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Btrfs: section mismatch warnings
[linux-2.6-block.git] / fs / btrfs / extent-tree.c
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1/*
2 * Copyright (C) 2007 Oracle. 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/sched.h>
20#include "ctree.h"
21#include "disk-io.h"
22#include "print-tree.h"
23#include "transaction.h"
24
25#define BLOCK_GROUP_DATA EXTENT_WRITEBACK
26#define BLOCK_GROUP_METADATA EXTENT_UPTODATE
27#define BLOCK_GROUP_DIRTY EXTENT_DIRTY
28
29static int finish_current_insert(struct btrfs_trans_handle *trans, struct
30 btrfs_root *extent_root);
31static int del_pending_extents(struct btrfs_trans_handle *trans, struct
32 btrfs_root *extent_root);
33
34static int cache_block_group(struct btrfs_root *root,
35 struct btrfs_block_group_cache *block_group)
36{
37 struct btrfs_path *path;
38 int ret;
39 struct btrfs_key key;
40 struct extent_buffer *leaf;
41 struct extent_map_tree *free_space_cache;
42 int slot;
43 u64 last = 0;
44 u64 hole_size;
45 u64 first_free;
46 int found = 0;
47
48 if (!block_group)
49 return 0;
50
51 root = root->fs_info->extent_root;
52 free_space_cache = &root->fs_info->free_space_cache;
53
54 if (block_group->cached)
55 return 0;
56
57 path = btrfs_alloc_path();
58 if (!path)
59 return -ENOMEM;
60
61 path->reada = 2;
62 first_free = block_group->key.objectid;
63 key.objectid = block_group->key.objectid;
64 key.offset = 0;
65
66 btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
67 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
68
69 if (ret < 0)
70 return ret;
71
72 if (ret && path->slots[0] > 0)
73 path->slots[0]--;
74
75 while(1) {
76 leaf = path->nodes[0];
77 slot = path->slots[0];
78 if (slot >= btrfs_header_nritems(leaf)) {
79 ret = btrfs_next_leaf(root, path);
80 if (ret < 0)
81 goto err;
82 if (ret == 0) {
83 continue;
84 } else {
85 break;
86 }
87 }
88
89 btrfs_item_key_to_cpu(leaf, &key, slot);
90 if (key.objectid < block_group->key.objectid) {
91 if (key.objectid + key.offset > first_free)
92 first_free = key.objectid + key.offset;
93 goto next;
94 }
95
96 if (key.objectid >= block_group->key.objectid +
97 block_group->key.offset) {
98 break;
99 }
100
101 if (btrfs_key_type(&key) == BTRFS_EXTENT_ITEM_KEY) {
102 if (!found) {
103 last = first_free;
104 found = 1;
105 }
106 if (key.objectid > last) {
107 hole_size = key.objectid - last;
108 set_extent_dirty(free_space_cache, last,
109 last + hole_size - 1,
110 GFP_NOFS);
111 }
112 last = key.objectid + key.offset;
113 }
114next:
115 path->slots[0]++;
116 }
117
118 if (!found)
119 last = first_free;
120 if (block_group->key.objectid +
121 block_group->key.offset > last) {
122 hole_size = block_group->key.objectid +
123 block_group->key.offset - last;
124 set_extent_dirty(free_space_cache, last,
125 last + hole_size - 1, GFP_NOFS);
126 }
127 block_group->cached = 1;
128err:
129 btrfs_free_path(path);
130 return 0;
131}
132
133struct btrfs_block_group_cache *btrfs_lookup_block_group(struct
134 btrfs_fs_info *info,
135 u64 bytenr)
136{
137 struct extent_map_tree *block_group_cache;
138 struct btrfs_block_group_cache *block_group = NULL;
139 u64 ptr;
140 u64 start;
141 u64 end;
142 int ret;
143
144 block_group_cache = &info->block_group_cache;
145 ret = find_first_extent_bit(block_group_cache,
146 bytenr, &start, &end,
147 BLOCK_GROUP_DATA | BLOCK_GROUP_METADATA);
148 if (ret) {
149 return NULL;
150 }
151 ret = get_state_private(block_group_cache, start, &ptr);
152 if (ret)
153 return NULL;
154
155 block_group = (struct btrfs_block_group_cache *)(unsigned long)ptr;
156 if (block_group->key.objectid <= bytenr && bytenr <
157 block_group->key.objectid + block_group->key.offset)
158 return block_group;
159 return NULL;
160}
161static u64 find_search_start(struct btrfs_root *root,
162 struct btrfs_block_group_cache **cache_ret,
163 u64 search_start, int num,
164 int data, int full_scan)
165{
166 int ret;
167 struct btrfs_block_group_cache *cache = *cache_ret;
168 u64 last;
169 u64 start = 0;
170 u64 end = 0;
171 u64 cache_miss = 0;
172 int wrapped = 0;
173
174 if (!cache) {
175 goto out;
176 }
177again:
178 ret = cache_block_group(root, cache);
179 if (ret)
180 goto out;
181
182 last = max(search_start, cache->key.objectid);
183
184 while(1) {
185 ret = find_first_extent_bit(&root->fs_info->free_space_cache,
186 last, &start, &end, EXTENT_DIRTY);
187 if (ret) {
188 if (!cache_miss)
189 cache_miss = last;
190 goto new_group;
191 }
192
193 start = max(last, start);
194 last = end + 1;
195 if (last - start < num) {
196 if (last == cache->key.objectid + cache->key.offset)
197 cache_miss = start;
198 continue;
199 }
200 if (data != BTRFS_BLOCK_GROUP_MIXED &&
201 start + num > cache->key.objectid + cache->key.offset)
202 goto new_group;
203 return start;
204 }
205out:
206 cache = btrfs_lookup_block_group(root->fs_info, search_start);
207 if (!cache) {
208 printk("Unable to find block group for %Lu\n",
209 search_start);
210 WARN_ON(1);
211 return search_start;
212 }
213 return search_start;
214
215new_group:
216 last = cache->key.objectid + cache->key.offset;
217wrapped:
218 cache = btrfs_lookup_block_group(root->fs_info, last);
219 if (!cache) {
220no_cache:
221 if (!wrapped) {
222 wrapped = 1;
223 last = search_start;
224 data = BTRFS_BLOCK_GROUP_MIXED;
225 goto wrapped;
226 }
227 goto out;
228 }
229 if (cache_miss && !cache->cached) {
230 cache_block_group(root, cache);
231 last = cache_miss;
232 cache = btrfs_lookup_block_group(root->fs_info, last);
233 }
234 cache = btrfs_find_block_group(root, cache, last, data, 0);
235 if (!cache)
236 goto no_cache;
237 *cache_ret = cache;
238 cache_miss = 0;
239 goto again;
240}
241
242static u64 div_factor(u64 num, int factor)
243{
244 if (factor == 10)
245 return num;
246 num *= factor;
247 do_div(num, 10);
248 return num;
249}
250
251struct btrfs_block_group_cache *btrfs_find_block_group(struct btrfs_root *root,
252 struct btrfs_block_group_cache
253 *hint, u64 search_start,
254 int data, int owner)
255{
256 struct btrfs_block_group_cache *cache;
257 struct extent_map_tree *block_group_cache;
