1	// SPDX-License-Identifier: GPL-2.0
2	/*
3	* Copyright (C) 2008 Red Hat. All rights reserved.
4	*/
5
6	#include <linux/pagemap.h>
7	#include <linux/sched.h>
8	#include <linux/sched/signal.h>
9	#include <linux/slab.h>
10	#include <linux/math64.h>
11	#include <linux/ratelimit.h>
12	#include <linux/error-injection.h>
13	#include <linux/sched/mm.h>
14	#include <linux/string_choices.h>
15	#include "extent-tree.h"
16	#include "fs.h"
17	#include "messages.h"
18	#include "misc.h"
19	#include "free-space-cache.h"
20	#include "transaction.h"
21	#include "disk-io.h"
22	#include "extent_io.h"
23	#include "space-info.h"
24	#include "block-group.h"
25	#include "discard.h"
26	#include "subpage.h"
27	#include "inode-item.h"
28	#include "accessors.h"
29	#include "file-item.h"
30	#include "file.h"
31	#include "super.h"
32
33	#define BITS_PER_BITMAP (PAGE_SIZE * 8UL)
34	#define MAX_CACHE_BYTES_PER_GIG SZ_64K
35	#define FORCE_EXTENT_THRESHOLD SZ_1M
36
37	static struct kmem_cache *btrfs_free_space_cachep;
38	static struct kmem_cache *btrfs_free_space_bitmap_cachep;
39
40	struct btrfs_trim_range {
41	u64 start;
42	u64 bytes;
43	struct list_head list;
44	};
45
46	static int link_free_space(struct btrfs_free_space_ctl *ctl,
47	struct btrfs_free_space *info);
48	static void unlink_free_space(struct btrfs_free_space_ctl *ctl,
49	struct btrfs_free_space *info, bool update_stat);
50	static int search_bitmap(struct btrfs_free_space_ctl *ctl,
51	struct btrfs_free_space *bitmap_info, u64 *offset,
52	u64 *bytes, bool for_alloc);
53	static void free_bitmap(struct btrfs_free_space_ctl *ctl,
54	struct btrfs_free_space *bitmap_info);
55	static void bitmap_clear_bits(struct btrfs_free_space_ctl *ctl,
56	struct btrfs_free_space *info, u64 offset,
57	u64 bytes, bool update_stats);
58
59	static void btrfs_crc32c_final(u32 crc, u8 *result)
60	{
61	put_unaligned_le32(val: ~crc, p: result);
62	}
63
64	static void __btrfs_remove_free_space_cache(struct btrfs_free_space_ctl *ctl)
65	{
66	struct btrfs_free_space *info;
67	struct rb_node *node;
68
69	while ((node = rb_last(root: &ctl->free_space_offset)) != NULL) {
70	info = rb_entry(node, struct btrfs_free_space, offset_index);
71	if (!info->bitmap) {
72	unlink_free_space(ctl, info, update_stat: true);
73	kmem_cache_free(s: btrfs_free_space_cachep, objp: info);
74	} else {
75	free_bitmap(ctl, bitmap_info: info);
76	}
77
78	cond_resched_lock(&ctl->tree_lock);
79	}
80	}
81
82	static struct inode *__lookup_free_space_inode(struct btrfs_root *root,
83	struct btrfs_path *path,
84	u64 offset)
85	{
86	struct btrfs_key key;
87	struct btrfs_key location;
88	struct btrfs_disk_key disk_key;
89	struct btrfs_free_space_header *header;
90	struct extent_buffer *leaf;
91	struct btrfs_inode *inode;
92	unsigned nofs_flag;
93	int ret;
94
95	key.objectid = BTRFS_FREE_SPACE_OBJECTID;
96	key.type = 0;
97	key.offset = offset;
98
99	ret = btrfs_search_slot(NULL, root, key: &key, p: path, ins_len: 0, cow: 0);
100	if (ret < 0)
101	return ERR_PTR(error: ret);
102	if (ret > 0) {
103	btrfs_release_path(p: path);
104	return ERR_PTR(error: -ENOENT);
105	}
106
107	leaf = path->nodes[0];
108	header = btrfs_item_ptr(leaf, path->slots[0],
109	struct btrfs_free_space_header);
110	btrfs_free_space_key(eb: leaf, h: header, key: &disk_key);
111	btrfs_disk_key_to_cpu(cpu_key: &location, disk_key: &disk_key);
112	btrfs_release_path(p: path);
113
114	/*
115	* We are often under a trans handle at this point, so we need to make
116	* sure NOFS is set to keep us from deadlocking.
117	*/
118	nofs_flag = memalloc_nofs_save();
119	inode = btrfs_iget_path(ino: location.objectid, root, path);
120	btrfs_release_path(p: path);
121	memalloc_nofs_restore(flags: nofs_flag);
122	if (IS_ERR(ptr: inode))
123	return ERR_CAST(ptr: inode);
124
125	mapping_set_gfp_mask(m: inode->vfs_inode.i_mapping,
126	mask: mapping_gfp_constraint(mapping: inode->vfs_inode.i_mapping,
127	gfp_mask: ~(__GFP_FS | __GFP_HIGHMEM)));
128
129	return &inode->vfs_inode;
130	}
131
132	struct inode *lookup_free_space_inode(struct btrfs_block_group *block_group,
133	struct btrfs_path *path)
134	{
135	struct btrfs_fs_info *fs_info = block_group->fs_info;
136	struct inode *inode = NULL;
137	u32 flags = BTRFS_INODE_NODATASUM | BTRFS_INODE_NODATACOW;
138
139	spin_lock(lock: &block_group->lock);
140	if (block_group->inode)
141	inode = igrab(&block_group->inode->vfs_inode);
142	spin_unlock(lock: &block_group->lock);
143	if (inode)
144	return inode;
145
146	inode = __lookup_free_space_inode(root: fs_info->tree_root, path,
147	offset: block_group->start);
148	if (IS_ERR(ptr: inode))
149	return inode;
150
151	spin_lock(lock: &block_group->lock);
152	if (!((BTRFS_I(inode)->flags & flags) == flags)) {
153	btrfs_info(fs_info, "Old style space inode found, converting.");
154	BTRFS_I(inode)->flags |= BTRFS_INODE_NODATASUM |
155	BTRFS_INODE_NODATACOW;
156	block_group->disk_cache_state = BTRFS_DC_CLEAR;
157	}
158
159	if (!test_and_set_bit(nr: BLOCK_GROUP_FLAG_IREF, addr: &block_group->runtime_flags))
160	block_group->inode = BTRFS_I(igrab(inode));
161	spin_unlock(lock: &block_group->lock);
162
163	return inode;
164	}
165
166	static int __create_free_space_inode(struct btrfs_root *root,
167	struct btrfs_trans_handle *trans,
168	struct btrfs_path *path,
169	u64 ino, u64 offset)
170	{
171	struct btrfs_key key;
172	struct btrfs_disk_key disk_key;
173	struct btrfs_free_space_header *header;
174	struct btrfs_inode_item *inode_item;
175	struct extent_buffer *leaf;
176	/* We inline CRCs for the free disk space cache */
177	const u64 flags = BTRFS_INODE_NOCOMPRESS | BTRFS_INODE_PREALLOC |
178	BTRFS_INODE_NODATASUM | BTRFS_INODE_NODATACOW;
179	int ret;
180
181	ret = btrfs_insert_empty_inode(trans, root, path, objectid: ino);
182	if (ret)
183	return ret;
184
185	leaf = path->nodes[0];
186	inode_item = btrfs_item_ptr(leaf, path->slots[0],
187	struct btrfs_inode_item);
188	btrfs_item_key(eb: leaf, disk_key: &disk_key, nr: path->slots[0]);
189	memzero_extent_buffer(eb: leaf, start: (unsigned long)inode_item,
190	len: sizeof(*inode_item));
191	btrfs_set_inode_generation(eb: leaf, s: inode_item, val: trans->transid);
192	btrfs_set_inode_size(eb: leaf, s: inode_item, val: 0);
193	btrfs_set_inode_nbytes(eb: leaf, s: inode_item, val: 0);
194	btrfs_set_inode_uid(eb: leaf, s: inode_item, val: 0);
195	btrfs_set_inode_gid(eb: leaf, s: inode_item, val: 0);
196	btrfs_set_inode_mode(eb: leaf, s: inode_item, S_IFREG | 0600);
197	btrfs_set_inode_flags(eb: leaf, s: inode_item, val: flags);
198	btrfs_set_inode_nlink(eb: leaf, s: inode_item, val: 1);
199	btrfs_set_inode_transid(eb: leaf, s: inode_item, val: trans->transid);
200	btrfs_set_inode_block_group(eb: leaf, s: inode_item, val: offset);
201	btrfs_release_path(p: path);
202
203	key.objectid = BTRFS_FREE_SPACE_OBJECTID;
204	key.type = 0;
205	key.offset = offset;
206	ret = btrfs_insert_empty_item(trans, root, path, key: &key,
207	data_size: sizeof(struct btrfs_free_space_header));
208	if (ret < 0) {
209	btrfs_release_path(p: path);
210	return ret;
211	}
212
213	leaf = path->nodes[0];
214	header = btrfs_item_ptr(leaf, path->slots[0],
215	struct btrfs_free_space_header);
216	memzero_extent_buffer(eb: leaf, start: (unsigned long)header, len: sizeof(*header));
217	btrfs_set_free_space_key(eb: leaf, h: header, key: &disk_key);
218	btrfs_release_path(p: path);
219
220	return 0;
221	}
222
223	int create_free_space_inode(struct btrfs_trans_handle *trans,
224	struct btrfs_block_group *block_group,
225	struct btrfs_path *path)
226	{
227	int ret;
228	u64 ino;
229
230	ret = btrfs_get_free_objectid(root: trans->fs_info->tree_root, objectid: &ino);
231	if (ret < 0)
232	return ret;
233
234	return __create_free_space_inode(root: trans->fs_info->tree_root, trans, path,
235	ino, offset: block_group->start);
236	}
237
238	/*
239	* inode is an optional sink: if it is NULL, btrfs_remove_free_space_inode
240	* handles lookup, otherwise it takes ownership and iputs the inode.
241	* Don't reuse an inode pointer after passing it into this function.
242	*/
243	int btrfs_remove_free_space_inode(struct btrfs_trans_handle *trans,
244	struct inode *inode,
245	struct btrfs_block_group *block_group)
246	{
247	BTRFS_PATH_AUTO_FREE(path);
248	struct btrfs_key key;
249	int ret = 0;
250
251	path = btrfs_alloc_path();
252	if (!path)
253	return -ENOMEM;
254
255	if (!inode)
256	inode = lookup_free_space_inode(block_group, path);
257	if (IS_ERR(ptr: inode)) {
258	if (PTR_ERR(ptr: inode) != -ENOENT)
259	ret = PTR_ERR(ptr: inode);
260	return ret;
261	}
262	ret = btrfs_orphan_add(trans, BTRFS_I(inode));
263	if (ret) {
264	btrfs_add_delayed_iput(BTRFS_I(inode));
265	return ret;
266	}
267	clear_nlink(inode);
268	/* One for the block groups ref */
269	spin_lock(lock: &block_group->lock);
270	if (test_and_clear_bit(nr: BLOCK_GROUP_FLAG_IREF, addr: &block_group->runtime_flags)) {
271	block_group->inode = NULL;
272	spin_unlock(lock: &block_group->lock);
273	iput(inode);
274	} else {
275	spin_unlock(lock: &block_group->lock);
276	}
277	/* One for the lookup ref */
278	btrfs_add_delayed_iput(BTRFS_I(inode));
279
280	key.objectid = BTRFS_FREE_SPACE_OBJECTID;
281	key.type = 0;
282	key.offset = block_group->start;
283	ret = btrfs_search_slot(trans, root: trans->fs_info->tree_root, key: &key, p: path,
284	ins_len: -1, cow: 1);
285	if (ret) {
286	if (ret > 0)
287	ret = 0;
288	return ret;
289	}
290	return btrfs_del_item(trans, root: trans->fs_info->tree_root, path);
291	}
292
293	int btrfs_truncate_free_space_cache(struct btrfs_trans_handle *trans,
294	struct btrfs_block_group *block_group,
295	struct inode *vfs_inode)
296	{
297	struct btrfs_truncate_control control = {
298	.inode = BTRFS_I(vfs_inode),
299	.new_size = 0,
300	.ino = btrfs_ino(BTRFS_I(vfs_inode)),
301	.min_type = BTRFS_EXTENT_DATA_KEY,
302	.clear_extent_range = true,
303	};
304	struct btrfs_inode *inode = BTRFS_I(vfs_inode);
305	struct btrfs_root *root = inode->root;
306	struct extent_state *cached_state = NULL;
307	int ret = 0;
308	bool locked = false;
309
310	if (block_group) {
311	BTRFS_PATH_AUTO_FREE(path);
312
313	path = btrfs_alloc_path();
314	if (!path) {
315	ret = -ENOMEM;
316	goto fail;
317	}
318	locked = true;
319	mutex_lock(&trans->transaction->cache_write_mutex);
320	if (!list_empty(head: &block_group->io_list)) {
321	list_del_init(entry: &block_group->io_list);
322
323	btrfs_wait_cache_io(trans, block_group, path);
324	btrfs_put_block_group(cache: block_group);
325	}
326
327	/*
328	* now that we've truncated the cache away, its no longer
329	* setup or written
330	*/
331	spin_lock(lock: &block_group->lock);
332	block_group->disk_cache_state = BTRFS_DC_CLEAR;
333	spin_unlock(lock: &block_group->lock);
334	}
335
336	btrfs_i_size_write(inode, size: 0);
337	truncate_pagecache(inode: vfs_inode, new: 0);
338
339	btrfs_lock_extent(tree: &inode->io_tree, start: 0, end: (u64)-1, cached: &cached_state);
340	btrfs_drop_extent_map_range(inode, start: 0, end: (u64)-1, skip_pinned: false);
341
342	/*
343	* We skip the throttling logic for free space cache inodes, so we don't
344	* need to check for -EAGAIN.
345	*/
346	ret = btrfs_truncate_inode_items(trans, root, control: &control);
347
348	inode_sub_bytes(inode: &inode->vfs_inode, bytes: control.sub_bytes);
349	btrfs_inode_safe_disk_i_size_write(inode, new_i_size: control.last_size);
350
351	btrfs_unlock_extent(tree: &inode->io_tree, start: 0, end: (u64)-1, cached: &cached_state);
352	if (ret)
353	goto fail;
354
355	ret = btrfs_update_inode(trans, inode);
356
357	fail:
358	if (locked)
359	mutex_unlock(lock: &trans->transaction->cache_write_mutex);
360	if (ret)
361	btrfs_abort_transaction(trans, ret);
362
363	return ret;
364	}
365
366	static void readahead_cache(struct inode *inode)
367	{
368	struct file_ra_state ra;
369	pgoff_t last_index;
370
371	file_ra_state_init(ra: &ra, mapping: inode->i_mapping);
372	last_index = (i_size_read(inode) - 1) >> PAGE_SHIFT;
373
374	page_cache_sync_readahead(mapping: inode->i_mapping, ra: &ra, NULL, index: 0, req_count: last_index);
375	}
376
377	static int io_ctl_init(struct btrfs_io_ctl *io_ctl, struct inode *inode,
378	int write)
379	{
380	int num_pages;
381
382	num_pages = DIV_ROUND_UP(i_size_read(inode), PAGE_SIZE);
383
384	/* Make sure we can fit our crcs and generation into the first page */
385	if (write && (num_pages * sizeof(u32) + sizeof(u64)) > PAGE_SIZE)
386	return -ENOSPC;
387
388	memset(io_ctl, 0, sizeof(struct btrfs_io_ctl));
389
390	io_ctl->pages = kcalloc(num_pages, sizeof(struct page *), GFP_NOFS);
391	if (!io_ctl->pages)
392	return -ENOMEM;
393
394	io_ctl->num_pages = num_pages;
395	io_ctl->fs_info = inode_to_fs_info(inode);
396	io_ctl->inode = inode;
397
398	return 0;
399	}
400	ALLOW_ERROR_INJECTION(io_ctl_init, ERRNO);
401
402	static void io_ctl_free(struct btrfs_io_ctl *io_ctl)
403	{
404	kfree(objp: io_ctl->pages);
405	io_ctl->pages = NULL;
406	}
407
408	static void io_ctl_unmap_page(struct btrfs_io_ctl *io_ctl)
409	{
410	if (io_ctl->cur) {
411	io_ctl->cur = NULL;
412	io_ctl->orig = NULL;
413	}
414	}
415
416	static void io_ctl_map_page(struct btrfs_io_ctl *io_ctl, int clear)
417	{
418	ASSERT(io_ctl->index < io_ctl->num_pages);
419	io_ctl->page = io_ctl->pages[io_ctl->index++];
420	io_ctl->cur = page_address(io_ctl->page);
421	io_ctl->orig = io_ctl->cur;
422	io_ctl->size = PAGE_SIZE;
423	if (clear)
424	clear_page(page: io_ctl->cur);
425	}
426
427	static void io_ctl_drop_pages(struct btrfs_io_ctl *io_ctl)
428	{
429	int i;
430
431	io_ctl_unmap_page(io_ctl);
432
433	for (i = 0; i < io_ctl->num_pages; i++) {
434	if (io_ctl->pages[i]) {
435	btrfs_folio_clear_checked(fs_info: io_ctl->fs_info,
436	page_folio(io_ctl->pages[i]),
437	start: page_offset(page: io_ctl->pages[i]),
438	PAGE_SIZE);
439	unlock_page(page: io_ctl->pages[i]);
440	put_page(page: io_ctl->pages[i]);
441	}
442	}
443	}
444
445	static int io_ctl_prepare_pages(struct btrfs_io_ctl *io_ctl, bool uptodate)
446	{
447	struct folio *folio;
448	struct inode *inode = io_ctl->inode;
449	gfp_t mask = btrfs_alloc_write_mask(mapping: inode->i_mapping);
450	int i;
451
452	for (i = 0; i < io_ctl->num_pages; i++) {
453	int ret;
454
455	folio = __filemap_get_folio(mapping: inode->i_mapping, index: i,
456	FGP_LOCK | FGP_ACCESSED | FGP_CREAT,
457	gfp: mask);
458	if (IS_ERR(ptr: folio)) {
459	io_ctl_drop_pages(io_ctl);
460	return PTR_ERR(ptr: folio);
461	}
462
463	ret = set_folio_extent_mapped(folio);
464	if (ret < 0) {
465	folio_unlock(folio);
466	folio_put(folio);
467	io_ctl_drop_pages(io_ctl);
468	return ret;
469	}
470
471	io_ctl->pages[i] = &folio->page;
472	if (uptodate && !folio_test_uptodate(folio)) {
473	btrfs_read_folio(NULL, folio);
474	folio_lock(folio);
475	if (folio->mapping != inode->i_mapping) {
476	btrfs_err(BTRFS_I(inode)->root->fs_info,
477	"free space cache page truncated");
478	io_ctl_drop_pages(io_ctl);
479	return -EIO;
480	}
481	if (!folio_test_uptodate(folio)) {
482	btrfs_err(BTRFS_I(inode)->root->fs_info,
483	"error reading free space cache");
484	io_ctl_drop_pages(io_ctl);
485	return -EIO;
486	}
487	}
488	}
489
490	for (i = 0; i < io_ctl->num_pages; i++)
491	clear_page_dirty_for_io(page: io_ctl->pages[i]);
492
493	return 0;
494	}
495
496	static void io_ctl_set_generation(struct btrfs_io_ctl *io_ctl, u64 generation)
497	{
498	io_ctl_map_page(io_ctl, clear: 1);
499
500	/*
501	* Skip the csum areas. If we don't check crcs then we just have a
502	* 64bit chunk at the front of the first page.
503	*/
504	io_ctl->cur += (sizeof(u32) * io_ctl->num_pages);
505	io_ctl->size -= sizeof(u64) + (sizeof(u32) * io_ctl->num_pages);
506
507	put_unaligned_le64(val: generation, p: io_ctl->cur);
508	io_ctl->cur += sizeof(u64);
509	}
510
511	static int io_ctl_check_generation(struct btrfs_io_ctl *io_ctl, u64 generation)
512	{
513	u64 cache_gen;
514
515	/*
516	* Skip the crc area. If we don't check crcs then we just have a 64bit
517	* chunk at the front of the first page.
