1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Copyright (C) 2007 Oracle. All rights reserved.
4 */
5
6 #include <linux/kthread.h>
7 #include <linux/pagemap.h>
8
9 #include "ctree.h"
10 #include "disk-io.h"
11 #include "free-space-cache.h"
12 #include "inode-map.h"
13 #include "transaction.h"
14 #include "delalloc-space.h"
15
fail_caching_thread(struct btrfs_root * root)16 static void fail_caching_thread(struct btrfs_root *root)
17 {
18 struct btrfs_fs_info *fs_info = root->fs_info;
19
20 btrfs_warn(fs_info, "failed to start inode caching task");
21 btrfs_clear_pending_and_info(fs_info, INODE_MAP_CACHE,
22 "disabling inode map caching");
23 spin_lock(&root->ino_cache_lock);
24 root->ino_cache_state = BTRFS_CACHE_ERROR;
25 spin_unlock(&root->ino_cache_lock);
26 wake_up(&root->ino_cache_wait);
27 }
28
caching_kthread(void * data)29 static int caching_kthread(void *data)
30 {
31 struct btrfs_root *root = data;
32 struct btrfs_fs_info *fs_info = root->fs_info;
33 struct btrfs_free_space_ctl *ctl = root->free_ino_ctl;
34 struct btrfs_key key;
35 struct btrfs_path *path;
36 struct extent_buffer *leaf;
37 u64 last = (u64)-1;
38 int slot;
39 int ret;
40
41 if (!btrfs_test_opt(fs_info, INODE_MAP_CACHE))
42 return 0;
43
44 path = btrfs_alloc_path();
45 if (!path) {
46 fail_caching_thread(root);
47 return -ENOMEM;
48 }
49
50 /* Since the commit root is read-only, we can safely skip locking. */
51 path->skip_locking = 1;
52 path->search_commit_root = 1;
53 path->reada = READA_FORWARD;
54
55 key.objectid = BTRFS_FIRST_FREE_OBJECTID;
56 key.offset = 0;
57 key.type = BTRFS_INODE_ITEM_KEY;
58 again:
59 /* need to make sure the commit_root doesn't disappear */
60 down_read(&fs_info->commit_root_sem);
61
62 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
63 if (ret < 0)
64 goto out;
65
66 while (1) {
67 if (btrfs_fs_closing(fs_info))
68 goto out;
69
70 leaf = path->nodes[0];
71 slot = path->slots[0];
72 if (slot >= btrfs_header_nritems(leaf)) {
73 ret = btrfs_next_leaf(root, path);
74 if (ret < 0)
75 goto out;
76 else if (ret > 0)
77 break;
78
79 if (need_resched() ||
80 btrfs_transaction_in_commit(fs_info)) {
81 leaf = path->nodes[0];
82
83 if (WARN_ON(btrfs_header_nritems(leaf) == 0))
84 break;
85
86 /*
87 * Save the key so we can advances forward
88 * in the next search.
89 */
90 btrfs_item_key_to_cpu(leaf, &key, 0);
91 btrfs_release_path(path);
92 root->ino_cache_progress = last;
93 up_read(&fs_info->commit_root_sem);
94 schedule_timeout(1);
95 goto again;
96 } else
97 continue;
98 }
99
100 btrfs_item_key_to_cpu(leaf, &key, slot);
101
102 if (key.type != BTRFS_INODE_ITEM_KEY)
103 goto next;
104
105 if (key.objectid >= root->highest_objectid)
106 break;
107
108 if (last != (u64)-1 && last + 1 != key.objectid) {
109 __btrfs_add_free_space(fs_info, ctl, last + 1,
110 key.objectid - last - 1);
111 wake_up(&root->ino_cache_wait);
112 }
113
114 last = key.objectid;
115 next:
116 path->slots[0]++;
117 }
118
119 if (last < root->highest_objectid - 1) {
120 __btrfs_add_free_space(fs_info, ctl, last + 1,
121 root->highest_objectid - last - 1);
122 }
123
124 spin_lock(&root->ino_cache_lock);
125 root->ino_cache_state = BTRFS_CACHE_FINISHED;
126 spin_unlock(&root->ino_cache_lock);
127
128 root->ino_cache_progress = (u64)-1;
129 btrfs_unpin_free_ino(root);
130 out:
131 wake_up(&root->ino_cache_wait);
132 up_read(&fs_info->commit_root_sem);
133
134 btrfs_free_path(path);
135
136 return ret;
137 }
138
start_caching(struct btrfs_root * root)139 static void start_caching(struct btrfs_root *root)
