• Home
  • Line#
  • Scopes#
  • Navigate#
  • Raw
  • Download
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Copyright (C) 2008 Red Hat.  All rights reserved.
4  */
5 
6 #include <linux/pagemap.h>
7 #include <linux/sched.h>
8 #include <linux/sched/signal.h>
9 #include <linux/slab.h>
10 #include <linux/math64.h>
11 #include <linux/ratelimit.h>
12 #include <linux/error-injection.h>
13 #include <linux/sched/mm.h>
14 #include "ctree.h"
15 #include "free-space-cache.h"
16 #include "transaction.h"
17 #include "disk-io.h"
18 #include "extent_io.h"
19 #include "inode-map.h"
20 #include "volumes.h"
21 #include "space-info.h"
22 #include "delalloc-space.h"
23 #include "block-group.h"
24 
25 #define BITS_PER_BITMAP		(PAGE_SIZE * 8UL)
26 #define MAX_CACHE_BYTES_PER_GIG	SZ_32K
27 
28 struct btrfs_trim_range {
29 	u64 start;
30 	u64 bytes;
31 	struct list_head list;
32 };
33 
34 static int link_free_space(struct btrfs_free_space_ctl *ctl,
35 			   struct btrfs_free_space *info);
36 static void unlink_free_space(struct btrfs_free_space_ctl *ctl,
37 			      struct btrfs_free_space *info);
38 static int btrfs_wait_cache_io_root(struct btrfs_root *root,
39 			     struct btrfs_trans_handle *trans,
40 			     struct btrfs_io_ctl *io_ctl,
41 			     struct btrfs_path *path);
42 
__lookup_free_space_inode(struct btrfs_root * root,struct btrfs_path * path,u64 offset)43 static struct inode *__lookup_free_space_inode(struct btrfs_root *root,
44 					       struct btrfs_path *path,
45 					       u64 offset)
46 {
47 	struct btrfs_fs_info *fs_info = root->fs_info;
48 	struct btrfs_key key;
49 	struct btrfs_key location;
50 	struct btrfs_disk_key disk_key;
51 	struct btrfs_free_space_header *header;
52 	struct extent_buffer *leaf;
53 	struct inode *inode = NULL;
54 	unsigned nofs_flag;
55 	int ret;
56 
57 	key.objectid = BTRFS_FREE_SPACE_OBJECTID;
58 	key.offset = offset;
59 	key.type = 0;
60 
61 	ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
62 	if (ret < 0)
63 		return ERR_PTR(ret);
64 	if (ret > 0) {
65 		btrfs_release_path(path);
66 		return ERR_PTR(-ENOENT);
67 	}
68 
69 	leaf = path->nodes[0];
70 	header = btrfs_item_ptr(leaf, path->slots[0],
71 				struct btrfs_free_space_header);
72 	btrfs_free_space_key(leaf, header, &disk_key);
73 	btrfs_disk_key_to_cpu(&location, &disk_key);
74 	btrfs_release_path(path);
75 
76 	/*
77 	 * We are often under a trans handle at this point, so we need to make
78 	 * sure NOFS is set to keep us from deadlocking.
79 	 */
80 	nofs_flag = memalloc_nofs_save();
81 	inode = btrfs_iget_path(fs_info->sb, &location, root, NULL, path);
82 	btrfs_release_path(path);
83 	memalloc_nofs_restore(nofs_flag);
84 	if (IS_ERR(inode))
85 		return inode;
86 
87 	mapping_set_gfp_mask(inode->i_mapping,
88 			mapping_gfp_constraint(inode->i_mapping,
89 			~(__GFP_FS | __GFP_HIGHMEM)));
90 
91 	return inode;
92 }
93 
lookup_free_space_inode(struct btrfs_block_group_cache * block_group,struct btrfs_path * path)94 struct inode *lookup_free_space_inode(
95 		struct btrfs_block_group_cache *block_group,
96 		struct btrfs_path *path)
97 {
98 	struct btrfs_fs_info *fs_info = block_group->fs_info;
99 	struct inode *inode = NULL;
100 	u32 flags = BTRFS_INODE_NODATASUM | BTRFS_INODE_NODATACOW;
101 
102 	spin_lock(&block_group->lock);
103 	if (block_group->inode)
104 		inode = igrab(block_group->inode);
105 	spin_unlock(&block_group->lock);
106 	if (inode)
107 		return inode;
108 
109 	inode = __lookup_free_space_inode(fs_info->tree_root, path,
110 					  block_group->key.objectid);
111 	if (IS_ERR(inode))
112 		return inode;
113 
114 	spin_lock(&block_group->lock);
115 	if (!((BTRFS_I(inode)->flags & flags) == flags)) {
116 		btrfs_info(fs_info, "Old style space inode found, converting.");
117 		BTRFS_I(inode)->flags |= BTRFS_INODE_NODATASUM |
118 			BTRFS_INODE_NODATACOW;
119 		block_group->disk_cache_state = BTRFS_DC_CLEAR;
120 	}
121 
122 	if (!block_group->iref) {
123 		block_group->inode = igrab(inode);
124 		block_group->iref = 1;
125 	}
126 	spin_unlock(&block_group->lock);
127 
128 	return inode;
129 }
130 
__create_free_space_inode(struct btrfs_root * root,struct btrfs_trans_handle * trans,struct btrfs_path * path,u64 ino,u64 offset)131 static int __create_free_space_inode(struct btrfs_root *root,
132 				     struct btrfs_trans_handle *trans,
133 				     struct btrfs_path *path,
134 				     u64 ino, u64 offset)
135 {
136 	struct btrfs_key key;
137 	struct btrfs_disk_key disk_key;
138 	struct btrfs_free_space_header *header;
139 	struct btrfs_inode_item *inode_item;
140 	struct extent_buffer *leaf;
141 	u64 flags = BTRFS_INODE_NOCOMPRESS | BTRFS_INODE_PREALLOC;
142 	int ret;
143 
144 	ret = btrfs_insert_empty_inode(trans, root, path, ino);
145 	if (ret)
146 		return ret;
147 
148 	/* We inline crc's for the free disk space cache */
149 	if (ino != BTRFS_FREE_INO_OBJECTID)
150 		flags |= BTRFS_INODE_NODATASUM | BTRFS_INODE_NODATACOW;
151 
152 	leaf = path->nodes[0];
153 	inode_item = btrfs_item_ptr(leaf, path->slots[0],
154 				    struct btrfs_inode_item);
155 	btrfs_item_key(leaf, &disk_key, path->slots[0]);
156 	memzero_extent_buffer(leaf, (unsigned long)inode_item,
157 			     sizeof(*inode_item));
158 	btrfs_set_inode_generation(leaf, inode_item, trans->transid);
159 	btrfs_set_inode_size(leaf, inode_item, 0);
160 	btrfs_set_inode_nbytes(leaf, inode_item, 0);
161 	btrfs_set_inode_uid(leaf, inode_item, 0);
162 	btrfs_set_inode_gid(leaf, inode_item, 0);
163 	btrfs_set_inode_mode(leaf, inode_item, S_IFREG | 0600);
164 	btrfs_set_inode_flags(leaf, inode_item, flags);
165 	btrfs_set_inode_nlink(leaf, inode_item, 1);
166 	btrfs_set_inode_transid(leaf, inode_item, trans->transid);
167 	btrfs_set_inode_block_group(leaf, inode_item, offset);
168 	btrfs_mark_buffer_dirty(leaf);
169 	btrfs_release_path(path);
170 
171 	key.objectid = BTRFS_FREE_SPACE_OBJECTID;
172 	key.offset = offset;
173 	key.type = 0;
174 	ret = btrfs_insert_empty_item(trans, root, path, &key,
175 				      sizeof(struct btrfs_free_space_header));
176 	if (ret < 0) {
177 		btrfs_release_path(path);
178 		return ret;
179 	}
180 
181 	leaf = path->nodes[0];
182 	header = btrfs_item_ptr(leaf, path->slots[0],
183 				struct btrfs_free_space_header);
184 	memzero_extent_buffer(leaf, (unsigned long)header, sizeof(*header));
185 	btrfs_set_free_space_key(leaf, header, &disk_key);
186 	btrfs_mark_buffer_dirty(leaf);
187 	btrfs_release_path(path);
188 
189 	return 0;
190 }
191 
create_free_space_inode(struct btrfs_trans_handle * trans,struct btrfs_block_group_cache * block_group,struct btrfs_path * path)192 int create_free_space_inode(struct btrfs_trans_handle *trans,
193 			    struct btrfs_block_group_cache *block_group,
194 			    struct btrfs_path *path)
195 {
196 	int ret;
197 	u64 ino;
198 
199 	ret = btrfs_find_free_objectid(trans->fs_info->tree_root, &ino);
200 	if (ret < 0)
201 		return ret;
202 
203 	return __create_free_space_inode(trans->fs_info->tree_root, trans, path,
204 					 ino, block_group->key.objectid);
205 }
206 
btrfs_check_trunc_cache_free_space(struct btrfs_fs_info * fs_info,struct btrfs_block_rsv * rsv)207 int btrfs_check_trunc_cache_free_space(struct btrfs_fs_info *fs_info,
208 				       struct btrfs_block_rsv *rsv)
209 {
210 	u64 needed_bytes;
211 	int ret;
212 
213 	/* 1 for slack space, 1 for updating the inode */
214 	needed_bytes = btrfs_calc_insert_metadata_size(fs_info, 1) +
215 		btrfs_calc_metadata_size(fs_info, 1);
216 
217 	spin_lock(&rsv->lock);
218 	if (rsv->reserved < needed_bytes)
219 		ret = -ENOSPC;
220 	else
221 		ret = 0;
222 	spin_unlock(&rsv->lock);
223 	return ret;
224 }
225 
btrfs_truncate_free_space_cache(struct btrfs_trans_handle * trans,struct btrfs_block_group_cache * block_group,struct inode * inode)226 int btrfs_truncate_free_space_cache(struct btrfs_trans_handle *trans,
227 				    struct btrfs_block_group_cache *block_group,
228 				    struct inode *inode)
229 {
230 	struct btrfs_root *root = BTRFS_I(inode)->root;
231 	int ret = 0;
232 	bool locked = false;
233 
234 	if (block_group) {
235 		struct btrfs_path *path = btrfs_alloc_path();
236 
237 		if (!path) {
238 			ret = -ENOMEM;
239 			goto fail;
240 		}
241 		locked = true;
242 		mutex_lock(&trans->transaction->cache_write_mutex);
243 		if (!list_empty(&block_group->io_list)) {
244 			list_del_init(&block_group->io_list);
245 
246 			btrfs_wait_cache_io(trans, block_group, path);
247 			btrfs_put_block_group(block_group);
248 		}
249 
250 		/*
251 		 * now that we've truncated the cache away, its no longer
252 		 * setup or written
253 		 */
254 		spin_lock(&block_group->lock);
255 		block_group->disk_cache_state = BTRFS_DC_CLEAR;
256 		spin_unlock(&block_group->lock);
257 		btrfs_free_path(path);
258 	}
259 
260 	btrfs_i_size_write(BTRFS_I(inode), 0);
261 	truncate_pagecache(inode, 0);
262 
263 	/*
264 	 * We skip the throttling logic for free space cache inodes, so we don't
265 	 * need to check for -EAGAIN.
266 	 */
267 	ret = btrfs_truncate_inode_items(trans, root, inode,
268 					 0, BTRFS_EXTENT_DATA_KEY);
269 	if (ret)
270 		goto fail;
271 
272 	ret = btrfs_update_inode(trans, root, inode);
273 
274 fail:
275 	if (locked)
276 		mutex_unlock(&trans->transaction->cache_write_mutex);
277 	if (ret)
278 		btrfs_abort_transaction(trans, ret);
279 
280 	return ret;
281 }
282 
readahead_cache(struct inode * inode)283 static void readahead_cache(struct inode *inode)
284 {
285 	struct file_ra_state *ra;
286 	unsigned long last_index;
287 
288 	ra = kzalloc(sizeof(*ra), GFP_NOFS);
289 	if (!ra)
290 		return;
291 
292 	file_ra_state_init(ra, inode->i_mapping);
293 	last_index = (i_size_read(inode) - 1) >> PAGE_SHIFT;
294 
295 	page_cache_sync_readahead(inode->i_mapping, ra, NULL, 0, last_index);
296 
297 	kfree(ra);
298 }
299 
io_ctl_init(struct btrfs_io_ctl * io_ctl,struct inode * inode,int write)300 static int io_ctl_init(struct btrfs_io_ctl *io_ctl, struct inode *inode,
301 		       int write)
302 {
303 	int num_pages;
304 	int check_crcs = 0;
305 
306 	num_pages = DIV_ROUND_UP(i_size_read(inode), PAGE_SIZE);
307 
308 	if (btrfs_ino(BTRFS_I(inode)) != BTRFS_FREE_INO_OBJECTID)
309 		check_crcs = 1;
310 
311 	/* Make sure we can fit our crcs and generation into the first page */
312 	if (write && check_crcs &&
313 	    (num_pages * sizeof(u32) + sizeof(u64)) > PAGE_SIZE)
314 		return -ENOSPC;
315 
316 	memset(io_ctl, 0, sizeof(struct btrfs_io_ctl));
317 
318 	io_ctl->pages = kcalloc(num_pages, sizeof(struct page *), GFP_NOFS);
319 	if (!io_ctl->pages)
320 		return -ENOMEM;
321 
322 	io_ctl->num_pages = num_pages;
323 	io_ctl->fs_info = btrfs_sb(inode->i_sb);
324 	io_ctl->check_crcs = check_crcs;
325 	io_ctl->inode = inode;
326 
327 	return 0;
328 }
329 ALLOW_ERROR_INJECTION(io_ctl_init, ERRNO);
330 
io_ctl_free(struct btrfs_io_ctl * io_ctl)331 static void io_ctl_free(struct btrfs_io_ctl *io_ctl)
332 {
333 	kfree(io_ctl->pages);
334 	io_ctl->pages = NULL;
335 }
336 
io_ctl_unmap_page(struct btrfs_io_ctl * io_ctl)337 static void io_ctl_unmap_page(struct btrfs_io_ctl *io_ctl)
338 {
339 	if (io_ctl->cur) {
340 		io_ctl->cur = NULL;
341 		io_ctl->orig = NULL;
342 	}
343 }
344 
io_ctl_map_page(struct btrfs_io_ctl * io_ctl,int clear)345 static void io_ctl_map_page(struct btrfs_io_ctl *io_ctl, int clear)
346 {
347 	ASSERT(io_ctl->index < io_ctl->num_pages);
348 	io_ctl->page = io_ctl->pages[io_ctl->index++];
349 	io_ctl->cur = page_address(io_ctl->page);
350 	io_ctl->orig = io_ctl->cur;
351 	io_ctl->size = PAGE_SIZE;
352 	if (clear)
353 		clear_page(io_ctl->cur);
354 }
355 
io_ctl_drop_pages(struct btrfs_io_ctl * io_ctl)356 static void io_ctl_drop_pages(struct btrfs_io_ctl *io_ctl)
357 {
358 	int i;
359 
360 	io_ctl_unmap_page(io_ctl);
361 
362 	for (i = 0; i < io_ctl->num_pages; i++) {
363 		if (io_ctl->pages[i]) {
364 			ClearPageChecked(io_ctl->pages[i]);
365 			unlock_page(io_ctl->pages[i]);
366 			put_page(io_ctl->pages[i]);
367 		}
368 	}
369 }
370 
io_ctl_prepare_pages(struct btrfs_io_ctl * io_ctl,struct inode * inode,int uptodate)371 static int io_ctl_prepare_pages(struct btrfs_io_ctl *io_ctl, struct inode *inode,
372 				int uptodate)
373 {
374 	struct page *page;
375 	gfp_t mask = btrfs_alloc_write_mask(inode->i_mapping);
376 	int i;
377 
378 	for (i = 0; i < io_ctl->num_pages; i++) {
379 		page = find_or_create_page(inode->i_mapping, i, mask);
380 		if (!page) {
381 			io_ctl_drop_pages(io_ctl);
382 			return -ENOMEM;
383 		}
384 		io_ctl->pages[i] = page;
385 		if (uptodate && !PageUptodate(page)) {
386 			btrfs_readpage(NULL, page);
387 			lock_page(page);
388 			if (page->mapping != inode->i_mapping) {
389 				btrfs_err(BTRFS_I(inode)->root->fs_info,
390 					  "free space cache page truncated");
391 				io_ctl_drop_pages(io_ctl);
392 				return -EIO;
393 			}
394 			if (!PageUptodate(page)) {
395 				btrfs_err(BTRFS_I(inode)->root->fs_info,
396 					   "error reading free space cache");
397 				io_ctl_drop_pages(io_ctl);
398 				return -EIO;
399 			}
400 		}
401 	}
402 
403 	for (i = 0; i < io_ctl->num_pages; i++) {
404 		clear_page_dirty_for_io(io_ctl->pages[i]);
405 		set_page_extent_mapped(io_ctl->pages[i]);
406 	}
407 
408 	return 0;
409 }
410 
io_ctl_set_generation(struct btrfs_io_ctl * io_ctl,u64 generation)411 static void io_ctl_set_generation(struct btrfs_io_ctl *io_ctl, u64 generation)
412 {
413 	__le64 *val;
414 
415 	io_ctl_map_page(io_ctl, 1);
416 
417 	/*
418 	 * Skip the csum areas.  If we don't check crcs then we just have a
419 	 * 64bit chunk at the front of the first page.
420 	 */
421 	if (io_ctl->check_crcs) {
422 		io_ctl->cur += (sizeof(u32) * io_ctl->num_pages);
423 		io_ctl->size -= sizeof(u64) + (sizeof(u32) * io_ctl->num_pages);
424 	} else {
425 		io_ctl->cur += sizeof(u64);
426 		io_ctl->size -= sizeof(u64) * 2;
427 	}
428 
429 	val = io_ctl->cur;
430 	*val = cpu_to_le64(generation);
431 	io_ctl->cur += sizeof(u64);
432 }
433 
io_ctl_check_generation(struct btrfs_io_ctl * io_ctl,u64 generation)434 static int io_ctl_check_generation(struct btrfs_io_ctl *io_ctl, u64 generation)
435 {
436 	__le64 *gen;
437 
438 	/*
439 	 * Skip the crc area.  If we don't check crcs then we just have a 64bit
440 	 * chunk at the front of the first page.
