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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/delay.h>
7#include <linux/kthread.h>
8#include <linux/pagemap.h>
9
10#include "ctree.h"
11#include "disk-io.h"
12#include "free-space-cache.h"
13#include "inode-map.h"
14#include "transaction.h"
15
16static int caching_kthread(void *data)
17{
18 struct btrfs_root *root = data;
19 struct btrfs_fs_info *fs_info = root->fs_info;
20 struct btrfs_free_space_ctl *ctl = root->free_ino_ctl;
21 struct btrfs_key key;
22 struct btrfs_path *path;
23 struct extent_buffer *leaf;
24 u64 last = (u64)-1;
25 int slot;
26 int ret;
27
28 if (!btrfs_test_opt(fs_info, INODE_MAP_CACHE))
29 return 0;
30
31 path = btrfs_alloc_path();
32 if (!path)
33 return -ENOMEM;
34
35 /* Since the commit root is read-only, we can safely skip locking. */
36 path->skip_locking = 1;
37 path->search_commit_root = 1;
38 path->reada = READA_FORWARD;
39
40 key.objectid = BTRFS_FIRST_FREE_OBJECTID;
41 key.offset = 0;
42 key.type = BTRFS_INODE_ITEM_KEY;
43again:
44 /* need to make sure the commit_root doesn't disappear */
45 down_read(&fs_info->commit_root_sem);
46
47 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
48 if (ret < 0)
49 goto out;
50
51 while (1) {
52 if (btrfs_fs_closing(fs_info))
53 goto out;
54
55 leaf = path->nodes[0];
56 slot = path->slots[0];
57 if (slot >= btrfs_header_nritems(leaf)) {
58 ret = btrfs_next_leaf(root, path);
59 if (ret < 0)
60 goto out;
61 else if (ret > 0)
62 break;
63
64 if (need_resched() ||
65 btrfs_transaction_in_commit(fs_info)) {
66 leaf = path->nodes[0];
67
68 if (WARN_ON(btrfs_header_nritems(leaf) == 0))
69 break;
70
71 /*
72 * Save the key so we can advances forward
73 * in the next search.
74 */
75 btrfs_item_key_to_cpu(leaf, &key, 0);
76 btrfs_release_path(path);
77 root->ino_cache_progress = last;
78 up_read(&fs_info->commit_root_sem);
79 schedule_timeout(1);
80 goto again;
81 } else
82 continue;
83 }
84
85 btrfs_item_key_to_cpu(leaf, &key, slot);
86
87 if (key.type != BTRFS_INODE_ITEM_KEY)
88 goto next;
89
90 if (key.objectid >= root->highest_objectid)
91 break;
92
93 if (last != (u64)-1 && last + 1 != key.objectid) {
94 __btrfs_add_free_space(fs_info, ctl, last + 1,
95 key.objectid - last - 1);
96 wake_up(&root->ino_cache_wait);
97 }
98
99 last = key.objectid;
100next:
101 path->slots[0]++;
102 }
103
104 if (last < root->highest_objectid - 1) {
105 __btrfs_add_free_space(fs_info, ctl, last + 1,
106 root->highest_objectid - last - 1);
107 }
108
109 spin_lock(&root->ino_cache_lock);
110 root->ino_cache_state = BTRFS_CACHE_FINISHED;
111 spin_unlock(&root->ino_cache_lock);
112
113 root->ino_cache_progress = (u64)-1;
114 btrfs_unpin_free_ino(root);
115out:
116 wake_up(&root->ino_cache_wait);
117 up_read(&fs_info->commit_root_sem);
118
119 btrfs_free_path(path);
120
121 return ret;
122}
123
124static void start_caching(struct btrfs_root *root)
125{
126 struct btrfs_fs_info *fs_info = root->fs_info;
127 struct btrfs_free_space_ctl *ctl = root->free_ino_ctl;
128 struct task_struct *tsk;
129 int ret;
130 u64 objectid;
131
132 if (!btrfs_test_opt(fs_info, INODE_MAP_CACHE))
133 return;
134
135 spin_lock(&root->ino_cache_lock);
136 if (root->ino_cache_state != BTRFS_CACHE_NO) {
137 spin_unlock(&root->ino_cache_lock);
138 return;
139 }
140
141 root->ino_cache_state = BTRFS_CACHE_STARTED;
142 spin_unlock(&root->ino_cache_lock);
143
144 ret = load_free_ino_cache(fs_info, root);
145 if (ret == 1) {
146 spin_lock(&root->ino_cache_lock);
147 root->ino_cache_state = BTRFS_CACHE_FINISHED;
148 spin_unlock(&root->ino_cache_lock);
149 return;
150 }
151
152 /*
153 * It can be quite time-consuming to fill the cache by searching
154 * through the extent tree, and this can keep ino allocation path
155 * waiting. Therefore at start we quickly find out the highest
156 * inode number and we know we can use inode numbers which fall in
157 * [highest_ino + 1, BTRFS_LAST_FREE_OBJECTID].
