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btrfs: don't use GFP_HIGHMEM for free-space-tree bitmap kzalloc
[linux-2.6-block.git] / fs / btrfs / free-space-tree.c
CommitLineData
a5ed9182
OS		 1/*
2 * Copyright (C) 2015 Facebook. 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/kernel.h>
20#include <linux/vmalloc.h>
21#include "ctree.h"
22#include "disk-io.h"
23#include "locking.h"
24#include "free-space-tree.h"
25#include "transaction.h"
14e46e04 26#include "sysfs.h"
a5ed9182
OS		 27
28static int __add_block_group_free_space(struct btrfs_trans_handle *trans,
29 struct btrfs_fs_info *fs_info,
30 struct btrfs_block_group_cache *block_group,
31 struct btrfs_path *path);
32
33void set_free_space_tree_thresholds(struct btrfs_block_group_cache *cache)
34{
35 u32 bitmap_range;
36 size_t bitmap_size;
37 u64 num_bitmaps, total_bitmap_size;
38
39 /*
40 * We convert to bitmaps when the disk space required for using extents
41 * exceeds that required for using bitmaps.
42 */
43 bitmap_range = cache->sectorsize * BTRFS_FREE_SPACE_BITMAP_BITS;
44 num_bitmaps = div_u64(cache->key.offset + bitmap_range - 1,
45 bitmap_range);
46 bitmap_size = sizeof(struct btrfs_item) + BTRFS_FREE_SPACE_BITMAP_SIZE;
47 total_bitmap_size = num_bitmaps * bitmap_size;
48 cache->bitmap_high_thresh = div_u64(total_bitmap_size,
49 sizeof(struct btrfs_item));
50
51 /*
52 * We allow for a small buffer between the high threshold and low
53 * threshold to avoid thrashing back and forth between the two formats.
54 */
55 if (cache->bitmap_high_thresh > 100)
56 cache->bitmap_low_thresh = cache->bitmap_high_thresh - 100;
57 else
58 cache->bitmap_low_thresh = 0;
59}
60
61static int add_new_free_space_info(struct btrfs_trans_handle *trans,
62 struct btrfs_fs_info *fs_info,
63 struct btrfs_block_group_cache *block_group,
64 struct btrfs_path *path)
65{
66 struct btrfs_root *root = fs_info->free_space_root;
67 struct btrfs_free_space_info *info;
68 struct btrfs_key key;
69 struct extent_buffer *leaf;
70 int ret;
71
72 key.objectid = block_group->key.objectid;
73 key.type = BTRFS_FREE_SPACE_INFO_KEY;
74 key.offset = block_group->key.offset;
75
76 ret = btrfs_insert_empty_item(trans, root, path, &key, sizeof(*info));
77 if (ret)
78 goto out;
79
80 leaf = path->nodes[0];
81 info = btrfs_item_ptr(leaf, path->slots[0],
82 struct btrfs_free_space_info);
83 btrfs_set_free_space_extent_count(leaf, info, 0);
84 btrfs_set_free_space_flags(leaf, info, 0);
85 btrfs_mark_buffer_dirty(leaf);
86
87 ret = 0;
88out:
89 btrfs_release_path(path);
90 return ret;
91}
92
93struct btrfs_free_space_info *
94search_free_space_info(struct btrfs_trans_handle *trans,
95 struct btrfs_fs_info *fs_info,
96 struct btrfs_block_group_cache *block_group,
97 struct btrfs_path *path, int cow)
98{
99 struct btrfs_root *root = fs_info->free_space_root;
100 struct btrfs_key key;
101 int ret;
102
103 key.objectid = block_group->key.objectid;
104 key.type = BTRFS_FREE_SPACE_INFO_KEY;
105 key.offset = block_group->key.offset;
106
107 ret = btrfs_search_slot(trans, root, &key, path, 0, cow);
108 if (ret < 0)
109 return ERR_PTR(ret);
110 if (ret != 0) {
111 btrfs_warn(fs_info, "missing free space info for %llu\n",
112 block_group->key.objectid);
113 ASSERT(0);
114 return ERR_PTR(-ENOENT);
115 }
116
117 return btrfs_item_ptr(path->nodes[0], path->slots[0],
118 struct btrfs_free_space_info);
119}
120
121/*
122 * btrfs_search_slot() but we're looking for the greatest key less than the
123 * passed key.
124 */
125static int btrfs_search_prev_slot(struct btrfs_trans_handle *trans,
126 struct btrfs_root *root,
127 struct btrfs_key *key, struct btrfs_path *p,
128 int ins_len, int cow)
129{
130 int ret;
131
132 ret = btrfs_search_slot(trans, root, key, p, ins_len, cow);
133 if (ret < 0)
134 return ret;
135
136 if (ret == 0) {
137 ASSERT(0);
138 return -EIO;
139 }
140
141 if (p->slots[0] == 0) {
142 ASSERT(0);
143 return -EIO;
144 }
145 p->slots[0]--;
146
147 return 0;
148}
149
150static inline u32 free_space_bitmap_size(u64 size, u32 sectorsize)
151{
152 return DIV_ROUND_UP((u32)div_u64(size, sectorsize), BITS_PER_BYTE);
153}
154
155static unsigned long *alloc_bitmap(u32 bitmap_size)
156{
79b134a2
DS		 157 void *mem;
158
159 /*
160 * The allocation size varies, observed numbers were < 4K up to 16K.
161 * Using vmalloc unconditionally would be too heavy, we'll try
162 * contiguous allocations first.