441 	 */
442 	if (io_ctl->check_crcs) {
443 		io_ctl->cur += sizeof(u32) * io_ctl->num_pages;
444 		io_ctl->size -= sizeof(u64) +
445 			(sizeof(u32) * io_ctl->num_pages);
446 	} else {
447 		io_ctl->cur += sizeof(u64);
448 		io_ctl->size -= sizeof(u64) * 2;
449 	}
450 
451 	gen = io_ctl->cur;
452 	if (le64_to_cpu(*gen) != generation) {
453 		btrfs_err_rl(io_ctl->fs_info,
454 			"space cache generation (%llu) does not match inode (%llu)",
455 				*gen, generation);
456 		io_ctl_unmap_page(io_ctl);
457 		return -EIO;
458 	}
459 	io_ctl->cur += sizeof(u64);
460 	return 0;
461 }
462 
io_ctl_set_crc(struct btrfs_io_ctl * io_ctl,int index)463 static void io_ctl_set_crc(struct btrfs_io_ctl *io_ctl, int index)
464 {
465 	u32 *tmp;
466 	u32 crc = ~(u32)0;
467 	unsigned offset = 0;
468 
469 	if (!io_ctl->check_crcs) {
470 		io_ctl_unmap_page(io_ctl);
471 		return;
472 	}
473 
474 	if (index == 0)
475 		offset = sizeof(u32) * io_ctl->num_pages;
476 
477 	crc = btrfs_crc32c(crc, io_ctl->orig + offset, PAGE_SIZE - offset);
478 	btrfs_crc32c_final(crc, (u8 *)&crc);
479 	io_ctl_unmap_page(io_ctl);
480 	tmp = page_address(io_ctl->pages[0]);
481 	tmp += index;
482 	*tmp = crc;
483 }
484 
io_ctl_check_crc(struct btrfs_io_ctl * io_ctl,int index)485 static int io_ctl_check_crc(struct btrfs_io_ctl *io_ctl, int index)
486 {
487 	u32 *tmp, val;
488 	u32 crc = ~(u32)0;
489 	unsigned offset = 0;
490 
491 	if (!io_ctl->check_crcs) {
492 		io_ctl_map_page(io_ctl, 0);
493 		return 0;
494 	}
495 
496 	if (index == 0)
497 		offset = sizeof(u32) * io_ctl->num_pages;
498 
499 	tmp = page_address(io_ctl->pages[0]);
500 	tmp += index;
501 	val = *tmp;
502 
503 	io_ctl_map_page(io_ctl, 0);
504 	crc = btrfs_crc32c(crc, io_ctl->orig + offset, PAGE_SIZE - offset);
505 	btrfs_crc32c_final(crc, (u8 *)&crc);
506 	if (val != crc) {
507 		btrfs_err_rl(io_ctl->fs_info,
508 			"csum mismatch on free space cache");
509 		io_ctl_unmap_page(io_ctl);
510 		return -EIO;
511 	}
512 
513 	return 0;
514 }
515 
io_ctl_add_entry(struct btrfs_io_ctl * io_ctl,u64 offset,u64 bytes,void * bitmap)516 static int io_ctl_add_entry(struct btrfs_io_ctl *io_ctl, u64 offset, u64 bytes,
517 			    void *bitmap)
518 {
519 	struct btrfs_free_space_entry *entry;
520 
521 	if (!io_ctl->cur)
522 		return -ENOSPC;
523 
524 	entry = io_ctl->cur;
525 	entry->offset = cpu_to_le64(offset);
526 	entry->bytes = cpu_to_le64(bytes);
527 	entry->type = (bitmap) ? BTRFS_FREE_SPACE_BITMAP :
528 		BTRFS_FREE_SPACE_EXTENT;
529 	io_ctl->cur += sizeof(struct btrfs_free_space_entry);
530 	io_ctl->size -= sizeof(struct btrfs_free_space_entry);
531 
532 	if (io_ctl->size >= sizeof(struct btrfs_free_space_entry))
533 		return 0;
534 
535 	io_ctl_set_crc(io_ctl, io_ctl->index - 1);
536 
537 	/* No more pages to map */
538 	if (io_ctl->index >= io_ctl->num_pages)
539 		return 0;
540 
541 	/* map the next page */
542 	io_ctl_map_page(io_ctl, 1);
543 	return 0;
544 }
545 
io_ctl_add_bitmap(struct btrfs_io_ctl * io_ctl,void * bitmap)546 static int io_ctl_add_bitmap(struct btrfs_io_ctl *io_ctl, void *bitmap)
547 {
548 	if (!io_ctl->cur)
549 		return -ENOSPC;
550 
551 	/*
552 	 * If we aren't at the start of the current page, unmap this one and
553 	 * map the next one if there is any left.
554 	 */
555 	if (io_ctl->cur != io_ctl->orig) {
556 		io_ctl_set_crc(io_ctl, io_ctl->index - 1);
557 		if (io_ctl->index >= io_ctl->num_pages)
558 			return -ENOSPC;
559 		io_ctl_map_page(io_ctl, 0);
560 	}
561 
562 	copy_page(io_ctl->cur, bitmap);
563 	io_ctl_set_crc(io_ctl, io_ctl->index - 1);
564 	if (io_ctl->index < io_ctl->num_pages)
565 		io_ctl_map_page(io_ctl, 0);
566 	return 0;
567 }
568 
io_ctl_zero_remaining_pages(struct btrfs_io_ctl * io_ctl)569 static void io_ctl_zero_remaining_pages(struct btrfs_io_ctl *io_ctl)
570 {
571 	/*
572 	 * If we're not on the boundary we know we've modified the page and we
573 	 * need to crc the page.
574 	 */
575 	if (io_ctl->cur != io_ctl->orig)
576 		io_ctl_set_crc(io_ctl, io_ctl->index - 1);
577 	else
578 		io_ctl_unmap_page(io_ctl);
579 
580 	while (io_ctl->index < io_ctl->num_pages) {
581 		io_ctl_map_page(io_ctl, 1);
582 		io_ctl_set_crc(io_ctl, io_ctl->index - 1);
583 	}
584 }
585 
io_ctl_read_entry(struct btrfs_io_ctl * io_ctl,struct btrfs_free_space * entry,u8 * type)586 static int io_ctl_read_entry(struct btrfs_io_ctl *io_ctl,
587 			    struct btrfs_free_space *entry, u8 *type)
588 {
589 	struct btrfs_free_space_entry *e;
590 	int ret;
591 
592 	if (!io_ctl->cur) {
593 		ret = io_ctl_check_crc(io_ctl, io_ctl->index);
594 		if (ret)
595 			return ret;
596 	}
597 
598 	e = io_ctl->cur;
599 	entry->offset = le64_to_cpu(e->offset);
600 	entry->bytes = le64_to_cpu(e->bytes);
601 	*type = e->type;
602 	io_ctl->cur += sizeof(struct btrfs_free_space_entry);
603 	io_ctl->size -= sizeof(struct btrfs_free_space_entry);
604 
605 	if (io_ctl->size >= sizeof(struct btrfs_free_space_entry))
606 		return 0;
607 
608 	io_ctl_unmap_page(io_ctl);
609 
610 	return 0;
611 }
612 
io_ctl_read_bitmap(struct btrfs_io_ctl * io_ctl,struct btrfs_free_space * entry)613 static int io_ctl_read_bitmap(struct btrfs_io_ctl *io_ctl,
614 			      struct btrfs_free_space *entry)
615 {
616 	int ret;
617 
618 	ret = io_ctl_check_crc(io_ctl, io_ctl->index);
619 	if (ret)
620 		return ret;
621 
622 	copy_page(entry->bitmap, io_ctl->cur);
623 	io_ctl_unmap_page(io_ctl);
624 
625 	return 0;
626 }
627 
628 /*
629  * Since we attach pinned extents after the fact we can have contiguous sections
630  * of free space that are split up in entries.  This poses a problem with the
631  * tree logging stuff since it could have allocated across what appears to be 2
632  * entries since we would have merged the entries when adding the pinned extents
633  * back to the free space cache.  So run through the space cache that we just
634  * loaded and merge contiguous entries.  This will make the log replay stuff not
635  * blow up and it will make for nicer allocator behavior.
636  */
merge_space_tree(struct btrfs_free_space_ctl * ctl)637 static void merge_space_tree(struct btrfs_free_space_ctl *ctl)
638 {
639 	struct btrfs_free_space *e, *prev = NULL;
640 	struct rb_node *n;
641 
642 again:
643 	spin_lock(&ctl->tree_lock);
644 	for (n = rb_first(&ctl->free_space_offset); n; n = rb_next(n)) {
645 		e = rb_entry(n, struct btrfs_free_space, offset_index);
646 		if (!prev)
647 			goto next;
648 		if (e->bitmap || prev->bitmap)
649 			goto next;
650 		if (prev->offset + prev->bytes == e->offset) {
651 			unlink_free_space(ctl, prev);
652 			unlink_free_space(ctl, e);
653 			prev->bytes += e->bytes;
654 			kmem_cache_free(btrfs_free_space_cachep, e);
655 			link_free_space(ctl, prev);
656 			prev = NULL;
657 			spin_unlock(&ctl->tree_lock);
658 			goto again;
659 		}
660 next:
661 		prev = e;
662 	}
663 	spin_unlock(&ctl->tree_lock);
664 }
665 
__load_free_space_cache(struct btrfs_root * root,struct inode * inode,struct btrfs_free_space_ctl * ctl,struct btrfs_path * path,u64 offset)666 static int __load_free_space_cache(struct btrfs_root *root, struct inode *inode,
667 				   struct btrfs_free_space_ctl *ctl,
668 				   struct btrfs_path *path, u64 offset)
669 {
670 	struct btrfs_fs_info *fs_info = root->fs_info;
671 	struct btrfs_free_space_header *header;
672 	struct extent_buffer *leaf;
673 	struct btrfs_io_ctl io_ctl;
674 	struct btrfs_key key;
675 	struct btrfs_free_space *e, *n;
676 	LIST_HEAD(bitmaps);
677 	u64 num_entries;
678 	u64 num_bitmaps;
679 	u64 generation;
680 	u8 type;
681 	int ret = 0;
682 
683 	/* Nothing in the space cache, goodbye */
684 	if (!i_size_read(inode))
685 		return 0;
686 
687 	key.objectid = BTRFS_FREE_SPACE_OBJECTID;
688 	key.offset = offset;
689 	key.type = 0;
690 
691 	ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
692 	if (ret < 0)
693 		return 0;
694 	else if (ret > 0) {
695 		btrfs_release_path(path);
696 		return 0;
697 	}
698 
699 	ret = -1;
700 
701 	leaf = path->nodes[0];
702 	header = btrfs_item_ptr(leaf, path->slots[0],
703 				struct btrfs_free_space_header);
704 	num_entries = btrfs_free_space_entries(leaf, header);
705 	num_bitmaps = btrfs_free_space_bitmaps(leaf, header);
706 	generation = btrfs_free_space_generation(leaf, header);
707 	btrfs_release_path(path);
708 
709 	if (!BTRFS_I(inode)->generation) {
710 		btrfs_info(fs_info,
711 			   "the free space cache file (%llu) is invalid, skip it",
712 			   offset);
713 		return 0;
714 	}
715 
716 	if (BTRFS_I(inode)->generation != generation) {
717 		btrfs_err(fs_info,
718 			  "free space inode generation (%llu) did not match free space cache generation (%llu)",
719 			  BTRFS_I(inode)->generation, generation);
720 		return 0;
721 	}
722 
723 	if (!num_entries)
724 		return 0;
725 
726 	ret = io_ctl_init(&io_ctl, inode, 0);
727 	if (ret)
728 		return ret;
729 
730 	readahead_cache(inode);
731 
732 	ret = io_ctl_prepare_pages(&io_ctl, inode, 1);
733 	if (ret)
734 		goto out;
735 
736 	ret = io_ctl_check_crc(&io_ctl, 0);
737 	if (ret)
738 		goto free_cache;
739 
740 	ret = io_ctl_check_generation(&io_ctl, generation);
741 	if (ret)
742 		goto free_cache;
743 
744 	while (num_entries) {
745 		e = kmem_cache_zalloc(btrfs_free_space_cachep,
746 				      GFP_NOFS);
747 		if (!e) {
748 			ret = -ENOMEM;
749 			goto free_cache;
750 		}
751 
752 		ret = io_ctl_read_entry(&io_ctl, e, &type);
753 		if (ret) {
754 			kmem_cache_free(btrfs_free_space_cachep, e);
755 			goto free_cache;
756 		}
757 
758 		if (!e->bytes) {
759 			ret = -1;
760 			kmem_cache_free(btrfs_free_space_cachep, e);
761 			goto free_cache;
762 		}
763 
764 		if (type == BTRFS_FREE_SPACE_EXTENT) {
765 			spin_lock(&ctl->tree_lock);
766 			ret = link_free_space(ctl, e);
767 			spin_unlock(&ctl->tree_lock);
768 			if (ret) {
769 				btrfs_err(fs_info,
770 					"Duplicate entries in free space cache, dumping");
771 				kmem_cache_free(btrfs_free_space_cachep, e);
772 				goto free_cache;
773 			}
774 		} else {
775 			ASSERT(num_bitmaps);
776 			num_bitmaps--;
777 			e->bitmap = kmem_cache_zalloc(
778 					btrfs_free_space_bitmap_cachep, GFP_NOFS);
779 			if (!e->bitmap) {
780 				ret = -ENOMEM;
781 				kmem_cache_free(
782 					btrfs_free_space_cachep, e);
783 				goto free_cache;
784 			}
785 			spin_lock(&ctl->tree_lock);
786 			ret = link_free_space(ctl, e);
787 			if (ret) {
788 				spin_unlock(&ctl->tree_lock);
789 				btrfs_err(fs_info,
790 					"Duplicate entries in free space cache, dumping");
791 				kmem_cache_free(btrfs_free_space_cachep, e);
792 				goto free_cache;
793 			}
794 			ctl->total_bitmaps++;
795 			ctl->op->recalc_thresholds(ctl);
796 			spin_unlock(&ctl->tree_lock);
797 			list_add_tail(&e->list, &bitmaps);
798 		}
799 
800 		num_entries--;
801 	}
802 
803 	io_ctl_unmap_page(&io_ctl);
804 
805 	/*
806 	 * We add the bitmaps at the end of the entries in order that
807 	 * the bitmap entries are added to the cache.
808 	 */
809 	list_for_each_entry_safe(e, n, &bitmaps, list) {
810 		list_del_init(&e->list);
811 		ret = io_ctl_read_bitmap(&io_ctl, e);
812 		if (ret)
813 			goto free_cache;
814 	}
815 
816 	io_ctl_drop_pages(&io_ctl);
817 	merge_space_tree(ctl);
818 	ret = 1;
819 out:
820 	io_ctl_free(&io_ctl);
821 	return ret;
822 free_cache:
823 	io_ctl_drop_pages(&io_ctl);
824 	__btrfs_remove_free_space_cache(ctl);
825 	goto out;
826 }
827 
load_free_space_cache(struct btrfs_block_group_cache * block_group)828 int load_free_space_cache(struct btrfs_block_group_cache *block_group)
829 {
830 	struct btrfs_fs_info *fs_info = block_group->fs_info;
831 	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
832 	struct inode *inode;
833 	struct btrfs_path *path;
834 	int ret = 0;
835 	bool matched;
836 	u64 used = btrfs_block_group_used(&block_group->item);
837 
838 	/*
839 	 * If this block group has been marked to be cleared for one reason or
840 	 * another then we can't trust the on disk cache, so just return.
841 	 */
842 	spin_lock(&block_group->lock);
843 	if (block_group->disk_cache_state != BTRFS_DC_WRITTEN) {
844 		spin_unlock(&block_group->lock);
845 		return 0;
846 	}
847 	spin_unlock(&block_group->lock);
848 
849 	path = btrfs_alloc_path();
850 	if (!path)
851 		return 0;
852 	path->search_commit_root = 1;
853 	path->skip_locking = 1;
854 
855 	/*
856 	 * We must pass a path with search_commit_root set to btrfs_iget in
857 	 * order to avoid a deadlock when allocating extents for the tree root.
858 	 *
859 	 * When we are COWing an extent buffer from the tree root, when looking
860 	 * for a free extent, at extent-tree.c:find_free_extent(), we can find
861 	 * block group without its free space cache loaded. When we find one
862 	 * we must load its space cache which requires reading its free space
863 	 * cache's inode item from the root tree. If this inode item is located
864 	 * in the same leaf that we started COWing before, then we end up in
865 	 * deadlock on the extent buffer (trying to read lock it when we
866 	 * previously write locked it).
867 	 *
868 	 * It's safe to read the inode item using the commit root because
869 	 * block groups, once loaded, stay in memory forever (until they are
870 	 * removed) as well as their space caches once loaded. New block groups
871 	 * once created get their ->cached field set to BTRFS_CACHE_FINISHED so
872 	 * we will never try to read their inode item while the fs is mounted.
873 	 */
874 	inode = lookup_free_space_inode(block_group, path);
875 	if (IS_ERR(inode)) {
876 		btrfs_free_path(path);
877 		return 0;
878 	}
879 
880 	/* We may have converted the inode and made the cache invalid. */
881 	spin_lock(&block_group->lock);
882 	if (block_group->disk_cache_state != BTRFS_DC_WRITTEN) {
883 		spin_unlock(&block_group->lock);
884 		btrfs_free_path(path);
885 		goto out;
886 	}
887 	spin_unlock(&block_group->lock);
888 
889 	ret = __load_free_space_cache(fs_info->tree_root, inode, ctl,
890 				      path, block_group->key.objectid);
891 	btrfs_free_path(path);
892 	if (ret <= 0)
893 		goto out;
894 
895 	spin_lock(&ctl->tree_lock);
896 	matched = (ctl->free_space == (block_group->key.offset - used -
897 				       block_group->bytes_super));
898 	spin_unlock(&ctl->tree_lock);
899 
900 	if (!matched) {
901 		__btrfs_remove_free_space_cache(ctl);
902 		btrfs_warn(fs_info,
903 			   "block group %llu has wrong amount of free space",
904 			   block_group->key.objectid);
905 		ret = -1;
906 	}
907 out:
908 	if (ret < 0) {
909 		/* This cache is bogus, make sure it gets cleared */
910 		spin_lock(&block_group->lock);
911 		block_group->disk_cache_state = BTRFS_DC_CLEAR;
912 		spin_unlock(&block_group->lock);
913 		ret = 0;
914 
915 		btrfs_warn(fs_info,
916 			   "failed to load free space cache for block group %llu, rebuilding it now",
917 			   block_group->key.objectid);
918 	}
919 
920 	iput(inode);
921 	return ret;
922 }
923 
924 static noinline_for_stack
write_cache_extent_entries(struct btrfs_io_ctl * io_ctl,struct btrfs_free_space_ctl * ctl,struct btrfs_block_group_cache * block_group,int * entries,int * bitmaps,struct list_head * bitmap_list)925 int write_cache_extent_entries(struct btrfs_io_ctl *io_ctl,
926 			      struct btrfs_free_space_ctl *ctl,
927 			      struct btrfs_block_group_cache *block_group,
928 			      int *entries, int *bitmaps,
929 			      struct list_head *bitmap_list)
930 {
931 	int ret;
932 	struct btrfs_free_cluster *cluster = NULL;
933 	struct btrfs_free_cluster *cluster_locked = NULL;
934 	struct rb_node *node = rb_first(&ctl->free_space_offset);
935 	struct btrfs_trim_range *trim_entry;
936 
937 	/* Get the cluster for this block_group if it exists */
938 	if (block_group && !list_empty(&block_group->cluster_list)) {
939 		cluster = list_entry(block_group->cluster_list.next,
940 				     struct btrfs_free_cluster,
941 				     block_group_list);
942 	}
943 
944 	if (!node && cluster) {
945 		cluster_locked = cluster;
946 		spin_lock(&cluster_locked->lock);
947 		node = rb_first(&cluster->root);
948 		cluster = NULL;
949 	}
950 
951 	/* Write out the extent entries */
952 	while (node) {
953 		struct btrfs_free_space *e;
954 
955 		e = rb_entry(node, struct btrfs_free_space, offset_index);
956 		*entries += 1;
957 
958 		ret = io_ctl_add_entry(io_ctl, e->offset, e->bytes,
959 				       e->bitmap);
960 		if (ret)
961 			goto fail;
962 
963 		if (e->bitmap) {
964 			list_add_tail(&e->list, bitmap_list);
965 			*bitmaps += 1;
966 		}
967 		node = rb_next(node);
968 		if (!node && cluster) {
969 			node = rb_first(&cluster->root);
970 			cluster_locked = cluster;
971 			spin_lock(&cluster_locked->lock);
972 			cluster = NULL;
973 		}
974 	}
975 	if (cluster_locked) {
976 		spin_unlock(&cluster_locked->lock);
977 		cluster_locked = NULL;
978 	}
979 
980 	/*
981 	 * Make sure we don't miss any range that was removed from our rbtree
982 	 * because trimming is running. Otherwise after a umount+mount (or crash
983 	 * after committing the transaction) we would leak free space and get
984 	 * an inconsistent free space cache report from fsck.