158 */
159 ret = btrfs_find_free_objectid(root, &objectid);
160 if (!ret && objectid <= BTRFS_LAST_FREE_OBJECTID) {
161 __btrfs_add_free_space(fs_info, ctl, objectid,
162 BTRFS_LAST_FREE_OBJECTID - objectid + 1);
163 }
164
165 tsk = kthread_run(caching_kthread, root, "btrfs-ino-cache-%llu",
166 root->root_key.objectid);
167 if (IS_ERR(tsk)) {
168 btrfs_warn(fs_info, "failed to start inode caching task");
169 btrfs_clear_pending_and_info(fs_info, INODE_MAP_CACHE,
170 "disabling inode map caching");
171 }
172}
173
174int btrfs_find_free_ino(struct btrfs_root *root, u64 *objectid)
175{
176 if (!btrfs_test_opt(root->fs_info, INODE_MAP_CACHE))
177 return btrfs_find_free_objectid(root, objectid);
178
179again:
180 *objectid = btrfs_find_ino_for_alloc(root);
181
182 if (*objectid != 0)
183 return 0;
184
185 start_caching(root);
186
187 wait_event(root->ino_cache_wait,
188 root->ino_cache_state == BTRFS_CACHE_FINISHED ||
189 root->free_ino_ctl->free_space > 0);
190
191 if (root->ino_cache_state == BTRFS_CACHE_FINISHED &&
192 root->free_ino_ctl->free_space == 0)
193 return -ENOSPC;
194 else
195 goto again;
196}
197
198void btrfs_return_ino(struct btrfs_root *root, u64 objectid)
199{
200 struct btrfs_fs_info *fs_info = root->fs_info;
201 struct btrfs_free_space_ctl *pinned = root->free_ino_pinned;
202
203 if (!btrfs_test_opt(fs_info, INODE_MAP_CACHE))
204 return;
205again:
206 if (root->ino_cache_state == BTRFS_CACHE_FINISHED) {
207 __btrfs_add_free_space(fs_info, pinned, objectid, 1);
208 } else {
209 down_write(&fs_info->commit_root_sem);
210 spin_lock(&root->ino_cache_lock);
211 if (root->ino_cache_state == BTRFS_CACHE_FINISHED) {
212 spin_unlock(&root->ino_cache_lock);
213 up_write(&fs_info->commit_root_sem);
214 goto again;
215 }
216 spin_unlock(&root->ino_cache_lock);
217
218 start_caching(root);
219
220 __btrfs_add_free_space(fs_info, pinned, objectid, 1);
221
222 up_write(&fs_info->commit_root_sem);
223 }
224}
225
226/*
227 * When a transaction is committed, we'll move those inode numbers which are
228 * smaller than root->ino_cache_progress from pinned tree to free_ino tree, and
229 * others will just be dropped, because the commit root we were searching has
230 * changed.
231 *
232 * Must be called with root->fs_info->commit_root_sem held
233 */
234void btrfs_unpin_free_ino(struct btrfs_root *root)
235{
236 struct btrfs_free_space_ctl *ctl = root->free_ino_ctl;
237 struct rb_root *rbroot = &root->free_ino_pinned->free_space_offset;
238 spinlock_t *rbroot_lock = &root->free_ino_pinned->tree_lock;
239 struct btrfs_free_space *info;
240 struct rb_node *n;
241 u64 count;
242
243 if (!btrfs_test_opt(root->fs_info, INODE_MAP_CACHE))
244 return;
245
246 while (1) {
247 bool add_to_ctl = true;
248
249 spin_lock(rbroot_lock);
250 n = rb_first(rbroot);
251 if (!n) {
252 spin_unlock(rbroot_lock);
253 break;
254 }
255
256 info = rb_entry(n, struct btrfs_free_space, offset_index);
257 BUG_ON(info->bitmap); /* Logic error */
258
259 if (info->offset > root->ino_cache_progress)
260 add_to_ctl = false;
261 else if (info->offset + info->bytes > root->ino_cache_progress)
262 count = root->ino_cache_progress - info->offset + 1;
263 else
264 count = info->bytes;
265
266 rb_erase(&info->offset_index, rbroot);
267 spin_unlock(rbroot_lock);
268 if (add_to_ctl)
269 __btrfs_add_free_space(root->fs_info, ctl,
270 info->offset, count);
271 kmem_cache_free(btrfs_free_space_cachep, info);
272 }
273}
274
275#define INIT_THRESHOLD ((SZ_32K / 2) / sizeof(struct btrfs_free_space))
276#define INODES_PER_BITMAP (PAGE_SIZE * 8)
277
278/*
279 * The goal is to keep the memory used by the free_ino tree won't
280 * exceed the memory if we use bitmaps only.