163 */
164 if (bitmap_size <= PAGE_SIZE)
165 return kzalloc(bitmap_size, GFP_NOFS);
166
e1c0ebad 167 mem = kzalloc(bitmap_size, GFP_NOFS | __GFP_NOWARN);
79b134a2
DS		 168 if (mem)
169 return mem;
170
a5ed9182
OS		 171 return __vmalloc(bitmap_size, GFP_NOFS | __GFP_HIGHMEM | __GFP_ZERO,
172 PAGE_KERNEL);
173}
174
175int convert_free_space_to_bitmaps(struct btrfs_trans_handle *trans,
176 struct btrfs_fs_info *fs_info,
177 struct btrfs_block_group_cache *block_group,
178 struct btrfs_path *path)
179{
180 struct btrfs_root *root = fs_info->free_space_root;
181 struct btrfs_free_space_info *info;
182 struct btrfs_key key, found_key;
183 struct extent_buffer *leaf;
184 unsigned long *bitmap;
185 char *bitmap_cursor;
186 u64 start, end;
187 u64 bitmap_range, i;
188 u32 bitmap_size, flags, expected_extent_count;
189 u32 extent_count = 0;
190 int done = 0, nr;
191 int ret;
192
193 bitmap_size = free_space_bitmap_size(block_group->key.offset,
194 block_group->sectorsize);
195 bitmap = alloc_bitmap(bitmap_size);
196 if (!bitmap) {
197 ret = -ENOMEM;
198 goto out;
199 }
200
201 start = block_group->key.objectid;
202 end = block_group->key.objectid + block_group->key.offset;
203
204 key.objectid = end - 1;
205 key.type = (u8)-1;
206 key.offset = (u64)-1;
207
208 while (!done) {
209 ret = btrfs_search_prev_slot(trans, root, &key, path, -1, 1);
210 if (ret)
211 goto out;
212
213 leaf = path->nodes[0];
214 nr = 0;
215 path->slots[0]++;
216 while (path->slots[0] > 0) {
217 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0] - 1);
218
219 if (found_key.type == BTRFS_FREE_SPACE_INFO_KEY) {
220 ASSERT(found_key.objectid == block_group->key.objectid);
221 ASSERT(found_key.offset == block_group->key.offset);
222 done = 1;
223 break;
224 } else if (found_key.type == BTRFS_FREE_SPACE_EXTENT_KEY) {
225 u64 first, last;
226
227 ASSERT(found_key.objectid >= start);
228 ASSERT(found_key.objectid < end);
229 ASSERT(found_key.objectid + found_key.offset <= end);
230
231 first = div_u64(found_key.objectid - start,
232 block_group->sectorsize);
233 last = div_u64(found_key.objectid + found_key.offset - start,
234 block_group->sectorsize);
235 bitmap_set(bitmap, first, last - first);
236
237 extent_count++;
238 nr++;
239 path->slots[0]--;
240 } else {
241 ASSERT(0);
242 }
243 }
244
245 ret = btrfs_del_items(trans, root, path, path->slots[0], nr);
246 if (ret)
247 goto out;
248 btrfs_release_path(path);
249 }
250
251 info = search_free_space_info(trans, fs_info, block_group, path, 1);
252 if (IS_ERR(info)) {
253 ret = PTR_ERR(info);
254 goto out;
255 }
256 leaf = path->nodes[0];
257 flags = btrfs_free_space_flags(leaf, info);
258 flags |= BTRFS_FREE_SPACE_USING_BITMAPS;
259 btrfs_set_free_space_flags(leaf, info, flags);
260 expected_extent_count = btrfs_free_space_extent_count(leaf, info);
261 btrfs_mark_buffer_dirty(leaf);
262 btrfs_release_path(path);
263
264 if (extent_count != expected_extent_count) {
265 btrfs_err(fs_info, "incorrect extent count for %llu; counted %u, expected %u",
266 block_group->key.objectid, extent_count,
267 expected_extent_count);
268 ASSERT(0);
269 ret = -EIO;
270 goto out;
271 }
272
273 bitmap_cursor = (char *)bitmap;
274 bitmap_range = block_group->sectorsize * BTRFS_FREE_SPACE_BITMAP_BITS;
275 i = start;
276 while (i < end) {
277 unsigned long ptr;
278 u64 extent_size;
279 u32 data_size;
280
281 extent_size = min(end - i, bitmap_range);
282 data_size = free_space_bitmap_size(extent_size,
283 block_group->sectorsize);
284
285 key.objectid = i;
286 key.type = BTRFS_FREE_SPACE_BITMAP_KEY;
287 key.offset = extent_size;
288
289 ret = btrfs_insert_empty_item(trans, root, path, &key,
290 data_size);
291 if (ret)
292 goto out;
293
294 leaf = path->nodes[0];
295 ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
296 write_extent_buffer(leaf, bitmap_cursor, ptr,
297 data_size);
298 btrfs_mark_buffer_dirty(leaf);
299 btrfs_release_path(path);
300
301 i += extent_size;
302 bitmap_cursor += data_size;
303 }
304
305 ret = 0;
306out:
79b134a2 307 kvfree(bitmap);
a5ed9182
OS		 308 if (ret)
309 btrfs_abort_transaction(trans, root, ret);
310 return ret;
311}
312
313int convert_free_space_to_extents(struct btrfs_trans_handle *trans,
314 struct btrfs_fs_info *fs_info,
315 struct btrfs_block_group_cache *block_group,
316 struct btrfs_path *path)
317{
318 struct btrfs_root *root = fs_info->free_space_root;
319 struct btrfs_free_space_info *info;
320 struct btrfs_key key, found_key;
321 struct extent_buffer *leaf;
322 unsigned long *bitmap;
323 u64 start, end;
324 /* Initialize to silence GCC. */
325 u64 extent_start = 0;
326 u64 offset;
327 u32 bitmap_size, flags, expected_extent_count;
328 int prev_bit = 0, bit, bitnr;
329 u32 extent_count = 0;
330 int done = 0, nr;
331 int ret;
332
333 bitmap_size = free_space_bitmap_size(block_group->key.offset,
334 block_group->sectorsize);
335 bitmap = alloc_bitmap(bitmap_size);
336 if (!bitmap) {
337 ret = -ENOMEM;
338 goto out;
339 }
340
341 start = block_group->key.objectid;
342 end = block_group->key.objectid + block_group->key.offset;
343
344 key.objectid = end - 1;
345 key.type = (u8)-1;
346 key.offset = (u64)-1;
347
348 while (!done) {
349 ret = btrfs_search_prev_slot(trans, root, &key, path, -1, 1);
350 if (ret)
351 goto out;
352
353 leaf = path->nodes[0];
354 nr = 0;
355 path->slots[0]++;
356 while (path->slots[0] > 0) {
357 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0] - 1);
358
359 if (found_key.type == BTRFS_FREE_SPACE_INFO_KEY) {
360 ASSERT(found_key.objectid == block_group->key.objectid);
361 ASSERT(found_key.offset == block_group->key.offset);
362 done = 1;
363 break;
364 } else if (found_key.type == BTRFS_FREE_SPACE_BITMAP_KEY) {
365 unsigned long ptr;
366 char *bitmap_cursor;
367 u32 bitmap_pos, data_size;
368
369 ASSERT(found_key.objectid >= start);
370 ASSERT(found_key.objectid < end);
371 ASSERT(found_key.objectid + found_key.offset <= end);
372
373 bitmap_pos = div_u64(found_key.objectid - start,
374 block_group->sectorsize *
375 BITS_PER_BYTE);
376 bitmap_cursor = ((char *)bitmap) + bitmap_pos;
377 data_size = free_space_bitmap_size(found_key.offset,