258 struct btrfs_block_group_cache *found_group = NULL;
259 struct btrfs_fs_info *info = root->fs_info;
260 u64 used;
261 u64 last = 0;
262 u64 hint_last;
263 u64 start;
264 u64 end;
265 u64 free_check;
266 u64 ptr;
267 int bit;
268 int ret;
269 int full_search = 0;
270 int factor = 8;
271 int data_swap = 0;
272
273 block_group_cache = &info->block_group_cache;
274
275 if (!owner)
276 factor = 8;
277
278 if (data == BTRFS_BLOCK_GROUP_MIXED) {
279 bit = BLOCK_GROUP_DATA | BLOCK_GROUP_METADATA;
280 factor = 10;
281 } else if (data)
282 bit = BLOCK_GROUP_DATA;
283 else
284 bit = BLOCK_GROUP_METADATA;
285
286 if (search_start) {
287 struct btrfs_block_group_cache *shint;
288 shint = btrfs_lookup_block_group(info, search_start);
289 if (shint && (shint->data == data ||
290 shint->data == BTRFS_BLOCK_GROUP_MIXED)) {
291 used = btrfs_block_group_used(&shint->item);
292 if (used + shint->pinned <
293 div_factor(shint->key.offset, factor)) {
294 return shint;
295 }
296 }
297 }
298 if (hint && (hint->data == data ||
299 hint->data == BTRFS_BLOCK_GROUP_MIXED)) {
300 used = btrfs_block_group_used(&hint->item);
301 if (used + hint->pinned <
302 div_factor(hint->key.offset, factor)) {
303 return hint;
304 }
305 last = hint->key.objectid + hint->key.offset;
306 hint_last = last;
307 } else {
308 if (hint)
309 hint_last = max(hint->key.objectid, search_start);
310 else
311 hint_last = search_start;
312
313 last = hint_last;
314 }
315again:
316 while(1) {
317 ret = find_first_extent_bit(block_group_cache, last,
318 &start, &end, bit);
319 if (ret)
320 break;
321
322 ret = get_state_private(block_group_cache, start, &ptr);
323 if (ret)
324 break;
325
326 cache = (struct btrfs_block_group_cache *)(unsigned long)ptr;
327 last = cache->key.objectid + cache->key.offset;
328 used = btrfs_block_group_used(&cache->item);
329
330 if (full_search)
331 free_check = cache->key.offset;
332 else
333 free_check = div_factor(cache->key.offset, factor);
334 if (used + cache->pinned < free_check) {
335 found_group = cache;
336 goto found;
337 }
338 cond_resched();
339 }
340 if (!full_search) {
341 last = search_start;
342 full_search = 1;
343 goto again;
344 }
345 if (!data_swap) {
346 data_swap = 1;
347 bit = BLOCK_GROUP_DATA | BLOCK_GROUP_METADATA;
348 last = search_start;
349 goto again;
350 }
351found:
352 return found_group;
353}
354
355int btrfs_inc_extent_ref(struct btrfs_trans_handle *trans,
356 struct btrfs_root *root,
357 u64 bytenr, u64 num_bytes)
358{
359 struct btrfs_path *path;
360 int ret;
361 struct btrfs_key key;
362 struct extent_buffer *l;
363 struct btrfs_extent_item *item;
364 u32 refs;
365
366 WARN_ON(num_bytes < root->sectorsize);
367 path = btrfs_alloc_path();
368 if (!path)
369 return -ENOMEM;
370
371 key.objectid = bytenr;
372 btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
373 key.offset = num_bytes;
374 ret = btrfs_search_slot(trans, root->fs_info->extent_root, &key, path,
375 0, 1);
376 if (ret < 0)
377 return ret;
378 if (ret != 0) {
379 BUG();
380 }
381 BUG_ON(ret != 0);
382 l = path->nodes[0];
383 item = btrfs_item_ptr(l, path->slots[0], struct btrfs_extent_item);
384 refs = btrfs_extent_refs(l, item);
385 btrfs_set_extent_refs(l, item, refs + 1);
386 btrfs_mark_buffer_dirty(path->nodes[0]);
387
388 btrfs_release_path(root->fs_info->extent_root, path);
389 btrfs_free_path(path);
390 finish_current_insert(trans, root->fs_info->extent_root);
391 del_pending_extents(trans, root->fs_info->extent_root);
392 return 0;
393}
394
395int btrfs_extent_post_op(struct btrfs_trans_handle *trans,
396 struct btrfs_root *root)
397{
398 finish_current_insert(trans, root->fs_info->extent_root);
399 del_pending_extents(trans, root->fs_info->extent_root);
400 return 0;
401}
402
403static int lookup_extent_ref(struct btrfs_trans_handle *trans,
404 struct btrfs_root *root, u64 bytenr,
405 u64 num_bytes, u32 *refs)
406{
407 struct btrfs_path *path;
408 int ret;
409 struct btrfs_key key;
410 struct extent_buffer *l;
411 struct btrfs_extent_item *item;
412
413 WARN_ON(num_bytes < root->sectorsize);
414 path = btrfs_alloc_path();
415 key.objectid = bytenr;
416 key.offset = num_bytes;
417 btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
418 ret = btrfs_search_slot(trans, root->fs_info->extent_root, &key, path,
419 0, 0);
420 if (ret < 0)
421 goto out;
422 if (ret != 0) {
423 btrfs_print_leaf(root, path->nodes[0]);
424 printk("failed to find block number %Lu\n", bytenr);
425 BUG();
426 }
427 l = path->nodes[0];
428 item = btrfs_item_ptr(l, path->slots[0], struct btrfs_extent_item);
429 *refs = btrfs_extent_refs(l, item);
430out:
431 btrfs_free_path(path);
432 return 0;
433}
434
435int btrfs_inc_root_ref(struct btrfs_trans_handle *trans,
436 struct btrfs_root *root)
437{
438 return btrfs_inc_extent_ref(trans, root, root->node->start,
439 root->node->len);
440}
441
442int btrfs_inc_ref(struct btrfs_trans_handle *trans, struct btrfs_root *root,
443 struct extent_buffer *buf)
444{
445 u64 bytenr;
446 u32 nritems;
447 struct btrfs_key key;
448 struct btrfs_file_extent_item *fi;
449 int i;
450 int level;
451 int ret;
452 int faili;
453 int err;
454
455 if (!root->ref_cows)
456 return 0;
457
458 level = btrfs_header_level(buf);
459 nritems = btrfs_header_nritems(buf);
460 for (i = 0; i < nritems; i++) {
461 if (level == 0) {
462 u64 disk_bytenr;
463 btrfs_item_key_to_cpu(buf, &key, i);
464 if (btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY)
465 continue;
466 fi = btrfs_item_ptr(buf, i,
467 struct btrfs_file_extent_item);
468 if (btrfs_file_extent_type(buf, fi) ==
469 BTRFS_FILE_EXTENT_INLINE)
470 continue;
471 disk_bytenr = btrfs_file_extent_disk_bytenr(buf, fi);
472 if (disk_bytenr == 0)
473 continue;
474 ret = btrfs_inc_extent_ref(trans, root, disk_bytenr,
475 btrfs_file_extent_disk_num_bytes(buf, fi));
476 if (ret) {
477 faili = i;
478 goto fail;
479 }
480 } else {
481 bytenr = btrfs_node_blockptr(buf, i);
482 ret = btrfs_inc_extent_ref(trans, root, bytenr,
483 btrfs_level_size(root, level - 1));
484 if (ret) {
485 faili = i;
486 goto fail;
487 }
488 }
489 }
490 return 0;
491fail:
492 WARN_ON(1);
