1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Copyright (C) 2015 Facebook. All rights reserved.
4 */
5
6 #include <linux/kernel.h>
7 #include <linux/sched/mm.h>
8 #include "ctree.h"
9 #include "disk-io.h"
10 #include "locking.h"
11 #include "free-space-tree.h"
12 #include "transaction.h"
13 #include "block-group.h"
14
15 static int __add_block_group_free_space(struct btrfs_trans_handle *trans,
16 struct btrfs_block_group *block_group,
17 struct btrfs_path *path);
18
set_free_space_tree_thresholds(struct btrfs_block_group * cache)19 void set_free_space_tree_thresholds(struct btrfs_block_group *cache)
20 {
21 u32 bitmap_range;
22 size_t bitmap_size;
23 u64 num_bitmaps, total_bitmap_size;
24
25 if (WARN_ON(cache->length == 0))
26 btrfs_warn(cache->fs_info, "block group %llu length is zero",
27 cache->start);
28
29 /*
30 * We convert to bitmaps when the disk space required for using extents
31 * exceeds that required for using bitmaps.
32 */
33 bitmap_range = cache->fs_info->sectorsize * BTRFS_FREE_SPACE_BITMAP_BITS;
34 num_bitmaps = div_u64(cache->length + bitmap_range - 1, bitmap_range);
35 bitmap_size = sizeof(struct btrfs_item) + BTRFS_FREE_SPACE_BITMAP_SIZE;
36 total_bitmap_size = num_bitmaps * bitmap_size;
37 cache->bitmap_high_thresh = div_u64(total_bitmap_size,
38 sizeof(struct btrfs_item));
39
40 /*
41 * We allow for a small buffer between the high threshold and low
42 * threshold to avoid thrashing back and forth between the two formats.
43 */
44 if (cache->bitmap_high_thresh > 100)
45 cache->bitmap_low_thresh = cache->bitmap_high_thresh - 100;
46 else
47 cache->bitmap_low_thresh = 0;
48 }
49
add_new_free_space_info(struct btrfs_trans_handle * trans,struct btrfs_block_group * block_group,struct btrfs_path * path)50 static int add_new_free_space_info(struct btrfs_trans_handle *trans,
51 struct btrfs_block_group *block_group,
52 struct btrfs_path *path)
53 {
54 struct btrfs_root *root = trans->fs_info->free_space_root;
55 struct btrfs_free_space_info *info;
56 struct btrfs_key key;
57 struct extent_buffer *leaf;
58 int ret;
59
60 key.objectid = block_group->start;
61 key.type = BTRFS_FREE_SPACE_INFO_KEY;
62 key.offset = block_group->length;
63
64 ret = btrfs_insert_empty_item(trans, root, path, &key, sizeof(*info));
65 if (ret)
66 goto out;
67
68 leaf = path->nodes[0];
69 info = btrfs_item_ptr(leaf, path->slots[0],
70 struct btrfs_free_space_info);
71 btrfs_set_free_space_extent_count(leaf, info, 0);
72 btrfs_set_free_space_flags(leaf, info, 0);
73 btrfs_mark_buffer_dirty(leaf);
74
75 ret = 0;
76 out:
77 btrfs_release_path(path);
78 return ret;
79 }
80
81 EXPORT_FOR_TESTS
search_free_space_info(struct btrfs_trans_handle * trans,struct btrfs_block_group * block_group,struct btrfs_path * path,int cow)82 struct btrfs_free_space_info *search_free_space_info(
83 struct btrfs_trans_handle *trans,
84 struct btrfs_block_group *block_group,
85 struct btrfs_path *path, int cow)
86 {
87 struct btrfs_fs_info *fs_info = block_group->fs_info;
88 struct btrfs_root *root = fs_info->free_space_root;
89 struct btrfs_key key;
90 int ret;
91
92 key.objectid = block_group->start;
93 key.type = BTRFS_FREE_SPACE_INFO_KEY;
94 key.offset = block_group->length;
95
96 ret = btrfs_search_slot(trans, root, &key, path, 0, cow);
97 if (ret < 0)
98 return ERR_PTR(ret);
99 if (ret != 0) {
100 btrfs_warn(fs_info, "missing free space info for %llu",
101 block_group->start);
102 ASSERT(0);
103 return ERR_PTR(-ENOENT);
104 }
105
106 return btrfs_item_ptr(path->nodes[0], path->slots[0],
107 struct btrfs_free_space_info);
108 }
109
110 /*
111 * btrfs_search_slot() but we're looking for the greatest key less than the
112 * passed key.
113 */
btrfs_search_prev_slot(struct btrfs_trans_handle * trans,struct btrfs_root * root,struct btrfs_key * key,struct btrfs_path * p,int ins_len,int cow)114 static int btrfs_search_prev_slot(struct btrfs_trans_handle *trans,
115 struct btrfs_root *root,
116 struct btrfs_key *key, struct btrfs_path *p,
117 int ins_len, int cow)
118 {
119 int ret;
120
121 ret = btrfs_search_slot(trans, root, key, p, ins_len, cow);
122 if (ret < 0)
123 return ret;
124
125 if (ret == 0) {
126 ASSERT(0);
127 return -EIO;
128 }
129
130 if (p->slots[0] == 0) {
131 ASSERT(0);
132 return -EIO;
133 }
134 p->slots[0]--;
135
136 return 0;
137 }
138
free_space_bitmap_size(u64 size,u32 sectorsize)139 static inline u32 free_space_bitmap_size(u64 size, u32 sectorsize)
140 {
141 return DIV_ROUND_UP((u32)div_u64(size, sectorsize), BITS_PER_BYTE);
142 }
143
alloc_bitmap(u32 bitmap_size)144 static unsigned long *alloc_bitmap(u32 bitmap_size)
145 {
146 unsigned long *ret;
147 unsigned int nofs_flag;
148 u32 bitmap_rounded_size = round_up(bitmap_size, sizeof(unsigned long));
149
150 /*
151 * GFP_NOFS doesn't work with kvmalloc(), but we really can't recurse
152 * into the filesystem as the free space bitmap can be modified in the
153 * critical section of a transaction commit.
154 *
155 * TODO: push the memalloc_nofs_{save,restore}() to the caller where we
156 * know that recursion is unsafe.