378 block_group->sectorsize);
379
380 ptr = btrfs_item_ptr_offset(leaf, path->slots[0] - 1);
381 read_extent_buffer(leaf, bitmap_cursor, ptr,
382 data_size);
383
384 nr++;
385 path->slots[0]--;
386 } else {
387 ASSERT(0);
388 }
389 }
390
391 ret = btrfs_del_items(trans, root, path, path->slots[0], nr);
392 if (ret)
393 goto out;
394 btrfs_release_path(path);
395 }
396
397 info = search_free_space_info(trans, fs_info, block_group, path, 1);
398 if (IS_ERR(info)) {
399 ret = PTR_ERR(info);
400 goto out;
401 }
402 leaf = path->nodes[0];
403 flags = btrfs_free_space_flags(leaf, info);
404 flags &= ~BTRFS_FREE_SPACE_USING_BITMAPS;
405 btrfs_set_free_space_flags(leaf, info, flags);
406 expected_extent_count = btrfs_free_space_extent_count(leaf, info);
407 btrfs_mark_buffer_dirty(leaf);
408 btrfs_release_path(path);
409
410 offset = start;
411 bitnr = 0;
412 while (offset < end) {
413 bit = !!test_bit(bitnr, bitmap);
414 if (prev_bit == 0 && bit == 1) {
415 extent_start = offset;
416 } else if (prev_bit == 1 && bit == 0) {
417 key.objectid = extent_start;
418 key.type = BTRFS_FREE_SPACE_EXTENT_KEY;
419 key.offset = offset - extent_start;
420
421 ret = btrfs_insert_empty_item(trans, root, path, &key, 0);
422 if (ret)
423 goto out;
424 btrfs_release_path(path);
425
426 extent_count++;
427 }
428 prev_bit = bit;
429 offset += block_group->sectorsize;
430 bitnr++;
431 }
432 if (prev_bit == 1) {
433 key.objectid = extent_start;
434 key.type = BTRFS_FREE_SPACE_EXTENT_KEY;
435 key.offset = end - extent_start;
436
437 ret = btrfs_insert_empty_item(trans, root, path, &key, 0);
438 if (ret)
439 goto out;
440 btrfs_release_path(path);
441
442 extent_count++;
443 }
444
445 if (extent_count != expected_extent_count) {
446 btrfs_err(fs_info, "incorrect extent count for %llu; counted %u, expected %u",
447 block_group->key.objectid, extent_count,
448 expected_extent_count);
449 ASSERT(0);
450 ret = -EIO;
451 goto out;
452 }
453
454 ret = 0;
455out:
79b134a2 456 kvfree(bitmap);
a5ed9182
OS		 457 if (ret)
458 btrfs_abort_transaction(trans, root, ret);
459 return ret;
460}
461
462static int update_free_space_extent_count(struct btrfs_trans_handle *trans,
463 struct btrfs_fs_info *fs_info,
464 struct btrfs_block_group_cache *block_group,
465 struct btrfs_path *path,
466 int new_extents)
467{
468 struct btrfs_free_space_info *info;
469 u32 flags;
470 u32 extent_count;
471 int ret = 0;
472
473 if (new_extents == 0)
474 return 0;
475
476 info = search_free_space_info(trans, fs_info, block_group, path, 1);
477 if (IS_ERR(info)) {
478 ret = PTR_ERR(info);
479 goto out;
480 }
481 flags = btrfs_free_space_flags(path->nodes[0], info);
482 extent_count = btrfs_free_space_extent_count(path->nodes[0], info);
483
484 extent_count += new_extents;
485 btrfs_set_free_space_extent_count(path->nodes[0], info, extent_count);
486 btrfs_mark_buffer_dirty(path->nodes[0]);
487 btrfs_release_path(path);
488
489 if (!(flags & BTRFS_FREE_SPACE_USING_BITMAPS) &&
490 extent_count > block_group->bitmap_high_thresh) {
491 ret = convert_free_space_to_bitmaps(trans, fs_info, block_group,
492 path);
493 } else if ((flags & BTRFS_FREE_SPACE_USING_BITMAPS) &&
494 extent_count < block_group->bitmap_low_thresh) {
495 ret = convert_free_space_to_extents(trans, fs_info, block_group,
496 path);
497 }
498
499out:
500 return ret;
501}
502
503int free_space_test_bit(struct btrfs_block_group_cache *block_group,
504 struct btrfs_path *path, u64 offset)
505{
506 struct extent_buffer *leaf;
507 struct btrfs_key key;
508 u64 found_start, found_end;
509 unsigned long ptr, i;
510
511 leaf = path->nodes[0];
512 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
513 ASSERT(key.type == BTRFS_FREE_SPACE_BITMAP_KEY);
514
515 found_start = key.objectid;
516 found_end = key.objectid + key.offset;
517 ASSERT(offset >= found_start && offset < found_end);
518
519 ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
520 i = div_u64(offset - found_start, block_group->sectorsize);
521 return !!extent_buffer_test_bit(leaf, ptr, i);
522}
523
524static void free_space_set_bits(struct btrfs_block_group_cache *block_group,
525 struct btrfs_path *path, u64 *start, u64 *size,
526 int bit)
527{
528 struct extent_buffer *leaf;
529 struct btrfs_key key;
530 u64 end = *start + *size;
531 u64 found_start, found_end;
532 unsigned long ptr, first, last;
533
534 leaf = path->nodes[0];
535 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
536 ASSERT(key.type == BTRFS_FREE_SPACE_BITMAP_KEY);
537
538 found_start = key.objectid;
539 found_end = key.objectid + key.offset;
540 ASSERT(*start >= found_start && *start < found_end);
541 ASSERT(end > found_start);
542
543 if (end > found_end)
544 end = found_end;
545
546 ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
547 first = div_u64(*start - found_start, block_group->sectorsize);
548 last = div_u64(end - found_start, block_group->sectorsize);
549 if (bit)
550 extent_buffer_bitmap_set(leaf, ptr, first, last - first);
551 else
552 extent_buffer_bitmap_clear(leaf, ptr, first, last - first);
553 btrfs_mark_buffer_dirty(leaf);
554
555 *size -= end - *start;
556 *start = end;
557}
558
559/*
560 * We can't use btrfs_next_item() in modify_free_space_bitmap() because
561 * btrfs_next_leaf() doesn't get the path for writing. We can forgo the fancy
562 * tree walking in btrfs_next_leaf() anyways because we know exactly what we're
563 * looking for.
564 */
565static int free_space_next_bitmap(struct btrfs_trans_handle *trans,
566 struct btrfs_root *root, struct btrfs_path *p)
567{
568 struct btrfs_key key;
569
570 if (p->slots[0] + 1 < btrfs_header_nritems(p->nodes[0])) {
571 p->slots[0]++;
572 return 0;
573 }
574
575 btrfs_item_key_to_cpu(p->nodes[0], &key, p->slots[0]);
576 btrfs_release_path(p);
577
578 key.objectid += key.offset;
579 key.type = (u8)-1;
580 key.offset = (u64)-1;
581
582 return btrfs_search_prev_slot(trans, root, &key, p, 0, 1);
583}
584
585/*
586 * If remove is 1, then we are removing free space, thus clearing bits in the
587 * bitmap. If remove is 0, then we are adding free space, thus setting bits in
588 * the bitmap.
