xref: /openbmc/linux/fs/btrfs/disk-io.c (revision ef97e774)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Copyright (C) 2007 Oracle.  All rights reserved.
4  */
5 
6 #include <linux/fs.h>
7 #include <linux/blkdev.h>
8 #include <linux/radix-tree.h>
9 #include <linux/writeback.h>
10 #include <linux/workqueue.h>
11 #include <linux/kthread.h>
12 #include <linux/slab.h>
13 #include <linux/migrate.h>
14 #include <linux/ratelimit.h>
15 #include <linux/uuid.h>
16 #include <linux/semaphore.h>
17 #include <linux/error-injection.h>
18 #include <linux/crc32c.h>
19 #include <linux/sched/mm.h>
20 #include <asm/unaligned.h>
21 #include <crypto/hash.h>
22 #include "ctree.h"
23 #include "disk-io.h"
24 #include "transaction.h"
25 #include "btrfs_inode.h"
26 #include "bio.h"
27 #include "print-tree.h"
28 #include "locking.h"
29 #include "tree-log.h"
30 #include "free-space-cache.h"
31 #include "free-space-tree.h"
32 #include "check-integrity.h"
33 #include "rcu-string.h"
34 #include "dev-replace.h"
35 #include "raid56.h"
36 #include "sysfs.h"
37 #include "qgroup.h"
38 #include "compression.h"
39 #include "tree-checker.h"
40 #include "ref-verify.h"
41 #include "block-group.h"
42 #include "discard.h"
43 #include "space-info.h"
44 #include "zoned.h"
45 #include "subpage.h"
46 #include "fs.h"
47 #include "accessors.h"
48 #include "extent-tree.h"
49 #include "root-tree.h"
50 #include "defrag.h"
51 #include "uuid-tree.h"
52 #include "relocation.h"
53 #include "scrub.h"
54 #include "super.h"
55 
56 #define BTRFS_SUPER_FLAG_SUPP	(BTRFS_HEADER_FLAG_WRITTEN |\
57 				 BTRFS_HEADER_FLAG_RELOC |\
58 				 BTRFS_SUPER_FLAG_ERROR |\
59 				 BTRFS_SUPER_FLAG_SEEDING |\
60 				 BTRFS_SUPER_FLAG_METADUMP |\
61 				 BTRFS_SUPER_FLAG_METADUMP_V2)
62 
63 static void btrfs_destroy_ordered_extents(struct btrfs_root *root);
64 static int btrfs_destroy_delayed_refs(struct btrfs_transaction *trans,
65 				      struct btrfs_fs_info *fs_info);
66 static void btrfs_destroy_delalloc_inodes(struct btrfs_root *root);
67 static int btrfs_destroy_marked_extents(struct btrfs_fs_info *fs_info,
68 					struct extent_io_tree *dirty_pages,
69 					int mark);
70 static int btrfs_destroy_pinned_extent(struct btrfs_fs_info *fs_info,
71 				       struct extent_io_tree *pinned_extents);
72 static int btrfs_cleanup_transaction(struct btrfs_fs_info *fs_info);
73 static void btrfs_error_commit_super(struct btrfs_fs_info *fs_info);
74 
75 static void btrfs_free_csum_hash(struct btrfs_fs_info *fs_info)
76 {
77 	if (fs_info->csum_shash)
78 		crypto_free_shash(fs_info->csum_shash);
79 }
80 
81 /*
82  * Compute the csum of a btree block and store the result to provided buffer.
83  */
84 static void csum_tree_block(struct extent_buffer *buf, u8 *result)
85 {
86 	struct btrfs_fs_info *fs_info = buf->fs_info;
87 	const int num_pages = num_extent_pages(buf);
88 	const int first_page_part = min_t(u32, PAGE_SIZE, fs_info->nodesize);
89 	SHASH_DESC_ON_STACK(shash, fs_info->csum_shash);
90 	char *kaddr;
91 	int i;
92 
93 	shash->tfm = fs_info->csum_shash;
94 	crypto_shash_init(shash);
95 	kaddr = page_address(buf->pages[0]) + offset_in_page(buf->start);
96 	crypto_shash_update(shash, kaddr + BTRFS_CSUM_SIZE,
97 			    first_page_part - BTRFS_CSUM_SIZE);
98 
99 	for (i = 1; i < num_pages; i++) {
100 		kaddr = page_address(buf->pages[i]);
101 		crypto_shash_update(shash, kaddr, PAGE_SIZE);
102 	}
103 	memset(result, 0, BTRFS_CSUM_SIZE);
104 	crypto_shash_final(shash, result);
105 }
106 
107 /*
108  * we can't consider a given block up to date unless the transid of the
109  * block matches the transid in the parent node's pointer.  This is how we
110  * detect blocks that either didn't get written at all or got written
111  * in the wrong place.
112  */
113 static int verify_parent_transid(struct extent_io_tree *io_tree,
114 				 struct extent_buffer *eb, u64 parent_transid,
115 				 int atomic)
116 {
117 	struct extent_state *cached_state = NULL;
118 	int ret;
119 
120 	if (!parent_transid || btrfs_header_generation(eb) == parent_transid)
121 		return 0;
122 
123 	if (atomic)
124 		return -EAGAIN;
125 
126 	lock_extent(io_tree, eb->start, eb->start + eb->len - 1, &cached_state);
127 	if (extent_buffer_uptodate(eb) &&
128 	    btrfs_header_generation(eb) == parent_transid) {
129 		ret = 0;
130 		goto out;
131 	}
132 	btrfs_err_rl(eb->fs_info,
133 "parent transid verify failed on logical %llu mirror %u wanted %llu found %llu",
134 			eb->start, eb->read_mirror,
135 			parent_transid, btrfs_header_generation(eb));
136 	ret = 1;
137 	clear_extent_buffer_uptodate(eb);
138 out:
139 	unlock_extent(io_tree, eb->start, eb->start + eb->len - 1,
140 		      &cached_state);
141 	return ret;
142 }
143 
144 static bool btrfs_supported_super_csum(u16 csum_type)
145 {
146 	switch (csum_type) {
147 	case BTRFS_CSUM_TYPE_CRC32:
148 	case BTRFS_CSUM_TYPE_XXHASH:
149 	case BTRFS_CSUM_TYPE_SHA256:
150 	case BTRFS_CSUM_TYPE_BLAKE2:
151 		return true;
152 	default:
153 		return false;
154 	}
155 }
156 
157 /*
158  * Return 0 if the superblock checksum type matches the checksum value of that
159  * algorithm. Pass the raw disk superblock data.
160  */
161 int btrfs_check_super_csum(struct btrfs_fs_info *fs_info,
162 			   const struct btrfs_super_block *disk_sb)
163 {
164 	char result[BTRFS_CSUM_SIZE];
165 	SHASH_DESC_ON_STACK(shash, fs_info->csum_shash);
166 
167 	shash->tfm = fs_info->csum_shash;
168 
169 	/*
170 	 * The super_block structure does not span the whole
171 	 * BTRFS_SUPER_INFO_SIZE range, we expect that the unused space is
172 	 * filled with zeros and is included in the checksum.
173 	 */
174 	crypto_shash_digest(shash, (const u8 *)disk_sb + BTRFS_CSUM_SIZE,
175 			    BTRFS_SUPER_INFO_SIZE - BTRFS_CSUM_SIZE, result);
176 
177 	if (memcmp(disk_sb->csum, result, fs_info->csum_size))
178 		return 1;
179 
180 	return 0;
181 }
182 
183 int btrfs_verify_level_key(struct extent_buffer *eb, int level,
184 			   struct btrfs_key *first_key, u64 parent_transid)
185 {
186 	struct btrfs_fs_info *fs_info = eb->fs_info;
187 	int found_level;
188 	struct btrfs_key found_key;
189 	int ret;
190 
191 	found_level = btrfs_header_level(eb);
192 	if (found_level != level) {
193 		WARN(IS_ENABLED(CONFIG_BTRFS_DEBUG),
194 		     KERN_ERR "BTRFS: tree level check failed\n");
195 		btrfs_err(fs_info,
196 "tree level mismatch detected, bytenr=%llu level expected=%u has=%u",
197 			  eb->start, level, found_level);
198 		return -EIO;
199 	}
200 
201 	if (!first_key)
202 		return 0;
203 
204 	/*
205 	 * For live tree block (new tree blocks in current transaction),
206 	 * we need proper lock context to avoid race, which is impossible here.
207 	 * So we only checks tree blocks which is read from disk, whose
208 	 * generation <= fs_info->last_trans_committed.
209 	 */
210 	if (btrfs_header_generation(eb) > fs_info->last_trans_committed)
211 		return 0;
212 
213 	/* We have @first_key, so this @eb must have at least one item */
214 	if (btrfs_header_nritems(eb) == 0) {
215 		btrfs_err(fs_info,
216 		"invalid tree nritems, bytenr=%llu nritems=0 expect >0",
217 			  eb->start);
218 		WARN_ON(IS_ENABLED(CONFIG_BTRFS_DEBUG));
219 		return -EUCLEAN;
220 	}
221 
222 	if (found_level)
223 		btrfs_node_key_to_cpu(eb, &found_key, 0);
224 	else
225 		btrfs_item_key_to_cpu(eb, &found_key, 0);
226 	ret = btrfs_comp_cpu_keys(first_key, &found_key);
227 
228 	if (ret) {
229 		WARN(IS_ENABLED(CONFIG_BTRFS_DEBUG),
230 		     KERN_ERR "BTRFS: tree first key check failed\n");
231 		btrfs_err(fs_info,
232 "tree first key mismatch detected, bytenr=%llu parent_transid=%llu key expected=(%llu,%u,%llu) has=(%llu,%u,%llu)",
233 			  eb->start, parent_transid, first_key->objectid,
234 			  first_key->type, first_key->offset,
235 			  found_key.objectid, found_key.type,
236 			  found_key.offset);
237 	}
238 	return ret;
239 }
240 
241 static int btrfs_repair_eb_io_failure(const struct extent_buffer *eb,
242 				      int mirror_num)
243 {
244 	struct btrfs_fs_info *fs_info = eb->fs_info;
245 	u64 start = eb->start;
246 	int i, num_pages = num_extent_pages(eb);
247 	int ret = 0;
248 
249 	if (sb_rdonly(fs_info->sb))
250 		return -EROFS;
251 
252 	for (i = 0; i < num_pages; i++) {
253 		struct page *p = eb->pages[i];
254 
255 		ret = btrfs_repair_io_failure(fs_info, 0, start, PAGE_SIZE,
256 				start, p, start - page_offset(p), mirror_num);
257 		if (ret)
258 			break;
259 		start += PAGE_SIZE;
260 	}
261 
262 	return ret;
263 }
264 
265 /*
266  * helper to read a given tree block, doing retries as required when
267  * the checksums don't match and we have alternate mirrors to try.
268  *
269  * @check:		expected tree parentness check, see the comments of the
270  *			structure for details.
271  */
272 int btrfs_read_extent_buffer(struct extent_buffer *eb,
273 			     struct btrfs_tree_parent_check *check)
274 {
275 	struct btrfs_fs_info *fs_info = eb->fs_info;
276 	int failed = 0;
277 	int ret;
278 	int num_copies = 0;
279 	int mirror_num = 0;
280 	int failed_mirror = 0;
281 
282 	ASSERT(check);
283 
284 	while (1) {
285 		clear_bit(EXTENT_BUFFER_CORRUPT, &eb->bflags);
286 		ret = read_extent_buffer_pages(eb, WAIT_COMPLETE, mirror_num, check);
287 		if (!ret)
288 			break;
289 
290 		num_copies = btrfs_num_copies(fs_info,
291 					      eb->start, eb->len);
292 		if (num_copies == 1)
293 			break;
294 
295 		if (!failed_mirror) {
296 			failed = 1;
297 			failed_mirror = eb->read_mirror;
298 		}
299 
300 		mirror_num++;
301 		if (mirror_num == failed_mirror)
302 			mirror_num++;
303 
304 		if (mirror_num > num_copies)
305 			break;
306 	}
307 
308 	if (failed && !ret && failed_mirror)
309 		btrfs_repair_eb_io_failure(eb, failed_mirror);
310 
311 	return ret;
312 }
313 
314 static int csum_one_extent_buffer(struct extent_buffer *eb)
315 {
316 	struct btrfs_fs_info *fs_info = eb->fs_info;
317 	u8 result[BTRFS_CSUM_SIZE];
318 	int ret;
319 
320 	ASSERT(memcmp_extent_buffer(eb, fs_info->fs_devices->metadata_uuid,
321 				    offsetof(struct btrfs_header, fsid),
322 				    BTRFS_FSID_SIZE) == 0);
323 	csum_tree_block(eb, result);
324 
325 	if (btrfs_header_level(eb))
326 		ret = btrfs_check_node(eb);
327 	else
328 		ret = btrfs_check_leaf_full(eb);
329 
330 	if (ret < 0)
331 		goto error;
332 
333 	/*
334 	 * Also check the generation, the eb reached here must be newer than
335 	 * last committed. Or something seriously wrong happened.
336 	 */
337 	if (unlikely(btrfs_header_generation(eb) <= fs_info->last_trans_committed)) {
338 		ret = -EUCLEAN;
339 		btrfs_err(fs_info,
340 			"block=%llu bad generation, have %llu expect > %llu",
341 			  eb->start, btrfs_header_generation(eb),
342 			  fs_info->last_trans_committed);
343 		goto error;
344 	}
345 	write_extent_buffer(eb, result, 0, fs_info->csum_size);
346 
347 	return 0;
348 
349 error:
350 	btrfs_print_tree(eb, 0);
351 	btrfs_err(fs_info, "block=%llu write time tree block corruption detected",
352 		  eb->start);
353 	/*
354 	 * Be noisy if this is an extent buffer from a log tree. We don't abort
355 	 * a transaction in case there's a bad log tree extent buffer, we just
356 	 * fallback to a transaction commit. Still we want to know when there is
357 	 * a bad log tree extent buffer, as that may signal a bug somewhere.
358 	 */
359 	WARN_ON(IS_ENABLED(CONFIG_BTRFS_DEBUG) ||
360 		btrfs_header_owner(eb) == BTRFS_TREE_LOG_OBJECTID);
361 	return ret;
362 }
363 
364 /* Checksum all dirty extent buffers in one bio_vec */
365 static int csum_dirty_subpage_buffers(struct btrfs_fs_info *fs_info,
366 				      struct bio_vec *bvec)
367 {
368 	struct page *page = bvec->bv_page;
369 	u64 bvec_start = page_offset(page) + bvec->bv_offset;
370 	u64 cur;
371 	int ret = 0;
372 
373 	for (cur = bvec_start; cur < bvec_start + bvec->bv_len;
374 	     cur += fs_info->nodesize) {
375 		struct extent_buffer *eb;
376 		bool uptodate;
377 
378 		eb = find_extent_buffer(fs_info, cur);
379 		uptodate = btrfs_subpage_test_uptodate(fs_info, page, cur,
380 						       fs_info->nodesize);
381 
382 		/* A dirty eb shouldn't disappear from buffer_radix */
383 		if (WARN_ON(!eb))
384 			return -EUCLEAN;
385 
386 		if (WARN_ON(cur != btrfs_header_bytenr(eb))) {
387 			free_extent_buffer(eb);
388 			return -EUCLEAN;
389 		}
390 		if (WARN_ON(!uptodate)) {
391 			free_extent_buffer(eb);
392 			return -EUCLEAN;
393 		}
394 
395 		ret = csum_one_extent_buffer(eb);
396 		free_extent_buffer(eb);
397 		if (ret < 0)
398 			return ret;
399 	}
400 	return ret;
401 }
402 
403 /*
404  * Checksum a dirty tree block before IO.  This has extra checks to make sure
405  * we only fill in the checksum field in the first page of a multi-page block.
406  * For subpage extent buffers we need bvec to also read the offset in the page.
407  */
408 static int csum_dirty_buffer(struct btrfs_fs_info *fs_info, struct bio_vec *bvec)
409 {
410 	struct page *page = bvec->bv_page;
411 	u64 start = page_offset(page);
412 	u64 found_start;
413 	struct extent_buffer *eb;
414 
415 	if (fs_info->nodesize < PAGE_SIZE)
416 		return csum_dirty_subpage_buffers(fs_info, bvec);
417 
418 	eb = (struct extent_buffer *)page->private;
419 	if (page != eb->pages[0])
420 		return 0;
421 
422 	found_start = btrfs_header_bytenr(eb);
423 
424 	if (test_bit(EXTENT_BUFFER_NO_CHECK, &eb->bflags)) {
425 		WARN_ON(found_start != 0);
426 		return 0;
427 	}
428 
429 	/*
430 	 * Please do not consolidate these warnings into a single if.
431 	 * It is useful to know what went wrong.
432 	 */
433 	if (WARN_ON(found_start != start))
434 		return -EUCLEAN;
435 	if (WARN_ON(!PageUptodate(page)))
436 		return -EUCLEAN;
437 
438 	return csum_one_extent_buffer(eb);
439 }
440 
441 blk_status_t btree_csum_one_bio(struct btrfs_bio *bbio)
442 {
443 	struct btrfs_fs_info *fs_info = bbio->inode->root->fs_info;
444 	struct bvec_iter iter;
445 	struct bio_vec bv;
446 	int ret = 0;
447 
448 	bio_for_each_segment(bv, &bbio->bio, iter) {
449 		ret = csum_dirty_buffer(fs_info, &bv);
450 		if (ret)
451 			break;
452 	}
453 
454 	return errno_to_blk_status(ret);
455 }
456 
457 static int check_tree_block_fsid(struct extent_buffer *eb)
458 {
459 	struct btrfs_fs_info *fs_info = eb->fs_info;
460 	struct btrfs_fs_devices *fs_devices = fs_info->fs_devices, *seed_devs;
461 	u8 fsid[BTRFS_FSID_SIZE];
462 	u8 *metadata_uuid;
463 
464 	read_extent_buffer(eb, fsid, offsetof(struct btrfs_header, fsid),
465 			   BTRFS_FSID_SIZE);
466 	/*
467 	 * Checking the incompat flag is only valid for the current fs. For
468 	 * seed devices it's forbidden to have their uuid changed so reading
469 	 * ->fsid in this case is fine
470 	 */
471 	if (btrfs_fs_incompat(fs_info, METADATA_UUID))
472 		metadata_uuid = fs_devices->metadata_uuid;
473 	else
474 		metadata_uuid = fs_devices->fsid;
475 
476 	if (!memcmp(fsid, metadata_uuid, BTRFS_FSID_SIZE))
477 		return 0;
478 
479 	list_for_each_entry(seed_devs, &fs_devices->seed_list, seed_list)
480 		if (!memcmp(fsid, seed_devs->fsid, BTRFS_FSID_SIZE))
481 			return 0;
482 
483 	return 1;
484 }
485 
486 /* Do basic extent buffer checks at read time */
487 static int validate_extent_buffer(struct extent_buffer *eb,
488 				  struct btrfs_tree_parent_check *check)
489 {
490 	struct btrfs_fs_info *fs_info = eb->fs_info;
491 	u64 found_start;
492 	const u32 csum_size = fs_info->csum_size;
493 	u8 found_level;
494 	u8 result[BTRFS_CSUM_SIZE];
495 	const u8 *header_csum;
496 	int ret = 0;
497 
498 	ASSERT(check);
499 
500 	found_start = btrfs_header_bytenr(eb);
501 	if (found_start != eb->start) {
502 		btrfs_err_rl(fs_info,
503 			"bad tree block start, mirror %u want %llu have %llu",
504 			     eb->read_mirror, eb->start, found_start);
505 		ret = -EIO;
506 		goto out;
507 	}
508 	if (check_tree_block_fsid(eb)) {
509 		btrfs_err_rl(fs_info, "bad fsid on logical %llu mirror %u",
510 			     eb->start, eb->read_mirror);
511 		ret = -EIO;
512 		goto out;
513 	}
514 	found_level = btrfs_header_level(eb);
515 	if (found_level >= BTRFS_MAX_LEVEL) {
516 		btrfs_err(fs_info,
517 			"bad tree block level, mirror %u level %d on logical %llu",
518 			eb->read_mirror, btrfs_header_level(eb), eb->start);
519 		ret = -EIO;
520 		goto out;
521 	}
522 
523 	csum_tree_block(eb, result);
524 	header_csum = page_address(eb->pages[0]) +
525 		get_eb_offset_in_page(eb, offsetof(struct btrfs_header, csum));
526 
527 	if (memcmp(result, header_csum, csum_size) != 0) {
528 		btrfs_warn_rl(fs_info,
529 "checksum verify failed on logical %llu mirror %u wanted " CSUM_FMT " found " CSUM_FMT " level %d",
530 			      eb->start, eb->read_mirror,
531 			      CSUM_FMT_VALUE(csum_size, header_csum),
532 			      CSUM_FMT_VALUE(csum_size, result),
533 			      btrfs_header_level(eb));
534 		ret = -EUCLEAN;
535 		goto out;
536 	}
537 
538 	if (found_level != check->level) {
539 		btrfs_err(fs_info,
540 		"level verify failed on logical %llu mirror %u wanted %u found %u",
541 			  eb->start, eb->read_mirror, check->level, found_level);
542 		ret = -EIO;
543 		goto out;
544 	}
545 	if (unlikely(check->transid &&
546 		     btrfs_header_generation(eb) != check->transid)) {
547 		btrfs_err_rl(eb->fs_info,
548 "parent transid verify failed on logical %llu mirror %u wanted %llu found %llu",
549 				eb->start, eb->read_mirror, check->transid,
550 				btrfs_header_generation(eb));
551 		ret = -EIO;
552 		goto out;
553 	}
554 	if (check->has_first_key) {
555 		struct btrfs_key *expect_key = &check->first_key;
556 		struct btrfs_key found_key;
557 
558 		if (found_level)
559 			btrfs_node_key_to_cpu(eb, &found_key, 0);
560 		else
561 			btrfs_item_key_to_cpu(eb, &found_key, 0);
562 		if (unlikely(btrfs_comp_cpu_keys(expect_key, &found_key))) {
563 			btrfs_err(fs_info,
564 "tree first key mismatch detected, bytenr=%llu parent_transid=%llu key expected=(%llu,%u,%llu) has=(%llu,%u,%llu)",
565 				  eb->start, check->transid,
566 				  expect_key->objectid,
567 				  expect_key->type, expect_key->offset,
568 				  found_key.objectid, found_key.type,
569 				  found_key.offset);
570 			ret = -EUCLEAN;
571 			goto out;
572 		}
573 	}
574 	if (check->owner_root) {
575 		ret = btrfs_check_eb_owner(eb, check->owner_root);
576 		if (ret < 0)
577 			goto out;
578 	}
579 
580 	/*
581 	 * If this is a leaf block and it is corrupt, set the corrupt bit so
582 	 * that we don't try and read the other copies of this block, just
583 	 * return -EIO.
584 	 */
585 	if (found_level == 0 && btrfs_check_leaf_full(eb)) {
586 		set_bit(EXTENT_BUFFER_CORRUPT, &eb->bflags);
587 		ret = -EIO;
588 	}
589 
590 	if (found_level > 0 && btrfs_check_node(eb))
591 		ret = -EIO;
592 
593 	if (!ret)
594 		set_extent_buffer_uptodate(eb);
595 	else
596 		btrfs_err(fs_info,
597 		"read time tree block corruption detected on logical %llu mirror %u",
598 			  eb->start, eb->read_mirror);
599 out:
600 	return ret;
601 }
602 
603 static int validate_subpage_buffer(struct page *page, u64 start, u64 end,
604 				   int mirror, struct btrfs_tree_parent_check *check)
605 {
606 	struct btrfs_fs_info *fs_info = btrfs_sb(page->mapping->host->i_sb);
607 	struct extent_buffer *eb;
608 	bool reads_done;
609 	int ret = 0;
610 
611 	ASSERT(check);
612 
613 	/*
614 	 * We don't allow bio merge for subpage metadata read, so we should
615 	 * only get one eb for each endio hook.
616 	 */
617 	ASSERT(end == start + fs_info->nodesize - 1);
618 	ASSERT(PagePrivate(page));
619 
620 	eb = find_extent_buffer(fs_info, start);
621 	/*
622 	 * When we are reading one tree block, eb must have been inserted into
623 	 * the radix tree. If not, something is wrong.
624 	 */
625 	ASSERT(eb);
626 
627 	reads_done = atomic_dec_and_test(&eb->io_pages);
628 	/* Subpage read must finish in page read */
629 	ASSERT(reads_done);
630 
631 	eb->read_mirror = mirror;
632 	if (test_bit(EXTENT_BUFFER_READ_ERR, &eb->bflags)) {
633 		ret = -EIO;
634 		goto err;
635 	}
636 	ret = validate_extent_buffer(eb, check);
637 	if (ret < 0)
638 		goto err;
639 
640 	set_extent_buffer_uptodate(eb);
641 
642 	free_extent_buffer(eb);
643 	return ret;
644 err:
645 	/*
646 	 * end_bio_extent_readpage decrements io_pages in case of error,
647 	 * make sure it has something to decrement.
648 	 */
649 	atomic_inc(&eb->io_pages);
650 	clear_extent_buffer_uptodate(eb);
651 	free_extent_buffer(eb);
652 	return ret;
653 }
654 
655 int btrfs_validate_metadata_buffer(struct btrfs_bio *bbio,
656 				   struct page *page, u64 start, u64 end,
657 				   int mirror)
658 {
659 	struct extent_buffer *eb;
660 	int ret = 0;
661 	int reads_done;
662 
663 	ASSERT(page->private);
664 
665 	if (btrfs_sb(page->mapping->host->i_sb)->nodesize < PAGE_SIZE)
666 		return validate_subpage_buffer(page, start, end, mirror,
667 					       &bbio->parent_check);
668 
669 	eb = (struct extent_buffer *)page->private;
670 
671 	/*
672 	 * The pending IO might have been the only thing that kept this buffer
673 	 * in memory.  Make sure we have a ref for all this other checks
674 	 */
675 	atomic_inc(&eb->refs);
676 
677 	reads_done = atomic_dec_and_test(&eb->io_pages);
678 	if (!reads_done)
679 		goto err;
680 
681 	eb->read_mirror = mirror;
682 	if (test_bit(EXTENT_BUFFER_READ_ERR, &eb->bflags)) {
683 		ret = -EIO;
684 		goto err;
685 	}
686 	ret = validate_extent_buffer(eb, &bbio->parent_check);
687 err:
688 	if (ret) {
689 		/*
690 		 * our io error hook is going to dec the io pages
691 		 * again, we have to make sure it has something
692 		 * to decrement
693 		 */
694 		atomic_inc(&eb->io_pages);
695 		clear_extent_buffer_uptodate(eb);
696 	}
697 	free_extent_buffer(eb);
698 
699 	return ret;
700 }
701 
702 #ifdef CONFIG_MIGRATION
703 static int btree_migrate_folio(struct address_space *mapping,
704 		struct folio *dst, struct folio *src, enum migrate_mode mode)
705 {
706 	/*
707 	 * we can't safely write a btree page from here,
708 	 * we haven't done the locking hook
709 	 */
710 	if (folio_test_dirty(src))
711 		return -EAGAIN;
712 	/*
713 	 * Buffers may be managed in a filesystem specific way.
714 	 * We must have no buffers or drop them.
