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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/sched.h>
7#include "ctree.h"
8#include "disk-io.h"
9#include "transaction.h"
10#include "locking.h"
11#include "accessors.h"
12#include "messages.h"
13#include "delalloc-space.h"
14#include "subpage.h"
15#include "defrag.h"
16#include "file-item.h"
17#include "super.h"
18
19static struct kmem_cache *btrfs_inode_defrag_cachep;
20
21/*
22 * When auto defrag is enabled we queue up these defrag structs to remember
23 * which inodes need defragging passes.
24 */
25struct inode_defrag {
26 struct rb_node rb_node;
27 /* Inode number */
28 u64 ino;
29 /*
30 * Transid where the defrag was added, we search for extents newer than
31 * this.
32 */
33 u64 transid;
34
35 /* Root objectid */
36 u64 root;
37
38 /*
39 * The extent size threshold for autodefrag.
40 *
41 * This value is different for compressed/non-compressed extents, thus
42 * needs to be passed from higher layer.
43 * (aka, inode_should_defrag())
44 */
45 u32 extent_thresh;
46};
47
48static int compare_inode_defrag(const struct inode_defrag *defrag1,
49 const struct inode_defrag *defrag2)
50{
51 if (defrag1->root > defrag2->root)
52 return 1;
53 else if (defrag1->root < defrag2->root)
54 return -1;
55 else if (defrag1->ino > defrag2->ino)
56 return 1;
57 else if (defrag1->ino < defrag2->ino)
58 return -1;
59 else
60 return 0;
61}
62
63/*
64 * Insert a record for an inode into the defrag tree. The lock must be held
65 * already.
66 *
67 * If you're inserting a record for an older transid than an existing record,
68 * the transid already in the tree is lowered.
69 */
70static int btrfs_insert_inode_defrag(struct btrfs_inode *inode,
71 struct inode_defrag *defrag)
72{
73 struct btrfs_fs_info *fs_info = inode->root->fs_info;
74 struct inode_defrag *entry;
75 struct rb_node **p;
76 struct rb_node *parent = NULL;
77 int ret;
78
79 p = &fs_info->defrag_inodes.rb_node;
80 while (*p) {
81 parent = *p;
82 entry = rb_entry(parent, struct inode_defrag, rb_node);
83
84 ret = compare_inode_defrag(defrag, entry);
85 if (ret < 0)
86 p = &parent->rb_left;
87 else if (ret > 0)
88 p = &parent->rb_right;
89 else {
90 /*
91 * If we're reinserting an entry for an old defrag run,
92 * make sure to lower the transid of our existing
93 * record.
94 */
95 if (defrag->transid < entry->transid)
96 entry->transid = defrag->transid;
97 entry->extent_thresh = min(defrag->extent_thresh,
98 entry->extent_thresh);
99 return -EEXIST;
100 }
101 }
102 set_bit(BTRFS_INODE_IN_DEFRAG, &inode->runtime_flags);
103 rb_link_node(&defrag->rb_node, parent, p);
104 rb_insert_color(&defrag->rb_node, &fs_info->defrag_inodes);
105 return 0;
106}
107
108static inline int need_auto_defrag(struct btrfs_fs_info *fs_info)
109{
110 if (!btrfs_test_opt(fs_info, AUTO_DEFRAG))
111 return 0;
112
113 if (btrfs_fs_closing(fs_info))
114 return 0;
115
116 return 1;
117}
118
119/*
120 * Insert a defrag record for this inode if auto defrag is enabled. No errors
121 * returned as they're not considered fatal.
122 */
123void btrfs_add_inode_defrag(struct btrfs_inode *inode, u32 extent_thresh)
124{
125 struct btrfs_root *root = inode->root;
126 struct btrfs_fs_info *fs_info = root->fs_info;
127 struct inode_defrag *defrag;
128 int ret;
129
130 if (!need_auto_defrag(fs_info))
131 return;
132
133 if (test_bit(BTRFS_INODE_IN_DEFRAG, &inode->runtime_flags))
134 return;
135
136 defrag = kmem_cache_zalloc(btrfs_inode_defrag_cachep, GFP_NOFS);
137 if (!defrag)
138 return;
139
140 defrag->ino = btrfs_ino(inode);
141 defrag->transid = btrfs_get_root_last_trans(root);
142 defrag->root = btrfs_root_id(root);
143 defrag->extent_thresh = extent_thresh;
144
145 spin_lock(&fs_info->defrag_inodes_lock);
146 if (!test_bit(BTRFS_INODE_IN_DEFRAG, &inode->runtime_flags)) {
147 /*
148 * If we set IN_DEFRAG flag and evict the inode from memory,
149 * and then re-read this inode, this new inode doesn't have
150 * IN_DEFRAG flag. At the case, we may find the existed defrag.
151 */
152 ret = btrfs_insert_inode_defrag(inode, defrag);
153 if (ret)
154 kmem_cache_free(btrfs_inode_defrag_cachep, defrag);
155 } else {
156 kmem_cache_free(btrfs_inode_defrag_cachep, defrag);
157 }
158 spin_unlock(&fs_info->defrag_inodes_lock);
159}
160
161/*
162 * Pick the defragable inode that we want, if it doesn't exist, we will get the
163 * next one.
164 */
165static struct inode_defrag *btrfs_pick_defrag_inode(
166 struct btrfs_fs_info *fs_info, u64 root, u64 ino)
167{
168 struct inode_defrag *entry = NULL;
169 struct inode_defrag tmp;
170 struct rb_node *p;
171 struct rb_node *parent = NULL;
172 int ret;
173
174 tmp.ino = ino;
175 tmp.root = root;
176
177 spin_lock(&fs_info->defrag_inodes_lock);
178 p = fs_info->defrag_inodes.rb_node;
179 while (p) {
180 parent = p;
181 entry = rb_entry(parent, struct inode_defrag, rb_node);
182
183 ret = compare_inode_defrag(&tmp, entry);
184 if (ret < 0)
185 p = parent->rb_left;
186 else if (ret > 0)
187 p = parent->rb_right;
188 else
189 goto out;
190 }
191
192 if (parent && compare_inode_defrag(&tmp, entry) > 0) {
193 parent = rb_next(parent);
194 if (parent)
195 entry = rb_entry(parent, struct inode_defrag, rb_node);
196 else
197 entry = NULL;
198 }
199out:
200 if (entry)
201 rb_erase(parent, &fs_info->defrag_inodes);
202 spin_unlock(&fs_info->defrag_inodes_lock);
203 return entry;
204}
205
206void btrfs_cleanup_defrag_inodes(struct btrfs_fs_info *fs_info)
207{
208 struct inode_defrag *defrag, *next;
209
210 spin_lock(&fs_info->defrag_inodes_lock);
211
212 rbtree_postorder_for_each_entry_safe(defrag, next,
213 &fs_info->defrag_inodes, rb_node)
214 kmem_cache_free(btrfs_inode_defrag_cachep, defrag);
215
216 fs_info->defrag_inodes = RB_ROOT;
217
218 spin_unlock(&fs_info->defrag_inodes_lock);
219}
220
221#define BTRFS_DEFRAG_BATCH 1024
222
223static int btrfs_run_defrag_inode(struct btrfs_fs_info *fs_info,
224 struct inode_defrag *defrag,
225 struct file_ra_state *ra)
226{
227 struct btrfs_root *inode_root;
228 struct inode *inode;
229 struct btrfs_ioctl_defrag_range_args range;
230 int ret = 0;
231 u64 cur = 0;
232
233again:
234 if (test_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state))
235 goto cleanup;
236 if (!need_auto_defrag(fs_info))
237 goto cleanup;
238
239 /* Get the inode */
240 inode_root = btrfs_get_fs_root(fs_info, defrag->root, true);
241 if (IS_ERR(inode_root)) {
242 ret = PTR_ERR(inode_root);
243 goto cleanup;
244 }
245
246 inode = btrfs_iget(defrag->ino, inode_root);
247 btrfs_put_root(inode_root);
248 if (IS_ERR(inode)) {
249 ret = PTR_ERR(inode);
250 goto cleanup;
251 }
252
253 if (cur >= i_size_read(inode)) {
254 iput(inode);
255 goto cleanup;
256 }
257
258 /* Do a chunk of defrag */
259 clear_bit(BTRFS_INODE_IN_DEFRAG, &BTRFS_I(inode)->runtime_flags);
260 memset(&range, 0, sizeof(range));
261 range.len = (u64)-1;
262 range.start = cur;
263 range.extent_thresh = defrag->extent_thresh;
264 file_ra_state_init(ra, inode->i_mapping);
265
266 sb_start_write(fs_info->sb);
267 ret = btrfs_defrag_file(inode, ra, &range, defrag->transid,
268 BTRFS_DEFRAG_BATCH);
269 sb_end_write(fs_info->sb);
270 iput(inode);
271
272 if (ret < 0)
273 goto cleanup;
274
275 cur = max(cur + fs_info->sectorsize, range.start);
276 goto again;
277
278cleanup:
279 kmem_cache_free(btrfs_inode_defrag_cachep, defrag);
280 return ret;
281}
282
283/*
284 * Run through the list of inodes in the FS that need defragging.
285 */
286int btrfs_run_defrag_inodes(struct btrfs_fs_info *fs_info)
287{
288 struct inode_defrag *defrag;
289 u64 first_ino = 0;
290 u64 root_objectid = 0;
291
292 atomic_inc(&fs_info->defrag_running);
293 while (1) {
294 struct file_ra_state ra = { 0 };
295
296 /* Pause the auto defragger. */
297 if (test_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state))
298 break;
299
300 if (!need_auto_defrag(fs_info))
301 break;
302
303 /* find an inode to defrag */
304 defrag = btrfs_pick_defrag_inode(fs_info, root_objectid, first_ino);
305 if (!defrag) {
306 if (root_objectid || first_ino) {
307 root_objectid = 0;
308 first_ino = 0;
309 continue;
310 } else {
311 break;
312 }
313 }
314
315 first_ino = defrag->ino + 1;
316 root_objectid = defrag->root;
317
318 btrfs_run_defrag_inode(fs_info, defrag, &ra);
319 }
320 atomic_dec(&fs_info->defrag_running);
321
322 /*
323 * During unmount, we use the transaction_wait queue to wait for the
324 * defragger to stop.
325 */
326 wake_up(&fs_info->transaction_wait);
327 return 0;
328}
329
330/*
331 * Check if two blocks addresses are close, used by defrag.
332 */
333static bool close_blocks(u64 blocknr, u64 other, u32 blocksize)
334{
335 if (blocknr < other && other - (blocknr + blocksize) < SZ_32K)
336 return true;
337 if (blocknr > other && blocknr - (other + blocksize) < SZ_32K)
338 return true;
339 return false;
340}
341
342/*
343 * Go through all the leaves pointed to by a node and reallocate them so that
344 * disk order is close to key order.
345 */
346static int btrfs_realloc_node(struct btrfs_trans_handle *trans,
347 struct btrfs_root *root,
348 struct extent_buffer *parent,
349 int start_slot, u64 *last_ret,
350 struct btrfs_key *progress)
351{
352 struct btrfs_fs_info *fs_info = root->fs_info;
353 const u32 blocksize = fs_info->nodesize;
354 const int end_slot = btrfs_header_nritems(parent) - 1;
355 u64 search_start = *last_ret;
356 u64 last_block = 0;
357 int ret = 0;
358 bool progress_passed = false;
359
360 /*
361 * COWing must happen through a running transaction, which always
362 * matches the current fs generation (it's a transaction with a state
363 * less than TRANS_STATE_UNBLOCKED). If it doesn't, then turn the fs
364 * into error state to prevent the commit of any transaction.
365 */
366 if (unlikely(trans->transaction != fs_info->running_transaction ||
367 trans->transid != fs_info->generation)) {
368 btrfs_abort_transaction(trans, -EUCLEAN);
369 btrfs_crit(fs_info,
370"unexpected transaction when attempting to reallocate parent %llu for root %llu, transaction %llu running transaction %llu fs generation %llu",
371 parent->start, btrfs_root_id(root), trans->transid,
372 fs_info->running_transaction->transid,
373 fs_info->generation);
374 return -EUCLEAN;
375 }
376
377 if (btrfs_header_nritems(parent) <= 1)
378 return 0;
379
380 for (int i = start_slot; i <= end_slot; i++) {
381 struct extent_buffer *cur;
382 struct btrfs_disk_key disk_key;
383 u64 blocknr;
384 u64 other;
385 bool close = true;
386
387 btrfs_node_key(parent, &disk_key, i);
388 if (!progress_passed && btrfs_comp_keys(&disk_key, progress) < 0)
389 continue;
390
391 progress_passed = true;
392 blocknr = btrfs_node_blockptr(parent, i);
393 if (last_block == 0)
394 last_block = blocknr;
395
396 if (i > 0) {
397 other = btrfs_node_blockptr(parent, i - 1);
398 close = close_blocks(blocknr, other, blocksize);
399 }
400 if (!close && i < end_slot) {
401 other = btrfs_node_blockptr(parent, i + 1);
402 close = close_blocks(blocknr, other, blocksize);
403 }
404 if (close) {
405 last_block = blocknr;
406 continue;
407 }
408
409 cur = btrfs_read_node_slot(parent, i);
410 if (IS_ERR(cur))
411 return PTR_ERR(cur);
412 if (search_start == 0)
413 search_start = last_block;
414
415 btrfs_tree_lock(cur);
416 ret = btrfs_force_cow_block(trans, root, cur, parent, i,
417 &cur, search_start,
418 min(16 * blocksize,
419 (end_slot - i) * blocksize),
420 BTRFS_NESTING_COW);
421 if (ret) {
422 btrfs_tree_unlock(cur);
423 free_extent_buffer(cur);
424 break;
425 }
426 search_start = cur->start;
427 last_block = cur->start;
428 *last_ret = search_start;
429 btrfs_tree_unlock(cur);
430 free_extent_buffer(cur);
431 }
432 return ret;
433}
434
435/*
436 * Defrag all the leaves in a given btree.
