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