518	*/
519	io_ctl->cur += sizeof(u32) * io_ctl->num_pages;
520	io_ctl->size -= sizeof(u64) + (sizeof(u32) * io_ctl->num_pages);
521
522	cache_gen = get_unaligned_le64(p: io_ctl->cur);
523	if (cache_gen != generation) {
524	btrfs_err_rl(io_ctl->fs_info,
525	"space cache generation (%llu) does not match inode (%llu)",
526	cache_gen, generation);
527	io_ctl_unmap_page(io_ctl);
528	return -EIO;
529	}
530	io_ctl->cur += sizeof(u64);
531	return 0;
532	}
533
534	static void io_ctl_set_crc(struct btrfs_io_ctl *io_ctl, int index)
535	{
536	u32 *tmp;
537	u32 crc = ~(u32)0;
538	unsigned offset = 0;
539
540	if (index == 0)
541	offset = sizeof(u32) * io_ctl->num_pages;
542
543	crc = crc32c(crc, p: io_ctl->orig + offset, PAGE_SIZE - offset);
544	btrfs_crc32c_final(crc, result: (u8 *)&crc);
545	io_ctl_unmap_page(io_ctl);
546	tmp = page_address(io_ctl->pages[0]);
547	tmp += index;
548	*tmp = crc;
549	}
550
551	static int io_ctl_check_crc(struct btrfs_io_ctl *io_ctl, int index)
552	{
553	u32 *tmp, val;
554	u32 crc = ~(u32)0;
555	unsigned offset = 0;
556
557	if (index == 0)
558	offset = sizeof(u32) * io_ctl->num_pages;
559
560	tmp = page_address(io_ctl->pages[0]);
561	tmp += index;
562	val = *tmp;
563
564	io_ctl_map_page(io_ctl, clear: 0);
565	crc = crc32c(crc, p: io_ctl->orig + offset, PAGE_SIZE - offset);
566	btrfs_crc32c_final(crc, result: (u8 *)&crc);
567	if (val != crc) {
568	btrfs_err_rl(io_ctl->fs_info,
569	"csum mismatch on free space cache");
570	io_ctl_unmap_page(io_ctl);
571	return -EIO;
572	}
573
574	return 0;
575	}
576
577	static int io_ctl_add_entry(struct btrfs_io_ctl *io_ctl, u64 offset, u64 bytes,
578	void *bitmap)
579	{
580	struct btrfs_free_space_entry *entry;
581
582	if (!io_ctl->cur)
583	return -ENOSPC;
584
585	entry = io_ctl->cur;
586	put_unaligned_le64(val: offset, p: &entry->offset);
587	put_unaligned_le64(val: bytes, p: &entry->bytes);
588	entry->type = (bitmap) ? BTRFS_FREE_SPACE_BITMAP :
589	BTRFS_FREE_SPACE_EXTENT;
590	io_ctl->cur += sizeof(struct btrfs_free_space_entry);
591	io_ctl->size -= sizeof(struct btrfs_free_space_entry);
592
593	if (io_ctl->size >= sizeof(struct btrfs_free_space_entry))
594	return 0;
595
596	io_ctl_set_crc(io_ctl, index: io_ctl->index - 1);
597
598	/* No more pages to map */
599	if (io_ctl->index >= io_ctl->num_pages)
600	return 0;
601
602	/* map the next page */
603	io_ctl_map_page(io_ctl, clear: 1);
604	return 0;
605	}
606
607	static int io_ctl_add_bitmap(struct btrfs_io_ctl *io_ctl, void *bitmap)
608	{
609	if (!io_ctl->cur)
610	return -ENOSPC;
611
612	/*
613	* If we aren't at the start of the current page, unmap this one and
614	* map the next one if there is any left.
615	*/
616	if (io_ctl->cur != io_ctl->orig) {
617	io_ctl_set_crc(io_ctl, index: io_ctl->index - 1);
618	if (io_ctl->index >= io_ctl->num_pages)
619	return -ENOSPC;
620	io_ctl_map_page(io_ctl, clear: 0);
621	}
622
623	copy_page(to: io_ctl->cur, from: bitmap);
624	io_ctl_set_crc(io_ctl, index: io_ctl->index - 1);
625	if (io_ctl->index < io_ctl->num_pages)
626	io_ctl_map_page(io_ctl, clear: 0);
627	return 0;
628	}
629
630	static void io_ctl_zero_remaining_pages(struct btrfs_io_ctl *io_ctl)
631	{
632	/*
633	* If we're not on the boundary we know we've modified the page and we
634	* need to crc the page.
635	*/
636	if (io_ctl->cur != io_ctl->orig)
637	io_ctl_set_crc(io_ctl, index: io_ctl->index - 1);
638	else
639	io_ctl_unmap_page(io_ctl);
640
641	while (io_ctl->index < io_ctl->num_pages) {
642	io_ctl_map_page(io_ctl, clear: 1);
643	io_ctl_set_crc(io_ctl, index: io_ctl->index - 1);
644	}
645	}
646
647	static int io_ctl_read_entry(struct btrfs_io_ctl *io_ctl,
648	struct btrfs_free_space *entry, u8 *type)
649	{
650	struct btrfs_free_space_entry *e;
651	int ret;
652
653	if (!io_ctl->cur) {
654	ret = io_ctl_check_crc(io_ctl, index: io_ctl->index);
655	if (ret)
656	return ret;
657	}
658
659	e = io_ctl->cur;
660	entry->offset = get_unaligned_le64(p: &e->offset);
661	entry->bytes = get_unaligned_le64(p: &e->bytes);
662	*type = e->type;
663	io_ctl->cur += sizeof(struct btrfs_free_space_entry);
664	io_ctl->size -= sizeof(struct btrfs_free_space_entry);
665
666	if (io_ctl->size >= sizeof(struct btrfs_free_space_entry))
667	return 0;
668
669	io_ctl_unmap_page(io_ctl);
670
671	return 0;
672	}
673
674	static int io_ctl_read_bitmap(struct btrfs_io_ctl *io_ctl,
675	struct btrfs_free_space *entry)
676	{
677	int ret;
678
679	ret = io_ctl_check_crc(io_ctl, index: io_ctl->index);
680	if (ret)
681	return ret;
682
683	copy_page(to: entry->bitmap, from: io_ctl->cur);
684	io_ctl_unmap_page(io_ctl);
685
686	return 0;
687	}
688
689	static void recalculate_thresholds(struct btrfs_free_space_ctl *ctl)
690	{
691	struct btrfs_block_group *block_group = ctl->block_group;
692	u64 max_bytes;
693	u64 bitmap_bytes;
694	u64 extent_bytes;
695	u64 size = block_group->length;
696	u64 bytes_per_bg = BITS_PER_BITMAP * ctl->unit;
697	u64 max_bitmaps = div64_u64(dividend: size + bytes_per_bg - 1, divisor: bytes_per_bg);
698
699	max_bitmaps = max_t(u64, max_bitmaps, 1);
700
701	if (ctl->total_bitmaps > max_bitmaps)
702	btrfs_err(block_group->fs_info,
703	"invalid free space control: bg start=%llu len=%llu total_bitmaps=%u unit=%u max_bitmaps=%llu bytes_per_bg=%llu",
704	block_group->start, block_group->length,
705	ctl->total_bitmaps, ctl->unit, max_bitmaps,
706	bytes_per_bg);
707	ASSERT(ctl->total_bitmaps <= max_bitmaps);
708
709	/*
710	* We are trying to keep the total amount of memory used per 1GiB of
711	* space to be MAX_CACHE_BYTES_PER_GIG. However, with a reclamation
712	* mechanism of pulling extents >= FORCE_EXTENT_THRESHOLD out of
713	* bitmaps, we may end up using more memory than this.
714	*/
715	if (size < SZ_1G)
716	max_bytes = MAX_CACHE_BYTES_PER_GIG;
717	else
718	max_bytes = MAX_CACHE_BYTES_PER_GIG * div_u64(dividend: size, SZ_1G);
719
720	bitmap_bytes = ctl->total_bitmaps * ctl->unit;
721
722	/*
723	* we want the extent entry threshold to always be at most 1/2 the max
724	* bytes we can have, or whatever is less than that.
725	*/
726	extent_bytes = max_bytes - bitmap_bytes;
727	extent_bytes = min_t(u64, extent_bytes, max_bytes >> 1);
728
729	ctl->extents_thresh =
730	div_u64(dividend: extent_bytes, divisor: sizeof(struct btrfs_free_space));
731	}
732
733	static int __load_free_space_cache(struct btrfs_root *root, struct inode *inode,
734	struct btrfs_free_space_ctl *ctl,
735	struct btrfs_path *path, u64 offset)
736	{
737	struct btrfs_fs_info *fs_info = root->fs_info;
738	struct btrfs_free_space_header *header;
739	struct extent_buffer *leaf;
740	struct btrfs_io_ctl io_ctl;
741	struct btrfs_key key;
742	struct btrfs_free_space *e, *n;
743	LIST_HEAD(bitmaps);
744	u64 num_entries;
745	u64 num_bitmaps;
746	u64 generation;
747	u8 type;
748	int ret = 0;
749
750	/* Nothing in the space cache, goodbye */
751	if (!i_size_read(inode))
752	return 0;
753
754	key.objectid = BTRFS_FREE_SPACE_OBJECTID;
755	key.type = 0;
756	key.offset = offset;
757
758	ret = btrfs_search_slot(NULL, root, key: &key, p: path, ins_len: 0, cow: 0);
759	if (ret < 0)
760	return 0;
761	else if (ret > 0) {
762	btrfs_release_path(p: path);
763	return 0;
764	}
765
766	ret = -1;
767
768	leaf = path->nodes[0];
769	header = btrfs_item_ptr(leaf, path->slots[0],
770	struct btrfs_free_space_header);
771	num_entries = btrfs_free_space_entries(eb: leaf, s: header);
772	num_bitmaps = btrfs_free_space_bitmaps(eb: leaf, s: header);
773	generation = btrfs_free_space_generation(eb: leaf, s: header);
774	btrfs_release_path(p: path);
775
776	if (!BTRFS_I(inode)->generation) {
777	btrfs_info(fs_info,
778	"the free space cache file (%llu) is invalid, skip it",
779	offset);
780	return 0;
781	}
782
783	if (BTRFS_I(inode)->generation != generation) {
784	btrfs_err(fs_info,
785	"free space inode generation (%llu) did not match free space cache generation (%llu)",
786	BTRFS_I(inode)->generation, generation);
787	return 0;
788	}
789
790	if (!num_entries)
791	return 0;
792
793	ret = io_ctl_init(io_ctl: &io_ctl, inode, write: 0);
794	if (ret)
795	return ret;
796
797	readahead_cache(inode);
798
799	ret = io_ctl_prepare_pages(io_ctl: &io_ctl, uptodate: true);
800	if (ret)
801	goto out;
802
803	ret = io_ctl_check_crc(io_ctl: &io_ctl, index: 0);
804	if (ret)
805	goto free_cache;
806
807	ret = io_ctl_check_generation(io_ctl: &io_ctl, generation);
808	if (ret)
809	goto free_cache;
810
811	while (num_entries) {
812	e = kmem_cache_zalloc(btrfs_free_space_cachep,
813	GFP_NOFS);
814	if (!e) {
815	ret = -ENOMEM;
816	goto free_cache;
817	}
818
819	ret = io_ctl_read_entry(io_ctl: &io_ctl, entry: e, type: &type);
820	if (ret) {
821	kmem_cache_free(s: btrfs_free_space_cachep, objp: e);
822	goto free_cache;
823	}
824
825	if (!e->bytes) {
826	ret = -1;
827	kmem_cache_free(s: btrfs_free_space_cachep, objp: e);
828	goto free_cache;
829	}
830
831	if (type == BTRFS_FREE_SPACE_EXTENT) {
832	spin_lock(lock: &ctl->tree_lock);
833	ret = link_free_space(ctl, info: e);
834	spin_unlock(lock: &ctl->tree_lock);
835	if (ret) {
836	btrfs_err(fs_info,
837	"Duplicate entries in free space cache, dumping");
838	kmem_cache_free(s: btrfs_free_space_cachep, objp: e);
839	goto free_cache;
840	}
841	} else {
842	ASSERT(num_bitmaps);
843	num_bitmaps--;
844	e->bitmap = kmem_cache_zalloc(
845	btrfs_free_space_bitmap_cachep, GFP_NOFS);
846	if (!e->bitmap) {
847	ret = -ENOMEM;
848	kmem_cache_free(
849	s: btrfs_free_space_cachep, objp: e);
850	goto free_cache;
851	}
852	spin_lock(lock: &ctl->tree_lock);
853	ret = link_free_space(ctl, info: e);
854	if (ret) {
855	spin_unlock(lock: &ctl->tree_lock);
856	btrfs_err(fs_info,
857	"Duplicate entries in free space cache, dumping");
858	kmem_cache_free(s: btrfs_free_space_bitmap_cachep, objp: e->bitmap);
859	kmem_cache_free(s: btrfs_free_space_cachep, objp: e);
860	goto free_cache;
861	}
862	ctl->total_bitmaps++;
863	recalculate_thresholds(ctl);
864	spin_unlock(lock: &ctl->tree_lock);
865	list_add_tail(new: &e->list, head: &bitmaps);
866	}
867
868	num_entries--;
869	}
870
871	io_ctl_unmap_page(io_ctl: &io_ctl);
872
873	/*
874	* We add the bitmaps at the end of the entries in order that
875	* the bitmap entries are added to the cache.
876	*/
877	list_for_each_entry_safe(e, n, &bitmaps, list) {
878	list_del_init(entry: &e->list);
879	ret = io_ctl_read_bitmap(io_ctl: &io_ctl, entry: e);
880	if (ret)
881	goto free_cache;
882	}
883
884	io_ctl_drop_pages(io_ctl: &io_ctl);
885	ret = 1;
886	out:
887	io_ctl_free(io_ctl: &io_ctl);
888	return ret;
889	free_cache:
890	io_ctl_drop_pages(io_ctl: &io_ctl);
891
892	spin_lock(lock: &ctl->tree_lock);
893	__btrfs_remove_free_space_cache(ctl);
894	spin_unlock(lock: &ctl->tree_lock);
895	goto out;
896	}
897
898	static int copy_free_space_cache(struct btrfs_block_group *block_group,
899	struct btrfs_free_space_ctl *ctl)
900	{
901	struct btrfs_free_space *info;
902	struct rb_node *n;
903	int ret = 0;
904
905	while (!ret && (n = rb_first(root: &ctl->free_space_offset)) != NULL) {
906	info = rb_entry(n, struct btrfs_free_space, offset_index);
907	if (!info->bitmap) {
908	const u64 offset = info->offset;
909	const u64 bytes = info->bytes;
910
911	unlink_free_space(ctl, info, update_stat: true);
912	spin_unlock(lock: &ctl->tree_lock);
913	kmem_cache_free(s: btrfs_free_space_cachep, objp: info);
914	ret = btrfs_add_free_space(block_group, bytenr: offset, size: bytes);
915	spin_lock(lock: &ctl->tree_lock);
916	} else {
917	u64 offset = info->offset;
918	u64 bytes = ctl->unit;
919
920	ret = search_bitmap(ctl, bitmap_info: info, offset: &offset, bytes: &bytes, for_alloc: false);
921	if (ret == 0) {
922	bitmap_clear_bits(ctl, info, offset, bytes, update_stats: true);
923	spin_unlock(lock: &ctl->tree_lock);
924	ret = btrfs_add_free_space(block_group, bytenr: offset,
925	size: bytes);
926	spin_lock(lock: &ctl->tree_lock);
927	} else {
928	free_bitmap(ctl, bitmap_info: info);
929	ret = 0;
930	}
931	}
932	cond_resched_lock(&ctl->tree_lock);
933	}
934	return ret;
935	}
936
937	static struct lock_class_key btrfs_free_space_inode_key;
938
939	int load_free_space_cache(struct btrfs_block_group *block_group)
940	{
941	struct btrfs_fs_info *fs_info = block_group->fs_info;
942	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
943	struct btrfs_free_space_ctl tmp_ctl = {};
944	struct inode *inode;
945	struct btrfs_path *path;
946	int ret = 0;
947	bool matched;
948	u64 used = block_group->used;
949
950	/*
951	* Because we could potentially discard our loaded free space, we want
952	* to load everything into a temporary structure first, and then if it's
953	* valid copy it all into the actual free space ctl.
954	*/
955	btrfs_init_free_space_ctl(block_group, ctl: &tmp_ctl);
956
957	/*
958	* If this block group has been marked to be cleared for one reason or
959	* another then we can't trust the on disk cache, so just return.
960	*/
961	spin_lock(lock: &block_group->lock);
962	if (block_group->disk_cache_state != BTRFS_DC_WRITTEN) {
963	spin_unlock(lock: &block_group->lock);
964	return 0;
965	}
966	spin_unlock(lock: &block_group->lock);
967
968	path = btrfs_alloc_path();
969	if (!path)
970	return 0;
971	path->search_commit_root = true;
972	path->skip_locking = true;
973
974	/*
975	* We must pass a path with search_commit_root set to btrfs_iget in
976	* order to avoid a deadlock when allocating extents for the tree root.
977	*
978	* When we are COWing an extent buffer from the tree root, when looking
979	* for a free extent, at extent-tree.c:find_free_extent(), we can find
980	* block group without its free space cache loaded. When we find one
981	* we must load its space cache which requires reading its free space
982	* cache's inode item from the root tree. If this inode item is located
983	* in the same leaf that we started COWing before, then we end up in
984	* deadlock on the extent buffer (trying to read lock it when we
985	* previously write locked it).
986	*
987	* It's safe to read the inode item using the commit root because
988	* block groups, once loaded, stay in memory forever (until they are
989	* removed) as well as their space caches once loaded. New block groups
990	* once created get their ->cached field set to BTRFS_CACHE_FINISHED so
991	* we will never try to read their inode item while the fs is mounted.
992	*/
993	inode = lookup_free_space_inode(block_group, path);
994	if (IS_ERR(ptr: inode)) {
995	btrfs_free_path(p: path);
996	return 0;
997	}
998
999	/* We may have converted the inode and made the cache invalid. */
1000	spin_lock(lock: &block_group->lock);
1001	if (block_group->disk_cache_state != BTRFS_DC_WRITTEN) {
1002	spin_unlock(lock: &block_group->lock);
1003	btrfs_free_path(p: path);
1004	goto out;
1005	}
1006	spin_unlock(lock: &block_group->lock);
1007
1008	/*
1009	* Reinitialize the class of struct inode's mapping->invalidate_lock for
1010	* free space inodes to prevent false positives related to locks for normal
1011	* inodes.
1012	*/
1013	lockdep_set_class(&(&inode->i_data)->invalidate_lock,
1014	&btrfs_free_space_inode_key);
1015
1016	ret = __load_free_space_cache(root: fs_info->tree_root, inode, ctl: &tmp_ctl,
1017	path, offset: block_group->start);
1018	btrfs_free_path(p: path);
1019	if (ret <= 0)
1020	goto out;
1021
1022	matched = (tmp_ctl.free_space == (block_group->length - used -
1023	block_group->bytes_super));
1024
1025	if (matched) {
1026	spin_lock(lock: &tmp_ctl.tree_lock);
1027	ret = copy_free_space_cache(block_group, ctl: &tmp_ctl);
1028	spin_unlock(lock: &tmp_ctl.tree_lock);
1029	/*
1030	* ret == 1 means we successfully loaded the free space cache,
1031	* so we need to re-set it here.
1032	*/
1033	if (ret == 0)
1034	ret = 1;
1035	} else {
1036	/*
1037	* We need to call the _locked variant so we don't try to update
1038	* the discard counters.