157 */
158 nofs_flag = memalloc_nofs_save();
159 ret = kvzalloc(bitmap_rounded_size, GFP_KERNEL);
160 memalloc_nofs_restore(nofs_flag);
161 return ret;
162 }
163
le_bitmap_set(unsigned long * map,unsigned int start,int len)164 static void le_bitmap_set(unsigned long *map, unsigned int start, int len)
165 {
166 u8 *p = ((u8 *)map) + BIT_BYTE(start);
167 const unsigned int size = start + len;
168 int bits_to_set = BITS_PER_BYTE - (start % BITS_PER_BYTE);
169 u8 mask_to_set = BITMAP_FIRST_BYTE_MASK(start);
170
171 while (len - bits_to_set >= 0) {
172 *p |= mask_to_set;
173 len -= bits_to_set;
174 bits_to_set = BITS_PER_BYTE;
175 mask_to_set = ~0;
176 p++;
177 }
178 if (len) {
179 mask_to_set &= BITMAP_LAST_BYTE_MASK(size);
180 *p |= mask_to_set;
181 }
182 }
183
184 EXPORT_FOR_TESTS
convert_free_space_to_bitmaps(struct btrfs_trans_handle * trans,struct btrfs_block_group * block_group,struct btrfs_path * path)185 int convert_free_space_to_bitmaps(struct btrfs_trans_handle *trans,
186 struct btrfs_block_group *block_group,
187 struct btrfs_path *path)
188 {
189 struct btrfs_fs_info *fs_info = trans->fs_info;
190 struct btrfs_root *root = fs_info->free_space_root;
191 struct btrfs_free_space_info *info;
192 struct btrfs_key key, found_key;
193 struct extent_buffer *leaf;
194 unsigned long *bitmap;
195 char *bitmap_cursor;
196 u64 start, end;
197 u64 bitmap_range, i;
198 u32 bitmap_size, flags, expected_extent_count;
199 u32 extent_count = 0;
200 int done = 0, nr;
201 int ret;
202
203 bitmap_size = free_space_bitmap_size(block_group->length,
204 fs_info->sectorsize);
205 bitmap = alloc_bitmap(bitmap_size);
206 if (!bitmap) {
207 ret = -ENOMEM;
208 goto out;
209 }
210
211 start = block_group->start;
212 end = block_group->start + block_group->length;
213
214 key.objectid = end - 1;
215 key.type = (u8)-1;
216 key.offset = (u64)-1;
217
218 while (!done) {
219 ret = btrfs_search_prev_slot(trans, root, &key, path, -1, 1);
220 if (ret)
221 goto out;
222
223 leaf = path->nodes[0];
224 nr = 0;
225 path->slots[0]++;
226 while (path->slots[0] > 0) {
227 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0] - 1);
228
229 if (found_key.type == BTRFS_FREE_SPACE_INFO_KEY) {
230 ASSERT(found_key.objectid == block_group->start);
231 ASSERT(found_key.offset == block_group->length);
232 done = 1;
233 break;
234 } else if (found_key.type == BTRFS_FREE_SPACE_EXTENT_KEY) {
235 u64 first, last;
236
237 ASSERT(found_key.objectid >= start);
238 ASSERT(found_key.objectid < end);
239 ASSERT(found_key.objectid + found_key.offset <= end);
240
241 first = div_u64(found_key.objectid - start,
242 fs_info->sectorsize);
243 last = div_u64(found_key.objectid + found_key.offset - start,
244 fs_info->sectorsize);
245 le_bitmap_set(bitmap, first, last - first);
246
247 extent_count++;
248 nr++;
249 path->slots[0]--;
250 } else {
251 ASSERT(0);
252 }
253 }
254
255 ret = btrfs_del_items(trans, root, path, path->slots[0], nr);
256 if (ret)
257 goto out;
258 btrfs_release_path(path);
259 }
260
261 info = search_free_space_info(trans, block_group, path, 1);
262 if (IS_ERR(info)) {
263 ret = PTR_ERR(info);
264 goto out;
265 }
266 leaf = path->nodes[0];
267 flags = btrfs_free_space_flags(leaf, info);
268 flags |= BTRFS_FREE_SPACE_USING_BITMAPS;
269 btrfs_set_free_space_flags(leaf, info, flags);
270 expected_extent_count = btrfs_free_space_extent_count(leaf, info);
271 btrfs_mark_buffer_dirty(leaf);
272 btrfs_release_path(path);
273
274 if (extent_count != expected_extent_count) {
275 btrfs_err(fs_info,
276 "incorrect extent count for %llu; counted %u, expected %u",
277 block_group->start, extent_count,
278 expected_extent_count);
279 ASSERT(0);
280 ret = -EIO;
281 goto out;
282 }
283
284 bitmap_cursor = (char *)bitmap;
285 bitmap_range = fs_info->sectorsize * BTRFS_FREE_SPACE_BITMAP_BITS;
286 i = start;
287 while (i < end) {
288 unsigned long ptr;
289 u64 extent_size;
290 u32 data_size;
291
292 extent_size = min(end - i, bitmap_range);
293 data_size = free_space_bitmap_size(extent_size,
294 fs_info->sectorsize);
295
296 key.objectid = i;
297 key.type = BTRFS_FREE_SPACE_BITMAP_KEY;
298 key.offset = extent_size;
299
300 ret = btrfs_insert_empty_item(trans, root, path, &key,
301 data_size);
302 if (ret)
303 goto out;
304
305 leaf = path->nodes[0];
306 ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
307 write_extent_buffer(leaf, bitmap_cursor, ptr,
308 data_size);
309 btrfs_mark_buffer_dirty(leaf);
310 btrfs_release_path(path);
311
312 i += extent_size;
313 bitmap_cursor += data_size;
314 }
315
316 ret = 0;
317 out:
318 kvfree(bitmap);
319 if (ret)
320 btrfs_abort_transaction(trans, ret);
321 return ret;
322 }
323
324 EXPORT_FOR_TESTS
convert_free_space_to_extents(struct btrfs_trans_handle * trans,struct btrfs_block_group * block_group,struct btrfs_path * path)325 int convert_free_space_to_extents(struct btrfs_trans_handle *trans,
326 struct btrfs_block_group *block_group,
327 struct btrfs_path *path)
328 {
329 struct btrfs_fs_info *fs_info = trans->fs_info;
330 struct btrfs_root *root = fs_info->free_space_root;
331 struct btrfs_free_space_info *info;
332 struct btrfs_key key, found_key;
333 struct extent_buffer *leaf;
334 unsigned long *bitmap;
335 u64 start, end;
336 u32 bitmap_size, flags, expected_extent_count;
337 unsigned long nrbits, start_bit, end_bit;
338 u32 extent_count = 0;
339 int done = 0, nr;
340 int ret;
341
342 bitmap_size = free_space_bitmap_size(block_group->length,
343 fs_info->sectorsize);
344 bitmap = alloc_bitmap(bitmap_size);
345 if (!bitmap) {
346 ret = -ENOMEM;
347 goto out;
348 }
349
350 start = block_group->start;
351 end = block_group->start + block_group->length;
352
353 key.objectid = end - 1;
354 key.type = (u8)-1;
355 key.offset = (u64)-1;
356
357 while (!done) {
358 ret = btrfs_search_prev_slot(trans, root, &key, path, -1, 1);
359 if (ret)
360 goto out;
361
362 leaf = path->nodes[0];
363 nr = 0;
364 path->slots[0]++;
365 while (path->slots[0] > 0) {
366 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0] - 1);
367
368 if (found_key.type == BTRFS_FREE_SPACE_INFO_KEY) {
369 ASSERT(found_key.objectid == block_group->start);