140 {
141 struct btrfs_fs_info *fs_info = root->fs_info;
142 struct btrfs_free_space_ctl *ctl = root->free_ino_ctl;
143 struct task_struct *tsk;
144 int ret;
145 u64 objectid;
146
147 if (!btrfs_test_opt(fs_info, INODE_MAP_CACHE))
148 return;
149
150 spin_lock(&root->ino_cache_lock);
151 if (root->ino_cache_state != BTRFS_CACHE_NO) {
152 spin_unlock(&root->ino_cache_lock);
153 return;
154 }
155
156 root->ino_cache_state = BTRFS_CACHE_STARTED;
157 spin_unlock(&root->ino_cache_lock);
158
159 ret = load_free_ino_cache(fs_info, root);
160 if (ret == 1) {
161 spin_lock(&root->ino_cache_lock);
162 root->ino_cache_state = BTRFS_CACHE_FINISHED;
163 spin_unlock(&root->ino_cache_lock);
164 wake_up(&root->ino_cache_wait);
165 return;
166 }
167
168 /*
169 * It can be quite time-consuming to fill the cache by searching
170 * through the extent tree, and this can keep ino allocation path
171 * waiting. Therefore at start we quickly find out the highest
172 * inode number and we know we can use inode numbers which fall in
173 * [highest_ino + 1, BTRFS_LAST_FREE_OBJECTID].
174 */
175 ret = btrfs_find_free_objectid(root, &objectid);
176 if (!ret && objectid <= BTRFS_LAST_FREE_OBJECTID) {
177 __btrfs_add_free_space(fs_info, ctl, objectid,
178 BTRFS_LAST_FREE_OBJECTID - objectid + 1);
179 wake_up(&root->ino_cache_wait);
180 }
181
182 tsk = kthread_run(caching_kthread, root, "btrfs-ino-cache-%llu",
183 root->root_key.objectid);
184 if (IS_ERR(tsk))
185 fail_caching_thread(root);
186 }
187
btrfs_find_free_ino(struct btrfs_root * root,u64 * objectid)188 int btrfs_find_free_ino(struct btrfs_root *root, u64 *objectid)
189 {
190 if (!btrfs_test_opt(root->fs_info, INODE_MAP_CACHE))
191 return btrfs_find_free_objectid(root, objectid);
192
193 again:
194 *objectid = btrfs_find_ino_for_alloc(root);
195
196 if (*objectid != 0)
197 return 0;
198
199 start_caching(root);
200
201 wait_event(root->ino_cache_wait,
202 root->ino_cache_state == BTRFS_CACHE_FINISHED ||
203 root->ino_cache_state == BTRFS_CACHE_ERROR ||
204 root->free_ino_ctl->free_space > 0);
205
206 if (root->ino_cache_state == BTRFS_CACHE_FINISHED &&
207 root->free_ino_ctl->free_space == 0)
208 return -ENOSPC;
209 else if (root->ino_cache_state == BTRFS_CACHE_ERROR)
210 return btrfs_find_free_objectid(root, objectid);
211 else
212 goto again;
213 }
214
btrfs_return_ino(struct btrfs_root * root,u64 objectid)215 void btrfs_return_ino(struct btrfs_root *root, u64 objectid)
216 {
217 struct btrfs_fs_info *fs_info = root->fs_info;
218 struct btrfs_free_space_ctl *pinned = root->free_ino_pinned;
219
220 if (!btrfs_test_opt(fs_info, INODE_MAP_CACHE))
221 return;
222 again:
223 if (root->ino_cache_state == BTRFS_CACHE_FINISHED) {
224 __btrfs_add_free_space(fs_info, pinned, objectid, 1);
225 } else {
226 down_write(&fs_info->commit_root_sem);
227 spin_lock(&root->ino_cache_lock);
228 if (root->ino_cache_state == BTRFS_CACHE_FINISHED) {
229 spin_unlock(&root->ino_cache_lock);
230 up_write(&fs_info->commit_root_sem);
231 goto again;
232 }
233 spin_unlock(&root->ino_cache_lock);
234
235 start_caching(root);
236
237 __btrfs_add_free_space(fs_info, pinned, objectid, 1);
238
239 up_write(&fs_info->commit_root_sem);
240 }
241 }
242
243 /*
244 * When a transaction is committed, we'll move those inode numbers which are
245 * smaller than root->ino_cache_progress from pinned tree to free_ino tree, and
246 * others will just be dropped, because the commit root we were searching has
247 * changed.