589 */
590static int modify_free_space_bitmap(struct btrfs_trans_handle *trans,
591 struct btrfs_fs_info *fs_info,
592 struct btrfs_block_group_cache *block_group,
593 struct btrfs_path *path,
594 u64 start, u64 size, int remove)
595{
596 struct btrfs_root *root = fs_info->free_space_root;
597 struct btrfs_key key;
598 u64 end = start + size;
599 u64 cur_start, cur_size;
600 int prev_bit, next_bit;
601 int new_extents;
602 int ret;
603
604 /*
605 * Read the bit for the block immediately before the extent of space if
606 * that block is within the block group.
607 */
608 if (start > block_group->key.objectid) {
609 u64 prev_block = start - block_group->sectorsize;
610
611 key.objectid = prev_block;
612 key.type = (u8)-1;
613 key.offset = (u64)-1;
614
615 ret = btrfs_search_prev_slot(trans, root, &key, path, 0, 1);
616 if (ret)
617 goto out;
618
619 prev_bit = free_space_test_bit(block_group, path, prev_block);
620
621 /* The previous block may have been in the previous bitmap. */
622 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
623 if (start >= key.objectid + key.offset) {
624 ret = free_space_next_bitmap(trans, root, path);
625 if (ret)
626 goto out;
627 }
628 } else {
629 key.objectid = start;
630 key.type = (u8)-1;
631 key.offset = (u64)-1;
632
633 ret = btrfs_search_prev_slot(trans, root, &key, path, 0, 1);
634 if (ret)
635 goto out;
636
637 prev_bit = -1;
638 }
639
640 /*
641 * Iterate over all of the bitmaps overlapped by the extent of space,
642 * clearing/setting bits as required.
643 */
644 cur_start = start;
645 cur_size = size;
646 while (1) {
647 free_space_set_bits(block_group, path, &cur_start, &cur_size,
648 !remove);
649 if (cur_size == 0)
650 break;
651 ret = free_space_next_bitmap(trans, root, path);
652 if (ret)
653 goto out;
654 }
655
656 /*
657 * Read the bit for the block immediately after the extent of space if
658 * that block is within the block group.
659 */
660 if (end < block_group->key.objectid + block_group->key.offset) {
661 /* The next block may be in the next bitmap. */
662 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
663 if (end >= key.objectid + key.offset) {
664 ret = free_space_next_bitmap(trans, root, path);
665 if (ret)
666 goto out;
667 }
668
669 next_bit = free_space_test_bit(block_group, path, end);
670 } else {
671 next_bit = -1;
672 }
673
674 if (remove) {
675 new_extents = -1;
676 if (prev_bit == 1) {
677 /* Leftover on the left. */
678 new_extents++;
679 }
680 if (next_bit == 1) {
681 /* Leftover on the right. */
682 new_extents++;
683 }
684 } else {
685 new_extents = 1;
686 if (prev_bit == 1) {
687 /* Merging with neighbor on the left. */
688 new_extents--;
689 }
690 if (next_bit == 1) {
691 /* Merging with neighbor on the right. */
692 new_extents--;
693 }
694 }
695
696 btrfs_release_path(path);
697 ret = update_free_space_extent_count(trans, fs_info, block_group, path,
698 new_extents);
699
700out:
701 return ret;
702}
703
704static int remove_free_space_extent(struct btrfs_trans_handle *trans,
705 struct btrfs_fs_info *fs_info,
706 struct btrfs_block_group_cache *block_group,
707 struct btrfs_path *path,
708 u64 start, u64 size)
709{
710 struct btrfs_root *root = fs_info->free_space_root;
711 struct btrfs_key key;
712 u64 found_start, found_end;
713 u64 end = start + size;
714 int new_extents = -1;
715 int ret;
716
717 key.objectid = start;
718 key.type = (u8)-1;
719 key.offset = (u64)-1;
720
721 ret = btrfs_search_prev_slot(trans, root, &key, path, -1, 1);
722 if (ret)
723 goto out;
724
725 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
726
727 ASSERT(key.type == BTRFS_FREE_SPACE_EXTENT_KEY);
728
729 found_start = key.objectid;
730 found_end = key.objectid + key.offset;
731 ASSERT(start >= found_start && end <= found_end);
732
733 /*
734 * Okay, now that we've found the free space extent which contains the
735 * free space that we are removing, there are four cases:
736 *
737 * 1. We're using the whole extent: delete the key we found and
738 * decrement the free space extent count.
739 * 2. We are using part of the extent starting at the beginning: delete
740 * the key we found and insert a new key representing the leftover at
741 * the end. There is no net change in the number of extents.
742 * 3. We are using part of the extent ending at the end: delete the key
743 * we found and insert a new key representing the leftover at the
744 * beginning. There is no net change in the number of extents.
745 * 4. We are using part of the extent in the middle: delete the key we
746 * found and insert two new keys representing the leftovers on each
747 * side. Where we used to have one extent, we now have two, so increment
748 * the extent count. We may need to convert the block group to bitmaps
749 * as a result.
