xref: /linux/fs/btrfs/disk-io.c (revision 988b0c541ed8b1c633c4d4df7169010635942e18)
1 /*
2  * Copyright (C) 2007 Oracle.  All rights reserved.
3  *
4  * This program is free software; you can redistribute it and/or
5  * modify it under the terms of the GNU General Public
6  * License v2 as published by the Free Software Foundation.
7  *
8  * This program is distributed in the hope that it will be useful,
9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
11  * General Public License for more details.
12  *
13  * You should have received a copy of the GNU General Public
14  * License along with this program; if not, write to the
15  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
16  * Boston, MA 021110-1307, USA.
17  */
18 
19 #include <linux/fs.h>
20 #include <linux/blkdev.h>
21 #include <linux/scatterlist.h>
22 #include <linux/swap.h>
23 #include <linux/radix-tree.h>
24 #include <linux/writeback.h>
25 #include <linux/buffer_head.h>
26 #include <linux/workqueue.h>
27 #include <linux/kthread.h>
28 #include <linux/freezer.h>
29 #include <linux/slab.h>
30 #include <linux/migrate.h>
31 #include <linux/ratelimit.h>
32 #include <linux/uuid.h>
33 #include <linux/semaphore.h>
34 #include <asm/unaligned.h>
35 #include "ctree.h"
36 #include "disk-io.h"
37 #include "hash.h"
38 #include "transaction.h"
39 #include "btrfs_inode.h"
40 #include "volumes.h"
41 #include "print-tree.h"
42 #include "async-thread.h"
43 #include "locking.h"
44 #include "tree-log.h"
45 #include "free-space-cache.h"
46 #include "inode-map.h"
47 #include "check-integrity.h"
48 #include "rcu-string.h"
49 #include "dev-replace.h"
50 #include "raid56.h"
51 #include "sysfs.h"
52 #include "qgroup.h"
53 
54 #ifdef CONFIG_X86
55 #include <asm/cpufeature.h>
56 #endif
57 
58 static struct extent_io_ops btree_extent_io_ops;
59 static void end_workqueue_fn(struct btrfs_work *work);
60 static void free_fs_root(struct btrfs_root *root);
61 static int btrfs_check_super_valid(struct btrfs_fs_info *fs_info,
62 				    int read_only);
63 static void btrfs_destroy_ordered_operations(struct btrfs_transaction *t,
64 					     struct btrfs_root *root);
65 static void btrfs_destroy_ordered_extents(struct btrfs_root *root);
66 static int btrfs_destroy_delayed_refs(struct btrfs_transaction *trans,
67 				      struct btrfs_root *root);
68 static void btrfs_destroy_delalloc_inodes(struct btrfs_root *root);
69 static int btrfs_destroy_marked_extents(struct btrfs_root *root,
70 					struct extent_io_tree *dirty_pages,
71 					int mark);
72 static int btrfs_destroy_pinned_extent(struct btrfs_root *root,
73 				       struct extent_io_tree *pinned_extents);
74 static int btrfs_cleanup_transaction(struct btrfs_root *root);
75 static void btrfs_error_commit_super(struct btrfs_root *root);
76 
77 /*
78  * end_io_wq structs are used to do processing in task context when an IO is
79  * complete.  This is used during reads to verify checksums, and it is used
80  * by writes to insert metadata for new file extents after IO is complete.
81  */
82 struct end_io_wq {
83 	struct bio *bio;
84 	bio_end_io_t *end_io;
85 	void *private;
86 	struct btrfs_fs_info *info;
87 	int error;
88 	int metadata;
89 	struct list_head list;
90 	struct btrfs_work work;
91 };
92 
93 /*
94  * async submit bios are used to offload expensive checksumming
95  * onto the worker threads.  They checksum file and metadata bios
96  * just before they are sent down the IO stack.
97  */
98 struct async_submit_bio {
99 	struct inode *inode;
100 	struct bio *bio;
101 	struct list_head list;
102 	extent_submit_bio_hook_t *submit_bio_start;
103 	extent_submit_bio_hook_t *submit_bio_done;
104 	int rw;
105 	int mirror_num;
106 	unsigned long bio_flags;
107 	/*
108 	 * bio_offset is optional, can be used if the pages in the bio
109 	 * can't tell us where in the file the bio should go
110 	 */
111 	u64 bio_offset;
112 	struct btrfs_work work;
113 	int error;
114 };
115 
116 /*
117  * Lockdep class keys for extent_buffer->lock's in this root.  For a given
118  * eb, the lockdep key is determined by the btrfs_root it belongs to and
119  * the level the eb occupies in the tree.
120  *
121  * Different roots are used for different purposes and may nest inside each
122  * other and they require separate keysets.  As lockdep keys should be
123  * static, assign keysets according to the purpose of the root as indicated
124  * by btrfs_root->objectid.  This ensures that all special purpose roots
125  * have separate keysets.
126  *
127  * Lock-nesting across peer nodes is always done with the immediate parent
128  * node locked thus preventing deadlock.  As lockdep doesn't know this, use
129  * subclass to avoid triggering lockdep warning in such cases.
130  *
131  * The key is set by the readpage_end_io_hook after the buffer has passed
132  * csum validation but before the pages are unlocked.  It is also set by
133  * btrfs_init_new_buffer on freshly allocated blocks.
134  *
135  * We also add a check to make sure the highest level of the tree is the
136  * same as our lockdep setup here.  If BTRFS_MAX_LEVEL changes, this code
137  * needs update as well.
138  */
139 #ifdef CONFIG_DEBUG_LOCK_ALLOC
140 # if BTRFS_MAX_LEVEL != 8
141 #  error
142 # endif
143 
144 static struct btrfs_lockdep_keyset {
145 	u64			id;		/* root objectid */
146 	const char		*name_stem;	/* lock name stem */
147 	char			names[BTRFS_MAX_LEVEL + 1][20];
148 	struct lock_class_key	keys[BTRFS_MAX_LEVEL + 1];
149 } btrfs_lockdep_keysets[] = {
150 	{ .id = BTRFS_ROOT_TREE_OBJECTID,	.name_stem = "root"	},
151 	{ .id = BTRFS_EXTENT_TREE_OBJECTID,	.name_stem = "extent"	},
152 	{ .id = BTRFS_CHUNK_TREE_OBJECTID,	.name_stem = "chunk"	},
153 	{ .id = BTRFS_DEV_TREE_OBJECTID,	.name_stem = "dev"	},
154 	{ .id = BTRFS_FS_TREE_OBJECTID,		.name_stem = "fs"	},
155 	{ .id = BTRFS_CSUM_TREE_OBJECTID,	.name_stem = "csum"	},
156 	{ .id = BTRFS_QUOTA_TREE_OBJECTID,	.name_stem = "quota"	},
157 	{ .id = BTRFS_TREE_LOG_OBJECTID,	.name_stem = "log"	},
158 	{ .id = BTRFS_TREE_RELOC_OBJECTID,	.name_stem = "treloc"	},
159 	{ .id = BTRFS_DATA_RELOC_TREE_OBJECTID,	.name_stem = "dreloc"	},
160 	{ .id = BTRFS_UUID_TREE_OBJECTID,	.name_stem = "uuid"	},
161 	{ .id = 0,				.name_stem = "tree"	},
162 };
163 
164 void __init btrfs_init_lockdep(void)
165 {
166 	int i, j;
167 
168 	/* initialize lockdep class names */
169 	for (i = 0; i < ARRAY_SIZE(btrfs_lockdep_keysets); i++) {
170 		struct btrfs_lockdep_keyset *ks = &btrfs_lockdep_keysets[i];
171 
172 		for (j = 0; j < ARRAY_SIZE(ks->names); j++)
173 			snprintf(ks->names[j], sizeof(ks->names[j]),
174 				 "btrfs-%s-%02d", ks->name_stem, j);
175 	}
176 }
177 
178 void btrfs_set_buffer_lockdep_class(u64 objectid, struct extent_buffer *eb,
179 				    int level)
180 {
181 	struct btrfs_lockdep_keyset *ks;
182 
183 	BUG_ON(level >= ARRAY_SIZE(ks->keys));
184 
185 	/* find the matching keyset, id 0 is the default entry */
186 	for (ks = btrfs_lockdep_keysets; ks->id; ks++)
187 		if (ks->id == objectid)
188 			break;
189 
190 	lockdep_set_class_and_name(&eb->lock,
191 				   &ks->keys[level], ks->names[level]);
192 }
193 
194 #endif
195 
196 /*
197  * extents on the btree inode are pretty simple, there's one extent
198  * that covers the entire device
199  */
200 static struct extent_map *btree_get_extent(struct inode *inode,
201 		struct page *page, size_t pg_offset, u64 start, u64 len,
202 		int create)
203 {
204 	struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
205 	struct extent_map *em;
206 	int ret;
207 
208 	read_lock(&em_tree->lock);
209 	em = lookup_extent_mapping(em_tree, start, len);
210 	if (em) {
211 		em->bdev =
212 			BTRFS_I(inode)->root->fs_info->fs_devices->latest_bdev;
213 		read_unlock(&em_tree->lock);
214 		goto out;
215 	}
216 	read_unlock(&em_tree->lock);
217 
218 	em = alloc_extent_map();
219 	if (!em) {
220 		em = ERR_PTR(-ENOMEM);
221 		goto out;
222 	}
223 	em->start = 0;
224 	em->len = (u64)-1;
225 	em->block_len = (u64)-1;
226 	em->block_start = 0;
227 	em->bdev = BTRFS_I(inode)->root->fs_info->fs_devices->latest_bdev;
228 
229 	write_lock(&em_tree->lock);
230 	ret = add_extent_mapping(em_tree, em, 0);
231 	if (ret == -EEXIST) {
232 		free_extent_map(em);
233 		em = lookup_extent_mapping(em_tree, start, len);
234 		if (!em)
235 			em = ERR_PTR(-EIO);
236 	} else if (ret) {
237 		free_extent_map(em);
238 		em = ERR_PTR(ret);
239 	}
240 	write_unlock(&em_tree->lock);
241 
242 out:
243 	return em;
244 }
245 
246 u32 btrfs_csum_data(char *data, u32 seed, size_t len)
247 {
248 	return btrfs_crc32c(seed, data, len);
249 }
250 
251 void btrfs_csum_final(u32 crc, char *result)
252 {
253 	put_unaligned_le32(~crc, result);
254 }
255 
256 /*
257  * compute the csum for a btree block, and either verify it or write it
258  * into the csum field of the block.
259  */
260 static int csum_tree_block(struct btrfs_root *root, struct extent_buffer *buf,
261 			   int verify)
262 {
263 	u16 csum_size = btrfs_super_csum_size(root->fs_info->super_copy);
264 	char *result = NULL;
265 	unsigned long len;
266 	unsigned long cur_len;
267 	unsigned long offset = BTRFS_CSUM_SIZE;
268 	char *kaddr;
269 	unsigned long map_start;
270 	unsigned long map_len;
271 	int err;
272 	u32 crc = ~(u32)0;
273 	unsigned long inline_result;
274 
275 	len = buf->len - offset;
276 	while (len > 0) {
277 		err = map_private_extent_buffer(buf, offset, 32,
278 					&kaddr, &map_start, &map_len);
279 		if (err)
280 			return 1;
281 		cur_len = min(len, map_len - (offset - map_start));
282 		crc = btrfs_csum_data(kaddr + offset - map_start,
283 				      crc, cur_len);
284 		len -= cur_len;
285 		offset += cur_len;
286 	}
287 	if (csum_size > sizeof(inline_result)) {
288 		result = kzalloc(csum_size * sizeof(char), GFP_NOFS);
289 		if (!result)
290 			return 1;
291 	} else {
292 		result = (char *)&inline_result;
293 	}
294 
295 	btrfs_csum_final(crc, result);
296 
297 	if (verify) {
298 		if (memcmp_extent_buffer(buf, result, 0, csum_size)) {
299 			u32 val;
300 			u32 found = 0;
301 			memcpy(&found, result, csum_size);
302 
303 			read_extent_buffer(buf, &val, 0, csum_size);
304 			printk_ratelimited(KERN_INFO
305 				"BTRFS: %s checksum verify failed on %llu wanted %X found %X "
306 				"level %d\n",
307 				root->fs_info->sb->s_id, buf->start,
308 				val, found, btrfs_header_level(buf));
309 			if (result != (char *)&inline_result)
310 				kfree(result);
311 			return 1;
312 		}
313 	} else {
314 		write_extent_buffer(buf, result, 0, csum_size);
315 	}
316 	if (result != (char *)&inline_result)
317 		kfree(result);
318 	return 0;
319 }
320 
321 /*
322  * we can't consider a given block up to date unless the transid of the
323  * block matches the transid in the parent node's pointer.  This is how we
324  * detect blocks that either didn't get written at all or got written
325  * in the wrong place.
326  */
327 static int verify_parent_transid(struct extent_io_tree *io_tree,
328 				 struct extent_buffer *eb, u64 parent_transid,
329 				 int atomic)
330 {
331 	struct extent_state *cached_state = NULL;
332 	int ret;
333 	bool need_lock = (current->journal_info ==
334 			  (void *)BTRFS_SEND_TRANS_STUB);
335 
336 	if (!parent_transid || btrfs_header_generation(eb) == parent_transid)
337 		return 0;
338 
339 	if (atomic)
340 		return -EAGAIN;
341 
342 	if (need_lock) {
343 		btrfs_tree_read_lock(eb);
344 		btrfs_set_lock_blocking_rw(eb, BTRFS_READ_LOCK);
345 	}
346 
347 	lock_extent_bits(io_tree, eb->start, eb->start + eb->len - 1,
348 			 0, &cached_state);
349 	if (extent_buffer_uptodate(eb) &&
350 	    btrfs_header_generation(eb) == parent_transid) {
351 		ret = 0;
352 		goto out;
353 	}
354 	printk_ratelimited("parent transid verify failed on %llu wanted %llu "
355 		       "found %llu\n",
356 		       eb->start, parent_transid, btrfs_header_generation(eb));
357 	ret = 1;
358 
359 	/*
360 	 * Things reading via commit roots that don't have normal protection,
361 	 * like send, can have a really old block in cache that may point at a
362 	 * block that has been free'd and re-allocated.  So don't clear uptodate
363 	 * if we find an eb that is under IO (dirty/writeback) because we could
364 	 * end up reading in the stale data and then writing it back out and
365 	 * making everybody very sad.
366 	 */
367 	if (!extent_buffer_under_io(eb))
368 		clear_extent_buffer_uptodate(eb);
369 out:
370 	unlock_extent_cached(io_tree, eb->start, eb->start + eb->len - 1,
371 			     &cached_state, GFP_NOFS);
372 	if (need_lock)
373 		btrfs_tree_read_unlock_blocking(eb);
374 	return ret;
375 }
376 
377 /*
378  * Return 0 if the superblock checksum type matches the checksum value of that
379  * algorithm. Pass the raw disk superblock data.
380  */
381 static int btrfs_check_super_csum(char *raw_disk_sb)
382 {
383 	struct btrfs_super_block *disk_sb =
384 		(struct btrfs_super_block *)raw_disk_sb;
385 	u16 csum_type = btrfs_super_csum_type(disk_sb);
386 	int ret = 0;
387 
388 	if (csum_type == BTRFS_CSUM_TYPE_CRC32) {
389 		u32 crc = ~(u32)0;
390 		const int csum_size = sizeof(crc);
391 		char result[csum_size];
392 
393 		/*
394 		 * The super_block structure does not span the whole
395 		 * BTRFS_SUPER_INFO_SIZE range, we expect that the unused space
396 		 * is filled with zeros and is included in the checkum.
397 		 */
398 		crc = btrfs_csum_data(raw_disk_sb + BTRFS_CSUM_SIZE,
399 				crc, BTRFS_SUPER_INFO_SIZE - BTRFS_CSUM_SIZE);
400 		btrfs_csum_final(crc, result);
401 
402 		if (memcmp(raw_disk_sb, result, csum_size))
403 			ret = 1;
404 
405 		if (ret && btrfs_super_generation(disk_sb) < 10) {
406 			printk(KERN_WARNING
407 				"BTRFS: super block crcs don't match, older mkfs detected\n");
408 			ret = 0;
409 		}
410 	}
411 
412 	if (csum_type >= ARRAY_SIZE(btrfs_csum_sizes)) {
413 		printk(KERN_ERR "BTRFS: unsupported checksum algorithm %u\n",
414 				csum_type);
415 		ret = 1;
416 	}
417 
418 	return ret;
419 }
420 
421 /*
422  * helper to read a given tree block, doing retries as required when
423  * the checksums don't match and we have alternate mirrors to try.
424  */
425 static int btree_read_extent_buffer_pages(struct btrfs_root *root,
426 					  struct extent_buffer *eb,
427 					  u64 start, u64 parent_transid)
428 {
429 	struct extent_io_tree *io_tree;
430 	int failed = 0;
431 	int ret;
432 	int num_copies = 0;
433 	int mirror_num = 0;
434 	int failed_mirror = 0;
435 
436 	clear_bit(EXTENT_BUFFER_CORRUPT, &eb->bflags);
437 	io_tree = &BTRFS_I(root->fs_info->btree_inode)->io_tree;
438 	while (1) {
439 		ret = read_extent_buffer_pages(io_tree, eb, start,
440 					       WAIT_COMPLETE,
441 					       btree_get_extent, mirror_num);
442 		if (!ret) {
443 			if (!verify_parent_transid(io_tree, eb,
444 						   parent_transid, 0))
445 				break;
446 			else
447 				ret = -EIO;
448 		}
449 
450 		/*
451 		 * This buffer's crc is fine, but its contents are corrupted, so
452 		 * there is no reason to read the other copies, they won't be
453 		 * any less wrong.
454 		 */
455 		if (test_bit(EXTENT_BUFFER_CORRUPT, &eb->bflags))
456 			break;
457 
458 		num_copies = btrfs_num_copies(root->fs_info,
459 					      eb->start, eb->len);
460 		if (num_copies == 1)
461 			break;
462 
463 		if (!failed_mirror) {
464 			failed = 1;
465 			failed_mirror = eb->read_mirror;
466 		}
467 
468 		mirror_num++;
469 		if (mirror_num == failed_mirror)
470 			mirror_num++;
471 
472 		if (mirror_num > num_copies)
473 			break;
474 	}
475 
476 	if (failed && !ret && failed_mirror)
477 		repair_eb_io_failure(root, eb, failed_mirror);
478 
479 	return ret;
480 }
481 
482 /*
483  * checksum a dirty tree block before IO.  This has extra checks to make sure
484  * we only fill in the checksum field in the first page of a multi-page block
485  */
486 
487 static int csum_dirty_buffer(struct btrfs_root *root, struct page *page)
488 {
489 	u64 start = page_offset(page);
490 	u64 found_start;
491 	struct extent_buffer *eb;
492 
493 	eb = (struct extent_buffer *)page->private;
494 	if (page != eb->pages[0])
495 		return 0;
496 	found_start = btrfs_header_bytenr(eb);
497 	if (WARN_ON(found_start != start || !PageUptodate(page)))
498 		return 0;
499 	csum_tree_block(root, eb, 0);
500 	return 0;
501 }
502 
503 static int check_tree_block_fsid(struct btrfs_root *root,
504 				 struct extent_buffer *eb)
505 {
506 	struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices;
507 	u8 fsid[BTRFS_UUID_SIZE];
508 	int ret = 1;
509 
510 	read_extent_buffer(eb, fsid, btrfs_header_fsid(), BTRFS_FSID_SIZE);
511 	while (fs_devices) {
512 		if (!memcmp(fsid, fs_devices->fsid, BTRFS_FSID_SIZE)) {
513 			ret = 0;
514 			break;
515 		}
516 		fs_devices = fs_devices->seed;
517 	}
518 	return ret;
519 }
520 
521 #define CORRUPT(reason, eb, root, slot)				\
522 	btrfs_crit(root->fs_info, "corrupt leaf, %s: block=%llu,"	\
523 		   "root=%llu, slot=%d", reason,			\
524 	       btrfs_header_bytenr(eb),	root->objectid, slot)
525 
526 static noinline int check_leaf(struct btrfs_root *root,
527 			       struct extent_buffer *leaf)
528 {
529 	struct btrfs_key key;
530 	struct btrfs_key leaf_key;
531 	u32 nritems = btrfs_header_nritems(leaf);
532 	int slot;
533 
534 	if (nritems == 0)
535 		return 0;
536 
537 	/* Check the 0 item */
538 	if (btrfs_item_offset_nr(leaf, 0) + btrfs_item_size_nr(leaf, 0) !=
539 	    BTRFS_LEAF_DATA_SIZE(root)) {
540 		CORRUPT("invalid item offset size pair", leaf, root, 0);
541 		return -EIO;
542 	}
543 
544 	/*
545 	 * Check to make sure each items keys are in the correct order and their
546 	 * offsets make sense.  We only have to loop through nritems-1 because
547 	 * we check the current slot against the next slot, which verifies the
548 	 * next slot's offset+size makes sense and that the current's slot
549 	 * offset is correct.
550 	 */
551 	for (slot = 0; slot < nritems - 1; slot++) {
552 		btrfs_item_key_to_cpu(leaf, &leaf_key, slot);
553 		btrfs_item_key_to_cpu(leaf, &key, slot + 1);
554 
555 		/* Make sure the keys are in the right order */
556 		if (btrfs_comp_cpu_keys(&leaf_key, &key) >= 0) {
557 			CORRUPT("bad key order", leaf, root, slot);
558 			return -EIO;
559 		}
560 
561 		/*
562 		 * Make sure the offset and ends are right, remember that the
563 		 * item data starts at the end of the leaf and grows towards the
564 		 * front.