437 * Read all the leaves and try to get key order to
438 * better reflect disk order
439 */
440
441static int btrfs_defrag_leaves(struct btrfs_trans_handle *trans,
442 struct btrfs_root *root)
443{
444 struct btrfs_path *path = NULL;
445 struct btrfs_key key;
446 int ret = 0;
447 int wret;
448 int level;
449 int next_key_ret = 0;
450 u64 last_ret = 0;
451
452 if (!test_bit(BTRFS_ROOT_SHAREABLE, &root->state))
453 goto out;
454
455 path = btrfs_alloc_path();
456 if (!path) {
457 ret = -ENOMEM;
458 goto out;
459 }
460
461 level = btrfs_header_level(root->node);
462
463 if (level == 0)
464 goto out;
465
466 if (root->defrag_progress.objectid == 0) {
467 struct extent_buffer *root_node;
468 u32 nritems;
469
470 root_node = btrfs_lock_root_node(root);
471 nritems = btrfs_header_nritems(root_node);
472 root->defrag_max.objectid = 0;
473 /* from above we know this is not a leaf */
474 btrfs_node_key_to_cpu(root_node, &root->defrag_max,
475 nritems - 1);
476 btrfs_tree_unlock(root_node);
477 free_extent_buffer(root_node);
478 memset(&key, 0, sizeof(key));
479 } else {
480 memcpy(&key, &root->defrag_progress, sizeof(key));
481 }
482
483 path->keep_locks = 1;
484
485 ret = btrfs_search_forward(root, &key, path, BTRFS_OLDEST_GENERATION);
486 if (ret < 0)
487 goto out;
488 if (ret > 0) {
489 ret = 0;
490 goto out;
491 }
492 btrfs_release_path(path);
493 /*
494 * We don't need a lock on a leaf. btrfs_realloc_node() will lock all
495 * leafs from path->nodes[1], so set lowest_level to 1 to avoid later
496 * a deadlock (attempting to write lock an already write locked leaf).
497 */
498 path->lowest_level = 1;
499 wret = btrfs_search_slot(trans, root, &key, path, 0, 1);
500
501 if (wret < 0) {
502 ret = wret;
503 goto out;
504 }
505 if (!path->nodes[1]) {
506 ret = 0;
507 goto out;
508 }
509 /*
510 * The node at level 1 must always be locked when our path has
511 * keep_locks set and lowest_level is 1, regardless of the value of
512 * path->slots[1].
513 */
514 ASSERT(path->locks[1] != 0);
515 ret = btrfs_realloc_node(trans, root,
516 path->nodes[1], 0,
517 &last_ret,
518 &root->defrag_progress);
519 if (ret) {
520 WARN_ON(ret == -EAGAIN);
521 goto out;
522 }
523 /*
524 * Now that we reallocated the node we can find the next key. Note that
525 * btrfs_find_next_key() can release our path and do another search
526 * without COWing, this is because even with path->keep_locks = 1,
527 * btrfs_search_slot() / ctree.c:unlock_up() does not keeps a lock on a
528 * node when path->slots[node_level - 1] does not point to the last
529 * item or a slot beyond the last item (ctree.c:unlock_up()). Therefore
530 * we search for the next key after reallocating our node.
531 */
532 path->slots[1] = btrfs_header_nritems(path->nodes[1]);
533 next_key_ret = btrfs_find_next_key(root, path, &key, 1,
534 BTRFS_OLDEST_GENERATION);
535 if (next_key_ret == 0) {
536 memcpy(&root->defrag_progress, &key, sizeof(key));
537 ret = -EAGAIN;
538 }
539out:
540 btrfs_free_path(path);
541 if (ret == -EAGAIN) {
542 if (root->defrag_max.objectid > root->defrag_progress.objectid)
543 goto done;
544 if (root->defrag_max.type > root->defrag_progress.type)
545 goto done;
546 if (root->defrag_max.offset > root->defrag_progress.offset)
547 goto done;
548 ret = 0;
549 }
550done:
551 if (ret != -EAGAIN)
552 memset(&root->defrag_progress, 0,
553 sizeof(root->defrag_progress));
554
555 return ret;
556}
557
558/*
559 * Defrag a given btree. Every leaf in the btree is read and defragmented.
560 */
561int btrfs_defrag_root(struct btrfs_root *root)
562{
563 struct btrfs_fs_info *fs_info = root->fs_info;
564 int ret;
565
566 if (test_and_set_bit(BTRFS_ROOT_DEFRAG_RUNNING, &root->state))
567 return 0;
568
569 while (1) {
570 struct btrfs_trans_handle *trans;
571
572 trans = btrfs_start_transaction(root, 0);
573 if (IS_ERR(trans)) {
574 ret = PTR_ERR(trans);
575 break;
576 }
577
578 ret = btrfs_defrag_leaves(trans, root);
579
580 btrfs_end_transaction(trans);
581 btrfs_btree_balance_dirty(fs_info);
582 cond_resched();
583
584 if (btrfs_fs_closing(fs_info) || ret != -EAGAIN)
585 break;
586
587 if (btrfs_defrag_cancelled(fs_info)) {
588 btrfs_debug(fs_info, "defrag_root cancelled");
589 ret = -EAGAIN;
590 break;
591 }
592 }
593 clear_bit(BTRFS_ROOT_DEFRAG_RUNNING, &root->state);
594 return ret;
595}
596
597/*
598 * Defrag specific helper to get an extent map.
599 *
600 * Differences between this and btrfs_get_extent() are:
601 *
602 * - No extent_map will be added to inode->extent_tree
603 * To reduce memory usage in the long run.
604 *
605 * - Extra optimization to skip file extents older than @newer_than
606 * By using btrfs_search_forward() we can skip entire file ranges that
607 * have extents created in past transactions, because btrfs_search_forward()
608 * will not visit leaves and nodes with a generation smaller than given
609 * minimal generation threshold (@newer_than).
610 *
611 * Return valid em if we find a file extent matching the requirement.
612 * Return NULL if we can not find a file extent matching the requirement.
613 *
614 * Return ERR_PTR() for error.
615 */
616static struct extent_map *defrag_get_extent(struct btrfs_inode *inode,
617 u64 start, u64 newer_than)
618{
619 struct btrfs_root *root = inode->root;
620 struct btrfs_file_extent_item *fi;
621 struct btrfs_path path = { 0 };
622 struct extent_map *em;
623 struct btrfs_key key;
624 u64 ino = btrfs_ino(inode);
625 int ret;
626
627 em = alloc_extent_map();
628 if (!em) {
629 ret = -ENOMEM;
630 goto err;
631 }
632
633 key.objectid = ino;
634 key.type = BTRFS_EXTENT_DATA_KEY;
635 key.offset = start;
636
637 if (newer_than) {
638 ret = btrfs_search_forward(root, &key, &path, newer_than);
639 if (ret < 0)
640 goto err;
641 /* Can't find anything newer */
642 if (ret > 0)
643 goto not_found;
644 } else {
645 ret = btrfs_search_slot(NULL, root, &key, &path, 0, 0);
646 if (ret < 0)
647 goto err;
648 }
649 if (path.slots[0] >= btrfs_header_nritems(path.nodes[0])) {
650 /*
651 * If btrfs_search_slot() makes path to point beyond nritems,
652 * we should not have an empty leaf, as this inode must at
653 * least have its INODE_ITEM.
654 */
655 ASSERT(btrfs_header_nritems(path.nodes[0]));
656 path.slots[0] = btrfs_header_nritems(path.nodes[0]) - 1;
657 }
658 btrfs_item_key_to_cpu(path.nodes[0], &key, path.slots[0]);
659 /* Perfect match, no need to go one slot back */
660 if (key.objectid == ino && key.type == BTRFS_EXTENT_DATA_KEY &&
661 key.offset == start)
662 goto iterate;
663
664 /* We didn't find a perfect match, needs to go one slot back */
665 if (path.slots[0] > 0) {
666 btrfs_item_key_to_cpu(path.nodes[0], &key, path.slots[0]);
667 if (key.objectid == ino && key.type == BTRFS_EXTENT_DATA_KEY)
668 path.slots[0]--;
669 }
670
671iterate:
672 /* Iterate through the path to find a file extent covering @start */
673 while (true) {
674 u64 extent_end;
675
676 if (path.slots[0] >= btrfs_header_nritems(path.nodes[0]))
677 goto next;
678
679 btrfs_item_key_to_cpu(path.nodes[0], &key, path.slots[0]);
680
681 /*
682 * We may go one slot back to INODE_REF/XATTR item, then
683 * need to go forward until we reach an EXTENT_DATA.
684 * But we should still has the correct ino as key.objectid.
685 */
686 if (WARN_ON(key.objectid < ino) || key.type < BTRFS_EXTENT_DATA_KEY)
687 goto next;
688
689 /* It's beyond our target range, definitely not extent found */
690 if (key.objectid > ino || key.type > BTRFS_EXTENT_DATA_KEY)
691 goto not_found;
692
693 /*
694 * | |<- File extent ->|
695 * \- start
696 *
697 * This means there is a hole between start and key.offset.
698 */
699 if (key.offset > start) {
700 em->start = start;
701 em->disk_bytenr = EXTENT_MAP_HOLE;
702 em->disk_num_bytes = 0;
703 em->ram_bytes = 0;
704 em->offset = 0;
705 em->len = key.offset - start;
706 break;
707 }
708
709 fi = btrfs_item_ptr(path.nodes[0], path.slots[0],
710 struct btrfs_file_extent_item);
711 extent_end = btrfs_file_extent_end(&path);
712
713 /*
714 * |<- file extent ->| |
715 * \- start
716 *
717 * We haven't reached start, search next slot.
718 */
719 if (extent_end <= start)
720 goto next;
721
722 /* Now this extent covers @start, convert it to em */
723 btrfs_extent_item_to_extent_map(inode, &path, fi, em);
724 break;
725next:
726 ret = btrfs_next_item(root, &path);
727 if (ret < 0)
728 goto err;
729 if (ret > 0)
730 goto not_found;
731 }
732 btrfs_release_path(&path);
733 return em;
734
735not_found:
736 btrfs_release_path(&path);
737 free_extent_map(em);
738 return NULL;
739
740err:
741 btrfs_release_path(&path);
742 free_extent_map(em);
743 return ERR_PTR(ret);
744}
745
746static struct extent_map *defrag_lookup_extent(struct inode *inode, u64 start,
747 u64 newer_than, bool locked)
748{
749 struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
750 struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
751 struct extent_map *em;
752 const u32 sectorsize = BTRFS_I(inode)->root->fs_info->sectorsize;
753
754 /*
755 * Hopefully we have this extent in the tree already, try without the
756 * full extent lock.
757 */
758 read_lock(&em_tree->lock);
759 em = lookup_extent_mapping(em_tree, start, sectorsize);
760 read_unlock(&em_tree->lock);
761
762 /*
763 * We can get a merged extent, in that case, we need to re-search
764 * tree to get the original em for defrag.
765 *
766 * This is because even if we have adjacent extents that are contiguous
767 * and compatible (same type and flags), we still want to defrag them
768 * so that we use less metadata (extent items in the extent tree and
769 * file extent items in the inode's subvolume tree).
770 */
771 if (em && (em->flags & EXTENT_FLAG_MERGED)) {
772 free_extent_map(em);
773 em = NULL;
774 }
775
776 if (!em) {
777 struct extent_state *cached = NULL;
778 u64 end = start + sectorsize - 1;
779
780 /* Get the big lock and read metadata off disk. */
781 if (!locked)
782 lock_extent(io_tree, start, end, &cached);
783 em = defrag_get_extent(BTRFS_I(inode), start, newer_than);
784 if (!locked)
785 unlock_extent(io_tree, start, end, &cached);
786
787 if (IS_ERR(em))
788 return NULL;
789 }
790
791 return em;
792}
793
794static u32 get_extent_max_capacity(const struct btrfs_fs_info *fs_info,
795 const struct extent_map *em)
796{
797 if (extent_map_is_compressed(em))
798 return BTRFS_MAX_COMPRESSED;
799 return fs_info->max_extent_size;
800}
801
802static bool defrag_check_next_extent(struct inode *inode, struct extent_map *em,
803 u32 extent_thresh, u64 newer_than, bool locked)
804{
805 struct btrfs_fs_info *fs_info = inode_to_fs_info(inode);
806 struct extent_map *next;
807 bool ret = false;
808
809 /* This is the last extent */
810 if (em->start + em->len >= i_size_read(inode))
811 return false;
812
813 /*
814 * Here we need to pass @newer_then when checking the next extent, or
815 * we will hit a case we mark current extent for defrag, but the next
816 * one will not be a target.