715 	 */
716 	if (folio_get_private(src) &&
717 	    !filemap_release_folio(src, GFP_KERNEL))
718 		return -EAGAIN;
719 	return migrate_folio(mapping, dst, src, mode);
720 }
721 #else
722 #define btree_migrate_folio NULL
723 #endif
724 
725 static int btree_writepages(struct address_space *mapping,
726 			    struct writeback_control *wbc)
727 {
728 	struct btrfs_fs_info *fs_info;
729 	int ret;
730 
731 	if (wbc->sync_mode == WB_SYNC_NONE) {
732 
733 		if (wbc->for_kupdate)
734 			return 0;
735 
736 		fs_info = BTRFS_I(mapping->host)->root->fs_info;
737 		/* this is a bit racy, but that's ok */
738 		ret = __percpu_counter_compare(&fs_info->dirty_metadata_bytes,
739 					     BTRFS_DIRTY_METADATA_THRESH,
740 					     fs_info->dirty_metadata_batch);
741 		if (ret < 0)
742 			return 0;
743 	}
744 	return btree_write_cache_pages(mapping, wbc);
745 }
746 
747 static bool btree_release_folio(struct folio *folio, gfp_t gfp_flags)
748 {
749 	if (folio_test_writeback(folio) || folio_test_dirty(folio))
750 		return false;
751 
752 	return try_release_extent_buffer(&folio->page);
753 }
754 
755 static void btree_invalidate_folio(struct folio *folio, size_t offset,
756 				 size_t length)
757 {
758 	struct extent_io_tree *tree;
759 	tree = &BTRFS_I(folio->mapping->host)->io_tree;
760 	extent_invalidate_folio(tree, folio, offset);
761 	btree_release_folio(folio, GFP_NOFS);
762 	if (folio_get_private(folio)) {
763 		btrfs_warn(BTRFS_I(folio->mapping->host)->root->fs_info,
764 			   "folio private not zero on folio %llu",
765 			   (unsigned long long)folio_pos(folio));
766 		folio_detach_private(folio);
767 	}
768 }
769 
770 #ifdef DEBUG
771 static bool btree_dirty_folio(struct address_space *mapping,
772 		struct folio *folio)
773 {
774 	struct btrfs_fs_info *fs_info = btrfs_sb(mapping->host->i_sb);
775 	struct btrfs_subpage *subpage;
776 	struct extent_buffer *eb;
777 	int cur_bit = 0;
778 	u64 page_start = folio_pos(folio);
779 
780 	if (fs_info->sectorsize == PAGE_SIZE) {
781 		eb = folio_get_private(folio);
782 		BUG_ON(!eb);
783 		BUG_ON(!test_bit(EXTENT_BUFFER_DIRTY, &eb->bflags));
784 		BUG_ON(!atomic_read(&eb->refs));
785 		btrfs_assert_tree_write_locked(eb);
786 		return filemap_dirty_folio(mapping, folio);
787 	}
788 	subpage = folio_get_private(folio);
789 
790 	ASSERT(subpage->dirty_bitmap);
791 	while (cur_bit < BTRFS_SUBPAGE_BITMAP_SIZE) {
792 		unsigned long flags;
793 		u64 cur;
794 		u16 tmp = (1 << cur_bit);
795 
796 		spin_lock_irqsave(&subpage->lock, flags);
797 		if (!(tmp & subpage->dirty_bitmap)) {
798 			spin_unlock_irqrestore(&subpage->lock, flags);
799 			cur_bit++;
800 			continue;
801 		}
802 		spin_unlock_irqrestore(&subpage->lock, flags);
803 		cur = page_start + cur_bit * fs_info->sectorsize;
804 
805 		eb = find_extent_buffer(fs_info, cur);
806 		ASSERT(eb);
807 		ASSERT(test_bit(EXTENT_BUFFER_DIRTY, &eb->bflags));
808 		ASSERT(atomic_read(&eb->refs));
809 		btrfs_assert_tree_write_locked(eb);
810 		free_extent_buffer(eb);
811 
812 		cur_bit += (fs_info->nodesize >> fs_info->sectorsize_bits);
813 	}
814 	return filemap_dirty_folio(mapping, folio);
815 }
816 #else
817 #define btree_dirty_folio filemap_dirty_folio
818 #endif
819 
820 static const struct address_space_operations btree_aops = {
821 	.writepages	= btree_writepages,
822 	.release_folio	= btree_release_folio,
823 	.invalidate_folio = btree_invalidate_folio,
824 	.migrate_folio	= btree_migrate_folio,
825 	.dirty_folio	= btree_dirty_folio,
826 };
827 
828 struct extent_buffer *btrfs_find_create_tree_block(
829 						struct btrfs_fs_info *fs_info,
830 						u64 bytenr, u64 owner_root,
831 						int level)
832 {
833 	if (btrfs_is_testing(fs_info))
834 		return alloc_test_extent_buffer(fs_info, bytenr);
835 	return alloc_extent_buffer(fs_info, bytenr, owner_root, level);
836 }
837 
838 /*
839  * Read tree block at logical address @bytenr and do variant basic but critical
840  * verification.
841  *
842  * @check:		expected tree parentness check, see comments of the
843  *			structure for details.
844  */
845 struct extent_buffer *read_tree_block(struct btrfs_fs_info *fs_info, u64 bytenr,
846 				      struct btrfs_tree_parent_check *check)
847 {
848 	struct extent_buffer *buf = NULL;
849 	int ret;
850 
851 	ASSERT(check);
852 
853 	buf = btrfs_find_create_tree_block(fs_info, bytenr, check->owner_root,
854 					   check->level);
855 	if (IS_ERR(buf))
856 		return buf;
857 
858 	ret = btrfs_read_extent_buffer(buf, check);
859 	if (ret) {
860 		free_extent_buffer_stale(buf);
861 		return ERR_PTR(ret);
862 	}
863 	if (btrfs_check_eb_owner(buf, check->owner_root)) {
864 		free_extent_buffer_stale(buf);
865 		return ERR_PTR(-EUCLEAN);
866 	}
867 	return buf;
868 
869 }
870 
871 static void __setup_root(struct btrfs_root *root, struct btrfs_fs_info *fs_info,
872 			 u64 objectid)
873 {
874 	bool dummy = test_bit(BTRFS_FS_STATE_DUMMY_FS_INFO, &fs_info->fs_state);
875 
876 	memset(&root->root_key, 0, sizeof(root->root_key));
877 	memset(&root->root_item, 0, sizeof(root->root_item));
878 	memset(&root->defrag_progress, 0, sizeof(root->defrag_progress));
879 	root->fs_info = fs_info;
880 	root->root_key.objectid = objectid;
881 	root->node = NULL;
882 	root->commit_root = NULL;
883 	root->state = 0;
884 	RB_CLEAR_NODE(&root->rb_node);
885 
886 	root->last_trans = 0;
887 	root->free_objectid = 0;
888 	root->nr_delalloc_inodes = 0;
889 	root->nr_ordered_extents = 0;
890 	root->inode_tree = RB_ROOT;
891 	INIT_RADIX_TREE(&root->delayed_nodes_tree, GFP_ATOMIC);
892 
893 	btrfs_init_root_block_rsv(root);
894 
895 	INIT_LIST_HEAD(&root->dirty_list);
896 	INIT_LIST_HEAD(&root->root_list);
897 	INIT_LIST_HEAD(&root->delalloc_inodes);
898 	INIT_LIST_HEAD(&root->delalloc_root);
899 	INIT_LIST_HEAD(&root->ordered_extents);
900 	INIT_LIST_HEAD(&root->ordered_root);
901 	INIT_LIST_HEAD(&root->reloc_dirty_list);
902 	INIT_LIST_HEAD(&root->logged_list[0]);
903 	INIT_LIST_HEAD(&root->logged_list[1]);
904 	spin_lock_init(&root->inode_lock);
905 	spin_lock_init(&root->delalloc_lock);
906 	spin_lock_init(&root->ordered_extent_lock);
907 	spin_lock_init(&root->accounting_lock);
908 	spin_lock_init(&root->log_extents_lock[0]);
909 	spin_lock_init(&root->log_extents_lock[1]);
910 	spin_lock_init(&root->qgroup_meta_rsv_lock);
911 	mutex_init(&root->objectid_mutex);
912 	mutex_init(&root->log_mutex);
913 	mutex_init(&root->ordered_extent_mutex);
914 	mutex_init(&root->delalloc_mutex);
915 	init_waitqueue_head(&root->qgroup_flush_wait);
916 	init_waitqueue_head(&root->log_writer_wait);
917 	init_waitqueue_head(&root->log_commit_wait[0]);
918 	init_waitqueue_head(&root->log_commit_wait[1]);
919 	INIT_LIST_HEAD(&root->log_ctxs[0]);
920 	INIT_LIST_HEAD(&root->log_ctxs[1]);
921 	atomic_set(&root->log_commit[0], 0);
922 	atomic_set(&root->log_commit[1], 0);
923 	atomic_set(&root->log_writers, 0);
924 	atomic_set(&root->log_batch, 0);
925 	refcount_set(&root->refs, 1);
926 	atomic_set(&root->snapshot_force_cow, 0);
927 	atomic_set(&root->nr_swapfiles, 0);
928 	root->log_transid = 0;
929 	root->log_transid_committed = -1;
930 	root->last_log_commit = 0;
931 	root->anon_dev = 0;
932 	if (!dummy) {
933 		extent_io_tree_init(fs_info, &root->dirty_log_pages,
934 				    IO_TREE_ROOT_DIRTY_LOG_PAGES);
935 		extent_io_tree_init(fs_info, &root->log_csum_range,
936 				    IO_TREE_LOG_CSUM_RANGE);
937 	}
938 
939 	spin_lock_init(&root->root_item_lock);
940 	btrfs_qgroup_init_swapped_blocks(&root->swapped_blocks);
941 #ifdef CONFIG_BTRFS_DEBUG
942 	INIT_LIST_HEAD(&root->leak_list);
943 	spin_lock(&fs_info->fs_roots_radix_lock);
944 	list_add_tail(&root->leak_list, &fs_info->allocated_roots);
945 	spin_unlock(&fs_info->fs_roots_radix_lock);
946 #endif
947 }
948 
949 static struct btrfs_root *btrfs_alloc_root(struct btrfs_fs_info *fs_info,
950 					   u64 objectid, gfp_t flags)
951 {
952 	struct btrfs_root *root = kzalloc(sizeof(*root), flags);
953 	if (root)
954 		__setup_root(root, fs_info, objectid);
955 	return root;
956 }
957 
958 #ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
959 /* Should only be used by the testing infrastructure */
960 struct btrfs_root *btrfs_alloc_dummy_root(struct btrfs_fs_info *fs_info)
961 {
962 	struct btrfs_root *root;
963 
964 	if (!fs_info)
965 		return ERR_PTR(-EINVAL);
966 
967 	root = btrfs_alloc_root(fs_info, BTRFS_ROOT_TREE_OBJECTID, GFP_KERNEL);
968 	if (!root)
969 		return ERR_PTR(-ENOMEM);
970 
971 	/* We don't use the stripesize in selftest, set it as sectorsize */
972 	root->alloc_bytenr = 0;
973 
974 	return root;
975 }
976 #endif
977 
978 static int global_root_cmp(struct rb_node *a_node, const struct rb_node *b_node)
979 {
980 	const struct btrfs_root *a = rb_entry(a_node, struct btrfs_root, rb_node);
981 	const struct btrfs_root *b = rb_entry(b_node, struct btrfs_root, rb_node);
982 
983 	return btrfs_comp_cpu_keys(&a->root_key, &b->root_key);
984 }
985 
986 static int global_root_key_cmp(const void *k, const struct rb_node *node)
987 {
988 	const struct btrfs_key *key = k;
989 	const struct btrfs_root *root = rb_entry(node, struct btrfs_root, rb_node);
990 
991 	return btrfs_comp_cpu_keys(key, &root->root_key);
992 }
993 
994 int btrfs_global_root_insert(struct btrfs_root *root)
995 {
996 	struct btrfs_fs_info *fs_info = root->fs_info;
997 	struct rb_node *tmp;
998 
999 	write_lock(&fs_info->global_root_lock);
1000 	tmp = rb_find_add(&root->rb_node, &fs_info->global_root_tree, global_root_cmp);
1001 	write_unlock(&fs_info->global_root_lock);
1002 	ASSERT(!tmp);
1003 
1004 	return tmp ? -EEXIST : 0;
1005 }
1006 
1007 void btrfs_global_root_delete(struct btrfs_root *root)
1008 {
1009 	struct btrfs_fs_info *fs_info = root->fs_info;
1010 
1011 	write_lock(&fs_info->global_root_lock);
1012 	rb_erase(&root->rb_node, &fs_info->global_root_tree);
1013 	write_unlock(&fs_info->global_root_lock);
1014 }
1015 
1016 struct btrfs_root *btrfs_global_root(struct btrfs_fs_info *fs_info,
1017 				     struct btrfs_key *key)
1018 {
1019 	struct rb_node *node;
1020 	struct btrfs_root *root = NULL;
1021 
1022 	read_lock(&fs_info->global_root_lock);
1023 	node = rb_find(key, &fs_info->global_root_tree, global_root_key_cmp);
1024 	if (node)
1025 		root = container_of(node, struct btrfs_root, rb_node);
1026 	read_unlock(&fs_info->global_root_lock);
1027 
1028 	return root;
1029 }
1030 
1031 static u64 btrfs_global_root_id(struct btrfs_fs_info *fs_info, u64 bytenr)
1032 {
1033 	struct btrfs_block_group *block_group;
1034 	u64 ret;
1035 
1036 	if (!btrfs_fs_incompat(fs_info, EXTENT_TREE_V2))
1037 		return 0;
1038 
1039 	if (bytenr)
1040 		block_group = btrfs_lookup_block_group(fs_info, bytenr);
1041 	else
1042 		block_group = btrfs_lookup_first_block_group(fs_info, bytenr);
1043 	ASSERT(block_group);
1044 	if (!block_group)
1045 		return 0;
1046 	ret = block_group->global_root_id;
1047 	btrfs_put_block_group(block_group);
1048 
1049 	return ret;
1050 }
1051 
1052 struct btrfs_root *btrfs_csum_root(struct btrfs_fs_info *fs_info, u64 bytenr)
1053 {
1054 	struct btrfs_key key = {
1055 		.objectid = BTRFS_CSUM_TREE_OBJECTID,
1056 		.type = BTRFS_ROOT_ITEM_KEY,
1057 		.offset = btrfs_global_root_id(fs_info, bytenr),
1058 	};
1059 
1060 	return btrfs_global_root(fs_info, &key);
1061 }
1062 
1063 struct btrfs_root *btrfs_extent_root(struct btrfs_fs_info *fs_info, u64 bytenr)
1064 {
1065 	struct btrfs_key key = {
1066 		.objectid = BTRFS_EXTENT_TREE_OBJECTID,
1067 		.type = BTRFS_ROOT_ITEM_KEY,
1068 		.offset = btrfs_global_root_id(fs_info, bytenr),
1069 	};
1070 
1071 	return btrfs_global_root(fs_info, &key);
1072 }
1073 
1074 struct btrfs_root *btrfs_block_group_root(struct btrfs_fs_info *fs_info)
1075 {
1076 	if (btrfs_fs_compat_ro(fs_info, BLOCK_GROUP_TREE))
1077 		return fs_info->block_group_root;
1078 	return btrfs_extent_root(fs_info, 0);
1079 }
1080 
1081 struct btrfs_root *btrfs_create_tree(struct btrfs_trans_handle *trans,
1082 				     u64 objectid)
1083 {
1084 	struct btrfs_fs_info *fs_info = trans->fs_info;
1085 	struct extent_buffer *leaf;
1086 	struct btrfs_root *tree_root = fs_info->tree_root;
1087 	struct btrfs_root *root;
1088 	struct btrfs_key key;
1089 	unsigned int nofs_flag;
1090 	int ret = 0;
1091 
1092 	/*
1093 	 * We're holding a transaction handle, so use a NOFS memory allocation
1094 	 * context to avoid deadlock if reclaim happens.
1095 	 */
1096 	nofs_flag = memalloc_nofs_save();
1097 	root = btrfs_alloc_root(fs_info, objectid, GFP_KERNEL);
1098 	memalloc_nofs_restore(nofs_flag);
1099 	if (!root)
1100 		return ERR_PTR(-ENOMEM);
1101 
1102 	root->root_key.objectid = objectid;
1103 	root->root_key.type = BTRFS_ROOT_ITEM_KEY;
1104 	root->root_key.offset = 0;
1105 
1106 	leaf = btrfs_alloc_tree_block(trans, root, 0, objectid, NULL, 0, 0, 0,
1107 				      BTRFS_NESTING_NORMAL);
1108 	if (IS_ERR(leaf)) {
1109 		ret = PTR_ERR(leaf);
1110 		leaf = NULL;
1111 		goto fail;
1112 	}
1113 
1114 	root->node = leaf;
1115 	btrfs_mark_buffer_dirty(leaf);
1116 
1117 	root->commit_root = btrfs_root_node(root);
1118 	set_bit(BTRFS_ROOT_TRACK_DIRTY, &root->state);
1119 
1120 	btrfs_set_root_flags(&root->root_item, 0);
1121 	btrfs_set_root_limit(&root->root_item, 0);
1122 	btrfs_set_root_bytenr(&root->root_item, leaf->start);
1123 	btrfs_set_root_generation(&root->root_item, trans->transid);
1124 	btrfs_set_root_level(&root->root_item, 0);
1125 	btrfs_set_root_refs(&root->root_item, 1);
1126 	btrfs_set_root_used(&root->root_item, leaf->len);
1127 	btrfs_set_root_last_snapshot(&root->root_item, 0);
1128 	btrfs_set_root_dirid(&root->root_item, 0);
1129 	if (is_fstree(objectid))
1130 		generate_random_guid(root->root_item.uuid);
1131 	else
1132 		export_guid(root->root_item.uuid, &guid_null);
1133 	btrfs_set_root_drop_level(&root->root_item, 0);
1134 
1135 	btrfs_tree_unlock(leaf);
1136 
1137 	key.objectid = objectid;
1138 	key.type = BTRFS_ROOT_ITEM_KEY;
1139 	key.offset = 0;
1140 	ret = btrfs_insert_root(trans, tree_root, &key, &root->root_item);
1141 	if (ret)
1142 		goto fail;
1143 
1144 	return root;
1145 
1146 fail:
1147 	btrfs_put_root(root);
1148 
1149 	return ERR_PTR(ret);
1150 }
1151 
1152 static struct btrfs_root *alloc_log_tree(struct btrfs_trans_handle *trans,
1153 					 struct btrfs_fs_info *fs_info)
1154 {
1155 	struct btrfs_root *root;
1156 
1157 	root = btrfs_alloc_root(fs_info, BTRFS_TREE_LOG_OBJECTID, GFP_NOFS);
1158 	if (!root)
1159 		return ERR_PTR(-ENOMEM);
1160 
1161 	root->root_key.objectid = BTRFS_TREE_LOG_OBJECTID;
1162 	root->root_key.type = BTRFS_ROOT_ITEM_KEY;
1163 	root->root_key.offset = BTRFS_TREE_LOG_OBJECTID;
1164 
1165 	return root;
1166 }
1167 
1168 int btrfs_alloc_log_tree_node(struct btrfs_trans_handle *trans,
1169 			      struct btrfs_root *root)
1170 {
1171 	struct extent_buffer *leaf;
1172 
1173 	/*
1174 	 * DON'T set SHAREABLE bit for log trees.
1175 	 *
1176 	 * Log trees are not exposed to user space thus can't be snapshotted,
1177 	 * and they go away before a real commit is actually done.
1178 	 *
1179 	 * They do store pointers to file data extents, and those reference
1180 	 * counts still get updated (along with back refs to the log tree).
1181 	 */
1182 
1183 	leaf = btrfs_alloc_tree_block(trans, root, 0, BTRFS_TREE_LOG_OBJECTID,
1184 			NULL, 0, 0, 0, BTRFS_NESTING_NORMAL);
1185 	if (IS_ERR(leaf))
1186 		return PTR_ERR(leaf);
1187 
1188 	root->node = leaf;
1189 
1190 	btrfs_mark_buffer_dirty(root->node);
1191 	btrfs_tree_unlock(root->node);
1192 
1193 	return 0;
1194 }
1195 
1196 int btrfs_init_log_root_tree(struct btrfs_trans_handle *trans,
1197 			     struct btrfs_fs_info *fs_info)
1198 {
1199 	struct btrfs_root *log_root;
1200 
1201 	log_root = alloc_log_tree(trans, fs_info);
1202 	if (IS_ERR(log_root))
1203 		return PTR_ERR(log_root);
1204 
1205 	if (!btrfs_is_zoned(fs_info)) {
1206 		int ret = btrfs_alloc_log_tree_node(trans, log_root);
1207 
1208 		if (ret) {
1209 			btrfs_put_root(log_root);
1210 			return ret;
1211 		}
1212 	}
1213 
1214 	WARN_ON(fs_info->log_root_tree);
1215 	fs_info->log_root_tree = log_root;
1216 	return 0;
1217 }
1218 
1219 int btrfs_add_log_tree(struct btrfs_trans_handle *trans,
1220 		       struct btrfs_root *root)
1221 {
1222 	struct btrfs_fs_info *fs_info = root->fs_info;
1223 	struct btrfs_root *log_root;
1224 	struct btrfs_inode_item *inode_item;
1225 	int ret;
1226 
1227 	log_root = alloc_log_tree(trans, fs_info);
1228 	if (IS_ERR(log_root))
1229 		return PTR_ERR(log_root);
1230 
1231 	ret = btrfs_alloc_log_tree_node(trans, log_root);
1232 	if (ret) {
1233 		btrfs_put_root(log_root);
1234 		return ret;
1235 	}
1236 
1237 	log_root->last_trans = trans->transid;
1238 	log_root->root_key.offset = root->root_key.objectid;
1239 
1240 	inode_item = &log_root->root_item.inode;
1241 	btrfs_set_stack_inode_generation(inode_item, 1);
1242 	btrfs_set_stack_inode_size(inode_item, 3);
1243 	btrfs_set_stack_inode_nlink(inode_item, 1);
1244 	btrfs_set_stack_inode_nbytes(inode_item,
1245 				     fs_info->nodesize);
1246 	btrfs_set_stack_inode_mode(inode_item, S_IFDIR | 0755);
1247 
1248 	btrfs_set_root_node(&log_root->root_item, log_root->node);
1249 
1250 	WARN_ON(root->log_root);
1251 	root->log_root = log_root;
1252 	root->log_transid = 0;
1253 	root->log_transid_committed = -1;
1254 	root->last_log_commit = 0;
1255 	return 0;
1256 }
1257 
1258 static struct btrfs_root *read_tree_root_path(struct btrfs_root *tree_root,
1259 					      struct btrfs_path *path,
1260 					      struct btrfs_key *key)
1261 {
1262 	struct btrfs_root *root;
1263 	struct btrfs_tree_parent_check check = { 0 };
1264 	struct btrfs_fs_info *fs_info = tree_root->fs_info;
1265 	u64 generation;
1266 	int ret;
1267 	int level;
1268 
1269 	root = btrfs_alloc_root(fs_info, key->objectid, GFP_NOFS);
1270 	if (!root)
1271 		return ERR_PTR(-ENOMEM);
1272 
1273 	ret = btrfs_find_root(tree_root, key, path,
1274 			      &root->root_item, &root->root_key);
1275 	if (ret) {
1276 		if (ret > 0)
1277 			ret = -ENOENT;
1278 		goto fail;
1279 	}
1280 
1281 	generation = btrfs_root_generation(&root->root_item);
1282 	level = btrfs_root_level(&root->root_item);
1283 	check.level = level;
1284 	check.transid = generation;
1285 	check.owner_root = key->objectid;
1286 	root->node = read_tree_block(fs_info, btrfs_root_bytenr(&root->root_item),
1287 				     &check);
1288 	if (IS_ERR(root->node)) {
1289 		ret = PTR_ERR(root->node);
1290 		root->node = NULL;
1291 		goto fail;
1292 	}
1293 	if (!btrfs_buffer_uptodate(root->node, generation, 0)) {
1294 		ret = -EIO;
1295 		goto fail;
1296 	}
1297 
1298 	/*
1299 	 * For real fs, and not log/reloc trees, root owner must
1300 	 * match its root node owner
1301 	 */
1302 	if (!test_bit(BTRFS_FS_STATE_DUMMY_FS_INFO, &fs_info->fs_state) &&
1303 	    root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID &&
1304 	    root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID &&
1305 	    root->root_key.objectid != btrfs_header_owner(root->node)) {
1306 		btrfs_crit(fs_info,
1307 "root=%llu block=%llu, tree root owner mismatch, have %llu expect %llu",
1308 			   root->root_key.objectid, root->node->start,
1309 			   btrfs_header_owner(root->node),
1310 			   root->root_key.objectid);
1311 		ret = -EUCLEAN;
1312 		goto fail;
1313 	}
1314 	root->commit_root = btrfs_root_node(root);
1315 	return root;
1316 fail:
1317 	btrfs_put_root(root);
1318 	return ERR_PTR(ret);
1319 }
1320 
1321 struct btrfs_root *btrfs_read_tree_root(struct btrfs_root *tree_root,
1322 					struct btrfs_key *key)
1323 {
1324 	struct btrfs_root *root;
1325 	struct btrfs_path *path;
1326 
1327 	path = btrfs_alloc_path();
1328 	if (!path)
1329 		return ERR_PTR(-ENOMEM);
1330 	root = read_tree_root_path(tree_root, path, key);
1331 	btrfs_free_path(path);
1332 
1333 	return root;
1334 }
1335 
1336 /*
1337  * Initialize subvolume root in-memory structure
1338  *
1339  * @anon_dev:	anonymous device to attach to the root, if zero, allocate new
1340  */
1341 static int btrfs_init_fs_root(struct btrfs_root *root, dev_t anon_dev)
1342 {
1343 	int ret;
1344 	unsigned int nofs_flag;
1345 
1346 	/*
1347 	 * We might be called under a transaction (e.g. indirect backref
1348 	 * resolution) which could deadlock if it triggers memory reclaim
1349 	 */
1350 	nofs_flag = memalloc_nofs_save();
1351 	ret = btrfs_drew_lock_init(&root->snapshot_lock);
1352 	memalloc_nofs_restore(nofs_flag);
1353 	if (ret)
1354 		goto fail;
1355 
1356 	if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID &&
1357 	    !btrfs_is_data_reloc_root(root)) {
1358 		set_bit(BTRFS_ROOT_SHAREABLE, &root->state);
1359 		btrfs_check_and_init_root_item(&root->root_item);
1360 	}
1361 
1362 	/*
1363 	 * Don't assign anonymous block device to roots that are not exposed to
1364 	 * userspace, the id pool is limited to 1M
1365 	 */
1366 	if (is_fstree(root->root_key.objectid) &&
1367 	    btrfs_root_refs(&root->root_item) > 0) {
1368 		if (!anon_dev) {
1369 			ret = get_anon_bdev(&root->anon_dev);
1370 			if (ret)
1371 				goto fail;
1372 		} else {
1373 			root->anon_dev = anon_dev;
1374 		}
1375 	}
1376 
1377 	mutex_lock(&root->objectid_mutex);
1378 	ret = btrfs_init_root_free_objectid(root);
1379 	if (ret) {
1380 		mutex_unlock(&root->objectid_mutex);
1381 		goto fail;
1382 	}
1383 
1384 	ASSERT(root->free_objectid <= BTRFS_LAST_FREE_OBJECTID);
1385 
1386 	mutex_unlock(&root->objectid_mutex);
1387 
1388 	return 0;
1389 fail:
1390 	/* The caller is responsible to call btrfs_free_fs_root */
1391 	return ret;
1392 }
1393 
1394 static struct btrfs_root *btrfs_lookup_fs_root(struct btrfs_fs_info *fs_info,
1395 					       u64 root_id)
1396 {
1397 	struct btrfs_root *root;
1398 
1399 	spin_lock(&fs_info->fs_roots_radix_lock);
1400 	root = radix_tree_lookup(&fs_info->fs_roots_radix,
1401 				 (unsigned long)root_id);
1402 	if (root)
1403 		root = btrfs_grab_root(root);
1404 	spin_unlock(&fs_info->fs_roots_radix_lock);
1405 	return root;
1406 }
1407 
1408 static struct btrfs_root *btrfs_get_global_root(struct btrfs_fs_info *fs_info,
1409 						u64 objectid)
1410 {
1411 	struct btrfs_key key = {
1412 		.objectid = objectid,
1413 		.type = BTRFS_ROOT_ITEM_KEY,
1414 		.offset = 0,
1415 	};
1416 
1417 	if (objectid == BTRFS_ROOT_TREE_OBJECTID)
1418 		return btrfs_grab_root(fs_info->tree_root);
1419 	if (objectid == BTRFS_EXTENT_TREE_OBJECTID)
1420 		return btrfs_grab_root(btrfs_global_root(fs_info, &key));
1421 	if (objectid == BTRFS_CHUNK_TREE_OBJECTID)
1422 		return btrfs_grab_root(fs_info->chunk_root);
1423 	if (objectid == BTRFS_DEV_TREE_OBJECTID)
1424 		return btrfs_grab_root(fs_info->dev_root);
1425 	if (objectid == BTRFS_CSUM_TREE_OBJECTID)
1426 		return btrfs_grab_root(btrfs_global_root(fs_info, &key));
1427 	if (objectid == BTRFS_QUOTA_TREE_OBJECTID)
1428 		return btrfs_grab_root(fs_info->quota_root) ?