493 for (i =0; i < faili; i++) {
494 if (level == 0) {
495 u64 disk_bytenr;
496 btrfs_item_key_to_cpu(buf, &key, i);
497 if (btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY)
498 continue;
499 fi = btrfs_item_ptr(buf, i,
500 struct btrfs_file_extent_item);
501 if (btrfs_file_extent_type(buf, fi) ==
502 BTRFS_FILE_EXTENT_INLINE)
503 continue;
504 disk_bytenr = btrfs_file_extent_disk_bytenr(buf, fi);
505 if (disk_bytenr == 0)
506 continue;
507 err = btrfs_free_extent(trans, root, disk_bytenr,
508 btrfs_file_extent_disk_num_bytes(buf,
509 fi), 0);
510 BUG_ON(err);
511 } else {
512 bytenr = btrfs_node_blockptr(buf, i);
513 err = btrfs_free_extent(trans, root, bytenr,
514 btrfs_level_size(root, level - 1), 0);
515 BUG_ON(err);
516 }
517 }
518 return ret;
519}
520
521static int write_one_cache_group(struct btrfs_trans_handle *trans,
522 struct btrfs_root *root,
523 struct btrfs_path *path,
524 struct btrfs_block_group_cache *cache)
525{
526 int ret;
527 int pending_ret;
528 struct btrfs_root *extent_root = root->fs_info->extent_root;
529 unsigned long bi;
530 struct extent_buffer *leaf;
531
532 ret = btrfs_search_slot(trans, extent_root, &cache->key, path, 0, 1);
533 if (ret < 0)
534 goto fail;
535 BUG_ON(ret);
536
537 leaf = path->nodes[0];
538 bi = btrfs_item_ptr_offset(leaf, path->slots[0]);
539 write_extent_buffer(leaf, &cache->item, bi, sizeof(cache->item));
540 btrfs_mark_buffer_dirty(leaf);
541 btrfs_release_path(extent_root, path);
542fail:
543 finish_current_insert(trans, extent_root);
544 pending_ret = del_pending_extents(trans, extent_root);
545 if (ret)
546 return ret;
547 if (pending_ret)
548 return pending_ret;
549 return 0;
550
551}
552
553int btrfs_write_dirty_block_groups(struct btrfs_trans_handle *trans,
554 struct btrfs_root *root)
555{
556 struct extent_map_tree *block_group_cache;
557 struct btrfs_block_group_cache *cache;
558 int ret;
559 int err = 0;
560 int werr = 0;
561 struct btrfs_path *path;
562 u64 last = 0;
563 u64 start;
564 u64 end;
565 u64 ptr;
566
567 block_group_cache = &root->fs_info->block_group_cache;
568 path = btrfs_alloc_path();
569 if (!path)
570 return -ENOMEM;
571
572 while(1) {
573 ret = find_first_extent_bit(block_group_cache, last,
574 &start, &end, BLOCK_GROUP_DIRTY);
575 if (ret)
576 break;
577
578 last = end + 1;
579 ret = get_state_private(block_group_cache, start, &ptr);
580 if (ret)
581 break;
582
583 cache = (struct btrfs_block_group_cache *)(unsigned long)ptr;
584 err = write_one_cache_group(trans, root,
585 path, cache);
586 /*
587 * if we fail to write the cache group, we want
588 * to keep it marked dirty in hopes that a later
589 * write will work
590 */
591 if (err) {
592 werr = err;
593 continue;
594 }
595 clear_extent_bits(block_group_cache, start, end,
596 BLOCK_GROUP_DIRTY, GFP_NOFS);
597 }
598 btrfs_free_path(path);
599 return werr;
600}
601
602static int update_block_group(struct btrfs_trans_handle *trans,
603 struct btrfs_root *root,
604 u64 bytenr, u64 num_bytes, int alloc,
605 int mark_free, int data)
606{
607 struct btrfs_block_group_cache *cache;
608 struct btrfs_fs_info *info = root->fs_info;
609 u64 total = num_bytes;
610 u64 old_val;
611 u64 byte_in_group;
612 u64 start;
613 u64 end;
614
615 while(total) {
616 cache = btrfs_lookup_block_group(info, bytenr);
617 if (!cache) {
618 return -1;
619 }
620 byte_in_group = bytenr - cache->key.objectid;
621 WARN_ON(byte_in_group > cache->key.offset);
622 start = cache->key.objectid;
623 end = start + cache->key.offset - 1;
624 set_extent_bits(&info->block_group_cache, start, end,
625 BLOCK_GROUP_DIRTY, GFP_NOFS);
626
627 old_val = btrfs_block_group_used(&cache->item);
628 num_bytes = min(total, cache->key.offset - byte_in_group);
629 if (alloc) {
630 if (cache->data != data &&
631 old_val < (cache->key.offset >> 1)) {
632 int bit_to_clear;
633 int bit_to_set;
634 cache->data = data;
635 if (data) {
636 bit_to_clear = BLOCK_GROUP_METADATA;
637 bit_to_set = BLOCK_GROUP_DATA;
638 cache->item.flags &=
639 ~BTRFS_BLOCK_GROUP_MIXED;
640 cache->item.flags |=
641 BTRFS_BLOCK_GROUP_DATA;
642 } else {
643 bit_to_clear = BLOCK_GROUP_DATA;
644 bit_to_set = BLOCK_GROUP_METADATA;
645 cache->item.flags &=
646 ~BTRFS_BLOCK_GROUP_MIXED;
647 cache->item.flags &=
648 ~BTRFS_BLOCK_GROUP_DATA;
649 }
650 clear_extent_bits(&info->block_group_cache,
651 start, end, bit_to_clear,
652 GFP_NOFS);
653 set_extent_bits(&info->block_group_cache,
654 start, end, bit_to_set,
655 GFP_NOFS);
656 } else if (cache->data != data &&
657 cache->data != BTRFS_BLOCK_GROUP_MIXED) {
658 cache->data = BTRFS_BLOCK_GROUP_MIXED;
659 set_extent_bits(&info->block_group_cache,
660 start, end,
661 BLOCK_GROUP_DATA |
662 BLOCK_GROUP_METADATA,
663 GFP_NOFS);
664 }
665 old_val += num_bytes;
666 } else {
667 old_val -= num_bytes;
668 if (mark_free) {
669 set_extent_dirty(&info->free_space_cache,
670 bytenr, bytenr + num_bytes - 1,
671 GFP_NOFS);
672 }
673 }
674 btrfs_set_block_group_used(&cache->item, old_val);
675 total -= num_bytes;
676 bytenr += num_bytes;
677 }
678 return 0;
679}
680static int update_pinned_extents(struct btrfs_root *root,
681 u64 bytenr, u64 num, int pin)
682{
683 u64 len;
684 struct btrfs_block_group_cache *cache;
685 struct btrfs_fs_info *fs_info = root->fs_info;
686
687 if (pin) {
688 set_extent_dirty(&fs_info->pinned_extents,
689 bytenr, bytenr + num - 1, GFP_NOFS);
690 } else {
691 clear_extent_dirty(&fs_info->pinned_extents,
692 bytenr, bytenr + num - 1, GFP_NOFS);
693 }
694 while (num > 0) {
695 cache = btrfs_lookup_block_group(fs_info, bytenr);
696 WARN_ON(!cache);
697 len = min(num, cache->key.offset -
698 (bytenr - cache->key.objectid));
699 if (pin) {
700 cache->pinned += len;
701 fs_info->total_pinned += len;
702 } else {
703 cache->pinned -= len;
704 fs_info->total_pinned -= len;
705 }
706 bytenr += len;
707 num -= len;
708 }
709 return 0;
710}
711
712int btrfs_copy_pinned(struct btrfs_root *root, struct extent_map_tree *copy)
713{
714 u64 last = 0;
715 u64 start;
716 u64 end;
717 struct extent_map_tree *pinned_extents = &root->fs_info->pinned_extents;
718 int ret;
719
720 while(1) {
