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 "misc.h"
15 #include "ctree.h"
16 #include "free-space-cache.h"
17 #include "transaction.h"
18 #include "disk-io.h"
19 #include "extent_io.h"
20 #include "volumes.h"
21 #include "space-info.h"
22 #include "delalloc-space.h"
23 #include "block-group.h"
24 #include "discard.h"
25 #include "subpage.h"
26 #include "inode-item.h"
27 
28 #define BITS_PER_BITMAP		(PAGE_SIZE * 8UL)
29 #define MAX_CACHE_BYTES_PER_GIG	SZ_64K
30 #define FORCE_EXTENT_THRESHOLD	SZ_1M
31 
32 struct btrfs_trim_range {
33 	u64 start;
34 	u64 bytes;
35 	struct list_head list;
36 };
37 
38 static int link_free_space(struct btrfs_free_space_ctl *ctl,
39 			   struct btrfs_free_space *info);
40 static void unlink_free_space(struct btrfs_free_space_ctl *ctl,
41 			      struct btrfs_free_space *info, bool update_stat);
42 static int search_bitmap(struct btrfs_free_space_ctl *ctl,
43 			 struct btrfs_free_space *bitmap_info, u64 *offset,
44 			 u64 *bytes, bool for_alloc);
45 static void free_bitmap(struct btrfs_free_space_ctl *ctl,
46 			struct btrfs_free_space *bitmap_info);
47 static void bitmap_clear_bits(struct btrfs_free_space_ctl *ctl,
48 			      struct btrfs_free_space *info, u64 offset,
49 			      u64 bytes, bool update_stats);
50 
__btrfs_remove_free_space_cache(struct btrfs_free_space_ctl * ctl)51 static void __btrfs_remove_free_space_cache(struct btrfs_free_space_ctl *ctl)
52 {
53 	struct btrfs_free_space *info;
54 	struct rb_node *node;
55 
56 	while ((node = rb_last(&ctl->free_space_offset)) != NULL) {
57 		info = rb_entry(node, struct btrfs_free_space, offset_index);
58 		if (!info->bitmap) {
59 			unlink_free_space(ctl, info, true);
60 			kmem_cache_free(btrfs_free_space_cachep, info);
61 		} else {
62 			free_bitmap(ctl, info);
63 		}
64 
65 		cond_resched_lock(&ctl->tree_lock);
66 	}
67 }
68 
__lookup_free_space_inode(struct btrfs_root * root,struct btrfs_path * path,u64 offset)69 static struct inode *__lookup_free_space_inode(struct btrfs_root *root,
70 					       struct btrfs_path *path,
71 					       u64 offset)
72 {
73 	struct btrfs_fs_info *fs_info = root->fs_info;
74 	struct btrfs_key key;
75 	struct btrfs_key location;
76 	struct btrfs_disk_key disk_key;
77 	struct btrfs_free_space_header *header;
78 	struct extent_buffer *leaf;
79 	struct inode *inode = NULL;
80 	unsigned nofs_flag;
81 	int ret;
82 
83 	key.objectid = BTRFS_FREE_SPACE_OBJECTID;
84 	key.offset = offset;
85 	key.type = 0;
86 
87 	ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
88 	if (ret < 0)
89 		return ERR_PTR(ret);
90 	if (ret > 0) {
91 		btrfs_release_path(path);
92 		return ERR_PTR(-ENOENT);
93 	}
94 
95 	leaf = path->nodes[0];
96 	header = btrfs_item_ptr(leaf, path->slots[0],
97 				struct btrfs_free_space_header);
98 	btrfs_free_space_key(leaf, header, &disk_key);
99 	btrfs_disk_key_to_cpu(&location, &disk_key);
100 	btrfs_release_path(path);
101 
102 	/*
103 	 * We are often under a trans handle at this point, so we need to make
104 	 * sure NOFS is set to keep us from deadlocking.
105 	 */
106 	nofs_flag = memalloc_nofs_save();
107 	inode = btrfs_iget_path(fs_info->sb, location.objectid, root, path);
108 	btrfs_release_path(path);
109 	memalloc_nofs_restore(nofs_flag);
110 	if (IS_ERR(inode))
111 		return inode;
112 
113 	mapping_set_gfp_mask(inode->i_mapping,
114 			mapping_gfp_constraint(inode->i_mapping,
115 			~(__GFP_FS | __GFP_HIGHMEM)));
116 
117 	return inode;
118 }
119 
lookup_free_space_inode(struct btrfs_block_group * block_group,struct btrfs_path * path)120 struct inode *lookup_free_space_inode(struct btrfs_block_group *block_group,
121 		struct btrfs_path *path)
122 {
123 	struct btrfs_fs_info *fs_info = block_group->fs_info;
124 	struct inode *inode = NULL;
125 	u32 flags = BTRFS_INODE_NODATASUM | BTRFS_INODE_NODATACOW;
126 
127 	spin_lock(&block_group->lock);
128 	if (block_group->inode)
129 		inode = igrab(block_group->inode);
130 	spin_unlock(&block_group->lock);
131 	if (inode)
132 		return inode;
133 
134 	inode = __lookup_free_space_inode(fs_info->tree_root, path,
135 					  block_group->start);
136 	if (IS_ERR(inode))
137 		return inode;
138 
139 	spin_lock(&block_group->lock);
140 	if (!((BTRFS_I(inode)->flags & flags) == flags)) {
141 		btrfs_info(fs_info, "Old style space inode found, converting.");
142 		BTRFS_I(inode)->flags |= BTRFS_INODE_NODATASUM |
143 			BTRFS_INODE_NODATACOW;
144 		block_group->disk_cache_state = BTRFS_DC_CLEAR;
145 	}
146 
147 	if (!test_and_set_bit(BLOCK_GROUP_FLAG_IREF, &block_group->runtime_flags))
148 		block_group->inode = igrab(inode);
149 	spin_unlock(&block_group->lock);
150 
151 	return inode;
152 }
153 
__create_free_space_inode(struct btrfs_root * root,struct btrfs_trans_handle * trans,struct btrfs_path * path,u64 ino,u64 offset)154 static int __create_free_space_inode(struct btrfs_root *root,
155 				     struct btrfs_trans_handle *trans,
156 				     struct btrfs_path *path,
157 				     u64 ino, u64 offset)
158 {
159 	struct btrfs_key key;
160 	struct btrfs_disk_key disk_key;
161 	struct btrfs_free_space_header *header;
162 	struct btrfs_inode_item *inode_item;
163 	struct extent_buffer *leaf;
164 	/* We inline CRCs for the free disk space cache */
165 	const u64 flags = BTRFS_INODE_NOCOMPRESS | BTRFS_INODE_PREALLOC |
166 			  BTRFS_INODE_NODATASUM | BTRFS_INODE_NODATACOW;
167 	int ret;
168 
169 	ret = btrfs_insert_empty_inode(trans, root, path, ino);
170 	if (ret)
171 		return ret;
172 
173 	leaf = path->nodes[0];
174 	inode_item = btrfs_item_ptr(leaf, path->slots[0],
175 				    struct btrfs_inode_item);
176 	btrfs_item_key(leaf, &disk_key, path->slots[0]);
177 	memzero_extent_buffer(leaf, (unsigned long)inode_item,
178 			     sizeof(*inode_item));
179 	btrfs_set_inode_generation(leaf, inode_item, trans->transid);
180 	btrfs_set_inode_size(leaf, inode_item, 0);
181 	btrfs_set_inode_nbytes(leaf, inode_item, 0);
182 	btrfs_set_inode_uid(leaf, inode_item, 0);
183 	btrfs_set_inode_gid(leaf, inode_item, 0);
184 	btrfs_set_inode_mode(leaf, inode_item, S_IFREG | 0600);
185 	btrfs_set_inode_flags(leaf, inode_item, flags);
186 	btrfs_set_inode_nlink(leaf, inode_item, 1);
187 	btrfs_set_inode_transid(leaf, inode_item, trans->transid);
188 	btrfs_set_inode_block_group(leaf, inode_item, offset);
189 	btrfs_mark_buffer_dirty(leaf);
190 	btrfs_release_path(path);
191 
192 	key.objectid = BTRFS_FREE_SPACE_OBJECTID;
193 	key.offset = offset;
194 	key.type = 0;
195 	ret = btrfs_insert_empty_item(trans, root, path, &key,
196 				      sizeof(struct btrfs_free_space_header));
197 	if (ret < 0) {
198 		btrfs_release_path(path);
199 		return ret;
200 	}
201 
202 	leaf = path->nodes[0];
203 	header = btrfs_item_ptr(leaf, path->slots[0],
204 				struct btrfs_free_space_header);
205 	memzero_extent_buffer(leaf, (unsigned long)header, sizeof(*header));
206 	btrfs_set_free_space_key(leaf, header, &disk_key);
207 	btrfs_mark_buffer_dirty(leaf);
208 	btrfs_release_path(path);
209 
210 	return 0;
211 }
212 
create_free_space_inode(struct btrfs_trans_handle * trans,struct btrfs_block_group * block_group,struct btrfs_path * path)213 int create_free_space_inode(struct btrfs_trans_handle *trans,
214 			    struct btrfs_block_group *block_group,
215 			    struct btrfs_path *path)
216 {
217 	int ret;
218 	u64 ino;
219 
220 	ret = btrfs_get_free_objectid(trans->fs_info->tree_root, &ino);
221 	if (ret < 0)
222 		return ret;
223 
224 	return __create_free_space_inode(trans->fs_info->tree_root, trans, path,
225 					 ino, block_group->start);
226 }
227 
228 /*
229  * inode is an optional sink: if it is NULL, btrfs_remove_free_space_inode
230  * handles lookup, otherwise it takes ownership and iputs the inode.
231  * Don't reuse an inode pointer after passing it into this function.
232  */
btrfs_remove_free_space_inode(struct btrfs_trans_handle * trans,struct inode * inode,struct btrfs_block_group * block_group)233 int btrfs_remove_free_space_inode(struct btrfs_trans_handle *trans,
234 				  struct inode *inode,
235 				  struct btrfs_block_group *block_group)
236 {
237 	struct btrfs_path *path;
238 	struct btrfs_key key;
239 	int ret = 0;
240 
241 	path = btrfs_alloc_path();
242 	if (!path)
243 		return -ENOMEM;
244 
245 	if (!inode)
246 		inode = lookup_free_space_inode(block_group, path);
247 	if (IS_ERR(inode)) {
248 		if (PTR_ERR(inode) != -ENOENT)
249 			ret = PTR_ERR(inode);
250 		goto out;
251 	}
252 	ret = btrfs_orphan_add(trans, BTRFS_I(inode));
253 	if (ret) {
254 		btrfs_add_delayed_iput(inode);
255 		goto out;
256 	}
257 	clear_nlink(inode);
258 	/* One for the block groups ref */
259 	spin_lock(&block_group->lock);
260 	if (test_and_clear_bit(BLOCK_GROUP_FLAG_IREF, &block_group->runtime_flags)) {
261 		block_group->inode = NULL;
262 		spin_unlock(&block_group->lock);
263 		iput(inode);
264 	} else {
265 		spin_unlock(&block_group->lock);
266 	}
267 	/* One for the lookup ref */
268 	btrfs_add_delayed_iput(inode);
269 
270 	key.objectid = BTRFS_FREE_SPACE_OBJECTID;
271 	key.type = 0;
272 	key.offset = block_group->start;
273 	ret = btrfs_search_slot(trans, trans->fs_info->tree_root, &key, path,
274 				-1, 1);
275 	if (ret) {
276 		if (ret > 0)
277 			ret = 0;
278 		goto out;
279 	}
280 	ret = btrfs_del_item(trans, trans->fs_info->tree_root, path);
281 out:
282 	btrfs_free_path(path);
283 	return ret;
284 }
285 
btrfs_check_trunc_cache_free_space(struct btrfs_fs_info * fs_info,struct btrfs_block_rsv * rsv)286 int btrfs_check_trunc_cache_free_space(struct btrfs_fs_info *fs_info,
287 				       struct btrfs_block_rsv *rsv)
288 {
289 	u64 needed_bytes;
290 	int ret;
291 
292 	/* 1 for slack space, 1 for updating the inode */
293 	needed_bytes = btrfs_calc_insert_metadata_size(fs_info, 1) +
294 		btrfs_calc_metadata_size(fs_info, 1);
295 
296 	spin_lock(&rsv->lock);
297 	if (rsv->reserved < needed_bytes)
298 		ret = -ENOSPC;
299 	else
300 		ret = 0;
301 	spin_unlock(&rsv->lock);
302 	return ret;
303 }
304 
btrfs_truncate_free_space_cache(struct btrfs_trans_handle * trans,struct btrfs_block_group * block_group,struct inode * vfs_inode)305 int btrfs_truncate_free_space_cache(struct btrfs_trans_handle *trans,
306 				    struct btrfs_block_group *block_group,
307 				    struct inode *vfs_inode)
308 {
309 	struct btrfs_truncate_control control = {
310 		.inode = BTRFS_I(vfs_inode),
311 		.new_size = 0,
312 		.ino = btrfs_ino(BTRFS_I(vfs_inode)),
313 		.min_type = BTRFS_EXTENT_DATA_KEY,
314 		.clear_extent_range = true,
315 	};
316 	struct btrfs_inode *inode = BTRFS_I(vfs_inode);
317 	struct btrfs_root *root = inode->root;
318 	struct extent_state *cached_state = NULL;
319 	int ret = 0;
320 	bool locked = false;
321 
322 	if (block_group) {
323 		struct btrfs_path *path = btrfs_alloc_path();
324 
325 		if (!path) {
326 			ret = -ENOMEM;
327 			goto fail;
328 		}
329 		locked = true;
330 		mutex_lock(&trans->transaction->cache_write_mutex);
331 		if (!list_empty(&block_group->io_list)) {
332 			list_del_init(&block_group->io_list);
333 
334 			btrfs_wait_cache_io(trans, block_group, path);
335 			btrfs_put_block_group(block_group);
336 		}
337 
338 		/*
339 		 * now that we've truncated the cache away, its no longer
340 		 * setup or written
341 		 */
342 		spin_lock(&block_group->lock);
343 		block_group->disk_cache_state = BTRFS_DC_CLEAR;
344 		spin_unlock(&block_group->lock);
345 		btrfs_free_path(path);
346 	}
347 
348 	btrfs_i_size_write(inode, 0);
349 	truncate_pagecache(vfs_inode, 0);
350 
351 	lock_extent(&inode->io_tree, 0, (u64)-1, &cached_state);
352 	btrfs_drop_extent_map_range(inode, 0, (u64)-1, false);
353 
354 	/*
355 	 * We skip the throttling logic for free space cache inodes, so we don't
356 	 * need to check for -EAGAIN.
357 	 */
358 	ret = btrfs_truncate_inode_items(trans, root, &control);
359 
360 	inode_sub_bytes(&inode->vfs_inode, control.sub_bytes);
361 	btrfs_inode_safe_disk_i_size_write(inode, control.last_size);
362 
363 	unlock_extent(&inode->io_tree, 0, (u64)-1, &cached_state);
364 	if (ret)
365 		goto fail;
366 
367 	ret = btrfs_update_inode(trans, root, inode);
368 
369 fail:
370 	if (locked)
371 		mutex_unlock(&trans->transaction->cache_write_mutex);
372 	if (ret)
373 		btrfs_abort_transaction(trans, ret);
374 
375 	return ret;
376 }
377 
readahead_cache(struct inode * inode)378 static void readahead_cache(struct inode *inode)
379 {
380 	struct file_ra_state ra;
381 	unsigned long last_index;
382 
383 	file_ra_state_init(&ra, inode->i_mapping);
384 	last_index = (i_size_read(inode) - 1) >> PAGE_SHIFT;
385 
386 	page_cache_sync_readahead(inode->i_mapping, &ra, NULL, 0, last_index);
387 }
388 
io_ctl_init(struct btrfs_io_ctl * io_ctl,struct inode * inode,int write)389 static int io_ctl_init(struct btrfs_io_ctl *io_ctl, struct inode *inode,
390 		       int write)
391 {
392 	int num_pages;
393 
394 	num_pages = DIV_ROUND_UP(i_size_read(inode), PAGE_SIZE);
395 
396 	/* Make sure we can fit our crcs and generation into the first page */
397 	if (write && (num_pages * sizeof(u32) + sizeof(u64)) > PAGE_SIZE)
398 		return -ENOSPC;
399 
400 	memset(io_ctl, 0, sizeof(struct btrfs_io_ctl));
401 
402 	io_ctl->pages = kcalloc(num_pages, sizeof(struct page *), GFP_NOFS);
403 	if (!io_ctl->pages)
404 		return -ENOMEM;
405 
406 	io_ctl->num_pages = num_pages;
407 	io_ctl->fs_info = btrfs_sb(inode->i_sb);
408 	io_ctl->inode = inode;
409 
410 	return 0;
411 }
412 ALLOW_ERROR_INJECTION(io_ctl_init, ERRNO);
413 
io_ctl_free(struct btrfs_io_ctl * io_ctl)414 static void io_ctl_free(struct btrfs_io_ctl *io_ctl)
415 {
416 	kfree(io_ctl->pages);
417 	io_ctl->pages = NULL;
418 }
419 
io_ctl_unmap_page(struct btrfs_io_ctl * io_ctl)420 static void io_ctl_unmap_page(struct btrfs_io_ctl *io_ctl)
421 {
422 	if (io_ctl->cur) {
423 		io_ctl->cur = NULL;
424 		io_ctl->orig = NULL;
425 	}
426 }
427 
io_ctl_map_page(struct btrfs_io_ctl * io_ctl,int clear)428 static void io_ctl_map_page(struct btrfs_io_ctl *io_ctl, int clear)
429 {
430 	ASSERT(io_ctl->index < io_ctl->num_pages);
431 	io_ctl->page = io_ctl->pages[io_ctl->index++];
432 	io_ctl->cur = page_address(io_ctl->page);
433 	io_ctl->orig = io_ctl->cur;
434 	io_ctl->size = PAGE_SIZE;
435 	if (clear)
436 		clear_page(io_ctl->cur);
437 }
438 
io_ctl_drop_pages(struct btrfs_io_ctl * io_ctl)439 static void io_ctl_drop_pages(struct btrfs_io_ctl *io_ctl)
440 {
441 	int i;
442 
443 	io_ctl_unmap_page(io_ctl);
444 
445 	for (i = 0; i < io_ctl->num_pages; i++) {
446 		if (io_ctl->pages[i]) {
447 			btrfs_page_clear_checked(io_ctl->fs_info,
448 					io_ctl->pages[i],
449 					page_offset(io_ctl->pages[i]),
450 					PAGE_SIZE);
451 			unlock_page(io_ctl->pages[i]);
452 			put_page(io_ctl->pages[i]);
453 		}
454 	}
455 }
456 
io_ctl_prepare_pages(struct btrfs_io_ctl * io_ctl,bool uptodate)457 static int io_ctl_prepare_pages(struct btrfs_io_ctl *io_ctl, bool uptodate)
458 {
459 	struct page *page;
460 	struct inode *inode = io_ctl->inode;
461 	gfp_t mask = btrfs_alloc_write_mask(inode->i_mapping);
462 	int i;
463 
464 	for (i = 0; i < io_ctl->num_pages; i++) {
465 		int ret;
466 
467 		page = find_or_create_page(inode->i_mapping, i, mask);
468 		if (!page) {
469 			io_ctl_drop_pages(io_ctl);
470 			return -ENOMEM;
471 		}
472 
473 		ret = set_page_extent_mapped(page);
474 		if (ret < 0) {
475 			unlock_page(page);
476 			put_page(page);
477 			io_ctl_drop_pages(io_ctl);
478 			return ret;
479 		}
480 
481 		io_ctl->pages[i] = page;
482 		if (uptodate && !PageUptodate(page)) {
483 			btrfs_read_folio(NULL, page_folio(page));
484 			lock_page(page);
485 			if (page->mapping != inode->i_mapping) {
486 				btrfs_err(BTRFS_I(inode)->root->fs_info,
487 					  "free space cache page truncated");
488 				io_ctl_drop_pages(io_ctl);
489 				return -EIO;
490 			}
491 			if (!PageUptodate(page)) {
492 				btrfs_err(BTRFS_I(inode)->root->fs_info,
493 					   "error reading free space cache");
494 				io_ctl_drop_pages(io_ctl);
495 				return -EIO;
496 			}
497 		}
498 	}
499 
500 	for (i = 0; i < io_ctl->num_pages; i++)
501 		clear_page_dirty_for_io(io_ctl->pages[i]);
502 
503 	return 0;
504 }
505 
io_ctl_set_generation(struct btrfs_io_ctl * io_ctl,u64 generation)506 static void io_ctl_set_generation(struct btrfs_io_ctl *io_ctl, u64 generation)
507 {
508 	io_ctl_map_page(io_ctl, 1);
509 
510 	/*
511 	 * Skip the csum areas.  If we don't check crcs then we just have a
512 	 * 64bit chunk at the front of the first page.
513 	 */
514 	io_ctl->cur += (sizeof(u32) * io_ctl->num_pages);
515 	io_ctl->size -= sizeof(u64) + (sizeof(u32) * io_ctl->num_pages);
516 
517 	put_unaligned_le64(generation, io_ctl->cur);
518 	io_ctl->cur += sizeof(u64);
519 }
520 
io_ctl_check_generation(struct btrfs_io_ctl * io_ctl,u64 generation)521 static int io_ctl_check_generation(struct btrfs_io_ctl *io_ctl, u64 generation)
522 {
523 	u64 cache_gen;
524 
525 	/*
526 	 * Skip the crc area.  If we don't check crcs then we just have a 64bit
527 	 * chunk at the front of the first page.
