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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
16static 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
29static 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;
58again:
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, 0);
111 wake_up(&root->ino_cache_wait);
112 }
113
114 last = key.objectid;
115next:
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, 0);
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);
130out:
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
139static 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 0);
180 wake_up(&root->ino_cache_wait);
181 }
182
183 tsk = kthread_run(caching_kthread, root, "btrfs-ino-cache-%llu",
184 root->root_key.objectid);
185 if (IS_ERR(tsk))
186 fail_caching_thread(root);
187}
188
189int btrfs_find_free_ino(struct btrfs_root *root, u64 *objectid)
190{
191 if (!btrfs_test_opt(root->fs_info, INODE_MAP_CACHE))
192 return btrfs_find_free_objectid(root, objectid);
193
194again:
195 *objectid = btrfs_find_ino_for_alloc(root);
196
197 if (*objectid != 0)
198 return 0;
199
200 start_caching(root);
201
202 wait_event(root->ino_cache_wait,
203 root->ino_cache_state == BTRFS_CACHE_FINISHED ||
204 root->ino_cache_state == BTRFS_CACHE_ERROR ||
205 root->free_ino_ctl->free_space > 0);
206
207 if (root->ino_cache_state == BTRFS_CACHE_FINISHED &&
208 root->free_ino_ctl->free_space == 0)
209 return -ENOSPC;
210 else if (root->ino_cache_state == BTRFS_CACHE_ERROR)
211 return btrfs_find_free_objectid(root, objectid);
212 else
213 goto again;
214}
215
216void btrfs_return_ino(struct btrfs_root *root, u64 objectid)
217{
218 struct btrfs_fs_info *fs_info = root->fs_info;
219 struct btrfs_free_space_ctl *pinned = root->free_ino_pinned;
220
221 if (!btrfs_test_opt(fs_info, INODE_MAP_CACHE))
222 return;
223again:
224 if (root->ino_cache_state == BTRFS_CACHE_FINISHED) {
225 __btrfs_add_free_space(fs_info, pinned, objectid, 1, 0);
226 } else {
227 down_write(&fs_info->commit_root_sem);
228 spin_lock(&root->ino_cache_lock);
229 if (root->ino_cache_state == BTRFS_CACHE_FINISHED) {
230 spin_unlock(&root->ino_cache_lock);
231 up_write(&fs_info->commit_root_sem);
232 goto again;
233 }
234 spin_unlock(&root->ino_cache_lock);
235
236 start_caching(root);
237
238 __btrfs_add_free_space(fs_info, pinned, objectid, 1, 0);
239
240 up_write(&fs_info->commit_root_sem);
241 }
242}
243
244/*
245 * When a transaction is committed, we'll move those inode numbers which are
246 * smaller than root->ino_cache_progress from pinned tree to free_ino tree, and
247 * others will just be dropped, because the commit root we were searching has
248 * changed.
249 *
250 * Must be called with root->fs_info->commit_root_sem held
251 */
252void btrfs_unpin_free_ino(struct btrfs_root *root)
253{
254 struct btrfs_free_space_ctl *ctl = root->free_ino_ctl;
255 struct rb_root *rbroot = &root->free_ino_pinned->free_space_offset;
256 spinlock_t *rbroot_lock = &root->free_ino_pinned->tree_lock;
257 struct btrfs_free_space *info;
258 struct rb_node *n;
259 u64 count;
260
261 if (!btrfs_test_opt(root->fs_info, INODE_MAP_CACHE))
262 return;
263
264 while (1) {
265 spin_lock(rbroot_lock);
266 n = rb_first(rbroot);
267 if (!n) {
268 spin_unlock(rbroot_lock);
269 break;
270 }
271
272 info = rb_entry(n, struct btrfs_free_space, offset_index);
273 BUG_ON(info->bitmap); /* Logic error */
274
275 if (info->offset > root->ino_cache_progress)
276 count = 0;
277 else
278 count = min(root->ino_cache_progress - info->offset + 1,
279 info->bytes);
280
281 rb_erase(&info->offset_index, rbroot);
282 spin_unlock(rbroot_lock);
283 if (count)
284 __btrfs_add_free_space(root->fs_info, ctl,
285 info->offset, count, 0);
286 kmem_cache_free(btrfs_free_space_cachep, info);
287 }
288}
289
290#define INIT_THRESHOLD ((SZ_32K / 2) / sizeof(struct btrfs_free_space))
291#define INODES_PER_BITMAP (PAGE_SIZE * 8)
292
293/*
294 * The goal is to keep the memory used by the free_ino tree won't
295 * exceed the memory if we use bitmaps only.
296 */
297static void recalculate_thresholds(struct btrfs_free_space_ctl *ctl)
298{
299 struct btrfs_free_space *info;
300 struct rb_node *n;
301 int max_ino;
302 int max_bitmaps;
303
304 n = rb_last(&ctl->free_space_offset);
305 if (!n) {
306 ctl->extents_thresh = INIT_THRESHOLD;
307 return;
308 }
309 info = rb_entry(n, struct btrfs_free_space, offset_index);
310
311 /*
312 * Find the maximum inode number in the filesystem. Note we
313 * ignore the fact that this can be a bitmap, because we are
314 * not doing precise calculation.