721 ret = find_first_extent_bit(pinned_extents, last,
722 &start, &end, EXTENT_DIRTY);
723 if (ret)
724 break;
725 set_extent_dirty(copy, start, end, GFP_NOFS);
726 last = end + 1;
727 }
728 return 0;
729}
730
731int btrfs_finish_extent_commit(struct btrfs_trans_handle *trans,
732 struct btrfs_root *root,
733 struct extent_map_tree *unpin)
734{
735 u64 start;
736 u64 end;
737 int ret;
738 struct extent_map_tree *free_space_cache;
739 free_space_cache = &root->fs_info->free_space_cache;
740
741 while(1) {
742 ret = find_first_extent_bit(unpin, 0, &start, &end,
743 EXTENT_DIRTY);
744 if (ret)
745 break;
746 update_pinned_extents(root, start, end + 1 - start, 0);
747 clear_extent_dirty(unpin, start, end, GFP_NOFS);
748 set_extent_dirty(free_space_cache, start, end, GFP_NOFS);
749 }
750 return 0;
751}
752
753static int finish_current_insert(struct btrfs_trans_handle *trans, struct
754 btrfs_root *extent_root)
755{
756 struct btrfs_key ins;
757 struct btrfs_extent_item extent_item;
758 int ret;
759 int err = 0;
760 u64 start;
761 u64 end;
762 struct btrfs_fs_info *info = extent_root->fs_info;
763
764 btrfs_set_stack_extent_refs(&extent_item, 1);
765 btrfs_set_key_type(&ins, BTRFS_EXTENT_ITEM_KEY);
766 btrfs_set_stack_extent_owner(&extent_item,
767 extent_root->root_key.objectid);
768
769 while(1) {
770 ret = find_first_extent_bit(&info->extent_ins, 0, &start,
771 &end, EXTENT_LOCKED);
772 if (ret)
773 break;
774
775 ins.objectid = start;
776 ins.offset = end + 1 - start;
777 err = btrfs_insert_item(trans, extent_root, &ins,
778 &extent_item, sizeof(extent_item));
779 clear_extent_bits(&info->extent_ins, start, end, EXTENT_LOCKED,
780 GFP_NOFS);
781 }
782 return 0;
783}
784
785static int pin_down_bytes(struct btrfs_root *root, u64 bytenr, u32 num_bytes,
786 int pending)
787{
788 int err = 0;
789 struct extent_buffer *buf;
790
791 if (!pending) {
792 buf = btrfs_find_tree_block(root, bytenr, num_bytes);
793 if (buf) {
794 if (btrfs_buffer_uptodate(buf)) {
795 u64 transid =
796 root->fs_info->running_transaction->transid;
797 if (btrfs_header_generation(buf) == transid) {
798 free_extent_buffer(buf);
799 return 1;
800 }
801 }
802 free_extent_buffer(buf);
803 }
804 update_pinned_extents(root, bytenr, num_bytes, 1);
805 } else {
806 set_extent_bits(&root->fs_info->pending_del,
807 bytenr, bytenr + num_bytes - 1,
808 EXTENT_LOCKED, GFP_NOFS);
809 }
810 BUG_ON(err < 0);
811 return 0;
812}
813
814/*
815 * remove an extent from the root, returns 0 on success
816 */
817static int __free_extent(struct btrfs_trans_handle *trans, struct btrfs_root
818 *root, u64 bytenr, u64 num_bytes, int pin,
819 int mark_free)
820{
821 struct btrfs_path *path;
822 struct btrfs_key key;
823 struct btrfs_fs_info *info = root->fs_info;
824 struct btrfs_root *extent_root = info->extent_root;
825 struct extent_buffer *leaf;
826 int ret;
827 struct btrfs_extent_item *ei;
828 u32 refs;
829
830 key.objectid = bytenr;
831 btrfs_set_key_type(&key, BTRFS_EXTENT_ITEM_KEY);
832 key.offset = num_bytes;
833
834 path = btrfs_alloc_path();
835 if (!path)
836 return -ENOMEM;
837
838 ret = btrfs_search_slot(trans, extent_root, &key, path, -1, 1);
839 if (ret < 0)
840 return ret;
841 BUG_ON(ret);
842
843 leaf = path->nodes[0];
844 ei = btrfs_item_ptr(leaf, path->slots[0],
845 struct btrfs_extent_item);
846 refs = btrfs_extent_refs(leaf, ei);
847 BUG_ON(refs == 0);
848 refs -= 1;
849 btrfs_set_extent_refs(leaf, ei, refs);
850 btrfs_mark_buffer_dirty(leaf);
851
852 if (refs == 0) {
853 u64 super_used;
854 u64 root_used;
855
856 if (pin) {
857 ret = pin_down_bytes(root, bytenr, num_bytes, 0);
858 if (ret > 0)
859 mark_free = 1;
860 BUG_ON(ret < 0);
861 }
862
863 /* block accounting for super block */
864 super_used = btrfs_super_bytes_used(&info->super_copy);
865 btrfs_set_super_bytes_used(&info->super_copy,
866 super_used - num_bytes);
867
868 /* block accounting for root item */
869 root_used = btrfs_root_used(&root->root_item);
870 btrfs_set_root_used(&root->root_item,
871 root_used - num_bytes);
872
873 ret = btrfs_del_item(trans, extent_root, path);
874 if (ret) {
875 return ret;
876 }
877 ret = update_block_group(trans, root, bytenr, num_bytes, 0,
878 mark_free, 0);
879 BUG_ON(ret);
880 }
881 btrfs_free_path(path);
882 finish_current_insert(trans, extent_root);
883 return ret;
884}
885
886/*
887 * find all the blocks marked as pending in the radix tree and remove
888 * them from the extent map
889 */
890static int del_pending_extents(struct btrfs_trans_handle *trans, struct
891 btrfs_root *extent_root)
892{
893 int ret;
894 int err = 0;
895 u64 start;
896 u64 end;
897 struct extent_map_tree *pending_del;
898 struct extent_map_tree *pinned_extents;
899
900 pending_del = &extent_root->fs_info->pending_del;
901 pinned_extents = &extent_root->fs_info->pinned_extents;
902
903 while(1) {
904 ret = find_first_extent_bit(pending_del, 0, &start, &end,
905 EXTENT_LOCKED);
906 if (ret)
907 break;
908 update_pinned_extents(extent_root, start, end + 1 - start, 1);
909 clear_extent_bits(pending_del, start, end, EXTENT_LOCKED,
910 GFP_NOFS);
911 ret = __free_extent(trans, extent_root,
912 start, end + 1 - start, 0, 0);
913 if (ret)
914 err = ret;
915 }
916 return err;
917}
918
919/*
920 * remove an extent from the root, returns 0 on success
921 */
922int btrfs_free_extent(struct btrfs_trans_handle *trans, struct btrfs_root
923 *root, u64 bytenr, u64 num_bytes, int pin)
924{
925 struct btrfs_root *extent_root = root->fs_info->extent_root;
926 int pending_ret;
927 int ret;
928
929 WARN_ON(num_bytes < root->sectorsize);
930 if (root == extent_root) {
931 pin_down_bytes(root, bytenr, num_bytes, 1);
932 return 0;
933 }
934 ret = __free_extent(trans, root, bytenr, num_bytes, pin, pin == 0);
935 pending_ret = del_pending_extents(trans, root->fs_info->extent_root);
936 return ret ? ret : pending_ret;
937}
938
939static u64 stripe_align(struct btrfs_root *root, u64 val)
940{
941 u64 mask = ((u64)root->stripesize - 1);
942 u64 ret = (val + mask) & ~mask;
943 return ret;
944}
945
946/*
947 * walks the btree of allocated extents and find a hole of a given size.