817 * This will just cause extra IO without really reducing the fragments.
818 */
819 next = defrag_lookup_extent(inode, em->start + em->len, newer_than, locked);
820 /* No more em or hole */
821 if (!next || next->disk_bytenr >= EXTENT_MAP_LAST_BYTE)
822 goto out;
823 if (next->flags & EXTENT_FLAG_PREALLOC)
824 goto out;
825 /*
826 * If the next extent is at its max capacity, defragging current extent
827 * makes no sense, as the total number of extents won't change.
828 */
829 if (next->len >= get_extent_max_capacity(fs_info, em))
830 goto out;
831 /* Skip older extent */
832 if (next->generation < newer_than)
833 goto out;
834 /* Also check extent size */
835 if (next->len >= extent_thresh)
836 goto out;
837
838 ret = true;
839out:
840 free_extent_map(next);
841 return ret;
842}
843
844/*
845 * Prepare one page to be defragged.
846 *
847 * This will ensure:
848 *
849 * - Returned page is locked and has been set up properly.
850 * - No ordered extent exists in the page.
851 * - The page is uptodate.
852 *
853 * NOTE: Caller should also wait for page writeback after the cluster is
854 * prepared, here we don't do writeback wait for each page.
855 */
856static struct folio *defrag_prepare_one_folio(struct btrfs_inode *inode, pgoff_t index)
857{
858 struct address_space *mapping = inode->vfs_inode.i_mapping;
859 gfp_t mask = btrfs_alloc_write_mask(mapping);
860 u64 page_start = (u64)index << PAGE_SHIFT;
861 u64 page_end = page_start + PAGE_SIZE - 1;
862 struct extent_state *cached_state = NULL;
863 struct folio *folio;
864 int ret;
865
866again:
867 folio = __filemap_get_folio(mapping, index,
868 FGP_LOCK | FGP_ACCESSED | FGP_CREAT, mask);
869 if (IS_ERR(folio))
870 return folio;
871
872 /*
873 * Since we can defragment files opened read-only, we can encounter
874 * transparent huge pages here (see CONFIG_READ_ONLY_THP_FOR_FS). We
875 * can't do I/O using huge pages yet, so return an error for now.
876 * Filesystem transparent huge pages are typically only used for
877 * executables that explicitly enable them, so this isn't very
878 * restrictive.
879 */
880 if (folio_test_large(folio)) {
881 folio_unlock(folio);
882 folio_put(folio);
883 return ERR_PTR(-ETXTBSY);
884 }
885
886 ret = set_folio_extent_mapped(folio);
887 if (ret < 0) {
888 folio_unlock(folio);
889 folio_put(folio);
890 return ERR_PTR(ret);
891 }
892
893 /* Wait for any existing ordered extent in the range */
894 while (1) {
895 struct btrfs_ordered_extent *ordered;
896
897 lock_extent(&inode->io_tree, page_start, page_end, &cached_state);
898 ordered = btrfs_lookup_ordered_range(inode, page_start, PAGE_SIZE);
899 unlock_extent(&inode->io_tree, page_start, page_end,
900 &cached_state);
901 if (!ordered)
902 break;
903
904 folio_unlock(folio);
905 btrfs_start_ordered_extent(ordered);
906 btrfs_put_ordered_extent(ordered);
907 folio_lock(folio);
908 /*
909 * We unlocked the folio above, so we need check if it was
910 * released or not.
911 */
912 if (folio->mapping != mapping || !folio->private) {
913 folio_unlock(folio);
914 folio_put(folio);
915 goto again;
916 }
917 }
918
919 /*
920 * Now the page range has no ordered extent any more. Read the page to
921 * make it uptodate.
922 */
923 if (!folio_test_uptodate(folio)) {
924 btrfs_read_folio(NULL, folio);
925 folio_lock(folio);
926 if (folio->mapping != mapping || !folio->private) {
927 folio_unlock(folio);
928 folio_put(folio);
929 goto again;
930 }
931 if (!folio_test_uptodate(folio)) {
932 folio_unlock(folio);
933 folio_put(folio);
934 return ERR_PTR(-EIO);
935 }
936 }
937 return folio;
938}
939
940struct defrag_target_range {
941 struct list_head list;
942 u64 start;
943 u64 len;
944};
945
946/*
947 * Collect all valid target extents.
948 *
949 * @start: file offset to lookup
950 * @len: length to lookup
951 * @extent_thresh: file extent size threshold, any extent size >= this value
952 * will be ignored
953 * @newer_than: only defrag extents newer than this value
954 * @do_compress: whether the defrag is doing compression
955 * if true, @extent_thresh will be ignored and all regular
956 * file extents meeting @newer_than will be targets.
957 * @locked: if the range has already held extent lock
958 * @target_list: list of targets file extents
959 */
960static int defrag_collect_targets(struct btrfs_inode *inode,
961 u64 start, u64 len, u32 extent_thresh,
962 u64 newer_than, bool do_compress,
963 bool locked, struct list_head *target_list,
964 u64 *last_scanned_ret)
965{
966 struct btrfs_fs_info *fs_info = inode->root->fs_info;
967 bool last_is_target = false;
968 u64 cur = start;
969 int ret = 0;
970
971 while (cur < start + len) {
972 struct extent_map *em;
973 struct defrag_target_range *new;
974 bool next_mergeable = true;
975 u64 range_len;
976
977 last_is_target = false;
978 em = defrag_lookup_extent(&inode->vfs_inode, cur, newer_than, locked);
979 if (!em)
980 break;
981
982 /*
983 * If the file extent is an inlined one, we may still want to
984 * defrag it (fallthrough) if it will cause a regular extent.
985 * This is for users who want to convert inline extents to
986 * regular ones through max_inline= mount option.
987 */
988 if (em->disk_bytenr == EXTENT_MAP_INLINE &&
989 em->len <= inode->root->fs_info->max_inline)
990 goto next;
991
992 /* Skip holes and preallocated extents. */
993 if (em->disk_bytenr == EXTENT_MAP_HOLE ||
994 (em->flags & EXTENT_FLAG_PREALLOC))
995 goto next;
996
997 /* Skip older extent */
998 if (em->generation < newer_than)
999 goto next;
1000
1001 /* This em is under writeback, no need to defrag */
1002 if (em->generation == (u64)-1)
1003 goto next;
1004
1005 /*
1006 * Our start offset might be in the middle of an existing extent
1007 * map, so take that into account.
1008 */
1009 range_len = em->len - (cur - em->start);
1010 /*
1011 * If this range of the extent map is already flagged for delalloc,
1012 * skip it, because:
1013 *
1014 * 1) We could deadlock later, when trying to reserve space for
1015 * delalloc, because in case we can't immediately reserve space
1016 * the flusher can start delalloc and wait for the respective
1017 * ordered extents to complete. The deadlock would happen
1018 * because we do the space reservation while holding the range
1019 * locked, and starting writeback, or finishing an ordered
1020 * extent, requires locking the range;
1021 *
1022 * 2) If there's delalloc there, it means there's dirty pages for
1023 * which writeback has not started yet (we clean the delalloc
1024 * flag when starting writeback and after creating an ordered
1025 * extent). If we mark pages in an adjacent range for defrag,
1026 * then we will have a larger contiguous range for delalloc,
1027 * very likely resulting in a larger extent after writeback is
1028 * triggered (except in a case of free space fragmentation).
1029 */
1030 if (test_range_bit_exists(&inode->io_tree, cur, cur + range_len - 1,
1031 EXTENT_DELALLOC))
1032 goto next;
1033
1034 /*
1035 * For do_compress case, we want to compress all valid file
1036 * extents, thus no @extent_thresh or mergeable check.
1037 */
1038 if (do_compress)
1039 goto add;
1040
1041 /* Skip too large extent */
1042 if (em->len >= extent_thresh)
1043 goto next;
1044
1045 /*
1046 * Skip extents already at its max capacity, this is mostly for
1047 * compressed extents, which max cap is only 128K.
1048 */
1049 if (em->len >= get_extent_max_capacity(fs_info, em))
1050 goto next;
1051
1052 /*
1053 * Normally there are no more extents after an inline one, thus
1054 * @next_mergeable will normally be false and not defragged.
1055 * So if an inline extent passed all above checks, just add it
1056 * for defrag, and be converted to regular extents.
1057 */
1058 if (em->disk_bytenr == EXTENT_MAP_INLINE)
1059 goto add;
1060
1061 next_mergeable = defrag_check_next_extent(&inode->vfs_inode, em,
1062 extent_thresh, newer_than, locked);
1063 if (!next_mergeable) {
1064 struct defrag_target_range *last;
1065
1066 /* Empty target list, no way to merge with last entry */
1067 if (list_empty(target_list))
1068 goto next;
1069 last = list_entry(target_list->prev,
1070 struct defrag_target_range, list);
1071 /* Not mergeable with last entry */
1072 if (last->start + last->len != cur)
1073 goto next;
1074
1075 /* Mergeable, fall through to add it to @target_list. */
1076 }
1077
1078add:
1079 last_is_target = true;
1080 range_len = min(extent_map_end(em), start + len) - cur;
1081 /*
1082 * This one is a good target, check if it can be merged into
1083 * last range of the target list.
1084 */
1085 if (!list_empty(target_list)) {
1086 struct defrag_target_range *last;
1087
1088 last = list_entry(target_list->prev,
1089 struct defrag_target_range, list);
1090 ASSERT(last->start + last->len <= cur);
1091 if (last->start + last->len == cur) {
1092 /* Mergeable, enlarge the last entry */
1093 last->len += range_len;
1094 goto next;
1095 }
1096 /* Fall through to allocate a new entry */
1097 }
1098
1099 /* Allocate new defrag_target_range */
1100 new = kmalloc(sizeof(*new), GFP_NOFS);
1101 if (!new) {
1102 free_extent_map(em);
1103 ret = -ENOMEM;
1104 break;
1105 }
1106 new->start = cur;
1107 new->len = range_len;
1108 list_add_tail(&new->list, target_list);
1109
1110next:
1111 cur = extent_map_end(em);
1112 free_extent_map(em);
1113 }
1114 if (ret < 0) {
1115 struct defrag_target_range *entry;
1116 struct defrag_target_range *tmp;
1117
1118 list_for_each_entry_safe(entry, tmp, target_list, list) {
1119 list_del_init(&entry->list);
1120 kfree(entry);
1121 }
1122 }
1123 if (!ret && last_scanned_ret) {
1124 /*
1125 * If the last extent is not a target, the caller can skip to
1126 * the end of that extent.
1127 * Otherwise, we can only go the end of the specified range.
1128 */
1129 if (!last_is_target)
1130 *last_scanned_ret = max(cur, *last_scanned_ret);
1131 else
1132 *last_scanned_ret = max(start + len, *last_scanned_ret);
1133 }
1134 return ret;
1135}
1136
1137#define CLUSTER_SIZE (SZ_256K)
1138static_assert(PAGE_ALIGNED(CLUSTER_SIZE));
1139
1140/*
1141 * Defrag one contiguous target range.
1142 *
1143 * @inode: target inode
1144 * @target: target range to defrag
1145 * @pages: locked pages covering the defrag range
1146 * @nr_pages: number of locked pages
1147 *
1148 * Caller should ensure:
1149 *
1150 * - Pages are prepared
1151 * Pages should be locked, no ordered extent in the pages range,
1152 * no writeback.