1039	*/
1040	spin_lock(lock: &tmp_ctl.tree_lock);
1041	__btrfs_remove_free_space_cache(ctl: &tmp_ctl);
1042	spin_unlock(lock: &tmp_ctl.tree_lock);
1043	btrfs_warn(fs_info,
1044	"block group %llu has wrong amount of free space",
1045	block_group->start);
1046	ret = -1;
1047	}
1048	out:
1049	if (ret < 0) {
1050	/* This cache is bogus, make sure it gets cleared */
1051	spin_lock(lock: &block_group->lock);
1052	block_group->disk_cache_state = BTRFS_DC_CLEAR;
1053	spin_unlock(lock: &block_group->lock);
1054	ret = 0;
1055
1056	btrfs_warn(fs_info,
1057	"failed to load free space cache for block group %llu, rebuilding it now",
1058	block_group->start);
1059	}
1060
1061	spin_lock(lock: &ctl->tree_lock);
1062	btrfs_discard_update_discardable(block_group);
1063	spin_unlock(lock: &ctl->tree_lock);
1064	iput(inode);
1065	return ret;
1066	}
1067
1068	static noinline_for_stack
1069	int write_cache_extent_entries(struct btrfs_io_ctl *io_ctl,
1070	struct btrfs_free_space_ctl *ctl,
1071	struct btrfs_block_group *block_group,
1072	int *entries, int *bitmaps,
1073	struct list_head *bitmap_list)
1074	{
1075	int ret;
1076	struct btrfs_free_cluster *cluster = NULL;
1077	struct btrfs_free_cluster *cluster_locked = NULL;
1078	struct rb_node *node = rb_first(root: &ctl->free_space_offset);
1079	struct btrfs_trim_range *trim_entry;
1080
1081	/* Get the cluster for this block_group if it exists */
1082	if (block_group && !list_empty(head: &block_group->cluster_list)) {
1083	cluster = list_first_entry(&block_group->cluster_list,
1084	struct btrfs_free_cluster, block_group_list);
1085	}
1086
1087	if (!node && cluster) {
1088	cluster_locked = cluster;
1089	spin_lock(lock: &cluster_locked->lock);
1090	node = rb_first(root: &cluster->root);
1091	cluster = NULL;
1092	}
1093
1094	/* Write out the extent entries */
1095	while (node) {
1096	struct btrfs_free_space *e;
1097
1098	e = rb_entry(node, struct btrfs_free_space, offset_index);
1099	*entries += 1;
1100
1101	ret = io_ctl_add_entry(io_ctl, offset: e->offset, bytes: e->bytes,
1102	bitmap: e->bitmap);
1103	if (ret)
1104	goto fail;
1105
1106	if (e->bitmap) {
1107	list_add_tail(new: &e->list, head: bitmap_list);
1108	*bitmaps += 1;
1109	}
1110	node = rb_next(node);
1111	if (!node && cluster) {
1112	node = rb_first(root: &cluster->root);
1113	cluster_locked = cluster;
1114	spin_lock(lock: &cluster_locked->lock);
1115	cluster = NULL;
1116	}
1117	}
1118	if (cluster_locked) {
1119	spin_unlock(lock: &cluster_locked->lock);
1120	cluster_locked = NULL;
1121	}
1122
1123	/*
1124	* Make sure we don't miss any range that was removed from our rbtree
1125	* because trimming is running. Otherwise after a umount+mount (or crash
1126	* after committing the transaction) we would leak free space and get
1127	* an inconsistent free space cache report from fsck.
1128	*/
1129	list_for_each_entry(trim_entry, &ctl->trimming_ranges, list) {
1130	ret = io_ctl_add_entry(io_ctl, offset: trim_entry->start,
1131	bytes: trim_entry->bytes, NULL);
1132	if (ret)
1133	goto fail;
1134	*entries += 1;
1135	}
1136
1137	return 0;
1138	fail:
1139	if (cluster_locked)
1140	spin_unlock(lock: &cluster_locked->lock);
1141	return -ENOSPC;
1142	}
1143
1144	static noinline_for_stack int
1145	update_cache_item(struct btrfs_trans_handle *trans,
1146	struct btrfs_root *root,
1147	struct inode *inode,
1148	struct btrfs_path *path, u64 offset,
1149	int entries, int bitmaps)
1150	{
1151	struct btrfs_key key;
1152	struct btrfs_free_space_header *header;
1153	struct extent_buffer *leaf;
1154	int ret;
1155
1156	key.objectid = BTRFS_FREE_SPACE_OBJECTID;
1157	key.type = 0;
1158	key.offset = offset;
1159
1160	ret = btrfs_search_slot(trans, root, key: &key, p: path, ins_len: 0, cow: 1);
1161	if (ret < 0) {
1162	btrfs_clear_extent_bit(tree: &BTRFS_I(inode)->io_tree, start: 0, end: inode->i_size - 1,
1163	bits: EXTENT_DELALLOC, NULL);
1164	goto fail;
1165	}
1166	leaf = path->nodes[0];
1167	if (ret > 0) {
1168	struct btrfs_key found_key;
1169	ASSERT(path->slots[0]);
1170	path->slots[0]--;
1171	btrfs_item_key_to_cpu(eb: leaf, cpu_key: &found_key, nr: path->slots[0]);
1172	if (found_key.objectid != BTRFS_FREE_SPACE_OBJECTID ||
1173	found_key.offset != offset) {
1174	btrfs_clear_extent_bit(tree: &BTRFS_I(inode)->io_tree, start: 0,
1175	end: inode->i_size - 1, bits: EXTENT_DELALLOC,
1176	NULL);
1177	btrfs_release_path(p: path);
1178	goto fail;
1179	}
1180	}
1181
1182	BTRFS_I(inode)->generation = trans->transid;
1183	header = btrfs_item_ptr(leaf, path->slots[0],
1184	struct btrfs_free_space_header);
1185	btrfs_set_free_space_entries(eb: leaf, s: header, val: entries);
1186	btrfs_set_free_space_bitmaps(eb: leaf, s: header, val: bitmaps);
1187	btrfs_set_free_space_generation(eb: leaf, s: header, val: trans->transid);
1188	btrfs_release_path(p: path);
1189
1190	return 0;
1191
1192	fail:
1193	return -1;
1194	}
1195
1196	static noinline_for_stack int write_pinned_extent_entries(
1197	struct btrfs_trans_handle *trans,
1198	struct btrfs_block_group *block_group,
1199	struct btrfs_io_ctl *io_ctl,
1200	int *entries)
1201	{
1202	u64 start, extent_start, extent_end, len;
1203	struct extent_io_tree *unpin = NULL;
1204	int ret;
1205
1206	if (!block_group)
1207	return 0;
1208
1209	/*
1210	* We want to add any pinned extents to our free space cache
1211	* so we don't leak the space
1212	*
1213	* We shouldn't have switched the pinned extents yet so this is the
1214	* right one
1215	*/
1216	unpin = &trans->transaction->pinned_extents;
1217
1218	start = block_group->start;
1219
1220	while (start < block_group->start + block_group->length) {
1221	if (!btrfs_find_first_extent_bit(tree: unpin, start,
1222	start_ret: &extent_start, end_ret: &extent_end,
1223	bits: EXTENT_DIRTY, NULL))
1224	return 0;
1225
1226	/* This pinned extent is out of our range */
1227	if (extent_start >= block_group->start + block_group->length)
1228	return 0;
1229
1230	extent_start = max(extent_start, start);
1231	extent_end = min(block_group->start + block_group->length,
1232	extent_end + 1);
1233	len = extent_end - extent_start;
1234
1235	*entries += 1;
1236	ret = io_ctl_add_entry(io_ctl, offset: extent_start, bytes: len, NULL);
1237	if (ret)
1238	return -ENOSPC;
1239
1240	start = extent_end;
1241	}
1242
1243	return 0;
1244	}
1245
1246	static noinline_for_stack int
1247	write_bitmap_entries(struct btrfs_io_ctl *io_ctl, struct list_head *bitmap_list)
1248	{
1249	struct btrfs_free_space *entry, *next;
1250	int ret;
1251
1252	/* Write out the bitmaps */
1253	list_for_each_entry_safe(entry, next, bitmap_list, list) {
1254	ret = io_ctl_add_bitmap(io_ctl, bitmap: entry->bitmap);
1255	if (ret)
1256	return -ENOSPC;
1257	list_del_init(entry: &entry->list);
1258	}
1259
1260	return 0;
1261	}
1262
1263	static int flush_dirty_cache(struct inode *inode)
1264	{
1265	int ret;
1266
1267	ret = btrfs_wait_ordered_range(BTRFS_I(inode), start: 0, len: (u64)-1);
1268	if (ret)
1269	btrfs_clear_extent_bit(tree: &BTRFS_I(inode)->io_tree, start: 0, end: inode->i_size - 1,
1270	bits: EXTENT_DELALLOC, NULL);
1271
1272	return ret;
1273	}
1274
1275	static void noinline_for_stack
1276	cleanup_bitmap_list(struct list_head *bitmap_list)
1277	{
1278	struct btrfs_free_space *entry, *next;
1279
1280	list_for_each_entry_safe(entry, next, bitmap_list, list)
1281	list_del_init(entry: &entry->list);
1282	}
1283
1284	static void noinline_for_stack
1285	cleanup_write_cache_enospc(struct inode *inode,
1286	struct btrfs_io_ctl *io_ctl,
1287	struct extent_state **cached_state)
1288	{
1289	io_ctl_drop_pages(io_ctl);
1290	btrfs_unlock_extent(tree: &BTRFS_I(inode)->io_tree, start: 0, end: i_size_read(inode) - 1,
1291	cached: cached_state);
1292	}
1293
1294	static int __btrfs_wait_cache_io(struct btrfs_root *root,
1295	struct btrfs_trans_handle *trans,
1296	struct btrfs_block_group *block_group,
1297	struct btrfs_io_ctl *io_ctl,
1298	struct btrfs_path *path, u64 offset)
1299	{
1300	int ret;
1301	struct inode *inode = io_ctl->inode;
1302
1303	if (!inode)
1304	return 0;
1305
1306	/* Flush the dirty pages in the cache file. */
1307	ret = flush_dirty_cache(inode);
1308	if (ret)
1309	goto out;
1310
1311	/* Update the cache item to tell everyone this cache file is valid. */
1312	ret = update_cache_item(trans, root, inode, path, offset,
1313	entries: io_ctl->entries, bitmaps: io_ctl->bitmaps);
1314	out:
1315	if (ret) {
1316	invalidate_inode_pages2(mapping: inode->i_mapping);
1317	BTRFS_I(inode)->generation = 0;
1318	if (block_group)
1319	btrfs_debug(root->fs_info,
1320	"failed to write free space cache for block group %llu error %d",
1321	block_group->start, ret);
1322	}
1323	btrfs_update_inode(trans, BTRFS_I(inode));
1324
1325	if (block_group) {
1326	/* the dirty list is protected by the dirty_bgs_lock */
1327	spin_lock(lock: &trans->transaction->dirty_bgs_lock);
1328
1329	/* the disk_cache_state is protected by the block group lock */
1330	spin_lock(lock: &block_group->lock);
1331
1332	/*
1333	* only mark this as written if we didn't get put back on
1334	* the dirty list while waiting for IO. Otherwise our
1335	* cache state won't be right, and we won't get written again
1336	*/
1337	if (!ret && list_empty(head: &block_group->dirty_list))
1338	block_group->disk_cache_state = BTRFS_DC_WRITTEN;
1339	else if (ret)
1340	block_group->disk_cache_state = BTRFS_DC_ERROR;
1341
1342	spin_unlock(lock: &block_group->lock);
1343	spin_unlock(lock: &trans->transaction->dirty_bgs_lock);
1344	io_ctl->inode = NULL;
1345	iput(inode);
1346	}
1347
1348	return ret;
1349
1350	}
1351
1352	int btrfs_wait_cache_io(struct btrfs_trans_handle *trans,
1353	struct btrfs_block_group *block_group,
1354	struct btrfs_path *path)
1355	{
1356	return __btrfs_wait_cache_io(root: block_group->fs_info->tree_root, trans,
1357	block_group, io_ctl: &block_group->io_ctl,
1358	path, offset: block_group->start);
1359	}
1360
1361	/*
1362	* Write out cached info to an inode.
1363	*
1364	* @inode: freespace inode we are writing out
1365	* @ctl: free space cache we are going to write out
1366	* @block_group: block_group for this cache if it belongs to a block_group
1367	* @io_ctl: holds context for the io
1368	* @trans: the trans handle
1369	*
1370	* This function writes out a free space cache struct to disk for quick recovery
1371	* on mount. This will return 0 if it was successful in writing the cache out,
1372	* or an errno if it was not.
1373	*/
1374	static int __btrfs_write_out_cache(struct inode *inode,
1375	struct btrfs_free_space_ctl *ctl,
1376	struct btrfs_block_group *block_group,
1377	struct btrfs_io_ctl *io_ctl,
1378	struct btrfs_trans_handle *trans)
1379	{
1380	struct extent_state *cached_state = NULL;
1381	LIST_HEAD(bitmap_list);
1382	int entries = 0;
1383	int bitmaps = 0;
1384	int ret;
1385	int must_iput = 0;
1386	int i_size;
1387
1388	if (!i_size_read(inode))
1389	return -EIO;
1390
1391	WARN_ON(io_ctl->pages);
1392	ret = io_ctl_init(io_ctl, inode, write: 1);
1393	if (ret)
1394	return ret;
1395
1396	if (block_group && (block_group->flags & BTRFS_BLOCK_GROUP_DATA)) {
1397	down_write(sem: &block_group->data_rwsem);
1398	spin_lock(lock: &block_group->lock);
1399	if (block_group->delalloc_bytes) {
1400	block_group->disk_cache_state = BTRFS_DC_WRITTEN;
1401	spin_unlock(lock: &block_group->lock);
1402	up_write(sem: &block_group->data_rwsem);
1403	BTRFS_I(inode)->generation = 0;
1404	ret = 0;
1405	must_iput = 1;
1406	goto out;
1407	}
1408	spin_unlock(lock: &block_group->lock);
1409	}
1410
1411	/* Lock all pages first so we can lock the extent safely. */
1412	ret = io_ctl_prepare_pages(io_ctl, uptodate: false);
1413	if (ret)
1414	goto out_unlock;
1415
1416	btrfs_lock_extent(tree: &BTRFS_I(inode)->io_tree, start: 0, end: i_size_read(inode) - 1,
1417	cached: &cached_state);
1418
1419	io_ctl_set_generation(io_ctl, generation: trans->transid);
1420
1421	mutex_lock(&ctl->cache_writeout_mutex);
1422	/* Write out the extent entries in the free space cache */
1423	spin_lock(lock: &ctl->tree_lock);
1424	ret = write_cache_extent_entries(io_ctl, ctl,
1425	block_group, entries: &entries, bitmaps: &bitmaps,
1426	bitmap_list: &bitmap_list);
1427	if (ret)
1428	goto out_nospc_locked;
1429
1430	/*
1431	* Some spaces that are freed in the current transaction are pinned,
1432	* they will be added into free space cache after the transaction is
1433	* committed, we shouldn't lose them.
1434	*
1435	* If this changes while we are working we'll get added back to
1436	* the dirty list and redo it. No locking needed
1437	*/
1438	ret = write_pinned_extent_entries(trans, block_group, io_ctl, entries: &entries);
1439	if (ret)
1440	goto out_nospc_locked;
1441
1442	/*
1443	* At last, we write out all the bitmaps and keep cache_writeout_mutex
1444	* locked while doing it because a concurrent trim can be manipulating
1445	* or freeing the bitmap.
1446	*/
1447	ret = write_bitmap_entries(io_ctl, bitmap_list: &bitmap_list);
1448	spin_unlock(lock: &ctl->tree_lock);
1449	mutex_unlock(lock: &ctl->cache_writeout_mutex);
1450	if (ret)
1451	goto out_nospc;
1452
1453	/* Zero out the rest of the pages just to make sure */
1454	io_ctl_zero_remaining_pages(io_ctl);
1455
1456	/* Everything is written out, now we dirty the pages in the file. */
1457	i_size = i_size_read(inode);
1458	for (int i = 0; i < round_up(i_size, PAGE_SIZE) / PAGE_SIZE; i++) {
1459	u64 dirty_start = i * PAGE_SIZE;
1460	u64 dirty_len = min_t(u64, dirty_start + PAGE_SIZE, i_size) - dirty_start;
1461
1462	ret = btrfs_dirty_folio(BTRFS_I(inode), page_folio(io_ctl->pages[i]),
1463	pos: dirty_start, write_bytes: dirty_len, cached: &cached_state, noreserve: false);
1464	if (ret < 0)
1465	goto out_nospc;
1466	}
1467
1468	if (block_group && (block_group->flags & BTRFS_BLOCK_GROUP_DATA))
1469	up_write(sem: &block_group->data_rwsem);
1470	/*
1471	* Release the pages and unlock the extent, we will flush
1472	* them out later
1473	*/
1474	io_ctl_drop_pages(io_ctl);
1475	io_ctl_free(io_ctl);
1476
1477	btrfs_unlock_extent(tree: &BTRFS_I(inode)->io_tree, start: 0, end: i_size_read(inode) - 1,
1478	cached: &cached_state);
1479
1480	/*
1481	* at this point the pages are under IO and we're happy,
1482	* The caller is responsible for waiting on them and updating
1483	* the cache and the inode
1484	*/
1485	io_ctl->entries = entries;
1486	io_ctl->bitmaps = bitmaps;
1487
1488	ret = btrfs_fdatawrite_range(BTRFS_I(inode), start: 0, end: (u64)-1);
1489	if (ret)
1490	goto out;
1491
1492	return 0;
1493
1494	out_nospc_locked:
1495	cleanup_bitmap_list(bitmap_list: &bitmap_list);
1496	spin_unlock(lock: &ctl->tree_lock);
1497	mutex_unlock(lock: &ctl->cache_writeout_mutex);
1498
1499	out_nospc:
1500	cleanup_write_cache_enospc(inode, io_ctl, cached_state: &cached_state);
1501
1502	out_unlock:
1503	if (block_group && (block_group->flags & BTRFS_BLOCK_GROUP_DATA))
1504	up_write(sem: &block_group->data_rwsem);
1505
1506	out:
1507	io_ctl->inode = NULL;
1508	io_ctl_free(io_ctl);
1509	if (ret) {
1510	invalidate_inode_pages2(mapping: inode->i_mapping);
1511	BTRFS_I(inode)->generation = 0;
1512	}
1513	btrfs_update_inode(trans, BTRFS_I(inode));
1514	if (must_iput)
1515	iput(inode);
1516	return ret;
1517	}
1518
1519	int btrfs_write_out_cache(struct btrfs_trans_handle *trans,
1520	struct btrfs_block_group *block_group,
1521	struct btrfs_path *path)
1522	{
1523	struct btrfs_fs_info *fs_info = trans->fs_info;
1524	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
1525	struct inode *inode;
1526	int ret = 0;
1527
1528	spin_lock(lock: &block_group->lock);
1529	if (block_group->disk_cache_state < BTRFS_DC_SETUP) {
1530	spin_unlock(lock: &block_group->lock);
1531	return 0;
1532	}
1533	spin_unlock(lock: &block_group->lock);
1534
1535	inode = lookup_free_space_inode(block_group, path);
1536	if (IS_ERR(ptr: inode))
1537	return 0;
1538
1539	ret = __btrfs_write_out_cache(inode, ctl, block_group,
1540	io_ctl: &block_group->io_ctl, trans);
1541	if (ret) {
1542	btrfs_debug(fs_info,
1543	"failed to write free space cache for block group %llu error %d",
1544	block_group->start, ret);
1545	spin_lock(lock: &block_group->lock);
1546	block_group->disk_cache_state = BTRFS_DC_ERROR;
1547	spin_unlock(lock: &block_group->lock);
1548
1549	block_group->io_ctl.inode = NULL;
1550	iput(inode);
1551	}
1552
1553	/*
1554	* if ret == 0 the caller is expected to call btrfs_wait_cache_io
1555	* to wait for IO and put the inode
1556	*/
1557
1558	return ret;
1559	}
1560
1561	static inline unsigned long offset_to_bit(u64 bitmap_start, u32 unit,
1562	u64 offset)
1563	{
1564	ASSERT(offset >= bitmap_start);
1565	offset -= bitmap_start;
1566	return (unsigned long)(div_u64(dividend: offset, divisor: unit));
1567	}
1568
1569	static inline unsigned long bytes_to_bits(u64 bytes, u32 unit)
1570	{
1571	return (unsigned long)(div_u64(dividend: bytes, divisor: unit));
1572	}
1573
1574	static inline u64 offset_to_bitmap(struct btrfs_free_space_ctl *ctl,
1575	u64 offset)
1576	{
1577	u64 bitmap_start;
1578	u64 bytes_per_bitmap;
1579
1580	bytes_per_bitmap = BITS_PER_BITMAP * ctl->unit;
1581	bitmap_start = offset - ctl->start;
1582	bitmap_start = div64_u64(dividend: bitmap_start, divisor: bytes_per_bitmap);
1583	bitmap_start *= bytes_per_bitmap;
1584	bitmap_start += ctl->start;
1585
1586	return bitmap_start;
1587	}
1588
1589	static int tree_insert_offset(struct btrfs_free_space_ctl *ctl,
1590	struct btrfs_free_cluster *cluster,
1591	struct btrfs_free_space *new_entry)
1592	{
1593	struct rb_root *root;
1594	struct rb_node **p;
1595	struct rb_node *parent = NULL;
1596
1597	lockdep_assert_held(&ctl->tree_lock);
1598
1599	if (cluster) {
1600	lockdep_assert_held(&cluster->lock);
1601	root = &cluster->root;
1602	} else {
1603	root = &ctl->free_space_offset;
1604	}
1605
1606	p = &root->rb_node;
1607
1608	while (*p) {
1609	struct btrfs_free_space *info;
1610
1611	parent = *p;
1612	info = rb_entry(parent, struct btrfs_free_space, offset_index);
1613
1614	if (new_entry->offset < info->offset) {
1615	p = &(*p)->rb_left;
1616	} else if (new_entry->offset > info->offset) {
1617	p = &(*p)->rb_right;
1618	} else {
1619	/*
1620	* we could have a bitmap entry and an extent entry
1621	* share the same offset. If this is the case, we want
1622	* the extent entry to always be found first if we do a
1623	* linear search through the tree, since we want to have
1624	* the quickest allocation time, and allocating from an
1625	* extent is faster than allocating from a bitmap. So
1626	* if we're inserting a bitmap and we find an entry at
1627	* this offset, we want to go right, or after this entry
1628	* logically. If we are inserting an extent and we've
1629	* found a bitmap, we want to go left, or before
1630	* logically.
