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 "messages.h"
9 #include "ctree.h"
10 #include "disk-io.h"
11 #include "locking.h"
12 #include "free-space-tree.h"
13 #include "transaction.h"
14 #include "block-group.h"
15 #include "fs.h"
16 #include "accessors.h"
17 #include "extent-tree.h"
18 #include "root-tree.h"
19
20 static int __add_block_group_free_space(struct btrfs_trans_handle *trans,
21 struct btrfs_block_group *block_group,
22 struct btrfs_path *path);
23
btrfs_free_space_root(struct btrfs_block_group * block_group)24 static struct btrfs_root *btrfs_free_space_root(
25 struct btrfs_block_group *block_group)
26 {
27 struct btrfs_key key = {
28 .objectid = BTRFS_FREE_SPACE_TREE_OBJECTID,
29 .type = BTRFS_ROOT_ITEM_KEY,
30 .offset = 0,
31 };
32
33 if (btrfs_fs_incompat(block_group->fs_info, EXTENT_TREE_V2))
34 key.offset = block_group->global_root_id;
35 return btrfs_global_root(block_group->fs_info, &key);
36 }
37
set_free_space_tree_thresholds(struct btrfs_block_group * cache)38 void set_free_space_tree_thresholds(struct btrfs_block_group *cache)
39 {
40 u32 bitmap_range;
41 size_t bitmap_size;
42 u64 num_bitmaps, total_bitmap_size;
43
44 if (WARN_ON(cache->length == 0))
45 btrfs_warn(cache->fs_info, "block group %llu length is zero",
46 cache->start);
47
48 /*
49 * We convert to bitmaps when the disk space required for using extents
50 * exceeds that required for using bitmaps.
51 */
52 bitmap_range = cache->fs_info->sectorsize * BTRFS_FREE_SPACE_BITMAP_BITS;
53 num_bitmaps = div_u64(cache->length + bitmap_range - 1, bitmap_range);
54 bitmap_size = sizeof(struct btrfs_item) + BTRFS_FREE_SPACE_BITMAP_SIZE;
55 total_bitmap_size = num_bitmaps * bitmap_size;
56 cache->bitmap_high_thresh = div_u64(total_bitmap_size,
57 sizeof(struct btrfs_item));
58
59 /*
60 * We allow for a small buffer between the high threshold and low
61 * threshold to avoid thrashing back and forth between the two formats.
62 */
63 if (cache->bitmap_high_thresh > 100)
64 cache->bitmap_low_thresh = cache->bitmap_high_thresh - 100;
65 else
66 cache->bitmap_low_thresh = 0;
67 }
68
add_new_free_space_info(struct btrfs_trans_handle * trans,struct btrfs_block_group * block_group,struct btrfs_path * path)69 static int add_new_free_space_info(struct btrfs_trans_handle *trans,
70 struct btrfs_block_group *block_group,
71 struct btrfs_path *path)
72 {
73 struct btrfs_root *root = btrfs_free_space_root(block_group);
74 struct btrfs_free_space_info *info;
75 struct btrfs_key key;
76 struct extent_buffer *leaf;
77 int ret;
78
79 key.objectid = block_group->start;
80 key.type = BTRFS_FREE_SPACE_INFO_KEY;
81 key.offset = block_group->length;
82
83 ret = btrfs_insert_empty_item(trans, root, path, &key, sizeof(*info));
84 if (ret)
85 goto out;
86
87 leaf = path->nodes[0];
88 info = btrfs_item_ptr(leaf, path->slots[0],
89 struct btrfs_free_space_info);
90 btrfs_set_free_space_extent_count(leaf, info, 0);
91 btrfs_set_free_space_flags(leaf, info, 0);
92 btrfs_mark_buffer_dirty(leaf);
93
94 ret = 0;
95 out:
96 btrfs_release_path(path);
97 return ret;
98 }
99
100 EXPORT_FOR_TESTS
search_free_space_info(struct btrfs_trans_handle * trans,struct btrfs_block_group * block_group,struct btrfs_path * path,int cow)101 struct btrfs_free_space_info *search_free_space_info(
102 struct btrfs_trans_handle *trans,
103 struct btrfs_block_group *block_group,
104 struct btrfs_path *path, int cow)
105 {
106 struct btrfs_fs_info *fs_info = block_group->fs_info;
107 struct btrfs_root *root = btrfs_free_space_root(block_group);
108 struct btrfs_key key;
109 int ret;
110
111 key.objectid = block_group->start;
112 key.type = BTRFS_FREE_SPACE_INFO_KEY;
113 key.offset = block_group->length;
114
115 ret = btrfs_search_slot(trans, root, &key, path, 0, cow);
116 if (ret < 0)
117 return ERR_PTR(ret);
118 if (ret != 0) {
119 btrfs_warn(fs_info, "missing free space info for %llu",
120 block_group->start);
121 ASSERT(0);
122 return ERR_PTR(-ENOENT);
123 }
124
125 return btrfs_item_ptr(path->nodes[0], path->slots[0],
126 struct btrfs_free_space_info);
127 }
128
129 /*
130 * btrfs_search_slot() but we're looking for the greatest key less than the
131 * passed key.
132 */
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)133 static int btrfs_search_prev_slot(struct btrfs_trans_handle *trans,
134 struct btrfs_root *root,
135 struct btrfs_key *key, struct btrfs_path *p,
136 int ins_len, int cow)
137 {
138 int ret;
139
140 ret = btrfs_search_slot(trans, root, key, p, ins_len, cow);
141 if (ret < 0)
142 return ret;
143
144 if (ret == 0) {
145 ASSERT(0);
146 return -EIO;
147 }
148
149 if (p->slots[0] == 0) {
150 ASSERT(0);
151 return -EIO;
152 }
153 p->slots[0]--;
154
155 return 0;
156 }
157
free_space_bitmap_size(const struct btrfs_fs_info * fs_info,u64 size)158 static inline u32 free_space_bitmap_size(const struct btrfs_fs_info *fs_info,
159 u64 size)
160 {
161 return DIV_ROUND_UP(size >> fs_info->sectorsize_bits, BITS_PER_BYTE);
162 }
163
alloc_bitmap(u32 bitmap_size)164 static unsigned long *alloc_bitmap(u32 bitmap_size)
165 {
166 unsigned long *ret;
167 unsigned int nofs_flag;
168 u32 bitmap_rounded_size = round_up(bitmap_size, sizeof(unsigned long));
169
170 /*
171 * GFP_NOFS doesn't work with kvmalloc(), but we really can't recurse
172 * into the filesystem as the free space bitmap can be modified in the
173 * critical section of a transaction commit.
174 *
175 * TODO: push the memalloc_nofs_{save,restore}() to the caller where we
176 * know that recursion is unsafe.
