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 | |
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(fs_info: block_group->fs_info, key: &key); |
36 | } |
37 | |
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(dividend: cache->length + bitmap_range - 1, divisor: 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(dividend: total_bitmap_size, |
57 | divisor: 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 | |
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: &key, data_size: 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(eb: leaf, s: info, val: 0); |
91 | btrfs_set_free_space_flags(eb: leaf, s: info, val: 0); |
92 | btrfs_mark_buffer_dirty(trans, buf: leaf); |
93 | |
94 | ret = 0; |
95 | out: |
96 | btrfs_release_path(p: path); |
97 | return ret; |
98 | } |
99 | |
100 | EXPORT_FOR_TESTS |
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: &key, p: path, ins_len: 0, cow); |
116 | if (ret < 0) |
117 | return ERR_PTR(error: 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(error: -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 | */ |
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 | |
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 | |
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(size: bitmap_rounded_size, GFP_KERNEL); |
180 | memalloc_nofs_restore(flags: nofs_flag); |
181 | return ret; |
182 | } |
183 | |
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 |
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, size: 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: &key, p: path, ins_len: -1, cow: 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(eb: leaf, cpu_key: &found_key, nr: 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(dividend: found_key.objectid - start, |
261 | divisor: fs_info->sectorsize); |
262 | last = div_u64(dividend: found_key.objectid + found_key.offset - start, |
263 | divisor: fs_info->sectorsize); |
264 | le_bitmap_set(map: bitmap, start: first, len: 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, slot: path->slots[0], nr); |
275 | if (ret) |
276 | goto out; |
277 | btrfs_release_path(p: path); |
278 | } |
279 | |
280 | info = search_free_space_info(trans, block_group, path, cow: 1); |
281 | if (IS_ERR(ptr: info)) { |
282 | ret = PTR_ERR(ptr: info); |
283 | goto out; |
284 | } |
285 | leaf = path->nodes[0]; |
286 | flags = btrfs_free_space_flags(eb: leaf, s: info); |
287 | flags |= BTRFS_FREE_SPACE_USING_BITMAPS; |
288 | btrfs_set_free_space_flags(eb: leaf, s: info, val: flags); |
289 | expected_extent_count = btrfs_free_space_extent_count(eb: leaf, s: info); |
290 | btrfs_mark_buffer_dirty(trans, buf: leaf); |
291 | btrfs_release_path(p: 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, size: 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: &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(eb: leaf, src: bitmap_cursor, start: ptr, |
326 | len: data_size); |
327 | btrfs_mark_buffer_dirty(trans, buf: leaf); |
328 | btrfs_release_path(p: path); |
329 | |
330 | i += extent_size; |
331 | bitmap_cursor += data_size; |
332 | } |
333 | |
334 | ret = 0; |
335 | out: |
336 | kvfree(addr: bitmap); |
337 | if (ret) |
338 | btrfs_abort_transaction(trans, ret); |
339 | return ret; |
340 | } |
341 | |
342 | EXPORT_FOR_TESTS |
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, size: 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: &key, p: path, ins_len: -1, cow: 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(eb: leaf, cpu_key: &found_key, nr: 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(dividend: found_key.objectid - start, |
400 | divisor: fs_info->sectorsize * |
401 | BITS_PER_BYTE); |
402 | bitmap_cursor = ((char *)bitmap) + bitmap_pos; |
403 | data_size = free_space_bitmap_size(fs_info, |
404 | size: found_key.offset); |
405 | |
406 | ptr = btrfs_item_ptr_offset(leaf, path->slots[0] - 1); |
407 | read_extent_buffer(eb: leaf, dst: bitmap_cursor, start: ptr, |
408 | len: 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, slot: path->slots[0], nr); |
418 | if (ret) |
419 | goto out; |
420 | btrfs_release_path(p: path); |
421 | } |
422 | |
423 | info = search_free_space_info(trans, block_group, path, cow: 1); |
424 | if (IS_ERR(ptr: info)) { |
425 | ret = PTR_ERR(ptr: info); |
426 | goto out; |
427 | } |
428 | leaf = path->nodes[0]; |
429 | flags = btrfs_free_space_flags(eb: leaf, s: info); |
430 | flags &= ~BTRFS_FREE_SPACE_USING_BITMAPS; |
431 | btrfs_set_free_space_flags(eb: leaf, s: info, val: flags); |
432 | expected_extent_count = btrfs_free_space_extent_count(eb: leaf, s: info); |
433 | btrfs_mark_buffer_dirty(trans, buf: leaf); |
434 | btrfs_release_path(p: path); |
435 | |
436 | nrbits = block_group->length >> block_group->fs_info->sectorsize_bits; |
437 | start_bit = find_next_bit_le(addr: bitmap, size: nrbits, offset: 0); |
438 | |
439 | while (start_bit < nrbits) { |
440 | end_bit = find_next_zero_bit_le(addr: bitmap, size: nrbits, offset: 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: &key, data_size: 0); |
448 | if (ret) |
449 | goto out; |
450 | btrfs_release_path(p: path); |
451 | |
452 | extent_count++; |
453 | |
454 | start_bit = find_next_bit_le(addr: bitmap, size: nrbits, offset: 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(addr: bitmap); |
470 | if (ret) |
471 | btrfs_abort_transaction(trans, ret); |
472 | return ret; |
473 | } |
474 | |
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, cow: 1); |
489 | if (IS_ERR(ptr: info)) { |