370 ASSERT(found_key.offset == block_group->length);
371 done = 1;
372 break;
373 } else if (found_key.type == BTRFS_FREE_SPACE_BITMAP_KEY) {
374 unsigned long ptr;
375 char *bitmap_cursor;
376 u32 bitmap_pos, data_size;
377
378 ASSERT(found_key.objectid >= start);
379 ASSERT(found_key.objectid < end);
380 ASSERT(found_key.objectid + found_key.offset <= end);
381
382 bitmap_pos = div_u64(found_key.objectid - start,
383 fs_info->sectorsize *
384 BITS_PER_BYTE);
385 bitmap_cursor = ((char *)bitmap) + bitmap_pos;
386 data_size = free_space_bitmap_size(found_key.offset,
387 fs_info->sectorsize);
388
389 ptr = btrfs_item_ptr_offset(leaf, path->slots[0] - 1);
390 read_extent_buffer(leaf, bitmap_cursor, ptr,
391 data_size);
392
393 nr++;
394 path->slots[0]--;
395 } else {
396 ASSERT(0);
397 }
398 }
399
400 ret = btrfs_del_items(trans, root, path, path->slots[0], nr);
401 if (ret)
402 goto out;
403 btrfs_release_path(path);
404 }
405
406 info = search_free_space_info(trans, block_group, path, 1);
407 if (IS_ERR(info)) {
408 ret = PTR_ERR(info);
409 goto out;
410 }
411 leaf = path->nodes[0];
412 flags = btrfs_free_space_flags(leaf, info);
413 flags &= ~BTRFS_FREE_SPACE_USING_BITMAPS;
414 btrfs_set_free_space_flags(leaf, info, flags);
415 expected_extent_count = btrfs_free_space_extent_count(leaf, info);
416 btrfs_mark_buffer_dirty(leaf);
417 btrfs_release_path(path);
418
419 nrbits = div_u64(block_group->length, block_group->fs_info->sectorsize);
420 start_bit = find_next_bit_le(bitmap, nrbits, 0);
421
422 while (start_bit < nrbits) {
423 end_bit = find_next_zero_bit_le(bitmap, nrbits, start_bit);
424 ASSERT(start_bit < end_bit);
425
426 key.objectid = start + start_bit * block_group->fs_info->sectorsize;
427 key.type = BTRFS_FREE_SPACE_EXTENT_KEY;
428 key.offset = (end_bit - start_bit) * block_group->fs_info->sectorsize;
429
430 ret = btrfs_insert_empty_item(trans, root, path, &key, 0);
431 if (ret)
432 goto out;
433 btrfs_release_path(path);
434
435 extent_count++;
436
437 start_bit = find_next_bit_le(bitmap, nrbits, end_bit);
438 }
439
440 if (extent_count != expected_extent_count) {
441 btrfs_err(fs_info,
442 "incorrect extent count for %llu; counted %u, expected %u",
443 block_group->start, extent_count,
444 expected_extent_count);
445 ASSERT(0);
446 ret = -EIO;
447 goto out;
448 }
449
450 ret = 0;
451 out:
452 kvfree(bitmap);
453 if (ret)
454 btrfs_abort_transaction(trans, ret);
455 return ret;
456 }
457
update_free_space_extent_count(struct btrfs_trans_handle * trans,struct btrfs_block_group * block_group,struct btrfs_path * path,int new_extents)458 static int update_free_space_extent_count(struct btrfs_trans_handle *trans,
459 struct btrfs_block_group *block_group,
460 struct btrfs_path *path,
461 int new_extents)
462 {
463 struct btrfs_free_space_info *info;
464 u32 flags;
465 u32 extent_count;
466 int ret = 0;
467
468 if (new_extents == 0)
469 return 0;
470
471 info = search_free_space_info(trans, block_group, path, 1);
472 if (IS_ERR(info)) {
473 ret = PTR_ERR(info);
474 goto out;
475 }
476 flags = btrfs_free_space_flags(path->nodes[0], info);
477 extent_count = btrfs_free_space_extent_count(path->nodes[0], info);
478
479 extent_count += new_extents;
480 btrfs_set_free_space_extent_count(path->nodes[0], info, extent_count);
481 btrfs_mark_buffer_dirty(path->nodes[0]);
482 btrfs_release_path(path);
483
484 if (!(flags & BTRFS_FREE_SPACE_USING_BITMAPS) &&
485 extent_count > block_group->bitmap_high_thresh) {
486 ret = convert_free_space_to_bitmaps(trans, block_group, path);
487 } else if ((flags & BTRFS_FREE_SPACE_USING_BITMAPS) &&
488 extent_count < block_group->bitmap_low_thresh) {
489 ret = convert_free_space_to_extents(trans, block_group, path);
490 }
491
492 out:
493 return ret;
494 }
495
496 EXPORT_FOR_TESTS
free_space_test_bit(struct btrfs_block_group * block_group,struct btrfs_path * path,u64 offset)497 int free_space_test_bit(struct btrfs_block_group *block_group,
498 struct btrfs_path *path, u64 offset)
499 {
500 struct extent_buffer *leaf;
501 struct btrfs_key key;
502 u64 found_start, found_end;
503 unsigned long ptr, i;
504
505 leaf = path->nodes[0];
506 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
507 ASSERT(key.type == BTRFS_FREE_SPACE_BITMAP_KEY);
508
509 found_start = key.objectid;
510 found_end = key.objectid + key.offset;
511 ASSERT(offset >= found_start && offset < found_end);
512
513 ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
514 i = div_u64(offset - found_start,
515 block_group->fs_info->sectorsize);
516 return !!extent_buffer_test_bit(leaf, ptr, i);
517 }
518
free_space_set_bits(struct btrfs_block_group * block_group,struct btrfs_path * path,u64 * start,u64 * size,int bit)519 static void free_space_set_bits(struct btrfs_block_group *block_group,
520 struct btrfs_path *path, u64 *start, u64 *size,
521 int bit)
522 {
523 struct btrfs_fs_info *fs_info = block_group->fs_info;
524 struct extent_buffer *leaf;
525 struct btrfs_key key;
526 u64 end = *start + *size;
527 u64 found_start, found_end;
528 unsigned long ptr, first, last;
529
530 leaf = path->nodes[0];
531 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
532 ASSERT(key.type == BTRFS_FREE_SPACE_BITMAP_KEY);
533
534 found_start = key.objectid;
535 found_end = key.objectid + key.offset;
536 ASSERT(*start >= found_start && *start < found_end);
537 ASSERT(end > found_start);
538
539 if (end > found_end)
540 end = found_end;
541
542 ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
543 first = div_u64(*start - found_start, fs_info->sectorsize);
544 last = div_u64(end - found_start, fs_info->sectorsize);
545 if (bit)
546 extent_buffer_bitmap_set(leaf, ptr, first, last - first);
547 else
548 extent_buffer_bitmap_clear(leaf, ptr, first, last - first);
549 btrfs_mark_buffer_dirty(leaf);
550
551 *size -= end - *start;
552 *start = end;
553 }
554
555 /*
556 * We can't use btrfs_next_item() in modify_free_space_bitmap() because
557 * btrfs_next_leaf() doesn't get the path for writing. We can forgo the fancy
558 * tree walking in btrfs_next_leaf() anyways because we know exactly what we're
559 * looking for.