281 */
282static void recalculate_thresholds(struct btrfs_free_space_ctl *ctl)
283{
284 struct btrfs_free_space *info;
285 struct rb_node *n;
286 int max_ino;
287 int max_bitmaps;
288
289 n = rb_last(&ctl->free_space_offset);
290 if (!n) {
291 ctl->extents_thresh = INIT_THRESHOLD;
292 return;
293 }
294 info = rb_entry(n, struct btrfs_free_space, offset_index);
295
296 /*
297 * Find the maximum inode number in the filesystem. Note we
298 * ignore the fact that this can be a bitmap, because we are
299 * not doing precise calculation.
300 */
301 max_ino = info->bytes - 1;
302
303 max_bitmaps = ALIGN(max_ino, INODES_PER_BITMAP) / INODES_PER_BITMAP;
304 if (max_bitmaps <= ctl->total_bitmaps) {
305 ctl->extents_thresh = 0;
306 return;
307 }
308
309 ctl->extents_thresh = (max_bitmaps - ctl->total_bitmaps) *
310 PAGE_SIZE / sizeof(*info);
311}
312
313/*
314 * We don't fall back to bitmap, if we are below the extents threshold
315 * or this chunk of inode numbers is a big one.
316 */
317static bool use_bitmap(struct btrfs_free_space_ctl *ctl,
318 struct btrfs_free_space *info)
319{
320 if (ctl->free_extents < ctl->extents_thresh ||
321 info->bytes > INODES_PER_BITMAP / 10)
322 return false;
323
324 return true;
325}
326
327static const struct btrfs_free_space_op free_ino_op = {
328 .recalc_thresholds = recalculate_thresholds,
329 .use_bitmap = use_bitmap,
330};
331
332static void pinned_recalc_thresholds(struct btrfs_free_space_ctl *ctl)
333{
334}
335
336static bool pinned_use_bitmap(struct btrfs_free_space_ctl *ctl,
337 struct btrfs_free_space *info)
338{
339 /*
340 * We always use extents for two reasons:
341 *
342 * - The pinned tree is only used during the process of caching
343 * work.
344 * - Make code simpler. See btrfs_unpin_free_ino().
345 */
346 return false;
347}
348
349static const struct btrfs_free_space_op pinned_free_ino_op = {
350 .recalc_thresholds = pinned_recalc_thresholds,
351 .use_bitmap = pinned_use_bitmap,
352};
353
354void btrfs_init_free_ino_ctl(struct btrfs_root *root)
355{
356 struct btrfs_free_space_ctl *ctl = root->free_ino_ctl;
357 struct btrfs_free_space_ctl *pinned = root->free_ino_pinned;
358
359 spin_lock_init(&ctl->tree_lock);
360 ctl->unit = 1;
361 ctl->start = 0;
362 ctl->private = NULL;
363 ctl->op = &free_ino_op;
364 INIT_LIST_HEAD(&ctl->trimming_ranges);
365 mutex_init(&ctl->cache_writeout_mutex);
366
367 /*
368 * Initially we allow to use 16K of ram to cache chunks of
369 * inode numbers before we resort to bitmaps. This is somewhat
370 * arbitrary, but it will be adjusted in runtime.
371 */
372 ctl->extents_thresh = INIT_THRESHOLD;
373
374 spin_lock_init(&pinned->tree_lock);
375 pinned->unit = 1;
376 pinned->start = 0;
377 pinned->private = NULL;
378 pinned->extents_thresh = 0;
379 pinned->op = &pinned_free_ino_op;
380}
381
382int btrfs_save_ino_cache(struct btrfs_root *root,
383 struct btrfs_trans_handle *trans)
384{
385 struct btrfs_fs_info *fs_info = root->fs_info;
386 struct btrfs_free_space_ctl *ctl = root->free_ino_ctl;
387 struct btrfs_path *path;
388 struct inode *inode;
389 struct btrfs_block_rsv *rsv;
390 struct extent_changeset *data_reserved = NULL;
391 u64 num_bytes;
392 u64 alloc_hint = 0;
393 int ret;
394 int prealloc;
395 bool retry = false;
396
397 /* only fs tree and subvol/snap needs ino cache */
398 if (root->root_key.objectid != BTRFS_FS_TREE_OBJECTID &&
399 (root->root_key.objectid < BTRFS_FIRST_FREE_OBJECTID ||
400 root->root_key.objectid > BTRFS_LAST_FREE_OBJECTID))
401 return 0;
402
403 /* Don't save inode cache if we are deleting this root */
404 if (btrfs_root_refs(&root->root_item) == 0)
405 return 0;
406
407 if (!btrfs_test_opt(fs_info, INODE_MAP_CACHE))
408 return 0;
409
410 path = btrfs_alloc_path();
411 if (!path)
412 return -ENOMEM;
413
414 rsv = trans->block_rsv;
415 trans->block_rsv = &fs_info->trans_block_rsv;
416
417 num_bytes = trans->bytes_reserved;
418 /*
419 * 1 item for inode item insertion if need
420 * 4 items for inode item update (in the worst case)
421 * 1 items for slack space if we need do truncation