750 */
751
752 /* Delete the existing key (cases 1-4). */
753 ret = btrfs_del_item(trans, root, path);
754 if (ret)
755 goto out;
756
757 /* Add a key for leftovers at the beginning (cases 3 and 4). */
758 if (start > found_start) {
759 key.objectid = found_start;
760 key.type = BTRFS_FREE_SPACE_EXTENT_KEY;
761 key.offset = start - found_start;
762
763 btrfs_release_path(path);
764 ret = btrfs_insert_empty_item(trans, root, path, &key, 0);
765 if (ret)
766 goto out;
767 new_extents++;
768 }
769
770 /* Add a key for leftovers at the end (cases 2 and 4). */
771 if (end < found_end) {
772 key.objectid = end;
773 key.type = BTRFS_FREE_SPACE_EXTENT_KEY;
774 key.offset = found_end - end;
775
776 btrfs_release_path(path);
777 ret = btrfs_insert_empty_item(trans, root, path, &key, 0);
778 if (ret)
779 goto out;
780 new_extents++;
781 }
782
783 btrfs_release_path(path);
784 ret = update_free_space_extent_count(trans, fs_info, block_group, path,
785 new_extents);
786
787out:
788 return ret;
789}
790
791int __remove_from_free_space_tree(struct btrfs_trans_handle *trans,
792 struct btrfs_fs_info *fs_info,
793 struct btrfs_block_group_cache *block_group,
794 struct btrfs_path *path, u64 start, u64 size)
795{
796 struct btrfs_free_space_info *info;
797 u32 flags;
798 int ret;
799
800 if (block_group->needs_free_space) {
801 ret = __add_block_group_free_space(trans, fs_info, block_group,
802 path);
803 if (ret)
804 return ret;
805 }
806
807 info = search_free_space_info(NULL, fs_info, block_group, path, 0);
808 if (IS_ERR(info))
809 return PTR_ERR(info);
810 flags = btrfs_free_space_flags(path->nodes[0], info);
811 btrfs_release_path(path);
812
813 if (flags & BTRFS_FREE_SPACE_USING_BITMAPS) {
814 return modify_free_space_bitmap(trans, fs_info, block_group,
815 path, start, size, 1);
816 } else {
817 return remove_free_space_extent(trans, fs_info, block_group,
818 path, start, size);
819 }
820}
821
822int remove_from_free_space_tree(struct btrfs_trans_handle *trans,
823 struct btrfs_fs_info *fs_info,
824 u64 start, u64 size)
825{
826 struct btrfs_block_group_cache *block_group;
827 struct btrfs_path *path;
828 int ret;
829
830 if (!btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE))
831 return 0;
832
833 path = btrfs_alloc_path();
834 if (!path) {
835 ret = -ENOMEM;
836 goto out;
837 }
838
839 block_group = btrfs_lookup_block_group(fs_info, start);
840 if (!block_group) {
841 ASSERT(0);
842 ret = -ENOENT;
843 goto out;
844 }
845
846 mutex_lock(&block_group->free_space_lock);
847 ret = __remove_from_free_space_tree(trans, fs_info, block_group, path,
848 start, size);
849 mutex_unlock(&block_group->free_space_lock);
850
851 btrfs_put_block_group(block_group);
852out:
853 btrfs_free_path(path);
854 if (ret)
855 btrfs_abort_transaction(trans, fs_info->free_space_root, ret);
856 return ret;
857}
858
859static int add_free_space_extent(struct btrfs_trans_handle *trans,
860 struct btrfs_fs_info *fs_info,
861 struct btrfs_block_group_cache *block_group,
862 struct btrfs_path *path,
863 u64 start, u64 size)
864{
865 struct btrfs_root *root = fs_info->free_space_root;
866 struct btrfs_key key, new_key;
867 u64 found_start, found_end;
868 u64 end = start + size;
869 int new_extents = 1;
870 int ret;
871
872 /*
873 * We are adding a new extent of free space, but we need to merge
874 * extents. There are four cases here:
875 *
876 * 1. The new extent does not have any immediate neighbors to merge
877 * with: add the new key and increment the free space extent count. We
878 * may need to convert the block group to bitmaps as a result.
879 * 2. The new extent has an immediate neighbor before it: remove the
880 * previous key and insert a new key combining both of them. There is no
881 * net change in the number of extents.
882 * 3. The new extent has an immediate neighbor after it: remove the next
883 * key and insert a new key combining both of them. There is no net
884 * change in the number of extents.
885 * 4. The new extent has immediate neighbors on both sides: remove both
886 * of the keys and insert a new key combining all of them. Where we used
887 * to have two extents, we now have one, so decrement the extent count.
888 */
889
890 new_key.objectid = start;
891 new_key.type = BTRFS_FREE_SPACE_EXTENT_KEY;
892 new_key.offset = size;
893
894 /* Search for a neighbor on the left. */
895 if (start == block_group->key.objectid)
896 goto right;
897 key.objectid = start - 1;
898 key.type = (u8)-1;
899 key.offset = (u64)-1;
900
901 ret = btrfs_search_prev_slot(trans, root, &key, path, -1, 1);
902 if (ret)
903 goto out;
904
905 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
906
907 if (key.type != BTRFS_FREE_SPACE_EXTENT_KEY) {
908 ASSERT(key.type == BTRFS_FREE_SPACE_INFO_KEY);
909 btrfs_release_path(path);
910 goto right;
911 }
912
913 found_start = key.objectid;
914 found_end = key.objectid + key.offset;
915 ASSERT(found_start >= block_group->key.objectid &&
916 found_end > block_group->key.objectid);
917 ASSERT(found_start < start && found_end <= start);
918
919 /*
920 * Delete the neighbor on the left and absorb it into the new key (cases
921 * 2 and 4).
922 */
923 if (found_end == start) {
924 ret = btrfs_del_item(trans, root, path);
925 if (ret)
926 goto out;
927 new_key.objectid = found_start;
928 new_key.offset += key.offset;
929 new_extents--;
930 }
931 btrfs_release_path(path);
932
933right:
934 /* Search for a neighbor on the right. */
935 if (end == block_group->key.objectid + block_group->key.offset)
936 goto insert;
937 key.objectid = end;
938 key.type = (u8)-1;
939 key.offset = (u64)-1;
940
941 ret = btrfs_search_prev_slot(trans, root, &key, path, -1, 1);
942 if (ret)
943 goto out;
944
945 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
946
947 if (key.type != BTRFS_FREE_SPACE_EXTENT_KEY) {
948 ASSERT(key.type == BTRFS_FREE_SPACE_INFO_KEY);
949 btrfs_release_path(path);
950 goto insert;
951 }
952
953 found_start = key.objectid;
954 found_end = key.objectid + key.offset;
955 ASSERT(found_start >= block_group->key.objectid &&
956 found_end > block_group->key.objectid);
957 ASSERT((found_start < start && found_end <= start) ||
958 (found_start >= end && found_end > end));
959
960 /*
961 * Delete the neighbor on the right and absorb it into the new key
962 * (cases 3 and 4).
963 */
964 if (found_start == end) {
965 ret = btrfs_del_item(trans, root, path);
966 if (ret)
967 goto out;
968 new_key.offset += key.offset;
969 new_extents--;
970 }
971 btrfs_release_path(path);
972
973insert:
974 /* Insert the new key (cases 1-4). */
975 ret = btrfs_insert_empty_item(trans, root, path, &new_key, 0);
976 if (ret)
977 goto out;
978
979 btrfs_release_path(path);
980 ret = update_free_space_extent_count(trans, fs_info, block_group, path,
981 new_extents);
982
983out:
984 return ret;
985}
986
987int __add_to_free_space_tree(struct btrfs_trans_handle *trans,
988 struct btrfs_fs_info *fs_info,
989 struct btrfs_block_group_cache *block_group,
990 struct btrfs_path *path, u64 start, u64 size)
991{
992 struct btrfs_free_space_info *info;
993 u32 flags;
994 int ret;
995
996 if (block_group->needs_free_space) {
997 ret = __add_block_group_free_space(trans, fs_info, block_group,
998 path);
999 if (ret)
1000 return ret;
1001 }
1002
1003 info = search_free_space_info(NULL, fs_info, block_group, path, 0);
1004 if (IS_ERR(info))
1005 return PTR_ERR(info);
1006 flags = btrfs_free_space_flags(path->nodes[0], info);
1007 btrfs_release_path(path);
1008
1009 if (flags & BTRFS_FREE_SPACE_USING_BITMAPS) {
1010 return modify_free_space_bitmap(trans, fs_info, block_group,
1011 path, start, size, 0);
1012 } else {
1013 return add_free_space_extent(trans, fs_info, block_group, path,
1014 start, size);
1015 }
1016}
1017
1018int add_to_free_space_tree(struct btrfs_trans_handle *trans,
1019 struct btrfs_fs_info *fs_info,
1020 u64 start, u64 size)
1021{
1022 struct btrfs_block_group_cache *block_group;
1023 struct btrfs_path *path;
1024 int ret;
1025
1026 if (!btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE))
1027 return 0;
1028
1029 path = btrfs_alloc_path();
1030 if (!path) {
1031 ret = -ENOMEM;
1032 goto out;
1033 }
1034
1035 block_group = btrfs_lookup_block_group(fs_info, start);
1036 if (!block_group) {
1037 ASSERT(0);
1038 ret = -ENOENT;
1039 goto out;
1040 }
1041
1042 mutex_lock(&block_group->free_space_lock);
1043 ret = __add_to_free_space_tree(trans, fs_info, block_group, path, start,
1044 size);
1045 mutex_unlock(&block_group->free_space_lock);
1046
1047 btrfs_put_block_group(block_group);
1048out:
1049 btrfs_free_path(path);
1050 if (ret)
1051 btrfs_abort_transaction(trans, fs_info->free_space_root, ret);
1052 return ret;
1053}
1054
1055/*
1056 * Populate the free space tree by walking the extent tree. Operations on the
1057 * extent tree that happen as a result of writes to the free space tree will go
1058 * through the normal add/remove hooks.