948 * The key ins is changed to record the hole:
949 * ins->objectid == block start
950 * ins->flags = BTRFS_EXTENT_ITEM_KEY
951 * ins->offset == number of blocks
952 * Any available blocks before search_start are skipped.
953 */
954static int find_free_extent(struct btrfs_trans_handle *trans, struct btrfs_root
955 *orig_root, u64 num_bytes, u64 empty_size,
956 u64 search_start, u64 search_end, u64 hint_byte,
957 struct btrfs_key *ins, u64 exclude_start,
958 u64 exclude_nr, int data)
959{
960 struct btrfs_path *path;
961 struct btrfs_key key;
962 u64 hole_size = 0;
963 u64 aligned;
964 int ret;
965 int slot = 0;
966 u64 last_byte = 0;
967 u64 orig_search_start = search_start;
968 int start_found;
969 struct extent_buffer *l;
970 struct btrfs_root * root = orig_root->fs_info->extent_root;
971 struct btrfs_fs_info *info = root->fs_info;
972 u64 total_needed = num_bytes;
973 int level;
974 struct btrfs_block_group_cache *block_group;
975 int full_scan = 0;
976 int wrapped = 0;
977 u64 cached_start;
978
979 WARN_ON(num_bytes < root->sectorsize);
980 btrfs_set_key_type(ins, BTRFS_EXTENT_ITEM_KEY);
981
982 level = btrfs_header_level(root->node);
983
984 if (num_bytes >= 32 * 1024 * 1024 && hint_byte) {
985 data = BTRFS_BLOCK_GROUP_MIXED;
986 }
987
988 if (search_end == (u64)-1)
989 search_end = btrfs_super_total_bytes(&info->super_copy);
990 if (hint_byte) {
991 block_group = btrfs_lookup_block_group(info, hint_byte);
992 if (!block_group)
993 hint_byte = search_start;
994 block_group = btrfs_find_block_group(root, block_group,
995 hint_byte, data, 1);
996 } else {
997 block_group = btrfs_find_block_group(root,
998 trans->block_group,
999 search_start, data, 1);
1000 }
1001
1002 total_needed += empty_size;
1003 path = btrfs_alloc_path();
1004check_failed:
1005 search_start = find_search_start(root, &block_group, search_start,
1006 total_needed, data, full_scan);
1007 search_start = stripe_align(root, search_start);
1008 cached_start = search_start;
1009 btrfs_init_path(path);
1010 ins->objectid = search_start;
1011 ins->offset = 0;
1012 start_found = 0;
1013 path->reada = 2;
1014
1015 ret = btrfs_search_slot(trans, root, ins, path, 0, 0);
1016 if (ret < 0)
1017 goto error;
1018
1019 if (path->slots[0] > 0) {
1020 path->slots[0]--;
1021 }
1022
1023 l = path->nodes[0];
1024 btrfs_item_key_to_cpu(l, &key, path->slots[0]);
1025
1026 /*
1027 * a rare case, go back one key if we hit a block group item
1028 * instead of an extent item
1029 */
1030 if (btrfs_key_type(&key) != BTRFS_EXTENT_ITEM_KEY &&
1031 key.objectid + key.offset >= search_start) {
1032 ins->objectid = key.objectid;
1033 ins->offset = key.offset - 1;
1034 btrfs_release_path(root, path);
1035 ret = btrfs_search_slot(trans, root, ins, path, 0, 0);
1036 if (ret < 0)
1037 goto error;
1038
1039 if (path->slots[0] > 0) {
1040 path->slots[0]--;
1041 }
1042 }
1043
1044 while (1) {
1045 l = path->nodes[0];
1046 slot = path->slots[0];
1047 if (slot >= btrfs_header_nritems(l)) {
1048 ret = btrfs_next_leaf(root, path);
1049 if (ret == 0)
1050 continue;
1051 if (ret < 0)
1052 goto error;
1053
1054 search_start = max(search_start,
1055 block_group->key.objectid);
1056 if (!start_found) {
1057 aligned = stripe_align(root, search_start);
1058 ins->objectid = aligned;
1059 if (aligned >= search_end) {
1060 ret = -ENOSPC;
1061 goto error;
1062 }
1063 ins->offset = search_end - aligned;
1064 start_found = 1;
1065 goto check_pending;
1066 }
1067 ins->objectid = stripe_align(root,
1068 last_byte > search_start ?