1631	*/
1632	if (new_entry->bitmap) {
1633	if (info->bitmap) {
1634	WARN_ON_ONCE(1);
1635	return -EEXIST;
1636	}
1637	p = &(*p)->rb_right;
1638	} else {
1639	if (!info->bitmap) {
1640	WARN_ON_ONCE(1);
1641	return -EEXIST;
1642	}
1643	p = &(*p)->rb_left;
1644	}
1645	}
1646	}
1647
1648	rb_link_node(node: &new_entry->offset_index, parent, rb_link: p);
1649	rb_insert_color(&new_entry->offset_index, root);
1650
1651	return 0;
1652	}
1653
1654	/*
1655	* This is a little subtle. We *only* have ->max_extent_size set if we actually
1656	* searched through the bitmap and figured out the largest ->max_extent_size,
1657	* otherwise it's 0. In the case that it's 0 we don't want to tell the
1658	* allocator the wrong thing, we want to use the actual real max_extent_size
1659	* we've found already if it's larger, or we want to use ->bytes.
1660	*
1661	* This matters because find_free_space() will skip entries who's ->bytes is
1662	* less than the required bytes. So if we didn't search down this bitmap, we
1663	* may pick some previous entry that has a smaller ->max_extent_size than we
1664	* have. For example, assume we have two entries, one that has
1665	* ->max_extent_size set to 4K and ->bytes set to 1M. A second entry hasn't set
1666	* ->max_extent_size yet, has ->bytes set to 8K and it's contiguous. We will
1667	* call into find_free_space(), and return with max_extent_size == 4K, because
1668	* that first bitmap entry had ->max_extent_size set, but the second one did
1669	* not. If instead we returned 8K we'd come in searching for 8K, and find the
1670	* 8K contiguous range.
1671	*
1672	* Consider the other case, we have 2 8K chunks in that second entry and still
1673	* don't have ->max_extent_size set. We'll return 16K, and the next time the
1674	* allocator comes in it'll fully search our second bitmap, and this time it'll
1675	* get an uptodate value of 8K as the maximum chunk size. Then we'll get the
1676	* right allocation the next loop through.
1677	*/
1678	static inline u64 get_max_extent_size(const struct btrfs_free_space *entry)
1679	{
1680	if (entry->bitmap && entry->max_extent_size)
1681	return entry->max_extent_size;
1682	return entry->bytes;
1683	}
1684
1685	/*
1686	* We want the largest entry to be leftmost, so this is inverted from what you'd
1687	* normally expect.
1688	*/
1689	static bool entry_less(struct rb_node *node, const struct rb_node *parent)
1690	{
1691	const struct btrfs_free_space *entry, *exist;
1692
1693	entry = rb_entry(node, struct btrfs_free_space, bytes_index);
1694	exist = rb_entry(parent, struct btrfs_free_space, bytes_index);
1695	return get_max_extent_size(entry: exist) < get_max_extent_size(entry);
1696	}
1697
1698	/*
1699	* searches the tree for the given offset.
1700	*
1701	* fuzzy - If this is set, then we are trying to make an allocation, and we just
1702	* want a section that has at least bytes size and comes at or after the given
1703	* offset.
1704	*/
1705	static struct btrfs_free_space *
1706	tree_search_offset(struct btrfs_free_space_ctl *ctl,
1707	u64 offset, int bitmap_only, int fuzzy)
1708	{
1709	struct rb_node *n = ctl->free_space_offset.rb_node;
1710	struct btrfs_free_space *entry = NULL, *prev = NULL;
1711
1712	lockdep_assert_held(&ctl->tree_lock);
1713
1714	/* find entry that is closest to the 'offset' */
1715	while (n) {
1716	entry = rb_entry(n, struct btrfs_free_space, offset_index);
1717	prev = entry;
1718
1719	if (offset < entry->offset)
1720	n = n->rb_left;
1721	else if (offset > entry->offset)
1722	n = n->rb_right;
1723	else
1724	break;
1725
1726	entry = NULL;
1727	}
1728
1729	if (bitmap_only) {
1730	if (!entry)
1731	return NULL;
1732	if (entry->bitmap)
1733	return entry;
1734
1735	/*
1736	* bitmap entry and extent entry may share same offset,
1737	* in that case, bitmap entry comes after extent entry.
1738	*/
1739	n = rb_next(n);
1740	if (!n)
1741	return NULL;
1742	entry = rb_entry(n, struct btrfs_free_space, offset_index);
1743	if (entry->offset != offset)
1744	return NULL;
1745
1746	WARN_ON(!entry->bitmap);
1747	return entry;
1748	} else if (entry) {
1749	if (entry->bitmap) {
1750	/*
1751	* if previous extent entry covers the offset,
1752	* we should return it instead of the bitmap entry
1753	*/
1754	n = rb_prev(&entry->offset_index);
1755	if (n) {
1756	prev = rb_entry(n, struct btrfs_free_space,
1757	offset_index);
1758	if (!prev->bitmap &&
1759	prev->offset + prev->bytes > offset)
1760	entry = prev;
1761	}
1762	}
1763	return entry;
1764	}
1765
1766	if (!prev)
1767	return NULL;
1768
1769	/* find last entry before the 'offset' */
1770	entry = prev;
1771	if (entry->offset > offset) {
1772	n = rb_prev(&entry->offset_index);
1773	if (n) {
1774	entry = rb_entry(n, struct btrfs_free_space,
1775	offset_index);
1776	ASSERT(entry->offset <= offset);
1777	} else {
1778	if (fuzzy)
1779	return entry;
1780	else
1781	return NULL;
1782	}
1783	}
1784
1785	if (entry->bitmap) {
1786	n = rb_prev(&entry->offset_index);
1787	if (n) {
1788	prev = rb_entry(n, struct btrfs_free_space,
1789	offset_index);
1790	if (!prev->bitmap &&
1791	prev->offset + prev->bytes > offset)
1792	return prev;
1793	}
1794	if (entry->offset + BITS_PER_BITMAP * ctl->unit > offset)
1795	return entry;
1796	} else if (entry->offset + entry->bytes > offset)
1797	return entry;
1798
1799	if (!fuzzy)
1800	return NULL;
1801
1802	while (1) {
1803	n = rb_next(&entry->offset_index);
1804	if (!n)
1805	return NULL;
1806	entry = rb_entry(n, struct btrfs_free_space, offset_index);
1807	if (entry->bitmap) {
1808	if (entry->offset + BITS_PER_BITMAP *
1809	ctl->unit > offset)
1810	break;
1811	} else {
1812	if (entry->offset + entry->bytes > offset)
1813	break;
1814	}
1815	}
1816	return entry;
1817	}
1818
1819	static inline void unlink_free_space(struct btrfs_free_space_ctl *ctl,
1820	struct btrfs_free_space *info,
1821	bool update_stat)
1822	{
1823	lockdep_assert_held(&ctl->tree_lock);
1824
1825	rb_erase(&info->offset_index, &ctl->free_space_offset);
1826	rb_erase_cached(node: &info->bytes_index, root: &ctl->free_space_bytes);
1827	ctl->free_extents--;
1828
1829	if (!info->bitmap && !btrfs_free_space_trimmed(info)) {
1830	ctl->discardable_extents[BTRFS_STAT_CURR]--;
1831	ctl->discardable_bytes[BTRFS_STAT_CURR] -= info->bytes;
1832	}
1833
1834	if (update_stat)
1835	ctl->free_space -= info->bytes;
1836	}
1837
1838	static int link_free_space(struct btrfs_free_space_ctl *ctl,
1839	struct btrfs_free_space *info)
1840	{
1841	int ret = 0;
1842
1843	lockdep_assert_held(&ctl->tree_lock);
1844
1845	ASSERT(info->bytes || info->bitmap);
1846	ret = tree_insert_offset(ctl, NULL, new_entry: info);
1847	if (ret)
1848	return ret;
1849
1850	rb_add_cached(node: &info->bytes_index, tree: &ctl->free_space_bytes, less: entry_less);
1851
1852	if (!info->bitmap && !btrfs_free_space_trimmed(info)) {
1853	ctl->discardable_extents[BTRFS_STAT_CURR]++;
1854	ctl->discardable_bytes[BTRFS_STAT_CURR] += info->bytes;
1855	}
1856
1857	ctl->free_space += info->bytes;
1858	ctl->free_extents++;
1859	return ret;
1860	}
1861
1862	static void relink_bitmap_entry(struct btrfs_free_space_ctl *ctl,
1863	struct btrfs_free_space *info)
1864	{
1865	ASSERT(info->bitmap);
1866
1867	/*
1868	* If our entry is empty it's because we're on a cluster and we don't
1869	* want to re-link it into our ctl bytes index.
1870	*/
1871	if (RB_EMPTY_NODE(&info->bytes_index))
1872	return;
1873
1874	lockdep_assert_held(&ctl->tree_lock);
1875
1876	rb_erase_cached(node: &info->bytes_index, root: &ctl->free_space_bytes);
1877	rb_add_cached(node: &info->bytes_index, tree: &ctl->free_space_bytes, less: entry_less);
1878	}
1879
1880	static inline void bitmap_clear_bits(struct btrfs_free_space_ctl *ctl,
1881	struct btrfs_free_space *info,
1882	u64 offset, u64 bytes, bool update_stat)
1883	{
1884	unsigned long start, count, end;
1885	int extent_delta = -1;
1886
1887	start = offset_to_bit(bitmap_start: info->offset, unit: ctl->unit, offset);
1888	count = bytes_to_bits(bytes, unit: ctl->unit);
1889	end = start + count;
1890	ASSERT(end <= BITS_PER_BITMAP);
1891
1892	bitmap_clear(map: info->bitmap, start, nbits: count);
1893
1894	info->bytes -= bytes;
1895	if (info->max_extent_size > ctl->unit)
1896	info->max_extent_size = 0;
1897
1898	relink_bitmap_entry(ctl, info);
1899
1900	if (start && test_bit(start - 1, info->bitmap))
1901	extent_delta++;
1902
1903	if (end < BITS_PER_BITMAP && test_bit(end, info->bitmap))
1904	extent_delta++;
1905
1906	info->bitmap_extents += extent_delta;
1907	if (!btrfs_free_space_trimmed(info)) {
1908	ctl->discardable_extents[BTRFS_STAT_CURR] += extent_delta;
1909	ctl->discardable_bytes[BTRFS_STAT_CURR] -= bytes;
1910	}
1911
1912	if (update_stat)
1913	ctl->free_space -= bytes;
1914	}
1915
1916	static void btrfs_bitmap_set_bits(struct btrfs_free_space_ctl *ctl,
1917	struct btrfs_free_space *info, u64 offset,
1918	u64 bytes)
1919	{
1920	unsigned long start, count, end;
1921	int extent_delta = 1;
1922
1923	start = offset_to_bit(bitmap_start: info->offset, unit: ctl->unit, offset);
1924	count = bytes_to_bits(bytes, unit: ctl->unit);
1925	end = start + count;
1926	ASSERT(end <= BITS_PER_BITMAP);
1927
1928	bitmap_set(map: info->bitmap, start, nbits: count);
1929
1930	/*
1931	* We set some bytes, we have no idea what the max extent size is
1932	* anymore.
1933	*/
1934	info->max_extent_size = 0;
1935	info->bytes += bytes;
1936	ctl->free_space += bytes;
1937
1938	relink_bitmap_entry(ctl, info);
1939
1940	if (start && test_bit(start - 1, info->bitmap))
1941	extent_delta--;
1942
1943	if (end < BITS_PER_BITMAP && test_bit(end, info->bitmap))
1944	extent_delta--;
1945
1946	info->bitmap_extents += extent_delta;
1947	if (!btrfs_free_space_trimmed(info)) {
1948	ctl->discardable_extents[BTRFS_STAT_CURR] += extent_delta;
1949	ctl->discardable_bytes[BTRFS_STAT_CURR] += bytes;
1950	}
1951	}
1952
1953	/*
1954	* If we can not find suitable extent, we will use bytes to record
1955	* the size of the max extent.
1956	*/
1957	static int search_bitmap(struct btrfs_free_space_ctl *ctl,
1958	struct btrfs_free_space *bitmap_info, u64 *offset,
1959	u64 *bytes, bool for_alloc)
1960	{
1961	unsigned long found_bits = 0;
1962	unsigned long max_bits = 0;
1963	unsigned long bits, i;
1964	unsigned long next_zero;
1965	unsigned long extent_bits;
1966
1967	/*
1968	* Skip searching the bitmap if we don't have a contiguous section that
1969	* is large enough for this allocation.
1970	*/
1971	if (for_alloc &&
1972	bitmap_info->max_extent_size &&
1973	bitmap_info->max_extent_size < *bytes) {
1974	*bytes = bitmap_info->max_extent_size;
1975	return -1;
1976	}
1977
1978	i = offset_to_bit(bitmap_start: bitmap_info->offset, unit: ctl->unit,
1979	max_t(u64, *offset, bitmap_info->offset));
1980	bits = bytes_to_bits(bytes: *bytes, unit: ctl->unit);
1981
1982	for_each_set_bit_from(i, bitmap_info->bitmap, BITS_PER_BITMAP) {
1983	if (for_alloc && bits == 1) {
1984	found_bits = 1;
1985	break;
1986	}
1987	next_zero = find_next_zero_bit(addr: bitmap_info->bitmap,
1988	BITS_PER_BITMAP, offset: i);
1989	extent_bits = next_zero - i;
1990	if (extent_bits >= bits) {
1991	found_bits = extent_bits;
1992	break;
1993	} else if (extent_bits > max_bits) {
1994	max_bits = extent_bits;
1995	}
1996	i = next_zero;
1997	}
1998
1999	if (found_bits) {
2000	*offset = (u64)(i * ctl->unit) + bitmap_info->offset;
2001	*bytes = (u64)(found_bits) * ctl->unit;
2002	return 0;
2003	}
2004
2005	*bytes = (u64)(max_bits) * ctl->unit;
2006	bitmap_info->max_extent_size = *bytes;
2007	relink_bitmap_entry(ctl, info: bitmap_info);
2008	return -1;
2009	}
2010
2011	/* Cache the size of the max extent in bytes */
2012	static struct btrfs_free_space *
2013	find_free_space(struct btrfs_free_space_ctl *ctl, u64 *offset, u64 *bytes,
2014	unsigned long align, u64 *max_extent_size, bool use_bytes_index)
2015	{
2016	struct btrfs_free_space *entry;
2017	struct rb_node *node;
2018	u64 tmp;
2019	u64 align_off;
2020	int ret;
2021
2022	if (!ctl->free_space_offset.rb_node)
2023	goto out;
2024	again:
2025	if (use_bytes_index) {
2026	node = rb_first_cached(&ctl->free_space_bytes);
2027	} else {
2028	entry = tree_search_offset(ctl, offset: offset_to_bitmap(ctl, offset: *offset),
2029	bitmap_only: 0, fuzzy: 1);
2030	if (!entry)
2031	goto out;
2032	node = &entry->offset_index;
2033	}
2034
2035	for (; node; node = rb_next(node)) {
2036	if (use_bytes_index)
2037	entry = rb_entry(node, struct btrfs_free_space,
2038	bytes_index);
2039	else
2040	entry = rb_entry(node, struct btrfs_free_space,
2041	offset_index);
2042
2043	/*
2044	* If we are using the bytes index then all subsequent entries
2045	* in this tree are going to be < bytes, so simply set the max
2046	* extent size and exit the loop.
2047	*
2048	* If we're using the offset index then we need to keep going
2049	* through the rest of the tree.
2050	*/
2051	if (entry->bytes < *bytes) {
2052	*max_extent_size = max(get_max_extent_size(entry),
2053	*max_extent_size);
2054	if (use_bytes_index)
2055	break;
2056	continue;
2057	}
2058
2059	/* make sure the space returned is big enough
2060	* to match our requested alignment
2061	*/
2062	if (*bytes >= align) {
2063	tmp = entry->offset - ctl->start + align - 1;
2064	tmp = div64_u64(dividend: tmp, divisor: align);
2065	tmp = tmp * align + ctl->start;
2066	align_off = tmp - entry->offset;
2067	} else {
2068	align_off = 0;
2069	tmp = entry->offset;
2070	}
2071
2072	/*
2073	* We don't break here if we're using the bytes index because we
2074	* may have another entry that has the correct alignment that is
2075	* the right size, so we don't want to miss that possibility.
2076	* At worst this adds another loop through the logic, but if we
2077	* broke here we could prematurely ENOSPC.
2078	*/
2079	if (entry->bytes < *bytes + align_off) {
2080	*max_extent_size = max(get_max_extent_size(entry),
2081	*max_extent_size);
2082	continue;
2083	}
2084
2085	if (entry->bitmap) {
2086	struct rb_node *old_next = rb_next(node);
2087	u64 size = *bytes;
2088
2089	ret = search_bitmap(ctl, bitmap_info: entry, offset: &tmp, bytes: &size, for_alloc: true);
2090	if (!ret) {
2091	*offset = tmp;
2092	*bytes = size;
2093	return entry;
2094	} else {
2095	*max_extent_size =
2096	max(get_max_extent_size(entry),
2097	*max_extent_size);
2098	}
2099
2100	/*
2101	* The bitmap may have gotten re-arranged in the space
2102	* index here because the max_extent_size may have been
2103	* updated. Start from the beginning again if this
2104	* happened.
2105	*/
2106	if (use_bytes_index && old_next != rb_next(node))
2107	goto again;
2108	continue;
2109	}
2110
2111	*offset = tmp;
2112	*bytes = entry->bytes - align_off;
2113	return entry;
2114	}
2115	out:
2116	return NULL;
2117	}
2118
2119	static void add_new_bitmap(struct btrfs_free_space_ctl *ctl,
2120	struct btrfs_free_space *info, u64 offset)
2121	{
2122	info->offset = offset_to_bitmap(ctl, offset);
2123	info->bytes = 0;
2124	info->bitmap_extents = 0;
2125	INIT_LIST_HEAD(list: &info->list);
2126	link_free_space(ctl, info);
2127	ctl->total_bitmaps++;
2128	recalculate_thresholds(ctl);
2129	}
2130
2131	static void free_bitmap(struct btrfs_free_space_ctl *ctl,
2132	struct btrfs_free_space *bitmap_info)
2133	{
2134	/*
2135	* Normally when this is called, the bitmap is completely empty. However,
2136	* if we are blowing up the free space cache for one reason or another
2137	* via __btrfs_remove_free_space_cache(), then it may not be freed and
2138	* we may leave stats on the table.
2139	*/
2140	if (bitmap_info->bytes && !btrfs_free_space_trimmed(info: bitmap_info)) {
2141	ctl->discardable_extents[BTRFS_STAT_CURR] -=
2142	bitmap_info->bitmap_extents;
2143	ctl->discardable_bytes[BTRFS_STAT_CURR] -= bitmap_info->bytes;
2144
2145	}
2146	unlink_free_space(ctl, info: bitmap_info, update_stat: true);
2147	kmem_cache_free(s: btrfs_free_space_bitmap_cachep, objp: bitmap_info->bitmap);
2148	kmem_cache_free(s: btrfs_free_space_cachep, objp: bitmap_info);
2149	ctl->total_bitmaps--;
2150	recalculate_thresholds(ctl);
2151	}
2152
2153	static noinline int remove_from_bitmap(struct btrfs_free_space_ctl *ctl,
2154	struct btrfs_free_space *bitmap_info,
2155	u64 *offset, u64 *bytes)
2156	{
2157	u64 end;
2158	u64 search_start, search_bytes;
2159	int ret;
2160
2161	again:
2162	end = bitmap_info->offset + (u64)(BITS_PER_BITMAP * ctl->unit) - 1;
2163
2164	/*
2165	* We need to search for bits in this bitmap. We could only cover some
2166	* of the extent in this bitmap thanks to how we add space, so we need
2167	* to search for as much as it as we can and clear that amount, and then
2168	* go searching for the next bit.