422 * 1 item for free space object
423 * 3 items for pre-allocation
424 */
425 trans->bytes_reserved = btrfs_calc_trans_metadata_size(fs_info, 10);
426 ret = btrfs_block_rsv_add(root, trans->block_rsv,
427 trans->bytes_reserved,
428 BTRFS_RESERVE_NO_FLUSH);
429 if (ret)
430 goto out;
431 trace_btrfs_space_reservation(fs_info, "ino_cache", trans->transid,
432 trans->bytes_reserved, 1);
433again:
434 inode = lookup_free_ino_inode(root, path);
435 if (IS_ERR(inode) && (PTR_ERR(inode) != -ENOENT || retry)) {
436 ret = PTR_ERR(inode);
437 goto out_release;
438 }
439
440 if (IS_ERR(inode)) {
441 BUG_ON(retry); /* Logic error */
442 retry = true;
443
444 ret = create_free_ino_inode(root, trans, path);
445 if (ret)
446 goto out_release;
447 goto again;
448 }
449
450 BTRFS_I(inode)->generation = 0;
451 ret = btrfs_update_inode(trans, root, inode);
452 if (ret) {
453 btrfs_abort_transaction(trans, ret);
454 goto out_put;
455 }
456
457 if (i_size_read(inode) > 0) {
458 ret = btrfs_truncate_free_space_cache(trans, NULL, inode);
459 if (ret) {
460 if (ret != -ENOSPC)
461 btrfs_abort_transaction(trans, ret);
462 goto out_put;
463 }
464 }
465
466 spin_lock(&root->ino_cache_lock);
467 if (root->ino_cache_state != BTRFS_CACHE_FINISHED) {
468 ret = -1;
469 spin_unlock(&root->ino_cache_lock);
470 goto out_put;
471 }
472 spin_unlock(&root->ino_cache_lock);
473
474 spin_lock(&ctl->tree_lock);
475 prealloc = sizeof(struct btrfs_free_space) * ctl->free_extents;
476 prealloc = ALIGN(prealloc, PAGE_SIZE);
477 prealloc += ctl->total_bitmaps * PAGE_SIZE;
478 spin_unlock(&ctl->tree_lock);
479
480 /* Just to make sure we have enough space */
481 prealloc += 8 * PAGE_SIZE;
482
483 ret = btrfs_delalloc_reserve_space(inode, &data_reserved, 0, prealloc);
484 if (ret)
485 goto out_put;
486
487 ret = btrfs_prealloc_file_range_trans(inode, trans, 0, 0, prealloc,
488 prealloc, prealloc, &alloc_hint);
489 if (ret) {
490 btrfs_delalloc_release_extents(BTRFS_I(inode), prealloc, true);
491 goto out_put;
492 }
493
494 ret = btrfs_write_out_ino_cache(root, trans, path, inode);
495 btrfs_delalloc_release_extents(BTRFS_I(inode), prealloc, false);
496out_put:
497 iput(inode);
498out_release:
499 trace_btrfs_space_reservation(fs_info, "ino_cache", trans->transid,
500 trans->bytes_reserved, 0);
501 btrfs_block_rsv_release(fs_info, trans->block_rsv,
502 trans->bytes_reserved);
503out:
504 trans->block_rsv = rsv;
505 trans->bytes_reserved = num_bytes;
506
507 btrfs_free_path(path);
508 extent_changeset_free(data_reserved);
509 return ret;
510}
511
512int btrfs_find_highest_objectid(struct btrfs_root *root, u64 *objectid)
513{
514 struct btrfs_path *path;
515 int ret;
516 struct extent_buffer *l;
517 struct btrfs_key search_key;
518 struct btrfs_key found_key;
519 int slot;
520
521 path = btrfs_alloc_path();
522 if (!path)
523 return -ENOMEM;
524
525 search_key.objectid = BTRFS_LAST_FREE_OBJECTID;
526 search_key.type = -1;
527 search_key.offset = (u64)-1;
528 ret = btrfs_search_slot(NULL, root, &search_key, path, 0, 0);
529 if (ret < 0)
530 goto error;
531 BUG_ON(ret == 0); /* Corruption */
532 if (path->slots[0] > 0) {
533 slot = path->slots[0] - 1;
534 l = path->nodes[0];
535 btrfs_item_key_to_cpu(l, &found_key, slot);
536 *objectid = max_t(u64, found_key.objectid,
537 BTRFS_FIRST_FREE_OBJECTID - 1);
538 } else {
539 *objectid = BTRFS_FIRST_FREE_OBJECTID - 1;
540 }
541 ret = 0;
542error:
543 btrfs_free_path(path);
544 return ret;
545}
546
547int btrfs_find_free_objectid(struct btrfs_root *root, u64 *objectid)
548{
549 int ret;
550 mutex_lock(&root->objectid_mutex);
551
552 if (unlikely(root->highest_objectid >= BTRFS_LAST_FREE_OBJECTID)) {
553 btrfs_warn(root->fs_info,
554 "the objectid of root %llu reaches its highest value",
555 root->root_key.objectid);
556 ret = -ENOSPC;
557 goto out;
558 }
559
560 *objectid = ++root->highest_objectid;
561 ret = 0;
562out:
563 mutex_unlock(&root->objectid_mutex);
564 return ret;
565}
1/*
2 * Copyright (C) 2007 Oracle. All rights reserved.