1069 last_byte : search_start);
1070 if (search_end <= ins->objectid) {
1071 ret = -ENOSPC;
1072 goto error;
1073 }
1074 ins->offset = search_end - ins->objectid;
1075 BUG_ON(ins->objectid >= search_end);
1076 goto check_pending;
1077 }
1078 btrfs_item_key_to_cpu(l, &key, slot);
1079
1080 if (key.objectid >= search_start && key.objectid > last_byte &&
1081 start_found) {
1082 if (last_byte < search_start)
1083 last_byte = search_start;
1084 aligned = stripe_align(root, last_byte);
1085 hole_size = key.objectid - aligned;
1086 if (key.objectid > aligned && hole_size >= num_bytes) {
1087 ins->objectid = aligned;
1088 ins->offset = hole_size;
1089 goto check_pending;
1090 }
1091 }
1092 if (btrfs_key_type(&key) != BTRFS_EXTENT_ITEM_KEY) {
1093 if (!start_found) {
1094 last_byte = key.objectid;
1095 start_found = 1;
1096 }
1097 goto next;
1098 }
1099
1100
1101 start_found = 1;
1102 last_byte = key.objectid + key.offset;
1103
1104 if (!full_scan && data != BTRFS_BLOCK_GROUP_MIXED &&
1105 last_byte >= block_group->key.objectid +
1106 block_group->key.offset) {
1107 btrfs_release_path(root, path);
1108 search_start = block_group->key.objectid +
1109 block_group->key.offset;
1110 goto new_group;
1111 }
1112next:
1113 path->slots[0]++;
1114 cond_resched();
1115 }
1116check_pending:
1117 /* we have to make sure we didn't find an extent that has already
1118 * been allocated by the map tree or the original allocation
1119 */
1120 btrfs_release_path(root, path);
1121 BUG_ON(ins->objectid < search_start);
1122
1123 if (ins->objectid + num_bytes >= search_end)
1124 goto enospc;
1125 if (!full_scan && data != BTRFS_BLOCK_GROUP_MIXED &&
1126 ins->objectid + num_bytes > block_group->
1127 key.objectid + block_group->key.offset) {
1128 search_start = block_group->key.objectid +
1129 block_group->key.offset;
1130 goto new_group;
1131 }
1132 if (test_range_bit(&info->extent_ins, ins->objectid,
1133 ins->objectid + num_bytes -1, EXTENT_LOCKED, 0)) {
1134 search_start = ins->objectid + num_bytes;
1135 goto new_group;
1136 }
1137 if (test_range_bit(&info->pinned_extents, ins->objectid,
1138 ins->objectid + num_bytes -1, EXTENT_DIRTY, 0)) {
1139 search_start = ins->objectid + num_bytes;
1140 goto new_group;
1141 }
1142 if (exclude_nr > 0 && (ins->objectid + num_bytes > exclude_start &&
1143 ins->objectid < exclude_start + exclude_nr)) {
1144 search_start = exclude_start + exclude_nr;
1145 goto new_group;
1146 }
1147 if (!data) {
1148 block_group = btrfs_lookup_block_group(info, ins->objectid);
1149 if (block_group)
1150 trans->block_group = block_group;
1151 }
1152 ins->offset = num_bytes;
1153 btrfs_free_path(path);
1154 return 0;
1155
1156new_group:
1157 if (search_start + num_bytes >= search_end) {
1158enospc:
1159 search_start = orig_search_start;
1160 if (full_scan) {
1161 ret = -ENOSPC;
1162 goto error;
1163 }
1164 if (wrapped) {
1165 if (!full_scan)
1166 total_needed -= empty_size;
1167 full_scan = 1;
1168 data = BTRFS_BLOCK_GROUP_MIXED;
1169 } else
1170 wrapped = 1;
1171 }
1172 block_group = btrfs_lookup_block_group(info, search_start);
1173 cond_resched();
1174 block_group = btrfs_find_block_group(root, block_group,
1175 search_start, data, 0);
1176 goto check_failed;
1177
1178error:
1179 btrfs_release_path(root, path);
1180 btrfs_free_path(path);
1181 return ret;
1182}
1183/*
1184 * finds a free extent and does all the dirty work required for allocation
1185 * returns the key for the extent through ins, and a tree buffer for
1186 * the first block of the extent through buf.
1187 *
1188 * returns 0 if everything worked, non-zero otherwise.
1189 */
1190int btrfs_alloc_extent(struct btrfs_trans_handle *trans,
1191 struct btrfs_root *root, u64 owner,
1192 u64 num_bytes, u64 empty_size, u64 hint_byte,
1193 u64 search_end, struct btrfs_key *ins, int data)
1194{
1195 int ret;
1196 int pending_ret;
1197 u64 super_used, root_used;
1198 u64 search_start = 0;
1199 struct btrfs_fs_info *info = root->fs_info;
1200 struct btrfs_root *extent_root = info->extent_root;
1201 struct btrfs_extent_item extent_item;
1202
1203 btrfs_set_stack_extent_refs(&extent_item, 1);
1204 btrfs_set_stack_extent_owner(&extent_item, owner);
1205
1206 WARN_ON(num_bytes < root->sectorsize);
1207 ret = find_free_extent(trans, root, num_bytes, empty_size,
1208 search_start, search_end, hint_byte, ins,
1209 trans->alloc_exclude_start,
1210 trans->alloc_exclude_nr, data);
1211 BUG_ON(ret);
1212 if (ret)
1213 return ret;
1214
1215 /* block accounting for super block */
1216 super_used = btrfs_super_bytes_used(&info->super_copy);
1217 btrfs_set_super_bytes_used(&info->super_copy, super_used + num_bytes);
1218
1219 /* block accounting for root item */
1220 root_used = btrfs_root_used(&root->root_item);
1221 btrfs_set_root_used(&root->root_item, root_used + num_bytes);
1222
1223 clear_extent_dirty(&root->fs_info->free_space_cache,
1224 ins->objectid, ins->objectid + ins->offset - 1,
1225 GFP_NOFS);
1226
1227 if (root == extent_root) {
1228 set_extent_bits(&root->fs_info->extent_ins, ins->objectid,
1229 ins->objectid + ins->offset - 1,
1230 EXTENT_LOCKED, GFP_NOFS);
1231 WARN_ON(data == 1);
1232 goto update_block;
1233 }
1234
1235 WARN_ON(trans->alloc_exclude_nr);
1236 trans->alloc_exclude_start = ins->objectid;
1237 trans->alloc_exclude_nr = ins->offset;
1238 ret = btrfs_insert_item(trans, extent_root, ins, &extent_item,
1239 sizeof(extent_item));
1240
1241 trans->alloc_exclude_start = 0;
1242 trans->alloc_exclude_nr = 0;
1243
1244 BUG_ON(ret);
1245 finish_current_insert(trans, extent_root);
1246 pending_ret = del_pending_extents(trans, extent_root);
1247
1248 if (ret) {
1249 return ret;
1250 }
1251 if (pending_ret) {
1252 return pending_ret;
1253 }
1254
1255update_block:
1256 ret = update_block_group(trans, root, ins->objectid, ins->offset, 1, 0,
1257 data);
1258 BUG_ON(ret);
1259 return 0;
1260}
1261
1262/*
1263 * helper function to allocate a block for a given tree
1264 * returns the tree buffer or NULL.