1429 			fs_info->quota_root : ERR_PTR(-ENOENT);
1430 	if (objectid == BTRFS_UUID_TREE_OBJECTID)
1431 		return btrfs_grab_root(fs_info->uuid_root) ?
1432 			fs_info->uuid_root : ERR_PTR(-ENOENT);
1433 	if (objectid == BTRFS_BLOCK_GROUP_TREE_OBJECTID)
1434 		return btrfs_grab_root(fs_info->block_group_root) ?
1435 			fs_info->block_group_root : ERR_PTR(-ENOENT);
1436 	if (objectid == BTRFS_FREE_SPACE_TREE_OBJECTID) {
1437 		struct btrfs_root *root = btrfs_global_root(fs_info, &key);
1438 
1439 		return btrfs_grab_root(root) ? root : ERR_PTR(-ENOENT);
1440 	}
1441 	return NULL;
1442 }
1443 
1444 int btrfs_insert_fs_root(struct btrfs_fs_info *fs_info,
1445 			 struct btrfs_root *root)
1446 {
1447 	int ret;
1448 
1449 	ret = radix_tree_preload(GFP_NOFS);
1450 	if (ret)
1451 		return ret;
1452 
1453 	spin_lock(&fs_info->fs_roots_radix_lock);
1454 	ret = radix_tree_insert(&fs_info->fs_roots_radix,
1455 				(unsigned long)root->root_key.objectid,
1456 				root);
1457 	if (ret == 0) {
1458 		btrfs_grab_root(root);
1459 		set_bit(BTRFS_ROOT_IN_RADIX, &root->state);
1460 	}
1461 	spin_unlock(&fs_info->fs_roots_radix_lock);
1462 	radix_tree_preload_end();
1463 
1464 	return ret;
1465 }
1466 
1467 void btrfs_check_leaked_roots(struct btrfs_fs_info *fs_info)
1468 {
1469 #ifdef CONFIG_BTRFS_DEBUG
1470 	struct btrfs_root *root;
1471 
1472 	while (!list_empty(&fs_info->allocated_roots)) {
1473 		char buf[BTRFS_ROOT_NAME_BUF_LEN];
1474 
1475 		root = list_first_entry(&fs_info->allocated_roots,
1476 					struct btrfs_root, leak_list);
1477 		btrfs_err(fs_info, "leaked root %s refcount %d",
1478 			  btrfs_root_name(&root->root_key, buf),
1479 			  refcount_read(&root->refs));
1480 		while (refcount_read(&root->refs) > 1)
1481 			btrfs_put_root(root);
1482 		btrfs_put_root(root);
1483 	}
1484 #endif
1485 }
1486 
1487 static void free_global_roots(struct btrfs_fs_info *fs_info)
1488 {
1489 	struct btrfs_root *root;
1490 	struct rb_node *node;
1491 
1492 	while ((node = rb_first_postorder(&fs_info->global_root_tree)) != NULL) {
1493 		root = rb_entry(node, struct btrfs_root, rb_node);
1494 		rb_erase(&root->rb_node, &fs_info->global_root_tree);
1495 		btrfs_put_root(root);
1496 	}
1497 }
1498 
1499 void btrfs_free_fs_info(struct btrfs_fs_info *fs_info)
1500 {
1501 	percpu_counter_destroy(&fs_info->dirty_metadata_bytes);
1502 	percpu_counter_destroy(&fs_info->delalloc_bytes);
1503 	percpu_counter_destroy(&fs_info->ordered_bytes);
1504 	percpu_counter_destroy(&fs_info->dev_replace.bio_counter);
1505 	btrfs_free_csum_hash(fs_info);
1506 	btrfs_free_stripe_hash_table(fs_info);
1507 	btrfs_free_ref_cache(fs_info);
1508 	kfree(fs_info->balance_ctl);
1509 	kfree(fs_info->delayed_root);
1510 	free_global_roots(fs_info);
1511 	btrfs_put_root(fs_info->tree_root);
1512 	btrfs_put_root(fs_info->chunk_root);
1513 	btrfs_put_root(fs_info->dev_root);
1514 	btrfs_put_root(fs_info->quota_root);
1515 	btrfs_put_root(fs_info->uuid_root);
1516 	btrfs_put_root(fs_info->fs_root);
1517 	btrfs_put_root(fs_info->data_reloc_root);
1518 	btrfs_put_root(fs_info->block_group_root);
1519 	btrfs_check_leaked_roots(fs_info);
1520 	btrfs_extent_buffer_leak_debug_check(fs_info);
1521 	kfree(fs_info->super_copy);
1522 	kfree(fs_info->super_for_commit);
1523 	kfree(fs_info->subpage_info);
1524 	kvfree(fs_info);
1525 }
1526 
1527 
1528 /*
1529  * Get an in-memory reference of a root structure.
1530  *
1531  * For essential trees like root/extent tree, we grab it from fs_info directly.
1532  * For subvolume trees, we check the cached filesystem roots first. If not
1533  * found, then read it from disk and add it to cached fs roots.
1534  *
1535  * Caller should release the root by calling btrfs_put_root() after the usage.
1536  *
1537  * NOTE: Reloc and log trees can't be read by this function as they share the
1538  *	 same root objectid.
1539  *
1540  * @objectid:	root id
1541  * @anon_dev:	preallocated anonymous block device number for new roots,
1542  * 		pass 0 for new allocation.
1543  * @check_ref:	whether to check root item references, If true, return -ENOENT
1544  *		for orphan roots
1545  */
1546 static struct btrfs_root *btrfs_get_root_ref(struct btrfs_fs_info *fs_info,
1547 					     u64 objectid, dev_t anon_dev,
1548 					     bool check_ref)
1549 {
1550 	struct btrfs_root *root;
1551 	struct btrfs_path *path;
1552 	struct btrfs_key key;
1553 	int ret;
1554 
1555 	root = btrfs_get_global_root(fs_info, objectid);
1556 	if (root)
1557 		return root;
1558 again:
1559 	root = btrfs_lookup_fs_root(fs_info, objectid);
1560 	if (root) {
1561 		/* Shouldn't get preallocated anon_dev for cached roots */
1562 		ASSERT(!anon_dev);
1563 		if (check_ref && btrfs_root_refs(&root->root_item) == 0) {
1564 			btrfs_put_root(root);
1565 			return ERR_PTR(-ENOENT);
1566 		}
1567 		return root;
1568 	}
1569 
1570 	key.objectid = objectid;
1571 	key.type = BTRFS_ROOT_ITEM_KEY;
1572 	key.offset = (u64)-1;
1573 	root = btrfs_read_tree_root(fs_info->tree_root, &key);
1574 	if (IS_ERR(root))
1575 		return root;
1576 
1577 	if (check_ref && btrfs_root_refs(&root->root_item) == 0) {
1578 		ret = -ENOENT;
1579 		goto fail;
1580 	}
1581 
1582 	ret = btrfs_init_fs_root(root, anon_dev);
1583 	if (ret)
1584 		goto fail;
1585 
1586 	path = btrfs_alloc_path();
1587 	if (!path) {
1588 		ret = -ENOMEM;
1589 		goto fail;
1590 	}
1591 	key.objectid = BTRFS_ORPHAN_OBJECTID;
1592 	key.type = BTRFS_ORPHAN_ITEM_KEY;
1593 	key.offset = objectid;
1594 
1595 	ret = btrfs_search_slot(NULL, fs_info->tree_root, &key, path, 0, 0);
1596 	btrfs_free_path(path);
1597 	if (ret < 0)
1598 		goto fail;
1599 	if (ret == 0)
1600 		set_bit(BTRFS_ROOT_ORPHAN_ITEM_INSERTED, &root->state);
1601 
1602 	ret = btrfs_insert_fs_root(fs_info, root);
1603 	if (ret) {
1604 		if (ret == -EEXIST) {
1605 			btrfs_put_root(root);
1606 			goto again;
1607 		}
1608 		goto fail;
1609 	}
1610 	return root;
1611 fail:
1612 	/*
1613 	 * If our caller provided us an anonymous device, then it's his
1614 	 * responsibility to free it in case we fail. So we have to set our
1615 	 * root's anon_dev to 0 to avoid a double free, once by btrfs_put_root()
1616 	 * and once again by our caller.
1617 	 */
1618 	if (anon_dev)
1619 		root->anon_dev = 0;
1620 	btrfs_put_root(root);
1621 	return ERR_PTR(ret);
1622 }
1623 
1624 /*
1625  * Get in-memory reference of a root structure
1626  *
1627  * @objectid:	tree objectid
1628  * @check_ref:	if set, verify that the tree exists and the item has at least
1629  *		one reference
1630  */
1631 struct btrfs_root *btrfs_get_fs_root(struct btrfs_fs_info *fs_info,
1632 				     u64 objectid, bool check_ref)
1633 {
1634 	return btrfs_get_root_ref(fs_info, objectid, 0, check_ref);
1635 }
1636 
1637 /*
1638  * Get in-memory reference of a root structure, created as new, optionally pass
1639  * the anonymous block device id
1640  *
1641  * @objectid:	tree objectid
1642  * @anon_dev:	if zero, allocate a new anonymous block device or use the
1643  *		parameter value
1644  */
1645 struct btrfs_root *btrfs_get_new_fs_root(struct btrfs_fs_info *fs_info,
1646 					 u64 objectid, dev_t anon_dev)
1647 {
1648 	return btrfs_get_root_ref(fs_info, objectid, anon_dev, true);
1649 }
1650 
1651 /*
1652  * btrfs_get_fs_root_commit_root - return a root for the given objectid
1653  * @fs_info:	the fs_info
1654  * @objectid:	the objectid we need to lookup
1655  *
1656  * This is exclusively used for backref walking, and exists specifically because
1657  * of how qgroups does lookups.  Qgroups will do a backref lookup at delayed ref
1658  * creation time, which means we may have to read the tree_root in order to look
1659  * up a fs root that is not in memory.  If the root is not in memory we will
1660  * read the tree root commit root and look up the fs root from there.  This is a
1661  * temporary root, it will not be inserted into the radix tree as it doesn't
1662  * have the most uptodate information, it'll simply be discarded once the
1663  * backref code is finished using the root.
1664  */
1665 struct btrfs_root *btrfs_get_fs_root_commit_root(struct btrfs_fs_info *fs_info,
1666 						 struct btrfs_path *path,
1667 						 u64 objectid)
1668 {
1669 	struct btrfs_root *root;
1670 	struct btrfs_key key;
1671 
1672 	ASSERT(path->search_commit_root && path->skip_locking);
1673 
1674 	/*
1675 	 * This can return -ENOENT if we ask for a root that doesn't exist, but
1676 	 * since this is called via the backref walking code we won't be looking
1677 	 * up a root that doesn't exist, unless there's corruption.  So if root
1678 	 * != NULL just return it.
1679 	 */
1680 	root = btrfs_get_global_root(fs_info, objectid);
1681 	if (root)
1682 		return root;
1683 
1684 	root = btrfs_lookup_fs_root(fs_info, objectid);
1685 	if (root)
1686 		return root;
1687 
1688 	key.objectid = objectid;
1689 	key.type = BTRFS_ROOT_ITEM_KEY;
1690 	key.offset = (u64)-1;
1691 	root = read_tree_root_path(fs_info->tree_root, path, &key);
1692 	btrfs_release_path(path);
1693 
1694 	return root;
1695 }
1696 
1697 static int cleaner_kthread(void *arg)
1698 {
1699 	struct btrfs_fs_info *fs_info = arg;
1700 	int again;
1701 
1702 	while (1) {
1703 		again = 0;
1704 
1705 		set_bit(BTRFS_FS_CLEANER_RUNNING, &fs_info->flags);
1706 
1707 		/* Make the cleaner go to sleep early. */
1708 		if (btrfs_need_cleaner_sleep(fs_info))
1709 			goto sleep;
1710 
1711 		/*
1712 		 * Do not do anything if we might cause open_ctree() to block
1713 		 * before we have finished mounting the filesystem.
1714 		 */
1715 		if (!test_bit(BTRFS_FS_OPEN, &fs_info->flags))
1716 			goto sleep;
1717 
1718 		if (!mutex_trylock(&fs_info->cleaner_mutex))
1719 			goto sleep;
1720 
1721 		/*
1722 		 * Avoid the problem that we change the status of the fs
1723 		 * during the above check and trylock.
1724 		 */
1725 		if (btrfs_need_cleaner_sleep(fs_info)) {
1726 			mutex_unlock(&fs_info->cleaner_mutex);
1727 			goto sleep;
1728 		}
1729 
1730 		if (test_and_clear_bit(BTRFS_FS_FEATURE_CHANGED, &fs_info->flags))
1731 			btrfs_sysfs_feature_update(fs_info);
1732 
1733 		btrfs_run_delayed_iputs(fs_info);
1734 
1735 		again = btrfs_clean_one_deleted_snapshot(fs_info);
1736 		mutex_unlock(&fs_info->cleaner_mutex);
1737 
1738 		/*
1739 		 * The defragger has dealt with the R/O remount and umount,
1740 		 * needn't do anything special here.
1741 		 */
1742 		btrfs_run_defrag_inodes(fs_info);
1743 
1744 		/*
1745 		 * Acquires fs_info->reclaim_bgs_lock to avoid racing
1746 		 * with relocation (btrfs_relocate_chunk) and relocation
1747 		 * acquires fs_info->cleaner_mutex (btrfs_relocate_block_group)
1748 		 * after acquiring fs_info->reclaim_bgs_lock. So we
1749 		 * can't hold, nor need to, fs_info->cleaner_mutex when deleting
1750 		 * unused block groups.
1751 		 */
1752 		btrfs_delete_unused_bgs(fs_info);
1753 
1754 		/*
1755 		 * Reclaim block groups in the reclaim_bgs list after we deleted
1756 		 * all unused block_groups. This possibly gives us some more free
1757 		 * space.
1758 		 */
1759 		btrfs_reclaim_bgs(fs_info);
1760 sleep:
1761 		clear_and_wake_up_bit(BTRFS_FS_CLEANER_RUNNING, &fs_info->flags);
1762 		if (kthread_should_park())
1763 			kthread_parkme();
1764 		if (kthread_should_stop())
1765 			return 0;
1766 		if (!again) {
1767 			set_current_state(TASK_INTERRUPTIBLE);
1768 			schedule();
1769 			__set_current_state(TASK_RUNNING);
1770 		}
1771 	}
1772 }
1773 
1774 static int transaction_kthread(void *arg)
1775 {
1776 	struct btrfs_root *root = arg;
1777 	struct btrfs_fs_info *fs_info = root->fs_info;
1778 	struct btrfs_trans_handle *trans;
1779 	struct btrfs_transaction *cur;
1780 	u64 transid;
1781 	time64_t delta;
1782 	unsigned long delay;
1783 	bool cannot_commit;
1784 
1785 	do {
1786 		cannot_commit = false;
1787 		delay = msecs_to_jiffies(fs_info->commit_interval * 1000);
1788 		mutex_lock(&fs_info->transaction_kthread_mutex);
1789 
1790 		spin_lock(&fs_info->trans_lock);
1791 		cur = fs_info->running_transaction;
1792 		if (!cur) {
1793 			spin_unlock(&fs_info->trans_lock);
1794 			goto sleep;
1795 		}
1796 
1797 		delta = ktime_get_seconds() - cur->start_time;
1798 		if (!test_and_clear_bit(BTRFS_FS_COMMIT_TRANS, &fs_info->flags) &&
1799 		    cur->state < TRANS_STATE_COMMIT_START &&
1800 		    delta < fs_info->commit_interval) {
1801 			spin_unlock(&fs_info->trans_lock);
1802 			delay -= msecs_to_jiffies((delta - 1) * 1000);
1803 			delay = min(delay,
1804 				    msecs_to_jiffies(fs_info->commit_interval * 1000));
1805 			goto sleep;
1806 		}
1807 		transid = cur->transid;
1808 		spin_unlock(&fs_info->trans_lock);
1809 
1810 		/* If the file system is aborted, this will always fail. */
1811 		trans = btrfs_attach_transaction(root);
1812 		if (IS_ERR(trans)) {
1813 			if (PTR_ERR(trans) != -ENOENT)
1814 				cannot_commit = true;
1815 			goto sleep;
1816 		}
1817 		if (transid == trans->transid) {
1818 			btrfs_commit_transaction(trans);
1819 		} else {
1820 			btrfs_end_transaction(trans);
1821 		}
1822 sleep:
1823 		wake_up_process(fs_info->cleaner_kthread);
1824 		mutex_unlock(&fs_info->transaction_kthread_mutex);
1825 
1826 		if (BTRFS_FS_ERROR(fs_info))
1827 			btrfs_cleanup_transaction(fs_info);
1828 		if (!kthread_should_stop() &&
1829 				(!btrfs_transaction_blocked(fs_info) ||
1830 				 cannot_commit))
1831 			schedule_timeout_interruptible(delay);
1832 	} while (!kthread_should_stop());
1833 	return 0;
1834 }
1835 
1836 /*
1837  * This will find the highest generation in the array of root backups.  The
1838  * index of the highest array is returned, or -EINVAL if we can't find
1839  * anything.
1840  *
1841  * We check to make sure the array is valid by comparing the
1842  * generation of the latest  root in the array with the generation
1843  * in the super block.  If they don't match we pitch it.
1844  */
1845 static int find_newest_super_backup(struct btrfs_fs_info *info)
1846 {
1847 	const u64 newest_gen = btrfs_super_generation(info->super_copy);
1848 	u64 cur;
1849 	struct btrfs_root_backup *root_backup;
1850 	int i;
1851 
1852 	for (i = 0; i < BTRFS_NUM_BACKUP_ROOTS; i++) {
1853 		root_backup = info->super_copy->super_roots + i;
1854 		cur = btrfs_backup_tree_root_gen(root_backup);
1855 		if (cur == newest_gen)
1856 			return i;
1857 	}
1858 
1859 	return -EINVAL;
1860 }
1861 
1862 /*
1863  * copy all the root pointers into the super backup array.
1864  * this will bump the backup pointer by one when it is
1865  * done
1866  */
1867 static void backup_super_roots(struct btrfs_fs_info *info)
1868 {
1869 	const int next_backup = info->backup_root_index;
1870 	struct btrfs_root_backup *root_backup;
1871 
1872 	root_backup = info->super_for_commit->super_roots + next_backup;
1873 
1874 	/*
1875 	 * make sure all of our padding and empty slots get zero filled
1876 	 * regardless of which ones we use today
1877 	 */
1878 	memset(root_backup, 0, sizeof(*root_backup));
1879 
1880 	info->backup_root_index = (next_backup + 1) % BTRFS_NUM_BACKUP_ROOTS;
1881 
1882 	btrfs_set_backup_tree_root(root_backup, info->tree_root->node->start);
1883 	btrfs_set_backup_tree_root_gen(root_backup,
1884 			       btrfs_header_generation(info->tree_root->node));
1885 
1886 	btrfs_set_backup_tree_root_level(root_backup,
1887 			       btrfs_header_level(info->tree_root->node));
1888 
1889 	btrfs_set_backup_chunk_root(root_backup, info->chunk_root->node->start);
1890 	btrfs_set_backup_chunk_root_gen(root_backup,
1891 			       btrfs_header_generation(info->chunk_root->node));
1892 	btrfs_set_backup_chunk_root_level(root_backup,
1893 			       btrfs_header_level(info->chunk_root->node));
1894 
1895 	if (!btrfs_fs_compat_ro(info, BLOCK_GROUP_TREE)) {
1896 		struct btrfs_root *extent_root = btrfs_extent_root(info, 0);
1897 		struct btrfs_root *csum_root = btrfs_csum_root(info, 0);
1898 
1899 		btrfs_set_backup_extent_root(root_backup,
1900 					     extent_root->node->start);
1901 		btrfs_set_backup_extent_root_gen(root_backup,
1902 				btrfs_header_generation(extent_root->node));
1903 		btrfs_set_backup_extent_root_level(root_backup,
1904 					btrfs_header_level(extent_root->node));
1905 
1906 		btrfs_set_backup_csum_root(root_backup, csum_root->node->start);
1907 		btrfs_set_backup_csum_root_gen(root_backup,
1908 					       btrfs_header_generation(csum_root->node));
1909 		btrfs_set_backup_csum_root_level(root_backup,
1910 						 btrfs_header_level(csum_root->node));
1911 	}
1912 
1913 	/*
1914 	 * we might commit during log recovery, which happens before we set
1915 	 * the fs_root.  Make sure it is valid before we fill it in.
1916 	 */
1917 	if (info->fs_root && info->fs_root->node) {
1918 		btrfs_set_backup_fs_root(root_backup,
1919 					 info->fs_root->node->start);
1920 		btrfs_set_backup_fs_root_gen(root_backup,
1921 			       btrfs_header_generation(info->fs_root->node));
1922 		btrfs_set_backup_fs_root_level(root_backup,
1923 			       btrfs_header_level(info->fs_root->node));
1924 	}
1925 
1926 	btrfs_set_backup_dev_root(root_backup, info->dev_root->node->start);
1927 	btrfs_set_backup_dev_root_gen(root_backup,
1928 			       btrfs_header_generation(info->dev_root->node));
1929 	btrfs_set_backup_dev_root_level(root_backup,
1930 				       btrfs_header_level(info->dev_root->node));
1931 
1932 	btrfs_set_backup_total_bytes(root_backup,
1933 			     btrfs_super_total_bytes(info->super_copy));
1934 	btrfs_set_backup_bytes_used(root_backup,
1935 			     btrfs_super_bytes_used(info->super_copy));
1936 	btrfs_set_backup_num_devices(root_backup,
1937 			     btrfs_super_num_devices(info->super_copy));
1938 
1939 	/*
1940 	 * if we don't copy this out to the super_copy, it won't get remembered
1941 	 * for the next commit
1942 	 */
1943 	memcpy(&info->super_copy->super_roots,
1944 	       &info->super_for_commit->super_roots,
1945 	       sizeof(*root_backup) * BTRFS_NUM_BACKUP_ROOTS);
1946 }
1947 
1948 /*
1949  * read_backup_root - Reads a backup root based on the passed priority. Prio 0
1950  * is the newest, prio 1/2/3 are 2nd newest/3rd newest/4th (oldest) backup roots
1951  *
1952  * fs_info - filesystem whose backup roots need to be read
1953  * priority - priority of backup root required
1954  *
1955  * Returns backup root index on success and -EINVAL otherwise.
1956  */
1957 static int read_backup_root(struct btrfs_fs_info *fs_info, u8 priority)
1958 {
1959 	int backup_index = find_newest_super_backup(fs_info);
1960 	struct btrfs_super_block *super = fs_info->super_copy;
1961 	struct btrfs_root_backup *root_backup;
1962 
1963 	if (priority < BTRFS_NUM_BACKUP_ROOTS && backup_index >= 0) {
1964 		if (priority == 0)
1965 			return backup_index;
1966 
1967 		backup_index = backup_index + BTRFS_NUM_BACKUP_ROOTS - priority;
1968 		backup_index %= BTRFS_NUM_BACKUP_ROOTS;
1969 	} else {
1970 		return -EINVAL;
1971 	}
1972 
1973 	root_backup = super->super_roots + backup_index;
1974 
1975 	btrfs_set_super_generation(super,
1976 				   btrfs_backup_tree_root_gen(root_backup));
1977 	btrfs_set_super_root(super, btrfs_backup_tree_root(root_backup));
1978 	btrfs_set_super_root_level(super,
1979 				   btrfs_backup_tree_root_level(root_backup));
1980 	btrfs_set_super_bytes_used(super, btrfs_backup_bytes_used(root_backup));
1981 
1982 	/*
1983 	 * Fixme: the total bytes and num_devices need to match or we should
1984 	 * need a fsck
1985 	 */
1986 	btrfs_set_super_total_bytes(super, btrfs_backup_total_bytes(root_backup));
1987 	btrfs_set_super_num_devices(super, btrfs_backup_num_devices(root_backup));
1988 
1989 	return backup_index;
1990 }
1991 
1992 /* helper to cleanup workers */
1993 static void btrfs_stop_all_workers(struct btrfs_fs_info *fs_info)
1994 {
1995 	btrfs_destroy_workqueue(fs_info->fixup_workers);
1996 	btrfs_destroy_workqueue(fs_info->delalloc_workers);
1997 	btrfs_destroy_workqueue(fs_info->hipri_workers);
1998 	btrfs_destroy_workqueue(fs_info->workers);
1999 	if (fs_info->endio_workers)
2000 		destroy_workqueue(fs_info->endio_workers);
2001 	if (fs_info->rmw_workers)
2002 		destroy_workqueue(fs_info->rmw_workers);
2003 	if (fs_info->compressed_write_workers)
2004 		destroy_workqueue(fs_info->compressed_write_workers);
2005 	btrfs_destroy_workqueue(fs_info->endio_write_workers);
2006 	btrfs_destroy_workqueue(fs_info->endio_freespace_worker);
2007 	btrfs_destroy_workqueue(fs_info->delayed_workers);
2008 	btrfs_destroy_workqueue(fs_info->caching_workers);
2009 	btrfs_destroy_workqueue(fs_info->flush_workers);
2010 	btrfs_destroy_workqueue(fs_info->qgroup_rescan_workers);
2011 	if (fs_info->discard_ctl.discard_workers)
2012 		destroy_workqueue(fs_info->discard_ctl.discard_workers);
2013 	/*
2014 	 * Now that all other work queues are destroyed, we can safely destroy
2015 	 * the queues used for metadata I/O, since tasks from those other work
2016 	 * queues can do metadata I/O operations.