985 	 */
986 	list_for_each_entry(trim_entry, &ctl->trimming_ranges, list) {
987 		ret = io_ctl_add_entry(io_ctl, trim_entry->start,
988 				       trim_entry->bytes, NULL);
989 		if (ret)
990 			goto fail;
991 		*entries += 1;
992 	}
993 
994 	return 0;
995 fail:
996 	if (cluster_locked)
997 		spin_unlock(&cluster_locked->lock);
998 	return -ENOSPC;
999 }
1000 
1001 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)1002 update_cache_item(struct btrfs_trans_handle *trans,
1003 		  struct btrfs_root *root,
1004 		  struct inode *inode,
1005 		  struct btrfs_path *path, u64 offset,
1006 		  int entries, int bitmaps)
1007 {
1008 	struct btrfs_key key;
1009 	struct btrfs_free_space_header *header;
1010 	struct extent_buffer *leaf;
1011 	int ret;
1012 
1013 	key.objectid = BTRFS_FREE_SPACE_OBJECTID;
1014 	key.offset = offset;
1015 	key.type = 0;
1016 
1017 	ret = btrfs_search_slot(trans, root, &key, path, 0, 1);
1018 	if (ret < 0) {
1019 		clear_extent_bit(&BTRFS_I(inode)->io_tree, 0, inode->i_size - 1,
1020 				 EXTENT_DELALLOC, 0, 0, NULL);
1021 		goto fail;
1022 	}
1023 	leaf = path->nodes[0];
1024 	if (ret > 0) {
1025 		struct btrfs_key found_key;
1026 		ASSERT(path->slots[0]);
1027 		path->slots[0]--;
1028 		btrfs_item_key_to_cpu(leaf, &found_key, path->slots[0]);
1029 		if (found_key.objectid != BTRFS_FREE_SPACE_OBJECTID ||
1030 		    found_key.offset != offset) {
1031 			clear_extent_bit(&BTRFS_I(inode)->io_tree, 0,
1032 					 inode->i_size - 1, EXTENT_DELALLOC, 0,
1033 					 0, NULL);
1034 			btrfs_release_path(path);
1035 			goto fail;
1036 		}
1037 	}
1038 
1039 	BTRFS_I(inode)->generation = trans->transid;
1040 	header = btrfs_item_ptr(leaf, path->slots[0],
1041 				struct btrfs_free_space_header);
1042 	btrfs_set_free_space_entries(leaf, header, entries);
1043 	btrfs_set_free_space_bitmaps(leaf, header, bitmaps);
1044 	btrfs_set_free_space_generation(leaf, header, trans->transid);
1045 	btrfs_mark_buffer_dirty(leaf);
1046 	btrfs_release_path(path);
1047 
1048 	return 0;
1049 
1050 fail:
1051 	return -1;
1052 }
1053 
write_pinned_extent_entries(struct btrfs_block_group_cache * block_group,struct btrfs_io_ctl * io_ctl,int * entries)1054 static noinline_for_stack int write_pinned_extent_entries(
1055 			    struct btrfs_block_group_cache *block_group,
1056 			    struct btrfs_io_ctl *io_ctl,
1057 			    int *entries)
1058 {
1059 	u64 start, extent_start, extent_end, len;
1060 	struct extent_io_tree *unpin = NULL;
1061 	int ret;
1062 
1063 	if (!block_group)
1064 		return 0;
1065 
1066 	/*
1067 	 * We want to add any pinned extents to our free space cache
1068 	 * so we don't leak the space
1069 	 *
1070 	 * We shouldn't have switched the pinned extents yet so this is the
1071 	 * right one
1072 	 */
1073 	unpin = block_group->fs_info->pinned_extents;
1074 
1075 	start = block_group->key.objectid;
1076 
1077 	while (start < block_group->key.objectid + block_group->key.offset) {
1078 		ret = find_first_extent_bit(unpin, start,
1079 					    &extent_start, &extent_end,
1080 					    EXTENT_DIRTY, NULL);
1081 		if (ret)
1082 			return 0;
1083 
1084 		/* This pinned extent is out of our range */
1085 		if (extent_start >= block_group->key.objectid +
1086 		    block_group->key.offset)
1087 			return 0;
1088 
1089 		extent_start = max(extent_start, start);
1090 		extent_end = min(block_group->key.objectid +
1091 				 block_group->key.offset, extent_end + 1);
1092 		len = extent_end - extent_start;
1093 
1094 		*entries += 1;
1095 		ret = io_ctl_add_entry(io_ctl, extent_start, len, NULL);
1096 		if (ret)
1097 			return -ENOSPC;
1098 
1099 		start = extent_end;
1100 	}
1101 
1102 	return 0;
1103 }
1104 
1105 static noinline_for_stack int
write_bitmap_entries(struct btrfs_io_ctl * io_ctl,struct list_head * bitmap_list)1106 write_bitmap_entries(struct btrfs_io_ctl *io_ctl, struct list_head *bitmap_list)
1107 {
1108 	struct btrfs_free_space *entry, *next;
1109 	int ret;
1110 
1111 	/* Write out the bitmaps */
1112 	list_for_each_entry_safe(entry, next, bitmap_list, list) {
1113 		ret = io_ctl_add_bitmap(io_ctl, entry->bitmap);
1114 		if (ret)
1115 			return -ENOSPC;
1116 		list_del_init(&entry->list);
1117 	}
1118 
1119 	return 0;
1120 }
1121 
flush_dirty_cache(struct inode * inode)1122 static int flush_dirty_cache(struct inode *inode)
1123 {
1124 	int ret;
1125 
1126 	ret = btrfs_wait_ordered_range(inode, 0, (u64)-1);
1127 	if (ret)
1128 		clear_extent_bit(&BTRFS_I(inode)->io_tree, 0, inode->i_size - 1,
1129 				 EXTENT_DELALLOC, 0, 0, NULL);
1130 
1131 	return ret;
1132 }
1133 
1134 static void noinline_for_stack
cleanup_bitmap_list(struct list_head * bitmap_list)1135 cleanup_bitmap_list(struct list_head *bitmap_list)
1136 {
1137 	struct btrfs_free_space *entry, *next;
1138 
1139 	list_for_each_entry_safe(entry, next, bitmap_list, list)
1140 		list_del_init(&entry->list);
1141 }
1142 
1143 static void noinline_for_stack
cleanup_write_cache_enospc(struct inode * inode,struct btrfs_io_ctl * io_ctl,struct extent_state ** cached_state)1144 cleanup_write_cache_enospc(struct inode *inode,
1145 			   struct btrfs_io_ctl *io_ctl,
1146 			   struct extent_state **cached_state)
1147 {
1148 	io_ctl_drop_pages(io_ctl);
1149 	unlock_extent_cached(&BTRFS_I(inode)->io_tree, 0,
1150 			     i_size_read(inode) - 1, cached_state);
1151 }
1152 
__btrfs_wait_cache_io(struct btrfs_root * root,struct btrfs_trans_handle * trans,struct btrfs_block_group_cache * block_group,struct btrfs_io_ctl * io_ctl,struct btrfs_path * path,u64 offset)1153 static int __btrfs_wait_cache_io(struct btrfs_root *root,
1154 				 struct btrfs_trans_handle *trans,
1155 				 struct btrfs_block_group_cache *block_group,
1156 				 struct btrfs_io_ctl *io_ctl,
1157 				 struct btrfs_path *path, u64 offset)
1158 {
1159 	int ret;
1160 	struct inode *inode = io_ctl->inode;
1161 
1162 	if (!inode)
1163 		return 0;
1164 
1165 	/* Flush the dirty pages in the cache file. */
1166 	ret = flush_dirty_cache(inode);
1167 	if (ret)
1168 		goto out;
1169 
1170 	/* Update the cache item to tell everyone this cache file is valid. */
1171 	ret = update_cache_item(trans, root, inode, path, offset,
1172 				io_ctl->entries, io_ctl->bitmaps);
1173 out:
1174 	if (ret) {
1175 		invalidate_inode_pages2(inode->i_mapping);
1176 		BTRFS_I(inode)->generation = 0;
1177 		if (block_group) {
1178 #ifdef DEBUG
1179 			btrfs_err(root->fs_info,
1180 				  "failed to write free space cache for block group %llu",
1181 				  block_group->key.objectid);
1182 #endif
1183 		}
1184 	}
1185 	btrfs_update_inode(trans, root, inode);
1186 
1187 	if (block_group) {
1188 		/* the dirty list is protected by the dirty_bgs_lock */
1189 		spin_lock(&trans->transaction->dirty_bgs_lock);
1190 
1191 		/* the disk_cache_state is protected by the block group lock */
1192 		spin_lock(&block_group->lock);
1193 
1194 		/*
1195 		 * only mark this as written if we didn't get put back on
1196 		 * the dirty list while waiting for IO.   Otherwise our
1197 		 * cache state won't be right, and we won't get written again
1198 		 */
1199 		if (!ret && list_empty(&block_group->dirty_list))
1200 			block_group->disk_cache_state = BTRFS_DC_WRITTEN;
1201 		else if (ret)
1202 			block_group->disk_cache_state = BTRFS_DC_ERROR;
1203 
1204 		spin_unlock(&block_group->lock);
1205 		spin_unlock(&trans->transaction->dirty_bgs_lock);
1206 		io_ctl->inode = NULL;
1207 		iput(inode);
1208 	}
1209 
1210 	return ret;
1211 
1212 }
1213 
btrfs_wait_cache_io_root(struct btrfs_root * root,struct btrfs_trans_handle * trans,struct btrfs_io_ctl * io_ctl,struct btrfs_path * path)1214 static int btrfs_wait_cache_io_root(struct btrfs_root *root,
1215 				    struct btrfs_trans_handle *trans,
1216 				    struct btrfs_io_ctl *io_ctl,
1217 				    struct btrfs_path *path)
1218 {
1219 	return __btrfs_wait_cache_io(root, trans, NULL, io_ctl, path, 0);
1220 }
1221 
btrfs_wait_cache_io(struct btrfs_trans_handle * trans,struct btrfs_block_group_cache * block_group,struct btrfs_path * path)1222 int btrfs_wait_cache_io(struct btrfs_trans_handle *trans,
1223 			struct btrfs_block_group_cache *block_group,
1224 			struct btrfs_path *path)
1225 {
1226 	return __btrfs_wait_cache_io(block_group->fs_info->tree_root, trans,
1227 				     block_group, &block_group->io_ctl,
1228 				     path, block_group->key.objectid);
1229 }
1230 
1231 /**
1232  * __btrfs_write_out_cache - write out cached info to an inode
1233  * @root - the root the inode belongs to
1234  * @ctl - the free space cache we are going to write out
1235  * @block_group - the block_group for this cache if it belongs to a block_group
1236  * @trans - the trans handle
1237  *
1238  * This function writes out a free space cache struct to disk for quick recovery
1239  * on mount.  This will return 0 if it was successful in writing the cache out,
1240  * or an errno if it was not.
1241  */
__btrfs_write_out_cache(struct btrfs_root * root,struct inode * inode,struct btrfs_free_space_ctl * ctl,struct btrfs_block_group_cache * block_group,struct btrfs_io_ctl * io_ctl,struct btrfs_trans_handle * trans)1242 static int __btrfs_write_out_cache(struct btrfs_root *root, struct inode *inode,
1243 				   struct btrfs_free_space_ctl *ctl,
1244 				   struct btrfs_block_group_cache *block_group,
1245 				   struct btrfs_io_ctl *io_ctl,
1246 				   struct btrfs_trans_handle *trans)
1247 {
1248 	struct extent_state *cached_state = NULL;
1249 	LIST_HEAD(bitmap_list);
1250 	int entries = 0;
1251 	int bitmaps = 0;
1252 	int ret;
1253 	int must_iput = 0;
1254 
1255 	if (!i_size_read(inode))
1256 		return -EIO;
1257 
1258 	WARN_ON(io_ctl->pages);
1259 	ret = io_ctl_init(io_ctl, inode, 1);
1260 	if (ret)
1261 		return ret;
1262 
1263 	if (block_group && (block_group->flags & BTRFS_BLOCK_GROUP_DATA)) {
1264 		down_write(&block_group->data_rwsem);
1265 		spin_lock(&block_group->lock);
1266 		if (block_group->delalloc_bytes) {
1267 			block_group->disk_cache_state = BTRFS_DC_WRITTEN;
1268 			spin_unlock(&block_group->lock);
1269 			up_write(&block_group->data_rwsem);
1270 			BTRFS_I(inode)->generation = 0;
1271 			ret = 0;
1272 			must_iput = 1;
1273 			goto out;
1274 		}
1275 		spin_unlock(&block_group->lock);
1276 	}
1277 
1278 	/* Lock all pages first so we can lock the extent safely. */
1279 	ret = io_ctl_prepare_pages(io_ctl, inode, 0);
1280 	if (ret)
1281 		goto out_unlock;
1282 
1283 	lock_extent_bits(&BTRFS_I(inode)->io_tree, 0, i_size_read(inode) - 1,
1284 			 &cached_state);
1285 
1286 	io_ctl_set_generation(io_ctl, trans->transid);
1287 
1288 	mutex_lock(&ctl->cache_writeout_mutex);
1289 	/* Write out the extent entries in the free space cache */
1290 	spin_lock(&ctl->tree_lock);
1291 	ret = write_cache_extent_entries(io_ctl, ctl,
1292 					 block_group, &entries, &bitmaps,
1293 					 &bitmap_list);
1294 	if (ret)
1295 		goto out_nospc_locked;
1296 
1297 	/*
1298 	 * Some spaces that are freed in the current transaction are pinned,
1299 	 * they will be added into free space cache after the transaction is
1300 	 * committed, we shouldn't lose them.
1301 	 *
1302 	 * If this changes while we are working we'll get added back to
1303 	 * the dirty list and redo it.  No locking needed
1304 	 */
1305 	ret = write_pinned_extent_entries(block_group, io_ctl, &entries);
1306 	if (ret)
1307 		goto out_nospc_locked;
1308 
1309 	/*
1310 	 * At last, we write out all the bitmaps and keep cache_writeout_mutex
1311 	 * locked while doing it because a concurrent trim can be manipulating
1312 	 * or freeing the bitmap.