1059 */
1060static int populate_free_space_tree(struct btrfs_trans_handle *trans,
1061 struct btrfs_fs_info *fs_info,
1062 struct btrfs_block_group_cache *block_group)
1063{
1064 struct btrfs_root *extent_root = fs_info->extent_root;
1065 struct btrfs_path *path, *path2;
1066 struct btrfs_key key;
1067 u64 start, end;
1068 int ret;
1069
1070 path = btrfs_alloc_path();
1071 if (!path)
1072 return -ENOMEM;
1073 path->reada = 1;
1074
1075 path2 = btrfs_alloc_path();
1076 if (!path2) {
1077 btrfs_free_path(path);
1078 return -ENOMEM;
1079 }
1080
1081 ret = add_new_free_space_info(trans, fs_info, block_group, path2);
1082 if (ret)
1083 goto out;
1084
511711af
CM		 1085 mutex_lock(&block_group->free_space_lock);
1086
a5ed9182
OS		 1087 /*
1088 * Iterate through all of the extent and metadata items in this block
1089 * group, adding the free space between them and the free space at the
1090 * end. Note that EXTENT_ITEM and METADATA_ITEM are less than
1091 * BLOCK_GROUP_ITEM, so an extent may precede the block group that it's
1092 * contained in.
1093 */
1094 key.objectid = block_group->key.objectid;
1095 key.type = BTRFS_EXTENT_ITEM_KEY;
1096 key.offset = 0;
1097
1098 ret = btrfs_search_slot_for_read(extent_root, &key, path, 1, 0);
1099 if (ret < 0)
511711af 1100 goto out_locked;
a5ed9182
OS		 1101 ASSERT(ret == 0);
1102
1103 start = block_group->key.objectid;
1104 end = block_group->key.objectid + block_group->key.offset;
1105 while (1) {
1106 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
1107
1108 if (key.type == BTRFS_EXTENT_ITEM_KEY ||
1109 key.type == BTRFS_METADATA_ITEM_KEY) {
1110 if (key.objectid >= end)
1111 break;
1112
1113 if (start < key.objectid) {
1114 ret = __add_to_free_space_tree(trans, fs_info,
1115 block_group,
1116 path2, start,
1117 key.objectid -
1118 start);
1119 if (ret)
511711af 1120 goto out_locked;
a5ed9182
OS		 1121 }
1122 start = key.objectid;
1123 if (key.type == BTRFS_METADATA_ITEM_KEY)
1124 start += fs_info->tree_root->nodesize;
1125 else
1126 start += key.offset;
1127 } else if (key.type == BTRFS_BLOCK_GROUP_ITEM_KEY) {
1128 if (key.objectid != block_group->key.objectid)
1129 break;
1130 }
1131
1132 ret = btrfs_next_item(extent_root, path);
1133 if (ret < 0)
511711af 1134 goto out_locked;
a5ed9182
OS		 1135 if (ret)
1136 break;
1137 }
1138 if (start < end) {
1139 ret = __add_to_free_space_tree(trans, fs_info, block_group,
1140 path2, start, end - start);
1141 if (ret)
511711af 1142 goto out_locked;
a5ed9182
OS		 1143 }
1144
1145 ret = 0;
511711af
CM		 1146out_locked:
1147 mutex_unlock(&block_group->free_space_lock);
a5ed9182
OS		 1148out:
1149 btrfs_free_path(path2);
1150 btrfs_free_path(path);
1151 return ret;
1152}
1153
1154int btrfs_create_free_space_tree(struct btrfs_fs_info *fs_info)
1155{
1156 struct btrfs_trans_handle *trans;
1157 struct btrfs_root *tree_root = fs_info->tree_root;
1158 struct btrfs_root *free_space_root;
1159 struct btrfs_block_group_cache *block_group;
1160 struct rb_node *node;
1161 int ret;
1162
1163 trans = btrfs_start_transaction(tree_root, 0);
1164 if (IS_ERR(trans))
1165 return PTR_ERR(trans);
1166
511711af 1167 fs_info->creating_free_space_tree = 1;
a5ed9182
OS		 1168 free_space_root = btrfs_create_tree(trans, fs_info,
1169 BTRFS_FREE_SPACE_TREE_OBJECTID);
1170 if (IS_ERR(free_space_root)) {
1171 ret = PTR_ERR(free_space_root);
1172 goto abort;
1173 }
1174 fs_info->free_space_root = free_space_root;
1175
1176 node = rb_first(&fs_info->block_group_cache_tree);
1177 while (node) {
1178 block_group = rb_entry(node, struct btrfs_block_group_cache,
1179 cache_node);
1180 ret = populate_free_space_tree(trans, fs_info, block_group);
1181 if (ret)
1182 goto abort;
1183 node = rb_next(node);
1184 }
1185
1186 btrfs_set_fs_compat_ro(fs_info, FREE_SPACE_TREE);
14e46e04
DS		 1187 btrfs_sysfs_feature_update(fs_info,
1188 BTRFS_FEATURE_COMPAT_RO_FREE_SPACE_TREE, FEAT_COMPAT_RO);
1189
511711af 1190 fs_info->creating_free_space_tree = 0;
a5ed9182
OS		 1191
1192 ret = btrfs_commit_transaction(trans, tree_root);
1193 if (ret)
1194 return ret;
1195
1196 return 0;
1197
1198abort:
511711af 1199 fs_info->creating_free_space_tree = 0;
a5ed9182
OS		 1200 btrfs_abort_transaction(trans, tree_root, ret);
1201 btrfs_end_transaction(trans, tree_root);
1202 return ret;
1203}
1204
1205static int clear_free_space_tree(struct btrfs_trans_handle *trans,
1206 struct btrfs_root *root)
1207{
1208 struct btrfs_path *path;
1209 struct btrfs_key key;
1210 int nr;
1211 int ret;
1212
1213 path = btrfs_alloc_path();
1214 if (!path)
1215 return -ENOMEM;
1216
1217 path->leave_spinning = 1;
1218
1219 key.objectid = 0;
1220 key.type = 0;
1221 key.offset = 0;
1222
1223 while (1) {
1224 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1225 if (ret < 0)
1226 goto out;
1227
1228 nr = btrfs_header_nritems(path->nodes[0]);
1229 if (!nr)
1230 break;
1231
1232 path->slots[0] = 0;
1233 ret = btrfs_del_items(trans, root, path, 0, nr);
1234 if (ret)
1235 goto out;
1236
1237 btrfs_release_path(path);
1238 }
1239
1240 ret = 0;
1241out:
1242 btrfs_free_path(path);
1243 return ret;
1244}
1245