560 */
free_space_next_bitmap(struct btrfs_trans_handle * trans,struct btrfs_root * root,struct btrfs_path * p)561 static int free_space_next_bitmap(struct btrfs_trans_handle *trans,
562 struct btrfs_root *root, struct btrfs_path *p)
563 {
564 struct btrfs_key key;
565
566 if (p->slots[0] + 1 < btrfs_header_nritems(p->nodes[0])) {
567 p->slots[0]++;
568 return 0;
569 }
570
571 btrfs_item_key_to_cpu(p->nodes[0], &key, p->slots[0]);
572 btrfs_release_path(p);
573
574 key.objectid += key.offset;
575 key.type = (u8)-1;
576 key.offset = (u64)-1;
577
578 return btrfs_search_prev_slot(trans, root, &key, p, 0, 1);
579 }
580
581 /*
582 * If remove is 1, then we are removing free space, thus clearing bits in the
583 * bitmap. If remove is 0, then we are adding free space, thus setting bits in
584 * the bitmap.
585 */
modify_free_space_bitmap(struct btrfs_trans_handle * trans,struct btrfs_block_group * block_group,struct btrfs_path * path,u64 start,u64 size,int remove)586 static int modify_free_space_bitmap(struct btrfs_trans_handle *trans,
587 struct btrfs_block_group *block_group,
588 struct btrfs_path *path,
589 u64 start, u64 size, int remove)
590 {
591 struct btrfs_root *root = block_group->fs_info->free_space_root;
592 struct btrfs_key key;
593 u64 end = start + size;
594 u64 cur_start, cur_size;
595 int prev_bit, next_bit;
596 int new_extents;
597 int ret;
598
599 /*
600 * Read the bit for the block immediately before the extent of space if
601 * that block is within the block group.
602 */
603 if (start > block_group->start) {
604 u64 prev_block = start - block_group->fs_info->sectorsize;
605
606 key.objectid = prev_block;
607 key.type = (u8)-1;
608 key.offset = (u64)-1;
609
610 ret = btrfs_search_prev_slot(trans, root, &key, path, 0, 1);
611 if (ret)
612 goto out;
613
614 prev_bit = free_space_test_bit(block_group, path, prev_block);
615
616 /* The previous block may have been in the previous bitmap. */
617 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
618 if (start >= key.objectid + key.offset) {
619 ret = free_space_next_bitmap(trans, root, path);
620 if (ret)
621 goto out;
622 }
623 } else {
624 key.objectid = start;
625 key.type = (u8)-1;
626 key.offset = (u64)-1;
627
628 ret = btrfs_search_prev_slot(trans, root, &key, path, 0, 1);
629 if (ret)
630 goto out;
631
632 prev_bit = -1;
633 }
634
635 /*
636 * Iterate over all of the bitmaps overlapped by the extent of space,
637 * clearing/setting bits as required.
638 */
639 cur_start = start;
640 cur_size = size;
641 while (1) {
642 free_space_set_bits(block_group, path, &cur_start, &cur_size,
643 !remove);
644 if (cur_size == 0)
645 break;
646 ret = free_space_next_bitmap(trans, root, path);
647 if (ret)
648 goto out;
649 }
650
651 /*
652 * Read the bit for the block immediately after the extent of space if
653 * that block is within the block group.
654 */
655 if (end < block_group->start + block_group->length) {
656 /* The next block may be in the next bitmap. */
657 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
658 if (end >= key.objectid + key.offset) {
659 ret = free_space_next_bitmap(trans, root, path);
660 if (ret)
661 goto out;
662 }
663
664 next_bit = free_space_test_bit(block_group, path, end);
665 } else {
666 next_bit = -1;
667 }
668
669 if (remove) {
670 new_extents = -1;
671 if (prev_bit == 1) {
672 /* Leftover on the left. */
673 new_extents++;
674 }
675 if (next_bit == 1) {
676 /* Leftover on the right. */
677 new_extents++;
678 }
679 } else {
680 new_extents = 1;
681 if (prev_bit == 1) {
682 /* Merging with neighbor on the left. */
683 new_extents--;
684 }
685 if (next_bit == 1) {
686 /* Merging with neighbor on the right. */
687 new_extents--;
688 }
689 }
690
691 btrfs_release_path(path);
692 ret = update_free_space_extent_count(trans, block_group, path,
693 new_extents);
694
695 out:
696 return ret;
697 }
698
remove_free_space_extent(struct btrfs_trans_handle * trans,struct btrfs_block_group * block_group,struct btrfs_path * path,u64 start,u64 size)699 static int remove_free_space_extent(struct btrfs_trans_handle *trans,
700 struct btrfs_block_group *block_group,
701 struct btrfs_path *path,
702 u64 start, u64 size)
703 {
704 struct btrfs_root *root = trans->fs_info->free_space_root;
705 struct btrfs_key key;
706 u64 found_start, found_end;
707 u64 end = start + size;
708 int new_extents = -1;
709 int ret;
710
711 key.objectid = start;
712 key.type = (u8)-1;
713 key.offset = (u64)-1;
714
715 ret = btrfs_search_prev_slot(trans, root, &key, path, -1, 1);
716 if (ret)
717 goto out;
718
719 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
720
721 ASSERT(key.type == BTRFS_FREE_SPACE_EXTENT_KEY);
722
723 found_start = key.objectid;
724 found_end = key.objectid + key.offset;
725 ASSERT(start >= found_start && end <= found_end);
726
727 /*
728 * Okay, now that we've found the free space extent which contains the
729 * free space that we are removing, there are four cases:
730 *
731 * 1. We're using the whole extent: delete the key we found and
732 * decrement the free space extent count.
733 * 2. We are using part of the extent starting at the beginning: delete
734 * the key we found and insert a new key representing the leftover at
735 * the end. There is no net change in the number of extents.
736 * 3. We are using part of the extent ending at the end: delete the key
737 * we found and insert a new key representing the leftover at the
738 * beginning. There is no net change in the number of extents.
739 * 4. We are using part of the extent in the middle: delete the key we
740 * found and insert two new keys representing the leftovers on each
741 * side. Where we used to have one extent, we now have two, so increment
742 * the extent count. We may need to convert the block group to bitmaps
743 * as a result.