1153 *
1154 * - Extent bits are locked
1155 */
1156static int defrag_one_locked_target(struct btrfs_inode *inode,
1157 struct defrag_target_range *target,
1158 struct folio **folios, int nr_pages,
1159 struct extent_state **cached_state)
1160{
1161 struct btrfs_fs_info *fs_info = inode->root->fs_info;
1162 struct extent_changeset *data_reserved = NULL;
1163 const u64 start = target->start;
1164 const u64 len = target->len;
1165 unsigned long last_index = (start + len - 1) >> PAGE_SHIFT;
1166 unsigned long start_index = start >> PAGE_SHIFT;
1167 unsigned long first_index = folios[0]->index;
1168 int ret = 0;
1169 int i;
1170
1171 ASSERT(last_index - first_index + 1 <= nr_pages);
1172
1173 ret = btrfs_delalloc_reserve_space(inode, &data_reserved, start, len);
1174 if (ret < 0)
1175 return ret;
1176 clear_extent_bit(&inode->io_tree, start, start + len - 1,
1177 EXTENT_DELALLOC | EXTENT_DO_ACCOUNTING |
1178 EXTENT_DEFRAG, cached_state);
1179 set_extent_bit(&inode->io_tree, start, start + len - 1,
1180 EXTENT_DELALLOC | EXTENT_DEFRAG, cached_state);
1181
1182 /* Update the page status */
1183 for (i = start_index - first_index; i <= last_index - first_index; i++) {
1184 folio_clear_checked(folios[i]);
1185 btrfs_folio_clamp_set_dirty(fs_info, folios[i], start, len);
1186 }
1187 btrfs_delalloc_release_extents(inode, len);
1188 extent_changeset_free(data_reserved);
1189
1190 return ret;
1191}
1192
1193static int defrag_one_range(struct btrfs_inode *inode, u64 start, u32 len,
1194 u32 extent_thresh, u64 newer_than, bool do_compress,
1195 u64 *last_scanned_ret)
1196{
1197 struct extent_state *cached_state = NULL;
1198 struct defrag_target_range *entry;
1199 struct defrag_target_range *tmp;
1200 LIST_HEAD(target_list);
1201 struct folio **folios;
1202 const u32 sectorsize = inode->root->fs_info->sectorsize;
1203 u64 last_index = (start + len - 1) >> PAGE_SHIFT;
1204 u64 start_index = start >> PAGE_SHIFT;
1205 unsigned int nr_pages = last_index - start_index + 1;
1206 int ret = 0;
1207 int i;
1208
1209 ASSERT(nr_pages <= CLUSTER_SIZE / PAGE_SIZE);
1210 ASSERT(IS_ALIGNED(start, sectorsize) && IS_ALIGNED(len, sectorsize));
1211
1212 folios = kcalloc(nr_pages, sizeof(struct folio *), GFP_NOFS);
1213 if (!folios)
1214 return -ENOMEM;
1215
1216 /* Prepare all pages */
1217 for (i = 0; i < nr_pages; i++) {
1218 folios[i] = defrag_prepare_one_folio(inode, start_index + i);
1219 if (IS_ERR(folios[i])) {
1220 ret = PTR_ERR(folios[i]);
1221 nr_pages = i;
1222 goto free_folios;
1223 }
1224 }
1225 for (i = 0; i < nr_pages; i++)
1226 folio_wait_writeback(folios[i]);
1227
1228 /* Lock the pages range */
1229 lock_extent(&inode->io_tree, start_index << PAGE_SHIFT,
1230 (last_index << PAGE_SHIFT) + PAGE_SIZE - 1,
1231 &cached_state);
1232 /*
1233 * Now we have a consistent view about the extent map, re-check
1234 * which range really needs to be defragged.
1235 *
1236 * And this time we have extent locked already, pass @locked = true
1237 * so that we won't relock the extent range and cause deadlock.
1238 */
1239 ret = defrag_collect_targets(inode, start, len, extent_thresh,
1240 newer_than, do_compress, true,
1241 &target_list, last_scanned_ret);
1242 if (ret < 0)
1243 goto unlock_extent;
1244
1245 list_for_each_entry(entry, &target_list, list) {
1246 ret = defrag_one_locked_target(inode, entry, folios, nr_pages,
1247 &cached_state);
1248 if (ret < 0)
1249 break;
1250 }
1251
1252 list_for_each_entry_safe(entry, tmp, &target_list, list) {
1253 list_del_init(&entry->list);
1254 kfree(entry);
1255 }
1256unlock_extent:
1257 unlock_extent(&inode->io_tree, start_index << PAGE_SHIFT,
1258 (last_index << PAGE_SHIFT) + PAGE_SIZE - 1,
1259 &cached_state);
1260free_folios:
1261 for (i = 0; i < nr_pages; i++) {
1262 folio_unlock(folios[i]);
1263 folio_put(folios[i]);
1264 }
1265 kfree(folios);
1266 return ret;
1267}
1268
1269static int defrag_one_cluster(struct btrfs_inode *inode,
1270 struct file_ra_state *ra,
1271 u64 start, u32 len, u32 extent_thresh,
1272 u64 newer_than, bool do_compress,
1273 unsigned long *sectors_defragged,
1274 unsigned long max_sectors,
1275 u64 *last_scanned_ret)
1276{
1277 const u32 sectorsize = inode->root->fs_info->sectorsize;
1278 struct defrag_target_range *entry;
1279 struct defrag_target_range *tmp;
1280 LIST_HEAD(target_list);
1281 int ret;
1282
1283 ret = defrag_collect_targets(inode, start, len, extent_thresh,
1284 newer_than, do_compress, false,
1285 &target_list, NULL);
1286 if (ret < 0)
1287 goto out;
1288
1289 list_for_each_entry(entry, &target_list, list) {
1290 u32 range_len = entry->len;
1291
1292 /* Reached or beyond the limit */
1293 if (max_sectors && *sectors_defragged >= max_sectors) {
1294 ret = 1;
1295 break;
1296 }
1297
1298 if (max_sectors)
1299 range_len = min_t(u32, range_len,
1300 (max_sectors - *sectors_defragged) * sectorsize);
1301
1302 /*
1303 * If defrag_one_range() has updated last_scanned_ret,
1304 * our range may already be invalid (e.g. hole punched).
1305 * Skip if our range is before last_scanned_ret, as there is
1306 * no need to defrag the range anymore.
1307 */
1308 if (entry->start + range_len <= *last_scanned_ret)
1309 continue;
1310
1311 page_cache_sync_readahead(inode->vfs_inode.i_mapping,
1312 ra, NULL, entry->start >> PAGE_SHIFT,
1313 ((entry->start + range_len - 1) >> PAGE_SHIFT) -
1314 (entry->start >> PAGE_SHIFT) + 1);
1315 /*
1316 * Here we may not defrag any range if holes are punched before
1317 * we locked the pages.
1318 * But that's fine, it only affects the @sectors_defragged
1319 * accounting.
1320 */
1321 ret = defrag_one_range(inode, entry->start, range_len,
1322 extent_thresh, newer_than, do_compress,
1323 last_scanned_ret);
1324 if (ret < 0)
1325 break;
1326 *sectors_defragged += range_len >>
1327 inode->root->fs_info->sectorsize_bits;
1328 }
1329out:
1330 list_for_each_entry_safe(entry, tmp, &target_list, list) {
1331 list_del_init(&entry->list);
1332 kfree(entry);
1333 }
1334 if (ret >= 0)
1335 *last_scanned_ret = max(*last_scanned_ret, start + len);
1336 return ret;
1337}
1338
1339/*
1340 * Entry point to file defragmentation.
1341 *
1342 * @inode: inode to be defragged
1343 * @ra: readahead state
1344 * @range: defrag options including range and flags
1345 * @newer_than: minimum transid to defrag
1346 * @max_to_defrag: max number of sectors to be defragged, if 0, the whole inode
1347 * will be defragged.
1348 *
1349 * Return <0 for error.
1350 * Return >=0 for the number of sectors defragged, and range->start will be updated
1351 * to indicate the file offset where next defrag should be started at.
1352 * (Mostly for autodefrag, which sets @max_to_defrag thus we may exit early without
1353 * defragging all the range).
1354 */
1355int btrfs_defrag_file(struct inode *inode, struct file_ra_state *ra,
1356 struct btrfs_ioctl_defrag_range_args *range,
1357 u64 newer_than, unsigned long max_to_defrag)
1358{
1359 struct btrfs_fs_info *fs_info = inode_to_fs_info(inode);
1360 unsigned long sectors_defragged = 0;
1361 u64 isize = i_size_read(inode);
1362 u64 cur;
1363 u64 last_byte;
1364 bool do_compress = (range->flags & BTRFS_DEFRAG_RANGE_COMPRESS);
1365 int compress_type = BTRFS_COMPRESS_ZLIB;
1366 int ret = 0;
1367 u32 extent_thresh = range->extent_thresh;
1368 pgoff_t start_index;
1369
1370 ASSERT(ra);
1371
1372 if (isize == 0)
1373 return 0;
1374
1375 if (range->start >= isize)
1376 return -EINVAL;
1377
1378 if (do_compress) {
1379 if (range->compress_type >= BTRFS_NR_COMPRESS_TYPES)
1380 return -EINVAL;
1381 if (range->compress_type)
1382 compress_type = range->compress_type;
1383 }
1384
1385 if (extent_thresh == 0)
1386 extent_thresh = SZ_256K;
1387
1388 if (range->start + range->len > range->start) {
1389 /* Got a specific range */
1390 last_byte = min(isize, range->start + range->len);
1391 } else {
1392 /* Defrag until file end */
1393 last_byte = isize;
1394 }
1395
1396 /* Align the range */
1397 cur = round_down(range->start, fs_info->sectorsize);
1398 last_byte = round_up(last_byte, fs_info->sectorsize) - 1;
1399
1400 /*
1401 * Make writeback start from the beginning of the range, so that the
1402 * defrag range can be written sequentially.
1403 */
1404 start_index = cur >> PAGE_SHIFT;
1405 if (start_index < inode->i_mapping->writeback_index)
1406 inode->i_mapping->writeback_index = start_index;
1407
1408 while (cur < last_byte) {
1409 const unsigned long prev_sectors_defragged = sectors_defragged;
1410 u64 last_scanned = cur;
1411 u64 cluster_end;
1412
1413 if (btrfs_defrag_cancelled(fs_info)) {
1414 ret = -EAGAIN;
1415 break;
1416 }
1417
1418 /* We want the cluster end at page boundary when possible */
1419 cluster_end = (((cur >> PAGE_SHIFT) +
1420 (SZ_256K >> PAGE_SHIFT)) << PAGE_SHIFT) - 1;
1421 cluster_end = min(cluster_end, last_byte);
1422
1423 btrfs_inode_lock(BTRFS_I(inode), 0);
1424 if (IS_SWAPFILE(inode)) {
1425 ret = -ETXTBSY;
1426 btrfs_inode_unlock(BTRFS_I(inode), 0);
1427 break;
1428 }
1429 if (!(inode->i_sb->s_flags & SB_ACTIVE)) {
1430 btrfs_inode_unlock(BTRFS_I(inode), 0);
1431 break;
1432 }
1433 if (do_compress)
1434 BTRFS_I(inode)->defrag_compress = compress_type;
1435 ret = defrag_one_cluster(BTRFS_I(inode), ra, cur,
1436 cluster_end + 1 - cur, extent_thresh,
1437 newer_than, do_compress, §ors_defragged,
1438 max_to_defrag, &last_scanned);
1439
1440 if (sectors_defragged > prev_sectors_defragged)
1441 balance_dirty_pages_ratelimited(inode->i_mapping);
1442
1443 btrfs_inode_unlock(BTRFS_I(inode), 0);
1444 if (ret < 0)
1445 break;
1446 cur = max(cluster_end + 1, last_scanned);
1447 if (ret > 0) {
1448 ret = 0;
1449 break;
1450 }
1451 cond_resched();
1452 }
1453
1454 /*
1455 * Update range.start for autodefrag, this will indicate where to start
1456 * in next run.
1457 */
1458 range->start = cur;
1459 if (sectors_defragged) {
1460 /*
1461 * We have defragged some sectors, for compression case they
1462 * need to be written back immediately.
1463 */
1464 if (range->flags & BTRFS_DEFRAG_RANGE_START_IO) {
1465 filemap_flush(inode->i_mapping);
1466 if (test_bit(BTRFS_INODE_HAS_ASYNC_EXTENT,
1467 &BTRFS_I(inode)->runtime_flags))
1468 filemap_flush(inode->i_mapping);
1469 }
1470 if (range->compress_type == BTRFS_COMPRESS_LZO)
1471 btrfs_set_fs_incompat(fs_info, COMPRESS_LZO);
1472 else if (range->compress_type == BTRFS_COMPRESS_ZSTD)
1473 btrfs_set_fs_incompat(fs_info, COMPRESS_ZSTD);
1474 ret = sectors_defragged;
1475 }
1476 if (do_compress) {
1477 btrfs_inode_lock(BTRFS_I(inode), 0);
1478 BTRFS_I(inode)->defrag_compress = BTRFS_COMPRESS_NONE;
1479 btrfs_inode_unlock(BTRFS_I(inode), 0);
1480 }
1481 return ret;
1482}
1483
1484void __cold btrfs_auto_defrag_exit(void)
1485{
1486 kmem_cache_destroy(btrfs_inode_defrag_cachep);
1487}
1488
1489int __init btrfs_auto_defrag_init(void)
1490{
1491 btrfs_inode_defrag_cachep = kmem_cache_create("btrfs_inode_defrag",
1492 sizeof(struct inode_defrag), 0, 0, NULL);
1493 if (!btrfs_inode_defrag_cachep)
1494 return -ENOMEM;
1495
1496 return 0;
1497}
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (C) 2007 Oracle. All rights reserved.
4 */
5
6#include <linux/sched.h>
7#include "ctree.h"
8#include "disk-io.h"
9#include "transaction.h"
10#include "locking.h"
11#include "accessors.h"
12#include "messages.h"
13#include "delalloc-space.h"
14#include "subpage.h"
15#include "defrag.h"
16#include "file-item.h"
17#include "super.h"
18
19static struct kmem_cache *btrfs_inode_defrag_cachep;
20
21/*
22 * When auto defrag is enabled we queue up these defrag structs to remember
23 * which inodes need defragging passes.