528 	 */
529 	io_ctl->cur += sizeof(u32) * io_ctl->num_pages;
530 	io_ctl->size -= sizeof(u64) + (sizeof(u32) * io_ctl->num_pages);
531 
532 	cache_gen = get_unaligned_le64(io_ctl->cur);
533 	if (cache_gen != generation) {
534 		btrfs_err_rl(io_ctl->fs_info,
535 			"space cache generation (%llu) does not match inode (%llu)",
536 				cache_gen, generation);
537 		io_ctl_unmap_page(io_ctl);
538 		return -EIO;
539 	}
540 	io_ctl->cur += sizeof(u64);
541 	return 0;
542 }
543 
io_ctl_set_crc(struct btrfs_io_ctl * io_ctl,int index)544 static void io_ctl_set_crc(struct btrfs_io_ctl *io_ctl, int index)
545 {
546 	u32 *tmp;
547 	u32 crc = ~(u32)0;
548 	unsigned offset = 0;
549 
550 	if (index == 0)
551 		offset = sizeof(u32) * io_ctl->num_pages;
552 
553 	crc = btrfs_crc32c(crc, io_ctl->orig + offset, PAGE_SIZE - offset);
554 	btrfs_crc32c_final(crc, (u8 *)&crc);
555 	io_ctl_unmap_page(io_ctl);
556 	tmp = page_address(io_ctl->pages[0]);
557 	tmp += index;
558 	*tmp = crc;
559 }
560 
io_ctl_check_crc(struct btrfs_io_ctl * io_ctl,int index)561 static int io_ctl_check_crc(struct btrfs_io_ctl *io_ctl, int index)
562 {
563 	u32 *tmp, val;
564 	u32 crc = ~(u32)0;
565 	unsigned offset = 0;
566 
567 	if (index == 0)
568 		offset = sizeof(u32) * io_ctl->num_pages;
569 
570 	tmp = page_address(io_ctl->pages[0]);
571 	tmp += index;
572 	val = *tmp;
573 
574 	io_ctl_map_page(io_ctl, 0);
575 	crc = btrfs_crc32c(crc, io_ctl->orig + offset, PAGE_SIZE - offset);
576 	btrfs_crc32c_final(crc, (u8 *)&crc);
577 	if (val != crc) {
578 		btrfs_err_rl(io_ctl->fs_info,
579 			"csum mismatch on free space cache");
580 		io_ctl_unmap_page(io_ctl);
581 		return -EIO;
582 	}
583 
584 	return 0;
585 }
586 
io_ctl_add_entry(struct btrfs_io_ctl * io_ctl,u64 offset,u64 bytes,void * bitmap)587 static int io_ctl_add_entry(struct btrfs_io_ctl *io_ctl, u64 offset, u64 bytes,
588 			    void *bitmap)
589 {
590 	struct btrfs_free_space_entry *entry;
591 
592 	if (!io_ctl->cur)
593 		return -ENOSPC;
594 
595 	entry = io_ctl->cur;
596 	put_unaligned_le64(offset, &entry->offset);
597 	put_unaligned_le64(bytes, &entry->bytes);
598 	entry->type = (bitmap) ? BTRFS_FREE_SPACE_BITMAP :
599 		BTRFS_FREE_SPACE_EXTENT;
600 	io_ctl->cur += sizeof(struct btrfs_free_space_entry);
601 	io_ctl->size -= sizeof(struct btrfs_free_space_entry);
602 
603 	if (io_ctl->size >= sizeof(struct btrfs_free_space_entry))
604 		return 0;
605 
606 	io_ctl_set_crc(io_ctl, io_ctl->index - 1);
607 
608 	/* No more pages to map */
609 	if (io_ctl->index >= io_ctl->num_pages)
610 		return 0;
611 
612 	/* map the next page */
613 	io_ctl_map_page(io_ctl, 1);
614 	return 0;
615 }
616 
io_ctl_add_bitmap(struct btrfs_io_ctl * io_ctl,void * bitmap)617 static int io_ctl_add_bitmap(struct btrfs_io_ctl *io_ctl, void *bitmap)
618 {
619 	if (!io_ctl->cur)
620 		return -ENOSPC;
621 
622 	/*
623 	 * If we aren't at the start of the current page, unmap this one and
624 	 * map the next one if there is any left.
625 	 */
626 	if (io_ctl->cur != io_ctl->orig) {
627 		io_ctl_set_crc(io_ctl, io_ctl->index - 1);
628 		if (io_ctl->index >= io_ctl->num_pages)
629 			return -ENOSPC;
630 		io_ctl_map_page(io_ctl, 0);
631 	}
632 
633 	copy_page(io_ctl->cur, bitmap);
634 	io_ctl_set_crc(io_ctl, io_ctl->index - 1);
635 	if (io_ctl->index < io_ctl->num_pages)
636 		io_ctl_map_page(io_ctl, 0);
637 	return 0;
638 }
639 
io_ctl_zero_remaining_pages(struct btrfs_io_ctl * io_ctl)640 static void io_ctl_zero_remaining_pages(struct btrfs_io_ctl *io_ctl)
641 {
642 	/*
643 	 * If we're not on the boundary we know we've modified the page and we
644 	 * need to crc the page.
645 	 */
646 	if (io_ctl->cur != io_ctl->orig)
647 		io_ctl_set_crc(io_ctl, io_ctl->index - 1);
648 	else
649 		io_ctl_unmap_page(io_ctl);
650 
651 	while (io_ctl->index < io_ctl->num_pages) {
652 		io_ctl_map_page(io_ctl, 1);
653 		io_ctl_set_crc(io_ctl, io_ctl->index - 1);
654 	}
655 }
656 
io_ctl_read_entry(struct btrfs_io_ctl * io_ctl,struct btrfs_free_space * entry,u8 * type)657 static int io_ctl_read_entry(struct btrfs_io_ctl *io_ctl,
658 			    struct btrfs_free_space *entry, u8 *type)
659 {
660 	struct btrfs_free_space_entry *e;
661 	int ret;
662 
663 	if (!io_ctl->cur) {
664 		ret = io_ctl_check_crc(io_ctl, io_ctl->index);
665 		if (ret)
666 			return ret;
667 	}
668 
669 	e = io_ctl->cur;
670 	entry->offset = get_unaligned_le64(&e->offset);
671 	entry->bytes = get_unaligned_le64(&e->bytes);
672 	*type = e->type;
673 	io_ctl->cur += sizeof(struct btrfs_free_space_entry);
674 	io_ctl->size -= sizeof(struct btrfs_free_space_entry);
675 
676 	if (io_ctl->size >= sizeof(struct btrfs_free_space_entry))
677 		return 0;
678 
679 	io_ctl_unmap_page(io_ctl);
680 
681 	return 0;
682 }
683 
io_ctl_read_bitmap(struct btrfs_io_ctl * io_ctl,struct btrfs_free_space * entry)684 static int io_ctl_read_bitmap(struct btrfs_io_ctl *io_ctl,
685 			      struct btrfs_free_space *entry)
686 {
687 	int ret;
688 
689 	ret = io_ctl_check_crc(io_ctl, io_ctl->index);
690 	if (ret)
691 		return ret;
692 
693 	copy_page(entry->bitmap, io_ctl->cur);
694 	io_ctl_unmap_page(io_ctl);
695 
696 	return 0;
697 }
698 
recalculate_thresholds(struct btrfs_free_space_ctl * ctl)699 static void recalculate_thresholds(struct btrfs_free_space_ctl *ctl)
700 {
701 	struct btrfs_block_group *block_group = ctl->block_group;
702 	u64 max_bytes;
703 	u64 bitmap_bytes;
704 	u64 extent_bytes;
705 	u64 size = block_group->length;
706 	u64 bytes_per_bg = BITS_PER_BITMAP * ctl->unit;
707 	u64 max_bitmaps = div64_u64(size + bytes_per_bg - 1, bytes_per_bg);
708 
709 	max_bitmaps = max_t(u64, max_bitmaps, 1);
710 
711 	if (ctl->total_bitmaps > max_bitmaps)
712 		btrfs_err(block_group->fs_info,
713 "invalid free space control: bg start=%llu len=%llu total_bitmaps=%u unit=%u max_bitmaps=%llu bytes_per_bg=%llu",
714 			  block_group->start, block_group->length,
715 			  ctl->total_bitmaps, ctl->unit, max_bitmaps,
716 			  bytes_per_bg);
717 	ASSERT(ctl->total_bitmaps <= max_bitmaps);
718 
719 	/*
720 	 * We are trying to keep the total amount of memory used per 1GiB of
721 	 * space to be MAX_CACHE_BYTES_PER_GIG.  However, with a reclamation
722 	 * mechanism of pulling extents >= FORCE_EXTENT_THRESHOLD out of
723 	 * bitmaps, we may end up using more memory than this.
724 	 */
725 	if (size < SZ_1G)
726 		max_bytes = MAX_CACHE_BYTES_PER_GIG;
727 	else
728 		max_bytes = MAX_CACHE_BYTES_PER_GIG * div_u64(size, SZ_1G);
729 
730 	bitmap_bytes = ctl->total_bitmaps * ctl->unit;
731 
732 	/*
733 	 * we want the extent entry threshold to always be at most 1/2 the max
734 	 * bytes we can have, or whatever is less than that.
735 	 */
736 	extent_bytes = max_bytes - bitmap_bytes;
737 	extent_bytes = min_t(u64, extent_bytes, max_bytes >> 1);
738 
739 	ctl->extents_thresh =
740 		div_u64(extent_bytes, sizeof(struct btrfs_free_space));
741 }
742 
__load_free_space_cache(struct btrfs_root * root,struct inode * inode,struct btrfs_free_space_ctl * ctl,struct btrfs_path * path,u64 offset)743 static int __load_free_space_cache(struct btrfs_root *root, struct inode *inode,
744 				   struct btrfs_free_space_ctl *ctl,
745 				   struct btrfs_path *path, u64 offset)
746 {
747 	struct btrfs_fs_info *fs_info = root->fs_info;
748 	struct btrfs_free_space_header *header;
749 	struct extent_buffer *leaf;
750 	struct btrfs_io_ctl io_ctl;
751 	struct btrfs_key key;
752 	struct btrfs_free_space *e, *n;
753 	LIST_HEAD(bitmaps);
754 	u64 num_entries;
755 	u64 num_bitmaps;
756 	u64 generation;
757 	u8 type;
758 	int ret = 0;
759 
760 	/* Nothing in the space cache, goodbye */
761 	if (!i_size_read(inode))
762 		return 0;
763 
764 	key.objectid = BTRFS_FREE_SPACE_OBJECTID;
765 	key.offset = offset;
766 	key.type = 0;
767 
768 	ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
769 	if (ret < 0)
770 		return 0;
771 	else if (ret > 0) {
772 		btrfs_release_path(path);
773 		return 0;
774 	}
775 
776 	ret = -1;
777 
778 	leaf = path->nodes[0];
779 	header = btrfs_item_ptr(leaf, path->slots[0],
780 				struct btrfs_free_space_header);
781 	num_entries = btrfs_free_space_entries(leaf, header);
782 	num_bitmaps = btrfs_free_space_bitmaps(leaf, header);
783 	generation = btrfs_free_space_generation(leaf, header);
784 	btrfs_release_path(path);
785 
786 	if (!BTRFS_I(inode)->generation) {
787 		btrfs_info(fs_info,
788 			   "the free space cache file (%llu) is invalid, skip it",
789 			   offset);
790 		return 0;
791 	}
792 
793 	if (BTRFS_I(inode)->generation != generation) {
794 		btrfs_err(fs_info,
795 			  "free space inode generation (%llu) did not match free space cache generation (%llu)",
796 			  BTRFS_I(inode)->generation, generation);
797 		return 0;
798 	}
799 
800 	if (!num_entries)
801 		return 0;
802 
803 	ret = io_ctl_init(&io_ctl, inode, 0);
804 	if (ret)
805 		return ret;
806 
807 	readahead_cache(inode);
808 
809 	ret = io_ctl_prepare_pages(&io_ctl, true);
810 	if (ret)
811 		goto out;
812 
813 	ret = io_ctl_check_crc(&io_ctl, 0);
814 	if (ret)
815 		goto free_cache;
816 
817 	ret = io_ctl_check_generation(&io_ctl, generation);
818 	if (ret)
819 		goto free_cache;
820 
821 	while (num_entries) {
822 		e = kmem_cache_zalloc(btrfs_free_space_cachep,
823 				      GFP_NOFS);
824 		if (!e) {
825 			ret = -ENOMEM;
826 			goto free_cache;
827 		}
828 
829 		ret = io_ctl_read_entry(&io_ctl, e, &type);
830 		if (ret) {
831 			kmem_cache_free(btrfs_free_space_cachep, e);
832 			goto free_cache;
833 		}
834 
835 		if (!e->bytes) {
836 			ret = -1;
837 			kmem_cache_free(btrfs_free_space_cachep, e);
838 			goto free_cache;
839 		}
840 
841 		if (type == BTRFS_FREE_SPACE_EXTENT) {
842 			spin_lock(&ctl->tree_lock);
843 			ret = link_free_space(ctl, e);
844 			spin_unlock(&ctl->tree_lock);
845 			if (ret) {
846 				btrfs_err(fs_info,
847 					"Duplicate entries in free space cache, dumping");
848 				kmem_cache_free(btrfs_free_space_cachep, e);
849 				goto free_cache;
850 			}
851 		} else {
852 			ASSERT(num_bitmaps);
853 			num_bitmaps--;
854 			e->bitmap = kmem_cache_zalloc(
855 					btrfs_free_space_bitmap_cachep, GFP_NOFS);
856 			if (!e->bitmap) {
857 				ret = -ENOMEM;
858 				kmem_cache_free(
859 					btrfs_free_space_cachep, e);
860 				goto free_cache;
861 			}
862 			spin_lock(&ctl->tree_lock);
863 			ret = link_free_space(ctl, e);
864 			ctl->total_bitmaps++;
865 			recalculate_thresholds(ctl);
866 			spin_unlock(&ctl->tree_lock);
867 			if (ret) {
868 				btrfs_err(fs_info,
869 					"Duplicate entries in free space cache, dumping");
870 				kmem_cache_free(btrfs_free_space_cachep, e);
871 				goto free_cache;
872 			}
873 			list_add_tail(&e->list, &bitmaps);
874 		}
875 
876 		num_entries--;
877 	}
878 
879 	io_ctl_unmap_page(&io_ctl);
880 
881 	/*
882 	 * We add the bitmaps at the end of the entries in order that
883 	 * the bitmap entries are added to the cache.
884 	 */
885 	list_for_each_entry_safe(e, n, &bitmaps, list) {
886 		list_del_init(&e->list);
887 		ret = io_ctl_read_bitmap(&io_ctl, e);
888 		if (ret)
889 			goto free_cache;
890 	}
891 
892 	io_ctl_drop_pages(&io_ctl);
893 	ret = 1;
894 out:
895 	io_ctl_free(&io_ctl);
896 	return ret;
897 free_cache:
898 	io_ctl_drop_pages(&io_ctl);
899 
900 	spin_lock(&ctl->tree_lock);
901 	__btrfs_remove_free_space_cache(ctl);
902 	spin_unlock(&ctl->tree_lock);
903 	goto out;
904 }
905 
copy_free_space_cache(struct btrfs_block_group * block_group,struct btrfs_free_space_ctl * ctl)906 static int copy_free_space_cache(struct btrfs_block_group *block_group,
907 				 struct btrfs_free_space_ctl *ctl)
908 {
909 	struct btrfs_free_space *info;
910 	struct rb_node *n;
911 	int ret = 0;
912 
913 	while (!ret && (n = rb_first(&ctl->free_space_offset)) != NULL) {
914 		info = rb_entry(n, struct btrfs_free_space, offset_index);
915 		if (!info->bitmap) {
916 			unlink_free_space(ctl, info, true);
917 			ret = btrfs_add_free_space(block_group, info->offset,
918 						   info->bytes);
919 			kmem_cache_free(btrfs_free_space_cachep, info);
920 		} else {
921 			u64 offset = info->offset;
922 			u64 bytes = ctl->unit;
923 
924 			while (search_bitmap(ctl, info, &offset, &bytes,
925 					     false) == 0) {
926 				ret = btrfs_add_free_space(block_group, offset,
927 							   bytes);
928 				if (ret)
929 					break;
930 				bitmap_clear_bits(ctl, info, offset, bytes, true);
931 				offset = info->offset;
932 				bytes = ctl->unit;
933 			}
934 			free_bitmap(ctl, info);
935 		}
936 		cond_resched();
937 	}
938 	return ret;
939 }
940 
941 static struct lock_class_key btrfs_free_space_inode_key;
942 
load_free_space_cache(struct btrfs_block_group * block_group)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, &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(&block_group->lock);
966 	if (block_group->disk_cache_state != BTRFS_DC_WRITTEN) {
967 		spin_unlock(&block_group->lock);
968 		return 0;
969 	}
970 	spin_unlock(&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(inode)) {
999 		btrfs_free_path(path);
1000 		return 0;
1001 	}
1002 
1003 	/* We may have converted the inode and made the cache invalid. */
1004 	spin_lock(&block_group->lock);
1005 	if (block_group->disk_cache_state != BTRFS_DC_WRITTEN) {
1006 		spin_unlock(&block_group->lock);
1007 		btrfs_free_path(path);
1008 		goto out;
1009 	}
1010 	spin_unlock(&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(fs_info->tree_root, inode, &tmp_ctl,
1021 				      path, block_group->start);
1022 	btrfs_free_path(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 		ret = copy_free_space_cache(block_group, &tmp_ctl);
1031 		/*
1032 		 * ret == 1 means we successfully loaded the free space cache,
1033 		 * so we need to re-set it here.
1034 		 */
1035 		if (ret == 0)
1036 			ret = 1;
1037 	} else {
1038 		/*
1039 		 * We need to call the _locked variant so we don't try to update
1040 		 * the discard counters.
1041 		 */
1042 		spin_lock(&tmp_ctl.tree_lock);
1043 		__btrfs_remove_free_space_cache(&tmp_ctl);
1044 		spin_unlock(&tmp_ctl.tree_lock);
1045 		btrfs_warn(fs_info,
1046 			   "block group %llu has wrong amount of free space",
1047 			   block_group->start);
1048 		ret = -1;
1049 	}
1050 out:
1051 	if (ret < 0) {
1052 		/* This cache is bogus, make sure it gets cleared */
1053 		spin_lock(&block_group->lock);
1054 		block_group->disk_cache_state = BTRFS_DC_CLEAR;
1055 		spin_unlock(&block_group->lock);
1056 		ret = 0;
1057 
1058 		btrfs_warn(fs_info,
1059 			   "failed to load free space cache for block group %llu, rebuilding it now",
1060 			   block_group->start);
1061 	}
1062 
1063 	spin_lock(&ctl->tree_lock);
1064 	btrfs_discard_update_discardable(block_group);
1065 	spin_unlock(&ctl->tree_lock);
1066 	iput(inode);
1067 	return ret;
1068 }
1069 
1070 static noinline_for_stack
write_cache_extent_entries(struct btrfs_io_ctl * io_ctl,struct btrfs_free_space_ctl * ctl,struct btrfs_block_group * block_group,int * entries,int * bitmaps,struct list_head * bitmap_list)1071 int write_cache_extent_entries(struct btrfs_io_ctl *io_ctl,
1072 			      struct btrfs_free_space_ctl *ctl,
1073 			      struct btrfs_block_group *block_group,
1074 			      int *entries, int *bitmaps,
1075 			      struct list_head *bitmap_list)
1076 {
1077 	int ret;
1078 	struct btrfs_free_cluster *cluster = NULL;
1079 	struct btrfs_free_cluster *cluster_locked = NULL;
1080 	struct rb_node *node = rb_first(&ctl->free_space_offset);
1081 	struct btrfs_trim_range *trim_entry;
1082 
1083 	/* Get the cluster for this block_group if it exists */
1084 	if (block_group && !list_empty(&block_group->cluster_list)) {
1085 		cluster = list_entry(block_group->cluster_list.next,
1086 				     struct btrfs_free_cluster,
1087 				     block_group_list);
1088 	}
1089 
1090 	if (!node && cluster) {
1091 		cluster_locked = cluster;
1092 		spin_lock(&cluster_locked->lock);
1093 		node = rb_first(&cluster->root);
1094 		cluster = NULL;
1095 	}
1096 
1097 	/* Write out the extent entries */
1098 	while (node) {
1099 		struct btrfs_free_space *e;
1100 
1101 		e = rb_entry(node, struct btrfs_free_space, offset_index);
1102 		*entries += 1;
1103 
1104 		ret = io_ctl_add_entry(io_ctl, e->offset, e->bytes,
1105 				       e->bitmap);
1106 		if (ret)
1107 			goto fail;
1108 
1109 		if (e->bitmap) {
1110 			list_add_tail(&e->list, bitmap_list);
1111 			*bitmaps += 1;
1112 		}
1113 		node = rb_next(node);
1114 		if (!node && cluster) {
1115 			node = rb_first(&cluster->root);
1116 			cluster_locked = cluster;
1117 			spin_lock(&cluster_locked->lock);
1118 			cluster = NULL;
1119 		}
1120 	}
1121 	if (cluster_locked) {
1122 		spin_unlock(&cluster_locked->lock);
1123 		cluster_locked = NULL;
1124 	}
1125 
1126 	/*
1127 	 * Make sure we don't miss any range that was removed from our rbtree
1128 	 * because trimming is running. Otherwise after a umount+mount (or crash
1129 	 * after committing the transaction) we would leak free space and get
1130 	 * an inconsistent free space cache report from fsck.