490 | ret = PTR_ERR(ptr: info); |
491 | goto out; |
492 | } |
493 | flags = btrfs_free_space_flags(eb: path->nodes[0], s: info); |
494 | extent_count = btrfs_free_space_extent_count(eb: path->nodes[0], s: info); |
495 | |
496 | extent_count += new_extents; |
497 | btrfs_set_free_space_extent_count(eb: path->nodes[0], s: info, val: extent_count); |
498 | btrfs_mark_buffer_dirty(trans, buf: path->nodes[0]); |
499 | btrfs_release_path(p: 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 |
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(eb: leaf, cpu_key: &key, nr: 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(dividend: offset - found_start, |
532 | divisor: block_group->fs_info->sectorsize); |
533 | return !!extent_buffer_test_bit(eb: leaf, start: ptr, pos: i); |
534 | } |
535 | |
536 | static void free_space_set_bits(struct btrfs_trans_handle *trans, |
537 | struct btrfs_block_group *block_group, |
538 | struct btrfs_path *path, u64 *start, u64 *size, |
539 | int bit) |
540 | { |
541 | struct btrfs_fs_info *fs_info = block_group->fs_info; |
542 | struct extent_buffer *leaf; |
543 | struct btrfs_key key; |
544 | u64 end = *start + *size; |
545 | u64 found_start, found_end; |
546 | unsigned long ptr, first, last; |
547 | |
548 | leaf = path->nodes[0]; |
549 | btrfs_item_key_to_cpu(eb: leaf, cpu_key: &key, nr: path->slots[0]); |
550 | ASSERT(key.type == BTRFS_FREE_SPACE_BITMAP_KEY); |
551 | |
552 | found_start = key.objectid; |
553 | found_end = key.objectid + key.offset; |
554 | ASSERT(*start >= found_start && *start < found_end); |
555 | ASSERT(end > found_start); |
556 | |
557 | if (end > found_end) |
558 | end = found_end; |
559 | |
560 | ptr = btrfs_item_ptr_offset(leaf, path->slots[0]); |
561 | first = (*start - found_start) >> fs_info->sectorsize_bits; |
562 | last = (end - found_start) >> fs_info->sectorsize_bits; |
563 | if (bit) |
564 | extent_buffer_bitmap_set(eb: leaf, start: ptr, pos: first, len: last - first); |
565 | else |
566 | extent_buffer_bitmap_clear(eb: leaf, start: ptr, pos: first, len: last - first); |
567 | btrfs_mark_buffer_dirty(trans, buf: leaf); |
568 | |
569 | *size -= end - *start; |
570 | *start = end; |
571 | } |
572 | |
573 | /* |
574 | * We can't use btrfs_next_item() in modify_free_space_bitmap() because |
575 | * btrfs_next_leaf() doesn't get the path for writing. We can forgo the fancy |
576 | * tree walking in btrfs_next_leaf() anyways because we know exactly what we're |
577 | * looking for. |
578 | */ |
579 | static int free_space_next_bitmap(struct btrfs_trans_handle *trans, |
580 | struct btrfs_root *root, struct btrfs_path *p) |
581 | { |
582 | struct btrfs_key key; |
583 | |
584 | if (p->slots[0] + 1 < btrfs_header_nritems(eb: p->nodes[0])) { |
585 | p->slots[0]++; |
586 | return 0; |
587 | } |
588 | |
589 | btrfs_item_key_to_cpu(eb: p->nodes[0], cpu_key: &key, nr: p->slots[0]); |
590 | btrfs_release_path(p); |
591 | |
592 | key.objectid += key.offset; |
593 | key.type = (u8)-1; |
594 | key.offset = (u64)-1; |
595 | |
596 | return btrfs_search_prev_slot(trans, root, key: &key, p, ins_len: 0, cow: 1); |
597 | } |
598 | |
599 | /* |
600 | * If remove is 1, then we are removing free space, thus clearing bits in the |
601 | * bitmap. If remove is 0, then we are adding free space, thus setting bits in |
602 | * the bitmap. |
603 | */ |
604 | static int modify_free_space_bitmap(struct btrfs_trans_handle *trans, |
605 | struct btrfs_block_group *block_group, |
606 | struct btrfs_path *path, |
607 | u64 start, u64 size, int remove) |
608 | { |
609 | struct btrfs_root *root = btrfs_free_space_root(block_group); |
610 | struct btrfs_key key; |
611 | u64 end = start + size; |
612 | u64 cur_start, cur_size; |
613 | int prev_bit, next_bit; |
614 | int new_extents; |
615 | int ret; |
616 | |
617 | /* |
618 | * Read the bit for the block immediately before the extent of space if |
619 | * that block is within the block group. |
620 | */ |
621 | if (start > block_group->start) { |
622 | u64 prev_block = start - block_group->fs_info->sectorsize; |
623 | |
624 | key.objectid = prev_block; |
625 | key.type = (u8)-1; |
626 | key.offset = (u64)-1; |
627 | |
628 | ret = btrfs_search_prev_slot(trans, root, key: &key, p: path, ins_len: 0, cow: 1); |
629 | if (ret) |
630 | goto out; |
631 | |
632 | prev_bit = free_space_test_bit(block_group, path, offset: prev_block); |
633 | |
634 | /* The previous block may have been in the previous bitmap. */ |
635 | btrfs_item_key_to_cpu(eb: path->nodes[0], cpu_key: &key, nr: path->slots[0]); |
636 | if (start >= key.objectid + key.offset) { |
637 | ret = free_space_next_bitmap(trans, root, p: path); |
638 | if (ret) |
639 | goto out; |
640 | } |
641 | } else { |
642 | key.objectid = start; |
643 | key.type = (u8)-1; |
644 | key.offset = (u64)-1; |
645 | |
646 | ret = btrfs_search_prev_slot(trans, root, key: &key, p: path, ins_len: 0, cow: 1); |
647 | if (ret) |
648 | goto out; |
649 | |
650 | prev_bit = -1; |
651 | } |
652 | |
653 | /* |
654 | * Iterate over all of the bitmaps overlapped by the extent of space, |
655 | * clearing/setting bits as required. |
656 | */ |
657 | cur_start = start; |
658 | cur_size = size; |
659 | while (1) { |
660 | free_space_set_bits(trans, block_group, path, start: &cur_start, size: &cur_size, |
661 | bit: !remove); |
662 | if (cur_size == 0) |
663 | break; |
664 | ret = free_space_next_bitmap(trans, root, p: path); |
665 | if (ret) |
666 | goto out; |
667 | } |
668 | |
669 | /* |
670 | * Read the bit for the block immediately after the extent of space if |