177 */
178 nofs_flag = memalloc_nofs_save();
179 ret = kvzalloc(bitmap_rounded_size, GFP_KERNEL);
180 memalloc_nofs_restore(nofs_flag);
181 return ret;
182 }
183
le_bitmap_set(unsigned long * map,unsigned int start,int len)184 static void le_bitmap_set(unsigned long *map, unsigned int start, int len)
185 {
186 u8 *p = ((u8 *)map) + BIT_BYTE(start);
187 const unsigned int size = start + len;
188 int bits_to_set = BITS_PER_BYTE - (start % BITS_PER_BYTE);
189 u8 mask_to_set = BITMAP_FIRST_BYTE_MASK(start);
190
191 while (len - bits_to_set >= 0) {
192 *p |= mask_to_set;
193 len -= bits_to_set;
194 bits_to_set = BITS_PER_BYTE;
195 mask_to_set = ~0;
196 p++;
197 }
198 if (len) {
199 mask_to_set &= BITMAP_LAST_BYTE_MASK(size);
200 *p |= mask_to_set;
201 }
202 }
203
204 EXPORT_FOR_TESTS
convert_free_space_to_bitmaps(struct btrfs_trans_handle * trans,struct btrfs_block_group * block_group,struct btrfs_path * path)205 int convert_free_space_to_bitmaps(struct btrfs_trans_handle *trans,
206 struct btrfs_block_group *block_group,
207 struct btrfs_path *path)
208 {
209 struct btrfs_fs_info *fs_info = trans->fs_info;
210 struct btrfs_root *root = btrfs_free_space_root(block_group);
211 struct btrfs_free_space_info *info;
212 struct btrfs_key key, found_key;
213 struct extent_buffer *leaf;
214 unsigned long *bitmap;
215 char *bitmap_cursor;
216 u64 start, end;
217 u64 bitmap_range, i;
218 u32 bitmap_size, flags, expected_extent_count;
219 u32 extent_count = 0;
220 int done = 0, nr;
221 int ret;
222
223 bitmap_size = free_space_bitmap_size(fs_info, block_group->length);
224 bitmap = alloc_bitmap(bitmap_size);
225 if (!bitmap) {
226 ret = -ENOMEM;
227 goto out;
228 }
229
230 start = block_group->start;
231 end = block_group->start + block_group->length;
232
233 key.objectid = end - 1;
234 key.type = (u8)-1;
235 key.offset = (u64)-1;
236
237 while (!done) {
238 ret = btrfs_search_prev_slot(trans, root, &key, path, -1, 1);
239 if (ret)
240 goto out;
241
242 leaf = path->nodes[0];
243 nr = 0;
244 path->slots[0]++;
245 while (path->slots[0] > 0) {
246 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0] - 1);
247
248 if (found_key.type == BTRFS_FREE_SPACE_INFO_KEY) {
249 ASSERT(found_key.objectid == block_group->start);
250 ASSERT(found_key.offset == block_group->length);
251 done = 1;
252 break;
253 } else if (found_key.type == BTRFS_FREE_SPACE_EXTENT_KEY) {
254 u64 first, last;
255
256 ASSERT(found_key.objectid >= start);
257 ASSERT(found_key.objectid < end);
258 ASSERT(found_key.objectid + found_key.offset <= end);
259
260 first = div_u64(found_key.objectid - start,
261 fs_info->sectorsize);
262 last = div_u64(found_key.objectid + found_key.offset - start,
263 fs_info->sectorsize);
264 le_bitmap_set(bitmap, first, last - first);
265
266 extent_count++;
267 nr++;
268 path->slots[0]--;
269 } else {
270 ASSERT(0);
271 }
272 }
273
274 ret = btrfs_del_items(trans, root, path, path->slots[0], nr);
275 if (ret)
276 goto out;
277 btrfs_release_path(path);
278 }
279
280 info = search_free_space_info(trans, block_group, path, 1);
281 if (IS_ERR(info)) {
282 ret = PTR_ERR(info);
283 goto out;
284 }
285 leaf = path->nodes[0];
286 flags = btrfs_free_space_flags(leaf, info);
287 flags |= BTRFS_FREE_SPACE_USING_BITMAPS;
288 btrfs_set_free_space_flags(leaf, info, flags);
289 expected_extent_count = btrfs_free_space_extent_count(leaf, info);
290 btrfs_mark_buffer_dirty(leaf);
291 btrfs_release_path(path);
292
293 if (extent_count != expected_extent_count) {
294 btrfs_err(fs_info,
295 "incorrect extent count for %llu; counted %u, expected %u",
296 block_group->start, extent_count,
297 expected_extent_count);
298 ASSERT(0);
299 ret = -EIO;
300 goto out;
301 }
302
303 bitmap_cursor = (char *)bitmap;
304 bitmap_range = fs_info->sectorsize * BTRFS_FREE_SPACE_BITMAP_BITS;
305 i = start;
306 while (i < end) {
307 unsigned long ptr;
308 u64 extent_size;
309 u32 data_size;
310
311 extent_size = min(end - i, bitmap_range);
312 data_size = free_space_bitmap_size(fs_info, extent_size);
313
314 key.objectid = i;
315 key.type = BTRFS_FREE_SPACE_BITMAP_KEY;
316 key.offset = extent_size;
317
318 ret = btrfs_insert_empty_item(trans, root, path, &key,
319 data_size);
320 if (ret)
321 goto out;
322
323 leaf = path->nodes[0];
324 ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
325 write_extent_buffer(leaf, bitmap_cursor, ptr,
326 data_size);
327 btrfs_mark_buffer_dirty(leaf);
328 btrfs_release_path(path);
329
330 i += extent_size;
331 bitmap_cursor += data_size;
332 }
333
334 ret = 0;
335 out:
336 kvfree(bitmap);
337 if (ret)
338 btrfs_abort_transaction(trans, ret);
339 return ret;
340 }
341
342 EXPORT_FOR_TESTS
convert_free_space_to_extents(struct btrfs_trans_handle * trans,struct btrfs_block_group * block_group,struct btrfs_path * path)343 int convert_free_space_to_extents(struct btrfs_trans_handle *trans,
344 struct btrfs_block_group *block_group,
345 struct btrfs_path *path)
346 {
347 struct btrfs_fs_info *fs_info = trans->fs_info;
348 struct btrfs_root *root = btrfs_free_space_root(block_group);
349 struct btrfs_free_space_info *info;
350 struct btrfs_key key, found_key;
351 struct extent_buffer *leaf;
352 unsigned long *bitmap;
353 u64 start, end;
354 u32 bitmap_size, flags, expected_extent_count;
355 unsigned long nrbits, start_bit, end_bit;
356 u32 extent_count = 0;
357 int done = 0, nr;
358 int ret;
359
360 bitmap_size = free_space_bitmap_size(fs_info, block_group->length);
361 bitmap = alloc_bitmap(bitmap_size);
362 if (!bitmap) {
363 ret = -ENOMEM;
364 goto out;
365 }
366
367 start = block_group->start;
368 end = block_group->start + block_group->length;
369
370 key.objectid = end - 1;
371 key.type = (u8)-1;
372 key.offset = (u64)-1;
373
374 while (!done) {
375 ret = btrfs_search_prev_slot(trans, root, &key, path, -1, 1);
376 if (ret)
377 goto out;
378
379 leaf = path->nodes[0];
380 nr = 0;
381 path->slots[0]++;
382 while (path->slots[0] > 0) {
383 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0] - 1);
384
385 if (found_key.type == BTRFS_FREE_SPACE_INFO_KEY) {
386 ASSERT(found_key.objectid == block_group->start);
387 ASSERT(found_key.offset == block_group->length);
388 done = 1;
389 break;
390 } else if (found_key.type == BTRFS_FREE_SPACE_BITMAP_KEY) {
391 unsigned long ptr;
392 char *bitmap_cursor;
393 u32 bitmap_pos, data_size;
394
395 ASSERT(found_key.objectid >= start);
396 ASSERT(found_key.objectid < end);
397 ASSERT(found_key.objectid + found_key.offset <= end);
398
399 bitmap_pos = div_u64(found_key.objectid - start,