565 		 */
566 		if (btrfs_item_offset_nr(leaf, slot) !=
567 			btrfs_item_end_nr(leaf, slot + 1)) {
568 			CORRUPT("slot offset bad", leaf, root, slot);
569 			return -EIO;
570 		}
571 
572 		/*
573 		 * Check to make sure that we don't point outside of the leaf,
574 		 * just incase all the items are consistent to eachother, but
575 		 * all point outside of the leaf.
576 		 */
577 		if (btrfs_item_end_nr(leaf, slot) >
578 		    BTRFS_LEAF_DATA_SIZE(root)) {
579 			CORRUPT("slot end outside of leaf", leaf, root, slot);
580 			return -EIO;
581 		}
582 	}
583 
584 	return 0;
585 }
586 
587 static int btree_readpage_end_io_hook(struct btrfs_io_bio *io_bio,
588 				      u64 phy_offset, struct page *page,
589 				      u64 start, u64 end, int mirror)
590 {
591 	u64 found_start;
592 	int found_level;
593 	struct extent_buffer *eb;
594 	struct btrfs_root *root = BTRFS_I(page->mapping->host)->root;
595 	int ret = 0;
596 	int reads_done;
597 
598 	if (!page->private)
599 		goto out;
600 
601 	eb = (struct extent_buffer *)page->private;
602 
603 	/* the pending IO might have been the only thing that kept this buffer
604 	 * in memory.  Make sure we have a ref for all this other checks
605 	 */
606 	extent_buffer_get(eb);
607 
608 	reads_done = atomic_dec_and_test(&eb->io_pages);
609 	if (!reads_done)
610 		goto err;
611 
612 	eb->read_mirror = mirror;
613 	if (test_bit(EXTENT_BUFFER_IOERR, &eb->bflags)) {
614 		ret = -EIO;
615 		goto err;
616 	}
617 
618 	found_start = btrfs_header_bytenr(eb);
619 	if (found_start != eb->start) {
620 		printk_ratelimited(KERN_INFO "BTRFS: bad tree block start "
621 			       "%llu %llu\n",
622 			       found_start, eb->start);
623 		ret = -EIO;
624 		goto err;
625 	}
626 	if (check_tree_block_fsid(root, eb)) {
627 		printk_ratelimited(KERN_INFO "BTRFS: bad fsid on block %llu\n",
628 			       eb->start);
629 		ret = -EIO;
630 		goto err;
631 	}
632 	found_level = btrfs_header_level(eb);
633 	if (found_level >= BTRFS_MAX_LEVEL) {
634 		btrfs_info(root->fs_info, "bad tree block level %d",
635 			   (int)btrfs_header_level(eb));
636 		ret = -EIO;
637 		goto err;
638 	}
639 
640 	btrfs_set_buffer_lockdep_class(btrfs_header_owner(eb),
641 				       eb, found_level);
642 
643 	ret = csum_tree_block(root, eb, 1);
644 	if (ret) {
645 		ret = -EIO;
646 		goto err;
647 	}
648 
649 	/*
650 	 * If this is a leaf block and it is corrupt, set the corrupt bit so
651 	 * that we don't try and read the other copies of this block, just
652 	 * return -EIO.
653 	 */
654 	if (found_level == 0 && check_leaf(root, eb)) {
655 		set_bit(EXTENT_BUFFER_CORRUPT, &eb->bflags);
656 		ret = -EIO;
657 	}
658 
659 	if (!ret)
660 		set_extent_buffer_uptodate(eb);
661 err:
662 	if (reads_done &&
663 	    test_and_clear_bit(EXTENT_BUFFER_READAHEAD, &eb->bflags))
664 		btree_readahead_hook(root, eb, eb->start, ret);
665 
666 	if (ret) {
667 		/*
668 		 * our io error hook is going to dec the io pages
669 		 * again, we have to make sure it has something
670 		 * to decrement
671 		 */
672 		atomic_inc(&eb->io_pages);
673 		clear_extent_buffer_uptodate(eb);
674 	}
675 	free_extent_buffer(eb);
676 out:
677 	return ret;
678 }
679 
680 static int btree_io_failed_hook(struct page *page, int failed_mirror)
681 {
682 	struct extent_buffer *eb;
683 	struct btrfs_root *root = BTRFS_I(page->mapping->host)->root;
684 
685 	eb = (struct extent_buffer *)page->private;
686 	set_bit(EXTENT_BUFFER_IOERR, &eb->bflags);
687 	eb->read_mirror = failed_mirror;
688 	atomic_dec(&eb->io_pages);
689 	if (test_and_clear_bit(EXTENT_BUFFER_READAHEAD, &eb->bflags))
690 		btree_readahead_hook(root, eb, eb->start, -EIO);
691 	return -EIO;	/* we fixed nothing */
692 }
693 
694 static void end_workqueue_bio(struct bio *bio, int err)
695 {
696 	struct end_io_wq *end_io_wq = bio->bi_private;
697 	struct btrfs_fs_info *fs_info;
698 
699 	fs_info = end_io_wq->info;
700 	end_io_wq->error = err;
701 	btrfs_init_work(&end_io_wq->work, end_workqueue_fn, NULL, NULL);
702 
703 	if (bio->bi_rw & REQ_WRITE) {
704 		if (end_io_wq->metadata == BTRFS_WQ_ENDIO_METADATA)
705 			btrfs_queue_work(fs_info->endio_meta_write_workers,
706 					 &end_io_wq->work);
707 		else if (end_io_wq->metadata == BTRFS_WQ_ENDIO_FREE_SPACE)
708 			btrfs_queue_work(fs_info->endio_freespace_worker,
709 					 &end_io_wq->work);
710 		else if (end_io_wq->metadata == BTRFS_WQ_ENDIO_RAID56)
711 			btrfs_queue_work(fs_info->endio_raid56_workers,
712 					 &end_io_wq->work);
713 		else
714 			btrfs_queue_work(fs_info->endio_write_workers,
715 					 &end_io_wq->work);
716 	} else {
717 		if (end_io_wq->metadata == BTRFS_WQ_ENDIO_RAID56)
718 			btrfs_queue_work(fs_info->endio_raid56_workers,
719 					 &end_io_wq->work);
720 		else if (end_io_wq->metadata)
721 			btrfs_queue_work(fs_info->endio_meta_workers,
722 					 &end_io_wq->work);
723 		else
724 			btrfs_queue_work(fs_info->endio_workers,
725 					 &end_io_wq->work);
726 	}
727 }
728 
729 /*
730  * For the metadata arg you want
731  *
732  * 0 - if data
733  * 1 - if normal metadta
734  * 2 - if writing to the free space cache area
735  * 3 - raid parity work
736  */
737 int btrfs_bio_wq_end_io(struct btrfs_fs_info *info, struct bio *bio,
738 			int metadata)
739 {
740 	struct end_io_wq *end_io_wq;
741 	end_io_wq = kmalloc(sizeof(*end_io_wq), GFP_NOFS);
742 	if (!end_io_wq)
743 		return -ENOMEM;
744 
745 	end_io_wq->private = bio->bi_private;
746 	end_io_wq->end_io = bio->bi_end_io;
747 	end_io_wq->info = info;
748 	end_io_wq->error = 0;
749 	end_io_wq->bio = bio;
750 	end_io_wq->metadata = metadata;
751 
752 	bio->bi_private = end_io_wq;
753 	bio->bi_end_io = end_workqueue_bio;
754 	return 0;
755 }
756 
757 unsigned long btrfs_async_submit_limit(struct btrfs_fs_info *info)
758 {
759 	unsigned long limit = min_t(unsigned long,
760 				    info->thread_pool_size,
761 				    info->fs_devices->open_devices);
762 	return 256 * limit;
763 }
764 
765 static void run_one_async_start(struct btrfs_work *work)
766 {
767 	struct async_submit_bio *async;
768 	int ret;
769 
770 	async = container_of(work, struct  async_submit_bio, work);
771 	ret = async->submit_bio_start(async->inode, async->rw, async->bio,
772 				      async->mirror_num, async->bio_flags,
773 				      async->bio_offset);
774 	if (ret)
775 		async->error = ret;
776 }
777 
778 static void run_one_async_done(struct btrfs_work *work)
779 {
780 	struct btrfs_fs_info *fs_info;
781 	struct async_submit_bio *async;
782 	int limit;
783 
784 	async = container_of(work, struct  async_submit_bio, work);
785 	fs_info = BTRFS_I(async->inode)->root->fs_info;
786 
787 	limit = btrfs_async_submit_limit(fs_info);
788 	limit = limit * 2 / 3;
789 
790 	if (atomic_dec_return(&fs_info->nr_async_submits) < limit &&
791 	    waitqueue_active(&fs_info->async_submit_wait))
792 		wake_up(&fs_info->async_submit_wait);
793 
794 	/* If an error occured we just want to clean up the bio and move on */
795 	if (async->error) {
796 		bio_endio(async->bio, async->error);
797 		return;
798 	}
799 
800 	async->submit_bio_done(async->inode, async->rw, async->bio,
801 			       async->mirror_num, async->bio_flags,
802 			       async->bio_offset);
803 }
804 
805 static void run_one_async_free(struct btrfs_work *work)
806 {
807 	struct async_submit_bio *async;
808 
809 	async = container_of(work, struct  async_submit_bio, work);
810 	kfree(async);
811 }
812 
813 int btrfs_wq_submit_bio(struct btrfs_fs_info *fs_info, struct inode *inode,
814 			int rw, struct bio *bio, int mirror_num,
815 			unsigned long bio_flags,
816 			u64 bio_offset,
817 			extent_submit_bio_hook_t *submit_bio_start,
818 			extent_submit_bio_hook_t *submit_bio_done)
819 {
820 	struct async_submit_bio *async;
821 
822 	async = kmalloc(sizeof(*async), GFP_NOFS);
823 	if (!async)
824 		return -ENOMEM;
825 
826 	async->inode = inode;
827 	async->rw = rw;
828 	async->bio = bio;
829 	async->mirror_num = mirror_num;
830 	async->submit_bio_start = submit_bio_start;
831 	async->submit_bio_done = submit_bio_done;
832 
833 	btrfs_init_work(&async->work, run_one_async_start,
834 			run_one_async_done, run_one_async_free);
835 
836 	async->bio_flags = bio_flags;
837 	async->bio_offset = bio_offset;
838 
839 	async->error = 0;
840 
841 	atomic_inc(&fs_info->nr_async_submits);
842 
843 	if (rw & REQ_SYNC)
844 		btrfs_set_work_high_priority(&async->work);
845 
846 	btrfs_queue_work(fs_info->workers, &async->work);
847 
848 	while (atomic_read(&fs_info->async_submit_draining) &&
849 	      atomic_read(&fs_info->nr_async_submits)) {
850 		wait_event(fs_info->async_submit_wait,
851 			   (atomic_read(&fs_info->nr_async_submits) == 0));
852 	}
853 
854 	return 0;
855 }
856 
857 static int btree_csum_one_bio(struct bio *bio)
858 {
859 	struct bio_vec *bvec;
860 	struct btrfs_root *root;
861 	int i, ret = 0;
862 
863 	bio_for_each_segment_all(bvec, bio, i) {
864 		root = BTRFS_I(bvec->bv_page->mapping->host)->root;
865 		ret = csum_dirty_buffer(root, bvec->bv_page);
866 		if (ret)
867 			break;
868 	}
869 
870 	return ret;
871 }
872 
873 static int __btree_submit_bio_start(struct inode *inode, int rw,
874 				    struct bio *bio, int mirror_num,
875 				    unsigned long bio_flags,
876 				    u64 bio_offset)
877 {
878 	/*
879 	 * when we're called for a write, we're already in the async
880 	 * submission context.  Just jump into btrfs_map_bio
881 	 */
882 	return btree_csum_one_bio(bio);
883 }
884 
885 static int __btree_submit_bio_done(struct inode *inode, int rw, struct bio *bio,
886 				 int mirror_num, unsigned long bio_flags,
887 				 u64 bio_offset)
888 {
889 	int ret;
890 
891 	/*
892 	 * when we're called for a write, we're already in the async
893 	 * submission context.  Just jump into btrfs_map_bio
894 	 */
895 	ret = btrfs_map_bio(BTRFS_I(inode)->root, rw, bio, mirror_num, 1);
896 	if (ret)
897 		bio_endio(bio, ret);
898 	return ret;
899 }
900 
901 static int check_async_write(struct inode *inode, unsigned long bio_flags)
902 {
903 	if (bio_flags & EXTENT_BIO_TREE_LOG)
904 		return 0;
905 #ifdef CONFIG_X86
906 	if (cpu_has_xmm4_2)
907 		return 0;
908 #endif
909 	return 1;
910 }
911 
912 static int btree_submit_bio_hook(struct inode *inode, int rw, struct bio *bio,
913 				 int mirror_num, unsigned long bio_flags,
914 				 u64 bio_offset)
915 {
916 	int async = check_async_write(inode, bio_flags);
917 	int ret;
918 
919 	if (!(rw & REQ_WRITE)) {
920 		/*
921 		 * called for a read, do the setup so that checksum validation
922 		 * can happen in the async kernel threads
923 		 */
924 		ret = btrfs_bio_wq_end_io(BTRFS_I(inode)->root->fs_info,
925 					  bio, 1);
926 		if (ret)
927 			goto out_w_error;
928 		ret = btrfs_map_bio(BTRFS_I(inode)->root, rw, bio,
929 				    mirror_num, 0);
930 	} else if (!async) {
931 		ret = btree_csum_one_bio(bio);
932 		if (ret)
933 			goto out_w_error;
934 		ret = btrfs_map_bio(BTRFS_I(inode)->root, rw, bio,
935 				    mirror_num, 0);
936 	} else {
937 		/*
938 		 * kthread helpers are used to submit writes so that
939 		 * checksumming can happen in parallel across all CPUs
940 		 */
941 		ret = btrfs_wq_submit_bio(BTRFS_I(inode)->root->fs_info,
942 					  inode, rw, bio, mirror_num, 0,
943 					  bio_offset,
944 					  __btree_submit_bio_start,
945 					  __btree_submit_bio_done);
946 	}
947 
948 	if (ret) {
949 out_w_error:
950 		bio_endio(bio, ret);
951 	}
952 	return ret;
953 }
954 
955 #ifdef CONFIG_MIGRATION
956 static int btree_migratepage(struct address_space *mapping,
957 			struct page *newpage, struct page *page,
958 			enum migrate_mode mode)
959 {
960 	/*
961 	 * we can't safely write a btree page from here,
962 	 * we haven't done the locking hook
963 	 */
964 	if (PageDirty(page))
965 		return -EAGAIN;
966 	/*
967 	 * Buffers may be managed in a filesystem specific way.
968 	 * We must have no buffers or drop them.
969 	 */
970 	if (page_has_private(page) &&
971 	    !try_to_release_page(page, GFP_KERNEL))
972 		return -EAGAIN;
973 	return migrate_page(mapping, newpage, page, mode);
974 }
975 #endif
976 
977 
978 static int btree_writepages(struct address_space *mapping,
979 			    struct writeback_control *wbc)
980 {
981 	struct btrfs_fs_info *fs_info;
982 	int ret;
983 
984 	if (wbc->sync_mode == WB_SYNC_NONE) {
985 
986 		if (wbc->for_kupdate)
987 			return 0;
988 
989 		fs_info = BTRFS_I(mapping->host)->root->fs_info;
990 		/* this is a bit racy, but that's ok */
991 		ret = percpu_counter_compare(&fs_info->dirty_metadata_bytes,
992 					     BTRFS_DIRTY_METADATA_THRESH);
993 		if (ret < 0)
994 			return 0;
995 	}
996 	return btree_write_cache_pages(mapping, wbc);
997 }
998 
999 static int btree_readpage(struct file *file, struct page *page)
1000 {
1001 	struct extent_io_tree *tree;
1002 	tree = &BTRFS_I(page->mapping->host)->io_tree;
1003 	return extent_read_full_page(tree, page, btree_get_extent, 0);
1004 }
1005 
1006 static int btree_releasepage(struct page *page, gfp_t gfp_flags)
1007 {
1008 	if (PageWriteback(page) || PageDirty(page))
1009 		return 0;
1010 
1011 	return try_release_extent_buffer(page);
1012 }
1013 
1014 static void btree_invalidatepage(struct page *page, unsigned int offset,
1015 				 unsigned int length)
1016 {
1017 	struct extent_io_tree *tree;
1018 	tree = &BTRFS_I(page->mapping->host)->io_tree;
1019 	extent_invalidatepage(tree, page, offset);
1020 	btree_releasepage(page, GFP_NOFS);
1021 	if (PagePrivate(page)) {
1022 		btrfs_warn(BTRFS_I(page->mapping->host)->root->fs_info,
1023 			   "page private not zero on page %llu",
1024 			   (unsigned long long)page_offset(page));
1025 		ClearPagePrivate(page);
1026 		set_page_private(page, 0);
1027 		page_cache_release(page);
1028 	}
1029 }
1030 
1031 static int btree_set_page_dirty(struct page *page)
1032 {
1033 #ifdef DEBUG
1034 	struct extent_buffer *eb;
1035 
1036 	BUG_ON(!PagePrivate(page));
1037 	eb = (struct extent_buffer *)page->private;
1038 	BUG_ON(!eb);
1039 	BUG_ON(!test_bit(EXTENT_BUFFER_DIRTY, &eb->bflags));
1040 	BUG_ON(!atomic_read(&eb->refs));
1041 	btrfs_assert_tree_locked(eb);
1042 #endif
1043 	return __set_page_dirty_nobuffers(page);
1044 }
1045 
1046 static const struct address_space_operations btree_aops = {
1047 	.readpage	= btree_readpage,
1048 	.writepages	= btree_writepages,
1049 	.releasepage	= btree_releasepage,
1050 	.invalidatepage = btree_invalidatepage,
1051 #ifdef CONFIG_MIGRATION
1052 	.migratepage	= btree_migratepage,
1053 #endif
1054 	.set_page_dirty = btree_set_page_dirty,
1055 };
1056 
1057 int readahead_tree_block(struct btrfs_root *root, u64 bytenr, u32 blocksize,
1058 			 u64 parent_transid)
1059 {
1060 	struct extent_buffer *buf = NULL;
1061 	struct inode *btree_inode = root->fs_info->btree_inode;
1062 	int ret = 0;
1063 
1064 	buf = btrfs_find_create_tree_block(root, bytenr, blocksize);
1065 	if (!buf)
1066 		return 0;
1067 	read_extent_buffer_pages(&BTRFS_I(btree_inode)->io_tree,
1068 				 buf, 0, WAIT_NONE, btree_get_extent, 0);
1069 	free_extent_buffer(buf);
1070 	return ret;
1071 }
1072 
1073 int reada_tree_block_flagged(struct btrfs_root *root, u64 bytenr, u32 blocksize,
1074 			 int mirror_num, struct extent_buffer **eb)
1075 {
1076 	struct extent_buffer *buf = NULL;
1077 	struct inode *btree_inode = root->fs_info->btree_inode;
1078 	struct extent_io_tree *io_tree = &BTRFS_I(btree_inode)->io_tree;
1079 	int ret;
1080 
1081 	buf = btrfs_find_create_tree_block(root, bytenr, blocksize);
1082 	if (!buf)
1083 		return 0;
1084 
1085 	set_bit(EXTENT_BUFFER_READAHEAD, &buf->bflags);
1086 
1087 	ret = read_extent_buffer_pages(io_tree, buf, 0, WAIT_PAGE_LOCK,
1088 				       btree_get_extent, mirror_num);
1089 	if (ret) {
1090 		free_extent_buffer(buf);
1091 		return ret;
1092 	}
1093 
1094 	if (test_bit(EXTENT_BUFFER_CORRUPT, &buf->bflags)) {
1095 		free_extent_buffer(buf);
1096 		return -EIO;
1097 	} else if (extent_buffer_uptodate(buf)) {
1098 		*eb = buf;
1099 	} else {
1100 		free_extent_buffer(buf);
1101 	}
1102 	return 0;
1103 }
1104 
1105 struct extent_buffer *btrfs_find_tree_block(struct btrfs_root *root,
1106 					    u64 bytenr, u32 blocksize)
1107 {
1108 	return find_extent_buffer(root->fs_info, bytenr);
1109 }
1110 
1111 struct extent_buffer *btrfs_find_create_tree_block(struct btrfs_root *root,
1112 						 u64 bytenr, u32 blocksize)
1113 {
1114 #ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
1115 	if (unlikely(test_bit(BTRFS_ROOT_DUMMY_ROOT, &root->state)))
1116 		return alloc_test_extent_buffer(root->fs_info, bytenr,
1117 						blocksize);
1118 #endif
1119 	return alloc_extent_buffer(root->fs_info, bytenr, blocksize);
1120 }
1121 
1122 
1123 int btrfs_write_tree_block(struct extent_buffer *buf)
1124 {
1125 	return filemap_fdatawrite_range(buf->pages[0]->mapping, buf->start,
1126 					buf->start + buf->len - 1);
1127 }
1128 
1129 int btrfs_wait_tree_block_writeback(struct extent_buffer *buf)
1130 {
1131 	return filemap_fdatawait_range(buf->pages[0]->mapping,
1132 				       buf->start, buf->start + buf->len - 1);
1133 }
1134 
1135 struct extent_buffer *read_tree_block(struct btrfs_root *root, u64 bytenr,
1136 				      u32 blocksize, u64 parent_transid)
1137 {
1138 	struct extent_buffer *buf = NULL;
1139 	int ret;
1140 
1141 	buf = btrfs_find_create_tree_block(root, bytenr, blocksize);
1142 	if (!buf)
1143 		return NULL;
1144 
1145 	ret = btree_read_extent_buffer_pages(root, buf, 0, parent_transid);
1146 	if (ret) {
1147 		free_extent_buffer(buf);
1148 		return NULL;
1149 	}
1150 	return buf;
1151 
1152 }
1153 
1154 void clean_tree_block(struct btrfs_trans_handle *trans, struct btrfs_root *root,
1155 		      struct extent_buffer *buf)
1156 {
1157 	struct btrfs_fs_info *fs_info = root->fs_info;