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public
6 * License v2 as published by the Free Software Foundation.
7 *
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
11 * General Public License for more details.
12 *
13 * You should have received a copy of the GNU General Public
14 * License along with this program; if not, write to the
15 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
16 * Boston, MA 021110-1307, USA.
17 */
18
19#include <linux/delay.h>
20#include <linux/kthread.h>
21#include <linux/pagemap.h>
22
23#include "ctree.h"
24#include "disk-io.h"
25#include "free-space-cache.h"
26#include "inode-map.h"
27#include "transaction.h"
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(root, INODE_MAP_CACHE))
42 return 0;
43
44 path = btrfs_alloc_path();
45 if (!path)
46 return -ENOMEM;
47
48 /* Since the commit root is read-only, we can safely skip locking. */
49 path->skip_locking = 1;
50 path->search_commit_root = 1;
51 path->reada = 2;
52
53 key.objectid = BTRFS_FIRST_FREE_OBJECTID;
54 key.offset = 0;
55 key.type = BTRFS_INODE_ITEM_KEY;
56again:
57 /* need to make sure the commit_root doesn't disappear */
58 down_read(&fs_info->commit_root_sem);
59
60 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
61 if (ret < 0)
62 goto out;
63
64 while (1) {
65 if (btrfs_fs_closing(fs_info))
66 goto out;
67
68 leaf = path->nodes[0];
69 slot = path->slots[0];
70 if (slot >= btrfs_header_nritems(leaf)) {
71 ret = btrfs_next_leaf(root, path);
72 if (ret < 0)
73 goto out;
74 else if (ret > 0)
75 break;
76
77 if (need_resched() ||
78 btrfs_transaction_in_commit(fs_info)) {
79 leaf = path->nodes[0];
80
81 if (WARN_ON(btrfs_header_nritems(leaf) == 0))
82 break;
83
84 /*
85 * Save the key so we can advances forward
86 * in the next search.
87 */
88 btrfs_item_key_to_cpu(leaf, &key, 0);
89 btrfs_release_path(path);
90 root->cache_progress = last;
91 up_read(&fs_info->commit_root_sem);
92 schedule_timeout(1);
93 goto again;
94 } else
95 continue;
96 }
97
98 btrfs_item_key_to_cpu(leaf, &key, slot);
99
100 if (key.type != BTRFS_INODE_ITEM_KEY)
101 goto next;
102
103 if (key.objectid >= root->highest_objectid)
104 break;
105
106 if (last != (u64)-1 && last + 1 != key.objectid) {
107 __btrfs_add_free_space(ctl, last + 1,
108 key.objectid - last - 1);
109 wake_up(&root->cache_wait);
110 }
111
112 last = key.objectid;
113next:
114 path->slots[0]++;
115 }
116
117 if (last < root->highest_objectid - 1) {
118 __btrfs_add_free_space(ctl, last + 1,
119 root->highest_objectid - last - 1);
120 }
121
122 spin_lock(&root->cache_lock);
123 root->cached = BTRFS_CACHE_FINISHED;
124 spin_unlock(&root->cache_lock);
125
126 root->cache_progress = (u64)-1;
127 btrfs_unpin_free_ino(root);
128out:
129 wake_up(&root->cache_wait);
130 up_read(&fs_info->commit_root_sem);
131
132 btrfs_free_path(path);
133
134 return ret;
135}
136
137static void start_caching(struct btrfs_root *root)
138{
139 struct btrfs_free_space_ctl *ctl = root->free_ino_ctl;
140 struct task_struct *tsk;
141 int ret;
142 u64 objectid;
143
144 if (!btrfs_test_opt(root, INODE_MAP_CACHE))
145 return;
146
147 spin_lock(&root->cache_lock);
148 if (root->cached != BTRFS_CACHE_NO) {
149 spin_unlock(&root->cache_lock);
150 return;
151 }
152
153 root->cached = BTRFS_CACHE_STARTED;
154 spin_unlock(&root->cache_lock);
155
156 ret = load_free_ino_cache(root->fs_info, root);
157 if (ret == 1) {
158 spin_lock(&root->cache_lock);
159 root->cached = BTRFS_CACHE_FINISHED;
160 spin_unlock(&root->cache_lock);
161 return;
162 }
163
164 /*
165 * It can be quite time-consuming to fill the cache by searching
166 * through the extent tree, and this can keep ino allocation path
167 * waiting. Therefore at start we quickly find out the highest
168 * inode number and we know we can use inode numbers which fall in
169 * [highest_ino + 1, BTRFS_LAST_FREE_OBJECTID].