1131 	 */
1132 	list_for_each_entry(trim_entry, &ctl->trimming_ranges, list) {
1133 		ret = io_ctl_add_entry(io_ctl, trim_entry->start,
1134 				       trim_entry->bytes, NULL);
1135 		if (ret)
1136 			goto fail;
1137 		*entries += 1;
1138 	}
1139 
1140 	return 0;
1141 fail:
1142 	if (cluster_locked)
1143 		spin_unlock(&cluster_locked->lock);
1144 	return -ENOSPC;
1145 }
1146 
1147 static noinline_for_stack int
update_cache_item(struct btrfs_trans_handle * trans,struct btrfs_root * root,struct inode * inode,struct btrfs_path * path,u64 offset,int entries,int bitmaps)1148 update_cache_item(struct btrfs_trans_handle *trans,
1149 		  struct btrfs_root *root,
1150 		  struct inode *inode,
1151 		  struct btrfs_path *path, u64 offset,
1152 		  int entries, int bitmaps)
1153 {
1154 	struct btrfs_key key;
1155 	struct btrfs_free_space_header *header;
1156 	struct extent_buffer *leaf;
1157 	int ret;
1158 
1159 	key.objectid = BTRFS_FREE_SPACE_OBJECTID;
1160 	key.offset = offset;
1161 	key.type = 0;
1162 
1163 	ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
1164 	if (ret < 0) {
1165 		clear_extent_bit(&BTRFS_I(inode)->io_tree, 0, inode->i_size - 1,
1166 				 EXTENT_DELALLOC, NULL);
1167 		goto fail;
1168 	}
1169 	leaf = path->nodes[0];
1170 	if (ret > 0) {
1171 		struct btrfs_key found_key;
1172 		ASSERT(path->slots[0]);
1173 		path->slots[0]--;
1174 		btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
1175 		if (found_key.objectid != BTRFS_FREE_SPACE_OBJECTID ||
1176 		    found_key.offset != offset) {
1177 			clear_extent_bit(&BTRFS_I(inode)->io_tree, 0,
1178 					 inode->i_size - 1, EXTENT_DELALLOC,
1179 					 NULL);
1180 			btrfs_release_path(path);
1181 			goto fail;
1182 		}
1183 	}
1184 
1185 	BTRFS_I(inode)->generation = trans->transid;
1186 	header = btrfs_item_ptr(leaf, path->slots[0],
1187 				struct btrfs_free_space_header);
1188 	btrfs_set_free_space_entries(leaf, header, entries);
1189 	btrfs_set_free_space_bitmaps(leaf, header, bitmaps);
1190 	btrfs_set_free_space_generation(leaf, header, trans->transid);
1191 	btrfs_mark_buffer_dirty(leaf);
1192 	btrfs_release_path(path);
1193 
1194 	return 0;
1195 
1196 fail:
1197 	return -1;
1198 }
1199 
write_pinned_extent_entries(struct btrfs_trans_handle * trans,struct btrfs_block_group * block_group,struct btrfs_io_ctl * io_ctl,int * entries)1200 static noinline_for_stack int write_pinned_extent_entries(
1201 			    struct btrfs_trans_handle *trans,
1202 			    struct btrfs_block_group *block_group,
1203 			    struct btrfs_io_ctl *io_ctl,
1204 			    int *entries)
1205 {
1206 	u64 start, extent_start, extent_end, len;
1207 	struct extent_io_tree *unpin = NULL;
1208 	int ret;
1209 
1210 	if (!block_group)
1211 		return 0;
1212 
1213 	/*
1214 	 * We want to add any pinned extents to our free space cache
1215 	 * so we don't leak the space
1216 	 *
1217 	 * We shouldn't have switched the pinned extents yet so this is the
1218 	 * right one
1219 	 */
1220 	unpin = &trans->transaction->pinned_extents;
1221 
1222 	start = block_group->start;
1223 
1224 	while (start < block_group->start + block_group->length) {
1225 		ret = find_first_extent_bit(unpin, start,
1226 					    &extent_start, &extent_end,
1227 					    EXTENT_DIRTY, NULL);
1228 		if (ret)
1229 			return 0;
1230 
1231 		/* This pinned extent is out of our range */
1232 		if (extent_start >= block_group->start + block_group->length)
1233 			return 0;
1234 
1235 		extent_start = max(extent_start, start);
1236 		extent_end = min(block_group->start + block_group->length,
1237 				 extent_end + 1);
1238 		len = extent_end - extent_start;
1239 
1240 		*entries += 1;
1241 		ret = io_ctl_add_entry(io_ctl, extent_start, len, NULL);
1242 		if (ret)
1243 			return -ENOSPC;
1244 
1245 		start = extent_end;
1246 	}
1247 
1248 	return 0;
1249 }
1250 
1251 static noinline_for_stack int
write_bitmap_entries(struct btrfs_io_ctl * io_ctl,struct list_head * bitmap_list)1252 write_bitmap_entries(struct btrfs_io_ctl *io_ctl, struct list_head *bitmap_list)
1253 {
1254 	struct btrfs_free_space *entry, *next;
1255 	int ret;
1256 
1257 	/* Write out the bitmaps */
1258 	list_for_each_entry_safe(entry, next, bitmap_list, list) {
1259 		ret = io_ctl_add_bitmap(io_ctl, entry->bitmap);
1260 		if (ret)
1261 			return -ENOSPC;
1262 		list_del_init(&entry->list);
1263 	}
1264 
1265 	return 0;
1266 }
1267 
flush_dirty_cache(struct inode * inode)1268 static int flush_dirty_cache(struct inode *inode)
1269 {
1270 	int ret;
1271 
1272 	ret = btrfs_wait_ordered_range(inode, 0, (u64)-1);
1273 	if (ret)
1274 		clear_extent_bit(&BTRFS_I(inode)->io_tree, 0, inode->i_size - 1,
1275 				 EXTENT_DELALLOC, NULL);
1276 
1277 	return ret;
1278 }
1279 
1280 static void noinline_for_stack
cleanup_bitmap_list(struct list_head * bitmap_list)1281 cleanup_bitmap_list(struct list_head *bitmap_list)
1282 {
1283 	struct btrfs_free_space *entry, *next;
1284 
1285 	list_for_each_entry_safe(entry, next, bitmap_list, list)
1286 		list_del_init(&entry->list);
1287 }
1288 
1289 static void noinline_for_stack
cleanup_write_cache_enospc(struct inode * inode,struct btrfs_io_ctl * io_ctl,struct extent_state ** cached_state)1290 cleanup_write_cache_enospc(struct inode *inode,
1291 			   struct btrfs_io_ctl *io_ctl,
1292 			   struct extent_state **cached_state)
1293 {
1294 	io_ctl_drop_pages(io_ctl);
1295 	unlock_extent(&BTRFS_I(inode)->io_tree, 0, i_size_read(inode) - 1,
1296 		      cached_state);
1297 }
1298 
__btrfs_wait_cache_io(struct btrfs_root * root,struct btrfs_trans_handle * trans,struct btrfs_block_group * block_group,struct btrfs_io_ctl * io_ctl,struct btrfs_path * path,u64 offset)1299 static int __btrfs_wait_cache_io(struct btrfs_root *root,
1300 				 struct btrfs_trans_handle *trans,
1301 				 struct btrfs_block_group *block_group,
1302 				 struct btrfs_io_ctl *io_ctl,
1303 				 struct btrfs_path *path, u64 offset)
1304 {
1305 	int ret;
1306 	struct inode *inode = io_ctl->inode;
1307 
1308 	if (!inode)
1309 		return 0;
1310 
1311 	/* Flush the dirty pages in the cache file. */
1312 	ret = flush_dirty_cache(inode);
1313 	if (ret)
1314 		goto out;
1315 
1316 	/* Update the cache item to tell everyone this cache file is valid. */
1317 	ret = update_cache_item(trans, root, inode, path, offset,
1318 				io_ctl->entries, io_ctl->bitmaps);
1319 out:
1320 	if (ret) {
1321 		invalidate_inode_pages2(inode->i_mapping);
1322 		BTRFS_I(inode)->generation = 0;
1323 		if (block_group)
1324 			btrfs_debug(root->fs_info,
1325 	  "failed to write free space cache for block group %llu error %d",
1326 				  block_group->start, ret);
1327 	}
1328 	btrfs_update_inode(trans, root, BTRFS_I(inode));
1329 
1330 	if (block_group) {
1331 		/* the dirty list is protected by the dirty_bgs_lock */
1332 		spin_lock(&trans->transaction->dirty_bgs_lock);
1333 
1334 		/* the disk_cache_state is protected by the block group lock */
1335 		spin_lock(&block_group->lock);
1336 
1337 		/*
1338 		 * only mark this as written if we didn't get put back on
1339 		 * the dirty list while waiting for IO.   Otherwise our
1340 		 * cache state won't be right, and we won't get written again
1341 		 */
1342 		if (!ret && list_empty(&block_group->dirty_list))
1343 			block_group->disk_cache_state = BTRFS_DC_WRITTEN;
1344 		else if (ret)
1345 			block_group->disk_cache_state = BTRFS_DC_ERROR;
1346 
1347 		spin_unlock(&block_group->lock);
1348 		spin_unlock(&trans->transaction->dirty_bgs_lock);
1349 		io_ctl->inode = NULL;
1350 		iput(inode);
1351 	}
1352 
1353 	return ret;
1354 
1355 }
1356 
btrfs_wait_cache_io(struct btrfs_trans_handle * trans,struct btrfs_block_group * block_group,struct btrfs_path * path)1357 int btrfs_wait_cache_io(struct btrfs_trans_handle *trans,
1358 			struct btrfs_block_group *block_group,
1359 			struct btrfs_path *path)
1360 {
1361 	return __btrfs_wait_cache_io(block_group->fs_info->tree_root, trans,
1362 				     block_group, &block_group->io_ctl,
1363 				     path, block_group->start);
1364 }
1365 
1366 /**
1367  * Write out cached info to an inode
1368  *
1369  * @root:        root the inode belongs to
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  */
__btrfs_write_out_cache(struct btrfs_root * root,struct inode * inode,struct btrfs_free_space_ctl * ctl,struct btrfs_block_group * block_group,struct btrfs_io_ctl * io_ctl,struct btrfs_trans_handle * trans)1380 static int __btrfs_write_out_cache(struct btrfs_root *root, 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, 1);
1398 	if (ret)
1399 		return ret;
1400 
1401 	if (block_group && (block_group->flags & BTRFS_BLOCK_GROUP_DATA)) {
1402 		down_write(&block_group->data_rwsem);
1403 		spin_lock(&block_group->lock);
1404 		if (block_group->delalloc_bytes) {
1405 			block_group->disk_cache_state = BTRFS_DC_WRITTEN;
1406 			spin_unlock(&block_group->lock);
1407 			up_write(&block_group->data_rwsem);
1408 			BTRFS_I(inode)->generation = 0;
1409 			ret = 0;
1410 			must_iput = 1;
1411 			goto out;
1412 		}
1413 		spin_unlock(&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, false);
1418 	if (ret)
1419 		goto out_unlock;
1420 
1421 	lock_extent(&BTRFS_I(inode)->io_tree, 0, i_size_read(inode) - 1,
1422 		    &cached_state);
1423 
1424 	io_ctl_set_generation(io_ctl, trans->transid);
1425 
1426 	mutex_lock(&ctl->cache_writeout_mutex);
1427 	/* Write out the extent entries in the free space cache */
1428 	spin_lock(&ctl->tree_lock);
1429 	ret = write_cache_extent_entries(io_ctl, ctl,
1430 					 block_group, &entries, &bitmaps,
1431 					 &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);
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);
1453 	spin_unlock(&ctl->tree_lock);
1454 	mutex_unlock(&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(BTRFS_I(inode), io_ctl->pages,
1463 				io_ctl->num_pages, 0, i_size_read(inode),
1464 				&cached_state, false);
1465 	if (ret)
1466 		goto out_nospc;
1467 
1468 	if (block_group && (block_group->flags & BTRFS_BLOCK_GROUP_DATA))
1469 		up_write(&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(&BTRFS_I(inode)->io_tree, 0, i_size_read(inode) - 1,
1478 		      &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, 0, (u64)-1);
1489 	if (ret)
1490 		goto out;
1491 
1492 	return 0;
1493 
1494 out_nospc_locked:
1495 	cleanup_bitmap_list(&bitmap_list);
1496 	spin_unlock(&ctl->tree_lock);
1497 	mutex_unlock(&ctl->cache_writeout_mutex);
1498 
1499 out_nospc:
1500 	cleanup_write_cache_enospc(inode, io_ctl, &cached_state);
1501 
1502 out_unlock:
1503 	if (block_group && (block_group->flags & BTRFS_BLOCK_GROUP_DATA))
1504 		up_write(&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(inode->i_mapping);
1511 		BTRFS_I(inode)->generation = 0;
1512 	}
1513 	btrfs_update_inode(trans, root, BTRFS_I(inode));
1514 	if (must_iput)
1515 		iput(inode);
1516 	return ret;
1517 }
1518 
btrfs_write_out_cache(struct btrfs_trans_handle * trans,struct btrfs_block_group * block_group,struct btrfs_path * path)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(&block_group->lock);
1529 	if (block_group->disk_cache_state < BTRFS_DC_SETUP) {
1530 		spin_unlock(&block_group->lock);
1531 		return 0;
1532 	}
1533 	spin_unlock(&block_group->lock);
1534 
1535 	inode = lookup_free_space_inode(block_group, path);
1536 	if (IS_ERR(inode))
1537 		return 0;
1538 
1539 	ret = __btrfs_write_out_cache(fs_info->tree_root, inode, ctl,
1540 				block_group, &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(&block_group->lock);
1546 		block_group->disk_cache_state = BTRFS_DC_ERROR;
1547 		spin_unlock(&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 
offset_to_bit(u64 bitmap_start,u32 unit,u64 offset)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(offset, unit));
1567 }
1568 
bytes_to_bits(u64 bytes,u32 unit)1569 static inline unsigned long bytes_to_bits(u64 bytes, u32 unit)
1570 {
1571 	return (unsigned long)(div_u64(bytes, unit));
1572 }
1573 
offset_to_bitmap(struct btrfs_free_space_ctl * ctl,u64 offset)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(bitmap_start, bytes_per_bitmap);
1583 	bitmap_start *= bytes_per_bitmap;
1584 	bitmap_start += ctl->start;
1585 
1586 	return bitmap_start;
1587 }
1588 
tree_insert_offset(struct rb_root * root,u64 offset,struct rb_node * node,int bitmap)1589 static int tree_insert_offset(struct rb_root *root, u64 offset,
1590 			      struct rb_node *node, int bitmap)
1591 {
1592 	struct rb_node **p = &root->rb_node;
1593 	struct rb_node *parent = NULL;
1594 	struct btrfs_free_space *info;
1595 
1596 	while (*p) {
1597 		parent = *p;
1598 		info = rb_entry(parent, struct btrfs_free_space, offset_index);
1599 
1600 		if (offset < info->offset) {
1601 			p = &(*p)->rb_left;
1602 		} else if (offset > info->offset) {
1603 			p = &(*p)->rb_right;
1604 		} else {
1605 			/*
1606 			 * we could have a bitmap entry and an extent entry
1607 			 * share the same offset.  If this is the case, we want
1608 			 * the extent entry to always be found first if we do a
1609 			 * linear search through the tree, since we want to have
1610 			 * the quickest allocation time, and allocating from an
1611 			 * extent is faster than allocating from a bitmap.  So
1612 			 * if we're inserting a bitmap and we find an entry at
1613 			 * this offset, we want to go right, or after this entry
1614 			 * logically.  If we are inserting an extent and we've
1615 			 * found a bitmap, we want to go left, or before
1616 			 * logically.
1617 			 */
1618 			if (bitmap) {
1619 				if (info->bitmap) {
1620 					WARN_ON_ONCE(1);
1621 					return -EEXIST;
1622 				}
1623 				p = &(*p)->rb_right;
1624 			} else {
1625 				if (!info->bitmap) {
1626 					WARN_ON_ONCE(1);
1627 					return -EEXIST;
1628 				}
1629 				p = &(*p)->rb_left;
1630 			}
1631 		}
1632 	}
1633 
1634 	rb_link_node(node, parent, p);
1635 	rb_insert_color(node, root);
1636 
1637 	return 0;
1638 }
1639 
1640 /*
1641  * This is a little subtle.  We *only* have ->max_extent_size set if we actually
1642  * searched through the bitmap and figured out the largest ->max_extent_size,
1643  * otherwise it's 0.  In the case that it's 0 we don't want to tell the
1644  * allocator the wrong thing, we want to use the actual real max_extent_size
1645  * we've found already if it's larger, or we want to use ->bytes.
1646  *
1647  * This matters because find_free_space() will skip entries who's ->bytes is
1648  * less than the required bytes.  So if we didn't search down this bitmap, we
1649  * may pick some previous entry that has a smaller ->max_extent_size than we
1650  * have.  For example, assume we have two entries, one that has
1651  * ->max_extent_size set to 4K and ->bytes set to 1M.  A second entry hasn't set
1652  * ->max_extent_size yet, has ->bytes set to 8K and it's contiguous.  We will
1653  *  call into find_free_space(), and return with max_extent_size == 4K, because
1654  *  that first bitmap entry had ->max_extent_size set, but the second one did
1655  *  not.  If instead we returned 8K we'd come in searching for 8K, and find the
1656  *  8K contiguous range.
1657  *
1658  *  Consider the other case, we have 2 8K chunks in that second entry and still
1659  *  don't have ->max_extent_size set.  We'll return 16K, and the next time the
1660  *  allocator comes in it'll fully search our second bitmap, and this time it'll
1661  *  get an uptodate value of 8K as the maximum chunk size.  Then we'll get the
1662  *  right allocation the next loop through.
1663  */
get_max_extent_size(const struct btrfs_free_space * entry)1664 static inline u64 get_max_extent_size(const struct btrfs_free_space *entry)
1665 {
1666 	if (entry->bitmap && entry->max_extent_size)
1667 		return entry->max_extent_size;
1668 	return entry->bytes;
1669 }
1670 
1671 /*
1672  * We want the largest entry to be leftmost, so this is inverted from what you'd
1673  * normally expect.
1674  */
entry_less(struct rb_node * node,const struct rb_node * parent)1675 static bool entry_less(struct rb_node *node, const struct rb_node *parent)
1676 {
1677 	const struct btrfs_free_space *entry, *exist;
1678 
1679 	entry = rb_entry(node, struct btrfs_free_space, bytes_index);
1680 	exist = rb_entry(parent, struct btrfs_free_space, bytes_index);
1681 	return get_max_extent_size(exist) < get_max_extent_size(entry);
1682 }
1683 
1684 /*
1685  * searches the tree for the given offset.
1686  *
1687  * fuzzy - If this is set, then we are trying to make an allocation, and we just
1688  * want a section that has at least bytes size and comes at or after the given
1689  * offset.
1690  */
1691 static struct btrfs_free_space *
tree_search_offset(struct btrfs_free_space_ctl * ctl,u64 offset,int bitmap_only,int fuzzy)1692 tree_search_offset(struct btrfs_free_space_ctl *ctl,
1693 		   u64 offset, int bitmap_only, int fuzzy)
1694 {
1695 	struct rb_node *n = ctl->free_space_offset.rb_node;
1696 	struct btrfs_free_space *entry = NULL, *prev = NULL;
1697 
1698 	/* find entry that is closest to the 'offset' */
1699 	while (n) {
1700 		entry = rb_entry(n, struct btrfs_free_space, offset_index);
1701 		prev = entry;
1702 
1703 		if (offset < entry->offset)
1704 			n = n->rb_left;
1705 		else if (offset > entry->offset)
1706 			n = n->rb_right;
1707 		else
1708 			break;
1709 
1710 		entry = NULL;
1711 	}
1712 
1713 	if (bitmap_only) {
1714 		if (!entry)
1715 			return NULL;
1716 		if (entry->bitmap)
1717 			return entry;
1718 
1719 		/*
1720 		 * bitmap entry and extent entry may share same offset,
1721 		 * in that case, bitmap entry comes after extent entry.
