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