744 */
745
746 /* Delete the existing key (cases 1-4). */
747 ret = btrfs_del_item(trans, root, path);
748 if (ret)
749 goto out;
750
751 /* Add a key for leftovers at the beginning (cases 3 and 4). */
752 if (start > found_start) {
753 key.objectid = found_start;
754 key.type = BTRFS_FREE_SPACE_EXTENT_KEY;
755 key.offset = start - found_start;
756
757 btrfs_release_path(path);
758 ret = btrfs_insert_empty_item(trans, root, path, &key, 0);
759 if (ret)
760 goto out;
761 new_extents++;
762 }
763
764 /* Add a key for leftovers at the end (cases 2 and 4). */
765 if (end < found_end) {
766 key.objectid = end;
767 key.type = BTRFS_FREE_SPACE_EXTENT_KEY;
768 key.offset = found_end - end;
769
770 btrfs_release_path(path);
771 ret = btrfs_insert_empty_item(trans, root, path, &key, 0);
772 if (ret)
773 goto out;
774 new_extents++;
775 }
776
777 btrfs_release_path(path);
778 ret = update_free_space_extent_count(trans, block_group, path,
779 new_extents);
780
781 out:
782 return ret;
783 }
784
785 EXPORT_FOR_TESTS
__remove_from_free_space_tree(struct btrfs_trans_handle * trans,struct btrfs_block_group * block_group,struct btrfs_path * path,u64 start,u64 size)786 int __remove_from_free_space_tree(struct btrfs_trans_handle *trans,
787 struct btrfs_block_group *block_group,
788 struct btrfs_path *path, u64 start, u64 size)
789 {
790 struct btrfs_free_space_info *info;
791 u32 flags;
792 int ret;
793
794 if (block_group->needs_free_space) {
795 ret = __add_block_group_free_space(trans, block_group, path);
796 if (ret)
797 return ret;
798 }
799
800 info = search_free_space_info(NULL, block_group, path, 0);
801 if (IS_ERR(info))
802 return PTR_ERR(info);
803 flags = btrfs_free_space_flags(path->nodes[0], info);
804 btrfs_release_path(path);
805
806 if (flags & BTRFS_FREE_SPACE_USING_BITMAPS) {
807 return modify_free_space_bitmap(trans, block_group, path,
808 start, size, 1);
809 } else {
810 return remove_free_space_extent(trans, block_group, path,
811 start, size);
812 }
813 }
814
remove_from_free_space_tree(struct btrfs_trans_handle * trans,u64 start,u64 size)815 int remove_from_free_space_tree(struct btrfs_trans_handle *trans,
816 u64 start, u64 size)
817 {
818 struct btrfs_block_group *block_group;
819 struct btrfs_path *path;
820 int ret;
821
822 if (!btrfs_fs_compat_ro(trans->fs_info, FREE_SPACE_TREE))
823 return 0;
824
825 path = btrfs_alloc_path();
826 if (!path) {
827 ret = -ENOMEM;
828 goto out;
829 }
830
831 block_group = btrfs_lookup_block_group(trans->fs_info, start);
832 if (!block_group) {
833 ASSERT(0);
834 ret = -ENOENT;
835 goto out;
836 }
837
838 mutex_lock(&block_group->free_space_lock);
839 ret = __remove_from_free_space_tree(trans, block_group, path, start,
840 size);
841 mutex_unlock(&block_group->free_space_lock);
842
843 btrfs_put_block_group(block_group);
844 out:
845 btrfs_free_path(path);
846 if (ret)
847 btrfs_abort_transaction(trans, ret);
848 return ret;
849 }
850
add_free_space_extent(struct btrfs_trans_handle * trans,struct btrfs_block_group * block_group,struct btrfs_path * path,u64 start,u64 size)851 static int add_free_space_extent(struct btrfs_trans_handle *trans,
852 struct btrfs_block_group *block_group,
853 struct btrfs_path *path,
854 u64 start, u64 size)
855 {
856 struct btrfs_root *root = trans->fs_info->free_space_root;
857 struct btrfs_key key, new_key;
858 u64 found_start, found_end;
859 u64 end = start + size;
860 int new_extents = 1;
861 int ret;
862
863 /*
864 * We are adding a new extent of free space, but we need to merge
865 * extents. There are four cases here:
866 *
867 * 1. The new extent does not have any immediate neighbors to merge
868 * with: add the new key and increment the free space extent count. We
869 * may need to convert the block group to bitmaps as a result.
870 * 2. The new extent has an immediate neighbor before it: remove the
871 * previous key and insert a new key combining both of them. There is no
872 * net change in the number of extents.
873 * 3. The new extent has an immediate neighbor after it: remove the next
874 * key and insert a new key combining both of them. There is no net
875 * change in the number of extents.
876 * 4. The new extent has immediate neighbors on both sides: remove both
877 * of the keys and insert a new key combining all of them. Where we used
878 * to have two extents, we now have one, so decrement the extent count.
879 */
880
881 new_key.objectid = start;
882 new_key.type = BTRFS_FREE_SPACE_EXTENT_KEY;
883 new_key.offset = size;
884
885 /* Search for a neighbor on the left. */
886 if (start == block_group->start)
887 goto right;
888 key.objectid = start - 1;
889 key.type = (u8)-1;
890 key.offset = (u64)-1;
891
892 ret = btrfs_search_prev_slot(trans, root, &key, path, -1, 1);
893 if (ret)
894 goto out;
895
896 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
897
898 if (key.type != BTRFS_FREE_SPACE_EXTENT_KEY) {
899 ASSERT(key.type == BTRFS_FREE_SPACE_INFO_KEY);
900 btrfs_release_path(path);
901 goto right;
902 }
903
904 found_start = key.objectid;
905 found_end = key.objectid + key.offset;
906 ASSERT(found_start >= block_group->start &&
907 found_end > block_group->start);
908 ASSERT(found_start < start && found_end <= start);
909
910 /*
911 * Delete the neighbor on the left and absorb it into the new key (cases
912 * 2 and 4).
913 */
914 if (found_end == start) {
915 ret = btrfs_del_item(trans, root, path);
916 if (ret)
917 goto out;
918 new_key.objectid = found_start;
919 new_key.offset += key.offset;
920 new_extents--;
921 }
922 btrfs_release_path(path);
923
924 right:
925 /* Search for a neighbor on the right. */
926 if (end == block_group->start + block_group->length)
927 goto insert;
928 key.objectid = end;
929 key.type = (u8)-1;
930 key.offset = (u64)-1;
931
932 ret = btrfs_search_prev_slot(trans, root, &key, path, -1, 1);
933 if (ret)
934 goto out;
935
936 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
937
938 if (key.type != BTRFS_FREE_SPACE_EXTENT_KEY) {
939 ASSERT(key.type == BTRFS_FREE_SPACE_INFO_KEY);
940 btrfs_release_path(path);
941 goto insert;
942 }
943
944 found_start = key.objectid;
945 found_end = key.objectid + key.offset;
946 ASSERT(found_start >= block_group->start &&
947 found_end > block_group->start);
948 ASSERT((found_start < start && found_end <= start) ||
949 (found_start >= end && found_end > end));
950
951 /*
952 * Delete the neighbor on the right and absorb it into the new key
953 * (cases 3 and 4).