1722 		 */
1723 		n = rb_next(n);
1724 		if (!n)
1725 			return NULL;
1726 		entry = rb_entry(n, struct btrfs_free_space, offset_index);
1727 		if (entry->offset != offset)
1728 			return NULL;
1729 
1730 		WARN_ON(!entry->bitmap);
1731 		return entry;
1732 	} else if (entry) {
1733 		if (entry->bitmap) {
1734 			/*
1735 			 * if previous extent entry covers the offset,
1736 			 * we should return it instead of the bitmap entry
1737 			 */
1738 			n = rb_prev(&entry->offset_index);
1739 			if (n) {
1740 				prev = rb_entry(n, struct btrfs_free_space,
1741 						offset_index);
1742 				if (!prev->bitmap &&
1743 				    prev->offset + prev->bytes > offset)
1744 					entry = prev;
1745 			}
1746 		}
1747 		return entry;
1748 	}
1749 
1750 	if (!prev)
1751 		return NULL;
1752 
1753 	/* find last entry before the 'offset' */
1754 	entry = prev;
1755 	if (entry->offset > offset) {
1756 		n = rb_prev(&entry->offset_index);
1757 		if (n) {
1758 			entry = rb_entry(n, struct btrfs_free_space,
1759 					offset_index);
1760 			ASSERT(entry->offset <= offset);
1761 		} else {
1762 			if (fuzzy)
1763 				return entry;
1764 			else
1765 				return NULL;
1766 		}
1767 	}
1768 
1769 	if (entry->bitmap) {
1770 		n = rb_prev(&entry->offset_index);
1771 		if (n) {
1772 			prev = rb_entry(n, struct btrfs_free_space,
1773 					offset_index);
1774 			if (!prev->bitmap &&
1775 			    prev->offset + prev->bytes > offset)
1776 				return prev;
1777 		}
1778 		if (entry->offset + BITS_PER_BITMAP * ctl->unit > offset)
1779 			return entry;
1780 	} else if (entry->offset + entry->bytes > offset)
1781 		return entry;
1782 
1783 	if (!fuzzy)
1784 		return NULL;
1785 
1786 	while (1) {
1787 		n = rb_next(&entry->offset_index);
1788 		if (!n)
1789 			return NULL;
1790 		entry = rb_entry(n, struct btrfs_free_space, offset_index);
1791 		if (entry->bitmap) {
1792 			if (entry->offset + BITS_PER_BITMAP *
1793 			    ctl->unit > offset)
1794 				break;
1795 		} else {
1796 			if (entry->offset + entry->bytes > offset)
1797 				break;
1798 		}
1799 	}
1800 	return entry;
1801 }
1802 
unlink_free_space(struct btrfs_free_space_ctl * ctl,struct btrfs_free_space * info,bool update_stat)1803 static inline void unlink_free_space(struct btrfs_free_space_ctl *ctl,
1804 				     struct btrfs_free_space *info,
1805 				     bool update_stat)
1806 {
1807 	rb_erase(&info->offset_index, &ctl->free_space_offset);
1808 	rb_erase_cached(&info->bytes_index, &ctl->free_space_bytes);
1809 	ctl->free_extents--;
1810 
1811 	if (!info->bitmap && !btrfs_free_space_trimmed(info)) {
1812 		ctl->discardable_extents[BTRFS_STAT_CURR]--;
1813 		ctl->discardable_bytes[BTRFS_STAT_CURR] -= info->bytes;
1814 	}
1815 
1816 	if (update_stat)
1817 		ctl->free_space -= info->bytes;
1818 }
1819 
link_free_space(struct btrfs_free_space_ctl * ctl,struct btrfs_free_space * info)1820 static int link_free_space(struct btrfs_free_space_ctl *ctl,
1821 			   struct btrfs_free_space *info)
1822 {
1823 	int ret = 0;
1824 
1825 	ASSERT(info->bytes || info->bitmap);
1826 	ret = tree_insert_offset(&ctl->free_space_offset, info->offset,
1827 				 &info->offset_index, (info->bitmap != NULL));
1828 	if (ret)
1829 		return ret;
1830 
1831 	rb_add_cached(&info->bytes_index, &ctl->free_space_bytes, entry_less);
1832 
1833 	if (!info->bitmap && !btrfs_free_space_trimmed(info)) {
1834 		ctl->discardable_extents[BTRFS_STAT_CURR]++;
1835 		ctl->discardable_bytes[BTRFS_STAT_CURR] += info->bytes;
1836 	}
1837 
1838 	ctl->free_space += info->bytes;
1839 	ctl->free_extents++;
1840 	return ret;
1841 }
1842 
relink_bitmap_entry(struct btrfs_free_space_ctl * ctl,struct btrfs_free_space * info)1843 static void relink_bitmap_entry(struct btrfs_free_space_ctl *ctl,
1844 				struct btrfs_free_space *info)
1845 {
1846 	ASSERT(info->bitmap);
1847 
1848 	/*
1849 	 * If our entry is empty it's because we're on a cluster and we don't
1850 	 * want to re-link it into our ctl bytes index.
1851 	 */
1852 	if (RB_EMPTY_NODE(&info->bytes_index))
1853 		return;
1854 
1855 	rb_erase_cached(&info->bytes_index, &ctl->free_space_bytes);
1856 	rb_add_cached(&info->bytes_index, &ctl->free_space_bytes, entry_less);
1857 }
1858 
bitmap_clear_bits(struct btrfs_free_space_ctl * ctl,struct btrfs_free_space * info,u64 offset,u64 bytes,bool update_stat)1859 static inline void bitmap_clear_bits(struct btrfs_free_space_ctl *ctl,
1860 				     struct btrfs_free_space *info,
1861 				     u64 offset, u64 bytes, bool update_stat)
1862 {
1863 	unsigned long start, count, end;
1864 	int extent_delta = -1;
1865 
1866 	start = offset_to_bit(info->offset, ctl->unit, offset);
1867 	count = bytes_to_bits(bytes, ctl->unit);
1868 	end = start + count;
1869 	ASSERT(end <= BITS_PER_BITMAP);
1870 
1871 	bitmap_clear(info->bitmap, start, count);
1872 
1873 	info->bytes -= bytes;
1874 	if (info->max_extent_size > ctl->unit)
1875 		info->max_extent_size = 0;
1876 
1877 	relink_bitmap_entry(ctl, info);
1878 
1879 	if (start && test_bit(start - 1, info->bitmap))
1880 		extent_delta++;
1881 
1882 	if (end < BITS_PER_BITMAP && test_bit(end, info->bitmap))
1883 		extent_delta++;
1884 
1885 	info->bitmap_extents += extent_delta;
1886 	if (!btrfs_free_space_trimmed(info)) {
1887 		ctl->discardable_extents[BTRFS_STAT_CURR] += extent_delta;
1888 		ctl->discardable_bytes[BTRFS_STAT_CURR] -= bytes;
1889 	}
1890 
1891 	if (update_stat)
1892 		ctl->free_space -= bytes;
1893 }
1894 
bitmap_set_bits(struct btrfs_free_space_ctl * ctl,struct btrfs_free_space * info,u64 offset,u64 bytes)1895 static void bitmap_set_bits(struct btrfs_free_space_ctl *ctl,
1896 			    struct btrfs_free_space *info, u64 offset,
1897 			    u64 bytes)
1898 {
1899 	unsigned long start, count, end;
1900 	int extent_delta = 1;
1901 
1902 	start = offset_to_bit(info->offset, ctl->unit, offset);
1903 	count = bytes_to_bits(bytes, ctl->unit);
1904 	end = start + count;
1905 	ASSERT(end <= BITS_PER_BITMAP);
1906 
1907 	bitmap_set(info->bitmap, start, count);
1908 
1909 	/*
1910 	 * We set some bytes, we have no idea what the max extent size is
1911 	 * anymore.
1912 	 */
1913 	info->max_extent_size = 0;
1914 	info->bytes += bytes;
1915 	ctl->free_space += bytes;
1916 
1917 	relink_bitmap_entry(ctl, info);
1918 
1919 	if (start && test_bit(start - 1, info->bitmap))
1920 		extent_delta--;
1921 
1922 	if (end < BITS_PER_BITMAP && test_bit(end, info->bitmap))
1923 		extent_delta--;
1924 
1925 	info->bitmap_extents += extent_delta;
1926 	if (!btrfs_free_space_trimmed(info)) {
1927 		ctl->discardable_extents[BTRFS_STAT_CURR] += extent_delta;
1928 		ctl->discardable_bytes[BTRFS_STAT_CURR] += bytes;
1929 	}
1930 }
1931 
1932 /*
1933  * If we can not find suitable extent, we will use bytes to record
1934  * the size of the max extent.
1935  */
search_bitmap(struct btrfs_free_space_ctl * ctl,struct btrfs_free_space * bitmap_info,u64 * offset,u64 * bytes,bool for_alloc)1936 static int search_bitmap(struct btrfs_free_space_ctl *ctl,
1937 			 struct btrfs_free_space *bitmap_info, u64 *offset,
1938 			 u64 *bytes, bool for_alloc)
1939 {
1940 	unsigned long found_bits = 0;
1941 	unsigned long max_bits = 0;
1942 	unsigned long bits, i;
1943 	unsigned long next_zero;
1944 	unsigned long extent_bits;
1945 
1946 	/*
1947 	 * Skip searching the bitmap if we don't have a contiguous section that
1948 	 * is large enough for this allocation.
1949 	 */
1950 	if (for_alloc &&
1951 	    bitmap_info->max_extent_size &&
1952 	    bitmap_info->max_extent_size < *bytes) {
1953 		*bytes = bitmap_info->max_extent_size;
1954 		return -1;
1955 	}
1956 
1957 	i = offset_to_bit(bitmap_info->offset, ctl->unit,
1958 			  max_t(u64, *offset, bitmap_info->offset));
1959 	bits = bytes_to_bits(*bytes, ctl->unit);
1960 
1961 	for_each_set_bit_from(i, bitmap_info->bitmap, BITS_PER_BITMAP) {
1962 		if (for_alloc && bits == 1) {
1963 			found_bits = 1;
1964 			break;
1965 		}
1966 		next_zero = find_next_zero_bit(bitmap_info->bitmap,
1967 					       BITS_PER_BITMAP, i);
1968 		extent_bits = next_zero - i;
1969 		if (extent_bits >= bits) {
1970 			found_bits = extent_bits;
1971 			break;
1972 		} else if (extent_bits > max_bits) {
1973 			max_bits = extent_bits;
1974 		}
1975 		i = next_zero;
1976 	}
1977 
1978 	if (found_bits) {
1979 		*offset = (u64)(i * ctl->unit) + bitmap_info->offset;
1980 		*bytes = (u64)(found_bits) * ctl->unit;
1981 		return 0;
1982 	}
1983 
1984 	*bytes = (u64)(max_bits) * ctl->unit;
1985 	bitmap_info->max_extent_size = *bytes;
1986 	relink_bitmap_entry(ctl, bitmap_info);
1987 	return -1;
1988 }
1989 
1990 /* Cache the size of the max extent in bytes */
1991 static struct btrfs_free_space *
find_free_space(struct btrfs_free_space_ctl * ctl,u64 * offset,u64 * bytes,unsigned long align,u64 * max_extent_size,bool use_bytes_index)1992 find_free_space(struct btrfs_free_space_ctl *ctl, u64 *offset, u64 *bytes,
1993 		unsigned long align, u64 *max_extent_size, bool use_bytes_index)
1994 {
1995 	struct btrfs_free_space *entry;
1996 	struct rb_node *node;
1997 	u64 tmp;
1998 	u64 align_off;
1999 	int ret;
2000 
2001 	if (!ctl->free_space_offset.rb_node)
2002 		goto out;
2003 again:
2004 	if (use_bytes_index) {
2005 		node = rb_first_cached(&ctl->free_space_bytes);
2006 	} else {
2007 		entry = tree_search_offset(ctl, offset_to_bitmap(ctl, *offset),
2008 					   0, 1);
2009 		if (!entry)
2010 			goto out;
2011 		node = &entry->offset_index;
2012 	}
2013 
2014 	for (; node; node = rb_next(node)) {
2015 		if (use_bytes_index)
2016 			entry = rb_entry(node, struct btrfs_free_space,
2017 					 bytes_index);
2018 		else
2019 			entry = rb_entry(node, struct btrfs_free_space,
2020 					 offset_index);
2021 
2022 		/*
2023 		 * If we are using the bytes index then all subsequent entries
2024 		 * in this tree are going to be < bytes, so simply set the max
2025 		 * extent size and exit the loop.
2026 		 *
2027 		 * If we're using the offset index then we need to keep going
2028 		 * through the rest of the tree.
2029 		 */
2030 		if (entry->bytes < *bytes) {
2031 			*max_extent_size = max(get_max_extent_size(entry),
2032 					       *max_extent_size);
2033 			if (use_bytes_index)
2034 				break;
2035 			continue;
2036 		}
2037 
2038 		/* make sure the space returned is big enough
2039 		 * to match our requested alignment
2040 		 */
2041 		if (*bytes >= align) {
2042 			tmp = entry->offset - ctl->start + align - 1;
2043 			tmp = div64_u64(tmp, align);
2044 			tmp = tmp * align + ctl->start;
2045 			align_off = tmp - entry->offset;
2046 		} else {
2047 			align_off = 0;
2048 			tmp = entry->offset;
2049 		}
2050 
2051 		/*
2052 		 * We don't break here if we're using the bytes index because we
2053 		 * may have another entry that has the correct alignment that is
2054 		 * the right size, so we don't want to miss that possibility.
2055 		 * At worst this adds another loop through the logic, but if we
2056 		 * broke here we could prematurely ENOSPC.
2057 		 */
2058 		if (entry->bytes < *bytes + align_off) {
2059 			*max_extent_size = max(get_max_extent_size(entry),
2060 					       *max_extent_size);
2061 			continue;
2062 		}
2063 
2064 		if (entry->bitmap) {
2065 			struct rb_node *old_next = rb_next(node);
2066 			u64 size = *bytes;
2067 
2068 			ret = search_bitmap(ctl, entry, &tmp, &size, true);
2069 			if (!ret) {
2070 				*offset = tmp;
2071 				*bytes = size;
2072 				return entry;
2073 			} else {
2074 				*max_extent_size =
2075 					max(get_max_extent_size(entry),
2076 					    *max_extent_size);
2077 			}
2078 
2079 			/*
2080 			 * The bitmap may have gotten re-arranged in the space
2081 			 * index here because the max_extent_size may have been
2082 			 * updated.  Start from the beginning again if this
2083 			 * happened.
2084 			 */
2085 			if (use_bytes_index && old_next != rb_next(node))
2086 				goto again;
2087 			continue;
2088 		}
2089 
2090 		*offset = tmp;
2091 		*bytes = entry->bytes - align_off;
2092 		return entry;
2093 	}
2094 out:
2095 	return NULL;
2096 }
2097 
add_new_bitmap(struct btrfs_free_space_ctl * ctl,struct btrfs_free_space * info,u64 offset)2098 static void add_new_bitmap(struct btrfs_free_space_ctl *ctl,
2099 			   struct btrfs_free_space *info, u64 offset)
2100 {
2101 	info->offset = offset_to_bitmap(ctl, offset);
2102 	info->bytes = 0;
2103 	info->bitmap_extents = 0;
2104 	INIT_LIST_HEAD(&info->list);
2105 	link_free_space(ctl, info);
2106 	ctl->total_bitmaps++;
2107 	recalculate_thresholds(ctl);
2108 }
2109 
free_bitmap(struct btrfs_free_space_ctl * ctl,struct btrfs_free_space * bitmap_info)2110 static void free_bitmap(struct btrfs_free_space_ctl *ctl,
2111 			struct btrfs_free_space *bitmap_info)
2112 {
2113 	/*
2114 	 * Normally when this is called, the bitmap is completely empty. However,
2115 	 * if we are blowing up the free space cache for one reason or another
2116 	 * via __btrfs_remove_free_space_cache(), then it may not be freed and
2117 	 * we may leave stats on the table.
2118 	 */
2119 	if (bitmap_info->bytes && !btrfs_free_space_trimmed(bitmap_info)) {
2120 		ctl->discardable_extents[BTRFS_STAT_CURR] -=
2121 			bitmap_info->bitmap_extents;
2122 		ctl->discardable_bytes[BTRFS_STAT_CURR] -= bitmap_info->bytes;
2123 
2124 	}
2125 	unlink_free_space(ctl, bitmap_info, true);
2126 	kmem_cache_free(btrfs_free_space_bitmap_cachep, bitmap_info->bitmap);
2127 	kmem_cache_free(btrfs_free_space_cachep, bitmap_info);
2128 	ctl->total_bitmaps--;
2129 	recalculate_thresholds(ctl);
2130 }
2131 
remove_from_bitmap(struct btrfs_free_space_ctl * ctl,struct btrfs_free_space * bitmap_info,u64 * offset,u64 * bytes)2132 static noinline int remove_from_bitmap(struct btrfs_free_space_ctl *ctl,
2133 			      struct btrfs_free_space *bitmap_info,
2134 			      u64 *offset, u64 *bytes)
2135 {
2136 	u64 end;
2137 	u64 search_start, search_bytes;
2138 	int ret;
2139 
2140 again:
2141 	end = bitmap_info->offset + (u64)(BITS_PER_BITMAP * ctl->unit) - 1;
2142 
2143 	/*
2144 	 * We need to search for bits in this bitmap.  We could only cover some
2145 	 * of the extent in this bitmap thanks to how we add space, so we need
2146 	 * to search for as much as it as we can and clear that amount, and then
2147 	 * go searching for the next bit.
2148 	 */
2149 	search_start = *offset;
2150 	search_bytes = ctl->unit;
2151 	search_bytes = min(search_bytes, end - search_start + 1);
2152 	ret = search_bitmap(ctl, bitmap_info, &search_start, &search_bytes,
2153 			    false);
2154 	if (ret < 0 || search_start != *offset)
2155 		return -EINVAL;
2156 
2157 	/* We may have found more bits than what we need */
2158 	search_bytes = min(search_bytes, *bytes);
2159 
2160 	/* Cannot clear past the end of the bitmap */
2161 	search_bytes = min(search_bytes, end - search_start + 1);
2162 
2163 	bitmap_clear_bits(ctl, bitmap_info, search_start, search_bytes, true);
2164 	*offset += search_bytes;
2165 	*bytes -= search_bytes;
2166 
2167 	if (*bytes) {
2168 		struct rb_node *next = rb_next(&bitmap_info->offset_index);
2169 		if (!bitmap_info->bytes)
2170 			free_bitmap(ctl, bitmap_info);
2171 
2172 		/*
2173 		 * no entry after this bitmap, but we still have bytes to
2174 		 * remove, so something has gone wrong.
2175 		 */
2176 		if (!next)
2177 			return -EINVAL;
2178 
2179 		bitmap_info = rb_entry(next, struct btrfs_free_space,
2180 				       offset_index);
2181 
2182 		/*
2183 		 * if the next entry isn't a bitmap we need to return to let the
2184 		 * extent stuff do its work.
2185 		 */
2186 		if (!bitmap_info->bitmap)
2187 			return -EAGAIN;
2188 
2189 		/*
2190 		 * Ok the next item is a bitmap, but it may not actually hold
2191 		 * the information for the rest of this free space stuff, so
2192 		 * look for it, and if we don't find it return so we can try
2193 		 * everything over again.
2194 		 */
2195 		search_start = *offset;
2196 		search_bytes = ctl->unit;
2197 		ret = search_bitmap(ctl, bitmap_info, &search_start,
2198 				    &search_bytes, false);
2199 		if (ret < 0 || search_start != *offset)
2200 			return -EAGAIN;
2201 
2202 		goto again;
2203 	} else if (!bitmap_info->bytes)
2204 		free_bitmap(ctl, bitmap_info);
2205 
2206 	return 0;
2207 }
2208 
add_bytes_to_bitmap(struct btrfs_free_space_ctl * ctl,struct btrfs_free_space * info,u64 offset,u64 bytes,enum btrfs_trim_state trim_state)2209 static u64 add_bytes_to_bitmap(struct btrfs_free_space_ctl *ctl,
2210 			       struct btrfs_free_space *info, u64 offset,
2211 			       u64 bytes, enum btrfs_trim_state trim_state)
2212 {
2213 	u64 bytes_to_set = 0;
2214 	u64 end;
2215 
2216 	/*
2217 	 * This is a tradeoff to make bitmap trim state minimal.  We mark the
2218 	 * whole bitmap untrimmed if at any point we add untrimmed regions.
2219 	 */
2220 	if (trim_state == BTRFS_TRIM_STATE_UNTRIMMED) {
2221 		if (btrfs_free_space_trimmed(info)) {
2222 			ctl->discardable_extents[BTRFS_STAT_CURR] +=
2223 				info->bitmap_extents;
2224 			ctl->discardable_bytes[BTRFS_STAT_CURR] += info->bytes;
2225 		}
2226 		info->trim_state = BTRFS_TRIM_STATE_UNTRIMMED;
2227 	}
2228 
2229 	end = info->offset + (u64)(BITS_PER_BITMAP * ctl->unit);
2230 
2231 	bytes_to_set = min(end - offset, bytes);
2232 
2233 	bitmap_set_bits(ctl, info, offset, bytes_to_set);
2234 
2235 	return bytes_to_set;
2236 
2237 }
2238 
use_bitmap(struct btrfs_free_space_ctl * ctl,struct btrfs_free_space * info)2239 static bool use_bitmap(struct btrfs_free_space_ctl *ctl,
2240 		      struct btrfs_free_space *info)
2241 {
2242 	struct btrfs_block_group *block_group = ctl->block_group;
2243 	struct btrfs_fs_info *fs_info = block_group->fs_info;
2244 	bool forced = false;
2245 
2246 #ifdef CONFIG_BTRFS_DEBUG
2247 	if (btrfs_should_fragment_free_space(block_group))
2248 		forced = true;
2249 #endif
2250 
2251 	/* This is a way to reclaim large regions from the bitmaps. */
2252 	if (!forced && info->bytes >= FORCE_EXTENT_THRESHOLD)
2253 		return false;
2254 
2255 	/*
2256 	 * If we are below the extents threshold then we can add this as an
2257 	 * extent, and don't have to deal with the bitmap
2258 	 */
2259 	if (!forced && ctl->free_extents < ctl->extents_thresh) {
2260 		/*
2261 		 * If this block group has some small extents we don't want to
2262 		 * use up all of our free slots in the cache with them, we want
2263 		 * to reserve them to larger extents, however if we have plenty
2264 		 * of cache left then go ahead an dadd them, no sense in adding
2265 		 * the overhead of a bitmap if we don't have to.