400 fs_info->sectorsize *
401 BITS_PER_BYTE);
402 bitmap_cursor = ((char *)bitmap) + bitmap_pos;
403 data_size = free_space_bitmap_size(fs_info,
404 found_key.offset);
405
406 ptr = btrfs_item_ptr_offset(leaf, path->slots[0] - 1);
407 read_extent_buffer(leaf, bitmap_cursor, ptr,
408 data_size);
409
410 nr++;
411 path->slots[0]--;
412 } else {
413 ASSERT(0);
414 }
415 }
416
417 ret = btrfs_del_items(trans, root, path, path->slots[0], nr);
418 if (ret)
419 goto out;
420 btrfs_release_path(path);
421 }
422
423 info = search_free_space_info(trans, block_group, path, 1);
424 if (IS_ERR(info)) {
425 ret = PTR_ERR(info);
426 goto out;
427 }
428 leaf = path->nodes[0];
429 flags = btrfs_free_space_flags(leaf, info);
430 flags &= ~BTRFS_FREE_SPACE_USING_BITMAPS;
431 btrfs_set_free_space_flags(leaf, info, flags);
432 expected_extent_count = btrfs_free_space_extent_count(leaf, info);
433 btrfs_mark_buffer_dirty(leaf);
434 btrfs_release_path(path);
435
436 nrbits = block_group->length >> block_group->fs_info->sectorsize_bits;
437 start_bit = find_next_bit_le(bitmap, nrbits, 0);
438
439 while (start_bit < nrbits) {
440 end_bit = find_next_zero_bit_le(bitmap, nrbits, start_bit);
441 ASSERT(start_bit < end_bit);
442
443 key.objectid = start + start_bit * block_group->fs_info->sectorsize;
444 key.type = BTRFS_FREE_SPACE_EXTENT_KEY;
445 key.offset = (end_bit - start_bit) * block_group->fs_info->sectorsize;
446
447 ret = btrfs_insert_empty_item(trans, root, path, &key, 0);
448 if (ret)
449 goto out;
450 btrfs_release_path(path);
451
452 extent_count++;
453
454 start_bit = find_next_bit_le(bitmap, nrbits, end_bit);
455 }
456
457 if (extent_count != expected_extent_count) {
458 btrfs_err(fs_info,
459 "incorrect extent count for %llu; counted %u, expected %u",
460 block_group->start, extent_count,
461 expected_extent_count);
462 ASSERT(0);
463 ret = -EIO;
464 goto out;
465 }
466
467 ret = 0;
468 out:
469 kvfree(bitmap);
470 if (ret)
471 btrfs_abort_transaction(trans, ret);
472 return ret;
473 }
474
update_free_space_extent_count(struct btrfs_trans_handle * trans,struct btrfs_block_group * block_group,struct btrfs_path * path,int new_extents)475 static int update_free_space_extent_count(struct btrfs_trans_handle *trans,
476 struct btrfs_block_group *block_group,
477 struct btrfs_path *path,
478 int new_extents)
479 {
480 struct btrfs_free_space_info *info;
481 u32 flags;
482 u32 extent_count;
483 int ret = 0;
484
485 if (new_extents == 0)
486 return 0;
487
488 info = search_free_space_info(trans, block_group, path, 1);
489 if (IS_ERR(info)) {
490 ret = PTR_ERR(info);
491 goto out;
492 }
493 flags = btrfs_free_space_flags(path->nodes[0], info);
494 extent_count = btrfs_free_space_extent_count(path->nodes[0], info);
495
496 extent_count += new_extents;
497 btrfs_set_free_space_extent_count(path->nodes[0], info, extent_count);
498 btrfs_mark_buffer_dirty(path->nodes[0]);
499 btrfs_release_path(path);
500
501 if (!(flags & BTRFS_FREE_SPACE_USING_BITMAPS) &&
502 extent_count > block_group->bitmap_high_thresh) {
503 ret = convert_free_space_to_bitmaps(trans, block_group, path);
504 } else if ((flags & BTRFS_FREE_SPACE_USING_BITMAPS) &&
505 extent_count < block_group->bitmap_low_thresh) {
506 ret = convert_free_space_to_extents(trans, block_group, path);
507 }
508
509 out:
510 return ret;
511 }
512
513 EXPORT_FOR_TESTS
free_space_test_bit(struct btrfs_block_group * block_group,struct btrfs_path * path,u64 offset)514 int free_space_test_bit(struct btrfs_block_group *block_group,
515 struct btrfs_path *path, u64 offset)
516 {
517 struct extent_buffer *leaf;
518 struct btrfs_key key;
519 u64 found_start, found_end;
520 unsigned long ptr, i;
521
522 leaf = path->nodes[0];
523 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
524 ASSERT(key.type == BTRFS_FREE_SPACE_BITMAP_KEY);
525
526 found_start = key.objectid;
527 found_end = key.objectid + key.offset;
528 ASSERT(offset >= found_start && offset < found_end);
529
530 ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
531 i = div_u64(offset - found_start,
532 block_group->fs_info->sectorsize);
533 return !!extent_buffer_test_bit(leaf, ptr, i);
534 }
535
free_space_set_bits(struct btrfs_block_group * block_group,struct btrfs_path * path,u64 * start,u64 * size,int bit)536 static void free_space_set_bits(struct btrfs_block_group *block_group,
537 struct btrfs_path *path, u64 *start, u64 *size,
538 int bit)
539 {
540 struct btrfs_fs_info *fs_info = block_group->fs_info;
541 struct extent_buffer *leaf;
542 struct btrfs_key key;
543 u64 end = *start + *size;
544 u64 found_start, found_end;
545 unsigned long ptr, first, last;
546
547 leaf = path->nodes[0];
548 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
549 ASSERT(key.type == BTRFS_FREE_SPACE_BITMAP_KEY);
550
551 found_start = key.objectid;
552 found_end = key.objectid + key.offset;
553 ASSERT(*start >= found_start && *start < found_end);
554 ASSERT(end > found_start);
555
556 if (end > found_end)
557 end = found_end;
558
559 ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
560 first = (*start - found_start) >> fs_info->sectorsize_bits;
561 last = (end - found_start) >> fs_info->sectorsize_bits;
562 if (bit)
563 extent_buffer_bitmap_set(leaf, ptr, first, last - first);
564 else
565 extent_buffer_bitmap_clear(leaf, ptr, first, last - first);
566 btrfs_mark_buffer_dirty(leaf);
567
568 *size -= end - *start;
569 *start = end;
570 }
571
572 /*
573 * We can't use btrfs_next_item() in modify_free_space_bitmap() because
574 * btrfs_next_leaf() doesn't get the path for writing. We can forgo the fancy
575 * tree walking in btrfs_next_leaf() anyways because we know exactly what we're
576 * looking for.
577 */
free_space_next_bitmap(struct btrfs_trans_handle * trans,struct btrfs_root * root,struct btrfs_path * p)578 static int free_space_next_bitmap(struct btrfs_trans_handle *trans,
579 struct btrfs_root *root, struct btrfs_path *p)
580 {
581 struct btrfs_key key;
582
583 if (p->slots[0] + 1 < btrfs_header_nritems(p->nodes[0])) {
584 p->slots[0]++;
585 return 0;
586 }
587
588 btrfs_item_key_to_cpu(p->nodes[0], &key, p->slots[0]);
589 btrfs_release_path(p);
590
591 key.objectid += key.offset;
592 key.type = (u8)-1;
593 key.offset = (u64)-1;
594
595 return btrfs_search_prev_slot(trans, root, &key, p, 0, 1);
596 }
597
598 /*
599 * If remove is 1, then we are removing free space, thus clearing bits in the
600 * bitmap. If remove is 0, then we are adding free space, thus setting bits in
601 * the bitmap.