1313 	 */
1314 	ret = write_bitmap_entries(io_ctl, &bitmap_list);
1315 	spin_unlock(&ctl->tree_lock);
1316 	mutex_unlock(&ctl->cache_writeout_mutex);
1317 	if (ret)
1318 		goto out_nospc;
1319 
1320 	/* Zero out the rest of the pages just to make sure */
1321 	io_ctl_zero_remaining_pages(io_ctl);
1322 
1323 	/* Everything is written out, now we dirty the pages in the file. */
1324 	ret = btrfs_dirty_pages(inode, io_ctl->pages, io_ctl->num_pages, 0,
1325 				i_size_read(inode), &cached_state);
1326 	if (ret)
1327 		goto out_nospc;
1328 
1329 	if (block_group && (block_group->flags & BTRFS_BLOCK_GROUP_DATA))
1330 		up_write(&block_group->data_rwsem);
1331 	/*
1332 	 * Release the pages and unlock the extent, we will flush
1333 	 * them out later
1334 	 */
1335 	io_ctl_drop_pages(io_ctl);
1336 	io_ctl_free(io_ctl);
1337 
1338 	unlock_extent_cached(&BTRFS_I(inode)->io_tree, 0,
1339 			     i_size_read(inode) - 1, &cached_state);
1340 
1341 	/*
1342 	 * at this point the pages are under IO and we're happy,
1343 	 * The caller is responsible for waiting on them and updating
1344 	 * the cache and the inode
1345 	 */
1346 	io_ctl->entries = entries;
1347 	io_ctl->bitmaps = bitmaps;
1348 
1349 	ret = btrfs_fdatawrite_range(inode, 0, (u64)-1);
1350 	if (ret)
1351 		goto out;
1352 
1353 	return 0;
1354 
1355 out:
1356 	io_ctl->inode = NULL;
1357 	io_ctl_free(io_ctl);
1358 	if (ret) {
1359 		invalidate_inode_pages2(inode->i_mapping);
1360 		BTRFS_I(inode)->generation = 0;
1361 	}
1362 	btrfs_update_inode(trans, root, inode);
1363 	if (must_iput)
1364 		iput(inode);
1365 	return ret;
1366 
1367 out_nospc_locked:
1368 	cleanup_bitmap_list(&bitmap_list);
1369 	spin_unlock(&ctl->tree_lock);
1370 	mutex_unlock(&ctl->cache_writeout_mutex);
1371 
1372 out_nospc:
1373 	cleanup_write_cache_enospc(inode, io_ctl, &cached_state);
1374 
1375 out_unlock:
1376 	if (block_group && (block_group->flags & BTRFS_BLOCK_GROUP_DATA))
1377 		up_write(&block_group->data_rwsem);
1378 
1379 	goto out;
1380 }
1381 
btrfs_write_out_cache(struct btrfs_trans_handle * trans,struct btrfs_block_group_cache * block_group,struct btrfs_path * path)1382 int btrfs_write_out_cache(struct btrfs_trans_handle *trans,
1383 			  struct btrfs_block_group_cache *block_group,
1384 			  struct btrfs_path *path)
1385 {
1386 	struct btrfs_fs_info *fs_info = trans->fs_info;
1387 	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
1388 	struct inode *inode;
1389 	int ret = 0;
1390 
1391 	spin_lock(&block_group->lock);
1392 	if (block_group->disk_cache_state < BTRFS_DC_SETUP) {
1393 		spin_unlock(&block_group->lock);
1394 		return 0;
1395 	}
1396 	spin_unlock(&block_group->lock);
1397 
1398 	inode = lookup_free_space_inode(block_group, path);
1399 	if (IS_ERR(inode))
1400 		return 0;
1401 
1402 	ret = __btrfs_write_out_cache(fs_info->tree_root, inode, ctl,
1403 				block_group, &block_group->io_ctl, trans);
1404 	if (ret) {
1405 #ifdef DEBUG
1406 		btrfs_err(fs_info,
1407 			  "failed to write free space cache for block group %llu",
1408 			  block_group->key.objectid);
1409 #endif
1410 		spin_lock(&block_group->lock);
1411 		block_group->disk_cache_state = BTRFS_DC_ERROR;
1412 		spin_unlock(&block_group->lock);
1413 
1414 		block_group->io_ctl.inode = NULL;
1415 		iput(inode);
1416 	}
1417 
1418 	/*
1419 	 * if ret == 0 the caller is expected to call btrfs_wait_cache_io
1420 	 * to wait for IO and put the inode
1421 	 */
1422 
1423 	return ret;
1424 }
1425 
offset_to_bit(u64 bitmap_start,u32 unit,u64 offset)1426 static inline unsigned long offset_to_bit(u64 bitmap_start, u32 unit,
1427 					  u64 offset)
1428 {
1429 	ASSERT(offset >= bitmap_start);
1430 	offset -= bitmap_start;
1431 	return (unsigned long)(div_u64(offset, unit));
1432 }
1433 
bytes_to_bits(u64 bytes,u32 unit)1434 static inline unsigned long bytes_to_bits(u64 bytes, u32 unit)
1435 {
1436 	return (unsigned long)(div_u64(bytes, unit));
1437 }
1438 
offset_to_bitmap(struct btrfs_free_space_ctl * ctl,u64 offset)1439 static inline u64 offset_to_bitmap(struct btrfs_free_space_ctl *ctl,
1440 				   u64 offset)
1441 {
1442 	u64 bitmap_start;
1443 	u64 bytes_per_bitmap;
1444 
1445 	bytes_per_bitmap = BITS_PER_BITMAP * ctl->unit;
1446 	bitmap_start = offset - ctl->start;
1447 	bitmap_start = div64_u64(bitmap_start, bytes_per_bitmap);
1448 	bitmap_start *= bytes_per_bitmap;
1449 	bitmap_start += ctl->start;
1450 
1451 	return bitmap_start;
1452 }
1453 
tree_insert_offset(struct rb_root * root,u64 offset,struct rb_node * node,int bitmap)1454 static int tree_insert_offset(struct rb_root *root, u64 offset,
1455 			      struct rb_node *node, int bitmap)
1456 {
1457 	struct rb_node **p = &root->rb_node;
1458 	struct rb_node *parent = NULL;
1459 	struct btrfs_free_space *info;
1460 
1461 	while (*p) {
1462 		parent = *p;
1463 		info = rb_entry(parent, struct btrfs_free_space, offset_index);
1464 
1465 		if (offset < info->offset) {
1466 			p = &(*p)->rb_left;
1467 		} else if (offset > info->offset) {
1468 			p = &(*p)->rb_right;
1469 		} else {
1470 			/*
1471 			 * we could have a bitmap entry and an extent entry
1472 			 * share the same offset.  If this is the case, we want
1473 			 * the extent entry to always be found first if we do a
1474 			 * linear search through the tree, since we want to have
1475 			 * the quickest allocation time, and allocating from an
1476 			 * extent is faster than allocating from a bitmap.  So
1477 			 * if we're inserting a bitmap and we find an entry at
1478 			 * this offset, we want to go right, or after this entry
1479 			 * logically.  If we are inserting an extent and we've
1480 			 * found a bitmap, we want to go left, or before
1481 			 * logically.
1482 			 */
1483 			if (bitmap) {
1484 				if (info->bitmap) {
1485 					WARN_ON_ONCE(1);
1486 					return -EEXIST;
1487 				}
1488 				p = &(*p)->rb_right;
1489 			} else {
1490 				if (!info->bitmap) {
1491 					WARN_ON_ONCE(1);
1492 					return -EEXIST;
1493 				}
1494 				p = &(*p)->rb_left;
1495 			}
1496 		}
1497 	}
1498 
1499 	rb_link_node(node, parent, p);
1500 	rb_insert_color(node, root);
1501 
1502 	return 0;
1503 }
1504 
1505 /*
1506  * searches the tree for the given offset.
1507  *
1508  * fuzzy - If this is set, then we are trying to make an allocation, and we just
1509  * want a section that has at least bytes size and comes at or after the given
1510  * offset.
1511  */
1512 static struct btrfs_free_space *
tree_search_offset(struct btrfs_free_space_ctl * ctl,u64 offset,int bitmap_only,int fuzzy)1513 tree_search_offset(struct btrfs_free_space_ctl *ctl,
1514 		   u64 offset, int bitmap_only, int fuzzy)
1515 {
1516 	struct rb_node *n = ctl->free_space_offset.rb_node;
1517 	struct btrfs_free_space *entry, *prev = NULL;
1518 
1519 	/* find entry that is closest to the 'offset' */
1520 	while (1) {
1521 		if (!n) {
1522 			entry = NULL;
1523 			break;
1524 		}
1525 
1526 		entry = rb_entry(n, struct btrfs_free_space, offset_index);
1527 		prev = entry;
1528 
1529 		if (offset < entry->offset)
1530 			n = n->rb_left;
1531 		else if (offset > entry->offset)
1532 			n = n->rb_right;
1533 		else
1534 			break;
1535 	}
1536 
1537 	if (bitmap_only) {
1538 		if (!entry)
1539 			return NULL;
1540 		if (entry->bitmap)
1541 			return entry;
1542 
1543 		/*
1544 		 * bitmap entry and extent entry may share same offset,
1545 		 * in that case, bitmap entry comes after extent entry.
1546 		 */
1547 		n = rb_next(n);
1548 		if (!n)
1549 			return NULL;
1550 		entry = rb_entry(n, struct btrfs_free_space, offset_index);
1551 		if (entry->offset != offset)
1552 			return NULL;
1553 
1554 		WARN_ON(!entry->bitmap);
1555 		return entry;
1556 	} else if (entry) {
1557 		if (entry->bitmap) {
1558 			/*
1559 			 * if previous extent entry covers the offset,
1560 			 * we should return it instead of the bitmap entry
1561 			 */
1562 			n = rb_prev(&entry->offset_index);
1563 			if (n) {
1564 				prev = rb_entry(n, struct btrfs_free_space,
1565 						offset_index);
1566 				if (!prev->bitmap &&
1567 				    prev->offset + prev->bytes > offset)
1568 					entry = prev;
1569 			}
1570 		}
1571 		return entry;
1572 	}
1573 
1574 	if (!prev)
1575 		return NULL;
1576 
1577 	/* find last entry before the 'offset' */
1578 	entry = prev;
1579 	if (entry->offset > offset) {
1580 		n = rb_prev(&entry->offset_index);
1581 		if (n) {
1582 			entry = rb_entry(n, struct btrfs_free_space,
1583 					offset_index);
1584 			ASSERT(entry->offset <= offset);
1585 		} else {
1586 			if (fuzzy)
1587 				return entry;
1588 			else
1589 				return NULL;
1590 		}
1591 	}
1592 
1593 	if (entry->bitmap) {
1594 		n = rb_prev(&entry->offset_index);
1595 		if (n) {
1596 			prev = rb_entry(n, struct btrfs_free_space,
1597 					offset_index);
1598 			if (!prev->bitmap &&
1599 			    prev->offset + prev->bytes > offset)
1600 				return prev;
1601 		}
1602 		if (entry->offset + BITS_PER_BITMAP * ctl->unit > offset)
1603 			return entry;
1604 	} else if (entry->offset + entry->bytes > offset)
1605 		return entry;
1606 
1607 	if (!fuzzy)
1608 		return NULL;
1609 
1610 	while (1) {
1611 		if (entry->bitmap) {
1612 			if (entry->offset + BITS_PER_BITMAP *
1613 			    ctl->unit > offset)
1614 				break;
1615 		} else {
1616 			if (entry->offset + entry->bytes > offset)
1617 				break;
1618 		}
1619 
1620 		n = rb_next(&entry->offset_index);
1621 		if (!n)
1622 			return NULL;
1623 		entry = rb_entry(n, struct btrfs_free_space, offset_index);
1624 	}
1625 	return entry;
1626 }
1627 
1628 static inline void
__unlink_free_space(struct btrfs_free_space_ctl * ctl,struct btrfs_free_space * info)1629 __unlink_free_space(struct btrfs_free_space_ctl *ctl,
1630 		    struct btrfs_free_space *info)
1631 {
1632 	rb_erase(&info->offset_index, &ctl->free_space_offset);
1633 	ctl->free_extents--;
1634 }
1635 
unlink_free_space(struct btrfs_free_space_ctl * ctl,struct btrfs_free_space * info)1636 static void unlink_free_space(struct btrfs_free_space_ctl *ctl,
1637 			      struct btrfs_free_space *info)
1638 {
1639 	__unlink_free_space(ctl, info);
1640 	ctl->free_space -= info->bytes;
1641 }
1642 
link_free_space(struct btrfs_free_space_ctl * ctl,struct btrfs_free_space * info)1643 static int link_free_space(struct btrfs_free_space_ctl *ctl,
1644 			   struct btrfs_free_space *info)
1645 {
1646 	int ret = 0;
1647 
1648 	ASSERT(info->bytes || info->bitmap);
1649 	ret = tree_insert_offset(&ctl->free_space_offset, info->offset,
1650 				 &info->offset_index, (info->bitmap != NULL));
1651 	if (ret)
1652 		return ret;
1653 
1654 	ctl->free_space += info->bytes;
1655 	ctl->free_extents++;
1656 	return ret;
1657 }
1658 
recalculate_thresholds(struct btrfs_free_space_ctl * ctl)1659 static void recalculate_thresholds(struct btrfs_free_space_ctl *ctl)
1660 {
1661 	struct btrfs_block_group_cache *block_group = ctl->private;
1662 	u64 max_bytes;
1663 	u64 bitmap_bytes;
1664 	u64 extent_bytes;
1665 	u64 size = block_group->key.offset;
1666 	u64 bytes_per_bg = BITS_PER_BITMAP * ctl->unit;
1667 	u64 max_bitmaps = div64_u64(size + bytes_per_bg - 1, bytes_per_bg);
1668 
1669 	max_bitmaps = max_t(u64, max_bitmaps, 1);
1670 
1671 	ASSERT(ctl->total_bitmaps <= max_bitmaps);
1672 
1673 	/*
1674 	 * The goal is to keep the total amount of memory used per 1gb of space
1675 	 * at or below 32k, so we need to adjust how much memory we allow to be
1676 	 * used by extent based free space tracking
1677 	 */
1678 	if (size < SZ_1G)
1679 		max_bytes = MAX_CACHE_BYTES_PER_GIG;
1680 	else
1681 		max_bytes = MAX_CACHE_BYTES_PER_GIG * div_u64(size, SZ_1G);
1682 
1683 	/*
1684 	 * we want to account for 1 more bitmap than what we have so we can make
1685 	 * sure we don't go over our overall goal of MAX_CACHE_BYTES_PER_GIG as
1686 	 * we add more bitmaps.
1687 	 */
1688 	bitmap_bytes = (ctl->total_bitmaps + 1) * ctl->unit;
1689 
1690 	if (bitmap_bytes >= max_bytes) {
1691 		ctl->extents_thresh = 0;
1692 		return;
1693 	}
1694 
1695 	/*
1696 	 * we want the extent entry threshold to always be at most 1/2 the max
1697 	 * bytes we can have, or whatever is less than that.
1698 	 */
1699 	extent_bytes = max_bytes - bitmap_bytes;
1700 	extent_bytes = min_t(u64, extent_bytes, max_bytes >> 1);
1701 
1702 	ctl->extents_thresh =
1703 		div_u64(extent_bytes, sizeof(struct btrfs_free_space));
1704 }
1705 
__bitmap_clear_bits(struct btrfs_free_space_ctl * ctl,struct btrfs_free_space * info,u64 offset,u64 bytes)1706 static inline void __bitmap_clear_bits(struct btrfs_free_space_ctl *ctl,
1707 				       struct btrfs_free_space *info,
1708 				       u64 offset, u64 bytes)
1709 {
1710 	unsigned long start, count;
1711 
1712 	start = offset_to_bit(info->offset, ctl->unit, offset);
1713 	count = bytes_to_bits(bytes, ctl->unit);
1714 	ASSERT(start + count <= BITS_PER_BITMAP);
1715 
1716 	bitmap_clear(info->bitmap, start, count);
1717 
1718 	info->bytes -= bytes;
1719 	if (info->max_extent_size > ctl->unit)
1720 		info->max_extent_size = 0;
1721 }
1722 
bitmap_clear_bits(struct btrfs_free_space_ctl * ctl,struct btrfs_free_space * info,u64 offset,u64 bytes)1723 static void bitmap_clear_bits(struct btrfs_free_space_ctl *ctl,
1724 			      struct btrfs_free_space *info, u64 offset,
1725 			      u64 bytes)
1726 {
1727 	__bitmap_clear_bits(ctl, info, offset, bytes);
1728 	ctl->free_space -= bytes;
1729 }
1730 
bitmap_set_bits(struct btrfs_free_space_ctl * ctl,struct btrfs_free_space * info,u64 offset,u64 bytes)1731 static void bitmap_set_bits(struct btrfs_free_space_ctl *ctl,
1732 			    struct btrfs_free_space *info, u64 offset,
1733 			    u64 bytes)
1734 {
1735 	unsigned long start, count;
1736 
1737 	start = offset_to_bit(info->offset, ctl->unit, offset);
1738 	count = bytes_to_bits(bytes, ctl->unit);
1739 	ASSERT(start + count <= BITS_PER_BITMAP);
1740 
1741 	bitmap_set(info->bitmap, start, count);
1742 
1743 	info->bytes += bytes;
1744 	ctl->free_space += bytes;
1745 }
1746 
1747 /*
1748  * If we can not find suitable extent, we will use bytes to record
1749  * the size of the max extent.
1750  */
search_bitmap(struct btrfs_free_space_ctl * ctl,struct btrfs_free_space * bitmap_info,u64 * offset,u64 * bytes,bool for_alloc)1751 static int search_bitmap(struct btrfs_free_space_ctl *ctl,
1752 			 struct btrfs_free_space *bitmap_info, u64 *offset,
1753 			 u64 *bytes, bool for_alloc)
1754 {
1755 	unsigned long found_bits = 0;
1756 	unsigned long max_bits = 0;
1757 	unsigned long bits, i;
1758 	unsigned long next_zero;
1759 	unsigned long extent_bits;
1760 
1761 	/*
1762 	 * Skip searching the bitmap if we don't have a contiguous section that
1763 	 * is large enough for this allocation.
1764 	 */
1765 	if (for_alloc &&
1766 	    bitmap_info->max_extent_size &&
1767 	    bitmap_info->max_extent_size < *bytes) {
1768 		*bytes = bitmap_info->max_extent_size;
1769 		return -1;
1770 	}
1771 
1772 	i = offset_to_bit(bitmap_info->offset, ctl->unit,
1773 			  max_t(u64, *offset, bitmap_info->offset));
1774 	bits = bytes_to_bits(*bytes, ctl->unit);
1775 
1776 	for_each_set_bit_from(i, bitmap_info->bitmap, BITS_PER_BITMAP) {
1777 		if (for_alloc && bits == 1) {
1778 			found_bits = 1;
1779 			break;
1780 		}
1781 		next_zero = find_next_zero_bit(bitmap_info->bitmap,
1782 					       BITS_PER_BITMAP, i);
1783 		extent_bits = next_zero - i;
1784 		if (extent_bits >= bits) {
1785 			found_bits = extent_bits;
1786 			break;
1787 		} else if (extent_bits > max_bits) {
1788 			max_bits = extent_bits;
1789 		}
1790 		i = next_zero;
1791 	}
1792 
1793 	if (found_bits) {
1794 		*offset = (u64)(i * ctl->unit) + bitmap_info->offset;
1795 		*bytes = (u64)(found_bits) * ctl->unit;
1796 		return 0;
1797 	}
1798 
1799 	*bytes = (u64)(max_bits) * ctl->unit;
1800 	bitmap_info->max_extent_size = *bytes;
1801 	return -1;
1802 }
1803 
get_max_extent_size(struct btrfs_free_space * entry)1804 static inline u64 get_max_extent_size(struct btrfs_free_space *entry)
1805 {
1806 	if (entry->bitmap)
1807 		return entry->max_extent_size;
1808 	return entry->bytes;
1809 }
1810 
1811 /* Cache the size of the max extent in bytes */
1812 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)1813 find_free_space(struct btrfs_free_space_ctl *ctl, u64 *offset, u64 *bytes,
1814 		unsigned long align, u64 *max_extent_size)
1815 {
1816 	struct btrfs_free_space *entry;
1817 	struct rb_node *node;
1818 	u64 tmp;
1819 	u64 align_off;
1820 	int ret;
1821 
1822 	if (!ctl->free_space_offset.rb_node)
1823 		goto out;
1824 
1825 	entry = tree_search_offset(ctl, offset_to_bitmap(ctl, *offset), 0, 1);
1826 	if (!entry)
1827 		goto out;
1828 
1829 	for (node = &entry->offset_index; node; node = rb_next(node)) {
1830 		entry = rb_entry(node, struct btrfs_free_space, offset_index);
1831 		if (entry->bytes < *bytes) {
1832 			*max_extent_size = max(get_max_extent_size(entry),
1833 					       *max_extent_size);
1834 			continue;
1835 		}
1836 
1837 		/* make sure the space returned is big enough
1838 		 * to match our requested alignment
1839 		 */
1840 		if (*bytes >= align) {
1841 			tmp = entry->offset - ctl->start + align - 1;
1842 			tmp = div64_u64(tmp, align);
1843 			tmp = tmp * align + ctl->start;
1844 			align_off = tmp - entry->offset;
1845 		} else {
1846 			align_off = 0;
1847 			tmp = entry->offset;
1848 		}
1849 
1850 		if (entry->bytes < *bytes + align_off) {
1851 			*max_extent_size = max(get_max_extent_size(entry),
1852 					       *max_extent_size);
1853 			continue;
1854 		}
1855 
1856 		if (entry->bitmap) {
1857 			u64 size = *bytes;
1858 
1859 			ret = search_bitmap(ctl, entry, &tmp, &size, true);
1860 			if (!ret) {
1861 				*offset = tmp;
1862 				*bytes = size;
1863 				return entry;
1864 			} else {
1865 				*max_extent_size =
1866 					max(get_max_extent_size(entry),
1867 					    *max_extent_size);
1868 			}
1869 			continue;
1870 		}
1871 
1872 		*offset = tmp;
1873 		*bytes = entry->bytes - align_off;
1874 		return entry;
1875 	}
1876 out:
1877 	return NULL;
1878 }
1879 
add_new_bitmap(struct btrfs_free_space_ctl * ctl,struct btrfs_free_space * info,u64 offset)1880 static void add_new_bitmap(struct btrfs_free_space_ctl *ctl,
1881 			   struct btrfs_free_space *info, u64 offset)
1882 {
1883 	info->offset = offset_to_bitmap(ctl, offset);
1884 	info->bytes = 0;
1885 	INIT_LIST_HEAD(&info->list);
1886 	link_free_space(ctl, info);
1887 	ctl->total_bitmaps++;
1888 
1889 	ctl->op->recalc_thresholds(ctl);
1890 }
1891 
free_bitmap(struct btrfs_free_space_ctl * ctl,struct btrfs_free_space * bitmap_info)1892 static void free_bitmap(struct btrfs_free_space_ctl *ctl,
1893 			struct btrfs_free_space *bitmap_info)
1894 {
1895 	unlink_free_space(ctl, bitmap_info);
1896 	kmem_cache_free(btrfs_free_space_bitmap_cachep, bitmap_info->bitmap);
1897 	kmem_cache_free(btrfs_free_space_cachep, bitmap_info);
1898 	ctl->total_bitmaps--;
1899 	ctl->op->recalc_thresholds(ctl);
1900 }
1901 
remove_from_bitmap(struct btrfs_free_space_ctl * ctl,struct btrfs_free_space * bitmap_info,u64 * offset,u64 * bytes)1902 static noinline int remove_from_bitmap(struct btrfs_free_space_ctl *ctl,
1903 			      struct btrfs_free_space *bitmap_info,
1904 			      u64 *offset, u64 *bytes)
1905 {
1906 	u64 end;
1907 	u64 search_start, search_bytes;
1908 	int ret;
1909 
1910 again:
1911 	end = bitmap_info->offset + (u64)(BITS_PER_BITMAP * ctl->unit) - 1;
1912 
1913 	/*
1914 	 * We need to search for bits in this bitmap.  We could only cover some
1915 	 * of the extent in this bitmap thanks to how we add space, so we need
1916 	 * to search for as much as it as we can and clear that amount, and then
1917 	 * go searching for the next bit.