2169	*/
2170	search_start = *offset;
2171	search_bytes = ctl->unit;
2172	search_bytes = min(search_bytes, end - search_start + 1);
2173	ret = search_bitmap(ctl, bitmap_info, offset: &search_start, bytes: &search_bytes,
2174	for_alloc: false);
2175	if (ret < 0 || search_start != *offset)
2176	return -EINVAL;
2177
2178	/* We may have found more bits than what we need */
2179	search_bytes = min(search_bytes, *bytes);
2180
2181	/* Cannot clear past the end of the bitmap */
2182	search_bytes = min(search_bytes, end - search_start + 1);
2183
2184	bitmap_clear_bits(ctl, info: bitmap_info, offset: search_start, bytes: search_bytes, update_stat: true);
2185	*offset += search_bytes;
2186	*bytes -= search_bytes;
2187
2188	if (*bytes) {
2189	struct rb_node *next = rb_next(&bitmap_info->offset_index);
2190	if (!bitmap_info->bytes)
2191	free_bitmap(ctl, bitmap_info);
2192
2193	/*
2194	* no entry after this bitmap, but we still have bytes to
2195	* remove, so something has gone wrong.
2196	*/
2197	if (!next)
2198	return -EINVAL;
2199
2200	bitmap_info = rb_entry(next, struct btrfs_free_space,
2201	offset_index);
2202
2203	/*
2204	* if the next entry isn't a bitmap we need to return to let the
2205	* extent stuff do its work.
2206	*/
2207	if (!bitmap_info->bitmap)
2208	return -EAGAIN;
2209
2210	/*
2211	* Ok the next item is a bitmap, but it may not actually hold
2212	* the information for the rest of this free space stuff, so
2213	* look for it, and if we don't find it return so we can try
2214	* everything over again.
2215	*/
2216	search_start = *offset;
2217	search_bytes = ctl->unit;
2218	ret = search_bitmap(ctl, bitmap_info, offset: &search_start,
2219	bytes: &search_bytes, for_alloc: false);
2220	if (ret < 0 || search_start != *offset)
2221	return -EAGAIN;
2222
2223	goto again;
2224	} else if (!bitmap_info->bytes)
2225	free_bitmap(ctl, bitmap_info);
2226
2227	return 0;
2228	}
2229
2230	static u64 add_bytes_to_bitmap(struct btrfs_free_space_ctl *ctl,
2231	struct btrfs_free_space *info, u64 offset,
2232	u64 bytes, enum btrfs_trim_state trim_state)
2233	{
2234	u64 bytes_to_set = 0;
2235	u64 end;
2236
2237	/*
2238	* This is a tradeoff to make bitmap trim state minimal. We mark the
2239	* whole bitmap untrimmed if at any point we add untrimmed regions.
2240	*/
2241	if (trim_state == BTRFS_TRIM_STATE_UNTRIMMED) {
2242	if (btrfs_free_space_trimmed(info)) {
2243	ctl->discardable_extents[BTRFS_STAT_CURR] +=
2244	info->bitmap_extents;
2245	ctl->discardable_bytes[BTRFS_STAT_CURR] += info->bytes;
2246	}
2247	info->trim_state = BTRFS_TRIM_STATE_UNTRIMMED;
2248	}
2249
2250	end = info->offset + (u64)(BITS_PER_BITMAP * ctl->unit);
2251
2252	bytes_to_set = min(end - offset, bytes);
2253
2254	btrfs_bitmap_set_bits(ctl, info, offset, bytes: bytes_to_set);
2255
2256	return bytes_to_set;
2257
2258	}
2259
2260	static bool use_bitmap(struct btrfs_free_space_ctl *ctl,
2261	struct btrfs_free_space *info)
2262	{
2263	struct btrfs_block_group *block_group = ctl->block_group;
2264	struct btrfs_fs_info *fs_info = block_group->fs_info;
2265	bool forced = false;
2266
2267	#ifdef CONFIG_BTRFS_DEBUG
2268	if (btrfs_should_fragment_free_space(block_group))
2269	forced = true;
2270	#endif
2271
2272	/* This is a way to reclaim large regions from the bitmaps. */
2273	if (!forced && info->bytes >= FORCE_EXTENT_THRESHOLD)
2274	return false;
2275
2276	/*
2277	* If we are below the extents threshold then we can add this as an
2278	* extent, and don't have to deal with the bitmap
2279	*/
2280	if (!forced && ctl->free_extents < ctl->extents_thresh) {
2281	/*
2282	* If this block group has some small extents we don't want to
2283	* use up all of our free slots in the cache with them, we want
2284	* to reserve them to larger extents, however if we have plenty
2285	* of cache left then go ahead and add them, no sense in adding
2286	* the overhead of a bitmap if we don't have to.
2287	*/
2288	if (info->bytes <= fs_info->sectorsize * 8) {
2289	if (ctl->free_extents * 3 <= ctl->extents_thresh)
2290	return false;
2291	} else {
2292	return false;
2293	}
2294	}
2295
2296	/*
2297	* The original block groups from mkfs can be really small, like 8
2298	* megabytes, so don't bother with a bitmap for those entries. However
2299	* some block groups can be smaller than what a bitmap would cover but
2300	* are still large enough that they could overflow the 32k memory limit,
2301	* so allow those block groups to still be allowed to have a bitmap
2302	* entry.
2303	*/
2304	if (((BITS_PER_BITMAP * ctl->unit) >> 1) > block_group->length)
2305	return false;
2306
2307	return true;
2308	}
2309
2310	static const struct btrfs_free_space_op free_space_op = {
2311	.use_bitmap = use_bitmap,
2312	};
2313
2314	static int insert_into_bitmap(struct btrfs_free_space_ctl *ctl,
2315	struct btrfs_free_space *info)
2316	{
2317	struct btrfs_free_space *bitmap_info;
2318	struct btrfs_block_group *block_group = NULL;
2319	int added = 0;
2320	u64 bytes, offset, bytes_added;
2321	enum btrfs_trim_state trim_state;
2322	int ret;
2323
2324	bytes = info->bytes;
2325	offset = info->offset;
2326	trim_state = info->trim_state;
2327
2328	if (!ctl->op->use_bitmap(ctl, info))
2329	return 0;
2330
2331	if (ctl->op == &free_space_op)
2332	block_group = ctl->block_group;
2333	again:
2334	/*
2335	* Since we link bitmaps right into the cluster we need to see if we
2336	* have a cluster here, and if so and it has our bitmap we need to add
2337	* the free space to that bitmap.
2338	*/
2339	if (block_group && !list_empty(head: &block_group->cluster_list)) {
2340	struct btrfs_free_cluster *cluster;
2341	struct rb_node *node;
2342	struct btrfs_free_space *entry;
2343
2344	cluster = list_first_entry(&block_group->cluster_list,
2345	struct btrfs_free_cluster, block_group_list);
2346	spin_lock(lock: &cluster->lock);
2347	node = rb_first(root: &cluster->root);
2348	if (!node) {
2349	spin_unlock(lock: &cluster->lock);
2350	goto no_cluster_bitmap;
2351	}
2352
2353	entry = rb_entry(node, struct btrfs_free_space, offset_index);
2354	if (!entry->bitmap) {
2355	spin_unlock(lock: &cluster->lock);
2356	goto no_cluster_bitmap;
2357	}
2358
2359	if (entry->offset == offset_to_bitmap(ctl, offset)) {
2360	bytes_added = add_bytes_to_bitmap(ctl, info: entry, offset,
2361	bytes, trim_state);
2362	bytes -= bytes_added;
2363	offset += bytes_added;
2364	}
2365	spin_unlock(lock: &cluster->lock);
2366	if (!bytes) {
2367	ret = 1;
2368	goto out;
2369	}
2370	}
2371
2372	no_cluster_bitmap:
2373	bitmap_info = tree_search_offset(ctl, offset: offset_to_bitmap(ctl, offset),
2374	bitmap_only: 1, fuzzy: 0);
2375	if (!bitmap_info) {
2376	ASSERT(added == 0);
2377	goto new_bitmap;
2378	}
2379
2380	bytes_added = add_bytes_to_bitmap(ctl, info: bitmap_info, offset, bytes,
2381	trim_state);
2382	bytes -= bytes_added;
2383	offset += bytes_added;
2384	added = 0;
2385
2386	if (!bytes) {
2387	ret = 1;
2388	goto out;
2389	} else
2390	goto again;
2391
2392	new_bitmap:
2393	if (info && info->bitmap) {
2394	add_new_bitmap(ctl, info, offset);
2395	added = 1;
2396	info = NULL;
2397	goto again;
2398	} else {
2399	spin_unlock(lock: &ctl->tree_lock);
2400
2401	/* no pre-allocated info, allocate a new one */
2402	if (!info) {
2403	info = kmem_cache_zalloc(btrfs_free_space_cachep,
2404	GFP_NOFS);
2405	if (!info) {
2406	spin_lock(lock: &ctl->tree_lock);
2407	ret = -ENOMEM;
2408	goto out;
2409	}
2410	}
2411
2412	/* allocate the bitmap */
2413	info->bitmap = kmem_cache_zalloc(btrfs_free_space_bitmap_cachep,
2414	GFP_NOFS);
2415	info->trim_state = BTRFS_TRIM_STATE_TRIMMED;
2416	spin_lock(lock: &ctl->tree_lock);
2417	if (!info->bitmap) {
2418	ret = -ENOMEM;
2419	goto out;
2420	}
2421	goto again;
2422	}
2423
2424	out:
2425	if (info) {
2426	if (info->bitmap)
2427	kmem_cache_free(s: btrfs_free_space_bitmap_cachep,
2428	objp: info->bitmap);
2429	kmem_cache_free(s: btrfs_free_space_cachep, objp: info);
2430	}
2431
2432	return ret;
2433	}
2434
2435	/*
2436	* Free space merging rules:
2437	* 1) Merge trimmed areas together
2438	* 2) Let untrimmed areas coalesce with trimmed areas
2439	* 3) Always pull neighboring regions from bitmaps
2440	*
2441	* The above rules are for when we merge free space based on btrfs_trim_state.
2442	* Rules 2 and 3 are subtle because they are suboptimal, but are done for the
2443	* same reason: to promote larger extent regions which makes life easier for
2444	* find_free_extent(). Rule 2 enables coalescing based on the common path
2445	* being returning free space from btrfs_finish_extent_commit(). So when free
2446	* space is trimmed, it will prevent aggregating trimmed new region and
2447	* untrimmed regions in the rb_tree. Rule 3 is purely to obtain larger extents
2448	* and provide find_free_extent() with the largest extents possible hoping for
2449	* the reuse path.
2450	*/
2451	static bool try_merge_free_space(struct btrfs_free_space_ctl *ctl,
2452	struct btrfs_free_space *info, bool update_stat)
2453	{
2454	struct btrfs_free_space *left_info = NULL;
2455	struct btrfs_free_space *right_info;
2456	bool merged = false;
2457	u64 offset = info->offset;
2458	u64 bytes = info->bytes;
2459	const bool is_trimmed = btrfs_free_space_trimmed(info);
2460	struct rb_node *right_prev = NULL;
2461
2462	/*
2463	* first we want to see if there is free space adjacent to the range we
2464	* are adding, if there is remove that struct and add a new one to
2465	* cover the entire range
2466	*/
2467	right_info = tree_search_offset(ctl, offset: offset + bytes, bitmap_only: 0, fuzzy: 0);
2468	if (right_info)
2469	right_prev = rb_prev(&right_info->offset_index);
2470
2471	if (right_prev)
2472	left_info = rb_entry(right_prev, struct btrfs_free_space, offset_index);
2473	else if (!right_info)
2474	left_info = tree_search_offset(ctl, offset: offset - 1, bitmap_only: 0, fuzzy: 0);
2475
2476	/* See try_merge_free_space() comment. */
2477	if (right_info && !right_info->bitmap &&
2478	(!is_trimmed || btrfs_free_space_trimmed(info: right_info))) {
2479	unlink_free_space(ctl, info: right_info, update_stat);
2480	info->bytes += right_info->bytes;
2481	kmem_cache_free(s: btrfs_free_space_cachep, objp: right_info);
2482	merged = true;
2483	}
2484
2485	/* See try_merge_free_space() comment. */
2486	if (left_info && !left_info->bitmap &&
2487	left_info->offset + left_info->bytes == offset &&
2488	(!is_trimmed || btrfs_free_space_trimmed(info: left_info))) {
2489	unlink_free_space(ctl, info: left_info, update_stat);
2490	info->offset = left_info->offset;
2491	info->bytes += left_info->bytes;
2492	kmem_cache_free(s: btrfs_free_space_cachep, objp: left_info);
2493	merged = true;
2494	}
2495
2496	return merged;
2497	}
2498
2499	static bool steal_from_bitmap_to_end(struct btrfs_free_space_ctl *ctl,
2500	struct btrfs_free_space *info,
2501	bool update_stat)
2502	{
2503	struct btrfs_free_space *bitmap;
2504	unsigned long i;
2505	unsigned long j;
2506	const u64 end = info->offset + info->bytes;
2507	const u64 bitmap_offset = offset_to_bitmap(ctl, offset: end);
2508	u64 bytes;
2509
2510	bitmap = tree_search_offset(ctl, offset: bitmap_offset, bitmap_only: 1, fuzzy: 0);
2511	if (!bitmap)
2512	return false;
2513
2514	i = offset_to_bit(bitmap_start: bitmap->offset, unit: ctl->unit, offset: end);
2515	j = find_next_zero_bit(addr: bitmap->bitmap, BITS_PER_BITMAP, offset: i);
2516	if (j == i)
2517	return false;
2518	bytes = (j - i) * ctl->unit;
2519	info->bytes += bytes;
2520
2521	/* See try_merge_free_space() comment. */
2522	if (!btrfs_free_space_trimmed(info: bitmap))
2523	info->trim_state = BTRFS_TRIM_STATE_UNTRIMMED;
2524
2525	bitmap_clear_bits(ctl, info: bitmap, offset: end, bytes, update_stat);
2526
2527	if (!bitmap->bytes)
2528	free_bitmap(ctl, bitmap_info: bitmap);
2529
2530	return true;
2531	}
2532
2533	static bool steal_from_bitmap_to_front(struct btrfs_free_space_ctl *ctl,
2534	struct btrfs_free_space *info,
2535	bool update_stat)
2536	{
2537	struct btrfs_free_space *bitmap;
2538	u64 bitmap_offset;
2539	unsigned long i;
2540	unsigned long j;
2541	unsigned long prev_j;
2542	u64 bytes;
2543
2544	bitmap_offset = offset_to_bitmap(ctl, offset: info->offset);
2545	/* If we're on a boundary, try the previous logical bitmap. */
2546	if (bitmap_offset == info->offset) {
2547	if (info->offset == 0)
2548	return false;
2549	bitmap_offset = offset_to_bitmap(ctl, offset: info->offset - 1);
2550	}
2551
2552	bitmap = tree_search_offset(ctl, offset: bitmap_offset, bitmap_only: 1, fuzzy: 0);
2553	if (!bitmap)
2554	return false;
2555
2556	i = offset_to_bit(bitmap_start: bitmap->offset, unit: ctl->unit, offset: info->offset) - 1;
2557	j = 0;
2558	prev_j = (unsigned long)-1;
2559	for_each_clear_bit_from(j, bitmap->bitmap, BITS_PER_BITMAP) {
2560	if (j > i)
2561	break;
2562	prev_j = j;
2563	}
2564	if (prev_j == i)
2565	return false;
2566
2567	if (prev_j == (unsigned long)-1)
2568	bytes = (i + 1) * ctl->unit;
2569	else
2570	bytes = (i - prev_j) * ctl->unit;
2571
2572	info->offset -= bytes;
2573	info->bytes += bytes;
2574
2575	/* See try_merge_free_space() comment. */
2576	if (!btrfs_free_space_trimmed(info: bitmap))
2577	info->trim_state = BTRFS_TRIM_STATE_UNTRIMMED;
2578
2579	bitmap_clear_bits(ctl, info: bitmap, offset: info->offset, bytes, update_stat);
2580
2581	if (!bitmap->bytes)
2582	free_bitmap(ctl, bitmap_info: bitmap);
2583
2584	return true;
2585	}
2586
2587	/*
2588	* We prefer always to allocate from extent entries, both for clustered and
2589	* non-clustered allocation requests. So when attempting to add a new extent
2590	* entry, try to see if there's adjacent free space in bitmap entries, and if
2591	* there is, migrate that space from the bitmaps to the extent.
2592	* Like this we get better chances of satisfying space allocation requests
2593	* because we attempt to satisfy them based on a single cache entry, and never
2594	* on 2 or more entries - even if the entries represent a contiguous free space
2595	* region (e.g. 1 extent entry + 1 bitmap entry starting where the extent entry
2596	* ends).
2597	*/
2598	static void steal_from_bitmap(struct btrfs_free_space_ctl *ctl,
2599	struct btrfs_free_space *info,
2600	bool update_stat)
2601	{
2602	/*
2603	* Only work with disconnected entries, as we can change their offset,
2604	* and must be extent entries.
2605	*/
2606	ASSERT(!info->bitmap);
2607	ASSERT(RB_EMPTY_NODE(&info->offset_index));
2608
2609	if (ctl->total_bitmaps > 0) {
2610	bool stole_end;
2611	bool stole_front = false;
2612
2613	stole_end = steal_from_bitmap_to_end(ctl, info, update_stat);
2614	if (ctl->total_bitmaps > 0)
2615	stole_front = steal_from_bitmap_to_front(ctl, info,
2616	update_stat);
2617
2618	if (stole_end || stole_front)
2619	try_merge_free_space(ctl, info, update_stat);
2620	}
2621	}
2622
2623	static int __btrfs_add_free_space(struct btrfs_block_group *block_group,
2624	u64 offset, u64 bytes,
2625	enum btrfs_trim_state trim_state)
2626	{
2627	struct btrfs_fs_info *fs_info = block_group->fs_info;
2628	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2629	struct btrfs_free_space *info;
2630	int ret = 0;
2631	u64 filter_bytes = bytes;
2632
2633	ASSERT(!btrfs_is_zoned(fs_info));
2634
2635	info = kmem_cache_zalloc(btrfs_free_space_cachep, GFP_NOFS);
2636	if (!info)
2637	return -ENOMEM;
2638
2639	info->offset = offset;
2640	info->bytes = bytes;
2641	info->trim_state = trim_state;
2642	RB_CLEAR_NODE(&info->offset_index);
2643	RB_CLEAR_NODE(&info->bytes_index);
2644
2645	spin_lock(lock: &ctl->tree_lock);
2646
2647	if (try_merge_free_space(ctl, info, update_stat: true))
2648	goto link;
2649
2650	/*
2651	* There was no extent directly to the left or right of this new
2652	* extent then we know we're going to have to allocate a new extent, so
2653	* before we do that see if we need to drop this into a bitmap
2654	*/
2655	ret = insert_into_bitmap(ctl, info);
2656	if (ret < 0) {
2657	goto out;
2658	} else if (ret) {
2659	ret = 0;
2660	goto out;
2661	}
2662	link:
2663	/*
2664	* Only steal free space from adjacent bitmaps if we're sure we're not
2665	* going to add the new free space to existing bitmap entries - because
2666	* that would mean unnecessary work that would be reverted. Therefore
2667	* attempt to steal space from bitmaps if we're adding an extent entry.
2668	*/
2669	steal_from_bitmap(ctl, info, update_stat: true);
2670
2671	filter_bytes = max(filter_bytes, info->bytes);
2672
2673	ret = link_free_space(ctl, info);
2674	if (ret)
2675	kmem_cache_free(s: btrfs_free_space_cachep, objp: info);
2676	out:
2677	btrfs_discard_update_discardable(block_group);
2678	spin_unlock(lock: &ctl->tree_lock);
2679
2680	if (ret) {
2681	btrfs_crit(fs_info, "unable to add free space :%d", ret);
2682	ASSERT(ret != -EEXIST);
2683	}
2684
2685	if (trim_state != BTRFS_TRIM_STATE_TRIMMED) {
2686	btrfs_discard_check_filter(block_group, bytes: filter_bytes);
2687	btrfs_discard_queue_work(discard_ctl: &fs_info->discard_ctl, block_group);
2688	}
2689
2690	return ret;
2691	}
2692
2693	static int __btrfs_add_free_space_zoned(struct btrfs_block_group *block_group,
2694	u64 bytenr, u64 size, bool used)
2695	{
2696	struct btrfs_space_info *sinfo = block_group->space_info;
2697	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2698	u64 offset = bytenr - block_group->start;
2699	u64 to_free, to_unusable;
2700	int bg_reclaim_threshold = 0;
2701	bool initial;
2702	u64 reclaimable_unusable;
2703
2704	spin_lock(lock: &block_group->lock);
2705
2706	initial = ((size == block_group->length) && (block_group->alloc_offset == 0));
2707	WARN_ON(!initial && offset + size > block_group->zone_capacity);
2708	if (!initial)
2709	bg_reclaim_threshold = READ_ONCE(sinfo->bg_reclaim_threshold);
2710
2711	if (!used)
2712	to_free = size;
2713	else if (initial)
2714	to_free = block_group->zone_capacity;
2715	else if (offset >= block_group->alloc_offset)
2716	to_free = size;
2717	else if (offset + size <= block_group->alloc_offset)
2718	to_free = 0;
2719	else
2720	to_free = offset + size - block_group->alloc_offset;
2721	to_unusable = size - to_free;
2722
2723	spin_lock(lock: &ctl->tree_lock);
2724	ctl->free_space += to_free;
2725	spin_unlock(lock: &ctl->tree_lock);
2726	/*
2727	* If the block group is read-only, we should account freed space into
2728	* bytes_readonly.