602 */
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)603 static int modify_free_space_bitmap(struct btrfs_trans_handle *trans,
604 struct btrfs_block_group *block_group,
605 struct btrfs_path *path,
606 u64 start, u64 size, int remove)
607 {
608 struct btrfs_root *root = btrfs_free_space_root(block_group);
609 struct btrfs_key key;
610 u64 end = start + size;
611 u64 cur_start, cur_size;
612 int prev_bit, next_bit;
613 int new_extents;
614 int ret;
615
616 /*
617 * Read the bit for the block immediately before the extent of space if
618 * that block is within the block group.
619 */
620 if (start > block_group->start) {
621 u64 prev_block = start - block_group->fs_info->sectorsize;
622
623 key.objectid = prev_block;
624 key.type = (u8)-1;
625 key.offset = (u64)-1;
626
627 ret = btrfs_search_prev_slot(trans, root, &key, path, 0, 1);
628 if (ret)
629 goto out;
630
631 prev_bit = free_space_test_bit(block_group, path, prev_block);
632
633 /* The previous block may have been in the previous bitmap. */
634 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
635 if (start >= key.objectid + key.offset) {
636 ret = free_space_next_bitmap(trans, root, path);
637 if (ret)
638 goto out;
639 }
640 } else {
641 key.objectid = start;
642 key.type = (u8)-1;
643 key.offset = (u64)-1;
644
645 ret = btrfs_search_prev_slot(trans, root, &key, path, 0, 1);
646 if (ret)
647 goto out;
648
649 prev_bit = -1;
650 }
651
652 /*
653 * Iterate over all of the bitmaps overlapped by the extent of space,
654 * clearing/setting bits as required.
655 */
656 cur_start = start;
657 cur_size = size;
658 while (1) {
659 free_space_set_bits(block_group, path, &cur_start, &cur_size,
660 !remove);
661 if (cur_size == 0)
662 break;
663 ret = free_space_next_bitmap(trans, root, path);
664 if (ret)
665 goto out;
666 }
667
668 /*
669 * Read the bit for the block immediately after the extent of space if
670 * that block is within the block group.
671 */
672 if (end < block_group->start + block_group->length) {
673 /* The next block may be in the next bitmap. */
674 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
675 if (end >= key.objectid + key.offset) {
676 ret = free_space_next_bitmap(trans, root, path);
677 if (ret)
678 goto out;
679 }
680
681 next_bit = free_space_test_bit(block_group, path, end);
682 } else {
683 next_bit = -1;
684 }
685
686 if (remove) {
687 new_extents = -1;
688 if (prev_bit == 1) {
689 /* Leftover on the left. */
690 new_extents++;
691 }
692 if (next_bit == 1) {
693 /* Leftover on the right. */
694 new_extents++;
695 }
696 } else {
697 new_extents = 1;
698 if (prev_bit == 1) {
699 /* Merging with neighbor on the left. */
700 new_extents--;
701 }
702 if (next_bit == 1) {
703 /* Merging with neighbor on the right. */
704 new_extents--;
705 }
706 }
707
708 btrfs_release_path(path);
709 ret = update_free_space_extent_count(trans, block_group, path,
710 new_extents);
711
712 out:
713 return ret;
714 }
715
remove_free_space_extent(struct btrfs_trans_handle * trans,struct btrfs_block_group * block_group,struct btrfs_path * path,u64 start,u64 size)716 static int remove_free_space_extent(struct btrfs_trans_handle *trans,
717 struct btrfs_block_group *block_group,
718 struct btrfs_path *path,
719 u64 start, u64 size)
720 {
721 struct btrfs_root *root = btrfs_free_space_root(block_group);
722 struct btrfs_key key;
723 u64 found_start, found_end;
724 u64 end = start + size;
725 int new_extents = -1;
726 int ret;
727
728 key.objectid = start;
729 key.type = (u8)-1;
730 key.offset = (u64)-1;
731
732 ret = btrfs_search_prev_slot(trans, root, &key, path, -1, 1);
733 if (ret)
734 goto out;
735
736 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
737
738 ASSERT(key.type == BTRFS_FREE_SPACE_EXTENT_KEY);
739
740 found_start = key.objectid;
741 found_end = key.objectid + key.offset;
742 ASSERT(start >= found_start && end <= found_end);
743
744 /*
745 * Okay, now that we've found the free space extent which contains the
746 * free space that we are removing, there are four cases:
747 *
748 * 1. We're using the whole extent: delete the key we found and
749 * decrement the free space extent count.
750 * 2. We are using part of the extent starting at the beginning: delete
751 * the key we found and insert a new key representing the leftover at
752 * the end. There is no net change in the number of extents.
753 * 3. We are using part of the extent ending at the end: delete the key
754 * we found and insert a new key representing the leftover at the
755 * beginning. There is no net change in the number of extents.
756 * 4. We are using part of the extent in the middle: delete the key we
757 * found and insert two new keys representing the leftovers on each
758 * side. Where we used to have one extent, we now have two, so increment
759 * the extent count. We may need to convert the block group to bitmaps
760 * as a result.
761 */
762
763 /* Delete the existing key (cases 1-4). */
764 ret = btrfs_del_item(trans, root, path);
765 if (ret)
766 goto out;
767
768 /* Add a key for leftovers at the beginning (cases 3 and 4). */
769 if (start > found_start) {
770 key.objectid = found_start;
771 key.type = BTRFS_FREE_SPACE_EXTENT_KEY;
772 key.offset = start - found_start;
773
774 btrfs_release_path(path);
775 ret = btrfs_insert_empty_item(trans, root, path, &key, 0);
776 if (ret)
777 goto out;
778 new_extents++;
779 }
780
781 /* Add a key for leftovers at the end (cases 2 and 4). */
782 if (end < found_end) {
783 key.objectid = end;
784 key.type = BTRFS_FREE_SPACE_EXTENT_KEY;
785 key.offset = found_end - end;
786
787 btrfs_release_path(path);
788 ret = btrfs_insert_empty_item(trans, root, path, &key, 0);
789 if (ret)
790 goto out;
791 new_extents++;
792 }
793
794 btrfs_release_path(path);
795 ret = update_free_space_extent_count(trans, block_group, path,
796 new_extents);
797
798 out:
799 return ret;
800 }
801
802 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)803 int __remove_from_free_space_tree(struct btrfs_trans_handle *trans,
804 struct btrfs_block_group *block_group,
805 struct btrfs_path *path, u64 start, u64 size)
806 {
807 struct btrfs_free_space_info *info;
808 u32 flags;
809 int ret;
810
811 if (test_bit(BLOCK_GROUP_FLAG_NEEDS_FREE_SPACE, &block_group->runtime_flags)) {
812 ret = __add_block_group_free_space(trans, block_group, path);
813 if (ret)
814 return ret;
815 }
816
817 info = search_free_space_info(NULL, block_group, path, 0);
818 if (IS_ERR(info))
819 return PTR_ERR(info);
820 flags = btrfs_free_space_flags(path->nodes[0], info);
821 btrfs_release_path(path);
822
823 if (flags & BTRFS_FREE_SPACE_USING_BITMAPS) {
824 return modify_free_space_bitmap(trans, block_group, path,
825 start, size, 1);
826 } else {
827 return remove_free_space_extent(trans, block_group, path,
828 start, size);
829 }
830 }
831
remove_from_free_space_tree(struct btrfs_trans_handle * trans,u64 start,u64 size)832 int remove_from_free_space_tree(struct btrfs_trans_handle *trans,
833 u64 start, u64 size)
834 {
835 struct btrfs_block_group *block_group;
836 struct btrfs_path *path;
837 int ret;
838
839 if (!btrfs_fs_compat_ro(trans->fs_info, FREE_SPACE_TREE))
840 return 0;
841
842 path = btrfs_alloc_path();
843 if (!path) {
844 ret = -ENOMEM;
845 goto out;
846 }
847
848 block_group = btrfs_lookup_block_group(trans->fs_info, start);
849 if (!block_group) {
850 ASSERT(0);
851 ret = -ENOENT;
852 goto out;
853 }
854
855 mutex_lock(&block_group->free_space_lock);
856 ret = __remove_from_free_space_tree(trans, block_group, path, start,
857 size);
858 mutex_unlock(&block_group->free_space_lock);
859
860 btrfs_put_block_group(block_group);
861 out:
862 btrfs_free_path(path);
863 if (ret)
864 btrfs_abort_transaction(trans, ret);
865 return ret;
866 }
867
add_free_space_extent(struct btrfs_trans_handle * trans,struct btrfs_block_group * block_group,struct btrfs_path * path,u64 start,u64 size)868 static int add_free_space_extent(struct btrfs_trans_handle *trans,
869 struct btrfs_block_group *block_group,
870 struct btrfs_path *path,
871 u64 start, u64 size)
872 {
873 struct btrfs_root *root = btrfs_free_space_root(block_group);
874 struct btrfs_key key, new_key;
875 u64 found_start, found_end;
876 u64 end = start + size;
877 int new_extents = 1;
878 int ret;
879
880 /*
881 * We are adding a new extent of free space, but we need to merge
882 * extents. There are four cases here:
883 *
884 * 1. The new extent does not have any immediate neighbors to merge
885 * with: add the new key and increment the free space extent count. We
886 * may need to convert the block group to bitmaps as a result.