2017 	 */
2018 	if (fs_info->endio_meta_workers)
2019 		destroy_workqueue(fs_info->endio_meta_workers);
2020 }
2021 
2022 static void free_root_extent_buffers(struct btrfs_root *root)
2023 {
2024 	if (root) {
2025 		free_extent_buffer(root->node);
2026 		free_extent_buffer(root->commit_root);
2027 		root->node = NULL;
2028 		root->commit_root = NULL;
2029 	}
2030 }
2031 
2032 static void free_global_root_pointers(struct btrfs_fs_info *fs_info)
2033 {
2034 	struct btrfs_root *root, *tmp;
2035 
2036 	rbtree_postorder_for_each_entry_safe(root, tmp,
2037 					     &fs_info->global_root_tree,
2038 					     rb_node)
2039 		free_root_extent_buffers(root);
2040 }
2041 
2042 /* helper to cleanup tree roots */
2043 static void free_root_pointers(struct btrfs_fs_info *info, bool free_chunk_root)
2044 {
2045 	free_root_extent_buffers(info->tree_root);
2046 
2047 	free_global_root_pointers(info);
2048 	free_root_extent_buffers(info->dev_root);
2049 	free_root_extent_buffers(info->quota_root);
2050 	free_root_extent_buffers(info->uuid_root);
2051 	free_root_extent_buffers(info->fs_root);
2052 	free_root_extent_buffers(info->data_reloc_root);
2053 	free_root_extent_buffers(info->block_group_root);
2054 	if (free_chunk_root)
2055 		free_root_extent_buffers(info->chunk_root);
2056 }
2057 
2058 void btrfs_put_root(struct btrfs_root *root)
2059 {
2060 	if (!root)
2061 		return;
2062 
2063 	if (refcount_dec_and_test(&root->refs)) {
2064 		WARN_ON(!RB_EMPTY_ROOT(&root->inode_tree));
2065 		WARN_ON(test_bit(BTRFS_ROOT_DEAD_RELOC_TREE, &root->state));
2066 		if (root->anon_dev)
2067 			free_anon_bdev(root->anon_dev);
2068 		btrfs_drew_lock_destroy(&root->snapshot_lock);
2069 		free_root_extent_buffers(root);
2070 #ifdef CONFIG_BTRFS_DEBUG
2071 		spin_lock(&root->fs_info->fs_roots_radix_lock);
2072 		list_del_init(&root->leak_list);
2073 		spin_unlock(&root->fs_info->fs_roots_radix_lock);
2074 #endif
2075 		kfree(root);
2076 	}
2077 }
2078 
2079 void btrfs_free_fs_roots(struct btrfs_fs_info *fs_info)
2080 {
2081 	int ret;
2082 	struct btrfs_root *gang[8];
2083 	int i;
2084 
2085 	while (!list_empty(&fs_info->dead_roots)) {
2086 		gang[0] = list_entry(fs_info->dead_roots.next,
2087 				     struct btrfs_root, root_list);
2088 		list_del(&gang[0]->root_list);
2089 
2090 		if (test_bit(BTRFS_ROOT_IN_RADIX, &gang[0]->state))
2091 			btrfs_drop_and_free_fs_root(fs_info, gang[0]);
2092 		btrfs_put_root(gang[0]);
2093 	}
2094 
2095 	while (1) {
2096 		ret = radix_tree_gang_lookup(&fs_info->fs_roots_radix,
2097 					     (void **)gang, 0,
2098 					     ARRAY_SIZE(gang));
2099 		if (!ret)
2100 			break;
2101 		for (i = 0; i < ret; i++)
2102 			btrfs_drop_and_free_fs_root(fs_info, gang[i]);
2103 	}
2104 }
2105 
2106 static void btrfs_init_scrub(struct btrfs_fs_info *fs_info)
2107 {
2108 	mutex_init(&fs_info->scrub_lock);
2109 	atomic_set(&fs_info->scrubs_running, 0);
2110 	atomic_set(&fs_info->scrub_pause_req, 0);
2111 	atomic_set(&fs_info->scrubs_paused, 0);
2112 	atomic_set(&fs_info->scrub_cancel_req, 0);
2113 	init_waitqueue_head(&fs_info->scrub_pause_wait);
2114 	refcount_set(&fs_info->scrub_workers_refcnt, 0);
2115 }
2116 
2117 static void btrfs_init_balance(struct btrfs_fs_info *fs_info)
2118 {
2119 	spin_lock_init(&fs_info->balance_lock);
2120 	mutex_init(&fs_info->balance_mutex);
2121 	atomic_set(&fs_info->balance_pause_req, 0);
2122 	atomic_set(&fs_info->balance_cancel_req, 0);
2123 	fs_info->balance_ctl = NULL;
2124 	init_waitqueue_head(&fs_info->balance_wait_q);
2125 	atomic_set(&fs_info->reloc_cancel_req, 0);
2126 }
2127 
2128 static void btrfs_init_btree_inode(struct btrfs_fs_info *fs_info)
2129 {
2130 	struct inode *inode = fs_info->btree_inode;
2131 	unsigned long hash = btrfs_inode_hash(BTRFS_BTREE_INODE_OBJECTID,
2132 					      fs_info->tree_root);
2133 
2134 	inode->i_ino = BTRFS_BTREE_INODE_OBJECTID;
2135 	set_nlink(inode, 1);
2136 	/*
2137 	 * we set the i_size on the btree inode to the max possible int.
2138 	 * the real end of the address space is determined by all of
2139 	 * the devices in the system
2140 	 */
2141 	inode->i_size = OFFSET_MAX;
2142 	inode->i_mapping->a_ops = &btree_aops;
2143 
2144 	RB_CLEAR_NODE(&BTRFS_I(inode)->rb_node);
2145 	extent_io_tree_init(fs_info, &BTRFS_I(inode)->io_tree,
2146 			    IO_TREE_BTREE_INODE_IO);
2147 	extent_map_tree_init(&BTRFS_I(inode)->extent_tree);
2148 
2149 	BTRFS_I(inode)->root = btrfs_grab_root(fs_info->tree_root);
2150 	BTRFS_I(inode)->location.objectid = BTRFS_BTREE_INODE_OBJECTID;
2151 	BTRFS_I(inode)->location.type = 0;
2152 	BTRFS_I(inode)->location.offset = 0;
2153 	set_bit(BTRFS_INODE_DUMMY, &BTRFS_I(inode)->runtime_flags);
2154 	__insert_inode_hash(inode, hash);
2155 }
2156 
2157 static void btrfs_init_dev_replace_locks(struct btrfs_fs_info *fs_info)
2158 {
2159 	mutex_init(&fs_info->dev_replace.lock_finishing_cancel_unmount);
2160 	init_rwsem(&fs_info->dev_replace.rwsem);
2161 	init_waitqueue_head(&fs_info->dev_replace.replace_wait);
2162 }
2163 
2164 static void btrfs_init_qgroup(struct btrfs_fs_info *fs_info)
2165 {
2166 	spin_lock_init(&fs_info->qgroup_lock);
2167 	mutex_init(&fs_info->qgroup_ioctl_lock);
2168 	fs_info->qgroup_tree = RB_ROOT;
2169 	INIT_LIST_HEAD(&fs_info->dirty_qgroups);
2170 	fs_info->qgroup_seq = 1;
2171 	fs_info->qgroup_ulist = NULL;
2172 	fs_info->qgroup_rescan_running = false;
2173 	fs_info->qgroup_drop_subtree_thres = BTRFS_MAX_LEVEL;
2174 	mutex_init(&fs_info->qgroup_rescan_lock);
2175 }
2176 
2177 static int btrfs_init_workqueues(struct btrfs_fs_info *fs_info)
2178 {
2179 	u32 max_active = fs_info->thread_pool_size;
2180 	unsigned int flags = WQ_MEM_RECLAIM | WQ_FREEZABLE | WQ_UNBOUND;
2181 
2182 	fs_info->workers =
2183 		btrfs_alloc_workqueue(fs_info, "worker", flags, max_active, 16);
2184 	fs_info->hipri_workers =
2185 		btrfs_alloc_workqueue(fs_info, "worker-high",
2186 				      flags | WQ_HIGHPRI, max_active, 16);
2187 
2188 	fs_info->delalloc_workers =
2189 		btrfs_alloc_workqueue(fs_info, "delalloc",
2190 				      flags, max_active, 2);
2191 
2192 	fs_info->flush_workers =
2193 		btrfs_alloc_workqueue(fs_info, "flush_delalloc",
2194 				      flags, max_active, 0);
2195 
2196 	fs_info->caching_workers =
2197 		btrfs_alloc_workqueue(fs_info, "cache", flags, max_active, 0);
2198 
2199 	fs_info->fixup_workers =
2200 		btrfs_alloc_workqueue(fs_info, "fixup", flags, 1, 0);
2201 
2202 	fs_info->endio_workers =
2203 		alloc_workqueue("btrfs-endio", flags, max_active);
2204 	fs_info->endio_meta_workers =
2205 		alloc_workqueue("btrfs-endio-meta", flags, max_active);
2206 	fs_info->rmw_workers = alloc_workqueue("btrfs-rmw", flags, max_active);
2207 	fs_info->endio_write_workers =
2208 		btrfs_alloc_workqueue(fs_info, "endio-write", flags,
2209 				      max_active, 2);
2210 	fs_info->compressed_write_workers =
2211 		alloc_workqueue("btrfs-compressed-write", flags, max_active);
2212 	fs_info->endio_freespace_worker =
2213 		btrfs_alloc_workqueue(fs_info, "freespace-write", flags,
2214 				      max_active, 0);
2215 	fs_info->delayed_workers =
2216 		btrfs_alloc_workqueue(fs_info, "delayed-meta", flags,
2217 				      max_active, 0);
2218 	fs_info->qgroup_rescan_workers =
2219 		btrfs_alloc_workqueue(fs_info, "qgroup-rescan", flags, 1, 0);
2220 	fs_info->discard_ctl.discard_workers =
2221 		alloc_workqueue("btrfs_discard", WQ_UNBOUND | WQ_FREEZABLE, 1);
2222 
2223 	if (!(fs_info->workers && fs_info->hipri_workers &&
2224 	      fs_info->delalloc_workers && fs_info->flush_workers &&
2225 	      fs_info->endio_workers && fs_info->endio_meta_workers &&
2226 	      fs_info->compressed_write_workers &&
2227 	      fs_info->endio_write_workers &&
2228 	      fs_info->endio_freespace_worker && fs_info->rmw_workers &&
2229 	      fs_info->caching_workers && fs_info->fixup_workers &&
2230 	      fs_info->delayed_workers && fs_info->qgroup_rescan_workers &&
2231 	      fs_info->discard_ctl.discard_workers)) {
2232 		return -ENOMEM;
2233 	}
2234 
2235 	return 0;
2236 }
2237 
2238 static int btrfs_init_csum_hash(struct btrfs_fs_info *fs_info, u16 csum_type)
2239 {
2240 	struct crypto_shash *csum_shash;
2241 	const char *csum_driver = btrfs_super_csum_driver(csum_type);
2242 
2243 	csum_shash = crypto_alloc_shash(csum_driver, 0, 0);
2244 
2245 	if (IS_ERR(csum_shash)) {
2246 		btrfs_err(fs_info, "error allocating %s hash for checksum",
2247 			  csum_driver);
2248 		return PTR_ERR(csum_shash);
2249 	}
2250 
2251 	fs_info->csum_shash = csum_shash;
2252 
2253 	/*
2254 	 * Check if the checksum implementation is a fast accelerated one.
2255 	 * As-is this is a bit of a hack and should be replaced once the csum
2256 	 * implementations provide that information themselves.
2257 	 */
2258 	switch (csum_type) {
2259 	case BTRFS_CSUM_TYPE_CRC32:
2260 		if (!strstr(crypto_shash_driver_name(csum_shash), "generic"))
2261 			set_bit(BTRFS_FS_CSUM_IMPL_FAST, &fs_info->flags);
2262 		break;
2263 	default:
2264 		break;
2265 	}
2266 
2267 	btrfs_info(fs_info, "using %s (%s) checksum algorithm",
2268 			btrfs_super_csum_name(csum_type),
2269 			crypto_shash_driver_name(csum_shash));
2270 	return 0;
2271 }
2272 
2273 static int btrfs_replay_log(struct btrfs_fs_info *fs_info,
2274 			    struct btrfs_fs_devices *fs_devices)
2275 {
2276 	int ret;
2277 	struct btrfs_tree_parent_check check = { 0 };
2278 	struct btrfs_root *log_tree_root;
2279 	struct btrfs_super_block *disk_super = fs_info->super_copy;
2280 	u64 bytenr = btrfs_super_log_root(disk_super);
2281 	int level = btrfs_super_log_root_level(disk_super);
2282 
2283 	if (fs_devices->rw_devices == 0) {
2284 		btrfs_warn(fs_info, "log replay required on RO media");
2285 		return -EIO;
2286 	}
2287 
2288 	log_tree_root = btrfs_alloc_root(fs_info, BTRFS_TREE_LOG_OBJECTID,
2289 					 GFP_KERNEL);
2290 	if (!log_tree_root)
2291 		return -ENOMEM;
2292 
2293 	check.level = level;
2294 	check.transid = fs_info->generation + 1;
2295 	check.owner_root = BTRFS_TREE_LOG_OBJECTID;
2296 	log_tree_root->node = read_tree_block(fs_info, bytenr, &check);
2297 	if (IS_ERR(log_tree_root->node)) {
2298 		btrfs_warn(fs_info, "failed to read log tree");
2299 		ret = PTR_ERR(log_tree_root->node);
2300 		log_tree_root->node = NULL;
2301 		btrfs_put_root(log_tree_root);
2302 		return ret;
2303 	}
2304 	if (!extent_buffer_uptodate(log_tree_root->node)) {
2305 		btrfs_err(fs_info, "failed to read log tree");
2306 		btrfs_put_root(log_tree_root);
2307 		return -EIO;
2308 	}
2309 
2310 	/* returns with log_tree_root freed on success */
2311 	ret = btrfs_recover_log_trees(log_tree_root);
2312 	if (ret) {
2313 		btrfs_handle_fs_error(fs_info, ret,
2314 				      "Failed to recover log tree");
2315 		btrfs_put_root(log_tree_root);
2316 		return ret;
2317 	}
2318 
2319 	if (sb_rdonly(fs_info->sb)) {
2320 		ret = btrfs_commit_super(fs_info);
2321 		if (ret)
2322 			return ret;
2323 	}
2324 
2325 	return 0;
2326 }
2327 
2328 static int load_global_roots_objectid(struct btrfs_root *tree_root,
2329 				      struct btrfs_path *path, u64 objectid,
2330 				      const char *name)
2331 {
2332 	struct btrfs_fs_info *fs_info = tree_root->fs_info;
2333 	struct btrfs_root *root;
2334 	u64 max_global_id = 0;
2335 	int ret;
2336 	struct btrfs_key key = {
2337 		.objectid = objectid,
2338 		.type = BTRFS_ROOT_ITEM_KEY,
2339 		.offset = 0,
2340 	};
2341 	bool found = false;
2342 
2343 	/* If we have IGNOREDATACSUMS skip loading these roots. */
2344 	if (objectid == BTRFS_CSUM_TREE_OBJECTID &&
2345 	    btrfs_test_opt(fs_info, IGNOREDATACSUMS)) {
2346 		set_bit(BTRFS_FS_STATE_NO_CSUMS, &fs_info->fs_state);
2347 		return 0;
2348 	}
2349 
2350 	while (1) {
2351 		ret = btrfs_search_slot(NULL, tree_root, &key, path, 0, 0);
2352 		if (ret < 0)
2353 			break;
2354 
2355 		if (path->slots[0] >= btrfs_header_nritems(path->nodes[0])) {
2356 			ret = btrfs_next_leaf(tree_root, path);
2357 			if (ret) {
2358 				if (ret > 0)
2359 					ret = 0;
2360 				break;
2361 			}
2362 		}
2363 		ret = 0;
2364 
2365 		btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
2366 		if (key.objectid != objectid)
2367 			break;
2368 		btrfs_release_path(path);
2369 
2370 		/*
2371 		 * Just worry about this for extent tree, it'll be the same for
2372 		 * everybody.
2373 		 */
2374 		if (objectid == BTRFS_EXTENT_TREE_OBJECTID)
2375 			max_global_id = max(max_global_id, key.offset);
2376 
2377 		found = true;
2378 		root = read_tree_root_path(tree_root, path, &key);
2379 		if (IS_ERR(root)) {
2380 			if (!btrfs_test_opt(fs_info, IGNOREBADROOTS))
2381 				ret = PTR_ERR(root);
2382 			break;
2383 		}
2384 		set_bit(BTRFS_ROOT_TRACK_DIRTY, &root->state);
2385 		ret = btrfs_global_root_insert(root);
2386 		if (ret) {
2387 			btrfs_put_root(root);
2388 			break;
2389 		}
2390 		key.offset++;
2391 	}
2392 	btrfs_release_path(path);
2393 
2394 	if (objectid == BTRFS_EXTENT_TREE_OBJECTID)
2395 		fs_info->nr_global_roots = max_global_id + 1;
2396 
2397 	if (!found || ret) {
2398 		if (objectid == BTRFS_CSUM_TREE_OBJECTID)
2399 			set_bit(BTRFS_FS_STATE_NO_CSUMS, &fs_info->fs_state);
2400 
2401 		if (!btrfs_test_opt(fs_info, IGNOREBADROOTS))
2402 			ret = ret ? ret : -ENOENT;
2403 		else
2404 			ret = 0;
2405 		btrfs_err(fs_info, "failed to load root %s", name);
2406 	}
2407 	return ret;
2408 }
2409 
2410 static int load_global_roots(struct btrfs_root *tree_root)
2411 {
2412 	struct btrfs_path *path;
2413 	int ret = 0;
2414 
2415 	path = btrfs_alloc_path();
2416 	if (!path)
2417 		return -ENOMEM;
2418 
2419 	ret = load_global_roots_objectid(tree_root, path,
2420 					 BTRFS_EXTENT_TREE_OBJECTID, "extent");
2421 	if (ret)
2422 		goto out;
2423 	ret = load_global_roots_objectid(tree_root, path,
2424 					 BTRFS_CSUM_TREE_OBJECTID, "csum");
2425 	if (ret)
2426 		goto out;
2427 	if (!btrfs_fs_compat_ro(tree_root->fs_info, FREE_SPACE_TREE))
2428 		goto out;
2429 	ret = load_global_roots_objectid(tree_root, path,
2430 					 BTRFS_FREE_SPACE_TREE_OBJECTID,
2431 					 "free space");
2432 out:
2433 	btrfs_free_path(path);
2434 	return ret;
2435 }
2436 
2437 static int btrfs_read_roots(struct btrfs_fs_info *fs_info)
2438 {
2439 	struct btrfs_root *tree_root = fs_info->tree_root;
2440 	struct btrfs_root *root;
2441 	struct btrfs_key location;
2442 	int ret;
2443 
2444 	BUG_ON(!fs_info->tree_root);
2445 
2446 	ret = load_global_roots(tree_root);
2447 	if (ret)
2448 		return ret;
2449 
2450 	location.type = BTRFS_ROOT_ITEM_KEY;
2451 	location.offset = 0;
2452 
2453 	if (btrfs_fs_compat_ro(fs_info, BLOCK_GROUP_TREE)) {
2454 		location.objectid = BTRFS_BLOCK_GROUP_TREE_OBJECTID;
2455 		root = btrfs_read_tree_root(tree_root, &location);
2456 		if (IS_ERR(root)) {
2457 			if (!btrfs_test_opt(fs_info, IGNOREBADROOTS)) {
2458 				ret = PTR_ERR(root);
2459 				goto out;
2460 			}
2461 		} else {
2462 			set_bit(BTRFS_ROOT_TRACK_DIRTY, &root->state);
2463 			fs_info->block_group_root = root;
2464 		}
2465 	}
2466 
2467 	location.objectid = BTRFS_DEV_TREE_OBJECTID;
2468 	root = btrfs_read_tree_root(tree_root, &location);
2469 	if (IS_ERR(root)) {
2470 		if (!btrfs_test_opt(fs_info, IGNOREBADROOTS)) {
2471 			ret = PTR_ERR(root);
2472 			goto out;
2473 		}
2474 	} else {
2475 		set_bit(BTRFS_ROOT_TRACK_DIRTY, &root->state);
2476 		fs_info->dev_root = root;
2477 	}
2478 	/* Initialize fs_info for all devices in any case */
2479 	ret = btrfs_init_devices_late(fs_info);
2480 	if (ret)
2481 		goto out;
2482 
2483 	/*
2484 	 * This tree can share blocks with some other fs tree during relocation
2485 	 * and we need a proper setup by btrfs_get_fs_root
2486 	 */
2487 	root = btrfs_get_fs_root(tree_root->fs_info,
2488 				 BTRFS_DATA_RELOC_TREE_OBJECTID, true);
2489 	if (IS_ERR(root)) {
2490 		if (!btrfs_test_opt(fs_info, IGNOREBADROOTS)) {
2491 			ret = PTR_ERR(root);
2492 			goto out;
2493 		}
2494 	} else {
2495 		set_bit(BTRFS_ROOT_TRACK_DIRTY, &root->state);
2496 		fs_info->data_reloc_root = root;
2497 	}
2498 
2499 	location.objectid = BTRFS_QUOTA_TREE_OBJECTID;
2500 	root = btrfs_read_tree_root(tree_root, &location);
2501 	if (!IS_ERR(root)) {
2502 		set_bit(BTRFS_ROOT_TRACK_DIRTY, &root->state);
2503 		set_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags);
2504 		fs_info->quota_root = root;
2505 	}
2506 
2507 	location.objectid = BTRFS_UUID_TREE_OBJECTID;
2508 	root = btrfs_read_tree_root(tree_root, &location);
2509 	if (IS_ERR(root)) {
2510 		if (!btrfs_test_opt(fs_info, IGNOREBADROOTS)) {
2511 			ret = PTR_ERR(root);
2512 			if (ret != -ENOENT)
2513 				goto out;
2514 		}
2515 	} else {
2516 		set_bit(BTRFS_ROOT_TRACK_DIRTY, &root->state);
2517 		fs_info->uuid_root = root;
2518 	}
2519 
2520 	return 0;
2521 out:
2522 	btrfs_warn(fs_info, "failed to read root (objectid=%llu): %d",
2523 		   location.objectid, ret);
2524 	return ret;
2525 }
2526 
2527 /*
2528  * Real super block validation
2529  * NOTE: super csum type and incompat features will not be checked here.
2530  *
2531  * @sb:		super block to check
2532  * @mirror_num:	the super block number to check its bytenr:
2533  * 		0	the primary (1st) sb
2534  * 		1, 2	2nd and 3rd backup copy
2535  * 	       -1	skip bytenr check
2536  */
2537 int btrfs_validate_super(struct btrfs_fs_info *fs_info,
2538 			 struct btrfs_super_block *sb, int mirror_num)
2539 {
2540 	u64 nodesize = btrfs_super_nodesize(sb);
2541 	u64 sectorsize = btrfs_super_sectorsize(sb);
2542 	int ret = 0;
2543 
2544 	if (btrfs_super_magic(sb) != BTRFS_MAGIC) {
2545 		btrfs_err(fs_info, "no valid FS found");
2546 		ret = -EINVAL;
2547 	}
2548 	if (btrfs_super_flags(sb) & ~BTRFS_SUPER_FLAG_SUPP) {
2549 		btrfs_err(fs_info, "unrecognized or unsupported super flag: %llu",
2550 				btrfs_super_flags(sb) & ~BTRFS_SUPER_FLAG_SUPP);
2551 		ret = -EINVAL;
2552 	}
2553 	if (btrfs_super_root_level(sb) >= BTRFS_MAX_LEVEL) {
2554 		btrfs_err(fs_info, "tree_root level too big: %d >= %d",
2555 				btrfs_super_root_level(sb), BTRFS_MAX_LEVEL);
2556 		ret = -EINVAL;
2557 	}
2558 	if (btrfs_super_chunk_root_level(sb) >= BTRFS_MAX_LEVEL) {
2559 		btrfs_err(fs_info, "chunk_root level too big: %d >= %d",
2560 				btrfs_super_chunk_root_level(sb), BTRFS_MAX_LEVEL);
2561 		ret = -EINVAL;
2562 	}
2563 	if (btrfs_super_log_root_level(sb) >= BTRFS_MAX_LEVEL) {
2564 		btrfs_err(fs_info, "log_root level too big: %d >= %d",
2565 				btrfs_super_log_root_level(sb), BTRFS_MAX_LEVEL);
2566 		ret = -EINVAL;
2567 	}
2568 
2569 	/*
2570 	 * Check sectorsize and nodesize first, other check will need it.
2571 	 * Check all possible sectorsize(4K, 8K, 16K, 32K, 64K) here.
2572 	 */
2573 	if (!is_power_of_2(sectorsize) || sectorsize < 4096 ||
2574 	    sectorsize > BTRFS_MAX_METADATA_BLOCKSIZE) {
2575 		btrfs_err(fs_info, "invalid sectorsize %llu", sectorsize);
2576 		ret = -EINVAL;
2577 	}
2578 
2579 	/*
2580 	 * We only support at most two sectorsizes: 4K and PAGE_SIZE.
2581 	 *
2582 	 * We can support 16K sectorsize with 64K page size without problem,
2583 	 * but such sectorsize/pagesize combination doesn't make much sense.
2584 	 * 4K will be our future standard, PAGE_SIZE is supported from the very
2585 	 * beginning.
2586 	 */
2587 	if (sectorsize > PAGE_SIZE || (sectorsize != SZ_4K && sectorsize != PAGE_SIZE)) {
2588 		btrfs_err(fs_info,
2589 			"sectorsize %llu not yet supported for page size %lu",
2590 			sectorsize, PAGE_SIZE);
2591 		ret = -EINVAL;
2592 	}
2593 
2594 	if (!is_power_of_2(nodesize) || nodesize < sectorsize ||
2595 	    nodesize > BTRFS_MAX_METADATA_BLOCKSIZE) {
2596 		btrfs_err(fs_info, "invalid nodesize %llu", nodesize);
2597 		ret = -EINVAL;
2598 	}
2599 	if (nodesize != le32_to_cpu(sb->__unused_leafsize)) {
2600 		btrfs_err(fs_info, "invalid leafsize %u, should be %llu",
2601 			  le32_to_cpu(sb->__unused_leafsize), nodesize);
2602 		ret = -EINVAL;
2603 	}
2604 
2605 	/* Root alignment check */
2606 	if (!IS_ALIGNED(btrfs_super_root(sb), sectorsize)) {
2607 		btrfs_warn(fs_info, "tree_root block unaligned: %llu",
2608 			   btrfs_super_root(sb));
2609 		ret = -EINVAL;
2610 	}
2611 	if (!IS_ALIGNED(btrfs_super_chunk_root(sb), sectorsize)) {
2612 		btrfs_warn(fs_info, "chunk_root block unaligned: %llu",
2613 			   btrfs_super_chunk_root(sb));
2614 		ret = -EINVAL;
2615 	}
2616 	if (!IS_ALIGNED(btrfs_super_log_root(sb), sectorsize)) {
2617 		btrfs_warn(fs_info, "log_root block unaligned: %llu",
2618 			   btrfs_super_log_root(sb));
2619 		ret = -EINVAL;
2620 	}
2621 
2622 	if (memcmp(fs_info->fs_devices->fsid, fs_info->super_copy->fsid,
2623 		   BTRFS_FSID_SIZE)) {
2624 		btrfs_err(fs_info,
2625 		"superblock fsid doesn't match fsid of fs_devices: %pU != %pU",
2626 			fs_info->super_copy->fsid, fs_info->fs_devices->fsid);
2627 		ret = -EINVAL;
2628 	}
2629 
2630 	if (btrfs_fs_incompat(fs_info, METADATA_UUID) &&
2631 	    memcmp(fs_info->fs_devices->metadata_uuid,
2632 		   fs_info->super_copy->metadata_uuid, BTRFS_FSID_SIZE)) {
2633 		btrfs_err(fs_info,
2634 "superblock metadata_uuid doesn't match metadata uuid of fs_devices: %pU != %pU",
2635 			fs_info->super_copy->metadata_uuid,
2636 			fs_info->fs_devices->metadata_uuid);
2637 		ret = -EINVAL;
2638 	}
2639 
2640 	/*
2641 	 * Artificial requirement for block-group-tree to force newer features
2642 	 * (free-space-tree, no-holes) so the test matrix is smaller.