248 *
249 * Must be called with root->fs_info->commit_root_sem held
250 */
btrfs_unpin_free_ino(struct btrfs_root * root)251 void btrfs_unpin_free_ino(struct btrfs_root *root)
252 {
253 struct btrfs_free_space_ctl *ctl = root->free_ino_ctl;
254 struct rb_root *rbroot = &root->free_ino_pinned->free_space_offset;
255 spinlock_t *rbroot_lock = &root->free_ino_pinned->tree_lock;
256 struct btrfs_free_space *info;
257 struct rb_node *n;
258 u64 count;
259
260 if (!btrfs_test_opt(root->fs_info, INODE_MAP_CACHE))
261 return;
262
263 while (1) {
264 spin_lock(rbroot_lock);
265 n = rb_first(rbroot);
266 if (!n) {
267 spin_unlock(rbroot_lock);
268 break;
269 }
270
271 info = rb_entry(n, struct btrfs_free_space, offset_index);
272 BUG_ON(info->bitmap); /* Logic error */
273
274 if (info->offset > root->ino_cache_progress)
275 count = 0;
276 else
277 count = min(root->ino_cache_progress - info->offset + 1,
278 info->bytes);
279
280 rb_erase(&info->offset_index, rbroot);
281 spin_unlock(rbroot_lock);
282 if (count)
283 __btrfs_add_free_space(root->fs_info, ctl,
284 info->offset, count);
285 kmem_cache_free(btrfs_free_space_cachep, info);
286 }
287 }
288
289 #define INIT_THRESHOLD ((SZ_32K / 2) / sizeof(struct btrfs_free_space))
290 #define INODES_PER_BITMAP (PAGE_SIZE * 8)
291
292 /*
293 * The goal is to keep the memory used by the free_ino tree won't
294 * exceed the memory if we use bitmaps only.
295 */
recalculate_thresholds(struct btrfs_free_space_ctl * ctl)296 static void recalculate_thresholds(struct btrfs_free_space_ctl *ctl)
297 {
298 struct btrfs_free_space *info;
299 struct rb_node *n;
300 int max_ino;
301 int max_bitmaps;
302
303 n = rb_last(&ctl->free_space_offset);
304 if (!n) {
305 ctl->extents_thresh = INIT_THRESHOLD;
306 return;
307 }
308 info = rb_entry(n, struct btrfs_free_space, offset_index);
309
310 /*
311 * Find the maximum inode number in the filesystem. Note we
312 * ignore the fact that this can be a bitmap, because we are
313 * not doing precise calculation.
314 */
315 max_ino = info->bytes - 1;
316
317 max_bitmaps = ALIGN(max_ino, INODES_PER_BITMAP) / INODES_PER_BITMAP;
318 if (max_bitmaps <= ctl->total_bitmaps) {
319 ctl->extents_thresh = 0;
320 return;
321 }
322
323 ctl->extents_thresh = (max_bitmaps - ctl->total_bitmaps) *
324 PAGE_SIZE / sizeof(*info);
325 }
326
327 /*
328 * We don't fall back to bitmap, if we are below the extents threshold
329 * or this chunk of inode numbers is a big one.
330 */
use_bitmap(struct btrfs_free_space_ctl * ctl,struct btrfs_free_space * info)331 static bool use_bitmap(struct btrfs_free_space_ctl *ctl,
332 struct btrfs_free_space *info)
333 {
334 if (ctl->free_extents < ctl->extents_thresh ||
335 info->bytes > INODES_PER_BITMAP / 10)
336 return false;
337
338 return true;
339 }
340
341 static const struct btrfs_free_space_op free_ino_op = {
342 .recalc_thresholds = recalculate_thresholds,
343 .use_bitmap = use_bitmap,
344 };
345
pinned_recalc_thresholds(struct btrfs_free_space_ctl * ctl)346 static void pinned_recalc_thresholds(struct btrfs_free_space_ctl *ctl)
347 {
348 }
349
pinned_use_bitmap(struct btrfs_free_space_ctl * ctl,struct btrfs_free_space * info)350 static bool pinned_use_bitmap(struct btrfs_free_space_ctl *ctl,
351 struct btrfs_free_space *info)
352 {
353 /*
354 * We always use extents for two reasons:
355 *
356 * - The pinned tree is only used during the process of caching
357 * work.