170 */
171 ret = btrfs_find_free_objectid(root, &objectid);
172 if (!ret && objectid <= BTRFS_LAST_FREE_OBJECTID) {
173 __btrfs_add_free_space(ctl, objectid,
174 BTRFS_LAST_FREE_OBJECTID - objectid + 1);
175 }
176
177 tsk = kthread_run(caching_kthread, root, "btrfs-ino-cache-%llu\n",
178 root->root_key.objectid);
179 if (IS_ERR(tsk)) {
180 btrfs_warn(root->fs_info, "failed to start inode caching task");
181 btrfs_clear_and_info(root, CHANGE_INODE_CACHE,
182 "disabling inode map caching");
183 }
184}
185
186int btrfs_find_free_ino(struct btrfs_root *root, u64 *objectid)
187{
188 if (!btrfs_test_opt(root, INODE_MAP_CACHE))
189 return btrfs_find_free_objectid(root, objectid);
190
191again:
192 *objectid = btrfs_find_ino_for_alloc(root);
193
194 if (*objectid != 0)
195 return 0;
196
197 start_caching(root);
198
199 wait_event(root->cache_wait,
200 root->cached == BTRFS_CACHE_FINISHED ||
201 root->free_ino_ctl->free_space > 0);
202
203 if (root->cached == BTRFS_CACHE_FINISHED &&
204 root->free_ino_ctl->free_space == 0)
205 return -ENOSPC;
206 else
207 goto again;
208}
209
210void btrfs_return_ino(struct btrfs_root *root, u64 objectid)
211{
212 struct btrfs_free_space_ctl *pinned = root->free_ino_pinned;
213
214 if (!btrfs_test_opt(root, INODE_MAP_CACHE))
215 return;
216again:
217 if (root->cached == BTRFS_CACHE_FINISHED) {
218 __btrfs_add_free_space(pinned, objectid, 1);
219 } else {
220 down_write(&root->fs_info->commit_root_sem);
221 spin_lock(&root->cache_lock);
222 if (root->cached == BTRFS_CACHE_FINISHED) {
223 spin_unlock(&root->cache_lock);
224 up_write(&root->fs_info->commit_root_sem);
225 goto again;
226 }
227 spin_unlock(&root->cache_lock);
228
229 start_caching(root);
230
231 __btrfs_add_free_space(pinned, objectid, 1);
232
233 up_write(&root->fs_info->commit_root_sem);
234 }
235}
236
237/*
238 * When a transaction is committed, we'll move those inode numbers which
239 * are smaller than root->cache_progress from pinned tree to free_ino tree,
240 * and others will just be dropped, because the commit root we were
241 * searching has changed.
242 *
243 * Must be called with root->fs_info->commit_root_sem held
244 */
245void btrfs_unpin_free_ino(struct btrfs_root *root)
246{
247 struct btrfs_free_space_ctl *ctl = root->free_ino_ctl;
248 struct rb_root *rbroot = &root->free_ino_pinned->free_space_offset;
249 struct btrfs_free_space *info;
250 struct rb_node *n;
251 u64 count;
252
253 if (!btrfs_test_opt(root, INODE_MAP_CACHE))
254 return;
255
256 while (1) {
257 n = rb_first(rbroot);
258 if (!n)
259 break;
260
261 info = rb_entry(n, struct btrfs_free_space, offset_index);
262 BUG_ON(info->bitmap); /* Logic error */
263
264 if (info->offset > root->cache_progress)
265 goto free;
266 else if (info->offset + info->bytes > root->cache_progress)
267 count = root->cache_progress - info->offset + 1;
268 else
269 count = info->bytes;
270
271 __btrfs_add_free_space(ctl, info->offset, count);
272free:
273 rb_erase(&info->offset_index, rbroot);
274 kfree(info);
275 }
276}
277
278#define INIT_THRESHOLD (((1024 * 32) / 2) / sizeof(struct btrfs_free_space))
279#define INODES_PER_BITMAP (PAGE_CACHE_SIZE * 8)
280
281/*
282 * The goal is to keep the memory used by the free_ino tree won't
283 * exceed the memory if we use bitmaps only.
284 */
285static void recalculate_thresholds(struct btrfs_free_space_ctl *ctl)
286{
287 struct btrfs_free_space *info;
288 struct rb_node *n;
289 int max_ino;
290 int max_bitmaps;
291
292 n = rb_last(&ctl->free_space_offset);
293 if (!n) {
294 ctl->extents_thresh = INIT_THRESHOLD;
295 return;
296 }
297 info = rb_entry(n, struct btrfs_free_space, offset_index);
298
299 /*
300 * Find the maximum inode number in the filesystem. Note we
301 * ignore the fact that this can be a bitmap, because we are
302 * not doing precise calculation.