671 | * that block is within the block group. |
672 | */ |
673 | if (end < block_group->start + block_group->length) { |
674 | /* The next block may be in the next bitmap. */ |
675 | btrfs_item_key_to_cpu(eb: path->nodes[0], cpu_key: &key, nr: path->slots[0]); |
676 | if (end >= key.objectid + key.offset) { |
677 | ret = free_space_next_bitmap(trans, root, p: path); |
678 | if (ret) |
679 | goto out; |
680 | } |
681 | |
682 | next_bit = free_space_test_bit(block_group, path, offset: end); |
683 | } else { |
684 | next_bit = -1; |
685 | } |
686 | |
687 | if (remove) { |
688 | new_extents = -1; |
689 | if (prev_bit == 1) { |
690 | /* Leftover on the left. */ |
691 | new_extents++; |
692 | } |
693 | if (next_bit == 1) { |
694 | /* Leftover on the right. */ |
695 | new_extents++; |
696 | } |
697 | } else { |
698 | new_extents = 1; |
699 | if (prev_bit == 1) { |
700 | /* Merging with neighbor on the left. */ |
701 | new_extents--; |
702 | } |
703 | if (next_bit == 1) { |
704 | /* Merging with neighbor on the right. */ |
705 | new_extents--; |
706 | } |
707 | } |
708 | |
709 | btrfs_release_path(p: path); |
710 | ret = update_free_space_extent_count(trans, block_group, path, |
711 | new_extents); |
712 | |
713 | out: |
714 | return ret; |
715 | } |
716 | |
717 | static int remove_free_space_extent(struct btrfs_trans_handle *trans, |
718 | struct btrfs_block_group *block_group, |
719 | struct btrfs_path *path, |
720 | u64 start, u64 size) |
721 | { |
722 | struct btrfs_root *root = btrfs_free_space_root(block_group); |
723 | struct btrfs_key key; |
724 | u64 found_start, found_end; |
725 | u64 end = start + size; |
726 | int new_extents = -1; |
727 | int ret; |
728 | |
729 | key.objectid = start; |
730 | key.type = (u8)-1; |
731 | key.offset = (u64)-1; |
732 | |
733 | ret = btrfs_search_prev_slot(trans, root, key: &key, p: path, ins_len: -1, cow: 1); |
734 | if (ret) |
735 | goto out; |
736 | |
737 | btrfs_item_key_to_cpu(eb: path->nodes[0], cpu_key: &key, nr: path->slots[0]); |
738 | |
739 | ASSERT(key.type == BTRFS_FREE_SPACE_EXTENT_KEY); |
740 | |
741 | found_start = key.objectid; |
742 | found_end = key.objectid + key.offset; |
743 | ASSERT(start >= found_start && end <= found_end); |
744 | |
745 | /* |
746 | * Okay, now that we've found the free space extent which contains the |
747 | * free space that we are removing, there are four cases: |
748 | * |
749 | * 1. We're using the whole extent: delete the key we found and |
750 | * decrement the free space extent count. |
751 | * 2. We are using part of the extent starting at the beginning: delete |
752 | * the key we found and insert a new key representing the leftover at |
753 | * the end. There is no net change in the number of extents. |
754 | * 3. We are using part of the extent ending at the end: delete the key |
755 | * we found and insert a new key representing the leftover at the |
756 | * beginning. There is no net change in the number of extents. |
757 | * 4. We are using part of the extent in the middle: delete the key we |
758 | * found and insert two new keys representing the leftovers on each |
759 | * side. Where we used to have one extent, we now have two, so increment |
760 | * the extent count. We may need to convert the block group to bitmaps |
761 | * as a result. |
762 | */ |
763 | |
764 | /* Delete the existing key (cases 1-4). */ |
765 | ret = btrfs_del_item(trans, root, path); |
766 | if (ret) |
767 | goto out; |
768 | |
769 | /* Add a key for leftovers at the beginning (cases 3 and 4). */ |
770 | if (start > found_start) { |
771 | key.objectid = found_start; |
772 | key.type = BTRFS_FREE_SPACE_EXTENT_KEY; |
773 | key.offset = start - found_start; |
774 | |
775 | btrfs_release_path(p: path); |
776 | ret = btrfs_insert_empty_item(trans, root, path, key: &key, data_size: 0); |
777 | if (ret) |
778 | goto out; |
779 | new_extents++; |
780 | } |
781 | |
782 | /* Add a key for leftovers at the end (cases 2 and 4). */ |
783 | if (end < found_end) { |
784 | key.objectid = end; |
785 | key.type = BTRFS_FREE_SPACE_EXTENT_KEY; |
786 | key.offset = found_end - end; |
787 | |
788 | btrfs_release_path(p: path); |
789 | ret = btrfs_insert_empty_item(trans, root, path, key: &key, data_size: 0); |
790 | if (ret) |
791 | goto out; |
792 | new_extents++; |
793 | } |
794 | |
795 | btrfs_release_path(p: path); |
796 | ret = update_free_space_extent_count(trans, block_group, path, |
797 | new_extents); |
798 | |
799 | out: |
800 | return ret; |
801 | } |
802 | |
803 | EXPORT_FOR_TESTS |
804 | int __remove_from_free_space_tree(struct btrfs_trans_handle *trans, |
805 | struct btrfs_block_group *block_group, |
806 | struct btrfs_path *path, u64 start, u64 size) |
807 | { |
808 | struct btrfs_free_space_info *info; |
809 | u32 flags; |
810 | int ret; |
811 | |
812 | if (test_bit(BLOCK_GROUP_FLAG_NEEDS_FREE_SPACE, &block_group->runtime_flags)) { |
813 | ret = __add_block_group_free_space(trans, block_group, path); |
814 | if (ret) |
815 | return ret; |
816 | } |
817 | |
818 | info = search_free_space_info(NULL, block_group, path, cow: 0); |
819 | if (IS_ERR(ptr: info)) |
820 | return PTR_ERR(ptr: info); |
821 | flags = btrfs_free_space_flags(eb: path->nodes[0], s: info); |
822 | btrfs_release_path(p: path); |
823 | |
824 | if (flags & BTRFS_FREE_SPACE_USING_BITMAPS) { |
825 | return modify_free_space_bitmap(trans, block_group, path, |
826 | start, size, remove: 1); |
827 | } else { |
828 | return remove_free_space_extent(trans, block_group, path, |
829 | start, size); |
830 | } |