315 */
316 max_ino = info->bytes - 1;
317
318 max_bitmaps = ALIGN(max_ino, INODES_PER_BITMAP) / INODES_PER_BITMAP;
319 if (max_bitmaps <= ctl->total_bitmaps) {
320 ctl->extents_thresh = 0;
321 return;
322 }
323
324 ctl->extents_thresh = (max_bitmaps - ctl->total_bitmaps) *
325 PAGE_SIZE / sizeof(*info);
326}
327
328/*
329 * We don't fall back to bitmap, if we are below the extents threshold
330 * or this chunk of inode numbers is a big one.
331 */
332static bool use_bitmap(struct btrfs_free_space_ctl *ctl,
333 struct btrfs_free_space *info)
334{
335 if (ctl->free_extents < ctl->extents_thresh ||
336 info->bytes > INODES_PER_BITMAP / 10)
337 return false;
338
339 return true;
340}
341
342static const struct btrfs_free_space_op free_ino_op = {
343 .recalc_thresholds = recalculate_thresholds,
344 .use_bitmap = use_bitmap,
345};
346
347static void pinned_recalc_thresholds(struct btrfs_free_space_ctl *ctl)
348{
349}
350
351static bool pinned_use_bitmap(struct btrfs_free_space_ctl *ctl,
352 struct btrfs_free_space *info)
353{
354 /*
355 * We always use extents for two reasons:
356 *
357 * - The pinned tree is only used during the process of caching
358 * work.
359 * - Make code simpler. See btrfs_unpin_free_ino().
360 */
361 return false;
362}
363
364static const struct btrfs_free_space_op pinned_free_ino_op = {
365 .recalc_thresholds = pinned_recalc_thresholds,
366 .use_bitmap = pinned_use_bitmap,
367};
368
369void btrfs_init_free_ino_ctl(struct btrfs_root *root)
370{
371 struct btrfs_free_space_ctl *ctl = root->free_ino_ctl;
372 struct btrfs_free_space_ctl *pinned = root->free_ino_pinned;
373
374 spin_lock_init(&ctl->tree_lock);
375 ctl->unit = 1;
376 ctl->start = 0;
377 ctl->private = NULL;
378 ctl->op = &free_ino_op;
379 INIT_LIST_HEAD(&ctl->trimming_ranges);
380 mutex_init(&ctl->cache_writeout_mutex);
381
382 /*
383 * Initially we allow to use 16K of ram to cache chunks of
384 * inode numbers before we resort to bitmaps. This is somewhat
385 * arbitrary, but it will be adjusted in runtime.
386 */
387 ctl->extents_thresh = INIT_THRESHOLD;
388
389 spin_lock_init(&pinned->tree_lock);
390 pinned->unit = 1;
391 pinned->start = 0;
392 pinned->private = NULL;
393 pinned->extents_thresh = 0;
394 pinned->op = &pinned_free_ino_op;
395}
396
397int btrfs_save_ino_cache(struct btrfs_root *root,
398 struct btrfs_trans_handle *trans)
399{
400 struct btrfs_fs_info *fs_info = root->fs_info;
401 struct btrfs_free_space_ctl *ctl = root->free_ino_ctl;
402 struct btrfs_path *path;
403 struct inode *inode;
404 struct btrfs_block_rsv *rsv;
405 struct extent_changeset *data_reserved = NULL;
406 u64 num_bytes;
407 u64 alloc_hint = 0;
408 int ret;
409 int prealloc;
410 bool retry = false;
411
412 /* only fs tree and subvol/snap needs ino cache */
413 if (root->root_key.objectid != BTRFS_FS_TREE_OBJECTID &&
414 (root->root_key.objectid < BTRFS_FIRST_FREE_OBJECTID ||
415 root->root_key.objectid > BTRFS_LAST_FREE_OBJECTID))
416 return 0;
417
418 /* Don't save inode cache if we are deleting this root */
419 if (btrfs_root_refs(&root->root_item) == 0)
420 return 0;
421
422 if (!btrfs_test_opt(fs_info, INODE_MAP_CACHE))
423 return 0;
424
425 path = btrfs_alloc_path();
426 if (!path)
427 return -ENOMEM;
428
429 rsv = trans->block_rsv;
430 trans->block_rsv = &fs_info->trans_block_rsv;
431
432 num_bytes = trans->bytes_reserved;
433 /*
434 * 1 item for inode item insertion if need
435 * 4 items for inode item update (in the worst case)
436 * 1 items for slack space if we need do truncation
437 * 1 item for free space object
438 * 3 items for pre-allocation
439 */
440 trans->bytes_reserved = btrfs_calc_insert_metadata_size(fs_info, 10);
441 ret = btrfs_block_rsv_add(root, trans->block_rsv,
442 trans->bytes_reserved,
443 BTRFS_RESERVE_NO_FLUSH);