2643 	 */
2644 	if (btrfs_fs_compat_ro(fs_info, BLOCK_GROUP_TREE) &&
2645 	    (!btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE_VALID) ||
2646 	     !btrfs_fs_incompat(fs_info, NO_HOLES))) {
2647 		btrfs_err(fs_info,
2648 		"block-group-tree feature requires fres-space-tree and no-holes");
2649 		ret = -EINVAL;
2650 	}
2651 
2652 	if (memcmp(fs_info->fs_devices->metadata_uuid, sb->dev_item.fsid,
2653 		   BTRFS_FSID_SIZE) != 0) {
2654 		btrfs_err(fs_info,
2655 			"dev_item UUID does not match metadata fsid: %pU != %pU",
2656 			fs_info->fs_devices->metadata_uuid, sb->dev_item.fsid);
2657 		ret = -EINVAL;
2658 	}
2659 
2660 	/*
2661 	 * Hint to catch really bogus numbers, bitflips or so, more exact checks are
2662 	 * done later
2663 	 */
2664 	if (btrfs_super_bytes_used(sb) < 6 * btrfs_super_nodesize(sb)) {
2665 		btrfs_err(fs_info, "bytes_used is too small %llu",
2666 			  btrfs_super_bytes_used(sb));
2667 		ret = -EINVAL;
2668 	}
2669 	if (!is_power_of_2(btrfs_super_stripesize(sb))) {
2670 		btrfs_err(fs_info, "invalid stripesize %u",
2671 			  btrfs_super_stripesize(sb));
2672 		ret = -EINVAL;
2673 	}
2674 	if (btrfs_super_num_devices(sb) > (1UL << 31))
2675 		btrfs_warn(fs_info, "suspicious number of devices: %llu",
2676 			   btrfs_super_num_devices(sb));
2677 	if (btrfs_super_num_devices(sb) == 0) {
2678 		btrfs_err(fs_info, "number of devices is 0");
2679 		ret = -EINVAL;
2680 	}
2681 
2682 	if (mirror_num >= 0 &&
2683 	    btrfs_super_bytenr(sb) != btrfs_sb_offset(mirror_num)) {
2684 		btrfs_err(fs_info, "super offset mismatch %llu != %u",
2685 			  btrfs_super_bytenr(sb), BTRFS_SUPER_INFO_OFFSET);
2686 		ret = -EINVAL;
2687 	}
2688 
2689 	/*
2690 	 * Obvious sys_chunk_array corruptions, it must hold at least one key
2691 	 * and one chunk
2692 	 */
2693 	if (btrfs_super_sys_array_size(sb) > BTRFS_SYSTEM_CHUNK_ARRAY_SIZE) {
2694 		btrfs_err(fs_info, "system chunk array too big %u > %u",
2695 			  btrfs_super_sys_array_size(sb),
2696 			  BTRFS_SYSTEM_CHUNK_ARRAY_SIZE);
2697 		ret = -EINVAL;
2698 	}
2699 	if (btrfs_super_sys_array_size(sb) < sizeof(struct btrfs_disk_key)
2700 			+ sizeof(struct btrfs_chunk)) {
2701 		btrfs_err(fs_info, "system chunk array too small %u < %zu",
2702 			  btrfs_super_sys_array_size(sb),
2703 			  sizeof(struct btrfs_disk_key)
2704 			  + sizeof(struct btrfs_chunk));
2705 		ret = -EINVAL;
2706 	}
2707 
2708 	/*
2709 	 * The generation is a global counter, we'll trust it more than the others
2710 	 * but it's still possible that it's the one that's wrong.
2711 	 */
2712 	if (btrfs_super_generation(sb) < btrfs_super_chunk_root_generation(sb))
2713 		btrfs_warn(fs_info,
2714 			"suspicious: generation < chunk_root_generation: %llu < %llu",
2715 			btrfs_super_generation(sb),
2716 			btrfs_super_chunk_root_generation(sb));
2717 	if (btrfs_super_generation(sb) < btrfs_super_cache_generation(sb)
2718 	    && btrfs_super_cache_generation(sb) != (u64)-1)
2719 		btrfs_warn(fs_info,
2720 			"suspicious: generation < cache_generation: %llu < %llu",
2721 			btrfs_super_generation(sb),
2722 			btrfs_super_cache_generation(sb));
2723 
2724 	return ret;
2725 }
2726 
2727 /*
2728  * Validation of super block at mount time.
2729  * Some checks already done early at mount time, like csum type and incompat
2730  * flags will be skipped.
2731  */
2732 static int btrfs_validate_mount_super(struct btrfs_fs_info *fs_info)
2733 {
2734 	return btrfs_validate_super(fs_info, fs_info->super_copy, 0);
2735 }
2736 
2737 /*
2738  * Validation of super block at write time.
2739  * Some checks like bytenr check will be skipped as their values will be
2740  * overwritten soon.
2741  * Extra checks like csum type and incompat flags will be done here.
2742  */
2743 static int btrfs_validate_write_super(struct btrfs_fs_info *fs_info,
2744 				      struct btrfs_super_block *sb)
2745 {
2746 	int ret;
2747 
2748 	ret = btrfs_validate_super(fs_info, sb, -1);
2749 	if (ret < 0)
2750 		goto out;
2751 	if (!btrfs_supported_super_csum(btrfs_super_csum_type(sb))) {
2752 		ret = -EUCLEAN;
2753 		btrfs_err(fs_info, "invalid csum type, has %u want %u",
2754 			  btrfs_super_csum_type(sb), BTRFS_CSUM_TYPE_CRC32);
2755 		goto out;
2756 	}
2757 	if (btrfs_super_incompat_flags(sb) & ~BTRFS_FEATURE_INCOMPAT_SUPP) {
2758 		ret = -EUCLEAN;
2759 		btrfs_err(fs_info,
2760 		"invalid incompat flags, has 0x%llx valid mask 0x%llx",
2761 			  btrfs_super_incompat_flags(sb),
2762 			  (unsigned long long)BTRFS_FEATURE_INCOMPAT_SUPP);
2763 		goto out;
2764 	}
2765 out:
2766 	if (ret < 0)
2767 		btrfs_err(fs_info,
2768 		"super block corruption detected before writing it to disk");
2769 	return ret;
2770 }
2771 
2772 static int load_super_root(struct btrfs_root *root, u64 bytenr, u64 gen, int level)
2773 {
2774 	struct btrfs_tree_parent_check check = {
2775 		.level = level,
2776 		.transid = gen,
2777 		.owner_root = root->root_key.objectid
2778 	};
2779 	int ret = 0;
2780 
2781 	root->node = read_tree_block(root->fs_info, bytenr, &check);
2782 	if (IS_ERR(root->node)) {
2783 		ret = PTR_ERR(root->node);
2784 		root->node = NULL;
2785 		return ret;
2786 	}
2787 	if (!extent_buffer_uptodate(root->node)) {
2788 		free_extent_buffer(root->node);
2789 		root->node = NULL;
2790 		return -EIO;
2791 	}
2792 
2793 	btrfs_set_root_node(&root->root_item, root->node);
2794 	root->commit_root = btrfs_root_node(root);
2795 	btrfs_set_root_refs(&root->root_item, 1);
2796 	return ret;
2797 }
2798 
2799 static int load_important_roots(struct btrfs_fs_info *fs_info)
2800 {
2801 	struct btrfs_super_block *sb = fs_info->super_copy;
2802 	u64 gen, bytenr;
2803 	int level, ret;
2804 
2805 	bytenr = btrfs_super_root(sb);
2806 	gen = btrfs_super_generation(sb);
2807 	level = btrfs_super_root_level(sb);
2808 	ret = load_super_root(fs_info->tree_root, bytenr, gen, level);
2809 	if (ret) {
2810 		btrfs_warn(fs_info, "couldn't read tree root");
2811 		return ret;
2812 	}
2813 	return 0;
2814 }
2815 
2816 static int __cold init_tree_roots(struct btrfs_fs_info *fs_info)
2817 {
2818 	int backup_index = find_newest_super_backup(fs_info);
2819 	struct btrfs_super_block *sb = fs_info->super_copy;
2820 	struct btrfs_root *tree_root = fs_info->tree_root;
2821 	bool handle_error = false;
2822 	int ret = 0;
2823 	int i;
2824 
2825 	for (i = 0; i < BTRFS_NUM_BACKUP_ROOTS; i++) {
2826 		if (handle_error) {
2827 			if (!IS_ERR(tree_root->node))
2828 				free_extent_buffer(tree_root->node);
2829 			tree_root->node = NULL;
2830 
2831 			if (!btrfs_test_opt(fs_info, USEBACKUPROOT))
2832 				break;
2833 
2834 			free_root_pointers(fs_info, 0);
2835 
2836 			/*
2837 			 * Don't use the log in recovery mode, it won't be
2838 			 * valid
2839 			 */
2840 			btrfs_set_super_log_root(sb, 0);
2841 
2842 			/* We can't trust the free space cache either */
2843 			btrfs_set_opt(fs_info->mount_opt, CLEAR_CACHE);
2844 
2845 			ret = read_backup_root(fs_info, i);
2846 			backup_index = ret;
2847 			if (ret < 0)
2848 				return ret;
2849 		}
2850 
2851 		ret = load_important_roots(fs_info);
2852 		if (ret) {
2853 			handle_error = true;
2854 			continue;
2855 		}
2856 
2857 		/*
2858 		 * No need to hold btrfs_root::objectid_mutex since the fs
2859 		 * hasn't been fully initialised and we are the only user
2860 		 */
2861 		ret = btrfs_init_root_free_objectid(tree_root);
2862 		if (ret < 0) {
2863 			handle_error = true;
2864 			continue;
2865 		}
2866 
2867 		ASSERT(tree_root->free_objectid <= BTRFS_LAST_FREE_OBJECTID);
2868 
2869 		ret = btrfs_read_roots(fs_info);
2870 		if (ret < 0) {
2871 			handle_error = true;
2872 			continue;
2873 		}
2874 
2875 		/* All successful */
2876 		fs_info->generation = btrfs_header_generation(tree_root->node);
2877 		fs_info->last_trans_committed = fs_info->generation;
2878 		fs_info->last_reloc_trans = 0;
2879 
2880 		/* Always begin writing backup roots after the one being used */
2881 		if (backup_index < 0) {
2882 			fs_info->backup_root_index = 0;
2883 		} else {
2884 			fs_info->backup_root_index = backup_index + 1;
2885 			fs_info->backup_root_index %= BTRFS_NUM_BACKUP_ROOTS;
2886 		}
2887 		break;
2888 	}
2889 
2890 	return ret;
2891 }
2892 
2893 void btrfs_init_fs_info(struct btrfs_fs_info *fs_info)
2894 {
2895 	INIT_RADIX_TREE(&fs_info->fs_roots_radix, GFP_ATOMIC);
2896 	INIT_RADIX_TREE(&fs_info->buffer_radix, GFP_ATOMIC);
2897 	INIT_LIST_HEAD(&fs_info->trans_list);
2898 	INIT_LIST_HEAD(&fs_info->dead_roots);
2899 	INIT_LIST_HEAD(&fs_info->delayed_iputs);
2900 	INIT_LIST_HEAD(&fs_info->delalloc_roots);
2901 	INIT_LIST_HEAD(&fs_info->caching_block_groups);
2902 	spin_lock_init(&fs_info->delalloc_root_lock);
2903 	spin_lock_init(&fs_info->trans_lock);
2904 	spin_lock_init(&fs_info->fs_roots_radix_lock);
2905 	spin_lock_init(&fs_info->delayed_iput_lock);
2906 	spin_lock_init(&fs_info->defrag_inodes_lock);
2907 	spin_lock_init(&fs_info->super_lock);
2908 	spin_lock_init(&fs_info->buffer_lock);
2909 	spin_lock_init(&fs_info->unused_bgs_lock);
2910 	spin_lock_init(&fs_info->treelog_bg_lock);
2911 	spin_lock_init(&fs_info->zone_active_bgs_lock);
2912 	spin_lock_init(&fs_info->relocation_bg_lock);
2913 	rwlock_init(&fs_info->tree_mod_log_lock);
2914 	rwlock_init(&fs_info->global_root_lock);
2915 	mutex_init(&fs_info->unused_bg_unpin_mutex);
2916 	mutex_init(&fs_info->reclaim_bgs_lock);
2917 	mutex_init(&fs_info->reloc_mutex);
2918 	mutex_init(&fs_info->delalloc_root_mutex);
2919 	mutex_init(&fs_info->zoned_meta_io_lock);
2920 	mutex_init(&fs_info->zoned_data_reloc_io_lock);
2921 	seqlock_init(&fs_info->profiles_lock);
2922 
2923 	btrfs_lockdep_init_map(fs_info, btrfs_trans_num_writers);
2924 	btrfs_lockdep_init_map(fs_info, btrfs_trans_num_extwriters);
2925 	btrfs_lockdep_init_map(fs_info, btrfs_trans_pending_ordered);
2926 	btrfs_lockdep_init_map(fs_info, btrfs_ordered_extent);
2927 	btrfs_state_lockdep_init_map(fs_info, btrfs_trans_commit_start,
2928 				     BTRFS_LOCKDEP_TRANS_COMMIT_START);
2929 	btrfs_state_lockdep_init_map(fs_info, btrfs_trans_unblocked,
2930 				     BTRFS_LOCKDEP_TRANS_UNBLOCKED);
2931 	btrfs_state_lockdep_init_map(fs_info, btrfs_trans_super_committed,
2932 				     BTRFS_LOCKDEP_TRANS_SUPER_COMMITTED);
2933 	btrfs_state_lockdep_init_map(fs_info, btrfs_trans_completed,
2934 				     BTRFS_LOCKDEP_TRANS_COMPLETED);
2935 
2936 	INIT_LIST_HEAD(&fs_info->dirty_cowonly_roots);
2937 	INIT_LIST_HEAD(&fs_info->space_info);
2938 	INIT_LIST_HEAD(&fs_info->tree_mod_seq_list);
2939 	INIT_LIST_HEAD(&fs_info->unused_bgs);
2940 	INIT_LIST_HEAD(&fs_info->reclaim_bgs);
2941 	INIT_LIST_HEAD(&fs_info->zone_active_bgs);
2942 #ifdef CONFIG_BTRFS_DEBUG
2943 	INIT_LIST_HEAD(&fs_info->allocated_roots);
2944 	INIT_LIST_HEAD(&fs_info->allocated_ebs);
2945 	spin_lock_init(&fs_info->eb_leak_lock);
2946 #endif
2947 	extent_map_tree_init(&fs_info->mapping_tree);
2948 	btrfs_init_block_rsv(&fs_info->global_block_rsv,
2949 			     BTRFS_BLOCK_RSV_GLOBAL);
2950 	btrfs_init_block_rsv(&fs_info->trans_block_rsv, BTRFS_BLOCK_RSV_TRANS);
2951 	btrfs_init_block_rsv(&fs_info->chunk_block_rsv, BTRFS_BLOCK_RSV_CHUNK);
2952 	btrfs_init_block_rsv(&fs_info->empty_block_rsv, BTRFS_BLOCK_RSV_EMPTY);
2953 	btrfs_init_block_rsv(&fs_info->delayed_block_rsv,
2954 			     BTRFS_BLOCK_RSV_DELOPS);
2955 	btrfs_init_block_rsv(&fs_info->delayed_refs_rsv,
2956 			     BTRFS_BLOCK_RSV_DELREFS);
2957 
2958 	atomic_set(&fs_info->async_delalloc_pages, 0);
2959 	atomic_set(&fs_info->defrag_running, 0);
2960 	atomic_set(&fs_info->nr_delayed_iputs, 0);
2961 	atomic64_set(&fs_info->tree_mod_seq, 0);
2962 	fs_info->global_root_tree = RB_ROOT;
2963 	fs_info->max_inline = BTRFS_DEFAULT_MAX_INLINE;
2964 	fs_info->metadata_ratio = 0;
2965 	fs_info->defrag_inodes = RB_ROOT;
2966 	atomic64_set(&fs_info->free_chunk_space, 0);
2967 	fs_info->tree_mod_log = RB_ROOT;
2968 	fs_info->commit_interval = BTRFS_DEFAULT_COMMIT_INTERVAL;
2969 	fs_info->avg_delayed_ref_runtime = NSEC_PER_SEC >> 6; /* div by 64 */
2970 	btrfs_init_ref_verify(fs_info);
2971 
2972 	fs_info->thread_pool_size = min_t(unsigned long,
2973 					  num_online_cpus() + 2, 8);
2974 
2975 	INIT_LIST_HEAD(&fs_info->ordered_roots);
2976 	spin_lock_init(&fs_info->ordered_root_lock);
2977 
2978 	btrfs_init_scrub(fs_info);
2979 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
2980 	fs_info->check_integrity_print_mask = 0;
2981 #endif
2982 	btrfs_init_balance(fs_info);
2983 	btrfs_init_async_reclaim_work(fs_info);
2984 
2985 	rwlock_init(&fs_info->block_group_cache_lock);
2986 	fs_info->block_group_cache_tree = RB_ROOT_CACHED;
2987 
2988 	extent_io_tree_init(fs_info, &fs_info->excluded_extents,
2989 			    IO_TREE_FS_EXCLUDED_EXTENTS);
2990 
2991 	mutex_init(&fs_info->ordered_operations_mutex);
2992 	mutex_init(&fs_info->tree_log_mutex);
2993 	mutex_init(&fs_info->chunk_mutex);
2994 	mutex_init(&fs_info->transaction_kthread_mutex);
2995 	mutex_init(&fs_info->cleaner_mutex);
2996 	mutex_init(&fs_info->ro_block_group_mutex);
2997 	init_rwsem(&fs_info->commit_root_sem);
2998 	init_rwsem(&fs_info->cleanup_work_sem);
2999 	init_rwsem(&fs_info->subvol_sem);
3000 	sema_init(&fs_info->uuid_tree_rescan_sem, 1);
3001 
3002 	btrfs_init_dev_replace_locks(fs_info);
3003 	btrfs_init_qgroup(fs_info);
3004 	btrfs_discard_init(fs_info);
3005 
3006 	btrfs_init_free_cluster(&fs_info->meta_alloc_cluster);
3007 	btrfs_init_free_cluster(&fs_info->data_alloc_cluster);
3008 
3009 	init_waitqueue_head(&fs_info->transaction_throttle);
3010 	init_waitqueue_head(&fs_info->transaction_wait);
3011 	init_waitqueue_head(&fs_info->transaction_blocked_wait);
3012 	init_waitqueue_head(&fs_info->async_submit_wait);
3013 	init_waitqueue_head(&fs_info->delayed_iputs_wait);
3014 
3015 	/* Usable values until the real ones are cached from the superblock */
3016 	fs_info->nodesize = 4096;
3017 	fs_info->sectorsize = 4096;
3018 	fs_info->sectorsize_bits = ilog2(4096);
3019 	fs_info->stripesize = 4096;
3020 
3021 	fs_info->max_extent_size = BTRFS_MAX_EXTENT_SIZE;
3022 
3023 	spin_lock_init(&fs_info->swapfile_pins_lock);
3024 	fs_info->swapfile_pins = RB_ROOT;
3025 
3026 	fs_info->bg_reclaim_threshold = BTRFS_DEFAULT_RECLAIM_THRESH;
3027 	INIT_WORK(&fs_info->reclaim_bgs_work, btrfs_reclaim_bgs_work);
3028 }
3029 
3030 static int init_mount_fs_info(struct btrfs_fs_info *fs_info, struct super_block *sb)
3031 {
3032 	int ret;
3033 
3034 	fs_info->sb = sb;
3035 	sb->s_blocksize = BTRFS_BDEV_BLOCKSIZE;
3036 	sb->s_blocksize_bits = blksize_bits(BTRFS_BDEV_BLOCKSIZE);
3037 
3038 	ret = percpu_counter_init(&fs_info->ordered_bytes, 0, GFP_KERNEL);
3039 	if (ret)
3040 		return ret;
3041 
3042 	ret = percpu_counter_init(&fs_info->dirty_metadata_bytes, 0, GFP_KERNEL);
3043 	if (ret)
3044 		return ret;
3045 
3046 	fs_info->dirty_metadata_batch = PAGE_SIZE *
3047 					(1 + ilog2(nr_cpu_ids));
3048 
3049 	ret = percpu_counter_init(&fs_info->delalloc_bytes, 0, GFP_KERNEL);
3050 	if (ret)
3051 		return ret;
3052 
3053 	ret = percpu_counter_init(&fs_info->dev_replace.bio_counter, 0,
3054 			GFP_KERNEL);
3055 	if (ret)
3056 		return ret;
3057 
3058 	fs_info->delayed_root = kmalloc(sizeof(struct btrfs_delayed_root),
3059 					GFP_KERNEL);
3060 	if (!fs_info->delayed_root)
3061 		return -ENOMEM;
3062 	btrfs_init_delayed_root(fs_info->delayed_root);
3063 
3064 	if (sb_rdonly(sb))
3065 		set_bit(BTRFS_FS_STATE_RO, &fs_info->fs_state);
3066 
3067 	return btrfs_alloc_stripe_hash_table(fs_info);
3068 }
3069 
3070 static int btrfs_uuid_rescan_kthread(void *data)
3071 {
3072 	struct btrfs_fs_info *fs_info = data;
3073 	int ret;
3074 
3075 	/*
3076 	 * 1st step is to iterate through the existing UUID tree and
3077 	 * to delete all entries that contain outdated data.
3078 	 * 2nd step is to add all missing entries to the UUID tree.
3079 	 */
3080 	ret = btrfs_uuid_tree_iterate(fs_info);
3081 	if (ret < 0) {
3082 		if (ret != -EINTR)
3083 			btrfs_warn(fs_info, "iterating uuid_tree failed %d",
3084 				   ret);
3085 		up(&fs_info->uuid_tree_rescan_sem);
3086 		return ret;
3087 	}
3088 	return btrfs_uuid_scan_kthread(data);
3089 }
3090 
3091 static int btrfs_check_uuid_tree(struct btrfs_fs_info *fs_info)
3092 {
3093 	struct task_struct *task;
3094 
3095 	down(&fs_info->uuid_tree_rescan_sem);
3096 	task = kthread_run(btrfs_uuid_rescan_kthread, fs_info, "btrfs-uuid");
3097 	if (IS_ERR(task)) {
3098 		/* fs_info->update_uuid_tree_gen remains 0 in all error case */
3099 		btrfs_warn(fs_info, "failed to start uuid_rescan task");
3100 		up(&fs_info->uuid_tree_rescan_sem);
3101 		return PTR_ERR(task);
3102 	}
3103 
3104 	return 0;
3105 }
3106 
3107 /*
3108  * Some options only have meaning at mount time and shouldn't persist across
3109  * remounts, or be displayed. Clear these at the end of mount and remount
3110  * code paths.
3111  */
3112 void btrfs_clear_oneshot_options(struct btrfs_fs_info *fs_info)
3113 {
3114 	btrfs_clear_opt(fs_info->mount_opt, USEBACKUPROOT);
3115 	btrfs_clear_opt(fs_info->mount_opt, CLEAR_CACHE);
3116 }
3117 
3118 /*
3119  * Mounting logic specific to read-write file systems. Shared by open_ctree
3120  * and btrfs_remount when remounting from read-only to read-write.
3121  */
3122 int btrfs_start_pre_rw_mount(struct btrfs_fs_info *fs_info)
3123 {
3124 	int ret;
3125 	const bool cache_opt = btrfs_test_opt(fs_info, SPACE_CACHE);
3126 	bool clear_free_space_tree = false;
3127 
3128 	if (btrfs_test_opt(fs_info, CLEAR_CACHE) &&
3129 	    btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE)) {
3130 		clear_free_space_tree = true;
3131 	} else if (btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE) &&
3132 		   !btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE_VALID)) {
3133 		btrfs_warn(fs_info, "free space tree is invalid");
3134 		clear_free_space_tree = true;
3135 	}
3136 
3137 	if (clear_free_space_tree) {
3138 		btrfs_info(fs_info, "clearing free space tree");
3139 		ret = btrfs_clear_free_space_tree(fs_info);
3140 		if (ret) {
3141 			btrfs_warn(fs_info,
3142 				   "failed to clear free space tree: %d", ret);
3143 			goto out;
3144 		}
3145 	}
3146 
3147 	/*
3148 	 * btrfs_find_orphan_roots() is responsible for finding all the dead
3149 	 * roots (with 0 refs), flag them with BTRFS_ROOT_DEAD_TREE and load
3150 	 * them into the fs_info->fs_roots_radix tree. This must be done before
3151 	 * calling btrfs_orphan_cleanup() on the tree root. If we don't do it
3152 	 * first, then btrfs_orphan_cleanup() will delete a dead root's orphan
3153 	 * item before the root's tree is deleted - this means that if we unmount
3154 	 * or crash before the deletion completes, on the next mount we will not
3155 	 * delete what remains of the tree because the orphan item does not
3156 	 * exists anymore, which is what tells us we have a pending deletion.
3157 	 */
3158 	ret = btrfs_find_orphan_roots(fs_info);
3159 	if (ret)
3160 		goto out;
3161 
3162 	ret = btrfs_cleanup_fs_roots(fs_info);
3163 	if (ret)
3164 		goto out;
3165 
3166 	down_read(&fs_info->cleanup_work_sem);
3167 	if ((ret = btrfs_orphan_cleanup(fs_info->fs_root)) ||
3168 	    (ret = btrfs_orphan_cleanup(fs_info->tree_root))) {
3169 		up_read(&fs_info->cleanup_work_sem);
3170 		goto out;
3171 	}
3172 	up_read(&fs_info->cleanup_work_sem);
3173 
3174 	mutex_lock(&fs_info->cleaner_mutex);
3175 	ret = btrfs_recover_relocation(fs_info);
3176 	mutex_unlock(&fs_info->cleaner_mutex);
3177 	if (ret < 0) {
3178 		btrfs_warn(fs_info, "failed to recover relocation: %d", ret);
3179 		goto out;
3180 	}
3181 
3182 	if (btrfs_test_opt(fs_info, FREE_SPACE_TREE) &&
3183 	    !btrfs_fs_compat_ro(fs_info, FREE_SPACE_TREE)) {
3184 		btrfs_info(fs_info, "creating free space tree");
3185 		ret = btrfs_create_free_space_tree(fs_info);
3186 		if (ret) {
3187 			btrfs_warn(fs_info,
3188 				"failed to create free space tree: %d", ret);
3189 			goto out;
3190 		}
3191 	}
3192 
3193 	if (cache_opt != btrfs_free_space_cache_v1_active(fs_info)) {
3194 		ret = btrfs_set_free_space_cache_v1_active(fs_info, cache_opt);
3195 		if (ret)
3196 			goto out;
3197 	}
3198 
3199 	ret = btrfs_resume_balance_async(fs_info);
3200 	if (ret)
3201 		goto out;
3202 
3203 	ret = btrfs_resume_dev_replace_async(fs_info);
3204 	if (ret) {
3205 		btrfs_warn(fs_info, "failed to resume dev_replace");
3206 		goto out;
3207 	}
3208 
3209 	btrfs_qgroup_rescan_resume(fs_info);
3210 
3211 	if (!fs_info->uuid_root) {
3212 		btrfs_info(fs_info, "creating UUID tree");
3213 		ret = btrfs_create_uuid_tree(fs_info);
3214 		if (ret) {
3215 			btrfs_warn(fs_info,
3216 				   "failed to create the UUID tree %d", ret);
3217 			goto out;
3218 		}
3219 	}
3220 
3221 out:
3222 	return ret;
3223 }
3224 
3225 /*
3226  * Do various sanity and dependency checks of different features.
3227  *
3228  * @is_rw_mount:	If the mount is read-write.
3229  *
3230  * This is the place for less strict checks (like for subpage or artificial
3231  * feature dependencies).
3232  *
3233  * For strict checks or possible corruption detection, see
3234  * btrfs_validate_super().
3235  *
3236  * This should be called after btrfs_parse_options(), as some mount options
3237  * (space cache related) can modify on-disk format like free space tree and
3238  * screw up certain feature dependencies.