831 | } |
832 | |
833 | int remove_from_free_space_tree(struct btrfs_trans_handle *trans, |
834 | u64 start, u64 size) |
835 | { |
836 | struct btrfs_block_group *block_group; |
837 | struct btrfs_path *path; |
838 | int ret; |
839 | |
840 | if (!btrfs_fs_compat_ro(trans->fs_info, FREE_SPACE_TREE)) |
841 | return 0; |
842 | |
843 | path = btrfs_alloc_path(); |
844 | if (!path) { |
845 | ret = -ENOMEM; |
846 | goto out; |
847 | } |
848 | |
849 | block_group = btrfs_lookup_block_group(info: trans->fs_info, bytenr: start); |
850 | if (!block_group) { |
851 | ASSERT(0); |
852 | ret = -ENOENT; |
853 | goto out; |
854 | } |
855 | |
856 | mutex_lock(&block_group->free_space_lock); |
857 | ret = __remove_from_free_space_tree(trans, block_group, path, start, |
858 | size); |
859 | mutex_unlock(lock: &block_group->free_space_lock); |
860 | |
861 | btrfs_put_block_group(cache: block_group); |
862 | out: |
863 | btrfs_free_path(p: path); |
864 | if (ret) |
865 | btrfs_abort_transaction(trans, ret); |
866 | return ret; |
867 | } |
868 | |
869 | static int add_free_space_extent(struct btrfs_trans_handle *trans, |
870 | struct btrfs_block_group *block_group, |
871 | struct btrfs_path *path, |
872 | u64 start, u64 size) |
873 | { |
874 | struct btrfs_root *root = btrfs_free_space_root(block_group); |
875 | struct btrfs_key key, new_key; |
876 | u64 found_start, found_end; |
877 | u64 end = start + size; |
878 | int new_extents = 1; |
879 | int ret; |
880 | |
881 | /* |
882 | * We are adding a new extent of free space, but we need to merge |
883 | * extents. There are four cases here: |
884 | * |
885 | * 1. The new extent does not have any immediate neighbors to merge |
886 | * with: add the new key and increment the free space extent count. We |
887 | * may need to convert the block group to bitmaps as a result. |
888 | * 2. The new extent has an immediate neighbor before it: remove the |
889 | * previous key and insert a new key combining both of them. There is no |
890 | * net change in the number of extents. |
891 | * 3. The new extent has an immediate neighbor after it: remove the next |
892 | * key and insert a new key combining both of them. There is no net |
893 | * change in the number of extents. |
894 | * 4. The new extent has immediate neighbors on both sides: remove both |
895 | * of the keys and insert a new key combining all of them. Where we used |
896 | * to have two extents, we now have one, so decrement the extent count. |
897 | */ |
898 | |
899 | new_key.objectid = start; |
900 | new_key.type = BTRFS_FREE_SPACE_EXTENT_KEY; |
901 | new_key.offset = size; |
902 | |
903 | /* Search for a neighbor on the left. */ |
904 | if (start == block_group->start) |
905 | goto right; |
906 | key.objectid = start - 1; |
907 | key.type = (u8)-1; |
908 | key.offset = (u64)-1; |
909 | |
910 | ret = btrfs_search_prev_slot(trans, root, key: &key, p: path, ins_len: -1, cow: 1); |
911 | if (ret) |
912 | goto out; |
913 | |
914 | btrfs_item_key_to_cpu(eb: path->nodes[0], cpu_key: &key, nr: path->slots[0]); |
915 | |
916 | if (key.type != BTRFS_FREE_SPACE_EXTENT_KEY) { |
917 | ASSERT(key.type == BTRFS_FREE_SPACE_INFO_KEY); |
918 | btrfs_release_path(p: path); |
919 | goto right; |
920 | } |
921 | |
922 | found_start = key.objectid; |
923 | found_end = key.objectid + key.offset; |
924 | ASSERT(found_start >= block_group->start && |
925 | found_end > block_group->start); |
926 | ASSERT(found_start < start && found_end <= start); |
927 | |
928 | /* |
929 | * Delete the neighbor on the left and absorb it into the new key (cases |
930 | * 2 and 4). |
931 | */ |
932 | if (found_end == start) { |
933 | ret = btrfs_del_item(trans, root, path); |
934 | if (ret) |
935 | goto out; |
936 | new_key.objectid = found_start; |
937 | new_key.offset += key.offset; |
938 | new_extents--; |
939 | } |
940 | btrfs_release_path(p: path); |
941 | |
942 | right: |
943 | /* Search for a neighbor on the right. */ |
944 | if (end == block_group->start + block_group->length) |
945 | goto insert; |
946 | key.objectid = end; |
947 | key.type = (u8)-1; |
948 | key.offset = (u64)-1; |
949 | |
950 | ret = btrfs_search_prev_slot(trans, root, key: &key, p: path, ins_len: -1, cow: 1); |
951 | if (ret) |
952 | goto out; |
953 | |
954 | btrfs_item_key_to_cpu(eb: path->nodes[0], cpu_key: &key, nr: path->slots[0]); |
955 | |
956 | if (key.type != BTRFS_FREE_SPACE_EXTENT_KEY) { |
957 | ASSERT(key.type == BTRFS_FREE_SPACE_INFO_KEY); |
958 | btrfs_release_path(p: path); |
959 | goto insert; |
960 | } |
961 | |
962 | found_start = key.objectid; |
963 | found_end = key.objectid + key.offset; |
964 | ASSERT(found_start >= block_group->start && |
965 | found_end > block_group->start); |
966 | ASSERT((found_start < start && found_end <= start) || |
967 | (found_start >= end && found_end > end)); |
968 | |
969 | /* |
970 | * Delete the neighbor on the right and absorb it into the new key |
971 | * (cases 3 and 4). |
972 | */ |
973 | if (found_start == end) { |
974 | ret = btrfs_del_item(trans, root, path); |
975 | if (ret) |
976 | goto out; |
977 | new_key.offset += key.offset; |
978 | new_extents--; |
979 | } |
980 | btrfs_release_path(p: path); |
981 | |
982 | insert: |
983 | /* Insert the new key (cases 1-4). */ |
984 | ret = btrfs_insert_empty_item(trans, root, path, key: &new_key, data_size: 0); |
985 | if (ret) |
986 | goto out; |
987 | |
988 | btrfs_release_path(p: path); |
989 | ret = update_free_space_extent_count(trans, block_group, path, |
990 | new_extents); |
991 | |
992 | out: |
993 | return ret; |