1918 	 */
1919 	search_start = *offset;
1920 	search_bytes = ctl->unit;
1921 	search_bytes = min(search_bytes, end - search_start + 1);
1922 	ret = search_bitmap(ctl, bitmap_info, &search_start, &search_bytes,
1923 			    false);
1924 	if (ret < 0 || search_start != *offset)
1925 		return -EINVAL;
1926 
1927 	/* We may have found more bits than what we need */
1928 	search_bytes = min(search_bytes, *bytes);
1929 
1930 	/* Cannot clear past the end of the bitmap */
1931 	search_bytes = min(search_bytes, end - search_start + 1);
1932 
1933 	bitmap_clear_bits(ctl, bitmap_info, search_start, search_bytes);
1934 	*offset += search_bytes;
1935 	*bytes -= search_bytes;
1936 
1937 	if (*bytes) {
1938 		struct rb_node *next = rb_next(&bitmap_info->offset_index);
1939 		if (!bitmap_info->bytes)
1940 			free_bitmap(ctl, bitmap_info);
1941 
1942 		/*
1943 		 * no entry after this bitmap, but we still have bytes to
1944 		 * remove, so something has gone wrong.
1945 		 */
1946 		if (!next)
1947 			return -EINVAL;
1948 
1949 		bitmap_info = rb_entry(next, struct btrfs_free_space,
1950 				       offset_index);
1951 
1952 		/*
1953 		 * if the next entry isn't a bitmap we need to return to let the
1954 		 * extent stuff do its work.
1955 		 */
1956 		if (!bitmap_info->bitmap)
1957 			return -EAGAIN;
1958 
1959 		/*
1960 		 * Ok the next item is a bitmap, but it may not actually hold
1961 		 * the information for the rest of this free space stuff, so
1962 		 * look for it, and if we don't find it return so we can try
1963 		 * everything over again.
1964 		 */
1965 		search_start = *offset;
1966 		search_bytes = ctl->unit;
1967 		ret = search_bitmap(ctl, bitmap_info, &search_start,
1968 				    &search_bytes, false);
1969 		if (ret < 0 || search_start != *offset)
1970 			return -EAGAIN;
1971 
1972 		goto again;
1973 	} else if (!bitmap_info->bytes)
1974 		free_bitmap(ctl, bitmap_info);
1975 
1976 	return 0;
1977 }
1978 
add_bytes_to_bitmap(struct btrfs_free_space_ctl * ctl,struct btrfs_free_space * info,u64 offset,u64 bytes)1979 static u64 add_bytes_to_bitmap(struct btrfs_free_space_ctl *ctl,
1980 			       struct btrfs_free_space *info, u64 offset,
1981 			       u64 bytes)
1982 {
1983 	u64 bytes_to_set = 0;
1984 	u64 end;
1985 
1986 	end = info->offset + (u64)(BITS_PER_BITMAP * ctl->unit);
1987 
1988 	bytes_to_set = min(end - offset, bytes);
1989 
1990 	bitmap_set_bits(ctl, info, offset, bytes_to_set);
1991 
1992 	/*
1993 	 * We set some bytes, we have no idea what the max extent size is
1994 	 * anymore.
1995 	 */
1996 	info->max_extent_size = 0;
1997 
1998 	return bytes_to_set;
1999 
2000 }
2001 
use_bitmap(struct btrfs_free_space_ctl * ctl,struct btrfs_free_space * info)2002 static bool use_bitmap(struct btrfs_free_space_ctl *ctl,
2003 		      struct btrfs_free_space *info)
2004 {
2005 	struct btrfs_block_group_cache *block_group = ctl->private;
2006 	struct btrfs_fs_info *fs_info = block_group->fs_info;
2007 	bool forced = false;
2008 
2009 #ifdef CONFIG_BTRFS_DEBUG
2010 	if (btrfs_should_fragment_free_space(block_group))
2011 		forced = true;
2012 #endif
2013 
2014 	/*
2015 	 * If we are below the extents threshold then we can add this as an
2016 	 * extent, and don't have to deal with the bitmap
2017 	 */
2018 	if (!forced && ctl->free_extents < ctl->extents_thresh) {
2019 		/*
2020 		 * If this block group has some small extents we don't want to
2021 		 * use up all of our free slots in the cache with them, we want
2022 		 * to reserve them to larger extents, however if we have plenty
2023 		 * of cache left then go ahead an dadd them, no sense in adding
2024 		 * the overhead of a bitmap if we don't have to.
2025 		 */
2026 		if (info->bytes <= fs_info->sectorsize * 4) {
2027 			if (ctl->free_extents * 2 <= ctl->extents_thresh)
2028 				return false;
2029 		} else {
2030 			return false;
2031 		}
2032 	}
2033 
2034 	/*
2035 	 * The original block groups from mkfs can be really small, like 8
2036 	 * megabytes, so don't bother with a bitmap for those entries.  However
2037 	 * some block groups can be smaller than what a bitmap would cover but
2038 	 * are still large enough that they could overflow the 32k memory limit,
2039 	 * so allow those block groups to still be allowed to have a bitmap
2040 	 * entry.
2041 	 */
2042 	if (((BITS_PER_BITMAP * ctl->unit) >> 1) > block_group->key.offset)
2043 		return false;
2044 
2045 	return true;
2046 }
2047 
2048 static const struct btrfs_free_space_op free_space_op = {
2049 	.recalc_thresholds	= recalculate_thresholds,
2050 	.use_bitmap		= use_bitmap,
2051 };
2052 
insert_into_bitmap(struct btrfs_free_space_ctl * ctl,struct btrfs_free_space * info)2053 static int insert_into_bitmap(struct btrfs_free_space_ctl *ctl,
2054 			      struct btrfs_free_space *info)
2055 {
2056 	struct btrfs_free_space *bitmap_info;
2057 	struct btrfs_block_group_cache *block_group = NULL;
2058 	int added = 0;
2059 	u64 bytes, offset, bytes_added;
2060 	int ret;
2061 
2062 	bytes = info->bytes;
2063 	offset = info->offset;
2064 
2065 	if (!ctl->op->use_bitmap(ctl, info))
2066 		return 0;
2067 
2068 	if (ctl->op == &free_space_op)
2069 		block_group = ctl->private;
2070 again:
2071 	/*
2072 	 * Since we link bitmaps right into the cluster we need to see if we
2073 	 * have a cluster here, and if so and it has our bitmap we need to add
2074 	 * the free space to that bitmap.
2075 	 */
2076 	if (block_group && !list_empty(&block_group->cluster_list)) {
2077 		struct btrfs_free_cluster *cluster;
2078 		struct rb_node *node;
2079 		struct btrfs_free_space *entry;
2080 
2081 		cluster = list_entry(block_group->cluster_list.next,
2082 				     struct btrfs_free_cluster,
2083 				     block_group_list);
2084 		spin_lock(&cluster->lock);
2085 		node = rb_first(&cluster->root);
2086 		if (!node) {
2087 			spin_unlock(&cluster->lock);
2088 			goto no_cluster_bitmap;
2089 		}
2090 
2091 		entry = rb_entry(node, struct btrfs_free_space, offset_index);
2092 		if (!entry->bitmap) {
2093 			spin_unlock(&cluster->lock);
2094 			goto no_cluster_bitmap;
2095 		}
2096 
2097 		if (entry->offset == offset_to_bitmap(ctl, offset)) {
2098 			bytes_added = add_bytes_to_bitmap(ctl, entry,
2099 							  offset, bytes);
2100 			bytes -= bytes_added;
2101 			offset += bytes_added;
2102 		}
2103 		spin_unlock(&cluster->lock);
2104 		if (!bytes) {
2105 			ret = 1;
2106 			goto out;
2107 		}
2108 	}
2109 
2110 no_cluster_bitmap:
2111 	bitmap_info = tree_search_offset(ctl, offset_to_bitmap(ctl, offset),
2112 					 1, 0);
2113 	if (!bitmap_info) {
2114 		ASSERT(added == 0);
2115 		goto new_bitmap;
2116 	}
2117 
2118 	bytes_added = add_bytes_to_bitmap(ctl, bitmap_info, offset, bytes);
2119 	bytes -= bytes_added;
2120 	offset += bytes_added;
2121 	added = 0;
2122 
2123 	if (!bytes) {
2124 		ret = 1;
2125 		goto out;
2126 	} else
2127 		goto again;
2128 
2129 new_bitmap:
2130 	if (info && info->bitmap) {
2131 		add_new_bitmap(ctl, info, offset);
2132 		added = 1;
2133 		info = NULL;
2134 		goto again;
2135 	} else {
2136 		spin_unlock(&ctl->tree_lock);
2137 
2138 		/* no pre-allocated info, allocate a new one */
2139 		if (!info) {
2140 			info = kmem_cache_zalloc(btrfs_free_space_cachep,
2141 						 GFP_NOFS);
2142 			if (!info) {
2143 				spin_lock(&ctl->tree_lock);
2144 				ret = -ENOMEM;
2145 				goto out;
2146 			}
2147 		}
2148 
2149 		/* allocate the bitmap */
2150 		info->bitmap = kmem_cache_zalloc(btrfs_free_space_bitmap_cachep,
2151 						 GFP_NOFS);
2152 		spin_lock(&ctl->tree_lock);
2153 		if (!info->bitmap) {
2154 			ret = -ENOMEM;
2155 			goto out;
2156 		}
2157 		goto again;
2158 	}
2159 
2160 out:
2161 	if (info) {
2162 		if (info->bitmap)
2163 			kmem_cache_free(btrfs_free_space_bitmap_cachep,
2164 					info->bitmap);
2165 		kmem_cache_free(btrfs_free_space_cachep, info);
2166 	}
2167 
2168 	return ret;
2169 }
2170 
try_merge_free_space(struct btrfs_free_space_ctl * ctl,struct btrfs_free_space * info,bool update_stat)2171 static bool try_merge_free_space(struct btrfs_free_space_ctl *ctl,
2172 			  struct btrfs_free_space *info, bool update_stat)
2173 {
2174 	struct btrfs_free_space *left_info = NULL;
2175 	struct btrfs_free_space *right_info;
2176 	bool merged = false;
2177 	u64 offset = info->offset;
2178 	u64 bytes = info->bytes;
2179 
2180 	/*
2181 	 * first we want to see if there is free space adjacent to the range we
2182 	 * are adding, if there is remove that struct and add a new one to
2183 	 * cover the entire range
2184 	 */
2185 	right_info = tree_search_offset(ctl, offset + bytes, 0, 0);
2186 	if (right_info && rb_prev(&right_info->offset_index))
2187 		left_info = rb_entry(rb_prev(&right_info->offset_index),
2188 				     struct btrfs_free_space, offset_index);
2189 	else if (!right_info)
2190 		left_info = tree_search_offset(ctl, offset - 1, 0, 0);
2191 
2192 	if (right_info && !right_info->bitmap) {
2193 		if (update_stat)
2194 			unlink_free_space(ctl, right_info);
2195 		else
2196 			__unlink_free_space(ctl, right_info);
2197 		info->bytes += right_info->bytes;
2198 		kmem_cache_free(btrfs_free_space_cachep, right_info);
2199 		merged = true;
2200 	}
2201 
2202 	if (left_info && !left_info->bitmap &&
2203 	    left_info->offset + left_info->bytes == offset) {
2204 		if (update_stat)
2205 			unlink_free_space(ctl, left_info);
2206 		else
2207 			__unlink_free_space(ctl, left_info);
2208 		info->offset = left_info->offset;
2209 		info->bytes += left_info->bytes;
2210 		kmem_cache_free(btrfs_free_space_cachep, left_info);
2211 		merged = true;
2212 	}
2213 
2214 	return merged;
2215 }
2216 
steal_from_bitmap_to_end(struct btrfs_free_space_ctl * ctl,struct btrfs_free_space * info,bool update_stat)2217 static bool steal_from_bitmap_to_end(struct btrfs_free_space_ctl *ctl,
2218 				     struct btrfs_free_space *info,
2219 				     bool update_stat)
2220 {
2221 	struct btrfs_free_space *bitmap;
2222 	unsigned long i;
2223 	unsigned long j;
2224 	const u64 end = info->offset + info->bytes;
2225 	const u64 bitmap_offset = offset_to_bitmap(ctl, end);
2226 	u64 bytes;
2227 
2228 	bitmap = tree_search_offset(ctl, bitmap_offset, 1, 0);
2229 	if (!bitmap)
2230 		return false;
2231 
2232 	i = offset_to_bit(bitmap->offset, ctl->unit, end);
2233 	j = find_next_zero_bit(bitmap->bitmap, BITS_PER_BITMAP, i);
2234 	if (j == i)
2235 		return false;
2236 	bytes = (j - i) * ctl->unit;
2237 	info->bytes += bytes;
2238 
2239 	if (update_stat)
2240 		bitmap_clear_bits(ctl, bitmap, end, bytes);
2241 	else
2242 		__bitmap_clear_bits(ctl, bitmap, end, bytes);
2243 
2244 	if (!bitmap->bytes)
2245 		free_bitmap(ctl, bitmap);
2246 
2247 	return true;
2248 }
2249 
steal_from_bitmap_to_front(struct btrfs_free_space_ctl * ctl,struct btrfs_free_space * info,bool update_stat)2250 static bool steal_from_bitmap_to_front(struct btrfs_free_space_ctl *ctl,
2251 				       struct btrfs_free_space *info,
2252 				       bool update_stat)
2253 {
2254 	struct btrfs_free_space *bitmap;
2255 	u64 bitmap_offset;
2256 	unsigned long i;
2257 	unsigned long j;
2258 	unsigned long prev_j;
2259 	u64 bytes;
2260 
2261 	bitmap_offset = offset_to_bitmap(ctl, info->offset);
2262 	/* If we're on a boundary, try the previous logical bitmap. */
2263 	if (bitmap_offset == info->offset) {
2264 		if (info->offset == 0)
2265 			return false;
2266 		bitmap_offset = offset_to_bitmap(ctl, info->offset - 1);
2267 	}
2268 
2269 	bitmap = tree_search_offset(ctl, bitmap_offset, 1, 0);
2270 	if (!bitmap)
2271 		return false;
2272 
2273 	i = offset_to_bit(bitmap->offset, ctl->unit, info->offset) - 1;
2274 	j = 0;
2275 	prev_j = (unsigned long)-1;
2276 	for_each_clear_bit_from(j, bitmap->bitmap, BITS_PER_BITMAP) {
2277 		if (j > i)
2278 			break;
2279 		prev_j = j;
2280 	}
2281 	if (prev_j == i)
2282 		return false;
2283 
2284 	if (prev_j == (unsigned long)-1)
2285 		bytes = (i + 1) * ctl->unit;
2286 	else
2287 		bytes = (i - prev_j) * ctl->unit;
2288 
2289 	info->offset -= bytes;
2290 	info->bytes += bytes;
2291 
2292 	if (update_stat)
2293 		bitmap_clear_bits(ctl, bitmap, info->offset, bytes);
2294 	else
2295 		__bitmap_clear_bits(ctl, bitmap, info->offset, bytes);
2296 
2297 	if (!bitmap->bytes)
2298 		free_bitmap(ctl, bitmap);
2299 
2300 	return true;
2301 }
2302 
2303 /*
2304  * We prefer always to allocate from extent entries, both for clustered and
2305  * non-clustered allocation requests. So when attempting to add a new extent
2306  * entry, try to see if there's adjacent free space in bitmap entries, and if
2307  * there is, migrate that space from the bitmaps to the extent.
2308  * Like this we get better chances of satisfying space allocation requests
2309  * because we attempt to satisfy them based on a single cache entry, and never
2310  * on 2 or more entries - even if the entries represent a contiguous free space
2311  * region (e.g. 1 extent entry + 1 bitmap entry starting where the extent entry
2312  * ends).
2313  */
steal_from_bitmap(struct btrfs_free_space_ctl * ctl,struct btrfs_free_space * info,bool update_stat)2314 static void steal_from_bitmap(struct btrfs_free_space_ctl *ctl,
2315 			      struct btrfs_free_space *info,
2316 			      bool update_stat)
2317 {
2318 	/*
2319 	 * Only work with disconnected entries, as we can change their offset,
2320 	 * and must be extent entries.