24 */
25struct inode_defrag {
26 struct rb_node rb_node;
27 /* Inode number */
28 u64 ino;
29 /*
30 * Transid where the defrag was added, we search for extents newer than
31 * this.
32 */
33 u64 transid;
34
35 /* Root objectid */
36 u64 root;
37
38 /*
39 * The extent size threshold for autodefrag.
40 *
41 * This value is different for compressed/non-compressed extents, thus
42 * needs to be passed from higher layer.
43 * (aka, inode_should_defrag())
44 */
45 u32 extent_thresh;
46};
47
48static int __compare_inode_defrag(struct inode_defrag *defrag1,
49 struct inode_defrag *defrag2)
50{
51 if (defrag1->root > defrag2->root)
52 return 1;
53 else if (defrag1->root < defrag2->root)
54 return -1;
55 else if (defrag1->ino > defrag2->ino)
56 return 1;
57 else if (defrag1->ino < defrag2->ino)
58 return -1;
59 else
60 return 0;
61}
62
63/*
64 * Pop a record for an inode into the defrag tree. The lock must be held
65 * already.
66 *
67 * If you're inserting a record for an older transid than an existing record,
68 * the transid already in the tree is lowered.
69 *
70 * If an existing record is found the defrag item you pass in is freed.
71 */
72static int __btrfs_add_inode_defrag(struct btrfs_inode *inode,
73 struct inode_defrag *defrag)
74{
75 struct btrfs_fs_info *fs_info = inode->root->fs_info;
76 struct inode_defrag *entry;
77 struct rb_node **p;
78 struct rb_node *parent = NULL;
79 int ret;
80
81 p = &fs_info->defrag_inodes.rb_node;
82 while (*p) {
83 parent = *p;
84 entry = rb_entry(parent, struct inode_defrag, rb_node);
85
86 ret = __compare_inode_defrag(defrag, entry);
87 if (ret < 0)
88 p = &parent->rb_left;
89 else if (ret > 0)
90 p = &parent->rb_right;
91 else {
92 /*
93 * If we're reinserting an entry for an old defrag run,
94 * make sure to lower the transid of our existing
95 * record.
96 */
97 if (defrag->transid < entry->transid)
98 entry->transid = defrag->transid;
99 entry->extent_thresh = min(defrag->extent_thresh,
100 entry->extent_thresh);
101 return -EEXIST;
102 }
103 }
104 set_bit(BTRFS_INODE_IN_DEFRAG, &inode->runtime_flags);
105 rb_link_node(&defrag->rb_node, parent, p);
106 rb_insert_color(&defrag->rb_node, &fs_info->defrag_inodes);
107 return 0;
108}
109
110static inline int __need_auto_defrag(struct btrfs_fs_info *fs_info)
111{
112 if (!btrfs_test_opt(fs_info, AUTO_DEFRAG))
113 return 0;
114
115 if (btrfs_fs_closing(fs_info))
116 return 0;
117
118 return 1;
119}
120
121/*
122 * Insert a defrag record for this inode if auto defrag is enabled.
123 */
124int btrfs_add_inode_defrag(struct btrfs_trans_handle *trans,
125 struct btrfs_inode *inode, u32 extent_thresh)
126{
127 struct btrfs_root *root = inode->root;
128 struct btrfs_fs_info *fs_info = root->fs_info;
129 struct inode_defrag *defrag;
130 u64 transid;
131 int ret;
132
133 if (!__need_auto_defrag(fs_info))
134 return 0;
135
136 if (test_bit(BTRFS_INODE_IN_DEFRAG, &inode->runtime_flags))
137 return 0;
138
139 if (trans)
140 transid = trans->transid;
141 else
142 transid = inode->root->last_trans;
143
144 defrag = kmem_cache_zalloc(btrfs_inode_defrag_cachep, GFP_NOFS);
145 if (!defrag)
146 return -ENOMEM;
147
148 defrag->ino = btrfs_ino(inode);
149 defrag->transid = transid;
150 defrag->root = root->root_key.objectid;
151 defrag->extent_thresh = extent_thresh;
152
153 spin_lock(&fs_info->defrag_inodes_lock);
154 if (!test_bit(BTRFS_INODE_IN_DEFRAG, &inode->runtime_flags)) {
155 /*
156 * If we set IN_DEFRAG flag and evict the inode from memory,
157 * and then re-read this inode, this new inode doesn't have
158 * IN_DEFRAG flag. At the case, we may find the existed defrag.
159 */
160 ret = __btrfs_add_inode_defrag(inode, defrag);
161 if (ret)
162 kmem_cache_free(btrfs_inode_defrag_cachep, defrag);
163 } else {
164 kmem_cache_free(btrfs_inode_defrag_cachep, defrag);
165 }
166 spin_unlock(&fs_info->defrag_inodes_lock);
167 return 0;
168}
169
170/*
171 * Pick the defragable inode that we want, if it doesn't exist, we will get the
172 * next one.
173 */
174static struct inode_defrag *btrfs_pick_defrag_inode(
175 struct btrfs_fs_info *fs_info, u64 root, u64 ino)
176{
177 struct inode_defrag *entry = NULL;
178 struct inode_defrag tmp;
179 struct rb_node *p;
180 struct rb_node *parent = NULL;
181 int ret;
182
183 tmp.ino = ino;
184 tmp.root = root;
185
186 spin_lock(&fs_info->defrag_inodes_lock);
187 p = fs_info->defrag_inodes.rb_node;
188 while (p) {
189 parent = p;
190 entry = rb_entry(parent, struct inode_defrag, rb_node);
191
192 ret = __compare_inode_defrag(&tmp, entry);
193 if (ret < 0)
194 p = parent->rb_left;
195 else if (ret > 0)
196 p = parent->rb_right;
197 else
198 goto out;
199 }
200
201 if (parent && __compare_inode_defrag(&tmp, entry) > 0) {
202 parent = rb_next(parent);
203 if (parent)
204 entry = rb_entry(parent, struct inode_defrag, rb_node);
205 else
206 entry = NULL;
207 }
208out:
209 if (entry)
210 rb_erase(parent, &fs_info->defrag_inodes);
211 spin_unlock(&fs_info->defrag_inodes_lock);
212 return entry;
213}
214
215void btrfs_cleanup_defrag_inodes(struct btrfs_fs_info *fs_info)
216{
217 struct inode_defrag *defrag;
218 struct rb_node *node;
219
220 spin_lock(&fs_info->defrag_inodes_lock);
221 node = rb_first(&fs_info->defrag_inodes);
222 while (node) {
223 rb_erase(node, &fs_info->defrag_inodes);
224 defrag = rb_entry(node, struct inode_defrag, rb_node);
225 kmem_cache_free(btrfs_inode_defrag_cachep, defrag);
226
227 cond_resched_lock(&fs_info->defrag_inodes_lock);
228
229 node = rb_first(&fs_info->defrag_inodes);
230 }
231 spin_unlock(&fs_info->defrag_inodes_lock);
232}
233
234#define BTRFS_DEFRAG_BATCH 1024
235
236static int __btrfs_run_defrag_inode(struct btrfs_fs_info *fs_info,
237 struct inode_defrag *defrag)
238{
239 struct btrfs_root *inode_root;
240 struct inode *inode;
241 struct btrfs_ioctl_defrag_range_args range;
242 int ret = 0;
243 u64 cur = 0;
244
245again:
246 if (test_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state))
247 goto cleanup;
248 if (!__need_auto_defrag(fs_info))
249 goto cleanup;
250
251 /* Get the inode */
252 inode_root = btrfs_get_fs_root(fs_info, defrag->root, true);
253 if (IS_ERR(inode_root)) {
254 ret = PTR_ERR(inode_root);
255 goto cleanup;
256 }
257
258 inode = btrfs_iget(fs_info->sb, defrag->ino, inode_root);
259 btrfs_put_root(inode_root);
260 if (IS_ERR(inode)) {
261 ret = PTR_ERR(inode);
262 goto cleanup;
263 }
264
265 if (cur >= i_size_read(inode)) {
266 iput(inode);
267 goto cleanup;
268 }
269
270 /* Do a chunk of defrag */
271 clear_bit(BTRFS_INODE_IN_DEFRAG, &BTRFS_I(inode)->runtime_flags);
272 memset(&range, 0, sizeof(range));
273 range.len = (u64)-1;
274 range.start = cur;
275 range.extent_thresh = defrag->extent_thresh;
276
277 sb_start_write(fs_info->sb);
278 ret = btrfs_defrag_file(inode, NULL, &range, defrag->transid,
279 BTRFS_DEFRAG_BATCH);
280 sb_end_write(fs_info->sb);
281 iput(inode);
282
283 if (ret < 0)
284 goto cleanup;
285
286 cur = max(cur + fs_info->sectorsize, range.start);
287 goto again;
288
289cleanup:
290 kmem_cache_free(btrfs_inode_defrag_cachep, defrag);
291 return ret;
292}
293
294/*
295 * Run through the list of inodes in the FS that need defragging.
296 */
297int btrfs_run_defrag_inodes(struct btrfs_fs_info *fs_info)
298{
299 struct inode_defrag *defrag;
300 u64 first_ino = 0;
301 u64 root_objectid = 0;
302
303 atomic_inc(&fs_info->defrag_running);
304 while (1) {
305 /* Pause the auto defragger. */
306 if (test_bit(BTRFS_FS_STATE_REMOUNTING, &fs_info->fs_state))
307 break;
308
309 if (!__need_auto_defrag(fs_info))
310 break;
311
312 /* find an inode to defrag */
313 defrag = btrfs_pick_defrag_inode(fs_info, root_objectid, first_ino);
314 if (!defrag) {
315 if (root_objectid || first_ino) {
316 root_objectid = 0;
317 first_ino = 0;
318 continue;
319 } else {
320 break;
321 }
322 }
323
324 first_ino = defrag->ino + 1;
325 root_objectid = defrag->root;
326
327 __btrfs_run_defrag_inode(fs_info, defrag);
328 }
329 atomic_dec(&fs_info->defrag_running);
330
331 /*
332 * During unmount, we use the transaction_wait queue to wait for the
333 * defragger to stop.
334 */
335 wake_up(&fs_info->transaction_wait);
336 return 0;
337}
338
339/*
340 * Check if two blocks addresses are close, used by defrag.
341 */
342static bool close_blocks(u64 blocknr, u64 other, u32 blocksize)
343{
344 if (blocknr < other && other - (blocknr + blocksize) < SZ_32K)
345 return true;
346 if (blocknr > other && blocknr - (other + blocksize) < SZ_32K)
347 return true;
348 return false;
349}
350
351/*
352 * Go through all the leaves pointed to by a node and reallocate them so that
353 * disk order is close to key order.
354 */
355static int btrfs_realloc_node(struct btrfs_trans_handle *trans,
356 struct btrfs_root *root,
357 struct extent_buffer *parent,
358 int start_slot, u64 *last_ret,
359 struct btrfs_key *progress)
360{
361 struct btrfs_fs_info *fs_info = root->fs_info;
362 const u32 blocksize = fs_info->nodesize;
363 const int end_slot = btrfs_header_nritems(parent) - 1;
364 u64 search_start = *last_ret;
365 u64 last_block = 0;
366 int ret = 0;
367 bool progress_passed = false;
368
369 /*
370 * COWing must happen through a running transaction, which always
371 * matches the current fs generation (it's a transaction with a state
372 * less than TRANS_STATE_UNBLOCKED). If it doesn't, then turn the fs
373 * into error state to prevent the commit of any transaction.
374 */
375 if (unlikely(trans->transaction != fs_info->running_transaction ||
376 trans->transid != fs_info->generation)) {
377 btrfs_abort_transaction(trans, -EUCLEAN);
378 btrfs_crit(fs_info,
379"unexpected transaction when attempting to reallocate parent %llu for root %llu, transaction %llu running transaction %llu fs generation %llu",
380 parent->start, btrfs_root_id(root), trans->transid,
381 fs_info->running_transaction->transid,
382 fs_info->generation);
383 return -EUCLEAN;
384 }
385
386 if (btrfs_header_nritems(parent) <= 1)
387 return 0;
388
389 for (int i = start_slot; i <= end_slot; i++) {
390 struct extent_buffer *cur;
391 struct btrfs_disk_key disk_key;
392 u64 blocknr;
393 u64 other;
394 bool close = true;
395
396 btrfs_node_key(parent, &disk_key, i);
397 if (!progress_passed && btrfs_comp_keys(&disk_key, progress) < 0)
398 continue;
399
400 progress_passed = true;
401 blocknr = btrfs_node_blockptr(parent, i);
402 if (last_block == 0)
403 last_block = blocknr;
404
405 if (i > 0) {
406 other = btrfs_node_blockptr(parent, i - 1);
407 close = close_blocks(blocknr, other, blocksize);
408 }
409 if (!close && i < end_slot) {
410 other = btrfs_node_blockptr(parent, i + 1);
411 close = close_blocks(blocknr, other, blocksize);
412 }
413 if (close) {
414 last_block = blocknr;
415 continue;
416 }
417
418 cur = btrfs_read_node_slot(parent, i);
419 if (IS_ERR(cur))
420 return PTR_ERR(cur);
421 if (search_start == 0)
422 search_start = last_block;
423
424 btrfs_tree_lock(cur);
425 ret = btrfs_force_cow_block(trans, root, cur, parent, i,
426 &cur, search_start,
427 min(16 * blocksize,
428 (end_slot - i) * blocksize),
429 BTRFS_NESTING_COW);
430 if (ret) {
431 btrfs_tree_unlock(cur);
432 free_extent_buffer(cur);
433 break;
434 }
435 search_start = cur->start;
436 last_block = cur->start;
437 *last_ret = search_start;
438 btrfs_tree_unlock(cur);
439 free_extent_buffer(cur);
440 }
441 return ret;
442}
443
444/*
445 * Defrag all the leaves in a given btree.