994 | } |
995 | |
996 | EXPORT_FOR_TESTS |
997 | int __add_to_free_space_tree(struct btrfs_trans_handle *trans, |
998 | struct btrfs_block_group *block_group, |
999 | struct btrfs_path *path, u64 start, u64 size) |
1000 | { |
1001 | struct btrfs_free_space_info *info; |
1002 | u32 flags; |
1003 | int ret; |
1004 | |
1005 | if (test_bit(BLOCK_GROUP_FLAG_NEEDS_FREE_SPACE, &block_group->runtime_flags)) { |
1006 | ret = __add_block_group_free_space(trans, block_group, path); |
1007 | if (ret) |
1008 | return ret; |
1009 | } |
1010 | |
1011 | info = search_free_space_info(NULL, block_group, path, cow: 0); |
1012 | if (IS_ERR(ptr: info)) |
1013 | return PTR_ERR(ptr: info); |
1014 | flags = btrfs_free_space_flags(eb: path->nodes[0], s: info); |
1015 | btrfs_release_path(p: path); |
1016 | |
1017 | if (flags & BTRFS_FREE_SPACE_USING_BITMAPS) { |
1018 | return modify_free_space_bitmap(trans, block_group, path, |
1019 | start, size, remove: 0); |
1020 | } else { |
1021 | return add_free_space_extent(trans, block_group, path, start, |
1022 | size); |
1023 | } |
1024 | } |
1025 | |
1026 | int add_to_free_space_tree(struct btrfs_trans_handle *trans, |
1027 | u64 start, u64 size) |
1028 | { |
1029 | struct btrfs_block_group *block_group; |
1030 | struct btrfs_path *path; |
1031 | int ret; |
1032 | |
1033 | if (!btrfs_fs_compat_ro(trans->fs_info, FREE_SPACE_TREE)) |
1034 | return 0; |
1035 | |
1036 | path = btrfs_alloc_path(); |
1037 | if (!path) { |
1038 | ret = -ENOMEM; |
1039 | goto out; |
1040 | } |
1041 | |
1042 | block_group = btrfs_lookup_block_group(info: trans->fs_info, bytenr: start); |
1043 | if (!block_group) { |
1044 | ASSERT(0); |
1045 | ret = -ENOENT; |
1046 | goto out; |
1047 | } |
1048 | |
1049 | mutex_lock(&block_group->free_space_lock); |
1050 | ret = __add_to_free_space_tree(trans, block_group, path, start, size); |
1051 | mutex_unlock(lock: &block_group->free_space_lock); |
1052 | |
1053 | btrfs_put_block_group(cache: block_group); |
1054 | out: |
1055 | btrfs_free_path(p: path); |
1056 | if (ret) |
1057 | btrfs_abort_transaction(trans, ret); |
1058 | return ret; |
1059 | } |
1060 | |
1061 | /* |
1062 | * Populate the free space tree by walking the extent tree. Operations on the |
1063 | * extent tree that happen as a result of writes to the free space tree will go |
1064 | * through the normal add/remove hooks. |
1065 | */ |
1066 | static int populate_free_space_tree(struct btrfs_trans_handle *trans, |
1067 | struct btrfs_block_group *block_group) |
1068 | { |
1069 | struct btrfs_root *extent_root; |
1070 | struct btrfs_path *path, *path2; |
1071 | struct btrfs_key key; |
1072 | u64 start, end; |
1073 | int ret; |
1074 | |
1075 | path = btrfs_alloc_path(); |
1076 | if (!path) |
1077 | return -ENOMEM; |
1078 | path->reada = READA_FORWARD; |
1079 | |
1080 | path2 = btrfs_alloc_path(); |
1081 | if (!path2) { |
1082 | btrfs_free_path(p: path); |
1083 | return -ENOMEM; |
1084 | } |
1085 | |
1086 | ret = add_new_free_space_info(trans, block_group, path: path2); |
1087 | if (ret) |
1088 | goto out; |
1089 | |
1090 | mutex_lock(&block_group->free_space_lock); |
1091 | |
1092 | /* |
1093 | * Iterate through all of the extent and metadata items in this block |
1094 | * group, adding the free space between them and the free space at the |
1095 | * end. Note that EXTENT_ITEM and METADATA_ITEM are less than |
1096 | * BLOCK_GROUP_ITEM, so an extent may precede the block group that it's |
1097 | * contained in. |
1098 | */ |
1099 | key.objectid = block_group->start; |
1100 | key.type = BTRFS_EXTENT_ITEM_KEY; |
1101 | key.offset = 0; |
1102 | |
1103 | extent_root = btrfs_extent_root(fs_info: trans->fs_info, bytenr: key.objectid); |
1104 | ret = btrfs_search_slot_for_read(root: extent_root, key: &key, p: path, find_higher: 1, return_any: 0); |
1105 | if (ret < 0) |
1106 | goto out_locked; |
1107 | ASSERT(ret == 0); |
1108 | |
1109 | start = block_group->start; |
1110 | end = block_group->start + block_group->length; |
1111 | while (1) { |
1112 | btrfs_item_key_to_cpu(eb: path->nodes[0], cpu_key: &key, nr: path->slots[0]); |
1113 | |
1114 | if (key.type == BTRFS_EXTENT_ITEM_KEY || |
1115 | key.type == BTRFS_METADATA_ITEM_KEY) { |
1116 | if (key.objectid >= end) |
1117 | break; |
1118 | |
1119 | if (start < key.objectid) { |
1120 | ret = __add_to_free_space_tree(trans, |
1121 | block_group, |
1122 | path: path2, start, |
1123 | size: key.objectid - |
1124 | start); |
1125 | if (ret) |
1126 | goto out_locked; |
1127 | } |
1128 | start = key.objectid; |
1129 | if (key.type == BTRFS_METADATA_ITEM_KEY) |
1130 | start += trans->fs_info->nodesize; |
1131 | else |
1132 | start += key.offset; |
1133 | } else if (key.type == BTRFS_BLOCK_GROUP_ITEM_KEY) { |
1134 | if (key.objectid != block_group->start) |
1135 | break; |
1136 | } |
1137 | |
1138 | ret = btrfs_next_item(root: extent_root, p: path); |
1139 | if (ret < 0) |
1140 | goto out_locked; |
1141 | if (ret) |
1142 | break; |
1143 | } |
1144 | if (start < end) { |
1145 | ret = __add_to_free_space_tree(trans, block_group, path: path2, |
1146 | start, size: end - start); |
1147 | if (ret) |
1148 | goto out_locked; |
1149 | } |
1150 | |
1151 | ret = 0; |
1152 | out_locked: |
1153 | mutex_unlock(lock: &block_group->free_space_lock); |
1154 | out: |
1155 | btrfs_free_path(p: path2); |
1156 | btrfs_free_path(p: path); |
1157 | return ret; |
1158 | } |
1159 | |
1160 | int btrfs_create_free_space_tree(struct btrfs_fs_info *fs_info) |
1161 | { |
1162 | struct btrfs_trans_handle *trans; |