2266 		 */
2267 		if (info->bytes <= fs_info->sectorsize * 8) {
2268 			if (ctl->free_extents * 3 <= ctl->extents_thresh)
2269 				return false;
2270 		} else {
2271 			return false;
2272 		}
2273 	}
2274 
2275 	/*
2276 	 * The original block groups from mkfs can be really small, like 8
2277 	 * megabytes, so don't bother with a bitmap for those entries.  However
2278 	 * some block groups can be smaller than what a bitmap would cover but
2279 	 * are still large enough that they could overflow the 32k memory limit,
2280 	 * so allow those block groups to still be allowed to have a bitmap
2281 	 * entry.
2282 	 */
2283 	if (((BITS_PER_BITMAP * ctl->unit) >> 1) > block_group->length)
2284 		return false;
2285 
2286 	return true;
2287 }
2288 
2289 static const struct btrfs_free_space_op free_space_op = {
2290 	.use_bitmap		= use_bitmap,
2291 };
2292 
insert_into_bitmap(struct btrfs_free_space_ctl * ctl,struct btrfs_free_space * info)2293 static int insert_into_bitmap(struct btrfs_free_space_ctl *ctl,
2294 			      struct btrfs_free_space *info)
2295 {
2296 	struct btrfs_free_space *bitmap_info;
2297 	struct btrfs_block_group *block_group = NULL;
2298 	int added = 0;
2299 	u64 bytes, offset, bytes_added;
2300 	enum btrfs_trim_state trim_state;
2301 	int ret;
2302 
2303 	bytes = info->bytes;
2304 	offset = info->offset;
2305 	trim_state = info->trim_state;
2306 
2307 	if (!ctl->op->use_bitmap(ctl, info))
2308 		return 0;
2309 
2310 	if (ctl->op == &free_space_op)
2311 		block_group = ctl->block_group;
2312 again:
2313 	/*
2314 	 * Since we link bitmaps right into the cluster we need to see if we
2315 	 * have a cluster here, and if so and it has our bitmap we need to add
2316 	 * the free space to that bitmap.
2317 	 */
2318 	if (block_group && !list_empty(&block_group->cluster_list)) {
2319 		struct btrfs_free_cluster *cluster;
2320 		struct rb_node *node;
2321 		struct btrfs_free_space *entry;
2322 
2323 		cluster = list_entry(block_group->cluster_list.next,
2324 				     struct btrfs_free_cluster,
2325 				     block_group_list);
2326 		spin_lock(&cluster->lock);
2327 		node = rb_first(&cluster->root);
2328 		if (!node) {
2329 			spin_unlock(&cluster->lock);
2330 			goto no_cluster_bitmap;
2331 		}
2332 
2333 		entry = rb_entry(node, struct btrfs_free_space, offset_index);
2334 		if (!entry->bitmap) {
2335 			spin_unlock(&cluster->lock);
2336 			goto no_cluster_bitmap;
2337 		}
2338 
2339 		if (entry->offset == offset_to_bitmap(ctl, offset)) {
2340 			bytes_added = add_bytes_to_bitmap(ctl, entry, offset,
2341 							  bytes, trim_state);
2342 			bytes -= bytes_added;
2343 			offset += bytes_added;
2344 		}
2345 		spin_unlock(&cluster->lock);
2346 		if (!bytes) {
2347 			ret = 1;
2348 			goto out;
2349 		}
2350 	}
2351 
2352 no_cluster_bitmap:
2353 	bitmap_info = tree_search_offset(ctl, offset_to_bitmap(ctl, offset),
2354 					 1, 0);
2355 	if (!bitmap_info) {
2356 		ASSERT(added == 0);
2357 		goto new_bitmap;
2358 	}
2359 
2360 	bytes_added = add_bytes_to_bitmap(ctl, bitmap_info, offset, bytes,
2361 					  trim_state);
2362 	bytes -= bytes_added;
2363 	offset += bytes_added;
2364 	added = 0;
2365 
2366 	if (!bytes) {
2367 		ret = 1;
2368 		goto out;
2369 	} else
2370 		goto again;
2371 
2372 new_bitmap:
2373 	if (info && info->bitmap) {
2374 		add_new_bitmap(ctl, info, offset);
2375 		added = 1;
2376 		info = NULL;
2377 		goto again;
2378 	} else {
2379 		spin_unlock(&ctl->tree_lock);
2380 
2381 		/* no pre-allocated info, allocate a new one */
2382 		if (!info) {
2383 			info = kmem_cache_zalloc(btrfs_free_space_cachep,
2384 						 GFP_NOFS);
2385 			if (!info) {
2386 				spin_lock(&ctl->tree_lock);
2387 				ret = -ENOMEM;
2388 				goto out;
2389 			}
2390 		}
2391 
2392 		/* allocate the bitmap */
2393 		info->bitmap = kmem_cache_zalloc(btrfs_free_space_bitmap_cachep,
2394 						 GFP_NOFS);
2395 		info->trim_state = BTRFS_TRIM_STATE_TRIMMED;
2396 		spin_lock(&ctl->tree_lock);
2397 		if (!info->bitmap) {
2398 			ret = -ENOMEM;
2399 			goto out;
2400 		}
2401 		goto again;
2402 	}
2403 
2404 out:
2405 	if (info) {
2406 		if (info->bitmap)
2407 			kmem_cache_free(btrfs_free_space_bitmap_cachep,
2408 					info->bitmap);
2409 		kmem_cache_free(btrfs_free_space_cachep, info);
2410 	}
2411 
2412 	return ret;
2413 }
2414 
2415 /*
2416  * Free space merging rules:
2417  *  1) Merge trimmed areas together
2418  *  2) Let untrimmed areas coalesce with trimmed areas
2419  *  3) Always pull neighboring regions from bitmaps
2420  *
2421  * The above rules are for when we merge free space based on btrfs_trim_state.
2422  * Rules 2 and 3 are subtle because they are suboptimal, but are done for the
2423  * same reason: to promote larger extent regions which makes life easier for
2424  * find_free_extent().  Rule 2 enables coalescing based on the common path
2425  * being returning free space from btrfs_finish_extent_commit().  So when free
2426  * space is trimmed, it will prevent aggregating trimmed new region and
2427  * untrimmed regions in the rb_tree.  Rule 3 is purely to obtain larger extents
2428  * and provide find_free_extent() with the largest extents possible hoping for
2429  * the reuse path.
2430  */
try_merge_free_space(struct btrfs_free_space_ctl * ctl,struct btrfs_free_space * info,bool update_stat)2431 static bool try_merge_free_space(struct btrfs_free_space_ctl *ctl,
2432 			  struct btrfs_free_space *info, bool update_stat)
2433 {
2434 	struct btrfs_free_space *left_info = NULL;
2435 	struct btrfs_free_space *right_info;
2436 	bool merged = false;
2437 	u64 offset = info->offset;
2438 	u64 bytes = info->bytes;
2439 	const bool is_trimmed = btrfs_free_space_trimmed(info);
2440 
2441 	/*
2442 	 * first we want to see if there is free space adjacent to the range we
2443 	 * are adding, if there is remove that struct and add a new one to
2444 	 * cover the entire range
2445 	 */
2446 	right_info = tree_search_offset(ctl, offset + bytes, 0, 0);
2447 	if (right_info && rb_prev(&right_info->offset_index))
2448 		left_info = rb_entry(rb_prev(&right_info->offset_index),
2449 				     struct btrfs_free_space, offset_index);
2450 	else if (!right_info)
2451 		left_info = tree_search_offset(ctl, offset - 1, 0, 0);
2452 
2453 	/* See try_merge_free_space() comment. */
2454 	if (right_info && !right_info->bitmap &&
2455 	    (!is_trimmed || btrfs_free_space_trimmed(right_info))) {
2456 		unlink_free_space(ctl, right_info, update_stat);
2457 		info->bytes += right_info->bytes;
2458 		kmem_cache_free(btrfs_free_space_cachep, right_info);
2459 		merged = true;
2460 	}
2461 
2462 	/* See try_merge_free_space() comment. */
2463 	if (left_info && !left_info->bitmap &&
2464 	    left_info->offset + left_info->bytes == offset &&
2465 	    (!is_trimmed || btrfs_free_space_trimmed(left_info))) {
2466 		unlink_free_space(ctl, left_info, update_stat);
2467 		info->offset = left_info->offset;
2468 		info->bytes += left_info->bytes;
2469 		kmem_cache_free(btrfs_free_space_cachep, left_info);
2470 		merged = true;
2471 	}
2472 
2473 	return merged;
2474 }
2475 
steal_from_bitmap_to_end(struct btrfs_free_space_ctl * ctl,struct btrfs_free_space * info,bool update_stat)2476 static bool steal_from_bitmap_to_end(struct btrfs_free_space_ctl *ctl,
2477 				     struct btrfs_free_space *info,
2478 				     bool update_stat)
2479 {
2480 	struct btrfs_free_space *bitmap;
2481 	unsigned long i;
2482 	unsigned long j;
2483 	const u64 end = info->offset + info->bytes;
2484 	const u64 bitmap_offset = offset_to_bitmap(ctl, end);
2485 	u64 bytes;
2486 
2487 	bitmap = tree_search_offset(ctl, bitmap_offset, 1, 0);
2488 	if (!bitmap)
2489 		return false;
2490 
2491 	i = offset_to_bit(bitmap->offset, ctl->unit, end);
2492 	j = find_next_zero_bit(bitmap->bitmap, BITS_PER_BITMAP, i);
2493 	if (j == i)
2494 		return false;
2495 	bytes = (j - i) * ctl->unit;
2496 	info->bytes += bytes;
2497 
2498 	/* See try_merge_free_space() comment. */
2499 	if (!btrfs_free_space_trimmed(bitmap))
2500 		info->trim_state = BTRFS_TRIM_STATE_UNTRIMMED;
2501 
2502 	bitmap_clear_bits(ctl, bitmap, end, bytes, update_stat);
2503 
2504 	if (!bitmap->bytes)
2505 		free_bitmap(ctl, bitmap);
2506 
2507 	return true;
2508 }
2509 
steal_from_bitmap_to_front(struct btrfs_free_space_ctl * ctl,struct btrfs_free_space * info,bool update_stat)2510 static bool steal_from_bitmap_to_front(struct btrfs_free_space_ctl *ctl,
2511 				       struct btrfs_free_space *info,
2512 				       bool update_stat)
2513 {
2514 	struct btrfs_free_space *bitmap;
2515 	u64 bitmap_offset;
2516 	unsigned long i;
2517 	unsigned long j;
2518 	unsigned long prev_j;
2519 	u64 bytes;
2520 
2521 	bitmap_offset = offset_to_bitmap(ctl, info->offset);
2522 	/* If we're on a boundary, try the previous logical bitmap. */
2523 	if (bitmap_offset == info->offset) {
2524 		if (info->offset == 0)
2525 			return false;
2526 		bitmap_offset = offset_to_bitmap(ctl, info->offset - 1);
2527 	}
2528 
2529 	bitmap = tree_search_offset(ctl, bitmap_offset, 1, 0);
2530 	if (!bitmap)
2531 		return false;
2532 
2533 	i = offset_to_bit(bitmap->offset, ctl->unit, info->offset) - 1;
2534 	j = 0;
2535 	prev_j = (unsigned long)-1;
2536 	for_each_clear_bit_from(j, bitmap->bitmap, BITS_PER_BITMAP) {
2537 		if (j > i)
2538 			break;
2539 		prev_j = j;
2540 	}
2541 	if (prev_j == i)
2542 		return false;
2543 
2544 	if (prev_j == (unsigned long)-1)
2545 		bytes = (i + 1) * ctl->unit;
2546 	else
2547 		bytes = (i - prev_j) * ctl->unit;
2548 
2549 	info->offset -= bytes;
2550 	info->bytes += bytes;
2551 
2552 	/* See try_merge_free_space() comment. */
2553 	if (!btrfs_free_space_trimmed(bitmap))
2554 		info->trim_state = BTRFS_TRIM_STATE_UNTRIMMED;
2555 
2556 	bitmap_clear_bits(ctl, bitmap, info->offset, bytes, update_stat);
2557 
2558 	if (!bitmap->bytes)
2559 		free_bitmap(ctl, bitmap);
2560 
2561 	return true;
2562 }
2563 
2564 /*
2565  * We prefer always to allocate from extent entries, both for clustered and
2566  * non-clustered allocation requests. So when attempting to add a new extent
2567  * entry, try to see if there's adjacent free space in bitmap entries, and if
2568  * there is, migrate that space from the bitmaps to the extent.
2569  * Like this we get better chances of satisfying space allocation requests
2570  * because we attempt to satisfy them based on a single cache entry, and never
2571  * on 2 or more entries - even if the entries represent a contiguous free space
2572  * region (e.g. 1 extent entry + 1 bitmap entry starting where the extent entry
2573  * ends).
2574  */
steal_from_bitmap(struct btrfs_free_space_ctl * ctl,struct btrfs_free_space * info,bool update_stat)2575 static void steal_from_bitmap(struct btrfs_free_space_ctl *ctl,
2576 			      struct btrfs_free_space *info,
2577 			      bool update_stat)
2578 {
2579 	/*
2580 	 * Only work with disconnected entries, as we can change their offset,
2581 	 * and must be extent entries.
2582 	 */
2583 	ASSERT(!info->bitmap);
2584 	ASSERT(RB_EMPTY_NODE(&info->offset_index));
2585 
2586 	if (ctl->total_bitmaps > 0) {
2587 		bool stole_end;
2588 		bool stole_front = false;
2589 
2590 		stole_end = steal_from_bitmap_to_end(ctl, info, update_stat);
2591 		if (ctl->total_bitmaps > 0)
2592 			stole_front = steal_from_bitmap_to_front(ctl, info,
2593 								 update_stat);
2594 
2595 		if (stole_end || stole_front)
2596 			try_merge_free_space(ctl, info, update_stat);
2597 	}
2598 }
2599 
__btrfs_add_free_space(struct btrfs_block_group * block_group,u64 offset,u64 bytes,enum btrfs_trim_state trim_state)2600 int __btrfs_add_free_space(struct btrfs_block_group *block_group,
2601 			   u64 offset, u64 bytes,
2602 			   enum btrfs_trim_state trim_state)
2603 {
2604 	struct btrfs_fs_info *fs_info = block_group->fs_info;
2605 	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2606 	struct btrfs_free_space *info;
2607 	int ret = 0;
2608 	u64 filter_bytes = bytes;
2609 
2610 	ASSERT(!btrfs_is_zoned(fs_info));
2611 
2612 	info = kmem_cache_zalloc(btrfs_free_space_cachep, GFP_NOFS);
2613 	if (!info)
2614 		return -ENOMEM;
2615 
2616 	info->offset = offset;
2617 	info->bytes = bytes;
2618 	info->trim_state = trim_state;
2619 	RB_CLEAR_NODE(&info->offset_index);
2620 	RB_CLEAR_NODE(&info->bytes_index);
2621 
2622 	spin_lock(&ctl->tree_lock);
2623 
2624 	if (try_merge_free_space(ctl, info, true))
2625 		goto link;
2626 
2627 	/*
2628 	 * There was no extent directly to the left or right of this new
2629 	 * extent then we know we're going to have to allocate a new extent, so
2630 	 * before we do that see if we need to drop this into a bitmap
2631 	 */
2632 	ret = insert_into_bitmap(ctl, info);
2633 	if (ret < 0) {
2634 		goto out;
2635 	} else if (ret) {
2636 		ret = 0;
2637 		goto out;
2638 	}
2639 link:
2640 	/*
2641 	 * Only steal free space from adjacent bitmaps if we're sure we're not
2642 	 * going to add the new free space to existing bitmap entries - because
2643 	 * that would mean unnecessary work that would be reverted. Therefore
2644 	 * attempt to steal space from bitmaps if we're adding an extent entry.
2645 	 */
2646 	steal_from_bitmap(ctl, info, true);
2647 
2648 	filter_bytes = max(filter_bytes, info->bytes);
2649 
2650 	ret = link_free_space(ctl, info);
2651 	if (ret)
2652 		kmem_cache_free(btrfs_free_space_cachep, info);
2653 out:
2654 	btrfs_discard_update_discardable(block_group);
2655 	spin_unlock(&ctl->tree_lock);
2656 
2657 	if (ret) {
2658 		btrfs_crit(fs_info, "unable to add free space :%d", ret);
2659 		ASSERT(ret != -EEXIST);
2660 	}
2661 
2662 	if (trim_state != BTRFS_TRIM_STATE_TRIMMED) {
2663 		btrfs_discard_check_filter(block_group, filter_bytes);
2664 		btrfs_discard_queue_work(&fs_info->discard_ctl, block_group);
2665 	}
2666 
2667 	return ret;
2668 }
2669 
__btrfs_add_free_space_zoned(struct btrfs_block_group * block_group,u64 bytenr,u64 size,bool used)2670 static int __btrfs_add_free_space_zoned(struct btrfs_block_group *block_group,
2671 					u64 bytenr, u64 size, bool used)
2672 {
2673 	struct btrfs_space_info *sinfo = block_group->space_info;
2674 	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2675 	u64 offset = bytenr - block_group->start;
2676 	u64 to_free, to_unusable;
2677 	int bg_reclaim_threshold = 0;
2678 	bool initial = (size == block_group->length);
2679 	u64 reclaimable_unusable;
2680 
2681 	WARN_ON(!initial && offset + size > block_group->zone_capacity);
2682 
2683 	if (!initial)
2684 		bg_reclaim_threshold = READ_ONCE(sinfo->bg_reclaim_threshold);
2685 
2686 	spin_lock(&ctl->tree_lock);
2687 	if (!used)
2688 		to_free = size;
2689 	else if (initial)
2690 		to_free = block_group->zone_capacity;
2691 	else if (offset >= block_group->alloc_offset)
2692 		to_free = size;
2693 	else if (offset + size <= block_group->alloc_offset)
2694 		to_free = 0;
2695 	else
2696 		to_free = offset + size - block_group->alloc_offset;
2697 	to_unusable = size - to_free;
2698 
2699 	ctl->free_space += to_free;
2700 	/*
2701 	 * If the block group is read-only, we should account freed space into
2702 	 * bytes_readonly.
2703 	 */
2704 	if (!block_group->ro)
2705 		block_group->zone_unusable += to_unusable;
2706 	spin_unlock(&ctl->tree_lock);
2707 	if (!used) {
2708 		spin_lock(&block_group->lock);
2709 		block_group->alloc_offset -= size;
2710 		spin_unlock(&block_group->lock);
2711 	}
2712 
2713 	reclaimable_unusable = block_group->zone_unusable -
2714 			       (block_group->length - block_group->zone_capacity);
2715 	/* All the region is now unusable. Mark it as unused and reclaim */
2716 	if (block_group->zone_unusable == block_group->length) {
2717 		btrfs_mark_bg_unused(block_group);
2718 	} else if (bg_reclaim_threshold &&
2719 		   reclaimable_unusable >=
2720 		   div_factor_fine(block_group->zone_capacity,
2721 				   bg_reclaim_threshold)) {
2722 		btrfs_mark_bg_to_reclaim(block_group);
2723 	}
2724 
2725 	return 0;
2726 }
2727 
btrfs_add_free_space(struct btrfs_block_group * block_group,u64 bytenr,u64 size)2728 int btrfs_add_free_space(struct btrfs_block_group *block_group,
2729 			 u64 bytenr, u64 size)
2730 {
2731 	enum btrfs_trim_state trim_state = BTRFS_TRIM_STATE_UNTRIMMED;
2732 
2733 	if (btrfs_is_zoned(block_group->fs_info))
2734 		return __btrfs_add_free_space_zoned(block_group, bytenr, size,
2735 						    true);
2736 
2737 	if (btrfs_test_opt(block_group->fs_info, DISCARD_SYNC))
2738 		trim_state = BTRFS_TRIM_STATE_TRIMMED;
2739 
2740 	return __btrfs_add_free_space(block_group, bytenr, size, trim_state);
2741 }
2742 
btrfs_add_free_space_unused(struct btrfs_block_group * block_group,u64 bytenr,u64 size)2743 int btrfs_add_free_space_unused(struct btrfs_block_group *block_group,
2744 				u64 bytenr, u64 size)
2745 {
2746 	if (btrfs_is_zoned(block_group->fs_info))
2747 		return __btrfs_add_free_space_zoned(block_group, bytenr, size,
2748 						    false);
2749 
2750 	return btrfs_add_free_space(block_group, bytenr, size);
2751 }
2752 
2753 /*
2754  * This is a subtle distinction because when adding free space back in general,
2755  * we want it to be added as untrimmed for async. But in the case where we add
2756  * it on loading of a block group, we want to consider it trimmed.