2321 	 */
2322 	ASSERT(!info->bitmap);
2323 	ASSERT(RB_EMPTY_NODE(&info->offset_index));
2324 
2325 	if (ctl->total_bitmaps > 0) {
2326 		bool stole_end;
2327 		bool stole_front = false;
2328 
2329 		stole_end = steal_from_bitmap_to_end(ctl, info, update_stat);
2330 		if (ctl->total_bitmaps > 0)
2331 			stole_front = steal_from_bitmap_to_front(ctl, info,
2332 								 update_stat);
2333 
2334 		if (stole_end || stole_front)
2335 			try_merge_free_space(ctl, info, update_stat);
2336 	}
2337 }
2338 
__btrfs_add_free_space(struct btrfs_fs_info * fs_info,struct btrfs_free_space_ctl * ctl,u64 offset,u64 bytes)2339 int __btrfs_add_free_space(struct btrfs_fs_info *fs_info,
2340 			   struct btrfs_free_space_ctl *ctl,
2341 			   u64 offset, u64 bytes)
2342 {
2343 	struct btrfs_free_space *info;
2344 	int ret = 0;
2345 
2346 	info = kmem_cache_zalloc(btrfs_free_space_cachep, GFP_NOFS);
2347 	if (!info)
2348 		return -ENOMEM;
2349 
2350 	info->offset = offset;
2351 	info->bytes = bytes;
2352 	RB_CLEAR_NODE(&info->offset_index);
2353 
2354 	spin_lock(&ctl->tree_lock);
2355 
2356 	if (try_merge_free_space(ctl, info, true))
2357 		goto link;
2358 
2359 	/*
2360 	 * There was no extent directly to the left or right of this new
2361 	 * extent then we know we're going to have to allocate a new extent, so
2362 	 * before we do that see if we need to drop this into a bitmap
2363 	 */
2364 	ret = insert_into_bitmap(ctl, info);
2365 	if (ret < 0) {
2366 		goto out;
2367 	} else if (ret) {
2368 		ret = 0;
2369 		goto out;
2370 	}
2371 link:
2372 	/*
2373 	 * Only steal free space from adjacent bitmaps if we're sure we're not
2374 	 * going to add the new free space to existing bitmap entries - because
2375 	 * that would mean unnecessary work that would be reverted. Therefore
2376 	 * attempt to steal space from bitmaps if we're adding an extent entry.
2377 	 */
2378 	steal_from_bitmap(ctl, info, true);
2379 
2380 	ret = link_free_space(ctl, info);
2381 	if (ret)
2382 		kmem_cache_free(btrfs_free_space_cachep, info);
2383 out:
2384 	spin_unlock(&ctl->tree_lock);
2385 
2386 	if (ret) {
2387 		btrfs_crit(fs_info, "unable to add free space :%d", ret);
2388 		ASSERT(ret != -EEXIST);
2389 	}
2390 
2391 	return ret;
2392 }
2393 
btrfs_add_free_space(struct btrfs_block_group_cache * block_group,u64 bytenr,u64 size)2394 int btrfs_add_free_space(struct btrfs_block_group_cache *block_group,
2395 			 u64 bytenr, u64 size)
2396 {
2397 	return __btrfs_add_free_space(block_group->fs_info,
2398 				      block_group->free_space_ctl,
2399 				      bytenr, size);
2400 }
2401 
btrfs_remove_free_space(struct btrfs_block_group_cache * block_group,u64 offset,u64 bytes)2402 int btrfs_remove_free_space(struct btrfs_block_group_cache *block_group,
2403 			    u64 offset, u64 bytes)
2404 {
2405 	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2406 	struct btrfs_free_space *info;
2407 	int ret;
2408 	bool re_search = false;
2409 
2410 	spin_lock(&ctl->tree_lock);
2411 
2412 again:
2413 	ret = 0;
2414 	if (!bytes)
2415 		goto out_lock;
2416 
2417 	info = tree_search_offset(ctl, offset, 0, 0);
2418 	if (!info) {
2419 		/*
2420 		 * oops didn't find an extent that matched the space we wanted
2421 		 * to remove, look for a bitmap instead
2422 		 */
2423 		info = tree_search_offset(ctl, offset_to_bitmap(ctl, offset),
2424 					  1, 0);
2425 		if (!info) {
2426 			/*
2427 			 * If we found a partial bit of our free space in a
2428 			 * bitmap but then couldn't find the other part this may
2429 			 * be a problem, so WARN about it.
2430 			 */
2431 			WARN_ON(re_search);
2432 			goto out_lock;
2433 		}
2434 	}
2435 
2436 	re_search = false;
2437 	if (!info->bitmap) {
2438 		unlink_free_space(ctl, info);
2439 		if (offset == info->offset) {
2440 			u64 to_free = min(bytes, info->bytes);
2441 
2442 			info->bytes -= to_free;
2443 			info->offset += to_free;
2444 			if (info->bytes) {
2445 				ret = link_free_space(ctl, info);
2446 				WARN_ON(ret);
2447 			} else {
2448 				kmem_cache_free(btrfs_free_space_cachep, info);
2449 			}
2450 
2451 			offset += to_free;
2452 			bytes -= to_free;
2453 			goto again;
2454 		} else {
2455 			u64 old_end = info->bytes + info->offset;
2456 
2457 			info->bytes = offset - info->offset;
2458 			ret = link_free_space(ctl, info);
2459 			WARN_ON(ret);
2460 			if (ret)
2461 				goto out_lock;
2462 
2463 			/* Not enough bytes in this entry to satisfy us */
2464 			if (old_end < offset + bytes) {
2465 				bytes -= old_end - offset;
2466 				offset = old_end;
2467 				goto again;
2468 			} else if (old_end == offset + bytes) {
2469 				/* all done */
2470 				goto out_lock;
2471 			}
2472 			spin_unlock(&ctl->tree_lock);
2473 
2474 			ret = btrfs_add_free_space(block_group, offset + bytes,
2475 						   old_end - (offset + bytes));
2476 			WARN_ON(ret);
2477 			goto out;
2478 		}
2479 	}
2480 
2481 	ret = remove_from_bitmap(ctl, info, &offset, &bytes);
2482 	if (ret == -EAGAIN) {
2483 		re_search = true;
2484 		goto again;
2485 	}
2486 out_lock:
2487 	spin_unlock(&ctl->tree_lock);
2488 out:
2489 	return ret;
2490 }
2491 
btrfs_dump_free_space(struct btrfs_block_group_cache * block_group,u64 bytes)2492 void btrfs_dump_free_space(struct btrfs_block_group_cache *block_group,
2493 			   u64 bytes)
2494 {
2495 	struct btrfs_fs_info *fs_info = block_group->fs_info;
2496 	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2497 	struct btrfs_free_space *info;
2498 	struct rb_node *n;
2499 	int count = 0;
2500 
2501 	spin_lock(&ctl->tree_lock);
2502 	for (n = rb_first(&ctl->free_space_offset); n; n = rb_next(n)) {
2503 		info = rb_entry(n, struct btrfs_free_space, offset_index);
2504 		if (info->bytes >= bytes && !block_group->ro)
2505 			count++;
2506 		btrfs_crit(fs_info, "entry offset %llu, bytes %llu, bitmap %s",
2507 			   info->offset, info->bytes,
2508 		       (info->bitmap) ? "yes" : "no");
2509 	}
2510 	spin_unlock(&ctl->tree_lock);
2511 	btrfs_info(fs_info, "block group has cluster?: %s",
2512 	       list_empty(&block_group->cluster_list) ? "no" : "yes");
2513 	btrfs_info(fs_info,
2514 		   "%d blocks of free space at or bigger than bytes is", count);
2515 }
2516 
btrfs_init_free_space_ctl(struct btrfs_block_group_cache * block_group)2517 void btrfs_init_free_space_ctl(struct btrfs_block_group_cache *block_group)
2518 {
2519 	struct btrfs_fs_info *fs_info = block_group->fs_info;
2520 	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2521 
2522 	spin_lock_init(&ctl->tree_lock);
2523 	ctl->unit = fs_info->sectorsize;
2524 	ctl->start = block_group->key.objectid;
2525 	ctl->private = block_group;
2526 	ctl->op = &free_space_op;
2527 	INIT_LIST_HEAD(&ctl->trimming_ranges);
2528 	mutex_init(&ctl->cache_writeout_mutex);
2529 
2530 	/*
2531 	 * we only want to have 32k of ram per block group for keeping
2532 	 * track of free space, and if we pass 1/2 of that we want to
2533 	 * start converting things over to using bitmaps
2534 	 */
2535 	ctl->extents_thresh = (SZ_32K / 2) / sizeof(struct btrfs_free_space);
2536 }
2537 
2538 /*
2539  * for a given cluster, put all of its extents back into the free
2540  * space cache.  If the block group passed doesn't match the block group
2541  * pointed to by the cluster, someone else raced in and freed the
2542  * cluster already.  In that case, we just return without changing anything
2543  */
2544 static int
__btrfs_return_cluster_to_free_space(struct btrfs_block_group_cache * block_group,struct btrfs_free_cluster * cluster)2545 __btrfs_return_cluster_to_free_space(
2546 			     struct btrfs_block_group_cache *block_group,
2547 			     struct btrfs_free_cluster *cluster)
2548 {
2549 	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2550 	struct btrfs_free_space *entry;
2551 	struct rb_node *node;
2552 
2553 	spin_lock(&cluster->lock);
2554 	if (cluster->block_group != block_group)
2555 		goto out;
2556 
2557 	cluster->block_group = NULL;
2558 	cluster->window_start = 0;
2559 	list_del_init(&cluster->block_group_list);
2560 
2561 	node = rb_first(&cluster->root);
2562 	while (node) {
2563 		bool bitmap;
2564 
2565 		entry = rb_entry(node, struct btrfs_free_space, offset_index);
2566 		node = rb_next(&entry->offset_index);
2567 		rb_erase(&entry->offset_index, &cluster->root);
2568 		RB_CLEAR_NODE(&entry->offset_index);
2569 
2570 		bitmap = (entry->bitmap != NULL);
2571 		if (!bitmap) {
2572 			try_merge_free_space(ctl, entry, false);
2573 			steal_from_bitmap(ctl, entry, false);
2574 		}
2575 		tree_insert_offset(&ctl->free_space_offset,
2576 				   entry->offset, &entry->offset_index, bitmap);
2577 	}
2578 	cluster->root = RB_ROOT;
2579 
2580 out:
2581 	spin_unlock(&cluster->lock);
2582 	btrfs_put_block_group(block_group);
2583 	return 0;
2584 }
2585 
__btrfs_remove_free_space_cache_locked(struct btrfs_free_space_ctl * ctl)2586 static void __btrfs_remove_free_space_cache_locked(
2587 				struct btrfs_free_space_ctl *ctl)
2588 {
2589 	struct btrfs_free_space *info;
2590 	struct rb_node *node;
2591 
2592 	while ((node = rb_last(&ctl->free_space_offset)) != NULL) {
2593 		info = rb_entry(node, struct btrfs_free_space, offset_index);
2594 		if (!info->bitmap) {
2595 			unlink_free_space(ctl, info);
2596 			kmem_cache_free(btrfs_free_space_cachep, info);
2597 		} else {
2598 			free_bitmap(ctl, info);
2599 		}
2600 
2601 		cond_resched_lock(&ctl->tree_lock);
2602 	}
2603 }
2604 
__btrfs_remove_free_space_cache(struct btrfs_free_space_ctl * ctl)2605 void __btrfs_remove_free_space_cache(struct btrfs_free_space_ctl *ctl)
2606 {
2607 	spin_lock(&ctl->tree_lock);
2608 	__btrfs_remove_free_space_cache_locked(ctl);
2609 	spin_unlock(&ctl->tree_lock);
2610 }
2611 
btrfs_remove_free_space_cache(struct btrfs_block_group_cache * block_group)2612 void btrfs_remove_free_space_cache(struct btrfs_block_group_cache *block_group)
2613 {
2614 	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2615 	struct btrfs_free_cluster *cluster;
2616 	struct list_head *head;
2617 
2618 	spin_lock(&ctl->tree_lock);
2619 	while ((head = block_group->cluster_list.next) !=
2620 	       &block_group->cluster_list) {
2621 		cluster = list_entry(head, struct btrfs_free_cluster,
2622 				     block_group_list);
2623 
2624 		WARN_ON(cluster->block_group != block_group);
2625 		__btrfs_return_cluster_to_free_space(block_group, cluster);
2626 
2627 		cond_resched_lock(&ctl->tree_lock);
2628 	}
2629 	__btrfs_remove_free_space_cache_locked(ctl);
2630 	spin_unlock(&ctl->tree_lock);
2631 
2632 }
2633 
btrfs_find_space_for_alloc(struct btrfs_block_group_cache * block_group,u64 offset,u64 bytes,u64 empty_size,u64 * max_extent_size)2634 u64 btrfs_find_space_for_alloc(struct btrfs_block_group_cache *block_group,
2635 			       u64 offset, u64 bytes, u64 empty_size,
2636 			       u64 *max_extent_size)
2637 {
2638 	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2639 	struct btrfs_free_space *entry = NULL;
2640 	u64 bytes_search = bytes + empty_size;
2641 	u64 ret = 0;
2642 	u64 align_gap = 0;
2643 	u64 align_gap_len = 0;
2644 
2645 	spin_lock(&ctl->tree_lock);
2646 	entry = find_free_space(ctl, &offset, &bytes_search,
2647 				block_group->full_stripe_len, max_extent_size);
2648 	if (!entry)
2649 		goto out;
2650 
2651 	ret = offset;
2652 	if (entry->bitmap) {
2653 		bitmap_clear_bits(ctl, entry, offset, bytes);
2654 		if (!entry->bytes)
2655 			free_bitmap(ctl, entry);
2656 	} else {
2657 		unlink_free_space(ctl, entry);
2658 		align_gap_len = offset - entry->offset;
2659 		align_gap = entry->offset;
2660 
2661 		entry->offset = offset + bytes;
2662 		WARN_ON(entry->bytes < bytes + align_gap_len);
2663 
2664 		entry->bytes -= bytes + align_gap_len;
2665 		if (!entry->bytes)
2666 			kmem_cache_free(btrfs_free_space_cachep, entry);
2667 		else
2668 			link_free_space(ctl, entry);
2669 	}
2670 out:
2671 	spin_unlock(&ctl->tree_lock);
2672 
2673 	if (align_gap_len)
2674 		__btrfs_add_free_space(block_group->fs_info, ctl,
2675 				       align_gap, align_gap_len);
2676 	return ret;
2677 }
2678 
2679 /*
2680  * given a cluster, put all of its extents back into the free space
2681  * cache.  If a block group is passed, this function will only free
2682  * a cluster that belongs to the passed block group.
2683  *
2684  * Otherwise, it'll get a reference on the block group pointed to by the
2685  * cluster and remove the cluster from it.
2686  */
btrfs_return_cluster_to_free_space(struct btrfs_block_group_cache * block_group,struct btrfs_free_cluster * cluster)2687 int btrfs_return_cluster_to_free_space(
2688 			       struct btrfs_block_group_cache *block_group,
2689 			       struct btrfs_free_cluster *cluster)
2690 {
2691 	struct btrfs_free_space_ctl *ctl;
2692 	int ret;
2693 
2694 	/* first, get a safe pointer to the block group */
2695 	spin_lock(&cluster->lock);
2696 	if (!block_group) {
2697 		block_group = cluster->block_group;
2698 		if (!block_group) {
2699 			spin_unlock(&cluster->lock);
2700 			return 0;
2701 		}
2702 	} else if (cluster->block_group != block_group) {
2703 		/* someone else has already freed it don't redo their work */
2704 		spin_unlock(&cluster->lock);
2705 		return 0;
2706 	}
2707 	atomic_inc(&block_group->count);
2708 	spin_unlock(&cluster->lock);
2709 
2710 	ctl = block_group->free_space_ctl;
2711 
2712 	/* now return any extents the cluster had on it */
2713 	spin_lock(&ctl->tree_lock);
2714 	ret = __btrfs_return_cluster_to_free_space(block_group, cluster);
2715 	spin_unlock(&ctl->tree_lock);
2716 
2717 	/* finally drop our ref */
2718 	btrfs_put_block_group(block_group);
2719 	return ret;
2720 }
2721 
btrfs_alloc_from_bitmap(struct btrfs_block_group_cache * block_group,struct btrfs_free_cluster * cluster,struct btrfs_free_space * entry,u64 bytes,u64 min_start,u64 * max_extent_size)2722 static u64 btrfs_alloc_from_bitmap(struct btrfs_block_group_cache *block_group,
2723 				   struct btrfs_free_cluster *cluster,
2724 				   struct btrfs_free_space *entry,
2725 				   u64 bytes, u64 min_start,
2726 				   u64 *max_extent_size)
2727 {
2728 	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2729 	int err;
2730 	u64 search_start = cluster->window_start;
2731 	u64 search_bytes = bytes;
2732 	u64 ret = 0;
2733 
2734 	search_start = min_start;
2735 	search_bytes = bytes;
2736 
2737 	err = search_bitmap(ctl, entry, &search_start, &search_bytes, true);
2738 	if (err) {
2739 		*max_extent_size = max(get_max_extent_size(entry),
2740 				       *max_extent_size);
2741 		return 0;
2742 	}
2743 
2744 	ret = search_start;
2745 	__bitmap_clear_bits(ctl, entry, ret, bytes);
2746 
2747 	return ret;
2748 }
2749 
2750 /*
2751  * given a cluster, try to allocate 'bytes' from it, returns 0
2752  * if it couldn't find anything suitably large, or a logical disk offset
2753  * if things worked out
2754  */
btrfs_alloc_from_cluster(struct btrfs_block_group_cache * block_group,struct btrfs_free_cluster * cluster,u64 bytes,u64 min_start,u64 * max_extent_size)2755 u64 btrfs_alloc_from_cluster(struct btrfs_block_group_cache *block_group,
2756 			     struct btrfs_free_cluster *cluster, u64 bytes,
2757 			     u64 min_start, u64 *max_extent_size)
2758 {
2759 	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2760 	struct btrfs_free_space *entry = NULL;
2761 	struct rb_node *node;
2762 	u64 ret = 0;
2763 
2764 	spin_lock(&cluster->lock);
2765 	if (bytes > cluster->max_size)
2766 		goto out;
2767 
2768 	if (cluster->block_group != block_group)
2769 		goto out;
2770 
2771 	node = rb_first(&cluster->root);
2772 	if (!node)
2773 		goto out;
2774 
2775 	entry = rb_entry(node, struct btrfs_free_space, offset_index);
2776 	while (1) {
2777 		if (entry->bytes < bytes)
2778 			*max_extent_size = max(get_max_extent_size(entry),
2779 					       *max_extent_size);
2780 
2781 		if (entry->bytes < bytes ||
2782 		    (!entry->bitmap && entry->offset < min_start)) {
2783 			node = rb_next(&entry->offset_index);
2784 			if (!node)
2785 				break;
2786 			entry = rb_entry(node, struct btrfs_free_space,
2787 					 offset_index);
2788 			continue;
2789 		}
2790 
2791 		if (entry->bitmap) {
2792 			ret = btrfs_alloc_from_bitmap(block_group,
2793 						      cluster, entry, bytes,
2794 						      cluster->window_start,
2795 						      max_extent_size);
2796 			if (ret == 0) {
2797 				node = rb_next(&entry->offset_index);
2798 				if (!node)
2799 					break;
2800 				entry = rb_entry(node, struct btrfs_free_space,
2801 						 offset_index);
2802 				continue;
2803 			}
2804 			cluster->window_start += bytes;
2805 		} else {
2806 			ret = entry->offset;
2807 
2808 			entry->offset += bytes;
2809 			entry->bytes -= bytes;
2810 		}
2811 
2812 		if (entry->bytes == 0)
2813 			rb_erase(&entry->offset_index, &cluster->root);
2814 		break;
2815 	}
2816 out:
2817 	spin_unlock(&cluster->lock);
2818 
2819 	if (!ret)
2820 		return 0;
2821 
2822 	spin_lock(&ctl->tree_lock);
2823 
2824 	ctl->free_space -= bytes;
2825 	if (entry->bytes == 0) {
2826 		ctl->free_extents--;
2827 		if (entry->bitmap) {
2828 			kmem_cache_free(btrfs_free_space_bitmap_cachep,
2829 					entry->bitmap);
2830 			ctl->total_bitmaps--;
2831 			ctl->op->recalc_thresholds(ctl);
2832 		}
2833 		kmem_cache_free(btrfs_free_space_cachep, entry);
2834 	}
2835 
2836 	spin_unlock(&ctl->tree_lock);
2837 
2838 	return ret;
2839 }
2840 
btrfs_bitmap_cluster(struct btrfs_block_group_cache * block_group,struct btrfs_free_space * entry,struct btrfs_free_cluster * cluster,u64 offset,u64 bytes,u64 cont1_bytes,u64 min_bytes)2841 static int btrfs_bitmap_cluster(struct btrfs_block_group_cache *block_group,
2842 				struct btrfs_free_space *entry,
2843 				struct btrfs_free_cluster *cluster,
2844 				u64 offset, u64 bytes,
2845 				u64 cont1_bytes, u64 min_bytes)
2846 {
2847 	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2848 	unsigned long next_zero;
2849 	unsigned long i;
2850 	unsigned long want_bits;
2851 	unsigned long min_bits;
2852 	unsigned long found_bits;
2853 	unsigned long max_bits = 0;
2854 	unsigned long start = 0;
2855 	unsigned long total_found = 0;
2856 	int ret;
2857 
2858 	i = offset_to_bit(entry->offset, ctl->unit,
2859 			  max_t(u64, offset, entry->offset));
2860 	want_bits = bytes_to_bits(bytes, ctl->unit);
2861 	min_bits = bytes_to_bits(min_bytes, ctl->unit);
2862 
2863 	/*
2864 	 * Don't bother looking for a cluster in this bitmap if it's heavily
2865 	 * fragmented.