887 * 2. The new extent has an immediate neighbor before it: remove the
888 * previous key and insert a new key combining both of them. There is no
889 * net change in the number of extents.
890 * 3. The new extent has an immediate neighbor after it: remove the next
891 * key and insert a new key combining both of them. There is no net
892 * change in the number of extents.
893 * 4. The new extent has immediate neighbors on both sides: remove both
894 * of the keys and insert a new key combining all of them. Where we used
895 * to have two extents, we now have one, so decrement the extent count.
896 */
897
898 new_key.objectid = start;
899 new_key.type = BTRFS_FREE_SPACE_EXTENT_KEY;
900 new_key.offset = size;
901
902 /* Search for a neighbor on the left. */
903 if (start == block_group->start)
904 goto right;
905 key.objectid = start - 1;
906 key.type = (u8)-1;
907 key.offset = (u64)-1;
908
909 ret = btrfs_search_prev_slot(trans, root, &key, path, -1, 1);
910 if (ret)
911 goto out;
912
913 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
914
915 if (key.type != BTRFS_FREE_SPACE_EXTENT_KEY) {
916 ASSERT(key.type == BTRFS_FREE_SPACE_INFO_KEY);
917 btrfs_release_path(path);
918 goto right;
919 }
920
921 found_start = key.objectid;
922 found_end = key.objectid + key.offset;
923 ASSERT(found_start >= block_group->start &&
924 found_end > block_group->start);
925 ASSERT(found_start < start && found_end <= start);
926
927 /*
928 * Delete the neighbor on the left and absorb it into the new key (cases
929 * 2 and 4).
930 */
931 if (found_end == start) {
932 ret = btrfs_del_item(trans, root, path);
933 if (ret)
934 goto out;
935 new_key.objectid = found_start;
936 new_key.offset += key.offset;
937 new_extents--;
938 }
939 btrfs_release_path(path);
940
941 right:
942 /* Search for a neighbor on the right. */
943 if (end == block_group->start + block_group->length)
944 goto insert;
945 key.objectid = end;
946 key.type = (u8)-1;
947 key.offset = (u64)-1;
948
949 ret = btrfs_search_prev_slot(trans, root, &key, path, -1, 1);
950 if (ret)
951 goto out;
952
953 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
954
955 if (key.type != BTRFS_FREE_SPACE_EXTENT_KEY) {
956 ASSERT(key.type == BTRFS_FREE_SPACE_INFO_KEY);
957 btrfs_release_path(path);
958 goto insert;
959 }
960
961 found_start = key.objectid;
962 found_end = key.objectid + key.offset;
963 ASSERT(found_start >= block_group->start &&
964 found_end > block_group->start);
965 ASSERT((found_start < start && found_end <= start) ||
966 (found_start >= end && found_end > end));
967
968 /*
969 * Delete the neighbor on the right and absorb it into the new key
970 * (cases 3 and 4).
971 */
972 if (found_start == end) {
973 ret = btrfs_del_item(trans, root, path);
974 if (ret)
975 goto out;
976 new_key.offset += key.offset;
977 new_extents--;
978 }
979 btrfs_release_path(path);
980
981 insert:
982 /* Insert the new key (cases 1-4). */
983 ret = btrfs_insert_empty_item(trans, root, path, &new_key, 0);
984 if (ret)
985 goto out;
986
987 btrfs_release_path(path);
988 ret = update_free_space_extent_count(trans, block_group, path,
989 new_extents);
990
991 out:
992 return ret;
993 }
994
995 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)996 int __add_to_free_space_tree(struct btrfs_trans_handle *trans,
997 struct btrfs_block_group *block_group,
998 struct btrfs_path *path, u64 start, u64 size)
999 {
1000 struct btrfs_free_space_info *info;
1001 u32 flags;
1002 int ret;
1003
1004 if (test_bit(BLOCK_GROUP_FLAG_NEEDS_FREE_SPACE, &block_group->runtime_flags)) {
1005 ret = __add_block_group_free_space(trans, block_group, path);
1006 if (ret)
1007 return ret;
1008 }
1009
1010 info = search_free_space_info(NULL, block_group, path, 0);
1011 if (IS_ERR(info))
1012 return PTR_ERR(info);
1013 flags = btrfs_free_space_flags(path->nodes[0], info);
1014 btrfs_release_path(path);
1015
1016 if (flags & BTRFS_FREE_SPACE_USING_BITMAPS) {
1017 return modify_free_space_bitmap(trans, block_group, path,
1018 start, size, 0);
1019 } else {
1020 return add_free_space_extent(trans, block_group, path, start,
1021 size);
1022 }
1023 }
1024
add_to_free_space_tree(struct btrfs_trans_handle * trans,u64 start,u64 size)1025 int add_to_free_space_tree(struct btrfs_trans_handle *trans,
1026 u64 start, u64 size)
1027 {
1028 struct btrfs_block_group *block_group;
1029 struct btrfs_path *path;
1030 int ret;
1031
1032 if (!btrfs_fs_compat_ro(trans->fs_info, FREE_SPACE_TREE))
1033 return 0;
1034
1035 path = btrfs_alloc_path();
1036 if (!path) {
1037 ret = -ENOMEM;
1038 goto out;
1039 }
1040
1041 block_group = btrfs_lookup_block_group(trans->fs_info, start);
1042 if (!block_group) {
1043 ASSERT(0);
1044 ret = -ENOENT;
1045 goto out;
1046 }
1047
1048 mutex_lock(&block_group->free_space_lock);
1049 ret = __add_to_free_space_tree(trans, block_group, path, start, size);
1050 mutex_unlock(&block_group->free_space_lock);
1051
1052 btrfs_put_block_group(block_group);
1053 out:
1054 btrfs_free_path(path);
1055 if (ret)
1056 btrfs_abort_transaction(trans, ret);
1057 return ret;
1058 }
1059
1060 /*
1061 * Populate the free space tree by walking the extent tree. Operations on the
1062 * extent tree that happen as a result of writes to the free space tree will go
1063 * through the normal add/remove hooks.