2729	*/
2730	if (!block_group->ro) {
2731	block_group->zone_unusable += to_unusable;
2732	WARN_ON(block_group->zone_unusable > block_group->length);
2733	}
2734	if (!used) {
2735	block_group->alloc_offset -= size;
2736	}
2737
2738	reclaimable_unusable = block_group->zone_unusable -
2739	(block_group->length - block_group->zone_capacity);
2740	/* All the region is now unusable. Mark it as unused and reclaim */
2741	if (block_group->zone_unusable == block_group->length) {
2742	btrfs_mark_bg_unused(bg: block_group);
2743	} else if (bg_reclaim_threshold &&
2744	reclaimable_unusable >=
2745	mult_perc(num: block_group->zone_capacity, percent: bg_reclaim_threshold)) {
2746	btrfs_mark_bg_to_reclaim(bg: block_group);
2747	}
2748
2749	spin_unlock(lock: &block_group->lock);
2750
2751	return 0;
2752	}
2753
2754	int btrfs_add_free_space(struct btrfs_block_group *block_group,
2755	u64 bytenr, u64 size)
2756	{
2757	enum btrfs_trim_state trim_state = BTRFS_TRIM_STATE_UNTRIMMED;
2758
2759	if (btrfs_is_zoned(fs_info: block_group->fs_info))
2760	return __btrfs_add_free_space_zoned(block_group, bytenr, size,
2761	used: true);
2762
2763	if (btrfs_test_opt(block_group->fs_info, DISCARD_SYNC))
2764	trim_state = BTRFS_TRIM_STATE_TRIMMED;
2765
2766	return __btrfs_add_free_space(block_group, offset: bytenr, bytes: size, trim_state);
2767	}
2768
2769	int btrfs_add_free_space_unused(struct btrfs_block_group *block_group,
2770	u64 bytenr, u64 size)
2771	{
2772	if (btrfs_is_zoned(fs_info: block_group->fs_info))
2773	return __btrfs_add_free_space_zoned(block_group, bytenr, size,
2774	used: false);
2775
2776	return btrfs_add_free_space(block_group, bytenr, size);
2777	}
2778
2779	/*
2780	* This is a subtle distinction because when adding free space back in general,
2781	* we want it to be added as untrimmed for async. But in the case where we add
2782	* it on loading of a block group, we want to consider it trimmed.
2783	*/
2784	int btrfs_add_free_space_async_trimmed(struct btrfs_block_group *block_group,
2785	u64 bytenr, u64 size)
2786	{
2787	enum btrfs_trim_state trim_state = BTRFS_TRIM_STATE_UNTRIMMED;
2788
2789	if (btrfs_is_zoned(fs_info: block_group->fs_info))
2790	return __btrfs_add_free_space_zoned(block_group, bytenr, size,
2791	used: true);
2792
2793	if (btrfs_test_opt(block_group->fs_info, DISCARD_SYNC) ||
2794	btrfs_test_opt(block_group->fs_info, DISCARD_ASYNC))
2795	trim_state = BTRFS_TRIM_STATE_TRIMMED;
2796
2797	return __btrfs_add_free_space(block_group, offset: bytenr, bytes: size, trim_state);
2798	}
2799
2800	int btrfs_remove_free_space(struct btrfs_block_group *block_group,
2801	u64 offset, u64 bytes)
2802	{
2803	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2804	struct btrfs_free_space *info;
2805	int ret;
2806	bool re_search = false;
2807
2808	if (btrfs_is_zoned(fs_info: block_group->fs_info)) {
2809	/*
2810	* This can happen with conventional zones when replaying log.
2811	* Since the allocation info of tree-log nodes are not recorded
2812	* to the extent-tree, calculate_alloc_pointer() failed to
2813	* advance the allocation pointer after last allocated tree log
2814	* node blocks.
2815	*
2816	* This function is called from
2817	* btrfs_pin_extent_for_log_replay() when replaying the log.
2818	* Advance the pointer not to overwrite the tree-log nodes.
2819	*/
2820	if (block_group->start + block_group->alloc_offset <
2821	offset + bytes) {
2822	block_group->alloc_offset =
2823	offset + bytes - block_group->start;
2824	}
2825	return 0;
2826	}
2827
2828	spin_lock(lock: &ctl->tree_lock);
2829
2830	again:
2831	ret = 0;
2832	if (!bytes)
2833	goto out_lock;
2834
2835	info = tree_search_offset(ctl, offset, bitmap_only: 0, fuzzy: 0);
2836	if (!info) {
2837	/*
2838	* oops didn't find an extent that matched the space we wanted
2839	* to remove, look for a bitmap instead
2840	*/
2841	info = tree_search_offset(ctl, offset: offset_to_bitmap(ctl, offset),
2842	bitmap_only: 1, fuzzy: 0);
2843	if (!info) {
2844	/*
2845	* If we found a partial bit of our free space in a
2846	* bitmap but then couldn't find the other part this may
2847	* be a problem, so WARN about it.
2848	*/
2849	WARN_ON(re_search);
2850	goto out_lock;
2851	}
2852	}
2853
2854	re_search = false;
2855	if (!info->bitmap) {
2856	unlink_free_space(ctl, info, update_stat: true);
2857	if (offset == info->offset) {
2858	u64 to_free = min(bytes, info->bytes);
2859
2860	info->bytes -= to_free;
2861	info->offset += to_free;
2862	if (info->bytes) {
2863	ret = link_free_space(ctl, info);
2864	WARN_ON(ret);
2865	} else {
2866	kmem_cache_free(s: btrfs_free_space_cachep, objp: info);
2867	}
2868
2869	offset += to_free;
2870	bytes -= to_free;
2871	goto again;
2872	} else {
2873	u64 old_end = info->bytes + info->offset;
2874
2875	info->bytes = offset - info->offset;
2876	ret = link_free_space(ctl, info);
2877	WARN_ON(ret);
2878	if (ret)
2879	goto out_lock;
2880
2881	/* Not enough bytes in this entry to satisfy us */
2882	if (old_end < offset + bytes) {
2883	bytes -= old_end - offset;
2884	offset = old_end;
2885	goto again;
2886	} else if (old_end == offset + bytes) {
2887	/* all done */
2888	goto out_lock;
2889	}
2890	spin_unlock(lock: &ctl->tree_lock);
2891
2892	ret = __btrfs_add_free_space(block_group,
2893	offset: offset + bytes,
2894	bytes: old_end - (offset + bytes),
2895	trim_state: info->trim_state);
2896	WARN_ON(ret);
2897	goto out;
2898	}
2899	}
2900
2901	ret = remove_from_bitmap(ctl, bitmap_info: info, offset: &offset, bytes: &bytes);
2902	if (ret == -EAGAIN) {
2903	re_search = true;
2904	goto again;
2905	}
2906	out_lock:
2907	btrfs_discard_update_discardable(block_group);
2908	spin_unlock(lock: &ctl->tree_lock);
2909	out:
2910	return ret;
2911	}
2912
2913	void btrfs_dump_free_space(struct btrfs_block_group *block_group,
2914	u64 bytes)
2915	{
2916	struct btrfs_fs_info *fs_info = block_group->fs_info;
2917	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2918	struct btrfs_free_space *info;
2919	struct rb_node *n;
2920	int count = 0;
2921
2922	/*
2923	* Zoned btrfs does not use free space tree and cluster. Just print
2924	* out the free space after the allocation offset.
2925	*/
2926	if (btrfs_is_zoned(fs_info)) {
2927	btrfs_info(fs_info, "free space %llu active %d",
2928	block_group->zone_capacity - block_group->alloc_offset,
2929	test_bit(BLOCK_GROUP_FLAG_ZONE_IS_ACTIVE,
2930	&block_group->runtime_flags));
2931	return;
2932	}
2933
2934	spin_lock(lock: &ctl->tree_lock);
2935	for (n = rb_first(root: &ctl->free_space_offset); n; n = rb_next(n)) {
2936	info = rb_entry(n, struct btrfs_free_space, offset_index);
2937	if (info->bytes >= bytes && !block_group->ro)
2938	count++;
2939	btrfs_crit(fs_info, "entry offset %llu, bytes %llu, bitmap %s",
2940	info->offset, info->bytes, str_yes_no(info->bitmap));
2941	}
2942	spin_unlock(lock: &ctl->tree_lock);
2943	btrfs_info(fs_info, "block group has cluster?: %s",
2944	str_no_yes(list_empty(&block_group->cluster_list)));
2945	btrfs_info(fs_info,
2946	"%d free space entries at or bigger than %llu bytes",
2947	count, bytes);
2948	}
2949
2950	void btrfs_init_free_space_ctl(struct btrfs_block_group *block_group,
2951	struct btrfs_free_space_ctl *ctl)
2952	{
2953	struct btrfs_fs_info *fs_info = block_group->fs_info;
2954
2955	spin_lock_init(&ctl->tree_lock);
2956	ctl->unit = fs_info->sectorsize;
2957	ctl->start = block_group->start;
2958	ctl->block_group = block_group;
2959	ctl->op = &free_space_op;
2960	ctl->free_space_bytes = RB_ROOT_CACHED;
2961	INIT_LIST_HEAD(list: &ctl->trimming_ranges);
2962	mutex_init(&ctl->cache_writeout_mutex);
2963
2964	/*
2965	* we only want to have 32k of ram per block group for keeping
2966	* track of free space, and if we pass 1/2 of that we want to
2967	* start converting things over to using bitmaps
2968	*/
2969	ctl->extents_thresh = (SZ_32K / 2) / sizeof(struct btrfs_free_space);
2970	}
2971
2972	/*
2973	* for a given cluster, put all of its extents back into the free
2974	* space cache. If the block group passed doesn't match the block group
2975	* pointed to by the cluster, someone else raced in and freed the
2976	* cluster already. In that case, we just return without changing anything
2977	*/
2978	static void __btrfs_return_cluster_to_free_space(
2979	struct btrfs_block_group *block_group,
2980	struct btrfs_free_cluster *cluster)
2981	{
2982	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2983	struct rb_node *node;
2984
2985	lockdep_assert_held(&ctl->tree_lock);
2986
2987	spin_lock(lock: &cluster->lock);
2988	if (cluster->block_group != block_group) {
2989	spin_unlock(lock: &cluster->lock);
2990	return;
2991	}
2992
2993	cluster->block_group = NULL;
2994	cluster->window_start = 0;
2995	list_del_init(entry: &cluster->block_group_list);
2996
2997	node = rb_first(root: &cluster->root);
2998	while (node) {
2999	struct btrfs_free_space *entry;
3000
3001	entry = rb_entry(node, struct btrfs_free_space, offset_index);
3002	node = rb_next(&entry->offset_index);
3003	rb_erase(&entry->offset_index, &cluster->root);
3004	RB_CLEAR_NODE(&entry->offset_index);
3005
3006	if (!entry->bitmap) {
3007	/* Merging treats extents as if they were new */
3008	if (!btrfs_free_space_trimmed(info: entry)) {
3009	ctl->discardable_extents[BTRFS_STAT_CURR]--;
3010	ctl->discardable_bytes[BTRFS_STAT_CURR] -=
3011	entry->bytes;
3012	}
3013
3014	try_merge_free_space(ctl, info: entry, update_stat: false);
3015	steal_from_bitmap(ctl, info: entry, update_stat: false);
3016
3017	/* As we insert directly, update these statistics */
3018	if (!btrfs_free_space_trimmed(info: entry)) {
3019	ctl->discardable_extents[BTRFS_STAT_CURR]++;
3020	ctl->discardable_bytes[BTRFS_STAT_CURR] +=
3021	entry->bytes;
3022	}
3023	}
3024	tree_insert_offset(ctl, NULL, new_entry: entry);
3025	rb_add_cached(node: &entry->bytes_index, tree: &ctl->free_space_bytes,
3026	less: entry_less);
3027	}
3028	cluster->root = RB_ROOT;
3029	spin_unlock(lock: &cluster->lock);
3030	btrfs_put_block_group(cache: block_group);
3031	}
3032
3033	void btrfs_remove_free_space_cache(struct btrfs_block_group *block_group)
3034	{
3035	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
3036	struct btrfs_free_cluster *cluster;
3037	struct list_head *head;
3038
3039	spin_lock(lock: &ctl->tree_lock);
3040	while ((head = block_group->cluster_list.next) !=
3041	&block_group->cluster_list) {
3042	cluster = list_entry(head, struct btrfs_free_cluster,
3043	block_group_list);
3044
3045	WARN_ON(cluster->block_group != block_group);
3046	__btrfs_return_cluster_to_free_space(block_group, cluster);
3047
3048	cond_resched_lock(&ctl->tree_lock);
3049	}
3050	__btrfs_remove_free_space_cache(ctl);
3051	btrfs_discard_update_discardable(block_group);
3052	spin_unlock(lock: &ctl->tree_lock);
3053
3054	}
3055
3056	/*
3057	* Walk @block_group's free space rb_tree to determine if everything is trimmed.
3058	*/
3059	bool btrfs_is_free_space_trimmed(struct btrfs_block_group *block_group)
3060	{
3061	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
3062	struct btrfs_free_space *info;
3063	struct rb_node *node;
3064	bool ret = true;
3065
3066	spin_lock(lock: &ctl->tree_lock);
3067	node = rb_first(root: &ctl->free_space_offset);
3068
3069	while (node) {
3070	info = rb_entry(node, struct btrfs_free_space, offset_index);
3071
3072	if (!btrfs_free_space_trimmed(info)) {
3073	ret = false;
3074	break;
3075	}
3076
3077	node = rb_next(node);
3078	}
3079
3080	spin_unlock(lock: &ctl->tree_lock);
3081	return ret;
3082	}
3083
3084	u64 btrfs_find_space_for_alloc(struct btrfs_block_group *block_group,
3085	u64 offset, u64 bytes, u64 empty_size,
3086	u64 *max_extent_size)
3087	{
3088	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
3089	struct btrfs_discard_ctl *discard_ctl =
3090	&block_group->fs_info->discard_ctl;
3091	struct btrfs_free_space *entry = NULL;
3092	u64 bytes_search = bytes + empty_size;
3093	u64 ret = 0;
3094	u64 align_gap = 0;
3095	u64 align_gap_len = 0;
3096	enum btrfs_trim_state align_gap_trim_state = BTRFS_TRIM_STATE_UNTRIMMED;
3097	bool use_bytes_index = (offset == block_group->start);
3098
3099	ASSERT(!btrfs_is_zoned(block_group->fs_info));
3100
3101	spin_lock(lock: &ctl->tree_lock);
3102	entry = find_free_space(ctl, offset: &offset, bytes: &bytes_search,
3103	align: block_group->full_stripe_len, max_extent_size,
3104	use_bytes_index);
3105	if (!entry)
3106	goto out;
3107
3108	ret = offset;
3109	if (entry->bitmap) {
3110	bitmap_clear_bits(ctl, info: entry, offset, bytes, update_stat: true);
3111
3112	if (!btrfs_free_space_trimmed(info: entry))
3113	atomic64_add(i: bytes, v: &discard_ctl->discard_bytes_saved);
3114
3115	if (!entry->bytes)
3116	free_bitmap(ctl, bitmap_info: entry);
3117	} else {
3118	unlink_free_space(ctl, info: entry, update_stat: true);
3119	align_gap_len = offset - entry->offset;
3120	align_gap = entry->offset;
3121	align_gap_trim_state = entry->trim_state;
3122
3123	if (!btrfs_free_space_trimmed(info: entry))
3124	atomic64_add(i: bytes, v: &discard_ctl->discard_bytes_saved);
3125
3126	entry->offset = offset + bytes;
3127	WARN_ON(entry->bytes < bytes + align_gap_len);
3128
3129	entry->bytes -= bytes + align_gap_len;
3130	if (!entry->bytes)
3131	kmem_cache_free(s: btrfs_free_space_cachep, objp: entry);
3132	else
3133	link_free_space(ctl, info: entry);
3134	}
3135	out:
3136	btrfs_discard_update_discardable(block_group);
3137	spin_unlock(lock: &ctl->tree_lock);
3138
3139	if (align_gap_len)
3140	__btrfs_add_free_space(block_group, offset: align_gap, bytes: align_gap_len,
3141	trim_state: align_gap_trim_state);
3142	return ret;
3143	}
3144
3145	/*
3146	* given a cluster, put all of its extents back into the free space
3147	* cache. If a block group is passed, this function will only free
3148	* a cluster that belongs to the passed block group.
3149	*
3150	* Otherwise, it'll get a reference on the block group pointed to by the
3151	* cluster and remove the cluster from it.
3152	*/
3153	void btrfs_return_cluster_to_free_space(
3154	struct btrfs_block_group *block_group,
3155	struct btrfs_free_cluster *cluster)
3156	{
3157	struct btrfs_free_space_ctl *ctl;
3158
3159	/* first, get a safe pointer to the block group */
3160	spin_lock(lock: &cluster->lock);
3161	if (!block_group) {
3162	block_group = cluster->block_group;
3163	if (!block_group) {
3164	spin_unlock(lock: &cluster->lock);
3165	return;
3166	}
3167	} else if (cluster->block_group != block_group) {
3168	/* someone else has already freed it don't redo their work */
3169	spin_unlock(lock: &cluster->lock);
3170	return;
3171	}
3172	btrfs_get_block_group(cache: block_group);
3173	spin_unlock(lock: &cluster->lock);
3174
3175	ctl = block_group->free_space_ctl;
3176
3177	/* now return any extents the cluster had on it */
3178	spin_lock(lock: &ctl->tree_lock);
3179	__btrfs_return_cluster_to_free_space(block_group, cluster);
3180	spin_unlock(lock: &ctl->tree_lock);
3181
3182	btrfs_discard_queue_work(discard_ctl: &block_group->fs_info->discard_ctl, block_group);
3183
3184	/* finally drop our ref */
3185	btrfs_put_block_group(cache: block_group);
3186	}
3187
3188	static u64 btrfs_alloc_from_bitmap(struct btrfs_block_group *block_group,
3189	struct btrfs_free_cluster *cluster,
3190	struct btrfs_free_space *entry,
3191	u64 bytes, u64 min_start,
3192	u64 *max_extent_size)
3193	{
3194	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
3195	int ret2;
3196	u64 search_start = cluster->window_start;
3197	u64 search_bytes = bytes;
3198	u64 ret = 0;
3199
3200	search_start = min_start;
3201	search_bytes = bytes;
3202
3203	ret2 = search_bitmap(ctl, bitmap_info: entry, offset: &search_start, bytes: &search_bytes, for_alloc: true);
3204	if (ret2) {
3205	*max_extent_size = max(get_max_extent_size(entry),
3206	*max_extent_size);
3207	return 0;
3208	}
3209
3210	ret = search_start;
3211	bitmap_clear_bits(ctl, info: entry, offset: ret, bytes, update_stat: false);
3212
3213	return ret;
3214	}
3215
3216	/*
3217	* given a cluster, try to allocate 'bytes' from it, returns 0
3218	* if it couldn't find anything suitably large, or a logical disk offset
3219	* if things worked out
3220	*/
3221	u64 btrfs_alloc_from_cluster(struct btrfs_block_group *block_group,
3222	struct btrfs_free_cluster *cluster, u64 bytes,
3223	u64 min_start, u64 *max_extent_size)
3224	{
3225	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
3226	struct btrfs_discard_ctl *discard_ctl =
3227	&block_group->fs_info->discard_ctl;
3228	struct btrfs_free_space *entry = NULL;
3229	struct rb_node *node;
3230	u64 ret = 0;
3231
3232	ASSERT(!btrfs_is_zoned(block_group->fs_info));
3233
3234	spin_lock(lock: &cluster->lock);
3235	if (bytes > cluster->max_size)
3236	goto out;
3237
3238	if (cluster->block_group != block_group)
3239	goto out;
3240
3241	node = rb_first(root: &cluster->root);
3242	if (!node)
3243	goto out;
3244
3245	entry = rb_entry(node, struct btrfs_free_space, offset_index);
3246	while (1) {
3247	if (entry->bytes < bytes)
3248	*max_extent_size = max(get_max_extent_size(entry),
3249	*max_extent_size);
3250
3251	if (entry->bytes < bytes ||
3252	(!entry->bitmap && entry->offset < min_start)) {
3253	node = rb_next(&entry->offset_index);
3254	if (!node)
3255	break;
3256	entry = rb_entry(node, struct btrfs_free_space,
3257	offset_index);
3258	continue;
3259	}
3260
3261	if (entry->bitmap) {
3262	ret = btrfs_alloc_from_bitmap(block_group,
3263	cluster, entry, bytes,
3264	min_start: cluster->window_start,
3265	max_extent_size);
3266	if (ret == 0) {
3267	node = rb_next(&entry->offset_index);
3268	if (!node)
3269	break;
3270	entry = rb_entry(node, struct btrfs_free_space,
3271	offset_index);
3272	continue;
3273	}
3274	cluster->window_start += bytes;
3275	} else {
3276	ret = entry->offset;
3277
3278	entry->offset += bytes;
3279	entry->bytes -= bytes;
3280	}
3281
3282	break;
3283	}
3284	out:
3285	spin_unlock(lock: &cluster->lock);
3286
3287	if (!ret)
3288	return 0;
3289
3290	spin_lock(lock: &ctl->tree_lock);
3291
3292	if (!btrfs_free_space_trimmed(info: entry))
3293	atomic64_add(i: bytes, v: &discard_ctl->discard_bytes_saved);
3294
3295	ctl->free_space -= bytes;
3296	if (!entry->bitmap && !btrfs_free_space_trimmed(info: entry))
3297	ctl->discardable_bytes[BTRFS_STAT_CURR] -= bytes;
3298
3299	spin_lock(lock: &cluster->lock);
3300	if (entry->bytes == 0) {
3301	rb_erase(&entry->offset_index, &cluster->root);
3302	ctl->free_extents--;
3303	if (entry->bitmap) {
3304	kmem_cache_free(s: btrfs_free_space_bitmap_cachep,
3305	objp: entry->bitmap);
3306	ctl->total_bitmaps--;
3307	recalculate_thresholds(ctl);
3308	} else if (!btrfs_free_space_trimmed(info: entry)) {
3309	ctl->discardable_extents[BTRFS_STAT_CURR]--;
3310	}
3311	kmem_cache_free(s: btrfs_free_space_cachep, objp: entry);
3312	}
3313
3314	spin_unlock(lock: &cluster->lock);
3315	spin_unlock(lock: &ctl->tree_lock);
3316
3317	return ret;
3318	}
3319
3320	static int btrfs_bitmap_cluster(struct btrfs_block_group *block_group,
3321	struct btrfs_free_space *entry,
3322	struct btrfs_free_cluster *cluster,
3323	u64 offset, u64 bytes,
3324	u64 cont1_bytes, u64 min_bytes)
3325	{
3326	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
3327	unsigned long next_zero;
3328	unsigned long i;
3329	unsigned long want_bits;
3330	unsigned long min_bits;
3331	unsigned long found_bits;
3332	unsigned long max_bits = 0;
3333	unsigned long start = 0;
3334	unsigned long total_found = 0;
3335	int ret;
3336
3337	lockdep_assert_held(&ctl->tree_lock);
3338
3339	i = offset_to_bit(bitmap_start: entry->offset, unit: ctl->unit,
3340	max_t(u64, offset, entry->offset));
3341	want_bits = bytes_to_bits(bytes, unit: ctl->unit);
3342	min_bits = bytes_to_bits(bytes: min_bytes, unit: ctl->unit);
3343
3344	/*
3345	* Don't bother looking for a cluster in this bitmap if it's heavily
3346	* fragmented.