954 */
955 if (found_start == end) {
956 ret = btrfs_del_item(trans, root, path);
957 if (ret)
958 goto out;
959 new_key.offset += key.offset;
960 new_extents--;
961 }
962 btrfs_release_path(path);
963
964 insert:
965 /* Insert the new key (cases 1-4). */
966 ret = btrfs_insert_empty_item(trans, root, path, &new_key, 0);
967 if (ret)
968 goto out;
969
970 btrfs_release_path(path);
971 ret = update_free_space_extent_count(trans, block_group, path,
972 new_extents);
973
974 out:
975 return ret;
976 }
977
978 EXPORT_FOR_TESTS
__add_to_free_space_tree(struct btrfs_trans_handle * trans,struct btrfs_block_group * block_group,struct btrfs_path * path,u64 start,u64 size)979 int __add_to_free_space_tree(struct btrfs_trans_handle *trans,
980 struct btrfs_block_group *block_group,
981 struct btrfs_path *path, u64 start, u64 size)
982 {
983 struct btrfs_free_space_info *info;
984 u32 flags;
985 int ret;
986
987 if (block_group->needs_free_space) {
988 ret = __add_block_group_free_space(trans, block_group, path);
989 if (ret)
990 return ret;
991 }
992
993 info = search_free_space_info(NULL, block_group, path, 0);
994 if (IS_ERR(info))
995 return PTR_ERR(info);
996 flags = btrfs_free_space_flags(path->nodes[0], info);
997 btrfs_release_path(path);
998
999 if (flags & BTRFS_FREE_SPACE_USING_BITMAPS) {
1000 return modify_free_space_bitmap(trans, block_group, path,
1001 start, size, 0);
1002 } else {
1003 return add_free_space_extent(trans, block_group, path, start,
1004 size);
1005 }
1006 }
1007
add_to_free_space_tree(struct btrfs_trans_handle * trans,u64 start,u64 size)1008 int add_to_free_space_tree(struct btrfs_trans_handle *trans,
1009 u64 start, u64 size)
1010 {
1011 struct btrfs_block_group *block_group;
1012 struct btrfs_path *path;
1013 int ret;
1014
1015 if (!btrfs_fs_compat_ro(trans->fs_info, FREE_SPACE_TREE))
1016 return 0;
1017
1018 path = btrfs_alloc_path();
1019 if (!path) {
1020 ret = -ENOMEM;
1021 goto out;
1022 }
1023
1024 block_group = btrfs_lookup_block_group(trans->fs_info, start);
1025 if (!block_group) {
1026 ASSERT(0);
1027 ret = -ENOENT;
1028 goto out;
1029 }
1030
1031 mutex_lock(&block_group->free_space_lock);
1032 ret = __add_to_free_space_tree(trans, block_group, path, start, size);
1033 mutex_unlock(&block_group->free_space_lock);
1034
1035 btrfs_put_block_group(block_group);
1036 out:
1037 btrfs_free_path(path);
1038 if (ret)
1039 btrfs_abort_transaction(trans, ret);
1040 return ret;
1041 }
1042
1043 /*
1044 * Populate the free space tree by walking the extent tree. Operations on the
1045 * extent tree that happen as a result of writes to the free space tree will go
1046 * through the normal add/remove hooks.
1047 */
populate_free_space_tree(struct btrfs_trans_handle * trans,struct btrfs_block_group * block_group)1048 static int populate_free_space_tree(struct btrfs_trans_handle *trans,
1049 struct btrfs_block_group *block_group)
1050 {
1051 struct btrfs_root *extent_root = trans->fs_info->extent_root;
1052 struct btrfs_path *path, *path2;
1053 struct btrfs_key key;
1054 u64 start, end;
1055 int ret;
1056
1057 path = btrfs_alloc_path();
1058 if (!path)
1059 return -ENOMEM;
1060 path->reada = READA_FORWARD;
1061
1062 path2 = btrfs_alloc_path();
1063 if (!path2) {
1064 btrfs_free_path(path);
1065 return -ENOMEM;
1066 }
1067
1068 ret = add_new_free_space_info(trans, block_group, path2);
1069 if (ret)
1070 goto out;
1071
1072 mutex_lock(&block_group->free_space_lock);
1073
1074 /*
1075 * Iterate through all of the extent and metadata items in this block
1076 * group, adding the free space between them and the free space at the
1077 * end. Note that EXTENT_ITEM and METADATA_ITEM are less than
1078 * BLOCK_GROUP_ITEM, so an extent may precede the block group that it's
1079 * contained in.
1080 */
1081 key.objectid = block_group->start;
1082 key.type = BTRFS_EXTENT_ITEM_KEY;
1083 key.offset = 0;
1084
1085 ret = btrfs_search_slot_for_read(extent_root, &key, path, 1, 0);
1086 if (ret < 0)
1087 goto out_locked;
1088 ASSERT(ret == 0);
1089
1090 start = block_group->start;
1091 end = block_group->start + block_group->length;
1092 while (1) {
1093 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
1094
1095 if (key.type == BTRFS_EXTENT_ITEM_KEY ||
1096 key.type == BTRFS_METADATA_ITEM_KEY) {
1097 if (key.objectid >= end)
1098 break;
1099
1100 if (start < key.objectid) {
1101 ret = __add_to_free_space_tree(trans,
1102 block_group,
1103 path2, start,
1104 key.objectid -
1105 start);
1106 if (ret)
1107 goto out_locked;
1108 }
1109 start = key.objectid;
1110 if (key.type == BTRFS_METADATA_ITEM_KEY)
1111 start += trans->fs_info->nodesize;
1112 else
1113 start += key.offset;
1114 } else if (key.type == BTRFS_BLOCK_GROUP_ITEM_KEY) {
1115 if (key.objectid != block_group->start)
1116 break;
1117 }
1118
1119 ret = btrfs_next_item(extent_root, path);
1120 if (ret < 0)
1121 goto out_locked;
1122 if (ret)
1123 break;
1124 }
1125 if (start < end) {
1126 ret = __add_to_free_space_tree(trans, block_group, path2,
1127 start, end - start);
1128 if (ret)
1129 goto out_locked;
1130 }
1131
1132 ret = 0;
1133 out_locked:
1134 mutex_unlock(&block_group->free_space_lock);
1135 out:
1136 btrfs_free_path(path2);
1137 btrfs_free_path(path);
1138 return ret;
1139 }
1140
btrfs_create_free_space_tree(struct btrfs_fs_info * fs_info)1141 int btrfs_create_free_space_tree(struct btrfs_fs_info *fs_info)
1142 {
1143 struct btrfs_trans_handle *trans;
1144 struct btrfs_root *tree_root = fs_info->tree_root;
1145 struct btrfs_root *free_space_root;
1146 struct btrfs_block_group *block_group;
1147 struct rb_node *node;
1148 int ret;
1149
1150 trans = btrfs_start_transaction(tree_root, 0);
1151 if (IS_ERR(trans))
1152 return PTR_ERR(trans);
1153
1154 set_bit(BTRFS_FS_CREATING_FREE_SPACE_TREE, &fs_info->flags);
1155 set_bit(BTRFS_FS_FREE_SPACE_TREE_UNTRUSTED, &fs_info->flags);
1156 free_space_root = btrfs_create_tree(trans,
1157 BTRFS_FREE_SPACE_TREE_OBJECTID);
1158 if (IS_ERR(free_space_root)) {
1159 ret = PTR_ERR(free_space_root);
1160 goto abort;
1161 }
1162 fs_info->free_space_root = free_space_root;
1163
1164 node = rb_first(&fs_info->block_group_cache_tree);
1165 while (node) {
1166 block_group = rb_entry(node, struct btrfs_block_group,
1167 cache_node);
1168 ret = populate_free_space_tree(trans, block_group);
1169 if (ret)
1170 goto abort;
1171 node = rb_next(node);
1172 }
1173
1174 btrfs_set_fs_compat_ro(fs_info, FREE_SPACE_TREE);
1175 btrfs_set_fs_compat_ro(fs_info, FREE_SPACE_TREE_VALID);
1176 clear_bit(BTRFS_FS_CREATING_FREE_SPACE_TREE, &fs_info->flags);
1177 ret = btrfs_commit_transaction(trans);
1178
1179 /*
1180 * Now that we've committed the transaction any reading of our commit
1181 * root will be safe, so we can cache from the free space tree now.