1064 */
populate_free_space_tree(struct btrfs_trans_handle * trans,struct btrfs_block_group * block_group)1065 static int populate_free_space_tree(struct btrfs_trans_handle *trans,
1066 struct btrfs_block_group *block_group)
1067 {
1068 struct btrfs_root *extent_root;
1069 struct btrfs_path *path, *path2;
1070 struct btrfs_key key;
1071 u64 start, end;
1072 int ret;
1073
1074 path = btrfs_alloc_path();
1075 if (!path)
1076 return -ENOMEM;
1077 path->reada = READA_FORWARD;
1078
1079 path2 = btrfs_alloc_path();
1080 if (!path2) {
1081 btrfs_free_path(path);
1082 return -ENOMEM;
1083 }
1084
1085 ret = add_new_free_space_info(trans, block_group, path2);
1086 if (ret)
1087 goto out;
1088
1089 mutex_lock(&block_group->free_space_lock);
1090
1091 /*
1092 * Iterate through all of the extent and metadata items in this block
1093 * group, adding the free space between them and the free space at the
1094 * end. Note that EXTENT_ITEM and METADATA_ITEM are less than
1095 * BLOCK_GROUP_ITEM, so an extent may precede the block group that it's
1096 * contained in.
1097 */
1098 key.objectid = block_group->start;
1099 key.type = BTRFS_EXTENT_ITEM_KEY;
1100 key.offset = 0;
1101
1102 extent_root = btrfs_extent_root(trans->fs_info, key.objectid);
1103 ret = btrfs_search_slot_for_read(extent_root, &key, path, 1, 0);
1104 if (ret < 0)
1105 goto out_locked;
1106 ASSERT(ret == 0);
1107
1108 start = block_group->start;
1109 end = block_group->start + block_group->length;
1110 while (1) {
1111 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
1112
1113 if (key.type == BTRFS_EXTENT_ITEM_KEY ||
1114 key.type == BTRFS_METADATA_ITEM_KEY) {
1115 if (key.objectid >= end)
1116 break;
1117
1118 if (start < key.objectid) {
1119 ret = __add_to_free_space_tree(trans,
1120 block_group,
1121 path2, start,
1122 key.objectid -
1123 start);
1124 if (ret)
1125 goto out_locked;
1126 }
1127 start = key.objectid;
1128 if (key.type == BTRFS_METADATA_ITEM_KEY)
1129 start += trans->fs_info->nodesize;
1130 else
1131 start += key.offset;
1132 } else if (key.type == BTRFS_BLOCK_GROUP_ITEM_KEY) {
1133 if (key.objectid != block_group->start)
1134 break;
1135 }
1136
1137 ret = btrfs_next_item(extent_root, path);
1138 if (ret < 0)
1139 goto out_locked;
1140 if (ret)
1141 break;
1142 }
1143 if (start < end) {
1144 ret = __add_to_free_space_tree(trans, block_group, path2,
1145 start, end - start);
1146 if (ret)
1147 goto out_locked;
1148 }
1149
1150 ret = 0;
1151 out_locked:
1152 mutex_unlock(&block_group->free_space_lock);
1153 out:
1154 btrfs_free_path(path2);
1155 btrfs_free_path(path);
1156 return ret;
1157 }
1158
btrfs_create_free_space_tree(struct btrfs_fs_info * fs_info)1159 int btrfs_create_free_space_tree(struct btrfs_fs_info *fs_info)
1160 {
1161 struct btrfs_trans_handle *trans;
1162 struct btrfs_root *tree_root = fs_info->tree_root;
1163 struct btrfs_root *free_space_root;
1164 struct btrfs_block_group *block_group;
1165 struct rb_node *node;
1166 int ret;
1167
1168 trans = btrfs_start_transaction(tree_root, 0);
1169 if (IS_ERR(trans))
1170 return PTR_ERR(trans);
1171
1172 set_bit(BTRFS_FS_CREATING_FREE_SPACE_TREE, &fs_info->flags);
1173 set_bit(BTRFS_FS_FREE_SPACE_TREE_UNTRUSTED, &fs_info->flags);
1174 free_space_root = btrfs_create_tree(trans,
1175 BTRFS_FREE_SPACE_TREE_OBJECTID);
1176 if (IS_ERR(free_space_root)) {
1177 ret = PTR_ERR(free_space_root);
1178 goto abort;
1179 }
1180 ret = btrfs_global_root_insert(free_space_root);
1181 if (ret) {
1182 btrfs_put_root(free_space_root);
1183 goto abort;
1184 }
1185
1186 node = rb_first_cached(&fs_info->block_group_cache_tree);
1187 while (node) {
1188 block_group = rb_entry(node, struct btrfs_block_group,
1189 cache_node);
1190 ret = populate_free_space_tree(trans, block_group);
1191 if (ret)
1192 goto abort;
1193 node = rb_next(node);
1194 }
1195
1196 btrfs_set_fs_compat_ro(fs_info, FREE_SPACE_TREE);
1197 btrfs_set_fs_compat_ro(fs_info, FREE_SPACE_TREE_VALID);
1198 clear_bit(BTRFS_FS_CREATING_FREE_SPACE_TREE, &fs_info->flags);
1199 ret = btrfs_commit_transaction(trans);
1200
1201 /*
1202 * Now that we've committed the transaction any reading of our commit
1203 * root will be safe, so we can cache from the free space tree now.