3347	*/
3348	if (entry->max_extent_size &&
3349	entry->max_extent_size < cont1_bytes)
3350	return -ENOSPC;
3351	again:
3352	found_bits = 0;
3353	for_each_set_bit_from(i, entry->bitmap, BITS_PER_BITMAP) {
3354	next_zero = find_next_zero_bit(addr: entry->bitmap,
3355	BITS_PER_BITMAP, offset: i);
3356	if (next_zero - i >= min_bits) {
3357	found_bits = next_zero - i;
3358	if (found_bits > max_bits)
3359	max_bits = found_bits;
3360	break;
3361	}
3362	if (next_zero - i > max_bits)
3363	max_bits = next_zero - i;
3364	i = next_zero;
3365	}
3366
3367	if (!found_bits) {
3368	entry->max_extent_size = (u64)max_bits * ctl->unit;
3369	return -ENOSPC;
3370	}
3371
3372	if (!total_found) {
3373	start = i;
3374	cluster->max_size = 0;
3375	}
3376
3377	total_found += found_bits;
3378
3379	if (cluster->max_size < found_bits * ctl->unit)
3380	cluster->max_size = found_bits * ctl->unit;
3381
3382	if (total_found < want_bits || cluster->max_size < cont1_bytes) {
3383	i = next_zero + 1;
3384	goto again;
3385	}
3386
3387	cluster->window_start = start * ctl->unit + entry->offset;
3388	rb_erase(&entry->offset_index, &ctl->free_space_offset);
3389	rb_erase_cached(node: &entry->bytes_index, root: &ctl->free_space_bytes);
3390
3391	/*
3392	* We need to know if we're currently on the normal space index when we
3393	* manipulate the bitmap so that we know we need to remove and re-insert
3394	* it into the space_index tree. Clear the bytes_index node here so the
3395	* bitmap manipulation helpers know not to mess with the space_index
3396	* until this bitmap entry is added back into the normal cache.
3397	*/
3398	RB_CLEAR_NODE(&entry->bytes_index);
3399
3400	ret = tree_insert_offset(ctl, cluster, new_entry: entry);
3401	ASSERT(!ret); /* -EEXIST; Logic error */
3402
3403	trace_btrfs_setup_cluster(block_group, cluster,
3404	size: total_found * ctl->unit, bitmap: 1);
3405	return 0;
3406	}
3407
3408	/*
3409	* This searches the block group for just extents to fill the cluster with.
3410	* Try to find a cluster with at least bytes total bytes, at least one
3411	* extent of cont1_bytes, and other clusters of at least min_bytes.
3412	*/
3413	static noinline int
3414	setup_cluster_no_bitmap(struct btrfs_block_group *block_group,
3415	struct btrfs_free_cluster *cluster,
3416	struct list_head *bitmaps, u64 offset, u64 bytes,
3417	u64 cont1_bytes, u64 min_bytes)
3418	{
3419	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
3420	struct btrfs_free_space *first = NULL;
3421	struct btrfs_free_space *entry = NULL;
3422	struct btrfs_free_space *last;
3423	struct rb_node *node;
3424	u64 window_free;
3425	u64 max_extent;
3426	u64 total_size = 0;
3427
3428	lockdep_assert_held(&ctl->tree_lock);
3429
3430	entry = tree_search_offset(ctl, offset, bitmap_only: 0, fuzzy: 1);
3431	if (!entry)
3432	return -ENOSPC;
3433
3434	/*
3435	* We don't want bitmaps, so just move along until we find a normal
3436	* extent entry.
3437	*/
3438	while (entry->bitmap || entry->bytes < min_bytes) {
3439	if (entry->bitmap && list_empty(head: &entry->list))
3440	list_add_tail(new: &entry->list, head: bitmaps);
3441	node = rb_next(&entry->offset_index);
3442	if (!node)
3443	return -ENOSPC;
3444	entry = rb_entry(node, struct btrfs_free_space, offset_index);
3445	}
3446
3447	window_free = entry->bytes;
3448	max_extent = entry->bytes;
3449	first = entry;
3450	last = entry;
3451
3452	for (node = rb_next(&entry->offset_index); node;
3453	node = rb_next(&entry->offset_index)) {
3454	entry = rb_entry(node, struct btrfs_free_space, offset_index);
3455
3456	if (entry->bitmap) {
3457	if (list_empty(head: &entry->list))
3458	list_add_tail(new: &entry->list, head: bitmaps);
3459	continue;
3460	}
3461
3462	if (entry->bytes < min_bytes)
3463	continue;
3464
3465	last = entry;
3466	window_free += entry->bytes;
3467	if (entry->bytes > max_extent)
3468	max_extent = entry->bytes;
3469	}
3470
3471	if (window_free < bytes || max_extent < cont1_bytes)
3472	return -ENOSPC;
3473
3474	cluster->window_start = first->offset;
3475
3476	node = &first->offset_index;
3477
3478	/*
3479	* now we've found our entries, pull them out of the free space
3480	* cache and put them into the cluster rbtree
3481	*/
3482	do {
3483	int ret;
3484
3485	entry = rb_entry(node, struct btrfs_free_space, offset_index);
3486	node = rb_next(&entry->offset_index);
3487	if (entry->bitmap || entry->bytes < min_bytes)
3488	continue;
3489
3490	rb_erase(&entry->offset_index, &ctl->free_space_offset);
3491	rb_erase_cached(node: &entry->bytes_index, root: &ctl->free_space_bytes);
3492	ret = tree_insert_offset(ctl, cluster, new_entry: entry);
3493	total_size += entry->bytes;
3494	ASSERT(!ret); /* -EEXIST; Logic error */
3495	} while (node && entry != last);
3496
3497	cluster->max_size = max_extent;
3498	trace_btrfs_setup_cluster(block_group, cluster, size: total_size, bitmap: 0);
3499	return 0;
3500	}
3501
3502	/*
3503	* This specifically looks for bitmaps that may work in the cluster, we assume
3504	* that we have already failed to find extents that will work.
3505	*/
3506	static noinline int
3507	setup_cluster_bitmap(struct btrfs_block_group *block_group,
3508	struct btrfs_free_cluster *cluster,
3509	struct list_head *bitmaps, u64 offset, u64 bytes,
3510	u64 cont1_bytes, u64 min_bytes)
3511	{
3512	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
3513	struct btrfs_free_space *entry = NULL;
3514	int ret = -ENOSPC;
3515	u64 bitmap_offset = offset_to_bitmap(ctl, offset);
3516
3517	if (ctl->total_bitmaps == 0)
3518	return -ENOSPC;
3519
3520	/*
3521	* The bitmap that covers offset won't be in the list unless offset
3522	* is just its start offset.
3523	*/
3524	if (!list_empty(head: bitmaps))
3525	entry = list_first_entry(bitmaps, struct btrfs_free_space, list);
3526
3527	if (!entry || entry->offset != bitmap_offset) {
3528	entry = tree_search_offset(ctl, offset: bitmap_offset, bitmap_only: 1, fuzzy: 0);
3529	if (entry && list_empty(head: &entry->list))
3530	list_add(new: &entry->list, head: bitmaps);
3531	}
3532
3533	list_for_each_entry(entry, bitmaps, list) {
3534	if (entry->bytes < bytes)
3535	continue;
3536	ret = btrfs_bitmap_cluster(block_group, entry, cluster, offset,
3537	bytes, cont1_bytes, min_bytes);
3538	if (!ret)
3539	return 0;
3540	}
3541
3542	/*
3543	* The bitmaps list has all the bitmaps that record free space
3544	* starting after offset, so no more search is required.
3545	*/
3546	return -ENOSPC;
3547	}
3548
3549	/*
3550	* here we try to find a cluster of blocks in a block group. The goal
3551	* is to find at least bytes+empty_size.
3552	* We might not find them all in one contiguous area.
3553	*
3554	* returns zero and sets up cluster if things worked out, otherwise
3555	* it returns -enospc
3556	*/
3557	int btrfs_find_space_cluster(struct btrfs_block_group *block_group,
3558	struct btrfs_free_cluster *cluster,
3559	u64 offset, u64 bytes, u64 empty_size)
3560	{
3561	struct btrfs_fs_info *fs_info = block_group->fs_info;
3562	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
3563	struct btrfs_free_space *entry, *tmp;
3564	LIST_HEAD(bitmaps);
3565	u64 min_bytes;
3566	u64 cont1_bytes;
3567	int ret;
3568
3569	/*
3570	* Choose the minimum extent size we'll require for this
3571	* cluster. For SSD_SPREAD, don't allow any fragmentation.
3572	* For metadata, allow allocates with smaller extents. For
3573	* data, keep it dense.
3574	*/
3575	if (btrfs_test_opt(fs_info, SSD_SPREAD)) {
3576	cont1_bytes = bytes + empty_size;
3577	min_bytes = cont1_bytes;
3578	} else if (block_group->flags & BTRFS_BLOCK_GROUP_METADATA) {
3579	cont1_bytes = bytes;
3580	min_bytes = fs_info->sectorsize;
3581	} else {
3582	cont1_bytes = max(bytes, (bytes + empty_size) >> 2);
3583	min_bytes = fs_info->sectorsize;
3584	}
3585
3586	spin_lock(lock: &ctl->tree_lock);
3587
3588	/*
3589	* If we know we don't have enough space to make a cluster don't even
3590	* bother doing all the work to try and find one.
3591	*/
3592	if (ctl->free_space < bytes) {
3593	spin_unlock(lock: &ctl->tree_lock);
3594	return -ENOSPC;
3595	}
3596
3597	spin_lock(lock: &cluster->lock);
3598
3599	/* someone already found a cluster, hooray */
3600	if (cluster->block_group) {
3601	ret = 0;
3602	goto out;
3603	}
3604
3605	trace_btrfs_find_cluster(block_group, start: offset, bytes, empty_size,
3606	min_bytes);
3607
3608	ret = setup_cluster_no_bitmap(block_group, cluster, bitmaps: &bitmaps, offset,
3609	bytes: bytes + empty_size,
3610	cont1_bytes, min_bytes);
3611	if (ret)
3612	ret = setup_cluster_bitmap(block_group, cluster, bitmaps: &bitmaps,
3613	offset, bytes: bytes + empty_size,
3614	cont1_bytes, min_bytes);
3615
3616	/* Clear our temporary list */
3617	list_for_each_entry_safe(entry, tmp, &bitmaps, list)
3618	list_del_init(entry: &entry->list);
3619
3620	if (!ret) {
3621	btrfs_get_block_group(cache: block_group);
3622	list_add_tail(new: &cluster->block_group_list,
3623	head: &block_group->cluster_list);
3624	cluster->block_group = block_group;
3625	} else {
3626	trace_btrfs_failed_cluster_setup(block_group);
3627	}
3628	out:
3629	spin_unlock(lock: &cluster->lock);
3630	spin_unlock(lock: &ctl->tree_lock);
3631
3632	return ret;
3633	}
3634
3635	/*
3636	* simple code to zero out a cluster
3637	*/
3638	void btrfs_init_free_cluster(struct btrfs_free_cluster *cluster)
3639	{
3640	spin_lock_init(&cluster->lock);
3641	spin_lock_init(&cluster->refill_lock);
3642	cluster->root = RB_ROOT;
3643	cluster->max_size = 0;
3644	cluster->fragmented = false;
3645	INIT_LIST_HEAD(list: &cluster->block_group_list);
3646	cluster->block_group = NULL;
3647	}
3648
3649	static int do_trimming(struct btrfs_block_group *block_group,
3650	u64 *total_trimmed, u64 start, u64 bytes,
3651	u64 reserved_start, u64 reserved_bytes,
3652	enum btrfs_trim_state reserved_trim_state,
3653	struct btrfs_trim_range *trim_entry)
3654	{
3655	struct btrfs_space_info *space_info = block_group->space_info;
3656	struct btrfs_fs_info *fs_info = block_group->fs_info;
3657	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
3658	int ret;
3659	bool bg_ro;
3660	const u64 end = start + bytes;
3661	const u64 reserved_end = reserved_start + reserved_bytes;
3662	enum btrfs_trim_state trim_state = BTRFS_TRIM_STATE_UNTRIMMED;
3663	u64 trimmed = 0;
3664
3665	spin_lock(lock: &space_info->lock);
3666	spin_lock(lock: &block_group->lock);
3667	bg_ro = block_group->ro;
3668	if (!bg_ro) {
3669	block_group->reserved += reserved_bytes;
3670	spin_unlock(lock: &block_group->lock);
3671	space_info->bytes_reserved += reserved_bytes;
3672	} else {
3673	spin_unlock(lock: &block_group->lock);
3674	}
3675	spin_unlock(lock: &space_info->lock);
3676
3677	ret = btrfs_discard_extent(fs_info, bytenr: start, num_bytes: bytes, actual_bytes: &trimmed);
3678	if (!ret) {
3679	*total_trimmed += trimmed;
3680	trim_state = BTRFS_TRIM_STATE_TRIMMED;
3681	}
3682
3683	mutex_lock(&ctl->cache_writeout_mutex);
3684	if (reserved_start < start)
3685	__btrfs_add_free_space(block_group, offset: reserved_start,
3686	bytes: start - reserved_start,
3687	trim_state: reserved_trim_state);
3688	if (end < reserved_end)
3689	__btrfs_add_free_space(block_group, offset: end, bytes: reserved_end - end,
3690	trim_state: reserved_trim_state);
3691	__btrfs_add_free_space(block_group, offset: start, bytes, trim_state);
3692	list_del(entry: &trim_entry->list);
3693	mutex_unlock(lock: &ctl->cache_writeout_mutex);
3694
3695	if (!bg_ro) {
3696	spin_lock(lock: &space_info->lock);
3697	spin_lock(lock: &block_group->lock);
3698	bg_ro = block_group->ro;
3699	block_group->reserved -= reserved_bytes;
3700	spin_unlock(lock: &block_group->lock);
3701
3702	space_info->bytes_reserved -= reserved_bytes;
3703	if (bg_ro)
3704	space_info->bytes_readonly += reserved_bytes;
3705	spin_unlock(lock: &space_info->lock);
3706	}
3707
3708	return ret;
3709	}
3710
3711	/*
3712	* If @async is set, then we will trim 1 region and return.
3713	*/
3714	static int trim_no_bitmap(struct btrfs_block_group *block_group,
3715	u64 *total_trimmed, u64 start, u64 end, u64 minlen,
3716	bool async)
3717	{
3718	struct btrfs_discard_ctl *discard_ctl =
3719	&block_group->fs_info->discard_ctl;
3720	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
3721	struct btrfs_free_space *entry;
3722	struct rb_node *node;
3723	int ret = 0;
3724	u64 extent_start;
3725	u64 extent_bytes;
3726	enum btrfs_trim_state extent_trim_state;
3727	u64 bytes;
3728	const u64 max_discard_size = READ_ONCE(discard_ctl->max_discard_size);
3729
3730	while (start < end) {
3731	struct btrfs_trim_range trim_entry;
3732
3733	mutex_lock(&ctl->cache_writeout_mutex);
3734	spin_lock(lock: &ctl->tree_lock);
3735
3736	if (ctl->free_space < minlen)
3737	goto out_unlock;
3738
3739	entry = tree_search_offset(ctl, offset: start, bitmap_only: 0, fuzzy: 1);
3740	if (!entry)
3741	goto out_unlock;
3742
3743	/* Skip bitmaps and if async, already trimmed entries */
3744	while (entry->bitmap ||
3745	(async && btrfs_free_space_trimmed(info: entry))) {
3746	node = rb_next(&entry->offset_index);
3747	if (!node)
3748	goto out_unlock;
3749	entry = rb_entry(node, struct btrfs_free_space,
3750	offset_index);
3751	}
3752
3753	if (entry->offset >= end)
3754	goto out_unlock;
3755
3756	extent_start = entry->offset;
3757	extent_bytes = entry->bytes;
3758	extent_trim_state = entry->trim_state;
3759	if (async) {
3760	start = entry->offset;
3761	bytes = entry->bytes;
3762	if (bytes < minlen) {
3763	spin_unlock(lock: &ctl->tree_lock);
3764	mutex_unlock(lock: &ctl->cache_writeout_mutex);
3765	goto next;
3766	}
3767	unlink_free_space(ctl, info: entry, update_stat: true);
3768	/*
3769	* Let bytes = BTRFS_MAX_DISCARD_SIZE + X.
3770	* If X < BTRFS_ASYNC_DISCARD_MIN_FILTER, we won't trim
3771	* X when we come back around. So trim it now.
3772	*/
3773	if (max_discard_size &&
3774	bytes >= (max_discard_size +
3775	BTRFS_ASYNC_DISCARD_MIN_FILTER)) {
3776	bytes = max_discard_size;
3777	extent_bytes = max_discard_size;
3778	entry->offset += max_discard_size;
3779	entry->bytes -= max_discard_size;
3780	link_free_space(ctl, info: entry);
3781	} else {
3782	kmem_cache_free(s: btrfs_free_space_cachep, objp: entry);
3783	}
3784	} else {
3785	start = max(start, extent_start);
3786	bytes = min(extent_start + extent_bytes, end) - start;
3787	if (bytes < minlen) {
3788	spin_unlock(lock: &ctl->tree_lock);
3789	mutex_unlock(lock: &ctl->cache_writeout_mutex);
3790	goto next;
3791	}
3792
3793	unlink_free_space(ctl, info: entry, update_stat: true);
3794	kmem_cache_free(s: btrfs_free_space_cachep, objp: entry);
3795	}
3796
3797	spin_unlock(lock: &ctl->tree_lock);
3798	trim_entry.start = extent_start;
3799	trim_entry.bytes = extent_bytes;
3800	list_add_tail(new: &trim_entry.list, head: &ctl->trimming_ranges);
3801	mutex_unlock(lock: &ctl->cache_writeout_mutex);
3802
3803	ret = do_trimming(block_group, total_trimmed, start, bytes,
3804	reserved_start: extent_start, reserved_bytes: extent_bytes, reserved_trim_state: extent_trim_state,
3805	trim_entry: &trim_entry);
3806	if (ret) {
3807	block_group->discard_cursor = start + bytes;
3808	break;
3809	}
3810	next:
3811	start += bytes;
3812	block_group->discard_cursor = start;
3813	if (async && *total_trimmed)
3814	break;
3815
3816	if (btrfs_trim_interrupted()) {
3817	ret = -ERESTARTSYS;
3818	break;
3819	}
3820
3821	cond_resched();
3822	}
3823
3824	return ret;
3825
3826	out_unlock:
3827	block_group->discard_cursor = btrfs_block_group_end(block_group);
3828	spin_unlock(lock: &ctl->tree_lock);
3829	mutex_unlock(lock: &ctl->cache_writeout_mutex);
3830
3831	return ret;
3832	}
3833
3834	/*
3835	* If we break out of trimming a bitmap prematurely, we should reset the
3836	* trimming bit. In a rather contrived case, it's possible to race here so
3837	* reset the state to BTRFS_TRIM_STATE_UNTRIMMED.