2866 	 */
2867 	if (entry->max_extent_size &&
2868 	    entry->max_extent_size < cont1_bytes)
2869 		return -ENOSPC;
2870 again:
2871 	found_bits = 0;
2872 	for_each_set_bit_from(i, entry->bitmap, BITS_PER_BITMAP) {
2873 		next_zero = find_next_zero_bit(entry->bitmap,
2874 					       BITS_PER_BITMAP, i);
2875 		if (next_zero - i >= min_bits) {
2876 			found_bits = next_zero - i;
2877 			if (found_bits > max_bits)
2878 				max_bits = found_bits;
2879 			break;
2880 		}
2881 		if (next_zero - i > max_bits)
2882 			max_bits = next_zero - i;
2883 		i = next_zero;
2884 	}
2885 
2886 	if (!found_bits) {
2887 		entry->max_extent_size = (u64)max_bits * ctl->unit;
2888 		return -ENOSPC;
2889 	}
2890 
2891 	if (!total_found) {
2892 		start = i;
2893 		cluster->max_size = 0;
2894 	}
2895 
2896 	total_found += found_bits;
2897 
2898 	if (cluster->max_size < found_bits * ctl->unit)
2899 		cluster->max_size = found_bits * ctl->unit;
2900 
2901 	if (total_found < want_bits || cluster->max_size < cont1_bytes) {
2902 		i = next_zero + 1;
2903 		goto again;
2904 	}
2905 
2906 	cluster->window_start = start * ctl->unit + entry->offset;
2907 	rb_erase(&entry->offset_index, &ctl->free_space_offset);
2908 	ret = tree_insert_offset(&cluster->root, entry->offset,
2909 				 &entry->offset_index, 1);
2910 	ASSERT(!ret); /* -EEXIST; Logic error */
2911 
2912 	trace_btrfs_setup_cluster(block_group, cluster,
2913 				  total_found * ctl->unit, 1);
2914 	return 0;
2915 }
2916 
2917 /*
2918  * This searches the block group for just extents to fill the cluster with.
2919  * Try to find a cluster with at least bytes total bytes, at least one
2920  * extent of cont1_bytes, and other clusters of at least min_bytes.
2921  */
2922 static noinline int
setup_cluster_no_bitmap(struct btrfs_block_group_cache * block_group,struct btrfs_free_cluster * cluster,struct list_head * bitmaps,u64 offset,u64 bytes,u64 cont1_bytes,u64 min_bytes)2923 setup_cluster_no_bitmap(struct btrfs_block_group_cache *block_group,
2924 			struct btrfs_free_cluster *cluster,
2925 			struct list_head *bitmaps, u64 offset, u64 bytes,
2926 			u64 cont1_bytes, u64 min_bytes)
2927 {
2928 	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
2929 	struct btrfs_free_space *first = NULL;
2930 	struct btrfs_free_space *entry = NULL;
2931 	struct btrfs_free_space *last;
2932 	struct rb_node *node;
2933 	u64 window_free;
2934 	u64 max_extent;
2935 	u64 total_size = 0;
2936 
2937 	entry = tree_search_offset(ctl, offset, 0, 1);
2938 	if (!entry)
2939 		return -ENOSPC;
2940 
2941 	/*
2942 	 * We don't want bitmaps, so just move along until we find a normal
2943 	 * extent entry.
2944 	 */
2945 	while (entry->bitmap || entry->bytes < min_bytes) {
2946 		if (entry->bitmap && list_empty(&entry->list))
2947 			list_add_tail(&entry->list, bitmaps);
2948 		node = rb_next(&entry->offset_index);
2949 		if (!node)
2950 			return -ENOSPC;
2951 		entry = rb_entry(node, struct btrfs_free_space, offset_index);
2952 	}
2953 
2954 	window_free = entry->bytes;
2955 	max_extent = entry->bytes;
2956 	first = entry;
2957 	last = entry;
2958 
2959 	for (node = rb_next(&entry->offset_index); node;
2960 	     node = rb_next(&entry->offset_index)) {
2961 		entry = rb_entry(node, struct btrfs_free_space, offset_index);
2962 
2963 		if (entry->bitmap) {
2964 			if (list_empty(&entry->list))
2965 				list_add_tail(&entry->list, bitmaps);
2966 			continue;
2967 		}
2968 
2969 		if (entry->bytes < min_bytes)
2970 			continue;
2971 
2972 		last = entry;
2973 		window_free += entry->bytes;
2974 		if (entry->bytes > max_extent)
2975 			max_extent = entry->bytes;
2976 	}
2977 
2978 	if (window_free < bytes || max_extent < cont1_bytes)
2979 		return -ENOSPC;
2980 
2981 	cluster->window_start = first->offset;
2982 
2983 	node = &first->offset_index;
2984 
2985 	/*
2986 	 * now we've found our entries, pull them out of the free space
2987 	 * cache and put them into the cluster rbtree
2988 	 */
2989 	do {
2990 		int ret;
2991 
2992 		entry = rb_entry(node, struct btrfs_free_space, offset_index);
2993 		node = rb_next(&entry->offset_index);
2994 		if (entry->bitmap || entry->bytes < min_bytes)
2995 			continue;
2996 
2997 		rb_erase(&entry->offset_index, &ctl->free_space_offset);
2998 		ret = tree_insert_offset(&cluster->root, entry->offset,
2999 					 &entry->offset_index, 0);
3000 		total_size += entry->bytes;
3001 		ASSERT(!ret); /* -EEXIST; Logic error */
3002 	} while (node && entry != last);
3003 
3004 	cluster->max_size = max_extent;
3005 	trace_btrfs_setup_cluster(block_group, cluster, total_size, 0);
3006 	return 0;
3007 }
3008 
3009 /*
3010  * This specifically looks for bitmaps that may work in the cluster, we assume
3011  * that we have already failed to find extents that will work.
3012  */
3013 static noinline int
setup_cluster_bitmap(struct btrfs_block_group_cache * block_group,struct btrfs_free_cluster * cluster,struct list_head * bitmaps,u64 offset,u64 bytes,u64 cont1_bytes,u64 min_bytes)3014 setup_cluster_bitmap(struct btrfs_block_group_cache *block_group,
3015 		     struct btrfs_free_cluster *cluster,
3016 		     struct list_head *bitmaps, u64 offset, u64 bytes,
3017 		     u64 cont1_bytes, u64 min_bytes)
3018 {
3019 	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
3020 	struct btrfs_free_space *entry = NULL;
3021 	int ret = -ENOSPC;
3022 	u64 bitmap_offset = offset_to_bitmap(ctl, offset);
3023 
3024 	if (ctl->total_bitmaps == 0)
3025 		return -ENOSPC;
3026 
3027 	/*
3028 	 * The bitmap that covers offset won't be in the list unless offset
3029 	 * is just its start offset.
3030 	 */
3031 	if (!list_empty(bitmaps))
3032 		entry = list_first_entry(bitmaps, struct btrfs_free_space, list);
3033 
3034 	if (!entry || entry->offset != bitmap_offset) {
3035 		entry = tree_search_offset(ctl, bitmap_offset, 1, 0);
3036 		if (entry && list_empty(&entry->list))
3037 			list_add(&entry->list, bitmaps);
3038 	}
3039 
3040 	list_for_each_entry(entry, bitmaps, list) {
3041 		if (entry->bytes < bytes)
3042 			continue;
3043 		ret = btrfs_bitmap_cluster(block_group, entry, cluster, offset,
3044 					   bytes, cont1_bytes, min_bytes);
3045 		if (!ret)
3046 			return 0;
3047 	}
3048 
3049 	/*
3050 	 * The bitmaps list has all the bitmaps that record free space
3051 	 * starting after offset, so no more search is required.
3052 	 */
3053 	return -ENOSPC;
3054 }
3055 
3056 /*
3057  * here we try to find a cluster of blocks in a block group.  The goal
3058  * is to find at least bytes+empty_size.
3059  * We might not find them all in one contiguous area.
3060  *
3061  * returns zero and sets up cluster if things worked out, otherwise
3062  * it returns -enospc
3063  */
btrfs_find_space_cluster(struct btrfs_block_group_cache * block_group,struct btrfs_free_cluster * cluster,u64 offset,u64 bytes,u64 empty_size)3064 int btrfs_find_space_cluster(struct btrfs_block_group_cache *block_group,
3065 			     struct btrfs_free_cluster *cluster,
3066 			     u64 offset, u64 bytes, u64 empty_size)
3067 {
3068 	struct btrfs_fs_info *fs_info = block_group->fs_info;
3069 	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
3070 	struct btrfs_free_space *entry, *tmp;
3071 	LIST_HEAD(bitmaps);
3072 	u64 min_bytes;
3073 	u64 cont1_bytes;
3074 	int ret;
3075 
3076 	/*
3077 	 * Choose the minimum extent size we'll require for this
3078 	 * cluster.  For SSD_SPREAD, don't allow any fragmentation.
3079 	 * For metadata, allow allocates with smaller extents.  For
3080 	 * data, keep it dense.
3081 	 */
3082 	if (btrfs_test_opt(fs_info, SSD_SPREAD)) {
3083 		cont1_bytes = min_bytes = bytes + empty_size;
3084 	} else if (block_group->flags & BTRFS_BLOCK_GROUP_METADATA) {
3085 		cont1_bytes = bytes;
3086 		min_bytes = fs_info->sectorsize;
3087 	} else {
3088 		cont1_bytes = max(bytes, (bytes + empty_size) >> 2);
3089 		min_bytes = fs_info->sectorsize;
3090 	}
3091 
3092 	spin_lock(&ctl->tree_lock);
3093 
3094 	/*
3095 	 * If we know we don't have enough space to make a cluster don't even
3096 	 * bother doing all the work to try and find one.
3097 	 */
3098 	if (ctl->free_space < bytes) {
3099 		spin_unlock(&ctl->tree_lock);
3100 		return -ENOSPC;
3101 	}
3102 
3103 	spin_lock(&cluster->lock);
3104 
3105 	/* someone already found a cluster, hooray */
3106 	if (cluster->block_group) {
3107 		ret = 0;
3108 		goto out;
3109 	}
3110 
3111 	trace_btrfs_find_cluster(block_group, offset, bytes, empty_size,
3112 				 min_bytes);
3113 
3114 	ret = setup_cluster_no_bitmap(block_group, cluster, &bitmaps, offset,
3115 				      bytes + empty_size,
3116 				      cont1_bytes, min_bytes);
3117 	if (ret)
3118 		ret = setup_cluster_bitmap(block_group, cluster, &bitmaps,
3119 					   offset, bytes + empty_size,
3120 					   cont1_bytes, min_bytes);
3121 
3122 	/* Clear our temporary list */
3123 	list_for_each_entry_safe(entry, tmp, &bitmaps, list)
3124 		list_del_init(&entry->list);
3125 
3126 	if (!ret) {
3127 		atomic_inc(&block_group->count);
3128 		list_add_tail(&cluster->block_group_list,
3129 			      &block_group->cluster_list);
3130 		cluster->block_group = block_group;
3131 	} else {
3132 		trace_btrfs_failed_cluster_setup(block_group);
3133 	}
3134 out:
3135 	spin_unlock(&cluster->lock);
3136 	spin_unlock(&ctl->tree_lock);
3137 
3138 	return ret;
3139 }
3140 
3141 /*
3142  * simple code to zero out a cluster
3143  */
btrfs_init_free_cluster(struct btrfs_free_cluster * cluster)3144 void btrfs_init_free_cluster(struct btrfs_free_cluster *cluster)
3145 {
3146 	spin_lock_init(&cluster->lock);
3147 	spin_lock_init(&cluster->refill_lock);
3148 	cluster->root = RB_ROOT;
3149 	cluster->max_size = 0;
3150 	cluster->fragmented = false;
3151 	INIT_LIST_HEAD(&cluster->block_group_list);
3152 	cluster->block_group = NULL;
3153 }
3154 
do_trimming(struct btrfs_block_group_cache * block_group,u64 * total_trimmed,u64 start,u64 bytes,u64 reserved_start,u64 reserved_bytes,struct btrfs_trim_range * trim_entry)3155 static int do_trimming(struct btrfs_block_group_cache *block_group,
3156 		       u64 *total_trimmed, u64 start, u64 bytes,
3157 		       u64 reserved_start, u64 reserved_bytes,
3158 		       struct btrfs_trim_range *trim_entry)
3159 {
3160 	struct btrfs_space_info *space_info = block_group->space_info;
3161 	struct btrfs_fs_info *fs_info = block_group->fs_info;
3162 	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
3163 	int ret;
3164 	int update = 0;
3165 	u64 trimmed = 0;
3166 
3167 	spin_lock(&space_info->lock);
3168 	spin_lock(&block_group->lock);
3169 	if (!block_group->ro) {
3170 		block_group->reserved += reserved_bytes;
3171 		space_info->bytes_reserved += reserved_bytes;
3172 		update = 1;
3173 	}
3174 	spin_unlock(&block_group->lock);
3175 	spin_unlock(&space_info->lock);
3176 
3177 	ret = btrfs_discard_extent(fs_info, start, bytes, &trimmed);
3178 	if (!ret)
3179 		*total_trimmed += trimmed;
3180 
3181 	mutex_lock(&ctl->cache_writeout_mutex);
3182 	btrfs_add_free_space(block_group, reserved_start, reserved_bytes);
3183 	list_del(&trim_entry->list);
3184 	mutex_unlock(&ctl->cache_writeout_mutex);
3185 
3186 	if (update) {
3187 		spin_lock(&space_info->lock);
3188 		spin_lock(&block_group->lock);
3189 		if (block_group->ro)
3190 			space_info->bytes_readonly += reserved_bytes;
3191 		block_group->reserved -= reserved_bytes;
3192 		space_info->bytes_reserved -= reserved_bytes;
3193 		spin_unlock(&block_group->lock);
3194 		spin_unlock(&space_info->lock);
3195 	}
3196 
3197 	return ret;
3198 }
3199 
trim_no_bitmap(struct btrfs_block_group_cache * block_group,u64 * total_trimmed,u64 start,u64 end,u64 minlen)3200 static int trim_no_bitmap(struct btrfs_block_group_cache *block_group,
3201 			  u64 *total_trimmed, u64 start, u64 end, u64 minlen)
3202 {
3203 	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
3204 	struct btrfs_free_space *entry;
3205 	struct rb_node *node;
3206 	int ret = 0;
3207 	u64 extent_start;
3208 	u64 extent_bytes;
3209 	u64 bytes;
3210 
3211 	while (start < end) {
3212 		struct btrfs_trim_range trim_entry;
3213 
3214 		mutex_lock(&ctl->cache_writeout_mutex);
3215 		spin_lock(&ctl->tree_lock);
3216 
3217 		if (ctl->free_space < minlen) {
3218 			spin_unlock(&ctl->tree_lock);
3219 			mutex_unlock(&ctl->cache_writeout_mutex);
3220 			break;
3221 		}
3222 
3223 		entry = tree_search_offset(ctl, start, 0, 1);
3224 		if (!entry) {
3225 			spin_unlock(&ctl->tree_lock);
3226 			mutex_unlock(&ctl->cache_writeout_mutex);
3227 			break;
3228 		}
3229 
3230 		/* skip bitmaps */
3231 		while (entry->bitmap) {
3232 			node = rb_next(&entry->offset_index);
3233 			if (!node) {
3234 				spin_unlock(&ctl->tree_lock);
3235 				mutex_unlock(&ctl->cache_writeout_mutex);
3236 				goto out;
3237 			}
3238 			entry = rb_entry(node, struct btrfs_free_space,
3239 					 offset_index);
3240 		}
3241 
3242 		if (entry->offset >= end) {
3243 			spin_unlock(&ctl->tree_lock);
3244 			mutex_unlock(&ctl->cache_writeout_mutex);
3245 			break;
3246 		}
3247 
3248 		extent_start = entry->offset;
3249 		extent_bytes = entry->bytes;
3250 		start = max(start, extent_start);
3251 		bytes = min(extent_start + extent_bytes, end) - start;
3252 		if (bytes < minlen) {
3253 			spin_unlock(&ctl->tree_lock);
3254 			mutex_unlock(&ctl->cache_writeout_mutex);
3255 			goto next;
3256 		}
3257 
3258 		unlink_free_space(ctl, entry);
3259 		kmem_cache_free(btrfs_free_space_cachep, entry);
3260 
3261 		spin_unlock(&ctl->tree_lock);
3262 		trim_entry.start = extent_start;
3263 		trim_entry.bytes = extent_bytes;
3264 		list_add_tail(&trim_entry.list, &ctl->trimming_ranges);
3265 		mutex_unlock(&ctl->cache_writeout_mutex);
3266 
3267 		ret = do_trimming(block_group, total_trimmed, start, bytes,
3268 				  extent_start, extent_bytes, &trim_entry);
3269 		if (ret)
3270 			break;
3271 next:
3272 		start += bytes;
3273 
3274 		if (fatal_signal_pending(current)) {
3275 			ret = -ERESTARTSYS;
3276 			break;
3277 		}
3278 
3279 		cond_resched();
3280 	}
3281 out:
3282 	return ret;
3283 }
3284 
trim_bitmaps(struct btrfs_block_group_cache * block_group,u64 * total_trimmed,u64 start,u64 end,u64 minlen)3285 static int trim_bitmaps(struct btrfs_block_group_cache *block_group,
3286 			u64 *total_trimmed, u64 start, u64 end, u64 minlen)
3287 {
3288 	struct btrfs_free_space_ctl *ctl = block_group->free_space_ctl;
3289 	struct btrfs_free_space *entry;
3290 	int ret = 0;
3291 	int ret2;
3292 	u64 bytes;
3293 	u64 offset = offset_to_bitmap(ctl, start);
3294 
3295 	while (offset < end) {
3296 		bool next_bitmap = false;
3297 		struct btrfs_trim_range trim_entry;
3298 
3299 		mutex_lock(&ctl->cache_writeout_mutex);
3300 		spin_lock(&ctl->tree_lock);
3301 
3302 		if (ctl->free_space < minlen) {
3303 			spin_unlock(&ctl->tree_lock);
3304 			mutex_unlock(&ctl->cache_writeout_mutex);
3305 			break;
3306 		}
3307 
3308 		entry = tree_search_offset(ctl, offset, 1, 0);
3309 		if (!entry) {
3310 			spin_unlock(&ctl->tree_lock);
3311 			mutex_unlock(&ctl->cache_writeout_mutex);
3312 			next_bitmap = true;
3313 			goto next;
3314 		}
3315 
3316 		bytes = minlen;
3317 		ret2 = search_bitmap(ctl, entry, &start, &bytes, false);
3318 		if (ret2 || start >= end) {
3319 			spin_unlock(&ctl->tree_lock);
3320 			mutex_unlock(&ctl->cache_writeout_mutex);
3321 			next_bitmap = true;
3322 			goto next;
3323 		}
3324 
3325 		bytes = min(bytes, end - start);
3326 		if (bytes < minlen) {
3327 			spin_unlock(&ctl->tree_lock);
3328 			mutex_unlock(&ctl->cache_writeout_mutex);
3329 			goto next;
3330 		}
3331 
3332 		bitmap_clear_bits(ctl, entry, start, bytes);
3333 		if (entry->bytes == 0)
3334 			free_bitmap(ctl, entry);
3335 
3336 		spin_unlock(&ctl->tree_lock);
3337 		trim_entry.start = start;
3338 		trim_entry.bytes = bytes;
3339 		list_add_tail(&trim_entry.list, &ctl->trimming_ranges);
3340 		mutex_unlock(&ctl->cache_writeout_mutex);
3341 
3342 		ret = do_trimming(block_group, total_trimmed, start, bytes,
3343 				  start, bytes, &trim_entry);
3344 		if (ret)
3345 			break;
3346 next:
3347 		if (next_bitmap) {
3348 			offset += BITS_PER_BITMAP * ctl->unit;
3349 		} else {
3350 			start += bytes;
3351 			if (start >= offset + BITS_PER_BITMAP * ctl->unit)
3352 				offset += BITS_PER_BITMAP * ctl->unit;
3353 		}
3354 
3355 		if (fatal_signal_pending(current)) {
3356 			ret = -ERESTARTSYS;
3357 			break;
3358 		}
3359 
3360 		cond_resched();
3361 	}
3362 
3363 	return ret;
3364 }
3365 
btrfs_get_block_group_trimming(struct btrfs_block_group_cache * cache)3366 void btrfs_get_block_group_trimming(struct btrfs_block_group_cache *cache)
3367 {
3368 	atomic_inc(&cache->trimming);
3369 }
3370 
btrfs_put_block_group_trimming(struct btrfs_block_group_cache * block_group)3371 void btrfs_put_block_group_trimming(struct btrfs_block_group_cache *block_group)
3372 {
3373 	struct btrfs_fs_info *fs_info = block_group->fs_info;
3374 	struct extent_map_tree *em_tree;
3375 	struct extent_map *em;
3376 	bool cleanup;
3377 
3378 	spin_lock(&block_group->lock);
3379 	cleanup = (atomic_dec_and_test(&block_group->trimming) &&
3380 		   block_group->removed);
3381 	spin_unlock(&block_group->lock);
3382 
3383 	if (cleanup) {
3384 		mutex_lock(&fs_info->chunk_mutex);
3385 		em_tree = &fs_info->mapping_tree;
3386 		write_lock(&em_tree->lock);
3387 		em = lookup_extent_mapping(em_tree, block_group->key.objectid,
3388 					   1);
3389 		BUG_ON(!em); /* logic error, can't happen */
3390 		remove_extent_mapping(em_tree, em);
3391 		write_unlock(&em_tree->lock);
3392 		mutex_unlock(&fs_info->chunk_mutex);
3393 
3394 		/* once for us and once for the tree */
3395 		free_extent_map(em);
3396 		free_extent_map(em);
3397 
3398 		/*
3399 		 * We've left one free space entry and other tasks trimming
3400 		 * this block group have left 1 entry each one. Free them.