1204 */
1205 clear_bit(BTRFS_FS_FREE_SPACE_TREE_UNTRUSTED, &fs_info->flags);
1206 return ret;
1207
1208 abort:
1209 clear_bit(BTRFS_FS_CREATING_FREE_SPACE_TREE, &fs_info->flags);
1210 clear_bit(BTRFS_FS_FREE_SPACE_TREE_UNTRUSTED, &fs_info->flags);
1211 btrfs_abort_transaction(trans, ret);
1212 btrfs_end_transaction(trans);
1213 return ret;
1214 }
1215
clear_free_space_tree(struct btrfs_trans_handle * trans,struct btrfs_root * root)1216 static int clear_free_space_tree(struct btrfs_trans_handle *trans,
1217 struct btrfs_root *root)
1218 {
1219 struct btrfs_path *path;
1220 struct btrfs_key key;
1221 int nr;
1222 int ret;
1223
1224 path = btrfs_alloc_path();
1225 if (!path)
1226 return -ENOMEM;
1227
1228 key.objectid = 0;
1229 key.type = 0;
1230 key.offset = 0;
1231
1232 while (1) {
1233 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
1234 if (ret < 0)
1235 goto out;
1236
1237 nr = btrfs_header_nritems(path->nodes[0]);
1238 if (!nr)
1239 break;
1240
1241 path->slots[0] = 0;
1242 ret = btrfs_del_items(trans, root, path, 0, nr);
1243 if (ret)
1244 goto out;
1245
1246 btrfs_release_path(path);
1247 }
1248
1249 ret = 0;
1250 out:
1251 btrfs_free_path(path);
1252 return ret;
1253 }
1254
btrfs_delete_free_space_tree(struct btrfs_fs_info * fs_info)1255 int btrfs_delete_free_space_tree(struct btrfs_fs_info *fs_info)
1256 {
1257 struct btrfs_trans_handle *trans;
1258 struct btrfs_root *tree_root = fs_info->tree_root;
1259 struct btrfs_key key = {
1260 .objectid = BTRFS_FREE_SPACE_TREE_OBJECTID,
1261 .type = BTRFS_ROOT_ITEM_KEY,
1262 .offset = 0,
1263 };
1264 struct btrfs_root *free_space_root = btrfs_global_root(fs_info, &key);
1265 int ret;
1266
1267 trans = btrfs_start_transaction(tree_root, 0);
1268 if (IS_ERR(trans))
1269 return PTR_ERR(trans);
1270
1271 btrfs_clear_fs_compat_ro(fs_info, FREE_SPACE_TREE);
1272 btrfs_clear_fs_compat_ro(fs_info, FREE_SPACE_TREE_VALID);
1273
1274 ret = clear_free_space_tree(trans, free_space_root);
1275 if (ret)
1276 goto abort;
1277
1278 ret = btrfs_del_root(trans, &free_space_root->root_key);
1279 if (ret)
1280 goto abort;
1281
1282 btrfs_global_root_delete(free_space_root);
1283
1284 spin_lock(&fs_info->trans_lock);
1285 list_del(&free_space_root->dirty_list);
1286 spin_unlock(&fs_info->trans_lock);
1287
1288 btrfs_tree_lock(free_space_root->node);
1289 btrfs_clear_buffer_dirty(trans, free_space_root->node);
1290 btrfs_tree_unlock(free_space_root->node);
1291 btrfs_free_tree_block(trans, btrfs_root_id(free_space_root),
1292 free_space_root->node, 0, 1);
1293
1294 btrfs_put_root(free_space_root);
1295
1296 return btrfs_commit_transaction(trans);
1297
1298 abort:
1299 btrfs_abort_transaction(trans, ret);
1300 btrfs_end_transaction(trans);
1301 return ret;
1302 }
1303
btrfs_rebuild_free_space_tree(struct btrfs_fs_info * fs_info)1304 int btrfs_rebuild_free_space_tree(struct btrfs_fs_info *fs_info)
1305 {
1306 struct btrfs_trans_handle *trans;
1307 struct btrfs_key key = {
1308 .objectid = BTRFS_FREE_SPACE_TREE_OBJECTID,
1309 .type = BTRFS_ROOT_ITEM_KEY,
1310 .offset = 0,
1311 };
1312 struct btrfs_root *free_space_root = btrfs_global_root(fs_info, &key);
1313 struct rb_node *node;
1314 int ret;
1315
1316 trans = btrfs_start_transaction(free_space_root, 1);
1317 if (IS_ERR(trans))
1318 return PTR_ERR(trans);
1319
1320 set_bit(BTRFS_FS_CREATING_FREE_SPACE_TREE, &fs_info->flags);
1321 set_bit(BTRFS_FS_FREE_SPACE_TREE_UNTRUSTED, &fs_info->flags);
1322
1323 ret = clear_free_space_tree(trans, free_space_root);
1324 if (ret)
1325 goto abort;
1326
1327 node = rb_first_cached(&fs_info->block_group_cache_tree);
1328 while (node) {
1329 struct btrfs_block_group *block_group;
1330
1331 block_group = rb_entry(node, struct btrfs_block_group,
1332 cache_node);
1333 ret = populate_free_space_tree(trans, block_group);
1334 if (ret)
1335 goto abort;
1336 node = rb_next(node);
1337 }
1338
1339 btrfs_set_fs_compat_ro(fs_info, FREE_SPACE_TREE);
1340 btrfs_set_fs_compat_ro(fs_info, FREE_SPACE_TREE_VALID);
1341 clear_bit(BTRFS_FS_CREATING_FREE_SPACE_TREE, &fs_info->flags);
1342
1343 ret = btrfs_commit_transaction(trans);
1344 clear_bit(BTRFS_FS_FREE_SPACE_TREE_UNTRUSTED, &fs_info->flags);
1345 return ret;
1346 abort:
1347 btrfs_abort_transaction(trans, ret);
1348 btrfs_end_transaction(trans);
1349 return ret;
1350 }
1351
__add_block_group_free_space(struct btrfs_trans_handle * trans,struct btrfs_block_group * block_group,struct btrfs_path * path)1352 static int __add_block_group_free_space(struct btrfs_trans_handle *trans,
1353 struct btrfs_block_group *block_group,
1354 struct btrfs_path *path)
1355 {
1356 int ret;
1357
1358 clear_bit(BLOCK_GROUP_FLAG_NEEDS_FREE_SPACE, &block_group->runtime_flags);
1359
1360 ret = add_new_free_space_info(trans, block_group, path);
1361 if (ret)
1362 return ret;
1363
1364 return __add_to_free_space_tree(trans, block_group, path,
1365 block_group->start,
1366 block_group->length);
1367 }
1368
add_block_group_free_space(struct btrfs_trans_handle * trans,struct btrfs_block_group * block_group)1369 int add_block_group_free_space(struct btrfs_trans_handle *trans,
1370 struct btrfs_block_group *block_group)
1371 {
1372 struct btrfs_fs_info *fs_info = trans->fs_info;
1373 struct btrfs_path *path = NULL;
1374 int ret = 0;
1375
1376 if (!btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE))
1377 return 0;
1378
1379 mutex_lock(&block_group->free_space_lock);
1380 if (!test_bit(BLOCK_GROUP_FLAG_NEEDS_FREE_SPACE, &block_group->runtime_flags))
1381 goto out;
1382
1383 path = btrfs_alloc_path();
1384 if (!path) {
1385 ret = -ENOMEM;
1386 goto out;
1387 }
1388
1389 ret = __add_block_group_free_space(trans, block_group, path);
1390
1391 out:
1392 btrfs_free_path(path);
1393 mutex_unlock(&block_group->free_space_lock);
1394 if (ret)
1395 btrfs_abort_transaction(trans, ret);
1396 return ret;
1397 }
1398
remove_block_group_free_space(struct btrfs_trans_handle * trans,struct btrfs_block_group * block_group)1399 int remove_block_group_free_space(struct btrfs_trans_handle *trans,
1400 struct btrfs_block_group *block_group)
1401 {
1402 struct btrfs_root *root = btrfs_free_space_root(block_group);
1403 struct btrfs_path *path;
1404 struct btrfs_key key, found_key;
1405 struct extent_buffer *leaf;
1406 u64 start, end;
1407 int done = 0, nr;
1408 int ret;
1409
1410 if (!btrfs_fs_compat_ro(trans->fs_info, FREE_SPACE_TREE))
1411 return 0;
1412
1413 if (test_bit(BLOCK_GROUP_FLAG_NEEDS_FREE_SPACE, &block_group->runtime_flags)) {
1414 /* We never added this block group to the free space tree. */
1415 return 0;
1416 }
1417
1418 path = btrfs_alloc_path();
1419 if (!path) {
1420 ret = -ENOMEM;
1421 goto out;
1422 }
1423
1424 start = block_group->start;