1158 
1159 	if (btrfs_header_generation(buf) ==
1160 	    fs_info->running_transaction->transid) {
1161 		btrfs_assert_tree_locked(buf);
1162 
1163 		if (test_and_clear_bit(EXTENT_BUFFER_DIRTY, &buf->bflags)) {
1164 			__percpu_counter_add(&fs_info->dirty_metadata_bytes,
1165 					     -buf->len,
1166 					     fs_info->dirty_metadata_batch);
1167 			/* ugh, clear_extent_buffer_dirty needs to lock the page */
1168 			btrfs_set_lock_blocking(buf);
1169 			clear_extent_buffer_dirty(buf);
1170 		}
1171 	}
1172 }
1173 
1174 static struct btrfs_subvolume_writers *btrfs_alloc_subvolume_writers(void)
1175 {
1176 	struct btrfs_subvolume_writers *writers;
1177 	int ret;
1178 
1179 	writers = kmalloc(sizeof(*writers), GFP_NOFS);
1180 	if (!writers)
1181 		return ERR_PTR(-ENOMEM);
1182 
1183 	ret = percpu_counter_init(&writers->counter, 0);
1184 	if (ret < 0) {
1185 		kfree(writers);
1186 		return ERR_PTR(ret);
1187 	}
1188 
1189 	init_waitqueue_head(&writers->wait);
1190 	return writers;
1191 }
1192 
1193 static void
1194 btrfs_free_subvolume_writers(struct btrfs_subvolume_writers *writers)
1195 {
1196 	percpu_counter_destroy(&writers->counter);
1197 	kfree(writers);
1198 }
1199 
1200 static void __setup_root(u32 nodesize, u32 leafsize, u32 sectorsize,
1201 			 u32 stripesize, struct btrfs_root *root,
1202 			 struct btrfs_fs_info *fs_info,
1203 			 u64 objectid)
1204 {
1205 	root->node = NULL;
1206 	root->commit_root = NULL;
1207 	root->sectorsize = sectorsize;
1208 	root->nodesize = nodesize;
1209 	root->leafsize = leafsize;
1210 	root->stripesize = stripesize;
1211 	root->state = 0;
1212 	root->orphan_cleanup_state = 0;
1213 
1214 	root->objectid = objectid;
1215 	root->last_trans = 0;
1216 	root->highest_objectid = 0;
1217 	root->nr_delalloc_inodes = 0;
1218 	root->nr_ordered_extents = 0;
1219 	root->name = NULL;
1220 	root->inode_tree = RB_ROOT;
1221 	INIT_RADIX_TREE(&root->delayed_nodes_tree, GFP_ATOMIC);
1222 	root->block_rsv = NULL;
1223 	root->orphan_block_rsv = NULL;
1224 
1225 	INIT_LIST_HEAD(&root->dirty_list);
1226 	INIT_LIST_HEAD(&root->root_list);
1227 	INIT_LIST_HEAD(&root->delalloc_inodes);
1228 	INIT_LIST_HEAD(&root->delalloc_root);
1229 	INIT_LIST_HEAD(&root->ordered_extents);
1230 	INIT_LIST_HEAD(&root->ordered_root);
1231 	INIT_LIST_HEAD(&root->logged_list[0]);
1232 	INIT_LIST_HEAD(&root->logged_list[1]);
1233 	spin_lock_init(&root->orphan_lock);
1234 	spin_lock_init(&root->inode_lock);
1235 	spin_lock_init(&root->delalloc_lock);
1236 	spin_lock_init(&root->ordered_extent_lock);
1237 	spin_lock_init(&root->accounting_lock);
1238 	spin_lock_init(&root->log_extents_lock[0]);
1239 	spin_lock_init(&root->log_extents_lock[1]);
1240 	mutex_init(&root->objectid_mutex);
1241 	mutex_init(&root->log_mutex);
1242 	mutex_init(&root->ordered_extent_mutex);
1243 	mutex_init(&root->delalloc_mutex);
1244 	init_waitqueue_head(&root->log_writer_wait);
1245 	init_waitqueue_head(&root->log_commit_wait[0]);
1246 	init_waitqueue_head(&root->log_commit_wait[1]);
1247 	INIT_LIST_HEAD(&root->log_ctxs[0]);
1248 	INIT_LIST_HEAD(&root->log_ctxs[1]);
1249 	atomic_set(&root->log_commit[0], 0);
1250 	atomic_set(&root->log_commit[1], 0);
1251 	atomic_set(&root->log_writers, 0);
1252 	atomic_set(&root->log_batch, 0);
1253 	atomic_set(&root->orphan_inodes, 0);
1254 	atomic_set(&root->refs, 1);
1255 	atomic_set(&root->will_be_snapshoted, 0);
1256 	root->log_transid = 0;
1257 	root->log_transid_committed = -1;
1258 	root->last_log_commit = 0;
1259 	if (fs_info)
1260 		extent_io_tree_init(&root->dirty_log_pages,
1261 				     fs_info->btree_inode->i_mapping);
1262 
1263 	memset(&root->root_key, 0, sizeof(root->root_key));
1264 	memset(&root->root_item, 0, sizeof(root->root_item));
1265 	memset(&root->defrag_progress, 0, sizeof(root->defrag_progress));
1266 	memset(&root->root_kobj, 0, sizeof(root->root_kobj));
1267 	if (fs_info)
1268 		root->defrag_trans_start = fs_info->generation;
1269 	else
1270 		root->defrag_trans_start = 0;
1271 	init_completion(&root->kobj_unregister);
1272 	root->root_key.objectid = objectid;
1273 	root->anon_dev = 0;
1274 
1275 	spin_lock_init(&root->root_item_lock);
1276 }
1277 
1278 static struct btrfs_root *btrfs_alloc_root(struct btrfs_fs_info *fs_info)
1279 {
1280 	struct btrfs_root *root = kzalloc(sizeof(*root), GFP_NOFS);
1281 	if (root)
1282 		root->fs_info = fs_info;
1283 	return root;
1284 }
1285 
1286 #ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
1287 /* Should only be used by the testing infrastructure */
1288 struct btrfs_root *btrfs_alloc_dummy_root(void)
1289 {
1290 	struct btrfs_root *root;
1291 
1292 	root = btrfs_alloc_root(NULL);
1293 	if (!root)
1294 		return ERR_PTR(-ENOMEM);
1295 	__setup_root(4096, 4096, 4096, 4096, root, NULL, 1);
1296 	set_bit(BTRFS_ROOT_DUMMY_ROOT, &root->state);
1297 	root->alloc_bytenr = 0;
1298 
1299 	return root;
1300 }
1301 #endif
1302 
1303 struct btrfs_root *btrfs_create_tree(struct btrfs_trans_handle *trans,
1304 				     struct btrfs_fs_info *fs_info,
1305 				     u64 objectid)
1306 {
1307 	struct extent_buffer *leaf;
1308 	struct btrfs_root *tree_root = fs_info->tree_root;
1309 	struct btrfs_root *root;
1310 	struct btrfs_key key;
1311 	int ret = 0;
1312 	uuid_le uuid;
1313 
1314 	root = btrfs_alloc_root(fs_info);
1315 	if (!root)
1316 		return ERR_PTR(-ENOMEM);
1317 
1318 	__setup_root(tree_root->nodesize, tree_root->leafsize,
1319 		     tree_root->sectorsize, tree_root->stripesize,
1320 		     root, fs_info, objectid);
1321 	root->root_key.objectid = objectid;
1322 	root->root_key.type = BTRFS_ROOT_ITEM_KEY;
1323 	root->root_key.offset = 0;
1324 
1325 	leaf = btrfs_alloc_free_block(trans, root, root->leafsize,
1326 				      0, objectid, NULL, 0, 0, 0);
1327 	if (IS_ERR(leaf)) {
1328 		ret = PTR_ERR(leaf);
1329 		leaf = NULL;
1330 		goto fail;
1331 	}
1332 
1333 	memset_extent_buffer(leaf, 0, 0, sizeof(struct btrfs_header));
1334 	btrfs_set_header_bytenr(leaf, leaf->start);
1335 	btrfs_set_header_generation(leaf, trans->transid);
1336 	btrfs_set_header_backref_rev(leaf, BTRFS_MIXED_BACKREF_REV);
1337 	btrfs_set_header_owner(leaf, objectid);
1338 	root->node = leaf;
1339 
1340 	write_extent_buffer(leaf, fs_info->fsid, btrfs_header_fsid(),
1341 			    BTRFS_FSID_SIZE);
1342 	write_extent_buffer(leaf, fs_info->chunk_tree_uuid,
1343 			    btrfs_header_chunk_tree_uuid(leaf),
1344 			    BTRFS_UUID_SIZE);
1345 	btrfs_mark_buffer_dirty(leaf);
1346 
1347 	root->commit_root = btrfs_root_node(root);
1348 	set_bit(BTRFS_ROOT_TRACK_DIRTY, &root->state);
1349 
1350 	root->root_item.flags = 0;
1351 	root->root_item.byte_limit = 0;
1352 	btrfs_set_root_bytenr(&root->root_item, leaf->start);
1353 	btrfs_set_root_generation(&root->root_item, trans->transid);
1354 	btrfs_set_root_level(&root->root_item, 0);
1355 	btrfs_set_root_refs(&root->root_item, 1);
1356 	btrfs_set_root_used(&root->root_item, leaf->len);
1357 	btrfs_set_root_last_snapshot(&root->root_item, 0);
1358 	btrfs_set_root_dirid(&root->root_item, 0);
1359 	uuid_le_gen(&uuid);
1360 	memcpy(root->root_item.uuid, uuid.b, BTRFS_UUID_SIZE);
1361 	root->root_item.drop_level = 0;
1362 
1363 	key.objectid = objectid;
1364 	key.type = BTRFS_ROOT_ITEM_KEY;
1365 	key.offset = 0;
1366 	ret = btrfs_insert_root(trans, tree_root, &key, &root->root_item);
1367 	if (ret)
1368 		goto fail;
1369 
1370 	btrfs_tree_unlock(leaf);
1371 
1372 	return root;
1373 
1374 fail:
1375 	if (leaf) {
1376 		btrfs_tree_unlock(leaf);
1377 		free_extent_buffer(root->commit_root);
1378 		free_extent_buffer(leaf);
1379 	}
1380 	kfree(root);
1381 
1382 	return ERR_PTR(ret);
1383 }
1384 
1385 static struct btrfs_root *alloc_log_tree(struct btrfs_trans_handle *trans,
1386 					 struct btrfs_fs_info *fs_info)
1387 {
1388 	struct btrfs_root *root;
1389 	struct btrfs_root *tree_root = fs_info->tree_root;
1390 	struct extent_buffer *leaf;
1391 
1392 	root = btrfs_alloc_root(fs_info);
1393 	if (!root)
1394 		return ERR_PTR(-ENOMEM);
1395 
1396 	__setup_root(tree_root->nodesize, tree_root->leafsize,
1397 		     tree_root->sectorsize, tree_root->stripesize,
1398 		     root, fs_info, BTRFS_TREE_LOG_OBJECTID);
1399 
1400 	root->root_key.objectid = BTRFS_TREE_LOG_OBJECTID;
1401 	root->root_key.type = BTRFS_ROOT_ITEM_KEY;
1402 	root->root_key.offset = BTRFS_TREE_LOG_OBJECTID;
1403 
1404 	/*
1405 	 * DON'T set REF_COWS for log trees
1406 	 *
1407 	 * log trees do not get reference counted because they go away
1408 	 * before a real commit is actually done.  They do store pointers
1409 	 * to file data extents, and those reference counts still get
1410 	 * updated (along with back refs to the log tree).
1411 	 */
1412 
1413 	leaf = btrfs_alloc_free_block(trans, root, root->leafsize, 0,
1414 				      BTRFS_TREE_LOG_OBJECTID, NULL,
1415 				      0, 0, 0);
1416 	if (IS_ERR(leaf)) {
1417 		kfree(root);
1418 		return ERR_CAST(leaf);
1419 	}
1420 
1421 	memset_extent_buffer(leaf, 0, 0, sizeof(struct btrfs_header));
1422 	btrfs_set_header_bytenr(leaf, leaf->start);
1423 	btrfs_set_header_generation(leaf, trans->transid);
1424 	btrfs_set_header_backref_rev(leaf, BTRFS_MIXED_BACKREF_REV);
1425 	btrfs_set_header_owner(leaf, BTRFS_TREE_LOG_OBJECTID);
1426 	root->node = leaf;
1427 
1428 	write_extent_buffer(root->node, root->fs_info->fsid,
1429 			    btrfs_header_fsid(), BTRFS_FSID_SIZE);
1430 	btrfs_mark_buffer_dirty(root->node);
1431 	btrfs_tree_unlock(root->node);
1432 	return root;
1433 }
1434 
1435 int btrfs_init_log_root_tree(struct btrfs_trans_handle *trans,
1436 			     struct btrfs_fs_info *fs_info)
1437 {
1438 	struct btrfs_root *log_root;
1439 
1440 	log_root = alloc_log_tree(trans, fs_info);
1441 	if (IS_ERR(log_root))
1442 		return PTR_ERR(log_root);
1443 	WARN_ON(fs_info->log_root_tree);
1444 	fs_info->log_root_tree = log_root;
1445 	return 0;
1446 }
1447 
1448 int btrfs_add_log_tree(struct btrfs_trans_handle *trans,
1449 		       struct btrfs_root *root)
1450 {
1451 	struct btrfs_root *log_root;
1452 	struct btrfs_inode_item *inode_item;
1453 
1454 	log_root = alloc_log_tree(trans, root->fs_info);
1455 	if (IS_ERR(log_root))
1456 		return PTR_ERR(log_root);
1457 
1458 	log_root->last_trans = trans->transid;
1459 	log_root->root_key.offset = root->root_key.objectid;
1460 
1461 	inode_item = &log_root->root_item.inode;
1462 	btrfs_set_stack_inode_generation(inode_item, 1);
1463 	btrfs_set_stack_inode_size(inode_item, 3);
1464 	btrfs_set_stack_inode_nlink(inode_item, 1);
1465 	btrfs_set_stack_inode_nbytes(inode_item, root->leafsize);
1466 	btrfs_set_stack_inode_mode(inode_item, S_IFDIR | 0755);
1467 
1468 	btrfs_set_root_node(&log_root->root_item, log_root->node);
1469 
1470 	WARN_ON(root->log_root);
1471 	root->log_root = log_root;
1472 	root->log_transid = 0;
1473 	root->log_transid_committed = -1;
1474 	root->last_log_commit = 0;
1475 	return 0;
1476 }
1477 
1478 static struct btrfs_root *btrfs_read_tree_root(struct btrfs_root *tree_root,
1479 					       struct btrfs_key *key)
1480 {
1481 	struct btrfs_root *root;
1482 	struct btrfs_fs_info *fs_info = tree_root->fs_info;
1483 	struct btrfs_path *path;
1484 	u64 generation;
1485 	u32 blocksize;
1486 	int ret;
1487 
1488 	path = btrfs_alloc_path();
1489 	if (!path)
1490 		return ERR_PTR(-ENOMEM);
1491 
1492 	root = btrfs_alloc_root(fs_info);
1493 	if (!root) {
1494 		ret = -ENOMEM;
1495 		goto alloc_fail;
1496 	}
1497 
1498 	__setup_root(tree_root->nodesize, tree_root->leafsize,
1499 		     tree_root->sectorsize, tree_root->stripesize,
1500 		     root, fs_info, key->objectid);
1501 
1502 	ret = btrfs_find_root(tree_root, key, path,
1503 			      &root->root_item, &root->root_key);
1504 	if (ret) {
1505 		if (ret > 0)
1506 			ret = -ENOENT;
1507 		goto find_fail;
1508 	}
1509 
1510 	generation = btrfs_root_generation(&root->root_item);
1511 	blocksize = btrfs_level_size(root, btrfs_root_level(&root->root_item));
1512 	root->node = read_tree_block(root, btrfs_root_bytenr(&root->root_item),
1513 				     blocksize, generation);
1514 	if (!root->node) {
1515 		ret = -ENOMEM;
1516 		goto find_fail;
1517 	} else if (!btrfs_buffer_uptodate(root->node, generation, 0)) {
1518 		ret = -EIO;
1519 		goto read_fail;
1520 	}
1521 	root->commit_root = btrfs_root_node(root);
1522 out:
1523 	btrfs_free_path(path);
1524 	return root;
1525 
1526 read_fail:
1527 	free_extent_buffer(root->node);
1528 find_fail:
1529 	kfree(root);
1530 alloc_fail:
1531 	root = ERR_PTR(ret);
1532 	goto out;
1533 }
1534 
1535 struct btrfs_root *btrfs_read_fs_root(struct btrfs_root *tree_root,
1536 				      struct btrfs_key *location)
1537 {
1538 	struct btrfs_root *root;
1539 
1540 	root = btrfs_read_tree_root(tree_root, location);
1541 	if (IS_ERR(root))
1542 		return root;
1543 
1544 	if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID) {
1545 		set_bit(BTRFS_ROOT_REF_COWS, &root->state);
1546 		btrfs_check_and_init_root_item(&root->root_item);
1547 	}
1548 
1549 	return root;
1550 }
1551 
1552 int btrfs_init_fs_root(struct btrfs_root *root)
1553 {
1554 	int ret;
1555 	struct btrfs_subvolume_writers *writers;
1556 
1557 	root->free_ino_ctl = kzalloc(sizeof(*root->free_ino_ctl), GFP_NOFS);
1558 	root->free_ino_pinned = kzalloc(sizeof(*root->free_ino_pinned),
1559 					GFP_NOFS);
1560 	if (!root->free_ino_pinned || !root->free_ino_ctl) {
1561 		ret = -ENOMEM;
1562 		goto fail;
1563 	}
1564 
1565 	writers = btrfs_alloc_subvolume_writers();
1566 	if (IS_ERR(writers)) {
1567 		ret = PTR_ERR(writers);
1568 		goto fail;
1569 	}
1570 	root->subv_writers = writers;
1571 
1572 	btrfs_init_free_ino_ctl(root);
1573 	spin_lock_init(&root->cache_lock);
1574 	init_waitqueue_head(&root->cache_wait);
1575 
1576 	ret = get_anon_bdev(&root->anon_dev);
1577 	if (ret)
1578 		goto free_writers;
1579 	return 0;
1580 
1581 free_writers:
1582 	btrfs_free_subvolume_writers(root->subv_writers);
1583 fail:
1584 	kfree(root->free_ino_ctl);
1585 	kfree(root->free_ino_pinned);
1586 	return ret;
1587 }
1588 
1589 static struct btrfs_root *btrfs_lookup_fs_root(struct btrfs_fs_info *fs_info,
1590 					       u64 root_id)
1591 {
1592 	struct btrfs_root *root;
1593 
1594 	spin_lock(&fs_info->fs_roots_radix_lock);
1595 	root = radix_tree_lookup(&fs_info->fs_roots_radix,
1596 				 (unsigned long)root_id);
1597 	spin_unlock(&fs_info->fs_roots_radix_lock);
1598 	return root;
1599 }
1600 
1601 int btrfs_insert_fs_root(struct btrfs_fs_info *fs_info,
1602 			 struct btrfs_root *root)
1603 {
1604 	int ret;
1605 
1606 	ret = radix_tree_preload(GFP_NOFS & ~__GFP_HIGHMEM);
1607 	if (ret)
1608 		return ret;
1609 
1610 	spin_lock(&fs_info->fs_roots_radix_lock);
1611 	ret = radix_tree_insert(&fs_info->fs_roots_radix,
1612 				(unsigned long)root->root_key.objectid,
1613 				root);
1614 	if (ret == 0)
1615 		set_bit(BTRFS_ROOT_IN_RADIX, &root->state);
1616 	spin_unlock(&fs_info->fs_roots_radix_lock);
1617 	radix_tree_preload_end();
1618 
1619 	return ret;
1620 }
1621 
1622 struct btrfs_root *btrfs_get_fs_root(struct btrfs_fs_info *fs_info,
1623 				     struct btrfs_key *location,
1624 				     bool check_ref)
1625 {
1626 	struct btrfs_root *root;
1627 	int ret;
1628 
1629 	if (location->objectid == BTRFS_ROOT_TREE_OBJECTID)
1630 		return fs_info->tree_root;
1631 	if (location->objectid == BTRFS_EXTENT_TREE_OBJECTID)
1632 		return fs_info->extent_root;
1633 	if (location->objectid == BTRFS_CHUNK_TREE_OBJECTID)
1634 		return fs_info->chunk_root;
1635 	if (location->objectid == BTRFS_DEV_TREE_OBJECTID)
1636 		return fs_info->dev_root;
1637 	if (location->objectid == BTRFS_CSUM_TREE_OBJECTID)
1638 		return fs_info->csum_root;
1639 	if (location->objectid == BTRFS_QUOTA_TREE_OBJECTID)
1640 		return fs_info->quota_root ? fs_info->quota_root :
1641 					     ERR_PTR(-ENOENT);
1642 	if (location->objectid == BTRFS_UUID_TREE_OBJECTID)
1643 		return fs_info->uuid_root ? fs_info->uuid_root :
1644 					    ERR_PTR(-ENOENT);
1645 again:
1646 	root = btrfs_lookup_fs_root(fs_info, location->objectid);
1647 	if (root) {
1648 		if (check_ref && btrfs_root_refs(&root->root_item) == 0)
1649 			return ERR_PTR(-ENOENT);
1650 		return root;
1651 	}
1652 
1653 	root = btrfs_read_fs_root(fs_info->tree_root, location);
1654 	if (IS_ERR(root))
1655 		return root;
1656 
1657 	if (check_ref && btrfs_root_refs(&root->root_item) == 0) {
1658 		ret = -ENOENT;
1659 		goto fail;
1660 	}
1661 
1662 	ret = btrfs_init_fs_root(root);
1663 	if (ret)
1664 		goto fail;
1665 
1666 	ret = btrfs_find_item(fs_info->tree_root, NULL, BTRFS_ORPHAN_OBJECTID,
1667 			location->objectid, BTRFS_ORPHAN_ITEM_KEY, NULL);
1668 	if (ret < 0)
1669 		goto fail;
1670 	if (ret == 0)
1671 		set_bit(BTRFS_ROOT_ORPHAN_ITEM_INSERTED, &root->state);
1672 
1673 	ret = btrfs_insert_fs_root(fs_info, root);
1674 	if (ret) {
1675 		if (ret == -EEXIST) {
1676 			free_fs_root(root);
1677 			goto again;
1678 		}
1679 		goto fail;
1680 	}
1681 	return root;
1682 fail:
1683 	free_fs_root(root);
1684 	return ERR_PTR(ret);
1685 }
1686 
1687 static int btrfs_congested_fn(void *congested_data, int bdi_bits)
1688 {
1689 	struct btrfs_fs_info *info = (struct btrfs_fs_info *)congested_data;
1690 	int ret = 0;
1691 	struct btrfs_device *device;
1692 	struct backing_dev_info *bdi;
1693 
1694 	rcu_read_lock();
1695 	list_for_each_entry_rcu(device, &info->fs_devices->devices, dev_list) {
1696 		if (!device->bdev)
1697 			continue;
1698 		bdi = blk_get_backing_dev_info(device->bdev);
1699 		if (bdi && bdi_congested(bdi, bdi_bits)) {
1700 			ret = 1;
1701 			break;
1702 		}
1703 	}
1704 	rcu_read_unlock();
1705 	return ret;
1706 }
1707 
1708 /*
1709  * If this fails, caller must call bdi_destroy() to get rid of the
1710  * bdi again.