303 */
304 max_ino = info->bytes - 1;
305
306 max_bitmaps = ALIGN(max_ino, INODES_PER_BITMAP) / INODES_PER_BITMAP;
307 if (max_bitmaps <= ctl->total_bitmaps) {
308 ctl->extents_thresh = 0;
309 return;
310 }
311
312 ctl->extents_thresh = (max_bitmaps - ctl->total_bitmaps) *
313 PAGE_CACHE_SIZE / sizeof(*info);
314}
315
316/*
317 * We don't fall back to bitmap, if we are below the extents threshold
318 * or this chunk of inode numbers is a big one.
319 */
320static bool use_bitmap(struct btrfs_free_space_ctl *ctl,
321 struct btrfs_free_space *info)
322{
323 if (ctl->free_extents < ctl->extents_thresh ||
324 info->bytes > INODES_PER_BITMAP / 10)
325 return false;
326
327 return true;
328}
329
330static struct btrfs_free_space_op free_ino_op = {
331 .recalc_thresholds = recalculate_thresholds,
332 .use_bitmap = use_bitmap,
333};
334
335static void pinned_recalc_thresholds(struct btrfs_free_space_ctl *ctl)
336{
337}
338
339static bool pinned_use_bitmap(struct btrfs_free_space_ctl *ctl,
340 struct btrfs_free_space *info)
341{
342 /*
343 * We always use extents for two reasons:
344 *
345 * - The pinned tree is only used during the process of caching
346 * work.
347 * - Make code simpler. See btrfs_unpin_free_ino().
348 */
349 return false;
350}
351
352static struct btrfs_free_space_op pinned_free_ino_op = {
353 .recalc_thresholds = pinned_recalc_thresholds,
354 .use_bitmap = pinned_use_bitmap,
355};
356
357void btrfs_init_free_ino_ctl(struct btrfs_root *root)
358{
359 struct btrfs_free_space_ctl *ctl = root->free_ino_ctl;
360 struct btrfs_free_space_ctl *pinned = root->free_ino_pinned;
361
362 spin_lock_init(&ctl->tree_lock);
363 ctl->unit = 1;
364 ctl->start = 0;
365 ctl->private = NULL;
366 ctl->op = &free_ino_op;
367
368 /*
369 * Initially we allow to use 16K of ram to cache chunks of
370 * inode numbers before we resort to bitmaps. This is somewhat
371 * arbitrary, but it will be adjusted in runtime.
372 */
373 ctl->extents_thresh = INIT_THRESHOLD;
374
375 spin_lock_init(&pinned->tree_lock);
376 pinned->unit = 1;
377 pinned->start = 0;
378 pinned->private = NULL;
379 pinned->extents_thresh = 0;
380 pinned->op = &pinned_free_ino_op;
381}
382
383int btrfs_save_ino_cache(struct btrfs_root *root,
384 struct btrfs_trans_handle *trans)
385{
386 struct btrfs_free_space_ctl *ctl = root->free_ino_ctl;
387 struct btrfs_path *path;
388 struct inode *inode;
389 struct btrfs_block_rsv *rsv;
390 u64 num_bytes;
391 u64 alloc_hint = 0;
392 int ret;
393 int prealloc;
394 bool retry = false;
395
396 /* only fs tree and subvol/snap needs ino cache */
397 if (root->root_key.objectid != BTRFS_FS_TREE_OBJECTID &&
398 (root->root_key.objectid < BTRFS_FIRST_FREE_OBJECTID ||
399 root->root_key.objectid > BTRFS_LAST_FREE_OBJECTID))
400 return 0;
401
402 /* Don't save inode cache if we are deleting this root */
403 if (btrfs_root_refs(&root->root_item) == 0)
404 return 0;
405
406 if (!btrfs_test_opt(root, INODE_MAP_CACHE))
407 return 0;
408
409 path = btrfs_alloc_path();
410 if (!path)
411 return -ENOMEM;
412
413 rsv = trans->block_rsv;
414 trans->block_rsv = &root->fs_info->trans_block_rsv;
415
416 num_bytes = trans->bytes_reserved;
417 /*
418 * 1 item for inode item insertion if need
419 * 4 items for inode item update (in the worst case)
420 * 1 items for slack space if we need do truncation
421 * 1 item for free space object
422 * 3 items for pre-allocation
423 */
424 trans->bytes_reserved = btrfs_calc_trans_metadata_size(root, 10);
425 ret = btrfs_block_rsv_add(root, trans->block_rsv,
426 trans->bytes_reserved,
427 BTRFS_RESERVE_NO_FLUSH);
428 if (ret)
429 goto out;