446 * Read all the leaves and try to get key order to
447 * better reflect disk order
448 */
449
450static int btrfs_defrag_leaves(struct btrfs_trans_handle *trans,
451 struct btrfs_root *root)
452{
453 struct btrfs_path *path = NULL;
454 struct btrfs_key key;
455 int ret = 0;
456 int wret;
457 int level;
458 int next_key_ret = 0;
459 u64 last_ret = 0;
460
461 if (!test_bit(BTRFS_ROOT_SHAREABLE, &root->state))
462 goto out;
463
464 path = btrfs_alloc_path();
465 if (!path) {
466 ret = -ENOMEM;
467 goto out;
468 }
469
470 level = btrfs_header_level(root->node);
471
472 if (level == 0)
473 goto out;
474
475 if (root->defrag_progress.objectid == 0) {
476 struct extent_buffer *root_node;
477 u32 nritems;
478
479 root_node = btrfs_lock_root_node(root);
480 nritems = btrfs_header_nritems(root_node);
481 root->defrag_max.objectid = 0;
482 /* from above we know this is not a leaf */
483 btrfs_node_key_to_cpu(root_node, &root->defrag_max,
484 nritems - 1);
485 btrfs_tree_unlock(root_node);
486 free_extent_buffer(root_node);
487 memset(&key, 0, sizeof(key));
488 } else {
489 memcpy(&key, &root->defrag_progress, sizeof(key));
490 }
491
492 path->keep_locks = 1;
493
494 ret = btrfs_search_forward(root, &key, path, BTRFS_OLDEST_GENERATION);
495 if (ret < 0)
496 goto out;
497 if (ret > 0) {
498 ret = 0;
499 goto out;
500 }
501 btrfs_release_path(path);
502 /*
503 * We don't need a lock on a leaf. btrfs_realloc_node() will lock all
504 * leafs from path->nodes[1], so set lowest_level to 1 to avoid later
505 * a deadlock (attempting to write lock an already write locked leaf).
506 */
507 path->lowest_level = 1;
508 wret = btrfs_search_slot(trans, root, &key, path, 0, 1);
509
510 if (wret < 0) {
511 ret = wret;
512 goto out;
513 }
514 if (!path->nodes[1]) {
515 ret = 0;
516 goto out;
517 }
518 /*
519 * The node at level 1 must always be locked when our path has
520 * keep_locks set and lowest_level is 1, regardless of the value of
521 * path->slots[1].
522 */
523 ASSERT(path->locks[1] != 0);
524 ret = btrfs_realloc_node(trans, root,
525 path->nodes[1], 0,
526 &last_ret,
527 &root->defrag_progress);
528 if (ret) {
529 WARN_ON(ret == -EAGAIN);
530 goto out;
531 }
532 /*
533 * Now that we reallocated the node we can find the next key. Note that
534 * btrfs_find_next_key() can release our path and do another search
535 * without COWing, this is because even with path->keep_locks = 1,
536 * btrfs_search_slot() / ctree.c:unlock_up() does not keeps a lock on a
537 * node when path->slots[node_level - 1] does not point to the last
538 * item or a slot beyond the last item (ctree.c:unlock_up()). Therefore
539 * we search for the next key after reallocating our node.
540 */
541 path->slots[1] = btrfs_header_nritems(path->nodes[1]);
542 next_key_ret = btrfs_find_next_key(root, path, &key, 1,
543 BTRFS_OLDEST_GENERATION);
544 if (next_key_ret == 0) {
545 memcpy(&root->defrag_progress, &key, sizeof(key));
546 ret = -EAGAIN;
547 }
548out:
549 btrfs_free_path(path);
550 if (ret == -EAGAIN) {
551 if (root->defrag_max.objectid > root->defrag_progress.objectid)
552 goto done;
553 if (root->defrag_max.type > root->defrag_progress.type)
554 goto done;
555 if (root->defrag_max.offset > root->defrag_progress.offset)
556 goto done;
557 ret = 0;
558 }
559done:
560 if (ret != -EAGAIN)
561 memset(&root->defrag_progress, 0,
562 sizeof(root->defrag_progress));
563
564 return ret;
565}
566
567/*
568 * Defrag a given btree. Every leaf in the btree is read and defragmented.
569 */
570int btrfs_defrag_root(struct btrfs_root *root)
571{
572 struct btrfs_fs_info *fs_info = root->fs_info;
573 int ret;
574
575 if (test_and_set_bit(BTRFS_ROOT_DEFRAG_RUNNING, &root->state))
576 return 0;
577
578 while (1) {
579 struct btrfs_trans_handle *trans;
580
581 trans = btrfs_start_transaction(root, 0);
582 if (IS_ERR(trans)) {
583 ret = PTR_ERR(trans);
584 break;
585 }
586
587 ret = btrfs_defrag_leaves(trans, root);
588
589 btrfs_end_transaction(trans);
590 btrfs_btree_balance_dirty(fs_info);
591 cond_resched();
592
593 if (btrfs_fs_closing(fs_info) || ret != -EAGAIN)
594 break;
595
596 if (btrfs_defrag_cancelled(fs_info)) {
597 btrfs_debug(fs_info, "defrag_root cancelled");
598 ret = -EAGAIN;
599 break;
600 }
601 }
602 clear_bit(BTRFS_ROOT_DEFRAG_RUNNING, &root->state);
603 return ret;
604}
605
606/*
607 * Defrag specific helper to get an extent map.
608 *
609 * Differences between this and btrfs_get_extent() are:
610 *
611 * - No extent_map will be added to inode->extent_tree
612 * To reduce memory usage in the long run.
613 *
614 * - Extra optimization to skip file extents older than @newer_than
615 * By using btrfs_search_forward() we can skip entire file ranges that
616 * have extents created in past transactions, because btrfs_search_forward()
617 * will not visit leaves and nodes with a generation smaller than given
618 * minimal generation threshold (@newer_than).
619 *
620 * Return valid em if we find a file extent matching the requirement.
621 * Return NULL if we can not find a file extent matching the requirement.
622 *
623 * Return ERR_PTR() for error.
624 */
625static struct extent_map *defrag_get_extent(struct btrfs_inode *inode,
626 u64 start, u64 newer_than)
627{
628 struct btrfs_root *root = inode->root;
629 struct btrfs_file_extent_item *fi;
630 struct btrfs_path path = { 0 };
631 struct extent_map *em;
632 struct btrfs_key key;
633 u64 ino = btrfs_ino(inode);
634 int ret;
635
636 em = alloc_extent_map();
637 if (!em) {
638 ret = -ENOMEM;
639 goto err;
640 }
641
642 key.objectid = ino;
643 key.type = BTRFS_EXTENT_DATA_KEY;
644 key.offset = start;
645
646 if (newer_than) {
647 ret = btrfs_search_forward(root, &key, &path, newer_than);
648 if (ret < 0)
649 goto err;
650 /* Can't find anything newer */
651 if (ret > 0)
652 goto not_found;
653 } else {
654 ret = btrfs_search_slot(NULL, root, &key, &path, 0, 0);
655 if (ret < 0)
656 goto err;
657 }
658 if (path.slots[0] >= btrfs_header_nritems(path.nodes[0])) {
659 /*
660 * If btrfs_search_slot() makes path to point beyond nritems,
661 * we should not have an empty leaf, as this inode must at
662 * least have its INODE_ITEM.
663 */
664 ASSERT(btrfs_header_nritems(path.nodes[0]));
665 path.slots[0] = btrfs_header_nritems(path.nodes[0]) - 1;
666 }
667 btrfs_item_key_to_cpu(path.nodes[0], &key, path.slots[0]);
668 /* Perfect match, no need to go one slot back */
669 if (key.objectid == ino && key.type == BTRFS_EXTENT_DATA_KEY &&
670 key.offset == start)
671 goto iterate;
672
673 /* We didn't find a perfect match, needs to go one slot back */
674 if (path.slots[0] > 0) {
675 btrfs_item_key_to_cpu(path.nodes[0], &key, path.slots[0]);
676 if (key.objectid == ino && key.type == BTRFS_EXTENT_DATA_KEY)
677 path.slots[0]--;
678 }
679
680iterate:
681 /* Iterate through the path to find a file extent covering @start */
682 while (true) {
683 u64 extent_end;
684
685 if (path.slots[0] >= btrfs_header_nritems(path.nodes[0]))
686 goto next;
687
688 btrfs_item_key_to_cpu(path.nodes[0], &key, path.slots[0]);
689
690 /*
691 * We may go one slot back to INODE_REF/XATTR item, then
692 * need to go forward until we reach an EXTENT_DATA.
693 * But we should still has the correct ino as key.objectid.
694 */
695 if (WARN_ON(key.objectid < ino) || key.type < BTRFS_EXTENT_DATA_KEY)
696 goto next;
697
698 /* It's beyond our target range, definitely not extent found */
699 if (key.objectid > ino || key.type > BTRFS_EXTENT_DATA_KEY)
700 goto not_found;
701
702 /*
703 * | |<- File extent ->|
704 * \- start
705 *
706 * This means there is a hole between start and key.offset.
707 */
708 if (key.offset > start) {
709 em->start = start;
710 em->orig_start = start;
711 em->block_start = EXTENT_MAP_HOLE;
712 em->len = key.offset - start;
713 break;
714 }
715
716 fi = btrfs_item_ptr(path.nodes[0], path.slots[0],
717 struct btrfs_file_extent_item);
718 extent_end = btrfs_file_extent_end(&path);
719
720 /*
721 * |<- file extent ->| |
722 * \- start
723 *
724 * We haven't reached start, search next slot.
725 */
726 if (extent_end <= start)
727 goto next;
728
729 /* Now this extent covers @start, convert it to em */
730 btrfs_extent_item_to_extent_map(inode, &path, fi, em);
731 break;
732next:
733 ret = btrfs_next_item(root, &path);
734 if (ret < 0)
735 goto err;
736 if (ret > 0)
737 goto not_found;
738 }
739 btrfs_release_path(&path);
740 return em;
741
742not_found:
743 btrfs_release_path(&path);
744 free_extent_map(em);
745 return NULL;
746
747err:
748 btrfs_release_path(&path);
749 free_extent_map(em);
750 return ERR_PTR(ret);
751}
752
753static struct extent_map *defrag_lookup_extent(struct inode *inode, u64 start,
754 u64 newer_than, bool locked)
755{
756 struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
757 struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
758 struct extent_map *em;
759 const u32 sectorsize = BTRFS_I(inode)->root->fs_info->sectorsize;
760
761 /*
762 * Hopefully we have this extent in the tree already, try without the
763 * full extent lock.
764 */
765 read_lock(&em_tree->lock);
766 em = lookup_extent_mapping(em_tree, start, sectorsize);
767 read_unlock(&em_tree->lock);
768
769 /*
770 * We can get a merged extent, in that case, we need to re-search
771 * tree to get the original em for defrag.
772 *
773 * If @newer_than is 0 or em::generation < newer_than, we can trust
774 * this em, as either we don't care about the generation, or the
775 * merged extent map will be rejected anyway.
776 */
777 if (em && (em->flags & EXTENT_FLAG_MERGED) &&
778 newer_than && em->generation >= newer_than) {
779 free_extent_map(em);
780 em = NULL;
781 }
782
783 if (!em) {
784 struct extent_state *cached = NULL;
785 u64 end = start + sectorsize - 1;
786
787 /* Get the big lock and read metadata off disk. */
788 if (!locked)
789 lock_extent(io_tree, start, end, &cached);
790 em = defrag_get_extent(BTRFS_I(inode), start, newer_than);
791 if (!locked)
792 unlock_extent(io_tree, start, end, &cached);
793
794 if (IS_ERR(em))
795 return NULL;
796 }
797
798 return em;
799}
800
801static u32 get_extent_max_capacity(const struct btrfs_fs_info *fs_info,
802 const struct extent_map *em)
803{
804 if (extent_map_is_compressed(em))
805 return BTRFS_MAX_COMPRESSED;
806 return fs_info->max_extent_size;
807}
808
809static bool defrag_check_next_extent(struct inode *inode, struct extent_map *em,
810 u32 extent_thresh, u64 newer_than, bool locked)
811{
812 struct btrfs_fs_info *fs_info = inode_to_fs_info(inode);
813 struct extent_map *next;
814 bool ret = false;
815
816 /* This is the last extent */
817 if (em->start + em->len >= i_size_read(inode))
818 return false;
819
820 /*
821 * Here we need to pass @newer_then when checking the next extent, or
822 * we will hit a case we mark current extent for defrag, but the next
823 * one will not be a target.