1711  */
1712 static int setup_bdi(struct btrfs_fs_info *info, struct backing_dev_info *bdi)
1713 {
1714 	int err;
1715 
1716 	bdi->capabilities = BDI_CAP_MAP_COPY;
1717 	err = bdi_setup_and_register(bdi, "btrfs", BDI_CAP_MAP_COPY);
1718 	if (err)
1719 		return err;
1720 
1721 	bdi->ra_pages	= default_backing_dev_info.ra_pages;
1722 	bdi->congested_fn	= btrfs_congested_fn;
1723 	bdi->congested_data	= info;
1724 	return 0;
1725 }
1726 
1727 /*
1728  * called by the kthread helper functions to finally call the bio end_io
1729  * functions.  This is where read checksum verification actually happens
1730  */
1731 static void end_workqueue_fn(struct btrfs_work *work)
1732 {
1733 	struct bio *bio;
1734 	struct end_io_wq *end_io_wq;
1735 	int error;
1736 
1737 	end_io_wq = container_of(work, struct end_io_wq, work);
1738 	bio = end_io_wq->bio;
1739 
1740 	error = end_io_wq->error;
1741 	bio->bi_private = end_io_wq->private;
1742 	bio->bi_end_io = end_io_wq->end_io;
1743 	kfree(end_io_wq);
1744 	bio_endio_nodec(bio, error);
1745 }
1746 
1747 static int cleaner_kthread(void *arg)
1748 {
1749 	struct btrfs_root *root = arg;
1750 	int again;
1751 
1752 	do {
1753 		again = 0;
1754 
1755 		/* Make the cleaner go to sleep early. */
1756 		if (btrfs_need_cleaner_sleep(root))
1757 			goto sleep;
1758 
1759 		if (!mutex_trylock(&root->fs_info->cleaner_mutex))
1760 			goto sleep;
1761 
1762 		/*
1763 		 * Avoid the problem that we change the status of the fs
1764 		 * during the above check and trylock.
1765 		 */
1766 		if (btrfs_need_cleaner_sleep(root)) {
1767 			mutex_unlock(&root->fs_info->cleaner_mutex);
1768 			goto sleep;
1769 		}
1770 
1771 		btrfs_run_delayed_iputs(root);
1772 		again = btrfs_clean_one_deleted_snapshot(root);
1773 		mutex_unlock(&root->fs_info->cleaner_mutex);
1774 
1775 		/*
1776 		 * The defragger has dealt with the R/O remount and umount,
1777 		 * needn't do anything special here.
1778 		 */
1779 		btrfs_run_defrag_inodes(root->fs_info);
1780 sleep:
1781 		if (!try_to_freeze() && !again) {
1782 			set_current_state(TASK_INTERRUPTIBLE);
1783 			if (!kthread_should_stop())
1784 				schedule();
1785 			__set_current_state(TASK_RUNNING);
1786 		}
1787 	} while (!kthread_should_stop());
1788 	return 0;
1789 }
1790 
1791 static int transaction_kthread(void *arg)
1792 {
1793 	struct btrfs_root *root = arg;
1794 	struct btrfs_trans_handle *trans;
1795 	struct btrfs_transaction *cur;
1796 	u64 transid;
1797 	unsigned long now;
1798 	unsigned long delay;
1799 	bool cannot_commit;
1800 
1801 	do {
1802 		cannot_commit = false;
1803 		delay = HZ * root->fs_info->commit_interval;
1804 		mutex_lock(&root->fs_info->transaction_kthread_mutex);
1805 
1806 		spin_lock(&root->fs_info->trans_lock);
1807 		cur = root->fs_info->running_transaction;
1808 		if (!cur) {
1809 			spin_unlock(&root->fs_info->trans_lock);
1810 			goto sleep;
1811 		}
1812 
1813 		now = get_seconds();
1814 		if (cur->state < TRANS_STATE_BLOCKED &&
1815 		    (now < cur->start_time ||
1816 		     now - cur->start_time < root->fs_info->commit_interval)) {
1817 			spin_unlock(&root->fs_info->trans_lock);
1818 			delay = HZ * 5;
1819 			goto sleep;
1820 		}
1821 		transid = cur->transid;
1822 		spin_unlock(&root->fs_info->trans_lock);
1823 
1824 		/* If the file system is aborted, this will always fail. */
1825 		trans = btrfs_attach_transaction(root);
1826 		if (IS_ERR(trans)) {
1827 			if (PTR_ERR(trans) != -ENOENT)
1828 				cannot_commit = true;
1829 			goto sleep;
1830 		}
1831 		if (transid == trans->transid) {
1832 			btrfs_commit_transaction(trans, root);
1833 		} else {
1834 			btrfs_end_transaction(trans, root);
1835 		}
1836 sleep:
1837 		wake_up_process(root->fs_info->cleaner_kthread);
1838 		mutex_unlock(&root->fs_info->transaction_kthread_mutex);
1839 
1840 		if (unlikely(test_bit(BTRFS_FS_STATE_ERROR,
1841 				      &root->fs_info->fs_state)))
1842 			btrfs_cleanup_transaction(root);
1843 		if (!try_to_freeze()) {
1844 			set_current_state(TASK_INTERRUPTIBLE);
1845 			if (!kthread_should_stop() &&
1846 			    (!btrfs_transaction_blocked(root->fs_info) ||
1847 			     cannot_commit))
1848 				schedule_timeout(delay);
1849 			__set_current_state(TASK_RUNNING);
1850 		}
1851 	} while (!kthread_should_stop());
1852 	return 0;
1853 }
1854 
1855 /*
1856  * this will find the highest generation in the array of
1857  * root backups.  The index of the highest array is returned,
1858  * or -1 if we can't find anything.
1859  *
1860  * We check to make sure the array is valid by comparing the
1861  * generation of the latest  root in the array with the generation
1862  * in the super block.  If they don't match we pitch it.
1863  */
1864 static int find_newest_super_backup(struct btrfs_fs_info *info, u64 newest_gen)
1865 {
1866 	u64 cur;
1867 	int newest_index = -1;
1868 	struct btrfs_root_backup *root_backup;
1869 	int i;
1870 
1871 	for (i = 0; i < BTRFS_NUM_BACKUP_ROOTS; i++) {
1872 		root_backup = info->super_copy->super_roots + i;
1873 		cur = btrfs_backup_tree_root_gen(root_backup);
1874 		if (cur == newest_gen)
1875 			newest_index = i;
1876 	}
1877 
1878 	/* check to see if we actually wrapped around */
1879 	if (newest_index == BTRFS_NUM_BACKUP_ROOTS - 1) {
1880 		root_backup = info->super_copy->super_roots;
1881 		cur = btrfs_backup_tree_root_gen(root_backup);
1882 		if (cur == newest_gen)
1883 			newest_index = 0;
1884 	}
1885 	return newest_index;
1886 }
1887 
1888 
1889 /*
1890  * find the oldest backup so we know where to store new entries
1891  * in the backup array.  This will set the backup_root_index
1892  * field in the fs_info struct
1893  */
1894 static void find_oldest_super_backup(struct btrfs_fs_info *info,
1895 				     u64 newest_gen)
1896 {
1897 	int newest_index = -1;
1898 
1899 	newest_index = find_newest_super_backup(info, newest_gen);
1900 	/* if there was garbage in there, just move along */
1901 	if (newest_index == -1) {
1902 		info->backup_root_index = 0;
1903 	} else {
1904 		info->backup_root_index = (newest_index + 1) % BTRFS_NUM_BACKUP_ROOTS;
1905 	}
1906 }
1907 
1908 /*
1909  * copy all the root pointers into the super backup array.
1910  * this will bump the backup pointer by one when it is
1911  * done
1912  */
1913 static void backup_super_roots(struct btrfs_fs_info *info)
1914 {
1915 	int next_backup;
1916 	struct btrfs_root_backup *root_backup;
1917 	int last_backup;
1918 
1919 	next_backup = info->backup_root_index;
1920 	last_backup = (next_backup + BTRFS_NUM_BACKUP_ROOTS - 1) %
1921 		BTRFS_NUM_BACKUP_ROOTS;
1922 
1923 	/*
1924 	 * just overwrite the last backup if we're at the same generation
1925 	 * this happens only at umount
1926 	 */
1927 	root_backup = info->super_for_commit->super_roots + last_backup;
1928 	if (btrfs_backup_tree_root_gen(root_backup) ==
1929 	    btrfs_header_generation(info->tree_root->node))
1930 		next_backup = last_backup;
1931 
1932 	root_backup = info->super_for_commit->super_roots + next_backup;
1933 
1934 	/*
1935 	 * make sure all of our padding and empty slots get zero filled
1936 	 * regardless of which ones we use today
1937 	 */
1938 	memset(root_backup, 0, sizeof(*root_backup));
1939 
1940 	info->backup_root_index = (next_backup + 1) % BTRFS_NUM_BACKUP_ROOTS;
1941 
1942 	btrfs_set_backup_tree_root(root_backup, info->tree_root->node->start);
1943 	btrfs_set_backup_tree_root_gen(root_backup,
1944 			       btrfs_header_generation(info->tree_root->node));
1945 
1946 	btrfs_set_backup_tree_root_level(root_backup,
1947 			       btrfs_header_level(info->tree_root->node));
1948 
1949 	btrfs_set_backup_chunk_root(root_backup, info->chunk_root->node->start);
1950 	btrfs_set_backup_chunk_root_gen(root_backup,
1951 			       btrfs_header_generation(info->chunk_root->node));
1952 	btrfs_set_backup_chunk_root_level(root_backup,
1953 			       btrfs_header_level(info->chunk_root->node));
1954 
1955 	btrfs_set_backup_extent_root(root_backup, info->extent_root->node->start);
1956 	btrfs_set_backup_extent_root_gen(root_backup,
1957 			       btrfs_header_generation(info->extent_root->node));
1958 	btrfs_set_backup_extent_root_level(root_backup,
1959 			       btrfs_header_level(info->extent_root->node));
1960 
1961 	/*
1962 	 * we might commit during log recovery, which happens before we set
1963 	 * the fs_root.  Make sure it is valid before we fill it in.
1964 	 */
1965 	if (info->fs_root && info->fs_root->node) {
1966 		btrfs_set_backup_fs_root(root_backup,
1967 					 info->fs_root->node->start);
1968 		btrfs_set_backup_fs_root_gen(root_backup,
1969 			       btrfs_header_generation(info->fs_root->node));
1970 		btrfs_set_backup_fs_root_level(root_backup,
1971 			       btrfs_header_level(info->fs_root->node));
1972 	}
1973 
1974 	btrfs_set_backup_dev_root(root_backup, info->dev_root->node->start);
1975 	btrfs_set_backup_dev_root_gen(root_backup,
1976 			       btrfs_header_generation(info->dev_root->node));
1977 	btrfs_set_backup_dev_root_level(root_backup,
1978 				       btrfs_header_level(info->dev_root->node));
1979 
1980 	btrfs_set_backup_csum_root(root_backup, info->csum_root->node->start);
1981 	btrfs_set_backup_csum_root_gen(root_backup,
1982 			       btrfs_header_generation(info->csum_root->node));
1983 	btrfs_set_backup_csum_root_level(root_backup,
1984 			       btrfs_header_level(info->csum_root->node));
1985 
1986 	btrfs_set_backup_total_bytes(root_backup,
1987 			     btrfs_super_total_bytes(info->super_copy));
1988 	btrfs_set_backup_bytes_used(root_backup,
1989 			     btrfs_super_bytes_used(info->super_copy));
1990 	btrfs_set_backup_num_devices(root_backup,
1991 			     btrfs_super_num_devices(info->super_copy));
1992 
1993 	/*
1994 	 * if we don't copy this out to the super_copy, it won't get remembered
1995 	 * for the next commit
1996 	 */
1997 	memcpy(&info->super_copy->super_roots,
1998 	       &info->super_for_commit->super_roots,
1999 	       sizeof(*root_backup) * BTRFS_NUM_BACKUP_ROOTS);
2000 }
2001 
2002 /*
2003  * this copies info out of the root backup array and back into
2004  * the in-memory super block.  It is meant to help iterate through
2005  * the array, so you send it the number of backups you've already
2006  * tried and the last backup index you used.
2007  *
2008  * this returns -1 when it has tried all the backups
2009  */
2010 static noinline int next_root_backup(struct btrfs_fs_info *info,
2011 				     struct btrfs_super_block *super,
2012 				     int *num_backups_tried, int *backup_index)
2013 {
2014 	struct btrfs_root_backup *root_backup;
2015 	int newest = *backup_index;
2016 
2017 	if (*num_backups_tried == 0) {
2018 		u64 gen = btrfs_super_generation(super);
2019 
2020 		newest = find_newest_super_backup(info, gen);
2021 		if (newest == -1)
2022 			return -1;
2023 
2024 		*backup_index = newest;
2025 		*num_backups_tried = 1;
2026 	} else if (*num_backups_tried == BTRFS_NUM_BACKUP_ROOTS) {
2027 		/* we've tried all the backups, all done */
2028 		return -1;
2029 	} else {
2030 		/* jump to the next oldest backup */
2031 		newest = (*backup_index + BTRFS_NUM_BACKUP_ROOTS - 1) %
2032 			BTRFS_NUM_BACKUP_ROOTS;
2033 		*backup_index = newest;
2034 		*num_backups_tried += 1;
2035 	}
2036 	root_backup = super->super_roots + newest;
2037 
2038 	btrfs_set_super_generation(super,
2039 				   btrfs_backup_tree_root_gen(root_backup));
2040 	btrfs_set_super_root(super, btrfs_backup_tree_root(root_backup));
2041 	btrfs_set_super_root_level(super,
2042 				   btrfs_backup_tree_root_level(root_backup));
2043 	btrfs_set_super_bytes_used(super, btrfs_backup_bytes_used(root_backup));
2044 
2045 	/*
2046 	 * fixme: the total bytes and num_devices need to match or we should
2047 	 * need a fsck
2048 	 */
2049 	btrfs_set_super_total_bytes(super, btrfs_backup_total_bytes(root_backup));
2050 	btrfs_set_super_num_devices(super, btrfs_backup_num_devices(root_backup));
2051 	return 0;
2052 }
2053 
2054 /* helper to cleanup workers */
2055 static void btrfs_stop_all_workers(struct btrfs_fs_info *fs_info)
2056 {
2057 	btrfs_destroy_workqueue(fs_info->fixup_workers);
2058 	btrfs_destroy_workqueue(fs_info->delalloc_workers);
2059 	btrfs_destroy_workqueue(fs_info->workers);
2060 	btrfs_destroy_workqueue(fs_info->endio_workers);
2061 	btrfs_destroy_workqueue(fs_info->endio_meta_workers);
2062 	btrfs_destroy_workqueue(fs_info->endio_raid56_workers);
2063 	btrfs_destroy_workqueue(fs_info->rmw_workers);
2064 	btrfs_destroy_workqueue(fs_info->endio_meta_write_workers);
2065 	btrfs_destroy_workqueue(fs_info->endio_write_workers);
2066 	btrfs_destroy_workqueue(fs_info->endio_freespace_worker);
2067 	btrfs_destroy_workqueue(fs_info->submit_workers);
2068 	btrfs_destroy_workqueue(fs_info->delayed_workers);
2069 	btrfs_destroy_workqueue(fs_info->caching_workers);
2070 	btrfs_destroy_workqueue(fs_info->readahead_workers);
2071 	btrfs_destroy_workqueue(fs_info->flush_workers);
2072 	btrfs_destroy_workqueue(fs_info->qgroup_rescan_workers);
2073 	btrfs_destroy_workqueue(fs_info->extent_workers);
2074 }
2075 
2076 static void free_root_extent_buffers(struct btrfs_root *root)
2077 {
2078 	if (root) {
2079 		free_extent_buffer(root->node);
2080 		free_extent_buffer(root->commit_root);
2081 		root->node = NULL;
2082 		root->commit_root = NULL;
2083 	}
2084 }
2085 
2086 /* helper to cleanup tree roots */
2087 static void free_root_pointers(struct btrfs_fs_info *info, int chunk_root)
2088 {
2089 	free_root_extent_buffers(info->tree_root);
2090 
2091 	free_root_extent_buffers(info->dev_root);
2092 	free_root_extent_buffers(info->extent_root);
2093 	free_root_extent_buffers(info->csum_root);
2094 	free_root_extent_buffers(info->quota_root);
2095 	free_root_extent_buffers(info->uuid_root);
2096 	if (chunk_root)
2097 		free_root_extent_buffers(info->chunk_root);
2098 }
2099 
2100 void btrfs_free_fs_roots(struct btrfs_fs_info *fs_info)
2101 {
2102 	int ret;
2103 	struct btrfs_root *gang[8];
2104 	int i;
2105 
2106 	while (!list_empty(&fs_info->dead_roots)) {
2107 		gang[0] = list_entry(fs_info->dead_roots.next,
2108 				     struct btrfs_root, root_list);
2109 		list_del(&gang[0]->root_list);
2110 
2111 		if (test_bit(BTRFS_ROOT_IN_RADIX, &gang[0]->state)) {
2112 			btrfs_drop_and_free_fs_root(fs_info, gang[0]);
2113 		} else {
2114 			free_extent_buffer(gang[0]->node);
2115 			free_extent_buffer(gang[0]->commit_root);
2116 			btrfs_put_fs_root(gang[0]);
2117 		}
2118 	}
2119 
2120 	while (1) {
2121 		ret = radix_tree_gang_lookup(&fs_info->fs_roots_radix,
2122 					     (void **)gang, 0,
2123 					     ARRAY_SIZE(gang));
2124 		if (!ret)
2125 			break;
2126 		for (i = 0; i < ret; i++)
2127 			btrfs_drop_and_free_fs_root(fs_info, gang[i]);
2128 	}
2129 
2130 	if (test_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state)) {