430 trace_btrfs_space_reservation(root->fs_info, "ino_cache",
431 trans->transid, trans->bytes_reserved, 1);
432again:
433 inode = lookup_free_ino_inode(root, path);
434 if (IS_ERR(inode) && (PTR_ERR(inode) != -ENOENT || retry)) {
435 ret = PTR_ERR(inode);
436 goto out_release;
437 }
438
439 if (IS_ERR(inode)) {
440 BUG_ON(retry); /* Logic error */
441 retry = true;
442
443 ret = create_free_ino_inode(root, trans, path);
444 if (ret)
445 goto out_release;
446 goto again;
447 }
448
449 BTRFS_I(inode)->generation = 0;
450 ret = btrfs_update_inode(trans, root, inode);
451 if (ret) {
452 btrfs_abort_transaction(trans, root, ret);
453 goto out_put;
454 }
455
456 if (i_size_read(inode) > 0) {
457 ret = btrfs_truncate_free_space_cache(root, trans, inode);
458 if (ret) {
459 if (ret != -ENOSPC)
460 btrfs_abort_transaction(trans, root, ret);
461 goto out_put;
462 }
463 }
464
465 spin_lock(&root->cache_lock);
466 if (root->cached != BTRFS_CACHE_FINISHED) {
467 ret = -1;
468 spin_unlock(&root->cache_lock);
469 goto out_put;
470 }
471 spin_unlock(&root->cache_lock);
472
473 spin_lock(&ctl->tree_lock);
474 prealloc = sizeof(struct btrfs_free_space) * ctl->free_extents;
475 prealloc = ALIGN(prealloc, PAGE_CACHE_SIZE);
476 prealloc += ctl->total_bitmaps * PAGE_CACHE_SIZE;
477 spin_unlock(&ctl->tree_lock);
478
479 /* Just to make sure we have enough space */
480 prealloc += 8 * PAGE_CACHE_SIZE;
481
482 ret = btrfs_delalloc_reserve_space(inode, prealloc);
483 if (ret)
484 goto out_put;
485
486 ret = btrfs_prealloc_file_range_trans(inode, trans, 0, 0, prealloc,
487 prealloc, prealloc, &alloc_hint);
488 if (ret) {
489 btrfs_delalloc_release_space(inode, prealloc);
490 goto out_put;
491 }
492 btrfs_free_reserved_data_space(inode, prealloc);
493
494 ret = btrfs_write_out_ino_cache(root, trans, path, inode);
495out_put:
496 iput(inode);
497out_release:
498 trace_btrfs_space_reservation(root->fs_info, "ino_cache",
499 trans->transid, trans->bytes_reserved, 0);
500 btrfs_block_rsv_release(root, trans->block_rsv, trans->bytes_reserved);
501out:
502 trans->block_rsv = rsv;
503 trans->bytes_reserved = num_bytes;
504
505 btrfs_free_path(path);
506 return ret;
507}
508
509static int btrfs_find_highest_objectid(struct btrfs_root *root, u64 *objectid)
510{
511 struct btrfs_path *path;
512 int ret;
513 struct extent_buffer *l;
514 struct btrfs_key search_key;
515 struct btrfs_key found_key;
516 int slot;
517
518 path = btrfs_alloc_path();
519 if (!path)
520 return -ENOMEM;
521
522 search_key.objectid = BTRFS_LAST_FREE_OBJECTID;
523 search_key.type = -1;
524 search_key.offset = (u64)-1;
525 ret = btrfs_search_slot(NULL, root, &search_key, path, 0, 0);
526 if (ret < 0)
527 goto error;
528 BUG_ON(ret == 0); /* Corruption */
529 if (path->slots[0] > 0) {
530 slot = path->slots[0] - 1;
531 l = path->nodes[0];
532 btrfs_item_key_to_cpu(l, &found_key, slot);
533 *objectid = max_t(u64, found_key.objectid,
534 BTRFS_FIRST_FREE_OBJECTID - 1);
535 } else {
536 *objectid = BTRFS_FIRST_FREE_OBJECTID - 1;
537 }
538 ret = 0;
539error:
540 btrfs_free_path(path);
541 return ret;
542}
543
544int btrfs_find_free_objectid(struct btrfs_root *root, u64 *objectid)
545{
546 int ret;
547 mutex_lock(&root->objectid_mutex);
548
549 if (unlikely(root->highest_objectid < BTRFS_FIRST_FREE_OBJECTID)) {
550 ret = btrfs_find_highest_objectid(root,
551 &root->highest_objectid);
552 if (ret)
553 goto out;
554 }
555
556 if (unlikely(root->highest_objectid >= BTRFS_LAST_FREE_OBJECTID)) {
557 ret = -ENOSPC;
558 goto out;
559 }
560
561 *objectid = ++root->highest_objectid;
562 ret = 0;
563out:
564 mutex_unlock(&root->objectid_mutex);
565 return ret;
566}