struct btrfs_path *path)
2752 {
2753 struct inode *inode = NULL;
2754
2755 spin_lock(&root->cache_lock);
2756 if (root->cache_inode)
2757 inode = igrab(root->cache_inode);
2758 spin_unlock(&root->cache_lock);
2759 if (inode)
2760 return inode;
2761
2762 inode = __lookup_free_space_inode(root, path, 0);
2763 if (IS_ERR(inode))
2764 return inode;
2765
2766 spin_lock(&root->cache_lock);
2767 if (!btrfs_fs_closing(root->fs_info))
2768 root->cache_inode = igrab(inode);
2769 spin_unlock(&root->cache_lock);
2770
2771 return inode;
2772 }
2773
2774 int create_free_ino_inode(struct btrfs_root *root,
2775 struct btrfs_trans_handle *trans,
2776 struct btrfs_path *path)
2777 {
2778 return __create_free_space_inode(root, trans, path,
2779 BTRFS_FREE_INO_OBJECTID, 0);
2780 }
2781
2782 int load_free_ino_cache(struct btrfs_fs_info *fs_info, struct btrfs_root *root)
2783 {
2784 struct btrfs_free_space_ctl *ctl = root->free_ino_ctl;
2785 struct btrfs_path *path;
2786 struct inode *inode;
2787 int ret = 0;
2788 u64 root_gen = btrfs_root_generation(&root->root_item);
2789
2790 if (!btrfs_test_opt(root, INODE_MAP_CACHE))
2791 return 0;
2792
2793 /*
2794 * If we're unmounting then just return, since this does a search on the
2795 * normal root and not the commit root and we could deadlock.
2796 */
2797 if (btrfs_fs_closing(fs_info))
2798 return 0;
2799
2800 path = btrfs_alloc_path();
2801 if (!path)
2802 return 0;
2803
2804 inode = lookup_free_ino_inode(root, path);
2805 if (IS_ERR(inode))
2806 goto out;
2807
2808 if (root_gen != BTRFS_I(inode)->generation)
2809 goto out_put;
2810
2811 ret = __load_free_space_cache(root, inode, ctl, path, 0);
2812
2813 if (ret < 0)
2814 printk(KERN_ERR "btrfs: failed to load free ino cache for "
2815 "root %llu\n", root->root_key.objectid);
2816 out_put:
2817 iput(inode);
2818 out:
2819 btrfs_free_path(path);
2820 return ret;
2821 }
2822
2823 int btrfs_write_out_ino_cache(struct btrfs_root *root,
2824 struct btrfs_trans_handle *trans,
2825 struct btrfs_path *path)
2826 {
2827 struct btrfs_free_space_ctl *ctl = root->free_ino_ctl;
2828 struct inode *inode;
2829 int ret;
2830
2831 if (!btrfs_test_opt(root, INODE_MAP_CACHE))
2832 return 0;
2833
2834 inode = lookup_free_ino_inode(root, path);
2835 if (IS_ERR(inode))
2836 return 0;
2837
2838 ret = __btrfs_write_out_cache(root, inode, ctl, NULL, trans, path, 0);
2839 if (ret) {
2840 btrfs_delalloc_release_metadata(inode, inode->i_size);
2841 #ifdef DEBUG
2842 printk(KERN_ERR "btrfs: failed to write free ino cache "
2843 "for root %llu\n", root->root_key.objectid);
2844 #endif
2845 }
2846
2847 iput(inode);
2848 return ret;
2849 }
Linux kernel - Deliverables
This page took 0.187281 seconds and 5 git commands to generate.