3239  */
3240 int btrfs_check_features(struct btrfs_fs_info *fs_info, bool is_rw_mount)
3241 {
3242 	struct btrfs_super_block *disk_super = fs_info->super_copy;
3243 	u64 incompat = btrfs_super_incompat_flags(disk_super);
3244 	const u64 compat_ro = btrfs_super_compat_ro_flags(disk_super);
3245 	const u64 compat_ro_unsupp = (compat_ro & ~BTRFS_FEATURE_COMPAT_RO_SUPP);
3246 
3247 	if (incompat & ~BTRFS_FEATURE_INCOMPAT_SUPP) {
3248 		btrfs_err(fs_info,
3249 		"cannot mount because of unknown incompat features (0x%llx)",
3250 		    incompat);
3251 		return -EINVAL;
3252 	}
3253 
3254 	/* Runtime limitation for mixed block groups. */
3255 	if ((incompat & BTRFS_FEATURE_INCOMPAT_MIXED_GROUPS) &&
3256 	    (fs_info->sectorsize != fs_info->nodesize)) {
3257 		btrfs_err(fs_info,
3258 "unequal nodesize/sectorsize (%u != %u) are not allowed for mixed block groups",
3259 			fs_info->nodesize, fs_info->sectorsize);
3260 		return -EINVAL;
3261 	}
3262 
3263 	/* Mixed backref is an always-enabled feature. */
3264 	incompat |= BTRFS_FEATURE_INCOMPAT_MIXED_BACKREF;
3265 
3266 	/* Set compression related flags just in case. */
3267 	if (fs_info->compress_type == BTRFS_COMPRESS_LZO)
3268 		incompat |= BTRFS_FEATURE_INCOMPAT_COMPRESS_LZO;
3269 	else if (fs_info->compress_type == BTRFS_COMPRESS_ZSTD)
3270 		incompat |= BTRFS_FEATURE_INCOMPAT_COMPRESS_ZSTD;
3271 
3272 	/*
3273 	 * An ancient flag, which should really be marked deprecated.
3274 	 * Such runtime limitation doesn't really need a incompat flag.
3275 	 */
3276 	if (btrfs_super_nodesize(disk_super) > PAGE_SIZE)
3277 		incompat |= BTRFS_FEATURE_INCOMPAT_BIG_METADATA;
3278 
3279 	if (compat_ro_unsupp && is_rw_mount) {
3280 		btrfs_err(fs_info,
3281 	"cannot mount read-write because of unknown compat_ro features (0x%llx)",
3282 		       compat_ro);
3283 		return -EINVAL;
3284 	}
3285 
3286 	/*
3287 	 * We have unsupported RO compat features, although RO mounted, we
3288 	 * should not cause any metadata writes, including log replay.
3289 	 * Or we could screw up whatever the new feature requires.
3290 	 */
3291 	if (compat_ro_unsupp && btrfs_super_log_root(disk_super) &&
3292 	    !btrfs_test_opt(fs_info, NOLOGREPLAY)) {
3293 		btrfs_err(fs_info,
3294 "cannot replay dirty log with unsupported compat_ro features (0x%llx), try rescue=nologreplay",
3295 			  compat_ro);
3296 		return -EINVAL;
3297 	}
3298 
3299 	/*
3300 	 * Artificial limitations for block group tree, to force
3301 	 * block-group-tree to rely on no-holes and free-space-tree.
3302 	 */
3303 	if (btrfs_fs_compat_ro(fs_info, BLOCK_GROUP_TREE) &&
3304 	    (!btrfs_fs_incompat(fs_info, NO_HOLES) ||
3305 	     !btrfs_test_opt(fs_info, FREE_SPACE_TREE))) {
3306 		btrfs_err(fs_info,
3307 "block-group-tree feature requires no-holes and free-space-tree features");
3308 		return -EINVAL;
3309 	}
3310 
3311 	/*
3312 	 * Subpage runtime limitation on v1 cache.
3313 	 *
3314 	 * V1 space cache still has some hard codeed PAGE_SIZE usage, while
3315 	 * we're already defaulting to v2 cache, no need to bother v1 as it's
3316 	 * going to be deprecated anyway.
3317 	 */
3318 	if (fs_info->sectorsize < PAGE_SIZE && btrfs_test_opt(fs_info, SPACE_CACHE)) {
3319 		btrfs_warn(fs_info,
3320 	"v1 space cache is not supported for page size %lu with sectorsize %u",
3321 			   PAGE_SIZE, fs_info->sectorsize);
3322 		return -EINVAL;
3323 	}
3324 
3325 	/* This can be called by remount, we need to protect the super block. */
3326 	spin_lock(&fs_info->super_lock);
3327 	btrfs_set_super_incompat_flags(disk_super, incompat);
3328 	spin_unlock(&fs_info->super_lock);
3329 
3330 	return 0;
3331 }
3332 
3333 int __cold open_ctree(struct super_block *sb, struct btrfs_fs_devices *fs_devices,
3334 		      char *options)
3335 {
3336 	u32 sectorsize;
3337 	u32 nodesize;
3338 	u32 stripesize;
3339 	u64 generation;
3340 	u64 features;
3341 	u16 csum_type;
3342 	struct btrfs_super_block *disk_super;
3343 	struct btrfs_fs_info *fs_info = btrfs_sb(sb);
3344 	struct btrfs_root *tree_root;
3345 	struct btrfs_root *chunk_root;
3346 	int ret;
3347 	int err = -EINVAL;
3348 	int level;
3349 
3350 	ret = init_mount_fs_info(fs_info, sb);
3351 	if (ret) {
3352 		err = ret;
3353 		goto fail;
3354 	}
3355 
3356 	/* These need to be init'ed before we start creating inodes and such. */
3357 	tree_root = btrfs_alloc_root(fs_info, BTRFS_ROOT_TREE_OBJECTID,
3358 				     GFP_KERNEL);
3359 	fs_info->tree_root = tree_root;
3360 	chunk_root = btrfs_alloc_root(fs_info, BTRFS_CHUNK_TREE_OBJECTID,
3361 				      GFP_KERNEL);
3362 	fs_info->chunk_root = chunk_root;
3363 	if (!tree_root || !chunk_root) {
3364 		err = -ENOMEM;
3365 		goto fail;
3366 	}
3367 
3368 	fs_info->btree_inode = new_inode(sb);
3369 	if (!fs_info->btree_inode) {
3370 		err = -ENOMEM;
3371 		goto fail;
3372 	}
3373 	mapping_set_gfp_mask(fs_info->btree_inode->i_mapping, GFP_NOFS);
3374 	btrfs_init_btree_inode(fs_info);
3375 
3376 	invalidate_bdev(fs_devices->latest_dev->bdev);
3377 
3378 	/*
3379 	 * Read super block and check the signature bytes only
3380 	 */
3381 	disk_super = btrfs_read_dev_super(fs_devices->latest_dev->bdev);
3382 	if (IS_ERR(disk_super)) {
3383 		err = PTR_ERR(disk_super);
3384 		goto fail_alloc;
3385 	}
3386 
3387 	/*
3388 	 * Verify the type first, if that or the checksum value are
3389 	 * corrupted, we'll find out
3390 	 */
3391 	csum_type = btrfs_super_csum_type(disk_super);
3392 	if (!btrfs_supported_super_csum(csum_type)) {
3393 		btrfs_err(fs_info, "unsupported checksum algorithm: %u",
3394 			  csum_type);
3395 		err = -EINVAL;
3396 		btrfs_release_disk_super(disk_super);
3397 		goto fail_alloc;
3398 	}
3399 
3400 	fs_info->csum_size = btrfs_super_csum_size(disk_super);
3401 
3402 	ret = btrfs_init_csum_hash(fs_info, csum_type);
3403 	if (ret) {
3404 		err = ret;
3405 		btrfs_release_disk_super(disk_super);
3406 		goto fail_alloc;
3407 	}
3408 
3409 	/*
3410 	 * We want to check superblock checksum, the type is stored inside.
3411 	 * Pass the whole disk block of size BTRFS_SUPER_INFO_SIZE (4k).
3412 	 */
3413 	if (btrfs_check_super_csum(fs_info, disk_super)) {
3414 		btrfs_err(fs_info, "superblock checksum mismatch");
3415 		err = -EINVAL;
3416 		btrfs_release_disk_super(disk_super);
3417 		goto fail_alloc;
3418 	}
3419 
3420 	/*
3421 	 * super_copy is zeroed at allocation time and we never touch the
3422 	 * following bytes up to INFO_SIZE, the checksum is calculated from
3423 	 * the whole block of INFO_SIZE
3424 	 */
3425 	memcpy(fs_info->super_copy, disk_super, sizeof(*fs_info->super_copy));
3426 	btrfs_release_disk_super(disk_super);
3427 
3428 	disk_super = fs_info->super_copy;
3429 
3430 
3431 	features = btrfs_super_flags(disk_super);
3432 	if (features & BTRFS_SUPER_FLAG_CHANGING_FSID_V2) {
3433 		features &= ~BTRFS_SUPER_FLAG_CHANGING_FSID_V2;
3434 		btrfs_set_super_flags(disk_super, features);
3435 		btrfs_info(fs_info,
3436 			"found metadata UUID change in progress flag, clearing");
3437 	}
3438 
3439 	memcpy(fs_info->super_for_commit, fs_info->super_copy,
3440 	       sizeof(*fs_info->super_for_commit));
3441 
3442 	ret = btrfs_validate_mount_super(fs_info);
3443 	if (ret) {
3444 		btrfs_err(fs_info, "superblock contains fatal errors");
3445 		err = -EINVAL;
3446 		goto fail_alloc;
3447 	}
3448 
3449 	if (!btrfs_super_root(disk_super))
3450 		goto fail_alloc;
3451 
3452 	/* check FS state, whether FS is broken. */
3453 	if (btrfs_super_flags(disk_super) & BTRFS_SUPER_FLAG_ERROR)
3454 		set_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state);
3455 
3456 	/*
3457 	 * In the long term, we'll store the compression type in the super
3458 	 * block, and it'll be used for per file compression control.
3459 	 */
3460 	fs_info->compress_type = BTRFS_COMPRESS_ZLIB;
3461 
3462 
3463 	/* Set up fs_info before parsing mount options */
3464 	nodesize = btrfs_super_nodesize(disk_super);
3465 	sectorsize = btrfs_super_sectorsize(disk_super);
3466 	stripesize = sectorsize;
3467 	fs_info->dirty_metadata_batch = nodesize * (1 + ilog2(nr_cpu_ids));
3468 	fs_info->delalloc_batch = sectorsize * 512 * (1 + ilog2(nr_cpu_ids));
3469 
3470 	fs_info->nodesize = nodesize;
3471 	fs_info->sectorsize = sectorsize;
3472 	fs_info->sectorsize_bits = ilog2(sectorsize);
3473 	fs_info->csums_per_leaf = BTRFS_MAX_ITEM_SIZE(fs_info) / fs_info->csum_size;
3474 	fs_info->stripesize = stripesize;
3475 
3476 	ret = btrfs_parse_options(fs_info, options, sb->s_flags);
3477 	if (ret) {
3478 		err = ret;
3479 		goto fail_alloc;
3480 	}
3481 
3482 	ret = btrfs_check_features(fs_info, !sb_rdonly(sb));
3483 	if (ret < 0) {
3484 		err = ret;
3485 		goto fail_alloc;
3486 	}
3487 
3488 	if (sectorsize < PAGE_SIZE) {
3489 		struct btrfs_subpage_info *subpage_info;
3490 
3491 		/*
3492 		 * V1 space cache has some hardcoded PAGE_SIZE usage, and is
3493 		 * going to be deprecated.
3494 		 *
3495 		 * Force to use v2 cache for subpage case.
3496 		 */
3497 		btrfs_clear_opt(fs_info->mount_opt, SPACE_CACHE);
3498 		btrfs_set_and_info(fs_info, FREE_SPACE_TREE,
3499 			"forcing free space tree for sector size %u with page size %lu",
3500 			sectorsize, PAGE_SIZE);
3501 
3502 		btrfs_warn(fs_info,
3503 		"read-write for sector size %u with page size %lu is experimental",
3504 			   sectorsize, PAGE_SIZE);
3505 		subpage_info = kzalloc(sizeof(*subpage_info), GFP_KERNEL);
3506 		if (!subpage_info)
3507 			goto fail_alloc;
3508 		btrfs_init_subpage_info(subpage_info, sectorsize);
3509 		fs_info->subpage_info = subpage_info;
3510 	}
3511 
3512 	ret = btrfs_init_workqueues(fs_info);
3513 	if (ret) {
3514 		err = ret;
3515 		goto fail_sb_buffer;
3516 	}
3517 
3518 	sb->s_bdi->ra_pages *= btrfs_super_num_devices(disk_super);
3519 	sb->s_bdi->ra_pages = max(sb->s_bdi->ra_pages, SZ_4M / PAGE_SIZE);
3520 
3521 	sb->s_blocksize = sectorsize;
3522 	sb->s_blocksize_bits = blksize_bits(sectorsize);
3523 	memcpy(&sb->s_uuid, fs_info->fs_devices->fsid, BTRFS_FSID_SIZE);
3524 
3525 	mutex_lock(&fs_info->chunk_mutex);
3526 	ret = btrfs_read_sys_array(fs_info);
3527 	mutex_unlock(&fs_info->chunk_mutex);
3528 	if (ret) {
3529 		btrfs_err(fs_info, "failed to read the system array: %d", ret);
3530 		goto fail_sb_buffer;
3531 	}
3532 
3533 	generation = btrfs_super_chunk_root_generation(disk_super);
3534 	level = btrfs_super_chunk_root_level(disk_super);
3535 	ret = load_super_root(chunk_root, btrfs_super_chunk_root(disk_super),
3536 			      generation, level);
3537 	if (ret) {
3538 		btrfs_err(fs_info, "failed to read chunk root");
3539 		goto fail_tree_roots;
3540 	}
3541 
3542 	read_extent_buffer(chunk_root->node, fs_info->chunk_tree_uuid,
3543 			   offsetof(struct btrfs_header, chunk_tree_uuid),
3544 			   BTRFS_UUID_SIZE);
3545 
3546 	ret = btrfs_read_chunk_tree(fs_info);
3547 	if (ret) {
3548 		btrfs_err(fs_info, "failed to read chunk tree: %d", ret);
3549 		goto fail_tree_roots;
3550 	}
3551 
3552 	/*
3553 	 * At this point we know all the devices that make this filesystem,
3554 	 * including the seed devices but we don't know yet if the replace
3555 	 * target is required. So free devices that are not part of this
3556 	 * filesystem but skip the replace target device which is checked
3557 	 * below in btrfs_init_dev_replace().
3558 	 */
3559 	btrfs_free_extra_devids(fs_devices);
3560 	if (!fs_devices->latest_dev->bdev) {
3561 		btrfs_err(fs_info, "failed to read devices");
3562 		goto fail_tree_roots;
3563 	}
3564 
3565 	ret = init_tree_roots(fs_info);
3566 	if (ret)
3567 		goto fail_tree_roots;
3568 
3569 	/*
3570 	 * Get zone type information of zoned block devices. This will also
3571 	 * handle emulation of a zoned filesystem if a regular device has the
3572 	 * zoned incompat feature flag set.
3573 	 */
3574 	ret = btrfs_get_dev_zone_info_all_devices(fs_info);
3575 	if (ret) {
3576 		btrfs_err(fs_info,
3577 			  "zoned: failed to read device zone info: %d",
3578 			  ret);
3579 		goto fail_block_groups;
3580 	}
3581 
3582 	/*
3583 	 * If we have a uuid root and we're not being told to rescan we need to
3584 	 * check the generation here so we can set the
3585 	 * BTRFS_FS_UPDATE_UUID_TREE_GEN bit.  Otherwise we could commit the
3586 	 * transaction during a balance or the log replay without updating the
3587 	 * uuid generation, and then if we crash we would rescan the uuid tree,
3588 	 * even though it was perfectly fine.
3589 	 */
3590 	if (fs_info->uuid_root && !btrfs_test_opt(fs_info, RESCAN_UUID_TREE) &&
3591 	    fs_info->generation == btrfs_super_uuid_tree_generation(disk_super))
3592 		set_bit(BTRFS_FS_UPDATE_UUID_TREE_GEN, &fs_info->flags);
3593 
3594 	ret = btrfs_verify_dev_extents(fs_info);
3595 	if (ret) {
3596 		btrfs_err(fs_info,
3597 			  "failed to verify dev extents against chunks: %d",
3598 			  ret);
3599 		goto fail_block_groups;
3600 	}
3601 	ret = btrfs_recover_balance(fs_info);
3602 	if (ret) {
3603 		btrfs_err(fs_info, "failed to recover balance: %d", ret);
3604 		goto fail_block_groups;
3605 	}
3606 
3607 	ret = btrfs_init_dev_stats(fs_info);
3608 	if (ret) {
3609 		btrfs_err(fs_info, "failed to init dev_stats: %d", ret);
3610 		goto fail_block_groups;
3611 	}
3612 
3613 	ret = btrfs_init_dev_replace(fs_info);
3614 	if (ret) {
3615 		btrfs_err(fs_info, "failed to init dev_replace: %d", ret);
3616 		goto fail_block_groups;
3617 	}
3618 
3619 	ret = btrfs_check_zoned_mode(fs_info);
3620 	if (ret) {
3621 		btrfs_err(fs_info, "failed to initialize zoned mode: %d",
3622 			  ret);
3623 		goto fail_block_groups;
3624 	}
3625 
3626 	ret = btrfs_sysfs_add_fsid(fs_devices);
3627 	if (ret) {
3628 		btrfs_err(fs_info, "failed to init sysfs fsid interface: %d",
3629 				ret);
3630 		goto fail_block_groups;
3631 	}
3632 
3633 	ret = btrfs_sysfs_add_mounted(fs_info);
3634 	if (ret) {
3635 		btrfs_err(fs_info, "failed to init sysfs interface: %d", ret);
3636 		goto fail_fsdev_sysfs;
3637 	}
3638 
3639 	ret = btrfs_init_space_info(fs_info);
3640 	if (ret) {
3641 		btrfs_err(fs_info, "failed to initialize space info: %d", ret);
3642 		goto fail_sysfs;
3643 	}
3644 
3645 	ret = btrfs_read_block_groups(fs_info);
3646 	if (ret) {
3647 		btrfs_err(fs_info, "failed to read block groups: %d", ret);
3648 		goto fail_sysfs;
3649 	}
3650 
3651 	btrfs_free_zone_cache(fs_info);
3652 
3653 	if (!sb_rdonly(sb) && fs_info->fs_devices->missing_devices &&
3654 	    !btrfs_check_rw_degradable(fs_info, NULL)) {
3655 		btrfs_warn(fs_info,
3656 		"writable mount is not allowed due to too many missing devices");
3657 		goto fail_sysfs;
3658 	}
3659 
3660 	fs_info->cleaner_kthread = kthread_run(cleaner_kthread, fs_info,
3661 					       "btrfs-cleaner");
3662 	if (IS_ERR(fs_info->cleaner_kthread))
3663 		goto fail_sysfs;
3664 
3665 	fs_info->transaction_kthread = kthread_run(transaction_kthread,
3666 						   tree_root,
3667 						   "btrfs-transaction");
3668 	if (IS_ERR(fs_info->transaction_kthread))
3669 		goto fail_cleaner;
3670 
3671 	if (!btrfs_test_opt(fs_info, NOSSD) &&
3672 	    !fs_info->fs_devices->rotating) {
3673 		btrfs_set_and_info(fs_info, SSD, "enabling ssd optimizations");
3674 	}
3675 
3676 	/*
3677 	 * For devices supporting discard turn on discard=async automatically,
3678 	 * unless it's already set or disabled. This could be turned off by
3679 	 * nodiscard for the same mount.
3680 	 */
3681 	if (!(btrfs_test_opt(fs_info, DISCARD_SYNC) ||
3682 	      btrfs_test_opt(fs_info, DISCARD_ASYNC) ||
3683 	      btrfs_test_opt(fs_info, NODISCARD)) &&
3684 	    fs_info->fs_devices->discardable) {
3685 		btrfs_set_and_info(fs_info, DISCARD_ASYNC,
3686 				   "auto enabling async discard");
3687 		btrfs_clear_opt(fs_info->mount_opt, NODISCARD);
3688 	}
3689 
3690 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
3691 	if (btrfs_test_opt(fs_info, CHECK_INTEGRITY)) {
3692 		ret = btrfsic_mount(fs_info, fs_devices,
3693 				    btrfs_test_opt(fs_info,
3694 					CHECK_INTEGRITY_DATA) ? 1 : 0,
3695 				    fs_info->check_integrity_print_mask);
3696 		if (ret)
3697 			btrfs_warn(fs_info,
3698 				"failed to initialize integrity check module: %d",
3699 				ret);
3700 	}
3701 #endif
3702 	ret = btrfs_read_qgroup_config(fs_info);
3703 	if (ret)
3704 		goto fail_trans_kthread;
3705 
3706 	if (btrfs_build_ref_tree(fs_info))
3707 		btrfs_err(fs_info, "couldn't build ref tree");
3708 
3709 	/* do not make disk changes in broken FS or nologreplay is given */
3710 	if (btrfs_super_log_root(disk_super) != 0 &&
3711 	    !btrfs_test_opt(fs_info, NOLOGREPLAY)) {
3712 		btrfs_info(fs_info, "start tree-log replay");
3713 		ret = btrfs_replay_log(fs_info, fs_devices);
3714 		if (ret) {
3715 			err = ret;
3716 			goto fail_qgroup;
3717 		}
3718 	}
3719 
3720 	fs_info->fs_root = btrfs_get_fs_root(fs_info, BTRFS_FS_TREE_OBJECTID, true);
3721 	if (IS_ERR(fs_info->fs_root)) {
3722 		err = PTR_ERR(fs_info->fs_root);
3723 		btrfs_warn(fs_info, "failed to read fs tree: %d", err);
3724 		fs_info->fs_root = NULL;
3725 		goto fail_qgroup;
3726 	}
3727 
3728 	if (sb_rdonly(sb))
3729 		goto clear_oneshot;
3730 
3731 	ret = btrfs_start_pre_rw_mount(fs_info);
3732 	if (ret) {
3733 		close_ctree(fs_info);
3734 		return ret;
3735 	}
3736 	btrfs_discard_resume(fs_info);
3737 
3738 	if (fs_info->uuid_root &&
3739 	    (btrfs_test_opt(fs_info, RESCAN_UUID_TREE) ||
3740 	     fs_info->generation != btrfs_super_uuid_tree_generation(disk_super))) {
3741 		btrfs_info(fs_info, "checking UUID tree");
3742 		ret = btrfs_check_uuid_tree(fs_info);
3743 		if (ret) {
3744 			btrfs_warn(fs_info,
3745 				"failed to check the UUID tree: %d", ret);
3746 			close_ctree(fs_info);
3747 			return ret;
3748 		}
3749 	}
3750 
3751 	set_bit(BTRFS_FS_OPEN, &fs_info->flags);
3752 
3753 	/* Kick the cleaner thread so it'll start deleting snapshots. */
3754 	if (test_bit(BTRFS_FS_UNFINISHED_DROPS, &fs_info->flags))
3755 		wake_up_process(fs_info->cleaner_kthread);
3756 
3757 clear_oneshot:
3758 	btrfs_clear_oneshot_options(fs_info);
3759 	return 0;
3760 
3761 fail_qgroup:
3762 	btrfs_free_qgroup_config(fs_info);
3763 fail_trans_kthread:
3764 	kthread_stop(fs_info->transaction_kthread);
3765 	btrfs_cleanup_transaction(fs_info);
3766 	btrfs_free_fs_roots(fs_info);
3767 fail_cleaner:
3768 	kthread_stop(fs_info->cleaner_kthread);
3769 
3770 	/*
3771 	 * make sure we're done with the btree inode before we stop our
3772 	 * kthreads
3773 	 */
3774 	filemap_write_and_wait(fs_info->btree_inode->i_mapping);
3775 
3776 fail_sysfs:
3777 	btrfs_sysfs_remove_mounted(fs_info);
3778 
3779 fail_fsdev_sysfs:
3780 	btrfs_sysfs_remove_fsid(fs_info->fs_devices);
3781 
3782 fail_block_groups:
3783 	btrfs_put_block_group_cache(fs_info);
3784 
3785 fail_tree_roots:
3786 	if (fs_info->data_reloc_root)
3787 		btrfs_drop_and_free_fs_root(fs_info, fs_info->data_reloc_root);
3788 	free_root_pointers(fs_info, true);
3789 	invalidate_inode_pages2(fs_info->btree_inode->i_mapping);
3790 
3791 fail_sb_buffer:
3792 	btrfs_stop_all_workers(fs_info);
3793 	btrfs_free_block_groups(fs_info);
3794 fail_alloc:
3795 	btrfs_mapping_tree_free(&fs_info->mapping_tree);
3796 
3797 	iput(fs_info->btree_inode);
3798 fail:
3799 	btrfs_close_devices(fs_info->fs_devices);
3800 	return err;
3801 }
3802 ALLOW_ERROR_INJECTION(open_ctree, ERRNO);
3803 
3804 static void btrfs_end_super_write(struct bio *bio)
3805 {
3806 	struct btrfs_device *device = bio->bi_private;
3807 	struct bio_vec *bvec;
3808 	struct bvec_iter_all iter_all;
3809 	struct page *page;
3810 
3811 	bio_for_each_segment_all(bvec, bio, iter_all) {
3812 		page = bvec->bv_page;
3813 
3814 		if (bio->bi_status) {
3815 			btrfs_warn_rl_in_rcu(device->fs_info,
3816 				"lost page write due to IO error on %s (%d)",
3817 				btrfs_dev_name(device),
3818 				blk_status_to_errno(bio->bi_status));
3819 			ClearPageUptodate(page);
3820 			SetPageError(page);
3821 			btrfs_dev_stat_inc_and_print(device,
3822 						     BTRFS_DEV_STAT_WRITE_ERRS);
3823 		} else {
3824 			SetPageUptodate(page);
3825 		}
3826 
3827 		put_page(page);
3828 		unlock_page(page);
3829 	}
3830 
3831 	bio_put(bio);
3832 }
3833 
3834 struct btrfs_super_block *btrfs_read_dev_one_super(struct block_device *bdev,
3835 						   int copy_num, bool drop_cache)
3836 {
3837 	struct btrfs_super_block *super;
3838 	struct page *page;
3839 	u64 bytenr, bytenr_orig;
3840 	struct address_space *mapping = bdev->bd_inode->i_mapping;
3841 	int ret;
3842 
3843 	bytenr_orig = btrfs_sb_offset(copy_num);
3844 	ret = btrfs_sb_log_location_bdev(bdev, copy_num, READ, &bytenr);
3845 	if (ret == -ENOENT)
3846 		return ERR_PTR(-EINVAL);
3847 	else if (ret)
3848 		return ERR_PTR(ret);
3849 
3850 	if (bytenr + BTRFS_SUPER_INFO_SIZE >= bdev_nr_bytes(bdev))
3851 		return ERR_PTR(-EINVAL);
3852 
3853 	if (drop_cache) {
3854 		/* This should only be called with the primary sb. */
3855 		ASSERT(copy_num == 0);
3856 
3857 		/*
3858 		 * Drop the page of the primary superblock, so later read will
3859 		 * always read from the device.
3860 		 */
3861 		invalidate_inode_pages2_range(mapping,
3862 				bytenr >> PAGE_SHIFT,
3863 				(bytenr + BTRFS_SUPER_INFO_SIZE) >> PAGE_SHIFT);
3864 	}
3865 
3866 	page = read_cache_page_gfp(mapping, bytenr >> PAGE_SHIFT, GFP_NOFS);
3867 	if (IS_ERR(page))
3868 		return ERR_CAST(page);
3869 
3870 	super = page_address(page);
3871 	if (btrfs_super_magic(super) != BTRFS_MAGIC) {
3872 		btrfs_release_disk_super(super);
3873 		return ERR_PTR(-ENODATA);
3874 	}
3875 
3876 	if (btrfs_super_bytenr(super) != bytenr_orig) {
3877 		btrfs_release_disk_super(super);
3878 		return ERR_PTR(-EINVAL);
3879 	}
3880 
3881 	return super;
3882 }
3883 
3884 
3885 struct btrfs_super_block *btrfs_read_dev_super(struct block_device *bdev)
3886 {
3887 	struct btrfs_super_block *super, *latest = NULL;
3888 	int i;
3889 	u64 transid = 0;
3890 
3891 	/* we would like to check all the supers, but that would make
3892 	 * a btrfs mount succeed after a mkfs from a different FS.