2757  */
btrfs_add_free_space_async_trimmed(struct btrfs_block_group * block_group,u64 bytenr,u64 size)2758 int btrfs_add_free_space_async_trimmed(struct btrfs_block_group *block_group,
2759 				       u64 bytenr, u64 size)
2760 {
2761 	enum btrfs_trim_state trim_state = BTRFS_TRIM_STATE_UNTRIMMED;
2762 
2763 	if (btrfs_is_zoned(block_group->fs_info))
2764 		return __btrfs_add_free_space_zoned(block_group, bytenr, size,
2765 						    true);
2766 
2767 	if (btrfs_test_opt(block_group->fs_info, DISCARD_SYNC) ||
2768 	    btrfs_test_opt(block_group->fs_info, DISCARD_ASYNC))
2769 		trim_state = BTRFS_TRIM_STATE_TRIMMED;
2770 
2771 	return __btrfs_add_free_space(block_group, bytenr, size, trim_state);
2772 }
2773 
btrfs_remove_free_space(struct btrfs_block_group * block_group,u64 offset,u64 bytes)2774 int btrfs_remove_free_space(struct btrfs_block_group *block_group,
2775 			    u64 offset, u64 bytes)
2776 {
2777 	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2778 	struct btrfs_free_space *info;
2779 	int ret;
2780 	bool re_search = false;
2781 
2782 	if (btrfs_is_zoned(block_group->fs_info)) {
2783 		/*
2784 		 * This can happen with conventional zones when replaying log.
2785 		 * Since the allocation info of tree-log nodes are not recorded
2786 		 * to the extent-tree, calculate_alloc_pointer() failed to
2787 		 * advance the allocation pointer after last allocated tree log
2788 		 * node blocks.
2789 		 *
2790 		 * This function is called from
2791 		 * btrfs_pin_extent_for_log_replay() when replaying the log.
2792 		 * Advance the pointer not to overwrite the tree-log nodes.
2793 		 */
2794 		if (block_group->start + block_group->alloc_offset <
2795 		    offset + bytes) {
2796 			block_group->alloc_offset =
2797 				offset + bytes - block_group->start;
2798 		}
2799 		return 0;
2800 	}
2801 
2802 	spin_lock(&ctl->tree_lock);
2803 
2804 again:
2805 	ret = 0;
2806 	if (!bytes)
2807 		goto out_lock;
2808 
2809 	info = tree_search_offset(ctl, offset, 0, 0);
2810 	if (!info) {
2811 		/*
2812 		 * oops didn't find an extent that matched the space we wanted
2813 		 * to remove, look for a bitmap instead
2814 		 */
2815 		info = tree_search_offset(ctl, offset_to_bitmap(ctl, offset),
2816 					  1, 0);
2817 		if (!info) {
2818 			/*
2819 			 * If we found a partial bit of our free space in a
2820 			 * bitmap but then couldn't find the other part this may
2821 			 * be a problem, so WARN about it.
2822 			 */
2823 			WARN_ON(re_search);
2824 			goto out_lock;
2825 		}
2826 	}
2827 
2828 	re_search = false;
2829 	if (!info->bitmap) {
2830 		unlink_free_space(ctl, info, true);
2831 		if (offset == info->offset) {
2832 			u64 to_free = min(bytes, info->bytes);
2833 
2834 			info->bytes -= to_free;
2835 			info->offset += to_free;
2836 			if (info->bytes) {
2837 				ret = link_free_space(ctl, info);
2838 				WARN_ON(ret);
2839 			} else {
2840 				kmem_cache_free(btrfs_free_space_cachep, info);
2841 			}
2842 
2843 			offset += to_free;
2844 			bytes -= to_free;
2845 			goto again;
2846 		} else {
2847 			u64 old_end = info->bytes + info->offset;
2848 
2849 			info->bytes = offset - info->offset;
2850 			ret = link_free_space(ctl, info);
2851 			WARN_ON(ret);
2852 			if (ret)
2853 				goto out_lock;
2854 
2855 			/* Not enough bytes in this entry to satisfy us */
2856 			if (old_end < offset + bytes) {
2857 				bytes -= old_end - offset;
2858 				offset = old_end;
2859 				goto again;
2860 			} else if (old_end == offset + bytes) {
2861 				/* all done */
2862 				goto out_lock;
2863 			}
2864 			spin_unlock(&ctl->tree_lock);
2865 
2866 			ret = __btrfs_add_free_space(block_group,
2867 						     offset + bytes,
2868 						     old_end - (offset + bytes),
2869 						     info->trim_state);
2870 			WARN_ON(ret);
2871 			goto out;
2872 		}
2873 	}
2874 
2875 	ret = remove_from_bitmap(ctl, info, &offset, &bytes);
2876 	if (ret == -EAGAIN) {
2877 		re_search = true;
2878 		goto again;
2879 	}
2880 out_lock:
2881 	btrfs_discard_update_discardable(block_group);
2882 	spin_unlock(&ctl->tree_lock);
2883 out:
2884 	return ret;
2885 }
2886 
btrfs_dump_free_space(struct btrfs_block_group * block_group,u64 bytes)2887 void btrfs_dump_free_space(struct btrfs_block_group *block_group,
2888 			   u64 bytes)
2889 {
2890 	struct btrfs_fs_info *fs_info = block_group->fs_info;
2891 	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2892 	struct btrfs_free_space *info;
2893 	struct rb_node *n;
2894 	int count = 0;
2895 
2896 	/*
2897 	 * Zoned btrfs does not use free space tree and cluster. Just print
2898 	 * out the free space after the allocation offset.
2899 	 */
2900 	if (btrfs_is_zoned(fs_info)) {
2901 		btrfs_info(fs_info, "free space %llu active %d",
2902 			   block_group->zone_capacity - block_group->alloc_offset,
2903 			   test_bit(BLOCK_GROUP_FLAG_ZONE_IS_ACTIVE,
2904 				    &block_group->runtime_flags));
2905 		return;
2906 	}
2907 
2908 	spin_lock(&ctl->tree_lock);
2909 	for (n = rb_first(&ctl->free_space_offset); n; n = rb_next(n)) {
2910 		info = rb_entry(n, struct btrfs_free_space, offset_index);
2911 		if (info->bytes >= bytes && !block_group->ro)
2912 			count++;
2913 		btrfs_crit(fs_info, "entry offset %llu, bytes %llu, bitmap %s",
2914 			   info->offset, info->bytes,
2915 		       (info->bitmap) ? "yes" : "no");
2916 	}
2917 	spin_unlock(&ctl->tree_lock);
2918 	btrfs_info(fs_info, "block group has cluster?: %s",
2919 	       list_empty(&block_group->cluster_list) ? "no" : "yes");
2920 	btrfs_info(fs_info,
2921 		   "%d blocks of free space at or bigger than bytes is", count);
2922 }
2923 
btrfs_init_free_space_ctl(struct btrfs_block_group * block_group,struct btrfs_free_space_ctl * ctl)2924 void btrfs_init_free_space_ctl(struct btrfs_block_group *block_group,
2925 			       struct btrfs_free_space_ctl *ctl)
2926 {
2927 	struct btrfs_fs_info *fs_info = block_group->fs_info;
2928 
2929 	spin_lock_init(&ctl->tree_lock);
2930 	ctl->unit = fs_info->sectorsize;
2931 	ctl->start = block_group->start;
2932 	ctl->block_group = block_group;
2933 	ctl->op = &free_space_op;
2934 	ctl->free_space_bytes = RB_ROOT_CACHED;
2935 	INIT_LIST_HEAD(&ctl->trimming_ranges);
2936 	mutex_init(&ctl->cache_writeout_mutex);
2937 
2938 	/*
2939 	 * we only want to have 32k of ram per block group for keeping
2940 	 * track of free space, and if we pass 1/2 of that we want to
2941 	 * start converting things over to using bitmaps
2942 	 */
2943 	ctl->extents_thresh = (SZ_32K / 2) / sizeof(struct btrfs_free_space);
2944 }
2945 
2946 /*
2947  * for a given cluster, put all of its extents back into the free
2948  * space cache.  If the block group passed doesn't match the block group
2949  * pointed to by the cluster, someone else raced in and freed the
2950  * cluster already.  In that case, we just return without changing anything
2951  */
__btrfs_return_cluster_to_free_space(struct btrfs_block_group * block_group,struct btrfs_free_cluster * cluster)2952 static void __btrfs_return_cluster_to_free_space(
2953 			     struct btrfs_block_group *block_group,
2954 			     struct btrfs_free_cluster *cluster)
2955 {
2956 	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2957 	struct btrfs_free_space *entry;
2958 	struct rb_node *node;
2959 
2960 	spin_lock(&cluster->lock);
2961 	if (cluster->block_group != block_group) {
2962 		spin_unlock(&cluster->lock);
2963 		return;
2964 	}
2965 
2966 	cluster->block_group = NULL;
2967 	cluster->window_start = 0;
2968 	list_del_init(&cluster->block_group_list);
2969 
2970 	node = rb_first(&cluster->root);
2971 	while (node) {
2972 		bool bitmap;
2973 
2974 		entry = rb_entry(node, struct btrfs_free_space, offset_index);
2975 		node = rb_next(&entry->offset_index);
2976 		rb_erase(&entry->offset_index, &cluster->root);
2977 		RB_CLEAR_NODE(&entry->offset_index);
2978 
2979 		bitmap = (entry->bitmap != NULL);
2980 		if (!bitmap) {
2981 			/* Merging treats extents as if they were new */
2982 			if (!btrfs_free_space_trimmed(entry)) {
2983 				ctl->discardable_extents[BTRFS_STAT_CURR]--;
2984 				ctl->discardable_bytes[BTRFS_STAT_CURR] -=
2985 					entry->bytes;
2986 			}
2987 
2988 			try_merge_free_space(ctl, entry, false);
2989 			steal_from_bitmap(ctl, entry, false);
2990 
2991 			/* As we insert directly, update these statistics */
2992 			if (!btrfs_free_space_trimmed(entry)) {
2993 				ctl->discardable_extents[BTRFS_STAT_CURR]++;
2994 				ctl->discardable_bytes[BTRFS_STAT_CURR] +=
2995 					entry->bytes;
2996 			}
2997 		}
2998 		tree_insert_offset(&ctl->free_space_offset,
2999 				   entry->offset, &entry->offset_index, bitmap);
3000 		rb_add_cached(&entry->bytes_index, &ctl->free_space_bytes,
3001 			      entry_less);
3002 	}
3003 	cluster->root = RB_ROOT;
3004 	spin_unlock(&cluster->lock);
3005 	btrfs_put_block_group(block_group);
3006 }
3007 
btrfs_remove_free_space_cache(struct btrfs_block_group * block_group)3008 void btrfs_remove_free_space_cache(struct btrfs_block_group *block_group)
3009 {
3010 	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
3011 	struct btrfs_free_cluster *cluster;
3012 	struct list_head *head;
3013 
3014 	spin_lock(&ctl->tree_lock);
3015 	while ((head = block_group->cluster_list.next) !=
3016 	       &block_group->cluster_list) {
3017 		cluster = list_entry(head, struct btrfs_free_cluster,
3018 				     block_group_list);
3019 
3020 		WARN_ON(cluster->block_group != block_group);
3021 		__btrfs_return_cluster_to_free_space(block_group, cluster);
3022 
3023 		cond_resched_lock(&ctl->tree_lock);
3024 	}
3025 	__btrfs_remove_free_space_cache(ctl);
3026 	btrfs_discard_update_discardable(block_group);
3027 	spin_unlock(&ctl->tree_lock);
3028 
3029 }
3030 
3031 /**
3032  * btrfs_is_free_space_trimmed - see if everything is trimmed
3033  * @block_group: block_group of interest
3034  *
3035  * Walk @block_group's free space rb_tree to determine if everything is trimmed.
3036  */
btrfs_is_free_space_trimmed(struct btrfs_block_group * block_group)3037 bool btrfs_is_free_space_trimmed(struct btrfs_block_group *block_group)
3038 {
3039 	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
3040 	struct btrfs_free_space *info;
3041 	struct rb_node *node;
3042 	bool ret = true;
3043 
3044 	spin_lock(&ctl->tree_lock);
3045 	node = rb_first(&ctl->free_space_offset);
3046 
3047 	while (node) {
3048 		info = rb_entry(node, struct btrfs_free_space, offset_index);
3049 
3050 		if (!btrfs_free_space_trimmed(info)) {
3051 			ret = false;
3052 			break;
3053 		}
3054 
3055 		node = rb_next(node);
3056 	}
3057 
3058 	spin_unlock(&ctl->tree_lock);
3059 	return ret;
3060 }
3061 
btrfs_find_space_for_alloc(struct btrfs_block_group * block_group,u64 offset,u64 bytes,u64 empty_size,u64 * max_extent_size)3062 u64 btrfs_find_space_for_alloc(struct btrfs_block_group *block_group,
3063 			       u64 offset, u64 bytes, u64 empty_size,
3064 			       u64 *max_extent_size)
3065 {
3066 	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
3067 	struct btrfs_discard_ctl *discard_ctl =
3068 					&block_group->fs_info->discard_ctl;
3069 	struct btrfs_free_space *entry = NULL;
3070 	u64 bytes_search = bytes + empty_size;
3071 	u64 ret = 0;
3072 	u64 align_gap = 0;
3073 	u64 align_gap_len = 0;
3074 	enum btrfs_trim_state align_gap_trim_state = BTRFS_TRIM_STATE_UNTRIMMED;
3075 	bool use_bytes_index = (offset == block_group->start);
3076 
3077 	ASSERT(!btrfs_is_zoned(block_group->fs_info));
3078 
3079 	spin_lock(&ctl->tree_lock);
3080 	entry = find_free_space(ctl, &offset, &bytes_search,
3081 				block_group->full_stripe_len, max_extent_size,
3082 				use_bytes_index);
3083 	if (!entry)
3084 		goto out;
3085 
3086 	ret = offset;
3087 	if (entry->bitmap) {
3088 		bitmap_clear_bits(ctl, entry, offset, bytes, true);
3089 
3090 		if (!btrfs_free_space_trimmed(entry))
3091 			atomic64_add(bytes, &discard_ctl->discard_bytes_saved);
3092 
3093 		if (!entry->bytes)
3094 			free_bitmap(ctl, entry);
3095 	} else {
3096 		unlink_free_space(ctl, entry, true);
3097 		align_gap_len = offset - entry->offset;
3098 		align_gap = entry->offset;
3099 		align_gap_trim_state = entry->trim_state;
3100 
3101 		if (!btrfs_free_space_trimmed(entry))
3102 			atomic64_add(bytes, &discard_ctl->discard_bytes_saved);
3103 
3104 		entry->offset = offset + bytes;
3105 		WARN_ON(entry->bytes < bytes + align_gap_len);
3106 
3107 		entry->bytes -= bytes + align_gap_len;
3108 		if (!entry->bytes)
3109 			kmem_cache_free(btrfs_free_space_cachep, entry);
3110 		else
3111 			link_free_space(ctl, entry);
3112 	}
3113 out:
3114 	btrfs_discard_update_discardable(block_group);
3115 	spin_unlock(&ctl->tree_lock);
3116 
3117 	if (align_gap_len)
3118 		__btrfs_add_free_space(block_group, align_gap, align_gap_len,
3119 				       align_gap_trim_state);
3120 	return ret;
3121 }
3122 
3123 /*
3124  * given a cluster, put all of its extents back into the free space
3125  * cache.  If a block group is passed, this function will only free
3126  * a cluster that belongs to the passed block group.
3127  *
3128  * Otherwise, it'll get a reference on the block group pointed to by the
3129  * cluster and remove the cluster from it.
3130  */
btrfs_return_cluster_to_free_space(struct btrfs_block_group * block_group,struct btrfs_free_cluster * cluster)3131 void btrfs_return_cluster_to_free_space(
3132 			       struct btrfs_block_group *block_group,
3133 			       struct btrfs_free_cluster *cluster)
3134 {
3135 	struct btrfs_free_space_ctl *ctl;
3136 
3137 	/* first, get a safe pointer to the block group */
3138 	spin_lock(&cluster->lock);
3139 	if (!block_group) {
3140 		block_group = cluster->block_group;
3141 		if (!block_group) {
3142 			spin_unlock(&cluster->lock);
3143 			return;
3144 		}
3145 	} else if (cluster->block_group != block_group) {
3146 		/* someone else has already freed it don't redo their work */
3147 		spin_unlock(&cluster->lock);
3148 		return;
3149 	}
3150 	btrfs_get_block_group(block_group);
3151 	spin_unlock(&cluster->lock);
3152 
3153 	ctl = block_group->free_space_ctl;
3154 
3155 	/* now return any extents the cluster had on it */
3156 	spin_lock(&ctl->tree_lock);
3157 	__btrfs_return_cluster_to_free_space(block_group, cluster);
3158 	spin_unlock(&ctl->tree_lock);
3159 
3160 	btrfs_discard_queue_work(&block_group->fs_info->discard_ctl, block_group);
3161 
3162 	/* finally drop our ref */
3163 	btrfs_put_block_group(block_group);
3164 }
3165 
btrfs_alloc_from_bitmap(struct btrfs_block_group * block_group,struct btrfs_free_cluster * cluster,struct btrfs_free_space * entry,u64 bytes,u64 min_start,u64 * max_extent_size)3166 static u64 btrfs_alloc_from_bitmap(struct btrfs_block_group *block_group,
3167 				   struct btrfs_free_cluster *cluster,
3168 				   struct btrfs_free_space *entry,
3169 				   u64 bytes, u64 min_start,
3170 				   u64 *max_extent_size)
3171 {
3172 	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
3173 	int err;
3174 	u64 search_start = cluster->window_start;
3175 	u64 search_bytes = bytes;
3176 	u64 ret = 0;
3177 
3178 	search_start = min_start;
3179 	search_bytes = bytes;
3180 
3181 	err = search_bitmap(ctl, entry, &search_start, &search_bytes, true);
3182 	if (err) {
3183 		*max_extent_size = max(get_max_extent_size(entry),
3184 				       *max_extent_size);
3185 		return 0;
3186 	}
3187 
3188 	ret = search_start;
3189 	bitmap_clear_bits(ctl, entry, ret, bytes, false);
3190 
3191 	return ret;
3192 }
3193 
3194 /*
3195  * given a cluster, try to allocate 'bytes' from it, returns 0
3196  * if it couldn't find anything suitably large, or a logical disk offset
3197  * if things worked out
3198  */
btrfs_alloc_from_cluster(struct btrfs_block_group * block_group,struct btrfs_free_cluster * cluster,u64 bytes,u64 min_start,u64 * max_extent_size)3199 u64 btrfs_alloc_from_cluster(struct btrfs_block_group *block_group,
3200 			     struct btrfs_free_cluster *cluster, u64 bytes,
3201 			     u64 min_start, u64 *max_extent_size)
3202 {
3203 	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
3204 	struct btrfs_discard_ctl *discard_ctl =
3205 					&block_group->fs_info->discard_ctl;
3206 	struct btrfs_free_space *entry = NULL;
3207 	struct rb_node *node;
3208 	u64 ret = 0;
3209 
3210 	ASSERT(!btrfs_is_zoned(block_group->fs_info));
3211 
3212 	spin_lock(&cluster->lock);
3213 	if (bytes > cluster->max_size)
3214 		goto out;
3215 
3216 	if (cluster->block_group != block_group)
3217 		goto out;
3218 
3219 	node = rb_first(&cluster->root);
3220 	if (!node)
3221 		goto out;
3222 
3223 	entry = rb_entry(node, struct btrfs_free_space, offset_index);
3224 	while (1) {
3225 		if (entry->bytes < bytes)
3226 			*max_extent_size = max(get_max_extent_size(entry),
3227 					       *max_extent_size);
3228 
3229 		if (entry->bytes < bytes ||
3230 		    (!entry->bitmap && entry->offset < min_start)) {
3231 			node = rb_next(&entry->offset_index);
3232 			if (!node)
3233 				break;
3234 			entry = rb_entry(node, struct btrfs_free_space,
3235 					 offset_index);
3236 			continue;
3237 		}
3238 
3239 		if (entry->bitmap) {
3240 			ret = btrfs_alloc_from_bitmap(block_group,
3241 						      cluster, entry, bytes,
3242 						      cluster->window_start,
3243 						      max_extent_size);
3244 			if (ret == 0) {
3245 				node = rb_next(&entry->offset_index);
3246 				if (!node)
3247 					break;
3248 				entry = rb_entry(node, struct btrfs_free_space,
3249 						 offset_index);
3250 				continue;
3251 			}
3252 			cluster->window_start += bytes;
3253 		} else {
3254 			ret = entry->offset;
3255 
3256 			entry->offset += bytes;
3257 			entry->bytes -= bytes;
3258 		}
3259 
3260 		break;
3261 	}
3262 out:
3263 	spin_unlock(&cluster->lock);
3264 
3265 	if (!ret)
3266 		return 0;
3267 
3268 	spin_lock(&ctl->tree_lock);
3269 
3270 	if (!btrfs_free_space_trimmed(entry))
3271 		atomic64_add(bytes, &discard_ctl->discard_bytes_saved);
3272 
3273 	ctl->free_space -= bytes;
3274 	if (!entry->bitmap && !btrfs_free_space_trimmed(entry))
3275 		ctl->discardable_bytes[BTRFS_STAT_CURR] -= bytes;
3276 
3277 	spin_lock(&cluster->lock);
3278 	if (entry->bytes == 0) {
3279 		rb_erase(&entry->offset_index, &cluster->root);
3280 		ctl->free_extents--;
3281 		if (entry->bitmap) {
3282 			kmem_cache_free(btrfs_free_space_bitmap_cachep,
3283 					entry->bitmap);
3284 			ctl->total_bitmaps--;
3285 			recalculate_thresholds(ctl);
3286 		} else if (!btrfs_free_space_trimmed(entry)) {
3287 			ctl->discardable_extents[BTRFS_STAT_CURR]--;
3288 		}
3289 		kmem_cache_free(btrfs_free_space_cachep, entry);
3290 	}
3291 
3292 	spin_unlock(&cluster->lock);
3293 	spin_unlock(&ctl->tree_lock);
3294 
3295 	return ret;
3296 }
3297 
btrfs_bitmap_cluster(struct btrfs_block_group * block_group,struct btrfs_free_space * entry,struct btrfs_free_cluster * cluster,u64 offset,u64 bytes,u64 cont1_bytes,u64 min_bytes)3298 static int btrfs_bitmap_cluster(struct btrfs_block_group *block_group,
3299 				struct btrfs_free_space *entry,
3300 				struct btrfs_free_cluster *cluster,
3301 				u64 offset, u64 bytes,
3302 				u64 cont1_bytes, u64 min_bytes)
3303 {
3304 	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
3305 	unsigned long next_zero;
3306 	unsigned long i;
3307 	unsigned long want_bits;
3308 	unsigned long min_bits;
3309 	unsigned long found_bits;
3310 	unsigned long max_bits = 0;
3311 	unsigned long start = 0;
3312 	unsigned long total_found = 0;
3313 	int ret;
3314 
3315 	i = offset_to_bit(entry->offset, ctl->unit,
3316 			  max_t(u64, offset, entry->offset));
3317 	want_bits = bytes_to_bits(bytes, ctl->unit);
3318 	min_bits = bytes_to_bits(min_bytes, ctl->unit);
3319 
3320 	/*
3321 	 * Don't bother looking for a cluster in this bitmap if it's heavily
3322 	 * fragmented.
