device-dax/kmem: use struct_size()
[linux-2.6-microblaze.git] / fs / btrfs / inode-map.c
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
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
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, 0);
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, 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);
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
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                                        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
189 int 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
194 again:
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
216 void 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;
223 again:
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  */
252 void 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  */
297 static 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  */
332 static 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
342 static const struct btrfs_free_space_op free_ino_op = {
343         .recalc_thresholds      = recalculate_thresholds,
344         .use_bitmap             = use_bitmap,
345 };
346
347 static void pinned_recalc_thresholds(struct btrfs_free_space_ctl *ctl)
348 {
349 }
350
351 static 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
364 static const struct btrfs_free_space_op pinned_free_ino_op = {
365         .recalc_thresholds      = pinned_recalc_thresholds,
366         .use_bitmap             = pinned_use_bitmap,
367 };
368
369 void 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
397 int 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);
448 again:
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);
513 out_put:
514         iput(inode);
515 out_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);
520 out:
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
529 int 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;
559 error:
560         btrfs_free_path(path);
561         return ret;
562 }
563
564 int 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;
579 out:
580         mutex_unlock(&root->objectid_mutex);
581         return ret;
582 }