1163 | struct btrfs_root *tree_root = fs_info->tree_root; |
1164 | struct btrfs_root *free_space_root; |
1165 | struct btrfs_block_group *block_group; |
1166 | struct rb_node *node; |
1167 | int ret; |
1168 | |
1169 | trans = btrfs_start_transaction(root: tree_root, num_items: 0); |
1170 | if (IS_ERR(ptr: trans)) |
1171 | return PTR_ERR(ptr: trans); |
1172 | |
1173 | set_bit(nr: BTRFS_FS_CREATING_FREE_SPACE_TREE, addr: &fs_info->flags); |
1174 | set_bit(nr: BTRFS_FS_FREE_SPACE_TREE_UNTRUSTED, addr: &fs_info->flags); |
1175 | free_space_root = btrfs_create_tree(trans, |
1176 | BTRFS_FREE_SPACE_TREE_OBJECTID); |
1177 | if (IS_ERR(ptr: free_space_root)) { |
1178 | ret = PTR_ERR(ptr: free_space_root); |
1179 | goto abort; |
1180 | } |
1181 | ret = btrfs_global_root_insert(root: free_space_root); |
1182 | if (ret) { |
1183 | btrfs_put_root(root: free_space_root); |
1184 | goto abort; |
1185 | } |
1186 | |
1187 | node = rb_first_cached(&fs_info->block_group_cache_tree); |
1188 | while (node) { |
1189 | block_group = rb_entry(node, struct btrfs_block_group, |
1190 | cache_node); |
1191 | ret = populate_free_space_tree(trans, block_group); |
1192 | if (ret) |
1193 | goto abort; |
1194 | node = rb_next(node); |
1195 | } |
1196 | |
1197 | btrfs_set_fs_compat_ro(fs_info, FREE_SPACE_TREE); |
1198 | btrfs_set_fs_compat_ro(fs_info, FREE_SPACE_TREE_VALID); |
1199 | clear_bit(nr: BTRFS_FS_CREATING_FREE_SPACE_TREE, addr: &fs_info->flags); |
1200 | ret = btrfs_commit_transaction(trans); |
1201 | |
1202 | /* |
1203 | * Now that we've committed the transaction any reading of our commit |
1204 | * root will be safe, so we can cache from the free space tree now. |
1205 | */ |
1206 | clear_bit(nr: BTRFS_FS_FREE_SPACE_TREE_UNTRUSTED, addr: &fs_info->flags); |
1207 | return ret; |
1208 | |
1209 | abort: |
1210 | clear_bit(nr: BTRFS_FS_CREATING_FREE_SPACE_TREE, addr: &fs_info->flags); |
1211 | clear_bit(nr: BTRFS_FS_FREE_SPACE_TREE_UNTRUSTED, addr: &fs_info->flags); |
1212 | btrfs_abort_transaction(trans, ret); |
1213 | btrfs_end_transaction(trans); |
1214 | return ret; |
1215 | } |
1216 | |
1217 | static int clear_free_space_tree(struct btrfs_trans_handle *trans, |
1218 | struct btrfs_root *root) |
1219 | { |
1220 | struct btrfs_path *path; |
1221 | struct btrfs_key key; |
1222 | int nr; |
1223 | int ret; |
1224 | |
1225 | path = btrfs_alloc_path(); |
1226 | if (!path) |
1227 | return -ENOMEM; |
1228 | |
1229 | key.objectid = 0; |
1230 | key.type = 0; |
1231 | key.offset = 0; |
1232 | |
1233 | while (1) { |
1234 | ret = btrfs_search_slot(trans, root, key: &key, p: path, ins_len: -1, cow: 1); |
1235 | if (ret < 0) |
1236 | goto out; |
1237 | |
1238 | nr = btrfs_header_nritems(eb: path->nodes[0]); |
1239 | if (!nr) |
1240 | break; |
1241 | |
1242 | path->slots[0] = 0; |
1243 | ret = btrfs_del_items(trans, root, path, slot: 0, nr); |
1244 | if (ret) |
1245 | goto out; |
1246 | |
1247 | btrfs_release_path(p: path); |
1248 | } |
1249 | |
1250 | ret = 0; |
1251 | out: |
1252 | btrfs_free_path(p: path); |
1253 | return ret; |
1254 | } |
1255 | |
1256 | int btrfs_delete_free_space_tree(struct btrfs_fs_info *fs_info) |
1257 | { |
1258 | struct btrfs_trans_handle *trans; |
1259 | struct btrfs_root *tree_root = fs_info->tree_root; |
1260 | struct btrfs_key key = { |
1261 | .objectid = BTRFS_FREE_SPACE_TREE_OBJECTID, |
1262 | .type = BTRFS_ROOT_ITEM_KEY, |
1263 | .offset = 0, |
1264 | }; |
1265 | struct btrfs_root *free_space_root = btrfs_global_root(fs_info, key: &key); |
1266 | int ret; |
1267 | |
1268 | trans = btrfs_start_transaction(root: tree_root, num_items: 0); |
1269 | if (IS_ERR(ptr: trans)) |
1270 | return PTR_ERR(ptr: trans); |
1271 | |
1272 | btrfs_clear_fs_compat_ro(fs_info, FREE_SPACE_TREE); |
1273 | btrfs_clear_fs_compat_ro(fs_info, FREE_SPACE_TREE_VALID); |
1274 | |
1275 | ret = clear_free_space_tree(trans, root: free_space_root); |
1276 | if (ret) |
1277 | goto abort; |
1278 | |
1279 | ret = btrfs_del_root(trans, key: &free_space_root->root_key); |
1280 | if (ret) |
1281 | goto abort; |
1282 | |
1283 | btrfs_global_root_delete(root: free_space_root); |
1284 | |
1285 | spin_lock(lock: &fs_info->trans_lock); |
1286 | list_del(entry: &free_space_root->dirty_list); |
1287 | spin_unlock(lock: &fs_info->trans_lock); |
1288 | |
1289 | btrfs_tree_lock(eb: free_space_root->node); |
1290 | btrfs_clear_buffer_dirty(trans, buf: free_space_root->node); |
1291 | btrfs_tree_unlock(eb: free_space_root->node); |
1292 | btrfs_free_tree_block(trans, root_id: btrfs_root_id(root: free_space_root), |
1293 | buf: free_space_root->node, parent: 0, last_ref: 1); |
1294 | |
1295 | btrfs_put_root(root: free_space_root); |
1296 | |
1297 | return btrfs_commit_transaction(trans); |
1298 | |
1299 | abort: |
1300 | btrfs_abort_transaction(trans, ret); |
1301 | btrfs_end_transaction(trans); |
1302 | return ret; |
1303 | } |
1304 | |
1305 | int btrfs_rebuild_free_space_tree(struct btrfs_fs_info *fs_info) |
1306 | { |
1307 | struct btrfs_trans_handle *trans; |
1308 | struct btrfs_key key = { |
1309 | .objectid = BTRFS_FREE_SPACE_TREE_OBJECTID, |
1310 | .type = BTRFS_ROOT_ITEM_KEY, |
1311 | .offset = 0, |
1312 | }; |
1313 | struct btrfs_root *free_space_root = btrfs_global_root(fs_info, key: &key); |
1314 | struct rb_node *node; |
1315 | int ret; |
1316 | |
1317 | trans = btrfs_start_transaction(root: free_space_root, num_items: 1); |
1318 | if (IS_ERR(ptr: trans)) |
1319 | return PTR_ERR(ptr: trans); |
1320 | |
1321 | set_bit(nr: BTRFS_FS_CREATING_FREE_SPACE_TREE, addr: &fs_info->flags); |