358 * - Make code simpler. See btrfs_unpin_free_ino().
359 */
360 return false;
361 }
362
363 static const struct btrfs_free_space_op pinned_free_ino_op = {
364 .recalc_thresholds = pinned_recalc_thresholds,
365 .use_bitmap = pinned_use_bitmap,
366 };
367
btrfs_init_free_ino_ctl(struct btrfs_root * root)368 void btrfs_init_free_ino_ctl(struct btrfs_root *root)
369 {
370 struct btrfs_free_space_ctl *ctl = root->free_ino_ctl;
371 struct btrfs_free_space_ctl *pinned = root->free_ino_pinned;
372
373 spin_lock_init(&ctl->tree_lock);
374 ctl->unit = 1;
375 ctl->start = 0;
376 ctl->private = NULL;
377 ctl->op = &free_ino_op;
378 INIT_LIST_HEAD(&ctl->trimming_ranges);
379 mutex_init(&ctl->cache_writeout_mutex);
380
381 /*
382 * Initially we allow to use 16K of ram to cache chunks of
383 * inode numbers before we resort to bitmaps. This is somewhat
384 * arbitrary, but it will be adjusted in runtime.
385 */
386 ctl->extents_thresh = INIT_THRESHOLD;
387
388 spin_lock_init(&pinned->tree_lock);
389 pinned->unit = 1;
390 pinned->start = 0;
391 pinned->private = NULL;
392 pinned->extents_thresh = 0;
393 pinned->op = &pinned_free_ino_op;
394 }
395
btrfs_save_ino_cache(struct btrfs_root * root,struct btrfs_trans_handle * trans)396 int btrfs_save_ino_cache(struct btrfs_root *root,
397 struct btrfs_trans_handle *trans)
398 {
399 struct btrfs_fs_info *fs_info = root->fs_info;
400 struct btrfs_free_space_ctl *ctl = root->free_ino_ctl;
401 struct btrfs_path *path;
402 struct inode *inode;
403 struct btrfs_block_rsv *rsv;
404 struct extent_changeset *data_reserved = NULL;
405 u64 num_bytes;
406 u64 alloc_hint = 0;
407 int ret;
408 int prealloc;
409 bool retry = false;
410
411 /* only fs tree and subvol/snap needs ino cache */
412 if (root->root_key.objectid != BTRFS_FS_TREE_OBJECTID &&
413 (root->root_key.objectid < BTRFS_FIRST_FREE_OBJECTID ||
414 root->root_key.objectid > BTRFS_LAST_FREE_OBJECTID))
415 return 0;
416
417 /* Don't save inode cache if we are deleting this root */
418 if (btrfs_root_refs(&root->root_item) == 0)
419 return 0;
420
421 if (!btrfs_test_opt(fs_info, INODE_MAP_CACHE))
422 return 0;
423
424 path = btrfs_alloc_path();
425 if (!path)
426 return -ENOMEM;
427
428 rsv = trans->block_rsv;
429 trans->block_rsv = &fs_info->trans_block_rsv;
430
431 num_bytes = trans->bytes_reserved;
432 /*
433 * 1 item for inode item insertion if need
434 * 4 items for inode item update (in the worst case)
435 * 1 items for slack space if we need do truncation
436 * 1 item for free space object
437 * 3 items for pre-allocation
438 */
439 trans->bytes_reserved = btrfs_calc_insert_metadata_size(fs_info, 10);
440 ret = btrfs_block_rsv_add(root, trans->block_rsv,
441 trans->bytes_reserved,
442 BTRFS_RESERVE_NO_FLUSH);
443 if (ret)
444 goto out;
445 trace_btrfs_space_reservation(fs_info, "ino_cache", trans->transid,
446 trans->bytes_reserved, 1);
447 again:
448 inode = lookup_free_ino_inode(root, path);
449 if (IS_ERR(inode) && (PTR_ERR(inode) != -ENOENT || retry)) {
450 ret = PTR_ERR(inode);
451 goto out_release;
452 }
453
454 if (IS_ERR(inode)) {
455 BUG_ON(retry); /* Logic error */
456 retry = true;
457
458 ret = create_free_ino_inode(root, trans, path);
459 if (ret)
460 goto out_release;
461 goto again;
462 }
463
464 BTRFS_I(inode)->generation = 0;
465 ret = btrfs_update_inode(trans, root, inode);