2131 		btrfs_free_log_root_tree(NULL, fs_info);
2132 		btrfs_destroy_pinned_extent(fs_info->tree_root,
2133 					    fs_info->pinned_extents);
2134 	}
2135 }
2136 
2137 int open_ctree(struct super_block *sb,
2138 	       struct btrfs_fs_devices *fs_devices,
2139 	       char *options)
2140 {
2141 	u32 sectorsize;
2142 	u32 nodesize;
2143 	u32 leafsize;
2144 	u32 blocksize;
2145 	u32 stripesize;
2146 	u64 generation;
2147 	u64 features;
2148 	struct btrfs_key location;
2149 	struct buffer_head *bh;
2150 	struct btrfs_super_block *disk_super;
2151 	struct btrfs_fs_info *fs_info = btrfs_sb(sb);
2152 	struct btrfs_root *tree_root;
2153 	struct btrfs_root *extent_root;
2154 	struct btrfs_root *csum_root;
2155 	struct btrfs_root *chunk_root;
2156 	struct btrfs_root *dev_root;
2157 	struct btrfs_root *quota_root;
2158 	struct btrfs_root *uuid_root;
2159 	struct btrfs_root *log_tree_root;
2160 	int ret;
2161 	int err = -EINVAL;
2162 	int num_backups_tried = 0;
2163 	int backup_index = 0;
2164 	int max_active;
2165 	int flags = WQ_MEM_RECLAIM | WQ_FREEZABLE | WQ_UNBOUND;
2166 	bool create_uuid_tree;
2167 	bool check_uuid_tree;
2168 
2169 	tree_root = fs_info->tree_root = btrfs_alloc_root(fs_info);
2170 	chunk_root = fs_info->chunk_root = btrfs_alloc_root(fs_info);
2171 	if (!tree_root || !chunk_root) {
2172 		err = -ENOMEM;
2173 		goto fail;
2174 	}
2175 
2176 	ret = init_srcu_struct(&fs_info->subvol_srcu);
2177 	if (ret) {
2178 		err = ret;
2179 		goto fail;
2180 	}
2181 
2182 	ret = setup_bdi(fs_info, &fs_info->bdi);
2183 	if (ret) {
2184 		err = ret;
2185 		goto fail_srcu;
2186 	}
2187 
2188 	ret = percpu_counter_init(&fs_info->dirty_metadata_bytes, 0);
2189 	if (ret) {
2190 		err = ret;
2191 		goto fail_bdi;
2192 	}
2193 	fs_info->dirty_metadata_batch = PAGE_CACHE_SIZE *
2194 					(1 + ilog2(nr_cpu_ids));
2195 
2196 	ret = percpu_counter_init(&fs_info->delalloc_bytes, 0);
2197 	if (ret) {
2198 		err = ret;
2199 		goto fail_dirty_metadata_bytes;
2200 	}
2201 
2202 	ret = percpu_counter_init(&fs_info->bio_counter, 0);
2203 	if (ret) {
2204 		err = ret;
2205 		goto fail_delalloc_bytes;
2206 	}
2207 
2208 	fs_info->btree_inode = new_inode(sb);
2209 	if (!fs_info->btree_inode) {
2210 		err = -ENOMEM;
2211 		goto fail_bio_counter;
2212 	}
2213 
2214 	mapping_set_gfp_mask(fs_info->btree_inode->i_mapping, GFP_NOFS);
2215 
2216 	INIT_RADIX_TREE(&fs_info->fs_roots_radix, GFP_ATOMIC);
2217 	INIT_RADIX_TREE(&fs_info->buffer_radix, GFP_ATOMIC);
2218 	INIT_LIST_HEAD(&fs_info->trans_list);
2219 	INIT_LIST_HEAD(&fs_info->dead_roots);
2220 	INIT_LIST_HEAD(&fs_info->delayed_iputs);
2221 	INIT_LIST_HEAD(&fs_info->delalloc_roots);
2222 	INIT_LIST_HEAD(&fs_info->caching_block_groups);
2223 	spin_lock_init(&fs_info->delalloc_root_lock);
2224 	spin_lock_init(&fs_info->trans_lock);
2225 	spin_lock_init(&fs_info->fs_roots_radix_lock);
2226 	spin_lock_init(&fs_info->delayed_iput_lock);
2227 	spin_lock_init(&fs_info->defrag_inodes_lock);
2228 	spin_lock_init(&fs_info->free_chunk_lock);
2229 	spin_lock_init(&fs_info->tree_mod_seq_lock);
2230 	spin_lock_init(&fs_info->super_lock);
2231 	spin_lock_init(&fs_info->qgroup_op_lock);
2232 	spin_lock_init(&fs_info->buffer_lock);
2233 	rwlock_init(&fs_info->tree_mod_log_lock);
2234 	mutex_init(&fs_info->reloc_mutex);
2235 	mutex_init(&fs_info->delalloc_root_mutex);
2236 	seqlock_init(&fs_info->profiles_lock);
2237 
2238 	init_completion(&fs_info->kobj_unregister);
2239 	INIT_LIST_HEAD(&fs_info->dirty_cowonly_roots);
2240 	INIT_LIST_HEAD(&fs_info->space_info);
2241 	INIT_LIST_HEAD(&fs_info->tree_mod_seq_list);
2242 	btrfs_mapping_init(&fs_info->mapping_tree);
2243 	btrfs_init_block_rsv(&fs_info->global_block_rsv,
2244 			     BTRFS_BLOCK_RSV_GLOBAL);
2245 	btrfs_init_block_rsv(&fs_info->delalloc_block_rsv,
2246 			     BTRFS_BLOCK_RSV_DELALLOC);
2247 	btrfs_init_block_rsv(&fs_info->trans_block_rsv, BTRFS_BLOCK_RSV_TRANS);
2248 	btrfs_init_block_rsv(&fs_info->chunk_block_rsv, BTRFS_BLOCK_RSV_CHUNK);
2249 	btrfs_init_block_rsv(&fs_info->empty_block_rsv, BTRFS_BLOCK_RSV_EMPTY);
2250 	btrfs_init_block_rsv(&fs_info->delayed_block_rsv,
2251 			     BTRFS_BLOCK_RSV_DELOPS);
2252 	atomic_set(&fs_info->nr_async_submits, 0);
2253 	atomic_set(&fs_info->async_delalloc_pages, 0);
2254 	atomic_set(&fs_info->async_submit_draining, 0);
2255 	atomic_set(&fs_info->nr_async_bios, 0);
2256 	atomic_set(&fs_info->defrag_running, 0);
2257 	atomic_set(&fs_info->qgroup_op_seq, 0);
2258 	atomic64_set(&fs_info->tree_mod_seq, 0);
2259 	fs_info->sb = sb;
2260 	fs_info->max_inline = 8192 * 1024;
2261 	fs_info->metadata_ratio = 0;
2262 	fs_info->defrag_inodes = RB_ROOT;
2263 	fs_info->free_chunk_space = 0;
2264 	fs_info->tree_mod_log = RB_ROOT;
2265 	fs_info->commit_interval = BTRFS_DEFAULT_COMMIT_INTERVAL;
2266 	fs_info->avg_delayed_ref_runtime = div64_u64(NSEC_PER_SEC, 64);
2267 	/* readahead state */
2268 	INIT_RADIX_TREE(&fs_info->reada_tree, GFP_NOFS & ~__GFP_WAIT);
2269 	spin_lock_init(&fs_info->reada_lock);
2270 
2271 	fs_info->thread_pool_size = min_t(unsigned long,
2272 					  num_online_cpus() + 2, 8);
2273 
2274 	INIT_LIST_HEAD(&fs_info->ordered_roots);
2275 	spin_lock_init(&fs_info->ordered_root_lock);
2276 	fs_info->delayed_root = kmalloc(sizeof(struct btrfs_delayed_root),
2277 					GFP_NOFS);
2278 	if (!fs_info->delayed_root) {
2279 		err = -ENOMEM;
2280 		goto fail_iput;
2281 	}
2282 	btrfs_init_delayed_root(fs_info->delayed_root);
2283 
2284 	mutex_init(&fs_info->scrub_lock);
2285 	atomic_set(&fs_info->scrubs_running, 0);
2286 	atomic_set(&fs_info->scrub_pause_req, 0);
2287 	atomic_set(&fs_info->scrubs_paused, 0);
2288 	atomic_set(&fs_info->scrub_cancel_req, 0);
2289 	init_waitqueue_head(&fs_info->replace_wait);
2290 	init_waitqueue_head(&fs_info->scrub_pause_wait);
2291 	fs_info->scrub_workers_refcnt = 0;
2292 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
2293 	fs_info->check_integrity_print_mask = 0;
2294 #endif
2295 
2296 	spin_lock_init(&fs_info->balance_lock);
2297 	mutex_init(&fs_info->balance_mutex);
2298 	atomic_set(&fs_info->balance_running, 0);
2299 	atomic_set(&fs_info->balance_pause_req, 0);
2300 	atomic_set(&fs_info->balance_cancel_req, 0);
2301 	fs_info->balance_ctl = NULL;
2302 	init_waitqueue_head(&fs_info->balance_wait_q);
2303 	btrfs_init_async_reclaim_work(&fs_info->async_reclaim_work);
2304 
2305 	sb->s_blocksize = 4096;
2306 	sb->s_blocksize_bits = blksize_bits(4096);
2307 	sb->s_bdi = &fs_info->bdi;
2308 
2309 	fs_info->btree_inode->i_ino = BTRFS_BTREE_INODE_OBJECTID;
2310 	set_nlink(fs_info->btree_inode, 1);
2311 	/*
2312 	 * we set the i_size on the btree inode to the max possible int.
2313 	 * the real end of the address space is determined by all of
2314 	 * the devices in the system
2315 	 */
2316 	fs_info->btree_inode->i_size = OFFSET_MAX;
2317 	fs_info->btree_inode->i_mapping->a_ops = &btree_aops;
2318 	fs_info->btree_inode->i_mapping->backing_dev_info = &fs_info->bdi;
2319 
2320 	RB_CLEAR_NODE(&BTRFS_I(fs_info->btree_inode)->rb_node);
2321 	extent_io_tree_init(&BTRFS_I(fs_info->btree_inode)->io_tree,
2322 			     fs_info->btree_inode->i_mapping);
2323 	BTRFS_I(fs_info->btree_inode)->io_tree.track_uptodate = 0;
2324 	extent_map_tree_init(&BTRFS_I(fs_info->btree_inode)->extent_tree);
2325 
2326 	BTRFS_I(fs_info->btree_inode)->io_tree.ops = &btree_extent_io_ops;
2327 
2328 	BTRFS_I(fs_info->btree_inode)->root = tree_root;
2329 	memset(&BTRFS_I(fs_info->btree_inode)->location, 0,
2330 	       sizeof(struct btrfs_key));
2331 	set_bit(BTRFS_INODE_DUMMY,
2332 		&BTRFS_I(fs_info->btree_inode)->runtime_flags);
2333 	btrfs_insert_inode_hash(fs_info->btree_inode);
2334 
2335 	spin_lock_init(&fs_info->block_group_cache_lock);
2336 	fs_info->block_group_cache_tree = RB_ROOT;
2337 	fs_info->first_logical_byte = (u64)-1;
2338 
2339 	extent_io_tree_init(&fs_info->freed_extents[0],
2340 			     fs_info->btree_inode->i_mapping);
2341 	extent_io_tree_init(&fs_info->freed_extents[1],
2342 			     fs_info->btree_inode->i_mapping);
2343 	fs_info->pinned_extents = &fs_info->freed_extents[0];
2344 	fs_info->do_barriers = 1;
2345 
2346 
2347 	mutex_init(&fs_info->ordered_operations_mutex);
2348 	mutex_init(&fs_info->ordered_extent_flush_mutex);
2349 	mutex_init(&fs_info->tree_log_mutex);
2350 	mutex_init(&fs_info->chunk_mutex);
2351 	mutex_init(&fs_info->transaction_kthread_mutex);
2352 	mutex_init(&fs_info->cleaner_mutex);
2353 	mutex_init(&fs_info->volume_mutex);
2354 	init_rwsem(&fs_info->commit_root_sem);
2355 	init_rwsem(&fs_info->cleanup_work_sem);
2356 	init_rwsem(&fs_info->subvol_sem);
2357 	sema_init(&fs_info->uuid_tree_rescan_sem, 1);
2358 	fs_info->dev_replace.lock_owner = 0;
2359 	atomic_set(&fs_info->dev_replace.nesting_level, 0);
2360 	mutex_init(&fs_info->dev_replace.lock_finishing_cancel_unmount);
2361 	mutex_init(&fs_info->dev_replace.lock_management_lock);
2362 	mutex_init(&fs_info->dev_replace.lock);
2363 
2364 	spin_lock_init(&fs_info->qgroup_lock);
2365 	mutex_init(&fs_info->qgroup_ioctl_lock);
2366 	fs_info->qgroup_tree = RB_ROOT;
2367 	fs_info->qgroup_op_tree = RB_ROOT;
2368 	INIT_LIST_HEAD(&fs_info->dirty_qgroups);
2369 	fs_info->qgroup_seq = 1;
2370 	fs_info->quota_enabled = 0;
2371 	fs_info->pending_quota_state = 0;
2372 	fs_info->qgroup_ulist = NULL;
2373 	mutex_init(&fs_info->qgroup_rescan_lock);
2374 
2375 	btrfs_init_free_cluster(&fs_info->meta_alloc_cluster);
2376 	btrfs_init_free_cluster(&fs_info->data_alloc_cluster);
2377 
2378 	init_waitqueue_head(&fs_info->transaction_throttle);
2379 	init_waitqueue_head(&fs_info->transaction_wait);
2380 	init_waitqueue_head(&fs_info->transaction_blocked_wait);
2381 	init_waitqueue_head(&fs_info->async_submit_wait);
2382 
2383 	ret = btrfs_alloc_stripe_hash_table(fs_info);
2384 	if (ret) {
2385 		err = ret;
2386 		goto fail_alloc;
2387 	}
2388 
2389 	__setup_root(4096, 4096, 4096, 4096, tree_root,
2390 		     fs_info, BTRFS_ROOT_TREE_OBJECTID);
2391 
2392 	invalidate_bdev(fs_devices->latest_bdev);
2393 
2394 	/*
2395 	 * Read super block and check the signature bytes only
2396 	 */
2397 	bh = btrfs_read_dev_super(fs_devices->latest_bdev);
2398 	if (!bh) {
2399 		err = -EINVAL;
2400 		goto fail_alloc;
2401 	}
2402 
2403 	/*
2404 	 * We want to check superblock checksum, the type is stored inside.
2405 	 * Pass the whole disk block of size BTRFS_SUPER_INFO_SIZE (4k).
2406 	 */
2407 	if (btrfs_check_super_csum(bh->b_data)) {
2408 		printk(KERN_ERR "BTRFS: superblock checksum mismatch\n");
2409 		err = -EINVAL;
2410 		goto fail_alloc;
2411 	}
2412 
2413 	/*
2414 	 * super_copy is zeroed at allocation time and we never touch the
2415 	 * following bytes up to INFO_SIZE, the checksum is calculated from
2416 	 * the whole block of INFO_SIZE
2417 	 */
2418 	memcpy(fs_info->super_copy, bh->b_data, sizeof(*fs_info->super_copy));
2419 	memcpy(fs_info->super_for_commit, fs_info->super_copy,
2420 	       sizeof(*fs_info->super_for_commit));
2421 	brelse(bh);
2422 
2423 	memcpy(fs_info->fsid, fs_info->super_copy->fsid, BTRFS_FSID_SIZE);
2424 
2425 	ret = btrfs_check_super_valid(fs_info, sb->s_flags & MS_RDONLY);
2426 	if (ret) {
2427 		printk(KERN_ERR "BTRFS: superblock contains fatal errors\n");
2428 		err = -EINVAL;
2429 		goto fail_alloc;
2430 	}
2431 
2432 	disk_super = fs_info->super_copy;
2433 	if (!btrfs_super_root(disk_super))
2434 		goto fail_alloc;
2435 
2436 	/* check FS state, whether FS is broken. */
2437 	if (btrfs_super_flags(disk_super) & BTRFS_SUPER_FLAG_ERROR)
2438 		set_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state);
2439 
2440 	/*
2441 	 * run through our array of backup supers and setup
2442 	 * our ring pointer to the oldest one
2443 	 */
2444 	generation = btrfs_super_generation(disk_super);
2445 	find_oldest_super_backup(fs_info, generation);
2446 
2447 	/*
2448 	 * In the long term, we'll store the compression type in the super
2449 	 * block, and it'll be used for per file compression control.
2450 	 */
2451 	fs_info->compress_type = BTRFS_COMPRESS_ZLIB;
2452 
2453 	ret = btrfs_parse_options(tree_root, options);
2454 	if (ret) {
2455 		err = ret;
2456 		goto fail_alloc;
2457 	}
2458 
2459 	features = btrfs_super_incompat_flags(disk_super) &
2460 		~BTRFS_FEATURE_INCOMPAT_SUPP;
2461 	if (features) {
2462 		printk(KERN_ERR "BTRFS: couldn't mount because of "
2463 		       "unsupported optional features (%Lx).\n",
2464 		       features);
2465 		err = -EINVAL;
2466 		goto fail_alloc;
2467 	}
2468 
2469 	if (btrfs_super_leafsize(disk_super) !=
2470 	    btrfs_super_nodesize(disk_super)) {
2471 		printk(KERN_ERR "BTRFS: couldn't mount because metadata "
2472 		       "blocksizes don't match.  node %d leaf %d\n",
2473 		       btrfs_super_nodesize(disk_super),
2474 		       btrfs_super_leafsize(disk_super));
2475 		err = -EINVAL;
2476 		goto fail_alloc;
2477 	}
2478 	if (btrfs_super_leafsize(disk_super) > BTRFS_MAX_METADATA_BLOCKSIZE) {
2479 		printk(KERN_ERR "BTRFS: couldn't mount because metadata "
2480 		       "blocksize (%d) was too large\n",
2481 		       btrfs_super_leafsize(disk_super));
2482 		err = -EINVAL;
2483 		goto fail_alloc;
2484 	}
2485 
2486 	features = btrfs_super_incompat_flags(disk_super);
2487 	features |= BTRFS_FEATURE_INCOMPAT_MIXED_BACKREF;
2488 	if (tree_root->fs_info->compress_type == BTRFS_COMPRESS_LZO)
2489 		features |= BTRFS_FEATURE_INCOMPAT_COMPRESS_LZO;
2490 
2491 	if (features & BTRFS_FEATURE_INCOMPAT_SKINNY_METADATA)
2492 		printk(KERN_ERR "BTRFS: has skinny extents\n");
2493 
2494 	/*
2495 	 * flag our filesystem as having big metadata blocks if
2496 	 * they are bigger than the page size
2497 	 */
2498 	if (btrfs_super_leafsize(disk_super) > PAGE_CACHE_SIZE) {
2499 		if (!(features & BTRFS_FEATURE_INCOMPAT_BIG_METADATA))
2500 			printk(KERN_INFO "BTRFS: flagging fs with big metadata feature\n");
2501 		features |= BTRFS_FEATURE_INCOMPAT_BIG_METADATA;
2502 	}
2503 
2504 	nodesize = btrfs_super_nodesize(disk_super);
2505 	leafsize = btrfs_super_leafsize(disk_super);
2506 	sectorsize = btrfs_super_sectorsize(disk_super);
2507 	stripesize = btrfs_super_stripesize(disk_super);
2508 	fs_info->dirty_metadata_batch = leafsize * (1 + ilog2(nr_cpu_ids));
2509 	fs_info->delalloc_batch = sectorsize * 512 * (1 + ilog2(nr_cpu_ids));
2510 
2511 	/*
2512 	 * mixed block groups end up with duplicate but slightly offset
2513 	 * extent buffers for the same range.  It leads to corruptions
2514 	 */
2515 	if ((features & BTRFS_FEATURE_INCOMPAT_MIXED_GROUPS) &&
2516 	    (sectorsize != leafsize)) {
2517 		printk(KERN_WARNING "BTRFS: unequal leaf/node/sector sizes "
2518 				"are not allowed for mixed block groups on %s\n",
2519 				sb->s_id);
2520 		goto fail_alloc;
2521 	}
2522 
2523 	/*
2524 	 * Needn't use the lock because there is no other task which will
2525 	 * update the flag.