1425 end = block_group->start + block_group->length;
1426
1427 key.objectid = end - 1;
1428 key.type = (u8)-1;
1429 key.offset = (u64)-1;
1430
1431 while (!done) {
1432 ret = btrfs_search_prev_slot(trans, root, &key, path, -1, 1);
1433 if (ret)
1434 goto out;
1435
1436 leaf = path->nodes[0];
1437 nr = 0;
1438 path->slots[0]++;
1439 while (path->slots[0] > 0) {
1440 btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0] - 1);
1441
1442 if (found_key.type == BTRFS_FREE_SPACE_INFO_KEY) {
1443 ASSERT(found_key.objectid == block_group->start);
1444 ASSERT(found_key.offset == block_group->length);
1445 done = 1;
1446 nr++;
1447 path->slots[0]--;
1448 break;
1449 } else if (found_key.type == BTRFS_FREE_SPACE_EXTENT_KEY ||
1450 found_key.type == BTRFS_FREE_SPACE_BITMAP_KEY) {
1451 ASSERT(found_key.objectid >= start);
1452 ASSERT(found_key.objectid < end);
1453 ASSERT(found_key.objectid + found_key.offset <= end);
1454 nr++;
1455 path->slots[0]--;
1456 } else {
1457 ASSERT(0);
1458 }
1459 }
1460
1461 ret = btrfs_del_items(trans, root, path, path->slots[0], nr);
1462 if (ret)
1463 goto out;
1464 btrfs_release_path(path);
1465 }
1466
1467 ret = 0;
1468 out:
1469 btrfs_free_path(path);
1470 if (ret)
1471 btrfs_abort_transaction(trans, ret);
1472 return ret;
1473 }
1474
load_free_space_bitmaps(struct btrfs_caching_control * caching_ctl,struct btrfs_path * path,u32 expected_extent_count)1475 static int load_free_space_bitmaps(struct btrfs_caching_control *caching_ctl,
1476 struct btrfs_path *path,
1477 u32 expected_extent_count)
1478 {
1479 struct btrfs_block_group *block_group;
1480 struct btrfs_fs_info *fs_info;
1481 struct btrfs_root *root;
1482 struct btrfs_key key;
1483 int prev_bit = 0, bit;
1484 /* Initialize to silence GCC. */
1485 u64 extent_start = 0;
1486 u64 end, offset;
1487 u64 total_found = 0;
1488 u32 extent_count = 0;
1489 int ret;
1490
1491 block_group = caching_ctl->block_group;
1492 fs_info = block_group->fs_info;
1493 root = btrfs_free_space_root(block_group);
1494
1495 end = block_group->start + block_group->length;
1496
1497 while (1) {
1498 ret = btrfs_next_item(root, path);
1499 if (ret < 0)
1500 goto out;
1501 if (ret)
1502 break;
1503
1504 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
1505
1506 if (key.type == BTRFS_FREE_SPACE_INFO_KEY)
1507 break;
1508
1509 ASSERT(key.type == BTRFS_FREE_SPACE_BITMAP_KEY);
1510 ASSERT(key.objectid < end && key.objectid + key.offset <= end);
1511
1512 offset = key.objectid;
1513 while (offset < key.objectid + key.offset) {
1514 bit = free_space_test_bit(block_group, path, offset);
1515 if (prev_bit == 0 && bit == 1) {
1516 extent_start = offset;
1517 } else if (prev_bit == 1 && bit == 0) {
1518 u64 space_added;
1519
1520 ret = btrfs_add_new_free_space(block_group,
1521 extent_start,
1522 offset,
1523 &space_added);
1524 if (ret)
1525 goto out;
1526 total_found += space_added;
1527 if (total_found > CACHING_CTL_WAKE_UP) {
1528 total_found = 0;
1529 wake_up(&caching_ctl->wait);
1530 }
1531 extent_count++;
1532 }
1533 prev_bit = bit;
1534 offset += fs_info->sectorsize;
1535 }
1536 }
1537 if (prev_bit == 1) {
1538 ret = btrfs_add_new_free_space(block_group, extent_start, end, NULL);
1539 if (ret)
1540 goto out;
1541 extent_count++;
1542 }
1543
1544 if (extent_count != expected_extent_count) {
1545 btrfs_err(fs_info,
1546 "incorrect extent count for %llu; counted %u, expected %u",
1547 block_group->start, extent_count,
1548 expected_extent_count);
1549 ASSERT(0);
1550 ret = -EIO;
1551 goto out;
1552 }
1553
1554 ret = 0;
1555 out:
1556 return ret;
1557 }
1558
load_free_space_extents(struct btrfs_caching_control * caching_ctl,struct btrfs_path * path,u32 expected_extent_count)1559 static int load_free_space_extents(struct btrfs_caching_control *caching_ctl,
1560 struct btrfs_path *path,
1561 u32 expected_extent_count)
1562 {
1563 struct btrfs_block_group *block_group;
1564 struct btrfs_fs_info *fs_info;
1565 struct btrfs_root *root;
1566 struct btrfs_key key;
1567 u64 end;
1568 u64 total_found = 0;
1569 u32 extent_count = 0;
1570 int ret;
1571
1572 block_group = caching_ctl->block_group;
1573 fs_info = block_group->fs_info;
1574 root = btrfs_free_space_root(block_group);
1575
1576 end = block_group->start + block_group->length;
1577
1578 while (1) {
1579 u64 space_added;
1580
1581 ret = btrfs_next_item(root, path);
1582 if (ret < 0)
1583 goto out;
1584 if (ret)
1585 break;
1586
1587 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
1588
1589 if (key.type == BTRFS_FREE_SPACE_INFO_KEY)
1590 break;
1591
1592 ASSERT(key.type == BTRFS_FREE_SPACE_EXTENT_KEY);
1593 ASSERT(key.objectid < end && key.objectid + key.offset <= end);
1594
1595 ret = btrfs_add_new_free_space(block_group, key.objectid,
1596 key.objectid + key.offset,
1597 &space_added);
1598 if (ret)
1599 goto out;
1600 total_found += space_added;
1601 if (total_found > CACHING_CTL_WAKE_UP) {
1602 total_found = 0;
1603 wake_up(&caching_ctl->wait);
1604 }
1605 extent_count++;
1606 }
1607
1608 if (extent_count != expected_extent_count) {
1609 btrfs_err(fs_info,
1610 "incorrect extent count for %llu; counted %u, expected %u",
1611 block_group->start, extent_count,
1612 expected_extent_count);
1613 ASSERT(0);
1614 ret = -EIO;
1615 goto out;
1616 }
1617
1618 ret = 0;
1619 out:
1620 return ret;
1621 }
1622
load_free_space_tree(struct btrfs_caching_control * caching_ctl)1623 int load_free_space_tree(struct btrfs_caching_control *caching_ctl)
1624 {
1625 struct btrfs_block_group *block_group;
1626 struct btrfs_free_space_info *info;
1627 struct btrfs_path *path;
1628 u32 extent_count, flags;
1629 int ret;
1630
1631 block_group = caching_ctl->block_group;
1632
1633 path = btrfs_alloc_path();
1634 if (!path)
1635 return -ENOMEM;
1636
1637 /*
1638 * Just like caching_thread() doesn't want to deadlock on the extent
1639 * tree, we don't want to deadlock on the free space tree.
1640 */
1641 path->skip_locking = 1;
1642 path->search_commit_root = 1;
1643 path->reada = READA_FORWARD;
1644
1645 info = search_free_space_info(NULL, block_group, path, 0);
1646 if (IS_ERR(info)) {
1647 ret = PTR_ERR(info);
1648 goto out;
1649 }
1650 extent_count = btrfs_free_space_extent_count(path->nodes[0], info);
1651 flags = btrfs_free_space_flags(path->nodes[0], info);
1652
1653 /*
1654 * We left path pointing to the free space info item, so now
1655 * load_free_space_foo can just iterate through the free space tree from
1656 * there.
1657 */
1658 if (flags & BTRFS_FREE_SPACE_USING_BITMAPS)
1659 ret = load_free_space_bitmaps(caching_ctl, path, extent_count);
1660 else
1661 ret = load_free_space_extents(caching_ctl, path, extent_count);
1662
1663 out:
1664 btrfs_free_path(path);
1665 return ret;
1666 }
1667