3323 	 */
3324 	if (entry->max_extent_size &&
3325 	    entry->max_extent_size < cont1_bytes)
3326 		return -ENOSPC;
3327 again:
3328 	found_bits = 0;
3329 	for_each_set_bit_from(i, entry->bitmap, BITS_PER_BITMAP) {
3330 		next_zero = find_next_zero_bit(entry->bitmap,
3331 					       BITS_PER_BITMAP, i);
3332 		if (next_zero - i >= min_bits) {
3333 			found_bits = next_zero - i;
3334 			if (found_bits > max_bits)
3335 				max_bits = found_bits;
3336 			break;
3337 		}
3338 		if (next_zero - i > max_bits)
3339 			max_bits = next_zero - i;
3340 		i = next_zero;
3341 	}
3342 
3343 	if (!found_bits) {
3344 		entry->max_extent_size = (u64)max_bits * ctl->unit;
3345 		return -ENOSPC;
3346 	}
3347 
3348 	if (!total_found) {
3349 		start = i;
3350 		cluster->max_size = 0;
3351 	}
3352 
3353 	total_found += found_bits;
3354 
3355 	if (cluster->max_size < found_bits * ctl->unit)
3356 		cluster->max_size = found_bits * ctl->unit;
3357 
3358 	if (total_found < want_bits || cluster->max_size < cont1_bytes) {
3359 		i = next_zero + 1;
3360 		goto again;
3361 	}
3362 
3363 	cluster->window_start = start * ctl->unit + entry->offset;
3364 	rb_erase(&entry->offset_index, &ctl->free_space_offset);
3365 	rb_erase_cached(&entry->bytes_index, &ctl->free_space_bytes);
3366 
3367 	/*
3368 	 * We need to know if we're currently on the normal space index when we
3369 	 * manipulate the bitmap so that we know we need to remove and re-insert
3370 	 * it into the space_index tree.  Clear the bytes_index node here so the
3371 	 * bitmap manipulation helpers know not to mess with the space_index
3372 	 * until this bitmap entry is added back into the normal cache.
3373 	 */
3374 	RB_CLEAR_NODE(&entry->bytes_index);
3375 
3376 	ret = tree_insert_offset(&cluster->root, entry->offset,
3377 				 &entry->offset_index, 1);
3378 	ASSERT(!ret); /* -EEXIST; Logic error */
3379 
3380 	trace_btrfs_setup_cluster(block_group, cluster,
3381 				  total_found * ctl->unit, 1);
3382 	return 0;
3383 }
3384 
3385 /*
3386  * This searches the block group for just extents to fill the cluster with.
3387  * Try to find a cluster with at least bytes total bytes, at least one
3388  * extent of cont1_bytes, and other clusters of at least min_bytes.
3389  */
3390 static noinline int
setup_cluster_no_bitmap(struct btrfs_block_group * block_group,struct btrfs_free_cluster * cluster,struct list_head * bitmaps,u64 offset,u64 bytes,u64 cont1_bytes,u64 min_bytes)3391 setup_cluster_no_bitmap(struct btrfs_block_group *block_group,
3392 			struct btrfs_free_cluster *cluster,
3393 			struct list_head *bitmaps, u64 offset, u64 bytes,
3394 			u64 cont1_bytes, u64 min_bytes)
3395 {
3396 	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
3397 	struct btrfs_free_space *first = NULL;
3398 	struct btrfs_free_space *entry = NULL;
3399 	struct btrfs_free_space *last;
3400 	struct rb_node *node;
3401 	u64 window_free;
3402 	u64 max_extent;
3403 	u64 total_size = 0;
3404 
3405 	entry = tree_search_offset(ctl, offset, 0, 1);
3406 	if (!entry)
3407 		return -ENOSPC;
3408 
3409 	/*
3410 	 * We don't want bitmaps, so just move along until we find a normal
3411 	 * extent entry.
3412 	 */
3413 	while (entry->bitmap || entry->bytes < min_bytes) {
3414 		if (entry->bitmap && list_empty(&entry->list))
3415 			list_add_tail(&entry->list, bitmaps);
3416 		node = rb_next(&entry->offset_index);
3417 		if (!node)
3418 			return -ENOSPC;
3419 		entry = rb_entry(node, struct btrfs_free_space, offset_index);
3420 	}
3421 
3422 	window_free = entry->bytes;
3423 	max_extent = entry->bytes;
3424 	first = entry;
3425 	last = entry;
3426 
3427 	for (node = rb_next(&entry->offset_index); node;
3428 	     node = rb_next(&entry->offset_index)) {
3429 		entry = rb_entry(node, struct btrfs_free_space, offset_index);
3430 
3431 		if (entry->bitmap) {
3432 			if (list_empty(&entry->list))
3433 				list_add_tail(&entry->list, bitmaps);
3434 			continue;
3435 		}
3436 
3437 		if (entry->bytes < min_bytes)
3438 			continue;
3439 
3440 		last = entry;
3441 		window_free += entry->bytes;
3442 		if (entry->bytes > max_extent)
3443 			max_extent = entry->bytes;
3444 	}
3445 
3446 	if (window_free < bytes || max_extent < cont1_bytes)
3447 		return -ENOSPC;
3448 
3449 	cluster->window_start = first->offset;
3450 
3451 	node = &first->offset_index;
3452 
3453 	/*
3454 	 * now we've found our entries, pull them out of the free space
3455 	 * cache and put them into the cluster rbtree
3456 	 */
3457 	do {
3458 		int ret;
3459 
3460 		entry = rb_entry(node, struct btrfs_free_space, offset_index);
3461 		node = rb_next(&entry->offset_index);
3462 		if (entry->bitmap || entry->bytes < min_bytes)
3463 			continue;
3464 
3465 		rb_erase(&entry->offset_index, &ctl->free_space_offset);
3466 		rb_erase_cached(&entry->bytes_index, &ctl->free_space_bytes);
3467 		ret = tree_insert_offset(&cluster->root, entry->offset,
3468 					 &entry->offset_index, 0);
3469 		total_size += entry->bytes;
3470 		ASSERT(!ret); /* -EEXIST; Logic error */
3471 	} while (node && entry != last);
3472 
3473 	cluster->max_size = max_extent;
3474 	trace_btrfs_setup_cluster(block_group, cluster, total_size, 0);
3475 	return 0;
3476 }
3477 
3478 /*
3479  * This specifically looks for bitmaps that may work in the cluster, we assume
3480  * that we have already failed to find extents that will work.
3481  */
3482 static noinline int
setup_cluster_bitmap(struct btrfs_block_group * block_group,struct btrfs_free_cluster * cluster,struct list_head * bitmaps,u64 offset,u64 bytes,u64 cont1_bytes,u64 min_bytes)3483 setup_cluster_bitmap(struct btrfs_block_group *block_group,
3484 		     struct btrfs_free_cluster *cluster,
3485 		     struct list_head *bitmaps, u64 offset, u64 bytes,
3486 		     u64 cont1_bytes, u64 min_bytes)
3487 {
3488 	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
3489 	struct btrfs_free_space *entry = NULL;
3490 	int ret = -ENOSPC;
3491 	u64 bitmap_offset = offset_to_bitmap(ctl, offset);
3492 
3493 	if (ctl->total_bitmaps == 0)
3494 		return -ENOSPC;
3495 
3496 	/*
3497 	 * The bitmap that covers offset won't be in the list unless offset
3498 	 * is just its start offset.
3499 	 */
3500 	if (!list_empty(bitmaps))
3501 		entry = list_first_entry(bitmaps, struct btrfs_free_space, list);
3502 
3503 	if (!entry || entry->offset != bitmap_offset) {
3504 		entry = tree_search_offset(ctl, bitmap_offset, 1, 0);
3505 		if (entry && list_empty(&entry->list))
3506 			list_add(&entry->list, bitmaps);
3507 	}
3508 
3509 	list_for_each_entry(entry, bitmaps, list) {
3510 		if (entry->bytes < bytes)
3511 			continue;
3512 		ret = btrfs_bitmap_cluster(block_group, entry, cluster, offset,
3513 					   bytes, cont1_bytes, min_bytes);
3514 		if (!ret)
3515 			return 0;
3516 	}
3517 
3518 	/*
3519 	 * The bitmaps list has all the bitmaps that record free space
3520 	 * starting after offset, so no more search is required.
3521 	 */
3522 	return -ENOSPC;
3523 }
3524 
3525 /*
3526  * here we try to find a cluster of blocks in a block group.  The goal
3527  * is to find at least bytes+empty_size.
3528  * We might not find them all in one contiguous area.
3529  *
3530  * returns zero and sets up cluster if things worked out, otherwise
3531  * it returns -enospc
3532  */
btrfs_find_space_cluster(struct btrfs_block_group * block_group,struct btrfs_free_cluster * cluster,u64 offset,u64 bytes,u64 empty_size)3533 int btrfs_find_space_cluster(struct btrfs_block_group *block_group,
3534 			     struct btrfs_free_cluster *cluster,
3535 			     u64 offset, u64 bytes, u64 empty_size)
3536 {
3537 	struct btrfs_fs_info *fs_info = block_group->fs_info;
3538 	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
3539 	struct btrfs_free_space *entry, *tmp;
3540 	LIST_HEAD(bitmaps);
3541 	u64 min_bytes;
3542 	u64 cont1_bytes;
3543 	int ret;
3544 
3545 	/*
3546 	 * Choose the minimum extent size we'll require for this
3547 	 * cluster.  For SSD_SPREAD, don't allow any fragmentation.
3548 	 * For metadata, allow allocates with smaller extents.  For
3549 	 * data, keep it dense.
3550 	 */
3551 	if (btrfs_test_opt(fs_info, SSD_SPREAD)) {
3552 		cont1_bytes = bytes + empty_size;
3553 		min_bytes = cont1_bytes;
3554 	} else if (block_group->flags & BTRFS_BLOCK_GROUP_METADATA) {
3555 		cont1_bytes = bytes;
3556 		min_bytes = fs_info->sectorsize;
3557 	} else {
3558 		cont1_bytes = max(bytes, (bytes + empty_size) >> 2);
3559 		min_bytes = fs_info->sectorsize;
3560 	}
3561 
3562 	spin_lock(&ctl->tree_lock);
3563 
3564 	/*
3565 	 * If we know we don't have enough space to make a cluster don't even
3566 	 * bother doing all the work to try and find one.
3567 	 */
3568 	if (ctl->free_space < bytes) {
3569 		spin_unlock(&ctl->tree_lock);
3570 		return -ENOSPC;
3571 	}
3572 
3573 	spin_lock(&cluster->lock);
3574 
3575 	/* someone already found a cluster, hooray */
3576 	if (cluster->block_group) {
3577 		ret = 0;
3578 		goto out;
3579 	}
3580 
3581 	trace_btrfs_find_cluster(block_group, offset, bytes, empty_size,
3582 				 min_bytes);
3583 
3584 	ret = setup_cluster_no_bitmap(block_group, cluster, &bitmaps, offset,
3585 				      bytes + empty_size,
3586 				      cont1_bytes, min_bytes);
3587 	if (ret)
3588 		ret = setup_cluster_bitmap(block_group, cluster, &bitmaps,
3589 					   offset, bytes + empty_size,
3590 					   cont1_bytes, min_bytes);
3591 
3592 	/* Clear our temporary list */
3593 	list_for_each_entry_safe(entry, tmp, &bitmaps, list)
3594 		list_del_init(&entry->list);
3595 
3596 	if (!ret) {
3597 		btrfs_get_block_group(block_group);
3598 		list_add_tail(&cluster->block_group_list,
3599 			      &block_group->cluster_list);
3600 		cluster->block_group = block_group;
3601 	} else {
3602 		trace_btrfs_failed_cluster_setup(block_group);
3603 	}
3604 out:
3605 	spin_unlock(&cluster->lock);
3606 	spin_unlock(&ctl->tree_lock);
3607 
3608 	return ret;
3609 }
3610 
3611 /*
3612  * simple code to zero out a cluster
3613  */
btrfs_init_free_cluster(struct btrfs_free_cluster * cluster)3614 void btrfs_init_free_cluster(struct btrfs_free_cluster *cluster)
3615 {
3616 	spin_lock_init(&cluster->lock);
3617 	spin_lock_init(&cluster->refill_lock);
3618 	cluster->root = RB_ROOT;
3619 	cluster->max_size = 0;
3620 	cluster->fragmented = false;
3621 	INIT_LIST_HEAD(&cluster->block_group_list);
3622 	cluster->block_group = NULL;
3623 }
3624 
do_trimming(struct btrfs_block_group * block_group,u64 * total_trimmed,u64 start,u64 bytes,u64 reserved_start,u64 reserved_bytes,enum btrfs_trim_state reserved_trim_state,struct btrfs_trim_range * trim_entry)3625 static int do_trimming(struct btrfs_block_group *block_group,
3626 		       u64 *total_trimmed, u64 start, u64 bytes,
3627 		       u64 reserved_start, u64 reserved_bytes,
3628 		       enum btrfs_trim_state reserved_trim_state,
3629 		       struct btrfs_trim_range *trim_entry)
3630 {
3631 	struct btrfs_space_info *space_info = block_group->space_info;
3632 	struct btrfs_fs_info *fs_info = block_group->fs_info;
3633 	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
3634 	int ret;
3635 	int update = 0;
3636 	const u64 end = start + bytes;
3637 	const u64 reserved_end = reserved_start + reserved_bytes;
3638 	enum btrfs_trim_state trim_state = BTRFS_TRIM_STATE_UNTRIMMED;
3639 	u64 trimmed = 0;
3640 
3641 	spin_lock(&space_info->lock);
3642 	spin_lock(&block_group->lock);
3643 	if (!block_group->ro) {
3644 		block_group->reserved += reserved_bytes;
3645 		space_info->bytes_reserved += reserved_bytes;
3646 		update = 1;
3647 	}
3648 	spin_unlock(&block_group->lock);
3649 	spin_unlock(&space_info->lock);
3650 
3651 	ret = btrfs_discard_extent(fs_info, start, bytes, &trimmed);
3652 	if (!ret) {
3653 		*total_trimmed += trimmed;
3654 		trim_state = BTRFS_TRIM_STATE_TRIMMED;
3655 	}
3656 
3657 	mutex_lock(&ctl->cache_writeout_mutex);
3658 	if (reserved_start < start)
3659 		__btrfs_add_free_space(block_group, reserved_start,
3660 				       start - reserved_start,
3661 				       reserved_trim_state);
3662 	if (start + bytes < reserved_start + reserved_bytes)
3663 		__btrfs_add_free_space(block_group, end, reserved_end - end,
3664 				       reserved_trim_state);
3665 	__btrfs_add_free_space(block_group, start, bytes, trim_state);
3666 	list_del(&trim_entry->list);
3667 	mutex_unlock(&ctl->cache_writeout_mutex);
3668 
3669 	if (update) {
3670 		spin_lock(&space_info->lock);
3671 		spin_lock(&block_group->lock);
3672 		if (block_group->ro)
3673 			space_info->bytes_readonly += reserved_bytes;
3674 		block_group->reserved -= reserved_bytes;
3675 		space_info->bytes_reserved -= reserved_bytes;
3676 		spin_unlock(&block_group->lock);
3677 		spin_unlock(&space_info->lock);
3678 	}
3679 
3680 	return ret;
3681 }
3682 
3683 /*
3684  * If @async is set, then we will trim 1 region and return.
3685  */
trim_no_bitmap(struct btrfs_block_group * block_group,u64 * total_trimmed,u64 start,u64 end,u64 minlen,bool async)3686 static int trim_no_bitmap(struct btrfs_block_group *block_group,
3687 			  u64 *total_trimmed, u64 start, u64 end, u64 minlen,
3688 			  bool async)
3689 {
3690 	struct btrfs_discard_ctl *discard_ctl =
3691 					&block_group->fs_info->discard_ctl;
3692 	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
3693 	struct btrfs_free_space *entry;
3694 	struct rb_node *node;
3695 	int ret = 0;
3696 	u64 extent_start;
3697 	u64 extent_bytes;
3698 	enum btrfs_trim_state extent_trim_state;
3699 	u64 bytes;
3700 	const u64 max_discard_size = READ_ONCE(discard_ctl->max_discard_size);
3701 
3702 	while (start < end) {
3703 		struct btrfs_trim_range trim_entry;
3704 
3705 		mutex_lock(&ctl->cache_writeout_mutex);
3706 		spin_lock(&ctl->tree_lock);
3707 
3708 		if (ctl->free_space < minlen)
3709 			goto out_unlock;
3710 
3711 		entry = tree_search_offset(ctl, start, 0, 1);
3712 		if (!entry)
3713 			goto out_unlock;
3714 
3715 		/* Skip bitmaps and if async, already trimmed entries */
3716 		while (entry->bitmap ||
3717 		       (async && btrfs_free_space_trimmed(entry))) {
3718 			node = rb_next(&entry->offset_index);
3719 			if (!node)
3720 				goto out_unlock;
3721 			entry = rb_entry(node, struct btrfs_free_space,
3722 					 offset_index);
3723 		}
3724 
3725 		if (entry->offset >= end)
3726 			goto out_unlock;
3727 
3728 		extent_start = entry->offset;
3729 		extent_bytes = entry->bytes;
3730 		extent_trim_state = entry->trim_state;
3731 		if (async) {
3732 			start = entry->offset;
3733 			bytes = entry->bytes;
3734 			if (bytes < minlen) {
3735 				spin_unlock(&ctl->tree_lock);
3736 				mutex_unlock(&ctl->cache_writeout_mutex);
3737 				goto next;
3738 			}
3739 			unlink_free_space(ctl, entry, true);
3740 			/*
3741 			 * Let bytes = BTRFS_MAX_DISCARD_SIZE + X.
3742 			 * If X < BTRFS_ASYNC_DISCARD_MIN_FILTER, we won't trim
3743 			 * X when we come back around.  So trim it now.
3744 			 */
3745 			if (max_discard_size &&
3746 			    bytes >= (max_discard_size +
3747 				      BTRFS_ASYNC_DISCARD_MIN_FILTER)) {
3748 				bytes = max_discard_size;
3749 				extent_bytes = max_discard_size;
3750 				entry->offset += max_discard_size;
3751 				entry->bytes -= max_discard_size;
3752 				link_free_space(ctl, entry);
3753 			} else {
3754 				kmem_cache_free(btrfs_free_space_cachep, entry);
3755 			}
3756 		} else {
3757 			start = max(start, extent_start);
3758 			bytes = min(extent_start + extent_bytes, end) - start;
3759 			if (bytes < minlen) {
3760 				spin_unlock(&ctl->tree_lock);
3761 				mutex_unlock(&ctl->cache_writeout_mutex);
3762 				goto next;
3763 			}
3764 
3765 			unlink_free_space(ctl, entry, true);
3766 			kmem_cache_free(btrfs_free_space_cachep, entry);
3767 		}
3768 
3769 		spin_unlock(&ctl->tree_lock);
3770 		trim_entry.start = extent_start;
3771 		trim_entry.bytes = extent_bytes;
3772 		list_add_tail(&trim_entry.list, &ctl->trimming_ranges);
3773 		mutex_unlock(&ctl->cache_writeout_mutex);
3774 
3775 		ret = do_trimming(block_group, total_trimmed, start, bytes,
3776 				  extent_start, extent_bytes, extent_trim_state,
3777 				  &trim_entry);
3778 		if (ret) {
3779 			block_group->discard_cursor = start + bytes;
3780 			break;
3781 		}
3782 next:
3783 		start += bytes;
3784 		block_group->discard_cursor = start;
3785 		if (async && *total_trimmed)
3786 			break;
3787 
3788 		if (fatal_signal_pending(current)) {
3789 			ret = -ERESTARTSYS;
3790 			break;
3791 		}
3792 
3793 		cond_resched();
3794 	}
3795 
3796 	return ret;
3797 
3798 out_unlock:
3799 	block_group->discard_cursor = btrfs_block_group_end(block_group);
3800 	spin_unlock(&ctl->tree_lock);
3801 	mutex_unlock(&ctl->cache_writeout_mutex);
3802 
3803 	return ret;
3804 }
3805 
3806 /*
3807  * If we break out of trimming a bitmap prematurely, we should reset the
3808  * trimming bit.  In a rather contrieved case, it's possible to race here so
3809  * reset the state to BTRFS_TRIM_STATE_UNTRIMMED.