824 * This will just cause extra IO without really reducing the fragments.
825 */
826 next = defrag_lookup_extent(inode, em->start + em->len, newer_than, locked);
827 /* No more em or hole */
828 if (!next || next->block_start >= EXTENT_MAP_LAST_BYTE)
829 goto out;
830 if (next->flags & EXTENT_FLAG_PREALLOC)
831 goto out;
832 /*
833 * If the next extent is at its max capacity, defragging current extent
834 * makes no sense, as the total number of extents won't change.
835 */
836 if (next->len >= get_extent_max_capacity(fs_info, em))
837 goto out;
838 /* Skip older extent */
839 if (next->generation < newer_than)
840 goto out;
841 /* Also check extent size */
842 if (next->len >= extent_thresh)
843 goto out;
844
845 ret = true;
846out:
847 free_extent_map(next);
848 return ret;
849}
850
851/*
852 * Prepare one page to be defragged.
853 *
854 * This will ensure:
855 *
856 * - Returned page is locked and has been set up properly.
857 * - No ordered extent exists in the page.
858 * - The page is uptodate.
859 *
860 * NOTE: Caller should also wait for page writeback after the cluster is
861 * prepared, here we don't do writeback wait for each page.
862 */
863static struct folio *defrag_prepare_one_folio(struct btrfs_inode *inode, pgoff_t index)
864{
865 struct address_space *mapping = inode->vfs_inode.i_mapping;
866 gfp_t mask = btrfs_alloc_write_mask(mapping);
867 u64 page_start = (u64)index << PAGE_SHIFT;
868 u64 page_end = page_start + PAGE_SIZE - 1;
869 struct extent_state *cached_state = NULL;
870 struct folio *folio;
871 int ret;
872
873again:
874 folio = __filemap_get_folio(mapping, index,
875 FGP_LOCK | FGP_ACCESSED | FGP_CREAT, mask);
876 if (IS_ERR(folio))
877 return folio;
878
879 /*
880 * Since we can defragment files opened read-only, we can encounter
881 * transparent huge pages here (see CONFIG_READ_ONLY_THP_FOR_FS). We
882 * can't do I/O using huge pages yet, so return an error for now.
883 * Filesystem transparent huge pages are typically only used for
884 * executables that explicitly enable them, so this isn't very
885 * restrictive.
886 */
887 if (folio_test_large(folio)) {
888 folio_unlock(folio);
889 folio_put(folio);
890 return ERR_PTR(-ETXTBSY);
891 }
892
893 ret = set_folio_extent_mapped(folio);
894 if (ret < 0) {
895 folio_unlock(folio);
896 folio_put(folio);
897 return ERR_PTR(ret);
898 }
899
900 /* Wait for any existing ordered extent in the range */
901 while (1) {
902 struct btrfs_ordered_extent *ordered;
903
904 lock_extent(&inode->io_tree, page_start, page_end, &cached_state);
905 ordered = btrfs_lookup_ordered_range(inode, page_start, PAGE_SIZE);
906 unlock_extent(&inode->io_tree, page_start, page_end,
907 &cached_state);
908 if (!ordered)
909 break;
910
911 folio_unlock(folio);
912 btrfs_start_ordered_extent(ordered);
913 btrfs_put_ordered_extent(ordered);
914 folio_lock(folio);
915 /*
916 * We unlocked the folio above, so we need check if it was
917 * released or not.
918 */
919 if (folio->mapping != mapping || !folio->private) {
920 folio_unlock(folio);
921 folio_put(folio);
922 goto again;
923 }
924 }
925
926 /*
927 * Now the page range has no ordered extent any more. Read the page to
928 * make it uptodate.
929 */
930 if (!folio_test_uptodate(folio)) {
931 btrfs_read_folio(NULL, folio);
932 folio_lock(folio);
933 if (folio->mapping != mapping || !folio->private) {
934 folio_unlock(folio);
935 folio_put(folio);
936 goto again;
937 }
938 if (!folio_test_uptodate(folio)) {
939 folio_unlock(folio);
940 folio_put(folio);
941 return ERR_PTR(-EIO);
942 }
943 }
944 return folio;
945}
946
947struct defrag_target_range {
948 struct list_head list;
949 u64 start;
950 u64 len;
951};
952
953/*
954 * Collect all valid target extents.
955 *
956 * @start: file offset to lookup
957 * @len: length to lookup
958 * @extent_thresh: file extent size threshold, any extent size >= this value
959 * will be ignored
960 * @newer_than: only defrag extents newer than this value
961 * @do_compress: whether the defrag is doing compression
962 * if true, @extent_thresh will be ignored and all regular
963 * file extents meeting @newer_than will be targets.
964 * @locked: if the range has already held extent lock
965 * @target_list: list of targets file extents
966 */
967static int defrag_collect_targets(struct btrfs_inode *inode,
968 u64 start, u64 len, u32 extent_thresh,
969 u64 newer_than, bool do_compress,
970 bool locked, struct list_head *target_list,
971 u64 *last_scanned_ret)
972{
973 struct btrfs_fs_info *fs_info = inode->root->fs_info;
974 bool last_is_target = false;
975 u64 cur = start;
976 int ret = 0;
977
978 while (cur < start + len) {
979 struct extent_map *em;
980 struct defrag_target_range *new;
981 bool next_mergeable = true;
982 u64 range_len;
983
984 last_is_target = false;
985 em = defrag_lookup_extent(&inode->vfs_inode, cur, newer_than, locked);
986 if (!em)
987 break;
988
989 /*
990 * If the file extent is an inlined one, we may still want to
991 * defrag it (fallthrough) if it will cause a regular extent.
992 * This is for users who want to convert inline extents to
993 * regular ones through max_inline= mount option.
994 */
995 if (em->block_start == EXTENT_MAP_INLINE &&
996 em->len <= inode->root->fs_info->max_inline)
997 goto next;
998
999 /* Skip holes and preallocated extents. */
1000 if (em->block_start == EXTENT_MAP_HOLE ||
1001 (em->flags & EXTENT_FLAG_PREALLOC))
1002 goto next;
1003
1004 /* Skip older extent */
1005 if (em->generation < newer_than)
1006 goto next;
1007
1008 /* This em is under writeback, no need to defrag */
1009 if (em->generation == (u64)-1)
1010 goto next;
1011
1012 /*
1013 * Our start offset might be in the middle of an existing extent
1014 * map, so take that into account.
1015 */
1016 range_len = em->len - (cur - em->start);
1017 /*
1018 * If this range of the extent map is already flagged for delalloc,
1019 * skip it, because:
1020 *
1021 * 1) We could deadlock later, when trying to reserve space for
1022 * delalloc, because in case we can't immediately reserve space
1023 * the flusher can start delalloc and wait for the respective
1024 * ordered extents to complete. The deadlock would happen
1025 * because we do the space reservation while holding the range
1026 * locked, and starting writeback, or finishing an ordered
1027 * extent, requires locking the range;
1028 *
1029 * 2) If there's delalloc there, it means there's dirty pages for
1030 * which writeback has not started yet (we clean the delalloc
1031 * flag when starting writeback and after creating an ordered
1032 * extent). If we mark pages in an adjacent range for defrag,
1033 * then we will have a larger contiguous range for delalloc,
1034 * very likely resulting in a larger extent after writeback is
1035 * triggered (except in a case of free space fragmentation).
1036 */
1037 if (test_range_bit_exists(&inode->io_tree, cur, cur + range_len - 1,
1038 EXTENT_DELALLOC))
1039 goto next;
1040
1041 /*
1042 * For do_compress case, we want to compress all valid file
1043 * extents, thus no @extent_thresh or mergeable check.
1044 */
1045 if (do_compress)
1046 goto add;
1047
1048 /* Skip too large extent */
1049 if (em->len >= extent_thresh)
1050 goto next;
1051
1052 /*
1053 * Skip extents already at its max capacity, this is mostly for
1054 * compressed extents, which max cap is only 128K.
1055 */
1056 if (em->len >= get_extent_max_capacity(fs_info, em))
1057 goto next;
1058
1059 /*
1060 * Normally there are no more extents after an inline one, thus
1061 * @next_mergeable will normally be false and not defragged.
1062 * So if an inline extent passed all above checks, just add it
1063 * for defrag, and be converted to regular extents.
1064 */
1065 if (em->block_start == EXTENT_MAP_INLINE)
1066 goto add;
1067
1068 next_mergeable = defrag_check_next_extent(&inode->vfs_inode, em,
1069 extent_thresh, newer_than, locked);
1070 if (!next_mergeable) {
1071 struct defrag_target_range *last;
1072
1073 /* Empty target list, no way to merge with last entry */
1074 if (list_empty(target_list))
1075 goto next;
1076 last = list_entry(target_list->prev,
1077 struct defrag_target_range, list);
1078 /* Not mergeable with last entry */
1079 if (last->start + last->len != cur)
1080 goto next;
1081
1082 /* Mergeable, fall through to add it to @target_list. */
1083 }
1084
1085add:
1086 last_is_target = true;
1087 range_len = min(extent_map_end(em), start + len) - cur;
1088 /*
1089 * This one is a good target, check if it can be merged into
1090 * last range of the target list.
1091 */
1092 if (!list_empty(target_list)) {
1093 struct defrag_target_range *last;
1094
1095 last = list_entry(target_list->prev,
1096 struct defrag_target_range, list);
1097 ASSERT(last->start + last->len <= cur);
1098 if (last->start + last->len == cur) {
1099 /* Mergeable, enlarge the last entry */
1100 last->len += range_len;
1101 goto next;
1102 }
1103 /* Fall through to allocate a new entry */
1104 }
1105
1106 /* Allocate new defrag_target_range */
1107 new = kmalloc(sizeof(*new), GFP_NOFS);
1108 if (!new) {
1109 free_extent_map(em);
1110 ret = -ENOMEM;
1111 break;
1112 }
1113 new->start = cur;
1114 new->len = range_len;
1115 list_add_tail(&new->list, target_list);
1116
1117next:
1118 cur = extent_map_end(em);
1119 free_extent_map(em);
1120 }
1121 if (ret < 0) {
1122 struct defrag_target_range *entry;
1123 struct defrag_target_range *tmp;
1124
1125 list_for_each_entry_safe(entry, tmp, target_list, list) {
1126 list_del_init(&entry->list);
1127 kfree(entry);
1128 }
1129 }
1130 if (!ret && last_scanned_ret) {
1131 /*
1132 * If the last extent is not a target, the caller can skip to
1133 * the end of that extent.
1134 * Otherwise, we can only go the end of the specified range.
1135 */
1136 if (!last_is_target)
1137 *last_scanned_ret = max(cur, *last_scanned_ret);
1138 else
1139 *last_scanned_ret = max(start + len, *last_scanned_ret);
1140 }
1141 return ret;
1142}
1143
1144#define CLUSTER_SIZE (SZ_256K)
1145static_assert(PAGE_ALIGNED(CLUSTER_SIZE));
1146
1147/*
1148 * Defrag one contiguous target range.
1149 *
1150 * @inode: target inode
1151 * @target: target range to defrag
1152 * @pages: locked pages covering the defrag range
1153 * @nr_pages: number of locked pages
1154 *
1155 * Caller should ensure:
1156 *
1157 * - Pages are prepared
1158 * Pages should be locked, no ordered extent in the pages range,
1159 * no writeback.