1322 | set_bit(nr: BTRFS_FS_FREE_SPACE_TREE_UNTRUSTED, addr: &fs_info->flags); |
1323 | |
1324 | ret = clear_free_space_tree(trans, root: free_space_root); |
1325 | if (ret) |
1326 | goto abort; |
1327 | |
1328 | node = rb_first_cached(&fs_info->block_group_cache_tree); |
1329 | while (node) { |
1330 | struct btrfs_block_group *block_group; |
1331 | |
1332 | block_group = rb_entry(node, struct btrfs_block_group, |
1333 | cache_node); |
1334 | ret = populate_free_space_tree(trans, block_group); |
1335 | if (ret) |
1336 | goto abort; |
1337 | node = rb_next(node); |
1338 | } |
1339 | |
1340 | btrfs_set_fs_compat_ro(fs_info, FREE_SPACE_TREE); |
1341 | btrfs_set_fs_compat_ro(fs_info, FREE_SPACE_TREE_VALID); |
1342 | clear_bit(nr: BTRFS_FS_CREATING_FREE_SPACE_TREE, addr: &fs_info->flags); |
1343 | |
1344 | ret = btrfs_commit_transaction(trans); |
1345 | clear_bit(nr: BTRFS_FS_FREE_SPACE_TREE_UNTRUSTED, addr: &fs_info->flags); |
1346 | return ret; |
1347 | abort: |
1348 | btrfs_abort_transaction(trans, ret); |
1349 | btrfs_end_transaction(trans); |
1350 | return ret; |
1351 | } |
1352 | |
1353 | static int __add_block_group_free_space(struct btrfs_trans_handle *trans, |
1354 | struct btrfs_block_group *block_group, |
1355 | struct btrfs_path *path) |
1356 | { |
1357 | int ret; |
1358 | |
1359 | clear_bit(nr: BLOCK_GROUP_FLAG_NEEDS_FREE_SPACE, addr: &block_group->runtime_flags); |
1360 | |
1361 | ret = add_new_free_space_info(trans, block_group, path); |
1362 | if (ret) |
1363 | return ret; |
1364 | |
1365 | return __add_to_free_space_tree(trans, block_group, path, |
1366 | start: block_group->start, |
1367 | size: block_group->length); |
1368 | } |
1369 | |
1370 | int add_block_group_free_space(struct btrfs_trans_handle *trans, |
1371 | struct btrfs_block_group *block_group) |
1372 | { |
1373 | struct btrfs_fs_info *fs_info = trans->fs_info; |
1374 | struct btrfs_path *path = NULL; |
1375 | int ret = 0; |
1376 | |
1377 | if (!btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE)) |
1378 | return 0; |
1379 | |
1380 | mutex_lock(&block_group->free_space_lock); |
1381 | if (!test_bit(BLOCK_GROUP_FLAG_NEEDS_FREE_SPACE, &block_group->runtime_flags)) |
1382 | goto out; |
1383 | |
1384 | path = btrfs_alloc_path(); |
1385 | if (!path) { |
1386 | ret = -ENOMEM; |
1387 | goto out; |
1388 | } |
1389 | |
1390 | ret = __add_block_group_free_space(trans, block_group, path); |
1391 | |
1392 | out: |
1393 | btrfs_free_path(p: path); |
1394 | mutex_unlock(lock: &block_group->free_space_lock); |
1395 | if (ret) |
1396 | btrfs_abort_transaction(trans, ret); |
1397 | return ret; |
1398 | } |
1399 | |
1400 | int remove_block_group_free_space(struct btrfs_trans_handle *trans, |
1401 | struct btrfs_block_group *block_group) |
1402 | { |
1403 | struct btrfs_root *root = btrfs_free_space_root(block_group); |
1404 | struct btrfs_path *path; |
1405 | struct btrfs_key key, found_key; |
1406 | struct extent_buffer *leaf; |
1407 | u64 start, end; |
1408 | int done = 0, nr; |
1409 | int ret; |
1410 | |
1411 | if (!btrfs_fs_compat_ro(trans->fs_info, FREE_SPACE_TREE)) |
1412 | return 0; |
1413 | |
1414 | if (test_bit(BLOCK_GROUP_FLAG_NEEDS_FREE_SPACE, &block_group->runtime_flags)) { |
1415 | /* We never added this block group to the free space tree. */ |
1416 | return 0; |
1417 | } |
1418 | |
1419 | path = btrfs_alloc_path(); |
1420 | if (!path) { |
1421 | ret = -ENOMEM; |
1422 | goto out; |
1423 | } |
1424 | |
1425 | start = block_group->start; |
1426 | end = block_group->start + block_group->length; |
1427 | |
1428 | key.objectid = end - 1; |
1429 | key.type = (u8)-1; |
1430 | key.offset = (u64)-1; |
1431 | |
1432 | while (!done) { |
1433 | ret = btrfs_search_prev_slot(trans, root, key: &key, p: path, ins_len: -1, cow: 1); |
1434 | if (ret) |
1435 | goto out; |
1436 | |
1437 | leaf = path->nodes[0]; |
1438 | nr = 0; |
1439 | path->slots[0]++; |
1440 | while (path->slots[0] > 0) { |
1441 | btrfs_item_key_to_cpu(eb: leaf, cpu_key: &found_key, nr: path->slots[0] - 1); |
1442 | |
1443 | if (found_key.type == BTRFS_FREE_SPACE_INFO_KEY) { |
1444 | ASSERT(found_key.objectid == block_group->start); |
1445 | ASSERT(found_key.offset == block_group->length); |
1446 | done = 1; |
1447 | nr++; |
1448 | path->slots[0]--; |
1449 | break; |
1450 | } else if (found_key.type == BTRFS_FREE_SPACE_EXTENT_KEY || |
1451 | found_key.type == BTRFS_FREE_SPACE_BITMAP_KEY) { |
1452 | ASSERT(found_key.objectid >= start); |
1453 | ASSERT(found_key.objectid < end); |
1454 | ASSERT(found_key.objectid + found_key.offset <= end); |
1455 | nr++; |
1456 | path->slots[0]--; |
1457 | } else { |
1458 | ASSERT(0); |
1459 | } |
1460 | } |
1461 | |
1462 | ret = btrfs_del_items(trans, root, path, slot: path->slots[0], nr); |
1463 | if (ret) |
1464 | goto out; |
1465 | btrfs_release_path(p: path); |
1466 | } |
1467 | |
1468 | ret = 0; |
1469 | out: |
1470 | btrfs_free_path(p: path); |
1471 | if (ret) |
1472 | btrfs_abort_transaction(trans, ret); |
1473 | return ret; |
1474 | } |
1475 | |
1476 | static int load_free_space_bitmaps(struct btrfs_caching_control *caching_ctl, |
1477 | struct btrfs_path *path, |
1478 | u32 expected_extent_count) |
1479 | { |
1480 | struct btrfs_block_group *block_group; |
1481 | struct btrfs_fs_info *fs_info; |
1482 | struct btrfs_root *root; |
1483 | struct btrfs_key key; |
1484 | int prev_bit = 0, bit; |
1485 | /* Initialize to silence GCC. */ |
1486 | u64 extent_start = 0; |
1487 | u64 end, offset; |
1488 | u64 total_found = 0; |
1489 | u32 extent_count = 0; |
1490 | int ret; |
1491 | |