2526 	 */
2527 	btrfs_set_super_incompat_flags(disk_super, features);
2528 
2529 	features = btrfs_super_compat_ro_flags(disk_super) &
2530 		~BTRFS_FEATURE_COMPAT_RO_SUPP;
2531 	if (!(sb->s_flags & MS_RDONLY) && features) {
2532 		printk(KERN_ERR "BTRFS: couldn't mount RDWR because of "
2533 		       "unsupported option features (%Lx).\n",
2534 		       features);
2535 		err = -EINVAL;
2536 		goto fail_alloc;
2537 	}
2538 
2539 	max_active = fs_info->thread_pool_size;
2540 
2541 	fs_info->workers =
2542 		btrfs_alloc_workqueue("worker", flags | WQ_HIGHPRI,
2543 				      max_active, 16);
2544 
2545 	fs_info->delalloc_workers =
2546 		btrfs_alloc_workqueue("delalloc", flags, max_active, 2);
2547 
2548 	fs_info->flush_workers =
2549 		btrfs_alloc_workqueue("flush_delalloc", flags, max_active, 0);
2550 
2551 	fs_info->caching_workers =
2552 		btrfs_alloc_workqueue("cache", flags, max_active, 0);
2553 
2554 	/*
2555 	 * a higher idle thresh on the submit workers makes it much more
2556 	 * likely that bios will be send down in a sane order to the
2557 	 * devices
2558 	 */
2559 	fs_info->submit_workers =
2560 		btrfs_alloc_workqueue("submit", flags,
2561 				      min_t(u64, fs_devices->num_devices,
2562 					    max_active), 64);
2563 
2564 	fs_info->fixup_workers =
2565 		btrfs_alloc_workqueue("fixup", flags, 1, 0);
2566 
2567 	/*
2568 	 * endios are largely parallel and should have a very
2569 	 * low idle thresh
2570 	 */
2571 	fs_info->endio_workers =
2572 		btrfs_alloc_workqueue("endio", flags, max_active, 4);
2573 	fs_info->endio_meta_workers =
2574 		btrfs_alloc_workqueue("endio-meta", flags, max_active, 4);
2575 	fs_info->endio_meta_write_workers =
2576 		btrfs_alloc_workqueue("endio-meta-write", flags, max_active, 2);
2577 	fs_info->endio_raid56_workers =
2578 		btrfs_alloc_workqueue("endio-raid56", flags, max_active, 4);
2579 	fs_info->rmw_workers =
2580 		btrfs_alloc_workqueue("rmw", flags, max_active, 2);
2581 	fs_info->endio_write_workers =
2582 		btrfs_alloc_workqueue("endio-write", flags, max_active, 2);
2583 	fs_info->endio_freespace_worker =
2584 		btrfs_alloc_workqueue("freespace-write", flags, max_active, 0);
2585 	fs_info->delayed_workers =
2586 		btrfs_alloc_workqueue("delayed-meta", flags, max_active, 0);
2587 	fs_info->readahead_workers =
2588 		btrfs_alloc_workqueue("readahead", flags, max_active, 2);
2589 	fs_info->qgroup_rescan_workers =
2590 		btrfs_alloc_workqueue("qgroup-rescan", flags, 1, 0);
2591 	fs_info->extent_workers =
2592 		btrfs_alloc_workqueue("extent-refs", flags,
2593 				      min_t(u64, fs_devices->num_devices,
2594 					    max_active), 8);
2595 
2596 	if (!(fs_info->workers && fs_info->delalloc_workers &&
2597 	      fs_info->submit_workers && fs_info->flush_workers &&
2598 	      fs_info->endio_workers && fs_info->endio_meta_workers &&
2599 	      fs_info->endio_meta_write_workers &&
2600 	      fs_info->endio_write_workers && fs_info->endio_raid56_workers &&
2601 	      fs_info->endio_freespace_worker && fs_info->rmw_workers &&
2602 	      fs_info->caching_workers && fs_info->readahead_workers &&
2603 	      fs_info->fixup_workers && fs_info->delayed_workers &&
2604 	      fs_info->fixup_workers && fs_info->extent_workers &&
2605 	      fs_info->qgroup_rescan_workers)) {
2606 		err = -ENOMEM;
2607 		goto fail_sb_buffer;
2608 	}
2609 
2610 	fs_info->bdi.ra_pages *= btrfs_super_num_devices(disk_super);
2611 	fs_info->bdi.ra_pages = max(fs_info->bdi.ra_pages,
2612 				    4 * 1024 * 1024 / PAGE_CACHE_SIZE);
2613 
2614 	tree_root->nodesize = nodesize;
2615 	tree_root->leafsize = leafsize;
2616 	tree_root->sectorsize = sectorsize;
2617 	tree_root->stripesize = stripesize;
2618 
2619 	sb->s_blocksize = sectorsize;
2620 	sb->s_blocksize_bits = blksize_bits(sectorsize);
2621 
2622 	if (btrfs_super_magic(disk_super) != BTRFS_MAGIC) {
2623 		printk(KERN_INFO "BTRFS: valid FS not found on %s\n", sb->s_id);
2624 		goto fail_sb_buffer;
2625 	}
2626 
2627 	if (sectorsize != PAGE_SIZE) {
2628 		printk(KERN_WARNING "BTRFS: Incompatible sector size(%lu) "
2629 		       "found on %s\n", (unsigned long)sectorsize, sb->s_id);
2630 		goto fail_sb_buffer;
2631 	}
2632 
2633 	mutex_lock(&fs_info->chunk_mutex);
2634 	ret = btrfs_read_sys_array(tree_root);
2635 	mutex_unlock(&fs_info->chunk_mutex);
2636 	if (ret) {
2637 		printk(KERN_WARNING "BTRFS: failed to read the system "
2638 		       "array on %s\n", sb->s_id);
2639 		goto fail_sb_buffer;
2640 	}
2641 
2642 	blocksize = btrfs_level_size(tree_root,
2643 				     btrfs_super_chunk_root_level(disk_super));
2644 	generation = btrfs_super_chunk_root_generation(disk_super);
2645 
2646 	__setup_root(nodesize, leafsize, sectorsize, stripesize,
2647 		     chunk_root, fs_info, BTRFS_CHUNK_TREE_OBJECTID);
2648 
2649 	chunk_root->node = read_tree_block(chunk_root,
2650 					   btrfs_super_chunk_root(disk_super),
2651 					   blocksize, generation);
2652 	if (!chunk_root->node ||
2653 	    !test_bit(EXTENT_BUFFER_UPTODATE, &chunk_root->node->bflags)) {
2654 		printk(KERN_WARNING "BTRFS: failed to read chunk root on %s\n",
2655 		       sb->s_id);
2656 		goto fail_tree_roots;
2657 	}
2658 	btrfs_set_root_node(&chunk_root->root_item, chunk_root->node);
2659 	chunk_root->commit_root = btrfs_root_node(chunk_root);
2660 
2661 	read_extent_buffer(chunk_root->node, fs_info->chunk_tree_uuid,
2662 	   btrfs_header_chunk_tree_uuid(chunk_root->node), BTRFS_UUID_SIZE);
2663 
2664 	ret = btrfs_read_chunk_tree(chunk_root);
2665 	if (ret) {
2666 		printk(KERN_WARNING "BTRFS: failed to read chunk tree on %s\n",
2667 		       sb->s_id);
2668 		goto fail_tree_roots;
2669 	}
2670 
2671 	/*
2672 	 * keep the device that is marked to be the target device for the
2673 	 * dev_replace procedure
2674 	 */
2675 	btrfs_close_extra_devices(fs_info, fs_devices, 0);
2676 
2677 	if (!fs_devices->latest_bdev) {
2678 		printk(KERN_CRIT "BTRFS: failed to read devices on %s\n",
2679 		       sb->s_id);
2680 		goto fail_tree_roots;
2681 	}
2682 
2683 retry_root_backup:
2684 	blocksize = btrfs_level_size(tree_root,
2685 				     btrfs_super_root_level(disk_super));
2686 	generation = btrfs_super_generation(disk_super);
2687 
2688 	tree_root->node = read_tree_block(tree_root,
2689 					  btrfs_super_root(disk_super),
2690 					  blocksize, generation);
2691 	if (!tree_root->node ||
2692 	    !test_bit(EXTENT_BUFFER_UPTODATE, &tree_root->node->bflags)) {
2693 		printk(KERN_WARNING "BTRFS: failed to read tree root on %s\n",
2694 		       sb->s_id);
2695 
2696 		goto recovery_tree_root;
2697 	}
2698 
2699 	btrfs_set_root_node(&tree_root->root_item, tree_root->node);
2700 	tree_root->commit_root = btrfs_root_node(tree_root);
2701 	btrfs_set_root_refs(&tree_root->root_item, 1);
2702 
2703 	location.objectid = BTRFS_EXTENT_TREE_OBJECTID;
2704 	location.type = BTRFS_ROOT_ITEM_KEY;
2705 	location.offset = 0;
2706 
2707 	extent_root = btrfs_read_tree_root(tree_root, &location);
2708 	if (IS_ERR(extent_root)) {
2709 		ret = PTR_ERR(extent_root);
2710 		goto recovery_tree_root;
2711 	}
2712 	set_bit(BTRFS_ROOT_TRACK_DIRTY, &extent_root->state);
2713 	fs_info->extent_root = extent_root;
2714 
2715 	location.objectid = BTRFS_DEV_TREE_OBJECTID;
2716 	dev_root = btrfs_read_tree_root(tree_root, &location);
2717 	if (IS_ERR(dev_root)) {
2718 		ret = PTR_ERR(dev_root);
2719 		goto recovery_tree_root;
2720 	}
2721 	set_bit(BTRFS_ROOT_TRACK_DIRTY, &dev_root->state);
2722 	fs_info->dev_root = dev_root;
2723 	btrfs_init_devices_late(fs_info);
2724 
2725 	location.objectid = BTRFS_CSUM_TREE_OBJECTID;
2726 	csum_root = btrfs_read_tree_root(tree_root, &location);
2727 	if (IS_ERR(csum_root)) {
2728 		ret = PTR_ERR(csum_root);
2729 		goto recovery_tree_root;
2730 	}
2731 	set_bit(BTRFS_ROOT_TRACK_DIRTY, &csum_root->state);
2732 	fs_info->csum_root = csum_root;
2733 
2734 	location.objectid = BTRFS_QUOTA_TREE_OBJECTID;
2735 	quota_root = btrfs_read_tree_root(tree_root, &location);
2736 	if (!IS_ERR(quota_root)) {
2737 		set_bit(BTRFS_ROOT_TRACK_DIRTY, &quota_root->state);
2738 		fs_info->quota_enabled = 1;
2739 		fs_info->pending_quota_state = 1;
2740 		fs_info->quota_root = quota_root;
2741 	}
2742 
2743 	location.objectid = BTRFS_UUID_TREE_OBJECTID;
2744 	uuid_root = btrfs_read_tree_root(tree_root, &location);
2745 	if (IS_ERR(uuid_root)) {
2746 		ret = PTR_ERR(uuid_root);
2747 		if (ret != -ENOENT)
2748 			goto recovery_tree_root;
2749 		create_uuid_tree = true;
2750 		check_uuid_tree = false;
2751 	} else {
2752 		set_bit(BTRFS_ROOT_TRACK_DIRTY, &uuid_root->state);
2753 		fs_info->uuid_root = uuid_root;
2754 		create_uuid_tree = false;
2755 		check_uuid_tree =
2756 		    generation != btrfs_super_uuid_tree_generation(disk_super);
2757 	}
2758 
2759 	fs_info->generation = generation;
2760 	fs_info->last_trans_committed = generation;
2761 
2762 	ret = btrfs_recover_balance(fs_info);
2763 	if (ret) {
2764 		printk(KERN_WARNING "BTRFS: failed to recover balance\n");
2765 		goto fail_block_groups;
2766 	}
2767 
2768 	ret = btrfs_init_dev_stats(fs_info);
2769 	if (ret) {
2770 		printk(KERN_ERR "BTRFS: failed to init dev_stats: %d\n",
2771 		       ret);
2772 		goto fail_block_groups;
2773 	}
2774 
2775 	ret = btrfs_init_dev_replace(fs_info);
2776 	if (ret) {
2777 		pr_err("BTRFS: failed to init dev_replace: %d\n", ret);
2778 		goto fail_block_groups;
2779 	}
2780 
2781 	btrfs_close_extra_devices(fs_info, fs_devices, 1);
2782 
2783 	ret = btrfs_sysfs_add_one(fs_info);
2784 	if (ret) {
2785 		pr_err("BTRFS: failed to init sysfs interface: %d\n", ret);
2786 		goto fail_block_groups;
2787 	}
2788 
2789 	ret = btrfs_init_space_info(fs_info);
2790 	if (ret) {
2791 		printk(KERN_ERR "BTRFS: Failed to initial space info: %d\n", ret);
2792 		goto fail_sysfs;
2793 	}
2794 
2795 	ret = btrfs_read_block_groups(extent_root);
2796 	if (ret) {
2797 		printk(KERN_ERR "BTRFS: Failed to read block groups: %d\n", ret);
2798 		goto fail_sysfs;
2799 	}
2800 	fs_info->num_tolerated_disk_barrier_failures =
2801 		btrfs_calc_num_tolerated_disk_barrier_failures(fs_info);
2802 	if (fs_info->fs_devices->missing_devices >
2803 	     fs_info->num_tolerated_disk_barrier_failures &&
2804 	    !(sb->s_flags & MS_RDONLY)) {
2805 		printk(KERN_WARNING "BTRFS: "
2806 			"too many missing devices, writeable mount is not allowed\n");
2807 		goto fail_sysfs;
2808 	}
2809 
2810 	fs_info->cleaner_kthread = kthread_run(cleaner_kthread, tree_root,
2811 					       "btrfs-cleaner");
2812 	if (IS_ERR(fs_info->cleaner_kthread))
2813 		goto fail_sysfs;
2814 
2815 	fs_info->transaction_kthread = kthread_run(transaction_kthread,
2816 						   tree_root,
2817 						   "btrfs-transaction");
2818 	if (IS_ERR(fs_info->transaction_kthread))
2819 		goto fail_cleaner;
2820 
2821 	if (!btrfs_test_opt(tree_root, SSD) &&
2822 	    !btrfs_test_opt(tree_root, NOSSD) &&
2823 	    !fs_info->fs_devices->rotating) {
2824 		printk(KERN_INFO "BTRFS: detected SSD devices, enabling SSD "
2825 		       "mode\n");
2826 		btrfs_set_opt(fs_info->mount_opt, SSD);
2827 	}
2828 
2829 	/* Set the real inode map cache flag */
2830 	if (btrfs_test_opt(tree_root, CHANGE_INODE_CACHE))
2831 		btrfs_set_opt(tree_root->fs_info->mount_opt, INODE_MAP_CACHE);
2832 
2833 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
2834 	if (btrfs_test_opt(tree_root, CHECK_INTEGRITY)) {
2835 		ret = btrfsic_mount(tree_root, fs_devices,
2836 				    btrfs_test_opt(tree_root,
2837 					CHECK_INTEGRITY_INCLUDING_EXTENT_DATA) ?
2838 				    1 : 0,
2839 				    fs_info->check_integrity_print_mask);
2840 		if (ret)
2841 			printk(KERN_WARNING "BTRFS: failed to initialize"
2842 			       " integrity check module %s\n", sb->s_id);
2843 	}
2844 #endif
2845 	ret = btrfs_read_qgroup_config(fs_info);
2846 	if (ret)
2847 		goto fail_trans_kthread;
2848 
2849 	/* do not make disk changes in broken FS */
2850 	if (btrfs_super_log_root(disk_super) != 0) {
2851 		u64 bytenr = btrfs_super_log_root(disk_super);
2852 
2853 		if (fs_devices->rw_devices == 0) {
2854 			printk(KERN_WARNING "BTRFS: log replay required "
2855 			       "on RO media\n");
2856 			err = -EIO;
2857 			goto fail_qgroup;
2858 		}
2859 		blocksize =
2860 		     btrfs_level_size(tree_root,
2861 				      btrfs_super_log_root_level(disk_super));
2862 
2863 		log_tree_root = btrfs_alloc_root(fs_info);
2864 		if (!log_tree_root) {
2865 			err = -ENOMEM;
2866 			goto fail_qgroup;
2867 		}
2868 
2869 		__setup_root(nodesize, leafsize, sectorsize, stripesize,
2870 			     log_tree_root, fs_info, BTRFS_TREE_LOG_OBJECTID);
2871 
2872 		log_tree_root->node = read_tree_block(tree_root, bytenr,
2873 						      blocksize,
2874 						      generation + 1);
2875 		if (!log_tree_root->node ||
2876 		    !extent_buffer_uptodate(log_tree_root->node)) {
2877 			printk(KERN_ERR "BTRFS: failed to read log tree\n");
2878 			free_extent_buffer(log_tree_root->node);
2879 			kfree(log_tree_root);
2880 			goto fail_qgroup;
2881 		}
2882 		/* returns with log_tree_root freed on success */
2883 		ret = btrfs_recover_log_trees(log_tree_root);
2884 		if (ret) {
2885 			btrfs_error(tree_root->fs_info, ret,
2886 				    "Failed to recover log tree");
2887 			free_extent_buffer(log_tree_root->node);
2888 			kfree(log_tree_root);
2889 			goto fail_qgroup;
2890 		}
2891 
2892 		if (sb->s_flags & MS_RDONLY) {
2893 			ret = btrfs_commit_super(tree_root);
2894 			if (ret)
2895 				goto fail_qgroup;
2896 		}
2897 	}
2898 
2899 	ret = btrfs_find_orphan_roots(tree_root);
2900 	if (ret)
2901 		goto fail_qgroup;
2902 
2903 	if (!(sb->s_flags & MS_RDONLY)) {
2904 		ret = btrfs_cleanup_fs_roots(fs_info);
2905 		if (ret)
2906 			goto fail_qgroup;
2907 
2908 		mutex_lock(&fs_info->cleaner_mutex);
2909 		ret = btrfs_recover_relocation(tree_root);
2910 		mutex_unlock(&fs_info->cleaner_mutex);
2911 		if (ret < 0) {
2912 			printk(KERN_WARNING
2913 			       "BTRFS: failed to recover relocation\n");
2914 			err = -EINVAL;
2915 			goto fail_qgroup;
2916 		}
2917 	}
2918 
2919 	location.objectid = BTRFS_FS_TREE_OBJECTID;
2920 	location.type = BTRFS_ROOT_ITEM_KEY;
2921 	location.offset = 0;
2922 
2923 	fs_info->fs_root = btrfs_read_fs_root_no_name(fs_info, &location);
2924 	if (IS_ERR(fs_info->fs_root)) {
2925 		err = PTR_ERR(fs_info->fs_root);
2926 		goto fail_qgroup;
2927 	}
2928 
2929 	if (sb->s_flags & MS_RDONLY)
2930 		return 0;
2931 
2932 	down_read(&fs_info->cleanup_work_sem);
2933 	if ((ret = btrfs_orphan_cleanup(fs_info->fs_root)) ||
2934 	    (ret = btrfs_orphan_cleanup(fs_info->tree_root))) {
2935 		up_read(&fs_info->cleanup_work_sem);
2936 		close_ctree(tree_root);
2937 		return ret;
2938 	}
2939 	up_read(&fs_info->cleanup_work_sem);
2940 
2941 	ret = btrfs_resume_balance_async(fs_info);
2942 	if (ret) {
2943 		printk(KERN_WARNING "BTRFS: failed to resume balance\n");
2944 		close_ctree(tree_root);
2945 		return ret;
2946 	}
2947 
2948 	ret = btrfs_resume_dev_replace_async(fs_info);
2949 	if (ret) {
2950 		pr_warn("BTRFS: failed to resume dev_replace\n");
2951 		close_ctree(tree_root);
2952 		return ret;
2953 	}
2954 
2955 	btrfs_qgroup_rescan_resume(fs_info);
2956 
2957 	if (create_uuid_tree) {
2958 		pr_info("BTRFS: creating UUID tree\n");
2959 		ret = btrfs_create_uuid_tree(fs_info);
2960 		if (ret) {
2961 			pr_warn("BTRFS: failed to create the UUID tree %d\n",
2962 				ret);
2963 			close_ctree(tree_root);
2964 			return ret;
2965 		}
2966 	} else if (check_uuid_tree ||
2967 		   btrfs_test_opt(tree_root, RESCAN_UUID_TREE)) {
2968 		pr_info("BTRFS: checking UUID tree\n");
2969 		ret = btrfs_check_uuid_tree(fs_info);
2970 		if (ret) {
2971 			pr_warn("BTRFS: failed to check the UUID tree %d\n",
2972 				ret);
2973 			close_ctree(tree_root);
2974 			return ret;
2975 		}
2976 	} else {
2977 		fs_info->update_uuid_tree_gen = 1;
2978 	}
2979 
2980 	return 0;
2981 
2982 fail_qgroup:
2983 	btrfs_free_qgroup_config(fs_info);
2984 fail_trans_kthread:
2985 	kthread_stop(fs_info->transaction_kthread);
2986 	btrfs_cleanup_transaction(fs_info->tree_root);
2987 	btrfs_free_fs_roots(fs_info);
2988 fail_cleaner:
2989 	kthread_stop(fs_info->cleaner_kthread);
2990 
2991 	/*
2992 	 * make sure we're done with the btree inode before we stop our
2993 	 * kthreads
2994 	 */
2995 	filemap_write_and_wait(fs_info->btree_inode->i_mapping);
2996 
2997 fail_sysfs:
2998 	btrfs_sysfs_remove_one(fs_info);
2999 
3000 fail_block_groups:
3001 	btrfs_put_block_group_cache(fs_info);
3002 	btrfs_free_block_groups(fs_info);
3003 
3004 fail_tree_roots:
3005 	free_root_pointers(fs_info, 1);
3006 	invalidate_inode_pages2(fs_info->btree_inode->i_mapping);
3007 
3008 fail_sb_buffer:
3009 	btrfs_stop_all_workers(fs_info);
3010 fail_alloc:
3011 fail_iput:
3012 	btrfs_mapping_tree_free(&fs_info->mapping_tree);
3013 
3014 	iput(fs_info->btree_inode);
3015 fail_bio_counter:
3016 	percpu_counter_destroy(&fs_info->bio_counter);
3017 fail_delalloc_bytes:
3018 	percpu_counter_destroy(&fs_info->delalloc_bytes);
3019 fail_dirty_metadata_bytes:
3020 	percpu_counter_destroy(&fs_info->dirty_metadata_bytes);
3021 fail_bdi:
3022 	bdi_destroy(&fs_info->bdi);
3023 fail_srcu:
3024 	cleanup_srcu_struct(&fs_info->subvol_srcu);
3025 fail:
3026 	btrfs_free_stripe_hash_table(fs_info);
3027 	btrfs_close_devices(fs_info->fs_devices);
3028 	return err;
3029 
3030 recovery_tree_root:
3031 	if (!btrfs_test_opt(tree_root, RECOVERY))
3032 		goto fail_tree_roots;
3033 
3034 	free_root_pointers(fs_info, 0);
3035 
3036 	/* don't use the log in recovery mode, it won't be valid */
3037 	btrfs_set_super_log_root(disk_super, 0);
3038 
3039 	/* we can't trust the free space cache either */
3040 	btrfs_set_opt(fs_info->mount_opt, CLEAR_CACHE);
3041 
3042 	ret = next_root_backup(fs_info, fs_info->super_copy,
3043 			       &num_backups_tried, &backup_index);
3044 	if (ret == -1)
3045 		goto fail_block_groups;
3046 	goto retry_root_backup;
3047 }
3048 
3049 static void btrfs_end_buffer_write_sync(struct buffer_head *bh, int uptodate)
3050 {
3051 	if (uptodate) {
3052 		set_buffer_uptodate(bh);
3053 	} else {
3054 		struct btrfs_device *device = (struct btrfs_device *)
3055 			bh->b_private;
3056 
3057 		printk_ratelimited_in_rcu(KERN_WARNING "BTRFS: lost page write due to "
3058 					  "I/O error on %s\n",
3059 					  rcu_str_deref(device->name));
3060 		/* note, we dont' set_buffer_write_io_error because we have
3061 		 * our own ways of dealing with the IO errors
3062 		 */
3063 		clear_buffer_uptodate(bh);
3064 		btrfs_dev_stat_inc_and_print(device, BTRFS_DEV_STAT_WRITE_ERRS);
3065 	}
3066 	unlock_buffer(bh);
3067 	put_bh(bh);
3068 }
3069 
3070 struct buffer_head *btrfs_read_dev_super(struct block_device *bdev)
3071 {
3072 	struct buffer_head *bh;
3073 	struct buffer_head *latest = NULL;
3074 	struct btrfs_super_block *super;
3075 	int i;
3076 	u64 transid = 0;
3077 	u64 bytenr;
3078 
3079 	/* we would like to check all the supers, but that would make
3080 	 * a btrfs mount succeed after a mkfs from a different FS.