3893 	 * So, we need to add a special mount option to scan for
3894 	 * later supers, using BTRFS_SUPER_MIRROR_MAX instead
3895 	 */
3896 	for (i = 0; i < 1; i++) {
3897 		super = btrfs_read_dev_one_super(bdev, i, false);
3898 		if (IS_ERR(super))
3899 			continue;
3900 
3901 		if (!latest || btrfs_super_generation(super) > transid) {
3902 			if (latest)
3903 				btrfs_release_disk_super(super);
3904 
3905 			latest = super;
3906 			transid = btrfs_super_generation(super);
3907 		}
3908 	}
3909 
3910 	return super;
3911 }
3912 
3913 /*
3914  * Write superblock @sb to the @device. Do not wait for completion, all the
3915  * pages we use for writing are locked.
3916  *
3917  * Write @max_mirrors copies of the superblock, where 0 means default that fit
3918  * the expected device size at commit time. Note that max_mirrors must be
3919  * same for write and wait phases.
3920  *
3921  * Return number of errors when page is not found or submission fails.
3922  */
3923 static int write_dev_supers(struct btrfs_device *device,
3924 			    struct btrfs_super_block *sb, int max_mirrors)
3925 {
3926 	struct btrfs_fs_info *fs_info = device->fs_info;
3927 	struct address_space *mapping = device->bdev->bd_inode->i_mapping;
3928 	SHASH_DESC_ON_STACK(shash, fs_info->csum_shash);
3929 	int i;
3930 	int errors = 0;
3931 	int ret;
3932 	u64 bytenr, bytenr_orig;
3933 
3934 	if (max_mirrors == 0)
3935 		max_mirrors = BTRFS_SUPER_MIRROR_MAX;
3936 
3937 	shash->tfm = fs_info->csum_shash;
3938 
3939 	for (i = 0; i < max_mirrors; i++) {
3940 		struct page *page;
3941 		struct bio *bio;
3942 		struct btrfs_super_block *disk_super;
3943 
3944 		bytenr_orig = btrfs_sb_offset(i);
3945 		ret = btrfs_sb_log_location(device, i, WRITE, &bytenr);
3946 		if (ret == -ENOENT) {
3947 			continue;
3948 		} else if (ret < 0) {
3949 			btrfs_err(device->fs_info,
3950 				"couldn't get super block location for mirror %d",
3951 				i);
3952 			errors++;
3953 			continue;
3954 		}
3955 		if (bytenr + BTRFS_SUPER_INFO_SIZE >=
3956 		    device->commit_total_bytes)
3957 			break;
3958 
3959 		btrfs_set_super_bytenr(sb, bytenr_orig);
3960 
3961 		crypto_shash_digest(shash, (const char *)sb + BTRFS_CSUM_SIZE,
3962 				    BTRFS_SUPER_INFO_SIZE - BTRFS_CSUM_SIZE,
3963 				    sb->csum);
3964 
3965 		page = find_or_create_page(mapping, bytenr >> PAGE_SHIFT,
3966 					   GFP_NOFS);
3967 		if (!page) {
3968 			btrfs_err(device->fs_info,
3969 			    "couldn't get super block page for bytenr %llu",
3970 			    bytenr);
3971 			errors++;
3972 			continue;
3973 		}
3974 
3975 		/* Bump the refcount for wait_dev_supers() */
3976 		get_page(page);
3977 
3978 		disk_super = page_address(page);
3979 		memcpy(disk_super, sb, BTRFS_SUPER_INFO_SIZE);
3980 
3981 		/*
3982 		 * Directly use bios here instead of relying on the page cache
3983 		 * to do I/O, so we don't lose the ability to do integrity
3984 		 * checking.
3985 		 */
3986 		bio = bio_alloc(device->bdev, 1,
3987 				REQ_OP_WRITE | REQ_SYNC | REQ_META | REQ_PRIO,
3988 				GFP_NOFS);
3989 		bio->bi_iter.bi_sector = bytenr >> SECTOR_SHIFT;
3990 		bio->bi_private = device;
3991 		bio->bi_end_io = btrfs_end_super_write;
3992 		__bio_add_page(bio, page, BTRFS_SUPER_INFO_SIZE,
3993 			       offset_in_page(bytenr));
3994 
3995 		/*
3996 		 * We FUA only the first super block.  The others we allow to
3997 		 * go down lazy and there's a short window where the on-disk
3998 		 * copies might still contain the older version.
3999 		 */
4000 		if (i == 0 && !btrfs_test_opt(device->fs_info, NOBARRIER))
4001 			bio->bi_opf |= REQ_FUA;
4002 
4003 		btrfsic_check_bio(bio);
4004 		submit_bio(bio);
4005 
4006 		if (btrfs_advance_sb_log(device, i))
4007 			errors++;
4008 	}
4009 	return errors < i ? 0 : -1;
4010 }
4011 
4012 /*
4013  * Wait for write completion of superblocks done by write_dev_supers,
4014  * @max_mirrors same for write and wait phases.
4015  *
4016  * Return number of errors when page is not found or not marked up to
4017  * date.
4018  */
4019 static int wait_dev_supers(struct btrfs_device *device, int max_mirrors)
4020 {
4021 	int i;
4022 	int errors = 0;
4023 	bool primary_failed = false;
4024 	int ret;
4025 	u64 bytenr;
4026 
4027 	if (max_mirrors == 0)
4028 		max_mirrors = BTRFS_SUPER_MIRROR_MAX;
4029 
4030 	for (i = 0; i < max_mirrors; i++) {
4031 		struct page *page;
4032 
4033 		ret = btrfs_sb_log_location(device, i, READ, &bytenr);
4034 		if (ret == -ENOENT) {
4035 			break;
4036 		} else if (ret < 0) {
4037 			errors++;
4038 			if (i == 0)
4039 				primary_failed = true;
4040 			continue;
4041 		}
4042 		if (bytenr + BTRFS_SUPER_INFO_SIZE >=
4043 		    device->commit_total_bytes)
4044 			break;
4045 
4046 		page = find_get_page(device->bdev->bd_inode->i_mapping,
4047 				     bytenr >> PAGE_SHIFT);
4048 		if (!page) {
4049 			errors++;
4050 			if (i == 0)
4051 				primary_failed = true;
4052 			continue;
4053 		}
4054 		/* Page is submitted locked and unlocked once the IO completes */
4055 		wait_on_page_locked(page);
4056 		if (PageError(page)) {
4057 			errors++;
4058 			if (i == 0)
4059 				primary_failed = true;
4060 		}
4061 
4062 		/* Drop our reference */
4063 		put_page(page);
4064 
4065 		/* Drop the reference from the writing run */
4066 		put_page(page);
4067 	}
4068 
4069 	/* log error, force error return */
4070 	if (primary_failed) {
4071 		btrfs_err(device->fs_info, "error writing primary super block to device %llu",
4072 			  device->devid);
4073 		return -1;
4074 	}
4075 
4076 	return errors < i ? 0 : -1;
4077 }
4078 
4079 /*
4080  * endio for the write_dev_flush, this will wake anyone waiting
4081  * for the barrier when it is done
4082  */
4083 static void btrfs_end_empty_barrier(struct bio *bio)
4084 {
4085 	bio_uninit(bio);
4086 	complete(bio->bi_private);
4087 }
4088 
4089 /*
4090  * Submit a flush request to the device if it supports it. Error handling is
4091  * done in the waiting counterpart.
4092  */
4093 static void write_dev_flush(struct btrfs_device *device)
4094 {
4095 	struct bio *bio = &device->flush_bio;
4096 
4097 #ifndef CONFIG_BTRFS_FS_CHECK_INTEGRITY
4098 	/*
4099 	 * When a disk has write caching disabled, we skip submission of a bio
4100 	 * with flush and sync requests before writing the superblock, since
4101 	 * it's not needed. However when the integrity checker is enabled, this
4102 	 * results in reports that there are metadata blocks referred by a
4103 	 * superblock that were not properly flushed. So don't skip the bio
4104 	 * submission only when the integrity checker is enabled for the sake
4105 	 * of simplicity, since this is a debug tool and not meant for use in
4106 	 * non-debug builds.
4107 	 */
4108 	if (!bdev_write_cache(device->bdev))
4109 		return;
4110 #endif
4111 
4112 	bio_init(bio, device->bdev, NULL, 0,
4113 		 REQ_OP_WRITE | REQ_SYNC | REQ_PREFLUSH);
4114 	bio->bi_end_io = btrfs_end_empty_barrier;
4115 	init_completion(&device->flush_wait);
4116 	bio->bi_private = &device->flush_wait;
4117 
4118 	btrfsic_check_bio(bio);
4119 	submit_bio(bio);
4120 	set_bit(BTRFS_DEV_STATE_FLUSH_SENT, &device->dev_state);
4121 }
4122 
4123 /*
4124  * If the flush bio has been submitted by write_dev_flush, wait for it.
4125  */
4126 static blk_status_t wait_dev_flush(struct btrfs_device *device)
4127 {
4128 	struct bio *bio = &device->flush_bio;
4129 
4130 	if (!test_bit(BTRFS_DEV_STATE_FLUSH_SENT, &device->dev_state))
4131 		return BLK_STS_OK;
4132 
4133 	clear_bit(BTRFS_DEV_STATE_FLUSH_SENT, &device->dev_state);
4134 	wait_for_completion_io(&device->flush_wait);
4135 
4136 	return bio->bi_status;
4137 }
4138 
4139 static int check_barrier_error(struct btrfs_fs_info *fs_info)
4140 {
4141 	if (!btrfs_check_rw_degradable(fs_info, NULL))
4142 		return -EIO;
4143 	return 0;
4144 }
4145 
4146 /*
4147  * send an empty flush down to each device in parallel,
4148  * then wait for them
4149  */
4150 static int barrier_all_devices(struct btrfs_fs_info *info)
4151 {
4152 	struct list_head *head;
4153 	struct btrfs_device *dev;
4154 	int errors_wait = 0;
4155 	blk_status_t ret;
4156 
4157 	lockdep_assert_held(&info->fs_devices->device_list_mutex);
4158 	/* send down all the barriers */
4159 	head = &info->fs_devices->devices;
4160 	list_for_each_entry(dev, head, dev_list) {
4161 		if (test_bit(BTRFS_DEV_STATE_MISSING, &dev->dev_state))
4162 			continue;
4163 		if (!dev->bdev)
4164 			continue;
4165 		if (!test_bit(BTRFS_DEV_STATE_IN_FS_METADATA, &dev->dev_state) ||
4166 		    !test_bit(BTRFS_DEV_STATE_WRITEABLE, &dev->dev_state))
4167 			continue;
4168 
4169 		write_dev_flush(dev);
4170 		dev->last_flush_error = BLK_STS_OK;
4171 	}
4172 
4173 	/* wait for all the barriers */
4174 	list_for_each_entry(dev, head, dev_list) {
4175 		if (test_bit(BTRFS_DEV_STATE_MISSING, &dev->dev_state))
4176 			continue;
4177 		if (!dev->bdev) {
4178 			errors_wait++;
4179 			continue;
4180 		}
4181 		if (!test_bit(BTRFS_DEV_STATE_IN_FS_METADATA, &dev->dev_state) ||
4182 		    !test_bit(BTRFS_DEV_STATE_WRITEABLE, &dev->dev_state))
4183 			continue;
4184 
4185 		ret = wait_dev_flush(dev);
4186 		if (ret) {
4187 			dev->last_flush_error = ret;
4188 			btrfs_dev_stat_inc_and_print(dev,
4189 					BTRFS_DEV_STAT_FLUSH_ERRS);
4190 			errors_wait++;
4191 		}
4192 	}
4193 
4194 	if (errors_wait) {
4195 		/*
4196 		 * At some point we need the status of all disks
4197 		 * to arrive at the volume status. So error checking
4198 		 * is being pushed to a separate loop.
4199 		 */
4200 		return check_barrier_error(info);
4201 	}
4202 	return 0;
4203 }
4204 
4205 int btrfs_get_num_tolerated_disk_barrier_failures(u64 flags)
4206 {
4207 	int raid_type;
4208 	int min_tolerated = INT_MAX;
4209 
4210 	if ((flags & BTRFS_BLOCK_GROUP_PROFILE_MASK) == 0 ||
4211 	    (flags & BTRFS_AVAIL_ALLOC_BIT_SINGLE))
4212 		min_tolerated = min_t(int, min_tolerated,
4213 				    btrfs_raid_array[BTRFS_RAID_SINGLE].
4214 				    tolerated_failures);
4215 
4216 	for (raid_type = 0; raid_type < BTRFS_NR_RAID_TYPES; raid_type++) {
4217 		if (raid_type == BTRFS_RAID_SINGLE)
4218 			continue;
4219 		if (!(flags & btrfs_raid_array[raid_type].bg_flag))
4220 			continue;
4221 		min_tolerated = min_t(int, min_tolerated,
4222 				    btrfs_raid_array[raid_type].
4223 				    tolerated_failures);
4224 	}
4225 
4226 	if (min_tolerated == INT_MAX) {
4227 		pr_warn("BTRFS: unknown raid flag: %llu", flags);
4228 		min_tolerated = 0;
4229 	}
4230 
4231 	return min_tolerated;
4232 }
4233 
4234 int write_all_supers(struct btrfs_fs_info *fs_info, int max_mirrors)
4235 {
4236 	struct list_head *head;
4237 	struct btrfs_device *dev;
4238 	struct btrfs_super_block *sb;
4239 	struct btrfs_dev_item *dev_item;
4240 	int ret;
4241 	int do_barriers;
4242 	int max_errors;
4243 	int total_errors = 0;
4244 	u64 flags;
4245 
4246 	do_barriers = !btrfs_test_opt(fs_info, NOBARRIER);
4247 
4248 	/*
4249 	 * max_mirrors == 0 indicates we're from commit_transaction,
4250 	 * not from fsync where the tree roots in fs_info have not
4251 	 * been consistent on disk.
4252 	 */
4253 	if (max_mirrors == 0)
4254 		backup_super_roots(fs_info);
4255 
4256 	sb = fs_info->super_for_commit;
4257 	dev_item = &sb->dev_item;
4258 
4259 	mutex_lock(&fs_info->fs_devices->device_list_mutex);
4260 	head = &fs_info->fs_devices->devices;
4261 	max_errors = btrfs_super_num_devices(fs_info->super_copy) - 1;
4262 
4263 	if (do_barriers) {
4264 		ret = barrier_all_devices(fs_info);
4265 		if (ret) {
4266 			mutex_unlock(
4267 				&fs_info->fs_devices->device_list_mutex);
4268 			btrfs_handle_fs_error(fs_info, ret,
4269 					      "errors while submitting device barriers.");
4270 			return ret;
4271 		}
4272 	}
4273 
4274 	list_for_each_entry(dev, head, dev_list) {
4275 		if (!dev->bdev) {
4276 			total_errors++;
4277 			continue;
4278 		}
4279 		if (!test_bit(BTRFS_DEV_STATE_IN_FS_METADATA, &dev->dev_state) ||
4280 		    !test_bit(BTRFS_DEV_STATE_WRITEABLE, &dev->dev_state))
4281 			continue;
4282 
4283 		btrfs_set_stack_device_generation(dev_item, 0);
4284 		btrfs_set_stack_device_type(dev_item, dev->type);
4285 		btrfs_set_stack_device_id(dev_item, dev->devid);
4286 		btrfs_set_stack_device_total_bytes(dev_item,
4287 						   dev->commit_total_bytes);
4288 		btrfs_set_stack_device_bytes_used(dev_item,
4289 						  dev->commit_bytes_used);
4290 		btrfs_set_stack_device_io_align(dev_item, dev->io_align);
4291 		btrfs_set_stack_device_io_width(dev_item, dev->io_width);
4292 		btrfs_set_stack_device_sector_size(dev_item, dev->sector_size);
4293 		memcpy(dev_item->uuid, dev->uuid, BTRFS_UUID_SIZE);
4294 		memcpy(dev_item->fsid, dev->fs_devices->metadata_uuid,
4295 		       BTRFS_FSID_SIZE);
4296 
4297 		flags = btrfs_super_flags(sb);
4298 		btrfs_set_super_flags(sb, flags | BTRFS_HEADER_FLAG_WRITTEN);
4299 
4300 		ret = btrfs_validate_write_super(fs_info, sb);
4301 		if (ret < 0) {
4302 			mutex_unlock(&fs_info->fs_devices->device_list_mutex);
4303 			btrfs_handle_fs_error(fs_info, -EUCLEAN,
4304 				"unexpected superblock corruption detected");
4305 			return -EUCLEAN;
4306 		}
4307 
4308 		ret = write_dev_supers(dev, sb, max_mirrors);
4309 		if (ret)
4310 			total_errors++;
4311 	}
4312 	if (total_errors > max_errors) {
4313 		btrfs_err(fs_info, "%d errors while writing supers",
4314 			  total_errors);
4315 		mutex_unlock(&fs_info->fs_devices->device_list_mutex);
4316 
4317 		/* FUA is masked off if unsupported and can't be the reason */
4318 		btrfs_handle_fs_error(fs_info, -EIO,
4319 				      "%d errors while writing supers",
4320 				      total_errors);
4321 		return -EIO;
4322 	}
4323 
4324 	total_errors = 0;
4325 	list_for_each_entry(dev, head, dev_list) {
4326 		if (!dev->bdev)
4327 			continue;
4328 		if (!test_bit(BTRFS_DEV_STATE_IN_FS_METADATA, &dev->dev_state) ||
4329 		    !test_bit(BTRFS_DEV_STATE_WRITEABLE, &dev->dev_state))
4330 			continue;
4331 
4332 		ret = wait_dev_supers(dev, max_mirrors);
4333 		if (ret)
4334 			total_errors++;
4335 	}
4336 	mutex_unlock(&fs_info->fs_devices->device_list_mutex);
4337 	if (total_errors > max_errors) {
4338 		btrfs_handle_fs_error(fs_info, -EIO,
4339 				      "%d errors while writing supers",
4340 				      total_errors);
4341 		return -EIO;
4342 	}
4343 	return 0;
4344 }
4345 
4346 /* Drop a fs root from the radix tree and free it. */
4347 void btrfs_drop_and_free_fs_root(struct btrfs_fs_info *fs_info,
4348 				  struct btrfs_root *root)
4349 {
4350 	bool drop_ref = false;
4351 
4352 	spin_lock(&fs_info->fs_roots_radix_lock);
4353 	radix_tree_delete(&fs_info->fs_roots_radix,
4354 			  (unsigned long)root->root_key.objectid);
4355 	if (test_and_clear_bit(BTRFS_ROOT_IN_RADIX, &root->state))
4356 		drop_ref = true;
4357 	spin_unlock(&fs_info->fs_roots_radix_lock);
4358 
4359 	if (BTRFS_FS_ERROR(fs_info)) {
4360 		ASSERT(root->log_root == NULL);
4361 		if (root->reloc_root) {
4362 			btrfs_put_root(root->reloc_root);
4363 			root->reloc_root = NULL;
4364 		}
4365 	}
4366 
4367 	if (drop_ref)
4368 		btrfs_put_root(root);
4369 }
4370 
4371 int btrfs_cleanup_fs_roots(struct btrfs_fs_info *fs_info)
4372 {
4373 	u64 root_objectid = 0;
4374 	struct btrfs_root *gang[8];
4375 	int i = 0;
4376 	int err = 0;
4377 	unsigned int ret = 0;
4378 
4379 	while (1) {
4380 		spin_lock(&fs_info->fs_roots_radix_lock);
4381 		ret = radix_tree_gang_lookup(&fs_info->fs_roots_radix,
4382 					     (void **)gang, root_objectid,
4383 					     ARRAY_SIZE(gang));
4384 		if (!ret) {
4385 			spin_unlock(&fs_info->fs_roots_radix_lock);
4386 			break;
4387 		}
4388 		root_objectid = gang[ret - 1]->root_key.objectid + 1;
4389 
4390 		for (i = 0; i < ret; i++) {
4391 			/* Avoid to grab roots in dead_roots */
4392 			if (btrfs_root_refs(&gang[i]->root_item) == 0) {
4393 				gang[i] = NULL;
4394 				continue;
4395 			}
4396 			/* grab all the search result for later use */
4397 			gang[i] = btrfs_grab_root(gang[i]);
4398 		}
4399 		spin_unlock(&fs_info->fs_roots_radix_lock);
4400 
4401 		for (i = 0; i < ret; i++) {
4402 			if (!gang[i])
4403 				continue;
4404 			root_objectid = gang[i]->root_key.objectid;
4405 			err = btrfs_orphan_cleanup(gang[i]);
4406 			if (err)
4407 				break;
4408 			btrfs_put_root(gang[i]);
4409 		}
4410 		root_objectid++;
4411 	}
4412 
4413 	/* release the uncleaned roots due to error */
4414 	for (; i < ret; i++) {
4415 		if (gang[i])
4416 			btrfs_put_root(gang[i]);
4417 	}
4418 	return err;
4419 }
4420 
4421 int btrfs_commit_super(struct btrfs_fs_info *fs_info)
4422 {
4423 	struct btrfs_root *root = fs_info->tree_root;
4424 	struct btrfs_trans_handle *trans;
4425 
4426 	mutex_lock(&fs_info->cleaner_mutex);
4427 	btrfs_run_delayed_iputs(fs_info);
4428 	mutex_unlock(&fs_info->cleaner_mutex);
4429 	wake_up_process(fs_info->cleaner_kthread);
4430 
4431 	/* wait until ongoing cleanup work done */
4432 	down_write(&fs_info->cleanup_work_sem);
4433 	up_write(&fs_info->cleanup_work_sem);
4434 
4435 	trans = btrfs_join_transaction(root);
4436 	if (IS_ERR(trans))
4437 		return PTR_ERR(trans);
4438 	return btrfs_commit_transaction(trans);
4439 }
4440 
4441 static void warn_about_uncommitted_trans(struct btrfs_fs_info *fs_info)
4442 {
4443 	struct btrfs_transaction *trans;
4444 	struct btrfs_transaction *tmp;
4445 	bool found = false;
4446 
4447 	if (list_empty(&fs_info->trans_list))
4448 		return;
4449 
4450 	/*
4451 	 * This function is only called at the very end of close_ctree(),
4452 	 * thus no other running transaction, no need to take trans_lock.
4453 	 */
4454 	ASSERT(test_bit(BTRFS_FS_CLOSING_DONE, &fs_info->flags));
4455 	list_for_each_entry_safe(trans, tmp, &fs_info->trans_list, list) {
4456 		struct extent_state *cached = NULL;
4457 		u64 dirty_bytes = 0;
4458 		u64 cur = 0;
4459 		u64 found_start;
4460 		u64 found_end;
4461 
4462 		found = true;
4463 		while (!find_first_extent_bit(&trans->dirty_pages, cur,
4464 			&found_start, &found_end, EXTENT_DIRTY, &cached)) {
4465 			dirty_bytes += found_end + 1 - found_start;
4466 			cur = found_end + 1;
4467 		}
4468 		btrfs_warn(fs_info,
4469 	"transaction %llu (with %llu dirty metadata bytes) is not committed",
4470 			   trans->transid, dirty_bytes);
4471 		btrfs_cleanup_one_transaction(trans, fs_info);
4472 
4473 		if (trans == fs_info->running_transaction)
4474 			fs_info->running_transaction = NULL;
4475 		list_del_init(&trans->list);
4476 
4477 		btrfs_put_transaction(trans);
4478 		trace_btrfs_transaction_commit(fs_info);
4479 	}
4480 	ASSERT(!found);
4481 }
4482 
4483 void __cold close_ctree(struct btrfs_fs_info *fs_info)
4484 {
4485 	int ret;
4486 
4487 	set_bit(BTRFS_FS_CLOSING_START, &fs_info->flags);
4488 
4489 	/*
4490 	 * If we had UNFINISHED_DROPS we could still be processing them, so
4491 	 * clear that bit and wake up relocation so it can stop.
4492 	 * We must do this before stopping the block group reclaim task, because
4493 	 * at btrfs_relocate_block_group() we wait for this bit, and after the
4494 	 * wait we stop with -EINTR if btrfs_fs_closing() returns non-zero - we
4495 	 * have just set BTRFS_FS_CLOSING_START, so btrfs_fs_closing() will
4496 	 * return 1.
4497 	 */
4498 	btrfs_wake_unfinished_drop(fs_info);
4499 
4500 	/*
4501 	 * We may have the reclaim task running and relocating a data block group,
4502 	 * in which case it may create delayed iputs. So stop it before we park
4503 	 * the cleaner kthread otherwise we can get new delayed iputs after
4504 	 * parking the cleaner, and that can make the async reclaim task to hang
4505 	 * if it's waiting for delayed iputs to complete, since the cleaner is
4506 	 * parked and can not run delayed iputs - this will make us hang when
4507 	 * trying to stop the async reclaim task.
4508 	 */
4509 	cancel_work_sync(&fs_info->reclaim_bgs_work);
4510 	/*
4511 	 * We don't want the cleaner to start new transactions, add more delayed
4512 	 * iputs, etc. while we're closing. We can't use kthread_stop() yet
4513 	 * because that frees the task_struct, and the transaction kthread might
4514 	 * still try to wake up the cleaner.
4515 	 */
4516 	kthread_park(fs_info->cleaner_kthread);
4517 
4518 	/* wait for the qgroup rescan worker to stop */
4519 	btrfs_qgroup_wait_for_completion(fs_info, false);
4520 
4521 	/* wait for the uuid_scan task to finish */
4522 	down(&fs_info->uuid_tree_rescan_sem);
4523 	/* avoid complains from lockdep et al., set sem back to initial state */
4524 	up(&fs_info->uuid_tree_rescan_sem);
4525 
4526 	/* pause restriper - we want to resume on mount */
4527 	btrfs_pause_balance(fs_info);
4528 
4529 	btrfs_dev_replace_suspend_for_unmount(fs_info);
4530 
4531 	btrfs_scrub_cancel(fs_info);
4532 
4533 	/* wait for any defraggers to finish */
4534 	wait_event(fs_info->transaction_wait,
4535 		   (atomic_read(&fs_info->defrag_running) == 0));
4536 
4537 	/* clear out the rbtree of defraggable inodes */
4538 	btrfs_cleanup_defrag_inodes(fs_info);
4539 
4540 	/*
4541 	 * After we parked the cleaner kthread, ordered extents may have
4542 	 * completed and created new delayed iputs. If one of the async reclaim
4543 	 * tasks is running and in the RUN_DELAYED_IPUTS flush state, then we
4544 	 * can hang forever trying to stop it, because if a delayed iput is
4545 	 * added after it ran btrfs_run_delayed_iputs() and before it called
4546 	 * btrfs_wait_on_delayed_iputs(), it will hang forever since there is
4547 	 * no one else to run iputs.
4548 	 *
4549 	 * So wait for all ongoing ordered extents to complete and then run
4550 	 * delayed iputs. This works because once we reach this point no one
4551 	 * can either create new ordered extents nor create delayed iputs
4552 	 * through some other means.
4553 	 *
4554 	 * Also note that btrfs_wait_ordered_roots() is not safe here, because
4555 	 * it waits for BTRFS_ORDERED_COMPLETE to be set on an ordered extent,
4556 	 * but the delayed iput for the respective inode is made only when doing
4557 	 * the final btrfs_put_ordered_extent() (which must happen at
4558 	 * btrfs_finish_ordered_io() when we are unmounting).
4559 	 */
4560 	btrfs_flush_workqueue(fs_info->endio_write_workers);
4561 	/* Ordered extents for free space inodes. */
4562 	btrfs_flush_workqueue(fs_info->endio_freespace_worker);
4563 	btrfs_run_delayed_iputs(fs_info);
4564 
4565 	cancel_work_sync(&fs_info->async_reclaim_work);
4566 	cancel_work_sync(&fs_info->async_data_reclaim_work);
4567 	cancel_work_sync(&fs_info->preempt_reclaim_work);
4568 
4569 	/* Cancel or finish ongoing discard work */
4570 	btrfs_discard_cleanup(fs_info);
4571 
4572 	if (!sb_rdonly(fs_info->sb)) {
4573 		/*
4574 		 * The cleaner kthread is stopped, so do one final pass over
4575 		 * unused block groups.