1182 */
1183 clear_bit(BTRFS_FS_FREE_SPACE_TREE_UNTRUSTED, &fs_info->flags);
1184 return ret;
1185
1186 abort:
1187 clear_bit(BTRFS_FS_CREATING_FREE_SPACE_TREE, &fs_info->flags);
1188 clear_bit(BTRFS_FS_FREE_SPACE_TREE_UNTRUSTED, &fs_info->flags);
1189 btrfs_abort_transaction(trans, ret);
1190 btrfs_end_transaction(trans);
1191 return ret;
1192 }
1193
clear_free_space_tree(struct btrfs_trans_handle * trans,struct btrfs_root * root)1194 static int clear_free_space_tree(struct btrfs_trans_handle *trans,
1195 struct btrfs_root *root)
1196 {
1197 struct btrfs_path *path;
1198 struct btrfs_key key;
1199 int nr;
1200 int ret;
1201
1202 path = btrfs_alloc_path();
1203 if (!path)
1204 return -ENOMEM;
1205
1206 path->leave_spinning = 1;
1207
1208 key.objectid = 0;
1209 key.type = 0;
1210 key.offset = 0;
1211
1212 while (1) {
1213 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1214 if (ret < 0)
1215 goto out;
1216
1217 nr = btrfs_header_nritems(path->nodes[0]);
1218 if (!nr)
1219 break;
1220
1221 path->slots[0] = 0;
1222 ret = btrfs_del_items(trans, root, path, 0, nr);
1223 if (ret)
1224 goto out;
1225
1226 btrfs_release_path(path);
1227 }
1228
1229 ret = 0;
1230 out:
1231 btrfs_free_path(path);
1232 return ret;
1233 }
1234
btrfs_clear_free_space_tree(struct btrfs_fs_info * fs_info)1235 int btrfs_clear_free_space_tree(struct btrfs_fs_info *fs_info)
1236 {
1237 struct btrfs_trans_handle *trans;
1238 struct btrfs_root *tree_root = fs_info->tree_root;
1239 struct btrfs_root *free_space_root = fs_info->free_space_root;
1240 int ret;
1241
1242 trans = btrfs_start_transaction(tree_root, 0);
1243 if (IS_ERR(trans))
1244 return PTR_ERR(trans);
1245
1246 btrfs_clear_fs_compat_ro(fs_info, FREE_SPACE_TREE);
1247 btrfs_clear_fs_compat_ro(fs_info, FREE_SPACE_TREE_VALID);
1248 fs_info->free_space_root = NULL;
1249
1250 ret = clear_free_space_tree(trans, free_space_root);
1251 if (ret)
1252 goto abort;
1253
1254 ret = btrfs_del_root(trans, &free_space_root->root_key);
1255 if (ret)
1256 goto abort;
1257
1258 list_del(&free_space_root->dirty_list);
1259
1260 btrfs_tree_lock(free_space_root->node);
1261 btrfs_clean_tree_block(free_space_root->node);
1262 btrfs_tree_unlock(free_space_root->node);
1263 btrfs_free_tree_block(trans, free_space_root, free_space_root->node,
1264 0, 1);
1265
1266 btrfs_put_root(free_space_root);
1267
1268 return btrfs_commit_transaction(trans);
1269
1270 abort:
1271 btrfs_abort_transaction(trans, ret);
1272 btrfs_end_transaction(trans);
1273 return ret;
1274 }
1275
__add_block_group_free_space(struct btrfs_trans_handle * trans,struct btrfs_block_group * block_group,struct btrfs_path * path)1276 static int __add_block_group_free_space(struct btrfs_trans_handle *trans,
1277 struct btrfs_block_group *block_group,
1278 struct btrfs_path *path)
1279 {
1280 int ret;
1281
1282 block_group->needs_free_space = 0;
1283
1284 ret = add_new_free_space_info(trans, block_group, path);
1285 if (ret)
1286 return ret;
1287
1288 return __add_to_free_space_tree(trans, block_group, path,
1289 block_group->start,
1290 block_group->length);
1291 }
1292
add_block_group_free_space(struct btrfs_trans_handle * trans,struct btrfs_block_group * block_group)1293 int add_block_group_free_space(struct btrfs_trans_handle *trans,
1294 struct btrfs_block_group *block_group)
1295 {
1296 struct btrfs_fs_info *fs_info = trans->fs_info;
1297 struct btrfs_path *path = NULL;
1298 int ret = 0;
1299
1300 if (!btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE))
1301 return 0;
1302
1303 mutex_lock(&block_group->free_space_lock);
1304 if (!block_group->needs_free_space)
1305 goto out;
1306
1307 path = btrfs_alloc_path();
1308 if (!path) {
1309 ret = -ENOMEM;
1310 goto out;
1311 }
1312
1313 ret = __add_block_group_free_space(trans, block_group, path);
1314
1315 out:
1316 btrfs_free_path(path);
1317 mutex_unlock(&block_group->free_space_lock);
1318 if (ret)
1319 btrfs_abort_transaction(trans, ret);
1320 return ret;
1321 }
1322
remove_block_group_free_space(struct btrfs_trans_handle * trans,struct btrfs_block_group * block_group)1323 int remove_block_group_free_space(struct btrfs_trans_handle *trans,
1324 struct btrfs_block_group *block_group)
1325 {
1326 struct btrfs_root *root = trans->fs_info->free_space_root;
1327 struct btrfs_path *path;
1328 struct btrfs_key key, found_key;
1329 struct extent_buffer *leaf;
1330 u64 start, end;
1331 int done = 0, nr;
1332 int ret;
1333
1334 if (!btrfs_fs_compat_ro(trans->fs_info, FREE_SPACE_TREE))
1335 return 0;
1336
1337 if (block_group->needs_free_space) {
1338 /* We never added this block group to the free space tree. */
1339 return 0;
1340 }
1341
1342 path = btrfs_alloc_path();
1343 if (!path) {
1344 ret = -ENOMEM;
1345 goto out;
1346 }
1347
1348 start = block_group->start;
1349 end = block_group->start + block_group->length;
1350
1351 key.objectid = end - 1;
1352 key.type = (u8)-1;
1353 key.offset = (u64)-1;
1354
1355 while (!done) {
1356 ret = btrfs_search_prev_slot(trans, root, &key, path, -1, 1);
1357 if (ret)
1358 goto out;
1359
1360 leaf = path->nodes[0];
1361 nr = 0;
1362 path->slots[0]++;
1363 while (path->slots[0] > 0) {
1364 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0] - 1);
1365
1366 if (found_key.type == BTRFS_FREE_SPACE_INFO_KEY) {
1367 ASSERT(found_key.objectid == block_group->start);
1368 ASSERT(found_key.offset == block_group->length);
1369 done = 1;
1370 nr++;
1371 path->slots[0]--;
1372 break;
1373 } else if (found_key.type == BTRFS_FREE_SPACE_EXTENT_KEY ||
1374 found_key.type == BTRFS_FREE_SPACE_BITMAP_KEY) {
1375 ASSERT(found_key.objectid >= start);
1376 ASSERT(found_key.objectid < end);
1377 ASSERT(found_key.objectid + found_key.offset <= end);
1378 nr++;