3081 	 * So, we need to add a special mount option to scan for
3082 	 * later supers, using BTRFS_SUPER_MIRROR_MAX instead
3083 	 */
3084 	for (i = 0; i < 1; i++) {
3085 		bytenr = btrfs_sb_offset(i);
3086 		if (bytenr + BTRFS_SUPER_INFO_SIZE >=
3087 					i_size_read(bdev->bd_inode))
3088 			break;
3089 		bh = __bread(bdev, bytenr / 4096,
3090 					BTRFS_SUPER_INFO_SIZE);
3091 		if (!bh)
3092 			continue;
3093 
3094 		super = (struct btrfs_super_block *)bh->b_data;
3095 		if (btrfs_super_bytenr(super) != bytenr ||
3096 		    btrfs_super_magic(super) != BTRFS_MAGIC) {
3097 			brelse(bh);
3098 			continue;
3099 		}
3100 
3101 		if (!latest || btrfs_super_generation(super) > transid) {
3102 			brelse(latest);
3103 			latest = bh;
3104 			transid = btrfs_super_generation(super);
3105 		} else {
3106 			brelse(bh);
3107 		}
3108 	}
3109 	return latest;
3110 }
3111 
3112 /*
3113  * this should be called twice, once with wait == 0 and
3114  * once with wait == 1.  When wait == 0 is done, all the buffer heads
3115  * we write are pinned.
3116  *
3117  * They are released when wait == 1 is done.
3118  * max_mirrors must be the same for both runs, and it indicates how
3119  * many supers on this one device should be written.
3120  *
3121  * max_mirrors == 0 means to write them all.
3122  */
3123 static int write_dev_supers(struct btrfs_device *device,
3124 			    struct btrfs_super_block *sb,
3125 			    int do_barriers, int wait, int max_mirrors)
3126 {
3127 	struct buffer_head *bh;
3128 	int i;
3129 	int ret;
3130 	int errors = 0;
3131 	u32 crc;
3132 	u64 bytenr;
3133 
3134 	if (max_mirrors == 0)
3135 		max_mirrors = BTRFS_SUPER_MIRROR_MAX;
3136 
3137 	for (i = 0; i < max_mirrors; i++) {
3138 		bytenr = btrfs_sb_offset(i);
3139 		if (bytenr + BTRFS_SUPER_INFO_SIZE >= device->total_bytes)
3140 			break;
3141 
3142 		if (wait) {
3143 			bh = __find_get_block(device->bdev, bytenr / 4096,
3144 					      BTRFS_SUPER_INFO_SIZE);
3145 			if (!bh) {
3146 				errors++;
3147 				continue;
3148 			}
3149 			wait_on_buffer(bh);
3150 			if (!buffer_uptodate(bh))
3151 				errors++;
3152 
3153 			/* drop our reference */
3154 			brelse(bh);
3155 
3156 			/* drop the reference from the wait == 0 run */
3157 			brelse(bh);
3158 			continue;
3159 		} else {
3160 			btrfs_set_super_bytenr(sb, bytenr);
3161 
3162 			crc = ~(u32)0;
3163 			crc = btrfs_csum_data((char *)sb +
3164 					      BTRFS_CSUM_SIZE, crc,
3165 					      BTRFS_SUPER_INFO_SIZE -
3166 					      BTRFS_CSUM_SIZE);
3167 			btrfs_csum_final(crc, sb->csum);
3168 
3169 			/*
3170 			 * one reference for us, and we leave it for the
3171 			 * caller
3172 			 */
3173 			bh = __getblk(device->bdev, bytenr / 4096,
3174 				      BTRFS_SUPER_INFO_SIZE);
3175 			if (!bh) {
3176 				printk(KERN_ERR "BTRFS: couldn't get super "
3177 				       "buffer head for bytenr %Lu\n", bytenr);
3178 				errors++;
3179 				continue;
3180 			}
3181 
3182 			memcpy(bh->b_data, sb, BTRFS_SUPER_INFO_SIZE);
3183 
3184 			/* one reference for submit_bh */
3185 			get_bh(bh);
3186 
3187 			set_buffer_uptodate(bh);
3188 			lock_buffer(bh);
3189 			bh->b_end_io = btrfs_end_buffer_write_sync;
3190 			bh->b_private = device;
3191 		}
3192 
3193 		/*
3194 		 * we fua the first super.  The others we allow
3195 		 * to go down lazy.
3196 		 */
3197 		if (i == 0)
3198 			ret = btrfsic_submit_bh(WRITE_FUA, bh);
3199 		else
3200 			ret = btrfsic_submit_bh(WRITE_SYNC, bh);
3201 		if (ret)
3202 			errors++;
3203 	}
3204 	return errors < i ? 0 : -1;
3205 }
3206 
3207 /*
3208  * endio for the write_dev_flush, this will wake anyone waiting
3209  * for the barrier when it is done
3210  */
3211 static void btrfs_end_empty_barrier(struct bio *bio, int err)
3212 {
3213 	if (err) {
3214 		if (err == -EOPNOTSUPP)
3215 			set_bit(BIO_EOPNOTSUPP, &bio->bi_flags);
3216 		clear_bit(BIO_UPTODATE, &bio->bi_flags);
3217 	}
3218 	if (bio->bi_private)
3219 		complete(bio->bi_private);
3220 	bio_put(bio);
3221 }
3222 
3223 /*
3224  * trigger flushes for one the devices.  If you pass wait == 0, the flushes are
3225  * sent down.  With wait == 1, it waits for the previous flush.
3226  *
3227  * any device where the flush fails with eopnotsupp are flagged as not-barrier
3228  * capable
3229  */
3230 static int write_dev_flush(struct btrfs_device *device, int wait)
3231 {
3232 	struct bio *bio;
3233 	int ret = 0;
3234 
3235 	if (device->nobarriers)
3236 		return 0;
3237 
3238 	if (wait) {
3239 		bio = device->flush_bio;
3240 		if (!bio)
3241 			return 0;
3242 
3243 		wait_for_completion(&device->flush_wait);
3244 
3245 		if (bio_flagged(bio, BIO_EOPNOTSUPP)) {
3246 			printk_in_rcu("BTRFS: disabling barriers on dev %s\n",
3247 				      rcu_str_deref(device->name));
3248 			device->nobarriers = 1;
3249 		} else if (!bio_flagged(bio, BIO_UPTODATE)) {
3250 			ret = -EIO;
3251 			btrfs_dev_stat_inc_and_print(device,
3252 				BTRFS_DEV_STAT_FLUSH_ERRS);
3253 		}
3254 
3255 		/* drop the reference from the wait == 0 run */
3256 		bio_put(bio);
3257 		device->flush_bio = NULL;
3258 
3259 		return ret;
3260 	}
3261 
3262 	/*
3263 	 * one reference for us, and we leave it for the
3264 	 * caller
3265 	 */
3266 	device->flush_bio = NULL;
3267 	bio = btrfs_io_bio_alloc(GFP_NOFS, 0);
3268 	if (!bio)
3269 		return -ENOMEM;
3270 
3271 	bio->bi_end_io = btrfs_end_empty_barrier;
3272 	bio->bi_bdev = device->bdev;
3273 	init_completion(&device->flush_wait);
3274 	bio->bi_private = &device->flush_wait;
3275 	device->flush_bio = bio;
3276 
3277 	bio_get(bio);
3278 	btrfsic_submit_bio(WRITE_FLUSH, bio);
3279 
3280 	return 0;
3281 }
3282 
3283 /*
3284  * send an empty flush down to each device in parallel,
3285  * then wait for them
3286  */
3287 static int barrier_all_devices(struct btrfs_fs_info *info)
3288 {
3289 	struct list_head *head;
3290 	struct btrfs_device *dev;
3291 	int errors_send = 0;
3292 	int errors_wait = 0;
3293 	int ret;
3294 
3295 	/* send down all the barriers */
3296 	head = &info->fs_devices->devices;
3297 	list_for_each_entry_rcu(dev, head, dev_list) {
3298 		if (dev->missing)
3299 			continue;
3300 		if (!dev->bdev) {
3301 			errors_send++;
3302 			continue;
3303 		}
3304 		if (!dev->in_fs_metadata || !dev->writeable)
3305 			continue;
3306 
3307 		ret = write_dev_flush(dev, 0);
3308 		if (ret)
3309 			errors_send++;
3310 	}
3311 
3312 	/* wait for all the barriers */
3313 	list_for_each_entry_rcu(dev, head, dev_list) {
3314 		if (dev->missing)
3315 			continue;
3316 		if (!dev->bdev) {
3317 			errors_wait++;
3318 			continue;
3319 		}
3320 		if (!dev->in_fs_metadata || !dev->writeable)
3321 			continue;
3322 
3323 		ret = write_dev_flush(dev, 1);
3324 		if (ret)
3325 			errors_wait++;
3326 	}
3327 	if (errors_send > info->num_tolerated_disk_barrier_failures ||
3328 	    errors_wait > info->num_tolerated_disk_barrier_failures)
3329 		return -EIO;
3330 	return 0;
3331 }
3332 
3333 int btrfs_calc_num_tolerated_disk_barrier_failures(
3334 	struct btrfs_fs_info *fs_info)
3335 {
3336 	struct btrfs_ioctl_space_info space;
3337 	struct btrfs_space_info *sinfo;
3338 	u64 types[] = {BTRFS_BLOCK_GROUP_DATA,
3339 		       BTRFS_BLOCK_GROUP_SYSTEM,
3340 		       BTRFS_BLOCK_GROUP_METADATA,
3341 		       BTRFS_BLOCK_GROUP_DATA | BTRFS_BLOCK_GROUP_METADATA};
3342 	int num_types = 4;
3343 	int i;
3344 	int c;
3345 	int num_tolerated_disk_barrier_failures =
3346 		(int)fs_info->fs_devices->num_devices;
3347 
3348 	for (i = 0; i < num_types; i++) {
3349 		struct btrfs_space_info *tmp;
3350 
3351 		sinfo = NULL;
3352 		rcu_read_lock();
3353 		list_for_each_entry_rcu(tmp, &fs_info->space_info, list) {
3354 			if (tmp->flags == types[i]) {
3355 				sinfo = tmp;
3356 				break;
3357 			}
3358 		}
3359 		rcu_read_unlock();
3360 
3361 		if (!sinfo)
3362 			continue;
3363 
3364 		down_read(&sinfo->groups_sem);
3365 		for (c = 0; c < BTRFS_NR_RAID_TYPES; c++) {
3366 			if (!list_empty(&sinfo->block_groups[c])) {
3367 				u64 flags;
3368 
3369 				btrfs_get_block_group_info(
3370 					&sinfo->block_groups[c], &space);
3371 				if (space.total_bytes == 0 ||
3372 				    space.used_bytes == 0)
3373 					continue;
3374 				flags = space.flags;
3375 				/*
3376 				 * return
3377 				 * 0: if dup, single or RAID0 is configured for
3378 				 *    any of metadata, system or data, else
3379 				 * 1: if RAID5 is configured, or if RAID1 or
3380 				 *    RAID10 is configured and only two mirrors
3381 				 *    are used, else
3382 				 * 2: if RAID6 is configured, else
3383 				 * num_mirrors - 1: if RAID1 or RAID10 is
3384 				 *                  configured and more than
3385 				 *                  2 mirrors are used.
3386 				 */
3387 				if (num_tolerated_disk_barrier_failures > 0 &&
3388 				    ((flags & (BTRFS_BLOCK_GROUP_DUP |
3389 					       BTRFS_BLOCK_GROUP_RAID0)) ||
3390 				     ((flags & BTRFS_BLOCK_GROUP_PROFILE_MASK)
3391 				      == 0)))
3392 					num_tolerated_disk_barrier_failures = 0;
3393 				else if (num_tolerated_disk_barrier_failures > 1) {
3394 					if (flags & (BTRFS_BLOCK_GROUP_RAID1 |
3395 					    BTRFS_BLOCK_GROUP_RAID5 |
3396 					    BTRFS_BLOCK_GROUP_RAID10)) {
3397 						num_tolerated_disk_barrier_failures = 1;
3398 					} else if (flags &
3399 						   BTRFS_BLOCK_GROUP_RAID6) {
3400 						num_tolerated_disk_barrier_failures = 2;
3401 					}
3402 				}
3403 			}
3404 		}
3405 		up_read(&sinfo->groups_sem);
3406 	}
3407 
3408 	return num_tolerated_disk_barrier_failures;
3409 }
3410 
3411 static int write_all_supers(struct btrfs_root *root, int max_mirrors)
3412 {
3413 	struct list_head *head;
3414 	struct btrfs_device *dev;
3415 	struct btrfs_super_block *sb;
3416 	struct btrfs_dev_item *dev_item;
3417 	int ret;
3418 	int do_barriers;
3419 	int max_errors;
3420 	int total_errors = 0;
3421 	u64 flags;
3422 
3423 	do_barriers = !btrfs_test_opt(root, NOBARRIER);
3424 	backup_super_roots(root->fs_info);
3425 
3426 	sb = root->fs_info->super_for_commit;
3427 	dev_item = &sb->dev_item;
3428 
3429 	mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
3430 	head = &root->fs_info->fs_devices->devices;
3431 	max_errors = btrfs_super_num_devices(root->fs_info->super_copy) - 1;
3432 
3433 	if (do_barriers) {
3434 		ret = barrier_all_devices(root->fs_info);
3435 		if (ret) {
3436 			mutex_unlock(
3437 				&root->fs_info->fs_devices->device_list_mutex);
3438 			btrfs_error(root->fs_info, ret,
3439 				    "errors while submitting device barriers.");
3440 			return ret;
3441 		}
3442 	}
3443 
3444 	list_for_each_entry_rcu(dev, head, dev_list) {
3445 		if (!dev->bdev) {
3446 			total_errors++;
3447 			continue;
3448 		}
3449 		if (!dev->in_fs_metadata || !dev->writeable)
3450 			continue;
3451 
3452 		btrfs_set_stack_device_generation(dev_item, 0);
3453 		btrfs_set_stack_device_type(dev_item, dev->type);
3454 		btrfs_set_stack_device_id(dev_item, dev->devid);
3455 		btrfs_set_stack_device_total_bytes(dev_item, dev->total_bytes);
3456 		btrfs_set_stack_device_bytes_used(dev_item, dev->bytes_used);
3457 		btrfs_set_stack_device_io_align(dev_item, dev->io_align);
3458 		btrfs_set_stack_device_io_width(dev_item, dev->io_width);
3459 		btrfs_set_stack_device_sector_size(dev_item, dev->sector_size);
3460 		memcpy(dev_item->uuid, dev->uuid, BTRFS_UUID_SIZE);
3461 		memcpy(dev_item->fsid, dev->fs_devices->fsid, BTRFS_UUID_SIZE);
3462 
3463 		flags = btrfs_super_flags(sb);
3464 		btrfs_set_super_flags(sb, flags | BTRFS_HEADER_FLAG_WRITTEN);
3465 
3466 		ret = write_dev_supers(dev, sb, do_barriers, 0, max_mirrors);
3467 		if (ret)
3468 			total_errors++;
3469 	}
3470 	if (total_errors > max_errors) {
3471 		btrfs_err(root->fs_info, "%d errors while writing supers",
3472 		       total_errors);
3473 		mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
3474 
3475 		/* FUA is masked off if unsupported and can't be the reason */
3476 		btrfs_error(root->fs_info, -EIO,
3477 			    "%d errors while writing supers", total_errors);
3478 		return -EIO;
3479 	}
3480 
3481 	total_errors = 0;
3482 	list_for_each_entry_rcu(dev, head, dev_list) {
3483 		if (!dev->bdev)
3484 			continue;
3485 		if (!dev->in_fs_metadata || !dev->writeable)
3486 			continue;
3487 
3488 		ret = write_dev_supers(dev, sb, do_barriers, 1, max_mirrors);
3489 		if (ret)
3490 			total_errors++;
3491 	}
3492 	mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
3493 	if (total_errors > max_errors) {
3494 		btrfs_error(root->fs_info, -EIO,
3495 			    "%d errors while writing supers", total_errors);
3496 		return -EIO;
3497 	}
3498 	return 0;
3499 }
3500 
3501 int write_ctree_super(struct btrfs_trans_handle *trans,
3502 		      struct btrfs_root *root, int max_mirrors)
3503 {
3504 	return write_all_supers(root, max_mirrors);
3505 }
3506 
3507 /* Drop a fs root from the radix tree and free it. */
3508 void btrfs_drop_and_free_fs_root(struct btrfs_fs_info *fs_info,
3509 				  struct btrfs_root *root)
3510 {
3511 	spin_lock(&fs_info->fs_roots_radix_lock);
3512 	radix_tree_delete(&fs_info->fs_roots_radix,
3513 			  (unsigned long)root->root_key.objectid);
3514 	spin_unlock(&fs_info->fs_roots_radix_lock);
3515 
3516 	if (btrfs_root_refs(&root->root_item) == 0)
3517 		synchronize_srcu(&fs_info->subvol_srcu);
3518 
3519 	if (test_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state))
3520 		btrfs_free_log(NULL, root);
3521 
3522 	if (root->free_ino_pinned)
3523 		__btrfs_remove_free_space_cache(root->free_ino_pinned);
3524 	if (root->free_ino_ctl)
3525 		__btrfs_remove_free_space_cache(root->free_ino_ctl);
3526 	free_fs_root(root);
3527 }
3528 
3529 static void free_fs_root(struct btrfs_root *root)
3530 {
3531 	iput(root->cache_inode);
3532 	WARN_ON(!RB_EMPTY_ROOT(&root->inode_tree));
3533 	btrfs_free_block_rsv(root, root->orphan_block_rsv);
3534 	root->orphan_block_rsv = NULL;
3535 	if (root->anon_dev)
3536 		free_anon_bdev(root->anon_dev);
3537 	if (root->subv_writers)
3538 		btrfs_free_subvolume_writers(root->subv_writers);
3539 	free_extent_buffer(root->node);
3540 	free_extent_buffer(root->commit_root);
3541 	kfree(root->free_ino_ctl);
3542 	kfree(root->free_ino_pinned);
3543 	kfree(root->name);
3544 	btrfs_put_fs_root(root);
3545 }
3546 
3547 void btrfs_free_fs_root(struct btrfs_root *root)
3548 {
3549 	free_fs_root(root);
3550 }
3551 
3552 int btrfs_cleanup_fs_roots(struct btrfs_fs_info *fs_info)
3553 {
3554 	u64 root_objectid = 0;
3555 	struct btrfs_root *gang[8];
3556 	int i = 0;
3557 	int err = 0;
3558 	unsigned int ret = 0;
3559 	int index;
3560 
3561 	while (1) {
3562 		index = srcu_read_lock(&fs_info->subvol_srcu);
3563 		ret = radix_tree_gang_lookup(&fs_info->fs_roots_radix,
3564 					     (void **)gang, root_objectid,
3565 					     ARRAY_SIZE(gang));
3566 		if (!ret) {
3567 			srcu_read_unlock(&fs_info->subvol_srcu, index);
3568 			break;
3569 		}
3570 		root_objectid = gang[ret - 1]->root_key.objectid + 1;
3571 
3572 		for (i = 0; i < ret; i++) {
3573 			/* Avoid to grab roots in dead_roots */
3574 			if (btrfs_root_refs(&gang[i]->root_item) == 0) {
3575 				gang[i] = NULL;
3576 				continue;
3577 			}
3578 			/* grab all the search result for later use */
3579 			gang[i] = btrfs_grab_fs_root(gang[i]);
3580 		}
3581 		srcu_read_unlock(&fs_info->subvol_srcu, index);
3582 
3583 		for (i = 0; i < ret; i++) {
3584 			if (!gang[i])
3585 				continue;
3586 			root_objectid = gang[i]->root_key.objectid;
3587 			err = btrfs_orphan_cleanup(gang[i]);
3588 			if (err)
3589 				break;
3590 			btrfs_put_fs_root(gang[i]);
3591 		}
3592 		root_objectid++;
3593 	}
3594 
3595 	/* release the uncleaned roots due to error */
3596 	for (; i < ret; i++) {
3597 		if (gang[i])
3598 			btrfs_put_fs_root(gang[i]);
3599 	}
3600 	return err;
3601 }
3602 
3603 int btrfs_commit_super(struct btrfs_root *root)
3604 {
3605 	struct btrfs_trans_handle *trans;
3606 
3607 	mutex_lock(&root->fs_info->cleaner_mutex);
3608 	btrfs_run_delayed_iputs(root);
3609 	mutex_unlock(&root->fs_info->cleaner_mutex);
3610 	wake_up_process(root->fs_info->cleaner_kthread);
3611 
3612 	/* wait until ongoing cleanup work done */
3613 	down_write(&root->fs_info->cleanup_work_sem);
3614 	up_write(&root->fs_info->cleanup_work_sem);
3615 
3616 	trans = btrfs_join_transaction(root);
3617 	if (IS_ERR(trans))
3618 		return PTR_ERR(trans);
3619 	return btrfs_commit_transaction(trans, root);
3620 }
3621 
3622 int close_ctree(struct btrfs_root *root)
3623 {
3624 	struct btrfs_fs_info *fs_info = root->fs_info;
3625 	int ret;
3626 
3627 	fs_info->closing = 1;
3628 	smp_mb();
3629 
3630 	/* wait for the uuid_scan task to finish */
3631 	down(&fs_info->uuid_tree_rescan_sem);
3632 	/* avoid complains from lockdep et al., set sem back to initial state */
3633 	up(&fs_info->uuid_tree_rescan_sem);
3634 
3635 	/* pause restriper - we want to resume on mount */
3636 	btrfs_pause_balance(fs_info);
3637 
3638 	btrfs_dev_replace_suspend_for_unmount(fs_info);
3639 
3640 	btrfs_scrub_cancel(fs_info);
3641 
3642 	/* wait for any defraggers to finish */
3643 	wait_event(fs_info->transaction_wait,
3644 		   (atomic_read(&fs_info->defrag_running) == 0));
3645 
3646 	/* clear out the rbtree of defraggable inodes */
3647 	btrfs_cleanup_defrag_inodes(fs_info);
3648 
3649 	cancel_work_sync(&fs_info->async_reclaim_work);
3650 
3651 	if (!(fs_info->sb->s_flags & MS_RDONLY)) {
3652 		ret = btrfs_commit_super(root);
3653 		if (ret)
3654 			btrfs_err(root->fs_info, "commit super ret %d", ret);
3655 	}
3656 
3657 	if (test_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state))
3658 		btrfs_error_commit_super(root);
3659 
3660 	kthread_stop(fs_info->transaction_kthread);
3661 	kthread_stop(fs_info->cleaner_kthread);
3662 
3663 	fs_info->closing = 2;
3664 	smp_mb();
3665 
3666 	btrfs_free_qgroup_config(root->fs_info);
3667 
3668 	if (percpu_counter_sum(&fs_info->delalloc_bytes)) {
3669 		btrfs_info(root->fs_info, "at unmount delalloc count %lld",
3670 		       percpu_counter_sum(&fs_info->delalloc_bytes));
3671 	}
3672 
3673 	btrfs_sysfs_remove_one(fs_info);
3674 
3675 	btrfs_free_fs_roots(fs_info);
3676 
3677 	btrfs_put_block_group_cache(fs_info);
3678 
3679 	btrfs_free_block_groups(fs_info);
3680 
3681 	/*
3682 	 * we must make sure there is not any read request to
3683 	 * submit after we stopping all workers.