1160 *
1161 * - Extent bits are locked
1162 */
1163static int defrag_one_locked_target(struct btrfs_inode *inode,
1164 struct defrag_target_range *target,
1165 struct folio **folios, int nr_pages,
1166 struct extent_state **cached_state)
1167{
1168 struct btrfs_fs_info *fs_info = inode->root->fs_info;
1169 struct extent_changeset *data_reserved = NULL;
1170 const u64 start = target->start;
1171 const u64 len = target->len;
1172 unsigned long last_index = (start + len - 1) >> PAGE_SHIFT;
1173 unsigned long start_index = start >> PAGE_SHIFT;
1174 unsigned long first_index = folios[0]->index;
1175 int ret = 0;
1176 int i;
1177
1178 ASSERT(last_index - first_index + 1 <= nr_pages);
1179
1180 ret = btrfs_delalloc_reserve_space(inode, &data_reserved, start, len);
1181 if (ret < 0)
1182 return ret;
1183 clear_extent_bit(&inode->io_tree, start, start + len - 1,
1184 EXTENT_DELALLOC | EXTENT_DO_ACCOUNTING |
1185 EXTENT_DEFRAG, cached_state);
1186 set_extent_bit(&inode->io_tree, start, start + len - 1,
1187 EXTENT_DELALLOC | EXTENT_DEFRAG, cached_state);
1188
1189 /* Update the page status */
1190 for (i = start_index - first_index; i <= last_index - first_index; i++) {
1191 folio_clear_checked(folios[i]);
1192 btrfs_folio_clamp_set_dirty(fs_info, folios[i], start, len);
1193 }
1194 btrfs_delalloc_release_extents(inode, len);
1195 extent_changeset_free(data_reserved);
1196
1197 return ret;
1198}
1199
1200static int defrag_one_range(struct btrfs_inode *inode, u64 start, u32 len,
1201 u32 extent_thresh, u64 newer_than, bool do_compress,
1202 u64 *last_scanned_ret)
1203{
1204 struct extent_state *cached_state = NULL;
1205 struct defrag_target_range *entry;
1206 struct defrag_target_range *tmp;
1207 LIST_HEAD(target_list);
1208 struct folio **folios;
1209 const u32 sectorsize = inode->root->fs_info->sectorsize;
1210 u64 last_index = (start + len - 1) >> PAGE_SHIFT;
1211 u64 start_index = start >> PAGE_SHIFT;
1212 unsigned int nr_pages = last_index - start_index + 1;
1213 int ret = 0;
1214 int i;
1215
1216 ASSERT(nr_pages <= CLUSTER_SIZE / PAGE_SIZE);
1217 ASSERT(IS_ALIGNED(start, sectorsize) && IS_ALIGNED(len, sectorsize));
1218
1219 folios = kcalloc(nr_pages, sizeof(struct folio *), GFP_NOFS);
1220 if (!folios)
1221 return -ENOMEM;
1222
1223 /* Prepare all pages */
1224 for (i = 0; i < nr_pages; i++) {
1225 folios[i] = defrag_prepare_one_folio(inode, start_index + i);
1226 if (IS_ERR(folios[i])) {
1227 ret = PTR_ERR(folios[i]);
1228 nr_pages = i;
1229 goto free_folios;
1230 }
1231 }
1232 for (i = 0; i < nr_pages; i++)
1233 folio_wait_writeback(folios[i]);
1234
1235 /* Lock the pages range */
1236 lock_extent(&inode->io_tree, start_index << PAGE_SHIFT,
1237 (last_index << PAGE_SHIFT) + PAGE_SIZE - 1,
1238 &cached_state);
1239 /*
1240 * Now we have a consistent view about the extent map, re-check
1241 * which range really needs to be defragged.
1242 *
1243 * And this time we have extent locked already, pass @locked = true
1244 * so that we won't relock the extent range and cause deadlock.
1245 */
1246 ret = defrag_collect_targets(inode, start, len, extent_thresh,
1247 newer_than, do_compress, true,
1248 &target_list, last_scanned_ret);
1249 if (ret < 0)
1250 goto unlock_extent;
1251
1252 list_for_each_entry(entry, &target_list, list) {
1253 ret = defrag_one_locked_target(inode, entry, folios, nr_pages,
1254 &cached_state);
1255 if (ret < 0)
1256 break;
1257 }
1258
1259 list_for_each_entry_safe(entry, tmp, &target_list, list) {
1260 list_del_init(&entry->list);
1261 kfree(entry);
1262 }
1263unlock_extent:
1264 unlock_extent(&inode->io_tree, start_index << PAGE_SHIFT,
1265 (last_index << PAGE_SHIFT) + PAGE_SIZE - 1,
1266 &cached_state);
1267free_folios:
1268 for (i = 0; i < nr_pages; i++) {
1269 folio_unlock(folios[i]);
1270 folio_put(folios[i]);
1271 }
1272 kfree(folios);
1273 return ret;
1274}
1275
1276static int defrag_one_cluster(struct btrfs_inode *inode,
1277 struct file_ra_state *ra,
1278 u64 start, u32 len, u32 extent_thresh,
1279 u64 newer_than, bool do_compress,
1280 unsigned long *sectors_defragged,
1281 unsigned long max_sectors,
1282 u64 *last_scanned_ret)
1283{
1284 const u32 sectorsize = inode->root->fs_info->sectorsize;
1285 struct defrag_target_range *entry;
1286 struct defrag_target_range *tmp;
1287 LIST_HEAD(target_list);
1288 int ret;
1289
1290 ret = defrag_collect_targets(inode, start, len, extent_thresh,
1291 newer_than, do_compress, false,
1292 &target_list, NULL);
1293 if (ret < 0)
1294 goto out;
1295
1296 list_for_each_entry(entry, &target_list, list) {
1297 u32 range_len = entry->len;
1298
1299 /* Reached or beyond the limit */
1300 if (max_sectors && *sectors_defragged >= max_sectors) {
1301 ret = 1;
1302 break;
1303 }
1304
1305 if (max_sectors)
1306 range_len = min_t(u32, range_len,
1307 (max_sectors - *sectors_defragged) * sectorsize);
1308
1309 /*
1310 * If defrag_one_range() has updated last_scanned_ret,
1311 * our range may already be invalid (e.g. hole punched).
1312 * Skip if our range is before last_scanned_ret, as there is
1313 * no need to defrag the range anymore.
1314 */
1315 if (entry->start + range_len <= *last_scanned_ret)
1316 continue;
1317
1318 if (ra)
1319 page_cache_sync_readahead(inode->vfs_inode.i_mapping,
1320 ra, NULL, entry->start >> PAGE_SHIFT,
1321 ((entry->start + range_len - 1) >> PAGE_SHIFT) -
1322 (entry->start >> PAGE_SHIFT) + 1);
1323 /*
1324 * Here we may not defrag any range if holes are punched before
1325 * we locked the pages.
1326 * But that's fine, it only affects the @sectors_defragged
1327 * accounting.
1328 */
1329 ret = defrag_one_range(inode, entry->start, range_len,
1330 extent_thresh, newer_than, do_compress,
1331 last_scanned_ret);
1332 if (ret < 0)
1333 break;
1334 *sectors_defragged += range_len >>
1335 inode->root->fs_info->sectorsize_bits;
1336 }
1337out:
1338 list_for_each_entry_safe(entry, tmp, &target_list, list) {
1339 list_del_init(&entry->list);
1340 kfree(entry);
1341 }
1342 if (ret >= 0)
1343 *last_scanned_ret = max(*last_scanned_ret, start + len);
1344 return ret;
1345}
1346
1347/*
1348 * Entry point to file defragmentation.
1349 *
1350 * @inode: inode to be defragged
1351 * @ra: readahead state (can be NUL)
1352 * @range: defrag options including range and flags
1353 * @newer_than: minimum transid to defrag
1354 * @max_to_defrag: max number of sectors to be defragged, if 0, the whole inode
1355 * will be defragged.
1356 *
1357 * Return <0 for error.
1358 * Return >=0 for the number of sectors defragged, and range->start will be updated
1359 * to indicate the file offset where next defrag should be started at.
1360 * (Mostly for autodefrag, which sets @max_to_defrag thus we may exit early without
1361 * defragging all the range).
1362 */
1363int btrfs_defrag_file(struct inode *inode, struct file_ra_state *ra,
1364 struct btrfs_ioctl_defrag_range_args *range,
1365 u64 newer_than, unsigned long max_to_defrag)
1366{
1367 struct btrfs_fs_info *fs_info = inode_to_fs_info(inode);
1368 unsigned long sectors_defragged = 0;
1369 u64 isize = i_size_read(inode);
1370 u64 cur;
1371 u64 last_byte;
1372 bool do_compress = (range->flags & BTRFS_DEFRAG_RANGE_COMPRESS);
1373 bool ra_allocated = false;
1374 int compress_type = BTRFS_COMPRESS_ZLIB;
1375 int ret = 0;
1376 u32 extent_thresh = range->extent_thresh;
1377 pgoff_t start_index;
1378
1379 if (isize == 0)
1380 return 0;
1381
1382 if (range->start >= isize)
1383 return -EINVAL;
1384
1385 if (do_compress) {
1386 if (range->compress_type >= BTRFS_NR_COMPRESS_TYPES)
1387 return -EINVAL;
1388 if (range->compress_type)
1389 compress_type = range->compress_type;
1390 }
1391
1392 if (extent_thresh == 0)
1393 extent_thresh = SZ_256K;
1394
1395 if (range->start + range->len > range->start) {
1396 /* Got a specific range */
1397 last_byte = min(isize, range->start + range->len);
1398 } else {
1399 /* Defrag until file end */
1400 last_byte = isize;
1401 }
1402
1403 /* Align the range */
1404 cur = round_down(range->start, fs_info->sectorsize);
1405 last_byte = round_up(last_byte, fs_info->sectorsize) - 1;
1406
1407 /*
1408 * If we were not given a ra, allocate a readahead context. As
1409 * readahead is just an optimization, defrag will work without it so
1410 * we don't error out.
1411 */
1412 if (!ra) {
1413 ra_allocated = true;
1414 ra = kzalloc(sizeof(*ra), GFP_KERNEL);
1415 if (ra)
1416 file_ra_state_init(ra, inode->i_mapping);
1417 }
1418
1419 /*
1420 * Make writeback start from the beginning of the range, so that the
1421 * defrag range can be written sequentially.
1422 */
1423 start_index = cur >> PAGE_SHIFT;
1424 if (start_index < inode->i_mapping->writeback_index)
1425 inode->i_mapping->writeback_index = start_index;
1426
1427 while (cur < last_byte) {
1428 const unsigned long prev_sectors_defragged = sectors_defragged;
1429 u64 last_scanned = cur;
1430 u64 cluster_end;
1431
1432 if (btrfs_defrag_cancelled(fs_info)) {
1433 ret = -EAGAIN;
1434 break;
1435 }
1436
1437 /* We want the cluster end at page boundary when possible */
1438 cluster_end = (((cur >> PAGE_SHIFT) +
1439 (SZ_256K >> PAGE_SHIFT)) << PAGE_SHIFT) - 1;
1440 cluster_end = min(cluster_end, last_byte);
1441
1442 btrfs_inode_lock(BTRFS_I(inode), 0);
1443 if (IS_SWAPFILE(inode)) {
1444 ret = -ETXTBSY;
1445 btrfs_inode_unlock(BTRFS_I(inode), 0);
1446 break;
1447 }
1448 if (!(inode->i_sb->s_flags & SB_ACTIVE)) {
1449 btrfs_inode_unlock(BTRFS_I(inode), 0);
1450 break;
1451 }
1452 if (do_compress)
1453 BTRFS_I(inode)->defrag_compress = compress_type;
1454 ret = defrag_one_cluster(BTRFS_I(inode), ra, cur,
1455 cluster_end + 1 - cur, extent_thresh,
1456 newer_than, do_compress, §ors_defragged,
1457 max_to_defrag, &last_scanned);
1458
1459 if (sectors_defragged > prev_sectors_defragged)
1460 balance_dirty_pages_ratelimited(inode->i_mapping);
1461
1462 btrfs_inode_unlock(BTRFS_I(inode), 0);
1463 if (ret < 0)
1464 break;
1465 cur = max(cluster_end + 1, last_scanned);
1466 if (ret > 0) {
1467 ret = 0;
1468 break;
1469 }
1470 cond_resched();
1471 }
1472
1473 if (ra_allocated)
1474 kfree(ra);
1475 /*
1476 * Update range.start for autodefrag, this will indicate where to start
1477 * in next run.
1478 */
1479 range->start = cur;
1480 if (sectors_defragged) {
1481 /*
1482 * We have defragged some sectors, for compression case they
1483 * need to be written back immediately.
1484 */
1485 if (range->flags & BTRFS_DEFRAG_RANGE_START_IO) {
1486 filemap_flush(inode->i_mapping);
1487 if (test_bit(BTRFS_INODE_HAS_ASYNC_EXTENT,
1488 &BTRFS_I(inode)->runtime_flags))
1489 filemap_flush(inode->i_mapping);
1490 }
1491 if (range->compress_type == BTRFS_COMPRESS_LZO)
1492 btrfs_set_fs_incompat(fs_info, COMPRESS_LZO);
1493 else if (range->compress_type == BTRFS_COMPRESS_ZSTD)
1494 btrfs_set_fs_incompat(fs_info, COMPRESS_ZSTD);
1495 ret = sectors_defragged;
1496 }
1497 if (do_compress) {
1498 btrfs_inode_lock(BTRFS_I(inode), 0);
1499 BTRFS_I(inode)->defrag_compress = BTRFS_COMPRESS_NONE;
1500 btrfs_inode_unlock(BTRFS_I(inode), 0);
1501 }
1502 return ret;
1503}
1504
1505void __cold btrfs_auto_defrag_exit(void)
1506{
1507 kmem_cache_destroy(btrfs_inode_defrag_cachep);
1508}
1509
1510int __init btrfs_auto_defrag_init(void)
1511{
1512 btrfs_inode_defrag_cachep = kmem_cache_create("btrfs_inode_defrag",
1513 sizeof(struct inode_defrag), 0, 0, NULL);
1514 if (!btrfs_inode_defrag_cachep)
1515 return -ENOMEM;
1516
1517 return 0;
1518}