1492 | block_group = caching_ctl->block_group; |
1493 | fs_info = block_group->fs_info; |
1494 | root = btrfs_free_space_root(block_group); |
1495 | |
1496 | end = block_group->start + block_group->length; |
1497 | |
1498 | while (1) { |
1499 | ret = btrfs_next_item(root, p: path); |
1500 | if (ret < 0) |
1501 | goto out; |
1502 | if (ret) |
1503 | break; |
1504 | |
1505 | btrfs_item_key_to_cpu(eb: path->nodes[0], cpu_key: &key, nr: path->slots[0]); |
1506 | |
1507 | if (key.type == BTRFS_FREE_SPACE_INFO_KEY) |
1508 | break; |
1509 | |
1510 | ASSERT(key.type == BTRFS_FREE_SPACE_BITMAP_KEY); |
1511 | ASSERT(key.objectid < end && key.objectid + key.offset <= end); |
1512 | |
1513 | offset = key.objectid; |
1514 | while (offset < key.objectid + key.offset) { |
1515 | bit = free_space_test_bit(block_group, path, offset); |
1516 | if (prev_bit == 0 && bit == 1) { |
1517 | extent_start = offset; |
1518 | } else if (prev_bit == 1 && bit == 0) { |
1519 | u64 space_added; |
1520 | |
1521 | ret = btrfs_add_new_free_space(block_group, |
1522 | start: extent_start, |
1523 | end: offset, |
1524 | total_added_ret: &space_added); |
1525 | if (ret) |
1526 | goto out; |
1527 | total_found += space_added; |
1528 | if (total_found > CACHING_CTL_WAKE_UP) { |
1529 | total_found = 0; |
1530 | wake_up(&caching_ctl->wait); |
1531 | } |
1532 | extent_count++; |
1533 | } |
1534 | prev_bit = bit; |
1535 | offset += fs_info->sectorsize; |
1536 | } |
1537 | } |
1538 | if (prev_bit == 1) { |
1539 | ret = btrfs_add_new_free_space(block_group, start: extent_start, end, NULL); |
1540 | if (ret) |
1541 | goto out; |
1542 | extent_count++; |
1543 | } |
1544 | |
1545 | if (extent_count != expected_extent_count) { |
1546 | btrfs_err(fs_info, |
1547 | "incorrect extent count for %llu; counted %u, expected %u" , |
1548 | block_group->start, extent_count, |
1549 | expected_extent_count); |
1550 | ASSERT(0); |
1551 | ret = -EIO; |
1552 | goto out; |
1553 | } |
1554 | |
1555 | ret = 0; |
1556 | out: |
1557 | return ret; |
1558 | } |
1559 | |
1560 | static int load_free_space_extents(struct btrfs_caching_control *caching_ctl, |
1561 | struct btrfs_path *path, |
1562 | u32 expected_extent_count) |
1563 | { |
1564 | struct btrfs_block_group *block_group; |
1565 | struct btrfs_fs_info *fs_info; |
1566 | struct btrfs_root *root; |
1567 | struct btrfs_key key; |
1568 | u64 end; |
1569 | u64 total_found = 0; |
1570 | u32 extent_count = 0; |
1571 | int ret; |
1572 | |
1573 | block_group = caching_ctl->block_group; |
1574 | fs_info = block_group->fs_info; |
1575 | root = btrfs_free_space_root(block_group); |
1576 | |
1577 | end = block_group->start + block_group->length; |
1578 | |
1579 | while (1) { |
1580 | u64 space_added; |
1581 | |
1582 | ret = btrfs_next_item(root, p: path); |
1583 | if (ret < 0) |
1584 | goto out; |
1585 | if (ret) |
1586 | break; |
1587 | |
1588 | btrfs_item_key_to_cpu(eb: path->nodes[0], cpu_key: &key, nr: path->slots[0]); |
1589 | |
1590 | if (key.type == BTRFS_FREE_SPACE_INFO_KEY) |
1591 | break; |
1592 | |
1593 | ASSERT(key.type == BTRFS_FREE_SPACE_EXTENT_KEY); |
1594 | ASSERT(key.objectid < end && key.objectid + key.offset <= end); |
1595 | |
1596 | ret = btrfs_add_new_free_space(block_group, start: key.objectid, |
1597 | end: key.objectid + key.offset, |
1598 | total_added_ret: &space_added); |
1599 | if (ret) |
1600 | goto out; |
1601 | total_found += space_added; |
1602 | if (total_found > CACHING_CTL_WAKE_UP) { |
1603 | total_found = 0; |
1604 | wake_up(&caching_ctl->wait); |
1605 | } |
1606 | extent_count++; |
1607 | } |
1608 | |
1609 | if (extent_count != expected_extent_count) { |
1610 | btrfs_err(fs_info, |
1611 | "incorrect extent count for %llu; counted %u, expected %u" , |
1612 | block_group->start, extent_count, |
1613 | expected_extent_count); |
1614 | ASSERT(0); |
1615 | ret = -EIO; |
1616 | goto out; |
1617 | } |
1618 | |
1619 | ret = 0; |
1620 | out: |
1621 | return ret; |
1622 | } |
1623 | |
1624 | int load_free_space_tree(struct btrfs_caching_control *caching_ctl) |
1625 | { |
1626 | struct btrfs_block_group *block_group; |
1627 | struct btrfs_free_space_info *info; |
1628 | struct btrfs_path *path; |
1629 | u32 extent_count, flags; |
1630 | int ret; |
1631 | |
1632 | block_group = caching_ctl->block_group; |
1633 | |
1634 | path = btrfs_alloc_path(); |
1635 | if (!path) |
1636 | return -ENOMEM; |
1637 | |
1638 | /* |
1639 | * Just like caching_thread() doesn't want to deadlock on the extent |
1640 | * tree, we don't want to deadlock on the free space tree. |
1641 | */ |
1642 | path->skip_locking = 1; |
1643 | path->search_commit_root = 1; |
1644 | path->reada = READA_FORWARD; |
1645 | |
1646 | info = search_free_space_info(NULL, block_group, path, cow: 0); |
1647 | if (IS_ERR(ptr: info)) { |
1648 | ret = PTR_ERR(ptr: info); |
1649 | goto out; |
1650 | } |
1651 | extent_count = btrfs_free_space_extent_count(eb: path->nodes[0], s: info); |
1652 | flags = btrfs_free_space_flags(eb: path->nodes[0], s: info); |
1653 | |
1654 | /* |
1655 | * We left path pointing to the free space info item, so now |
1656 | * load_free_space_foo can just iterate through the free space tree from |
1657 | * there. |
1658 | */ |
1659 | if (flags & BTRFS_FREE_SPACE_USING_BITMAPS) |
1660 | ret = load_free_space_bitmaps(caching_ctl, path, expected_extent_count: extent_count); |
1661 | else |
1662 | ret = load_free_space_extents(caching_ctl, path, expected_extent_count: extent_count); |
1663 | |
1664 | out: |
1665 | btrfs_free_path(p: path); |
1666 | return ret; |
1667 | } |
1668 | |