1246int btrfs_clear_free_space_tree(struct btrfs_fs_info *fs_info)
1247{
1248 struct btrfs_trans_handle *trans;
1249 struct btrfs_root *tree_root = fs_info->tree_root;
1250 struct btrfs_root *free_space_root = fs_info->free_space_root;
1251 int ret;
1252
1253 trans = btrfs_start_transaction(tree_root, 0);
1254 if (IS_ERR(trans))
1255 return PTR_ERR(trans);
1256
1257 btrfs_clear_fs_compat_ro(fs_info, FREE_SPACE_TREE);
14e46e04
DS		 1258 btrfs_sysfs_feature_update(fs_info,
1259 BTRFS_FEATURE_COMPAT_RO_FREE_SPACE_TREE, FEAT_COMPAT_RO);
1260
a5ed9182
OS		 1261 fs_info->free_space_root = NULL;
1262
1263 ret = clear_free_space_tree(trans, free_space_root);
1264 if (ret)
1265 goto abort;
1266
1267 ret = btrfs_del_root(trans, tree_root, &free_space_root->root_key);
1268 if (ret)
1269 goto abort;
1270
1271 list_del(&free_space_root->dirty_list);
1272
1273 btrfs_tree_lock(free_space_root->node);
1274 clean_tree_block(trans, tree_root->fs_info, free_space_root->node);
1275 btrfs_tree_unlock(free_space_root->node);
1276 btrfs_free_tree_block(trans, free_space_root, free_space_root->node,
1277 0, 1);
1278
1279 free_extent_buffer(free_space_root->node);
1280 free_extent_buffer(free_space_root->commit_root);
1281 kfree(free_space_root);
1282
1283 ret = btrfs_commit_transaction(trans, tree_root);
1284 if (ret)
1285 return ret;
1286
1287 return 0;
1288
1289abort:
1290 btrfs_abort_transaction(trans, tree_root, ret);
1291 btrfs_end_transaction(trans, tree_root);
1292 return ret;
1293}
1294
1295static int __add_block_group_free_space(struct btrfs_trans_handle *trans,
1296 struct btrfs_fs_info *fs_info,
1297 struct btrfs_block_group_cache *block_group,
1298 struct btrfs_path *path)
1299{
1300 u64 start, end;
1301 int ret;
1302
1303 start = block_group->key.objectid;
1304 end = block_group->key.objectid + block_group->key.offset;
1305
1306 block_group->needs_free_space = 0;
1307
1308 ret = add_new_free_space_info(trans, fs_info, block_group, path);
1309 if (ret)
1310 return ret;
1311
1312 return __add_to_free_space_tree(trans, fs_info, block_group, path,
1313 block_group->key.objectid,
1314 block_group->key.offset);
1315}
1316
1317int add_block_group_free_space(struct btrfs_trans_handle *trans,
1318 struct btrfs_fs_info *fs_info,
1319 struct btrfs_block_group_cache *block_group)
1320{
1321 struct btrfs_path *path = NULL;
1322 int ret = 0;
1323
1324 if (!btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE))
1325 return 0;
1326
1327 mutex_lock(&block_group->free_space_lock);
1328 if (!block_group->needs_free_space)
1329 goto out;
1330
1331 path = btrfs_alloc_path();
1332 if (!path) {
1333 ret = -ENOMEM;
1334 goto out;
1335 }
1336
1337 ret = __add_block_group_free_space(trans, fs_info, block_group, path);
1338
1339out:
1340 btrfs_free_path(path);
1341 mutex_unlock(&block_group->free_space_lock);
1342 if (ret)
1343 btrfs_abort_transaction(trans, fs_info->free_space_root, ret);
1344 return ret;
1345}
1346
1347int remove_block_group_free_space(struct btrfs_trans_handle *trans,
1348 struct btrfs_fs_info *fs_info,
1349 struct btrfs_block_group_cache *block_group)
1350{
1351 struct btrfs_root *root = fs_info->free_space_root;
1352 struct btrfs_path *path;
1353 struct btrfs_key key, found_key;
1354 struct extent_buffer *leaf;
1355 u64 start, end;
1356 int done = 0, nr;
1357 int ret;
1358
1359 if (!btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE))
1360 return 0;
1361
1362 if (block_group->needs_free_space) {
1363 /* We never added this block group to the free space tree. */
1364 return 0;
1365 }
1366
1367 path = btrfs_alloc_path();
1368 if (!path) {
1369 ret = -ENOMEM;
1370 goto out;
1371 }
1372
1373 start = block_group->key.objectid;
1374 end = block_group->key.objectid + block_group->key.offset;
1375
1376 key.objectid = end - 1;
1377 key.type = (u8)-1;
1378 key.offset = (u64)-1;
1379
1380 while (!done) {
1381 ret = btrfs_search_prev_slot(trans, root, &key, path, -1, 1);
1382 if (ret)
1383 goto out;
1384
1385 leaf = path->nodes[0];
1386 nr = 0;
1387 path->slots[0]++;
1388 while (path->slots[0] > 0) {
1389 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0] - 1);
1390
1391 if (found_key.type == BTRFS_FREE_SPACE_INFO_KEY) {
1392 ASSERT(found_key.objectid == block_group->key.objectid);
1393 ASSERT(found_key.offset == block_group->key.offset);
1394 done = 1;
1395 nr++;
1396 path->slots[0]--;
1397 break;
1398 } else if (found_key.type == BTRFS_FREE_SPACE_EXTENT_KEY ||
1399 found_key.type == BTRFS_FREE_SPACE_BITMAP_KEY) {
1400 ASSERT(found_key.objectid >= start);
1401 ASSERT(found_key.objectid < end);
1402 ASSERT(found_key.objectid + found_key.offset <= end);
1403 nr++;
1404 path->slots[0]--;
1405 } else {
1406 ASSERT(0);
1407 }
1408 }
1409
1410 ret = btrfs_del_items(trans, root, path, path->slots[0], nr);
1411 if (ret)
1412 goto out;
1413 btrfs_release_path(path);
1414 }
1415
1416 ret = 0;
1417out:
1418 btrfs_free_path(path);
1419 if (ret)
1420 btrfs_abort_transaction(trans, root, ret);
1421 return ret;
1422}
1423
1424static int load_free_space_bitmaps(struct btrfs_caching_control *caching_ctl,
1425 struct btrfs_path *path,