1379 path->slots[0]--;
1380 } else {
1381 ASSERT(0);
1382 }
1383 }
1384
1385 ret = btrfs_del_items(trans, root, path, path->slots[0], nr);
1386 if (ret)
1387 goto out;
1388 btrfs_release_path(path);
1389 }
1390
1391 ret = 0;
1392 out:
1393 btrfs_free_path(path);
1394 if (ret)
1395 btrfs_abort_transaction(trans, ret);
1396 return ret;
1397 }
1398
load_free_space_bitmaps(struct btrfs_caching_control * caching_ctl,struct btrfs_path * path,u32 expected_extent_count)1399 static int load_free_space_bitmaps(struct btrfs_caching_control *caching_ctl,
1400 struct btrfs_path *path,
1401 u32 expected_extent_count)
1402 {
1403 struct btrfs_block_group *block_group;
1404 struct btrfs_fs_info *fs_info;
1405 struct btrfs_root *root;
1406 struct btrfs_key key;
1407 int prev_bit = 0, bit;
1408 /* Initialize to silence GCC. */
1409 u64 extent_start = 0;
1410 u64 end, offset;
1411 u64 total_found = 0;
1412 u32 extent_count = 0;
1413 int ret;
1414
1415 block_group = caching_ctl->block_group;
1416 fs_info = block_group->fs_info;
1417 root = fs_info->free_space_root;
1418
1419 end = block_group->start + block_group->length;
1420
1421 while (1) {
1422 ret = btrfs_next_item(root, path);
1423 if (ret < 0)
1424 goto out;
1425 if (ret)
1426 break;
1427
1428 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
1429
1430 if (key.type == BTRFS_FREE_SPACE_INFO_KEY)
1431 break;
1432
1433 ASSERT(key.type == BTRFS_FREE_SPACE_BITMAP_KEY);
1434 ASSERT(key.objectid < end && key.objectid + key.offset <= end);
1435
1436 caching_ctl->progress = key.objectid;
1437
1438 offset = key.objectid;
1439 while (offset < key.objectid + key.offset) {
1440 bit = free_space_test_bit(block_group, path, offset);
1441 if (prev_bit == 0 && bit == 1) {
1442 extent_start = offset;
1443 } else if (prev_bit == 1 && bit == 0) {
1444 total_found += add_new_free_space(block_group,
1445 extent_start,
1446 offset);
1447 if (total_found > CACHING_CTL_WAKE_UP) {
1448 total_found = 0;
1449 wake_up(&caching_ctl->wait);
1450 }
1451 extent_count++;
1452 }
1453 prev_bit = bit;
1454 offset += fs_info->sectorsize;
1455 }
1456 }
1457 if (prev_bit == 1) {
1458 total_found += add_new_free_space(block_group, extent_start,
1459 end);
1460 extent_count++;
1461 }
1462
1463 if (extent_count != expected_extent_count) {
1464 btrfs_err(fs_info,
1465 "incorrect extent count for %llu; counted %u, expected %u",
1466 block_group->start, extent_count,
1467 expected_extent_count);
1468 ASSERT(0);
1469 ret = -EIO;
1470 goto out;
1471 }
1472
1473 caching_ctl->progress = (u64)-1;
1474
1475 ret = 0;
1476 out:
1477 return ret;
1478 }
1479
load_free_space_extents(struct btrfs_caching_control * caching_ctl,struct btrfs_path * path,u32 expected_extent_count)1480 static int load_free_space_extents(struct btrfs_caching_control *caching_ctl,
1481 struct btrfs_path *path,
1482 u32 expected_extent_count)
1483 {
1484 struct btrfs_block_group *block_group;
1485 struct btrfs_fs_info *fs_info;
1486 struct btrfs_root *root;
1487 struct btrfs_key key;
1488 u64 end;
1489 u64 total_found = 0;
1490 u32 extent_count = 0;
1491 int ret;
1492
1493 block_group = caching_ctl->block_group;
1494 fs_info = block_group->fs_info;
1495 root = fs_info->free_space_root;
1496
1497 end = block_group->start + block_group->length;
1498
1499 while (1) {
1500 ret = btrfs_next_item(root, path);
1501 if (ret < 0)
1502 goto out;
1503 if (ret)
1504 break;
1505
1506 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
1507
1508 if (key.type == BTRFS_FREE_SPACE_INFO_KEY)
1509 break;
1510
1511 ASSERT(key.type == BTRFS_FREE_SPACE_EXTENT_KEY);
1512 ASSERT(key.objectid < end && key.objectid + key.offset <= end);
1513
1514 caching_ctl->progress = key.objectid;
1515
1516 total_found += add_new_free_space(block_group, key.objectid,
1517 key.objectid + key.offset);
1518 if (total_found > CACHING_CTL_WAKE_UP) {
1519 total_found = 0;
1520 wake_up(&caching_ctl->wait);
1521 }
1522 extent_count++;
1523 }
1524
1525 if (extent_count != expected_extent_count) {
1526 btrfs_err(fs_info,
1527 "incorrect extent count for %llu; counted %u, expected %u",
1528 block_group->start, extent_count,
1529 expected_extent_count);
1530 ASSERT(0);
1531 ret = -EIO;
1532 goto out;
1533 }
1534
1535 caching_ctl->progress = (u64)-1;
1536
1537 ret = 0;
1538 out:
1539 return ret;
1540 }
1541
load_free_space_tree(struct btrfs_caching_control * caching_ctl)1542 int load_free_space_tree(struct btrfs_caching_control *caching_ctl)
1543 {
1544 struct btrfs_block_group *block_group;
1545 struct btrfs_free_space_info *info;
1546 struct btrfs_path *path;
1547 u32 extent_count, flags;
1548 int ret;
1549
1550 block_group = caching_ctl->block_group;
1551
1552 path = btrfs_alloc_path();
1553 if (!path)
1554 return -ENOMEM;
1555
1556 /*
1557 * Just like caching_thread() doesn't want to deadlock on the extent
1558 * tree, we don't want to deadlock on the free space tree.
1559 */
1560 path->skip_locking = 1;
1561 path->search_commit_root = 1;
1562 path->reada = READA_FORWARD;
1563
1564 info = search_free_space_info(NULL, block_group, path, 0);
1565 if (IS_ERR(info)) {
1566 ret = PTR_ERR(info);
1567 goto out;
1568 }
1569 extent_count = btrfs_free_space_extent_count(path->nodes[0], info);
1570 flags = btrfs_free_space_flags(path->nodes[0], info);
1571
1572 /*
1573 * We left path pointing to the free space info item, so now
1574 * load_free_space_foo can just iterate through the free space tree from
1575 * there.
1576 */
1577 if (flags & BTRFS_FREE_SPACE_USING_BITMAPS)
1578 ret = load_free_space_bitmaps(caching_ctl, path, extent_count);
1579 else
1580 ret = load_free_space_extents(caching_ctl, path, extent_count);
1581
1582 out:
1583 btrfs_free_path(path);
1584 return ret;
1585 }
1586