466 if (ret) {
467 btrfs_abort_transaction(trans, ret);
468 goto out_put;
469 }
470
471 if (i_size_read(inode) > 0) {
472 ret = btrfs_truncate_free_space_cache(trans, NULL, inode);
473 if (ret) {
474 if (ret != -ENOSPC)
475 btrfs_abort_transaction(trans, ret);
476 goto out_put;
477 }
478 }
479
480 spin_lock(&root->ino_cache_lock);
481 if (root->ino_cache_state != BTRFS_CACHE_FINISHED) {
482 ret = -1;
483 spin_unlock(&root->ino_cache_lock);
484 goto out_put;
485 }
486 spin_unlock(&root->ino_cache_lock);
487
488 spin_lock(&ctl->tree_lock);
489 prealloc = sizeof(struct btrfs_free_space) * ctl->free_extents;
490 prealloc = ALIGN(prealloc, PAGE_SIZE);
491 prealloc += ctl->total_bitmaps * PAGE_SIZE;
492 spin_unlock(&ctl->tree_lock);
493
494 /* Just to make sure we have enough space */
495 prealloc += 8 * PAGE_SIZE;
496
497 ret = btrfs_delalloc_reserve_space(inode, &data_reserved, 0, prealloc);
498 if (ret)
499 goto out_put;
500
501 ret = btrfs_prealloc_file_range_trans(inode, trans, 0, 0, prealloc,
502 prealloc, prealloc, &alloc_hint);
503 if (ret) {
504 btrfs_delalloc_release_extents(BTRFS_I(inode), prealloc);
505 btrfs_delalloc_release_metadata(BTRFS_I(inode), prealloc, true);
506 goto out_put;
507 }
508
509 ret = btrfs_write_out_ino_cache(root, trans, path, inode);
510 btrfs_delalloc_release_extents(BTRFS_I(inode), prealloc);
511 out_put:
512 iput(inode);
513 out_release:
514 trace_btrfs_space_reservation(fs_info, "ino_cache", trans->transid,
515 trans->bytes_reserved, 0);
516 btrfs_block_rsv_release(fs_info, trans->block_rsv,
517 trans->bytes_reserved);
518 out:
519 trans->block_rsv = rsv;
520 trans->bytes_reserved = num_bytes;
521
522 btrfs_free_path(path);
523 extent_changeset_free(data_reserved);
524 return ret;
525 }
526
btrfs_find_highest_objectid(struct btrfs_root * root,u64 * objectid)527 int btrfs_find_highest_objectid(struct btrfs_root *root, u64 *objectid)
528 {
529 struct btrfs_path *path;
530 int ret;
531 struct extent_buffer *l;
532 struct btrfs_key search_key;
533 struct btrfs_key found_key;
534 int slot;
535
536 path = btrfs_alloc_path();
537 if (!path)
538 return -ENOMEM;
539
540 search_key.objectid = BTRFS_LAST_FREE_OBJECTID;
541 search_key.type = -1;
542 search_key.offset = (u64)-1;
543 ret = btrfs_search_slot(NULL, root, &search_key, path, 0, 0);
544 if (ret < 0)
545 goto error;
546 BUG_ON(ret == 0); /* Corruption */
547 if (path->slots[0] > 0) {
548 slot = path->slots[0] - 1;
549 l = path->nodes[0];
550 btrfs_item_key_to_cpu(l, &found_key, slot);
551 *objectid = max_t(u64, found_key.objectid,
552 BTRFS_FIRST_FREE_OBJECTID - 1);
553 } else {
554 *objectid = BTRFS_FIRST_FREE_OBJECTID - 1;
555 }
556 ret = 0;
557 error:
558 btrfs_free_path(path);
559 return ret;
560 }
561
btrfs_find_free_objectid(struct btrfs_root * root,u64 * objectid)562 int btrfs_find_free_objectid(struct btrfs_root *root, u64 *objectid)
563 {
564 int ret;
565 mutex_lock(&root->objectid_mutex);
566
567 if (unlikely(root->highest_objectid >= BTRFS_LAST_FREE_OBJECTID)) {
568 btrfs_warn(root->fs_info,
569 "the objectid of root %llu reaches its highest value",
570 root->root_key.objectid);
571 ret = -ENOSPC;
572 goto out;
573 }
574
575 *objectid = ++root->highest_objectid;
576 ret = 0;
577 out:
578 mutex_unlock(&root->objectid_mutex);
579 return ret;
580 }
581