3401 		 */
3402 		__btrfs_remove_free_space_cache(block_group->free_space_ctl);
3403 	}
3404 }
3405 
btrfs_trim_block_group(struct btrfs_block_group_cache * block_group,u64 * trimmed,u64 start,u64 end,u64 minlen)3406 int btrfs_trim_block_group(struct btrfs_block_group_cache *block_group,
3407 			   u64 *trimmed, u64 start, u64 end, u64 minlen)
3408 {
3409 	int ret;
3410 
3411 	*trimmed = 0;
3412 
3413 	spin_lock(&block_group->lock);
3414 	if (block_group->removed) {
3415 		spin_unlock(&block_group->lock);
3416 		return 0;
3417 	}
3418 	btrfs_get_block_group_trimming(block_group);
3419 	spin_unlock(&block_group->lock);
3420 
3421 	ret = trim_no_bitmap(block_group, trimmed, start, end, minlen);
3422 	if (ret)
3423 		goto out;
3424 
3425 	ret = trim_bitmaps(block_group, trimmed, start, end, minlen);
3426 out:
3427 	btrfs_put_block_group_trimming(block_group);
3428 	return ret;
3429 }
3430 
3431 /*
3432  * Find the left-most item in the cache tree, and then return the
3433  * smallest inode number in the item.
3434  *
3435  * Note: the returned inode number may not be the smallest one in
3436  * the tree, if the left-most item is a bitmap.
3437  */
btrfs_find_ino_for_alloc(struct btrfs_root * fs_root)3438 u64 btrfs_find_ino_for_alloc(struct btrfs_root *fs_root)
3439 {
3440 	struct btrfs_free_space_ctl *ctl = fs_root->free_ino_ctl;
3441 	struct btrfs_free_space *entry = NULL;
3442 	u64 ino = 0;
3443 
3444 	spin_lock(&ctl->tree_lock);
3445 
3446 	if (RB_EMPTY_ROOT(&ctl->free_space_offset))
3447 		goto out;
3448 
3449 	entry = rb_entry(rb_first(&ctl->free_space_offset),
3450 			 struct btrfs_free_space, offset_index);
3451 
3452 	if (!entry->bitmap) {
3453 		ino = entry->offset;
3454 
3455 		unlink_free_space(ctl, entry);
3456 		entry->offset++;
3457 		entry->bytes--;
3458 		if (!entry->bytes)
3459 			kmem_cache_free(btrfs_free_space_cachep, entry);
3460 		else
3461 			link_free_space(ctl, entry);
3462 	} else {
3463 		u64 offset = 0;
3464 		u64 count = 1;
3465 		int ret;
3466 
3467 		ret = search_bitmap(ctl, entry, &offset, &count, true);
3468 		/* Logic error; Should be empty if it can't find anything */
3469 		ASSERT(!ret);
3470 
3471 		ino = offset;
3472 		bitmap_clear_bits(ctl, entry, offset, 1);
3473 		if (entry->bytes == 0)
3474 			free_bitmap(ctl, entry);
3475 	}
3476 out:
3477 	spin_unlock(&ctl->tree_lock);
3478 
3479 	return ino;
3480 }
3481 
lookup_free_ino_inode(struct btrfs_root * root,struct btrfs_path * path)3482 struct inode *lookup_free_ino_inode(struct btrfs_root *root,
3483 				    struct btrfs_path *path)
3484 {
3485 	struct inode *inode = NULL;
3486 
3487 	spin_lock(&root->ino_cache_lock);
3488 	if (root->ino_cache_inode)
3489 		inode = igrab(root->ino_cache_inode);
3490 	spin_unlock(&root->ino_cache_lock);
3491 	if (inode)
3492 		return inode;
3493 
3494 	inode = __lookup_free_space_inode(root, path, 0);
3495 	if (IS_ERR(inode))
3496 		return inode;
3497 
3498 	spin_lock(&root->ino_cache_lock);
3499 	if (!btrfs_fs_closing(root->fs_info))
3500 		root->ino_cache_inode = igrab(inode);
3501 	spin_unlock(&root->ino_cache_lock);
3502 
3503 	return inode;
3504 }
3505 
create_free_ino_inode(struct btrfs_root * root,struct btrfs_trans_handle * trans,struct btrfs_path * path)3506 int create_free_ino_inode(struct btrfs_root *root,
3507 			  struct btrfs_trans_handle *trans,
3508 			  struct btrfs_path *path)
3509 {
3510 	return __create_free_space_inode(root, trans, path,
3511 					 BTRFS_FREE_INO_OBJECTID, 0);
3512 }
3513 
load_free_ino_cache(struct btrfs_fs_info * fs_info,struct btrfs_root * root)3514 int load_free_ino_cache(struct btrfs_fs_info *fs_info, struct btrfs_root *root)
3515 {
3516 	struct btrfs_free_space_ctl *ctl = root->free_ino_ctl;
3517 	struct btrfs_path *path;
3518 	struct inode *inode;
3519 	int ret = 0;
3520 	u64 root_gen = btrfs_root_generation(&root->root_item);
3521 
3522 	if (!btrfs_test_opt(fs_info, INODE_MAP_CACHE))
3523 		return 0;
3524 
3525 	/*
3526 	 * If we're unmounting then just return, since this does a search on the
3527 	 * normal root and not the commit root and we could deadlock.
3528 	 */
3529 	if (btrfs_fs_closing(fs_info))
3530 		return 0;
3531 
3532 	path = btrfs_alloc_path();
3533 	if (!path)
3534 		return 0;
3535 
3536 	inode = lookup_free_ino_inode(root, path);
3537 	if (IS_ERR(inode))
3538 		goto out;
3539 
3540 	if (root_gen != BTRFS_I(inode)->generation)
3541 		goto out_put;
3542 
3543 	ret = __load_free_space_cache(root, inode, ctl, path, 0);
3544 
3545 	if (ret < 0)
3546 		btrfs_err(fs_info,
3547 			"failed to load free ino cache for root %llu",
3548 			root->root_key.objectid);
3549 out_put:
3550 	iput(inode);
3551 out:
3552 	btrfs_free_path(path);
3553 	return ret;
3554 }
3555 
btrfs_write_out_ino_cache(struct btrfs_root * root,struct btrfs_trans_handle * trans,struct btrfs_path * path,struct inode * inode)3556 int btrfs_write_out_ino_cache(struct btrfs_root *root,
3557 			      struct btrfs_trans_handle *trans,
3558 			      struct btrfs_path *path,
3559 			      struct inode *inode)
3560 {
3561 	struct btrfs_fs_info *fs_info = root->fs_info;
3562 	struct btrfs_free_space_ctl *ctl = root->free_ino_ctl;
3563 	int ret;
3564 	struct btrfs_io_ctl io_ctl;
3565 	bool release_metadata = true;
3566 
3567 	if (!btrfs_test_opt(fs_info, INODE_MAP_CACHE))
3568 		return 0;
3569 
3570 	memset(&io_ctl, 0, sizeof(io_ctl));
3571 	ret = __btrfs_write_out_cache(root, inode, ctl, NULL, &io_ctl, trans);
3572 	if (!ret) {
3573 		/*
3574 		 * At this point writepages() didn't error out, so our metadata
3575 		 * reservation is released when the writeback finishes, at
3576 		 * inode.c:btrfs_finish_ordered_io(), regardless of it finishing
3577 		 * with or without an error.
3578 		 */
3579 		release_metadata = false;
3580 		ret = btrfs_wait_cache_io_root(root, trans, &io_ctl, path);
3581 	}
3582 
3583 	if (ret) {
3584 		if (release_metadata)
3585 			btrfs_delalloc_release_metadata(BTRFS_I(inode),
3586 					inode->i_size, true);
3587 #ifdef DEBUG
3588 		btrfs_err(fs_info,
3589 			  "failed to write free ino cache for root %llu",
3590 			  root->root_key.objectid);
3591 #endif
3592 	}
3593 
3594 	return ret;
3595 }
3596 
3597 #ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
3598 /*
3599  * Use this if you need to make a bitmap or extent entry specifically, it
3600  * doesn't do any of the merging that add_free_space does, this acts a lot like
3601  * how the free space cache loading stuff works, so you can get really weird
3602  * configurations.
3603  */
test_add_free_space_entry(struct btrfs_block_group_cache * cache,u64 offset,u64 bytes,bool bitmap)3604 int test_add_free_space_entry(struct btrfs_block_group_cache *cache,
3605 			      u64 offset, u64 bytes, bool bitmap)
3606 {
3607 	struct btrfs_free_space_ctl *ctl = cache->free_space_ctl;
3608 	struct btrfs_free_space *info = NULL, *bitmap_info;
3609 	void *map = NULL;
3610 	u64 bytes_added;
3611 	int ret;
3612 
3613 again:
3614 	if (!info) {
3615 		info = kmem_cache_zalloc(btrfs_free_space_cachep, GFP_NOFS);
3616 		if (!info)
3617 			return -ENOMEM;
3618 	}
3619 
3620 	if (!bitmap) {
3621 		spin_lock(&ctl->tree_lock);
3622 		info->offset = offset;
3623 		info->bytes = bytes;
3624 		info->max_extent_size = 0;
3625 		ret = link_free_space(ctl, info);
3626 		spin_unlock(&ctl->tree_lock);
3627 		if (ret)
3628 			kmem_cache_free(btrfs_free_space_cachep, info);
3629 		return ret;
3630 	}
3631 
3632 	if (!map) {
3633 		map = kmem_cache_zalloc(btrfs_free_space_bitmap_cachep, GFP_NOFS);
3634 		if (!map) {
3635 			kmem_cache_free(btrfs_free_space_cachep, info);
3636 			return -ENOMEM;
3637 		}
3638 	}
3639 
3640 	spin_lock(&ctl->tree_lock);
3641 	bitmap_info = tree_search_offset(ctl, offset_to_bitmap(ctl, offset),
3642 					 1, 0);
3643 	if (!bitmap_info) {
3644 		info->bitmap = map;
3645 		map = NULL;
3646 		add_new_bitmap(ctl, info, offset);
3647 		bitmap_info = info;
3648 		info = NULL;
3649 	}
3650 
3651 	bytes_added = add_bytes_to_bitmap(ctl, bitmap_info, offset, bytes);
3652 
3653 	bytes -= bytes_added;
3654 	offset += bytes_added;
3655 	spin_unlock(&ctl->tree_lock);
3656 
3657 	if (bytes)
3658 		goto again;
3659 
3660 	if (info)
3661 		kmem_cache_free(btrfs_free_space_cachep, info);
3662 	if (map)
3663 		kmem_cache_free(btrfs_free_space_bitmap_cachep, map);
3664 	return 0;
3665 }
3666 
3667 /*
3668  * Checks to see if the given range is in the free space cache.  This is really
3669  * just used to check the absence of space, so if there is free space in the
3670  * range at all we will return 1.
3671  */
test_check_exists(struct btrfs_block_group_cache * cache,u64 offset,u64 bytes)3672 int test_check_exists(struct btrfs_block_group_cache *cache,
3673 		      u64 offset, u64 bytes)
3674 {
3675 	struct btrfs_free_space_ctl *ctl = cache->free_space_ctl;
3676 	struct btrfs_free_space *info;
3677 	int ret = 0;
3678 
3679 	spin_lock(&ctl->tree_lock);
3680 	info = tree_search_offset(ctl, offset, 0, 0);
3681 	if (!info) {
3682 		info = tree_search_offset(ctl, offset_to_bitmap(ctl, offset),
3683 					  1, 0);
3684 		if (!info)
3685 			goto out;
3686 	}
3687 
3688 have_info:
3689 	if (info->bitmap) {
3690 		u64 bit_off, bit_bytes;
3691 		struct rb_node *n;
3692 		struct btrfs_free_space *tmp;
3693 
3694 		bit_off = offset;
3695 		bit_bytes = ctl->unit;
3696 		ret = search_bitmap(ctl, info, &bit_off, &bit_bytes, false);
3697 		if (!ret) {
3698 			if (bit_off == offset) {
3699 				ret = 1;
3700 				goto out;
3701 			} else if (bit_off > offset &&
3702 				   offset + bytes > bit_off) {
3703 				ret = 1;
3704 				goto out;
3705 			}
3706 		}
3707 
3708 		n = rb_prev(&info->offset_index);
3709 		while (n) {
3710 			tmp = rb_entry(n, struct btrfs_free_space,
3711 				       offset_index);
3712 			if (tmp->offset + tmp->bytes < offset)
3713 				break;
3714 			if (offset + bytes < tmp->offset) {
3715 				n = rb_prev(&tmp->offset_index);
3716 				continue;
3717 			}
3718 			info = tmp;
3719 			goto have_info;
3720 		}
3721 
3722 		n = rb_next(&info->offset_index);
3723 		while (n) {
3724 			tmp = rb_entry(n, struct btrfs_free_space,
3725 				       offset_index);
3726 			if (offset + bytes < tmp->offset)
3727 				break;
3728 			if (tmp->offset + tmp->bytes < offset) {
3729 				n = rb_next(&tmp->offset_index);
3730 				continue;
3731 			}
3732 			info = tmp;
3733 			goto have_info;
3734 		}
3735 
3736 		ret = 0;
3737 		goto out;
3738 	}
3739 
3740 	if (info->offset == offset) {
3741 		ret = 1;
3742 		goto out;
3743 	}
3744 
3745 	if (offset > info->offset && offset < info->offset + info->bytes)
3746 		ret = 1;
3747 out:
3748 	spin_unlock(&ctl->tree_lock);
3749 	return ret;
3750 }
3751 #endif /* CONFIG_BTRFS_FS_RUN_SANITY_TESTS */
3752