1426 u32 expected_extent_count)
1427{
1428 struct btrfs_block_group_cache *block_group;
1429 struct btrfs_fs_info *fs_info;
1430 struct btrfs_root *root;
1431 struct btrfs_key key;
1432 int prev_bit = 0, bit;
1433 /* Initialize to silence GCC. */
1434 u64 extent_start = 0;
1435 u64 end, offset;
1436 u64 total_found = 0;
1437 u32 extent_count = 0;
1438 int ret;
1439
1440 block_group = caching_ctl->block_group;
1441 fs_info = block_group->fs_info;
1442 root = fs_info->free_space_root;
1443
1444 end = block_group->key.objectid + block_group->key.offset;
1445
1446 while (1) {
1447 ret = btrfs_next_item(root, path);
1448 if (ret < 0)
1449 goto out;
1450 if (ret)
1451 break;
1452
1453 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
1454
1455 if (key.type == BTRFS_FREE_SPACE_INFO_KEY)
1456 break;
1457
1458 ASSERT(key.type == BTRFS_FREE_SPACE_BITMAP_KEY);
1459 ASSERT(key.objectid < end && key.objectid + key.offset <= end);
1460
1461 caching_ctl->progress = key.objectid;
1462
1463 offset = key.objectid;
1464 while (offset < key.objectid + key.offset) {
1465 bit = free_space_test_bit(block_group, path, offset);
1466 if (prev_bit == 0 && bit == 1) {
1467 extent_start = offset;
1468 } else if (prev_bit == 1 && bit == 0) {
1469 total_found += add_new_free_space(block_group,
1470 fs_info,
1471 extent_start,
1472 offset);
1473 if (total_found > CACHING_CTL_WAKE_UP) {
1474 total_found = 0;
1475 wake_up(&caching_ctl->wait);
1476 }
1477 extent_count++;
1478 }
1479 prev_bit = bit;
1480 offset += block_group->sectorsize;
1481 }
1482 }
1483 if (prev_bit == 1) {
1484 total_found += add_new_free_space(block_group, fs_info,
1485 extent_start, end);
1486 extent_count++;
1487 }
1488
1489 if (extent_count != expected_extent_count) {
1490 btrfs_err(fs_info, "incorrect extent count for %llu; counted %u, expected %u",
1491 block_group->key.objectid, extent_count,
1492 expected_extent_count);
1493 ASSERT(0);
1494 ret = -EIO;
1495 goto out;
1496 }
1497
1498 caching_ctl->progress = (u64)-1;
1499
1500 ret = 0;
1501out:
1502 return ret;
1503}
1504
1505static int load_free_space_extents(struct btrfs_caching_control *caching_ctl,
1506 struct btrfs_path *path,
1507 u32 expected_extent_count)
1508{
1509 struct btrfs_block_group_cache *block_group;
1510 struct btrfs_fs_info *fs_info;
1511 struct btrfs_root *root;
1512 struct btrfs_key key;
1513 u64 end;
1514 u64 total_found = 0;
1515 u32 extent_count = 0;
1516 int ret;
1517
1518 block_group = caching_ctl->block_group;
1519 fs_info = block_group->fs_info;
1520 root = fs_info->free_space_root;
1521
1522 end = block_group->key.objectid + block_group->key.offset;
1523
1524 while (1) {
1525 ret = btrfs_next_item(root, path);
1526 if (ret < 0)
1527 goto out;
1528 if (ret)
1529 break;
1530
1531 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
1532
1533 if (key.type == BTRFS_FREE_SPACE_INFO_KEY)
1534 break;
1535
1536 ASSERT(key.type == BTRFS_FREE_SPACE_EXTENT_KEY);
1537 ASSERT(key.objectid < end && key.objectid + key.offset <= end);
1538
1539 caching_ctl->progress = key.objectid;
1540
1541 total_found += add_new_free_space(block_group, fs_info,
1542 key.objectid,
1543 key.objectid + key.offset);
1544 if (total_found > CACHING_CTL_WAKE_UP) {
1545 total_found = 0;
1546 wake_up(&caching_ctl->wait);
1547 }
1548 extent_count++;
1549 }
1550
1551 if (extent_count != expected_extent_count) {
1552 btrfs_err(fs_info, "incorrect extent count for %llu; counted %u, expected %u",
1553 block_group->key.objectid, extent_count,
1554 expected_extent_count);
1555 ASSERT(0);
1556 ret = -EIO;
1557 goto out;
1558 }
1559
1560 caching_ctl->progress = (u64)-1;
1561
1562 ret = 0;
1563out:
1564 return ret;
1565}
1566
1567int load_free_space_tree(struct btrfs_caching_control *caching_ctl)
1568{
1569 struct btrfs_block_group_cache *block_group;
1570 struct btrfs_fs_info *fs_info;
1571 struct btrfs_free_space_info *info;
1572 struct btrfs_path *path;
1573 u32 extent_count, flags;
1574 int ret;
1575
1576 block_group = caching_ctl->block_group;
1577 fs_info = block_group->fs_info;
1578
1579 path = btrfs_alloc_path();
1580 if (!path)
1581 return -ENOMEM;
1582
1583 /*
1584 * Just like caching_thread() doesn't want to deadlock on the extent
1585 * tree, we don't want to deadlock on the free space tree.
1586 */
1587 path->skip_locking = 1;
1588 path->search_commit_root = 1;
1589 path->reada = 1;
1590
1591 info = search_free_space_info(NULL, fs_info, block_group, path, 0);
1592 if (IS_ERR(info)) {
1593 ret = PTR_ERR(info);
1594 goto out;
1595 }
1596 extent_count = btrfs_free_space_extent_count(path->nodes[0], info);
1597 flags = btrfs_free_space_flags(path->nodes[0], info);
1598
1599 /*
1600 * We left path pointing to the free space info item, so now
1601 * load_free_space_foo can just iterate through the free space tree from
1602 * there.
1603 */
1604 if (flags & BTRFS_FREE_SPACE_USING_BITMAPS)
1605 ret = load_free_space_bitmaps(caching_ctl, path, extent_count);
1606 else
1607 ret = load_free_space_extents(caching_ctl, path, extent_count);
1608
1609out:
1610 btrfs_free_path(path);
1611 return ret;
1612}
Linux 6.x block layer and io_uring tree(s)