444 if (ret)
445 goto out;
446 trace_btrfs_space_reservation(fs_info, "ino_cache", trans->transid,
447 trans->bytes_reserved, 1);
448again:
449 inode = lookup_free_ino_inode(root, path);
450 if (IS_ERR(inode) && (PTR_ERR(inode) != -ENOENT || retry)) {
451 ret = PTR_ERR(inode);
452 goto out_release;
453 }
454
455 if (IS_ERR(inode)) {
456 BUG_ON(retry); /* Logic error */
457 retry = true;
458
459 ret = create_free_ino_inode(root, trans, path);
460 if (ret)
461 goto out_release;
462 goto again;
463 }
464
465 BTRFS_I(inode)->generation = 0;
466 ret = btrfs_update_inode(trans, root, inode);
467 if (ret) {
468 btrfs_abort_transaction(trans, ret);
469 goto out_put;
470 }
471
472 if (i_size_read(inode) > 0) {
473 ret = btrfs_truncate_free_space_cache(trans, NULL, inode);
474 if (ret) {
475 if (ret != -ENOSPC)
476 btrfs_abort_transaction(trans, ret);
477 goto out_put;
478 }
479 }
480
481 spin_lock(&root->ino_cache_lock);
482 if (root->ino_cache_state != BTRFS_CACHE_FINISHED) {
483 ret = -1;
484 spin_unlock(&root->ino_cache_lock);
485 goto out_put;
486 }
487 spin_unlock(&root->ino_cache_lock);
488
489 spin_lock(&ctl->tree_lock);
490 prealloc = sizeof(struct btrfs_free_space) * ctl->free_extents;
491 prealloc = ALIGN(prealloc, PAGE_SIZE);
492 prealloc += ctl->total_bitmaps * PAGE_SIZE;
493 spin_unlock(&ctl->tree_lock);
494
495 /* Just to make sure we have enough space */
496 prealloc += 8 * PAGE_SIZE;
497
498 ret = btrfs_delalloc_reserve_space(BTRFS_I(inode), &data_reserved, 0,
499 prealloc);
500 if (ret)
501 goto out_put;
502
503 ret = btrfs_prealloc_file_range_trans(inode, trans, 0, 0, prealloc,
504 prealloc, prealloc, &alloc_hint);
505 if (ret) {
506 btrfs_delalloc_release_extents(BTRFS_I(inode), prealloc);
507 btrfs_delalloc_release_metadata(BTRFS_I(inode), prealloc, true);
508 goto out_put;
509 }
510
511 ret = btrfs_write_out_ino_cache(root, trans, path, inode);
512 btrfs_delalloc_release_extents(BTRFS_I(inode), prealloc);
513out_put:
514 iput(inode);
515out_release:
516 trace_btrfs_space_reservation(fs_info, "ino_cache", trans->transid,
517 trans->bytes_reserved, 0);
518 btrfs_block_rsv_release(fs_info, trans->block_rsv,
519 trans->bytes_reserved, NULL);
520out:
521 trans->block_rsv = rsv;
522 trans->bytes_reserved = num_bytes;
523
524 btrfs_free_path(path);
525 extent_changeset_free(data_reserved);
526 return ret;
527}
528
529int btrfs_find_highest_objectid(struct btrfs_root *root, u64 *objectid)
530{
531 struct btrfs_path *path;
532 int ret;
533 struct extent_buffer *l;
534 struct btrfs_key search_key;
535 struct btrfs_key found_key;
536 int slot;
537
538 path = btrfs_alloc_path();
539 if (!path)
540 return -ENOMEM;
541
542 search_key.objectid = BTRFS_LAST_FREE_OBJECTID;
543 search_key.type = -1;
544 search_key.offset = (u64)-1;
545 ret = btrfs_search_slot(NULL, root, &search_key, path, 0, 0);
546 if (ret < 0)
547 goto error;
548 BUG_ON(ret == 0); /* Corruption */
549 if (path->slots[0] > 0) {
550 slot = path->slots[0] - 1;
551 l = path->nodes[0];
552 btrfs_item_key_to_cpu(l, &found_key, slot);
553 *objectid = max_t(u64, found_key.objectid,
554 BTRFS_FIRST_FREE_OBJECTID - 1);
555 } else {
556 *objectid = BTRFS_FIRST_FREE_OBJECTID - 1;
557 }
558 ret = 0;
559error:
560 btrfs_free_path(path);
561 return ret;
562}
563
564int btrfs_find_free_objectid(struct btrfs_root *root, u64 *objectid)
565{
566 int ret;
567 mutex_lock(&root->objectid_mutex);
568
569 if (unlikely(root->highest_objectid >= BTRFS_LAST_FREE_OBJECTID)) {
570 btrfs_warn(root->fs_info,
571 "the objectid of root %llu reaches its highest value",
572 root->root_key.objectid);
573 ret = -ENOSPC;
574 goto out;
575 }
576
577 *objectid = ++root->highest_objectid;
578 ret = 0;
579out:
580 mutex_unlock(&root->objectid_mutex);
581 return ret;
582}