1265 */
1266struct extent_buffer *btrfs_alloc_free_block(struct btrfs_trans_handle *trans,
1267 struct btrfs_root *root,
1268 u32 blocksize, u64 hint,
1269 u64 empty_size)
1270{
1271 struct btrfs_key ins;
1272 int ret;
1273 struct extent_buffer *buf;
1274
1275 ret = btrfs_alloc_extent(trans, root, root->root_key.objectid,
1276 blocksize, empty_size, hint,
1277 (u64)-1, &ins, 0);
1278 if (ret) {
1279 BUG_ON(ret > 0);
1280 return ERR_PTR(ret);
1281 }
1282 buf = btrfs_find_create_tree_block(root, ins.objectid, blocksize);
1283 if (!buf) {
1284 btrfs_free_extent(trans, root, ins.objectid, blocksize, 0);
1285 return ERR_PTR(-ENOMEM);
1286 }
1287 btrfs_set_buffer_uptodate(buf);
1288 set_extent_dirty(&trans->transaction->dirty_pages, buf->start,
1289 buf->start + buf->len - 1, GFP_NOFS);
1290 set_extent_bits(&BTRFS_I(root->fs_info->btree_inode)->extent_tree,
1291 buf->start, buf->start + buf->len - 1,
1292 EXTENT_CSUM, GFP_NOFS);
1293 buf->flags |= EXTENT_CSUM;
1294 btrfs_set_buffer_defrag(buf);
1295 trans->blocks_used++;
1296 return buf;
1297}
1298
1299static int drop_leaf_ref(struct btrfs_trans_handle *trans,
1300 struct btrfs_root *root, struct extent_buffer *leaf)
1301{
1302 struct btrfs_key key;
1303 struct btrfs_file_extent_item *fi;
1304 int i;
1305 int nritems;
1306 int ret;
1307
1308 BUG_ON(!btrfs_is_leaf(leaf));
1309 nritems = btrfs_header_nritems(leaf);
1310 for (i = 0; i < nritems; i++) {
1311 u64 disk_bytenr;
1312
1313 btrfs_item_key_to_cpu(leaf, &key, i);
1314 if (btrfs_key_type(&key) != BTRFS_EXTENT_DATA_KEY)
1315 continue;
1316 fi = btrfs_item_ptr(leaf, i, struct btrfs_file_extent_item);
1317 if (btrfs_file_extent_type(leaf, fi) ==
1318 BTRFS_FILE_EXTENT_INLINE)
1319 continue;
1320 /*
1321 * FIXME make sure to insert a trans record that
1322 * repeats the snapshot del on crash
1323 */
1324 disk_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1325 if (disk_bytenr == 0)
1326 continue;
1327 ret = btrfs_free_extent(trans, root, disk_bytenr,
1328 btrfs_file_extent_disk_num_bytes(leaf, fi), 0);
1329 BUG_ON(ret);
1330 }
1331 return 0;
1332}
1333
1334static void reada_walk_down(struct btrfs_root *root,
1335 struct extent_buffer *node)
1336{
1337 int i;
1338 u32 nritems;
1339 u64 bytenr;
1340 int ret;
1341 u32 refs;
1342 int level;
1343 u32 blocksize;
1344
1345 nritems = btrfs_header_nritems(node);
1346 level = btrfs_header_level(node);
1347 for (i = 0; i < nritems; i++) {
1348 bytenr = btrfs_node_blockptr(node, i);
1349 blocksize = btrfs_level_size(root, level - 1);
1350 ret = lookup_extent_ref(NULL, root, bytenr, blocksize, &refs);
1351 BUG_ON(ret);
1352 if (refs != 1)
1353 continue;
1354 mutex_unlock(&root->fs_info->fs_mutex);
1355 ret = readahead_tree_block(root, bytenr, blocksize);
1356 cond_resched();
1357 mutex_lock(&root->fs_info->fs_mutex);
1358 if (ret)
1359 break;
1360 }
1361}
1362
1363/*
1364 * helper function for drop_snapshot, this walks down the tree dropping ref
1365 * counts as it goes.
1366 */
1367static int walk_down_tree(struct btrfs_trans_handle *trans, struct btrfs_root
1368 *root, struct btrfs_path *path, int *level)
1369{
1370 struct extent_buffer *next;
1371 struct extent_buffer *cur;
1372 u64 bytenr;
1373 u32 blocksize;
1374 int ret;
1375 u32 refs;
1376
1377 WARN_ON(*level < 0);
1378 WARN_ON(*level >= BTRFS_MAX_LEVEL);
1379 ret = lookup_extent_ref(trans, root,
1380 path->nodes[*level]->start,
1381 path->nodes[*level]->len, &refs);
1382 BUG_ON(ret);
1383 if (refs > 1)
1384 goto out;
1385
1386 /*
1387 * walk down to the last node level and free all the leaves
1388 */
1389 while(*level >= 0) {
1390 WARN_ON(*level < 0);
1391 WARN_ON(*level >= BTRFS_MAX_LEVEL);
1392 cur = path->nodes[*level];
1393
1394 if (*level > 0 && path->slots[*level] == 0)
1395 reada_walk_down(root, cur);
1396
1397 if (btrfs_header_level(cur) != *level)
1398 WARN_ON(1);
1399
1400 if (path->slots[*level] >=
1401 btrfs_header_nritems(cur))
1402 break;
1403 if (*level == 0) {
1404 ret = drop_leaf_ref(trans, root, cur);
1405 BUG_ON(ret);
1406 break;
1407 }
1408 bytenr = btrfs_node_blockptr(cur, path->slots[*level]);
1409 blocksize = btrfs_level_size(root, *level - 1);
1410 ret = lookup_extent_ref(trans, root, bytenr, blocksize, &refs);
1411 BUG_ON(ret);
1412 if (refs != 1) {
1413 path->slots[*level]++;
1414 ret = btrfs_free_extent(trans, root, bytenr,
1415 blocksize, 1);
1416 BUG_ON(ret);
1417 continue;
1418 }
1419 next = btrfs_find_tree_block(root, bytenr, blocksize);
1420 if (!next || !btrfs_buffer_uptodate(next)) {
1421 free_extent_buffer(next);
1422 mutex_unlock(&root->fs_info->fs_mutex);
1423 next = read_tree_block(root, bytenr, blocksize);
1424 mutex_lock(&root->fs_info->fs_mutex);
1425
1426 /* we dropped the lock, check one more time */
1427 ret = lookup_extent_ref(trans, root, bytenr,
1428 blocksize, &refs);
1429 BUG_ON(ret);
1430 if (refs != 1) {
1431 path->slots[*level]++;
1432 free_extent_buffer(next);
1433 ret = btrfs_free_extent(trans, root,
1434 bytenr, blocksize, 1);
1435 BUG_ON(ret);
1436 continue;
1437 }
1438 }
1439 WARN_ON(*level <= 0);
1440 if (path->nodes[*level-1])
1441 free_extent_buffer(path->nodes[*level-1]);
1442 path->nodes[*level-1] = next;
1443 *level = btrfs_header_level(next);
1444 path->slots[*level] = 0;
1445 }
1446out:
1447 WARN_ON(*level < 0);
1448 WARN_ON(*level >= BTRFS_MAX_LEVEL);
1449 ret = btrfs_free_extent(trans, root, path->nodes[*level]->start,
1450 path->nodes[*level]->len, 1);
1451 free_extent_buffer(path->nodes[*level]);
1452 path->nodes[*level] = NULL;
1453 *level += 1;
1454 BUG_ON(ret);
1455 return 0;
1456}
1457
1458/*
1459 * helper for dropping snapshots. This walks back up the tree in the path
1460 * to find the first node higher up where we haven't yet gone through
1461 * all the slots
1462 */
1463static int walk_up_tree(struct btrfs_trans_handle *trans, struct btrfs_root
1464 *root, struct btrfs_path *path, int *level)
1465{
1466 int i;
1467 int slot;
1468 int ret;
1469 struct btrfs_root_item *root_item = &root->root_item;
1470
1471 for(i = *level; i < BTRFS_MAX_LEVEL - 1 && path->nodes[i]; i++) {
1472 slot = path->slots[i];
1473 if (slot < btrfs_header_nritems(path->nodes[i]) - 1) {
1474 struct extent_buffer *node;
1475 struct btrfs_disk_key disk_key;
1476 node = path->nodes[i];
1477 path->slots[i]++;
1478 *level = i;
1479 WARN_ON(*level == 0);
1480 btrfs_node_key(node, &disk_key, path->slots[i]);
1481 memcpy(&root_item->drop_progress,
1482 &disk_key, sizeof(disk_key));
1483 root_item->drop_level = i;
1484 return 0;
1485 } else {
1486 ret = btrfs_free_extent(trans, root,
1487 path->nodes[*level]->start,
1488 path->nodes[*level]->len, 1);
1489 BUG_ON(ret);
1490 free_extent_buffer(path->nodes[*level]);
1491 path->nodes[*level] = NULL;
1492 *level = i + 1;
1493 }
1494 }
1495 return 1;
1496}
1497
1498/*
1499 * drop the reference count on the tree rooted at 'snap'. This traverses
1500 * the tree freeing any blocks that have a ref count of zero after being
1501 * decremented.