3838	*
3839	* start = start of bitmap
3840	* end = near end of bitmap
3841	*
3842	* Thread 1: Thread 2:
3843	* trim_bitmaps(start)
3844	* trim_bitmaps(end)
3845	* end_trimming_bitmap()
3846	* reset_trimming_bitmap()
3847	*/
3848	static void reset_trimming_bitmap(struct btrfs_free_space_ctl *ctl, u64 offset)
3849	{
3850	struct btrfs_free_space *entry;
3851
3852	spin_lock(lock: &ctl->tree_lock);
3853	entry = tree_search_offset(ctl, offset, bitmap_only: 1, fuzzy: 0);
3854	if (entry) {
3855	if (btrfs_free_space_trimmed(info: entry)) {
3856	ctl->discardable_extents[BTRFS_STAT_CURR] +=
3857	entry->bitmap_extents;
3858	ctl->discardable_bytes[BTRFS_STAT_CURR] += entry->bytes;
3859	}
3860	entry->trim_state = BTRFS_TRIM_STATE_UNTRIMMED;
3861	}
3862
3863	spin_unlock(lock: &ctl->tree_lock);
3864	}
3865
3866	static void end_trimming_bitmap(struct btrfs_free_space_ctl *ctl,
3867	struct btrfs_free_space *entry)
3868	{
3869	if (btrfs_free_space_trimming_bitmap(info: entry)) {
3870	entry->trim_state = BTRFS_TRIM_STATE_TRIMMED;
3871	ctl->discardable_extents[BTRFS_STAT_CURR] -=
3872	entry->bitmap_extents;
3873	ctl->discardable_bytes[BTRFS_STAT_CURR] -= entry->bytes;
3874	}
3875	}
3876
3877	/*
3878	* If @async is set, then we will trim 1 region and return.
3879	*/
3880	static int trim_bitmaps(struct btrfs_block_group *block_group,
3881	u64 *total_trimmed, u64 start, u64 end, u64 minlen,
3882	u64 maxlen, bool async)
3883	{
3884	struct btrfs_discard_ctl *discard_ctl =
3885	&block_group->fs_info->discard_ctl;
3886	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
3887	struct btrfs_free_space *entry;
3888	int ret = 0;
3889	int ret2;
3890	u64 bytes;
3891	u64 offset = offset_to_bitmap(ctl, offset: start);
3892	const u64 max_discard_size = READ_ONCE(discard_ctl->max_discard_size);
3893
3894	while (offset < end) {
3895	bool next_bitmap = false;
3896	struct btrfs_trim_range trim_entry;
3897
3898	mutex_lock(&ctl->cache_writeout_mutex);
3899	spin_lock(lock: &ctl->tree_lock);
3900
3901	if (ctl->free_space < minlen) {
3902	block_group->discard_cursor =
3903	btrfs_block_group_end(block_group);
3904	spin_unlock(lock: &ctl->tree_lock);
3905	mutex_unlock(lock: &ctl->cache_writeout_mutex);
3906	break;
3907	}
3908
3909	entry = tree_search_offset(ctl, offset, bitmap_only: 1, fuzzy: 0);
3910	/*
3911	* Bitmaps are marked trimmed lossily now to prevent constant
3912	* discarding of the same bitmap (the reason why we are bound
3913	* by the filters). So, retrim the block group bitmaps when we
3914	* are preparing to punt to the unused_bgs list. This uses
3915	* @minlen to determine if we are in BTRFS_DISCARD_INDEX_UNUSED
3916	* which is the only discard index which sets minlen to 0.
3917	*/
3918	if (!entry || (async && minlen && start == offset &&
3919	btrfs_free_space_trimmed(info: entry))) {
3920	spin_unlock(lock: &ctl->tree_lock);
3921	mutex_unlock(lock: &ctl->cache_writeout_mutex);
3922	next_bitmap = true;
3923	goto next;
3924	}
3925
3926	/*
3927	* Async discard bitmap trimming begins at by setting the start
3928	* to be key.objectid and the offset_to_bitmap() aligns to the
3929	* start of the bitmap. This lets us know we are fully
3930	* scanning the bitmap rather than only some portion of it.
3931	*/
3932	if (start == offset)
3933	entry->trim_state = BTRFS_TRIM_STATE_TRIMMING;
3934
3935	bytes = minlen;
3936	ret2 = search_bitmap(ctl, bitmap_info: entry, offset: &start, bytes: &bytes, for_alloc: false);
3937	if (ret2 || start >= end) {
3938	/*
3939	* We lossily consider a bitmap trimmed if we only skip
3940	* over regions <= BTRFS_ASYNC_DISCARD_MIN_FILTER.
3941	*/
3942	if (ret2 && minlen <= BTRFS_ASYNC_DISCARD_MIN_FILTER)
3943	end_trimming_bitmap(ctl, entry);
3944	else
3945	entry->trim_state = BTRFS_TRIM_STATE_UNTRIMMED;
3946	spin_unlock(lock: &ctl->tree_lock);
3947	mutex_unlock(lock: &ctl->cache_writeout_mutex);
3948	next_bitmap = true;
3949	goto next;
3950	}
3951
3952	/*
3953	* We already trimmed a region, but are using the locking above
3954	* to reset the trim_state.
3955	*/
3956	if (async && *total_trimmed) {
3957	spin_unlock(lock: &ctl->tree_lock);
3958	mutex_unlock(lock: &ctl->cache_writeout_mutex);
3959	goto out;
3960	}
3961
3962	bytes = min(bytes, end - start);
3963	if (bytes < minlen || (async && maxlen && bytes > maxlen)) {
3964	spin_unlock(lock: &ctl->tree_lock);
3965	mutex_unlock(lock: &ctl->cache_writeout_mutex);
3966	goto next;
3967	}
3968
3969	/*
3970	* Let bytes = BTRFS_MAX_DISCARD_SIZE + X.
3971	* If X < @minlen, we won't trim X when we come back around.
3972	* So trim it now. We differ here from trimming extents as we
3973	* don't keep individual state per bit.
3974	*/
3975	if (async &&
3976	max_discard_size &&
3977	bytes > (max_discard_size + minlen))
3978	bytes = max_discard_size;
3979
3980	bitmap_clear_bits(ctl, info: entry, offset: start, bytes, update_stat: true);
3981	if (entry->bytes == 0)
3982	free_bitmap(ctl, bitmap_info: entry);
3983
3984	spin_unlock(lock: &ctl->tree_lock);
3985	trim_entry.start = start;
3986	trim_entry.bytes = bytes;
3987	list_add_tail(new: &trim_entry.list, head: &ctl->trimming_ranges);
3988	mutex_unlock(lock: &ctl->cache_writeout_mutex);
3989
3990	ret = do_trimming(block_group, total_trimmed, start, bytes,
3991	reserved_start: start, reserved_bytes: bytes, reserved_trim_state: 0, trim_entry: &trim_entry);
3992	if (ret) {
3993	reset_trimming_bitmap(ctl, offset);
3994	block_group->discard_cursor =
3995	btrfs_block_group_end(block_group);
3996	break;
3997	}
3998	next:
3999	if (next_bitmap) {
4000	offset += BITS_PER_BITMAP * ctl->unit;
4001	start = offset;
4002	} else {
4003	start += bytes;
4004	}
4005	block_group->discard_cursor = start;
4006
4007	if (btrfs_trim_interrupted()) {
4008	if (start != offset)
4009	reset_trimming_bitmap(ctl, offset);
4010	ret = -ERESTARTSYS;
4011	break;
4012	}
4013
4014	cond_resched();
4015	}
4016
4017	if (offset >= end)
4018	block_group->discard_cursor = end;
4019
4020	out:
4021	return ret;
4022	}
4023
4024	int btrfs_trim_block_group(struct btrfs_block_group *block_group,
4025	u64 *trimmed, u64 start, u64 end, u64 minlen)
4026	{
4027	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
4028	int ret;
4029	u64 rem = 0;
4030
4031	ASSERT(!btrfs_is_zoned(block_group->fs_info));
4032
4033	*trimmed = 0;
4034
4035	spin_lock(lock: &block_group->lock);
4036	if (test_bit(BLOCK_GROUP_FLAG_REMOVED, &block_group->runtime_flags)) {
4037	spin_unlock(lock: &block_group->lock);
4038	return 0;
4039	}
4040	btrfs_freeze_block_group(cache: block_group);
4041	spin_unlock(lock: &block_group->lock);
4042
4043	ret = trim_no_bitmap(block_group, total_trimmed: trimmed, start, end, minlen, async: false);
4044	if (ret)
4045	goto out;
4046
4047	ret = trim_bitmaps(block_group, total_trimmed: trimmed, start, end, minlen, maxlen: 0, async: false);
4048	div64_u64_rem(dividend: end, BITS_PER_BITMAP * ctl->unit, remainder: &rem);
4049	/* If we ended in the middle of a bitmap, reset the trimming flag */
4050	if (rem)
4051	reset_trimming_bitmap(ctl, offset: offset_to_bitmap(ctl, offset: end));
4052	out:
4053	btrfs_unfreeze_block_group(cache: block_group);
4054	return ret;
4055	}
4056
4057	int btrfs_trim_block_group_extents(struct btrfs_block_group *block_group,
4058	u64 *trimmed, u64 start, u64 end, u64 minlen,
4059	bool async)
4060	{
4061	int ret;
4062
4063	*trimmed = 0;
4064
4065	spin_lock(lock: &block_group->lock);
4066	if (test_bit(BLOCK_GROUP_FLAG_REMOVED, &block_group->runtime_flags)) {
4067	spin_unlock(lock: &block_group->lock);
4068	return 0;
4069	}
4070	btrfs_freeze_block_group(cache: block_group);
4071	spin_unlock(lock: &block_group->lock);
4072
4073	ret = trim_no_bitmap(block_group, total_trimmed: trimmed, start, end, minlen, async);
4074	btrfs_unfreeze_block_group(cache: block_group);
4075
4076	return ret;
4077	}
4078
4079	int btrfs_trim_block_group_bitmaps(struct btrfs_block_group *block_group,
4080	u64 *trimmed, u64 start, u64 end, u64 minlen,
4081	u64 maxlen, bool async)
4082	{
4083	int ret;
4084
4085	*trimmed = 0;
4086
4087	spin_lock(lock: &block_group->lock);
4088	if (test_bit(BLOCK_GROUP_FLAG_REMOVED, &block_group->runtime_flags)) {
4089	spin_unlock(lock: &block_group->lock);
4090	return 0;
4091	}
4092	btrfs_freeze_block_group(cache: block_group);
4093	spin_unlock(lock: &block_group->lock);
4094
4095	ret = trim_bitmaps(block_group, total_trimmed: trimmed, start, end, minlen, maxlen,
4096	async);
4097
4098	btrfs_unfreeze_block_group(cache: block_group);
4099
4100	return ret;
4101	}
4102
4103	bool btrfs_free_space_cache_v1_active(struct btrfs_fs_info *fs_info)
4104	{
4105	return btrfs_super_cache_generation(s: fs_info->super_copy);
4106	}
4107
4108	static int cleanup_free_space_cache_v1(struct btrfs_fs_info *fs_info,
4109	struct btrfs_trans_handle *trans)
4110	{
4111	struct btrfs_block_group *block_group;
4112	struct rb_node *node;
4113	int ret = 0;
4114
4115	btrfs_info(fs_info, "cleaning free space cache v1");
4116
4117	node = rb_first_cached(&fs_info->block_group_cache_tree);
4118	while (node) {
4119	block_group = rb_entry(node, struct btrfs_block_group, cache_node);
4120	ret = btrfs_remove_free_space_inode(trans, NULL, block_group);
4121	if (ret)
4122	goto out;
4123	node = rb_next(node);
4124	}
4125	out:
4126	return ret;
4127	}
4128
4129	int btrfs_set_free_space_cache_v1_active(struct btrfs_fs_info *fs_info, bool active)
4130	{
4131	struct btrfs_trans_handle *trans;
4132	int ret;
4133
4134	/*
4135	* update_super_roots will appropriately set or unset
4136	* super_copy->cache_generation based on SPACE_CACHE and
4137	* BTRFS_FS_CLEANUP_SPACE_CACHE_V1. For this reason, we need a
4138	* transaction commit whether we are enabling space cache v1 and don't
4139	* have any other work to do, or are disabling it and removing free
4140	* space inodes.
4141	*/
4142	trans = btrfs_start_transaction(root: fs_info->tree_root, num_items: 0);
4143	if (IS_ERR(ptr: trans))
4144	return PTR_ERR(ptr: trans);
4145
4146	if (!active) {
4147	set_bit(nr: BTRFS_FS_CLEANUP_SPACE_CACHE_V1, addr: &fs_info->flags);
4148	ret = cleanup_free_space_cache_v1(fs_info, trans);
4149	if (unlikely(ret)) {
4150	btrfs_abort_transaction(trans, ret);
4151	btrfs_end_transaction(trans);
4152	goto out;
4153	}
4154	}
4155
4156	ret = btrfs_commit_transaction(trans);
4157	out:
4158	clear_bit(nr: BTRFS_FS_CLEANUP_SPACE_CACHE_V1, addr: &fs_info->flags);
4159
4160	return ret;
4161	}
4162
4163	int __init btrfs_free_space_init(void)
4164	{
4165	btrfs_free_space_cachep = KMEM_CACHE(btrfs_free_space, 0);
4166	if (!btrfs_free_space_cachep)
4167	return -ENOMEM;
4168
4169	btrfs_free_space_bitmap_cachep = kmem_cache_create("btrfs_free_space_bitmap",
4170	PAGE_SIZE, PAGE_SIZE,
4171	0, NULL);
4172	if (!btrfs_free_space_bitmap_cachep) {
4173	kmem_cache_destroy(s: btrfs_free_space_cachep);
4174	return -ENOMEM;
4175	}
4176
4177	return 0;
4178	}
4179
4180	void __cold btrfs_free_space_exit(void)
4181	{
4182	kmem_cache_destroy(s: btrfs_free_space_cachep);
4183	kmem_cache_destroy(s: btrfs_free_space_bitmap_cachep);
4184	}
4185
4186	#ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
4187	/*
4188	* Use this if you need to make a bitmap or extent entry specifically, it
4189	* doesn't do any of the merging that add_free_space does, this acts a lot like
4190	* how the free space cache loading stuff works, so you can get really weird
4191	* configurations.
4192	*/
4193	int test_add_free_space_entry(struct btrfs_block_group *cache,
4194	u64 offset, u64 bytes, bool bitmap)
4195	{
4196	struct btrfs_free_space_ctl *ctl = cache->free_space_ctl;
4197	struct btrfs_free_space *info = NULL, *bitmap_info;
4198	void *map = NULL;
4199	enum btrfs_trim_state trim_state = BTRFS_TRIM_STATE_TRIMMED;
4200	u64 bytes_added;
4201	int ret;
4202
4203	again:
4204	if (!info) {
4205	info = kmem_cache_zalloc(btrfs_free_space_cachep, GFP_NOFS);
4206	if (!info)
4207	return -ENOMEM;
4208	}
4209
4210	if (!bitmap) {
4211	spin_lock(lock: &ctl->tree_lock);
4212	info->offset = offset;
4213	info->bytes = bytes;
4214	info->max_extent_size = 0;
4215	ret = link_free_space(ctl, info);
4216	spin_unlock(lock: &ctl->tree_lock);
4217	if (ret)
4218	kmem_cache_free(s: btrfs_free_space_cachep, objp: info);
4219	return ret;
4220	}
4221
4222	if (!map) {
4223	map = kmem_cache_zalloc(btrfs_free_space_bitmap_cachep, GFP_NOFS);
4224	if (!map) {
4225	kmem_cache_free(s: btrfs_free_space_cachep, objp: info);
4226	return -ENOMEM;
4227	}
4228	}
4229
4230	spin_lock(lock: &ctl->tree_lock);
4231	bitmap_info = tree_search_offset(ctl, offset: offset_to_bitmap(ctl, offset),
4232	bitmap_only: 1, fuzzy: 0);
4233	if (!bitmap_info) {
4234	info->bitmap = map;
4235	map = NULL;
4236	add_new_bitmap(ctl, info, offset);
4237	bitmap_info = info;
4238	info = NULL;
4239	}
4240
4241	bytes_added = add_bytes_to_bitmap(ctl, info: bitmap_info, offset, bytes,
4242	trim_state);
4243
4244	bytes -= bytes_added;
4245	offset += bytes_added;
4246	spin_unlock(lock: &ctl->tree_lock);
4247
4248	if (bytes)
4249	goto again;
4250
4251	if (info)
4252	kmem_cache_free(s: btrfs_free_space_cachep, objp: info);
4253	if (map)
4254	kmem_cache_free(s: btrfs_free_space_bitmap_cachep, objp: map);
4255	return 0;
4256	}
4257
4258	/*
4259	* Checks to see if the given range is in the free space cache. This is really
4260	* just used to check the absence of space, so if there is free space in the
4261	* range at all we will return 1.
4262	*/
4263	int test_check_exists(struct btrfs_block_group *cache,
4264	u64 offset, u64 bytes)
4265	{
4266	struct btrfs_free_space_ctl *ctl = cache->free_space_ctl;
4267	struct btrfs_free_space *info;
4268	int ret = 0;
4269
4270	spin_lock(lock: &ctl->tree_lock);
4271	info = tree_search_offset(ctl, offset, bitmap_only: 0, fuzzy: 0);
4272	if (!info) {
4273	info = tree_search_offset(ctl, offset: offset_to_bitmap(ctl, offset),
4274	bitmap_only: 1, fuzzy: 0);
4275	if (!info)
4276	goto out;
4277	}
4278
4279	have_info:
4280	if (info->bitmap) {
4281	u64 bit_off, bit_bytes;
4282	struct rb_node *n;
4283	struct btrfs_free_space *tmp;
4284
4285	bit_off = offset;
4286	bit_bytes = ctl->unit;
4287	ret = search_bitmap(ctl, bitmap_info: info, offset: &bit_off, bytes: &bit_bytes, for_alloc: false);
4288	if (!ret) {
4289	if (bit_off == offset) {
4290	ret = 1;
4291	goto out;
4292	} else if (bit_off > offset &&
4293	offset + bytes > bit_off) {
4294	ret = 1;
4295	goto out;
4296	}
4297	}
4298
4299	n = rb_prev(&info->offset_index);
4300	while (n) {
4301	tmp = rb_entry(n, struct btrfs_free_space,
4302	offset_index);
4303	if (tmp->offset + tmp->bytes < offset)
4304	break;
4305	if (offset + bytes < tmp->offset) {
4306	n = rb_prev(&tmp->offset_index);
4307	continue;
4308	}
4309	info = tmp;
4310	goto have_info;
4311	}
4312
4313	n = rb_next(&info->offset_index);
4314	while (n) {
4315	tmp = rb_entry(n, struct btrfs_free_space,
4316	offset_index);
4317	if (offset + bytes < tmp->offset)
4318	break;
4319	if (tmp->offset + tmp->bytes < offset) {
4320	n = rb_next(&tmp->offset_index);
4321	continue;
4322	}
4323	info = tmp;
4324	goto have_info;
4325	}
4326
4327	ret = 0;
4328	goto out;
4329	}
4330
4331	if (info->offset == offset) {
4332	ret = 1;
4333	goto out;
4334	}
4335
4336	if (offset > info->offset && offset < info->offset + info->bytes)
4337	ret = 1;
4338	out:
4339	spin_unlock(lock: &ctl->tree_lock);
4340	return ret;
4341	}
4342	#endif /* CONFIG_BTRFS_FS_RUN_SANITY_TESTS */
4343