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