4576 		 */
4577 		btrfs_delete_unused_bgs(fs_info);
4578 
4579 		/*
4580 		 * There might be existing delayed inode workers still running
4581 		 * and holding an empty delayed inode item. We must wait for
4582 		 * them to complete first because they can create a transaction.
4583 		 * This happens when someone calls btrfs_balance_delayed_items()
4584 		 * and then a transaction commit runs the same delayed nodes
4585 		 * before any delayed worker has done something with the nodes.
4586 		 * We must wait for any worker here and not at transaction
4587 		 * commit time since that could cause a deadlock.
4588 		 * This is a very rare case.
4589 		 */
4590 		btrfs_flush_workqueue(fs_info->delayed_workers);
4591 
4592 		ret = btrfs_commit_super(fs_info);
4593 		if (ret)
4594 			btrfs_err(fs_info, "commit super ret %d", ret);
4595 	}
4596 
4597 	if (BTRFS_FS_ERROR(fs_info))
4598 		btrfs_error_commit_super(fs_info);
4599 
4600 	kthread_stop(fs_info->transaction_kthread);
4601 	kthread_stop(fs_info->cleaner_kthread);
4602 
4603 	ASSERT(list_empty(&fs_info->delayed_iputs));
4604 	set_bit(BTRFS_FS_CLOSING_DONE, &fs_info->flags);
4605 
4606 	if (btrfs_check_quota_leak(fs_info)) {
4607 		WARN_ON(IS_ENABLED(CONFIG_BTRFS_DEBUG));
4608 		btrfs_err(fs_info, "qgroup reserved space leaked");
4609 	}
4610 
4611 	btrfs_free_qgroup_config(fs_info);
4612 	ASSERT(list_empty(&fs_info->delalloc_roots));
4613 
4614 	if (percpu_counter_sum(&fs_info->delalloc_bytes)) {
4615 		btrfs_info(fs_info, "at unmount delalloc count %lld",
4616 		       percpu_counter_sum(&fs_info->delalloc_bytes));
4617 	}
4618 
4619 	if (percpu_counter_sum(&fs_info->ordered_bytes))
4620 		btrfs_info(fs_info, "at unmount dio bytes count %lld",
4621 			   percpu_counter_sum(&fs_info->ordered_bytes));
4622 
4623 	btrfs_sysfs_remove_mounted(fs_info);
4624 	btrfs_sysfs_remove_fsid(fs_info->fs_devices);
4625 
4626 	btrfs_put_block_group_cache(fs_info);
4627 
4628 	/*
4629 	 * we must make sure there is not any read request to
4630 	 * submit after we stopping all workers.
4631 	 */
4632 	invalidate_inode_pages2(fs_info->btree_inode->i_mapping);
4633 	btrfs_stop_all_workers(fs_info);
4634 
4635 	/* We shouldn't have any transaction open at this point */
4636 	warn_about_uncommitted_trans(fs_info);
4637 
4638 	clear_bit(BTRFS_FS_OPEN, &fs_info->flags);
4639 	free_root_pointers(fs_info, true);
4640 	btrfs_free_fs_roots(fs_info);
4641 
4642 	/*
4643 	 * We must free the block groups after dropping the fs_roots as we could
4644 	 * have had an IO error and have left over tree log blocks that aren't
4645 	 * cleaned up until the fs roots are freed.  This makes the block group
4646 	 * accounting appear to be wrong because there's pending reserved bytes,
4647 	 * so make sure we do the block group cleanup afterwards.
4648 	 */
4649 	btrfs_free_block_groups(fs_info);
4650 
4651 	iput(fs_info->btree_inode);
4652 
4653 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
4654 	if (btrfs_test_opt(fs_info, CHECK_INTEGRITY))
4655 		btrfsic_unmount(fs_info->fs_devices);
4656 #endif
4657 
4658 	btrfs_mapping_tree_free(&fs_info->mapping_tree);
4659 	btrfs_close_devices(fs_info->fs_devices);
4660 }
4661 
4662 int btrfs_buffer_uptodate(struct extent_buffer *buf, u64 parent_transid,
4663 			  int atomic)
4664 {
4665 	int ret;
4666 	struct inode *btree_inode = buf->pages[0]->mapping->host;
4667 
4668 	ret = extent_buffer_uptodate(buf);
4669 	if (!ret)
4670 		return ret;
4671 
4672 	ret = verify_parent_transid(&BTRFS_I(btree_inode)->io_tree, buf,
4673 				    parent_transid, atomic);
4674 	if (ret == -EAGAIN)
4675 		return ret;
4676 	return !ret;
4677 }
4678 
4679 void btrfs_mark_buffer_dirty(struct extent_buffer *buf)
4680 {
4681 	struct btrfs_fs_info *fs_info = buf->fs_info;
4682 	u64 transid = btrfs_header_generation(buf);
4683 	int was_dirty;
4684 
4685 #ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
4686 	/*
4687 	 * This is a fast path so only do this check if we have sanity tests
4688 	 * enabled.  Normal people shouldn't be using unmapped buffers as dirty
4689 	 * outside of the sanity tests.
4690 	 */
4691 	if (unlikely(test_bit(EXTENT_BUFFER_UNMAPPED, &buf->bflags)))
4692 		return;
4693 #endif
4694 	btrfs_assert_tree_write_locked(buf);
4695 	if (transid != fs_info->generation)
4696 		WARN(1, KERN_CRIT "btrfs transid mismatch buffer %llu, found %llu running %llu\n",
4697 			buf->start, transid, fs_info->generation);
4698 	was_dirty = set_extent_buffer_dirty(buf);
4699 	if (!was_dirty)
4700 		percpu_counter_add_batch(&fs_info->dirty_metadata_bytes,
4701 					 buf->len,
4702 					 fs_info->dirty_metadata_batch);
4703 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
4704 	/*
4705 	 * Since btrfs_mark_buffer_dirty() can be called with item pointer set
4706 	 * but item data not updated.
4707 	 * So here we should only check item pointers, not item data.
4708 	 */
4709 	if (btrfs_header_level(buf) == 0 &&
4710 	    btrfs_check_leaf_relaxed(buf)) {
4711 		btrfs_print_leaf(buf);
4712 		ASSERT(0);
4713 	}
4714 #endif
4715 }
4716 
4717 static void __btrfs_btree_balance_dirty(struct btrfs_fs_info *fs_info,
4718 					int flush_delayed)
4719 {
4720 	/*
4721 	 * looks as though older kernels can get into trouble with
4722 	 * this code, they end up stuck in balance_dirty_pages forever
4723 	 */
4724 	int ret;
4725 
4726 	if (current->flags & PF_MEMALLOC)
4727 		return;
4728 
4729 	if (flush_delayed)
4730 		btrfs_balance_delayed_items(fs_info);
4731 
4732 	ret = __percpu_counter_compare(&fs_info->dirty_metadata_bytes,
4733 				     BTRFS_DIRTY_METADATA_THRESH,
4734 				     fs_info->dirty_metadata_batch);
4735 	if (ret > 0) {
4736 		balance_dirty_pages_ratelimited(fs_info->btree_inode->i_mapping);
4737 	}
4738 }
4739 
4740 void btrfs_btree_balance_dirty(struct btrfs_fs_info *fs_info)
4741 {
4742 	__btrfs_btree_balance_dirty(fs_info, 1);
4743 }
4744 
4745 void btrfs_btree_balance_dirty_nodelay(struct btrfs_fs_info *fs_info)
4746 {
4747 	__btrfs_btree_balance_dirty(fs_info, 0);
4748 }
4749 
4750 static void btrfs_error_commit_super(struct btrfs_fs_info *fs_info)
4751 {
4752 	/* cleanup FS via transaction */
4753 	btrfs_cleanup_transaction(fs_info);
4754 
4755 	mutex_lock(&fs_info->cleaner_mutex);
4756 	btrfs_run_delayed_iputs(fs_info);
4757 	mutex_unlock(&fs_info->cleaner_mutex);
4758 
4759 	down_write(&fs_info->cleanup_work_sem);
4760 	up_write(&fs_info->cleanup_work_sem);
4761 }
4762 
4763 static void btrfs_drop_all_logs(struct btrfs_fs_info *fs_info)
4764 {
4765 	struct btrfs_root *gang[8];
4766 	u64 root_objectid = 0;
4767 	int ret;
4768 
4769 	spin_lock(&fs_info->fs_roots_radix_lock);
4770 	while ((ret = radix_tree_gang_lookup(&fs_info->fs_roots_radix,
4771 					     (void **)gang, root_objectid,
4772 					     ARRAY_SIZE(gang))) != 0) {
4773 		int i;
4774 
4775 		for (i = 0; i < ret; i++)
4776 			gang[i] = btrfs_grab_root(gang[i]);
4777 		spin_unlock(&fs_info->fs_roots_radix_lock);
4778 
4779 		for (i = 0; i < ret; i++) {
4780 			if (!gang[i])
4781 				continue;
4782 			root_objectid = gang[i]->root_key.objectid;
4783 			btrfs_free_log(NULL, gang[i]);
4784 			btrfs_put_root(gang[i]);
4785 		}
4786 		root_objectid++;
4787 		spin_lock(&fs_info->fs_roots_radix_lock);
4788 	}
4789 	spin_unlock(&fs_info->fs_roots_radix_lock);
4790 	btrfs_free_log_root_tree(NULL, fs_info);
4791 }
4792 
4793 static void btrfs_destroy_ordered_extents(struct btrfs_root *root)
4794 {
4795 	struct btrfs_ordered_extent *ordered;
4796 
4797 	spin_lock(&root->ordered_extent_lock);
4798 	/*
4799 	 * This will just short circuit the ordered completion stuff which will
4800 	 * make sure the ordered extent gets properly cleaned up.
4801 	 */
4802 	list_for_each_entry(ordered, &root->ordered_extents,
4803 			    root_extent_list)
4804 		set_bit(BTRFS_ORDERED_IOERR, &ordered->flags);
4805 	spin_unlock(&root->ordered_extent_lock);
4806 }
4807 
4808 static void btrfs_destroy_all_ordered_extents(struct btrfs_fs_info *fs_info)
4809 {
4810 	struct btrfs_root *root;
4811 	struct list_head splice;
4812 
4813 	INIT_LIST_HEAD(&splice);
4814 
4815 	spin_lock(&fs_info->ordered_root_lock);
4816 	list_splice_init(&fs_info->ordered_roots, &splice);
4817 	while (!list_empty(&splice)) {
4818 		root = list_first_entry(&splice, struct btrfs_root,
4819 					ordered_root);
4820 		list_move_tail(&root->ordered_root,
4821 			       &fs_info->ordered_roots);
4822 
4823 		spin_unlock(&fs_info->ordered_root_lock);
4824 		btrfs_destroy_ordered_extents(root);
4825 
4826 		cond_resched();
4827 		spin_lock(&fs_info->ordered_root_lock);
4828 	}
4829 	spin_unlock(&fs_info->ordered_root_lock);
4830 
4831 	/*
4832 	 * We need this here because if we've been flipped read-only we won't
4833 	 * get sync() from the umount, so we need to make sure any ordered
4834 	 * extents that haven't had their dirty pages IO start writeout yet
4835 	 * actually get run and error out properly.
4836 	 */
4837 	btrfs_wait_ordered_roots(fs_info, U64_MAX, 0, (u64)-1);
4838 }
4839 
4840 static int btrfs_destroy_delayed_refs(struct btrfs_transaction *trans,
4841 				      struct btrfs_fs_info *fs_info)
4842 {
4843 	struct rb_node *node;
4844 	struct btrfs_delayed_ref_root *delayed_refs;
4845 	struct btrfs_delayed_ref_node *ref;
4846 	int ret = 0;
4847 
4848 	delayed_refs = &trans->delayed_refs;
4849 
4850 	spin_lock(&delayed_refs->lock);
4851 	if (atomic_read(&delayed_refs->num_entries) == 0) {
4852 		spin_unlock(&delayed_refs->lock);
4853 		btrfs_debug(fs_info, "delayed_refs has NO entry");
4854 		return ret;
4855 	}
4856 
4857 	while ((node = rb_first_cached(&delayed_refs->href_root)) != NULL) {
4858 		struct btrfs_delayed_ref_head *head;
4859 		struct rb_node *n;
4860 		bool pin_bytes = false;
4861 
4862 		head = rb_entry(node, struct btrfs_delayed_ref_head,
4863 				href_node);
4864 		if (btrfs_delayed_ref_lock(delayed_refs, head))
4865 			continue;
4866 
4867 		spin_lock(&head->lock);
4868 		while ((n = rb_first_cached(&head->ref_tree)) != NULL) {
4869 			ref = rb_entry(n, struct btrfs_delayed_ref_node,
4870 				       ref_node);
4871 			ref->in_tree = 0;
4872 			rb_erase_cached(&ref->ref_node, &head->ref_tree);
4873 			RB_CLEAR_NODE(&ref->ref_node);
4874 			if (!list_empty(&ref->add_list))
4875 				list_del(&ref->add_list);
4876 			atomic_dec(&delayed_refs->num_entries);
4877 			btrfs_put_delayed_ref(ref);
4878 		}
4879 		if (head->must_insert_reserved)
4880 			pin_bytes = true;
4881 		btrfs_free_delayed_extent_op(head->extent_op);
4882 		btrfs_delete_ref_head(delayed_refs, head);
4883 		spin_unlock(&head->lock);
4884 		spin_unlock(&delayed_refs->lock);
4885 		mutex_unlock(&head->mutex);
4886 
4887 		if (pin_bytes) {
4888 			struct btrfs_block_group *cache;
4889 
4890 			cache = btrfs_lookup_block_group(fs_info, head->bytenr);
4891 			BUG_ON(!cache);
4892 
4893 			spin_lock(&cache->space_info->lock);
4894 			spin_lock(&cache->lock);
4895 			cache->pinned += head->num_bytes;
4896 			btrfs_space_info_update_bytes_pinned(fs_info,
4897 				cache->space_info, head->num_bytes);
4898 			cache->reserved -= head->num_bytes;
4899 			cache->space_info->bytes_reserved -= head->num_bytes;
4900 			spin_unlock(&cache->lock);
4901 			spin_unlock(&cache->space_info->lock);
4902 
4903 			btrfs_put_block_group(cache);
4904 
4905 			btrfs_error_unpin_extent_range(fs_info, head->bytenr,
4906 				head->bytenr + head->num_bytes - 1);
4907 		}
4908 		btrfs_cleanup_ref_head_accounting(fs_info, delayed_refs, head);
4909 		btrfs_put_delayed_ref_head(head);
4910 		cond_resched();
4911 		spin_lock(&delayed_refs->lock);
4912 	}
4913 	btrfs_qgroup_destroy_extent_records(trans);
4914 
4915 	spin_unlock(&delayed_refs->lock);
4916 
4917 	return ret;
4918 }
4919 
4920 static void btrfs_destroy_delalloc_inodes(struct btrfs_root *root)
4921 {
4922 	struct btrfs_inode *btrfs_inode;
4923 	struct list_head splice;
4924 
4925 	INIT_LIST_HEAD(&splice);
4926 
4927 	spin_lock(&root->delalloc_lock);
4928 	list_splice_init(&root->delalloc_inodes, &splice);
4929 
4930 	while (!list_empty(&splice)) {
4931 		struct inode *inode = NULL;
4932 		btrfs_inode = list_first_entry(&splice, struct btrfs_inode,
4933 					       delalloc_inodes);
4934 		__btrfs_del_delalloc_inode(root, btrfs_inode);
4935 		spin_unlock(&root->delalloc_lock);
4936 
4937 		/*
4938 		 * Make sure we get a live inode and that it'll not disappear
4939 		 * meanwhile.
4940 		 */
4941 		inode = igrab(&btrfs_inode->vfs_inode);
4942 		if (inode) {
4943 			invalidate_inode_pages2(inode->i_mapping);
4944 			iput(inode);
4945 		}
4946 		spin_lock(&root->delalloc_lock);
4947 	}
4948 	spin_unlock(&root->delalloc_lock);
4949 }
4950 
4951 static void btrfs_destroy_all_delalloc_inodes(struct btrfs_fs_info *fs_info)
4952 {
4953 	struct btrfs_root *root;
4954 	struct list_head splice;
4955 
4956 	INIT_LIST_HEAD(&splice);
4957 
4958 	spin_lock(&fs_info->delalloc_root_lock);
4959 	list_splice_init(&fs_info->delalloc_roots, &splice);
4960 	while (!list_empty(&splice)) {
4961 		root = list_first_entry(&splice, struct btrfs_root,
4962 					 delalloc_root);
4963 		root = btrfs_grab_root(root);
4964 		BUG_ON(!root);
4965 		spin_unlock(&fs_info->delalloc_root_lock);
4966 
4967 		btrfs_destroy_delalloc_inodes(root);
4968 		btrfs_put_root(root);
4969 
4970 		spin_lock(&fs_info->delalloc_root_lock);
4971 	}
4972 	spin_unlock(&fs_info->delalloc_root_lock);
4973 }
4974 
4975 static int btrfs_destroy_marked_extents(struct btrfs_fs_info *fs_info,
4976 					struct extent_io_tree *dirty_pages,
4977 					int mark)
4978 {
4979 	int ret;
4980 	struct extent_buffer *eb;
4981 	u64 start = 0;
4982 	u64 end;
4983 
4984 	while (1) {
4985 		ret = find_first_extent_bit(dirty_pages, start, &start, &end,
4986 					    mark, NULL);
4987 		if (ret)
4988 			break;
4989 
4990 		clear_extent_bits(dirty_pages, start, end, mark);
4991 		while (start <= end) {
4992 			eb = find_extent_buffer(fs_info, start);
4993 			start += fs_info->nodesize;
4994 			if (!eb)
4995 				continue;
4996 
4997 			btrfs_tree_lock(eb);
4998 			wait_on_extent_buffer_writeback(eb);
4999 			btrfs_clear_buffer_dirty(NULL, eb);
5000 			btrfs_tree_unlock(eb);
5001 
5002 			free_extent_buffer_stale(eb);
5003 		}
5004 	}
5005 
5006 	return ret;
5007 }
5008 
5009 static int btrfs_destroy_pinned_extent(struct btrfs_fs_info *fs_info,
5010 				       struct extent_io_tree *unpin)
5011 {
5012 	u64 start;
5013 	u64 end;
5014 	int ret;
5015 
5016 	while (1) {
5017 		struct extent_state *cached_state = NULL;
5018 
5019 		/*
5020 		 * The btrfs_finish_extent_commit() may get the same range as
5021 		 * ours between find_first_extent_bit and clear_extent_dirty.
5022 		 * Hence, hold the unused_bg_unpin_mutex to avoid double unpin
5023 		 * the same extent range.
5024 		 */
5025 		mutex_lock(&fs_info->unused_bg_unpin_mutex);
5026 		ret = find_first_extent_bit(unpin, 0, &start, &end,
5027 					    EXTENT_DIRTY, &cached_state);
5028 		if (ret) {
5029 			mutex_unlock(&fs_info->unused_bg_unpin_mutex);
5030 			break;
5031 		}
5032 
5033 		clear_extent_dirty(unpin, start, end, &cached_state);
5034 		free_extent_state(cached_state);
5035 		btrfs_error_unpin_extent_range(fs_info, start, end);
5036 		mutex_unlock(&fs_info->unused_bg_unpin_mutex);
5037 		cond_resched();
5038 	}
5039 
5040 	return 0;
5041 }
5042 
5043 static void btrfs_cleanup_bg_io(struct btrfs_block_group *cache)
5044 {
5045 	struct inode *inode;
5046 
5047 	inode = cache->io_ctl.inode;
5048 	if (inode) {
5049 		invalidate_inode_pages2(inode->i_mapping);
5050 		BTRFS_I(inode)->generation = 0;
5051 		cache->io_ctl.inode = NULL;
5052 		iput(inode);
5053 	}
5054 	ASSERT(cache->io_ctl.pages == NULL);
5055 	btrfs_put_block_group(cache);
5056 }
5057 
5058 void btrfs_cleanup_dirty_bgs(struct btrfs_transaction *cur_trans,
5059 			     struct btrfs_fs_info *fs_info)
5060 {
5061 	struct btrfs_block_group *cache;
5062 
5063 	spin_lock(&cur_trans->dirty_bgs_lock);
5064 	while (!list_empty(&cur_trans->dirty_bgs)) {
5065 		cache = list_first_entry(&cur_trans->dirty_bgs,
5066 					 struct btrfs_block_group,
5067 					 dirty_list);
5068 
5069 		if (!list_empty(&cache->io_list)) {
5070 			spin_unlock(&cur_trans->dirty_bgs_lock);
5071 			list_del_init(&cache->io_list);
5072 			btrfs_cleanup_bg_io(cache);
5073 			spin_lock(&cur_trans->dirty_bgs_lock);
5074 		}
5075 
5076 		list_del_init(&cache->dirty_list);
5077 		spin_lock(&cache->lock);
5078 		cache->disk_cache_state = BTRFS_DC_ERROR;
5079 		spin_unlock(&cache->lock);
5080 
5081 		spin_unlock(&cur_trans->dirty_bgs_lock);
5082 		btrfs_put_block_group(cache);
5083 		btrfs_delayed_refs_rsv_release(fs_info, 1);
5084 		spin_lock(&cur_trans->dirty_bgs_lock);
5085 	}
5086 	spin_unlock(&cur_trans->dirty_bgs_lock);
5087 
5088 	/*
5089 	 * Refer to the definition of io_bgs member for details why it's safe
5090 	 * to use it without any locking
5091 	 */
5092 	while (!list_empty(&cur_trans->io_bgs)) {
5093 		cache = list_first_entry(&cur_trans->io_bgs,
5094 					 struct btrfs_block_group,
5095 					 io_list);
5096 
5097 		list_del_init(&cache->io_list);
5098 		spin_lock(&cache->lock);
5099 		cache->disk_cache_state = BTRFS_DC_ERROR;
5100 		spin_unlock(&cache->lock);
5101 		btrfs_cleanup_bg_io(cache);
5102 	}
5103 }
5104 
5105 void btrfs_cleanup_one_transaction(struct btrfs_transaction *cur_trans,
5106 				   struct btrfs_fs_info *fs_info)
5107 {
5108 	struct btrfs_device *dev, *tmp;
5109 
5110 	btrfs_cleanup_dirty_bgs(cur_trans, fs_info);
5111 	ASSERT(list_empty(&cur_trans->dirty_bgs));
5112 	ASSERT(list_empty(&cur_trans->io_bgs));
5113 
5114 	list_for_each_entry_safe(dev, tmp, &cur_trans->dev_update_list,
5115 				 post_commit_list) {
5116 		list_del_init(&dev->post_commit_list);
5117 	}
5118 
5119 	btrfs_destroy_delayed_refs(cur_trans, fs_info);
5120 
5121 	cur_trans->state = TRANS_STATE_COMMIT_START;
5122 	wake_up(&fs_info->transaction_blocked_wait);
5123 
5124 	cur_trans->state = TRANS_STATE_UNBLOCKED;
5125 	wake_up(&fs_info->transaction_wait);
5126 
5127 	btrfs_destroy_delayed_inodes(fs_info);
5128 
5129 	btrfs_destroy_marked_extents(fs_info, &cur_trans->dirty_pages,
5130 				     EXTENT_DIRTY);
5131 	btrfs_destroy_pinned_extent(fs_info, &cur_trans->pinned_extents);
5132 
5133 	btrfs_free_redirty_list(cur_trans);
5134 
5135 	cur_trans->state =TRANS_STATE_COMPLETED;
5136 	wake_up(&cur_trans->commit_wait);
5137 }
5138 
5139 static int btrfs_cleanup_transaction(struct btrfs_fs_info *fs_info)
5140 {
5141 	struct btrfs_transaction *t;
5142 
5143 	mutex_lock(&fs_info->transaction_kthread_mutex);
5144 
5145 	spin_lock(&fs_info->trans_lock);
5146 	while (!list_empty(&fs_info->trans_list)) {
5147 		t = list_first_entry(&fs_info->trans_list,
5148 				     struct btrfs_transaction, list);
5149 		if (t->state >= TRANS_STATE_COMMIT_START) {
5150 			refcount_inc(&t->use_count);
5151 			spin_unlock(&fs_info->trans_lock);
5152 			btrfs_wait_for_commit(fs_info, t->transid);
5153 			btrfs_put_transaction(t);
5154 			spin_lock(&fs_info->trans_lock);
5155 			continue;
5156 		}
5157 		if (t == fs_info->running_transaction) {
5158 			t->state = TRANS_STATE_COMMIT_DOING;
5159 			spin_unlock(&fs_info->trans_lock);
5160 			/*
5161 			 * We wait for 0 num_writers since we don't hold a trans
5162 			 * handle open currently for this transaction.
5163 			 */
5164 			wait_event(t->writer_wait,
5165 				   atomic_read(&t->num_writers) == 0);
5166 		} else {
5167 			spin_unlock(&fs_info->trans_lock);
5168 		}
5169 		btrfs_cleanup_one_transaction(t, fs_info);
5170 
5171 		spin_lock(&fs_info->trans_lock);
5172 		if (t == fs_info->running_transaction)
5173 			fs_info->running_transaction = NULL;
5174 		list_del_init(&t->list);
5175 		spin_unlock(&fs_info->trans_lock);
5176 
5177 		btrfs_put_transaction(t);
5178 		trace_btrfs_transaction_commit(fs_info);
5179 		spin_lock(&fs_info->trans_lock);
5180 	}
5181 	spin_unlock(&fs_info->trans_lock);
5182 	btrfs_destroy_all_ordered_extents(fs_info);
5183 	btrfs_destroy_delayed_inodes(fs_info);
5184 	btrfs_assert_delayed_root_empty(fs_info);
5185 	btrfs_destroy_all_delalloc_inodes(fs_info);
5186 	btrfs_drop_all_logs(fs_info);
5187 	mutex_unlock(&fs_info->transaction_kthread_mutex);
5188 
5189 	return 0;
5190 }
5191 
5192 int btrfs_init_root_free_objectid(struct btrfs_root *root)
5193 {
5194 	struct btrfs_path *path;
5195 	int ret;
5196 	struct extent_buffer *l;
5197 	struct btrfs_key search_key;
5198 	struct btrfs_key found_key;
5199 	int slot;
5200 
5201 	path = btrfs_alloc_path();
5202 	if (!path)
5203 		return -ENOMEM;
5204 
5205 	search_key.objectid = BTRFS_LAST_FREE_OBJECTID;
5206 	search_key.type = -1;
5207 	search_key.offset = (u64)-1;
5208 	ret = btrfs_search_slot(NULL, root, &search_key, path, 0, 0);
5209 	if (ret < 0)
5210 		goto error;
5211 	BUG_ON(ret == 0); /* Corruption */
5212 	if (path->slots[0] > 0) {
5213 		slot = path->slots[0] - 1;
5214 		l = path->nodes[0];
5215 		btrfs_item_key_to_cpu(l, &found_key, slot);
5216 		root->free_objectid = max_t(u64, found_key.objectid + 1,
5217 					    BTRFS_FIRST_FREE_OBJECTID);
5218 	} else {
5219 		root->free_objectid = BTRFS_FIRST_FREE_OBJECTID;
5220 	}
5221 	ret = 0;
5222 error:
5223 	btrfs_free_path(path);
5224 	return ret;
5225 }
5226 
5227 int btrfs_get_free_objectid(struct btrfs_root *root, u64 *objectid)
5228 {
5229 	int ret;
5230 	mutex_lock(&root->objectid_mutex);
5231 
5232 	if (unlikely(root->free_objectid >= BTRFS_LAST_FREE_OBJECTID)) {
5233 		btrfs_warn(root->fs_info,
5234 			   "the objectid of root %llu reaches its highest value",
5235 			   root->root_key.objectid);
5236 		ret = -ENOSPC;
5237 		goto out;
5238 	}
5239 
5240 	*objectid = root->free_objectid++;
5241 	ret = 0;
5242 out:
5243 	mutex_unlock(&root->objectid_mutex);
5244 	return ret;
5245 }
5246