3684 	 */
3685 	invalidate_inode_pages2(fs_info->btree_inode->i_mapping);
3686 	btrfs_stop_all_workers(fs_info);
3687 
3688 	free_root_pointers(fs_info, 1);
3689 
3690 	iput(fs_info->btree_inode);
3691 
3692 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
3693 	if (btrfs_test_opt(root, CHECK_INTEGRITY))
3694 		btrfsic_unmount(root, fs_info->fs_devices);
3695 #endif
3696 
3697 	btrfs_close_devices(fs_info->fs_devices);
3698 	btrfs_mapping_tree_free(&fs_info->mapping_tree);
3699 
3700 	percpu_counter_destroy(&fs_info->dirty_metadata_bytes);
3701 	percpu_counter_destroy(&fs_info->delalloc_bytes);
3702 	percpu_counter_destroy(&fs_info->bio_counter);
3703 	bdi_destroy(&fs_info->bdi);
3704 	cleanup_srcu_struct(&fs_info->subvol_srcu);
3705 
3706 	btrfs_free_stripe_hash_table(fs_info);
3707 
3708 	btrfs_free_block_rsv(root, root->orphan_block_rsv);
3709 	root->orphan_block_rsv = NULL;
3710 
3711 	return 0;
3712 }
3713 
3714 int btrfs_buffer_uptodate(struct extent_buffer *buf, u64 parent_transid,
3715 			  int atomic)
3716 {
3717 	int ret;
3718 	struct inode *btree_inode = buf->pages[0]->mapping->host;
3719 
3720 	ret = extent_buffer_uptodate(buf);
3721 	if (!ret)
3722 		return ret;
3723 
3724 	ret = verify_parent_transid(&BTRFS_I(btree_inode)->io_tree, buf,
3725 				    parent_transid, atomic);
3726 	if (ret == -EAGAIN)
3727 		return ret;
3728 	return !ret;
3729 }
3730 
3731 int btrfs_set_buffer_uptodate(struct extent_buffer *buf)
3732 {
3733 	return set_extent_buffer_uptodate(buf);
3734 }
3735 
3736 void btrfs_mark_buffer_dirty(struct extent_buffer *buf)
3737 {
3738 	struct btrfs_root *root;
3739 	u64 transid = btrfs_header_generation(buf);
3740 	int was_dirty;
3741 
3742 #ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
3743 	/*
3744 	 * This is a fast path so only do this check if we have sanity tests
3745 	 * enabled.  Normal people shouldn't be marking dummy buffers as dirty
3746 	 * outside of the sanity tests.
3747 	 */
3748 	if (unlikely(test_bit(EXTENT_BUFFER_DUMMY, &buf->bflags)))
3749 		return;
3750 #endif
3751 	root = BTRFS_I(buf->pages[0]->mapping->host)->root;
3752 	btrfs_assert_tree_locked(buf);
3753 	if (transid != root->fs_info->generation)
3754 		WARN(1, KERN_CRIT "btrfs transid mismatch buffer %llu, "
3755 		       "found %llu running %llu\n",
3756 			buf->start, transid, root->fs_info->generation);
3757 	was_dirty = set_extent_buffer_dirty(buf);
3758 	if (!was_dirty)
3759 		__percpu_counter_add(&root->fs_info->dirty_metadata_bytes,
3760 				     buf->len,
3761 				     root->fs_info->dirty_metadata_batch);
3762 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
3763 	if (btrfs_header_level(buf) == 0 && check_leaf(root, buf)) {
3764 		btrfs_print_leaf(root, buf);
3765 		ASSERT(0);
3766 	}
3767 #endif
3768 }
3769 
3770 static void __btrfs_btree_balance_dirty(struct btrfs_root *root,
3771 					int flush_delayed)
3772 {
3773 	/*
3774 	 * looks as though older kernels can get into trouble with
3775 	 * this code, they end up stuck in balance_dirty_pages forever
3776 	 */
3777 	int ret;
3778 
3779 	if (current->flags & PF_MEMALLOC)
3780 		return;
3781 
3782 	if (flush_delayed)
3783 		btrfs_balance_delayed_items(root);
3784 
3785 	ret = percpu_counter_compare(&root->fs_info->dirty_metadata_bytes,
3786 				     BTRFS_DIRTY_METADATA_THRESH);
3787 	if (ret > 0) {
3788 		balance_dirty_pages_ratelimited(
3789 				   root->fs_info->btree_inode->i_mapping);
3790 	}
3791 	return;
3792 }
3793 
3794 void btrfs_btree_balance_dirty(struct btrfs_root *root)
3795 {
3796 	__btrfs_btree_balance_dirty(root, 1);
3797 }
3798 
3799 void btrfs_btree_balance_dirty_nodelay(struct btrfs_root *root)
3800 {
3801 	__btrfs_btree_balance_dirty(root, 0);
3802 }
3803 
3804 int btrfs_read_buffer(struct extent_buffer *buf, u64 parent_transid)
3805 {
3806 	struct btrfs_root *root = BTRFS_I(buf->pages[0]->mapping->host)->root;
3807 	return btree_read_extent_buffer_pages(root, buf, 0, parent_transid);
3808 }
3809 
3810 static int btrfs_check_super_valid(struct btrfs_fs_info *fs_info,
3811 			      int read_only)
3812 {
3813 	/*
3814 	 * Placeholder for checks
3815 	 */
3816 	return 0;
3817 }
3818 
3819 static void btrfs_error_commit_super(struct btrfs_root *root)
3820 {
3821 	mutex_lock(&root->fs_info->cleaner_mutex);
3822 	btrfs_run_delayed_iputs(root);
3823 	mutex_unlock(&root->fs_info->cleaner_mutex);
3824 
3825 	down_write(&root->fs_info->cleanup_work_sem);
3826 	up_write(&root->fs_info->cleanup_work_sem);
3827 
3828 	/* cleanup FS via transaction */
3829 	btrfs_cleanup_transaction(root);
3830 }
3831 
3832 static void btrfs_destroy_ordered_operations(struct btrfs_transaction *t,
3833 					     struct btrfs_root *root)
3834 {
3835 	struct btrfs_inode *btrfs_inode;
3836 	struct list_head splice;
3837 
3838 	INIT_LIST_HEAD(&splice);
3839 
3840 	mutex_lock(&root->fs_info->ordered_operations_mutex);
3841 	spin_lock(&root->fs_info->ordered_root_lock);
3842 
3843 	list_splice_init(&t->ordered_operations, &splice);
3844 	while (!list_empty(&splice)) {
3845 		btrfs_inode = list_entry(splice.next, struct btrfs_inode,
3846 					 ordered_operations);
3847 
3848 		list_del_init(&btrfs_inode->ordered_operations);
3849 		spin_unlock(&root->fs_info->ordered_root_lock);
3850 
3851 		btrfs_invalidate_inodes(btrfs_inode->root);
3852 
3853 		spin_lock(&root->fs_info->ordered_root_lock);
3854 	}
3855 
3856 	spin_unlock(&root->fs_info->ordered_root_lock);
3857 	mutex_unlock(&root->fs_info->ordered_operations_mutex);
3858 }
3859 
3860 static void btrfs_destroy_ordered_extents(struct btrfs_root *root)
3861 {
3862 	struct btrfs_ordered_extent *ordered;
3863 
3864 	spin_lock(&root->ordered_extent_lock);
3865 	/*
3866 	 * This will just short circuit the ordered completion stuff which will
3867 	 * make sure the ordered extent gets properly cleaned up.
3868 	 */
3869 	list_for_each_entry(ordered, &root->ordered_extents,
3870 			    root_extent_list)
3871 		set_bit(BTRFS_ORDERED_IOERR, &ordered->flags);
3872 	spin_unlock(&root->ordered_extent_lock);
3873 }
3874 
3875 static void btrfs_destroy_all_ordered_extents(struct btrfs_fs_info *fs_info)
3876 {
3877 	struct btrfs_root *root;
3878 	struct list_head splice;
3879 
3880 	INIT_LIST_HEAD(&splice);
3881 
3882 	spin_lock(&fs_info->ordered_root_lock);
3883 	list_splice_init(&fs_info->ordered_roots, &splice);
3884 	while (!list_empty(&splice)) {
3885 		root = list_first_entry(&splice, struct btrfs_root,
3886 					ordered_root);
3887 		list_move_tail(&root->ordered_root,
3888 			       &fs_info->ordered_roots);
3889 
3890 		spin_unlock(&fs_info->ordered_root_lock);
3891 		btrfs_destroy_ordered_extents(root);
3892 
3893 		cond_resched();
3894 		spin_lock(&fs_info->ordered_root_lock);
3895 	}
3896 	spin_unlock(&fs_info->ordered_root_lock);
3897 }
3898 
3899 static int btrfs_destroy_delayed_refs(struct btrfs_transaction *trans,
3900 				      struct btrfs_root *root)
3901 {
3902 	struct rb_node *node;
3903 	struct btrfs_delayed_ref_root *delayed_refs;
3904 	struct btrfs_delayed_ref_node *ref;
3905 	int ret = 0;
3906 
3907 	delayed_refs = &trans->delayed_refs;
3908 
3909 	spin_lock(&delayed_refs->lock);
3910 	if (atomic_read(&delayed_refs->num_entries) == 0) {
3911 		spin_unlock(&delayed_refs->lock);
3912 		btrfs_info(root->fs_info, "delayed_refs has NO entry");
3913 		return ret;
3914 	}
3915 
3916 	while ((node = rb_first(&delayed_refs->href_root)) != NULL) {
3917 		struct btrfs_delayed_ref_head *head;
3918 		bool pin_bytes = false;
3919 
3920 		head = rb_entry(node, struct btrfs_delayed_ref_head,
3921 				href_node);
3922 		if (!mutex_trylock(&head->mutex)) {
3923 			atomic_inc(&head->node.refs);
3924 			spin_unlock(&delayed_refs->lock);
3925 
3926 			mutex_lock(&head->mutex);
3927 			mutex_unlock(&head->mutex);
3928 			btrfs_put_delayed_ref(&head->node);
3929 			spin_lock(&delayed_refs->lock);
3930 			continue;
3931 		}
3932 		spin_lock(&head->lock);
3933 		while ((node = rb_first(&head->ref_root)) != NULL) {
3934 			ref = rb_entry(node, struct btrfs_delayed_ref_node,
3935 				       rb_node);
3936 			ref->in_tree = 0;
3937 			rb_erase(&ref->rb_node, &head->ref_root);
3938 			atomic_dec(&delayed_refs->num_entries);
3939 			btrfs_put_delayed_ref(ref);
3940 		}
3941 		if (head->must_insert_reserved)
3942 			pin_bytes = true;
3943 		btrfs_free_delayed_extent_op(head->extent_op);
3944 		delayed_refs->num_heads--;
3945 		if (head->processing == 0)
3946 			delayed_refs->num_heads_ready--;
3947 		atomic_dec(&delayed_refs->num_entries);
3948 		head->node.in_tree = 0;
3949 		rb_erase(&head->href_node, &delayed_refs->href_root);
3950 		spin_unlock(&head->lock);
3951 		spin_unlock(&delayed_refs->lock);
3952 		mutex_unlock(&head->mutex);
3953 
3954 		if (pin_bytes)
3955 			btrfs_pin_extent(root, head->node.bytenr,
3956 					 head->node.num_bytes, 1);
3957 		btrfs_put_delayed_ref(&head->node);
3958 		cond_resched();
3959 		spin_lock(&delayed_refs->lock);
3960 	}
3961 
3962 	spin_unlock(&delayed_refs->lock);
3963 
3964 	return ret;
3965 }
3966 
3967 static void btrfs_destroy_delalloc_inodes(struct btrfs_root *root)
3968 {
3969 	struct btrfs_inode *btrfs_inode;
3970 	struct list_head splice;
3971 
3972 	INIT_LIST_HEAD(&splice);
3973 
3974 	spin_lock(&root->delalloc_lock);
3975 	list_splice_init(&root->delalloc_inodes, &splice);
3976 
3977 	while (!list_empty(&splice)) {
3978 		btrfs_inode = list_first_entry(&splice, struct btrfs_inode,
3979 					       delalloc_inodes);
3980 
3981 		list_del_init(&btrfs_inode->delalloc_inodes);
3982 		clear_bit(BTRFS_INODE_IN_DELALLOC_LIST,
3983 			  &btrfs_inode->runtime_flags);
3984 		spin_unlock(&root->delalloc_lock);
3985 
3986 		btrfs_invalidate_inodes(btrfs_inode->root);
3987 
3988 		spin_lock(&root->delalloc_lock);
3989 	}
3990 
3991 	spin_unlock(&root->delalloc_lock);
3992 }
3993 
3994 static void btrfs_destroy_all_delalloc_inodes(struct btrfs_fs_info *fs_info)
3995 {
3996 	struct btrfs_root *root;
3997 	struct list_head splice;
3998 
3999 	INIT_LIST_HEAD(&splice);
4000 
4001 	spin_lock(&fs_info->delalloc_root_lock);
4002 	list_splice_init(&fs_info->delalloc_roots, &splice);
4003 	while (!list_empty(&splice)) {
4004 		root = list_first_entry(&splice, struct btrfs_root,
4005 					 delalloc_root);
4006 		list_del_init(&root->delalloc_root);
4007 		root = btrfs_grab_fs_root(root);
4008 		BUG_ON(!root);
4009 		spin_unlock(&fs_info->delalloc_root_lock);
4010 
4011 		btrfs_destroy_delalloc_inodes(root);
4012 		btrfs_put_fs_root(root);
4013 
4014 		spin_lock(&fs_info->delalloc_root_lock);
4015 	}
4016 	spin_unlock(&fs_info->delalloc_root_lock);
4017 }
4018 
4019 static int btrfs_destroy_marked_extents(struct btrfs_root *root,
4020 					struct extent_io_tree *dirty_pages,
4021 					int mark)
4022 {
4023 	int ret;
4024 	struct extent_buffer *eb;
4025 	u64 start = 0;
4026 	u64 end;
4027 
4028 	while (1) {
4029 		ret = find_first_extent_bit(dirty_pages, start, &start, &end,
4030 					    mark, NULL);
4031 		if (ret)
4032 			break;
4033 
4034 		clear_extent_bits(dirty_pages, start, end, mark, GFP_NOFS);
4035 		while (start <= end) {
4036 			eb = btrfs_find_tree_block(root, start,
4037 						   root->leafsize);
4038 			start += root->leafsize;
4039 			if (!eb)
4040 				continue;
4041 			wait_on_extent_buffer_writeback(eb);
4042 
4043 			if (test_and_clear_bit(EXTENT_BUFFER_DIRTY,
4044 					       &eb->bflags))
4045 				clear_extent_buffer_dirty(eb);
4046 			free_extent_buffer_stale(eb);
4047 		}
4048 	}
4049 
4050 	return ret;
4051 }
4052 
4053 static int btrfs_destroy_pinned_extent(struct btrfs_root *root,
4054 				       struct extent_io_tree *pinned_extents)
4055 {
4056 	struct extent_io_tree *unpin;
4057 	u64 start;
4058 	u64 end;
4059 	int ret;
4060 	bool loop = true;
4061 
4062 	unpin = pinned_extents;
4063 again:
4064 	while (1) {
4065 		ret = find_first_extent_bit(unpin, 0, &start, &end,
4066 					    EXTENT_DIRTY, NULL);
4067 		if (ret)
4068 			break;
4069 
4070 		/* opt_discard */
4071 		if (btrfs_test_opt(root, DISCARD))
4072 			ret = btrfs_error_discard_extent(root, start,
4073 							 end + 1 - start,
4074 							 NULL);
4075 
4076 		clear_extent_dirty(unpin, start, end, GFP_NOFS);
4077 		btrfs_error_unpin_extent_range(root, start, end);
4078 		cond_resched();
4079 	}
4080 
4081 	if (loop) {
4082 		if (unpin == &root->fs_info->freed_extents[0])
4083 			unpin = &root->fs_info->freed_extents[1];
4084 		else
4085 			unpin = &root->fs_info->freed_extents[0];
4086 		loop = false;
4087 		goto again;
4088 	}
4089 
4090 	return 0;
4091 }
4092 
4093 void btrfs_cleanup_one_transaction(struct btrfs_transaction *cur_trans,
4094 				   struct btrfs_root *root)
4095 {
4096 	btrfs_destroy_ordered_operations(cur_trans, root);
4097 
4098 	btrfs_destroy_delayed_refs(cur_trans, root);
4099 
4100 	cur_trans->state = TRANS_STATE_COMMIT_START;
4101 	wake_up(&root->fs_info->transaction_blocked_wait);
4102 
4103 	cur_trans->state = TRANS_STATE_UNBLOCKED;
4104 	wake_up(&root->fs_info->transaction_wait);
4105 
4106 	btrfs_destroy_delayed_inodes(root);
4107 	btrfs_assert_delayed_root_empty(root);
4108 
4109 	btrfs_destroy_marked_extents(root, &cur_trans->dirty_pages,
4110 				     EXTENT_DIRTY);
4111 	btrfs_destroy_pinned_extent(root,
4112 				    root->fs_info->pinned_extents);
4113 
4114 	cur_trans->state =TRANS_STATE_COMPLETED;
4115 	wake_up(&cur_trans->commit_wait);
4116 
4117 	/*
4118 	memset(cur_trans, 0, sizeof(*cur_trans));
4119 	kmem_cache_free(btrfs_transaction_cachep, cur_trans);
4120 	*/
4121 }
4122 
4123 static int btrfs_cleanup_transaction(struct btrfs_root *root)
4124 {
4125 	struct btrfs_transaction *t;
4126 
4127 	mutex_lock(&root->fs_info->transaction_kthread_mutex);
4128 
4129 	spin_lock(&root->fs_info->trans_lock);
4130 	while (!list_empty(&root->fs_info->trans_list)) {
4131 		t = list_first_entry(&root->fs_info->trans_list,
4132 				     struct btrfs_transaction, list);
4133 		if (t->state >= TRANS_STATE_COMMIT_START) {
4134 			atomic_inc(&t->use_count);
4135 			spin_unlock(&root->fs_info->trans_lock);
4136 			btrfs_wait_for_commit(root, t->transid);
4137 			btrfs_put_transaction(t);
4138 			spin_lock(&root->fs_info->trans_lock);
4139 			continue;
4140 		}
4141 		if (t == root->fs_info->running_transaction) {
4142 			t->state = TRANS_STATE_COMMIT_DOING;
4143 			spin_unlock(&root->fs_info->trans_lock);
4144 			/*
4145 			 * We wait for 0 num_writers since we don't hold a trans
4146 			 * handle open currently for this transaction.
4147 			 */
4148 			wait_event(t->writer_wait,
4149 				   atomic_read(&t->num_writers) == 0);
4150 		} else {
4151 			spin_unlock(&root->fs_info->trans_lock);
4152 		}
4153 		btrfs_cleanup_one_transaction(t, root);
4154 
4155 		spin_lock(&root->fs_info->trans_lock);
4156 		if (t == root->fs_info->running_transaction)
4157 			root->fs_info->running_transaction = NULL;
4158 		list_del_init(&t->list);
4159 		spin_unlock(&root->fs_info->trans_lock);
4160 
4161 		btrfs_put_transaction(t);
4162 		trace_btrfs_transaction_commit(root);
4163 		spin_lock(&root->fs_info->trans_lock);
4164 	}
4165 	spin_unlock(&root->fs_info->trans_lock);
4166 	btrfs_destroy_all_ordered_extents(root->fs_info);
4167 	btrfs_destroy_delayed_inodes(root);
4168 	btrfs_assert_delayed_root_empty(root);
4169 	btrfs_destroy_pinned_extent(root, root->fs_info->pinned_extents);
4170 	btrfs_destroy_all_delalloc_inodes(root->fs_info);
4171 	mutex_unlock(&root->fs_info->transaction_kthread_mutex);
4172 
4173 	return 0;
4174 }
4175 
4176 static struct extent_io_ops btree_extent_io_ops = {
4177 	.readpage_end_io_hook = btree_readpage_end_io_hook,
4178 	.readpage_io_failed_hook = btree_io_failed_hook,
4179 	.submit_bio_hook = btree_submit_bio_hook,
4180 	/* note we're sharing with inode.c for the merge bio hook */
4181 	.merge_bio_hook = btrfs_merge_bio_hook,
4182 };
4183