1502 */
1503int btrfs_drop_snapshot(struct btrfs_trans_handle *trans, struct btrfs_root
1504 *root)
1505{
1506 int ret = 0;
1507 int wret;
1508 int level;
1509 struct btrfs_path *path;
1510 int i;
1511 int orig_level;
1512 struct btrfs_root_item *root_item = &root->root_item;
1513
1514 path = btrfs_alloc_path();
1515 BUG_ON(!path);
1516
1517 level = btrfs_header_level(root->node);
1518 orig_level = level;
1519 if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {
1520 path->nodes[level] = root->node;
1521 extent_buffer_get(root->node);
1522 path->slots[level] = 0;
1523 } else {
1524 struct btrfs_key key;
1525 struct btrfs_disk_key found_key;
1526 struct extent_buffer *node;
1527
1528 btrfs_disk_key_to_cpu(&key, &root_item->drop_progress);
1529 level = root_item->drop_level;
1530 path->lowest_level = level;
1531 wret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
1532 if (wret < 0) {
1533 ret = wret;
1534 goto out;
1535 }
1536 node = path->nodes[level];
1537 btrfs_node_key(node, &found_key, path->slots[level]);
1538 WARN_ON(memcmp(&found_key, &root_item->drop_progress,
1539 sizeof(found_key)));
1540 }
1541 while(1) {
1542 wret = walk_down_tree(trans, root, path, &level);
1543 if (wret > 0)
1544 break;
1545 if (wret < 0)
1546 ret = wret;
1547
1548 wret = walk_up_tree(trans, root, path, &level);
1549 if (wret > 0)
1550 break;
1551 if (wret < 0)
1552 ret = wret;
1553 ret = -EAGAIN;
1554 break;
1555 }
1556 for (i = 0; i <= orig_level; i++) {
1557 if (path->nodes[i]) {
1558 free_extent_buffer(path->nodes[i]);
1559 path->nodes[i] = NULL;
1560 }
1561 }
1562out:
1563 btrfs_free_path(path);
1564 return ret;
1565}
1566
1567int btrfs_free_block_groups(struct btrfs_fs_info *info)
1568{
1569 u64 start;
1570 u64 end;
1571 u64 ptr;
1572 int ret;
1573 while(1) {
1574 ret = find_first_extent_bit(&info->block_group_cache, 0,
1575 &start, &end, (unsigned int)-1);
1576 if (ret)
1577 break;
1578 ret = get_state_private(&info->block_group_cache, start, &ptr);
1579 if (!ret)
1580 kfree((void *)(unsigned long)ptr);
1581 clear_extent_bits(&info->block_group_cache, start,
1582 end, (unsigned int)-1, GFP_NOFS);
1583 }
1584 while(1) {
1585 ret = find_first_extent_bit(&info->free_space_cache, 0,
1586 &start, &end, EXTENT_DIRTY);
1587 if (ret)
1588 break;
1589 clear_extent_dirty(&info->free_space_cache, start,
1590 end, GFP_NOFS);
1591 }
1592 return 0;
1593}
1594
1595int btrfs_read_block_groups(struct btrfs_root *root)
1596{
1597 struct btrfs_path *path;
1598 int ret;
1599 int err = 0;
1600 int bit;
1601 struct btrfs_block_group_cache *cache;
1602 struct btrfs_fs_info *info = root->fs_info;
1603 struct extent_map_tree *block_group_cache;
1604 struct btrfs_key key;
1605 struct btrfs_key found_key;
1606 struct extent_buffer *leaf;
1607
1608 block_group_cache = &info->block_group_cache;
1609
1610 root = info->extent_root;
1611 key.objectid = 0;
1612 key.offset = BTRFS_BLOCK_GROUP_SIZE;
1613 btrfs_set_key_type(&key, BTRFS_BLOCK_GROUP_ITEM_KEY);
1614
1615 path = btrfs_alloc_path();
1616 if (!path)
1617 return -ENOMEM;
1618
1619 while(1) {
1620 ret = btrfs_search_slot(NULL, info->extent_root,
1621 &key, path, 0, 0);
1622 if (ret != 0) {
1623 err = ret;
1624 break;
1625 }
1626 leaf = path->nodes[0];
1627 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
1628 cache = kmalloc(sizeof(*cache), GFP_NOFS);
1629 if (!cache) {
1630 err = -1;
1631 break;
1632 }
1633
1634 read_extent_buffer(leaf, &cache->item,
1635 btrfs_item_ptr_offset(leaf, path->slots[0]),
1636 sizeof(cache->item));
1637 memcpy(&cache->key, &found_key, sizeof(found_key));
1638 cache->cached = 0;
1639 cache->pinned = 0;
1640 key.objectid = found_key.objectid + found_key.offset;
1641 btrfs_release_path(root, path);
1642
1643 if (cache->item.flags & BTRFS_BLOCK_GROUP_MIXED) {
1644 bit = BLOCK_GROUP_DATA | BLOCK_GROUP_METADATA;
1645 cache->data = BTRFS_BLOCK_GROUP_MIXED;
1646 } else if (cache->item.flags & BTRFS_BLOCK_GROUP_DATA) {
1647 bit = BLOCK_GROUP_DATA;
1648 cache->data = BTRFS_BLOCK_GROUP_DATA;
1649 } else {
1650 bit = BLOCK_GROUP_METADATA;
1651 cache->data = 0;
1652 }
1653
1654 /* use EXTENT_LOCKED to prevent merging */
1655 set_extent_bits(block_group_cache, found_key.objectid,
1656 found_key.objectid + found_key.offset - 1,
1657 bit | EXTENT_LOCKED, GFP_NOFS);
1658 set_state_private(block_group_cache, found_key.objectid,
1659 (unsigned long)cache);
1660
1661 if (key.objectid >=
1662 btrfs_super_total_bytes(&info->super_copy))
1663 break;
1664 }
1665
1666 btrfs_free_path(path);
1667 return 0;
1668}
Linux 6.x block layer and io_uring tree(s)