3810  *
3811  * start = start of bitmap
3812  * end = near end of bitmap
3813  *
3814  * Thread 1:			Thread 2:
3815  * trim_bitmaps(start)
3816  *				trim_bitmaps(end)
3817  *				end_trimming_bitmap()
3818  * reset_trimming_bitmap()
3819  */
reset_trimming_bitmap(struct btrfs_free_space_ctl * ctl,u64 offset)3820 static void reset_trimming_bitmap(struct btrfs_free_space_ctl *ctl, u64 offset)
3821 {
3822 	struct btrfs_free_space *entry;
3823 
3824 	spin_lock(&ctl->tree_lock);
3825 	entry = tree_search_offset(ctl, offset, 1, 0);
3826 	if (entry) {
3827 		if (btrfs_free_space_trimmed(entry)) {
3828 			ctl->discardable_extents[BTRFS_STAT_CURR] +=
3829 				entry->bitmap_extents;
3830 			ctl->discardable_bytes[BTRFS_STAT_CURR] += entry->bytes;
3831 		}
3832 		entry->trim_state = BTRFS_TRIM_STATE_UNTRIMMED;
3833 	}
3834 
3835 	spin_unlock(&ctl->tree_lock);
3836 }
3837 
end_trimming_bitmap(struct btrfs_free_space_ctl * ctl,struct btrfs_free_space * entry)3838 static void end_trimming_bitmap(struct btrfs_free_space_ctl *ctl,
3839 				struct btrfs_free_space *entry)
3840 {
3841 	if (btrfs_free_space_trimming_bitmap(entry)) {
3842 		entry->trim_state = BTRFS_TRIM_STATE_TRIMMED;
3843 		ctl->discardable_extents[BTRFS_STAT_CURR] -=
3844 			entry->bitmap_extents;
3845 		ctl->discardable_bytes[BTRFS_STAT_CURR] -= entry->bytes;
3846 	}
3847 }
3848 
3849 /*
3850  * If @async is set, then we will trim 1 region and return.
3851  */
trim_bitmaps(struct btrfs_block_group * block_group,u64 * total_trimmed,u64 start,u64 end,u64 minlen,u64 maxlen,bool async)3852 static int trim_bitmaps(struct btrfs_block_group *block_group,
3853 			u64 *total_trimmed, u64 start, u64 end, u64 minlen,
3854 			u64 maxlen, bool async)
3855 {
3856 	struct btrfs_discard_ctl *discard_ctl =
3857 					&block_group->fs_info->discard_ctl;
3858 	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
3859 	struct btrfs_free_space *entry;
3860 	int ret = 0;
3861 	int ret2;
3862 	u64 bytes;
3863 	u64 offset = offset_to_bitmap(ctl, start);
3864 	const u64 max_discard_size = READ_ONCE(discard_ctl->max_discard_size);
3865 
3866 	while (offset < end) {
3867 		bool next_bitmap = false;
3868 		struct btrfs_trim_range trim_entry;
3869 
3870 		mutex_lock(&ctl->cache_writeout_mutex);
3871 		spin_lock(&ctl->tree_lock);
3872 
3873 		if (ctl->free_space < minlen) {
3874 			block_group->discard_cursor =
3875 				btrfs_block_group_end(block_group);
3876 			spin_unlock(&ctl->tree_lock);
3877 			mutex_unlock(&ctl->cache_writeout_mutex);
3878 			break;
3879 		}
3880 
3881 		entry = tree_search_offset(ctl, offset, 1, 0);
3882 		/*
3883 		 * Bitmaps are marked trimmed lossily now to prevent constant
3884 		 * discarding of the same bitmap (the reason why we are bound
3885 		 * by the filters).  So, retrim the block group bitmaps when we
3886 		 * are preparing to punt to the unused_bgs list.  This uses
3887 		 * @minlen to determine if we are in BTRFS_DISCARD_INDEX_UNUSED
3888 		 * which is the only discard index which sets minlen to 0.
3889 		 */
3890 		if (!entry || (async && minlen && start == offset &&
3891 			       btrfs_free_space_trimmed(entry))) {
3892 			spin_unlock(&ctl->tree_lock);
3893 			mutex_unlock(&ctl->cache_writeout_mutex);
3894 			next_bitmap = true;
3895 			goto next;
3896 		}
3897 
3898 		/*
3899 		 * Async discard bitmap trimming begins at by setting the start
3900 		 * to be key.objectid and the offset_to_bitmap() aligns to the
3901 		 * start of the bitmap.  This lets us know we are fully
3902 		 * scanning the bitmap rather than only some portion of it.
3903 		 */
3904 		if (start == offset)
3905 			entry->trim_state = BTRFS_TRIM_STATE_TRIMMING;
3906 
3907 		bytes = minlen;
3908 		ret2 = search_bitmap(ctl, entry, &start, &bytes, false);
3909 		if (ret2 || start >= end) {
3910 			/*
3911 			 * We lossily consider a bitmap trimmed if we only skip
3912 			 * over regions <= BTRFS_ASYNC_DISCARD_MIN_FILTER.
3913 			 */
3914 			if (ret2 && minlen <= BTRFS_ASYNC_DISCARD_MIN_FILTER)
3915 				end_trimming_bitmap(ctl, entry);
3916 			else
3917 				entry->trim_state = BTRFS_TRIM_STATE_UNTRIMMED;
3918 			spin_unlock(&ctl->tree_lock);
3919 			mutex_unlock(&ctl->cache_writeout_mutex);
3920 			next_bitmap = true;
3921 			goto next;
3922 		}
3923 
3924 		/*
3925 		 * We already trimmed a region, but are using the locking above
3926 		 * to reset the trim_state.
3927 		 */
3928 		if (async && *total_trimmed) {
3929 			spin_unlock(&ctl->tree_lock);
3930 			mutex_unlock(&ctl->cache_writeout_mutex);
3931 			goto out;
3932 		}
3933 
3934 		bytes = min(bytes, end - start);
3935 		if (bytes < minlen || (async && maxlen && bytes > maxlen)) {
3936 			spin_unlock(&ctl->tree_lock);
3937 			mutex_unlock(&ctl->cache_writeout_mutex);
3938 			goto next;
3939 		}
3940 
3941 		/*
3942 		 * Let bytes = BTRFS_MAX_DISCARD_SIZE + X.
3943 		 * If X < @minlen, we won't trim X when we come back around.
3944 		 * So trim it now.  We differ here from trimming extents as we
3945 		 * don't keep individual state per bit.
3946 		 */
3947 		if (async &&
3948 		    max_discard_size &&
3949 		    bytes > (max_discard_size + minlen))
3950 			bytes = max_discard_size;
3951 
3952 		bitmap_clear_bits(ctl, entry, start, bytes, true);
3953 		if (entry->bytes == 0)
3954 			free_bitmap(ctl, entry);
3955 
3956 		spin_unlock(&ctl->tree_lock);
3957 		trim_entry.start = start;
3958 		trim_entry.bytes = bytes;
3959 		list_add_tail(&trim_entry.list, &ctl->trimming_ranges);
3960 		mutex_unlock(&ctl->cache_writeout_mutex);
3961 
3962 		ret = do_trimming(block_group, total_trimmed, start, bytes,
3963 				  start, bytes, 0, &trim_entry);
3964 		if (ret) {
3965 			reset_trimming_bitmap(ctl, offset);
3966 			block_group->discard_cursor =
3967 				btrfs_block_group_end(block_group);
3968 			break;
3969 		}
3970 next:
3971 		if (next_bitmap) {
3972 			offset += BITS_PER_BITMAP * ctl->unit;
3973 			start = offset;
3974 		} else {
3975 			start += bytes;
3976 		}
3977 		block_group->discard_cursor = start;
3978 
3979 		if (fatal_signal_pending(current)) {
3980 			if (start != offset)
3981 				reset_trimming_bitmap(ctl, offset);
3982 			ret = -ERESTARTSYS;
3983 			break;
3984 		}
3985 
3986 		cond_resched();
3987 	}
3988 
3989 	if (offset >= end)
3990 		block_group->discard_cursor = end;
3991 
3992 out:
3993 	return ret;
3994 }
3995 
btrfs_trim_block_group(struct btrfs_block_group * block_group,u64 * trimmed,u64 start,u64 end,u64 minlen)3996 int btrfs_trim_block_group(struct btrfs_block_group *block_group,
3997 			   u64 *trimmed, u64 start, u64 end, u64 minlen)
3998 {
3999 	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
4000 	int ret;
4001 	u64 rem = 0;
4002 
4003 	ASSERT(!btrfs_is_zoned(block_group->fs_info));
4004 
4005 	*trimmed = 0;
4006 
4007 	spin_lock(&block_group->lock);
4008 	if (test_bit(BLOCK_GROUP_FLAG_REMOVED, &block_group->runtime_flags)) {
4009 		spin_unlock(&block_group->lock);
4010 		return 0;
4011 	}
4012 	btrfs_freeze_block_group(block_group);
4013 	spin_unlock(&block_group->lock);
4014 
4015 	ret = trim_no_bitmap(block_group, trimmed, start, end, minlen, false);
4016 	if (ret)
4017 		goto out;
4018 
4019 	ret = trim_bitmaps(block_group, trimmed, start, end, minlen, 0, false);
4020 	div64_u64_rem(end, BITS_PER_BITMAP * ctl->unit, &rem);
4021 	/* If we ended in the middle of a bitmap, reset the trimming flag */
4022 	if (rem)
4023 		reset_trimming_bitmap(ctl, offset_to_bitmap(ctl, end));
4024 out:
4025 	btrfs_unfreeze_block_group(block_group);
4026 	return ret;
4027 }
4028 
btrfs_trim_block_group_extents(struct btrfs_block_group * block_group,u64 * trimmed,u64 start,u64 end,u64 minlen,bool async)4029 int btrfs_trim_block_group_extents(struct btrfs_block_group *block_group,
4030 				   u64 *trimmed, u64 start, u64 end, u64 minlen,
4031 				   bool async)
4032 {
4033 	int ret;
4034 
4035 	*trimmed = 0;
4036 
4037 	spin_lock(&block_group->lock);
4038 	if (test_bit(BLOCK_GROUP_FLAG_REMOVED, &block_group->runtime_flags)) {
4039 		spin_unlock(&block_group->lock);
4040 		return 0;
4041 	}
4042 	btrfs_freeze_block_group(block_group);
4043 	spin_unlock(&block_group->lock);
4044 
4045 	ret = trim_no_bitmap(block_group, trimmed, start, end, minlen, async);
4046 	btrfs_unfreeze_block_group(block_group);
4047 
4048 	return ret;
4049 }
4050 
btrfs_trim_block_group_bitmaps(struct btrfs_block_group * block_group,u64 * trimmed,u64 start,u64 end,u64 minlen,u64 maxlen,bool async)4051 int btrfs_trim_block_group_bitmaps(struct btrfs_block_group *block_group,
4052 				   u64 *trimmed, u64 start, u64 end, u64 minlen,
4053 				   u64 maxlen, bool async)
4054 {
4055 	int ret;
4056 
4057 	*trimmed = 0;
4058 
4059 	spin_lock(&block_group->lock);
4060 	if (test_bit(BLOCK_GROUP_FLAG_REMOVED, &block_group->runtime_flags)) {
4061 		spin_unlock(&block_group->lock);
4062 		return 0;
4063 	}
4064 	btrfs_freeze_block_group(block_group);
4065 	spin_unlock(&block_group->lock);
4066 
4067 	ret = trim_bitmaps(block_group, trimmed, start, end, minlen, maxlen,
4068 			   async);
4069 
4070 	btrfs_unfreeze_block_group(block_group);
4071 
4072 	return ret;
4073 }
4074 
btrfs_free_space_cache_v1_active(struct btrfs_fs_info * fs_info)4075 bool btrfs_free_space_cache_v1_active(struct btrfs_fs_info *fs_info)
4076 {
4077 	return btrfs_super_cache_generation(fs_info->super_copy);
4078 }
4079 
cleanup_free_space_cache_v1(struct btrfs_fs_info * fs_info,struct btrfs_trans_handle * trans)4080 static int cleanup_free_space_cache_v1(struct btrfs_fs_info *fs_info,
4081 				       struct btrfs_trans_handle *trans)
4082 {
4083 	struct btrfs_block_group *block_group;
4084 	struct rb_node *node;
4085 	int ret = 0;
4086 
4087 	btrfs_info(fs_info, "cleaning free space cache v1");
4088 
4089 	node = rb_first_cached(&fs_info->block_group_cache_tree);
4090 	while (node) {
4091 		block_group = rb_entry(node, struct btrfs_block_group, cache_node);
4092 		ret = btrfs_remove_free_space_inode(trans, NULL, block_group);
4093 		if (ret)
4094 			goto out;
4095 		node = rb_next(node);
4096 	}
4097 out:
4098 	return ret;
4099 }
4100 
btrfs_set_free_space_cache_v1_active(struct btrfs_fs_info * fs_info,bool active)4101 int btrfs_set_free_space_cache_v1_active(struct btrfs_fs_info *fs_info, bool active)
4102 {
4103 	struct btrfs_trans_handle *trans;
4104 	int ret;
4105 
4106 	/*
4107 	 * update_super_roots will appropriately set or unset
4108 	 * super_copy->cache_generation based on SPACE_CACHE and
4109 	 * BTRFS_FS_CLEANUP_SPACE_CACHE_V1. For this reason, we need a
4110 	 * transaction commit whether we are enabling space cache v1 and don't
4111 	 * have any other work to do, or are disabling it and removing free
4112 	 * space inodes.
4113 	 */
4114 	trans = btrfs_start_transaction(fs_info->tree_root, 0);
4115 	if (IS_ERR(trans))
4116 		return PTR_ERR(trans);
4117 
4118 	if (!active) {
4119 		set_bit(BTRFS_FS_CLEANUP_SPACE_CACHE_V1, &fs_info->flags);
4120 		ret = cleanup_free_space_cache_v1(fs_info, trans);
4121 		if (ret) {
4122 			btrfs_abort_transaction(trans, ret);
4123 			btrfs_end_transaction(trans);
4124 			goto out;
4125 		}
4126 	}
4127 
4128 	ret = btrfs_commit_transaction(trans);
4129 out:
4130 	clear_bit(BTRFS_FS_CLEANUP_SPACE_CACHE_V1, &fs_info->flags);
4131 
4132 	return ret;
4133 }
4134 
4135 #ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
4136 /*
4137  * Use this if you need to make a bitmap or extent entry specifically, it
4138  * doesn't do any of the merging that add_free_space does, this acts a lot like
4139  * how the free space cache loading stuff works, so you can get really weird
4140  * configurations.
4141  */
test_add_free_space_entry(struct btrfs_block_group * cache,u64 offset,u64 bytes,bool bitmap)4142 int test_add_free_space_entry(struct btrfs_block_group *cache,
4143 			      u64 offset, u64 bytes, bool bitmap)
4144 {
4145 	struct btrfs_free_space_ctl *ctl = cache->free_space_ctl;
4146 	struct btrfs_free_space *info = NULL, *bitmap_info;
4147 	void *map = NULL;
4148 	enum btrfs_trim_state trim_state = BTRFS_TRIM_STATE_TRIMMED;
4149 	u64 bytes_added;
4150 	int ret;
4151 
4152 again:
4153 	if (!info) {
4154 		info = kmem_cache_zalloc(btrfs_free_space_cachep, GFP_NOFS);
4155 		if (!info)
4156 			return -ENOMEM;
4157 	}
4158 
4159 	if (!bitmap) {
4160 		spin_lock(&ctl->tree_lock);
4161 		info->offset = offset;
4162 		info->bytes = bytes;
4163 		info->max_extent_size = 0;
4164 		ret = link_free_space(ctl, info);
4165 		spin_unlock(&ctl->tree_lock);
4166 		if (ret)
4167 			kmem_cache_free(btrfs_free_space_cachep, info);
4168 		return ret;
4169 	}
4170 
4171 	if (!map) {
4172 		map = kmem_cache_zalloc(btrfs_free_space_bitmap_cachep, GFP_NOFS);
4173 		if (!map) {
4174 			kmem_cache_free(btrfs_free_space_cachep, info);
4175 			return -ENOMEM;
4176 		}
4177 	}
4178 
4179 	spin_lock(&ctl->tree_lock);
4180 	bitmap_info = tree_search_offset(ctl, offset_to_bitmap(ctl, offset),
4181 					 1, 0);
4182 	if (!bitmap_info) {
4183 		info->bitmap = map;
4184 		map = NULL;
4185 		add_new_bitmap(ctl, info, offset);
4186 		bitmap_info = info;
4187 		info = NULL;
4188 	}
4189 
4190 	bytes_added = add_bytes_to_bitmap(ctl, bitmap_info, offset, bytes,
4191 					  trim_state);
4192 
4193 	bytes -= bytes_added;
4194 	offset += bytes_added;
4195 	spin_unlock(&ctl->tree_lock);
4196 
4197 	if (bytes)
4198 		goto again;
4199 
4200 	if (info)
4201 		kmem_cache_free(btrfs_free_space_cachep, info);
4202 	if (map)
4203 		kmem_cache_free(btrfs_free_space_bitmap_cachep, map);
4204 	return 0;
4205 }
4206 
4207 /*
4208  * Checks to see if the given range is in the free space cache.  This is really
4209  * just used to check the absence of space, so if there is free space in the
4210  * range at all we will return 1.
4211  */
test_check_exists(struct btrfs_block_group * cache,u64 offset,u64 bytes)4212 int test_check_exists(struct btrfs_block_group *cache,
4213 		      u64 offset, u64 bytes)
4214 {
4215 	struct btrfs_free_space_ctl *ctl = cache->free_space_ctl;
4216 	struct btrfs_free_space *info;
4217 	int ret = 0;
4218 
4219 	spin_lock(&ctl->tree_lock);
4220 	info = tree_search_offset(ctl, offset, 0, 0);
4221 	if (!info) {
4222 		info = tree_search_offset(ctl, offset_to_bitmap(ctl, offset),
4223 					  1, 0);
4224 		if (!info)
4225 			goto out;
4226 	}
4227 
4228 have_info:
4229 	if (info->bitmap) {
4230 		u64 bit_off, bit_bytes;
4231 		struct rb_node *n;
4232 		struct btrfs_free_space *tmp;
4233 
4234 		bit_off = offset;
4235 		bit_bytes = ctl->unit;
4236 		ret = search_bitmap(ctl, info, &bit_off, &bit_bytes, false);
4237 		if (!ret) {
4238 			if (bit_off == offset) {
4239 				ret = 1;
4240 				goto out;
4241 			} else if (bit_off > offset &&
4242 				   offset + bytes > bit_off) {
4243 				ret = 1;
4244 				goto out;
4245 			}
4246 		}
4247 
4248 		n = rb_prev(&info->offset_index);
4249 		while (n) {
4250 			tmp = rb_entry(n, struct btrfs_free_space,
4251 				       offset_index);
4252 			if (tmp->offset + tmp->bytes < offset)
4253 				break;
4254 			if (offset + bytes < tmp->offset) {
4255 				n = rb_prev(&tmp->offset_index);
4256 				continue;
4257 			}
4258 			info = tmp;
4259 			goto have_info;
4260 		}
4261 
4262 		n = rb_next(&info->offset_index);
4263 		while (n) {
4264 			tmp = rb_entry(n, struct btrfs_free_space,
4265 				       offset_index);
4266 			if (offset + bytes < tmp->offset)
4267 				break;
4268 			if (tmp->offset + tmp->bytes < offset) {
4269 				n = rb_next(&tmp->offset_index);
4270 				continue;
4271 			}
4272 			info = tmp;
4273 			goto have_info;
4274 		}
4275 
4276 		ret = 0;
4277 		goto out;
4278 	}
4279 
4280 	if (info->offset == offset) {
4281 		ret = 1;
4282 		goto out;
4283 	}
4284 
4285 	if (offset > info->offset && offset < info->offset + info->bytes)
4286 		ret = 1;
4287 out:
4288 	spin_unlock(&ctl->tree_lock);
4289 	return ret;
4290 }
4291 #endif /* CONFIG_BTRFS_FS_RUN_SANITY_TESTS */
4292